Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/17/15
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
315 PM MST FRI MAY 15 2015
.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.
&&
.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE THROUGH THE REGION THIS EVENING INTO
EARLY SATURDAY MORNING...RESULTING IN A CONTINUED PERIOD OF SHOWERS
AND ISOLATED THUNDERSTORMS ALONG WITH MUCH COOLER TEMPERATURES. A
GRADUAL WARMING TREND WILL COMMENCE THIS WEEKEND AS HIGH PRESSURE
SLOWLY BUILDS INTO THE AREA...BUT TEMPERATURES ARE FORECAST TO REMAIN
BELOW NORMAL VALUES FOR MID MAY. ANOTHER COOL BUT WEAKER PACIFIC
DISTURBANCE IS FORECAST ON MONDAY...WITH A SLIGHT CHANCE OF SHOWERS.
CLEARING SKIES WITH A WARMING TREND IS FORECAST NEXT TUESDAY THROUGH
FRIDAY.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO SLOWLY MOVE ONSHORE ACROSS
SOUTHERN CALIFORNIA...WITH THE BACK EDGE OF THE RAINFALL ALREADY
MOVING THROUGH THE INLAND EMPIRE. RAINFALL CONTINUES TO SPREAD
THROUGH SOUTHEAST CALIFORNIA INTO CENTRAL ARIZONA...WITH MOST
LOCATIONS IN THE FORECAST AREA SEEING AT LEAST A TRACE OF RAINFALL
THUS FAR. THE HIGHEST RAINFALL AMOUNTS THUS FAR HAVE BEEN IN AND
AROUND THE ANTHEM/CAVE CREEK/CAREFREE AREA /APPROX 0.43 INCHES AS OF
20Z/ DUE TO TRAINING THUNDERSTORMS EARLIER IN THE DAY.
IN THE VERY SHORT TERM /THROUGH THIS EVENING/...THE PAST SEVERAL
RUNS OF THE HRRR HAVE REMAINED REMARKABLY CONSISTENT IN SHOWING 2 OR
3 WAVES OF PRECIPITATION MOVING THROUGH THE LOWER AZ DESERTS...THE
FIRST OF WHICH SHOULD ARRIVE BY 21Z...ANOTHER AROUND 00Z...AND A
THIRD AROUND 06Z. REGIONAL RADAR AND WV SATELLITE IMAGERY SUGGESTS
THIS SOLUTION MAY ACTUALLY VERIFY AS ADVERTISED...AS THERE ARE
NUMEROUS CIRCULATIONS EVIDENT TO THE WEST OF PHOENIX. SINCE RAIN IS
ALREADY FALLING ACROSS MOST OF THE AREA AND IS EXPECTED TO CONTINUE
FOR THE NEXT SEVERAL HOURS...I WILL MAINTAIN 100 POPS ACROSS MOST OF
THE AREA. CONDITIONS WILL IMPROVE FROM WEST TO EAST THIS
EVENING...WITH RAINFALL WRAPPING UP FOR GOOD BEFORE MIDNIGHT ACROSS
SOUTHEAST CALIFORNIA. BUFR SOUNDINGS CONTINUE TO REVEAL A PERSISTENT
PERIOD OF 100-200 J/KG OF ELEVATED CAPE THIS EVENING AND OVERNIGHT
AND I WILL LEAVE THE MENTION OF THUNDER IN THE FORECAST ACCORDINGLY.
AS FOR QPF...EXPECTING A BROAD AREA OF QUARTER TO HALF INCH AMOUNTS
ACROSS THE DESERTS...WITH AMOUNTS APPROACHING THREE QUARTERS OF AN
INCH TO THE NORTH AND EAST OF PHOENIX.
&&
.PREVIOUS DISCUSSION...
A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL CONTINUE OVER THE
MOUNTAINS OF SOUTHERN GILA COUNTY THROUGH SATURDAY AFTERNOON.
SUNDAY...A BREAK IN THE WEATHER IS FORECAST WITH DRY AND CONTINUED
BELOW NORMAL TEMPERATURES AHEAD OF ANOTHER STRONG PACIFIC STORM
FORECAST FOR MONDAY.
MONDAY...ANOTHER UNSEASONABLY STRONG AND COLD PACIFIC STORM IS
FORECAST TO MOVE INTO THE REGION MONDAY...HOWEVER THIS SYSTEM WILL
NOT BE AS COLD...MOIST...NOR AS DYNAMICAL AS TODAYS/FRIDAY MAY 15TH
EVENT. NONE-THE-LESS...A SLIGHT CHANCE OF SHOWERS ARE FORECAST TO
SPREAD FROM WEST TO EAST...OR FROM SOUTHEAST CA MONDAY MORNING TO
SOUTH CENTRAL AZ BY AFTERNOON. 500/300 MB HEIGHT FALLS ARE FORECAST
TO BE MODERATELY STRONG ACROSS SOUTHWEST AND SOUTH CENTRAL AZ...OR
SIGNIFICANT ENOUGH NOT TO IGNORE THE SLIGHT PRECIP THREAT. CLEARING
SKIES MONDAY NIGHT EVERYWHERE.
TUESDAY...DRY SOUTHWESTERLY FLOW ALOFT IS FORECAST WITH OCCASIONAL
HIGH CLOUDS AND WARMER TEMPERATURES EACH DAY. THE WARMEST DAY WILL
BE THURSDAY...HOWEVER TEMPERATURES WILL STILL BE SLIGHTLY BELOW
NORMAL GENERALLY BY 5 DEGREES...I.E. LOWER 90S ON THE DESERTS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LOW PRESSURE SYSTEM MOVING THROUGH DESERT SOUTHWEST TODAY AND
SATURDAY. ANTICIPATE SCATTERED SHOWERS...AND A STRAY THUNDERSTORM...
THROUGH THE AFTERNOON WITH CIGS GENERALLY 6-8 KFT MSL...LOCALLY
5-7 KFT MSL AND VIS 5-6SM WITH STRONGER SHOWERS. ANTICIPATE MORE
WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS AFT 02Z AND CIGS 3-5
KFT MSL BEFORE SHOWERS BEGIN TO IMPROVE 08Z. WIND DIRECTIONS WILL BE
ERRATIC FAVORING WESTERLY DIRECTIONS. GUSTS OF 20-25 KTS WILL BE
COMMON UNTIL ABOUT 06Z.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SCATTERED TO NUMEROUS SHOWERS...AND POSSIBLY A STRAY
THUNDERSTORM...WILL CONTINUE THROUGH THE DAYLIGHT HOURS BEFORE
TAPERING OFF AFTER 03Z. ANTICIPATE CIGS 6-8 KFT MSL...LOCALLY 4-6
KFT MSL. WIND DIRECTIONS WILL BE ERRATIC BUT FAVOR NORTHERLY
COMPONENTS. SUSTAINED SPEEDS WILL BE LESS THAN 10 KTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
A COUPLE OF FOLLOW-ON SYSTEMS WILL MOVE THROUGH THE DESERT SOUTHWEST
DURING THE NEXT WORK WEEK. THIS WILL KEEP TEMPERATURES BELOW NORMAL
AND THERE WILL BE BREEZY CONDITIONS AT TIMES. THESE SYSTEMS ARE NOT
EXPECTED TO BE AS MOIST AS THE PRECEDING SYSTEM AND THUS MINIMUM
HUMIDITIES WILL GENERALLY BE IN THE 10-15 PERCENT RANGE ON THE
LOWER ELEVATIONS. HOWEVER...NO CRITICAL CONDITIONS ARE EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/VASQUEZ
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
221 PM MST FRI MAY 15 2015
.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE THROUGH THE REGION THIS EVENING INTO
EARLY SATURDAY MORNING...RESULTING IN A CONTINUED PERIOD OF SHOWERS
AND ISOLATED THUNDERSTORMS ALONG WITH MUCH COOLER TEMPERATURES. A
GRADUAL WARMING TREND WILL COMMENCE THIS WEEKEND AS HIGH PRESSURE
SLOWLY BUILDS INTO THE AREA...BUT TEMPERATURES ARE FORECAST TO REMAIN
BELOW NORMAL VALUES FOR MID MAY. ANOTHER COOL BUT WEAKER PACIFIC
DISTURBANCE IS FORECAST ON MONDAY...WITH A SLIGHT CHANCE OF SHOWERS.
CLEARING SKIES WITH A WARMING TREND IS FORECAST NEXT TUESDAY THROUGH
FRIDAY.
&&
.DISCUSSION...
UPPER LEVEL LOW PRESSURE CONTINUES TO SLOWLY MOVE ONSHORE ACROSS
SOUTHERN CALIFORNIA...WITH THE BACK EDGE OF THE RAINFALL ALREADY
MOVING THROUGH THE INLAND EMPIRE. RAINFALL CONTINUES TO SPREAD
THROUGH SOUTHEAST CALIFORNIA INTO CENTRAL ARIZONA...WITH MOST
LOCATIONS IN THE FORECAST AREA SEEING AT LEAST A TRACE OF RAINFALL
THUS FAR. THE HIGHEST RAINFALL AMOUNTS THUS FAR HAVE BEEN IN AND
AROUND THE ANTHEM/CAVE CREEK/CAREFREE AREA /APPROX 0.43 INCHES AS OF
20Z/ DUE TO TRAINING THUNDERSTORMS EARLIER IN THE DAY.
IN THE VERY SHORT TERM /THROUGH THIS EVENING/...THE PAST SEVERAL
RUNS OF THE HRRR HAVE REMAINED REMARKABLY CONSISTENT IN SHOWING 2 OR
3 WAVES OF PRECIPITATION MOVING THROUGH THE LOWER AZ DESERTS...THE
FIRST OF WHICH SHOULD ARRIVE BY 21Z...ANOTHER AROUND 00Z...AND A
THIRD AROUND 06Z. REGIONAL RADAR AND WV SATELLITE IMAGERY SUGGESTS
THIS SOLUTION MAY ACTUALLY VERIFY AS ADVERTISED...AS THERE ARE
NUMEROUS CIRCULATIONS EVIDENT TO THE WEST OF PHOENIX. SINCE RAIN IS
ALREADY FALLING ACROSS MOST OF THE AREA AND IS EXPECTED TO CONTINUE
FOR THE NEXT SEVERAL HOURS...I WILL MAINTAIN 100 POPS ACROSS MOST OF
THE AREA. CONDITIONS WILL IMPROVE FROM WEST TO EAST THIS
EVENING...WITH RAINFALL WRAPPING UP FOR GOOD BEFORE MIDNIGHT ACROSS
SOUTHEAST CALIFORNIA. BUFR SOUNDINGS CONTINUE TO REVEAL A PERSISTENT
PERIOD OF 100-200 J/KG OF ELEVATED CAPE THIS EVENING AND OVERNIGHT
AND I WILL LEAVE THE MENTION OF THUNDER IN THE FORECAST ACCORDINGLY.
AS FOR QPF...EXPECTING A BROAD AREA OF QUARTER TO HALF INCH AMOUNTS
ACROSS THE DESERTS...WITH AMOUNTS APPROACHING THREE QUARTERS OF AN
INCH TO THE NORTH AND EAST OF PHOENIX.
&&
.PREVIOUS DISCUSSION...
A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL CONTINUE OVER THE
MOUNTAINS OF SOUTHERN GILA COUNTY THROUGH SATURDAY AFTERNOON.
SUNDAY...A BREAK IN THE WEATHER IS FORECAST WITH DRY AND CONTINUED
BELOW NORMAL TEMPERATURES AHEAD OF ANOTHER STRONG PACIFIC STORM
FORECAST FOR MONDAY.
MONDAY...ANOTHER UNSEASONABLY STRONG AND COLD PACIFIC STORM IS
FORECAST TO MOVE INTO THE REGION MONDAY...HOWEVER THIS SYSTEM WILL
NOT BE AS COLD...MOIST...NOR AS DYNAMICAL AS TODAYS/FRIDAY MAY 15TH
EVENT. NONE-THE-LESS...A SLIGHT CHANCE OF SHOWERS ARE FORECAST TO
SPREAD FROM WEST TO EAST...OR FROM SOUTHEAST CA MONDAY MORNING TO
SOUTH CENTRAL AZ BY AFTERNOON. 500/300 MB HEIGHT FALLS ARE FORECAST
TO BE MODERATELY STRONG ACROSS SOUTHWEST AND SOUTH CENTRAL AZ...OR
SIGNIFICANT ENOUGH NOT TO IGNORE THE SLIGHT PRECIP THREAT. CLEARING
SKIES MONDAY NIGHT EVERYWHERE.
TUESDAY...DRY SOUTHWESTERLY FLOW ALOFT IS FORECAST WITH OCCASIONAL
HIGH CLOUDS AND WARMER TEMPERATURES EACH DAY. THE WARMEST DAY WILL
BE THURSDAY...HOWEVER TEMPERATURES WILL STILL BE SLIGHTLY BELOW
NORMAL GENERALLY BY 5 DEGREES...I.E. LOWER 90S ON THE DESERTS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LARGE AND STRONG AREA OF PACIFIC LOW PRESSURE WILL MOVE INTO THE
AREA TODAY...FILLING IN MID-LEVEL CIGS AND MAINTAINING SOME WESTERLY
COMPONENT TO WINDS THROUGH THE DAY. SPEEDS WILL BE UNDER THOSE
OBSERVED ON THURSDAY WITH GUSTS INTO THE UPPER TEENS. VCSH ACTIVITY
WILL CONTINUE TO PERCOLATE ACROSS SOUTH-CENTRAL AZ INTO THE
AFTERNOON BEFORE BECOMING MORE WIDESPREAD AND PERSISTENT IN NATURE.
THE PERIOD OF STEADY RAINFALL...AND POTENTIAL FOR AT LEAST VCTS...IS
PROGGED FOR EARLY EVE THROUGH AROUND MIDNIGHT LOCAL. BKN TO OVC CIGS
EXPECTED TO FALL AOB 5K FEET DURING THE RAIN EVENT...WITH SCT CLOUD
LAYERS AS LOW AS 2-3 K FEET...AND VISIBILITIES FALLING INTO THE 3-5
MILE RANGE. WIND HEADINGS DURING THE ONSET OF THE HEAVIER RAINFALL
ARE A LITTLE TRICKIER TO CAPTURE... BKN-OVC CIGS ARE
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ON AND OFF RAIN SHOWER ACTIVITY WILL CONTINUE THROUGH MUCH OF THE
DAY AS AN AREA OF STRONG PACIFIC LOW AND ITS ASSOCIATED COLD FRONT
MOVE THROUGH THE AREA. WESTERLY WINDS TO PERSIST FOR KIPL WITH
SPEEDS GNLY 10-15KTS AND SOUTHERLY WINDS FOR KBLH WITH SIMILAR
SPEEDS.SHOWERS WILL LIKELY PUSH CIGS DOWN INTO THE 3-5K FEET RANGE
BEFORE GRADUALLY CLEARING/THINNING FRIDAY EVENING/OVERNIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
FAIRLY ACTIVE STORM PATTERN WILL STAY OVER THE WEST AND DIP BACK
THROUGH THE SOUTHWEST STATES THROUGH THE WEEK. IN THE WAKE OF
SATURDAY`S STORM... DRIER CONDITIONS WILL OVERSPREAD THE REGION
SUNDAY. ANOTHER STORM SYSTEM WILL EXPAND INTO THE GREAT BASIN BY THE
MIDDLE OF THE WEEK...AND WHILE LITTLE TO NO PRECIPITATION WILL
ACCOMPANY THIS STORM...MOISTURE LEVELS WILL REMAIN UNSEASONABLY
HIGH. AFTERNOON HUMIDITY LEVELS WILL ONLY FALL INTO A 15 TO 25
PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY AS TEMPERATURES HOVER
SLIGHTLY BELOW NORMAL. WIND SPEEDS DO NOT LOOK UNUSUALLY
STRONGER...WITH JUST THE TYPICAL AFTERNOON UPSLOPE GUSTINESS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/VASQUEZ
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1035 PM MST THU MAY 14 2015
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
STRONG LOW PRESSURE WILL BRING MUCH COOLER TEMPERATURES TO THE REGION
ALONG WITH AN INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS. AS THE
LOW EXITS THE REGION ON SATURDAY...RAIN CHANCES DIMINISH AND
TEMPERATURES RECOVER SLIGHTLY. DRIER AND WARMER CONDITIONS RETURN FOR
SUNDAY INTO NEXT WEEK...BUT EXPECT CONTINUED BELOW NORMAL
TEMPERATURES.
&&
.DISCUSSION... A RATHER PLEASANT...AND BREEZY WEATHER REGIME IS
OCCURRING ACROSS THE REGION THIS EVENING AS A VERY STRONG...AND
MOIST UPPER LOW CENTER APPROACHES FROM THE WEST...WITH MOST LOWER
DESERT LOCATIONS NOW SEEING TEMPERATURES IN THE 60S AND LOW 70S AT
THIS HOUR. ALTHOUGH SOME VIRGA/LIGHT SHOWER ACTIVITY IS ALREADY
BEING DETECTED ON THE 88D RADAR ACROSS SW ARIZONA...WHICH HAS BEEN
HANDLED WELL BY THE LATEST HRRR HI-RES MODEL RUN...IT STILL APPEARS
THAT SIGNIFICANT RAIN WILL NOT BE MOVING INTO OUR CWA UNTIL EARLY
FRIDAY MORNING AT THE EARLIEST...WHEN THE MAIN SHORTWAVE/UPPER LOW
CENTER...THAT CAN ALREADY BE SEEN ON LATEST IR SATELLITE IMAGERY
APPROACHING THE SOUTHERN CA COAST...BEGINS TO MOVE INLAND. AT THIS
POINT...IT APPEARS THAT RAINFALL WILL START DURING THE EARLY MORNING
HOURS ON FRIDAY ACROSS SE CA...THEN WILL REACH THE LOWER COLORADO
RIVER VALLEY BY LATE MORNING ON FRIDAY...THEN MOVE INTO SOUTH-
CENTRAL AZ BY LATE AFTERNOON ON FRIDAY. GIVEN THE TIMING OF THE
RAINFALL AND THE VERY COOL AIRMASS THAT WILL BE MOVING INTO OUR
REGION (850MB TEMPS IN THE 6-10C RANGE)...HIGH TEMPERATURES ON
FRIDAY ARE LIKELY TO BE ANYWHERE FROM 15 TO AS MUCH AS 25 DEGREES
BELOW NORMAL...MORE LIKE MID-LATE WINTER THAN MID-MAY...WITH THE
GREATEST DEPARTURES LIKELY TO BE SEEN OVER SE CA AND THE LOWER
COLORADO RIVER VALLEY. BASED ON THE LATEST (00Z) GFS AND NAM MODEL
RUNS...HAVE DECIDED TO LOWER TOMORROW/S HIGHS A BIT MORE. IT NOW
APPEARS THAT THE RECORD LOW MAX FOR MAY 15TH AT YUMA...WHICH NOW
STANDS AT 72 DEGREES...HAS A GOOD CHANCE OF BEING BROKEN TOMORROW.
HOWEVER...IT APPEARS THAT THE RECORD LOW MAX FOR PHOENIX OF 69
DEGREES FOR THE DATE WILL BE HARDER TO BREAK. LOWS ON SATURDAY
MORNING...GIVEN THE CLEARING SKIES AND THE STILL-COOL
AIRMASS...COULD DROP INTO THE 40S AT SOME OF THE COOLEST RURAL LOWER
DESERT LOCATIONS...NOT BAD FOR MID-MAY!
&&
.PREVIOUS DISCUSSION... UPPER LEVEL LOW PRESSURE CONTINUES TO DEEPEN
OFF THE CENTRAL CALIFORNIA COAST...WITH COPIOUS AMOUNTS OF MOISTURE
STREAMING INTO THE DESERT SOUTHWEST IN ADVANCE OF THE LOW. MOST OF
THE SHOWERS ASSOCIATED WITH THIS LOW REMAIN ACROSS THE L.A.
BASIN...ALTHOUGH PORTIONS OF NORTHERN ARIZONA ARE BEGINNING TO SEE
SHOWERS AND STORMS FILL IN SINCE APPROXIMATELY 18Z. ACROSS THE LOWER
DESERTS HOWEVER...SKIES REMAINED PARTLY CLOUDY WITH DRY CONDITIONS
AND GUSTY SOUTHWEST WINDS. THE STRONGEST WINDS THUS FAR HAVE BEEN
ACROSS SOUTHEAST CALIFORNIA ALTHOUGH WINDS SHOULD REMAIN IN THE
15G25KT RANGE ACROSS THE ENTIRE AREA THROUGH EARLY EVENING. FOR THAT
REASON I WILL HANG ONTO THE MENTIONS OF BLOWING DUST IN THE NORMALLY
FAVORED AREAS ACROSS SOUTHEAST CALIFORNIA...AS WELL AS SOUTH OF THE
PHOENIX METRO.
THE FORECAST REMAINS LARGELY ON TRACK...AS TODAY`S 12Z DETERMINISTIC
GUIDANCE MESHES WELL WITH 12Z GEFS AND NAEFS RUNS. LOW PRESSURE WILL
CONTINUE TO DEEPEN AND SPREAD MOISTURE INTO THE AREA THIS
EVENING/OVERNIGHT AND I WOULD EXPECT TO SEE SHOWERS SPILLING OVER THE
COASTAL MOUNTAINS BY 12Z FRIDAY. EXCELLENT AGREEMENT IS NOTED BETWEEN
TODAY`S GFS AND ECMWF INDICATING A SHORTWAVE TROUGH MOVING THROUGH
CENTRAL ARIZONA MID/LATER AFTERNOON. STRONG ISENTROPIC ASCENT
AND MID LEVEL MOISTURE CONVERGENCE VALUES WHICH RANK IN THE 90TH
PERCENTILE FOR MID MAY WILL ALLOW FOR WIDESPREAD SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT. WENT AHEAD AND INCREASED POPS QUITE A BIT
FOR FRIDAY INTO FRIDAY NIGHT...BASICALLY LOOKING AT A HIGH CONFIDENCE
EVENT WITH WIDESPREAD QUARTER TO HALF INCH RAIN AMOUNTS. WITH MLCAPES
ONLY TOPPING OUT BETWEEN 100-200 J/KG AT ANY GIVEN TIME DURING THIS
EVENT...NOT EXPECTING SEVERE WEATHER TO BE A MAJOR CONCERN. LIKEWISE
I WOULD NOT EXPECT SIGNIFICANT FLOODING BUT COULD ENVISION RUNNING
WASHES ESPECIALLY TO THE NORTH/EAST OF PHOENIX. CONSENSUS OF ALL
GUIDANCE YIELDS QPF AROUND 0.2-0.4 INCHES ACROSS THE DESERTS EAST OF
THE COLORADO RIVER...UPWARDS OF A HALF INCH IN THE MOUNTAINS EAST OF
PHOENIX. NATURALLY...LOWER AMOUNTS CAN BE EXPECTED DOWNWIND OF THE
COASTAL MOUNTAINS IN SOUTHEAST CALIFORNIA.
MUCH COOLER AIR ASSOCIATED WITH THE DEEP TROUGH WILL RESULT IN
SUBSTANTIALLY LOWER TEMPERATURES ON FRIDAY AND SATURDAY. HIGHS FRIDAY
SHOULD ONLY REACH INTO THE LOWER 70S ACROSS A GOOD PORTION OF THE
DESERTS WHILE RECOVERING BACK CLOSER TO 80 DEGREES FOR SATURDAY.
SYNOPTIC FLOW WILL BRIEFLY TURN ZONAL ON SUNDAY WITH 500MB HEIGHTS
RECOVERING BACK TO AROUND 572DM AND HIGH TEMPERATURES IN THE LOW TO
MID 80S.
A GRADUAL DRYING TREND WILL TAKE PLACE STARTING SATURDAY LASTING
INTO NEXT WEEK...BUT DON/T EXPECT TEMPERATURES TO RETURN BACK TO
NORMALS ANYTIME SOON. MODELS AGREE ON ANOTHER...BUT WEAKER...UPPER
LOW FORMING OFF THE WEST COAST ON SUNDAY AND MOVING THROUGH THE
DESERT SOUTHWEST MONDAY INTO EARLY TUESDAY. SO FAR IT DOESN/T LOOK
LIKE ENOUGH MOISTURE OR DYNAMICS WILL BE PRESENT TO WARRANT ANY
SLIGHT CHANCE POPS OVER OUR AREA...BUT THINGS MAY CHANGE. THIS NEXT
TROUGH WILL KEEP TEMPERATURES FROM GETTING BACK TO NORMAL AT LEAST
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A QUITE STRONG (FOR MAY) WEATHER SYSTEM APPROACHING FROM THE WEST IS
EXPECTED TO KEEP THE CURRENT WESTERLY WIND REGIME GOING WELL INTO
TONIGHT...WITH THE TYPICAL SWITCH TO SOUTHWESTERLY WINDS NOT
EXPECTED UNTIL NEAR DAYBREAK...THEN THE WESTERLY WINDS REDEVELOPING
AGAIN BY FRIDAY AFTERNOON...BUT AT LOWER SPEEDS THAN WHAT WE SAW
TODAY. THIS SAME WEATHER SYSTEM IS EXPECTED TO GRADUALLY LOWER CIGS
THROUGH THE REST OF TONIGHT AND INTO FRIDAY...WITH STEADY RAIN
EXPECTED TO DEVELOP BY LATE AFTERNOON ON FRIDAY...AND CONTINUING
INTO THE EVENING. BKN-OVC CIGS ARE EXPECTED TO FALL AOB 5K FEET
DURING THE RAIN EVENT...WITH SCT CLOUD LAYERS AS LOW AS 2-3 K
FEET...AND VISIBILITIES FALLING INTO THE 3-5 MILE RANGE.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
WINDS WILL CONTINUE TO GUST TO AROUND 30 KT BEFORE SUBSIDING THIS
EVENING. SHOWERS WILL DEVELOP AT KIPL AROUND 12Z FRIDAY...AND AT
KBLH BY 18Z FRIDAY. THIS SHOWERS WILL LIKELY PUSH CIGS DOWN INTO THE
3-5K FEET RANGE BEFORE GRADUALLY CLEARING/THINNING FRIDAY
EVENING/OVERNIGHT.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...DRIER CONDITIONS WILL OVERSPREAD THE
REGION SUNDAY IN THE WAKE OF THE LOW PRESSURE SYSTEM. ANOTHER STORM
SYSTEM WILL QUICKLY MOVE INTO THE GREAT BASIN BY THE MIDDLE OF THE
WEEK...AND WHILE LITTLE TO NO PRECIPITATION WILL ACCOMPANY THIS
STORM...MOISTURE LEVELS WILL REMAIN UNSEASONABLY HIGH. AFTERNOON
HUMIDITY LEVELS WILL ONLY FALL INTO A 15 TO 25 PERCENT RANGE WITH
GOOD OVERNIGHT RECOVERY AS TEMPERATURES HOVER SLIGHTLY BELOW NORMAL.
WIND SPEEDS DO NOT LOOK UNUSUALLY STRONGER...WITH JUST THE TYPICAL
AFTERNOON UPSLOPE GUSTINESS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/LEINS/KUHLMAN
AVIATION...PERCHA
FIRE WEATHER...MO/HIRSCH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
930 PM MST THU MAY 14 2015
&&
.SYNOPSIS...
STRONG LOW PRESSURE WILL BRING MUCH COOLER TEMPERATURES TO THE REGION
ALONG WITH AN INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS. AS THE
LOW EXITS THE REGION ON SATURDAY...RAIN CHANCES DIMINISH AND
TEMPERATURES RECOVER SLIGHTLY. DRIER AND WARMER CONDITIONS RETURN FOR
SUNDAY INTO NEXT WEEK...BUT EXPECT CONTINUED BELOW NORMAL
TEMPERATURES.
&&
.DISCUSSION... A RATHER PLEASANT...AND BREEZY WEATHER REGIME IS
OCCURRING ACROSS THE REGION THIS EVENING AS A VERY STRONG...AND
MOIST UPPER LOW CENTER APPROACHES FROM THE WEST...WITH MOST LOWER
DESERT LOCATIONS NOW SEEING TEMPERATURES IN THE 60S AND LOW 70S AT
THIS HOUR. ALTHOUGH SOME VIRGA/LIGHT SHOWER ACTIVITY IS ALREADY
BEING DETECTED ON THE 88D RADAR ACROSS SW ARIZONA...WHICH HAS BEEN
HANDLED WELL BY THE LATEST HRRR HI-RES MODEL RUN...IT STILL APPEARS
THAT SIGNIFICANT RAIN WILL NOT BE MOVING INTO OUR CWA UNTIL EARLY
FRIDAY MORNING AT THE EARLIEST...WHEN THE MAIN SHORTWAVE/UPPER LOW
CENTER...THAT CAN ALREADY BE SEEN ON LATEST IR SATELLITE IMAGERY
APPROACHING THE SOUTHERN CA COAST...BEGINS TO MOVE INLAND. AT THIS
POINT...IT APPEARS THAT RAINFALL WILL START DURING THE EARLY MORNING
HOURS ON FRIDAY ACROSS SE CA...THEN WILL REACH THE LOWER COLORADO
RIVER VALLEY BY LATE MORNING ON FRIDAY...THEN MOVE INTO SOUTH-
CENTRAL AZ BY LATE AFTERNOON ON FRIDAY. GIVEN THE TIMING OF THE
RAINFALL AND THE VERY COOL AIRMASS THAT WILL BE MOVING INTO OUR
REGION (850MB TEMPS IN THE 6-10C RANGE)...HIGH TEMPERATURES ON
FRIDAY ARE LIKELY TO BE ANYWHERE FROM 15 TO AS MUCH AS 25 DEGREES
BELOW NORMAL...MORE LIKE MID-LATE WINTER THAN MID-MAY...WITH THE
GREATEST DEPARTURES LIKELY TO BE SEEN OVER SE CA AND THE LOWER
COLORADO RIVER VALLEY. BASED ON THE LATEST (00Z) GFS AND NAM MODEL
RUNS...HAVE DECIDED TO LOWER TOMORROW/S HIGHS A BIT MORE. IT NOW
APPEARS THAT THE RECORD LOW MAX FOR MAY 15TH AT YUMA...WHICH NOW
STANDS AT 72 DEGREES...HAS A GOOD CHANCE OF BEING BROKEN TOMORROW.
HOWEVER...IT APPEARS THAT THE RECORD LOW MAX FOR PHOENIX OF 69
DEGREES FOR THE DATE WILL BE HARDER TO BREAK. LOWS ON SATURDAY
MORNING...GIVEN THE CLEARING SKIES AND THE STILL-COOL
AIRMASS...COULD DROP INTO THE 40S AT SOME OF THE COOLEST RURAL LOWER
DESERT LOCATIONS...NOT BAD FOR MID-MAY!
&&
.PREVIOUS DISCUSSION... UPPER LEVEL LOW PRESSURE CONTINUES TO DEEPEN
OFF THE CENTRAL CALIFORNIA COAST...WITH COPIOUS AMOUNTS OF MOISTURE
STREAMING INTO THE DESERT SOUTHWEST IN ADVANCE OF THE LOW. MOST OF
THE SHOWERS ASSOCIATED WITH THIS LOW REMAIN ACROSS THE L.A.
BASIN...ALTHOUGH PORTIONS OF NORTHERN ARIZONA ARE BEGINNING TO SEE
SHOWERS AND STORMS FILL IN SINCE APPROXIMATELY 18Z. ACROSS THE LOWER
DESERTS HOWEVER...SKIES REMAINED PARTLY CLOUDY WITH DRY CONDITIONS
AND GUSTY SOUTHWEST WINDS. THE STRONGEST WINDS THUS FAR HAVE BEEN
ACROSS SOUTHEAST CALIFORNIA ALTHOUGH WINDS SHOULD REMAIN IN THE
15G25KT RANGE ACROSS THE ENTIRE AREA THROUGH EARLY EVENING. FOR THAT
REASON I WILL HANG ONTO THE MENTIONS OF BLOWING DUST IN THE NORMALLY
FAVORED AREAS ACROSS SOUTHEAST CALIFORNIA...AS WELL AS SOUTH OF THE
PHOENIX METRO.
THE FORECAST REMAINS LARGELY ON TRACK...AS TODAY`S 12Z DETERMINISTIC
GUIDANCE MESHES WELL WITH 12Z GEFS AND NAEFS RUNS. LOW PRESSURE WILL
CONTINUE TO DEEPEN AND SPREAD MOISTURE INTO THE AREA THIS
EVENING/OVERNIGHT AND I WOULD EXPECT TO SEE SHOWERS SPILLING OVER THE
COASTAL MOUNTAINS BY 12Z FRIDAY. EXCELLENT AGREEMENT IS NOTED BETWEEN
TODAY`S GFS AND ECMWF INDICATING A SHORTWAVE TROUGH MOVING THROUGH
CENTRAL ARIZONA MID/LATER AFTERNOON. STRONG ISENTROPIC ASCENT
AND MID LEVEL MOISTURE CONVERGENCE VALUES WHICH RANK IN THE 90TH
PERCENTILE FOR MID MAY WILL ALLOW FOR WIDESPREAD SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT. WENT AHEAD AND INCREASED POPS QUITE A BIT
FOR FRIDAY INTO FRIDAY NIGHT...BASICALLY LOOKING AT A HIGH CONFIDENCE
EVENT WITH WIDESPREAD QUARTER TO HALF INCH RAIN AMOUNTS. WITH MLCAPES
ONLY TOPPING OUT BETWEEN 100-200 J/KG AT ANY GIVEN TIME DURING THIS
EVENT...NOT EXPECTING SEVERE WEATHER TO BE A MAJOR CONCERN. LIKEWISE
I WOULD NOT EXPECT SIGNIFICANT FLOODING BUT COULD ENVISION RUNNING
WASHES ESPECIALLY TO THE NORTH/EAST OF PHOENIX. CONSENSUS OF ALL
GUIDANCE YIELDS QPF AROUND 0.2-0.4 INCHES ACROSS THE DESERTS EAST OF
THE COLORADO RIVER...UPWARDS OF A HALF INCH IN THE MOUNTAINS EAST OF
PHOENIX. NATURALLY...LOWER AMOUNTS CAN BE EXPECTED DOWNWIND OF THE
COASTAL MOUNTAINS IN SOUTHEAST CALIFORNIA.
MUCH COOLER AIR ASSOCIATED WITH THE DEEP TROUGH WILL RESULT IN
SUBSTANTIALLY LOWER TEMPERATURES ON FRIDAY AND SATURDAY. HIGHS FRIDAY
SHOULD ONLY REACH INTO THE LOWER 70S ACROSS A GOOD PORTION OF THE
DESERTS WHILE RECOVERING BACK CLOSER TO 80 DEGREES FOR SATURDAY.
SYNOPTIC FLOW WILL BRIEFLY TURN ZONAL ON SUNDAY WITH 500MB HEIGHTS
RECOVERING BACK TO AROUND 572DM AND HIGH TEMPERATURES IN THE LOW TO
MID 80S.
A GRADUAL DRYING TREND WILL TAKE PLACE STARTING SATURDAY LASTING
INTO NEXT WEEK...BUT DON/T EXPECT TEMPERATURES TO RETURN BACK TO
NORMALS ANYTIME SOON. MODELS AGREE ON ANOTHER...BUT WEAKER...UPPER
LOW FORMING OFF THE WEST COAST ON SUNDAY AND MOVING THROUGH THE
DESERT SOUTHWEST MONDAY INTO EARLY TUESDAY. SO FAR IT DOESN/T LOOK
LIKE ENOUGH MOISTURE OR DYNAMICS WILL BE PRESENT TO WARRANT ANY
SLIGHT CHANCE POPS OVER OUR AREA...BUT THINGS MAY CHANGE. THIS NEXT
TROUGH WILL KEEP TEMPERATURES FROM GETTING BACK TO NORMAL AT LEAST
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
GUSTY WINDS AHEAD OF AN APPROACHING COLD FRONT WILL BE THE PRIMARY
AVIATION WEATHER IMPACT. WINDS WILL CONTINUE TO VEER TO THE SOUTHWEST
THIS AFTERNOON WITH GUSTS AS HIGH AS 30 KT. THE WINDY CONDITIONS WILL
ABATE THIS EVENING...THOUGH THE TYPICAL SHIFT TO DOWNSLOPE EASTERLY
IS NOT EXPECTED. INSTEAD...WINDS WILL BECOME SOUTHEASTERLY AROUND
12Z. CLOUDS WILL ALSO LOWER TO AROUND 6K FT FRIDAY MORNING.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
WINDS WILL CONTINUE TO GUST TO AROUND 30 KT BEFORE SUBSIDING THIS
EVENING. SHOWERS WILL DEVELOP ACROSS SOUTHEASTERN CALIFORNIA AROUND
12Z FRIDAY...WITH INCREASING CHANCES FOR PRECIPITATION THROUGH FRIDAY
AFTERNOON.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...DRIER CONDITIONS WILL OVERSPREAD THE
REGION SUNDAY IN THE WAKE OF THE LOW PRESSURE SYSTEM. ANOTHER STORM
SYSTEM WILL QUICKLY MOVE INTO THE GREAT BASIN BY THE MIDDLE OF THE
WEEK...AND WHILE LITTLE TO NO PRECIPITATION WILL ACCOMPANY THIS
STORM...MOISTURE LEVELS WILL REMAIN UNSEASONABLY HIGH. AFTERNOON
HUMIDITY LEVELS WILL ONLY FALL INTO A 15 TO 25 PERCENT RANGE WITH
GOOD OVERNIGHT RECOVERY AS TEMPERATURES HOVER SLIGHTLY BELOW NORMAL.
WIND SPEEDS DO NOT LOOK UNUSUALLY STRONGER...WITH JUST THE TYPICAL
AFTERNOON UPSLOPE GUSTINESS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/LEINS/KUHLMAN
AVIATION...MO
FIRE WEATHER...MO/HIRSCH
AREA FORECAST DISCUSSION
NWS EUREKA CA
343 PM PDT FRI MAY 15 2015
.SYNOPSIS...A SERIES OF UPPER LOW PRESSURE SYSTEMS WILL BRING
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO MAINLY THE
INTERIOR EACH AFTERNOON AND EVENING THROUGH MID NEXT WEEK.
OTHERWISE MOSTLY DRY WEATHER WITH BELOW NORMAL TEMPERATURES
WILL CONTINUE TO PREVAIL.
&&
.DISCUSSION...A BROAD AND COMPLEX UPPER LEVEL OVER THE GREAT
BASIN WILL CONTINUE TO SLOWLY TRACK EASTWARD AWAY FROM NORTHWEST
CALIFORNIA TONIGHT. WRAP AROUND MOISTURE AND PRECIP HAS BEEN
IMPACTING MAINLY SISKIYOU AND MODOC COUNTIES TODAY WITH ABUNDANT
CLOUD COVER AND SHOWERS. A FEW SPOTTY SHOWERS WERE SPILLING OVER
INTO MAINLY THE HIGHER ELEVATIONS OF ZONES 3 AND 4 THIS AFTERNOON.
THE ONSHORE NW FLOW IN THE LOWER LEVELS OF THE ATMOSPHERE HAS
CREATED MORE STABILITY TODAY AND NO LIGHTENING ACTIVITY IS
ANTICIPATED THIS EVENING.
A WEAK UPPER RIDGE WILL BUILD OVER THE AREA LATER TONIGHT INTO
SAT MORNING. THIS SHOULD CREATE STABILITY WITH VERY MINIMAL SHOWER
CHANCES OVER THE HIGHER TERRAIN. ANOTHER UPPER LOW WILL DIG
TOWARD THE NORTH COAST SAT AFTERNOON AND EVENING. WEAK
INSTABILITY WITH LONG THIN CAPE WILL PERSIST ACROSS THE EASTERN
PORTION OF THE AREA ON SAT AND A FEW LATE DAY SHOWERS ARE
EXPECTED OVER THE HIGHER TERRAIN. BUFKIT PROFILES SHOW A STABLE
LAYER ALOFT...SO CONFIDENCE WE WILL GET SUFFICIENT BOUNDARY LAYER
HEATING TO OVERCOME THE CIN FOR STORMS OVER THE TRINITY HORN AND
THE YOLLA BOLLYS IS NOT VERY HIGH.
SUNDAY IS STILL LOOKING LIKE THE BEST DAY FOR MORE INTERIOR
CONVECTION AS THE UPPER LOW APPROACHES CAPE MENDO AND THEN SLOLWY
MEANDERS SOUTHWARD THROUGH MONDAY MORNING. THE AXIS OF GREATEST
INSTABILITY AND PRECIP SHOULD SHIFT WESTWARD INTO WESTERN PORTIONS
OF HUMBOLDT AND DEL NORTE COUNTIES WITH PERHAPS SOME ACTIVITY IN
FAR NORTHERN MENDOCINO BY SUNDAY NIGHT. CONFIDENCE THUNDERSTORMS
WILL ADVECT OUT TO THE COAST IS NOT HIGH DUE TO THE LOW CAPE
VALUES AND FAIRLY LOW EQUILIBRIUM LEVELS. THE STORMS WILL SPROUT UP
WITH HEATING OVER THE MOUNTAINS THEN QUICKLY COLLAPSE...SIMILAR TO
THE STORMS YESTERDAY. THE GFS HAS BEEN A BIT TOO BROAD BRUSH WITH
THE CONVECTIVE PRECIP SO WILL CONTINUE TO USE THE NAM12 AS THE
PRIMARY GUIDANCE. THE HIRES-NMM AND HRRR HAVE BEEN MODELING THE
CONVECTION FAIRLY GOOOD AS WELL. THUS THE BROAD BRUSH GFS FIELDS
HAVE BEEN SCALED BACK. SHOWER CHANCES AND ISOLATED STORMS WILL
LIKELY PERSIST INTO MONDAY.
.LONG-TERM...TUE THROUGH FRI...NORTHWEST CALIFORNIA WILL REMAIN
WITHIN A LONG WAVE TROUGH PATTERN THROUGH MID-WEEK. ANOTHER
COMPLEX AND CONVOLUTED UPPER LOW WILL APPROACH ON TUE AND PRODUCE
INSTABILITY FOR AFTERNOON AND EVENING SHOWERS WITH ISOLATED TSTMS
PRIMARILY OVER THE INTERIOR THROUGH THU. THE GFS AND ECMWF
INDICATE SELY AND ELY FLOW ALOFT WHICH MAY SERVE TO PUSH A FEW
SHOWERS OUT TO THE COAST. THE CORE OF THE LOW ALOFT WILL PROBABLY
SWING SOUTHWARD TOWARD CENTRAL AND SOUTHERN CALIFORNIA ON FRI AND
THEN INTO THE GREAT BASIN/DESERT SW BY SAT PUTTING NW CALIFORNIA
IN DRIER AND MORE STABLE AIR AS A RIDGE ALOFT BUILDS TOWARD THE
COAST. THE ECMWF AND GEM WERE THE MOST AGGRESSIVE WITH BUILDING
THE RIDGE...WHILE THE GFS BRINGS ANOTHER UPPER LOW DOWN THE WEST
COAST IN THE NORTHERLY FLOW. FOR FRI...WILL MENTION ONLY A SLIGHT
CHANCE OF SHOWERS IN TRINITY COUNTY IN THE OUTSIDE CHANCE THE GFS
IS CORRECT.
&&
.AVIATION...SKIES ARE GENERALLY CLEAR ALONG THE IMMEDIATE COAST
HOWEVER SOME BUILD UP OF STRATO CU IS FORMING ON THE COASTAL HILLS.
AT THIS TIME COASTAL AIR TERMINALS ARE MAINLY VFR BUT CEC IS SHIFTING
FROM MVFR TO VFR AND THAT SHOULD CONTINUE THROUGH THE REMAINDER OF
THE AFTERNOON. CLOUDS AND LOW CEILINGS WILL LIKELY RETURN ALONG THE
COAST LATER TONIGHT. INTERIOR SITES SHOULD REMAIN VFR BUT KUKI MAY
BUT MAY SEE SOME FOG AND LOW CLOUDS AGAIN LATE TONIGHT BUT CHANCES
ARE LESS DUE TO SOME DRYING TODAY.
&&
.MARINE...THIS AFTERNOON WIND AND SEAS ARE TAME AND REMAINING BELOW
SCA THRESHOLDS HOWEVER SHORTER PERIOD WIND WAVES WILL BUILD A LITTLE
THIS EVENING. A SMALL SOUTHERLY SWELL IS ALSO PRESENT IN THE
WATERS...BUT WILL LIKELY DECAY THROUGH THE WEEKEND AND IS NOT
EXPECTED TO HAVE MAJOR IMPACTS. BEYOND THIS EVENING AND THROUGH THE
MIDDLE OF THE WEEK...NORTHERLY WINDS WILL REMAIN NEAR OR SLIGHTLY
BELOW SMALL CRAFT ADVISORY LEVEL...WHILE ANOTHER REINFORCING
WESTERLY SWELL WILL PROPAGATE THROUGH THE WATERS.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA
FOLLOW US ON FACEBOOK AND TWITTER AT:
HTTP://WWW.FACEBOOK.COM/NWSEUREKA
HTTP://WWW.TWITTER.COM/NWSEUREKA
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
353 AM PDT FRI MAY 15 2015
.SYNOPSIS...
A DISTURBANCE WILL CONTINUE SHOWERS AND ISOLATED THUNDERSTORMS
THROUGH THIS TODAY. LOCALLY HEAVY RAIN MAY PRODUCE FLASH
FLOODING...ESPECIALLY IN SAN DIEGO COUNTY. SNOW WILL FALL ABOVE
5500 TO 6000 FEET. THE SYSTEM WILL MOVE EAST OUT OF THE AREA
TONIGHT...AND FAIR BUT COOL WEATHER WILL OCCUR OVER THE WEEKEND
WITH AREAS OF MAINLY NIGHT AND MORNING LOW CLOUDS WEST OF THE
MOUNTAINS. A FEW SHOWERS ARE POSSIBLE NEXT MONDAY...BUT OTHERWISE
THE COOL WEATHER WITH AREAS OF COASTAL AND VALLEY LOW CLOUDS WILL
CONTINUE NEXT WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING
ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN
BERNARDINO COUNTIES...
AT 3 AM PDT...WATER VAPOR SATELLITE IMAGERY DISPLAYED A DEEP
UPPER-LEVEL LOW CENTERED JUST OFF THE COAST OF POINT CONCEPTION.
COMPOSITE RADAR IMAGERY SHOWED ISOLATED SHOWERS MOVING NORTHEAST
OVER PORTIONS OF THE COAST AND VALLEYS. AN UPDATED RAINFALL
TOTALS SUMMARY WAS ISSUED AT 215 AM. LINDBERGH FIELD IS THE WINNER
SO FAR AT 1.63 INCHES OF PRECIPITATION. MUCH OF THIS ACTUALLY FELL
IN A SHORT PERIOD AND CAUSED FLASH FLOODING IN PORTIONS OF THE
SAN DIEGO. THE 1.63 WAS ALSO A RECORD FOR LINDBERGH FOR THE
14TH...AND BLEW THE PREVIOUS RECORD OF 0.40 INCHES SET IN 1884 OUT
OF THE WATER.
ADDITIONAL PRECIPITATION REMAINS ON TRACK FOR SOUTHWEST CA FOR
TODAY. THE 15/0900 UTC HI-RES HRRR SHOWS THE NEXT WAVE MOVING
ACROSS THE AREA AS SOUTHERN CALIFORNIANS VENTURE OUT ON THEIR
MORNING COMMUTE. THE PLUME OF MOISTURE WILL BE SO DEEP IN THE
LOWER LEVELS THAT SHOWERS ARE FORECAST TO REACH THE DESERTS. LIGHT
TO MODERATE PRECIPITATION IS EXPECTED. HOWEVER...UNSTABLE AIR
ALOFT WILL ALLOW THE POSSIBILITY OF CONVECTION THIS MORNING AND
ESPECIALLY THIS AFTERNOON. STRONGER SHOWERS AND THUNDERSTORMS
COULD CREATE FLASH FLOODING AT TIMES...ESPECIALLY OVER/NEAR NEWER
BURN SCARS. A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS
AFTERNOON FOR PRONE AREAS. THE MAIN SURFACE LOW AND GREATEST AREAS
OF HEAVY SHOWERS WILL MOVE THROUGH THIS AFTERNOON...WITH SAN DIEGO
COUNTY HAVING THE BEST CHANCES OF PRECIPITATION. SNOW LEVELS THIS
MORNING ARE NEAR 5500 FT...AND WILL CLIMB THIS AFTERNOON TO NEAR
6500 FT. HIGHS TODAY WILL CHILLY FOR THIS TIME OF YEAR...RANGING
FROM 5 TO 10 DEGREES BELOW NORMAL ALONG THE COAST...AND 15 TO 30
DEGREES BELOW NORMAL INLAND.
...ADDITIONAL FORECAST PRECIP AMOUNTS THROUGH TONIGHT...
DESERTS.............0.05 TO 0.25 INCHES
COAST AND VALLEYS...0.50 TO 1.50 INCHES
MOUNTAINS...........0.50 TO 1.75 INCHES
...ADDITIONAL FORECAST SNOWFALL AMOUNTS THROUGH TONIGHT...
5500 TO 6500 FT...1 TO 2 INCHES
6500 TO 7500 FT...2 TO 4 INCHES
ABOVE 7500 FT.....4 TO 6 INCHES
THE WINTER WEATHER ADVISORY FOR PORTIONS OF THE SAN BERNARDINO
COUNTY AND RIVERSIDE COUNTY MOUNTAINS REMAINS IN EFFECT THROUGH
THIS AFTERNOON.
PRECIPITATION WILL QUICKLY END LATE TODAY AND OVERNIGHT AS THE
SYSTEM EJECTS EASTWARD. HIGH TEMPERATURES WILL WARM FEW DEGREES
EACH DAY THROUGH SUNDAY UNDER VERY WEAK RIDGING. HOWEVER...A DEEP
MARINE LAYER WILL REMAIN IN PLACE AND KEEP HIGH TEMPS CONTINUING
BELOW NORMAL FOR THIS TIME OF YEAR. ANOTHER LOW IS PROGGED TO MOVE
ACROSS CENTRAL CA MONDAY INTO TUESDAY. WITH LIMITED MOISTURE OVER
SOUTHERN CA...WIDESPREAD PRECIPITATION IS NOT ANTICIPATED AT THIS
TIME. CURRENTLY THERE IS A SLIGHT CHANCE OF PRECIP IN THE SAN
BERNARDINO COUNTY MOUNTAINS ON MONDAY. WEAK RIDGING BUILDS OVER
THE REGION TUESDAY NIGHT...THEN THE 15/0000 UTC ECMWF AND GFS
DIFFER IN THE PLACEMENT OF ANOTHER UPPER-LEVEL LOW ALONG THE WEST
COAST. THE GFS QUICKLY MOVES IT SOUTH ALONG THE COAST AND OVER THE
REGION EARLY THURSDAY...WHILE THE ECMWF IS SLOWER...PLACING THE
LOW OVER SW CA FRIDAY. FOR NOW...EXPECT BELOW NORMAL HIGH
TEMPERATURES AND A RELATIVELY DEEP MARINE LAYER NEXT WEEK.
&&
.AVIATION...
160949Z...WIDELY SCATTERED -SHRA CONTINUING THIS MORNING WITH MOSTLY
VFR CIGS/VIS PREVAILING. LOCAL MVFR CONDS POSSIBLE IN HEAVIER
SHOWERS. SHOWERS BECOMING HEAVIER AND MORE WIDESPREAD AFTER
12Z...WITH CIGS LOWERING TO 1500-2500 FT MSL AND VIS 2-4SM IN
SHOWERS...LOCALLY BLO 1000 FT MSL AND VIS DOWN TO 1SM. ISOLD TSRA
WITH SMALL HAIL ALSO POSSIBLE...MAINLY 16Z-02Z. SHOWERS TAPERING OFF
AFTER 16/02Z...ENDING OVERNIGHT. VARIABLE SCT-BKN CLOUD LAYERS AOA
2000 FT MSL AND COASTAL SLOPES OF THE MTNS OBSCURED TONIGHT INTO SAT
MORNING.
&&
.MARINE...
200 AM...A STORM SYSTEM WILL CONTINUE SHOWERS AND ISOLATED
THUNDERSTORMS OVER THE COASTAL WATERS THIS EVENING...INCREASING IN
COVERAGE LATER THIS MORNING. SMALL HAIL...GUSTY
WINDS...LIGHTNING...WATERSPOUTS...AND BRIEF HEAVY RAINFALL ARE
POSSIBLE WITH THUNDERSTORMS. A MARINE WEATHER
STATEMENT...LAXMWSSGX...REMAINS IN EFFECT. GUSTY NORTHWEST WINDS TO
25 KT WILL LIKELY DEVELOP BEHIND THE FRONT LATE THIS MORNING AND
CONTINUE THROUGH TONIGHT. CHOPPY SEAS AND HAZARDOUS CONDITIONS ARE
EXPECTED FOR SMALL CRAFT. A SMALL CRAFT ADVISORY REMAINS IN EFFECT
FROM FRIDAY MORNING THROUGH EARLY SAT MORNING. WINDS AND SEAS WILL
DIMINISH ON SATURDAY...WITH NO ADDITIONAL HAZARDOUS MARINE WEATHER
EXPECTED THROUGH TUESDAY.
&&
.SKYWARN...
SKYWARN ACTIVATION WILL LIKELY BE REQUESTED LATER THIS MORNING OR
EARLY THIS AFTERNOON.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR RIVERSIDE COUNTY
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN DIEGO COUNTY
COASTAL AREAS-SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY
VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS.
WINTER WEATHER ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR
RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT SATURDAY FOR WATERS FROM SAN
MATEO POINT TO THE MEXICAN BORDER EXTENDING 30 TO 60 NM OUT
INCLUDING SAN CLEMENTE ISLAND.
SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR COASTAL
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT
TO 30 NM.
&&
$$
PUBLIC...JJT
AVIATION/MARINE...SS
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
930 PM PDT THU MAY 14 2015
.SYNOPSIS...
A NORTH PACIFIC STORM SYSTEM WILL CONTINUE TO BRING SHOWERS AND
ISOLATED THUNDERSTORMS THROUGH FRIDAY. LOCALLY HEAVY RAIN MAY
PRODUCE FLASH FLOODING...ESPECIALLY IN SAN DIEGO COUNTY. SNOW WILL
FALL ABOVE 5500 TO 6000 FEET. THE SYSTEM WILL MOVE EAST OUT OF THE
AREA FRIDAY NIGHT...AND FAIR BUT COOL WEATHER WILL OCCUR OVER THE
WEEKEND WITH AREAS OF MAINLY NIGHT AND MORNING LOW CLOUDS WEST OF
THE MOUNTAINS. A FEW SHOWERS ARE POSSIBLE NEXT MONDAY...BUT
OTHERWISE THE COOL WEATHER WITH AREAS OF COASTAL AND VALLEY LOW
CLOUDS WILL CONTINUE.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING
ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN
BERNARDINO COUNTIES...
AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN
OCCURRING...WITH CONVECTIVE BANDING BRINGING LOCALLY HEAVY
RAINFALL OVER AN INCH WHERE TRAINING OF THE PRECIPITATION IS
OCCURRING ALONG THE BANDS. SAN DIEGO LINDBERGH FIELD HAD 1.51 INCHES
IN ABOUT 90 MINUTES...INCLUDING 0.71 INCHES IN 9 MINUTES...MORE
TYPICAL OF A CONVECTIVE STORM IN THE MIDWEST OR SOUTHEAST THAN SAN
DIEGO. FLASH FLOOD WARNING IS IN EFFECT FOR THE CITY OF SAN
DIEGO...AND WE HAVE HAD A REPORT OF FLOODING ALONG INTERSTATE 8.
PRECIPITABLE WATER VALUES OF AROUND ONE INCH ARE QUITE RARE FOR
MAY...AND THAT IS COMBINING WITH THE COLD AIR ALOFT...AROUND -22 DEG
C AT 500 MB...TO BRING THE POTENT CONVECTIVE CELLS. HRRR SHOWS THE
CONVECTIVE BANDING CONTINUING OVERNIGHT AHEAD OF THE MAIN LOW OVER
THE COASTAL WATERS...AND THIS WILL MEAN THAT SOME LOCATIONS WILL
HAVE HEAVY RAINFALL WHILE ADJACENT AREAS WILL HAVE RELATIVELY LIGHT
AMOUNTS...WITH HEAVY RAINFALL MOST LIKELY IN SAN DIEGO COUNTY AND
SOUTHWESTERN RIVERSIDE COUNTY. THE RAINFALL DOES BECOME MORE
WIDESPREAD AGAIN TOWARDS SUNRISE...BUT THE HRRR DOES SHOW THE
EAST-WEST ORIENTED FRONT THAT THE LOCAL WRF WAS ADVERTISING
YESTERDAY OVER THE COASTAL WATERS OFF NORTHERN SAN DIEGO COUNTY
WHICH COULD MEAN THAT THE FOCUS OF THE HEAVIEST PRECIP WILL BE IN
NORTHERN SAN DIEGO COUNTY IN THE MORNING...THEN THE NAM IS
INDICATING IT SHOULD SLIDE A BIT FURTHER SOUTH AS THE SURFACE LOW
OVER THE COASTAL WATERS SHIFTS SOUTHEAST. PRECIP AMOUNTS WILL BE
QUITE VARIABLE...BUT SAN DIEGO COUNTY WILL HAVE MOSTLY 1.0 TO 2.5
INCHES WITH LOCAL AMOUNTS TO 3 INCHES. NORTH OF SAN DIEGO COUNTY
WILL MOSTLY BE 1-2 INCHES. THE DESERTS WILL HAVE LESS...MOSTLY 0.1
TO 0.4 INCHES. SOME OROGRAPHICS HAVE OCCURRED TONIGHT...AS AMOUNTS
WERE ENHANCED ON THE SOUTHWEST SLOPES...INCLUDING AROUND PALOMAR
MOUNTAIN AND IN SAN BERNARDINO COUNTY. HOWEVER...WITH WINDS BECOMING
MORE SOUTHERLY AND MORE CYCLONIC AS THE LOW CENTER
APPROACHES...AND WE CONTINUE TO HAVE MORE CONVECTIVE THAN
STRATIFORM PRECIP...THE OROGRAPHIC EFFECT WILL BE LESS AND MOUNTAIN
AREAS WILL HAVE ONLY SLIGHTLY MORE PRECIP THAN COASTAL/VALLEY
LOCATIONS. REGARDING SNOW...THAT WILL ALSO BE HIGHLY VARIABLE...AND
WHILE AMOUNTS WILL GENERALLY BE 2-6 INCHES IN THE SAN BERNARDINO
COUNTY MOUNTAINS...ANY KIND OF TRAINING OF PRECIP COULD BRING HIGHER
LOCAL AMOUNTS...9 INCHES...POSSIBLY MORE. SNOW LEVELS WILL MOSTLY BE
5500-6000 FEET. NOT SURPRISINGLY...DAYTIME TEMPS WILL BE WELL BELOW
SEASONAL NORMALS...WITH SOME LOWER DESERT AREAS NOT EVEN MUCH ABOVE
70 FRIDAY.
MOST OF THE PRECIP SHOULD END EARLY FRIDAY NIGHT...BUT WITH VERY
LITTLE RIDGING BEHIND THIS LOW PRESSURE SYSTEM...TEMPS WILL REMAIN
BELOW NORMAL OVER THE WEEKEND...WITH HIGHS MOSTLY 10 DEG F BELOW
NORMAL. ANOTHER RATHER DEEP TROUGH WILL MOVE THROUGH MONDAY...THOUGH
WITH LIMITED MOISTURE. A FEW SHOWERS COULD STILL
DEVELOP...ESPECIALLY SINCE WE WILL LIKELY HAVE A DEEP MARINE LAYER
THEN. LONG-WAVE TROUGHING ALONG THE WEST COAST FOR MOST OF NEXT WEEK
WILL MEAN TEMPERATURES WILL REMAIN BELOW NORMAL FOR AWHILE WITH
OCCSAIONAL CLOUDS...ESPECIALLY WEST OF THE MOUNTAINS.
&&
.AVIATION...
150400Z...SCATTERED SHRA AND ISOLATED TSRA WILL CONTINUE ACROSS
PORTIONS OF THE REGION THIS EVENING...ESPECIALLY NEAR KSAN AND KCRQ.
NUMEROUS SHOWERS WILL DEVELOP AND MOVE ACROSS THE AREA EARLY FRIDAY
MORNING THROUGH EARLY FRIDAY AFTERNOON AS A FRONT TRAVERSES THE
REGION. CEILINGS WILL BE MOSTLY ABOVE 4000-5000 FT MSL...THEN LOWER
IN SHOWERS TO BETWEEN 1500 TO 2500 FT MSL IN SHOWERS. VIS WILL ALSO
LOWER TO BETWEEN 2-4SM IN SHOWERS...LOCALLY 1SM IN HEAVIER SHOWERS.
STRONG UP/DOWN DRAFTS...SMALL HAIL...LIGHTNING AND REDUCED VIS WILL
BE POSSIBLE IN THUNDERSTORMS. CONDITIONS WILL IMPROVE FRIDAY EVENING
AND FRIDAY NIGHT.
&&
.MARINE...
900 PM...A STORM SYSTEM WILL CONTINUE SHOWERS AND
THUNDERSTORMS ACROSS THE COASTAL WATERS THIS EVENING...AND INCREASE
IN COVERAGE TONIGHT AND FRIDAY MORNING. THUNDERSTORMS MAY CREATE
SMALL HAIL...GUSTY WINDS...LIGHTNING...AND BRIEF HEAVY RAINFALL.
WATERSPOUTS WILL ALSO BE POSSIBLE. A MARINE WEATHER
STATEMENT...LAXMWSSGX...HAS BEEN ISSUED. GUSTY SOUTH TO
SOUTHEASTERLY WINDS TO 30 KT WILL LIKELY DEVELOP FRIDAY MORNING AND
CONTINUE THROUGH THE AFTERNOON. CHOPPY SEAS AND HAZARDOUS CONDITIONS
ARE EXPECTED FOR SMALL CRAFT. A SMALL CRAFT ADVISORY HAS BEEN
ISSUED...LAXMWWSGX...AND GOES INTO EFFECT FRIDAY MORNING. WINDS AND
SEAS WILL DIMINISH FRIDAY NIGHT AND SATURDAY...WITH NO ADDITIONAL
HAZARDOUS MARINE WEATHER EXPECTED THROUGH MONDAY.
&&
.SKYWARN...
SKYWARN ACTIVATION WILL LIKELY BE NEEDED FRIDAY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 PM PDT
FRIDAY FOR RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY
MOUNTAINS.
FLASH FLOOD WATCH FROM 4 AM PDT FRIDAY THROUGH 6 PM FRIDAY FOR
RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-
SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SANTA
ANA MOUNTAINS AND FOOTHILLS-SAN DIEGO COUNTY COASTAL AREAS.
PZ...SMALL CRAFT ADVISORY FROM 5 AM FRIDAY TO 5 AM PDT SATURDAY FOR
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING
30 TO 60 NM OUT INCLUDING SAN CLEMENTE ISLAND.
SMALL CRAFT ADVISORY FROM 5 AM TO 11 PM PDT FRIDAY FOR COASTAL
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT
TO 30 NM.
&&
$$
PUBLIC...MAXWELL
AVIATION/MARINE...JJT
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1104 AM MDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1039 AM MDT FRI MAY 15 2015
CONVECTION HAS STARTED ALREADY OVER THE MOUNTAINS...FOOTHILLS AND
PALMER RIDGE. THERE ARE A FEW BOUNDARIES FLOATING AROUND THE
PLAINS RIGHT NOW. THE MAIN ONE IS ALONG THE SOUTHERN CWA BORDER THEN
IT IS ORIENTED SOUTHWEST/NORTHEAST UP THROUGH ELBERT COUNTY INTO
EAST ARAPAHOE AND ADAMS. THE SOUTH-SOUTHEASTERLIES WINDS SOUTH OF
IT ARE COMING OFF THE HIGHER TERRAIN AND THE DOWNSLOPING HAS DRIED
OUT DEW POINTS INTO THE 30S F. MOST OF THE PLAINS OF THE CWA HAVE
DEW POINTS IN THE MID 40S TO LOWER 50S F RIGHT NOW. THAT BOUNDARY
IS MOVING NORTHWARD SLOWLY BUT SHOULD PROVIDE THE IMPETUS FOR
THUNDERSTORMS TO DEVELOP AT SOME POINT IN THE NEXT COUPLE OF
HOURS. WILL MAKE SOME ADJUSTMENTS TO POPS AND CLOUD COVER...BUT
NOTHING MAJOR.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 459 AM MDT FRI MAY 15 2015
COMPLEX SITUATION TODAY AS SOUTHERLY FLOW STRENGTHENS AHEAD OF
THE UPPER LOW OVER SOUTHERN NEVADA. BIGGEST QUESTION IS THE
POSITION OF LOW LEVEL FEATURES ON THE PLAINS THIS AFTERNOON AND
THE AMOUNT OF HEAT AND MOISTURE AVAILABLE FOR CONVECTION. SEVERAL
FACTORS ARE FAVORABLE FOR SEVERE WEATHER...MOST NOTABLY STRONG
SHEAR AND A PLUME OF MOISTURE PUSHING WESTWARD ON THE NORTH SIDE
OF A SURFACE LOW/TROUGH THAT WILL BE IN EASTERN COLORADO. IT IS
ALSO LOOKING LIKE THERE WILL BE ENOUGH DRY MID LEVEL AIR TO ALLOW
A FAIR AMOUNT OF SUN OVER NORTHEAST COLORADO TODAY...WHILE THE
WESTWARD EXTENT OF THE GOOD MOISTURE MAY BE A BIT MORE THAN
PREVIOUSLY EXPECTED. ALWAYS HARD TO SECOND GUESS JUST HOW MUCH
MIXING OUT OF THE MOISTURE THERE WILL BE...CERTAINLY WEST OF THE
DRY LINE THIS WILL HAPPEN...BUT ON THE NORTH SIDE OF THE LOW THE
PLUME OF MOISTURE WRAPPING AROUND WILL NOT MIX AS MUCH. BIGGEST
QUESTION IS PROBABLY THE SHARPNESS OF THE LOW/TROUGH FEATURE WHICH
IS OFTEN UNDERDONE IN THE MODELS. AT THIS HOUR THE HRRR IS SHOWING
A PLUME OF EAST WINDS HOLDING 50 DEGREE DEW POINTS AND CAPES
AROUND 2000 J/KG ALONG THE NORTHERN BORDER BACK AS FAR AS WELD
COUNTY. HOWEVER IT ALSO SCOURS OUT THE MOISTURE IN AREAS FURTHER
SOUTH...DRYING OUT WASHINGTON COUNTY BY MID AFTERNOON BEFORE THE
CONVECTION GETS GOING.
A NEGATIVE FACTOR MAY BE TOO MUCH SOUTHERLY WIND. THIS MAY HELP
DRY THINGS OUT AND PUSH THE BETTER MOISTURE TO THE NORTH...AND MAY
ALSO REDUCE THE SHEAR AND ESPECIALLY THE HELICITY IF THE WIND
PROFILE WINDS UP BEING PRETTY LINEAR. THERE SHOULD BE A SWEET SPOT
WITH THE LOW LEVEL WINDS BACKED TO EASTERLY...MOST LIKELY NEAR OUR
NORTHERN BORDER OR JUST INTO NEBRASKA. THIS AREA WOULD HAVE THE
BEST THREAT OF SEVERE WEATHER AND A DECENT TORNADO THREAT. WILL GO
WITH THIS IDEA AS THE MOST LIKELY SCENARIO...WITH STRONG STORMS
DEVELOPING IN THE MOISTURE ALONG THE DRY LINE AND/OR NORTH OF THE
LOW/TROUGH WHERE CAPES WILL BE 1500-2000 J/KG...THEN PROPAGATING
NORTH WITH THE SEVERE THREAT INCREASING NEAR OUR NORTHERN BORDER.
OTHER STORMS WILL FORM ON THE BACK EDGE OF THE DRY SLOT...NEAR THE
FRONT RANGE/CHEYENNE RIDGE BUT SHOULD BE WEAKER WITH CAPES OF 500
J/KG NEAR THE MOUNTAINS AND IMPROVING A BIT AS THEY MOVE EAST INTO
THE MOISTURE TONGUE. STILL COULD BE SOME SEVERE THREAT HERE AS
WELL...MAINLY IN NORTHERN WELD COUNTY. OF COURSE IF THE LOW WINDS
UP BEING BETTER DEFINED THERE WOULD BE A MUCH HIGHER THREAT OF
SEVERE WEATHER ON THE NORTH AND NORTHEAST SIDE OF THE LOW.
RAISED HIGHS A LITTLE EXPECTING MORE SUN...STILL A FEW DEGREES
BELOW GUIDANCE AND IF IT IS A LITTLE WARMER THAT WILL HELP AS
WELL. TRENDED POPS MORE TOWARD THE IDEA OF A GOOD BREAK IN THE DRY
SLOT MUCH OF TODAY...WITH STORMS MOVING IN FROM THE WEST AND
DEVELOPING IN THE NORTH AND EAST IN THE LATE AFTERNOON. BEST
COVERAGE PROBABLY IN THE EARLY EVENING ON THE PLAINS...BUT
INTESITY SHOULD BE LESS THEN. SOME CLOUDS AND WEAK SHOWERS HANG ON
OVERNIGHT WITH A LITTLE COOLING ALOFT AND OVERALL INCREASE IN
MOISTURE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM MDT FRI MAY 15 2015
OVERALL TREND IN THE FORECAST IS THE SAME. THE NEXT SYSTEM WILL
IMPACT THE CWA ON SATURDAY. THE BROAD BUT CLOSED UPPER TROUGH WILL
STRETCH FROM THE NORTHERN ROCKIES TO THE DESERT SOUTHWEST AT 12Z
SATURDAY...WITH A MODERATE TO STRONG SLY FLOW OVER EASTERN
COLORADO. WEAK TO MODERATE MID AND UPPER LEVEL QG ASCENT WILL
REMAIN OVER NORTHEAST COLORADO THROUGH THE DAY...WITH PLENTY OF
MOISTURE IN PLACE. MAIN ISSUE WILL BE WHERE THE SFC LOW SETS UP
AND AT THIS TIME IT APPEARS TO BE ALONG THE EASTERN BORDER. IF
THIS OCCURS...THEN THE STRONG/SEVERE THUNDERSTORMS WILL LIKELY BE
EAST OF COLORADO...BUT CANNOT RULE OUT ONE OR TWO REACHING SEVERE
LEVELS ALONG THE BORDER WHERE THE BEST VERTICAL SHEAR WILL BE
PRESENT. IN AND AROUND DENVER FORECAST CAPES IN THE AFTERNOON NOT
BAD...800-900 J/KG. MOISTURE AOA 700 MB IN THE AFTN...BUT DRIER IN
THE LOWER LEVELS. IN THE MOUNTAINS...NO HIGHLIGHTS BUT COULD SEE
UP TO 5 INCHES ABOVE 10 KT THROUGH THE DAY SATURDAY.
SATURDAY NIGHT INTO SUNDAY...THE QG ASCENT SHIFTS TO THE NORTH AND
EAST WITH INCREASING QG DESCENT OVER THE REGION. THE MID LEVEL
TROUGH AXIS SLIDES EASTWARD SATURDAY EVENING...WITH SUBSIDENCE
IN PLACE AS A SHORT WAVE RIDGE PUSHES INTO THE STATE THROUGH
SUNDAY. SOME LINGERING SHOWERS IN THE HIGH COUNTRY WEST OF THE
CONTINENTAL DIVIDE...BUT DOWNSLOPE IN AND NEAR THE FRONT RANGE
FOOTHILLS SHOULD NEGATE MUCH OF THE PCPN IN THE 03Z-06Z WINDOW.
FOR SUNDAY AFTERNOON...SHOWERS AND A FEW STORMS ARE PROGGED TO
DEVELOP AS MID LEVEL MOISTURE AND AFTN HEATING WILL OFFSET THE
INFLUENCE OF THE RIDGE.
SUNDAY NIGHT...A SURFACE HIGH IS PROGGED TO PUSH A COLD FRONT INTO
THE FRONT RANGE IN THE EVENING. LINGERING SHOWERS AND ISOLATED
THUNDERSTORMS WILL LINGER THROUGH SUNDAY EVENING. NOT MUCH IN THE
WAY OF PCPN FM 06Z-18Z MONDAY. THE UPPER RIDGE WILL SHIFT TO THE
EAST WITH THE FLOW ALOFT BECOMING SOUTHWESTERLY AHEAD OF THE NEXT
DEVELOPING TROUGH. MUCH OF THE SHOWER/TSTM ACTIVITY ON MONDAY
AFTN WILL OCCUR IN THE HIGH COUNTRY. MDLS STILL PEG ANOTHER GOOD
CHC OF PCPN FOR MUCH OF THE CWA LATE MONDAY NIGHT THROUGH TUESDAY
EVENING. A MOIST SOUTHERLY FLOW ALOFT AHEAD OF THIS TROUGH...
OVERRUNNING AND STATIONARY FRONTAL BOUNDARY SITTING ALONG THE
FRONT RANGE/PALMER DIVIDE. THIS BROAD TROUGH IS PROGGED TO LIFT
NORTHWARD TUESDAY NIGHT...BUT NOT ENOUGH TO DRY THE REGION OUT ON
WEDNESDAY/THURSDAY. BEST CHC OF SHOWERS/TSTMS THOSE DAYS APPEAR TO
BE FROM THE FRONT RANGE EASTWARD WHERE THE BEST MOISTURE WILL BE.
OVERALL TEMPERATURES WL REMAIN COOLER THAN NORMAL...COLDEST ON
SATURDAY AND THEN TUESDAY/WEDNESDAY OF NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z SATURDAY MORNING)
ISSUED AT 1039 AM MDT FRI MAY 15 2015
AS MENTIONED ABOVE...THERE ARE A NUMBER OF BOUNDARIES FLOATING
AROUND WHICH WILL PLAY HAVOC WITH THE DIA WIND DIRECTIONS. THERE
IS A BOUNDARY WELL SOUTH OF DIA...STILL A FEW HOURS OUT OF BRING
SOUTHEASTERLIES TO THE AIRPORT. THERE IS CONVECTION STARTING IN
CENTRAL DOUGLAS COUNTY RIGHT WHICH MAY ACCELERATE THE ARRIVAL OF
THE SOUTHERLIES OR SOUTHEASTERLIES. WILL LEAVE THE NORTH-
NORTHWESTERLIES IN FOR NOW. WILL GO WITH A TEMPO FOR TSRA AFTER
19Z-20Z. NO CEILING ISSUES.
&&
.HYDROLOGY...
ISSUED AT 1039 AM MDT FRI MAY 15 2015
RIVER LEVELS ON THE SOUTH PLATTE WILL CONTINUE TO SLOWLY
RECEDE WITH THE EXCEPTION OF ITS COURSE THROUGH SEDGWICK. IT IS
STILL EXPECTED TO RISE IN SEDGWICK COUNTY INTO MID DAY SATURDAY
WITH THE CREST AT JULESBURG FORECAST TO BE BELOW FLOOD STAGE. IT
SHOULD START TO RECEDE AT JULESBURG BY SATURDAY AFTERNOON.
THE CACHE LA POUDRE RIVER IN WELD COUNTY IS JUST ABOVE FLOOD
STAGE AND THIS WILL CONTINUE INTO SATURDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RJK
SHORT TERM...GIMMESTAD
LONG TERM...COOPER
AVIATION...RJK
HYDROLOGY...RJK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
459 AM MDT FRI MAY 15 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 459 AM MDT FRI MAY 15 2015
COMPLEX SITUATION TODAY AS SOUTHERLY FLOW STRENGTHENS AHEAD OF
THE UPPER LOW OVER SOUTHERN NEVADA. BIGGEST QUESTION IS THE
POSITION OF LOW LEVEL FEATURES ON THE PLAINS THIS AFTERNOON AND
THE AMOUNT OF HEAT AND MOISTURE AVAILABLE FOR CONVECTION. SEVERAL
FACTORS ARE FAVORABLE FOR SEVERE WEATHER...MOST NOTABLY STRONG
SHEAR AND A PLUME OF MOISTURE PUSHING WESTWARD ON THE NORTH SIDE
OF A SURFACE LOW/TROUGH THAT WILL BE IN EASTERN COLORADO. IT IS
ALSO LOOKING LIKE THERE WILL BE ENOUGH DRY MID LEVEL AIR TO ALLOW
A FAIR AMOUNT OF SUN OVER NORTHEAST COLORADO TODAY...WHILE THE
WESTWARD EXTENT OF THE GOOD MOISTURE MAY BE A BIT MORE THAN
PREVIOUSLY EXPECTED. ALWAYS HARD TO SECOND GUESS JUST HOW MUCH
MIXING OUT OF THE MOISTURE THERE WILL BE...CERTAINLY WEST OF THE
DRY LINE THIS WILL HAPPEN...BUT ON THE NORTH SIDE OF THE LOW THE
PLUME OF MOISTURE WRAPPING AROUND WILL NOT MIX AS MUCH. BIGGEST
QUESTION IS PROBABLY THE SHARPNESS OF THE LOW/TROUGH FEATURE WHICH
IS OFTEN UNDERDONE IN THE MODELS. AT THIS HOUR THE HRRR IS SHOWING
A PLUME OF EAST WINDS HOLDING 50 DEGREE DEW POINTS AND CAPES
AROUND 2000 J/KG ALONG THE NORTHERN BORDER BACK AS FAR AS WELD
COUNTY. HOWEVER IT ALSO SCOURS OUT THE MOISTURE IN AREAS FURTHER
SOUTH...DRYING OUT WASHINGTON COUNTY BY MID AFTERNOON BEFORE THE
CONVECTION GETS GOING.
A NEGATIVE FACTOR MAY BE TOO MUCH SOUTHERLY WIND. THIS MAY HELP
DRY THINGS OUT AND PUSH THE BETTER MOISTURE TO THE NORTH...AND MAY
ALSO REDUCE THE SHEAR AND ESPECIALLY THE HELICITY IF THE WIND
PROFILE WINDS UP BEING PRETTY LINEAR. THERE SHOULD BE A SWEET SPOT
WITH THE LOW LEVEL WINDS BACKED TO EASTERLY...MOST LIKELY NEAR OUR
NORTHERN BORDER OR JUST INTO NEBRASKA. THIS AREA WOULD HAVE THE
BEST THREAT OF SEVERE WEATHER AND A DECENT TORNADO THREAT. WILL GO
WITH THIS IDEA AS THE MOST LIKELY SCENARIO...WITH STRONG STORMS
DEVELOPING IN THE MOISTURE ALONG THE DRY LINE AND/OR NORTH OF THE
LOW/TROUGH WHERE CAPES WILL BE 1500-2000 J/KG...THEN PROPAGATING
NORTH WITH THE SEVERE THREAT INCREASING NEAR OUR NORTHERN BORDER.
OTHER STORMS WILL FORM ON THE BACK EDGE OF THE DRY SLOT...NEAR THE
FRONT RANGE/CHEYENNE RIDGE BUT SHOULD BE WEAKER WITH CAPES OF 500
J/KG NEAR THE MOUNTAINS AND IMPROVING A BIT AS THEY MOVE EAST INTO
THE MOISTURE TONGUE. STILL COULD BE SOME SEVERE THREAT HERE AS
WELL...MAINLY IN NORTHERN WELD COUNTY. OF COURSE IF THE LOW WINDS
UP BEING BETTER DEFINED THERE WOULD BE A MUCH HIGHER THREAT OF
SEVERE WEATHER ON THE NORTH AND NORTHEAST SIDE OF THE LOW.
RAISED HIGHS A LITTLE EXPECTING MORE SUN...STILL A FEW DEGREES
BELOW GUIDANCE AND IF IT IS A LITTLE WARMER THAT WILL HELP AS
WELL. TRENDED POPS MORE TOWARD THE IDEA OF A GOOD BREAK IN THE DRY
SLOT MUCH OF TODAY...WITH STORMS MOVING IN FROM THE WEST AND
DEVELOPING IN THE NORTH AND EAST IN THE LATE AFTERNOON. BEST
COVERAGE PROBABLY IN THE EARLY EVENING ON THE PLAINS...BUT
INTESITY SHOULD BE LESS THEN. SOME CLOUDS AND WEAK SHOWERS HANG ON
OVERNIGHT WITH A LITTLE COOLING ALOFT AND OVERALL INCREASE IN
MOISTURE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM MDT FRI MAY 15 2015
OVERALL TREND IN THE FORECAST IS THE SAME. THE NEXT SYSTEM WILL
IMPACT THE CWA ON SATURDAY. THE BROAD BUT CLOSED UPPER TROUGH WILL
STRETCH FROM THE NORTHERN ROCKIES TO THE DESERT SOUTHWEST AT 12Z
SATURDAY...WITH A MODERATE TO STRONG SLY FLOW OVER EASTERN
COLORADO. WEAK TO MODERATE MID AND UPPER LEVEL QG ASCENT WILL
REMAIN OVER NORTHEAST COLORADO THROUGH THE DAY...WITH PLENTY OF
MOISTURE IN PLACE. MAIN ISSUE WILL BE WHERE THE SFC LOW SETS UP
AND AT THIS TIME IT APPEARS TO BE ALONG THE EASTERN BORDER. IF
THIS OCCURS...THEN THE STRONG/SEVERE THUNDERSTORMS WILL LIKELY BE
EAST OF COLORADO...BUT CANNOT RULE OUT ONE OR TWO REACHING SEVERE
LEVELS ALONG THE BORDER WHERE THE BEST VERTICAL SHEAR WILL BE
PRESENT. IN AND AROUND DENVER FORECAST CAPES IN THE AFTERNOON NOT
BAD...800-900 J/KG. MOISTURE AOA 700 MB IN THE AFTN...BUT DRIER IN
THE LOWER LEVELS. IN THE MOUNTAINS...NO HIGHLIGHTS BUT COULD SEE
UP TO 5 INCHES ABOVE 10 KT THROUGH THE DAY SATURDAY.
SATURDAY NIGHT INTO SUNDAY...THE QG ASCENT SHIFTS TO THE NORTH AND
EAST WITH INCREASING QG DESCENT OVER THE REGION. THE MID LEVEL
TROUGH AXIS SLIDES EASTWARD SATURDAY EVENING...WITH SUBSIDENCE
IN PLACE AS A SHORT WAVE RIDGE PUSHES INTO THE STATE THROUGH
SUNDAY. SOME LINGERING SHOWERS IN THE HIGH COUNTRY WEST OF THE
CONTINENTAL DIVIDE...BUT DOWNSLOPE IN AND NEAR THE FRONT RANGE
FOOTHILLS SHOULD NEGATE MUCH OF THE PCPN IN THE 03Z-06Z WINDOW.
FOR SUNDAY AFTERNOON...SHOWERS AND A FEW STORMS ARE PROGGED TO
DEVELOP AS MID LEVEL MOISTURE AND AFTN HEATING WILL OFFSET THE
INFLUENCE OF THE RIDGE.
SUNDAY NIGHT...A SURFACE HIGH IS PROGGED TO PUSH A COLD FRONT INTO
THE FRONT RANGE IN THE EVENING. LINGERING SHOWERS AND ISOLATED
THUNDERSTORMS WILL LINGER THROUGH SUNDAY EVENING. NOT MUCH IN THE
WAY OF PCPN FM 06Z-18Z MONDAY. THE UPPER RIDGE WILL SHIFT TO THE
EAST WITH THE FLOW ALOFT BECOMING SOUTHWESTERLY AHEAD OF THE NEXT
DEVELOPING TROUGH. MUCH OF THE SHOWER/TSTM ACTIVITY ON MONDAY
AFTN WILL OCCUR IN THE HIGH COUNTRY. MDLS STILL PEG ANOTHER GOOD
CHC OF PCPN FOR MUCH OF THE CWA LATE MONDAY NIGHT THROUGH TUESDAY
EVENING. A MOIST SOUTHERLY FLOW ALOFT AHEAD OF THIS TROUGH...
OVERRUNNING AND STATIONARY FRONTAL BOUNDARY SITTING ALONG THE
FRONT RANGE/PALMER DIVIDE. THIS BROAD TROUGH IS PROGGED TO LIFT
NORTHWARD TUESDAY NIGHT...BUT NOT ENOUGH TO DRY THE REGION OUT ON
WEDNESDAY/THURSDAY. BEST CHC OF SHOWERS/TSTMS THOSE DAYS APPEAR TO
BE FROM THE FRONT RANGE EASTWARD WHERE THE BEST MOISTURE WILL BE.
OVERALL TEMPERATURES WL REMAIN COOLER THAN NORMAL...COLDEST ON
SATURDAY AND THEN TUESDAY/WEDNESDAY OF NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 459 AM MDT FRI MAY 15 2015
VFR THROUGH TONIGHT. THERE WILL LIKELY BE A PERIOD OF GUSTY SOUTH
WINDS SHIFTING TO THE NORTH OR WEST DURING THE AFTERNOON...POSSIBLY
WITH SOME VARIABLE THUNDERSTORM OUTFLOW WINDS AS WELL. GUSTS AS
HIGH AS 40 KNOTS ARE POSSIBLE. ANY DIRECT THUNDERSTORM IMPACTS
SHOULD BE SHORT LIVED...BUT THE VARIABLE WINDS COULD LAST SEVERAL
HOURS.
&&
.HYDROLOGY...
ISSUED AT 459 AM MDT FRI MAY 15 2015
RIVER LEVELS ARE STILL COMING UP FROM JUST EAST OF STERLING TO
JULESBURG AND WILL RISE TO RIGHT AROUND FLOOD STAGE. THE CACHE LA
POUDRE RIVER IN WELD COUNTY IS JUST ABOVE FLOOD STAGE AND THIS
WILL CONTINUE INTO SATURDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GIMMESTAD
LONG TERM...COOPER
AVIATION...GIMMESTAD
HYDROLOGY...COOPER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
953 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST...LINGERING
NEARBY ON SUNDAY. A BACKDOOR COLD FRONT MOVES THROUGH SUNDAY
NIGHT. THE FRONT STALLS JUST SOUTHWEST OF THE REGION ON MONDAY
WITH HIGH PRESSURE BUILDING IN FROM THE NORTHEAST. THIS FRONT WILL
LIFT THROUGH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD
FRONT ON TUESDAY. HIGH PRESSURE IS THEN IN CONTROL INTO NEXT
WEEKEND...WITH THE EXCEPTION OF A WEAK COLD FRONTAL PASSAGE ON
FRIDAY
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDATED TEMPS/DEW POINTS. ADDED PATCHY FOG PER LATEST NARRE PROB
FOR VSBY LESS THAN 1 MILE. THIS MAKES SENSE DUE TO LINGERING LOW
LEVEL MOISTURE AND LIGHT WINDS...WITH GOOD COVERAGE FOR
SHOWERS/TSTMS.
MOST MESOSCALE MODELS...INCLUDING HRRR WHICH HAS BEEN GOOD FROM
RUN TO RUN...INDICATES CONVECTION CONTINUING THROUGH MIDNIGHT...
THEN DIMINISHING IN COVERAGE LATER TONIGHT. UPDATES THIS EVENING
BASED ON THESE TRENDS...AND ANALYSIS.
HIGH PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY
DOWNPOURS IN ANY STORM. MINOR URBAN FLOODING REMAINS A
POSSIBILITY...BUT SHOULD BE LESS LIKELY AS THE NIGHT PROGRESSES.
TEMPERATURES TONIGHT WILL BE MILD...IN THE 60S.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
DEEP UPPER LEVEL RIDGE BUILDS ACROSS THE EASTERN US ON SUNDAY.
SURFACE TROUGH LINGERS ACROSS THE AREA. WITH A DRIER AIR MASS IN
PLACE...EXPECTING MORE IN THE WAY OF SUNSHINE. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE LOWER AND MIDDLE 80S INLAND AND IN
THE NYC METRO...AND THE UPPER 70S CLOSER TO THE COAST. INSTABILITY
WILL BE ON THE INCREASE DURING THE DAY FROM THE CITY NORTH AND
WEST. AFTERNOON SEA BREEZES FURTHER EAST WILL LIMIT INSTABILITY.
LOW CHANCE POPS FORECAST ACROSS WESTERN ZONES IN THE BETTER
INSTABILITY AND WITH SURFACE TROUGH IN THE VICINITY. HOWEVER...THE
UPPER LEVEL RIDGE SHOULD LIMIT CONVECTIVE DEVELOPMENT. IF A STORM
DEVELOPS SUNDAY...IT MAY BE SLOW MOVING WITH WEAK LOW AND MIDDLE
LEVEL FLOW.
HIGH PRESSURE WILL BEGIN TO BUILD SW ACROSS THE AREA SUNDAY NIGHT
SENDING A BACK DOOR FRONT THROUGH. MODELS DIFFER IN THE TIMING OF
THE FRONT PASSAGE. CURRENT THINKING IS THAT THE FRONT WILL BEGIN
MOVING SOUTH ACROSS THE AREA SUNDAY EVENING. WITH THIS FRONT...AN
ISOLATED SHOWER OR STORM CANNOT BE RULED OUT. AS THE LOW LEVELS
COOL AND MOISTEN BEHIND THE FRONT...SOME FOG OR DRIZZLE ARE
POSSIBLE BY DAYBREAK MONDAY. LOW TEMPERATURES IN THE UPPER 50S AND
LOWER 60S ARE FORECAST SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. SLIGHT DIFFERENCES COME INTO PLAY WITH TIMING AND
AMPLITUDE OF A SHORTWAVE TROUGH MOVING THROUGH NEW ENGLAND ON
WED...ALTHOUGH SHOWER/TSTM ACTIVITY CURRENTLY LOOKS TO REMAIN TO OUR
N. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE WEEK WITH
ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING AROUND THE
BASE RESULTS IN AMPLIFICATION.
AT THE SFC...A FRONTAL BOUNDARY JUST TO THE SW OF THE AREA MON
MORNING...WILL REMAIN NEARLY STATIONARY AS SUBSIDENCE FROM HIGH PRES
TO THE NE NOSES IN. LOW LEVELS SATURATE EARLY IN THE MORNING AS A
RESULT WITH STRATUS EXPECTED AND WITH WEAK LIFT IN THE SATURATED
LAYER COULD CAUSE DRIZZLE. THERE IS ALSO A WEAK SHORTWAVE MOVING
THROUGH THE FLOW ALOFT WHICH COULD CAUSE A FEW AREAS OF RAIN. THE
LATTER WILL BE DETERMINED BY HOW MUCH DRY AIR IS IN PLACE ALOFT FROM
THE HIGH. HAVE ADDED SLIGHT CHANCE RAIN OR DRIZZLE FOR A FEW HOURS MON
MORNING AS A RESULT. WITH THE FRONT NEARBY THROUGH THE DAY...HAVE
MAINTAINED THE SLIGHT CHANCE POPS MAINLY FROM NYC AND AREAS N AND W FOR ANY
ACTIVITY THAT MAY DEVELOP IN THE AFTERNOON WITH WEAK AREAS OF VORTICITY
MOVING THROUGH THE MID-LEVELS. MON NIGHT MAY END UP BEING DRY FOR
THE MOST PART WITH MODEL TRENDS INDICATING THAT ANY ACTIVITY REMAINS
TO OUR SW...BUT MAINTAINED THE SLIGHT CHANCE TO LOW CHANCE POPS FOR THE TIME
BEING SINCE THERE IS UNCERTAINTY WITH HOW MUCH THE HIGH TO THE NE
BUILDS IN.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN THE
EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH PRESSURE
THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH THE END OF
THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER ASSOCIATED WITH A
WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
A SURFACE TROUGH CROSSES THE AREA TONIGHT. A BACKDOOR COLD FRONT
APPROACHES FROM THE NORTH SUNDAY MORNING...THEN BEGINS TO SINK
SOUTH INTO THE TRI-STATE SUNDAY AFTERNOON.
MAINLY VFR OUTSIDE OF CONVECTION THROUGH MIDNIGHT. COVERAGE AND
INTENSITY OF LINGERING CONVECTION DIMINISHES AFTER MIDNIGHT.
WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT
WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. CANNOT RULE
OUT IFR...OR EVEN VLIFR FOR THAT MATTER. HOWEVER...MVFR SHOULD
PREVAIL.
THEN A RETURN TO VFR SUNDAY...AFTER 14-15Z.
WINDS WILL REMAIN MAINLY LIGHT AND VARIABLE THROUGH MUCH OF THE
TAF PERIOD. SEA BREEZES ARE EXPECTED DURING THE AFTERNOON
SUNDAY...WITH SPEEDS 10 KTS OR LESS.
.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
.SUNDAY EVENING...MAINLY VFR. MVFR OR LOWER POSSIBLE IN ANY ISOLD
SHRA/TSTM.
.SUNDAY NIGHT-MONDAY EVENING...MVFR OR LOWER POSSIBLE IN
LOW CLOUDS/FOG. NE WINDS G15-20KT POSSIBLE DURING THE DAY ON
MONDAY.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
S WINDS 10-20 KT DIMINISH OVERNIGHT. BRIEF GUSTY WINDS ARE ALSO
POSSIBLE IN ANY SHOWER AND THUNDERSTORMS THAT MAY MOVE ACROSS THE
WATERS. FOG DEVELOPS.
OTHERWISE...SUB-SCA CONDITIONS ARE FORECAST FOR THE REMAINDER OF
THE FORECAST PERIOD WITH A RELATIVELY LIGHT FLOW PERSISTING ACROSS
THE AREA. GUSTS MAY REACH AROUND 20 KT LATE TUE NIGHT THROUGH
WED.
&&
.HYDROLOGY...
BASIN AVERAGE RAINFALL OF 1/4 INCH IS POSSIBLE THROUGH SUNDAY
MORNING WITH LOCALIZED HIGHER AMOUNTS IN A BAND OF SHOWERS AND
THUNDERSTORMS. MINOR URBAN FLOODING IS POSSIBLE IN ANY OF THE
HEAVIER SHOWERS/STORMS.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...24/DS
NEAR TERM...PW
SHORT TERM...DS
LONG TERM...24
AVIATION...PW
MARINE...24/DS/PW
HYDROLOGY...24/DS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
744 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT WILL BE SLOW TO PUSH NORTH OF THE AREA THROUGH THIS
EVENING...WHILE A TROUGH OF LOW PRESSURE APPROACHES FROM THE
WEST...LINGERING NEARBY ON SUNDAY. A BACKDOOR COLD FRONT MOVES
THROUGH SUNDAY NIGHT. THE FRONT STALLS JUST SOUTHWEST OF THE
REGION ON MONDAY WITH HIGH PRESSURE BUILDING IN FROM THE
NORTHEAST. THIS FRONT WILL LIFT THROUGH AS A WARM FRONT TUESDAY
MORNING...FOLLOWED BY A COLD FRONT ON TUESDAY. HIGH PRESSURE IS
THEN IN CONTROL INTO NEXT WEEKEND...WITH THE EXCEPTION OF A WEAK
COLD FRONTAL PASSAGE ON FRIDAY
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
MOST OF THE UPSTREAM CONVECTION WILL LIKELY WEAKEN THIS EVENING AS
IT TRACKS TOWARD THE CWA DUE TO S/SE FLOW AND ASSOCIATED MARINE
LAYER. HOWEVER...PRESENCE OF ELEVATED INSTABILITY...WAA AND UPPER
VORT OVER THE RIDGE...SHOWERS AND POSSIBLE TSTMS REMAINS A
POSSIBILITY THROUGH THE EARLY HOURS TONIGHT.
MOST MESOSCALE MODELS INCLUDING HRRR DO SHOW CONVECTION CONTINUING
THIS EVENING...THEN DIMINISHING IN COVERAGE LATER TONIGHT.
UPDATES THIS EVENING BASED ON THESE TRENDS...AND ANALYSIS.
HIGH PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY
DOWNPOURS IN ANY STORM. MINOR URBAN FLOODING IS A POSSIBILITY.
TEMPERATURES TONIGHT WILL BE MILD...IN THE 60S.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
DEEP UPPER LEVEL RIDGE BUILDS ACROSS THE EASTERN US ON SUNDAY.
SURFACE TROUGH LINGERS ACROSS THE AREA. WITH A DRIER AIR MASS IN
PLACE...EXPECTING MORE IN THE WAY OF SUNSHINE. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE LOWER AND MIDDLE 80S INLAND AND IN
THE NYC METRO...AND THE UPPER 70S CLOSER TO THE COAST. INSTABILITY
WILL BE ON THE INCREASE DURING THE DAY FROM THE CITY NORTH AND
WEST. AFTERNOON SEA BREEZES FURTHER EAST WILL LIMIT INSTABILITY.
LOW CHANCE POPS FORECAST ACROSS WESTERN ZONES IN THE BETTER
INSTABILITY AND WITH SURFACE TROUGH IN THE VICINITY. HOWEVER...THE
UPPER LEVEL RIDGE SHOULD LIMIT CONVECTIVE DEVELOPMENT. IF A STORM
DEVELOPS SUNDAY...IT MAY BE SLOW MOVING WITH WEAK LOW AND MIDDLE
LEVEL FLOW.
HIGH PRESSURE WILL BEGIN TO BUILD SW ACROSS THE AREA SUNDAY NIGHT
SENDING A BACK DOOR FRONT THROUGH. MODELS DIFFER IN THE TIMING OF
THE FRONT PASSAGE. CURRENT THINKING IS THAT THE FRONT WILL BEGIN
MOVING SOUTH ACROSS THE AREA SUNDAY EVENING. WITH THIS FRONT...AN
ISOLATED SHOWER OR STORM CANNOT BE RULED OUT. AS THE LOW LEVELS
COOL AND MOISTEN BEHIND THE FRONT...SOME FOG OR DRIZZLE ARE
POSSIBLE BY DAYBREAK MONDAY. LOW TEMPERATURES IN THE UPPER 50S AND
LOWER 60S ARE FORECAST SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. SLIGHT DIFFERENCES COME INTO PLAY WITH TIMING AND
AMPLITUDE OF A SHORTWAVE TROUGH MOVING THROUGH NEW ENGLAND ON
WED...ALTHOUGH SHOWER/TSTM ACTIVITY CURRENTLY LOOKS TO REMAIN TO OUR
N. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE WEEK WITH
ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING AROUND THE
BASE RESULTS IN AMPLIFICATION.
AT THE SFC...A FRONTAL BOUNDARY JUST TO THE SW OF THE AREA MON
MORNING...WILL REMAIN NEARLY STATIONARY AS SUBSIDENCE FROM HIGH PRES
TO THE NE NOSES IN. LOW LEVELS SATURATE EARLY IN THE MORNING AS A
RESULT WITH STRATUS EXPECTED AND WITH WEAK LIFT IN THE SATURATED
LAYER COULD CAUSE DRIZZLE. THERE IS ALSO A WEAK SHORTWAVE MOVING
THROUGH THE FLOW ALOFT WHICH COULD CAUSE A FEW AREAS OF RAIN. THE
LATTER WILL BE DETERMINED BY HOW MUCH DRY AIR IS IN PLACE ALOFT FROM
THE HIGH. HAVE ADDED SLIGHT CHANCE RAIN OR DRIZZLE FOR A FEW HOURS MON
MORNING AS A RESULT. WITH THE FRONT NEARBY THROUGH THE DAY...HAVE
MAINTAINED THE SLIGHT CHANCE POPS MAINLY FROM NYC AND AREAS N AND W FOR ANY
ACTIVITY THAT MAY DEVELOP IN THE AFTERNOON WITH WEAK AREAS OF VORTICITY
MOVING THROUGH THE MID-LEVELS. MON NIGHT MAY END UP BEING DRY FOR
THE MOST PART WITH MODEL TRENDS INDICATING THAT ANY ACTIVITY REMAINS
TO OUR SW...BUT MAINTAINED THE SLIGHT CHANCE TO LOW CHANCE POPS FOR THE TIME
BEING SINCE THERE IS UNCERTAINTY WITH HOW MUCH THE HIGH TO THE NE
BUILDS IN.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN THE
EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH PRESSURE
THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH THE END OF
THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER ASSOCIATED WITH A
WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
A SURFACE TROUGH CROSSES THE AREA TONIGHT. A BACKDOOR COLD FRONT
APPROACHES FROM THE NORTH SUNDAY MORNING...THEN BEGINS TO SINK
SOUTH INTO THE TRI-STATE SUNDAY AFTERNOON.
VFR OUTSIDE OF CONVECTION THROUGH THIS EVENING.
CONVECTION POSSIBLE THROUGH THE EVENING HOURS...THEN COVERAGE AND
INTENSITY DIMINISHES AFTER MIDNIGHT. BEST CHANCE WEST OF THE
HUDSON RIVER THIS EVENING.
WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT
WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. CANNOT RULE
OUT IFR...OR EVEN VLIFR FOR THAT MATTER. HOWEVER...MVFR SHOULD
PREVAIL.
THEN A RETURN TO VFR SUNDAY...AFTER 14-15Z.
WINDS WILL REMAIN MAINLY LIGHT AND VARIABLE THROUGH MUCH OF THE
TAF PERIOD. SEA BREEZES ARE EXPECTED DURING THE AFTERNOON
SUNDAY...WITH SPEEDS 10 KTS OR LESS.
.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
.SUNDAY EVENING...MAINLY VFR. MVFR OR LOWER POSSIBLE IN ANY ISOLD
SHRA/TSTM.
.SUNDAY NIGHT-MONDAY EVENING...MVFR OR LOWER POSSIBLE IN
LOW CLOUDS/FOG. NE WINDS G15-20KT POSSIBLE DURING THE DAY ON
MONDAY.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
S WINDS 10-20 KT DIMINISH OVERNIGHT. BRIEF GUSTY WINDS ARE ALSO
POSSIBLE IN ANY SHOWER AND THUNDERSTORMS THAT MAY MOVE ACROSS THE
WATERS.
OTHERWISE...SUB-SCA CONDITIONS ARE FORECAST FOR THE REMAINDER OF
THE FORECAST PERIOD WITH A RELATIVELY LIGHT FLOW PERSISTING ACROSS
THE AREA. GUSTS MAY REACH AROUND 20 KT LATE TUE NIGHT THROUGH
WED.
&&
.HYDROLOGY...
BASIN AVERAGE RAINFALL OF 1/4 INCH IS POSSIBLE THROUGH SUNDAY
MORNING WITH LOCALIZED HIGHER AMOUNTS IN A BAND OF SHOWERS AND
THUNDERSTORMS. MINOR URBAN FLOODING IS POSSIBLE IN ANY OF THE
HEAVIER SHOWERS/STORMS.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
659 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT MAY BRING A PERIOD OF RAIN TONIGHT INTO SATURDAY
MORNING AS THE FRONT MOVES ACROSS THE REGION. WARM AND MORE HUMID
WEATHER FOLLOWS SAT NIGHT INTO SUNDAY. THEN A BACKDOOR COLD FRONT
USHERS IN MUCH COOLER AIR INTO THE REGION SUNDAY NIGHT THROUGH EARLY
NEXT WEEK. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS TO THE
REGION MON NIGHT INTO TUE FOLLOWED BY DRY WEATHER MID TO LATE NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
7 PM UPDATE...
TWO SMALL VORTICES...ONE OVER THE CATSKILLS AND A SLIGHTLY MORE
VIGOROUS VORTEX ENTERING LAKE ONTARIO IS TRIGGERING SOME SHOWERS
ACROSS NY STATE. MUCH OF THIS ACTIVITY IS STRUGGLING TO REACH THE
GROUND GIVEN 20-30 DEG DEW PT DEPRESSIONS. THUS INITIALLY THIS
RAIN WILL DRY UP BEFORE REACHING SOUTHERN NEW ENGLAND. LATEST HRRR
AND RAP KEEP OUR AREA DRY THRU 03Z AND THEN SHOWERS ARRIVING
THEREAFTER FROM WEST TO EAST. PREVIOUS FORECAST CAPTURES THESE
DETAILS NICELY SO LITTLE IF ANY CHANGES WITH THIS UPDATE. EARLIER
DISCUSSION BELOW.
====================================================================
INTO THIS EVENING...
SCATTERED TO BROKEN CLOUD DECKS AS WE BEGIN TO COOL OFF TOWARDS
THE OVERNIGHT HOURS. SOUTHERLY FLOW CONTINUING AHEAD OF THE
APPROACHING WARM FRONT PRESENTLY ACROSS E NY AND CENTRAL PA. SEA-
BREEZES CONTINUING ALONG THE E-SHORE.
TONIGHT...
INITIAL INFLUX OF WARM-MOIST AIR UNDERGOING ISENTROPIC ASCENT WHILE
BEING FED REARWARD BY A NOTCH OF ENHANCED LOW-LEVEL FLOW VEERING
INTO N NEW ENGLAND. ITS ALONG THE NOSE OF WHICH...THE LEADING EDGE
BEING A LOW- TO MID-LEVEL WARM FRONT...THERE WILL BE THE FOCUS FOR
SHOWER ACTIVITY.
CONFIDENT OF ACTIVITY ACROSS THE W-HALF OF NEW ENGLAND JUST BASED ON
A CONSENSUS OF TIMING OF THE DEEP-LAYER MOIST PROFILE UNDERGOING LOW-
TO MID-LEVEL FORCING. E-HALF SHOULD REMAIN FOR THE MOST PART DRY ESP
WITHIN THE I-95 CORRIDOR / I-495 BELTWAY. ACTIVITY PUSHING WITH THE
MEAN-FLOW AROUND THE RIDGE IN PLACE. NOT ANTICIPATING ANY THUNDER.
EXPECTING LIGHT ACTIVITY WITH LACK OF DEEP-LAYER FORCING.
MILD CONDITIONS OVERNIGHT WITH LOWS AROUND THE UPPER-40S TO LOW-50S.
AM EXPECTING IT TO BE SLIGHTLY COOLER TO THE E.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SATURDAY...
LOOKING AT THE BIGGER PICTURE AND EVALUATING THE ENVIRONMENT: BEHIND
THE WARM-FRONT EXPECTING A PERIOD OF DRY AIR AND SUBSIDENCE ALLOWING
CLOUDS TO BECOME SCATTERED-BROKEN ACROSS S NEW ENGLAND. RETURN S/SW-
FLOW PUSHES THE BETTER AXES OF MOISTURE AND INSTABILITY INTO PA AND
UPSTATE NY. RIDGE ENHANCES IN RESPONSE TO INCREASING ANTI-CYCLONIC
FLOW OF THE WARM CONVEYOR BELT BETWEEN THE CENTRAL CONUS LOW AND
BERMUDA HIGH NETTING A SURFACE REFLECTION OF HIGH PRESSURE ACROSS
THE E GREAT LAKES REGION.
SO NOW WE NEED TO CONSIDER WHETHER OUR REGION DESTABILIZES AND WHAT
FORCING IS AVAILABLE. THE COMBINATION OF MID-LEVEL ENERGY AS SURFACE
HIGH PRESSURE EMERGES OVER THE E GREAT LAKES SUGGESTS SOME LEVEL OF
FORCING WILL BE AVAILABLE. THOUGH A CAP IN PLACE IT WOULD WEAKEN IF
SURFACE TEMPERATURES WARM INTO THE LOW-80S ALLOWING THE CAP TO BE
EASILY BROKEN WITH ANY FORCING. ACROSS OUR REGION THAT DOES NOT
LOOK TO BE THE CASE. MORNING WET WEATHER AND ABUNDANCE OF CLOUDS.
WE DO NOT LOOK TO WARM ENOUGH TO EXCEED CONVECTIVE TEMPERATURE
THRESHOLDS. THUS S NEW ENGLAND REMAINS CAPPED AND THERE IS VERY
LITTLE ELEVATED INSTABILITY WITHIN THE H85-7 TO BE NOTEWORTHY.
THEREFORE ANTICIPATE SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP
INITIALLY WELL TO THE W WITHIN THE BETTER ENVIRONMENT ACROSS
UPSTATE NY AND PA THAT WOULD SWEEP SE WITH THE STEERING-FLOW INTO
W NEW ENGLAND LATE. BUT NOTING THE DISCUSSION ABOVE AND WITH DAYTIME
HEATING DIMINISHING...FEEL ACTIVITY WOULD DISSIPATE INTO OUR REGION.
SO LIGHT SHOWERY WEATHER LINGERS FOR THE EARLY PORTION OF THE DAY
ACROSS THE E-HALF OF NEW ENGLAND. THE SUN POPS OUT BEHIND SCATTERED
TO BROKEN CLOUD DECKS BUT NOT ENOUGH TO DESTABILIZE THE ENVIRONMENT
AS TEMPERATURES WARM INTO THE 70S. SHOWER ACTIVITY IS EXPECTED LATE
FROM THE W ESPECIALLY ACROSS S- AND W-PORTIONS OF THE FORECAST AREA.
SATURDAY NIGHT...
SURFACE HIGH PRESSURE ACROSS THE E GREAT LAKES STRENGTHENS BENEATH
THE ENHANCING RIDGE ALOFT. THE LACK OF DAYTIME HEATING AND A LESS
CONVECTIVELY SUPPORTIVE ENVIRONMENT...A FEW SHOWERS MAY LINGER
MAINLY OVER THE S AND W...OTHERWISE REMAINING DRY. SCATTERED TO
BROKEN CLOUD DECKS LINGER...SO ANTICIPATING A MILD NIGHT OVERALL
WITH LIGHT WINDS OUT OF THE NW. LOWS AROUND THE MID- TO UPPER-50S.
GRADUAL CLEARING TOWARDS MORNING.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGHLIGHTS...
* DRY AND SUMMER-LIKE WARMTH SUNDAY AHEAD OF A BACKDOOR COLD FRONT
* MUCH COOLER SUN NIGHT AND MONDAY
* A PERIOD OF SHOWERS LIKELY MON NIGHT AND TUE FOLLOWED BY DRY AND
SEASONABLE WEATHER MID TO LATE NEXT WEEK
SYNOPTIC OVERVIEW AND GUIDANCE EVALUATION...
FAIRLY GOOD AGREEMENT ON THE LARGE SCALE FLOW THIS PERIOD FROM BOTH
ENSEMBLES /GEFS AND EPS/ AND DETERMINISTIC RUNS OF NAM/GFS AND ECMWF.
THUS A MODEL IS IN ORDER TO MINIMIZE MINOR TIMING AND AMPLITUDE
DIFFERENCES. VORTEX ENTERING WESTERN ONTARIO THIS AFTERNOON WILL
TRACK ACROSS SOUTHEAST CANADA THRU SUN AND THEN OVER NEW BRUNSWICK
AND INTO THE GULF OF ME SUN NIGHT AND MON. THIS WILL BE ACCOMPANIED
BY A BACKDOOR FRONT WHICH WILL USHER IN A MUCH COOLER MARITIME
AIRMASS INTO SOUTHERN NEW ENGLAND. AHEAD OF THIS FEATURE A WARM
SECTOR AIRMASS WILL RESIDE OVER THE REGION SUNDAY. THEN BY MON NIGHT
AND ESPECIALLY TUE JET ENERGY AND MOISTURE CURRENTLY OVER THE WEST
COAST ADVECTS NORTHEAST INTO NEW ENGLAND YIELDING OUR NEXT CHANCE OF
WIDESPREAD SHOWERS. THEN MAINLY DRY AND SEASONABLE WEATHER
OVERSPREADS SOUTHERN NEW ENGLAND MID TO LATE NEXT WEEK AS LONG WAVE
TROUGH SETS UP OVER SOUTHEAST CANADA.
DAILY SENSIBLE WEATHER....
SUNDAY...
WARM FRONT LIFTS NORTH ACROSS THE REGION SAT AFTN OR EVENING WITH
WARM SECTOR AIRMASS RESIDING OVER THE AREA SUNDAY. 2 METER MODEL
TEMPS SUPPORT 80-85 TEMPS AWAY FROM THE SHORE. WEAK PGRAD WILL
SUPPORT AFTERNOON COOLING SEABREEZES AT THE COAST ESPECIALLY WITH
WATER TEMPS ONLY IN THE L50S.
SUN NIGHT AND MON...
BY SUN EVENING AND ESPECIALLY SUN NGT A SIGNIFICANT BACKDOOR FRONT
WILL SWEEP ACROSS THE REGION FROM NE TO SW. COULD BE SOME SPOTTY
LIGHT DRIZZLE ESPECIALLY IN RI AND EASTERN MA WITH THIS FEATURE BUT
THE MAIN SENSIBLE WEATHER ITEM WILL BE THE RAPIDLY FALLING TEMPS
INTO THE 40S AND 50S SUN EVENING AND NIGHT. WATER TEMPS IN THE GULF
OF ME AND MAY BAY ONLY IN THE L50S AND WILL ACT AS A SNOWCOVER
ENHANCING THE COOLNESS OF THIS MARITIME AIRMASS. 1027 MB HIGH OVER
THE MARITIMES AND GULF OF ME MON WILL PRECLUDE COOL MARITIME AIRMASS
FROM WARMING MUCH MON WITH HIGHS ONLY 55 TO 60 IN IN EASTERN MA.
STRONG MAY SUNSHINE AND DISTANCE FROM THE OCEAN WILL SUPPORT TEMPS
IN THE L70S ACROSS THE CT RVR VLY/I-91 CORRIDOR OF CT AND MA.
MON NIGHT INTO TUE...
SHORT WAVE ENERGY AND PACIFIC MOISTURE CURRENTLY OVER THE WEST COAST
STATES WILL ARRIVE HERE MON NGT AND ESP TUE. ATTENDING COLD FRONT
WILL ACT ON 1.5"+ PWATS ALONG WITH MARGINAL ELEVATED INSTABILITY TO
YIELD A RISK OF WIDESPREAD SHOWERS LATE MON NIGHT THRU TUE NIGHT. IT
WILL REMAIN RELATIVELY COOL.
WED/THU/FRI...
EVOLVING LONG WAVE TROUGH OVER SOUTHEAST CANADA SUGGEST MAINLY DRY
WEATHER IN SOUTHERN NEW ENGLAND ALONG WITH MILD DAYS AND COOL
NIGHTS.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SATURDAY NIGHT/...
7 PM UPDATE...
NO MAJOR CHANGES FROM 18Z TAFS. ANY SHOWERS HOLD OFF UNTIL AFTER
03Z WEST AND AFTER 09Z EAST. EARLIER DISCUSSION BELOW.
=================================================================
TONIGHT...HIGH CONFIDENCE.
CIGS LOWERING TO LOW-END VFR. SCT -SHRA TOWARDS MORNING MAINLY
ACROSS THE W-HALF OF NEW ENGLAND. S-WINDS.
SATURDAY...MODERATE CONFIDENCE.
SCT-BKN LOW-END VFR CIGS. SCT -SHRA OVER THE E-HALF OF S NEW
ENGLAND DURING THE MORNING. -SHRA MOVING BACK INTO SW-PORTIONS OF
NEW ENGLAND WITH ISOLATED TSRA LATE. BREEZY S-WINDS. GUSTS UP TO
15 KTS ALONG THE SHORES.
SATURDAY NIGHT...LOW CONFIDENCE.
SCT-BKN LOW-END VFR / MVFR CIGS. LOW CONFIDENCE IFR AT THIS TIME.
FRONT DROPPING S THRU TERMINALS WITH SCT -SHRA. S-WINDS BACKING
OUT OF THE NW BY MORNING.
KBOS TAF...MODERATE CONFIDENCE IN TAF.
KBDL TAF...MODERATE CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SUN...HIGH CONFIDENCE. VFR. SEABREEZES LIKELY.
SUN NIGHT AND MON...MODERATE CONFIDENCE. WINDS BECOMING E/NE FROM E
TO W SUN NIGHT BEHIND A BACKDOOR FRONT WITH AREAS OF MVFR/IFR
DEVELOPING LATE SUN NIGHT INTO MON MORNING...THEN IMPROVING TO VFR
BUT LOW CLOUDS MAY WAIT UNTIL LATE MON TO LIFT.
TUE...MODERATE CONFIDENCE. AREAS OF MVFR/IFR DEVELOPING IN SCT TO
NUMEROUS SHOWERS AND POSSIBLY A TSTM.
WED...VFR AND DRY WEATHER LIKELY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SATURDAY NIGHT/...MODERATE CONFIDENCE.
INCREASING CHANCES OF SHOWERS WITH BREEZY S-WINDS BEGINNING
SATURDAY MORNING AND CONCLUDING INTO SUNDAY MORNING AS A WARM
FRONT LIFTS ACROSS THE REGION INITIALLY FOLLOWED BY A COLD FRONT
DROPPING S BEHIND WHICH WINDS SHIFT OUT OF THE NW. GUSTS HOLDING
BELOW 20 KTS AS WAVES REMAIN BELOW 5-FEET. LOW CONFIDENCE WITH
RESPECT TO VISIBILITY IMPACTS ON THE WATERS.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SUN...HIGH CONFIDENCE. RELATIVELY LIGHT WINDS AND SEAS. ONSHORE
WINDS DEVELOPING NEARSHORE WATERS SUNDAY AS SEABREEZES DEVELOP.
MON AND TUE...HIGH CONFIDENCE. E WINDS ON MON WILL GIVE WAY TO A
RETURN TO S WINDS TUE WITH ANOTHER ROUND OF SHOWERS AS A COLD FRONT
APPROACHES. CONDITIONS MAINLY BELOW SMALL CRAFT ADVISORY THRESHOLDS.
WED...FRONT MOVES OFFSHORE TUE NIGHT/EARLY WED WITH IMPROVING
CONDITIONS BEHIND THE FRONT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/SIPPRELL
NEAR TERM...NOCERA/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...NOCERA
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
336 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WILL BE OFFSHORE THROUGH SATURDAY. LOW PRESSURE FROM
THE UPPER MISSISSIPPI VALLEY WILL MOVE NORTHEASTWARD, WITH AN
ASSOCIATED WARM FRONT CROSSING OUR REGION TONIGHT. A COLD FRONT WILL
THEN SETTLE THROUGH OUR AREA LATE SUNDAY. THE NEXT AREA OF LOW
PRESSURE FROM THE ROCKIES SHOULD TRACK NORTHEASTWARD THROUGH THE
GREAT LAKES REGION, PULLING A COLD FRONT ACROSS OUR AREA TUESDAY.
HIGH PRESSURE WILL THEN GRADUALLY BUILD TOWARD OUR REGION WEDNESDAY
INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LOW PRESSURE LOCATED ALONG A FRONTAL BOUNDARY STRETCHING FROM THE
GREAT LAKES TO THE ROCKIES WILL CONTINUE MOVING NORTHWARD TONIGHT
WITH SOUTHERLY FLOW CONTINUING ACROSS THE REGION. EARLY ON, SOME
SCATTERED S-SSW WIND GUSTS FROM 15-20 MPH ARE POSSIBLE BUT THESE
WILL DIMINISH AS WE LOOSE MIXING CREATED BY DAYTIME HEATING. THESE
LOCALLY STRONGER WIND GUSTS COUPLED WITH LOCAL RH VALUES AROUND
30% MAY BE CLOSE TO RED FLAG CONDITIONS IN A FEW LOCATIONS. ATTM
THIS LOOKS SHORT LIVED AND ISOLATED, WILL NOT ISSUE A FIRE WEATHER
STATEMENT. MESOSCALE MODEL RUNS OF THE HRRR AND RAP SHOW THE
POTENTIAL FOR THE FORMATION OF A FEW LIGHT SHOWERS ALONG THE FRONT
OVERNIGHT. HOWEVER, WITH MOST MODELS OVERDOING DEW POINTS TODAY
DO NOT WANT TO COMMIT ANY HIGHER THAN SLIGHT CHANCE WITH THESE
POTENTIAL SPOTTY SHOWERS. PERIODS OF FAIR AND MOSTLY CLOUDY SKIES
WILL LIKELY ALTERNATE THROUGH THE NIGHT WITH A GENERAL INCREASE IN
CLOUDS BY MORNING. OVERNIGHT LOW TEMPERATURES LOOK TO END UP JUST
UNDER 60.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
THE FRONTAL BOUNDARY TO OUR NORTH WILL BE CLOSE ENOUGH AS
MOISTURE CONTINUES TO INCREASE TO INCLUDE A CHANCE OF AFTERNOON
THUNDERSTORMS SATURDAY AFTERNOON. ALSO, THE SET-UP ONCE AGAIN LOOKS
FAVORABLE FOR MIXING AND SOME SSW WIND GUSTS CLOSE TO 20 MPH IN THE
AFTERNOON. AREAS ACROSS NORTHERN NJ AND EASTERN PA HAVE THE HIGHEST
CHANCE OF SEEING AFTERNOON AND EVENING POP UP THUNDERSTORMS.
EVEN THOUGH WE HAVE BEEN DRY RECENTLY, PW VALUES WILL INCREASE TO
OVER 1.5 INCHES RESULTING IN HEAVY DOWNPOURS FROM ANY
THUNDERSTORMS. INSTABILITY LOOKS MARGINAL OVERALL, CHARACTERIZED
BY 1000 OR SO MODELED J/KG CAPE. HOWEVER, 0-6 KM BULK SHEAR IS
MODELED TO BE FAIRLY WEAK. OVERALL, INSTABILITY LOOKS SUFFICIENT
FOR SOME THUNDERSTORM DEVELOPMENT ACROSS THE REGION BUT STORM WILL
BE LIMITED WITH MORE OF A PULSE SET-UP LIKELY. AS USUAL, THE NAM
IS MOST AGGRESSIVE SHOWING STEEP LOW LEVEL LAPSE RATES AND SOME
MID-LEVEL DRY AIR WHICH MAY LEAD TO DOWNDRAFTS AND STRONGER WIND
GUSTS IN THE THUNDERSTORMS. THE GFS IS QUITE A BIT MORE STABLE
ATTM. CURRENT THINKING IS THAT SCATTERED STORMS WILL DEVELOP IN
THE AFTERNOON, MORE NUMEROUS CLOSER TO THE FRONT AND BE OF PULSE
NATURE. SPC HAS A MARGINAL RISK AS WELL FOR ANY SEVERE THREAT
TOMORROW AFTERNOON. 925 MB TEMPERATURES ALSO SUGGEST HIGH
TEMPERATURES FORECASTED ON MOST NUMERICAL GUIDANCE SETS LOOK TO
LOW. WILL GO HIGHER WITH FORECASTED HIGH TEMPERATURES, IN THE MID
80`S THAT ARE CONVECTION DEPENDENT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH IN THE WEST
THAT MIGRATES EAST-NORTHEASTWARD WITH TIME AND AN UPPER-LEVEL RIDGE
IN THE EAST. THE RIDGE REMAINS IN PLACE INTO TUESDAY BEFORE
FLATTENING OUT AS A TROUGH MOVES ACROSS THE MIDWEST AND GREAT LAKES.
THIS TROUGH SLIDES ACROSS THE NORTHEAST WEDNESDAY THEN THE FLOW
TURNS MORE ZONAL IN ITS WAKE. THE REGION REMAINS RATHER DRY AND
THERE ARE SOME OPPORTUNITIES FOR RAIN, GENERALLY CENTERED ON SUNDAY
AND LATE MONDAY AND TUESDAY. THE LATTER IS ASSOCIATED WITH A COLD
FRONT THAT IS FORECAST TO SWEEP ACROSS THE AREA TUESDAY. WE USED A
MODEL BLEND FOR SATURDAY NIGHT THROUGH MONDAY, THEN THE 12Z WPC
GUIDANCE OR SUPERBLEND THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE
FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES.
FOR SATURDAY NIGHT AND SUNDAY...THE RIDGE AXIS SHOULD BE APPROACHING
THE AREA SUNDAY MORNING. AN UPPER-LEVEL TROUGH AMPLIFIES ACROSS NEW
ENGLAND AND THIS WILL SEND A FRONTAL BOUNDARY OUR WAY LATE SUNDAY,
BASICALLY IN THE FORM OF A BACKDOOR FRONT AS HIGH PRESSURE BECOMES
ESTABLISHED NEAR THE CANADIAN MARITIMES. FIRST, LINGERING CONVECTION
MAY OCCUR SATURDAY EVENING THEN THIS SHOULD DISSIPATE AS THE NIGHT
WEARS ON. GIVEN THE SYNOPTIC SETUP ON SUNDAY, THE BETTER INSTABILITY
IS FORECAST TO BE PUSHED FARTHER INLAND AND NOT AS HIGH GIVEN SOME
WARMING ALOFT. THE CONVECTION THAT DOES FORM MAY TEND TO BE SLOW
MOVING AS THE FLOW WEAKENS WITH THE RIDGE AXIS NEARLY OVER OUR AREA
DURING SUNDAY, AND WITH PW VALUES OF 1.50-2.00 INCHES LOCALLY HEAVY
RAIN WILL BE POSSIBLE. THE RAIN WOULD BE WELCOMED SINCE THE REGION
CONTINUES TO BE RATHER DRY. ANY CONVECTION SHOULD LESSEN OR EVEN
DISSIPATE SUNDAY NIGHT, THEN A BACKDOOR FRONT MAKES ITS WAY ACROSS
THE AREA AS HIGH PRESSURE STRENGTHENS SOME AND EXTENDS INTO THE
NORTHERN MID ATLANTIC. THIS WILL RESULT IN COOLING FROM AN OCEAN
INFLUENCE SUNDAY NIGHT WITH PERHAPS SOME LOW CLOUDS DEVELOPING. WE
WENT A LITTLE ABOVE MOS GUIDANCE FOR HIGH TEMPERATURES ON SUNDAY AS
THE MODELS MAY BE OVERDOING THE CLOUD COVER.
FOR MONDAY AND TUESDAY...AN UPPER-LEVEL TROUGH IS FORECAST TO BE
LIFTING ACROSS THE GREAT LAKES REGION MONDAY AND ACROSS SOUTHEASTERN
CANADA TUESDAY. THIS WILL DRIVE A COLD FRONT EASTWARD, WHICH SHOULD
CLEAR OUR COAST DURING TUESDAY AS THE UPPER-LEVEL RIDGE FLATTENS
OUT. WE WILL START THE DAY MONDAY WITH AN ONSHORE FLOW BEFORE
SURFACE HIGH PRESSURE SHIFTS EAST AND THE FLOW STARTS TO VEER SOME
AHEAD OF A COLD FRONT. THE INSTABILITY AXIS TO OUR WEST SHOULD MOVE
EASTWARD AHEAD OF THE FRONT, HOWEVER THE INITIAL ONSHORE FLOW SHOULD
TEMPER THAT TO SOME EXTENT. THE PW VALUES ARE FORECAST TO REMAIN
ABOUT IN THE 1.50-2.00 INCH RANGE DESPITE SOME LOW-LEVEL
COOLING/STABILIZATION FROM THE ONSHORE FLOW. THERE MAY NOT BE A LOT
OF CONVECTION AROUND ON MONDAY BUT THIS WILL DEPEND ON THE EXTENSION
OF SURFACE HIGH PRESSURE INTO OUR AREA FROM THE NORTHEAST. WE
CONTINUED THE HIGHER POPS ACROSS THE WESTERN ZONES CLOSER TO THE
BETTER INSTABILITY. THE UPPER-LEVEL FEATURE IS FORECAST TO TRACK
WELL TO OUR NORTHWEST SO THIS MAY REMOVE OUR AREA FROM THE BEST
LARGE SCALE LIFT. THERE SHOULD BE MORE COVERAGE OF CONVECTION ON
TUESDAY AS A COLD FRONT ARRIVES WITH A MOIST ENVIRONMENT WITH SOME
INSTABILITY IN PLACE. THE MAIN DYNAMICS THOUGH MAY FOCUS MORE
FARTHER NORTH.
FOR WEDNESDAY THROUGH FRIDAY...AN UPPER-LEVEL TROUGH SETTLES ACROSS
THE NORTHEAST ESPECIALLY DURING WEDNESDAY BEFORE THE FLOW STARTS TO
TURN MORE ZONAL. AT THE SURFACE, HIGH PRESSURE IS FORECAST TO
GRADUALLY START BUILDING TOWARD OUR AREA DURING THIS TIME FRAME. A
PERIOD OF CAA OCCURS THOUGH FOLLOWING THE COLD FRONTAL PASSAGE
TUESDAY, AND THIS ALONG WITH A TIGHTENED PRESSURE GRADIENT MAY
RESULT IN BREEZY CONDITIONS WEDNESDAY INTO THURSDAY. THE UPPER-LEVEL
FLOW MAY SHARPEN SOME FRIDAY AND WITH A BOUNDARY STALLED WELL TO OUR
SOUTH SOME ENERGY MAY TRY AND TRACK ALONG IT. AS OF NOW, HIGH
PRESSURE IS FORECAST TO BE CLOSE ENOUGH TO OUR AREA THEREFORE WE
WENT WITH A DRY FORECAST ATTM.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS THROUGH MOST OF THE TAF PERIOD. SOME WIND GUSTS FROM
THE S OR SSW MAY APPROACH 15-20 KNOTS AT TIMES BEFORE DIMINISHING BY
00Z. ANOTHER WINDOW IS PRESENT FOR SSW WIND GUSTS AROUND 20 KNOTS
SATURDAY AFTERNOON. CEILINGS OVER 10,000 FEET THROUGH MOST OF TODAY
WILL LOWER SOME OVERNIGHT TO AROUND 5,000 FEET OVERNIGHT. SOME
SHOWERS AND PERHAPS THUNDERSTORMS ARE POSSIBLE TOMORROW AFTERNOON.
STILL TO EARLY TO HONE IN ON AN EXACT TIMEFRAME BROAD -SHRA GROUP
INCLUDED AT PHL ATTM.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...SOME SHOWERS AND THUNDERSTORMS AROUND
WITH POTENTIALLY TIMES OF MVFR/IFR, OTHERWISE VFR. THE GREATER
CHANCE SHOULD BE INLAND.
MONDAY AND TUESDAY...SOME LOW CLOUDS AND SHOWERS POSSIBLE TO START
MONDAY, OTHERWISE TIMES OF MVFR/IFR WITH SOME SHOWERS AND
THUNDERSTORMS ESPECIALLY DURING TUESDAY WITH A COLD FRONT.
WEDNESDAY...VFR OVERALL.
&&
.MARINE...
CONTINUED SOUTHERLY TO SOUTHWESTERLY WINDS UNDER SCA CRITERIA. WIND
GUSTS MAY PEAK AROUND 20 KNOTS SATURDAY AFTERNOON. SEAS WILL BE
BUILDING AS WELL, REACHING FOUR FEET BY SATURDAY AFTERNOON.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...A SOUTHWEST FLOW AHEAD OF A COLD FRONT
WILL BUILD THE SEAS SOME, HOWEVER THE CONDITIONS OVERALL ARE
ANTICIPATED TO BE BELOW SMALL CRAFT ADVISORY CRITERIA. THE WINDS
START TO BECOME ONSHORE SUNDAY NIGHT FROM NORTH TO SOUTH AS A
BACKDOOR FRONT MOVES THROUGH.
MONDAY AND TUESDAY...THE WINDS AND SEAS MAY NEAR ADVISORY CRITERIA
ON THE COASTAL WATERS AS THE FLOW IS ONSHORE MONDAY, THEN WEAKENS
SOME TUESDAY AS A COLD FRONT ARRIVES. DENSE FOG IS NOT ANTICIPATED
WITH THE ONSHORE FLOW ATTM.
WEDNESDAY...NORTHWESTERLY FLOW MAY BE A BIT GUSTY ESPECIALLY IN THE
MORNING, OTHERWISE CONDITIONS ARE ANTICIPATED TO BE BELOW ADVISORY
CRITERIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...GAINES
SHORT TERM...GAINES
LONG TERM...GORSE
AVIATION...GAINES/GORSE
MARINE...GAINES/GORSE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
304 PM EDT FRI MAY 15 2015
.SYNOPSIS...A HIGHLY AMPLIFIED UPPER LEVEL PATTERN CONTINUES THROUGH
THE U.S. WITH DEEP TROUGHING OVER THE WESTERN HALF OF THE CONUS. A
LITTLE CLOSER TO HOME OVER THE EASTERN HALF OF THE CONUS...
MID/UPPER LEVEL RIDGING EXTENDS NORTHWARD FROM CUBA OVER THE EASTERN
U.S. AND WILL PERSIST FOR THE NEXT COUPLE OF DAYS. THIS UPPER LEVEL
RIDGING IS THE PRIMARY SUPPORT FOR STRONG HIGH PRESSURE THAT IS
SITTING JUST OFF THE VIRGINIA COASTLINE. THIS BROAD AREA OF HIGH
PRESSURE RIDGING WEST SOUTHWEST OVER THE SOUTHEAST U.S. AND FLORIDA
WILL SHIFT SLIGHTLY TO THE EAST AND WILL BE THE MAIN WEATHER
INFLUENCE THROUGH THE WEEKEND. ALL MODELS ARE IN GOOD AGREEMENT WITH
THIS HIGH PRESSURE BLOCKING PATTERN TO CONTINUE OVER THE FLORIDA
PENINSULA.
.SHORT TERM (TONIGHT - SATURDAY)...THE LOCATION OF THE HIGH PRESSURE
CENTER WILL KEEP A PREDOMINANT EASTERLY WIND FLOW ACROSS THE
SUNSHINE STATE. THIS WIND FLOW WILL FAVOR THE EAST COAST SEA BREEZE
BEING THE DOMINANT TRIGGER FOR THUNDERSTORMS ACTIVITY. AS THE EAST
COAST SEA BREEZE BOUNDARY PUSHES WEST...THUNDERSTORMS WILL FIRE UP
OVER THE INTERIOR COUNTIES AND PROGRESSING TOWARD THE WEST COAST.
LATEST HRRR GUIDANCE HAS THE STRONGEST OF THESE STORMS INITIATING
BETWEEN 21-00Z AS THEY COLLIDE WITH THE WEST COAST SEA BREEZE. AS
WE HAVE SEEN OVER THE PAST COUPLE OF DAYS...SOME OF THESE STORMS
COULD BE STRONG PRODUCING HEAVY DOWNPOURS...GUSTY WINDS AND
FREQUENT LIGHTNING. TEMPERATURES ACROSS THE REGION ARE QUITE WARM
AND WILL TOP OUT IN THE UPPER 80S TO LOW 90S REGION WIDE.
&&
.MID/LONG TERM... THE SECOND HALF OF THE WEEKEND WILL FEATURE A
CONTINUATION OF THE SUMMERY PATTERN AS FAIRLY STRONG MID/UPPER LEVEL
RIDGING SITS OVER THE FL PENINSULA...WHILE AT THE SAME
TIME...ATLANTIC HIGH PRESSURE RIDGES BACK WESTWARD ALONG OR JUST
NORTH OF THE I-10 CORRIDOR. THE STACKED RIDGING ALOFT WILL KEEP OUR
TEMPERATURES ON THE WARM SIDE...WITH INLAND LOCATIONS APPROACHING OR
EXCEEDING 90S DEGREES. THE SURFACE HIGH PRESSURE RIDGE TO OUR NORTH
WILL PROVIDE A CONTINUED SYNOPTIC EASTERLY/SOUTHEASTERLY 1000-700MB
FLOW REGIME. AN EAST/SOUTHEAST SYNOPTIC FLOW REGIME FAVORS THE WEST
COAST SEA-BREEZE / I-75 CORRIDOR FOR LATE AFTERNOON/EVENING
CONVECTIVE DEVELOPMENT. EXPECT DECENT CHANCES SUNDAY AFTERNOON (40-
50% POPS) TO SEE A ROUND OF STORMS PROGRESSING EAST TO WEST ACROSS
THE PENINSULA...WITH SIMILAR TO PAST DAYS...THE CONVECTION LIKELY
PEAKING ALONG AND INSIDE THE I-75 CORRIDOR...WHERE LOW LEVEL
FOCUS/CONVERGENCE WILL BE MAXIMIZED. AS WITH ANY SUMMER
PATTERN...NOT EVERYONE IN THIS FAVORED AREA WILL RECEIVE
RAINFALL...BUT MOST EVERYONE SHOULD AT LEAST HAVE STORMS IN THE
VICINITY LATE IN THE DAY.
MONDAY STILL LOOKS TO BE SOMEWHAT OF A TRANSITION DAY AS THE SURFACE
RIDGE BOTH WEAKENS A BIT AND SETTLES SOUTHWARD. THEREAFTER...THE MID-
WEEK WILL CONTINUE THE TRANSITION WITH THE UPPER FLOW FLATTENING OUT
ALONG THE NORTHERN GULF COAST. TUESDAY SEES A WEAK/VARIABLE SYNOPTIC
FLOW LEVEL FLOW WHICH FAVORS SEA-BREEZE CONVERGENCE THROUGH THE
CENTER OF THE STATE IN THE LATE AFTERNOON. THEREFORE...ALTHOUGH A
FEW STORMS ARE POSSIBLE CLOSER TO THE COAST EARLY IN THE
AFTERNOON...THE BETTER RAIN CHANCES WILL EXIST INLAND FROM THE I-75
CORRIDOR DURING THE LATE AFTERNOON/EVENING HOURS.
FOR WEDNESDAY THROUGH FRIDAY...A WEAK FRONT SAGS DOWN TOWARD NORTH
FLORIDA. DO NOT GET TOO EXCITED. THIS FRONT IS NOT GOING TO PASS
THROUGH OUR REGION AND BRING US ANY COOLER OR DRIER WEATHER.
HOWEVER...IT WILL ACT TO TURN OUR LOCAL 1000-700MB SYNOPTIC FLOW
SHIFTS MORE TO THE NORTHWEST OR WEST. THIS FLOW REGIME FAVORS THE
FLORIDA EAST COAST FOR ORGANIZED LATE DAY CONVECTION. WILL HAVE THE
HIGHEST RAIN CHANCES WELL INLAND FOR THESE DAYS FINAL DAYS OF THE
FORECAST WEEK.
&&
.AVIATION...
OVERALL VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS. WINDS
WILL SHIFT TO THE WEST SOUTHWEST LATER THIS AFTERNOON AS THE SEA
BREEZE SETS UP. SCATTERED SHOWERS AND STORMS ARE POSSIBLE DURING
THE AFTERNOON HOURS SO WILL COVER THIS WITH VCTS STARTING BETWEEN
19-21Z. STORMS WILL DISSIPATE AFTER SUNSET AND THE WINDS WILL DIE
DOWN BECOMING LIGHT AND VARIABLE OVERNIGHT.
&&
.MARINE...OVERALL EASTERLY WIND FLOW WILL CONTINUE THROUGH THE
WEEKEND AS HIGH PRESSURE OFF THE VIRGINIA COAST RIDGES ACROSS THE
FLORIDA PENINSULA AND INTO THE GULF COAST WATERS. THE ONLY EXPECTED
CHANGE WILL BE ALONG THE COAST WHERE THE DAILY AFTERNOON SEA BREEZE
PATTERN SETS UP. WINDS WILL GENERALLY STAY BELOW 15 KNOTS AND SEAS
BELOW 3 FEET EXCEPT FOR DURING THE OVERNIGHT HOURS WHERE EASTERLY
SURGES WILL INCREASE WINDS TO SCEC ESPECIALLY OVER THE NORTHERN
COASTAL WATERS. THE GRADIENT WILL SLACKEN BY TUESDAY AS HIGH
PRESSURE MOVES INTO THE GULF OF MEXICO CAUSING A DECREASE IN WINDS
AND SEAS. THE WEATHER WILL REMAIN OVERALL DRY EXCEPT FOR LATE
AFTERNOON / EVENING THUNDERSTORMS THAT MAY MOVE FROM THE LAND OVER
THE COASTAL WATERS.
&&
.FIRE WEATHER...HIGH PRESSURE IN THE WESTERN ATLANTIC WILL KEEP AN
EAST TO SOUTHEAST WIND FLOW OVER THE FLORIDA PENINSULA THROUGH THE
WEEKEND. THIS WILL KEEP ABUNDANT LOW LEVEL MOISTURE OVER THE AREA
THAT WILL MAINTAIN RELATIVE HUMIDITY LEVELS ABOVE ANY CRITICAL
THRESHOLD. AFTERNOON RAIN SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
EACH AFTERNOON THIS WEEKEND WITH THE STRONGER STORMS OCCURRING OVER
THE WEST COAST FROM TAMPA BAY SOUTHWARD. NO SIGNIFICANT FOG IS
EXPECTED THROUGH THE NEXT COUPLE OF DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 89 73 89 / 20 60 40 50
FMY 72 92 72 91 / 30 50 30 50
GIF 72 90 71 91 / 10 50 20 40
SRQ 71 89 72 87 / 40 50 40 50
BKV 70 89 69 91 / 10 60 40 50
SPG 75 89 75 89 / 40 50 40 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...74/WYNN
MID/LONG TERM/DECISION SUPPORT...14/MROCZKA
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
635 AM EDT FRI MAY 15 2015
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH EARLY NEXT WEEK. A
COLD FRONT IS EXPECTED TO PUSH THROUGH THE REGION LATE TUESDAY
INTO WEDNESDAY AND POSSIBLY STALL NEAR OR SOUTH OF THE AREA. WEAK
HIGH PRESSURE IS EXPECTED TO RETURN THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FEW CHANGES WERE MADE WITH THE SUNRISE UPDATE BASED ON THE
LATEST HIGH RESOLUTION DATA...
* INTRODUCED SLIGHT CHANCE POPS FROM ROUGHLY WALTERBORO TO MONCKS
CORNER. BOTH THE RAP AND H3R HAVE COME IN LINE WITH THE EARLIER
RUNS OF THE NAM12 IN SHOWING ISOLATED SHOWERS/TSTMS FIRING IN
THIS AREA FOR A FEW HOURS THIS AFTERNOON WITHIN A BROAD
CONFLUENCE ZONE.
* GUIDANCE HAS PUSHED THE PRIMARY MOISTURE RETURN CHANNEL A BIT
FARTHER SOUTH SLIGHT CHANCE POPS WERE READJUSTED TO ONLY
INCLUDE AREAS FROM REIDSVILLE-LUDOWICI-DARIEN.
* NUDGED HIGH TEMPERATURES UP 1-2 DEGREES ACROSS FAR INTERIOR
SOUTHEAST GEORGIA.
DEEP LAYERED HIGH PRESSURE WILL REMAIN ANCHORED ATOP THE SOUTHEAST
U.S. AND DEEP SOUTH TODAY...ALTHOUGH SURFACE HIGH PRESSURE WILL
BEGIN TO MEANDER OFF THE MID-ATLANTIC COAST. THIS WILL ESTABLISH
A SOLID RETURN FLOW REGIME ACROSS THE DEEP SOUTH, ALTHOUGH MODELS
ARE SIMILAR IN KEEPING THE MAIN MOISTURE CONVEYOR DISPLACED JUST
TO THE SOUTH AND SOUTHWEST. ANY CHANCES FOR AN ISOLATED
SHOWER/TSTM WILL REMAIN CONFINED TO THE FAR SOUTHERN AND
SOUTHWESTERN PERIPHERY OF THE LOCAL FORECAST AREA; PRIMARY ALONG
AND SOUTHWEST OF A REIDSVILLE-DARIEN LINE. SLIGHT CHANCE POPS WILL
BE MAINTAINED IN THESE AREAS.
THE NAM12 HAS BEEN DEPICTING ISOLATED SHOWERS DEVELOPING ACROSS
THE CHARLESTON TRI-COUNTY AREA WITHIN WHAT APPEARS TO BE A BROAD
CONFLUENCE ZONE THAT A FORMS LATER THIS MORNING. IT IS UNCLEAR
WHETHER IS FEATURE WILL MATERIALIZE OR NOT, BUT THE LATEST H3R AND
RAP RUNS HAVE COME IN LINE WITH PREVIOUS NAM12 RUNS. INTRODUCED
SLIGHT CHANCE POPS FROM WALTERBORO-MONCKS CORNER TO COVER THIS.
THE DEEP ONSHORE FLOW WILL CURTAIL TEMPERATURES AGAIN TODAY.
HIGHS LOOK TO GENERALLY MAX OUT IN THE LOWER-MID 80S WITH MID-
UPPER 70S AT THE BEACHES. THIS IS SLIGHTLY BELOW NORMAL FOR MID-
MAY. THE VARIOUS 15/00Z MODELS SHOW SOME DEGREE OF CLEARING TAKING
PLACE LATER THIS AFTERNOON OR EARLY THIS EVENING, ESPECIALLY
ACROSS SOUTHEAST SOUTH CAROLINA. WILL ADJUST THE SKY FORECAST TO
SHOW A SLIGHTLY MORE OPTIMISTIC SKY CHARACTER DEVELOPING NORTH OF
THE SAVANNAH RIVER BY MID AFTERNOON TO TREND. CLOUDS LOOK TO HOLD
FOR MUCH OF THE DAY IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...DRY CONDITIONS WILL PREVAIL. ANY ISOLATED SHOWER/TSTM
ACTIVITY THAT DEVELOPS ACROSS THE FAR SOUTHERN AND SOUTHWESTERN
AREAS WILL DISSIPATE WITH THE LOSS OF INSOLATION. CLEARING WILL BE
ONGOING DURING THE EVENING HOURS WITH HIGH CLOUDS POSSIBLY
INCREASING AGAIN LATE AS THE MEAN UPPER LEVEL RIDGE AXIS SHIFTS
SLIGHTLY EAST. LOWS WILL RANGE FROM THE LOWER 60S INLAND WITH
UPPER 60S/NEAR 70 AT THE BEACHES.
SATURDAY AND SUNDAY...DEEP LAYERED RIDGING WILL PERSIST OVER THE
SOUTHEASTERN U.S. THROUGH THE WEEKEND. LACK OF SIGNIFICANT FORCING
AND A DECENT CAP NOTED IN MODEL SOUNDINGS WILL ALLOW FOR A MOSTLY
DRY FORECAST. THE EXCEPTION WOULD BE IN OUR FAR SOUTHERN ZONES IN
GEORGIA WHERE A BIT BETTER MOISTURE RESIDES. GIVEN THIS...HAVE
MAINTAINED A SLIVER OF SLIGHT CHANCE POPS IN THE FORECAST FOR THE
AFTERNOON/EVENING HOURS BOTH SATURDAY AND SUNDAY. HOWEVER
OVERALL...TRENDED POPS DOWNWARD AS LATEST GUIDANCE HAS COME IN
DRIER.
MONDAY...ATLANTIC HIGH PRESSURE WILL BEGIN TO WEAKEN AS A PRE-
FRONTAL TROUGH DEVELOPS AHEAD OF A COLD FRONT CROSSING THROUGH THE
OHIO AND MISSISSIPPI RIVER VALLEYS. INCREASING LOW LEVEL MOISTURE
WILL KEEP SLIGHT CHANCE/CHANCE FOR SHOWERS AND THUNDERSTORMS IN THE
AFTERNOON AND EVENING. WEAK SHEAR AND MARGINAL INSTABILITY WILL KEEP
OVERALL SEVERE POTENTIAL PRETTY LOW...ALTHOUGH CANNOT RULE OUT A
STRONGER PULSE STORM IF BOUNDARIES INTERACT.
TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. HIGHS
AWAY FROM THE COAST IN THE MID 80S SATURDAY WILL WARM TO THE UPPER
80S/AROUND 90 BY MONDAY. LOWS WILL BE QUITE MILD MAINLY IN THE MID
TO UPPER 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
MODELS ARE IN DECENT AGREEMENT IN THE LONG TERM PERIOD. A COLD
FRONT WILL APPROACH THE REGION TUESDAY...CROSSING THROUGH THE
LOCAL AREA LATE TUESDAY NIGHT INTO WEDNESDAY. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AHEAD OF AND ALONG THE FRONT. THE
FRONT MAY THEN STALL NEAR OR SOUTH OF THE AREA WHILE WEAK HIGH
PRESSURE BUILDS IN FROM THE NORTHWEST FOR LATE WEEK. TEMPERATURES
WILL REMAIN NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR. CIGS APPROACHING UPPER END OF MVFR THRESHOLDS ARE POSSIBLE
AFTER SUNRISE AT KCHS, ROUGHLY 13-16Z, BUT LOOK TO REMAIN VFR FOR
NOW.
EXTENDED AVIATION OUTLOOK...GENERALLY VFR CONDITIONS EXPECTED TO
PREVAIL THROUGH THE WEEKEND. FLIGHT RESTRICTIONS POSSIBLE WITHIN
AFTERNOON/EVENING THUNDERSTORMS EARLY NEXT WEEK.
&&
.MARINE...
TODAY...STILL SEEING SEAS OF 6 FT IN THE GEORGIA OFFSHORE WATERS
SO A SMALL CRAFT ADVISORY WILL REMAIN IN FORCE FOR THAT LEG UNTIL
11 AM. OTHERWISE, ONSHORE WINDS WILL PERSIST TODAY AS HIGH
PRESSURE ALONG THE MID-ATLANTIC COAST SHIFTS OFFSHORE IN THE
WESTERN ATLANTIC. EAST WINDS WILL GRADUALLY BECOME SOUTHEAST AS A
RESULT...BUT SPEEDS WILL GENERALLY REMAIN 15 KT OR LESS. SEAS WILL
SUBSIDE BY ABOUT A FOOT BY THIS AFTERNOON SETTLING INTO THE 2-3 FT
RANGE NEARSHORE WATERS AND A SOLID 4 FT OFFSHORE WATERS.
TONIGHT...SOUTHEAST WINDS OF 10-15 KT WILL PERSIST AS HIGH
PRESSURE SHIFTS EVEN FARTHER OFFSHORE. SEAS WILL REMAIN 2-3 FT
NEARSHORE WATERS WITH 3-4 FT OFFSHORE WATERS.
SATURDAY THROUGH WEDNESDAY...MARINE CONDITIONS WILL REMAIN RATHER
BENIGN OVER THE WEEKEND AS SURFACE HIGH PRESSURE REMAINS ANCHORED
OVER THE ATLANTIC. EAST/SOUTHEAST WINDS EXPECTED TO BE 15 KT OR LESS
WITH SEAS 2-4 FEET ON AVERAGE THROUGH SUNDAY. MONDAY...WINDS WILL
VEER MORE TO THE SOUTH/SOUTHWEST AS THE SURFACE HIGH GETS SUPPRESSED
SOUTH. A COLD FRONT WILL APPROACH THE REGION TUESDAY AND CROSS THE
WATERS LATE TUESDAY/EARLY WEDNESDAY. NORTHEAST WINDS WILL PICK UP
BEHIND THE FRONT WEDNESDAY HOWEVER CONDITIONS LOOK TO REMAIN UNDER
HEADLINE CRITERIA AT THIS TIME.
RIP CURRENTS...SECONDARY SWELL IS FORECAST TO INCREASE TO PERIODS
OF 8-9 SECONDS TODAY. THESE LONGER PERIODS WILL AFFECT THE SOUTH
CAROLINA BEACHES FIRST THE SPREAD DOWN THE COAST AS THE DAY
PROGRESSES. LONG PERIODS COMBINED WITH STRONG OUTGOING TIDES DUE
TO ALREADY ELEVATED TIDE LEVELS AND INCREASING INFLUENCES FROM
THE APPROACHING LUNAR PERIGEE WILL SUPPORT A RISK FOR MORE
FREQUENT RIP CURRENTS TODAY. A MODERATE RISK FOR RIP CURRENTS WILL
BE POSTED FOR ALL BEACHES THROUGH EARLY THIS EVENING.
&&
.TIDES/COASTAL FLOODING...
TIDE LEVELS WILL COME CLOSE TO CLOSE TO 7.0 FT MLLW IN THE
CHARLESTON HARBOR WITH HIGH TIDE EARLY THIS EVENING. A COASTAL
FLOOD ADVISORY MAY BE NEEDED FOR MAINLY THE SOUTH CAROLINA COASTAL
ZONES LATER TODAY IF CURRENT TIDE TRENDS CONTINUE.
ONSHORE WINDS COMBINED WITH INFLUENCES FROM THE LUNAR PERIGEE
WILL HELP PUSH TIDE LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL
TIDES THIS WEEKEND. SHALLOW COASTAL FLOODING WILL BE POSSIBLE
AROUND TIMES OF HIGH TIDE SATURDAY AND SUNDAY...ESPECIALLY ACROSS
SOUTH COASTAL SOUTH CAROLINA.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ374.
&&
$$
ST/ECT
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
620 AM EDT FRI MAY 15 2015
.SYNOPSIS...
DRY WEATHER THIS AFTERNOON UNDER HIGH PRESSURE AT THE SURFACE AND
ALOFT. THE CHANCE FOR RAIN WILL INCREASE SLIGHTLY THROUGH THE
WEEKEND AS MOISTURE RETURNS TO THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPPER RIDGE AXIS EXTENDING FROM THE WESTERN ATLANTIC NORTH
THROUGH THE CAROLINAS TO THE EASTERN GREAT LAKES. SURFACE HIGH
PRESSURE CENTERED OVER THE MID ATLANTIC COAST. ATMOSPHERIC
MOISTURE GRADIENT ACROSS THE REGION WITH DRIER AIR TO THE EAST AND
MORE MOISTURE TO THE WEST. UPPER IMPULSE CURRENTLY MOVING SLOWLY
EAST ACROSS THE WESTERN CAROLINAS AND GEORGIA. ..AND WILL MOVE
SLOWLY EAST THROUGH THE RIDGE AXIS ACROSS OUR FA LATER THIS
MORNING AND TO OUR EAST BY THIS AFTERNOON. A FEW LIGHT SHOWERS
POSSIBLE THIS MORNING AHEAD OF THE UPPER IMPULSE. LATER
TODAY...MODEL FOECAST SOUNDINGS INDICATE MID LEVEL CAPPING DUE TO
THE UPPER RIDGE AXIS AND GENERALLY LIMITED MOISTURE OVER MOST OF
THE FA. HOWEVER...DIURNAL HEATING MAY PROVIDE A CATALYST FOR SOME
ISOLATED TO WIDELY SCATTERED SHALLOW SHOWER ACTIVITY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BE OVER THE WESTERN ATLANTIC WITH
SOUTHEASTERLY FLOW PUSHING MOISTURE BACK INTO THE REGION. BEST
INSTABILITY WILL BE ACROSS THE UPSTATE. MAJORITY OF THE CWA WILL
REMAIN DRY THROUGH THE PERIOD. AFTERNOON HIGH TEMPERATURES WILL BE
IN THE MID 80S SATURDAY AND OVERNIGHT LOWS IN THE LOW TO MID 60S
EACH NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH A HIGHLY
AMPLIFIED PATTERN DOMINATING THE COUNTRY. THIS WILL KEEP AN UPPER
LEVEL RIDGE OVER THE EASTERN US WITH MOIST SOUTHERLY FLOW
PERSISTING OVER THE FORECAST AREA THROUGH THE MIDDLE OF THE WEEK.
EXPECTING MAINLY DIURNAL SHOWER/STORM ACTIVITY THROUGH A MAJORITY
OF THE PERIOD. A WEAK FRONTAL BOUNDARY WILL STRUGGLE TO CROSS THE
REGION ON WEDNESDAY WITH MODELS INDICTING THE FRONT SHEARING APART
AND STALLING OVER THE REGION FOR THURSDAY. WITH THE RUN TO RUN
CONSISTENCY OF THE LONG TERM MODELS CHANGES TO THE FORECAST HAVE
BEEN MINOR. TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY TO
ABOVE NORMAL.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS ACROSS THE CSRA...WITH MVFR VSBYS AT CAE/CUB. EXPECT
MVFR CIGS AND/OR VSBYS IN THE NEAR TERM. LATEST HRRR KEEPS LOWER
CIGS MAINLY NEAR THE CSRA IN THE NEAR TERM. DIURNAL HEATING
EXPECTED TO PROVIDE A RETURN TO VFR BY AFTERNOON. A FEW SHOWERS
WILL BE POSSIBLE BUT CHANCES NOT SUFFICIENT TO INCLUDE MENTION IN
THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN DIURNAL
CONVECTION THROUGH THE WEEKEND.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
410 AM EDT FRI MAY 15 2015
.SYNOPSIS...
DRY WEATHER THIS AFTERNOON UNDER HIGH PRESSURE AT THE SURFACE AND
ALOFT. THE CHANCE FOR RAIN WILL INCREASE SLIGHTLY THROUGH THE
WEEKEND AS MOISTURE RETURNS TO THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPPER RIDGE AXIS EXTENDING FROM THE WESTERN
ATLANTIC NORTH THROUGH THE CAROLINAS TO THE EASTERN GREAT LAKES.
SURFACE HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COAST.
ATMOSPHERIC MOISTURE GRADIENT ACROSS THE REGION WITH DRIER AIR TO
THE EAST AND MORE MOISTURE TO THE WEST. UPPER IMPULSE CURRENTLY
MOVING SLOWLY EAST ACROSS N AND CENT GA...WILL MOVE SLOWLY EAST
THROUGH THE RIDGE AXIS ACROSS OUR FA LATER THIS MORNING AND TO OUR
EAST BY THIS AFTERNOON. A FEW PATCHES OF LIGHT RAIN ACROSS
PORTIONS OF CENT GA MOVING EAST BUT GENERALLY APPEAR TO BE
WEAKENING. A FEW LIGHT SHOWERS POSSIBLE THIS MORNING AHEAD OF THE
UPPER IMPULSE. LATER TODAY...MODEL FORECAST SOUNDINGS INDICATE
MID LEVEL CAPPING DUE TO THE UPPER RIDGE AXIS AND GENERALLY
LIMITED MOISTURE OVER MOST OF THE FA. HOWEVER...DIURNAL HEATING
MAY PROVIDE A CATALYST FOR SOME ISOLATED TO WIDELY SCATTERED
SHALLOW SHOWER ACTIVITY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE
WILL BE OVER THE WESTERN ATLANTIC WITH SOUTHEASTERLY FLOW PUSHING
MOISTURE BACK INTO THE REGION. BEST INSTABILITY WILL BE ACROSS
THE UPSTATE. MAJORITY OF THE CWA WILL REMAIN DRY THROUGH THE
PERIOD. AFTERNOON HIGH TEMPERATURES WILL BE IN THE MID 80S
SATURDAY AND OVERNIGHT LOWS IN THE LOW TO MID 60S EACH NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH A HIGHLY
AMPLIFIED PATTERN DOMINATING THE COUNTRY. THIS WILL KEEP AN UPPER
LEVEL RIDGE OVER THE EASTERN US WITH MOIST SOUTHERLY FLOW
PERSISTING OVER THE FORECAST AREA THROUGH THE MIDDLE OF THE WEEK.
EXPECTING MAINLY DIURNAL SHOWER/STORM ACTIVITY THROUGH A MAJORITY
OF THE PERIOD. A WEAK FRONTAL BOUNDARY WILL STRUGGLE TO CROSS THE
REGION ON WEDNESDAY WITH MODELS INDICTING THE FRONT SHEARING APART
AND STALLING OVER THE REGION FOR THURSDAY. WITH THE RUN TO RUN
CONSISTENCY OF THE LONG TERM MODELS CHANGES TO THE FORECAST HAVE
BEEN MINOR. TEMPERATURES THROUGH THE LONG TERM WILL BE SLIGHTLY TO
ABOVE NORMAL.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
MVFR CIGS HAVE DEVELOPED ACROS THE CSRA. A LOW LEVEL E TO SE FLOW
EXPECTED TO RESULT IN MVFR CIGS...POSSIBLY IFR...THROUGH THIS
MORNING FOR PORTIONS OF THE REGION. LATEST HRRR KEEPS LOWER CIGS
MAINLY NEAR THE CSRA IN THE NEAR TERM. DIURNAL HEATING EXPECTED
TO PROVIDE A GRADUAL RETURN TO VFR BY AFTERNOON. A FEW SHOWERS
WILL BE POSSIBLE BUT CHANCES NOT SUFFICIENT TO INCLUDE MENTION IN
THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN DIURNAL
CONVECTION THROUGH THE WEEKEND.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BOISE ID
956 AM MDT FRI MAY 15 2015
.DISCUSSION...SHOWERS CONTINUE TO MOVE FROM SE TO NW ACROSS MUCH
OF THE CWA THIS MORNING. WE EXPECT MODERATE TO HEAVY RAIN THIS
AFTERNOON OVER THE WEST CENTRAL MTNS AND ALSO THE HIGHER TERRAIN
OF SE OREGON. OVERNIGHT...THE OBSERVING SITE NEAR ROME OREGON
(KREO) REPORTED OVER AN INCH OF RAIN. WE HAVE SLIGHTLY REDUCED
TEMPERATURES IN AREAS WHERE CLOUDS ARE EXPECTED TO BE THE MOST
CONSISTENT...AND SLIGHTLY RAISED THEM IN THE SOUTHEAST NEAR TWIN
FALLS AND JEROME WHERE SKIES WILL SEE SOME CLEARING. UPDATE OUT
SHORTLY.
&&
.AVIATION...MOSTLY VFR. BROKEN TO OVERCAST LOW VFR CLOUDS WITH
WIDESPREAD SHOWERS...ISOLATED THUNDERSTORMS THIS AFTERNOON. AREAS
OF MOUNTAIN OBSCURATION WITH LOCAL MVFR CONDITIONS IN HEAVIER
SHOWERS. SURFACE WINDS GENERALLY 12 KNOTS OR LESS WITH GUSTY WINDS
NEAR THUNDERSTORMS. WINDS ALOFT SOUTHEASTERLY AROUND 10 KNOTS UP
THROUGH 10K FEET MSL.
WEEKEND OUTLOOK...SHOWERS WITH AFTERNOON/EVENING THUNDERSTORMS WILL
CONTINUE THROUGH THE WEEKEND. CEILINGS EXPECTED TO REMAIN LOW VFR
ALONG WITH AREAS OF MOUNTAIN OBSCURATION. LOCAL MVFR CONDITIONS IN
HEAVIER SHOWERS.
&&
.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH SATURDAY...NUMEROUS SHOWERS ARE
LIFTING FROM THE SE TO THE NW ACROSS SW IDAHO AND SE
OREGON...GENERALLY IN AN ARC FROM THE STEENS MTN OREGON TO
FAIRFIELD IDAHO. SOUTH OF THIS AREA IS A BIT OF A DRY SLOT OVER NE
NV. HRRR LIFTS THE ARC TO THE NW THIS MORNING THEN SLOWS IT
TOWARDS NOON OVER BAKER COUNTY...AND BREAKS OUT MORE SHOWERS IN
THE DRY SLOT AS IT LIFTS ACROSS SW ID AND JORDAN VALLEY. CALIBRATED
SREF SHOWS GREATEST THUNDERSTORM THREAT ACROSS SW IDAHO THIS
AFTERNOON AND EVENING. PWAT IN THE 70-80TH PERCENTILE THROUGH THE
SHORT TERM AS UNSETTLED WEATHER WITH SHOWERS AND LATE DAY
THUNDERSTORMS CONTINUE OVER IDAHO ESPECIALLY. TEMPERATURES AVERAGE
AROUND 5 TO 10 DEGREES BELOW NORMAL IN THE SHORT TERM.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...MODELS CONTINUE TO
SHOW AN ACTIVE AND WET PATTERN AS A BROAD TROUGH CONTINUES TO
DOMINATE THE MID AND LONG TERM. A SERIES OF CLOSED LOWS ARE
EXPECTED TO MOVE SOUTH ALONG THE PACIFIC COAST CONTINUING THE
CHANCE OF SHOWERS AND AFTERNOON THUNDERSTORMS. HEAVIER BANDS OF
PRECIP AND BRIEF DRY PERIODS WILL EXIST...BUT POPS REFLECT AN
OVERALL UNSETTLED FORECAST. TEMPERATURES ARE EXPECTED TO REMAIN
WITHING 5 DEGREES OF NORMAL THROUGH THE PERIOD.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...SP
AVIATION.....JA
PREV SHORT TERM...VM
PREV LONG TERM....EP
AREA FORECAST DISCUSSION
NWS BOISE ID
331 AM MDT FRI MAY 15 2015
.SHORT TERM...TODAY THROUGH SATURDAY...NUMEROUS SHOWERS ARE
LIFTING FROM THE SE TO THE NW ACROSS SW IDAHO AND SE
OREGON...GENERALLY IN AN ARC FROM THE STEENS MTN OREGON TO
FAIRFIELD IDAHO. SOUTH OF THIS AREA IS A BIT OF A DRY SLOT OVER NE
NV. HRRR LIFTS THE ARC TO THE NW THIS MORNING THEN SLOWS IT
TOWARDS NOON OVER BAKER COUNTY...AND BREAKS OUT MORE SHOWERS IN
THE DRY SLOT AS IT LIFTS ACROSS SW ID AND JORDAN VALLEY. CALIBRATED
SREF SHOWS GREATEST THUNDERSTORM THREAT ACROSS SW IDAHO THIS
AFTERNOON AND EVENING. PWAT IN THE 70-80TH PERCENTILE THROUGH THE
SHORT TERM AS UNSETTLED WEATHER WITH SHOWERS AND LATE DAY
THUNDERSTORMS CONTINUE OVER IDAHO ESPECIALLY. TEMPERATURES AVERAGE
AROUND 5 TO 10 DEGREES BELOW NORMAL IN THE SHORT TERM.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...MODELS CONTINUE TO
SHOW AN ACTIVE AND WET PATTERN AS A BROAD TROUGH CONTINUES TO
DOMINATE THE MID AND LONG TERM. A SERIES OF CLOSED LOWS ARE
EXPECTED TO MOVE SOUTH ALONG THE PACIFIC COAST CONTINUING THE
CHANCE OF SHOWERS AND AFTERNOON THUNDERSTORMS. HEAVIER BANDS OF
PRECIP AND BRIEF DRY PERIODS WILL EXIST...BUT POPS REFLECT AN
OVERALL UNSETTLED FORECAST. TEMPERATURES ARE EXPECTED TO REMAIN
WITHING 5 DEGREES OF NORMAL THROUGH THE PERIOD.
&&
.AVIATION...MOSTLY VFR WITH BKN-OVC CLOUD COVER. SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH PERIOD...WITH MVFR POSSIBLE WITH
HEAVIER SHOWERS AND IN THE MTNS. SURFACE WINDS GENERALLY 12 KTS OR
LESS WITH GUSTS NEAR SHOWERS/THUNDERSTORMS. WINDS ALOFT NEAR 10K FT
MSL...NORTH 15-30 KTS.
WEEKEND OUTLOOK...SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE
THROUGH THE WEEKEND...ESPECIALLY IN THE AFTERNOONS. CEILINGS
EXPECTED TO REMAIN LOW VFR/MVFR DURING THIS TIME.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...VM
LONG TERM/AVIATION...EP
AREA FORECAST DISCUSSION
NWS LINCOLN IL
254 PM CDT FRI MAY 15 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 253 PM CDT FRI MAY 15 2015
THUNDERSTORMS HAVE BEEN ON THE INCREASE ACROSS MISSOURI THE LAST FEW
HOURS AS A SHORTWAVE LIFTS NORTHEAST...WITH MORE ISOLATED CONVECTION
IN THE SOUTHEASTERN CWA. NOT MUCH HOLDING THESE STORMS BACK AS
SURFACE BASED CAPE`S ARE OVER 2500 J/KG...BUT VERY LITTLE WIND SHEAR
ALOFT IS RESULTING IN A MORE PULSE-TYPE STORM ENVIRONMENT. HRRR
MODEL LIFTS THE BULK OF THESE STORMS THROUGH THE FORECAST AREA BY 8-
9 PM. MODEL GUIDANCE BEYOND THAT GETS A BIT MORE DISJOINTED...AS
SEVERAL OF THE HIGH-RESOLUTION MODELS PRETTY MUCH DRY THINGS OUT
ALTHOUGH THE HRRR TRIES TO BRING ANOTHER LOBE THROUGH LATE EVENING.
HAVE LARGELY GONE WITH 30-40% POP`S THROUGH THE NIGHT IN MOST AREAS
EXCEPT FOR SOME HIGHER VALUES EARLY EVENING ACROSS THE SOUTHWEST CWA
WITH THE CURRENT ACTIVITY. HOURLY TEMPERATURES WILL BE TRICKY AS THE
STORMS WILL CAUSE SOME TEMPORARY COOLDOWNS...BUT OVERALL LOWS IN THE
MID 60S REQUIRED LITTLE CHANGE FROM THE PREVIOUS FORECAST.
&&
.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 253 PM CDT FRI MAY 15 2015
- KCHI 150802
WRKAFD
MORNING UPPER AIR AND MOISTURE CHANNEL IMAGERY SHOWS CLOSED UPPER
LOW IN ROCKIES WITH A MAIN VORT LOBE IN THE CENTRAL PLAINS,
ADVECTIVING DEEP MOISTURE PLUME NORTHWARD FROM TX INTO THE CENTRAL
MIDWEST. SURFACE DATA SHOWS VERY MOIST AIRMASS OVER IL REGION, WITH
2500 CAPE, DEW POINTS APPROACHING 70 AND TEMPS IN LOWER 80S. WITH
THE PROGGED CONTINUING OF THE MOISTURE FETCH NORTHWARD TONIGHT
THROUGH MUCH OF STATE SATURDAY, THERE WILL BE LITTLE CHANGE IN
RESULT FOR THE START OF WEEKEND.
EXPECT SCATTERED STORMS TONIGHT INTO DAY SATURDAY, BUT WILL LIMITED
SHEAR AVAILABLE, SEVERE POTENTIAL WILL BE ON THE LOCALLIZED SCALE.
BY SUNDAY THOUGH, PATTERN CHANGES AS THE UPPER LOW STARTS TO MOVE
NORTHEAST SATURDAY NIGHT. BY SUNDAY IT REACHES THE DAKOTAS AND
ANOTHER WAVE ROTATES EAST AROUND THE LOW INTO THE PLAINS. THIS WILL
GET THE FRONT MOVING EAST, PROVIDING AN INCREASE IN SHEAR AND
CONVERGENCE INTO THE IL REGION ON SUNDAY. WITH LITTLE CHANGE IN
MOISTURE, THE AFTERNOON AND EVENING WILL BE THE BEST CHANCES FOR
ORGANIZED SEVERE. AMOUNT OF SHEAR AND STRENGTH OF UPPER LEVEL
SUPPORT IN THE AREA STILL A LITTLE UNCERTAIN, BUT A SLIGHT RISK OF
SEVERE STILL IS SUPPORTABLE.
