Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/16/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
745 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... VIGOROUS AND UNSEASONABLY COOL UPPER LEVEL PACIFIC LOW
CONTINUED TO MOVE INLAND AND INTO THE SOUTHWESTERN STATES THIS
EVENING...WITH H5 CORE TEMPS RUNNING AROUND MINUS 22C OVER SERN
CA/FAR SRN NV. MAIN VORT LOBE PIVOTING AROUND THE SOUTHERN SIDE OF
THE LOW WAS MOVING INTO WESTERN AZ EARLY THIS EVENING...AND THE 00Z
EVENING PLOTS SHOWED THE TROF AXIS NEARLY TO THE AZ/CA BORDER.
EARLIER IN THE AFTERNOON A SHORT WAVE AHEAD OF THE MAIN LOW LED TO
SCATTERED SHOWERS AND ISOLD STORMS OVER SOUTH CENTRAL AZ...BUT THAT
ACTIVITY DIMINISHED AND MOVED OFF TO THE NORTHEAST. AT 730 PM RADAR
SHOWED SHOWERS AND CONVECTION ASSOCIATED WITH THE MAIN LOW
INCREASING AND MOVING ACROSS THE SWRN AZ DESERTS...STARTING TO
APPROACH THE GREATER PHOENIX AREA FROM THE WEST. STRONG SUBSIDENCE
BEHIND THE TROF AXIS HAS BEEN SPREADING INTO SERN CA AND IR IMAGERY
AT 730 PM SHOWED SUBSTANTIAL CLEARING WEST OF THE LOWER CO RIVER
VALLEY. BASED ON RADAR/SATELLITE TRENDS AND LATEST MODEL GUIDANCE
ANOTHER ROUND OF SHOWERS WILL MOVE INTO SOUTH CENTRAL ARIZONA AFTER
8 PM AND PERSIST THROUGH LATE EVENING OR AROUND MIDNIGHT BEFORE
TAPERING OFF AS THE LOW MOVES EAST AND THE VORT LOBE PUSHES THROUGH
CENTRAL ARIZONA. LATEST SPC MESOANALYSIS GRAPHICS SHOWED BETWEEN 100
AND 250 J/KG OF MLCAPE OVER SRN AZ SO WE MAY SEE AN ISOLATED
THUNDERSTORM MIXED IN WITH THE WIDER AREA OF SHOWERS THIS EVENING.
CURRENT FORECASTS HAVE BEEN TWEAKED TO REFLECT CURRENT
SKY/POP/WEATHER TRENDS BUT BASIC FORECAST IDEAS HAVE NOT CHANGED.
STILL WAITING FOR ROUND 2 OF THE SHOWERS LATER THIS EVENING...BUT WE
DO NOT EXPECT HEAVY RAINS TO OCCUR AND MOST RAIN TOTALS WITH THE
SECOND BATCH SHOULD BE BELOW ONE HALF OF AN INCH. SOMEWHAT HIGHER
TOTALS ARE POSSIBLE NORTH AND EAST OF PHOENIX...OVER HIGHER TERRAIN
LOCATIONS.
.PREVIOUS 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... FIRST
BATCH OF SHOWERS/STORMS WITH LOWER CIGS MOVED OFF TO THE NE EARLIER
THIS EVENING...BUT WE EXPECT A SECOND BATCH OF CONVECTION MOVING IN
TO THE CENTRAL DESERTS AFTER 8-9PM...PERSISTING THROUGH MIDNIGHT OR
SO BEFORE DIMINISHING AND MOVING OFF TO THE EAST. ISOLD STORMS ARE
POSSIBLE...AND SHOULD A STORM OCCUR WE COULD SEE CIGS BRIEFLY LOWER
TO AROUND 3K FEET...BUT MOSTLY CIGS SHOULD STAY AOA 4-5K FEET FOR
THE REST OF THE EVENING AND INTO THE EARLY MORNING SATURDAY. WINDS
WILL FAVOR THE WEST THRU 10Z OR SO BUT WILL LIKELY BE SQUIRRELY AND
VARIABLE WHEN THE SHOWERS/STORMS AND THEIR ASSOCIATED OUTFLOWS MOVE
THRU THE AREA. BY 12Z MOST OF THE WEATHER SHOULD BE OVER FOR THE TAF
SITES AND WE SHOULD SEE LINGERING CU/SC DECKS THRU SATURDAY
AFTERNOON WITH BASES MOSTLY 4-6K AND 8-10K FEET. CIGS ARE POSSIBLE
LATE MORNING THRU AFTERNOON BUT FEEL THAT SCT DECKS WILL BE MORE
COMMON.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND
KBLH... STRONG SUBSIDENCE/DVV MOVING THRU SERN CA BEHIND THE PASSING
UPPER TROF...AND WE WILL SEE SIGNIFICANT CLEARING AT THE TAF SITES
BY 05Z OR SO. MOST CLOUD DECKS WILL BE SCATTERED AFTER MIDNIGHT WITH
BASES AOA 6KT FEET. WINDS TO FAVOR THE WEST AT KIPL OVERNIGHT AND
INTO THE MORNING ON SATURDAY. WINDS AT KBLH MORE VARIABLE NEXT 24
HOURS BUT SHOULD FAVOR THE SOUTH TO THE SOUTHWEST.
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.
&&
$$
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DISCUSSION...CB
PREVIOUS DISCUSSION...LEINS/VASQUEZ
AVIATION...CB
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 AM MST THU MAY 14 2015
.SYNOPSIS...STRONG AND GUSTY WINDS WILL OCCUR INTO FRIDAY AHEAD OF A
STRONG LOW PRESSURE SYSTEM APPROACHING FROM THE WEST. THIS SYSTEM
WILL ALSO BRING A GOOD CHANCE OF SHOWERS...ISOLATED THUNDERSTORMS
AND COOLER TEMPERATURES FRIDAY INTO SATURDAY. EXPECT DRY CONDITIONS
AND MUCH WARMER TEMPERATURES EARLY NEXT WEEK.
&&
.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY INDICATED MOSTLY CLOUDY
SKIES DUE TO CIRRIFORM CLOUDS FROM THE TUCSON METRO AREA EWD TO THE
NEW MEXICO BORDER. CLEARING SKIES WERE NOTED ACROSS THE TOHONO
O`ODHAM NATION...BUT CUMULOFORM CLOUDS HAD DEVELOPED DURING THE PAST
HOUR OR SO ACROSS FAR WRN PIMA COUNTY. SURFACE WINDS VALID 16Z WERE
GENERALLY SLY AT 10-20 MPH WITH GUSTS TO NEAR 30 MPH.
DEEP UPPER TROUGH NEAR THE WEST COAST WITH A TIGHT MID-LEVEL
PRESSURE GRADIENT ACROSS SE ARIZONA WILL PRODUCE WINDY CONDITIONS
TODAY. A WIND ADVISORY IS IN EFFECT UNTIL 7 PM MST THIS EVENING FOR
LOCATIONS SE OF TUCSON. PLEASE REFER TO AWIPS PRODUCT PHXNPWTWC /WMO
HEADER WWUS75 KTWC/ FOR FURTHER DETAIL. OTHERWISE...PRECIP-FREE
CONDITIONS WILL OCCUR TODAY AHEAD OF THIS STRONG LOW PRESSURE
SYSTEM.
BASED ON THE 14/12Z NAM/GFS AND RUC HRRR SOLUTIONS... THERE ARE NO
UPDATES PLANNED AT THIS TIME. PLEASE REFER TO THE ADDITIONAL
SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 15/18Z.
EXPECT A FEW TO SCATTERED CLOUDS AT 6-12K FT AGL AND BROKEN TO
OVERCAST CLOUD DECKS ABOVE 20K FT AGL INTO FRIDAY MORNING. STRONG
AND GUSTY WINDS WILL OCCUR TODAY. SURFACE WIND THE REST OF THIS
MORNING WILL BE SLY/SWLY AT 14-22 KTS WITH GUSTS OF 25-35 KTS...THEN
SPEEDS INCREASING TO 20-30 KTS WITH GUSTS OF 35-40 KTS THIS
AFTERNOON. SURFACE WIND DECREASING THIS EVENING THOUGH THERE WILL BE
AN INCREASED SLY/SWLY COMPONENT OVERNIGHT...ESPECIALLY NEAR KDUG AND
KFHU. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A STRONG STORM SYSTEM WILL APPROACH AND MOVE ACROSS
THE REGION RESULTING IN STRONG AND GUSTY WINDS TODAY AND
FRIDAY...FOLLOWED BY A CHANCE OF SHOWERS AND THUNDERSTORMS LATE
FRIDAY INTO SATURDAY. ALTHOUGH WINDY CONDITIONS ARE EXPECTED ACROSS
MUCH OF THE AREA TODAY AND FRIDAY...THE STRONGEST WINDS WILL OCCUR
ACROSS COCHISE COUNTY.
WIND SPEEDS ARE EXPECTED TO EXCEED CRITICAL FIRE WEATHER THRESHOLDS
TODAY. HOWEVER...MINIMUM RELATIVE HUMIDITY VALUES WILL BE BORDERLINE
TODAY...AND THEN INCREASING MOISTURE IS EXPECTED ON FRIDAY. CRITICAL
FIRE WEATHER CONDITIONS MAY BE BRIEFLY MET FOR AN HOUR OR TWO THIS
AFTERNOON AT THE LOWER ELEVATIONS...ALTHOUGH WIDESPREAD AND/OR LONG
LIVED CONDITIONS ARE NOT EXPECTED. EXPECT DRY CONDITIONS WITH MUCH
WARMER TEMPERATURES EARLY NEXT WEEK.
&&
.PREV DISCUSSION...MODELS INDICATE THAT THE LOW PRESSURE SYSTEM OFF
THE CALIFORNIA COAST WILL CONTINUE MOVING EAST TODAY...WITH A VORT
MAX ROTATING THROUGH THE BASE OF THE TROUGH ACROSS WESTERN ARIZONA
BY LATE THIS AFTERNOON. AS A RESULT...EXPECTING A CONSIDERABLE
INCREASE IN WINDS TODAY IN ADVANCE OF THIS SYSTEM. THAT SAID...A
WIND ADVISORY WAS ALREADY HOISTED BY THE DAY SHIFT YESTERDAY. A WIND
ADVISORY IS ALSO IN EFFECT FOR FRIDAY AS WELL FOR THE SAME GENERAL
AREA...ALTHOUGH SLIGHTLY MORE REAL ESTATE FARTHER TO THE WEST THAN
TODAY. EVEN THOUGH WINDS WILL EASILY EXCEED RED FLAG CRITERIA FOR
MOST AREAS TODAY...THE MINIMUM RELATIVE HUMIDITIES STILL WILL BE THE
FACTOR THAT LIMITS DURATIONS THAT RED FLAG CONDITIONS WILL BE MET
TODAY (FOR MORE INFO SEE THE FIRE WEATHER SECTION).
THE PRECIPITATION WILL BEGIN EARLY FRIDAY WITH JUST ISOLATED
MOUNTAIN ACTIVITY THROUGH THE MORNING HOURS. BY THE EVENING HOURS ON
FRIDAY EXPECT SCATTERED DESERT/VALLEY SHOWERS AND ISOLATED
THUNDERSTORMS...WHILE THE MOUNTAINS WILL SEE GOOD CHANCE TO NUMEROUS
SHOWERS AND SNOW SHOWERS. FOR THE OVERNIGHT PERIOD FROM MIDNIGHT
FRIDAY NIGHT TO AROUND SUNRISE SATURDAY...EXPECT NUMEROUS SHOWERS
AND ISOLATED THUNDERSTORMS FROM NORTH OF NOGALES THROUGH THE TUCSON
METRO AND NORTH AND EAST TOWARD PINAL...GRAHAM AND GREENLEE
COUNTIES. BY SATURDAY MORNING AND CONTINUING THROUGH LATE SATURDAY
PRECIPITATION CHANCES WILL CONTINUE TO DECREASE WITH A RETURN TO DRY
WEATHER BY SATURDAY NIGHT INTO SUNDAY. SOME SNOW IN THE HIGHER
ELEVATIONS EXPECTED WITH THIS SYSTEM AS SNOW LEVELS FALL TO AROUND
7000-7500 FEET BY EARLY SATURDAY MORNING. SNOW AMOUNTS EXPECTED TO
BE THE GREATEST OVER THE WHITE MOUNTAINS WITH NEARLY 5 INCHES
EXPECTED AND ONLY 2 TO 4 INCHES FOR THE SANTA CATALINA AND RINCON
MOUNTAINS OF EASTERN PIMA COUNTY AND THE GALIURO AND PINALENO
MOUNTAINS OF GRAHAM COUNTY.
DRY WEATHER RETURNS SUNDAY AND WILL CONTINUE THROUGH THE MIDDLE OF
NEXT WEEK WITH A SLIGHT WARMING TREND BEGINNING ON SUNDAY.
FOR TUCSON...HIGH TEMPERATURES GENERALLY 6 TO 8 DEGS BELOW NORMAL
TODAY...THEN 15 TO NEAR 20 DEGS BELOW NORMAL FOR FRIDAY AND
SATURDAY. THEREAFTER...HIGHS AROUND 4 TO 7 DEGS BELOW NORMAL. LOW
TEMPS WILL BE BELOW NORMAL THROUGH THE ENTIRE FORECAST
PERIOD...ALTHOUGH THE COOLEST MORNINGS WILL OCCUR OVER THE
WEEKEND...WHEN THEY WILL RANGE FROM 6 TO 8 DEGS BELOW NORMAL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR AZZ507-508-512-513.
WIND ADVISORY FROM NOON TO 7 PM MST FRIDAY FOR AZZ503-507-508-
511>513-515.
&&
$$
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
908 AM PDT THU MAY 14 2015
.SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE
THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS
SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY
MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL
LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK.
TEMPERATURES WILL BE COOLER THAN NORMAL THROUGH THE PERIOD.
&&
.DISCUSSION...AS OF 9:08 AM PDT THURSDAY...LOCAL RADAR IS SHOWING
SHOWERS OVER THE COASTAL WATERS THAT ARE SLOWLY MOVING EASTWARD
TOWARDS THE COAST. THERE HAVE BEEN A FEW LIGHTNING STRIKES WEST OF
THE MONTEREY/SAN LUIS OBISPO COUNTY LINE DURING THE PAST HOUR.
EXPECT SHOWER ACTIVITY TO MOVE ONSHORE LATER THIS MORNING WITH A
SLIGHT CHANCE OF THUNDERSTORMS THROUGH THE EVENING. RAINFALL
TOTALS ARE NOT EXPECTED TO BE LARGE...UP TO A THIRD OF AN INCH
IS POSSIBLE...BUT COULD TOP OUT AROUND A HALF INCH IN AREAS OF
HEAVIER SHOWERS...MAINLY OVER COASTAL MONTEREY COUNTY. THE HRRR IS
STILL INDICATING VERY SPOTTY RAINFALL AMOUNTS WITH SOME AREAS IN
THE EAST BAY POSSIBLY GETTING UP TO A HALF INCH. THE MOST LIKELY
SCENARIO IS A FEW SPOTS WILL GET MUCH MORE THAN EXPECTED WHILE
OTHER PLACES GET LITTLE TO NO RAINFALL. SHOWERS ARE EXPECTED TO LINGER
INTO THE OVERNIGHT HOURS AND SLOWLY DIMINISH ON FRIDAY.
THE UPPER LOW WILL CONTINUE TO MOVE TO THE SOUTH ON FRIDAY WITH
RAIN MOVING INLAND OVER THE LOS ANGELES BASIN FRIDAY MORNING. OUR
AREA WILL SEE COOL TEMPERATURES THROUGH THE WEEKEND AS A LONG-WAVE
TROUGH REMAINS OVER THE WEST. THIS TROUGH PATTERN WILL MAINTAIN
THROUGH NEXT WEEK AS WELL WITH A FEW IMPULSES MOVING THROUGH FROM
TIME TO TIME. RIGHT NOW NONE OF THESE ARE EXPECTED TO BRING ANY
PRECIPITATION TO THE AREA...HOWEVER...COOLER THAN NORMAL
TEMPERATURES WILL BE THE RULE.
&&
.AVIATION...AS OF 4:30 AM PDT THURSDAY...CLOUDS ARE LOWERING WITH
THE APPROACH OF AN UPPER LEVEL LOW. RADAR IS STARTING TO DETECT
LIGHT SHOWERS OFF THE COAST AND THESE WILL MOVE INTO THE COAST BY
MID MORNING AND INLAND LATE MORNING. WINDS WILL BE LIGHT SOUTHERLY
THIS MORNING BUT WILL SWITCH TO WESTERLY IN THE AFTERNOON.
VICINITY OF KSFO...MVFR CIGS. SHOWERS AFTER 16Z. SOUTHEAST WINDS
5-10 KT SWITCHING TO THE WEST AFTER 20Z. CLOUDS DECREASING AFTER 02Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...MVFR CIGS. SHOWERS AFTER 15Z. CLOUDS
DECREASING AFTER 01Z.
&&
.MARINE...AS OF 08:21 AM PDT THURSDAY...A 1010 MB LOW OFF THE
NORTHERN CALIFORNIA COAST WILL TRACK SOUTHWARD BRINGING A SLIGHT
CHANCE OF THUNDERSTORMS TODAY AND TONIGHT. NORTHWEST WINDS WILL
INCREASE FRIDAY AND SATURDAY AS THE LOW MOVES INLAND OVER SOUTHERN
CALIFORNIA AND HIGH PRESSURE BUILDS OFF THE CALIFORNIA COAST.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: SIMS
AVIATION: W PI
MARINE: LARRY
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
433 AM PDT THU MAY 14 2015
.SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE
THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS
SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY
MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL
LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK.
COOLER THAN NORMAL TEMPERATURES WILL CONTINUE.
&&
.DISCUSSION...AS OF 3:00 AM PDT THURSDAY...KMUX RADAR THIS MORNING
IS STARTING TO PICK UP THE LEADING EDGE OF PRECIPITATION FROM A
SYSTEM OFF OUR COAST. CLOSEST ECHOES AROUND ABOUT 70 MILES TO THE
WEST OF MONTEREY WITH MORE SUBSTANTIAL RETURNS ABOUT 75 MILES WEST
OF BIG SUR. THIS VERIFIES WELL WITH THE LATEST RUN OF THE HRRR.
MODELS ARE GENERALLY IN GOOD AGREEMENT THAT RAIN WILL CONTINUE TO
ADVANCE TO THE COAST THIS MORNING AND BE NEAR LOCAL BEACHES BY MID
TO LATE MORNING. BY EARLY AFTERNOON RAIN IS EXPECTED TO BE ACROSS
OUR ENTIRE AREA. RAIN WILL ALSO CHANGE OVER TO SHOWERS BY
AFTERNOON AS THE ATMOSPHERE BECOMES MORE UNSTABLE. LIFTED VALUES
DROP AS LOW AS MINUS 2 ALONG WITH SOME WEAK CAPE NUMBERS SO
THUNDERSTORMS AND SMALL HAIL CANNOT BE RULED OUT.
RAINFALL AMOUNTS ARE STILL EXPECTED TO BE HIGHER THE FARTHER TO
THE SOUTH YOU TRAVEL WITH THE HIGHEST VALUES FOR COASTAL MONTEREY
COUNTY MOUNTAINS. THERE HALF AN INCH TO AN INCH COULD EASILY FALL.
FOR THE REST OF OUR AREA...MANY PLACES WILL LIKELY SEE A TENTH TO
A QUARTER OF AN INCH. INTERESTING TO NOTE OFF THE HRRR THAT IT
INDICATES SOME POCKETS OF HALF AN INCH TO THE EAST BY BY THE
AFTERNOON. AS IS ALWAYS THE CASE WITH SHOWERS...WE WILL LIKELY SEE
A FEW SPOTS GETTING MUCH MORE THAN EXPECTED WHILE OTHER PLACES GET
LITTLE TO NO RAINFALL. SHOWERS WILL LINGER INTO THE OVERNIGHT
HOURS AND SLOWLY DIMINISH THROUGH FRIDAY.
SYNOPTICALLY THE SYSTEM THAT WILL PROVIDE THE RAIN IS ASSOCIATED
WITH A LONGWAVE TROF THAT IS DIVING SOUTHWARD OFF THE WEST COAST.
BASED OFF THE TRACK OF THE PARENT LOW ASSOCIATED WITH THE TROF THE
NEXT ROUND OF RAIN WILL FOCUS WELL TO OUR SOUTH. PERSONS WHO HAVE
TRAVEL PLANS TO SOUTHERN CALIFORNIA ON FRIDAY SHOULD PAY VERY
CLOSE ATTENTION TO THE LATEST FORECASTS.
A MIX OF SUN AND CLOUDS ALONG WITH COOLER THAN NORMAL TEMPERATURES
WILL LIKELY GO THROUGH THE WEEKEND INTO ALL OF NEXT WEEK AS A
BROAD LONGWAVE TROF REMAINS ACROSS OUR ENTIRE REGION. MULTIPLE
DISTURBANCES WILL ROTATE THROUGH THE TROF ALTHOUGH THE VAST
MAJORITY OF ASSOCIATED RAINFALL WITH LIKELY STAY WELL OUT OF OUR
CWA. ON THE FLIP SIDE...THE UNSETTLED PATTERN WILL HELP TO LIMIT
THE MARINE LAYER.
&&
.AVIATION...AS OF 4:30 AM PDT THURSDAY...CLOUDS ARE LOWERING WITH
THE APPROACH OF AN UPPER LEVEL LOW. RADAR IS STARTING TO DETECT
LIGHT SHOWERS OFF THE COAST AND THESE WILL MOVE INTO THE COAST BY
MIDMORNING AND INLAND LATE MORNING. WINDS WILL BE LIGHT SOUTHERLY
THIS MORNING BUT WILL SWITCH TO WESTERLY IN THE AFTERNOON.
VICINITY OF KSFO...MVFR CIGS. SHOWERS AFTER 16Z. SOUTHEAST WINDS
5-10 KT SWITCHING TO THE WEST AFTER 20Z. CLOUDS DECREASING AFTER 02Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...MVFR CIGS. SHOWERS AFTER 15Z. CLOUDS
DECREASING AFTER 01Z.
&&
.MARINE...AS OF 4:30 AM PDT THURSDAY...A 1010 MB LOW OFF THE
NORTHERN CALIFORNIA COAST WILL TRACK SOUTHWARD BRINGING A SLIGHT
CHANCE OF THUNDERSTORMS TODAY AND TONIGHT. NORTHWEST WINDS WILL
INCREASE FRIDAY AND SATURDAY AS THE LOW MOVES INLAND OVER SOUTHERN
CALIFORNIA AND HIGH PRESSURE BUILDS OFF THE CALIFORNIA COAST.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: BELL
AVIATION/MARINE: W PI
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
259 AM PDT THU MAY 14 2015
.SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE
THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS
SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY
MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL
LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK.
COOLER THAN NORMAL TEMPERATURES WILL CONTINUE.
&&
.DISCUSSION...AS OF 3:00 AM PDT THURSDAY...KMUX RADAR THIS MORNING
IS STARTING TO PICK UP THE LEADING EDGE OF PRECIPITATION FROM A
SYSTEM OFF OUR COAST. CLOSEST ECHOES AROUND ABOUT 70 MILES TO THE
WEST OF MONTEREY WITH MORE SUBSTANTIAL RETURNS ABOUT 75 MILES WEST
OF BIG SUR. THIS VERIFIES WELL WITH THE LATEST RUN OF THE HRRR.
MODELS ARE GENERALLY IN GOOD AGREEMENT THAT RAIN WILL CONTINUE TO
ADVANCE TO THE COAST THIS MORNING AND BE NEAR LOCAL BEACHES BY MID
TO LATE MORNING. BY EARLY AFTERNOON RAIN IS EXPECTED TO BE ACROSS
OUR ENTIRE AREA. RAIN WILL ALSO CHANGE OVER TO SHOWERS BY
AFTERNOON AS THE ATMOSPHERE BECOMES MORE UNSTABLE. LIFTED VALUES
DROP AS LOW AS MINUS 2 ALONG WITH SOME WEAK CAPE NUMBERS SO
THUNDERSTORMS AND SMALL HAIL CANNOT BE RULED OUT.
RAINFALL AMOUNTS ARE STILL EXPECTED TO BE HIGHER THE FARTHER TO
THE SOUTH YOU TRAVEL WITH THE HIGHEST VALUES FOR COASTAL MONTEREY
COUNTY MOUNTAINS. THERE HALF AN INCH TO AN INCH COULD EASILY FALL.
FOR THE REST OF OUR AREA...MANY PLACES WILL LIKELY SEE A TENTH TO
A QUARTER OF AN INCH. INTERESTING TO NOTE OFF THE HRRR THAT IT
INDICATES SOME POCKETS OF HALF AN INCH TO THE EAST BY BY THE
AFTERNOON. AS IS ALWAYS THE CASE WITH SHOWERS...WE WILL LIKELY SEE
A FEW SPOTS GETTING MUCH MORE THAN EXPECTED WHILE OTHER PLACES GET
LITTLE TO NO RAINFALL. SHOWERS WILL LINGER INTO THE OVERNIGHT
HOURS AND SLOWLY DIMINISH THROUGH FRIDAY.
SYNOPTICALLY THE SYSTEM THAT WILL PROVIDE THE RAIN IS ASSOCIATED
WITH A LONGWAVE TROF THAT IS DIVING SOUTHWARD OFF THE WEST COAST.
BASED OFF THE TRACK OF THE PARENT LOW ASSOCIATED WITH THE TROF THE
NEXT ROUND OF RAIN WILL FOCUS WELL TO OUR SOUTH. PERSONS WHO HAVE
TRAVEL PLANS TO SOUTHERN CALIFORNIA ON FRIDAY SHOULD PAY VERY
CLOSE ATTENTION TO THE LATEST FORECASTS.
A MIX OF SUN AND CLOUDS ALONG WITH COOLER THAN NORMAL TEMPERATURES
WILL LIKELY GO THROUGH THE WEEKEND INTO ALL OF NEXT WEEK AS A
BROAD LONGWAVE TROF REMAINS ACROSS OUR ENTIRE REGION. MULTIPLE
DISTURBANCES WILL ROTATE THROUGH THE TROF ALTHOUGH THE VAST
MAJORITY OF ASSOCIATED RAINFALL WITH LIKELY STAY WELL OUT OF OUR
CWA. ON THE FLIP SIDE...THE UNSETTLED PATTERN WILL HELP TO LIMIT
THE MARINE LAYER.
&&
.AVIATION...AS OF 10:53 PM PDT WEDNESDAY...A MIX OF LOW, MID AND
HIGH CLOUDS WILL CONTINUE TO MOVE ACROSS THE REGION WITH AN
INCREASING CHANCE OF RAIN LATE TONIGHT INTO EARLY THURSDAY
MORNING. A FRONTAL BAND ASSOCIATED WITH THE APPROACHING LOW
WILL ARRIVE PARALLEL TO THE COAST THEN SWEEP ACROSS THE REGION
THURSDAY MORNING BRINGING RAIN TO THE ENTIRE AREA. WET RUNWAYS ARE
POSSIBLE AFTER 12Z THURSDAY.
VICINITY OF KSFO...VFR CIGS WILL LOWER TO AROUND 3000 FEET
OVERNIGHT WITH RAIN CHANCES INCREASING AFTER 12Z TONIGHT. LIGHT
SOUTHWESTERLY WINDS OF 5 TO 10 KT EXPECTED THROUGH LATE TONIGHT.
WINDS WILL TURN SOUTHERLY OVERNIGHT INTO THURSDAY. WET RUNWAYS
POSSIBLE AFTER 12Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CIGS WILL LOWER TO AROUND 2500
FEET OVERNIGHT WITH RAIN CHANCES INCREASING AFTER 15Z TONIGHT.
LIGHT SOUTHWESTERLY WINDS OF 5 TO 10 KT EXPECTED THROUGH LATE
TONIGHT. WINDS WILL TURN SOUTHERLY OVERNIGHT INTO THURSDAY. WET
RUNWAYS POSSIBLE AFTER 15Z.
&&
.MARINE...AS OF 9:07 PM PDT WEDNESDAY...LIGHT SOUTHERLY WINDS WILL
CONTINUE TONIGHT AS A LOW PRESSURE SYSTEM APPROACHES THE AREA. A
SLIGHT CHANCE OF THUNDERSTORMS EXISTS THURSDAY AS THIS STORM MOVES
ACROSS THE COASTAL WATERS. STRONGER NORTHWEST WINDS RETURN LATE IN
THE WEEK AND INTO THE WEEKEND AS HIGH PRESSURE REDEVELOPS OVER THE
REGION.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: BELL
AVIATION/MARINE: CW
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AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
551 PM MDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 543 PM MDT FRI MAY 15 2015
QUICK UPDATE TO BOOST POPS ACROSS MUCH OF THE FORECAST AREA FOR
THE NEXT SEVERAL HOURS. LATEST HRRR AND 18Z RUNS A LITTLE MORE
AGGRESSIVE OVERNIGHT AND WILL TREND POPS IN THIS DIRECTION. MINOR
WIGGLES OR WAVES IN THE FLOW WILL CONTINUE TO SPARK AREAS OF
SHOWERS WITH PERIODS OF NULL WEATHER ALSO EXPECTED THROUGH THE
OVERNIGHT HOURS.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 352 PM MDT FRI MAY 15 2015
THE LOW PRESSURE SYSTEM OVER THE GREAT BASIN WILL VERY GRADUALLY
SHIFT TO THE NORTHEAST TONIGHT AND CENTER ITS MAIN CORE OVER
NORTHERN UTAH AT 500MB BY THE EARLY MORNING HOURS...WITH A WEAK
CENTER OF CIRCULATION NEAR THE 4 CORNERS EMBEDDED IN THE GENERAL
PATTERN AT THIS SAME TIME. THIS SYSTEM IS BROADLY ORGANIZED AND
BECAUSE OF THAT...POCKETS OF NO SIGNIFICANT WEATHER AND POCKETS OF
MODERATE TO HEAVY PRECIPITATION WILL OCCUR. CURRENT SATELLITE
IMAGERY INDICATES AN AREA OF GOOD UPLIFT OVER THE PAGOSA
SPRINGS/WOLF CREEK REGION. NE UTAH AND NW COLORADO ARE
TRANSITIONING INTO A MORE STABLE AREA SO WILL SEE A BREAK FOR
ABOUT 6 TO 12 HOURS THIS EVENING WITH THE OCCASIONAL ISOLATED SHOWER
ABLE TO DEVELOP. COLD AIR IS ADVECTING INTO THE REGION WITH SNOW
LEVEL EXPECTED TO DROP THROUGHOUT THE EVENING. GOOD VERTICAL
VELOCITY FORECAST FOR THE FOUR CORNERS TONIGHT BETWEEN 5PM THIS
EVENING THROUGH TOMORROW MORNING SO WILL EXPECT PRECIPITATION TO
PICK UP THIS EVENING IN THIS AREA WITH EFFICIENT PRECIPITATION
RATES...AND SNOW DOWN TO 7500 FEET AND FALLING BY MIDNIGHT.
ANOMALOUSLY STRONG CLOSED LOW EJECTS NORTHEAST ACROSS THE WESTERN
SLOPE ON SATURDAY. THE COLDEST AIR AND DYNAMICAL LIFT OCCURS WITH
THIS FEATURE. THE BEST QPF WILL BE FOCUSED OVER THE SAN JUAN
MOUNTAINS...ALTHOUGH THE WRN CO MOUNTAINS WILL GET A FAIR AMOUNT
TONIGHT AND SATURDAY MORNING.
A SECONDARY SHORT WAVE ROTATES INTO WRN COLORADO SATURDAY NIGHT.
ALTHOUGH THIS SHORT WAVE ARRIVES FROM THE NORTHWEST...MODEL DATA
SHOWS BRIEF MID LEVEL COLD ADVECTION SATURDAY EVENING (BUT NOT ANY
COLDER THAN THE MAIN COLD CORE TONIGHT/SATURDAY). SNOW LEVELS
WILL NOT FALL ANY LOWER THAN OCCURS SATURDAY MORNING...POSSIBLY
BECOME SLIGHTER HIGHER GIVEN SLIGHTLY WARMER AIR AND LOWER QPF
RATES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 352 PM MDT FRI MAY 15 2015
SOME SHORT LIVED TERRAIN DRIVEN CONVECTIVE SHOWERS WILL OCCUR
SUNDAY AFTERNOON...OTHERWISE A BRIEF RESPITE FROM THE RAIN OR
SNOW. BUT THE NEXT PACIFIC CLOSED LOW BARRELS INTO CALIFORNIA ON
MONDAY. A NEGATIVELY TILTED SHORT WAVE EJECTS ACROSS THE FORECAST
AREA MONDAY NIGHT AND TUESDAY. LIKE THE CURRENT WEATHER
SYSTEM...THIS GENERATES ANOTHER HEALTHY DOSE OF SHOWERS/STORMS
WITH A FAIR AMOUNT OF RAINFALL. THIS WILL BE A WARMER SYSTEM AND
SNOW WILL BE LIMITED TO ABOVE TIMBERLINE...MAYBE SNOW LEVELS
LOWERING TO THE MOUNTAIN PASSES.
DRIER SOUTHWEST FLOW PREVAILS OVER THE FOUR CORNERS REGION FOR THE
WEDNESDAY THROUGH FRIDAY TIME FRAME. SOME DIURNAL CONVECTIVE
SHOWERS MAY STILL FORM OVER THE MOUNTAIN AREAS...BUT THESE WILL
NOT BE LONG LASTING AND PRODUCE LIGHT RAIN AMOUNTS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 449 PM MDT FRI MAY 15 2015
THIS VERY WET SYSTEM WILL CONTINUE TO IMPACT FLIGHT OPERATIONS
ACROSS EASTERN UTAH AND WESTERN COLORADO OVER THE NEXT 24 HOURS.
THREATS WILL BE LOWERED FLIGHT CRITERIA AND OCCASIONAL LIGHTNING
DURING THE AFTERNOON AND EVENING TIME PERIODS FROM PASSING
THUNDERSTORMS. MOST VALLEY LOCATIONS WILL BE ABLE TO SUSTAIN VFR
CONDITIONS BUT TEMPORARY MVFR WILL BE POSSIBLE IN PASSING SHOWERS.
AT THE MOUNTAIN TERMINALS SITES INCLUDING KASE...KTEX AND POSSIBLY
KEGE...IFR CONDITIONS WILL ALSO BE POSSIBLE WITH REDUCTION TO BOTH
VSBY AND CIGS COMING FROM SNOWFALL THROUGH 16/17Z.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ009-010-
012-018-019.
WINTER STORM WARNING UNTIL 9 AM MDT SUNDAY FOR COZ009-010-012-
018-019.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR
COZ017.
WINTER WEATHER ADVISORY UNTIL 9 AM MDT SUNDAY FOR COZ004-013.
UT...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR
UTZ028.
&&
$$
UPDATE...JDC
SHORT TERM...JAM/PF
LONG TERM...PF
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1004 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/...
10 PM UPDATE...SHOWERS CONTINUE ACROSS NEW YORK STATE. THEY DO
APPEAR TO BE REACHING THE GROUND BACK NEAR LAKE ONTARIO.
OTHERWISE...20 TO 30 DEGREE DEWPOINT DEPRESSIONS CONTINUE TO DRY
OUT SHOWERS. LATEST HIRES GUIDANCE SUGGESTS THIS WILL CONTINUE
THROUGH 06Z AT LEAST...IF NOT 09Z. NOT SURE IF THAT IS COMPLETELY
ACCURATE...SO MADE ONLY MINOR EDITS TO THE POPS FOR THIS UPDATE.
FORECAST IS GENERALLY ON TRACK.
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 SNOW COVER
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 /02Z 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/RLG/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...NOCERA
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1003 AM EDT THU MAY 14 2015
.SYNOPSIS...
LARGE HIGH PRESSURE WILL BUILD ACROSS THE EASTERN U.S. WITH DRIER
WEATHER THROUGH THE REMAINDER OF THIS WEEK. AN UPPER LEVEL
DISTURBANCE WILL BRING SHOWERS TO THE REGION FRIDAY NIGHT AND
SATURDAY. A BACK DOOR COLD FRONT USHERS IN COOLER AIR SUNDAY
THROUGH THE BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...
MINOR CHANGES TO THE FORECAST. WENT WITH A HRRR / RAP BLEND FOR
THE NEXT 12-HOURS WITH RESPECT TO TEMPERATURES / DEWPOINTS / WIND
THAT NETS HIGHS AROUND THE UPPER-60S TO LOW-70S WITH MINIMUM
RELATIVE HUMIDITY VALUES DOWN AROUND 20-PERCENT. HIGH PRESSURE IN
CONTROL RESULTING IN LIGHT WINDS WHICH WILL ALLOW SEABREEZES TO
COME ASHORE BY MIDDAY...PUSHING INTO THE EASTERN- INTERIOR BY
EVENING. WINDS OVERALL REMAINING LIGHT...EXPECTING THE STRONGEST
ALONG THE COASTS WITH ONSHORE FLOW...GUSTS AROUND 15 MPH POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT...
ANOTHER GOOD RADIATIONAL COOLING NIGHT WITH LIGHT WINDS AND CLEAR
SKIES AS HIGH PRES REMAINS IN CONTROL. MINS WILL LIKELY DROP INTO
THE MID/UPPER 30S WITH PATCHY FROST IN THE NORMALLY COLDER
LOCATIONS IN W MA AND INTERIOR E MA AND FROST ADVISORIES MAY BE
NEEDED AGAIN. ELSEWHERE LOWS WILL BE MOSTLY IN THE 40S.
FRIDAY...
HIGH PRES WILL BE S OF NEW ENG WITH DEVELOPING SW FLOW BRINGING
MILDER AIR TO SNE. 850 MB TEMPS WARMING TO 7-8C WHICH TRANSLATES
TO HIGHS IN THE LOW TO MID 70S...BUT COOLER ALONG THE COAST WHERE
SEABREEZES LIKELY AGAIN. SUNSHINE WILL GIVE WAY TO INCREASING HIGH
CLOUDS IN THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* RAIN LATE FRI INTO THE WEEKEND WITH SHORTWAVE
* BACK DOOR COLD FRONT WILL BRING COOLER TEMPERATURES SUN AND MON
* COLD FRONT MAY BRING ANOTHER ROUND OF SHOWERS TOWARDS MIDWEEK
MODELS ARE IN DECENT AGREEMENT THROUGH THE LONG TERM PERIOD. AS WE
MOVE INTO THE WEEKEND SHORTWAVE WILL MOVE THROUGH SOUTHERN NEW
ENGLAND BRINGING RAIN SHOWERS TO THE REGION. AN UPPER LEVEL RIDGE
THEN BUILDS OVER THE REGION AND A BACK DOOR COLD FRONT WILL MOVE
INTO SOUTHERN NEW ENGLAND SUNDAY. THE EXACT TIMING AND
SOUTHWESTWARD EXTENT OF THE FRONT IS IN QUESTION WITH THE ECMWF
BRINGING IT MUCH FARTHER SOUTHWEST THAN THE GFS. THIS WILL MAKE A
BIG DIFFERENCE IN HIGH TEMPERATURES. BEYOND THE BACK DOOR COLD
FRONT...THERE ARE TIMING DISCREPANCIES AMONGST THE MODELS.
FRIDAY NIGHT AND SATURDAY...THIS PERIOD LOOKS TO HAVE SOME RAIN
SHOWERS AS A SHORTWAVE DISTURBANCE MOVES OVER SOUTHERN NEW ENGLAND.
THERE IS SOME MODEST INSTABILITY DURING THIS TIME FRAME AS INDICATED
BY K INDICES ABOVE 30 AND NEGATIVE SHOWALTER INDICES. THIS COULD
RESULT IN SOME ISOLATED THUNDER WITH THESE SHOWERS.
SUNDAY...A BACK DOOR COLD FRONT WILL PUSH INTO SOUTHERN NEW
ENGLAND...BRINGING AN END TO THE RAIN SHOWERS. AS MENTIONED
ABOVE...THE WESTWARD EXTENT OF THIS FRONT DEPENDS ON THE MODEL
MAKING TEMPERATURE FORECASTS DIFFICULT. EXPECT SUNDAY TO BE A DRY
DAY WITH CHILLY NORTHEAST WINDS ALONG THE EAST COAST AND
PARTICULARLY ACROSS NORTHEASTERN MASSACHUSETTS. TEMPERATURE
FORECAST IS LOW CONFIDENCE...PARTICULARLY ACROSS EASTERN MASS AND
RHODE ISLAND.
MONDAY THROUGH WEDNESDAY...THERE ARE TIMING DISCREPANCIES AMONGST
THE MODELS BUT THE OVERALL PATTERN IS SIMILAR BETWEEN THE SOLUTIONS.
THE UPPER RIDGE OVER NEW ENGLAND WILL WEAKEN AND GRADUALLY MOVE
OFFSHORE LATE MONDAY INTO TUESDAY. THEN LOW PRESSURE MOVING THROUGH
QUEBEC WILL BRING A COLD FRONT THROUGH SOUTHERN NEW ENGLAND
TUESDAY OR WEDNESDAY ALLOWING FOR ANOTHER CHANCE OF SHOWERS.
TEMPERATURES WILL BE RIGHT AROUND NORMAL DURING THIS TIME FRAME.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
THROUGH FRIDAY...VFR. ONSHORE SEABREEZES DEVELOPING AROUND 15Z.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE. MAINLY VFR.
PERIODS OF MVFR/IFR IN SCATTERED SHOWERS AND FOG.
SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR
CONDITIONS BEHIND BACK DOOR COLD FRONT.
MONDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
TODAY THROUGH FRIDAY...HIGH PRES WILL BRING QUIET BOATING
WEATHER WITH LIGHT WINDS AND SEAS AND GOOD VSBYS. WINDS WILL
BECOME ONSHORE 10-15 KTS OVER NEARSHORE WATERS TODAY AND AGAIN FRI
AS SEABREEZES DEVELOP.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT AND SATURDAY...LOW CONFIDENCE. WHILE CONDITIONS ARE
CURRENTLY EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA...WINDS AND
SEAS WILL BE INCREASING AS A COLD FRONT APPROACHES THE WATERS. 5
FOOT SEAS IN PARTICULAR ARE NOT OUT OF THE QUESTION FOR THE OUTER
WATERS.
SUNDAY AND MONDAY...MAINLY QUIET BOATING WEATHER AS HIGH PRESSURE
BUILDS SOUTH OVER THE WATERS. NORTHEASTERLY WINDS SUNDAY WILL
GRADUALLY BECOME LIGHT AND VARIABLE.
&&
.FIRE WEATHER...
TODAY AND FRIDAY...DRY WEATHER CONDITIONS WILL CONTINUE WITH
MINIMUM RH VALUES AWAY FROM THE IMMEDIATE COAST DROPPING TO UPPER
TEENS TO 20S TODAY AND 20-30 PERCENT FRIDAY. SINCE HIGH PRESSURE
WILL BE OVERHEAD...WINDS WILL BE LIGHT WITH SPEEDS LESS THAN 15
MPH.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FROST ADVISORY FROM 2 AM TO 7 AM EDT FRIDAY FOR MAZ002-003-008-
010.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/RLG
NEAR TERM...KJC/RLG/SIPPRELL
SHORT TERM...KJC
LONG TERM...RLG
AVIATION...KJC/RLG
MARINE...KJC/RLG
FIRE WEATHER...WFO BOX STAFF
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
1002 AM EDT THU MAY 14 2015
.UPDATE...
ANOTHER WARM AND MUGGY DAY EXPECTED ACROSS WEST-CENTRAL AND
SOUTHWEST FLORIDA. EARLY MORNING VISIBLE SATELLITE IMAGERY SHOWS
MOSTLY CLEAR SKIES THIS MORNING WITH ONLY A FEW HIGH CLOUDS PRESENT
ACROSS THE AREA. WITH MOSTLY CLEAR SKIES...TEMPS WILL WARM
QUICKLY INTO THE MIDDLE/UPPER 80S BEFORE ULTIMATELY TOPPING OUT
IN THE LOWER 90S FOR MUCH OF THE AREA...SLIGHTLY COOLER ALONG THE
IMMEDIATE COAST.
AS FAR AS RAIN CHANCES ARE CONCERNED...THE OVERALL SETUP FOR TODAY
LOOKS SIMILAR TO YESTERDAY. WITH DECENT SE/E FLOW IN PLACE IN THE
LOWER LEVELS WEST COAST SEA BREEZE WILL LIKELY HAVE A DIFFICULT TIME
PENETRATING TOO FAR INLAND TODAY. LOCAL HI-RES MODELS SUPPORT THIS
THINKING OF A LIKELY SEA BREEZE COLLISION NEAR THE I-75 CORRIDOR.
MOST RECENT HRRR RUN IS NOT VERY ROBUST WITH OVERALL PRECIP COVERAGE
NOR ARE RECENT RUNS OF CONVECTION ALLOWING MODELS SO MAINTAINING
POPS IN THE 30 TO 50 RANGE FOR THE AREA...HIGHEST NEAR AND WEST
OF I-75...SEEMS REASONABLE. ONLY MADE A FEW MINOR ADJUSTMENTS FOR
THE MORNING UPDATE.
&&
.AVIATION...
VFR CONDITIONS EXPECTED TO PREVAIL THIS MORNING AND INTO THE
AFTERNOON. EASTERLY FLOW THROUGH THE MORNING HOURS WILL GIVE WAY
TO AN AFTERNOON WEST COAST SEA BREEZE FOR COASTAL TERMINALS. VCTS
DEVELOPING DURING THE LATE AFTERNOON HOURS WILL AFFECT TAFS SITES
INTO THE EVENING BEFORE STORM COVERAGE DISSIPATES AFTER SUNSET.
LOCALIZED MVFR/IFR RESTRICTIONS WILL BE POSSIBLE WITH ANY
THUNDERSTORMS BUT WILL NOT INCLUDE ANY TEMPOS AT THIS TIME.
&&
.MARINE...
SURFACE RIDGING CENTERED WELL NORTH OF THE AREA WILL HELP MAINTAIN
GENERALLY EASTERLY FLOW. EXPECT A SEA BREEZE CIRCULATION TO DEVELOP
EACH AFTERNOON NEAR THE COAST WITH A NOCTURNAL EASTERLY SURGE
THROUGH THE WEEKEND. SCATTERED SHOWERS AND STORMS NEAR THE COAST ARE
EXPECTED TO SHIFT INTO THE NEAR AND OFF SHORE WATERS DURING THE LATE
EVENING HOURS AS THE LAND BREEZE DEVELOPS. NO CHANGES NEEDED FOR THE
MORNING UPDATE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 73 89 72 / 50 40 50 50
FMY 91 71 91 71 / 40 20 40 30
GIF 91 71 90 71 / 40 10 50 10
SRQ 89 71 88 71 / 50 40 50 50
BKV 91 70 88 69 / 50 20 50 20
SPG 90 75 89 75 / 40 40 50 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION/FIRE WEATHER/MARINE...11/MCKAUGHAN
DECISION SUPPORT...14/MROCZKA
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
555 AM EDT THU MAY 14 2015
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH TONIGHT. THE
HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA NEXT TUESDAY OR
WEDNESDAY. HIGH PRESSURE WILL THEN RETURN BY THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FOG HAS BECOME A BIT MORE WIDESPREAD THAN EARLIER ANTICIPATED.
WEBCAMS...SURFACE OBSERVATIONS AND MEDIA REPORTS INDICATE THE FOG
IS LOCALLY DENSE AT TIMES WITH VISIBILITIES 1/4 MI OR LESS. GOES
FOG PRODUCTS SUGGESTS THE DENSE FOG MAY BE A BIT MORE WIDESPREAD
ACROSS PARTS OF SCREVEN...JENKINS AND BULLOCH COUNTIES. A DENSE
FOG ADVISORY MAY BE NEEDED FOR SOME COUNTIES IF THE DENSE FOG
CONTINUES TO EXPAND IN AREA.
TODAY...DEEP LAYERED HIGH PRESSURE WILL REMAIN IN TACT ACROSS THE
SOUTHEAST U.S. TODAY. HIGH RESOLUTION MODELS SUGGEST A NORTHEAST
WIND SURGE WORKING STEADILY DOWN THE NORTH CAROLINA COAST COULD
PROVIDE ENOUGH LOW-LEVEL CONVERGENCE TO SPREAD SOME ISOLATED
MARINE-BASED SHOWER ACTIVITY INLAND ACROSS PART OF UPPER
CHARLESTON AND EASTERN BERKELEY COUNTIES LATER THIS MORNING.
CONFIDENCE IS QUITE LOW IN THIS SCENARIO GIVEN HOW DRY THE LOWER
TROPOSPHERE IS ABOVE THE BOUNDARY LAYER SO WILL CARRY SOME VERY
LOW NON-ZERO POPS IN THIS AREA...BUT GENERALLY EXPECT DRY
CONDITIONS TO PREVAIL.
LOW-LEVEL MOISTURE RETURN WILL BEGIN TO SNEAK INTO THE FAR
SOUTHERN AND SOUTHWESTERN ZONES THIS AFTERNOON AS SURFACE HIGH
PRESSURE MOVES OFF THE MID-ATLANTIC COAST. FORECAST SOUNDINGS DO
NOT REALLY SUPPORT MUCH IN THE WAY OF MEANINGFUL INSTABILITY IN
THESE AREAS DESPITE THE SLOW EROSION OF THE CAPPING INVERSION.
WITH LITTLE/NO LOW-LEVEL CONVERGENCE EXPECTED ALONG THE PURE
/VERSUS RESULTANT/ SEA BREEZE CIRCULATION...POPS WILL BE KEPT
BELOW MENTIONABLE THRESHOLDS FOR NOW.
HIGHS WILL RANGE FROM THE LOWER 80S NORTH TO THE MID 80S CENTRAL
AND SOUTH...WARMEST ACROSS FAR INTERIOR SOUTHEAST GEORGIA. MID TO
UPPER 70S ARE LIKELY AT THE BEACHES WITH BREEZY ONSHORE WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...LOW-LEVEL MOISTURE RETURN WILL CONTINUE THROUGH THE
NIGHT AS HIGH PRESSURE SHIFTS FARTHER OFFSHORE INTO THE WESTERN
ATLANTIC. MEAN MID-UPPER LEVEL RIDGING STILL LOOKS STRONG ENOUGH
TO PRECLUDE SHOWER ACTIVITY OVERNIGHT...BUT A BRIEF SPRINKLE OR
SHOWER CAN NOT BE COMPLETELY RULED OUT ACROSS SOUTHEAST GEORGIA
OVERNIGHT...MAINLY SOUTH OF THE I-16 CORRIDOR. WILL CONTINUE TO
HIGHLIGHT A DRY FORECAST FOR NOW GIVEN LOW CONFIDENCE IN ANY
MEASURABLE SHOWER ACTIVITY DEVELOPING. CLOUDS WILL THICKEN THROUGH
THE NIGHT WITH LOWS RANGING FROM THE LOWER 60S FAR NORTH TO THE
MID 60S ELSEWHERE.
SFC HIGH PRESSURE WILL BECOME CENTERED OVER THE WESTERN ATLANTIC BY
THE WEEKEND...SETTING UP EAST/SOUTHEAST FLOW THAT SLOWLY DEEPENS
MOISTURE OVER THE AREA AHEAD OF A SERIES OF SUBTLE H5 SHORTWAVES
THAT ROUND THE NORTHWEST FRINGE OF A MID LVL RIDGE CENTERED TO OUR
SOUTH. A SLIGHT CHANCE OF DIURNAL SHOWERS AND/OR THUNDERSTORMS WILL
BE POSSIBLE OVER INLAND PORTIONS OF SOUTHEAST GEORGIA ON FRIDAY AND
SATURDAY...FOLLOWED BY CHANCES OF AFTERNOON SHOWERS AND
THUNDERSTORMS ON SUNDAY...MAINLY AWAY FROM THE COAST WHERE LOW LVL
MOISTURE IS HIGHEST AND A SEABREEZE PROGRESSES INLAND. TEMPS SHOULD
BE A FEW DEGREES COOLER ON FRIDAY...IN THE UPPER 70S TO LOWER
80S...BUT A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE
WEEKEND. IN GENERAL...HIGH TEMPS SHOULD RANGE IN THE LOW TO MID 80S
ON SATURDAY...THEN MID TO UPPER 80S ON SUNDAY...WARMEST AWAY FROM
THE COAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH
PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM
THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT
IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO
RETURN TO THE AREA WHILE WEAK H5 SHORTWAVES CONTINUE TO ROUND
NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF SHOWERS
AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING INTO
EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A COLD FRONT WILL
THEN APPROACH FROM THE NORTH/NORTHWEST ON TUESDAY BEFORE PUSHING
THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. HIGHER COVERAGE OF
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITH COLD FROPA. HIGH
PRESSURE SHOULD THEN BUILD INTO THE AREA FROM THE NORTH/NORTHWEST
INTO THURSDAY.
TEMPS WILL BE ON A WARMING TREND NEXT WEEK...WITH MAX TEMPS REACHING
THE UPPER 80S TO LOWER 90S ON TUESDAY AHEAD OF THE APPROACHING COLD
FRONT. TEMPS SHOULD BE A FEW DEGREES COOLER ON WEDNESDAY AS HIGH
PRESSURE BUILDS BEHIND THE FRONT THROUGH THURSDAY. OVERNIGHT LOWS
SHOULD RANGE IN THE MID TO UPPER 60S AWAY FROM THE COAST.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON
LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY
ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY
NEXT WEEK.
&&
.MARINE...
TODAY...A NORTHEAST WIND SURGE WILL OVERSPREAD THE WATERS TODAY
WITH DIRECTIONS SLOWLY VEERING TO THE EAST. WINDS LOOK TO GO NO
HIGHER THAN 15-20 KT FOR ALL LEGS WITH GUSTS HOLDING BELOW 25 KT.
SEAS WILL BUILD IN THE NORTHEAST FETCH...REACHING 3-5 FT NEARSHORE
WATERS AND A SOLID 5 FT FOR THE GEORGIA OFFSHORE WATERS BY LATE
THIS AFTERNOON. ATTM BOTH WINDS AND SEAS LOOK TO REMAIN BELOW
SMALL CRAFT ADVISORY LEVELS.
TONIGHT...MODEST ONSHORE WINDS WILL PERSIST...ALTHOUGH SPEEDS WILL
DIMINISH SOMEWHAT. WINDS ARE EXPECTED TO DROP TO 10-15 KT
NEARSHORE WATERS...BUT REMAIN 15-20 KT FOR THE GEORGIA OFFSHORE
WATERS. SEAS WILL BUILD A BIT MORE...PEAKING 3-5 FT NEARSHORE
WATERS WITH 4-6 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE
ISSUED FOR THE GEORGIA OFFSHORE LEG...BEGINNING AT 6 PM THIS
EVENING AND REMAINING IN FORCE THROUGH THE NIGHT.
FRIDAY THROUGH MONDAY...MARGINAL SMALL CRAFT ADVISORY CONDITIONS
SHOULD LINGER IN OFFSHORE GEORGIA WATERS INTO EARLY FRIDAY...BEFORE
HIGH PRESSURE BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. WINDS
WILL THEN IMPROVE THROUGH THE WEEKEND AS THE PRESSURE GRADIENT
WEAKENS OVER THE COASTAL WATERS. SEAS WILL ALSO SUBSIDE THROUGH THE
WEEKEND...RANGING NO HIGHER THAN 2-4 FT. HIGHEST SEAS ARE EXPECTED
IN OFFSHORE GEORGIA WATERS.
&&
.TIDES/COASTAL FLOODING...
ONSHORE WINDS COMBINED WITH LUNAR INFLUENCES WILL HELP PUSH TIDE
LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL TIDES THROUGH LATE
WEEK...POSSIBLY CAUSING SHALLOW COASTAL FLOODING LATER IN THE WEEK
DURING THE EVENING HIGH TIDES...MAINLY ALONG THE SOUTH CAROLINA
COAST SATURDAY AND SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 11 AM EDT
FRIDAY FOR AMZ374.
&&
$$
ST/DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
409 AM EDT THU MAY 14 2015
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH TONIGHT. THE
HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA NEXT TUESDAY OR
WEDNESDAY. HIGH PRESSURE WILL THEN RETURN BY THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
THROUGH SUNRISE...SOME VERY SHALLOW GROUND FOG HAS DEVELOPED
ALONG PORTIONS OF THE GEORGIA COAST THIS MORNING. WEBCAMS AND
SURFACE OBSERVATIONS INDICATE THE FOG IS QUITE SHALLOW IN NATURE
AND SHOULD NOT SIGNIFICANTLY IMPACT TRAVEL THIS MORNING. THE FOG
COULD EXPAND NORTH ALONG THE LOWER SOUTH CAROLINA THROUGH SUNRISE.
TODAY...DEEP LAYERED HIGH PRESSURE WILL REMAIN IN TACT ACROSS THE
SOUTHEAST U.S. TODAY. HIGH RESOLUTION MODELS SUGGEST A NORTHEAST
WIND SURGE WORKING STEADILY DOWN THE NORTH CAROLINA COAST COULD
PROVIDE ENOUGH LOW-LEVEL CONVERGENCE TO SPREAD SOME ISOLATED
MARINE-BASED SHOWER ACTIVITY INLAND ACROSS PART OF UPPER
CHARLESTON AND EASTERN BERKELEY COUNTIES LATER THIS MORNING.
CONFIDENCE IS QUITE LOW IN THIS SCENARIO GIVEN HOW DRY THE LOWER
TROPOSPHERE IS ABOVE THE BOUNDARY LAYER SO WILL CARRY SOME VERY
LOW NON-ZERO POPS IN THIS AREA...BUT GENERALLY EXPECT DRY
CONDITIONS TO PREVAIL.
LOW-LEVEL MOISTURE RETURN WILL BEGIN TO SNEAK INTO THE FAR
SOUTHERN AND SOUTHWESTERN ZONES THIS AFTERNOON AS SURFACE HIGH
PRESSURE MOVES OFF THE MID-ATLANTIC COAST. FORECAST SOUNDINGS DO
NOT REALLY SUPPORT MUCH IN THE WAY OF MEANINGFUL INSTABILITY IN
THESE AREAS DESPITE THE SLOW EROSION OF THE CAPPING INVERSION.
WITH LITTLE/NO LOW-LEVEL CONVERGENCE EXPECTED ALONG THE PURE
/VERSUS RESULTANT/ SEA BREEZE CIRCULATION...POPS WILL BE KEPT
BELOW MENTIONABLE THRESHOLDS FOR NOW.
HIGHS WILL RANGE FROM THE LOWER 80S NORTH TO THE MID 80S CENTRAL
AND SOUTH...WARMEST ACROSS FAR INTERIOR SOUTHEAST GEORGIA. MID TO
UPPER 70S ARE LIKELY AT THE BEACHES WITH BREEZY ONSHORE WINDS.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
TONIGHT...LOW-LEVEL MOISTURE RETURN WILL CONTINUE THROUGH THE
NIGHT AS HIGH PRESSURE SHIFTS FARTHER OFFSHORE INTO THE WESTERN
ATLANTIC. MEAN MID-UPPER LEVEL RIDGING STILL LOOKS STRONG ENOUGH
TO PRECLUDE SHOWER ACTIVITY OVERNIGHT...BUT A BRIEF SPRINKLE OR
SHOWER CAN NOT BE COMPLETELY RULED OUT ACROSS SOUTHEAST GEORGIA
OVERNIGHT...MAINLY SOUTH OF THE I-16 CORRIDOR. WILL CONTINUE TO
HIGHLIGHT A DRY FORECAST FOR NOW GIVEN LOW CONFIDENCE IN ANY
MEASURABLE SHOWER ACTIVITY DEVELOPING. CLOUDS WILL THICKEN THROUGH
THE NIGHT WITH LOWS RANGING FROM THE LOWER 60S FAR NORTH TO THE
MID 60S ELSEWHERE.
SFC HIGH PRESSURE WILL BECOME CENTERED OVER THE WESTERN ATLANTIC BY
THE WEEKEND...SETTING UP EAST/SOUTHEAST FLOW THAT SLOWLY DEEPENS
MOISTURE OVER THE AREA AHEAD OF A SERIES OF SUBTLE H5 SHORTWAVES
THAT ROUND THE NORTHWEST FRINGE OF A MID LVL RIDGE CENTERED TO OUR
SOUTH. A SLIGHT CHANCE OF DIURNAL SHOWERS AND/OR THUNDERSTORMS WILL
BE POSSIBLE OVER INLAND PORTIONS OF SOUTHEAST GEORGIA ON FRIDAY AND
SATURDAY...FOLLOWED BY CHANCES OF AFTERNOON SHOWERS AND
THUNDERSTORMS ON SUNDAY...MAINLY AWAY FROM THE COAST WHERE LOW LVL
MOISTURE IS HIGHEST AND A SEABREEZE PROGRESSES INLAND. TEMPS SHOULD
BE A FEW DEGREES COOLER ON FRIDAY...IN THE UPPER 70S TO LOWER
80S...BUT A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE
WEEKEND. IN GENERAL...HIGH TEMPS SHOULD RANGE IN THE LOW TO MID 80S
ON SATURDAY...THEN MID TO UPPER 80S ON SUNDAY...WARMEST AWAY FROM
THE COAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH
PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM
THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT
IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO
RETURN TO THE AREA WHILE WEAK H5 SHORTWAVES CONTINUE TO ROUND
NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF SHOWERS
AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING INTO
EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A COLD FRONT WILL
THEN APPROACH FROM THE NORTH/NORTHWEST ON TUESDAY BEFORE PUSHING
THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. HIGHER COVERAGE OF
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITH COLD FROPA. HIGH
PRESSURE SHOULD THEN BUILD INTO THE AREA FROM THE NORTH/NORTHWEST
INTO THURSDAY.
TEMPS WILL BE ON A WARMING TREND NEXT WEEK...WITH MAX TEMPS REACHING
THE UPPER 80S TO LOWER 90S ON TUESDAY AHEAD OF THE APPROACHING COLD
FRONT. TEMPS SHOULD BE A FEW DEGREES COOLER ON WEDNESDAY AS HIGH
PRESSURE BUILDS BEHIND THE FRONT THROUGH THURSDAY. OVERNIGHT LOWS
SHOULD RANGE IN THE MID TO UPPER 60S AWAY FROM THE COAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON
LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY
ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY
NEXT WEEK.
&&
.MARINE...
TODAY...A NORTHEAST WIND SURGE WILL OVERSPREAD THE WATERS TODAY
WITH DIRECTIONS SLOWLY VEERING TO THE EAST. WINDS LOOK TO GO NO
HIGHER THAN 15-20 KT FOR ALL LEGS WITH GUSTS HOLDING BELOW 25 KT.
SEAS WILL BUILD IN THE NORTHEAST FETCH...REACHING 3-5 FT NEARSHORE
WATERS AND A SOLID 5 FT FOR THE GEORGIA OFFSHORE WATERS BY LATE
THIS AFTERNOON. ATTM BOTH WINDS AND SEAS LOOK TO REMAIN BELOW
SMALL CRAFT ADVISORY LEVELS.
TONIGHT...MODEST ONSHORE WINDS WILL PERSIST...ALTHOUGH SPEEDS WILL
DIMINISH SOMEWHAT. WINDS ARE EXPECTED TO DROP TO 10-15 KT
NEARSHORE WATERS...BUT REMAIN 15-20 KT FOR THE GEORGIA OFFSHORE
WATERS. SEAS WILL BUILD A BIT MORE...PEAKING 3-5 FT NEARSHORE
WATERS WITH 4-6 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE
ISSUED FOR THE GEORGIA OFFSHORE LEG...BEGINNING AT 6 PM THIS
EVENING AND REMAINING IN FORCE THROUGH THE NIGHT.
FRIDAY THROUGH MONDAY...MARGINAL SMALL CRAFT ADVISORY CONDITIONS
SHOULD LINGER IN OFFSHORE GEORGIA WATERS INTO EARLY FRIDAY...BEFORE
HIGH PRESSURE BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. WINDS
WILL THEN IMPROVE THROUGH THE WEEKEND AS THE PRESSURE GRADIENT
WEAKENS OVER THE COASTAL WATERS. SEAS WILL ALSO SUBSIDE THROUGH THE
WEEKEND...RANGING NO HIGHER THAN 2-4 FT. HIGHEST SEAS ARE EXPECTED
IN OFFSHORE GEORGIA WATERS.
&&
.TIDES/COASTAL FLOODING...
ONSHORE WINDS COMBINED WITH LUNAR INFLUENCES WILL HELP PUSH TIDE
LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL TIDES THROUGH LATE
WEEK...POSSIBLY CAUSING SHALLOW COASTAL FLOODING LATER IN THE WEEK
DURING THE EVENING HIGH TIDES...MAINLY ALONG THE SOUTH CAROLINA
COAST SATURDAY AND SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 11 AM EDT
FRIDAY FOR AMZ374.
&&
$$
ST/DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
130 AM EDT THU MAY 14 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD FROM THE NORTH OVERNIGHT INTO LATE WEEK.
THE HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY
NEXT WEEK. A WEAK COLD FRONT COULD PUSH THROUGH THE AREA NEXT TUESDAY
OR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MINOR ADJUSTMENTS FOR CURRENT TRENDS. NOT TOO KEAN ON FOG OR
STRATUS DEVELOPMENT GIVEN LATEST HIGH RESOLUTION DATA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
MODELS IN GOOD AGREEMENT THAT HIGH PRESSURE RIDGING WILL PREVAIL
THIS PERIOD ALONG WITH LIMITED MOISTURE KEEPING RAIN CHANCES BELOW
NORMAL. HOWEVER...THAT DOES NOT MEAN IT WILL BE DRY EVERYWHERE THE
ENTIRE TIME...ESPECIALLY CLOSER TO THE ALTAMAHA RIVER WHERE THE BEST
MOISTURE AND INSTABILITY ARE EXPECTED. TEMPERATURES SHOULD BE NEAR
TO SLIGHTLY BELOW NORMAL...WITH THE WARMEST TEMPS ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH
PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM
THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT
IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO
RETURN TO THE AREA WHILE NUMEROUS H5 SHORTWAVES ROUND THE
NORTH/NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF
SHOWERS AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING
INTO EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A WEAK COLD
FRONT COULD THEN APPROACH THE AREA FROM THE NORTH/NORTHWEST TUESDAY
AND/OR WEDNESDAY...LEADING TO HIGHER COVERAGE OF SHOWERS AND
THUNDERSTORMS OVER THE AREA. TEMPS WILL BE ON A WARMING TREND NEXT
WEEK...WITH MAX TEMPS REACHING THE UPPER 80S TO AROUND 90 AWAY FROM
THE COAST. TEMPS COULD BE A FEW DEGREES COOLER ON WEDNESDAY SHOULD
COLD FROPA OCCUR. OVERNIGHT LOWS SHOULD RANGE IN THE MID TO UPPER
60S AWAY FROM THE COAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON
LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY
ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY
NEXT WEEK.
&&
.MARINE...
OVERNIGHT...A WEAK PRESSURE GRADIENT AND ONSHORE WINDS LESS THAN
15 KT WILL GIVE WAY TO HIGH PRESSURE BUILDING FROM THE
NORTH...TIGHTENING THE GRADIENT AND SUPPORTING A MODEST SURGE OF
NE WINDS AS HIGH AS 15-20 KT ACROSS SC WATERS LATE. EARLY SEAS OF
1-3 FT WILL BUILD TO 2-4 FT LATE...HIGHEST BEYOND 20 NM.
THURSDAY THROUGH SUNDAY...HIGH PRESSURE TO THE NORTH WILL SLOWLY
SHIFT OFFSHORE INTO THE ATLANTIC AND PERSIST THERE THROUGH THE
WEEKEND. THIS PATTERN WILL RESULT IN WINDS/SEAS THAT MOSTLY REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS. HOWEVER...WHILE THE HIGH IS CLOSE
TO THE AREA THURSDAY...A TIGHT PRESSURE GRADIENT WILL EXIST OVER THE
AREA AND WE CANNOT RULE OUT SOME 25 KT GUSTS OVER THE NEAR SHORE
WATERS AND 6 FT SEAS BEYOND 20 NM INTO THURSDAY NIGHT.
&&
.TIDES/COASTAL FLOODING...
ONSHORE WINDS WILL HELP PUSH TIDE LEVELS HIGHER THAN THE NORMAL
ASTRONOMICAL TIDES THROUGH LATE WEEK...POSSIBLY CAUSING SHALLOW
COASTAL/SALT WATER FLOODING LATER IN THE WEEK DURING THE EVENING
HIGH TIDES...MAINLY ALONG THE SC COAST.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS LINCOLN IL
913 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 906 PM CDT FRI MAY 15 2015
PLENTY OF WARM AIR ADVECTING INTO THE REGION AND WIDESPREAD
MID/HIGH LEVEL CLOUDS IN ADDITION TO REMAINING LOW WILL KEEP THE
TEMPS UP OVERNIGHT FOR CENTRAL ILLINOIS. ALTHOUGH LLVL RH HAS BEEN
ENHANCED BY THE EVENINGS RAINFALL...WIDESPREAD FOG NOT LIKELY AS
THE WINDS AND TEMPS STAY UP OVERNIGHT. WILL HAVE TO WATCH FOR SOME
PATCHY VIS REDUCTIONS, BUT NOT ENOUGH CONFIDENCE TO PUT IT IN THE
ZONES JUST YET. UPDATES FOR THE BREAK IN THE PRECIP...BRINGING
BACK CHANCE POPS IN THE VERY EARLY HOURS OF THE MORNING AS MODELS
STILL SPLIT OVER HOW TO HANDLE A POTENTIAL ROUND TWO.
&&
.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
MORNING UPPER AIR AND MOISTURE CHANNEL IMAGERY SHOWS CLOSED UPPER
LOW IN ROCKIES WITH A MAIN VORT LOBE IN THE CENTRAL PLAINS,
ADVECTING 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 LOCALIZED 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 ROCKIES,
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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 652 PM CDT FRI MAY 15 2015
ACTIVE WEATHER AS A ROUND OF STORMS MOVED THROUGH THIS EVENING.
SCATTERED THUNDERSTORMS WITH SIGNIFICANT OUTFLOW RESULTING IN HIGH
GUSTS. EXPECTING RAIN AND VCSH IN THE SHORTER TERM WITH SOME GUSTS
STILL POSSIBLE. MODELS VERY INCONSISTENT WITH THE DEVELOPMENT OF A
SECOND ROUND LATER THIS EVENING AS WELL AS THE THREAT FOR A
REDUCTION IN VIS. EXPECT AN UPDATE SHORTLY TO START TREND FOR THE
VIS DROP AS DWPTS STILL CLOSE TO OVERNIGHT LOWS AND DRIER AIR NOT
IMMINENT. CONFIDENCE LOW, BUT WITH INCREASED BOUNDARY LAYER RH
FROM VERY PROFICIENT STORMS THIS EVENING, CANNOT RULE IT OUT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...GEELHART
LONG TERM...GOETSCH
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
659 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
MORNING UPPER AIR AND MOISTURE CHANNEL IMAGERY SHOWS CLOSED UPPER
LOW IN ROCKIES WITH A MAIN VORT LOBE IN THE CENTRAL PLAINS,
ADVECTING 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 LOCALIZED 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 ROCKIES,
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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 652 PM CDT FRI MAY 15 2015
ACTIVE WEATHER AS A ROUND OF STORMS MOVED THROUGH THIS EVENING.
SCATTERED THUNDERSTORMS WITH SIGNIFICANT OUTFLOW RESULTING IN HIGH
GUSTS. EXPECTING RAIN AND VCSH IN THE SHORTER TERM WITH SOME GUSTS
STILL POSSIBLE. MODELS VERY INCONSISTENT WITH THE DEVELOPMENT OF A
SECOND ROUND LATER THIS EVENING AS WELL AS THE THREAT FOR A
REDUCTION IN VIS. EXPECT AN UPDATE SHORTLY TO START TREND FOR THE
VIS DROP AS DWPTS STILL CLOSE TO OVERNIGHT LOWS AND DRIER AIR NOT
IMMINENT. CONFIDENCE LOW, BUT WITH INCREASED BOUNDARY LAYER RH
FROM VERY PROFICIENT STORMS THIS EVENING, CANNOT RULE IT OUT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...GOETSCH
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
207 PM CDT THU MAY 14 2015
.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 SURPASE 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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM CDT THU MAY 14 2015
INITIAL BATCH OF SHOWERS HAS BEEN ERODING IN THE DRY AIR OVER
CENTRAL ILLINOIS...BUT STEADIER SHOWERS ARE MOVING NORTHEAST
THROUGH MISSOURI AND SHOULD AFFECT KPIA/KSPI TOWARD MID AFTERNOON.
HAVE NOT MADE MUCH CHANGE TO THE CURRENT TAF SET THROUGH ABOUT
09Z...AS SCATTERED RAIN WILL CONTINUE TO DEVELOP THIS EVENING.
HAVE REMOVED THUNDER MENTION AT KDEC/KCMI AS THE BETTER
INSTABILITY SHOULD BE FURTHER TO THE WEST. STILL HAVE SOME
CONCERNS WITH LLWS POTENTIAL IN THE 03-09Z TIME RANGE...BUT ENOUGH
QUESTIONS REMAIN ON CONVECTIVE POTENTIAL TO HOLD OFF MENTION.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...BARKER
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1237 PM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 952 AM CDT THU MAY 14 2015
SHOWERS IN WEST CENTRAL ILLINOIS HAVE BEEN STRUGGLING TO MAKE ANY
EASTWARD PROGRESS. OUR MORNING SOUNDING SHOWED VERY DRY AIR BELOW
15000 FEET...AND CEILINGS UNDERNEATH THE RAIN SHIELD ARE
STRUGGLING TO GET MUCH BELOW 7000 FEET. RAP FORECAST SOUNDINGS
KEEP IT PRETTY DRY BELOW 850 MB INTO THE AFTERNOON AND FOCUS MUCH
OF THE RAIN ALONG AND WEST OF THE ILLINOIS RIVER. THIS WOULD BE
ASSOCIATED WITH THE SHOWERS THAT ARE CURRENTLY STEADILY MOVING
THROUGH CENTRAL AND SOUTHWEST MISSOURI. THE RADAR ECHOES MOVING
OUT OF SOUTHWEST ILLINOIS ARE ALSO VERY LIGHT...AND THESE WILL BE
MOVING INTO THE SOUTHEAST PART OF THE FORECAST AREA SHORTLY AFTER
MIDDAY.
HAVE SENT SOME UPDATED ZONES/GRIDS TO MAINLY REFINE THE RAIN
TRENDS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO
CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS
MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES
MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS
EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE
DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER
VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD
TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL
ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS
ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE
THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS
ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL
EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER
WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN
CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY
AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE
SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS
GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH
OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE.
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE
GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS
MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER
PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND
BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES
ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE
STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT
WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A
CHANCE OF THUNDER ACROSS THE BOARD TONIGHT.
ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR
ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE
WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW
PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO
TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO
KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER
STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS
HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE
60S.
WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON
SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES
BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE
ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS
LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME
MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING
FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL
INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES.
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS
FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A
PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING
SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS
EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS
FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS
ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE
MAY NEED TO BE REMOVED BY LATER SHIFTS.
ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER
CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON
EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING
NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF
APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT
YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL
SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS
DIPPING INTO THE 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM CDT THU MAY 14 2015
INITIAL BATCH OF SHOWERS HAS BEEN ERODING IN THE DRY AIR OVER
CENTRAL ILLINOIS...BUT STEADIER SHOWERS ARE MOVING NORTHEAST
THROUGH MISSOURI AND SHOULD AFFECT KPIA/KSPI TOWARD MID AFTERNOON.
HAVE NOT MADE MUCH CHANGE TO THE CURRENT TAF SET THROUGH ABOUT
09Z...AS SCATTERED RAIN WILL CONTINUE TO DEVELOP THIS EVENING.
HAVE REMOVED THUNDER MENTION AT KDEC/KCMI AS THE BETTER
INSTABILITY SHOULD BE FURTHER TO THE WEST. STILL HAVE SOME
CONCERNS WITH LLWS POTENTIAL IN THE 03-09Z TIME RANGE...BUT ENOUGH
QUESTIONS REMAIN ON CONVECTIVE POTENTIAL TO HOLD OFF MENTION.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
953 AM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 952 AM CDT THU MAY 14 2015
SHOWERS IN WEST CENTRAL ILLINOIS HAVE BEEN STRUGGLING TO MAKE ANY
EASTWARD PROGRESS. OUR MORNING SOUNDING SHOWED VERY DRY AIR BELOW
15000 FEET...AND CEILINGS UNDERNEATH THE RAIN SHIELD ARE
STRUGGLING TO GET MUCH BELOW 7000 FEET. RAP FORECAST SOUNDINGS
KEEP IT PRETTY DRY BELOW 850 MB INTO THE AFTERNOON AND FOCUS MUCH
OF THE RAIN ALONG AND WEST OF THE ILLINOIS RIVER. THIS WOULD BE
ASSOCIATED WITH THE SHOWERS THAT ARE CURRENTLY STEADILY MOVING
THROUGH CENTRAL AND SOUTHWEST MISSOURI. THE RADAR ECHOES MOVING
OUT OF SOUTHWEST ILLINOIS ARE ALSO VERY LIGHT...AND THESE WILL BE
MOVING INTO THE SOUTHEAST PART OF THE FORECAST AREA SHORTLY AFTER
MIDDAY.
HAVE SENT SOME UPDATED ZONES/GRIDS TO MAINLY REFINE THE RAIN
TRENDS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO
CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS
MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES
MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS
EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE
DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER
VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD
TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL
ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS
ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE
THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS
ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL
EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER
WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN
CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY
AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE
SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS
GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH
OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE.
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE
GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS
MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER
PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND
BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES
ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE
STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT
WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A
CHANCE OF THUNDER ACROSS THE BOARD TONIGHT.
ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR
ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE
WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW
PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO
TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO
KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER
STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS
HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE
60S.
WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON
SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES
BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE
ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS
LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME
MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING
FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL
INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES.
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS
FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A
PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING
SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS
EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS
FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS
ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE
MAY NEED TO BE REMOVED BY LATER SHIFTS.
ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER
CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON
EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING
NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF
APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT
YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL
SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS
DIPPING INTO THE 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 600 AM CDT THU MAY 14 2015
VFR CONDITIONS ARE EXPECTED THRU THE DAY WITH POSSIBLE MVFR CIGS
AFTER 04Z TONIGHT AS A WARM FRONT LIFTS TOWARDS THE AREA. A LARGE
AREA OF LIGHT RAIN WAS MAKING SLOW PROGRESS TO THE EAST AS IT
ENCOUNTERS SOME VERY DRY AIR AT THE LOW LEVELS OF THE ATMOSPHERE.
LATEST RAP FORECAST SOUNDINGS INDICATING CIGS WILL GRADUALLY
LOWER AS THE MOISTURE WORKS ITS WAY INTO OUR AREA TODAY BUT STILL
REMAIN VFR INTO EARLY THIS EVENING. AFTER THAT...PERSISTENT
MOISTURE ADVECTION FROM THE SOUTH WILL BRING ABOUT SOME MVFR CIGS
LATE THIS EVENING AND OVERNIGHT. THE BETTER CHANCES FOR -RA WILL
BE OVER PIA AND SPI TODAY BUT STILL WILL CARRY VCSH OVER AT BMI
AND DEC.
TONIGHT...AS THE BOUNDARY APPROACHES FROM THE SOUTH...WILL INCLUDE
VCTS IN THE FORECAST GROUPS AS WE SEE SOME ELEVATED INSTABILITY
DRAWN NORTHWARD. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 10 TO
15 KTS WITH OCCASIONAL GUSTS TO AROUND 20 KTS. LOOK FOR WINDS TO
VEER MORE INTO THE SOUTH TONIGHT WITH SPEEDS ONCE AGAIN IN THE 10
TO 15 KT RANGE. WILL NEED TO WATCH FOR THE POTENTIAL FOR NON-
CONVECTIVE LOW LEVEL WIND SHEAR OVERNIGHT AS SOUNDINGS INDICATE
40-50 KTS AT 1500-2500 FEET AFTER 03Z. FOR NOW...WITH THE THREAT
FOR SCATTERED TSRA IN THE AREA...WILL HOLD OFF MENTIONING IN THIS
SET OF FORECASTS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
603 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO
CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS
MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES
MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS
EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE
DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER
VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD
TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL
ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS
ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE
THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS
ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL
EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER
WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN
CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY
AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE
SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS
GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH
OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE.
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE
GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS
MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER
PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND
BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES
ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE
STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT
WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A
CHANCE OF THUNDER ACROSS THE BOARD TONIGHT.
ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR
ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE
WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW
PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO
TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO
KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER
STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS
HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE
60S.
WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON
SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES
BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE
ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS
LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME
MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING
FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL
INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES.
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS
FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A
PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING
SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS
EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS
FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS
ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE
MAY NEED TO BE REMOVED BY LATER SHIFTS.
ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER
CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON
EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING
NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF
APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT
YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL
SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS
DIPPING INTO THE 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 600 AM CDT THU MAY 14 2015
VFR CONDITIONS ARE EXPECTED THRU THE DAY WITH POSSIBLE MVFR CIGS
AFTR 04Z TONIGHT AS A WARM FRONT LIFTS TOWARDS THE AREA. A LARGE
AREA OF LIGHT RAIN WAS MAKING SLOW PROGRESS TO THE EAST AS IT
ENCOUNTERS SOME VERY DRY AIR AT THE LOW LEVELS OF THE ATMOSPHERE.
LATEST RAP FORECAST SOUNDINGS INDICATING CIGS WILL GRADUALLY
LOWER AS THE MOISTURE WORKS ITS WAY INTO OUR AREA TODAY BUT STILL
REMAIN VFR INTO EARLY THIS EVENING. AFTER THAT...PERSISTENT
MOISTURE ADVECTION FROM THE SOUTH WILL BRING ABOUT SOME MVFR CIGS
LATE THIS EVENING AND OVERNIGHT. THE BETTER CHANCES FOR -RA WILL
BE OVER PIA AND SPI TODAY BUT STILL WILL CARRY VCSH OVER AT BMI
AND DEC.
TONIGHT...AS THE BOUNDARY APPROACHES FROM THE SOUTH...WILL INCLUDE
VCTS IN THE FORECAST GROUPS AS WE SEE SOME ELEVATED INSTABILITY
DRAWN NORTHWARD. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 10 TO
15 KTS WITH OCCASIONAL GUSTS TO AROUND 20 KTS. LOOK FOR WINDS TO
VEER MORE INTO THE SOUTH TONIGHT WITH SPEEDS ONCE AGAIN IN THE 10
TO 15 KT RANGE. WILL NEED TO WATCH FOR THE POTENTIAL FOR NON-
CONVECTIVE LOW LEVEL WIND SHEAR OVERNIGHT AS SOUNDINGS INDICATE
40-50 KTS AT 1500-2500 FEET AFTR 03Z. FOR NOW...WITH THE THREAT
FOR SCATTERED TSRA IN THE AREA...WILL HOLD OFF MENTIONING IN THIS
SET OF FORECASTS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
205 PM EDT THU MAY 14 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM 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 /TODAY/...
ISSUED AT 1013 AM EDT THU MAY 14 2015
ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER
BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A
DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM
THE MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.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 141800Z TAF ISSUANCE/...
ISSUED AT 1215 PM EDT THU MAY 14 2015
GOOD CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY
EXCEPT PERHAPS BRIEF MVFR TOWARD 12Z IN SCATTERED SHOWERS OR
THUNDERSTORMS. SHOULD BE DRY THROUGH AT LEAST 04Z ACROSS THE
TERMINALS...AND CONFIDENCE IS NOT GOOD ON TIMING A TEMPO GROUP THAT
FAR OUT AT ANY ONE AIRPORT...SO WILL JUST TREND TOWARDS INCREASING
AFTERNOON MID DECK AND INCREASING OVERNIGHT CU DECK.
WINDS WILL START OFF SOUTHEAST AND THEN VEER TO SOUTH AND SOUTHWEST
TONIGHT AND FRIDAY. SPEEDS LOOK TO BE 10 KNOTS OR LESS BUT THEN UP
TO 15 KNOTS AFTER 14Z FRIDAY WITH GUSTS TO 20.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...MRD/RYAN
SHORT TERM...RYAN
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1215 PM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM 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 /TODAY/...
ISSUED AT 1013 AM EDT THU MAY 14 2015
ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER
BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A
DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM
THE MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141800Z TAF ISSUANCE/...
ISSUED AT 1215 PM EDT THU MAY 14 2015
GOOD CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY
EXCEPT PERHAPS BRIEF MVFR TOWARD 12Z IN SCATTERED SHOWERS OR
THUNDERSTORMS. SHOULD BE DRY THROUGH AT LEAST 04Z ACROSS THE
TERMINALS...AND CONFIDENCE IS NOT GOOD ON TIMING A TEMPO GROUP THAT
FAR OUT AT ANY ONE AIRPORT...SO WILL JUST TREND TOWARDS INCREASING
AFTERNOON MID DECK AND INCREASING OVERNIGHT CU DECK.
WINDS WILL START OFF SOUTHEAST AND THEN VEER TO SOUTH AND SOUTHWEST
TONIGHT AND FRIDAY. SPEEDS LOOK TO BE 10 KNOTS OR LESS BUT THEN UP
TO 15 KNOTS AFTER 14Z FRIDAY WITH GUSTS TO 20.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...MRD/RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1021 AM EDT THU MAY 14 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM 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 /TODAY/...
ISSUED AT 1013 AM EDT THU MAY 14 2015
ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER
BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A
DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM
THE MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141200Z TAFS/...
ISSUED AT 630 AM EDT THU MAY 14 2015
LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE
TERMINALS TODAY.
SURFACE WINDS 110-140 DEGREES AT 8-12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...MRD/RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1020 AM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM 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 /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141500Z IND TAF UPDATE/...
ISSUED AT 1020 AM EDT THU MAY 14 2015
NOTHING TO NOTE REGARDING UPDATE.
PREVIOUS DISCUSSION FOLLOWS...
ISSUED AT 630 AM EDT THU MAY 14 2015
LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE
TERMINALS TODAY.
SURFACE WINDS 110-140 DEGREES AT 8-12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS/MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
630 AM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM 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 /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141200Z TAFS/...
ISSUED AT 630 AM EDT THU MAY 14 2015
LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE
TERMINALS TODAY.
SURFACE WINDS 110-140 DEGREES AT 8-12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
423 AM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM 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 /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 140900Z KIND TAF UPDATE/...
ISSUED AT 423 AM EDT THU MAY 14 2015
WILL VEER THE WIND FORECAST AND INCREASE THE SPEEDS SOME ON THE
UPDATE BASED ON CURRENT OBSERVATIONS.
PREVIOUS DISCUSSION FOLLOWS.
VFR THROUGH THE PERIOD.
EXPECT ONLY GRADUALLY INCREASING MID AND HIGH CLOUD THROUGH THE
PERIOD AS HIGH PRESSURE ALOFT AND AT THE SURFACE SLIDE EASTWARD.
WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD.
NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...NIELD/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
329 AM EDT THU MAY 14 2015
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM 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 /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 14/06Z TAFS/...
ISSUED AT 1230 AM EDT THU MAY 14 2015
VFR THROUGH THE PERIOD.
EXPECT ONLY GRADUALLY INCREASING MID AND HIGH CLOUD THROUGH THE
PERIOD AS HIGH PRESSURE ALOFT AND AT THE SURFACE SLIDE EASTWARD.
WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD.
NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
632 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...16/00Z
ISSUED AT 632 PM CDT FRI MAY 15 2015
VFR CONDITIONS THIS EVENING WILL GRADUALLY DETERIORATE LATER
TONIGHT AS FOG AND STRATUS REDEVELOPS...ESPECIALLY TOWARD SUNRISE
SATURDAY MORNING. AT THIS TIME THERE IS MUCH UNCERTAINTY REGARDING
HOW LOW VSBYS/CIGS WILL FALL...BUT GIVEN HOW FRIDAY MORNING TURNED
OUT HAVE CONTINUED TREND OF LOWERING THEM WITH IFR NOW ADVERTISED
AT SOME OF THE TERMINALS. THESE SHORT TERM TRENDS WILL BE
MONITORED CLOSELY OVERNIGHT. OTHERWISE...A FEW SHOWERS AND STORMS
ARE POSSIBLE OVERNIGHT BUT EXPECTED LOW COVERAGE PRECLUDES TAF
MENTION ATTM. SIMILARLY SOME STORMS MAY DEVELOP LATE IN THE DAY
SATURDAY...BUT CONFIDENCE AT THAT RANGE IS TOO LOW FOR MENTION IN
THE 00Z TAFS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CURTIS
LONG TERM...DONAVON
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1248 PM CDT THU MAY 14 2015
.SYNOPSIS...
ISSUED AT 312 AM CDT THU MAY 14 2015
AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN
MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE
PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN
2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE
SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE
WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM
THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION
SHOULD CONTINUE TO BE SEEN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CDT THU MAY 14 2015
TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE
MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY
TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE
BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER
NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP
AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM
ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE
IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER
WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z.
HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST
ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK
LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE
CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY
TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE
HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST
TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS
EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT
LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY
NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10
PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY.
TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE
POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN
FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER
MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF
BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE
NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER
PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT.
MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700
PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT
PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ
VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS
COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS
TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS
MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH.
ERVIN
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU MAY 14 2015
FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN
BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A
LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S.
THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN
INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S
THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN
THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY
COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500
J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY
STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED
SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD.
CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST.
THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT
DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN.
HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY
NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL
FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK
850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER
WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI.
SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED
THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME
HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND
STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL
INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON
FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER
THAN FRIDAY AS WELL.
SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN
CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM
IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND
GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE
ISOLATED.
FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE
SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A
THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION
VECTORS AND PWAT VALUES NEAR 1.50 INCHES.
SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE
FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER
INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT
NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS
DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE
THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE
SFC COLD FRONT.
MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH
DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE
SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR
MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT
PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM CDT THU MAY 14 2015
VFR CIGS WILL BE ERODING FROM THE SOUTHWEST AS RAIN AND SATURATION
PROCESSES MOVE INTO THE TAF SITES. MORE SUBSTANTIAL RAIN MAY STILL
NOT GET INTO THE DBQ VCNTY UNTIL LATE AFTERNOON. HEAVIER SHOWERS WITH
SOME EMBEDDED THUNDER NOW IN CENTRAL TO NORTHEASTERN MO WILL
IMPACT THE BRL TO MLI SITES AFTER 2 PM AND INTO THE EVENING WITH
MVFR CIGS AND VSBYS. AREAS OF RAIN THEN TO PERSIST THROUGH LATE
EVENING/10 PM CDT...BEFORE DIMINISHING. THEN AS A WEAK BOUNDARY
MOVES ACRS THE AREA...SFC WINDS MAY GO LIGHTER SOUTH TO SOUTHWEST
LATE TONIGHT. WITH MORE LLVL MOISTURE BEING ADVECTED UP ACRS THE
REGION...THESE LIGHTER WINDS MAY ALLOW FOR IFR CIGS AND VSBYS FROM
FOG TO FORM AFTER MIDNIGHT AND INTO EARLY FRI MORNING AT ALL TAF
SITES EXCEPT MAYBE FOR DBQ. A LOW CHC FOR MORE SCTRD SHOWERS/
THUNDERSTORMS TO FESTER ALONG AND SOUTH OF THE BRL SITE LATE
TONIGHT. LIGHT SOUTHEAST TO SOUTHWEST WINDS FRI MORNING MAY NOT
INCREASE/MIX ENOUGH TO HELP VSBYS AND CIGS IMPROVE UNTIL AFTER
15Z. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...UTTECH
AVIATION...12
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
626 AM CDT THU MAY 14 2015
.SYNOPSIS...
ISSUED AT 312 AM CDT THU MAY 14 2015
AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN
MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE
PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN
2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE
SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE
WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM
THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION
SHOULD CONTINUE TO BE SEEN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CDT THU MAY 14 2015
TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE
MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY
TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE
BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER
NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP
AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM
ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE
IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER
WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z.
HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST
ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK
LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE
CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY
TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE
HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST
TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS
EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT
LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY
NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10
PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY.
TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE
POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN
FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER
MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF
BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE
NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER
PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT.
MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700
PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT
PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ
VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS
COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS
TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS
MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH.
ERVIN
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU MAY 14 2015
FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN
BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A
LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S.
THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN
INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S
THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN
THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY
COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500
J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY
STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED
SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD.
CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST.
THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT
DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN.
HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY
NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL
FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK
850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER
WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI.
SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED
THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME
HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND
STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL
INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON
FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER
THAN FRIDAY AS WELL.
SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN
CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM
IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND
GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE
ISOLATED.
FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE
SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A
THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION
VECTORS AND PWAT VALUES NEAR 1.50 INCHES.
SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE
FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER
INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT
NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS
DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE
THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE
SFC COLD FRONT.
MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH
DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE
SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR
MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT
PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 615 AM CDT THU MAY 14 2015
A SLOW MOVING BAND OF RAIN WILL MOVE EAST AFFECTING EASTERN IOWA
TERMINALS THROUGH LATE MORNING. CLOUD BASES WILL BE QUITE
HIGH...WITH CIGS AROUND 12000 FT...LOWERING BY AFTERNOON TO
AROUND 5000 FT. A WARM FRONT WILL BRING MORE MOIST AIR TO THE
REGION BY TONIGHT...RESULTING IN CIGS LOWERING TO AROUND 2000 TO
3000 FT...AND VISIBILITIES TO 3 TO 5 MILES IN LIGHT FOG...AND SOME
SHOWERS. CONDITIONS ARE LIKELY TO REMAIN SOMEWHAT VARIABLE AFTER
00Z...WITH PASSING SHOWERS AND EVEN A THUNDERSTORM POSSIBLE.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...UTTECH
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
332 AM CDT THU MAY 14 2015
.SYNOPSIS...
ISSUED AT 312 AM CDT THU MAY 14 2015
AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN
MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE
PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN
2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE
SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE
WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM
THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION
SHOULD CONTINUE TO BE SEEN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CDT THU MAY 14 2015
TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE
MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY
TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE
BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER
NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP
AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM
ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE
IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER
WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z.
HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST
ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK
LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE
CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY
TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE
HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST
TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS
EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT
LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY
NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10
PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY.
TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE
POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN
FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER
MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF
BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE
NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER
PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT.
MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700
PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT
PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ
VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS
COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS
TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS
MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH.
ERVIN
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU MAY 14 2015
FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN
BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A
LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S.
THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN
INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S
THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN
THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY
COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500
J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY
STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED
SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD.
CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST.
THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT
DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN.
HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY
NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL
FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK
850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER
WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI.
SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED
THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME
HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND
STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL
INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON
FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER
THAN FRIDAY AS WELL.
SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN
CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM
IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND
GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE
ISOLATED.
FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE
SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A
THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION
VECTORS AND PWAT VALUES NEAR 1.50 INCHES.
SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE
FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER
INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT
NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS
DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE
THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE
SFC COLD FRONT.
MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH
DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE
SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR
MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT
PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1149 PM CDT WED MAY 13 2015
VFR CONDITIONS WILL CONTINUE 15Z/14 AS CIGS SLOWLY LOWER DUE TO AN
APPROACHING STORM SYSTEM FROM THE PLAINS. AFT 15Z/14 CONDITIONS
WILL SLOWLY DETERIORATE TO MVFR THROUGH 00Z/15. AFT 00Z/15 THERE
IS A SMALL POSSIBILITY OF IFR CIGS DEVELOPING. HOWEVER...THIS
POSSIBILITY WAS NOT INCLUDED IN THE 06Z TAFS DUE TO UNCERTAINTY ON
HOW LOW CLOUD HEIGHTS WILL GET.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...UTTECH
AVIATION...08
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
733 PM CDT FRI MAY 15 2015
...UPDATED AVIATION SECTION...
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 732 PM CDT FRI MAY 15 2015
SOME OF THE CONVECTIVE ALLOWING MODELS INCLUDING THE RAPID REFRESH,
THE 12KM NAM AS WELL AS THE HRRR SEEM TO BE OVERDOING CONVECTIVE
DEVELOPMENT IN THE AREA LATE THIS AFTERNOON/EARLY EVEING. THE
BETTER OPPORTUNITY WILL EVOLVE AS THE JET DYNAMICS BECOME A FACTOR
FOR ASCENT, PROBABLY AFTER MIDNIGHT FOR GCK/HYS/DDC. A WINDOW OF
CONVECTION WILL BE INCLUDED OVERNIGHT AS WELL AS A PROBABILITY
AFTER 18 Z WHEN SEVERE STORMS ARE EXPECTED SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 58 78 53 82 / 50 50 40 0
GCK 57 78 51 79 / 40 40 20 0
EHA 54 75 49 79 / 40 20 10 0
LBL 58 80 51 81 / 50 30 20 0
HYS 61 77 54 79 / 50 60 60 0
P28 62 78 58 83 / 40 50 50 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...BURGERT
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
316 PM CDT THU MAY 14 2015
.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 1208 PM CDT THU MAY 14 2015
VERY LIGHT RAIN SHOWERS/SPRINKLES STILL MOVING SLOWLY EAST ACROSS
THE AREA...SOME OF WHICH IS NOT HITTING THE GROUND. NOT PLANNING
ON MENTION IN THE TAFS. OTHERWISE MAINLY HIGH CLOUDS WITH A FEW
MID CLOUDS. VFR CONDITIONS THE RULE. LIGHT ESE WINDS WILL
GRADUALLY VEER THROUGH 18Z FRIDAY...LIGHT THROUGH TONIGHT THEN SSW
UP TO 10 KTS BY LATE MORNING FRIDAY.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...CN
AVIATION...CN
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1017 PM CDT FRI MAY 15 2015
.DISCUSSION...
LIFT ASSOCIATED WITH A SHORTWAVE TROF LIFTING THROUGH EASTERN TX
ALONG WITH A DEEP MSTR POOL PER KLIX 00Z RAOB HELPING TO
SUSTAIN/GENERATE CONVECTION ACROSS SOUTH CENTRAL/SOUTHEAST LA AND
THE ADJACENT COASTAL WATERS. POP/WX/QPF GRIDS WERE ADJUSTED IN THE
SHORT TERM BASED PRIMARILY ON THE HRRR AND RADAR TRENDS...WITH A
NOD TO THE FORMER OVERNIGHT WHICH SHOWS ISOLATED TO PERHAPS
SCATTERED ACTIVITY CONTINUING EAST OF THE SABINE RIVER. MINOR
TWEAKS TO REMAINING GRIDS...WITH A SLIGHT INCREASE IN WIND/WIND
GUST GRIDS REQUIRING A SCEC HEADLINE OVER THE GULF WATERS.
13
&&
.PREV DISCUSSION... /ISSUED 650 PM CDT FRI MAY 15 2015/
AVIATION...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE OVER
CENTRAL LOUISIANA INTO ACADIANA. REMAINDER OF THE AREA IS CLEAR OF
ANY PRECIP. MUCH OF THIS ACTIVITY WILL BE DYING OFF IN THE NEXT
FEW HOURS WITH COOLING. WILL HOWEVER MAINTAIN VCSH THROUGH THE
NIGHT AT LFT AND ARA WITH ACTIVITY NOTED OFFSHORE FROM THESE
SITES. OTHERWISE...VFR ONGOING OVER THE AREA AT THIS TIME.
EXPECTING ANOTHER ROUND OF MVFR STRATOCU TO DEVELOP AS THE NIGHT
PROGRESSES. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO RETURN
AREA-WIDE SATURDAY MORNING...TRANSITIONING TO TSRA FOR THE
AFTERNOON.
PREV DISCUSSION... /ISSUED 325 PM CDT FRI MAY 15 2015/
DISCUSSION...AN UPPER TROUGH REMAINS ACROSS THE WEST HALF OF THE
COUNTRY THIS AFTERNOON WITH MULTIPLE SHORT WAVES ROTATING AROUND THE
LARGER GYRE. ONE SHORT WAVE IS PUSHING THROUGH THE EAST HALF OF TX
WITH A LINE OF STORMS PUSH ACROSS THE CENTRAL TX COAST. FARTHER
EAST ACROSS DEEP SE TX AND LA WHERE THE HEATING OF THE DAY HAS
COMBINED WITH THE UPPER DIVERGENCE IN PLACE TO DEVELOP SCT TO
NUMEROUS SHOWERS AND STORMS AWAY FROM THE COAST. AS SUNSET
APPROACHES CONVECTION IS EXPECTED TO DECREASE INCLUDING THE
CENTRAL TX COAST QLCS, HOWEVER AREAS OF RAIN MAY MOVE INTO THE
WEST HALF OF THE CWA AS THE REMNANTS OF THE LINE OF STORMS DRAWS
CLOSER AND ADDITIONAL SCT STORMS MAY REDEVELOP LATER IN THE NIGHT
AS THE SHORT WAVE MOVES IN. A SIMILAR SITUATION IS EXPECTED FOR
SAT AND SUN AS CONVECTION WILL REDEVELOP EACH AFTERNOON AND
GRADUALLY DECREASE THROUGH THE LATE AFTERNOON AND EARLY EVENING.
A SLIGHT INCREASE IN COVERAGE IS EXPECTED MONDAY AND TUESDAY AS THE
LARGER WESTERN TROUGH AXIS MOVES ACROSS THE REGION.
FROM MID WEEK ON MORE TYPICAL EARLY SUMMER WEATHER IS EXPECTED
WITH ISOLATED TO WIDELY SCT AFTERNOON STORMS OCCUR UNDER WEAK
RIDGING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 70 85 72 87 / 20 60 30 50
LCH 74 85 75 86 / 30 40 20 40
LFT 72 86 74 87 / 40 50 30 40
BPT 75 86 75 86 / 20 30 20 40
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL 6 AM CDT SATURDAY FOR GMZ450-
452-455-470-472-475.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
746 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 /00Z SATURDAY THROUGH WEDNESDAY/...
SFC HI PRES WILL SLIDE FARTHER INTO THE ATLC...WHILE WEAK LO PRES
MOVES ACRS THE ERN GRT LKS AND TWD NRN NEW ENGLAND TNGT THRU SAT.
HAVE MAINTAINED VFR CONDITIONS THRU THE 00Z TAF PERIOD. FLO WILL
BECOME SSW ALL AREAS TNGT...WITH A CONTINUATION OF MAINLY MID/HI
CLOUDS FM 12-25 K FT. SOME OF THE GUIDANCE TRIES TO BRING LO CIGS
INTO THE REGION ARND 12Z SAT MORNG. BUT..THIS SEEMS UNLIKELY
GIVEN A SW FLO AND ONLY A SHALLOW LAYER OF LOW LEVEL MOISTURE. SO
HAVE NOT INCLUDED IN TAFS.
HI BECOMES NEARLY STATIONARY OFF THE MID ATLC CST THRU THE WEEKEND
INTO EARLY NEXT WEEK...AND GENERALLY VFR CONDITIONS WILL PREVAIL.
WARMER AIRMASS/INCREASING MOISTURE COULD RESULT IN ISLTD/WIDELY
SCATTERED TSTMS MAINLY IN THE LATE AFTN AND EVENING HRS (ESPLY
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/TMG
MARINE...MAS/JAO
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
655 PM CDT Fri May 15 2015
...Mesoscale Discussion and Aviation Update...
.MESOSCALE DISCUSSION...
Issued at 639 PM CDT FRI MAY 15 2015
Scattered thunderstorms have developed near the Highway 65
corridor early this evening in an uncapped air mass. These
storms are being triggered by an area of upper level
divergence/700-500 mb omega. This area of scattered convection
will shift northeast this evening and should become a bit more
aligned with the I-44 corridor.
While deep layer shear is a little on the weak side across
southern Missouri (20-25 knots), MLCAPE values around 1500 J/kg
may support some hail and gusty winds with a few stronger
updrafts. Deep layer shear across central Missouri is a bit
stronger, so storms up that way will have the "best" potential for
hail/wind.
&&
.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 00Z TAFS through 00Z Saturday Evening)
Issued at 639 PM CDT FRI MAY 15 2015
Scattered thunderstorms will impact the Springfield terminal early
this evening bringing MVFR conditions. Mainly VFR conditions are
then expected overnight across the region as thunderstorms
diminish. Weather models are then indicating the potential for
another area of scattered showers and thunderstorms moving into
southern Missouri Saturday morning. MVFR conditions will again be
possible during this period. Outside of thunderstorms, southerly
winds will increase on Saturday and will become gusty in the
afternoon.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...Schaumann
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Schaumann
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
930 AM MDT THU MAY 14 2015
.UPDATE...
MADE A FEW CHANGES TO THE FORECAST THROUGH THIS EVENING. STRATUS
HAD OVERSPREAD THE AREA WITH THE EXCEPTION OF THE MOUNTAINS AND
NEARBY FOOTHILLS. MID CLOUDS WERE MOVING N OVER THE WESTERN ZONES
IN THE MOIST FLOW AHEAD OF THE UPPER LOW ALONG THE W COAST. IN
GENERAL...HAVE INCREASED CLOUD COVER OVER MOST OF THE AREA THROUGH
THE DAY. RAP SOUNDINGS DID SHOW CLOUDS IN THE E DISSIPATING THIS
AFTERNOON SO REFLECTED THIS IN THE GRIDS. ALSO WEBCAMS/SURFACE
OBSERVATIONS INDICATED PATCHY FOG OVER MOST OF THE AREA...SO HAVE
SPREAD THE FOG MENTION FURTHER W THROUGH 18Z. DUE TO THE CLOUD
COVER...HAVE LOWERED TEMPERATURES A COUPLE OF DEGREES TOWARD THE
NEW WRF. THE CLOUDS WILL INHIBIT THUNDERSTORM FORMATION...SO HAVE
CONFINED THUNDER TO THE SUNNIER AREAS...IE...THE MOUNTAINS AND
FOOTHILLS THIS AFTERNOON AND EVENING. SREF SHOWED GOOD
PROBABILITIES OF 500 J/KG OF SURFACE CAPE IN THESE AREAS...WITH
CAPES DIMINISHING QUICKLY THIS EVENING. RAP SHOWED MARGINAL SHEAR
OVER THE AREA.
NEW WRF SHOWED DRY SLOT MOVING N QUICKLY LATE TONIGHT WHICH WOULD
CONTRADICT THE HIGH POPS AFTER 06Z. WILL WAIT TIL MORE GUIDANCE
COMES IN BEFORE MAKING ANY CHANGES LATE TONIGHT. ARTHUR
&&
.SHORT TERM...VALID FOR TDY AND FRI...
MINIMAL CHANGES TO THE SHORT TERM FORECAST PERIOD...AS UNSETTLED
PATTERN PERSISTS. MODELS HAVE BEEN CONSISTENT WITH THIS
PATTERN FOR SEVERAL DAYS...SO FORECAST IS IN GOOD SHAPE OVERALL.