DRYING SUNDAY NIGHT AS UPPER WAVE MOVES EAST WILL CLEAR PCPN CHANCES
FOR MONDAY. COOLER AIR MOVES IN AND WILL SOME WEAK RIDGING ALOFT,
QUITE WEATHER IS RULE EARLY IN THE WEEK. A WEAK UPPER LEVEL WAVE
MOVES OUT OF STILL STAGNATE UPPER TROUGH IN THE WESTERN ROCKES,
WHICH WILL BRING CHANCE OF PCPN WED TO THURS, BUT WITH DRIER, MORE
STABLE AIR IN AREA, SLIGHT CHANCE POPS ARE THE RESULT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1237 PM CDT FRI MAY 15 2015
BROKEN MVFR CEILINGS BECOME A BIT MORE WIDESPREAD AS CLEAR SLOT
IN THE KSPI-KCMI CORRIDOR BEGAN SEEING DIURNAL DEVELOPMENT OVER
THE LAST COUPLE HOURS. AM EXPECTING THIS TO LIFT UPWARD ABOVE 3000
FEET EARLY THIS AFTERNOON. MORE PERSISTENT LOWER CEILINGS WHICH
HAD PLAGUED KPIA MOST OF THE MORNING ARE FINALLY LIFTING UPWARD
THOUGH. CONVECTION ACROSS MISSOURI IS TRACKING NORTHEAST AND IS
PROJECTED TO START AFFECTING KSPI-KDEC AROUND 20-21Z AND
KPIA/KBMI TOWARD 23Z. HAVE ADDED VCTS AT ALL SITES AND WILL
MONITOR FOR AMENDING TO ADD PREVAILING/TEMPO GROUPS OF LOWER
CONDITIONS AS THE STORMS BECOME MORE ORGANIZED. SEVERAL OF THE
HIGH-RESOLUTION MODELS LIFT MUCH OF THE CONVECTION OUT OF THE
CENTRAL ILLINOIS TAF SITES BY MID EVENING OR SO. HAVE ADDED SOME
MORE MVFR CEILINGS OVER EAST CENTRAL ILLINOIS OVERNIGHT BASED ON
NAM MODEL SOUNDINGS. THESE SHOULD LIFT BY MID MORNING SATURDAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...GOETSCH
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1238 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1025 AM CDT FRI MAY 15 2015
CLUSTERS OF SHOWERS/STORMS ACROSS THE SOUTHEAST THIRD OF THE CWA
HAVE LARGELY EXITED THE AREA...HOWEVER REGIONAL RADAR SHOWS SOME
WIDELY SCATTERED SHOWERS EXTENDING SOUTHWEST FROM THERE TOWARD THE
SOUTHERN ST. LOUIS METRO ALONG THE EDGE OF A NARROW CLEAR SLOT.
MAIN FRONTAL BOUNDARY CONTINUES TO LIFT NORTHWARD AND MOST OF THE
CWA NOW HAS DEW POINTS WELL INTO THE 60S. SOME LOW CLOUDS HAVE
BEEN PERSISTING ACROSS THE ILLINOIS RIVER VALLEY...ALTHOUGH
CEILINGS SHOULD RISE OVER THE NEXT COUPLE HOURS.
MAIN CHALLENGE FOR TODAY IS WITH TIMING OF REDEVELOPMENT. UPPER
WAVE ACROSS THE CENTRAL PLAINS EXPECTED TO TRACK INTO WESTERN
MISSOURI LATER TODAY...WITH THE NAM AND HRRR BOTH DEVELOPING
CONVECTION BY MID AFTERNOON. HOWEVER...THE HRRR ALSO LIFTS
CONVECTION CURRENTLY IN SOUTHERN MISSOURI/NORTHERN ARKANSAS
NORTHWARD AND BRINGS IT NEAR A JACKSONVILLE TO EFFINGHAM LINE BY
MID AFTERNOON. THE PREVIOUS AFTERNOON POP GRIDS HAD THAT
PARTICULAR SCENARIO ALREADY IN PLACE...AND RECENT UPDATES
CONTINUED THAT GENERAL TREND EXCEPT TO INCREASE THE POP`S A BIT
MID/LATE AFTERNOON.
&&
.SHORT TERM...(TODAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
07Z/2AM SURFACE ANALYSIS SHOWS A 1012MB LOW OVER WESTERN
WISCONSIN...WITH A WARM FRONT ARCING SOUTHEASTWARD INTO NORTH-
CENTRAL ILLINOIS. SURFACE WINDS AT ALL KILX OB SITES HAVE VEERED TO
THE S/SW...SO THINK FRONT IS NOW JUST NORTH OF THE AREA ALONG A
MOLINE TO KANKAKEE LINE. WIDELY SCATTERED SHOWERS CONTINUE SOUTH OF
THE FRONT...ALTHOUGH RADAR IS SHOWING A DISTINCT DIMINISHING TREND.
WITH WARM FRONT LIFTING FURTHER NORTHWARD THIS MORNING...FORCING FOR
ADDITIONAL CONVECTION WILL BE WEAK. AS A RESULT...THINK ONLY
ISOLATED SHOWERS/THUNDER WILL BE PRESENT ACROSS THE AREA THROUGH
MIDDAY. AS THE DAY PROGRESSES...A WEAK SHORT-WAVE TROUGH NOTED ON
LATEST WATER VAPOR IMAGERY OVER TEXAS WILL APPROACH FROM THE
SOUTHWEST...PROVIDING ENHANCED LIFT AND GREATER AREAL COVERAGE OF
CONVECTION. 4KM WRF-NMM SHOWS SCATTERED SHOWERS/THUNDER DEVELOPING
IN ADVANCE OF THE WAVE ACROSS MISSOURI BY EARLY AFTERNOON...THEN
SPREADING ACROSS THE SOUTHERN HALF OF THE CWA BY MID TO LATE
AFTERNOON. HAVE FASHIONED THE POPS ACCORDINGLY...FEATURING ONLY
ISOLATED SHOWERS/THUNDER ALONG AND NORTH OF I-74...WITH SCATTERED
WORDING FURTHER SOUTH ACROSS THE REMAINDER OF THE AREA. WILL BE A
WARM AND HUMID DAY...WITH AFTERNOON HIGH TEMPERATURES TOPPING OUT IN
THE UPPER 70S AND LOWER 80S.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
TEXAS WAVE WILL TRACK THROUGH THE AREA TONIGHT...TRIGGERING WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS. DESPITE MODEST LIFT ASSOCIATED
WITH THIS FEATURE...WILL ONLY CARRY LOW CHANCE POPS AS DAYTIME
INSTABILITY WANES. ANOTHER SHORT-WAVE EMBEDDED WITHIN THE DEEP
SOUTHWESTERLY FLOW PATTERN WILL APPROACH FROM THE SOUTHWEST ON
SATURDAY...WITH MODELS DISAGREEING ON HOW MUCH PRECIP IT WILL
GENERATE. MOST MODELS HAVE BEEN SHOWING THIS FEATURE TRACKING
TOWARD THE OHIO RIVER VALLEY FOR THE PAST FEW RUNS...WHICH WOULD
MEAN THE STRONGEST LIFT AND HIGHEST RAIN CHANCES WOULD BE FOCUSED
ACROSS THE SOUTHEAST CWA. LATEST NAM HAS STRAYED FROM THAT THINKING
AND NOW SPREADS QUITE A BIT OF PRECIP ACROSS THE ENTIRE AREA. HAVE
REJECTED THIS SOLUTION IN FAVOR OF THE CONSENSUS...WHICH STILL KEEPS
THE MAIN INFLUENCE OF THE WAVE FURTHER SOUTHEAST. AS A
RESULT...WILL FOCUS LIKELY POPS ALONG/SOUTH OF I-70 ON SATURDAY WITH
CHANCE POPS FURTHER NORTH AND WEST.
WESTERN CONUS UPPER LOW IS STILL EXPECTED TO TRACK INTO THE NORTHERN
PLAINS BY SUNDAY...WITH TRAILING COLD FRONT TRIGGERING WIDESPREAD
SHOWERS AND THUNDERSTORMS. MOST MODELS INDICATE STRONG/SEVERE
CONVECTION ACROSS NEBRASKA/KANSAS/OKLAHOMA SATURDAY AFTERNOON AND
EVENING...WITH STORMS TRACKING EASTWARD AND WEAKENING AS THEY
APPROACH THE MISSISSIPPI RIVER OVERNIGHT. THINK REMNANT
SHOWERS/THUNDERSTORMS WILL SPILL INTO WEST-CENTRAL ILLINOIS SUNDAY
MORNING BEFORE DISSIPATING TOWARD MIDDAY. ADDITIONAL DEVELOPMENT
WILL BE LIKELY LATER IN THE DAY...HOWEVER DEGREE OF
DESTABILIZATION IS IN QUESTION DUE TO CLOUD DEBRIS FROM THE
MORNING PRECIP. WITH SURFACE DEWPOINTS WELL INTO THE 60S...ANY
AMOUNT OF HEATING WILL EASILY CREATE SBCAPES OF 1500 TO 2500J/KG.
IN ADDITION...0-6KM BULK SHEAR WILL INCREASE TO OVER 40KT AS THE
WESTERN TROUGH APPROACHES. STILL DIFFICULT TO PIN DOWN EXACT
SEVERE WEATHER THREAT...HOWEVER THINK THUNDERSTORMS WILL BE LIKELY
WITH A FEW POSSIBLY BECOMING SEVERE DURING THE AFTERNOON AND
EVENING. MAIN THREATS WOULD BE DAMAGING WIND GUSTS AND LARGE
HAIL.
WHILE ACTUAL COLD FRONT REMAINS WELL TO THE WEST...MOST
MODELS SUGGEST THE MAIN BAND OF ACTIVE CONVECTION WILL SHIFT E/SE
INTO THE OHIO RIVER VALLEY SUNDAY NIGHT. WILL THEREFORE CONFINE
CHANCE POPS TO AREAS EAST OF THE I-55 CORRIDOR. FRONT WILL PUSH
THROUGH THE AREA ON MONDAY...WITH POTENTIAL RE-DEVELOPMENT OF
STORMS ALONG THE BOUNDARY LATER IN THE DAY. WILL HANG ON TO LOW
CHANCE POPS ACROSS THE FAR E/SE ACCORDINGLY...HOWEVER IT APPEARS
GREATEST CHANCE FOR ADDITIONAL THUNDER WILL BE FURTHER EAST INTO
INDIANA AND KENTUCKY.
ONCE THE FRONT PASSES...UNSEASONABLY STRONG CANADIAN HIGH PRESSURE
WILL SETTLE INTO THE REGION NEXT WEEK. WITH 850MB TEMPS PROGGED TO
DROP INTO THE SINGLE DIGITS...CORRESPONDING HIGHS WILL FALL BACK
INTO THE 60S AND LOWS WILL DIP INTO THE 40S TUESDAY THROUGH
THURSDAY. A WEAK UPPER-LEVEL WAVE WILL TRY TO APPROACH FROM THE
WEST BY MID-WEEK...BUT THINK IT WILL HAVE LITTLE IMPACT ON THE
WEATHER DUE TO THE COOL/DRY AIRMASS ACROSS THE REGION. GFS IS
AGGRESSIVELY PUSHING SHOWERS INTO THE AREA WEDNESDAY/WEDNESDAY
NIGHT...BUT AM GOING WITH A DRY FORECAST AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1237 PM CDT FRI MAY 15 2015
BROKEN MVFR CEILINGS BECOME A BIT MORE WIDESPREAD AS CLEAR SLOT
IN THE KSPI-KCMI CORRIDOR BEGAN SEEING DIURNAL DEVELOPMENT OVER
THE LAST COUPLE HOURS. AM EXPECTING THIS TO LIFT UPWARD ABOVE 3000
FEET EARLY THIS AFTERNOON. MORE PERSISTENT LOWER CEILINGS WHICH
HAD PLAGUED KPIA MOST OF THE MORNING ARE FINALLY LIFTING UPWARD
THOUGH. CONVECTION ACROSS MISSOURI IS TRACKING NORTHEAST AND IS
PROJECTED TO START AFFECTING KSPI-KDEC AROUND 20-21Z AND
KPIA/KBMI TOWARD 23Z. HAVE ADDED VCTS AT ALL SITES AND WILL
MONITOR FOR AMENDING TO ADD PREVAILING/TEMPO GROUPS OF LOWER
CONDITIONS AS THE STORMS BECOME MORE ORGANIZED. SEVERAL OF THE
HIGH-RESOLUTION MODELS LIFT MUCH OF THE CONVECTION OUT OF THE
CENTRAL ILLINOIS TAF SITES BY MID EVENING OR SO. HAVE ADDED SOME
MORE MVFR CEILINGS OVER EAST CENTRAL ILLINOIS OVERNIGHT BASED ON
NAM MODEL SOUNDINGS. THESE SHOULD LIFT BY MID MORNING SATURDAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1026 AM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1025 AM CDT FRI MAY 15 2015
CLUSTERS OF SHOWERS/STORMS ACROSS THE SOUTHEAST THIRD OF THE CWA
HAVE LARGELY EXITED THE AREA...HOWEVER REGIONAL RADAR SHOWS SOME
WIDELY SCATTERED SHOWERS EXTENDING SOUTHWEST FROM THERE TOWARD THE
SOUTHERN ST. LOUIS METRO ALONG THE EDGE OF A NARROW CLEAR SLOT.
MAIN FRONTAL BOUNDARY CONTINUES TO LIFT NORTHWARD AND MOST OF THE
CWA NOW HAS DEW POINTS WELL INTO THE 60S. SOME LOW CLOUDS HAVE
BEEN PERSISTING ACROSS THE ILLINOIS RIVER VALLEY...ALTHOUGH
CEILINGS SHOULD RISE OVER THE NEXT COUPLE HOURS.
MAIN CHALLENGE FOR TODAY IS WITH TIMING OF REDEVELOPMENT. UPPER
WAVE ACROSS THE CENTRAL PLAINS EXPECTED TO TRACK INTO WESTERN
MISSOURI LATER TODAY...WITH THE NAM AND HRRR BOTH DEVELOPING
CONVECTION BY MID AFTERNOON. HOWEVER...THE HRRR ALSO LIFTS
CONVECTION CURRENTLY IN SOUTHERN MISSOURI/NORTHERN ARKANSAS
NORTHWARD AND BRINGS IT NEAR A JACKSONVILLE TO EFFINGHAM LINE BY
MID AFTERNOON. THE PREVIOUS AFTERNOON POP GRIDS HAD THAT
PARTICULAR SCENARIO ALREADY IN PLACE...AND RECENT UPDATES
CONTINUED THAT GENERAL TREND EXCEPT TO INCREASE THE POP`S A BIT
MID/LATE AFTERNOON.
&&
.SHORT TERM...(TODAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
07Z/2AM SURFACE ANALYSIS SHOWS A 1012MB LOW OVER WESTERN
WISCONSIN...WITH A WARM FRONT ARCING SOUTHEASTWARD INTO NORTH-
CENTRAL ILLINOIS. SURFACE WINDS AT ALL KILX OB SITES HAVE VEERED TO
THE S/SW...SO THINK FRONT IS NOW JUST NORTH OF THE AREA ALONG A
MOLINE TO KANKAKEE LINE. WIDELY SCATTERED SHOWERS CONTINUE SOUTH OF
THE FRONT...ALTHOUGH RADAR IS SHOWING A DISTINCT DIMINISHING TREND.
WITH WARM FRONT LIFTING FURTHER NORTHWARD THIS MORNING...FORCING FOR
ADDITIONAL CONVECTION WILL BE WEAK. AS A RESULT...THINK ONLY
ISOLATED SHOWERS/THUNDER WILL BE PRESENT ACROSS THE AREA THROUGH
MIDDAY. AS THE DAY PROGRESSES...A WEAK SHORT-WAVE TROUGH NOTED ON
LATEST WATER VAPOR IMAGERY OVER TEXAS WILL APPROACH FROM THE
SOUTHWEST...PROVIDING ENHANCED LIFT AND GREATER AREAL COVERAGE OF
CONVECTION. 4KM WRF-NMM SHOWS SCATTERED SHOWERS/THUNDER DEVELOPING
IN ADVANCE OF THE WAVE ACROSS MISSOURI BY EARLY AFTERNOON...THEN
SPREADING ACROSS THE SOUTHERN HALF OF THE CWA BY MID TO LATE
AFTERNOON. HAVE FASHIONED THE POPS ACCORDINGLY...FEATURING ONLY
ISOLATED SHOWERS/THUNDER ALONG AND NORTH OF I-74...WITH SCATTERED
WORDING FURTHER SOUTH ACROSS THE REMAINDER OF THE AREA. WILL BE A
WARM AND HUMID DAY...WITH AFTERNOON HIGH TEMPERATURES TOPPING OUT IN
THE UPPER 70S AND LOWER 80S.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 307 AM CDT FRI MAY 15 2015
TEXAS WAVE WILL TRACK THROUGH THE AREA TONIGHT...TRIGGERING WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS. DESPITE MODEST LIFT ASSOCIATED
WITH THIS FEATURE...WILL ONLY CARRY LOW CHANCE POPS AS DAYTIME
INSTABILITY WANES. ANOTHER SHORT-WAVE EMBEDDED WITHIN THE DEEP
SOUTHWESTERLY FLOW PATTERN WILL APPROACH FROM THE SOUTHWEST ON
SATURDAY...WITH MODELS DISAGREEING ON HOW MUCH PRECIP IT WILL
GENERATE. MOST MODELS HAVE BEEN SHOWING THIS FEATURE TRACKING
TOWARD THE OHIO RIVER VALLEY FOR THE PAST FEW RUNS...WHICH WOULD
MEAN THE STRONGEST LIFT AND HIGHEST RAIN CHANCES WOULD BE FOCUSED
ACROSS THE SOUTHEAST CWA. LATEST NAM HAS STRAYED FROM THAT THINKING
AND NOW SPREADS QUITE A BIT OF PRECIP ACROSS THE ENTIRE AREA. HAVE
REJECTED THIS SOLUTION IN FAVOR OF THE CONSENSUS...WHICH STILL KEEPS
THE MAIN INFLUENCE OF THE WAVE FURTHER SOUTHEAST. AS A
RESULT...WILL FOCUS LIKELY POPS ALONG/SOUTH OF I-70 ON SATURDAY WITH
CHANCE POPS FURTHER NORTH AND WEST.
WESTERN CONUS UPPER LOW IS STILL EXPECTED TO TRACK INTO THE NORTHERN
PLAINS BY SUNDAY...WITH TRAILING COLD FRONT TRIGGERING WIDESPREAD
SHOWERS AND THUNDERSTORMS. MOST MODELS INDICATE STRONG/SEVERE
CONVECTION ACROSS NEBRASKA/KANSAS/OKLAHOMA SATURDAY AFTERNOON AND
EVENING...WITH STORMS TRACKING EASTWARD AND WEAKENING AS THEY
APPROACH THE MISSISSIPPI RIVER OVERNIGHT. THINK REMNANT
SHOWERS/THUNDERSTORMS WILL SPILL INTO WEST-CENTRAL ILLINOIS SUNDAY
MORNING BEFORE DISSIPATING TOWARD MIDDAY. ADDITIONAL DEVELOPMENT
WILL BE LIKELY LATER IN THE DAY...HOWEVER DEGREE OF
DESTABILIZATION IS IN QUESTION DUE TO CLOUD DEBRIS FROM THE
MORNING PRECIP. WITH SURFACE DEWPOINTS WELL INTO THE 60S...ANY
AMOUNT OF HEATING WILL EASILY CREATE SBCAPES OF 1500 TO 2500J/KG.
IN ADDITION...0-6KM BULK SHEAR WILL INCREASE TO OVER 40KT AS THE
WESTERN TROUGH APPROACHES. STILL DIFFICULT TO PIN DOWN EXACT
SEVERE WEATHER THREAT...HOWEVER THINK THUNDERSTORMS WILL BE LIKELY
WITH A FEW POSSIBLY BECOMING SEVERE DURING THE AFTERNOON AND
EVENING. MAIN THREATS WOULD BE DAMAGING WIND GUSTS AND LARGE
HAIL.
WHILE ACTUAL COLD FRONT REMAINS WELL TO THE WEST...MOST
MODELS SUGGEST THE MAIN BAND OF ACTIVE CONVECTION WILL SHIFT E/SE
INTO THE OHIO RIVER VALLEY SUNDAY NIGHT. WILL THEREFORE CONFINE
CHANCE POPS TO AREAS EAST OF THE I-55 CORRIDOR. FRONT WILL PUSH
THROUGH THE AREA ON MONDAY...WITH POTENTIAL RE-DEVELOPMENT OF
STORMS ALONG THE BOUNDARY LATER IN THE DAY. WILL HANG ON TO LOW
CHANCE POPS ACROSS THE FAR E/SE ACCORDINGLY...HOWEVER IT APPEARS
GREATEST CHANCE FOR ADDITIONAL THUNDER WILL BE FURTHER EAST INTO
INDIANA AND KENTUCKY.
ONCE THE FRONT PASSES...UNSEASONABLY STRONG CANADIAN HIGH PRESSURE
WILL SETTLE INTO THE REGION NEXT WEEK. WITH 850MB TEMPS PROGGED TO
DROP INTO THE SINGLE DIGITS...CORRESPONDING HIGHS WILL FALL BACK
INTO THE 60S AND LOWS WILL DIP INTO THE 40S TUESDAY THROUGH
THURSDAY. A WEAK UPPER-LEVEL WAVE WILL TRY TO APPROACH FROM THE
WEST BY MID-WEEK...BUT THINK IT WILL HAVE LITTLE IMPACT ON THE
WEATHER DUE TO THE COOL/DRY AIRMASS ACROSS THE REGION. GFS IS
AGGRESSIVELY PUSHING SHOWERS INTO THE AREA WEDNESDAY/WEDNESDAY
NIGHT...BUT AM GOING WITH A DRY FORECAST AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 648 AM CDT FRI MAY 15 2015
PREDOMINANTLY QUIET/VFR AVIATION WEATHER FORECAST EXPECTED ACROSS
THE CENTRAL ILLINOIS TERMINALS THROUGH THE 12Z TAF VALID TIME. A
WARM FRONT HAS LIFTED NORTH OF THE REGION OVERNIGHT, WITH SOUTH
TO SOUTHWEST WINDS ANTICIPATED THROUGH THE PERIOD. A WEAK UPPER
LEVEL DISTURBANCE WILL LIFT ACROSS THE AREA LATE THIS EVENING INTO
TONIGHT, POSSIBLY ACCOMPANIED BY A FEW SHOWERS/STORMS.
PRECIPITATION COVERAGE SHOULD BE LOW, AND CONFIDENCE IN THE
EXPLICIT TIMING IS NOT HIGH. SO, HAVE ONLY GONE WITH A VCSH
MENTION DURING THE NIGHTTIME HOURS. IF A HEAVIER SHOWER/STORM
IMPACTS A TERMINAL, MVFR CONDITIONS ARE POSSIBLE TONIGHT, BUT
OTHERWISE VFR CONDITIONS ARE EXPECTED TO PREVAIL.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
255 AM CDT FRI MAY 15 2015
.UPDATE...
941 PM CDT
LIGHTNING STRIKES HAVE BEEN LIMITED SOUTH OF THE AREA THIS
EVENING. WHILE THE FIRST MAIN WAVE OF RAIN IS THROUGH...ADDITIONAL
SHOWERS WILL CONTINUE THIS EVENING AREA WIDE...WITH THE FOCUS
SHIFTING FARTHER SOUTH THROUGH THE NIGHT. WHILE THE THUNDER WAS
REMOVED FOR THE EVENING PERIOD...WILL HOLD ONTO THE ISOLATED
THUNDER MENTION OVERNIGHT AS BETTER LAPSE RATES ALOFT ADVECT
NORTHWARD AND RAP HANGS ONTO SOME WEAK MOST UNSTABLE CAPE. ONE
LONE CLOUD TO GROUND STRIKE OCCURRED IN CHAMPAIGN COUNTY NOT TOO
LONG AGO. AREAS SOUTH OF I-80 HOLD THE BEST CHANCE FOR AN ISOLATED
STRIKE OR TWO.
KMD
&&
.SHORT TERM...
253 PM CDT
THROUGH FRIDAY...
AN ELONGATED NEGATIVELY-TILTED UPPER TROUGH...EXTENDING FROM THE RED
RIVER VALLEY OF THE NORTH TO SOUTHERN ILLINOIS THIS AFTERNOON...WILL
CONTINUE ITS ADVANCE NORTHEAST TONIGHT. WHILE THERE ARE MULTIPLE
EMBEDDED SHORT WAVE IMPULSES WITHIN THIS...THE MOST PRONOUNCED FOR
OUR AREA IS A CIRCULATION CENTER NEAR THE IA/MO/IL BORDER. FOCUSED
ASCENT JUST AHEAD OF THIS IS IN TANDEM WITH A 40 KT LOW-LEVEL JET
PER ILX AND LSX VWP DATA...AND REGIONAL RADAR MOSAIC INDICATES
SHOWERS INCREASING IN COVERAGE AND INTENSITY ACROSS WESTERN ILLINOIS
AND EASTERN MISSOURI AS OF 230 PM.
THIS FAVORED AREA OF FORCING AND SHOWERS WILL EXPAND INTO THE
ILLINOIS FORECAST AREA BY EARLY EVENING. HAVE GONE AS DETERMINISTIC
AS COULD WITH HOURLY POPS...LEVERAGING SOME ON CONVECTIVE ALLOWING
MODELS/ENSEMBLES AND MORE SO OBSERVATIONAL TRENDS. DEEPER PWATS
AROUND 1.4 INCHES AND SLIGHTLY BETTER LAPSE RATES ALOFT IMMEDIATELY
AHEAD OF THE CIRCULATION SUPPORT CHANCES FOR ISOLATED EMBEDDED
THUNDER THIS EVENING. TOO LITTLE OF RECOVERY TIME FOR LAPSE RATES
SHOULD STUNT ANY SEVERE WEATHER THREAT.
THE MAIN CHANGE WITH THE FORECAST FOR TONIGHT WAS TO DIMINISH...AND
IN MANY PLACES END... POPS EARLIER OVERNIGHT FROM SOUTHWEST TO
NORTHEAST...BASED HEAVILY ON UPSTREAM OBSERVATIONAL TRENDS WITH HOUR-
TO-HOUR RUNS OF THE RAP/HRRR SEEM TO BE CATCHING UP ON. EXPECT THE
ILLINOIS FORECAST AREA TO HAVE THE LONGEST TIME WITH SHOWERS
/4-6 HOURS/ AND SOME PLACES TO FINISH AROUND ONE HALF INCH...WHILE
TAPERING TO NEAR OR UNDER ONE QUARTER OF AN INCH INTO NORTHWEST
INDIANA.
SIZABLE PRESSURE FALLS AT THE SURFACE WILL KEEP UP SOUTHEAST WINDS
TONIGHT AND TEMPERATURES REALLY SHOULD ONLY DROP BY WET BULB
COOLING. THE WINDS SHOULD ALSO PREVENT FOG FROM BEING MUCH OF A
PROBLEM ONCE THE RAIN ENDS...AT LEAST OVER LAND. LOWS ARE EXPECTED
IN THE MID-UPPER 50S AREAWIDE.
DURING THE DAY FRIDAY FORCING IS FAIRLY MINIMAL FOR RAIN...SO
CONTINUE POPS LOW OR NON-MENTIONABLE. A SYNOPTIC BOUNDARY STARTS TO
TAKE SHAPE FROM EAST-TO-WEST ACROSS CENTRAL ILLINOIS AND
CONVERGENCE/MOISTURE TRANSPORT INTO AND ALONG THIS WILL START TO
GRADUALLY STRENGTHEN DURING THE AFTERNOON. THIS IS WHERE HAVE KEPT
THE POPS. CONFIDENCE IS SOMEWHAT SHAKE ON HOW QUICKLY CLOUDS
SCATTER...BUT HAVE HIGHS RECOVERING FROM MID 70S TO LOWER 80S FROM
NORTH-TO-SOUTH.
MTF
&&
.LONG TERM...
253 PM CDT
FRIDAY NIGHT THROUGH THURSDAY...
UPPER LEVEL RIDGING WILL TRANSLATE ACROSS NORTHERN ILLINOIS FRIDAY
NIGHT INTO EARLY SATURDAY HOWEVER BOTH THE NAM AND GFS ADVERTISE
A SUBTLE SHORTWAVE EMBEDDED WITHIN THE UPPER RIDGE LIFTING ACROSS
THE AREA FRIDAY NIGHT. SOUNDINGS SHOW MODEST INSTABILITY WILL BE
IN PLACE OVERNIGHT AND ANY LIFT ASSOCIATED WITH THE SHORTWAVE MAY
BE ABLE TO TRIGGER A FEW THUNDERSTORMS. FORCING IS OTHERWISE
FAIRLY WEAK SO THINK COVERAGE SHOULD BE FAIRLY SCATTERED.
MEANWHILE...JET STREAM ROUNDING THE BASE OF THE LONGWAVE TROUGH
CENTERED OVER THE INTERMOUNTAIN WEST WILL LIFT INTO THE CENTRAL
PLAINS SATURDAY WITH SURFACE LOW DEVELOPING OVER WESTERN KS/NE
SATURDAY AFTERNOON. THE MIDWEST WILL ALREADY BE UNDER A MOIST
AIRMASS WITH WIDE OPEN GULF...BUT THIS NEXT WAVE WILL FURTHER
INCREASE MOISTURE WITH PWATS PUSHING 1.5-1.6 INCHES BY LATER IN THE
DAY SATURDAY. HIGHS IN THE LOW TO MID 80S AND SURFACE DEW POINTS IN
THE MID 60S WILL RESULT IN MODERATE INSTABILITY ACROSS THE
AREA...WEAKLY CAPPED OR UNCAPPED PER FORECAST SOUNDINGS. MOST
MODELS INDICATE WIDESPREAD CONVECTIVE ACTIVITY IN THE WARM
SECTOR ACROSS THE MIDWEST AND MISSISSIPPI RIVER VALLEY WHILE THE
MOST FOCUSED FORCING REMAINS WEST OF THE MISSISSIPPI RIVER. GIVEN
THE INSTABILITY AND WEAK FORCING...WILL BE HARD TO PIN DOWN MOST
FAVORED AREAS FOR THUNDERSTORM ACTIVITY BUT GENERALLY EXPECT
SCATTERED UNORGANIZED ACTIVITY WHICH MAY END UP BEING DIURNALLY
FAVORED.
A LOW LEVEL JET FORMS SATURDAY NIGHT FOCUSED ACROSS THE MID-
MISSOURI VALLEY AND SHIFTING EAST ACROSS IOWA DURING THE
OVERNIGHT HOURS. BEST PRECIP CHANCES WILL BE ACROSS THESE AREAS
SATURDAY NIGHT WHILE MODELS CONTINUE TO PRODUCE WIDELY SCATTERED
UNORGANIZED ACTIVITY ACROSS THE LOCAL FORECAST AREA GIVEN THE
CONTINUED INSTABILITY.
SUNDAY CONTINUES TO APPEAR AT LEAST FAVORABLE FOR SEVERE WEATHER
IN THE AREA. EARLY DAY SOUNDINGS SHOW A CAP IN PLACE WHICH
SHOULD HELP ANY FESTERING NOCTURNAL CONVECTION MOVING IN FROM OUR
WEST DISSIPATE...AND FOR INSTABILITY TO BUILD THROUGH THE MORNING
AND EARLY AFTERNOON. MID/HIGH LEVEL CLOUD COVER MAY IMPEDE
INSOLATION SOME...HOWEVER GUIDANCE CONTINUES TO ADVERTISE A
CORRIDOR OF 1000+ J/KG MLCAPE AHEAD OF THE COLD FRONT MOVING
ACROSS NORTHERN ILLINOIS LATE AFTERNOON INTO THE EVENING. IN
ADDITION...NEGATIVELY TILTED TROUGH IS PROGGED TO LIFT INTO THE
UPPER MIDWEST SUNDAY WHICH SHOULD HELP ERODE THE CAP...AND THE JET
STREAM ADVECTS OVERHEAD RESULTING IN INCREASING DEEP LAYER SHEAR.
LATEST GFS ADVERTISES 35-45 KT OF FAIRLY UNIDIRECTIONAL 0-6KM
SHEAR MOVING OVER THE AREA WHICH WILL BE SUFFICIENT TO SUPPORT AN
ORGANIZED SEVERE WEATHER THREAT SHOULD THE INSTABILITY AND FORCING
MATERIALIZE AS EXPECTED.
THE COLD FRONT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWEST
INDIANA EARLY ON MONDAY WITH INITIALLY BREEZY NORTHWEST/NORTH WIND
BEHIND THE FRONT AS STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. COLD ADVECTION AND WINDS TURNING OFF OF LAKE MICHIGAN
WILL RESULT IN TEMPERATURES RETURNING TO COLDER THAN NORMAL
LEVELS...ESPECIALLY TUESDAY WHERE HIGHS MAY ONLY TOP OUT IN THE
50S...THEN GRADUALLY MODERATING AS WE HEAD THROUGH MIDWEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* INTERMITTENT SHRA CONTINUES THROUGH THE EARLY OVERNIGHT HOURS.
* CIGS LOWER TO IFR LATE TONIGHT THEN SLOWLY IMPROVE FROM MID
MORNING THROUGH EARLY AFTERNOON.
* SOUTH-SOUTHEAST WINDS TURN SOUTHWEST BY MID MORNING WITH SPEEDS
INCREASING TO 10-15 KT WITH SOME GUSTS INTO THE UPPER TEENS
POSSIBLE.
* ADDITIONAL SCATTERED SHRA/TSRA ACTIVITY POSSIBLE THIS EVENING.
MDB
//DISCUSSION...UPDATED 06Z...
AN UPPER LEVEL DISTURBANCE PASSING OVERHEAD AND A SURFACE LOW TO
THE NORTHWEST CONTINUE TO INFLUENCE OUR WEATHER EARLY TONIGHT.
WAVES OF SHRA CONTINUE WITH THE BULK OF THE ACTIVITY HAVING
CLEARED TO THE EAST OF THE TERMINALS...BUT ADDITIONAL SCATTERED
SHOWERS ARE APPROACHING FROM THE WEST. THESE WILL CROSS THE AREA
OVER THE NEXT SEVERAL HOURS WITH DRY CONDITIONS BUILDING IN
BEHIND. LOWERING CIGS ARE A CONCERN WITH A LARGE AREA OF IFR TO
THE WEST. HAVE SLOWED THE ARRIVAL OF IFR AT THE TERMINALS BUT THIS
MAY NOT BE SLOW ENOUGH...THOUGH DO EXPECT IFR TO BE IN PLACE FOR
THE MORNING RUSH. CIGS WILL GRADUALLY LIFT THROUGH THE LATE
MORNING THEN LIKELY BECOME VFR EARLY/MID AFTERNOON. CIGS MAY
SCATTER SO MAY ALSO NEED TO INCLUDE LOWER CLOUD COVERAGE BY MID
AFTERNOON.
SOUTHEASTERLY WINDS ARE TRENDING SOUTHERLY AND WILL SHIFT TO THE
SOUTHWEST AFTER DAYBREAK WITH SPEEDS INCREASING SOMEWHAT BY MID
MORNING. WILL CONTINUE WITH CURRENT MENTION OF LLWS GIVEN WIND
SPEEDS AROUND 40 KT TOWARD 2000 FT WITH LIGHTER WINDS AT THE
SURFACE. WINDS OFF THE DECK WILL DECREASE OVER THE NEXT FEW HOURS.
SPEEDS WILL THEN EASE THIS AFTERNOON WITH A TENDENCY FOR A MORE
WEST-SOUTHWEST DIRECTION. SPEEDS LOOK STRONG ENOUGH TO KEEP A
LAKE BREEZE CONFINED TO THE SHORELINE. WINDS WILL FURTHER EASE
THIS EVENING AND TURN TO THE SOUTH AS A WARM FRONTAL BOUNDARY
MOVES NORTH ACROSS THE TERMINALS. THIS MAY ALSO TRIGGER SOME
SCATTERED SHRA/TSRA THIS EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN INTERMITTENT SHRA CONTINUING FOR SEVERAL MORE
HOURS.
* MEDIUM-HIGH CONFIDENCE IN CIGS LOWERING TO IFR. MEDIUM
CONFIDENCE IN TIMING...MAY NEED TO SLOW ARRIVAL DOWN. HIGH
CONFIDENCE IN CIGS IMPROVING TO VFR BUT MEDIUM CONFIDENCE IN
TIMING.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN GUST SPEEDS
MID/LATE MORNING. MAY NEED TO NUDGE THEM UP SLIGHTLY.
* MEDIUM CONFIDENCE IN SCATTERED SHRA/TSRA THIS EVENING.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE. MODERATE SOUTH WINDS.
SUNDAY...SHRA/TSRA LIKELY. MVFR POSSIBLE. STRONG/GUSTY SOUTH
WINDS.
MONDAY...SLIGHT CHANCE LINGERING SHRA EARLY. WINDS TURNING
NWLY...THEN NLY OVERNIGHT.
TUESDAY AND WEDNESDAY...VFR/WX NIL. MODERATE NELY TO ELY WINDS.
KREIN
&&
.MARINE...
253 AM CDT
WEAK LOW PRESSURE OVER WESTERN WISCONSIN EARLY THIS
MORNING WILL MOVE EAST ACROSS UPPER MICHIGAN AND WEAKEN TODAY.
FAIRLY STEADY SOUTH TO SOUTHEAST WINDS WILL DIMINISH THIS AFTERNOON
AS THE PRESSURE GRADIENT WEAKENS BEHIND THE LOW AS A WEAK HIGH MOVES
ACROSS THIS SAME AREA TONIGHT. THIS WILL LIKELY LEAD TO LIGHT
ONSHORE FLOW DEVELOPING LATER THIS AFTERNOON. A WARM FRONTAL
BOUNDARY DEVELOPS AND MOVES NORTH ACROSS THE LAKE TONIGHT ALLOWING
THE WINDS TO TREND SOUTHERLY BUT THE PRESSURE GRADIENT WILL BE WEAK
THROUGH MUCH OF SATURDAY WHICH WILL ALLOW ANOTHER LAKE
BREEZE/ONSHORE FLOW TO DEVELOP. STRONG LOW PRESSURE WILL BE
DEVELOPING ACROSS THE NORTHERN PLAINS SATURDAY AND SATURDAY NIGHT
ALLOWING THE GRADIENT TO STEADILY TIGHTEN LEADING TO A STEADIER
SOUTH TO SOUTH-SOUTHEAST WIND FOR SUNDAY. WITH MUCH WARMER AIR
SPREADING ACROSS THE LAKE GUSTS WILL BE MUTED BUT NEARSHORE AREAS
WILL SEE MIXING SPREAD OFFSHORE AND LIKELY SEE THE STRONGEST WINDS
BEFORE THE STABLE LAYER TAKES OVER FURTHER OFFSHORE. FOG WILL LIKELY
DEVELOP TONIGHT AND PERSIST ACROSS MUCH OF THE LAKE THROUGH SUNDAY
NIGHT. FOG MAY BECOME DENSE WITH MINIMAL VISIBILITY ACROSS THE OPEN
WATERS...WHILE FAR SOUTHERN AREAS WILL PROBABLY SEE BETTER
VISIBILITY AS SOUTH WINDS INCREASE LATER SATURDAY.
THE LOW PEAKS IN INTENSITY LATER SUNDAY ACROSS CENTRAL MINNESOTA
THEN WEAKENS AS IT MOVES ACROSS LAKE SUPERIOR MONDAY. A COLD FRONT
WILL EXTEND FROM THE LOW AND MOVE ACROSS THE LAKE SUNDAY NIGHT OR
MONDAY MORNING BRINGING A SHIFT TO SOUTHWEST THEN WEST WINDS INTO
MONDAY EVENING. SPEEDS WILL PICK UP AND MIXING WILL BEGIN TO DEVELOP
AS COLDER AIR SPREADS INTO THE REGION. STRONG LOW PRESSURE WILL BE
SETTLING SOUTHWARD INTO THE PLAINS KEEPING THE PRESSURE GRADIENT
TIGHT AND COMBINE WITH THE COLD ADVECTION TO BRING A PERIOD OF
FAIRLY GUSTY WEST TO NORTHWEST WINDS MONDAY NIGHT/TUESDAY. ITS STILL
A WAYS OUT FOR DETAILS BUT SPEEDS MAY PUSH 30 KT LATER MONDAY/MONDAY
NIGHT...ESPECIALLY NORTH WHERE THE BEST MIXING IS EXPECTED.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1241 AM CDT FRI MAY 15 2015
.UPDATE...
941 PM CDT
LIGHTNING STRIKES HAVE BEEN LIMITED SOUTH OF THE AREA THIS
EVENING. WHILE THE FIRST MAIN WAVE OF RAIN IS THROUGH...ADDITIONAL
SHOWERS WILL CONTINUE THIS EVENING AREA WIDE...WITH THE FOCUS
SHIFTING FARTHER SOUTH THROUGH THE NIGHT. WHILE THE THUNDER WAS
REMOVED FOR THE EVENING PERIOD...WILL HOLD ONTO THE ISOLATED
THUNDER MENTION OVERNIGHT AS BETTER LAPSE RATES ALOFT ADVECT
NORTHWARD AND RAP HANGS ONTO SOME WEAK MOST UNSTABLE CAPE. ONE
LONE CLOUD TO GROUND STRIKE OCCURRED IN CHAMPAIGN COUNTY NOT TOO
LONG AGO. AREAS SOUTH OF I-80 HOLD THE BEST CHANCE FOR AN ISOLATED
STRIKE OR TWO.
KMD
&&
.SHORT TERM...
253 PM CDT
THROUGH FRIDAY...
AN ELONGATED NEGATIVELY-TILTED UPPER TROUGH...EXTENDING FROM THE RED
RIVER VALLEY OF THE NORTH TO SOUTHERN ILLINOIS THIS AFTERNOON...WILL
CONTINUE ITS ADVANCE NORTHEAST TONIGHT. WHILE THERE ARE MULTIPLE
EMBEDDED SHORT WAVE IMPULSES WITHIN THIS...THE MOST PRONOUNCED FOR
OUR AREA IS A CIRCULATION CENTER NEAR THE IA/MO/IL BORDER. FOCUSED
ASCENT JUST AHEAD OF THIS IS IN TANDEM WITH A 40 KT LOW-LEVEL JET
PER ILX AND LSX VWP DATA...AND REGIONAL RADAR MOSAIC INDICATES
SHOWERS INCREASING IN COVERAGE AND INTENSITY ACROSS WESTERN ILLINOIS
AND EASTERN MISSOURI AS OF 230 PM.
THIS FAVORED AREA OF FORCING AND SHOWERS WILL EXPAND INTO THE
ILLINOIS FORECAST AREA BY EARLY EVENING. HAVE GONE AS DETERMINISTIC
AS COULD WITH HOURLY POPS...LEVERAGING SOME ON CONVECTIVE ALLOWING
MODELS/ENSEMBLES AND MORE SO OBSERVATIONAL TRENDS. DEEPER PWATS
AROUND 1.4 INCHES AND SLIGHTLY BETTER LAPSE RATES ALOFT IMMEDIATELY
AHEAD OF THE CIRCULATION SUPPORT CHANCES FOR ISOLATED EMBEDDED
THUNDER THIS EVENING. TOO LITTLE OF RECOVERY TIME FOR LAPSE RATES
SHOULD STUNT ANY SEVERE WEATHER THREAT.
THE MAIN CHANGE WITH THE FORECAST FOR TONIGHT WAS TO DIMINISH...AND
IN MANY PLACES END... POPS EARLIER OVERNIGHT FROM SOUTHWEST TO
NORTHEAST...BASED HEAVILY ON UPSTREAM OBSERVATIONAL TRENDS WITH HOUR-
TO-HOUR RUNS OF THE RAP/HRRR SEEM TO BE CATCHING UP ON. EXPECT THE
ILLINOIS FORECAST AREA TO HAVE THE LONGEST TIME WITH SHOWERS
/4-6 HOURS/ AND SOME PLACES TO FINISH AROUND ONE HALF INCH...WHILE
TAPERING TO NEAR OR UNDER ONE QUARTER OF AN INCH INTO NORTHWEST
INDIANA.
SIZABLE PRESSURE FALLS AT THE SURFACE WILL KEEP UP SOUTHEAST WINDS
TONIGHT AND TEMPERATURES REALLY SHOULD ONLY DROP BY WET BULB
COOLING. THE WINDS SHOULD ALSO PREVENT FOG FROM BEING MUCH OF A
PROBLEM ONCE THE RAIN ENDS...AT LEAST OVER LAND. LOWS ARE EXPECTED
IN THE MID-UPPER 50S AREAWIDE.
DURING THE DAY FRIDAY FORCING IS FAIRLY MINIMAL FOR RAIN...SO
CONTINUE POPS LOW OR NON-MENTIONABLE. A SYNOPTIC BOUNDARY STARTS TO
TAKE SHAPE FROM EAST-TO-WEST ACROSS CENTRAL ILLINOIS AND
CONVERGENCE/MOISTURE TRANSPORT INTO AND ALONG THIS WILL START TO
GRADUALLY STRENGTHEN DURING THE AFTERNOON. THIS IS WHERE HAVE KEPT
THE POPS. CONFIDENCE IS SOMEWHAT SHAKE ON HOW QUICKLY CLOUDS
SCATTER...BUT HAVE HIGHS RECOVERING FROM MID 70S TO LOWER 80S FROM
NORTH-TO-SOUTH.
MTF
&&
.LONG TERM...
253 PM CDT
FRIDAY NIGHT THROUGH THURSDAY...
UPPER LEVEL RIDGING WILL TRANSLATE ACROSS NORTHERN ILLINOIS FRIDAY
NIGHT INTO EARLY SATURDAY HOWEVER BOTH THE NAM AND GFS ADVERTISE
A SUBTLE SHORTWAVE EMBEDDED WITHIN THE UPPER RIDGE LIFTING ACROSS
THE AREA FRIDAY NIGHT. SOUNDINGS SHOW MODEST INSTABILITY WILL BE
IN PLACE OVERNIGHT AND ANY LIFT ASSOCIATED WITH THE SHORTWAVE MAY
BE ABLE TO TRIGGER A FEW THUNDERSTORMS. FORCING IS OTHERWISE
FAIRLY WEAK SO THINK COVERAGE SHOULD BE FAIRLY SCATTERED.
MEANWHILE...JET STREAM ROUNDING THE BASE OF THE LONGWAVE TROUGH
CENTERED OVER THE INTERMOUNTAIN WEST WILL LIFT INTO THE CENTRAL
PLAINS SATURDAY WITH SURFACE LOW DEVELOPING OVER WESTERN KS/NE
SATURDAY AFTERNOON. THE MIDWEST WILL ALREADY BE UNDER A MOIST
AIRMASS WITH WIDE OPEN GULF...BUT THIS NEXT WAVE WILL FURTHER
INCREASE MOISTURE WITH PWATS PUSHING 1.5-1.6 INCHES BY LATER IN THE
DAY SATURDAY. HIGHS IN THE LOW TO MID 80S AND SURFACE DEW POINTS IN
THE MID 60S WILL RESULT IN MODERATE INSTABILITY ACROSS THE
AREA...WEAKLY CAPPED OR UNCAPPED PER FORECAST SOUNDINGS. MOST
MODELS INDICATE WIDESPREAD CONVECTIVE ACTIVITY IN THE WARM
SECTOR ACROSS THE MIDWEST AND MISSISSIPPI RIVER VALLEY WHILE THE
MOST FOCUSED FORCING REMAINS WEST OF THE MISSISSIPPI RIVER. GIVEN
THE INSTABILITY AND WEAK FORCING...WILL BE HARD TO PIN DOWN MOST
FAVORED AREAS FOR THUNDERSTORM ACTIVITY BUT GENERALLY EXPECT
SCATTERED UNORGANIZED ACTIVITY WHICH MAY END UP BEING DIURNALLY
FAVORED.
A LOW LEVEL JET FORMS SATURDAY NIGHT FOCUSED ACROSS THE MID-
MISSOURI VALLEY AND SHIFTING EAST ACROSS IOWA DURING THE
OVERNIGHT HOURS. BEST PRECIP CHANCES WILL BE ACROSS THESE AREAS
SATURDAY NIGHT WHILE MODELS CONTINUE TO PRODUCE WIDELY SCATTERED
UNORGANIZED ACTIVITY ACROSS THE LOCAL FORECAST AREA GIVEN THE
CONTINUED INSTABILITY.
SUNDAY CONTINUES TO APPEAR AT LEAST FAVORABLE FOR SEVERE WEATHER
IN THE AREA. EARLY DAY SOUNDINGS SHOW A CAP IN PLACE WHICH
SHOULD HELP ANY FESTERING NOCTURNAL CONVECTION MOVING IN FROM OUR
WEST DISSIPATE...AND FOR INSTABILITY TO BUILD THROUGH THE MORNING
AND EARLY AFTERNOON. MID/HIGH LEVEL CLOUD COVER MAY IMPEDE
INSOLATION SOME...HOWEVER GUIDANCE CONTINUES TO ADVERTISE A
CORRIDOR OF 1000+ J/KG MLCAPE AHEAD OF THE COLD FRONT MOVING
ACROSS NORTHERN ILLINOIS LATE AFTERNOON INTO THE EVENING. IN
ADDITION...NEGATIVELY TILTED TROUGH IS PROGGED TO LIFT INTO THE
UPPER MIDWEST SUNDAY WHICH SHOULD HELP ERODE THE CAP...AND THE JET
STREAM ADVECTS OVERHEAD RESULTING IN INCREASING DEEP LAYER SHEAR.
LATEST GFS ADVERTISES 35-45 KT OF FAIRLY UNIDIRECTIONAL 0-6KM
SHEAR MOVING OVER THE AREA WHICH WILL BE SUFFICIENT TO SUPPORT AN
ORGANIZED SEVERE WEATHER THREAT SHOULD THE INSTABILITY AND FORCING
MATERIALIZE AS EXPECTED.
THE COLD FRONT WILL SWEEP ACROSS NORTHERN ILLINOIS AND NORTHWEST
INDIANA EARLY ON MONDAY WITH INITIALLY BREEZY NORTHWEST/NORTH WIND
BEHIND THE FRONT AS STRONG HIGH PRESSURE BUILDS INTO THE NORTHERN
PLAINS. COLD ADVECTION AND WINDS TURNING OFF OF LAKE MICHIGAN
WILL RESULT IN TEMPERATURES RETURNING TO COLDER THAN NORMAL
LEVELS...ESPECIALLY TUESDAY WHERE HIGHS MAY ONLY TOP OUT IN THE
50S...THEN GRADUALLY MODERATING AS WE HEAD THROUGH MIDWEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* INTERMITTENT SHRA CONTINUES THROUGH THE EARLY OVERNIGHT HOURS.
* CIGS LOWER TO IFR LATE TONIGHT THEN SLOWLY IMPROVE FROM MID
MORNING THROUGH EARLY AFTERNOON.
* SOUTH-SOUTHEAST WINDS TURN SOUTHWEST BY MID MORNING WITH SPEEDS
INCREASING TO 10-15 KT WITH SOME GUSTS INTO THE UPPER TEENS
POSSIBLE.
* ADDITIONAL SCATTERED SHRA/TSRA ACTIVITY POSSIBLE THIS EVENING.
MDB
//DISCUSSION...UPDATED 06Z...
AN UPPER LEVEL DISTURBANCE PASSING OVERHEAD AND A SURFACE LOW TO
THE NORTHWEST CONTINUE TO INFLUENCE OUR WEATHER EARLY TONIGHT.
WAVES OF SHRA CONTINUE WITH THE BULK OF THE ACTIVITY HAVING
CLEARED TO THE EAST OF THE TERMINALS...BUT ADDITIONAL SCATTERED
SHOWERS ARE APPROACHING FROM THE WEST. THESE WILL CROSS THE AREA
OVER THE NEXT SEVERAL HOURS WITH DRY CONDITIONS BUILDING IN
BEHIND. LOWERING CIGS ARE A CONCERN WITH A LARGE AREA OF IFR TO
THE WEST. HAVE SLOWED THE ARRIVAL OF IFR AT THE TERMINALS BUT THIS
MAY NOT BE SLOW ENOUGH...THOUGH DO EXPECT IFR TO BE IN PLACE FOR
THE MORNING RUSH. CIGS WILL GRADUALLY LIFT THROUGH THE LATE
MORNING THEN LIKELY BECOME VFR EARLY/MID AFTERNOON. CIGS MAY
SCATTER SO MAY ALSO NEED TO INCLUDE LOWER CLOUD COVERAGE BY MID
AFTERNOON.
SOUTHEASTERLY WINDS ARE TRENDING SOUTHERLY AND WILL SHIFT TO THE
SOUTHWEST AFTER DAYBREAK WITH SPEEDS INCREASING SOMEWHAT BY MID
MORNING. WILL CONTINUE WITH CURRENT MENTION OF LLWS GIVEN WIND
SPEEDS AROUND 40 KT TOWARD 2000 FT WITH LIGHTER WINDS AT THE
SURFACE. WINDS OFF THE DECK WILL DECREASE OVER THE NEXT FEW HOURS.
SPEEDS WILL THEN EASE THIS AFTERNOON WITH A TENDENCY FOR A MORE
WEST-SOUTHWEST DIRECTION. SPEEDS LOOK STRONG ENOUGH TO KEEP A
LAKE BREEZE CONFINED TO THE SHORELINE. WINDS WILL FURTHER EASE
THIS EVENING AND TURN TO THE SOUTH AS A WARM FRONTAL BOUNDARY
MOVES NORTH ACROSS THE TERMINALS. THIS MAY ALSO TRIGGER SOME
SCATTERED SHRA/TSRA THIS EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN INTERMITTENT SHRA CONTINUING FOR SEVERAL MORE
HOURS.
* MEDIUM-HIGH CONFIDENCE IN CIGS LOWERING TO IFR. MEDIUM
CONFIDENCE IN TIMING...MAY NEED TO SLOW ARRIVAL DOWN. HIGH
CONFIDENCE IN CIGS IMPROVING TO VFR BUT MEDIUM CONFIDENCE IN
TIMING.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN GUST SPEEDS
MID/LATE MORNING. MAY NEED TO NUDGE THEM UP SLIGHTLY.
* MEDIUM CONFIDENCE IN SCATTERED SHRA/TSRA THIS EVENING.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE. MODERATE SOUTH WINDS.
SUNDAY...SHRA/TSRA LIKELY. MVFR POSSIBLE. STRONG/GUSTY SOUTH
WINDS.
MONDAY...SLIGHT CHANCE LINGERING SHRA EARLY. WINDS TURNING
NWLY...THEN NLY OVERNIGHT.
TUESDAY AND WEDNESDAY...VFR/WX NIL. MODERATE NELY TO ELY WINDS.
KREIN
&&
.MARINE...
253 PM CDT
HIGH PRESSURE IS CENTERED EAST OF LAKE MICHIGAN TODAY AND WILL
MOVE TO THE MID ATLANTIC COAST OVERNIGHT. AS THE HIGH DRIFTS
EAST...SOUTHEAST WINDS WILL FRESHEN UP ACROSS LAKE MICHIGAN
TONIGHT. A WEAK LOW WILL TRAVERSE THE REGION FRIDAY LIFTING A WARM
FRONT NORTH ACROSS THE LAKE...THEN A SECOND STRONGER LOW WILL TAKE
SHAPE OVER THE PLAINS FRIDAY AND LIFT INTO THE UPPER MIDWEST BY
SUNDAY BRINGING PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
IN ADDITION...MOISTURE WILL INCREASE ACROSS THE REGION AND STABLE
CONDITIONS OVER THE LAKE WILL BE FAVORABLE FOR FOG TO DEVELOP FOR
MUCH OF THE WEEKEND. A COLD FRONT WILL SWEEP ACROSS LAKE MICHIGAN
EARLY MONDAY AND TURNING WINDS WESTERLY AND SHOULD MARK AND END
FOR PRECIP AND FOG CHANCES.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
1153 PM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 906 PM CDT THU MAY 14 2015
SCATTERED SHOWERS CONTINUE TO MOVE ACROSS THE AREA, MAINLY NORTH
OF I-70. ALREADY MADE ONE ADJUSTMENT TO WX GRIDS TO REMOVE MENTION
OF THUNDER...BUT WILL BE MAKING ANOTHER ADJUSTMENT TO POPS FOR
REMAINDER OF THE NIGHT. HRRR MODEL CONTINUES TO DEVELOP SCATTERED
PCPN JUST TO THE WEST OF THE AREA AND MOVE IT INTO THE CWA.
THEREFORE WILL KEEP SCATTERED SHOWERS MENTIONED IN FORECAST GRIDS.
REMAINDER OF FORECAST LOOK OK BUT WILL SENDING AN UPDATE SHORTLY.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 206 PM CDT THU MAY 14 2015
SHOWERS THUS FAR HAVE CONTINUED TO BATTLE A VERY DRY AIRMASS OVER
CENTRAL ILLINOIS. HOWEVER...A MORE ROBUST AREA OF SHOWERS ASSOCIATED
WITH THE UPPER LOW CURRENTLY TRACKING ACROSS NORTHERN MISSOURI WILL
BE ARRIVING IN THE ILLINOIS RIVER VALLEY BY MID AFTERNOON. THE HRRR
MODEL...WHICH HAS BEEN DOING A DECENT JOB THUS FAR...SHOWS SOME
ADDITIONAL DEVELOPMENT WEST OF I-55 LATE AFTERNOON INTO THE
EVENING... AND HAVE CONCENTRATED THE HIGHER POP`S IN THESE AREAS.
HIGHER-RESOLUTION MODELS SUCH AS THE HRRR AND NMM/ARW AGREE WITH THE
NAM SOLUTION OF THE EVOLUTION OF A MORE EAST-WEST CONFIGURATION OF
SHOWERS ROUGHLY CENTERED ALONG I-72 BY MIDNIGHT. THUNDER UPSTREAM IN
MISSOURI HAS BEEN MINIMAL THUS FAR...AND INSTABILITY PARAMETERS OFF
THE NAM...RAP AND ARW SUGGEST ANY THUNDER IN OUR AREA WOULD BE MOST
LIKELY ALONG AND WEST OF I-55 TONIGHT.
NOT MUCH OF A DROPOFF EXPECTED IN TEMPERATURES TONIGHT...GENERALLY
REMAINING STEADY IN THE LOWER 60S.
.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 206 PM CDT THU MAY 14 2015
IN THE WAKE OF THE WAVE MOVING ACROSS THE MIDWEST TODAY...HEIGHTS
BUILD BRIEFLY AHEAD OF NEXT WEAKER WAVE MOVING NORTHEAST AROUND WEST
COAST CLOSED LOW. HOWEVER, MODELS ARE CONSISTENT IN REDEVELOPING THE
WARM FRONT OVER CENTRAL ILLINOIS FRIDAY AND WITH THE WEAKER WAVE
APPROACHING FRIDAY AFTERNOON, THUNDERSTORMS WILL LIKELY DEVELOP.
WILL NEED TO RETAIN AT LEAST LOW POPS DESPITE THE RIDGING.
INSTABILITY OF 1500-2000 J/KG WILL BE POSSIBLE ALONG AND TO THE
SOUTH OF THE FRONT IN AREAS THAT SEE A LITTLE SUN THOUGH SHEAR WILL
BE QUITE LIMITED.
AS SOUTHERLY FLOW BECOMES ESTABLISHED...DEW POINTS WILL RESPOND BY
CLIMBING INTO THE 60S FOR FRIDAY AFTERNOON AND THE WEEKEND. AS THE
WEST COAST ENERGY BEGINS TO PULL NORTHEAST TOWARD THE GREAT LAKES,
WAVES WILL EJECT FROM THE SYSTEM AND PERIODICALLY CONTRIBUTE TO LIFT
ALONG ANY CONVECTIVELY ENHANCED BOUNDARIES LYING ACROSS THE AREA.
THIS WILL MAKE TIMING OF PRECIPITATION DIFFICULT UNTIL THE MAIN
ENERGY PASSES NORTHWEST OF ILLINOIS ON SUNDAY. WILL HAVE TO
GENERALLY BROADBRUSH GIVEN THE POTENTIAL INSTABILITY (1500-2500
J/KG) IN PLACE. 0-6KM SHEAR IS FORECAST TO REMAIN BELOW 20 KTS
THROUGH SATURDAY EVENING, SO WIDESPREAD SEVERE WEATHER IS NOT
EXPECTED THOUGH GIVEN THE HIGH PRECIPITABLE WATER WOULD NOT BE
SURPRISED TO SEE SOME WET MICROBURST ACTIVITY PRODUCING GUSTY WINDS
AT TIMES SATURDAY.
THE MISSING INGREDIENT (DEEP SHEAR) JOINS THE ENVIRONMENT ON SUNDAY
AS THE MAIN WAVE PASSES NORTHWEST OF ILLINOIS. 0-6KM SHEAR IS
EXPECTED TO SURPASS 40 KTS BY SUNDAY EVENING. THERE DOES SEEM TO
BE POTENTIAL FOR ROTATING UPDRAFTS GIVEN GFS FORECASTED 0-1KM
HELECITY VALUES OF 125-150 M2/S2 AND LCL HEIGHTS BELOW 900 MB.
STORM MOTION ALSO SUGGESTS THAT WINDS MAY BE A THREAT WITH
FORECASTED STORM MOTION AROUND 40 KTS. THREAT WILL LIKELY INCREASE
FROM SOUTHEAST TO NORTHWEST ACROSS FORECAST AREA DUE TO PROXIMITY
OF THE WAVE.
ASSOCIATED COLD FRONT IS EXPECTED TO PUSH THROUGH SUNDAY NIGHT AND
MUCH COOLER TEMPERATURES ARE EXPECTED FOR THE BEGINNING OF THE WORK
WEEK. STILL SOME SPREAD IN LATEST MODELS WITH REGARDS TO HOW MUCH
COLD AIR WILL PENETRATE THE MIDWEST BEHIND FRONT WITH THE ECMWF
COOLER THAN GFS/DGEX. HOWEVER, 12Z GFS IS TRENDING TOWARD THIS
COOLER SOLUTION. WILL COMPROMISE BETWEEN THE TWO SOLUTIONS FOR
NOW AND KEEP AT LEAST SOME LOW POPS IN FOR WED THROUGH THU.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1153 PM CDT THU MAY 14 2015
WIDELY SCATTERED SHOWERS CONTINUE ACROSS THE AREA SO WILL BE
KEEPING VCSH AT ALL TAF SITES THROUGH THE OVERNIGHT HOURS. SHORT
TERM MODELS CONTINUE TO SHOW LOWER/MVFR CIGS ARRIVING DURING THE
MORNING HOURS SO WILL BE KEEPING THOSE LEVEL CIGS IN TAFS DURING
THE MORNING WITH PIA AT 2.5KFT...BMI AT 2KFT AND SPI/DEC/CMI AT
3KFT. THINKING IS THAT DURING THE EARLY AFTERNOON SKIES WILL
BECOME SCATTERED AT ALL SITES. THEN A WEAK BOUNDARY ACROSS THE
MIDDLE OF THE STATE COULD BECOME ACTIVE WITH SCATTERED
THUNDERSTORMS SO WILL HAVE VCTS AT SPI/DEC/CMI. THINK THESE WILL
REMAIN SOUTH OF PIA AND BMI SO WILL JUST HAVE INCREASED VFR CLOUDS
AT 4KFT FOR THE EVENING. WINDS WILL BE SOUTHEAST OVERNIGHT AND
THEN BECOME SOUTHWEST DURING THE MORNING AND THEN SOUTHERLY DURING
THE EVENING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AUTEN
SHORT TERM...GEELHART
LONG TERM...BARKER
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
247 AM EDT FRI MAY 15 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 342 PM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1006 PM EDT THU MAY 14 2015
RADAR LATE THIS EVENING SHOWS A WAVE OF SHOWERS OVER NORTHWEST
CENTRAL INDIANA PUSHING NORTHEAST. MEANWHILE THE REST OF CENTRAL
INDIANA WAS PRECIP FREE...AS WAS THE FLOW UPSTREAM. THUS HAVE
DROPPED POPS OFF FOR THE NEXT FEW HOURS ACROSS MUCH OF THE FORECAST
AREA AS THE WAVE TO THE NORTHWEST BRUSHES BY OUR FORECAST AREA.
HAVE RAMPED POPS BACK UP TO THE LOW CHC CATEGORY AFT 06-07Z..AS
THE HRRR AND GFS SUGGEST SOME SATURATION ACROSS CENTRAL INDIANA IN
ASSOCIATION WITH THE PASSING WAVE. CONFIDENCE IS LOW WIT THIS
FEATURE ANY ANY PRECIP AMOUNT SHOULD BE QUITE LIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 342 PM EDT THU MAY 14 2015
AS PREVIOUSLY MENTIONED IN THE ABOVE NEAR TERM DISCUSSION...THIS
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING. EVENTUALLY
SOME RIDGING ALOFT WILL REESTABLISH ITSELF. THEN THERE IS GOOD
POTENTIAL FOR THE REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY
AFTERNOON WITHIN THIS INCREASINGLY MOIST...WARM...AND UNSTABLE
AIRMASS ACROSS CENTRAL INDIANA. HAVE MAINTAINED SCATTERED POPS FOR
THIS TIME PERIOD AS WELL. SEVERE STORMS ARE NOT ANTICIPATED BUT IF
AND WHEN STRONGER STORMS DEVELOP THEY WILL HAVE THE POTENTIAL TO
PRODUCE HAIL...VERY HEAVY RAINFALL (PER FORECAST PWATS) IN
ADDITION TO STRONG WINDS AND DEADLY CLOUD TO GROUND LIGHTNING.
AS FOR THE REST OF THIS PERIOD CENTRAL INDIANA CAN EXPECT TO SEE
MORE OF THE SAME WITH WARM HUMID CONDITIONS AS GULF MOISTURE
LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT THIS WEEKEND
WILL BE LARGELY DEPENDENT ON AVAILABLE INSTABILITY. CONSIDERING
LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES
NOT WARRANT ANY HIGHER THAN 40 TO 70 POPS AT THIS POINT IN TIME.
ALSO...THIS WEEKEND WILL NOT BE A TOTAL WASHOUT BUT WILL CONTINUE TO
CARRY EITHER SCATTERED OR LIKELY SHOWERS AND THUNDERSTORMS FOR
ON/OFF PERIOD THROUGH THE WEEKEND.
IN TERMS OF TEMPERATURES...GUIDANCE IS IN AGREEMENT SO DID NOT
NEED TO MAKE MANY CHANGES AND GENERALLY USED A BLEND FOR
SUMMERTIME LIKE HIGHS IN THE LOW 80S. LOWS IN THE MID TO UPPER
60S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 247 AM EDT FRI MAY 15 2015
MODELS ARE CLOSE ENOUGH THAT THE SUPERBLEND INITIALIZATION WAS
ACCEPTED FOR MOST ITEMS.
A COLD FRONT WILL BE EXITING THE AREA ON MONDAY SO KEPT SOME LOW
POPS DURING THE DAY. MUCH COLDER AIR WILL THEN BUILD IN FOR THE
REMAINDER OF THE LONG TERM WITH TEMPERATURES REMAINING BELOW AVERAGE
THROUGH THE PERIOD.
UPPER FLOW WILL BECOME MORE ZONAL AND SOME MODELS HINT AT UPPER
WAVES GENERATING LOW CHANCES FOR RAIN MID WEEK. HOWEVER CONFIDENCE
IN TIMING OF THESE WAVES AND IF THEY WILL HAVE ENOUGH MOISTURE FOR
RAIN IS LOW...SO REMOVED ANY POPS AND WENT DRY MON. NIGHT-THURSDAY.
&&
.AVIATION /DISCUSSION FOR THE 15/06Z TAFS/...
ISSUED AT 1245 AM EDT FRI MAY 15 2015
VFR THROUGH MUCH OF THE PERIOD OUTSIDE OF ANY POTENTIAL SPOTTY
SHOWERS OVERNIGHT AND ANY THUNDERSTORMS FRIDAY.
CLOUD COVER GENERALLY AROUND 6-8KFT OVERNIGHT BUT GRADUALLY LOWERING
LATE AND INTO FRIDAY. NO VISIBILITY ISSUES ANTICIPATED OUTSIDE OF
PRECIPITATION.
WINDS WILL BE 10KT OR LESS OUT OF THE SOUTHEAST OVERNIGHT...BECOMING
10 PLUS KNOTS TOMORROW MID MORNING GUSTING AS HIGH AS AROUND
20KT...OUT OF THE SOUTHWEST.
THUNDER CANNOT COMPLETELY BE RULED OUT FRIDAY AFTERNOON...BUT WILL
BE FAR TOO SPOTTY AND UNCERTAIN FOR INCLUSION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...PUMA
SHORT TERM...SMF
LONG TERM...50
AVIATION...NIELD
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1245 AM EDT FRI MAY 15 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 342 PM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1006 PM EDT THU MAY 14 2015
RADAR LATE THIS EVENING SHOWS A WAVE OF SHOWERS OVER NORTHWEST
CENTRAL INDIANA PUSHING NORTHEAST. MEANWHILE THE REST OF CENTRAL
INDIANA WAS PRECIP FREE...AS WAS THE FLOW UPSTREAM. THUS HAVE
DROPPED POPS OFF FOR THE NEXT FEW HOURS ACROSS MUCH OF THE
FORECAST AREA AS THE WAVE TO THE NORTHWEST BRUSHES BY OUR FORECAST AREA.
HAVE RAMPED POPS BACK UP TO THE LOW CHC CATEGORY AFT 06-07Z..AS
THE HRRR AND GFS SUGGEST SOME SATURATION ACROSS CENTRAL INDIANA IN
ASSOCIATION WITH THE PASSING WAVE. CONFIDENCE IS LOW WIT THIS
FEATURE ANY ANY PRECIP AMOUNT SHOULD BE QUITE LIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 342 PM EDT THU MAY 14 2015
AS PREVIOUSLY MENTIONED IN THE ABOVE NEAR TERM DISCUSSION...THIS
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING. EVENTUALLY
SOME RIDGING ALOFT WILL REESTABLISH ITSELF. THEN THERE IS GOOD
POTENTIAL FOR THE REDEVELOPMENT OF SCATTERED CONVECTION ON FRIDAY
AFTERNOON WITHIN THIS INCREASINGLY MOIST...WARM...AND UNSTABLE
AIRMASS ACROSS CENTRAL INDIANA. HAVE MAINTAINED SCATTERED POPS FOR
THIS TIME PERIOD AS WELL. SEVERE STORMS ARE NOT ANTICIPATED BUT IF
AND WHEN STRONGER STORMS DEVELOP THEY WILL HAVE THE POTENTIAL TO
PRODUCE HAIL...VERY HEAVY RAINFALL (PER FORECAST PWATS) IN
ADDITION TO STRONG WINDS AND DEADLY CLOUD TO GROUND LIGHTNING.
AS FOR THE REST OF THIS PERIOD CENTRAL INDIANA CAN EXPECT TO SEE
MORE OF THE SAME WITH WARM HUMID CONDITIONS AS GULF MOISTURE
LIFTS INTO THE OHIO VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. CONVECTIVE DEVELOPMENT THIS WEEKEND
WILL BE LARGELY DEPENDENT ON AVAILABLE INSTABILITY. CONSIDERING
LACK OF EXTENSIVE FORCING ALOFT AND LIMITED BL SHEAR...THIS DOES
NOT WARRANT ANY HIGHER THAN 40 TO 70 POPS AT THIS POINT IN TIME.
ALSO...THIS WEEKEND WILL NOT BE A TOTAL WASHOUT BUT WILL CONTINUE TO
CARRY EITHER SCATTERED OR LIKELY SHOWERS AND THUNDERSTORMS FOR
ON/OFF PERIOD THROUGH THE WEEKEND.
IN TERMS OF TEMPERATURES...GUIDANCE IS IN AGREEMENT SO DID NOT
NEED TO MAKE MANY CHANGES AND GENERALLY USED A BLEND FOR
SUMMERTIME LIKE HIGHS IN THE LOW 80S. LOWS IN THE MID TO UPPER
60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 205 PM EDT THU MAY 14 2015
ENSEMBLES AND DETERMINISTIC MODELS CONTINUE TO SUGGEST A WARM AND
UNSETTLED START TO THE EXTENDED.
THE DETERMINISTIC 12Z GFS AND 00Z ECMWF ALONG WITH THE ENSEMBLE
MEANS ARE IN VERY GOOD AGREEMENT REGARDING THE SYNOPTIC PATTERN FOR
THE EXTENDED. THEY LIFT AN UPPER LOW...CURRENTLY OFF THE CALIFORNIA
COAST...NORTHEAST TO ONTARIO ON MONDAY. THIS WILL ALLOW A FRONTAL
SYSTEM TO SWEEP SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY. THE
FRONT WILL INTERACT WITH WARM...MOIST AND UNSTABLE AIR AND TRIGGER
SCATTERED TO NUMEROUS THUNDERSTORMS SUNDAY NIGHT AND MONDAY...BEFORE
COOLER AND DRY WEATHER RETURN UNDER THE INFLUENCE OF STRONG HIGH
PRESSURE BUILDS IN FROM THE WEST. REGIONAL BLEND POPS HANDLE THIS
WELL WITH GOOD CHANCE POPS SUNDAY NIGHT INTO MONDAY AND DRY BY
MONDAY NIGHT. TO WRAP UP THE EXTENDED...A WEAK SOUTHERN SYSTEM COULD
BRING A FEW SHOWERS OR STORMS TO THE AREA BY NEXT THURSDAY.
TEMPERATURES SHOULD START OFF ABOVE NORMAL AHEAD OF THE COLD FRONT
AND THEN FALL TO BELOW NORMAL BEHIND THE FRONT WITH HIGHS ONLY IN
THE 60S LOOKING GOOD BY TUESDAY PER THE REGIONAL BLEND.
&&
.AVIATION /DISCUSSION FOR THE 15/06Z TAFS/...
ISSUED AT 1245 AM EDT FRI MAY 15 2015
VFR THROUGH MUCH OF THE PERIOD OUTSIDE OF ANY POTENTIAL SPOTTY
SHOWERS OVERNIGHT AND ANY THUNDERSTORMS FRIDAY.
CLOUD COVER GENERALLY AROUND 6-8KFT OVERNIGHT BUT GRADUALLY LOWERING
LATE AND INTO FRIDAY. NO VISIBILITY ISSUES ANTICIPATED OUTSIDE OF
PRECIPITATION.
WINDS WILL BE 10KT OR LESS OUT OF THE SOUTHEAST OVERNIGHT...BECOMING
10 PLUS KNOTS TOMORROW MID MORNING GUSTING AS HIGH AS AROUND
20KT...OUT OF THE SOUTHWEST.
THUNDER CANNOT COMPLETELY BE RULED OUT FRIDAY AFTERNOON...BUT WILL
BE FAR TOO SPOTTY AND UNCERTAIN FOR INCLUSION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...PUMA
SHORT TERM...SMF
LONG TERM...MK
AVIATION...NIELD
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
425 PM CDT FRI MAY 15 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 425 PM CDT FRI MAY 15 2015
LOW PRESSURE CONTINUES TO WORK ITS WAY OFF OF THE ROCKIES AND INTO
NE COLORADO AND SW NEBRASKA THIS AFTERNOON AND WILL BE THE MAIN
DRIVER OF WEATHER OVER THE WEEKEND...BUT NOT IN THIS PERIOD.
INSTEAD...VORTICITY ASSOCIATED WITH A SHORTWAVE MOVING UP THROUGH
THE PLAINS HAS KICKED OFF CONVECTION IN E KANSAS AND W AND C
MISSOURI. THETA-E ADVECTION IS NOT SIGNIFICANT WITH THE CONVECTION
IN KANSAS...BUT IS MORE SO IN MISSOURI AND IS EXPECTED TO INCREASE
LATER THIS AFTERNOON AND EVENING AS THE LOW LEVEL FLOW INCREASES AND
HELPS KEEP SHOWERS AND STORMS GOING AS DAYTIME HEATING AND
INSTABILITY BEGINS TO WANE. A FEW STORMS MAY CONTAIN SEVERE HAIL AND
HIGH WINDS EARLY THIS EVENING WITH CAPE VALUES IN EXCESS OF 1500-
2000 J/KG...WIDESPREAD SEVERE IS NOT EXPECTED THOUGH GIVEN THE LACK
OF SUPPORTIVE SHEAR. SHOWERS AND STORMS ARE ALREADY IN THE SW CWA
AND WILL CONTINUE TO MOVE NORTHEAST...REACHING THE DES MOINES METRO
AROUND 00Z...AND THE WATERLOO AROUND 03Z...WEAKENING AS THE EVENING
GOES ON. THE HIGH-RES MODELS HAVE NOT BEEN IN GREAT AGREEMENT...WITH
THE HRRR OVERLY AGGRESSIVE IN PROGRESSION. THE ARW-EAST HAS THE
BEST HANDLE ON CONVECTION CURRENTLY...AND HAVE LEANED THAT WAY FOR
POPS THIS EVENING. AM EXPECTING LOCALLY DENSE FOG OVERNIGHT...AS
WELL...WITH HIGH DEW PTS FROM INCOMING PRECIP AND SOLID MOISTURE
TRANSPORT THROUGH THE EVENING AND OVERNIGHT...BUT WILL REFRAIN
FROM WIDESPREAD FOR NOT AND DENOTE PATCHY FOG.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 425 PM CDT FRI MAY 15 2015
DYNAMIC UPPER LEVEL SYSTEM EXTENDING FROM SOUTHERN CALIFORNIA
THROUGH IDAHO WILL SEGMENT INTO TWO SECTIONS WITH ONE SEGMENT
LIFTING INTO WYOMING AND MONTANA AND LINGERING THERE THROUGH
SUNDAY. THE STRONGER SEGMENT WILL MOVE EAST THROUGH THE DESERT
SOUTHWEST ON SUNDAY THEN LIFT NORTHEAST THROUGH THE TEXAS
PANHANDLE LATE SATURDAY THEN OVER EASTERN NEBRASKA BY EARLY
SUNDAY. THE INITIAL SHORTWAVE THAT WILL MOVE ACROSS IOWA OVERNIGHT
WILL LEAVE SOME STABILITY THROUGH THE MORNING WITH THE PASSAGE OF
MID LEVEL DRY AIR. INSTABILITY WILL DEVELOP BY THE AFTERNOON
THROUGH SFC HEATING HOWEVER NO GOOD FORCING MECHANISM WILL BE
AVAILABLE AND THIS SHOULD LIMIT THE AREAL COVERAGE OF THUNDERSTORM
DEVELOPMENT. THE STRONGER THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING WILL INITIALIZE ACROSS NEBRASKA AND KANSAS. THESE STORMS
SHOULD MOVE INTO WESTERN IOWA SATURDAY NIGHT AS THE UPPER LEVEL
SYSTEM ADVANCES NORTHEAST. A FEW SEVERE STORMS ARE POSSIBLE AS
THIS ACTIVITY ARRIVES.
THE THUNDERSTORM POTENTIAL ON SUNDAY EARLY IN THE DAY WILL BE FROM
LINGERING ACTIVITY FROM THE OVERNIGHT. A BOUNDARY WILL MOVE
THROUGH IN THE MORNING AND WILL BRING DRIER AIR TO THE STATE.
TEMPERATURES SHOULD WARM IN TO THE 70S AND 80S BEHIND THE BOUNDARY
HOWEVER THUNDERSTORM CHANCES WILL BE LIMITED BY THE DRIER AIR. THE
BEST POTENTIAL FOR THUNDERSTORMS WILL BE ACROSS NORTHERN IOWA
DURING THE AFTERNOON IN CLOSER VICINITY TO THE UPPER LEVEL COLD
CORE. AN ATTENDANT HAIL THREAT WOULD BE POSSIBLE WITH ANY
AFTERNOON STORMS.
THE REMAINDER OF THE EXTENDED WILL BE COOL WITH 850 MB
TEMPERATURES IN THE 0-5C RANGE THROUGH WEDNESDAY. BREEZY AND COOL
CONDITIONS ON MONDAY. NOT EXPECTING ANY SHOWERS DESPITE THE
CYCLONIC FLOW WITH A GOOD INVERSION IN PLACE ABOVE THE BOUNDARY
LAYER. ANOTHER PUSH OF COOLER AIR TUESDAY NIGHT AND WEDNESDAY
ALONG WITH ANOTHER CHANCE FOR SHOWERS.
&&
.AVIATION...15/18Z
ISSUED AT 1234 PM CDT FRI MAY 15 2015
VSBYS UP ACROSS THE STATE WELL WITHIN VFR WILL REMAIN THROUGH THE
REMAINDER OF THE DAY. CIGS WILL CONTINUE TO HOVER AROUND VFR/MVFR
AT MOST LOCATIONS THROUGH TAF PERIOD. STORMS WILL MOVE THROUGH
OTM/DSM/FOD/ALO SITES THIS AFTERNOON/EVENING...TEMPORARILY
DROPPING CONDITIONS INTO MVFR AND IFR...AND EXITING ALL SITES BY
AROUND 03Z. EXPECT VSBYS TO DROP AGAIN OVERNIGHT WITH FOG...BUT
WILL HOLD OFF ON DROPPING VSBYS BELOW 1 MILE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CURTIS
LONG TERM...DONAVON
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1241 PM CDT FRI MAY 15 2015
...UPDATED AVIATION DISCUSSION...
.UPDATE...
ISSUED AT 958 AM CDT FRI MAY 15 2015
CLEANED UP GRIDS A BIT FROM THE FOG THIS MORNING AND ADJUSTED
SKY/TEMPS ACCORDINGLY. ALSO MAY SEE A BIT COOLER MAX TEMPS ACROSS
THE NORTH WITH SOME ADDED IN CIRRUS FROM A FEW POP UP
THUNDERSTORMS ACROSS NORTHWEST IOWA...SO ADJUSTED NORTHERN CWA
TEMPS DOWN A BIT. LINE OF STORMS ALREADY ACROSS ERN NE ON NOSE OF
THETA-E ADVECTION WHICH IS EXPECTED TO BE ORIENTED MORE INTO
SOUTHERN/WESTERN CWA BY THIS AFTERNOON. THEREFORE DID INCREASE
POPS A BIT IN THAT REGION AND ACROSS THE SOUTH FOR THIS EVENING.
&&
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/18Z
ISSUED AT 1234 PM CDT FRI MAY 15 2015
VSBYS UP ACROSS THE STATE WELL WITHIN VFR WILL REMAIN THROUGH THE
REMAINDER OF THE DAY. CIGS WILL CONTINUE TO HOVER AROUND VFR/MVFR
AT MOST LOCATIONS THROUGH TAF PERIOD. STORMS WILL MOVE THROUGH
OTM/DSM/FOD/ALO SITES THIS AFTERNOON/EVENING...TEMPORARILY
DROPPING CONDITIONS INTO MVFR AND IFR...AND EXITING ALL SITES BY
AROUND 03Z. EXPECT VSBYS TO DROP AGAIN OVERNIGHT WITH FOG...BUT
WILL HOLD OFF ON DROPPING VSBYS BELOW 1 MILE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BEERENDS
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
958 AM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 958 AM CDT FRI MAY 15 2015
CLEANED UP GRIDS A BIT FROM THE FOG THIS MORNING AND ADJUSTED
SKY/TEMPS ACCORDINGLY. ALSO MAY SEE A BIT COOLER MAX TEMPS ACROSS
THE NORTH WITH SOME ADDED IN CIRRUS FROM A FEW POP UP
THUNDERSTORMS ACROSS NORTHWEST IOWA...SO ADJUSTED NORTHERN CWA
TEMPS DOWN A BIT. LINE OF STORMS ALREADY ACROSS ERN NE ON NOSE OF
THETA-E ADVECTION WHICH IS EXPECTED TO BE ORIENTED MORE INTO
SOUTHERN/WESTERN CWA BY THIS AFTERNOON. THEREFORE DID INCREASE
POPS A BIT IN THAT REGION AND ACROSS THE SOUTH FOR THIS EVENING.
&&
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/12Z
ISSUED AT 643 AM CDT FRI MAY 15 2015
VSBYS FM FOG AND AREAS OF DENSE FOG WILL CONTINUE TO IMPROVE THROUGH
15Z. AFT 15Z WE SHOULD HAVE BKN VFR/MVFR CIGS INTO THE AFTERNOON.
A WARM FRONT WILL LIFT TO ABOUT HIGHWAY 20 THIS AFTERNOON. STORMS
WITH THIS FEATURE ARE NOT ANTICIPATED AT KDSM/OTM AND KFOD UNTIL AFT
21Z AND MAY NOT BE UNTIL AFT 00Z. SFC WIND WILL BE LGT AND VRB
BECOMING SOUTHERLY AROUND 10 KTS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...BEERENDS
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
644 AM CDT FRI MAY 15 2015
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/12Z
ISSUED AT 643 AM CDT FRI MAY 15 2015
VSBYS FM FOG AND AREAS OF DENSE FOG WILL CONTINUE TO IMPROVE THROUGH
15Z. AFT 15Z WE SHOULD HAVE BKN VFR/MVFR CIGS INTO THE AFTERNOON.
A WARM FRONT WILL LIFT TO ABOUT HIGHWAY 20 THIS AFTERNOON. STORMS
WITH THIS FEATURE ARE NOT ANTICIPATED AT KDSM/OTM AND KFOD UNTIL AFT
21Z AND MAY NOT BE UNTIL AFT 00Z. SFC WIND WILL BE LGT AND VRB
BECOMING SOUTHERLY AROUND 10 KTS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-CRAWFORD-
DALLAS-DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-
HARDIN-HUMBOLDT-JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-
MARSHALL-MONROE-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-
TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WRIGHT.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
359 AM CDT FRI MAY 15 2015
.SHORT TERM /TODAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
DENSE FOG HAS SPREAD OVER LOCATIONS THAT RECEIVED THE MOST RAINFALL
YESTERDAY BUT VISIBILITIES ARE ALREADY BEGINNING TO IMPROVE ACROSS
THE SOUTHWEST AND EASTERN FRINGES. THE HRRR HAS HANDLED THE DENSE
FOG LOCATION THE BEST AND AS SUCH I MADE SOME CHANGES TO THE
EXISTING ADVISORY...MAINLY TO EXTEND IT IN TIME FOR A COUPLE MORE
HOURS AND ALSO TO TRIM SOME FROM THE NORTHWEST AND AND EAST. THE
HRRR MODEL BEGINS TO ERODE THE FOG BY 14Z AND MODEL SOUNDINGS
SUPPORT A MUCH MORE SHALLOW MOIST LOW LEVEL BY THAT TIME SO WHILE I
FELT THE ADVISORY NEEDED TO BE EXTENDED...THE EVIDENT BREAKS IN THE
DENSE FOG MADE ME HESITANT TO EXTEND IT UNTIL 15Z.
BEYOND THE MORNING FOG...LOW PRESSURE DEVELOPING ON THE LEE SIDE OF
THE ROCKIES WILL LIFT TO THE NORTH NORTHEAST TODAY COLORADO INTO
NORTH DAKOTA. A WARM FRONT EXTENDING FROM THE LOW WILL LIFT ACROSS
IOWA FROM THE SOUTHWEST THIS MORNING REACHING A STORM LAKE TO
CHARITON LINE BY LATE AFTERNOON. WARM ADVECTION WILL OVERSPREAD THE
THE SOUTHWEST TWO THIRDS OF THE STATE THROUGH THE AFTERNOON. MODELS
HAVE US DESTABILIZING THROUGH THE MORNING BUT DEEP MOISTURE IS A
LITTLE PROBLEMATIC AND SHEAR DOES NOT LOOK PARTICULARLY ROBUST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE MORNING AND THROUGH
THIS AFTERNOON BUT THE THREAT OF SEVERE STORMS IS LIMITED BY THE
LACK OF STRONG SHEAR. THERE WILL BE SOME ELEVATED STORMS LIKELY IN
THE VICINITY OF THE FRONTAL BOUNDARY AND AN ISOLATED STORM WITH HAIL
CANNOT BE COMPLETELY RULED OUT BUT THE BEST INSTABILITY AND SEVERE
PARAMETERS REMAIN WEST OF THE CWA THROUGH 00Z. WE WILL BE
CONSIDERABLY WARMER TODAY WITH HIGHS WELL INTO THE 70S. THE CURRENT
FORECAST HAD TEMPS WELL TRENDED SO LITTLE CHANGES WERE MADE THERE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 359 AM CDT FRI MAY 15 2015
WARM FRONT WILL LIFT NORTHWARD FROM IOWA INTO MINNESOTA OVERNIGHT AS
SOUTHERLY FLOW DEEPENS ACROSS THE STATE. SOME ISOLATED TO SCATTERED
CONVECTION IS EXPECTED ALONG THE BOUNDARY OVERNIGHT AS IT LIFTS
NORTHWARD...ALTHOUGH OVERALL EXTENT WILL BE KEPT IN CHECK BY LITTLE
IF ANY SYNOPTIC LIFT. SOME OF THE STORM COULD BE QUITE STRONG GIVEN
THE INCREASING INSTABILITY BUT SHEAR REMAINS RELATIVELY WEAK AND
SHOULD LIMIT OVERALL LONGEVITY AND INTENSITY OF ANY STORMS. THE
WARM SECTOR WILL BE IN PLACE ACROSS IOWA ON SATURDAY WITH STRONG
SOUTH WINDS. WILL BEGIN TO SEE AN INCREASE IN SYNOPTIC FORCING BY
LATER IN THE DAY AS SHORTWAVE ROUNDS BASE OF WESTERN TROF AND BEGINS
TO HEAD NORTHEAST. HAVE INCREASED POPS ACRS THE WEST BY LATE
AFTERNOON WITH BULK OF STORMS/PCPN ARRIVING LATE SATURDAY NIGHT WITH
APPROACH OF UPPER SYSTEM. THIS WILL BE THE BEST THREAT FOR HEAVIER
PRECIPITATION AND SEVERE WEATHER ALTHOUGH TIMING IS BECOMING SUCH
THAT THE OVERALL SEVERE WEATHER THREAT MAY BECOME LIMITED GIVEN TIME
OF DAY. DRY SLOT OVERSPREAD THE STATE ON SUNDAY WITH PRECIPITATION
THREAT DIMINISHING IN MOST AREAS BY AFTERNOON. MAY SEE A BRIEF
THREAT OF MORE STORMS TOWARD MIDDAY IN THE FAR EAST AND NORTH WITH
FROPA BUT THE BULK OF STORMS WILL BE FARTHER EAST ON SUNDAY.
COLD ADVECTION INCREASES SUNDAY NIGHT INTO MONDAY WITH WINDY AND
COOL CONDITIONS. THERE WILL BE LITTLE THREAT FOR PRECIPITATION
EARLY NEXT WEEK WITH AREA UNDER THE INFLUENCE OF CANADIAN HIGH
PRESSURE AND A DRY AIRMASS. THE NEXT BEST THREAT OF PRECIPITATION WILL
ARRIVE LATE TUESDAY NIGHT INTO WEDNESDAY AS SYSTEM APPROACHES THE
STATE FROM THE SOUTHWEST. HOWEVER...THIS SYSTEM WILL BE SHEARING
OUT WITH TIME WITH LIFT WEAKENING AND PRECIPITATION REMAINING
LIGHT. TEMPERATURES WILL REMAIN AT OR BELOW NORMAL INTO THE MIDDLE
OF THE WEEK.
&&
.AVIATION...15/06Z
ISSUED AT 1205 AM CDT FRI MAY 15 2015
DENSE FOG WILL CONTINUE TO PROVIDE LIFR CIGS AND VIS THROUGHOUT
THE OVERNIGHT HOURS. FOD/MCW/ALO LIKELY WILL SEE THE WORST
FOG/STRATUS CONDITIONS BUT CANNOT RULE OUT DSM RECEIVING SOME
PERIODIC ONE HALF MILE VIS OVERNIGHT. CONDITIONS IMPROVE BY
SUNRISE FRIDAY MORNING...BUT MVFR STRATUS DECK REMAINS THROUGH
THE AFTERNOON.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-CRAWFORD-
DALLAS-DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-
HARDIN-HUMBOLDT-JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-
MARSHALL-MONROE-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-
TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WRIGHT.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1038 PM CDT SAT MAY 16 2015
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 1035 PM CDT SAT MAY 16 2015
WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
TROUGH OF LOW PRESSURE LIFTING NORTHEAST ACROSS THE WESTERN HIGH
PLAINS. MEANWHILE, WEAK UPPER LEVEL RIDGING IS MOVING EASTWARD
ACROSS THE DESERT SOUTHWEST. NEAR THE SURFACE, A BROAD AREA OF LOW
PRESSURE EXTENDS FROM WESTERN NEBRASKA SOUTHWARD INTO EXTREME
EASTERN COLORADO.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 128 PM CDT SAT MAY 16 2015
ABBREVIATED SHORT TERM WITH MET WATCH. MADE ADJUSTMENTS TO POPS
CONCERNING THE NON SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL
KANSAS EARLY THIS AFTERNOON. SOME OF THE ACTIVITY ACROSS OKLAHOMA
HAS BEEN INCREASING IN INTENSITY, SO WILL HAVE TO WATCH OUT FOR
MARGINALLY SEVERE BASICALLY SE OF A LINE FROM ASHLAND TO ST JOHN.
THE NEXT AREA OF CONCERN IS OUT WEST. BUBBLING CUMULUS HAS BEEN
NOTED ON VIS SAT. TOOK A BLEND OF THE HRRR AND WRF-ARW FOR POP
ARRANGEMENTS WITH THIS ACTIVITY. WE LAUNCHED AN 18Z RAOB, WHICH
LOOKS FAR FROM SPECTACULAR. FIRST, INSTABILITY IS OBVIOUSLY VERY
LIMITED WITH ALL LINGERING CLOUD COVER. SECOND, 850-HPA WINDS ARE
VERY WEAK. IN FACT, THE ENTIRE LOW LEVELS ARE WEAK, ALTHOUGH
THERE IS DECENT VEERING. THIRDLY, UPPER LEVEL WINDS ARE BACKED.
TRANSLATION: MESSY HP SUPERCELLS. SO THE SITUATION HAS CHANGED A
BIT FROM PREVIOUSLY THOUGHT. THE MORNING SHOWERS AND THUNDERSTORMS
WILL PROBABLY HAVE DELETERIOUS IMPACTS TO STORM INTENSITY. RAP
ANALYSIS DOES SHOW CAPE INCREASING OUT WEST. STILL THINK WE WILL
STILL SEE SEVERE. THINK TORNADO POTENTIAL IS NOT AS HIGH AS
PREVIOUSLY THOUGH. THERE IS ENOUGH SHEAR TO GET ROTATING STORMS
THOUGH AND A FEW TORNADOES ARE NOT OUT OF THE QUESTION. WHAT IS
IN QUESTION IS IF THE TORNADOES WILL BE STRONG OR NOT. HAVE SEEN
AN UPTICK ON UPDRAFT HELICITY RECENTLY, SO SOMETHING TO MONITOR.
FROM THE 18Z RAOB, IT WILL TAKE QUITE THE ATMOSPHERIC TURN OVER
TO GET IT PRIMED FOR STRONG TORNADOES WITH DECENT INSTABILITY AND
STRENGTHENING LOW LEVEL WINDS. THERE IS SOME CONCERN ACROSS SOUTH-
CENTRAL KANSAS THAT LOW LEVEL WINDS THIS EVENING WILL STRENGTHEN
AND THE TORNADO POTENTIAL COULD GO UP. BUT BY THAT TIME, THE
STORMS COULD BE OUTFLOWY, PRECIPITATION LADEN MESSY STORMS. WILL
CONTINUE TO MONITOR THE MESOSCALE SITUATION AND ADJUST AS
NECESSARY. STORMS WILL BE MOVING AT A GOOD CLIP TOO.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 156 PM CDT SAT MAY 16 2015
THE SOUTHERN BRANCH OF THE WESTERLIES WILL CONTINUE TO BE ACTIVE
WITH AMPLIFICATION RESULTING FROM TROPICAL CONVECTION ACROSS THE
WESTERN PACIFIC. SUNDAY AND MONDAY WILL BE BETWEEN SYSTEMS AND THE
ONLY FORECAST CHALLENGE WILL BE TEMPERATURES AS ACTIVELY GROWING
VEGETATION AND WET SOILS WILL IMPACT TEMPERATURES.
THE NORTHERN BRANCH OF THE WESTERLIES WILL ALLOW SFC HIGH
PRESSURE TO BUILD INTO THE AREA MONDAY. WITH THE APPROACH OF
ANOTHER S/WV TROUGH IN THE SOUTHERN BRANCH, THE MOIST BOUNDARY
LAYER AIR SHOULD BE MOVING BACK NORTHWEST INTO THE HIGHER TERRAIN.
WIDESPREAD CONVECTION SHOULD RESULT BY TUESDAY AND INTO WEDNESDAY.
YET ANOTHER SYSTEM IS EXPECTED TOWARDS NEXT WEEKEND WITH
ADDITIONAL PCPN EXPECTED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 656 PM CDT SAT MAY 16 2015
THE AREA WILL REMAIN CONVECTIVELY ACTIVE THROUGH EARLY EVENING, AT
LEAST FOR DDC AND HYS, BEFORE ALL LINEAR MODE CONVECTION EXITS THE
REGION. HEAVY RAIN AND BRIEF IFR VISIBITY HAS BEEN COMMON IN THE
STRONGEST STORMS WITH GEEANRALLY JUST SUB SEVERE SURFACE WINDS. BY
OVERNIGHT THE WESTERLY WINDS WILL BEGIN TO DEVELOP ACROSS THE AREA
WITH VFR CONDITIONS EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 82 49 70 / 40 0 0 10
GCK 49 80 47 69 / 10 0 0 0
EHA 48 79 47 69 / 10 0 0 0
LBL 49 81 50 73 / 10 0 0 0
HYS 52 80 48 67 / 60 0 0 0
P28 54 83 54 76 / 70 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...SUGDEN
LONG TERM...HUTTON
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
659 PM CDT SAT MAY 16 2015
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 128 PM CDT SAT MAY 16 2015
ABBREVIATED SHORT TERM WITH MET WATCH. MADE ADJUSTMENTS TO POPS
CONCERNING THE NON SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL
KANSAS EARLY THIS AFTERNOON. SOME OF THE ACTIVITY ACROSS OKLAHOMA
HAS BEEN INCREASING IN INTENSITY, SO WILL HAVE TO WATCH OUT FOR
MARGINALLY SEVERE BASICALLY SE OF A LINE FROM ASHLAND TO ST JOHN.
THE NEXT AREA OF CONCERN IS OUT WEST. BUBBLING CUMULUS HAS BEEN
NOTED ON VIS SAT. TOOK A BLEND OF THE HRRR AND WRF-ARW FOR POP
ARRANGEMENTS WITH THIS ACTIVITY. WE LAUNCHED AN 18Z RAOB, WHICH
LOOKS FAR FROM SPECTACULAR. FIRST, INSTABILITY IS OBVIOUSLY VERY
LIMITED WITH ALL LINGERING CLOUD COVER. SECOND, 850-HPA WINDS ARE
VERY WEAK. IN FACT, THE ENTIRE LOW LEVELS ARE WEAK, ALTHOUGH
THERE IS DECENT VEERING. THIRDLY, UPPER LEVEL WINDS ARE BACKED.
TRANSLATION: MESSY HP SUPERCELLS. SO THE SITUATION HAS CHANGED A
BIT FROM PREVIOUSLY THOUGHT. THE MORNING SHOWERS AND THUNDERSTORMS
WILL PROBABLY HAVE DELETERIOUS IMPACTS TO STORM INTENSITY. RAP
ANALYSIS DOES SHOW CAPE INCREASING OUT WEST. STILL THINK WE WILL
STILL SEE SEVERE. THINK TORNADO POTENTIAL IS NOT AS HIGH AS
PREVIOUSLY THOUGH. THERE IS ENOUGH SHEAR TO GET ROTATING STORMS
THOUGH AND A FEW TORNADOES ARE NOT OUT OF THE QUESTION. WHAT IS
IN QUESTION IS IF THE TORNADOES WILL BE STRONG OR NOT. HAVE SEEN
AN UPTICK ON UPDRAFT HELICITY RECENTLY, SO SOMETHING TO MONITOR.
FROM THE 18Z RAOB, IT WILL TAKE QUITE THE ATMOSPHERIC TURN OVER
TO GET IT PRIMED FOR STRONG TORNADOES WITH DECENT INSTABILITY AND
STRENGTHENING LOW LEVEL WINDS. THERE IS SOME CONCERN ACROSS SOUTH-
CENTRAL KANSAS THAT LOW LEVEL WINDS THIS EVENING WILL STRENGTHEN
AND THE TORNADO POTENTIAL COULD GO UP. BUT BY THAT TIME, THE
STORMS COULD BE OUTFLOWY, PRECIPITATION LADEN MESSY STORMS. WILL
CONTINUE TO MONITOR THE MESOSCALE SITUATION AND ADJUST AS
NECESSARY. STORMS WILL BE MOVING AT A GOOD CLIP TOO.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 156 PM CDT SAT MAY 16 2015
THE SOUTHERN BRANCH OF THE WESTERLIES WILL CONTINUE TO BE ACTIVE
WITH AMPLIFICATION RESULTING FROM TROPICAL CONVECTION ACROSS THE
WESTERN PACIFIC. SUNDAY AND MONDAY WILL BE BETWEEN SYSTEMS AND THE
ONLY FORECAST CHALLENGE WILL BE TEMPERATURES AS ACTIVELY GROWING
VEGETATION AND WET SOILS WILL IMPACT TEMPERATURES.
THE NORTHERN BRANCH OF THE WESTERLIES WILL ALLOW SFC HIGH
PRESSURE TO BUILD INTO THE AREA MONDAY. WITH THE APPROACH OF
ANOTHER S/WV TROUGH IN THE SOUTHERN BRANCH, THE MOIST BOUNDARY
LAYER AIR SHOULD BE MOVING BACK NORTHWEST INTO THE HIGHER TERRAIN.
WIDESPREAD CONVECTION SHOULD RESULT BY TUESDAY AND INTO WEDNESDAY.
YET ANOTHER SYSTEM IS EXPECTED TOWARDS NEXT WEEKEND WITH
ADDITIONAL PCPN EXPECTED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 656 PM CDT SAT MAY 16 2015
THE AREA WILL REMAIN CONVECTIVELY ACTIVE THROUGH EARLY EVENING, AT
LEAST FOR DDC AND HYS, BEFORE ALL LINEAR MODE CONVECTION EXITS THE
REGION. HEAVY RAIN AND BRIEF IFR VISIBITY HAS BEEN COMMON IN THE
STRONGEST STORMS WITH GEEANRALLY JUST SUB SEVERE SURFACE WINDS. BY
OVERNIGHT THE WESTERLY WINDS WILL BEGIN TO DEVELOP ACROSS THE AREA
WITH VFR CONDITIONS EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 82 49 70 / 90 0 0 10
GCK 50 80 47 69 / 70 0 0 0
EHA 48 79 47 69 / 40 0 0 0
LBL 50 81 50 73 / 50 0 0 0
HYS 53 80 48 67 / 90 0 0 0
P28 56 83 54 76 / 90 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...HUTTON
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
147 PM CDT FRI MAY 15 2015
...UPDATED SHORT TERM AND LONG TERM DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 141 PM CDT FRI MAY 15 2015
RAP AND NGM BOTH SUPPORTING A SURFACE BOUNDARY EXTENDING FROM
NEAR HAYS TO COLDWATER AT 00Z SATURDAY WITH WEAK 0-1KM MOISTURE
CONVERGENCE OCCURRING ALONG THIS BOUNDARY. 0-6KM SHEAR IN THIS
AREA WILL BE FROM 20 TO 25 KNOTS AND CAPE VALUES ARE EXPECTED TO
RANGE FROM 1000 TO 1500 J/KG. RAP HAS SOME CIN REMAINING IN THIS
AREA GIVEN THE WARM MID LEVEL TEMPERATURES WHILE THE NAM SUGGESTS
A FEW ISOLATED THUNDERSTORMS BEING POSSIBLE. AT THIS TIME GIVEN
THE CU DEVELOPING WILL RETAIN MENTION OF ISOLATED THUNDERSTORMS
GOING ALONG AND EAST OF THIS BOUNDARY EARLY TONIGHT. ANOTHER AREA
OF THUNDERSTORMS WILL DEVELOP EARLY THIS EVENING NEAR THE COLORADO
BORDER. THIS AREA WILL HAVE MORE FAVORABLE UPPER LEVEL DYNAMICS
ALONG WITH IMPROVING WARM AIR ADVECTION NEAR THE NOSE OF A 50 KNOT
850MB JET BASED ON THE 12Z NAM. THESE STORMS WILL MARCH EAST
ACROSS WESTERN KANSAS OVERNIGHT WITH A FEW OF THESE STORMS BEING
CAPABLE OF PRODUCING SMALL HAIL AND WIND GUSTS OF UP TO 55 MPH.
BY EARLY SATURDAY MORNING THIS THUNDERSTORM ACTIVITY WILL BE MOVE
INTO CENTRAL KANSAS AS AN UPPER LEVEL TROUGH CROSSES EASTERN
COLORADO AND NORTHEAST NEW MEXICO. 12Z NAM SHOWING 0-6KM SHEAR
SATURDAY AFTERNOON RANGING FROM 40 TO NEAR 50 KNOTS AND CAPE
VALUES WILL RANGING FROM 1500 TO 2500 J/KG AHEAD OF THIS
UPPER LEVEL SYSTEM. THIS CONTINUES TO SUPPORT THE CHANCE FOR
SEVERE THUNDERSTORMS ALONG AND EAST OF WHERE THIS DRY LINE WILL BE
LOCATED BETWEEN 18Z AND 21Z SATURDAY. LARGE HAIL AND STRONG
DAMAGING WINDS CURRENTLY APPEARS TO BE THE MAIN HAZARD ALONG WITH
PERIODS OF HEAVY RAINFALL. A FEW TORNADOES WILL ALSO BE POSSIBLE
LATE SATURDAY AND EARLY SATURDAY NIGHT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 141 PM CDT FRI MAY 15 2015
EVENING CONVECTION WILL TAPER OFF EARLY SATURDAY NIGHT AS THE
UPPER LEVEL TROUGH LIFTS NORTHEAST INTO NORTH CENTRAL KANSAS AND
THE DRY LINE/COLD FRONT MOVES SOUTH AND EAST. WESTERLY DOWNSLOPE
FLOW WILL DEVELOP BY EARLY SUNDAY MORNING AND CONTINUE THROUGH THE
REMAINDER OF THE WEEKEND AS ANOTHER UPPER LEVEL TROUGH MOVES OUT
OF SOUTHERN WYOMING AND INTO THE CENTRAL HIGH PLAINS. 700MB TO
500MB LAPSE RATES WILL VARY FROM 7 TO 8C/KM AHEAD OF THIS UPPER
WAVE, HOWEVER MOISTURE APPEARS SOMEWHAT LIMITED EARLY SUNDAY
NIGHT. ALTHOUGH A FEW SPRINKLE MAY BE POSSIBLE NEAR AND NORTH OF
THE INTERSTATE 70 CORRIDOR, AT THIS TIME WILL ONLY INCREASE CLOUD
COVER AT THIS TIME SUNDAY EVENING GIVEN THE LIMITED MOISTURE IN
THE LOWER LEVELS.
GIVEN THE WESTERLY DOWNSLOPE FLOW AND 850MB TEMPERATURES AT 00Z
MONDAY WILL RANGING FROM 18C TO NEAR 24C THE PREVIOUS FORECAST
STILL LOOKS ON TRACK WITH HIGHS RANGING FROM THE UPPER 70S IN WEST
CENTRAL KANSAS TO THE LOWER 80S IN SOUTH CENTRAL KANSAS.
EARLY NEXT WEEK AN UPPER LEVEL RIDGE AXIS WILL CROSS WESTERN
KANSAS AS AN AREA OF HIGH PRESSURE AT THE SURFACE BUILDS INTO
KANSAS PLAINS. TEMPERATURES ON MONDAY WILL AVERAGE AROUND 10F
COOLER WHEN COMPARED TO THE HIGHS ON SUNDAY GIVEN THE 900 TO
850MB TEMPERATURE TRENDS FROM 00Z MONDAY AND 00Z TUESDAY.
CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS AN UPPER LEVEL
TROUGH/LOW MOVES EAST ACROSS THE SOUTHWEST UNITED STATES. IN
ADDITION TO THE INCREASING CLOUDS THERE WILL ALSO BE A CHANCE FOR
PRECIPITATION TO DEVELOP BY EARLY TUESDAY GIVEN A MOIST
SOUTHEASTERLY UPSLOPE FLOW, WARM AIR ADVECTION, AND IMPROVING
ISENTROPIC LIFT ACROSS SOUTHWEST KANSAS. HIGH PRECIPITATION
CHANCES WILL CONTINUE THROUGH MID WEEK AS THE UPPER LEVEL SYSTEM
WEAKENS AND MOVES EAST NORTHEAST INTO THE CENTRAL PLAINS.
TEMPERATURES THROUGH MID WEEK WILL STAY ON THE COOL SIDE GIVEN THE
CLOUD COVER AND HIGH PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1225 PM CDT FRI MAY 15 2015
A WEAK SURFACE BOUNDARY WILL MOVE INTO EASTERN KANSAS BY LATE DAY
AND THIS WILL BE THE PRIMARY AREA OF FOCUS FOR ANY THUNDERSTORM
DEVELOPMENT BETWEEN 21Z FRIDAY AND 03Z SATURDAY. BASED ON THE
LATEST NAM THIS CONVECTION WILL STAY EAST OF ALL THREE TAF SITES
LATE THIS AFTERNOON AND EARLY TONIGHT. ANOTHER AREA OF CONVECTION
WILL DEVELOP BY EARLY THIS EVENING NEAR A TROUGH OF LOW PRESSURE
AT THE SURFACE OVER FAR EASTERN COLORADO. AS THESE STORMS IN
EASTERN COLORADO DEVELOP THEY WILL MOVE ACROSS WESTERN KANSAS
OVERNIGHT. AT THIS TIME THE BETTER CHANCE FOR CONVECTION WILL
OCCUR IN THE GCK AREA AROUND 06Z AND DDC AND HYS BETWEEN 09Z AND
12Z SATURDAY. AS THE CONVECTION MOVES EAST ACROSS WESTERN KANSAS
THE 12Z NAM BUFR SOUNDINGS INDICATE AN AREA OF LOW LEVEL MOISTURE
WILL INCREASE AS A SOUTH SOUTHEAST FLOW CONTINUES AT AROUND 15
KNOTS IN THE SURFACE TO 800MB LEVEL. GIVEN THE EXPECTED WIND
SPEEDS DENSE FOG IS NOT EXPECTED, HOWEVER LOW MVFR CEILINGS WILL
BE POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 64 78 53 80 / 60 60 50 0
GCK 61 80 51 78 / 50 30 30 0
EHA 55 76 49 77 / 40 30 20 0
LBL 62 80 51 80 / 50 30 30 0
HYS 64 77 54 78 / 50 60 50 0
P28 65 78 58 81 / 50 70 70 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1232 PM CDT Fri May 15 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 328 AM CDT FRI MAY 15 2015
A broad upper level low was slowly pushing east across southern CA
into southwest AZ. A minor lead upper level trough was lifting
northeast across west TX into western OK. This trough was providing
ascent for a complex of thunderstorms to develop across southwest OK
and west central TX early this morning. This lead upper level trough
will lift northeast into northeast OK and southeast KS later this
morning.
A lee surface trough was deepening across the central and southern
high plains. Southerly 850mb winds were advecting deeper moisture
northward across central and west central KS. The isentropic lift
was deep enough for elevated storms to develop across north central
KS. These storms were lifting north-northeast and may develop
eastward into the western counties of the CWA through the mid
morning hours. The stronger storms may produce small hail.
The GFS, RAP and WRF models show the minor wave over west central
TX/southwest OK lifting northeast and providing enough ascent along
with the deeper moisture return for scattered showers and
thunderstorms to develop across the southern counties of the CWA
during the late morning hours, and spreading northeast across east
central and northeast KS during the early afternoon hours. However
the NAM12 and HRRR show most of the the thunderstorms remaining
across the western and northern counties of the CWA this morning. I
went with chance pops across the western and southern counties this
morning with chance pops across the northeast counties this
afternoon. The vertical wind shear Today looks rather weak with only
20 to 30 KTS of SFC to 6KM effective shear across the CWA. Several
numerical models show 1500-2000 J/KG of MLCAPE developing across the
CWA, thus some of the thunderstorms this afternoon across the
northern half of the CWA may be strong to marginally severe this
afternoon. The primary hazards would be penny to quarter hail and 50
to 60 MPH wind gusts. Highs Today will range from the upper 70s to
lower 80s with mostly cloudy skies.
Tonight, the amplified upper level low will move east across UT and
the four corners region. A strong mid level jet max will move
northeast across NM into eastern CO. The minor H5 trough across
southeast KS and southwest MO this afternoon will move northeast
across central MO. The intense isentropic lift will develop
northward across the northern plains and upper Midwest. The CWA will
remain dry through most of the night. Stronger ascent across western
KS will cause elevated thunderstorms to develop late tonight. Some
of these thunderstorms may move into the western counties of the CWA
before day break. These elevated storms may be strong to severe with
the primary hazard being large hail. Overnight lows will only drop
into the mid 60s.
.LONG TERM...(Saturday through Thursday)
Issued at 328 AM CDT FRI MAY 15 2015
Forecast focus remains on impact of intense upper system that will
emerge into the Plains Saturday into Saturday night.
All models appear to be converging on the most likely scenario on
Saturday which is that severe thunderstorms will develop near and
east of a dryline from Dodge City north toward Goodland after 20z
Saturday. Storms will quickly intensify and race NE at 50 to 60
mph which could bring them into parts of central Kansas by 6pm to
7pm Saturday. If sufficient buoyancy/instability is present...low level
shear and deep shear of 20-30kts and 50-60kts respectively would
provide an environment capable of supporting all manner of hazards
with the storms.
The wild card in this forecast remains how much
morning elevated convection will develop across OK into KS. We
continue to see a signal from various models that some convection
will develop Saturday morning within the weakly capped warm
sector. This is plausible since forcing will increase in advance
of the upper trough so we could see some impact on destabilization
across parts of the area through midday if this occurs. This makes
the scenario on Saturday difficult to pin down at this point with
regard to magnitude of the risk. In any case...forcing...shear
profiles and potential instability suggest this has the potential
to be a high impact event for parts of the area Saturday evening
and will highlight that everyone needs to monitor this especially
given all of the outdoor activities this weekend.
The dry slot will work into the area Sunday with gusty southwest
winds and warm temps. Instability axis should shift east of the
area so will keep conds dry on Sunday pm. The cold front will
sweep through the area Sunday night bringing much cooler and drier
air into the area for Monday and Tues. Only a brief break before
the next wave will move into the region with more rain expected
for later Tues into early Thurs. Trends suggest that the
severe risk with this system should stay south of the area so look
for another widespread rain with isolated thunder with this system.
&&
.AVIATION...(For the 18Z TAFs through 18Z Saturday Afternoon)
Issued at 1231 PM CDT FRI MAY 15 2015
Storms moving through the area this morning have pushed north of the
terminals, although some light rain may still be seen at TOP/FOE
within the next hour. Have left VCTS for this afternoon since there
is still a chance for some isolated storms. Ceilings should lift
behind this rain leaving VFR conditions at all sites until early
tomorrow morning. Between 06-08Z, sites are expected to drop to
MVFR, although IFR is possible for brief periods of time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS TOPEKA KS
642 AM CDT Fri May 15 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 328 AM CDT FRI MAY 15 2015
A broad upper level low was slowly pushing east across southern CA
into southwest AZ. A minor lead upper level trough was lifting
northeast across west TX into western OK. This trough was providing
ascent for a complex of thunderstorms to develop across southwest OK
and west central TX early this morning. This lead upper level trough
will lift northeast into northeast OK and southeast KS later this
morning.
A lee surface trough was deepening across the central and southern
high plains. Southerly 850mb winds were advecting deeper moisture
northward across central and west central KS. The isentropic lift
was deep enough for elevated storms to develop across north central
KS. These storms were lifting north-northeast and may develop
eastward into the western counties of the CWA through the mid
morning hours. The stronger storms may produce small hail.
The GFS, RAP and WRF models show the minor wave over west central
TX/southwest OK lifting northeast and providing enough ascent along
with the deeper moisture return for scattered showers and
thunderstorms to develop across the southern counties of the CWA
during the late morning hours, and spreading northeast across east
central and northeast KS during the early afternoon hours. However
the NAM12 and HRRR show most of the the thunderstorms remaining
across the western and northern counties of the CWA this morning. I
went with chance pops across the western and southern counties this
morning with chance pops across the northeast counties this
afternoon. The vertical wind shear Today looks rather weak with only
20 to 30 KTS of SFC to 6KM effective shear across the CWA. Several
numerical models show 1500-2000 J/KG of MLCAPE developing across the
CWA, thus some of the thunderstorms this afternoon across the
northern half of the CWA may be strong to marginally severe this
afternoon. The primary hazards would be penny to quarter hail and 50
to 60 MPH wind gusts. Highs Today will range from the upper 70s to
lower 80s with mostly cloudy skies.
Tonight, the amplified upper level low will move east across UT and
the four corners region. A strong mid level jet max will move
northeast across NM into eastern CO. The minor H5 trough across
southeast KS and southwest MO this afternoon will move northeast
across central MO. The intense isentropic lift will develop
northward across the northern plains and upper Midwest. The CWA will
remain dry through most of the night. Stronger ascent across western
KS will cause elevated thunderstorms to develop late tonight. Some
of these thunderstorms may move into the western counties of the CWA
before day break. These elevated storms may be strong to severe with
the primary hazard being large hail. Overnight lows will only drop
into the mid 60s.
.LONG TERM...(Saturday through Thursday)
Issued at 328 AM CDT FRI MAY 15 2015
Forecast focus remains on impact of intense upper system that will
emerge into the Plains Saturday into Saturday night.
All models appear to be converging on the most likely scenario on
Saturday which is that severe thunderstorms will develop near and
east of a dryline from Dodge City north toward Goodland after 20z
Saturday. Storms will quickly intensify and race NE at 50 to 60
mph which could bring them into parts of central Kansas by 6pm to
7pm Saturday. If sufficient buoyancy/instability is present...low level
shear and deep shear of 20-30kts and 50-60kts respectively would
provide an environment capable of supporting all manner of hazards
with the storms.
The wild card in this forecast remains how much
morning elevated convection will develop across OK into KS. We
continue to see a signal from various models that some convection
will develop Saturday morning within the weakly capped warm
sector. This is plausible since forcing will increase in advance
of the upper trough so we could see some impact on destabilization
across parts of the area through midday if this occurs. This makes
the scenario on Saturday difficult to pin down at this point with
regard to magnitude of the risk. In any case...forcing...shear
profiles and potential instability suggest this has the potential
to be a high impact event for parts of the area Saturday evening
and will highlight that everyone needs to monitor this especially
given all of the outdoor activities this weekend.
The dry slot will work into the area Sunday with gusty southwest
winds and warm temps. Instability axis should shift east of the
area so will keep conds dry on Sunday pm. The cold front will
sweep through the area Sunday night bringing much cooler and drier
air into the area for Monday and Tues. Only a brief break before
the next wave will move into the region with more rain expected
for later Tues into early Thurs. Trends suggest that the
severe risk with this system should stay south of the area so look
for another widespread rain with isolated thunder with this system.
&&
.AVIATION...(For the 12Z TAFs through 12Z Saturday Morning)
Issued at 640 AM CDT FRI MAY 15 2015
Patchy fog has been noted at FOE/TOP this morning, so have opted to
keep a tempo group with lower visbys until winds pick up around
15Z. Have included VCTS at all sites beginning later this morning
until 00Z, however, confidence with the exact timing/location of
these storms is low. There is another chance for lower
ceilings/visibilities tomorrow morning.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS TOPEKA KS
359 AM CDT Fri May 15 2015
.SHORT TERM...(Today and Tonight)
Issued at 328 AM CDT FRI MAY 15 2015
A broad upper level low was slowly pushing east across southern CA
into southwest AZ. A minor lead upper level trough was lifting
northeast across west TX into western OK. This trough was providing
ascent for a complex of thunderstorms to develop across southwest OK
and west central TX early this morning. This lead upper level trough
will lift northeast into northeast OK and southeast KS later this
morning.
A lee surface trough was deepening across the central and southern
high plains. Southerly 850mb winds were advecting deeper moisture
northward across central and west central KS. The isentropic lift
was deep enough for elevated storms to develop across north central
KS. These storms were lifting north-northeast and may develop
eastward into the western counties of the CWA through the mid
morning hours. The stronger storms may produce small hail.
The GFS, RAP and WRF models show the minor wave over west central
TX/southwest OK lifting northeast and providing enough ascent along
with the deeper moisture return for scattered showers and
thunderstorms to develop across the southern counties of the CWA
during the late morning hours, and spreading northeast across east
central and northeast KS during the early afternoon hours. However
the NAM12 and HRRR show most of the the thunderstorms remaining
across the western and northern counties of the CWA this morning. I
went with chance pops across the western and southern counties this
morning with chance pops across the northeast counties this
afternoon. The vertical wind shear Today looks rather weak with only
20 to 30 KTS of SFC to 6KM effective shear across the CWA. Several
numerical models show 1500-2000 J/KG of MLCAPE developing across the
CWA, thus some of the thunderstorms this afternoon across the
northern half of the CWA may be strong to marginally severe this
afternoon. The primary hazards would be penny to quarter hail and 50
to 60 MPH wind gusts. Highs Today will range from the upper 70s to
lower 80s with mostly cloudy skies.
Tonight, the amplified upper level low will move east across UT and
the four corners region. A strong mid level jet max will move
northeast across NM into eastern CO. The minor H5 trough across
southeast KS and southwest MO this afternoon will move northeast
across central MO. The intense isentropic lift will develop
northward across the northern plains and upper Midwest. The CWA will
remain dry through most of the night. Stronger ascent across western
KS will cause elevated thunderstorms to develop late tonight. Some
of these thunderstorms may move into the western counties of the CWA
before day break. These elevated storms may be strong to severe with
the primary hazard being large hail. Overnight lows will only drop
into the mid 60s.
.LONG TERM...(Saturday through Thursday)
Issued at 328 AM CDT FRI MAY 15 2015
Forecast focus remains on impact of intense upper system that will
emerge into the Plains Saturday into Saturday night.
All models appear to be converging on the most likely scenario on
Saturday which is that severe thunderstorms will develop near and
east of a dryline from Dodge City north toward Goodland after 20z
Saturday. Storms will quickly intensify and race NE at 50 to 60
mph which could bring them into parts of central Kansas by 6pm to
7pm Saturday. If sufficient buoyancy/instability is present...low level
shear and deep shear of 20-30kts and 50-60kts respectively would
provide an environment capable of supporting all manner of hazards
with the storms.
The wild card in this forecast remains how much
morning elevated convection will develop across OK into KS. We
continue to see a signal from various models that some convection
will develop Saturday morning within the weakly capped warm
sector. This is plausible since forcing will increase in advance
of the upper trough so we could see some impact on destabilization
across parts of the area through midday if this occurs. This makes
the scenario on Saturday difficult to pin down at this point with
regard to magnitude of the risk. In any case...forcing...shear
profiles and potential instability suggest this has the potential
to be a high impact event for parts of the area Saturday evening
and will highlight that everyone needs to monitor this especially
given all of the outdoor activities this weekend.
The dry slot will work into the area Sunday with gusty southwest
winds and warm temps. Instability axis should shift east of the
area so will keep conds dry on Sunday pm. The cold front will
sweep through the area Sunday night bringing much cooler and drier
air into the area for Monday and Tues. Only a brief break before
the next wave will move into the region with more rain expected
for later Tues into early Thurs. Trends suggest that the
severe risk with this system should stay south of the area so look
for another widespread rain with isolated thunder with this system.
&&
.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1122 PM CDT THU MAY 14 2015
Mostly clear skies and light winds have led to near saturation
across the area by 11 PM. However, winds should increase and
higher clouds should thicken decreasing chances for dense fog
overnight. Can`t rule out the possibility for showers or
thunderstorms developing later tonight into the morning hours.
However, chances are low enough that have not included them in
TAF. Southerly winds will pick up during the day with gusts in the
afternoon. Another low chance of thunderstorms is possible this
evening.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
657 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 657 PM CDT SAT MAY 16 2015
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 208 PM CDT SAT MAY 16 2015
LOCALLY HEAVY RAIN IN PARTS OF WEST KY WITH AMOUNTS SINCE MIDNIGHT
1-2" IN A FEW SPOTS...MOSTLY AT OR BELOW 1". AREAL FLOOD
ADVISORIES WILL SUFFICE GIVEN THE PROGRESSIVE NATURE OF THE
ACTIVITY AND THE DOWNWARD TREND EXPECTED OVERALL. LITTLE TO NO
LIGHTNING...DEFINITELY EFFICIENT NONE THE LESS GIVEN WEAK LAPSE
RATES AND SMALL CAPE. ALL THE MODELS POINT TO A DIMINISHING TREND
FOR THE OVERNIGHT IN THE WAKE OF THIS WAVE THAT WE HAVE MONITORED
ON WVAPOR MOVING SLOWLY NE. THE RAP AND NAM WERE GENERALLY
FOLLOWED. WE CONTINUE TO HOLD TEMPS DOWN THE REST OF TODAY AS
WELL. THEY SHOULD FALL LITTLE TONIGHT WITH THE STAGNANT/HUMID
AIRMASS IN PLACE AND SOUTHERLY FLOW THE RULE.
SPC EXPANDED THEIR SLIGHT RISK AREA EAST DAY 2 INTO 1/2 OF THE
AREA FROM THE WEST. THIS SEEMS OVERDONE AND TEND TO DISAGREE. SURE
THERE COULD BE A FEW WARNINGS. BUT ENOUGH QUESTION MARKS EXIST.
THE NAM SUGGESTS A MIN CORRIDOR OF WEAK INSTABILITY ACROSS MUCH
OF THE AREA SUNDAY WITH CONVECTION AND CLOUDS ALREADY INTO THE
AREA AND BETTER DESTABILIZATION TO OUR WEST AND EAST. THE GFS AND
ECMWF SHOW BETTER DESTABILIZATION THROUGH THE DAY. EVEN IF WE
DESTABILIZE... BETTER WIND FIELDS ARE POSITIONED TO OUR WEST AND
NORTH AND NOT SUPPORTIVE OF SUSTAINED ORGANIZATION. WILL KEEP
POPS HIGH CHANCE GIVEN UNCERTAINTY WITH RESPECT TO COVERAGE.
SHOULD BE WARMER THAN TODAY.
SUNDAY NIGHT THROUGH MONDAY EVENING...WILL CONTINUE WITH HIGH
CHANCE TO LOW END LIKELY POPS FOR CONVECTION...AS THE FRONT VERY
SLOWLY WORKS SOUTH INTO THE AREA BY MONDAY EVENING/NIGHT. BEST
CHANCES WILL EVENTUALLY FOCUS ACROSS THE SOUTHEAST 1/2 TO 2/3 OF
THE AREA.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 208 PM CDT SAT MAY 16 2015
HIGHER THAN AVERAGE CONFIDENCE IN THE EXTENDED.
MODELS AND ENSEMBLES IN FAIR AGREEMENT WITH THE EXTENDED FORECAST.
SURFACE HIGH PRESSURE WILL BE THE MAIN SYNOPTIC SCALE FEATURE IN
CONTROL. HOWEVER THERE WILL BE A WEAK PERTURBATION IN THE NEARLY
ZONAL FLOW ALOFT WITH A REFLECTION OF A SURFACE LOW PASSING JUST TO
OUR SOUTH. THIS WILL BRING AT LEAST A CHANCE OF SHOWERS TO THE AREA
WEDNESDAY. SURFACE BASED CONVECTION LOOKS UNLIKELY WITH POSITIVE
LI`S AND LITTLE TO NO CAPE. ALTHOUGH SHOWALTERS IN VERY POSITIVE...K
INDEX VALUES ARE IN THE MID 20S. SO WILL NOT RULE OUT A CLAP OF
THUNDER BUT NOTHING IMPRESSIVE AT THIS TIME. OTHERWISE HIGH PRESSURE
WILL BE THE DOMINANT FEATURE AFTER THE PASSAGE OF THIS SURFACE LOW.
TEMPERATURES WILL BE AT SLIGHTLY BELOW NORMAL IN THE EXTENDED WITH
WINDS RELATIVELY LIGHT AFTER WEDNESDAY.
&&
.AVIATION...
ISSUED AT 657 PM CDT SAT MAY 16 2015
SCATTERED SHOWERS LIFTING NORTHEAST THROUGH SOUTHEAST MISSOURI AND
NORTHWEST TENNESSEE SHOULD WEAKEN SIGNIFICANTLY BEFORE REACHING
KPAH AND KCGI THIS EVENING. LEFT A VCSH IN FOR THE FIRST HOUR OR
TWO...BUT LITTLE IMPACT IS EXPECTED. OTHERWISE...IT SHOULD BE DRY
THROUGH THE NIGHT.
MVFR CEILINGS NEAR KCGI AND KEVV APPEAR TO BE SCATTERING OUT...SO
WILL ONLY HAVE A CEILING IN FOR THE FIRST HOUR OR TWO. FIGURE ON
RATHER STOUT SOUTH WINDS TO PREVENT FOG FORMATION TONIGHT...BUT
WONT BE SURPRISED IF MVFR CEILINGS RE-DEVELOP LATER ON.
FIGURE ON SCATTERED TS DEVELOPMENT AROUND MIDDAY AND THROUGH THE
AFTERNOON...SO PLAYED IT WITH A PROB30 AT ALL SITES FROM LATE
MORNING THROUGH THE AFTERNOON. A BRIEF MVFR CEILING THROUGH THE
MORNING OUTSIDE OF CONVECTION CANNOT BE RULED OUT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
113 PM EDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1155 AM EDT FRI MAY 15 2015
AREA OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS IN EASTERN PART
OF FORECAST AREA WILL EXIT THE STATE BY 2 PM. HRRR CONTINUES TO
SHOW ISOLATED CONVECTION IN THE AFTERNOON...AND WILL CONTINUE WITH
THIS IN THE CURRENT FORECAST. HAVE UPDATED NDFD BASED ON LATEST
OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 926 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON LATEST RADAR AND
OBSERVATIONAL TRENDS. CURRENTLY A LINE OF SHOWERS WITH A FEW
THUNDERSTORMS IS MOVING ACROSS THE NW PART OF THE FORECAST AREA.
HAVE TIMED THIS ACROSS THE FORECAST AREA BASED ON CURRENT MOVEMENT
AND EXPECTED DIMINISHING TREND. HRRR SEEMS TO BE HANDING THIS
PRETTY GOOD...AND ONCE THIS MOVES OUT EXPECT A LULL BEFORE
ISOLATED CONVECTION BEGINS TO POP UP THIS AFTERNOON.
UPDATE ISSUED AT 715 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
RADAR TRENDS. ISOLATED SHOWERS AND EVEN A STRAY THUNDERSTORM AS
WELL AS SOME SPRINKLES WILL WORK ACROSS THE NORTHERN HALF TO TWO
OF THE AREA AS A SHORTWAVE WORKS THROUGH THE REGION. ADDITIONAL
ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 15 2015
EARLY THIS MORNING...AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS
CENTERED JUST EAST OF THE FLORIDA PENINSULA WITH SHORTWAVE
RIDGING NORTH ALONG THE EASTERN SEABOARD AND ANOTHER SHORTWAVE
RIDGE NORTHWEST INTO PARTS OF THE CENTRAL AND NORTHERN PLAINS. IN
BETWEEN...A SHORTWAVE TROUGH WAS WORKING TOWARD THE GREAT LAKES
AND ACROSS PARTS OF THE OH VALLEY AS IT MOVES AROUND THIS RIDGE.
FURTHER TO THE WEST...A TROUGH WAS MOVING INTO THE WESTERN CONUS.
THE SHORTWAVE WORKING ACROSS THE REGION AND THE ASSOCIATED SFC
SYSTEM WARM FRONT THAT IS GRADUALLY LIFTING NORTH ACROSS THE AREA
HAVE BROUGHT INCREASING MOISTURE THROUGH THE ENTIRE COLUMN TO THE
REGION. THIS HAS MAINLY BEEN REALIZED IN MID AND HIGH CLOUDS SO
FAR AND WARMER TEMPERATURES ATTM COMPARED TO 24 AND 48 HOURS AGO
DUE TO HIGHER SFC DEWPOINTS AND THE CLOUD COVER.
THE SHORTWAVE WILL MOVE INTO THE EASTERN GREAT LAKES AND MOVE
EAST OF THE AREA THIS MORNING...WITH SHORTWAVE RIDGING PROGGED TO
WORK ACROSS THE AREA FROM MIDDAY INTO THE EARLY EVENING. BEHIND
THE WARM FRONT...PW IS PROGGED TO BE IN THE 1.1 TO 1.3 INCH RANGE
OR SO. THE RIDGE AXIS IS EXPECTED TO MOVE EAST OF THE AREA
TONIGHT WITH THE REGION IN SOUTH TO SOUTHWEST FLOW ALOFT THROUGH
THE END OF THE PERIOD. WEAK SHORTWAVES WILL LIKELY MOVE ACROSS THE
AREA IN THIS FLOW AT TIMES FROM THIS EVENING OR TONIGHT THROUGH
THE END OF THE SHORT TERM PERIOD. THE MODEL CONSENSUS IS FOR ONE
OF THESE TO WORK ACROSS THE LOWER OH VALLEY REGION FROM LATE
TONIGHT INTO SATURDAY. WITH THE SOUTH TO SOUTHWEST FLOW CONTINUING
THROUGH THE COLUMN...MOISTURE WILL INCREASE FURTHER AND PW IS
PROGGED TO REACH THE 1.4 TO 1.6 OR 1.7 INCH RANGE ON SATURDAY.
SOME SPRINKLES OR LIGHT SHOWERS WILL REMAIN POSSIBLE THROUGH THE
REMAINDER OF THE OVERNIGHT THROUGH AROUND SUNRISE. ONCE THE
SHORTWAVE MOVES PAST THE AREA TODAY AND THE WARM FRONT LIFTS NORTH
TOWARD THE GREAT LAKES REGION...THERE WILL NOT BE ANY SUBSTANTIAL
TRIGGERS TODAY WITH 500MB HEIGHTS TRENDING UP THROUGH THE DAY.
DIFFERENTIAL HEATING ACROSS THE CUMBERLAND PLATEAU AND THE HIGHER
TERRAIN NEAR THE VA BORDER MAY HELP TO TRIGGER ANY INITIAL
DEVELOPMENT. THE AIRMASS IS EXPECTED TO BE RATHER MOIST AND
SOMEWHAT UNSTABLE BY AFTERNOON WHEN COUPLED WITH DAYTIME HEATING.
THE NAM GUIDANCE IS LIKELY TOO AGGRESSIVE WITH LOW LEVEL MOISTURE
AND CAPE FOR THIS AFTERNOON...BUT THE LESS AGGRESSIVE GFS HAS
CAPE OF AT LEAST 500 TO 1000 J/KG AND LI OF -2 TO -3C OR SO.
ISOLATED TO SCATTERED COVERAGE OF CONVECTION SEEMS PROBABLE...WITH
OUTFLOWS FROM INITIAL CONVECTION POSSIBLY BEING THE TRIGGER FOR
ADDITIONAL CONVECTION IN OTHER LOCATIONS.
A RELATIVE LULL IN COVERAGE OF CONVECTION IS ANTICIPATED FROM MID
TO LATE EVENING IN THE OVERNIGHT HOURS. HOWEVER...ONCE THE RIDGE
AXIS SHIFTS TO THE EAST AND AS A SHORTWAVE APPROACHES FROM THE
SOUTHWEST...ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE LATE
TONIGHT AND CONTINUING INTO SATURDAY. MODELS HAVE CAPE OF ABOUT
1000 TO 1500 J/KG OF SBCAPE ON SATURDAY WITH THIS GENERALLY BEING
OF THE TALL SKINNY CAPE VARIETY. WITH THE SHORTWAVE PASSING
THROUGH THE AREA AND DEWPOINTS EXPECTED TO BE SOLIDLY AT 60F OR
HIGHER...COVERAGE OF CONVECTION SHOULD BE MORE SUBSTANTIAL THAN ON
FRIDAY. THE PW WILL ALSO BE QUITE HIGH FOR MID MAY...AND WARM
CLOUD DEPTHS MAY ALSO APPROACH 10KFT OR MORE. WHAT CONVECTION THAT
DOES DEVELOP ON SATURDAY MAY BE RATHER EFFICIENT RAIN PRODUCERS
WITH QUITE SUBSTANTIAL RAIN RATES. THE STORM MOTIONS ARE PROGGED
TO BE NEARLY 20KTS...SO A LOCATION MAY NEED TO RECEIVE MULTIPLE
STORMS BEFORE HYDRO PROBLEMS MIGHT BEGIN. THE LAST FEW DAYS HAVE
BEEN DRY SO INITIAL STORMS MAY SERVE TO PRIME A LOCATION. ANY
LOCATIONS THAT RECEIVE MULTIPLE STORMS WOULD HAVE THE THREAT FOR
AT LEAST SOME MINOR FLOODING ISSUES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 401 AM EDT FRI MAY 15 2015
WE WILL BEGIN THE LONG TERM PERIOD WITH WARM AND MOIST ENVIRONMENT
AHEAD OF UPPER LEVEL LOW AND FRONT ACROSS THE PLAINS. GENERALLY
WEAK WAVES TRAVELING ALONG THE EDGE OF UPPER LEVEL RIDGE AND
AFTERNOON HEATING WILL HELP TRIGGER SHOWERS AND THUNDERSTORMS
ACROSS THE REGION ESPECIALLY IN THE AFTERNOON ONCE CONVECTIVE
TEMPS ARE REACHED. FORECAST SOUNDINGS AND TIME HEIGHT ANALYSIS
INDICATE MOIST COLUMN WITH PWATS IN THE AROUND 1.7 INCHES OR
HIGHER AT TIMES...SO ANY STORMS THAT FIRE HAVE THE POTENTIAL TO
PRODUCE HEAVY RAINFALL RATES SUNDAY INTO MONDAY. THE UPPER LEVEL
LOW ACROSS THE PLAINS WILL MOVE INTO THE GREAT LAKES AND BEGINS TO
FLATTEN OUT THE RIDGING IN PLACE AS WE MOVE INTO MONDAY. SURFACE
FRONT WILL ALSO APPROACH THE REGION MONDAY AND THIS COUPLED WITH
HEIGHT FALLS WILL BRING LIKELY POPS INTO THE REGION AHEAD OF
SURFACE BOUNDARY. KEEP THUNDER IN THE EVENING MONDAY BEFORE
TAPERING OFF INTO RAIN SHOWERS OVERNIGHT INTO TUESDAY MORNING.
RIGHT NOW IT LOOKS LIKE FRONT WILL COME THOUGH SOMETIME TUESDAY
MORNING OR EARLY AFTERNOON...WITH SLIGHTLY DIFFERING TIMING WITH
LONG RANGE MODELS. EITHER WAY THIS WILL USHER IN DRYER AND COOLER
AIR...AS SURFACE HIGH PRESSURE AND NORTHERLY FLOW BUILD INTO THE
REGION BY MID WEEK. WEDNESDAY WILL FEATURE DRY AND COOLER
CONDITIONS...WITH TEMPS TOPING OUT IN THE LOWER 70S. THIS WILL BE
SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. SLIGHT RETURN OF
MOISTURE BY LATE WEEK...BUT RIGHT NOW KEEP IN MOSTLY DRY THROUGH
THE REMAINDER OF THE LONG TERM PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 113 PM EDT FRI MAY 15 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD...BUT
ISOLATED SHOWERS AND THUNDERSTORMS WILL RESULT IN A FEW SPOTS
BRIEFLY DROPPING TO IFR THIS AFTERNOON. AN AREA OF SHOWERS AND
THUNDERSTORMS OVER FAR EASTERN KY AT 17Z WILL EXIT THE STATE BY
18Z. OTHER ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP AND AFFECT THE FORECAST AREA BETWEEN 18Z AND 22Z. THE AREA
MOST LIKELY TO BE AFFECTED BY THE ISOLATED THUNDERSTORMS WILL BE
THE SOUTHWEST PART OF THE FORECAST AREA. HAVE INCLUDED VCTS FOR
SME AND LOZ TO ACCOUNT FOR THIS. IT SHOULD BE NOTED THAT
CONFIDENCE IN LOCATION AND TIMING OF THUNDERSTORMS THIS AFTERNOON
REMAINS LOW. SOUTHWEST FLOW WILL RESULT IN INCREASING MOISTURE
ACROSS THE AREA INTO SATURDAY...AND AS A RESULT EXPECT COVERAGE OF
SHOWERS AND THUNDERSTORMS TO INCREASE SATURDAY AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JP
LONG TERM...DJ
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1155 AM EDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 1155 AM EDT FRI MAY 15 2015
AREA OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS IN EASTERN PART
OF FORECAST AREA WILL EXIT THE STATE BY 2 PM. HRRR CONTINUES TO
SHOW ISOLATED CONVECTION IN THE AFTERNOON...AND WILL CONTINUE WITH
THIS IN THE CURRENT FORECAST. HAVE UPDATED NDFD BASED ON LATEST
OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 926 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON LATEST RADAR AND
OBSERVATIONAL TRENDS. CURRENTLY A LINE OF SHOWERS WITH A FEW
THUNDERSTORMS IS MOVING ACROSS THE NW PART OF THE FORECAST AREA.
HAVE TIMED THIS ACROSS THE FORECAST AREA BASED ON CURRENT MOVEMENT
AND EXPECTED DIMINISHING TREND. HRRR SEEMS TO BE HANDING THIS
PRETTY GOOD...AND ONCE THIS MOVES OUT EXPECT A LULL BEFORE
ISOLATED CONVECTION BEGINS TO POP UP THIS AFTERNOON.
UPDATE ISSUED AT 715 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
RADAR TRENDS. ISOLATED SHOWERS AND EVEN A STRAY THUNDERSTORM AS
WELL AS SOME SPRINKLES WILL WORK ACROSS THE NORTHERN HALF TO TWO
OF THE AREA AS A SHORTWAVE WORKS THROUGH THE REGION. ADDITIONAL
ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 15 2015
EARLY THIS MORNING...AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS
CENTERED JUST EAST OF THE FLORIDA PENINSULA WITH SHORTWAVE
RIDGING NORTH ALONG THE EASTERN SEABOARD AND ANOTHER SHORTWAVE
RIDGE NORTHWEST INTO PARTS OF THE CENTRAL AND NORTHERN PLAINS. IN
BETWEEN...A SHORTWAVE TROUGH WAS WORKING TOWARD THE GREAT LAKES
AND ACROSS PARTS OF THE OH VALLEY AS IT MOVES AROUND THIS RIDGE.
FURTHER TO THE WEST...A TROUGH WAS MOVING INTO THE WESTERN CONUS.
THE SHORTWAVE WORKING ACROSS THE REGION AND THE ASSOCIATED SFC
SYSTEM WARM FRONT THAT IS GRADUALLY LIFTING NORTH ACROSS THE AREA
HAVE BROUGHT INCREASING MOISTURE THROUGH THE ENTIRE COLUMN TO THE
REGION. THIS HAS MAINLY BEEN REALIZED IN MID AND HIGH CLOUDS SO
FAR AND WARMER TEMPERATURES ATTM COMPARED TO 24 AND 48 HOURS AGO
DUE TO HIGHER SFC DEWPOINTS AND THE CLOUD COVER.
THE SHORTWAVE WILL MOVE INTO THE EASTERN GREAT LAKES AND MOVE
EAST OF THE AREA THIS MORNING...WITH SHORTWAVE RIDGING PROGGED TO
WORK ACROSS THE AREA FROM MIDDAY INTO THE EARLY EVENING. BEHIND
THE WARM FRONT...PW IS PROGGED TO BE IN THE 1.1 TO 1.3 INCH RANGE
OR SO. THE RIDGE AXIS IS EXPECTED TO MOVE EAST OF THE AREA
TONIGHT WITH THE REGION IN SOUTH TO SOUTHWEST FLOW ALOFT THROUGH
THE END OF THE PERIOD. WEAK SHORTWAVES WILL LIKELY MOVE ACROSS THE
AREA IN THIS FLOW AT TIMES FROM THIS EVENING OR TONIGHT THROUGH
THE END OF THE SHORT TERM PERIOD. THE MODEL CONSENSUS IS FOR ONE
OF THESE TO WORK ACROSS THE LOWER OH VALLEY REGION FROM LATE
TONIGHT INTO SATURDAY. WITH THE SOUTH TO SOUTHWEST FLOW CONTINUING
THROUGH THE COLUMN...MOISTURE WILL INCREASE FURTHER AND PW IS
PROGGED TO REACH THE 1.4 TO 1.6 OR 1.7 INCH RANGE ON SATURDAY.
SOME SPRINKLES OR LIGHT SHOWERS WILL REMAIN POSSIBLE THROUGH THE
REMAINDER OF THE OVERNIGHT THROUGH AROUND SUNRISE. ONCE THE
SHORTWAVE MOVES PAST THE AREA TODAY AND THE WARM FRONT LIFTS NORTH
TOWARD THE GREAT LAKES REGION...THERE WILL NOT BE ANY SUBSTANTIAL
TRIGGERS TODAY WITH 500MB HEIGHTS TRENDING UP THROUGH THE DAY.
DIFFERENTIAL HEATING ACROSS THE CUMBERLAND PLATEAU AND THE HIGHER
TERRAIN NEAR THE VA BORDER MAY HELP TO TRIGGER ANY INITIAL
DEVELOPMENT. THE AIRMASS IS EXPECTED TO BE RATHER MOIST AND
SOMEWHAT UNSTABLE BY AFTERNOON WHEN COUPLED WITH DAYTIME HEATING.
THE NAM GUIDANCE IS LIKELY TOO AGGRESSIVE WITH LOW LEVEL MOISTURE
AND CAPE FOR THIS AFTERNOON...BUT THE LESS AGGRESSIVE GFS HAS
CAPE OF AT LEAST 500 TO 1000 J/KG AND LI OF -2 TO -3C OR SO.
ISOLATED TO SCATTERED COVERAGE OF CONVECTION SEEMS PROBABLE...WITH
OUTFLOWS FROM INITIAL CONVECTION POSSIBLY BEING THE TRIGGER FOR
ADDITIONAL CONVECTION IN OTHER LOCATIONS.
A RELATIVE LULL IN COVERAGE OF CONVECTION IS ANTICIPATED FROM MID
TO LATE EVENING IN THE OVERNIGHT HOURS. HOWEVER...ONCE THE RIDGE
AXIS SHIFTS TO THE EAST AND AS A SHORTWAVE APPROACHES FROM THE
SOUTHWEST...ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE LATE
TONIGHT AND CONTINUING INTO SATURDAY. MODELS HAVE CAPE OF ABOUT
1000 TO 1500 J/KG OF SBCAPE ON SATURDAY WITH THIS GENERALLY BEING
OF THE TALL SKINNY CAPE VARIETY. WITH THE SHORTWAVE PASSING
THROUGH THE AREA AND DEWPOINTS EXPECTED TO BE SOLIDLY AT 60F OR
HIGHER...COVERAGE OF CONVECTION SHOULD BE MORE SUBSTANTIAL THAN ON
FRIDAY. THE PW WILL ALSO BE QUITE HIGH FOR MID MAY...AND WARM
CLOUD DEPTHS MAY ALSO APPROACH 10KFT OR MORE. WHAT CONVECTION THAT
DOES DEVELOP ON SATURDAY MAY BE RATHER EFFICIENT RAIN PRODUCERS
WITH QUITE SUBSTANTIAL RAIN RATES. THE STORM MOTIONS ARE PROGGED
TO BE NEARLY 20KTS...SO A LOCATION MAY NEED TO RECEIVE MULTIPLE
STORMS BEFORE HYDRO PROBLEMS MIGHT BEGIN. THE LAST FEW DAYS HAVE
BEEN DRY SO INITIAL STORMS MAY SERVE TO PRIME A LOCATION. ANY
LOCATIONS THAT RECEIVE MULTIPLE STORMS WOULD HAVE THE THREAT FOR
AT LEAST SOME MINOR FLOODING ISSUES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 401 AM EDT FRI MAY 15 2015
WE WILL BEGIN THE LONG TERM PERIOD WITH WARM AND MOIST ENVIRONMENT
AHEAD OF UPPER LEVEL LOW AND FRONT ACROSS THE PLAINS. GENERALLY
WEAK WAVES TRAVELING ALONG THE EDGE OF UPPER LEVEL RIDGE AND
AFTERNOON HEATING WILL HELP TRIGGER SHOWERS AND THUNDERSTORMS
ACROSS THE REGION ESPECIALLY IN THE AFTERNOON ONCE CONVECTIVE
TEMPS ARE REACHED. FORECAST SOUNDINGS AND TIME HEIGHT ANALYSIS
INDICATE MOIST COLUMN WITH PWATS IN THE AROUND 1.7 INCHES OR
HIGHER AT TIMES...SO ANY STORMS THAT FIRE HAVE THE POTENTIAL TO
PRODUCE HEAVY RAINFALL RATES SUNDAY INTO MONDAY. THE UPPER LEVEL
LOW ACROSS THE PLAINS WILL MOVE INTO THE GREAT LAKES AND BEGINS TO
FLATTEN OUT THE RIDGING IN PLACE AS WE MOVE INTO MONDAY. SURFACE
FRONT WILL ALSO APPROACH THE REGION MONDAY AND THIS COUPLED WITH
HEIGHT FALLS WILL BRING LIKELY POPS INTO THE REGION AHEAD OF
SURFACE BOUNDARY. KEEP THUNDER IN THE EVENING MONDAY BEFORE
TAPERING OFF INTO RAIN SHOWERS OVERNIGHT INTO TUESDAY MORNING.
RIGHT NOW IT LOOKS LIKE FRONT WILL COME THOUGH SOMETIME TUESDAY
MORNING OR EARLY AFTERNOON...WITH SLIGHTLY DIFFERING TIMING WITH
LONG RANGE MODELS. EITHER WAY THIS WILL USHER IN DRYER AND COOLER
AIR...AS SURFACE HIGH PRESSURE AND NORTHERLY FLOW BUILD INTO THE
REGION BY MID WEEK. WEDNESDAY WILL FEATURE DRY AND COOLER
CONDITIONS...WITH TEMPS TOPING OUT IN THE LOWER 70S. THIS WILL BE
SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. SLIGHT RETURN OF
MOISTURE BY LATE WEEK...BUT RIGHT NOW KEEP IN MOSTLY DRY THROUGH
THE REMAINDER OF THE LONG TERM PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 720 AM EDT FRI MAY 15 2015
VFR CONDITIONS ARE EXPECTED TO PREVAIL ON AVERAGE THROUGH THE
PERIOD. THE FLOW ALOFT WILL CONTINUE TO BE SWRLY...ALLOWING FOR AN
A CONTINUED INCREASE IN MOISTURE FROM TOP DOWN. A FEW SPRINKLES
AND A STRAY SHRA OR TSRA WILL MOVE ACROSS NORTHERN PARTS OF THE
AREA THROUGH AROUND 15Z AND COULD AFFECT MAINLY SYM. CU SHOULD
DEVELOP FROM 15Z ON...WITH ISOLATED TO SCATTERED SHRA AND TSRA.
CONFIDENCE IN THE EXACT LOCATION AND TIMING OF THIS REMAINS
LOW...BUT WE HAVE OPTED TO JUST USE VCTS FROM 17Z THROUGH 23Z. ANY
DIRECT HIT FROM SHRA OR TSRA COULD BRING A BRIEF PERIOD OF IFR OR
LOWER VIS AND OR CIGS. THERE SHOULD BE A LULL IN CONVECTION
CHANCES BETWEEN 23Z AND 6Z...BUT AS ANOTHER DISTURBANCE
NEARS...ISOLATED TO SCATTERED SHRA AND TSRA WILL BE POSSIBLE AT
THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS JACKSON KY
927 AM EDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 926 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON LATEST RADAR AND
OBSERVATIONAL TRENDS. CURRENTLY A LINE OF SHOWERS WITH A FEW
THUNDERSTORMS IS MOVING ACROSS THE NW PART OF THE FORECAST AREA.
HAVE TIMED THIS ACROSS THE FORECAST AREA BASED ON CURRENT MOVEMENT
AND EXPECTED DIMINISHING TREND. HRRR SEEMS TO BE HANDING THIS
PRETTY GOOD...AND ONCE THIS MOVES OUT EXPECT A LULL BEFORE
ISOLATED CONVECTION BEGINS TO POP UP THIS AFTERNOON.
UPDATE ISSUED AT 715 AM EDT FRI MAY 15 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBSERVATIONS AND
RADAR TRENDS. ISOLATED SHOWERS AND EVEN A STRAY THUNDERSTORM AS
WELL AS SOME SPRINKLES WILL WORK ACROSS THE NORTHERN HALF TO TWO
OF THE AREA AS A SHORTWAVE WORKS THROUGH THE REGION. ADDITIONAL
ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM EDT FRI MAY 15 2015
EARLY THIS MORNING...AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS
CENTERED JUST EAST OF THE FLORIDA PENINSULA WITH SHORTWAVE
RIDGING NORTH ALONG THE EASTERN SEABOARD AND ANOTHER SHORTWAVE
RIDGE NORTHWEST INTO PARTS OF THE CENTRAL AND NORTHERN PLAINS. IN
BETWEEN...A SHORTWAVE TROUGH WAS WORKING TOWARD THE GREAT LAKES
AND ACROSS PARTS OF THE OH VALLEY AS IT MOVES AROUND THIS RIDGE.
FURTHER TO THE WEST...A TROUGH WAS MOVING INTO THE WESTERN CONUS.
THE SHORTWAVE WORKING ACROSS THE REGION AND THE ASSOCIATED SFC
SYSTEM WARM FRONT THAT IS GRADUALLY LIFTING NORTH ACROSS THE AREA
HAVE BROUGHT INCREASING MOISTURE THROUGH THE ENTIRE COLUMN TO THE
REGION. THIS HAS MAINLY BEEN REALIZED IN MID AND HIGH CLOUDS SO
FAR AND WARMER TEMPERATURES ATTM COMPARED TO 24 AND 48 HOURS AGO
DUE TO HIGHER SFC DEWPOINTS AND THE CLOUD COVER.
THE SHORTWAVE WILL MOVE INTO THE EASTERN GREAT LAKES AND MOVE
EAST OF THE AREA THIS MORNING...WITH SHORTWAVE RIDGING PROGGED TO
WORK ACROSS THE AREA FROM MIDDAY INTO THE EARLY EVENING. BEHIND
THE WARM FRONT...PW IS PROGGED TO BE IN THE 1.1 TO 1.3 INCH RANGE
OR SO. THE RIDGE AXIS IS EXPECTED TO MOVE EAST OF THE AREA
TONIGHT WITH THE REGION IN SOUTH TO SOUTHWEST FLOW ALOFT THROUGH
THE END OF THE PERIOD. WEAK SHORTWAVES WILL LIKELY MOVE ACROSS THE
AREA IN THIS FLOW AT TIMES FROM THIS EVENING OR TONIGHT THROUGH
THE END OF THE SHORT TERM PERIOD. THE MODEL CONSENSUS IS FOR ONE
OF THESE TO WORK ACROSS THE LOWER OH VALLEY REGION FROM LATE
TONIGHT INTO SATURDAY. WITH THE SOUTH TO SOUTHWEST FLOW CONTINUING
THROUGH THE COLUMN...MOISTURE WILL INCREASE FURTHER AND PW IS
PROGGED TO REACH THE 1.4 TO 1.6 OR 1.7 INCH RANGE ON SATURDAY.
SOME SPRINKLES OR LIGHT SHOWERS WILL REMAIN POSSIBLE THROUGH THE
REMAINDER OF THE OVERNIGHT THROUGH AROUND SUNRISE. ONCE THE
SHORTWAVE MOVES PAST THE AREA TODAY AND THE WARM FRONT LIFTS NORTH
TOWARD THE GREAT LAKES REGION...THERE WILL NOT BE ANY SUBSTANTIAL
TRIGGERS TODAY WITH 500MB HEIGHTS TRENDING UP THROUGH THE DAY.
DIFFERENTIAL HEATING ACROSS THE CUMBERLAND PLATEAU AND THE HIGHER
TERRAIN NEAR THE VA BORDER MAY HELP TO TRIGGER ANY INITIAL
DEVELOPMENT. THE AIRMASS IS EXPECTED TO BE RATHER MOIST AND
SOMEWHAT UNSTABLE BY AFTERNOON WHEN COUPLED WITH DAYTIME HEATING.
THE NAM GUIDANCE IS LIKELY TOO AGGRESSIVE WITH LOW LEVEL MOISTURE
AND CAPE FOR THIS AFTERNOON...BUT THE LESS AGGRESSIVE GFS HAS
CAPE OF AT LEAST 500 TO 1000 J/KG AND LI OF -2 TO -3C OR SO.
ISOLATED TO SCATTERED COVERAGE OF CONVECTION SEEMS PROBABLE...WITH
OUTFLOWS FROM INITIAL CONVECTION POSSIBLY BEING THE TRIGGER FOR
ADDITIONAL CONVECTION IN OTHER LOCATIONS.
A RELATIVE LULL IN COVERAGE OF CONVECTION IS ANTICIPATED FROM MID
TO LATE EVENING IN THE OVERNIGHT HOURS. HOWEVER...ONCE THE RIDGE
AXIS SHIFTS TO THE EAST AND AS A SHORTWAVE APPROACHES FROM THE
SOUTHWEST...ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE LATE
TONIGHT AND CONTINUING INTO SATURDAY. MODELS HAVE CAPE OF ABOUT
1000 TO 1500 J/KG OF SBCAPE ON SATURDAY WITH THIS GENERALLY BEING
OF THE TALL SKINNY CAPE VARIETY. WITH THE SHORTWAVE PASSING
THROUGH THE AREA AND DEWPOINTS EXPECTED TO BE SOLIDLY AT 60F OR
HIGHER...COVERAGE OF CONVECTION SHOULD BE MORE SUBSTANTIAL THAN ON
FRIDAY. THE PW WILL ALSO BE QUITE HIGH FOR MID MAY...AND WARM
CLOUD DEPTHS MAY ALSO APPROACH 10KFT OR MORE. WHAT CONVECTION THAT
DOES DEVELOP ON SATURDAY MAY BE RATHER EFFICIENT RAIN PRODUCERS
WITH QUITE SUBSTANTIAL RAIN RATES. THE STORM MOTIONS ARE PROGGED
TO BE NEARLY 20KTS...SO A LOCATION MAY NEED TO RECEIVE MULTIPLE
STORMS BEFORE HYDRO PROBLEMS MIGHT BEGIN. THE LAST FEW DAYS HAVE
BEEN DRY SO INITIAL STORMS MAY SERVE TO PRIME A LOCATION. ANY
LOCATIONS THAT RECEIVE MULTIPLE STORMS WOULD HAVE THE THREAT FOR
AT LEAST SOME MINOR FLOODING ISSUES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 401 AM EDT FRI MAY 15 2015
WE WILL BEGIN THE LONG TERM PERIOD WITH WARM AND MOIST ENVIRONMENT
AHEAD OF UPPER LEVEL LOW AND FRONT ACROSS THE PLAINS. GENERALLY
WEAK WAVES TRAVELING ALONG THE EDGE OF UPPER LEVEL RIDGE AND
AFTERNOON HEATING WILL HELP TRIGGER SHOWERS AND THUNDERSTORMS
ACROSS THE REGION ESPECIALLY IN THE AFTERNOON ONCE CONVECTIVE
TEMPS ARE REACHED. FORECAST SOUNDINGS AND TIME HEIGHT ANALYSIS
INDICATE MOIST COLUMN WITH PWATS IN THE AROUND 1.7 INCHES OR
HIGHER AT TIMES...SO ANY STORMS THAT FIRE HAVE THE POTENTIAL TO
PRODUCE HEAVY RAINFALL RATES SUNDAY INTO MONDAY. THE UPPER LEVEL
LOW ACROSS THE PLAINS WILL MOVE INTO THE GREAT LAKES AND BEGINS TO
FLATTEN OUT THE RIDGING IN PLACE AS WE MOVE INTO MONDAY. SURFACE
FRONT WILL ALSO APPROACH THE REGION MONDAY AND THIS COUPLED WITH
HEIGHT FALLS WILL BRING LIKELY POPS INTO THE REGION AHEAD OF
SURFACE BOUNDARY. KEEP THUNDER IN THE EVENING MONDAY BEFORE
TAPERING OFF INTO RAIN SHOWERS OVERNIGHT INTO TUESDAY MORNING.
RIGHT NOW IT LOOKS LIKE FRONT WILL COME THOUGH SOMETIME TUESDAY
MORNING OR EARLY AFTERNOON...WITH SLIGHTLY DIFFERING TIMING WITH
LONG RANGE MODELS. EITHER WAY THIS WILL USHER IN DRYER AND COOLER
AIR...AS SURFACE HIGH PRESSURE AND NORTHERLY FLOW BUILD INTO THE
REGION BY MID WEEK. WEDNESDAY WILL FEATURE DRY AND COOLER
CONDITIONS...WITH TEMPS TOPING OUT IN THE LOWER 70S. THIS WILL BE
SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR. SLIGHT RETURN OF
MOISTURE BY LATE WEEK...BUT RIGHT NOW KEEP IN MOSTLY DRY THROUGH
THE REMAINDER OF THE LONG TERM PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 720 AM EDT FRI MAY 15 2015
VFR CONDITIONS ARE EXPECTED TO PREVAIL ON AVERAGE THROUGH THE
PERIOD. THE FLOW ALOFT WILL CONTINUE TO BE SWRLY...ALLOWING FOR AN
A CONTINUED INCREASE IN MOISTURE FROM TOP DOWN. A FEW SPRINKLES
AND A STRAY SHRA OR TSRA WILL MOVE ACROSS NORTHERN PARTS OF THE
AREA THROUGH AROUND 15Z AND COULD AFFECT MAINLY SYM. CU SHOULD
DEVELOP FROM 15Z ON...WITH ISOLATED TO SCATTERED SHRA AND TSRA.
CONFIDENCE IN THE EXACT LOCATION AND TIMING OF THIS REMAINS
LOW...BUT WE HAVE OPTED TO JUST USE VCTS FROM 17Z THROUGH 23Z. ANY
DIRECT HIT FROM SHRA OR TSRA COULD BRING A BRIEF PERIOD OF IFR OR
LOWER VIS AND OR CIGS. THERE SHOULD BE A LULL IN CONVECTION
CHANCES BETWEEN 23Z AND 6Z...BUT AS ANOTHER DISTURBANCE
NEARS...ISOLATED TO SCATTERED SHRA AND TSRA WILL BE POSSIBLE AT
THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1157 PM CDT THU MAY 14 2015
.UPDATE...
UPDATED AVIATION SECTION FOR 06Z TAF ISSUANCE
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 254 PM CDT THU MAY 14 2015
ALTHOUGH MID-LEVEL REGION OF THE RIDGE WEAKENED FURTHER EAST THAN
ANTICIPATED IN THE WAKE OF THE EJECTING SHORTWAVE TROUGH TO THE
NORTH AND NORTHEAST...SUBSIDENCE SHOULD BUILD BACK IN THIS
EVENING WITH A SMALLER AMPLITUDE RIDGE ALOFT. THIS SUBSIDENCE WILL
BE SHORT LIVED AS THE NEXT SHORT WAVE ROTATING OUT OF THE ROCKIES
MOVES INTO THE WFO PAH FORECAST AREA BY FRIDAY MORNING. ATTEMPTED
TO DEPICT THE MINIMA ON POPS AND WEATHER IN THE GRIDS THIS
EVENING...FOLLOWED BY A SMALL CHANCE OF RAIN CLOSER TO DAYBREAK
AHEAD OF A WEAK LOW/MID LEVEL TROUGH AXIS EMBEDDED IN A MEAN
SOUTHWEST FLOW ALOFT.
FROM FRIDAY THROUGH SATURDAY NIGHT...A TRAIN OF SMALL AND
TRANSIENT SHORTWAVE IMPULSES WILL WORK THROUGH THE WFO PAH
FORECAST AREA. THE VARIABILITY IS GOING TO MAKE IT DIFFICULT TO GO
MUCH BEYOND CHANCE CATEGORY THROUGH FRIDAY NIGHT. THE INFLUENCE
WILL INITIALLY BE DIURNAL...BUT WEAK FORCING WILL DOMINATE
SATURDAY AND SATURDAY NIGHT IN THE WARM CONVEYOR BELT.
HOWEVER...THE POP SIGNAL GETS MORE PERSISTENT SATURDAY AND
SATURDAY NIGHT OVER EXTREME SOUTHERN ILLINOIS...MOST OF WEST
KENTUCKY AND SOUTHEAST MISSOURI...AS THE MEAN ISENTROPIC LIFT
ZONE REMAINS FOCUSED ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST.
CHANNELED VORTICITY ORIENTED PARALLEL TO THE UPPER FLOW WILL
MAINTAIN INTERMITTENT RAIN ACTIVITY THROUGH THE PERIOD.
LEANED CLOSER TOWARD THE HIGHER RESOLUTION NAM-WRF DETERMINISTIC
AND ENSEMBLE GUIDANCE...INCLUDING THE HRRR IN THE 06-18 HOUR TIME
FRAME...WITH MORE EMPHASIS TOWARD THE ECMWF AND CANADIAN GUIDANCE
TOWARD SATURDAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 254 PM CDT THU MAY 14 2015
00Z OPS MODELS AND EC/GFS ENSEMBLE MEAN SOLUTIONS REMAINED IN GOOD
AGREEMENT WITH THE OVERALL UPPER AIR PATTERN. AT THE BEGINNING OF
THE PERIOD...A MID LEVEL TROF WILL EJECT NEGATIVE TILT FROM THE
PLAINS INTO THE UPPER MIDWEST SUNDAY. FRONT STILL OFF TO OUR WEST
BUT WITH MOISTURE AND INSTABILITY PRESENT IN AN UNSETTLED SW FLOW
ALOFT...CONTINUED WITH HIGH CHANCE POPS FOR CONVECTION. CONFIDENCE
REMAINS ABOVE AVERAGE.
FRONT WILL SETTLE SOUTH INTO THE AREA LATE SUNDAY NIGHT INTO MONDAY.
LIKELY POPS SUNDAY NIGHT AND ESPECIALLY ACROSS THE SE 2/3 OF THE
CWFA PER THE LATEST OUTPUT. WILL LINGER POPS MONDAY AS THE FRONT
WILL CONTINUE TO PROGRESS SOUTHEAST ACROSS THE AREA. DIMINISHING
POPS MONDAY EVENING...AND IT SHOULD BE DRY AFTER MIDNIGHT MONDAY
NIGHT.
HIGH PRESSURE SHOULD RESULT IN DRY WEATHER TUESDAY THROUGH TUESDAY
NIGHT. THE OVERALL MID LEVEL FLOW PATTERN FLATTENS OUT ACROSS THE
MID CONUS WITH A TROF OFF THE PACIFIC COAST AND OVER SE CANADA. THE
GFS/ECMWF SOLUTIONS OF THE PAST DAY OR SO SUGGEST MODEST MID LEVEL
SUPPORT AND MOISTURE MAY RESULT IN A FEW SHOWERS WEDNESDAY. THURSDAY
IS MORE UNCLEAR. THE MODELS SHOW DECREASING MOISTURE WITH HIGH
PRESSURE TRYING ONCE AGAIN TO BUILD SOUTHEAST. SO NO POPS FOR NOW
THURSDAY.
THE NEW ECMWF GUIDANCE TRENDED A BIT COOLER FOR MONDAY THROUGH
WEDNESDAY. OTHERWISE A CONSENSUS OF THE GFS/GFS ENSEMBLE MOS AND
PREVIOUS ECMWF NUMBERS WERE STEADY. WILL CONTINUE TO MONITOR THIS
TREND. FOR NOW...JUST SLIGHT ADJUSTMENTS TO OUR EXISTING NUMBERS AND
THE OVERALL MOS CONSENSUS FROM THE PAST 48 HOURS.
&&
.AVIATION...
ISSUED AT 1157 PM CDT THU MAY 14 2015
LOTS OF CLEAR SKY WILL GIVE WAY TO INCREASING HIGH CLOUDS BY
MORNING. SOUTHERLY WINDS WILL BE AROUND 5 KNOTS. SCATTERED DIURNAL
CUMULUS CLOUDS WILL FORM FRIDAY MORNING. THE ATMOSPHERE WILL BECOME
QUITE UNSTABLE BY AFTERNOON...LEADING TO BROKEN CUMULUS CLOUDS AND
SOME THUNDERSTORMS. THE GENERAL TREND SHOULD BE FOR STORMS TO
DEVELOP FROM SOUTHWEST TO NORTHEAST...REACHING KEVV/KOWB LATER IN
THE AFTERNOON. THERE IS ENOUGH OF A PROBABILITY OF STORMS TO
INTRODUCE THE MENTION OF VCTS AT ALL TAF SITES IN THE AFTERNOON.
PRECIP SHOULD DIMINISH IN THE EVENING...BUT WITH PLENTY OF MID LEVEL
CLOUDS REMAINING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...CN
AVIATION...MY
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1003 PM CDT SAT MAY 16 2015
.AVIATION...
TERMINAL FORECAST SITES WILL START OUT WITH PREVAILING VFR...BUT
WITH A STRONG SOUTHERLY FLOW IN THE LOWER LEVELS...MVFR CEILINGS
WILL SPREAD AND DEVELOP OVER THE FOUR STATE REGION MAINLY AFTER
17/06Z TO 17/09Z. IFR CONDITIONS WILL QAICKLY FOLLOW ACROSS THE
REGION AND WILL BE SLOW TO RETURN TO MVFR DURING THE MID TO LATE
MORNING . VFR MAY BE RETURNING NEAR MID DAY. SHOWERS AND
THUNDERWSTORMS WILL BE MOVING INTO THE EAST AND NORTHEAST TEXAS AND
SOUTHWEST ARKANSAS TERMINALS AFTER 17/09Z TO 17/11Z WITH SHOWERS
ACROSS NORTH LOUISIANA AND SOUTH CENTRAL ARKANSAS. THUNDERST0RMS
WILL BE SPREADING AND DEEVELOPING OVER THE LOUISIANA AND SOUTH
CETNRAL ARKANSAS SITES NEAR LATE AFTERNOON INTO THE EARLY EVENING.
WINDS WILL BE SOUTH 7-13 KNOTS THROUGH 17/134Z THEN INCREASE TO 10-
15 KNOTS WITH HIGHER GUSTS ESPECIALLY FOR PARTS OF EAST AND
NORTHEAST TEXAS AND ADJACENT SOUTHWEST ARKANSAS. /06/
&&
.PREV DISCUSSION... /ISSUED 933 PM CDT SAT MAY 16 2015/
DISCUSSION...
SEABREEZE CONVECTION DISSIPATED QUICKLY THIS EVENING AND WITH A
CLEAR SCOPE CURRENTLY...HAVE REDUCED POPS THROUGH MIDNIGHT TO
SLIGHT CHANCE VARIETY. THE BIGGER SHOW IS GOING ON TO OUR WEST
WHERE DISCRETE SEVERE THUNDERSTORMS ARE TRYING TO DEVELOP INTO A
BROKEN LINE OF SEVERE CONVECTION...ESPECIALLY ACROSS CENTRAL
OKLAHOMA. LATEST HRRR OUTPUT DOES NOT BRING THIS CONVECTION INTO
OUR EXTREME NW ZONES UNTIL JUST BEFORE 12Z SO HAVE ADJUSTED THE
EXPECTED EASTWARD PROGRESSION OF THIS ACTIVITY WITH THE GRIDS.
LOCAL HEAVY RAINFALL WORDING WAS SHIFTED FURTHER NORTH AND WEST
FROM THE 06-12Z TIMEFRAME AND ADDED THIS MENTION SLIGHTLY FURTHER
EAST DURING THE 12-18Z SUNDAY TIMEFRAME. DID NOT MAKE ANY
ADJUSTMENTS TO THE FFA WHICH WILL GO INTO EFFECT AT 06Z IN THE
MORNING.
OTHER CHANGES INCLUDED SKY GRIDS AND COSMETIC CHANGES TO
WIND/DEWPOINT AND RH GRIDS. OTHERWISE...NO ADDITIONAL CHANGES WERE
NECESSARY THIS EVENING.
UPDATED PACKAGE ALREADY SENT...13.
PREV DISCUSSION... /ISSUED 317 PM CDT SAT MAY 16 2015/
DISCUSSION...
SCATTERED SEA BREEZE TYPE CONVECTION MARCHING NWD THIS AFTN...AND
BEGINNING TO KICK OFF GUSTS FRONTS WITH 30 TO 40 MPH WINDS. DRY
MID LVLS WILL KEEP COVERAGE SCATTERED...UNTIL OVERNIGHT MCS MOVES
DOWN RED RIVER VALLEY. THIS ACTIVITY SHOULD NOT REACH AREA UNTIL
JUST AFTER MIDNIGHT...BUT ADDED NW CORNER OF CWA IN LATE EVE FOR
LIKELY POPS JUST IN CASE...AND LEAVING SOUTHERN SECTIONS AS SLIGHT
CHANCE THIS EVE...WITH AIRMASS MORE WORKED OVER FROM CONVECTION.
FLASH FLOOD WATCH FOR NW SECTIONS OF AREA BEGINNING AT 1 AM. ADDED
LOCALLY HEAVY RAINFALL WITH MCS FOR THOSE SECTIONS...WITH
SATURATED GROUND...JUST A COUPLE INCHES OF RAIN COULD BE A REAL
ISSUE. DEEP SFC LOW MOVG THRU UPPER MIDWEST WILL DRAG ATTENDANT
FRONT ACROSS SOUTHERN PLAINS SUNDAY NIGHT...SWINGING AN EVEN
STRONGER MCS INTO OUR AREA...WHICH SHOULD SPREAD OUT AND BRING
RAIN TO MOST OF THE REGION MONDAY. WILL LIKELY NEED TO REISSUE
FLASH FLOOD WATCH WHICH WILL EXPIRE SUNDAY AT 1 PM...AS PREVIOUS
MCS WILL DIMINISH...AND SHOULD GET A RAIN BREAK FOR AIRMASS TO
RECOVER. SLIGHTLY COOLER AIR IN ZONAL FLOW ALOFT TUESDAY WILL
AFFECT TEMPS SLIGHTLY...AND BRING LOWER RAIN CHANCES TO AREA..BUT
NOT FOR LONG AS FRONT IS EXPECTED TO MEANDER BACK INTO REGION AND
BECOME QUASI STNRY AGAIN BY MID WEEK.
VII
PREV DISCUSSION... /ISSUED 101 PM CDT SAT MAY 16 2015/
AVIATION...
CIGS HAVE BECOME VFR AS OF MIDDAY OVER ALL THE REGION EXCEPT FOR
SCNTRL AR/NE LA...WITH THESE MVFR CIGS OVER THE E EXPECTED TO
BECOME VFR SHORTLY. HOWEVER...SCT CONVECTION HAS DEVELOPED OVER
DEEP E TX INTO N LA/SW AR EARLY THIS AFTERNOON...WITH THIS TREND
EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON
AFFECTING ALL BUT THE TYR AND POSSIBLY TXK TERMINAL. LOCALLY GUSTY
WINDS...MVFR CIGS/REDUCED VSBYS...AND SVR TURBULENCE WILL BE
POSSIBLE IN/NEAR THE CONVECTION...BEFORE THEY DIMINISH SHORTLY
AFTER SUNSET. SHOULD SEE SOME CONVECTIVE DEBRIS LINGER THIS
EVENING...WITH MVFR CIGS EXPECTED TO REDEVELOP/SPREAD N AFTER 06Z
OVER MUCH OF THE REGION. A MCS IS EXPECTED TO DEVELOP LATE THIS
AFTERNOON OVER WCNTRL OK...AND PROGRESS ESE INTO SE OK/EXTREME NE
TX SHORTLY AFTER 06Z...BUT SHOULD GRADUALLY WEAKEN WITH TIME AS IT
ENCOUNTERS A MORE STABLE AIR MASS. HOWEVER...THIS CONVECTION MAY
AFFECT THE TYR/GGG/TXK TERMINALS BETWEEN 09-12Z SUNDAY...AND
SHV/ELD AROUND/SHORTLY AFTER 12Z. HAVE INSERTED MENTION OF VCTS
FOR THESE TERMINALS...WITH ANY ASSOCIATED MESOSCALE BNDRYS
POSSIBLY SCOURING THE LOWER CIGS...ALLOWING FOR A QUICKER RETURN
OF VFR CIGS. THESE SFC BNDRYS MAY EVENTUALLY FOCUS ADDITIONAL SCT
CONVECTION DURING THE AFTERNOON FARTHER SE ACROSS THE
REGION...WITH MVFR CIGS AHEAD OF THE DECAYING COMPLEX EXPECTED TO
LIFT/BECOME VFR BY LATE MORNING. S WINDS 10-15KTS...WITH GUSTS TO
23KTS OVER E TX/SE OK...WILL DIMINISH SLIGHTLY TO 6-12KTS AFTER
00Z. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 86 72 82 / 20 50 60 70
MLU 70 87 72 83 / 20 40 50 70
DEQ 70 83 69 80 / 80 70 70 60
TXK 72 85 70 82 / 50 60 70 60
ELD 70 86 71 81 / 20 40 60 70
TYR 72 85 72 82 / 50 70 60 60
GGG 73 86 72 82 / 50 60 60 70
LFK 73 88 74 83 / 20 40 50 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR ARZ050-051-059-
060-070.
LA...NONE.
OK...FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR OKZ077.
TX...FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR TXZ096-097-
108>112-124>126-136>138.
&&
$$
06
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
933 PM CDT SAT MAY 16 2015
.DISCUSSION...
SEABREEZE CONVECTION DISSIPATED QUICKLY THIS EVENING AND WITH A
CLEAR SCOPE CURRENTLY...HAVE REDUCED POPS THROUGH MIDNIGHT TO
SLIGHT CHANCE VARIETY. THE BIGGER SHOW IS GOING ON TO OUR WEST
WHERE DISCRETE SEVERE THUNDERSTORMS ARE TRYING TO DEVELOP INTO A
BROKEN LINE OF SEVERE CONVECTION...ESPECIALLY ACROSS CENTRAL
OKLAHOMA. LATEST HRRR OUTPUT DOES NOT BRING THIS CONVECTION INTO
OUR EXTREME NW ZONES UNTIL JUST BEFORE 12Z SO HAVE ADJUSTED THE
EXPECTED EASTWARD PROGRESSION OF THIS ACTIVITY WITH THE GRIDS.
LOCAL HEAVY RAINFALL WORDING WAS SHIFTED FURTHER NORTH AND WEST
FROM THE 06-12Z TIMEFRAME AND ADDED THIS MENTION SLIGHTLY FURTHER
EAST DURING THE 12-18Z SUNDAY TIMEFRAME. DID NOT MAKE ANY
ADJUSTMENTS TO THE FFA WHICH WILL GO INTO EFFECT AT 06Z IN THE
MORNING.
OTHER CHANGES INCLUDED SKY GRIDS AND COSMETIC CHANGES TO
WIND/DEWPOINT AND RH GRIDS. OTHERWISE...NO ADDITIONAL CHANGES WERE
NECESSARY THIS EVENING.
UPDATED PACKAGE ALREADY SENT...13.
&&
.PREV DISCUSSION... /ISSUED 317 PM CDT SAT MAY 16 2015/
DISCUSSION...
SCATTERED SEA BREEZE TYPE CONVECTION MARCHING NWD THIS AFTN...AND
BEGINNING TO KICK OFF GUSTS FRONTS WITH 30 TO 40 MPH WINDS. DRY
MID LVLS WILL KEEP COVERAGE SCATTERED...UNTIL OVERNIGHT MCS MOVES
DOWN RED RIVER VALLEY. THIS ACTIVITY SHOULD NOT REACH AREA UNTIL
JUST AFTER MIDNIGHT...BUT ADDED NW CORNER OF CWA IN LATE EVE FOR
LIKELY POPS JUST IN CASE...AND LEAVING SOUTHERN SECTIONS AS SLIGHT
CHANCE THIS EVE...WITH AIRMASS MORE WORKED OVER FROM CONVECTION.
FLASH FLOOD WATCH FOR NW SECTIONS OF AREA BEGINNING AT 1 AM. ADDED
LOCALLY HEAVY RAINFALL WITH MCS FOR THOSE SECTIONS...WITH
SATURATED GROUND...JUST A COUPLE INCHES OF RAIN COULD BE A REAL
ISSUE. DEEP SFC LOW MOVG THRU UPPER MIDWEST WILL DRAG ATTENDANT
FRONT ACROSS SOUTHERN PLAINS SUNDAY NIGHT...SWINGING AN EVEN
STRONGER MCS INTO OUR AREA...WHICH SHOULD SPREAD OUT AND BRING
RAIN TO MOST OF THE REGION MONDAY. WILL LIKELY NEED TO REISSUE
FLASH FLOOD WATCH WHICH WILL EXPIRE SUNDAY AT 1 PM...AS PREVIOUS
MCS WILL DIMINISH...AND SHOULD GET A RAIN BREAK FOR AIRMASS TO
RECOVER. SLIGHTLY COOLER AIR IN ZONAL FLOW ALOFT TUESDAY WILL
AFFECT TEMPS SLIGHTLY...AND BRING LOWER RAIN CHANCES TO AREA..BUT
NOT FOR LONG AS FRONT IS EXPECTED TO MEANDER BACK INTO REGION AND
BECOME QUASI STNRY AGAIN BY MID WEEK.
VII
PREV DISCUSSION... /ISSUED 101 PM CDT SAT MAY 16 2015/
AVIATION...
CIGS HAVE BECOME VFR AS OF MIDDAY OVER ALL THE REGION EXCEPT FOR
SCNTRL AR/NE LA...WITH THESE MVFR CIGS OVER THE E EXPECTED TO
BECOME VFR SHORTLY. HOWEVER...SCT CONVECTION HAS DEVELOPED OVER
DEEP E TX INTO N LA/SW AR EARLY THIS AFTERNOON...WITH THIS TREND
EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON
AFFECTING ALL BUT THE TYR AND POSSIBLY TXK TERMINAL. LOCALLY GUSTY
WINDS...MVFR CIGS/REDUCED VSBYS...AND SVR TURBULENCE WILL BE
POSSIBLE IN/NEAR THE CONVECTION...BEFORE THEY DIMINISH SHORTLY
AFTER SUNSET. SHOULD SEE SOME CONVECTIVE DEBRIS LINGER THIS
EVENING...WITH MVFR CIGS EXPECTED TO REDEVELOP/SPREAD N AFTER 06Z
OVER MUCH OF THE REGION. A MCS IS EXPECTED TO DEVELOP LATE THIS
AFTERNOON OVER WCNTRL OK...AND PROGRESS ESE INTO SE OK/EXTREME NE
TX SHORTLY AFTER 06Z...BUT SHOULD GRADUALLY WEAKEN WITH TIME AS IT
ENCOUNTERS A MORE STABLE AIR MASS. HOWEVER...THIS CONVECTION MAY
AFFECT THE TYR/GGG/TXK TERMINALS BETWEEN 09-12Z SUNDAY...AND
SHV/ELD AROUND/SHORTLY AFTER 12Z. HAVE INSERTED MENTION OF VCTS
FOR THESE TERMINALS...WITH ANY ASSOCIATED MESOSCALE BNDRYS
POSSIBLY SCOURING THE LOWER CIGS...ALLOWING FOR A QUICKER RETURN
OF VFR CIGS. THESE SFC BNDRYS MAY EVENTUALLY FOCUS ADDITIONAL SCT
CONVECTION DURING THE AFTERNOON FARTHER SE ACROSS THE
REGION...WITH MVFR CIGS AHEAD OF THE DECAYING COMPLEX EXPECTED TO
LIFT/BECOME VFR BY LATE MORNING. S WINDS 10-15KTS...WITH GUSTS TO
23KTS OVER E TX/SE OK...WILL DIMINISH SLIGHTLY TO 6-12KTS AFTER
00Z. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 86 72 82 / 20 50 60 70
MLU 70 87 72 83 / 20 40 50 70
DEQ 70 83 69 80 / 80 70 70 60
TXK 72 85 70 82 / 50 60 70 60
ELD 70 86 71 81 / 20 40 60 70
TYR 72 85 72 82 / 50 70 60 60
GGG 73 86 72 82 / 50 60 60 70
LFK 73 88 74 83 / 20 40 50 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH FROM 1 AM CDT SUNDAY THROUGH SUNDAY AFTERNOON
FOR ARZ050-051-059-060-070.
LA...NONE.
OK...FLASH FLOOD WATCH FROM 1 AM CDT SUNDAY THROUGH SUNDAY AFTERNOON
FOR OKZ077.
TX...FLASH FLOOD WATCH FROM 1 AM CDT SUNDAY THROUGH SUNDAY AFTERNOON
FOR TXZ096-097-108>112-124>126-136>138.
&&
$$
15/VII/13
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
534 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WEAK WARM FRONT APPROACHES FROM THE SOUTHWEST TONIGHT. THE WARM
FRONT WILL STALL OVER SOUTHERN NEW ENGLAND LATE TONIGHT AND
SATURDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT SATURDAY NIGHT
OVER THE GULF OF MAINE AND WILL GRADUALLY DRIFT OFF TO THE
SOUTHEAST ON SUNDAY. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHEAST SUNDAY NIGHT AND MONDAY. LOW PRESSURE CROSSING SOUTHERN
QUEBEC MONDAY NIGHT AND TUESDAY WILL DRIVE A COLD FRONT TOWARD THE
REGION. THE FRONT WILL CROSS THE REGION TUESDAY NIGHT. HIGH
PRESSURE WILL BUILD IN FROM THE WEST WEDNESDAY THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATE...HAVE TO LOOK BACK ACROSS CENTRAL NY STATE TO FIND SHOWERS
REACHING THE GROUND AT THIS HOUR. HAVE DELAYED POP SLIGHTLY THIS
EVENING...AS MODEL FORECASTS KEEP US DRY UNTIL AFTER MIDNIGHT.
LATEST HRRR RUN SUPPORTS GLOBAL MODEL GUIDANCE...INDICATING THAT A
SUBTLE S/WV TROF ROUNDING THE RIDGE WILL FORCE A LOOSELY ORGANIZED
COMPLEX OF SHOWERS THRU THE SWRN ZONES LATE TONIGHT AND EARLY SAT.
PREVIOUS DISCUSSION...VERY DRY CONDITIONS WILL REMAIN IN THE
LOWER PORTIONS OF THE ATMOSPHERE LATE THIS AFTERNOON AND EARLY
THIS EVENING. WEAK WARM AIR ADVECTION WILL CONTINUE IN ASSOCIATION
WITH AN APPROACHING WARM FRONT. THE ATMOSPHERE WILL CONTINUE TO
GRADUALLY MOISTEN OVERNIGHT...EVENTUALLY SUFFICIENTLY TO BRING THE
CHANCE FOR A SHOWER TO THE REGION LATER TONIGHT.
IT WILL BE MILDER THAN LAST NIGHT DESPITE THE LOW DEW POINTS DUE
TO THE CLOUD COVER.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
THE GREATEST THREAT OF A SHOWER WILL MAINLY BE SATURDAY MORNING.
HOWEVER...ANY PRECIPITATION WILL BE LIGHT AND BRIEF.
A VERY LOW CHANCE SHOWER MAY LINTER INTO SATURDAY EVENING. THE 12Z
MESOSCALE MODEL SUITE SHOWS LAST OF THE SHOWERS TO MOVE EAST OF
OUR FORECAST AREA AROUND OR SHORTLY AFTER 06Z. IT WILL BE MILDER
ONCE AGAIN WITH OVERNIGHT LOWS MAINLY BETWEEN 45 AND 55 DEGREES.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SHOWERS WILL BE COMING TO AN END OVER WESTERN MAINE SUNDAY MORNING
AS LOW PRESSURE AND WRAP AROUND MOISTURE MOVE OFFSHORE. HIGH
PRESSURE BUILDS IN FROM THE NORTH AND SHOULD MAKE FOR A NICE REST
OF THE DAY AS WELL AS WELL AS A SUNNY START FOR MONDAY. EVENTUALLY
CLOUDS WILL CREEP BACK IN LATER MONDAY AS ANOTHER FRONTAL SYSTEM
MOVES THROUGH MONDAY NIGHT AND TUESDAY... EXITING THE REGION
WEDNESDAY MORNING. CURRENTLY IT LOOKS LIKE THE BULK OF THE
PRECIPITATION WILL FALL DURING THE DAY TUESDAY. AFTER THIS THE
WEEK LOOKS VERY QUIET WEATHER WISE WITH A MOSTLY DRY FRONTAL
PASSAGE ON FRIDAY. THIS WILL JUST BE A WIND SHIFT FOR MUCH OF THE
REGION BUT IT MAY BRING A SHOWER OR TWO TO THE HIGHER TERRAIN.
TEMPERATURES WILL BE IN THE 70S TO NEAR 80 ON SUNDAY BEFORE
DROPPING BACK INTO THE 60S FOR MOST OF THE WORK WEEK. NEXT FRIDAY
WE WILL WARM BACK UP INTO THE 70S ONCE AGAIN. FROST REALLY ONLY
THREATENS IN THE NORTH WEDNESDAY NIGHT AS COLDER AIR FILTERS IN
BEHIND A FRONTAL PASSAGE.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TODAY THROUGH TONIGHT. MVFR/IFR CEILINGS
DEVELOPING SATURDAY.
LONG TERM...POSSIBLE MVFR WITH ANY REMAINING SHOWERS SUNDAY
MORNING. MVFR OR LOWER CEILINGS POSSIBLE MONDAY NIGHT INTO
TUESDAY IN SHOWERS. FOG LIKELY WEDNESDAY MORNING.
&&
.MARINE...
SHORT TERM...A WARM FRONT WILL BUILD TOWARDS THE COASTAL WATERS.
HOWEVER WINDS AND SEAS WILL REMAIN BELOW SCA THRESHOLDS.
LONG TERM...A COLD FRONT CROSSES THE WATERS TUESDAY NIGHT/
WEDNESDAY MORNING. WINDS SHOULD STAY BELOW ADVISORY LEVELS
THROUGH THE PERIOD AS WELL AS WAVES.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY WILL REMAIN IN THE 20S AND 30S THIS EVENING
BEFORE RECOVERING OVERNIGHT UNDER LIGHT WINDS. SHOWERS AND AN
INCREASING ONSHORE FLOW LATE TONIGHT AND SATURDAY WILL HELP TO
MOISTEN FUELS AND EASE FIRE DANGER.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
359 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST
THROUGH THE WEEKEND...BRINGING AN INCREASINGLY WARM AND MOIST
SOUTHERLY FLOW THROUGH THE WEEKEND. A COLD FRONT CROSSES THE REGION
TUESDAY...WITH SEASONABLE TEMPERATURES RETURNING THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
CURRENT SFC ANALYSIS PLACES HIGH PRESSURE JUST OFF THE MID ATLANTIC
COAST WITH A WARM FRONT LIFTING NORTH OF THE REGION. THIS HAS
ALLOWED FOR WARMER/MORE HUMID CONDITIONS TODAY COMPARED TO 24 HOURS
AGO. EARLIER SHORTWAVE HAS PUSHED OFFSHORE THIS AFTERNOON AS
UPSTREAM RIDGING BEGINS TO BUILD INTO THE ERN CONUS. LATEST REGIONAL
RADAR MOSAIC DEPICTS SCT SHOWERS/THUNDERSTORMS OVER THE CNTRL
APPALACHIANS...BUT THE LOCAL AREA REMAINS MOSTLY SUNNY-PARTLY
CLOUDY. CU FIELD OBSERVED ON VISIBLE SATELLITE OVER THE
PIEDMONT...BUT RAP MESOANALYSIS DEPICTS VERY LITTLE INSTABILITY AND
LIFT TO GO ALONG WITH A RATHER DRY AIRMASS. LATEST HRRR PUSHES THE
SHOWERS/THUNDERSTORMS OVER THE CNTRL APPALACHIANS EWD TOWARD THE
PIEDMONT...BUT QUICKLY DISSIPATING AS THEY MOVE OFF THE HIGHER
TERRAIN. THEREFORE...WILL MAINTAIN A DRY FORECAST THIS EVENING.
HIGH PRESSURE PUSHES FARTHER OFFSHORE TONIGHT WITH LIGHT RETURN FLOW
CONTINUING OVERNIGHT. SKIES AVG MOSTLY CLEAR-PARTLY CLOUDY. LOWS IN
THE UPPER 50S-LOW 60S. HAVE KEPT POPS SILENT TONIGHT...BUT WILL NEED
TO MONITOR UPSTREAM CONVECTION AS MODELS ATTEMPT TO SPREAD SHOWERS
SWD TOWARD THE MD ERN SHORE LATE TONIGHT. DRY/STABLE AIRMASS WILL
LIKELY PREVENT SHOWERS FROM MOVING INTO THE REGION.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
UPPER LEVEL RIDGE REMAINS ENTRENCHED OVER THE ERN CONUS THRU THE
SHORT TERM AS SFC HIGH PRESSURE LOCATES OFF THE SOUTHEAST COAST.
RETURN FLOW ON THE WRN PERIPHERY OF THE HIGH WILL RESULT IN A
STEADY/GRADUAL WARMING AND MOISTENING TREND THROUGH THE WEEKEND.
THETA-E ADVECTION AND TEMPS IN THE UPPER 80S WILL PRODUCE A
MARGINALLY UNSTABLE AIRMASS TO GO ALONG WITH INCREASING PWATS AND
STEEPENING LOW-LEVEL LAPSE RATES. BEST MOISTURE AND INSTABILITY
(MLCAPE VALUES 500-1000 J/KG) WILL BE ACROSS THE NW COUNTIES...SO
WILL MAINTAIN SLIGHT CHANCE-CHANCE POPS IN THAT REGION.
OTHERWISE...LACK OF APPRECIABLE FORCING AND MEAGER SHEAR TO GO ALONG
WITH WEAK FLOW SHOULD KEEP THE REMAINDER OF THE AREA DRY.
SHOWERS/THUNDERSTORMS DISSIPATE SAT EVENING WITH THE LOSS OF DAYTIME
HEATING/INSTABILITY. HIGHS SAT WARM INTO THE LOW-MID 80S INLAND AND
UPPER 70S TO LOW 80S ALONG THE COAST.
SHORTWAVE DIGS OFF THE NE COAST SAT NIGHT...PUSHING A BACKDOOR FRONT
SWD TOWARD THE LOCAL AREA. PERTURBATIONS (PERHAPS CONVECTIVELY
INDUCED) WILL ROUND THE RIDGE AND DROP TOWARD THE ERN SHORE. WILL
RETAIN SLIGHT CHANCE-CHANCE POPS NE COUNTIES SAT NIGHT. MILD LOWS
SAT NIGHT IN THE LOW-MID 60S.
EXPECT BETTER AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS SUN AND
MON AS A CLOSED UPPER LEVEL TROUGH FILLS AS IT EJECTS NE FROM THE
CENTRAL ROCKIES INTO THE NORTHERN PLAINS. THIS WILL DAMPEN THE UPPER
LEVEL RIDGE ACROSS THE REGION. ASSOCIATED COLD FRONT WILL REACH THE
OH VALLEY MON. PRESSURE FALLS ON THE LEE SIDE OF THE APPALACHIANS
WILL RESULT IN A SHARPENING LEE/THERMAL TROUGH OVER THE PIEDMONT
INTO CNTRL VA. THE TROUGH WILL PROVIDE BETTER LOW LEVEL CONVERGENCE
AND MODEST FORCING FOR ASCENT. BETTER UVM EXPECTED AS WEAK
PERTURBATIONS ROUND THE RIDGE. THE BACKDOOR FRONT WILL REMAIN JUST
NORTH OF THE LOCAL AREA SUN AFTERNOON...DROPPING OVER THE NE
COUNTIES SUN NIGHT. SHEAR REMAINS MARGINAL...BUT WARMER DEWPOINTS
AND BETTER INSTABILITY EXPECTED. HAVE MAINTAINED CHANCE-SOLID CHANCE
POPS ACROSS THE NRN HALF OF THE LOCAL AREA AND SLIGHT CHANCE-LOW END
CHANCE POPS SRN HALF SUN. HIGHS MID-UPPER 80S...WITH MID-UPPER 70S
ALONG THE COAST SUN. MILD SUN NIGHT (APPROACHING RECORD HI MINS)
WITH LOWS IN THE MID-UPPER 60S. WILL RETAIN SLIGHT CHANCE-CHANCE
POPS MON NIGHT AS THE FRONT DROPS INTO THE REGION. EVEN BETTER
FORCING/MOISTURE/INSTABILITY EXPECTED MON...RESULTING IN BETTER
CHANCES FOR AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS.
WARM AGAIN MON WITH HIGHS IN THE MID-UPPER 80S INLAND AND UPPER
70S/LOW 80S NEAR THE COAST. WITH MARGINAL SHEAR UNDER THE INFLUENCE
OF THE UPPER RIDGE...WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
HOWEVER...A FEW STRONG STORMS MAY PRODUCE GUSTY WINDS AND SMALL HAIL
SUN AND MON. IN ADDITION...PWATS AROUND +2 STD DEV AND VERY LIGHT
STEERING FLOW WILL PRODUCE LOCALLY HEAVY RAINFALL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE EXTENDED BEGINS WITH A WEAK AREA OF HIGH PRES CENTERED OVER
THE MID ATLANTIC KEEPING CONDITIONS UNSETTLED AND A GOOD CHANCE
FOR SHOWERS AND THUNDERSTORMS ESPECIALLY WITH AFTERNOON HEATING.
THE UPPER RIDGE AXIS BREAKS DOWN AND PUSHES EAST MONDAY SUCH THAT BY
TUESDAY THERE WILL BE A WEAK SHORTWAVE MOVING ACROSS THE REGION IN
THE WEST TO NORTHWEST UPPER FLOW. EXPECT ABOUT 30 KT OF SHEAR AND
DECENT INSTABILITY FROM HEATING AND UVM WITH THE UPPER SHORTWAVE.
MLCAPE LOOKS TO BE AROUND 1500 J/KG. THIS SHOULD BE ENOUGH TO GET
STORMS GOING WITH SOME ORGANIZATION. A COLD FRONT PUSHING THROUGH
LATE AFTERNOON / EVENING WILL ALSO HELP TO ORGANIZE STORMS. FOR
NOW HAVE GONE WITH A HIGH CHANCE FOR SHOWERS AND STORMS TUESDAY
BUT LATER FORECASTS WILL LIKELY RAISE POPS EVEN MORE.
THE COLD FRONT REACHES THE COAST TUESDAY EVENING. FOLLOWING THE
FRONT A SURGE OF COOLER AIR IS EXPECTED OVERNIGHT TUESDAY NIGHT INTO
EARLY WEDNESDAY AS HIGH PRES BUILDS IN FROM THE NW. EXPECT ONLY
SLIGHT CHANCE POPS OVERNIGHT TUESDAY AND NO POPS BY WED MORNING.
SLIGHTLY ABOVE NORMAL TEMPS MON AND TUE (LOW TO MID 80S INLAND
MID-UPPER 70S NEAR THE COAST) RETURN TO NEAR NORMAL WEDS- THU
(MID-UPPER 70S INLAND AND LOW 70S NEAR THE COAST. MILD LOWS MON
NIGHT (MID-UPPER 60S) COOL OFF INTO THE LOW-MID 50S INLAND TO
AROUND 60 NEAR THE COAST WEDS NIGHT-THU NIGHT.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SFC HIGH PRESSURE CENTERED JUST OFF THE COAST WITH LOW PRESSURE
MOVING THROUGH THE GREAT LAKES TONIGHT INTO SAT. HAVE MAINTAINED
VFR CONDITIONS THROUGH THE 18Z TAF PERIOD. ONSHORE NE FLOW AT KORF
ALTHOUGH AS SPEEDS INCREASE ALL AREAS TO ~10 KT WINDS SHOULD
BECOME SE OR S ALL AREAS AFTER 20Z. WINDS SHIFT TO THE S/SW
OVERNIGHT...WITH A CONTINUATION OF MAINLY MID/HIGH CLOUDS FROM
15-25 K FT. SOME OF THE GUIDANCE TRIES TO BRING LOW CIGS INTO THE
AREA AROUND 12Z SAT MORNING...THIS SEEMS UNLIKELY GIVEN A SW FLOW
AND ONLY A SHALLOW LAYER OF LOW LEVEL MOISTURE SO HAVE NOT
INCLUDED IN TAFS.
HIGH BECOMES NEARLY STATIONARY OFF THE MID ATLC CST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK...GENLY VFR CONDITIONS WILL PREVAIL.
WARMER AIRMASS/INCREASING MOISTURE COULD ALLOW FOR ISOLATED/WIDELY
SCATTERED TSTMS MAINLY IN THE LATE AFTN AND EVENING HRS (ESP
NORTH)...WITH A BIT MORE COVERAGE OF CONVECTION AT ALL SITES BY
MON/TUE.
&&
.MARINE...
RELATIVELY QUIET MARINE WX CONDS ON TAP FOR THE NEXT COUPLE DAYS.
THE SURFACE HIGH PRES HAS MOVED OFFSHORE THIS AFTN AND REMAINS
CENTERED WELL OFF THE MID ATLC/SE COAST. THIS HAS ALLOWED WINDS TO
BECOME SOUTHEAST THIS AFTERNOON AT 10 TO 15 KT. THE PRES GRADIENT
ALONG THE COAST AND BAY WILL TIGHTEN SLIGHTLY OVERNIGHT AS LOW
PRESSURE TRACKS WELL TO THE NORTH AND THE HIGH REMAINS OFFSHORE.
HAVE BUMPED UP WINDS TO 15 KT OVERNIGHT AND EARLY SATURDAY. SOME
GUSTS TO 18NKT WILL BE POSSIBLE EITHER SIDE OF DAYBREAK. THIS
WILL PUSH WAVES TO 2 FT ACROSS THE BAY AND WITH 2 TO 3 FT IN THE COASTAL
WATERS. WINDS BECOME MORE S TO SW SATURDAY AROUND 10 TO 15 KT BUT
GRADUALLY DECREASE TO 10 KT THROUGH THE AFTERNOON AS THE PRES
GRAD RELAXES. SUNDAY SLY WINDS CONTINUE AROUND 10 KT THEN BECOME
VARIABLE ON MONDAY AS WEAK LOW PRESSURE SETTLES IN OVER THE MID
ATLANTIC. THIS WILL ALSO RESULT INCREASING RAIN CHANCES MONDAY
WITH STORMS POSSIBLE TUESDAY AS A COLD FRONT PUSHES THROUGH. WIND
BECOME NW AROUND 15 KT WITH THE FRONTAL PASSAGE TUESDAY. SCA CONDS
ARE FORECAST TUE NIGHT INTO WEDNESDAY AS A SURGE OF COLD AIR
PUSHING IN BEHIND THE FRONT PUSHED NW WINDS TO 20 KT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/SAM
NEAR TERM...SAM
SHORT TERM...AJZ/SAM
LONG TERM...JAO
AVIATION...LKB
MARINE...MAS/JAO
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
355 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST
THROUGH THE WEEKEND...BRINGING AN INCREASINGLY WARM AND MOIST
SOUTHERLY FLOW THROUGH THE WEEKEND. A COLD FRONT CROSSES THE REGION
TUESDAY...WITH SEASONABLE TEMPERATURES RETURNING THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CURRENT SFC ANALYSIS PLACES HIGH PRESSURE JUST OFF THE MID ATLANTIC
COAST WITH A WARM FRONT LIFTING NORTH OF THE REGION. THIS HAS
ALLOWED FOR WARMER/MORE HUMID CONDITIONS TODAY COMPARED TO 24 HOURS
AGO. EARLIER SHORTWAVE HAS PUSHED OFFSHORE THIS AFTERNOON AS
UPSTREAM RIDGING BEGINS TO BUILD INTO THE ERN CONUS. LATEST REGIONAL
RADAR MOSAIC DEPICTS SCT SHOWERS/THUNDERSTORMS OVER THE CNTRL
APPALACHIANS...BUT THE LOCAL AREA REMAINS MOSTLY SUNNY-PARTLY
CLOUDY. CU FIELD OBSERVED ON VISIBLE SATELLITE OVER THE
PIEDMONT...BUT RAP MESOANALYSIS DEPICTS VERY LITTLE INSTABILITY AND
LIFT TO GO ALONG WITH A RATHER DRY AIRMASS. LATEST HRRR PUSHES THE
SHOWERS/THUNDERSTORMS OVER THE CNTRL APPALACHIANS EWD TOWARD THE
PIEDMONT...BUT QUICKLY DISSIPATING AS THEY MOVE OFF THE HIGHER
TERRAIN. THEREFORE...WILL MAINTAIN A DRY FORECAST THIS EVENING.
HIGH PRESSURE PUSHES FARTHER OFFSHORE TONIGHT WITH LIGHT RETURN FLOW
CONTINUING OVERNIGHT. SKIES AVG MOSTLY CLEAR-PARTLY CLOUDY. LOWS IN
THE UPPER 50S-LOW 60S. HAVE KEPT POPS SILENT TONIGHT...BUT WILL NEED
TO MONITOR UPSTREAM CONVECTION AS MODELS ATTEMPT TO SPREAD SHOWERS
SWD TOWARD THE MD ERN SHORE LATE TONIGHT. DRY/STABLE AIRMASS WILL
LIKELY PREVENT SHOWERS FROM MOVING INTO THE REGION.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
UPPER LEVEL RIDGE REMAINS ENTRENCHED OVER THE ERN CONUS THRU THE
SHORT TERM AS SFC HIGH PRESSURE LOCATES OFF THE SOUTHEAST COAST.
RETURN FLOW ON THE WRN PERIPHERY OF THE HIGH WILL RESULT IN A
STEADY/GRADUAL WARMING AND MOISTENING TREND THROUGH THE WEEKEND.
THETA-E ADVECTION AND TEMPS IN THE UPPER 80S WILL PRODUCE A
MARGINALLY UNSTABLE AIRMASS TO GO ALONG WITH INCREASING PWATS AND
STEEPENING LOW-LEVEL LAPSE RATES. BEST MOISTURE AND INSTABILITY
(MLCAPE VALUES 500-1000 J/KG) WILL BE ACROSS THE NW COUNTIES...SO
WILL MAINTAIN SLIGHT CHANCE-CHANCE POPS IN THAT REGION.
OTHERWISE...LACK OF APPRECIABLE FORCING AND MEAGER SHEAR TO GO ALONG
WITH WEAK FLOW SHOULD KEEP THE REMAINDER OF THE AREA DRY.
SHOWERS/THUNDERSTORMS DISSIPATE SAT EVENING WITH THE LOSS OF DAYTIME
HEATING/INSTABILITY. HIGHS SAT WARM INTO THE LOW-MID 80S INLAND AND
UPPER 70S TO LOW 80S ALONG THE COAST.
SHORTWAVE DIGS OFF THE NE COAST SAT NIGHT...PUSHING A BACKDOOR FRONT
SWD TOWARD THE LOCAL AREA. PERTURBATIONS (PERHAPS CONVECTIVELY
INDUCED) WILL ROUND THE RIDGE AND DROP TOWARD THE ERN SHORE. WILL
RETAIN SLIGHT CHANCE-CHANCE POPS NE COUNTIES SAT NIGHT. MILD LOWS
SAT NIGHT IN THE LOW-MID 60S.
EXPECT BETTER AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS SUN AND
MON AS A CLOSED UPPER LEVEL TROUGH FILLS AS IT EJECTS NE FROM THE
CENTRAL ROCKIES INTO THE NORTHERN PLAINS. THIS WILL DAMPEN THE UPPER
LEVEL RIDGE ACROSS THE REGION. ASSOCIATED COLD FRONT WILL REACH THE
OH VALLEY MON. PRESSURE FALLS ON THE LEE SIDE OF THE APPALACHIANS
WILL RESULT IN A SHARPENING LEE/THERMAL TROUGH OVER THE PIEDMONT
INTO CNTRL VA. THE TROUGH WILL PROVIDE BETTER LOW LEVEL CONVERGENCE
AND MODEST FORCING FOR ASCENT. BETTER UVM EXPECTED AS WEAK
PERTURBATIONS ROUND THE RIDGE. THE BACKDOOR FRONT WILL REMAIN JUST
NORTH OF THE LOCAL AREA SUN AFTERNOON...DROPPING OVER THE NE
COUNTIES SUN NIGHT. SHEAR REMAINS MARGINAL...BUT WARMER DEWPOINTS
AND BETTER INSTABILITY EXPECTED. HAVE MAINTAINED CHANCE-SOLID CHANCE
POPS ACROSS THE NRN HALF OF THE LOCAL AREA AND SLIGHT CHANCE-LOW END
CHANCE POPS SRN HALF SUN. HIGHS MID-UPPER 80S...WITH MID-UPPER 70S
ALONG THE COAST SUN. MILD SUN NIGHT (APPROACHING RECORD HI MINS)
WITH LOWS IN THE MID-UPPER 60S. WILL RETAIN SLIGHT CHANCE-CHANCE
POPS MON NIGHT AS THE FRONT DROPS INTO THE REGION. EVEN BETTER
FORCING/MOISTURE/INSTABILITY EXPECTED MON...RESULTING IN BETTER
CHANCES FOR AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS.
WARM AGAIN MON WITH HIGHS IN THE MID-UPPER 80S INLAND AND UPPER
70S/LOW 80S NEAR THE COAST. WITH MARGINAL SHEAR UNDER THE INFLUENCE
OF THE UPPER RIDGE...WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
HOWEVER...A FEW STRONG STORMS MAY PRODUCE GUSTY WINDS AND SMALL HAIL
SUN AND MON. IN ADDITION...PWATS AROUND +2 STD DEV AND VERY LIGHT
STEERING FLOW WILL PRODUCE LOCALLY HEAVY RAINFALL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
VERY LITTLE CHANGE IS EXPECTED WITH RESPECT TO THE LONGWAVE
PATTERN TONIGHT THROUGH SUNDAY. RETURN FLOW ON THE WRN PERIPHERY
OF THE HIGH WILL RESULT IN A STEADY/GRADUAL WARMING AND MOISTENING
TREND THROUGH THE WEEKEND. PW VALUES RISE AND MID-LEVEL LAPSE
RATES STEEPEN ENOUGH TO ALLOW FOR A SLIGHT CHC/LOW CHC OF
-SHRA/TSRA SATURDAY AFTERNOON/EVENING FOR FAR NW TIER OF PIEDMONT
COUNTIES. OTHERWISE...LITTLE FORCING AND MEAGER SHEAR UNDERNEATH
THE UPPER RIDGE SHOULD KEEP THE REMAINDER OF THE AREA DRY AND
PARTLY TO MOSTLY SUNNY FOR SATURDAY. ANY -SHRA/TSRA SHOULD
DISSIPATE QUICKLY SATURDAY EVENING. HIGHS SATURDAY WARM INTO THE
LOW/MID 80S INLAND WITH UPPER 70S LOW 80S ALONG THE IMMEDIATE
COAST. LOWS TONIGHT SHOULD BE IN THE UPPER 50S/LOW 60S...WITH
LOW/MID 60S SATURDAY NIGHT.
EXPECT A BIT MORE AREAL COVERAGE OF SHRA/TSRA BY SUNDAY AFTERNOON
AND EVENING. A CLOSED UPPER LEVEL TROUGH WILL FILL AS IT EJECTS NE
FROM THE CENTRAL ROCKIES INTO THE NORTHERN PLAINS SUNDAY INTO
SUNDAY NIGHT...WHICH WILL DAMPEN THE UPPER RIDGE ACROSS THE
CENTRAL APPALACHIANS AND NRN MID ATLANTIC. A WEAK LEE TROUGH WILL
DEVELOP DOWNSTREAM ACROSS THE BLUE RIDGE BY LATER
SUNDAY...PROVIDING SOME OW-LEVEL CONVERGENCE AND MODEST FORCING
FOR ASCENT. HIGHEST POPS REMAIN ORIENTED ACROSS THE NORTHWESTERN
THIRD OF THE AREA...ROUGHLY NW OF A LINE FROM FVX-RIC-WAL. MLCAPE
IS MARGINALLY UNSTABLE ACROSS THE NORTH (~1000 J/KG)...BUT SHEAR
REMAINS MINIMAL SO SEVERE STORMS ARE NOT ANTICIPATED. THOUGH WITH
PW RAMPING AOA 1.5" AND WITH VERY LIGHT STEERING FLOW...LOCALLY
HEAVY RAINFALL WOULD APPEAR TO BE THE PRIMARY HAZARD WITH ANY
STORMS. WARMER AND MODERATELY HUMID SUNDAY WITH HIGHS IN THE MID
TO UPPER 80S INLAND...WITH UPPER 70S TO MID 80S ALONG THE
IMMEDIATE COAST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE EXTENDED BEGINS WITH A WEAK AREA OF HIGH PRES CENTERED OVER
THE MID ATLANTIC KEEPING CONDITIONS UNSETTLED AND A GOOD CHANCE
FOR SHOWERS AND THUNDERSTORMS ESPECIALLY WITH AFTERNOON HEATING.
THE UPPER RIDGE AXIS BREAKS DOWN AND PUSHES EAST MONDAY SUCH THAT BY
TUESDAY THERE WILL BE A WEAK SHORTWAVE MOVING ACROSS THE REGION IN
THE WEST TO NORTHWEST UPPER FLOW. EXPECT ABOUT 30 KT OF SHEAR AND
DECENT INSTABILITY FROM HEATING AND UVM WITH THE UPPER SHORTWAVE.
MLCAPE LOOKS TO BE AROUND 1500 J/KG. THIS SHOULD BE ENOUGH TO GET
STORMS GOING WITH SOME ORGANIZATION. A COLD FRONT PUSHING THROUGH
LATE AFTERNOON / EVENING WILL ALSO HELP TO ORGANIZE STORMS. FOR
NOW HAVE GONE WITH A HIGH CHANCE FOR SHOWERS AND STORMS TUESDAY
BUT LATER FORECASTS WILL LIKELY RAISE POPS EVEN MORE.
THE COLD FRONT REACHES THE COAST TUESDAY EVENING. FOLLOWING THE
FRONT A SURGE OF COOLER AIR IS EXPECTED OVERNIGHT TUESDAY NIGHT INTO
EARLY WEDNESDAY AS HIGH PRES BUILDS IN FROM THE NW. EXPECT ONLY
SLIGHT CHANCE POPS OVERNIGHT TUESDAY AND NO POPS BY WED MORNING.
SLIGHTLY ABOVE NORMAL TEMPS MON AND TUE (LOW TO MID 80S INLAND
MID-UPPER 70S NEAR THE COAST) RETURN TO NEAR NORMAL WEDS- THU
(MID-UPPER 70S INLAND AND LOW 70S NEAR THE COAST. MILD LOWS MON
NIGHT (MID-UPPER 60S) COOL OFF INTO THE LOW-MID 50S INLAND TO
AROUND 60 NEAR THE COAST WEDS NIGHT-THU NIGHT.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
SFC HIGH PRESSURE CENTERED JUST OFF THE COAST WITH LOW PRESSURE
MOVING THROUGH THE GREAT LAKES TONIGHT INTO SAT. HAVE MAINTAINED
VFR CONDITIONS THROUGH THE 18Z TAF PERIOD. ONSHORE NE FLOW AT KORF
ALTHOUGH AS SPEEDS INCREASE ALL AREAS TO ~10 KT WINDS SHOULD
BECOME SE OR S ALL AREAS AFTER 20Z. WINDS SHIFT TO THE S/SW
OVERNIGHT...WITH A CONTINUATION OF MAINLY MID/HIGH CLOUDS FROM
15-25 K FT. SOME OF THE GUIDANCE TRIES TO BRING LOW CIGS INTO THE
AREA AROUND 12Z SAT MORNING...THIS SEEMS UNLIKELY GIVEN A SW FLOW
AND ONLY A SHALLOW LAYER OF LOW LEVEL MOISTURE SO HAVE NOT
INCLUDED IN TAFS.
HIGH BECOMES NEARLY STATIONARY OFF THE MID ATLC CST THROUGH THE
WEEKEND INTO EARLY NEXT WEEK...GENLY VFR CONDITIONS WILL PREVAIL.
WARMER AIRMASS/INCREASING MOISTURE COULD ALLOW FOR ISOLATED/WIDELY
SCATTERED TSTMS MAINLY IN THE LATE AFTN AND EVENING HRS (ESP
NORTH)...WITH A BIT MORE COVERAGE OF CONVECTION AT ALL SITES BY
MON/TUE.
&&
.MARINE...
RELATIVELY QUIET MARINE WX CONDS ON TAP FOR THE NEXT COUPLE DAYS.
THE SURFACE HIGH PRES HAS MOVED OFFSHORE THIS AFTN AND REMAINS
CENTERED WELL OFF THE MID ATLC/SE COAST. THIS HAS ALLOWED WINDS TO
BECOME SOUTHEAST THIS AFTERNOON AT 10 TO 15 KT. THE PRES GRADIENT
ALONG THE COAST AND BAY WILL TIGHTEN SLIGHTLY OVERNIGHT AS LOW
PRESSURE TRACKS WELL TO THE NORTH AND THE HIGH REMAINS OFFSHORE.
HAVE BUMPED UP WINDS TO 15 KT OVERNIGHT AND EARLY SATURDAY. SOME
GUSTS TO 18NKT WILL BE POSSIBLE EITHER SIDE OF DAYBREAK. THIS
WILL PUSH WAVES TO 2 FT ACROSS THE BAY AND WITH 2 TO 3 FT IN THE COASTAL
WATERS. WINDS BECOME MORE S TO SW SATURDAY AROUND 10 TO 15 KT BUT
GRADUALLY DECREASE TO 10 KT THROUGH THE AFTERNOON AS THE PRES
GRAD RELAXES. SUNDAY SLY WINDS CONTINUE AROUND 10 KT THEN BECOME
VARIABLE ON MONDAY AS WEAK LOW PRESSURE SETTLES IN OVER THE MID
ATLANTIC. THIS WILL ALSO RESULT INCREASING RAIN CHANCES MONDAY
WITH STORMS POSSIBLE TUESDAY AS A COLD FRONT PUSHES THROUGH. WIND
BECOME NW AROUND 15 KT WITH THE FRONTAL PASSAGE TUESDAY. SCA CONDS
ARE FORECAST TUE NIGHT INTO WEDNESDAY AS A SURGE OF COLD AIR
PUSHING IN BEHIND THE FRONT PUSHED NW WINDS TO 20 KT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/MAM
NEAR TERM...AJZ/SAM
SHORT TERM...AJZ/MAM
LONG TERM...JAO
AVIATION...LKB
MARINE...MAS/JAO
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1037 AM CDT FRI MAY 15 2015
.UPDATE...
MAIN CHANGES TO FORECAST FOR TODAY ARE TO INCREASE POPS.
&&
.SHORT TERM...
MORNING OBSERVATIONAL DATA DEPICT AN ANOMALOUSLY MOIST AIRMASS
ACROSS REGION...PARTICULARLY IN LOWER LEVELS WITH LOWER 70S DEWPOINTS
AND 330-335 850 MB THETA-E VALUES. CONVECTION IS ALREADY BEGINNING TO
DEVELOP FROM S MS INTO S LA WITH DAYTIME HEATING AND APPROACH OF WEAK
UPPER WAVE FROM TX. ALL SHORT RANGE GUIDANCE SUGGESTS THAT CONVECTION
WILL CONTINUE TO INCREASE IN COVERAGE THROUGH THE DAY AND PROPAGATE
NORTH DUE TO 15-20 KT LOW/MID LEVEL S/SW FLOW. THIS EXPECTED SCENARIO
AND HRRR QPF SUGGESTS WIDESPREAD COVERAGE OF SHRA/TSRA TODAY AND
HAVE INCREASED POPS TO SHOW LIKELY CATEGORY ALL AREAS. AS DISCUSSED
BY PREVIOUS SHIFT...PRESENCE OF THIS FLOW...INCLUDING 20-30 KT 500 MB
WINDS...ALONG WITH SBCAPE VALUES OF 2000-3000 J/KG SUGGESTS THAT
SOMEWHAT ORGANIZED CONVECTION WITH STRONG WIND GUSTS IS POSSIBLE.
HOWEVER GIVEN EARLY START TO CONVECTION AND WEAK DCAPE VALUES WILL
HOLD OFF ON MENTIONING ANY STRONG/SEVERE ACTIVITY IN HWO OR GRAPHICS.
TEMPERATURE FORECAST LOOKS GOOD...HRRR SEEMS OVERAGGRESSIVE SHOWING
TEMPS REACHING LOWER 90S MOST AREAS CONSIDERING LOW LEVEL MOISTURE
AND EXPECTED CONVECTION. STUCK WITH ONGOING GRIDS. /AEG/
&&
.AVIATION...WHILE VFR CONDITIONS WILL EXIST FOR THE MOST PART THIS
AFTERNOON...SCATTERED TO NUMEROUS TSRA WILL EASILY ALLOW CIGS/VSBYS
TO BRIEFLY DROP TO MVFR. THESE CONDITIONS WILL LIKELY PERSIST UNTIL
02Z... DIMINISHING THEREAFTER. MVFR CIGS/VSBY WILL DEVELOP AFTER 06Z
WITH IFR CEILINGS DEVELOPING AT HBG./26/
&&
.PREV DISCUSSION... /ISSUED 432 AM CDT FRI MAY 15 2015/
DISCUSSION...
TODAY THROUGH SATURDAY NIGHT...A SUBTROPICAL RIDGE WILL CONTINUE TO
BE CENTERED OVER THE SOUTH ATLANTIC STATES AS WE GO INTO THE WEEKEND.
TO THE WEST OF THE RIDGE OVER THE ARKLAMISS...WARM SOUTHERLY FLOW IN
THE LOW LEVELS JUXTAPOSED BY DISTURBED SOUTHWEST FLOW ALOFT WILL
SUPPORT A WARM/MOIST (PRECIPITABLE WATER > 1.75 INCHES) AND UNSTABLE
AIRMASS WITH SCATTERED MAINLY AFTERNOON THUNDERSTORM COVERAGE. IT IS
DIFFICULT TO FIND SPECIFIC FOCUSING MECHANISMS THAT SUPPORT GOING
WITH HIGHER THAN CHANCE POPS...BUT A SUBTLE UPPER LEVEL SHORTWAVE
TROUGH CURRENTLY APPROACHING THE ARKLATEX REGION MAY ENHANCE
ACTIVITY LATER TODAY OVER THE FORECAST AREA. AND THEN FOR
SATURDAY...SLIGHTLY INCREASED SOUTHERLY FLOW AND LOW LEVEL
CONVERGENCE MAY ALSO RESULT IN GREATER COVERAGE WITH SOMEWHAT
FAVORABLE UPPER LEVEL DIVERGENCE REMAINING IN PLACE.
WHILE DEEP LAYER SHEAR IS NOT FORECAST TO BE FAVORABLE FOR ORGANIZED
SEVERE WEATHER...THERE SHOULD BE ENOUGH FLOW FOR MULTICELL LINE
SEGMENTS WITH LOW LEVEL FLOW SUPPORTING A FEW STRONG WIND
GUSTS...ESPECIALLY IN AREAS WHERE STORMS MOVE IN DURING TIME OF PEAK
HEATING AND MAXIMUM INSTABILITY. MOREOVER...THIS FLOW WOULD HELP TO
INCREASE STORM MOTIONS AND OVERALL RAINFALL COVERAGE. /EC/
SUNDAY THROUGH THURSDAY NIGHT...THE WARM AND HUMID CONDITIONS WILL
CONTINUE ON SUNDAY WITH ANOTHER ROUND OF DIURNAL CONVECTION AS THE
AREA CONTINUES TO BE SANDWICHED IN BETWEEN MID LEVEL RIDGING TO THE
EAST AND TROUGHING TO THE WEST. SUNDAY NIGHT THE RIDGE WILL BREAK
DOWN AS MID LEVEL TROUGHING DEEPENS OVER THE EASTERN PLAINS AND
DRIVES A COLD FRONT SOUTH ACROSS THE AREA ON MONDAY. EXPECT ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS ON MONDAY AS THE COLD FRONT MOVES
INTO THE AREA. THE ECMWF IS A LITTLE SLOWER WITH THE BOUNDARY MOVING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...BUT EITHER WAY EXPECT A
CONTINUATION OF THE WET PATTERN ON TUESDAY. BOTH THE GFS/ECMWF BUILD
SURFACE HIGH PRESSURE RIDGING AND A LITTLE DRIER AIR IN ON WEDNESDAY
AND THEN BRING ANOTHER COLD FRONT ACROSS THE AREA ON THURSDAY WITH
MORE SHOWERS AND THUNDERSTORMS. IT MOST DEFINITELY LOOKS LIKE WE WILL
HAVE FORGOTTEN ABOUT THE DRY WEATHER AS OF LATE BY THE END OF THE
LONG TERM./15/
AVIATION...SCATTERED AREAS OF IFR STRATUS SHOULD DEVELOP EARLY THIS
MORNING...ESPECIALLY IN THE HBG AREA...BUT FLOW THUS FAR HAS BEEN
STRONG ENOUGH TO SLOW DOWN FOG DEVELOPMENT. SCATTERED DIURNAL SHRA/TSRA
WILL POTENTIALLY AFFECT ALL SITES THIS AFTN INTO EARLY EVNG IN THE
WARM/MOIST AND UNSTABLE AIRMASS. MOST RECENT SREF GUIDANCE SUGGESTS
BETTER POTENTIAL FOR LOW CIGS TO DEVELOP EARLY SATURDAY MORNING WITH
INCREASING SOUTHERLY FLOW. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 85 69 83 70 / 63 42 56 38
MERIDIAN 86 69 83 69 / 63 41 61 40
VICKSBURG 86 71 84 71 / 59 44 53 33
HATTIESBURG 86 70 83 70 / 70 30 58 40
NATCHEZ 85 70 84 71 / 62 40 52 36
GREENVILLE 87 71 83 71 / 65 49 59 38
GREENWOOD 86 70 82 70 / 64 49 58 40
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG/26
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
235 PM CDT Fri May 15 2015
...Unsettled Weather This Weekend Followed By Cooler Weather Again
Early Next Week...
.SHORT TERM...(This Evening through Saturday)
Issued at 222 PM CDT FRI MAY 15 2015
A weak impulse is currently moving across the Missouri Ozarks and
lifting northeastward. Scattered convection has developed ahead of
the impulse across central Missouri and the eastern Ozarks where
instability is better. This convection will continue to move
northward. There appears to be a little subsidence behind the
exiting upper level impulse. Additional isolated to widely scattered
convection is possible elsewhere through the evening hours where the
sun is able to add some instability but it will be limited. Short range
models like the HRRR and RUC13 keep most of the convection
redevelopment towards central Missouri this evening.
Later this evening...for the most part the weather should be fairly
quiet. Will mention the possibility of some patchy fog near large
lakes and river valleys by sunrise in the morning. Forecast cape for
tomorrow approach 2500 J/KG but the deep shear will be limited
around 20 to 25 knots for most of the day over the Ozarks. The
better dynamics will be just to our west across Kansas and Oklahoma
for severe convection. Scattered convection will develop around the
Missouri Ozarks by midday to afternoon on Saturday with the best
potential over south central Missouri.
Models indicate that the leftover severe convection that develops
across Kansas and Oklahoma will move into southeast Kansas and
extreme western Missouri late Saturday evening and overnight. There
is a slight risk for severe weather Saturday evening for these areas
with the main threat being damaging wind gusts and large hail.
MUCape will be between 1500 to 2000 J/KG with Bulk shear values
increasing to 40 knots by Saturday evening over southeast Kansas
and western Missouri. Line segments and clusters of convection is
expected moving eastward from Kansas and Oklahoma into the western
Missouri Ozarks. Total QPF this weekend is expected on average
between 0.5 to 1.0 of an inch.
.LONG TERM...(Sunday through Friday)
Issued at 222 PM CDT FRI MAY 15 2015
The main upper level support and energy moves away from the area on
Sunday and Sunday night. Models indicate the best potential for
additional convection develop on Sunday afternoon and evening will be
south and east of I-44 across south central Missouri. There is a
very limited potential for a couple strong storms over south central
Missouri Sunday evening. A cold front finally makes some progress
into the area by Monday. There will be a chance for showers and
storms across south central Missouri before the front clears through
the area.
Cool and drier air will move in for Monday night through Tuesday
evening. Temperatures will be below average. The weather pattern
becomes unsettled again by the middle and end of next week.
Another broad trough develops across the western U.S. and weak
shortwaves and impulses will move across the central Plains and
Midwest starting Wednesday through Friday with scattered rain
chances and thunderstorms.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1240 PM CDT FRI MAY 15 2015
For the KSGF, KJLN, and KBBG TAFS: Scattered showers and storms
will be possible across the area this afternoon into early this
evening. Storms are expected to develop, but with the scattered
nature of this activity covering the potions in the TAFS with
Tempo groups since they will not be widespread.
The convection should push east of the area overnight with mainly
dry conditions expected. MVFR ceilings will be possible early
Saturday morning with light fog possible at the KBBG TAF site.
Additional scattered showers and storms will be possible Saturday
morning but the better chances should remain south and west of the
area until the afternoon hours which is beyond this TAF period.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Wise
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
845 PM MDT SAT MAY 16 2015
.UPDATE...
NO MAJOR UPDATES TO THE FORECAST. DID RAISE POPS LITTLE ACROSS THE
EASTERN ZONES TO BETTER REFLECT THE ONGOING CONVECTION MOVING
ACROSS THE AREA. THE HRRR SHOWS THESE THUNDERSTORMS WEAKENING...BUT
SHOWERS WILL PERSIST AFTER MIDNIGHT. OTHERWISE...CONTINUING THE
POPS ACROSS THE WESTERN ZONES WITH THE WRAP AROUND SHOWERS AS THE
LOWER PRESSURE SYSTEM CONTINUE TO MOVE EAST ACROSS THE AREA.
REIMER
&&
.SHORT TERM...VALID FOR SUN AND MON...
CORE OF UPPER LOW CENTERED NEAR IDAHO FALLS THIS AFTERNOON WITH A
SHORT WAVE SPOKE OF ENERGY ROTATING THROUGH THE BOTTOM OF THE MAIN
TROUGH ACROSS NORTHERN NEW MEXICO. THIS IS PRODUCING A MORE
COMPLEX OVERALL PATTERN OF INSTABILITY THAN ONE MIGHT SUSPECT.
THE MAIN UPPER LOW HAS PRODUCED A DRY SLOT INTO SE MONTANA WHILE
COPIOUS MOISTURE WRAPS AROUND INTO NORTHERN AND WESTERN MONTANA.
THIS MOISTURE WILL EVENTUALLY WRAP AROUND INTO OUR WESTERN AND
CENTRAL ZONES AS THE UPPER LOW SHIFTS NORTH/NORTHEAST TONIGHT
THROUGH SUNDAY. SO INCREASING POPS FOR OUR FORECAST AREA TONIGHT
INTO SUNDAY STILL LOOKS GOOD.
IN THE MEANTIME...AN AXIS OF INSTABILITY IS MOVING NORTH THROUGH
WYOMING AND MAY VERY WELL END UP MERGING WITH THE WRAP AROUND
MOISTURE INTO OUR CENTRAL ZONES THIS EVENING. THIS AREA IS
HELPING TO PRODUCE ISOLATED THUNDERSTORMS IN NORTHERN
WYOMING...WHICH SHOULD SPREAD INTO SOUTHERN MONTANA BY EVENING. SO
WE WILL KEEP A MENTION OF THUNDER INTO THE EVENING.
A FEW OTHER NOTES...THE EXIT OF THE STORM SYSTEM FROM OUR REGION
LOOKS A LITTLE SLOWER ON THE RECENT PROGGS...SO HAVE HELD BACK
SOME POPS INTO SUNDAY EVENING. WE RECEIVED ABOUT 6 INCHES OF SNOW
IN A COUPLE OF LOCATIONS LAST NIGHT IN THE BEARTOOTHS...BUT THE
WEBCAMS SHOW SOME OF THAT MAY HAVE MELTED OFF TODAY.
HOWEVER...SNOWFALL RATES MAY BECOME RATHER INTENSE AGAIN TONIGHT
AS INSTABILITY AGAIN INCREASES WITH ABUNDANT MOISTURE SWINGING
AROUND INTO THE MOUNTAINS AGAIN BY EVENING. SO WE WILL KEEP THE
WINTER STORM WARNING GOING FOR THE ABSAROKA/BEARTOOTH MOUNTAINS.
COLD OVERNIGHT LOWS STILL ON TAP FOR LATE SUNDAY NIGHT AS CLOUDS
BREAK UP. BT
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MODELS IN GOOD AGREEMENT THROUGH THE UPCOMING WEEK. THERE ARE A
COUPLE OF SYSTEMS TO AFFECT THE AREA. THE FIRST SYSTEM IS AN UPPER
LOW WHICH WORKS INTO CENTRAL WYOMING TUESDAY NIGHT. THIS SYSTEM
WILL WEAKEN AS IT ENCOUNTERS THE SMALL SCALE RIDGE IN PLACE THAT
WILL PROVIDE A MAINLY DRY DAY FOR TUESDAY. WEAK DIFFLUENT FLOW
WILL SPREAD INTO THE FORECAST AREA THROUGH WEDNESDAY. THE LATEST
TREND HAS BEEN TO KEEP THE STRONGEST FORCING TO THE SOUTH. DID
TRIM POPS BACK A BIT WITH THIS IN MIND. EASTERLY LOW LEVEL FLOW
WILL KEEP THINGS FAIRLY COOL AND STABLE...ALTHOUGH WITH WEAKER
FORCING...RAISED HIGH TEMPERATURES A BIT THROUGH THURSDAY.
VERY WEAK FLOW WILL LINGER FOR THURSDAY AND FRIDAY AS THE NEXT
UPPER LOW MOVES INTO NEVADA. WEAK UPSLOPE FLOW...WEAK ENERGY...AND
LEFT OVER MOISTURE FROM PREVIOUS SYSTEMS...WILL LEND TO ISOLATED
TO SCATTERED POPS THURSDAY AND FRIDAY. THE NEVADA UPPER LOW SLOWLY
WORKS INTO WYOMING ON SATURDAY AND THIS WILL PROVIDE ENOUGH
FORCING TO KEEP POPS GOING. OVERALL...LOOKS LIKE A UNSETTLED
PATTERN...ALTHOUGH WITH WEAK FORCING...WIDESPREAD HEAVY RAIN
POTENTIAL LOOKS LIMITED. TWH
&&
.AVIATION...
AREAS OF RAIN WILL CONTINUE THROUGHOUT THE NIGHT WITH SOME
EMBEDDED THUNDERSTORMS THROUGH 06Z. MVFR CONDITIONS CAN BE
EXPECTED WITH IFR CONDITIONS IN THE HEAVIER SHOWERS. THE MAIN
FOCUS OF PRECIPITATION WILL BE WEST OF A LINE FROM KMLS TO KSHR.
THE MOUNTAINS WILL CONTINUE TO SEE SNOW. SOME OF THE SNOW WILL BE
HEAVY AND THE MOUNTAINS WILL BE MOSTLY OBSCURED THROUGH THE NIGHT.
HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 042/046 035/053 038/059 040/057 041/063 043/063 045/065
88/W 41/E 01/E 44/W 32/W 33/W 33/W
LVM 039/051 033/052 034/057 038/057 037/062 039/062 041/063
97/W 22/W 12/W 33/W 33/W 34/W 44/W
HDN 042/048 034/057 037/061 040/060 039/066 043/066 045/068
88/W 41/E 01/E 33/W 31/B 33/W 33/W
MLS 045/046 032/053 034/058 039/060 039/064 043/064 047/068
46/W 40/B 01/B 33/W 21/B 22/W 33/W
4BQ 045/050 032/054 035/056 038/057 038/062 043/062 047/067
46/W 30/B 02/W 54/W 21/B 23/W 33/W
BHK 044/047 028/052 029/055 036/057 037/060 040/061 044/064
46/W 41/B 01/B 34/W 21/B 22/W 22/W
SHR 040/048 032/055 036/057 038/057 037/063 041/063 042/064
76/W 31/E 03/W 44/W 42/W 34/W 44/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 6 PM MDT SUNDAY ABOVE
7000 FEET FOR ZONE 67.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
629 PM CDT SAT MAY 16 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 332 PM CDT SAT MAY 16 2015
SEVERE POTENTIAL TONIGHT REMAINS THE PRIMARY FORECAST CONCERN.
SCATTERED CONVECTION SUNDAY FOLLOWED BY COOLER TEMPERATURES TO BEGIN
THE WORK WEEK ARE SECONDARY CONCERNS.
18Z SOUNDING AT KOAX SHOWED ALMOST 1500 J/KG OF SURFACE-BASED
CAPE...WHICH IS MUCH LOWER THAN THE 2500 J/KG SHOWN BY OPERATIONAL
RAP ANALYSIS OBSERVED ON SPC MESOANALYSIS PAGE. SOUNDING ALSO SHOWED
ALMOST 50 J/KG OF CONVECTIVE INHIBITION. HOWEVER AXIS OF HIGHEST
CAPE NEAR OUR CWA DEPICTED BY RAP STILL LOOKS GOOD STRETCHING FROM
EASTERN SOUTH DAKOTA INTO WESTERN IOWA WHERE AVERAGE TEMPS AND DEW
POINTS WERE IN THE UPPER 70S AND UPPER 60S. EXPERIMENTAL HRRR
SUGGESTS A FEW STORMS WILL FIRE THIS AFTERNOON FROM SOUTHEAST SOUTH
DAKOTA INTO EASTERN NEBRASKA ON WESTERN SIDE OF INSTABILITY
GRADIENT...AND ALREADY ARE SEEING THE START OF THAT CONVECTION IN
SOUTH DAKOTA AND NEAR THE OMAHA METRO. THESE STORM SHOULD CONTINUE
TO MOVE OFF TO THE NORTHEAST RATHER QUICKLY...AND COULD SEE A
WIND/HAIL EVENT BEFORE EXITING OUR CWA LATE THIS AFTERNOON.
ATTENTION THEN TURNS TO POTENTIALLY MORE WIDESPREAD SEVERE IGNITING
WELL TO OUR SOUTHWEST IN THE HIGHS PLAINS FROM WESTERN NEBRASKA INTO
THE TEXAS PANHANDLE. HI-RES MODELS ALL HAVE SOME VARIATION IN THIS
CONVECTION...AND SPREAD IT INTO SOUTHEAST NEBRASKA LATER THIS
EVENING. WHAT KIND OF ATMOSPHERE WILL BE AVAILABLE FOR THOSE STORMS
IS STILL IN QUESTION...MAINLY DUE TO ON-GOING STORMS IN CENTRAL
KANSAS INTO NORTH CENTRAL OKLAHOMA. THE MOST LIKELY SCENARIO BASED
ON LATEST HRRR AND RAP IS SOME OF THE KANSAS CONVECTION WILL TRACK
NORTHEAST INTO EASTERN NEBRASKA LATE THIS AFTERNOON THEN EXIT TO THE
EAST THIS EVENING. GIVEN CURRENT INSTABILITY AND SHEAR...ROTATING
STORMS ARE LIKELY WITH AT LEAST SOME HAIL THREAT AND MOST NOTABLY
WIND. TORNADOES ARE STILL A THREAT AS WELL IF FORECAST STORM-
RELATIVE 0-1KM HELICITY NEAR 150 M2/S2 IS REALIZED. MODELS DEPICT
THIS AREA OF CONVECTION WILL BOW OUT ACROSS WESTERN IOWA BEFORE
EXITING TO OUR EAST.
THEN SECONDARY SURGE OF STORMS IS SLATED TO RACE NORTHEAST FROM
OKLAHOMA PANHANDLE AND ENTER SOUTHEAST NEBRASKA AT MID TO LATE
EVENING. SOME RECOVERY IN AIRMASS IS LIKELY AFTER EARLIER STORMS. AN
INCREASE IN LOW LEVEL JET TO NEAR 50KT IS LIKELY AS INCREASINGLY
DIFFLUENT MID LEVEL FLOW OVERSPREADS THE PLAINS. SO LATER-EVENING
STORMS WILL STILL HAVE VIGOROUS WIND FIELDS TO PLAY WITH...
SUPPORTING AT LEAST SOME TORNADO AND WIND THREAT PAST DARK. TREND IN
HOURLY UPDATES OF HRRR FORECASTS HAS BEEN FOR NORTHERNMOST SEVERE
STORMS TO ONLY GRAZE FAR SOUTHEAST NEBRASKA IN THE 03Z TO 06Z
TIMEFRAME. SO WILL KEEP A CLOSE EYE ON IF THIS TREND CONTINUES.
WHILE SECOND LINE OF STORMS MOVES EAST OF OUR CWA AFTER
MIDNIGHT...MORE SHOWERS/STORMS ARE FORECAST TO DEVELOP IN WESTERN
NEBRASKA AND TRACK INTO NORTHEAST NEBRASKA OVERNIGHT AS UPPER LOW
MOVES INTO THE NORTHERN PLAINS. A WAVE ROTATING AROUND THIS FEATURE
WILL LIKELY IGNITE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MUCH
OF SUNDAY IN SOUTH DAKOTA AND NORTHERN NEBRASKA. GFS SUGGESTS UP TO
1000 J/KG OF SURFACE-BASED CAPE WILL BE AVAILABLE FOR THIS ACTIVITY
INTO THE AFTERNOON.
AFTER WAVE PASSES SUNDAY AFTERNOON...STRONG COLD ADVECTION WILL
OVERSPREAD OUR AREA...DROPPING 850 TEMPERATURES TO BELOW 0C ON
MONDAY IN OUR NORTH. COULD SEE A PASSING SHOWER ALONG THIS COLD PUSH
SUNDAY NIGHT...BUT THE MAIN WEATHER STORY WILL BE COOLER AND DRIER
AIR BEING PUSHED INTO THE REGION ON BRISK NORTHWEST WINDS MONDAY.
HIGHS IN THE LOWER 60S SHOULD BE ALL WE CAN MUSTER THEN. THE COOL
WEATHER CONTINUES INTO TUESDAY WHEN SURFACE HIGH PRESSURE SETTLES
INTO THE REGION. COULD SEE SUB-40 LOWS IN MANY AREAS TUESDAY MORNING.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CDT SAT MAY 16 2015
MID LEVEL FLOW PATTERN WILL RELOAD AS ANOTHER UPPER LOW SETTLES INTO
THE SOUTHWEST STATES AT MID WEEK ON HEELS OF EXITING NORTHERN PLAINS
LOW. THIS WILL BRING GENERALLY SOUTHWEST FLOW OVER THE MIDDLE OF THE
COUNTRY...WITH A POTENT WAVE EJECTING INTO THE PLAINS ON WEDNESDAY.
THAT WAVE WILL BRING OUR NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
BEGINNING TUESDAY NIGHT BEFORE EXITING WEDNESDAY NIGHT. MOISTURE
RETURN LOOKS MINIMAL...SO SEVERE STORMS APPEAR UNLIKELY DESPITE THE
CALENDAR SAYING WE ARE IN MID TO LATE MAY.
SOME WEAK RIDGING BEHIND EXITING WAVE SUGGESTS RAIN CHANCES WILL BE
AT A MINIMUM TO END THE WEEK...BUT SOUTHWESTERN TROUGH AXIS BEGINS
LIFTING TOWARD THE PLAINS BY SATURDAY. WILL BRING STORM CHANCES BACK
INTO THE FORECAST THEN...BUT DETAILS WILL HAVE TO BE WORKED OUT WITH
TIME ON DEGREE OF POTENTIAL SEVERE RISK.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 619 PM CDT SAT MAY 16 2015
REGIONAL RADAR MOSAIC SHOWING LARGE AREA OF TSRA OVER ERN KS
QUICKLY LIFTING INTO SERN NEB. EXPECT ACTIVITY/MVFR CONDITIONS TO
MOVE INTO KLNK/KOMA AROUND 01Z...THEN KOFK AROUND 02Z. MAIN THREAT
AT THIS POINT APPEARS TO BE PERIODS OF HVY RA THRU ABOUT MIDNIGHT.
AS UPPER LVL DISTURBANCE LIFTS INTO THE DAKOTAS THEN...EXPECT VFR
CONDITIONS TO RETURN AND PREVAIL THE DURATION OF THE FCST PD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...DEE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
115 PM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CDT FRI MAY 15 2015
TODAY AND TONIGHT... A WEAK COLD FRONT HAS DROPPED SOUTH TO JUST
NORTH OF INTERSTATE 80 PER SFC OBS AND RTMA ANALYSIS. EAST WINDS ARE
UNDERWAY IN THE PLATTE VALLEY. STRATUS NORTH OF THE FRONT ACROSS NRN
NEB COULD SPREAD SOUTH TO NEAR THEDFORD AND PERHAPS AS FAR SOUTH AS
BROKEN BOW BY MORNING. THE THUNDERSTORMS UNDERWAY ACROSS SWRN NEB
THIS MORNING SHOULD MOVE UP AND OVER THE FRONT PRODUCING RAIN COOLED
AIR WHICH WOULD KEEP THE FRONT IN OR NEAR THE PLATTE VALLEY UNTIL
AFTERNOON. THIS AFTERNOON...FRONT COULD BEGIN TO MOVE NORTH SLOWLY.
THE MODEL CONSENSUS SHOWS THE FRONT LIFTING RAPIDLY NORTH TONIGHT.
THE BEST GUESS ON THE SEVERE WEATHER IS A BIT OPTIMISTIC. STRONG
WINDS ALOFT...40 TO 50 KT AT 500 MB AND 60 KT AT 300 MB SHOULD MOVE
INTO SWRN NEB AROUND 18Z AND FIRE CONVECTION ON A WARM FRONT DRAPED
ACROSS THE SRN SANDHILLS BY 21Z...PERHAPS ALIGNED E-SE TOWARD
LEXINGTON. THE RAP SHOWS LARGE SCALE LIFT AT THE SAME TIME EMANATING
FROM A LONG WAVE TROF OVER THE SWRN U.S.
TORNADO PARAMETERS LOOK REASONABLY GOOD WITH NICELY CURVED
HODOGRAPHS NEAR THE FRONT FOR SEVERAL HOURS DURING THE AFTN. THIS
PRODUCES 0-3KM HELICITY OVER 400 M2/S2 AND WHEN COMBINED WITH THE
INSTABILITY THE ENERGY HELICITY INDEX IS OVER 4 ALONG THE FRONT.
THUS A TORNADO OR TWO COULD FORM. WINDS ALOFT ARE A BIT LINEAR AND
CONRAD CONTINUES TO SUGGEST SPLITTING DOMINANT RIGHT MOVING
SUPERCELLS.
NOTE THE RAP...THE FAVORED MODEL...MOVES THE FRONT VERY LITTLE TODAY
WHICH COULD ALLOW FOR SEVERE STORMS TO RIDE UP AND OVER THE FRONT
AND BECOME MORE OF A HAIL THREAT.
SPC SUGGESTED STORM ACTIVITY WOULD WEAKEN THIS EVENING AND IT IS
POSSIBLE THE LARGE SCALE LIFT AND UPPER LEVEL SUPPORT COULD DO THE
SAME CARRYING THE BULK OF THE STORM ACTION INTO NRN NEB BY 00Z AS
SUGGESTED BY THE MODEL CONSENSUS.
THE FORECAST USES A BLEND OF THE RAP...NAM...GEMREG...ARW AND NMM.
THE OTHER MODELS WERE TOO COARSE RESOLUTION TO CAPTURE THE SPIRIT OF
THE EVENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 323 AM CDT FRI MAY 15 2015
DETERMINISTIC MODELS AND ENSEMBLE MEANS CONTINUE TO ADVERTISE A
PERSISTENT UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT
WEEK. BLOCKY SETUP ALONG THE WEST COAST INTO THE CENTRAL ROCKIES
WITH A HIGH AMPLITUDE RIDGE OVER WESTERN CANADA OVER THE TOP OF A
BROAD TROUGH EXTENDING SOUTHWARD TOWARD THE BAJA OF CALIFORNIA.
RIDGE TO THE EAST WILL BEGIN TO FLATTEN INTO EARLY NEXT WEEK AS A
LOW BUILDS INTO SOUTHEAST CANADA. THE MEAN UPPER LEVEL FLOW OVER THE
CENTRAL PLAINS REMAINS OUT OF THE SOUTHWEST THROUGH THE LONG RANGE
PERIOD AND IN THE CROSSHAIRS OF SEVERAL SHORTWAVE PERTURBATIONS
ASSOCIATED WITH THE WESTERN CONUS TROUGH.
ANOTHER ROUND OF SEVERE WEATHER IS POSSIBLE AGAIN ON SATURDAY AS
STRONG PV MAX AND UPPER LEVEL JET STREAK EJECT NORTHEAST OUT OF THE
FOUR CORNERS REGION. LEE SIDE LOW AND ASSOCIATED PACIFIC FRONT MAKE
LITTLE EASTWARD PROGRESSION TOWARD THE EASTERN NEBRASKA PANHANDLE BY
THE BEGINNING OF THE PERIOD. SCATTERED ELEVATED STORMS LEFTOVER FROM
FRIDAY NIGHT SHOULD BE PUSHING NORTH AND EAST OF THE CWA DURING THE
MORNING HOURS...AIDED BY A VEERING LLJ. CONVECTIVE INITIATION IS
LIKELY ONCE AGAIN BY MID AFTERNOON IN AN INCREASINGLY UNSTABLE WARM
SECTOR EAST OF THE PACIFIC FRONT. MODELS ARE STRUGGLING WITH THEIR
HANDLING OF WARM SECTOR RECOVERY...AND ANY CLOUD COVER WILL HAVE A
SIGNIFICANT IMPACT ON THE DEGREE OF DESTABILIZATION. HOWEVER SEVERE
STORMS WILL STILL BE POSSIBLE GIVEN THE STRONG FORCING FOR ASCENT
AND FAVORABLE DEEP LAYER SHEAR. WIND PROFILES CONTINUE TO LOOK
FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...FAVORING
UPSCALE GROWTH AS THE THUNDERSTORM ACTIVITY EVOLVES THROUGH THE
AFTERNOON AND EVENING. LARGE HAIL...DAMAGING WINDS WILL BE THE
PRIMARY THREATS. LOCALLY HEAVY RAINFALL WILL ALSO NEED TO BE CLOSELY
WATCHED AS SOME AREAS MAY EXPERIENCE SEVERAL ROUNDS/TRAINING
THUNDERSTORMS.
SHOWER AND THUNDERSTORM CHANCES CONTINUE SUNDAY ACROSS THE NORTHERN
TIER OF THE CWA. LOW LEVEL MOISTURE WRAPS AROUND THE BACKSIDE OF THE
SFC LOW NOW OVER THE DAKOTAS AND BACK INTO NEBRASKA...UNDERNEATH
ANOMALOUSLY COLD AIR ALOFT ASSOCIATED WITH THE PASSING OF THE
UPPER LEVEL LOW. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS
EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS.
THE MIDDLE OF THE WEEK LOOKS COOL AND WET AS ANOTHER UPPER LEVEL
SHORTWAVE TROUGH PIVOTS NORTHEAST THROUGH THE EASTERN ROCKIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 115 PM CDT FRI MAY 15 2015
MOST OF THE AREA BECOMING VFR AS SHOWERS LIFT INTO S DAKOTA. A FEW
POCKETS OF MVFR/IFR CIGS...MAINLY ACROSS NORTHERN NEBRASKA. THIS
EVENING THUNDERSTORMS ARE LIKELY TO DEVELOP AND LIFT NORTHEAST
ACROSS THE AREA. DEVELOPMENT NEAR KLBF AND ONLY INCLUDED VCTS FOR
NOW AND WILL AMEND AS DEVELOPMENT OCCURS. HIGHER CONFIDENCE OF
THUNDERSTORMS ACROSS NORTHERN NEBRASKA AND INCLUDED A TEMPO FOR
KVTN. ALSO GOING TO SEE INCREASING SOUTHEASTERLY WINDS FOR THE
AFTERNOON.
AFTER STORMS LIFT NORTH OVERNIGHT EXPECT A LULL IN THE ACTIVITY
INTO TOMORROW MORNING. HOWEVER SOME AREAS OF STRATUS COULD
DEVELOP AND IMPACT THE TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...MASEK
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
641 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CDT FRI MAY 15 2015
TODAY AND TONIGHT... A WEAK COLD FRONT HAS DROPPED SOUTH TO JUST
NORTH OF INTERSTATE 80 PER SFC OBS AND RTMA ANALYSIS. EAST WINDS ARE
UNDERWAY IN THE PLATTE VALLEY. STRATUS NORTH OF THE FRONT ACROSS NRN
NEB COULD SPREAD SOUTH TO NEAR THEDFORD AND PERHAPS AS FAR SOUTH AS
BROKEN BOW BY MORNING. THE THUNDERSTORMS UNDERWAY ACROSS SWRN NEB
THIS MORNING SHOULD MOVE UP AND OVER THE FRONT PRODUCING RAIN COOLED
AIR WHICH WOULD KEEP THE FRONT IN OR NEAR THE PLATTE VALLEY UNTIL
AFTERNOON. THIS AFTERNOON...FRONT COULD BEGIN TO MOVE NORTH SLOWLY.
THE MODEL CONSENSUS SHOWS THE FRONT LIFTING RAPIDLY NORTH TONIGHT.
THE BEST GUESS ON THE SEVERE WEATHER IS A BIT OPTIMISTIC. STRONG
WINDS ALOFT...40 TO 50 KT AT 500 MB AND 60 KT AT 300 MB SHOULD MOVE
INTO SWRN NEB AROUND 18Z AND FIRE CONVECTION ON A WARM FRONT DRAPED
ACROSS THE SRN SANDHILLS BY 21Z...PERHAPS ALIGNED E-SE TOWARD
LEXINGTON. THE RAP SHOWS LARGE SCALE LIFT AT THE SAME TIME EMANATING
FROM A LONG WAVE TROF OVER THE SWRN U.S.
TORNADO PARAMETERS LOOK REASONABLY GOOD WITH NICELY CURVED
HODOGRAPHS NEAR THE FRONT FOR SEVERAL HOURS DURING THE AFTN. THIS
PRODUCES 0-3KM HELICITY OVER 400 M2/S2 AND WHEN COMBINED WITH THE
INSTABILITY THE ENERGY HELICITY INDEX IS OVER 4 ALONG THE FRONT.
THUS A TORNADO OR TWO COULD FORM. WINDS ALOFT ARE A BIT LINEAR AND
CONRAD CONTINUES TO SUGGEST SPLITTING DOMINANT RIGHT MOVING
SUPERCELLS.
NOTE THE RAP...THE FAVORED MODEL...MOVES THE FRONT VERY LITTLE TODAY
WHICH COULD ALLOW FOR SEVERE STORMS TO RIDE UP AND OVER THE FRONT
AND BECOME MORE OF A HAIL THREAT.
SPC SUGGESTED STORM ACTIVITY WOULD WEAKEN THIS EVENING AND IT IS
POSSIBLE THE LARGE SCALE LIFT AND UPPER LEVEL SUPPORT COULD DO THE
SAME CARRYING THE BULK OF THE STORM ACTION INTO NRN NEB BY 00Z AS
SUGGESTED BY THE MODEL CONSENSUS.
THE FORECAST USES A BLEND OF THE RAP...NAM...GEMREG...ARW AND NMM.
THE OTHER MODELS WERE TOO COARSE RESOLUTION TO CAPTURE THE SPIRIT OF
THE EVENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 323 AM CDT FRI MAY 15 2015
DETERMINISTIC MODELS AND ENSEMBLE MEANS CONTINUE TO ADVERTISE A
PERSISTENT UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT
WEEK. BLOCKY SETUP ALONG THE WEST COAST INTO THE CENTRAL ROCKIES
WITH A HIGH AMPLITUDE RIDGE OVER WESTERN CANADA OVER THE TOP OF A
BROAD TROUGH EXTENDING SOUTHWARD TOWARD THE BAJA OF CALIFORNIA.
RIDGE TO THE EAST WILL BEGIN TO FLATTEN INTO EARLY NEXT WEEK AS A
LOW BUILDS INTO SOUTHEAST CANADA. THE MEAN UPPER LEVEL FLOW OVER THE
CENTRAL PLAINS REMAINS OUT OF THE SOUTHWEST THROUGH THE LONG RANGE
PERIOD AND IN THE CROSSHAIRS OF SEVERAL SHORTWAVE PERTURBATIONS
ASSOCIATED WITH THE WESTERN CONUS TROUGH.
ANOTHER ROUND OF SEVERE WEATHER IS POSSIBLE AGAIN ON SATURDAY AS
STRONG PV MAX AND UPPER LEVEL JET STREAK EJECT NORTHEAST OUT OF THE
FOUR CORNERS REGION. LEE SIDE LOW AND ASSOCIATED PACIFIC FRONT MAKE
LITTLE EASTWARD PROGRESSION TOWARD THE EASTERN NEBRASKA PANHANDLE BY
THE BEGINNING OF THE PERIOD. SCATTERED ELEVATED STORMS LEFTOVER FROM
FRIDAY NIGHT SHOULD BE PUSHING NORTH AND EAST OF THE CWA DURING THE
MORNING HOURS...AIDED BY A VEERING LLJ. CONVECTIVE INITIATION IS
LIKELY ONCE AGAIN BY MID AFTERNOON IN AN INCREASINGLY UNSTABLE WARM
SECTOR EAST OF THE PACIFIC FRONT. MODELS ARE STRUGGLING WITH THEIR
HANDLING OF WARM SECTOR RECOVERY...AND ANY CLOUD COVER WILL HAVE A
SIGNIFICANT IMPACT ON THE DEGREE OF DESTABILIZATION. HOWEVER SEVERE
STORMS WILL STILL BE POSSIBLE GIVEN THE STRONG FORCING FOR ASCENT
AND FAVORABLE DEEP LAYER SHEAR. WIND PROFILES CONTINUE TO LOOK
FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...FAVORING
UPSCALE GROWTH AS THE THUNDERSTORM ACTIVITY EVOLVES THROUGH THE
AFTERNOON AND EVENING. LARGE HAIL...DAMAGING WINDS WILL BE THE
PRIMARY THREATS. LOCALLY HEAVY RAINFALL WILL ALSO NEED TO BE CLOSELY
WATCHED AS SOME AREAS MAY EXPERIENCE SEVERAL ROUNDS/TRAINING
THUNDERSTORMS.
SHOWER AND THUNDERSTORM CHANCES CONTINUE SUNDAY ACROSS THE NORTHERN
TIER OF THE CWA. LOW LEVEL MOISTURE WRAPS AROUND THE BACKSIDE OF THE
SFC LOW NOW OVER THE DAKOTAS AND BACK INTO NEBRASKA...UNDERNEATH
ANOMALOUSLY COLD AIR ALOFT ASSOCIATED WITH THE PASSING OF THE
UPPER LEVEL LOW. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS
EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS.
THE MIDDLE OF THE WEEK LOOKS COOL AND WET AS ANOTHER UPPER LEVEL
SHORTWAVE TROUGH PIVOTS NORTHEAST THROUGH THE EASTERN ROCKIES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 640 AM CDT FRI MAY 15 2015
THE THUNDERSTORM COMPLEX UNDERWAY IS EXPECTED TO MOVE NORTH THIS
MORNING AND EXIT NORTHERN NEB AROUND 18Z. AT ABOUT THAT SAME
TIME...A STRONG UPPER LEVEL DISTURBANCE WILL BEGIN IMPOSING ON
SWRN NEB AND THE SRN PANHANDLE PRODUCING ANOTHER ROUND STRONG TO
SEVERE STORMS WHICH WOULD ALSO LIFT NORTH DURING THE AFTN AND
EARLY EVENING.
THE RAP/NAM/GFS SUGGESTS THE IFR/LIFR ACROSS NCNTL NEB WILL
IMPROVE TO MVFR LATER THIS MORNING AND PERHAPS VFR THIS AFTN. VFR
IS EXPECTED AFTER 06Z TONIGHT EXCEPT THE NAM IS PRODUCING TSTMS
NEAR AND SOUTH OF KLBF 06Z-12Z SATURDAY MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CDT FRI MAY 15 2015
TODAY AND TONIGHT... A WEAK COLD FRONT HAS DROPPED SOUTH TO JUST
NORTH OF INTERSTATE 80 PER SFC OBS AND RTMA ANALYSIS. EAST WINDS ARE
UNDERWAY IN THE PLATTE VALLEY. STRATUS NORTH OF THE FRONT ACROSS NRN
NEB COULD SPREAD SOUTH TO NEAR THEDFORD AND PERHAPS AS FAR SOUTH AS
BROKEN BOW BY MORNING. THE THUNDERSTORMS UNDERWAY ACROSS SWRN NEB
THIS MORNING SHOULD MOVE UP AND OVER THE FRONT PRODUCING RAIN COOLED
AIR WHICH WOULD KEEP THE FRONT IN OR NEAR THE PLATTE VALLEY UNTIL
AFTERNOON. THIS AFTERNOON...FRONT COULD BEGIN TO MOVE NORTH SLOWLY.
THE MODEL CONSENSUS SHOWS THE FRONT LIFTING RAPIDLY NORTH TONIGHT.
THE BEST GUESS ON THE SEVERE WEATHER IS A BIT OPTIMISTIC. STRONG
WINDS ALOFT...40 TO 50 KT AT 500 MB AND 60 KT AT 300 MB SHOULD MOVE
INTO SWRN NEB AROUND 18Z AND FIRE CONVECTION ON A WARM FRONT DRAPED
ACROSS THE SRN SANDHILLS BY 21Z...PERHAPS ALIGNED E-SE TOWARD
LEXINGTON. THE RAP SHOWS LARGE SCALE LIFT AT THE SAME TIME EMANATING
FROM A LONG WAVE TROF OVER THE SWRN U.S.
TORNADO PARAMETERS LOOK REASONABLY GOOD WITH NICELY CURVED
HODOGRAPHS NEAR THE FRONT FOR SEVERAL HOURS DURING THE AFTN. THIS
PRODUCES 0-3KM HELICITY OVER 400 M2/S2 AND WHEN COMBINED WITH THE
INSTABILITY THE ENERGY HELICITY INDEX IS OVER 4 ALONG THE FRONT.
THUS A TORNADO OR TWO COULD FORM. WINDS ALOFT ARE A BIT LINEAR AND
CONRAD CONTINUES TO SUGGEST SPLITTING DOMINANT RIGHT MOVING
SUPERCELLS.
NOTE THE RAP...THE FAVORED MODEL...MOVES THE FRONT VERY LITTLE TODAY
WHICH COULD ALLOW FOR SEVERE STORMS TO RIDE UP AND OVER THE FRONT
AND BECOME MORE OF A HAIL THREAT.
SPC SUGGESTED STORM ACTIVITY WOULD WEAKEN THIS EVENING AND IT IS
POSSIBLE THE LARGE SCALE LIFT AND UPPER LEVEL SUPPORT COULD DO THE
SAME CARRYING THE BULK OF THE STORM ACTION INTO NRN NEB BY 00Z AS
SUGGESTED BY THE MODEL CONSENSUS.
THE FORECAST USES A BLEND OF THE RAP...NAM...GEMREG...ARW AND NMM.
THE OTHER MODELS WERE TOO COARSE RESOLUTION TO CAPTURE THE SPIRIT OF
THE EVENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 323 AM CDT FRI MAY 15 2015
DETERMINISTIC MODELS AND ENSEMBLE MEANS CONTINUE TO ADVERTISE A
PERSISTENT UPPER LEVEL SYNOPTIC PATTERN THROUGH THE MIDDLE OF NEXT
WEEK. BLOCKY SETUP ALONG THE WEST COAST INTO THE CENTRAL ROCKIES
WITH A HIGH AMPLITUDE RIDGE OVER WESTERN CANADA OVER THE TOP OF A
BROAD TROUGH EXTENDING SOUTHWARD TOWARD THE BAJA OF CALIFORNIA.
RIDGE TO THE EAST WILL BEGIN TO FLATTEN INTO EARLY NEXT WEEK AS A
LOW BUILDS INTO SOUTHEAST CANADA. THE MEAN UPPER LEVEL FLOW OVER THE
CENTRAL PLAINS REMAINS OUT OF THE SOUTHWEST THROUGH THE LONG RANGE
PERIOD AND IN THE CROSSHAIRS OF SEVERAL SHORTWAVE PERTURBATIONS
ASSOCIATED WITH THE WESTERN CONUS TROUGH.
ANOTHER ROUND OF SEVERE WEATHER IS POSSIBLE AGAIN ON SATURDAY AS
STRONG PV MAX AND UPPER LEVEL JET STREAK EJECT NORTHEAST OUT OF THE
FOUR CORNERS REGION. LEE SIDE LOW AND ASSOCIATED PACIFIC FRONT MAKE
LITTLE EASTWARD PROGRESSION TOWARD THE EASTERN NEBRASKA PANHANDLE BY
THE BEGINNING OF THE PERIOD. SCATTERED ELEVATED STORMS LEFTOVER FROM
FRIDAY NIGHT SHOULD BE PUSHING NORTH AND EAST OF THE CWA DURING THE
MORNING HOURS...AIDED BY A VEERING LLJ. CONVECTIVE INITIATION IS
LIKELY ONCE AGAIN BY MID AFTERNOON IN AN INCREASINGLY UNSTABLE WARM
SECTOR EAST OF THE PACIFIC FRONT. MODELS ARE STRUGGLING WITH THEIR
HANDLING OF WARM SECTOR RECOVERY...AND ANY CLOUD COVER WILL HAVE A
SIGNIFICANT IMPACT ON THE DEGREE OF DESTABILIZATION. HOWEVER SEVERE
STORMS WILL STILL BE POSSIBLE GIVEN THE STRONG FORCING FOR ASCENT
AND FAVORABLE DEEP LAYER SHEAR. WIND PROFILES CONTINUE TO LOOK
FAIRLY UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...FAVORING
UPSCALE GROWTH AS THE THUNDERSTORM ACTIVITY EVOLVES THROUGH THE
AFTERNOON AND EVENING. LARGE HAIL...DAMAGING WINDS WILL BE THE
PRIMARY THREATS. LOCALLY HEAVY RAINFALL WILL ALSO NEED TO BE CLOSELY
WATCHED AS SOME AREAS MAY EXPERIENCE SEVERAL ROUNDS/TRAINING
THUNDERSTORMS.
SHOWER AND THUNDERSTORM CHANCES CONTINUE SUNDAY ACROSS THE NORTHERN
TIER OF THE CWA. LOW LEVEL MOISTURE WRAPS AROUND THE BACKSIDE OF THE
SFC LOW NOW OVER THE DAKOTAS AND BACK INTO NEBRASKA...UNDERNEATH
ANOMALOUSLY COLD AIR ALOFT ASSOCIATED WITH THE PASSING OF THE
UPPER LEVEL LOW. A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS
EARLY IN THE WEEK BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS.
THE MIDDLE OF THE WEEK LOOKS COOL AND WET AS ANOTHER UPPER LEVEL
SHORTWAVE TROUGH PIVOTS NORTHEAST THROUGH THE EASTERN ROCKIES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 645 PM CDT THU MAY 14 2015
MAIN FCST CHALLENGE IS TIMING OF TSRA FOR THE KLBF TAF AND
SOUTHERN PORTION OF THE AREA...AND POTENTIAL FOR STRATUS AND BR
FOR THE KVTN TAF SITE OVERNIGHT. FIRST FOR TSRA...ISOLD TSRA HAS
DEVELOPED IN EXTREME SW NEB BUT BELIEVE MORE DEVELOPMENT WILL BE
COMING AS LLJ DEVELOPS IN WRN KS INTO SW NEB TWD MIDNIGHT.
ISENTROIC LIFT IN CONCERT WITH INCREASING ELEVATED INSTABILITY AS
A RESULT OF THE LLJ WILL RESULT IN SCT TSRA DEVELOPMENT AND HAVE
INCLUDED IN KLBF TAF AFTER 06Z. THESE SHOULD MOVE NWD THROUGH THE
NIGHT THOUGH COVERAGE IS A BIT IN QUESTION AS LATEST FEW HRRR RUNS
HAVE SHOWN LIMITED COVERAGE IN SWRN NEB TONIGHT.
NEXT WILL BE POTENTIAL FOR BR/STRATUS OVERNIGHT FURTHER N. STRATUS
CURRENTLY JUST NORTH OF THE NEB/SD BORDER DOES HAVE SWD MOVEMENT
THOUGH ERRODING ON THE WEST SIDE AS INCREASING WRLY MID LEVEL FLOW
CONTINUES. HOWEVER...BELIEVE AFTER SUNSET SHOULD SEE MORE SWD
PROGRESSION AS RAP/NAM SUGGEST AND WOULD BE EXPECTED NORTH OF
DEVELOPING WARM FRONT. HAVE INCLUDED BR IN THE KVTN TAF OVERNIGHT
THOUGH DID NOT TAKE VSBY TO IFR OR BELOW YET. GFS-LAMP ALSO
SUGGEST S THIS SCENARIO...AND THIS IS A BIT OF A CHANGE SINCE THE
LAST TAF FOR KVTN.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS ELKO NV
342 PM PDT FRI MAY 15 2015
.SYNOPSIS...A PACIFIC STORM SYSTEM WILL BRING A COOL AND RAINY
SATURDAY TO NORTHEASTERN NEVADA. BENEFICIAL VALLEY RAIN AND
MOUNTAIN SNOW SHOWERS WILL CONTINUE THROUGH SUNDAY. THE MUCH
NEEDED WET PATTERN WILL CONTINUE THROUGH NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SUNDAY. EXPECT THE UNSETTLED WEATHER
PATTERN TO CONTINUE THROUGH THE SHORT TERM PERIOD.
INSTABILITY IS MEAGER TODAY...BUT EARLIER BREAKS IN THE CLOUDS
ALLOWED FROM SOME POCKETS OF HIGHER INSTABILITY TO DEVELOP.
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE
EVENING...BUT WILL TRANSITION TO ALL RAIN SHOWERS BY 06Z. SNOW
LEVELS WILL REMAIN HIGH. HAD A REPORT OF SNOW AROUND 7500FT IN THE
RUBY MTNS...BUT NO ACCUMULATION. ACCUMULATING SNOW WILL STAY
MOSTLY ABOVE THAT. WRAP AROUND PRECIP WILL INCREASE TONIGHT ACROSS
NORTHEASTERN NV AND PERSIST INTO SATURDAY. HRRR SHOWS THIS NICELY
AND AGREES WITH THE GFS/EURO ON THE PLACEMENT/MOVEMENT OF THIS
PRECIP.
SATURDAY AND SUNDAY....EXPECT ANOTHER ROUND OF SHOWERS AND
ISOLATED THUNDERSTORMS...WITH THE MAJORITY OF THE ACTION IN
EASTERN NV. AS THE LOW PULLS AWAY...WRAP AROUND SHOWERS WILL
CONTINUE TO SPREAD ACROSS NORTHEASTERN NEVADA. FORECAST MODELS
HINT AT SOME HEAVIER SHOWERS THROUGH SATURDAY EVENING. MOST PLACES
WILL SEE AROUND 0.25 INCHES...WITH SOME LOCALIZED LOCATIONS IN NE
NV SEEING UP TO AN INCH OF LIQUID. BY SUNDAY...THE NEXT SYSTEM
STARTS TO IMPACT THE WEATHER IN OUR CWA. WITH RESIDUAL MOISTURE
AND THE CONTINUED INCREASING MOISTURE...THUNDERSTORMS MAY BECOME
MORE WIDESPREAD.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY. THE MODELS ARE IN GOOD
AGREEMENT THAT A PERIOD OF WET WEATHER IS IN STORE FOR THE GREAT
BASIN DURING THIS FORECAST PERIOD. A COUPLE OF CLOSED UPPER LOWS
WILL MOVE ACROSS THE GREAT BASIN DURING THE PERIOD BRINGING SHOWERS
AND THUNDERSTORMS. THE FIRST UPPER LOW WILL MOVE ONTO THE CENTRAL CA
COAST SUNDAY NIGHT THEN SLOWLY MEANDER EASTWARD INTO NV BY TUESDAY
AND DEPART TO THE EAST BY EARLY WEDNESDAY. A SECOND UPPER LOW WILL
BE QUICK ON ITS HEELS MOVING INTO CENTRAL CA ON WEDNESDAY ENDING UP
OVER NV BY FRIDAY.
&&
.AVIATION...A LOW PRESSURE SYSTEM MOVING ACROSS THE REGION WILL
BRING SHOWERS AND ISOLATED THUNDERSTORMS DURING THE NEXT 24 HOURS.
CONDITIONS WILL GENERALLY REMAIN VFR, BUT OCCASIONAL MVFR
CONDITIONS WILL OCCUR UNDER THE HEAVIER SHOWERS.
&&
.FIRE WEATHER...CONTINUED STORMINESS WILL PERSIST THROUGH THE NEXT
WEEK OR SO. EXPECT AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS
EACH AFTERNOON. COVERAGE OF THUNDERSTORMS MAY INCREASE INTO EARLY
NEXT WEEK...BUT ALL STORMS WILL REMAIN WET. RH RECOVERIES EACH
NIGH/MORNING WILL BE GOOD...AS ABUNDANT MOISTURE/PRECIP
CONTINUES. EXPECT ROUNDS OF HIGH ELEVATION SNOW ABOVE 7000 FT
THROUGH TOMORROW...RISING TO ABOVE 8000-8500 FT NEXT WEEK.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
94/91/91
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
540 PM MDT SAT MAY 16 2015
.AVIATION...
00Z TAF CYCLE
RESIDUAL SCT SH AND ISOLD TS WILL REMAIN THROUGH THE EARLY/MID
EVENING HOURS DUE TO THE DEPARTING PACIFIC LOW. IMPACTS ARE MOST
LIKELY AT SAF. OTHERWISE PRETTY HIT AND MISS. GUSTY WINDS WILL
REMAIN THROUGH AROUND SUNSET...THEN GRADUALLY LESSENING
THEREAFTER. GUSTS BETWEEN 30 TO 45 KT POSSIBLE AT MANY OF THE
TERMINAL SITES...ESPECIALLY CENTRAL AND EASTERN LOCATIONS DURING
THIS PERIOD. WIND SPEEDS WONT BE NEARLY AS GUSTY SUNDAY. VFR CIGS
EXPECTED FOR MOST LOCATION FOLLOWING THE SH/TS DISSIPATION. CANT
RULE OUT SOME LOCALIZED FG FORMATION LATE TONIGHT ACROSS THE NC
MTNS/UPPER RIO GRANDE VALLEY AND WESTERN MOUNTAINS. USED VCFG AT
GUP/FMN AND SAF TO REFLECT THIS POSSIBILITY. BEST CHANCE IS
PROBABLY AT GUP. WILL UPDATE AS WE GET CLOSER TO THE PERIOD.
50
&&
.PREV DISCUSSION...325 PM MDT SAT MAY 16 2015...
.SYNOPSIS...
PRECIPITATION AND WINDS OVERALL SHOULD DECREASE TONIGHT...WITH QUIET
AND WARMER WEATHER SUNDAY. ANOTHER FRONT AND STORM SYSTEM WILL
COLLIDE BY MONDAY NIGHT AND TUESDAY...WITH ANOTHER WET AND COOLER
PERIOD...ESPECIALLY FOR LOCALES EXTENDING FROM THE RIO GRANDE VALLEY
EASTWARD ACROSS THE EASTERN PLAINS. DRYING EXPECTED THEREAFTER WITH
SOME WARMING BUT SOME STORMS WILL STILL BE POSSIBLE ACROSS AT LEAST
OVER THE FAR EASTERN PLAINS AND NORTHERN MOUNTAINS THE END OF NEXT
WEEK.
&&
.DISCUSSION...
PRECIPITATION AND WINDS OVERALL SHOULD DECREASE OVERNIGHT...BUT WITH
SOME POSSIBLE EXCEPTIONS. WIND ADVY SPOTTY AT BEST THIS AFTERNOON
AND STRONGEST GUSTS APPEAR TO HAVE BEEN CONVECTION
RELATED...HOWEVER...H7 WINDS INCREASE OVERNIGHT OVER PARTS OF THE
NORTHEAST AS THE UPPER LOW/TROF SWINGS OUT INTO THE PLAINS
STATES...SO WILL KEEP THE NPW GOING. WILL ALSO KEEP THE CURRENT WSW
AS IS...WITH GFS/NAM NOT INDICATING MUCH SNOW AFTER 00Z. THE HRRR ON
THE OTHER HAND...KEEPS SOME SNOW GOING OVER THE NRN SANGRE DE CRISTO
MTS...AND THE FORECAST MOIST W-NWLY BOUNDARY LAYER WINDS INTO THE
SANGRES COULD CONTINUE TO ACCUMULATE SOME SNOW INTO THE LATE
EVENING. ARRGH...WILL HAVE TO CONTINUE TO MONITOR...BUT GRIDS HAVE
ANOTHER 1 TO 3 INCHES IN THIS AREA TONIGHT...ALTHOUGH THAT WOULD BE
UNDERDONE IF HRRR IS RIGHT. BUT NO MODEL SEEMS TO BE DOING THAT WELL
TODAY.
DRIER AND WARMER SUNDAY INTO MONDAY. THEN ANOTHER WETTER AND COOLER
PERIOD MONDAY NIGHT THROUGH TUESDAY AS ANOTHER SYSTEM COMING FROM
THE WEST AND A FRONT FROM THE EAST COLLIDE TO PRODUCE WIDESPREAD
PRECIPITATION. TRIMMED DOWN POPULATED QPF WHICH TOTALED A LARGE
SWATH OF A COUPLE OF INCHES JUST MONDAY NIGHT ALONG THE CENTRAL MT
CHAIN TO THE PECOS VALLEY. BUT SOME GENEROUS AMOUNTS POSSIBLE
TUESDAY AS WELL AS THE UPPER SYSTEM SWINGS OVER NE NM. H7 TEMPS NOT
AS COLD AS WITH PRESENT SYSTEM SO NOT ANTICIPATING THE LOWER SNOW
LEVELS THAT HAVE BEEN OBSERVED TODAY.
LOTS OF VARIATION MID TO LATE NEXT WEEK...THE GFS IS DRIER AND WINDY
WHILE THE ECMWF IS WETTER THANKS TO A FRONT ON FRIDAY...SURPRISE. IN
ANY EVENT...THE UNSETTLED WEATHER PATTERN APPEARS TO CONTINUE INTO
THE MEMORIAL DAY WEEKEND.
&&
.FIRE WEATHER...
NO WIDESPREAD FIRE WEATHER CONCERNS THROUGH THE FORECAST PERIOD AS
THE WEATHER PATTERN CONTINUES TO FAVOR UNSETTLED...ACTIVE WEATHER
AND SEASONABLY COOLER THAN NORMAL TEMPERATURES.
CURRENT UPPER LEVEL TROUGH IS CROSSING NM THIS PM AND WILL SHIFT TO
THE EAST TONIGHT. SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
THE EVENING HOURS...MAINLY NORTH OF I 40. SHOWERS MAY LINGER OVER
THE NORTH LATE TONIGHT. RH RECOVERIES WILL BE GOOD TO EXCELLENT.
A MAINLY DRY DAY IS IN STORE SUNDAY AS A WEAK UPPER LEVEL RIDGE
MOVES OVER. DESPITE THE RIDGE...HIGH TEMPERATURES REMAIN BELOW
AVERAGE FOR MID MAY. MODELS INDICATING RESIDUAL MOISTURE WILL
COMBINE WITH DAYTIME HEATING TO PRODUCE A FEW SHOWERS AND MAYBE
THUNDERSTORMS OVER THE NORTHERN MOUNTAINS.
A BACK DOOR COLD FRONT WILL DROP SOUTH INTO THE NORTHEAST EAST
SUNDAY NIGHT. IT WILL STALL MONDAY BEFORE RACING SOUTH AND WEST
MONDAY NIGHT. STRONG EAST WINDS INTO THE RIO GRANDE VALLEY ARE
POSSIBLE. MEANWHILE THE NEXT UPPER LEVEL TROUGH WILL BE APPROACHING
MONDAY THEN SWEEP ACROSS THE STATE MONDAY NIGHT INTO TUESDAY. THE
COMBINATION OF LOW LEVEL MOISTURE BEHIND THE FRONT...INSTABILITY
FROM THE UPPER TROUGH...AND DEEP MOISTURE GETTING DRAWN NORTHWEST
INTO NM FROM TX WILL RESULT IN A SIGNIFICANT RAIN EVENT FOR MUCH OF
THE FORECAST AREA...WITH THE LEAST FAVORED AREA THE SOUTHWEST AND
THE MOST FAVORED AREA ALL OF THE EAST. ALL THE MODELS HAVE A FAIRLY
WIDESPREAD...SOAKING RAIN EVENT WITH ONE TO TWO INCH RAIN AMOUNTS
FOR THE EASTERN PLAINS AND LOCALLY UP TO THREE INCHES IN THE MONDAY
NIGHT THROUGH TUESDAY TIME PERIODS.
YET ANOTHER STORM WILL BE ORGANIZING OFF THE CA COAST LATER NEXT
WEEK. THE FAR EASTERN PLAINS WILL BE UNDER THE GUN FOR SHOWERS AND
STORMS WEDNESDAY INTO FRIDAY. A DRY LINE WILL WOBBLE BACK WEST AT
NIGHT AND TO THE EAST DURING THE DAY. ELSEWHERE SHOULD BE MOSTLY
DRY. ALL AREAS WILL REMAIN BELOW NORMAL. WINDS WILL BE ON THE
INCREASE NEXT FRIDAY AND SATURDAY. BRIEF CRITICAL FIRE WEATHER
CONDITIONS ARE NOT OUT OF THE QUESTION OVER THE SOUTHERN PORTION
OF THE MIDDLE RIO GRANDE VALLEY FRIDAY AFTERNOON.
A PORTION OF THE ABOVE MENTIONED STORM WILL CROSS NM SATURDAY WHILE
ANOTHER PORTION HANGS BACK OVER UT AND AZ. THIS LAZY TROUGH WILL
INCH ITS WAY EAST WHILE KEEPING SHOWERS AND STORMS IN THE FORECAST
FOR THE NORTH AND EAST LATE NEXT WEEKEND INTO EARLY THE FOLLOWING
WEEK. 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...
NMZ523-526-529>540.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR THE
FOLLOWING ZONES...NMZ510-511-513-514.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1048 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1044 PM CDT SAT MAY 16 2015
MAIN UPDATES HAVE BEEN TO SHOW THE DIMINISHING RAIN TREND FOR THE
NEXT SEVERAL HOURS AS PER THE HRRR. ADDITIONAL RAIN CHANCES ARRIVE
LATER TONIGHT INTO SUNDAY AS THE SURFACE LOW LIFTS TOWARDS EASTERN
NORTH DAKOTA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM CDT SAT MAY 16 2015
CONCERNS THIS FORECAST PERIOD INCLUDE SEVERE WEATHER POSSIBILITY
AND HEAVY RAIN. BY THE END OF THE SHORT TERM THE TRANSITION TO
MUCH COOLER WEATHER WITH SOME SNOW BEGINS TO BE SEEN.
AT 230 PM CDT...SURFACE LOW PRESSURE WAS CENTERED NEAR NORTHWEST
SOUTH DAKOTA WITH AN EAST WEST WARM FRONTAL BOUNDARY EXTENDED
ACROSS NORTH CENTRAL SOUTH DAKOTA. FLOW OVER THE WARM FRONT WAS
GENERATING SHOWERS AND SCATTERED THUNDERSTORMS FROM MOBRIDGE NORTH
TO NEAR MINOT AND NORTH TO THE CANADIAN BORDER.
CONCERNING SEVERE WEATHER POTENTIAL...AN 18Z KBIS SOUNDINGS WAS
CONDUCTED. HRRR FORECAST CAPE VALUES IN THE NEIGHBORHOOD OF 2000
ARE FORECAST TO POOL ACROSS SOUTH CENTRAL INTO SOUTHEAST NORTH
DAKOTA LATE THIS AFTERNOON AND EVENING. EXPECT THE SEVERE WEATHER
POTENTIAL TO EXTEND FROM BISMARCK EAST. TO THE WEST EXPECT MORE
ELEVATED THUNDERSTORMS.
LATE TONIGHT AND SUNDAY...AN UPPER LEVEL LOW SWINGS INTO EASTERN
SOUTH DAKOTA THEN TRACKS NORTHEAST AND SPREADS A LARGE AREA OF THE
RAINSHOWERS ACROSS THE EAST HALF OF THE STATE AND ESPECIALLY THE
JAMES RIVER VALLEY. ACROSS THE NORTH CENTRAL...COOLER AIR WILL
BEGIN A RAIN/SNOW CHANGE OVER. AS THE SURFACE LOW WRAPS UP NORTH
WINDS OF 25 TO 35 MPH WILL BE COMMON ACROSS CENTRAL NORTH DAKOTA
ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM CDT SAT MAY 16 2015
RAIN...SNOW AND COLD TEMPERATURES WILL HIGHLIGHT THE LONG TERM.
THE STORM IMPACTING NORTH DAKOTA SATURDAY AND SUNDAY WILL CONTINUE
TO INFLUENCE THE REGION THROUGH MONDAY. THE UPPER LEVEL LOW AND
SURFACE LOW WILL BECOME NEARLY VERTICALLY STACKED OVER EASTERN
NORTH DAKOTA SUNDAY NIGHT. THIS WILL LEAD TO ENHANCED LIFT AND
PRECIPITATION ACROSS PORTIONS OF CENTRAL AND EASTERN NORTH DAKOTA.
AS THE LOW PROPAGATES EASTWARD SUNDAY NIGHT INTO MONDAY...COLD
AIR WILL WRAP IN FROM THE NORTH. A STEADY RAIN WILL TRANSITION TO
SNOW FROM NORTHWEST TO SOUTHEAST SUNDAY NIGHT. IN ADDITION TO
TRANSITIONING RAIN TO SNOW...STRONG COLD AIR ADVECTION AND A STEEP
PRESSURE GRADIENT WILL PRODUCE GUSTY NORTHWEST WINDS AROUND 35
MPH.
THE 12 UTC GFS/ECMWF/SREF/GEM ARE IN GOOD AGREEMENT WITH RESPECT
TO PRECIPITATION AMOUNTS AND TEMPERATURES. THEREFORE...UTILIZED A
BLEND OF THE OPERATIONAL MODELS. THIS GENERALLY YIELDED LIQUID
PRECIPITATION AMOUNTS AROUND HALF AN INCH AND SNOW AMOUNTS AROUND
1 OR 2 INCHES SUNDAY NIGHT INTO MONDAY. WITH TEMPERATURES HOVERING
NEAR FREEZING...ROAD TEMPERATURES COULD BE WARM ENOUGH TO LIMIT
NEGATIVE IMPACTS TO TRAVEL. FROST AND TEMPERATURES IN THE 20S AND
LOW 30S ARE LIKELY SUNDAY NIGHT AND MONDAY NIGHT.
FOR NORTH DAKOTA THE REST OF THE LONG TERM APPEARS COOL AND
DRY...WITH FREQUENT RAIN CHANCES ACROSS SOUTH DAKOTA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1044 PM CDT SAT MAY 16 2015
MVFR AND IFR CONDITIONS IN RAIN THROUGH MUCH OF THE TAF PERIOD.
WINDS WILL TURN FROM THE SOUTHEAST TO THE NORTH.
&&
.HYDROLOGY...
ISSUED AT 340 PM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND TWO INCHES. CONFIDENCE IS LOW REGARDING TIMING AND
PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING
EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN
AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...WAA
LONG TERM...AJ
AVIATION...CK
HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1000 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1000 PM CDT SAT MAY 16 2015
FORECAST CHALLENGE FOR REMAINDER OF THE NIGHT WILL BE TRENDS ON
DECREASING SHOWERS AND ISOLATED TSTMS AS THE FIRST WAVE OF PRECIP
IN THE WEST MOVES INTO SOUTHERN CANADA AND SHOWERS IN THE EAST
MOVE INTO NE MINNESOTA. THE HRRR HAS BEEN USEFUL FOR 3 TO 6 HOURS
OUT TONIGHT...AND WILL CONTINUE USING ITS POP TRENDS FOR GUIDANCE.
THERE IS A PRECIP FREE AREA MAINLY ACROSS WITHIN THE RED RIVER
VALLEY AND ADJACENT COUNTIES...WITH MOST PRECIP OVER DVL BASIN AND
FORESTED AREAS OF MN. WILL SEE A GRADUAL DISSIPATION OVERNIGHT
WITH ANOTHER WAVE OF PRECIP FORMING OVER CNTRL PLAINS NEAR MORNING
AND SPREADING NORTHWARD BY MID MORNING AND THROUGHOUT THE
AFTERNOON. WILL KEEP SCT SHOWERS/ISOLD TSTMS OVERNIGHT TONIGHT
ACROSS THE REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 320 PM CDT SAT MAY 16 2015
FORECAST CHALLENGE FOR TONIGHT IS SEVERE POTENTIAL. CLOUDS HAVE
PLAYED INTO THIS A BIT FOR OUR FA TODAY...PROBABLY MOST FOR THE
NORTHERN HALF OF THE AREA. AS OF 20Z THE BROAD SFC LOW WAS LOCATED
SOMEWHERE OVER WESTERN SD. THE WARM FRONT EXTENDED OUT TO THE EAST
INTO NORTHEAST SD AND SOUTHERN MN. SEEING SOUTH WINDS BEHIND THE
FRONT AND MORE SOUTHEAST THEN ESE UP INTO THE SOUTHERN FA. TEMPS
BEHIND THE FRONT IN THE MID 70S WITH DEW POINTS IN THE LOWER 60S.
THIS IS GIVING SFC BASED CAPE VALUES OF 1000 J/KG UP INTO SOUTH
CENTRAL ND. MUCH HIGHER VALUES OVER EAST CENTRAL SD. NOT THE
GREATEST AMOUNT OF SHEAR...BUT ALSO BETTER SOUTH OF THE FA.
RECEIVED A SWOMCD AT 210 PM DISCUSSING THE POTENTIAL FOR SEVERE
WEATHER UP INTO OUR FAR SOUTHERN FA. IF ORGANIZED CONVECTION CAN
GET GOING HERE THIS WOULD BE THE FAVORED AREA FOR A WATCH. THINK
THE BEST POTENTIAL WILL STILL BE IN THE 4-5 PM THROUGH MID EVENING
TIME FRAME DOWN IN THIS AREA. THUNDERSTORMS SHOULD DECREASE IN
INTENSITY OVERNIGHT...BUT AS THE STRONGER DYNAMICS APPROACH ON
SUNDAY THERE SHOULD COULD BE ANOTHER CHANCE OF SEVERE WEATHER.
THIS TIME ACROSS THE SOUTHEAST FA AS THE LOW LEVEL AND UPPER JET
PUNCH INTO THIS AREA AHEAD OF THE SHORT WAVE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 PM CDT SAT MAY 16 2015
TEMPS FALL AND WINDS CRANK UP ACROSS THE NORTHWEST FA SUNDAY
NIGHT. COULD BE A LITTLE LIGHT SNOW ACROSS THIS AREA...CURRENTLY
SHOWING THE POTENTIAL FOR 1-3 INCHES FROM LANGDON TO KDVL. STILL
WINDY INTO MONDAY WITH SOME LINGERING LIGHT SNOW ACROSS PORTIONS
OF THE NORTHERN FA. FINALLY SEE PCPN MOVING EAST MON NIGHT INTO
TUE.
BEYOND...FOR THE LATER HALF OF THE WEEK INTO THE FIRST PART OF
THE WEEKEND HIGH PRESSURE DOES SITUATE ITSELF ALONG THE NORTH
DAKOTA/MANITOBA AND SASKATCHEWAN BORDERS. THIS WILL BRING SOME
WELCOME DRY WEATHER TO OUR AREA MID TO LATE WEEK. THERE IS A
SYSTEM MOVING INTO THE WEST COAST AND INTO THE CENTRAL PLAINS FRI-
SAT AND THE NORTHERN EDGE OF MOISTURE FROM THIS SYSTEM MAY BRUSH
SOUTHERN ND AND WEST CENTRAL MINNESOTA. 00Z ECMWF WAS MORE
AGGRESSIVE WITH PRECIP THAN ITS 12Z RUN. 12Z ECMWF RUN FOLLOWS
DRIER 00Z AND 12Z GFS RUNS. BUT KEPT IDEA OF LOW POPS IN THE
SOUTHERN FCST AREA DUE TO UNCERTAINTY WITH NORTHERN EDGE OF
MOISTURE. TEMPERATURES WARMING A BIT BACK CLOSER TO NORMAL VALUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 655 PM CDT SAT MAY 16 2015
BEST CHANCE FOR SHRA/TSRA IN NEXT SIX HOURS WILL BE BJI/TVF/DVL
WITH VALLEY DRY. SHOWERS OVER SW AND W CNTRL MN WILL LIFT INTO NW
MN EAST OF THE RED RIVER VALLEY WHILE ANOTHER CLUSTER OF STORMS
OVER CNTRL ND WILL MOVE INTO DVL AREA. MORE ACTIVITY MAY LIFT UP
TONIGHT FROM SD BUT NOT ENOUGH CONFIDENCE FOR MENTION ON STATION
AT GFK AND FAR. BEST CHANCE FOR NEXT WAVE OF PRECIP APPEARS TO BE
MID MORNING SUNDAY...EXPANDING ACROSS ENTIRE REGION IN THE AFTN.
MVFR AND VFR CIGS EXPECTED THROUGHOUT TAF PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...GODON
LONG TERM...GODON/RIDDLE
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
110 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 954 AM CDT FRI MAY 15 2015
HIGH PRESSURE NOSING INTO NORTHEAST NORTH DAKOTA ALONG WITH A
DRIER AIRMASS (CLEAR SKY). THE MAIN CHALLENGE FOR TODAY WILL BE
THE DEGREE OF CLEARING AND THIS AFFECT ON MAX TEMPS. HIGH PRESSURE
CONTINUE TO BUILD INTO THE REGION TODAY...ALTHOUGH WITH HIGHER
BASED CLOUDS ADVECTING INTO THE REGION FROM THE SOUTH...AREAS
ACROSS SOUTHEAST ND AND WC MN MAY NEVER TOTALLY BECOME CLEAR. WITH
THE CURRENT CLEAR SKY ACROSS THE NE ND DID RAISE MAX TEMPS A
COUPLE DEGREES HERE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
MODELS IN GOOD AGREEMENT FOR TODAY WITH SFC HIGH PRESSURE TO THE
NW BRINGING A TIGHTENING OF THE SFC PRESSURE GRADIENT. THIS IS
ALLOWING DRIER AIR AND CLEARING SKIES TO WORK INTO THE DEVILS LAKE
BASIN. AHEAD OF THE THIS FEATURE IS A SATURATED AIRMASS WITH
AREAS OF FOG AND SOME PATCHY DRIZZLE OCCURRING AS DEWPOINTS ARE IN
THE UPR 40S. WILL KEEP THE DRIZZLE FOG MENTION THRU 9AM.
AS THE MORNING TURNS INTO MID DAY UNCERTAINTY EXISTS IN THE
SOUTHWARD EXTENT OF THE CLEARING AND CLOUD COVER. RECENT THE RAP
AND HRRR MESOSCALE MODEL RUNS BRING THE CLEARING TO GFK BUT NOT
AS FAR SOUTH AS FARGO.
TONIGHT ATTENTION TURNS TO STRONG MOISTURE AND WARM AIR ADVECTION
ESCORTED NORTHWARD BY 30 TO 40 KT 850MB SOUTHERLY JET WHICH WILL
CONTINUE THROUGH THE DAY SATURDAY. AMOUNT OF CLOUD COVER WILL
DETERMINE SFC TEMPS AND AMOUNT OF INSTABILITY THAT DEVELOPS AHEAD
OF A DEVELOPING SFC LOW ACROSS THE WESTERN DAKOTAS. MODEL TRENDS
ARE SLOWER WITH THE SYSTEM BRINGING THE SFC LOW TO THE TRI STATE
CORNER ABOUT 12 LATER THAN PREVIOUSLY FORECAST. THAT SAID THERE
REMAINS A SLIGHT RISK FOR SEVERE STORMS ACROSS MUCH OF THE AREA ON
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
SATURDAY NIGHT INTO SUNDAY NIGHT...THE STACKED SYSTEM WRAPS MOISTURE
BACK ACROSS MUCH OF THE CWFA. WITH CATEGORICAL POPS FOR THE ENTIRE
FA SUNDAY WITH DEFORMATION BAND OF RAIN. NORTH WINDS WILL
INCREASE INTO THE 20 TO 30 KT RANGE SUNDAY ACROSS THE WEST AND
SLOWLY WORK TO THE EAST DURING THE DAY. AHEAD OF THE SFC LOW AND
WIND SHIFT THERE REMAINS A CHANCE FOR THUNDER WITH NEGATIVE
SHOWALTERS THROUGH EARLY AFTERNOON. AS THE SYSTEM SLOWING PUSHES
EAST 925MB TEMPS ACROSS THE DVL BSN AND N RRV DO DROP WELL BELOW
0C AND MODELS CONTINUE TO HINT AND THE POSSIBILITY OF SOME SNOW
FLAKES MIXED IN WITH THE BACKEND OF THE PCPN SHIELD. TOTAL
RAINFALL AMOUNTS ARE EXPECTED TO BE A WIDESPREAD 1 TO 2 INCHES
THROUGH SUNDAY NIGHT.
MONDAY TO THURSDAY...LONG WAVE RIDGE OVER THE WESTERN CANADA MOVES
LITTLE THROUGH THE PERIOD. LONG WAVE TROUGH OVER NORTHEAST CANADA
SHIFTS EAST INTO EASTERN CANADA. REX BLOCK WAS OVER WESTERN NORTH
AMERICA. COLD FRONT FORECAST TO MOVE THROUGH EARLY IN THE PERIOD.
A SURFACE RIDGE MOVES INTO THE AREA TUE NIGHT. GFS WAS A LITTLE
FASTER THAN THE ECMWF. WILL PREFER THE ECMWF.
HIGH TEMPS WERE LOWERED FOR MON AND TUE BY ONE TO FOURS DEGREES.
LITTLE CHANGE ON WED AND THU WAS INCREASED ONE OR TWO DEGREES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 110 PM CDT FRI MAY 15 2015
IFR/MVFR CLOUD DECK ALG AND SOUTH OF A BDE- VWU- FAR- JMS LINE
WILL SLOWLY SHIFT SOUTHEASTWARD THIS AFTERNOON WITH GENLY FAIR
SKIES BEHIND THE SURFACE COOL FRONT IN NORTHEASTERN ND AND FAR
NWRN MN. EXPECT CLEARING SKIES INTO SOUTHERN RRV BRIEFLY THIS
EARLY EVENING BEFORE INCLREASING MID AND LOW LEVEL MOISTURE MOVES
INTO THE FA AHEAD OF NEXT SYSTEM. OVERNIGHT...MID LVL CLOUDS
SHOULD OVERSPREAD AREA FROM THE SOUTHWEST WITH APPROACHING WARM
FRONTAL BOUNDARY. EXPECT VFR CIGS WITH SCT MVFR CIGS AND VSBYS IN
SHOWERS AND THUNDERSTORMS THROUGH THE DAY ON SATURDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...JK
LONG TERM...HOPPES/JK
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
954 AM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 954 AM CDT FRI MAY 15 2015
HIGH PRESSURE NOSING INTO NORTHEAST NORTH DAKOTA ALONG WITH A
DRIER AIRMASS (CLEAR SKY). THE MAIN CHALLENGE FOR TODAY WILL BE
THE DEGREE OF CLEARING AND THIS AFFECT ON MAX TEMPS. HIGH PRESSURE
CONTINUE TO BUILD INTO THE REGION TODAY...ALTHOUGH WITH HIGHER
BASED CLOUDS ADVECTING INTO THE REGION FROM THE SOUTH...AREAS
ACROSS SOUTHEAST ND AND WC MN MAY NEVER TOTALLY BECOME CLEAR. WITH
THE CURRENT CLEAR SKY ACROSS THE NE ND DID RAISE MAX TEMPS A
COUPLE DEGREES HERE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
MODELS IN GOOD AGREEMENT FOR TODAY WITH SFC HIGH PRESSURE TO THE
NW BRINGING A TIGHTENING OF THE SFC PRESSURE GRADIENT. THIS IS
ALLOWING DRIER AIR AND CLEARING SKIES TO WORK INTO THE DEVILS LAKE
BASIN. AHEAD OF THE THIS FEATURE IS A SATURATED AIRMASS WITH
AREAS OF FOG AND SOME PATCHY DRIZZLE OCCURRING AS DEWPOINTS ARE IN
THE UPR 40S. WILL KEEP THE DRIZZLE FOG MENTION THRU 9AM.
AS THE MORNING TURNS INTO MID DAY UNCERTAINTY EXISTS IN THE
SOUTHWARD EXTENT OF THE CLEARING AND CLOUD COVER. RECENT THE RAP
AND HRRR MESOSCALE MODEL RUNS BRING THE CLEARING TO GFK BUT NOT
AS FAR SOUTH AS FARGO.
TONIGHT ATTENTION TURNS TO STRONG MOISTURE AND WARM AIR ADVECTION
ESCORTED NORTHWARD BY 30 TO 40 KT 850MB SOUTHERLY JET WHICH WILL
CONTINUE THROUGH THE DAY SATURDAY. AMOUNT OF CLOUD COVER WILL
DETERMINE SFC TEMPS AND AMOUNT OF INSTABILITY THAT DEVELOPS AHEAD
OF A DEVELOPING SFC LOW ACROSS THE WESTERN DAKOTAS. MODEL TRENDS
ARE SLOWER WITH THE SYSTEM BRINGING THE SFC LOW TO THE TRI STATE
CORNER ABOUT 12 LATER THAN PREVIOUSLY FORECAST. THAT SAID THERE
REMAINS A SLIGHT RISK FOR SEVERE STORMS ACROSS MUCH OF THE AREA ON
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 349 AM CDT FRI MAY 15 2015
SATURDAY NIGHT INTO SUNDAY NIGHT...THE STACKED SYSTEM WRAPS MOISTURE
BACK ACROSS MUCH OF THE CWFA. WITH CATEGORICAL POPS FOR THE ENTIRE
FA SUNDAY WITH DEFORMATION BAND OF RAIN. NORTH WINDS WILL
INCREASE INTO THE 20 TO 30 KT RANGE SUNDAY ACROSS THE WEST AND
SLOWLY WORK TO THE EAST DURING THE DAY. AHEAD OF THE SFC LOW AND
WIND SHIFT THERE REMAINS A CHANCE FOR THUNDER WITH NEGATIVE
SHOWALTERS THROUGH EARLY AFTERNOON. AS THE SYSTEM SLOWING PUSHES
EAST 925MB TEMPS ACROSS THE DVL BSN AND N RRV DO DROP WELL BELOW
0C AND MODELS CONTINUE TO HINT AND THE POSSIBILITY OF SOME SNOW
FLAKES MIXED IN WITH THE BACKEND OF THE PCPN SHIELD. TOTAL
RAINFALL AMOUNTS ARE EXPECTED TO BE A WIDESPREAD 1 TO 2 INCHES
THROUGH SUNDAY NIGHT.
MONDAY TO THURSDAY...LONG WAVE RIDGE OVER THE WESTERN CANADA MOVES
LITTLE THROUGH THE PERIOD. LONG WAVE TROUGH OVER NORTHEAST CANADA
SHIFTS EAST INTO EASTERN CANADA. REX BLOCK WAS OVER WESTERN NORTH
AMERICA. COLD FRONT FORECAST TO MOVE THROUGH EARLY IN THE PERIOD.
A SURFACE RIDGE MOVES INTO THE AREA TUE NIGHT. GFS WAS A LITTLE
FASTER THAN THE ECMWF. WILL PREFER THE ECMWF.
HIGH TEMPS WERE LOWERED FOR MON AND TUE BY ONE TO FOURS DEGREES.
LITTLE CHANGE ON WED AND THU WAS INCREASED ONE OR TWO DEGREES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 638 AM CDT FRI MAY 15 2015
IFR CIGS AS MOST SITES WITH CIGS EXPECTED TO SLOWLY RISE TO MVFR
TODAY AND INTO VFR THIS AFTN. SOME FG AND BR THIS MORNING SHOULD
MIX OUT IN THE NEXT FEW HOURS. RAIN OR THUNDER POSSIBLE OVERNIGHT
THOUGH TIMING AND LOCATION REMAIN UNCERTAIN ENOUGH TO LEAVE OUT OF
TAFS FOR NOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...JK
LONG TERM...HOPPES/JK
AVIATION...JK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
806 PM EDT SAT MAY 16 2015
.SYNOPSIS...
WEAK MID/UPPER LEVEL DISTURBANCES...INCREASED MOISTURE AND INSTABILITY
RESULTS IN ROUNDS OF SHOWERS/THUNDERSTORMS INTO EARLY NEXT WEEK. COLD
FRONT PUSHES EAST TUESDAY. DRIER WEDNESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
730 PM UPDATE...NO CHANGES MADE TO CURRENT FORECAST. WITH LOSS OF
DAYTIME HEATING ANY THUNDER SHOULD BECOME LESS. WILL STILL LEAVE
THUNDERSTORM CHANCES IN THE GRIDS BASED ON THE INSTABILITY.
EXPECTING THE MAJORITY OF THE SHOWERS WILL DIE OFF DIURNALLY
LEAVING ONLY THE SHOWERS AND A RUMBLE OF THUNDER OR TWO ASSOCIATED
WITH ANY VORT MAXES THAT GET UNDER THE BROAD RIDGE.
PREVIOUS DISCUSSION...
STILL HIGHLIGHTING THE RAIN...OVER ANY CONVECTIVE SEVERE THREAT
FOR LARGE HAIL AND DAMAGING WINDS.
THINKING WE COULD HAVE SOME EFFICIENT RAIN MAKERS/DUMPERS NEXT 24
HOURS...AS PRECIPITABLE WATER INCREASES TOWARD 1.7 INCHES.
PLUS...WE HAVE WEAK MID/UPPER LEVEL DISTURBANCES TRYING TO RIDE UP
AND OVER THE STUBBORN SE 500 MB RIDGE.
OF COURSE...MOST COUNTIES NEED THE RAIN. PLUS...WE HAVE OUR BIG
CONSUMER NOW WORKING HARD...THAT BEING THE FRESH SPRING VEGETATION.
YET...WE DO NOT WANT TOO MUCH OF A GOOD THING. JUST MENTIONED IN THE
HAZARDOUS WEATHER POTENTIAL ABOUT SOME PROGRESSIVE LOCALIZED
DOWNPOURS. WE JUST HAVE TO WATCH FOR ANY REPETITIVE ACTION.
THAT BEING SAID...THE VORT MAX WE DISCUSSED IN THE MORNING UPDATED
AFD...LIFTED THROUGH NORTH CENTRAL WV ON SCHEDULE AROUND 17Z. A FEW
SPOTS GOT A HALF INCH OF RAIN...MOST GOT MUCH LESS. MOST OF THAT
ENERGY AT 1830Z WAS TRANSFERRING EAST OF US...TOWARD SOUTH CENTRAL
PENNSYLVANIA AND FAR EASTERN WV PANHANDLE.
NEXT VORT MAX ON RAP MOVES OUT OF KENTUCKY AND TOWARD MID OHIO
VALLEY AND PKB BY 01Z SUNDAY. SO MENTIONED SOME LOCALIZED DOWNPOURS
ASSOCIATED WITH IT...ACROSS OUR WESTERN COUNTIES.
MOST MODEL SOLUTIONS SHOW ANOTHER 500 MB DISTURBANCE LATE TONIGHT
FROM 06Z TO 12Z SUNDAY...RIDGING THROUGH SE OHIO THEN ACROSS
NORTHERN WV SUNDAY MORNING. SO OF COURSE...HAD TO LEAVE POPS
THROUGH THE NIGHT...HIGHEST IN THE WEST AND NORTH...LOWEST IN THE
SOUTH AND EAST.
NO BIG CHANGES PICTURED FOR SUNDAY...THROUGH THE HIGHER POPS MAY
TRANSFER TO THE MOUNTAINS SUNDAY AFTERNOON...BEFORE TRANSFERRING
BACK WEST AGAIN.
FIGURING MAXIMUM TEMPERATURES REMAIN A HEADACHE...JUST DEPENDING ON
THE BREAKS IN THE CLOUDS AND TIMING OF THE SHOWERS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS NOTED BY PREVIOUS SHIFT...MODELS HAVE SLOWED DOWN COLD FRONT
PASSAGE UNTIL TUESDAY. MAIN CHANGES THIS FORECAST PACKAGE WERE TO
INCREASE POPS SOME ON TUESDAY AND ALSO TRY TO A THIN LINE OF HIGHER
POPS ALONG THE FRONT AS IT MOVES THROUGH ON TUESDAY. HAVE THE
HIGHEST POPS ACROSS THE EAST...AS THE FRONT WILL BE CROSSING THERE
DURING THE AFTERNOON. WITH THE DELAYED FROPA...ALSO RAISED
TEMPERATURES A BIT MONDAY NIGHT AND TUESDAY. OUTSIDE OF THESE
CHANGES...MAINTAINED LIKELY POPS ON MONDAY IN THE WARM SECTOR.
PRECIPITABLE WATER VALUES ON MONDAY WILL BE AROUND 1.75 INCHES. THIS
WILL LIKELY PRODUCE POCKETS OF HEAVY RAIN IN AREAS OF HEALTHY
CONVECTION. STORMS SHOULD MAINLY BE SCATTERED IN NATURE...WITH
LITTLE SYNOPTIC ORGANIZATIONAL FORCING...SO WILL JUST HAVE TO WATCH
FOR AREAS THAT MAY RECEIVE REPETITIVE BURSTS AS THE DAY GOES ON.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
NO REAL SIGNIFICANT WEATHER MAKERS IN THE LONG TERM PATTERN. THE
PERIOD WILL START OUT ON THE NEAR NORMAL TO COOL SIDE IN THE WAKE OF
TUESDAYS COLD FRONT. GFS/ECMWF BOTH SHOW A SURFACE HIGH SLOWLY
MARCHING ACROSS THE NORTHERN PLAINS FOR THE LATTER HALF OF THE WEEK
INTO THE WEEKEND. ANY PRECIPITATION SHOULD BE TIED TO 500MB RIPPLES
WORKING THROUGH THE FAIRLY ZONAL FLOW. HAVE SOME SLIGHT CHANCE POPS
ACROSS THE HIGHER TERRAIN THURSDAY AND FRIDAY AFTERNOON...BUT
CONFIDENCE ON THIS IS RATHER LOW AT THIS POINT. TEMPERATURES WILL BE
BACK UP TO NEAR AND ABOVE NORMAL BY THE END OF THE WEEK.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
HIGHLY VARIABLE CONDITIONS IN ROUNDS OF SHOWERS AND THUNDERSTORMS.
FOR THE OVERNIGHT HOURS THINKING THE BEST CHANCE FOR SHOWERS WILL
BE FOR THE NORTHERN HALF OF THE FORECAST AREA AND MOVE ACROSS
KHTS...KCRW...KPKB...AND POSSIBLE KEKN. DON/T REALLY EXPECT
THUNDER AND TIMING THESE WILL BE DIFFICULT SO WILL USE VCSH.
OUTSIDE OF THE CONVECTION...HAVE VSBY BECOMING 3 TO 5 MILES IN
LIGHT FOG 06Z TO 12Z. HOPING LAYERED CLOUDS AND BOUNDARY LAYER
WINDS KEEP THREAT FOG OUTSIDE OF THE CONVECTION FROM FORMING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY...
FORECAST CONFIDENCE: MEDIUM
ALTERNATE SCENARIOS: HIGHLY VARIABLE CONDITIONS IN THE SHOWERS AND
STORMS WITH CONDITIONS BRIEFLY GOING LOWER THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SUN 05/17/15
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY M M M M M M M M M M H H
HTS CONSISTENCY M M M M M M H H H H H H
BKW CONSISTENCY M M M M M H H H H H H H
EKN CONSISTENCY M M M M M M H H H H M H
PKB CONSISTENCY M M M M M M H M M M M H
CKB CONSISTENCY M M M M M M M M M M M M
AFTER 00Z MONDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY AFTERNOON
INTO TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...MZ
AVIATION...FB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
746 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A DEVELOPING WARM FRONT OVER THE OHIO VALLEY WILL INITIATE SOME
SHOWERS AND A FEW THUNDERSTORMS TODAY AS IT MOVES NORTHEAST ACROSS
THE AREA. A WARMER AND MORE HUMID AIRMASS WILL BE IN PLACE FOR THE
WEEKEND WHEN HIGH PRESSURE TO OUR EAST RESULTS IN SOUTHERLY FLOW.
A COLD FRONT WILL MOVE ACROSS THE AREA ON MONDAY AND BRING COOLER
TEMPERATURES FOR MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS ASSOCIATED WITH WARM ADVECTION HAVE NOW REACHED INTO
NORTHWEST OHIO. AS AN UPPER LEVEL SHORTWAVE CROSSES THE REGION
EXPECT THESE SHOWERS TO WORK THEIR WAY ACROSS NRN OH AND INTO NW
PA BY MID AFTERNOON. SOME RUMBLES OF THUNDER ARE ALSO POSSIBLE
THIS MORNING...NOT MUCH IN THE WAY OF ELEVATED INSTABILITY.
LATEST HRRR RUNS HAVE A GOOD HANDLE ON THE CURRENT SITUATION AND
HAVE USED THAT AS A GUIDE FOR THIS CURRENT BATCH OF SHOWERS.
ATTEMPTED TO MOVE THE BETTER CHANCES ACROSS THE AREA DURING THE
MORNING AND EARLY AFTERNOON. LATER TODAY NW OHIO WILL BE ABLE TO
RECOVER AND GET SOMEWHAT UNSTABLE. THE UPPER SUPPORT WILL BE
LACKING AND THEREFORE ANY CONVECTION THAT CAN POP UP ALONG A
RECOVERING INSTABILITY AXIS WOULD NOT BE ORGANIZED AND NOT COVER A
LOT OF GROUND. INCREASED PRECIP CHANCES TOWARD TOLEDO BEFORE
EVENING IF ADDITIONAL CONVECTION CAN DEVELOP...AND LINGERED POPS
ELSEWHERE. TEMPERATURES TODAY WILL BE MUCH MILDER....SOLIDLY IN
THE 70S...WITH SPOTS WEST OF CLEVELAND GETTING CLOSE TO 80. EARLY
MORNING UPDATE INCLUDED TWEAKS TO HOURLY TEMPERATURES AND TO
INCREASE PRECIP CHANCE FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
A RATHER WARM AND SOMEWHAT HUMID PERIOD IS EXPECTED WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE SHORT TERM.
THE BIG QUESTION OF WHETHER IT WILL RAIN/THUNDER OVER YOUR HEAD IS
STILL HARD TO ANSWER AND UNFORTUNATELY THE FORECAST STILL REMAINS
FAIRLY GENERIC WITH PRECIP CHANCES THAT FLUCTUATE DIURNALLY. WE
WILL BE IN THE WARM SECTOR AND THERE IS NO LARGE SCALE FORCING TO
INITIATE OR MAINTAIN CONVECTION. OVERALL THE UPPER RIDGE WILL ACT
TO SUPPRESS CONVECTION. AT THE SAME TIME THOUGH MODELS SHOWING AN
INCREASE IN MOISTURE AND QPF. THE QPF IS LIKELY OVERDONE AS HAS
BEEN THE CASE LATELY. IT WILL BE SMALLER SCALE FEATURES THAT WILL
ACT TO INITIATE CONVECTION AND THEREFORE WILL HAVE TO TAKE IT ONE
DAY AT A TIME IN DETERMINING WHO HAS THE BEST CHANCES AND HOW GOOD
OF A CHANCE IT REALLY IS.
IT WILL BE WARM AND MORE HUMID. EXPECT HIGHS OVER THE WEEKEND TO
REACH OR EXCEED 80 AWAY FROM THE LAKE. DEWPOINTS WILL BE NEARING
60 AND NIGHT LOWS WILL BE MILD.
THE COLD FRONT IS EXPECTED TO CROSS MONDAY. HAVE CONTINUED WITH THE
60 PERCENT OR GREATER PRECIP CHANCES WITH THIS SIGNIFICANT
FEATURE...BUT TIMING STILL UNCERTAIN AS IS HOW MUCH ACTIVITY THERE
WILL BE LEADING UP TO IT SUNDAY NIGHT. THE COLD FRONT ITSELF
CROSSES MONDAY EVENING. THERE STILL REMAINS DIFFERENCES ON HOW
MUCH COOL AIR IT BRINGS IN ITS WAKE.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STARTING 12Z TUESDAY A COLD FRONT WILL BE EAST OF THE AREA. HIGH
PRESSURE WILL QUICKLY FILL IN BEHIND THE FRONT...SETTING THE STAGE
FOR STRONG RADIATIONAL COOLING TUESDAY NIGHT. TEMPERATURES WILL FALL
BACK INTO THE LOW 40`S ACROSS THE REGION UNDER A MOSTLY CLEAR SKY.
TUESDAY`S HIGHS WILL STRUGGLE TO GET MUCH ABOVE 60.
BY TUESDAY THE PATTERN BECOMES DE-AMPLIFIED AS AN UPPER LEVEL LOW
SHUFFLES EAST. A BROAD AREA OF HIGH PRESSURE WILL BECOME ESTABLISHED
OVER THE MIDSECTION OF THE COUNTRY AND SPREAD EAST THROUGH THE
REMAINDER OF THE EXTENDED FORECAST. THE WEATHER WILL BE PLEASANT AND
SEASONABLE.
REMOVED SLIGHT CHANCE POPS FROM THE FORECAST ON THURSDAY
AFTERNOON. SHOULD SEE MORE IN THE WAY OF CLOUDS THAN RAIN IN LIGHT
OF ZONAL FLOW ALOFT AND LARGE SURFACE HIGH.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHOWERS ARE NOW MOVING THROUGH OHIO THIS MORNING. THESE SHOWERS
WILL BRIEFLY DROP VISIBILITY TO MVFR. AN ISOLATED RUMBLE OF
THUNDER IS ALSO POSSIBLE WITH THESE SHOWERS. AFTER THE RAIN CLEARS
ERIE BY LATE MORNING FRIDAY...SKIES WILL BECOME MOSTLY OVERCAST
AND THE WIND WILL BEGIN TO PICK UP OUT THE SOUTH. WESTERNMOST
SITES HAVE THE POTENTIAL TO GUST UP TO 25 KNOTS BY THIS
AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP
LATER IN THE AFTERNOON AND LAST INTO THE EVENING. OVERNIGHT MVFR
FOG WILL DEVELOP AT MANY TERMINALS AS DEW POINTS CLIMB INTO
THE 60/S AND THE WIND DECREASES TO AROUND 5 KNOTS.
.OUTLOOK...NON VFR AT TIMES IN SCATTERED SHOWERS OR THUNDERSTORMS
THRU MON EVENING.
&&
.MARINE...
A WARM FRONT WILL LIFT NORTH ACROSS LAKE ERIE EARLY FRIDAY
AFTERNOON. WAVES WILL GENERALLY BE 3 FEET OF LESS ON THE OPEN WATERS
THROUGH THE WEEKEND WITH SOUTH TO SOUTHWEST FLOW OF 15 KNOTS OR
LESS.
MONDAY NIGHT A COLD FRONT WILL CROSS THE LAKE AND WAVES WILL BUILD
TO 2 TO 4 FEET ON THE OPEN LAKE. BY TUESDAY MORNING THE WIND WILL BE
FROM THE NORTHWEST AT 10 TO 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...MAYERS
AVIATION...MAYERS
MARINE...MAYERS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
627 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A DEVELOPING WARM FRONT OVER THE OHIO VALLEY WILL INITIATE SOME
SHOWERS AND A FEW THUNDERSTORMS TODAY AS IT MOVES NORTHEAST ACROSS
THE AREA. A WARMER AND MORE HUMID AIRMASS WILL BE IN PLACE FOR THE
WEEKEND WHEN HIGH PRESSURE TO OUR EAST RESULTS IN SOUTHERLY FLOW.
A COLD FRONT WILL MOVE ACROSS THE AREA ON MONDAY AND BRING COOLER
TEMPERATURES FOR MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS ASSOCIATED WITH WARM ADVECTION HAVE NOW REACHED INTO
NORTHWEST OHIO. AS AN UPPER LEVEL SHORTWAVE CROSSES THE REGION
EXPECT THESE SHOWERS TO WORK THEIR WAY ACROSS NRN OH AND INTO NW
PA BY MID AFTERNOON. SOME RUMBLES OF THUNDER ARE ALSO POSSIBLE
THIS MORNING...NOT MUCH IN THE WAY OF ELEVATED INSTABILITY.
LATEST HRRR RUNS HAVE A GOOD HANDLE ON THE CURRENT SITUATION AND
HAVE USED THAT AS A GUIDE FOR THIS CURRENT BATCH OF SHOWERS.
ATTEMPTED TO MOVE THE BETTER CHANCES ACROSS THE AREA DURING THE
MORNING AND EARLY AFTERNOON. LATER TODAY NW OHIO WILL BE ABLE TO
RECOVER AND GET SOMEWHAT UNSTABLE. THE UPPER SUPPORT WILL BE
LACKING AND THEREFORE ANY CONVECTION THAT CAN POP UP ALONG A
RECOVERING INSTABILITY AXIS WOULD NOT BE ORGANIZED AND NOT COVER A
LOT OF GROUND. INCREASED PRECIP CHANCES TOWARD TOLEDO BEFORE
EVENING IF ADDITIONAL CONVECTION CAN DEVELOP...AND LINGERED POPS
ELSEWHERE. TEMPERATURES TODAY WILL BE MUCH MILDER....SOLIDLY IN
THE 70S...WITH SPOTS WEST OF CLEVELAND GETTING CLOSE TO 80. EARLY
MORNING UPDATE INCLUDED TWEAKS TO HOURLY TEMPERATURES AND TO
INCREASE PRECIP CHANCE FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
A RATHER WARM AND SOMEWHAT HUMID PERIOD IS EXPECTED WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE SHORT TERM.
THE BIG QUESTION OF WHETHER IT WILL RAIN/THUNDER OVER YOUR HEAD IS
STILL HARD TO ANSWER AND UNFORTUNATELY THE FORECAST STILL REMAINS
FAIRLY GENERIC WITH PRECIP CHANCES THAT FLUCTUATE DIURNALLY. WE
WILL BE IN THE WARM SECTOR AND THERE IS NO LARGE SCALE FORCING TO
INITIATE OR MAINTAIN CONVECTION. OVERALL THE UPPER RIDGE WILL ACT
TO SUPPRESS CONVECTION. AT THE SAME TIME THOUGH MODELS SHOWING AN
INCREASE IN MOISTURE AND QPF. THE QPF IS LIKELY OVERDONE AS HAS
BEEN THE CASE LATELY. IT WILL BE SMALLER SCALE FEATURES THAT WILL
ACT TO INITIATE CONVECTION AND THEREFORE WILL HAVE TO TAKE IT ONE
DAY AT A TIME IN DETERMINING WHO HAS THE BEST CHANCES AND HOW GOOD
OF A CHANCE IT REALLY IS.
IT WILL BE WARM AND MORE HUMID. EXPECT HIGHS OVER THE WEEKEND TO
REACH OR EXCEED 80 AWAY FROM THE LAKE. DEWPOINTS WILL BE NEARING
60 AND NIGHT LOWS WILL BE MILD.
THE COLD FRONT IS EXPECTED TO CROSS MONDAY. HAVE CONTINUED WITH THE
60 PERCENT OR GREATER PRECIP CHANCES WITH THIS SIGNIFICANT
FEATURE...BUT TIMING STILL UNCERTAIN AS IS HOW MUCH ACTIVITY THERE
WILL BE LEADING UP TO IT SUNDAY NIGHT. THE COLD FRONT ITSELF
CROSSES MONDAY EVENING. THERE STILL REMAINS DIFFERENCES ON HOW
MUCH COOL AIR IT BRINGS IN ITS WAKE.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STARTING 12Z TUESDAY A COLD FRONT WILL BE EAST OF THE AREA. HIGH
PRESSURE WILL QUICKLY FILL IN BEHIND THE FRONT...SETTING THE STAGE
FOR STRONG RADIATIONAL COOLING TUESDAY NIGHT. TEMPERATURES WILL FALL
BACK INTO THE LOW 40`S ACROSS THE REGION UNDER A MOSTLY CLEAR SKY.
TUESDAY`S HIGHS WILL STRUGGLE TO GET MUCH ABOVE 60.
BY TUESDAY THE PATTERN BECOMES DE-AMPLIFIED AS AN UPPER LEVEL LOW
SHUFFLES EAST. A BROAD AREA OF HIGH PRESSURE WILL BECOME ESTABLISHED
OVER THE MIDSECTION OF THE COUNTRY AND SPREAD EAST THROUGH THE
REMAINDER OF THE EXTENDED FORECAST. THE WEATHER WILL BE PLEASANT AND
SEASONABLE.
REMOVED SLIGHT CHANCE POPS FROM THE FORECAST ON THURSDAY
AFTERNOON. SHOULD SEE MORE IN THE WAY OF CLOUDS THAN RAIN IN LIGHT
OF ZONAL FLOW ALOFT AND LARGE SURFACE HIGH.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
HIGH CLOUDS WILL CONTINUE TO THIN OVERNIGHT WHILE MID CLOUDS
THICKEN. THE PREVIOUS TAF PACKAGE REMAINS IN GOOD SHAPE AND MADE
ONLY SUBTLE CHANGES WITH THIS ISSUANCE. AN INITIAL WAVE OF MOSTLY
LIGHT RAIN SHOWERS WILL AFFECT MAINLY NORTHWEST OHIO BETWEEN 12
AND 18Z FRIDAY. MORE RECENT MODEL RUNS CONTINUE TO SUGGEST THE
RAIN WILL PETER OUT AS IT MOVES EAST. AFTER 18Z THE ENTIRE AREA
WILL LIKELY SEE SCATTERED THUNDERSHOWERS DEVELOP AHEAD OF A WARM
FRONT. THERE WILL LIKELY BE A LULL IN THE ACTIVITY AFTER 00Z
SATURDAY.
.OUTLOOK...NON VFR AT TIMES IN SHOWERS OR THUNDERSTORMS THRU MON
EVENING.
&&
.MARINE...
A WARM FRONT WILL LIFT NORTH ACROSS LAKE ERIE EARLY FRIDAY
AFTERNOON. WAVES WILL GENERALLY BE 3 FEET OF LESS ON THE OPEN WATERS
THROUGH THE WEEKEND WITH SOUTH TO SOUTHWEST FLOW OF 15 KNOTS OR
LESS.
MONDAY NIGHT A COLD FRONT WILL CROSS THE LAKE AND WAVES WILL BUILD
TO 2 TO 4 FEET ON THE OPEN LAKE. BY TUESDAY MORNING THE WIND WILL BE
FROM THE NORTHWEST AT 10 TO 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...MAYERS
AVIATION...MAYERS
MARINE...MAYERS
AREA FORECAST DISCUSSION
NWS NORMAN OK
232 PM CDT FRI MAY 15 2015
.DISCUSSION...
SEVERE STORM AND FLASH FLOODING POTENTIAL LATE TONIGHT THROUGH
EARLY SUNDAY ARE THE PRIMARY CONCERNS.
ISSUED A FLASH FLOOD WATCH FOR LOCATIONS SOUTH OF ELK CITY TO
WEATHERFORD TO KINGFISHER TO STILLWATER LINE WHERE THE HEAVIEST
RAINFALL TOTALS DURING THE PAST 10 DAYS HAVE OCCURRED AND WHERE
THE POTENTIAL FOR FLASH FLOODING SEEMS TO BE HIGHEST AS A FEW
ADDITIONAL INCHES OF RAINFALL MAY OCCUR THROUGH SUNDAY MORNING.
LOCATIONS SOUTHEAST OF I-44 SATURDAY NIGHT MAY HAVE THE HIGHEST
RAINFALL AND GREATEST POTENTIAL FOR HEAVY RAINFALL AND FLASH
FLOODING.
THROUGH MIDNIGHT TONIGHT...OVERALL THINK STORM CHANCES WILL BE
LIMITED DUE TO CAPPING. KEPT LOW CHANCES OF STORMS MAINLY OVER
WESTERN OKLAHOMA WHERE BEST HEATING FROM ABUNDANT SUNSHINE IS
CURRENTLY OCCURRING. IF STORMS FORM...THEY COULD BE MARGINALLY
SEVERE WITH HAIL AND WIND. LOWERED RAIN CHANCES DURING THIS TIME
FRAME.
FROM MIDNIGHT TONIGHT TO 7 AM SATURDAY...STORM CHANCES WILL
INCREASE...ESPECIALLY IN WESTERN OKLAHOMA AS STORMS FORMING OVER
THE TEXAS PANHANDLE MOVE EAST. THEY MAY ORGANIZE INTO A CLUSTER
OR LINE AS DEPICTED BY SOME LATEST HRRR AND WRF RUNS. SOME OF
THESE MAY BE SEVERE WITH MARGINAL SEVERE HAIL UP TO HALF DOLLARS
AND WINDS UP TO 70 MPH...THOUGH STORMS SHOULD WEAKEN AS THEY MOVE
EAST THROUGH THE NIGHT INTO A MORE STABLE AND SLIGHTLY WEAKLY
SHEARED ENVIRONMENT. DO NOT THINK SEVERE STORMS WILL BE WIDESPREAD
LATE TONIGHT. LOCALLY HEAVY RAINFALL OF 1 TO 2 INCHES MAY OCCUR
WHICH COULD CAUSE FLASH FLOODING.
BETWEEN 7 AM AND 3 PM SATURDAY...ONGOING WEAKENING STORMS WILL
LIKELY CONTINUE TO SPREAD EAST...POSSIBLY REACHING THE I-44
CORRIDOR AROUND 9 AM IN THE MORNING. THIS MAY LEAVE BEHIND A LOW
LEVEL COLD POOL...ABUNDANT CLOUD COVER...AND MORE STABLE
CONDITIONS ACROSS MUCH OF THE AREA. THE SEVERE THREAT APPEARS TO
BE RATHER LOW DURING THIS TIME FRAME. LOCALLY HEAVY DOWNPOURS MAY
PRODUCE SOME FLASH FLOODING.
BETWEEN 3 PM AND MIDNIGHT SATURDAY...SEVERE THUNDERSTORM POTENTIAL
REMAINS UNCERTAIN...ESPECIALLY AS EARLY DAY STORMS MAY COOL AND
STABILIZE THE AIR. THERE IS A CHANCE FOR THE REDEVELOPMENT OF
SEVERE STORMS NEAR AND JUST EAST OF DRYLINE IN WESTERN OKLAHOMA
AND WESTERN NORTH TEXAS...THEN QUICKLY MOVE NORTHEAST. IF THESE
STORMS REFORM...THEY WOULD LIKELY BE SUPERCELLULAR AND COULD
PRODUCE SIGNIFICANT SEVERE WEATHER WITH VERY LARGE HAIL AND
TORNADOES DUE TO VERY STRONG SHEAR. ANOTHER SCENARIO IS THE THAT
EARLY DAY STORMS LEAVE AN OUTFLOW BOUNDARY NEAR OR SOUTHEAST OF
I-44 FOR THE REDEVELOPMENT OF STORMS NEAR THIS BOUNDARY WHICH
COULD BE SEVERE WITH HAIL...WIND...AND PERHAPS TORNADOES. THIS
SECOND SCENARIO SEEMS TO HAVE LESS POTENTIAL FOR SIGNIFICANT
SEVERE STORMS. MESOSCALE DETAILS WILL HAVE A LARGE IMPACT ON
SEVERE WEATHER POTENTIAL SATURDAY AND SATURDAY NIGHT. LOCALLY
HEAVY RAINFALL BANDS COULD SETUP SOMEWHERE OVER THE AREA AND LEAD
TO FLASH FLOODING...THOUGH EXACTLY WHERE AND WHEN REMAINS VERY
UNCERTAIN.
LATE SATURDAY NIGHT...HEAVY RAINFALL AND FLASH FLOODING POTENTIAL
MAY CONTINUE...ESPECIALLY SOUTHEAST OF I-44...THOUGH SEVERE
POTENTIAL WILL LIKELY DECREASE THROUGH THE NIGHT AS THE AIR BECOME
COOLER AND MORE STABLE. KEPT HIGHEST RAIN CHANCES IN THESE
LOCATIONS.
SUNDAY AND SUNDAY NIGHT...A FEW STORMS MAY LINGER SOUTH OF A
WICHITA FALLS TO ADA LINE THAT MAY PRODUCE LOCALLY HEAVY RAINFALL
AND PERHAPS BE ON STRONG TO PERHAPS SEVERE SIDE.
OTHERWISE...WARM...HUMID...AND RAINFREE CONDITIONS ARE EXPECTED.
MONDAY THROUGH FRIDAY...RAIN CHANCES WILL REMAIN IN THE FORECAST
DURING THIS TIME FRAME...ESPECIALLY TUESDAY NIGHT INTO WEDNESDAY.
ADDITIONAL HEAVY RAINFALL...FLOODING...AND SEVERE STORMS MAY BE
POSSIBLE. TEMPERATURES ARE FORECAST TO BE SLIGHTLY BELOW AVERAGE.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 66 77 62 83 / 20 60 50 10
HOBART OK 62 79 56 81 / 50 70 40 10
WICHITA FALLS TX 66 79 61 83 / 30 70 50 10
GAGE OK 60 81 54 82 / 70 60 30 10
PONCA CITY OK 67 78 61 81 / 20 60 50 10
DURANT OK 68 80 63 80 / 20 50 80 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SUNDAY MORNING
FOR OKZ016>048-050>052.
TX...FLASH FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SUNDAY MORNING
FOR TXZ083>090.
&&
$$
26/17
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1217 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST FROM THE OHIO VALLEY AND INTO
THE REGION LATER THIS AFTERNOON AND TONIGHT...BRINGING
CONSIDERABLE CLOUDINESS THROUGHOUT THE DAY AND A CHANCE OF SHOWERS
BY LATER THIS AFTERNOON. THE FRONT WILL STALL OVER THE REGION THIS
WEEKEND...BRINGING VARIABLE CLOUDS AND A CHANCE OF SHOWERS EACH
AFTERNOON. A COLD FRONT WILL MOVE ACROSS THE AREA MONDAY NIGHT AND
TUESDAY...USHERING IN A COOL AIRMASS FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
HIGH PRESSURE DRIFTING OFF OF THE MID ATLANTIC COAST ATTM. IN ITS
WAKE...A FAIRLY VIGOROUS BUT MOISTURE STARVED UPPER SHORTWAVE
WILL BE MOVING EAST FROM THE LWR GLAKES REGION THE AFTERNOON...AND
OUT-RUNNING THE SFC WARM FRONT.
A SLOWLY ERODING AREA OF LGT-MDT RAIN SHOWERS ACROSS NRN OHIO AND
FAR NWRN PENN AT 16Z IS PROGGED BY THE HRRR TO MOVE ESE AND BREAK
UP EVEN MORE - TO SCATTERED SHRA AND A FEW ISOLATED TSRA ACROSS
THE NW HALF OF THE STATE BY 23Z.
ACROSS THE SE HALF OF THE CWA...EXPECT A 5-15 KT SOUTH TO SSW
BREEZE THIS AFTERNOON WITH SUNSHINE FILTERED THROUGH AREAS OF
CIRRUS AND HIGH ALTO CU. JUST A FEW ISOLATED SHRA/TSRA ARE
POSSIBLE AFTER 20Z ACROSS SCENT/SERN PENN.
BEST OVERALL CHC OF RAIN /70-80 PERCENT/ THIS AFTERNOON APPEARS
TO BE OVR THE NW MTNS...CLOSEST TO TRACK OF THE AFOREMENTIONED
SHORTWAVE. LOWEST POPS OF ONLY ARND 15 PCT FOR A LATE DAY SHRA
WILL CONTINUE TO BE ACROSS THE SE COUNTIES...WHERE AIR MASS WILL
REMAIN RELATIVELY STABLE/DRIER EAST OF WARM FRONT WITH SFC
DEWPOINTS IN THE U40S TO AROUND 50F.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WARM FRONT GETS HUNG UP ACROSS N CENTRAL TONIGHT AS FLAT RIDGE
CONTINUES TO BE IMPACTED BY EMBEDDED SHORTWAVE TROFS. THIS WILL
KEEP CHC OF SHOWERS GOING...ALTHOUGH MUCH OF THE TIME WILL BE RAIN
FREE IN MOST AREAS. BEST CHC FOR SHOWERS WILL COME SATURDAY
AFTERNOON OVER THE WESTERN AND NORTHERN HIGH TERRAIN AS CAPES GROW
TO SEVERAL HUNDRED J/KG AND BOUNDARY PROVIDES A FOCUS/TRIGGER FOR
INITIATION. MINS TONIGHT WILL BE MILD...GENERALLY RANGING FROM THE
UPPER 50S NORTH THROUGH THE 60S SOUTH. HIGHS ON SATURDAY WILL
RANGE FROM THE MID 70S NORTH TO AROUND 80 SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE SURFACE LOW REACHING THE UPPER MIDWEST BY EARLY FRIDAY WILL BE
PRECEDED BY A WARM FRONT AS IT CROSSES THE GREAT LAKES/OH VALLEY
AND REACHES THE MID ATLANTIC AND NORTHEAST STATES BY THIS
WEEKEND. A SUFFICIENT INCREASE IN MOISTURE (PWS) AND INSTABILITY
WILL SUPPORT SCATTERED CONVECTION INTO EARLY NEXT WEEK WITH THE
WARM FRONT AND ALSO WITH A TRAILING SURFACE TROUGH EXTENDING
TOWARD THE NORTHERN APPALACHIANS PROVIDING SOME ADDITIONAL LIFT.
A WELL-DEFINED COLD FRONT SHOULD CROSS THE REGION LATER MONDAY
INTO EARLY TUESDAY WITH THE GREATEST RISK FOR WIDESPREAD SHOWERS
AND T-STORMS. THE PARENT SHORTWAVE TROUGH WILL SUPPRESS THE ERN
RIDGE AND ALLOW COOLER/DRIER AIR TO ARRIVE BY MIDWEEK...AS HIGH
PRESSURE SETTLES SEWD FROM THE UPPER PLAINS INTO THE MID ATLC.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
VARIABLE AMOUNTS/THICKNESS OF MID AND HIGH CLOUDS WILL OCCUR
TODAY ACROSS MUCH OF CENTRAL AND SERN PENN...AHEAD OF A WARM FRONT
LIFTING NE FROM THE OHIO RIVER VALLEY. ACROSS OUR NW/NCENT MTN
ZONES...CLOUDS WILL LOWER AND THICKEN TODAY...THOUGH THE MAINLY
MID CLOUD DECK SHOULD REMAIN IN THE VFR RANGE THROUGH MOST OF THE
DAY.