DIFFLUENT FLOW ALOFT AHEAD OF APPROACHING UPPER LEVEL PACIFIC LOW
PRESSURE SYSTEM...AND PERSISTENT UPSLOPE SFC FLOW PREVAIL ACROSS
THE REGION FOR TODAY AND FRIDAY. INCREASING MOISTURE AVAILABILITY
AND SHORTWAVE ACTIVITY ARE ALSO EXPECTED THROUGH THE
PERIOD...RESULTING IN INCREASING CHANCES FOR PRECIPITATION.
ADDITIONALLY...IMPROVED CAPES AND SHEAR PROFILE THROUGH THE
TODAY...WILL LEND SUPPORT FOR INCREASED CHANCES OF THUNDER TODAY
AND INTO TONIGHT. BEST CHANCES TODAY WILL BE FROM SHERIDAN TO
BILLINGS AND WEST THROUGH THIS AFTERNOON...AND SPREADING EASTWARD
THROUGH THIS EVENING AND TONIGHT. SHOWERS WILL BE MORE WIDESPREAD
ON FRIDAY. SHEAR AND CAPE DO NOT APPEAR QUITE AS GOOD FOR
FRIDAY...AND WILL ALSO HAVE LIMITED POTENTIAL FOR ADDITIONAL
ENERGY FROM DIURNAL HEATING WITH CLOUD COVER. SO THUNDER POTENTIAL
APPEARS A BIT LOWER FOR FRIDAY...BUT HAVE STILL KEPT A MENTION OF
THUNDER AT THIS TIME.
TEMPS WILL STILL HAVE A CHANCE TO WARM UP...BUT COOLING TREND
WILL BEGIN TODAY. HIGHS IN THE UPPER 50S TO UPPER 60S ARE
EXPECTED. CLOUD COVER ACROSS THE REGION...AND PERSIST SHOWER
ACTIVITY ON FRIDAY WILL LIMIT TEMPS TO MAINLY THE 50S. SOME AREAS
ALONG THE SOUTHERN BORDER MAY CREEP INTO THE 60S...BUT WILL
GREATLY DEPEND ON HOW FAR NORTH DRY SLOTTING OCCURS. AAG
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
WET WEATHER COMING THIS WEEKEND THOUGH THERE ARE STILL SOME
DETAILS TO BE WORKED OUT.
ENERGY EMERGING FROM DEEP WESTERN CONUS LOW WILL LIFT OUT OF WY
FRIDAY NIGHT AND CLOSE OFF SOMEWHERE OVER SOUTHEAST MT ON
SATURDAY. GOOD GENERAL CONSENSUS AMONG THE MODELS HERE BUT THE
EXACT LOCATION OF THE MID LEVEL LOW WILL BE CRUCIAL. WILL CONTINUE
TO FOLLOW A MODEL BLEND IN THIS REGARD. BEST CHANCE OF RAIN
SATURDAY WILL BE FROM BILLINGS WEST AND NORTHWARD...WITH DRY
SLOTTING A REAL POSSIBILITY IN FAR SOUTHEAST MT AND SHERIDAN
COUNTY. BILLINGS MAY NOT FAR FROM THE EDGE BUT ALL MODELS TAKE MID
LEVEL LOW TO OUR EAST WHICH WOULD SUGGEST PLENTY OF RAIN FOR THE
METRO AREA ON SATURDAY. IF THE LOW WERE TO TRACK JUST SLIGHTLY
WEST WE COULD SEE A BREAK IN THE PCPN. OVER TIME AS THE LOW SHIFTS
EAST WE WILL SEE TROWAL WRAP BACK THROUGH OUR AREA AS THE FLOW
TURNS NORTHERLY. THIS WILL RESULT IN WIDESPREAD PCPN SATURDAY
NIGHT INTO SUNDAY. LOW WILL DEPART SUNDAY AFTERNOON AND NIGHT WITH
DRIER AIR ADVECTING IN FROM THE NORTH. AS FOR PCPN AMOUNTS...GFS
SEEMS TO BE SUFFERING SOME CONVECTIVE FEEDBACK ISSUES BUT A MODEL
BLEND WILL STILL PRODUCE A WIDESPREAD 1-2 INCHES WITH LOCALLY
HIGHER AMTS...IE MAYBE 3 INCHES...AIDED BY CONVECTIVE ENHANCEMENT
PRIOR TO THE SATURDAY TROWAL. SHOULD ALSO BE NOTED THAT GULF
MOISTURE WILL BE INVOLVED SO MOISTURE AVAILABILITY WILL NOT BE AN
ISSUE THROUGH THE COURSE OF THIS EVENT.
MOUNTAINS COULD SEE SIGNIFICANT SNOWFALL ESPECIALLY BEGINNING
SATURDAY NIGHT AS WE COLD ADVECT AND 700MB TEMPS FALL TO NEAR -5C.
WILL ALSO NEED TO KEEP AN EYE ON CLIPPER WHICH WILL EMERGE FROM
THE CANADIAN ARCTIC AND PUSH THROUGH SASKATCHEWAN BY SATURDAY
NIGHT. THIS WILL BE ASSOCIATED WITH A LOW LEVEL COLD SURGE WHICH
COULD DROP 850MB TEMPS TO NEAR 0C BY SUNDAY. IT IS NOT OUT OF THE
QUESTION THAT SOME OF THE HIGHER HILLS OF SOUTHEAST MT COULD SEE
A MIX WITH WET SNOW ON SUNDAY PRIOR TO THE DRYING.
SHORTWAVE RIDGE WILL BUILD IN SUNDAY NIGHT AND MONDAY FOR A BRIEF
PERIOD OF QUIETER WEATHER. NEXT PACIFIC TROF WILL MOVE INTO THE
WESTERN CONUS AND SET THE STAGE FOR ANOTHER PERIOD OF UPPER
DIFFLUENT FLOW...GULF MOISTURE ADVECTION AND A GOOD CHANCE OF
SHOWERS IN OUR REGION FROM MONDAY NIGHT THROUGH WEDNESDAY. ANOTHER
WIDESPREAD PCPN EVENT IS A POSSIBILITY AS SUGGESTED BY THE MOST
RECENT GFS.
TEMPERATURES WILL BE WELL BELOW NORMAL THIS WEEKEND WITH MOST
AREAS SEEING HIGHS ONLY IN THE 50S. SHOULD SEE SOME MODEST
MODERATION NEXT MONDAY/TUESDAY BUT WITH A PERSISTENT EAST WIND
REGIME KEEPING OUR TEMPS IN CHECK. TEMPS SHOULD STAY BELOW NORMAL
THROUGH THE MIDDLE OF NEXT WEEK.
JKL
&&
.AVIATION...
AREA OF STRATUS WITH MVFR TO LOCAL IFR CEILINGS WILL IMPACT OUR
ENTIRE AREA THIS MORNING...THE EXCEPTION BEING KLVM...KSHR AND THE
FOOTHILLS LOCATIONS WHERE VFR CONDITIONS WILL PREVAIL. CONDITIONS
ARE EXPECTED TO IMPROVE TO VFR BY 18Z. SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG AND WEST OF A KSHR- KBIL LINE
THIS AFTERNOON AND EVENING. MVFR CONDITIONS WILL BE POSSIBLE IN
ANY SHOWER/THUNDERSTORM ACTIVITY. THE MOUNTAINS WILL BE OBSCURED
AT TIMES. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 064 048/056 045/053 041/052 038/060 041/056 042/055
2/W 66/T 78/W 76/W 22/W 24/W 55/W
LVM 058 044/056 040/053 038/054 035/058 037/055 038/057
4/T 56/T 78/W 75/W 23/T 35/W 54/W
HDN 068 047/060 045/055 041/052 035/063 041/059 041/057
1/E 56/T 67/W 76/W 22/W 24/W 55/W
MLS 065 046/058 046/058 041/052 035/058 040/058 041/058
1/B 36/T 87/T 77/W 21/B 23/W 44/W
4BQ 066 047/058 046/062 042/049 032/059 039/055 039/055
1/B 46/T 75/T 77/W 21/B 34/W 55/W
BHK 061 042/058 045/063 041/049 031/055 036/055 038/055
1/B 16/T 85/T 66/W 21/B 23/W 44/W
SHR 064 044/061 041/056 038/050 034/058 040/055 038/055
2/T 66/T 56/W 77/W 22/T 35/W 55/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1253 PM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT THU MAY 14 2015
TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN
SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT
TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE
PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST
AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE
TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR
HIGHS IN THE 70S TO 80 SOUTH.
WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH
A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM
SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH
THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE
VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO
LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING
SCATTERED TSTMS FROM 06Z ONWARD.
INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE
COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY
LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN
DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE
GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS
WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH
HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU MAY 14 2015
LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE.
DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT
WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE
MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED
CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH
PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY
SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS
REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA
OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING
DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM
FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT
PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS
EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E
AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE
AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND
STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT
FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES
LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL
JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND
ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD
TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL
UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR
FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE
AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING
FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE
WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE
STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN
THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE
INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS
AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF
DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION.
THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING
LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST
KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE
OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE.
MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY
EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY
RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM
THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM
INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND
AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE
INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY
UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL
LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING
WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK
NORTH AND EAST THROUGH THE EVENING.
A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK
BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION
CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES
ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL
CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES
NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE
TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT
SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS
AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE
CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7
RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR
WIDESPREAD QPF AND STRONG MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1250 PM CDT THU MAY 14 2015
VFR CONDITIONS EXPECTED FOR THE AFTERNOON...ALTHOUGH CAN NOT RULE
OUT A BRIEF MVFR CIG ACROSS NRN NEB EARLY.
OVERNIGHT A DISTURBANCE WILL LIFT NORTHEAST ACROSS THE AREA...WITH
A BAND OF THUNDERSTORMS EXPECTED. IMPACT TO SW NEB AFTER
MIDNIGHT...THEN MOVING NORTHEAST THROUGH EARLY MORNING. THE
THUNDERSTORMS WILL LIKELY BRING MVFR OR IFR CIGS THAT COULD LINGER
AFTER THE THUNDERSTORMS LIFT INTO S DAKOTA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
732 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY BE A BIT MORE CONCERNED
ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY BECOME MORE SOUTHWESTERLY IF
NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU MAY 14 2015
A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED
PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE
LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES
TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS.
OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE
PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA
SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING
BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK.
STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE
ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL
AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS
ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE
MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM
SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR
60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL
AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL
SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE
AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED
RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO
DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND
GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO.
AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY...
EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE
LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE
LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD
CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE
THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY
AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW
HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER.
CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN
APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT
WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE
TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO
FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL
DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS
TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR
SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS
INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID
WEEK TO BE MORE ISOLATED ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 722 AM CDT THU MAY 14 2015
MVFR CONDITIONS ARE EXPECTED AT THE TERMINAL SITES THROUGH THE
BEGINNING HOURS OF THE TAF FOR LOW CEILINGS...HOWEVER...LATER THIS
AFTERNOON CONDITIONS SHOULD IMPROVE TO VFR HAS CLOUD BASES LIFT.
WIND SPEEDS SHOULD ALSO GO LIGHT AND VARIABLE NEAR 00Z...WITH
CONFIDENCE HIGH REGARDING MINIMAL IMPACTS AT THE TERMINALS
WEATHER-WISE THOUGH MOST OF THE AFTERNOON/EVENING. CONFIDENCE
BEGINS TO DECREASE WHEN WE STARTING TALKING ABOUT THUNDERSTORM
POTENTIAL LATE TONIGHT INTO TOMORROW MORNING. CHANCES ARE THERE
COULD BE SOME THUNDERSTORMS IN THE VICINITY OF THE TERMINALS...BUT
CURRENT TRENDS APPEAR TO BE BACKING OFF THIS SCENARIO. THAT BEING
SAID...THUNDERSTORMS ARE EXPECTED AFTER MIDNIGHT ACROSS THE AREA
WITH CHANCES LOOKING TO BE CLOSER TO 12Z...WHICH IS LATER THAN
THE PREVIOUS TAF INITIALLY SUGGESTED. CONFIDENCE IN THUNDERSTORM
DEVELOPMENT AND COVERAGE SHOULD BECOME CLEARER WITH SUBSEQUENT
TAFS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...GUERRERO
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
621 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT THU MAY 14 2015
TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN
SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT
TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE
PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST
AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE
TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR
HIGHS IN THE 70S TO 80 SOUTH.
WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH
A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM
SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH
THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE
VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO
LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING
SCATTERED TSTMS FROM 06Z ONWARD.
INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE
COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY
LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN
DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE
GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS
WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH
HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU MAY 14 2015
LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE.
DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT
WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE
MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED
CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH
PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY
SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS
REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA
OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING
DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM
FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT
PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS
EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E
AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE
AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND
STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT
FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES
LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL
JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND
ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD
TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL
UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR
FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE
AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING
FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE
WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE
STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN
THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE
INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS
AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF
DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION.
THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING
LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST
KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE
OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE.
MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY
EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY
RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM
THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM
INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND
AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE
INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY
UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL
LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING
WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK
NORTH AND EAST THROUGH THE EVENING.
A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK
BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION
CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES
ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL
CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES
NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE
TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT
SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS
AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE
CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7
RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR
WIDESPREAD QPF AND STRONG MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 620 AM CDT THU MAY 14 2015
IMPROVEMENT TO VFR IS EXPECTED 15Z-18Z THIS MORNING...LARGELY THE
RESULT OF MIXING PROCESSES. OTHERWISE...SATELLITE TIMING TOOLS
SUGGEST MVFR WOULD LAST ALL DAY EAST OF HIGHWAY 61.
TONIGHT...AN UPPER LEVEL DISTURBANCE ACROSS AZ SHOULD MOVE THROUGH
THE FCST AREA. THE MODELS SUGGEST SCATTERED TSTMS WILL DEVELOP AS
THE DISTURBANCE MOVES THROUGH THE FCST AREA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
607 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY BE A BIT MORE CONCERNED
ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY BECOME MORE SOUTHWESTERLY IF
NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU MAY 14 2015
A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED
PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE
LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES
TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS.
OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE
PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA
SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING
BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK.
STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE
ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL
AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS
ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE
MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM
SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR
60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL
AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL
SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE
AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED
RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO
DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND
GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO.
AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY...
EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE
LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE
LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD
CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE
THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY
AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW
HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER.
CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN
APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT
WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE
TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO
FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL
DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS
TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR
SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS
INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID
WEEK TO BE MORE ISOLATED ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 606 AM CDT THU MAY 14 2015
ALTHOUGH CONFIDENCE REMAINS FAIRLY HIGH THAT A MULTI-HOUR PERIOD
OF VFR CEILING/VISIBILITY WILL MATERIALIZE BEYOND THE FIRST 6-8
HOURS OF THE PERIOD (POTENTIALLY LASTING WELL INTO THE
NIGHT)...MVFR/IFR CEILING AND VISIBILITY WILL CONTINUE TO BE THE
MAIN ISSUE THIS MORNING INTO EARLY THIS AFTERNOON...ALONG WITH A
FEW HOURS OF LIGHT DRIZZLE POTENTIAL. OBVIOUSLY TIMING IN THE
SPECIFICS OF THE RETURN TO VFR CONDITIONS IS SOMEWHAT
UNCERTAIN...BUT WILL CONTINUE TO AIM FOR VFR VISIBILITY BY LATE
MORNING AND VFR CEILING BY AROUND 20Z THIS AFTERNOON. DURING THE
LATTER HALF OF THE PERIOD...HAVE BROUGHT IN A VICINITY
THUNDERSTORM (VCTS) MENTION FOR LATE TONIGHT...WITH SOME SMALL
HAIL POSSIBLE SHOULD ANY OF THESE STORMS DIRECTLY AFFECT THE
TERMINALS. CANNOT RULE OUT SOME SUB-VFR CEILING/VISIBILITY AGAIN
TONIGHT AS WELL...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO GO THERE
YET. WIND-WISE...FAIRLY LIGHT BREEZES ONLY AROUND 10KT OR LESS
SHOULD PREVAIL THROUGH THE PERIOD...WITH DIRECTION TRANSITIONING
FROM SOUTH RIGHT AWAY THIS MORNING...TO SOUTHWEST MOST OF THE
DAY...AND THEN SOUTHEAST THIS EVENING/TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
420 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY A BIT MORE CONCERNED ABOUT
POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY MORE SOUTHWESTERLY IF NOT
WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU MAY 14 2015
A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED
PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE
LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES
TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS.
OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE
PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA
SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING
BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK.
STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE
ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL
AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS
ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE
MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM
SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR
60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL
AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL
SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE
AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED
RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO
DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND
GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO.
AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY...
EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE
LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE
LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD
CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE
THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY
AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW
HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER.
CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN
APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT
WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE
TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO
FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL
DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS
TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR
SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS
INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID
WEEK TO BE MORE ISOLATED ACROSS THE REGION.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 100 AM CDT THU MAY 14 2015
OVERALL NO MAJOR CHANGES FROM PREVIOUS 00Z PACKAGE...AS A
COMBINATION OF MVFR/IFR CONDITIONS ARE EXPECTED TO DOMINATE AT
LEAST THE FIRST HALF OF THE PERIOD...AND POSSIBLY A FEW HOURS
BEYOND...WITH VFR CEILING/VISIBILITY THEN RETURNING FROM ROUGHLY
MID-AFTERNOON ONWARD. WHILE THIS GENERAL TREND CARRIES FAIRLY HIGH
CONFIDENCE...THERE ARE PLENTY OF QUESTION MARKS ESPECIALLY WITH
REGARD TO VISIBILITY...AND WHETHER OR NOT AT LEAST A BRIEF PERIOD
OF MORE SUBSTANTIAL FOG COULD SET IN BEHIND THE RAIN SHIELD THIS
MORNING...BUT FOR NOW HAVE NOT GONE TOO PESSIMISTIC DOWN THIS
ROAD. SPEAKING OF RAIN...AT LEAST THROUGH THESE FIRST 5-6 HOURS
OR SO...A FAIRLY STEADY LIGHT RAIN WILL PERSIST AT BOTH TERMINALS
BEFORE POSSIBLY TRANSITIONING TO A FEW HOURS OF LIGHT DRIZZLE
BEFORE PRECIP ENDS COMPLETELY. WILL AIM FOR A RETURN TO PREVAILING
VFR VISIBILITY BY MID-LATE MORNING...BUT WILL HOLD ONTO AN MVFR
CEILING INTO MID-AFTERNOON BEFORE SCATTERING OUT/LIFTING TO VFR
LEVELS. CONFIDENCE IS FAIRLY HIGH IN VFR CONDITIONS FOR THE LATTER
SEVERAL HOURS OF THE PERIOD THURSDAY EVENING. THERE IS AN OUTSIDE
CHANCE THAT ISOLATED SHOWERS/THUNDERSTORMS COULD BE STARTING TO
DEVELOP IN THE GENERAL AREA TOWARD THE VERY END OF THE
PERIOD...BUT THIS SEEMS MORE LIKELY DURING THE FOLLOWING 6 HOURS
SO WILL HOLD OFF ON ANY MENTION FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
359 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY A BIT MORE CONCERNED ABOUT
POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY MORE SOUTHWESTERLY IF NOT
WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 400 AM CDT THU MAY 14 2015
THIS SECTION WILL BE ADDED WITHIN THE NEXT HOUR...STAY TUNED.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 100 AM CDT THU MAY 14 2015
OVERALL NO MAJOR CHANGES FROM PREVIOUS 00Z PACKAGE...AS A
COMBINATION OF MVFR/IFR CONDITIONS ARE EXPECTED TO DOMINATE AT
LEAST THE FIRST HALF OF THE PERIOD...AND POSSIBLY A FEW HOURS
BEYOND...WITH VFR CEILING/VISIBILITY THEN RETURNING FROM ROUGHLY
MID-AFTERNOON ONWARD. WHILE THIS GENERAL TREND CARRIES FAIRLY HIGH
CONFIDENCE...THERE ARE PLENTY OF QUESTION MARKS ESPECIALLY WITH
REGARD TO VISIBILITY...AND WHETHER OR NOT AT LEAST A BRIEF PERIOD
OF MORE SUBSTANTIAL FOG COULD SET IN BEHIND THE RAIN SHIELD THIS
MORNING...BUT FOR NOW HAVE NOT GONE TOO PESSIMISTIC DOWN THIS
ROAD. SPEAKING OF RAIN...AT LEAST THROUGH THESE FIRST 5-6 HOURS
OR SO...A FAIRLY STEADY LIGHT RAIN WILL PERSIST AT BOTH TERMINALS
BEFORE POSSIBLY TRANSITIONING TO A FEW HOURS OF LIGHT DRIZZLE
BEFORE PRECIP ENDS COMPLETELY. WILL AIM FOR A RETURN TO PREVAILING
VFR VISIBILITY BY MID-LATE MORNING...BUT WILL HOLD ONTO AN MVFR
CEILING INTO MID-AFTERNOON BEFORE SCATTERING OUT/LIFTING TO VFR
LEVELS. CONFIDENCE IS FAIRLY HIGH IN VFR CONDITIONS FOR THE LATTER
SEVERAL HOURS OF THE PERIOD THURSDAY EVENING. THERE IS AN OUTSIDE
CHANCE THAT ISOLATED SHOWERS/THUNDERSTORMS COULD BE STARTING TO
DEVELOP IN THE GENERAL AREA TOWARD THE VERY END OF THE
PERIOD...BUT THIS SEEMS MORE LIKELY DURING THE FOLLOWING 6 HOURS
SO WILL HOLD OFF ON ANY MENTION FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT THU MAY 14 2015
TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN
SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT
TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE
PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST
AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE
TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR
HIGHS IN THE 70S TO 80 SOUTH.
WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH
A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM
SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH
THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE
VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO
LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING
SCATTERED TSTMS FROM 06Z ONWARD.
INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE
COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY
LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN
DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE
GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS
WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH
HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU MAY 14 2015
LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE.
DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT
WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE
MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED
CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH
PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY
SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS
REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA
OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING
DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM
FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT
PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS
EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E
AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE
AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND
STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT
FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES
LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL
JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND
ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD
TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL
UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR
FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE
AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING
FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE
WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE
STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN
THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE
INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS
AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF
DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION.
THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING
LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST
KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE
OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE.
MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY
EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY
RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM
THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM
INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND
AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE
INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY
UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL
LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING
WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK
NORTH AND EAST THROUGH THE EVENING.
A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK
BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION
CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES
ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL
CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES
NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE
TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT
SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS
AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE
CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7
RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR
WIDESPREAD QPF AND STRONG MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1125 PM CDT WED MAY 13 2015
FOR THE KLBF TERMINAL...LOOK FOR RAIN SHOWERS TO COME TO AN END BY
07Z THURSDAY. PATCHY FOG WILL FOLLOW THE RAIN SHOWERS WITH CIGS
FALLING AS LOW AS 400 FT AGL WITH VISBYS DOWN TO 2SM. CIGS WILL
IMPROVE BY MID MORNING THURSDAY WITH MVFR CIGS OF 1500 FT AGL.
SKIES WILL CLEAR THURSDAY AFTERNOON AND REMAIN CLEAR THROUGH 06Z
FRIDAY. FOR THE KVTN TERMINAL...EXPECT LIGHT RAIN SHOWERS TO
CONTINUE THROUGH 10Z THURSDAY WITH PATCHY FOG POSSIBLE THEREAFTER
THROUGH MID MORNING THURSDAY. CIGS MAY FALL AS LOW AS 700 FT
OVERNIGHT WITH VISBYS DOWN TO 4SM. MVFR CIGS AROUND 1500 FT AGL
WILL DEVELOP AFTER MID MORNING...WITH VFR CIGS OF 5000 FT AGL
EXPECTED THURSDAY AFTERNOON. SKIES WILL CLEAR THURSDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1149 PM CDT WED MAY 13 2015
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
TONIGHT
LATEST SHORT TERM PROGS IN AGREEMENT SHOWING THAT GOING RAINFALL
FCST FOR TONIGHT IS ON TRACK WITH PCPN ACTIVITY DEVELOPING OVER KS
THEN EXPANDING NWD INTO THE CWA EARLY THIS EVENING. GIVEN
COMBINATION OF UPPER SUPPORT VIA POTENT VORT MAX/STRONG DIVG
WORKING IN TANDEM WITH RATHER MOIST 305K UPGLIDE...SEEMS
REASONABLE TO ASSUME THAT SEVERAL LOCATIONS SHOULD SEE RAINFALL
TOTALS OF AT LEAST HALF AN INCH MAINLY OVER THE SRN CWA WHERE
LIFT/MOISTURE WILL BE MORE PREVALENT. IN ADDITION...MODELS ARE
SHOWING INSTABILITY PARAMETERS WILL BE WEAK AT BEST SO ANY TSTM
DEVELOPMENT SHOULD BE ISOLATED.
DEE
THURSDAY THROUGH SATURDAY
TIMING AND POTENTIAL FOR SEVERE STORMS BOTH FRIDAY AND SATURDAY
WILL BE THE MAIN FORECAST CONCERNS.
OUR AREA WILL GENERALLY BE IN SOUTH OR SOUTHWEST MID TROPOSPHERIC
FLOW THE NEXT FEW DAYS. WATER VAPOR IMAGERY EARLY THIS WEDNESDAY
AFTERNOON...IN COMBINATION WITH EARLY AFTERNOON RAP MODEL
INTITIALIZATIONS...SHOWED FAIRLY IMPRESSIVE SHORTWAVE TROUGH FROM
COLORADO DOWN INTO WEST TEXAS. THIS WILL LIFT NORTHEAST ACROSS THE
AREA TONIGHT AND THURSDAY. BRIEF SHORTWAVE RIDGING BUILDS IN FOR
LATE THURSDAY/EARLY THURSDAY NIGHT...WHILE A STRONG CLOSED LOW
DIGS DOWN INTO NEVADA AND CALIFORNIA. GENERAL MODEL CONSENSUS
SHOWS THE CENTER OF THAT 500 MB LOW SHOULD LIFT OUT INTO NORTHEAST
WYOMING OR SOUTHEAST MONTANA BY SATURDAY EVENING.
THURSDAY...SHOWERS WILL LINGER AT LEAST IN THE MORNING...WITH
ISOLATED THUNDER POSSIBLE. CHANCES DECREASE THROUGH THE AFTERNOON.
EXPECT AT LEAST THE SOUTHWEST HALF OF OUR FORECAST AREA TO SEE
SOME AFTERNOON SUNSHINE AND THAT SHOULD HELP PUSH HIGHS INTO THE
70S THERE. AREAS FROM AROUND YANKTON DOWN TO ONAWA...HARLAN AND
RED OAK MAY ONLY TOP OUT FROM 65 TO 70. PCPN AMOUNTS THURSDAY ARE
EXPECTED TO BE MOSTLY UNDER 0.25 INCHES.
A WEAK COLD FRONT WILL SETTLE DOWN INTO THE FORECAST AREA THURSDAY
NIGHT AND THEN STALL. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG
AND NORTH OF THE BOUNDARY THURSDAY NIGHT AS THE LOW LEVEL JET
INCREASES AND CAUSES ISENTROPIC LIFT. BEST FOCUS SEEMS TO BE OVER
SOUTHEAST NEBRASKA.
FRIDAY AND FRIDAY NIGHT WILL BE INTERESTING. SOUTHERLY LOW LEVEL
FLOW INCREASES AS LOW PRESSURE INITIALLY OVER NORTHEAST COLORADO AT
12Z FRIDAY LIFTS NORTH TO WEST/NORTHWEST OF VALENTINE BY 06Z
SATURDAY. HIGHS FRIDAY SHOULD REACH 75 TO 80...PUSHING BOUNDARY
LAYER CAPE VALUES INTO THE 1500 TO 3000 J/KG RANGE. 0-6 KM AGL BULK
SHEAR VALUES SHOULD BE MOSTLY 25-40 KNOTS. STORMS MAY INITIALLY BE
MOSTLY NORTH OF THE FRONT...BUT THEN COULD ALSO DEVELOP IN THE WARM
SECTOR OR FARTHER BACK TO THE WEST IN CENTRAL NEBRASKA LATER IN THE
DAY. DETAILS SHOULD BECOME MORE CLEAR WITH THURSDAY MODEL RUNS ON
THE LOCATION OF FRONTAL BOUNDARIES WHICH WILL HELP FOCUS THE
ACTIVITY IN THE AFTERNOON AND EVENING. STORM COVERAGE MAY DROP OFF
DRASTICALLY AFTER MIDNIGHT.
SATURDAY...OVERALL PARAMETERS ARE EXPECTED TO BE IN PLACE FOR
ANOTHER POSSIBLE SEVERE EVENT...BUT NOT COMPLETELY SOLD ON THAT
SINCE IT WILL AT LEAST SOMEWHAT DEPEND ON WHAT HAPPENS FRIDAY. MID
LEVEL WINDS SHOULD INCREASE AND THEREFORE BULK SHEAR VALUES MAY
END UP HIGHER THAN THOSE FRIDAY. TIMING OF CONVECTION WILL BE THE
KEY.
MILLER
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
STORMS SHOULD LINGER INTO SATURDAY NIGHT...WITH SHOWERS/A FEW
EMBEDDED STORMS POSSIBLE SUNDAY MORNING. THE 12Z GFS WAS MOSTLY
DRY IN OUR AREA SUNDAY...BUT THE 12Z ECMWF WAS ABOUT 6 HOURS
SLOWER LIFTING PCPN OUT OF THE AREA. SO...FOR NOW WE HAVE KEPT
SOME LOW POPS SUNDAY IN OUR NORTHERN ZONES SUNDAY.
SUNDAY NIGHT THROUGH TUESDAY SHOULD BE LESS ACTIVE AS HIGH PRESSURE
BUILDS INTO THE REGION WITH COOL TEMPERATURES. SOME LOWS COULD DROP
DOWN TO NEAR 40. IT APPEARS THAT CHANCES FOR SHOWERS/STORMS WILL
INCREASE AGAIN BY TUESDAY NIGHT AND WEDNESDAY AS SHORTWAVE ENERGY
MOVES IN FROM THE WEST/SOUTHWEST.
MILLER
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1140 PM CDT WED MAY 13 2015
VSBYS/CIGS HAVE DROPPED TO MVFR WITH THE BAND OF RAIN THAT MOVED
ACROSS THE FORECAST AREAS THIS EVENING. THESE CONDITIONS WILL
CONTINUE THROUGH THURSDAY MORNING...HOWEVER...OBS/RAP13 SHOW THERE
IS AN AREA OF DRIER AIR THAT WILL AFFECT THE KOMA/KLNK WITH MORE
VARIABLE CONDITIONS...WHERE VFR CONDITIONS WILL BE POSSIBLE BEFORE
DROPPING BACK TO MVFR/IFR THROUGH 18-00Z. LOOK FOR IMPROVING
CONDITIONS WITH DECREASING CLOUDS FROM WEST TO EAST THURSDAY
AFTERNON.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE/MILLER
LONG TERM...MILLER
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
951 AM PDT THU MAY 14 2015
.SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED
THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN
AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS
FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME
SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT
ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY
NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES.
&&
.UPDATE...ONLY LINGERING LIGHT SHOWER ACTIVITY LEFT IN THE FAR
NORTHERN LAS VEGAS VALLEY AND THE SHEEP RANGE. MODELS BRING ANOTHER
ROUND OF SHOWERS TO THE VALLEY THIS AFTERNOON INTO THE EVENING
INCLUDING POSSIBLE THUNDERSTORMS.
VISIBLE SATELLITE SHOWS A BROAD DECK OF MID LEVEL CLOUDS OVER SAN
BERNARDINO COUNTY AND MOHAVE COUNTY SPREADING NORTH AND PARTLY TO
MOSTLY CLOUDY CONDITIONS ARE EXPECTED THROUGH THE DAY WHICH WILL
LIKELY LIMIT DAYTIME HEATING IN MOST AREAS. SCATTERED SHOWERS AND
ISOLATED STORMS ARE EXPECTED TODAY AS SHORTWAVE ENERGY AHEAD OF LOW
PRESSURE OFF THE WEST COAST EJECTS INLAND ACROSS THE CWA. -SALMEN-&&
.AVIATION... FOR MCCARRAN...A DENSE BAND OF MID LEVEL CLOUDS ARE
SPREADING ACROSS THE VALLEY AND BKN CLOUDS GENERALLY AOA 15K FEET
ARE EXPECTED BEFORE SHOWERS REDEVELOP THIS AFTERNOON. SOUTH WINDS OF
15-25KT TO CONTINUE WITH GUSTS TO 30KTS POSSIBLE. SOME VARIABILITY
IN WIND SPEED/DIRECTION POSSIBLE WHEN SHOWERS MOVE THROUGH THE
VALLEY LATER THIS AFTERNOON. CIGS IN THE 8-10K FT RANGE THIS IS
EXPECTED LATER THIS AFTERNOON AND EVENING WITH LOW CIGS POSSIBLE IN
RAIN. -SALMEN-
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD
DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY
IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE
SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES
FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL
RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE.
BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED.
&&
.PREV UPDATE...809 AM PDT...A QUICK UPDATE TO ADD SHOWERS/STORMS TO
PORTIONS OF CLARK COUNTY INCLUDING THE LV VALLEY UP THROUGH LINCOLN
COUNTY BASED ON LATEST RADAR TRENDS AND LIGHTNING DATA. -SALMEN-
&&
.PREVIOUS DISCUSSION...256 AM PDT...
.SHORT TERM...THROUGH SATURDAY NIGHT.
THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE
FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER
STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION
IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT
ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH
MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS
THE MOJAVE DESERT.
WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE
OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE
REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL
BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET
WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON.
WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE...
BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL
SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST
FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY
EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS
AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY
CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL
GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH.
WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A
WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD
OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE
OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST
ANY WIND HEADLINES.
BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS
HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING
A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH
OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY
MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN
MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART
OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER
AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO
LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL
SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND
RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY
SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH.
FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY
DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS
AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER
TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL
AVERAGES.
ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND
MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS
ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN
ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY
BUT STILL BE AROUND 15 DEGREES BELOW NORMAL.
.LONG TERM...SUNDAY THROUGH THURSDAY.
SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF
THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD
OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH
ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING
AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND
INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES
TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST
TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO
SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING
ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE
EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING
DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON.
THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY
LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH
THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT
THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE
SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY
WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL
THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS
OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS
LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE
UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES. &&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
809 AM PDT THU MAY 14 2015
.SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED
THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN
AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS
FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME
SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT
ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY
NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES.
&&
.UPDATE...A QUICK UPDATE TO ADD SHOWERS/STORMS TO PORTIONS OF CLARK
COUNTY INCLUDING THE LV VALLEY UP THROUGH LINCOLN COUNTY BASED ON
LATEST RADAR TRENDS AND LIGHTNING DATA. -SALMEN-&&
.PREVIOUS DISCUSSION...256 AM PDT...
.SHORT TERM...THROUGH SATURDAY NIGHT.
THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE
FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER
STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION
IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT
ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH
MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS
THE MOJAVE DESERT.
WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE
OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE
REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL
BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET
WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON.
WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE...
BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL
SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST
FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY
EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS
AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY
CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL
GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH.
WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A
WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD
OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE
OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST
ANY WIND HEADLINES.
BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS
HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING
A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH
OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY
MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN
MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART
OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER
AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO
LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL
SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND
RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY
SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH.
FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY
DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS
AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER
TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL
AVERAGES.
ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND
MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS
ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN
ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY
BUT STILL BE AROUND 15 DEGREES BELOW NORMAL.
.LONG TERM...SUNDAY THROUGH THURSDAY.
SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF
THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD
OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH
ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING
AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND
INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES
TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST
TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO
SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING
ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE
EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING
DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON.
THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY
LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH
THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT
THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE
SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY
WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL
THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS
OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS
LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE
UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND.
&&
.AVIATION... FOR MCCARRAN...INCREASING CLOUDS AND LOWERING CEILINGS
EXPECTED TODAY AS A PACIFIC STORM IMPACTS THE REGION. SOUTH WINDS OF
15-25KT EXPECTED WITH GUSTS TO 30KTS BUT SOME VARIABILITY POSSIBLE
WHILE SHOWERS MOVE THROUGH THE VALLEY IN THE LATE AFTERNOON. CIGS
FALLING IN THE 8-10K FT RANGE THIS AFTERNOON AND EVENING. ADDITIONAL
RAIN AND REDUCED CIGS POSSIBLE FRIDAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD
DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY
IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE
SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES
FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL
RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE.
BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
256 AM PDT THU MAY 14 2015
.SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED
THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN
AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS
FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME
SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT
ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY
NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES.
&&
.SHORT TERM...THROUGH SATURDAY NIGHT.
THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE
FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER
STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION
IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT
ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH
MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS
THE MOJAVE DESERT.
WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE
OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE
REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL
BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET
WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON.
WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE...
BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL
SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST
FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY
EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS
AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY
CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL
GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH.
WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A
WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD
OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE
OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST
ANY WIND HEADLINES.
BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS
HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING
A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH
OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY
MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN
MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART
OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER
AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO
LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL
SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND
RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY
SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH.
FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY
DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS
AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER
TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL
AVERAGES.
ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND
MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS
ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN
ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY
BUT STILL BE AROUND 15 DEGREES BELOW NORMAL.
.LONG TERM...SUNDAY THROUGH THURSDAY.
SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF
THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD
OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH
ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING
AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND
INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES
TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST
TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO
SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING
ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE
EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING
DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON.
THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY
LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH
THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT
THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE
SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY
WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL
THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS
OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS
LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE
UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND.
&&
.AVIATION... FOR MCCARRAN...INCREASING CLOUDS AND LOWERING CEILINGS
EXPECTED TODAY AS A PACIFIC STORM IMPACTS THE REGION. SOUTH WINDS OF
15-25KT EXPECTED WITH GUSTS TO 30KTS BUT SOME VARIABILITY POSSIBLE
WHILE SHOWERS MOVE THROUGH THE VALLEY IN THE LATE AFTERNOON. CIGS
FALLING IN THE 8-10K FT RANGE THIS AFTERNOON AND EVENING. ADDITIONAL
RAIN AND REDUCED CIGS POSSIBLE FRIDAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD
DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY
IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE
SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES
FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL
RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE.
BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1155 AM MDT THU MAY 14 2015
.AVIATION...
18Z TAF CYCLE
ISOLD SH/TS WILL IMPACT NW/NC AND PERHAPS EASTERN PORTIONS OF THE
FORECAST AREA THROUGH THE EARLY/MID EVENING HRS. LIKELY IMPACTS
WOULD BE TO FMN/LVS WITH POSSIBLE IMPACTS TO GUP/TCC. THE IMPACTS
ARE NOT EXPECTED TO BE TOO SIGNIFICANT OTHER THAN TO FMN WHERE A
TEMPO TS IS USED. WILL MONITOR THAT TREND BECAUSE MAYBE TOO
BULLISH WITH THAT SCENARIO. THE NEXT ROUND OF SH SHOULD NOT
SIGNIFICANTLY IMPACT TERMINAL SITES UNTIL AFTER 18Z FRI. WIND FLOW
WILL INCREASE AND ABQ COULD EXPERIENCE PERIODIC GUSTS NEAR 35 KT
LATER THIS AFTERNOON. UNSURE ABOUT AN AWW AT THIS TIME. WILL BE
SOMEWHAT DEPENDENT ON CLEARING CLOUD COVER. OTHER SITES WILL SEE
GUSTS BETWEEN 30-35 KT AT TIMES...GUP/AEG AND LVS. LVS/GUP SHOULD
EXPERIENCE THE HIGHEST WIND VALUES THIS AFTERNOON AND CANT RULE
OUT HIGHER GUSTS. MTN TOP OBSCD WILL BE THE MAIN IMPACTS DUE TO
PASSING SHOWERS ACROSS THE NORTH.
50
&&
.PREV DISCUSSION...330 AM MDT THU MAY 14 2015...
.SYNOPSIS...
ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE.
SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND
WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS
BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY
AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST
NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY
THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY.
&&
.DISCUSSION...
WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO
AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS
VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH
AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS
MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS
MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT.
SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR
TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD
DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7
WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS
THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE
WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE
HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW
AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH
SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE
THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT
BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY.
&&
.FIRE WEATHER...
A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL
TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF
NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY
ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT
MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL
PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO
SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER
ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN
HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME
INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE
EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS
FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER
THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY
ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT
WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH
GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY
STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT
VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY
SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT
WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR
LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH
AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY...
PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA.
STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH
OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH.
BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE
STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH
AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD
ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS...
MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO
SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE
CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE
FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE
BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT
COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED.
ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT
LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT
WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP
COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE
FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
605 AM MDT THU MAY 14 2015
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS TO CONTINUE TO BE THE RULE THROUGH THE 12Z FRI...
BUT THERE WILL BE A FEW EXCEPTIONS. ONE WILL BE ACROSS FAR EAST
CENTRAL NM NEAR THE TX STATE LINE WHERE IFR AND POSS LIFR CIGS
WILL BE A POSSIBILITY TIL ABOUT 16Z TODAY AND THEN AFTER ROUGHLY
09Z FRI ACROSS AREAS MAINLY SOUTH OF INTERSTATE 40 AND FROM THE
PECOS RIVER VALLEY ON EAST. OTHERWISE...S TO SW LOW LEVEL FLOW TO
INCREASE LATE THIS MORN AND AFTN. HIGHEST TERMINAL FCST GUSTS
LIKELY TO BE AT KLVS THIS AFTN...IN THE VCNTY OF 34 TO 36KTS. A
FEW HIGH BASED AND GUSTY -SHRA AND -TSRA ACROSS NORTH AND FAR WEST
NM MAY IMPACT KFMN AND KGUP BETWEEN ABOUT 20Z AND 02Z. A LOWER
CHANCE FOR ISOLD TSRA ARE POSSIBLE LATE TODAY AS WELL...MAINLY
NEAR THE TX LINE...POSS IMPACTING KTCC.
43
&&
.PREV DISCUSSION...330 AM MDT THU MAY 14 2015...
.SYNOPSIS...
ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE.
SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND
WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS
BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY
AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST
NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY
THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY.
&&
.DISCUSSION...
WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO
AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS
VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH
AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS
MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS
MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT.
SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR
TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD
DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7
WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS
THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE
WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE
HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW
AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH
SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE
THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT
BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY.
&&
.FIRE WEATHER...
A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL
TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF
NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY
ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT
MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL
PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO
SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER
ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN
HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME
INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE
EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS
FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER
THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY
ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT
WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH
GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY
STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT
VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY
SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT
WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR
LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH
AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY...
PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA.
STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH
OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH.
BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE
STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH
AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD
ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS...
MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO
SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE
CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE
FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE
BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT
COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED.
ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT
LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT
WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP
COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE
FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
330 AM MDT THU MAY 14 2015
.SYNOPSIS...
ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE.
SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND
WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS
BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY
AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST
NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY
THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY.
&&
.DISCUSSION...
WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO
AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS
VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH
AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS
MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS
MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT.
SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR
TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD
DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7
WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS
THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE
WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE
HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW
AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH
SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE
THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT
BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY.
&&
.FIRE WEATHER...
A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL
TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF
NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY
ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT
MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL
PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO
SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER
ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN
HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME
INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE
EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS
FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER
THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY
ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT
WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH
GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY
STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT
VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY
SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT
WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR
LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH
AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY...
PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA.
STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH
OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH.
BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE
STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH
AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD
ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS...
MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO
SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE
CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE
FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE
BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT
COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED.
ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT
LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT
WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP
COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE
FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD.
43
&&
.AVIATION...
06Z TAF CYCLE
VFR CONDITIONS TO PERSIST AT AREA TERMINALS...EXCEPT AT KROW WHERE
IFR VSBYS IN FOG ARE POSSIBLE EARLY THURSDAY MORNING. SOME POTENTIAL
FOR FOG DEVELOPMENT AT KTCC AS WELL...BUT FORECASTER CONFIDENCE
TOO LOW TO INCLUDE IN TAF. OTHERWISE...LOOK FOR INCREASING
SOUTHWEST LOW LEVEL FLOW THURSDAY WITH WINDY CONDITIONS BY
AFTERNOON. HIGHEST GUSTS FORECAST AT KLVS THURSDAY AFTERNOON
AROUND 36-38KTS. HIGH-BASED SHOWERS LIKELY NORTH WITH GUSTY WINDS
MAY IMPACT KFMN AND KGUP LATE DAY. A FEW THUNDERSTORMS ARE
POSSIBLE LATE DAY AS WELL...MAINLY NEAR THE TEXAS BORDER AND ACROSS
THE NORTHEAST QUARTER...POSSIBLY IMPACTING KTCC.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 74 44 61 41 / 20 30 30 50
DULCE........................... 69 40 57 35 / 30 30 40 70
CUBA............................ 70 43 59 35 / 20 10 40 60
GALLUP.......................... 71 38 59 35 / 10 10 30 50
EL MORRO........................ 66 36 56 35 / 5 10 30 60
GRANTS.......................... 71 38 61 33 / 5 10 30 40
QUEMADO......................... 68 37 60 38 / 5 10 20 50
GLENWOOD........................ 78 42 68 43 / 5 10 20 30
CHAMA........................... 64 33 53 31 / 30 30 40 70
LOS ALAMOS...................... 67 46 61 39 / 10 10 30 40
PECOS........................... 66 40 60 38 / 10 10 20 30
CERRO/QUESTA.................... 68 36 60 35 / 20 20 20 40
RED RIVER....................... 60 34 55 30 / 30 20 20 40
ANGEL FIRE...................... 61 35 56 30 / 20 20 20 40
TAOS............................ 68 38 61 35 / 20 10 20 40
MORA............................ 65 39 60 37 / 20 10 20 30
ESPANOLA........................ 73 40 65 43 / 10 10 20 30
SANTA FE........................ 70 39 62 40 / 10 10 20 40
SANTA FE AIRPORT................ 73 41 64 37 / 10 10 20 30
ALBUQUERQUE FOOTHILLS........... 74 44 64 46 / 10 10 20 30
ALBUQUERQUE HEIGHTS............. 77 49 67 44 / 5 5 20 20
ALBUQUERQUE VALLEY.............. 78 44 69 45 / 5 5 20 20
ALBUQUERQUE WEST MESA........... 77 45 69 44 / 10 5 20 20
LOS LUNAS....................... 77 47 71 42 / 5 5 20 20
RIO RANCHO...................... 77 48 68 44 / 10 5 20 30
SOCORRO......................... 79 50 73 46 / 5 10 10 10
SANDIA PARK/CEDAR CREST......... 71 43 66 39 / 10 10 20 30
TIJERAS......................... 73 43 68 42 / 10 10 20 30
MORIARTY/ESTANCIA............... 74 40 65 36 / 10 10 20 30
CLINES CORNERS.................. 70 42 64 37 / 10 10 20 30
GRAN QUIVIRA.................... 72 44 67 42 / 5 10 20 20
CARRIZOZO....................... 77 48 72 49 / 5 20 10 20
RUIDOSO......................... 73 47 69 41 / 10 20 10 30
CAPULIN......................... 74 43 67 42 / 5 20 5 20
RATON........................... 75 42 70 39 / 10 20 10 20
SPRINGER........................ 73 41 68 41 / 10 20 10 20
LAS VEGAS....................... 70 40 65 38 / 10 10 10 20
CLAYTON......................... 79 49 76 48 / 5 20 5 20
ROY............................. 76 47 71 44 / 10 20 10 20
CONCHAS......................... 77 49 76 51 / 10 10 5 20
SANTA ROSA...................... 80 50 78 47 / 10 10 5 20
TUCUMCARI....................... 84 53 81 51 / 10 20 5 20
CLOVIS.......................... 82 52 77 51 / 10 20 10 30
PORTALES........................ 84 53 79 55 / 10 20 10 40
FORT SUMNER..................... 84 52 80 51 / 10 20 5 20
ROSWELL......................... 86 54 83 52 / 10 20 5 30
PICACHO......................... 78 52 79 50 / 10 20 5 20
ELK............................. 72 51 73 48 / 10 20 10 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
958 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 946 PM CDT FRI MAY 15 2015
MAIN UPDATE TO THE FORECAST THIS EVENING WAS TO SPREAD THE
POSSIBILITY OF ISOLATED THUNDERSTORMS INTO THE WESTERN PART OF THE
STATE. FORECAST MUCAPE FROM THE RAP SHOWS WEAK INSTABILITY FROM
WESTERN INTO SOUTH CENTRAL NORTH DAKOTA OVERNIGHT. CURRENT RADAR
MOSAIC INDICATES SHOWERS AND THUNDERSTORMS IN WESTERN SOUTH DAKOTA
CONTINUE TO MOVE NORTH...WHICH IS WELL COVERED IN THE FORECAST
WITH HIGH POPS IN PLACE OVERNIGHT. DECIDED TO ISSUE THE SPECIAL
WEATHER STATEMENT (SPS) AGAIN TO HIGHLIGHT THE ACTIVE WEATHER IN
THE FORECAST FOR THIS WEEKEND.
UPDATE ISSUED AT 645 PM CDT FRI MAY 15 2015
REGIONAL RADAR MOSAIC SHOWERS A FEW LIGHT SHOWERS MOVING ACROSS
WESTERN NORTH DAKOTA INTO EASTERN MONTANA. FARTHER
SOUTH...THUNDERSTORMS WERE LIFTING NORTH ACROSS PARTS OF WESTERN
SOUTH DAKOTA. THE LATEST HRRR AND RAP SUGGEST IT WILL TAKE A
FEW MORE HOURS BEFORE THE MAIN AREA OF RAIN IN SOUTH DAKOTA
REACHES THE SOUTHWEST PART OF THE STATE. THE HRRR ALSO SUGGESTS
THERE COULD BE A FEW ISOLATED SHOWERS IN ADVANCE OF THE MAIN AREA
OF RAIN...SO DID NOT REMOVE POPS ALTOGETHER IN THE NEAR TERM...BUT
DID DECREASE THEM TO SOME DEGREE EARLY THIS EVENING. MADE MINOR
ADJUSTMENTS TO SKY COVER AND TEMPERATURES...BUT OVERALL THE
REMAINDER OF THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
MAIN ISSUES IN THE SHORT TERM ARE TIMING THE START OF
PRECIPITATION THIS EVENING AND POSSIBLE SEVERE THUNDERSTORMS
SATURDAY. MODELS AND RADAR SHOWING SLOWER TRENDS OF PRECIPITATION SO
WILL DELAY THE ONSET OF PRECIP ACROSS THE SOUTH CENTRAL AND JAMES
RIVER VALLEY TO MID TO LATE EVENING. NAM/GFS BOTH HAVE A FAIRLY
GOOD CAP LOWER LEVELS. THERE IS SOME ELEVATED CAPE THIS EVENING AND
OVERNIGHT SO REFINED THE THREAT OF NON SEVERE THUNDERSTORMS
TONIGHT TO JUST THE SOUTH CENTRAL AND AFTER 9 PM CDT. ON SATURDAY
LOOKING FRO A MORE SIGNIFICANT SHORTWAVE TROUGH SUPPORTING
THUNDERSTORMS. BEST CAPE REMAINS SOUTH CENTRAL WITH THE JAMES
RIVER VALLEY MORE CAPPED TRENDING TO TALL SKINNY CAPE BY EVENING.
THIS WOULD LEND LESS SUPPORT TO SEVERE MORE TO MODERATE RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
VERY ACTIVE WEATHER WILL OCCUR OVER THE WEEKEND WITH NUMEROUS
IMPACTS AS A STRONG STORM SYSTEM CROSSES THE NORTHERN PLAINS.
INITIALLY...SEVERE THUNDERSTORMS WILL BE THE THREAT SATURDAY
EVENING...THOUGH SURFACE BASED INSTABILITY WILL DIMINISH WHILE
PROFILES SATURATE PER FORECAST SOUNDINGS. MEANWHILE A STRONG 100KT
JET WILL BEGIN NOSING INTO THE DAKOTAS AND HELP DEEPEN THE CUT OFF
UPPER LOW WHICH IS LOCATED OVER SOUTH DAKOTA AT 12Z SUNDAY.
DEEP SURFACE LOW REACHES SOUTHEASTERN NORTH DAKOTA BY 00Z MON WITH
STRONG SURFACE PRESSURE GRADIENT ACROSS THE STATE...26MB CHANGE FROM
NORTHWEST ND TO THE SOUTHEAST PART OF THE STATE PER GFS. SUB-
FREEZING 850MB TEMPS DROP SOUTHWARD INTO CENTRAL NORTH DAKOTA...WITH
SOUNDINGS SUPPORTING A CHANGEOVER OF RAIN TO SNOW LATE SUNDAY/SUNDAY
NIGHT. WPC WINTER WEATHER DESK SHOWS AMOUNTS AROUND 2-4 INCHES
ACROSS THE NORTH. TRAVEL COULD BECOME HAZARDOUS IN SOME AREAS WITH
COMBINATION OF STRONG WIND AND SNOW. BY MID-DAY MONDAY THE LOW
CENTER REACHES THE GREAT LAKES WITH HIGH PRESSURE BUILDING ACROSS
THE STATE. MAX TEMPS WILL GRADUALLY MODERATE TO THE 50S AND 60S BY
WED/THU.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 645 PM CDT FRI MAY 15 2015
THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE
ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN ACROSS SOUTH
DAKOTA WILL LIFT NORTH BRINING A CHANCE OF SHOWERS AND PERHAPS A
FEW THUNDERSTORMS TO THE TERMINALS LATE TONIGHT INTO SATURDAY
MORNING. CEILINGS WILL LOWER AS THE RAIN MOVES INTO THE REGION.
THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH
TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE
SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN
SATURDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 303 PM CDT FRI MAY 15 2015
ENSEMBLE SITUATIONAL AWARENESS TABLE SHOWS PRECIPITABLE WATER
OVER OUR AREA AROUND 90TH PERCENTILE FROM SATURDAY INTO SUNDAY
AFTERNOON. FORECAST PRECIP AMOUNTS THROUGH 00Z MONDAY RANGE FROM
AROUND 0.75 INCHES OVER SOUTHWESTERN ND TO 2+ INCHES...MAINLY
NORTH AND EAST. CONTEMPLATED AN AREAL FLOOD WATCH...BUT THE
HEAVIEST QPF AMOUNTS WITH THIS STORM ARE GENERALLY NORTH AND EAST
OF THE AREAS THAT HAVE RECEIVED THE HEAVIEST PRECIPITATION OVER
THE PAST COUPLE WEEKS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...WAA
LONG TERM...JNS
AVIATION...CK
HYDROLOGY...WAA/JNS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
949 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 949 PM CDT FRI MAY 15 2015
MADE A FEW MINOR TWEAKS TO POPS. HRRR AND A FEW OTHER HIGH RES
MODELS HAVE SOME SHOWERS MOVING INTO THE FAR SOUTHERN CWA AND THEN
DISSIPATING TONIGHT...BUT THE NAM AND RAP DO NOT HAVE MUCH AT ALL
OVERNIGHT. WITH SOME 850MB WARM AIR ADVECTION EXPECTED TO KICK IN
WILL KEEP SOME POPS GOING FOR THE FAR SOUTH AND WEST...ALTHOUGH
THE LOW LEVEL JET AND THE MAIN PRECIP COMPLEX WILL REMAIN OVER
THE WESTERN DAKOTAS. THE EARLY MORNING PRECIP WILL DISSIPATE AND
THEN IT SEEMS THAT WE WILL NOT HAVE MUCH UNTIL LATER ON
SATURDAY...BUT KEPT SOME POPS GOING TO BLEND WITH NEIGHBORS.
UPDATE ISSUED AT 646 PM CDT FRI MAY 15 2015
MADE A FEW MINOR TWEAKS TO CLOUDS...BUT NO OTHER CHANGES TO THE
GOING FORECAST. ANY PRECIP WILL NOT ARRIVE UNTIL AFTER MIDNIGHT AT
THE EARLIEST.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 332 PM CDT FRI MAY 15 2015
CONCERNS WILL BE THUNDER CHANCES AND SEVERE POTENTIAL. THE OVERALL
MODEL TRENDS ARE FOR A SLOWER EVOLUTION OF THIS SYSTEM...AND ALL
FORECAST CHANGES REFLECT THIS TREND. THERE WILL LIKELY BE SEVERAL
WAVES OF PRECIP THAT MOVE THROUGH THE REGION DURING THIS PERIOD.
THE BEST CHANCES FOR TONIGHT (LIKELY AFTER MIDNIGHT) INTO SATURDAY
MORNING WILL BE WEST OF THE VALLEY. AS THE ENTIRE UPPER TROUGH
SLOWLY PROPAGATES EAST...THE BETTER PRECIP CHANCES ALSO MOVE EAST.
850MB FLOW WILL BE DUE SOUTH FROM THE GULF OF MEXICO BY SATURDAY
AFTERNOON. THIS WILL TRANSPORT A MOIST AIRMASS WHICH SHOULD
PROMOTE WEAK TO MODERATE INSTABILITY SAT AFTERNOON. IT DOES APPEAR
THAT CLOUD COVER/HEATING MAY BE AN ISSUE...WITH FOCUSED FORCING
AND STRONGEST DEEP LAYER SHEAR REMAINING WEST OF THE REGION. WITH
THAT SAID...DO ANTICIPATE AT LEAST SOME STRONGER STORMS SAT
AFTERNOON/EVENING...AND SPC CONTINUES TO INDICATE THE SLIGHT RISK.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 332 PM CDT FRI MAY 15 2015
SUNDAY-MONDAY...CONCERNS WILL BE EXCESSIVE RAINFALL
POTENTIAL...AND WINTER WEATHER POTENTIAL. UPPER LOW STRENGTHENS
AND PROPAGATES THROUGH THE REGION. ANTICIPATE PERIODIC SHOWERS
AND THUNDER IN THE WARM SECTOR OF THIS SYSTEM...WITH MORE
WIDESPREAD RAINFALL WITHIN THE DEFORMATION ZONE AREA. ALTHOUGH THE
EXACT TRACK OF THIS SYSTEM IS STILL A BIT UNCLEAR...WHAT IS CLEAR
THAT AN AREA OF 2-3 INCHES QPF LIKELY IN THIS DEFORMATION ZONE
AREA (GIVEN STRENGTH OF THE FORCING COMBINED WITH HIGH PWATS).
CURRENT SIGNALS SUGGEST THE MOST LIKELY AREA WILL BE THE DEVILS
LAKE BASIN INTO THE NORTHERN VALLEY. THIS AREA IS NORTH OF AREAS
THAT HAVE RECEIVED HEAVIER RAINFALL OVER THE PAST COUPLE
WEEKS...SO FLOODING CONCERNS REMAIN MINIMAL.
THE ACTUAL STRENGTH OF THIS SYSTEM WILL DETERMINE WINTER WEATHER
POTENTIAL. THE STRONGER ECMWF AND NAM GENERATE ENOUGH
EVAPORATIONAL COOLING TO SUGGEST THAT THE AIRMASS WILL BE NEAR 32F
AT THE SFC...AND IF THE PRECIP RATES ARE STRONG ENOUGH
ACCUMULATING SNOWFALL WILL BE POSSIBLE. MOST LIKELY AREA WILL BE
THE DEVILS LAKE BASIN...LATER SUN AFTERNOON INTO SUN NIGHT. WITH
STRONG WINDS EXPECTED (LIKELY ADVISORY CRITERIA)...FALLING SNOW
COMBINED WITH THE WIND COULD CAUSE SIGNIFICANT TRAVEL ISSUES.
CONSIDERING THE TIME OF YEAR AND THAT MODELS ARE NOT IN PERFECT
AGREEMENT...WITH DOWNPLAY THIS POTENTIAL UNTIL MORE CONFIDENCE CAN
BE OBTAINED.
STRONG WINDS CONTINUE INTO MONDAY.
TUESDAY-FRIDAY...THE MEAN WESTERN CONUS TROF REMAINS INTACT
THROUGH THE EXTENDED PERIOD BUT THE NORTHERN PLAINS STAYS
RELATIVELY DRY AND QUIET. BOTH THE ECMWF AND THE GFS DEPICT A
RATHER STOUT /1030+/ STOUT SURFACE HIGH PRESSURE AREA DROPPING
INTO THE NORTHERN PLAINS...IN THE WAKE OF THE LARGE DEPARTING
STORM SYSTEM WITH A CORRESPONDING BUT WEAK H5 SHORTWAVE RIDGE
ALOFT. THIS SHOULD RESULT IN GENLY FAIR SKIES AND LIGHT WINDS...
BUT SOMEWHAT COOLER THAT NORMAL TEMPERATURES TUES INTO WED. MODELS
DIVERGE A BIT WED AND THURS WITH THE GFS PUSHING A BIT MORE MOIST
FLOW INTO SOUTHERN ND WHILE THE ECMWF KEEP A BIT DRIER. AS IT
IS...HAVE INTRODUCED SCT SHOWERS INTO OUR FAR SOUTHWESTERN
COUNTIES FOR WED...BUT OTHERWISE REMAIN DRY THE REST OF THE
PERIOD. SOUTHERLY RETURN FLOW EVENTUALLY DEVELOPS FROM THURS INTO
FRI...TEMPERATURES INCREASING TOWARDS SEASONABLE NORMALS BY FRI.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 646 PM CDT FRI MAY 15 2015
SOME CIGS AROUND 3500-4000 FT HANGING AROUND KFAR AND KBJI...BUT
THE REST OF THE FORECAST AREA HAS MAINLY HIGH CLOUDS AND LIGHT AND
VARIABLE WINDS. CLOUDS INCREASE AGAIN THROUGHOUT THE NIGHT AND
INTO TOMORROW...BUT THINK THAT CIGS WILL REMAIN VFR LEVEL. SHORT
RANGE MODELS ARE SLOWER IN BRINGING PRECIP INTO THE FORECAST AREA...WITH
THE ACTIVITY MOVING UP OUT OF SOUTH DAKOTA DISSIPATING BEFORE IT
REACHES THE TAF SITES TOMORROW MORNING. THINK THE BEST CHANCES FOR
PRECIP FURTHER NORTH AND EAST WILL BE IN THE AFTERNOON...SO WILL
KEEP THE VCTS MENTION UNTIL LATER ON IN THE DAY. LIGHT AND
VARIABLE WINDS WILL INCREASE OUT OF THE SOUTHEAST BY SATURDAY
AFTERNOON AT 15 KTS OR SO.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/GUST
AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
645 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 645 PM CDT FRI MAY 15 2015
REGIONAL RADAR MOSAIC SHOWERS A FEW LIGHT SHOWERS MOVING ACROSS
WESTERN NORTH DAKOTA INTO EASTERN MONTANA. FARTHER
SOUTH...THUNDERSTORMS WERE LIFTING NORTH ACROSS PARTS OF WESTERN
SOUTH DAKOTA. THE LATEST HRRR AND RAP SUGGEST IT WILL TAKE A
FEW MORE HOURS BEFORE THE MAIN AREA OF RAIN IN SOUTH DAKOTA
REACHES THE SOUTHWEST PART OF THE STATE. THE HRRR ALSO SUGGESTS
THERE COULD BE A FEW ISOLATED SHOWERS IN ADVANCE OF THE MAIN AREA
OF RAIN...SO DID NOT REMOVE POPS ALTOGETHER IN THE NEAR TERM...BUT
DID DECREASE THEM TO SOME DEGREE EARLY THIS EVENING. MADE MINOR
ADJUSTMENTS TO SKY COVER AND TEMPERATURES...BUT OVERALL THE
REMAINDER OF THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
MAIN ISSUES IN THE SHORT TERM ARE TIMING THE START OF
PRECIPITATION THIS EVENING AND POSSIBLE SEVERE THUNDERSTORMS
SATURDAY. MODELS AND RADAR SHOWING SLOWER TRENDS OF PRECIPITATION SO
WILL DELAY THE ONSET OF PRECIP ACROSS THE SOUTH CENTRAL AND JAMES
RIVER VALLEY TO MID TO LATE EVENING. NAM/GFS BOTH HAVE A FAIRLY
GOOD CAP LOWER LEVELS. THERE IS SOME ELEVATED CAPE THIS EVENING AND
OVERNIGHT SO REFINED THE THREAT OF NON SEVERE THUNDERSTORMS
TONIGHT TO JUST THE SOUTH CENTRAL AND AFTER 9 PM CDT. ON SATURDAY
LOOKING FRO A MORE SIGNIFICANT SHORTWAVE TROUGH SUPPORTING
THUNDERSTORMS. BEST CAPE REMAINS SOUTH CENTRAL WITH THE JAMES
RIVER VALLEY MORE CAPPED TRENDING TO TALL SKINNY CAPE BY EVENING.
THIS WOULD LEND LESS SUPPORT TO SEVERE MORE TO MODERATE RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
VERY ACTIVE WEATHER WILL OCCUR OVER THE WEEKEND WITH NUMEROUS
IMPACTS AS A STRONG STORM SYSTEM CROSSES THE NORTHERN PLAINS.
INITIALLY...SEVERE THUNDERSTORMS WILL BE THE THREAT SATURDAY
EVENING...THOUGH SURFACE BASED INSTABILITY WILL DIMINISH WHILE
PROFILES SATURATE PER FORECAST SOUNDINGS. MEANWHILE A STRONG 100KT
JET WILL BEGIN NOSING INTO THE DAKOTAS AND HELP DEEPEN THE CUT OFF
UPPER LOW WHICH IS LOCATED OVER SOUTH DAKOTA AT 12Z SUNDAY.
DEEP SURFACE LOW REACHES SOUTHEASTERN NORTH DAKOTA BY 00Z MON WITH
STRONG SURFACE PRESSURE GRADIENT ACROSS THE STATE...26MB CHANGE FROM
NORTHWEST ND TO THE SOUTHEAST PART OF THE STATE PER GFS. SUB-
FREEZING 850MB TEMPS DROP SOUTHWARD INTO CENTRAL NORTH DAKOTA...WITH
SOUNDINGS SUPPORTING A CHANGEOVER OF RAIN TO SNOW LATE SUNDAY/SUNDAY
NIGHT. WPC WINTER WEATHER DESK SHOWS AMOUNTS AROUND 2-4 INCHES
ACROSS THE NORTH. TRAVEL COULD BECOME HAZARDOUS IN SOME AREAS WITH
COMBINATION OF STRONG WIND AND SNOW. BY MID-DAY MONDAY THE LOW
CENTER REACHES THE GREAT LAKES WITH HIGH PRESSURE BUILDING ACROSS
THE STATE. MAX TEMPS WILL GRADUALLY MODERATE TO THE 50S AND 60S BY
WED/THU.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 645 PM CDT FRI MAY 15 2015
THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE
ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN ACROSS SOUTH
DAKOTA WILL LIFT NORTH BRINING A CHANCE OF SHOWERS AND PERHAPS A
FEW THUNDERSTORMS TO THE TERMINALS LATE TONIGHT INTO SATURDAY
MORNING. CEILINGS WILL LOWER AS THE RAIN MOVES INTO THE REGION.
THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH
TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE
SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN
SATURDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 303 PM CDT FRI MAY 15 2015
ENSEMBLE SITUATIONAL AWARENESS TABLE SHOWS PRECIPITABLE WATER
OVER OUR AREA AROUND 90TH PERCENTILE FROM SATURDAY INTO SUNDAY
AFTERNOON. FORECAST PRECIP AMOUNTS THROUGH 00Z MONDAY RANGE FROM
AROUND 0.75 INCHES OVER SOUTHWESTERN ND TO 2+ INCHES...MAINLY
NORTH AND EAST. CONTEMPLATED AN AREAL FLOOD WATCH...BUT THE
HEAVIEST QPF AMOUNTS WITH THIS STORM ARE GENERALLY NORTH AND EAST
OF THE AREAS THAT HAVE RECEIVED THE HEAVIEST PRECIPITATION OVER
THE PAST COUPLE WEEKS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...WAA
LONG TERM...JNS
AVIATION...CK
HYDROLOGY...WAA/JNS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
141 PM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 142 PM CDT THU MAY 14 2015
MAIN UPDATE WAS TO SKY AND TEMPERATURES. LOW STRATUS PERSISTING
ACROSS THE WEST. LAST FEW RUNS OF THE HRRR STILL TRENDS MOSTLY
SUNNY...JUST WILL BE A BIT LATER THAN PREVIOUSLY THOUGHT. THIS
IMPACTED DAYTIME HIGHS ACROSS THE WEST...LOWERING A FEW DEGREES.
UPDATE
ISSUED AT 1029 AM CDT THU MAY 14 2015
SURFACE LOW PRESSURE CENTERED OVER WESTERN NEBRASKA WITH A QUASI-
STATIONARY SURFACE FRONT EXTENDING FROM THE LOW NORTH-NORTHEAST
ACROSS THE CENTRAL DAKOTAS INTO NORTHEASTERN NORTH DAKOTA. STRONG
MID LEVEL S/WV TROUGH LIFTING ACROSS THE EASTERN DAKOTAS TOWARDS
THE UPPER MISSISSIPPI VALLEY REGION. SHOWERS...SOME AREAS
MODERATE...CONTINUE ALONG THE FRONTAL ZONE ACROSS SOUTH CENTRAL
NORTH DAKOTA INTO NORTHEASTERN NORTH DAKOTA THIS MORNING. RAINFALL
AMOUNTS WITHIN THE BAND HAVE GENERALLY BEEN IN THE RANGE OF
0.5-0.75"...WITH AMOUNTS IN EARLIER CONVECTIVE BANDS IN EXCESS OF
AN INCH.
SHOWERS WILL CONTINUE TO SLOWLY LIFT NORTH AND EAST AS THE DAY
PROGRESSES...AND SHOULD BE ENTIRELY OUT OF MY EASTERN COUNTIES BY
03Z.
OTHER UPDATE WITH THIS FORECAST PACKAGE WAS TO LOWER TEMPERATURES
CENTRAL AS LOW CLOUD COVER IS NOW FORECAST TO PERSIST THROUGH THE
AFTERNOON AS PER THE LAST FEW HIGH RES HRRR MODEL RUNS ALONG WITH
THE LATEST NAM/RAP LOW LEVEL RH FORECAST. STILL EXPECT CLEARING
WEST...THOUGH STRATUS FIELD IS EXTENSIVE. HIGH RES MODELS INDICATE
OVC CIGS TRENDING FEW-SCT 16-19Z ACROSS MY WEST...SO WILL MONITOR
IN CASE CLOUD COVER NEEDS TO BE INCREASED AND TEMPS DROPPED.
UPDATE ISSUED AT 640 AM CDT THU MAY 14 2015
SHOWERS CONTINUE TO LIFT SLOWLY NORTHWARD ACROSS CENTRAL AND
EASTERN NORTH DAKOTA. LATEST BOWMAN RADAR SHOWS RETURNS DRYING UP
OVER WESTERN NORTH DAKOTA...THUS CURRENT RADAR TRENDS LOOK GOOD.
OTHERWISE NO SIGNIFICANT UPDATES TO THE CURRENT FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU MAY 14 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE WIDESPREAD
SHOWERS TODAY WITH SOME AREAS CENTRAL SEEING HEAVY RAINFALL.
CURRENTLY...AN UPPER LEVEL LOW/SHORTWAVE LIFTING NORTHEAST THROUGH
THE CENTRAL AND NORTHERN PLAINS WAS ASSOCIATED WITH WIDESPREAD
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ACROSS THE STATE. LIGHTNING
ACTIVITY HAD DECREASED IN THE LAST HOUR...AND MESOANALYSIS INDICATES
THAT CAPE HAS DECREASED ACROSS THE REGION. AT THE SURFACE...LOW
PRESSURE WAS OVER WYOMING WITH A WARM FRONT EXTENDING FROM THE LOW
NORTHEASTWARD TO NEAR FORT YATES TO NEAR DEVILS LAKE TO THE
NORTHEAST CORNER OF NORTH DAKOTA.
FORECAST CAPE VALUES FOR TODAY ARE LOW ENOUGH TO KEEP THE MENTION OF
THUNDER OUT OF THE FORECAST FOR THE DAYTIME PERIOD. PRECIPITABLE
WATER FORECASTS OF 1.00" TO 1.20" FOR SOUTH CENTRAL NORTH
DAKOTA...ALONG THE SURFACE WARM FRONT. WIDESPREAD AREAS OF 0.50" OF
RAIN ARE POSSIBLE TODAY ALONG AND EAST OF A LINE FROM THE TURTLE
MOUNTAINS TO BISMARCK/MANDAN TO GRANT COUNTY. LOCALLY HIGHER AMOUNTS
ARE POSSIBLE.
THE UPPER LEVEL SHORTWAVE AND SURFACE WARM FRONT ARE PROGGED TO MOVE
EAST TODAY. EXPECT SHOWERS TO DECREASE FROM WEST TO EAST
TODAY...LINGERING IN CENTRAL NORTH DAKOTA THIS AFTERNOON BEFORE
TAPERING OFF DURING THE EVENING HOURS. AS THE SURFACE WARM FRONT
MOVES EAST...HIGH PRESSURE IN SOUTH CENTRAL CANADA WILL PUSH
SOUTHWARD INTO THE STATE. HIGHS TODAY SHOULD RANGE IN THE 50S TO
LOWER 60S...WITH LOWS TONIGHT FROM THE UPPER 30S TO MID 40S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU MAY 14 2015
STRONG VERTICALLY STACKED SYSTEM WILL INFLUENCE THE WEATHER ACROSS
THE NORTHERN PLAINS FRIDAY THROUGH SUNDAY. MAIN FORECAST ISSUES IN
THE LONG TERM ARE SEVERE POTENTIAL ON SATURDAY...PRECIPITATION
AMOUNTS AND POSSIBLE LOCALIZED FLOODING ISSUES THROUGH THE WEEKEND
AND THE POTENTIAL FOR FREEZING TEMPERATURES MONDAY TUESDAY
MORNINGS ON THE BACK SIDE OF THIS SYSTEM.
WE START OFF ON A QUIET NOTE FRIDAY AS THE UPPER LEVEL SYSTEM
TRACKS ACROSS THE INTER-MOUNTAIN WEST AND BEGINS TO TAKE SHAPE
OVER THE NORTHERN HIGH PLAINS. WE BEGIN THE DAY DRY WITH SURFACE
HIGH PRESSURE OVER THE FORECAST AREA. SOUTHEAST FLOW ALOFT WILL
INCREASE OVER WESTERN NORTH DAKOTA AS CYCLOGENESIS TAKES PLACE
OVER THE NORTHERN AND CENTRAL HIGH PLAINS. PRECIPITATION IS
EXPECTED TO DEVELOP BY AFTERNOON OVER THE SOUTHWEST AND BEGIN TO
SPREAD NORTH AND EAST.
FRIDAY NIGHT THROUGH SATURDAY MORNING...STRONG WARM ADVECTION
ENVELOPES WESTERN AND CENTRAL NORTH DAKOTA WITH A SURFACE AND
UPPER LOW DEVELOPING OVER NORTHEAST MONTANA. MODELS ARE PRETTY
SIMILAR IN BRINGING A BAND OF PRECIPITATION SOUTHWEST TO NORTHEAST
ACROSS THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY MORNING...WITH
THE MAJORITY OF THE PRECIPITATION OVER THE NORTHERN TIER COUNTIES
ALONG THE DEFORMATION ZONE BY MIDDAY SATURDAY. INSTABILITY ALOFT
IS LIMITED INITIALLY BUT IS EXPECTED TO INCREASE DURING THE NIGHT
ACROSS NORTHERN SOUTH DAKOTA INTO SOUTHERN NORTH DAKOTA. MOST
UNSTABLE CAPES OF 500-1000 J/KG WITH 20-40KTS OF 0-6KM SHEAR LAY
ACROSS THE NORTHERN SOUTH DAKOTA BORDER LATE FRIDAY NIGHT INTO
EARLY SATURDAY MORNING. THUS A THREAT OF SEVERE WEATHER CAN NOT BE
RULED OUT DURING THIS PERIOD...BUT EXPECT THE BETTER THREAT WILL
REMAIN SOUTH OF THE BORDER.
SATURDAY AFTERNOON...POSSIBLY AS EARLY AS LATE SATURDAY MORNING
THE FIRST WAVE OF PRECIPITATION WILL HAVE MOVED THROUGH AND MODELS
SUGGEST A DRY SLOT WORKING INTO CENTRAL NORTH DAKOTA AS AN 80 KT
UPPER LEVEL JET PUSHES INTO EASTERN NORTH DAKOTA BY AROUND MIDDAY
SATURDAY. THIS SHOULD ALLOW FOR A DESTABILIZING ATMOSPHERE DURING
THE LATE MORNING AND AFTERNOON AS SURFACE TEMPERATURES RISE INTO
THE 70S ACROSS THE SOUTHERN HALF OF THE STATE. A STRONG SOUTHERN
STREAM JET OVER THE SOUTHWEST U.S. BEGINS LIFTING INTO THE
SOUTHERN AND CENTRAL PLAINS...ALLOWING THE NORTHERN STACKED SYSTEM
OVER EASTERN MONTANA TO BEGIN MOVING EAST. ALTHOUGH DIRECTIONAL
SHEAR IS NOT IMPRESSIVE...SUFFICIENT BULK SHEAR AND CAPE WILL BE
AVAILABLE DURING THE LATE MORNING THROUGH THE AFTERNOON THAT
SEVERE STORMS ARE POSSIBLE. WILL STILL NEED TO MONITOR TRENDS OF
THE NEXT DAY OR SO TO HOPEFULLY GET A BETTER IDEA.
SATURDAY NIGHT THROUGH SUNDAY...ANY SEVERE WEATHER THREAT SATURDAY
SHOULD QUICKLY DIMINISH FROM WEST TO EAST SATURDAY NIGHT INTO
SUNDAY MORNING AS THE SURFACE LOW CONTINUES TO TRACK EAST ACROSS
THE DAKOTAS. STRONG NORTHERLY FLOW WILL BRING MUCH COOLER
TEMPERATURES FROM WEST TO EAST SUNDAY...WITH MAINLY IN THE 40S
NORTH AND WEST...TO THE LOWER 60S SOUTHEAST. THE STRONG SOUTHERN
SHORTWAVE LIFTING THROUGH THE SOUTHERN AND CENTRAL PLAINS SATURDAY
MOVES INTO THE NORTHERN PLAINS SUNDAY AND MERGES WITH THE STACKED
SYSTEM TRACKING ACROSS THE DAKOTAS. BY SUNDAY AFTERNOON THE THREAT
OF SEVERE WEATHER WILL BE TO THE EAST OF THE DAKOTAS...BUT A BAND
OF PRECIPITATION IN THE DEFORMATION ZONE IS EXPECTED OVER EASTERN
AND POSSIBLY BACK INTO CENTRAL NORTH DAKOTA. THUS SOME PRETTY
HEFTY PRECIPITATION AMOUNTS COULD FALL OVER SOUTH CENTRAL INTO
NORTHEAST NORTH DAKOTA. WILL NEED TO MONITOR FOR SOME AREAS
RECEIVING ENOUGH RAIN TO PRODUCE LOCAL FLOODING ISSUES. ESPECIALLY
IF THEY GET HIT WITH PRECIPITATION A FEW TIMES BEFORE THIS.
PRECIPITATION FINALLY MOVES OUT OF THE AREA BY SUNDAY EVENING WITH
COLD HIGH PRESSURE BUILDING OVER THE AREA INTO EARLY NEXT WEEK.
WITH THE SURFACE HIGH MOVING INTO NORTH DAKOTA BY MONDAY MORNING
IT LOOKS LIKE A GOOD BET THAT WE WILL NEED A FROST ADVISORY OR
MORE LIKELY A FREEZE WARNING...IF CURRENT TEMPERATURE TRENDS HOLD.
WE COULD STILL BE DEALING WITH FROST ON TUESDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 142 PM CDT THU MAY 14 2015
WIDESPREAD MVFR-IFR CONDITIONS WILL CONTINUE MOST LOCATIONS TODAY.
SHRA WILL ALSO CONTINUE TO SPREAD NORTH AND EAST...ENDING AT KJMS
22-00Z. CONDITIONS SHOULD STILL IMPROVE TO VFR OVER PORTIONS OF
NORTHWEST NORTH DAKOTA LATER THIS THURSDAY AFTERNOON...WHILE MOST
AREAS WILL REMAIN IFR-MVFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...TWH
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1028 AM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 1029 AM CDT THU MAY 14 2015
SURFACE LOW PRESSURE CENTERED OVER WESTERN NEBRASKA WITH A QUASI-
STATIONARY SURFACE FRONT EXTENDING FROM THE LOW NORTH-NORTHEAST
ACROSS THE CENTRAL DAKOTAS INTO NORTHEASTERN NORTH DAKOTA. STRONG
MID LEVEL S/WV TROUGH LIFTING ACROSS THE EASTERN DAKOTAS TOWARDS
THE UPPER MISSISSIPPI VALLEY REGION. SHOWERS...SOME AREAS
MODERATE...CONTINUE ALONG THE FRONTAL ZONE ACROSS SOUTH CENTRAL
NORTH DAKOTA INTO NORTHEASTERN NORTH DAKOTA THIS MORNING. RAINFALL
AMOUNTS WITHIN THE BAND HAVE GENERALLY BEEN IN THE RANGE OF
0.5-0.75"...WITH AMOUNTS IN EARLIER CONVECTIVE BANDS IN EXCESS OF
AN INCH.
SHOWERS WILL CONTINUE TO SLOWLY LIFT NORTH AND EAST AS THE DAY
PROGRESSES...AND SHOULD BE ENTIRELY OUT OF MY EASTERN COUNTIES BY
03Z.
OTHER UPDATE WITH THIS FORECAST PACKAGE WAS TO LOWER TEMPERATURES
CENTRAL AS LOW CLOUD COVER IS NOW FORECAST TO PERSIST THROUGH THE
AFTERNOON AS PER THE LAST FEW HIGH RES HRRR MODEL RUNS ALONG WITH
THE LATEST NAM/RAP LOW LEVEL RH FORECAST. STILL EXPECT CLEARING
WEST...THOUGH STRATUS FIELD IS EXTENSIVE. HIGH RES MODELS INDICATE
OVC CIGS TRENDING FEW-SCT 16-19Z ACROSS MY WEST...SO WILL MONITOR
IN CASE CLOUD COVER NEEDS TO BE INCREASED AND TEMPS DROPPED.
UPDATE ISSUED AT 640 AM CDT THU MAY 14 2015
SHOWERS CONTINUE TO LIFT SLOWLY NORTHWARD ACROSS CENTRAL AND
EASTERN NORTH DAKOTA. LATEST BOWMAN RADAR SHOWS RETURNS DRYING UP
OVER WESTERN NORTH DAKOTA...THUS CURRENT RADAR TRENDS LOOK GOOD.
OTHERWISE NO SIGNIFICANT UPDATES TO THE CURRENT FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU MAY 14 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE WIDESPREAD
SHOWERS TODAY WITH SOME AREAS CENTRAL SEEING HEAVY RAINFALL.
CURRENTLY...AN UPPER LEVEL LOW/SHORTWAVE LIFTING NORTHEAST THROUGH
THE CENTRAL AND NORTHERN PLAINS WAS ASSOCIATED WITH WIDESPREAD
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ACROSS THE STATE. LIGHTNING
ACTIVITY HAD DECREASED IN THE LAST HOUR...AND MESOANALYSIS INDICATES
THAT CAPE HAS DECREASED ACROSS THE REGION. AT THE SURFACE...LOW
PRESSURE WAS OVER WYOMING WITH A WARM FRONT EXTENDING FROM THE LOW
NORTHEASTWARD TO NEAR FORT YATES TO NEAR DEVILS LAKE TO THE
NORTHEAST CORNER OF NORTH DAKOTA.
FORECAST CAPE VALUES FOR TODAY ARE LOW ENOUGH TO KEEP THE MENTION OF
THUNDER OUT OF THE FORECAST FOR THE DAYTIME PERIOD. PRECIPITABLE
WATER FORECASTS OF 1.00" TO 1.20" FOR SOUTH CENTRAL NORTH
DAKOTA...ALONG THE SURFACE WARM FRONT. WIDESPREAD AREAS OF 0.50" OF
RAIN ARE POSSIBLE TODAY ALONG AND EAST OF A LINE FROM THE TURTLE
MOUNTAINS TO BISMARCK/MANDAN TO GRANT COUNTY. LOCALLY HIGHER AMOUNTS
ARE POSSIBLE.
THE UPPER LEVEL SHORTWAVE AND SURFACE WARM FRONT ARE PROGGED TO MOVE
EAST TODAY. EXPECT SHOWERS TO DECREASE FROM WEST TO EAST
TODAY...LINGERING IN CENTRAL NORTH DAKOTA THIS AFTERNOON BEFORE
TAPERING OFF DURING THE EVENING HOURS. AS THE SURFACE WARM FRONT
MOVES EAST...HIGH PRESSURE IN SOUTH CENTRAL CANADA WILL PUSH
SOUTHWARD INTO THE STATE. HIGHS TODAY SHOULD RANGE IN THE 50S TO
LOWER 60S...WITH LOWS TONIGHT FROM THE UPPER 30S TO MID 40S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU MAY 14 2015
STRONG VERTICALLY STACKED SYSTEM WILL INFLUENCE THE WEATHER ACROSS
THE NORTHERN PLAINS FRIDAY THROUGH SUNDAY. MAIN FORECAST ISSUES IN
THE LONG TERM ARE SEVERE POTENTIAL ON SATURDAY...PRECIPITATION
AMOUNTS AND POSSIBLE LOCALIZED FLOODING ISSUES THROUGH THE WEEKEND
AND THE POTENTIAL FOR FREEZING TEMPERATURES MONDAY TUESDAY
MORNINGS ON THE BACK SIDE OF THIS SYSTEM.
WE START OFF ON A QUIET NOTE FRIDAY AS THE UPPER LEVEL SYSTEM
TRACKS ACROSS THE INTER-MOUNTAIN WEST AND BEGINS TO TAKE SHAPE
OVER THE NORTHERN HIGH PLAINS. WE BEGIN THE DAY DRY WITH SURFACE
HIGH PRESSURE OVER THE FORECAST AREA. SOUTHEAST FLOW ALOFT WILL
INCREASE OVER WESTERN NORTH DAKOTA AS CYCLOGENESIS TAKES PLACE
OVER THE NORTHERN AND CENTRAL HIGH PLAINS. PRECIPITATION IS
EXPECTED TO DEVELOP BY AFTERNOON OVER THE SOUTHWEST AND BEGIN TO
SPREAD NORTH AND EAST.
FRIDAY NIGHT THROUGH SATURDAY MORNING...STRONG WARM ADVECTION
ENVELOPES WESTERN AND CENTRAL NORTH DAKOTA WITH A SURFACE AND
UPPER LOW DEVELOPING OVER NORTHEAST MONTANA. MODELS ARE PRETTY
SIMILAR IN BRINGING A BAND OF PRECIPITATION SOUTHWEST TO NORTHEAST
ACROSS THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY MORNING...WITH
THE MAJORITY OF THE PRECIPITATION OVER THE NORTHERN TIER COUNTIES
ALONG THE DEFORMATION ZONE BY MIDDAY SATURDAY. INSTABILITY ALOFT
IS LIMITED INITIALLY BUT IS EXPECTED TO INCREASE DURING THE NIGHT
ACROSS NORTHERN SOUTH DAKOTA INTO SOUTHERN NORTH DAKOTA. MOST
UNSTABLE CAPES OF 500-1000 J/KG WITH 20-40KTS OF 0-6KM SHEAR LAY
ACROSS THE NORTHERN SOUTH DAKOTA BORDER LATE FRIDAY NIGHT INTO
EARLY SATURDAY MORNING. THUS A THREAT OF SEVERE WEATHER CAN NOT BE
RULED OUT DURING THIS PERIOD...BUT EXPECT THE BETTER THREAT WILL
REMAIN SOUTH OF THE BORDER.
SATURDAY AFTERNOON...POSSIBLY AS EARLY AS LATE SATURDAY MORNING
THE FIRST WAVE OF PRECIPITATION WILL HAVE MOVED THROUGH AND MODELS
SUGGEST A DRY SLOT WORKING INTO CENTRAL NORTH DAKOTA AS AN 80 KT
UPPER LEVEL JET PUSHES INTO EASTERN NORTH DAKOTA BY AROUND MIDDAY
SATURDAY. THIS SHOULD ALLOW FOR A DESTABILIZING ATMOSPHERE DURING
THE LATE MORNING AND AFTERNOON AS SURFACE TEMPERATURES RISE INTO
THE 70S ACROSS THE SOUTHERN HALF OF THE STATE. A STRONG SOUTHERN
STREAM JET OVER THE SOUTHWEST U.S. BEGINS LIFTING INTO THE
SOUTHERN AND CENTRAL PLAINS...ALLOWING THE NORTHERN STACKED SYSTEM
OVER EASTERN MONTANA TO BEGIN MOVING EAST. ALTHOUGH DIRECTIONAL
SHEAR IS NOT IMPRESSIVE...SUFFICIENT BULK SHEAR AND CAPE WILL BE
AVAILABLE DURING THE LATE MORNING THROUGH THE AFTERNOON THAT
SEVERE STORMS ARE POSSIBLE. WILL STILL NEED TO MONITOR TRENDS OF
THE NEXT DAY OR SO TO HOPEFULLY GET A BETTER IDEA.
SATURDAY NIGHT THROUGH SUNDAY...ANY SEVERE WEATHER THREAT SATURDAY
SHOULD QUICKLY DIMINISH FROM WEST TO EAST SATURDAY NIGHT INTO
SUNDAY MORNING AS THE SURFACE LOW CONTINUES TO TRACK EAST ACROSS
THE DAKOTAS. STRONG NORTHERLY FLOW WILL BRING MUCH COOLER
TEMPERATURES FROM WEST TO EAST SUNDAY...WITH MAINLY IN THE 40S
NORTH AND WEST...TO THE LOWER 60S SOUTHEAST. THE STRONG SOUTHERN
SHORTWAVE LIFTING THROUGH THE SOUTHERN AND CENTRAL PLAINS SATURDAY
MOVES INTO THE NORTHERN PLAINS SUNDAY AND MERGES WITH THE STACKED
SYSTEM TRACKING ACROSS THE DAKOTAS. BY SUNDAY AFTERNOON THE THREAT
OF SEVERE WEATHER WILL BE TO THE EAST OF THE DAKOTAS...BUT A BAND
OF PRECIPITATION IN THE DEFORMATION ZONE IS EXPECTED OVER EASTERN
AND POSSIBLY BACK INTO CENTRAL NORTH DAKOTA. THUS SOME PRETTY
HEFTY PRECIPITATION AMOUNTS COULD FALL OVER SOUTH CENTRAL INTO
NORTHEAST NORTH DAKOTA. WILL NEED TO MONITOR FOR SOME AREAS
RECEIVING ENOUGH RAIN TO PRODUCE LOCAL FLOODING ISSUES. ESPECIALLY
IF THEY GET HIT WITH PRECIPITATION A FEW TIMES BEFORE THIS.
PRECIPITATION FINALLY MOVES OUT OF THE AREA BY SUNDAY EVENING WITH
COLD HIGH PRESSURE BUILDING OVER THE AREA INTO EARLY NEXT WEEK.
WITH THE SURFACE HIGH MOVING INTO NORTH DAKOTA BY MONDAY MORNING
IT LOOKS LIKE A GOOD BET THAT WE WILL NEED A FROST ADVISORY OR
MORE LIKELY A FREEZE WARNING...IF CURRENT TEMPERATURE TRENDS HOLD.
WE COULD STILL BE DEALING WITH FROST ON TUESDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 640 AM CDT THU MAY 14 2015
WIDESPREAD MVFR WITH LCL IFR CONDITIONS WILL CONTINUE TO SPREAD
OVER THE AREA WITH SHRA SPREADING NORTHWARD.
CONDITIONS WILL IMPROVE TO VFR OVER PORTIONS OF NORTHWEST NORTH
DAKOTA THURSDAY AFTERNOON...WHILE MOST AREAS WILL REMAIN IFR-MVFR.
KISN SHOULD SEE A RETURN OF MVFR-IFR AFT 02Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...TWH
AVIATION...JV
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
950 PM CDT FRI MAY 15 2015
.UPDATE...
THUNDERSTORMS IN EASTERN NM/WEST TX/WEST TX PANHANDLE STILL
EXPECTED TO MOVE INTO PARTS OF THE FA LATE TONIGHT INTO EARLY
SATURDAY. LEFT POPS ALONE FOR NOW BUT SOME OF THE MODELS WOULD
SUGGEST THAT MUCH OF THIS ACTIVITY WILL CLIP NW OK AND LIFT INTO
KANSAS WITH MAYBE SOME SCATTERED ACTIVITY FURTHER SOUTH IN OUR
AREA. THERE IS STILL ENOUGH INSTABILITY THAT SOME STRONG TO SEVERE
STORMS ARE STILL POSSIBLE IN WESTERN AND NORTHERN PARTS OF THE FA.
THE REST OF THE FORECAST GENERALLY LOOKED GOOD AS WELL JUST MADE
SOME ADJUSTMENTS TO A FEW PARAMETERS TO SHOW CURRENT TRENDS.
UPDATES OUT SOON.
&&
.PREV DISCUSSION... /ISSUED 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.
&&
$$
25/30
AREA FORECAST DISCUSSION
NWS TULSA OK
641 PM CDT FRI MAY 15 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR CONDITIONS WILL GIVE WAY TO MVFR CONDITIONS LATE TONIGHT INTO
SATURDAY MORNING. ADDED TEMPO FOR THUNDERSTORMS AT KFSM LATE
TONIGHT INTO EARLY SATURDAY MORNING AS HRRR CONTINUES TO HINT
AT SCATTERED THUNDERSTORMS DEVELOPING ACROSS SOUTHEAST OKLAHOMA AND
WEST-CENTRAL ARKANSAS LATE TONIGHT. WENT WITH PROB30 FOR THUNDERSTORMS
SATURDAY AFTERNOON AFTER 18Z FOR EASTERN OKLAHOMA TAF SITES. COULD SEE
ISOLATED TO SCATTERED THUNDERSTORMS DEVELOP IN ADVANCE OF MAIN LINE OF
THUNDERSTORMS EXPECTED AFTER VALID TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 318 PM CDT FRI MAY 15 2015/
DISCUSSION...
ON THE LARGER SCALE...PERSISTENT SPLIT FLOW BLOCK CONTINUES OUT
WEST...WITH RIDGING CENTERED OVER FLORIDA. THE CENTRAL/SOUTHERN
PLAINS IS IN THE STORM TRACK LAID OUT BETWEEN THE TWO PRIMARY
UPPER FEATURES...AND WILL REMAIN THAT WAY FOR THE NEXT 7 TO 10
DAYS. SEVERAL MORE ROUNDS OF RAIN/STORMS ARE EXPECTED...AND MORE
FLOODING IS LIKELY IN SOME SPOTS...ALONG WITH SEVERE WEATHER
POTENTIAL OVER THE WEEKEND.
A LEAD SUBTROPICAL WAVE BROUGHT SCATTERED SHOWERS AND STORMS THIS
MORNING BUT THIS ACTIVITY HAS SINCE MOVED EAST. SOME WIDELY
SCATTERED AFTERNOON DEVELOPMENT IS POSSIBLE IN THE EAST THRU ABOUT
03Z. THERE WILL BE A BREAK FOR AWHILE DURING THE OVERNIGHT WITH
SOME UPTICK IN ACTIVITY POSSIBLE SATURDAY MORNING AS WARM
ADVECTION INCREASES AHEAD OF APPROACHING WESTERN CONUS UPPER
TROUGH. THE MAIN SHOW WILL GET GOING OVER WESTERN OK AND WESTERN
NORTH TX SATURDAY AFTERNOON AS HEIGHT FALLS OVERSPREAD THE
DRYLINE/PACIFIC FRONT. THESE STORMS...LIKELY SUPERCELLS...WILL
EVENTUALLY CONGEAL INTO ONE OR MORE CLUSTERS/LINES AS THEY MOVE
INTO OUR AREA SATURDAY EVENING. MODEL QPF FIELDS CONTINUE TO
INDICATE LOCALIZED HEAVY RAIN POTENTIAL WITH THESE STORMS IN A
MOIST DEEP LAYER ENVIRONMENT WITH POSSIBLE TRAINING. THUS...HAVE
HOISTED A FLASH FLOOD WATCH TO COVER AREAS THAT WERE HIT HARD BY
LAST WEEK`S HEAVY RAINS AND FLOODING FOR SATURDAY NIGHT. DATA
INDICATES THAT THIS MIGHT NEED TO BE EXTENDED THRU SUNDAY AS
PACIFIC FRONT STALLS AND ANOTHER ROUND OF CONVECTION DEVELOPS
SUNDAY EVENING OVER SE OK. THE POLAR FRONT WILL PUSH THROUGH THE
REGION MONDAY...BRINGING ONE MORE POTENTIAL ROUND OF SCATTERED
STORMS BEFORE ENDING MONDAY EVENING.
AFTER A RELATIVELY QUIET TUESDAY...RAIN/STORM CHANCES RAMP BACK UP
TUESDAY NIGHT INTO WEDNESDAY AS THE NEXT TROUGH EJECTS INTO THE
PLAINS FROM THE WESTERN SPLIT FLOW BLOCK. THE FORECAST STAYS
RATHER MESSY THROUGH THE END OF THE WEEK...WITH THE MEAN
BAROCLINIC ZONE DRAPED OVER THE REGION...FOCUSING MORE STORM
DEVELOPMENT.
LACY
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM 7 PM SATURDAY TO 7 AM SUNDAY FOR OKZ049-
OKZ053-OKZ060-OKZ064-OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-
OKZ073-OKZ074-OKZ075-OKZ076.
AR...FLASH FLOOD WATCH FROM 7 PM SATURDAY TO 7 AM SUNDAY FOR ARZ019-
ARZ020-ARZ029.
&&
$$
AVIATION...10
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1136 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL DRIFT NORTH INTO THE AREA OVERNIGHT. THE FRONT
WILL STALL OVER THE REGION THIS WEEKEND...ACCOMPANIED BY VARIABLE
CLOUDS AND SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A
RELATIVELY STRONG COLD FRONT WILL PUSH ACROSS THE AREA MONDAY
NIGHT AND TUESDAY...USHERING IN ANOTHER COOL...DRY AIRMASS FOR
LATE TUESDAY THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LATEST RADAR CONTINUES TO SHOW WIDELY SCATTERED DISORGANIZED
SHOWERS MOVING EAST...FAVORING THE NORTHERN HALF OR SO OF THE
FORECAST AREA. LATEST HRRR KEEPS THESE CELLS TRACKING ACROSS
OVERNIGHT. IT ALSO SHOWS A CONTINUED EROSION OF STABILITY SO
BEFORE THE NIGHT IS OUT A THUNDERSTORM CANNOT BE RULED OUT.
MIN TEMPS OVERNIGHT WILL VARY FROM THE MID TO UPPER 50S ACROSS
THE NRN AND WRN MTNS...TO THE LOWER 60S THROUGHOUT THE LOWER SUSQ
VALLEY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SFC WARM/STATIONARY SHOULD EXTEND FROM NWRN PENN TO THE LOWER OR
MID SUSQ VALLEY SAT/SATURDAY EVENING BEFORE BECOMING ORIENTED A
BIT MORE NORTH/SOUTH NEAR OR JUST TO THE WEST OF THE SUSQ VALLEY
SAT NIGHT. ALTHOUGH THE BEST CHC FOR SHOWERS AND TSRA WILL BE NEAR
THE SLOWLY MEANDERING QUASI-BACKDOOR FRONTAL BOUNDARY...A SHOWER
OR TSTM CAN/T BE RULED OUT AT PRACTICALLY ANY TIME DURING THIS
PERIOD. WILL KEEP POPS IN THE 30-50 PERCENT RANGE BETWEEN 12Z SAT
AND 12Z SUNDAY.
HIGH TEMPS SAT WILL BE IN THE MID 70S ACROSS THE HIGHER TERRAIN OF
THE NORTH AND WEST...AND AROUND 80F IN THE LOWER SUSQ VALLEY. LOWS
EARLY SUNDAY WILL RANGE FROM THE U50S NORTH...TO MID 60S IN THE
SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LEAD SHORTWAVE ENERGY CLIMBING THE WESTERN-SIDE OF ANOMALOUS
500MB RIDGE OVER THE EASTERN US...ALONG WITH ABOVE NORMAL PWATS
AND DIURNAL INSTABILITY WILL HELP PROMOTE SCATTERED CONVECTION ON
SUNDAY...ESPECIALLY ALONG/SOUTH OF THE QUASI-STNRY/WARM FRONTAL
BOUNDARY PIVOTING OVER THE AREA. USED A BLEND FOR POPS/QPF WHICH
FAVORED THE LAUREL HIGHLANDS AND SOUTH-CENTRAL MTNS ON DAY 3.
GIVEN LACK OF FORCING AND LOSS OF DAYTIME HEATING...CUT BACK POPS
TO THE MID-CHC RANGE SUNDAY NIGHT /40 PERCENT WEST TO 30 PERCENT
EAST/.
THE VIGOROUS/DEEP CLOSED LOW EJECTING OUT OF THE SOUTHWESTERN
U.S. SHOULD REACH THE NORTHERN PLAINS BY 00Z MON...WHERE THE
MODELS SHOW IT SLOWING DOWN AND EVENTUALLY BECOMING ABSORBED INTO
AN UPPER TROUGH CROSSING HUDSON BAY. THIS HAS APPEARED TO SLOW
THE EASTWARD PROGRESSION OF ITS TRAILING COLD FRONT BY 12HRS OR
SO...NOW PROGGED TO CROSS THE AREA DURING THE DAYTIME ON TUESDAY
(PREVIOUSLY MONDAY NIGHT/AM TUESDAY). THIS SLOWER TREND WAS EVIDENT
IN THE GUIDANCE AND HAVE ADJUSTED TEMPS AND POPS ACCORDINGLY. THE
PARENT SHORTWAVE WILL LOSE MUCH OF ITS AMPLITUDE AS IT TRACKS
THROUGH THE UPPER GREAT LAKES AND FOR NOW DOES NOT APPEAR TO POSE
A SIGNIFICANT SVR WX RISK FOR EARLY NEXT WEEK.
IN THE WAKE OF THE COLD FRONTAL PASSAGE...A RESPECTABLE ANTICYCLONE
WILL EXTEND SEWD FROM THE UPPER MIDWEST WITH COOLER AND NOTICEABLY
DRIER AIR FILTERING INTO THE REGION FOR THE MID TO LATE WEEK
PERIOD. THIS PATTERN SHOULD SUPPRESS THE PCPN RISK TO THE SOUTH OF
CENTRAL PA WITH GENERALLY FAIR WEATHER AND SEASONABLY COOL TO
MODERATING TEMPERATURES PREVAILING AT DAYS 6-8. ALSO OF NOTE IS
THE RISK FOR PATCHY FROST ON MAY 21ST/THURSDAY MORNING MAINLY OVER
THE NORTH-CENTRAL ZONES WHERE ECENS/GFS ENSEMBLE MOS GUIDANCE IS
SHOWING MID 30S AT BFD...JUST IN TIME FOR THE START OF THE GROWING
SEASON.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
INCREASING HIGH-BASED CU AND THICK ALTOCU ALTOSTRATUS WILL BE
ADVANCING EAST ACROSS THE STATE LATE THIS AFTERNOON AND EVENING
JUST ALONG AND AHEAD OF AN UPPER SHORTWAVE MOVING EAST FROM THE
LOWER GLAKES...AND ON THE NORTH SIDE OF A WARM FRONT ACROSS ERN
OHIO AND NRN WVA.
ISOLATED...MAINLY LIGHT SHOWERS WILL REDEVELOP NOW THROUGH THE
POST MIDNIGHT HOURS AS AREA OF LIFT ASSOCIATED WITH SHORTWAVE
ENERGY PUSHES EAST INTO THE WARM AND MOIST AIRMASS IN PLACE ACROSS
PA. SHOWERS...AND POSSIBLE A RUMBLE OR TWO OF THUNDER...SHOULD BE
MAINLY CONFINED TO THE NW MTNS...BUT MAY PROGRESS SOUTH AND EAST
OVERNIGHT. SHOWERS MAY REDUCE VSBYS OR CIGS INTO THE MVFR CATEGORY
FOR A TIME WITH ANY SHOWERS.
ALSO...EXPECT SOME VALLEY FOG TO DEVELOP OVERNIGHT IN AREAS WHERE
SHOWERS OCCUR...LEADING TO POCKETS OF MVFR VSBYS OVERNIGHT.
MAINTAINED A SEVERAL HOUR PERIOD OF LLWS /IN THE 1.5-2KFT AGL
LAYER/ LATER TONIGHT AS A SWRLY LLJ LIFT NE FROM THE OHIO VALLEY.
OUTLOOK...
SAT-TUE MORNING...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS WITH LOCAL REDUCTIONS TO MVFR AND BRIEF IFR POSSIBLE.
WED-THU...MAINLY VFR WITHIN A COOLER/DRIER AIRMASS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1018 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL DRIFT NORTH INTO THE AREA OVERNIGHT. THE FRONT
WILL STALL OVER THE REGION THIS WEEKEND...ACCOMPANIED BY VARIABLE
CLOUDS AND SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A
RELATIVELY STRONG COLD FRONT WILL PUSH ACROSS THE AREA MONDAY
NIGHT AND TUESDAY...USHERING IN ANOTHER COOL...DRY AIRMASS FOR
LATE TUESDAY THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LATEST RADAR CONTINUES TO SHOW WIDELY SCATTERED DISORGANIZED
SHOWERS MOVING EAST...FAVORING THE NORTHERN HALF OR SO OF THE
FORECAST AREA. LATEST HRRR KEEPS THESE CELLS TRACKING ACROSS
OVERNIGHT. IT ALSO SHOWS A CONTINUED EROSION OF STABILITY SO
BEFORE THE NIGHT IS OUT A THUNDERSTORM CANNOT BE RULED OUT.
MIN TEMPS OVERNIGHT WILL VARY FROM THE MID TO UPPER 50S ACROSS
THE NRN AND WRN MTNS...TO THE LOWER 60S THROUGHOUT THE LOWER SUSQ
VALLEY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SFC WARM/STATIONARY SHOULD EXTEND FROM NWRN PENN TO THE LOWER OR
MID SUSQ VALLEY SAT/SATURDAY EVENING BEFORE BECOMING ORIENTED A
BIT MORE NORTH/SOUTH NEAR OR JUST TO THE WEST OF THE SUSQ VALLEY
SAT NIGHT. ALTHOUGH THE BEST CHC FOR SHOWERS AND TSRA WILL BE NEAR
THE SLOWLY MEANDERING QUASI-BACKDOOR FRONTAL BOUNDARY...A SHOWER
OR TSTM CAN/T BE RULED OUT AT PRACTICALLY ANY TIME DURING THIS
PERIOD. WILL KEEP POPS IN THE 30-50 PERCENT RANGE BETWEEN 12Z SAT
AND 12Z SUNDAY.