LATEST HI RESOLUTION MODEL RUNS BRING IN THE SHOWERS THROUGH NWRN
PA BEGINNING AROUND 18Z /APPROX 19Z AT KBFD/ AND MOVING EASTWARD
THROUGH 00Z /IMPACTING TAF SITES MAINLY ALONG AND NORTH OF A KDUJ
TO KIPT LINE...OR NORTH OF INTERSTATE 80/.
MVFR TO IFR POSSIBLE IN ANY OF THE SHOWERS AND THUNDERSTORMS. THE
CHANCES FOR RESTRICTING CONDITIONS WILL CONTINUE TO INCREASE FRIDAY
NIGHT INTO SATURDAY MORNING.
OUTLOOK...
SAT-TUE...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOCAL REDUCTIONS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DEVOIR/LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
945 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST INTO THE REGION TODAY AND
TONIGHT...BRINGING CONSIDERABLE CLOUDINESS THROUGHOUT THE DAY AND
A CHANCE OF SHOWERS BY LATER THIS AFTERNOON. THE FRONT WILL STALL
OVER THE REGION THIS WEEKEND...BRINGING VARIABLE CLOUDS AND A
CHANCE OF SHOWERS EACH AFTERNOON. A COLD FRONT WILL MOVE ACROSS
THE AREA MONDAY NIGHT AND TUESDAY...USHERING IN A COOL AIRMASS
FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE DRIFTING OFF OF THE MID ATLANTIC COAST THIS
MORNING. A FAIRLY VIGOROUS UPPER SHORTWAVE WILL BE MOVING EAST
ACROSS THE LWR GLAKES REGION LATE THIS MORNING...THEN ACROSS NEW
YORK AND NRN PENN THIS AFTERNOON.
A RATHER LARGE AREA OF LGT-MDT RAIN SHOWERS ACROSS SE MICH AND NRN
OHIO AT 1330Z IS PROGGED BY THE HRRR TO BREAK UP A BIT AS IT STREAMS
EAST ACROSS NRN PENN DURING THE AFTERNOON HOURS.
ELSEWHERE...LIGHT WIND AND PERIODS OF SUNSHINE THROUGH THE MID AND
HIGH BKN-OVERCAST LAYER OF CLOUDS WILL DOMINATE THE WEATHER THROUGH
EARLY THIS AFTERNOON ACROSS THE SERN HALF OF THE STATE...WITH
ISOLATED SHRA/TSRA POSSIBLE LATER THIS AFTERNOON AS THE WARM FROM
APPROACHES FROM THE OHIO VALLEY.
INCREASING HUMIDITY/INSTABILITY ASSOC WITH ARRIVAL OF THE WARM FRONT
WILL RESULT IN BUILDING CU BY AFTN ACROSS THE ALLEGHENY PLATEAU
ALONG WITH SCT PM CONVECTION. BEST OVERALL CHC OF RAIN /70-80
PERCENT/ THIS AFTERNOON APPEARS TO BE OVR THE NW MTNS...CLOSEST TO
TRACK OF NEXT SHORTWAVE CROSSING OVR THE E GRT LKS. HAVE MODIFIED
POPS UPWARD A BIT ACROSS NRN PENN AFTER 18Z...BUT LEFT LOW POPS OF
ONLY ARND 15 PCT FOR A LATE DAY SHRA ACROSS THE SE COUNTIES...WHERE
AIR MASS WILL REMAIN RELATIVELY STABLE EAST OF FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WARM FRONT GETS HUNG UP ACROSS N CENTRAL TONIGHT AS FLAT RIDGE
CONTINUES TO BE IMPACTED BY EMBEDDED SHORTWAVE TROFS. THIS WILL
KEEP CHC OF SHOWERS GOING...ALTHOUGH MUCH OF THE TIME WILL BE RAIN
FREE IN MOST AREAS. BEST CHC FOR SHOWERS WILL COME SATURDAY
AFTERNOON OVER THE WESTERN AND NORTHERN HIGH TERRAIN AS CAPES GROW
TO SEVERAL HUNDRED J/KG AND BOUNDARY PROVIDES A FOCUS/TRIGGER FOR
INITIATION. MINS TONIGHT WILL BE MILD...GENERALLY RANGING FROM THE
UPPER 50S NORTH THROUGH THE 60S SOUTH. HIGHS ON SATURDAY WILL
RANGE FROM THE MID 70S NORTH TO AROUND 80 SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE SURFACE LOW REACHING THE UPPER MIDWEST BY EARLY FRIDAY WILL BE
PRECEDED BY A WARM FRONT AS IT CROSSES THE GREAT LAKES/OH VALLEY
AND REACHES THE MID ATLANTIC AND NORTHEAST STATES BY THIS
WEEKEND. A SUFFICIENT INCREASE IN MOISTURE (PWS) AND INSTABILITY
WILL SUPPORT SCATTERED CONVECTION INTO EARLY NEXT WEEK WITH THE
WARM FRONT AND ALSO WITH A TRAILING SURFACE TROUGH EXTENDING
TOWARD THE NORTHERN APPALACHIANS PROVIDING SOME ADDITIONAL LIFT.
A WELL-DEFINED COLD FRONT SHOULD CROSS THE REGION LATER MONDAY
INTO EARLY TUESDAY WITH THE GREATEST RISK FOR WIDESPREAD SHOWERS
AND T-STORMS. THE PARENT SHORTWAVE TROUGH WILL SUPPRESS THE ERN
RIDGE AND ALLOW COOLER/DRIER AIR TO ARRIVE BY MIDWEEK...AS HIGH
PRESSURE SETTLES SEWD FROM THE UPPER PLAINS INTO THE MID ATLC.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/... VARIABLE AMOUNTS/THICKNESS
OF MID AND HIGH CLOUDS WILL OCCUR TODAY ACROSS MUCH OF CENTRAL AND
SERN PENN...AHEAD OF A WARM FRONT LIFTING NE FROM THE OHIO RIVER
VALLEY. ACROSS OUR NW/NCENT MTN ZONES...CLOUDS WILL LOWER AND
THICKEN TODAY...THOUGH THE MAINLY MID CLOUD DECK SHOULD REMAIN IN
THE VFR RANGE THROUGH MOST OF THE DAY.
LATEST HI RESOLUTION MODEL RUNS BRING IN THE SHOWERS THROUGH NWRN
PA BEGINNING AROUND 18Z AND MOVING EASTWARD THROUGH 00Z
/IMPACTING TAF SITES MAINLY ALONG AND NORTH OF A KDUJ TO KIPT
LINE...OR NORTH OF INTERSTATE 80/.
MVFR TO IFR POSSIBLE IN ANY OF THE SHOWERS AND THUNDERSTORMS. THE
CHANCES FOR RESTRICTING CONDITIONS WILL CONTINUE TO INCREASE FRIDAY
NIGHT INTO SATURDAY MORNING.
OUTLOOK...
SAT-TUE...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOCAL REDUCTIONS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DEVOIR
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
901 AM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST INTO THE REGION TODAY AND
TONIGHT...BRINGING CONSIDERABLE CLOUDINESS THROUGHOUT THE DAY AND
A CHANCE OF SHOWERS BY LATER THIS AFTERNOON. THE FRONT WILL STALL
OVER THE REGION THIS WEEKEND...BRINGING VARIABLE CLOUDS AND A
CHANCE OF SHOWERS EACH AFTERNOON. A COLD FRONT WILL MOVE ACROSS
THE AREA MONDAY NIGHT AND TUESDAY...USHERING IN A COOL AIRMASS
FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE DRIFTING OFF OF THE MID ATLANTIC COAST THIS
MORNING. A FAIRLY VIGOROUS UPPER SHORTWAVE WILL BE MOVING EAST
ACROSS THE LWR GLAKES REGION LATE THIS MORNING...THEN ACROSS HEW
YORK AND NRN PENN THIS AFTERNOON.
A RATHER LARGE AREA OF MDT RAIN SHOWERS ACROSS SE MICH AND NRN
OHIO IS PROGGED BY THE HRRR TO BREAK UP A BIT AS STREAM EAST
ACROSS NRN PENN DURING THE AFTERNOON HOURS. ELSEWHERE...
SOME BREAK IN THE MID AND HIGH OVERCAST WILL DOMINATE THE WEATHER
THROUGH EARLY THIS AFTERNOON ACROSS THE SERN HALF OF THE STATE
WITH ISOLATED SHRA/TSRA POSSIBLE LATER THIS AFTERNOON AS THE WARM
FROM APPROACHES FROM THE OHIO VALLEY.
INCREASING HUMIDITY/ INSTABILITY ASSOC WITH ARRIVAL OF WARM FRONT
WILL RESULT IN BUILDING CU BY AFTN ACROSS THE ALLEGHENY PLATEAU
ALONG WITH SCT PM CONVECTION. BEST CHC OF RAIN WOULD APPEAR TO BE
OVR THE NW MTNS...CLOSEST TO TRACK OF NEXT SHORTWAVE CROSSING OVR
THE E GRT LKS. HAVE MODIFIED POPS UPWARD A BIT ACROSS NRN PENN
AFTER 18Z...BUT LEFT LOW POPS OF ONLY ARND 15 PCT FOR A LATE DAY
SHRA ACROSS THE SE COUNTIES...WHERE AIR MASS WILL REMAIN
RELATIVELY STABLE EAST OF FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WARM FRONT GETS HUNG UP ACROSS N CENTRAL TONIGHT AS FLAT RIDGE
CONTINUES TO BE IMPACTED BY EMBEDDED SHORTWAVE TROFS. THIS WILL
KEEP CHC OF SHOWERS GOING...ALTHOUGH MUCH OF THE TIME WILL BE RAIN
FREE IN MOST AREAS. BEST CHC FOR SHOWERS WILL COME SATURDAY
AFTERNOON OVER THE WESTERN AND NORTHERN HIGH TERRAIN AS CAPES GROW
TO SEVERAL HUNDRED J/KG AND BOUNDARY PROVIDES A FOCUS/TRIGGER FOR
INITIATION. MINS TONIGHT WILL BE MILD...GENERALLY RANGING FROM THE
UPPER 50S NORTH THROUGH THE 60S SOUTH. HIGHS ON SATURDAY WILL
RANGE FROM THE MID 70S NORTH TO AROUND 80 SOUTH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE SURFACE LOW REACHING THE UPPER MIDWEST BY EARLY FRIDAY WILL BE
PRECEDED BY A WARM FRONT AS IT CROSSES THE GREAT LAKES/OH VALLEY
AND REACHES THE MID ATLANTIC AND NORTHEAST STATES BY THIS
WEEKEND. A SUFFICIENT INCREASE IN MOISTURE (PWS) AND INSTABILITY
WILL SUPPORT SCATTERED CONVECTION INTO EARLY NEXT WEEK WITH THE
WARM FRONT AND ALSO WITH A TRAILING SURFACE TROUGH EXTENDING
TOWARD THE NORTHERN APPALACHIANS PROVIDING SOME ADDITIONAL LIFT.
A WELL-DEFINED COLD FRONT SHOULD CROSS THE REGION LATER MONDAY
INTO EARLY TUESDAY WITH THE GREATEST RISK FOR WIDESPREAD SHOWERS
AND T-STORMS. THE PARENT SHORTWAVE TROUGH WILL SUPPRESS THE ERN
RIDGE AND ALLOW COOLER/DRIER AIR TO ARRIVE BY MIDWEEK...AS HIGH
PRESSURE SETTLES SEWD FROM THE UPPER PLAINS INTO THE MID ATLC.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
CLOUDS CONTINUE TO THICKEN TODAY THROUGH CLOUD DECKS SHOULD REMAIN
IN THE VFR RANGE THROUGH MOST OF THE DAY. LATEST MODEL RUNS BRING
IN THE SHOWERS THROUGH CENTRAL PA BEGINNING AROUND 18Z AND MOVING
EASTWARD THROUGH 00Z. VFR SHOULD STILL DOMINATE WITH MVFR TO IFR
POSSIBLE IN THE SHOWERS AND THUNDERSTORMS.THE CHANCES FOR
RESTRICTING CONDITIONS WILL CONTINUE TO INCREASE FRIDAY NIGHT INTO
SATURDAY MORNING.
OUTLOOK...
SAT-TUE...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOCAL REDUCTIONS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DEVOIR
LONG TERM...STEINBUGL
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
432 AM EDT FRI MAY 15 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL KEEP THE PIEDMONT MOSTLY DRY
INTO THE WEEKEND...BUT INCREASING MOISTURE ON THE WESTERN EDGE OF
THE SURFACE HIGH WILL BRING PRECIPITATION CHANCES OVER THE
MOUNTAINS. A COLD FRONT WILL PUSH THROUGH THE REGION EARLY NEXT WEEK
ALLOWING BETTER PRECIPITATION CHANCES FOR THE ENTIRE REGION MONDAY
AND TUESDAY. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL RETURN
BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EDT...WATER VAPOR IMAGERY SHOWS A SHORTWAVE CROSSING
THE BASE OF THE SOUTHERN APPALACHIANS EARLY THIS MORNING. THIS
FEATURE IS COMBINING WITH SOUTHERLY UPSLOPE FLOW TO PRODUCE ISOLATED
SHOWERS OVER THE WESTERN HALF OF THE FORECAST AREA THIS
MORNING...AND SPOTTY LIGHT SHOWERS WILL LIKELY MOVE EAST INTO THE
PIEDMONT UNDER THE PASSING WAVE THROUGH DAYBREAK. THE SHORTWAVE WILL
MOVE EAST OF THE AREA BY LATE MORNING...WITH MOST AFTN AND EVENING
ISOLD TO SCATTERED SHOWERS AND TSTMS AFFECTING MAINLY THE MTNS IN
WEAK UPSLOPE AND LOW LEVEL CONVERGENCE ACROSS THE HIGHER TERRAIN.
CLOUDINESS WILL KEEP INSTABILITY CONTAINED TODAY AND ALSO PUT A
DAMPER ON MAX TEMPS IN SPITE OF THE WARMING THICKNESSES. A SHIELD OF
MID AND HIGH CLOUDS IS ALREADY IN PLACE ACROSS THE REGION. SCT TO
BKN LOWER LEVEL STRATOCUMULUS IS FILLING IN IN THE MOIST SOUTHERLY
FLOW AROUND THE COASTAL HIGH PRESSURE CENTER...AND ANY DEGREE OF
HEATING WILL ALLOW CLOUDS TO FILL BACK IN THROUGH THE DAY. MAXES
WILL BE MAINLY IN THE 70S...EXCEPT FOR SOME 60S ALONG THE HIGHER
TERRAIN THIS AFTN...AND AROUND 80 IN THE LOWER PIEDMONT.
A 500 MB RIDGE WILL BUILD OVER THE REGION THE REST OF THIS AFTERNOON
THROUGH TONIGHT. S TO SW UPSLOPE FLOW WILL CONTINUE IN THE SW MTNS
INTO THE OVERNIGHT HOURS...WITH THE BEST CHANCE OF LINGERING ISOLD
NOCTURNAL SHOWERS IN THIS AREA. WILL LEAN TOWARD THE WARMER BIAS
CORRECTED MIN TEMPS FOR TONIGHT GIVEN THE CONTINUED CLOUDS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 200 AM FRI...UPPER RIDGE AMPLIFIES OVER THE SOUTHEAST OVER THE
WEEKEND. ANY SIGNIFICANT FEATURES REMAIN TO OUR NORTH AND WEST. SSW
TO SW FLOW CONTINUES IN THE LOW LEVELS WHICH WILL PROVIDE PLENTIFUL
MOISTURE AND HELP INITIATE CONVECTION OVER THE HIGHER TERRAIN VIA
UPSLOPING. THROUGH SUNDAY THE BERMUDA HIGH REMAINS DOMINANT...AND
LAPSE RATES ARE TOO POOR OVER THE PIEDMONT TO EXPECT CONVECTION
THERE. ON SUNDAY A DEEP LOW WILL MOVE EWD OUT OF THE DAKOTAS ON AN
EVENTUAL TRACK ACRS THE NRN GREAT LAKES. AS GRADIENT TIGHTENS ON THE
UPSTREAM SIDE OF THE EAST COAST RIDGE...LOW LEVEL FLOW VEERS SUN
NIGHT TO MORE WESTERLY. COVERAGE WILL WANE SUNDAY NIGHT BUT ISOLATED
ACTIVITY MAY CONTINUE NEAR THE TENN BORDER INTO MON MRNG. TEMPS WILL
BE A CATEGORY OR SO ABOVE NORMAL DURING THE PERIOD.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 200 AM FRI...POPS PEAK MONDAY AS PREFRONTAL CONVERGENCE AND
MOISTURE COINCIDE WITH DIURNAL INSTABILITY...REMAINING ELEVATED UNTIL
COLD FRONT PASSES EARLY TUE. MONDAY IS ALSO EXPECTED TO BE THE
WARMEST DAY OF THE WEEK AS THICKNESSES PEAK. MAX TEMPS WILL BE 7-10
DEGREES ABOVE NORMAL. DRY CONTINENTAL HIGH PRESSURE RETURNS IN ITS
WAKE LASTING THRU WED...THOUGH TEMPS REMAIN ABOVE NORMAL. WHILE THE
15/00Z GFS AND 14/12Z EC BEAR LITTLE DIFFERENCE PRIOR TO THIS
TIME...BY WED NIGHT THEY HAVE DIVERGED IN THEIR DEPICTION OF THE
UPPER PATTERN OVER THE WEST COAST. THIS LEADS TO SOME SUBTLE
DIFFERENCES OVER OUR AREA FOR THE LATE WEEK. WHILE THE UPPER FLOW IS
OF LOW AMPLITUDE ON BOTH...THE EC IS SLIGHTLY CYCLONIC OVER THE AREA
WHILE THE GFS IS ZONAL. A WEAK BAROCLINIC ZONE APPEARS LIKELY TO BE
IN PLAY ACROSS THE UPPER SOUTH...WHICH WOULD HELP RE-ACTIVATE MAINLY
DIURNAL CONVECTION OVER PARTS OF THE AREA. TEMPS WILL TREND DOWNWARD
SLIGHTLY LATER IN THE WEEK...THOUGH WITH MAXES REMAINING ABOVE NORMAL
AND WITH RESTRICTED DIURNAL RANGES DUE TO CLOUD COVER.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
AT KCLT...MVFR STRATUS HAS SET UP QUICKLY THIS MORNING ON THE
STRENGTH OF LIGHT BUT MOIST SOUTHERLY FLOW JUST OFF THE SURFACE. THE
CONSENSUS OF MODEL PROFILES AND MOS GUIDANCE REMAINS THAT A FAIRLY
PROLONGED PERIOD OF MVFR IS IN STORE THROUGH THE LATE MORNING
HOURS...POSSIBLY LINGERING INTO EARLY AFTERNOON. THE MET GUIDANCE
AND RAP PROFILES ALSO HINT THAT PERIODS OF DAYBREAK IFR WILL BE
POSSIBLE...BUT THIS HAS YET TO OCCUR AT ANY OF THE NEARBY OBSERVING
LOCATIONS...SO WILL KEEP THE FORECAST NO WORSE THAN MVFR FOR NOW.
CIGS WILL SLOWLY RISE BACK TO VFR THIS AFTN AND SCATTER TOWARD
EVENING. EXPECT SE TO S FLOW THROUGH THE PERIOD AT SPEEDS LESS THAN
10 KT.
ELSEWHERE...VFR STRATUS/STRATOCUMULUS CIGS CONTINUE TO DEVELOP AND
LOWER THIS MORNING UNDER MOIST SRLY FLOW. THERE IS SOME POTENTIAL
FOR IFR CIGS AROUND DAYBREAK THROUGHOUT...BUT CHANCES APPEAR BEST IN
MODEL SOUNDINGS OVER KAVL...SO WILL FEATURE TEMPO IFR THERE. THE
CLOUDS SHOULD LARGELY PRECLUDE ANY SIGNIFICANT MORNING FOG ISSUES.
EXPECT CIGS TO SLOWLY RISE THROUGH MVFR THROUGH LATE MORNING...WITH
VFR CIGS LIKELY THIS AFTN...SCATTERING THIS EVENING. EXPECT SOME
DEGREE OF SOUTHERLY FLOW THROUGH THE PERIOD...WITH SPEEDS LESS THAN
10 KT.
OUTLOOK...MOISTURE WILL GRADUALLY INCREASE THROUGH THE
WEEKEND...WITH DIURNAL CONVECTIVE CHANCES INCREASING AS
WELL...ESPECIALLY OVER THE MTNS. THE POTENTIAL FOR EARLY MORNING
STRATUS AND FOG WILL ALSO INCREASE OVER THE WEEKEND INTO EARLY NEXT
WEEK.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-06Z
KCLT HIGH 95% HIGH 84% HIGH 100% HIGH 100%
KGSP HIGH 90% HIGH 82% HIGH 100% HIGH 100%
KAVL HIGH 93% HIGH 93% HIGH 100% HIGH 100%
KHKY HIGH 93% HIGH 90% HIGH 100% HIGH 100%
KGMU HIGH 87% HIGH 89% HIGH 100% HIGH 100%
KAND HIGH 90% HIGH 90% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1054 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 935 PM CDT SAT MAY 16 2015
WENT AHEAD AND TWEAKED THE POPS BASED ON A BLEND OF THE HRRR AND
LATEST 00Z NAM FOR THE REST OF TONIGHT AND ALSO FOR SUNDAY DAY
PERIOD. A LULL IN THE ACTION IS GREETING THE FORECAST AREA AT THIS
TIME...AND THIS TREND WILL LIKELY REMAIN THIS WAY FOR THE REST OF
THE EVENING. HOWEVER AFTER MIDNIGHT AND SUNDAY MORNING...THE HRRR
AND NAM12 ARE BOTH IN VERY GOOD AGREEMENT IN BRINGING ANOTHER
ROUND OF RAINFALL NORTHWARD FIRST INTO OUR EASTERN ZONES...THEN
TAILING BACK WESTWARD IN A COMMA HEAD SHAPE FOLLOWING THE MID
LEVEL TROWALING AHEAD OF THE UPPER AND SURFACE LOW. THIS SEEMS
VERY REASONABLE SO HOOKED ONTO THOSE SOLUTIONS...AND THE BLOB OF
RAINFALL IN EASTERN KS MOVING INTO EXTREME SOUTHEAST NEB IS
CERTAINLY HARD TO IGNORE. THE RAINFALL SHOULD EVENTUALLY
RETROGRADE BACK INTO OUR WESTERN ZONES VERY LATE TONIGHT AND
SUNDAY MORNING WHERE SOME BENEFICIAL RAINFALL SHOULD OCCUR. DOUBT
THERE WILL MUCH IN THE WAY OF SEVERE WEATHER IF ANY AT ALL DUE TO
A PERSISTENT LACK OF DIRECTIONAL WIND SHEAR AND ALSO A LOSS OF LOW
LEVEL HEATING AS THE NIGHT PROGRESSES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 310 PM CDT SAT MAY 16 2015
JET MAX LIFTING NORTH OVER THE WESTERN HIGH PLAINS WILL SWING THE
ENTRANCE REGION THROUGH THE AREA LATE THIS AFTERNOON. A SMALL
MCV/WEAK WAVE IS LIFTING NORTH THROUGH THE WESTERN CWA THIS
AFTERNOON. ISOLATED THUNDERSTORMS HAVE DEVELOPED WITHIN AND AHEAD OF
THIS FEATURE AND TO THE SOUTH OF IT LITTLE IF ANYTHING IS OCCURRING.
THIS TENDS TO MAKE SENSE AS THERE IS LITTLE TO NO CONVERGENCE BEHIND
THIS WEAK FEATURE. SO WILL CONTINUE TO BACK OFF OF POPS THROUGH THE
AFTERNOON AND EVENING. SO...EXPECT A BETTER CHANCE TO THE WEST OF
OUR AREA AND OF COURSE TO THE SOUTH. THE ACTIVITY TO THE SOUTH WILL
BE THE MOST IMPORTANT TO WATCH AS THAT WILL LIKELY ADVECT/DEVELOP
NORTH THROUGH THE EVENING. AGAIN...INSTABILITY MARGINAL SO QUARTERS
TO MAYBE HALF DOLLARS WILL BE THE MAIN THREAT. WILL ALSO NEED TO
WATCH FOR A SMALL CHANCE FOR SOME FLASH FLOODING...ESPECIALLY FAR
SOUTHEAST SD...NORTHWEST IA AND SOUTHWEST MN WHERE HEAVY RAIN HAS
FALLEN AS OF LATE AND OR THE MODELS ARE HINTING AT SOME HIGHER
RAINFALL POTENTIAL. THE 3 HOUR FLASH FLOOD GUIDANCE IN THESE
LOCATIONS RUNNING GENERALLY LESS THAN 2 INCHES.
DRY SLOT SWINGS NORTH LATE TONIGHT INTO SUNDAY MORNING WITH RAIN AND
ISOLATED THUNDERSTORMS EXPECTED TO CONTINUE IN THE NORTHERN AND
WESTERN CWA. AS THE LOW PRESSURE WRAPS UP AND SHIFTS EASTWARD A COLD
FRONT AT THE SURFACE WILL WORK EAST KEEPING HIGHS IN CHECK OVER THE
WESTERN CWA. LOWS TONIGHT MAINLY UPPER 50S TO LOWER 60S WITH HIGHS
SUNDAY RANGING FROM THE MID 60S IN CENTRAL SD TO THE MID 70S IN
NORTHWEST IOWA.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CDT SAT MAY 16 2015
COOL AND BREEZY CONDITIONS ARE EXPECTED TO BEGIN THE PERIOD AS LOW
PRESSURE CONTINUES TO LIFT OFF TO THE NORTHEAST AND STRONG
NORTHWESTERLY WINDS DRAW UNSEASONABLY COOL AIR INTO THE REGION. 850
HPA TEMPS TUMBLE THROUGHOUT THE NIGHT AND REMAIN NEAR ZERO DURING
THE DAY ON MONDAY. 12Z ECMWF HAS WARMED SLIGHTLY OVER THE 00Z
RUNS...BUT WITH LINGERING CLOUD COVER....SHOULD BE A COOL DAY ACROSS
THE AREA.
AS WINDS DROP OFF MONDAY NIGHT WILL NEED TO KEEP AN EYE ON THE
FROST/FREEZE POTENTIAL. WITH DRY AIR MASS AND LIGHT WINDS...EXPECT
TEMPERATURES TO FALL WITHIN A FEW DEGREES OF FREEZING.
COOL TEMPERATURES CONTINUE TUESDAY INTO WEDNESDAY. MODELS SHOW A
UPPER LEVEL LOW SHEARING OUT AND MOVING ACROSS THE AREA. NOT MUCH
IN THE WAY TO WORK WITH MOISTURE WISE...AND HAVE CUT BACK POPS ALONG
WITH THUNDER MENTION.
COOL TEMPERATURES CONTINUE THROUGH THE END OF THE WEEK WITH A MORE
ACTIVE PATTERN POTENTIALLY FOR THE WEEKEND AS LARGE UPPER LEVEL
TROUGH ACROSS THE WEST SHIFTS EAST. WITH ONGOING WEATHER
CONCERNS...KEPT FORECAST FAIRLY CLOSE TO GUIDANCE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1051 PM CDT SAT MAY 16 2015
THE LATEST HRRR AND NAM12 MODELS CONTINUE TO BE IN PRETTY GOOD
AGREEMENT IN BRINGING THE NEXT ROUND OF RAINFALL NORTHWARD LATE
TONIGHT...THEN CURLING THE PRECIPITATION WESTWARD TOWARD DAY BREAK
SUNDAY. THERE IS A LOT OF RAINFALL UPSTREAM IN EASTERN NEB AND
WESTERN KS...SO HAVE NO REASON TO DOUBT THIS SCENARIO YET SO
INCLUDED THE RAIN IN THE TAFS. THE BIGGEST QUESTION MARK IS THE
AMOUNT OF THUNDERSTORMS. THERE COULD BE ELEVATED STORMS EMBEDDED
IN THE RAIN...SO INCLUDED THE MENTION OF TSRA ONLY IN A TEMPO
GROUP FOR OUR THREE SITES. FURTHERMORE...THE HUMIDITY TIME
SECTIONS AND MODEL SOUNDINGS SHOW WIDESPREAD MVFR TO POSSIBLE
LOWER END IFR CONDITIONS TAKING OVER LATE TONIGHT AND SUNDAY
MORNING NORTH OF I 90 IMPACTING THE KHON TAF SITE. HEADING FURTHER
SOUTHWARD...THE CEILINGS WILL BE HIGHER WITH LESS RAINFALL ON
SUNDAY. THEREFORE AM LESS PESSIMISTIC WITH THE CEILINGS IN THE
KFSD AND KSUX TAF SITES.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...08
LONG TERM...
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
935 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 935 PM CDT SAT MAY 16 2015
WENT AHEAD AND TWEAKED THE POPS BASED ON A BLEND OF THE HRRR AND
LATEST 00Z NAM FOR THE REST OF TONIGHT AND ALSO FOR SUNDAY DAY
PERIOD. A LULL IN THE ACTION IS GREETING THE FORECAST AREA AT THIS
TIME...AND THIS TREND WILL LIKELY REMAIN THIS WAY FOR THE REST OF
THE EVENING. HOWEVER AFTER MIDNIGHT AND SUNDAY MORNING...THE HRRR
AND NAM12 ARE BOTH IN VERY GOOD AGREEMENT IN BRINGING ANOTHER
ROUND OF RAINFALL NORTHWARD FIRST INTO OUR EASTERN ZONES...THEN
TAILING BACK WESTWARD IN A COMMA HEAD SHAPE FOLLOWING THE MID
LEVEL TROWALING AHEAD OF THE UPPER AND SURFACE LOW. THIS SEEMS
VERY REASONABLE SO HOOKED ONTO THOSE SOLUTIONS...AND THE BLOB OF
RAINFALL IN EASTERN KS MOVING INTO EXTREME SOUTHEAST NEB IS
CERTAINLY HARD TO IGNORE. THE RAINFALL SHOULD EVENTUALLY
RETROGRADE BACK INTO OUR WESTERN ZONES VERY LATE TONIGHT AND
SUNDAY MORNING WHERE SOME BENEFICIAL RAINFALL SHOULD OCCUR. DOUBT
THERE WILL MUCH IN THE WAY OF SEVERE WEATHER IF ANY AT ALL DUE TO
A PERSISTENT LACK OF DIRECTIONAL WIND SHEAR AND ALSO A LOSS OF LOW
LEVEL HEATING AS THE NIGHT PROGRESSES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 310 PM CDT SAT MAY 16 2015
JET MAX LIFTING NORTH OVER THE WESTERN HIGH PLAINS WILL SWING THE
ENTRANCE REGION THROUGH THE AREA LATE THIS AFTERNOON. A SMALL
MCV/WEAK WAVE IS LIFTING NORTH THROUGH THE WESTERN CWA THIS
AFTERNOON. ISOLATED THUNDERSTORMS HAVE DEVELOPED WITHIN AND AHEAD OF
THIS FEATURE AND TO THE SOUTH OF IT LITTLE IF ANYTHING IS OCCURRING.
THIS TENDS TO MAKE SENSE AS THERE IS LITTLE TO NO CONVERGENCE BEHIND
THIS WEAK FEATURE. SO WILL CONTINUE TO BACK OFF OF POPS THROUGH THE
AFTERNOON AND EVENING. SO...EXPECT A BETTER CHANCE TO THE WEST OF
OUR AREA AND OF COURSE TO THE SOUTH. THE ACTIVITY TO THE SOUTH WILL
BE THE MOST IMPORTANT TO WATCH AS THAT WILL LIKELY ADVECT/DEVELOP
NORTH THROUGH THE EVENING. AGAIN...INSTABILITY MARGINAL SO QUARTERS
TO MAYBE HALF DOLLARS WILL BE THE MAIN THREAT. WILL ALSO NEED TO
WATCH FOR A SMALL CHANCE FOR SOME FLASH FLOODING...ESPECIALLY FAR
SOUTHEAST SD...NORTHWEST IA AND SOUTHWEST MN WHERE HEAVY RAIN HAS
FALLEN AS OF LATE AND OR THE MODELS ARE HINTING AT SOME HIGHER
RAINFALL POTENTIAL. THE 3 HOUR FLASH FLOOD GUIDANCE IN THESE
LOCATIONS RUNNING GENERALLY LESS THAN 2 INCHES.
DRY SLOT SWINGS NORTH LATE TONIGHT INTO SUNDAY MORNING WITH RAIN AND
ISOLATED THUNDERSTORMS EXPECTED TO CONTINUE IN THE NORTHERN AND
WESTERN CWA. AS THE LOW PRESSURE WRAPS UP AND SHIFTS EASTWARD A COLD
FRONT AT THE SURFACE WILL WORK EAST KEEPING HIGHS IN CHECK OVER THE
WESTERN CWA. LOWS TONIGHT MAINLY UPPER 50S TO LOWER 60S WITH HIGHS
SUNDAY RANGING FROM THE MID 60S IN CENTRAL SD TO THE MID 70S IN
NORTHWEST IOWA.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CDT SAT MAY 16 2015
COOL AND BREEZY CONDITIONS ARE EXPECTED TO BEGIN THE PERIOD AS LOW
PRESSURE CONTINUES TO LIFT OFF TO THE NORTHEAST AND STRONG
NORTHWESTERLY WINDS DRAW UNSEASONABLY COOL AIR INTO THE REGION. 850
HPA TEMPS TUMBLE THROUGHOUT THE NIGHT AND REMAIN NEAR ZERO DURING
THE DAY ON MONDAY. 12Z ECMWF HAS WARMED SLIGHTLY OVER THE 00Z
RUNS...BUT WITH LINGERING CLOUD COVER....SHOULD BE A COOL DAY ACROSS
THE AREA.
AS WINDS DROP OFF MONDAY NIGHT WILL NEED TO KEEP AN EYE ON THE
FROST/FREEZE POTENTIAL. WITH DRY AIR MASS AND LIGHT WINDS...EXPECT
TEMPERATURES TO FALL WITHIN A FEW DEGREES OF FREEZING.
COOL TEMPERATURES CONTINUE TUESDAY INTO WEDNESDAY. MODELS SHOW A
UPPER LEVEL LOW SHEARING OUT AND MOVING ACROSS THE AREA. NOT MUCH
IN THE WAY TO WORK WITH MOISTURE WISE...AND HAVE CUT BACK POPS ALONG
WITH THUNDER MENTION.
COOL TEMPERATURES CONTINUE THROUGH THE END OF THE WEEK WITH A MORE
ACTIVE PATTERN POTENTIALLY FOR THE WEEKEND AS LARGE UPPER LEVEL
TROUGH ACROSS THE WEST SHIFTS EAST. WITH ONGOING WEATHER
CONCERNS...KEPT FORECAST FAIRLY CLOSE TO GUIDANCE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 626 PM CDT SAT MAY 16 2015
FOCUS ON TIMING OF THUNDERSTORMS THE MAIN CHALLENGE THIS TAF
PERIOD. SCATTERED CONVECTION EARLY THIS EVENING IS EXPECTED TO BE
EAST OF THE TAF SITES IN THE SHORT TERM...BUT THE CONVECTION
ACROSS SOUTHERN NEBRASKA IS EXPECTED TO LIFT NORTH AND APPROACH
THE I-29 CORRIDOR TOWARDS THE 06Z TIME FRAME. COLD FRONT STARTS TO
PIVOT IN FROM THE WEST...CREATING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS THROUGH THE MORNING HOURS AT KHON. CEILINGS WILL
MAINLY REMAIN IN THE MVFR RANGE ON SUNDAY...THOUGH KSUX COULD END
UP IN THE DRY SLOT SUNDAY AFTERNOON LEADING TO VFR.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...08
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
900 PM CDT SAT MAY 16 2015
.DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES
INDICATE A COUPLE OF SHORTWAVE TROUGH LOCATED ACROSS THE LOWER
MISSISSIPPI VALLEY THIS EVENING. THE FIRST SHORTWAVE IS LOCATED
OVER WEST TENNESSEE AND THE SECOND SHORTWAVE LOCATED OVER
CENTRAL/SOUTHERN MISSISSIPPI THIS EVENING. OVERALL CONVECTIVE
ACTIVITY HAS BEEN DIMINISHING WITH THE LOSS OF DAYTIME
INSTABILITY AND WITH THESE SHORTWAVES MOVING AWAY FROM THE MID
SOUTH. LATEST HRRR/00Z WRF AGREE WITH SHOWERS AND THUNDERSTORMS
DIMINISHING WITH COVERAGE THROUGHOUT THE REMAINDER OF THE NIGHT.
WILL UPDATE POPS AND ALL OTHER ELEMENTS TO REFLECT CURRENT TRENDS.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
&&
.PREV DISCUSSION... /ISSUED 627 PM CDT SAT MAY 16 2015/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 311 PM CDT SAT MAY 16 2015/
POPCORN TYPE SHOWERS AND THUNDERSTORMS ARE OCCURRING ACROSS THE
MIDSOUTH AND SURROUNDING AREAS. LATEST HRRR SHOWS THIS ACTIVITY
CONTINUING THROUGH AROUND 7-8 PM. THEREAFTER...ACTIVITY WILL
DISSIPATE FROM THE LOSS OF DAYTIME HEATING. EXPECT THE REMAINDER
OF THE NIGHT TO BE TRANQUIL. WILL LEAVE 30 POPS IN CASE A STRAY
SHOWER OR THUNDERSTORM DEVELOPS. LOWS WILL BE IN THE MID TO UPPER
60S.
A SEVERE LINE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP
THIS EVENING ACROSS OKLAHOMA...KANSAS...AND TEXAS. MODELS HAVE
BEEN PRETTY CONSISTENT WITH BRINGING THE REMNANTS OF THIS LINE
INTO EASTERN ARKANSAS AROUND SUNRISE. STILL EXPECT THE LINE TO BE
IN THE DYING PHASES AS IT MOVES IN. THE LINE WILL FALL APART AS IT
REACHES THE MS RIVER DURING THE MORNING. HOWEVER...REDEVELOPMENT
ALONG LEFTOVER BOUNDARIES WILL BE POSSIBLE ALONG AND EAST OF THE
MISSISSIPPI RIVER FROM MID-MORNING ON SUNDAY INTO THE AFTERNOON
HOURS.
EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DIE OUT AGAIN BY 7PM
SUNDAY EVENING. NEW DEVELOPMENT MAY OCCUR ALONG AND WEST OF THE
MISSISSIPPI RIVER DURING THE LATE EVENING TO OVERNIGHT HOURS AS A
SHORTWAVE MOVES INTO THE REGION. THIS ACTIVITY WILL BLOSSOM OVER
THE CWA INTO MONDAY.
THE COLD FRONT IS STILL EXPECTED TO MOVE INTO THE AREA MONDAY
NIGHT INTO TUESDAY. SCATTERED CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL CONTINUE ALONG AND AHEAD OF THE FRONT.
THE ECMWF AND GFS DIFFER ON HOW2 FAR SOUTH THE FRONT WILL
PROGRESS. IF THE ECMWF IS CORRECT...TUESDAY NIGHT MAY BE THE ONLY
DRY PERIOD BEFORE THE FRONT MOVES BACK NORTH AS A WARM FRONT.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL OCCUR ALONG AND AHEAD
OF THE WARM FRONT. THE FRONT WILL RETURN SOUTHWARD AS A COLD FRONT
ON THURSDAY. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
LIKELY OCCUR ON THURSDAY.
HIGH PRESSURE WILL THEN BUILD INTO THE AREA ON FRIDAY.
&&
.AVIATION...
00Z TAFS
SCATTERED SHRA AND TSRAS WILL DIMINISH IN BOTH INTENSITY AND
COVERAGE LATE THIS AFTERNOON AND OVERNIGHT. THE CHANCE FOR
ADDITIONAL ON STATION THUNDER LOOKS LOW AT JBR AND MEM...AND
SHOULD END IN THE NEXT HOUR OR TWO AT MKL AND TUP. QUIET
OVERNIGHT THEN LOW CLOUDS SHOULD REDEVELOP LATER TONIGHT INTO
EARLY SUNDAY...ESPECIALLY AT KJBR AND KTUP. A WEAKENING LINE OF
SHRAS AND TSRAS WILL BE PUSHING INTO THE MIDSOUTH SUNDAY MORNING.
TEMPORARY IFR OR LIFR VIS CAN BE EXPECTED WITH ANY
THUNDERSTORMS...BUT PREVAILING CONDITIONS SHOULD REMAIN MVFR TO
VFR.
SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER
GUSTS...ESPECIALLY NEAR THUNDERSTORMS.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
627 PM CDT SAT MAY 16 2015
.UPDATE...AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 311 PM CDT SAT MAY 16 2015/
POPCORN TYPE SHOWERS AND THUNDERSTORMS ARE OCCURRING ACROSS THE
MIDSOUTH AND SURROUNDING AREAS. LATEST HRRR SHOWS THIS ACTIVITY
CONTINUING THROUGH AROUND 7-8 PM. THEREAFTER...ACTIVITY WILL
DISSIPATE FROM THE LOSS OF DAYTIME HEATING. EXPECT THE REMAINDER
OF THE NIGHT TO BE TRANQUIL. WILL LEAVE 30 POPS IN CASE A STRAY
SHOWER OR THUNDERSTORM DEVELOPS. LOWS WILL BE IN THE MID TO UPPER
60S.
A SEVERE LINE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP
THIS EVENING ACROSS OKLAHOMA...KANSAS...AND TEXAS. MODELS HAVE
BEEN PRETTY CONSISTENT WITH BRINGING THE REMNANTS OF THIS LINE
INTO EASTERN ARKANSAS AROUND SUNRISE. STILL EXPECT THE LINE TO BE
IN THE DYING PHASES AS IT MOVES IN. THE LINE WILL FALL APART AS IT
REACHES THE MS RIVER DURING THE MORNING. HOWEVER...REDEVELOPMENT
ALONG LEFTOVER BOUNDARIES WILL BE POSSIBLE ALONG AND EAST OF THE
MISSISSIPPI RIVER FROM MID-MORNING ON SUNDAY INTO THE AFTERNOON
HOURS.
EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DIE OUT AGAIN BY 7PM
SUNDAY EVENING. NEW DEVELOPMENT MAY OCCUR ALONG AND WEST OF THE
MISSISSIPPI RIVER DURING THE LATE EVENING TO OVERNIGHT HOURS AS A
SHORTWAVE MOVES INTO THE REGION. THIS ACTIVITY WILL BLOSSOM OVER
THE CWA INTO MONDAY.
THE COLD FRONT IS STILL EXPECTED TO MOVE INTO THE AREA MONDAY
NIGHT INTO TUESDAY. SCATTERED CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL CONTINUE ALONG AND AHEAD OF THE FRONT.
THE ECMWF AND GFS DIFFER ON HOW FAR SOUTH THE FRONT WILL PROGRESS.
IF THE ECMWF IS CORRECT...TUESDAY NIGHT MAY BE THE ONLY DRY PERIOD
BEFORE THE FRONT MOVES BACK NORTH AS A WARM FRONT. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL OCCUR ALONG AND AHEAD OF THE WARM
FRONT. THE FRONT WILL RETURN SOUTHWARD AS A COLD FRONT ON
THURSDAY. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL LIKELY OCCUR
ON THURSDAY.
HIGH PRESSURE WILL THEN BUILD INTO THE AREA ON FRIDAY.
&&
.AVIATION...00Z TAFS
SCATTERED SHRA AND TSRAS WILL DIMINISH IN BOTH INTENSITY AND
COVERAGE LATE THIS AFTERNOON AND OVERNIGHT. THE CHANCE FOR
ADDITIONAL ON STATION THUNDER LOOKS LOW AT JBR AND MEM...AND
SHOULD END IN THE NEXT HOUR OR TWO AT MKL AND TUP. QUIET
OVERNIGHT THEN LOW CLOUDS SHOULD REDEVELOP LATER TONIGHT INTO
EARLY SUNDAY...ESPECIALLY AT KJBR AND KTUP. A WEAKENING LINE OF
SHRAS AND TSRAS WILL BE PUSHING INTO THE MIDSOUTH SUNDAY MORNING.
TEMPORARY IFR OR LIFR VIS CAN BE EXPECTED WITH ANY
THUNDERSTORMS...BUT PREVAILING CONDITIONS SHOULD REMAIN MVFR TO
VFR.
SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER
GUSTS...ESPECIALLY NEAR THUNDERSTORMS.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
103 PM CDT FRI MAY 15 2015
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 1046 AM CDT FRI MAY 15 2015/
UPDATE...
LATEST RADAR SHOWS AN AREA OF SHOWERS AND THUNDERSTORMS GETTING
READY TO PUSH INTO PORTIONS OF NORTHEAST ARKANSAS. MEANWHILE...A
FEW SHOWERS HAVE BEEN DEVELOPING OVER NORTHEAST MISSISSIPPI AND
PORTIONS OF WEST TENNESSEE NEAR THE TENNESSEE RIVER OVER THE PAST
HOUR. LATEST HRRR SHOWS SHOWER AND THUNDERSTORM DEVELOPMENT WILL
EXPLODE OVER THE MIDSOUTH BY 1-2 PM AS A SHORTWAVE MOVES INTO THE
AREA. CURRENT POPS OF 60 LOOK GOOD AS WELL AS THE REST OF THE
FORECAST. NO UPDATES ARE EXPECTED.
KRM
DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
&&
.AVIATION...
12Z TAF CYCLE
MOIST AND UNSTABLE AIRMASS PREVAILS ACROSS THE REGION. GOOD
SURFACE HEATING WILL RESULT IN SCATTERED TO NUMEROUS SHRAS AND
TSRAS ACROSS MUCH OF THE AREA THIS AFTERNOON. EXPECT ACTIVITY TO
DIMINISH WITH LOSS OF HEATING THIS EVENING. ANOTHER ROUND OF
SHRAS/TSRAS IS POSSIBLE LATER TONIGHT AND EARLY SATURDAY AS A
DISTURBANCE...NOW LOCATED OVER TEXAS...MOVES NORTHEAST OVER THE
AREA. TIMING OF SHRA/TSRAS IS DIFFICULT AT BEST AND CONFIDENCE
BEYOND 6 HRS IS LOW. EXPECT A PERIOD OF LOW CLOUDS EARLY SATURDAY
MORNING.
SOUTH WINDS AROUND 10 KTS THROUGH THE PERIOD...SLIGHTLY LESS
OVERNIGHT.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1046 AM CDT FRI MAY 15 2015
.UPDATE...
LATEST RADAR SHOWS AN AREA OF SHOWERS AND THUNDERSTORMS GETTING
READY TO PUSH INTO PORTIONS OF NORTHEAST ARKANSAS. MEANWHILE...A
FEW SHOWERS HAVE BEEN DEVELOPING OVER NORTHEAST MISSISSIPPI AND
PORTIONS OF WEST TENNESSEE NEAR THE TENNESSEE RIVER OVER THE PAST
HOUR. LATEST HRRR SHOWS SHOWER AND THUNDERSTORM DEVELOPMENT WILL
EXPLODE OVER THE MIDSOUTH BY 1-2 PM AS A SHORTWAVE MOVES INTO THE
AREA. CURRENT POPS OF 60 LOOK GOOD AS WELL AS THE REST OF THE
FORECAST. NO UPDATES ARE EXPECTED.
KRM
&&
.DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
&&
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE EARLY MORNING
BEFORE SHOWERS AND THUNDERSTORMS DEVELOP ACROSS ALL TERMINALS.
SOMEWHAT DIFFICULT TO TIME THIS ACTIVITY AS SOME UNCERTAINTY STILL
EXISTS BUT DO EXPECT ISOLATED TO SCATTERED TSTORMS TO MOVE INTO
ALL TERMINALS BY 16-18Z. PRECIPITATION WILL LAST THROUGH MUCH OF
THE NEXT 24 HOURS WITH SHOWERS CONTINUING OFF AND ON THROUGH
FRIDAY NIGHT. CIGS MAY LOWER INTO THE MVFR CATEGORY EARLY SATURDAY
MORNING.
TVT
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
617 AM CDT FRI MAY 15 2015
.UPDATE...
UPDATED AVIATION DISCUSSION FOR 12Z TAFS...
&&
.PREV DISCUSSION... /ISSUED 425 AM CDT FRI MAY 15 2015/
DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE EARLY MORNING
BEFORE SHOWERS AND THUNDERSTORMS DEVELOP ACROSS ALL TERMINALS.
SOMEWHAT DIFFICULT TO TIME THIS ACTIVITY AS SOME UNCERTAINTY STILL
EXISTS BUT DO EXPECT ISOLATED TO SCATTERED TSTORMS TO MOVE INTO
ALL TERMINALS BY 16-18Z. PRECIPITATION WILL LAST THROUGH MUCH OF
THE NEXT 24 HOURS WITH SHOWERS CONTINUING OFF AND ON THROUGH
FRIDAY NIGHT. CIGS MAY LOWER INTO THE MVFR CATEGORY EARLY SATURDAY
MORNING.
TVT
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
425 AM CDT FRI MAY 15 2015
.DISCUSSION...
EARLY THIS MORNING...TRANQUIL WEATHER WAS BEING OBSERVED ACROSS THE
MIDSOUTH. HIGH LEVEL CLOUDS WERE INCREASING ACROSS THE REGION WITH A
LIGHT SOUTHEAST WIND AND MILD TEMPERATURES. THE BENIGN WEATHER WILL
COME TO AN END TODAY AS A WET WEATHER PATTERN SETS UP ACROSS THE
MIDSOUTH AND CONTINUES THROUGH MONDAY. RAISED THE POPS SOME DURING
MUCH OF THIS PERIOD. UPPER LEVEL DISTURBANCES AND DEVELOPMENT OF
MESOSCALE CONVECTIVE SYSTEMS THAT COULD AFFECT PORTIONS OF THE REGION
POSSIBLY TONIGHT INTO THE WEEKEND ARE DIFFICULT TO PINPOINT.
FOR TODAY...A WARM FRONT WILL LIFT NORTH OF THE MIDSOUTH WITH
MOIST AND UNSTABLE AIR SPREADING ACROSS THE AREA IN A SOUTHERLY WIND
FLOW. PRECIPITABLE WATER VALUES WILL CLIMB TO BETWEEN 1.7 AND 2.0
INCHES WHILE SURFACE DEW POINTS CLIMB THROUGH THE 60S. SURFACE BASED
CAPE IS FORECAST TO INCREASE TO BETWEEN 1500 AND 2500 J/KG...ALTHOUGH
MID LEVEL LAPSE RATES WILL BE WEAK. THE HRRR AND OTHER MODELS
INDICATE NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MOVING INTO OR
DEVELOPING ACROSS THE REGION THIS MORNING AND CONTINUING INTO
AFTERNOON. RAISED THE POPS TO LIKELY FOR TODAY. SOUTHWEST FLOW
ALOFT WILL OCCUR ACROSS THE AREA WITH EMBEDDED WEAK UPPER LEVEL
DISTURBANCES AIDING IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL REMAIN MILD TO WARM TODAY AND OVER THE WEEKEND
TEMPERED SOME BY CLOUDS AND RAIN.
ON SATURDAY...AN UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN
PLAINS WITH AN UPPER LEVEL RIDGE OVER THE SOUTHEASTERN UNITED
STATES. A CONTINUED SOUTHERLY FLOW OF MOIST AND UNSTABLE AIR INTO THE
MIDSOUTH WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS. FLOODING
MAY BECOME A PROBLEM IN SOME LOCATIONS OVER THE WEEKEND FROM LOCALLY
HEAVY RAINFALL. MID LEVEL LAPSE RATES WILL BEGIN TO INCREASE SOME
OVER THE REGION LEADING TO THE POSSIBILITY OF A FEW STRONG
THUNDERSTORMS BY SATURDAY AFTERNOON WITH STRONG GUSTY WINDS AND SMALL
HAIL.
SATURDAY NIGHT...THE MORE ORGANIZED CONVECTION WILL BE LOCATED TO
OUR WEST ALONG A COLD FRONT ASSOCIATED WITH AN UPPER LEVEL TROUGH
PUSHING THROUGH THE CENTRAL PLAINS. SOME OF THIS CONVECTION MAY
PUSH INTO NORTHEAST AR AND THE MO BOOTHEEL BY LATE SATURDAY NIGHT...
BUT CONTINUING THE TREND THIS SPRING THE MAJORITY OF THE UPPER LEVEL
SUPPORT WILL PUSH TO THE NORTHEAST AS THE UPPER RIDGE REMAINS
STRONG ALONG THE SOUTHEASTERN UNITED STATES COAST. NEVERTHELESS...
THE UPPER LEVEL TROUGHING MAY EXTEND FAR ENOUGH SOUTH ALONG WITH AN
ACCOMPANYING STRONG WIND FIELD TO SUPPORT A MARGINAL RISK OF SEVERE
THUNDERSTORMS LATE SATURDAY NIGHT OR SUNDAY MAINLY FROM NORTHEAST AR
AND THE MO BOOTHEEL INTO PORTIONS OF NORTHWEST TN. ATTM...WILL
CONTINUE WITH MENTION OF STRONG THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK WITH THE BETTER CHANCE OF SEVERE STORMS JUST TO THE
NORTH OF OUR AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR SUNDAY AS
THE COLD FRONT MOVES TOWARD THE MIDSOUTH FROM THE NORTHWEST. THE
FRONT WILL SLOW AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW ACROSS
THE MIDSOUTH AND PUSHES CLOSER TO THE UPPER LEVEL RIDGE CENTERED OVER
THE SOUTHEASTERN UNITED STATES. THE FRONT WILL GRADUALLY PUSH THROUGH
THE MIDSOUTH MONDAY WITH NUMEROUS SHOWERS AND THUNDERSTORMS.
DRY AND A LITTLE COOLER AIR WILL FOLLOW THE FRONT TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA FROM THE NORTH. OVERRUNNING SHOWERS
WILL DEVELOP FROM THE WEST WEDNESDAY AND SPREAD ACROSS THE AREA
WEDNESDAY NIGHT AND THURSDAY. TEMPERATURES WILL REMAIN MILD.
JCL
&&
.AVIATION...
06Z TAF CYCLE
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE PERIOD. A WARM
FRONT WILL MOVE NORTHEAST ACROSS SITES ON FRIDAY WITH VCTS
OCCURING AT ALL SITES MAINLY AFTER 15/15-16Z. CHANCES FOR
VCSH/VCTS ARE EXPECTED TO PERSIST THROUGH THE END OF THE PERIOD. LIGHT
WINDS WILL INCREASE TO SOUTH WINDS BETWEEN 6-10 KTS ON FRIDAY AND
BECOME LIGHT TOWARDS 16/00Z.
04
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
930 PM CDT SAT MAY 16 2015
.DISCUSSION...
THE 00Z CRP SOUNDING SHOWED A SMALL CAP DEVELOPING OVER SE TX.
THERE WERE ISOLATED SHOWERS MOVING INLAND JUST EAST OF CHAMBERS
AND LIBERTY COUNTIES AT 920 PM. EXPECT THESE TO CONTINUE MOVING
INLAND AND STAY MAINLY EAST OF THE FORECAST AREA.
THE STORMS THAT WERE LOCATED ALONG THE DRY LINE OUT IN WEST AND
NORTH TEXAS SHOULD CONTINUE TO MOVE EASTWARD THROUGHOUT THE NIGHT.
THE 01Z RAP13 AND HRRR PLUS THE 00Z NAM12 WERE ALL PUSHING THE
AREA OF STORMS INTO THE FAR NORTHWESTERN COUNTIES BY MID MORNING
SUNDAY.
LOWERED THE POPS OVER THE NORTHERN COUNTIES TO 20 PERCENT FOR
TONIGHT. ALSO ADDED THE MENTION OF LESS THAN 20 PERCENT CHANCE FOR
SHOWERS OVER THE FAR EASTERN PORTIONS OF CHAMBERS...LIBERTY... AND
POLK COUNTIES. OTHERWISE...THE CURRENT FORECAST IS ON TRACK.
40
&&
.PREV DISCUSSION... /ISSUED 656 PM CDT SAT MAY 16 2015/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION...
AVIATION...
SOUTHERLY WINDS SHOULD REMAIN AROUND 8-12KTS TONIGHT AND THEN
INCREASE AGAIN TOMORROW TO 10-15KTS WITH GUSTS ABOVE 20KTS. CIGS
SHOULD DROP TO MVFR FOR THE MORNING HOURS. KCLL/KUTS/KCXO MAY SEE
A FEW HOURS OF IFR CIGS IN THE MORNING LIKE THIS MORNING. WILL
NEED TO MONITOR CONVECTION COMING OUT OF C TX TO SEE IF IT WILL
IMPACT TERMINALS IN THE MORNING WITH OUTFLOW BOUNDARY POSSIBLY
BEING A FOCUS FOR CONVECTION IN THE AFTERNOON. FOR NOW WILL GO
WITH VCSH AS CAPPING WILL STILL BE STRONG AND DAY TIME HEATING MAY
NOT BE ENOUGH FOR STORMS TO INITIATE.
39
PREV DISCUSSION... /ISSUED 305 PM CDT SAT MAY 16 2015/
DISCUSSION...
DAYTIME HEATING IS WORKING THE MAGIC THIS AFTERNOON WITH SCATTERED
SHOWERS AND THUNDERSTORMS NORTH OF THE 59 CORRIDOR. STORMS HAVE
BEEN SMALL AND NOT VERY IMPRESSIVE WITH WIND GUSTS OF 25 KNOTS /
VIL 25-40G/KG /STORM MOTIONS OF 23 KNOTS AND RAINFALL RATES OF
25-.75"/HOUR THANKS TO FAIRLY QUICK MOTION. THOUGH THE INSTABILITY
DOES CONTINUE TO INCREASE THE AMDAR SOUNDINGS SHOW THAT WITH PEAK
HEATING CAPE VALUES LIMITED TO 2100-2700J/KG WITH LITTLE
DIRECTIONAL SHEAR. EXPECT THAT REDEVELOPMENT WILL OCCUR THROUGH
THE REMAINING AFTERNOON HOURS PROGRESSIVELY FURTHER NORTH...THEN
WANE DURING THE EARLY EVENING HOURS. A FEW MODELS HIGHLIGHT
DEVELOPMENT WELL DOWN THE DRYLINE IN WEST TEXAS BETWEEN MAF/SJT.
IF THIS OCCURS THEN WILL NEED TO KEEP AN EYE ON THE TAIL- DRAGGERS
AS THEY MAY GET CLOSE TO THE NW CWA AFTER MIDNIGHT. HEAVY RAIN
THREAT LOOKS LOW HERE BUT NORTHWEST OF THE AREA THE THREAT SHOULD
INCREASE WHERE STORMS LINE UP AND TRAIN AS LLJ INTENSIFIES WITH
STORMS GOING MUCH OF THE NIGHT LIKELY JUST TO OUR NORTHWEST.
OVERNIGHT EXPECT ST DECK TO RETURN THE AREA AND SSE FLOW TO
CONTINUE ALBEIT SOMEWHAT LESS FORCEFULLY INLAND SO TEMPERATURES
SHOULD FALL SLOWLY GIVEN THE CLOUD COVER/WINDS.
UPPER RIDGING WILL CONTINUE TO PLAY A LARGER PART IN OUR DAILY
RAIN CHANCES AS RIDGING BUILDS INTO THE AREA 588-590DM 500MB
HEIGHTS COVER MUCH OF THE REGION SUNDAY AND EARLY MONDAY. THIS
SHOULD LEAD TO WARMER CONDITIONS AND A LITTLE MORE CAPPING. THEN
LATE MONDAY AND TUESDAY RIDGE FLATTENS AND RAIN CHANCES SHOULD
INCREASE SLIGHTLY FOR THE NORTHERN HALF OF THE AREA AS STORM TRACK
SHIFTS SLIGHTLY FURTHER SOUTH AND EAST. HIGHEST RAIN CHANCE THIS
WEEK LOOK TO BE OVER THE NORTHEAST COUNTIES ON MONDAY AND TUESDAY
AFTERNOON. FRONTAL BOUNDARY SLIPS SOUTH INTO THE NORTHEAST
PORTIONS TX/NW LA AND THIS COULD BECOME A FOCUS FOR STORMS.
HEAVIER RAINS IN THESE NORTHERN AREAS A THREAT MONDAY AND TUESDAY.
WEDNESDAY THE RIDGING RETURNS AND RAIN CHANCES AGAIN TAPER OFF.
NEXT TROUGH DROPS INTO THE DESERT SW FRIDAY/SATURDAY WHICH MAY SET
THE STAGE FOR SLIGHTLY HIGHER RAIN CHANCES IN OUR WESTERN ZONES
BUT EXTENDED GUIDANCE SHOWING THE RIDGING OVER THE GULF POSSIBLY
EXERTING ENOUGH INFLUENCE TO LIMIT RAIN CHANCES OVER AT LEAST THE
SOUTHEASTERN HALF OF THE AREA.
TEMPERATURES SHOULD RUN 2 TO 4 DEGREES WARMER THAN NORMAL DURING
THE DAY AND 4 TO 9 DEGREES WARMER ON MINS WITH THE PERSISTENT
MOIST GULF RETURN.
45
MARINE...
AS A STRONG STORM SYSTEM DEEPENS OVER THE CENTRAL PLAINS...
A TIGHTENING PRESSURE GRADIENT WILL HELP KEEP ELEVATED WINDS
AND SEAS ACROSS OUR COASTAL WATERS THROUGH SUNDAY. CAUTION FLAGS
ARE IN EFFECT...AND ADVISORIES MIGHT BE NEEDED. WINDS AND SEAS
ARE STILL EXPECTED TO DECREASE BEGINNING ON MONDAY...AND MAINLY
MODERATE ONSHORE WINDS ARE ANTICIPATED FOR MUCH OF THE WEEK.
42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 87 74 87 72 / 20 30 20 30 20
HOUSTON (IAH) 77 88 75 88 73 / 20 20 20 30 10
GALVESTON (GLS) 78 85 79 85 76 / 10 20 20 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 AM CDT SUNDAY FOR
THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH SUNDAY EVENING FOR
THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA
SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
344 PM CDT FRI MAY 15 2015
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THE MAIN UPDATE WITH THE AFTERNOON PACKAGE WAS TO UPDATE THE
ONGOING FLASH FLOOD WATCH TO ENCOMPASS THE ENTIRE AREA. THE MAIN
THREAT FOR HEAVY RAINFALL NORTH OF INTERSTATE 10 WILL PRIMARILY BE
FROM THE SCATTERED... DAYTIME HEATING DRIVEN THUNDERSTORMS...
WHILE SOUTH OF INTERSTATE 10 WILL NEED TO BE CONCERNED WITH HEAVY
RAINFALL FROM THE EASTWARD MOVING MCS.
TWO DIFFERENT CONVECTIVE SITUATIONS UNFOLDING ACROSS THE REGION
THIS AFTERNOON. THE FIRST... SCATTERED THUNDERSTORMS ALONG AND
EAST OF THE INTERSTATE 45 CORRIDOR THAT HAVE DEVELOPED WHERE
ENOUGH CLOUD THINNING HAS OCCURRED FOR CONVECTIVE TEMPERATURES TO
BE REACHED. THE SECOND... A LINEAR MCS THAT HAS PROPAGATED ACROSS
CENTRAL TEXAS TODAY TOWARDS THE REGION. THE LEADING STRATIFORM
RAIN ASSOCIATED WITH THIS SYSTEM /AS OF 3 PM CDT/ EXTENDS FROM
COLLEGE STATION... TO HOUSTON... TO PALACIOS... AND WILL CONTINUE
TO OVERSPREAD THE REGION AS THE SYSTEM MOVES EAST. ACTIVITY AHEAD
OF THE WESTERNMOST SYSTEM WILL CONTINUE TO WANE WITH LOSS OF
DAYTIME HEATING... BUT THE MCS IS EXPECTED TO MAINTAIN ITSELF INTO
THE REGION WITH THE KHGX VAD WIND PROFILER SHOWING 25 TO 30 KNOTS
OF MOIST SOUTHERLY INFLOW AROUND 4 TO 5 KFT ABOVE THE GROUND
/ROUGHLY AROUND 850 MB/.
LATEST RAP GUIDANCE SHOWS THIS PERSISTING INTO THE EVENING HOURS
AS THE SHORTWAVE AIDING THIS ACTIVITY /AND LOCATED OVER CENTRAL
TEXAS PER WATER VAPOR IMAGERY/ SWINGS NORTH OF THE REGION. ANY
STORM THAT DEVELOPS THROUGH THE EVENING WILL BE CAPABLE OF HEAVY
RAINFALL WITH GPS MET ESTIMATED PRECIPITABLE WATER VALUES AROUND
1.7 INCHES THIS AFTERNOON THAT TREND IS EXPECTED TO CONTINUE. THE
SHORTWAVE LOOKS TO SWING NORTH OF THE REGION LATER TONIGHT
/BETWEEN 9 PM AND 12 AM CDT/... AND SUBSIDENCE BEHIND THIS FEATURE
WILL RESULT IN LOWER RAIN CHANCES OVERNIGHT FOR THE REGION.
THE BREAK IN THE RAIN CHANCES WILL BE SHORT-LIVED AS ANOTHER ROUND
OF DIURNALLY DRIVEN CONVECTION LOOKS TO BREAK OUT TOMORROW
AFTERNOON AS HIGH TEMPERATURES APPROACH THE MID 80S. SOUTHERLY LOW
LEVEL FLOW WILL MAINTAIN 1.5 TO 1.7 INCH PWATS ACROSS THE REGION
AND SIMILAR TO TODAY ANY STORM THAT DEVELOPS WILL BE CAPABLE OF
PRODUCING HEAVY RAINFALL. COVERAGE IS NOT ANTICIPATED TO BE AS
WIDESPREAD AS TODAY... ALTHOUGH ANY RESIDUAL BOUNDARIES LEFT OVER FROM
TODAY WILL SERVE AS A FOCUSING MECHANISM FOR STORM DEVELOPMENT.
SOME OF THESE STORMS MAY BRIEFLY BECOME STRONG WITH MUCAPE VALUES
APPROACHING 3000-4000 J/KG... BUT 0-6 KM BULK SHEAR VALUES
GENERALLY AROUND 20 KNOTS WILL DO LITTLE TO PROMOTE STORM
ORGANIZATION. BETTER CHANCES FOR STRONG STORMS FOR THE NORTHWEST
ZONES /COLLEGE STATION FORECAST SOUNDINGS SHOWING SOME STRONGER
SHEAR AROUND 30 KNOTS/.
BY SATURDAY NIGHT... AN UPPER LOW SWINGING ACROSS THE TEXAS AND
OKLAHOMA PANHANDLES INTO THE CENTRAL PLAINS WILL SEND ANOTHER LINE
OF STORMS TOWARDS THE AREA EARLY SUNDAY MORNING AND ANOTHER PERIOD
OF HEAVY RAIN LOOKS TO BE POSSIBLE IN THE EXTENDED.
HUFFMAN
&&
.EXTENDED /SUNDAY THROUGH FRIDAY/...
THUNDERSTORMS MOVING ACROSS THE AREA ON SUNDAY WILL PROVIDE
ANOTHER SHOT AT HEAVY RAINFALL FOR SOUTHEAST TEXAS AS AN UPPER
LEVEL LOW SWINGS NORTH OF THE REGION... WITH ANOTHER ROUND
POSSIBLE INTO MONDAY AS A WEAK COLD FRONT LOOKS TO STALL NEAR THE
REGION. CONTINUING TO MONITOR THE SUNDAY/MONDAY TIMEFRAME FOR
POTENTIAL IMPACTS TO SOUTHEAST TEXAS AS SOILS ARE STILL SATURATED
AND FLOODING CONCERNS ARE POSSIBLE. SOUTHWEST FLOW ALOFT WILL
PERSIST THROUGH MID-WEEK BEFORE A BUILDING RIDGE USHERS IN A
PERIOD OF DRIER WEATHER FOR THE REGION. RIDGING OVERHEAD WILL
ALLOW TEMPERATURES TO SLOWLY WARM ABOVE SEASONAL NORMALS... WITH
LONG TERM GUIDANCE HINTING AT SOME OF THE FIRST 90 DEGREE DAY
WE/VE SEEN THIS YEAR AT THE END OF NEXT WEEK. WIDESPREAD RAIN
CHANCES BEGIN INCREASING NEXT WEEKEND AS ANOTHER UPPER LOW
APPROACHES FROM THE WEST.
HUFFMAN
&&
.MARINE...
A SOLID LINE OF SHOWERS AND THUNDERSTORMS CAPABLE OF PRODUCING STRONG
WINDS AND HEAVY RAINFALL AND FREQUENT LIGHTNING IS EXPECTED TO MOVE
ACROSS THE AREA THIS AFTERNOON AND THIS EVENING. EXPECT STRONGER
WINDS AND HIGHER SEAS IN AND NEAR THE STORMS. A TIGHTENING PRESSURE
GRADIENT ANTICIPATED OVER THE WEEKEND IS EXPECTED TO BRING INCREASING
WINDS AND BUILDING SEAS TO THE AREA OVER THE WEEKEND. CAUTION FLAGS
ARE IN EFFECT BEGINNING TONIGHT ACROSS THE OFFSHORE WATERS...AND
ADVISORIES MIGHT BE NEEDED OVER THE WEEKEND. CLOSER TO THE COAST...
THE STRENGTHENING WINDS AND BUILDING SEAS MIGHT REACH CAUTION LEVELS.
LOWERING WINDS AND SEAS ARE EXPECTED NEXT WEEK. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 71 85 73 86 73 / 20 30 20 50 50
HOUSTON (IAH) 73 87 75 86 74 / 40 30 20 40 30
GALVESTON (GLS) 76 82 77 83 76 / 40 20 20 30 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
HOUSTON...JACKSON...LIBERTY...MADISON...MATAGORDA...
MONTGOMERY...POLK...SAN JACINTO...TRINITY...WALKER...
WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION FROM MIDNIGHT CDT TONIGHT
THROUGH LATE SATURDAY NIGHT FOR THE FOLLOWING ZONES: WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...14
AVIATION/MARINE...42
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
114 PM CDT FRI MAY 15 2015
.AVIATION... /18Z TAF UPDATE/
A SLOW DEPARTURE OF THE MORNING MCS WILL CONTINUE TO PRODUCE MINOR
IMPACTS OVER I-35 TERMINALS OVER THE NEXT HOUR OR TWO. BY 20Z ALL
TAF SITES ARE FORECAST TO SEE VFR SKIES AS SUBSIDENCE REPLACES THE
DEPARTING STORM COMPLEX. SOME BRIEF SHIFTINESS AND WEAKENING OF
WINDS ARE EXPECTED IN THE MID AFTERNOON AROUND SAN ANTONIO...BUT
THE PRESSURE GRADIENT SHOULD OTHERWISE TIGHTEN AGAIN FOR A
MODERATE SOUTHEAST BREEZE ACROSS THE AREA. WILL SHOW A CONTINUED
AGGRESSIVE RETURN OF LOW CLOUDS IN THE EVENING AND PATCHY FOG AND
CLOUDS TO DROP CONDITIONS TO IFR FOR MOST AREAS LATE
TONIGHT. AT AROUND SAN ANTONIO WILL SHOW LIFR CIGS TOWARD DAYBREAK AS
SURFACE CONDITIONS CONTINUE TO BE EXTRA MOIST WITH WINDS PROBABLE
TO DECOUPLE MORE IN THAT AREA THAN THE TAF SITES TO THE NORTH AND
WEST. LIGHT SHRA COULD DEVELOP WITH THE LOW LEVEL JET...BUT WILL
KEEP OUT THE POSSIBILITY OF THUNDERSTORMS FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 1222 PM CDT FRI MAY 15 2015/
UPDATE...
BASED ON RADAR TRENDS AND THE LATEST HRRR GUIDANCE...WE HAVE
EXPANDED THE FLASH FLOOD WATCH TO COVER THE COASTAL PLAINS AND
HIGHWAY 77 CORRIDOR. THE WATCH WILL NOW BE IN EFFECT UNTIL 5 PM
CDT.
PREV DISCUSSION... /ISSUED 930 AM CDT FRI MAY 15 2015/
UPDATE...
WE HAVE UPDATED THE FORECAST TO INCREASE RAINFALL CHANCES FOR
AREAS ALONG AND EAST OF I-35 THROUGH THIS MORNING. BACK-BUILDING
THUNDERSTORMS NOTED ACROSS THE RIO GRANDE PLAINS...BUT THIS
ACTIVITY SHOULD SLOWLY TRANSLATE EAST TODAY. WATER VAPOR SATELLITE
LOOP SHOWS MID-LEVEL DRYING COMING IN FROM THE WEST. GIVEN
PERSISTENT SOUTHEASTERLY FLOW AND DAYTIME HEATING...AM CONCERNED
ABOUT ANOTHER ROUND OF CONVECTION DEVELOPING TO OUR WEST THIS
AFTERNOON. WE/LL CONTINUE TO MONITOR CAREFULLY AND AWAIT 12Z MODEL
DATA.
PREV DISCUSSION... /ISSUED 657 AM CDT FRI MAY 15 2015/
AVIATION... /12Z TAF UPDATE/
SLOW MOVING COMPLEX WILL BRING A ROUND OF TSRA THROUGH THE I-35
TERMINALS THROUGH 14-16Z WITH A WEAK MCV TO BRING IMPROVEMENTS
TO POSSIBLY VFR SKIES AT SAT/SSF BY 14Z. IMPROVEMENTS WILL BE
SLOWER TO COME BY AT AUS WHERE ADDITIONAL TRAILING CONVECTION
EXTENDS DEEP INTO THE HILL COUNTRY. NO CONVECTION IS ACCOUNTED FOR
IN THE DRT TAF AS ONLY SOME ISOLATED ACTIVITY IS EXPECTED TO
FORM...WITH NO GOOD MODEL SIGNALS ON TIMING. SATURATED LOW LEVELS
SHOULD LEAD TO QUICK LOW CLOUD FORMATION THIS EVENING WITH MANY
AREAS FALLING INTO IFR OR LOWER LEVELS WITH BOTH CIGS AND PATCHY
FOG AFTER MIDNIGHT.
PREV DISCUSSION... /ISSUED 546 AM CDT FRI MAY 15 2015/
UPDATE...
THE RAINS HAVE ENDED ACROSS THE EDWARDS PLATEAU. THERE MAY BE SOME
LIGHT RAIN IN THE NEXT FEW HOURS. HOWEVER...FLASH FLOODING IS NO
LONGER EXPECTED AND THE FLASH FLOOD WATCH FOR EDWARDS...REAL AND
VAL VERDE COUNTIES HAS BEEN CANCELLED. ALSO...HAVE TRIMMED DOWN
EXPECTED RAINFALL AMOUNTS IN THE REMAINING WATCH AREA TO 1 TO 3
INCHES WITH ISOLATED ADDITIONAL 4 INCHES SINCE THE MCS HAS BECOME
MORE PROGRESSIVE.
PREV DISCUSSION... /ISSUED 402 AM CDT FRI MAY 15 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...
AN OUTFLOW BOUNDARY DEVELOPED AN MCS ACROSS THE RIO GRANDE PLAINS
THURSDAY EVENING. AN UPPER LEVEL SHORTWAVE BRINGING MOISTURE FROM
THE EASTERN PACIFIC AND STRONG DIFFLUENCE ALOFT ALONG WITH A
SOUTHEASTERLY LOWER LEVEL FLOW BRINGING MOISTURE FROM THE GULF OF
MEXICO MAINTAINED THE MCS OVERNIGHT. RADAR TRENDS SHOW THE MCS
STARTING TO MOVE EAST. EXPECT IT TO MAKE IT TO THE I-37 CORRIDOR
THIS MORNING BEFORE IT WEAKENS. THE I-37 CORRIDOR AREA HAD VERY
HEAVY RAINS THURSDAY AFTERNOON INTO EVENING MAKING THE SOILS EVEN
MORE SATURATED FROM RECENT RAINS. EXPECT RAINFALL AMOUNTS OF 2 TO
4 INCHES WITH ISOLATED ADDITIONAL AMOUNTS UP TO 6 INCHES POSSIBLE.
AS A RESULT...HAVE EXPANDED THE FLASH FLOOD WATCH TO INCLUDE SAN
ANTONIO AND BEXAR COUNTY SOUTHEAST TO ATASCOSA...KARNES AND WILSON
COUNTIES. EXPECT THE MCS TO WEAKEN BY MIDDAY WITH THE WATCH
EXPIRING AT NOON. STRONG TO SEVERE STORMS ARE ALSO POSSIBLE WITH
THE MCS. THE UPPER LEVEL SHORTWAVE WILL LINGER OVER SOUTH CENTRAL
TEXAS INTO THE AFTERNOON AND HAVE MAINTAINED HIGH POPS THROUGH
TODAY. THE SHORTWAVE MOVES TO THE NORTHEAST WHILE THE AIRMASS
STABILIZES TONIGHT. HAVE RETAINED SLIGHT CHANCE POPS AS AMPLE
MOISTURE LINGERS. AN UPPER LEVEL TROUGH CURRENTLY CENTERED JUST
OFF POINT CONCEPTION ALONG THE SOUTHERN CALIFORNIA COAST WILL MOVE
ACROSS THE DESERT SOUTHWEST INTO THE ROCKIES ON SATURDAY. UPWARD
FORCING INCREASES LEADING TO CHANCE POPS WITH SOME STRONG STORMS
AND LOCALLY HEAVY RAINS POSSIBLE.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE UPPER LEVEL TROUGH MOVES NORTHEAST ACROSS THE PLAINS SATURDAY
NIGHT INTO SUNDAY WHILE ANOTHER UPPER LEVEL TROUGH DROPS SOUTH OFF
THE WEST COAST. THE UPPER LEVEL JET BECOMES MORE ACTIVE WITH THE
DRYLINE MOVING TO THE EAST. POPS WILL INCREASE AGAIN SATURDAY
NIGHT IN THE NORTH AND ALL AREAS ON SUNDAY. STRONG TO SEVERE
STORMS AND LOCALLY HEAVY RAINS ARE POSSIBLE. SOME FLOODING MAY
RESULT FROM STORMS TRAINING OVER THE SAME AREAS. THE HIGH POPS
CONTINUE INTO MONDAY WHEN A COLD FRONT MAY MOVE INTO CENTRAL
TEXAS PROVIDING ADDITIONAL UPWARD FORCING. THIS NEXT WEST COAST
UPPER LEVEL TROUGH MOVES INLAND ON MONDAY AND THEN INTO THE
NORTHERN ROCKIES BY WEDNESDAY...REPLACED BY YET ANOTHER UPPER
LEVEL TROUGH THAT APPROACHES THE WEST COAST THAT WILL MOVE INTO
THE SOUTHWESTERN STATES ON FRIDAY. WILL MAINTAIN POPS FOR ALL OF
NEXT WEEK DUE TO THESE FEATURES AND OTHER WEAKER DISTURBANCES IN
THE SOUTHWESTERLY FLOW ALOFT. LOOKING AHEAD TO THE MEMORIAL DAY
WEEKEND...THE MODELS INDICATE AT LEAST SLIGHT CHANCE POPS AS THE
PATTERN CONTINUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 82 71 85 72 83 / 80 20 30 50 60
AUSTIN BERGSTROM INTL AIRPORT 82 71 84 73 84 / 80 20 30 40 60
NEW BRAUNFELS MUNI AIRPORT 82 70 84 72 83 / 80 20 30 30 60
BURNET MUNI AIRPORT 80 69 82 70 81 / 60 20 40 70 70
DEL RIO INTL AIRPORT 83 71 87 69 85 / 30 20 30 50 40
GEORGETOWN MUNI AIRPORT 80 70 83 71 82 / 70 20 40 60 70
HONDO MUNI AIRPORT 82 71 85 72 83 / 80 20 30 40 60
SAN MARCOS MUNI AIRPORT 81 71 85 72 83 / 80 20 30 30 60
LA GRANGE - FAYETTE REGIONAL 82 72 85 74 85 / 80 20 30 20 40
SAN ANTONIO INTL AIRPORT 82 71 84 72 83 / 80 20 30 40 60
STINSON MUNI AIRPORT 83 72 86 73 84 / 80 20 30 40 50
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 5 PM CDT THIS AFTERNOON FOR THE FOLLOWING
COUNTIES: DE WITT...FAYETTE...GONZALES...KARNES...LAVACA...LEE...
WILSON.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...24
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1222 PM CDT FRI MAY 15 2015
.UPDATE...
BASED ON RADAR TRENDS AND THE LATEST HRRR GUIDANCE...WE HAVE
EXPANDED THE FLASH FLOOD WATCH TO COVER THE COASTAL PLAINS AND
HIGHWAY 77 CORRIDOR. THE WATCH WILL NOW BE IN EFFECT UNTIL 5 PM
CDT.
&&
.PREV DISCUSSION... /ISSUED 930 AM CDT FRI MAY 15 2015/
UPDATE...
WE HAVE UPDATED THE FORECAST TO INCREASE RAINFALL CHANCES FOR
AREAS ALONG AND EAST OF I-35 THROUGH THIS MORNING. BACK-BUILDING
THUNDERSTORMS NOTED ACROSS THE RIO GRANDE PLAINS...BUT THIS
ACTIVITY SHOULD SLOWLY TRANSLATE EAST TODAY. WATER VAPOR SATELLITE
LOOP SHOWS MID-LEVEL DRYING COMING IN FROM THE WEST. GIVEN
PERSISTENT SOUTHEASTERLY FLOW AND DAYTIME HEATING...AM CONCERNED
ABOUT ANOTHER ROUND OF CONVECTION DEVELOPING TO OUR WEST THIS
AFTERNOON. WE/LL CONTINUE TO MONITOR CAREFULLY AND AWAIT 12Z MODEL
DATA.
PREV DISCUSSION... /ISSUED 657 AM CDT FRI MAY 15 2015/
AVIATION... /12Z TAF UPDATE/
SLOW MOVING COMPLEX WILL BRING A ROUND OF TSRA THROUGH THE I-35
TERMINALS THROUGH 14-16Z WITH A WEAK MCV TO BRING IMPROVEMENTS
TO POSSIBLY VFR SKIES AT SAT/SSF BY 14Z. IMPROVEMENTS WILL BE
SLOWER TO COME BY AT AUS WHERE ADDITIONAL TRAILING CONVECTION
EXTENDS DEEP INTO THE HILL COUNTRY. NO CONVECTION IS ACCOUNTED FOR
IN THE DRT TAF AS ONLY SOME ISOLATED ACTIVITY IS EXPECTED TO
FORM...WITH NO GOOD MODEL SIGNALS ON TIMING. SATURATED LOW LEVELS
SHOULD LEAD TO QUICK LOW CLOUD FORMATION THIS EVENING WITH MANY
AREAS FALLING INTO IFR OR LOWER LEVELS WITH BOTH CIGS AND PATCHY
FOG AFTER MIDNIGHT.
PREV DISCUSSION... /ISSUED 546 AM CDT FRI MAY 15 2015/
UPDATE...
THE RAINS HAVE ENDED ACROSS THE EDWARDS PLATEAU. THERE MAY BE SOME
LIGHT RAIN IN THE NEXT FEW HOURS. HOWEVER...FLASH FLOODING IS NO
LONGER EXPECTED AND THE FLASH FLOOD WATCH FOR EDWARDS...REAL AND
VAL VERDE COUNTIES HAS BEEN CANCELLED. ALSO...HAVE TRIMMED DOWN
EXPECTED RAINFALL AMOUNTS IN THE REMAINING WATCH AREA TO 1 TO 3
INCHES WITH ISOLATED ADDITIONAL 4 INCHES SINCE THE MCS HAS BECOME
MORE PROGRESSIVE.
PREV DISCUSSION... /ISSUED 402 AM CDT FRI MAY 15 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...
AN OUTFLOW BOUNDARY DEVELOPED AN MCS ACROSS THE RIO GRANDE PLAINS
THURSDAY EVENING. AN UPPER LEVEL SHORTWAVE BRINGING MOISTURE FROM
THE EASTERN PACIFIC AND STRONG DIFFLUENCE ALOFT ALONG WITH A
SOUTHEASTERLY LOWER LEVEL FLOW BRINGING MOISTURE FROM THE GULF OF
MEXICO MAINTAINED THE MCS OVERNIGHT. RADAR TRENDS SHOW THE MCS
STARTING TO MOVE EAST. EXPECT IT TO MAKE IT TO THE I-37 CORRIDOR
THIS MORNING BEFORE IT WEAKENS. THE I-37 CORRIDOR AREA HAD VERY
HEAVY RAINS THURSDAY AFTERNOON INTO EVENING MAKING THE SOILS EVEN
MORE SATURATED FROM RECENT RAINS. EXPECT RAINFALL AMOUNTS OF 2 TO
4 INCHES WITH ISOLATED ADDITIONAL AMOUNTS UP TO 6 INCHES POSSIBLE.
AS A RESULT...HAVE EXPANDED THE FLASH FLOOD WATCH TO INCLUDE SAN
ANTONIO AND BEXAR COUNTY SOUTHEAST TO ATASCOSA...KARNES AND WILSON
COUNTIES. EXPECT THE MCS TO WEAKEN BY MIDDAY WITH THE WATCH
EXPIRING AT NOON. STRONG TO SEVERE STORMS ARE ALSO POSSIBLE WITH
THE MCS. THE UPPER LEVEL SHORTWAVE WILL LINGER OVER SOUTH CENTRAL
TEXAS INTO THE AFTERNOON AND HAVE MAINTAINED HIGH POPS THROUGH
TODAY. THE SHORTWAVE MOVES TO THE NORTHEAST WHILE THE AIRMASS
STABILIZES TONIGHT. HAVE RETAINED SLIGHT CHANCE POPS AS AMPLE
MOISTURE LINGERS. AN UPPER LEVEL TROUGH CURRENTLY CENTERED JUST
OFF POINT CONCEPTION ALONG THE SOUTHERN CALIFORNIA COAST WILL MOVE
ACROSS THE DESERT SOUTHWEST INTO THE ROCKIES ON SATURDAY. UPWARD
FORCING INCREASES LEADING TO CHANCE POPS WITH SOME STRONG STORMS
AND LOCALLY HEAVY RAINS POSSIBLE.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE UPPER LEVEL TROUGH MOVES NORTHEAST ACROSS THE PLAINS SATURDAY
NIGHT INTO SUNDAY WHILE ANOTHER UPPER LEVEL TROUGH DROPS SOUTH OFF
THE WEST COAST. THE UPPER LEVEL JET BECOMES MORE ACTIVE WITH THE
DRYLINE MOVING TO THE EAST. POPS WILL INCREASE AGAIN SATURDAY
NIGHT IN THE NORTH AND ALL AREAS ON SUNDAY. STRONG TO SEVERE
STORMS AND LOCALLY HEAVY RAINS ARE POSSIBLE. SOME FLOODING MAY
RESULT FROM STORMS TRAINING OVER THE SAME AREAS. THE HIGH POPS
CONTINUE INTO MONDAY WHEN A COLD FRONT MAY MOVE INTO CENTRAL
TEXAS PROVIDING ADDITIONAL UPWARD FORCING. THIS NEXT WEST COAST
UPPER LEVEL TROUGH MOVES INLAND ON MONDAY AND THEN INTO THE
NORTHERN ROCKIES BY WEDNESDAY...REPLACED BY YET ANOTHER UPPER
LEVEL TROUGH THAT APPROACHES THE WEST COAST THAT WILL MOVE INTO
THE SOUTHWESTERN STATES ON FRIDAY. WILL MAINTAIN POPS FOR ALL OF
NEXT WEEK DUE TO THESE FEATURES AND OTHER WEAKER DISTURBANCES IN
THE SOUTHWESTERLY FLOW ALOFT. LOOKING AHEAD TO THE MEMORIAL DAY
WEEKEND...THE MODELS INDICATE AT LEAST SLIGHT CHANCE POPS AS THE
PATTERN CONTINUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 82 71 85 72 83 / 80 20 30 50 60
AUSTIN BERGSTROM INTL AIRPORT 82 71 84 73 84 / 80 20 30 40 60
NEW BRAUNFELS MUNI AIRPORT 82 70 84 72 83 / 80 20 30 30 60
BURNET MUNI AIRPORT 80 69 82 70 81 / 60 20 40 70 70
DEL RIO INTL AIRPORT 83 71 87 69 85 / 30 20 30 50 40
GEORGETOWN MUNI AIRPORT 80 70 83 71 82 / 70 20 40 60 70
HONDO MUNI AIRPORT 82 71 85 72 83 / 80 20 30 40 60
SAN MARCOS MUNI AIRPORT 81 71 85 72 83 / 80 20 30 30 60
LA GRANGE - FAYETTE REGIONAL 82 72 85 74 85 / 80 20 30 20 40
SAN ANTONIO INTL AIRPORT 82 71 84 72 83 / 80 20 30 40 60
STINSON MUNI AIRPORT 83 72 86 73 84 / 80 20 30 40 50
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 5 PM CDT THIS AFTERNOON FOR THE FOLLOWING
COUNTIES: DE WITT...FAYETTE...GONZALES...KARNES...LAVACA...LEE...
WILSON.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...24
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
1044 AM CDT FRI MAY 15 2015
.DISCUSSION...BASED ON CURRENT RADAR TRENDS WHICH SHOW AN
INCREASING PUSH TO THE ESE...AND HRRR/NSSL OUTPUT...HAVE INCREASED
POPS ACROSS THE ERN HALF OF THE CWA FOR THIS AFTERNOON. ALSO
INCREASED QPF UP TO HALF AN INCH FOR AVGS...BUT LOCAL AMOUNTS
COULD BE MUCH HIGHER. THE HRRR PROGS AROUND 3-5 INCHES ACROSS THE
COASTAL BEND THIS AFTERNOON. UPDATES WILL BE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 750 AM CDT FRI MAY 15 2015/
DISCUSSION...UPDATED TO GO WITH A FFA ACROSS ALL OF THE CWA
TODAY. EVEN IF RAINFALL DECREASES AS IT MOVES FARTHER EAST THIS
AFTERNOON...IT WILL NOT TAKE MUCH TO CAUSE ADDITIONAL FLOODING
PROBLEMS ACROSS AREAS ALREADY SATURATED AND FLOODED. AN MCS HAS
DVLPD ACROSS THE NW CWA AND SEVERAL MODELS SHOW THIS PROGRESSING
EAST THROUGH THE DAY. ALSO CAN NOT RULE OUT SEVERE WX GIVEN THE
UPPER SHORT WAVE...INSTABILITY AND THE ABUNDANT MOISTURE.
PREV DISCUSSION... /ISSUED 619 AM CDT FRI MAY 15 2015/
DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...MVFR CIGS WERE MAINLY OVER THE BRUSH COUNTRY...NOT
AS PREVALENT OVER THE COASTAL PLAINS. WILL KEEP A MENTION OF
LOWER CIGS IN TEMPO GROUP FOR COASTAL SITES THIS MORNING ALONG
WITH PATCHY FOG FOR ALI/VCT.
SATELLITE IMAGERY SHOWS THE STRONG UPPER TROUGH MOVING THROUGH
COAHUILA INTO THE RIO GRANDE PLAINS EARLY THIS MORNING. THE
CONVECTION HAS NOT FORMED AS MUCH OVER NORTHEAST MEXICO WHILE
ACTIVITY NORTHWEST OF COTULLA REMAINS STRONG. THIS ACTIVITY WILL
MOVE EAST INTO THE WESTERN BRUSH COUNTRY DURING THE EARLY MORNING
HOURS. EXPECT SCATTERED STORMS TO FORM OVER COASTAL BEND LATER
THIS MORNING INTO THE AFTERNOON HOURS.
CONVECTION SHOULD DIMINISH OVER THE BRUSH COUNTRY BY EARLY
AFTERNOON WHILE DIMINISHING TREND WILL NOT OCCUR UNTIL LATE
AFTERNOON FOR COAST. MVFR CIGS WILL MOVE BACK INTO THE REGION
EARLY FRIDAY EVENING. EXPECT IFR CIGS WILL OCCUR FOR COASTAL
SITES BY MIDNIGHT AND CONTINUE THROUGH THE NIGHT.
PREV DISCUSSION... /ISSUED 419 AM CDT FRI MAY 15 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...CONVECTION HAS PERSISTED
BETWEEN COTULLA AND UVALDE EARLY THIS MORNING BUT ACTIVITY LOOKS
LIKE IT IS STARTING TO MOVE. WATER VAPOR IMAGERY SHOWS A STRONG
SHORT WAVE TROUGH MOVING INTO THE TEXAS BIG BEND/COAHUILA AHEAD
OF THE DEEP CLOSED LOW MOVING INTO THE GREAT BASIN. EXPECT THIS
SHORT WAVE TROUGH WILL TRACK NORTHEAST ACROSS THE AREA TODAY AND
BE NORTHEAST OF THE AREA BY LATE AFTERNOON. THE BLENDED TOTAL
PRECIPITABLE WATER IMAGE EARLIER THIS MORNING SHOWED THE DEEPER
MOISTURE AXIS ALONG THE RIO GRANDE WITH VALUES BETWEEN 1.7-1.9
INCHES. MOST OF THE MODELS DEVELOPED EXPANSIVE AREA OF CONVECTION
AHEAD OF THIS SHORT WAVE TROUGH OVER NORTHEAST MEXICO EARLY THIS
MORNING...WHICH MOST OF THE HI-RES MODELS MOVED THROUGH SOUTH
TEXAS TODAY. BUT ACTIVITY OVER NORTHEAST MEXICO ONLY ISOLATED
BUT SHOULD SEE CONVECTION INCREASE AS UPPER LEVEL SUPPORT FROM
THE WEST ARRIVES OVER BETTER MOISTURE ALONG THE RIO GRANDE.
WILL CONTINUE WITH LIKELY POPS OVER THE BRUSH COUNTRY WITH A
MENTION OF LOCALLY HEAVY RAIN POSSIBLY THIS MORNING. CONTEMPLATED
ISSUING A FLASH FLOOD WATCH FOR THE BRUSH COUNTRY AS ANY AMOUNT
OF HEAVY RAIN OVER SATURATED GROUNDS WILL BECOME RUNOFF. BUT
SPEED OF SHORT WAVE TROUGH MOVING THROUGH THE AREA AND SOMEWHAT
LOWER CONFIDENCE DUE TO MESO-SCALE MODELS HANDLING OF CURRENT
TREND...WILL HOLD OFF ON WATCH. KEPT SLIGHT CHANCE POPS IN FOR
THIS EVENING...BUT EXPECT LIMITED RAIN CHANCES OVERNIGHT INTO
SATURDAY MORNING. AFTER SHORT WAVE TROUGH GOES BY...MID LEVEL
WARMING OCCURS STRENGTHENING THE CAP. THE UPPER LOW OVER THE
GREAT BASIN MOVES NORTHEAST ACROSS THE FOUR CORNERS REGION ON
SATURDAY. A WEAK SHORT WAVE TROUGH WILL MOVE OUT OF NORTHERN
MEXICO WITH THE POSSIBILITY OF AN UPPER LEVEL JET STREAK NOSING
INTO THE BRUSH COUNTRY IN THE AFTERNOON. AIR MASS WILL BE CAPPED
FOR MOST OF THE DAY. BUT WITH STRONG HEATING...COULD SEE THE CAP
BROKEN WITH ISOLATED TO SCATTERED STRONG CONVECTION DEVELOP BY
MID-LATE AFTERNOON OVER THE BRUSH COUNTRY INTO THE INLAND
PORTIONS OF THE COASTAL BEND.
MARINE...LOW PRESSURE WILL BE DEEPENING OVER THE SOUTHERN AND
CENTRAL HIGH PLAINS TONIGHT INTO SATURDAY AS THE UPPER LOW OVER
GREAT BASIN APPROACHES. ONSHORE FLOW WILL INCREASE TO MODERATE
OVER THE COASTAL WATERS TONIGHT INTO SATURDAY. SCEC CONDITIONS
WILL EXIST FOR THIS PERIOD...MAY EVEN APPROACH SCA CONDITIONS
AT TIMES.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...ANY CONVECTION FROM
THE DAYTIME HOURS SATURDAY SHOULD QUICKLY DIMINISH BY SATURDAY
EVENING AS S/W DISTURBANCE SHIFTS TO THE NE OF THE CWA AND DRIER AIR
AT H85 TRIES TO BUILD INTO THE REGION FROM THE SOUTHEAST. ON
SUNDAY...ANOTHER MID LEVEL S/W TROUGH CAUGHT IN THE SW FLOW WILL
SKIRT NE ACROSS THE REGION WHILE AT THE SAME TIME UPPER LEVEL
DIVERGENCE IS PROG TO INCREASE...ESPECIALLY ACROSS NORTHERN AND
WESTERN COUNTIES. CLOSER THE SURFACE...A WEAK SURFACE BOUNDARY IS
PROG TO SHIFT INTO THE EDWARDS PLATEAU WITH CONVECTION LIKELY
IGNITING ALONG THE BOUNDARY TO OUR NORTH...WITH ADDITIONAL
CONVECTION DEVELOPING ACROSS THE CWA AS DIURNAL INSTABILITY
INCREASES AND DYNAMICS ALOFT IMPROVE. HAVE CHANCE POPS FOR
CONVECTION SUNDAY /ESPECIALLY IN THE AFTERNOON/ WITH CONVECTION
POSSIBLY PERSISTING INTO THE EVENING HOURS AS LLVL MOISTURE INFLUX
INCREASES. SFC BOUNDARY WASHES OUT/SHIFTS FARTHER N ON MONDAY WITH
UPPER LEVEL DIVERGENCE SHIFTING N AS WELL. THUS...PRECIP CHANCES ON
MONDAY SHOULD REMAIN LOW...THOUGH NOT NIL. MID/UPPER LEVEL RIDGING
BUILDS INTO THE REGION FOR MID WEEK WITH LLVL DRIER AIR /JUST ABOVE
THE SFC/ BUILDING IN FROM THE WESTERN GULF...AND THUS PRECIP CHANCES
WILL BE VERY LOW TO NON MENTIONABLE. DESPITE HIGH SOIL MOISTURE
LEVELS...MAX TEMPS HAVE BEEN REACHING GUIDANCE LEVELS PAST COUPLE OF
DAYS...AND WITH SOME RIDGING EXPECTED BY MID WEEK I AM EXPECTING MAX
TEMPS TO WARM FURTHER /90S NEARLY AREAWIDE/ IN THE EXTENDED PERIOD.
MIN TEMPS WILL CONTINUE TO BE ABOVE NORMAL FOR THIS TIME OF YEAR
GIVEN NOCTURNAL CLOUD COVER AND HUMID CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 85 76 87 77 88 / 80 20 20 10 30
VICTORIA 84 73 87 75 88 / 80 20 20 10 40
LAREDO 88 75 94 75 94 / 70 20 20 10 40
ALICE 86 75 90 75 91 / 80 20 30 10 40
ROCKPORT 83 77 86 78 87 / 80 10 20 10 30
COTULLA 85 73 90 73 90 / 80 20 30 10 40
KINGSVILLE 86 76 89 77 89 / 80 20 20 10 40
NAVY CORPUS 83 78 85 78 86 / 80 20 20 10 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...JIM
WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...NUECES...
REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
GM...NONE.
&&
$$
TE/81...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1206 AM CDT FRI MAY 15 2015
.UPDATE...
A LOOSELY ORGANIZED CLUSTER OF T-STORMS CONTINUES TO MOVE SLOWLY
THROUGH THE ROLLING PLAINS AND FAR SE TX PANHANDLE. SEVERE
WEATHER IS NOT EXPECTED OVERNIGHT...BUT HEAVY RAINFALL MAY CAUSE
SOME LOCALIZED FLOODING.
&&
.AVIATION...
TSRA WILL CONTINUE IN THE VICINITY OF KCDS THROUGH 07 UTC OR SO.
OTHERWISE...PATCHY STRATUS MAY BRING SOME LOW CEILINGS AT KPVW
AND KLBB THROUGH ABOUT SUNRISE BUT CONFIDENCE IN THIS IS LOW.
SURFACE WINDS WILL RETURN TO THE S-SW AND BECOME BREEZY DURING THE
DAY FRIDAY. SCATTERED TSRA WILL DEVELOP LATE IN THE DAY WITH A
GOOD CHANCE TO IMPACT SOME OR ALL OF THE TERMINALS FRIDAY
EVENING.
&&
.PREV DISCUSSION... /ISSUED 657 PM CDT THU MAY 14 2015/
UPDATE...
THE SEVERE THUNDERSTORM WATCH HAS BEEN EXPANDED TO COVER THE
ENTIRE FORECAST AREA THROUGH 11 PM. THE LATEST HRRR GRADUALLY
MORPHS THE CLUSTER OF TSTMS ACROSS THE WRN SPLNS INTO A SQUALL
LINE WHICH THEN MOVES EAST TONIGHT. WE HAVE ALSO INCREASE THE POPS
FOR MOST AREAS.
AVIATION...
-TSRA IS EXPECTED AT KLBB AND PVW THIS EVENING...THEN SEVERAL
HOURS LATER AT KCDS. SOME SEVERE WIND WINDS AND LARGE HAIL ARE
POSSIBLE. VFR CONDITIONS WILL RETURN LATE TONIGHT...ALTHOUGH
THERE IS A LOW POTENTIAL FOR LOW CEILINGS...ESPECIALLY AT KCDS. SW
BREEZES WILL INCREASE FRIDAY MORNING.
PREV DISCUSSION... /ISSUED 214 PM CDT THU MAY 14 2015/
SHORT TERM...
FORECAST THINKING CONTINUES ON TRACK WITH THAT PROVIDED IN THE NOON
UPDATE. CAPE VALUES HAVE INCREASED A FAIR BIT IN THE LATEST
MESOANALYSES PEAKING AT VALUES IN EXCESS OF 3KJ/KG PARTICULARLY
ACROSS OUR SOUTHERN COUNTIES. BULK SHEAR CONTINUES TO BE RUNNING
AROUND 35 KTS THOUGH ONE OF THE MORE REMARKABLE FIELDS IN THIS
MORNING/S RUNS IS THE HELICITY...MOST NOTABLE THE 0-1KM FIELDS WHICH
RAMP UP RAPIDLY THIS EVENING. THE ONE NEGATIVE...AND HISTORICALLY
THIS CAN BE A DEAL-BREAKER...IS THE PRESENCE OF A PERSISTENT CIRRUS
SHIELD. AS SUCH THE SEVERE THREAT IS CONDITIONAL ON INITIATION OF
DEEP CONVECTION. HOWEVER...IF THINGS DO BECOME ESTABLISHED...ALL
FORMS OF CONVECTIVE SEVERE WILL BE LIKELY. DATA SUGGESTS THAT THE
WINDS WILL RAPIDLY BACK AROUND 00Z WITH ATTENDANT LOW LEVEL MOISTURE
SURGE AND ENHANCE THE TORNADO THREAT. ASSUMING DEEP CONVECTION
OCCURS...WOULD LOOK FOR INITIAL ACTIVITY TO BE SOMEWHAT DISCRETE AND
EVOLVE TOWARD SOME SORT OF QLCS LATER THIS EVENING. AFTER THE
ACTIVITY WANES THIS EVENING...COULD SEE A BIT OF FOG TOWARD
MORNING ESPECIALLY ACROSS THE ROLLING PLAINS. WITH THAT OUT OF THE
WAY...WE SHOULD GET A RESPITE IN CONVECTION UNTIL LATE FRIDAY
AFTERNOON OR EVENING WITH ANOTHER SYSTEM MOVING ACROSS AS
DISCUSSED IN THE LONG TERM.
LONG TERM...
MODELS ARE CHANGING COURSE A LITTLE BIT WITH REGARDS TO FRIDAY
CONVECTION. THE UPPER LEVEL JET STREAK WILL COME OUT OF THE
SOUTHWESTERN US FARTHER SOUTH CLOSER TO WEST TEXAS. THIS WILL
LEAVE THE REGION IN DIVERGENCE FLOW ALOFT. OVERNIGHT CONVECTION
LOOKS MORE LIKELY FROM FRIDAY NIGHT THROUGH MUCH OF SATURDAY
MORNING. A PACIFIC COLD FRONT WILL EVENTUALLY OVERTAKE A
RETREATING DRYLINE FRIDAY NIGHT DEVELOPING CONVECTION INITIALLY IN
EASTERN NEW MEXICO. A LOW LEVEL JET RAMPING UP WILL SUSTAIN
CONVECTION IN MORE OR LESS OF A LINEAR FORM. THIS WILL BE COUPLED
WITH STRONG HEIGHT FALLS OVERNIGHT. STEEPER LAPSE RATES ENTERING
THE REGION BECAUSE OF COOLING ALOFT WILL ALLOW THE POSSIBILITY OF
SEVERE STORMS. THE PACIFIC COLD FRONT WILL THEN STALL OUT OVER THE
ROLLING PLAINS WITH STRONGER LOW LEVEL CONVERGENCE ON SATURDAY
AFTERNOON. THE UPPER LEVEL JET POSITION WILL FAVOR THE CENTRAL
PLAINS RATHER THAN THE SOUTHERN HIGH PLAINS. ALTHOUGH THE SURFACE
CONVERGENCE WILL FAVOR SOME INITIATION SATURDAY AFTERNOON OR
EVENING OVER THE ROLLING PLAINS.
SUNDAY WILL SEE A BREAK FROM THE CONVECTION CHANCES AS THE
LONGWAVE TROUGH EJECTS OUT INTO THE PLAINS AND MIDWEST. A CANADIAN
COLD FRONT ON MONDAY WILL ALLOW LOW LEVEL MOISTURE TO BE DRAWN
BACK INTO THE REGION. OUR UNSETTLED WEATHER PATTERN WILL CONTINUE
NEXT WEEK WITH WESTERN CONUS TROUGHING RAPIDLY DEVELOPING AGAIN
NEXT WEEK. AT THE MOMENT...MONDAY-TUESDAY IS THE AGREED UPON
TIME FRAME FOR BEST CONVECTION IN BOTH THE GFS AND ECMWF.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 55 77 53 74 / 10 10 50 0
TULIA 58 79 58 77 / 30 10 60 10
PLAINVIEW 59 79 59 77 / 30 10 60 10
LEVELLAND 59 80 59 78 / 10 10 60 0
LUBBOCK 60 81 61 80 / 30 10 60 10
DENVER CITY 59 81 58 78 / 10 10 60 0
BROWNFIELD 61 82 60 80 / 10 10 60 10
CHILDRESS 64 83 64 83 / 70 10 60 50
SPUR 63 82 63 83 / 70 10 60 20
ASPERMONT 66 83 66 85 / 70 20 60 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1142 PM CDT THU MAY 14 2015
.DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
MAINLY VFR CONDITIONS WILL BECOME MVFR AT MOST SITES BY 09Z. IF
THE LATEST HRRR IS CORRECT...SHOWER AND THUNDERSTORMS MAY BEGIN
AFFECTING KCLL BEFORE 12Z. HOWEVER...FELT THAT A CONSENSUS OF THE
OTHER MODELS IS A BETTER SOLUTION. FOR MOST SITES EXPECT SHOWERS
AFTER 15Z AND THUNDERSTORMS AFTER 18Z. STREAMER SHOWERS ARE
POSSIBLE AT THE COAST BY 10Z.
40
&&
.PREV DISCUSSION... /ISSUED 900 PM CDT THU MAY 14 2015/
UPDATE...
SEE EVENING UPDATE.
DISCUSSION...
00Z SOUNDINGS SHOW PW VALUES NEAR 1.50 INCHES WITH SOME SLIGHTLY
DRIER AIR IN THE 850-700 LAYER. SFC ANALYSIS SHOWS TWO WEAK
OUTFLOW BOUNDARIES...ONE JUST SOUTH OF LUFKIN AND ANOTHER BETWEEN
HONDO AND COTULLA. NEITHER FEATURE LOOK TO BE MUCH OF A FACTOR
FOR WX OVER SE TX. BEST 850 MB MSTR IS OVER N TX/S OK BUT
DISCERNIBLE TROUGHS WERE NOTED OVER THE STATE. 700 MB MSTR WAS
LOCATED OVER W LA WITH SUBTLE WARMING AT THE 700 MB LEVEL. 300 MB
ANALYSIS SHOWS UPPER LEVEL WINDS REMAIN DIVERGENT OVER THE
EASTERN 2/3RDS OF THE STATE AND THIS IS NOT EXPECTED TO CHANGE
OVER THE NEXT 24 HOURS.
SHRA/TSRA ACTIVITY HAS WANED WITH THE LOSS OF HEATING BUT STILL
WATCHING AN AREA OF CONVECTION OVER SOUTH TEXAS MOVING TOWARD
JACKSON COUNTY. FEEL THIS ACTIVITY WILL WEAKEN AS IT MOVES EAST
AND PROBABLY DISSIPATE. SHORT TERM MODELS SHOW SOME STREAMER
SHRA DEVELOPING AFTER 06Z SO WILL LEAVE 20 POPS FOR TONIGHT.
SHORT TERM GUIDANCE IS BULLISH WITH RAIN CHANCES ON FRIDAY. THE
RAP/GFS/NAM ALL SHOW A STRONG VORT LOBE MOVING INTO THE AREA IN
THE EARLY AFTN. UPPER LEVEL WINDS REMAIN DIVERGENT WITH A SPEED
MAX APPROACHING IN THE AFTN. FCST SOUNDINGS SHOW PW VALUES PEAKING
BETWEEN 1.7-1.9 INCHES BY 21Z AND CONVECTIVE TEMPS BETWEEN 80 AND
83 DEGREES. THE ECMWF AND CANADIAN ARE CONSIDERABLY DRIER WITH
LITTLE TO NO RAIN FOR THE AREA. WILL AWAIT THE 00Z MODELS BEFORE
POSSIBLY RAISING POPS FOR FRIDAY.
LASTLY...SOME HEFTY RAINFALL TOTALS YET AGAIN TODAY WITH KUTS
TOPPING THE CHARTS WITH 1.94 INCHES. SEE THE CLIMATE SECTION BELOW
FOR OTHER CLIMATE INFORMATION. SOME 3-4 INCHES TOTALS IN HOUSTON
COUNTY...AND 2-3 INCH TOTALS IN PARTS OF WALKER...MONTGOMERY AND
AUSTIN COUNTIES. 43
CLIMATE...
AS MENTIONED ABOVE HUNTSVILLE (KUTS) RECEIVED 1.94 INCHES OF RAIN
TODAY. THIS BRINGS THE MONTHLY TOTAL TO 7.53 INCHES. THE MAY
MONTHLY AVERAGE IS 4.94 INCHES. OVER THE LAST 30 DAYS (APR 15
THROUGH MAY 15)...HUNTSVILLE HAS RECEIVED 13.94 INCHES OF RAIN.
SUGAR LAND (KSGR) RECEIVED 1.24 INCHES OF RAIN TODAY WITH A
MONTHLY TOTAL OF 5.11 INCHES AND A 30 DAY TOTAL OF 12.83 INCHES.
HOUSTON HOBBY ONLY RECEIVED A TRACE OF RAIN TODAY BUT HAS A 30 DAY
TOTAL OF 11.37 INCHES. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 71 83 71 86 72 / 20 40 20 30 30
HOUSTON (IAH) 72 84 72 86 74 / 20 40 20 30 20
GALVESTON (GLS) 76 80 76 82 76 / 20 40 20 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
901 PM EDT SAT MAY 16 2015
.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL MAINTAIN A MOIST SOUTHERLY FLOW OF AIR
ACROSS THE REGION THROUGH MONDAY. A COLD FRONT WILL SLOWLY
APPROACH FROM THE WEST LATE MONDAY...MOVING THROUGH THE REGION
TUESDAY. COOLER...DRIER AIR WILL FILTER INTO THE REGION BY THE
MID PART OF NEXT WEEK BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 835 PM EDT SATURDAY...
MAIN CORRIDOR OF CONVECTION REMAINS ACROSS THE FAR WESTERN THIRD
THIS EVENING IN AN AXIS OF HIGHER CAPE UNDER A WEAK CONVERGENCE
AREA ALONG THE TAIL OF ANOTHER PASSING WEAK MID LEVEL WAVE.
EVENING RNK SOUNDING SHOWING THINGS QUITE SATURATED WITH MOIST
PWATS AND WEAK VEERING OVERTOP RATHER STRONG INSTABILITY. THUS
APPEARS AT LEAST SHALLOW CONVECTION MAY CONTINUE TO LINGER A BIT
LONGER WEST AS STILL SEEING NEW DEVELOPMENT OFF OUTFLOW BANDS.
THUS KEEPING LIKELY/HIGH CHANCE POPS GOING ESPCLY VA HIGHLANDS/SE
WEST VA UNTIL JUST BEFORE MIDNIGHT. LATEST HRRR ALSO SHOWS SOME
COVERAGE OUT TO THE BLUE RIDGE IN VIRGINIA WHERE INSTABILITY YET
TO BE WORKED OVER MUCH. THEREFORE LEAVING IN SOME CHANCE POPS
FARTHER EAST INTO THE EARLY MORNING HOURS BEFORE ENOUGH
COOLING...AND LESS UPPER SUPPORT FINALLY CAUSES SHRA TO FADE. OTRW
DEGREE OF DEBRIS CLOUDS MAKING THINGS A BIT TRICKY WITH FOG
COVERAGE OVERNIGHT AS SHOULD STILL SEE RATHER WIDESPREAD
FOG/STRATUS WEST WHERE HEAVY RAIN HAS OCCURRED. ELSEWHERE APPEARS
PATCHY COVERAGE OUTSIDE OF AREAS THAT HAVE SEEN THE HEAVY
DOWNPOURS...AND MOSTLY IN THE LOW SPOTS/VALLEYS PROVIDED A BIT OF
CLEARING LATER. SOUPY ENVIRONMENT WILL ONLY ALLOW FOR GRADUAL TEMP
FALLS OVERNIGHT WITH MOST SPOTS STAYING IN THE 60S EXCEPT FOR
PERHAPS A FEW 50S NW VALLEYS.
PREVIOUS DISCUSSION AS OF 303 PM EDT SATURDAY...
SUBTROPICAL RIDGE CONTINUES FROM THE SOUTHEAST STATES INTO THE MID-
ATLANTIC REGION THIS AFTERNOON INTO SUNDAY. A SOUTHERLY FLOW OF WARM
AND HUMID AIR COMBINING WITH INSTABILITY AND WEAK SHORTWAVES THIS
THIS AFTERNOON GENERATING SCATTERED SHOWERS AND THUNDERSTORMS. CAPES
THIS AFTERNOON VARY FROM 500 TO 1K J/KG...AND LIS AROUND MINUS 1 TO
MINUS 3...WITH INCREASED PWAT ABOUT AN INCH. INTERESTING TO NOTE
OFF THE 18Z SPC MESOANALYSIS OF A 800 DOWNDRAFT CAPE LOCATED TO
OUR NORTHEAST. AS INDICATED BY SWODY1...THE BETTER DYNAMIC AND
CHANCE FOR STRONGER TO SEVERE ARE LOCATED TO OUR NORTH AND WEST.
ONE CONCERN FOR THIS AFTERNOON INTO TONIGHT WILL BE THE POTENTIAL
FOR LOCALLY HEAVY RAINS WITH WEAK STEERING CURRENTS LEADING TO
SLOW MOVING THUNDERSTORMS...ESPECIALLY ACROSS ACROSS THE
MOUNTAINS. EXPECT MOST OF THE CONVECTION TO DIMINISH THIS EVENING
WITH THE LOSS OF SOLAR HEATING. CAN NOT COMPLETELY DRIER IT
OUT...BECAUSE THERE IS ANOTHER UPPER DISTURBANCE ROTATING ACROSS
THE REGION OVERNIGHT INTO SUNDAY MORNING. WITH LOW LEVEL MOISTURE
AND LIGHT WINDS ANTICIPATE THAT AREAS OF FOG WILL FORM OVERNIGHT
ESPECIALLY IN LOCATION THAT RECEIVE RAINFALL ON SATURDAY. LOW
TEMPERATURE OVERNIGHT WILL BE MILD WITH READINGS FROM THE UPPER
50S IN THE MOUNTAINS TO THE MID 60S IN THE PIEDMONT.
UPPER RIDGE WILL HOLD FAST THROUGH SUNDAY BUT GRADUALLY START TO
FLATTEN OUT AND SHIFT EAST AS SURFACE HIGH PRESSURE CENTERED OFF THE
MID ATLANTIC COAST SURFACE SINKS FURTHER TO THE SOUTH. THE DAY TWO
CONVECTION KEEPS US IN GENERAL THUNDERSTORMS SUNDAY WITH BEST
DYNAMICS REMAINING TO OUR WEST. THE OROGRAPHIC FORCING WILL SERVE AS
THE PRIMARY MECHANISM FOR DIURNAL CONVECTION...ALONG WITH OUTFLOW
BOUNDARY INTERACTIONS AND POSSIBLY SOME WEAK UPPER SHORT WAVE
ENERGY. HIGH TEMPERATURES ON SUNDAY WILL RANGE FROM THE LOWER 70S IN
THE MOUNTAINS TO THE UPPER 80S IN THE PIEDMONT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 300 PM EDT SATURDAY...
MODELS CONTINUE TO BE IN GOOD AGREEMENT DURING SHORT TERM PERIOD IN
MAINTAINING A SOUTHEASTERN UPPER RIDGE AMPLIFYING INTO THE
BLACKSBURG FORECAST AREA THROUGH MONDAY NIGHT BEFORE BEING GRADUALLY
FLATTENED BY A SHORT WAVE TROF EXPECTED TO MOVE EAST THROUGH THE
GREAT LAKES ON TUESDAY.
WITH THE UPPER RIDGE HOLDING UNTIL TUESDAY...SLOWLY INCREASING HEAT
AND HUMIDITY ON LIGHT SOUTHWESTERLY FLOW ALONG THE PERIPHERY OF THE
UPPER RIDGE WILL CONTINUE TO SUPPORT DEVELOPMENT OF MAINLY DIURNALLY-
DRIVEN SHOWERS AND THUNDERSTORMS...MOST NOTABLY IN THE MOUNTAINS
WHERE THETA-E VALUES WILL BE THE HIGHEST...AND WHERE LOCALIZED
FORCED ASCENT AND DIFFERENTIAL HEATING DUE TO OROGRAPHIC INFLUENCES
WILL BE MAXIMIZED TO PUNCH THROUGH WEAK MID-LEVEL CAPPING INVERSION.
FORECAST SOUNDINGS CONTINUE TO MAINTAIN RELATIVELY WARM TEMPERATURES
IN THE MID LEVELS OF THE ATMOSPHERE ALONG WITH WEAK SHEAR INTO
TUESDAY...SUCH THAT SEVERE WEATHER THREAT EVEN UP THROUGH FRONTAL
PASSAGE ON TUESDAY APPEARS TO BE EXTREMELY LIMITED. CORFIDI VECTORS
YIELD A SLOW...BUT SUFFICIENTLY PROGRESSIVE MOTION SUCH THAT UNLESS
TRAINING ALONG AN OUTFLOW BOUNDARY AND/OR ANCHORING ON A OROGRAPHIC
POINT OCCURS...FLASH FLOODING THREAT SHOULD ALSO REMAIN MINIMAL
DESPITE PRECIPITABLE WATER VALUES GRADUALLY CLIMBING UP TO AND
MAXING OUT IN THE 1.6 - 1.8 INCH RANGE SUNDAY INTO MONDAY.
PASSAGE OF SHORT WAVE TROF AND ATTENDANT COOL FRONT LATER TUESDAY
SHOULD SHOULD BRING AN END TO THREAT FOR SCATTERED SHOWERS/STORMS
BY/DURING TUESDAY EVENING AS COOL ADVECTION IN WEST...AND
DOWNSLOPING EAST OF THE BLUE RIDGE TAKES OVER...SETTING THE STAGE
FOR DRIER AND SLIGHTLY COOLER WEATHER LATER TUESDAY NIGHT INTO THE
FIRST PART OF THE LONGER TERM PERIOD.
TEMPERATURES THROUGH THE PERIOD WILL CONTINUE TO BE LARGELY GOVERNED
BY EXTENT OF CLOUD COVER AND INFLUENCE OF CONVECTIVE OUTFLOW
BOUNDARIES...BUT NOT EXPECTED TO BE THAT FAR OFF CLIMATOLOGICAL
NORMALS AREA-WIDE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 PM EDT SATURDAY...
SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTHWEST SHOULD MAINTAIN
DRY AND SLIGHTLY COOLER WEATHER FOR THE BLACKSBURG FORECAST AREA
WEDNESDAY INTO AT LEAST THURSDAY MORNING.
APPROACH OF YET ANOTHER SERIES OF NORTHERN STREAM IMPULSES EXPECTED
TO SUFFICIENTLY BUCKLE/BACK UPPER FLOW AGAIN IN THURSDAY/FRIDAY
TIMEFRAME TO SUPPORT THE DEVELOPMENT OF WIDELY SCATTERED SHOWERS OR
ISOLATED THUNDERSHOWERS...MAINLY ACROSS THE SOUTHWESTERN VA INTO THE
MOUNTAINS OF NW NC WHERE RETURN FLOW AND THETA-E WILL BE A BIT
HIGHER.
OTHERWISE...ANOTHER RETURN TO DRIER WEATHER LOOKS TO BE IN THE
OFFING BY NEXT SATURDAY AS PASSAGE OF NORTHERN STREAM WAVES
SUFFICIENTLY DEEPENS/REESTABLISHES UPPER TROF OVER NEW
ENGLAND...SUPPORTING SURFACE HIGH PRESSURE THAT WILL SLIDE SOUTHEAST
INTO NEW ENGLAND AND WEDGE SOUTHWESTWARD INTO THE MID ATLANTIC
STATES.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
AS OF 640 PM EDT SATURDAY...
CLUSTERS OF DEEP CONVECTION REMAIN CONFINED TO THE FAR
WEST...MAINLY ALONG THE KMKJ-KBLF-KLWB CORRIDOR THIS EVENING. THIS
MAINLY OUTFLOW DRIVEN AND AIDED BY OROGRAPHICS/RESIDUAL
INSTABILITY SO EXPECTING COVERAGE TO LINGER AN HOUR OR TWO PAST
SUNSET. THIS MAY RESULT IN PERIODS OF MVFR/IFR IN TSRA/SHRA AT
BOTH KBLF/KLWB EARLY THIS EVENING BEFORE COVERAGE FADES WITH
COOLING AFTER DARK. ELSEWHERE MAINLY LOOKING AT VFR WITH ONLY A
POP UP SHRA POSSIBLE ALONG THE KBCB-KROA-KLYH ROUTE THIS EVENING.
ONCE CONVECTION FADES SHOULD SEE A FEW HOURS OF VFR AT ALL
LOCATIONS BEFORE FOG/LOW CLOUDS START TO DEVELOP ESPCLY WHERE
HEAVIER RAINFALL HAS OCCURRED. THIS WOULD AGAIN IMPACT KLWB/KBLF
WHERE MAY SEE VSBYS QUICKLY LOWER TO MVFR/IFR AROUND MIDNIGHT AND
THEN LIFR ESPCLY AT KLWB OVERNIGHT. A BIT LOWER CONFIDENCE
ELSEWHERE GIVEN ONLY SPOTTY EARLIER SHRA ALONG THE BLUE RIDGE
WHERE KROA COULD BRIEFLY LOWER TO MVFR IN FOG AFTER EARLIER
RAINFALL. EXPECT TO SEE SOME RADIATIVE FOG AT MOST OTHER LOCATIONS
BUT DELAYED THE ONSET GIVEN CURRENT DRIER CONDITIONS AND POTENTIAL
FOR ONLY BRIEF MVFR/IFR. THUS WENT THE TEMPO ROUTE FOR LOWER
CONDITIONS LATER TONIGHT OUT EAST INCLUDING POSSIBLE LIFR AT KBCB
AROUND DAYBREAK.
SUNDAY SHOULD BRING AN ALMOST IDENTICAL PATTERN TO TODAY WITH
SCATTERED...MAINLY AFTERNOON/EVENING THUNDERSTORMS...MOST NUMEROUS
WEST OF THE BLUE RIDGE. SINCE COVERAGE LOOKS A BIT MORE WIDESPREAD
SUB-VFR CONDITIONS LOOK TO OCCUR EARLIER AND LIKELY MORE
WIDESPREAD AT LEAST OUT TO THE BLUE RIDGE. KDAN MAY AGAIN STAY
SOUTH OF ANY CONVECTION SO LEFT OUT MENTION THERE SUNDAY
AFTERNOON. FOR THE REMAINDER...APPEARS ENOUGH SHRA/TSRA TO
INCLUDE WITH AN AFTERNOON PREVAILING MVFR GROUP AT MOST OTHER
SITES...WITH THE EXCEPTION BEING KLYH WHERE GOING WITH MORE
VICINITY COVERAGE SINCE THEY WILL BE ON THE EASTERN EDGE OF THE
MORE ORGANIZED TSRA LATER SUNDAY.
MEDIUM TO HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS
DURING THE TAF PERIOD.
EXTENDED AVIATION DISCUSSION...
LATE NIGHT/EARLY MORNING FOG AND ASSOCIATED IFR-LIFR VSBYS/CIGS
BECOME INCREASINGLY LIKELY SUNDAY NIGHT INTO MONDAY GIVEN THE
SOUPY ATMOSPHERE IN PLACE. LATE MONDAY INTO TUESDAY...A COLD
FRONT MOVES THROUGH. THUNDERSTORMS SHOULD BE MOST NUMEROUS IN
COVERAGE AND STRONGEST IN INTENSITY DURING THIS TIME FRAME FOR ALL
AREAS...ENDING FROM THE WEST DURING TUESDAY. LONGER PERIODS OF
MVFR CIGS/VSBYS APPEAR LIKELY MONDAY-TUESDAY. BEHIND THE COLD
FRONT...DRIER/COOLER CONDITIONS ARE EXPECTED WED-THU WITH MOSTLY
VFR CONDITIONS AS HIGH PRESSURE SLIDES IN FROM THE NW.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/RAB
NEAR TERM...JH/KK
SHORT TERM...WERT
LONG TERM...WERT
AVIATION...JH/KK/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
127 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1207 PM EDT FRIDAY...
MADE SOME MINOR ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES
ALONG AND EAST OF THE SOUTHERN BLUE RIDGE MOUNTAINS WITH MVFR
CLOUDS HOLDING LONGER. IT WILL TAKE A FEW HOURS LONGER BEFORE
LOW CLOUDS LIFT THIS AFTERNOON.
AS OF 946 AM EDT FRIDAY...
ADJUSTED TEMPERATURES AND DEWPOINTS WITH THE LATEST OBS AND MODEL
TRENDS. MODIFIED CLOUD COVER TOWARDS LATEST SATELLITE IMAGE AND
TRENDED LATE MORNING INTO THIS AFTERNOON TOWARDS A BLEND OF THE
CANADIAN AND HRRR...WHICH CAPTURE THE SUNSHINE ACROSS SOUTHEAST
WEST VIRGINIA AND NEW RIVER VALLEY WITH RICHER CLOUDS ALONG THE
SOUTHERN BLUE RIDGE. HEATING WILL CREATE INSTABILITY COMBINED WITH
CAPES OF AROUND 500 TO 1000 J/KG TO GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS. DAY ONE CONVECTIVE OUTLOOK PLACES THE SEVERE
THREAT TO OUR WEST. ALLOWED FOR LIGHT SHOWERS ALONG THE SOUTHERN
BLUE RIDGE THEN SHAPED POPS FOR LATE THIS MORNING INTO THIS
AFTERNOON TOWARDS A HRRR/RNK WRFARW. HIGH TEMPERATURES THIS
AFTERNOON WILL RANGE FROM THE UPPER 60S IN THE MOUNTAINS TO AROUND
80 DEGREES IN THE PIEDMONT.
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 130 PM EDT FRIDAY...
SHORTWAVE OVER THE REGION WILL MOVE EAST THIS AFTERNOON INTO
TONIGHT AND WILL FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST.
SOUTHWEST FLOW ABOVE THE SURFACE WILL CONTINUE TO TRANSPORT
MOISTURE INTO THE REGION.
A PERSISTENT LAYER OF MVFR STRATOCUMULUS REMAINS ALONG AND EAST
OF THE SOUTHERN BLUE RIDGE MOUNTAIN EXTENDING INTO THE SOUTHERN
PIEDMONT. THE ONLY TAF SITE BEING AFFECT BY THIS MVFR CLOUDS IS KDAN.
HOWEVER...WITH MIXING THIS AFTERNOON THIS IS EXPECTED TO LIFT TO
VFR CONDITIONS DURING THE NEXT COUPLE OF HOURS.
MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS. THE THREAT OF
THUNDERSTORMS HAS BEEN LIMITED BY THE UPPER RIDGE AND COVERAGE OF
CLOUD COVER. PROBABILITY IS HIGH ENOUGH TO INCLUDE MENTION OF SHOWERS
OR VCSH IN WESTERN MOUNTAIN TAF SITES THIS AFTERNOON INTO
TONIGHT. KBLF IS THE TAF SITE WITH THE BEST CHANCE FOR A
THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING...BUT BECAUSE OF
LIMITED COVERAGE WILL LEAVE MENTION OUT. ANY CONVECTION WILL
DISSIPATE QUICKLY TONIGHT WITH LOSS OF SOLAR HEATING. IF A
THUNDERSTORMS OCCURS AND IT RAINS ENOUGH AT A TAF LOCATION...WE
MAY NEED TO INSERT SOME PATCHY FOG OVERNIGHT.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
MEDIUM TO HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS
DURING THE TAF PERIOD.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY. DRIER AND COOLER AIR EXPECTED BEHIND THE FRONT
FOR MIDWEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1208 PM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1207 PM EDT FRIDAY...
MADE SOME MINOR ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES
ALONG AND EAST OF THE SOUTHERN BLUE RIDGE MOUNTAINS WITH MVFR
CLOUDS HOLDING LONGER. IT WILL TAKE A FEW HOURS LONGER BEFORE
LOW CLOUDS LIFT THIS AFTERNOON.
AS OF 946 AM EDT FRIDAY...
ADJUSTED TEMPERATURES AND DEWPOINTS WITH THE LATEST OBS AND MODEL
TRENDS. MODIFIED CLOUD COVER TOWARDS LATEST SATELLITE IMAGE AND
TRENDED LATE MORNING INTO THIS AFTERNOON TOWARDS A BLEND OF THE
CANADIAN AND HRRR...WHICH CAPTURE THE SUNSHINE ACROSS SOUTHEAST
WEST VIRGINIA AND NEW RIVER VALLEY WITH RICHER CLOUDS ALONG THE
SOUTHERN BLUE RIDGE. HEATING WILL CREATE INSTABILITY COMBINED WITH
CAPES OF AROUND 500 TO 1000 J/KG TO GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS. DAY ONE CONVECTIVE OUTLOOK PLACES THE SEVERE
THREAT TO OUR WEST. ALLOWED FOR LIGHT SHOWERS ALONG THE SOUTHERN
BLUE RIDGE THEN SHAPED POPS FOR LATE THIS MORNING INTO THIS
AFTERNOON TOWARDS A HRRR/RNK WRFARW. HIGH TEMPERATURES THIS
AFTERNOON WILL RANGE FROM THE UPPER 60S IN THE MOUNTAINS TO AROUND
80 DEGREES IN THE PIEDMONT.
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
AS OF 745 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
946 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 946 AM EDT FRIDAY...
ADJUSTED TEMPERATURES AND DEWPOINTS WITH THE LATEST OBS AND MODEL
TRENDS. MODIFIED CLOUD COVER TOWARDS LATEST SATELLITE IMAGE AND
TRENDED LATE MORNING INTO THIS AFTERNOON TOWARDS A BLEND OF THE
CANADIAN AND HRRR...WHICH CAPTURE THE SUNSHINE ACROSS SOUTHEAST
WEST VIRGINIA AND NEW RIVER VALLEY WITH RICHER CLOUDS ALONG THE
SOUTHERN BLUE RIDGE. HEATING WILL CREATE INSTABILITY COMBINED WITH
CAPES OF AROUND 500 TO 1000 J/KG TO GENERATE SCATTERED SHOWERS
AND THUNDERSTORMS. DAY ONE CONVECTIVE OUTLOOK PLACES THE SEVERE
THREAT TO OUR WEST. ALLOWED FOR LIGHT SHOWERS ALONG THE SOUTHERN
BLUE RIDGE THEN SHAPED POPS FOR LATE THIS MORNING INTO THIS
AFTERNOON TOWARDS A HRRR/RNK WRFARW. HIGH TEMPERATURES THIS
AFTERNOON WILL RANGE FROM THE UPPER 60S IN THE MOUNTAINS TO AROUND
80 DEGREES IN THE PIEDMONT.
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 745 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
749 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 745 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
747 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 130 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER.
A LAYER OF MVFR STRATOCUMULUS HAS SPREAD UP THE BLUE RIDGE INTO
KBCB. HIGH CONFIDENCE THAT THE CEILING WILL LIFT TO VFR BY
15Z/11AM. MODELS HAVE BEEN CONSISTENT IN FORECAST OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN MOUNTAINS.
PROBABILITY STILL HIGH ENOUGH TO INCLUDE SHOWERS IN THE VICINITY
OF KLWB/KBLF AND KBCB THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
405 AM EDT FRI MAY 15 2015
.SYNOPSIS...
HIGH PRESSURE WAS OFFSHORE THE MID ATLANTIC COAST THIS MORNING.
LOW PRESSURE OVER MINNESOTA WILL MOVE EAST ACROSS THE GREAT LAKES
TODAY AND TONIGHT. ANOTHER LARGE LOW OVER THE PLAINS ON SATURDAY
WILL MOVE EAST...AND PUSH A STRONG COLD FRONT THROUGH OUR REGION
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 350 AM EDT FRIDAY...
LARGE SHIELD OF CIRRUS COVERING THE FORECAST AREA THIS MORNING.
HRRR AND CANADIAN MODEL HAVE MOST OF THE HIGH CLOUDS MOVING EAST
OF THE AREA THIS MORNING. EXPECTING ENOUGH SUNSHINE TO PUSH
TEMPERATURES BACK UP INTO THE 70S. HEATING WILL ALSO GENERATE SOME
INSTABILITY. CAPES AROUND 500 J/KG ARE FORECAST THIS AFTERNOON.
LOCAL WRF AND HRRR SHOW SHOWERS AND THUNDERSTORMS DEVELOPING
STARTING AROUND NOON...WITH SCATTERED COVERAGE EXPECTED THROUGH
SUNSET.
LOCAL PROFILER AND TOTAL BLENDED PRECIPITABLE WATER PRODUCTS
CONFIRMED MOISTURE WAS ALREADY INCREASING THIS MORNING. AFTER
00Z/8PM PWIN VALUES WILL BE AROUND 1.0 INCH. CLOUDS AND HIGHER DEW
POINTS WILL HOLD TEMPERATURES IN THE 50S AND 60S TONIGHT. LEANED
TOWARD WARMER GUIDANCE VALUES FOR OVERNIGHT LOWS.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
AS OF 315 AM EDT FRIDAY...
MODELS HAVE BEEN VERY CONSISTENT IN ADVERTISING A SUMMER LIKE PATTERN
OVER US THIS WEEKEND FOR THE PAST SEVERAL RUNS IN THE SHAPE OF A LARGE
UPPER RIDGE OVER THE EASTERN US AND A SURFACE HIGH JUST OFF THE COAST
TO OUR SOUTHEAST. THIS PATTERN WILL ALLOW A SOUTHERLY WIND FLOW TO
STEADILY TRANSPORT WARMER AND MORE HUMID AIR INTO THE REGION AND GIVE
US INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. ANY SIGNIFICANT
DYNAMICS WILL BE KEPT AT BAY TO OUR WEST AND NORTH AS THEY RIDE UP AND
OVER THE RIDGE BUT OROGRAPHIC EFFECTS FROM THE BLUE RIDGE WESTWARD
SHOULD BE ENOUGH TO TRIGGER CONVECTION IN THE WARM/MOIST/UNSTABLE
AIRMASS WITH A TYPICAL DIURNAL BIAS. THE SEVERE THREAT LOOKS TO BE
MINIMAL BUT WITH PWATS RUNNING AROUND AN INCH AND A HALF LOCALLY HEAVY
DOWNPOURS WITH SLOW MOVING STORMS WILL BE SOMETHING TO CONTEND WITH. BY
MONDAY A COLD FRONT APPROACHING FROM THE WEST WILL BE ON OUR DOORSTEP.
INDICATIONS ARE THAT THE FRONT MAY DO A JUMP TO THE LEE TROF IN THE
PIEDMONT AND OVERALL BE A RATHER SLOPPY AND DIFFUSE FRONTAL PASSAGE.
THE LONG AND SHORT OF IT IS THAT WE CAN EXPECT WARM AND MUGGY
CONDITIONS WITH AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY
WITH THE BEST CHANCES BEING FROM THE BLUE RIDGE WESTWARD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 354 PM EDT WEDNESDAY...
MODELS IN PRETTY GOOD AGREEMENT THAT FRONT WILL PUSH THROUGH...OR
MORE LIKELY JUMP ACROSS INTO LEE TROUGH...OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. HOWEVER...THIS IS MORE OF A WIND SHIFT
LINE...WHILE TEMP AND MOISTURE GRADIENT STILL LAG BEHIND UNTIL LATER
TUESDAY. COULD SEE UPSLOPE-AIDED SHOWERS ON WESTERN SLOPES INTO AT
LEAST FIRST PART OF TUESDAY...AS WELL AS SOME SHOWERS OR EVEN
THUNDERSTORMS CLOSER TO THIS GRADIENT IN PIEDMONT LATER IN DAY.
PERHAPS NOT MUCH...IF ANYTHING...IN BETWEEN THOUGH. GIVEN TUESDAY
IS DAY 5...GOING TO KEEP CHANCE POP IN FOR ENTIRE AREA...BUT WITH
LOWEST VALUES IN THE MIDDLE...AND LIMIT THUNDER TO ISOLATED GIVEN
WHAT APPEARS TO BE VERY LIMITED INSTABILITY. COULD VERY WELL BE NO
THUNDER AT ALL AND IF FRONT ENDS UP BEING QUICKER MAY ALSO
EVENTUALLY NEED TO LOWER POPS TO LITTLE OR NOTHING FOR TUESDAY.
COOLER AND DRIER BEHIND FRONT FOR TUES NIGHT THROUGH WED NIGHT...AT
LEAST BY 5 TO 7 DEGREES...WITH SFC RIDGE BUILDING IN FROM
NORTH...AND THEN MORE OF A WEDGE SETTING IN FOR THURSDAY WITH
ELONGATED WEST-EAST SFC HIGH PRESSURE ACROSS OHIO VALLEY AND INTO
MID-ATLANTIC. MODELS HAVE SHOWN SOME SIGNS OF A WEAK UPPER WAVE
LIFTING OVER THIS FOR A CHANCE OF SHOWERS OR EVEN SOME LIGHT STEADY
RAIN...WITH THUNDER VERY UNLIKELY...BUT 12Z RUNS NOT SO
MUCH...ALTHOUGH GFS STILL HAS SOMETHING IN NW NC MTNS. TEMPTED TO
KEEP PRECIP CHANCES OUT ENTIRELY BUT GIVEN UNCERTAINTY IN THE LAST
COUPLE OF CYCLES AND BEING DAY 7...WILL HAVE A SLIGHT CHC TO LOW CHC
OF SHWRS...MAINLY WESTERN AND SOUTHERN PORTIONS. OVERRUNNING PRECIP
OR NOT WILL PLAY A ROLE IN TEMPERATURES AS WELL...AND HEDGING IT
DOWN A DEG OR TWO MORE FOR THURS FROM WED...BUT IF PRECIP LOOKS TO
BE A BETTER BET THAN THURS COULD BE MUCH COOLER IN MORE OF A CLASSIC
WEDGE.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AS OF 130 AM EDT FRIDAY...
SHORT WAVE OVER THE TENNESSEE VALLEY WILL MOVE EAST TODAY AND WILL
FLATTEN THE UPPER RIDGE OVER THE SOUTHEAST. SOUTHWEST FLOW ABOVE
THE SURFACE WILL CONTINUE TO TRANSPORT MOISTURE INTO THE REGION.
SATELLITE PICTURES ALREADY SHOWED EXTENSIVE HIGH CLOUD COVER. AT
THE SURFACE...SOUTHEAST WINDS MAY INCREASE ENOUGH FOR A LAYER OF
STRATOCUMULUS TO DEVELOP ALONG THE SOUTHERN APPALACHIANS.
MODERATE CONFIDENCE THERE WILL BE A SCATTERED TO BROKEN LAYER OF
CLOUDS WITH CEILINGS OF 3-5KFT. LOWER CONFIDENCE THAT THESE LOWER
CLOUDS WILL DEVELOP OVER KBCB/KDAN/KROA/KBLF.
MODELS HAVE BEEN CONSISTENT IN FORECAST OF LIGHT PRECIPITATION
JUST WEST OF THE MOUNTAINS. PROBABILITY STILL ENOUGH TO INCLUDE
SHOWERS IN THE VICINITY OF KLWB AND KBLF THIS AFTERNOON.
SATURDAY AND SUNDAY...THE MOISTURE IN COMBINATION WITH DAYTIME
HEATING WILL RESULT IN INSTABILITY DRIVEN SHOWERS AND
THUNDERSTORMS. THIS ACTIVITY IS EXPECTED TO BE SCATTERED AND NOT
ORGANIZED WITH BETTER COVERAGE OVER THE MOUNTAINS ON SUNDAY THAN
SATURDAY. SUB VFR CONDITIONS ARE CERTAINLY POSSIBLE WITH THE
SHOWERS AND THUNDERSTORMS...BUT OVERALL CONDITIONS WILL LIKELY
REMAIN VFR DUE TO THE SCATTERED NATURE OF THE ACTIVITY.
THE NEXT CHANCE FOR MORE WIDESPREAD AND ORGANIZED SHOWERS/STORMS
WILL BE WITH AHEAD OF A FRONT ON MONDAY AND WITH THE FRONTAL
PASSAGE ON TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...MBS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
854 PM CDT SAT MAY 16 2015
.UPDATE...PULLED TRIGGER ON DENSE FOG ADVY FOR MILWAUKEE...OZAUKEE
AND SHEBOYGAN COUNTIES. VISIBILITIES CRASHED EARLY THIS EVENING AS
DIURNAL MIXING ABATED AND SFC WINDS TURNED A BIT MORE NORTHEAST
PULLING DENSE FOG OVER LAKE INLAND. VISIBILITIES BOUNCING LAST
HOUR OR SO...BUT EXPECT AREAS OF DENSE FOG TO PERSIST ACROSS THE
LAKE SHORE COUNTIES FOR MUCH OF THE NIGHT. VISIBILITIES MAY
INCREASE LATER TONIGHT AS BOUNDARY LAYER WINDS BECOME MORE
SOUTHEAST AND INCREASE SLIGHTLY. MAY NEED TO EXPAND ADVY INTO
RACINE AND KENOSHA COUNTIES.
ISOLATED SHOWERS AND STORMS HAVE ENDED WITH LOSS OF DAYTIME
HEATING AND WEAK MID-LEVEL WAVE PASSING THRU. WL CONTINUE SMALL
CHANCE SPREADING IN FROM THE WEST LATER TONIGHT AHEAD OF
INCREASING LOW LEVEL MOISTURE CONVERGENCE AND LOW LEVEL JET.
BETTER CHANCE SUNDAY MORNING WITH STRONG TO SEVERE STORMS STILL
LIKELY IN THE AFTN AND EVE.
&&
.AVIATION/06Z TAFS/...BOUNDARY LAYER MIXING AND LOW LEVEL MOISTURE
CONVERGENCE SHOULD RESULT IN STRATUS DEVELOPING OVERNIGHT INTO
SUNDAY MORNING. FOG WILL CONTINUE TO CAUSE IFR OR LOWER VSBYS AT
KMKE...POSSIBLY AFFECTING KENW AND KUES. WL MAINTAIN BEST CHANCE
FOR T IN THE MID AFTN INTO THE EVE ON SUNDAY.
&&
.MARINE...DENSE FOG ADVY WILL CONTINUE INTO SUNDAY MORNING. LIGHT
SFC WINDS AND WARM...HUMID AIR OVER THE COLD LAKE MICHIGAN WATERS
WILL CONTINUE TO CAUSE DENSE FOG. LOW LEVEL WINDS WILL VEER TO THE
SOUTH TO SOUTHEAST LATER TONIGHT AND SUNDAY MORNING AND INCREASE
WHICH SHOULD HELP THIN THE FOG.
&&
.PREV DISCUSSION... /ISSUED 412 PM CDT SAT MAY 16 2015/
SHORT TERM...
TONIGHT THROUGH SUNDAY AFTERNOON...FORECAST CONFIDENCE MEDIUM.
WIDELY SCATTERED THUNDERSTORMS PERSIST THROUGH LATE AFTERNOON. THESE
ARE BEING TRIGGERED BY A WEAK MID LEVEL SHORTWAVE APPROACHING FROM
IA/IL. MODEL SOUNDINGS AND RAP SPC MESOSCALE ANALYSIS ARE SHOWING
TALL SKINNY CAPE VALUES OF 1000 TO 2000 J/KG INLAND FROM THE
LAKESHORE THIS AFTERNOON. THERE IS NOT MUCH SHEAR... SO ONLY BRIEF
SMALL HAIL WOULD BE POSSIBLE IN ANY STRONGER STORMS. THE MAIN THREAT
WILL BE BRIEF HEAVY RAIN SINCE PRECIPITABLE WATER VALUES ARE AROUND
1.3 INCHES TODAY.
THESE THUNDERSTORMS WILL DIMINISH AFTER SUNSET THIS EVENING. LIGHT
WINDS AND SMALL DEWPOINT DEPRESSIONS WILL LEAD TO PATCHY FOG AND LOW
CLOUDS ACROSS SOUTHERN WI OVERNIGHT. THERE IS A CHANCE THAT MARINE
FOG WILL SPREAD INLAND ONCE AGAIN. THE CLOUDS WILL LIKELY LINGER
INTO THE MID SUNDAY MORNING HOURS.
SURFACE LOW PRESSURE OVER THE DAKOTAS WILL TRACK INTO MINNESOTA
TONIGHT AND STALL THROUGH SUNDAY AS IT OCCLUDES. THE 850 MB WARM
CONVEYOR BELT... OR WARM MOIST AIR TRANSPORT... WILL LIFT THROUGH
SOUTHERN WI SUNDAY MORNING INTO THE EARLY AFTERNOON. THIS WILL BRING
A BAND OF NUMEROUS SHOWERS AND THUNDERSTORMS THAT SHOULD MARCH
NORTHEAST ACROSS SOUTH CENTRAL AND SOUTHEAST WI. THERE IS SOME
CONCERN THAT AN EMBEDDED THUNDERSTORM COULD BECOME SEVERE DURING THE
AFTERNOON AS THE ATMOSPHERE BECOMES LESS STABLE. MODELS ARE HINTING
AT SOUTHEAST WI AND LAKE MICHIGAN HAVING THE GREATEST THREAT FOR
ENHANCED THUNDERSTORMS ON THE BACK EDGE OF THIS FIRST ROUND.
TEMPERATURES WILL RISE INTO THE UPPER 70S... SIMILAR TO TODAY.
LAKESHORE TEMPS WILL BE A LITTLE COOLER THAN INLAND GIVEN A SLIGHT
EASTERLY COMPONENT. WINDS WILL BE STRONG OUT OF THE SOUTH DUE TO A
TIGHT PRESSURE GRADIENT WITH THE APPROACHING SURFACE LOW.
LATE SUNDAY AFTERNOON THROUGH TUESDAY...FORECAST CONFIDENCE
MEDIUM.
THE OCCLUDED LOW OVER NW MN WILL WEAKEN TO A BROAD W-E SFC TROUGH
STARTING LATE SUNDAY NIGHT AND THROUGH MONDAY AS IT MOVES ACROSS
LAKE SUPERIOR AND INTO CANADA. BEFORE IT WEAKENS...THE PASSAGE OF
A TRAILING UPPER TROUGH AXIS AND A PREFRONTAL SFC TROUGH WILL
LIKELY INITIATE A NEW ROUND OF SCATTERED CONVECTION LATE SUNDAY
AFTERNOON AND THROUGH THE EVENING. THE NAM AND SOME MESOMODELS
ARE SHOWING WHAT WILL LIKELY BE DISCRETE SUPERCELLS DEVELOPING
FROM THE MS RIVER EWD. A 60-65 KT 500 MB JET STREAK WILL
ACCOMPANY THE UPPER WAVE...SUPPORTING 0-6 KM BULK SHEAR OF 50
KTS AND A SUPERCELL POTENTIAL WITH MLCAPE VALUES UP TO 1500 J/KG
OVER SOUTH CENTRAL WI. A TORNADO RISK WILL BE PRESENT DUE TO
0-1 KM SRH OF 150-200 M2/S2 AND 0-1 KM BULK SHEAR RISING TO 25
KTS. LCL HEIGHTS WILL ALSO BE AT OR BELOW 1 KM WITH THE LFC ONLY
SLIGHTLY HIGHER. SPC HAS UPGRADED TO AN ENHANCED RISK OF SEVERE
TSTORMS OVER MUCH OF WESTERN AND CENTRAL WI...MENTIONING THE
POSSIBILITY OF STRONG TORNADOES. CAPE VALUES WILL REMAIN BELOW
1000 J/KG OVER ERN WI AND THE STORMS MAY NOT ARRIVE UNTIL THE
MIDDLE TO LATE EVENING...THUS THE SLIGHT RISK THERE. HOWEVER SHEAR
VALUES DO BECOME STRONG AS WELL.
THE ACTUAL COLD FRONT WILL GRADUAL MOVE ACROSS SRN WI ON
MONDAY...THUS 70 DEGREE HIGHS ARE EXPECTED. NWLY FLOW AND COLD
ADVECTION WILL THEN PREVAIL FOR MONDAY NIGHT AND TUESDAY. SRN WI
APPEARS TO BE FAR ENOUGH SOUTH TO AVOID THE BROKEN STRATUS ON
MONDAY BUT SOME STRATUS WILL BE POSSIBLE MONDAY NIGHT INTO
TUESDAY. A CANADIAN AIRMASS AND LINGERING CLOUDS INTO TUE
AFTERNOON WILL KEEP HIGH TEMPS ONLY IN THE 50S.
LONG TERM...
TUESDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM.
A LARGE SFC HIGH WILL EXTEND FROM THE GREAT PLAINS TOWARD THE OHIO
RIVER VALLEY FOR THIS PERIOD. A RELATIVELY WEAK WNWLY FLOW ALOFT
WILL PREVAIL WITH BELOW NORMAL TEMPS EXPECTED IN THE BEGINNING OF
THE PERIOD BUT QUICKLY REBOUND TO SEASONAL NORMALS. NO PCPN IS
EXPECTED.
AVIATION/00Z TAFS/...
DENSE MARINE FOG MAY SPREAD INLAND TO KMKE AND KRAC LATE THIS
AFTERNOON. WILL NOT ADD INTO THE MKE TAF YET... BUT BE AWARE FOR THE
POTENTIAL. DENSE FOG WILL BE A POSSIBILITY ONCE AGAIN AT KSBM...
KMKE... KRAC AND KENW TONIGHT.
SHOWERS DISSIPATED THIS MORNING. MVFR CUMULUS CLOUDS ARE DEVELOPING
FROM SOUTH TO NORTH EARLY THIS AFTERNOON. A FEW WIDELY SCATTERED
THUNDERSTORMS WILL BE POSSIBLE ACROSS SOUTHERN WI THIS AFTERNOON.
SMALL HAIL IS POSSIBLE FROM MADISON AND WEST... BUT BRIEF PERIODS OF
HEAVY RAIN IS THE MAIN THREAT.
LOOK FOR A PERIOD OF SHOWERS AND THUNDERSTORMS TO TRACK ACROSS SOUTH
CENTRAL AND SOUTHEAST WI MIDDAY SUNDAY INTO SUNDAY AFTERNOON. THERE
IS A CHANCE FOR ISOLATED SEVERE THUNDERSTORMS LATE SUNDAY AFTERNOON
AND SUNDAY EVENING.
MARINE...
A MARINE DENSE FOG ADVISORY FOR ALL OF THE NSH ZONES IS IN EFFECT
UNTIL 15Z SUNDAY. NOT ANTICIPATING MUCH CHANGE IN CONDITIONS DUE TO
LIGHT WINDS ALLOWING FOR DENSE FOG TO CONTINUE OVER THE COOL LAKE
WATERS.
SOUTHERLY WINDS WILL APPROACH SMALL CRAFT ADVISORY LEVELS SUNDAY
AFTERNOON AS LOW PRESSURE STALLS OVER MINNESOTA. EXPECTING WINDS AND
WAVES TO REMAIN JUST BELOW CRITERIA SO NO HEADLINE AT THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 10 AM CDT SUNDAY FOR WIZ052-060-066.
LM...DENSE FOG ADVISORY UNTIL 10 AM CDT SUNDAY FOR LMZ643>646.
&&
$$
UPDATE...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1258 PM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI MAY 15 2015
BIGGEST CHANGE TO THIS PERIOD WILL BE TO REMOVE THE SEVERE STORM
POTENTIAL OVERNIGHT CURRENTLY IN THE SERVICE SUITE.
SATELLITE AND SURFACE OBSERVATIONS SHOWING A VERY WEAK PRESSURE
GRADIENT AND LOW CLOUD AND FOG FAIRLY WIDESPREAD ACROSS THE
REGION IN THE WAKE OF THE RAIN. STILL SOME DRIZZLE BEING REPORTED
IN WI IN WHAT THE RAP SOUNDINGS INDICATE AS A 2KM DEEP MOIST
LAYER. SPORADIC REPORTS OF NEAR ZERO VISIBILITY ARE OUT THERE AS
OF 08Z /MAINLY IOWA/...BUT WEB CAMERAS ACROSS THE AREA DONT REVEAL
WIDESPREAD REDUCTIONS TO VISIBILITY. OVERALL IDEA TODAY IS
SHORTWAVE RIDGING BUILDING IN AND DEEPER MIXING...BUT HAVE TAKEN A
PESSIMISTIC APPROACH WITH MORE SUN SEEN IN THE AFTERNOON. WILL
CONTINUE TO MONITOR FOR MORE WIDESPREAD FOG ISSUES AND FOR NOW
WILL HANDLE THIS WITH SPECIAL WX STATEMENTS.
PREVIOUS FORECAST AND CURRENT MESSAGING CONTAINS A SEVERE RISK
OVERNIGHT AS THE WARM FRONT...NOW LOCATED ROUGHLY ALONG
I-80...LIFTS INTO THE AREA. A SECONDARY MARITIME TROPICAL AIRMASS
RESIDES SOUTH OF I-70 WITH 65-70F DEWPOINTS...NOT TOO FAR AWAY.
THE 15.00Z NAM IS REALLY THE OUTLIER ON THE MUCAPE FORECAST INTO
THE AREA /THROUGH ITS ENTIRE FORECAST/ AND FEEL IT MUST BE REDUCED
ABOUT 30 PERCENT BASED ON SOUNDINGS AND LATEST MODEL CONSENSUS. AS
THE SPOKE OF ENERGY FROM THE SWRN U.S. LONG WAVE TROUGH ROTATES
NORTH //NOW IN NM/AZ//...HEIGHTS WILL FALL IN THE LOW-LEVELS AND
THE MOISTURE TRANSPORT WILL ENHANCE IN THE DAKOTAS/WRN MN...BUT
PRETTY FAR WEST. BY THE THE OVERNIGHT HOURS...AN AXIS OF MOISTURE
CONVERGENCE AND ABOUT 500 J/KG OF MUCAPE WILL RUN FROM KABR-KLSE.
BETTER CONVERGENCE ALONG THE WARM FRONT IN THE LOW LEVELS WILL BE
OCCURRING FURTHER WEST. HAVE KEPT 30S PERCENT CHANCES FOR THAT
PERIOD FOR THUNDERSTORMS...BUT THE WIND SHEAR IS VERY LOW AND THE
LESS AGGRESSIVE MODELS WITH MOISTURE /15.00Z GFS/ SUGGEST SOME
CAPPING OF 50-80J IS IN PLACE FOR 1-2KM PARCELS BEING LIFTED. SO
COVERAGE OF STORMS IS ALSO IN QUESTION. OVERALL...DIDNT SEE AN
ORGANIZED THREAT TO SPEAK OF FOR MESSAGING IN OUR SERVICE. WILL BE
PULLING THAT MENTION. SPC DAY 1 OUTLOOK WOULD AGREE WITH THIS
ASSESSMENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI MAY 15 2015
SATURDAY WILL SEE WARMER CONDITIONS AS THE WARM FRONT SHIFTS FURTHER
NORTH INTO THE NORTHERN FORECAST AREA AND NRN WI. DEWPOINTS AND
CAPE WILL BE ON THE INCREASE AND PROBABLY ABOUT 1000 J/KG OF
MLCAPE WILL BE PRESENT IN THE AFTERNOON. HOWEVER...FORCING IS
MINIMAL DURING PEAK HEATING WITH FAIRLY UNIFORM S-SE FLOW IN THE
FORECAST AREA IN THE WARM SECTOR. THE WILD CARD MAY BE ANY
CONVECTIVE VORTICITY THAT IS GENERATED IN THE SRLY FLOW. HAVE LEFT
SMALL RAIN CHANCES IN THE AFTERNOON. IT COULD BE A WARM DAY
SATURDAY AND BUMPED HIGHS A BIT WITH 19-21C SUGGESTED AT 925MB
FROM THE 15.00Z GUIDANCE /4-5C WARMER THAN FRIDAY/.
THE BIG STORY CONTINUES TO BE THE SUNDAY POTENTIAL FOR SEVERE
STORMS. POTENTIAL IS A GOOD WORD AS IT COULD BE A FAVORABLE DAY
FOR TORNADOES...BUT ALSO COULD RAIN THROUGH THE MORNING AND TURN
INTO NO STORY. THERE IS A BIG DIFFERENCE BETWEEN THE
DETERMINISTIC GUIDANCE WITH THE 15.00Z AND 14.18Z NAM RUNS SUGGESTING
A GOOD SETUP FOR SUPERCELL TORNADOES AND THE OVERALL SYNOPTICS AND
TIMING. HOWEVER...IT IS AN OUTLIER AS THE 15.00Z ECMWF/GFS AND
15.03Z/21Z SREFS ALL SUGGEST A DIFFERENT OUTCOME. THAT OUTCOME
WOULD INCLUDE STRONG MOISTURE TRANSPORT CONVERGENCE COMING INTO
THE AREA EARLY ON SUNDAY FROM THE WEST /SUNRISE/ AND SHIFTING EAST
ACROSS THE AREA. THERE WOULD PROBABLY BE ENOUGH INSTABILITY AND
INCREASING DEEPER STRONGER SHEAR FOR SOME MARGINALLY SEVERE
STORMS THEN. POSSIBLY A SMALL WINDOW IN WI FOR SEVERE STORMS TO
REDEVELOP LATER...BUT THIS SEEMS TO SHIFT NORTHEAST QUICKLY. THE
SLOWER 15.00Z AND 14.18Z NAM RUNS SUGGEST A SLOWER TIMING AND LESS
MORNING CONVECTION INTO WI...FAVORING A BETTER SUNDAY AFTERNOON
SEVERE STORM OUTBREAK.
IMPORTANTLY...SUNDAY HAS EXCELLENT DEEP SHEAR THROUGH 10KM...AND
TIMING AND INSTABILITY ARE THE MAIN PROBLEMS THAT NEED RESOLUTION. SPC
DAY 3 DISCUSSION MAINTAINS THE SLIGHT RISK OVER THE AREA...WHICH
SEEMS ON TRACK FOR THE DIFFERENCES THAT REMAIN ON SUNDAYS OUTCOME.
IT IS ONLY FRIDAY MORNING...AND THESE SWRN U.S. SYSTEMS ARE VERY
DEPENDENT ON THE ENERGY OVER THE PACIFIC BEING RESOLVED CORRECTLY
BY THE MODEL INITIALIZATION. THE NAM SKILL IN THE OUTER HOURS IS
NOT AS FAVORABLE AS WITHIN A DAY. WILL TRY TO STRESS THAT
DIFFERENCES EXIST ON HOW SUNDAY COULD PLAY OUT...BUT THAT A RISK
OF ORGANIZED SEVERE WEATHER EXISTS.
MONDAY THROUGH THURSDAY...AFTER THIS DEEPENING LOW AND SHOWER
CHANCES SHIFT EAST...THE WEEK SHOULD HAVE SLIGHTLY BELOW NORMAL
TEMPERATURES AND MAINLY DRY UNDER CONFLUENT NORTHWEST FLOW AND
CANADIAN SOURCED HIGH PRESSURE. COLDEST DAYS WILL BE MONDAY AND
TUESDAY...THEN SOME RISE EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1258 PM CDT FRI MAY 15 2015
MVFR STRATUS WILL SCATTER OUT LATE THIS AFTERNOON WITH CLOUD
BASES IN THE 1800 TO 2500 FT RANGE. INCREASING MOISTURE ACROSS THE
REGION WILL PRODUCE BR LATE TONIGHT WITH THE POTENTIAL TO SEE
SOME PATCHY FOG AT TIMES. PLAN ON VISIBILITIES FALLING TO AROUND
3SM AT KRST AND 4SM AT KLSE AFTER MIDNIGHT. LOWER VISIBILITIES ARE
POSSIBLE. AFTER THE FOG DISSIPATES SATURDAY MORNING PLAN ON
SCATTERED CUMULUS FOR THE MID TO LATE MORNING HOURS WITH THE
CHANCE OF SEEING AN ISOLATED THUNDERSTORM OR TWO.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BAUMGARDT
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
622 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI MAY 15 2015
BIGGEST CHANGE TO THIS PERIOD WILL BE TO REMOVE THE SEVERE STORM
POTENTIAL OVERNIGHT CURRENTLY IN THE SERVICE SUITE.
SATELLITE AND SURFACE OBSERVATIONS SHOWING A VERY WEAK PRESSURE
GRADIENT AND LOW CLOUD AND FOG FAIRLY WIDESPREAD ACROSS THE
REGION IN THE WAKE OF THE RAIN. STILL SOME DRIZZLE BEING REPORTED
IN WI IN WHAT THE RAP SOUNDINGS INDICATE AS A 2KM DEEP MOIST
LAYER. SPORADIC REPORTS OF NEAR ZERO VISIBILITY ARE OUT THERE AS
OF 08Z /MAINLY IOWA/...BUT WEB CAMERAS ACROSS THE AREA DONT REVEAL
WIDESPREAD REDUCTIONS TO VISIBILITY. OVERALL IDEA TODAY IS
SHORTWAVE RIDGING BUILDING IN AND DEEPER MIXING...BUT HAVE TAKEN A
PESSIMISTIC APPROACH WITH MORE SUN SEEN IN THE AFTERNOON. WILL
CONTINUE TO MONITOR FOR MORE WIDESPREAD FOG ISSUES AND FOR NOW
WILL HANDLE THIS WITH SPECIAL WX STATEMENTS.
PREVIOUS FORECAST AND CURRENT MESSAGING CONTAINS A SEVERE RISK
OVERNIGHT AS THE WARM FRONT...NOW LOCATED ROUGHLY ALONG
I-80...LIFTS INTO THE AREA. A SECONDARY MARITIME TROPICAL AIRMASS
RESIDES SOUTH OF I-70 WITH 65-70F DEWPOINTS...NOT TOO FAR AWAY.
THE 15.00Z NAM IS REALLY THE OUTLIER ON THE MUCAPE FORECAST INTO
THE AREA /THROUGH ITS ENTIRE FORECAST/ AND FEEL IT MUST BE REDUCED
ABOUT 30 PERCENT BASED ON SOUNDINGS AND LATEST MODEL CONSENSUS. AS
THE SPOKE OF ENERGY FROM THE SWRN U.S. LONG WAVE TROUGH ROTATES
NORTH //NOW IN NM/AZ//...HEIGHTS WILL FALL IN THE LOW-LEVELS AND
THE MOISTURE TRANSPORT WILL ENHANCE IN THE DAKOTAS/WRN MN...BUT
PRETTY FAR WEST. BY THE THE OVERNIGHT HOURS...AN AXIS OF MOISTURE
CONVERGENCE AND ABOUT 500 J/KG OF MUCAPE WILL RUN FROM KABR-KLSE.
BETTER CONVERGENCE ALONG THE WARM FRONT IN THE LOW LEVELS WILL BE
OCCURRING FURTHER WEST. HAVE KEPT 30S PERCENT CHANCES FOR THAT
PERIOD FOR THUNDERSTORMS...BUT THE WIND SHEAR IS VERY LOW AND THE
LESS AGGRESSIVE MODELS WITH MOISTURE /15.00Z GFS/ SUGGEST SOME
CAPPING OF 50-80J IS IN PLACE FOR 1-2KM PARCELS BEING LIFTED. SO
COVERAGE OF STORMS IS ALSO IN QUESTION. OVERALL...DIDNT SEE AN
ORGANIZED THREAT TO SPEAK OF FOR MESSAGING IN OUR SERVICE. WILL BE
PULLING THAT MENTION. SPC DAY 1 OUTLOOK WOULD AGREE WITH THIS
ASSESSMENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI MAY 15 2015
SATURDAY WILL SEE WARMER CONDITIONS AS THE WARM FRONT SHIFTS FURTHER
NORTH INTO THE NORTHERN FORECAST AREA AND NRN WI. DEWPOINTS AND
CAPE WILL BE ON THE INCREASE AND PROBABLY ABOUT 1000 J/KG OF
MLCAPE WILL BE PRESENT IN THE AFTERNOON. HOWEVER...FORCING IS
MINIMAL DURING PEAK HEATING WITH FAIRLY UNIFORM S-SE FLOW IN THE
FORECAST AREA IN THE WARM SECTOR. THE WILD CARD MAY BE ANY
CONVECTIVE VORTICITY THAT IS GENERATED IN THE SRLY FLOW. HAVE LEFT
SMALL RAIN CHANCES IN THE AFTERNOON. IT COULD BE A WARM DAY
SATURDAY AND BUMPED HIGHS A BIT WITH 19-21C SUGGESTED AT 925MB
FROM THE 15.00Z GUIDANCE /4-5C WARMER THAN FRIDAY/.
THE BIG STORY CONTINUES TO BE THE SUNDAY POTENTIAL FOR SEVERE
STORMS. POTENTIAL IS A GOOD WORD AS IT COULD BE A FAVORABLE DAY
FOR TORNADOES...BUT ALSO COULD RAIN THROUGH THE MORNING AND TURN
INTO NO STORY. THERE IS A BIG DIFFERENCE BETWEEN THE
DETERMINISTIC GUIDANCE WITH THE 15.00Z AND 14.18Z NAM RUNS SUGGESTING
A GOOD SETUP FOR SUPERCELL TORNADOES AND THE OVERALL SYNOPTICS AND
TIMING. HOWEVER...IT IS AN OUTLIER AS THE 15.00Z ECMWF/GFS AND
15.03Z/21Z SREFS ALL SUGGEST A DIFFERENT OUTCOME. THAT OUTCOME
WOULD INCLUDE STRONG MOISTURE TRANSPORT CONVERGENCE COMING INTO
THE AREA EARLY ON SUNDAY FROM THE WEST /SUNRISE/ AND SHIFTING EAST
ACROSS THE AREA. THERE WOULD PROBABLY BE ENOUGH INSTABILITY AND
INCREASING DEEPER STRONGER SHEAR FOR SOME MARGINALLY SEVERE
STORMS THEN. POSSIBLY A SMALL WINDOW IN WI FOR SEVERE STORMS TO
REDEVELOP LATER...BUT THIS SEEMS TO SHIFT NORTHEAST QUICKLY. THE
SLOWER 15.00Z AND 14.18Z NAM RUNS SUGGEST A SLOWER TIMING AND LESS
MORNING CONVECTION INTO WI...FAVORING A BETTER SUNDAY AFTERNOON
SEVERE STORM OUTBREAK.
IMPORTANTLY...SUNDAY HAS EXCELLENT DEEP SHEAR THROUGH 10KM...AND
TIMING AND INSTABILITY ARE THE MAIN PROBLEMS THAT NEED RESOLUTION. SPC
DAY 3 DISCUSSION MAINTAINS THE SLIGHT RISK OVER THE AREA...WHICH
SEEMS ON TRACK FOR THE DIFFERENCES THAT REMAIN ON SUNDAYS OUTCOME.
IT IS ONLY FRIDAY MORNING...AND THESE SWRN U.S. SYSTEMS ARE VERY
DEPENDENT ON THE ENERGY OVER THE PACIFIC BEING RESOLVED CORRECTLY
BY THE MODEL INITIALIZATION. THE NAM SKILL IN THE OUTER HOURS IS
NOT AS FAVORABLE AS WITHIN A DAY. WILL TRY TO STRESS THAT
DIFFERENCES EXIST ON HOW SUNDAY COULD PLAY OUT...BUT THAT A RISK
OF ORGANIZED SEVERE WEATHER EXISTS.
MONDAY THROUGH THURSDAY...AFTER THIS DEEPENING LOW AND SHOWER
CHANCES SHIFT EAST...THE WEEK SHOULD HAVE SLIGHTLY BELOW NORMAL
TEMPERATURES AND MAINLY DRY UNDER CONFLUENT NORTHWEST FLOW AND
CANADIAN SOURCED HIGH PRESSURE. COLDEST DAYS WILL BE MONDAY AND
TUESDAY...THEN SOME RISE EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 622 AM CDT FRI MAY 15 2015
MVFR/IFR CIGS/VSBYS ACROSS THE AREA EXPECTED TO GIVE WAY TO VFR
CONDITIONS THRU THE MORNING AS SOME DRYING NORTHWEST LOW LEVEL
FLOW...DIURNAL WARMING/MIXING AND A SFC-850MB RIDGE AXIS MOVES OVER
MN/WI. SCT MAINLY VFR LOWER CLOUDS EXPECTED BY EARLY AFTERNOON...
UNDER A BKN-OVC CIRRUS DECK. CIRRUS DECK SET TO THICKEN TONIGHT...