HIGH TEMPS SAT WILL BE IN THE MID 70S ACROSS THE HIGHER TERRAIN OF
THE NORTH AND WEST...AND AROUND 80F IN THE LOWER SUSQ VALLEY. LOWS
EARLY SUNDAY WILL RANGE FROM THE U50S NORTH...TO MID 60S IN THE
SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LEAD SHORTWAVE ENERGY CLIMBING THE WESTERN-SIDE OF ANOMALOUS
500MB RIDGE OVER THE EASTERN US...ALONG WITH ABOVE NORMAL PWATS
AND DIURNAL INSTABILITY WILL HELP PROMOTE SCATTERED CONVECTION ON
SUNDAY...ESPECIALLY ALONG/SOUTH OF THE QUASI-STNRY/WARM FRONTAL
BOUNDARY PIVOTING OVER THE AREA. USED A BLEND FOR POPS/QPF WHICH
FAVORED THE LAUREL HIGHLANDS AND SOUTH-CENTRAL MTNS ON DAY 3.
GIVEN LACK OF FORCING AND LOSS OF DAYTIME HEATING...CUT BACK POPS
TO THE MID-CHC RANGE SUNDAY NIGHT /40 PERCENT WEST TO 30 PERCENT
EAST/.
THE VIGOROUS/DEEP CLOSED LOW EJECTING OUT OF THE SOUTHWESTERN
U.S. SHOULD REACH THE NORTHERN PLAINS BY 00Z MON...WHERE THE
MODELS SHOW IT SLOWING DOWN AND EVENTUALLY BECOMING ABSORBED INTO
AN UPPER TROUGH CROSSING HUDSON BAY. THIS HAS APPEARED TO SLOW
THE EASTWARD PROGRESSION OF ITS TRAILING COLD FRONT BY 12HRS OR
SO...NOW PROGGED TO CROSS THE AREA DURING THE DAYTIME ON TUESDAY
(PREVIOUSLY MONDAY NIGHT/AM TUESDAY). THIS SLOWER TREND WAS EVIDENT
IN THE GUIDANCE AND HAVE ADJUSTED TEMPS AND POPS ACCORDINGLY. THE
PARENT SHORTWAVE WILL LOSE MUCH OF ITS AMPLITUDE AS IT TRACKS
THROUGH THE UPPER GREAT LAKES AND FOR NOW DOES NOT APPEAR TO POSE
A SIGNIFICANT SVR WX RISK FOR EARLY NEXT WEEK.
IN THE WAKE OF THE COLD FRONTAL PASSAGE...A RESPECTABLE ANTICYCLONE
WILL EXTEND SEWD FROM THE UPPER MIDWEST WITH COOLER AND NOTICEABLY
DRIER AIR FILTERING INTO THE REGION FOR THE MID TO LATE WEEK
PERIOD. THIS PATTERN SHOULD SUPPRESS THE PCPN RISK TO THE SOUTH OF
CENTRAL PA WITH GENERALLY FAIR WEATHER AND SEASONABLY COOL TO
MODERATING TEMPERATURES PREVAILING AT DAYS 6-8. ALSO OF NOTE IS
THE RISK FOR PATCHY FROST ON MAY 21ST/THURSDAY MORNING MAINLY OVER
THE NORTH-CENTRAL ZONES WHERE ECENS/GFS ENSEMBLE MOS GUIDANCE IS
SHOWING MID 30S AT BFD...JUST IN TIME FOR THE START OF THE GROWING
SEASON.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
INCREASING HIGH-BASED CU AND THICK ALTOCU ALTOSTRATUS WILL BE
ADVANCING EAST ACROSS THE STATE LATE THIS AFTERNOON AND EVENING
JUST ALONG AND AHEAD OF AN UPPER SHORTWAVE MOVING EAST FROM THE
LOWER GLAKES...AND ON THE NORTH SIDE OF A WARM FRONT ACROSS ERN
OHIO AND NRN WVA.
ISOLATED...LIGHT SHOWERS WILL MOVE EAST ACROSS MAINLY CENTRAL AND
EASTERN SECTIONS THROUGH LATE THIS EVENING. LITTLE AFFECT ON VSBYS
OR CIGS IS EXPECTED. SOME VALLEY FOG MAY DEVELOP AFTER SUNSET IN
AREAS WHERE SHOWERS DID FALL TODAY...LEADING TO POCKETS OF MVFR
VSBYS OVERNIGHT.
MAINTAINED A SEVERAL HOUR PERIOD OF LLWS /IN THE 1.5-2KFT AGL
LAYER/ LATER TONIGHT AS A SWRLY LLJ LIFT NE FROM THE OHIO VALLEY.
A PERIOD OF LOWER MVFR /AND EVEN SOME IFR/ IS POSSIBLE LATE
TONIGHT ACROSS NWRN PENN /MAINLY NEAR KBFD/ AS LATEST MODEL
GUIDANCE INDICATES THE POTENTIAL FOR A CLUSTER OF TSRA TO FORM AND
TRACK EAST NEAR THE PA/NY BORDER BETWEEN 04Z-10Z SAT.
OUTLOOK...
SAT-TUE MORNING...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS WITH LOCAL REDUCTIONS TO MVFR AND BRIEF IFR POSSIBLE.
WED-THU...MAINLY VFR WITHIN A COOLER/DRIER AIRMASS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
743 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL DRIFT NORTH INTO THE AREA OVERNIGHT. THE FRONT
WILL STALL OVER THE REGION THIS WEEKEND...ACCOMPANIED BY VARIABLE
CLOUDS AND SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A
RELATIVELY STRONG COLD FRONT WILL PUSH ACROSS THE AREA MONDAY
NIGHT AND TUESDAY...USHERING IN ANOTHER COOL...DRY AIRMASS FOR
LATE TUESDAY THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LATEST RADAR SHOWS WIDELY SCATTERED LIGHT SHOWERS MOVING EAST
ACROSS THE REGION. LOOKING AT HRRR GUIDANCE FOR THE NEXT SEVERAL
HOURS SUGGESTS SHOWERS TO BE MORE WIDESPREAD THAN WHAT SEEMS TO BE
HAPPENING. WITH LITTLE IN THE WAY OF UPSTREAM ACTIVITY...HAVE
BASICALLY LOWERED THE EXPECTATIONS FOR THE REMAINDER OF THE
EVENING AND OVERNIGHT.
THE WARM FRONT WILL SLOW OR STALL AS IT ENTERS N-CENT PA LATER
TONIGHT. THE FLAT UPPER RIDGE WILL CONTINUE TO ALLOW WEAK RIPPLES
OF SHORTWAVE ENERGY TO RIDE EAST INTO THE REGION...KEEPING THE
CHANCE OF SHOWERS IN THE FORECAST...ALTHOUGH MUCH OF THE TIME WILL
BE RAIN FREE IN MOST AREAS.
MIN TEMPS OVERNIGHT WILL VARY FROM THE MID TO UPPER 50S ACROSS
THE NRN AND WRN MTNS...TO THE LOWER 60S THROUGHOUT THE LOWER SUSQ
VALLEY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SFC WARM/STATIONARY SHOULD EXTEND FROM NWRN PENN TO THE LOWER OR
MID SUSQ VALLEY SAT/SATURDAY EVENING BEFORE BECOMING ORIENTED A
BIT MORE NORTH/SOUTH NEAR OR JUST TO THE WEST OF THE SUSQ VALLEY
SAT NIGHT. ALTHOUGH THE BEST CHC FOR SHOWERS AND TSRA WILL BE NEAR
THE SLOWLY MEANDERING QUASI-BACKDOOR FRONTAL BOUNDARY...A SHOWER
OR TSTM CAN/T BE RULED OUT AT PRACTICALLY ANY TIME DURING THIS
PERIOD. WILL KEEP POPS IN THE 30-50 PERCENT RANGE BETWEEN 12Z SAT
AND 12Z SUNDAY.
HIGH TEMPS SAT WILL BE IN THE MID 70S ACROSS THE HIGHER TERRAIN OF
THE NORTH AND WEST...AND AROUND 80F IN THE LOWER SUSQ VALLEY. LOWS
EARLY SUNDAY WILL RANGE FROM THE U50S NORTH...TO MID 60S IN THE
SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LEAD SHORTWAVE ENERGY CLIMBING THE WESTERN-SIDE OF ANOMALOUS
500MB RIDGE OVER THE EASTERN US...ALONG WITH ABOVE NORMAL PWATS
AND DIURNAL INSTABILITY WILL HELP PROMOTE SCATTERED CONVECTION ON
SUNDAY...ESPECIALLY ALONG/SOUTH OF THE QUASI-STNRY/WARM FRONTAL
BOUNDARY PIVOTING OVER THE AREA. USED A BLEND FOR POPS/QPF WHICH
FAVORED THE LAUREL HIGHLANDS AND SOUTH-CENTRAL MTNS ON DAY 3.
GIVEN LACK OF FORCING AND LOSS OF DAYTIME HEATING...CUT BACK POPS
TO THE MID-CHC RANGE SUNDAY NIGHT /40 PERCENT WEST TO 30 PERCENT
EAST/.
THE VIGOROUS/DEEP CLOSED LOW EJECTING OUT OF THE SOUTHWESTERN
U.S. SHOULD REACH THE NORTHERN PLAINS BY 00Z MON...WHERE THE
MODELS SHOW IT SLOWING DOWN AND EVENTUALLY BECOMING ABSORBED INTO
AN UPPER TROUGH CROSSING HUDSON BAY. THIS HAS APPEARED TO SLOW
THE EASTWARD PROGRESSION OF ITS TRAILING COLD FRONT BY 12HRS OR
SO...NOW PROGGED TO CROSS THE AREA DURING THE DAYTIME ON TUESDAY
(PREVIOUSLY MONDAY NIGHT/AM TUESDAY). THIS SLOWER TREND WAS EVIDENT
IN THE GUIDANCE AND HAVE ADJUSTED TEMPS AND POPS ACCORDINGLY. THE
PARENT SHORTWAVE WILL LOSE MUCH OF ITS AMPLITUDE AS IT TRACKS
THROUGH THE UPPER GREAT LAKES AND FOR NOW DOES NOT APPEAR TO POSE
A SIGNIFICANT SVR WX RISK FOR EARLY NEXT WEEK.
IN THE WAKE OF THE COLD FRONTAL PASSAGE...A RESPECTABLE ANTICYCLONE
WILL EXTEND SEWD FROM THE UPPER MIDWEST WITH COOLER AND NOTICEABLY
DRIER AIR FILTERING INTO THE REGION FOR THE MID TO LATE WEEK
PERIOD. THIS PATTERN SHOULD SUPPRESS THE PCPN RISK TO THE SOUTH OF
CENTRAL PA WITH GENERALLY FAIR WEATHER AND SEASONABLY COOL TO
MODERATING TEMPERATURES PREVAILING AT DAYS 6-8. ALSO OF NOTE IS
THE RISK FOR PATCHY FROST ON MAY 21ST/THURSDAY MORNING MAINLY OVER
THE NORTH-CENTRAL ZONES WHERE ECENS/GFS ENSEMBLE MOS GUIDANCE IS
SHOWING MID 30S AT BFD...JUST IN TIME FOR THE START OF THE GROWING
SEASON.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
INCREASING HIGH-BASED CU AND THICK ALTOCU ALTOSTRATUS WILL BE
ADVANCING EAST ACROSS THE STATE LATE THIS AFTERNOON AND EVENING
JUST ALONG AND AHEAD OF AN UPPER SHORTWAVE MOVING EAST FROM THE
LOWER GLAKES...AND ON THE NORTH SIDE OF A WARM FRONT ACROSS ERN
OHIO AND NRN WVA.
ISOLATED...LIGHT SHOWERS WILL MOVE EAST ACROSS MAINLY CENTRAL AND
EASTERN SECTIONS THROUGH LATE THIS EVENING. LITTLE AFFECT ON VSBYS
OR CIGS IS EXPECTED. SOME VALLEY FOG MAY DEVELOP AFTER SUNSET IN
AREAS WHERE SHOWERS DID FALL TODAY...LEADING TO POCKETS OF MVFR
VSBYS OVERNIGHT.
MAINTAINED A SEVERAL HOUR PERIOD OF LLWS /IN THE 1.5-2KFT AGL
LAYER/ LATER TONIGHT AS A SWRLY LLJ LIFT NE FROM THE OHIO VALLEY.
A PERIOD OF LOWER MVFR /AND EVEN SOME IFR/ IS POSSIBLE LATE
TONIGHT ACROSS NWRN PENN /MAINLY NEAR KBFD/ AS LATEST MODEL
GUIDANCE INDICATES THE POTENTIAL FOR A CLUSTER OF TSRA TO FORM AND
TRACK EAST NEAR THE PA/NY BORDER BETWEEN 04Z-10Z SAT.
OUTLOOK...
SAT-TUE MORNING...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS WITH LOCAL REDUCTIONS TO MVFR AND BRIEF IFR POSSIBLE.
WED-THU...MAINLY VFR WITHIN A COOLER/DRIER AIRMASS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
703 PM EDT FRI MAY 15 2015
.SYNOPSIS...
A WARM FRONT WILL DRIFT NORTH INTO THE AREA OVERNIGHT. THE FRONT
WILL STALL OVER THE REGION THIS WEEKEND...ACCOMPANIED BY VARIABLE
CLOUDS AND SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A
RELATIVELY STRONG COLD FRONT WILL PUSH ACROSS THE AREA MONDAY
NIGHT AND TUESDAY...USHERING IN ANOTHER COOL...DRY AIRMASS FOR
LATE TUESDAY THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LATEST RADAR SHOWS WIDELY SCATTERED LIGHT SHOWERS MOVING EAST
ACROSS THE REGION. LOOKING AT HRRR GUIDANCE FOR THE NEXT SEVERAL
HOURS SUGGESTS SHOWERS TO BE MORE WIDESPREAD THAN WHAT SEEMS TO BE
HAPPENING. WITH LITTLE IN THE WAY OF UPSTREAM ACTIVITY...HAVE
BASICALLY LOWERED THE EXPECTATIONS FOR THE REMAINDER OF THE
EVENING AND OVERNIGHT.
THE WARM FRONT WILL SLOW OR STALL AS IT ENTERS N-CENT PA LATER
TONIGHT. THE FLAT UPPER RIDGE WILL CONTINUE TO ALLOW WEAK RIPPLES
OF SHORTWAVE ENERGY TO RIDE EAST INTO THE REGION...KEEPING THE
CHANCE OF SHOWERS IN THE FORECAST...ALTHOUGH MUCH OF THE TIME WILL
BE RAIN FREE IN MOST AREAS.
MIN TEMPS OVERNIGHT WILL VARY FROM THE MID TO UPPER 50S ACROSS
THE NRN AND WRN MTNS...TO THE LOWER 60S THROUGHOUT THE LOWER SUSQ
VALLEY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SFC WARM/STATIONARY SHOULD EXTEND FROM NWRN PENN TO THE LOWER OR
MID SUSQ VALLEY SAT/SATURDAY EVENING BEFORE BECOMING ORIENTED A
BIT MORE NORTH/SOUTH NEAR OR JUST TO THE WEST OF THE SUSQ VALLEY
SAT NIGHT. ALTHOUGH THE BEST CHC FOR SHOWERS AND TSRA WILL BE NEAR
THE SLOWLY MEANDERING QUASI-BACKDOOR FRONTAL BOUNDARY...A SHOWER
OR TSTM CAN/T BE RULED OUT AT PRACTICALLY ANY TIME DURING THIS
PERIOD. WILL KEEP POPS IN THE 30-50 PERCENT RANGE BETWEEN 12Z SAT
AND 12Z SUNDAY.
HIGH TEMPS SAT WILL BE IN THE MID 70S ACROSS THE HIGHER TERRAIN OF
THE NORTH AND WEST...AND AROUND 80F IN THE LOWER SUSQ VALLEY. LOWS
EARLY SUNDAY WILL RANGE FROM THE U50S NORTH...TO MID 60S IN THE
SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LEAD SHORTWAVE ENERGY CLIMBING THE WESTERN-SIDE OF ANOMALOUS
500MB RIDGE OVER THE EASTERN US...ALONG WITH ABOVE NORMAL PWATS
AND DIURNAL INSTABILITY WILL HELP PROMOTE SCATTERED CONVECTION ON
SUNDAY...ESPECIALLY ALONG/SOUTH OF THE QUASI-STNRY/WARM FRONTAL
BOUNDARY PIVOTING OVER THE AREA. USED A BLEND FOR POPS/QPF WHICH
FAVORED THE LAUREL HIGHLANDS AND SOUTH-CENTRAL MTNS ON DAY 3.
GIVEN LACK OF FORCING AND LOSS OF DAYTIME HEATING...CUT BACK POPS
TO THE MID-CHC RANGE SUNDAY NIGHT /40 PERCENT WEST TO 30 PERCENT
EAST/.
THE VIGOROUS/DEEP CLOSED LOW EJECTING OUT OF THE SOUTHWESTERN
U.S. SHOULD REACH THE NORTHERN PLAINS BY 00Z MON...WHERE THE
MODELS SHOW IT SLOWING DOWN AND EVENTUALLY BECOMING ABSORBED INTO
AN UPPER TROUGH CROSSING HUDSON BAY. THIS HAS APPEARED TO SLOW
THE EASTWARD PROGRESSION OF ITS TRAILING COLD FRONT BY 12HRS OR
SO...NOW PROGGED TO CROSS THE AREA DURING THE DAYTIME ON TUESDAY
(PREVIOUSLY MONDAY NIGHT/AM TUESDAY). THIS SLOWER TREND WAS EVIDENT
IN THE GUIDANCE AND HAVE ADJUSTED TEMPS AND POPS ACCORDINGLY. THE
PARENT SHORTWAVE WILL LOSE MUCH OF ITS AMPLITUDE AS IT TRACKS
THROUGH THE UPPER GREAT LAKES AND FOR NOW DOES NOT APPEAR TO POSE
A SIGNIFICANT SVR WX RISK FOR EARLY NEXT WEEK.
IN THE WAKE OF THE COLD FRONTAL PASSAGE...A RESPECTABLE ANTICYCLONE
WILL EXTEND SEWD FROM THE UPPER MIDWEST WITH COOLER AND NOTICEABLY
DRIER AIR FILTERING INTO THE REGION FOR THE MID TO LATE WEEK
PERIOD. THIS PATTERN SHOULD SUPPRESS THE PCPN RISK TO THE SOUTH OF
CENTRAL PA WITH GENERALLY FAIR WEATHER AND SEASONABLY COOL TO
MODERATING TEMPERATURES PREVAILING AT DAYS 6-8. ALSO OF NOTE IS
THE RISK FOR PATCHY FROST ON MAY 21ST/THURSDAY MORNING MAINLY OVER
THE NORTH-CENTRAL ZONES WHERE ECENS/GFS ENSEMBLE MOS GUIDANCE IS
SHOWING MID 30S AT BFD...JUST IN TIME FOR THE START OF THE GROWING
SEASON.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
INCREASING HIGH-BASED CU AND THICK ALTOCU ALTOSTRATUS WILL BE
ADVANCING EAST ACROSS THE STATE LATE THIS AFTERNOON AND EVENING
JUST ALONG AND AHEAD OF AN UPPER SHORTWAVE MOVING EAST FROM THE
LOWER GLAKES...AND ON THE NORTH SIDE OF A WARM FRONT ACROSS ERN
OHIO AND NRN WVA.
SHOWERS WITH PERIODS OF MVFR CIGS AND VSBYS WILL MOVE ACROSS THE
NRN HALF OF PENN...WHILE THE APPROX SE HALF OF THE STATE WILL STAY
VFR FOR MUCH OF THE TIME THROUGH TONIGHT. INCLUDED A SEVERAL HOUR
PERIOD OF LLWS /IN THE 1.5-2KFT AGL LAYER/ LATER TONIGHT AS A
SWRLY LLJ LIFT NE FROM THE OHIO VALLEY.
A PERIOD OF LOWER MVFR /AND EVEN SOME IFR/ IS POSSIBLE LATE
TONIGHT ACROSS NWRN PENN /MAINLY NEAR KBFD/ AS LATEST MODEL
GUIDANCE INDICATES THE POTENTIAL FOR A CLUSTER OF TSRA TO FORM AND
TRACK EAST NEAR THE PA/NY BORDER BETWEEN 04Z-10Z SAT.
OUTLOOK...
SAT-TUE MORNING...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS WITH LOCAL REDUCTIONS TO MVFR AND BRIEF IFR POSSIBLE.
WED-THU...MAINLY VFR WITHIN A COOLER/DRIER AIRMASS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
919 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 914 PM CDT FRI MAY 15 2015
UPDATED EARLIER THIS EVENING TO REDUCE THE CHANCES FOR RAIN AND
STORMS THROUGH THE OVERNIGHT HOURS TO SLIGHT CHANCE OR NONE.
HOWEVER AM RELUNCTANT TO RADICALLY ALTER SHOWER AND THUNDERSTORM
CHANCES LATE TONIGHT AS THE HRRR AND NOW THE NEW NAM12 SHOW SOME
DEVELOPMENT ARCING THROUGH IN A NORTHWEST TO SOUTHEAST BAND. THIS
OCCURS LATE TONIGHT AND EARLY SATURDAY ALONG AN ELEVATED WARM
FRONT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 414 PM CDT FRI MAY 15 2015
DEEP UPPER TROUGHING OVER THE SOUTHWESTERN UNITED STATES CONTINUES
TO POUR MOISTURE NORTHWARD INTO THE PLAINS THIS AFTERNOON.
HOWEVER...FOCUS FOR CONVECTION HAS BEEN SPLIT THROUGH MUCH OF THE
DAY...WITH MCV LIFTING NORTHWARD THROUGH WESTERN SD AND A SECONDARY
SHORTWAVE DRIVING CONVECTION IN THE MID/LOWER MISSOURI RIVER VALLEY.
OVERHEAD...WEAK ISENTROPIC ASSENT TIED NEAR THE 305K SFC CONTINUES
TO PRODUCE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
HEADING INTO THE LATE AFTERNOON AND EVENING HOURS...MAIN FOCUS TURNS
TO WESTERN NE/SD AS UPPER JET BEGINS TO NOSE INTO THE PLAINS.
ALREADY A WELL DEVELOPED WARM FRONT STRETCHING ACROSS PORTIONS OF
NEBRASKA...BUT THE REINFORCING ELEVATED CONVECTION HAS KEPT THIS
BOUNDARY SW OF THE CWA THROUGH THE DAY. WITH 850:700 MB FLOW
BEGINNING TO BACK INTO THE WESTERN PLAINS ONGOING SHOWER ACTIVITY IN
THE LOCAL AREA MAY BEGIN TO WANE AS EVENING APPROACHES WITH
CONVECTION OVER NEBRASKA PANHANDLE TAKING OFF. WITH THE SFC WARM
FRONT TRYING TO REACH THE NE/SD LINE IN SOUTH CENTRAL SD...AN
ISOLATED STORM MAY STILL BE POSSIBLE EARLY THIS EVENING NEAR THE
MISSOURI RIVER.
THROUGH THE OVERNIGHT HOURS...LATEST HIGH RES GUIDANCE HINTS AT
SEVERAL CLUSTERS OF STORMS LIFTING NORTHEAST ACROSS NE/SD OVERNIGHT.
AS THE LEAD SHORTWAVE ENTERS THE PLAINS LATE THIS EVENING...WE MAY
BEGIN TO SEE THE LLJ VEER SOUTHWESTERLY WHICH COULD REIGNITE
ADDITIONAL ELEVATED CONVECTION FURTHER SOUTHEAST THROUGH CENTRAL
NEBRASKA AND SOUTH CENTRAL SD ALONG ELEVATED BOUNDARY LIFTING
NORTHEAST. INSTABILITY WOULD BE WANING AT THIS POINT...BUT COULD
BE DEALING WITH MARGINAL HAIL OR PERHAPS BRIEF WIND GUSTS GIVEN
PARALLEL ORIENTATION OF LOW LVL FLOW. THIS STRONGER STORM RISK WOULD
MAINLY BE WEST OF THE JAMES RIVER INTO THE EARLY MORNING
HOURS...HOWEVER THE RISK OF CONVECTION COULD SPREAD ALL THE WAY
EASTWARD INTO WESTERN MN.
FOR SATURDAY...A VERY TRICKY FORECAST REMAINS. DEEP MERIDIONAL FLOW
IS EXPECTED TO FURTHER ENHANCE MOISTURE OVERNIGHT INTO THE
AREA...WITH LLJ KEEPING ELEVATED CONVECTION LINGERING OVER THE CWA
INTO EARLY SATURDAY MORNING. A MUCH STRONGER WAVE WILL PIVOT INTO
THE PLAINS SATURDAY AFTERNOON. THE BIGGEST QUESTION FOR
SATURDAY...GIVEN THE DEEP MERIDIONAL FLOW...IS THE DEGREE OF CLOUD
COVER AND INSTABILITY THAT CAN GROW THROUGH THE AFTERNOON. THERE
ARE SOME HINTS THAT LINGERING CLOUD COVER AND ELEVATED SHOWERS MAY
WORK TO REINFORCE THE EML IN THE AFTERNOON...WITH MODELS HINTING AT
A WEAK SHORTWAVE RACING NORTHWARD AND THROUGH THE AREA BY MID-DAY
SATURDAY. HOWEVER...THE BEST CHANCE FOR ANY MORE SUBSTANTIAL GROWTH
IN SFC BASED INSTABILITY WILL BE ALONG A NORTH-SOUTH ORIENTATED
SFC BOUNDARY ACROSS WEST CENTRAL SD/NE. THAT SAID...CANNOT RULE
OUT A FEW STRONG STORM CLUSTERS...MAINLY BOWING SEGMENTS FURTHER
EAST...ESPECIALLY IF STRONGER POCKETS OF INSTABILITY CAN GROW
GIVEN THE UNIDIRECTIONAL FLOW AND DECENT SPEED SHEAR ALOFT.
AGAIN...VERY CONDITIONAL AND UNCERTAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 414 PM CDT FRI MAY 15 2015
THE CHANCE FOR THUNDERSTORMS WILL INCREASE RAPIDLY SATURDAY
EVENING AS A STRONG SHORT WAVE TROUGH AND JET STREAK MOVE
NORTHWARD INTO SOUTH DAKOTA. EXPECTED SCENARIO AT THIS TIME IS
THAT THUNDERSTORM COVERAGE WILL SLOWLY INCREASE THROUGH THE
EVENING AS WAVE APPROACHES WITH A CLUSTER OF SHOWERS AND
THUNDERSTORMS MOVING INTO THE MISSOURI VALLEY AROUND SUNSET AND
REACHING I90 BEFORE MIDNIGHT. WITH ALMOST NO CAPPING
INVERSION...THESE SHOWERS AND STORMS WILL CONTINUE DEVELOP AND MOVE
NORTHEAST THROUGH THE NIGHT. WITH WIDESPREAD STORMS...SEVERE
WEATHER IS UNLIKELY EXCEPT AHEAD OF THE MAIN CLUSTER OF STORMS IN
THE EVENING...ASSUMING ENOUGH INSTABILITY IS PRESENT TO PRODUCE A
STRONG ENOUGH UPDRAFT TO SUPPORT MARGINALLY SEVERE HAIL. AS NOTED
ABOVE...THIS THREAT IS VERY CONDITIONAL AND UNCERTAIN AS CAPES BY
EVENING WILL LIKELY BE AT OR BELOW 1000 J/KG. INSTEAD EXPECTING A
WIDESPREAD 0.5 TO 1.0 INCH OF RAIN SATURDAY NIGHT. LOCAL AMOUNTS
COULD EXCEED 1.5 INCHES IN PORTIONS OF THE AREA. WITH THE CLOUDS
AND PRECIPITATION LOWS WILL BE AROUND 60.
ON SUNDAY...SHOWERS AND STORMS WILL LINGER INTO THE
MORNING...ESPECIALLY NORTH OF I90. THEN A DRY SLOT WILL MOVE OVER
THE AREA WHICH SHOULD BRING A RESPITE TO THE PRECIPITATION TO MOST
AREA. A DRY LINE IS THEN EXPECTED TO MOVE ACROSS THE AREA ON
SUNDAY MORNING. AT THIS POINT...HAVE LOW POPS WITH THE DRY LINE
AS UPPER FORCING FOR ASCENT IS MINIMAL AND ATMOSPHERE WILL BE
FAIRLY STABLE FOLLOWING THE OVERNIGHT CONVECTION. A COLD FRONT
WILL MOVE ACROSS SUNDAY AFTERNOON. WITH LIMITED MOISTURE...
PRECIPITATION WILL NOT BE AS WIDESPREAD AND IS EXPECTED TO BE
FOCUSED CLOSER TO THE UPPER LOW MOVING ACROSS CENTRAL SD AND
EASTERN ND. SO HAVE THE HIGHEST POPS NORTH OF INTERSTATE 90. WHILE
THUNDER IS POSSIBLE WITH ANY STORMS...WITH THE LIMITED INSTABILITY
AND MOISTURE...HAVE PRIMARILY RAIN SHOWERS WITH A LOWER
PROBABILITY OF THUNDER. HIGHS WILL BE IN THE MID 70S WHERE THE
COLD FRONT WILL MOVE THROUGH IN THE LATE AFTERNOON...WITH MID 60S
IN CENTRAL SOUTH DAKOTA WHERE THERE WILL BE MORE CLOUDS AND MUCH
EARLY COLD FRONTAL PASSAGE.
FROM SUNDAY AFTERNOON INTO MONDAY EVENING...THE FOCUS WILL SHIFT
FOR RAIN TO WIND AND COLD. ONCE THE COLD FRONT MOVES THROUGH
SUNDAY AFTERNOON...NORTHWEST WIND WILL REALLY INCREASE WITH GUSTS
WELL ABOVE 30 MPH BY SUNDAY EVENING. WINDS WILL DROP LITTLE ON
SUNDAY NIGHT AND THEN PICK BACK UP WITH SUSTAINED WINDS OVER 20
MPH ON MONDAY. TEMPERATURES WILL FALL FAIRLY QUICKLY SUNDAY NIGHT
WITH LOWS IN THE 30S TO LOW 40S. ON MONDAY...THERE WILL BE A LOT
OF LOW LEVEL MOISTURE AROUND SO EVEN IF THERE IS SOME BREAKS IN
CLOUDS MONDAY MORNING...WITH 850 MB TEMPS BELOW ZERO...SUNSHINE
WILL BE SELF DESTRUCTIVE AND SKIES IN MOST AREA WILL BECOME CLOUDY
BY LATE MORNING. MOST PLACES WILL LIKELY REACH HIGHS IN THE 40S TO
MID 50S BY EARLY AFTERNOON AND THEN HOLDING STEADY. AT THIS POINT
THE GFS BUFR SOUNDINGS SHOW A VERY SHALLOW UNSTABLE LAYER SO NOT
EXPECTING SHOWERS TO DEVELOP BUT WILL NEED TO MONITOR THE
POTENTIAL AS NAM/ECMWF SOUNDINGS WOULD SUPPORT A MIX OF GRAUPAL
AND RAIN IN PORTIONS OF SW MN AND EAST CENTRAL SD.
IN THE LONGER RANGE...MONDAY NIGHT THROUGH FRIDAY...BELOW NORMAL
TEMPERATURES ARE EXPECTED TO CONTINUE. THE MODELS HAVE A GENERAL
AGREEMENT WITH A LONG WAVE TROUGH OVER THE AREA THROUGH THE WEEK.
THE BEST CHANCE OF RAIN WILL BE ON LATE TUESDAY NIGHT AND
WEDNESDAY BUT THERE IS SOME QUESTION HOW FAR EAST THE RAIN WILL
GET AS EASTERLY FLOW FROM HIGH PRESSURE WILL ACT TO LIMIT MOISTURE
FLOW INTO THE AREA AND MAY PREVENT RAIN FROM REACHING SW MN AND
PORTIONS OF NW IA. TEMPERATURES THROUGH WEDNESDAY WILL BE IN THE
50S WITH UNSEASONABLY COLD AIR BOTH DAYS AND CLOUDS AND RAIN ON
WEDNESDAY. A GRADUAL WARM UP WILL BEGIN ON THURSDAY AND CONTINUE
INTO FRIDAY ALTHOUGH IT IS MOST LIKELY HIGHS WILL REMAIN IN THE
60S. A STRONGER WAVE WILL ALSO APPROACH LATER FRIDAY WHICH MAY
BRING A CHANCE OF THUNDERSTORMS BY AFTERNOON. HOWEVER...THE BETTER
CHANCE WILL BE INTO MEMORIAL DAY WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 631 PM CDT FRI MAY 15 2015
CURRENTLY...DRIER AIR IS MOVING INTO THE FORECAST AREA FROM
NEBRASKA...GIVING OUR FORECAST AREA UPPER END MVFR TO VFR
CONDITIONS. THIS WILL LIKELY BE THE TREND IN THE TAF SITES FOR
THIS EVENING...FAVORING VFR. HOWEVER BETWEEN 06Z AND 12Z
SATURDAY...A VARIETY OF MODELS INCLUDING THE NAM...RAP13...GEM
REGIONAL AND GFS ARE ALL SHOWING A REDEVELOPMENT OF LOW STRATUS
LIKELY IN THE IFR CATEGORY. THEREFORE KEPT THIS TREND GOING FROM
THE PREVIOUS TAF SET...LINGERING IFR IN THE AREA UNTIL LATE
MORNING SATURDAY WHEN CONDITIONS MIX UPWARD TO UPPER END MVFR OR
VFR BY AFTERNOON. FOR NOW...KEPT THE THUNDER CHANCES OUT OF THE
TAF SITES AS TSRA LOOKS TOO SKITTISH TO PUT IN. AFTER THIS TAF
PERIOD HOWEVER...THUNDERSTORMS WILL BE VERY LIKELY SATURDAY NIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...DUX
LONG TERM...SCHUMACHER
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
628 PM CDT FRI MAY 15 2015
.DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION...
&&
.AVIATION...
SHORT WAVE TROUGH AXIS LOOKS TO BE PUSHING THROUGH THE AREA THIS
EVENING. SHRA/TSRA LOOK TO BE ENDING THIS EVENING. MAINLY JUST
SOME -SHRA TO IMPACT TERMINALS SOUTH OF HOUSTON FOR NEXT HR OR
TWO. KEEP SAME TIMING OF MVFR CIGS FOR THE MORNING HOURS THEN
LIFTING TO VFR FOR THE AFTERNOON. ONLY QUESTION MARK WILL AGAIN BE
CONVECTION. MODEL SOUNDINGS SUPPORT SOME TSRA ACTIVITY WITH DAY
TIME HEATING. MENTION VCSH IN TAFS FOR NOW AS WRF/NAM/GFS
SOLUTIONS DO NOT HINT AT MUCH ACTIVITY TOMORROW. WINDS WILL BE
QUITE GUSTY AS PRESSURE GRADIENT TIGHTENS IN RESPONSE TO LOW
PRESSURE IN THE PLAINS.
39
&&
.PREV DISCUSSION... /ISSUED 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 7 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...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS AMARILLO TX
417 PM CDT THU MAY 14 2015
.DISCUSSION...
WATER VAPOR CHANNEL AND VISIBLE BOTH SHOW EXTENSIVE HIGH LEVEL
MOISTURE/CIRRUS STREAMING NORTHEASTWARD ACROSS NEW MEXICO INTO THE
SOUTHERN AND CENTRAL PLAINS AHEAD OF A DEEP WEST COAST MID-UPPER
LOW. CURRENT OBSERVATIONS SHOW SOUTHERLY SURFACE WINDS AND NEAR
NORMAL TEMPERATURES FOR MID MAY ACROSS OUR REGION. THE SHALLOW MOIST
LAYER EVIDENT IN 12Z KAMA AND KMAF SOUNDINGS HAS MIXED OUT SOME THIS
AFTERNOON WITH A SLIGHT DOWNWARD TREND IN SURFACE DEW POINTS NOTED
IN REGIONAL OBSERVATIONS. SLIGHT BACKING TO SURFACE WINDS AND UPSTREAM
DEEPER MOISTURE HAS KEPT SURFACE DEW POINTS FROM MIXING OUT FURTHER
AND SHORT TERM MODEL FORECAST SOUNDINGS SHOWS GRADUAL DEEPENING OF
LOW LEVEL MOISTURE THROUGH THE EVENING. MODEST MLCAPE IS PRESENT
ACROSS THE AREA BUT EFFECTIVE BULK SHEAR IS MARGINAL AT BEST FOR
STORM ORGANIZATION AND SEVERE WEATHER POTENTIAL. A FEW MARGINALLY
SEVERE THUNDERSTORMS ARE STILL POSSIBLE THIS EVENING. VIS SAT/RADAR
AND LIGHTNING OBS SHOW ISOLATED/SCATTERED CONVECTIVE DEVELOPMENT SO
FAR LIMITED TO SOUTHEAST AND CENTRAL NEW MEXICO AND SOUTHEAST
COLORADO. CU FIELD HAS EXPANDED FURTHER EAST BENEATH CIRRUS SHIELD
ACROSS EASTERN NEW MEXICO AND AS WEAK SHORTWAVE TROUGH APPROACHES
CONVECTION SHOULD EXPAND. CURRENT THINKING IN HOW THIS EVOLVE ALIGNS
WELL WITH WRF AND HRRR MODEL PROGNOSTICATIONS AND RESEMBLE OUTPUT
FROM THESE REASONABLY WELL.
A PATTERN SIMILAR TO WHAT HAS BEEN SEEN RECENTLY AND ONE THAT IS
GENERALLY RECOGNIZED FOR BRINGING OUR REGION HIGHER PROBABILITY
PRECIPITATION CHANCES CONTINUES THROUGH THE FORECAST PERIOD. AFTER
THE DEPARTING WAVE EARLY TOMORROW THE FOCUS SHIFTS TO A PERIOD OF
ASCENT WITH ANOTHER APPROACHING SHORTWAVE AND THIS WILL RESULT IN
ANOTHER FAIRLY HIGH CONFIDENCE ROUND OF PRECIPITATION FRIDAY EVENING
AND OVERNIGHT. MADE MINOR ADJUSTMENTS TO TIMING AND INCREASED BOTH
QPF AND PRECIPITATION PROBABILITIES. MODELS ARE NOT TOO DISSIMILAR
WITH TIMING OF WHAT COULD BE A FAIRLY EXPANSIVE AREA OF
RAIN/THUNDERSTORMS EXITING THE AREA SATURDAY MORNING AND HAVE KEPT
PRECIPITATION CHANCES ACROSS THE EASTERN PORTION OF THE AREA THEN. BY
AFTERNOON MODEL DIFFERENCES IN POSITION OF THE DRYLINE LEAD TO SOME
UNCERTAINTY WITH WHERE CONVECTION WILL REDEVELOP. THE CONSENSUS IS
THIS WILL OCCUR NEAR THE TEXAS/OKLAHOMA STATE LINE...OR SLIGHTLY
WEST. THUS...RETAINED SLIGHT/LOW CHANCE POPS ACROSS THE EASTERNMOST
COUNTIES SATURDAY AFTERNOON. BEHIND THE DRYLINE...DEEP MIXING INTO
FAIRLY STRONG MOMENTUM ALOFT COULD RESULT IN A PERIOD OF NEAR
ADVISORY CRITERIA WINDS ACROSS PORTIONS OF THE AREA.
QUITE WEATHER IS EXPECTED SUNDAY IN BETWEEN TWO WAVES IN A REGION OF
MEAN HEIGHT RISES DUE TO LOW AMPLITUDE RIDGING. YET ANOTHER SYSTEM
TAKES A SIMILAR TRACK AS THE LAST FEW DOWN THE WEST COAST AND INTO
THE DESERT SOUTHWEST BY LATE MONDAY. INCREASING LARGE SCALE ASCENT
AND DEEPENING MOISTURE (PWATS RISING TO WELL ABOVE CLIMATOLOGY)
SHOULD JUSTIFY FAIRLY HIGH PRECIPITATION PROBABILITIES FROM MONDAY
NIGHT THROUGH TUESDAY. THEREAFTER MEDIUM RANGE MODELS DIVERGE BUT THE
GENERAL SOUTHWESTERLY FLOW PATTERN WITHOUT ANY ANTECEDENT SIGNIFICANT
SOUTHEASTWARD PUSH OF LOW LEVEL MOISTURE NECESSITATES AT LEAST LOW
PRECIPITATION PROBABILITIES THROUGH MID WEEK.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 56 81 57 80 48 / 50 10 60 20 5
BEAVER OK 62 84 59 82 50 / 40 20 60 50 20
BOISE CITY OK 53 79 50 73 47 / 30 10 40 10 5
BORGER TX 60 83 59 79 53 / 50 10 60 20 5
BOYS RANCH TX 55 81 58 78 48 / 50 10 60 10 5
CANYON TX 56 80 57 79 49 / 50 10 60 10 5
CLARENDON TX 59 82 59 80 51 / 50 20 60 30 5
DALHART TX 52 80 54 75 46 / 40 10 50 10 5
GUYMON OK 57 82 56 79 49 / 40 10 50 20 10
HEREFORD TX 54 80 57 77 49 / 40 10 60 10 5
LIPSCOMB TX 62 83 61 81 53 / 50 20 60 50 20
PAMPA TX 59 80 57 78 49 / 50 10 60 30 5
SHAMROCK TX 63 82 63 81 53 / 50 20 60 50 20
WELLINGTON TX 64 84 63 83 54 / 50 20 60 60 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
08/17
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 PM CDT THU MAY 14 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 326 PM CDT THU MAY 14 2015
PRIMARY FORECAST CHALLENGES INCLUDE EXITING SHOWERS THIS EVENING...
THEN THUNDERSTORM CHANCES AND SEVERE POTENTIAL FRIDAY NIGHT AND
AGAIN SUNDAY AFTERNOON AND EVENING. 14.12Z MODEL SUITE IN GOOD
OVERALL AGREEMENT AND WILL USE A BLENDED APPROACH.
SO FAR TODAY...RAIN HAS BEEN VERY SLOW TO MOVE EAST PAST THE MS
RIVER DUE TO DRY SUB-600 HPA LAYER. HOWEVER...AS SHORT-WAVE ALOFT
CURRENTLY ACROSS THE EASTERN DAKOTAS INTO SOUTHWEST MN/WESTERN IA
LIFTS TO THE NORTHEAST...RAIN SHOWERS WILL MOVE ACROSS THE REST OF
THE UPPER MS RIVER VALLEY LATE THIS AFTERNOON AND EVENING. SHOWERS
WILL TAPER OFF FROM WEST TO EAST AFTER MIDNIGHT...BUT OVERCAST
SKIES OVERNIGHT WILL KEEP TEMPERATURES ELEVATED IN THE 50S.
FRIDAY WILL BE WARMER AND DRY AS SHORT-WAVE RIDGING MOVES ACROSS
THE REGION. 925 HPA TEMPERATURES RISE TO BETWEEN +14 AND +18
CELSIUS BY 00Z SATURDAY...BUT A MIX OF SUN AND CLOUDS SHOULD
RESULT IN AFTERNOON HIGHS RISING INTO THE UPPER 60S ACROSS NORTH
CENTRAL WI TO THE MID 70S ACROSS PORTIONS OF NORTHEAST IA AND
SOUTHWEST WI. WINDS WILL BE LIGHT AND VARIABLE THROUGH THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 326 PM CDT THU MAY 14 2015
FRIDAY EVENING AND OVERNIGHT...SURFACE LOW PRESSURE WILL LIFT
FROM THE CENTRAL PLAINS INTO THE DAKOTAS AS A LARGE PACIFIC
TROUGH ACROSS THE WESTERN CONUS BEGINS TO PUSH EAST. AN EAST-WEST
ORIENTED WARM FRONT WILL MOVE NORTH INTO THE UPPER MS RIVER VALLEY
WITH 0 TO 3 KM MUCAPE INCREASING TO BETWEEN 500 AND 1500 J/KG
MAINLY SOUTH OF THE I-90 CORRIDOR. AT THE SAME TIME...SHEAR WILL
BE WEAK AROUND 20 KTS OR LESS. SOME ELEVATED STRONG TO LOCALLY
SEVERE THUNDERSTORMS ARE POSSIBLE...BUT COVERAGE WILL BE LIMITED.
PRIMARY THREATS ARE LARGE HAIL AND STRONG WIND.
SATURDAY WILL BE WARM AND HUMID WITH INCREASING LOW-LEVEL MOISTURE/
WARM AIR ADVECTION. 925 HPA TEMPERATURES NEARING +20 CELSIUS WILL
BRING AFTERNOON HIGHS IN THE UPPER 70S TO LOWER 80S. SURFACE DEW
POINT TEMPERATURES WILL ALSO RISE IN THE 60S. AS A RESULT...
INSTABILITY WILL RISE ABOVE 2000 J/KG IN PLACES SATURDAY AFTERNOON...
BUT FORCING/SHEAR IS VERY WEAK WITH CONTINUED RIDGING ALOFT. SOME
SCATTERED SHOWERS AND THUNDERSTORMS COULD DEVELOP...BUT NOT ENOUGH
TO WARRANT ANY MORE THAN A 20 TO 30 PERCENT CHANCE. 0 TO 6 KM
MUCAPE TO REMAIN AT OR BELOW 500 J/KG SATURDAY NIGHT WITH CONCURRENT
DEEP LAYER SHEAR LESS THAN 30 KTS. AGAIN...SOME SCATTERED SHOWERS/
THUNDERSTORMS POSSIBLE OVERNIGHT...BUT MORE SIGNIFICANT CONVECTION
WILL BE FARTHER WEST ACROSS THE PLAINS WHICH COULD PROPAGATE IN
SOME WAY INTO THE UPPER MS RIVER VALLEY BY SUNDAY MORNING.
BEST CHANCE FOR SEVERE CONVECTION ACROSS THE FORECAST AREA WILL BE
SUNDAY AFTERNOON AND EVENING AS A STRONG COLD FRONT SWEEPS ACROSS
THE UPPER MS RIVER VALLEY. 0 TO 6 KM SHEAR INCREASES TO BETWEEN
40 AND 50 KTS...20 TO 30 KTS OF WHICH ARE IN THE 0 TO 1 KM LAYER.
MUCAPE IN THE 0 TO 3 KM LAYER INCREASES TO BETWEEN 1500 AND 2000
J/KG BY 18Z SUNDAY AND WHEN COMBINED WITH STRONG MID-LEVEL
MOISTURE TRANSPORT...EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP...
SOME OF WHICH MAY BE SEVERE. EARLY SUNDAY MORNING CONVECTION FROM
THE PLAINS COMBINED WITH THE SPEED OF THE OVERALL SYSTEM AND
POTENTIAL DRY SLOTTING DO INTRODUCE SOME UNCERTAINTY...BUT LARGE
HAIL AND STRONG WINDS ARE POSSIBLE WITH ANY STRONGER STORMS THAT
DEVELOP. CANNOT RULE OUT AN ISOLATED TORNADO AS WELL GIVEN
STRENGTH OF THE SHEAR. WILL BE ABLE TO FINE-TUNE THE DETAILS OVER
THE COMING DAYS...BUT FOR NOW...PERSONS WITH OUTDOOR PLANS ON
SUNDAY SHOULD PAY CLOSE ATTENTION TO THE LATEST FORECASTS/
STATEMENTS.
COLD FRONT TO SWEEP ACROSS THE AREA SUNDAY NIGHT...RESULTING IN A
MUCH COOLER AND DRY AIR MASS FOR MUCH OF NEXT WEEK. DAILY HIGHS
MONDAY THROUGH THURSDAY UNLIKELY TO BREAK ABOVE THE LOWER 60S WITH
OVERNIGHT LOWS FROM THE MID 30S INTO THE 40S. BROAD SURFACE HIGH
PRESSURE WILL KEEP CONDITIONS MOSTLY DRY...ALTHOUGH THERE IS A
SLIGHT CHANCE FOR SHOWERS WEDNESDAY/THURSDAY AS FLOW ALOFT BECOMES
A BIT MORE ZONAL WITH WEAK SHORT-WAVES MOVING THROUGH THE CENTRAL
CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1206 PM CDT THU MAY 14 2015
THE LIGHT RAIN HAS BEEN VERY SLOW TO ADVANCE EAST TODAY DUE TO THE
DRY AIR IN PLACE OVER WISCONSIN. THE 14.15Z HRRR INDICATES THIS
TREND WILL CONTINUE THROUGH THE AFTERNOON WITH THE LIGHT
RAIN/SPRINKLES NOT REACHING KLSE UNTIL THE MIDDLE OF THE
AFTERNOON. THERE IS ALSO A TREND IN THE HI-RES MESO MODELS THAT
THE ACTIVITY COMING UP OUT OF MISSOURI WILL BECOME THE MORE
DOMINANT AREA OF RAIN CAUSING A DRY SLOT TO DEVELOP NORTH OF IT
AND OVER THE AREA. SOME SUGGESTIONS IN THE REGIONAL RADAR DISPLAY
THAT THIS IS INDEED OCCURRING AND THAT IT WILL TAKE THE MORE
WIDESPREAD ACTIVITY OVER WESTERN IOWA TO SPREAD IN BEFORE THERE
WILL LIKELY BE ANY VISIBILITY RESTRICTIONS OCCURRING. HAVE THUS
PUSHED BACK THE TIMING OF MVFR VISIBILITY AT KLSE UNTIL EARLY THIS
EVENING BUT STILL SHOW IT BY LATE AFTERNOON AT KRST DUE MORE SO TO
SOME LIGHT FOG DEVELOPING AS THE LOW LEVELS CONTINUE TO SATURATE.
CEILINGS WILL ALSO CONTINUE TO COME DOWN WITH THIS SATURATION WITH
KRST EXPECTED TO GO TO IFR THIS AFTERNOON AND KLSE COMING DOWN TO
MVFR THIS EVENING. THE RAIN SHOULD END BY MID TO LATE EVENING WITH
BOTH SITES STAYING IFR/MVFR UNTIL FRIDAY MORNING AS THE WINDS
START TO PICK UP OUT OF THE NORTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1206 PM CDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 307 AM CDT THU MAY 14 2015
WATER VAPOR IMAGERY THIS MORNING SHOWS A VIGOROUS MID-LEVEL TROUGH
LIFTING NORTHEAST ACROSS THE PLAINS WHILE A RIDGE OF HIGH PRESSURE
EXTENDED N/S ACROSS OUR AREA. FORCING FROM THIS TROUGH WAS PRODUCING
A WIDESPREAD SWATH OF SHOWERS ACROSS EASTERN NEB/WESTERN IA...
PUSHING NORTHEAST TOWARD THE AREA. OTHERWISE...PLENTY OF HIGH/MID
CLOUD ACROSS THE FORECAST AREA WITH TEMPERATURES AT 2 AM RANGING
FROM THE LOWER/MID 40S ACROSS NORTHERN AND CENTRAL WI...TO THE
MIDDLE 50S ALONG AND WEST OF THE MISSISSIPPI RIVER.
LOOK FOR THAT MID-LEVEL TROUGH TO CONTINUE LIFTING NORTHEAST INTO
CENTRAL MN/IA BY LATE THIS AFTERNOON. GOOD AMOUNT OF 850-300MB PV-
ADVECTION AND 850MB MOISTURE TRANSPORT WILL CONTINUE TO FUEL SHOWERS
AS THEY SLOWLY PUSH INTO THE AREA FROM WEST TO EAST. DRIER LOWER
LEVELS ASSOCIATED WITH DEPARTING SURFACE HIGH PRESSURE WILL LIKELY
HOLD BULK OF THE SHOWERS WEST OF THE MISSISSIPPI RIVER THROUGH
NOON...BEFORE THEY OVERSPREAD THE REST OF THE AREA THROUGH THE
AFTERNOON HOURS. DUE TO THE CLOUDS AND INCOMING SHOWERS...
TEMPERATURES WILL SUFFER SOMEWHAT...RANGING FROM THE UPPER 50S TO
THE LOWER 60S.
SHOWERS WILL CONTINUE THROUGH MIDNIGHT ACROSS MOST OF THE
AREA...THEN START A SLOW DIMINISHING TREND FROM WEST TO EAST AFTER
MIDNIGHT AS THE TROUGH DEPARTS EAST AND RIDGING BUILDS IN FROM
MN/IA. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE UPPER 40S TO THE
MIDDLE 50S.
APPEARS RAINFALL FROM THIS SYSTEM WILL BE SOMEWHERE IN THE 1/2 TO
3/4 INCH RANGE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 307 AM CDT THU MAY 14 2015
A FEW VERY LIGHT SHOWERS MAY BE ONGOING EARLY FRIDAY MORNING EAST OF
THE MISSISSIPPI RIVER EARLY IN THE MORNING AS THE TROUGH DEPART...
BUT SKIES ARE EXPECTED TO BECOME PARTLY CLOUDY BY AFTERNOON AS A
RIDGE OF HIGH PRESSURE WORKS INTO THE AREA. PLAN ON HIGHS IN THE
UPPER 60S THE THE LOWER 70S.
FOCUS THEN SHIFTS TO THE POTENTIAL FOR SOME STRONG TO SEVERE STORMS
THROUGH THE WEEKEND.
MODELS HAVE BEEN CONSISTENT IN PUSHING A WARM FRONT NORTHWARD
INTO/ACROSS THE AREA FRIDAY NIGHT THROUGH SATURDAY. INCREASING 850MB
MOISTURE TRANSPORT INTO/OVER THE WARM FRONT IS EXPECTED TO FUEL
SCATTERED THUNDERSTORM ACTIVITY. NAM SHOWING MUCAPE OF 1500-2000J/KG
LATE FRIDAY NIGHT INTO SATURDAY MORNING WITH 0-3KM SHEAR OF 20-25KT.
SO...LOOKS LIKE WE HAVE THE POTENTIAL TO GET A FEW STRONGER/MAINLY
PULSE TYPE THUNDERSTORMS AHEAD OF THE FRONT AS IT PUSHES NORTH
INTO/THROUGH THE AREA. THE FRONT LOOKS LIKE IT WILL PUSH NORTH OF
THE AREA BY LATE MORNING...LEAVING OUR AREA IN A WEAKLY CAPPED
ENVIRONMENT WITH WARM/HUMID AIRMASS IN PLACE. MAY HAVE TO WATCH
CLOSELY FOR SEVERE THUNDERSTORM POTENTIAL DURING THE AFTERNOON WHERE
NAM IS PRODUCING MUCAPE IN THE 3000-5000J/KG RANGE ALONG WITH 0-3KM
BULK SHEAR OF 25-30KT. NAM INSTABILITY MAY BE A BIT OVERDONE BASED
ON 70 DEGREE OUTPUT DEWPOINTS...BUT LOWER/MID 60S DEW POINTS LOOK
REALISTIC WHICH WOULD YIELD CAPE IN THE 2000-4000J/KG. LOOKS LIKE
HIGHEST SEVERE POTENTIAL WOULD BE WESTERN PORTIONS OF THE AREA WHERE
STEEPER MID-LEVEL LAPSE RATES/HIGHER-END OF THE BULK SHEAR WILL
EXIST. OTHERWISE...LOOK FOR HIGHS IN THE UPPER 70S TO THE LOWER 80S.
SHOWERS AND THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE FROM WEST
TO EAST SATURDAY NIGHT THROUGH SUNDAY AS FAIRLY STRONG SURFACE
CYCLOGENESIS TAKES PLACE OVER THE NORTHERN PLAINS...FUELING STRONGER
MOISTURE TRANSPORT/LIFT INTO THE AREA. CANNOT RULE OUT A FEW STRONG
TO SEVERE STORMS OVER WESTERN PORTIONS OF THE AREA SATURDAY NIGHT IN
DEEP SHEAR/HIGHER CAPE ENVIRONMENT. STRONG TO SEVERE STORM THREAT
CONTINUES SUNDAY AS A COLD FRONT PUSHES INTO THE AREA. EXTENT OF
SEVERE THREAT WILL BE DEPENDENT OF HOW MUCH THE ATMOSPHERE CAN
RECOVER FROM ONGOING CONVECTION AND TIMING OF THE FRONT. WILL
CONTINUE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES SUNDAY ARE
EXPECTED TO TOP OFF IN THE MIDDLE/UPPER 70S.
AFTER THIS...BEGINNING OF THE NEW WORK WEEK LOOKS COOLER/DRIER
BEHIND THE DEPARTING LOW/COLD FRONT. PLAN ON HIGHS MONDAY AND
TUESDAY IN THE UPPER 50S TO THE LOWER 60S.
SHOWER/THUNDERSTORM CHANCES SPREAD INTO THE AREA AGAIN BY WEDNESDAY
IN WARM AIR ADVECTION AHEAD OF A TROUGH PUSHING OUT OF THE PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1206 PM CDT THU MAY 14 2015
THE LIGHT RAIN HAS BEEN VERY SLOW TO ADVANCE EAST TODAY DUE TO THE
DRY AIR IN PLACE OVER WISCONSIN. THE 14.15Z HRRR INDICATES THIS
TREND WILL CONTINUE THROUGH THE AFTERNOON WITH THE LIGHT
RAIN/SPRINKLES NOT REACHING KLSE UNTIL THE MIDDLE OF THE
AFTERNOON. THERE IS ALSO A TREND IN THE HI-RES MESO MODELS THAT
THE ACTIVITY COMING UP OUT OF MISSOURI WILL BECOME THE MORE
DOMINANT AREA OF RAIN CAUSING A DRY SLOT TO DEVELOP NORTH OF IT
AND OVER THE AREA. SOME SUGGESTIONS IN THE REGIONAL RADAR DISPLAY
THAT THIS IS INDEED OCCURRING AND THAT IT WILL TAKE THE MORE
WIDESPREAD ACTIVITY OVER WESTERN IOWA TO SPREAD IN BEFORE THERE
WILL LIKELY BE ANY VISIBILITY RESTRICTIONS OCCURRING. HAVE THUS
PUSHED BACK THE TIMING OF MVFR VISIBILITY AT KLSE UNTIL EARLY THIS
EVENING BUT STILL SHOW IT BY LATE AFTERNOON AT KRST DUE MORE SO TO
SOME LIGHT FOG DEVELOPING AS THE LOW LEVELS CONTINUE TO SATURATE.
CEILINGS WILL ALSO CONTINUE TO COME DOWN WITH THIS SATURATION WITH
KRST EXPECTED TO GO TO IFR THIS AFTERNOON AND KLSE COMING DOWN TO
MVFR THIS EVENING. THE RAIN SHOULD END BY MID TO LATE EVENING WITH
BOTH SITES STAYING IFR/MVFR UNTIL FRIDAY MORNING AS THE WINDS
START TO PICK UP OUT OF THE NORTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 307 AM CDT THU MAY 14 2015
WATER VAPOR IMAGERY THIS MORNING SHOWS A VIGOROUS MID-LEVEL TROUGH
LIFTING NORTHEAST ACROSS THE PLAINS WHILE A RIDGE OF HIGH PRESSURE
EXTENDED N/S ACROSS OUR AREA. FORCING FROM THIS TROUGH WAS PRODUCING
A WIDESPREAD SWATH OF SHOWERS ACROSS EASTERN NEB/WESTERN IA...
PUSHING NORTHEAST TOWARD THE AREA. OTHERWISE...PLENTY OF HIGH/MID
CLOUD ACROSS THE FORECAST AREA WITH TEMPERATURES AT 2 AM RANGING
FROM THE LOWER/MID 40S ACROSS NORTHERN AND CENTRAL WI...TO THE
MIDDLE 50S ALONG AND WEST OF THE MISSISSIPPI RIVER.
LOOK FOR THAT MID-LEVEL TROUGH TO CONTINUE LIFTING NORTHEAST INTO
CENTRAL MN/IA BY LATE THIS AFTERNOON. GOOD AMOUNT OF 850-300MB PV-
ADVECTION AND 850MB MOISTURE TRANSPORT WILL CONTINUE TO FUEL SHOWERS
AS THEY SLOWLY PUSH INTO THE AREA FROM WEST TO EAST. DRIER LOWER
LEVELS ASSOCIATED WITH DEPARTING SURFACE HIGH PRESSURE WILL LIKELY
HOLD BULK OF THE SHOWERS WEST OF THE MISSISSIPPI RIVER THROUGH
NOON...BEFORE THEY OVERSPREAD THE REST OF THE AREA THROUGH THE
AFTERNOON HOURS. DUE TO THE CLOUDS AND INCOMING SHOWERS...
TEMPERATURES WILL SUFFER SOMEWHAT...RANGING FROM THE UPPER 50S TO
THE LOWER 60S.
SHOWERS WILL CONTINUE THROUGH MIDNIGHT ACROSS MOST OF THE
AREA...THEN START A SLOW DIMINISHING TREND FROM WEST TO EAST AFTER
MIDNIGHT AS THE TROUGH DEPARTS EAST AND RIDGING BUILDS IN FROM
MN/IA. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE UPPER 40S TO THE
MIDDLE 50S.
APPEARS RAINFALL FROM THIS SYSTEM WILL BE SOMEWHERE IN THE 1/2 TO
3/4 INCH RANGE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 307 AM CDT THU MAY 14 2015
A FEW VERY LIGHT SHOWERS MAY BE ONGOING EARLY FRIDAY MORNING EAST OF
THE MISSISSIPPI RIVER EARLY IN THE MORNING AS THE TROUGH DEPART...
BUT SKIES ARE EXPECTED TO BECOME PARTLY CLOUDY BY AFTERNOON AS A
RIDGE OF HIGH PRESSURE WORKS INTO THE AREA. PLAN ON HIGHS IN THE
UPPER 60S THE THE LOWER 70S.
FOCUS THEN SHIFTS TO THE POTENTIAL FOR SOME STRONG TO SEVERE STORMS
THROUGH THE WEEKEND.
MODELS HAVE BEEN CONSISTENT IN PUSHING A WARM FRONT NORTHWARD
INTO/ACROSS THE AREA FRIDAY NIGHT THROUGH SATURDAY. INCREASING 850MB
MOISTURE TRANSPORT INTO/OVER THE WARM FRONT IS EXPECTED TO FUEL
SCATTERED THUNDERSTORM ACTIVITY. NAM SHOWING MUCAPE OF 1500-2000J/KG
LATE FRIDAY NIGHT INTO SATURDAY MORNING WITH 0-3KM SHEAR OF 20-25KT.
SO...LOOKS LIKE WE HAVE THE POTENTIAL TO GET A FEW STRONGER/MAINLY
PULSE TYPE THUNDERSTORMS AHEAD OF THE FRONT AS IT PUSHES NORTH
INTO/THROUGH THE AREA. THE FRONT LOOKS LIKE IT WILL PUSH NORTH OF
THE AREA BY LATE MORNING...LEAVING OUR AREA IN A WEAKLY CAPPED
ENVIRONMENT WITH WARM/HUMID AIRMASS IN PLACE. MAY HAVE TO WATCH
CLOSELY FOR SEVERE THUNDERSTORM POTENTIAL DURING THE AFTERNOON WHERE
NAM IS PRODUCING MUCAPE IN THE 3000-5000J/KG RANGE ALONG WITH 0-3KM
BULK SHEAR OF 25-30KT. NAM INSTABILITY MAY BE A BIT OVERDONE BASED
ON 70 DEGREE OUTPUT DEWPOINTS...BUT LOWER/MID 60S DEW POINTS LOOK
REALISTIC WHICH WOULD YIELD CAPE IN THE 2000-4000J/KG. LOOKS LIKE
HIGHEST SEVERE POTENTIAL WOULD BE WESTERN PORTIONS OF THE AREA WHERE
STEEPER MID-LEVEL LAPSE RATES/HIGHER-END OF THE BULK SHEAR WILL
EXIST. OTHERWISE...LOOK FOR HIGHS IN THE UPPER 70S TO THE LOWER 80S.
SHOWERS AND THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE FROM WEST
TO EAST SATURDAY NIGHT THROUGH SUNDAY AS FAIRLY STRONG SURFACE
CYCLOGENESIS TAKES PLACE OVER THE NORTHERN PLAINS...FUELING STRONGER
MOISTURE TRANSPORT/LIFT INTO THE AREA. CANNOT RULE OUT A FEW STRONG
TO SEVERE STORMS OVER WESTERN PORTIONS OF THE AREA SATURDAY NIGHT IN
DEEP SHEAR/HIGHER CAPE ENVIRONMENT. STRONG TO SEVERE STORM THREAT
CONTINUES SUNDAY AS A COLD FRONT PUSHES INTO THE AREA. EXTENT OF
SEVERE THREAT WILL BE DEPENDENT OF HOW MUCH THE ATMOSPHERE CAN
RECOVER FROM ONGOING CONVECTION AND TIMING OF THE FRONT. WILL
CONTINUE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES SUNDAY ARE
EXPECTED TO TOP OFF IN THE MIDDLE/UPPER 70S.
AFTER THIS...BEGINNING OF THE NEW WORK WEEK LOOKS COOLER/DRIER
BEHIND THE DEPARTING LOW/COLD FRONT. PLAN ON HIGHS MONDAY AND
TUESDAY IN THE UPPER 50S TO THE LOWER 60S.
SHOWER/THUNDERSTORM CHANCES SPREAD INTO THE AREA AGAIN BY WEDNESDAY
IN WARM AIR ADVECTION AHEAD OF A TROUGH PUSHING OUT OF THE PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU MAY 14 2015
MAIN AVIATION CONCERNS ARE MVFR/IFR CEILING CONDITIONS AND SHOWERS
MOVING INTO THE RST/LSE TAF SITES TODAY AND CONTINUE INTO TONIGHT.
AN UPPER LEVEL DISTURBANCE OVER NORTHEAST KANSAS...NORTHWEST
MISSOURI AND SOUTHWEST IOWA WILL LIFT NORTHEAST INTO THE GREAT LAKES
REGION TONIGHT. SOUTHERLY WINDS OUT AHEAD OF THE DISTURBANCE WILL
ADVECT LOW LEVEL MOISTURE INTO THE REGION AND LOWER CEILING
HEIGHTS TODAY AT THE LSE/RST TAF SITES. THE LATEST 14.06Z NAM AND
14.09Z RAP SHOW CEILING HEIGHTS LOWERING TO IFR CONDITIONS AT RST
TAF SITE BY 21Z TODAY AND TO MVFR AT LSE BY 23Z TODAY. WITH THE
UPPER LEVEL DISTURBANCE PULLING AWAY TO THE EAST OF THE AREA AND
LIGHT RAIN/SHOWERS ENDING TONIGHT...THE LATEST 14.06Z GFS/NAM
HINT AT IMPROVING CONDITIONS AT RST/LSE TAF SITES AFTER 06Z
FRIDAY. HOWEVER...THE 14.06Z GFS/NAM BUFKIT SOUNDINGS INDICATE
NEAR SURFACE BOUNDARY LAYER RESIDUAL MOISTURE DURING THIS TIME
FRAME. WILL CONTINUE TREND OF MVFR/IFR CEILING CONDITIONS AT
RST/LSE TAF SITES AFTER 06Z FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...DTJ
AREA FORECAST DISCUSSION...CORRECTED AVIATION
NWS CHEYENNE WY
1204 PM MDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU MAY 14 2015
FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY
AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT
WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME
PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE
QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE
RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LOW LEVEL MOISTURE
IS NOT ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION
CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z.
UPPER LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE
EJECTS NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER
CALIFORNIA. WITH GOOD MID LEVEL ISENTROPIC ASCENT AND SOME
ELEVATED CAPE...THIS IS ACTUALLY A SITUATION WHERE SHOWER AND TSTM
COVERAGE COULD BE GREATER INTO THE NIGHT...ESPECIALLY OVER THE
NORTHEASTERN HALF OF THE CWA. THUS...KEPT THE 30-40 POPS GOING
THROUGH EARLY FRI MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE
TO ADVECT HIGHER DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT.
THE MOST IMPACTING EVENT IN THE SHORT TERM IS STILL LOOKING LIKE
THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI.
OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING
THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND
DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH
OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC
LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO
PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING
ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS
THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE
PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE
WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS
THIS WOULD PUSH THE SEVERE THREAT INTO SOUTHEAST WY. WHILE LARGE
HAIL WOULD LIKELY BE THE PRIMARY THREAT...THE LOW LEVEL SHEAR
PARAMETERS DO SHOW THE POTENTIAL FOR SOME WEAK TORNADOES
ESPECIALLY ALONG AND JUST NORTH OF THE WARM FRONT WHERE WINDS WILL
BE BACKED THE MOST. NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3
KM HELICITY OF 250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2
SPC OUTLOOK HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A
SLIGHT RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO
NORTH PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE
SFC LOW AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE
A BIT LESS LOW LEVEL MOISTURE AND INSTABILITY TO WORK WITH ON
SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER
LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A
COLD FRONT PUSHING ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU MAY 14 2015
AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE
TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING
SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG
/NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE
DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM
THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN
CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A
TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH
WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS
COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LOW LEVEL
UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT
SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM
RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH
BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LOW LEVEL FORCING
BENEATH INCREASINGLY DIFFLUENT FLOW ALOFT AND A COUPLED H25 JET.
THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS
FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM
ADVECTION IN LOW LEVEL EASTERLY/UPSLOPE FLOW MAKES THIS
QUESTIONABLE AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO
SEE PCPN CHANGE TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST
FOR HIGHER ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST
VIRTUALLY EVERY DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES
EACH AFTN THROUGH WED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1159 AM MDT THU MAY 14 2015
VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS THIS AFTERNOON AND
EVENING. WIDELY SCATTERED SHOWERS/TSTORMS WILL DEVELOP AFTER 20Z
ACROSS SOUTHEAST WY...WITH MORE ISOLATED OVER FAR WESTERN NE AFTER
00Z. CONVECTION MAY BE ACCOMPANIED BY GUSTY AND ERRATIC WINDS AND
LOCALIZED MVFR CIGS/VSBYS. MVFR-IFR CIGS AND MVFR VSBYS SHOULD
BECOME MORE WIDESPREAD OVER WESTERN NE AND FAR SOUTHEAST WY AFTER
09Z.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT THU MAY 14 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE
WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO
25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL
BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER
TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL
GREEN UP AFTER THE RECENT WET PERIOD.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CLH
AVIATION...MJ
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
551 AM MDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU MAY 14 2015
FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY
AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT
WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME
PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE
QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE
RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LLVL MOISTURE IS NOT
ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION CONFINED
TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z. UPPER
LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE EJECTS
NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER CALIFORNIA. WITH
GOOD MIDLVL ISENTROPIC ASCENT AND SOME ELEVATED CAPE...THIS IS
ACTUALLY A SITUATION WHERE SHOWER AND TSTM COVERAGE COULD BE
GREATER INTO THE NIGHT...ESPECIALLY OVER THE NORTHEASTERN HALF OF
THE CWA. THUS...KEPT THE 30-40 POPS GOING THROUGH EARLY FRI
MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE TO ADVECT HIGHER
DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT.
THE MOST IMPACTFUL EVENT IN THE SHORT TERM IS STILL LOOKING LIKE
THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI.
OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING
THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND
DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH
OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC
LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO
PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING
ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS
THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE
PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE
WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS
THIS WOULD PUSH THE SVR THREAT INTO SOUTHEAST WY. WHILE LARGE HAIL
WOULD LIKELY BE THE PRIMARY THREAT...THE LLVL SHEAR PARAMETERS DO
SHOW THE POTENTIAL FOR SOME WEAK TORNADOES ESPECIALLY ALONG AND
JUST NORTH OF THE WARM FRONT WHERE WINDS WILL BE BACKED THE MOST.
NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3 KM HELICITY OF
250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2 SPC OUTLOOK
HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A SLIGHT
RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO NORTH
PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE SFC LOW
AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE A BIT
LESS LLVL MOISTURE AND INSTABILITY TO WORK WITH ON
SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER
LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A
COLD FRONT PUSHING ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU MAY 14 2015
AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE
TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING
SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG
/NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE
DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM
THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN
CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A
TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH
WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS
COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LLVL
UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT
SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM
RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH
BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LLVL FORCING
BENEATH INCREASINGLY DIFLUENT FLOW ALOFT AND A COUPLED H25 JET.
THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS
FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM
ADVECTION IN LLVL EASTERLY/UPSLOPE FLOW MAKES THIS QUESTIONABLE
AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO SEE PCPN CHANGE
TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST FOR HIGHER
ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST VIRTUALLY EVERY
DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES EACH AFTN THROUGH
WED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 545 AM MDT THU MAY 14 2015
AREAS OF FOG WILL CONTINUE TO RESULT IN LOCALIZED IFR CONDITIONS
AT KAIA/KBFF THROUGH ABOUT 13-14Z. OTHERWISE VFR CONDITIONS ARE
EXPECTED AT ALL TERMINALS THROUGH MUCH OF THE DAY. SHOWER AND
TSTM CHANCES WILL INCREASE AFTER 19Z OVER SOUTHEAST WY...AND THEN
AFTER 00Z FRI OVER WESTERN NE. CONVECTION COULD BE ACCOMPANIED BY
GUSTY AND ERRATIC WINDS AND LOCALLY MVFR CIGS/VSBYS. LOW CIGS
SHOULD BECOME MORE WIDESPREAD OVER THE WESTERN PANHANDLE BETWEEN
06-12Z FRI.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT THU MAY 14 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE
WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO
25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL
BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER
TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL
GREEN UP AFTER THE RECENT WET PERIOD.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
341 AM MDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU MAY 14 2015
FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY
AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT
WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME
PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE
QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE
RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LLVL MOISTURE IS NOT
ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION CONFINED
TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z. UPPER
LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE EJECTS
NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER CALIFORNIA. WITH
GOOD MIDLVL ISENTROPIC ASCENT AND SOME ELEVATED CAPE...THIS IS
ACTUALLY A SITUATION WHERE SHOWER AND TSTM COVERAGE COULD BE
GREATER INTO THE NIGHT...ESPECIALLY OVER THE NORTHEASTERN HALF OF
THE CWA. THUS...KEPT THE 30-40 POPS GOING THROUGH EARLY FRI
MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE TO ADVECT HIGHER
DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT.
THE MOST IMPACTFUL EVENT IN THE SHORT TERM IS STILL LOOKING LIKE
THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI.
OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING
THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND
DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH
OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC
LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO
PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING
ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS
THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE
PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE
WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS
THIS WOULD PUSH THE SVR THREAT INTO SOUTHEAST WY. WHILE LARGE HAIL
WOULD LIKELY BE THE PRIMARY THREAT...THE LLVL SHEAR PARAMETERS DO
SHOW THE POTENTIAL FOR SOME WEAK TORNADOES ESPECIALLY ALONG AND
JUST NORTH OF THE WARM FRONT WHERE WINDS WILL BE BACKED THE MOST.
NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3 KM HELICITY OF
250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2 SPC OUTLOOK
HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A SLIGHT
RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO NORTH
PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE SFC LOW
AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE A BIT
LESS LLVL MOISTURE AND INSTABILITY TO WORK WITH ON
SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER
LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A
COLD FRONT PUSHING ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU MAY 14 2015
AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE
TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING
SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG
/NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE
DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM
THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN
CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A
TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH
WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS
COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LLVL
UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT
SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM
RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH
BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LLVL FORCING
BENEATH INCREASINGLY DIFLUENT FLOW ALOFT AND A COUPLED H25 JET.
THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS
FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM
ADVECTION IN LLVL EASTERLY/UPSLOPE FLOW MAKES THIS QUESTIONABLE
AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO SEE PCPN CHANGE
TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST FOR HIGHER
ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST VIRTUALLY EVERY
DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES EACH AFTN THROUGH
WED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 214 AM MDT THU MAY 14 2015
AMENDED AVIATION DISCUSSION FOR 06Z TAFS. AREAS OF FOG ARE NOW
DEVELOPING OVER THE WESTERN NE PANHANDLE...WITH IFR CIGS/VSBYS
OVER SEVERAL TERMINALS. THE HRRR SHOWS THIS CONTINUING THROUGH
AT LEAST SUNRISE...LINGERING A BIT LONGER AT KAIA. VFR CONDITIONS
ARE EXPECTED OVER SOUTHEAST WYOMING SITES. SHOWERS AND TSTMS ARE
STILL EXPECTED ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT THU MAY 14 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE
WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO
25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL
BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER
TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL
GREEN UP AFTER THE RECENT WET PERIOD.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
216 AM MDT THU MAY 14 2015
.UPDATE...
ISSUED AT 906 PM MDT WED MAY 13 2015
AS OUR AFTERNOON FORECAST TEAM PREDICTED...SHOWERS HAVE DECREASED
CONSIDERABLY IN AREAL COVERAGE. BASED ON TRENDS AND 00Z MODEL
GUIDANCE...WILL MAINTAIN LOW CHANCES FOR PRECIPITATION THE REST
OF THE NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 400 PM MDT WED MAY 13 2015
SHORTWAVE ENERGY AND UPPER LEVEL JET MAX WILL CONTINUE TO LIFT
NORTHEAST OUT OF THE FORECAST AREA THIS EVENING WITH MOST SHOWER
ACTIVITY ENDING WEST OF THE SHORTWAVE AND JET. A FEW SHOWERS MAY
LINGER PAST 9 PM BUT MOST ACTIVITY SHOULD HAVE ENDED BY THAT
TIME. TO THE WEST OF THE LARAMIE RANGE SHOWER ACTIVITY IS LARGELY
BEING DRIVEN BY INSTABILITY. THIS AREAS OF SHOWER ACTIVITY WILL
ALSO TAPER OFF THIS EVENING.
SUBSIDENCE WILL ALLOW SET IN THIS EVENING AS A RIDGE BUILDS OVER
THE NORTHERN ROCKIES. SKIES WILL CLEAR AND WINDS WILL BE ON THE
LIGHT SIDE TONIGHT. SOME POCKETS OF RADIATION FOG MAY DEVELOP LATE
TONIGHT. NOT EXPECTING LARGE IMPACTS FROM ANY FOG TONIGHT THAT
MIGHT FORM BUT IT WILL BE SOMETHING TO KEEP AN EYE ON LATE
TONIGHT...MAINLY WEST OF THE LARAMIE RANGE.
A BROAD WEST COAST TROUGH WILL BEGIN TO PUSH INTO THE ROCKIES LATE
TOMORROW AS THE RIDGE AXIS SHIFTS INTO THE PLAINS. A FEW SHOWERS
AND THUNDERSTORMS WILL DEVELOP THURSDAY AFTERNOON. THE SET UP IS
NOT SUPPORTIVE OF SEVERE THUNDERSTORMS BUT A FEW MARGINAL STORMS
NOT COMPLETELY QUESTION NEAR THE LARAMIE RANGE LATE AFTERNOON.
UPPER LEVEL ENERGY WITH ISENTROPIC FORCING WILL KEEP CHANCES FOR
SHOWERS AND A FEW THUNDERSTORMS GOING INTO THURSDAY NIGHT BUT THE
MAIN CHANCES FOR PRECIPITATION WILL HOLD OFF UNTIL FRIDAY. WILL
NEED TO KEEP A CLOSE EYE ON SEVERE THUNDERSTORM POTENTIAL INTO THE
PLAINS FRIDAY. THERE IS STILL A LOT OF UNCERTAINLY IN THE
PLACEMENT OF A WARM FRONT AND TIMING OF COLD FRONT FRIDAY. MODELS
ARE SHOWING A LOT OF ELEVATED CAPE AND ENOUGH SHEAR FOR SUPERCELL
THUNDERSTORMS. NORTH OF THE WARM FRONT LARGE HAIL WILL BE THE MAIN
SEVERE THUNDERSTORM THREAT BUT ALONG AND CLOSE TO THE SURFACE WARM
FRONT THERE WILL LIKELY BE AN ELEVATED TORNADO THREAT. WILL
CONTINUE TO MONITOR MODEL CHANGES BUT AT THIS TIME IT LOOKS AT
THROUGH THE SURFACE FRONT WILL EXTEND ACROSS THE NORTHERN NEBRASKA
PANHANDLE FRIDAY AFTERNOON.
.LONG TERM...SATURDAY THROUGH TUESDAY...
ISSUED AT 400 PM MDT WED MAY 13 2015
MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT WITH LARGELY MERIDIONAL
FLOW ALOFT THROUGH THE PERIOD. THIS SHOULD RESULT IN A FAIRLY ACTIVE
WEATHER PERIOD FOR SOUTHEAST WYO AND THE WESTERN NEB PANHANDLE THRU
THE WEEKEND AND INTO EARLY NEXT WEEK. THE WEEKEND STILL APPEARS TO
BE RATHER WET WITH A COMPLEX NEGATIVELY TILTED SHORTWAVE MOVING EAST
ONTO THE PLAINS ON SAT. BOTH THE GFS AND ECMWF BRING AN ASSOCIATED
DOUBLE-BARRELED SURFACE LOW INTO SD/NE...WITH WRAPAROUND PCPN
LIKELY SPREADING ACROSS THE CWA. WEAK CAPES SUGGEST CONVECTION
WILL BE AT A MINIMUM...BUT COOL AIR ALOFT MAY YIELD ENOUGH
INSTABILITY FOR A FEW LIGHTNING STRIKES AND POSSIBLY SMALL HAIL.
THERE IS SOME POTENTIAL FOR ACCUMULATING SNOWFALL IN THE HIGH
MOUNTAINS ABOVE 9K FEET ON SAT AND SUN WITH FAVORABLE OROGRAPHICS
AND H7 TEMPS FALLING TO -2 DEG C OR LOWER PER THE ECMWF. EXPECT
THIS TO BE SUB-ADVISORY. A TRANSITORY RIDGE PROVIDES A BRIEF BREAK
ON SUN NIGHT INTO MON BEFORE STRONG SW FLOW ALOFT INCREASES AGAIN
AHEAD OF THE NEXT SYSTEM OVER SOUTHERN CALIFORNIA. SOME
DIFFERENCES IN MODEL QPF/PCPN COVERAGE HEADING INTO TUES...WITH
THE ECMWF SHOWING MUCH MORE WIDESPREAD SHOWERS AND TSTMS WITH LLVL
UPSLOPE DEVELOPING ALONG THE LARAMIE RANGE. THE GFS TURNS WINDS
WESTERLY/DOWNSLOPE AS IT MOVES THE SURFACE TROUGH QUICKLY INTO
WESTERN NEB. INCREASED POPS ABOVE GUIDANCE WITH BOTH THE GFS AND
ECM SHOWING STRONG UPPER DIFFLUENCE. WOULD TEND TO LEAN TOWARD
THE ECMWF WITH SOUTHERLY MID/UPPER-LEVEL FLOW KEEPING THE SURFACE
FEATURE TIED TO THE LARAMIE RANGE AS WELL. BOTH MODELS SUGGEST
UPWARDS OF 1500 J/KG OF CAPE ON THE EAST SIDE OF THE BOUNDARY...SO
THE POTENTIAL FOR STRONG CONVECTION SHOULD BE ON THE UPTICK COME
TUE AFTN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 214 AM MDT THU MAY 14 2015
AMENDED AVIATION DISCUSSION FOR 06Z TAFS. AREAS OF FOG ARE NOW
DEVELOPING OVER THE WESTERN NE PANHANDLE...WITH IFR CIGS/VSBYS
OVER SEVERAL TERMINALS. THE HRRR SHOWS THIS CONTINUING THROUGH
AT LEAST SUNRISE...LINGERING A BIT LONGER AT KAIA. VFR CONDITIONS
ARE EXPECTED OVER SOUTHEAST WYOMING SITES. SHOWERS AND TSTMS ARE
STILL EXPECTED ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 331 PM MDT WED MAY 13 2015
CONDITIONS WILL REMAIN ON THE COOL SIDE OF AVERAGE OVER THE NEXT 7 DAYS
AS AN ACTIVE WEATHER PATTERN REMAINS IN PLACE. THERE WILL BE A CHANCE
FOR SHOWERS AND A FEW THUNDERSTORMS SEVERAL DAYS DURING THIS PERIOD.
THERE ARE NO CRITICAL FIRE CONCERNS.
&&
.HYDROLOGY...
ISSUED AT 331 PM MDT WED MAY 13 2015
THE LARAMIE RIVER NEAR LARAMIE WILL CONTINUE TO RUN HIGH THE NEXT
SEVERAL DAYS...BUT ASSUMING FORECAST PRECIPITATION AMOUNTS ARE
CLOSE TO CORRECT...THEN THE RIVER WILL REMAIN BELOW FLOOD STAGE.
TEMPERATURES WILL REMAIN AT TO BELOW NORMAL OVER THE NEXT
WEEK...SO AS LONG AND STRONG THUNDERSTORMS DO NOT OCCUR OVER THE
MOUNTAINS...SNOW PACK WILL SLOWLY COME OFF THE MOUNTAINS WITH NO
BIG CONCERNS FOR RIVER FLOODING OVER THE NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...RUBIN
SHORT TERM...SML
LONG TERM...CAH
AVIATION...CLH
FIRE WEATHER...SML
HYDROLOGY...SML
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1147 PM MDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 543 PM MDT FRI MAY 15 2015
QUICK UPDATE TO BOOST POPS ACROSS MUCH OF THE FORECAST AREA FOR
THE NEXT SEVERAL HOURS. LATEST HRRR AND 18Z RUNS A LITTLE MORE
AGGRESSIVE OVERNIGHT AND WILL TREND POPS IN THIS DIRECTION. MINOR
WIGGLES OR WAVES IN THE FLOW WILL CONTINUE TO SPARK AREAS OF
SHOWERS WITH PERIODS OF NULL WEATHER ALSO EXPECTED THROUGH THE
OVERNIGHT HOURS.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 352 PM MDT FRI MAY 15 2015
THE LOW PRESSURE SYSTEM OVER THE GREAT BASIN WILL VERY GRADUALLY
SHIFT TO THE NORTHEAST TONIGHT AND CENTER ITS MAIN CORE OVER
NORTHERN UTAH AT 500MB BY THE EARLY MORNING HOURS...WITH A WEAK
CENTER OF CIRCULATION NEAR THE 4 CORNERS EMBEDDED IN THE GENERAL
PATTERN AT THIS SAME TIME. THIS SYSTEM IS BROADLY ORGANIZED AND
BECAUSE OF THAT...POCKETS OF NO SIGNIFICANT WEATHER AND POCKETS OF
MODERATE TO HEAVY PRECIPITATION WILL OCCUR. CURRENT SATELLITE
IMAGERY INDICATES AN AREA OF GOOD UPLIFT OVER THE PAGOSA
SPRINGS/WOLF CREEK REGION. NE UTAH AND NW COLORADO ARE
TRANSITIONING INTO A MORE STABLE AREA SO WILL SEE A BREAK FOR
ABOUT 6 TO 12 HOURS THIS EVENING WITH THE OCCASIONAL ISOLATED SHOWER
ABLE TO DEVELOP. COLD AIR IS ADVECTING INTO THE REGION WITH SNOW
LEVEL EXPECTED TO DROP THROUGHOUT THE EVENING. GOOD VERTICAL
VELOCITY FORECAST FOR THE FOUR CORNERS TONIGHT BETWEEN 5PM THIS
EVENING THROUGH TOMORROW MORNING SO WILL EXPECT PRECIPITATION TO
PICK UP THIS EVENING IN THIS AREA WITH EFFICIENT PRECIPITATION
RATES...AND SNOW DOWN TO 7500 FEET AND FALLING BY MIDNIGHT.
ANOMALOUSLY STRONG CLOSED LOW EJECTS NORTHEAST ACROSS THE WESTERN
SLOPE ON SATURDAY. THE COLDEST AIR AND DYNAMICAL LIFT OCCURS WITH
THIS FEATURE. THE BEST QPF WILL BE FOCUSED OVER THE SAN JUAN
MOUNTAINS...ALTHOUGH THE WRN CO MOUNTAINS WILL GET A FAIR AMOUNT
TONIGHT AND SATURDAY MORNING.
A SECONDARY SHORT WAVE ROTATES INTO WRN COLORADO SATURDAY NIGHT.
ALTHOUGH THIS SHORT WAVE ARRIVES FROM THE NORTHWEST...MODEL DATA
SHOWS BRIEF MID LEVEL COLD ADVECTION SATURDAY EVENING (BUT NOT ANY
COLDER THAN THE MAIN COLD CORE TONIGHT/SATURDAY). SNOW LEVELS
WILL NOT FALL ANY LOWER THAN OCCURS SATURDAY MORNING...POSSIBLY
BECOME SLIGHTER HIGHER GIVEN SLIGHTLY WARMER AIR AND LOWER QPF
RATES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 352 PM MDT FRI MAY 15 2015
SOME SHORT LIVED TERRAIN DRIVEN CONVECTIVE SHOWERS WILL OCCUR
SUNDAY AFTERNOON...OTHERWISE A BRIEF RESPITE FROM THE RAIN OR
SNOW. BUT THE NEXT PACIFIC CLOSED LOW BARRELS INTO CALIFORNIA ON
MONDAY. A NEGATIVELY TILTED SHORT WAVE EJECTS ACROSS THE FORECAST
AREA MONDAY NIGHT AND TUESDAY. LIKE THE CURRENT WEATHER
SYSTEM...THIS GENERATES ANOTHER HEALTHY DOSE OF SHOWERS/STORMS
WITH A FAIR AMOUNT OF RAINFALL. THIS WILL BE A WARMER SYSTEM AND
SNOW WILL BE LIMITED TO ABOVE TIMBERLINE...MAYBE SNOW LEVELS
LOWERING TO THE MOUNTAIN PASSES.
DRIER SOUTHWEST FLOW PREVAILS OVER THE FOUR CORNERS REGION FOR THE
WEDNESDAY THROUGH FRIDAY TIME FRAME. SOME DIURNAL CONVECTIVE
SHOWERS MAY STILL FORM OVER THE MOUNTAIN AREAS...BUT THESE WILL
NOT BE LONG LASTING AND PRODUCE LIGHT RAIN AMOUNTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1126 PM MDT FRI MAY 15 2015
THIS VERY WET SYSTEM WILL CONTINUE TO IMPACT FLIGHT OPERATIONS
ACROSS EASTERN UTAH AND WESTERN COLORADO OVER THE NEXT 24 HOURS.
THREATS WILL BE LOWERED FLIGHT CRITERIA AND OCCASIONAL LIGHTNING
DURING THE AFTERNOON AND EVENING TIME PERIODS FROM PASSING
THUNDERSTORMS. MOST VALLEY LOCATIONS WILL BE ABLE TO SUSTAIN VFR
CONDITIONS BUT TEMPORARY MVFR WILL BE POSSIBLE IN PASSING SHOWERS.
AT THE MOUNTAIN TERMINALS SITES INCLUDING KASE...KTEX AND POSSIBLY
KEGE...IFR CONDITIONS WILL ALSO BE POSSIBLE WITH REDUCTION TO BOTH
VSBY AND CIGS COMING FROM SNOWFALL THROUGH 17/06Z.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ009-010-
012-018-019.
WINTER STORM WARNING UNTIL 9 AM MDT SUNDAY FOR COZ009-010-012-
018-019.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR
COZ017.
WINTER WEATHER ADVISORY UNTIL 9 AM MDT SUNDAY FOR COZ004-013.
UT...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR
UTZ028.
&&
$$
UPDATE...JDC
SHORT TERM...JAM/PF
LONG TERM...PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS ALBANY NY
159 AM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
OVERNIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND
ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION
SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY
AND WARM WEATHER SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUD COVER CONTINUES TO LOWER WITH SHOWERS DEVELOPING AND MOVING
INTO THE FORECAST AREA AHEAD OF THE APPROACHING WARM FRONT/LOW
PRESSURE SYSTEM AND UPPER LEVEL SHORT WAVE TROUGH. SHOWERS HAVE
BEEN VERY LIGHT THUS FAR AS THE ATMOSPHERE IS RATHER DAY AS NOTED
BY THE VERY DRY LAYER FROM 1000-700 MB ON THE 00Z/ALY SOUNDING.
HRRR SHOWS SHOWERS MOVING ACROSS THE AREA THROUGH THE EARLY
MORNING HOURS. USED REGIONAL RADARS AND HRRR TO ADJUST POPS. THERE
HAS BEEN A FEW LIGHTNING STRIKES ACROSS CENTRAL NEW YORK WHICH
LINES UP FAIRLY WELL WITH THE MODELED SHOWALTER INDICES. THE
-2 TO ZERO INDICES MOVES ACROSS THE SOUTHERN PORTION OF THE
FORECAST AREA...USED THIS AS A GUIDE WHERE TO MENTION SLIGHT
CHANCE OF THUNDER FOR THE OVERNIGHT/EARLY MORNING HOURS.
OVERALL DID ADJUST TEMPERATURES UP A BIT...HAVE LOWS MAINLY IN THE
50S WITH SOME 40S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN
ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS INTO THE NORTHERN
BERKSHIRES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
THE WARM FRONT WILL CROSS THE REGION SATURDAY MORNING AND THAT
SHOULD BRING TO AN END ANY STEADY RAINFALL THAT MAY OCCUR AHEAD OF
IT. A WEAK COLD FRONT AND SOME DRIER AIR WILL TRY TO PUSH
SOUTHWARD INTO THE REGION SATURDAY AFTN AND NIGHT. IT WILL NOT BE
SOUTH OF THE REGION UNTIL EARLY SUNDAY MORNING. AS A RESULT...
THERE WILL STILL BE A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
SATURDAY AFTN AND NIGHT...ESPECIALLY AREAS SOUTH OF ALBANY. HAVE
GENERALLY FORECAST 20 TO 30 PERCENT POPS FROM THE CAPITAL DISTRICT
NORTH DURING SATURDAY AFTERNOON...AND 30 TO 40 PERCENT POPS TO
THE SOUTH. THESE POPS CONTINUE TO DECREASE SATURDAY NIGHT WITH
MOST OF THE REGION DRY BY SUNRISE SUNDAY.
THE DRIER AIR BEHIND THIS WEAK COLD FRONT WILL RESULT IN FAIR AND
WARM WEATHER SUNDAY AND SUNDAY NIGHT.
HIGHS SATURDAY WILL BE IN THE UPPER 60S AND 70S. LOWS SATURDAY
NIGHT GENERALLY 50 TO 60. HIGHS SUNDAY 75 TO 85. LOWS SUNDAY NIGHT IN
THE UPPER 40S AND 50S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE LONG TERM PERIOD WILL BEGIN SOMEWHAT UNSETTLED...BEFORE FAIR
WEATHER AND COOLER TEMPERATURES DOMINATE FOR THE BULK OF THE
REMAINDER OF THE LONG TERM.
FOR MON...A SHARP UPPER LEVEL RIDGE WILL CREST OVER THE REGION
BEFORE MOVING OFF THE NEW ENGLAND COAST LATE IN THE DAY. AT THE
SFC...A BACKDOOR COLD FRONTAL BOUNDARY SHOULD START OUT ACROSS
CENTRAL NYS...POSSIBLY EXTREME WESTERN AREAS OF THE REGION IN THE
MORNING. THIS BOUNDARY SHOULD WEAKEN...BEFORE DRIFTING BACK EAST
LATER IN THE DAY. ALSO...A MUCH STRONGER COLD FRONT WILL BE
APPROACHING FROM THE GREAT LAKES REGION. IT APPEARS THAT SHOWERS
SHOULD SLOWLY EXPAND EASTWARD ACROSS THE REGION DURING THE DAY.
HOWEVER...GIVEN THE SHARPNESS OF THE UPPER LEVEL RIDGE...IT IS QUITE
POSSIBLE THAT AREAS EAST OF THE HUDSON RIVER REMAIN DRY THROUGH
SUNSET. SO...WILL ONLY GRADUALLY INCREASE POPS INTO THE CHC RANGE
FOR WESTERN AREAS...AND MAINLY SLIGHT CHC FOR EASTERN AREAS BY LATE
IN THE DAY...WITH MAINLY DRY CONDITIONS FOR ALL AREAS IN THE
MORNING. TEMPERATURES WILL BE WARMEST ACROSS THE SOUTHERN
ADIRONDACKS AND WESTERN MOHAWK RIVER VALLEY...WHERE TEMPS NEAR 80
ARE EXPECTED. ELSEWHERE...A MARINE MODIFIED AIR MASS SHOULD RESULT
IN SLIGHTLY COOLER TEMPS FURTHER SOUTH AND EAST...WITH GENERALLY 70S
FOR VALLEYS...AND UPPER 60S/LOWER 70S ACROSS HIGHER ELEVATIONS.
MON NT-TUE...THE COLD FRONT ACROSS THE GREAT LAKES REGION SHOULD
SLOWLY SWING EAST ACROSS THE REGION. THIS SHOULD RESULT IN SOME
ROUNDS OF SHOWERS AND POSSIBLE THUNDERSTORMS. THE BEST CHANCE FOR
SIGNIFICANT RAINFALL WILL BE ACROSS THE SOUTHERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY...WHICH WILL BE CLOSER TO THE PASSING UPPER
LEVEL DYNAMICS. SHOWERS MAY TEND TO BECOME MORE SCATTERED FOR AREAS
SOUTH AND EAST OF ALBANY. DEPENDING ON THE SPEED OF THE
FRONT...SHOWERS MAY TEND TO TAPER OFF FROM NW TO SE TUE AFTERNOON.
ALTHOUGH MID/UPPER LEVEL WINDS WILL STRENGTHEN...AT THIS TIME...MID
LEVEL LAPSE RATES DO NOT APPEAR VERY STRONG...SO AT LEAST AT THIS
TIME RANGE...IT APPEARS THAT THE OVERALL THREAT FOR WIDESPREAD
STRONG/SEVERE THUNDERSTORMS SHOULD BE LOW. MON NT/TUE AM MIN TEMPS
SHOULD BE MILD...MAINLY IN THE 50S TO LOWER 60S. TUE MAX TEMPS ARE
TRICKY...DEPENDING ON HOW MUCH SUN CAN BREAK OUT. ASSUMING CLOUDS
REMAIN FAIRLY WIDESPREAD...CURRENT FORECAST MAX TEMPS ARE IN THE 70-
75 RANGE IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. HOWEVER...IF
THE FRONT SLOWS DOWN AND SOME BREAKS CAN DEVELOP...MUCH WARMER MAXES
COULD OCCUR.
TUE NT-FRI...LARGE HIGH PRESSURE SHOULD SLOWLY BUILD ACROSS THE
REGION FROM THE GREAT LAKES. MOST LONG TERM GUIDANCE SUGGESTS
ANOMALOUSLY COOL MID/UPPER LEVEL HEIGHTS AND CORRESPONDING H925-850
TEMPS. THERE COULD BE SPOTTY SHOWERS/SPRINKLES IN ASSOCIATION WITH
THE UPPER LEVEL COLD POOL AND EVEN SOME WEAK LAKE EFFECT PROCESSES
FOR TUE NT-WED ACROSS THE SOUTHWEST ADIRONDACKS. OTHERWISE...TEMPS
WILL BE QUITE COOL WED...WITH MAXES ONLY REACHING 60-65 IN
VALLEYS...AND 50S FOR MOST HIGHER ELEVATIONS...ALTHOUGH SOME OF THE
HIGHEST PEAKS OF THE SOUTHERN ADIRONDACKS AND SOUTHERN VT MAY ONLY
REMAIN IN THE 40S. OVERNIGHT MIN TEMPS FOR TUE NT/WED AM WILL MAINLY
BE IN THE 40S TO LOWER 50S. FOR WED NT/THU AM...MIN TEMPS SHOULD BE
EVEN COOLER...WITH 30S ACROSS THE WESTERN ADIRONDACKS...AND 40S
ELSEWHERE. THERE COULD BE SOME FROST ACROSS PORTIONS OF THE SOUTHERN
ADIRONDACKS...WHERE THE GROWING SEASON BEGINS MAY 21. THU AND FRI
MAX TEMPS SHOULD WARM SLIGHTLY...WITH LOWER 70S IN VALLEYS AND 60S
ACROSS HIGHER ELEVATIONS. MIN TEMPS FOR THU NT/FRI AM SHOULD FALL
INTO THE 40S FOR MOST AREAS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A WARM FRONT WILL MOVE ACROSS ERN NY AND WRN NEW ENGLAND LATE THIS
MORNING INTO THE EARLY AFTERNOON. THE REGION WILL BE IN A WARM
SECTOR BRIEFLY LATE THIS AFTERNOON INTO THE EARLY EVENING. A COLD
FRONT WILL MOVE THROUGH TONIGHT...BEFORE HIGH PRESSURE RIDGES IN
FOR SUNDAY.
VFR CONDITIONS THIS MORNING WILL LOWER TO HIGH MVFR LEVELS IN
TERMS OF VSBYS/CIGS WITH THE SHOWERS AHEAD OF THE WARM FRONT.
THERE MAYBE A BRIEF RUMBLE OF THUNDER...BUT SINCE IT IS ISOLATED
NO THUNDERSTORMS WERE ADDED TO THE TAF SITES AT THIS TIME. THE
BEST CHC OF MVFR CIGS/VSBYS WILL BE BTWN 08Z-14Z. THE CONDITIONS
WILL INCREASE BACK TO VFR LEVELS AFTER THE SHOWERS. SCT-BKN
CUMULUS AND MID LEVEL CLOUDINESS WILL LINGER IN THE LATE MORNING
INTO THE AFTERNOON.
THE COLD FRONT AND A PREFRONTAL DISTURBANCE WILL APPROACH LATE IN
THE PM INTO THE EARLY EVENING. A VCSH GROUP WAS PLACED IN
KGFL/KALB/KPOU/KPSF IN THE 21Z-23Z TIME FRAME. LATER TAF ISSUANCES
MAY HAVE TO ADD THUNDERSTORMS IF CONFIDENCE INCREASES.
THE WINDS WILL BE LIGHT FROM THE S TO SE AT 5 KTS OR LESS THAN
MORNING...THEN INCREASE FROM THE S AT 5-10 KTS IN THE LATE MORNING
INTO THE AFTERNOON.
OUTLOOK...
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY NIGHT: ISOLATED SHRA.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
TONIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED
THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY...
AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM
WEATHER SUNDAY INTO MONDAY.
WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND RH VALUES WILL BE 90
TO 100 PERCENT. WINDS WILL BECOME SOUTHWEST SATURDAY AT 10 TO 15
MPH WITH RH 50 TO 60 PERCENT. RAINFALL TONIGHT AND SATURDAY MAY
PRODUCE UP TO A QUARTER TO A THIRD OF INCH. DRY WEATHER IS
EXPECTED SUNDAY AND MONDAY.
&&
.HYDROLOGY...
THE NEXT CHANCE OF SHOWERS WILL BE TONIGHT INTO SATURDAY...WITH
RAINFALL AMOUNTS EXPECTED TO BE AROUND A QUARTER TO A THIRD OF AN
INCH. THIS WILL HAVE LITTLE IMPACT ON AREA RIVERS AND STREAMS.
ONLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED SATURDAY AFTERNOON
AND NIGHT...WITH MAINLY DRY WEATHER EXPECTED FOR SUNDAY.
ANOTHER ROUND OF RAIN IS LIKELY LATE MONDAY INTO TUESDAY WITH THE
POTENTIAL FOR ANOTHER QUARTER TO THIRD OF AN INCH.
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...IAA/GJM
NEAR TERM...IAA/KL/GJM/LFM
SHORT TERM...GJM
LONG TERM...KL
AVIATION...WASULA
FIRE WEATHER...GJM
HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS ALBANY NY
139 AM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
OVERNIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND
ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION
SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY
AND WARM WEATHER SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUD COVER CONTINUES TO LOWER WITH SHOWERS DEVELOPING AND MOVING
INTO THE FORECAST AREA AHEAD OF THE APPROACHING WARM FRONT/LOW
PRESSURE SYSTEM AND UPPER LEVEL SHORT WAVE TROUGH. SHOWERS HAVE
BEEN VERY LIGHT THUS FAR AS THE ATMOSPHERE IS RATHER DAY AS NOTED
BY THE VERY DRY LAYER FROM 1000-700 MB ON THE 00Z/ALY SOUNDING.
HRRR SHOWS SHOWERS MOVING ACROSS THE AREA THROUGH THE EARLY
MORNING HOURS. USED REGIONAL RADARS AND HRRR TO ADJUST POPS. THERE
HAS BEEN A FEW LIGHTNING STRIKES ACROSS CENTRAL NEW YORK WHICH
LINES UP FAIRLY WELL WITH THE MODELED SHOWALTER INDICES. THE
-2 TO ZERO INDICES MOVES ACROSS THE SOUTHERN PORTION OF THE
FORECAST AREA...USED THIS AS A GUIDE WHERE TO MENTION SLIGHT
CHANCE OF THUNDER FOR THE OVERNIGHT/EARLY MORNING HOURS.
OVERALL DID ADJUST TEMPERATURES UP A BIT...HAVE LOWS MAINLY IN THE
50S WITH SOME 40S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN
ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS INTO THE NORTHERN
BERKSHIRES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
THE WARM FRONT WILL CROSS THE REGION SATURDAY MORNING AND THAT
SHOULD BRING TO AN END ANY STEADY RAINFALL THAT MAY OCCUR AHEAD OF
IT. A WEAK COLD FRONT AND SOME DRIER AIR WILL TRY TO PUSH
SOUTHWARD INTO THE REGION SATURDAY AFTN AND NIGHT. IT WILL NOT BE
SOUTH OF THE REGION UNTIL EARLY SUNDAY MORNING. AS A RESULT...
THERE WILL STILL BE A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
SATURDAY AFTN AND NIGHT...ESPECIALLY AREAS SOUTH OF ALBANY. HAVE
GENERALLY FORECAST 20 TO 30 PERCENT POPS FROM THE CAPITAL DISTRICT
NORTH DURING SATURDAY AFTERNOON...AND 30 TO 40 PERCENT POPS TO
THE SOUTH. THESE POPS CONTINUE TO DECREASE SATURDAY NIGHT WITH
MOST OF THE REGION DRY BY SUNRISE SUNDAY.
THE DRIER AIR BEHIND THIS WEAK COLD FRONT WILL RESULT IN FAIR AND
WARM WEATHER SUNDAY AND SUNDAY NIGHT.
HIGHS SATURDAY WILL BE IN THE UPPER 60S AND 70S. LOWS SATURDAY
NIGHT GENERALLY 50 TO 60. HIGHS SUNDAY 75 TO 85. LOWS SUNDAY NIGHT IN
THE UPPER 40S AND 50S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE LONG TERM PERIOD WILL BEGIN SOMEWHAT UNSETTLED...BEFORE FAIR
WEATHER AND COOLER TEMPERATURES DOMINATE FOR THE BULK OF THE
REMAINDER OF THE LONG TERM.
FOR MON...A SHARP UPPER LEVEL RIDGE WILL CREST OVER THE REGION
BEFORE MOVING OFF THE NEW ENGLAND COAST LATE IN THE DAY. AT THE
SFC...A BACKDOOR COLD FRONTAL BOUNDARY SHOULD START OUT ACROSS
CENTRAL NYS...POSSIBLY EXTREME WESTERN AREAS OF THE REGION IN THE
MORNING. THIS BOUNDARY SHOULD WEAKEN...BEFORE DRIFTING BACK EAST
LATER IN THE DAY. ALSO...A MUCH STRONGER COLD FRONT WILL BE
APPROACHING FROM THE GREAT LAKES REGION. IT APPEARS THAT SHOWERS
SHOULD SLOWLY EXPAND EASTWARD ACROSS THE REGION DURING THE DAY.