AND LOOKS TO HELP KEEP LOWER CLOUDS MORE SCT THRU TONIGHT. LOWER
MOISTURE DOES INCREASE LATER TONIGHT AS A WARM FRONT LIFTS NORTH
TOWARD THE TAF SITES AND LOWER LEVEL WINDS SWING BACK TO THE
SOUTHEAST. MAY BE SOME SHRA/TSRA IN THE AREA LATE TONIGHT AS THE
WARM FRONT APPROACHES. HOWEVER...WITH ONLY ISOLATED TO WIDELY SCT
COVERAGE EXPECTED AND CONFIDENCE IN ANY SHRA/TSRA CHANCES LATE
TONIGHT NOT THE HIGHEST...LEFT MENTION OF THEM OUT OF THE LAST 3 TO
6 HRS OF THE TAF FOR NOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BAUMGARDT
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 AM CDT FRI MAY 15 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI MAY 15 2015
BIGGEST CHANGE TO THIS PERIOD WILL BE TO REMOVE THE SEVERE STORM
POTENTIAL OVERNIGHT CURRENTLY IN THE SERVICE SUITE.
SATELLITE AND SURFACE OBSERVATIONS SHOWING A VERY WEAK PRESSURE
GRADIENT AND LOW CLOUD AND FOG FAIRLY WIDESPREAD ACROSS THE
REGION IN THE WAKE OF THE RAIN. STILL SOME DRIZZLE BEING REPORTED
IN WI IN WHAT THE RAP SOUNDINGS INDICATE AS A 2KM DEEP MOIST
LAYER. SPORADIC REPORTS OF NEAR ZERO VISIBILITY ARE OUT THERE AS
OF 08Z /MAINLY IOWA/...BUT WEB CAMERAS ACROSS THE AREA DONT REVEAL
WIDESPREAD REDUCTIONS TO VISIBILITY. OVERALL IDEA TODAY IS
SHORTWAVE RIDGING BUILDING IN AND DEEPER MIXING...BUT HAVE TAKEN A
PESSIMISTIC APPROACH WITH MORE SUN SEEN IN THE AFTERNOON. WILL
CONTINUE TO MONITOR FOR MORE WIDESPREAD FOG ISSUES AND FOR NOW
WILL HANDLE THIS WITH SPECIAL WX STATEMENTS.
PREVIOUS FORECAST AND CURRENT MESSAGING CONTAINS A SEVERE RISK
OVERNIGHT AS THE WARM FRONT...NOW LOCATED ROUGHLY ALONG
I-80...LIFTS INTO THE AREA. A SECONDARY MARITIME TROPICAL AIRMASS
RESIDES SOUTH OF I-70 WITH 65-70F DEWPOINTS...NOT TOO FAR AWAY.
THE 15.00Z NAM IS REALLY THE OUTLIER ON THE MUCAPE FORECAST INTO
THE AREA /THROUGH ITS ENTIRE FORECAST/ AND FEEL IT MUST BE REDUCED
ABOUT 30 PERCENT BASED ON SOUNDINGS AND LATEST MODEL CONSENSUS. AS
THE SPOKE OF ENERGY FROM THE SWRN U.S. LONG WAVE TROUGH ROTATES
NORTH //NOW IN NM/AZ//...HEIGHTS WILL FALL IN THE LOW-LEVELS AND
THE MOISTURE TRANSPORT WILL ENHANCE IN THE DAKOTAS/WRN MN...BUT
PRETTY FAR WEST. BY THE THE OVERNIGHT HOURS...AN AXIS OF MOISTURE
CONVERGENCE AND ABOUT 500 J/KG OF MUCAPE WILL RUN FROM KABR-KLSE.
BETTER CONVERGENCE ALONG THE WARM FRONT IN THE LOW LEVELS WILL BE
OCCURRING FURTHER WEST. HAVE KEPT 30S PERCENT CHANCES FOR THAT
PERIOD FOR THUNDERSTORMS...BUT THE WIND SHEAR IS VERY LOW AND THE
LESS AGGRESSIVE MODELS WITH MOISTURE /15.00Z GFS/ SUGGEST SOME
CAPPING OF 50-80J IS IN PLACE FOR 1-2KM PARCELS BEING LIFTED. SO
COVERAGE OF STORMS IS ALSO IN QUESTION. OVERALL...DIDNT SEE AN
ORGANIZED THREAT TO SPEAK OF FOR MESSAGING IN OUR SERVICE. WILL BE
PULLING THAT MENTION. SPC DAY 1 OUTLOOK WOULD AGREE WITH THIS
ASSESSMENT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI MAY 15 2015
SATURDAY WILL SEE WARMER CONDITIONS AS THE WARM FRONT SHIFTS FURTHER
NORTH INTO THE NORTHERN FORECAST AREA AND NRN WI. DEWPOINTS AND
CAPE WILL BE ON THE INCREASE AND PROBABLY ABOUT 1000 J/KG OF
MLCAPE WILL BE PRESENT IN THE AFTERNOON. HOWEVER...FORCING IS
MINIMAL DURING PEAK HEATING WITH FAIRLY UNIFORM S-SE FLOW IN THE
FORECAST AREA IN THE WARM SECTOR. THE WILD CARD MAY BE ANY
CONVECTIVE VORTICITY THAT IS GENERATED IN THE SRLY FLOW. HAVE LEFT
SMALL RAIN CHANCES IN THE AFTERNOON. IT COULD BE A WARM DAY
SATURDAY AND BUMPED HIGHS A BIT WITH 19-21C SUGGESTED AT 925MB
FROM THE 15.00Z GUIDANCE /4-5C WARMER THAN FRIDAY/.
THE BIG STORY CONTINUES TO BE THE SUNDAY POTENTIAL FOR SEVERE
STORMS. POTENTIAL IS A GOOD WORD AS IT COULD BE A FAVORABLE DAY
FOR TORNADOES...BUT ALSO COULD RAIN THROUGH THE MORNING AND TURN
INTO NO STORY. THERE IS A BIG DIFFERENCE BETWEEN THE
DETERMINISTIC GUIDANCE WITH THE 15.00Z AND 14.18Z NAM RUNS SUGGESTING
A GOOD SETUP FOR SUPERCELL TORNADOES AND THE OVERALL SYNOPTICS AND
TIMING. HOWEVER...IT IS AN OUTLIER AS THE 15.00Z ECMWF/GFS AND
15.03Z/21Z SREFS ALL SUGGEST A DIFFERENT OUTCOME. THAT OUTCOME
WOULD INCLUDE STRONG MOISTURE TRANSPORT CONVERGENCE COMING INTO
THE AREA EARLY ON SUNDAY FROM THE WEST /SUNRISE/ AND SHIFTING EAST
ACROSS THE AREA. THERE WOULD PROBABLY BE ENOUGH INSTABILITY AND
INCREASING DEEPER STRONGER SHEAR FOR SOME MARGINALLY SEVERE
STORMS THEN. POSSIBLY A SMALL WINDOW IN WI FOR SEVERE STORMS TO
REDEVELOP LATER...BUT THIS SEEMS TO SHIFT NORTHEAST QUICKLY. THE
SLOWER 15.00Z AND 14.18Z NAM RUNS SUGGEST A SLOWER TIMING AND LESS
MORNING CONVECTION INTO WI...FAVORING A BETTER SUNDAY AFTERNOON
SEVERE STORM OUTBREAK.
IMPORTANTLY...SUNDAY HAS EXCELLENT DEEP SHEAR THROUGH 10KM...AND
TIMING AND INSTABILITY ARE THE MAIN PROBLEMS THAT NEED RESOLUTION. SPC
DAY 3 DISCUSSION MAINTAINS THE SLIGHT RISK OVER THE AREA...WHICH
SEEMS ON TRACK FOR THE DIFFERENCES THAT REMAIN ON SUNDAYS OUTCOME.
IT IS ONLY FRIDAY MORNING...AND THESE SWRN U.S. SYSTEMS ARE VERY
DEPENDENT ON THE ENERGY OVER THE PACIFIC BEING RESOLVED CORRECTLY
BY THE MODEL INITIALIZATION. THE NAM SKILL IN THE OUTER HOURS IS
NOT AS FAVORABLE AS WITHIN A DAY. WILL TRY TO STRESS THAT
DIFFERENCES EXIST ON HOW SUNDAY COULD PLAY OUT...BUT THAT A RISK
OF ORGANIZED SEVERE WEATHER EXISTS.
MONDAY THROUGH THURSDAY...AFTER THIS DEEPENING LOW AND SHOWER
CHANCES SHIFT EAST...THE WEEK SHOULD HAVE SLIGHTLY BELOW NORMAL
TEMPERATURES AND MAINLY DRY UNDER CONFLUENT NORTHWEST FLOW AND
CANADIAN SOURCED HIGH PRESSURE. COLDEST DAYS WILL BE ONDAY AND
TUESDAY...THEN SOME RISE EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1110 PM CDT THU MAY 14 2015
CIGS...
MVFR/IFR ARE EXPECTED INTO FRIDAY MORNING. BUFKIT SOUNDINGS
SUGGEST A DECREASE IN THE LOW SATURATION AS MIXING AND SINKING AIR
START TO ENTRAIN SOME DRIER AIR. PREVIOUSLY...IT APPEARED THERE
COULD BE A BREAK INTO SCT SKIES BY EARLY TO MID AFTERNOON - AFTER
18Z FRI. HOWEVER...LATEST RAP/NAM12 BUFKIT SOUNDINGS SUGGESTING THIS
COULD OCCUR A FEW HOURS EARLIER. WILL REFINE FORECAST A BIT TOWARD
THIS. ANOTHER ROUND OF MVFR CIGS LOOKS POSSIBLE AS A WARM FRONT
LIFTS NORTHWARD ACROSS THE REGION OVERNIGHT FRIDAY.
WX/VSBY...
AREA OF SHOWERS MAKING STEADY PROGRESS NORTHEAST LATE
THIS EVENING. THEY HAVE ALREADY CLEARED KRST AND WILL PUSH PAST KLSE
BEFORE 06Z. VSBY RESTRICTIONS SHOULD PERSIST INTO THE OVERNIGHT
HOURS FROM FOG DUE TO THE COMPLETED RAINFALL AND SATURATED AIRMASS.
NUMERICAL GUIDANCE BRINGS CONFIDENCE DOWN A BIT THOUGH...POINTING TO
MUCH QUICKER IMPROVEMENT - ESPECIALLY AT KLSE. WILL KEEP AT LEAST
MVFR VSBY UNTIL BOUNDARY SWINGS WINDS TO A WESTERLY DIRECTION.
WINDS...
UPPER LEVEL SHORTWAVE TROUGH LIFTS NORTHEAST ACROSS THE
REGION TONIGHT...TAKING A SFC FRONT WITH IT. WINDS SHOULD SWITCH
FROM SOUTHEAST TO WESTERLY OVERNIGHT/EARLY FRI MORNING. LIKELY
BECOMES A BIT VARIABLE FOR FRIDAY NIGHT - GRADUALLY RETURNING TO THE
SOUTHEAST AS THE WARM FRONT MOVES THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
557 AM MDT FRI MAY 15 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT FRI MAY 15 2015
SHOWERS AND A FEW STRONG THUNDERSTORMS HAVE BEEN ONGOING FOR MUCH OF
THE NIGHT OVER THE PLAINS. THIS IS IN RESPONSE TO STRONG LLVL THETA-
E ADVECTION NORTH OF A STATIONARY BOUNDARY DRAPED FROM WEST TO EAST
ALONG THE I-80 CORRIDOR. BUFKIT SOUNDINGS FROM THE RAP MODEL SHOW UP
TO 500 J/KG OF MUCAPE TO THE NORTH OF THIS BOUNDARY...WHICH COMBINED
WITH MODEST DEEP LAYER VERTICAL SHEAR IS CONTRIBUTING TO SOME SMALL
HAIL PRODUCTION. ISSUED A FEW SPS PRODUCTS THIS MORNING TO HIGHLIGHT
THE STRONGEST CELLS...BUT EVERYTHING IS STAYING SUB-SEVERE. AIR MASS
ACROSS MUCH OF SOUTHEAST WYO/WESTERN NEB IS BECOMING VERY MOIST THIS
MORNING WITH LLVL EASTERLY/UPSLOPE FLOW. DEWPOINTS OVER WESTERN NEB
WERE ALREADY IN THE 50-55 F RANGE AT 10Z...AND THESE ARE EXPECTED TO
BE ADVECTED WESTWARD ALONG THE LARAMIE RANGE WITH TIME AS STRONG SFC
CYCLOGENESIS OVER EASTERN CO KEEPS NEAR-SFC FLOW BACKED OVER OUR CWA
THROUGH THE DAY. FORECAST SOUNDINGS AND THE OPERATIONAL HRRR SHOW AT
LEAST SOME POTENTIAL FOR FOG OVER THE PLAINS THROUGH 15Z. HOWEVER...
WIDESPREAD SHOWER ACTIVITY SHOULD KEEP THE BOUNDARY LAYER MIXED. WE
DECIDED TO REMOVE MENTION OF FOG FROM THE GRIDS AS ANY REDUCED VSBYS
WOULD BE QUITE ISOLATED.
ATTENTION THEN SHIFTS TO A MORE WIDESPREAD...POTENTIALLY SIGNIFICANT
SEVERE WEATHER EPISODE EVOLVING LATER TODAY. WE WILL REALLY NEED TO
WATCH THE POSITION OF THE SURFACE LOW TODAY AS LLVL WIND FIELDS WILL
PLAY A SIGNIFICANT ROLE IN CONVECTIVE MODE AND STORM INTENSITY. THE
GFS IS STILL AN APPARENT OUTLIER WITH 18-00Z POSITIONING OF A 995 MB
SURFACE LOW LIFTING OUT OF NORTHEAST CO. NOTHING UNUSUAL FOR THE GFS
AS THIS MODEL DOES HAVE A TENDENCY TO PUSH SURFACE FEATURES EASTWARD
TOO QUICKLY. THE NET RESULT IS THE DEVELOPMENT OF WESTERLY FLOW NEAR
THE SURFACE OVER MOST OF THE CWA BY AROUND 21Z. THE PREFERRED SOLNS
ARE STILL THE ECMWF AND NAM WITH THE SLOWER PROGRESSION...AND LONGER
RESIDENCE TIME OF EASTERLY FLOW EAST OF THE LARAMIE RANGE. THE BIG
QUESTIONS RIGHT NOW WILL BE ONGOING CONVECTION/LOW CLOUDS AND THEIR
OVERALL IMPACT ON INSTABILITY PARAMETERS. MORNING WATER VAPOR SHOWS
A MID LEVEL DRY SLOT MOVING INTO EASTERN CO...AND CLOUD TOPS ON THE
LATEST IR LOOP HAVE BEEN WARMING OVER THE LAST FEW HOURS. THUS...DO
NOT EXPECT PCPN TO BE A MAJOR INHIBITING FACTOR. STRONGLY DIFLUENT
FLOW ALOFT IS NOW DEVELOPING ACROSS THE CWA AHEAD OF A VIGOROUS LOW
OVER CA/NV...ALONG WITH A COUPLED H25 JET. MOST CONVECTION-ALLOWING
MODELS SHOW CIN ERODING ENTIRELY BY 18Z...SO STRONGLY BELIEVE THIS
WILL BE AN EARLY SHOW WITH TSTMS BECOMING WIDESPREAD BY AFTN. H7
TEMPS AROUND +7 DEG C OVER THE PANHANDLE WOULD SUGGEST CAPPING AND
LESS COVERAGE THERE. THE AFOREMENTIONED SURFACE BOUNDARY WILL LIFT
NORTHWARD AS A WARM FRONT LATER TODAY...SO THIS WILL SERVE AS THE
PRIMARY FOCUS FOR INITIATION AS WELL AS ENHANCED CONVERGENCE ALONG
THE LARAMIE RANGE.
ENVIRONMENTAL PARAMETERS CONTINUE TO SUGGEST INCREASING POTENTIAL
FOR DANGEROUS THUNDERSTORMS ALONG/EAST OF THE LARAMIE RANGE. GOOD
INSOLATION AND DEW POINTS IN THE MID 50S BENEATH VERY STEEP MID
LEVEL LAPSE RATES SHOULD YIELD SBCAPE OF 2000-3000 J/KG INVOF THE
WARM FRONT. 0 TO 6 KM SHEAR OVER 45 KTS IS EXPECTED TO BE MORE THAN
SUFFICIENT FOR SUPERCELLS INITIALLY...WITH 0-3 KM SRH VALUES WELL IN
EXCESS OF 200 M2/S2. THIS IS ESPECIALLY TRUE WHEN SHEAR VECTORS
ARE ORIENTED PERPENDICULAR TO THE FRONT AROUND 18Z. THE
CONVERGENCE ZONE EVENTUALLY BECOMES ORIENTED MORE SW-TO-NE BY
00Z...WHICH COULD HELP TRANSITION THINGS TO A LINEAR STORM MODE.
WOULD STILL EXPECT A FEW EMBEDDED SUPERCELLS IN SUCH AN
ENVIRONMENT. THE LATEST DAY 1 OUTLOOK FROM THE STORM PREDICTION
CENTER MAINTAINS AN ENHANCED RISK ACROSS MUCH OF THE PANHANDLE
INTO FAR EASTERN WYO. HRRR AND OTHER SIMULATED RADAR PRODUCTS SHOW
CONVECTION DEVELOPING OVER THE LARAMIE RANGE BY LATE MORNING OR
EARLY AFTERNOON...AND THEN MOVING EAST BEFORE MOVING OUT AROUND
03Z. UPDRAFT HELICITIES WOULD SUGGEST SUPERCELLS. VERY
LARGE/DAMAGING HAIL AND STRONG DOWNBURST WINDS SHOULD BE THE
PRIMARY HAZARD TODAY...BUT TORNADOES ARE ALWAYS POSSIBLE IN BACKED
LLVL FLOW REGIMES SUCH AS THESE. SOUNDINGS SHOW VERY LARGE/CURVED
HODOGRAPHS WITH 0-1 KM SHEAR OVER 20 KTS. NAM EHI VALUES ARE OVER
3...SO WOULD NOT BE SURPRISED TO SEE A FEW TORNADOES TODAY. OUR
MAIN CORRIDOR OF INTEREST WOULD BE FROM WHEATLAND/CHUGWATER
(ENHANCED CONVERGENCE WITH A MESOSCALE LOW) EASTWARD ACROSS THE
NEB PANHANDLE. VERY LOW LCLS ARE ALSO OMINOUS. ONE THING THAT
WOULD REALLY MESS UP OUR SEVERE POTENTIAL TODAY WOULD BE A LIKELY
MESSY STORM MODE. A LOT OF DIFFERENT FORCING MECHANISMS
TODAY...AND IT COULD BE DETRIMENTAL IF STORMS BECOME TOO
WIDESPREAD. THAT SAID...THE BUST POTENTIAL IS HIGH. THAT IS NOT TO
SAY WE WILL NOT NEED ALL HANDS ON DECK TODAY THOUGH.
A MUDDLED PATTERN WILL CONTINUE THROUGH THE REST OF THE WEEKEND WITH
DEEP TROUGHING OVER THE WESTERN CONUS. DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL EXIST WITH A VIRTUALLY UNLIMITED SUPPLY OF MIDLVL
DISTURBANCES ROUNDING THE BASE OF THE TROUGH. GFS 700 MILLIBAR TEMPS
AT OR BELOW -2 DEG C SUGGESTS POTENTIAL FOR ACCUMULATING SNOW OVER
THE MOUNTAINS...BUT THIS SHOULD BE SUB ADVISORY AT BEST AS DYNAMICS
DO NOT APPEAR TO BE ANYTHING TO WRITE HOME ABOUT. TEMPERATURES WILL
GENERALLY BE BELOW NORMAL WITH WIDESPREAD CLOUDS AND OCCASIONAL
PCPN.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 415 AM MDT FRI MAY 15 2015
RATHER COOL AND UNSETTLED EXTENDED PERIOD CONTINUES TO BE SHOWN BY
THE MODELS. MONDAY WILL LIKELY BE THE DRIEST DAY ACROSS THE REGION
WITH THE RIDGING ALOFT AND VERY LIMITED INSTABILITY (MAINLY OUT
WEST). THE BEST CHANCE OF SHOWERS WILL BE ALONG AND WEST OF THE
LARAMIE RANGE. SOUTHEASTERLY SFC WINDS WILL PUSH HIGHER DEWPOINTS
TOWARD THE LARAMIE RANGE BY TUES MORNING. AN UPPER LEVEL SYSTEM
OVER CALIFORNIA ON MON WITH MOVE QUICKLY NORTHEASTWARD ON TUES.
UPPER LEVEL DIVERGENCE AND DEEP LAYER ASCENT WILL INCREASE BY TUES
AFTN AND EVENING AND INTERACT WITH GOOD MOISTURE (PW VALUES ARE
ABOVE 0.75 INCHES) TO PRODUCE WIDESPREAD RAIN AND MAYBE AN
ISOLATED TSTM. LOOKING MORE LIKE A STRATIFORM EVENT...AND STRONG
STORMS WOULD NOT BE A CONCERN WITH THE GFS SHOWING REALLY NO CAPE
ACROSS THE PLAINS. WEAK SHORTWAVE WILL BE IN THE VICINITY OF
SOUTHWEST SOUTH DAKOTA ON WED WITH SCATTERED SHOWERS PERSISTING.
THERE IS SOME INDICATION THAT IT WILL DRY OUT BY THURS...HOWEVER
CAN NOT RULE OUT ISOLATED CONVECTION WITH LLVL UPSLOPE TO THE EAST
OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 549 AM MDT FRI MAY 15 2015
LOW CLOUDS AND IFR/MVFR CONDITIONS WILL PERSIST THROUGH THE MID
MORNING AT MANY OF THE PLAINS SITES. THE LOW CLOUDS WILL LIFT AND
BECOME MORE SCATTERED AFTER AROUND 16Z. GOOD MOISTURE AND
INSTABILITY WILL PROMOTE WIDESPREAD THUNDERSTORM DEVELOP BY EARLY
THIS AFTERNOON...ESPECIALLY TO THE EAST OF THE LARAMIE RANGE. SOME
OF THE STORMS COULD BE STRONG WITH GUSTY WINDS...HAIL...AND BRIEF
HEAVY RAIN. PREVAILING WINDS OUTSIDE OF THE STORMS WILL GENERALLY
BE FROM THE SOUTH TO SOUTHEAST.
&&
.FIRE WEATHER...
ISSUED AT 351 AM MDT FRI MAY 15 2015
MILD AND WET WEATHER PATTERN WILL CONTINUE OVER THE NEXT SEVERAL
DAYS. WETTING RAINS CAN BE EXPECTED FOR MANY AREAS. AS A RESULT...
FIRE WEATHER CONCERNS WILL BE MINIMAL WITH NON-CRITICAL CONDITIONS
LIKELY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
505 AM MDT FRI MAY 15 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT FRI MAY 15 2015
SHOWERS AND A FEW STRONG THUNDERSTORMS HAVE BEEN ONGOING FOR MUCH OF
THE NIGHT OVER THE PLAINS. THIS IS IN RESPONSE TO STRONG LLVL THETA-
E ADVECTION NORTH OF A STATIONARY BOUNDARY DRAPED FROM WEST TO EAST
ALONG THE I-80 CORRIDOR. BUFKIT SOUNDINGS FROM THE RAP MODEL SHOW UP
TO 500 J/KG OF MUCAPE TO THE NORTH OF THIS BOUNDARY...WHICH COMBINED
WITH MODEST DEEP LAYER VERTICAL SHEAR IS CONTRIBUTING TO SOME SMALL
HAIL PRODUCTION. ISSUED A FEW SPS PRODUCTS THIS MORNING TO HIGHLIGHT
THE STRONGEST CELLS...BUT EVERYTHING IS STAYING SUB-SEVERE. AIR MASS
ACROSS MUCH OF SOUTHEAST WYO/WESTERN NEB IS BECOMING VERY MOIST THIS
MORNING WITH LLVL EASTERLY/UPSLOPE FLOW. DEWPOINTS OVER WESTERN NEB
WERE ALREADY IN THE 50-55 F RANGE AT 10Z...AND THESE ARE EXPECTED TO
BE ADVECTED WESTWARD ALONG THE LARAMIE RANGE WITH TIME AS STRONG SFC
CYCLOGENESIS OVER EASTERN CO KEEPS NEAR-SFC FLOW BACKED OVER OUR CWA
THROUGH THE DAY. FORECAST SOUNDINGS AND THE OPERATIONAL HRRR SHOW AT
LEAST SOME POTENTIAL FOR FOG OVER THE PLAINS THROUGH 15Z. HOWEVER...
WIDESPREAD SHOWER ACTIVITY SHOULD KEEP THE BOUNDARY LAYER MIXED. WE
DECIDED TO REMOVE MENTION OF FOG FROM THE GRIDS AS ANY REDUCED VSBYS
WOULD BE QUITE ISOLATED.
ATTENTION THEN SHIFTS TO A MORE WIDESPREAD...POTENTIALLY SIGNIFICANT
SEVERE WEATHER EPISODE EVOLVING LATER TODAY. WE WILL REALLY NEED TO
WATCH THE POSITION OF THE SURFACE LOW TODAY AS LLVL WIND FIELDS WILL
PLAY A SIGNIFICANT ROLE IN CONVECTIVE MODE AND STORM INTENSITY. THE
GFS IS STILL AN APPARENT OUTLIER WITH 18-00Z POSITIONING OF A 995 MB
SURFACE LOW LIFTING OUT OF NORTHEAST CO. NOTHING UNUSUAL FOR THE GFS
AS THIS MODEL DOES HAVE A TENDENCY TO PUSH SURFACE FEATURES EASTWARD
TOO QUICKLY. THE NET RESULT IS THE DEVELOPMENT OF WESTERLY FLOW NEAR
THE SURFACE OVER MOST OF THE CWA BY AROUND 21Z. THE PREFERRED SOLNS
ARE STILL THE ECMWF AND NAM WITH THE SLOWER PROGRESSION...AND LONGER
RESIDENCE TIME OF EASTERLY FLOW EAST OF THE LARAMIE RANGE. THE BIG
QUESTIONS RIGHT NOW WILL BE ONGOING CONVECTION/LOW CLOUDS AND THEIR
OVERALL IMPACT ON INSTABILITY PARAMETERS. MORNING WATER VAPOR SHOWS
A MID LEVEL DRY SLOT MOVING INTO EASTERN CO...AND CLOUD TOPS ON THE
LATEST IR LOOP HAVE BEEN WARMING OVER THE LAST FEW HOURS. THUS...DO
NOT EXPECT PCPN TO BE A MAJOR INHIBITING FACTOR. STRONGLY DIFLUENT
FLOW ALOFT IS NOW DEVELOPING ACROSS THE CWA AHEAD OF A VIGOROUS LOW
OVER CA/NV...ALONG WITH A COUPLED H25 JET. MOST CONVECTION-ALLOWING
MODELS SHOW CIN ERODING ENTIRELY BY 18Z...SO STRONGLY BELIEVE THIS
WILL BE AN EARLY SHOW WITH TSTMS BECOMING WIDESPREAD BY AFTN. H7
TEMPS AROUND +7 DEG C OVER THE PANHANDLE WOULD SUGGEST CAPPING AND
LESS COVERAGE THERE. THE AFOREMENTIONED SURFACE BOUNDARY WILL LIFT
NORTHWARD AS A WARM FRONT LATER TODAY...SO THIS WILL SERVE AS THE
PRIMARY FOCUS FOR INITIATION AS WELL AS ENHANCED CONVERGENCE ALONG
THE LARAMIE RANGE.
ENVIRONMENTAL PARAMETERS CONTINUE TO SUGGEST INCREASING POTENTIAL
FOR DANGEROUS THUNDERSTORMS ALONG/EAST OF THE LARAMIE RANGE. GOOD
INSOLATION AND DEW POINTS IN THE MID 50S BENEATH VERY STEEP MID
LEVEL LAPSE RATES SHOULD YIELD SBCAPE OF 2000-3000 J/KG INVOF THE
WARM FRONT. 0 TO 6 KM SHEAR OVER 45 KTS IS EXPECTED TO BE MORE THAN
SUFFICIENT FOR SUPERCELLS INITIALLY...WITH 0-3 KM SRH VALUES WELL IN
EXCESS OF 200 M2/S2. THIS IS ESPECIALLY TRUE WHEN SHEAR VECTORS
ARE ORIENTED PERPENDICULAR TO THE FRONT AROUND 18Z. THE
CONVERGENCE ZONE EVENTUALLY BECOMES ORIENTED MORE SW-TO-NE BY
00Z...WHICH COULD HELP TRANSITION THINGS TO A LINEAR STORM MODE.
WOULD STILL EXPECT A FEW EMBEDDED SUPERCELLS IN SUCH AN
ENVIRONMENT. THE LATEST DAY 1 OUTLOOK FROM THE STORM PREDICTION
CENTER MAINTAINS AN ENHANCED RISK ACROSS MUCH OF THE PANHANDLE
INTO FAR EASTERN WYO. HRRR AND OTHER SIMULATED RADAR PRODUCTS SHOW
CONVECTION DEVELOPING OVER THE LARAMIE RANGE BY LATE MORNING OR
EARLY AFTERNOON...AND THEN MOVING EAST BEFORE MOVING OUT AROUND
03Z. UPDRAFT HELICITIES WOULD SUGGEST SUPERCELLS. VERY
LARGE/DAMAGING HAIL AND STRONG DOWNBURST WINDS SHOULD BE THE
PRIMARY HAZARD TODAY...BUT TORNADOES ARE ALWAYS POSSIBLE IN BACKED
LLVL FLOW REGIMES SUCH AS THESE. SOUNDINGS SHOW VERY LARGE/CURVED
HODOGRAPHS WITH 0-1 KM SHEAR OVER 20 KTS. NAM EHI VALUES ARE OVER
3...SO WOULD NOT BE SURPRISED TO SEE A FEW TORNADOES TODAY. OUR
MAIN CORRIDOR OF INTEREST WOULD BE FROM WHEATLAND/CHUGWATER
(ENHANCED CONVERGENCE WITH A MESOSCALE LOW) EASTWARD ACROSS THE
NEB PANHANDLE. VERY LOW LCLS ARE ALSO OMINOUS. ONE THING THAT
WOULD REALLY MESS UP OUR SEVERE POTENTIAL TODAY WOULD BE A LIKELY
MESSY STORM MODE. A LOT OF DIFFERENT FORCING MECHANISMS
TODAY...AND IT COULD BE DETRIMENTAL IF STORMS BECOME TOO
WIDESPREAD. THAT SAID...THE BUST POTENTIAL IS HIGH. THAT IS NOT TO
SAY WE WILL NOT NEED ALL HANDS ON DECK TODAY THOUGH.
A MUDDLED PATTERN WILL CONTINUE THROUGH THE REST OF THE WEEKEND WITH
DEEP TROUGHING OVER THE WESTERN CONUS. DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL EXIST WITH A VIRTUALLY UNLIMITED SUPPLY OF MIDLVL
DISTURBANCES ROUNDING THE BASE OF THE TROUGH. GFS 700 MILLIBAR TEMPS
AT OR BELOW -2 DEG C SUGGESTS POTENTIAL FOR ACCUMULATING SNOW OVER
THE MOUNTAINS...BUT THIS SHOULD BE SUB ADVISORY AT BEST AS DYNAMICS
DO NOT APPEAR TO BE ANYTHING TO WRITE HOME ABOUT. TEMPERATURES WILL
GENERALLY BE BELOW NORMAL WITH WIDESPREAD CLOUDS AND OCCASIONAL
PCPN.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 415 AM MDT FRI MAY 15 2015
RATHER COOL AND UNSETTLED EXTENDED PERIOD CONTINUES TO BE SHOWN BY
THE MODELS. MONDAY WILL LIKELY BE THE DRIEST DAY ACROSS THE REGION
WITH THE RIDGING ALOFT AND VERY LIMITED INSTABILITY (MAINLY OUT
WEST). THE BEST CHANCE OF SHOWERS WILL BE ALONG AND WEST OF THE
LARAMIE RANGE. SOUTHEASTERLY SFC WINDS WILL PUSH HIGHER DEWPOINTS
TOWARD THE LARAMIE RANGE BY TUES MORNING. AN UPPER LEVEL SYSTEM
OVER CALIFORNIA ON MON WITH MOVE QUICKLY NORTHEASTWARD ON TUES.
UPPER LEVEL DIVERGENCE AND DEEP LAYER ASCENT WILL INCREASE BY TUES
AFTN AND EVENING AND INTERACT WITH GOOD MOISTURE (PW VALUES ARE
ABOVE 0.75 INCHES) TO PRODUCE WIDESPREAD RAIN AND MAYBE AN
ISOLATED TSTM. LOOKING MORE LIKE A STRATIFORM EVENT...AND STRONG
STORMS WOULD NOT BE A CONCERN WITH THE GFS SHOWING REALLY NO CAPE
ACROSS THE PLAINS. WEAK SHORTWAVE WILL BE IN THE VICINITY OF
SOUTHWEST SOUTH DAKOTA ON WED WITH SCATTERED SHOWERS PERSISTING.
THERE IS SOME INDICATION THAT IT WILL DRY OUT BY THURS...HOWEVER
CAN NOT RULE OUT ISOLATED CONVECTION WITH LLVL UPSLOPE TO THE EAST
OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1146 PM MDT THU MAY 14 2015
WYOMING TAFS...SCATTERED SHOWERS DEVELOPING LATER TONIGHT. VFR
PREVAILS WITH PERIODS OF MVFR IN SHOWERS. IFR DEVELOPING THROUGH
THE PREDAWN HOURS AT LARAMIE AND CHEYENNE WITH LOW CLOUDS AND FOG
CONTINUING INTO MID MORNING. ISOLATED TO SCATTERED THUNDERSTORMS
DEVELOPING BY LATE MORNING FRIDAY AND CONTINUING IN THE AFTERNOON
WITH STORMS PRODUCING WIND GUSTS TO 35 KNOTS AND HAIL UP TO ONE
INCH IN DIAMETER. THUNDERSTORMS ENDING BY EARLY FRIDAY EVENING.
NEBRASKA TAFS...WIDESPREAD IFR DEVELOPING LATE THIS EVENING AND
OVERNIGHT WITH WIDESPREAD LOW CLOUDS AND FOG...ALONG WITH
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. AFTER DAYBREAK ON
FRIDAY...BECOMING MVFR IN THE MORNING WITH ISOLATED TO SCATTERED
THUNDERSTORMS DEVELOPING...AND INCREASING IN COVERAGE IN THE
AFTERNOON. ISOLATED TO SCATTERED THUNDERSTORMS WILL BECOME STRONG
TO SEVERE...WITH A FEW STORMS PRODUCING WIND GUSTS IN EXCESS OF 50
KNOTS AND WITH GS AND GR SIZE HAIL...AND A FEW SEVERE STORMS
PRODUCING HAILSTONES IN EXCESS OF ONE INCH IN
DIAMETER...ESPECIALLY NORTH OF A SCOTTSBLUFF TO ALLIANCE LINE.
THUNDERSTORMS ENDING IN THE EARLY EVENING WITH VFR PREVAILING.
&&
.FIRE WEATHER...
ISSUED AT 351 AM MDT FRI MAY 15 2015
MILD AND WET WEATHER PATTERN WILL CONTINUE OVER THE NEXT SEVERAL
DAYS. WETTING RAINS CAN BE EXPECTED FOR MANY AREAS. AS A RESULT...
FIRE WEATHER CONCERNS WILL BE MINIMAL WITH NON-CRITICAL CONDITIONS
LIKELY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...ZF
AVIATION...RUBIN
FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS NEW YORK NY
142 AM EDT SUN MAY 17 2015
.SYNOPSIS...
A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST...LINGERING
NEARBY ON SUNDAY. A BACKDOOR COLD FRONT MOVES THROUGH SUNDAY
NIGHT. THE FRONT STALLS JUST SOUTHWEST OF THE REGION ON MONDAY
WITH HIGH PRESSURE BUILDING IN FROM THE NORTHEAST. THIS FRONT WILL
LIFT THROUGH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD
FRONT ON TUESDAY. HIGH PRESSURE IS THEN IN CONTROL INTO NEXT
WEEKEND...WITH THE EXCEPTION OF A WEAK COLD FRONTAL PASSAGE ON
FRIDAY
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATED TEMPS/DEW POINTS. ADDED PATCHY FOG PER LATEST NARRE PROB
FOR VSBY LESS THAN 1 MILE. THIS MAKES SENSE DUE TO LINGERING LOW
LEVEL MOISTURE AND LIGHT WINDS...WITH GOOD COVERAGE FOR
SHOWERS/TSTMS.
MOST MESOSCALE MODELS...INCLUDING HRRR WHICH HAS BEEN GOOD FROM
RUN TO RUN...INDICATES CONVECTION CONTINUING THROUGH MIDNIGHT...
THEN DIMINISHING IN COVERAGE LATER TONIGHT. UPDATES THIS EVENING
BASED ON THESE TRENDS...AND ANALYSIS.
HIGH PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY
DOWNPOURS IN ANY STORM. MINOR URBAN FLOODING REMAINS A
POSSIBILITY...BUT SHOULD BE LESS LIKELY AS THE NIGHT PROGRESSES.
TEMPERATURES TONIGHT WILL BE MILD...IN THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
DEEP UPPER LEVEL RIDGE BUILDS ACROSS THE EASTERN US ON SUNDAY.
SURFACE TROUGH LINGERS ACROSS THE AREA. WITH A DRIER AIR MASS IN
PLACE...EXPECTING MORE IN THE WAY OF SUNSHINE. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE LOWER AND MIDDLE 80S INLAND AND IN
THE NYC METRO...AND THE UPPER 70S CLOSER TO THE COAST. INSTABILITY
WILL BE ON THE INCREASE DURING THE DAY FROM THE CITY NORTH AND
WEST. AFTERNOON SEA BREEZES FURTHER EAST WILL LIMIT INSTABILITY.
LOW CHANCE POPS FORECAST ACROSS WESTERN ZONES IN THE BETTER
INSTABILITY AND WITH SURFACE TROUGH IN THE VICINITY. HOWEVER...THE
UPPER LEVEL RIDGE SHOULD LIMIT CONVECTIVE DEVELOPMENT. IF A STORM
DEVELOPS SUNDAY...IT MAY BE SLOW MOVING WITH WEAK LOW AND MIDDLE
LEVEL FLOW.
HIGH PRESSURE WILL BEGIN TO BUILD SW ACROSS THE AREA SUNDAY NIGHT
SENDING A BACK DOOR FRONT THROUGH. MODELS DIFFER IN THE TIMING OF
THE FRONT PASSAGE. CURRENT THINKING IS THAT THE FRONT WILL BEGIN
MOVING SOUTH ACROSS THE AREA SUNDAY EVENING. WITH THIS FRONT...AN
ISOLATED SHOWER OR STORM CANNOT BE RULED OUT. AS THE LOW LEVELS
COOL AND MOISTEN BEHIND THE FRONT...SOME FOG OR DRIZZLE ARE
POSSIBLE BY DAYBREAK MONDAY. LOW TEMPERATURES IN THE UPPER 50S AND
LOWER 60S ARE FORECAST SUNDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. SLIGHT DIFFERENCES COME INTO PLAY WITH TIMING AND
AMPLITUDE OF A SHORTWAVE TROUGH MOVING THROUGH NEW ENGLAND ON
WED...ALTHOUGH SHOWER/TSTM ACTIVITY CURRENTLY LOOKS TO REMAIN TO OUR
N. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE WEEK WITH
ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING AROUND THE
BASE RESULTS IN AMPLIFICATION.
AT THE SFC...A FRONTAL BOUNDARY JUST TO THE SW OF THE AREA MON
MORNING...WILL REMAIN NEARLY STATIONARY AS SUBSIDENCE FROM HIGH PRES
TO THE NE NOSES IN. LOW LEVELS SATURATE EARLY IN THE MORNING AS A
RESULT WITH STRATUS EXPECTED AND WITH WEAK LIFT IN THE SATURATED
LAYER COULD CAUSE DRIZZLE. THERE IS ALSO A WEAK SHORTWAVE MOVING
THROUGH THE FLOW ALOFT WHICH COULD CAUSE A FEW AREAS OF RAIN. THE
LATTER WILL BE DETERMINED BY HOW MUCH DRY AIR IS IN PLACE ALOFT FROM
THE HIGH. HAVE ADDED SLIGHT CHANCE RAIN OR DRIZZLE FOR A FEW HOURS MON
MORNING AS A RESULT. WITH THE FRONT NEARBY THROUGH THE DAY...HAVE
MAINTAINED THE SLIGHT CHANCE POPS MAINLY FROM NYC AND AREAS N AND W FOR ANY
ACTIVITY THAT MAY DEVELOP IN THE AFTERNOON WITH WEAK AREAS OF VORTICITY
MOVING THROUGH THE MID-LEVELS. MON NIGHT MAY END UP BEING DRY FOR
THE MOST PART WITH MODEL TRENDS INDICATING THAT ANY ACTIVITY REMAINS
TO OUR SW...BUT MAINTAINED THE SLIGHT CHANCE TO LOW CHANCE POPS FOR THE TIME
BEING SINCE THERE IS UNCERTAINTY WITH HOW MUCH THE HIGH TO THE NE
BUILDS IN.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN THE
EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH PRESSURE
THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH THE END OF
THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER ASSOCIATED WITH A
WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
A SURFACE TROUGH CROSSES THE AREA EARLY THIS MORNING. A BACKDOOR
COLD FRONT APPROACHES FROM THE NORTH AND SINKS TO THE SOUTH LATER
TODAY AND MOVES THROUGH THE REGION MONDAY MORNING.
CONVECTION PRETTY MUCH DONE...AND RAIN WILL TAPER OFF BY 08-09Z.
FOG/STRATUS WILL DEVELOP THEREAFTER...MAINLY WITH MVFR CONDS...BUT
CANNOT RULE OUT IFR/LIFR CONDS.
VFR RETURNS BY 15Z.
LGT/VRB WINDS THROUGH LATE MORNING...THEN GENERALLY SW WINDS 5-10
KT...BECOMING SOUTH AT COASTAL TERMINALS DUE TO AFTERNOON SEA
BREEZES.
WINDS DIMINISH TO 5 KT OR LESS AFT 02Z MONDAY.
FOG/STRATUS LIKELY AGAIN THEREAFTER.
.OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY...
.SUNDAY NIGHT-MONDAY EVENING...MVFR OR LOWER POSSIBLE IN
LOW CLOUDS/FOG. NE WINDS G15-20KT POSSIBLE DURING THE DAY ON
MONDAY.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
S WINDS 10-20 KT DIMINISH OVERNIGHT. BRIEF GUSTY WINDS ARE ALSO
POSSIBLE IN ANY SHOWER AND THUNDERSTORMS THAT MAY MOVE ACROSS THE
WATERS. FOG DEVELOPS.
OTHERWISE...SUB-SCA CONDITIONS ARE FORECAST FOR THE REMAINDER OF
THE FORECAST PERIOD WITH A RELATIVELY LIGHT FLOW PERSISTING ACROSS
THE AREA. GUSTS MAY REACH AROUND 20 KT LATE TUE NIGHT THROUGH
WED.
&&
.HYDROLOGY...
BASIN AVERAGE RAINFALL OF 1/4 INCH IS POSSIBLE THROUGH SUNDAY
MORNING WITH LOCALIZED HIGHER AMOUNTS IN A BAND OF SHOWERS AND
THUNDERSTORMS. MINOR URBAN FLOODING IS POSSIBLE IN ANY OF THE
HEAVIER SHOWERS/STORMS.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...24/DS
NEAR TERM...DS/PW
SHORT TERM...DS
LONG TERM...24
AVIATION...MPS
MARINE...24/DS/PW
HYDROLOGY...24/DS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
428 AM EDT SUN MAY 17 2015
.SYNOPSIS...
A WEAK FRONT WILL REMAIN ACROSS THE REGION TODAY AND TONIGHT. WEAK
HIGH PRESSURE WILL BE ACROSS THE AREA MONDAY. A LOW PRESSURE SYSTEM
WILL MOVE ACROSS THE UPPER GREAT LAKES AND SOUTHERN CANADA BRINGING
ITS ATTACHED FRONTS TO OUR AREA MONDAY NIGHT THROUGH TUESDAY NIGHT.
HIGH PRESSURE WILL BUILD IN FOR THE MIDDLE PART OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MAINLY CLOUDY CONDITIONS, ISOLATED SHOWERS, AND EVEN SOME PATCHY FOG
ARE EXPECTED AT THE START OF THE DAY, WITH AMPLE LOW LEVEL MOISTURE
REMAINING ACROSS THE REGION. WHILE ANY PATCHY FOG SHOULD DISSIPATE
EARLY ON, THE CLOUDS ARE EXPECTED TO REMAIN THROUGH THE DAY, WITH
ONLY A FEW BREAKS POSSIBLE. AN UPPER LEVEL RIDGE WILL BE IN PLACE
OVER THE REGION THROUGH THE DAY, WITH A WEAK FRONTAL BOUNDARY DRAPED
TO OUR NORTH INTO NEW YORK STATE. THE AMPLE MOISTURE IN PLACE AND
THIS WEAK BOUNDARY PERHAPS EDGING SOUTHWARD THROUGH THE DAY WILL
YIELD SOME ISOLATED TO SCATTERED SHOWERS ACROSS OUR REGION, AND
PERHAPS SOME THUNDER INTO THE AFTERNOON AND EVENING, DEPENDING ON
DEVELOPING INSTABILITY THROUGH THE DAYTIME. WE FOLLOWED HRRR AND RAP
GUIDANCE TO INCREASE POPS TO LIKELY THIS AFTERNOON AND EVENING,
HIGHEST FOR OUR WESTERN ZONES.
TEMPERATURE-WISE, ANOTHER WARM AND ABOVE-AVERAGE MAY DAY IS IN
STORE, WITH NOTICEABLE HUMIDITY. WE MAINLY TOOK A MET/MAV BLEND WITH
CONTINUITY FOR MAXIMUM TEMPERATURES, AND WE ANTICIPATE HIGHS TO
MAINLY BE IN THE LOWER 80S, EXCEPT SOME 70S ALONG THE COAST AND INTO
THE POCONOS.
&&
.SHORT TERM / MONDAY THROUGH 6 AM MONDAY/...
INTO THIS EVENING AND TONIGHT, ANY SCATTERED TSTORM AND SHOWER
ACTIVITY SHOULD WANE WITH DIMINISHING INSTABILITY AS THE WEAK
BACKDOOR FRONT CONTINUES TO EDGE FARTHER SOUTH THROUGH OUR AREA. WE
DECREASE POPS BACK TO SLIGHT CHANCE/LOW CHANCE FOR LINGERING SHOWERS
FROM EAST TO WEST ACROSS THE FORECAST AREA AS THE NIGHT PROGRESSES.
WITH THE PASSAGE OF THE WEAK FRONTAL BOUNDARY THROUGH MOST OF THE
FORECAST AREA AND A WEAK AREA OF HIGH PRESSURE BUILDING DOWN FROM
THE NORTHEAST STATES, MORE OF A NORTHEASTERLY, ONSHORE FLOW IS
EXPECTED TO DEVELOP OVERNIGHT AND INTO THE EARLY MORNING LEADING UP
TO DAYBREAK MONDAY. THIS WILL ALLOW SOME LOW CLOUDS TO DEVELOP
ACROSS THE REGION, WITH PERHAPS SOME PATCHY/AREAS OF FOG.
TEMPERATURES WILL ONCE AGAIN REMAIN MILD THROUGH THE OVERNIGHT, WITH
LOWS MAINLY IN THE 60S ACROSS THE REGION.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MON THRU TUE NIGHT...A CONTINUATION OF THE UNSETTLED PERIOD. WARM
AND HUMID CONDITIONS AND A COLD FRONT TO CROSS THE AREA TUE/TUE
NIGHT. CHC FOR TSTMS MON THEN LIKELY SHOWERS/TSTMS FOR MON NIGHT
INTO TUE. SPC MENTIONS A MARGINAL RISK FOR SVR TSTMS TUE. DECREASING
POPS TUE NIGHT. TEMPS ABOVE NORMAL.
WED THRU SAT...HIGH PRESSURE EXTENDS ACROSS THE AREA. A DRY PERIOD
EXPECTED. TEMPERATURES NEAR NORMAL FOR THE LATER HALF OF MAY.
HIGHS MOSTLY LOW/MID 70S WITH LOWS IN THE 40S NORTH AND 50S SOUTH.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THROUGH EARLY MORNING...SOME SUB-VFR VSBYS AND/OR CIGS ARE EXPECTED
TO DEVELOP ACROSS THE REGION, WITH AMPLE LOW LEVEL MOISTURE IN
PLACE. MOST OF THE TAF SITES ARE EXPECTED TO HAVE VSBYS DECREASE TO
MVFR, MOSTLY IN THE 4 TO 5 SM RANGE, WITH CONTINUED VFR CEILINGS.
FOR OUR WESTERN AND MORE NORTHERN TAF SITES, NAMELY KRDG/KABE/KTTN,
GUIDANCE INDICATES THAT BOTH VSBYS AND CIGS ARE EXPECTED TO DECREASE
TO MVFR CONDITIONS FOR A TIME. WINDS OVERALL WILL AVERAGE OUT OF THE
WEST-SOUTHWEST AT 5 KNOTS OR LESS, WITH SOME SITES GOING LIGHT AND
VARIABLE.
REST OF TODAY...ANY MVFR VSBYS AND/OR CIGS ARE EXPECTED TO IMPROVE
TO VFR CONDITIONS BY ABOUT 13Z ACROSS THE REGION. VFR CEILINGS ARE
ANTICIPATED TO CONTINUE THROUGH THE DAY, WITH SOME SCATTERED
SHWRS/TSTORMS POSSIBLE. THE BEST TIMING FOR THIS ACTIVITY LOOKS TO
BE IN THE AFTERNOON AND EVENING, AND THIS HAS BEEN INCLUDED IN THE
TAFS. THUNDER WAS NOT INCLUDED, THOUGH, AS CONFIDENCE IN THE TIMING
AND COVERAGE OF TSTORMS IS TOO UNCERTAIN AT THIS TIME. WESTERLY
WINDS INCREASING UP TO AROUND 10 KNOTS ARE EXPECTED THROUGH THE
DAYTIME.
TONIGHT...ANY SCATTERED SHWRS/TSTORMS ARE EXPECTED TO DIMINISH TO
MORE ISOLATED ACTIVITY INTO TONIGHT, WITH WESTERLY WINDS FALLING OFF
TO AROUND 5 KNOTS. DURING THE EARLY MORNING HOURS LEADING UP TO
DAYBREAK MONDAY, AN ONSHORE FLOW WILL BEGIN TO DEVELOP ACROSS THE
REGION, WITH NORTHEASTERLY WINDS IN THE 5 TO 8 KNOT RANGE. THE
CONTINUED LOW LEVEL MOISTURE IN PLACE WILL ALLOW CIGS/VSBYS TO FALL
TO MVFR OR LOCALIZED IFR CONDITIONS.
OUTLOOK...
MON THRU TUE NIGHT...MOSTLY VFR EXCEPT IN SCT SHOWERS/TSTMS.
WED THRU THU...MOSTLY VFR.
&&
.MARINE...
SUB-ADVISORY CONDITIONS ARE ANTICIPATED TO CONTINUE FOR THE COASTAL
WATERS AND DELAWARE BAY THROUGH TODAY AND TONIGHT. SOME WIND GUSTS
BETWEEN 15 TO 20 KNOTS ARE POSSIBLE THROUGH THE DAYTIME OVER THE
WATERS, WITH SEAS AVERAGING 3 TO 4 FEET FOR THE COASTAL WATERS AND
AROUND 2 FEET FOR DELAWARE BAY.
OUTLOOK...
MON THRU TUE NIGHT...SUB-SCA CONDITIONS WITH SCT TSTMS.
WED THRU THU...SUB-SCA CONDITIONS. FAIR WEATHER.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...KLINE
SHORT TERM...KLINE
LONG TERM...O`HARA
AVIATION...KLINE/O`HARA
MARINE...KLINE/O`HARA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
335 AM CDT SUN MAY 17 2015
.SHORT TERM...(TODAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
ANOTHER UNSEASONABLY WARM & MUGGY DAY WITH SOUTHERLY WINDS IS ON TAP
FOR CENTRAL AND SOUTHEAST ILLINOIS TODAY. THIS GENERAL SCENARIO HAS
NOT CHANGED MUCH SINCE YESTERDAY. THE PRIMARY CHANGE EXPECTED FOR
TODAY IS THAT STRONGER DEEP-LAYER SHEAR WILL BE PRESENT, WITH AN
ASSOCIATED INCREASE IN ORGANIZED CONVECTION. THIS WILL BE A CHANGE
FROM THE MOSTLY DISORGANIZED SHOWERS/THUNDERSTORMS OF THE PAST
COUPLE OF DAYS. UNFORTUNATELY, THERE IS QUITE A BIT OF DISAGREEMENT
IN THE CONVECTIVE DETAILS TODAY AMONG THE GUIDANCE. DIFFERENCES ARE
NOT SURPRISING WITH THE SYNOPTIC SCALE MODELS, BUT THEY ARE ALSO
PRESENT IN THE HIGHER RESOLUTION OUTPUT AS WELL. UNDOUBTEDLY, THE
ULTIMATE OUTCOME WILL PROBABLY BE MODULATED BY BOUNDARIES FROM
UPSTREAM CONVECTION THAT MAKES IT INTO AREA AND ASSOCIATED CLOUD
COVER OR LACK THEREOF.
THE REMNANTS OF A PLAINS SQUALL LINE WILL BEGIN TO SPREAD INTO THE
WESTERN PORTION OF THE FORECAST AREA WITHIN THE NEXT COUPLE OF
HOURS. HRRR AND RAP GUIDANCE SUGGEST A RAPID WEAKENING OF THE
STORMS, AND THERE HAS BEEN SIGNIFICANT WEAKENING OF LATE IN RECENT
RADAR LOOPS, AS WELL AS WARMING CLOUD TOPS. THE REMNANTS OF THIS
SYSTEM WILL LIKELY BE KEY TO WHERE THINGS FOCUS IN THE FORECAST AREA
TODAY. MODELS HAVE CONSISTENTLY SUGGESTED CAPE VALUES FROM 1500-2500
J/KG IN THE FORECAST AREA DURING PEAK HEATING TODAY, WHILE BULK
SHEAR VALUES SHOULD BE 35-45 KTS WEST AND 25-35 KTS EAST. THESE
PARAMETERS SUGGEST SOME STRONG TO SEVERE STORMS ARE POSSIBLE IN THE
AREA TODAY, BUT THE EXACT LOCATION/TIMING OF DEVELOPMENT WILL NOT BE
A HIGH CONFIDENCE FORECAST UNTIL WE SEE HOW THINGS PLAY OUT WITH THE
REMNANTS MOVING INTO OUR AREA.
&&
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
00Z FORECAST MODELS TAKE 558 DM 500 MB LOW OVER CENTRAL NEBRASKA NE
INTO NORTHERN MN BY 12Z/MON WHILE 992 MB SURFACE LOW PRESSURE OVER
CENTRAL SD WEAKENS AS IT TRACKS NE INTO NORTHERN MN BY DAWN MONDAY.
THIS WILL BRING AN OCCCLUDED FRONT EAST INTO CENTRAL IL NEAR I-55 BY
18Z/MON AND NEARING THE WABASH RIVER BY 00Z/TUE. HIGHEST CHANCES OF
SHOWERS AND THUNDERSTORMS WILL SHIFT INTO EASTERN IL TONIGHT AND
MONDAY. SPC HAS SLIGHT RISK OF SEVERE STORMS OVER ALL BY FAR SE IL
NEAR WABASH RIVER THIS AFTERNOON/EVENING WITH 15% RISK OF LARGE HAIL
AND DAMAGING WIND GUSTS AND 2-5% RISK OF TORNADOES AND HIGHEST RISK
(5%) OVER KNOX...STARK AND MARSHALL COUNTIES. SPC KEEPS MARGINAL
RISK OF SEVERE STORMS MONDAY EAST OF IL OVER CENTRAL AND EASTERN
INDIANA. MILD LOWS TONIGHT IN THE MID TO UPPER 60S WITH SSW BREEZES.
ANOTHER WARM DAY MONDAY WITH HIGHS IN THE UPPER 70S WEST OF THE IL
RIVER AND LOWER 80S EAST OF THE IL RIVER. SW WINDS TURN WEST AND NW
BEHIND COLD FRONT AND DEWPOINTS WILL BE DROPPING BEHIND THE FRONT
DURING THE DAY. THOUGH STAYING HUMID DURING THE DAY MONDAY OVER
SOUTHEAST IL WITH DEWPOINTS IN THE UPPER 60S TO NEAR 70F.
LINGERED JUST SLIGHT CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORM IN
FAR SE IL NEAR WABASH RIVER MONDAY EVENING. OTHERWISE DRY AND COOLER
AS CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST BY TUE WITH A
FAIR AMOUNT OF SUNSHINE OVER CENTRAL/SE IL TUE WITH NW WINDS. LOWS
MON NIGHT RANGE FROM MID 40S OVER IL RIVER VALLEY TO MID 50S BY
LAWRENCEVILLE. HIGHS TUE RANGE FROM LOWER 60S NORTH OF I-74 TO
AROUND 70F BY LAWRENCEVILLE. ANOTHER COOL NIGHT TUE NIGHT WITH LOWS
IN THE MID TO UPPER 40S.
EXTENDED MODELS CONTINUE TO SHOW A DISTURBANCE EJECTING FROM THE
TROF/CUTOFF LOW NEAR CA INTO THE CENTRAL PLAINS WED AND BRINGING
MAINLY LIGHT QPF INTO CENTRAL AND SW IL WED AND SHIFTING IT
SOUTHWARD WED NIGHT AND THU. HAVE INCREASE POPS BY WED AFTERNOON TO
LIKELY FROM JACKSONVILLE SW WHILE LOWER POPS IN NE CWA BY DANVILLE.
MORE CLOUDS WED AND RAIN CHANCES TO KEEP IT COOLER WITH HIGHS IN
UPPER 50S AND LOWER 60S CENTRAL IL AND MID 60S SOUTHEAST OF I-70.
ANOTHER CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST THU
RETURNING DRY WEATHER AND TEMPS MODERATING DUE TO MORE SUNSHINE WITH
HIGHS IN THE UPPER 60S. SEASONABLE HIGHS REACH THE LOW TO MID 70S
FRIDAY. LOOKS LIKE AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS
DURING THE MEMORIAL DAY WEEKEND ESPECIALLY FROM SAT NIGHT ON WITH
DISTURBANCE EJECTING OUT OF SW UPPER LEVEL FLOW AND INCREASING TEMPS
AND HUMIDITY WITH SOUTHERLY FLOW RETURNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1158 PM CDT SAT MAY 16 2015
NOT TOO MUCH OF A SHIFT. MVFR/IFR CIGS MOVING IN AND SPREADING
OVER CENTRAL IL. SOUTHERLY WINDS CONTINUE. SOME VIS REDUCTION
POSSIBLE WITH THE ENHANCED/TRAPPED LLVL MOISTURE. ISSUES FOR
TOMORROWS FORECAST REMAIN WITH MODELS CHALLENGED BY CONVECTION.
WITH TIMING ISSUES...VCTS STARTING ROUGHLY MIDDAY, THEN PULLING
BACK TO VCSH LATER IN THE EVENING AS THE MAJORITY OF THE PRECIP
STARTING TO LOOK RAGGED ON MODEL DEPICTIONS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...07/BAK
LONG TERM...07
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
343 AM CDT SUN MAY 17 2015
.SYNOPSIS...
ISSUED AT 340 AM CDT SUN MAY 17 2015
SYNOPSIS...HUGE SQUALL LINE OF SEVERE STORMS AND EMBEDDED TORNADOES
EXTENDED ALL THE WAY FROM NORTHERN MO TO CENTRAL TX. HOWEVER...THE
FAR NORTHERN PORTION OF THE LINE APPROACHING NORTHEAST MO AND
SOUTHCENTRAL IA WAS RAPIDLY WEAKENING AS IT RUNS INTO MUCH MORE
STABLE AIR WITH MINIMAL CAPE. ALSO...IR SATELLITE SHOWS RAPIDLY
WARMING TOPS. MEANWHILE BACK AT THE RANCH...LOW STRATUS HAS FORMED
OVER MUCH OF THE CWA DUE TO CONTINUED MOISTURE TRANSPORT FROM THE
SOUTH. 3 AM TEMPERATURES RANGED FROM THE MID 60S TO AROUND 70 WITH
DEWPOINTS IN THE MID 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SUN MAY 17 2015
FORECAST FOCUS ON SEVERE POTENTIAL AND COVERAGE OF THUNDERSTORMS.
TODAY...SPC HAS SHIFTED THE ENHANCED SEVERE RISK NORTH OF THE CWA
CLOSER TO THE STRONGEST SHEAR AND TRIPLE POINT OF THE OCCLUDING
CYCLONE WITH A SLIGHT RISK OVER ALL OF THE CWA. SPC HAS A 5%
PROBABILITY FOR TORNADOES IN NORTHEAST IA AND NORTHERN IL WITH A 15%
PROBABILITY OF WIND AND HAIL OVER THE ENTIRE CWA. THIS IS A LOW
CONFIDENCE FORECAST OF EXACTLY HOW THE CONVECTION WILL PLAY OUT AS
MODELS DIFFER GREATLY...RANGING FROM NUMEROUS TO ONLY ISOLATED
STORMS.
FIRST OF ALL IS THIS MORNING WITH THE RAPIDLY DECAYING SQUALL LINE
WHICH WILL BE MOVING INTO OUR WESTERN AND SOUTHERN CWA EARLY THIS
MORNING...SO WILL HAVE LIKELY POPS FOR THOSE AREAS. THE HRRR MODEL
TAKES THIS WEAK LINE OVER ALL OF EASTERN IA TO ABOUT THE MS RIVER
THEN FADES IT BY MID MORNING...SO WILL HAVE CHANCE POPS THE FARTHER
EAST YOU GO INTO THE CWA. THEN WE HAVE THE LOW STRATUS FOR MUCH OF
THE MORNING WITH THE AVIATION GFS-LAMP GUIDANCE INDICATING THIS TO
DISSIPATE BY LATE MORNING/EARLY AFTERNOON SIMILAR TO YESTERDAY.
THIS AFTERNOON...COVERAGE OF THUNDERSTORMS IS PROBLEMATIC AS MODELS
HAVE DIFFERING SOLUTIONS. MODELS STILL INDICATE STRONG DEEP LAYER
SHEAR WITH 0-6KM OF 40-45 KTS AIDED BY CYCLONICALLY CURVED JET FROM
MID MISSISSIPPI VALLEY INTO GREAT LAKES. TEMPERATURES IN THE LOWER
TO MID 80S AND DEWPTS IN THE MID TO UPPER 60S SHOULD YIELD MODERATE
INSTABILITY WITH MLCAPES OF 1000-2000 J/KG. THIS IS CERTAINLY
SUFFICIENT TO SUPPORT ALL MODES OF SEVERE WEATHER. HOWEVER...WITH
THE OCCLUDING CYCLONE WE ARE ALSO LOSING THE FORCING/LOW LEVEL
CONVERGENCE TO GET STORMS TO DEVELOP...EXCEPT IN OUR FAR EASTERN
COUNTIES EARLY THIS AFTERNOON. THIS WILL BE INTERESTING TO SEE HOW
THIS PLAYS OUT BUT FOR NOW WILL HAVE THE HIGHEST POPS IN THE EAST
AND ONLY SLIGHT POPS IN THE SW. MAXIMUM TEMPERATURES SHOULD GET INTO
THE LOWER TO MID 80S AT MOST LOCATIONS.
TONIGHT...I WILL MAINTAIN THE SMALL POPS FOR EARLY THIS EVENING
ALONG AND EAST OF THE MS RIVER BUT WE COULD JUST AS EASILY BE DRY.
OPERATIONAL MODELS INDICATE DRY SLOT TO SPREAD OVER ALL THE CWA AS
THE OCCLUDING CYCLONE TRACKS INTO THE MN ARROWHEAD. SKIES WILL BE
CLEARING OR CLEAR WITH COOLER AND DRIER AIR BEGINNING TO PUSH INTO
THE NW CWA OVERNIGHT. MINIMUM TEMPERATURES WILL RANGE FROM THE MID
50S NW TO THE LOWER TO MID 60S SE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN MAY 17 2015
COOL BUT NICE MID MAY WEATHER FOR THE UPCOMING WORK WEEK WITH SOME
LIGHT RAIN POSSIBLE WEDNESDAY.
LONG TERM FORECAST CONFIDENCE ASSESSMENT...GOOD OR ABOVE AVERAGE WITH
LITTLE SENSIBLE WEATHER ISSUES. MAIN ISSUE IS DIURNAL TEMPERATURE RANGES
WITH MOST DAYS SUGGESTION OF WIDER RANGES OF HI/LO BY A DEGREE OR SO
MOST LOCATIONS SUPPORTED.
OVERVIEW...INITIALIZATION AND VERIFICATION IS GOOD WITH SLIGHTLY TOO
MOIST BL ISSUES NOTED THAT ARE IMPACTING NORMAL MODEL FIELDS CURRENTLY
AS TOO WIDESPREAD EXCEPT FOR LINEAR FEATURES UNDERDONE. THIS WILL HAVE
NO IMPACT MONDAY ONWARD. RUN TO RUN VARIANCES SUGGEST LITTLE DIFFERENCES
EXCEPT TEMPERATURES BY A CATEGORY OR SO WITH A MEAN TAKEN FOR LATER
SHIFTS TO REASSESS AS AGAIN PROBABLE A DEGREE OR TWO TO COOL/MILD FOR
HIGHS/LOWS MOST DAYS.
MONDAY...STRONG CAA TO RESULT IN BREEZY WEATHER WITH MANY LOCATIONS
TO HAVE NEARLY STEADY TEMPERATURES WITH 15 TO 25+ MPH WITH SOME GUSTS
TO 30 MPH NORTH HALF OF FORECAST AREA. STRONG GRADIENT WITH LOWER 60S
FAR NW TO UPPER 70S FAR SE SECTIONS. MONDAY NIGHT...WINDS MAY BE UP
ENOUGH TO PRECLUDE FROST RISK WITH UPPER 30S NW TO MID 40S SOUTH SECTIONS.
TUESDAY...BELOW NORMAL TEMPERATURES BY 10 TO 15 DEGREES WITH CONTINUED
CAA WITH LOW LEVEL THERMAL FIELDS SUPPORTIVE OF NEAR 60F FAR NORTH TO
MIDDLE 60S SOUTH SECTIONS DESPITE NEARLY FULL TO FULL SUNSHINE.
TUESDAY NIGHT...LIGHT WINDS MAY ALLOW FOR BL DECOUPLING NORTH 1/2
AND PATCHY FROST RISK FOR LATER SHIFT TO RECONSIDER. LOCAL TECHNIQUES
DO SUGGEST WITH FAIR SKIES AND BL DECOUPLING SOME MID 30S POSSIBLE
ALONG AND NORTH OF HIGHWAY 30 CORRIDOR FAVORED LOW LYING LOCATIONS.
WEDNESDAY...INCREASING CLOUDS WITH RISK OF SPRINKLES MOSTLY CENTRAL
SECTIONS AND SOME LIGHT RAIN SOUTH 1/3 OF AREA. HIGHS SHOULD WITH CLOUDS
BE MOSTLY LOWER 60S WITH UPPER 50S POSSIBLE IN HEAVIEST CLOUDS AND
POSSIBLE LIGHT RAIN. WEDNESDAY NIGHT...ANY LIGHT PRECIPITATION SHOULD
END AROUND MIDNIGHT WITH CLEARING SKIES BY MORNING ALL BUT FAR SE
SECTIONS. MINS LOWER TO MIDDLE 40S ARE REASONABLE.
THURSDAY THROUGH SATURDAY...MORE NICE WEATHER WITH UPPER 60S MOST LOCATIONS
FOR HIGHS ON THURSDAY AND LOWER 70S A GOOD REFERENCE POINT FRIDAY/SATURDAY
WITH LOW DEWPOINTS. MINS 40S RISING INTO THE 50S SATURDAY AND SUNDAY
AM WITH PROBABLE MOST LOCATIONS MINS ARE 2 TO 3 PLUS DEGREES TOO MILD
FOR LATER SHIFTS TO CONSIDER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1153 PM CDT SAT MAY 16 2015
THE DISSIPATING REMNANTS FROM A LINE OF STRONG THUNDERSTORMS
ADVANCING FROM THE PLAINS WILL LIKELY MOVE INTO THE EASTERN IOWA
TERMINALS AS LIGHT RAIN WITH MVFR CONDITIONS DUE TO STRATUS AND
FOG TOWARD MORNING. BEYOND...THE FORECAST REMAINS LOW CONFIDENCE
WITH RESPECT TO THE POTENTIAL FOR STRONG TO SEVERE STORMS AS AN
UPPER LEVEL TROUGH MOVES THROUGH LATER IN THE DAY. FOR NOW...THIS
POTENTIAL IS LIMITED TO HIGHER CONFIDENCE CHANCE FOR SHOWERS IN
THE LATE MORNING OR EARLY AFTERNOON. GUSTY SOUTH WINDS WILL
GRADUALLY VEER TO MORE SOUTHWEST TOWARD SUNDAY EVENING WITH
PREVAILING VFR CONDITIONS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...NICHOLS
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1202 AM CDT SUN MAY 17 2015
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 1035 PM CDT SAT MAY 16 2015
WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
TROUGH OF LOW PRESSURE LIFTING NORTHEAST ACROSS THE WESTERN HIGH
PLAINS. MEANWHILE, WEAK UPPER LEVEL RIDGING IS MOVING EASTWARD
ACROSS THE DESERT SOUTHWEST. NEAR THE SURFACE, A BROAD AREA OF LOW
PRESSURE EXTENDS FROM WESTERN NEBRASKA SOUTHWARD INTO EXTREME
EASTERN COLORADO.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 128 PM CDT SAT MAY 16 2015
ABBREVIATED SHORT TERM WITH MET WATCH. MADE ADJUSTMENTS TO POPS
CONCERNING THE NON SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL
KANSAS EARLY THIS AFTERNOON. SOME OF THE ACTIVITY ACROSS OKLAHOMA
HAS BEEN INCREASING IN INTENSITY, SO WILL HAVE TO WATCH OUT FOR
MARGINALLY SEVERE BASICALLY SE OF A LINE FROM ASHLAND TO ST JOHN.
THE NEXT AREA OF CONCERN IS OUT WEST. BUBBLING CUMULUS HAS BEEN
NOTED ON VIS SAT. TOOK A BLEND OF THE HRRR AND WRF-ARW FOR POP
ARRANGEMENTS WITH THIS ACTIVITY. WE LAUNCHED AN 18Z RAOB, WHICH
LOOKS FAR FROM SPECTACULAR. FIRST, INSTABILITY IS OBVIOUSLY VERY
LIMITED WITH ALL LINGERING CLOUD COVER. SECOND, 850-HPA WINDS ARE
VERY WEAK. IN FACT, THE ENTIRE LOW LEVELS ARE WEAK, ALTHOUGH
THERE IS DECENT VEERING. THIRDLY, UPPER LEVEL WINDS ARE BACKED.
TRANSLATION: MESSY HP SUPERCELLS. SO THE SITUATION HAS CHANGED A
BIT FROM PREVIOUSLY THOUGHT. THE MORNING SHOWERS AND THUNDERSTORMS
WILL PROBABLY HAVE DELETERIOUS IMPACTS TO STORM INTENSITY. RAP
ANALYSIS DOES SHOW CAPE INCREASING OUT WEST. STILL THINK WE WILL
STILL SEE SEVERE. THINK TORNADO POTENTIAL IS NOT AS HIGH AS
PREVIOUSLY THOUGH. THERE IS ENOUGH SHEAR TO GET ROTATING STORMS
THOUGH AND A FEW TORNADOES ARE NOT OUT OF THE QUESTION. WHAT IS
IN QUESTION IS IF THE TORNADOES WILL BE STRONG OR NOT. HAVE SEEN
AN UPTICK ON UPDRAFT HELICITY RECENTLY, SO SOMETHING TO MONITOR.
FROM THE 18Z RAOB, IT WILL TAKE QUITE THE ATMOSPHERIC TURN OVER
TO GET IT PRIMED FOR STRONG TORNADOES WITH DECENT INSTABILITY AND
STRENGTHENING LOW LEVEL WINDS. THERE IS SOME CONCERN ACROSS SOUTH-
CENTRAL KANSAS THAT LOW LEVEL WINDS THIS EVENING WILL STRENGTHEN
AND THE TORNADO POTENTIAL COULD GO UP. BUT BY THAT TIME, THE
STORMS COULD BE OUTFLOWY, PRECIPITATION LADEN MESSY STORMS. WILL
CONTINUE TO MONITOR THE MESOSCALE SITUATION AND ADJUST AS
NECESSARY. STORMS WILL BE MOVING AT A GOOD CLIP TOO.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 156 PM CDT SAT MAY 16 2015
THE SOUTHERN BRANCH OF THE WESTERLIES WILL CONTINUE TO BE ACTIVE
WITH AMPLIFICATION RESULTING FROM TROPICAL CONVECTION ACROSS THE
WESTERN PACIFIC. SUNDAY AND MONDAY WILL BE BETWEEN SYSTEMS AND THE
ONLY FORECAST CHALLENGE WILL BE TEMPERATURES AS ACTIVELY GROWING
VEGETATION AND WET SOILS WILL IMPACT TEMPERATURES.
THE NORTHERN BRANCH OF THE WESTERLIES WILL ALLOW SFC HIGH
PRESSURE TO BUILD INTO THE AREA MONDAY. WITH THE APPROACH OF
ANOTHER S/WV TROUGH IN THE SOUTHERN BRANCH, THE MOIST BOUNDARY
LAYER AIR SHOULD BE MOVING BACK NORTHWEST INTO THE HIGHER TERRAIN.
WIDESPREAD CONVECTION SHOULD RESULT BY TUESDAY AND INTO WEDNESDAY.
YET ANOTHER SYSTEM IS EXPECTED TOWARDS NEXT WEEKEND WITH
ADDITIONAL PCPN EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1200 AM CDT SUN MAY 17 2015
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH LATE SUNDAY
AFTERNOON. LIGHT SOUTHERLY WINDS OVERNIGHT WILL BECOME MORE
SOUTHWEST TO WESTERLY EARLY SUNDAY MORNING AS A SURFACE LOW IN
EASTERN COLORADO LIFTS NORTHEAST INTO NEBRASKA.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 50 70 47 63 / 0 10 20 60
GCK 48 69 46 62 / 0 0 20 60
EHA 48 69 48 62 / 0 0 40 70
LBL 51 73 49 64 / 0 0 30 70
HYS 49 67 44 62 / 0 0 10 40
P28 55 76 50 67 / 0 10 10 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...SUGDEN
LONG TERM...HUTTON
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1201 AM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1201 AM CDT SUN MAY 17 2015
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 208 PM CDT SAT MAY 16 2015
LOCALLY HEAVY RAIN IN PARTS OF WEST KY WITH AMOUNTS SINCE MIDNIGHT
1-2" IN A FEW SPOTS...MOSTLY AT OR BELOW 1". AREAL FLOOD
ADVISORIES WILL SUFFICE GIVEN THE PROGRESSIVE NATURE OF THE
ACTIVITY AND THE DOWNWARD TREND EXPECTED OVERALL. LITTLE TO NO
LIGHTNING...DEFINITELY EFFICIENT NONE THE LESS GIVEN WEAK LAPSE
RATES AND SMALL CAPE. ALL THE MODELS POINT TO A DIMINISHING TREND
FOR THE OVERNIGHT IN THE WAKE OF THIS WAVE THAT WE HAVE MONITORED
ON WVAPOR MOVING SLOWLY NE. THE RAP AND NAM WERE GENERALLY
FOLLOWED. WE CONTINUE TO HOLD TEMPS DOWN THE REST OF TODAY AS
WELL. THEY SHOULD FALL LITTLE TONIGHT WITH THE STAGNANT/HUMID
AIRMASS IN PLACE AND SOUTHERLY FLOW THE RULE.
SPC EXPANDED THEIR SLIGHT RISK AREA EAST DAY 2 INTO 1/2 OF THE
AREA FROM THE WEST. THIS SEEMS OVERDONE AND TEND TO DISAGREE. SURE
THERE COULD BE A FEW WARNINGS. BUT ENOUGH QUESTION MARKS EXIST.
THE NAM SUGGESTS A MIN CORRIDOR OF WEAK INSTABILITY ACROSS MUCH
OF THE AREA SUNDAY WITH CONVECTION AND CLOUDS ALREADY INTO THE
AREA AND BETTER DESTABILIZATION TO OUR WEST AND EAST. THE GFS AND
ECMWF SHOW BETTER DESTABILIZATION THROUGH THE DAY. EVEN IF WE
DESTABILIZE... BETTER WIND FIELDS ARE POSITIONED TO OUR WEST AND
NORTH AND NOT SUPPORTIVE OF SUSTAINED ORGANIZATION. WILL KEEP
POPS HIGH CHANCE GIVEN UNCERTAINTY WITH RESPECT TO COVERAGE.
SHOULD BE WARMER THAN TODAY.
SUNDAY NIGHT THROUGH MONDAY EVENING...WILL CONTINUE WITH HIGH
CHANCE TO LOW END LIKELY POPS FOR CONVECTION...AS THE FRONT VERY
SLOWLY WORKS SOUTH INTO THE AREA BY MONDAY EVENING/NIGHT. BEST
CHANCES WILL EVENTUALLY FOCUS ACROSS THE SOUTHEAST 1/2 TO 2/3 OF
THE AREA.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 208 PM CDT SAT MAY 16 2015
HIGHER THAN AVERAGE CONFIDENCE IN THE EXTENDED.
MODELS AND ENSEMBLES IN FAIR AGREEMENT WITH THE EXTENDED FORECAST.
SURFACE HIGH PRESSURE WILL BE THE MAIN SYNOPTIC SCALE FEATURE IN
CONTROL. HOWEVER THERE WILL BE A WEAK PERTURBATION IN THE NEARLY
ZONAL FLOW ALOFT WITH A REFLECTION OF A SURFACE LOW PASSING JUST TO
OUR SOUTH. THIS WILL BRING AT LEAST A CHANCE OF SHOWERS TO THE AREA
WEDNESDAY. SURFACE BASED CONVECTION LOOKS UNLIKELY WITH POSITIVE
LI`S AND LITTLE TO NO CAPE. ALTHOUGH SHOWALTERS IN VERY POSITIVE...K
INDEX VALUES ARE IN THE MID 20S. SO WILL NOT RULE OUT A CLAP OF
THUNDER BUT NOTHING IMPRESSIVE AT THIS TIME. OTHERWISE HIGH PRESSURE
WILL BE THE DOMINANT FEATURE AFTER THE PASSAGE OF THIS SURFACE LOW.
TEMPERATURES WILL BE AT SLIGHTLY BELOW NORMAL IN THE EXTENDED WITH
WINDS RELATIVELY LIGHT AFTER WEDNESDAY.
&&
.AVIATION...
ISSUED AT 1201 AM CDT SUN MAY 17 2015
AREA OF MVFR CEILINGS IS SPREADING EASTWARD TOWARD KCGI AT THIS
TIME...AND FIGURE THAT TREND WILL CONTINUE THROUGH THE OVERNIGHT
HOURS. 50KTS OF SSW WINDS AT 925MB ON THE KPAH 88-D VWP CERTAINLY
IS WORTHY OF A MENTION OF LLWS OVERNIGHT. THINK THERE WILL BE
GUSTS AT KCGI...SO DID NOT INCLUDE IT THERE.
CONVECTION MOVING EAST OUT OF THE PLAINS SHOULD STRUGGLE TO MAKE
IT THIS FAR EAST OVERNIGHT. STILL PLANNING ON A DIURNAL CONVECTIVE
SIGNAL THAT MAY BE ENHANCED BY TAIL END OF PLAINS UPPER SYSTEM AND
POTENTIAL OUTFLOW BOUNDARY FROM TONIGHTS PLAINS CONVECTION. PUSHED
IT BACK AN HOUR OR TWO...ESPECIALLY AT KEVV AND KOWB.
SOUTH SOUTHWEST WINDS WILL INCREASE SIGNIFICANTLY WITH MIXING
LATE MORNING. SOME GUSTS 20-25KT CAN BE EXPECTED.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1210 AM CDT SUN MAY 17 2015
.AVIATION...
TERMINAL FORECAST SITES WILL START OUT WITH PREVAILING VFR...BUT
WITH A STRONG SOUTHERLY FLOW IN THE LOWER LEVELS...MVFR CEILINGS
WILL SPREAD AND DEVELOP OVER THE FOUR STATE REGION SHORTLY AFTER
17/06Z TO 17/09Z. IFR CONDITIONS WILL FOLLOW ACROSS THE REGION
AND WILL BE SLOW TO RETURN TO MVFR DURING THE MID TO LATE MORNING.
VFR MAY BE RETURNING NEAR MID DAY. SHOWERS AND THUNDERWSTORMS
WILL BE MOVING INTO THE EAST AND NORTHEAST TEXAS AND SOUTHWEST
ARKANSAS TERMINALS AFTER 17/09Z TO 17/11Z WITH SHOWERS ACROSS
NORTH LOUISIANA AND SOUTH CENTRAL ARKANSAS. THUNDERST0RMS WILL BE
SPREADING AND DEEVELOPING OVER THE LOUISIANA AND SOUTH CETNRAL
ARKANSAS SITES NEAR LATE AFTERNOON INTO THE EARLY EVENING. WINDS
WILL BE SOUTH 7-13 KNOTS THROUGH 17/14Z THEN INCREASE TO 10-15
KNOTS WITH HIGHER GUSTS ESPECIALLY FOR PARTS OF EAST AND NORTHEAST
TEXAS AND ADJACENT SOUTHWEST ARKANSAS. /06/
PREV DISCUSSION... /ISSUED 933 PM CDT SAT MAY 16 2015/
DISCUSSION...
SEABREEZE CONVECTION DISSIPATED QUICKLY THIS EVENING AND WITH A
CLEAR SCOPE CURRENTLY...HAVE REDUCED POPS THROUGH MIDNIGHT TO
SLIGHT CHANCE VARIETY. THE BIGGER SHOW IS GOING ON TO OUR WEST
WHERE DISCRETE SEVERE THUNDERSTORMS ARE TRYING TO DEVELOP INTO A
BROKEN LINE OF SEVERE CONVECTION...ESPECIALLY ACROSS CENTRAL
OKLAHOMA. LATEST HRRR OUTPUT DOES NOT BRING THIS CONVECTION INTO
OUR EXTREME NW ZONES UNTIL JUST BEFORE 12Z SO HAVE ADJUSTED THE
EXPECTED EASTWARD PROGRESSION OF THIS ACTIVITY WITH THE GRIDS.
LOCAL HEAVY RAINFALL WORDING WAS SHIFTED FURTHER NORTH AND WEST
FROM THE 06-12Z TIMEFRAME AND ADDED THIS MENTION SLIGHTLY FURTHER
EAST DURING THE 12-18Z SUNDAY TIMEFRAME. DID NOT MAKE ANY
ADJUSTMENTS TO THE FFA WHICH WILL GO INTO EFFECT AT 06Z IN THE
MORNING.
OTHER CHANGES INCLUDED SKY GRIDS AND COSMETIC CHANGES TO
WIND/DEWPOINT AND RH GRIDS. OTHERWISE...NO ADDITIONAL CHANGES WERE
NECESSARY THIS EVENING.
UPDATED PACKAGE ALREADY SENT...13.
PREV DISCUSSION... /ISSUED 317 PM CDT SAT MAY 16 2015/
DISCUSSION...
SCATTERED SEA BREEZE TYPE CONVECTION MARCHING NWD THIS AFTN...AND
BEGINNING TO KICK OFF GUSTS FRONTS WITH 30 TO 40 MPH WINDS. DRY
MID LVLS WILL KEEP COVERAGE SCATTERED...UNTIL OVERNIGHT MCS MOVES
DOWN RED RIVER VALLEY. THIS ACTIVITY SHOULD NOT REACH AREA UNTIL
JUST AFTER MIDNIGHT...BUT ADDED NW CORNER OF CWA IN LATE EVE FOR
LIKELY POPS JUST IN CASE...AND LEAVING SOUTHERN SECTIONS AS SLIGHT
CHANCE THIS EVE...WITH AIRMASS MORE WORKED OVER FROM CONVECTION.
FLASH FLOOD WATCH FOR NW SECTIONS OF AREA BEGINNING AT 1 AM. ADDED
LOCALLY HEAVY RAINFALL WITH MCS FOR THOSE SECTIONS...WITH
SATURATED GROUND...JUST A COUPLE INCHES OF RAIN COULD BE A REAL
ISSUE. DEEP SFC LOW MOVG THRU UPPER MIDWEST WILL DRAG ATTENDANT
FRONT ACROSS SOUTHERN PLAINS SUNDAY NIGHT...SWINGING AN EVEN
STRONGER MCS INTO OUR AREA...WHICH SHOULD SPREAD OUT AND BRING
RAIN TO MOST OF THE REGION MONDAY. WILL LIKELY NEED TO REISSUE
FLASH FLOOD WATCH WHICH WILL EXPIRE SUNDAY AT 1 PM...AS PREVIOUS
MCS WILL DIMINISH...AND SHOULD GET A RAIN BREAK FOR AIRMASS TO
RECOVER. SLIGHTLY COOLER AIR IN ZONAL FLOW ALOFT TUESDAY WILL
AFFECT TEMPS SLIGHTLY...AND BRING LOWER RAIN CHANCES TO AREA..BUT
NOT FOR LONG AS FRONT IS EXPECTED TO MEANDER BACK INTO REGION AND
BECOME QUASI STNRY AGAIN BY MID WEEK.
VII
PREV DISCUSSION... /ISSUED 101 PM CDT SAT MAY 16 2015/
AVIATION...
CIGS HAVE BECOME VFR AS OF MIDDAY OVER ALL THE REGION EXCEPT FOR
SCNTRL AR/NE LA...WITH THESE MVFR CIGS OVER THE E EXPECTED TO
BECOME VFR SHORTLY. HOWEVER...SCT CONVECTION HAS DEVELOPED OVER
DEEP E TX INTO N LA/SW AR EARLY THIS AFTERNOON...WITH THIS TREND
EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON
AFFECTING ALL BUT THE TYR AND POSSIBLY TXK TERMINAL. LOCALLY GUSTY
WINDS...MVFR CIGS/REDUCED VSBYS...AND SVR TURBULENCE WILL BE
POSSIBLE IN/NEAR THE CONVECTION...BEFORE THEY DIMINISH SHORTLY
AFTER SUNSET. SHOULD SEE SOME CONVECTIVE DEBRIS LINGER THIS
EVENING...WITH MVFR CIGS EXPECTED TO REDEVELOP/SPREAD N AFTER 06Z
OVER MUCH OF THE REGION. A MCS IS EXPECTED TO DEVELOP LATE THIS
AFTERNOON OVER WCNTRL OK...AND PROGRESS ESE INTO SE OK/EXTREME NE
TX SHORTLY AFTER 06Z...BUT SHOULD GRADUALLY WEAKEN WITH TIME AS IT
ENCOUNTERS A MORE STABLE AIR MASS. HOWEVER...THIS CONVECTION MAY
AFFECT THE TYR/GGG/TXK TERMINALS BETWEEN 09-12Z SUNDAY...AND
SHV/ELD AROUND/SHORTLY AFTER 12Z. HAVE INSERTED MENTION OF VCTS
FOR THESE TERMINALS...WITH ANY ASSOCIATED MESOSCALE BNDRYS
POSSIBLY SCOURING THE LOWER CIGS...ALLOWING FOR A QUICKER RETURN
OF VFR CIGS. THESE SFC BNDRYS MAY EVENTUALLY FOCUS ADDITIONAL SCT
CONVECTION DURING THE AFTERNOON FARTHER SE ACROSS THE
REGION...WITH MVFR CIGS AHEAD OF THE DECAYING COMPLEX EXPECTED TO
LIFT/BECOME VFR BY LATE MORNING. S WINDS 10-15KTS...WITH GUSTS TO
23KTS OVER E TX/SE OK...WILL DIMINISH SLIGHTLY TO 6-12KTS AFTER
00Z. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 82 69 84 / 60 70 40 40
MLU 72 83 70 84 / 50 70 50 40
DEQ 69 80 67 79 / 70 60 30 30
TXK 70 82 68 80 / 70 60 30 30
ELD 71 81 68 80 / 60 70 40 30
TYR 72 82 69 83 / 60 60 40 40
GGG 72 82 69 84 / 60 70 40 40
LFK 74 83 71 86 / 50 70 50 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR ARZ050-051-059-060-
070.
LA...NONE.
OK...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR OKZ077.
TX...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR TXZ096-097-108>112-
124>126-136>138.
&&
$$
06
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
531 AM EDT SUN MAY 17 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EDT SUN MAY 17 2015
WATER VAPOR LOOP AND RAP ANALYSIS REVEALS WELL-DEFINED SHORTWAVE
LIFTING NORTH THROUGH THE CENTRAL PLAINS WITH PLUME OF DEEP GULF
MOISTURE STREAMING NORTH AHEAD OF IT. SFC ANALYSIS SHOWS DEWPOINTS
REACHING INTO THE LOWER 60S AS FAR NORTH AS HAYWARD AND SIREN WI.
LOWERING HEIGHT FALLS AHEAD OF THE APPROACHING SHORTWAVE COMBINED
WITH THE DEEPENING MOISTURE AND BUILDING INSTABILITY WILL PROVIDE
THE FOCUS FOR SHRA/TSRA OVER NW WI INTO UPPER MI LATER THIS
AFTERNOON INTO THIS EVENING.
TODAY AND TONIGHT...MODELS SHOW APPROACHING SHORTWAVE LIFTING NE
FROM THE CENTRAL PLAINS INTO THE UPPER LAKES BY THIS EVENING. THIS
WAVE SHOULD SPREAD SHRA/TSRA INTO THE AREA THIS AFTN AND EVENING AS
40-50 KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN
1.5 INCHES TRANSLATES E. MODEL FCST DEEP LAYER SHEAR OF 40 TO 45 KTS
COULD SUPPORT WELL ORGANIZED STRONG STORMS AND ENHANCE SEVERE TSTM
RISK. HOWEVER...AMOUNT OF INSTABILITY REMAINS IN QUESTION AS
INCREASING CLOUD COVER AHEAD OF THE SHORTWAVE COULD SUPRESS
INSTABILITY. THE GFS...CANADIAN AND RAP MODELS INDICATE MLCAPE
VALUES OF 400-800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON
COUNTIES BY THIS EVENING (00Z MON) AS NEW SPC DAY1 CONVECTIVE
OUTLOOK CONTINUES TO TARGET THESE COUNTIES AS WELL AS OTHER AREAS
ALONG THE WI BORDER FOR A SLIGHT RISK OF SVR STORMS THIS AFTERNOON
INTO THIS EVENING. THE MAIN THREATS FOR ISOLD SEVERE STORMS WOULD BE
LARGE HAIL AND DAMAGING WINDS. HIGH TEMPS WELL INTO THE 70S WILL BE
COMMON OVER THE W HALF OF THE FCST AREA TODAY WITH PERHAPS A FEW
LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE MICHIGAN
SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH COOLER
(AROUND 60F) ALONG SHORELINE.
EXPECT DIMINISHING SHRA/TSRA TO SPREAD E THRU THE EVENING AS
INSTABILITY WANES...AND THEN MOST OF THE AREA WILL PROBABLY BE DRY
OVERNIGHT. FOG COULD BECOME WIDESPREAD AND POSSIBLY DENSE LATER
TONIGHT OVER THE EAST HALF WITH ADDED MOISTURE FM DEPARTING SHRA AND
CONTINUED MOIST SSW FLOW OFF LAKE MICHIGAN. COULD ALSO BE SOME
UPSLOPE DZ INTO ERN ZONES LATE TONIGHT INTO MON MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 407 AM EDT SUN MAY 17 2015
AS HAS BEEN TALKED ABOUT FOR SEVERAL DAYS...SPLIT FLOW WILL PERSIST
ACROSS THE CONTINENT FOR THE FORESEEABLE FUTURE...WITH STRONG
POSITIVE HEIGHT ANOMALIES ACROSS NW CANADA. THIS SHOULD KEEP THE
UPPER GREAT LAKES IN STRONGLY CONFLUENT FLOW FOR MUCH OF THE
FORECAST PERIOD BEYOND TUESDAY...YIELDING A DRY FORECAST INTO
MEMORIAL DAY WEEKEND.
AS FOR MONDAY...THE NWP ARE IN GOOD AGREEMENT IN SHOWING THE
OCCLUDED FRONT MOVING ACROSS THE AREA DURING THE MORNING HOURS. WITH
THE AREA BEING IN THE DRY SLOT IN THE MORNING AND STRONG
MID LEVEL Q-VECTOR DIVERGENCE...EXPECT ANY PRECIPITATION TO BE
CONFINED TO NEAR LAKE MICHIGAN WHERE MOIST ONSHORE FLOW WILL KEEP
CHANCES OF DRIZZLE/FOG IN THE MORNING HOURS BEFORE THE WINDS TURN
WESTERLY. BEHIND THE FRONT...COMMA HEAD MOISTURE WILL ATTEMPT TO
WRAP INTO THE AREA...BUT THE DEEPER MOISTURE WILL REMAIN OVER FAR
WESTERN LAKE SUPERIOR INTO MINNESOTA UNTIL LATE IN THE DAY INTO THE
OVERNIGHT HOURS. COULD BE A PASSING SHOWER MONDAY AFTERNOON ACROSS
THE WEST AND KEWEENAW AS THE DEEPER MOISTURE WRAPS IN BEHIND THE
FILLING AREA OF LOW PRESSURE AND INCREASING UPSLOPE FLOW DUE TO NW
WINDS. STRONG COLD ADVECTION AS THE UPPER TROUGH MOVES EAST OF THE
AREA WILL ALLOW FOR 850MB TEMPS TO DROP TO -9C ACROSS MUCH OF THE
AREA. THIS COMBINED WITH NW FLOW WILL ALLOW FOR ANY RAIN SHOWERS TO
CHANGE TO SNOW AND PERHAPS INCREASE IN AREAL COVERAGE ACROSS THE
WESTERN PART OF UPPER MICHIGAN. DUE TO THE COLD TEMPERATURES AND
PRECIPITATION OCCURING DURING THE OVERNIGHT HOURS...COULD NOT
TOTALLY RULE OUT A DUSTING TO LOCALLY AN INCH OVER GRASSY AREAS
MONDAY NIGHT INTO TUESDAY MORNING BUT GIVEN THE LACK OF SIGNIFICANT
SYNOPTIC SUPPORT DUE TO THE BEST UPPER ENERGY REMAINING WEST AND
NORTH OF THE AREA...DO NOT EXPECT ANY MORE THAN THAT AT THIS TIME.
COLD AND WINDY DAY ON TUESDAY WITH DRYING ACROSS THE ENTIRE AREA
LIKELY CAUSING ANY PRECIPITATION NEAR LAKE SUPERIOR TO SUBSIDE
DURING THE AFTERNOON HOURS. STILL...IT WILL BE QUITE RAW WITH
TEMPERATURES 15-20 DEGREES BELOW NORMAL.
HEIGHTS BEGIN TO RISE ON WEDNESDAY AS THE UPPER RIDGE OVER THE
WRN ATLC BREAKS DOWN SLIGHTLY...ALLOWING THE LONG WAVE TROUGH OVER
THE REGION TO SHIFT EAST. THIS WILL ALLOW FOR SOME MODEST WARMING AT
850MB TO +4C BY WED EVENING ...WHICH COMBINED WITH THE SUNSHINE
SHOULD ALLOW FOR TEMPS TO GET AT LEAST INTO THE 50S OR LOWER 60S ON
WEDNESDAY....BUT STILL BELOW NORMAL FOR THIS TIME OF YEAR. CONTINUED
WARMING ON THURSDAY AHEAD OF AN UPPER DISTURBANCE ROTATING AROUND
THE UPPER LOW OVER NW QUEBEC. THE GFS AND ECMWF SUGGEST THIS UPPER
DISTURBANCE WILL CLIP THE UPPER GREAT LAKES THU NIGHT...HOWEVER
GIVEN THE VERY DRY AIRMASS IN PLACE ACROSS THE REGION NO
PRECIPITATION IS EXPECTED. WILL GO WITH SLIGHTLY COOLER TEMPS FRIDAY
AS 850MB TEMPS DROP BACK TO -1C. WARMER ON SATURDAY AND STILL DRY AS
HEIGHTS RISE ONCE AGAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 135 AM EDT SUN MAY 17 2015
ALL SITES ARE CURRENTLY VFR...BUT A TRICKY FORECAST FOR
THE OVERNIGHT AND SUNDAY TIME PERIODS. STRATUS AND SOME FOG WILL
DEVELOP OVERNIGHT TONIGHT...ESPECIALLY AT SAW WITH UPSLOPE FLOW OFF
LAKE MICHIGAN AT SAW AND POSSIBLY AT KCMX WITH UPSLOPE EASTERLY FLOW
OFF LAKE SUPERIOR. STRATUS SHOULD EVEN MAKE IT TO IWD LATE TONIGHT.
LOW CEILINGS SHOULD MIX OUT AT CMX AND MAYBE EVEN IWD DURING THE DAY
TOMORROW BUT PERSISTENT UPSLOPE FLOW WILL KEEP LOW CLOUDS AT SAW FOR
MUCH OF THE DAY. SHOWER AND ISOLATED THUNDER CHANCES WILL INCREASE
FROM WEST TO EAST THROUGH THE DAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 519 AM EDT SUN MAY 17 2015
LOW PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY
INCREASING E TO SE FLOW TODAY. GUSTS COULD REACH AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS CENTRAL AND EAST. WARM AND MOIST AIR
SURGING NORTH AHEAD OF THE LOW WILL KEEP FOG IN THE FORECAST THROUGH
AT LEAST MONDAY MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS
OUT THE FOG. FOG COULD GET DENSE LATER TONIGHT INTO MONDAY MORNING
OVER THE EAST HALF OF THE LAKE WITH ADDED MOISTENING FROM SHRA
MOVING ACROSS AREA. THE LOW WILL CROSS LAKE SUPERIOR MONDAY AND
MONDAY EVENING. THIS WILL USHER IN NW TO NNW WINDS OF 20 TO 30 KTS
MONDAY NIGHT AND TUESDAY...MAINLY NCNTRL AND EAST HALF. BROAD HIGH
PRESSURE WILL THEN BUILD ACROSS THE REGION WEDNESDAY THROUGH
FRIDAY...BRINGING WINDS DOWN BLO 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR LMZ248-
250.
&&
$$
SHORT TERM...VOSS
LONG TERM...MRD
AVIATION...MZ
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EDT SUN MAY 17 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 519 AM EDT SUN MAY 17 2015
WATER VAPOR LOOP AND RAP ANALYSIS REVEALS WELL-DEFINED SHORTWAVE
LIFTING NORTH THROUGH THE CENTRAL PLAINS WITH PLUME OF DEEP GULF
MOISTURE STREAMING NORTH AHEAD OF IT. SFC ANALYSIS SHOWS DEWPOINTS
REACHING INTO THE LOWER 60S AS FAR NORTH AS HAYWARD AND SIREN WI.
LOWERING HEIGHT FALLS AHEAD OF THE APPROACHING SHORTWAVE COMBINED
WITH THE DEEPENING MOISTURE AND BUILDING INSTABILITY WILL PROVIDE
THE FOCUS FOR SOME SHRA/TSRA OVER NW WI INTO UPPER MI LATER THIS
AFTERNOON INTO THIS EVENING.
TODAY AND TONIGHT...MODELS SHOW APPROACHING SHORTWAVE LIFTING NE
FROM THE CENTRAL PLAINS INTO THE UPPER LAKES BY THIS EVENING. THIS
WAVE SHOULD SPREAD SHRA/TSRA INTO THE AREA THIS AFTN AND EVENING AS
40-50 KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN
1.5 INCHES TRANSLATES E. MODEL FCST DEEP LAYER SHEAR OF 40 TO 45 KTS
COULD SUPPORT WELL ORGANIZED STRONG STORMS AND ENHANCE SEVERE TSTM
RISK. HOWEVER...AMOUNT OF INSTABILITY REMAINS IN QUESTION AS
INCREASING CLOUD COVER AHEAD OF THE SHORTWAVE COULD SUPRESS
INSTABILITY. THE GFS...CANADIAN AND RAP MODELS INDICATE MLCAPE
VALUES OF 400-800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON
COUNTIES BY THIS EVENING (00Z MON) AS NEW SPC DAY1 CONVECTIVE
OUTLOOK CONTINUES TO TARGET THIS COUNTIES AS WELL AS OTHER AREAS
ALONG THE W BDR FOR A SLIGHT RISK OF SVR STORMS THIS AFTERNOON INTO
THIS EVENING. THE MAIN THREATS FROM ISOLD SEVERE STORMS WOULD BE
LARGE HAIL AND DAMAGING WINDS. HIGH TEMPS WELL INTO THE 70S WILL BE
COMMON OVER THE W HALF OF THE FCST AREA TODAY WITH PERHAPS A FEW
LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE MICHIGAN
SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH COOLER
(AROUND 60F) ALONG SHORELINE.
EXPECT DIMINISHING SHRA/TSRA TO SPREAD E THRU THE EVENING AS
INSTABILITY WANES...AND THEN MOST OF THE AREA WILL PROBABLY BE DRY
OVERNIGHT. FOG COULD BECOME WIDEPREAD AND POSSIBLY DENSE LATER
TONIGHT OVER THE EAST HALF WITH ADDED MOISTURE FM DEPARTING SHRA AND
CONTINUED MOIST SSW FLOW OFF LAKE MICHIGAN. COULD ALSO BE SOME
UPSLOPE DZ INTO ERN ZONES LATE TONIGHT INTO MON MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 407 AM EDT SUN MAY 17 2015
AS HAS BEEN TALKED ABOUT FOR SEVERAL DAYS...SPLIT FLOW WILL PERSIST
ACROSS THE CONTINENT FOR THE FORESEEABLE FUTURE...WITH STRONG
POSITIVE HEIGHT ANOMALIES ACROSS NW CANADA. THIS SHOULD KEEP THE
UPPER GREAT LAKES IN STRONGLY CONFLUENT FLOW FOR MUCH OF THE
FORECAST PERIOD BEYOND TUESDAY...YIELDING A DRY FORECAST INTO
MEMORIAL DAY WEEKEND.
AS FOR MONDAY...THE NWP ARE IN GOOD AGREEMENT IN SHOWING THE
OCCLUDED FRONT MOVING ACROSS THE AREA DURING THE MORNING HOURS. WITH
THE AREA BEING IN THE DRY SLOT IN THE MORNING AND STRONG
MID LEVEL Q-VECTOR DIVERGENCE...EXPECT ANY PRECIPITATION TO BE
CONFINED TO NEAR LAKE MICHIGAN WHERE MOIST ONSHORE FLOW WILL KEEP
CHANCES OF DRIZZLE/FOG IN THE MORNING HOURS BEFORE THE WINDS TURN
WESTERLY. BEHIND THE FRONT...COMMA HEAD MOISTURE WILL ATTEMPT TO
WRAP INTO THE AREA...BUT THE DEEPER MOISTURE WILL REMAIN OVER FAR
WESTERN LAKE SUPERIOR INTO MINNESOTA UNTIL LATE IN THE DAY INTO THE
OVERNIGHT HOURS. COULD BE A PASSING SHOWER MONDAY AFTERNOON ACROSS
THE WEST AND KEWEENAW AS THE DEEPER MOISTURE WRAPS IN BEHIND THE
FILLING AREA OF LOW PRESSURE AND INCREASING UPSLOPE FLOW DUE TO NW
WINDS. STRONG COLD ADVECTION AS THE UPPER TROUGH MOVES EAST OF THE
AREA WILL ALLOW FOR 850MB TEMPS TO DROP TO -9C ACROSS MUCH OF THE
AREA. THIS COMBINED WITH NW FLOW WILL ALLOW FOR ANY RAIN SHOWERS TO
CHANGE TO SNOW AND PERHAPS INCREASE IN AREAL COVERAGE ACROSS THE
WESTERN PART OF UPPER MICHIGAN. DUE TO THE COLD TEMPERATURES AND
PRECIPITATION OCCURING DURING THE OVERNIGHT HOURS...COULD NOT
TOTALLY RULE OUT A DUSTING TO LOCALLY AN INCH OVER GRASSY AREAS
MONDAY NIGHT INTO TUESDAY MORNING BUT GIVEN THE LACK OF SIGNIFICANT
SYNOPTIC SUPPORT DUE TO THE BEST UPPER ENERGY REMAINING WEST AND
NORTH OF THE AREA...DO NOT EXPECT ANY MORE THAN THAT AT THIS TIME.
COLD AND WINDY DAY ON TUESDAY WITH DRYING ACROSS THE ENTIRE AREA
LIKELY CAUSING ANY PRECIPITATION NEAR LAKE SUPERIOR TO SUBSIDE
DURING THE AFTERNOON HOURS. STILL...IT WILL BE QUITE RAW WITH
TEMPERATURES 15-20 DEGREES BELOW NORMAL.
HEIGHTS BEGIN TO RISE ON WEDNESDAY AS THE UPPER RIDGE OVER THE
WRN ATLC BREAKS DOWN SLIGHTLY...ALLOWING THE LONG WAVE TROUGH OVER
THE REGION TO SHIFT EAST. THIS WILL ALLOW FOR SOME MODEST WARMING AT
850MB TO +4C BY WED EVENING ...WHICH COMBINED WITH THE SUNSHINE
SHOULD ALLOW FOR TEMPS TO GET AT LEAST INTO THE 50S OR LOWER 60S ON
WEDNESDAY....BUT STILL BELOW NORMAL FOR THIS TIME OF YEAR. CONTINUED
WARMING ON THURSDAY AHEAD OF AN UPPER DISTURBANCE ROTATING AROUND
THE UPPER LOW OVER NW QUEBEC. THE GFS AND ECMWF SUGGEST THIS UPPER
DISTURBANCE WILL CLIP THE UPPER GREAT LAKES THU NIGHT...HOWEVER
GIVEN THE VERY DRY AIRMASS IN PLACE ACROSS THE REGION NO
PRECIPITATION IS EXPECTED. WILL GO WITH SLIGHTLY COOLER TEMPS FRIDAY
AS 850MB TEMPS DROP BACK TO -1C. WARMER ON SATURDAY AND STILL DRY AS
HEIGHTS RISE ONCE AGAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 135 AM EDT SUN MAY 17 2015
ALL SITES ARE CURRENTLY VFR...BUT A TRICKY FORECAST FOR
THE OVERNIGHT AND SUNDAY TIME PERIODS. STRATUS AND SOME FOG WILL
DEVELOP OVERNIGHT TONIGHT...ESPECIALLY AT SAW WITH UPSLOPE FLOW OFF
LAKE MICHIGAN AT SAW AND POSSIBLY AT KCMX WITH UPSLOPE EASTERLY FLOW
OFF LAKE SUPERIOR. STRATUS SHOULD EVEN MAKE IT TO IWD LATE TONIGHT.
LOW CEILINGS SHOULD MIX OUT AT CMX AND MAYBE EVEN IWD DURING THE DAY
TOMORROW BUT PERSISTENT UPSLOPE FLOW WILL KEEP LOW CLOUDS AT SAW FOR
MUCH OF THE DAY. SHOWER AND ISOLATED THUNDER CHANCES WILL INCREASE
FROM WEST TO EAST THROUGH THE DAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 519 AM EDT SUN MAY 17 2015
LOW PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY
INCREASING E TO SE FLOW TODAY. GUSTS COULD REACH AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS CENTRAL AND EAST. WARM AND MOIST AIR
SURGING NORTH AHEAD OF THE LOW WILL KEEP FOG IN THE FORECAST THROUGH
AT LEAST MONDAY MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS
OUT THE FOG. FOG COULD GET DENSE LATER TONIGHT INTO MONDAY MORNING
OVER THE EAST HALF OF THE LAKE WITH ADDED MOISTENING FROM SHRA
MOVING ACROSS AREA. THE LOW WILL CROSS LAKE SUPERIOR MONDAY AND
MONDAY EVENING. THIS WILL USHER IN NW TO NNW WINDS OF 20 TO 30 KTS
MONDAY NIGHT AND TUESDAY...MAINLY NCNTRL AND EAST HALF. BROAD HIGH
PRESSURE WILL THEN BUILD ACROSS THE REGION WEDNESDAY THROUGH
FRIDAY...BRINGING WINDS DOWN BLO 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR LMZ248-
250.
&&
$$
SHORT TERM...VOSS
LONG TERM...MRD
AVIATION...MZ
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
359 AM EDT SUN MAY 17 2015
.SHORT TERM...TODAY AND TONIGHT
LIGHT WINDS...BREAKS IN THE CLOUDS...AND RAINFALL YESTERDAY HAVE ALL
SET THE STAGE FOR FOG AND STRATUS TO FORM ONCE AGAIN THIS MORNING.
SO FAR VISIBILITIES HAVE PREDOMINANTLY RANGED FROM 1-5 MILES. THE
ARRIVAL OF ADDITIONAL CLOUDS SHOULD HELP PREVENT WIDESPREAD DENSE
FOG...BUT PATCHES ARE CERTAINLY POSSIBLE. WILL CONTINUE TO MONITOR
DENSE FOG POTENTIAL THROUGH THE MORNING HOURS HOWEVER.
UPPER RIDGE STILL REMAINS OVER THE SOUTHEAST CONUS...WITH LOWER
MICHIGAN POSITIONED ON THE WESTERN PERIPHERY. THE RIDGE AXIS WILL
SHIFT EAST TODAY AS THE LARGE UPPER TROUGH OVER THE CENTRAL U.S.
BEGINS TO LIFT TOWARDS THE UPPER MIDWEST. THE INFLUENCE OF THE RIDGE
WILL CONTINUE TO PROVIDE A STABILIZING INFLUENCE OVER THE AREA
THROUGH THE MORNING HOURS...WITH THERMAL PROFILES ON GFS/NAM
FORECAST SOUNDINGS STILL SHOWING WEAK LAPSE RATES IN THE MID-LEVELS
ASSOCIATED WITH THE WARMER AIR ALOFT. POTENTIAL FOR CONVECTION
THROUGH THE EARLY PART OF THE DAY LOOKS LIMITED THEREFORE...BUT
STILL POSSIBLE ALONG A FEW FEATURES. FRONTAL BOUNDARY REMAINS DRAPED
ACROSS CENTRAL LOWER MICHIGAN AS OF 300 AM THIS MORNING. THIS FRONT
WILL LIFT NORTHWARD THROUGH THE LATE MORNING AS SOUTHERLY FLOW
INCREASES AHEAD OF THE APPROACHING UPPER TROUGH. THE FRONT COULD
PROVIDE A FOCUS THIS MORNING FOR A FEW SHOWERS OR EVEN A TSTORM TO
FORM OVER THE SAGINAW VALLEY AND THUMB. FURTHER SOUTH IN THE WARM
SECTOR...UPPER SHORTWAVE MOVING EAST THROUGH THE OHIO VALLEY COULD
TRIGGER A FEW SHOWERS/TSTORMS NEAR THE BORDER.
AIRMASS WILL REMAIN VERY MOIST TODAY/TONIGHT WITH DEWPOINTS IN THE
60S. TEMPERATURES IN THE MID-LEVELS WILL MEANWHILE COOL SLIGHTLY
THROUGH THE DAY AS THE UPPER RIDGE AXIS PULLS EAST...WHILE THE
SURFACE LAYER HEATS TO AROUND 80F THIS AFTERNOON. AS THIS
OCCURS...WILL SEE INSTABILITY INCREASE THROUGH THE DAY AND BECOME
SURFACE BASED...WITH A PARCEL OF 80/65 YIELDING ABOUT 1000 J/KG OF
CAPE DURING THE LATE AFTERNOON. SEVERE WEATHER IS NOT EXPECTED
THROUGH LATE AFTERNOON AS SHEAR VALUES LOOK UNIMPRESSIVE AND CAPE
LOOKS TALL/SKINNY. VERY HEAVY DOWNPOURS WILL CONTINUE TO BE POSSIBLE
AS PW VALUES RISE FROM 1.5 INCHES THIS MORNING TO AROUND 1.75 INCHES
TONIGHT. WILL NEED TO FIND A TRIGGER FOR CONVECTION IN THE WARM
SECTOR TODAY/TONIGHT IN ORDER TO GET ANYTHING OTHER THAN JUST A FEW
CELLS POPPING UP HOWEVER. LOOKING BACK AT OBSERVATIONAL AND MODEL
DATA OVER THE CONUS FROM YESTERDAY...IT APPEARS AN OLD WARM FRONT
WAS CAST OFF THE SYSTEM OVER THE SOUTHERN/CENTRAL PLAINS EARLY
YESTERDAY. CURRENT OBSERVATIONS OVER SOUTEHRN ILLINOIS/INDIANA DO
INDICATE A SLIGHT "KINK" IN THE FLOW. THIS IS WHERE NAM/GFS MODELS
CURRENTLY PLACE THIS FEATURE...AND THEY BOTH LIFT IT THROUGH
SOUTHEAST MICHIGAN BETWEEN 14-22Z (PER THERMAL FIELDS AND HIGHER
THETA-E ADVECTION). COVERAGE OF SHOWERS/TSTORMS THAT COULD DEVELOP
AS THIS SUBTLE FEATURE WORKS THROUGH IS UNCERTAIN HOWEVER AS THE
ATMOSPHERE REMAINS JUICY BUT NOT OVERLY BUOYANT. KEPT COVERAGE AT
CHANCE AS HIGHER-RES RUNS OF THE 4KM WRF AND THE HRRR DO NOT SEEM
TOO KEEN ON WIDESPREAD CONVECTION DEVELOPING UNDER THE MORE STABLE
INFLUENCE OF THE RIDGE DEPARTING TO OUR EAST.
WHILE THE MAIN COLD FRONT FROM THIS SYSTEM WILL NOT PUSH THROUGH THE
AREA UNTIL MONDAY NIGHT...WHAT IS LEFT OF THE WEAKENING FRONT NOW
EXTENDING FROM MINNESOTA DOWN INTO TEXAS WILL WORK EAST ACROSS LOWER
MICHIGAN TONIGHT. THIS SHOULD PROVIDE A BETTER FOCUS FOR
SHOWERS/TSTORMS. HIGHER RES RUNS CONTINUE TO SHOW THE CURRENT LINE
OF CONVECTION BREAKING...WITH MOST OF THE ACTIVITY LIFTING TO OUR
WEST AND NORTH...ONLY CLIPPING THE SAGINAW VALLEY. STILL...BETTER
INSTABILITY ARRIVING OVERNIGHT (ELEVATED) WARRANTS CHANCE-LIKELY
POPS AS IT WORKS THROUGH.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
DEEP LAYER SOUTHWESTERLY FLOW FIRMLY IN PLACE ON MONDAY WITH THE
REGION STILL LARGELY OUTSIDE THE MAIN HEIGHT FALL CENTER AND
ASSOCIATED UPPER JET CORE ATTENDANT TO THE CLOSED LOW MEANDERING
ACROSS NORTHERN MN. LEAD TROUGH AXIS TRANSLATING THROUGH TONIGHT
WILL SHUNT THE DEEPEST MOISTURE PLUME TO THE EAST BY MONDAY MORNING.
THE OVERALL REDUCTION IN MOISTURE QUALITY AND LACK OF AN APPARENT/
NECESSARY FORCING MECHANISM WITHIN THIS WELL MIXED WARM SECTOR
ENVIRONMENT WILL CONTAIN CONVECTIVE CHANCES PRIOR TO THE COLD
FRONTAL ARRIVAL. ANY EARLY DAY LOW CLOUD DEBRIS WILL MIX OUT...
INCREASING THE LIKELIHOOD FOR SEEING A GOOD BIT OF SUN BY THE MIDDAY
PERIOD. A SOLID LOOKING DIURNAL TEMPERATURE RESPONSE WITH HIGHS
MAKING A RUN INTO THE LOWER AND MIDDLE 80S.
COLD FRONTAL TIMING CENTERING ON THE 21Z-03Z PERIOD MONDAY
EVENING...AN ARRIVAL TIME CERTAINLY FAVORABLE TOWARD CAPITALIZING ON
THE BACK END OF PEAK HEATING. EXISTING ENVIRONMENT LIKELY CARRYING
MLCAPE IN THE BALLPARK OF 1500 J/KG. THIN RIBBON OF HIGHER THETA-E
ANCHORED ON THE BOUNDARY WILL HELP AUGMENT THIS DESTABILIZATION.
THE OVERALL FRONTAL POSITIONING AND TIMING WILL LEAVE A NARROW
WINDOW FOR CONVECTIVE INITIATION TO COMMENCE LOCALLY DURING THE
EVENING...ROUGHLY SOUTHEAST OF A HOWELL TO LAPEER LINE. WHILE THE
STRONGER MID LEVEL WIND FIELD WILL RESIDE BEHIND THE FRONT...SOME
INCREASE IN DEEP LAYER SHEAR WILL OCCUR JUST AS THE FRONT ARRIVES.
MID LEVEL LAPSE RATES REMAIN MODEST...BUT GIVEN THE UNDERLYING LOW
LEVEL THERMODYNAMICS...POTENTIAL WILL EXIST FOR BETTER ORGANIZED
CELLS TO EMERGE WITH AN ACCOMPANYING ISOLATED SEVERE T-STORM RISK.
ENSUING POST-FRONTAL COLD AIR ADVECTION INCREASES HEADING INTO
TUESDAY...WITH 850 MB TEMPERATURES DROPPING A GOOD 15-20 DEGREES IN
24 HOURS. THIS WILL LIKELY TRANSLATE INTO A BROAD STRATOCU FIELD
FOR TUESDAY...WITH TEMPERATURES STRUGGLING TO REACH MUCH ABOVE THE
60 DEGREE MARK. DRY/STABLE PROFILE IN PLACE THROUGH THE MIDWEEK
PERIOD...CONDITIONS DEFINED BY LOW LEVEL ANTICYCLONIC FLOW TUCKED
BENEATH A WEAKLY CONFLUENT WEST-NORTHWEST MID LEVEL PATTERN.
SEASONABLY COOL AIR MASS LEFT TO RESPOND VIA A HIGHER DEGREE OF
INSOLATION ON WEDNESDAY...NO REAL ADVECTIVE COMPONENT IN PLACE.
SLOW MODERATION OF THIS ENVIRONMENT BY THURSDAY/FRIDAY AS UPPER
HEIGHTS START TO REBOUND.
&&
.MARINE...
FAVORABLE MARINE CONDITIONS IN TERMS OF WINDS AND WAVES TO FINISH
THE WEEKEND. THE WARM AND INCREASINGLY HUMID CONDITIONS UNDER LIGHT
WIND WILL CONTINUE TO SUPPORT FOG OVER LAKE HURON THROUGH THE
MORNING HOURS. A MARINE DENSE FOG ADVISORY REMAINS IN EFFECT SOUTH
OF SAGINAW BAY. THIS ENVIRONMENT WILL REMAIN FAVORABLE FOR THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. MODEST
SOUTHWESTERLY WINDS DEVELOP IN ADVANCE OF A COLD FRONT ON MONDAY.
COLD FRONT SWEEPS THROUGH MONDAY EVENING WITH COOLER AND DRIER
CONDITIONS DEVELOPING ON WEST TO NORTHWEST FLOW FOR THE MID WEEK
PERIOD.
&&
.AVIATION...ISSUED 1200 AM EDT SUN MAY 17 2015
WITH SHOWERS ACTIVITY ALONG THE FRONT DYING DOWN...ATTENTION BEGINS
TO SHIFT TOWARD THE FOG POTENTIAL. USING LAST NIGHT AS A GUIDE AS
WELL AS CURRENT TRENDS IN OBS...LOOKS GOOD FOR ALL LOCATIONS TO DROP
TO AT LEAST MVFR FOR VSBY/CIGS WITH IFR LIKELY FOR A FEW HOURS AS
WELL. TIMING THE IFR WILL LIKELY BE THE CHALLENGE AS EARLY ON THERE
IS WIDELY VARYING CONDITIONS ACROSS SE MI. THE FRONT WILL REMAIN
DRAPED ACROSS THE MBS/FNT LOCATIONS WHICH WILL AGAIN LEAD TO CHANCES
OF SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON TODAY...BUT
COVERAGE AND TIMING ILL DEFINED AT THE MOMENT SO WILL HOLD OFF ON
INCLUDING IN THE TAF. BETTER CHANCES FOR PRECIP COMES AROUND 00Z FOR
MBS/FNT AS A PREFRONTAL BOUNDARY WORKS ACROSS THE AREA.
FOR DTW...MVFR FOG ALREADY DEVELOPING OVER THE TERMINAL WITH
POTENTIAL FOR IFR CONDITIONS BY MORNING. AS THE FOG DISSIPATES
THROUGH THE MORNING HOURS...ATTENTION THEN TURNS BACK TO CONVECTIVE
POTENTIAL FOR THE AFTERNOON AND OVERNIGHT HOURS. NOT ENOUGH
CONFIDENCE IN COVERAGE ATTM TO INCLUDE IN THE TAF.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CIGS AOB 5KFT AFTER 09Z.
* LOW FOR VISIBILITY BELOW 1/2 MILE EARLY THIS MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LHZ441>443-462>464.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...HLO
LONG TERM....MR
MARINE.......MR
AVIATION.....DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1156 PM CDT SAT MAY 16 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 332 PM CDT SAT MAY 16 2015
SEVERE POTENTIAL TONIGHT REMAINS THE PRIMARY FORECAST CONCERN.
SCATTERED CONVECTION SUNDAY FOLLOWED BY COOLER TEMPERATURES TO BEGIN
THE WORK WEEK ARE SECONDARY CONCERNS.
18Z SOUNDING AT KOAX SHOWED ALMOST 1500 J/KG OF SURFACE-BASED
CAPE...WHICH IS MUCH LOWER THAN THE 2500 J/KG SHOWN BY OPERATIONAL
RAP ANALYSIS OBSERVED ON SPC MESOANALYSIS PAGE. SOUNDING ALSO SHOWED
ALMOST 50 J/KG OF CONVECTIVE INHIBITION. HOWEVER AXIS OF HIGHEST
CAPE NEAR OUR CWA DEPICTED BY RAP STILL LOOKS GOOD STRETCHING FROM
EASTERN SOUTH DAKOTA INTO WESTERN IOWA WHERE AVERAGE TEMPS AND DEW
POINTS WERE IN THE UPPER 70S AND UPPER 60S. EXPERIMENTAL HRRR
SUGGESTS A FEW STORMS WILL FIRE THIS AFTERNOON FROM SOUTHEAST SOUTH
DAKOTA INTO EASTERN NEBRASKA ON WESTERN SIDE OF INSTABILITY
GRADIENT...AND ALREADY ARE SEEING THE START OF THAT CONVECTION IN
SOUTH DAKOTA AND NEAR THE OMAHA METRO. THESE STORM SHOULD CONTINUE
TO MOVE OFF TO THE NORTHEAST RATHER QUICKLY...AND COULD SEE A
WIND/HAIL EVENT BEFORE EXITING OUR CWA LATE THIS AFTERNOON.
ATTENTION THEN TURNS TO POTENTIALLY MORE WIDESPREAD SEVERE IGNITING
WELL TO OUR SOUTHWEST IN THE HIGHS PLAINS FROM WESTERN NEBRASKA INTO
THE TEXAS PANHANDLE. HI-RES MODELS ALL HAVE SOME VARIATION IN THIS
CONVECTION...AND SPREAD IT INTO SOUTHEAST NEBRASKA LATER THIS
EVENING. WHAT KIND OF ATMOSPHERE WILL BE AVAILABLE FOR THOSE STORMS
IS STILL IN QUESTION...MAINLY DUE TO ON-GOING STORMS IN CENTRAL
KANSAS INTO NORTH CENTRAL OKLAHOMA. THE MOST LIKELY SCENARIO BASED
ON LATEST HRRR AND RAP IS SOME OF THE KANSAS CONVECTION WILL TRACK
NORTHEAST INTO EASTERN NEBRASKA LATE THIS AFTERNOON THEN EXIT TO THE
EAST THIS EVENING. GIVEN CURRENT INSTABILITY AND SHEAR...ROTATING
STORMS ARE LIKELY WITH AT LEAST SOME HAIL THREAT AND MOST NOTABLY
WIND. TORNADOES ARE STILL A THREAT AS WELL IF FORECAST STORM-
RELATIVE 0-1KM HELICITY NEAR 150 M2/S2 IS REALIZED. MODELS DEPICT
THIS AREA OF CONVECTION WILL BOW OUT ACROSS WESTERN IOWA BEFORE
EXITING TO OUR EAST.
THEN SECONDARY SURGE OF STORMS IS SLATED TO RACE NORTHEAST FROM
OKLAHOMA PANHANDLE AND ENTER SOUTHEAST NEBRASKA AT MID TO LATE
EVENING. SOME RECOVERY IN AIRMASS IS LIKELY AFTER EARLIER STORMS. AN
INCREASE IN LOW LEVEL JET TO NEAR 50KT IS LIKELY AS INCREASINGLY
DIFFLUENT MID LEVEL FLOW OVERSPREADS THE PLAINS. SO LATER-EVENING
STORMS WILL STILL HAVE VIGOROUS WIND FIELDS TO PLAY WITH...
SUPPORTING AT LEAST SOME TORNADO AND WIND THREAT PAST DARK. TREND IN
HOURLY UPDATES OF HRRR FORECASTS HAS BEEN FOR NORTHERNMOST SEVERE
STORMS TO ONLY GRAZE FAR SOUTHEAST NEBRASKA IN THE 03Z TO 06Z
TIMEFRAME. SO WILL KEEP A CLOSE EYE ON IF THIS TREND CONTINUES.
WHILE SECOND LINE OF STORMS MOVES EAST OF OUR CWA AFTER
MIDNIGHT...MORE SHOWERS/STORMS ARE FORECAST TO DEVELOP IN WESTERN
NEBRASKA AND TRACK INTO NORTHEAST NEBRASKA OVERNIGHT AS UPPER LOW
MOVES INTO THE NORTHERN PLAINS. A WAVE ROTATING AROUND THIS FEATURE
WILL LIKELY IGNITE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MUCH
OF SUNDAY IN SOUTH DAKOTA AND NORTHERN NEBRASKA. GFS SUGGESTS UP TO
1000 J/KG OF SURFACE-BASED CAPE WILL BE AVAILABLE FOR THIS ACTIVITY
INTO THE AFTERNOON.
AFTER WAVE PASSES SUNDAY AFTERNOON...STRONG COLD ADVECTION WILL
OVERSPREAD OUR AREA...DROPPING 850 TEMPERATURES TO BELOW 0C ON
MONDAY IN OUR NORTH. COULD SEE A PASSING SHOWER ALONG THIS COLD PUSH
SUNDAY NIGHT...BUT THE MAIN WEATHER STORY WILL BE COOLER AND DRIER
AIR BEING PUSHED INTO THE REGION ON BRISK NORTHWEST WINDS MONDAY.
HIGHS IN THE LOWER 60S SHOULD BE ALL WE CAN MUSTER THEN. THE COOL
WEATHER CONTINUES INTO TUESDAY WHEN SURFACE HIGH PRESSURE SETTLES
INTO THE REGION. COULD SEE SUB-40 LOWS IN MANY AREAS TUESDAY MORNING.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CDT SAT MAY 16 2015
MID LEVEL FLOW PATTERN WILL RELOAD AS ANOTHER UPPER LOW SETTLES INTO
THE SOUTHWEST STATES AT MID WEEK ON HEELS OF EXITING NORTHERN PLAINS
LOW. THIS WILL BRING GENERALLY SOUTHWEST FLOW OVER THE MIDDLE OF THE
COUNTRY...WITH A POTENT WAVE EJECTING INTO THE PLAINS ON WEDNESDAY.
THAT WAVE WILL BRING OUR NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
BEGINNING TUESDAY NIGHT BEFORE EXITING WEDNESDAY NIGHT. MOISTURE
RETURN LOOKS MINIMAL...SO SEVERE STORMS APPEAR UNLIKELY DESPITE THE
CALENDAR SAYING WE ARE IN MID TO LATE MAY.
SOME WEAK RIDGING BEHIND EXITING WAVE SUGGESTS RAIN CHANCES WILL BE
AT A MINIMUM TO END THE WEEK...BUT SOUTHWESTERN TROUGH AXIS BEGINS
LIFTING TOWARD THE PLAINS BY SATURDAY. WILL BRING STORM CHANCES BACK
INTO THE FORECAST THEN...BUT DETAILS WILL HAVE TO BE WORKED OUT WITH
TIME ON DEGREE OF POTENTIAL SEVERE RISK.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1142 PM CDT SAT MAY 16 2015
REGIONAL RADAR SHOWING PCPN OVER ERN GRADUALLY SHIFTING NEWD INTO
WRN IA...AND EXPECT LINGERING ACTIVITY AT KOMA/KLNK TO COME TO A
CLOSE WITHIN A COUPLE HOURS. OTHERWISE VFR CONDITIONS WILL PREVAIL
THRU THE FCST PD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...DEE
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1140 PM MDT SAT MAY 16 2015
.AVIATION...
06Z TAF CYCLE
A FEW SPOT SH STILL EXIST BUT WILL QUICKLY COME TO AN END THROUGH
VERY EARLY MORNING ON SUNDAY. VERY LITTLE IMPACT OTHER THAN MTN
TOP OBSCD DUE TO THE PASSING SH. SATELLITE SHOWS ANOTHER BATCH OF
MID/HIGHER LEVEL CLOUDS MAKING THEIR WAY TOWARDS THE FORECAST
AREA. THEY SHOULD ARRIVE LATE TONIGHT AND TRACK OVER THE FORECAST
AREA THROUGH EARLY/MID AFTERNOON. THINKING THAT THERE IS A LESS
LIKELY CHANCE FOR FG/BR DEVELOPMENT AT WESTERN/CENTRAL TERMINAL
SITES SO TOOK OUT MENTION OF VCFG. THIS IS SUPPORTED BY THE LATEST
MODEL GUIDANCE. OTHERWISE VFR CONDITIONS PRETTY MUCH AREAWIDE NEXT
24 HRS. WIND GUSTS WONT BE NEARLY AS STRONG SUNDAY COMPARED TO THE
PREVIOUS FEW DAYS.
50
&&
.PREV DISCUSSION...325 PM MDT SAT MAY 16 2015...
.SYNOPSIS...
PRECIPITATION AND WINDS OVERALL SHOULD DECREASE TONIGHT...WITH QUIET
AND WARMER WEATHER SUNDAY. ANOTHER FRONT AND STORM SYSTEM WILL
COLLIDE BY MONDAY NIGHT AND TUESDAY...WITH ANOTHER WET AND COOLER
PERIOD...ESPECIALLY FOR LOCALES EXTENDING FROM THE RIO GRANDE VALLEY
EASTWARD ACROSS THE EASTERN PLAINS. DRYING EXPECTED THEREAFTER WITH
SOME WARMING BUT SOME STORMS WILL STILL BE POSSIBLE ACROSS AT LEAST
OVER THE FAR EASTERN PLAINS AND NORTHERN MOUNTAINS THE END OF NEXT
WEEK.
&&
.DISCUSSION...
PRECIPITATION AND WINDS OVERALL SHOULD DECREASE OVERNIGHT...BUT WITH
SOME POSSIBLE EXCEPTIONS. WIND ADVY SPOTTY AT BEST THIS AFTERNOON
AND STRONGEST GUSTS APPEAR TO HAVE BEEN CONVECTION
RELATED...HOWEVER...H7 WINDS INCREASE OVERNIGHT OVER PARTS OF THE
NORTHEAST AS THE UPPER LOW/TROF SWINGS OUT INTO THE PLAINS
STATES...SO WILL KEEP THE NPW GOING. WILL ALSO KEEP THE CURRENT WSW
AS IS...WITH GFS/NAM NOT INDICATING MUCH SNOW AFTER 00Z. THE HRRR ON
THE OTHER HAND...KEEPS SOME SNOW GOING OVER THE NRN SANGRE DE CRISTO
MTS...AND THE FORECAST MOIST W-NWLY BOUNDARY LAYER WINDS INTO THE
SANGRES COULD CONTINUE TO ACCUMULATE SOME SNOW INTO THE LATE
EVENING. ARRGH...WILL HAVE TO CONTINUE TO MONITOR...BUT GRIDS HAVE
ANOTHER 1 TO 3 INCHES IN THIS AREA TONIGHT...ALTHOUGH THAT WOULD BE
UNDERDONE IF HRRR IS RIGHT. BUT NO MODEL SEEMS TO BE DOING THAT WELL
TODAY.
DRIER AND WARMER SUNDAY INTO MONDAY. THEN ANOTHER WETTER AND COOLER
PERIOD MONDAY NIGHT THROUGH TUESDAY AS ANOTHER SYSTEM COMING FROM
THE WEST AND A FRONT FROM THE EAST COLLIDE TO PRODUCE WIDESPREAD
PRECIPITATION. TRIMMED DOWN POPULATED QPF WHICH TOTALED A LARGE
SWATH OF A COUPLE OF INCHES JUST MONDAY NIGHT ALONG THE CENTRAL MT
CHAIN TO THE PECOS VALLEY. BUT SOME GENEROUS AMOUNTS POSSIBLE
TUESDAY AS WELL AS THE UPPER SYSTEM SWINGS OVER NE NM. H7 TEMPS NOT
AS COLD AS WITH PRESENT SYSTEM SO NOT ANTICIPATING THE LOWER SNOW
LEVELS THAT HAVE BEEN OBSERVED TODAY.
LOTS OF VARIATION MID TO LATE NEXT WEEK...THE GFS IS DRIER AND WINDY
WHILE THE ECMWF IS WETTER THANKS TO A FRONT ON FRIDAY...SURPRISE. IN
ANY EVENT...THE UNSETTLED WEATHER PATTERN APPEARS TO CONTINUE INTO
THE MEMORIAL DAY WEEKEND.
&&
.FIRE WEATHER...
NO WIDESPREAD FIRE WEATHER CONCERNS THROUGH THE FORECAST PERIOD AS
THE WEATHER PATTERN CONTINUES TO FAVOR UNSETTLED...ACTIVE WEATHER
AND SEASONABLY COOLER THAN NORMAL TEMPERATURES.
CURRENT UPPER LEVEL TROUGH IS CROSSING NM THIS PM AND WILL SHIFT TO
THE EAST TONIGHT. SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
THE EVENING HOURS...MAINLY NORTH OF I 40. SHOWERS MAY LINGER OVER
THE NORTH LATE TONIGHT. RH RECOVERIES WILL BE GOOD TO EXCELLENT.
A MAINLY DRY DAY IS IN STORE SUNDAY AS A WEAK UPPER LEVEL RIDGE
MOVES OVER. DESPITE THE RIDGE...HIGH TEMPERATURES REMAIN BELOW
AVERAGE FOR MID MAY. MODELS INDICATING RESIDUAL MOISTURE WILL
COMBINE WITH DAYTIME HEATING TO PRODUCE A FEW SHOWERS AND MAYBE
THUNDERSTORMS OVER THE NORTHERN MOUNTAINS.
A BACK DOOR COLD FRONT WILL DROP SOUTH INTO THE NORTHEAST EAST
SUNDAY NIGHT. IT WILL STALL MONDAY BEFORE RACING SOUTH AND WEST
MONDAY NIGHT. STRONG EAST WINDS INTO THE RIO GRANDE VALLEY ARE
POSSIBLE. MEANWHILE THE NEXT UPPER LEVEL TROUGH WILL BE APPROACHING
MONDAY THEN SWEEP ACROSS THE STATE MONDAY NIGHT INTO TUESDAY. THE
COMBINATION OF LOW LEVEL MOISTURE BEHIND THE FRONT...INSTABILITY
FROM THE UPPER TROUGH...AND DEEP MOISTURE GETTING DRAWN NORTHWEST
INTO NM FROM TX WILL RESULT IN A SIGNIFICANT RAIN EVENT FOR MUCH OF
THE FORECAST AREA...WITH THE LEAST FAVORED AREA THE SOUTHWEST AND
THE MOST FAVORED AREA ALL OF THE EAST. ALL THE MODELS HAVE A FAIRLY
WIDESPREAD...SOAKING RAIN EVENT WITH ONE TO TWO INCH RAIN AMOUNTS
FOR THE EASTERN PLAINS AND LOCALLY UP TO THREE INCHES IN THE MONDAY
NIGHT THROUGH TUESDAY TIME PERIODS.
YET ANOTHER STORM WILL BE ORGANIZING OFF THE CA COAST LATER NEXT
WEEK. THE FAR EASTERN PLAINS WILL BE UNDER THE GUN FOR SHOWERS AND
STORMS WEDNESDAY INTO FRIDAY. A DRY LINE WILL WOBBLE BACK WEST AT
NIGHT AND TO THE EAST DURING THE DAY. ELSEWHERE SHOULD BE MOSTLY
DRY. ALL AREAS WILL REMAIN BELOW NORMAL. WINDS WILL BE ON THE
INCREASE NEXT FRIDAY AND SATURDAY. BRIEF CRITICAL FIRE WEATHER
CONDITIONS ARE NOT OUT OF THE QUESTION OVER THE SOUTHERN PORTION
OF THE MIDDLE RIO GRANDE VALLEY FRIDAY AFTERNOON.
A PORTION OF THE ABOVE MENTIONED STORM WILL CROSS NM SATURDAY WHILE
ANOTHER PORTION HANGS BACK OVER UT AND AZ. THIS LAZY TROUGH WILL
INCH ITS WAY EAST WHILE KEEPING SHOWERS AND STORMS IN THE FORECAST
FOR THE NORTH AND EAST LATE NEXT WEEKEND INTO EARLY THE FOLLOWING
WEEK. 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
118 AM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 117 AM CDT SUN MAY 17 2015
THIS UPDATE HAVE TAKEN MENTION OF HEAVY RAIN FOR THE REST OF THE
OVERNIGHT HOURS. SHOWERS AND THUNDERSTORM COVERAGE CONTINUED TO
DIMINISH IN SOUTHERN COUNTIES...WITH SCATTERED TO ISOLATED
SHOWERS/THUNDER IN THE JAMES RIVER BASIN TO THE TURTLE MOUNTAINS.
MORE SCATTERED TO WIDESPREAD RAIN SHOWERS OVER NORTHWEST AND NORTH
CENTRAL. THE UPPER LEVEL LOW OVER EASTERN MONTANA/WYOMING KEEPS A
SOUTHERLY FLOW ALOFT OVER THE DAKOTAS...WITH UPPER LEVEL ENERGY
IMPULSES MOVING NORTHWARD INTO NORTH DAKOTA. THROUGHOUT THE
OVERNIGHT HOURS THE UPPER LEVEL LOW IS FORECAST TO MOVE/DEVELOP
EASTWARD INTO CENTRAL SOUTH DAKOTA AND A MORE POTENT SURGE OF UPPER
LEVEL ENERGY IS FORECAST TO DEVELOP INTO EASTERN SOUTH DAKOTA AND
MOVE INTO EASTERN NORTH DAKOTA BEFORE DAYBREAK. THEREFORE STILL
EXPECTING ANOTHER ROUND OF SHOWERS TO BECOME MORE NUMEROUS MAINLY IN
THE JAMES RIVER VALLEY TO BISMARCK. OTHERWISE CURRENT WINDS AND
TEMPERATURES ARE ON TRACK.
UPDATE ISSUED AT 1044 PM CDT SAT MAY 16 2015
MAIN UPDATES HAVE BEEN TO SHOW THE DIMINISHING RAIN TREND FOR THE
NEXT SEVERAL HOURS AS PER THE HRRR. ADDITIONAL RAIN CHANCES ARRIVE
LATER TONIGHT INTO SUNDAY AS THE SURFACE LOW LIFTS TOWARDS EASTERN
NORTH DAKOTA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM CDT SAT MAY 16 2015
CONCERNS THIS FORECAST PERIOD INCLUDE SEVERE WEATHER POSSIBILITY
AND HEAVY RAIN. BY THE END OF THE SHORT TERM THE TRANSITION TO
MUCH COOLER WEATHER WITH SOME SNOW BEGINS TO BE SEEN.
AT 230 PM CDT...SURFACE LOW PRESSURE WAS CENTERED NEAR NORTHWEST
SOUTH DAKOTA WITH AN EAST WEST WARM FRONTAL BOUNDARY EXTENDED
ACROSS NORTH CENTRAL SOUTH DAKOTA. FLOW OVER THE WARM FRONT WAS
GENERATING SHOWERS AND SCATTERED THUNDERSTORMS FROM MOBRIDGE NORTH
TO NEAR MINOT AND NORTH TO THE CANADIAN BORDER.
CONCERNING SEVERE WEATHER POTENTIAL...AN 18Z KBIS SOUNDINGS WAS
CONDUCTED. HRRR FORECAST CAPE VALUES IN THE NEIGHBORHOOD OF 2000
ARE FORECAST TO POOL ACROSS SOUTH CENTRAL INTO SOUTHEAST NORTH
DAKOTA LATE THIS AFTERNOON AND EVENING. EXPECT THE SEVERE WEATHER
POTENTIAL TO EXTEND FROM BISMARCK EAST. TO THE WEST EXPECT MORE
ELEVATED THUNDERSTORMS.
LATE TONIGHT AND SUNDAY...AN UPPER LEVEL LOW SWINGS INTO EASTERN
SOUTH DAKOTA THEN TRACKS NORTHEAST AND SPREADS A LARGE AREA OF THE
RAINSHOWERS ACROSS THE EAST HALF OF THE STATE AND ESPECIALLY THE
JAMES RIVER VALLEY. ACROSS THE NORTH CENTRAL...COOLER AIR WILL
BEGIN A RAIN/SNOW CHANGE OVER. AS THE SURFACE LOW WRAPS UP NORTH
WINDS OF 25 TO 35 MPH WILL BE COMMON ACROSS CENTRAL NORTH DAKOTA
ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM CDT SAT MAY 16 2015
RAIN...SNOW AND COLD TEMPERATURES WILL HIGHLIGHT THE LONG TERM.
THE STORM IMPACTING NORTH DAKOTA SATURDAY AND SUNDAY WILL CONTINUE
TO INFLUENCE THE REGION THROUGH MONDAY. THE UPPER LEVEL LOW AND
SURFACE LOW WILL BECOME NEARLY VERTICALLY STACKED OVER EASTERN
NORTH DAKOTA SUNDAY NIGHT. THIS WILL LEAD TO ENHANCED LIFT AND
PRECIPITATION ACROSS PORTIONS OF CENTRAL AND EASTERN NORTH DAKOTA.
AS THE LOW PROPAGATES EASTWARD SUNDAY NIGHT INTO MONDAY...COLD
AIR WILL WRAP IN FROM THE NORTH. A STEADY RAIN WILL TRANSITION TO
SNOW FROM NORTHWEST TO SOUTHEAST SUNDAY NIGHT. IN ADDITION TO
TRANSITIONING RAIN TO SNOW...STRONG COLD AIR ADVECTION AND A STEEP
PRESSURE GRADIENT WILL PRODUCE GUSTY NORTHWEST WINDS AROUND 35
MPH.
THE 12 UTC GFS/ECMWF/SREF/GEM ARE IN GOOD AGREEMENT WITH RESPECT
TO PRECIPITATION AMOUNTS AND TEMPERATURES. THEREFORE...UTILIZED A
BLEND OF THE OPERATIONAL MODELS. THIS GENERALLY YIELDED LIQUID
PRECIPITATION AMOUNTS AROUND HALF AN INCH AND SNOW AMOUNTS AROUND
1 OR 2 INCHES SUNDAY NIGHT INTO MONDAY. WITH TEMPERATURES HOVERING
NEAR FREEZING...ROAD TEMPERATURES COULD BE WARM ENOUGH TO LIMIT
NEGATIVE IMPACTS TO TRAVEL. FROST AND TEMPERATURES IN THE 20S AND
LOW 30S ARE LIKELY SUNDAY NIGHT AND MONDAY NIGHT.
FOR NORTH DAKOTA THE REST OF THE LONG TERM APPEARS COOL AND
DRY...WITH FREQUENT RAIN CHANCES ACROSS SOUTH DAKOTA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 117 AM CDT SUN MAY 17 2015
MVFR AND IFR CONDITIONS IN RAIN THROUGH MUCH OF THE TAF PERIOD.
NORTHERLY WINDS AT KISN/KMOT/KDIK/KBIS WILL INCREASE DURING THE
MORNING. WINDS AT KJMS SHOULD BECOME NORTHERLY BY AROUND DAYBREAK
AND INCREASE THROUGH THE MORNING.
&&
.HYDROLOGY...
ISSUED AT 340 PM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND TWO INCHES. CONFIDENCE IS LOW REGARDING TIMING AND
PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING
EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN
AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...AJ
AVIATION...JV
HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1123 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1122 PM CDT SAT MAY 16 2015
FORECAST CHALLENGE FOR REMAINDER OF THE NIGHT WILL BE TRENDS ON
DECREASING SHOWERS AND ISOLATED TSTMS AS THE FIRST WAVE OF PRECIP
IN THE WEST MOVES INTO SOUTHERN CANADA AND SHOWERS IN THE EAST
MOVE INTO NE MINNESOTA. THE HRRR HAS BEEN USEFUL FOR 3 TO 6 HOURS
OUT TONIGHT...AND WILL CONTINUE USING ITS POP TRENDS FOR GUIDANCE.
THERE IS A PRECIP FREE AREA MAINLY ACROSS WITHIN THE RED RIVER
VALLEY AND ADJACENT COUNTIES...WITH MOST PRECIP OVER DVL BASIN AND
FORESTED AREAS OF MN. WILL SEE A GRADUAL DISSIPATION OVERNIGHT
WITH ANOTHER WAVE OF PRECIP FORMING OVER CNTRL PLAINS NEAR MORNING
AND SPREADING NORTHWARD BY MID MORNING AND THROUGHOUT THE
AFTERNOON. WILL KEEP SCT SHOWERS/ISOLD TSTMS OVERNIGHT TONIGHT
ACROSS THE REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 320 PM CDT SAT MAY 16 2015
FORECAST CHALLENGE FOR TONIGHT IS SEVERE POTENTIAL. CLOUDS HAVE
PLAYED INTO THIS A BIT FOR OUR FA TODAY...PROBABLY MOST FOR THE
NORTHERN HALF OF THE AREA. AS OF 20Z THE BROAD SFC LOW WAS LOCATED
SOMEWHERE OVER WESTERN SD. THE WARM FRONT EXTENDED OUT TO THE EAST
INTO NORTHEAST SD AND SOUTHERN MN. SEEING SOUTH WINDS BEHIND THE
FRONT AND MORE SOUTHEAST THEN ESE UP INTO THE SOUTHERN FA. TEMPS
BEHIND THE FRONT IN THE MID 70S WITH DEW POINTS IN THE LOWER 60S.
THIS IS GIVING SFC BASED CAPE VALUES OF 1000 J/KG UP INTO SOUTH
CENTRAL ND. MUCH HIGHER VALUES OVER EAST CENTRAL SD. NOT THE
GREATEST AMOUNT OF SHEAR...BUT ALSO BETTER SOUTH OF THE FA.
RECEIVED A SWOMCD AT 210 PM DISCUSSING THE POTENTIAL FOR SEVERE
WEATHER UP INTO OUR FAR SOUTHERN FA. IF ORGANIZED CONVECTION CAN
GET GOING HERE THIS WOULD BE THE FAVORED AREA FOR A WATCH. THINK
THE BEST POTENTIAL WILL STILL BE IN THE 4-5 PM THROUGH MID EVENING
TIME FRAME DOWN IN THIS AREA. THUNDERSTORMS SHOULD DECREASE IN
INTENSITY OVERNIGHT...BUT AS THE STRONGER DYNAMICS APPROACH ON
SUNDAY THERE SHOULD COULD BE ANOTHER CHANCE OF SEVERE WEATHER.
THIS TIME ACROSS THE SOUTHEAST FA AS THE LOW LEVEL AND UPPER JET
PUNCH INTO THIS AREA AHEAD OF THE SHORT WAVE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 PM CDT SAT MAY 16 2015
TEMPS FALL AND WINDS CRANK UP ACROSS THE NORTHWEST FA SUNDAY
NIGHT. COULD BE A LITTLE LIGHT SNOW ACROSS THIS AREA...CURRENTLY
SHOWING THE POTENTIAL FOR 1-3 INCHES FROM LANGDON TO KDVL. STILL
WINDY INTO MONDAY WITH SOME LINGERING LIGHT SNOW ACROSS PORTIONS
OF THE NORTHERN FA. FINALLY SEE PCPN MOVING EAST MON NIGHT INTO
TUE.
BEYOND...FOR THE LATER HALF OF THE WEEK INTO THE FIRST PART OF
THE WEEKEND HIGH PRESSURE DOES SITUATE ITSELF ALONG THE NORTH
DAKOTA/MANITOBA AND SASKATCHEWAN BORDERS. THIS WILL BRING SOME
WELCOME DRY WEATHER TO OUR AREA MID TO LATE WEEK. THERE IS A
SYSTEM MOVING INTO THE WEST COAST AND INTO THE CENTRAL PLAINS FRI-
SAT AND THE NORTHERN EDGE OF MOISTURE FROM THIS SYSTEM MAY BRUSH
SOUTHERN ND AND WEST CENTRAL MINNESOTA. 00Z ECMWF WAS MORE
AGGRESSIVE WITH PRECIP THAN ITS 12Z RUN. 12Z ECMWF RUN FOLLOWS
DRIER 00Z AND 12Z GFS RUNS. BUT KEPT IDEA OF LOW POPS IN THE
SOUTHERN FCST AREA DUE TO UNCERTAINTY WITH NORTHERN EDGE OF
MOISTURE. TEMPERATURES WARMING A BIT BACK CLOSER TO NORMAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1122 PM CDT SAT MAY 16 2015
SHOWERS AND TSTMS WILL MOVE OUT OF DVL AND BJI AREAS BY 07Z TO
08Z TIMEFRAME AND THE ENTIRE AREA SHOULD SEE A BREAK OVERNIGHT.
THE NEXT WAVE OF MAINLY SHOWERS WITH SOME EMBEDDED TSTMS WILL
ENTER SOUTHERN VALLEY NEAR SUNRISE AND SPREAD NORTH THROUGH THE
DAY...WITH WIDESPREAD COVERAGE TOMORROW AFTN. EXPECT PREDOMINANT
CIG TO BE LOWER MVFR RANGE WITH SOME DIPS INTO IFR THROUGH THE
DAY. THE DVL SHOULD RECEIVE THE WORSE CONDS AS THE RAIN WILL BE
ACCOMPANIED BY WIND GUSTS UP TO 50 MPH BY LATE TOMORROW AFTN INTO
THE EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...GODON
LONG TERM...GODON/RIDDLE
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
455 AM EDT SUN MAY 17 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST OVER THE SOUTHEAST EARLY
THIS WEEK. A COLD FRONT WILL APPROACH LATE MONDAY AND MOVE THROUGH
ON TUESDAY...BRINGING PRECIPITATION CHANCES TO BOTH THE MOUNTAINS
AND PIEDMONT. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL RETURN
WEDNESDAY. SOMEWHAT UNSETTLED WEATHER WILL RETURN LATE IN THE WEEK
WITH A STATIONARY FRONT SETTING UP OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 445 AM EDT...HOURLY TEMPERATURE TRENDS WERE ADJUSTED EARLY
THIS MORNING FOR SFC TEMPS COOLING A BIT MORE SLOWLY THAN GUIDANCE
GIVEN THE PASSING MID AND HIGH LEVEL CLOUD COVER.
OTHERWISE...THE HIGHLY AMPLIFIED UPPER FLOW PATTERN OVER THE CONUS
WILL KEEP A RIDGE IN PLACE OVER THE SE THROUGH THE NEAR TERM. PLENTY
OF MID AND HIGH DEBRIS CLOUDS WILL RIDE OVER THE RIDGE AXIS ACROSS
THE AREA...BUT WITH ENOUGH BREAKS TO PERMIT MAX TEMPS TO CLIMB TO
ABOUT 5 DEGREES ABOVE CLIMO IN MOST AREAS...AND TO FOSTER A HEALTHY
CUMULUS FIELD. THE NUMERICAL MODELS KEEP THE DEEPEST MOISTURE AND
BEST FORCING FROM S TO SW UPSLOPE FLOW AND LOW LEVEL WIND
CONVERGENCE CONFINED TO THE SPINE OF THE SOUTHERN APPALACHIANS THIS
AFTERNOON AND EVENING. REGIONAL RADARS ALREADY HAVE WEAK CONVECTION
ALONG THE AL/GA BORDER IN LOW LEVEL CONVERGENCE EARLY THIS
MORNING...AND ISOLD SHOWER ACTIVITY COULD REACH THE FAR SW MTNS
AROUND DAYBREAK. WRN MTN INSTABILITY WILL THEN INCREASE THROUGH THE
DAY...WITH SBCAPE VALUES RUNNING 2000 J/KG OR GREATER BY LATE
AFTERNOON NEAR THE TN BORDER. NAM AND RAP PROFILES HAVE MUCH MORE
LIMITED INSTABILITY EAST OF THE MOUNTAINS...AND THE NAM QPF
PRESENTATION OF MAINLY MTN COVERAGE FOR LATE DAY IS PREFERRED. WILL
THUS FEATURE LIKELY POPS THIS AFTN NEAR THE TN BORDER AND TAPER DOWN
TO BELOW SLIGHT CHANCE FOR CLT METRO.
CONVECTIVE COVERAGE SHOULD WANE QUICKLY THIS EVENING...BUT WILL KEEP
ISOLD SHOWER COVERAGE GOING THROUGH THE NIGHT IN DEVELOPING LIGHT
WESTERLY UPSLOPE FLOW. MILD MINS SHOULD BE ANOTHER 1 TO 2 DEGREES
WARMER THAN THIS MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...UPPER HEIGHTS WILL FALL MONDAY OVER THE NERN
CONUS AS LOW PRESSURE MOVES ACRS THE GREAT LAKES. LATEST MODEL PROGS
SHOW LITTLE IMPACT IN THE HEIGHT FIELD OVER THE SOUTHEAST...BUT STILL
SHOW LLVL FLOW VEERING TO NWLY AS THE DAY PROGRESSES. WITHOUT GULF
FLOW ENHANCING WARM/MOIST ADVECTION THE THERMODYNAMIC CONDITIONS WILL
LIKELY BE SIMILAR TO SUNDAY...EXCEPT THAT THE WEAKER RIDGE WILL ALLOW
DEEP CONVECTION OVER THE PIEDMONT AS WELL AS OVER THE MTNS. DEEP
SHEAR REMAINS SMALL. SEVERE DOWNBURST WINDS CANNOT BE TOTALLY RULED
OUT BUT WILL LIKELY REMAIN ISOLATED. PWAT VALUES WELL ABOVE CLIMO AND
SHORT STORM MOTION VECTORS IMPLY HEAVY RAIN WILL BE A MORE LIKELY
THREAT.
AS THE LOW MOVES EWD INTO QUEBEC MON NIGHT...ITS COLD FRONT WILL
CROSS THE SRN APPALACHIANS. EAST OF THE MTNS CONVECTION SHOULD
GRADUALLY WANE WITH THE LOSS OF DIURNAL HEATING...BUT STRENGTHENING
UPSLOPE FLOW MAY ALLOW ACTIVITY TO CONTINUE OVERNIGHT NEAR THE TENN
BORDER. LATER ON TUE THE FRONT WILL PROGRESS ACRS THE CWFA. OVER THE
HIGHER TERRAIN SLIGHTLY COOLER TEMPS AND AN EARLIER THAN NORMAL PEAK
IN CONVECTIVE ACTIVITY ARE EXPECTED. THE PIEDMONT HOWEVER LOOKS TO
SEE A DAY VERY MUCH LIKE MONDAY...PERHAPS EVEN WITH BETTER COVERAGE
DUE TO FRONTAL CONVERGENCE OR MTN LEE TROUGHING. THE THREATS WILL BE
GENERALLY THE SAME.
MAX TEMPS MON/TUE WILL BE AROUND 5 DEG ABOVE CLIMO IN THE MTNS AND
NEAR 10 ABOVE IN THE PIEDMONT. CLOUD COVER WILL HELP KEEP MINS 7-10
DEG ABOVE CLIMO THROUGHOUT THE AREA...BUT TREND COOLER FROM TUE TO
WED MRNG AS THE CANADIAN AIRMASS SETTLES IN.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...HIGH PRESSURE BUILDS INTO THE OH/TN VALLEYS WED
PUSHING THE COLD FRONT THRU OUR AREA...WHICH THEN STALLS. GFS AND EC
HAVE PREVIOUSLY DIFFERED ON WHETHER THE FRONT WOULD CLEAR THE AREA
BEFORE BECOMING STATIONARY...BUT HAVE COME CLOSER IN LINE AND SUGGEST
IT WILL DO SO NEAR OUR SRN CWFA BORDER. WITH A TROUGH PERSISTING OVER
ERN CANADA....CYCLONIC UPPER FLOW WILL BE PRESENT ALOFT OVER THE CWFA
POTENTIALLY ENHANCING ANY BAROCLINIC FORCING ASSOCIATED WITH THE
BOUNDARY. A CUTOFF UPPER LOW MOVING IN FROM THE PACIFIC WILL SPIN UP
A NEW LOW OVER THE ROCKIES SATURDAY...LIFTING THE STATIONARY FRONT
NWD AGAIN. LOW CHANCES OF PRECIP RETURN THU AND PERIODICALLY CONTINUE
THRU THE WEEKEND...WITH LOW CONFIDENCE IN LIGHT OF MODEL DIFFERENCES
IN TIMING THE UPPER FEATURES WHICH INTERACT WITH THE BOUNDARY...AND
IN THE PLACEMENT OF THE BOUNDARY ITSELF...SINCE AREAS ON ITS WARM
SIDE ARE LIKELY TO SEE SOME DIURNAL CONVECTION. TEMPS COOL SLIGHTLY
BY THU...REMAINING JUST ABOVE CLIMO FOR MINS/MAXES THRU THE END OF
THE PERIOD.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
AT KCLT...EXPECT MAINLY CIRRUS CEILINGS THROUGH MOST OF THE
PERIOD...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING ONCE AGAIN
AROUND 5 KFT WITH DAYTIME HEATING. THE MODEL PROFILES ARE ALSO
SUGGESTING THAT A BRIEF ROUND OF LOWER STRATUS COULD DEVELOP TOWARD
DAYBREAK...BUT THIS IS LARGELY ABSENT FROM THE MOS GUIDANCE. WILL
THUS FEATURE ONLY A SCATTERED MVFR LEVEL LOWER CLOUD LAYER CIRCA 11Z
TO 13Z. WARM TEMPERATURES ALOFT UNDER THE RIDGE WILL LIMIT
INSTABILITY AND LITTLE IN THE WAY OF CONVECTIVE TRIGGERS WILL BE
FOUND EAST OF THE MTNS THIS AFTN/EVENING. EXPECT LIGHT S TO SW WINDS
THROUGHOUT AT LESS THAN 10 KT.
ELSEWHERE...MAINLY ALTOCUMULUS AND CIRRUS CEILINGS ARE EXPECTED THIS
MORNING...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING WITH HEATING
TO PRODUCE SOME VFR CIGS AT 4 TO 5 KFT THROUGH THE DAY. THE DEEPER
MOISTURE AND BEST FORCING FROM UPSLOPE AND LOW LEVEL WIND
CONVERGENCE WILL BE FOUND OVER THE WRN MTNS AND ALONG THE RIDGE TOPS
TODAY...WITH KAVL STANDING THE BEST CHANCE OF AN AFTN/EVENING TSRA.
WILL FEATURE VCSH WITH AFTN PROB30 TSRA AT KAVL...AND PROB30 TSRA AT
KHKY...BUT KEEP THE UPSTATE TAF SITES DRY WITH MORE LIMITED
INSTABILITY EXPECTED IN THE PROFILES. WINDS WILL BE LIGHT S TO SW
THROUGHOUT AT 10 KT OR LESS THROUGH THE PERIOD.
OUTLOOK...DEEPER MOISTURE WILL ARRIVE IN THE APPALACHIANS MON
THROUGH TUE AS A COLD FRONT APPROACHES FROM THE W. THE FRONT WILL
SETTLE SOUTHEAST OF THE AREA ON WEDNESDAY TO PERMIT BRIEF DRYING MID
WEEK. UNTIL THEN...DIURNAL SHOWERS AND THUNDERSTORMS WILL
FORM...WITH THE BEST COVERAGE OVER THE MTNS...WITH MORNING FOG
LIKELY IN AREAS THAT RECEIVE RAINFALL.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
312 AM EDT SUN MAY 17 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST OVER THE SOUTHEAST EARLY
THIS WEEK. A COLD FRONT WILL APPROACH LATE MONDAY AND MOVE THROUGH
ON TUESDAY...BRINGING PRECIPITATION CHANCES TO BOTH THE MOUNTAINS
AND PIEDMONT. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL RETURN
WEDNESDAY. SOMEWHAT UNSETTLED WEATHER WILL RETURN LATE IN THE WEEK
WITH A STATIONARY FRONT SETTING UP OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM EDT...THE HIGHLY AMPLIFIED UPPER FLOW PATTERN OVER THE
CONUS WILL KEEP A RIDGE IN PLACE OVER THE SE THROUGH THE NEAR TERM.
PLENTY OF MID AND HIGH DEBRIS CLOUDS WILL RIDE OVER THE RIDGE AXIS
ACROSS THE AREA...BUT WITH ENOUGH BREAKS TO PERMIT MAX TEMPS TO
CLIMB TO ABOUT 5 DEGREES ABOVE CLIMO IN MOST AREAS...AND TO FOSTER A
HEALTHY CUMULUS FIELD. THE NUMERICAL MODELS KEEP THE DEEPEST
MOISTURE AND BEST FORCING FROM S TO SW UPSLOPE FLOW AND LOW LEVEL
WIND CONVERGENCE CONFINED TO THE SPINE OF THE SOUTHERN APPALACHIANS
THIS AFTERNOON AND EVENING. REGIONAL RADARS ALREADY HAVE WEAK
CONVECTION ALONG THE AL/GA BORDER IN LOW LEVEL CONVERGENCE EARLY
THIS MORNING...AND ISOLD SHOWER ACTIVITY COULD REACH THE FAR SW MTNS
AROUND DAYBREAK. WRN MTN INSTABILITY WILL THEN INCREASE THROUGH THE
DAY...WITH SBCAPE VALUES RUNNING 2000 J/KG OR GREATER BY LATE
AFTERNOON NEAR THE TN BORDER. NAM AND RAP PROFILES HAVE MUCH MORE
LIMITED INSTABILITY EAST OF THE MOUNTAINS...AND THE NAM QPF
PRESENTATION OF MAINLY MTN COVERAGE FOR LATE DAY IS PREFERRED. WILL
THUS FEATURE LIKELY POPS THIS AFTN NEAR THE TN BORDER AND TAPER DOWN
TO BELOW SLIGHT CHANCE FOR CLT METRO.
CONVECTIVE COVERAGE SHOULD WANE QUICKLY THIS EVENING...BUT WILL KEEP
ISOLD SHOWER COVERAGE GOING THROUGH THE NIGHT IN DEVELOPING LIGHT
WESTERLY UPSLOPE FLOW. MILD MINS SHOULD BE ANOTHER 1 TO 2 DEGREES
WARMER THAN THIS MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...UPPER HEIGHTS WILL FALL MONDAY OVER THE NERN
CONUS AS LOW PRESSURE MOVES ACRS THE GREAT LAKES. LATEST MODEL PROGS
SHOW LITTLE IMPACT IN THE HEIGHT FIELD OVER THE SOUTHEAST...BUT STILL
SHOW LLVL FLOW VEERING TO NWLY AS THE DAY PROGRESSES. WITHOUT GULF
FLOW ENHANCING WARM/MOIST ADVECTION THE THERMODYNAMIC CONDITIONS WILL
LIKELY BE SIMILAR TO SUNDAY...EXCEPT THAT THE WEAKER RIDGE WILL ALLOW
DEEP CONVECTION OVER THE PIEDMONT AS WELL AS OVER THE MTNS. DEEP
SHEAR REMAINS SMALL. SEVERE DOWNBURST WINDS CANNOT BE TOTALLY RULED
OUT BUT WILL LIKELY REMAIN ISOLATED. PWAT VALUES WELL ABOVE CLIMO AND
SHORT STORM MOTION VECTORS IMPLY HEAVY RAIN WILL BE A MORE LIKELY
THREAT.
AS THE LOW MOVES EWD INTO QUEBEC MON NIGHT...ITS COLD FRONT WILL
CROSS THE SRN APPALACHIANS. EAST OF THE MTNS CONVECTION SHOULD
GRADUALLY WANE WITH THE LOSS OF DIURNAL HEATING...BUT STRENGTHENING
UPSLOPE FLOW MAY ALLOW ACTIVITY TO CONTINUE OVERNIGHT NEAR THE TENN
BORDER. LATER ON TUE THE FRONT WILL PROGRESS ACRS THE CWFA. OVER THE
HIGHER TERRAIN SLIGHTLY COOLER TEMPS AND AN EARLIER THAN NORMAL PEAK
IN CONVECTIVE ACTIVITY ARE EXPECTED. THE PIEDMONT HOWEVER LOOKS TO
SEE A DAY VERY MUCH LIKE MONDAY...PERHAPS EVEN WITH BETTER COVERAGE
DUE TO FRONTAL CONVERGENCE OR MTN LEE TROUGHING. THE THREATS WILL BE
GENERALLY THE SAME.
MAX TEMPS MON/TUE WILL BE AROUND 5 DEG ABOVE CLIMO IN THE MTNS AND
NEAR 10 ABOVE IN THE PIEDMONT. CLOUD COVER WILL HELP KEEP MINS 7-10
DEG ABOVE CLIMO THROUGHOUT THE AREA...BUT TREND COOLER FROM TUE TO
WED MRNG AS THE CANADIAN AIRMASS SETTLES IN.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...HIGH PRESSURE BUILDS INTO THE OH/TN VALLEYS WED
PUSHING THE COLD FRONT THRU OUR AREA...WHICH THEN STALLS. GFS AND EC
HAVE PREVIOUSLY DIFFERED ON WHETHER THE FRONT WOULD CLEAR THE AREA
BEFORE BECOMING STATIONARY...BUT HAVE COME CLOSER IN LINE AND SUGGEST
IT WILL DO SO NEAR OUR SRN CWFA BORDER. WITH A TROUGH PERSISTING OVER
ERN CANADA....CYCLONIC UPPER FLOW WILL BE PRESENT ALOFT OVER THE CWFA
POTENTIALLY ENHANCING ANY BAROCLINIC FORCING ASSOCIATED WITH THE
BOUNDARY. A CUTOFF UPPER LOW MOVING IN FROM THE PACIFIC WILL SPIN UP
A NEW LOW OVER THE ROCKIES SATURDAY...LIFTING THE STATIONARY FRONT
NWD AGAIN. LOW CHANCES OF PRECIP RETURN THU AND PERIODICALLY CONTINUE
THRU THE WEEKEND...WITH LOW CONFIDENCE IN LIGHT OF MODEL DIFFERENCES
IN TIMING THE UPPER FEATURES WHICH INTERACT WITH THE BOUNDARY...AND
IN THE PLACEMENT OF THE BOUNDARY ITSELF...SINCE AREAS ON ITS WARM
SIDE ARE LIKELY TO SEE SOME DIURNAL CONVECTION. TEMPS COOL SLIGHTLY
BY THU...REMAINING JUST ABOVE CLIMO FOR MINS/MAXES THRU THE END OF
THE PERIOD.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
AT KCLT...EXPECT MAINLY CIRRUS CEILINGS THROUGH MOST OF THE
PERIOD...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING ONCE AGAIN
AROUND 5 KFT WITH DAYTIME HEATING. THE MODEL PROFILES ARE ALSO
SUGGESTING THAT A BRIEF ROUND OF LOWER STRATUS COULD DEVELOP TOWARD
DAYBREAK...BUT THIS IS LARGELY ABSENT FROM THE MOS GUIDANCE. WILL
THUS FEATURE ONLY A SCATTERED MVFR LEVEL LOWER CLOUD LAYER CIRCA 11Z
TO 13Z. WARM TEMPERATURES ALOFT UNDER THE RIDGE WILL LIMIT
INSTABILITY AND LITTLE IN THE WAY OF CONVECTIVE TRIGGERS WILL BE
FOUND EAST OF THE MTNS THIS AFTN/EVENING. EXPECT LIGHT S TO SW WINDS
THROUGHOUT AT LESS THAN 10 KT.
ELSEWHERE...MAINLY ALTOCUMULUS AND CIRRUS CEILINGS ARE EXPECTED THIS
MORNING...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING WITH HEATING
TO PRODUCE SOME VFR CIGS AT 4 TO 5 KFT THROUGH THE DAY. THE DEEPER
MOISTURE AND BEST FORCING FROM UPSLOPE AND LOW LEVEL WIND
CONVERGENCE WILL BE FOUND OVER THE WRN MTNS AND ALONG THE RIDGE TOPS
TODAY...WITH KAVL STANDING THE BEST CHANCE OF AN AFTN/EVENING TSRA.
WILL FEATURE VCSH WITH AFTN PROB30 TSRA AT KAVL...AND PROB30 TSRA AT
KHKY...BUT KEEP THE UPSTATE TAF SITES DRY WITH MORE LIMITED
INSTABILITY EXPECTED IN THE PROFILES. WINDS WILL BE LIGHT S TO SW
THROUGHOUT AT 10 KT OR LESS THROUGH THE PERIOD.
OUTLOOK...DEEPER MOISTURE WILL ARRIVE IN THE APPALACHIANS MON
THROUGH TUE AS A COLD FRONT APPROACHES FROM THE W. THE FRONT WILL
SETTLE SOUTHEAST OF THE AREA ON WEDNESDAY TO PERMIT BRIEF DRYING MID
WEEK. UNTIL THEN...DIURNAL SHOWERS AND THUNDERSTORMS WILL
FORM...WITH THE BEST COVERAGE OVER THE MTNS...WITH MORNING FOG
LIKELY IN AREAS THAT RECEIVE RAINFALL.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 98% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
152 AM EDT SUN MAY 17 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND AND EARLY NEXT WEEK. INCREASING MOISTURE OVER THE WESTERN
EDGE OF THE HIGH WILL BRING PRECIPITATION CHANCES MAINLY TO THE
MOUNTAINS EACH DAY. A COLD FRONT WILL APPROACH THE WESTERN CAROLINAS
LATE MONDAY AND MOVE OVER THE AREA ON TUESDAY. SLIGHTLY COOLER AND
DRIER HIGH PRESSURE WILL RETURN WEDNESDAY IN THE WAKE OF THE FRONT
AND LINGER THROUGH AT LEAST THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 135 AM EDT...THE HIGHLY AMPLIFIED UPPER FLOW PATTERN OVER THE
CONUS WILL KEEP A RIDGE IN PLACE OVER THE SE THROUGH THE NEAR TERM.
PLENTY OF MID AND HIGH DEBRIS CLOUDS WILL RIDE OVER THE RIDGE AXIS
ACROSS THE AREA...BUT WITH ENOUGH BREAKS TO PERMIT MAX TEMPS TO
CLIMB TO ABOUT 5 DEGREES ABOVE CLIMO IN MOST AREAS...AND TO FOSTER A
HEALTHY CUMULUS FIELD. THE NUMERICAL MODELS KEEP THE DEEPEST
MOISTURE AND BEST FORCING FROM S TO SW UPSLOPE FLOW AND LOW LEVEL
WIND CONVERGENCE CONFINED TO THE SPINE OF THE SOUTHERN APPALACHIANS
THIS AFTERNOON AND EVENING. REGIONAL RADARS ALREADY HAVE WEAK
CONVECTION ALONG THE AL/GA BORDER IN LOW LEVEL CONVERGENCE EARLY
THIS MORNING...AND ISOLD SHOWER ACTIVITY COULD REACH THE FAR SW MTNS
AROUND DAYBREAK. WRN MTN INSTABILITY WILL THEN INCREASE THROUGH THE
DAY...WITH SBCAPE VALUES RUNNING 2000 J/KG OR GREATER BY LATE
AFTERNOON NEAR THE TN BORDER. NAM AND RAP PROFILES HAVE MUCH MORE
LIMITED INSTABILITY EAST OF THE MOUNTAINS...AND THE NAM QPF
PRESENTATION OF MAINLY MTN COVERAGE FOR LATE DAY IS PREFERRED. WILL
THUS FEATURE LIKELY POPS THIS AFTN NEAR THE TN BORDER AND TAPER DOWN
TO BELOW SLIGHT CHANCE FOR CLT METRO.
CONVECTIVE COVERAGE SHOULD WANE QUICKLY THIS EVENING...BUT WILL KEEP
ISOLD SHOWER COVERAGE GOING THROUGH THE NIGHT IN DEVELOPING LIGHT
WESTERLY UPSLOPE FLOW. MILD MINS SHOULD BE ANOTHER 1 TO 2 DEGREES
WARMER THAN THIS MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
AS OF 245 PM SAT...WE WILL LET THE EARLIER CONVECTION WANE THROUGH
THE EVENING AND INTO THE OVERNIGHT HOURS ACROSS THE NORTH CAROLINA
MOUNTAINS AND NORTHEAST GEORGIA...WITH LOSS OF HEATING AND ABSENCE
OF CONTINUED FORCING. SUBTLE UPSLOPE WEST COMPONENT MAY KEEP THOSE
WESTERN FACING SLOPES WITH THE LAST VESTIGAGES OF SHOWERS.
THE PERSISTENT UPPER LEVEL RIDGE (H5) WILL FLATTEN SOMEWHAT MONDAY
AND EDGE OFF TO THE EAST...WHILE SURFACE LEE TROFFING (OR HYBRID
LOOK OF A BACK DOOR COLD FRONT) SETTLES ACROSS THE WESTERN/CENTRAL
NORTH CAROLINA PIEDMONT. CAPE VALUES AND PRECIPITABLE WATER INDICES
ON THE RISE MONDAY...AS A RESULT MECHANICAL LIFTING IN THE MOUNTAINS
SHOULD HELP GENERATE POPS NEAR OR SLIGHTLY ABOVE GUIDE (IN THE
LIKELY CATEGORY). WHETHER THE AFOREMENTIONED SURFACE REFLECTION
CONTRIBUTES TO ANOTHER POP FOCUS IN OUR EASTERN FORECAST AREA (FA)
MONDAY AFTERNOON IS DEBATABLE...NEVERTHELESS THE ENTIRE REGION WILL
GRADUALLY BECOMING PRIMED FOR SCATTERED CONVECTION. CORFIDI VECTORS
ARE VERY MINIMAL THEREFORE LOCALLY HEAVY RAIN IS CERTAINLY SOMETHING
IN THE CARDS. TEMPERATURE GUIDE FROM NEARLY ALL SUITE OF MODELS...
AND H85 TEMPERATURE PROFILES...ALL SUGGEST KEEPING THE CURRENT VERY
WARM TEMPERATURES IN THE FORECAST.
WE WILL SLOWLY RAMP DOWN POPS MONDAY NIGHT...ALBEIT PROBABLY MORE
SLOWLY THAN THE FASTER GUIDE POP TRENDS. A JUICY AIRMASS...WEAK
PERTABATIONS IN THE UPPER LEVELS...AND SURFACE SIGNAL...ALL COMBINE
TO SUGGEST CAUTION.
HOW TUESDAY UNFOLDS COULD BE INTERESTING...THE COLD FRONT WHICH WILL
BE APPROACHING FROM THE WEST...CONTINUES TO SLOW...WHILE THE HYBRID
TYPE WIND SHIFT SETTLES EAST AND SOUTH. THE UPPER FLOW FLATTENS...
AND THEIR APPEARS TO BE A WAVE RACING TOWARD THE REGION DURING THE
DAY. SINCE THE FLOW WILL BECOME MORE WESTERLY TUESDAY...CONVERGENCE
MIGHT BE MINIMAL...ALTHOUGH CAPE AND INSTABILITY WILL BE POSTIVES
FOR THUNDERSTORMS. AT THE MOMENT WE PLAN ON RUNNING MEDIUM RANGE
POPS...AS I CAN SEE A COUPLE OF DIFFERENT SCENERIOS WHICH WOULD
FAVOR DIFFERENT PARTS OF THE CWA. WE HAVE KEPT THE TEMPERATURES ON
THE WARM SIDE OF GUIDE TUESDAY AS WELL...GIVEN OVERALL THERMAL
PROFILE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 2 PM EDT SATURDAY...THE MEDIUM RANGE FCST BEGINS AT 00Z ON
WEDNESDAY WITH A SOMEWHAT FLAT UPPER RIDGE OVER THE SE CONUS AND A
POTENT LOOKING UPPER SHORTWAVE/TROF MOVING OVER THE GREAT LAKES. AS
THE TROF MOVES EASTWARD AND TOWARDS NORTHERN NEW ENGLAND...THE RIDGE
REMAINS FAIRLY FLAT OVER THE SE REGION THRU THURS. THIS MOSTLY ZONAL
UPPER PATTERN IS EXPECTED TO PERSIST OVER OUR REGION THRU THE
REMAINDER OF THE PERIOD WITH A LONGWAVE UPPER TROF DIGGING DOWN OVER
EXTREME SE CANADA AND THEN NEW ENGLAND BY THE END OF PERIOD. AT THE
SFC...THE COLD FRONT THAT WAS EXPECTED TO MOVE OVER THE FCST AREA
EARLY TUES HAS BEEN TRENDING SLOWER OVER THE PAST FEW MODEL CYCLES.
NOW ITS LOOKING LIKE THE FRONT WILL MOVE THRU ABOUT 12 TO 18 HOURS
LATER ON TUES AND INTO EARLY WED. REGARDLESS...THE FRONT IS STILL
EXPECTED TO SE OF THE CWFA BY ROUGHLY 12Z ON WED WITH COOLER AND
DRIER CANADIAN HIGH PRESSURE IN ITS WAKE. THE HIGH IS EXPECTED TO
PERSIST OVER THE AREA INTO THURS WITH THE LOW LVL FLOW BECOMING MORE
WEAK VARIABLE ON FRI AND SAT. AS FOR THE SENSIBLE FCST...PRECIP
CHANCES TAPER OFF QUICKLY EARLY WED MORNING WITH VALUES LESS THAN
20% AFTER ABOUT 6Z. THE REST OF WED SHOULD BE DRY WITH THE REST OF
THE MEDIUM RANGE CHARACTERIZED BY DIURNALLY DRIVEN SLIGHT TO SOLID
CHANCES FOR SH AND TS EACH AFTERNOON/EVENING. AS IS TYPICAL WITH
SUMMERTIME CONVECTION AND ANY UPSLOPE WIND COMPONENT...THE BEST POPS
ARE EXPECTED OVER THE HIGHER TERRAIN. TEMPS WERE NOT CHANGED MUCH
FROM THE PREVIOUS FCST WITH TEMPS WELL ABOVE CLIMO EACH DAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT...EXPECT MAINLY CIRRUS CEILINGS THROUGH MOST OF THE
PERIOD...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING ONCE AGAIN
AROUND 5 KFT WITH DAYTIME HEATING. THE MODEL PROFILES ARE ALSO
SUGGESTING THAT A BRIEF ROUND OF LOWER STRATUS COULD DEVELOP TOWARD
DAYBREAK...BUT THIS IS LARGELY ABSENT FROM THE MOS GUIDANCE. WILL
THUS FEATURE ONLY A SCATTERED LOWER CLOUD LAYER CIRCA 11Z TO 13Z.
WARM TEMPERATURES ALOFT UNDER THE RIDGE WILL LIMIT INSTABILITY AND
LITTLE IN THE WAY OF CONVECTIVE TRIGGERS WILL BE FOUND EAST OF THE
MTNS THIS AFTN/EVENING. EXPECT LIGHT S TO SW WINDS THROUGHOUT AT
LESS THAN 10 KT.
ELSEWHERE...MAINLY ALTOCUMULUS AND CIRRUS CEILINGS ARE EXPECTED THIS
MORNING...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING WITH HEATING
TO PRODUCE SOME VFR CIGS AT 4 TO 5 KFT THROUGH THE DAY. THE DEEPER
MOISTURE AND BEST FORCING FROM UPSLOPE AND LOW LEVEL WIND
CONVERGENCE WILL BE FOUND OVER THE WRN MTNS AND ALONG THE RIDGE TOPS
TODAY...WITH KAVL STANDING THE BEST CHANCE OF AN AFTN/EVENING TSRA.
WILL FEATURE VCSH WITH PROB30 TSRA AT KAVL...AND PROB30 TSRA AT
KHKY...BUT KEEP THE UPSTATE TAF SITES DRY WITH MORE LIMITED
INSTABILITY EXPECTED IN THE PROFILES. WINDS WILL BE LIGHT S TO SW
THROUGHOUT AT 10 KT OR LESS THROUGH THE PERIOD.
OUTLOOK...DEEPER MOISTURE WILL ARRIVE IN THE APPALACHIANS MON
THROUGH TUE AS A COLD FRONT APPROACHES FROM THE W. THE FRONT WILL
SETTLE SOUTHEAST OF THE AREA ON WEDNESDAY TO PERMIT BRIEF DRYING MID
WEEK. UNTIL THEN...DIURNAL SHOWERS AND THUNDERSTORMS WILL
FORM...WITH THE BEST COVERAGE OVER THE MTNS...WITH MORNING FOG
LIKELY IN AREAS THAT RECEIVE RAINFALL.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 99% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...HG
SHORT TERM...TS
LONG TERM...JPT
AVIATION...HG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
350 AM CDT SUN MAY 17 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SUN MAY 17 2015
UPPER LOW CENTER CURRENTLY LIFTING NORTH NORTHEAST ACROSS NORTH
CENTRAL NEBRASKA WILL SLOWLY TRACK THROUGH THE FORECAST AREA TODAY.
TWO AREAS OF RAIN SHOWERS WITH EMBEDDED THUNDER ARE IMPACTING THE
AREA. THE FIRST BROAD BAND AHEAD OF THE LOW IS TRACKING NORTHWARD
ACROSS OUR EASTERN COUNTIES AHEAD OF THE SURFACE AND UPPER LOW. THE
SECOND AREA OF PRECIPITATION ON THE BACK SIDE OF THE LOW ACROSS
SOUTH CENTRAL INTO EAST CENTRAL SOUTH DAKOTA IS PIVOTING IN A
GENERAL NORTHERLY DIRECTION IN ASSOCIATION WITH MID LEVEL TROWALING.
PRECIPITATION IS EXPECTED TO PERSIST THROUGH THE MORNING ACROSS
THESE AREAS...WITH DRY SLOTTING LIMITING PRECIPITATION TO MORE
SCATTERED ACTIVITY NEAR THE I29 CORRIDOR. THE HRRR AND RUC HAVE A
DECENT HANDLE IN THE TRACK AND TIMING OF PRECIPITATION...SO FOLLOWED
THESE MODELS. AS THE LOW BEGINS PULLING AWAY TO THE NORTH THIS
AFTERNOON...MUCH OF REGION WILL BE IN THE DRY SLOT...WITH ONLY
SCATTERED SHOWERS DIMINISHING FROM SOUTH TO NORTH THROUGH EARLY
EVENING. SEVERE STORMS ARE NOT EXPECTED WITH ACTIVITY TODAY.
CLOUDY SKIES...RAINFALL... AND COOLER AIR WRAPPING BEHIND THE LOW
WILL KEEP TEMPERATURES IN CHECK THIS AFTERNOON. THE MID TO UPPER 60S
ARE EXPECTED WEST OF I29 WITH THE LOW TO MID 70S TO THE EAST WHERE
THE COOLER AIRMASS WILL BE DELAYED AND A BIT MORE SUNSHINE AND DRIER
WEATHER IS EXPECTED. WINDS WILL INCREASE THROUGH THE DAY AS THE
PRESSURE GRADIENT TIGHTENS AS THE LOW LIFTS NORTH OF THE AREA.
SUSTAINED WINDS WILL BE NEAR ADVISORY LEVEL MID TO LATE
AFTERNOON...BUT RIGHT NOW IT LOOKS LIKE THEY WILL REMAIN TOO LOW FOR
HEADLINES. SKIES WILL REMAIN PARTLY TO MOSTLY CLOUDY TONIGHT WITH
MUCH COLDER TEMPERATURES FILTERING INTO THE REGION. LOWS TONIGHT
WILL BE IN THE MID 30S TO MID 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN MAY 17 2015
WINDY AND COOL STILL LOOKS GOOD FOR MONDAY. THE UPPER LOW WILL BE
FAR ENOUGH NORTHEAST TO PROVIDE LITTLE OR NO DYNAMIC SUPPORT FOR
LIGHT SHOWERS...AND WHILE THERE COULD BE A FEW SPRINKLES WITH THE
LOW CLOUDS...WILL LEAVE OUT FOR NOW. THE LOW CLOUD COVER SHOULD
DOMINATE SKIES OVER THE NORTHEAST TO EAST CENTRAL PART OF THE
FORECAST AREA WITH LESSER CLOUD COVER TO THE SOUTHWEST. TEMPERATURES
WILL BE ON THE VERY CHILLY SIDE WITH HIGHS IN THE MID 40S NORTHEAST
TO THE MID 50S SOUTH.
CLEARING SKIES MONDAY NIGHT WITH HIGH PRESSURE RIDGING INTO THE AREA
AND THIS HIGH WILL ALSO BRING DECREASING WINDS. CHILLY TEMPERATURES
MAY DROP TO FROSTY OR FREEZY LEVELS AND WIND LOOK LIGHT ENOUGH BY
EARLY TUESDAY MORNING TO ALLOW FOR FROST EXCEPT IN PART OF SOUTHWEST
MINNESOTA SO AFTER COORDINATION WILL SO MENTION.
TUESDAY LOOKS FAIRLY SUNNY WITH SOME SLOW INCREASE IN CLOUDS
SOUTHWEST. THIS SLOW CLOUD INCREASE WILL CONTINUE FROM THE SOUTHWEST
TUESDAY NIGHT INTO WEDNESDAY AS AN EJECTED WAVE FROM PACIFIC COAST
TROUGH APPROACHES FROM THE SOUTHWEST. THIS WAVE WILL BE SUPPRESSED
TO SOME DEGREE BY A NORTHWESTERLY UPPER FLOW OVER THE WESTERN GREAT
LAKES. LIGHT RAIN LIKELY SPREADING INTO THE SOUTHWEST CORNER OF THE
AREA LATE TUESDAY NIGHT MAY NOT GET TOO FAR NORTHEAST IF THIS
SUPPRESSION IS STRONG ENOUGH. FOR NOW WILL KEEP SOME MENTION OF
LIGHT RAIN CHANCE WEDNESDAY OVER THE SOUTHWEST HALF OF THE AREA. DO
NOT EXPECT MUCH RAIN IN ANY EVENT AS THE SYSTEM WILL BE STEADILY
WEAKENING WHILE BEING SUPPRESSED BETWEEN THE NORTHWESTERLY FLOW AND A
MODEST SOUTHERN PLAINS RIDGE. TEMPERATURES WILL STILL BE COOL WITH
50S HIGHS TUESDAY AND WEDNESDAY.
THE DEPARTURE OF WHAT IS LEFT OF THE WEAK WAVE WILL ALLOW THE RIDGE
TO BUILD A LITTLE MORE INTO THE AREA AND BRING DRY WEATHER WITH
MODEST WARMING THURSDAY INTO FRIDAY. LATE FRIDAY AND SATURDAY WILL
BRING A CHANCE OF SHOWERS AND STORMS AS THE PACIFIC TROUGH
APPROACHES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1051 PM CDT SAT MAY 16 2015
THE LATEST HRRR AND NAM12 MODELS CONTINUE TO BE IN PRETTY GOOD
AGREEMENT IN BRINGING THE NEXT ROUND OF RAINFALL NORTHWARD LATE
TONIGHT...THEN CURLING THE PRECIPITATION WESTWARD TOWARD DAY BREAK
SUNDAY. THERE IS A LOT OF RAINFALL UPSTREAM IN EASTERN NEB AND
WESTERN KS...SO HAVE NO REASON TO DOUBT THIS SCENARIO YET SO
INCLUDED THE RAIN IN THE TAFS. THE BIGGEST QUESTION MARK IS THE
AMOUNT OF THUNDERSTORMS. THERE COULD BE ELEVATED STORMS EMBEDDED
IN THE RAIN...SO INCLUDED THE MENTION OF TSRA ONLY IN A TEMPO
GROUP FOR OUR THREE SITES. FURTHERMORE...THE HUMIDITY TIME
SECTIONS AND MODEL SOUNDINGS SHOW WIDESPREAD MVFR TO POSSIBLE
LOWER END IFR CONDITIONS TAKING OVER LATE TONIGHT AND SUNDAY
MORNING NORTH OF I 90 IMPACTING THE KHON TAF SITE. HEADING FURTHER
SOUTHWARD...THE CEILINGS WILL BE HIGHER WITH LESS RAINFALL ON
SUNDAY. THEREFORE AM LESS PESSIMISTIC WITH THE CEILINGS IN THE
KFSD AND KSUX TAF SITES.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1139 PM CDT SAT MAY 16 2015
.UPDATE...AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 900 PM CDT SAT MAY 16 2015/
DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES
INDICATE A COUPLE OF SHORTWAVE TROUGH LOCATED ACROSS THE LOWER
MISSISSIPPI VALLEY THIS EVENING. THE FIRST SHORTWAVE IS LOCATED
OVER WEST TENNESSEE AND THE SECOND SHORTWAVE LOCATED OVER
CENTRAL/SOUTHERN MISSISSIPPI THIS EVENING. OVERALL CONVECTIVE
ACTIVITY HAS BEEN DIMINISHING WITH THE LOSS OF DAYTIME
INSTABILITY AND WITH THESE SHORTWAVES MOVING AWAY FROM THE MID
SOUTH. LATEST HRRR/00Z WRF AGREE WITH SHOWERS AND THUNDERSTORMS
DIMINISHING WITH COVERAGE THROUGHOUT THE REMAINDER OF THE NIGHT.
WILL UPDATE POPS AND ALL OTHER ELEMENTS TO REFLECT CURRENT TRENDS.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
PREV DISCUSSION... /ISSUED 627 PM CDT SAT MAY 16 2015/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 311 PM CDT SAT MAY 16 2015/
POPCORN TYPE SHOWERS AND THUNDERSTORMS ARE OCCURRING ACROSS THE
MIDSOUTH AND SURROUNDING AREAS. LATEST HRRR SHOWS THIS ACTIVITY
CONTINUING THROUGH AROUND 7-8 PM. THEREAFTER...ACTIVITY WILL
DISSIPATE FROM THE LOSS OF DAYTIME HEATING. EXPECT THE REMAINDER
OF THE NIGHT TO BE TRANQUIL. WILL LEAVE 30 POPS IN CASE A STRAY
SHOWER OR THUNDERSTORM DEVELOPS. LOWS WILL BE IN THE MID TO UPPER
60S.
A SEVERE LINE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP
THIS EVENING ACROSS OKLAHOMA...KANSAS...AND TEXAS. MODELS HAVE
BEEN PRETTY CONSISTENT WITH BRINGING THE REMNANTS OF THIS LINE
INTO EASTERN ARKANSAS AROUND SUNRISE. STILL EXPECT THE LINE TO BE
IN THE DYING PHASES AS IT MOVES IN. THE LINE WILL FALL APART AS IT
REACHES THE MS RIVER DURING THE MORNING. HOWEVER...REDEVELOPMENT
ALONG LEFTOVER BOUNDARIES WILL BE POSSIBLE ALONG AND EAST OF THE
MISSISSIPPI RIVER FROM MID-MORNING ON SUNDAY INTO THE AFTERNOON
HOURS.
EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DIE OUT AGAIN BY 7PM
SUNDAY EVENING. NEW DEVELOPMENT MAY OCCUR ALONG AND WEST OF THE
MISSISSIPPI RIVER DURING THE LATE EVENING TO OVERNIGHT HOURS AS A
SHORTWAVE MOVES INTO THE REGION. THIS ACTIVITY WILL BLOSSOM OVER
THE CWA INTO MONDAY.
THE COLD FRONT IS STILL EXPECTED TO MOVE INTO THE AREA MONDAY
NIGHT INTO TUESDAY. SCATTERED CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL CONTINUE ALONG AND AHEAD OF THE FRONT.
THE ECMWF AND GFS DIFFER ON HOW2 FAR SOUTH THE FRONT WILL
PROGRESS. IF THE ECMWF IS CORRECT...TUESDAY NIGHT MAY BE THE ONLY
DRY PERIOD BEFORE THE FRONT MOVES BACK NORTH AS A WARM FRONT.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL OCCUR ALONG AND AHEAD
OF THE WARM FRONT. THE FRONT WILL RETURN SOUTHWARD AS A COLD FRONT
ON THURSDAY. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
LIKELY OCCUR ON THURSDAY.
HIGH PRESSURE WILL THEN BUILD INTO THE AREA ON FRIDAY.
&&
.AVIATION...06Z TAFS
QUIET OVERNIGHT WITH LOW CLOUDS DEVELOPING TOWARD MORNING.
GUIDANCE HAS CIGS AS LOW AS 500 FT...BUT THAT IS PROBABLY A BIT
PESSIMISTIC. WILL TEMPO MVFR CIGS FOR A FEW HOURS AROUND SUNRISE
AT MEM AND MKL...WITH PREVAILING MVFR CIGS AT JBR AND TUP.
SHORT RANGE GUIDANCE IS A BIT LESS BULLISH WITH REDEVELOPMENT
EARLY TOMORROW. WILL DELAY THE INTRODUCTION OF VCTS UNTIL MID TO
EARLY AFTERNOON AS A LINE OF STORMS IS EXPECTED TO APPROACH FROM
THE WEST. ANY EARLY DEVELOPMENT...OR DEVELOPMENT AHEAD OF THE LINE
CAN BE HANDLED WITH AMENDMENTS. TEMPORARY IFR OR LIFR VIS CAN BE
EXPECTED WITH ANY THUNDERSTORMS...BUT PREVAILING CONDITIONS SHOULD
REMAIN MVFR TO VFR.
SOUTH WINDS AROUND 10KTS TONIGHT...INCREASING TO 10-15KTS TOMORROW
WITH GUSTS TO 25KT. HIGHER GUSTS NEAR THUNDERSTORMS.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1159 PM CDT SAT MAY 16 2015
.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION...
&&
.AVIATION...
OVERALL TAFS LOOK ON TRACK WITH MVFR CIGS DEVELOPING ACROSS THE
AREA. MAY GET SOME IFR FOR KCLL/KUTS/KCXO. WINDS STILL HOLDING
AROUND 10KTS ACROSS THE AREA HOWEVER. MAIN CHANGE WAS TO PUT VCTS
BACK IN TAFS SINCE GETTING STORMS IN NW HILL COUNTRY. RECENT HRRR
SEEMS TO BE PICKING UP ON THIS ACTIVITY WELL AND BRINGS IT INTO SE
TX AS A SQUALL LINE DURING THE LATE MORNING. STORMS SHOULD BE
WEAKENING BUT ENOUGH TO MENTION VCTS IN TAFS AND THEN TWEAK FROM
THERE WITH 12Z UPDATE AS STORMS EVOLVE.
39
&&
.PREV DISCUSSION... /ISSUED 930 PM CDT SAT MAY 16 2015/
DISCUSSION...
THE 00Z CRP SOUNDING SHOWED A SMALL CAP DEVELOPING OVER SE TX.
THERE WERE ISOLATED SHOWERS MOVING INLAND JUST EAST OF CHAMBERS
AND LIBERTY COUNTIES AT 920 PM. EXPECT THESE TO CONTINUE MOVING
INLAND AND STAY MAINLY EAST OF THE FORECAST AREA.
THE STORMS THAT WERE LOCATED ALONG THE DRY LINE OUT IN WEST AND
NORTH TEXAS SHOULD CONTINUE TO MOVE EASTWARD THROUGHOUT THE NIGHT.
THE 01Z RAP13 AND HRRR PLUS THE 00Z NAM12 WERE ALL PUSHING THE
AREA OF STORMS INTO THE FAR NORTHWESTERN COUNTIES BY MID MORNING
SUNDAY.
LOWERED THE POPS OVER THE NORTHERN COUNTIES TO 20 PERCENT FOR
TONIGHT. ALSO ADDED THE MENTION OF LESS THAN 20 PERCENT CHANCE FOR
SHOWERS OVER THE FAR EASTERN PORTIONS OF CHAMBERS...LIBERTY... AND
POLK COUNTIES. OTHERWISE...THE CURRENT FORECAST IS ON TRACK.
40
PREV DISCUSSION... /ISSUED 656 PM CDT SAT MAY 16 2015/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION...
AVIATION...
SOUTHERLY WINDS SHOULD REMAIN AROUND 8-12KTS TONIGHT AND THEN
INCREASE AGAIN TOMORROW TO 10-15KTS WITH GUSTS ABOVE 20KTS. CIGS
SHOULD DROP TO MVFR FOR THE MORNING HOURS. KCLL/KUTS/KCXO MAY SEE
A FEW HOURS OF IFR CIGS IN THE MORNING LIKE THIS MORNING. WILL
NEED TO MONITOR CONVECTION COMING OUT OF C TX TO SEE IF IT WILL
IMPACT TERMINALS IN THE MORNING WITH OUTFLOW BOUNDARY POSSIBLY
BEING A FOCUS FOR CONVECTION IN THE AFTERNOON. FOR NOW WILL GO
WITH VCSH AS CAPPING WILL STILL BE STRONG AND DAY TIME HEATING MAY
NOT BE ENOUGH FOR STORMS TO INITIATE.
39
PREV DISCUSSION... /ISSUED 305 PM CDT SAT MAY 16 2015/
DISCUSSION...
DAYTIME HEATING IS WORKING THE MAGIC THIS AFTERNOON WITH SCATTERED
SHOWERS AND THUNDERSTORMS NORTH OF THE 59 CORRIDOR. STORMS HAVE
BEEN SMALL AND NOT VERY IMPRESSIVE WITH WIND GUSTS OF 25 KNOTS /
VIL 25-40G/KG /STORM MOTIONS OF 23 KNOTS AND RAINFALL RATES OF
25-.75"/HOUR THANKS TO FAIRLY QUICK MOTION. THOUGH THE INSTABILITY
DOES CONTINUE TO INCREASE THE AMDAR SOUNDINGS SHOW THAT WITH PEAK
HEATING CAPE VALUES LIMITED TO 2100-2700J/KG WITH LITTLE
DIRECTIONAL SHEAR. EXPECT THAT REDEVELOPMENT WILL OCCUR THROUGH
THE REMAINING AFTERNOON HOURS PROGRESSIVELY FURTHER NORTH...THEN
WANE DURING THE EARLY EVENING HOURS. A FEW MODELS HIGHLIGHT
DEVELOPMENT WELL DOWN THE DRYLINE IN WEST TEXAS BETWEEN MAF/SJT.
IF THIS OCCURS THEN WILL NEED TO KEEP AN EYE ON THE TAIL- DRAGGERS
AS THEY MAY GET CLOSE TO THE NW CWA AFTER MIDNIGHT. HEAVY RAIN
THREAT LOOKS LOW HERE BUT NORTHWEST OF THE AREA THE THREAT SHOULD
INCREASE WHERE STORMS LINE UP AND TRAIN AS LLJ INTENSIFIES WITH
STORMS GOING MUCH OF THE NIGHT LIKELY JUST TO OUR NORTHWEST.
OVERNIGHT EXPECT ST DECK TO RETURN THE AREA AND SSE FLOW TO
CONTINUE ALBEIT SOMEWHAT LESS FORCEFULLY INLAND SO TEMPERATURES
SHOULD FALL SLOWLY GIVEN THE CLOUD COVER/WINDS.
UPPER RIDGING WILL CONTINUE TO PLAY A LARGER PART IN OUR DAILY
RAIN CHANCES AS RIDGING BUILDS INTO THE AREA 588-590DM 500MB
HEIGHTS COVER MUCH OF THE REGION SUNDAY AND EARLY MONDAY. THIS
SHOULD LEAD TO WARMER CONDITIONS AND A LITTLE MORE CAPPING. THEN
LATE MONDAY AND TUESDAY RIDGE FLATTENS AND RAIN CHANCES SHOULD
INCREASE SLIGHTLY FOR THE NORTHERN HALF OF THE AREA AS STORM TRACK
SHIFTS SLIGHTLY FURTHER SOUTH AND EAST. HIGHEST RAIN CHANCE THIS
WEEK LOOK TO BE OVER THE NORTHEAST COUNTIES ON MONDAY AND TUESDAY
AFTERNOON. FRONTAL BOUNDARY SLIPS SOUTH INTO THE NORTHEAST
PORTIONS TX/NW LA AND THIS COULD BECOME A FOCUS FOR STORMS.
HEAVIER RAINS IN THESE NORTHERN AREAS A THREAT MONDAY AND TUESDAY.
WEDNESDAY THE RIDGING RETURNS AND RAIN CHANCES AGAIN TAPER OFF.
NEXT TROUGH DROPS INTO THE DESERT SW FRIDAY/SATURDAY WHICH MAY SET
THE STAGE FOR SLIGHTLY HIGHER RAIN CHANCES IN OUR WESTERN ZONES
BUT EXTENDED GUIDANCE SHOWING THE RIDGING OVER THE GULF POSSIBLY
EXERTING ENOUGH INFLUENCE TO LIMIT RAIN CHANCES OVER AT LEAST THE
SOUTHEASTERN HALF OF THE AREA.
TEMPERATURES SHOULD RUN 2 TO 4 DEGREES WARMER THAN NORMAL DURING
THE DAY AND 4 TO 9 DEGREES WARMER ON MINS WITH THE PERSISTENT
MOIST GULF RETURN.
45
MARINE...
AS A STRONG STORM SYSTEM DEEPENS OVER THE CENTRAL PLAINS...
A TIGHTENING PRESSURE GRADIENT WILL HELP KEEP ELEVATED WINDS
AND SEAS ACROSS OUR COASTAL WATERS THROUGH SUNDAY. CAUTION FLAGS
ARE IN EFFECT...AND ADVISORIES MIGHT BE NEEDED. WINDS AND SEAS
ARE STILL EXPECTED TO DECREASE BEGINNING ON MONDAY...AND MAINLY
MODERATE ONSHORE WINDS ARE ANTICIPATED FOR MUCH OF THE WEEK.
42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 87 74 87 72 / 20 30 20 30 20
HOUSTON (IAH) 77 88 75 88 73 / 20 20 20 30 10
GALVESTON (GLS) 78 85 79 85 76 / 10 20 20 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 AM CDT SUNDAY FOR
THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH SUNDAY EVENING FOR
THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA
SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
214 AM EDT SUN MAY 17 2015
.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL MAINTAIN A MOIST SOUTHERLY FLOW OF AIR
ACROSS THE REGION THROUGH MONDAY. A COLD FRONT WILL SLOWLY
APPROACH FROM THE WEST LATE MONDAY...MOVING THROUGH THE REGION
TUESDAY. COOLER...DRIER AIR WILL FILTER INTO THE REGION BY THE
MID PART OF NEXT WEEK BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 835 PM EDT SATURDAY...
MAIN CORRIDOR OF CONVECTION REMAINS ACROSS THE FAR WESTERN THIRD
THIS EVENING IN AN AXIS OF HIGHER CAPE UNDER A WEAK CONVERGENCE
AREA ALONG THE TAIL OF ANOTHER PASSING WEAK MID LEVEL WAVE.
EVENING RNK SOUNDING SHOWING THINGS QUITE SATURATED WITH MOIST
PWATS AND WEAK VEERING OVERTOP RATHER STRONG INSTABILITY. THUS
APPEARS AT LEAST SHALLOW CONVECTION MAY CONTINUE TO LINGER A BIT
LONGER WEST AS STILL SEEING NEW DEVELOPMENT OFF OUTFLOW BANDS.
THUS KEEPING LIKELY/HIGH CHANCE POPS GOING ESPCLY VA HIGHLANDS/SE
WEST VA UNTIL JUST BEFORE MIDNIGHT. LATEST HRRR ALSO SHOWS SOME
COVERAGE OUT TO THE BLUE RIDGE IN VIRGINIA WHERE INSTABILITY YET
TO BE WORKED OVER MUCH. THEREFORE LEAVING IN SOME CHANCE POPS
FARTHER EAST INTO THE EARLY MORNING HOURS BEFORE ENOUGH
COOLING...AND LESS UPPER SUPPORT FINALLY CAUSES SHRA TO FADE. OTRW
DEGREE OF DEBRIS CLOUDS MAKING THINGS A BIT TRICKY WITH FOG
COVERAGE OVERNIGHT AS SHOULD STILL SEE RATHER WIDESPREAD
FOG/STRATUS WEST WHERE HEAVY RAIN HAS OCCURRED. ELSEWHERE APPEARS
PATCHY COVERAGE OUTSIDE OF AREAS THAT HAVE SEEN THE HEAVY
DOWNPOURS...AND MOSTLY IN THE LOW SPOTS/VALLEYS PROVIDED A BIT OF
CLEARING LATER. SOUPY ENVIRONMENT WILL ONLY ALLOW FOR GRADUAL TEMP
FALLS OVERNIGHT WITH MOST SPOTS STAYING IN THE 60S EXCEPT FOR
PERHAPS A FEW 50S NW VALLEYS.
PREVIOUS DISCUSSION AS OF 303 PM EDT SATURDAY...
SUBTROPICAL RIDGE CONTINUES FROM THE SOUTHEAST STATES INTO THE MID-
ATLANTIC REGION THIS AFTERNOON INTO SUNDAY. A SOUTHERLY FLOW OF WARM
AND HUMID AIR COMBINING WITH INSTABILITY AND WEAK SHORTWAVES THIS
THIS AFTERNOON GENERATING SCATTERED SHOWERS AND THUNDERSTORMS. CAPES
THIS AFTERNOON VARY FROM 500 TO 1K J/KG...AND LIS AROUND MINUS 1 TO
MINUS 3...WITH INCREASED PWAT ABOUT AN INCH. INTERESTING TO NOTE
OFF THE 18Z SPC MESOANALYSIS OF A 800 DOWNDRAFT CAPE LOCATED TO
OUR NORTHEAST. AS INDICATED BY SWODY1...THE BETTER DYNAMIC AND
CHANCE FOR STRONGER TO SEVERE ARE LOCATED TO OUR NORTH AND WEST.
ONE CONCERN FOR THIS AFTERNOON INTO TONIGHT WILL BE THE POTENTIAL
FOR LOCALLY HEAVY RAINS WITH WEAK STEERING CURRENTS LEADING TO
SLOW MOVING THUNDERSTORMS...ESPECIALLY ACROSS ACROSS THE
MOUNTAINS. EXPECT MOST OF THE CONVECTION TO DIMINISH THIS EVENING
WITH THE LOSS OF SOLAR HEATING. CAN NOT COMPLETELY DRIER IT
OUT...BECAUSE THERE IS ANOTHER UPPER DISTURBANCE ROTATING ACROSS
THE REGION OVERNIGHT INTO SUNDAY MORNING. WITH LOW LEVEL MOISTURE
AND LIGHT WINDS ANTICIPATE THAT AREAS OF FOG WILL FORM OVERNIGHT
ESPECIALLY IN LOCATION THAT RECEIVE RAINFALL ON SATURDAY. LOW
TEMPERATURE OVERNIGHT WILL BE MILD WITH READINGS FROM THE UPPER
50S IN THE MOUNTAINS TO THE MID 60S IN THE PIEDMONT.
UPPER RIDGE WILL HOLD FAST THROUGH SUNDAY BUT GRADUALLY START TO
FLATTEN OUT AND SHIFT EAST AS SURFACE HIGH PRESSURE CENTERED OFF THE
MID ATLANTIC COAST SURFACE SINKS FURTHER TO THE SOUTH. THE DAY TWO
CONVECTION KEEPS US IN GENERAL THUNDERSTORMS SUNDAY WITH BEST
DYNAMICS REMAINING TO OUR WEST. THE OROGRAPHIC FORCING WILL SERVE AS
THE PRIMARY MECHANISM FOR DIURNAL CONVECTION...ALONG WITH OUTFLOW
BOUNDARY INTERACTIONS AND POSSIBLY SOME WEAK UPPER SHORT WAVE
ENERGY. HIGH TEMPERATURES ON SUNDAY WILL RANGE FROM THE LOWER 70S IN
THE MOUNTAINS TO THE UPPER 80S IN THE PIEDMONT.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
AS OF 300 PM EDT SATURDAY...
MODELS CONTINUE TO BE IN GOOD AGREEMENT DURING SHORT TERM PERIOD IN
MAINTAINING A SOUTHEASTERN UPPER RIDGE AMPLIFYING INTO THE
BLACKSBURG FORECAST AREA THROUGH MONDAY NIGHT BEFORE BEING GRADUALLY
FLATTENED BY A SHORT WAVE TROF EXPECTED TO MOVE EAST THROUGH THE
GREAT LAKES ON TUESDAY.
WITH THE UPPER RIDGE HOLDING UNTIL TUESDAY...SLOWLY INCREASING HEAT
AND HUMIDITY ON LIGHT SOUTHWESTERLY FLOW ALONG THE PERIPHERY OF THE
UPPER RIDGE WILL CONTINUE TO SUPPORT DEVELOPMENT OF MAINLY DIURNALLY-
DRIVEN SHOWERS AND THUNDERSTORMS...MOST NOTABLY IN THE MOUNTAINS
WHERE THETA-E VALUES WILL BE THE HIGHEST...AND WHERE LOCALIZED
FORCED ASCENT AND DIFFERENTIAL HEATING DUE TO OROGRAPHIC INFLUENCES
WILL BE MAXIMIZED TO PUNCH THROUGH WEAK MID-LEVEL CAPPING INVERSION.
FORECAST SOUNDINGS CONTINUE TO MAINTAIN RELATIVELY WARM TEMPERATURES
IN THE MID LEVELS OF THE ATMOSPHERE ALONG WITH WEAK SHEAR INTO
TUESDAY...SUCH THAT SEVERE WEATHER THREAT EVEN UP THROUGH FRONTAL
PASSAGE ON TUESDAY APPEARS TO BE EXTREMELY LIMITED. CORFIDI VECTORS
YIELD A SLOW...BUT SUFFICIENTLY PROGRESSIVE MOTION SUCH THAT UNLESS
TRAINING ALONG AN OUTFLOW BOUNDARY AND/OR ANCHORING ON A OROGRAPHIC
POINT OCCURS...FLASH FLOODING THREAT SHOULD ALSO REMAIN MINIMAL
DESPITE PRECIPITABLE WATER VALUES GRADUALLY CLIMBING UP TO AND
MAXING OUT IN THE 1.6 - 1.8 INCH RANGE SUNDAY INTO MONDAY.
PASSAGE OF SHORT WAVE TROF AND ATTENDANT COOL FRONT LATER TUESDAY
SHOULD SHOULD BRING AN END TO THREAT FOR SCATTERED SHOWERS/STORMS
BY/DURING TUESDAY EVENING AS COOL ADVECTION IN WEST...AND
DOWNSLOPING EAST OF THE BLUE RIDGE TAKES OVER...SETTING THE STAGE
FOR DRIER AND SLIGHTLY COOLER WEATHER LATER TUESDAY NIGHT INTO THE
FIRST PART OF THE LONGER TERM PERIOD.
TEMPERATURES THROUGH THE PERIOD WILL CONTINUE TO BE LARGELY GOVERNED
BY EXTENT OF CLOUD COVER AND INFLUENCE OF CONVECTIVE OUTFLOW
BOUNDARIES...BUT NOT EXPECTED TO BE THAT FAR OFF CLIMATOLOGICAL
NORMALS AREA-WIDE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 PM EDT SATURDAY...
SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTHWEST SHOULD MAINTAIN
DRY AND SLIGHTLY COOLER WEATHER FOR THE BLACKSBURG FORECAST AREA
WEDNESDAY INTO AT LEAST THURSDAY MORNING.
APPROACH OF YET ANOTHER SERIES OF NORTHERN STREAM IMPULSES EXPECTED
TO SUFFICIENTLY BUCKLE/BACK UPPER FLOW AGAIN IN THURSDAY/FRIDAY
TIMEFRAME TO SUPPORT THE DEVELOPMENT OF WIDELY SCATTERED SHOWERS OR
ISOLATED THUNDERSHOWERS...MAINLY ACROSS THE SOUTHWESTERN VA INTO THE
MOUNTAINS OF NW NC WHERE RETURN FLOW AND THETA-E WILL BE A BIT
HIGHER.
OTHERWISE...ANOTHER RETURN TO DRIER WEATHER LOOKS TO BE IN THE
OFFING BY NEXT SATURDAY AS PASSAGE OF NORTHERN STREAM WAVES
SUFFICIENTLY DEEPENS/REESTABLISHES UPPER TROF OVER NEW
ENGLAND...SUPPORTING SURFACE HIGH PRESSURE THAT WILL SLIDE SOUTHEAST
INTO NEW ENGLAND AND WEDGE SOUTHWESTWARD INTO THE MID ATLANTIC
STATES.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 200 AM EDT SUNDAY...
RADAR INDICATES ONLY A FEW LINGERING SHOWERS ACROSS THE AREA THIS
MORNING. OVERALL...SHOWER ACTIVITY THROUGH LATE MORNING WILL
REMAIN MINIMAL...HOWEVER EXPECT TO SEE LIGHT RETURNS PASS ACROSS
FROM TIME TO TIME. PATCHY FOG AND LOW CEILINGS WILL AGAIN BE THE
MORE SIGNIFICANT ISSUE OVERNIGHT...MORE SO ACROSS THE MOUNTAINS
AND ESPECIALLY IN AREAS WHICH RECEIVED SIGNIFICANT RAINFALL ON
SATURDAY. FOG WILL BURN OFF QUICKLY AFTER 9 AM WITH STRONG DAYTIME
HEATING...AND LOW CEILINGS WILL GRADUALLY LIFT AND TRANSITION TO
STRATOCU THROUGH THE REMAINDER OF THE MORNING.
FOR SUNDAY...LOOKING FOR ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS SIMILAR TO WHAT OCCURRED ON SATURDAY...WITH
CONVECTION DEVELOPING ALONG THE MOUNTAIN RIDGES BEGINNING AS EARLY
AS 17/16Z. SHOWERS AND THUNDERSTORMS WILL BECOME SCATTERED TO
NUMEROUS ACROSS THE MOUNTAINS DURING MID/LATE AFTERNOON...WITH
WESTERLY FLOW PUSHING SOME OF THIS ACTIVITY EAST ACROSS THE
PIEDMONT DURING LATE AFTERNOON INTO THE EVENING. STORMS WILL AGAIN
BE SLOW MOVING AND CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL FOR
PROLONGED PERIODS OF TIME. AS SUCH...LOOKING AT THE POTENTIAL OF
LOCALIZED MVFR/IFR CONDITIONS WITHIN THE HEAVIER RAINSHAFTS...
REDUCING VISIBILITIES TO A FEW HUNDRED FEET AT TIMES. CONVECTION
WILL START TO WANE TOWARD SUNSET WITH THE LOSS OF HEATING...BUT
EXPECT SHOWERS AND A FEW THUNDERSTORMS TO REMAIN ON THE RADAR AS
LATE AS 18/04Z.
MEDIUM TO HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS
DURING THE TAF PERIOD.
EXTENDED AVIATION DISCUSSION...
LATE NIGHT/EARLY MORNING FOG AND ASSOCIATED IFR-LIFR VSBYS/CIGS
ARE HIGHLY LIKELY SUNDAY NIGHT INTO MONDAY GIVEN THE SOUPY
ATMOSPHERE IN PLACE. LATE MONDAY INTO TUESDAY...A COLD FRONT MOVES
THROUGH. THUNDERSTORMS SHOULD BE MOST NUMEROUS IN COVERAGE AND
STRONGEST IN INTENSITY DURING THIS TIME FRAME FOR ALL
AREAS...ENDING FROM THE WEST DURING TUESDAY. LONGER PERIODS OF
MVFR CIGS/VSBYS APPEAR LIKELY MONDAY-TUESDAY. BEHIND THE COLD
FRONT...DRIER/COOLER CONDITIONS ARE EXPECTED WED-THU WITH MOSTLY
VFR CONDITIONS AS HIGH PRESSURE SLIDES IN FROM THE NW.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...JH/KK
SHORT TERM...WERT
LONG TERM...WERT
AVIATION...JH/NF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1038 AM EDT SUN MAY 17 2015
.SYNOPSIS...
A DISSIPATING FRONTAL BOUNDARY OR TROUGH WILL MOVE ACROSS THE
AREA THIS MORNING BEFORE WASHING OUT. A BACKDOOR COLD FRONT WILL
THEN DROP SOUTHWEST ACROSS NEW ENGLAND TONIGHT AND ACROSS THE AREA
BY DAYBREAK MONDAY. THE FRONT STALLS JUST SOUTHWEST OF THE REGION
ON MONDAY WITH HIGH PRESSURE BUILDING IN FROM THE NORTHEAST. THIS
FRONT WILL LIFT THROUGH AS A WARM FRONT TUESDAY MORNING...FOLLOWED
BY A COLD FRONTAL PASSAGE TUESDAY EVENING. HIGH PRESSURE IS THEN
IN CONTROL INTO NEXT WEEKEND...WITH THE EXCEPTION OF A WEAK COLD
FRONTAL PASSAGE ON FRIDAY
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SOME COMPETING FEATURES ALOFT...WITH RIDGING BUILDING IN FROM THE
WEST FROM 850-500 HPA...SO WILL HAVE SUBSIDENCE ASSOCIATED WITH
THAT. AT THE SAME TIME ALL HI-RES MODELS SHOW WEAK SHORTWAVE GOING
OVER THE TOP OF THE RIDGE AND PASSING THIS AFTERNOON. NOTING HAVE
WARMED FASTER THAN FORECAST...ESPECIALLY OVER WESTERN
ZONES...SHOULD HAVE A BIT MORE LOW LEVEL INSTABILITY TO WORK WITH
THAN PREVIOUSLY THOUGHT. ALSO BASED ON THIS HAVE TWEAKED HIGHS UP
A COUPLE DEGREES AT MOST LOCATIONS...GENERALLY CONSISTENT WITH A
BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES. EXPECT
HIGHS TO BE AROUND 10-15 DEGREES ABOVE NORMAL AS A RESULT.
BASED ON THIS AND HRRR HAVE INCREASED AREA WITH SLIGHT CHANCE POPS
THIS AFTERNOON TO COVER ENTIRE LOWER HUDSON VALLEY/NE NJ/NYC.
WHILE ANY SHRA...WITH VERY LOW CHANCE OF A TSTM...WILL BE OF THE
HIT AND MISS VARIETY...GIVEN LIGHT WINDS ALOFT WILL BE SLOW TO
MOVE...SO COULD PRODUCE LOCALLY HEAVY RAINFALL. ONCE AGAIN...FAR
MORE LIKELY FOR A MISS THAN A HIT ON A SHRA AT ANY GIVEN LOCATION
OVER THE LOWER HUDSON VALLEY/NE NJ/NYC THIS AFTERNOON.
A WEAK W/SW FLOW WILL GIVE WAY TO SEABREEZES THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
UPPER LEVEL RIDGE AXIS BUILDS EAST ACROSS NEW ENGLAND
TONIGHT...WHICH IN TURN STRENGTHENS HIGH PRESSURE OVER THE
CANADIAN MARITIMES AND SENDS A BACKDOOR COLD ACROSS THE AREA BY
DAYBREAK. THE FRONT WILL STALL JUST SOUTHWEST OF THE FORECAST
AREA ON MON. HOWEVER..DUE TO THE CLOSE PROXIMITY OF THE BOUNDARY
CAN NOT RULE OUT SHOWERS...PRIMARILY FROM NYC AND POINTS WEST.
CLOUDS MOVE IN BEHIND THE COLD FRONT LATE TONIGHT AS A MOIST E
FLOW DEVELOPS ACROSS THE REGION. SOME CLEARING IS POSSIBLE MON
AFTERNOON ACROSS EASTERN LONG ISLAND/SE CT...WITH A MOSTLY CLOUDY
SKY FURTHER WEST.
LOWS TONIGHT WILL REMAIN MILD WITH THE CLOUD COVER AND DEVELOPING
EAST FLOW...HOWEVER...FOR THOSE SAME REASONS WILL BE ABOUT 5
DEGREES BELOW NORMAL ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE
WEEK WITH ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING
AROUND THE BASE RESULTS IN AMPLIFICATION.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN
THE EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH
PRESSURE THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH
THE END OF THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER
ASSOCIATED WITH A WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI
AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
A COLD FRONT APPROACHES FROM THE NORTH TODAY...AND MOVES THROUGH
THE REGION LATE TONIGHT INTO MONDAY MORNING.
CONDITIONS CONTINUE TO SLOWLY IMPROVE WITH SOME LINGERING STRATUS
AT KISP/KHPN/KTEB THROUGH 16Z. A BRIEF PERIOD OF MVFR CIGS 015 TO
020 IS POSSIBLE OVER THE CITY TERMINALS THROUGH 16Z.
OTHERWISE...VFR IS EXPECTED AFTER 16Z AT ALL TERMINALS.
WITH LIGHT FLOW OVER THE AREA...WINDS HAVE VARIED. NNW-NNE WINDS
OVER CITY TERMINALS AND KHPN/KISP UNDER 10 KT WILL BECOME SW
AROUND 10 KT THIS AFTERNOON. COASTAL TERMINALS WILL BECOME SOUTH
DUE TO AFTERNOON SEA BREEZES.
WINDS DIMINISH TO 5 KT OR LESS AFT 02Z MONDAY.
FOG/STRATUS LIKELY AGAIN LATE TONIGHT THROUGH MONDAY MORNING.
.OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
.MONDAY...IFR OR LOWER IN FOG/STRATUS IN THE MORNING...THEN
PATCHY MVFR CIGS IN THE AFTERNOON. E-NE WINDS 10-15 KT.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
A BACKDOOR COLD FRONT APPROACHES THE WATERS FROM THE NORTH LATER
TODAY AND PASSES SOUTH OF THE WATERS MONDAY MORNING. THE PRESSURE
GRADIENT GRADUALLY TIGHTENS AS HIGH PRES BUILDS ALONG THE NEW
ENGLAND COAST AND A COLD FRONT APPROACHES FROM THE WEST. THAT
FRONT MOVES ACROSS THE WATERS LATE TUESDAY...AND THEN HIGH PRES
RETURNS FOR THE MIDDLE OF THE WEEK.
SUB-SMALL CRAFT ADVISORY CONDITIONS ON TAP THROUGH MONDAY...AND
THEN SCA CONDITIONS EXPECTED ON WEDNESDAY BEHIND THE DEPARTING
COLD FRONT.
&&
.HYDROLOGY...
GENERALLY LIGHT RAINFALL AMOUNTS ARE POSSIBLE IN ANY SHOWERS THE
NEXT COUPLE OF DAYS...MAINLY WEST OF NYC.
HOWEVER...ANY SHOWERS WHICH DO FORM THIS AFTERNOON WILL BE VERY
SLOW TO MOVE. IF ANY STRONGER CONVECTION WERE TO FORM OVER A
LOCATION...THERE WOULD BE THE POTENTIAL FOR THE PONDING OF WATER
ON ROADWAYS AND POSSIBLY MINOR POOR DRAINAGE FLOODING DEPENDING ON
THE EXACT DURATION AND STRENGTH OF ANY GIVEN SHOWER WHICH MIGHT
FORM.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DW
NEAR TERM...MALOIT/DW
SHORT TERM...DW
LONG TERM...24/DW
AVIATION...MPS/DS
MARINE...MALOIT/MPS
HYDROLOGY...DW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1008 AM EDT SUN MAY 17 2015
.SYNOPSIS...
A DISSIPATING FRONTAL BOUNDARY OR TROUGH WILL MOVE ACROSS THE
AREA THIS MORNING BEFORE WASHING OUT. A BACKDOOR COLD FRONT WILL
THEN DROP SOUTHWEST ACROSS NEW ENGLAND TONIGHT AND ACROSS THE AREA
BY DAYBREAK MONDAY. THE FRONT STALLS JUST SOUTHWEST OF THE REGION
ON MONDAY WITH HIGH PRESSURE BUILDING IN FROM THE NORTHEAST. THIS
FRONT WILL LIFT THROUGH AS A WARM FRONT TUESDAY MORNING...FOLLOWED
BY A COLD FRONTAL PASSAGE TUESDAY EVENING. HIGH PRESSURE IS THEN
IN CONTROL INTO NEXT WEEKEND...WITH THE EXCEPTION OF A WEAK COLD
FRONTAL PASSAGE ON FRIDAY
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SOME COMPETING FEATURES ALOFT...WITH RIDGING BUILDING IN FROM THE
WEST FROM 850-500 HPA...SO WILL HAVE SUBSIDENCE ASSOCIATED WITH
THAT. AT THE SAME TIME ALL HI-RES MODELS SHOW WEAK SHORTWAVE GOING
OVER THE TOP OF THE RIDGE AND PASSING THIS AFTERNOON. NOTING HAVE
WARMED FASTER THAN FORECAST...ESPECIALLY OVER WESTERN
ZONES...SHOULD HAVE A BIT MORE LOW LEVEL INSTABILITY TO WORK WITH
THAN PREVIOUSLY THOUGHT. ALSO BASED ON THIS HAVE TWEAKED HIGHS UP
A COUPLE DEGREES AT MOST LOCATIONS...GENERALLY CONSISTENT WITH A
BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES. EXPECT
HIGHS TO BE AROUND 10-15 DEGREES ABOVE NORMAL AS A RESULT.
BASED ON THIS AND HRRR HAVE INCREASED AREA WITH SLIGHT CHANCE POPS
THIS AFTERNOON TO COVER ENTIRE LOWER HUDSON VALLEY/NE NJ/NYC.
WHILE ANY SHRA...WITH VERY LOW CHANCE OF A TSTM...WILL BE OF THE
HIT AND MISS VARIETY...GIVEN LIGHT WINDS ALOFT WILL BE SLOW TO
MOVE...SO COULD PRODUCE LOCALLY HEAVY RAINFALL. ONCE AGAIN...FAR
MORE LIKELY FOR A MISS THAN A HIT ON A SHRA AT ANY GIVEN LOCATION
OVER THE LOWER HUDSON VALLEY/NE NJ/NYC THIS AFTERNOON.
A WEAK W/SW FLOW WILL GIVE WAY TO SEABREEZES THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
UPPER LEVEL RIDGE AXIS BUILDS EAST ACROSS NEW ENGLAND
TONIGHT...WHICH IN TURN STRENGTHENS HIGH PRESSURE OVER THE
CANADIAN MARITIMES AND SENDS A BACKDOOR COLD ACROSS THE AREA BY
DAYBREAK. THE FRONT WILL STALL JUST SOUTHWEST OF THE FORECAST
AREA ON MON. HOWEVER..DUE TO THE CLOSE PROXIMITY OF THE BOUNDARY
CAN NOT RULE OUT SHOWERS...PRIMARILY FROM NYC AND POINTS WEST.
CLOUDS MOVE IN BEHIND THE COLD FRONT LATE TONIGHT AS A MOIST E
FLOW DEVELOPS ACROSS THE REGION. SOME CLEARING IS POSSIBLE MON
AFTERNOON ACROSS EASTERN LONG ISLAND/SE CT...WITH A MOSTLY CLOUDY
SKY FURTHER WEST.
LOWS TONIGHT WILL REMAIN MILD WITH THE CLOUD COVER AND DEVELOPING
EAST FLOW...HOWEVER...FOR THOSE SAME REASONS WILL BE ABOUT 5
DEGREES BELOW NORMAL ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE
WEEK WITH ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING
AROUND THE BASE RESULTS IN AMPLIFICATION.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN
THE EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH
PRESSURE THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH
THE END OF THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER
ASSOCIATED WITH A WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI
AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH AND SINKS TO THE
SOUTH LATER TODAY...AND MOVES THROUGH THE REGION MONDAY MORNING.
FOG/STRATUS ACROSS THE AREA THROUGH 13-15Z. CONDITIONS LIFTING TO
MVFR...BUT ALSO SOME PATCHY IFR/LIFR CONDITIONS LINGER. VFR BY
15Z.
LIGHT/VRB WINDS THROUGH LATE MORNING...THEN GENERALLY SW WINDS
5-10 KT...BECOMING SOUTH AT COASTAL TERMINALS DUE TO AFTERNOON SEA
BREEZES.
WINDS DIMINISH TO 5 KT OR LESS AFT 02Z MONDAY.
FOG/STRATUS LIKELY AGAIN LATE TONIGHT THROUGH MONDAY MORNING.
.OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
.MONDAY...IFR OR LOWER IN FOG/STRATUS IN THE MORNING...THEN
PATCHY MVFR CIGS IN THE AFTERNOON. E-NE WINDS 10-15 KT.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
A BACKDOOR COLD FRONT APPROACHES THE WATERS FROM THE NORTH LATER
TODAY AND PASSES SOUTH OF THE WATERS MONDAY MORNING. THE PRESSURE
GRADIENT GRADUALLY TIGHTENS AS HIGH PRES BUILDS ALONG THE NEW
ENGLAND COAST AND A COLD FRONT APPROACHES FROM THE WEST. THAT
FRONT MOVES ACROSS THE WATERS LATE TUESDAY...AND THEN HIGH PRES
RETURNS FOR THE MIDDLE OF THE WEEK.
SUB-SMALL CRAFT ADVISORY CONDITIONS ON TAP THROUGH MONDAY...AND
THEN SCA CONDITIONS EXPECTED ON WEDNESDAY BEHIND THE DEPARTING
COLD FRONT.
&&
.HYDROLOGY...
GENERALLY LIGHT RAINFALL AMOUNTS ARE POSSIBLE IN ANY SHOWERS THE
NEXT COUPLE OF DAYS...MAINLY WEST OF NYC.
HOWEVER...ANY SHOWERS WHICH DO FORM THIS AFTERNOON WILL BE VERY
SLOW TO MOVE. IF ANY STRONGER CONVECTION WERE TO FORM OVER A
LOCATION...THERE WOULD BE THE POTENTIAL FOR THE PONDING OF WATER
ON ROADWAYS AND POSSIBLY MINOR POOR DRAINAGE FLOODING DEPENDING ON
THE EXACT DURATION AND STRENGTH OF ANY GIVEN SHOWER WHICH MIGHT
FORM.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DW
NEAR TERM...MALOIT/DW
SHORT TERM...DW
LONG TERM...24/DW
AVIATION...MPS
MARINE...MALOIT/MPS
HYDROLOGY...DW
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1049 AM EDT SUN MAY 17 2015
.SYNOPSIS...
A WEAK FRONT WILL REMAIN ACROSS THE REGION TODAY AND TONIGHT. WEAK
HIGH PRESSURE WILL BE ACROSS THE AREA MONDAY. A LOW PRESSURE SYSTEM
WILL MOVE ACROSS THE UPPER GREAT LAKES AND SOUTHERN CANADA BRINGING
ITS ATTACHED FRONTS TO OUR AREA MONDAY NIGHT THROUGH TUESDAY NIGHT.
HIGH PRESSURE WILL BUILD IN FOR THE MIDDLE PART OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FOR THE MORNING UPDATE WE HAVE DECREASED POPS FOR THE REMAINDER OF
THE MORNING HOURS ACROSS THE NORTHERNEASTERN HALF OF THE CWA WHILE
THE SOUTHWESTERN HALF STILL REMAINS IN AN AREA OF BETTER MOISTURE
TRANSPORT. THE MAIN DIFFERENCE AT THIS POINT, WHEN COMPARED TO
SATURDAY, IS THE AMOUNT OF CLOUD COVER IN PLACE. THINKING THE
CURRENT CLOUD COVER WOULD BE ENOUGH TO INHIBIT THE AMOUNT OF
INSTABILITY TO WORK WITH THIS AFTERNOON BUT ANY BREAKS WOULD ALLOW
FOR POCKETS OF BETTER HEATING AND THEREFORE HIGHER CAPE VALUES.
HI-RES GUIDANCE PAINTS NUMEROUS BULLS-EYES ACROSS OUR WESTERN
AND NORTHERN ZONES AS SHORTWAVE ENERGY UNDERCUTS THE BUILDING
MID-LEVEL RIDGING WORKING INTO THE REGION. WE FOLLOWED HRRR AND
RAP GUIDANCE TO INCREASE POPS TO LIKELY THIS AFTERNOON AND
EVENING, HIGHEST FOR OUR WESTERN ZONES.
TEMPERATURE-WISE, ANOTHER WARM AND ABOVE-AVERAGE MAY DAY IS IN
STORE, WITH NOTICEABLE HUMIDITY. WE MAINLY TOOK A MET/MAV BLEND WITH
CONTINUITY FOR MAXIMUM TEMPERATURES, AND WE ANTICIPATE HIGHS TO
MAINLY BE IN THE LOWER 80S, EXCEPT SOME 70S ALONG THE COAST AND INTO
THE POCONOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
INTO THIS EVENING AND TONIGHT, ANY SCATTERED TSTORM AND SHOWER
ACTIVITY SHOULD WANE WITH DIMINISHING INSTABILITY AS THE WEAK
BACKDOOR FRONT CONTINUES TO EDGE FARTHER SOUTH THROUGH OUR AREA. WE
DECREASE POPS BACK TO SLIGHT CHANCE/LOW CHANCE FOR LINGERING SHOWERS
FROM EAST TO WEST ACROSS THE FORECAST AREA AS THE NIGHT PROGRESSES.
WITH THE PASSAGE OF THE WEAK FRONTAL BOUNDARY THROUGH MOST OF THE
FORECAST AREA AND A WEAK AREA OF HIGH PRESSURE BUILDING DOWN FROM
THE NORTHEAST STATES, MORE OF A NORTHEASTERLY, ONSHORE FLOW IS
EXPECTED TO DEVELOP OVERNIGHT AND INTO THE EARLY MORNING LEADING UP
TO DAYBREAK MONDAY. THIS WILL ALLOW SOME LOW CLOUDS TO DEVELOP
ACROSS THE REGION, WITH PERHAPS SOME PATCHY/AREAS OF FOG.
TEMPERATURES WILL ONCE AGAIN REMAIN MILD THROUGH THE OVERNIGHT, WITH
LOWS MAINLY IN THE 60S ACROSS THE REGION.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MON THRU TUE NIGHT...A CONTINUATION OF THE UNSETTLED PERIOD. WARM
AND HUMID CONDITIONS AND A COLD FRONT TO CROSS THE AREA TUE/TUE
NIGHT. CHC FOR TSTMS MON THEN LIKELY SHOWERS/TSTMS FOR MON NIGHT
INTO TUE. SPC MENTIONS A MARGINAL RISK FOR SVR TSTMS TUE. DECREASING
POPS TUE NIGHT. TEMPS ABOVE NORMAL.
WED THRU SAT...HIGH PRESSURE EXTENDS ACROSS THE AREA. A DRY PERIOD
EXPECTED. TEMPERATURES NEAR NORMAL FOR THE LATER HALF OF MAY.
HIGHS MOSTLY LOW/MID 70S WITH LOWS IN THE 40S NORTH AND 50S SOUTH.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REST OF TODAY...VFR CEILINGS ARE ANTICIPATED TO CONTINUE THROUGH
THE DAY, WITH SOME SCATTERED SHWRS/TSTORMS POSSIBLE. THE BEST
TIMING FOR THIS ACTIVITY LOOKS TO BE IN THE AFTERNOON AND EVENING,
AND THIS HAS BEEN INCLUDED IN THE TAFS. THUNDER WAS NOT INCLUDED,
THOUGH, AS CONFIDENCE IN THE TIMING AND COVERAGE OF TSTORMS IS TOO
UNCERTAIN AT THIS TIME. WESTERLY WINDS INCREASING UP TO AROUND 10
KNOTS ARE EXPECTED THROUGH THE DAYTIME.
TONIGHT...ANY SCATTERED SHWRS/TSTORMS ARE EXPECTED TO DIMINISH TO
MORE ISOLATED ACTIVITY INTO TONIGHT, WITH WESTERLY WINDS FALLING OFF
TO AROUND 5 KNOTS. DURING THE EARLY MORNING HOURS LEADING UP TO
DAYBREAK MONDAY, AN ONSHORE FLOW WILL BEGIN TO DEVELOP ACROSS THE
REGION, WITH NORTHEASTERLY WINDS IN THE 5 TO 8 KNOT RANGE. THE
CONTINUED LOW LEVEL MOISTURE IN PLACE WILL ALLOW CIGS/VSBYS TO FALL
TO MVFR OR LOCALIZED IFR CONDITIONS.
OUTLOOK...
MON THRU TUE NIGHT...MOSTLY VFR EXCEPT IN SCT SHOWERS/TSTMS.
WED THRU THU...MOSTLY VFR.
&&
.MARINE...
SUB-ADVISORY CONDITIONS ARE ANTICIPATED TO CONTINUE FOR THE COASTAL
WATERS AND DELAWARE BAY THROUGH TODAY AND TONIGHT. SOME WIND GUSTS
BETWEEN 15 TO 20 KNOTS ARE POSSIBLE THROUGH THE DAYTIME OVER THE
WATERS, WITH SEAS AVERAGING 3 TO 4 FEET FOR THE COASTAL WATERS AND
AROUND 2 FEET FOR DELAWARE BAY.
OUTLOOK...
MON THRU TUE NIGHT...SUB-SCA CONDITIONS WITH SCT TSTMS.
WED THRU THU...SUB-SCA CONDITIONS. FAIR WEATHER.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...HEAVENER/KLINE
SHORT TERM...KLINE
LONG TERM...O`HARA
AVIATION...KLINE/O`HARA
MARINE...KLINE/O`HARA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
623 AM EDT SUN MAY 17 2015
.SYNOPSIS...
A WEAK FRONT WILL REMAIN ACROSS THE REGION TODAY AND TONIGHT. WEAK
HIGH PRESSURE WILL BE ACROSS THE AREA MONDAY. A LOW PRESSURE SYSTEM
WILL MOVE ACROSS THE UPPER GREAT LAKES AND SOUTHERN CANADA BRINGING
ITS ATTACHED FRONTS TO OUR AREA MONDAY NIGHT THROUGH TUESDAY NIGHT.
HIGH PRESSURE WILL BUILD IN FOR THE MIDDLE PART OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MAINLY CLOUDY CONDITIONS, ISOLATED SHOWERS, AND EVEN SOME PATCHY FOG
ARE EXPECTED AT THE START OF THE DAY, WITH AMPLE LOW LEVEL MOISTURE
REMAINING ACROSS THE REGION. WHILE ANY PATCHY FOG SHOULD DISSIPATE
EARLY ON, THE CLOUDS ARE EXPECTED TO REMAIN THROUGH THE DAY, WITH
ONLY A FEW BREAKS POSSIBLE. AN UPPER LEVEL RIDGE WILL BE IN PLACE
OVER THE REGION THROUGH THE DAY, WITH A WEAK FRONTAL BOUNDARY DRAPED
TO OUR NORTH INTO NEW YORK STATE. THE AMPLE MOISTURE IN PLACE AND
THIS WEAK BOUNDARY PERHAPS EDGING SOUTHWARD THROUGH THE DAY WILL
YIELD SOME ISOLATED TO SCATTERED SHOWERS ACROSS OUR REGION, AND
PERHAPS SOME THUNDER INTO THE AFTERNOON AND EVENING, DEPENDING ON
DEVELOPING INSTABILITY THROUGH THE DAYTIME. WE FOLLOWED HRRR AND RAP
GUIDANCE TO INCREASE POPS TO LIKELY THIS AFTERNOON AND EVENING,
HIGHEST FOR OUR WESTERN ZONES.
TEMPERATURE-WISE, ANOTHER WARM AND ABOVE-AVERAGE MAY DAY IS IN
STORE, WITH NOTICEABLE HUMIDITY. WE MAINLY TOOK A MET/MAV BLEND WITH
CONTINUITY FOR MAXIMUM TEMPERATURES, AND WE ANTICIPATE HIGHS TO
MAINLY BE IN THE LOWER 80S, EXCEPT SOME 70S ALONG THE COAST AND INTO
THE POCONOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
INTO THIS EVENING AND TONIGHT, ANY SCATTERED TSTORM AND SHOWER
ACTIVITY SHOULD WANE WITH DIMINISHING INSTABILITY AS THE WEAK
BACKDOOR FRONT CONTINUES TO EDGE FARTHER SOUTH THROUGH OUR AREA. WE
DECREASE POPS BACK TO SLIGHT CHANCE/LOW CHANCE FOR LINGERING SHOWERS
FROM EAST TO WEST ACROSS THE FORECAST AREA AS THE NIGHT PROGRESSES.
WITH THE PASSAGE OF THE WEAK FRONTAL BOUNDARY THROUGH MOST OF THE
FORECAST AREA AND A WEAK AREA OF HIGH PRESSURE BUILDING DOWN FROM
THE NORTHEAST STATES, MORE OF A NORTHEASTERLY, ONSHORE FLOW IS
EXPECTED TO DEVELOP OVERNIGHT AND INTO THE EARLY MORNING LEADING UP
TO DAYBREAK MONDAY. THIS WILL ALLOW SOME LOW CLOUDS TO DEVELOP
ACROSS THE REGION, WITH PERHAPS SOME PATCHY/AREAS OF FOG.
TEMPERATURES WILL ONCE AGAIN REMAIN MILD THROUGH THE OVERNIGHT, WITH
LOWS MAINLY IN THE 60S ACROSS THE REGION.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MON THRU TUE NIGHT...A CONTINUATION OF THE UNSETTLED PERIOD. WARM
AND HUMID CONDITIONS AND A COLD FRONT TO CROSS THE AREA TUE/TUE
NIGHT. CHC FOR TSTMS MON THEN LIKELY SHOWERS/TSTMS FOR MON NIGHT
INTO TUE. SPC MENTIONS A MARGINAL RISK FOR SVR TSTMS TUE. DECREASING
POPS TUE NIGHT. TEMPS ABOVE NORMAL.
WED THRU SAT...HIGH PRESSURE EXTENDS ACROSS THE AREA. A DRY PERIOD
EXPECTED. TEMPERATURES NEAR NORMAL FOR THE LATER HALF OF MAY.
HIGHS MOSTLY LOW/MID 70S WITH LOWS IN THE 40S NORTH AND 50S SOUTH.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
EARLY MORNING...MOST OF THE TAF SITES WILL START THE DAY WITH VFR
CONDITIONS. SOME MVFR VSBYS REMAIN FOR THE MORE RURAL, SHELTERED
AREAS WHERE AMPLE LOW-LEVEL MOISTURE ALLOWED SOME GENERALLY LIGHT
FOG TO DEVELOP, NAMELY AT KRDG/KABE/KTTN. WINDS OVERALL THIS
MORNING WILL START OUT LIGHT AND VARIABLE OR AT A WEST-SOUTHWEST
DIRECTION AT 5 KNOTS OR LESS.
REST OF TODAY...ANY REMAINING MVFR VSBYS ARE EXPECTED TO IMPROVE
TO VFR CONDITIONS BY ABOUT 13Z ACROSS THE REGION. VFR CEILINGS ARE
ANTICIPATED TO CONTINUE THROUGH THE DAY, WITH SOME SCATTERED
SHWRS/TSTORMS POSSIBLE. THE BEST TIMING FOR THIS ACTIVITY LOOKS TO
BE IN THE AFTERNOON AND EVENING, AND THIS HAS BEEN INCLUDED IN THE
TAFS. THUNDER WAS NOT INCLUDED, THOUGH, AS CONFIDENCE IN THE
TIMING AND COVERAGE OF TSTORMS IS TOO UNCERTAIN AT THIS TIME.
WESTERLY WINDS INCREASING UP TO AROUND 10 KNOTS ARE EXPECTED
THROUGH THE DAYTIME.
TONIGHT...ANY SCATTERED SHWRS/TSTORMS ARE EXPECTED TO DIMINISH TO
MORE ISOLATED ACTIVITY INTO TONIGHT, WITH WESTERLY WINDS FALLING OFF
TO AROUND 5 KNOTS. DURING THE EARLY MORNING HOURS LEADING UP TO
DAYBREAK MONDAY, AN ONSHORE FLOW WILL BEGIN TO DEVELOP ACROSS THE
REGION, WITH NORTHEASTERLY WINDS IN THE 5 TO 8 KNOT RANGE. THE
CONTINUED LOW LEVEL MOISTURE IN PLACE WILL ALLOW CIGS/VSBYS TO FALL
TO MVFR OR LOCALIZED IFR CONDITIONS.
OUTLOOK...
MON THRU TUE NIGHT...MOSTLY VFR EXCEPT IN SCT SHOWERS/TSTMS.
WED THRU THU...MOSTLY VFR.
&&
.MARINE...
SUB-ADVISORY CONDITIONS ARE ANTICIPATED TO CONTINUE FOR THE COASTAL
WATERS AND DELAWARE BAY THROUGH TODAY AND TONIGHT. SOME WIND GUSTS
BETWEEN 15 TO 20 KNOTS ARE POSSIBLE THROUGH THE DAYTIME OVER THE
WATERS, WITH SEAS AVERAGING 3 TO 4 FEET FOR THE COASTAL WATERS AND
AROUND 2 FEET FOR DELAWARE BAY.
OUTLOOK...
MON THRU TUE NIGHT...SUB-SCA CONDITIONS WITH SCT TSTMS.
WED THRU THU...SUB-SCA CONDITIONS. FAIR WEATHER.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...KLINE
SHORT TERM...KLINE
LONG TERM...O`HARA
AVIATION...KLINE/O`HARA
MARINE...KLINE/O`HARA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1201 PM EDT SUN MAY 17 2015
.SYNOPSIS...
16Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW AN AMPLIFIED
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. A LONGWAVE TROUGH
WITH A NOW HIGHLY NEGATIVE TILT IS PIVOTING NORTHWARD THROUGH THE
CENTRAL/NORTHERN PLAINS AND UPPER MIDWEST...WHILE DOWNSTREAM WE
FIND AMPLIFIED RIDGING OVER THE EASTERN THIRD OF THE NATION...
INCLUDING THE FL PENINSULA. THE 12Z KTBW SOUNDING SHOWS A FAIRLY
MOIST COLUMN WITH A PW VALUE OF OVER 1.5"...AND LITTLE OVERALL
RESISTANCE TO PARCEL LIFT. LOW AND MID LEVEL LAPSE RATES ARE RIGHT
AROUND 6C/KM. ONCE AGAIN...WE DO NOT SEE ANY SIGNIFICANT LAYERS
OF HOSTILE AIR TOWARD DEEP CONVECTION WITH MINIMUM THETAE VALUES
WITHIN THE 700-500MB LAYER ALL GENERALLY ABOVE 322K. THE SOUNDING
SHOWS WHAT WOULD BE EXPECTED UNDER THE MIDDLE OF A BIG UPPER
RIDGE...AND THAT IS WEAK...ALMOST VARIABLE FLOW THROUGH THE TROP
COLUMN. THIS WEAK FLOW IS GOING TO RESULT IN SLOW STORM MOTION
TODAY AS WELL. IF THE DEGREE OF THUNDERSTORM DEVELOPMENT EXPECTED
COMES TO PASS...THEN THE THREAT OF LOCALIZED FLOODING EXISTS
TODAY...ESPECIALLY IF ANY OF THE STORMS MIGRATE OVER URBAN
CENTERS.
AT THE SURFACE...ATLANTIC HIGH PRESSURE HAS SETTLED A BIT SOUTH
DURING THE PAST 24 HOURS...AND NOW RIDGES BACK WESTWARD TO NEAR
OR JUST NORTH OF THE I-10 CORRIDOR. THE RESULTING SYNOPTIC FLOW
PATTERN (1000-700MB) ACROSS OUR REGION IS 5-10 KNOTS FROM THE
E/SE. SOUNDING SHOWED PLENTY OF LOW LEVEL MOISTURE IN PLACE...AND
DIURNAL MIXING HAS ALREADY RESULTED IN A SCT-BKN CUMULUS FIELDS
ACROSS BASICALLY THE ENTIRE FL PENINSULA THIS MIDDAY. REGIONAL
RADARS ARE EVEN SHOWING A FEW SCT SHOWERS INLAND FROM THE I-75
CORRIDOR. THESE ARE JUST THE PRECURSOR TO THE MORE VIGEROUS
CONVECTION EXPECTED ALONG AND INSIDE THE I-75 CORRIDOR LATER
TODAY.
&&
.UPDATE (REST OF TODAY AND TONIGHT)... AS MENTIONED IN THE
SYNOPSIS OUR LARGE SCALE FLOW PATTERN IS 5-10 KNOTS FROM THE EAST
TO SOUTHEAST TODAY. THIS MODERATE SOUTHEAST FLOW IS GENERALLY OUR
MOST ACTIVE SUMMER THUNDERSTORM REGIME...AS IT BOTH TENDS TO BE
ASSOCIATED WITH A MOIST PATTERN...AND ALSO PROVIDES THE
MECHANISMS FOR ENHANCED LOW LEVEL FOCUS/CONVERGENCE ALONG THE WEST
COAST SEABREEZE. YESTERDAY...WHERE THE SEA-BREEZE WAS ABLE TO MAKE
A BIT OF SMALL PROGRESS INLAND (BASICALLY SOUTH OF TAMPA
BAY)...THIS CONVERGENCE WAS EFFICIENT AND THUNDERSTORMS ERUPTED
VERY CLOSE TO THE COAST LATE IN THE AFTERNOON. TODAY...THE FLOW
JUST ABOVE THE SURFACE APPEARS LIGHT ENOUGH TO ALLOW THIS MORE
EFFICIENT CONVERGENCE TO OCCUR ALONG MUCH...IF NOT ALL OF THE
FLORIDA WEST COAST. THEREFORE...THINK WE WILL SEE THE ACTIVE
CONVECTION EXPAND NORTHWARD TODAY INTO THE TAMPA BAY AREA...AND
EVEN NORTHWARD THROUGH QUITE A BIT OF THE NATURE COAST. THE LAST
SEVERAL HRRR GUIDANCE RUNS THIS MORNING HAVE BEEN VERY AGGRESSIVE
WITH THE CONVECTION ALONG OUR ENTIRE I-75 CORRIDOR...AND GIVEN THE
FAVORABLE SYNOPTICS...SEE LITTLE REASON TO DISAGREE WITH ITS
GENERAL OUTPUT. RAIN CHANCES IN THE 60-70% RANGE SEEM REASONABLE
ALONG THE GENERAL I-75 CORRIDOR NORTHWARD TO NEAR BROOKSVILLE...
AND THEN WILL HAVE 50% FOR THE FAR NORTHERN ZONES. BTW...THE HRRR
DID A VERY GOOD JOB WITH THE PLACEMENT AND TIMING OF THE
CONVECTION ON SATURDAY...SHOWING CONVECTIVE COVERAGE MAINLY
EXTENDING FROM MANATEE COUNTY SOUTHWARD ALONG THE COAST DURING
THE MORNING RUNS. THIS VERIFIED VERY WELL.
THERE IS NOT A WHOLE LOT OF MOTION IN THE ATMOSPHERE SITTING UNDER
THE MIDDLE OF THE UPPER RIDGE...AND THEREFORE STORMS ARE NOT GOING
TO BE FAST MOVERS...PROPELLED ALONG BY WEAK FLOW...AND/OR OUTFLOW
BOUNDARY MOVEMENT. THE GENERAL MOTION SHOULD BE TOWARD THE COAST
AND EVENTUALLY OFFSHORE. HOWEVER...THE SLOW MOTION IS GOING TO
RESULT IN A HEAVY RAIN/LOCALIZED FLOODING THREAT. ALL OF THE
CONVECTION ALLOWING GUIDANCE IS SHOWING THE POTENTIAL FOR
IMPRESSIVE UPDRAFT VELOCITY VALUES AS WELL (MAXIMUM VALUES ON THE
ORDER OF 14-18M/S). THE STRONG UPDRAFTS WOULD BE CORRELATED WITH
VERY EFFICIENT LIGHTING PRODUCTION AS WELL.
ACTIVITY LINGERS INTO THE EVENING HOURS...AND MAY EVEN PEAK IN
SOME SPOTS BETWEEN 6-9PM. THEREAFTER...MOST GUIDANCE MEMBERS SHOW
THE STORMS MIGRATING OFFSHORE INTO THE EASTERN GULF AND WEAKENING.
WILL SLOWLY RAMP DOWN POPS NEAR THE COAST THROUGH THE MID/LATE
EVENING...AND RETURN ALL AREAS TO A DRY FORECAST AFTER MIDNIGHT.
THE LOW LEVEL MOISTURE WILL KEEP US SEASONABLY WARM OVERNIGHT...
WITH MOST SPOTS SEEING LOW TEMPS BY SUNRISE IN THE UPPER 60S TO
LOWER 70S.
&&
.AVIATION...
VFR CONDITIONS LATE THIS MORNING ACROSS WEST-CENTRAL FLORIDA.
SCT-BKN CUMULUS FIELD HAS ALREADY DEVELOPED AND WILL BE WITH US
THE REST OF THE DAY...WITH BASES RAISING FROM AROUND 3KFT TO 5KFT
THROUGH THE AFTERNOON. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
THE I-75 CORRIDOR THIS AFTERNOON AND PROGRESS WESTWARD TOWARD THE
COAST AFTER DEVELOPMENT. HAVE INCLUDED TEMPOS FOR THE EXPECTED
CONVECTION. ACTIVITY WILL PROGRESS OFFSHORE BY LATE EVENING.
&&
.MARINE...
GENERAL EAST TO SOUTHEAST WINDS WILL REMAIN IN PLACE THROUGH THE
REST OF TODAY WITH WINDS TURNING ONSHORE FOR A TIME THE COAST THIS
AFTERNOON. SHOWERS AND THUNDERSTORMS THAT DEVELOP OVER THE LAND
TODAY WILL SHIFT WESTWARD TOWARD THE COASTAL WATERS EARLY THIS
EVENING. BOATERS ON THE COASTAL WATERS AND BAYS SHOULD KEEP A
CLOSE WATCH ON THE WEATHER AND BE PREPARED TO SEEK SAFE HARBOR
QUICKLY...AS STORMS ARE LIKELY TO RAPIDLY DEVELOP AND MOVE
OFFSHORE. BY TUESDAY AND THROUGH THE REST OF THE WEEK...WIND FLOW
WILL BECOME MORE WESTERLY...AND KEEP THE MAJORITY OF THE STORMS
INLAND. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW HEADLINE
CRITERIA.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 73 89 74 / 70 50 40 30
FMY 90 71 91 73 / 70 40 40 30
GIF 90 72 91 72 / 50 10 40 10
SRQ 88 72 88 73 / 60 50 20 30
BKV 90 70 90 69 / 60 40 40 30
SPG 88 75 89 76 / 60 50 20 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/UPDATE/AVIATION/MARINE...14/MROCZKA
DECISION SUPPORT...RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1009 AM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1008 AM CDT SUN MAY 17 2015
STILL QUITE A FEW QUESTIONS IN REGARDS TO SEVERE WEATHER POTENTIAL
TODAY. EARLIER LINE OF SHOWERS FIZZLED OUT AS IT PASSED I-55...
AND THE REMNANTS ARE LOCATED BETWEEN DECATUR AND CHAMPAIGN PER
LATEST RADAR IMAGERY. GOOD-SIZED CLEAR SLOT ADVANCING ACROSS THE
STATE AT THE MOMENT AND IS RESULTING IN SOME BRIEF SUNNY SKIES
OVER THE NORTHWEST HALF OF THE FORECAST AREA. THIS SHOULD HELP
DESTABILIZE THINGS ACROSS THAT AREA OVER THE NEXT HOUR OR TWO...
AND WE WILL BE DOING A SPECIAL SOUNDING AT NOON TO SAMPLE THE
CHANGES. RAP GUIDANCE SUGGESTING IT MAY TAKE UNTIL EARLY AFTERNOON
TO GET CAPE`S ABOVE 1000 J/KG FURTHER SOUTH. BEST BULK SHEAR TO BE
LOCATED WEST OF I-55...BUT LATEST RAP AND THE 12Z NAM INDICATE
THE BEST POTENTIAL FOR DEVELOPMENT WILL BE EAST OF THERE NEAR THE
REMNANTS OF THE MORNING ACTIVITY. HOWEVER...THE RECENTLY ARRIVED
14Z HRRR IS NOW STARTING TO SHOW SOME ACTIVITY MOVING UP THE
ILLINOIS RIVER VALLEY BEGINNING AROUND 3 PM. SHOWERS IN SOUTHEAST
MISSOURI STARTING TO CROSS INTO SOUTHERN ILLINOIS AS WELL...AND
ANY BOUNDARIES/VORTICES ASSOCIATED WITH THIS AREA MAY COME INTO
PLAY AS WELL.
HAVE SENT OUT SOME REFINEMENTS TO THE POP`S FOR TODAY AND TONIGHT
TO INCORPORATE THE LATEST TRENDS. LITTLE CHANGE TO HIGH
TEMPERATURE AT THE MOMENT.
&&
.SHORT TERM...(TODAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
ANOTHER UNSEASONABLY WARM & MUGGY DAY WITH SOUTHERLY WINDS IS ON TAP
FOR CENTRAL AND SOUTHEAST ILLINOIS TODAY. THIS GENERAL SCENARIO HAS
NOT CHANGED MUCH SINCE YESTERDAY. THE PRIMARY CHANGE EXPECTED FOR
TODAY IS THAT STRONGER DEEP-LAYER SHEAR WILL BE PRESENT, WITH AN
ASSOCIATED INCREASE IN ORGANIZED CONVECTION. THIS WILL BE A CHANGE
FROM THE MOSTLY DISORGANIZED SHOWERS/THUNDERSTORMS OF THE PAST
COUPLE OF DAYS. UNFORTUNATELY, THERE IS QUITE A BIT OF DISAGREEMENT
IN THE CONVECTIVE DETAILS TODAY AMONG THE GUIDANCE. DIFFERENCES ARE
NOT SURPRISING WITH THE SYNOPTIC SCALE MODELS, BUT THEY ARE ALSO
PRESENT IN THE HIGHER RESOLUTION OUTPUT AS WELL. UNDOUBTEDLY, THE
ULTIMATE OUTCOME WILL PROBABLY BE MODULATED BY BOUNDARIES FROM
UPSTREAM CONVECTION THAT MAKES IT INTO AREA AND ASSOCIATED CLOUD
COVER OR LACK THEREOF.
THE REMNANTS OF A PLAINS SQUALL LINE WILL BEGIN TO SPREAD INTO THE
WESTERN PORTION OF THE FORECAST AREA WITHIN THE NEXT COUPLE OF
HOURS. HRRR AND RAP GUIDANCE SUGGEST A RAPID WEAKENING OF THE
STORMS, AND THERE HAS BEEN SIGNIFICANT WEAKENING OF LATE IN RECENT
RADAR LOOPS, AS WELL AS WARMING CLOUD TOPS. THE REMNANTS OF THIS
SYSTEM WILL LIKELY BE KEY TO WHERE THINGS FOCUS IN THE FORECAST AREA
TODAY. MODELS HAVE CONSISTENTLY SUGGESTED CAPE VALUES FROM 1500-2500
J/KG IN THE FORECAST AREA DURING PEAK HEATING TODAY, WHILE BULK
SHEAR VALUES SHOULD BE 35-45 KTS WEST AND 25-35 KTS EAST. THESE
PARAMETERS SUGGEST SOME STRONG TO SEVERE STORMS ARE POSSIBLE IN THE
AREA TODAY, BUT THE EXACT LOCATION/TIMING OF DEVELOPMENT WILL NOT BE
A HIGH CONFIDENCE FORECAST UNTIL WE SEE HOW THINGS PLAY OUT WITH THE
REMNANTS MOVING INTO OUR AREA.
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
00Z FORECAST MODELS TAKE 558 DM 500 MB LOW OVER CENTRAL NEBRASKA NE
INTO NORTHERN MN BY 12Z/MON WHILE 992 MB SURFACE LOW PRESSURE OVER
CENTRAL SD WEAKENS AS IT TRACKS NE INTO NORTHERN MN BY DAWN MONDAY.
THIS WILL BRING AN OCCLUDED FRONT EAST INTO CENTRAL IL NEAR I-55
BY 18Z/MON AND NEARING THE WABASH RIVER BY 00Z/TUE. HIGHEST
CHANCES OF SHOWERS AND THUNDERSTORMS WILL SHIFT INTO EASTERN IL
TONIGHT AND MONDAY. SPC HAS SLIGHT RISK OF SEVERE STORMS OVER ALL
BY FAR SE IL NEAR WABASH RIVER THIS AFTERNOON/EVENING WITH 15%
RISK OF LARGE HAIL AND DAMAGING WIND GUSTS AND 2-5% RISK OF
TORNADOES AND HIGHEST RISK (5%) OVER KNOX...STARK AND MARSHALL
COUNTIES. SPC KEEPS MARGINAL RISK OF SEVERE STORMS MONDAY EAST OF
IL OVER CENTRAL AND EASTERN INDIANA. MILD LOWS TONIGHT IN THE MID
TO UPPER 60S WITH SSW BREEZES. ANOTHER WARM DAY MONDAY WITH HIGHS
IN THE UPPER 70S WEST OF THE IL RIVER AND LOWER 80S EAST OF THE IL
RIVER. SW WINDS TURN WEST AND NW BEHIND COLD FRONT AND DEWPOINTS
WILL BE DROPPING BEHIND THE FRONT DURING THE DAY. THOUGH STAYING
HUMID DURING THE DAY MONDAY OVER SOUTHEAST IL WITH DEWPOINTS IN
THE UPPER 60S TO NEAR 70F.
LINGERED JUST SLIGHT CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORM IN
FAR SE IL NEAR WABASH RIVER MONDAY EVENING. OTHERWISE DRY AND COOLER
AS CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST BY TUE WITH A
FAIR AMOUNT OF SUNSHINE OVER CENTRAL/SE IL TUE WITH NW WINDS. LOWS
MON NIGHT RANGE FROM MID 40S OVER IL RIVER VALLEY TO MID 50S BY
LAWRENCEVILLE. HIGHS TUE RANGE FROM LOWER 60S NORTH OF I-74 TO
AROUND 70F BY LAWRENCEVILLE. ANOTHER COOL NIGHT TUE NIGHT WITH LOWS
IN THE MID TO UPPER 40S.
EXTENDED MODELS CONTINUE TO SHOW A DISTURBANCE EJECTING FROM THE
TROF/CUTOFF LOW NEAR CA INTO THE CENTRAL PLAINS WED AND BRINGING
MAINLY LIGHT QPF INTO CENTRAL AND SW IL WED AND SHIFTING IT
SOUTHWARD WED NIGHT AND THU. HAVE INCREASE POPS BY WED AFTERNOON TO
LIKELY FROM JACKSONVILLE SW WHILE LOWER POPS IN NE CWA BY DANVILLE.
MORE CLOUDS WED AND RAIN CHANCES TO KEEP IT COOLER WITH HIGHS IN
UPPER 50S AND LOWER 60S CENTRAL IL AND MID 60S SOUTHEAST OF I-70.
ANOTHER CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST THU
RETURNING DRY WEATHER AND TEMPS MODERATING DUE TO MORE SUNSHINE WITH
HIGHS IN THE UPPER 60S. SEASONABLE HIGHS REACH THE LOW TO MID 70S
FRIDAY. LOOKS LIKE AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS
DURING THE MEMORIAL DAY WEEKEND ESPECIALLY FROM SAT NIGHT ON WITH
DISTURBANCE EJECTING OUT OF SW UPPER LEVEL FLOW AND INCREASING TEMPS
AND HUMIDITY WITH SOUTHERLY FLOW RETURNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 654 AM CDT SUN MAY 17 2015
AREAS OF IFR/MVFR CONDITIONS WILL BE EVIDENT ACROSS THE CENTRAL
AND SOUTHEAST ILLINOIS TERMINAL AREA TO START THE DAY. A WEAKENING
BAND OF SHOWERS, CURRENTLY SPREADING ACROSS CENTRAL ILLINOIS, MAY
ALSO IMPACT A FEW TAF SITES WITHIN THE NEXT FEW HOURS. CONDITIONS
SHOULD GENERALLY IMPROVE TO VFR BY LATER THIS MORNING, AND THEN WE
WILL HAVE TO WAIT FOR DIURNALLY ENHANCED SHOWERS/STORMS TO
DEVELOP. THE EXACT TIMING AND LOCATION FOR THIS DIURNAL
DEVELOPMENT IS UNCLEAR AT THIS TIME, SO HAVE ONLY INCLUDED A VCTS
MENTION THIS AFTERNOON/EARLY EVENING. GUSTY SOUTHERLY WINDS WILL
DEVELOP FOR MUCH OF THE DAYTIME HOURS TODAY AS WELL. THE
PRECIPITATION CHANCES SHOULD WANE THIS EVENING, WITH VFR
CONDITIONSPERSISTING FOR MUCH OF THE NIGHT. HOWEVER, MVFR FOG,
AND POSSIBLY STRATUS, SHOULD DEVELOP AFTER MIDNIGHT TONIGHT (05Z
MONDAY).
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...07/BAK
LONG TERM...07
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
659 AM CDT SUN MAY 17 2015
.SHORT TERM...(TODAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
ANOTHER UNSEASONABLY WARM & MUGGY DAY WITH SOUTHERLY WINDS IS ON TAP
FOR CENTRAL AND SOUTHEAST ILLINOIS TODAY. THIS GENERAL SCENARIO HAS
NOT CHANGED MUCH SINCE YESTERDAY. THE PRIMARY CHANGE EXPECTED FOR
TODAY IS THAT STRONGER DEEP-LAYER SHEAR WILL BE PRESENT, WITH AN
ASSOCIATED INCREASE IN ORGANIZED CONVECTION. THIS WILL BE A CHANGE
FROM THE MOSTLY DISORGANIZED SHOWERS/THUNDERSTORMS OF THE PAST
COUPLE OF DAYS. UNFORTUNATELY, THERE IS QUITE A BIT OF DISAGREEMENT
IN THE CONVECTIVE DETAILS TODAY AMONG THE GUIDANCE. DIFFERENCES ARE
NOT SURPRISING WITH THE SYNOPTIC SCALE MODELS, BUT THEY ARE ALSO
PRESENT IN THE HIGHER RESOLUTION OUTPUT AS WELL. UNDOUBTEDLY, THE
ULTIMATE OUTCOME WILL PROBABLY BE MODULATED BY BOUNDARIES FROM
UPSTREAM CONVECTION THAT MAKES IT INTO AREA AND ASSOCIATED CLOUD
COVER OR LACK THEREOF.
THE REMNANTS OF A PLAINS SQUALL LINE WILL BEGIN TO SPREAD INTO THE
WESTERN PORTION OF THE FORECAST AREA WITHIN THE NEXT COUPLE OF
HOURS. HRRR AND RAP GUIDANCE SUGGEST A RAPID WEAKENING OF THE
STORMS, AND THERE HAS BEEN SIGNIFICANT WEAKENING OF LATE IN RECENT
RADAR LOOPS, AS WELL AS WARMING CLOUD TOPS. THE REMNANTS OF THIS
SYSTEM WILL LIKELY BE KEY TO WHERE THINGS FOCUS IN THE FORECAST AREA
TODAY. MODELS HAVE CONSISTENTLY SUGGESTED CAPE VALUES FROM 1500-2500
J/KG IN THE FORECAST AREA DURING PEAK HEATING TODAY, WHILE BULK
SHEAR VALUES SHOULD BE 35-45 KTS WEST AND 25-35 KTS EAST. THESE
PARAMETERS SUGGEST SOME STRONG TO SEVERE STORMS ARE POSSIBLE IN THE
AREA TODAY, BUT THE EXACT LOCATION/TIMING OF DEVELOPMENT WILL NOT BE
A HIGH CONFIDENCE FORECAST UNTIL WE SEE HOW THINGS PLAY OUT WITH THE
REMNANTS MOVING INTO OUR AREA.
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
00Z FORECAST MODELS TAKE 558 DM 500 MB LOW OVER CENTRAL NEBRASKA NE
INTO NORTHERN MN BY 12Z/MON WHILE 992 MB SURFACE LOW PRESSURE OVER
CENTRAL SD WEAKENS AS IT TRACKS NE INTO NORTHERN MN BY DAWN MONDAY.
THIS WILL BRING AN OCCLUDED FRONT EAST INTO CENTRAL IL NEAR I-55
BY 18Z/MON AND NEARING THE WABASH RIVER BY 00Z/TUE. HIGHEST
CHANCES OF SHOWERS AND THUNDERSTORMS WILL SHIFT INTO EASTERN IL
TONIGHT AND MONDAY. SPC HAS SLIGHT RISK OF SEVERE STORMS OVER ALL
BY FAR SE IL NEAR WABASH RIVER THIS AFTERNOON/EVENING WITH 15%
RISK OF LARGE HAIL AND DAMAGING WIND GUSTS AND 2-5% RISK OF
TORNADOES AND HIGHEST RISK (5%) OVER KNOX...STARK AND MARSHALL
COUNTIES. SPC KEEPS MARGINAL RISK OF SEVERE STORMS MONDAY EAST OF
IL OVER CENTRAL AND EASTERN INDIANA. MILD LOWS TONIGHT IN THE MID
TO UPPER 60S WITH SSW BREEZES. ANOTHER WARM DAY MONDAY WITH HIGHS
IN THE UPPER 70S WEST OF THE IL RIVER AND LOWER 80S EAST OF THE IL
RIVER. SW WINDS TURN WEST AND NW BEHIND COLD FRONT AND DEWPOINTS
WILL BE DROPPING BEHIND THE FRONT DURING THE DAY. THOUGH STAYING
HUMID DURING THE DAY MONDAY OVER SOUTHEAST IL WITH DEWPOINTS IN
THE UPPER 60S TO NEAR 70F.
LINGERED JUST SLIGHT CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORM IN
FAR SE IL NEAR WABASH RIVER MONDAY EVENING. OTHERWISE DRY AND COOLER
AS CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST BY TUE WITH A
FAIR AMOUNT OF SUNSHINE OVER CENTRAL/SE IL TUE WITH NW WINDS. LOWS
MON NIGHT RANGE FROM MID 40S OVER IL RIVER VALLEY TO MID 50S BY
LAWRENCEVILLE. HIGHS TUE RANGE FROM LOWER 60S NORTH OF I-74 TO
AROUND 70F BY LAWRENCEVILLE. ANOTHER COOL NIGHT TUE NIGHT WITH LOWS
IN THE MID TO UPPER 40S.
EXTENDED MODELS CONTINUE TO SHOW A DISTURBANCE EJECTING FROM THE
TROF/CUTOFF LOW NEAR CA INTO THE CENTRAL PLAINS WED AND BRINGING
MAINLY LIGHT QPF INTO CENTRAL AND SW IL WED AND SHIFTING IT
SOUTHWARD WED NIGHT AND THU. HAVE INCREASE POPS BY WED AFTERNOON TO
LIKELY FROM JACKSONVILLE SW WHILE LOWER POPS IN NE CWA BY DANVILLE.
MORE CLOUDS WED AND RAIN CHANCES TO KEEP IT COOLER WITH HIGHS IN
UPPER 50S AND LOWER 60S CENTRAL IL AND MID 60S SOUTHEAST OF I-70.
ANOTHER CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST THU
RETURNING DRY WEATHER AND TEMPS MODERATING DUE TO MORE SUNSHINE WITH
HIGHS IN THE UPPER 60S. SEASONABLE HIGHS REACH THE LOW TO MID 70S
FRIDAY. LOOKS LIKE AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS
DURING THE MEMORIAL DAY WEEKEND ESPECIALLY FROM SAT NIGHT ON WITH
DISTURBANCE EJECTING OUT OF SW UPPER LEVEL FLOW AND INCREASING TEMPS
AND HUMIDITY WITH SOUTHERLY FLOW RETURNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 654 AM CDT SUN MAY 17 2015
AREAS OF IFR/MVFR CONDTIONS WILL BE EVIDENT ACROSS THE CENTRAL AND
SOUTHEAST ILLINOIS TERMINAL AREA TO START THE DAY. A WEAKENING BAND
OF SHOWERS, CURRENTLY SPREADING ACROSS CENTRAL ILLINOIS, MAY ALSO
IMPACT A FEW TAF SITES WITHIN THE NEXT FEW HOURS. CONDTIONS SHOULD
GENERALLY IMPROVE TO VFR BY LATER THIS MORNING, AND THEN WE WILL
HAVE TO WAIT FOR DIURNALLY ENHANCED SHOWERS/STORMS TO DEVELOP. THE
EXACT TIMING AND LOCATION FOR THIS DIURNAL DEVELOPMENT IS UNCLEAR
AT THIS TIME, SO HAVE ONLY INCLUDED A VCTS MENTION THIS
AFTERNOON/EARLY EVENING. GUSTY SOUTHERLY WINDS WILL DEVELOP FOR
MUCH OF THE DAYTIME HOURS TODAY AS WELL. THE PRECIPITATION CHANCES
SHOULD WANE THIS EVENING, WITH VFR CONDTIONS PERSISTING FOR MUCH
OF THE NIGHT. HOWEVER, MVFR FOG, AND POSSIBLY STRATUS, SHOULD
DEVELOP AFTER MIDNIGHT TONIGHT (05Z MONDAY)
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...07/BAK
LONG TERM...07
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
716 AM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 715 AM CDT SUN MAY 17 2015
ONLY A FEW SHOWERS WERE NOTED ON RADAR IN THE DVN CWA AND MOST OF
THOSE WERE OCCURING IN OUR FAR WESTERN COUNTIES. I HAVE REMOVED
THE MENTION OF THUNDER THROUGH THE MID MORNING HOURS AT LEAST.
OTHERWISE...EXTENSIVE CLOUD COVER WILL BE SEEN THIS MORNING. THE
LATEST MESO MODEL RUNS INDICATE MUCH OF THE CWA TO REMAIN DRY
TODAY SO CONFIDENCE REMAINS LOW WITH REGARD TO THE COVERAGE OF
CONVECTION.
&&
.SYNOPSIS...
ISSUED AT 340 AM CDT SUN MAY 17 2015
SYNOPSIS...HUGE SQUALL LINE OF SEVERE STORMS AND EMBEDDED TORNADOES
EXTENDED ALL THE WAY FROM NORTHERN MO TO CENTRAL TX. HOWEVER...THE
FAR NORTHERN PORTION OF THE LINE APPROACHING NORTHEAST MO AND
SOUTHCENTRAL IA WAS RAPIDLY WEAKENING AS IT RUNS INTO MUCH MORE
STABLE AIR WITH MINIMAL CAPE. ALSO...IR SATELLITE SHOWS RAPIDLY
WARMING TOPS. MEANWHILE BACK AT THE RANCH...LOW STRATUS HAS FORMED
OVER MUCH OF THE CWA DUE TO CONTINUED MOISTURE TRANSPORT FROM THE
SOUTH. 3 AM TEMPERATURES RANGED FROM THE MID 60S TO AROUND 70 WITH
DEWPOINTS IN THE MID 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SUN MAY 17 2015
FORECAST FOCUS ON SEVERE POTENTIAL AND COVERAGE OF THUNDERSTORMS.
TODAY...SPC HAS SHIFTED THE ENHANCED SEVERE RISK NORTH OF THE CWA
CLOSER TO THE STRONGEST SHEAR AND TRIPLE POINT OF THE OCCLUDING
CYCLONE WITH A SLIGHT RISK OVER ALL OF THE CWA. SPC HAS A 5%
PROBABILITY FOR TORNADOES IN NORTHEAST IA AND NORTHERN IL WITH A 15%
PROBABILITY OF WIND AND HAIL OVER THE ENTIRE CWA. THIS IS A LOW
CONFIDENCE FORECAST OF EXACTLY HOW THE CONVECTION WILL PLAY OUT AS
MODELS DIFFER GREATLY...RANGING FROM NUMEROUS TO ONLY ISOLATED
STORMS.
FIRST OF ALL IS THIS MORNING WITH THE RAPIDLY DECAYING SQUALL LINE
WHICH WILL BE MOVING INTO OUR WESTERN AND SOUTHERN CWA EARLY THIS
MORNING...SO WILL HAVE LIKELY POPS FOR THOSE AREAS. THE HRRR MODEL
TAKES THIS WEAK LINE OVER ALL OF EASTERN IA TO ABOUT THE MS RIVER
THEN FADES IT BY MID MORNING...SO WILL HAVE CHANCE POPS THE FARTHER
EAST YOU GO INTO THE CWA. THEN WE HAVE THE LOW STRATUS FOR MUCH OF
THE MORNING WITH THE AVIATION GFS-LAMP GUIDANCE INDICATING THIS TO
DISSIPATE BY LATE MORNING/EARLY AFTERNOON SIMILAR TO YESTERDAY.
THIS AFTERNOON...COVERAGE OF THUNDERSTORMS IS PROBLEMATIC AS MODELS
HAVE DIFFERING SOLUTIONS. MODELS STILL INDICATE STRONG DEEP LAYER
SHEAR WITH 0-6KM OF 40-45 KTS AIDED BY CYCLONICALLY CURVED JET FROM
MID MISSISSIPPI VALLEY INTO GREAT LAKES. TEMPERATURES IN THE LOWER
TO MID 80S AND DEWPTS IN THE MID TO UPPER 60S SHOULD YIELD MODERATE
INSTABILITY WITH MLCAPES OF 1000-2000 J/KG. THIS IS CERTAINLY
SUFFICIENT TO SUPPORT ALL MODES OF SEVERE WEATHER. HOWEVER...WITH
THE OCCLUDING CYCLONE WE ARE ALSO LOSING THE FORCING/LOW LEVEL
CONVERGENCE TO GET STORMS TO DEVELOP...EXCEPT IN OUR FAR EASTERN
COUNTIES EARLY THIS AFTERNOON. THIS WILL BE INTERESTING TO SEE HOW
THIS PLAYS OUT BUT FOR NOW WILL HAVE THE HIGHEST POPS IN THE EAST
AND ONLY SLIGHT POPS IN THE SW. MAXIMUM TEMPERATURES SHOULD GET INTO
THE LOWER TO MID 80S AT MOST LOCATIONS.
TONIGHT...I WILL MAINTAIN THE SMALL POPS FOR EARLY THIS EVENING
ALONG AND EAST OF THE MS RIVER BUT WE COULD JUST AS EASILY BE DRY.
OPERATIONAL MODELS INDICATE DRY SLOT TO SPREAD OVER ALL THE CWA AS
THE OCCLUDING CYCLONE TRACKS INTO THE MN ARROWHEAD. SKIES WILL BE
CLEARING OR CLEAR WITH COOLER AND DRIER AIR BEGINNING TO PUSH INTO
THE NW CWA OVERNIGHT. MINIMUM TEMPERATURES WILL RANGE FROM THE MID
50S NW TO THE LOWER TO MID 60S SE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN MAY 17 2015
COOL BUT NICE MID MAY WEATHER FOR THE UPCOMING WORK WEEK WITH SOME
LIGHT RAIN POSSIBLE WEDNESDAY.
LONG TERM FORECAST CONFIDENCE ASSESSMENT...GOOD OR ABOVE AVERAGE WITH
LITTLE SENSIBLE WEATHER ISSUES. MAIN ISSUE IS DIURNAL TEMPERATURE RANGES
WITH MOST DAYS SUGGESTION OF WIDER RANGES OF HI/LO BY A DEGREE OR SO
MOST LOCATIONS SUPPORTED.
OVERVIEW...INITIALIZATION AND VERIFICATION IS GOOD WITH SLIGHTLY TOO
MOIST BL ISSUES NOTED THAT ARE IMPACTING NORMAL MODEL FIELDS CURRENTLY
AS TOO WIDESPREAD EXCEPT FOR LINEAR FEATURES UNDERDONE. THIS WILL HAVE
NO IMPACT MONDAY ONWARD. RUN TO RUN VARIANCES SUGGEST LITTLE DIFFERENCES
EXCEPT TEMPERATURES BY A CATEGORY OR SO WITH A MEAN TAKEN FOR LATER
SHIFTS TO REASSESS AS AGAIN PROBABLE A DEGREE OR TWO TO COOL/MILD FOR
HIGHS/LOWS MOST DAYS.
MONDAY...STRONG CAA TO RESULT IN BREEZY WEATHER WITH MANY LOCATIONS
TO HAVE NEARLY STEADY TEMPERATURES WITH 15 TO 25+ MPH WITH SOME GUSTS
TO 30 MPH NORTH HALF OF FORECAST AREA. STRONG GRADIENT WITH LOWER 60S
FAR NW TO UPPER 70S FAR SE SECTIONS. MONDAY NIGHT...WINDS MAY BE UP
ENOUGH TO PRECLUDE FROST RISK WITH UPPER 30S NW TO MID 40S SOUTH SECTIONS.
TUESDAY...BELOW NORMAL TEMPERATURES BY 10 TO 15 DEGREES WITH CONTINUED
CAA WITH LOW LEVEL THERMAL FIELDS SUPPORTIVE OF NEAR 60F FAR NORTH TO
MIDDLE 60S SOUTH SECTIONS DESPITE NEARLY FULL TO FULL SUNSHINE.
TUESDAY NIGHT...LIGHT WINDS MAY ALLOW FOR BL DECOUPLING NORTH 1/2
AND PATCHY FROST RISK FOR LATER SHIFT TO RECONSIDER. LOCAL TECHNIQUES
DO SUGGEST WITH FAIR SKIES AND BL DECOUPLING SOME MID 30S POSSIBLE
ALONG AND NORTH OF HIGHWAY 30 CORRIDOR FAVORED LOW LYING LOCATIONS.
WEDNESDAY...INCREASING CLOUDS WITH RISK OF SPRINKLES MOSTLY CENTRAL
SECTIONS AND SOME LIGHT RAIN SOUTH 1/3 OF AREA. HIGHS SHOULD WITH CLOUDS
BE MOSTLY LOWER 60S WITH UPPER 50S POSSIBLE IN HEAVIEST CLOUDS AND
POSSIBLE LIGHT RAIN. WEDNESDAY NIGHT...ANY LIGHT PRECIPITATION SHOULD
END AROUND MIDNIGHT WITH CLEARING SKIES BY MORNING ALL BUT FAR SE
SECTIONS. MINS LOWER TO MIDDLE 40S ARE REASONABLE.
THURSDAY THROUGH SATURDAY...MORE NICE WEATHER WITH UPPER 60S MOST LOCATIONS
FOR HIGHS ON THURSDAY AND LOWER 70S A GOOD REFERENCE POINT FRIDAY/SATURDAY
WITH LOW DEWPOINTS. MINS 40S RISING INTO THE 50S SATURDAY AND SUNDAY
AM WITH PROBABLE MOST LOCATIONS MINS ARE 2 TO 3 PLUS DEGREES TOO MILD
FOR LATER SHIFTS TO CONSIDER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 715 AM CDT SUN MAY 17 2015
OCNL MVFR CIGS THIS MORNING THEN VFR CONDS THIS AFTERNOON AND
TONIGHT AS A COLD FRONT SWEEPS ACROSS THE AREA. LOW CONFIDENCE IN
COVERAGE OF THUNDERSTORMS WITH THE CURRENT THINKING ISOLATED TO
SCATTERED STORMS TO DEVELOP THIS AFTERNOON...MAINLY IN NORTHEAST
IOWA AND NORTHWEST ILLINOIS. SOUTH WINDS SUSTAINED 15 TO 20 KNOTS
WITH GUSTS TO 25 KNOTS TODAY...THEN SOUTHWEST AROUND 10 KNOTS
TONIGHT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...NICHOLS
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1021 AM CDT SUN MAY 17 2015
.UPDATE...
IR SATELLITE SHOWING SOME CLOUD TOP WARMING PERHAPS SIGNALING AN
OVERALL WEAKENING TREND IN A LINE OF SHOWERS AND THUNDERSTORMS
NOTED ON RADAR THIS MORNING ALONG A TOMBALL...HUNSTVILLE...LUFKIN
TX LINE. INSTABILITY IS APPARENT AHEAD OF THIS LINE AS SCATTERED
SHOWERS ARE DEVELOPING ACROSS INTERIOR SOUTHEAST TEXAS EXTENDING
SOUTHWEST INTO THE HOUSTON AREA.
CURRENT FORECAST ON TRACK AS POPS IN LINE WHERE CONVECTION IS
DEVELOPING AND IS FORECAST TO CONTINUE TO DEVELOP MOSTLY ACROSS
OUR NORTHERN AREAS. SOUTHERN AREAS ALONG AND SOUTH OF I-10
CORRIDOR WILL SEE A SLIGHT CHANCE OF AFTERNOON CONVECTION BUT
BELIEVE MID AND HIGH CLOUDS MAY LIMIT ANYTHING MORE.
NO CHANGES FOR ZONE FORECAST PACKAGE. 06
&&
.PREV DISCUSSION... /ISSUED 701 AM CDT SUN MAY 17 2015/
DISCUSSION...
17/12Z TAF ISSUANCE.
AVIATION...
OTHER THAN SOME SHRA EAST OF THE LOWER ATCHAFALAYA BASIN...KLCH
88D SHOWS LITTLE CONVECTION ACRS THE AREA THIS MORNING. WIDESPREAD
LOW CLOUDS WITH BKN CIGS PREVAILING BETWEEN 1000-2000 FT. EXPECT
CIGS TO LIFT TO VFR THROUGH MIDDAY WITH SCT CONVECTION DEVELOPING
AS DAYTIME HEATING INTERACTS WITH A PASSING DISTURBANCE ALOFT AND
AN APPROACHING SFC BOUNDARY OVER TX. GUSTY SLY WINDS CAN AGAIN BE
EXPECTED.
CURRENTLY...A LINE OF STORMS EXTENDS FM NE TX SW TO THE RIO
GRANDE VALLEY. THIS LINE WILL APPROACH SE TX LATER THIS MORNING
AND COULD AFFECT BPT BY MIDDAY IF IT HOLDS TOGETHER. BOTH THE NAM
AND HRRR INDICATE THE NRN END OF THE LINE SHOULD REACH PORTIONS OF
NRN/CNTL LA AS WELL...THUS INCLUDED TEMPO GROUPS AT BOTH AEX AND
BPT. INSERTED PROB30 AFTER 21Z FOR LCH WITH VC AT LFT/ARA AS
UNCERTAINTY INCREASES REGARDING CONVECTIVE EVOLUTION THROUGH THE
AFTN. ACTIVITY SHOULD DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING...WITH MVFR CIGS RETURNING AFTER MIDNIGHT. 24
PREV DISCUSSION... /ISSUED 343 AM CDT SUN MAY 17 2015/
DISCUSSION...
WATER VAPOR CURRENTLY SHOWING SOME DRIER AIR AND SUBSIDENCE ALOFT
ACROSS THE FORECAST AREA...AND LOCAL RADARS ARE ON THE QUIET SIDE
OVER THE IMMEDIATE FORECAST AREA...WITH JUST AN OCCASIONAL LIGHT
POP-UP NOCTURNAL SHOWER.
THE THINKING FOR THE PAST COUPLE OF DAYS HAD BEEN THAT SUNDAY
WOULD SEE LESS ACTIVITY BASED ON THE SOMEWHAT DRIER AIR IN THE MID
LEVELS AND FORECAST AREA WOULD BE BETWEEN SYSTEMS.
HOWEVER...REGIONAL RADAR IMAGES SHOW CLUSTERS OF THUNDERSTORMS
ALONG A LINE EXTENDING FROM THE RED RIVER VALLEY THROUGH CENTRAL
TEXAS JUST WEST OF I-35. THIS ACTIVITY IS NOTED ALONG A SURFACE
TROUGH WITH ENERGY FROM AN UPPER LEVEL DISTURBANCE AT IT KICKS
OUT. PROGS...ESPECIALLY THE LATEST HRRR...IS RATHER BULLISH WITH
KEEPING ACTIVITY TOGETHER AND REACHING THE NORTHERN PORTIONS OF
THE FORECAST AREA THIS AFTERNOON. THEREFORE...WILL HAVE HIGH END
CHANCE FOR SHOWERS AND STORMS ACROSS UPPER SOUTHEAST TEXAS...AND
NORTH OF HIGHWAY 190 IN LOUISIANA...FOR THIS AFTERNOON...WITH LOW
END CHANCE SOUTH OF THIS LINE TO THE COAST. THE MAIN HAZARD WILL
BE LOCALLY HEAVY RAINFALL AND OCCASIONAL TO FREQUENT CLOUD TO
GROUND LIGHTNING.
ACTIVITY THAT DEVELOPS WILL DECREASE IN THE EVENING HOURS WITH THE
LOSS OF DAYTIME HEATING.
AS THE UPPER LEVEL TROUGH CONTINUES TO KICK OFF TO THE NORTHEAST
ON MONDAY...IT WILL PUSH A SURFACE TROUGH INTO THE FORECAST AREA
WHERE IT WILL STALL ROUGHLY ALONG HIGHWAY 190 AND WASH OUT ON
TUESDAY. THE COMBINATION OF A VERY MOIST ENVIRONMENT AND LIFT FROM
THE TROUGH...WILL PRODUCE DECENT RAIN CHANCES...ESPECIALLY
NORTHERN ZONES ON MONDAY INTO TUESDAY...WITH THE BEST CHANCE
DURING THE AFTERNOON...ALTHOUGH ACTIVITY COULD DEVELOP DURING ANY
PART OF THE DAY. CLOUD COVER MAY LIMIT INSTABILITY...ALONG WITH
UPPER LEVEL ENERGY ON THE MODEST SIDE...AND THIS MAY KEEP STORMS
IN CHECK...WITH AGAIN THE MAIN CONCERNS THE HEAVY RAINFALL
POTENTIAL...WITH PWAT BETWEEN 1.8 AND 2 INCHES...AND MEAN RH IN
THE 70 TO 80 PERCENT RANGE.
THE SURFACE BOUNDARY WILL WASH-OUT BY WEDNESDAY...AND WEAK FLAT
UPPER LEVEL RIDGING WILL TRY TO BUILD INTO THE FORECAST AREA.
STILL...PLENTY OF MOISTURE WITH SOUTH FLOW OFF THE GULF. MAIN
KICKER WILL BE DAYTIME HEATING...SO WILL HAVE TYPICAL SUMMERTIME
CONVECTION TYPE POPS FOR THE REMAINDER OF THE FORECAST TO COVER
DIURNAL DRIVEN STORMS.
RUA
MARINE...
MODERATE SOUTHEAST FLOW OCCURRING OVER THE COASTAL WATERS THIS
EARLY MORNING WITH NOCTURNAL LOW LEVEL JET AND INFLOW INTO TROUGH
AND COMPLEX OF STORMS OVER THE RED RIVER VALLEY INTO CENTRAL
TEXAS. SUSTAINED WINDS AT TIMES NEAR 20 KNOTS...AND PROGS SHOW
THIS CONTINUING THROUGH THE MORNING HOURS...UNTIL TROUGH GETS
CLOSER TO THE REGION. THEREFORE...WILL EXTEND SMALL CRAFT EXERCISE
CAUTION THROUGH THE MORNING HOURS.
WINDS AWAY FROM CONVECTION WILL DECREASE LATER THIS AFTERNOON INTO
MONDAY AS SURFACE TROUGH NEARS THE FORECAST AREA...LESSENING THE
GRADIENT ACROSS THE COASTAL WATERS. THIS SURFACE TROUGH WILL STALL
AND WASH OUT NORTH OF THE COASTAL WATERS LATE MONDAY INTO TUESDAY.
THEREFORE...WITH HIGH PRESSURE AT THE SURFACE ANCHORED OFF THE
SOUTHEAST U.S. COAST...SOUTH TO SOUTHEAST WINDS WILL PREVAIL AT
LIGHT TO OCCASIONALLY MODERATE LEVELS THROUGH THE FORECAST PERIOD.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE LATER TODAY AND
MONDAY...WITH UNSTABLE CONDITIONS PREVAILING INTO TUESDAY...AS THE
TROUGH INTERACTS WITH THE MOIST ENVIRONMENT TO PRODUCE SCATTERED
SHOWERS AND THUNDERSTORMS...ESPECIALLY NEAR SHORE OR OVER THE
COASTAL LAKES. WINDS AND SEAS WILL BE LOCALLY HIGHER NEAR THE
STORMS. THE CONVECTION WILL DECREASE IN COVERAGE FOR THE MIDDLE TO
LATE PART OF THE WEEK.
RUA
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 88 73 85 70 / 50 20 60 40
LCH 87 76 87 74 / 30 20 40 20
LFT 87 75 87 73 / 30 20 50 30
BPT 86 76 88 74 / 30 20 40 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL NOON CDT TODAY FOR GMZ450-452-
455-470-472-475.
&&
$$
PUBLIC...06
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
701 AM CDT SUN MAY 17 2015
.DISCUSSION...
17/12Z TAF ISSUANCE.
&&
.AVIATION...
OTHER THAN SOME SHRA EAST OF THE LOWER ATCHAFALAYA BASIN...KLCH
88D SHOWS LITTLE CONVECTION ACRS THE AREA THIS MORNING. WIDESPREAD
LOW CLOUDS WITH BKN CIGS PREVAILING BETWEEN 1000-2000 FT. EXPECT
CIGS TO LIFT TO VFR THROUGH MIDDAY WITH SCT CONVECTION DEVELOPING
AS DAYTIME HEATING INTERACTS WITH A PASSING DISTURBANCE ALOFT AND
AN APPROACHING SFC BOUNDARY OVER TX. GUSTY SLY WINDS CAN AGAIN BE
EXPECTED.
CURRENTLY...A LINE OF STORMS EXTENDS FM NE TX SW TO THE RIO
GRANDE VALLEY. THIS LINE WILL APPROACH SE TX LATER THIS MORNING
AND COULD AFFECT BPT BY MIDDAY IF IT HOLDS TOGETHER. BOTH THE NAM
AND HRRR INDICATE THE NRN END OF THE LINE SHOULD REACH PORTIONS OF
NRN/CNTL LA AS WELL...THUS INCLUDED TEMPO GROUPS AT BOTH AEX AND
BPT. INSERTED PROB30 AFTER 21Z FOR LCH WITH VC AT LFT/ARA AS
UNCERTAINTY INCREASES REGARDING CONVECTIVE EVOLUTION THROUGH THE
AFTN. ACTIVITY SHOULD DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING...WITH MVFR CIGS RETURNING AFTER MIDNIGHT. 24
&&
.PREV DISCUSSION... /ISSUED 343 AM CDT SUN MAY 17 2015/
DISCUSSION...
WATER VAPOR CURRENTLY SHOWING SOME DRIER AIR AND SUBSIDENCE ALOFT
ACROSS THE FORECAST AREA...AND LOCAL RADARS ARE ON THE QUIET SIDE
OVER THE IMMEDIATE FORECAST AREA...WITH JUST AN OCCASIONAL LIGHT
POP-UP NOCTURNAL SHOWER.
THE THINKING FOR THE PAST COUPLE OF DAYS HAD BEEN THAT SUNDAY
WOULD SEE LESS ACTIVITY BASED ON THE SOMEWHAT DRIER AIR IN THE MID
LEVELS AND FORECAST AREA WOULD BE BETWEEN SYSTEMS.
HOWEVER...REGIONAL RADAR IMAGES SHOW CLUSTERS OF THUNDERSTORMS
ALONG A LINE EXTENDING FROM THE RED RIVER VALLEY THROUGH CENTRAL
TEXAS JUST WEST OF I-35. THIS ACTIVITY IS NOTED ALONG A SURFACE
TROUGH WITH ENERGY FROM AN UPPER LEVEL DISTURBANCE AT IT KICKS
OUT. PROGS...ESPECIALLY THE LATEST HRRR...IS RATHER BULLISH WITH
KEEPING ACTIVITY TOGETHER AND REACHING THE NORTHERN PORTIONS OF
THE FORECAST AREA THIS AFTERNOON. THEREFORE...WILL HAVE HIGH END
CHANCE FOR SHOWERS AND STORMS ACROSS UPPER SOUTHEAST TEXAS...AND
NORTH OF HIGHWAY 190 IN LOUISIANA...FOR THIS AFTERNOON...WITH LOW
END CHANCE SOUTH OF THIS LINE TO THE COAST. THE MAIN HAZARD WILL
BE LOCALLY HEAVY RAINFALL AND OCCASIONAL TO FREQUENT CLOUD TO
GROUND LIGHTNING.
ACTIVITY THAT DEVELOPS WILL DECREASE IN THE EVENING HOURS WITH THE
LOSS OF DAYTIME HEATING.
AS THE UPPER LEVEL TROUGH CONTINUES TO KICK OFF TO THE NORTHEAST
ON MONDAY...IT WILL PUSH A SURFACE TROUGH INTO THE FORECAST AREA
WHERE IT WILL STALL ROUGHLY ALONG HIGHWAY 190 AND WASH OUT ON
TUESDAY. THE COMBINATION OF A VERY MOIST ENVIRONMENT AND LIFT FROM
THE TROUGH...WILL PRODUCE DECENT RAIN CHANCES...ESPECIALLY
NORTHERN ZONES ON MONDAY INTO TUESDAY...WITH THE BEST CHANCE
DURING THE AFTERNOON...ALTHOUGH ACTIVITY COULD DEVELOP DURING ANY
PART OF THE DAY. CLOUD COVER MAY LIMIT INSTABILITY...ALONG WITH
UPPER LEVEL ENERGY ON THE MODEST SIDE...AND THIS MAY KEEP STORMS
IN CHECK...WITH AGAIN THE MAIN CONCERNS THE HEAVY RAINFALL
POTENTIAL...WITH PWAT BETWEEN 1.8 AND 2 INCHES...AND MEAN RH IN
THE 70 TO 80 PERCENT RANGE.
THE SURFACE BOUNDARY WILL WASH-OUT BY WEDNESDAY...AND WEAK FLAT
UPPER LEVEL RIDGING WILL TRY TO BUILD INTO THE FORECAST AREA.
STILL...PLENTY OF MOISTURE WITH SOUTH FLOW OFF THE GULF. MAIN
KICKER WILL BE DAYTIME HEATING...SO WILL HAVE TYPICAL SUMMERTIME
CONVECTION TYPE POPS FOR THE REMAINDER OF THE FORECAST TO COVER
DIURNAL DRIVEN STORMS.
RUA
MARINE...
MODERATE SOUTHEAST FLOW OCCURRING OVER THE COASTAL WATERS THIS
EARLY MORNING WITH NOCTURNAL LOW LEVEL JET AND INFLOW INTO TROUGH
AND COMPLEX OF STORMS OVER THE RED RIVER VALLEY INTO CENTRAL
TEXAS. SUSTAINED WINDS AT TIMES NEAR 20 KNOTS...AND PROGS SHOW
THIS CONTINUING THROUGH THE MORNING HOURS...UNTIL TROUGH GETS
CLOSER TO THE REGION. THEREFORE...WILL EXTEND SMALL CRAFT EXERCISE
CAUTION THROUGH THE MORNING HOURS.
WINDS AWAY FROM CONVECTION WILL DECREASE LATER THIS AFTERNOON INTO
MONDAY AS SURFACE TROUGH NEARS THE FORECAST AREA...LESSENING THE
GRADIENT ACROSS THE COASTAL WATERS. THIS SURFACE TROUGH WILL STALL
AND WASH OUT NORTH OF THE COASTAL WATERS LATE MONDAY INTO TUESDAY.
THEREFORE...WITH HIGH PRESSURE AT THE SURFACE ANCHORED OFF THE
SOUTHEAST U.S. COAST...SOUTH TO SOUTHEAST WINDS WILL PREVAIL AT
LIGHT TO OCCASIONALLY MODERATE LEVELS THROUGH THE FORECAST PERIOD.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE LATER TODAY AND
MONDAY...WITH UNSTABLE CONDITIONS PREVAILING INTO TUESDAY...AS THE
TROUGH INTERACTS WITH THE MOIST ENVIRONMENT TO PRODUCE SCATTERED
SHOWERS AND THUNDERSTORMS...ESPECIALLY NEAR SHORE OR OVER THE
COASTAL LAKES. WINDS AND SEAS WILL BE LOCALLY HIGHER NEAR THE
STORMS. THE CONVECTION WILL DECREASE IN COVERAGE FOR THE MIDDLE TO
LATE PART OF THE WEEK.
RUA
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 88 73 85 70 / 50 20 60 40
LCH 87 76 87 74 / 30 20 40 20
LFT 87 75 87 73 / 30 20 50 30
BPT 86 76 88 74 / 30 20 40 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL NOON CDT TODAY FOR GMZ450-452-
455-470-472-475.
&&
$$
PUBLIC...07
AVIATION...24
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1129 AM EDT SUN MAY 17 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 315 AM EDT SUN MAY 17 2015
A WARM FRONT WILL LIFT NORTH TODAY PUTTING SOUTHERN LOWER MICHIGAN
IN AN INCREASINGLY WARM AND HUMID AIRMASS. AN ISOLATED SHOWER OR
STORM IS POSSIBLE TODAY WITH A MUCH BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON AND EVENING. A STRONG COLD
FRONT WILL MOVE THROUGH MONDAY BRINGING A CONTINUED CHANCE FOR A
SHOWER OR THUNDERSTORM. MUCH COOLER WEATHER WILL MOVE IN TUESDAY
THROUGH MIDWEEK.
&&
.UPDATE...
ISSUED AT 1129 AM EDT SUN MAY 17 2015
I CURRENTLY REMAIN UNIMPRESSED ON THE CHANCE OF SEVERE STORMS
LATE THIS AFTERNOON AND THIS EVENING. THE RAP AND NAM FROM THE
LATEST MODEL RUNS HAVE TO CORE OF THE LOW LEVEL JET GOING OVER
NORTHERN LAKE MICHIGAN INTO THE UPPER PENINSULA BETWEEN 4 PM AND
MIDNIGHT. THAT PUTS SOUTHWEST MICHIGAN IN THE SPEED DIVERGENCE
AREA OF THE LOW LEVEL JET (NOT GOOD FOR SEVERE STORMS). THE UPPER
DIVERGENCE FROM THE UPPER LEVEL JET CORE IS OVER THE LOW LEVEL
JET MAX (NORTHERN WISCONSIN) THIS AFTERNOON AND EVENING...NOT
OVER SOUTHWEST MICHIGAN. THE DEEP LAYER SHEAR GREATER THAN 35
KNOTS IS MOSTLY WEST OF US-131 AND NORTH OF MKG THIS AFTERNOON AND
EVENING...REALLY IT IS OVER WISCONSIN (40 TO 60 KNOTS). THE SPC
ENSEMBLE 09Z HAS THE 30 TO 40 PERCENT CHANCE FOR SEVERE STORMS
OVER WISCONSIN THIS AFTERNOON AND EVENING...MEANWHILE A 10 PERCENT
AREA DOES GET INTO WESTERN LOWER MICHIGAN WEST OF US-131 FROM 4 PM
TILL 8 PM. ALL OF THIS TELL ME THE RISK FOR SEVERE STORMS OVER
SOUTHWEST MICHIGAN WOULD BE VERY LOW. STILL IT IS NOT ZERO SO WE
WILL HAVE TO WATCH AS CONDITIONS DEVELOP THIS AFTERNOON AND
EVENING.
OVERALL OUR BEST CHANCE FOR THUNDERSTORMS IS THIS EVENING. I HAVE
NOT SIGNIFICANTLY CHANGED OUR FORECAST IN THAT WAY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 315 AM EDT SUN MAY 17 2015
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
PROBABILITIES FOR CONVECTION TODAY THROUGH MONDAY.
THE AIRMASS OVER OUR FCST AREA WILL BECOME INCREASINGLY WARM AND
HUMID TODAY AS A WARM FRONT GRADUALLY MOVES NORTH OF OUR AREA.
THERE IS JUST A SMALL CHANCE OF AN ISOLATED SHOWER OR THUNDERSTORM
BUT MOST OF OUR AREA WILL STAY DRY THIS MORNING THROUGH MOST OF
THE AFTERNOON.
00Z 4KM WRF-NMM SIM Z GUIDANCE AND THE NSSL WRF SUGGEST THAT
SHOWERS AND THUNDERSTORMS ARE LIKELY TO DEVELOP ACROSS OUR AREA
LATE THIS AFTERNOON THROUGH THE EVENING. CONVECTIVE DEVELOPMENT LATE
THIS AFTERNOON AND EARLY EVENING WILL BE AIDED BY WEAK TO MODERATE
INSTABILITY WITH POTENTIAL FOR SB CAPE VALUES TO REACH AROUND
1000-2000 J/KG.
SHOWERS AND STORMS LATE THIS EVENING WILL BE AIDED BY FORCING
FROM A 35 TO 40 KT LLJ AND STRONG 1000-850 MB MOISTURE TRANSPORT.
A FEW SHOWERS OR ISOLATED STORMS MAY LINGER VERY LATE TONIGHT BUT
THE MOST LIKELY TIME FRAME FOR CONVECTION SEEMS TO BE FROM AROUND
21Z THIS AFTERNOON THROUGH 06Z TONIGHT.
CONVECTIVE POTENTIAL FOR MONDAY IS LARGELY CONTINGENT ON EXACT
COLD FRONTAL TIMING. A CONSENSUS OF LATEST GUIDANCE SUGGESTS THAT
THE BETTER CHANCE FOR STORMS WILL LIKELY STAY SE OF OUR FCST
AREA... BUT THAT SOME SHOWERS AND STORMS MAY REDEVELOP MAINLY OVER
OUR SE FCST AREA PRIOR TO FROPA.
SHORT RANGE GUIDANCE CONTINUES TO SUGGEST SOME WEAK TO MODERATE
INSTABILITY WILL DEVELOP JUST AHEAD OF THE FRONT SO THIS WILL NEED
TO BE MONITORED SINCE FORCING FROM THE FRONT WILL BE STRONG.
HOWEVER IF FRONT MOVES THROUGH FASTER AS SUGGESTED BY THE 00Z GFS
THEN ALL OF OUR FCST AREA SHOULD STAY DRY MONDAY.
IT WILL TURN BREEZY BEHIND THE FRONT MONDAY NIGHT THROUGH TUESDAY
WITH STRONG NW FLOW CAA. MAX TEMPS TUESDAY WILL ONLY REACH THE
50S.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM EDT SUN MAY 17 2015
THREAT OF FROST EXISTS ON TUESDAY NIGHT AS COLD DRY AIR MASS SETTLES
INTO THE REGION FROM THE NORTH. HOWEVER THERE IS STILL SOME QUESTION
AS TO HOW QUICK THE SFC RIDGE BUILDS IN AND WHETHER OR NOT THE WINDS
DIE OFF. EXTENT OF CLEARING IS ALSO UNCERTAIN AT THIS TIME.
OTHERWISE A RATHER QUIET/UNEVENTFUL LONG TERM PERIOD EXPECTED WITH
SURFACE RIDGING AND RELATIVELY COOL DRY AIR MASS DOMINATING OUR
WEATHER. THIS PATTERN SHOULD RESULT IN A DECENT AMOUNT OF SUNSHINE
ALONG WITH LARGE DIURNAL TEMPERATURES SWINGS. EXPECT COOL NIGHTS AND
GENERALLY PLEASANT DAYS WITH LOW HUMIDITIES AND HIGHS MODERATING A
FEW DEGREES EACH DAY.
ONE THING TO WATCH HOWEVER IS THE POTENTIAL FOR CONSIDERABLE MID AND
HIGH CLOUDS AND EVEN SOME SPRINKLES ON WEDNESDAY RELATED TO A SYSTEM
PASSING BY JUST TO OUR SOUTH IN THE ZONAL FLOW. THEN...THE NORTHWEST
FLOW ALOFT ON THURSDAY AND FRIDAY COULD ALSO LEAD TO SOME BRIEF
PERIODS OF THICKER CLOUDS AND SPRINKLES AS WEAK FAST MOVING
SHORTWAVES OCCASIONALLY DROP THROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 757 AM EDT SUN MAY 17 2015
WIDESPREAD MVFR CONDITIONS ARE EXPECTED THROUGH MUCH OF TODAY
WITH LIGHT FOG/HAZE AND CIGS GENERALLY 1500-2500 FT. WHILE
SCATTERED SHOWERS ARE POSSIBLE ALL DAY TODAY...THE MAIN RISK OF
TSTMS SHOULD HOLD OFF UNTIL AFTER 21Z... POSSIBLY EVEN LATER...
LINGERING THROUGH ABOUT 04Z. CIGS LATER TODAY AND THIS EVENING MAY
BECOME PREDOMINATELY VFR...BUT WILL LIKELY TREND BACK DOWN TO MVFR
OR IFR AFTER 04Z TONIGHT. SFC WINDS WILL BE SOUTH AT 10 TO 20 KTS
TODAY AND TONIGHT.
&&
.MARINE...
ISSUED AT 315 AM EDT SUN MAY 17 2015
WE HAVE EXTENDED THE MARINE DENSE FOG ADVISORY THROUGH TONIGHT
SINCE A VERY WARM AND HUMID AIRMASS WILL CONTINUE TO ADVECT IN
OVER RELATIVELY COLD LAKE WATERS AND RESULT IN AREAS OF DENSE FOG.
SOUTHERLY WINDS WILL INCREASE SOMEWHAT THIS AFTERNOON THROUGH
TONIGHT RESULTING IN GRADUALLY INCREASING WAVE HEIGHTS. HOWEVER
WINDS AND WAVE HEIGHTS WILL STAY BELOW SMALL CRAFT CRITERIA
THROUGH TONIGHT. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS LATE
THIS AFTERNOON AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 147 PM EDT SAT MAY 16 2015
RIVER LEVELS ARE FLUCTUATING SLIGHTLY FROM THE RAIN ON FRIDAY... AND
ARE RUNNING NEAR TO BELOW NORMAL IN SOUTHERN MICHIGAN AND ABOVE
NORMAL IN WESTERN AND CENTRAL MICHIGAN. SCATTERED THUNDERSTORMS
SUNDAY AND MONDAY COULD LEAD TO LOCALLY HEAVY RAINFALL... BUT BASIN
AVERAGE RAINFALL OF A TENTH TO QUARTER INCH OVER THE NEXT COUPLE
DAYS WILL KEEP LARGER RIVER SYSTEM LEVELS UNDER CONTROL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...DENSE FOG ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1113 AM EDT SUN MAY 17 2015
.UPDATE...
FOG LIFTED INTO LOW STRATUS DURING MID MORNING AND SOME OF THE
STRATUS MIXED OUT INTO POCKETS OF CLEAR SKY DURING LATE MORNING.
THE LATEST SATELLITE TREND INDICATES THE CLEAR POCKETS QUICKLY
FILLING IN WITH SHALLOW CU OVER THE MOIST BOUNDARY LAYER HAVING
DEWPOINT GENERALLY IN THE MID 60S. EXPECT THIS WILL CONTINUE WITH
NO BETTER THAN PARTLY SUNNY/BROKEN SKY THROUGH THE REST OF THE
DAY. THE MOIST BOUNDARY LAYER ALSO MAINTAINS A STAGE FOR SCATTERED
SHOWERS/ORDINARY STORMS AS CONDITIONS WARM TO CONVECTIVE
TEMPERATURE IN THE UPPER 70S. SURFACE ANALYSIS PLACES THE WARM
FRONT MOSTLY NORTH OF OUR AREA AND ATTEMPTING TO MAKE PROGRESS
INTO THE MID LAKE HURON MARINE LAYER. THERE COULD BE SOME
SHORELINE LAKE BREEZE BOUNDARIES TO FOCUS DEVELOPMENT LEAVING WARM
SECTOR SURFACE HEATING TO MAX TEMPS IN THE LOWER 80S NEEDED FOR
DEVELOPMENT ELSEWHERE. THE BEST CHANCE OF ACTIVITY WILL ACCOMPANY
THE PRIMARY THETA-E RIDGE BUILDING IN FROM ILLINOIS AND INDIANA
DURING LATE AFTERNOON INTO THIS EVENING.
&&
.AVIATION...ISSUED 732 AM EDT SUN MAY 17 2015
LOW CLOUDS AND FOG WILL QUICKLY LIFT BETWEEN 12-16Z THIS
MORNING...RESULTING IN HIGH-END MVFR CONDITIONS BY LATE MORNING. A
WARM AND MOIST AIRMASS WILL AGAIN BRING THE THREAT FOR SHOWERS AND
THUNDERSTORMS TODAY...HOWEVER COVERAGE AND TIMING ARE VERY UNCERTAIN
WITH A LACK OF STRONG FOCUSING MECHANISM AND ONLY WEAK INSTABILITY.
A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL THEN EXIST
OVERNIGHT...ESPECIALLY FROM FNT NORTH...AS THE REMNANTS OF A COLD
FRONT MOVE ACROSS THE AREA.
FOR DTW...FOG AND LOW CEILINGS WILL LIFT THROUGH THE MORNING AS
SOUTH-SOUTHEAST WINDS BEGIN TO INCREASE. SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE TODAY...HOWEVER TIMING AND COVERAGE ARE TOO
UNCERTAIN AT THIS TIME TO HIGHLIGHT IN TAFS.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CIG BELOW 5000 FEET THROUGH 00Z.
* LOW FOR A THUNDERSTORM TODAY AND TONIGHT.
* LOW FOR VISIBILITY BELOW 1/2SM AND CIGS BELOW 200 FEET AFTER 12Z
THIS MORNING.
&&
.PREV DISCUSSION...ISSUED 359 AM EDT SUN MAY 17 2015
SHORT TERM...TODAY AND TONIGHT
LIGHT WINDS...BREAKS IN THE CLOUDS...AND RAINFALL YESTERDAY HAVE ALL
SET THE STAGE FOR FOG AND STRATUS TO FORM ONCE AGAIN THIS MORNING.
SO FAR VISIBILITIES HAVE PREDOMINANTLY RANGED FROM 1-5 MILES. THE
ARRIVAL OF ADDITIONAL CLOUDS SHOULD HELP PREVENT WIDESPREAD DENSE
FOG...BUT PATCHES ARE CERTAINLY POSSIBLE. WILL CONTINUE TO MONITOR
DENSE FOG POTENTIAL THROUGH THE MORNING HOURS HOWEVER.
UPPER RIDGE STILL REMAINS OVER THE SOUTHEAST CONUS...WITH LOWER
MICHIGAN POSITIONED ON THE WESTERN PERIPHERY. THE RIDGE AXIS WILL
SHIFT EAST TODAY AS THE LARGE UPPER TROUGH OVER THE CENTRAL U.S.
BEGINS TO LIFT TOWARDS THE UPPER MIDWEST. THE INFLUENCE OF THE RIDGE
WILL CONTINUE TO PROVIDE A STABILIZING INFLUENCE OVER THE AREA
THROUGH THE MORNING HOURS...WITH THERMAL PROFILES ON GFS/NAM
FORECAST SOUNDINGS STILL SHOWING WEAK LAPSE RATES IN THE MID-LEVELS
ASSOCIATED WITH THE WARMER AIR ALOFT. POTENTIAL FOR CONVECTION
THROUGH THE EARLY PART OF THE DAY LOOKS LIMITED THEREFORE...BUT
STILL POSSIBLE ALONG A FEW FEATURES. FRONTAL BOUNDARY REMAINS DRAPED
ACROSS CENTRAL LOWER MICHIGAN AS OF 300 AM THIS MORNING. THIS FRONT
WILL LIFT NORTHWARD THROUGH THE LATE MORNING AS SOUTHERLY FLOW
INCREASES AHEAD OF THE APPROACHING UPPER TROUGH. THE FRONT COULD
PROVIDE A FOCUS THIS MORNING FOR A FEW SHOWERS OR EVEN A TSTORM TO
FORM OVER THE SAGINAW VALLEY AND THUMB. FURTHER SOUTH IN THE WARM
SECTOR...UPPER SHORTWAVE MOVING EAST THROUGH THE OHIO VALLEY COULD
TRIGGER A FEW SHOWERS/TSTORMS NEAR THE BORDER.
AIRMASS WILL REMAIN VERY MOIST TODAY/TONIGHT WITH DEWPOINTS IN THE
60S. TEMPERATURES IN THE MID-LEVELS WILL MEANWHILE COOL SLIGHTLY
THROUGH THE DAY AS THE UPPER RIDGE AXIS PULLS EAST...WHILE THE
SURFACE LAYER HEATS TO AROUND 80F THIS AFTERNOON. AS THIS
OCCURS...WILL SEE INSTABILITY INCREASE THROUGH THE DAY AND BECOME
SURFACE BASED...WITH A PARCEL OF 80/65 YIELDING ABOUT 1000 J/KG OF
CAPE DURING THE LATE AFTERNOON. SEVERE WEATHER IS NOT EXPECTED
THROUGH LATE AFTERNOON AS SHEAR VALUES LOOK UNIMPRESSIVE AND CAPE
LOOKS TALL/SKINNY. VERY HEAVY DOWNPOURS WILL CONTINUE TO BE POSSIBLE
AS PW VALUES RISE FROM 1.5 INCHES THIS MORNING TO AROUND 1.75 INCHES
TONIGHT. WILL NEED TO FIND A TRIGGER FOR CONVECTION IN THE WARM
SECTOR TODAY/TONIGHT IN ORDER TO GET ANYTHING OTHER THAN JUST A FEW
CELLS POPPING UP HOWEVER. LOOKING BACK AT OBSERVATIONAL AND MODEL
DATA OVER THE CONUS FROM YESTERDAY...IT APPEARS AN OLD WARM FRONT
WAS CAST OFF THE SYSTEM OVER THE SOUTHERN/CENTRAL PLAINS EARLY
YESTERDAY. CURRENT OBSERVATIONS OVER SOUTEHRN ILLINOIS/INDIANA DO
INDICATE A SLIGHT "KINK" IN THE FLOW. THIS IS WHERE NAM/GFS MODELS
CURRENTLY PLACE THIS FEATURE...AND THEY BOTH LIFT IT THROUGH
SOUTHEAST MICHIGAN BETWEEN 14-22Z (PER THERMAL FIELDS AND HIGHER
THETA-E ADVECTION). COVERAGE OF SHOWERS/TSTORMS THAT COULD DEVELOP
AS THIS SUBTLE FEATURE WORKS THROUGH IS UNCERTAIN HOWEVER AS THE
ATMOSPHERE REMAINS JUICY BUT NOT OVERLY BUOYANT. KEPT COVERAGE AT
CHANCE AS HIGHER-RES RUNS OF THE 4KM WRF AND THE HRRR DO NOT SEEM
TOO KEEN ON WIDESPREAD CONVECTION DEVELOPING UNDER THE MORE STABLE
INFLUENCE OF THE RIDGE DEPARTING TO OUR EAST.
WHILE THE MAIN COLD FRONT FROM THIS SYSTEM WILL NOT PUSH THROUGH THE
AREA UNTIL MONDAY NIGHT...WHAT IS LEFT OF THE WEAKENING FRONT NOW
EXTENDING FROM MINNESOTA DOWN INTO TEXAS WILL WORK EAST ACROSS LOWER
MICHIGAN TONIGHT. THIS SHOULD PROVIDE A BETTER FOCUS FOR
SHOWERS/TSTORMS. HIGHER RES RUNS CONTINUE TO SHOW THE CURRENT LINE
OF CONVECTION BREAKING...WITH MOST OF THE ACTIVITY LIFTING TO OUR
WEST AND NORTH...ONLY CLIPPING THE SAGINAW VALLEY. STILL...BETTER
INSTABILITY ARRIVING OVERNIGHT (ELEVATED) WARRANTS CHANCE-LIKELY
POPS AS IT WORKS THROUGH.
LONG TERM...MONDAY THROUGH SATURDAY
DEEP LAYER SOUTHWESTERLY FLOW FIRMLY IN PLACE ON MONDAY WITH THE
REGION STILL LARGELY OUTSIDE THE MAIN HEIGHT FALL CENTER AND
ASSOCIATED UPPER JET CORE ATTENDANT TO THE CLOSED LOW MEANDERING
ACROSS NORTHERN MN. LEAD TROUGH AXIS TRANSLATING THROUGH TONIGHT
WILL SHUNT THE DEEPEST MOISTURE PLUME TO THE EAST BY MONDAY MORNING.
THE OVERALL REDUCTION IN MOISTURE QUALITY AND LACK OF AN APPARENT/
NECESSARY FORCING MECHANISM WITHIN THIS WELL MIXED WARM SECTOR
ENVIRONMENT WILL CONTAIN CONVECTIVE CHANCES PRIOR TO THE COLD
FRONTAL ARRIVAL. ANY EARLY DAY LOW CLOUD DEBRIS WILL MIX OUT...
INCREASING THE LIKELIHOOD FOR SEEING A GOOD BIT OF SUN BY THE MIDDAY
PERIOD. A SOLID LOOKING DIURNAL TEMPERATURE RESPONSE WITH HIGHS
MAKING A RUN INTO THE LOWER AND MIDDLE 80S.
COLD FRONTAL TIMING CENTERING ON THE 21Z-03Z PERIOD MONDAY
EVENING...AN ARRIVAL TIME CERTAINLY FAVORABLE TOWARD CAPITALIZING ON
THE BACK END OF PEAK HEATING. EXISTING ENVIRONMENT LIKELY CARRYING
MLCAPE IN THE BALLPARK OF 1500 J/KG. THIN RIBBON OF HIGHER THETA-E
ANCHORED ON THE BOUNDARY WILL HELP AUGMENT THIS DESTABILIZATION.
THE OVERALL FRONTAL POSITIONING AND TIMING WILL LEAVE A NARROW
WINDOW FOR CONVECTIVE INITIATION TO COMMENCE LOCALLY DURING THE
EVENING...ROUGHLY SOUTHEAST OF A HOWELL TO LAPEER LINE. WHILE THE
STRONGER MID LEVEL WIND FIELD WILL RESIDE BEHIND THE FRONT...SOME
INCREASE IN DEEP LAYER SHEAR WILL OCCUR JUST AS THE FRONT ARRIVES.
MID LEVEL LAPSE RATES REMAIN MODEST...BUT GIVEN THE UNDERLYING LOW
LEVEL THERMODYNAMICS...POTENTIAL WILL EXIST FOR BETTER ORGANIZED
CELLS TO EMERGE WITH AN ACCOMPANYING ISOLATED SEVERE T-STORM RISK.
ENSUING POST-FRONTAL COLD AIR ADVECTION INCREASES HEADING INTO
TUESDAY...WITH 850 MB TEMPERATURES DROPPING A GOOD 15-20 DEGREES IN
24 HOURS. THIS WILL LIKELY TRANSLATE INTO A BROAD STRATOCU FIELD
FOR TUESDAY...WITH TEMPERATURES STRUGGLING TO REACH MUCH ABOVE THE
60 DEGREE MARK. DRY/STABLE PROFILE IN PLACE THROUGH THE MIDWEEK
PERIOD...CONDITIONS DEFINED BY LOW LEVEL ANTICYCLONIC FLOW TUCKED
BENEATH A WEAKLY CONFLUENT WEST-NORTHWEST MID LEVEL PATTERN.
SEASONABLY COOL AIR MASS LEFT TO RESPOND VIA A HIGHER DEGREE OF
INSOLATION ON WEDNESDAY...NO REAL ADVECTIVE COMPONENT IN PLACE.
SLOW MODERATION OF THIS ENVIRONMENT BY THURSDAY/FRIDAY AS UPPER
HEIGHTS START TO REBOUND.
MARINE...
FAVORABLE MARINE CONDITIONS IN TERMS OF WINDS AND WAVES TO FINISH
THE WEEKEND. THE WARM AND INCREASINGLY HUMID CONDITIONS UNDER LIGHT
WIND WILL CONTINUE TO SUPPORT FOG OVER LAKE HURON THROUGH THE
MORNING HOURS. A MARINE DENSE FOG ADVISORY REMAINS IN EFFECT SOUTH
OF SAGINAW BAY. THIS ENVIRONMENT WILL REMAIN FAVORABLE FOR THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. MODEST
SOUTHWESTERLY WINDS DEVELOP IN ADVANCE OF A COLD FRONT ON MONDAY.
COLD FRONT SWEEPS THROUGH MONDAY EVENING WITH COOLER AND DRIER
CONDITIONS DEVELOPING ON WEST TO NORTHWEST FLOW FOR THE MID WEEK
PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...DENSE FOG ADVISORY UNTIL 4 AM EDT MONDAY FOR LHZ421-422-441>443-
462>464.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......BT
AVIATION.....HLO
SHORT TERM...HLO
LONG TERM....MR
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
759 AM EDT SUN MAY 17 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM EDT SUN MAY 17 2015
WATER VAPOR LOOP AND RAP ANALYSIS REVEALS WELL-DEFINED SHORTWAVE
LIFTING NORTH THROUGH THE CENTRAL PLAINS WITH PLUME OF DEEP GULF
MOISTURE STREAMING NORTH AHEAD OF IT. SFC ANALYSIS SHOWS DEWPOINTS
REACHING INTO THE LOWER 60S AS FAR NORTH AS HAYWARD AND SIREN WI.
LOWERING HEIGHT FALLS AHEAD OF THE APPROACHING SHORTWAVE COMBINED
WITH THE DEEPENING MOISTURE AND BUILDING INSTABILITY WILL PROVIDE
THE FOCUS FOR SHRA/TSRA OVER NW WI INTO UPPER MI LATER THIS
AFTERNOON INTO THIS EVENING.
TODAY AND TONIGHT...MODELS SHOW APPROACHING SHORTWAVE LIFTING NE
FROM THE CENTRAL PLAINS INTO THE UPPER LAKES BY THIS EVENING. THIS
WAVE SHOULD SPREAD SHRA/TSRA INTO THE AREA THIS AFTN AND EVENING AS
40-50 KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN
1.5 INCHES TRANSLATES E. MODEL FCST DEEP LAYER SHEAR OF 40 TO 45 KTS
COULD SUPPORT WELL ORGANIZED STRONG STORMS AND ENHANCE SEVERE TSTM
RISK. HOWEVER...AMOUNT OF INSTABILITY REMAINS IN QUESTION AS
INCREASING CLOUD COVER AHEAD OF THE SHORTWAVE COULD SUPRESS
INSTABILITY. THE GFS...CANADIAN AND RAP MODELS INDICATE MLCAPE
VALUES OF 400-800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON
COUNTIES BY THIS EVENING (00Z MON) AS NEW SPC DAY1 CONVECTIVE
OUTLOOK CONTINUES TO TARGET THESE COUNTIES AS WELL AS OTHER AREAS
ALONG THE WI BORDER FOR A SLIGHT RISK OF SVR STORMS THIS AFTERNOON
INTO THIS EVENING. THE MAIN THREATS FOR ISOLD SEVERE STORMS WOULD BE
LARGE HAIL AND DAMAGING WINDS. HIGH TEMPS WELL INTO THE 70S WILL BE
COMMON OVER THE W HALF OF THE FCST AREA TODAY WITH PERHAPS A FEW
LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE MICHIGAN
SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH COOLER
(AROUND 60F) ALONG SHORELINE.
EXPECT DIMINISHING SHRA/TSRA TO SPREAD E THRU THE EVENING AS
INSTABILITY WANES...AND THEN MOST OF THE AREA WILL PROBABLY BE DRY
OVERNIGHT. FOG COULD BECOME WIDESPREAD AND POSSIBLY DENSE LATER
TONIGHT OVER THE EAST HALF WITH ADDED MOISTURE FM DEPARTING SHRA AND
CONTINUED MOIST SSW FLOW OFF LAKE MICHIGAN. COULD ALSO BE SOME
UPSLOPE DZ INTO ERN ZONES LATE TONIGHT INTO MON MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 407 AM EDT SUN MAY 17 2015
AS HAS BEEN TALKED ABOUT FOR SEVERAL DAYS...SPLIT FLOW WILL PERSIST
ACROSS THE CONTINENT FOR THE FORESEEABLE FUTURE...WITH STRONG
POSITIVE HEIGHT ANOMALIES ACROSS NW CANADA. THIS SHOULD KEEP THE
UPPER GREAT LAKES IN STRONGLY CONFLUENT FLOW FOR MUCH OF THE
FORECAST PERIOD BEYOND TUESDAY...YIELDING A DRY FORECAST INTO
MEMORIAL DAY WEEKEND.
AS FOR MONDAY...THE NWP ARE IN GOOD AGREEMENT IN SHOWING THE
OCCLUDED FRONT MOVING ACROSS THE AREA DURING THE MORNING HOURS. WITH
THE AREA BEING IN THE DRY SLOT IN THE MORNING AND STRONG
MID LEVEL Q-VECTOR DIVERGENCE...EXPECT ANY PRECIPITATION TO BE
CONFINED TO NEAR LAKE MICHIGAN WHERE MOIST ONSHORE FLOW WILL KEEP
CHANCES OF DRIZZLE/FOG IN THE MORNING HOURS BEFORE THE WINDS TURN
WESTERLY. BEHIND THE FRONT...COMMA HEAD MOISTURE WILL ATTEMPT TO
WRAP INTO THE AREA...BUT THE DEEPER MOISTURE WILL REMAIN OVER FAR
WESTERN LAKE SUPERIOR INTO MINNESOTA UNTIL LATE IN THE DAY INTO THE
OVERNIGHT HOURS. COULD BE A PASSING SHOWER MONDAY AFTERNOON ACROSS
THE WEST AND KEWEENAW AS THE DEEPER MOISTURE WRAPS IN BEHIND THE
FILLING AREA OF LOW PRESSURE AND INCREASING UPSLOPE FLOW DUE TO NW
WINDS. STRONG COLD ADVECTION AS THE UPPER TROUGH MOVES EAST OF THE
AREA WILL ALLOW FOR 850MB TEMPS TO DROP TO -9C ACROSS MUCH OF THE
AREA. THIS COMBINED WITH NW FLOW WILL ALLOW FOR ANY RAIN SHOWERS TO
CHANGE TO SNOW AND PERHAPS INCREASE IN AREAL COVERAGE ACROSS THE
WESTERN PART OF UPPER MICHIGAN. DUE TO THE COLD TEMPERATURES AND
PRECIPITATION OCCURING DURING THE OVERNIGHT HOURS...COULD NOT
TOTALLY RULE OUT A DUSTING TO LOCALLY AN INCH OVER GRASSY AREAS
MONDAY NIGHT INTO TUESDAY MORNING BUT GIVEN THE LACK OF SIGNIFICANT
SYNOPTIC SUPPORT DUE TO THE BEST UPPER ENERGY REMAINING WEST AND
NORTH OF THE AREA...DO NOT EXPECT ANY MORE THAN THAT AT THIS TIME.
COLD AND WINDY DAY ON TUESDAY WITH DRYING ACROSS THE ENTIRE AREA
LIKELY CAUSING ANY PRECIPITATION NEAR LAKE SUPERIOR TO SUBSIDE
DURING THE AFTERNOON HOURS. STILL...IT WILL BE QUITE RAW WITH
TEMPERATURES 15-20 DEGREES BELOW NORMAL.
HEIGHTS BEGIN TO RISE ON WEDNESDAY AS THE UPPER RIDGE OVER THE
WRN ATLC BREAKS DOWN SLIGHTLY...ALLOWING THE LONG WAVE TROUGH OVER
THE REGION TO SHIFT EAST. THIS WILL ALLOW FOR SOME MODEST WARMING AT
850MB TO +4C BY WED EVENING ...WHICH COMBINED WITH THE SUNSHINE
SHOULD ALLOW FOR TEMPS TO GET AT LEAST INTO THE 50S OR LOWER 60S ON
WEDNESDAY....BUT STILL BELOW NORMAL FOR THIS TIME OF YEAR. CONTINUED
WARMING ON THURSDAY AHEAD OF AN UPPER DISTURBANCE ROTATING AROUND
THE UPPER LOW OVER NW QUEBEC. THE GFS AND ECMWF SUGGEST THIS UPPER
DISTURBANCE WILL CLIP THE UPPER GREAT LAKES THU NIGHT...HOWEVER
GIVEN THE VERY DRY AIRMASS IN PLACE ACROSS THE REGION NO
PRECIPITATION IS EXPECTED. WILL GO WITH SLIGHTLY COOLER TEMPS FRIDAY
AS 850MB TEMPS DROP BACK TO -1C. WARMER ON SATURDAY AND STILL DRY AS
HEIGHTS RISE ONCE AGAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 747 AM EDT SUN MAY 17 2015
LOW IFR/LIFR STRATUS DEVELOPED THIS MORNING AT THE TAF SITES WITH
INCREASING MOISTURE AHEAD OF AN APPROACHING LOW PRES SYSTEM. SOME
PATCHY FOG ALSO FORMED...ESPECIALLY AT SAW WITH IFR CONDITIONS IN
UPSLOPE FLOW OFF LAKE MICHIGAN. LOW CEILINGS SHOULD MIX OUT AT CMX
AND MAYBE EVEN IWD DURING THE DAY TOMORROW BUT PERSISTENT UPSLOPE
FLOW WILL KEEP LOW CLOUDS AT SAW FOR MUCH OF THE DAY. SHOWER AND
ISOLATED THUNDER CHANCES WILL INCREASE FROM WEST TO EAST THROUGH THE
DAY. EXPECT GENERALLY IMPROVING CONDITIONS LATE THIS EVENING AND
OVERNIGHT AS SHRA EXIT EAST OF THE AREA. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 519 AM EDT SUN MAY 17 2015
LOW PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY
INCREASING E TO SE FLOW TODAY. GUSTS COULD REACH AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS CENTRAL AND EAST. WARM AND MOIST AIR
SURGING NORTH AHEAD OF THE LOW WILL KEEP FOG IN THE FORECAST THROUGH
AT LEAST MONDAY MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS
OUT THE FOG. FOG COULD GET DENSE LATER TONIGHT INTO MONDAY MORNING
OVER THE EAST HALF OF THE LAKE WITH ADDED MOISTENING FROM SHRA
MOVING ACROSS AREA. THE LOW WILL CROSS LAKE SUPERIOR MONDAY AND
MONDAY EVENING. THIS WILL USHER IN NW TO NNW WINDS OF 20 TO 30 KTS
MONDAY NIGHT AND TUESDAY...MAINLY NCNTRL AND EAST HALF. BROAD HIGH
PRESSURE WILL THEN BUILD ACROSS THE REGION WEDNESDAY THROUGH
FRIDAY...BRINGING WINDS DOWN BLO 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...MRD
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
732 AM EDT SUN MAY 17 2015
.AVIATION...
LOW CLOUDS AND FOG WILL QUICKLY LIFT BETWEEN 12-16Z THIS
MORNING...RESULTING IN HIGH-END MVFR CONDITIONS BY LATE MORNING. A
WARM AND MOIST AIRMASS WILL AGAIN BRING THE THREAT FOR SHOWERS AND
THUNDERSTORMS TODAY...HOWEVER COVERAGE AND TIMING ARE VERY UNCERTAIN
WITH A LACK OF STRONG FOCUSING MECHANISM AND ONLY WEAK INSTABILITY.
A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL THEN EXIST
OVERNIGHT...ESPECIALLY FROM FNT NORTH...AS THE REMNANTS OF A COLD
FRONT MOVE ACROSS THE AREA.
FOR DTW...FOG AND LOW CEILINGS WILL LIFT THROUGH THE MORNING AS
SOUTH-SOUTHEAST WINDS BEGIN TO INCREASE. SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE TODAY...HOWEVER TIMING AND COVERAGE ARE TOO
UNCERTAIN AT THIS TIME TO HIGHLIGHT IN TAFS.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CIG BELOW 5000 FEET THROUGH 00Z.
* LOW FOR A THUNDERSTORM TODAY AND TONIGHT.
* LOW FOR VISIBILITY BELOW 1/2SM AND CIGS BELOW 200 FEET AFTER 12Z
THIS MORNING.
&&
.PREV DISCUSSION...ISSUED 359 AM EDT SUN MAY 17 2015
SHORT TERM...TODAY AND TONIGHT
LIGHT WINDS...BREAKS IN THE CLOUDS...AND RAINFALL YESTERDAY HAVE ALL
SET THE STAGE FOR FOG AND STRATUS TO FORM ONCE AGAIN THIS MORNING.
SO FAR VISIBILITIES HAVE PREDOMINANTLY RANGED FROM 1-5 MILES. THE
ARRIVAL OF ADDITIONAL CLOUDS SHOULD HELP PREVENT WIDESPREAD DENSE
FOG...BUT PATCHES ARE CERTAINLY POSSIBLE. WILL CONTINUE TO MONITOR
DENSE FOG POTENTIAL THROUGH THE MORNING HOURS HOWEVER.
UPPER RIDGE STILL REMAINS OVER THE SOUTHEAST CONUS...WITH LOWER
MICHIGAN POSITIONED ON THE WESTERN PERIPHERY. THE RIDGE AXIS WILL
SHIFT EAST TODAY AS THE LARGE UPPER TROUGH OVER THE CENTRAL U.S.
BEGINS TO LIFT TOWARDS THE UPPER MIDWEST. THE INFLUENCE OF THE RIDGE
WILL CONTINUE TO PROVIDE A STABILIZING INFLUENCE OVER THE AREA
THROUGH THE MORNING HOURS...WITH THERMAL PROFILES ON GFS/NAM
FORECAST SOUNDINGS STILL SHOWING WEAK LAPSE RATES IN THE MID-LEVELS
ASSOCIATED WITH THE WARMER AIR ALOFT. POTENTIAL FOR CONVECTION
THROUGH THE EARLY PART OF THE DAY LOOKS LIMITED THEREFORE...BUT
STILL POSSIBLE ALONG A FEW FEATURES. FRONTAL BOUNDARY REMAINS DRAPED
ACROSS CENTRAL LOWER MICHIGAN AS OF 300 AM THIS MORNING. THIS FRONT
WILL LIFT NORTHWARD THROUGH THE LATE MORNING AS SOUTHERLY FLOW
INCREASES AHEAD OF THE APPROACHING UPPER TROUGH. THE FRONT COULD
PROVIDE A FOCUS THIS MORNING FOR A FEW SHOWERS OR EVEN A TSTORM TO
FORM OVER THE SAGINAW VALLEY AND THUMB. FURTHER SOUTH IN THE WARM
SECTOR...UPPER SHORTWAVE MOVING EAST THROUGH THE OHIO VALLEY COULD
TRIGGER A FEW SHOWERS/TSTORMS NEAR THE BORDER.