HOWEVER...GIVEN THE SHARPNESS OF THE UPPER LEVEL RIDGE...IT IS QUITE
POSSIBLE THAT AREAS EAST OF THE HUDSON RIVER REMAIN DRY THROUGH
SUNSET. SO...WILL ONLY GRADUALLY INCREASE POPS INTO THE CHC RANGE
FOR WESTERN AREAS...AND MAINLY SLIGHT CHC FOR EASTERN AREAS BY LATE
IN THE DAY...WITH MAINLY DRY CONDITIONS FOR ALL AREAS IN THE
MORNING. TEMPERATURES WILL BE WARMEST ACROSS THE SOUTHERN
ADIRONDACKS AND WESTERN MOHAWK RIVER VALLEY...WHERE TEMPS NEAR 80
ARE EXPECTED. ELSEWHERE...A MARINE MODIFIED AIR MASS SHOULD RESULT
IN SLIGHTLY COOLER TEMPS FURTHER SOUTH AND EAST...WITH GENERALLY 70S
FOR VALLEYS...AND UPPER 60S/LOWER 70S ACROSS HIGHER ELEVATIONS.
MON NT-TUE...THE COLD FRONT ACROSS THE GREAT LAKES REGION SHOULD
SLOWLY SWING EAST ACROSS THE REGION. THIS SHOULD RESULT IN SOME
ROUNDS OF SHOWERS AND POSSIBLE THUNDERSTORMS. THE BEST CHANCE FOR
SIGNIFICANT RAINFALL WILL BE ACROSS THE SOUTHERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY...WHICH WILL BE CLOSER TO THE PASSING UPPER
LEVEL DYNAMICS. SHOWERS MAY TEND TO BECOME MORE SCATTERED FOR AREAS
SOUTH AND EAST OF ALBANY. DEPENDING ON THE SPEED OF THE
FRONT...SHOWERS MAY TEND TO TAPER OFF FROM NW TO SE TUE AFTERNOON.
ALTHOUGH MID/UPPER LEVEL WINDS WILL STRENGTHEN...AT THIS TIME...MID
LEVEL LAPSE RATES DO NOT APPEAR VERY STRONG...SO AT LEAST AT THIS
TIME RANGE...IT APPEARS THAT THE OVERALL THREAT FOR WIDESPREAD
STRONG/SEVERE THUNDERSTORMS SHOULD BE LOW. MON NT/TUE AM MIN TEMPS
SHOULD BE MILD...MAINLY IN THE 50S TO LOWER 60S. TUE MAX TEMPS ARE
TRICKY...DEPENDING ON HOW MUCH SUN CAN BREAK OUT. ASSUMING CLOUDS
REMAIN FAIRLY WIDESPREAD...CURRENT FORECAST MAX TEMPS ARE IN THE 70-
75 RANGE IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. HOWEVER...IF
THE FRONT SLOWS DOWN AND SOME BREAKS CAN DEVELOP...MUCH WARMER MAXES
COULD OCCUR.
TUE NT-FRI...LARGE HIGH PRESSURE SHOULD SLOWLY BUILD ACROSS THE
REGION FROM THE GREAT LAKES. MOST LONG TERM GUIDANCE SUGGESTS
ANOMALOUSLY COOL MID/UPPER LEVEL HEIGHTS AND CORRESPONDING H925-850
TEMPS. THERE COULD BE SPOTTY SHOWERS/SPRINKLES IN ASSOCIATION WITH
THE UPPER LEVEL COLD POOL AND EVEN SOME WEAK LAKE EFFECT PROCESSES
FOR TUE NT-WED ACROSS THE SOUTHWEST ADIRONDACKS. OTHERWISE...TEMPS
WILL BE QUITE COOL WED...WITH MAXES ONLY REACHING 60-65 IN
VALLEYS...AND 50S FOR MOST HIGHER ELEVATIONS...ALTHOUGH SOME OF THE
HIGHEST PEAKS OF THE SOUTHERN ADIRONDACKS AND SOUTHERN VT MAY ONLY
REMAIN IN THE 40S. OVERNIGHT MIN TEMPS FOR TUE NT/WED AM WILL MAINLY
BE IN THE 40S TO LOWER 50S. FOR WED NT/THU AM...MIN TEMPS SHOULD BE
EVEN COOLER...WITH 30S ACROSS THE WESTERN ADIRONDACKS...AND 40S
ELSEWHERE. THERE COULD BE SOME FROST ACROSS PORTIONS OF THE SOUTHERN
ADIRONDACKS...WHERE THE GROWING SEASON BEGINS MAY 21. THU AND FRI
MAX TEMPS SHOULD WARM SLIGHTLY...WITH LOWER 70S IN VALLEYS AND 60S
ACROSS HIGHER ELEVATIONS. MIN TEMPS FOR THU NT/FRI AM SHOULD FALL
INTO THE 40S FOR MOST AREAS.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST LATER TONIGHT AND
SATURDAY MORNING...PRECEDED AND ACCOMPANIED BY SOME SHOWERS.
GENERALLY VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS
ENDING 00Z/SUN...DESPITE SOME MID LEVEL CLOUDS AND SHOWERS
TONIGHT. DEPENDING ON IF MEASURABLE RAIN ACTUALLY FALLS...THERE
COULD BE ENOUGH MOISTENING OF THE BOUNDARY LAYER BETWEEN 10Z-
14Z/SAT TO PRODUCE MVFR CIGS AND VSBYS...BUT THIS APPEARS TO BE A
RATHER LOW PROBABILITY. THE BEST CHANCE THAT THIS OCCURS WOULD BE
KGFL.
AFTER THE WARM FRONT PASSES SAT MORNING...AN ISOLATED SHOWER OR
THUNDERSTORM COULD DEVELOP LATER IN THE AFTERNOON. THE BEST CHANCE
OF THIS WOULD BE AT KPOU...BUT OVERALL AREAL COVERAGE AND
PROBABILITY IS TOO LOW TO MENTION IN TAFS AT THIS TIME.
OUTLOOK...
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY NIGHT: ISOLATED SHRA.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
TONIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED
THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY...
AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM
WEATHER SUNDAY INTO MONDAY.
WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND RH VALUES WILL BE 90
TO 100 PERCENT. WINDS WILL BECOME SOUTHWEST SATURDAY AT 10 TO 15
MPH WITH RH 50 TO 60 PERCENT. RAINFALL TONIGHT AND SATURDAY MAY
PRODUCE UP TO A QUARTER TO A THIRD OF INCH. DRY WEATHER IS
EXPECTED SUNDAY AND MONDAY.
&&
.HYDROLOGY...
THE NEXT CHANCE OF SHOWERS WILL BE TONIGHT INTO SATURDAY...WITH
RAINFALL AMOUNTS EXPECTED TO BE AROUND A QUARTER TO A THIRD OF AN
INCH. THIS WILL HAVE LITTLE IMPACT ON AREA RIVERS AND STREAMS.
ONLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED SATURDAY AFTERNOON
AND NIGHT...WITH MAINLY DRY WEATHER EXPECTED FOR SUNDAY.
ANOTHER ROUND OF RAIN IS LIKELY LATE MONDAY INTO TUESDAY WITH THE
POTENTIAL FOR ANOTHER QUARTER TO THIRD OF AN INCH.
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...IAA/GJM
NEAR TERM...IAA/KL/GJM/LFM
SHORT TERM...GJM
LONG TERM...KL
AVIATION...KL
FIRE WEATHER...GJM
HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1152 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 906 PM CDT FRI MAY 15 2015
PLENTY OF WARM AIR ADVECTING INTO THE REGION AND WIDESPREAD
MID/HIGH LEVEL CLOUDS IN ADDITION TO REMAINING LOW WILL KEEP THE
TEMPS UP OVERNIGHT FOR CENTRAL ILLINOIS. ALTHOUGH LLVL RH HAS BEEN
ENHANCED BY THE EVENINGS RAINFALL...WIDESPREAD FOG NOT LIKELY AS
THE WINDS AND TEMPS STAY UP OVERNIGHT. WILL HAVE TO WATCH FOR SOME
PATCHY VIS REDUCTIONS, BUT NOT ENOUGH CONFIDENCE TO PUT IT IN THE
ZONES JUST YET. UPDATES FOR THE BREAK IN THE PRECIP...BRINGING
BACK CHANCE POPS IN THE VERY EARLY HOURS OF THE MORNING AS MODELS
STILL SPLIT OVER HOW TO HANDLE A POTENTIAL ROUND TWO.
&&
.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
MORNING UPPER AIR AND MOISTURE CHANNEL IMAGERY SHOWS CLOSED UPPER
LOW IN ROCKIES WITH A MAIN VORT LOBE IN THE CENTRAL PLAINS,
ADVECTING 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 LOCALIZED 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 ROCKIES,
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 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1149 PM CDT FRI MAY 15 2015
ILX TERMINALS STILL ANCHORED IN THE WARM SECTOR OF SORTS
TOMORROW...MAINTAINING THE TREND OF SOUTHERLY WINDS AND SHOWERS
AND THUNDERSTORMS WITH A DIURNAL COMPONENT THROUGH TOMORROW.
MODELS INCONSISTENT WITH TIMING OF THE ONSET OF SHOWERS...BUT WITH
THE RUNS THAT HAVE IT EARLIER...THEY ARE ALSO OVERDONE WITH THE
SECONDARY SHOWERS TO THE SOUTHWEST. AS A RESULT...KEEPING TO VCSH
UNTIL ROUGHLY MIDDAY. SPREAD OF PRECIP NOT A PROGRESSION BUT MORE
SCATTERED. PULLING BACK ON THE RAIN MENTION FOR THE EVENING WITH
THE MID DECK REESTABLISHING...VERY SIMILAR TO THIS EVENING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...GEELHART
LONG TERM...GOETSCH
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
404 AM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 136 AM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY
SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST.
OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND.
HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 80...WITH LOW
TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK THESE UPSTREAM WAVES OUT THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE FAVORABLE
SHORT WAVE TRACK THIS AFTERNOON. A MODEST MID/UPPER LEVEL SPEED MAX
IS ALSO EXPECTED TO LIFT ACROSS EAST CENTRAL INDIANA/WESTERN OHIO
THIS AFTERNOON WHICH MAY ALSO TEND TO FOCUS BETTER CONVECTIVE
CHANCES. HAVE CONTINUED WITH MID TO HIGH CHANCE POPS THROUGH THE DAY
WITH HIGHEST POPS FOCUSED ACROSS SOUTHEAST THIRD OF THE AREA.
INSTABILITY MAGNITUDES SHOULD BE SOMEWHAT LESS THAN YESTERDAY AS LOW
LEVEL THERMAL RIDGE IS WEAKER...AND GENERALLY EXPECTING SURFACED
BASED CAPES ON THE ORDER OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO
IS EXPECTED TO BE ON THE MARGINAL SIDE WITH THE POSSIBLE EXCEPTION
OF FAR SOUTHEAST AREAS WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY
PROMOTE DEEP LAYER SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE.
THIS MAY HELP TO CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH
OF THE NEXT SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE
WEATHER IS NOT EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS
AROUND 80 FOR TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS
ABLE TO BECOME ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE
A BIT TOO WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 136 AM EDT SAT MAY 16 2015
UPPER LEVEL RIDGING WILL REBUILD ACROSS THE GREAT LAKES REGION
TODAY...ALTHOUGH SEVERAL SMALL SCALE DISTURBANCES IN SOUTHWEST
FLOW ALOFT COMBINED WITH WEAK TO MODERATE AFTERNOON INSTABILITY
MAY RESULT IN ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS. GIVEN
WEAK NATURE TO FORCING MECHANISMS AND INSTABILITY POSSIBLY A BIT
MORE TEMPERED IN COMPARISON TO YESTERDAY...HAVE OPTED TO CONTINUE
TO REFRAIN FROM ANY MENTION WITH THE 06Z TAFS DUE TO LOW
CONFIDENCE. THUNDER CHANCES TONIGHT APPEAR TO BE QUITE LOW GIVEN
WEAKENING INSTABILITY AND BETTER FORCING HOLDING OFF UNTIL AFTER
THIS FORECAST VALID PERIOD. SOME PATCHY FOG MAY FORM OVER THE NEXT
SEVERAL HOURS AND HAVE MAINTAINED TREND TO MVFR CONDITIONS IN THE
09Z-13Z TIMEFRAME. OTHERWISE...LIGHT SOUTH WINDS OVERNIGHT WILL
BECOME SOUTHWESTERLY AFTER 14Z WITH SOME GUSTS TO 15 TO 20 KNOTS
NOT OUT OF THE QUESTION. SOME MORE PATCHY FOG IS POSSIBLE AGAIN
FOR SATURDAY NIGHT...AND WILL ADDRESS THIS MORE FULLY WITH THE 12Z
TAFS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1127 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...16/06Z
ISSUED AT 1127 PM CDT FRI MAY 15 2015
A FEW SHRA/TSRA ARE POSSIBLE OVERNIGHT...BUT COVERAGE TOO LOW FOR
INCLUSION IN THE TAFS. OTHERWISE...PRIMARY FORECAST CHALLENGE IS
THE POTENTIAL FOR FOG/STRATUS DEVELOPMENT OVERNIGHT. WITH DEWPTS
IN THE LOWER 60S AND LOW DEPRESSIONS THERE IS CLEARLY A RISK FOR
SUCH REDEVELOPMENT...HOWEVER...SATELLITE IMAGERY SHOWS PRETTY
SUBSTANTIAL MID/HIGH LEVEL CLOUDS OVERHEAD AND UPSTREAM...AND THE
SURFACE FLOW IS LIGHT BUT ORGANIZED OUT OF THE SOUTHEAST
MITIGATING THIS THREAT SOMEWHAT. ALSO NOTE THAT IT IS ALMOST
MIDNIGHT ALREADY AND ONLY ONE STATION IN IOWA IS REPORTING LOWER
THAN VFR CONDITIONS WITH ALL VSBYS UNRESTRICTED. HAVE THUS OPTED
TO GO WITH MVFR BR/CIGS OVERNIGHT BUT WILL BE CLOSELY MONITORING
OBSERVATIONAL TRENDS IN CASE AMENDMENTS BECOME NECESSARY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CURTIS
LONG TERM...DONAVON
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
400 AM CDT Sat May 16 2015
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CDT SAT MAY 16 2015
A broad upper level low was located across NV, UT and AZ early this
morning. A 65KT mid level jet max was lifting northeast across
eastern NM into western KS. The strong ascent ahead of this jet max
has helped to develop a line of showers and thunderstorms from
central NE, south-southwest into west TX. Most numerical models show
this line weakening as it moves east into a more stable airmass
across eastern KS through the morning hours.
A stronger H5 trough located along the southern base of the upper
level low will lift northeast across eastern NM into the northern TX
PNHDL through the late morning hours. Several numerical models all
show an area of scattered to numerous thunderstorms developing ahead
of a surface dryline across the eastern TX PNHDL through the mid
and late morning hours. These storms lift northeast and intensify
through the early and mid afternoon hours, as they move northeast
across western OK into south central KS. The 5Z HRRR shows this area
of thunderstorms moving northeast into the western counties of the
CWA by 20Z. Most numerical models show the atmosphere destabilizing
early this afternoon across the CWA, after the weaker storms from
this morning dissipate or lift off to the northeast. the WRF runs,
NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks
fairly weak with most models forecasting less than 100m2/s2 of 0-1KM
SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS
during the afternoon. Therefore, the environment will be favorable
for severe thunderstorms this afternoon. Another question will be
the mode of convection. If a complex of storms develops across
northwest OK late this morning and maintains itself northeast
across the CWA than any tornado threat will be quite low. Though
stronger updrafts within a QLCS or complex of thunderstorms would
produce large hail and damaging wind gusts. The HRRR and NAM 4KM
simulated reflectivity forecast more scattered to isolated
thunderstorms developing across north central OK and south central
KS early this afternoon, and moving northeast into the southwest
and southern counties of the CWA after 22Z. I suppose if we see
discrete supercells than there will be a chance for tornadoes
along with the large hail and damaging wind gusts.
Late this afternoon most models show thunderstorms developing along
the Pacific front/dryline across west central KS and western OK. The
environment will really improve ahead of the dryline late this
afternoon, with much stronger low-level vertical wind shear. Any
discrete supercells that develop along the Pacific front/dryline
across west central KS and western OK will have a chance to produce
tornadoes. Through the evening hours these discrete to scattered
supercell thunderstorms may congeal into line segments or a QLCS and
move northeast into the western counties of the CWA during the mid
evening hours. If discrete supercells move into the western counties
this evening, then there will be a chance for tornadoes. I suppose
if a QLCS develops there is a potential for meso-vortices tornadoes.
Cloud cover will probably keep high temperatures in the mid to
upper 70s.
Tonight, The upper low and lead H5 trough will lift northeast into
southwest NE. Line segments of thunderstorms or a QLCS will move
east across the remainder of the CWA during the late evening hours
into the early morning hours of Sunday. The primary hazard will be
large hail, damaging winds and heavy rainfall.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CDT SAT MAY 16 2015
On Sunday the dry slot will work across the area with lower
dewpoints but daytime highs should still reach to around 80 given
mixing and expected sun. The cold front will finally move across
the area Sunday night and it should pass through dry however there
are some signals that precip may develop along it toward Mon
morning southeast of the area. For now will keep conds dry and
with CAA on Monday expect much cooler highs and lower humidities
as dewpoints fall into the 40s. Tues should also remain dry for
most of the day with rain expected to overspread the area Tues
night and last through Weds. Limited CAPE suggests only isolated
thunder but look for another widespread soaking rain out of this
system.
Perhaps a brief dry spell on Thursday before the next upper wave
approaches for late next week into next weekend. This system looks
very similar to this weekends so an active pattern will continue.
&&
.AVIATION...(For the 06Z TAFs through 06Z Saturday Night)
Issued at 1148 PM CDT FRI MAY 15 2015
VFR prevails initially with increased low level moisture bringing
in a MVFR stratus deck with haze closer to 10Z according to short
term guidance. Line of TSRA in central KS is forecast to weaken
west of terminals and will need to monitor trends. Scattered TSRA
are possible after 15Z at KTOP/KFOE where VCTS mention is placed.
Believe the better forcing arrives late afternoon/early evening
where storms develop in central KS and track east through the
evening. Confidence in timing or duration is too uncertain to
mention at this time. Gusty south winds prevail throughout period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1202 AM CDT SAT MAY 16 2015
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 1102 PM CDT FRI MAY 15 2015
WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE A BROAD UPPER LEVEL
TROUGH OF LOW PRESSURE PUSHING SLOWLY EAST ACROSS THE GREAT BASIN
REGION. MEANWHILE, AN H5 VORT MAXIMA IS CYCLING EASTWARD ACROSS
THE DESERT SOUTHWEST WITHIN THE BROADER SCALE TROUGH. NEAR THE
SURFACE, AN AREA OF LOW PRESSURE IS POSITIONED ACROSS NORTHEASTERN
COLORADO WITH AN ATTENDANT TROUGH AXIS EXTENDING SOUTHWARD ALONG
THE KANSAS AND COLORADO BORDER.
&&
.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 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1200 AM CDT SAT MAY 16 2015
SHOWERS AND ISOLATED THUNDERSTORMS WILL SPREAD NORTHEAST ACROSS
SOUTHWEST AND CENTRAL KANSAS OVERNIGHT POTENTIALLY AFFECTING ALL TAF
SITES. OTHERWISE, VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES
THROUGH EARLY SATURDAY AFTERNOON. SCATTERED THUNDERSTORMS WILL BE
POSSIBLE AGAIN LATE SATURDAY AFTERNOON, GENERALLY IN THE VICINITY
OF KGCK AND TO THE EAST. A SURFACE LOW WILL REMAIN ANCHORED ACROSS
NORTHEASTERN COLORADO OVERNIGHT WITH AN ATTENDANT TROUGH AXIS
EXTENDING SOUTHWARD NEAR AND ALONG THE COLORADO BORDER. THIS WILL
RESULT IN SOUTHERLY WINDS OF 10 TO 20KT PERSISTING ACROSS WESTERN
KANSAS THROUGH LATE SATURDAY MORNING. THE SURFACE LOW IS THEN
EXPECTED TO DEEPEN ACROSS NORTHEASTERN COLORADO SATURDAY AFTERNOON
INCREASING WINDS UP TO AROUND 25 TO 35KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 53 82 50 69 / 40 0 0 10
GCK 51 79 47 69 / 20 0 0 0
EHA 49 79 47 69 / 10 0 0 0
LBL 51 81 50 71 / 20 0 0 0
HYS 54 79 50 67 / 60 0 0 0
P28 58 83 54 72 / 50 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...BURGERT
LONG TERM...BURGERT
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1103 PM CDT FRI MAY 15 2015
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 1102 PM CDT FRI MAY 15 2015
WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE A BROAD UPPER LEVEL
TROUGH OF LOW PRESSURE PUSHING SLOWLY EAST ACROSS THE GREAT BASIN
REGION. MEANWHILE, AN H5 VORT MAXIMA IS CYCLING EASTWARD ACROSS
THE DESERT SOUTHWEST WITHIN THE BROADER SCALE TROUGH. NEAR THE
SURFACE, AN AREA OF LOW PRESSURE IS POSITIONED ACROSS NORTHEASTERN
COLORADO WITH AN ATTENDANT TROUGH AXIS EXTENDING SOUTHWARD ALONG
THE KANSAS AND COLORADO BORDER.
&&
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 732 PM CDT FRI MAY 15 2015
SOME OF THE CONVECTIVE ALLOWING MODELS INCLUDING THE RAPID REFRESH,
THE 12KM NAM AS WELL AS THE HRRR SEEM TO BE OVERDOING CONVECTIVE
DEVELOPMENT IN THE AREA LATE THIS AFTERNOON/EARLY EVEING. THE
BETTER OPPORTUNITY WILL EVOLVE AS THE JET DYNAMICS BECOME A FACTOR
FOR ASCENT, PROBABLY AFTER MIDNIGHT FOR GCK/HYS/DDC. A WINDOW OF
CONVECTION WILL BE INCLUDED OVERNIGHT AS WELL AS A PROBABILITY
AFTER 18 Z WHEN SEVERE STORMS ARE EXPECTED SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 58 78 53 82 / 50 50 40 0
GCK 57 78 51 79 / 40 40 20 0
EHA 54 75 49 79 / 40 20 10 0
LBL 58 80 51 81 / 50 30 20 0
HYS 61 77 54 79 / 50 60 60 0
P28 62 78 58 83 / 40 50 50 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...BURGERT
LONG TERM...BURGERT
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1145 PM CDT FRI MAY 15 2015
.MESOSCALE UPDATE...
AREAL FLOOD ADVISORIES WILL BE ALLOWED TO EXPIRE AS
ISSUED...MIDNIGHT FOR SOUTH SHORE POLYGON AND 115 AM FOR NORTH
SHORE POLYGON. CONVERGENT BOUNDARY SHOULD WEAKEN WHILE OUTFLOW
BECOMES A MORE DOMINANT PLAYER OVERNIGHT FOR PROPAGATION OF STORM
INTO THE MISSISSIPPI COASTAL COUNTIES OVERNIGHT. HRRR MODEL RUN
FAVORS THIS SOLUTION AND MAY WARRANT ADDITIONAL ISSUANCES OF FLOOD
ADVISORIES...POSSIBLE FLASH FLOOD WARNINGS SHOULD A CONVERGENCE
AXIS BECOME ESTABLISHED FOR ANY SIGNIFICANT DURATION TONIGHT AND
EARLY SATURDAY MORNING. 24/RR
.AVIATION...
ONLY TERMINALS CURRENTLY WITH CONVECTIVE IMPACTS ARE KMSY AND KASD
AND EXPECTING DIMINISHING COVERAGE NEXT 1-2 HOURS.
MEANWHILE...KGPT AND KPQL HAVE HAD MINIMAL INFLUENCES FROM AREAL
CONVECTION TODAY AND MAY BE PRONE TO NOCTURNAL DEVELOPMENTS
BETWEEN 06-11Z. MVFR CONDITIONS AT MOST LOCATIONS TONIGHT
IMPROVING TO LOW END VFR CIGS OUTSIDE CONVECTION SATURDAY. GUST
POTENTIAL SOULD BE AROUND 30 KT WITH THE INITIAL STRONGER STORMS
BETWEEN 16Z-18Z CAPABLE OF WET MICROBURST GUSTS 40-45 KT...AND
FAVORED IN WESTERN TAFS LIKE KBTR AND KMCB WHERE MOISTURE RECOVERY
WILL BE GREATEST. 24/RR
&&
.PREV DISCUSSION... /ISSUED 840 PM CDT FRI MAY 15 2015/
..SOUNDING DISCUSSION...
ATMOSPHERE IS JUICY TONIGHT WITH A PRECIPITABLE WATER /PW/ VALUE
OVER 2 STANDARD DEVIATIONS ABOVE NORMAL AT 2.14 INCHES. THIS
DESTROYS THE OLD RECORD PW VALUE FOR THIS DATE AND TIME OF 1.8
INCHES AS FOUND ON THE SPC PW CLIMATOLOGY PAGE. THE TROPICAL
MOISTURE IS BEING DRAWN INTO THE AREA ON SOUTHERLY WINDS AVERAGING
20 TO 25 KNOTS IN THE LOW AND MID-LEVELS. A PEAK WIND SPEED OF 52
KNOTS WAS FOUND AT 46200 FEET. THERE IS A FAIR AMOUNT OF
INSTABILITY IN THE ATMOSPHERE...WHICH MAY ALLOW SHOWERS AND
THUNDERSTORMS TO LAST UNTIL AROUND OR PERHAPS AN HOUR OR TWO AFTER
MIDNIGHT.
00Z BALLOON INFO: LAUNCH WAS DELAYED A BIT DUE TO LIGHTNING IN THE
AREA...BUT OTHERWISE A ROUTINE FLIGHT. THE BALLOON ASCENDED FOR 74
MINUTES WHILE TRAVELING 13 MILES DOWNRANGE BURSTING EAST OF
NICHOLSON AT A HEIGHT OF 15.1 MILES ABOVE THE GROUND.
ANSORGE
PREV DISCUSSION... /ISSUED 354 PM CDT FRI MAY 15 2015/
PREVIOUS LONG TERM...LITTLE CHANGE IN THE LONG TERM FORECAST
PATTERN WITH CHANCES OF SHOWERS AND THUNDERSTORMS EACH DAY THROUGH
THE WORK WEEK. BLENDED GUIDANCE WILL BE USED WITH MAINLY
CHANCE/SCATTERED RAINFALL CHANCES DURING THE DIURNALLY FAVORED TIME
PERIODS. ALSO LITTLE DAY TO DAY TEMPERATURE CHANGE WITH THE
EXCEPTION OF THOSE SITES SEEING CONVECTION EARLY IN THE DAY.
35
AVIATION... SHOWERS AND THUNDERSTORMS WILL GENERALLY BE A POTENTIAL
IMPACT TO TERMINALS THROUGH THE NEXT FEW HOURS BEFORE STARTING TO
WIND DOWN AFTER AROUND 02Z. SO WILL CARRY -RA AND TEMPO TSRA IN MOST
TAFS THRU THIS AFTN. OVERNIGHT CONDITIONS WILL RANGE FROM MVFR TO
IFR CEILINGS.
MEFFER
MARINE... HIGH PRESSURE OVER THE EAST COAST WILL MAINTAIN A
SOUTHEASTERLY FLOW THROUGH MONDAY. THE PRESSURE GRADIENT WILL KEEP
OFFSHORE WATERS RIGHT AT THE THRESHOLD FOR EXERCISE CAUTION. IT DOES
APPEAR IT WILL BE EXCEEDED TONIGHT...SO GOING IT HAVE THE SCS
HEADLINE IN GRIDS THEN. THE HIGH WILL MOVE INTO THE GULF EARLY NEXT
WEEK CAUSING WIND SPEEDS TO LOWER EVEN MORE WITH A LIGHT BREEZE OUT
OF THE WEST BY WED. EACH DAY WILL BRING A GOOD CHANCE OF SH/TS
THROUGH THE MIDDLE OF NEXT WEEK.
MEFFER
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 70 83 71 85 / 50 60 50 50
BTR 71 85 72 86 / 40 60 50 50
ASD 72 83 73 85 / 50 60 50 50
MSY 73 84 75 85 / 40 60 50 50
GPT 74 82 75 84 / 50 60 40 40
PQL 72 82 73 84 / 50 60 50 50
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1132 PM CDT FRI MAY 15 2015
.AVIATION...LOW LEVEL WIND FIELD WILL BE STRENGTHENING OVERNIGHT
ACROSS THE AREA BRINGING IN WIDESPREAD MVFR CLOUDINESS. ENHANCED
LIFT AHEAD OF AN APPROACHING MID/UPPER TROF WILL MAINTAIN A FEW
SHOWERS OVER ACADIANA. MAINTAINING VCSH THROUGH THE NIGHT AT ARA
AND LFT. PASSAGE OF AFOREMENTIONED TROF AND DRIER AIR IN ITS WAKE
WILL RESULT IN LESS CONVECTION SATURDAY THAN TODAY FOR THE AREA.
WILL KEEP VCSH FOR THE MORNING AT ALL TERMINALS AND VCTS THROUGH
THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 1017 PM CDT FRI MAY 15 2015/
DISCUSSION...
LIFT ASSOCIATED WITH A SHORTWAVE TROF LIFTING THROUGH EASTERN TX
ALONG WITH A DEEP MSTR POOL PER KLIX 00Z RAOB HELPING TO
SUSTAIN/GENERATE CONVECTION ACROSS SOUTH CENTRAL/SOUTHEAST LA AND
THE ADJACENT COASTAL WATERS. POP/WX/QPF GRIDS WERE ADJUSTED IN THE
SHORT TERM BASED PRIMARILY ON THE HRRR AND RADAR TRENDS...WITH A
NOD TO THE FORMER OVERNIGHT WHICH SHOWS ISOLATED TO PERHAPS
SCATTERED ACTIVITY CONTINUING EAST OF THE SABINE RIVER. MINOR
TWEAKS TO REMAINING GRIDS...WITH A SLIGHT INCREASE IN WIND/WIND
GUST GRIDS REQUIRING A SCEC HEADLINE OVER THE GULF WATERS.
13
PREV DISCUSSION... /ISSUED 650 PM CDT FRI MAY 15 2015/
AVIATION...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE OVER
CENTRAL LOUISIANA INTO ACADIANA. REMAINDER OF THE AREA IS CLEAR OF
ANY PRECIP. MUCH OF THIS ACTIVITY WILL BE DYING OFF IN THE NEXT
FEW HOURS WITH COOLING. WILL HOWEVER MAINTAIN VCSH THROUGH THE
NIGHT AT LFT AND ARA WITH ACTIVITY NOTED OFFSHORE FROM THESE
SITES. OTHERWISE...VFR ONGOING OVER THE AREA AT THIS TIME.
EXPECTING ANOTHER ROUND OF MVFR STRATOCU TO DEVELOP AS THE NIGHT
PROGRESSES. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO RETURN
AREA-WIDE SATURDAY MORNING...TRANSITIONING TO TSRA FOR THE
AFTERNOON.
PREV DISCUSSION... /ISSUED 325 PM CDT FRI MAY 15 2015/
DISCUSSION...AN UPPER TROUGH REMAINS ACROSS THE WEST HALF OF THE
COUNTRY THIS AFTERNOON WITH MULTIPLE SHORT WAVES ROTATING AROUND THE
LARGER GYRE. ONE SHORT WAVE IS PUSHING THROUGH THE EAST HALF OF TX
WITH A LINE OF STORMS PUSH ACROSS THE CENTRAL TX COAST. FARTHER
EAST ACROSS DEEP SE TX AND LA WHERE THE HEATING OF THE DAY HAS
COMBINED WITH THE UPPER DIVERGENCE IN PLACE TO DEVELOP SCT TO
NUMEROUS SHOWERS AND STORMS AWAY FROM THE COAST. AS SUNSET
APPROACHES CONVECTION IS EXPECTED TO DECREASE INCLUDING THE
CENTRAL TX COAST QLCS, HOWEVER AREAS OF RAIN MAY MOVE INTO THE
WEST HALF OF THE CWA AS THE REMNANTS OF THE LINE OF STORMS DRAWS
CLOSER AND ADDITIONAL SCT STORMS MAY REDEVELOP LATER IN THE NIGHT
AS THE SHORT WAVE MOVES IN. A SIMILAR SITUATION IS EXPECTED FOR
SAT AND SUN AS CONVECTION WILL REDEVELOP EACH AFTERNOON AND
GRADUALLY DECREASE THROUGH THE LATE AFTERNOON AND EARLY EVENING.
A SLIGHT INCREASE IN COVERAGE IS EXPECTED MONDAY AND TUESDAY AS THE
LARGER WESTERN TROUGH AXIS MOVES ACROSS THE REGION.
FROM MID WEEK ON MORE TYPICAL EARLY SUMMER WEATHER IS EXPECTED
WITH ISOLATED TO WIDELY SCT AFTERNOON STORMS OCCUR UNDER WEAK
RIDGING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 70 85 72 87 / 20 60 30 50
LCH 74 85 75 86 / 30 40 20 40
LFT 72 86 74 87 / 40 50 30 40
BPT 75 86 75 86 / 20 30 20 40
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL 6 AM CDT SATURDAY FOR GMZ450-
452-455-470-472-475.
&&
$$
AVIATION...23
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN
ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER
OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID
SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF
CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK
MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH
VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT
RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU
MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE
SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH
PLAINS OF S DAKOTA TO NEB.
BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER
MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER
LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY
CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH
TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF
SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR
EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT
RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND
NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA
OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY.
MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF
AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY
OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR
TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF
CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT
LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER
100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR
MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH
EDGE OF H85-H7 MOISTURE TRANSPORT.
EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT
WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE
ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE
CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS
WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS
NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS
NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF
FOG...LOCALLY DENSE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 520 AM EDT SAT MAY 16 2015
SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM
THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE
SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50
KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5
INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL
ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF
INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS
INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400-
800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z
MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE
COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE
ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND
THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S
WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY 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 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO
SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY
BE DRY OVERNIGHT.
MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW
ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON
BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT
COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS
ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY
END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC
FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD
-SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER
TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH
EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO
GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W-
NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST.
MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO
VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS
BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY
LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR
CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN.
DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES
FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON
ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE
LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR
SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND
PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE
VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY
FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED
THRU FRI...BUT REMAIN BLO NORMAL. &&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 142 AM EDT SAT MAY 16 2015
LIGHT WINDS AND ANTECEDENT MOISTURE CONTINUE TO MAKE THE FORECAST A
CHALLENGE THIS MORNING. THERE CONTINUES TO BE A POTENTIAL FOR LOW CIGS
AND FOG AT ALL THREE SITES. HOWEVER ONLY KSAW AT IFR CIGS AT THIS
TIME WHILE KCMX AND KIWD ARE MVFR. CONCERN IS 0Z NAM BUFKIT SUPPORTS
LOW CLOUDS/FOG AT ALL THREE SITES...HOWEVER THE NAM HAS BEEN NOTED AS
BEING A BIT AGGRESSIVE WITH LOW LEVEL MOISTURE. AT THIS TIME...STILL
EXPECT IFR CONDITIONS AT KCMX AND KSAW FOR A TIME OVERNIGHT BUT DO
NOT EXPECT RESTRICTIONS TO BE AS SIGNIFICANT AS SUGGESTED BY THE NAM.
FORTUNATELY...LOW CLOUDS AND FOG WILL LIFT AFTER SUNRISE WITH VFR
CONDITIONS PREVAILING BY 15Z AT THE LATEST AT KCMX AND KSAW. THERE IS
A SLIGHT CHANCE OF SHOWERS AND PERHAPS A THUNDERSTORMS MOVING INTO
THE KIWD AREA CLOSE TO THE END OF THE FORECAST BUT FOR NOW HAVE LEFT
THIS OUT OF THE CURRENT DUE TO A HIGH DEGREE OF UNCERTAINTY WITH THE
TIMING OF THE ARRIVAL OF THE CONVECTION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW
PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING
E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF
THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY
MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE
LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL
USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND
TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE
EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION
WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20
KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250.
&&
$$
SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...RJT
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
406 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT SAT MAY 16 2015
VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST
THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT
CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION
THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE
ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE
CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS
NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE
MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME
SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH
THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT
MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS
SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE
RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE
AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL
LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD
OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE
ACROSS THE PLAINS AND INTO THE UPPER MIDWEST.
SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE
AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING
UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC
HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE
MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO
MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO
MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND
SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER
MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 406 AM CDT SAT MAY 16 2015
THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A
SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF
MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE
TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE
FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID
ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON.
THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW
PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS
MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE
AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER
LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE
COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM
WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES
APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON
SUNDAY AFTERNOON.
THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY
REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE
LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL
MN/WI THROUGH MONDAY.
BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS
AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL
CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO
ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH
FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE
60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY
NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS
PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1105 PM CDT FRI MAY 15 2015
SOME LOW CLOUDS REMAIN ACROSS SOUTHERN MN AND WESTERN WI AS A
WARM FRONT CONTINUES TO MOVE NORTH THROUGH IOWA. AREAS OF MVFR
CIGS ARE POSSIBLE OVERNIGHT THROUGH SATURDAY MORNING...ESPECIALLY
FROM 12Z-15Z SATURDAY AS THE FRONT MOVES INTO SOUTHERN MN.
SCATTERED SHOWERS AND THUNDERSTORMS SHOULD DEVELOP OVER WESTERN MN
SATURDAY MORNING...AND SPREAD INTO CENTRAL AND EASTERN MN BETWEEN
18Z-00Z. BRIEF PERIODS OF IFR CONDITIONS ARE POSSIBLE IN ANY
STORMS THAT DEVELOP...AS WELL AS GUSTY WINDS AND A CHANCE OF HAIL
IN THE STRONGEST STORMS...ESPECIALLY AT AXN AND RWF DURING
SATURDAY AFTERNOON AND EVENING.
KMSP...SCATTERED/BROKEN AREAS OF LOW CLOUDS WILL CONTINUE
OVERNIGHT...AND MVFR CIGS ARE POSSIBLE BETWEEN 12Z-15Z AHEAD OF A
WARM FRONT MOVING THROUGH SOUTHERN MN. CIGS SHOULD REBOUND LATER
SATURDAY MORNING...BUT THUNDERSTORM CHANCES WILL INCREASE DURING
THE AFTERNOON. PERIODS OF IFR CONDITIONS ARE POSSIBLE IN THE
THUNDERSTORMS...AND WILL BECOME MORE LIKELY AFTER 00Z AS STORM
CHANCES INCREASE.
/OUTLOOK FOR KMSP/
SUN...VFR WITH SCATTERED IFR/TSRA. WINDS S AT 15-25 KTS.
MON...VFR. WINDS NW AT 15-25 KTS.
TUE...VFR. WINDS N AT 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...LS
AVIATION...ADL
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1201 AM CDT Sat May 16 2015
.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 06Z TAFS through 06Z Saturday Night)
Issued at 1148 PM CDT FRI MAY 15 2015
An area of showers and perhaps a few thunderstorms will spread
north into portions of southern Missouri late tonight and early
Saturday morning. MVFR ceilings will also accompany this
activity...especially around Branson. There is even some potential
for IFR ceilings across south-central Missouri. Confidence in this
scenario remains low enough to preclude IFR from the TAFs.
Additional scattered thunderstorm development is then expected
from late Saturday morning into early Saturday afternoon across
western Missouri. MVFR and brief IFR conditions can be expected
with any thunderstorms. Outside of thunderstorms, surface winds
will increase out of the south on Saturday and will become gusty.
Yet another round of thunderstorms will then be possible across
western Missouri late Saturday evening towards the end of the TAF
period.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Schaumann
AREA FORECAST DISCUSSION
NWS BISMARCK ND
455 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUDCOVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE
WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY
THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG
NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE
ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN WILL LIFT
NORTH BRINGING A CHANCE OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS
TO THE TERMINALS THIS MORNING. CEILINGS WILL LOWER AS THE RAIN
MOVES INTO THE REGION.
THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH
TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE
SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN
SATURDAY AFTERNOON AND NIGHT. CHANCES ARE BETTER SATURDAY AFTERNOON
AND EVENING FOR THUNDER.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE 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.
&&
$$
SHORT TERM...JV
LONG TERM...JPM
AVIATION...JV
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
115 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 114 AM CDT SAT MAY 16 2015
MAIN UPDATE TO THE FORECAST WAS TO SLOW THE ONSET OF PRECIPITATION
IN THE SOUTHWEST. THOUGH IT IS RAINING IN HETTINGER...THE LEADING
EDGE OF RAIN SHOWERS HAD NOT YET REACHED DICKINSON OR GRANT OR SIOUX
COUNTY. THE LATEST HRRR MODEL WAS HANDLING THE CURRENT PRECIPITATION
AREA WELL...SO BACKED OFF ON PRECIP CHANCES NORTH AND EAST FOR EARLY
THIS MORNING AND INCREASED CHANCES AFTER AROUND 3 AM CDT. OTHERWISE
FORECAST ON TRACK FOR THE OVERNIGHT HOURS.
UPDATE ISSUED AT 946 PM CDT FRI MAY 15 2015
MAIN UPDATE TO THE FORECAST THIS EVENING WAS TO SPREAD THE
POSSIBILITY OF ISOLATED THUNDERSTORMS INTO THE WESTERN PART OF THE
STATE. FORECAST MUCAPE FROM THE RAP SHOWS WEAK INSTABILITY FROM
WESTERN INTO SOUTH CENTRAL NORTH DAKOTA OVERNIGHT. CURRENT RADAR
MOSAIC INDICATES SHOWERS AND THUNDERSTORMS IN WESTERN SOUTH DAKOTA
CONTINUE TO MOVE NORTH...WHICH IS WELL COVERED IN THE FORECAST
WITH HIGH POPS IN PLACE OVERNIGHT. DECIDED TO ISSUE THE SPECIAL
WEATHER STATEMENT (SPS) AGAIN TO HIGHLIGHT THE ACTIVE WEATHER IN
THE FORECAST FOR THIS WEEKEND.
UPDATE ISSUED AT 645 PM CDT FRI MAY 15 2015
REGIONAL RADAR MOSAIC SHOWERS A FEW LIGHT SHOWERS MOVING ACROSS
WESTERN NORTH DAKOTA INTO EASTERN MONTANA. FARTHER
SOUTH...THUNDERSTORMS WERE LIFTING NORTH ACROSS PARTS OF WESTERN
SOUTH DAKOTA. THE LATEST HRRR AND RAP SUGGEST IT WILL TAKE A
FEW MORE HOURS BEFORE THE MAIN AREA OF RAIN IN SOUTH DAKOTA
REACHES THE SOUTHWEST PART OF THE STATE. THE HRRR ALSO SUGGESTS
THERE COULD BE A FEW ISOLATED SHOWERS IN ADVANCE OF THE MAIN AREA
OF RAIN...SO DID NOT REMOVE POPS ALTOGETHER IN THE NEAR TERM...BUT
DID DECREASE THEM TO SOME DEGREE EARLY THIS EVENING. MADE MINOR
ADJUSTMENTS TO SKY COVER AND TEMPERATURES...BUT OVERALL THE
REMAINDER OF THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
MAIN ISSUES IN THE SHORT TERM ARE TIMING THE START OF
PRECIPITATION THIS EVENING AND POSSIBLE SEVERE THUNDERSTORMS
SATURDAY. MODELS AND RADAR SHOWING SLOWER TRENDS OF PRECIPITATION SO
WILL DELAY THE ONSET OF PRECIP ACROSS THE SOUTH CENTRAL AND JAMES
RIVER VALLEY TO MID TO LATE EVENING. NAM/GFS BOTH HAVE A FAIRLY
GOOD CAP LOWER LEVELS. THERE IS SOME ELEVATED CAPE THIS EVENING AND
OVERNIGHT SO REFINED THE THREAT OF NON SEVERE THUNDERSTORMS
TONIGHT TO JUST THE SOUTH CENTRAL AND AFTER 9 PM CDT. ON SATURDAY
LOOKING FRO A MORE SIGNIFICANT SHORTWAVE TROUGH SUPPORTING
THUNDERSTORMS. BEST CAPE REMAINS SOUTH CENTRAL WITH THE JAMES
RIVER VALLEY MORE CAPPED TRENDING TO TALL SKINNY CAPE BY EVENING.
THIS WOULD LEND LESS SUPPORT TO SEVERE MORE TO MODERATE RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
VERY ACTIVE WEATHER WILL OCCUR OVER THE WEEKEND WITH NUMEROUS
IMPACTS AS A STRONG STORM SYSTEM CROSSES THE NORTHERN PLAINS.
INITIALLY...SEVERE THUNDERSTORMS WILL BE THE THREAT SATURDAY
EVENING...THOUGH SURFACE BASED INSTABILITY WILL DIMINISH WHILE
PROFILES SATURATE PER FORECAST SOUNDINGS. MEANWHILE A STRONG 100KT
JET WILL BEGIN NOSING INTO THE DAKOTAS AND HELP DEEPEN THE CUT OFF
UPPER LOW WHICH IS LOCATED OVER SOUTH DAKOTA AT 12Z SUNDAY.
DEEP SURFACE LOW REACHES SOUTHEASTERN NORTH DAKOTA BY 00Z MON WITH
STRONG SURFACE PRESSURE GRADIENT ACROSS THE STATE...26MB CHANGE FROM
NORTHWEST ND TO THE SOUTHEAST PART OF THE STATE PER GFS. SUB-
FREEZING 850MB TEMPS DROP SOUTHWARD INTO CENTRAL NORTH DAKOTA...WITH
SOUNDINGS SUPPORTING A CHANGEOVER OF RAIN TO SNOW LATE SUNDAY/SUNDAY
NIGHT. WPC WINTER WEATHER DESK SHOWS AMOUNTS AROUND 2-4 INCHES
ACROSS THE NORTH. TRAVEL COULD BECOME HAZARDOUS IN SOME AREAS WITH
COMBINATION OF STRONG WIND AND SNOW. BY MID-DAY MONDAY THE LOW
CENTER REACHES THE GREAT LAKES WITH HIGH PRESSURE BUILDING ACROSS
THE STATE. MAX TEMPS WILL GRADUALLY MODERATE TO THE 50S AND 60S BY
WED/THU.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 114 AM CDT SAT MAY 16 2015
THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE
ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN ACROSS SOUTH
DAKOTA WILL LIFT NORTH BRINGING A CHANCE OF SHOWERS AND PERHAPS A
FEW THUNDERSTORMS TO THE TERMINALS THIS MORNING. CEILINGS WILL LOWER
AS THE RAIN MOVES INTO THE REGION.
THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH
TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE
SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN
SATURDAY AFTERNOON AND NIGHT. CHANCES ARE BETTER SATURDAY AFTERNOON
AND EVENING FOR THUNDER.
&&
.HYDROLOGY...
ISSUED AT 303 PM CDT FRI MAY 15 2015
ENSEMBLE SITUATIONAL AWARENESS TABLE SHOWS PRECIPITABLE WATER
OVER OUR AREA AROUND 90TH PERCENTILE FROM SATURDAY INTO SUNDAY
AFTERNOON. FORECAST PRECIP AMOUNTS THROUGH 00Z MONDAY RANGE FROM
AROUND 0.75 INCHES OVER SOUTHWESTERN ND TO 2+ INCHES...MAINLY
NORTH AND EAST. CONTEMPLATED AN AREAL FLOOD WATCH...BUT THE
HEAVIEST QPF AMOUNTS WITH THIS STORM ARE GENERALLY NORTH AND EAST
OF THE AREAS THAT HAVE RECEIVED THE HEAVIEST PRECIPITATION OVER
THE PAST COUPLE WEEKS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...JNS
AVIATION...JV
HYDROLOGY...WAA/JNS
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
441 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 435 AM CDT SAT MAY 16 2015
TWO WAVES OF SHOWERS AND THUNDERSTORMS ARE EXPECTED TO AFFECT ALL
TERMINALS TONIGHT AND AGAIN SATURDAY AFTERNOON. A STRONG WARM
FRONT/LLJ SURGING NORTH ALONG WITH AN UPPER LEVEL TROUGH/JET STREAK
WILL CONTINUE TO SPREAD THE FIRST ROUND OF SHOWERS AND THUNDERSTORMS
ACROSS ALL OF THE AREA INTO SATURDAY MORNING. EXPECT MAINLY MVFR
CEILINGS AND VISIBILITIES TONIGHT. THE RAIN AND STRATUS ARE EXPECTED
TO LIFT NORTH WHILE NEW SHOWER AND THUNDERSTORM DEVELOPMENT IS
EXPECTED SATURDAY AFTERNOON. SOME OF THESE COULD BE SEVERE.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
340 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1107 PM CDT FRI MAY 15 2015
CURRENTLY...MVFR TO VFR CONTINUES TO DOMINATE THE SIOUX FALLS
FORECAST AREA. MOST OF THE MVFR IS BOTTLED UP ALONG AND NORTH OF I
90 WITH PRIMARILY VFR SOUTH OF I 90. OVERALL CONFIDENCE IS LOW
WITH THE 06Z SET OF TAFS WITH THE DETAILS. MODELS INCLUDING THE
LATEST NAM/GFS AND GEM REGIONAL CONTINUE TO SHOW A LOT OF LOW
LEVEL HUMIDITY BUILDING BACK IN BETWEEN 06Z AND 12Z TONIGHT BUT
HOW MUCH OF THIS IS BELIEVABLE REMAINS TO BE SEEN. TAKEN
LITERALLY...ALL OF THE TAF SITES WOULD GO IFR IF NOT LIFR BY 09Z
OR 10Z SATURDAY. WITH A RELATIVELY DRY EAST TO SOUTHEAST FLOW OF
AIR AM NOT BUYING THAT TOTALLY...AND OPTED TO HEDGE AND PUT IN
MVFR INSTEAD FOR NOW. THERE COULD BE ONE BAND OF RAIN MOVING
THROUGH SOUTHEAST SD AND EAST CENTRAL SD EARLY SATURDAY
MORNING...AND AGAIN ACROSS PARTS OF THE AREA LATE SATURDAY
AFTERNOON. FOR NOW...LEFT OUT THE MENTION OF THUNDERSTORMS AS
ELEVATED INSTABILITY IS ABUNDANT...BUT REMAINS TOO SKITTISH TO
MENTION AT A POINT LOCATION. AND A BULK OF THE ORGANIZED RAINFALL
WHEN THERE WILL BE THUNDERSTORMS FOR SURE DOES NOT OCCUR UNTIL IT
IS ON SIOUX CITY`S DOORSTEP TOWARD THE END OF THE TAF PERIOD. SO
AGAIN...LEFT IT OUT FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1109 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 914 PM CDT FRI MAY 15 2015
UPDATED EARLIER THIS EVENING TO REDUCE THE CHANCES FOR RAIN AND
STORMS THROUGH THE OVERNIGHT HOURS TO SLIGHT CHANCE OR NONE.
HOWEVER AM RELUNCTANT TO RADICALLY ALTER SHOWER AND THUNDERSTORM
CHANCES LATE TONIGHT AS THE HRRR AND NOW THE NEW NAM12 SHOW SOME
DEVELOPMENT ARCING THROUGH IN A NORTHWEST TO SOUTHEAST BAND. THIS
OCCURS LATE TONIGHT AND EARLY SATURDAY ALONG AN ELEVATED WARM
FRONT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 414 PM CDT FRI MAY 15 2015
DEEP UPPER TROUGHING OVER THE SOUTHWESTERN UNITED STATES CONTINUES
TO POUR MOISTURE NORTHWARD INTO THE PLAINS THIS AFTERNOON.
HOWEVER...FOCUS FOR CONVECTION HAS BEEN SPLIT THROUGH MUCH OF THE
DAY...WITH MCV LIFTING NORTHWARD THROUGH WESTERN SD AND A SECONDARY
SHORTWAVE DRIVING CONVECTION IN THE MID/LOWER MISSOURI RIVER VALLEY.
OVERHEAD...WEAK ISENTROPIC ASSENT TIED NEAR THE 305K SFC CONTINUES
TO PRODUCE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
HEADING INTO THE LATE AFTERNOON AND EVENING HOURS...MAIN FOCUS TURNS
TO WESTERN NE/SD AS UPPER JET BEGINS TO NOSE INTO THE PLAINS.
ALREADY A WELL DEVELOPED WARM FRONT STRETCHING ACROSS PORTIONS OF
NEBRASKA...BUT THE REINFORCING ELEVATED CONVECTION HAS KEPT THIS
BOUNDARY SW OF THE CWA THROUGH THE DAY. WITH 850:700 MB FLOW
BEGINNING TO BACK INTO THE WESTERN PLAINS ONGOING SHOWER ACTIVITY IN
THE LOCAL AREA MAY BEGIN TO WANE AS EVENING APPROACHES WITH
CONVECTION OVER NEBRASKA PANHANDLE TAKING OFF. WITH THE SFC WARM
FRONT TRYING TO REACH THE NE/SD LINE IN SOUTH CENTRAL SD...AN
ISOLATED STORM MAY STILL BE POSSIBLE EARLY THIS EVENING NEAR THE
MISSOURI RIVER.
THROUGH THE OVERNIGHT HOURS...LATEST HIGH RES GUIDANCE HINTS AT
SEVERAL CLUSTERS OF STORMS LIFTING NORTHEAST ACROSS NE/SD OVERNIGHT.
AS THE LEAD SHORTWAVE ENTERS THE PLAINS LATE THIS EVENING...WE MAY
BEGIN TO SEE THE LLJ VEER SOUTHWESTERLY WHICH COULD REIGNITE
ADDITIONAL ELEVATED CONVECTION FURTHER SOUTHEAST THROUGH CENTRAL
NEBRASKA AND SOUTH CENTRAL SD ALONG ELEVATED BOUNDARY LIFTING
NORTHEAST. INSTABILITY WOULD BE WANING AT THIS POINT...BUT COULD
BE DEALING WITH MARGINAL HAIL OR PERHAPS BRIEF WIND GUSTS GIVEN
PARALLEL ORIENTATION OF LOW LVL FLOW. THIS STRONGER STORM RISK WOULD
MAINLY BE WEST OF THE JAMES RIVER INTO THE EARLY MORNING
HOURS...HOWEVER THE RISK OF CONVECTION COULD SPREAD ALL THE WAY
EASTWARD INTO WESTERN MN.
FOR SATURDAY...A VERY TRICKY FORECAST REMAINS. DEEP MERIDIONAL FLOW
IS EXPECTED TO FURTHER ENHANCE MOISTURE OVERNIGHT INTO THE
AREA...WITH LLJ KEEPING ELEVATED CONVECTION LINGERING OVER THE CWA
INTO EARLY SATURDAY MORNING. A MUCH STRONGER WAVE WILL PIVOT INTO
THE PLAINS SATURDAY AFTERNOON. THE BIGGEST QUESTION FOR
SATURDAY...GIVEN THE DEEP MERIDIONAL FLOW...IS THE DEGREE OF CLOUD
COVER AND INSTABILITY THAT CAN GROW THROUGH THE AFTERNOON. THERE
ARE SOME HINTS THAT LINGERING CLOUD COVER AND ELEVATED SHOWERS MAY
WORK TO REINFORCE THE EML IN THE AFTERNOON...WITH MODELS HINTING AT
A WEAK SHORTWAVE RACING NORTHWARD AND THROUGH THE AREA BY MID-DAY
SATURDAY. HOWEVER...THE BEST CHANCE FOR ANY MORE SUBSTANTIAL GROWTH
IN SFC BASED INSTABILITY WILL BE ALONG A NORTH-SOUTH ORIENTATED
SFC BOUNDARY ACROSS WEST CENTRAL SD/NE. THAT SAID...CANNOT RULE
OUT A FEW STRONG STORM CLUSTERS...MAINLY BOWING SEGMENTS FURTHER
EAST...ESPECIALLY IF STRONGER POCKETS OF INSTABILITY CAN GROW
GIVEN THE UNIDIRECTIONAL FLOW AND DECENT SPEED SHEAR ALOFT.
AGAIN...VERY CONDITIONAL AND UNCERTAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 414 PM CDT FRI MAY 15 2015
THE CHANCE FOR THUNDERSTORMS WILL INCREASE RAPIDLY SATURDAY
EVENING AS A STRONG SHORT WAVE TROUGH AND JET STREAK MOVE
NORTHWARD INTO SOUTH DAKOTA. EXPECTED SCENARIO AT THIS TIME IS
THAT THUNDERSTORM COVERAGE WILL SLOWLY INCREASE THROUGH THE
EVENING AS WAVE APPROACHES WITH A CLUSTER OF SHOWERS AND
THUNDERSTORMS MOVING INTO THE MISSOURI VALLEY AROUND SUNSET AND
REACHING I90 BEFORE MIDNIGHT. WITH ALMOST NO CAPPING
INVERSION...THESE SHOWERS AND STORMS WILL CONTINUE DEVELOP AND MOVE
NORTHEAST THROUGH THE NIGHT. WITH WIDESPREAD STORMS...SEVERE
WEATHER IS UNLIKELY EXCEPT AHEAD OF THE MAIN CLUSTER OF STORMS IN
THE EVENING...ASSUMING ENOUGH INSTABILITY IS PRESENT TO PRODUCE A
STRONG ENOUGH UPDRAFT TO SUPPORT MARGINALLY SEVERE HAIL. AS NOTED
ABOVE...THIS THREAT IS VERY CONDITIONAL AND UNCERTAIN AS CAPES BY
EVENING WILL LIKELY BE AT OR BELOW 1000 J/KG. INSTEAD EXPECTING A
WIDESPREAD 0.5 TO 1.0 INCH OF RAIN SATURDAY NIGHT. LOCAL AMOUNTS
COULD EXCEED 1.5 INCHES IN PORTIONS OF THE AREA. WITH THE CLOUDS
AND PRECIPITATION LOWS WILL BE AROUND 60.
ON SUNDAY...SHOWERS AND STORMS WILL LINGER INTO THE
MORNING...ESPECIALLY NORTH OF I90. THEN A DRY SLOT WILL MOVE OVER
THE AREA WHICH SHOULD BRING A RESPITE TO THE PRECIPITATION TO MOST
AREA. A DRY LINE IS THEN EXPECTED TO MOVE ACROSS THE AREA ON
SUNDAY MORNING. AT THIS POINT...HAVE LOW POPS WITH THE DRY LINE
AS UPPER FORCING FOR ASCENT IS MINIMAL AND ATMOSPHERE WILL BE
FAIRLY STABLE FOLLOWING THE OVERNIGHT CONVECTION. A COLD FRONT
WILL MOVE ACROSS SUNDAY AFTERNOON. WITH LIMITED MOISTURE...
PRECIPITATION WILL NOT BE AS WIDESPREAD AND IS EXPECTED TO BE
FOCUSED CLOSER TO THE UPPER LOW MOVING ACROSS CENTRAL SD AND
EASTERN ND. SO HAVE THE HIGHEST POPS NORTH OF INTERSTATE 90. WHILE
THUNDER IS POSSIBLE WITH ANY STORMS...WITH THE LIMITED INSTABILITY
AND MOISTURE...HAVE PRIMARILY RAIN SHOWERS WITH A LOWER
PROBABILITY OF THUNDER. HIGHS WILL BE IN THE MID 70S WHERE THE
COLD FRONT WILL MOVE THROUGH IN THE LATE AFTERNOON...WITH MID 60S
IN CENTRAL SOUTH DAKOTA WHERE THERE WILL BE MORE CLOUDS AND MUCH
EARLY COLD FRONTAL PASSAGE.
FROM SUNDAY AFTERNOON INTO MONDAY EVENING...THE FOCUS WILL SHIFT
FOR RAIN TO WIND AND COLD. ONCE THE COLD FRONT MOVES THROUGH
SUNDAY AFTERNOON...NORTHWEST WIND WILL REALLY INCREASE WITH GUSTS
WELL ABOVE 30 MPH BY SUNDAY EVENING. WINDS WILL DROP LITTLE ON
SUNDAY NIGHT AND THEN PICK BACK UP WITH SUSTAINED WINDS OVER 20
MPH ON MONDAY. TEMPERATURES WILL FALL FAIRLY QUICKLY SUNDAY NIGHT
WITH LOWS IN THE 30S TO LOW 40S. ON MONDAY...THERE WILL BE A LOT
OF LOW LEVEL MOISTURE AROUND SO EVEN IF THERE IS SOME BREAKS IN
CLOUDS MONDAY MORNING...WITH 850 MB TEMPS BELOW ZERO...SUNSHINE
WILL BE SELF DESTRUCTIVE AND SKIES IN MOST AREA WILL BECOME CLOUDY
BY LATE MORNING. MOST PLACES WILL LIKELY REACH HIGHS IN THE 40S TO
MID 50S BY EARLY AFTERNOON AND THEN HOLDING STEADY. AT THIS POINT
THE GFS BUFR SOUNDINGS SHOW A VERY SHALLOW UNSTABLE LAYER SO NOT
EXPECTING SHOWERS TO DEVELOP BUT WILL NEED TO MONITOR THE
POTENTIAL AS NAM/ECMWF SOUNDINGS WOULD SUPPORT A MIX OF GRAUPAL
AND RAIN IN PORTIONS OF SW MN AND EAST CENTRAL SD.
IN THE LONGER RANGE...MONDAY NIGHT THROUGH FRIDAY...BELOW NORMAL
TEMPERATURES ARE EXPECTED TO CONTINUE. THE MODELS HAVE A GENERAL
AGREEMENT WITH A LONG WAVE TROUGH OVER THE AREA THROUGH THE WEEK.
THE BEST CHANCE OF RAIN WILL BE ON LATE TUESDAY NIGHT AND
WEDNESDAY BUT THERE IS SOME QUESTION HOW FAR EAST THE RAIN WILL
GET AS EASTERLY FLOW FROM HIGH PRESSURE WILL ACT TO LIMIT MOISTURE
FLOW INTO THE AREA AND MAY PREVENT RAIN FROM REACHING SW MN AND
PORTIONS OF NW IA. TEMPERATURES THROUGH WEDNESDAY WILL BE IN THE
50S WITH UNSEASONABLY COLD AIR BOTH DAYS AND CLOUDS AND RAIN ON
WEDNESDAY. A GRADUAL WARM UP WILL BEGIN ON THURSDAY AND CONTINUE
INTO FRIDAY ALTHOUGH IT IS MOST LIKELY HIGHS WILL REMAIN IN THE
60S. A STRONGER WAVE WILL ALSO APPROACH LATER FRIDAY WHICH MAY
BRING A CHANCE OF THUNDERSTORMS BY AFTERNOON. HOWEVER...THE BETTER
CHANCE WILL BE INTO MEMORIAL DAY WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1107 PM CDT FRI MAY 15 2015
CURRENTLY...MVFR TO VFR CONTINUES TO DOMINATE THE SIOUX FALLS
FORECAST AREA. MOST OF THE MVFR IS BOTTLED UP ALONG AND NORTH OF I
90 WITH PRIMARILY VFR SOUTH OF I 90. OVERALL CONFIDENCE IS LOW
WITH THE 06Z SET OF TAFS WITH THE DETAILS. MODELS INCLUDING THE
LATEST NAM/GFS AND GEM REGIONAL CONTINUE TO SHOW A LOT OF LOW
LEVEL HUMIDITY BUILDING BACK IN BETWEEN 06Z AND 12Z TONIGHT BUT
HOW MUCH OF THIS IS BELIEVABLE REMAINS TO BE SEEN. TAKEN
LITERALLY...ALL OF THE TAF SITES WOULD GO IFR IF NOT LIFR BY 09Z
OR 10Z SATURDAY. WITH A RELATIVELY DRY EAST TO SOUTHEAST FLOW OF
AIR AM NOT BUYING THAT TOTALLY...AND OPTED TO HEDGE AND PUT IN
MVFR INSTEAD FOR NOW. THERE COULD BE ONE BAND OF RAIN MOVING
THROUGH SOUTHEAST SD AND EAST CENTRAL SD EARLY SATURDAY
MORNING...AND AGAIN ACROSS PARTS OF THE AREA LATE SATURDAY
AFTERNOON. FOR NOW...LEFT OUT THE MENTION OF THUNDERSTORMS AS
ELEVATED INSTABILITY IS ABUNDANT...BUT REMAINS TOO SKITTISH TO
MENTION AT A POINT LOCATION. AND A BULK OF THE ORGANIZED RAINFALL
WHEN THERE WILL BE THUNDERSTORMS FOR SURE DOES NOT OCCUR UNTIL IT
IS ON SIOUX CITY`S DOORSTEP TOWARD THE END OF THE TAF PERIOD. SO
AGAIN...LEFT IT OUT FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...DUX
LONG TERM...SCHUMACHER
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1133 PM CDT FRI MAY 15 2015
.UPDATE...
06 TAF DISCUSSION.
&&
.AVIATION...
LINE OF STORMS CROSSING TN RIVER WILL REACH CKV AROUND START OF
TAF PERIOD. LEANED HEAVILY ON LATEST HRRR FOR TIMING...AND EXPECT
-SHRA TO CONTINUE AT CKV THROUGH THE NIGHT...REACHING BNA BY 12Z
AND CSV BY 14Z. MIX OF -SHRA/-TSRA EXPECTED BY 15Z AT ALL
AIRPORTS AS INSTABILITY INCREASES WITH DAYTIME HEATING...WITH
-SHRA/-TSRA CONTINUING TO 16/21Z. VFR CIGS TO BECOME MVFR BY 15Z
AS PRECIP BECOMES MORE WIDESPREAD. LIGHT SOUTH WINDS ANTICIPATED
THROUGH THE TAF PERIOD WITH OCCASIONAL GUSTS TO 20 KNOTS.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 635 PM CDT FRI MAY 15 2015/
UPDATE...
IMPULSE TO RIDE NORTHEAST AND INFLUENCE THE WEATHER OVER THE MID
STATE TONIGHT. BEST PVA TRAJECTORY APPEARS TO BE OVER WESTERN
AREAS. FURTHERMORE...DEEPEST MOISTURE TO POOL OVER THAT REGION AS
WELL. LATEST RADAR TRENDS SHOWS SOME INITIAL CONVECTION KNOCKING
AT THE DOOR ALONG THE TN RIVER. WILL GO AHEAD AND UPDATE THE ZONES
TO REMOVE THE LATE AFTERNOON WORDING. ALSO...WILL INCREASE POPS TO
THE LIKELY LEVEL FAR WEST...WILL INCLUDE 50 POPS CENTRAL AREAS.
OTW...HUMID AIRMASS SHOULD PREVENT TEMPS FROM DROPPING MUCH
OVERNIGHT. MIN TEMPS SHOULD HOLD IN THE 60S SO NO CHANGES NEEDED.
UPDATE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 623 PM CDT FRI MAY 15 2015/
AVIATION 00Z DISCUSSION...
SHOWER AND TSTM ACTIVITY WILL MAKE A RUN AT THE AREA...MAINLY AFT
06Z. THE CATALYST WILL BE AN OVERNIGHT SHORTWAVE WHICH WILL BE
RIDING NORTHWESTWARD THROUGH THE MID STATE. CIGS WILL LOWER
OVERNIGHT AND VSBYS SHOULD GENERALLY REMAIN AT 3SM OR GREATER.
CONVECTIVE COVERAGE WILL DECREASE AFT 18Z.
PREV DISCUSSION... /ISSUED 238 PM CDT FRI MAY 15 2015/
DISCUSSION...AFTER MORE THAN 2 WEEKS WITHOUT SIGNIFICANT RAIN FOR
MOST OF MID TN...SCATTERED THUNDERSTORMS HAVE DEVELOPED. THE
POTENTIAL FOR WET WX WILL CONTINUE THROUGHOUT THE WEEKEND...
ESPECIALLY ON SATURDAY. THIS IS GOOD NEWS TO MANY...BUT LOTS OF
OUTDOOR EVENTS WILL BE IN JEOPARDY.
FOR THE REMAINDER OF TODAY...SCATTERED SHOWERS AND STORMS WILL
CONTINUE WITH POPS AROUND 40 PERCENT. NO SIGNIFICANT BOUNDARIES
ARE EVIDENT TO INDICATE ANY SPECIFIC LOCATIONS THAT WILL BE
IMPACTED. THE ACTIVITY WILL TEND TO DIMINISH AS THE SUN SETS THIS
EVENING.
OVERNIGHT...A FEW SHOWERS OR STORMS WILL LINGER...AND THE ACTIVITY
MAY INCREASE AGAIN TOWARD DAYBREAK. A FEW AREAS OF FOG ARE POSSIBLE
WITH LOWS IN THE MUGGY 60S.
FOR SATURDAY...ALL SIGNS POINT TO LOTS OF SHOWERS AND THUNDERSTORMS.
LOW LEVEL SOUTHERLY FLOW WILL CONTINUE TO BRING MOIST AIR FROM THE
GULF WHILE SOUTHWEST FLOW ALOFT ADDS MOISTURE AND A COUPLE OF
SHORTWAVE TROUGHS. PRECIPITABLE WATER VALUES WILL APPROACH 2
INCHES...ESPECIALLY OVER OUR NORTHWEST COUNTIES. THE GREATEST
RAINFALL COVERAGE WILL BE SATURDAY MORNING THROUGH EARLY
AFTERNOON WITH THE MAIN SHORTWAVE. AFTER THAT...THE COVERAGE WILL
DECREASE...BUT THERE WILL CONTINUE TO BE PLENTY OF MOISTURE AND
ADEQUATE INSTABILITY TO GENERATE CLUSTERS OF SHOWERS AND
THUNDERSTORMS. RAINFALL AMOUNTS FOR SATURDAY WILL RANGE FROM ONE
QUARTER TO ONE INCH...WITH THE HIGHER TOTALS EXPECTED GENERALLY
OVER THE NORTHWEST HALF OF MID TN. BECAUSE OF THE RAIN AND
CLOUDS...WE WILL GO ON THE LOW SIDE OF GUIDANCE TEMPERATURES FOR
SATURDAY.
THE COVERAGE OF SHOWERS AND STORMS WILL DECREASE SATURDAY NIGHT
THROUGH SUNDAY...TO 40-50 PERCENT. CONDITIONS WILL REMAIN QUITE
MUGGY WITH LOWS IN THE MID TO UPPER 60S. LOWER RAIN COVERAGE AND
SOME INTERVALS OF SUNSHINE WILL BRING WARMER TEMPS ON
SUNDAY...MAINLY LOW TO MID 80S.
RAIN CHANCES WILL INCREASE AGAIN SUNDAY NIGHT INTO MONDAY AS A
COLD FRONT APPROACHES. ANOTHER QUARTER TO 1 INCH OF RAINFALL IS
EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. FORTUNATELY...WE DO
NOT EXPECT ANY WIDESPREAD OR ORGANIZED SEVERE WX.
COOLER AND DRIER AIR WILL FOLLOW THE FRONT FOR MIDWEEK. A COUPLE
OF DISTURBANCES WILL BRING A SMALL CHANCE FOR SHOWERS BY THURSDAY
THEN TRENDING WARM AND UNSETTLED AGAIN FOR NEXT WEEKEND.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION
NWS TAUNTON MA
716 AM EDT SAT MAY 16 2015
.SYNOPSIS...
SCATTERED SHOWERS THIS MORNING AS A WARM FRONT MOVES ACROSS THE
REGION. WARM AND MORE HUMID WEATHER FOLLOWS 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 PM THIS EVENING/...
715 AM UPDATE...
BATCH OF SHOWERS MOVING EWD THROUGH CT THIS MORNING WILL BE
FOCUSED MAINLY ALONG THE CT S COAST TO COASTAL RI...WITH ISOLD
SHOWERS POSSIBLE REMAINDER OF SNE THIS MORNING. SOME ELEVATED
INSTABILITY EXISTS AND NOTED SOME LIGHTNING EARLIER ACROSS SE NY
SO CANT RULE OUT AN ISOLD TSTM ACROSS S COASTAL RI. HRRR SUGGESTS
SHOWERS EXITING THE REGION BY MIDDAY. UPDATED POPS TO REFLECT
CURRENT RADAR TRENDS.
PREVIOUS DISCUSSION...
AFTER THIS MORNING...EXPECT LITTLE IN THE WAY OF PRECIP FOR THE
REMAINDER OF THE DAY. THE EXCEPTION TO THIS COULD BE LATE IN THE
DAY CONVECTION FROM WESTERN NEW YORK STATE/PENNSYLVANIA COULD MOVE
EASTWARD INTO THE SOUTHWESTERN PORTIONS OF SOUTHERN NEW ENGLAND.
WITH MOSTLY CLOUDY SKIES MUCH OF THE DAY AND DIMINISHING DAYTIME
INSTABILITY...EXPECT A FEW SHOWERS TO BE THE EXTENT OF THE PRECIP
REACHING THIS AREA.
TEMPERATURE FORECAST IS A BIT COMPLICATED. WHILE NOT EXPECTING
WIDESPREAD PRECIP TODAY...DO EXPECT SKY TO REMAIN MOSTLY CLOUDY TO
OVERCAST. THIS COULD LIMIT TEMPERATURES SOMEWHAT...THOUGH ANY PEEKS
OF SUN WILL ALLOW TEMPS TO JUMP UP. FOR NOW...WENT AGAIN WITH THE
HIRES GUIDANCE WHICH GAVE HIGH TEMPS AROUND 70 FOR MUCH OF THE
REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...UPPER RIDGE CONTINUES TO BUILD INTO THE NORTHEAST U.S.
WHILE THE WARM FRONT CONTINUES TO MOVE NORTH OF SOUTHERN NEW
ENGLAND. ASIDE FROM THE FEW SHOWERS MENTIONED ABOVE...EXPECT MUCH
OF THE NIGHT TO BE DRY. OVERCAST SKIES CONTINUE...INSULATING US
FROM ABOVE. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE UPPER 50S TO
AROUND 60.
SUNDAY...THE BACK DOOR COLD FRONT HAS SLOWED SUBSTANTIALLY SINCE
LAST NIGHTS MODEL RUNS. THIS WILL LEAD TO A MUCH WARMER DAY THAN
PREVIOUSLY FORECAST. UPPER RIDGE HOLDS STRONG ACROSS THE NORTHEAST
AND SEABREEZES ARE LIKELY TO DEVELOP WITH LIGHT FLOW ALOFT. THIS
WILL KEEP TEMPERATURES ALONG THE IMMEDIATE COAST IN THE MID TO UPPER
60S. HOWEVER...FARTHER INLAND...HIGHS SHOULD CLIMB INTO THE LOW 80S
FOR MOST LOCATIONS. EXPECT MOSTLY SUNNY SKIES AS WELL WITH DIURNAL
CU FORMING DURING THE AFTERNOON HOURS. SHOULD BE THE PICK OF THE
WEEKEND.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HIGHLIGHTS...
* MAINLY DRY AND 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
OVERVIEW...
MODELS ARE IN GOOD AGREEMENT ON THE LARGE SCALE FLOW DURING THE
EXTENDED PERIOD. MID LEVEL SHORTWAVE MOVING S FROM NOVA SCOTIA WILL
BRING A BACKDOOR FRONT ACROSS SNE SUN NIGHT WHICH WILL USHER IN A
MUCH COOLER MARITIME AIRMASS LATE SUN NIGHT INTO MON. THEN NEXT MID
LEVEL TROF MOVES EAST FROM THE UPPER MIDWEST WHICH WILL LIKELY BRING
A PERIOD OF SHOWERS MON NIGHT AND ESPECIALLY TUE. THIS TROF WILL
SETTLE ACROSS SE CANADA MID TO LATE WEEK BRINGING MAINLY DRY AND
SEASONABLE WEATHER.
SUN NIGHT AND MON...
BACKDOOR FRONT MOVES ACROSS SNE SUN NIGHT AS STRONG RIDGE NOSES DOWN
FROM THE MARITIMES TO THE GULF OF MAINE. LOW LEVEL NE FLOW WILL LEAD
TO INCREASING LOW LEVEL MOISTURE AND AN EXPANSION OF STRATUS AND
PATCHY FOG LATE SUN NIGHT INTO EARLY MON ALONG WITH THE POSSIBILITY
OF SOME PATCHY DRIZZLE. CLOUDS SHOULD LIFT AND GIVE WAY TO PTSUNNY
SKIES BY MON AFTERNOON...BUT CLOUDS COULD LINGER ALONG THE COAST.
WITH DEVELOPING SUNSHINE HIGHS ON MON SHOULD RECOVER INTO THE
MID/UPPER 60S AND SOME LOWER 70S CT VALLEY...BUT CLOSER TO 60 ALONG
E COASTAL MA.
MON NIGHT INTO TUE...
DEEPENING MOISTURE PLUME AHEAD OF APPROACHING COLD FRONT MOVES INTO
SNE LATE MON NIGHT AND TUE. MODEST LOW LEVEL JET ACTING ON 1.5"+
PWATS ALONG WITH MARGINAL ELEVATED INSTABILITY WILL RESULT IN A
PERIOD OF SHOWERS AND PERHAPS AN ISOLD TSTM LATE MON NIGHT INTO TUE.
TIMING NOT CERTAIN AT THIS TIME RANGE BUT IT APPEARS BEST CHANCE OF
SHOWERS WILL BE DURING TUE...ESPECIALLY AFTERNOON ACROSS E NEW ENG.
HIGHS TUE IN THE 60S. A FEW SHOWERS COULD LINGER INTO TUE EVENING
ALONG THE COAST...OTHERWISE DRYING MOVES IN TUE NIGHT BEHIND THE
FRONT.
WED THROUGH FRI...
LONG WAVE TROF SETS UP ACROSS SE CANADA WITH HIGH PRES IN CONTROL
LEADING TO MAINLY DRY AND SEASONABLE CONDITIONS.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY/...
TODAY...HIGH CONFIDENCE. MAINLY VFR. A FEW SHOWERS THIS MORNING
WITH BRIEF MVFR VSBY POSSIBLE ESPECIALLY CT AND S RI.
TONIGHT...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR
CONDITIONS IN LOW CLOUDS AND PATCHY FOG.
SUNDAY...HIGH CONFIDENCE. VFR. SEABREEZES DEVELOP ALONG THE EAST
AND SOUTH COASTS ABOUT 14-15Z.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
SUN NIGHT AND MON...MODERATE CONFIDENCE. WINDS BECOMING NE FROM E TO
W SUN NIGHT BEHIND A BACKDOOR FRONT WITH IFR STRATUS AND PATCHY FOG
DEVELOPING LATE SUN NIGHT INTO MON MORNING...THEN IMPROVING TO VFR
MON AFTERNOON BUT MVFR CIGS MAY LINGER ALONG THE COAST.
MON NIGHT AND TUE...MODERATE CONFIDENCE. AREAS OF MVFR/IFR
REDEVELOPING WITH SCT TO NUMEROUS SHOWERS AND POSSIBLY A
TSTM...ESPECIALLY TUE.
WED...MODERATE CONFIDENCE. VFR. 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 SUNDAY/...HIGH CONFIDENCE.
QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE OVER THE
WATERS. SOUTHERLY WINDS 10 TO 15 KTS THROUGH THE PERIOD WITH GUSTS
TO 20 KTS TODAY...SHIFTING TO LIGHT AND VARIABLE SUNDAY.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
SUN NIGHT AND MON...HIGH CONFIDENCE. A PERIOD OF NE GUSTS TO 20 KT
LIKELY LATE SUN NIGHT INTO EARLY MON...WITH E WINDS MON AFTERNOON
TURNING SOUTHERLY MON NIGHT. VSBYS MAY BE REDUCED IN PATCHY FOG.
TUE...HIGH CONFIDENCE. PREFRONTAL S/SW WINDS INCREASING TO 20 KT
INTO TUE EVENING WITH LOW PROB FOR A FEW G25 KT...THEN SHIFTING TO
NW LATE MON NIGHT BEHIND FROPA. SHOWERS AND PATCHY FOG WILL
REDUCE VSBYS.
WED...HIGH CONFIDENCE. W/NW WINDS WITH GUSTS TO 20-25 KT. MARGINAL
SCA CONDITIONS POSSIBLE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/RLG
NEAR TERM...KJC/RLG
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...KJC/RLG
MARINE...KJC/RLG
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1130 AM EDT SAT MAY 16 2015
.SYNOPSIS... 16Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN AMPLIFIED
UPPER LEVEL PATTERN OVER THE CONUS TODAY. DEEP AND POTENT UPPER
TROUGH IS SPINNING OVER THE INTERMOUNTAIN WEST/WESTERN PLAINS...WITH
DOWNSTREAM STRONG RIDGING ALOFT OVER THE EASTERN THIRD OF THE
NATION. WV IMAGERY SHOWS A STRONG SHORTWAVE ROUNDING THE BASE OF THE
WESTERN TROUGH AND ABOUT TO EJECT NORTHEASTWARD OVER THE CENTRAL
PLAINS. THIS ENERGY IS FORECAST TO BRING A POTENTIAL SIGNIFICANT
SEVERE WEATHER OUTBREAK TO PARTS OF TEXAS/OK/KS LATER TODAY. WHILE
THIS WEATHER SYSTEM AND ITS ASSOCIATED ORGANIZED SEVERE WEATHER
THREAT WILL STAY WELL TO OUR NORTHWEST THIS WEEKEND...WE IN WEST-
CENTRAL AND SOUTHWEST FLORIDA WILL BE DEALING WITH MORE OF OUR OWN
LATE DAY SEA-BREEZE STORMS. MORE INFO ON OUR THUNDERSTORM THREAT IN
THE SHORT TERM DISCUSSION BELOW.
ALREADY SEEING RAPID CUMULUS FIELD DEVELOPMENT ACROSS MUCH OF THE
PENINSULA LATE THIS MORNING...AND THIS SCT-BKN CLOUD FIELDS SHOULD
INVADE ALL OF OUR SKIES INTO THE EARLY AFTERNOON HOURS.
AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO
THE WEST INTO THE GA/CAROLINA COAST...PROVIDING OUR REGION WITH A
GENERAL EAST TO SOUTHEAST LOW LEVEL FLOW. SIMILAR TO PREVIOUS
DAYS...THIS EASTERLY SYNOPTIC FLOW WILL FAVOR THUNDERSTORM
DEVELOPMENT ALONG THE FLORIDA WEST COAST SEA-BREEZE DUE TO THE ADDED
CONVERGENCE AND EVENTUAL ARRIVAL/COLLISION OF THE EAST COAST SEA-
BREEZE BOUNDARY.
&&
.SHORT TERM (REST OF TODAY THROUGH SUNDAY)...
REST OF TODAY... WITHIN THE LARGE SCALE PRESSURE GRADIENT ON THE
SOUTHERN PERIPHERY OF THE ATLANTIC RIDGE TO OUR NORTH...WE CAN
ANALYZE A WEAK INVERTED TROUGH/CONVERGENCE ZONE ALONG THE SOUTHEAST
FL COAST. WILL SEE A SCATTERING OF SHOWERS BEGIN TO MIGRATE
WESTWARD FROM THIS FEATURE INTO THE SOUTH-CENTRAL ZONES
(HIGHLANDS/HARDEE/DESOTO) DURING THE EARLY AFTERNOON...AND
EVENTUALLY OVER TOWARD THE PUNTA GORDA/FORT MYERS AREA. MAY SEE A
BRIEF SHOWER FROM THIS ACTIVITY...BUT THE MAIN CONVECTIVE
DEVELOPMENT IS NOT EXPECTED UNTIL LATER IN THE AFTERNOON/EARLY
EVENING HOURS. BEFORE THE EXPECTED CONVECTIVE BURST...MUCH OF THE
REGION WILL SEE A MIX OF SUN AND CLOUDS WITH TEMPERATURES CLIMBING
THROUGH THE 80S.
FORECASTING SEA-BREEZE THUNDERSTORMS IS NEVER A PERFECT SCIENCE...
BUT HERE IS THE BREAKDOWN LEADING TO THE CURRENT FORECAST. WE START
WITH THE SYNOPTIC LOW LEVEL (1000-700MB) FLOW...WHICH TODAY IS
MODERATE FROM THE EAST/SOUTHEAST. THIS FLOW REGIME DURING THE WARM
SEASON FAVORS LATE DAY THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA
WEST COAST...WITH DRIER CONDITIONS BY LATE AFTERNOON FOR THE FLORIDA
EAST COAST. THE WEST COAST IS FAVORED DUE TO THE ENHANCED
CONVERGENCE OF THE LARGE SCALE FLOW HEADING WESTWARD...AND THE WEST
COAST SEA-BREEZE TRYING TO MOVE EAST. EVENTUALLY THE EAST COAST SEA-
BREEZE...SPED ALONG BY THE LARGE SCALE FLOW ARRIVES AT THE I-75
CORRIDOR AND FURTHER ENHANCES THE LOW LEVEL FOCUS/CONVERGENCE.
ALOFT...THERE IS NOT REALLY ANY SIGNIFICANT HOSTILE LAYER TOWARD
DEEP CONVECTION...WITH MINIMUM THETAE VALUES NO LOWER THAN AROUND
320K (FAIRLY TYPICAL FOR MID MAY).
THE CURRENT FORECAST FAVORS THE HIGHEST RAIN CHANCES LATE
AFTERNOON/EVENING FROM TAMPA BAY SOUTHWARD DUE TO THE FACT THAT THE
FLOW JUST ALOFT OFF THE SURFACE SEEMS TO BE A BIT STRONGER FOR THE
NATURE COAST...AND IS BORDERLINE STRONG ENOUGH TO PREVENT AN
ORGANIZED SEA-BREEZE...OR TO KEEP IT SUPPRESSED JUST OFFSHORE.
LIGHTER FLOW FURTHER SOUTH SHOULD ALLOW SOME INLAND PENETRATION OF
THE SEA-BREEZE CIRCULATION SO THAT THE MORE EFFICIENT LOW LEVEL
FOCUS ZONE TO ENHANCE LIFT APPEARS TO SET UP FROM PASCO/PINELLAS
COUNTIES SOUTHWARD. THERE IS ACTUALLY VERY GOOD AGREEMENT AMONG THE
HIRES CONVECTION ALLOWING GUIDANCE FROM NCEP AND LOCAL RUNS TO
SUPPORT THIS SCENARIO. IN FACT...THE LAST FEW RUNS OF THE HRRR HAVE
BEEN FOCUSING MAINLY FROM MANATEE COUNTY SOUTHWARD. SINCE...THE
HIRES GUIDANCE ARE SUBJECT TO INFLUENCE FROM THEIR OWN EARLIER
CONVECTION...AND THE PARAMETERIZED MODELS ARE STILL SHOWING
DEVELOPMENT A BIT FURTHER NORTH...HAVE INCLUDED THE TAMPA BAY/PASCO
AREA IN THE LIKELY RAIN/THUNDER CHANCES. WILL SEE HOW ALL THIS WORKS
OUT AS WE GET LATER INTO THE DAY...BUT BASED ON ALL AVAILABLE INFO
AND PATTERN RECOGNITION...FEEL THIS IS THE BEST FORECAST.
HAVE ALSO BEEN FAIRLY IMPRESSED WITH THE GENERAL UPDRAFT VELOCITY
VALUES OUT OF THE HRRR FOR LATER TODAY. PEAK VALUES SOUTH OF TAMPA
BAY HAVE BEEN IN THE 15-20M/S RANGE...WHICH IS FAIRLY SUBSTANTIAL
FOR LOW SHEAR PULSE CONVECTION. WITH THIS IN MIND WILL NEED TO BE
MINDFUL OF PRECIP LOADING AND DOWNBURST POTENTIAL WITH STRONGER
CELLS. ALSO...THE POTENTIAL FOR SOME EFFICIENT LIGHTNING PRODUCERS
IS ALSO THERE.
WHAT IS LEFT OF THE STORMS PUSH OFFSHORE INTO THE COASTAL WATERS BY
LATE EVENING...FOLLOWED BY A GENERALLY QUIET...DRY AND SEASONABLY
WARM OVERNIGHT PERIOD.
SUNDAY... WE SEE ONE MORE DAY WITH THIS BROKEN RECORD PATTERN OF
EASTERLY SYNOPTIC FLOW. ONE THING ADVERTISED BY THE CURRENT MODEL
SUITE...IS A MORE UNIFORM LIGHT FLOW ABOVE THE SURFACE FOR THE
AFTERNOON HOURS...RESULTING IN A MORE UNIFORM ORGANIZATION TO THE
SEA-BREEZE ALONG OUR COASTS. THEREFORE...AFTER A QUIET MORNING AND
EARLY AFTERNOON...YET ANOTHER ROUND OF LATE DAY STORMS IS
ANTICIPATED ALONG THE I-75 CORRIDOR. AS IT STANDS NOW...APPEARS WE
SHOULD SEE A SCATTERING OF SHOWERS/STORMS PROGRESS FROM EAST TO WEST
ACROSS THE FORECAST AREA ALONG THE EAST COAST SEA BREEZE DURING THE
EARLY/MID AFTERNOON...WITH CONVECTION RAMPING UP TO NUMEROUS
THUNDERSTORMS ALONG AND INSIDE THE I-75 CORRIDOR AFTER AROUND 400 PM.
THE SYNOPTIC PATTERN FINALLY BEGINS TO TRANSITION TO A MORE WESTERLY
FLOW REGIME EARLY NEXT WEEK...WHICH SHOULD SHIFT THE HIGHER RAIN
CHANCES AWAY FROM THE COAST TOWARD THE INLAND AREAS/FL EAST COAST.
&&
.AVIATION... CONDITIONS ARE QUIET WITH PREVAILING VFR ONGOING LATE
THIS MORNING ACROSS WEST CENTRAL AND SW FLORIDA. HOWEVER...THESE
CALM CONDITIONS ARE NOT EXPECTED TO LAST THE REMAINDER OF THE DAY.
SIMILAR TO PREVIOUS DAYS...RAPID THUNDERSTORM DEVELOPMENT IS EXPECTED
ALONG THE I-75 CORRIDOR AFTER 20Z...WITH STORMS THEN PUSHING SLOWLY
TO THE WEST. A PERIOD OF IFR OR LOWER VIS/CIGS ALONG WITH GUSTY
WINDS AND FREQUENT LIGHTING IS POSSIBLE FOR ANY TERMINAL LATER
TODAY. WILL ADD THUNDER TEMPO GROUPS WITH 18Z PACKAGE.
&&
.MARINE...
A GENERAL EAST TO SOUTHEAST WINDS FLOW WILL REMAIN IN
PLACE THROUGH SUNDAY WITH WINDS TURNING ONSHORE AT THE COAST EACH
AFTERNOON AS THE SEA BREEZE DEVELOPS. THUNDERSTORMS ARE EXPECTED
TO RAPIDLY DEVELOP NEAR THE COAST DURING THE LATE AFTERNOON AND
EVENING HOUR BOTH TODAY AND SUNDAY...THEN PUSH OFFSHORE DURING THE
NIGHTIME HOURS. BOATERS ENJOYING THE COASTAL WATERS OF THE FLORIDA
WEST COAST SHOULD KEEP AND EYE TO THEIR EAST DURING THE LATE DAY
HOURS THIS WEEKEND...AND BE PREPARED TO SEEK SAFE HARBOR SHOULD
THREATENING WEATHER ADVANCE. HEADING THROUGH THE UPCOMING WORK
WEEK...WINDS WILL SHIFT MORE WESTERLY...KEEPING MOST OF THE
THUNDERSTORM ACTIVITY INLAND.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE
HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 73 89 73 / 60 30 60 20
FMY 91 72 90 72 / 70 40 60 20
GIF 90 72 90 71 / 30 10 50 10
SRQ 88 72 88 72 / 70 40 60 20
BKV 90 70 89 69 / 50 20 60 10
SPG 89 75 89 75 / 60 40 60 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/AVIATION/FIRE WX...MROCZKA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
948 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 947 AM CDT SAT MAY 16 2015
SHOWERS INCREASING IN COVERAGE TO OUR SOUTH...AND HAVE SEEN
SCATTERED SHOWERS ALSO DEVELOPING MORE WITHIN OUR FORECAST AREA.
SO FAR THUNDER UPSTREAM HAS BEEN RATHER MINIMAL...AND SURFACE
BASED CAPE VALUES PROGGED BY THE RAP MODEL EXPECTED TO BE LESS
THAN 500 J/KG FROM ABOUT I-57 EASTWARD. WITH NO SUBSTANTIAL
HEATING IN THAT AREA...HAVE DOWNPLAYED THE THUNDER POTENTIAL
ACROSS THE EASTERN CWA THROUGH THE AFTERNOON. FURTHER WEST...
CAPES 1000-1500 J/KG EXPECTED AND THERE ARE ALSO SOME SUBSTANTIAL
BREAKS IN THE CLOUDS ACROSS SOUTHERN IOWA AND NORTHEAST
MISSOURI...SO HAVE MAINTAINED GENERAL SHOWER/THUNDERSTORM MENTION
ACROSS THE REMAINDER OF THE FORECAST AREA. WITH RAIN ACROSS THE
SOUTHEAST CWA EXPECTED TO BECOME FAIRLY WIDESPREAD...HAVE LOWERED
HIGHS IN THAT AREA A COUPLE DEGREES...WITH MOST OF THE REMAINING
CWA GENERALLY EXPECTED TO REACH AROUND 80 DEGREES.
&&
.SHORT TERM...(TODAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
ANOTHER RELATIVELY WARM AND HUMID DAY IS ANTICIPATED ACROSS CENTRAL
AND SOUTHEAST ILLINOIS TODAY AS SOUTHERLY LOW LEVEL FLOW PERSISTS.
DAYTIME HIGHS MAY BE A FEW DEGREES COOLER THAN YESTERDAY, ESPECIALLY
ACROSS SOUTHEAST ILLINOIS WHERE CLOUD COVER WILL BE THICKEST AND
RAINFALL MOST WIDESPREAD, BUT MOST LOCATIONS SHOULD STILL CRACK THE
80 DEGREE MARK.
AS FAR AS SHOWER/STORM POTENTIAL TODAY, GIVEN THE FAIRLY JUICED UP
LOW-LEVEL AIRMASS AND LACK OF APPRECIABLE CAPPING, IT WILL NOT TAKE
MUCH TO POP OFF SOME CONVECTION. PLAN TO CARRY AT LEAST CHANCE POPS
AREAWIDE TODAY GIVEN THIS POTENTIAL. MODEL PROGS SUGGEST MOST OF THE
FORECAST AREA SHOULD SEE DIURNALLY INDUCED CAPE VALUES OF AT 1500
J/KG, ALTHOUGH SHEAR PROFILES SHOULD BE QUITE WEAK OVER THE NORTHERN
2/3 OR SO OF THE REGION. THE BETTER FORCING ACROSS SOUTHEAST
ILLINOIS WILL COME COURTESY OF A WEAK SHORT WAVE LIFTING NORTHEAST
FROM THE MID-MISSISSIPPI RIVER VALLEY. HAVE BUMPED POPS UP TO
CATEGORICAL SOUTH OF I-70 FOR THE MIDDAY/EARLY AFTERNOON HOURS TO
ACCOUNT FOR THE PASSAGE OF THIS WAVE.
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
DIURNALLY ENHNANCED CONVECTION THIS AFTERNOON AND EARLY EVENING WILL
DIMINISH IN COVERAGE AFTER SUNSET SIMILAR TO WHAT HAPPENED FRIDAY
EVENING AS INSTABILITY WANES. WILL CARRY HIGHEST POPS IN
SOUTHEAST IL THIS EVENING ESPECIALLY BEFORE DARK WITH SHORT WAVES
NEAR EASTERN/SE IL EARLY THIS EVENING AROUND 00Z/7 PM. MILD LOWS
TONIGHT IN THE MID TO UPPER 60S WITH MILDEST READINGS SW AREAS.
CUTOFF LOW OVER THE CENTRAL ROCKIES TO EJECT NE INTO MN BY SUNDAY
EVENING AND HAS A PREFRONTAL TROF PUSHING EAST TOWARD THE MS RIVER.
THIS TO INCREASE CHANCES OF CONVECTION FROM WEST TO EAST DURING THE
DAY SUNDAY AND THEN DIMINISH FROM WEST TO EAST DURING SUNDAY NIGHT.
SPC HAS SLIGHT RISK OF SEVERE STORMS SUNDAY AFTERNOON/EVENING FROM
BLOOMINGTON TO TAYLORVILLE WEST WHERE STRONGER BULK SHEAR OF 35-45
KTS OCCURS ALONG WITH INCREASE INSTABILITY WITH CAPES PEAKING AROUND
2500 J/KG SUNDAY AFTERNOON. WARM HIGHS IN THE LOWER 80S SUNDAY WITH
BREEZY SSW WINDS AND MUGGY DEWPOINTS IN THE MID TO UPPER 60S.
MAIN COLD FRONT TO PUSH EAST ACROSS IL DURING MONDAY AND BRINGS BEST
CHANCES OF SHOWERS AND THUNDERSTORMS TO AREAS EAST OF I-55. SPC
KEEPS MARGINAL RISK OF SEVERE EAST OF IL OVER PARTS OF INDIANA ON
MONDAY. HAVE BUMPED UP THE HIGHS ON MONDAY A FEW DEGREES WITH MID
70S FROM IL RIVER NW TO LOWER 80S IN EASTERN IL.
DRIER...COOLER AND LESS HUMID AIR USHERS INTO IL DURING MONDAY NIGHT
AND TUE BEHIND THE COLD FRONT. LOWS MONDAY NIGHT RANGE FROM MID 40S
NW OF IL RIVER TO NEAR 55F FAR SE IL NEAR WABASH RIVER BY
LAWRENCVILLE. HIGHS TUE IN THE MID 60S CENTRAL IL AND 65-70F IN
SOUTHEAST IL. A COOL NIGHT AHEAD FOR TUE NIGHT WITH LOWS IN THE MID
TO UPPER 40S.
EXTENDED MODELS TRY TO BRING SOME QPF BACK INTO PARTS OF CENTRAL AND
ESPECIALLY SOUTHERN/SW IL WED AND THEN SUPPRESS IS SOUTHWARD BY THU
WITH SOME ENERGY EJECTING FROM THE UPPER LEVEL TROF/LOW NEAR CA AND
MOVING INTO THE MID/LOWER MS RIVER VALLEY. WILL KEEP POPS LOW FROM
WED-THU WITH MAINLY SLIGHT CHANCES, THOUGH SW AREAS HAVE CHANCE POPS
30-40% WED AND WED EVENING. HIGHS IN THE LOW TO MID 60S WED AND 65
TO 70F ON THU. TEMPS CONTINUE TO SLOWLY MODIFY FRIDAY WITH HIGHS
MAINLY IN THE LOWER 70S AND DRY CONDITIONS WITH WEAK HIGH PRESSURE
IN THE CENTRAL PLAINS AND RIDGING EAST TOWARD IL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 639 AM CDT SAT MAY 16 2015
AREAS OF IFR STRATUS AND FOG HAVE DEVELOPED ACROSS CENTRAL
ILLINOIS EARLY THIS MORNING. THIS STRATUS/FOG SHOULD BURN OFF
WITHIN THE NEXT FEW HOURS AS DIURNAL HEATING INCREASES. THEN,
ATTENTION TURNS TO AN UPPER LEVEL DISTURBANCE LIFTING NORTHEAST
INTO THE AREA. THIS DISTURBANCE SHOULD PRODUCE AT LEAST SCATTERED
SHOWERS/STORMS TODAY AS IT MOVES THROUGH, WITH KDEC & KCMI THE
MOST LIKELY OF THE LOCAL TERMINALS TO BE IMPACTED. HAVE INCLUDED A
4 HOUR TEMPO FOR THUNDER AT THOSE LOCATIONS DURING THE PREFERRED
TIME PERIOD, BUT ONLY INCLUDED A VCTS AT KPIA, KBMI, AND KSPI AS
THE STORM COVERAGE SHOULD BE MORE SPOTTY FURTHER WEST. CAN`T RULE
OUT SOME CONVECTION POPPING UP OUTSIDE THE FAVORED DIURNAL HEATING
PERIOD, WHICH OVERLAPS TODAY WITH THE PASSAGE OF THE DISTURBANCE,
BUT EXPECTED COVERAGE IS TOO LOW TO MENTION AT THIS TIME. AS THE
AIRMASS, CLOUD, AND WIND CONDITIONS SHOULD BE SIMILAR TONIGHT TO
EARLY THIS MORNING, PLAN TO HAVE IFR CONDITIONS DEVELOPING ONCE
AGAIN LATER TONIGHT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BAK
LONG TERM...07
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1022 AM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 1021 AM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN SCATTERED SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT AS A
STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM
CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES
THIS AFTERNOON WILL REACH AROUND 80...WITH LOW TEMPERATURES
TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE
FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST
MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST
CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO
FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH
CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS
SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE
SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS
WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER
OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE
MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS
WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER
SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO
CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT
SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT
EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR
TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME
ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO
WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 544 AM EDT SAT MAY 16 2015
THE COMBINATION OF LOW/MID LEVEL MOISTURE TRANSPORT AND SEVERAL
WEAK EMBEDDED WAVES IN SOUTHWEST FLOW HAS LED TO NARROW BAND OF
SHOWERS FROM KSBN TO NORTH OF KFWA EARLY THIS MORNING. THIS BAND
WILL LIFT NORTH OF KSBN BY 12Z. A LULL IS THEN EXPECTED IN TERMS
OF PRECIP COVERAGE FOR THE TERMINALS...ALTHOUGH ADDITIONAL
IMPULSES EJECTING OUT OF SOUTHERN MISSOURI/ARKANSAS WILL POSE A
THREAT FOR ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS FROM
LATE MORNING INTO THIS AFTERNOON. CURRENT INDICATIONS WOULD
SUGGEST A MORE FAVORABLE SHORT WAVE TRACK FOR NORTHEAST
INDIANA. THUS...GREATER CONVECTIVE COVERAGE MAY AFFECT KFWA LATER
THIS MORNING INTO THIS AFTERNOON. HOWEVER WITH LOW CONFIDENCE IN
TIMING AND POINT PROBABILITIES...WILL LIMIT MENTION TO VCSH AT
KFWA AT THIS TIME. LIGHT SOUTH WINDS THIS MORNING WILL BECOME
SOUTHWEST 10 TO 15 KNOTS WITH DIURNAL MIXING THIS MORNING...AND
THEN LIGHT SOUTH AGAIN TONIGHT. DID ADD SOME MVFR VSBYS AT KSBN
LATER TONIGHT IN CLOSER PROXIMITY TO OLD LOW LEVEL BOUNDARY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MCD
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
611 AM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 136 AM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY
SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST.
OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND.
HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 80...WITH LOW
TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE
FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST
MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST
CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO
FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH
CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS
SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE
SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS
WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER
OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE
MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS
WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER
SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO
CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT
SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT
EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR
TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME
ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO
WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 544 AM EDT SAT MAY 16 2015
THE COMBINATION OF LOW/MID LEVEL MOISTURE TRANSPORT AND SEVERAL
WEAK EMBEDDED WAVES IN SOUTHWEST FLOW HAS LED TO NARROW BAND OF
SHOWERS FROM KSBN TO NORTH OF KFWA EARLY THIS MORNING. THIS BAND
WILL LIFT NORTH OF KSBN BY 12Z. A LULL IS THEN EXPECTED IN TERMS
OF PRECIP COVERAGE FOR THE TERMINALS...ALTHOUGH ADDITIONAL
IMPULSES EJECTING OUT OF SOUTHERN MISSOURI/ARKANSAS WILL POSE A
THREAT FOR ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS FROM
LATE MORNING INTO THIS AFTERNOON. CURRENT INDICATIONS WOULD
SUGGEST A MORE FAVORABLE SHORT WAVE TRACK FOR NORTHEAST
INDIANA. THUS...GREATER CONVECTIVE COVERAGE MAY AFFECT KFWA LATER
THIS MORNING INTO THIS AFTERNOON. HOWEVER WITH LOW CONFIDENCE IN
TIMING AND POINT PROBABILITIES...WILL LIMIT MENTION TO VCSH AT
KFWA AT THIS TIME. LIGHT SOUTH WINDS THIS MORNING WILL BECOME
SOUTHWEST 10 TO 15 KNOTS WITH DIURNAL MIXING THIS MORNING...AND
THEN LIGHT SOUTH AGAIN TONIGHT. DID ADD SOME MVFR VSBYS AT KSBN
LATER TONIGHT IN CLOSER PROXIMITY TO OLD LOW LEVEL BOUNDARY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
***THIS FORECAST DISCUSSION FOCUSES ON SEVERE WEATHER POTENTIAL
TODAY...INCLUDING THE THREAT OF ANOTHER TORNADO OUTBREAK ACROSS THE
HIGH PLAINS.***
TODAY...WIDESPREAD OUTBREAK OF SEVERE WEATHER IS LIKELY AS MANY
PIECES COME TOGETHER. OVERALL...FEEL THIS IS ANOTHER DANGEROUS
SATURDAY WITH REGARDS TO SEVERE WEATHER AND CLOSE ATTENTION NEEDS TO
BE PAID TO LATEST FORECAST UPDATES. SURFACE LOW PRESSURE WILL
CONTINUE TO DEEPEN THROUGH THE AFTERNOON HOURS OVER SOUTHEAST
COLORADO WITH LITTLE ADVANCEMENT TO THE EAST FORECAST UNTIL AFTER
00Z/6 PM MDT. AHEAD OF THE SURFACE LOW...SOUTHEAST WINDS
INCREASE...BECOMING QUITE GUSTY. WITH THE POSITION OF THE LOW AND
INCREASING SOUTHEAST WINDS...DO NOT FORESEE AN OPPORTUNITY FOR THE
DRYLINE TO RACE EAST AS FORECAST BY MANY HIGH RESOLUTION GUIDANCE
MEMBERS. INSTEAD...HAVE USED THE LATEST NAM 12 AS THE BASIS FOR MY
FORECAST WHICH INDICATES A NEARLY STATIONARY DRYLINE. BY THIS
REASONING...MORE OF TRI-STATE REGION IS UNDER THREAT FOR A HIGHER
IMPACT DAY THAN PREVIOUSLY FORECAST. THIS THREAT MAY EVEN EXIST AS
FAR WEST AS PORTIONS OF NORTHEAST COLORADO.
THREATS:
THE THREATS TODAY ARE LARGE HAIL TO BASEBALL SIZE...DAMAGING WINDS
AS HIGH AS 70 MPH AND TORNADOES...SOME OF WHICH COULD BE
STRONG...LONG-TRACKED TORNADOES. HEAVY RAINS FROM TRAINING STORMS
ARE ALSO A CONCERN SO FLASH FLOODING IS A POSSIBILITY.
ADDITIONALLY...THESE STORMS WILL PROPAGATE QUICKLY WITH STORM
MOTIONS AS FAST AS 50 MPH POSSIBLE.
LOCATION:
THE HIGHEST CHANCE FOR VIOLENT SUPERCELL THUNDERSTORMS EXTENDS
GENERALLY EAST OF THE COLORADO BORDER. PLEASE SEE THE LATEST SPC
GRAPHICS FOR BETTER RESOLUTION AS WE STRONGLY AGREE WITH THEIR
ASSESSMENT FOR LOCATIONS OF THE ENHANCED AND MODERATE RISK AREAS.
TIMING:
THERE MAY BE A FEW ROUNDS OF SEVERE WEATHER THIS AFTERNOON. THE