AIRMASS WILL REMAIN VERY MOIST TODAY/TONIGHT WITH DEWPOINTS IN THE
60S. TEMPERATURES IN THE MID-LEVELS WILL MEANWHILE COOL SLIGHTLY
THROUGH THE DAY AS THE UPPER RIDGE AXIS PULLS EAST...WHILE THE
SURFACE LAYER HEATS TO AROUND 80F THIS AFTERNOON. AS THIS
OCCURS...WILL SEE INSTABILITY INCREASE THROUGH THE DAY AND BECOME
SURFACE BASED...WITH A PARCEL OF 80/65 YIELDING ABOUT 1000 J/KG OF
CAPE DURING THE LATE AFTERNOON. SEVERE WEATHER IS NOT EXPECTED
THROUGH LATE AFTERNOON AS SHEAR VALUES LOOK UNIMPRESSIVE AND CAPE
LOOKS TALL/SKINNY. VERY HEAVY DOWNPOURS WILL CONTINUE TO BE POSSIBLE
AS PW VALUES RISE FROM 1.5 INCHES THIS MORNING TO AROUND 1.75 INCHES
TONIGHT. WILL NEED TO FIND A TRIGGER FOR CONVECTION IN THE WARM
SECTOR TODAY/TONIGHT IN ORDER TO GET ANYTHING OTHER THAN JUST A FEW
CELLS POPPING UP HOWEVER. LOOKING BACK AT OBSERVATIONAL AND MODEL
DATA OVER THE CONUS FROM YESTERDAY...IT APPEARS AN OLD WARM FRONT
WAS CAST OFF THE SYSTEM OVER THE SOUTHERN/CENTRAL PLAINS EARLY
YESTERDAY. CURRENT OBSERVATIONS OVER SOUTEHRN ILLINOIS/INDIANA DO
INDICATE A SLIGHT "KINK" IN THE FLOW. THIS IS WHERE NAM/GFS MODELS
CURRENTLY PLACE THIS FEATURE...AND THEY BOTH LIFT IT THROUGH
SOUTHEAST MICHIGAN BETWEEN 14-22Z (PER THERMAL FIELDS AND HIGHER
THETA-E ADVECTION). COVERAGE OF SHOWERS/TSTORMS THAT COULD DEVELOP
AS THIS SUBTLE FEATURE WORKS THROUGH IS UNCERTAIN HOWEVER AS THE
ATMOSPHERE REMAINS JUICY BUT NOT OVERLY BUOYANT. KEPT COVERAGE AT
CHANCE AS HIGHER-RES RUNS OF THE 4KM WRF AND THE HRRR DO NOT SEEM
TOO KEEN ON WIDESPREAD CONVECTION DEVELOPING UNDER THE MORE STABLE
INFLUENCE OF THE RIDGE DEPARTING TO OUR EAST.
WHILE THE MAIN COLD FRONT FROM THIS SYSTEM WILL NOT PUSH THROUGH THE
AREA UNTIL MONDAY NIGHT...WHAT IS LEFT OF THE WEAKENING FRONT NOW
EXTENDING FROM MINNESOTA DOWN INTO TEXAS WILL WORK EAST ACROSS LOWER
MICHIGAN TONIGHT. THIS SHOULD PROVIDE A BETTER FOCUS FOR
SHOWERS/TSTORMS. HIGHER RES RUNS CONTINUE TO SHOW THE CURRENT LINE
OF CONVECTION BREAKING...WITH MOST OF THE ACTIVITY LIFTING TO OUR
WEST AND NORTH...ONLY CLIPPING THE SAGINAW VALLEY. STILL...BETTER
INSTABILITY ARRIVING OVERNIGHT (ELEVATED) WARRANTS CHANCE-LIKELY
POPS AS IT WORKS THROUGH.
LONG TERM...MONDAY THROUGH SATURDAY
DEEP LAYER SOUTHWESTERLY FLOW FIRMLY IN PLACE ON MONDAY WITH THE
REGION STILL LARGELY OUTSIDE THE MAIN HEIGHT FALL CENTER AND
ASSOCIATED UPPER JET CORE ATTENDANT TO THE CLOSED LOW MEANDERING
ACROSS NORTHERN MN. LEAD TROUGH AXIS TRANSLATING THROUGH TONIGHT
WILL SHUNT THE DEEPEST MOISTURE PLUME TO THE EAST BY MONDAY MORNING.
THE OVERALL REDUCTION IN MOISTURE QUALITY AND LACK OF AN APPARENT/
NECESSARY FORCING MECHANISM WITHIN THIS WELL MIXED WARM SECTOR
ENVIRONMENT WILL CONTAIN CONVECTIVE CHANCES PRIOR TO THE COLD
FRONTAL ARRIVAL. ANY EARLY DAY LOW CLOUD DEBRIS WILL MIX OUT...
INCREASING THE LIKELIHOOD FOR SEEING A GOOD BIT OF SUN BY THE MIDDAY
PERIOD. A SOLID LOOKING DIURNAL TEMPERATURE RESPONSE WITH HIGHS
MAKING A RUN INTO THE LOWER AND MIDDLE 80S.
COLD FRONTAL TIMING CENTERING ON THE 21Z-03Z PERIOD MONDAY
EVENING...AN ARRIVAL TIME CERTAINLY FAVORABLE TOWARD CAPITALIZING ON
THE BACK END OF PEAK HEATING. EXISTING ENVIRONMENT LIKELY CARRYING
MLCAPE IN THE BALLPARK OF 1500 J/KG. THIN RIBBON OF HIGHER THETA-E
ANCHORED ON THE BOUNDARY WILL HELP AUGMENT THIS DESTABILIZATION.
THE OVERALL FRONTAL POSITIONING AND TIMING WILL LEAVE A NARROW
WINDOW FOR CONVECTIVE INITIATION TO COMMENCE LOCALLY DURING THE
EVENING...ROUGHLY SOUTHEAST OF A HOWELL TO LAPEER LINE. WHILE THE
STRONGER MID LEVEL WIND FIELD WILL RESIDE BEHIND THE FRONT...SOME
INCREASE IN DEEP LAYER SHEAR WILL OCCUR JUST AS THE FRONT ARRIVES.
MID LEVEL LAPSE RATES REMAIN MODEST...BUT GIVEN THE UNDERLYING LOW
LEVEL THERMODYNAMICS...POTENTIAL WILL EXIST FOR BETTER ORGANIZED
CELLS TO EMERGE WITH AN ACCOMPANYING ISOLATED SEVERE T-STORM RISK.
ENSUING POST-FRONTAL COLD AIR ADVECTION INCREASES HEADING INTO
TUESDAY...WITH 850 MB TEMPERATURES DROPPING A GOOD 15-20 DEGREES IN
24 HOURS. THIS WILL LIKELY TRANSLATE INTO A BROAD STRATOCU FIELD
FOR TUESDAY...WITH TEMPERATURES STRUGGLING TO REACH MUCH ABOVE THE
60 DEGREE MARK. DRY/STABLE PROFILE IN PLACE THROUGH THE MIDWEEK
PERIOD...CONDITIONS DEFINED BY LOW LEVEL ANTICYCLONIC FLOW TUCKED
BENEATH A WEAKLY CONFLUENT WEST-NORTHWEST MID LEVEL PATTERN.
SEASONABLY COOL AIR MASS LEFT TO RESPOND VIA A HIGHER DEGREE OF
INSOLATION ON WEDNESDAY...NO REAL ADVECTIVE COMPONENT IN PLACE.
SLOW MODERATION OF THIS ENVIRONMENT BY THURSDAY/FRIDAY AS UPPER
HEIGHTS START TO REBOUND.
MARINE...
FAVORABLE MARINE CONDITIONS IN TERMS OF WINDS AND WAVES TO FINISH
THE WEEKEND. THE WARM AND INCREASINGLY HUMID CONDITIONS UNDER LIGHT
WIND WILL CONTINUE TO SUPPORT FOG OVER LAKE HURON THROUGH THE
MORNING HOURS. A MARINE DENSE FOG ADVISORY REMAINS IN EFFECT SOUTH
OF SAGINAW BAY. THIS ENVIRONMENT WILL REMAIN FAVORABLE FOR THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. MODEST
SOUTHWESTERLY WINDS DEVELOP IN ADVANCE OF A COLD FRONT ON MONDAY.
COLD FRONT SWEEPS THROUGH MONDAY EVENING WITH COOLER AND DRIER
CONDITIONS DEVELOPING ON WEST TO NORTHWEST FLOW FOR THE MID WEEK
PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LHZ441>443-462>464.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....HLO
SHORT TERM...HLO
LONG TERM....MR
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1054 AM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1052 AM CDT SUN MAY 17 2015
EVOLVING CAPE FORECAST FROM NAM AND HRRR SUGGEST THE THUNDERSTORMS
MAY BECOME MUCH LESS PREVALENT BY THIS AFTERNOON. ADJUSTED TO
SHOWERS. EXPANDED THE WIND ADVISORY WEST TO INCLUDE CENTRAL AND
NORTH CENTRAL NORTH DAKOTA.
UPDATE ISSUED AT 643 AM CDT SUN MAY 17 2015
FORECAST ON TRACK WITH ONLY A COUPLE MINOR ADJUSTMENTS TO POPS
BASED ON CURRENT RADAR TRENDS. WATER VAPOR IMAGERY SHOWS BROAD
CLOSED UPPER LOW FROM EASTERN MONTANA TO EASTERN NEBRASKA WITH
WELL DEFINED CIRCULATION MOVING INTO EASTERN SOUTH DAKOTA. THIS IS
ASSOCIATED WITH A 100KT JET STREAK THAT IS NOSING INTO
SOUTHEASTERN NORTH DAKOTA...SUPPORTING AN EXPANDING AREA OF
SHRA/TSRA. EXPECT THESE TRENDS TO CONTINUE AS UPSTREAM RADARS SHOW
WIDESPREAD SHOWERS AND THUNDERSTORMS CONTINUING TO APPROACH OUR
SOUTHEASTERN AREAS FROM SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN MAY 17 2015
CONCERNS THIS FORECAST PERIOD INCLUDE ANOTHER DAY OF HEAVY RAIN FOR
CENTRAL NORTH DAKOTA. STRONG NORTH WINDS AND WIND ADVISORY CRITERIA
EXPECTED FOR EASTERN PARTS OF CENTRAL NORTH DAKOTA. THEN
ATTENTION TURNS TO RAIN CHANGING TO SNOW THIS AFTERNOON AND
TONIGHT...WITH SNOW ACCUMULATIONS EXPECTED AND A WINTER WEATHER
ADVISORY FOR NORTH CENTRAL COUNTIES TONIGHT.
THE UPPER LEVEL LOW WAS OVER EASTERN MONTANA AND WYOMING. IT IS
FORECAST TO MOVE/DEVELOP SOUTHEAST QUICKLY THIS MORNING AS AN
INTENSE UPPER LEVEL SHORTWAVE/IMPULSE MOVES NORTHWARD FROM THE
SOUTHERN PLAINS INTO THE EASTERN DAKOTAS. THIS SHOULD BE THE ONSET
OF HEAVY RAIN OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA TODAY.
IN ADDITION TO THE RAINS THAT FELL ON SATURDAY...ANOTHER INCH OR TWO
OF RAINFALL CAN BE EXPECTED ALONG AND EAST OF A LINE FROM MINOT TO
BISMARCK...WITH 0.25 TO 1 INCH WEST OF THIS LINE.
THIS STRONG UPPER LEVEL LOW WILL BE ASSOCIATED WITH DEEPENING OF THE
SURFACE LOW THAT IS CURRENTLY CENTERED OVER CENTRAL SOUTH DAKOTA.
THIS LOW WILL STRENGTHEN AS IT MOVES NORTHEAST TOWARDS THE ND/SD/MN
BORDER BY THIS EVENING. NORTH WINDS WILL INCREASE TODAY TO 25 TO 35
MPH ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE STRONGEST WINDS OF
30 TO 35 MPH WITH GUSTS TO 45 MPH SHOULD OCCUR FROM BOTTINEAU AND
THE TURTLE MOUNTAINS SOUTHWARD ALONG THE JAMES RIVER VALLEY TO
MCINTOSH AND DICKEY COUNTIES.
THE NORTH WINDS WILL USHER IN MUCH COOLER AIR...AND RAIN WILL MIX
WITH AND CHANGE TO SNOW THIS AFTERNOON NORTHWEST AND NORTH CENTRAL.
THE CHANGEOVER TO SNOW WILL PROGRESS SOUTHEASTWARD TONIGHT AND SNOW
ACCUMULATIONS CAN BE EXPECTED OVER MUCH OF THE FORECAST AREA.
EXPECTING 3 TO 5 INCHES OVER MUCH OF THE NORTH CENTRAL...FROM
STANLEY AND KENMARE IN THE NORTHWEST...TO GARRISON...HARVEY...AND
CARRINGTON IN THE SOUTH...INCLUDING MINOT TO RUGBY AND THE TURTLE
MOUNTAINS. A WINTER WEATHER ADVISORY WILL BE ISSUED FOR THIS AREA.
LESSER AMOUNTS OF SNOW ACCUMULATION ARE EXPECTED TO THE SOUTH AND
WEST.
FREEZING TEMPERATURES IN THE MID 20S TO LOWER 30S WILL BE WIDESPREAD
ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN MAY 17 2015
MONDAY MORNING WILL SEE LINGERING RAIN/SNOW SHOWERS AS THE DEEP LOW
PRESSURE SYSTEM REACHES THE GREAT LAKES REGION BY 18Z MON. HIGH
PRESSURE WILL SETTLE OVER THE NORTHERN PLAINS BEHIND THE
LOW...LEADING TO MOSTLY DRY CONDITIONS. IN ADDITION...TEMPERATURES
WILL SHOW A WARMING TREND WITH MAX TEMPS BACK INTO THE 60S BY
MIDWEEK. THE GREATEST WEATHER IMPACT WILL BE FROM FROST/FREEZE
CONDITIONS MONDAY NIGHT AND TUESDAY NIGHT. MONDAY NIGHT IS
EXPECTED TO BE THE COLDER OF THE TWO NIGHTS WITH LOWS REACHING THE
MID 20S.
GFS/ECMWF BRING AN UPPER LOW TO WYOMING BY EARLY
WEDNESDAY...ALTHOUGH PRECIP WITH THIS SYSTEM IS CONFINED TO
LOCATIONS TO OUR SOUTH. THE NEXT CHANCE OF PRECIP WOULD THEN BE NEXT
WEEKEND WITH GFS/ECMWF/ENSEMBLES SHOWING AN UPPER LEVEL TROUGH
ACROSS THE NORTH CENTRAL CONUS WITH SURFACE LOW TRACKING OVER THE
CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 643 AM CDT SUN MAY 17 2015
MVFR AND IFR CONDITIONS IN RAIN SHOWERS AND FOG THROUGH THE
AFTERNOON FOR THE TERMINALS. THUNDERSTORMS WITH HEAVY RAIN
EXPECTED AT KJMS/KBIS/KMOT. STRONG NORTH WINDS THROUGH THE TAF
PERIOD. NORTH WINDS WILL USHER IN COLD AIR AND RAIN CHANGES TO SNOW
AT KISN/KMOT AROUND 21Z...AND AT KDIK/KBIS AROUND 00Z...AND KJMS
AROUND 02Z. MAINLY IFR CONDITIONS IN SNOW AND FOG WITH STRONG WINDS
EXPECTED TONIGHT. KISN MAY SEE IMPROVING CONDITIONS TO VFR AFT 06Z.
&&
.HYDROLOGY...
ISSUED AT 415 AM CDT SUN MAY 17 2015
ANOTHER 1 OR 2 INCHES OF RAINFALL IS EXPECTED TODAY ALONG AND EAST
OF A LINE FROM MINOT TO BISMARCK. FLOODING IN LOW LYING AND POOR
DRAINAGE AREAS IS POSSIBLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
MONDAY FOR NDZ003>005-010>013-021>023-025.
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ003>005-011>013-
021>023-025.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM CDT MONDAY FOR
NDZ036-037-046>048-050-051.
WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ MONDAY FOR NDZ019-020-
034-035-042-045.
&&
$$
UPDATE...WAA
SHORT TERM...JV
LONG TERM...JNS
AVIATION...JV
HYDROLOGY...JV
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
822 AM EDT SUN MAY 17 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST OVER THE SOUTHEAST EARLY
THIS WEEK. A COLD FRONT WILL APPROACH LATE MONDAY AND MOVE THROUGH
ON TUESDAY...BRINGING PRECIPITATION CHANCES TO BOTH THE MOUNTAINS
AND PIEDMONT. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL RETURN
WEDNESDAY. SOMEWHAT UNSETTLED WEATHER WILL RETURN LATE IN THE WEEK
WITH A STATIONARY FRONT SETTING UP OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 820 AM...REGIONAL RADAR CONTINUES TO INDICATE A FEW PATCHES
OF LIGHT RETURNS ACROSS THE WESTERN CAROLINA AND GEORGIA MTNS. I
WILL ISSUE A QUICK UPDATE TO ADJUST POP...SKY...AND TEMPS TO
LATEST TRENDS.
AS OF 650 AM EDT...EARLY RADAR RETURNS AROUND DAYBREAK ARE WRAPPING
SCATTERED SHOWERS INTO THE FAR SW MTNS. WILL BOOST POPS SLIGHTLY IN
THAT AREA...BUT THE FORECAST TRENDS REMAIN ON TRACK OTHERWISE.
THE HIGHLY AMPLIFIED UPPER FLOW PATTERN OVER THE CONUS WILL KEEP A
RIDGE IN PLACE OVER THE SE THROUGH THE NEAR TERM. PLENTY OF MID AND
HIGH DEBRIS CLOUDS WILL RIDE OVER THE RIDGE AXIS ACROSS THE
AREA...BUT WITH ENOUGH BREAKS TO PERMIT MAX TEMPS TO CLIMB TO ABOUT
5 DEGREES ABOVE CLIMO IN MOST AREAS...AND TO FOSTER A HEALTHY
CUMULUS FIELD. THE NUMERICAL MODELS KEEP THE DEEPEST MOISTURE AND
BEST FORCING FROM S TO SW UPSLOPE FLOW AND LOW LEVEL WIND
CONVERGENCE CONFINED TO THE SPINE OF THE SOUTHERN APPALACHIANS THIS
AFTERNOON AND EVENING. WRN MTN INSTABILITY WILL INCREASE THROUGH THE
DAY...WITH SBCAPE VALUES RUNNING 2000 J/KG OR GREATER BY LATE
AFTERNOON NEAR THE TN BORDER. NAM AND RAP PROFILES HAVE MUCH MORE
LIMITED INSTABILITY EAST OF THE MOUNTAINS...AND THE NAM QPF
PRESENTATION OF MAINLY MTN COVERAGE FOR LATE DAY IS PREFERRED. WILL
THUS FEATURE LIKELY POPS THIS AFTN NEAR THE TN BORDER AND TAPER DOWN
TO BELOW SLIGHT CHANCE FOR CLT METRO.
CONVECTIVE COVERAGE SHOULD WANE QUICKLY THIS EVENING...BUT WILL KEEP
ISOLD SHOWER COVERAGE GOING THROUGH THE NIGHT IN DEVELOPING LIGHT
WESTERLY UPSLOPE FLOW. MILD MINS SHOULD BE ANOTHER 1 TO 2 DEGREES
WARMER THAN THIS MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...UPPER HEIGHTS WILL FALL MONDAY OVER THE NERN
CONUS AS LOW PRESSURE MOVES ACRS THE GREAT LAKES. LATEST MODEL PROGS
SHOW LITTLE IMPACT IN THE HEIGHT FIELD OVER THE SOUTHEAST...BUT STILL
SHOW LLVL FLOW VEERING TO NWLY AS THE DAY PROGRESSES. WITHOUT GULF
FLOW ENHANCING WARM/MOIST ADVECTION THE THERMODYNAMIC CONDITIONS WILL
LIKELY BE SIMILAR TO SUNDAY...EXCEPT THAT THE WEAKER RIDGE WILL ALLOW
DEEP CONVECTION OVER THE PIEDMONT AS WELL AS OVER THE MTNS. DEEP
SHEAR REMAINS SMALL. SEVERE DOWNBURST WINDS CANNOT BE TOTALLY RULED
OUT BUT WILL LIKELY REMAIN ISOLATED. PWAT VALUES WELL ABOVE CLIMO AND
SHORT STORM MOTION VECTORS IMPLY HEAVY RAIN WILL BE A MORE LIKELY
THREAT.
AS THE LOW MOVES EWD INTO QUEBEC MON NIGHT...ITS COLD FRONT WILL
CROSS THE SRN APPALACHIANS. EAST OF THE MTNS CONVECTION SHOULD
GRADUALLY WANE WITH THE LOSS OF DIURNAL HEATING...BUT STRENGTHENING
UPSLOPE FLOW MAY ALLOW ACTIVITY TO CONTINUE OVERNIGHT NEAR THE TENN
BORDER. LATER ON TUE THE FRONT WILL PROGRESS ACRS THE CWFA. OVER THE
HIGHER TERRAIN SLIGHTLY COOLER TEMPS AND AN EARLIER THAN NORMAL PEAK
IN CONVECTIVE ACTIVITY ARE EXPECTED. THE PIEDMONT HOWEVER LOOKS TO
SEE A DAY VERY MUCH LIKE MONDAY...PERHAPS EVEN WITH BETTER COVERAGE
DUE TO FRONTAL CONVERGENCE OR MTN LEE TROUGHING. THE THREATS WILL BE
GENERALLY THE SAME.
MAX TEMPS MON/TUE WILL BE AROUND 5 DEG ABOVE CLIMO IN THE MTNS AND
NEAR 10 ABOVE IN THE PIEDMONT. CLOUD COVER WILL HELP KEEP MINS 7-10
DEG ABOVE CLIMO THROUGHOUT THE AREA...BUT TREND COOLER FROM TUE TO
WED MRNG AS THE CANADIAN AIRMASS SETTLES IN.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...HIGH PRESSURE BUILDS INTO THE OH/TN VALLEYS WED
PUSHING THE COLD FRONT THRU OUR AREA...WHICH THEN STALLS. GFS AND EC
HAVE PREVIOUSLY DIFFERED ON WHETHER THE FRONT WOULD CLEAR THE AREA
BEFORE BECOMING STATIONARY...BUT HAVE COME CLOSER IN LINE AND SUGGEST
IT WILL DO SO NEAR OUR SRN CWFA BORDER. WITH A TROUGH PERSISTING OVER
ERN CANADA....CYCLONIC UPPER FLOW WILL BE PRESENT ALOFT OVER THE CWFA
POTENTIALLY ENHANCING ANY BAROCLINIC FORCING ASSOCIATED WITH THE
BOUNDARY. A CUTOFF UPPER LOW MOVING IN FROM THE PACIFIC WILL SPIN UP
A NEW LOW OVER THE ROCKIES SATURDAY...LIFTING THE STATIONARY FRONT
NWD AGAIN. LOW CHANCES OF PRECIP RETURN THU AND PERIODICALLY CONTINUE
THRU THE WEEKEND...WITH LOW CONFIDENCE IN LIGHT OF MODEL DIFFERENCES
IN TIMING THE UPPER FEATURES WHICH INTERACT WITH THE BOUNDARY...AND
IN THE PLACEMENT OF THE BOUNDARY ITSELF...SINCE AREAS ON ITS WARM
SIDE ARE LIKELY TO SEE SOME DIURNAL CONVECTION. TEMPS COOL SLIGHTLY
BY THU...REMAINING JUST ABOVE CLIMO FOR MINS/MAXES THRU THE END OF
THE PERIOD.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
AT KCLT...MAINLY MID AND HIGH CLOUDS WILL DRIFT THROUGH THE RIDGE
AXIS TO HIGH PROVIDE HIGH LEVEL CIGS THROUGH THE PERIOD...BUT A
HEALTHY CUMULUS FIELD SHOULD DEVELOP ONCE AGAIN AROUND 5 KFT WITH
DAYTIME HEATING. THE MODEL PROFILES...ESPECIALLY THE RAP...ALSO
SUGGEST THAT A BRIEF PERIOD OF LOWER STRATUS COULD DEVELOP THROUGH
13Z...BUT THIS REMAINS ABSENT FROM THE MOS GUIDANCE. WILL CONTINUE
TO FEATURE ONLY A SCATTERED MVFR LEVEL LOWER CLOUD LAYER STARTING AT
12Z AND LASTING THROUGH MID MORNING. WARM TEMPERATURES ALOFT UNDER
THE RIDGE WILL LIMIT INSTABILITY AND LITTLE IN THE WAY OF CONVECTIVE
TRIGGERS WILL BE FOUND EAST OF THE MTNS THIS AFTN/EVENING. EXPECT
LIGHT S TO SW WINDS THROUGHOUT AT LESS THAN 10 KT.
ELSEWHERE...MAINLY ALTOCUMULUS AND CIRRUS CEILINGS ARE EXPECTED THIS
MORNING...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING WITH HEATING
TO PRODUCE SOME VFR CIGS AT 4 TO 6 KFT ACROSS THE MTNS AND FOOTHILLS
THROUGH THE DAY. THE DEEPER MOISTURE AND BEST FORCING FROM UPSLOPE
AND LOW LEVEL WIND CONVERGENCE WILL BE FOUND OVER THE WRN MTNS AND
ALONG THE RIDGE TOPS TODAY...WITH KAVL STANDING THE BEST CHANCE OF
AN AFTN/EVENING TSRA. WILL FEATURE VCSH WITH AFTN PROB30 TSRA AT
KAVL...AND PROB30 TSRA AT KHKY...BUT KEEP THE UPSTATE TAF SITES DRY
WITH MORE LIMITED INSTABILITY EXPECTED IN THE PROFILES. WINDS WILL
BE LIGHT S TO SW THROUGHOUT AT 10 KT OR LESS THROUGH THE PERIOD.
OUTLOOK...DEEPER MOISTURE WILL ARRIVE IN THE APPALACHIANS MON
THROUGH TUE AS A COLD FRONT APPROACHES FROM THE W. THE FRONT WILL
SETTLE SOUTHEAST OF THE AREA ON WEDNESDAY TO PERMIT BRIEF DRYING MID
WEEK. UNTIL THEN...DIURNAL SHOWERS AND THUNDERSTORMS WILL
FORM...WITH THE BEST COVERAGE OVER THE MTNS...WITH MORNING FOG
LIKELY IN AREAS THAT RECEIVE RAINFALL.
CONFIDENCE TABLE...
12-18Z 18-24Z 00-06Z 06-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 97% HIGH 100% HIGH 100% HIGH 91%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...NED
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
708 AM EDT SUN MAY 17 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST OVER THE SOUTHEAST EARLY
THIS WEEK. A COLD FRONT WILL APPROACH LATE MONDAY AND MOVE THROUGH
ON TUESDAY...BRINGING PRECIPITATION CHANCES TO BOTH THE MOUNTAINS
AND PIEDMONT. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL RETURN
WEDNESDAY. SOMEWHAT UNSETTLED WEATHER WILL RETURN LATE IN THE WEEK
WITH A STATIONARY FRONT SETTING UP OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 650 AM EDT...EARLY RADAR RETURNS AROUND DAYBREAK ARE WRAPPING
SCATTERED SHOWERS INTO THE FAR SW MTNS. WILL BOOST POPS SLIGHTLY IN
THAT AREA...BUT THE FORECAST TRENDS REMAIN ON TRACK OTHERWISE.
THE HIGHLY AMPLIFIED UPPER FLOW PATTERN OVER THE CONUS WILL KEEP A
RIDGE IN PLACE OVER THE SE THROUGH THE NEAR TERM. PLENTY OF MID AND
HIGH DEBRIS CLOUDS WILL RIDE OVER THE RIDGE AXIS ACROSS THE
AREA...BUT WITH ENOUGH BREAKS TO PERMIT MAX TEMPS TO CLIMB TO ABOUT
5 DEGREES ABOVE CLIMO IN MOST AREAS...AND TO FOSTER A HEALTHY
CUMULUS FIELD. THE NUMERICAL MODELS KEEP THE DEEPEST MOISTURE AND
BEST FORCING FROM S TO SW UPSLOPE FLOW AND LOW LEVEL WIND
CONVERGENCE CONFINED TO THE SPINE OF THE SOUTHERN APPALACHIANS THIS
AFTERNOON AND EVENING. WRN MTN INSTABILITY WILL INCREASE THROUGH THE
DAY...WITH SBCAPE VALUES RUNNING 2000 J/KG OR GREATER BY LATE
AFTERNOON NEAR THE TN BORDER. NAM AND RAP PROFILES HAVE MUCH MORE
LIMITED INSTABILITY EAST OF THE MOUNTAINS...AND THE NAM QPF
PRESENTATION OF MAINLY MTN COVERAGE FOR LATE DAY IS PREFERRED. WILL
THUS FEATURE LIKELY POPS THIS AFTN NEAR THE TN BORDER AND TAPER DOWN
TO BELOW SLIGHT CHANCE FOR CLT METRO.
CONVECTIVE COVERAGE SHOULD WANE QUICKLY THIS EVENING...BUT WILL KEEP
ISOLD SHOWER COVERAGE GOING THROUGH THE NIGHT IN DEVELOPING LIGHT
WESTERLY UPSLOPE FLOW. MILD MINS SHOULD BE ANOTHER 1 TO 2 DEGREES
WARMER THAN THIS MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...UPPER HEIGHTS WILL FALL MONDAY OVER THE NERN
CONUS AS LOW PRESSURE MOVES ACRS THE GREAT LAKES. LATEST MODEL PROGS
SHOW LITTLE IMPACT IN THE HEIGHT FIELD OVER THE SOUTHEAST...BUT STILL
SHOW LLVL FLOW VEERING TO NWLY AS THE DAY PROGRESSES. WITHOUT GULF
FLOW ENHANCING WARM/MOIST ADVECTION THE THERMODYNAMIC CONDITIONS WILL
LIKELY BE SIMILAR TO SUNDAY...EXCEPT THAT THE WEAKER RIDGE WILL ALLOW
DEEP CONVECTION OVER THE PIEDMONT AS WELL AS OVER THE MTNS. DEEP
SHEAR REMAINS SMALL. SEVERE DOWNBURST WINDS CANNOT BE TOTALLY RULED
OUT BUT WILL LIKELY REMAIN ISOLATED. PWAT VALUES WELL ABOVE CLIMO AND
SHORT STORM MOTION VECTORS IMPLY HEAVY RAIN WILL BE A MORE LIKELY
THREAT.
AS THE LOW MOVES EWD INTO QUEBEC MON NIGHT...ITS COLD FRONT WILL
CROSS THE SRN APPALACHIANS. EAST OF THE MTNS CONVECTION SHOULD
GRADUALLY WANE WITH THE LOSS OF DIURNAL HEATING...BUT STRENGTHENING
UPSLOPE FLOW MAY ALLOW ACTIVITY TO CONTINUE OVERNIGHT NEAR THE TENN
BORDER. LATER ON TUE THE FRONT WILL PROGRESS ACRS THE CWFA. OVER THE
HIGHER TERRAIN SLIGHTLY COOLER TEMPS AND AN EARLIER THAN NORMAL PEAK
IN CONVECTIVE ACTIVITY ARE EXPECTED. THE PIEDMONT HOWEVER LOOKS TO
SEE A DAY VERY MUCH LIKE MONDAY...PERHAPS EVEN WITH BETTER COVERAGE
DUE TO FRONTAL CONVERGENCE OR MTN LEE TROUGHING. THE THREATS WILL BE
GENERALLY THE SAME.
MAX TEMPS MON/TUE WILL BE AROUND 5 DEG ABOVE CLIMO IN THE MTNS AND
NEAR 10 ABOVE IN THE PIEDMONT. CLOUD COVER WILL HELP KEEP MINS 7-10
DEG ABOVE CLIMO THROUGHOUT THE AREA...BUT TREND COOLER FROM TUE TO
WED MRNG AS THE CANADIAN AIRMASS SETTLES IN.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...HIGH PRESSURE BUILDS INTO THE OH/TN VALLEYS WED
PUSHING THE COLD FRONT THRU OUR AREA...WHICH THEN STALLS. GFS AND EC
HAVE PREVIOUSLY DIFFERED ON WHETHER THE FRONT WOULD CLEAR THE AREA
BEFORE BECOMING STATIONARY...BUT HAVE COME CLOSER IN LINE AND SUGGEST
IT WILL DO SO NEAR OUR SRN CWFA BORDER. WITH A TROUGH PERSISTING OVER
ERN CANADA....CYCLONIC UPPER FLOW WILL BE PRESENT ALOFT OVER THE CWFA
POTENTIALLY ENHANCING ANY BAROCLINIC FORCING ASSOCIATED WITH THE
BOUNDARY. A CUTOFF UPPER LOW MOVING IN FROM THE PACIFIC WILL SPIN UP
A NEW LOW OVER THE ROCKIES SATURDAY...LIFTING THE STATIONARY FRONT
NWD AGAIN. LOW CHANCES OF PRECIP RETURN THU AND PERIODICALLY CONTINUE
THRU THE WEEKEND...WITH LOW CONFIDENCE IN LIGHT OF MODEL DIFFERENCES
IN TIMING THE UPPER FEATURES WHICH INTERACT WITH THE BOUNDARY...AND
IN THE PLACEMENT OF THE BOUNDARY ITSELF...SINCE AREAS ON ITS WARM
SIDE ARE LIKELY TO SEE SOME DIURNAL CONVECTION. TEMPS COOL SLIGHTLY
BY THU...REMAINING JUST ABOVE CLIMO FOR MINS/MAXES THRU THE END OF
THE PERIOD.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
AT KCLT...MAINLY MID AND HIGH CLOUDS WILL DRIFT THROUGH THE RIDGE
AXIS TO HIGH PROVIDE HIGH LEVEL CIGS THROUGH THE PERIOD...BUT A
HEALTHY CUMULUS FIELD SHOULD DEVELOP ONCE AGAIN AROUND 5 KFT WITH
DAYTIME HEATING. THE MODEL PROFILES...ESPECIALLY THE RAP...ALSO
SUGGEST THAT A BRIEF PERIOD OF LOWER STRATUS COULD DEVELOP THROUGH
13Z...BUT THIS REMAINS ABSENT FROM THE MOS GUIDANCE. WILL CONTINUE
TO FEATURE ONLY A SCATTERED MVFR LEVEL LOWER CLOUD LAYER STARTING AT
12Z AND LASTING THROUGH MID MORNING. WARM TEMPERATURES ALOFT UNDER
THE RIDGE WILL LIMIT INSTABILITY AND LITTLE IN THE WAY OF CONVECTIVE
TRIGGERS WILL BE FOUND EAST OF THE MTNS THIS AFTN/EVENING. EXPECT
LIGHT S TO SW WINDS THROUGHOUT AT LESS THAN 10 KT.
ELSEWHERE...MAINLY ALTOCUMULUS AND CIRRUS CEILINGS ARE EXPECTED THIS
MORNING...BUT WITH A HEALTHY CUMULUS FIELD DEVELOPING WITH HEATING
TO PRODUCE SOME VFR CIGS AT 4 TO 6 KFT ACROSS THE MTNS AND FOOTHILLS
THROUGH THE DAY. THE DEEPER MOISTURE AND BEST FORCING FROM UPSLOPE
AND LOW LEVEL WIND CONVERGENCE WILL BE FOUND OVER THE WRN MTNS AND
ALONG THE RIDGE TOPS TODAY...WITH KAVL STANDING THE BEST CHANCE OF
AN AFTN/EVENING TSRA. WILL FEATURE VCSH WITH AFTN PROB30 TSRA AT
KAVL...AND PROB30 TSRA AT KHKY...BUT KEEP THE UPSTATE TAF SITES DRY
WITH MORE LIMITED INSTABILITY EXPECTED IN THE PROFILES. WINDS WILL
BE LIGHT S TO SW THROUGHOUT AT 10 KT OR LESS THROUGH THE PERIOD.
OUTLOOK...DEEPER MOISTURE WILL ARRIVE IN THE APPALACHIANS MON
THROUGH TUE AS A COLD FRONT APPROACHES FROM THE W. THE FRONT WILL
SETTLE SOUTHEAST OF THE AREA ON WEDNESDAY TO PERMIT BRIEF DRYING MID
WEEK. UNTIL THEN...DIURNAL SHOWERS AND THUNDERSTORMS WILL
FORM...WITH THE BEST COVERAGE OVER THE MTNS...WITH MORNING FOG
LIKELY IN AREAS THAT RECEIVE RAINFALL.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
633 AM CDT SUN MAY 17 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SUN MAY 17 2015
UPPER LOW CENTER CURRENTLY LIFTING NORTH NORTHEAST ACROSS NORTH
CENTRAL NEBRASKA WILL SLOWLY TRACK THROUGH THE FORECAST AREA TODAY.
TWO AREAS OF RAIN SHOWERS WITH EMBEDDED THUNDER ARE IMPACTING THE
AREA. THE FIRST BROAD BAND AHEAD OF THE LOW IS TRACKING NORTHWARD
ACROSS OUR EASTERN COUNTIES AHEAD OF THE SURFACE AND UPPER LOW. THE
SECOND AREA OF PRECIPITATION ON THE BACK SIDE OF THE LOW ACROSS
SOUTH CENTRAL INTO EAST CENTRAL SOUTH DAKOTA IS PIVOTING IN A
GENERAL NORTHERLY DIRECTION IN ASSOCIATION WITH MID LEVEL TROWALING.
PRECIPITATION IS EXPECTED TO PERSIST THROUGH THE MORNING ACROSS
THESE AREAS...WITH DRY SLOTTING LIMITING PRECIPITATION TO MORE
SCATTERED ACTIVITY NEAR THE I29 CORRIDOR. THE HRRR AND RUC HAVE A
DECENT HANDLE IN THE TRACK AND TIMING OF PRECIPITATION...SO FOLLOWED
THESE MODELS. AS THE LOW BEGINS PULLING AWAY TO THE NORTH THIS
AFTERNOON...MUCH OF REGION WILL BE IN THE DRY SLOT...WITH ONLY
SCATTERED SHOWERS DIMINISHING FROM SOUTH TO NORTH THROUGH EARLY
EVENING. SEVERE STORMS ARE NOT EXPECTED WITH ACTIVITY TODAY.
CLOUDY SKIES...RAINFALL... AND COOLER AIR WRAPPING BEHIND THE LOW
WILL KEEP TEMPERATURES IN CHECK THIS AFTERNOON. THE MID TO UPPER 60S
ARE EXPECTED WEST OF I29 WITH THE LOW TO MID 70S TO THE EAST WHERE
THE COOLER AIRMASS WILL BE DELAYED AND A BIT MORE SUNSHINE AND DRIER
WEATHER IS EXPECTED. WINDS WILL INCREASE THROUGH THE DAY AS THE
PRESSURE GRADIENT TIGHTENS AS THE LOW LIFTS NORTH OF THE AREA.
SUSTAINED WINDS WILL BE NEAR ADVISORY LEVEL MID TO LATE
AFTERNOON...BUT RIGHT NOW IT LOOKS LIKE THEY WILL REMAIN TOO LOW FOR
HEADLINES. SKIES WILL REMAIN PARTLY TO MOSTLY CLOUDY TONIGHT WITH
MUCH COLDER TEMPERATURES FILTERING INTO THE REGION. LOWS TONIGHT
WILL BE IN THE MID 30S TO MID 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN MAY 17 2015
WINDY AND COOL STILL LOOKS GOOD FOR MONDAY. THE UPPER LOW WILL BE
FAR ENOUGH NORTHEAST TO PROVIDE LITTLE OR NO DYNAMIC SUPPORT FOR
LIGHT SHOWERS...AND WHILE THERE COULD BE A FEW SPRINKLES WITH THE
LOW CLOUDS...WILL LEAVE OUT FOR NOW. THE LOW CLOUD COVER SHOULD
DOMINATE SKIES OVER THE NORTHEAST TO EAST CENTRAL PART OF THE
FORECAST AREA WITH LESSER CLOUD COVER TO THE SOUTHWEST. TEMPERATURES
WILL BE ON THE VERY CHILLY SIDE WITH HIGHS IN THE MID 40S NORTHEAST
TO THE MID 50S SOUTH.
CLEARING SKIES MONDAY NIGHT WITH HIGH PRESSURE RIDGING INTO THE AREA
AND THIS HIGH WILL ALSO BRING DECREASING WINDS. CHILLY TEMPERATURES
MAY DROP TO FROSTY OR FREEZY LEVELS AND WIND LOOK LIGHT ENOUGH BY
EARLY TUESDAY MORNING TO ALLOW FOR FROST EXCEPT IN PART OF SOUTHWEST
MINNESOTA SO AFTER COORDINATION WILL SO MENTION.
TUESDAY LOOKS FAIRLY SUNNY WITH SOME SLOW INCREASE IN CLOUDS
SOUTHWEST. THIS SLOW CLOUD INCREASE WILL CONTINUE FROM THE SOUTHWEST
TUESDAY NIGHT INTO WEDNESDAY AS AN EJECTED WAVE FROM PACIFIC COAST
TROUGH APPROACHES FROM THE SOUTHWEST. THIS WAVE WILL BE SUPPRESSED
TO SOME DEGREE BY A NORTHWESTERLY UPPER FLOW OVER THE WESTERN GREAT
LAKES. LIGHT RAIN LIKELY SPREADING INTO THE SOUTHWEST CORNER OF THE
AREA LATE TUESDAY NIGHT MAY NOT GET TOO FAR NORTHEAST IF THIS
SUPPRESSION IS STRONG ENOUGH. FOR NOW WILL KEEP SOME MENTION OF
LIGHT RAIN CHANCE WEDNESDAY OVER THE SOUTHWEST HALF OF THE AREA. DO
NOT EXPECT MUCH RAIN IN ANY EVENT AS THE SYSTEM WILL BE STEADILY
WEAKENING WHILE BEING SUPPRESSED BETWEEN THE NORTHWESTERLY FLOW AND A
MODEST SOUTHERN PLAINS RIDGE. TEMPERATURES WILL STILL BE COOL WITH
50S HIGHS TUESDAY AND WEDNESDAY.
THE DEPARTURE OF WHAT IS LEFT OF THE WEAK WAVE WILL ALLOW THE RIDGE
TO BUILD A LITTLE MORE INTO THE AREA AND BRING DRY WEATHER WITH
MODEST WARMING THURSDAY INTO FRIDAY. LATE FRIDAY AND SATURDAY WILL
BRING A CHANCE OF SHOWERS AND STORMS AS THE PACIFIC TROUGH
APPROACHES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 626 AM CDT SUN MAY 17 2015
SHOWERS WITH EMBEDDED THUNDERSTORMS WILL CONTINUE TO TRACK
NORTHWARD ACROSS THE REGION THIS MORNING...THEN DIMINISH SOUTH TO
NORTH THIS AFTERNOON. MVFR CEILINGS AND VISIBILITY WILL BE
ASSOCIATED WITH RAIN SHOWERS. THE QUESTION IS HOW LONG THE MVFR
CONDITIONS LINGER...AS MODELS VARY WITH CEILING HEIGHTS THIS
AFTERNOON THROUGH TONIGHT. FOR NOW...WILL BRING IN SOME IMPROVE
TO LOW END VFR LATE MORNING AND AFTERNOON AND THEN DROP BACK TO
MVFR THIS EVENING AND TONIGHT AT KFSD AND KHON. KSUX IS LESS
CERTAIN...SO LEFT VFR THERE OVERNIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
645 AM CDT SUN MAY 17 2015
.DISCUSSION...STORMS HAVE BUILT BACK ALL THE WAY TO EAGLE PASS BUT
THE OVERALL PROGRESSION OF THE LINE CONTINUES TO SHOW EAST-SOUTHEAST
MOVEMENT. CURRENT 12Z SOUNDING AT CRP SHOWS A DRY LAYER BETWEEN
850-700 MB LAYER. LATEST HRRR AND RAP ALONG WITH 06Z NAM STILL
SHOW THAT STORMS SHOULD SHOW WEAKENING TREND AS THEY REACH SOUTH
TEXAS AND ENCOUNTER NEGATIVE THETA-E ADVECTION OVER THE COASTAL
PLAINS. SEE AVIATION SECTION FOR 12Z TAFS.
&&
.AVIATION...LOW LEVEL FLOW OF 30-35 KNOTS HAS LIMITED FOG
POTENTIAL OVER INLAND AREAS. MVFR CIGS ARE PREVALENT OVER THE
REGION THIS MORNING. MESOSCALE CONVECTIVE SYSTEM MOVING OUT OF
THE HILL COUNTRY IS EXPECTED TO WEAKEN AS IT MOVES TOWARD
SOUTH TEXAS. BUT STORMS SHOULD PERSIST AND REACH THE NORTHERN
COUNTIES BETWEEN 13-15Z. MENTIONED VCTS AT ALI BUT KEPT THE
MENTION OF CONVECTION OUT OF CRP TAFS. OUTFLOW BOUNDARY AND
DEEPER MOISTURE MAY LEAD TO ANOTHER ROUND OF CONVECTION OVER
THE BRUSH COUNTRY THAT COULD AFFECT LRD LATE THIS AFTERNOON
AND EVENING. MVFR CIGS WILL LIFT BY LATE MORNING WITH VFR
CONDITIONS EXPECTED TO BE PREVALENT BY 18Z. MVFR CIGS WILL
MOVE BACK INTO THE COASTAL PLAINS BY 00Z MONDAY AND BE
PREVALENT OVER ALL OF THE REGION BY 06Z.
&&
.PREV DISCUSSION... /ISSUED 433 AM CDT SUN MAY 17 2015/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER MORNING WITH A
DILEMMA WITH REGARDS TO AN UPSTREAM MESOSCALE CONVECTIVE SYSTEM.
ENVIRONMENT FOR SUSTAINING MCS NOT AS GOOD AS FRIDAY. GOES SOUNDER
IMAGE OF PRECIPITABLE WATER SHOWS DRIER AIR OVER THE NORTHWEST
GULF OF MEXICO ADVECTING NORTHWARD INTO THE REGION. CORFIDI
VECTORS INDICATE THE MCS SHOULD CONTINUE MOVING TO THE SOUTHEAST
TOWARD THE NORTHERN BRUSH COUNTRY AND VICTORIA CROSSROADS REGION
THIS MORNING. 00Z HI-RES ARW/NMM AND 03Z SREF STRONGLY INDICATED
THIS MCS WOULD REACH NORTHERN COUNTIES WHILE THE 00Z NAM/00Z TECH
WRF ALONG WITH 08Z HRRR/RAP SHOWED THE SYSTEM WOULD WEAKEN
SUBSTANTIALLY AS IT NEARED THE AREA THIS MORNING. MCS STILL LOOKS
WELL ORGANIZED AND WILL LEAN TOWARD BETTER RAIN CHANCES MAINLY FOR
THE NORTHERN COUNTIES THIS MORNING. MOST OF THE SHORT RANGE MODELS
KEPT THE HIGHER LOW LEVEL THETA-E RIDGE AXIS OVER THE BRUSH
COUNTRY FOR THIS AFTERNOON. A DECENT UPPER LEVEL JET STREAK WILL
BE MOVING ACROSS NORTHERN MEXICO NOSING INTO THE BRUSH COUNTRY
THIS AFTERNOON. COULD SEE REDEVELOPMENT OF CONVECTION ALONG LEFT
OVER BOUNDARIES THAT WILL LINGER INTO THE EVENING HOURS. HI-RES
MODELS INDICATED THERE COULD BE SOME ISOLATED POCKETS OF HEAVY
RAIN FORM OVER THE BRUSH COUNTRY LATE THIS AFTERNOON INTO THIS
EVENING. IF SCENARIO BECOMES A BIT CLEARER LATER TODAY...A FLASH
FLOOD WATCH MAY BE NEEDED FOR THE WESTERN COUNTIES. THE LOWER
THETA-E AIR MASS OVER THE NORTHWEST GULF OF MEXICO WILL MOVE
INLAND INTO THE COASTAL BEND ON MONDAY WITH THE HIGHER MOISTURE
REMAINING ALONG THE RIO GRANDE. KEPT CHANCE POPS WEST TO GHOST
10 PERCENT POPS ALONG THE COAST MONDAY.
MARINE...SCA WILL CONTINUE FOR THE EARLY MORNING HOURS. EXPECT
AS CONVECTION MOVES CLOSER TO THE REGION...GRADIENT WILL DECREASE
WITH WIND SPEEDS FALLING BELOW SCA CRITERIA. WAVE WATCH MODEL
INDICATED SWELLS WILL BE INCREASING TODAY TO 5 TO 6 FEET AND
CONTINUE INTO MONDAY WITH PERIODS OF 7 TO 8 SECONDS. WITH THE
CONTINUED MODERATE TO STRONG ONSHORE FLOW AND NEAR NEW MOON...WENT
WITH HIGH RISK OF RIP CURRENTS FOR TODAY THROUGH MONDAY.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...MID/UPPER LEVEL RIDGING
IS PROG TO STRENGTHEN ACROSS THE CWA FOR MID WEEK...THOUGH LATEST
RUNS OF THE ECMWF HAVE BACKED OFF A BIT ON NORTHWARD BUILDING OF
RIDGE. DRIER AIR AT H85 IS ALSO PROG TO BUILD IN FROM THE WESTERN
GULF FOR MID WEEK AND THE COMBINATION OF SAID FEATURES SHOULD RESULT
IN VERY LOW PRECIP CHANCES FOR EASTERN AREAS BOTH WED/THU. BEST
CONVECTIVE CHANCES FOR WESTERN AREAS MID WEEK WILL BE ALONG THE RIO
GRANDE WHERE THE DEEPEST MOISTURE WILL BE LOCATED AND WHERE
CONVECTIVE TEMPS HAVE A BETTER CHANCE OF BEING REACHED. RIDGING
BEGINS TO DAMPEN BY LATE IN THE WEEK AS A STRONG MID/UPPER TROUGH
SWINGS INTO THE PLAINS RESULTING IN A RETURN TO A POTENTIAL WET
WEATHER PATTERN FOR SOUTH TEXAS BY LATE IN THE EXTENDED PERIOD AS A
SURFACE FRONT TRIES TO WORK SOUTH INTO CENTRAL TEXAS. TEMPERATURES
THROUGH THE WEEK ARE PROG TO BECOME INCREASINGLY MORE SUMMERLIKE
WITH HIGHS IN THE 90S...LOWS IN THE 70S...ALONG WIT HUMID CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 87 77 87 77 88 / 20 20 10 10 10
VICTORIA 87 76 87 75 89 / 50 20 20 10 10
LAREDO 94 76 94 76 95 / 30 40 20 20 10
ALICE 91 76 90 75 93 / 30 20 20 10 10
ROCKPORT 86 78 86 78 86 / 20 20 10 10 10
COTULLA 89 74 90 75 92 / 50 40 40 20 10
KINGSVILLE 89 77 89 76 90 / 30 20 10 10 10
NAVY CORPUS 86 78 86 77 86 / 20 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK THROUGH MONDAY EVENING FOR THE FOLLOWING
ZONES: ARANSAS...CALHOUN...KLEBERG...NUECES.
GM...SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
TMT/89...AVIATION
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
236 PM PDT SUN MAY 17 2015
.SYNOPSIS...BELOW NORMAL TEMPERATURES WITH MOSTLY DRY CONDITIONS
ARE EXPECTED TO CONTINUE THROUGH FRIDAY. THERE COULD BE A FEW
SHOWERS OVER INTERIOR MOUNTAINS LATE TODAY AND AGAIN THURSDAY AS
WEAK LOW PRESSURE DISTURBANCES MOVE ONSHORE. HIGH PRESSURE AND
WARMER CONDITIONS ARE EXPECTED OVER THE MEMORIAL DAY WEEKEND.
&&
.DISCUSSION...AS OF 02:16 PM PDT SUNDAY...DESPITE MID AND HIGH
CLOUDS...MANAGING TO GET A FEW CONVECTIVE BUILDUPS OVER INTERIOR
MOUNTAINS WHERE SUNSHINE IS MORE PREVALENT. HRRR MODEL CAPTURING
THE CONVECTION OVER NORTHEAST SANTA CLARA COUNTY PRETTY WELL AND
SHOULD PERSIST FOR A FEW MORE HOURS...THEN SHIFT EAST AND DECREASE
THIS EVENING. MODEL ALSO SHOWS ACTIVITY FORMING OVER EASTERN SAN
BENITO COUNTY AND PARTS OF MONTEREY COUNTY...BUT THICKER CLOUDS HAVE
LIMITED CONVECTION. WOULD EXPECT SOME BUILDUPS AND POSSIBLY A
SHOWER IN THIS AREA AS WELL LATER THIS AFTERNOON AS SOME BREAKS IN
MID CLOUDS EXPECTED. OTHER AREA TO WATCH IS EXTREME NORTH BAY OVER
ELEVATED TERRAIN...BUT NOT EXPECTING MORE THAN A FEW CUMULUS
BUILDUPS.
WELL MIXED MARINE LAYER PERSISTS AND IS AT LEAST 3000 FEET DEEP
THIS AFTERNOON NEAR THE COAST AND BAY AREA. TEMPERATURES MOSTLY IN
THE 60S AND NOT MUCH CHANGE EXPECTED IN THE CURRENT COOL
TEMPERATURE REGIME THROUGH AT LEAST THURSDAY. MARINE LAYER SHOULD
REMAIN DEEP THROUGH THE WEEK AS WELL WITH A LINGERING TROF ALONG
THE COAST. SERIES OF SHORT WAVES WILL REINFORCE THIS TROF
THROUGHOUT THE WEEK WITH ONE WAVE MOVING ACROSS THE AREA MONDAY
AND ANOTHER ONE WEDNESDAY AND THURSDAY. STRONGEST FEATURE LOOKS TO
ARRIVE THURSDAY AND PUSHES TOWARD SOUTHERN CALIFORNIA.
MAIN IMPACT ON CENTRAL CALIFORNIA COAST WEATHER WILL BE PERSISTENT
LOW CLOUDS ESPECIALLY NEAR THE COAST...COOL TEMPERATURES...AND MOSTLY
DRY WEATHER. SHOWER THREAT SHOULD BE REDUCED MONDAY AND TUESDAY AS
DYNAMICS AND MOISTURE SHIFT FURTHER INLAND. OUTSIDE CHANCE OF A
SHOWER EACH AFTERNOON IN EXTREME NORTH BAY GIVEN INSTABILITY OVER
TERRAIN. THURSDAY BRINGS A BETTER RISK FOR SHOWERS OVER INTERIOR
AS THE STRONGEST WAVE IN THE SERIES BRINGS CYCLONIC CURVATURE AND
SOME ADDED LIFT TO THE AREA.
RIDGE BUILDS INTO COAST OVER THE WEEKEND...SO DRYING AND WARMING
TREND EXPECTED FROM FRIDAY INTO SUNDAY.
&&
.AVIATION...AS OF 10:45 AM PDT SUNDAY...UPPER LOW JUST OFFSHORE ON
SUNDAY MORNING WILL MOVE SLOWLY INLAND ACROSS THE SF BAY AREA
ON SUNDAY NIGHT AND MONDAY. PERSISTENT ONSHORE FLOW ALONG WITH
SIGNIFICANT LOW LEVEL MOISTURE WILL MAINTAIN MVFR CIGS FOR MUCH OF
THE FORECAST PERIOD. MAY SEE A FEW HOURS OF VFR CONDITIONS THIS
AFTERNOON...BUT MVFR CIGS LIKELY TO REDEVELOP BY EARLY EVENING AND
PERSIST WELL INTO MONDAY. WESTERLY WINDS 10 TO 15
KNOTS...STRONGEST DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS.
VICINITY OF KSFO...MVFR CIGS WILL MOST LIKELY CONTINUE TIL
21-22Z. IFR CONDITIONS WITH MID LEVEL CLOUDS EXPECTED DURING THE
LATE AFTERNOON AND EARLY EVENING HOURS BEFORE LOW CIGS REDEVELOP
BY 03Z...WITH MVFR CONDITIONS LIKELY AGAIN BY 06Z. CONFIDENCE
MODERATE. WESTERLY WINDS 10-17 KTS...STRONGEST FROM LATE AFTERNOON
THROUGH EARLY EVENING.
KSFO BRIDGE APPROACH... SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...SOME BREAKS IN THE LOW CLOUD COVER
THROUGH MID AFTERNOON...OTHERWISE PERSISTENT MVFR CIGS EXPECTED
THROUGH THE FORECAST PERIOD. LIGHT WESTERLY WINDS.
&&
.MARINE...AS OF 8:45 AM PDT SUNDAY...RELATIVELY LIGHT
NORTHWESTERLY WINDS WILL PREVAIL OVER THE COASTAL WATERS THROUGH
MIDWEEK.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: KBB
AVIATION/MARINE: DYKEMA
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
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WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
213 PM PDT SUN MAY 17 2015
.SYNOPSIS...
LOW PRESSURE WILL REMAIN OVER THE REGION UNTIL MONDAY NIGHT AND
BRING A CHANCE OF SPRINKLES AND LIGHT RAIN OVER THE SAN JOAQUIN
VALLEY...AS WELL AS AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE
SIERRA NEVADA AND ADJACENT FOOTHILLS. AFTERWARD...GENERALLY DRY
CONDITIONS AND NEAR AVERAGE TEMPERATURES ARE EXPECTED...EXCEPT FOR
AFTERNOON AND EVENING SHOWERS WITH ISOLATED THUNDERSTORMS OVER THE
HIGHER ELEVATIONS OF THE SIERRA NEVADA...FOR THE REST OF THIS WEEK.
&&
.DISCUSSION...AN UPPER TROUGH...CURRENTLY IMPACTING THE WEST COAST
OF CALIFORNIA...WILL CONTINUE SHIFT EAST OVER CENTRAL
CALIFORNIA...RESULTING IN BELOW NORMAL TEMPERATURES AND UNSETTLED
WEATHER. SCATTERED SHOWERS WERE OBSERVED IN THE SIERRA NEVADA
EARLY THIS AFTERNOON...WITH A FEW LOCATIONS IN TULARE COUNTY
REPORTING RAINFALL RATES AROUND 0.05" PER HOUR. THIS SHOWER
ACTIVITY OVER THE SIERRA CREST IS FORECAST TO INCREASE INTO THE
EARLY EVENING HOURS AS THE HIGH RES ARW...NMM...AND HRRR ARE ALL
IN GOOD AGREEMENT ABOUT THIS INCREASE IN ACTIVITY.
ADDITIONALLY...SCATTERED THUNDERSTORMS ARE ALSO POSSIBLE OVER THE
HIGHER ELEVATIONS AS THE NAM...GFS...AND HIGH RES MODELS SHOW
SURFACE CAPE VALUES EXCEEDING A FEW HUNDRED J/KG. THE NAM SEEMS
TO BE THE OUTLIER WITH REGARDS TO CAPE VALUES...INDICATING OVER
1000 J/KG...WITH A BULLS EYE IN FRESNO COUNTY BETWEEN 2 PM AND 5
PM THIS AFTERNOON. WE WILL CONTINUE TO MONITOR THE CHANCE FOR
THUNDERSTORMS CLOSELY AS THE AFTERNOON PROGRESSES.
LASTLY...SPINKLES WILL BE POSSIBLE IN THE SAN JOAQUIN VALLEY AS
LIGHT RAIN SHOWERS MOVE NORTHEAST INTO THE AREA FROM SOUTHERN
CALIFORNIA.
BY MONDAY AFTERNOON THE UPPER TROUGH WILL SHIFT EAST INTO
NEVADA...HOWEVER SCATTERED SHOWERS WILL REMAIN IN THE AREA. THE
OPERATIONAL HIGH RES MODELS INDICATE SHOWERS OVER THE SIERRA CREST
AGAIN MONDAY AFTERNOON INTO THE EVENING HOURS AND ALSO THE
POSSIBILITY OF ANOTHER DAY OF SPRINKLES IN THE VALLEY. LASTLY...FEW
SHOWERS WILL ALSO BE POSSIBLE NEAR THE GRAPEVINE.
LITTLE CHANGE IN THE UPPER PATTERN THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK AS A SERIES OF UPPER TROUGHS MOVES SOUTHEAST TOWARD THE
CENTRAL CALIFORNIA COAST. THIS PATTERN WILL RESULT IN DAYTIME HIGH
TEMPERATURES REMAINING BELOW NORMAL THROUGH CENTRAL CALIFORNIA AS
WELL AS AFTERNOON AND EVENING SIERRA NEVADA SHOWERS AND
THUNDERSTORMS.
BY THE WEEKEND...UPPER LEVEL HIGH PRESSURE WILL BEGIN TO BUILD
OVER THE REGION RESULTING IN A WARMING TREND ACROSS THE AREA.
&&
.AVIATION...
A FEW SHOWERS OR THUNDERSTORMS POSSIBLE OVER THE SIERRA NEVADA THIS
EVENING...OTHERWISE MAINLY VFR CONDITIONS WILL PREVAIL ACROSS THE
CENTRAL CA INTERIOR THROUGH THE NEXT 24 HOURS.
&&
.AIR QUALITY ISSUES...
NONE.
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS MEDIUM.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.
THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED
BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.
&&
.CLIMATE...
RECORDS
SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR
KFAT 05-17 106:2009 64:2011 73:2008 44:1974
KFAT 05-18 103:2008 63:1994 73:2008 42:1893
KFAT 05-19 103:2008 63:1972 70:2009 42:1896
KBFL 05-17 105:2009 68:1998 73:2009 41:1906
KBFL 05-18 102:2009 68:2011 76:1973 41:1893
KBFL 05-19 101:1954 65:1916 73:1979 38:1893
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...RILEY
AVN/FW...ANDERSEN
SYNOPSIS...BSO
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
331 PM MDT SUN MAY 17 2015
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 331 PM MDT SUN MAY 17 2015
IN SPITE OF BUILDING HIGH PRESSURE OVER UTAH AND WARMING TEMPS
ALOFT...AFTERNOON CAPE VALUES OF 250-500 J/KG SUGGEST CONVECTIVE
SHOWERS WITH SOME THUNDERSTORMS. MOISTURE TRANSPORT DOES EXIST
FROM THE UINTA MOUNTAINS TOWARD VAIL AND INDEPENDENCE PASS
REGION...AND SHOWERS/STORMS WILL BE CONCENTRATED ACROSS THIS AREA.
CONVECTIVE POTENTIAL EXIST ELSEWHERE BUT NOT AS NUMEROUS OVER SW
COLORADO...AND MOSTLY DRY OVER SE UTAH.
CONVECTIVE POTENTIAL MOSTLY DIMINISHES WITH SUNSET. NOT SO SURE
THIS WILL BE THE CASE ACROSS PARTS OF ERN UTAH AS MOISTURE
TRANSPORT INCREASES OVERNIGHT...THE HRRR SHOW CONVECTIVE SHOWERS
PERSISTING PAST MIDNIGHT AND TRACKING OVER THE UINTA
BASIN/MOUNTAINS. BY DAYBREAK...HIGH CLOUDS WILL BE SPREADING FROM
THE SOUTH AS THE NEXT CALIFORNIA UPPER LOW ADVECTS MOISTURE
TOWARDS THE FOUR CORNERS REGION.
THE PACIFIC WAVE TRAIN CONTINUES MONDAY AS THE NEXT STORM SYSTEM
MOVES SLOWLY ONSHORE...ITS CENTER SETTLING OVER CALIFORNIA/S SAN
JOAQUIN VALLEY LATE IN THE AFTERNOON. SOUTHERLY FLOW AHEAD OF THE
TROUGH WILL CAUSE MOISTURE LEVELS TO RISE ONCE AGAIN AS GULF
MOISTURE IS TAPPED. GFS AND NAM BOTH INDICATED PRECIPITABLE WATER
VALUES RISING TO NEAR 0.6 OF AN INCH. MEANWHILE...AN 110 KT JET
ROTATES THROUGH THE BASE OF THE TROUGH GIVING IT A SLIGHTLY
NEGATIVE TILT. THE NOSE OF THE JET PUSHES TOWARD THE FOUR CORNERS
WHICH WILL PROVIDE CONSIDERABLE DIVERGENCE TO ADD TO THE DIFFLUENT
FLOW ALOFT. THE DYNAMIC LIFT JUST DESCRIBED COMBINED WITH DAYTIME
HEATING WILL GENERATE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS FAVORING THE MOUNTAINS. AS MENTIONED IN THE PREVIOUS
DISCUSSION...ARRIVING MOISTURE WILL BE HIGH BASED ACCORDING TO
AREA TIME SECTIONS SO EXPECT MAIN STORM THREAT...ASIDE FROM
LIGHTNING...WILL BE STRONG AND GUSTY OUTFLOW WINDS. WAA ADVECTION
WILL CAUSE TEMPERATURES TO CLIMB CLOSER TO SEASONAL NORMS...
THOUGH EXPECT CLOUDS AND SHOWERS WILL LIMIT HIGHS. THEREFORE...
NUDGED MONDAY/S HIGHS TOWARD COOLER MAV GUIDANCE.
MONDAY NIGHT WILL REMAIN ACTIVE AS THE PACIFIC SYSTEM MOVES OVER
SOUTHERN NEVADA DURING THE NIGHT. DIFFLUENT/DIVERGENT FORCING
REMAINS IN PLACE WHILE MOISTURE CONTINUES TO STREAM INTO THE AREA
FROM THE SOUTH. AS A RESULT...WILL CONTINUE WITH LIKELY POPS IN
THE MOUNTAINS WITH CHANCE POPS ACROSS THE VALLEYS. COLDER AIR
BEGINS TO ADVECT OVER THE REGION DURING THE NIGHT CAUSING SNOW
LEVELS TO LOWER TO AROUND 9000 TO 9500 FEET. EXPECT ACCUMULATING
SNOW FOR AREAS ABOVE 10000 FEET WITH AMOUNTS OF UP TO 8 INCHES
POSSIBLE ABOVE THE TIMBERLINE. MODELS SUGGEST AMOUNTS OF 12 INCHES
OR MORE BUT APPEARS CONVECTIVE PARAMETERIZATION MAY BE A BIT
OVERDONE AS LAPSE RATES ONLY MODERATELY UNSTABLE. IMPACTS TO
ROADWAYS OVER THE HIGH PASSES PROBABLY NEGLIGIBLE WITH MOST SNOW
MELTING ON CONTACT SO WILL HOLD OFF ISSUING HILITES. CLOUDS...
SHOWERS AND WAA WILL YIELD MILDER OVERNIGHT LOWS AS PREVIOUSLY
FORECAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 331 PM MDT SUN MAY 17 2015
COOL AND UNSETTLED CONDITIONS WILL CONTINUE TUESDAY AS THE
PACIFIC STORM MOVES OVER THE REGION. SNOW LEVELS WILL RISE WITH
DAYTIME WARMING...ESPECIALLY SOUTH...WHICH WILL INHIBIT ANY
ADDITIONAL ACCUMULATIONS BELOW 10000 FEET. CONDITIONS IMPROVE
TUESDAY NIGHT AS A TRANSIENT SHORTWAVE RIDGE BUILDS OVER THE AREA.
ANOTHER LOW DEVELOPS OVER THE EASTERN PACIFIC AT MIDWEEK BUT STAYS
QUASI-STATIONARY UNTIL THURSDAY NIGHT. A DRIER SOUTHWEST FLOW
WILL MOVE OVER THE FORECAST AREA AHEAD OF THIS SYSTEM LIMITING
MOIST CONVECTION TO THE MOUNTAIN AREAS DURING THE AFTERNOON AND
EVENING WEDNESDAY AND THURSDAY. TEMPERATURES WILL RECOVER DURING
THIS PERIOD REACHING NEAR NORMAL LEVELS THURSDAY AFTERNOON.
THE PACIFIC SYSTEM THEN FOLLOWS THE WELL BEATEN PATH PREVIOUS
STORMS HAVE TAKEN OVER THE PAST COUPLE OF WEEKS...TRACKING OVER
EASTERN UTAH AND WESTERN COLORADO FRIDAY AND SATURDAY.
CONSEQUENTLY...LOOK FOR AN UPTICK IN SHOWER AND THUNDERSTORM
ACTIVITY ONCE AGAIN ALONG WITH COOLER THAN NORMAL TEMPERATURES.
CONDITIONS ON SUNDAY LESS CERTAIN AS LATEST ECMWF DRIVES A
SHORTWAVE TROUGH ACROSS THE REGION FROM THE NORTHWEST WHILE GFS
FAVORS A TRANSITORY RIDGE. BOTH SOLUTIONS POINT TO A CONTINUATION
OF UNSETTLED CONDITIONS AS MOISTURE WILL LINGER IN EITHER CASE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1135 AM MDT SUN MAY 17 2015
CONVECTIVE SHOWERS WILL INCREASE AFTER 18Z...ESPECIALLY OVER NW
COLORADO WHERE NUMEROUS SHOWERS ARE EXPECTED OVER THE CENTRAL
MOUNTAINS. SKI COUNTRY TAF SITES (KASE...KEGE...KRIL) MOST LIKELY
WILL HAVE SHOWERS MOVE ACROSS THESE SITES WITH CIGS BELOW ILS
BREAKPOINTS. IN BETWEEN PASSING SHOWERS...VFR CONDITIONS MAY
OCCUR.
SHOWERS WILL BE DIMINISHING BETWEEN AFTER 01Z AND ENDING BY 06Z.
VFR PREVAILS OVERNIGHT AND MONDAY MORNING WITH NO AVIATION HAZARDS
EXPECTED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...PF/NL
LONG TERM...NL
AVIATION...PF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
140 PM EDT SUN MAY 17 2015
.SYNOPSIS...
A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH THIS
AFTERNOON...THEN DROPS SOUTHWEST ACROSS THE AREA TONIGHT. THE
FRONT STALLS JUST SOUTHWEST OF THE REGION ON MONDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTHEAST. THIS FRONT WILL LIFT
THROUGH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD
FRONTAL PASSAGE TUESDAY EVENING. HIGH PRESSURE IS THEN IN CONTROL
INTO NEXT WEEKEND...WITH THE EXCEPTION OF A WEAK COLD FRONTAL
PASSAGE ON FRIDAY
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOOKING AT DEVELOPING CUMULUS FIELD ON SATELLITE OVER THE LOWER
HUDSON VALLEY/NE NJ...SO AT THIS POINT HAVE NO REASON TO NOT
BELIEVE HRRR IDEA OF ISOLATED SHOWERS DEVELOPING THERE THIS
AFTERNOON.
WHILE ANY SHRA...WITH VERY LOW CHANCE OF A TSTM...WILL BE OF THE
HIT AND MISS VARIETY...GIVEN LIGHT WINDS ALOFT WILL BE SLOW TO
MOVE...SO COULD PRODUCE LOCALLY HEAVY RAINFALL. ONCE AGAIN...FAR
MORE LIKELY FOR A MISS THAN A HIT ON A SHRA AT ANY GIVEN LOCATION
OVER THE LOWER HUDSON VALLEY/NE NJ/NYC THIS AFTERNOON.
MADE MINOR CHANGES TO TEMPERATURES THIS UPDATE WITH VALUES
EXPECTED TO BE AROUND 10-15 DEGREES ABOVE NORMAL AS A RESULT.
SEABREEZES HAVE DEVELOPED A TAD AHEAD OF SCHEDULE...BUT BASED ON
LATEST TRENDS SHOULD BE SLOW TO MOVE INLAND...ESPECIALLY ACROSS
LONG ISLAND/NYC.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
UPPER LEVEL RIDGE AXIS BUILDS EAST ACROSS NEW ENGLAND
TONIGHT...WHICH IN TURN STRENGTHENS HIGH PRESSURE OVER THE
CANADIAN MARITIMES AND SENDS A BACKDOOR COLD ACROSS THE AREA BY
DAYBREAK. THE FRONT WILL STALL JUST SOUTHWEST OF THE FORECAST
AREA ON MON. HOWEVER..DUE TO THE CLOSE PROXIMITY OF THE BOUNDARY
CAN NOT RULE OUT SHOWERS...PRIMARILY FROM NYC AND POINTS WEST.
CLOUDS MOVE IN BEHIND THE COLD FRONT LATE TONIGHT AS A MOIST E
FLOW DEVELOPS ACROSS THE REGION. SOME CLEARING IS POSSIBLE MON
AFTERNOON ACROSS EASTERN LONG ISLAND/SE CT...WITH A MOSTLY CLOUDY
SKY FURTHER WEST.
LOWS TONIGHT WILL REMAIN MILD WITH THE CLOUD COVER AND DEVELOPING
EAST FLOW...HOWEVER...FOR THOSE SAME REASONS WILL BE ABOUT 5
DEGREES BELOW NORMAL ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE
WEEK WITH ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING
AROUND THE BASE RESULTS IN AMPLIFICATION.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN
THE EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH
PRESSURE THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH
THE END OF THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER
ASSOCIATED WITH A WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI
AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
A COLD FRONT APPROACHES FROM THE NORTH TODAY WITH VFR CONDITIONS
THROUGH THIS EVENING. THE FRONT MOVES THROUGH THE TERMINALS LATE
TONIGHT INTO MONDAY MORNING.
WITH LIGHT FLOW OVER THE AREA...WINDS HAVE BEEN VARIABLE.
SOUTHERLY SEA BREEZES WILL CONTINUE MOVING THROUGH MOST TERMINALS.
OTHERWISE...WINDS SHOULD AVERAGE OUT OF THE SOUTHWEST WHERE SEA
BREEZES DO NOT MOVE THROUGH. SPEEDS WILL BE 5 TO 10 KT...HIGHEST
NEAR THE COAST.
AN ISOLATED SHOWER IS POSSIBLE THIS AFTERNOON AT KEWR/KTEB.
WINDS DIMINISH TO 5 KT OR LESS AFTER 02-03Z TIME FRAME. BEHIND
THE FRONT...WINDS WILL BE OUT OF THE NE-ENE 5 TO 10 KT MONDAY
MORNING.
STRATUS/FOG DEVELOPS AROUND 09Z WITH IFR CONDS AND A LOW CHANCE
OF LIFR IN VISIBILITIES. SLIGHT IMPROVEMENT TO MVFR EXPECTED
AROUND 15Z...BUT IFR CONDS COULD LAST LONGER THAN CURRENTLY
FORECAST.
.OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
.MONDAY AFTERNOON-MONDAY EVENING...MVFR CIGS LIKELY IN STRATUS.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE ON
WEDNESDAY.
&&
.MARINE...
MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK.
A BACKDOOR COLD FRONT APPROACHES THE WATERS FROM THE NORTH THIS
AFTERNOON AND PASSES TO SOUTH OF THE WATERS BY EARLY MONDAY
MORNING. THE PRESSURE GRADIENT GRADUALLY TIGHTENS AS HIGH PRES
BUILDS ALONG THE NEW ENGLAND COAST AND A COLD FRONT APPROACHES
FROM THE WEST. THAT FRONT MOVES ACROSS THE WATERS LATE
TUESDAY...AND THEN HIGH PRES RETURNS FOR THE MIDDLE OF THE WEEK.
SUB-SMALL CRAFT ADVISORY CONDITIONS ON TAP THROUGH MONDAY...AND
THEN SCA CONDITIONS EXPECTED ON WEDNESDAY BEHIND THE DEPARTING
COLD FRONT.
&&
.HYDROLOGY...
GENERALLY LIGHT RAINFALL AMOUNTS ARE POSSIBLE IN ANY SHOWERS THE
NEXT COUPLE OF DAYS...MAINLY WEST OF NYC.
HOWEVER...ANY SHOWERS WHICH DO FORM THIS AFTERNOON WILL BE VERY
SLOW TO MOVE. IF ANY STRONGER CONVECTION WERE TO FORM OVER A
LOCATION...THERE WOULD BE THE POTENTIAL FOR THE PONDING OF WATER
ON ROADWAYS AND POSSIBLY MINOR POOR DRAINAGE FLOODING DEPENDING ON
THE EXACT DURATION AND STRENGTH OF ANY GIVEN SHOWER WHICH MIGHT
FORM.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/DW
NEAR TERM...MALOIT/DW
SHORT TERM...DW
LONG TERM...24/DW
AVIATION...DS
MARINE...MALOIT/MPS
HYDROLOGY...MALOIT/DW
AREA FORECAST DISCUSSION
NWS ALBANY NY
109 PM EDT SUN MAY 17 2015
.SYNOPSIS...
A COLD FRONT WILL DRIFT SOUTH OF THE REGION TODAY...AS
HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN CANADA. THE FRONTAL
BOUNDARY WILL BE STATIONARY SOUTH OF EAST CENTRAL NEW YORK TONIGHT
INTO MONDAY BEFORE A LOW PRESSURE SYSTEM AND COLD FRONT APPROACHES
FROM THE GREAT LAKES REGION AND THE MIDWEST WITH INCREASING CHANCES
OF SHOWERS AND THUNDERSTORMS LATE MONDAY INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM EDT...MESOSCALE ANALYSIS REVEALS THE COLD FRONT HAS
STALLED ALONG OUR SOUTHERN PERIPHERY OF OUR CWFA. LAPS/SPC
ANALYSIS WINDOWS SUGGEST SBCAPES HAVE RISEN TO NEAR 1K J/KG.
HOWEVER...THE 12Z SOUNDINGS FROM KALB-KOKX...SHOW THE INVERSION
LAYER WAS BELOW -20C SO THE POTENTIAL FOR THUNDER LOOKS RATHER
LOW. HOWEVER...DPROG/DT OF THE HRRR REFLECTIVITY FORECASTS HAVE
SHOWN AN INCREASE OF ISOLATED SHOWERS SO WITH THIS UPDATE WE WILL
PLACE A SLIGHT CHANCE POPS FOR ULSTER/DUTCHESS/LITCHFIELD COUNTIES
WITH MAINLY THE SOUTHERN PORTIONS OF THESE COUNTIES. THE H2O VAPOR
LOOP DOES SHOW HINTS OF A WEAK SHORT WAVE OVER WESTERN NY WITH
RAP13/HRRR FORECASTS MOVING THIS FEATURE ACROSS THE SOUTHERN
PORTIONS OF THE REGION TO FURTHER SUPPORT THE SLIGHT CHANCE
UPGRADE FOR SHOWERS. OTHERWISE...A DELIGHTFUL END TO THE WEEKEND
WITH TEMPERATURES CLIMBING INTO THE LOWER HALF OF THE 80S WITH 70S
ACROSS THE HIGHER TERRAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...THE SFC CYCLONE DRIFTS N/NE OF UPSTATE NY OVER NRN
MAINE AND THE CANADIAN MARITIMES. THE MID-LEVEL RIDGE AXIS SETS UP
OVER ERN NY AND WRN NEW ENGLAND. A CLEAR/MOSTLY CLEAR AND COOL
NIGHT IS EXPECTED WITH SOME RADIATIONAL COOLING EXPECTED EARLY
ON. SOME STRATUS MAY START TO MOVE IN SOUTH OF MASS PIKE AND OVER
THE MID HUDSON VALLEY BTWN 09Z-12Z MONDAY MORNING. LOWS WILL
GENERALLY BE IN THE MID TO U50S FROM THE CAPITAL REGION...MOHAWK
VALLEY...AND BERKSHIRES SOUTH...AND M40S TO L50S TO THE NORTH.
MONDAY...A BACKDOOR COLD FRONT DRIFTS WESTWARD ACROSS THE
REGION...AND STALLS OVER CNTRL NY WITH THE SFC HIGH BUILDING IN
FROM THE GULF OF MAINE AND NEW BRUNSWICK. LOW PRESSURE UPSTREAM
OVER THE UPPER MIDWEST/WRN GREAT LAKES REGION WILL EDGE CLOSER
ASSOCIATED WITH A POSITIVELY TILTED UPPER TROUGH. A FEW ISOLATED
SHOWERS WILL BE POSSIBLE OVER WRN NEW ENGLAND AND THE HIGHER
TERRAIN OF EASTERN NY WITH THE BACKDOOR FRONT. IT WILL BE CLOUDY
AND COOLER THAN SUNDAY. A MID-LEVEL SHORT-WAVE IN THE SW
FLOW...AND THE BACKDOOR FRONT WILL TRY TO MOVE BACK EASTWARD AS A
WARM FRONT DURING THE MID TO LATE AFTERNOON TO INCREASE THE THREAT
OF SHOWERS AND PERHAPS SOME ISOLATED THUNDERSTORMS WEST OF THE
HUDSON VALLEY. HIGHS WILL ONLY BE IN THE MID 60S TO NEAR 70F OVER
WRN NEW ENGLAND. EXPECT U60S TO M70S OVER ERN NY.
MONDAY NIGHT...THE WARM FRONT OR PREFRONTAL THERMAL TROUGH TO THE
SYSTEM WILL SLOWLY MOVE ACROSS THE REGION. MOISTURE POOLS AHEAD OF
THE TROUGH WITH SFC DEWPTS RISING INTO THE 50S. THE LATEST
SHOWALTER VALUES LOWER TO 0 TO -1C WITH SOME MUCAPE. THE
INCREASING MOISTURE CONVERGENCE WITH RISING PWAT VALUE A FEW
STANDARD DEVIATIONS ABOVE NORMAL SHOULD ALLOW FOR A BAND OR BANDS
OF SHOWERS WITH EMBEDDED THUNDERSTORMS. INITIALLY THESE SHOWERS
AND STORMS WILL BE NORTH AND WEST OF THE CAPITAL DISTRICT PRIOR TO
06Z/TUE...AND THEN FROM THE CAPITAL DISTRICT SOUTH AND EAST BTWN
06Z- 12Z. POPS WERE KEPT IN THE LIKELY RANGE...EXCEPT HIGH CHC
FOR THE MID HUDSON VALLEY...SRN BERKS...AND NW CT. LOWS WILL BE OF
THE WET BULB VARIETY WITH M50S TO AROUND 60F.
TUESDAY...A HUMID AIR MASS WILL BE OVER THE REGION WITH LIMITED
INSOLATION DUE TO THE CLOUD COVER EARLY. IF THE CLOUDS
THIN...THEN MODEST AMOUNTS OF SFC BASED INSTABILITY IN THE
500-1000 J/KG RANGE MAY MATERIALIZE BASED ON THE GFS. LIFTED
INDICES IN THE -3C TO -5C RANGE WITH STRENGTHENING 0-6 KM BULK
SHEAR TO 30 TO 40 KTS BY 18Z/TUE...AND 40-50 KTS BY 00Z/WED. THE
MID LEVEL LAPSE RATES LOOK WEAK UNTIL THE NIGHT TIME PERIOD. SOME
DEEP ORGANIZED CONVECTION IS POSSIBLE...BUT WHETHER IT IS STRONG
TO SEVERE IS STILL A BIT UNCLEAR DUE TO POTENTIAL CLOUD
COVER...AND HOW MUCH INSTABILITY IS AVAILABLE. THE LATEST SPC DAY
3 CAME OUT WITH A MARGINAL THREAT FOR MOST OF THE REGION. THAT
SEEMS REASONABLE WITH THE APPROACHING FRONT AND PERHAPS AN
ISOLATED THREAT FOR A FEW SEVERE IF ANY ORGANIZED LINE GETS GOING.
PWATS WILL STILL BE IN THE INCH TO INCH A THIRD RANGE...AND SOME
LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. HIGHS WILL BE IN THE
70-75F RANGE IN THE VALLEY AREAS...AND M60S TO NEAR 70F OVER THE
MTNS.
TUESDAY NIGHT...THE SFC COLD FRONT MOVES THROUGH...AND THE UPPER
LEVEL TROUGH AXIS WILL BE FOLLOWING IT. THE BEST CHC OF SHOWERS
WILL BE OVER THE MTNS NORTH AND WEST OF THE CAPITAL REGION. A
COOLER AND DRIER AIR MASS WILL BE FILTERING IN FOR THE MID WEEK.
LOWS WILL BE IN THE MID AND U40S NORTH AND WEST OF THE CAPITAL
DISTRICT...AND LOWER TO M50S FROM THE CAPITAL DISTRICT SOUTH AND
EAST. TOTAL RAINFALL COULD BE IN THE QUARTER OF AN INCH TO INCH
RANGE BY WEDNESDAY MORNING...WITH SOME LOCATIONS GETTING A FEW
INCHES WHERE THE CONVECTION OCCURS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY WILL BE A BRISK AND COOLER DAY IN WAKE OF THE LOW
PRESSURE SYSTEM WHICH WILL MOVE OFF TO OUR EAST TUESDAY NIGHT.
GUSTY WEST TO NORTHWEST WINDS WILL USHER IN A COOLER AIR MASS WITH
TEMPERATURES EXPECTED TO RUN AROUND 10 DEGREES BELOW
NORMAL....WITH A LARGE RANGE ACROSS THE FORECAST AREA FROM THE
LOWER 50S TO UPPER 60S. WITH CYCLONIC FLOW ACROSS THE REGION AND
COLD AIR ALOFT A PARTLY SUNNY TO MOSTLY CLOUDY DAY IS ANTICIPATED
WITH GREATER CLOUD COVER ACROSS THE HIGHER TERRAIN.
IT WILL FEEL CHILLY WEDNESDAY NIGHT WITH LOWS EXPECTED TO FALL INTO THE
MID 30S TO MID 40S...WHICH ARE NEAR SEASONABLE.
THE REGION WILL REMAIN ON THE SOUTHERN PERIPHERY OF THE LONGWAVE TROUGH
OVER EASTERN CANADA. THE FLOW ALOFT FOR THURSDAY IS EXPECTED TO BECOME
FAIRLY ZONAL WITH SOME HIGHER PRESSURE BUILDING IN AT THE SURFACE...SO
EXPECTING DRY WEATHER...LIGHTER WESTERLY WINDS AND NEAR SEASONABLE
TEMPERATURES.
A SHORT WAVE ROTATING ABOUT THE UPPER LOW THROUGH THE BASE OF THE
TROUGH FRIDAY SHOULD BRING A WEAK FRONTAL BOUNDARY AT LEAST THE NORTHERN
REACHES OF THE REGION. AT THIS TIME...MOISTURE ASSOCIATED WITH THE
BOUNDARY SHOULD BE LIMITED SO HAVE A FAIR WEATHER FORECAST.
AS WE HEAD INTO MEMORIAL DAY WEEKEND HIGH PRESSURE AT THE SURFACE AND
ALOFT ARE MODELED TO BUILD INTO THE REGION AND RESULT IN FAIR WEATHER
FOR SATURDAY AND HOPEFULLY ALL OF SUNDAY TOO. A LOW PRESSURE SYSTEM IS
MODELED TO BE MOVING INTO THE GREAT LAKES REGION. THE GFS IS STRONGER
WITH THIS SYSTEM THAN THE ECMWF WHICH COULD BEGIN TO AFFECT THE REGION
SUNDAY.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
A WEAK COLD FRONTAL BOUNDARY HAS MOVED SOUTH OF THE FA OVER
SOUTHEAST NY. IN ITS WAKE A LARGE RIDGE OF HIGH PRESSURE WAS
BUILDING SOUTHEAST FROM SOUTHERN ONTARIO. AS A RESULT SKIES FOR
THE REMAINDER OF THIS AFTERNOON INTO THE OVERNIGHT WILL BE MAINLY
SKC-SCT045 SCT250 WITH MORE IN THE WAY OF CLOUDS AT KPOU WHICH
WILL BE CLOSER TO THE FRONTAL BOUNDARY WITH BKN040 BKN060
EXPECTED.
MAINLY MOSTLY CLEAR SKIES ARE EXPECTED TONIGHT HOWEVER SOME
STRATUS MAY MOVE IN TOWARD SUNRISE WITH THE LIGHT ONSHORE FLOW OFF
THE ATLANTIC ESPECIALLY AT KPSF AND KPOU...OTHERWISE KALB AND KGFL
WILL BE MAINLY SCT250 MONDAY MORNING.
WINDS WILL BE GENERALLY VARIABLE AT 10 KTS OR LESS THIS
AFTERNOON...BECOMING LIGHT AND VARIABLE TONIGHT AND THEN S-SE AT
5-10 KTS ON MONDAY MORNING.
OUTLOOK...
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
WEDNESDAY: LOW OPERATIONAL IMPACT. BREEZY NO SIG WX.
WEDNESDAY NIGHT TO THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX
&&
.FIRE WEATHER...
A COLD FRONT WILL DRIFT SOUTH OF THE REGION TODAY...AS
HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN CANADA. THE FRONTAL
BOUNDARY WILL BE STATIONARY SOUTH OF EAST CENTRAL NEW YORK TONIGHT
INTO MONDAY BEFORE A LOW PRESSURE SYSTEM AND COLD FRONT APPROACHES
FROM THE GREAT LAKES REGION AND THE MIDWEST WITH INCREASING CHANCES
OF SHOWERS AND THUNDERSTORMS LATE MONDAY INTO TUESDAY.
THE RH VALUES WILL LOWER TO 25 TO 40 PERCENT THIS AFTERNOON...AND
THEN HAVE AN EXCELLENT RECOVERY TO 85 TO 100 PERCENT TONIGHT WITH
SOME DEW FORMATION. EXPECT THE RH VALUES TO LOWER TO 45 TO 60
PERCENT MONDAY AFTERNOON.
THE WINDS WILL BE FROM THE NORTH TO NORTHWEST AT 5 TO 15 MPH THIS
AFTERNOON...AND THEN LIGHT TO CALM TONIGHT. THE WINDS WILL BE FROM
THE SOUTHEAST TO SOUTH AT 5 TO 15 MPH ON MONDAY.
THE NEXT CHANCE OF A WIDESPREAD RAINFALL IN TERMS OF SHOWERS AND
THUNDERSTORMS WILL BE LATE MONDAY INTO TUESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS.
DRY WEATHER WILL PERSIST TODAY INTO EARLY MONDAY. CHANCES OF
SHOWERS AND THUNDERSTORMS INCREASE LATE MONDAY AFTERNOON THROUGH
TUESDAY. MOST OF THE HYDRO SERVICE AREA COULD GET A QUARTER OF AN
INCH TO AN INCH OF RAINFALL...BUT LOCALLY HIGHER AMOUNTS ARE
POSSIBLE IN THUNDERSTORMS. DRY CONDITIONS WILL RETURN WED TO END
THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...BGM/11/WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA/11
FIRE WEATHER...WASULA
HYDROLOGY...SNYDER/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1254 PM EDT SUN MAY 17 2015
.SYNOPSIS...
A COLD FRONT WILL DRIFT SOUTH OF THE REGION TODAY...AS
HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN CANADA. THE FRONTAL
BOUNDARY WILL BE STATIONARY SOUTH OF EAST CENTRAL NEW YORK TONIGHT
INTO MONDAY BEFORE A LOW PRESSURE SYSTEM AND COLD FRONT APPROACHES
FROM THE GREAT LAKES REGION AND THE MIDWEST WITH INCREASING CHANCES
OF SHOWERS AND THUNDERSTORMS LATE MONDAY INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM EDT...MESOSCALE ANALYSIS REVEALS THE COLD FRONT HAS
STALLED ALONG OUR SOUTHERN PERIPHERY OF OUR CWFA. LAPS/SPC
ANALYSIS WINDOWS SUGGEST SBCAPES HAVE RISEN TO NEAR 1K J/KG.
HOWEVER...THE 12Z SOUNDINGS FROM KALB-KOKX...SHOW THE INVERSION
LAYER WAS BELOW -20C SO THE POTENTIAL FOR THUNDER LOOKS RATHER
LOW. HOWEVER...DPROG/DT OF THE HRRR REFLECTIVITY FORECASTS HAVE
SHOWN AN INCREASE OF ISOLATED SHOWERS SO WITH THIS UPDATE WE WILL
PLACE A SLIGHT CHANCE POPS FOR ULSTER/DUTCHESS/LITCHFIELD COUNTIES
WITH MAINLY THE SOUTHERN PORTIONS OF THESE COUNTIES. THE H2O VAPOR
LOOP DOES SHOW HINTS OF A WEAK SHORT WAVE OVER WESTERN NY WITH
RAP13/HRRR FORECASTS MOVING THIS FEATURE ACROSS THE SOUTHERN
PORTIONS OF THE REGION TO FURTHER SUPPORT THE SLIGHT CHANCE
UPGRADE FOR SHOWERS. OTHERWISE...A DELIGHTFUL END TO THE WEEKEND
WITH TEMPERATURES CLIMBING INTO THE LOWER HALF OF THE 80S WITH 70S
ACROSS THE HIGHER TERRAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...THE SFC CYCLONE DRIFTS N/NE OF UPSTATE NY OVER NRN
MAINE AND THE CANADIAN MARITIMES. THE MID-LEVEL RIDGE AXIS SETS UP
OVER ERN NY AND WRN NEW ENGLAND. A CLEAR/MOSTLY CLEAR AND COOL
NIGHT IS EXPECTED WITH SOME RADIATIONAL COOLING EXPECTED EARLY
ON. SOME STRATUS MAY START TO MOVE IN SOUTH OF MASS PIKE AND OVER
THE MID HUDSON VALLEY BTWN 09Z-12Z MONDAY MORNING. LOWS WILL
GENERALLY BE IN THE MID TO U50S FROM THE CAPITAL REGION...MOHAWK
VALLEY...AND BERKSHIRES SOUTH...AND M40S TO L50S TO THE NORTH.
MONDAY...A BACKDOOR COLD FRONT DRIFTS WESTWARD ACROSS THE
REGION...AND STALLS OVER CNTRL NY WITH THE SFC HIGH BUILDING IN
FROM THE GULF OF MAINE AND NEW BRUNSWICK. LOW PRESSURE UPSTREAM
OVER THE UPPER MIDWEST/WRN GREAT LAKES REGION WILL EDGE CLOSER
ASSOCIATED WITH A POSITIVELY TILTED UPPER TROUGH. A FEW ISOLATED
SHOWERS WILL BE POSSIBLE OVER WRN NEW ENGLAND AND THE HIGHER
TERRAIN OF EASTERN NY WITH THE BACKDOOR FRONT. IT WILL BE CLOUDY
AND COOLER THAN SUNDAY. A MID-LEVEL SHORT-WAVE IN THE SW
FLOW...AND THE BACKDOOR FRONT WILL TRY TO MOVE BACK EASTWARD AS A
WARM FRONT DURING THE MID TO LATE AFTERNOON TO INCREASE THE THREAT
OF SHOWERS AND PERHAPS SOME ISOLATED THUNDERSTORMS WEST OF THE
HUDSON VALLEY. HIGHS WILL ONLY BE IN THE MID 60S TO NEAR 70F OVER
WRN NEW ENGLAND. EXPECT U60S TO M70S OVER ERN NY.
MONDAY NIGHT...THE WARM FRONT OR PREFRONTAL THERMAL TROUGH TO THE
SYSTEM WILL SLOWLY MOVE ACROSS THE REGION. MOISTURE POOLS AHEAD OF
THE TROUGH WITH SFC DEWPTS RISING INTO THE 50S. THE LATEST
SHOWALTER VALUES LOWER TO 0 TO -1C WITH SOME MUCAPE. THE
INCREASING MOISTURE CONVERGENCE WITH RISING PWAT VALUE A FEW
STANDARD DEVIATIONS ABOVE NORMAL SHOULD ALLOW FOR A BAND OR BANDS
OF SHOWERS WITH EMBEDDED THUNDERSTORMS. INITIALLY THESE SHOWERS
AND STORMS WILL BE NORTH AND WEST OF THE CAPITAL DISTRICT PRIOR TO
06Z/TUE...AND THEN FROM THE CAPITAL DISTRICT SOUTH AND EAST BTWN
06Z- 12Z. POPS WERE KEPT IN THE LIKELY RANGE...EXCEPT HIGH CHC
FOR THE MID HUDSON VALLEY...SRN BERKS...AND NW CT. LOWS WILL BE OF
THE WET BULB VARIETY WITH M50S TO AROUND 60F.
TUESDAY...A HUMID AIR MASS WILL BE OVER THE REGION WITH LIMITED
INSOLATION DUE TO THE CLOUD COVER EARLY. IF THE CLOUDS
THIN...THEN MODEST AMOUNTS OF SFC BASED INSTABILITY IN THE
500-1000 J/KG RANGE MAY MATERIALIZE BASED ON THE GFS. LIFTED
INDICES IN THE -3C TO -5C RANGE WITH STRENGTHENING 0-6 KM BULK
SHEAR TO 30 TO 40 KTS BY 18Z/TUE...AND 40-50 KTS BY 00Z/WED. THE
MID LEVEL LAPSE RATES LOOK WEAK UNTIL THE NIGHT TIME PERIOD. SOME
DEEP ORGANIZED CONVECTION IS POSSIBLE...BUT WHETHER IT IS STRONG
TO SEVERE IS STILL A BIT UNCLEAR DUE TO POTENTIAL CLOUD
COVER...AND HOW MUCH INSTABILITY IS AVAILABLE. THE LATEST SPC DAY
3 CAME OUT WITH A MARGINAL THREAT FOR MOST OF THE REGION. THAT
SEEMS REASONABLE WITH THE APPROACHING FRONT AND PERHAPS AN
ISOLATED THREAT FOR A FEW SEVERE IF ANY ORGANIZED LINE GETS GOING.
PWATS WILL STILL BE IN THE INCH TO INCH A THIRD RANGE...AND SOME
LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. HIGHS WILL BE IN THE
70-75F RANGE IN THE VALLEY AREAS...AND M60S TO NEAR 70F OVER THE
MTNS.
TUESDAY NIGHT...THE SFC COLD FRONT MOVES THROUGH...AND THE UPPER
LEVEL TROUGH AXIS WILL BE FOLLOWING IT. THE BEST CHC OF SHOWERS
WILL BE OVER THE MTNS NORTH AND WEST OF THE CAPITAL REGION. A
COOLER AND DRIER AIR MASS WILL BE FILTERING IN FOR THE MID WEEK.
LOWS WILL BE IN THE MID AND U40S NORTH AND WEST OF THE CAPITAL
DISTRICT...AND LOWER TO M50S FROM THE CAPITAL DISTRICT SOUTH AND
EAST. TOTAL RAINFALL COULD BE IN THE QUARTER OF AN INCH TO INCH
RANGE BY WEDNESDAY MORNING...WITH SOME LOCATIONS GETTING A FEW
INCHES WHERE THE CONVECTION OCCURS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY WILL BE A BRISK AND COOLER DAY IN WAKE OF THE LOW
PRESSURE SYSTEM WHICH WILL MOVE OFF TO OUR EAST TUESDAY NIGHT.
GUSTY WEST TO NORTHWEST WINDS WILL USHER IN A COOLER AIR MASS WITH
TEMPERATURES EXPECTED TO RUN AROUND 10 DEGREES BELOW
NORMAL....WITH A LARGE RANGE ACROSS THE FORECAST AREA FROM THE
LOWER 50S TO UPPER 60S. WITH CYCLONIC FLOW ACROSS THE REGION AND
COLD AIR ALOFT A PARTLY SUNNY TO MOSTLY CLOUDY DAY IS ANTICIPATED
WITH GREATER CLOUD COVER ACROSS THE HIGHER TERRAIN.
IT WILL FEEL CHILLY WEDNESDAY NIGHT WITH LOWS EXPECTED TO FALL INTO THE
MID 30S TO MID 40S...WHICH ARE NEAR SEASONABLE.
THE REGION WILL REMAIN ON THE SOUTHERN PERIPHERY OF THE LONGWAVE TROUGH
OVER EASTERN CANADA. THE FLOW ALOFT FOR THURSDAY IS EXPECTED TO BECOME
FAIRLY ZONAL WITH SOME HIGHER PRESSURE BUILDING IN AT THE SURFACE...SO
EXPECTING DRY WEATHER...LIGHTER WESTERLY WINDS AND NEAR SEASONABLE
TEMPERATURES.
A SHORT WAVE ROTATING ABOUT THE UPPER LOW THROUGH THE BASE OF THE
TROUGH FRIDAY SHOULD BRING A WEAK FRONTAL BOUNDARY AT LEAST THE NORTHERN
REACHES OF THE REGION. AT THIS TIME...MOISTURE ASSOCIATED WITH THE
BOUNDARY SHOULD BE LIMITED SO HAVE A FAIR WEATHER FORECAST.
AS WE HEAD INTO MEMORIAL DAY WEEKEND HIGH PRESSURE AT THE SURFACE AND
ALOFT ARE MODELED TO BUILD INTO THE REGION AND RESULT IN FAIR WEATHER
FOR SATURDAY AND HOPEFULLY ALL OF SUNDAY TOO. A LOW PRESSURE SYSTEM IS
MODELED TO BE MOVING INTO THE GREAT LAKES REGION. THE GFS IS STRONGER
WITH THIS SYSTEM THAN THE ECMWF WHICH COULD BEGIN TO AFFECT THE REGION
SUNDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A WEAK COLD FRONTAL BOUNDARY HAS MOVED ACROSS THE LOCAL AREA.
THE FLOW ALOFT WILL CAUSE THIS BOUNDARY STALL IN THE VICINITY
OF THE NY/PA BORDER TODAY. THE SHORT WAVE TROUGH WILL CONTINUE TO
MOVE SOUTHEASTWARD DOWN THE EAST SIDE OF THE RIDGE AXIS TODAY
AWAY FORM THE LOCAL AREA AND THE UPPER RIDGE WILL STRENGTHEN.
THE RIDGE AXIS INITIALLY TO OUR WEST WILL SHIFT EAST AND ACROSS
THE REGION TONIGHT.
HAVE HAD VARIABLE CLOUDY SKIES ACROSS AREA AND WITH CALM WINDS
AND WET GROUND WHERE SKIES HAVE CLEARED OUT FOR ANY PERIOD OF TIME
IFR-MVFR FOG DEVELOPED. THE ATMOSPHERE WILL MIX AND THE FOG WILL
BURN OFF. CLOUD COVER WILL DECREASE TODAY. MAINLY MOSTLY CLEAR SKIES
ARE EXPECTED TONIGHT HOWEVER SOME STRATUS MAY MOVE IN TOWARD SUNRISE
WITH THE LIGHT ONSHORE FLOW OFF THE ATLANTIC.
LIGHT AND VARIABLE TO CALM WINDS OVERNIGHT BECOMING WEST TO NORTHWEST
AT LESS THAN 10 KNOTS. THE EXCEPTION WILL BE AT KGFL WHERE THE
FLOW IS EXPECTED TO BE NORTHEASTERLY.
OUTLOOK...
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
WEDNESDAY: LOW OPERATIONAL IMPACT. BREEZY NO SIG WX.
WEDNESDAY NIGHT TO THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX
&&
.FIRE WEATHER...
A COLD FRONT WILL DRIFT SOUTH OF THE REGION TODAY...AS
HIGH PRESSURE WILL BUILD IN FROM SOUTHEASTERN CANADA. THE FRONTAL
BOUNDARY WILL BE STATIONARY SOUTH OF EAST CENTRAL NEW YORK TONIGHT
INTO MONDAY BEFORE A LOW PRESSURE SYSTEM AND COLD FRONT APPROACHES
FROM THE GREAT LAKES REGION AND THE MIDWEST WITH INCREASING CHANCES
OF SHOWERS AND THUNDERSTORMS LATE MONDAY INTO TUESDAY.
THE RH VALUES WILL LOWER TO 25 TO 40 PERCENT THIS AFTERNOON...AND
THEN HAVE AN EXCELLENT RECOVERY TO 85 TO 100 PERCENT TONIGHT WITH
SOME DEW FORMATION. EXPECT THE RH VALUES TO LOWER TO 45 TO 60
PERCENT MONDAY AFTERNOON.
THE WINDS WILL BE FROM THE NORTH TO NORTHWEST AT 5 TO 15 MPH THIS
AFTERNOON...AND THEN LIGHT TO CALM TONIGHT. THE WINDS WILL BE FROM
THE SOUTHEAST TO SOUTH AT 5 TO 15 MPH ON MONDAY.
THE NEXT CHANCE OF A WIDESPREAD RAINFALL IN TERMS OF SHOWERS AND
THUNDERSTORMS WILL BE LATE MONDAY INTO TUESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS.
DRY WEATHER WILL PERSIST TODAY INTO EARLY MONDAY. CHANCES OF
SHOWERS AND THUNDERSTORMS INCREASE LATE MONDAY AFTERNOON THROUGH
TUESDAY. MOST OF THE HYDRO SERVICE AREA COULD GET A QUARTER OF AN
INCH TO AN INCH OF RAINFALL...BUT LOCALLY HIGHER AMOUNTS ARE
POSSIBLE IN THUNDERSTORMS. DRY CONDITIONS WILL RETURN WED TO END
THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...BGM/11/WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...WASULA
HYDROLOGY...SNYDER/WASULA
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1241 PM EDT SUN MAY 17 2015
.SYNOPSIS...
A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH THIS
AFTERNOON...THEN DROPS SOUTHWEST ACROSS THE AREA TONIGHT. THE
FRONT STALLS JUST SOUTHWEST OF THE REGION ON MONDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTHEAST. THIS FRONT WILL LIFT
THROUGH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD
FRONTAL PASSAGE TUESDAY EVENING. HIGH PRESSURE IS THEN IN CONTROL
INTO NEXT WEEKEND...WITH THE EXCEPTION OF A WEAK COLD FRONTAL
PASSAGE ON FRIDAY
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOOKING AT DEVELOPING CUMULUS FIELD ON SATELLITE OVER THE LOWER
HUDSON VALLEY/NE NJ...SO AT THIS POINT HAVE NO REASON TO NOT
BELIEVE HRRR IDEA OF ISOLATED SHOWERS DEVELOPING THERE THIS
AFTERNOON.
WHILE ANY SHRA...WITH VERY LOW CHANCE OF A TSTM...WILL BE OF THE
HIT AND MISS VARIETY...GIVEN LIGHT WINDS ALOFT WILL BE SLOW TO
MOVE...SO COULD PRODUCE LOCALLY HEAVY RAINFALL. ONCE AGAIN...FAR
MORE LIKELY FOR A MISS THAN A HIT ON A SHRA AT ANY GIVEN LOCATION
OVER THE LOWER HUDSON VALLEY/NE NJ/NYC THIS AFTERNOON.
MADE MINOR CHANGES TO TEMPERATURES THIS UPDATE WITH VALUES
EXPECTED TO BE AROUND 10-15 DEGREES ABOVE NORMAL AS A RESULT.
SEABREEZES HAVE DEVELOPED A TAD AHEAD OF SCHEDULE...BUT BASED ON
LATEST TRENDS SHOULD BE SLOW TO MOVE INLAND...ESPECIALLY ACROSS
LONG ISLAND/NYC.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
UPPER LEVEL RIDGE AXIS BUILDS EAST ACROSS NEW ENGLAND
TONIGHT...WHICH IN TURN STRENGTHENS HIGH PRESSURE OVER THE
CANADIAN MARITIMES AND SENDS A BACKDOOR COLD ACROSS THE AREA BY
DAYBREAK. THE FRONT WILL STALL JUST SOUTHWEST OF THE FORECAST
AREA ON MON. HOWEVER..DUE TO THE CLOSE PROXIMITY OF THE BOUNDARY
CAN NOT RULE OUT SHOWERS...PRIMARILY FROM NYC AND POINTS WEST.
CLOUDS MOVE IN BEHIND THE COLD FRONT LATE TONIGHT AS A MOIST E
FLOW DEVELOPS ACROSS THE REGION. SOME CLEARING IS POSSIBLE MON
AFTERNOON ACROSS EASTERN LONG ISLAND/SE CT...WITH A MOSTLY CLOUDY
SKY FURTHER WEST.
LOWS TONIGHT WILL REMAIN MILD WITH THE CLOUD COVER AND DEVELOPING
EAST FLOW...HOWEVER...FOR THOSE SAME REASONS WILL BE ABOUT 5
DEGREES BELOW NORMAL ON MON.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE
WEEK WITH ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING
AROUND THE BASE RESULTS IN AMPLIFICATION.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN
THE EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH
PRESSURE THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH
THE END OF THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER
ASSOCIATED WITH A WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI
AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A COLD FRONT APPROACHES FROM THE NORTH TODAY...AND MOVES THROUGH
THE REGION LATE TONIGHT INTO MONDAY MORNING.
CONDITIONS CONTINUE TO SLOWLY IMPROVE WITH SOME LINGERING STRATUS
AT KISP/KHPN/KTEB THROUGH 16Z. A BRIEF PERIOD OF MVFR CIGS 015 TO
020 IS POSSIBLE OVER THE CITY TERMINALS THROUGH 16Z.
OTHERWISE...VFR IS EXPECTED AFTER 16Z AT ALL TERMINALS.
WITH LIGHT FLOW OVER THE AREA...WINDS HAVE VARIED. NNW-NNE WINDS
OVER CITY TERMINALS AND KHPN/KISP UNDER 10 KT WILL BECOME SW
AROUND 10 KT THIS AFTERNOON. COASTAL TERMINALS WILL BECOME SOUTH
DUE TO AFTERNOON SEA BREEZES.
WINDS DIMINISH TO 5 KT OR LESS AFT 02Z MONDAY.
FOG/STRATUS LIKELY AGAIN LATE TONIGHT THROUGH MONDAY MORNING.
.OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
.MONDAY...IFR OR LOWER IN FOG/STRATUS IN THE MORNING...THEN
PATCHY MVFR CIGS IN THE AFTERNOON. E-NE WINDS 10-15 KT.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK.
A BACKDOOR COLD FRONT APPROACHES THE WATERS FROM THE NORTH THIS
AFTERNOON AND PASSES TO SOUTH OF THE WATERS BY EARLY MONDAY
MORNING. THE PRESSURE GRADIENT GRADUALLY TIGHTENS AS HIGH PRES
BUILDS ALONG THE NEW ENGLAND COAST AND A COLD FRONT APPROACHES
FROM THE WEST. THAT FRONT MOVES ACROSS THE WATERS LATE
TUESDAY...AND THEN HIGH PRES RETURNS FOR THE MIDDLE OF THE WEEK.
SUB-SMALL CRAFT ADVISORY CONDITIONS ON TAP THROUGH MONDAY...AND
THEN SCA CONDITIONS EXPECTED ON WEDNESDAY BEHIND THE DEPARTING
COLD FRONT.
&&
.HYDROLOGY...
GENERALLY LIGHT RAINFALL AMOUNTS ARE POSSIBLE IN ANY SHOWERS THE
NEXT COUPLE OF DAYS...MAINLY WEST OF NYC.
HOWEVER...ANY SHOWERS WHICH DO FORM THIS AFTERNOON WILL BE VERY
SLOW TO MOVE. IF ANY STRONGER CONVECTION WERE TO FORM OVER A
LOCATION...THERE WOULD BE THE POTENTIAL FOR THE PONDING OF WATER
ON ROADWAYS AND POSSIBLY MINOR POOR DRAINAGE FLOODING DEPENDING ON
THE EXACT DURATION AND STRENGTH OF ANY GIVEN SHOWER WHICH MIGHT
FORM.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/DW
NEAR TERM...MALOIT/DW
SHORT TERM...DW
LONG TERM...DW/24
AVIATION...DS/MPS
MARINE...MALOIT/MPS
HYDROLOGY...MALOIT/DW
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
352 PM EDT SUN MAY 17 2015
.SYNOPSIS...
SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW AN AMPLIFIED
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. A LONGWAVE TROUGH
WITH A NOW HIGHLY NEGATIVE TILT IS PIVOTING NORTHWARD THROUGH THE
CENTRAL/NORTHERN PLAINS AND UPPER MIDWEST...WHILE DOWNSTREAM WE
FIND AMPLIFIED RIDGING OVER THE EASTERN THIRD OF THE NATION...
INCLUDING THE FL PENINSULA. THE 12Z KTBW SOUNDING SHOWS A FAIRLY
MOIST COLUMN WITH A PW VALUE OF OVER 1.5"...AND LITTLE OVERALL
RESISTANCE TO PARCEL LIFT. LOW AND MID LEVEL LAPSE RATES ARE RIGHT
AROUND 6C/KM. ONCE AGAIN...WE DO NOT SEE ANY SIGNIFICANT LAYERS OF
HOSTILE AIR TOWARD DEEP CONVECTION WITH MINIMUM THETAE VALUES
WITHIN THE 700-500MB LAYER ALL GENERALLY ABOVE 322K. THE SOUNDING
SHOWS WHAT WOULD BE EXPECTED UNDER THE MIDDLE OF A BIG UPPER
RIDGE...AND THAT IS WEAK...ALMOST VARIABLE FLOW THROUGH THE TROP
COLUMN. THIS WEAK FLOW IS GOING TO RESULT IN SLOW STORM MOTION
TODAY AS WELL. IF THE DEGREE OF THUNDERSTORM DEVELOPMENT EXPECTED
COMES TO PASS...THEN THE THREAT OF LOCALIZED FLOODING EXISTS
TODAY...ESPECIALLY IF ANY OF THE STORMS MIGRATE OVER URBAN
CENTERS.
AT THE SURFACE...ATLANTIC HIGH PRESSURE HAS SETTLED A BIT SOUTH
DURING THE PAST 24 HOURS...AND NOW RIDGES BACK WESTWARD TO NEAR
OR JUST NORTH OF THE I-10 CORRIDOR. THE RESULTING SYNOPTIC FLOW
PATTERN (1000-700MB) ACROSS OUR REGION IS 5-10 KNOTS FROM THE
E/SE.
&&
.SHORT TERM...
UPDATE (REST OF TODAY AND TONIGHT)... AS MENTIONED IN THE
SYNOPSIS OUR LARGE SCALE FLOW PATTERN IS 5-10 KNOTS FROM THE EAST
TO SOUTHEAST TODAY. THIS MODERATE SOUTHEAST FLOW IS GENERALLY OUR
MOST ACTIVE SUMMER THUNDERSTORM REGIME...AS IT BOTH TENDS TO BE
ASSOCIATED WITH A MOIST PATTERN...AND ALSO PROVIDES THE
MECHANISMS FOR ENHANCED LOW LEVEL FOCUS/CONVERGENCE ALONG THE WEST
COAST SEABREEZE. YESTERDAY...WHERE THE SEA-BREEZE WAS ABLE TO MAKE
A BIT OF SMALL PROGRESS INLAND (BASICALLY SOUTH OF TAMPA
BAY)...THIS CONVERGENCE WAS EFFICIENT AND THUNDERSTORMS ERUPTED
VERY CLOSE TO THE COAST LATE IN THE AFTERNOON. TODAY...THE FLOW
JUST ABOVE THE SURFACE APPEARS LIGHT ENOUGH TO ALLOW THIS MORE
EFFICIENT CONVERGENCE TO OCCUR ALONG MUCH...IF NOT ALL OF THE
FLORIDA WEST COAST. THEREFORE...THINK WE WILL SEE THE ACTIVE
CONVECTION EXPAND NORTHWARD THROUGH THE LATER AFTERNOON/EARLY
EVENING HOURS INTO THE TAMPA BAY AREA...AND EVEN NORTHWARD
THROUGH QUITE A BIT OF THE NATURE COAST. THE HRRR GUIDANCE THUS
FAR TODAY HAS BEEN VERY AGGRESSIVE WITH THE CONVECTION ALONG OUR
ENTIRE I-75 CORRIDOR...AND GIVEN THE FAVORABLE SYNOPTIC SETUP...SEE
LITTLE REASON TO DISAGREE WITH ITS GENERAL OUTPUT. RAIN CHANCES IN
THE 60-70% RANGE SEEM REASONABLE ALONG THE GENERAL I-75 CORRIDOR
NORTHWARD TO NEAR BROOKSVILLE... AND THEN WILL HAVE 50% FOR THE
FAR NORTHERN ZONES. BTW...THE HRRR DID A VERY GOOD JOB WITH THE
PLACEMENT AND TIMING OF THE CONVECTION ON SATURDAY...SHOWING
CONVECTIVE COVERAGE MAINLY EXTENDING FROM MANATEE COUNTY SOUTHWARD
ALONG THE COAST DURING THE MORNING RUNS. THIS VERIFIED VERY WELL.
THERE IS NOT A WHOLE LOT OF MOTION IN THE ATMOSPHERE SITTING UNDER
THE MIDDLE OF THE UPPER RIDGE...AND THEREFORE STORMS ARE NOT GOING
TO BE FAST MOVERS...PROPELLED ALONG BY WEAK FLOW...AND/OR OUTFLOW
BOUNDARY MOVEMENT. THE GENERAL MOTION SHOULD BE TOWARD THE COAST
AND EVENTUALLY OFFSHORE. HOWEVER...THE SLOW MOTION IS GOING TO
RESULT IN A HEAVY RAIN/LOCALIZED FLOODING THREAT. ALL OF THE
CONVECTION ALLOWING GUIDANCE IS SHOWING THE POTENTIAL FOR
IMPRESSIVE UPDRAFT VELOCITY VALUES AS WELL (MAXIMUM VALUES ON THE
ORDER OF 14-18M/S). THE STRONG UPDRAFTS WOULD BE CORRELATED WITH
VERY EFFICIENT LIGHTING PRODUCTION AS WELL.
ACTIVITY LINGERS INTO THE EVENING HOURS...AND MAY EVEN PEAK IN
SOME SPOTS BETWEEN 6-9PM. THEREAFTER...MOST GUIDANCE MEMBERS SHOW
THE STORMS MIGRATING OFFSHORE INTO THE EASTERN GULF AND WEAKENING.
WILL SLOWLY RAMP DOWN POPS NEAR THE COAST THROUGH THE MID/LATE
EVENING...AND RETURN ALL AREAS TO A DRY FORECAST AFTER MIDNIGHT.
THE LOW LEVEL MOISTURE WILL KEEP US SEASONABLY WARM OVERNIGHT...
WITH MOST SPOTS SEEING LOW TEMPS BY SUNRISE IN THE UPPER 60S TO
LOWER 70S.
ON MONDAY...WE ARE STILL UNDER THE UPPER RIDGE...HOWEVER THE RIDGE
AXIS BEGIN TO SHIFT WESTWARD OVER THE GULF OF MEXICO BY THE END OF
THE DAY. THE BIGGER CHANGE TO INFLUENCE OUR FORECAST WILL BE THE
CONTINUED SLOW MOVEMENT AND GENERAL WEAKENING OF THE SUBTROPICAL
ATLANTIC RIDGE. OUR FLOW LOOKS TO BECOME MUCH LIGHTER AND MORE
VARIABLE IN NATURE BY MONDAY AFTERNOON...AND THIS WILL FOR THE
FIRST TIME IN SEVERAL DAYS NOT ENHANCE FOCUS ALONG THE WEST COAST
SEA BREEZE. WE STILL EXPECT A FEW STORMS TO BUILD DURING THE
AFTERNOON HOURS...HOWEVER THE POTENTIAL COVERAGE IS MUCH LESS
THAN TODAY...AND WILL KEEP ALL AREAS AT 30-40% OR LESS FOR RAIN
CHANCES. AFTERNOON TEMPERATURES SHOULD GENERALLY RISE INTO THE
UPPER 80S TO NEAR 90...WITH LOWER TO MIDDLE 80S AT THE BEACHES
WITH THE DEVELOPING ONSHORE FLOW.
&&
.LONG TERM (TUESDAY THROUGH NEXT SUNDAY)...ALOFT - UPPER LEVEL
RIDGING INITIALLY ACROSS MUCH OF THE GULF REGION PUSHES BACK TO THE
WESTERN GULF BY MID-WEEK AS A TROUGH SWEEPS OVER THE GREAT LAKES AND
INTO THE LOWER SAINT LAWRENCE VALLEY..SAGGING DOWN THE EASTERN
SEABOARD. FOR THE LATTER HALF OF THE WEEK A PACIFIC LOW MOVES ACROSS
CA TO THE GREAT BASIN THEN OUT OVER THE CENTRAL PLAINS...AS A
TROUGH...FOR THE WEEKEND. IN RESPONSE THE WEST GULF RIDGE BUILDS
BACK INTO THE REST OF THE GULF AND OVER THE SOUTHEASTERN STATES.
SURFACE - HIGH PRESSURE SPRAWLS FROM THE NORTHERN PLAINS SOUTH TO A
FRONT THAT ARCS FROM THE GREAT LAKES THROUGH THE SOUTHERN PLAINS
THEN UP ACROSS THE INTERIOR PACIFIC NORTHWEST. ATLANTIC HIGH
PRESSURE RIDGES WEST THROUGH NORTH FL TO THE CENTRAL GULF COAST.
WITH TIME THE PLAINS HIGH PRESSURE SETTLES INTO THE MID CONUS THEN
TRACKS EAST...REACHING THE LOWER GREAT LAKES AND NORTHEAST U.S. BY
SUN. THIS WILL ADVANCE THE FRONT EAST AND SOUTH...BECOMING DIFFUSE
ACROSS THE CENTRAL GULF COAST AND NORTHERN FL. AS A RESULT THE
ATLANTIC RIDGE SAGS SOUTH OF THE STATE BY MID-WEEK THEN LIFTS BACK
NORTH FOR THE WEEKEND AND GETS REINFORCED BY THE HIGH OVER THE
NORTHEAST BRIDGING THE FRONT.
AMPLE MOISTURE...MODEL PWAT VALUES RUN 1.5 TO 1.8 INCHES...WILL
REMAIN IN PLACE FOR MOST OF THE PERIOD TO SUPPORT ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. THE EXCEPTION WILL BE AROUND
FRI WHEN SLIGHTLY DRIER AIR FILTERS IN WITH SHOWER AND STORMS
COVERAGE DECREASING SOME. AS THE SURFACE RIDGE AXIS TRAVERSES SOUTH
DURING THE EARLY PART OF THE PERIOD LOW LEVEL SOUTHEAST FLOW/ WITH
AFTERNOON SEA BREEZES/ SWITCHES TO WESTERLY THROUGH THU...WITH
SHOWERS AND STORMS FAVORING INLAND LOCATIONS. THEN WINDS VEER
THROUGH THE NORTH LATE THU AND FRI AS HIGH PRESSURE MOVES INTO THE
EASTERN CONUS AND PUSHES THE FRONT DOWN ACROSS THE STATE...WHICH
ALONG WITH THE BUILDING UPPER RIDGE EXPLAINS THE SLIGHTLY DRIER AIR
FRI. EAST AND SOUTHEAST LOW LEVEL FLOW...WITH AFTERNOON SEA
BREEZES...RETURNS FOR THE WEEKEND. TEMPERATURES WILL RUN NEAR OR
JUST ABOVE NORMAL.
&&
.AVIATION...
VFR CONDITIONS LATE THIS MORNING ACROSS WEST-CENTRAL FLORIDA.
SCT-BKN CUMULUS FIELD HAS ALREADY DEVELOPED AND WILL BE WITH US
THE REST OF THE DAY...WITH BASES RAISING FROM AROUND 3KFT TO 5KFT
THROUGH THE AFTERNOON. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
THE I-75 CORRIDOR THIS AFTERNOON AND PROGRESS WESTWARD TOWARD THE
COAST AFTER DEVELOPMENT. HAVE INCLUDED TEMPOS FOR THE EXPECTED
CONVECTION. ACTIVITY WILL PROGRESS OFFSHORE BY LATE EVENING.
&&
.MARINE...
ONSHORE WINDS ALONG THE COAST WILL SHIFT BACK TO AN EASTERLY
OFFSHORE DIRECTION BY LATER THIS EVENING. SHOWERS AND
THUNDERSTORMS THAT DEVELOP OVER THE LAND LATE TODAY WILL SHIFT
WESTWARD TOWARD THE COASTAL WATERS THROUGH THIS EVENING. BOATERS
ON THE COASTAL WATERS AND BAYS SHOULD KEEP A CLOSE WATCH ON THE
WEATHER AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY...AS STORMS
ARE LIKELY TO RAPIDLY DEVELOP AND MOVE OFFSHORE. BY TUESDAY AND
THROUGH THE REST OF THE WEEK...WIND FLOW WILL BECOME MORE
WESTERLY...AND KEEP THE MAJORITY OF THE STORMS INLAND. WINDS AND
SEAS ARE EXPECTED TO REMAIN BELOW HEADLINE CRITERIA.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE
HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. AFTER A ROUND
OF NUMEROUS THUNDERSTORMS ALONG THE I-75 CORRIDOR INTO THIS
EVENING...THE PATTERN WILL BEGIN TO CHANGE. STORMS APPEAR LESS
NUMEROUS FOR MONDAY...AND THEN WILL BE MAINLY LOCATED INLAND FROM
THE I-75 CORRIDOR DURING THE MIDDLE PORTION OF THE WEEK.
FOG IMPACT...NO SIGNIFICANT FOG IS EXPECTED FOR THE NEXT FEW
DAYS...BUT LATE NIGHT PATCHY GROUND FOG COULD DEVELOP IN AREAS
THAT SEE RAIN DURING THE EVENING HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 87 75 88 / 50 30 30 40
FMY 71 89 73 90 / 40 30 20 20
GIF 71 89 72 92 / 10 30 20 40
SRQ 72 86 73 87 / 50 20 30 20
BKV 70 89 69 90 / 40 40 20 40
SPG 75 87 75 88 / 50 30 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...14/MROCZKA
LONG TERM/DECISION SUPPORT...09/RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
256 PM CDT SUN MAY 17 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT SUN MAY 17 2015
POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING
MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE
ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF
2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT
AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL
MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS
NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING
THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE
NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH
SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN
WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM
AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED
IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO
THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END
RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG
THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT.
HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER
SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST
ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS
AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW
BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO
MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL
HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS
WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY
CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN
THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57.
&&
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 256 PM CDT SUN MAY 17 2015
COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING
SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL
COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY.
WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE
LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE
WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING
FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH
TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE
OVERNIGHT LOWS DIP INTO THE 40S.
PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY
MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA
ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY
AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK
ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND
JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER.
ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY
AND FRIDAY.
MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE
PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN
THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF
CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME
FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT
OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1238 PM CDT SUN MAY 17 2015
MAIN CONCERN WILL BE WITH CONVECTIVE CHANCES THIS AFTERNOON.
MODELS HAVE BEEN STRUGGLING TO AGREE ON WHERE EXACTLY THIS WILL
TAKE PLACE...SO WILL GENERALLY MAINTAIN THE VCTS MENTIONS WITH
JUST SOME SLIGHT ADJUSTMENTS TO TIMING BASED ON CURRENT RADAR.
HAVE INCLUDED A TEMPO PERIOD OF MVFR CONDITIONS AT KCMI/KDEC AS
THEY ARE MORE LIKELY TO SEE DEVELOPMENT FROM AN AREA OF
SHOWERS/STORMS CURRENTLY IN FAR SOUTHERN ILLINOIS. SOUTHERLY WINDS
HAVE BEEN FREQUENTLY GUSTING 25-30 KNOTS...AIDED BY SOME BREAKS IN
THE CLOUDS...BUT THESE WILL SUBSIDE A TAD THROUGH THE AFTERNOON AS
CLOUD COVER THICKENS AGAIN. HOWEVER...THE GUSTINESS WILL NOT
SUBSIDE UNTIL CLOSER TO SUNSET. WINDS EXPECTED TO DIMINISH AND
BECOME SOUTHWEST OVERNIGHT...BEFORE TRENDING MORE WESTERLY LATE IN
THE TAF PERIOD AS A COLD FRONT ARRIVES LATE MORNING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1238 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1008 AM CDT SUN MAY 17 2015
STILL QUITE A FEW QUESTIONS IN REGARDS TO SEVERE WEATHER POTENTIAL
TODAY. EARLIER LINE OF SHOWERS FIZZLED OUT AS IT PASSED I-55...
AND THE REMNANTS ARE LOCATED BETWEEN DECATUR AND CHAMPAIGN PER
LATEST RADAR IMAGERY. GOOD-SIZED CLEAR SLOT ADVANCING ACROSS THE
STATE AT THE MOMENT AND IS RESULTING IN SOME BRIEF SUNNY SKIES
OVER THE NORTHWEST HALF OF THE FORECAST AREA. THIS SHOULD HELP
DESTABILIZE THINGS ACROSS THAT AREA OVER THE NEXT HOUR OR TWO...
AND WE WILL BE DOING A SPECIAL SOUNDING AT NOON TO SAMPLE THE
CHANGES. RAP GUIDANCE SUGGESTING IT MAY TAKE UNTIL EARLY AFTERNOON
TO GET CAPE`S ABOVE 1000 J/KG FURTHER SOUTH. BEST BULK SHEAR TO BE
LOCATED WEST OF I-55...BUT LATEST RAP AND THE 12Z NAM INDICATE
THE BEST POTENTIAL FOR DEVELOPMENT WILL BE EAST OF THERE NEAR THE
REMNANTS OF THE MORNING ACTIVITY. HOWEVER...THE RECENTLY ARRIVED
14Z HRRR IS NOW STARTING TO SHOW SOME ACTIVITY MOVING UP THE
ILLINOIS RIVER VALLEY BEGINNING AROUND 3 PM. SHOWERS IN SOUTHEAST
MISSOURI STARTING TO CROSS INTO SOUTHERN ILLINOIS AS WELL...AND
ANY BOUNDARIES/VORTICES ASSOCIATED WITH THIS AREA MAY COME INTO
PLAY AS WELL.
HAVE SENT OUT SOME REFINEMENTS TO THE POP`S FOR TODAY AND TONIGHT
TO INCORPORATE THE LATEST TRENDS. LITTLE CHANGE TO HIGH
TEMPERATURE AT THE MOMENT.
&&
.SHORT TERM...(TODAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
ANOTHER UNSEASONABLY WARM & MUGGY DAY WITH SOUTHERLY WINDS IS ON TAP
FOR CENTRAL AND SOUTHEAST ILLINOIS TODAY. THIS GENERAL SCENARIO HAS
NOT CHANGED MUCH SINCE YESTERDAY. THE PRIMARY CHANGE EXPECTED FOR
TODAY IS THAT STRONGER DEEP-LAYER SHEAR WILL BE PRESENT, WITH AN
ASSOCIATED INCREASE IN ORGANIZED CONVECTION. THIS WILL BE A CHANGE
FROM THE MOSTLY DISORGANIZED SHOWERS/THUNDERSTORMS OF THE PAST
COUPLE OF DAYS. UNFORTUNATELY, THERE IS QUITE A BIT OF DISAGREEMENT
IN THE CONVECTIVE DETAILS TODAY AMONG THE GUIDANCE. DIFFERENCES ARE
NOT SURPRISING WITH THE SYNOPTIC SCALE MODELS, BUT THEY ARE ALSO
PRESENT IN THE HIGHER RESOLUTION OUTPUT AS WELL. UNDOUBTEDLY, THE
ULTIMATE OUTCOME WILL PROBABLY BE MODULATED BY BOUNDARIES FROM
UPSTREAM CONVECTION THAT MAKES IT INTO AREA AND ASSOCIATED CLOUD
COVER OR LACK THEREOF.
THE REMNANTS OF A PLAINS SQUALL LINE WILL BEGIN TO SPREAD INTO THE
WESTERN PORTION OF THE FORECAST AREA WITHIN THE NEXT COUPLE OF
HOURS. HRRR AND RAP GUIDANCE SUGGEST A RAPID WEAKENING OF THE
STORMS, AND THERE HAS BEEN SIGNIFICANT WEAKENING OF LATE IN RECENT
RADAR LOOPS, AS WELL AS WARMING CLOUD TOPS. THE REMNANTS OF THIS
SYSTEM WILL LIKELY BE KEY TO WHERE THINGS FOCUS IN THE FORECAST AREA
TODAY. MODELS HAVE CONSISTENTLY SUGGESTED CAPE VALUES FROM 1500-2500
J/KG IN THE FORECAST AREA DURING PEAK HEATING TODAY, WHILE BULK
SHEAR VALUES SHOULD BE 35-45 KTS WEST AND 25-35 KTS EAST. THESE
PARAMETERS SUGGEST SOME STRONG TO SEVERE STORMS ARE POSSIBLE IN THE
AREA TODAY, BUT THE EXACT LOCATION/TIMING OF DEVELOPMENT WILL NOT BE
A HIGH CONFIDENCE FORECAST UNTIL WE SEE HOW THINGS PLAY OUT WITH THE
REMNANTS MOVING INTO OUR AREA.
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 335 AM CDT SUN MAY 17 2015
00Z FORECAST MODELS TAKE 558 DM 500 MB LOW OVER CENTRAL NEBRASKA NE
INTO NORTHERN MN BY 12Z/MON WHILE 992 MB SURFACE LOW PRESSURE OVER
CENTRAL SD WEAKENS AS IT TRACKS NE INTO NORTHERN MN BY DAWN MONDAY.
THIS WILL BRING AN OCCLUDED FRONT EAST INTO CENTRAL IL NEAR I-55
BY 18Z/MON AND NEARING THE WABASH RIVER BY 00Z/TUE. HIGHEST
CHANCES OF SHOWERS AND THUNDERSTORMS WILL SHIFT INTO EASTERN IL
TONIGHT AND MONDAY. SPC HAS SLIGHT RISK OF SEVERE STORMS OVER ALL
BY FAR SE IL NEAR WABASH RIVER THIS AFTERNOON/EVENING WITH 15%
RISK OF LARGE HAIL AND DAMAGING WIND GUSTS AND 2-5% RISK OF
TORNADOES AND HIGHEST RISK (5%) OVER KNOX...STARK AND MARSHALL
COUNTIES. SPC KEEPS MARGINAL RISK OF SEVERE STORMS MONDAY EAST OF
IL OVER CENTRAL AND EASTERN INDIANA. MILD LOWS TONIGHT IN THE MID
TO UPPER 60S WITH SSW BREEZES. ANOTHER WARM DAY MONDAY WITH HIGHS
IN THE UPPER 70S WEST OF THE IL RIVER AND LOWER 80S EAST OF THE IL
RIVER. SW WINDS TURN WEST AND NW BEHIND COLD FRONT AND DEWPOINTS
WILL BE DROPPING BEHIND THE FRONT DURING THE DAY. THOUGH STAYING
HUMID DURING THE DAY MONDAY OVER SOUTHEAST IL WITH DEWPOINTS IN
THE UPPER 60S TO NEAR 70F.
LINGERED JUST SLIGHT CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORM IN
FAR SE IL NEAR WABASH RIVER MONDAY EVENING. OTHERWISE DRY AND COOLER
AS CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST BY TUE WITH A
FAIR AMOUNT OF SUNSHINE OVER CENTRAL/SE IL TUE WITH NW WINDS. LOWS
MON NIGHT RANGE FROM MID 40S OVER IL RIVER VALLEY TO MID 50S BY
LAWRENCEVILLE. HIGHS TUE RANGE FROM LOWER 60S NORTH OF I-74 TO
AROUND 70F BY LAWRENCEVILLE. ANOTHER COOL NIGHT TUE NIGHT WITH LOWS
IN THE MID TO UPPER 40S.
EXTENDED MODELS CONTINUE TO SHOW A DISTURBANCE EJECTING FROM THE
TROF/CUTOFF LOW NEAR CA INTO THE CENTRAL PLAINS WED AND BRINGING
MAINLY LIGHT QPF INTO CENTRAL AND SW IL WED AND SHIFTING IT
SOUTHWARD WED NIGHT AND THU. HAVE INCREASE POPS BY WED AFTERNOON TO
LIKELY FROM JACKSONVILLE SW WHILE LOWER POPS IN NE CWA BY DANVILLE.
MORE CLOUDS WED AND RAIN CHANCES TO KEEP IT COOLER WITH HIGHS IN
UPPER 50S AND LOWER 60S CENTRAL IL AND MID 60S SOUTHEAST OF I-70.
ANOTHER CANADIAN HIGH PRESSURE SETTLES INTO THE MIDWEST THU
RETURNING DRY WEATHER AND TEMPS MODERATING DUE TO MORE SUNSHINE WITH
HIGHS IN THE UPPER 60S. SEASONABLE HIGHS REACH THE LOW TO MID 70S
FRIDAY. LOOKS LIKE AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS
DURING THE MEMORIAL DAY WEEKEND ESPECIALLY FROM SAT NIGHT ON WITH
DISTURBANCE EJECTING OUT OF SW UPPER LEVEL FLOW AND INCREASING TEMPS
AND HUMIDITY WITH SOUTHERLY FLOW RETURNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1238 PM CDT SUN MAY 17 2015
MAIN CONCERN WILL BE WITH CONVECTIVE CHANCES THIS AFTERNOON.
MODELS HAVE BEEN STRUGGLING TO AGREE ON WHERE EXACTLY THIS WILL
TAKE PLACE...SO WILL GENERALLY MAINTAIN THE VCTS MENTIONS WITH
JUST SOME SLIGHT ADJUSTMENTS TO TIMING BASED ON CURRENT RADAR.
HAVE INCLUDED A TEMPO PERIOD OF MVFR CONDITIONS AT KCMI/KDEC AS
THEY ARE MORE LIKELY TO SEE DEVELOPMENT FROM AN AREA OF
SHOWERS/STORMS CURRENTLY IN FAR SOUTHERN ILLINOIS. SOUTHERLY WINDS
HAVE BEEN FREQUENTLY GUSTING 25-30 KNOTS...AIDED BY SOME BREAKS IN
THE CLOUDS...BUT THESE WILL SUBSIDE A TAD THROUGH THE AFTERNOON AS
CLOUD COVER THICKENS AGAIN. HOWEVER...THE GUSTINESS WILL NOT
SUBSIDE UNTIL CLOSER TO SUNSET. WINDS EXPECTED TO DIMINISH AND
BECOME SOUTHWEST OVERNIGHT...BEFORE TRENDING MORE WESTERLY LATE IN
THE TAF PERIOD AS A COLD FRONT ARRIVES LATE MORNING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...07/BAK
LONG TERM...07
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
110 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1257 PM CDT SUN MAY 17 2015
SEVERE RISK WHILE NOT ZERO IS QUITE LOW AND ISOLATED REST OF
TODAY...MAINLY FOCUSING NEXT HOUR FAR EASTERN CWA. CWA LARGELY
RESIDES IN BETWEEN FOCUSING MECHANISMS WITH PRESSURE PERTURBATION
AND LOW LEVEL CONVERGENCE ABOUT TO EXIT THE FAR EASTERN CWA NEXT
HOUR OR SO TAKING ANY SEVERE POTENTIAL WITH IT. 18Z DVN RAOB SHOWS
COUPLE OF CAPPING INVERSIONS AROUND OR ABOVE 800 MB IN THE WAKE
WHICH IN ABSENCE OF FORCING LOOKS TO SUPPRESS ANY ADDITIONAL
DEVELOPMENT. EXCEPTION BEING NORTHWEST CWA WHICH COULD SEE SOME
ACTIVITY DEVELOP OR PROPAGATE INTO LATE THIS AFTERNOON AND EVENING
FROM CENTRAL/WESTERN IA ATTENDANT TO VORT MAX AND COLDER POCKET OF
AIR ROTATING IN ALOFT. STRONG SHEAR AND DRY AIR ALOFT MAY HARBOR
SOME POTENTIAL FOR GUSTY WINDS AND HAIL WITH ANY OF THIS ACTIVITY.
&&
.SYNOPSIS...
ISSUED AT 340 AM CDT SUN MAY 17 2015
SYNOPSIS...HUGE SQUALL LINE OF SEVERE STORMS AND EMBEDDED TORNADOES
EXTENDED ALL THE WAY FROM NORTHERN MO TO CENTRAL TX. HOWEVER...THE
FAR NORTHERN PORTION OF THE LINE APPROACHING NORTHEAST MO AND
SOUTHCENTRAL IA WAS RAPIDLY WEAKENING AS IT RUNS INTO MUCH MORE
STABLE AIR WITH MINIMAL CAPE. ALSO...IR SATELLITE SHOWS RAPIDLY
WARMING TOPS. MEANWHILE BACK AT THE RANCH...LOW STRATUS HAS FORMED
OVER MUCH OF THE CWA DUE TO CONTINUED MOISTURE TRANSPORT FROM THE
SOUTH. 3 AM TEMPERATURES RANGED FROM THE MID 60S TO AROUND 70 WITH
DEWPOINTS IN THE MID 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SUN MAY 17 2015
FORECAST FOCUS ON SEVERE POTENTIAL AND COVERAGE OF THUNDERSTORMS.
TODAY...SPC HAS SHIFTED THE ENHANCED SEVERE RISK NORTH OF THE CWA
CLOSER TO THE STRONGEST SHEAR AND TRIPLE POINT OF THE OCCLUDING
CYCLONE WITH A SLIGHT RISK OVER ALL OF THE CWA. SPC HAS A 5%
PROBABILITY FOR TORNADOES IN NORTHEAST IA AND NORTHERN IL WITH A 15%
PROBABILITY OF WIND AND HAIL OVER THE ENTIRE CWA. THIS IS A LOW
CONFIDENCE FORECAST OF EXACTLY HOW THE CONVECTION WILL PLAY OUT AS
MODELS DIFFER GREATLY...RANGING FROM NUMEROUS TO ONLY ISOLATED
STORMS.
FIRST OF ALL IS THIS MORNING WITH THE RAPIDLY DECAYING SQUALL LINE
WHICH WILL BE MOVING INTO OUR WESTERN AND SOUTHERN CWA EARLY THIS
MORNING...SO WILL HAVE LIKELY POPS FOR THOSE AREAS. THE HRRR MODEL
TAKES THIS WEAK LINE OVER ALL OF EASTERN IA TO ABOUT THE MS RIVER
THEN FADES IT BY MID MORNING...SO WILL HAVE CHANCE POPS THE FARTHER
EAST YOU GO INTO THE CWA. THEN WE HAVE THE LOW STRATUS FOR MUCH OF
THE MORNING WITH THE AVIATION GFS-LAMP GUIDANCE INDICATING THIS TO
DISSIPATE BY LATE MORNING/EARLY AFTERNOON SIMILAR TO YESTERDAY.
THIS AFTERNOON...COVERAGE OF THUNDERSTORMS IS PROBLEMATIC AS MODELS
HAVE DIFFERING SOLUTIONS. MODELS STILL INDICATE STRONG DEEP LAYER
SHEAR WITH 0-6KM OF 40-45 KTS AIDED BY CYCLONICALLY CURVED JET FROM
MID MISSISSIPPI VALLEY INTO GREAT LAKES. TEMPERATURES IN THE LOWER
TO MID 80S AND DEWPTS IN THE MID TO UPPER 60S SHOULD YIELD MODERATE
INSTABILITY WITH MLCAPES OF 1000-2000 J/KG. THIS IS CERTAINLY
SUFFICIENT TO SUPPORT ALL MODES OF SEVERE WEATHER. HOWEVER...WITH
THE OCCLUDING CYCLONE WE ARE ALSO LOSING THE FORCING/LOW LEVEL
CONVERGENCE TO GET STORMS TO DEVELOP...EXCEPT IN OUR FAR EASTERN
COUNTIES EARLY THIS AFTERNOON. THIS WILL BE INTERESTING TO SEE HOW
THIS PLAYS OUT BUT FOR NOW WILL HAVE THE HIGHEST POPS IN THE EAST
AND ONLY SLIGHT POPS IN THE SW. MAXIMUM TEMPERATURES SHOULD GET INTO
THE LOWER TO MID 80S AT MOST LOCATIONS.
TONIGHT...I WILL MAINTAIN THE SMALL POPS FOR EARLY THIS EVENING
ALONG AND EAST OF THE MS RIVER BUT WE COULD JUST AS EASILY BE DRY.
OPERATIONAL MODELS INDICATE DRY SLOT TO SPREAD OVER ALL THE CWA AS
THE OCCLUDING CYCLONE TRACKS INTO THE MN ARROWHEAD. SKIES WILL BE
CLEARING OR CLEAR WITH COOLER AND DRIER AIR BEGINNING TO PUSH INTO
THE NW CWA OVERNIGHT. MINIMUM TEMPERATURES WILL RANGE FROM THE MID
50S NW TO THE LOWER TO MID 60S SE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN MAY 17 2015
COOL BUT NICE MID MAY WEATHER FOR THE UPCOMING WORK WEEK WITH SOME
LIGHT RAIN POSSIBLE WEDNESDAY.
LONG TERM FORECAST CONFIDENCE ASSESSMENT...GOOD OR ABOVE AVERAGE WITH
LITTLE SENSIBLE WEATHER ISSUES. MAIN ISSUE IS DIURNAL TEMPERATURE RANGES
WITH MOST DAYS SUGGESTION OF WIDER RANGES OF HI/LO BY A DEGREE OR SO
MOST LOCATIONS SUPPORTED.
OVERVIEW...INITIALIZATION AND VERIFICATION IS GOOD WITH SLIGHTLY TOO
MOIST BL ISSUES NOTED THAT ARE IMPACTING NORMAL MODEL FIELDS CURRENTLY
AS TOO WIDESPREAD EXCEPT FOR LINEAR FEATURES UNDERDONE. THIS WILL HAVE
NO IMPACT MONDAY ONWARD. RUN TO RUN VARIANCES SUGGEST LITTLE DIFFERENCES
EXCEPT TEMPERATURES BY A CATEGORY OR SO WITH A MEAN TAKEN FOR LATER
SHIFTS TO REASSESS AS AGAIN PROBABLE A DEGREE OR TWO TO COOL/MILD FOR
HIGHS/LOWS MOST DAYS.
MONDAY...STRONG CAA TO RESULT IN BREEZY WEATHER WITH MANY LOCATIONS
TO HAVE NEARLY STEADY TEMPERATURES WITH 15 TO 25+ MPH WITH SOME GUSTS
TO 30 MPH NORTH HALF OF FORECAST AREA. STRONG GRADIENT WITH LOWER 60S
FAR NW TO UPPER 70S FAR SE SECTIONS. MONDAY NIGHT...WINDS MAY BE UP
ENOUGH TO PRECLUDE FROST RISK WITH UPPER 30S NW TO MID 40S SOUTH SECTIONS.
TUESDAY...BELOW NORMAL TEMPERATURES BY 10 TO 15 DEGREES WITH CONTINUED
CAA WITH LOW LEVEL THERMAL FIELDS SUPPORTIVE OF NEAR 60F FAR NORTH TO
MIDDLE 60S SOUTH SECTIONS DESPITE NEARLY FULL TO FULL SUNSHINE.
TUESDAY NIGHT...LIGHT WINDS MAY ALLOW FOR BL DECOUPLING NORTH 1/2
AND PATCHY FROST RISK FOR LATER SHIFT TO RECONSIDER. LOCAL TECHNIQUES
DO SUGGEST WITH FAIR SKIES AND BL DECOUPLING SOME MID 30S POSSIBLE
ALONG AND NORTH OF HIGHWAY 30 CORRIDOR FAVORED LOW LYING LOCATIONS.
WEDNESDAY...INCREASING CLOUDS WITH RISK OF SPRINKLES MOSTLY CENTRAL
SECTIONS AND SOME LIGHT RAIN SOUTH 1/3 OF AREA. HIGHS SHOULD WITH CLOUDS
BE MOSTLY LOWER 60S WITH UPPER 50S POSSIBLE IN HEAVIEST CLOUDS AND
POSSIBLE LIGHT RAIN. WEDNESDAY NIGHT...ANY LIGHT PRECIPITATION SHOULD
END AROUND MIDNIGHT WITH CLEARING SKIES BY MORNING ALL BUT FAR SE
SECTIONS. MINS LOWER TO MIDDLE 40S ARE REASONABLE.
THURSDAY THROUGH SATURDAY...MORE NICE WEATHER WITH UPPER 60S MOST LOCATIONS
FOR HIGHS ON THURSDAY AND LOWER 70S A GOOD REFERENCE POINT FRIDAY/SATURDAY
WITH LOW DEWPOINTS. MINS 40S RISING INTO THE 50S SATURDAY AND SUNDAY
AM WITH PROBABLE MOST LOCATIONS MINS ARE 2 TO 3 PLUS DEGREES TOO MILD
FOR LATER SHIFTS TO CONSIDER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1238 PM CDT SUN MAY 17 2015
GENERALLY VFR CONDITIONS EXPECTED THROUGH THE TAF CYCLE. LOW CONFIDENCE
ON ANY SHOWER OR STORM DEVELOPMENT THIS AFTERNOON AND EARLY
EVENING...WITH FAVORED AREAS MAINLY EAST OF TERMINALS AHEAD OF WEAK
PRESSURE PERTURBATION AND LOW LEVEL CONVERGENCE...AND ALSO WEST OF THE
TERMINALS WITH COLDER AIR ALOFT ROTATING AROUND NORTHERN PLAINS
UPPER LOW. GUSTY SOUTHERLY WINDS 15-30 KTS WILL DIMINISH TO AROUND 10 KTS
THIS EVENING AND VEER TO WESTERLY OVERNIGHT WITH COLD FRONTAL PASSAGE.
WINDS WITH MIXING TO BECOME GUSTY AGAIN ON MONDAY AT 15-30 KTS FROM THE
WEST/NORTHWEST.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...05
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...NICHOLS
AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1247 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 715 AM CDT SUN MAY 17 2015
ONLY A FEW SHOWERS WERE NOTED ON RADAR IN THE DVN CWA AND MOST OF
THOSE WERE OCCURING IN OUR FAR WESTERN COUNTIES. I HAVE REMOVED
THE MENTION OF THUNDER THROUGH THE MID MORNING HOURS AT LEAST.
OTHERWISE...EXTENSIVE CLOUD COVER WILL BE SEEN THIS MORNING. THE
LATEST MESO MODEL RUNS INDICATE MUCH OF THE CWA TO REMAIN DRY
TODAY SO CONFIDENCE REMAINS LOW WITH REGARD TO THE COVERAGE OF
CONVECTION.
&&
.SYNOPSIS...
ISSUED AT 340 AM CDT SUN MAY 17 2015
SYNOPSIS...HUGE SQUALL LINE OF SEVERE STORMS AND EMBEDDED TORNADOES
EXTENDED ALL THE WAY FROM NORTHERN MO TO CENTRAL TX. HOWEVER...THE
FAR NORTHERN PORTION OF THE LINE APPROACHING NORTHEAST MO AND
SOUTHCENTRAL IA WAS RAPIDLY WEAKENING AS IT RUNS INTO MUCH MORE
STABLE AIR WITH MINIMAL CAPE. ALSO...IR SATELLITE SHOWS RAPIDLY
WARMING TOPS. MEANWHILE BACK AT THE RANCH...LOW STRATUS HAS FORMED
OVER MUCH OF THE CWA DUE TO CONTINUED MOISTURE TRANSPORT FROM THE
SOUTH. 3 AM TEMPERATURES RANGED FROM THE MID 60S TO AROUND 70 WITH
DEWPOINTS IN THE MID 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SUN MAY 17 2015
FORECAST FOCUS ON SEVERE POTENTIAL AND COVERAGE OF THUNDERSTORMS.
TODAY...SPC HAS SHIFTED THE ENHANCED SEVERE RISK NORTH OF THE CWA
CLOSER TO THE STRONGEST SHEAR AND TRIPLE POINT OF THE OCCLUDING
CYCLONE WITH A SLIGHT RISK OVER ALL OF THE CWA. SPC HAS A 5%
PROBABILITY FOR TORNADOES IN NORTHEAST IA AND NORTHERN IL WITH A 15%
PROBABILITY OF WIND AND HAIL OVER THE ENTIRE CWA. THIS IS A LOW
CONFIDENCE FORECAST OF EXACTLY HOW THE CONVECTION WILL PLAY OUT AS
MODELS DIFFER GREATLY...RANGING FROM NUMEROUS TO ONLY ISOLATED
STORMS.
FIRST OF ALL IS THIS MORNING WITH THE RAPIDLY DECAYING SQUALL LINE
WHICH WILL BE MOVING INTO OUR WESTERN AND SOUTHERN CWA EARLY THIS
MORNING...SO WILL HAVE LIKELY POPS FOR THOSE AREAS. THE HRRR MODEL
TAKES THIS WEAK LINE OVER ALL OF EASTERN IA TO ABOUT THE MS RIVER
THEN FADES IT BY MID MORNING...SO WILL HAVE CHANCE POPS THE FARTHER
EAST YOU GO INTO THE CWA. THEN WE HAVE THE LOW STRATUS FOR MUCH OF
THE MORNING WITH THE AVIATION GFS-LAMP GUIDANCE INDICATING THIS TO
DISSIPATE BY LATE MORNING/EARLY AFTERNOON SIMILAR TO YESTERDAY.
THIS AFTERNOON...COVERAGE OF THUNDERSTORMS IS PROBLEMATIC AS MODELS
HAVE DIFFERING SOLUTIONS. MODELS STILL INDICATE STRONG DEEP LAYER
SHEAR WITH 0-6KM OF 40-45 KTS AIDED BY CYCLONICALLY CURVED JET FROM
MID MISSISSIPPI VALLEY INTO GREAT LAKES. TEMPERATURES IN THE LOWER
TO MID 80S AND DEWPTS IN THE MID TO UPPER 60S SHOULD YIELD MODERATE
INSTABILITY WITH MLCAPES OF 1000-2000 J/KG. THIS IS CERTAINLY
SUFFICIENT TO SUPPORT ALL MODES OF SEVERE WEATHER. HOWEVER...WITH
THE OCCLUDING CYCLONE WE ARE ALSO LOSING THE FORCING/LOW LEVEL
CONVERGENCE TO GET STORMS TO DEVELOP...EXCEPT IN OUR FAR EASTERN
COUNTIES EARLY THIS AFTERNOON. THIS WILL BE INTERESTING TO SEE HOW
THIS PLAYS OUT BUT FOR NOW WILL HAVE THE HIGHEST POPS IN THE EAST
AND ONLY SLIGHT POPS IN THE SW. MAXIMUM TEMPERATURES SHOULD GET INTO
THE LOWER TO MID 80S AT MOST LOCATIONS.
TONIGHT...I WILL MAINTAIN THE SMALL POPS FOR EARLY THIS EVENING
ALONG AND EAST OF THE MS RIVER BUT WE COULD JUST AS EASILY BE DRY.
OPERATIONAL MODELS INDICATE DRY SLOT TO SPREAD OVER ALL THE CWA AS
THE OCCLUDING CYCLONE TRACKS INTO THE MN ARROWHEAD. SKIES WILL BE
CLEARING OR CLEAR WITH COOLER AND DRIER AIR BEGINNING TO PUSH INTO
THE NW CWA OVERNIGHT. MINIMUM TEMPERATURES WILL RANGE FROM THE MID
50S NW TO THE LOWER TO MID 60S SE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN MAY 17 2015
COOL BUT NICE MID MAY WEATHER FOR THE UPCOMING WORK WEEK WITH SOME
LIGHT RAIN POSSIBLE WEDNESDAY.
LONG TERM FORECAST CONFIDENCE ASSESSMENT...GOOD OR ABOVE AVERAGE WITH
LITTLE SENSIBLE WEATHER ISSUES. MAIN ISSUE IS DIURNAL TEMPERATURE RANGES
WITH MOST DAYS SUGGESTION OF WIDER RANGES OF HI/LO BY A DEGREE OR SO
MOST LOCATIONS SUPPORTED.
OVERVIEW...INITIALIZATION AND VERIFICATION IS GOOD WITH SLIGHTLY TOO
MOIST BL ISSUES NOTED THAT ARE IMPACTING NORMAL MODEL FIELDS CURRENTLY
AS TOO WIDESPREAD EXCEPT FOR LINEAR FEATURES UNDERDONE. THIS WILL HAVE
NO IMPACT MONDAY ONWARD. RUN TO RUN VARIANCES SUGGEST LITTLE DIFFERENCES
EXCEPT TEMPERATURES BY A CATEGORY OR SO WITH A MEAN TAKEN FOR LATER
SHIFTS TO REASSESS AS AGAIN PROBABLE A DEGREE OR TWO TO COOL/MILD FOR
HIGHS/LOWS MOST DAYS.
MONDAY...STRONG CAA TO RESULT IN BREEZY WEATHER WITH MANY LOCATIONS
TO HAVE NEARLY STEADY TEMPERATURES WITH 15 TO 25+ MPH WITH SOME GUSTS
TO 30 MPH NORTH HALF OF FORECAST AREA. STRONG GRADIENT WITH LOWER 60S
FAR NW TO UPPER 70S FAR SE SECTIONS. MONDAY NIGHT...WINDS MAY BE UP
ENOUGH TO PRECLUDE FROST RISK WITH UPPER 30S NW TO MID 40S SOUTH SECTIONS.
TUESDAY...BELOW NORMAL TEMPERATURES BY 10 TO 15 DEGREES WITH CONTINUED
CAA WITH LOW LEVEL THERMAL FIELDS SUPPORTIVE OF NEAR 60F FAR NORTH TO
MIDDLE 60S SOUTH SECTIONS DESPITE NEARLY FULL TO FULL SUNSHINE.
TUESDAY NIGHT...LIGHT WINDS MAY ALLOW FOR BL DECOUPLING NORTH 1/2
AND PATCHY FROST RISK FOR LATER SHIFT TO RECONSIDER. LOCAL TECHNIQUES
DO SUGGEST WITH FAIR SKIES AND BL DECOUPLING SOME MID 30S POSSIBLE
ALONG AND NORTH OF HIGHWAY 30 CORRIDOR FAVORED LOW LYING LOCATIONS.
WEDNESDAY...INCREASING CLOUDS WITH RISK OF SPRINKLES MOSTLY CENTRAL
SECTIONS AND SOME LIGHT RAIN SOUTH 1/3 OF AREA. HIGHS SHOULD WITH CLOUDS
BE MOSTLY LOWER 60S WITH UPPER 50S POSSIBLE IN HEAVIEST CLOUDS AND
POSSIBLE LIGHT RAIN. WEDNESDAY NIGHT...ANY LIGHT PRECIPITATION SHOULD
END AROUND MIDNIGHT WITH CLEARING SKIES BY MORNING ALL BUT FAR SE
SECTIONS. MINS LOWER TO MIDDLE 40S ARE REASONABLE.
THURSDAY THROUGH SATURDAY...MORE NICE WEATHER WITH UPPER 60S MOST LOCATIONS
FOR HIGHS ON THURSDAY AND LOWER 70S A GOOD REFERENCE POINT FRIDAY/SATURDAY
WITH LOW DEWPOINTS. MINS 40S RISING INTO THE 50S SATURDAY AND SUNDAY
AM WITH PROBABLE MOST LOCATIONS MINS ARE 2 TO 3 PLUS DEGREES TOO MILD
FOR LATER SHIFTS TO CONSIDER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1238 PM CDT SUN MAY 17 2015
GENERALLY VFR CONDITIONS EXPECTED THROUGH THE TAF CYCLE. LOW CONFIDENCE
ON ANY SHOWER OR STORM DEVELOPMENT THIS AFTERNOON AND EARLY
EVENING...WITH FAVORED AREAS MAINLY EAST OF TERMINALS AHEAD OF WEAK
PRESSURE PERTURBATION AND LOW LEVEL CONVERGENCE...AND ALSO WEST OF THE
TERMINALS WITH COLDER AIR ALOFT ROTATING AROUND NORTHERN PLAINS
UPPER LOW. GUSTY SOUTHERLY WINDS 15-30 KTS WILL DIMINISH TO AROUND 10 KTS
THIS EVENING AND VEER TO WESTERLY OVERNIGHT WITH COLD FRONTAL PASSAGE.
WINDS WITH MIXING TO BECOME GUSTY AGAIN ON MONDAY AT 15-30 KTS FROM THE
WEST/NORTHWEST.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...NICHOLS
AVIATION...05
AREA FORECAST DISCUSSION
NWS JACKSON KY
300 PM EDT SUN MAY 17 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN MAY 17 2015
THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER
AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING
IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE
ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS
THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR
SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM
FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE
FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND
SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY
WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH
0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING
OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY
QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE
OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND
STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON
MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE
DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK
HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL
ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH
CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS
BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO
INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN
THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND
TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN MAY 17 2015
MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL
PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE
WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY
NIGHT INTO EARLY THURSDAY.
IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48
HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND
ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST
COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH
PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND
AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A
RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF
THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A
DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING
BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION.
A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE
IN THE WEEK...DY6 FRI.
THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE
DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY
THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE
WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING
MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS.
THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY
DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF
THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE
END OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 127 PM EDT SUN MAY 17 2015
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS
EASTERN KENTUCKY TO BEGIN THE TAF PERIOD. BY 18 OR 19Z WE SHOULD
SEE MORE WIDESPREAD ACTIVITY...WITH EACH OF THE TAF SITES SEEING
THE POSSIBILITY OF SHOWERS AND STORMS THROUGH AROUND 23Z THIS
AFTERNOON. MVFR AND POSSIBLY IFR CONDITIONS WILL BE POSSIBLE
WHENEVER A SHOWER OR STORM DIRECTLY AFFECTS A TAF SITE. SCT TO BKN
CLOUD COVER WILL ALSO BE ON TAP THROUGHOUT THE PERIOD. SOME VALLEY
FOG WILL ALSO BE POSSIBLE BETWEEN 6 AND 13Z MONDAY...BUT NONE OF
THIS SHOULD AFFECT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AR
LONG TERM...AR
AVIATION...AR
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
455 PM CDT SUN MAY 17 2015
.DISCUSSION...
MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS
OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW
LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR
WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH
OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING
WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN
TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL-
DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS
PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS
EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS
SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING
MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW
HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE
DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT
WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE
REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE
DIFFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE
SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE
VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD
DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE
AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE
EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW
AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH
THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS
AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z
MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN
SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE
OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT.
HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH
MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0
INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE.
AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN
NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE
TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE
HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD
DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY
SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY.
THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS
AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH
THE MAIN ATTENDENT TROUGH LIFTING NE INTO THE SRN ROCKIES BY EARLY
TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH WILL
HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE SRN
PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH THE
FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT TERM
PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING SW
INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING STATIONARY.
PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE GFS...WHICH
SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS ALOFT TO HELP
DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP FOCUS SCT
CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER ISOLATED TO
WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE
INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK
PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT
SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT
BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS
ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO
ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR
WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE
REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY.
HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF
THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING
THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION
DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT
BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE
CLIMO THROUGH MUCH OF THE PERIOD.
PRELIMS TO FOLLOW BELOW...
15
&&
.PREV DISCUSSION... /ISSUED 101 PM CDT SUN MAY 17 2015/
AVIATION...
BAND OF CONVECTION THIS MORNING MOVG ACROSS AREA FROM THE
WEST...HAS BECOME SCATTERED IN VCNTY OF KLFK...KSHV...KMLU...AND
KELD...AND HAS JUST MOVD EAST OF KTXK...KGGG...AND KTYR. BRIEF IFR
VSBYS MAY OCCUR IN VERY HEAVY RAIN...OTHERWISE...EXPECT VFR
CONDITIONS THRU AT LEAST 18/04Z. AIRMASS LIKELY TOO STABLE THIS
AFTN IN WAKE OF THIS CONVECTION FOR REDEVELOPMENT WITH AFTN
HEATING. NEXT CONVECTIVE BAND PROGGED TO ENTER CWA LATE THIS EVE
ACROSS NE TX...BECMG MORE WIDESPREAD LATER TONIGHT AS IT MOVES
ACROSS LA/AR PORTIONS OF AREA. LIGHT TO SOUTHERLY WINDS AROUND 10
KTS CAN BE EXPECTED THRU PERIOD. /VII/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 71 82 70 86 / 70 70 30 30
MLU 72 81 69 86 / 60 70 30 40
DEQ 68 83 67 82 / 60 40 30 30
TXK 70 83 68 83 / 70 50 30 30
ELD 70 81 68 84 / 70 70 30 30
TYR 71 82 69 85 / 60 50 20 30
GGG 70 82 69 86 / 70 60 20 30
LFK 72 82 71 88 / 40 70 20 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR ARZ050-051-059>061-070>073.
LA...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR LAZ001>006-010>012.
OK...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR OKZ077.
TX...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR TXZ096-097-108>112-124>126-136>138-149>153.
&&
$$
15
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1231 PM CDT SUN MAY 17 2015
.DISCUSSION...
18Z TAF ISSUANCE.
&&
.AVIATION...
S WINDS ~14-17 KTS WITH GUSTS AROUND 25 KTS OR HIGHER EXPECTED
THIS AFTERNOON AS THE PRESSURE GRADIENT REMAINS TIGHT WITH HIGH
PRESSURE OFF THE EAST COAST AND LOW PRESSURE TROF OVER THE CENTRAL
PLAINS. RADAR SHOWS SCT SHRA/TSRA ACROSS SE TX/C LA...WITH THE
HIGHEST CHANCES FOR AEX/BPT/LCH AT 40-50% THIS AFTERNOON...SLIGHTLY
LESS CHANCES AT LFT/ARA...BUT STILL EXPECTING AROUND 30%. FOR
THIS...TEMPO GROUP FOR INTERMITTENT TSRA & MVFR CEILINGS FROM
18-22Z AT AEX/BPT/LCH. FOR THIS EVENING...ONLY VCSH EXPECTED
AFTER THE LOSS OF DAYTIME HEATING. EXPECT MVFR CEILINGS BY
06Z...WITH INTERMITTENT IFR CEILINGS FROM 10-14Z MON.
DML
&&
.PREV DISCUSSION... /ISSUED 1021 AM CDT SUN MAY 17 2015/
UPDATE...
IR SATELLITE SHOWING SOME CLOUD TOP WARMING PERHAPS SIGNALING AN
OVERALL WEAKENING TREND IN A LINE OF SHOWERS AND THUNDERSTORMS
NOTED ON RADAR THIS MORNING ALONG A TOMBALL...HUNSTVILLE...LUFKIN
TX LINE. INSTABILITY IS APPARENT AHEAD OF THIS LINE AS SCATTERED
SHOWERS ARE DEVELOPING ACROSS INTERIOR SOUTHEAST TEXAS EXTENDING
SOUTHWEST INTO THE HOUSTON AREA.
CURRENT FORECAST ON TRACK AS POPS IN LINE WHERE CONVECTION IS
DEVELOPING AND IS FORECAST TO CONTINUE TO DEVELOP MOSTLY ACROSS
OUR NORTHERN AREAS. SOUTHERN AREAS ALONG AND SOUTH OF I-10
CORRIDOR WILL SEE A SLIGHT CHANCE OF AFTERNOON CONVECTION BUT
BELIEVE MID AND HIGH CLOUDS MAY LIMIT ANYTHING MORE.
NO CHANGES FOR ZONE FORECAST PACKAGE. 06
PREV DISCUSSION... /ISSUED 701 AM CDT SUN MAY 17 2015/
DISCUSSION...
17/12Z TAF ISSUANCE.
AVIATION...
OTHER THAN SOME SHRA EAST OF THE LOWER ATCHAFALAYA BASIN...KLCH
88D SHOWS LITTLE CONVECTION ACRS THE AREA THIS MORNING. WIDESPREAD
LOW CLOUDS WITH BKN CIGS PREVAILING BETWEEN 1000-2000 FT. EXPECT
CIGS TO LIFT TO VFR THROUGH MIDDAY WITH SCT CONVECTION DEVELOPING
AS DAYTIME HEATING INTERACTS WITH A PASSING DISTURBANCE ALOFT AND
AN APPROACHING SFC BOUNDARY OVER TX. GUSTY SLY WINDS CAN AGAIN BE
EXPECTED.
CURRENTLY...A LINE OF STORMS EXTENDS FM NE TX SW TO THE RIO
GRANDE VALLEY. THIS LINE WILL APPROACH SE TX LATER THIS MORNING
AND COULD AFFECT BPT BY MIDDAY IF IT HOLDS TOGETHER. BOTH THE NAM
AND HRRR INDICATE THE NRN END OF THE LINE SHOULD REACH PORTIONS OF
NRN/CNTL LA AS WELL...THUS INCLUDED TEMPO GROUPS AT BOTH AEX AND
BPT. INSERTED PROB30 AFTER 21Z FOR LCH WITH VC AT LFT/ARA AS
UNCERTAINTY INCREASES REGARDING CONVECTIVE EVOLUTION THROUGH THE
AFTN. ACTIVITY SHOULD DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING...WITH MVFR CIGS RETURNING AFTER MIDNIGHT. 24
PREV DISCUSSION... /ISSUED 343 AM CDT SUN MAY 17 2015/
DISCUSSION...
WATER VAPOR CURRENTLY SHOWING SOME DRIER AIR AND SUBSIDENCE ALOFT
ACROSS THE FORECAST AREA...AND LOCAL RADARS ARE ON THE QUIET SIDE
OVER THE IMMEDIATE FORECAST AREA...WITH JUST AN OCCASIONAL LIGHT
POP-UP NOCTURNAL SHOWER.
THE THINKING FOR THE PAST COUPLE OF DAYS HAD BEEN THAT SUNDAY
WOULD SEE LESS ACTIVITY BASED ON THE SOMEWHAT DRIER AIR IN THE MID
LEVELS AND FORECAST AREA WOULD BE BETWEEN SYSTEMS.
HOWEVER...REGIONAL RADAR IMAGES SHOW CLUSTERS OF THUNDERSTORMS
ALONG A LINE EXTENDING FROM THE RED RIVER VALLEY THROUGH CENTRAL
TEXAS JUST WEST OF I-35. THIS ACTIVITY IS NOTED ALONG A SURFACE
TROUGH WITH ENERGY FROM AN UPPER LEVEL DISTURBANCE AT IT KICKS
OUT. PROGS...ESPECIALLY THE LATEST HRRR...IS RATHER BULLISH WITH
KEEPING ACTIVITY TOGETHER AND REACHING THE NORTHERN PORTIONS OF
THE FORECAST AREA THIS AFTERNOON. THEREFORE...WILL HAVE HIGH END
CHANCE FOR SHOWERS AND STORMS ACROSS UPPER SOUTHEAST TEXAS...AND
NORTH OF HIGHWAY 190 IN LOUISIANA...FOR THIS AFTERNOON...WITH LOW
END CHANCE SOUTH OF THIS LINE TO THE COAST. THE MAIN HAZARD WILL
BE LOCALLY HEAVY RAINFALL AND OCCASIONAL TO FREQUENT CLOUD TO
GROUND LIGHTNING.
ACTIVITY THAT DEVELOPS WILL DECREASE IN THE EVENING HOURS WITH THE
LOSS OF DAYTIME HEATING.
AS THE UPPER LEVEL TROUGH CONTINUES TO KICK OFF TO THE NORTHEAST
ON MONDAY...IT WILL PUSH A SURFACE TROUGH INTO THE FORECAST AREA
WHERE IT WILL STALL ROUGHLY ALONG HIGHWAY 190 AND WASH OUT ON
TUESDAY. THE COMBINATION OF A VERY MOIST ENVIRONMENT AND LIFT FROM
THE TROUGH...WILL PRODUCE DECENT RAIN CHANCES...ESPECIALLY
NORTHERN ZONES ON MONDAY INTO TUESDAY...WITH THE BEST CHANCE
DURING THE AFTERNOON...ALTHOUGH ACTIVITY COULD DEVELOP DURING ANY
PART OF THE DAY. CLOUD COVER MAY LIMIT INSTABILITY...ALONG WITH
UPPER LEVEL ENERGY ON THE MODEST SIDE...AND THIS MAY KEEP STORMS
IN CHECK...WITH AGAIN THE MAIN CONCERNS THE HEAVY RAINFALL
POTENTIAL...WITH PWAT BETWEEN 1.8 AND 2 INCHES...AND MEAN RH IN
THE 70 TO 80 PERCENT RANGE.
THE SURFACE BOUNDARY WILL WASH-OUT BY WEDNESDAY...AND WEAK FLAT
UPPER LEVEL RIDGING WILL TRY TO BUILD INTO THE FORECAST AREA.
STILL...PLENTY OF MOISTURE WITH SOUTH FLOW OFF THE GULF. MAIN
KICKER WILL BE DAYTIME HEATING...SO WILL HAVE TYPICAL SUMMERTIME
CONVECTION TYPE POPS FOR THE REMAINDER OF THE FORECAST TO COVER
DIURNAL DRIVEN STORMS.
RUA
MARINE...
MODERATE SOUTHEAST FLOW OCCURRING OVER THE COASTAL WATERS THIS
EARLY MORNING WITH NOCTURNAL LOW LEVEL JET AND INFLOW INTO TROUGH
AND COMPLEX OF STORMS OVER THE RED RIVER VALLEY INTO CENTRAL
TEXAS. SUSTAINED WINDS AT TIMES NEAR 20 KNOTS...AND PROGS SHOW
THIS CONTINUING THROUGH THE MORNING HOURS...UNTIL TROUGH GETS
CLOSER TO THE REGION. THEREFORE...WILL EXTEND SMALL CRAFT EXERCISE
CAUTION THROUGH THE MORNING HOURS.
WINDS AWAY FROM CONVECTION WILL DECREASE LATER THIS AFTERNOON INTO
MONDAY AS SURFACE TROUGH NEARS THE FORECAST AREA...LESSENING THE
GRADIENT ACROSS THE COASTAL WATERS. THIS SURFACE TROUGH WILL STALL
AND WASH OUT NORTH OF THE COASTAL WATERS LATE MONDAY INTO TUESDAY.
THEREFORE...WITH HIGH PRESSURE AT THE SURFACE ANCHORED OFF THE
SOUTHEAST U.S. COAST...SOUTH TO SOUTHEAST WINDS WILL PREVAIL AT
LIGHT TO OCCASIONALLY MODERATE LEVELS THROUGH THE FORECAST PERIOD.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE LATER TODAY AND
MONDAY...WITH UNSTABLE CONDITIONS PREVAILING INTO TUESDAY...AS THE
TROUGH INTERACTS WITH THE MOIST ENVIRONMENT TO PRODUCE SCATTERED
SHOWERS AND THUNDERSTORMS...ESPECIALLY NEAR SHORE OR OVER THE
COASTAL LAKES. WINDS AND SEAS WILL BE LOCALLY HIGHER NEAR THE
STORMS. THE CONVECTION WILL DECREASE IN COVERAGE FOR THE MIDDLE TO
LATE PART OF THE WEEK.
RUA
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 73 85 70 86 / 20 60 40 50
LCH 76 87 74 86 / 20 40 20 40
LFT 75 87 73 86 / 20 50 30 40
BPT 76 88 74 86 / 20 40 20 30
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AVIATION...08
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
530 PM EDT SUN MAY 17 2015
.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL CONTINUE UNTIL PASSAGE OF A
TUESDAY COLD FRONT.
&&
.NEAR TERM /THROUGH MONDAY/...
EARLY EVENING UPDATE CENTERED REALLY AROUND LOW LEVEL MOISTURE AND
ITS RAMIFICATIONS FOR THE REST OF THE EVENING AND OVERNIGHT.
PREVIOUS FORECAST COVERED DIURNALLY-DRIVEN SHOWERS/THUNDERSTORMS
WITH LITTLE UPPER SUPPORT FAIRLY WELL...AND STILL SEEMS A-OK.
HOWEVER...LOW LEVEL MOISTURE VIA DEWPOINTS ACROSS OHIO IS ACTUALLY
A BIT STRONGER THAN DEPICTED ON ANY MODEL SOLUTION THIS
EVENING...INCLUDING THE HRRR. DEWPOINTS ACROSS THE BULK OF OHIO
ARE RUNNING IN THE UPPER 60S TO LOWER 70S...AND EVEN IN
PENNSYLVANIA AND WEST VIRGINIA...MID TO UPPER 60S ARE FAIRLY
PREVALENT. GIVEN POOR MIXING AND WEAK CONVECTIVE
OVERTURNING...ALONG WITH WET SOIL FROM RAIN THIS MORNING IN MOST
LOCATIONS...IT WOULD SEEM WE ARE WELL PRIMED FOR FOG DEVELOPMENT
OVERNIGHT. GIVEN BUFKIT SOUNDINGS FROM THE NAM OVER MOST OF THE
AREA EXCEPT MAYBE OUR WESTERNMOST COUNTIES IN OHIO...DECOUPLING
AND STABILIZATION OF THE BOUNDARY LAYER SHOULD LEAD TO SOME FOG
OVERNIGHT. FARTHER WEST TOWARD ZANESVILLE...THE ONLY THING THAT
MAY INHIBIT THIS WOULD BE SOME PRE-FRONTAL TROUGH MIXING OVERNIGHT
TOWARD MORNING. TO ACCOUNT FOR ALL OF THIS...AREAS OF FOG WERE
CARRIED MOST EVERYWHERE OVERNIGHT...EXCEPT AROUND
ZANESVILLE...WHERE JUST PATCHY FOG WAS CARRIED.
OTHERWISE...THE PREVIOUS FORECAST HANDLES THE SLOW DEMISE OF
THUNDERSTORMS INTO ISOLATED SHOWERS OVERNIGHT WITH FAIRLY STABLE
TEMPERATURES IN THE MID AND UPPER 60S. FRIES
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS PRE-FRONTAL TROUGH SHIFTS EAST MONDAY EVENING IT WILL TAKE MOST
OF THE DEEP MOISTURE WITH IT. POPS WILL BE IN THE CHANCE CATEGORY
AFTER MONDAY EVENING AS MAIN FRONT PUSHES EAST EARLY TUESDAY. DEW
POINTS WILL REMAIN A BIT ELEVATED UNTIL FRONT AND UPPER LEVEL
TROUGH PASS TUESDAY AFTERNOON. MUCH COOLER AND DRIER AIR FOR
TUESDAY NIGHT AND WEDNESDAY AS SURFACE HIGH PRESSURE BUILDS
ACROSS REGION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODEL GUIDANCE CONTINUES TO SUGGEST A PROLONGED PERIOD OF DRY
WEATHER...WITH TEMPERATURES CLOSE TO OR JUST BELOW SEASONAL
AVERAGES INTO LATE WEEK.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
CONDITIONS WILL CONTINUE TO BOUNCE AROUND HIGH END MVFR/LOW END VFR
THIS AFTERNOON AS CONVECTION DEVELOPS WITH SURFACE HEATING AND
DESTABILIZATION. SHOWERS AND THUNDERSTORMS ARE ALREADY EXPANDING
ACROSS CENTRAL OHIO AND WEST VIRGINIA EARLY THIS AFTERNOON AND WILL
LIKELY IMPACT AT LEAST ZZV AND MGW PER THE LATEST HI RES GUIDANCE.
THUS...HAVE MENTIONED VCTS AT THOSE PORTS. WHILE SOME STORMS MAY
MAKE IT FURTHER NORTH AND EAST...THE LATEST HRRR TRIES TO KEEP THE
BULK OF STORMS SOUTH OF PIT SO GENERALLY MAINTAINED VCSH THIS
EVENING AS CONVECTION DIMINISHES WITH LOSS OF HEATING. ANY TAF THAT
IS IMPACTED BY A STORM THIS AFTERNOON AND EVENING WILL EXPERIENCE
BRIEF IFR CONDITIONS IN HEAVY RAIN BUT OPTED TO LEAVE THIS OUT OF
ANY PARTICULAR SITE FOR NOW.
THE UPPER RIDGE WILL BUILD OVERNIGHT...BUT DESPITE LIGHT WINDS
CONFIDENCE IN THE EXTENT OF FOG STRATUS THAT WOULD DEVELOP REMAINS
LOW. THUS...MAINTAINED GENERAL MVFR TOWARD SUNRISE WITH IMPROVEMENT
MONDAY MORNING.
.OUTLOOK.../MONDAY NIGHT THROUGH THURSDAY/...
PERIODIC CONVECTION AND RESULTING RESTRICTIONS ARE POSSIBLE UNTIL
PASSAGE OF A TUESDAY COLD FRONT.&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
256 PM EDT SUN MAY 17 2015
.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL CONTINUE UNTIL PASSAGE OF A
TUESDAY COLD FRONT.
&&
.NEAR TERM /THROUGH MONDAY/...
WITH EXIT OF UPPER LEVEL WAVE SCATTERED DIURNAL CONVECTION HAS
DEVELOPED ACROSS MOST OF THE REGION AND WILL CONTINUE UNTIL AFTER
SUNSET. LEFT ISOLATED SHOWERS IN OVERNIGHT WITH HIGH DEW POINTS
AND DEEP MOISTURE...A STRAY SHOWER WILL BE POSSIBLE.
FOR MONDAY A PRE-FRONTAL TROUGH WILL MOVE INTO AND ACROSS THE
REGION WITH THE BEST OPPORTUNITY FOR WIDESPREAD SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON. SPC HAS A MARGINAL THREAT OF
SEVERE...WITH PLENY OF LOW LEVEL INSTABILITY BUT UPPER LEVEL
SUPPORT LACKING. TEMPERATURES THROUGH MONDAY JUST A BIT ABOVE
MODEL MOS WITH HIGH DEW POINTS TONIGHT...AND POSSIBLY A BIT MORE
SUNSHINE MONDAY.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS PRE-FRONTAL TROUGH SHIFTS EAST MONDAY EVENING IT WILL TAKE MOST
OF THE DEEP MOISTURE WITH IT. POPS WILL BE IN THE CHANCE CATEGORY
AFTER MONDAY EVENING AS MAIN FRONT PUSHES EAST EARLY TUESDAY. DEW
POINTS WILL REMAIN A BIT ELEVATED UNTIL FRONT AND UPPER LEVEL
TROUGH PASS TUESDAY AFTERNOON. MUCH COOLER AND DRIER AIR FOR
TUESDAY NIGHT AND WEDNESDAY AS SURFACE HIGH PRESSURE BUILDS
ACROSS REGION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODEL GUIDANCE CONTINUES TO SUGGEST A PROLONGED PERIOD OF DRY
WEATHER...WITH TEMPERATURES CLOSE TO OR JUST BELOW SEASONAL
AVERAGES INTO LATE WEEK.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
CONDITIONS WILL CONTINUE TO BOUNCE AROUND HIGH END MVFR/LOW END VFR
THIS AFTERNOON AS CONVECTION DEVELOPS WITH SURFACE HEATING AND
DESTABILIZATION. SHOWERS AND THUNDERSTORMS ARE ALREADY EXPANDING
ACROSS CENTRAL OHIO AND WEST VIRGINIA EARLY THIS AFTERNOON AND WILL
LIKELY IMPACT AT LEAST ZZV AND MGW PER THE LATEST HI RES GUIDANCE.
THUS...HAVE MENTIONED VCTS AT THOSE PORTS. WHILE SOME STORMS MAY
MAKE IT FURTHER NORTH AND EAST...THE LATEST HRRR TRIES TO KEEP THE
BULK OF STORMS SOUTH OF PIT SO GENERALLY MAINTAINED VCSH THIS
EVENING AS CONVECTION DIMINISHES WITH LOSS OF HEATING. ANY TAF THAT
IS IMPACTED BY A STORM THIS AFTERNOON AND EVENING WILL EXPERIENCE
BRIEF IFR CONDITIONS IN HEAVY RAIN BUT OPTED TO LEAVE THIS OUT OF
ANY PARTICULAR SITE FOR NOW.
THE UPPER RIDGE WILL BUILD OVERNIGHT...BUT DESPITE LIGHT WINDS
CONFIDENCE IN THE EXTENT OF FOG STRATUS THAT WOULD DEVELOP REMAINS
LOW. THUS...MAINTAINED GENERAL MVFR TOWARD SUNRISE WITH IMPROVEMENT
MONDAY MORNING.
.OUTLOOK.../MONDAY NIGHT THROUGH THURSDAY/...
PERIODIC CONVECTION AND RESULTING RESTRICTIONS ARE POSSIBLE UNTIL
PASSAGE OF A TUESDAY COLD FRONT.&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
328 PM EDT SUN MAY 17 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 326 PM EDT SUN MAY 17 2015
A STRONG STORM FOR THIS TIME OF YEAR WILL TRACK TOWARD WESTERN
LAKE SUPERIOR BY MONDAY MORNING AND THEN INTO CENTRAL ONTARIO BY
TUESDAY MORNING. THAT WILL CAUSE A STRONG COLD FRONT TO COME
THROUGH THIS AREA MONDAY AFTERNOON. SCATTERED SHOWER AND
THUNDERSTORMS ARE EXPECTED EARLY TONIGHT WELL AHEAD OF THE COLD
FRONT. THEN IT WILL TURN BREEZY AND MUCH COLDER MONDAY NIGHT AND
TUESDAY. HIGHS WILLS STRUGGLE TO MAKE 50 TUESDAY AND THERE COULD
BE A FROST AND FREEZING TEMPERATURES BY WEDNESDAY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 326 PM EDT SUN MAY 17 2015
I CONTINUE TO BELIEVE THE RISK FOR STRONG TO SEVERE STORMS IS
RATHER LIMITED TONIGHT. THE BEST DYNAMICS ARE TO OUR WEST AND
NORTH...CLOSER TO THE SYSTEM OVER MINNESOTA AND WISCONSIN. THE
LATEST RUN OF THE RAP MODEL (18Z) CONTINUES TO SHOW THE LOW LEVEL
JET CORE TRACKING THROUGH WESTERN WISCONSIN THIS EVENING LEAVING
SOUTHWEST MICHIGAN IN THE SPEED AREA BEHIND THAT JET. ALSO THE
BEST UPPER DIVERGENCE ASSOICATED WITH THE POLAR JET CORE IS EASILYOVER
WISCONSIN. WHILE THERE IS A SIGIFNCIANT AMOUNT OF MIXED LAYER CAPE
THIS EVENING THE LACK OF DYNAMICS WILL RESULT IN THE BEST STORMS
STAYING OVER WISCONSIN. EVEN SO SOME SHOWERS AND THUNDERSTORMS WILL
TRACK THROUGH OUR EASTERN CWA LATE THIS AFTERNOON THEN ANOTHER
AREA WILL TRACK THROUGH OUR CENTRAL AND EASTER COUNTIES AFTER 8PM
BUT I DO NOT EXPECT ANY SEVERE STORMS AT THIS TIME.
DRY AIR MOVES IN MONDAY THEN MUCH COLDER AIR MOVES IN BEHIND THE
SYSTEM FOR MONDAY NIGHT INTO TUESDAY NIGHT. THERE IS NOT ENOUGH
MOISTURE FOR SHOWERS IN THE COLD AIR MONDAY NIGHT OR TUESDAY. WE
MAY WILL HAVE FREEZING TEMPEATURES AND WIDESPEAD FROST TUESDAY
NIGHT AS SKIES CLEAR.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 326 PM EDT SUN MAY 17 2015
MUCH OF THE EXTENDED PERIOD WILL BE COOL AND DRY...BUT WE SHOULD SEE
A WARM UP BY THE WEEKEND...ALONG WITH A CHANCE OF SHOWERS AND STORMS
RETURNING SATURDAY NIGHT AND SUNDAY.
AN UPPER LOW OVER JAMES BAY WILL KEEP US COOL WITH A NORTHWEST UPPER
FLOW. H8 TEMPS WED THROUGH FRI REMAIN IN THE +1 TO +4C RANGE...
KEEPING DAYTIME HIGH TEMPS BELOW NORMAL...MAINLY IN THE LOW AND MID
60S. THERE SHOULD BE A BACK DOOR COLD FRONT COME THROUGH THURSDAY
NIGHT...BUT IT APPEARS DRY...JUST SUPPLYING A EXTRA SHOT OF COOL AIR
INTO FRIDAY.
A WARM UP SHOULD COMMENCE SATURDAY AS AN UPPER RIDGE BEGINS TO
BUBBLE TOWARD THE AREA PUSHING THE NW FLOW EAST. TEMPS SHOULD
RETURN TO NEAR NORMAL VALUES. RAIN CHANCES WILL RETURN SATURDAY
NIGHT OR SUNDAY AS A WARM FRONT LIFTS NORTH ACROSS IN/OH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 148 PM EDT SUN MAY 17 2015
A MIX OF VFR AND MVFR CEILINGS WERE OVER THE REGION AS OF 17Z.
THIS IS EXPECTED TO TREND TO MORE VFR AS CEILINGS GRADUALLY LIFT
THIS AFTERNOON. FOR THE MOST PART VFR CONDITIONS WILL PREVAIL
THEREAFTER INTO MID DAY MONDAY.
INSTABILITY AND MOISTURE WAS INCREASING ACROSS THE AREA AND
SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO DEVELOP AFTER 20Z.
STORMS SHOULD REMAIN SCATTERED ACROSS THE AREA THROUGH ABOUT 09Z
TONIGHT WHEN DRIER AIR ARRIVES. A COLD FRONT WILL PASS THROUGH SW
MI MONDAY AFTERNOON BUT AT THIS POINT IS APPEAR IT WILL PASS
THROUGH MAINLY DRY AS THE DEEPEST MOISTURE RACES EAST...WELL AHEAD
OF IT. LEFT ANY MENTION OF SHOWERS/STORMS OUT OF THE TAFS AFTER
09Z.
SOUTHERLY WINDS WILL GUST TO AROUND 20 KNOTS THROUGH THIS
EVENING...THEN BECOMING SOUTHWEST LATE TONIGHT AT 10-15 KTS.
&&
.MARINE...
ISSUED AT 326 PM EDT SUN MAY 17 2015
I CONTINUED THE FOG ADVIOSRY AS WEB CAMS DO SHOW SOME FOG YET.
WE WILL LIKELY NEED A SMALL CRAFT ADVISORY MONDAY NIGHT AND
TUESDAY AS THE COLD AIR COMES IN.
&&
.HYDROLOGY...
ISSUED AT 1210 AM EDT SUN MAY 17 2015
THE MAIN THREAT THROUGH THE NEXT 24 HOURS WILL BE THE POSSIBILITY
FOR LOCALIZED HEAVY RAINFALL.
A MAJORITY OF THE AREA STREAMS AND RIVERS ARE RUNNING WELL BELOW
ADVISORY LEVELS WITH A COUPLE OF SITES SLIGHTLY BELOW. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP AND TRAVEL EAST OUT OF THE
UPPER MIDWEST THIS EVENING AND INTO TONIGHT. AREA AVERAGE
RAINFALL MAY RUN FROM A FEW TENTHS OF AN INCH UPWARDS OF A HALF
INCH. LOCALIZED HEAVY POCKETS WILL CREATE GREAT VARIATIONS IN
RAINFALL TOTALS IN SHORT DISTANCES. LOCATIONS THAT ARE AFFECTED BY
HEAVIER RAINFALL MAY EXPERIENCE LOCALIZED PONDING OR TEMPORARY
STREET FLOODING WITH SMALL CREEK AND STREAM FLUCTUATIONS
POSSIBLE. LARGER RIVERS ARE EXPECTED TO REMAIN BELOW ACTION
STAGE THROUGH THE PERIOD AS FEEDBACK TIMES WILL TAKE US INTO
DRIER WEATHER FOR THE UPCOMING WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...DENSE FOG ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...JK
AVIATION...JK
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
148 PM EDT SUN MAY 17 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 315 AM EDT SUN MAY 17 2015
A WARM FRONT WILL LIFT NORTH TODAY PUTTING SOUTHERN LOWER MICHIGAN
IN AN INCREASINGLY WARM AND HUMID AIRMASS. AN ISOLATED SHOWER OR
STORM IS POSSIBLE TODAY WITH A MUCH BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON AND EVENING. A STRONG COLD
FRONT WILL MOVE THROUGH MONDAY BRINGING A CONTINUED CHANCE FOR A
SHOWER OR THUNDERSTORM. MUCH COOLER WEATHER WILL MOVE IN TUESDAY
THROUGH MIDWEEK.
&&
.UPDATE...
ISSUED AT 1129 AM EDT SUN MAY 17 2015
I CURRENTLY REMAIN UNIMPRESSED ON THE CHANCE OF SEVERE STORMS
LATE THIS AFTERNOON AND THIS EVENING. THE RAP AND NAM FROM THE
LATEST MODEL RUNS HAVE TO CORE OF THE LOW LEVEL JET GOING OVER
NORTHERN LAKE MICHIGAN INTO THE UPPER PENINSULA BETWEEN 4 PM AND
MIDNIGHT. THAT PUTS SOUTHWEST MICHIGAN IN THE SPEED DIVERGENCE
AREA OF THE LOW LEVEL JET (NOT GOOD FOR SEVERE STORMS). THE UPPER
DIVERGENCE FROM THE UPPER LEVEL JET CORE IS OVER THE LOW LEVEL
JET MAX (NORTHERN WISCONSIN) THIS AFTERNOON AND EVENING...NOT
OVER SOUTHWEST MICHIGAN. THE DEEP LAYER SHEAR GREATER THAN 35
KNOTS IS MOSTLY WEST OF US-131 AND NORTH OF MKG THIS AFTERNOON AND
EVENING...REALLY IT IS OVER WISCONSIN (40 TO 60 KNOTS). THE SPC
ENSEMBLE 09Z HAS THE 30 TO 40 PERCENT CHANCE FOR SEVERE STORMS
OVER WISCONSIN THIS AFTERNOON AND EVENING...MEANWHILE A 10 PERCENT
AREA DOES GET INTO WESTERN LOWER MICHIGAN WEST OF US-131 FROM 4 PM
TILL 8 PM. ALL OF THIS TELL ME THE RISK FOR SEVERE STORMS OVER
SOUTHWEST MICHIGAN WOULD BE VERY LOW. STILL IT IS NOT ZERO SO WE
WILL HAVE TO WATCH AS CONDITIONS DEVELOP THIS AFTERNOON AND
EVENING.
OVERALL OUR BEST CHANCE FOR THUNDERSTORMS IS THIS EVENING. I HAVE
NOT SIGNIFICANTLY CHANGED OUR FORECAST IN THAT WAY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 315 AM EDT SUN MAY 17 2015
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
PROBABILITIES FOR CONVECTION TODAY THROUGH MONDAY.
THE AIRMASS OVER OUR FCST AREA WILL BECOME INCREASINGLY WARM AND
HUMID TODAY AS A WARM FRONT GRADUALLY MOVES NORTH OF OUR AREA.
THERE IS JUST A SMALL CHANCE OF AN ISOLATED SHOWER OR THUNDERSTORM
BUT MOST OF OUR AREA WILL STAY DRY THIS MORNING THROUGH MOST OF
THE AFTERNOON.
00Z 4KM WRF-NMM SIM Z GUIDANCE AND THE NSSL WRF SUGGEST THAT
SHOWERS AND THUNDERSTORMS ARE LIKELY TO DEVELOP ACROSS OUR AREA
LATE THIS AFTERNOON THROUGH THE EVENING. CONVECTIVE DEVELOPMENT LATE
THIS AFTERNOON AND EARLY EVENING WILL BE AIDED BY WEAK TO MODERATE
INSTABILITY WITH POTENTIAL FOR SB CAPE VALUES TO REACH AROUND
1000-2000 J/KG.
SHOWERS AND STORMS LATE THIS EVENING WILL BE AIDED BY FORCING
FROM A 35 TO 40 KT LLJ AND STRONG 1000-850 MB MOISTURE TRANSPORT.
A FEW SHOWERS OR ISOLATED STORMS MAY LINGER VERY LATE TONIGHT BUT
THE MOST LIKELY TIME FRAME FOR CONVECTION SEEMS TO BE FROM AROUND
21Z THIS AFTERNOON THROUGH 06Z TONIGHT.
CONVECTIVE POTENTIAL FOR MONDAY IS LARGELY CONTINGENT ON EXACT
COLD FRONTAL TIMING. A CONSENSUS OF LATEST GUIDANCE SUGGESTS THAT
THE BETTER CHANCE FOR STORMS WILL LIKELY STAY SE OF OUR FCST
AREA... BUT THAT SOME SHOWERS AND STORMS MAY REDEVELOP MAINLY OVER
OUR SE FCST AREA PRIOR TO FROPA.
SHORT RANGE GUIDANCE CONTINUES TO SUGGEST SOME WEAK TO MODERATE
INSTABILITY WILL DEVELOP JUST AHEAD OF THE FRONT SO THIS WILL NEED
TO BE MONITORED SINCE FORCING FROM THE FRONT WILL BE STRONG.
HOWEVER IF FRONT MOVES THROUGH FASTER AS SUGGESTED BY THE 00Z GFS
THEN ALL OF OUR FCST AREA SHOULD STAY DRY MONDAY.
IT WILL TURN BREEZY BEHIND THE FRONT MONDAY NIGHT THROUGH TUESDAY
WITH STRONG NW FLOW CAA. MAX TEMPS TUESDAY WILL ONLY REACH THE
50S.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM EDT SUN MAY 17 2015
THREAT OF FROST EXISTS ON TUESDAY NIGHT AS COLD DRY AIR MASS SETTLES
INTO THE REGION FROM THE NORTH. HOWEVER THERE IS STILL SOME QUESTION
AS TO HOW QUICK THE SFC RIDGE BUILDS IN AND WHETHER OR NOT THE WINDS
DIE OFF. EXTENT OF CLEARING IS ALSO UNCERTAIN AT THIS TIME.
OTHERWISE A RATHER QUIET/UNEVENTFUL LONG TERM PERIOD EXPECTED WITH
SURFACE RIDGING AND RELATIVELY COOL DRY AIR MASS DOMINATING OUR
WEATHER. THIS PATTERN SHOULD RESULT IN A DECENT AMOUNT OF SUNSHINE
ALONG WITH LARGE DIURNAL TEMPERATURES SWINGS. EXPECT COOL NIGHTS AND
GENERALLY PLEASANT DAYS WITH LOW HUMIDITIES AND HIGHS MODERATING A
FEW DEGREES EACH DAY.
ONE THING TO WATCH HOWEVER IS THE POTENTIAL FOR CONSIDERABLE MID AND
HIGH CLOUDS AND EVEN SOME SPRINKLES ON WEDNESDAY RELATED TO A SYSTEM
PASSING BY JUST TO OUR SOUTH IN THE ZONAL FLOW. THEN...THE NORTHWEST
FLOW ALOFT ON THURSDAY AND FRIDAY COULD ALSO LEAD TO SOME BRIEF
PERIODS OF THICKER CLOUDS AND SPRINKLES AS WEAK FAST MOVING
SHORTWAVES OCCASIONALLY DROP THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 148 PM EDT SUN MAY 17 2015
A MIX OF VFR AND MVFR CEILINGS WERE OVER THE REGION AS OF 17Z.
THIS IS EXPECTED TO TREND TO MORE VFR AS CEILINGS GRADUALLY LIFT
THIS AFTERNOON. FOR THE MOST PART VFR CONDITIONS WILL PREVAIL
THEREAFTER INTO MID DAY MONDAY.
INSTABILITY AND MOISTURE WAS INCREASING ACROSS THE AREA AND
SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO DEVELOP AFTER 20Z.
STORMS SHOULD REMAIN SCATTERED ACROSS THE AREA THROUGH ABOUT 09Z
TONIGHT WHEN DRIER AIR ARRIVES. A COLD FRONT WILL PASS THROUGH SW
MI MONDAY AFTERNOON BUT AT THIS POINT IS APPEAR IT WILL PASS
THROUGH MAINLY DRY AS THE DEEPEST MOISTURE RACES EAST...WELL AHEAD
OF IT. LEFT ANY MENTION OF SHOWERS/STORMS OUT OF THE TAFS AFTER
09Z.
SOUTHERLY WINDS WILL GUST TO AROUND 20 KNOTS THROUGH THIS
EVENING...THEN BECOMING SOUTHWEST LATE TONIGHT AT 10-15 KTS.
&&
.MARINE...
ISSUED AT 315 AM EDT SUN MAY 17 2015
WE HAVE EXTENDED THE MARINE DENSE FOG ADVISORY THROUGH TONIGHT
SINCE A VERY WARM AND HUMID AIRMASS WILL CONTINUE TO ADVECT IN
OVER RELATIVELY COLD LAKE WATERS AND RESULT IN AREAS OF DENSE FOG.
SOUTHERLY WINDS WILL INCREASE SOMEWHAT THIS AFTERNOON THROUGH
TONIGHT RESULTING IN GRADUALLY INCREASING WAVE HEIGHTS. HOWEVER
WINDS AND WAVE HEIGHTS WILL STAY BELOW SMALL CRAFT CRITERIA
THROUGH TONIGHT. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS LATE
THIS AFTERNOON AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 1210 AM EDT SUN MAY 17 2015
THE MAIN THREAT THROUGH THE NEXT 24 HOURS WILL BE THE POSSIBILITY
FOR LOCALIZED HEAVY RAINFALL.
A MAJORITY OF THE AREA STREAMS AND RIVERS ARE RUNNING WELL BELOW
ADVISORY LEVELS WITH A COUPLE OF SITES SLIGHTLY BELOW. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP AND TRAVEL EAST OUT OF THE
UPPER MIDWEST THIS EVENING AND INTO TONIGHT. AREA AVERAGE
RAINFALL MAY RUN FROM A FEW TENTHS OF AN INCH UPWARDS OF A HALF
INCH. LOCALIZED HEAVY POCKETS WILL CREATE GREAT VARIATIONS IN
RAINFALL TOTALS IN SHORT DISTANCES. LOCATIONS THAT ARE AFFECTED BY
HEAVIER RAINFALL MAY EXPERIENCE LOCALIZED PONDING OR TEMPORARY
STREET FLOODING WITH SMALL CREEK AND STREAM FLUCTUATIONS
POSSIBLE. LARGER RIVERS ARE EXPECTED TO REMAIN BELOW ACTION
STAGE THROUGH THE PERIOD AS FEEDBACK TIMES WILL TAKE US INTO
DRIER WEATHER FOR THE UPCOMING WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...DENSE FOG ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...JAM
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1243 PM EDT SUN MAY 17 2015
.AVIATION...
EXPECT LOWER CLOUDS TO PERSIST BUT MIX OUT OF MVFR INTO LOW END VFR
DURING THE AFTERNOON. THIS WILL OCCUR UNDER A MORE UNIFORM SOUTH
WIND OVER THE TERMINAL CORRIDOR AS THE WARM FRONT PUSHES FARTHER
INTO NORTHERN LOWER MICHIGAN. THE POTENTIAL FOR SHOWERS WILL
INCREASE AS THE TEMPERATURE PUSHES 80 DURING THE LATE AFTERNOON
AND LASTING THROUGH THE EVENING. THE RAINFALL PATTERN WILL BE
ENHANCED TONIGHT BY A BROAD SWATH OF DEEPER MOISTURE MOVING IN ON
THE LEADING EDGE OF A STRONGER WAVE ALOFT. THIS DEEPER MOISTURE
WILL THEN MOVE EASTWARD BY SUNRISE. A STRONGER SOUTH WIND WILL
REDUCE THE FOG POTENTIAL MONDAY MORNING COMPARED TO THE LAST
COUPLE OF DAYS BUT IFR/MVFR CEILING IN STRATUS LOOKS LIKELY
INSTEAD.
FOR DTW... A SHOWER OR THUNDERSTORM COULD OCCUR NEAR THE LAKE ERIE
SHORELINE DURING THE LATE AFTERNOON. THIS WILL BE MONITORED BEFORE
INCLUSION IN THE FORECAST BEFORE A MORE LIKELY PERIOD OF SHOWERS
ARRIVES TONIGHT.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CIG BELOW 5000 FEET TODAY AND TONIGHT.
* LOW FOR A THUNDERSTORM TODAY AND TONIGHT.
&&
.PREV DISCUSSION...ISSUED 1113 AM EDT SUN MAY 17 2015
UPDATE...
FOG LIFTED INTO LOW STRATUS DURING MID MORNING AND SOME OF THE
STRATUS MIXED OUT INTO POCKETS OF CLEAR SKY DURING LATE MORNING.
THE LATEST SATELLITE TREND INDICATES THE CLEAR POCKETS QUICKLY
FILLING IN WITH SHALLOW CU OVER THE MOIST BOUNDARY LAYER HAVING
DEWPOINT GENERALLY IN THE MID 60S. EXPECT THIS WILL CONTINUE WITH
NO BETTER THAN PARTLY SUNNY/BROKEN SKY THROUGH THE REST OF THE
DAY. THE MOIST BOUNDARY LAYER ALSO MAINTAINS A STAGE FOR SCATTERED
SHOWERS/ORDINARY STORMS AS CONDITIONS WARM TO CONVECTIVE
TEMPERATURE IN THE UPPER 70S. SURFACE ANALYSIS PLACES THE WARM
FRONT MOSTLY NORTH OF OUR AREA AND ATTEMPTING TO MAKE PROGRESS
INTO THE MID LAKE HURON MARINE LAYER. THERE COULD BE SOME
SHORELINE LAKE BREEZE BOUNDARIES TO FOCUS DEVELOPMENT LEAVING WARM
SECTOR SURFACE HEATING TO MAX TEMPS IN THE LOWER 80S NEEDED FOR
DEVELOPMENT ELSEWHERE. THE BEST CHANCE OF ACTIVITY WILL ACCOMPANY
THE PRIMARY THETA-E RIDGE BUILDING IN FROM ILLINOIS AND INDIANA
DURING LATE AFTERNOON INTO THIS EVENING.
PREV DISCUSSION...ISSUED 359 AM EDT SUN MAY 17 2015
SHORT TERM...TODAY AND TONIGHT
LIGHT WINDS...BREAKS IN THE CLOUDS...AND RAINFALL YESTERDAY HAVE ALL
SET THE STAGE FOR FOG AND STRATUS TO FORM ONCE AGAIN THIS MORNING.
SO FAR VISIBILITIES HAVE PREDOMINANTLY RANGED FROM 1-5 MILES. THE
ARRIVAL OF ADDITIONAL CLOUDS SHOULD HELP PREVENT WIDESPREAD DENSE
FOG...BUT PATCHES ARE CERTAINLY POSSIBLE. WILL CONTINUE TO MONITOR
DENSE FOG POTENTIAL THROUGH THE MORNING HOURS HOWEVER.
UPPER RIDGE STILL REMAINS OVER THE SOUTHEAST CONUS...WITH LOWER
MICHIGAN POSITIONED ON THE WESTERN PERIPHERY. THE RIDGE AXIS WILL
SHIFT EAST TODAY AS THE LARGE UPPER TROUGH OVER THE CENTRAL U.S.
BEGINS TO LIFT TOWARDS THE UPPER MIDWEST. THE INFLUENCE OF THE RIDGE
WILL CONTINUE TO PROVIDE A STABILIZING INFLUENCE OVER THE AREA
THROUGH THE MORNING HOURS...WITH THERMAL PROFILES ON GFS/NAM
FORECAST SOUNDINGS STILL SHOWING WEAK LAPSE RATES IN THE MID-LEVELS
ASSOCIATED WITH THE WARMER AIR ALOFT. POTENTIAL FOR CONVECTION
THROUGH THE EARLY PART OF THE DAY LOOKS LIMITED THEREFORE...BUT
STILL POSSIBLE ALONG A FEW FEATURES. FRONTAL BOUNDARY REMAINS DRAPED
ACROSS CENTRAL LOWER MICHIGAN AS OF 300 AM THIS MORNING. THIS FRONT
WILL LIFT NORTHWARD THROUGH THE LATE MORNING AS SOUTHERLY FLOW
INCREASES AHEAD OF THE APPROACHING UPPER TROUGH. THE FRONT COULD
PROVIDE A FOCUS THIS MORNING FOR A FEW SHOWERS OR EVEN A TSTORM TO
FORM OVER THE SAGINAW VALLEY AND THUMB. FURTHER SOUTH IN THE WARM
SECTOR...UPPER SHORTWAVE MOVING EAST THROUGH THE OHIO VALLEY COULD
TRIGGER A FEW SHOWERS/TSTORMS NEAR THE BORDER.
AIRMASS WILL REMAIN VERY MOIST TODAY/TONIGHT WITH DEWPOINTS IN THE
60S. TEMPERATURES IN THE MID-LEVELS WILL MEANWHILE COOL SLIGHTLY
THROUGH THE DAY AS THE UPPER RIDGE AXIS PULLS EAST...WHILE THE
SURFACE LAYER HEATS TO AROUND 80F THIS AFTERNOON. AS THIS
OCCURS...WILL SEE INSTABILITY INCREASE THROUGH THE DAY AND BECOME
SURFACE BASED...WITH A PARCEL OF 80/65 YIELDING ABOUT 1000 J/KG OF
CAPE DURING THE LATE AFTERNOON. SEVERE WEATHER IS NOT EXPECTED
THROUGH LATE AFTERNOON AS SHEAR VALUES LOOK UNIMPRESSIVE AND CAPE
LOOKS TALL/SKINNY. VERY HEAVY DOWNPOURS WILL CONTINUE TO BE POSSIBLE
AS PW VALUES RISE FROM 1.5 INCHES THIS MORNING TO AROUND 1.75 INCHES
TONIGHT. WILL NEED TO FIND A TRIGGER FOR CONVECTION IN THE WARM
SECTOR TODAY/TONIGHT IN ORDER TO GET ANYTHING OTHER THAN JUST A FEW
CELLS POPPING UP HOWEVER. LOOKING BACK AT OBSERVATIONAL AND MODEL
DATA OVER THE CONUS FROM YESTERDAY...IT APPEARS AN OLD WARM FRONT
WAS CAST OFF THE SYSTEM OVER THE SOUTHERN/CENTRAL PLAINS EARLY
YESTERDAY. CURRENT OBSERVATIONS OVER SOUTEHRN ILLINOIS/INDIANA DO
INDICATE A SLIGHT "KINK" IN THE FLOW. THIS IS WHERE NAM/GFS MODELS
CURRENTLY PLACE THIS FEATURE...AND THEY BOTH LIFT IT THROUGH
SOUTHEAST MICHIGAN BETWEEN 14-22Z (PER THERMAL FIELDS AND HIGHER
THETA-E ADVECTION). COVERAGE OF SHOWERS/TSTORMS THAT COULD DEVELOP
AS THIS SUBTLE FEATURE WORKS THROUGH IS UNCERTAIN HOWEVER AS THE
ATMOSPHERE REMAINS JUICY BUT NOT OVERLY BUOYANT. KEPT COVERAGE AT
CHANCE AS HIGHER-RES RUNS OF THE 4KM WRF AND THE HRRR DO NOT SEEM
TOO KEEN ON WIDESPREAD CONVECTION DEVELOPING UNDER THE MORE STABLE
INFLUENCE OF THE RIDGE DEPARTING TO OUR EAST.
WHILE THE MAIN COLD FRONT FROM THIS SYSTEM WILL NOT PUSH THROUGH THE
AREA UNTIL MONDAY NIGHT...WHAT IS LEFT OF THE WEAKENING FRONT NOW
EXTENDING FROM MINNESOTA DOWN INTO TEXAS WILL WORK EAST ACROSS LOWER
MICHIGAN TONIGHT. THIS SHOULD PROVIDE A BETTER FOCUS FOR
SHOWERS/TSTORMS. HIGHER RES RUNS CONTINUE TO SHOW THE CURRENT LINE
OF CONVECTION BREAKING...WITH MOST OF THE ACTIVITY LIFTING TO OUR
WEST AND NORTH...ONLY CLIPPING THE SAGINAW VALLEY. STILL...BETTER
INSTABILITY ARRIVING OVERNIGHT (ELEVATED) WARRANTS CHANCE-LIKELY
POPS AS IT WORKS THROUGH.
LONG TERM...MONDAY THROUGH SATURDAY
DEEP LAYER SOUTHWESTERLY FLOW FIRMLY IN PLACE ON MONDAY WITH THE
REGION STILL LARGELY OUTSIDE THE MAIN HEIGHT FALL CENTER AND
ASSOCIATED UPPER JET CORE ATTENDANT TO THE CLOSED LOW MEANDERING
ACROSS NORTHERN MN. LEAD TROUGH AXIS TRANSLATING THROUGH TONIGHT
WILL SHUNT THE DEEPEST MOISTURE PLUME TO THE EAST BY MONDAY MORNING.
THE OVERALL REDUCTION IN MOISTURE QUALITY AND LACK OF AN APPARENT/
NECESSARY FORCING MECHANISM WITHIN THIS WELL MIXED WARM SECTOR
ENVIRONMENT WILL CONTAIN CONVECTIVE CHANCES PRIOR TO THE COLD
FRONTAL ARRIVAL. ANY EARLY DAY LOW CLOUD DEBRIS WILL MIX OUT...
INCREASING THE LIKELIHOOD FOR SEEING A GOOD BIT OF SUN BY THE MIDDAY
PERIOD. A SOLID LOOKING DIURNAL TEMPERATURE RESPONSE WITH HIGHS
MAKING A RUN INTO THE LOWER AND MIDDLE 80S.
COLD FRONTAL TIMING CENTERING ON THE 21Z-03Z PERIOD MONDAY
EVENING...AN ARRIVAL TIME CERTAINLY FAVORABLE TOWARD CAPITALIZING ON
THE BACK END OF PEAK HEATING. EXISTING ENVIRONMENT LIKELY CARRYING
MLCAPE IN THE BALLPARK OF 1500 J/KG. THIN RIBBON OF HIGHER THETA-E
ANCHORED ON THE BOUNDARY WILL HELP AUGMENT THIS DESTABILIZATION.
THE OVERALL FRONTAL POSITIONING AND TIMING WILL LEAVE A NARROW
WINDOW FOR CONVECTIVE INITIATION TO COMMENCE LOCALLY DURING THE
EVENING...ROUGHLY SOUTHEAST OF A HOWELL TO LAPEER LINE. WHILE THE
STRONGER MID LEVEL WIND FIELD WILL RESIDE BEHIND THE FRONT...SOME
INCREASE IN DEEP LAYER SHEAR WILL OCCUR JUST AS THE FRONT ARRIVES.
MID LEVEL LAPSE RATES REMAIN MODEST...BUT GIVEN THE UNDERLYING LOW
LEVEL THERMODYNAMICS...POTENTIAL WILL EXIST FOR BETTER ORGANIZED
CELLS TO EMERGE WITH AN ACCOMPANYING ISOLATED SEVERE T-STORM RISK.
ENSUING POST-FRONTAL COLD AIR ADVECTION INCREASES HEADING INTO
TUESDAY...WITH 850 MB TEMPERATURES DROPPING A GOOD 15-20 DEGREES IN
24 HOURS. THIS WILL LIKELY TRANSLATE INTO A BROAD STRATOCU FIELD
FOR TUESDAY...WITH TEMPERATURES STRUGGLING TO REACH MUCH ABOVE THE
60 DEGREE MARK. DRY/STABLE PROFILE IN PLACE THROUGH THE MIDWEEK
PERIOD...CONDITIONS DEFINED BY LOW LEVEL ANTICYCLONIC FLOW TUCKED
BENEATH A WEAKLY CONFLUENT WEST-NORTHWEST MID LEVEL PATTERN.
SEASONABLY COOL AIR MASS LEFT TO RESPOND VIA A HIGHER DEGREE OF
INSOLATION ON WEDNESDAY...NO REAL ADVECTIVE COMPONENT IN PLACE.
SLOW MODERATION OF THIS ENVIRONMENT BY THURSDAY/FRIDAY AS UPPER
HEIGHTS START TO REBOUND.
MARINE...
FAVORABLE MARINE CONDITIONS IN TERMS OF WINDS AND WAVES TO FINISH
THE WEEKEND. THE WARM AND INCREASINGLY HUMID CONDITIONS UNDER LIGHT
WIND WILL CONTINUE TO SUPPORT FOG OVER LAKE HURON THROUGH THE
MORNING HOURS. A MARINE DENSE FOG ADVISORY REMAINS IN EFFECT SOUTH
OF SAGINAW BAY. THIS ENVIRONMENT WILL REMAIN FAVORABLE FOR THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. MODEST
SOUTHWESTERLY WINDS DEVELOP IN ADVANCE OF A COLD FRONT ON MONDAY.
COLD FRONT SWEEPS THROUGH MONDAY EVENING WITH COOLER AND DRIER
CONDITIONS DEVELOPING ON WEST TO NORTHWEST FLOW FOR THE MID WEEK
PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...DENSE FOG ADVISORY UNTIL 4 AM EDT MONDAY FOR LHZ421-422-441>443-
462>464.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....BT
UPDATE.......BT
SHORT TERM...HLO
LONG TERM....MR
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1210 PM EDT SUN MAY 17 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 315 AM EDT SUN MAY 17 2015
A WARM FRONT WILL LIFT NORTH TODAY PUTTING SOUTHERN LOWER MICHIGAN
IN AN INCREASINGLY WARM AND HUMID AIRMASS. AN ISOLATED SHOWER OR
STORM IS POSSIBLE TODAY WITH A MUCH BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON AND EVENING. A STRONG COLD
FRONT WILL MOVE THROUGH MONDAY BRINGING A CONTINUED CHANCE FOR A
SHOWER OR THUNDERSTORM. MUCH COOLER WEATHER WILL MOVE IN TUESDAY
THROUGH MIDWEEK.
&&
.UPDATE...
ISSUED AT 1129 AM EDT SUN MAY 17 2015
I CURRENTLY REMAIN UNIMPRESSED ON THE CHANCE OF SEVERE STORMS
LATE THIS AFTERNOON AND THIS EVENING. THE RAP AND NAM FROM THE
LATEST MODEL RUNS HAVE TO CORE OF THE LOW LEVEL JET GOING OVER
NORTHERN LAKE MICHIGAN INTO THE UPPER PENINSULA BETWEEN 4 PM AND
MIDNIGHT. THAT PUTS SOUTHWEST MICHIGAN IN THE SPEED DIVERGENCE
AREA OF THE LOW LEVEL JET (NOT GOOD FOR SEVERE STORMS). THE UPPER
DIVERGENCE FROM THE UPPER LEVEL JET CORE IS OVER THE LOW LEVEL
JET MAX (NORTHERN WISCONSIN) THIS AFTERNOON AND EVENING...NOT
OVER SOUTHWEST MICHIGAN. THE DEEP LAYER SHEAR GREATER THAN 35
KNOTS IS MOSTLY WEST OF US-131 AND NORTH OF MKG THIS AFTERNOON AND
EVENING...REALLY IT IS OVER WISCONSIN (40 TO 60 KNOTS). THE SPC
ENSEMBLE 09Z HAS THE 30 TO 40 PERCENT CHANCE FOR SEVERE STORMS
OVER WISCONSIN THIS AFTERNOON AND EVENING...MEANWHILE A 10 PERCENT
AREA DOES GET INTO WESTERN LOWER MICHIGAN WEST OF US-131 FROM 4 PM
TILL 8 PM. ALL OF THIS TELL ME THE RISK FOR SEVERE STORMS OVER
SOUTHWEST MICHIGAN WOULD BE VERY LOW. STILL IT IS NOT ZERO SO WE
WILL HAVE TO WATCH AS CONDITIONS DEVELOP THIS AFTERNOON AND
EVENING.
OVERALL OUR BEST CHANCE FOR THUNDERSTORMS IS THIS EVENING. I HAVE
NOT SIGNIFICANTLY CHANGED OUR FORECAST IN THAT WAY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 315 AM EDT SUN MAY 17 2015
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
PROBABILITIES FOR CONVECTION TODAY THROUGH MONDAY.
THE AIRMASS OVER OUR FCST AREA WILL BECOME INCREASINGLY WARM AND
HUMID TODAY AS A WARM FRONT GRADUALLY MOVES NORTH OF OUR AREA.
THERE IS JUST A SMALL CHANCE OF AN ISOLATED SHOWER OR THUNDERSTORM
BUT MOST OF OUR AREA WILL STAY DRY THIS MORNING THROUGH MOST OF
THE AFTERNOON.
00Z 4KM WRF-NMM SIM Z GUIDANCE AND THE NSSL WRF SUGGEST THAT
SHOWERS AND THUNDERSTORMS ARE LIKELY TO DEVELOP ACROSS OUR AREA
LATE THIS AFTERNOON THROUGH THE EVENING. CONVECTIVE DEVELOPMENT LATE
THIS AFTERNOON AND EARLY EVENING WILL BE AIDED BY WEAK TO MODERATE
INSTABILITY WITH POTENTIAL FOR SB CAPE VALUES TO REACH AROUND
1000-2000 J/KG.
SHOWERS AND STORMS LATE THIS EVENING WILL BE AIDED BY FORCING
FROM A 35 TO 40 KT LLJ AND STRONG 1000-850 MB MOISTURE TRANSPORT.
A FEW SHOWERS OR ISOLATED STORMS MAY LINGER VERY LATE TONIGHT BUT
THE MOST LIKELY TIME FRAME FOR CONVECTION SEEMS TO BE FROM AROUND
21Z THIS AFTERNOON THROUGH 06Z TONIGHT.
CONVECTIVE POTENTIAL FOR MONDAY IS LARGELY CONTINGENT ON EXACT
COLD FRONTAL TIMING. A CONSENSUS OF LATEST GUIDANCE SUGGESTS THAT
THE BETTER CHANCE FOR STORMS WILL LIKELY STAY SE OF OUR FCST
AREA... BUT THAT SOME SHOWERS AND STORMS MAY REDEVELOP MAINLY OVER
OUR SE FCST AREA PRIOR TO FROPA.
SHORT RANGE GUIDANCE CONTINUES TO SUGGEST SOME WEAK TO MODERATE
INSTABILITY WILL DEVELOP JUST AHEAD OF THE FRONT SO THIS WILL NEED
TO BE MONITORED SINCE FORCING FROM THE FRONT WILL BE STRONG.
HOWEVER IF FRONT MOVES THROUGH FASTER AS SUGGESTED BY THE 00Z GFS
THEN ALL OF OUR FCST AREA SHOULD STAY DRY MONDAY.
IT WILL TURN BREEZY BEHIND THE FRONT MONDAY NIGHT THROUGH TUESDAY
WITH STRONG NW FLOW CAA. MAX TEMPS TUESDAY WILL ONLY REACH THE
50S.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM EDT SUN MAY 17 2015
THREAT OF FROST EXISTS ON TUESDAY NIGHT AS COLD DRY AIR MASS SETTLES
INTO THE REGION FROM THE NORTH. HOWEVER THERE IS STILL SOME QUESTION
AS TO HOW QUICK THE SFC RIDGE BUILDS IN AND WHETHER OR NOT THE WINDS
DIE OFF. EXTENT OF CLEARING IS ALSO UNCERTAIN AT THIS TIME.
OTHERWISE A RATHER QUIET/UNEVENTFUL LONG TERM PERIOD EXPECTED WITH
SURFACE RIDGING AND RELATIVELY COOL DRY AIR MASS DOMINATING OUR
WEATHER. THIS PATTERN SHOULD RESULT IN A DECENT AMOUNT OF SUNSHINE
ALONG WITH LARGE DIURNAL TEMPERATURES SWINGS. EXPECT COOL NIGHTS AND
GENERALLY PLEASANT DAYS WITH LOW HUMIDITIES AND HIGHS MODERATING A
FEW DEGREES EACH DAY.
ONE THING TO WATCH HOWEVER IS THE POTENTIAL FOR CONSIDERABLE MID AND
HIGH CLOUDS AND EVEN SOME SPRINKLES ON WEDNESDAY RELATED TO A SYSTEM
PASSING BY JUST TO OUR SOUTH IN THE ZONAL FLOW. THEN...THE NORTHWEST
FLOW ALOFT ON THURSDAY AND FRIDAY COULD ALSO LEAD TO SOME BRIEF
PERIODS OF THICKER CLOUDS AND SPRINKLES AS WEAK FAST MOVING
SHORTWAVES OCCASIONALLY DROP THROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 757 AM EDT SUN MAY 17 2015
WIDESPREAD MVFR CONDITIONS ARE EXPECTED THROUGH MUCH OF TODAY
WITH LIGHT FOG/HAZE AND CIGS GENERALLY 1500-2500 FT. WHILE
SCATTERED SHOWERS ARE POSSIBLE ALL DAY TODAY...THE MAIN RISK OF
TSTMS SHOULD HOLD OFF UNTIL AFTER 21Z... POSSIBLY EVEN LATER...
LINGERING THROUGH ABOUT 04Z. CIGS LATER TODAY AND THIS EVENING MAY
BECOME PREDOMINATELY VFR...BUT WILL LIKELY TREND BACK DOWN TO MVFR
OR IFR AFTER 04Z TONIGHT. SFC WINDS WILL BE SOUTH AT 10 TO 20 KTS
TODAY AND TONIGHT.
&&
.MARINE...
ISSUED AT 315 AM EDT SUN MAY 17 2015
WE HAVE EXTENDED THE MARINE DENSE FOG ADVISORY THROUGH TONIGHT
SINCE A VERY WARM AND HUMID AIRMASS WILL CONTINUE TO ADVECT IN
OVER RELATIVELY COLD LAKE WATERS AND RESULT IN AREAS OF DENSE FOG.
SOUTHERLY WINDS WILL INCREASE SOMEWHAT THIS AFTERNOON THROUGH
TONIGHT RESULTING IN GRADUALLY INCREASING WAVE HEIGHTS. HOWEVER
WINDS AND WAVE HEIGHTS WILL STAY BELOW SMALL CRAFT CRITERIA
THROUGH TONIGHT. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS LATE
THIS AFTERNOON AND EVENING.
&&
.HYDROLOGY...
ISSUED AT 1210 AM EDT SUN MAY 17 2015
THE MAIN THREAT THROUGH THE NEXT 24 HOURS WILL BE THE POSSIBILITY
FOR LOCALIZED HEAVY RAINFALL.
A MAJORITY OF THE AREA STREAMS AND RIVERS ARE RUNNING WELL BELOW
ADVISORY LEVELS WITH A COUPLE OF SITES SLIGHTLY BELOW. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP AND TRAVEL EAST OUT OF THE
UPPER MIDWEST THIS EVENING AND INTO TONIGHT. AREA AVERAGE
RAINFALL MAY RUN FROM A FEW TENTHS OF AN INCH UPWARDS OF A HALF
INCH. LOCALIZED HEAVY POCKETS WILL CREATE GREAT VARIATIONS IN
RAINFALL TOTALS IN SHORT DISTANCES. LOCATIONS THAT ARE AFFECTED BY
HEAVIER RAINFALL MAY EXPERIENCE LOCALIZED PONDING OR TEMPORARY
STREET FLOODING WITH SMALL CREEK AND STREAM FLUCTUATIONS
POSSIBLE. LARGER RIVERS ARE EXPECTED TO REMAIN BELOW ACTION
STAGE THROUGH THE PERIOD AS FEEDBACK TIMES WILL TAKE US INTO
DRIER WEATHER FOR THE UPCOMING WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...DENSE FOG ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JAM
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
412 PM CDT SUN MAY 17 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM CDT SUN MAY 17 2015
THUNDERSTORMS HAVE BECOME FAIRLY WIDESPREAD THIS AFTERNOON TO THE
EAST OF A COLD FRONT THAT IS ADVANCING EAST ACROSS MN. THE SFC LOW
DRIVING THIS FRONT WAS DOWN TO 995 MB AND SPINNING RATHER
AGGRESSIVELY ACROSS NE SODAK. BASED ON SFC PRESSURE FALLS...THIS LOW
WILL BE ON ITS WAY OFF TO THE ARROWHEAD TONIGHT. WE HAVE QUITE THE
CONTRAST IN AIRMASSES ACROSS THE SYSTEM...WITH SUMMER-LIKE AIR TO
ITS EAST WITH TEMPERATURES IN THE 70S AND DEWPS IN THE 60S...WHILE
WEST OF THE LOW...TEMPERATURES ARE DOWN IN THE MID 30S ACROSS NODAK.
IN FACT...IT IS COLD ENOUGH ON THE WRN EDGE OF THE PRECIP SHIELD
THAT WE ARE SEEING A RAIN/SNOW MIX THIS AFTERNOON.
FOR THE REST OF TODAY...LIKE THE IDEA THAT THE HRRR HAS BEEN RUNNING
WITH ALL DAY THAT MATCHES WELL WITH REALITY NOW. AND THAT IS FOR THE
WIDESPREAD DISCRETE CELLS TO CONTINUE THROUGH THE EVENING AHEAD OF
THE COLD FRONT. WE HAVE SEEN SBCAPE INCREASE TO BETWEEN 1000 AND
1500 J/KG...BUT WITH LITTLE CIN IN PLACE...WE ARE BASICALLY POPPING
CONVECTION AS SOON AS INSTABILITY DEVELOPS. MID-LEVEL LAPSE RATES
ARE PRETTY WEAK THOUGH...WHICH IS A BIG LIMITING FACTOR IN THE SVR.
STILL...FREEZING LEVELS HAVE DROPPED FROM ALMOST 12K FT AGL
YESTERDAY TO BETWEEN 8K AND 9K FEET TODAY...WHICH WILL CONTINUE TO
ALLOW FOR THE THREAT FOR MARGINALLY SVR HAIL THROUGH THE EVENING.
GIVEN THE DEPTH OF THE SYSTEM IN TO OUR NW...WE ARE SEEING LOTS OF
WIND THROUGH PRETTY MUCH THE WHOLE DEPTH OF THE ATMO...SO THESE
SHOWERS WILL LIKELY BE ABLE TO MIX SOME OF THAT DOWN...LEADING TO
SOME GUSTY WINDS AS WELL. TORNADO THREAT DOES NOT LOOK AS GOOD AS
YESTERDAY...WHEN WE HAD A WARM FRONT DRAPED ACROSS THE STATE...BUT
THE RAP HAS BEEN SHOWING 0-1 SHEAR INCREASING LATE THIS AFTERNOON
ACROSS ERN MN/WRN WI...WHERE THE BEST CHANCE FOR SEEING A BRIEF
TORNADO WOULD EXIST.
FOR TONIGHT...THE BIG THING WE WILL SEE IS STRONG CAA AS THE LOW
PUSHES TOWARD THE ARROWHEAD. THIS WILL LEAD TO SOME AGGRESSIVE
TEMPERATURE DROPS OVERNIGHT...WHERE LOWS IN WRN MN WILL FALL BACK
INTO THE MID 30S...OR ABOUT 35 DEGREES COLDER THAN THE HIGHS WERE
THIS AFTERNOON. IN ADDITION TO THE COLD AIR...WE WILL SEE WRAP
AROUND PRECIP DIP DOWN ABOUT AS FAR SOUTH AS A MADISON TO MILLE LACS
LAKE LINE. FORECAST SOUNDINGS IN THIS AREA ARE ALSO COLD ENOUGH TO
SHOW A RAIN/SLEET MIX DEVELOPING LATE TONIGHT. IN FACT...THE NAM
WOULD SAY THE P-TYPE AT AXN WILL BE ALL SLEET TOMORROW MORNING...SO
DID INTRODUCE A PRECIP MIX INTO THE GRIDS. BESIDE THE PRECIP...WINDS
WILL BE STRONG AS WELL. TOP OF THE CHANNEL MIX DOWN AT MOST SITES IN
MN IS OVER 40 KTS. WE ARE RIGHT ON THE CUSP OF NEEDING A WIND
ADVY...BUT DECIDED TO HOLD OFF ON ONE FOR NOW AND WILL LET THE
SEVERE POTENTIAL PLAY OUT BEFORE HOISTING A WIND ADVY.
FOR MONDAY...THERE IS NO WAY AROUND IT...IT WILL BE A RAW DAY. NAM
HAS H85 TEMPS DROPPING TO BETWEEN -5 AND -8C...WHICH IS BELOW THE
CLIMATOLOGICAL RECORD FOR H85 TEMPS FOR THE DAY AT STC/MPX. THROW IN
THE MOSTLY CLOUDY SKIES...AND HAVE HIGH CONFIDENCE IN HIGHS STAYING
IN THE 40S...WITH HIGHS ONLY IN THE 30S OUT TOWARD AXN. THESE VALUES
WILL BE IN THE 25 TO 35 DEGREES BELOW NORMAL RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM CDT SUN MAY 17 2015
THE AFOREMENTIONED STRONG COLD ADVECTION ON MONDAY WILL KEEP THE
LOCAL AREA COOL ON TUESDAY AS WELL WITH HIGHS LIKELY REMAINING IN
THE 50S. THE TROUGH MOVES EAST BY WEDNESDAY AND EAST COAST TROUGH
SHEARS OUT BEFORE ADVANCING OUT OF THE ROCKIES. THEREFORE WE
SHOULD SEE DRY WEATHER AND COOL TO MILD TEMPERATURES THROUGH THE
WEEK...WITH A SLOW WARMING TREND TIME. WE EXPECT TUESDAY AND
WEDNESDAY MORNINGS TO FALL INTO THE 30S ACROSS CENTRAL MN AND WEST
CENTRAL WI...SO WE COULD SEE A LITTLE FROST IF WE MANAGE TO
GET CLEARING AND THE WINDS STAY CALM. WEDNESDAY MORNING HAS A
BETTER CHANCE OF A CALM WIND AND AT LEAST PARTIAL CLEARING. THE
NEXT CHANCE FOR THUNDERSTORMS WILL LIKELY HOLD OFF UNTIL THE
WEEKEND WHEN ANOTHER TROUGH APPROACHES THE REGION FROM THE PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 125 PM CDT SUN MAY 17 2015
LIKE THE IDEA OF THE HRRR...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS DEVELOPING THIS AFTERNOON AS THE STACKED LOW MOVES
THROUGH MN WITH MARGINAL INSTABILITY BUT VIRTUALLY NO CIN. DECIDED
TO CONTINUE TREND OF HANDLING THIS SCENARIO WITH VC GROUPS AND
EXTENDED TEMPO GROUPS FOR THUNDER. HAVE HIGH CONFIDENCE IN STORMS
OCCURRING...JUST LOW CONFIDENCE ON TIMING/TRACKS OF THE NUMEROUS
STORMS THAT ARE EXPECTED. AS WE GET BEHIND THE COLD FRONT...LOW
STRATUS BACK OVER THE DAKOTAS WILL SWING THROUGH...WITH TIMING ON
ITS ARRIVAL NOT TOO DIFFERENT BETWEEN THE HRRR/SREF/NAM/LAMP...SO
MAIN ISSUE WITH THAT IS MORE HOW LOW WILL IT BE AS OPPOSED TO WHEN
WILL THOSE CLOUDS GET TO EACH AIRPORT. MAIN CHANGE MADE TO THE
PREVIOUS TAF WAS TO GO WITH MORE WINDS GIVEN STRENGTH OF MIXED
LAYER WINDS ON NAM SOUNDINGS...WOULD NOT BE SURPRISED TO SEE SOME
WIND GUSTS IN WRN MN TONIGHT THROUGH MON MORNING GET INTO THE 40S
KTS.
KMSP...ALREADY SEEING SHOWERS BUBBLE UP AT 18Z...AND THINKING
THIS THEME OF SCT SHOWERS/STORMS WILL BE WITH US THROUGH ABOUT 1Z.
TEMPO GROUP FOR THUNDER IS BASED ON WHEN THE HRRR BRINGS THE
GREATEST COVERAGE OF STORMS THROUGH. ALSO HAVE HIGH CONFIDENCE IN
MVFR CIGS RETURNING TONIGHT. THOUGH HAVE KEPT CIGS ABOVE 017...MAY
CIGS GET DOWN BETWEEN 010-015 DURING THE MORNING ON MONDAY. WINDS
COULD ALSO BE PROBLEMATIC MONDAY MORNING...WITH STRONG CROSS
WINDS EXPECTED IN THE EARLY MORNING BEFORE WINDS CONTINUE TO VEER
MORE TOWARD A 300 DIRECTION IN THE AFTERNOON.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
THU...VFR. WINDS NNW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
125 PM CDT SUN MAY 17 2015
.UPDATE...
SKIES ARE CLEARING OUT ACROSS THE AREA LATE THIS MORNING AS A
PRONOUNCED MID-LEVEL DRY SLOT TODAY. BIGGEST CHANGE SEEN WITH THE
SEVERE THREAT TODAY IS IT IS NOT LOOKING AS GREAT. THE BIGGEST
REASON IS INSTABILITY LOOKS MARGINAL TODAY...WITH MLCAPES
LARGELY STAYING UNDER 1000 J/KG. THE BIGGEST ISSUE IS WE HAVE
BROAD FORCING WITH THE UPPER WAVE MOVING ACROSS THE REGION WITH AN
UNCAPPED ENVIRONMENT. THE LIMITED CAPPING MEANS AS SOON AS A
LITTLE BIT OF INSTABILITY IS ACHIEVED...CONVECTION WILL BE
INITIATED...WHICH WILL QUICKLY START TO CONSUME ANY CAPE PRESENT.
GIVEN THE LOW LEVEL WIND FIELDS...STRONG WINDS WILL LIKELY BE THE
MAIN THREAT...WITH THE TORNADO THREAT INCREASING SOME THIS
AFTERNOON AS O-1KM INCREASES AHEAD OF THE EWRD ADVANCING COLD
FRONT.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT SUN MAY 17 2015
AN ACTIVE WEATHER DAY IS AHEAD...AS A NEARLY STACKED LOW PRESSURE
SYSTEM PIVOTS ACROSS WESTERN/NORTHERN MINNES0TA.
THE COMPLEX OF SHOWERS AND THUNDERSTORMS THAT BLOSSOMED OVER MO/IA
WILL LIFT NORTH ACROSS SOUTHERN/CENTRAL MN THIS MORNING. BY
18Z...THE BULK OF THE FORECAST AREA SHOULD BE EXPERIENCING A LULL
IN THE ACTIVITY AS SAID CONVECTION LIFTS INTO NORTHERN MN. THE
ASSOCIATED CONVECTIVE DEBRIS /CLOUD COVER/ MAY INITIALLY HINDER
THUNDERSTORM REDEVELOPMENT...BUT AN IMPRESSIVE PUNCH OF PV
ADVECTION WILL LIFT INTO CENTRAL/EASTERN MN BY MID AFTERNOON. MID
LEVEL DRYING IS FORECAST TO WORK INTO SOUTHEAST/EAST CENTRAL MN
THIS AFTERNOON AS WELL...WHICH SHOULD YIELD ADEQUATE SCATTERING
OF THE LOW CLOUDS TO TRIGGER SUFFICIENT ATMOSPHERIC
DESTABILIZATION IN THE WARM SECTOR OVER OUR AREA. SUPERCELL
THUNDERSTORM MODE LOOKS LIKELY...GIVEN THE EXTENT OF DEEP LAYER
SHEAR...AND SFC-3KM PARAMETER VALUES ILLUSTRATE A THREAT FOR
TORNADOES...EVEN THOUGH THE WARM FRONT IS NORTH OF THE AREA. THE
PRIMARY WINDOW FOR SEVERE STORMS LOOKS TO OCCUR BETWEEN 18Z AND
23Z...WITH THE HIGHEST THREAT AREA BEING LOCATIONS ALONG/EAST OF
THE INTERSTATE 35 CORRIDOR. HEAVY RAINFALL WILL BE POSSIBLE AGAIN
TODAY IN THE STRONGER STORMS...ALTHOUGH IT WILL OCCUR PRIMARILY
EAST OF WHERE THE HIGHER TOTALS OCCURRED ON SATURDAY...SO DO NOT
HAVE STRONG FLOODING CONCERNS ABOVE AND BEYOND GENERAL PONDING
ISSUES.
HIGH TEMPS TODAY WILL LIKELY BE THE HIGHEST WE WILL SEE THROUGH
THE NEXT WEEK...WITH HIGHS TOPPING OUT IN THE 70S. LOWS TONIGHT
WILL SNEAK INTO THE UPPER 30S ACROSS WEST CENTRAL MN....WITH 40S
ELSEWHERE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 405 AM CDT SUN MAY 17 2015
THE EXTENDED PERIOD CAN BE CHARACTERIZED AS MAINLY DRY AND
UNSEASONABLY COOL FOR AT LEAST THE FIRST TWO DAYS /MONDAY AND
TUESDAY/...WITH POSSIBLY MORE PRECIPITATION BY NEXT WEEKEND.
MONDAY MORNING THE INTENSE SFC LOW WILL BEGIN TO FILL AND MOVE OFF
TO THE NORTHEAST ACROSS THE NORTHERN GREAT LAKES. WRAP AROUND
MOISTURE WILL BE CONFINED TO CENTRAL/NORTHERN MN WHERE THE HIGHEST
POPS WILL BE LOCATED. HOWEVER...SOME SPRINKLES COULD MOVE INTO
SOUTHERN MN/WC WI DUE TO COLD AIR ALOFT AND RESIDUAL MOISTURE NEAR
THE AREA.
STANDARD 85H/92H TEMPERATURE ANOMALIES ARE 2-4 BLW NORMAL BY
MONDAY/MONDAY NIGHT WHICH TRANSLATES TO SFC TEMPS NEARLY 20-30
DEGREES BELOW NORMAL. EVEN THE GEFS/NAEFS MEAN 85H TEMPS RETURN
INTERVAL BASED ON CLIMATOLOGY /1985 - 2012/ ARE ONCE EVERY 10 YEARS
FOR THESE TYPE OF TEMPS FOR MID MAY. EVEN SOME AREAS IN THE
NORTHERN PLAINS ARE OUTSIDE CLIMATOLOGY NORMS WHICH MEANS SOME
RECORD LOWS ARE POSSIBLE EARLY NEXT WEEK BASED ON THE AMOUNT OF
CLOUD COVER AND SFC WINDS.
THE MEAN UPPER FLOW WILL BE WEST/NW ACROSS THE UPPER MIDWEST
AS AN UPPER RIDGE HOLDS ACROSS WESTERN CANADA...AND AN UPPER LOW
BUILDS SOUTHWARD ACROSS HUDSON BAY BY MIDWEEK. THE MEAN UPPER FLOW
ACROSS THE WESTERN AND SOUTHERN PART OF THE CONUS WILL BE MORE
PROGRESSIVE WITH SEVERAL STORM SYSTEMS AFFECTING THAT REGION. NOT
UNTIL LATE IN THE EXTENDED PERIOD...POSSIBLY AS LATE AS
SATURDAY/SUNDAY WILL WE GET INTO A MORE PROGRESSIVE FLOW FROM
THE SW AS THE UPPER RIDGE BREAKS DOWN IN WESTERN CANADA AND AN UPPER
LOW MOVES INLAND INTO THE SW CONUS. TEMPS WILL SLOWLY MODERATE BY
THE END OF THE WEEK WITH 60S/70S MOVING BACK INTO THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 125 PM CDT SUN MAY 17 2015
LIKE THE IDEA OF THE HRRR...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS DEVELOPING THIS AFTERNOON AS THE STACKED LOW MOVES
THROUGH MN WITH MARGINAL INSTABILITY BUT VIRTUALLY NO CIN. DECIDED
TO CONTINUE TREND OF HANDLING THIS SCENARIO WITH VC GROUPS AND
EXTENDED TEMPO GROUPS FOR THUNDER. HAVE HIGH CONFIDENCE IN STORMS
OCCURRING...JUST LOW CONFIDENCE ON TIMING/TRACKS OF THE NUMEROUS
STORMS THAT ARE EXPECTED. AS WE GET BEHIND THE COLD FRONT...LOW
STRATUS BACK OVER THE DAKOTAS WILL SWING THROUGH...WITH TIMING ON
ITS ARRIVAL NOT TOO DIFFERENT BETWEEN THE HRRR/SREF/NAM/LAMP...SO
MAIN ISSUE WITH THAT IS MORE HOW LOW WILL IT BE AS OPPOSED TO WHEN
WILL THOSE CLOUDS GET TO EACH AIRPORT. MAIN CHANGE MADE TO THE
PREVIOUS TAF WAS TO GO WITH MORE WINDS GIVEN STRENGTH OF MIXED
LAYER WINDS ON NAM SOUNDINGS...WOULD NOT BE SURPRISED TO SEE SOME
WIND GUSTS IN WRN MN TONIGHT THROUGH MON MORNING GET INTO THE 40S
KTS.
KMSP...ALREADY SEEING SHOWERS BUBBLE UP AT 18Z...AND THINKING
THIS THEME OF SCT SHOWERS/STORMS WILL BE WITH US THROUGH ABOUT 1Z.
TEMPO GROUP FOR THUNDER IS BASED ON WHEN THE HRRR BRINGS THE
GREATEST COVERAGE OF STORMS THROUGH. ALSO HAVE HIGH CONFIDENCE IN
MVFR CIGS RETURNING TONIGHT. THOUGH HAVE KEPT CIGS ABOVE 017...MAY
CIGS GET DOWN BETWEEN 010-015 DURING THE MORNING ON MONDAY. WINDS
COULD ALSO BE PROBLEMATIC MONDAY MORNING...WITH STRONG CROSS
WINDS EXPECTED IN THE EARLY MORNING BEFORE WINDS CONTINUE TO VEER
MORE TOWARD A 300 DIRECTION IN THE AFTERNOON.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
THU...VFR. WINDS NNW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...JLT
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
134 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1256 PM CDT SUN MAY 17 2015
MIX OF RAIN AND SNOW IS OCCURRING ACROSS THE NORTH BUT WEB
CAMERAS SHOW LITTLE ACCUMULATIONS SHOWING UP ON GRASSY AREAS AS OF
1 PM CDT. WILL CONTINUE THE WINTER WEATHER ADVISORY START TIME
THIS EVENING. OTHERWISE MODERATE TO SOMETIMES HEAVY RAINFALL
CONTINUES ACROSS EAST CENTRAL NORTH DAKOTA. THE CENTER OF MID
LEVEL CIRCULATION IS SEEN IN THE PRECIPITATION VERY WELL ON RADAR
JUST SOUTH OF ABERDEEN. AS THIS FEATURE MOVE NORTHEAST SHOULD SEE
THE RAIN AREA TRANSLATE SLOWLY EAST FOR THE REMAINDER OF THE
AFTERNOON. CONTINUE THE AREAL FLOOD ADVISORY FROM JAMESTOWN SOUTH
TO THE SOUTH DAKOTA BORDER.
UPDATE ISSUED AT 1052 AM CDT SUN MAY 17 2015
EVOLVING CAPE FORECAST FROM NAM AND HRRR SUGGEST THE THUNDERSTORMS
MAY BECOME MUCH LESS PREVALENT BY THIS AFTERNOON. ADJUSTED TO
SHOWERS. EXPANDED THE WIND ADVISORY WEST TO INCLUDE CENTRAL AND
NORTH CENTRAL NORTH DAKOTA.
UPDATE ISSUED AT 643 AM CDT SUN MAY 17 2015
FORECAST ON TRACK WITH ONLY A COUPLE MINOR ADJUSTMENTS TO POPS
BASED ON CURRENT RADAR TRENDS. WATER VAPOR IMAGERY SHOWS BROAD
CLOSED UPPER LOW FROM EASTERN MONTANA TO EASTERN NEBRASKA WITH
WELL DEFINED CIRCULATION MOVING INTO EASTERN SOUTH DAKOTA. THIS IS
ASSOCIATED WITH A 100KT JET STREAK THAT IS NOSING INTO
SOUTHEASTERN NORTH DAKOTA...SUPPORTING AN EXPANDING AREA OF
SHRA/TSRA. EXPECT THESE TRENDS TO CONTINUE AS UPSTREAM RADARS SHOW
WIDESPREAD SHOWERS AND THUNDERSTORMS CONTINUING TO APPROACH OUR
SOUTHEASTERN AREAS FROM SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SUN MAY 17 2015
CONCERNS THIS FORECAST PERIOD INCLUDE ANOTHER DAY OF HEAVY RAIN FOR
CENTRAL NORTH DAKOTA. STRONG NORTH WINDS AND WIND ADVISORY CRITERIA
EXPECTED FOR EASTERN PARTS OF CENTRAL NORTH DAKOTA. THEN
ATTENTION TURNS TO RAIN CHANGING TO SNOW THIS AFTERNOON AND
TONIGHT...WITH SNOW ACCUMULATIONS EXPECTED AND A WINTER WEATHER
ADVISORY FOR NORTH CENTRAL COUNTIES TONIGHT.
THE UPPER LEVEL LOW WAS OVER EASTERN MONTANA AND WYOMING. IT IS
FORECAST TO MOVE/DEVELOP SOUTHEAST QUICKLY THIS MORNING AS AN
INTENSE UPPER LEVEL SHORTWAVE/IMPULSE MOVES NORTHWARD FROM THE
SOUTHERN PLAINS INTO THE EASTERN DAKOTAS. THIS SHOULD BE THE ONSET
OF HEAVY RAIN OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA TODAY.
IN ADDITION TO THE RAINS THAT FELL ON SATURDAY...ANOTHER INCH OR TWO
OF RAINFALL CAN BE EXPECTED ALONG AND EAST OF A LINE FROM MINOT TO
BISMARCK...WITH 0.25 TO 1 INCH WEST OF THIS LINE.
THIS STRONG UPPER LEVEL LOW WILL BE ASSOCIATED WITH DEEPENING OF THE
SURFACE LOW THAT IS CURRENTLY CENTERED OVER CENTRAL SOUTH DAKOTA.
THIS LOW WILL STRENGTHEN AS IT MOVES NORTHEAST TOWARDS THE ND/SD/MN
BORDER BY THIS EVENING. NORTH WINDS WILL INCREASE TODAY TO 25 TO 35
MPH ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE STRONGEST WINDS OF
30 TO 35 MPH WITH GUSTS TO 45 MPH SHOULD OCCUR FROM BOTTINEAU AND
THE TURTLE MOUNTAINS SOUTHWARD ALONG THE JAMES RIVER VALLEY TO
MCINTOSH AND DICKEY COUNTIES.
THE NORTH WINDS WILL USHER IN MUCH COOLER AIR...AND RAIN WILL MIX
WITH AND CHANGE TO SNOW THIS AFTERNOON NORTHWEST AND NORTH CENTRAL.
THE CHANGEOVER TO SNOW WILL PROGRESS SOUTHEASTWARD TONIGHT AND SNOW
ACCUMULATIONS CAN BE EXPECTED OVER MUCH OF THE FORECAST AREA.
EXPECTING 3 TO 5 INCHES OVER MUCH OF THE NORTH CENTRAL...FROM
STANLEY AND KENMARE IN THE NORTHWEST...TO GARRISON...HARVEY...AND
CARRINGTON IN THE SOUTH...INCLUDING MINOT TO RUGBY AND THE TURTLE
MOUNTAINS. A WINTER WEATHER ADVISORY WILL BE ISSUED FOR THIS AREA.
LESSER AMOUNTS OF SNOW ACCUMULATION ARE EXPECTED TO THE SOUTH AND
WEST.
FREEZING TEMPERATURES IN THE MID 20S TO LOWER 30S WILL BE WIDESPREAD
ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 AM CDT SUN MAY 17 2015
MONDAY MORNING WILL SEE LINGERING RAIN/SNOW SHOWERS AS THE DEEP LOW
PRESSURE SYSTEM REACHES THE GREAT LAKES REGION BY 18Z MON. HIGH
PRESSURE WILL SETTLE OVER THE NORTHERN PLAINS BEHIND THE
LOW...LEADING TO MOSTLY DRY CONDITIONS. IN ADDITION...TEMPERATURES
WILL SHOW A WARMING TREND WITH MAX TEMPS BACK INTO THE 60S BY
MIDWEEK. THE GREATEST WEATHER IMPACT WILL BE FROM FROST/FREEZE
CONDITIONS MONDAY NIGHT AND TUESDAY NIGHT. MONDAY NIGHT IS
EXPECTED TO BE THE COLDER OF THE TWO NIGHTS WITH LOWS REACHING THE
MID 20S.
GFS/ECMWF BRING AN UPPER LOW TO WYOMING BY EARLY
WEDNESDAY...ALTHOUGH PRECIP WITH THIS SYSTEM IS CONFINED TO
LOCATIONS TO OUR SOUTH. THE NEXT CHANCE OF PRECIP WOULD THEN BE NEXT
WEEKEND WITH GFS/ECMWF/ENSEMBLES SHOWING AN UPPER LEVEL TROUGH
ACROSS THE NORTH CENTRAL CONUS WITH SURFACE LOW TRACKING OVER THE
CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1256 PM CDT SUN MAY 17 2015
LARGE STORM CREATING WIDESPREAD IFR CONDITIONS IN LOW CLOUDS...
RAIN...AND FOG. COOLER AIR ACROSS THE NORTH WILL CAUSE SNOW
ACROSS KMOT. CONDITIONS SLOWLY IMPROVING KISN AFTER 06Z.
&&
.HYDROLOGY...
ISSUED AT 415 AM CDT SUN MAY 17 2015
ANOTHER 1 OR 2 INCHES OF RAINFALL IS EXPECTED TODAY ALONG AND EAST
OF A LINE FROM MINOT TO BISMARCK. FLOODING IN LOW LYING AND POOR
DRAINAGE AREAS IS POSSIBLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
MONDAY FOR NDZ003>005-010>013-021>023-025.
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ003>005-011>013-
021>023-025.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM CDT MONDAY FOR
NDZ036-037-046>048-050-051.
WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ MONDAY FOR NDZ019-020-
034-035-042-045.
&&
$$
UPDATE...WAA
SHORT TERM...JV
LONG TERM...JNS
AVIATION...WAA
HYDROLOGY...JV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
131 PM EDT SUN MAY 17 2015
.SYNOPSIS...
A WARM FRONT NORTH OF LAKE ERIE WILL LIFT SLOWLY NORTH TODAY AND
TONIGHT. A COLD FRONT WILL PASS THROUGH THE AREA LATE MONDAY
NIGHT. HIGH PRESSURE WILL BUILD IN TOWARD MID WEEK.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOWERED TEMPS A FEW DEGREES IN THE WEST. LOWERED POPS IN THE EAST
THIS AFTERNOON TO CHANCE POPS. BOTH THE NAM AND THE HRRR SHOWS THIS
WAVE OF SHOWERS MOVING EAST THIS MORNING WITH MORE CONVECTION
DEVELOPING FROM THE WEST.
ORIGINAL DISCUSSION...WARM FRONT JUST TO OUR NORTH WITH SOUTHERLY
FLOW CONTINUING TO BRING MOIST AIR INTO THE AREA OUT OF THE GULF
REGION. SHOWERS ALREADY MOVING THROUGH SOUTHERN AND SOUTHEASTERN
COUNTIES...HELPED BY WEAK SHORT WAVE MOVING THROUGH THE REGION.
EXPECT THIS ACTIVITY TO DRIFT EAST OUT OF THE AREA THROUGH THE
MORNING WITH ADDITIONAL SHOWERS ALONG WITH A FEW THUNDERSTORMS
REDEVELOPING WITH HEATING THIS AFTERNOON. WILL HAVE HIGHEST POPS
SOUTHEAST IN THE LIKELY CATEGORY AND HIGH CHANCE POPS ELSEWHERE.
HIGHS 70S AND LOWER 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
LATE TONIGHT INTO MONDAY THE UPPER RIDGE OVER THE AREA BEGINS TO
SHIFT EAST AND ANOTHER SHORTWAVE IMPULSE BEGINS TO RIDE UP RIDGE
TOWARD THE AREA. HOWEVER...AT THIS POINT IT APPEARS THE BETTER
DYNAMICS WILL STAY SOUTH OF THE AREA. MONDAY AFTERNOON
THUNDERSTORMS WILL INCREASE AHEAD OF A COLD FRONT. RIGHT NOW IT
LOOKS LIKE THE FRONT WON`T ACTUALLY CLEAR CLEVELAND UNTIL
3AM...HOWEVER...THE GREATEST THREAT FOR THUNDERSTORMS WILL OCCUR
OUT AHEAD OF THE FRONT WITH BETTER SURFACE BASED INSTABILITY. THE
UPPER LEVEL PATTERN BECOMES RELATIVELY ZONAL FOR THE REST OF
TUESDAY AND INTO WEDNESDAY AS THINGS DRY OUT AT THE SURFACE AND
HIGH PRESSURE BEGINS TO SETTLE IN.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
MODELS REMAIN IN GOOD AGREEMENT DROPPING LARGE AREA OF CANADIAN HIGH
PRESSURE OVER THE REGION THURSDAY THROUGH EARLY SATURDAY. THE HIGH
WILL MOVE EAST OFF THE MID ATLANTIC COAST LATE SATURDAY INTO SUNDAY.
EXPECTING DRY CONDITIONS ACROSS THE REGION WITH THE HIGH MOVING
ACROSS. SATURDAY NIGHT AND SUNDAY BROUGHT IN CHANCE POPS AS MOISTURE
RETURN IN SOUTHERLY RETURN FLOW ON THE WEST SIDE OF THE HIGH. TEMPS
GENERALLY ON THE COOL SIDE BUT MODERATING THROUGH THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
OCCASIONAL SHOWERS...SOME THUNDER...AND VARIABLE SKY CONDITIONS
WILL CONTINUE INTO MONDAY ACROSS ALL TAF SITES. AN EXITING ROUND
OF SHOWERS WILL MOVE ACROSS NW PA AND KERI EARLY THIS AFTERNOON. A
NEW ROUND OF SHOWERS...SOME OF WHICH COULD DEVELOP FURTHER INTO
TS...NOW POPPING UP FROM KFDY TO KCMH. THIS AREA WILL DRIFT EAST-
NORTHEAST THROUGH THE REMAINDER OF THE AFTERNOON...PEAKING WITH
THE MAX DAYTIME HEATING. MULTI-LEVEL CLOUD DECKS WILL CONTINUE AND
WILL LARGELY BE MVFR TO LOW END VFR. TEMPORARY IFR CONDITIONS
WITHIN ANY SHOWER. WITH THE SUPER MOIST ATMOSPHERE STICKING
AROUND...COULD SEE A SHOWER AT JUST ABOUT ANYTIME TONIGHT. ALSO
WILL LIKELY SEE CONDITIONS DIP BACK DOWN INTO MVFR RANGE WITH VSBY
AND/OR CEILINGS. UNSURE ABOUT THE LIKELIHOOD OF IFR OVERNIGHT. IT
WILL BUBBLE BACK UP AGAIN TOMORROW WITH THE COLD FRONT EXPECTED TO
MOVE ACROSS MONDAY EVENING. THUNDERSTORMS EXPECTED TO BE MORE
ORGANIZED MONDAY...AND SOME COULD BE STRONG. LIGHT SOUTHERLY TO
SSW FLOW WILL CONTINUE OVER THE NEXT 24 HRS. LAKE BREEZE FOR KERI
TODAY REVERSES THIS EVENING. THIS LAKE BREEZE SHOULD NOT REACH
KCLE TODAY.
.OUTLOOK...NON VFR AT TIMES IN SCATTERED SHOWERS OR THUNDERSTORMS
THROUGH MON NIGHT.
&&
.MARINE...
LIGHT SOUTH TO SOUTHWEST FLOW WILL CONTINUE TODAY THROUGH MONDAY
NIGHT. SMALL CRAFT ADVISORY LIKELY NEEDED TUESDAY INTO WEDNESDAY AS
WEST TO SOUTHWEST WINDS INCREASE TO 15 TO 20 KNOTS. A SECOND
REINFORCING SHOT OF COLD AIR WILL COME WITH A SECONDARY COLD FRONT
WILL COME THROUGH LATE TUESDAY...TURNING WINDS MORE NORTHWEST AT
AROUND 20 KNOTS. WEDNESDAY NIGHT WINDS WILL SUBSIDE AS HIGH
PRESSURE BUILDS IN FROM THE WEST.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MAYERS
NEAR TERM...DJB/MAYERS
SHORT TERM...MAYERS
LONG TERM...TK
AVIATION...OUDEMAN
MARINE...TK
AREA FORECAST DISCUSSION
NWS TULSA OK
359 PM CDT SUN MAY 17 2015
.DISCUSSION...
NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS
THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE
RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP
AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER
SHORT TERM HRRR LOOKS GOOD TONIGHT.
NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE
NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST.
CHANCE POPS THURSDAY INTO FRIDAY.
UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS
THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY.
ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND.
GW
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 64 83 60 75 / 10 10 10 10
FSM 68 84 66 81 / 30 30 20 20
MLC 67 84 63 80 / 10 20 20 30
BVO 58 81 54 72 / 10 10 10 10
FYV 62 81 58 76 / 30 30 20 10
BYV 64 81 57 75 / 30 30 20 10
MKO 64 83 61 77 / 10 10 10 30
MIO 63 80 56 73 / 10 10 10 10
F10 64 83 61 77 / 10 10 10 30
HHW 68 83 67 81 / 40 30 20 40
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...14
LONG TERM....21
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
154 PM EDT SUN MAY 17 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST OVER THE REGION EARLY THIS WEEK.
A COLD FRONT WILL APPROACH LATE MONDAY AND MOVE OVER THE AREA ON
TUESDAY...BRINGING INCREASED PRECIPITATION CHANCES TO BOTH THE
MOUNTAINS AND PIEDMONT. SLIGHTLY COOLER AND DRIER HIGH PRESSURE WILL
RETURN ON WEDNESDAY. SOMEWHAT UNSETTLED WEATHER WILL RETURN LATE IN
THE WEEK WITH A STATIONARY FRONT SETTING UP OVER THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 150 PM...WESTERN CAROLINA ZONES WILL GENERALLY REMAIN UNDER A
BKN TO OVC DECK OF MID AND HIGH CLOUDS THROUGH THE REST OF THE
AFTERNOON. LATEST RADAR IMAGES INDICATE A FEW SHRA ACROSS THE
WESTERN NC MTNS AND EXTREME NE GA...MORE CONVECTIVE SHRA OVER THE
NRNMOST NC MTNS. IT APPEARS THAT MARGINAL INSTABILITY AND LATEST
GUIDANCE SUPPORT A CHC LATE AFTERNOON STORMS ACROSS THE MTNS AND
ADJACENT FOOTHILLS. I WILL UPDATE THE FORECAST TO LATEST CONVECTIVE
TIMING...ADJUST SKY TO SAT...AND TEMPS TO OBS.
AS OF 820 AM...REGIONAL RADAR CONTINUES TO INDICATE A FEW PATCHES OF
LIGHT RETURNS ACROSS THE WESTERN CAROLINA AND GEORGIA MTNS. I WILL
ISSUE A QUICK UPDATE TO ADJUST POP...SKY...AND TEMPS TO LATEST
TRENDS.
AS OF 650 AM EDT...EARLY RADAR RETURNS AROUND DAYBREAK ARE WRAPPING
SCATTERED SHOWERS INTO THE FAR SW MTNS. WILL BOOST POPS SLIGHTLY IN
THAT AREA...BUT THE FORECAST TRENDS REMAIN ON TRACK OTHERWISE.
THE HIGHLY AMPLIFIED UPPER FLOW PATTERN OVER THE CONUS WILL KEEP A
RIDGE IN PLACE OVER THE SE THROUGH THE NEAR TERM. PLENTY OF MID AND
HIGH DEBRIS CLOUDS WILL RIDE OVER THE RIDGE AXIS ACROSS THE
AREA...BUT WITH ENOUGH BREAKS TO PERMIT MAX TEMPS TO CLIMB TO ABOUT
5 DEGREES ABOVE CLIMO IN MOST AREAS...AND TO FOSTER A HEALTHY
CUMULUS FIELD. THE NUMERICAL MODELS KEEP THE DEEPEST MOISTURE AND
BEST FORCING FROM S TO SW UPSLOPE FLOW AND LOW LEVEL WIND
CONVERGENCE CONFINED TO THE SPINE OF THE SOUTHERN APPALACHIANS THIS
AFTERNOON AND EVENING. WRN MTN INSTABILITY WILL INCREASE THROUGH THE
DAY...WITH SBCAPE VALUES RUNNING 2000 J/KG OR GREATER BY LATE
AFTERNOON NEAR THE TN BORDER. NAM AND RAP PROFILES HAVE MUCH MORE
LIMITED INSTABILITY EAST OF THE MOUNTAINS...AND THE NAM QPF
PRESENTATION OF MAINLY MTN COVERAGE FOR LATE DAY IS PREFERRED. WILL
THUS FEATURE LIKELY POPS THIS AFTN NEAR THE TN BORDER AND TAPER DOWN
TO BELOW SLIGHT CHANCE FOR CLT METRO.
CONVECTIVE COVERAGE SHOULD WANE QUICKLY THIS EVENING...BUT WILL KEEP
ISOLD SHOWER COVERAGE GOING THROUGH THE NIGHT IN DEVELOPING LIGHT
WESTERLY UPSLOPE FLOW. MILD MINS SHOULD BE ANOTHER 1 TO 2 DEGREES
WARMER THAN THIS MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 200 AM SUNDAY...UPPER HEIGHTS WILL FALL MONDAY OVER THE NERN
CONUS AS LOW PRESSURE MOVES ACRS THE GREAT LAKES. LATEST MODEL PROGS
SHOW LITTLE IMPACT IN THE HEIGHT FIELD OVER THE SOUTHEAST...BUT STILL
SHOW LLVL FLOW VEERING TO NWLY AS THE DAY PROGRESSES. WITHOUT GULF
FLOW ENHANCING WARM/MOIST ADVECTION THE THERMODYNAMIC CONDITIONS WILL
LIKELY BE SIMILAR TO SUNDAY...EXCEPT THAT THE WEAKER RIDGE WILL ALLOW
DEEP CONVECTION OVER THE PIEDMONT AS WELL AS OVER THE MTNS. DEEP
SHEAR REMAINS SMALL. SEVERE DOWNBURST WINDS CANNOT BE TOTALLY RULED
OUT BUT WILL LIKELY REMAIN ISOLATED. PWAT VALUES WELL ABOVE CLIMO AND
SHORT STORM MOTION VECTORS IMPLY HEAVY RAIN WILL BE A MORE LIKELY
THREAT.
AS THE LOW MOVES EWD INTO QUEBEC MON NIGHT...ITS COLD FRONT WILL
CROSS THE SRN APPALACHIANS. EAST OF THE MTNS CONVECTION SHOULD
GRADUALLY WANE WITH THE LOSS OF DIURNAL HEATING...BUT STRENGTHENING
UPSLOPE FLOW MAY ALLOW ACTIVITY TO CONTINUE OVERNIGHT NEAR THE TENN
BORDER. LATER ON TUE THE FRONT WILL PROGRESS ACRS THE CWFA. OVER THE
HIGHER TERRAIN SLIGHTLY COOLER TEMPS AND AN EARLIER THAN NORMAL PEAK
IN CONVECTIVE ACTIVITY ARE EXPECTED. THE PIEDMONT HOWEVER LOOKS TO
SEE A DAY VERY MUCH LIKE MONDAY...PERHAPS EVEN WITH BETTER COVERAGE
DUE TO FRONTAL CONVERGENCE OR MTN LEE TROUGHING. THE THREATS WILL BE
GENERALLY THE SAME.
MAX TEMPS MON/TUE WILL BE AROUND 5 DEG ABOVE CLIMO IN THE MTNS AND
NEAR 10 ABOVE IN THE PIEDMONT. CLOUD COVER WILL HELP KEEP MINS 7-10
DEG ABOVE CLIMO THROUGHOUT THE AREA...BUT TREND COOLER FROM TUE TO
WED MRNG AS THE CANADIAN AIRMASS SETTLES IN.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 130 PM EDT SUNDAY...THE MEDIUM RANGE FCST BEGINS AT 00Z ON
THURSDAY WITH A FLAT UPPER RIDGE OVER THE SE CONUS AND A BROAD UPPER
TROF DIGGING DOWN OVER EXTREME SE CANADA. THIS MOSTLY ZONAL UPPER
PATTERN IS EXPECTED TO PERSIST OVER OUR REGION INTO SAT...AFTER
WHICH...HEIGHTS BEGIN TO RISE AS UPPER RIDGING FROM THE WEST SPREADS
OVER THE REGION AND REMAINS IN PLACE THRU DAY 7.
AT THE SFC...THE REMNANTS OF THE POST FRONTAL CANADIAN HIGH WILL BE
LINGERING OVER THE AREA AT THE START OF THE PERIOD. AS THE PRESSURE
GRADIENT WEAKENS FURTHER...NEAR SFC WINDS WILL BECOME MORE WEAK AND
VARIABLE ON THURS AND REMAIN SO WELL INTO FRI. IN THE
MEANTIME...ANOTHER SFC HIGH WILL WILL MAKE ITS WAY SOUTHWARD FROM
CANADA ON FRI AND SETTLE TO OUR NORTH BY EARLY SAT. THIS SHOULD
CAUSE LOW LVL FLOW TO BECOME MORE NLY AND THEN NELY BY SAT MORNING.
AS WE MOVE INTO SUN...THE CENTER OF THE HIGH BEGINS TO SLIDE OFF THE
EAST COAST AND THE FLOW BECOMES MORE SELY WITH DEEPER MOISTURE
SPREADING BACK OVER THE FCST AREA. AS FOR THE SENSIBLE FCST...BOTH
THURS AND FRI WILL BE CHARACTERIZED BY SLIGHT CHANCE TO LOW END
CHANCE SH AND TS EACH DAY WITH THE BEST CHANCES OVER THE HIGHER
TERRAIN. SAT SHOULD BE MOSTLY DRY WITH HIGH SLIDING BY TO OUR NORTH.
CHANCES FOR MORE WIDESPREAD CONVECTION WILL INCREASE AGAIN ON SUN AS
MORE MOIST...SELY FLOW SPREADS BACK OVER THE REGION. TEMPS WILL
REMAIN ABOVE CLIMO EACH DAY WITH SOME COOLING ON SAT.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT...PATCHES OF MID AND HIGH CLOUDS WILL CONTINUE TO DRIFT OVER
THE TERMINAL THROUGH THE OVERNIGHT HOURS. CU IS EXPECTED TO INCREASE
IN COVERAGE THROUGH THE REST OF THE AFTERNOON...PEAKING WITH SCT
COVERAGE AROUND 050 KFT. HOWEVER...CAPE ACROSS THE REGION IS
EXPECTED TO BE CAPPED AROUND 500 J/KG DUE TO WARM MID LEVEL
TEMPERATURES. LATEST SATELLITE TRENDS AND CAMS INDICATE THAT DEEP
CONVECTION IS NOT FAVORED OVER CLT. THEREFORE...I WILL KEEP
CONDITIONS DRY AND VFR. WINDS SHOULD REMAIN LESS THAN 10 KTS FROM THE
SOUTHWEST THROUGH TONIGHT. AFTER SUNRISE MONDAY...WINDS WILL VEER
FROM FROM SSW AS A LEE TROF FORMS. CU SHOULD DEVELOP BY MID MORNING
WITH BASES AROUND 060 KFT.
ELSEWHERE...WESTERN CAROLINA TERMINALS WILL GENERALLY REMAIN UNDER A
BKN TO OVC DECK OF MID AND HIGH CLOUDS THROUGH THE REST OF THE
AFTERNOON. LATEST RADAR IMAGES INDICATE A FEW SHRA ACROSS THE
WESTERN NC MTNS AND EXTREME NE GA...MORE CONVECTIVE SHRA OVER THE
NRNMOST NC MTNS. IT APPEARS THAT MARGINAL INSTABILITY AND LATEST
GUIDANCE SUPPORT A LATE AFTERNOON TEMPO AT KAVL AND KHKY FOR TSRA.
OTHERWISE...VCSH WILL BE FEATURED IN THE TAFS INTO THIS EVENING.
GUIDANCE AND RECENT MORNING TRENDS INDICATE VFR CONDITIONS OVER DRY
GROUND. BASED ON LOWER VALUES OF CONDENSATION PRESSURE DEFICITS
FROM THE NAM...I WILL INDICATE 4 SM BR BETWEEN 11Z TO 13Z AT KAVL.
AFTER SUNRISE MONDAY...WINDS WILL VEER FROM FROM SSW AS A LEE TROF
FORMS. CU SHOULD DEVELOP BY MID MORNING WITH BASES AROUND 060 KFT.
OUTLOOK...THE REGION WILL REMAIN WITHIN A PLUME OF MOISTURE THROUGH
MID WEEK. MORNING FOG AND STRATUS WILL BE POSSIBLE EACH MORNING
ABOVE WET GROUND. OTHERWISE...EXPECTING LIGHT WINDS WITH AFTERNOON
AND EVENING TSRA. THE MID WEEK PASSAGE OF A COLD FRONT SHOULD
PROVIDE FAIR CONDITIONS LATE IN THE WORK WEEK.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 92% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 97% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 92% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...NED
SHORT TERM...WIMBERLEY
LONG TERM...JPT
AVIATION...NED
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1239 PM CDT SUN MAY 17 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SUN MAY 17 2015
UPPER LOW CENTER CURRENTLY LIFTING NORTH NORTHEAST ACROSS NORTH
CENTRAL NEBRASKA WILL SLOWLY TRACK THROUGH THE FORECAST AREA TODAY.
TWO AREAS OF RAIN SHOWERS WITH EMBEDDED THUNDER ARE IMPACTING THE
AREA. THE FIRST BROAD BAND AHEAD OF THE LOW IS TRACKING NORTHWARD
ACROSS OUR EASTERN COUNTIES AHEAD OF THE SURFACE AND UPPER LOW. THE
SECOND AREA OF PRECIPITATION ON THE BACK SIDE OF THE LOW ACROSS
SOUTH CENTRAL INTO EAST CENTRAL SOUTH DAKOTA IS PIVOTING IN A
GENERAL NORTHERLY DIRECTION IN ASSOCIATION WITH MID LEVEL TROWALING.
PRECIPITATION IS EXPECTED TO PERSIST THROUGH THE MORNING ACROSS
THESE AREAS...WITH DRY SLOTTING LIMITING PRECIPITATION TO MORE
SCATTERED ACTIVITY NEAR THE I29 CORRIDOR. THE HRRR AND RUC HAVE A
DECENT HANDLE IN THE TRACK AND TIMING OF PRECIPITATION...SO FOLLOWED
THESE MODELS. AS THE LOW BEGINS PULLING AWAY TO THE NORTH THIS
AFTERNOON...MUCH OF REGION WILL BE IN THE DRY SLOT...WITH ONLY
SCATTERED SHOWERS DIMINISHING FROM SOUTH TO NORTH THROUGH EARLY
EVENING. SEVERE STORMS ARE NOT EXPECTED WITH ACTIVITY TODAY.
CLOUDY SKIES...RAINFALL... AND COOLER AIR WRAPPING BEHIND THE LOW
WILL KEEP TEMPERATURES IN CHECK THIS AFTERNOON. THE MID TO UPPER 60S
ARE EXPECTED WEST OF I29 WITH THE LOW TO MID 70S TO THE EAST WHERE
THE COOLER AIRMASS WILL BE DELAYED AND A BIT MORE SUNSHINE AND DRIER
WEATHER IS EXPECTED. WINDS WILL INCREASE THROUGH THE DAY AS THE
PRESSURE GRADIENT TIGHTENS AS THE LOW LIFTS NORTH OF THE AREA.
SUSTAINED WINDS WILL BE NEAR ADVISORY LEVEL MID TO LATE
AFTERNOON...BUT RIGHT NOW IT LOOKS LIKE THEY WILL REMAIN TOO LOW FOR
HEADLINES. SKIES WILL REMAIN PARTLY TO MOSTLY CLOUDY TONIGHT WITH
MUCH COLDER TEMPERATURES FILTERING INTO THE REGION. LOWS TONIGHT
WILL BE IN THE MID 30S TO MID 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN MAY 17 2015
WINDY AND COOL STILL LOOKS GOOD FOR MONDAY. THE UPPER LOW WILL BE
FAR ENOUGH NORTHEAST TO PROVIDE LITTLE OR NO DYNAMIC SUPPORT FOR
LIGHT SHOWERS...AND WHILE THERE COULD BE A FEW SPRINKLES WITH THE
LOW CLOUDS...WILL LEAVE OUT FOR NOW. THE LOW CLOUD COVER SHOULD
DOMINATE SKIES OVER THE NORTHEAST TO EAST CENTRAL PART OF THE
FORECAST AREA WITH LESSER CLOUD COVER TO THE SOUTHWEST. TEMPERATURES
WILL BE ON THE VERY CHILLY SIDE WITH HIGHS IN THE MID 40S NORTHEAST
TO THE MID 50S SOUTH.
CLEARING SKIES MONDAY NIGHT WITH HIGH PRESSURE RIDGING INTO THE AREA
AND THIS HIGH WILL ALSO BRING DECREASING WINDS. CHILLY TEMPERATURES
MAY DROP TO FROSTY OR FREEZY LEVELS AND WIND LOOK LIGHT ENOUGH BY
EARLY TUESDAY MORNING TO ALLOW FOR FROST EXCEPT IN PART OF SOUTHWEST
MINNESOTA SO AFTER COORDINATION WILL SO MENTION.
TUESDAY LOOKS FAIRLY SUNNY WITH SOME SLOW INCREASE IN CLOUDS
SOUTHWEST. THIS SLOW CLOUD INCREASE WILL CONTINUE FROM THE SOUTHWEST
TUESDAY NIGHT INTO WEDNESDAY AS AN EJECTED WAVE FROM PACIFIC COAST
TROUGH APPROACHES FROM THE SOUTHWEST. THIS WAVE WILL BE SUPPRESSED
TO SOME DEGREE BY A NORTHWESTERLY UPPER FLOW OVER THE WESTERN GREAT
LAKES. LIGHT RAIN LIKELY SPREADING INTO THE SOUTHWEST CORNER OF THE
AREA LATE TUESDAY NIGHT MAY NOT GET TOO FAR NORTHEAST IF THIS
SUPPRESSION IS STRONG ENOUGH. FOR NOW WILL KEEP SOME MENTION OF
LIGHT RAIN CHANCE WEDNESDAY OVER THE SOUTHWEST HALF OF THE AREA. DO
NOT EXPECT MUCH RAIN IN ANY EVENT AS THE SYSTEM WILL BE STEADILY
WEAKENING WHILE BEING SUPPRESSED BETWEEN THE NORTHWESTERLY FLOW AND A
MODEST SOUTHERN PLAINS RIDGE. TEMPERATURES WILL STILL BE COOL WITH
50S HIGHS TUESDAY AND WEDNESDAY.
THE DEPARTURE OF WHAT IS LEFT OF THE WEAK WAVE WILL ALLOW THE RIDGE
TO BUILD A LITTLE MORE INTO THE AREA AND BRING DRY WEATHER WITH
MODEST WARMING THURSDAY INTO FRIDAY. LATE FRIDAY AND SATURDAY WILL
BRING A CHANCE OF SHOWERS AND STORMS AS THE PACIFIC TROUGH
APPROACHES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1237 PM CDT SUN MAY 17 2015
COMPLEX SET UP THIS AFTERNOON. VFR EAST OF INTERSTATE 29 BUT
SCATTERED THUNDERSTORMS CAN BE EXPECTED THROUGH LATE AFTERNOON.
ALONG AND EAST OF INTERSTATE 29 MVFR CEILINGS...POSSIBLY SHORT
LIVED IFR CEILINGS...ALONG WITH STRATIFORM RAINFALL. THE BULK OF
THIS PRECIPITATION WILL LIFT NORTHEAST WITH ONLY LIGHTER AMOUINTS
EXPECTED ACROSS MOST OF THE CWA. MVFR CEILINGS LIKELY OFF AND ON
THROUGH THE ENTIRE PERIOD. WINDS WILL ALSO BE A PROBLEM WITH
NORTHWEST WINDS GUSTING TO ABOUT 45 MPH AT TIMES...MAINLY BEFORE
6Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM CDT MONDAY FOR
SDZ040-054>056-060>062-065>067.
WIND ADVISORY UNTIL 1 AM CDT MONDAY FOR SDZ038-039-052-053-
057>059-063-064.
MN...WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM CDT MONDAY FOR
MNZ071-072-080-081-089-090-097-098.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...08
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
304 PM CDT SUN MAY 17 2015
.DISCUSSION...
THE MIDSOUTH REMAINS STUCK UNDERNEATH SOUTHWEST FLOW ALOFT. THE
SOUTHWEST FLOW ALOFT HAS BROUGHT THIS WET PATTERN TO THE REGION AS
THE COMBINATION OF SHORTWAVES MOVING THROUGH THE FLOW AND AN
ABUNDANCE OF MOISTURE FROM THE GULF OF MEXICO HAS PRODUCED ROUND
AFTER ROUND OF SHOWERS AND THUNDERSTORMS.
LOOKING AT LATEST RADAR IMAGES...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY HAS NOW PUSHED EAST OF THE MISSISSIPPI
RIVER. MOST OF THIS CONVECTION WILL LIKELY PUSH EAST OF THE CWA BY
7 PM. HOWEVER...LATEST HRRR SHOWS REDEVELOPMENT OCCURRING OVER
NORTHEAST ARKANSAS BY THAT TIME. THE CORRIDOR FROM NORTHEAST
ARKANSAS AND THE MISSOURI BOOTHEEL MAY SEE MOST OF THE CONVECTION
DURING THE LATE EVENING INTO THE OVERNIGHT HOURS BEFORE IT SHIFTS
SOUTHWARD ON MONDAY. HAVE ADJUSTED POPS ACCORDINGLY. IN
ADDITION...SINCE THERE ARE PORTIONS OF NORTHEAST MISSISSIPPI THAT
HAS SEEN SEVERAL ROUNDS OF HEAVY SHOWERS TODAY...WILL GO AHEAD AND
EXPAND THE FLASH FLOOD WATCH SOUTHWARD TO COVER THE ENTIRE CWA
THROUGH MONDAY.
MONDAY WILL BE ANOTHER RAINY DAY FOR THE MIDSOUTH WITH OFF AND ON
PERIODS OF HEAVY SHOWERS AND THUNDERSTORMS. EXPECT HIGHS IN THE
UPPER 70S TO LOWER 80S.
THE COLD FRONT WILL FINALLY BEGIN TO PUSH INTO THE AREA MONDAY
NIGHT INTO TUESDAY. MODELS ARE COMING INTO TO CLOSER AGREEMENT
THAT THE FRONT WILL STALL OUT JUST SOUTH OF THE CWA AND BEGIN
LIFTING BACK NORTHWARD AS A WARM FRONT LATE TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL KEEP SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS IN THE FORECAST FOR PORTIONS OF EAST-CENTRAL
ARKANSAS AND NORTH MISSISSIPPI WHILE GIVING THE REST OF THE CWA
ONL A BRIEF REPRIEVE ON TUESDAY NIGHT.
BY WEDNESDAY...THE ENTIRE MIDSOUTH WILL SEE CHANCES FOR SHOWERS
AND THUNDERSTORMS AGAIN AS A WEAK SHORTWAVE MOVES ACROSS THE CWA.
BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL COME WEDNESDAY
NIGHT INTO THURSDAY AS THE FRONT MOVES BACK THROUGH THE AREA AS A
COLD FRONT.
HIGH PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT THROUGH
SATURDAY. NO PRECIPITATION IS EXPECTED AS A RESULT. HIGHS WILL BE
IN THE MID 70S TO LOWER 80S. LOWS WILL BE IN THE MID 50S TO LOWER
60S.
LOOKS LIKE THE MIDSOUTH COULD BE UNDERNEATH SOUTHWEST FLOW ALOFT
AGAIN BY SATURDAY NIGHT CONTINUING INTO EARLY NEXT WEEK. THIS
COULD BRING ANOTHER EXTENDED WET PERIOD TO THE REGION.
KRM
&&
.AVIATION...
18Z TAFS
MVFR CIGS WILL TO LIFT TO VFR BY 19Z OR SHORTLY THEREAFTER. VFR
CONDS EXPECTED THIS AFTERNOON AND THIS EVENING OUTSIDE OF SHRAS
AND TSRAS. CARRIED VCTS AT ALL TERMINALS THIS AFTERNOON UNTIL
18/00Z WITH LOSS OF HEATING. SHORT RANGE MODELS INDICATE MORE
TSRAS EXPECTED TO FIRE UP ACROSS NE ARKANSAS THIS EVENING SO
PREDOMINANT TSRA FROM 18/02Z-18/06Z LOOKS GOOD. MODELS DISAGREE ON
HOW WIDESPREAD LOW CLOUDS LATER TONIGHT AND MON MORNING. BEST
CHANCES APPEAR TO BE AT KTUP AND PLACED A MVFR CIG THERE MONDAY
MORNING OTRW WILL GO WITH OPTIMISTIC FORECAST. MORE TSRAS
POSSIBLE LATER MON AM INTO THE AFTN.
SOUTH WINDS 10-12 KTS WITH HIGHER GUSTS THIS AFTN...8-10 KTS
TONIGHT.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR DUNKLIN-PEMISCOT.
MS...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR ALCORN-BENTON MS-
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1251 PM CDT SUN MAY 17 2015
.DISCUSSION...UPDATED FOR 18Z AVIATION.
&&
.AVIATION...LOWER CONFIDENCE WIND FORECAST AS A COUPLE OF OUTFLOW
BOUNDARIES ARE PRESENT ACROSS SOUTH TEXAS. SHOWERS AND ISOLATED
THUNDERSTORMS CONTINUE TO IMPACT THE VCT TERMINAL AND WILL PREVAIL
TSRA FOR A SHORT INTERVAL. ANTICIPATE CONVECTION OVER THE NE WILL
PUSH OFF TO THE EAST AND NE. ADDITIONAL SHOWERS AND STORMS WILL BE
POSSIBLE LATER THIS AFTERNOON AND EVENING...MOST LIKELY TO IMPACT
THE ALI AND LRD TERMINALS. MIX OF MVFR/LOW END VFR CONDITIONS THIS
AFTERNOON WILL TRANSITION TO MOSTLY MVFR TONIGHT. SOME POSSIBILITY
OF IFR CIGS TO DEVELOP...BUT NOT CONFIDENT ENOUGH TO INCLUDE IN
THE FORECAST.
&&
.PREV DISCUSSION... /ISSUED 1147 AM CDT SUN MAY 17 2015/
DISCUSSION...EARLIER MCS CONTINUES TO WEAKEN AS EVIDENT WITH
CLOUD TOPS WARMING OVER THE NORTHERN AREAS. LAST OF THE ACTIVITY
FOR NOW REMAINS OVER THE VICTORIA CROSSROADS WHERE SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE ONGOING. CONVECTION SHOULD
PUSH OFF TO THE EAST AND NORTHEAST INTO THE EARLY AFTERNOON. MAIN
REASON FOR THE UPDATE WAS FRESHEN UP THE FORECAST BASED ON LATEST
TRENDS AND EXPIRE SCA AS WINDS HAVE FALLEN BELOW 20 KNOTS .
ATTENTION WILL THEN WILL TURN TO OUT WEST LATER ON THIS EVENING.
LATEST SPC MESOANALYSIS INDICATES INCREASING INSTABILITY BY LATE
THIS AFTERNOON WITH MLCAPES AOA 3500 J/KG. OUTFLOW FROM EARLIER
CONVECTION MAY FOCUS REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
HRRR HAS BEEN HINTING AT THIS FOR THE LAST SEVERAL RUNS WITH
CONVECTION MOVING NORTHWARD OUT OF DEEP SOUTH TEXAS. CONDITIONAL
RISK OF STRONG TO SEVERE THUNDERSTORMS EXISTS IF CONVECTION DOES
INDEED DEVELOP. ALSO...HEAVY RAIN AND LOCALIZED FLOODING WILL BE A
CONCERN WITH SOILS SATURATED FROM RECENT RAINS.
PREV DISCUSSION... /ISSUED 645 AM CDT SUN MAY 17 2015/
DISCUSSION...STORMS HAVE BUILT BACK ALL THE WAY TO EAGLE PASS BUT
THE OVERALL PROGRESSION OF THE LINE CONTINUES TO SHOW EAST-SOUTHEAST
MOVEMENT. CURRENT 12Z SOUNDING AT CRP SHOWS A DRY LAYER BETWEEN
850-700 MB LAYER. LATEST HRRR AND RAP ALONG WITH 06Z NAM STILL
SHOW THAT STORMS SHOULD SHOW WEAKENING TREND AS THEY REACH SOUTH
TEXAS AND ENCOUNTER NEGATIVE THETA-E ADVECTION OVER THE COASTAL
PLAINS. SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...LOW LEVEL FLOW OF 30-35 KNOTS HAS LIMITED FOG
POTENTIAL OVER INLAND AREAS. MVFR CIGS ARE PREVALENT OVER THE
REGION THIS MORNING. MESOSCALE CONVECTIVE SYSTEM MOVING OUT OF
THE HILL COUNTRY IS EXPECTED TO WEAKEN AS IT MOVES TOWARD
SOUTH TEXAS. BUT STORMS SHOULD PERSIST AND REACH THE NORTHERN
COUNTIES BETWEEN 13-15Z. MENTIONED VCTS AT ALI BUT KEPT THE
MENTION OF CONVECTION OUT OF CRP TAFS. OUTFLOW BOUNDARY AND
DEEPER MOISTURE MAY LEAD TO ANOTHER ROUND OF CONVECTION OVER
THE BRUSH COUNTRY THAT COULD AFFECT LRD LATE THIS AFTERNOON
AND EVENING. MVFR CIGS WILL LIFT BY LATE MORNING WITH VFR
CONDITIONS EXPECTED TO BE PREVALENT BY 18Z. MVFR CIGS WILL
MOVE BACK INTO THE COASTAL PLAINS BY 00Z MONDAY AND BE
PREVALENT OVER ALL OF THE REGION BY 06Z.
PREV DISCUSSION... /ISSUED 433 AM CDT SUN MAY 17 2015/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER MORNING WITH A
DILEMMA WITH REGARDS TO AN UPSTREAM MESOSCALE CONVECTIVE SYSTEM.
ENVIRONMENT FOR SUSTAINING MCS NOT AS GOOD AS FRIDAY. GOES SOUNDER
IMAGE OF PRECIPITABLE WATER SHOWS DRIER AIR OVER THE NORTHWEST
GULF OF MEXICO ADVECTING NORTHWARD INTO THE REGION. CORFIDI
VECTORS INDICATE THE MCS SHOULD CONTINUE MOVING TO THE SOUTHEAST
TOWARD THE NORTHERN BRUSH COUNTRY AND VICTORIA CROSSROADS REGION
THIS MORNING. 00Z HI-RES ARW/NMM AND 03Z SREF STRONGLY INDICATED
THIS MCS WOULD REACH NORTHERN COUNTIES WHILE THE 00Z NAM/00Z TECH
WRF ALONG WITH 08Z HRRR/RAP SHOWED THE SYSTEM WOULD WEAKEN
SUBSTANTIALLY AS IT NEARED THE AREA THIS MORNING. MCS STILL LOOKS
WELL ORGANIZED AND WILL LEAN TOWARD BETTER RAIN CHANCES MAINLY FOR
THE NORTHERN COUNTIES THIS MORNING. MOST OF THE SHORT RANGE MODELS
KEPT THE HIGHER LOW LEVEL THETA-E RIDGE AXIS OVER THE BRUSH
COUNTRY FOR THIS AFTERNOON. A DECENT UPPER LEVEL JET STREAK WILL
BE MOVING ACROSS NORTHERN MEXICO NOSING INTO THE BRUSH COUNTRY
THIS AFTERNOON. COULD SEE REDEVELOPMENT OF CONVECTION ALONG LEFT
OVER BOUNDARIES THAT WILL LINGER INTO THE EVENING HOURS. HI-RES
MODELS INDICATED THERE COULD BE SOME ISOLATED POCKETS OF HEAVY
RAIN FORM OVER THE BRUSH COUNTRY LATE THIS AFTERNOON INTO THIS
EVENING. IF SCENARIO BECOMES A BIT CLEARER LATER TODAY...A FLASH
FLOOD WATCH MAY BE NEEDED FOR THE WESTERN COUNTIES. THE LOWER
THETA-E AIR MASS OVER THE NORTHWEST GULF OF MEXICO WILL MOVE
INLAND INTO THE COASTAL BEND ON MONDAY WITH THE HIGHER MOISTURE
REMAINING ALONG THE RIO GRANDE. KEPT CHANCE POPS WEST TO GHOST
10 PERCENT POPS ALONG THE COAST MONDAY.
MARINE...SCA WILL CONTINUE FOR THE EARLY MORNING HOURS. EXPECT
AS CONVECTION MOVES CLOSER TO THE REGION...GRADIENT WILL DECREASE
WITH WIND SPEEDS FALLING BELOW SCA CRITERIA. WAVE WATCH MODEL
INDICATED SWELLS WILL BE INCREASING TODAY TO 5 TO 6 FEET AND
CONTINUE INTO MONDAY WITH PERIODS OF 7 TO 8 SECONDS. WITH THE
CONTINUED MODERATE TO STRONG ONSHORE FLOW AND NEAR NEW MOON...WENT
WITH HIGH RISK OF RIP CURRENTS FOR TODAY THROUGH MONDAY.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...MID/UPPER LEVEL RIDGING
IS PROG TO STRENGTHEN ACROSS THE CWA FOR MID WEEK...THOUGH LATEST
RUNS OF THE ECMWF HAVE BACKED OFF A BIT ON NORTHWARD BUILDING OF
RIDGE. DRIER AIR AT H85 IS ALSO PROG TO BUILD IN FROM THE WESTERN
GULF FOR MID WEEK AND THE COMBINATION OF SAID FEATURES SHOULD RESULT
IN VERY LOW PRECIP CHANCES FOR EASTERN AREAS BOTH WED/THU. BEST
CONVECTIVE CHANCES FOR WESTERN AREAS MID WEEK WILL BE ALONG THE RIO
GRANDE WHERE THE DEEPEST MOISTURE WILL BE LOCATED AND WHERE
CONVECTIVE TEMPS HAVE A BETTER CHANCE OF BEING REACHED. RIDGING
BEGINS TO DAMPEN BY LATE IN THE WEEK AS A STRONG MID/UPPER TROUGH
SWINGS INTO THE PLAINS RESULTING IN A RETURN TO A POTENTIAL WET
WEATHER PATTERN FOR SOUTH TEXAS BY LATE IN THE EXTENDED PERIOD AS A
SURFACE FRONT TRIES TO WORK SOUTH INTO CENTRAL TEXAS. TEMPERATURES
THROUGH THE WEEK ARE PROG TO BECOME INCREASINGLY MORE SUMMERLIKE
WITH HIGHS IN THE 90S...LOWS IN THE 70S...ALONG WIT HUMID CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 77 87 77 88 76 / 20 10 10 10 10
VICTORIA 76 87 75 89 74 / 20 20 10 10 10
LAREDO 76 94 76 95 76 / 40 20 20 10 10
ALICE 76 90 75 93 74 / 20 20 10 10 10
ROCKPORT 78 86 78 86 78 / 20 10 10 10 10
COTULLA 74 90 75 92 74 / 40 40 20 10 10
KINGSVILLE 77 89 76 90 76 / 20 10 10 10 10
NAVY CORPUS 78 86 77 86 77 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK THROUGH MONDAY EVENING FOR THE FOLLOWING
ZONES: ARANSAS...CALHOUN...KLEBERG...NUECES.
GM...NONE.
&&
$$
TB/78...AVIATION
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1147 AM CDT SUN MAY 17 2015
.DISCUSSION...EARLIER MCS CONTINUES TO WEAKEN AS EVIDENT WITH
CLOUD TOPS WARMING OVER THE NORTHERN AREAS. LAST OF THE ACTIVITY
FOR NOW REMAINS OVER THE VICTORIA CROSSROADS WHERE SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE ONGOING. CONVECTION SHOULD
PUSH OFF TO THE EAST AND NORTHEAST INTO THE EARLY AFTERNOON. MAIN
REASON FOR THE UPDATE WAS FRESHEN UP THE FORECAST BASED ON LATEST
TRENDS AND EXPIRE SCA AS WINDS HAVE FALLEN BELOW 20 KNOTS .
ATTENTION WILL THEN WILL TURN TO OUT WEST LATER ON THIS EVENING.
LATEST SPC MESOANALYSIS INDICATES INCREASING INSTABILITY BY LATE
THIS AFTERNOON WITH MLCAPES AOA 3500 J/KG. OUTFLOW FROM EARLIER
CONVECTION MAY FOCUS REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS.
HRRR HAS BEEN HINTING AT THIS FOR THE LAST SEVERAL RUNS WITH
CONVECTION MOVING NORTHWARD OUT OF DEEP SOUTH TEXAS. CONDITIONAL
RISK OF STRONG TO SEVERE THUNDERSTORMS EXISTS IF CONVECTION DOES
INDEED DEVELOP. ALSO...HEAVY RAIN AND LOCALIZED FLOODING WILL BE A
CONCERN WITH SOILS SATURATED FROM RECENT RAINS.
&&
.PREV DISCUSSION... /ISSUED 645 AM CDT SUN MAY 17 2015/
DISCUSSION...STORMS HAVE BUILT BACK ALL THE WAY TO EAGLE PASS BUT
THE OVERALL PROGRESSION OF THE LINE CONTINUES TO SHOW EAST-SOUTHEAST
MOVEMENT. CURRENT 12Z SOUNDING AT CRP SHOWS A DRY LAYER BETWEEN
850-700 MB LAYER. LATEST HRRR AND RAP ALONG WITH 06Z NAM STILL
SHOW THAT STORMS SHOULD SHOW WEAKENING TREND AS THEY REACH SOUTH
TEXAS AND ENCOUNTER NEGATIVE THETA-E ADVECTION OVER THE COASTAL
PLAINS. SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...LOW LEVEL FLOW OF 30-35 KNOTS HAS LIMITED FOG
POTENTIAL OVER INLAND AREAS. MVFR CIGS ARE PREVALENT OVER THE
REGION THIS MORNING. MESOSCALE CONVECTIVE SYSTEM MOVING OUT OF
THE HILL COUNTRY IS EXPECTED TO WEAKEN AS IT MOVES TOWARD
SOUTH TEXAS. BUT STORMS SHOULD PERSIST AND REACH THE NORTHERN
COUNTIES BETWEEN 13-15Z. MENTIONED VCTS AT ALI BUT KEPT THE
MENTION OF CONVECTION OUT OF CRP TAFS. OUTFLOW BOUNDARY AND
DEEPER MOISTURE MAY LEAD TO ANOTHER ROUND OF CONVECTION OVER
THE BRUSH COUNTRY THAT COULD AFFECT LRD LATE THIS AFTERNOON
AND EVENING. MVFR CIGS WILL LIFT BY LATE MORNING WITH VFR
CONDITIONS EXPECTED TO BE PREVALENT BY 18Z. MVFR CIGS WILL
MOVE BACK INTO THE COASTAL PLAINS BY 00Z MONDAY AND BE
PREVALENT OVER ALL OF THE REGION BY 06Z.
PREV DISCUSSION... /ISSUED 433 AM CDT SUN MAY 17 2015/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER MORNING WITH A
DILEMMA WITH REGARDS TO AN UPSTREAM MESOSCALE CONVECTIVE SYSTEM.
ENVIRONMENT FOR SUSTAINING MCS NOT AS GOOD AS FRIDAY. GOES SOUNDER
IMAGE OF PRECIPITABLE WATER SHOWS DRIER AIR OVER THE NORTHWEST
GULF OF MEXICO ADVECTING NORTHWARD INTO THE REGION. CORFIDI
VECTORS INDICATE THE MCS SHOULD CONTINUE MOVING TO THE SOUTHEAST
TOWARD THE NORTHERN BRUSH COUNTRY AND VICTORIA CROSSROADS REGION
THIS MORNING. 00Z HI-RES ARW/NMM AND 03Z SREF STRONGLY INDICATED
THIS MCS WOULD REACH NORTHERN COUNTIES WHILE THE 00Z NAM/00Z TECH
WRF ALONG WITH 08Z HRRR/RAP SHOWED THE SYSTEM WOULD WEAKEN
SUBSTANTIALLY AS IT NEARED THE AREA THIS MORNING. MCS STILL LOOKS
WELL ORGANIZED AND WILL LEAN TOWARD BETTER RAIN CHANCES MAINLY FOR
THE NORTHERN COUNTIES THIS MORNING. MOST OF THE SHORT RANGE MODELS
KEPT THE HIGHER LOW LEVEL THETA-E RIDGE AXIS OVER THE BRUSH
COUNTRY FOR THIS AFTERNOON. A DECENT UPPER LEVEL JET STREAK WILL
BE MOVING ACROSS NORTHERN MEXICO NOSING INTO THE BRUSH COUNTRY
THIS AFTERNOON. COULD SEE REDEVELOPMENT OF CONVECTION ALONG LEFT
OVER BOUNDARIES THAT WILL LINGER INTO THE EVENING HOURS. HI-RES
MODELS INDICATED THERE COULD BE SOME ISOLATED POCKETS OF HEAVY
RAIN FORM OVER THE BRUSH COUNTRY LATE THIS AFTERNOON INTO THIS
EVENING. IF SCENARIO BECOMES A BIT CLEARER LATER TODAY...A FLASH
FLOOD WATCH MAY BE NEEDED FOR THE WESTERN COUNTIES. THE LOWER
THETA-E AIR MASS OVER THE NORTHWEST GULF OF MEXICO WILL MOVE
INLAND INTO THE COASTAL BEND ON MONDAY WITH THE HIGHER MOISTURE
REMAINING ALONG THE RIO GRANDE. KEPT CHANCE POPS WEST TO GHOST
10 PERCENT POPS ALONG THE COAST MONDAY.
MARINE...SCA WILL CONTINUE FOR THE EARLY MORNING HOURS. EXPECT
AS CONVECTION MOVES CLOSER TO THE REGION...GRADIENT WILL DECREASE
WITH WIND SPEEDS FALLING BELOW SCA CRITERIA. WAVE WATCH MODEL
INDICATED SWELLS WILL BE INCREASING TODAY TO 5 TO 6 FEET AND
CONTINUE INTO MONDAY WITH PERIODS OF 7 TO 8 SECONDS. WITH THE
CONTINUED MODERATE TO STRONG ONSHORE FLOW AND NEAR NEW MOON...WENT
WITH HIGH RISK OF RIP CURRENTS FOR TODAY THROUGH MONDAY.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...MID/UPPER LEVEL RIDGING
IS PROG TO STRENGTHEN ACROSS THE CWA FOR MID WEEK...THOUGH LATEST
RUNS OF THE ECMWF HAVE BACKED OFF A BIT ON NORTHWARD BUILDING OF
RIDGE. DRIER AIR AT H85 IS ALSO PROG TO BUILD IN FROM THE WESTERN
GULF FOR MID WEEK AND THE COMBINATION OF SAID FEATURES SHOULD RESULT
IN VERY LOW PRECIP CHANCES FOR EASTERN AREAS BOTH WED/THU. BEST
CONVECTIVE CHANCES FOR WESTERN AREAS MID WEEK WILL BE ALONG THE RIO
GRANDE WHERE THE DEEPEST MOISTURE WILL BE LOCATED AND WHERE
CONVECTIVE TEMPS HAVE A BETTER CHANCE OF BEING REACHED. RIDGING
BEGINS TO DAMPEN BY LATE IN THE WEEK AS A STRONG MID/UPPER TROUGH
SWINGS INTO THE PLAINS RESULTING IN A RETURN TO A POTENTIAL WET
WEATHER PATTERN FOR SOUTH TEXAS BY LATE IN THE EXTENDED PERIOD AS A
SURFACE FRONT TRIES TO WORK SOUTH INTO CENTRAL TEXAS. TEMPERATURES
THROUGH THE WEEK ARE PROG TO BECOME INCREASINGLY MORE SUMMERLIKE
WITH HIGHS IN THE 90S...LOWS IN THE 70S...ALONG WIT HUMID CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 87 77 87 77 88 / 20 20 10 10 10
VICTORIA 87 76 87 75 89 / 50 20 20 10 10
LAREDO 94 76 94 76 95 / 30 40 20 20 10
ALICE 91 76 90 75 93 / 30 20 20 10 10
ROCKPORT 86 78 86 78 86 / 20 20 10 10 10
COTULLA 89 74 90 75 92 / 40 40 40 20 10
KINGSVILLE 89 77 89 76 90 / 30 20 10 10 10
NAVY CORPUS 86 78 86 77 86 / 20 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK THROUGH MONDAY EVENING FOR THE FOLLOWING
ZONES: ARANSAS...CALHOUN...KLEBERG...NUECES.
GM...NONE.
&&
$$
TB/78...SHORT TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT SUN MAY 17 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 303 PM CDT SUN MAY 17 2015
MAIN CONCERN IS SEVERE THREAT LATE THIS AFTERNOON INTO THIS
EVENING.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS UPPER LEVEL LOW/TROUGH
OVER EASTERN SOUTH DAKOTA AND WESTERN MINNESOTA...IN ADDITION A
SHORTWAVE TROUGH OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA.
LATEST 19Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTHEAST
NORTH DAKOTA AND WEST CENTRAL MINNESOTA...WITH A COLD FRONT
EXTENDING SOUTH INTO WESTERN IOWA. LATEST SATELLITE IMAGERY SHOWS
STRATUS OVER FORECAST AREA BECOMING MORE CELLUAR AND SCATTERED
SHOWERS DEVELOPED OVER NORTH CENTRAL WISCONSIN AND PARTS OF
SOUTHEAST MINNESOTA PER LATEST ARX RADAR.
WITH THE STRATUS DECK OVER MUCH OF THE REGION THROUGH EARLY
AFTERNOON HOURS...THIS HAS LIMITED INSTABILITY OVER FORECAST AREA
THIS AFTERNOON...WITH THE 17.19Z LAPS SHOWING 200-800 J/KG OVER
FORECAST AREA AND AROUND 1000-1200 J/KG ALONG AND JUST AHEAD OF
THE COLD FRONT. THE LATEST SPC MESOSCALE ANALYSIS INDICATES 40
KNOTS OF 0-6KM SHEAR OVER FORECAST AREA...WITH THE BEST SHEAR IN
THE 0-3KM SHEAR PER 17.18Z RAP OF 30 TO 40 KNOTS ALONG AND AHEAD
OF SURFACE FRONT. SPC MESOSCALE 0-1KM SHEAR INDICATES ABOUT 10 TO
20 KNOTS ALONG AND AHEAD OF COLD FRONT. WITH MINIMAL INSTABILITY
AND SHEAR DECREASING OVER FORECAST AREA...SEVERE THREAT OVER
FORECAST AREA HAS DECREASED. HOWEVER CANNOT RULE OUT AN ISOLATED
SEVERE THUNDERSTORM WITH DAMAGING WINDS...LARGE HAIL OR POSSIBLY
AN ISOLATED TORNADO LATE THIS AFTERNOON INTO THIS EVENING.
MONDAY...FORECAST AREA REMAINS UNDER THE INFLUENCE OF THE UPPER
LEVEL LOW/TROUGH OVER SOUTHERN ONTARIO AND LAKE SUPERIOR. THE
17.12Z GFS/NAM INDICATE COLD AIR ADVECTING INTO THE FORECAST
AREA...WITH 925MB TEMPERATURES FALLING TO 0 TO MINUS 2 DEGREES
CELSIUS OVER THE FORECAST AREA. HIGH TEMPERATURES ARE EXPECTED TO
BE WELL BELOW NORMAL...WITH READINGS IN THE UPPER 40S TO LOWER 60S
ACROSS THE FORECAST AREA. TIGHT PRESSURE GRADIENT WILL ALLOW FOR
WINDS TO BE SUSTAINED AT 15 TO 20 KNOTS AND GUSTS OF 20 TO 30
KNOTS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN MAY 17 2015
TUESDAY INTO WEDNESDAY...SURFACE RIDGE BUILDS INTO MUCH OF MINNESOTA
AND NORTHERN WISCONSIN. SUBSIDENCE UNDERNEATH THE RIDGE SHOULD ALLOW
FOR DRY WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES TUESDAY AND
TUESDAY NIGHT. PATCHY TO AREAS OF FROST IS POSSIBLE ACROSS PARTS OF
CENTRAL WISCONSIN TUESDAY NIGHT INTO WEDNESDAY MORNING. MID TO HIGH
CLOUDS STREAMING AHEAD OF SHORTWAVE TROUGH SOUTHWEST OF FORECAST
AREA MAY NOT ALLOW TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE
30S. TIMING OF MOISTURE ABOVE 700MB WILL BE THE BIGGEST FACTOR AND
THIS IS EVIDENT BY THE 17.12Z GFS/NAM.
WEDNESDAY...SHORTWAVE TROUGH FLATTENS UPPER LEVEL SHORTWAVE RIDGE
WEDNESDAY OVER NEBRASKA AND IOWA. WITH DRY AIRMASS IN PLACE OVER
FORECAST AREA AND THE DEEPER FORCING/LIFT ASSOCIATED WITH SHORTWAVE
TROUGH SOUTH OF FORECAST AREA...HIGHER PRECIPITATION/SHOWER
CHANCES WILL REMAIN MAINLY SOUTH OF FORECAST AREA WEDNESDAY.
HOWEVER...THE 17.12Z GFS/NAM SUGGEST 500-300MB PV ADVECTION ALONG
THE MINNESOTA AND IOWA BORDER DURING THE DAY WEDNESDAY. WILL
INTRODUCE A SMALL PRECIPITATION CHANCE OVER THE EXTREME SOUTH PART
OF THE FORECAST AREA...AS THE 17.12 GFS/NAM DEVELOP LIGHT QPF...A
HUNDREDTH OR TWO...OVER THE EXTREME SOUTHERN PART OF THE FORECAST
AREA.
MAIN FORECAST CONCERNS FROM WEDNESDAY NIGHT INTO MEMORIAL DAY
WEEKEND ARE PRECIPITATION CHANCES FOR MEMORIAL DAY WEEKEND. THE
17.12Z GFS/ECMWF/GEM ARE IN GOOD AGREEMENT IN BUILDING IN
SHORTWAVE/SURFACE RIDGE INTO THE UPPER MIDWEST AND GREAT LAKES
REGION WEDNESDAY NIGHT INTO FRIDAY PROVIDING DRY WEATHER AND
SLIGHTLY TO NEAR NORMAL TEMPERATURES BOTH DAYS. FOCUS TURNS TO
MEMORIAL DAY WEEKEND...WHERE THE 17.12Z GFS/ECMWF ARE IN GOOD
AGREEMENT IN EJECTING PIECES OF ENERGY OUT OF UPPER LEVEL LOW/TROUGH
OVER THE SOUTHWEST UNITED STATES INTO THE CENTRAL UNITED STATES.
BOTH THE 17.12Z GFS/ECMWF SHOW INCREASING LOW LEVEL JET/MOISTURE
TRANSPORT/CONVERGENCE AND LIFT/FORCING SATURDAY INTO SUNDAY INTO THE
FORECAST AREA. WILL CONTINUE TO TREND OF SHOWERS AND THUNDERSTORMS
SATURDAY INTO SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 600 PM CDT SUN MAY 17 2015
SCATTERED SHRA/TS WILL CONTINUE TO PUSH NORTH/NORTHEAST THIS
EVENING...LIKELY WORKING NORTH OF KRST/KLSE BY 01Z OR SHORTLY
AFTERNOON. BRIEF MVFR CONDITIONS WITH ANY STORM.
EXPECTING SOME CLEARING AND MOSTLY SCT VFR CONDITIONS INTO THE
OVERNIGHT. AS THE RESPONSIBLE STORM SYSTEM MOVES INTO SOUTHERN
CANADA...CLOUD SHIELD WEST OF THE LOW LOOKS TO SINK ACROSS THE TAF
SITES AFTER 12Z MONDAY. MVFR CIGS LOOK LIKELY FOR KRST FOR MUCH OF
THE DAY...AND PERHAPS FOR A FEW HOURS AT KLSE.
TIGHT PRESSURE GRADIENT WILL KEEP WINDS STRONG AND GUSTY TONIGHT
THROUGH MONDAY. SUSTAINED NEAR 20 KTS FOR KRST. LOOK FOR A SHIFT TO
WEST WINDS OVERNIGHT AS A COLD FRONT SLIDES WEST-EAST ACROSS THE
AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
552 PM CDT SUN MAY 17 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED
LOW PRESSURE SYSTEM SPINNING OVER THE EASTERN DAKOTAS. SHORTWAVES
ARE ROTATING NORTHWARD AHEAD OF THIS OCCLUDED CYCLONE...THE
STRONGEST OF WHICH IS LOCATED OVER EASTERN IOWA. A PWAT AXIS IS
MOVING ACROSS WISCONSIN EARLY THIS AFTERNOON...WHICH COMBINED WITH
MOISTURE CONVERGENCE...IS CONTRIBUTING TO SCATTERED SHOWER
DEVELOPMENT OVER CENTRAL WISCONSIN. CLOUD COVER HAS SIGNIFICANTLY
SLOWED THE HEATING CURVE SO FAR TODAY...KEEPING ML CAPES BELOW 200
J/KG. WITH SHOWER COVERAGE EXPECT TO INCREASE THROUGH THE
AFTERNOON...IT WILL BE TOUGH TO SEE MUCH OF AN INCREASE OF
INSTABILITY. STILL THOUGH...RADAR ECHOES SUGGEST SOME THUNDERSTORMS
WILL BE POSSIBLE...AND ANY STORMS COULD BRING DOWN STRONG WINDS FROM
ALOFT. WILL HAVE TO KEEP A MENTION OF ISOLATED DAMAGING WINDS
THROUGH EARLY THIS EVENING. OTHERWISE...THE LATEST HRRR CONGEALS THE
SHOWER ACTIVITY INTO BAND AND PROGRESSES IT ACROSS THE FORECAST AREA
FOR THE REST OF THE AFTERNOON.
TONIGHT...LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN
MINNESOTA...WHILE A COLD FRONT WILL PUSH EAST THROUGH ALL BUT FAR
EASTERN WISCONSIN OVERNIGHT. THOUGH SHORTWAVE ENERGY WILL BE
ROTATING NORTHEAST OVER NORTHWEST WISCONSIN THROUGH THE
EVENING...CONCERNED THAT STRONG DRYING AND INCREASING CAPPING IN THE
MID-LEVELS WILL EVEN FURTHER LIMIT THUNDERSTORM POTENTIAL FOR THE
FIRST COUPLE HOURS IN THE EVENING. WILL KEEP A MENTION OF ISOLATED
DAMAGING WINDS THROUGH 02Z IN CASE SOME THUNDERSTORMS MAKE A RUN
INTO N-C WISCONSIN FROM MINNESOTA. ONCE THE THREAT OF STORMS ENDS...MODELS
SHOW CLEARING TAKING PLACE UNTIL LOW CLOUDS FLOOD EAST BEHIND THE
COLD FRONT LATE TONIGHT. LOW TEMPS NEAR 60 OVER THE EAST...BUT
COOLING TO NEAR 50 OVER THE WEST.
MONDAY...OCCLUDED LOW PRESSURE WILL BE WEAKENING AS IT MOVES TO THE
EAST ACROSS LAKE SUPERIOR. WEST WINDS ON THE SOUTHERN FLANK OF THE
LOW WILL BE COLD ADVECTING THROUGH THE DAY...WHILE PUSHING IN WRAP
AROUND MOISTURE. SHOULD SEE AMPLE CLOUD COVER OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THROUGH THE DAY...BUT EAST-CENTRAL WISCONSIN
WILL LIKELY SEE SOME SUN IN THE MORNING BEFORE CLOUDS INCREASE IN
THE AFTERNOON. WITH THE SUNSHINE...TEMPS SHOULD WARM TO NEAR 70 IN
THE EAST...BUT ONLY INTO THE MID AND UPPER 50S OVER THE WEST.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK...DRY
AND MILDER CONDITIONS FOR THE LATTER HALF...AND A POSSIBLE RETURN
TO WET WEATHER LATER IN THE MEMORIAL DAY WEEKEND...ARE THE MAIN
FCST CONCERNS.
THE REMNANTS OF THE UPPER LOW WILL TRACK ACROSS NORTHERN LAKE SUPERIOR
ON MONDAY NIGHT...FOLLOWED BY A S/W TROF PASSING NORTH OF WI ON TUESDAY.
UNSEASONABLY COLD AIR (H8 TEMPS -8 TO -10 C) WILL FLOW INTO THE REGION
ON NNW WINDS...SETTING THE STAGE FOR SOME LAKE-ENHANCED SHOWERS OVER
NC WI. LOW-LEVEL TEMPS AND THICKNESSES SUPPORT A MIX THEN CHANGEOVER
TO SNOW LATE MONDAY NIGHT INTO TUESDAY MORNING...WITH LITTLE OR NO
ACCUMULATION EXPECTED. ANY LINGERING PCPN SHOULD END TUESDAY AFTERNOON
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION.
HIGH PRESSURE WILL COVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. STILL
EXPECTING FROST TUESDAY NIGHT...BUT GETTING A LITTLE CONCERNED ABOUT
THE POSSIBILITY OF THICKER HIGH LEVEL CLOUDS...DUE TO THE PRESENCE
OF A STRONG JET STREAK OVER THE REGION. RIGHT NOW...HAVE JUST
BUMPED UP CLOUD COVER A BIT OVER C/EC WI...BUT KEPT MOSTLY CLEAR
SKIES OVER NORTHERN WI. WILL CONTINUE TO CARRY WIDESPREAD FROST OR
FREEZE CONDITIONS OVER NORTHERN WI...AND PATCHY FROST OVER MOST OF
C/EC WI.
A WEAK BACK DOOR COLD FRONT WILL SAG THROUGH THE FORECAST AREA THURSDAY
INTO THURSDAY NIGHT...BUT WILL NOT HAVE ANY MOISTURE TO WORK WITH...SO
DRY WEATHER WILL PREVAIL. BEHIND THE FRONT...CANADIAN HIGH PRESSURE
WILL REESTABLISH ITSELF OVER THE WESTERN GREAT LAKES...AND IS EXPECTED
TO LINGER INTO SATURDAY. ABUNDANT SUNSHINE SHOULD BRING A RETURN TO
NEAR NORMAL TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
AN UPPER TROF...LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
IMPACT THE REGION FROM SATURDAY NIGHT INTO SUNDAY. GULF MOISTURE
IS EXPECTED TO FLOW INTO THE REGION AHEAD OF THE FRONT...WITH
PRECIPITABLE WATER VALUES REACHING 1.00-1.25 INCHES. HAVE RAMPED
POPS UP TO LIKELY FOR SUNDAY. THE ECMWF PULLS MOST OF THE PCPN OUT
OF THE REGION SUNDAY EVG...WHILE THE GFS HANGS ONTO SIGNIFICANT
QPF INTO MEMORIAL DAY...SO FCST CONFIDENCE WANES BEYOND SUNDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 552 PM CDT SUN MAY 17 2015
MARGINAL TO STRONG SHEAR ALONG WITH MARGINAL INSTABILITY WILL
CONTINUE TO PRODUCE AN ENVIRONMENT FOR THE DEVELOPMENT OF STORMS
THIS SUNDAY EVENING. PRIMARY FOCUS OF STRONGER STORMS THIS
EVENING APPEAR TO BE OVER THE NORTHWEST HALF THE STATE INCLUDING
PARTS OF CENTRAL AND NORTH CENTRAL WISCONSIN. IFR CONDITIONS WITH
LIFR CIGS WILL LINGER ALONG THE LAKE MICHIGAN SHORE LINE.
SOUTHWEST WINDS WILL IMPROVE CONDITIONS OVERNIGHT. OTHERWISE AFTER
A PERIOD OF VFR CONDITIONS OVERNIGHT...MVFR CIGS WILL FILTER INTO
THE STATE FROM NORTHWEST TO SOUTHEAST THROUGH MONDAY WITH BLUSTERY
WEST TO NORTHWEST WINDS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
330 PM CDT SUN MAY 17 2015
.SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM.
THE HRRR MODEL HAS BEEN CONSISTENT TODAY AND SO FAR CORRECT. OTHER
MESO MODELS ARE SIMILAR. A LINE OF SHOWERS AND THUNDERSTORMS WAS
ORIENTED ROUGHLY NORTH TO SOUTH ACROSS THE CENTRAL MKX FORECAST AREA
AT 2 PM THIS AFTERNOON. THIS LINE IS SLOWLY TRACKING EAST WITH MID
LEVEL VORTICITY ADVECTION. THESE ARE WORKING OFF THE HIGHER CAPE
AXIS THAT DEVELOPED OVER INLAND WI AREAS AND ALSO WEAK SURFACE
CONVERGENCE. THE CONVECTION IS LOW-TOPPED SINCE MID LEVEL LAPSE
RATES ARE WEAK. THEREFORE... MANY OF THE ECHO TOPS ARE BENEATH THE
FREEZING LEVEL OF 12.5 KFT AND ARE NOT EVEN PRODUCING THUNDER.
SEVERAL CELLS HAVE TOPS AROUND 20 KFT AND WE ARE SEEING CLOUD TO
GROUND LIGHTNING STRIKES WITH THEM.
PER THE HRRR AND OTHER MESO MODELS... THESE SHOWERS WILL CONTINUE
EAST THROUGH 6 PM... ALL THE WAY THROUGH MILWAUKEE. EXPECT HEAVY
DOWNPOURS. BRIEF LOCALIZED FLOODING IS POSSIBLE IN URBAN AREAS.
THERE IS A BREAK BEHIND THIS LINE OF SHOWERS AND STORMS LATE THIS
AFTERNOON. LOOK FOR GUSTY SOUTH-SOUTHWEST WINDS AS THE LOW LEVELS
MIX OUT AND DEWPOINTS DROP TO AROUND 60. CAPE/INSTABILITY WILL LOWER
IN THIS AREA. 0-6KM BULK SHEAR WILL REMAIN HIGH... AROUND 40 KT.
THERE IS ONE MORE CHANCE FOR STORMS ACROSS SOUTHERN WI THIS
EVENING... BUT THE CHANCE IS BECOMING VERY LOW. THE HRRR... NAMNEST
AND OTHER MESO MODELS ARE SHOWING QUITE A DRY SCENARIO FOR OUR AREA.
THE FEATURE WE HAVE BEEN FOCUSING OUR ATTENTION ON FOR SEVERE
POTENTIAL IS AN UPPER LEVEL WAVE AND A SURFACE PRE-FRONTAL TROUGH
ASSOCIATED WITH AN OCCLUDING LOW PRESSURE SYSTEM OVER THE EASTERN
DAKOTAS AND WEST CENTRAL MN. THE UPPER WAVE NOW LOOKS LIKE IT WILL
COME THROUGH SOUTHERN WI A LITTLE AHEAD OF THE PRE-FRONTAL TROUGH...
SO DEVELOPMENT OF STORMS WILL BE HARDER TO ACHIEVE. IF ANY STORMS
DEVELOP... THE CAPE WILL BE MARGINAL AND SHEAR WILL BE HIGH. THUS...
THERE IS STILL A SMALL RISK FOR SEVERE. SPC STILL HAS OUR AREA IN A
SLIGHT RISK FOR SEVERE STORMS.
SKIES SHOULD CLEAR LATE THIS EVENING WITH THE DRY AIR WRAPPING INTO
SOUTHERN WI AS THE SURFACE LOW TRACKS INTO NORTHEAST MN. WINDS WILL
SHIFT TO THE SW AND WEST TOWARD MORNING.
.MONDAY...FORECAST CONFIDENCE HIGH.
THE SURFACE/925MB COLD FRONT WILL TRACK THROUGH SOUTHERN WI DURING
THE DAY MONDAY. IT WILL BE SLOW TO REACH SOUTHEAST WI... THUS MAX
TEMPS WILL BE IN THE MID 70S THERE. THE DELLS AREA WILL BE COOLEST
WITH HIGHS AROUND 60. EXPECT BRISK AND GUSTY WEST WINDS DUE TO A
STRONG PRESSURE GRADIENT OVER THE REGION.
MONDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
THE UPPER LOW OVER NRN MN WILL BECOME AN OPEN WAVE AND MOVE ACROSS
LAKE SUPERIOR AND INTO ONTARIO CANADA MON NT. A WEAKER SHORTWAVE
TROUGH WILL ALSO MOVE ACROSS CENTRAL WI DURING THAT TIME. THE
SHORTWAVE WILL LIKELY AID IN BROKEN STRATUS SHIFTING SOUTH INTO S
WI ALONG WITH THE NWLY SFC FLOW AND COLD ADVECTION. NLY SFC FLOW
WILL CONTINUE INTO TUE BUT WITH WEAKENING COLD ADVECTION. DAYTIME
HEATING AND DRIER AIR SHOULD BE ENOUGH TO SCATTER OUT THE STRATUS
DECK. HOWEVER HIGH TEMPS WILL REMAIN WELL BELOW NORMAL WITH 925 MB
TEMPS ONLY WARMING TO 5-7C.
AN UPPER LOW OVER THE WRN USA WILL THEN OPEN UP AS A SHORTWAVE
TROUGH AND MOVE TOWARD WI FOR WED. DESPITE MID LEVEL FRONTOGENESIS
OVER THE REGION...KEPT THE FCST DRY AS MUCH OF THE LOW TO MID
LEVEL WARM...MOIST ADVECTION STAYS TO THE SOUTH. THUS EXPECT MO
CLOUDY SKIES FROM MIDDLE TO HIGH CLOUDS. THE CLOUDS WILL KEEP THE
HIGH TEMPS MAINLY IN THE 50S FOR THE 2ND DAY IN A ROW.
.LONG TERM...
THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM.
THE SRN PERIPHERY OF AN UPPER TROUGH WILL MOVE ACROSS THE NORTHERN
AND EASTERN GREAT LAKES THU-FRI. THIS IS EXPECTED TO BRING A WEAK
AND DRY BACKDOOR COLD FRONT ACROSS SRN WI ON FRI. HIGH PRESSURE
WILL THEN FOLLOW FROM THE NORTHERN GREAT LAKES TO THE EASTERN
GREAT LAKES FOR FRI-SAT. FOR SAT NT AND SUN AN UPPER TROUGH WILL
EJECT NEWD TOWARD WI FROM THE 4 CORNERS REGION ALONG WITH ITS SFC
TROUGH. A GOOD SURGE OF WARM...MOIST ADVECTION AND SHOWERS/TSTORMS
ARE EXPECTED. TEMPS WILL RETURN TO NEAR NORMAL FOR THE THU-SUN
PERIOD.
&&
.AVIATION/00Z TAFS/...
AN AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL WI SHOULD
EXPAND AS IT TRACKS INTO SOUTHEAST WI THROUGH 6 PM. THIS WILL BE
ABOUT A 2 HOUR PERIOD OF MODERATE TO HEAVY RAIN AND OCCASIONAL
THUNDER.
LOOK FOR A QUIET PERIOD OF WEATHER LATE THIS AFTERNOON. THERE IS ONE
MORE SMALL CHANCE FOR THUNDERSTORMS EARLY THIS EVENING... BUT THAT
CHANCE IS NOW LOOKING VERY LOW.
THE RISK FOR SEVERE WEATHER HAS DECREASED... BUT ISOLATED SEVERE
STORMS ARE STILL POSSIBLE.
LOOK FOR CLEARING SKIES OVERNIGHT. GUSTY WEST WINDS AND SCATTERED TO
BROKEN VFR CUMULUS CLOUDS EXPECTED MONDAY.
&&
.MARINE...
DENSE FOG ADVISORY WAS EXTENDED UNTIL 00Z/ 7PM THIS EVENING DUE TO
PERSISTENT SOUTHEAST WINDS AND WARM AND HUMID AIR OVER THE LAKE.
INCREASING SOUTH TO SOUTHWEST WINDS SHOULD PUSH ANY LINGERING FOG
OUT OF THE NEARSHORE WATERS THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...DENSE FOG ADVISORY UNTIL 7 PM CDT THIS AFTERNOON FOR LMZ643>646.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
303 PM CDT SUN MAY 17 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 303 PM CDT SUN MAY 17 2015
MAIN CONCERN IS SEVERE THREAT LATE THIS AFTERNOON INTO THIS
EVENING.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS UPPER LEVEL LOW/TROUGH
OVER EASTERN SOUTH DAKOTA AND WESTERN MINNESOTA...IN ADDITION A
SHORTWAVE TROUGH OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA.
LATEST 19Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTHEAST
NORTH DAKOTA AND WEST CENTRAL MINNESOTA...WITH A COLD FRONT
EXTENDING SOUTH INTO WESTERN IOWA. LATEST SATELLITE IMAGERY SHOWS
STRATUS OVER FORECAST AREA BECOMING MORE CELLUAR AND SCATTERED
SHOWERS DEVELOPED OVER NORTH CENTRAL WISCONSIN AND PARTS OF
SOUTHEAST MINNESOTA PER LATEST ARX RADAR.
WITH THE STRATUS DECK OVER MUCH OF THE REGION THROUGH EARLY
AFTERNOON HOURS...THIS HAS LIMITED INSTABILITY OVER FORECAST AREA
THIS AFTERNOON...WITH THE 17.19Z LAPS SHOWING 200-800 J/KG OVER
FORECAST AREA AND AROUND 1000-1200 J/KG ALONG AND JUST AHEAD OF
THE COLD FRONT. THE LATEST SPC MESOSCALE ANALYSIS INDICATES 40
KNOTS OF 0-6KM SHEAR OVER FORECAST AREA...WITH THE BEST SHEAR IN
THE 0-3KM SHEAR PER 17.18Z RAP OF 30 TO 40 KNOTS ALONG AND AHEAD
OF SURFACE FRONT. SPC MESOSCALE 0-1KM SHEAR INDICATES ABOUT 10 TO
20 KNOTS ALONG AND AHEAD OF COLD FRONT. WITH MINIMAL INSTABILITY
AND SHEAR DECREASING OVER FORECAST AREA...SEVERE THREAT OVER
FORECAST AREA HAS DECREASED. HOWEVER CANNOT RULE OUT AN ISOLATED
SEVERE THUNDERSTORM WITH DAMAGING WINDS...LARGE HAIL OR POSSIBLY
AN ISOLATED TORNADO LATE THIS AFTERNOON INTO THIS EVENING.
MONDAY...FORECAST AREA REMAINS UNDER THE INFLUENCE OF THE UPPER
LEVEL LOW/TROUGH OVER SOUTHERN ONTARIO AND LAKE SUPERIOR. THE
17.12Z GFS/NAM INDICATE COLD AIR ADVECTING INTO THE FORECAST
AREA...WITH 925MB TEMPERATURES FALLING TO 0 TO MINUS 2 DEGREES
CELSIUS OVER THE FORECAST AREA. HIGH TEMPERATURES ARE EXPECTED TO
BE WELL BELOW NORMAL...WITH READINGS IN THE UPPER 40S TO LOWER 60S
ACROSS THE FORECAST AREA. TIGHT PRESSURE GRADIENT WILL ALLOW FOR
WINDS TO BE SUSTAINED AT 15 TO 20 KNOTS AND GUSTS OF 20 TO 30
KNOTS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN MAY 17 2015
TUESDAY INTO WEDNESDAY...SURFACE RIDGE BUILDS INTO MUCH OF MINNESOTA
AND NORTHERN WISCONSIN. SUBSIDENCE UNDERNEATH THE RIDGE SHOULD ALLOW
FOR DRY WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES TUESDAY AND
TUESDAY NIGHT. PATCHY TO AREAS OF FROST IS POSSIBLE ACROSS PARTS OF
CENTRAL WISCONSIN TUESDAY NIGHT INTO WEDNESDAY MORNING. MID TO HIGH
CLOUDS STREAMING AHEAD OF SHORTWAVE TROUGH SOUTHWEST OF FORECAST
AREA MAY NOT ALLOW TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE
30S. TIMING OF MOISTURE ABOVE 700MB WILL BE THE BIGGEST FACTOR AND
THIS IS EVIDENT BY THE 17.12Z GFS/NAM.
WEDNESDAY...SHORTWAVE TROUGH FLATTENS UPPER LEVEL SHORTWAVE RIDGE
WEDNESDAY OVER NEBRASKA AND IOWA. WITH DRY AIRMASS IN PLACE OVER
FORECAST AREA AND THE DEEPER FORCING/LIFT ASSOCIATED WITH SHORTWAVE
TROUGH SOUTH OF FORECAST AREA...HIGHER PRECIPITATION/SHOWER
CHANCES WILL REMAIN MAINLY SOUTH OF FORECAST AREA WEDNESDAY.
HOWEVER...THE 17.12Z GFS/NAM SUGGEST 500-300MB PV ADVECTION ALONG
THE MINNESOTA AND IOWA BORDER DURING THE DAY WEDNESDAY. WILL
INTRODUCE A SMALL PRECIPITATION CHANCE OVER THE EXTREME SOUTH PART
OF THE FORECAST AREA...AS THE 17.12 GFS/NAM DEVELOP LIGHT QPF...A
HUNDREDTH OR TWO...OVER THE EXTREME SOUTHERN PART OF THE FORECAST
AREA.
MAIN FORECAST CONCERNS FROM WEDNESDAY NIGHT INTO MEMORIAL DAY
WEEKEND ARE PRECIPITATION CHANCES FOR MEMORIAL DAY WEEKEND. THE
17.12Z GFS/ECMWF/GEM ARE IN GOOD AGREEMENT IN BUILDING IN
SHORTWAVE/SURFACE RIDGE INTO THE UPPER MIDWEST AND GREAT LAKES
REGION WEDNESDAY NIGHT INTO FRIDAY PROVIDING DRY WEATHER AND
SLIGHTLY TO NEAR NORMAL TEMPERATURES BOTH DAYS. FOCUS TURNS TO
MEMORIAL DAY WEEKEND...WHERE THE 17.12Z GFS/ECMWF ARE IN GOOD
AGREEMENT IN EJECTING PIECES OF ENERGY OUT OF UPPER LEVEL LOW/TROUGH
OVER THE SOUTHWEST UNITED STATES INTO THE CENTRAL UNITED STATES.
BOTH THE 17.12Z GFS/ECMWF SHOW INCREASING LOW LEVEL JET/MOISTURE
TRANSPORT/CONVERGENCE AND LIFT/FORCING SATURDAY INTO SUNDAY INTO THE
FORECAST AREA. WILL CONTINUE TO TREND OF SHOWERS AND THUNDERSTORMS
SATURDAY INTO SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1245 PM CDT SUN MAY 17 2015
LOW PRESSURE LIFTING THROUGH THE REGION WILL PRODUCE SCATTERED
SHOWERS AND THUNDERSTORMS AND MVFR TO IFR CONDITIONS AT TIMES.
LOOK FOR A COLD FRONT TO SWEEP ACROSS THE TAF SITES THIS EVENING
WITH SOUTHWEST WINDS INCREASING TO 15 TO 17 KTS WITH GUSTS OF 25
TO 30 KTS POSSIBLE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...WETENKAMP
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED
LOW PRESSURE SYSTEM SPINNING OVER THE EASTERN DAKOTAS. SHORTWAVES
ARE ROTATING NORTHWARD AHEAD OF THIS OCCLUDED CYCLONE...THE
STRONGEST OF WHICH IS LOCATED OVER EASTERN IOWA. A PWAT AXIS IS
MOVING ACROSS WISCONSIN EARLY THIS AFTERNOON...WHICH COMBINED WITH
MOISTURE CONVERGENCE...IS CONTRIBUTING TO SCATTERED SHOWER
DEVELOPMENT OVER CENTRAL WISCONSIN. CLOUD COVER HAS SIGNIFICANTLY
SLOWED THE HEATING CURVE SO FAR TODAY...KEEPING ML CAPES BELOW 200
J/KG. WITH SHOWER COVERAGE EXPECT TO INCREASE THROUGH THE
AFTERNOON...IT WILL BE TOUGH TO SEE MUCH OF AN INCREASE OF
INSTABILITY. STILL THOUGH...RADAR ECHOES SUGGEST SOME THUNDERSTORMS
WILL BE POSSIBLE...AND ANY STORMS COULD BRING DOWN STRONG WINDS FROM
ALOFT. WILL HAVE TO KEEP A MENTION OF ISOLATED DAMAGING WINDS
THROUGH EARLY THIS EVENING. OTHERWISE...THE LATEST HRRR CONGEALS THE
SHOWER ACTIVITY INTO BAND AND PROGRESSES IT ACROSS THE FORECAST AREA
FOR THE REST OF THE AFTERNOON.
TONIGHT...LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN
MINNESOTA...WHILE A COLD FRONT WILL PUSH EAST THROUGH ALL BUT FAR
EASTERN WISCONSIN OVERNIGHT. THOUGH SHORTWAVE ENERGY WILL BE
ROTATING NORTHEAST OVER NORTHWEST WISCONSIN THROUGH THE
EVENING...CONCERNED THAT STRONG DRYING AND INCREASING CAPPING IN THE
MID-LEVELS WILL EVEN FURTHER LIMIT THUNDERSTORM POTENTIAL FOR THE
FIRST COUPLE HOURS IN THE EVENING. WILL KEEP A MENTION OF ISOLATED
DAMAGING WINDS THROUGH 02Z IN CASE SOME THUNDERSTORMS MAKE A RUN
INTO N-C WISCONSIN FROM MINNESOTA. ONCE THE THREAT OF STORMS ENDS...MODELS
SHOW CLEARING TAKING PLACE UNTIL LOW CLOUDS FLOOD EAST BEHIND THE
COLD FRONT LATE TONIGHT. LOW TEMPS NEAR 60 OVER THE EAST...BUT
COOLING TO NEAR 50 OVER THE WEST.
MONDAY...OCCLUDED LOW PRESSURE WILL BE WEAKENING AS IT MOVES TO THE
EAST ACROSS LAKE SUPERIOR. WEST WINDS ON THE SOUTHERN FLANK OF THE
LOW WILL BE COLD ADVECTING THROUGH THE DAY...WHILE PUSHING IN WRAP
AROUND MOISTURE. SHOULD SEE AMPLE CLOUD COVER OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THROUGH THE DAY...BUT EAST-CENTRAL WISCONSIN
WILL LIKELY SEE SOME SUN IN THE MORNING BEFORE CLOUDS INCREASE IN
THE AFTERNOON. WITH THE SUNSHINE...TEMPS SHOULD WARM TO NEAR 70 IN
THE EAST...BUT ONLY INTO THE MID AND UPPER 50S OVER THE WEST.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK...DRY
AND MILDER CONDITIONS FOR THE LATTER HALF...AND A POSSIBLE RETURN
TO WET WEATHER LATER IN THE MEMORIAL DAY WEEKEND...ARE THE MAIN
FCST CONCERNS.
THE REMNANTS OF THE UPPER LOW WILL TRACK ACROSS NORTHERN LAKE SUPERIOR
ON MONDAY NIGHT...FOLLOWED BY A S/W TROF PASSING NORTH OF WI ON TUESDAY.
UNSEASONABLY COLD AIR (H8 TEMPS -8 TO -10 C) WILL FLOW INTO THE REGION
ON NNW WINDS...SETTING THE STAGE FOR SOME LAKE-ENHANCED SHOWERS OVER
NC WI. LOW-LEVEL TEMPS AND THICKNESSES SUPPORT A MIX THEN CHANGEOVER
TO SNOW LATE MONDAY NIGHT INTO TUESDAY MORNING...WITH LITTLE OR NO
ACCUMULATION EXPECTED. ANY LINGERING PCPN SHOULD END TUESDAY AFTERNOON
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION.
HIGH PRESSURE WILL COVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. STILL
EXPECTING FROST TUESDAY NIGHT...BUT GETTING A LITTLE CONCERNED ABOUT
THE POSSIBILITY OF THICKER HIGH LEVEL CLOUDS...DUE TO THE PRESENCE
OF A STRONG JET STREAK OVER THE REGION. RIGHT NOW...HAVE JUST
BUMPED UP CLOUD COVER A BIT OVER C/EC WI...BUT KEPT MOSTLY CLEAR
SKIES OVER NORTHERN WI. WILL CONTINUE TO CARRY WIDESPREAD FROST OR
FREEZE CONDITIONS OVER NORTHERN WI...AND PATCHY FROST OVER MOST OF
C/EC WI.
A WEAK BACK DOOR COLD FRONT WILL SAG THROUGH THE FORECAST AREA THURSDAY
INTO THURSDAY NIGHT...BUT WILL NOT HAVE ANY MOISTURE TO WORK WITH...SO
DRY WEATHER WILL PREVAIL. BEHIND THE FRONT...CANADIAN HIGH PRESSURE
WILL REESTABLISH ITSELF OVER THE WESTERN GREAT LAKES...AND IS EXPECTED
TO LINGER INTO SATURDAY. ABUNDANT SUNSHINE SHOULD BRING A RETURN TO
NEAR NORMAL TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
AN UPPER TROF...LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
IMPACT THE REGION FROM SATURDAY NIGHT INTO SUNDAY. GULF MOISTURE
IS EXPECTED TO FLOW INTO THE REGION AHEAD OF THE FRONT...WITH
PRECIPITABLE WATER VALUES REACHING 1.00-1.25 INCHES. HAVE RAMPED
POPS UP TO LIKELY FOR SUNDAY. THE ECMWF PULLS MOST OF THE PCPN OUT
OF THE REGION SUNDAY EVG...WHILE THE GFS HANGS ONTO SIGNIFICANT
QPF INTO MEMORIAL DAY...SO FCST CONFIDENCE WANES BEYOND SUNDAY.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1215 PM CDT SUN MAY 17 2015
COMPLICATED WEATHER SCENARIO UNFOLDING TODAY AS LOW PRESSURE
MOVES NORTHEAST OVER MINNESOTA...AND WARM FRONT LIFTS NORTH OVER
CENTRAL WISCONSIN. CIGS WITHIN A MOISTURE LADEN AIRMASS WILL
SLOWLY IMPROVE THIS AFTERNOON AS SHOWERS MOVE IN FROM THE WEST.
WITH FURTHER DAYTIME HEATING...THUNDERSTORMS REMAIN POSSIBLE MID-AFTERNOON
INTO THE EVENING AHEAD OF A COLD FRONT...WITH POTENTIAL FOR
DAMAGING WINDS WITHIN ANY STORMS. THE STORMS SHOULD DISSIPATE BY
MID-EVENING AND SKIES SHOULD PARTIALLY CLEAR INTO THE OVERNIGHT
PERIOD. THEN A COLD FRONT WILL MOVE THROUGH THE REGION LATE
TONIGHT. MVFR CLOUDS WILL RETURN INTO CENTRAL AND NORTH- CENTRAL
WISCONSIN BEHIND THE FRONT AND LINGER THROUGH THE END OF THE TAF
PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC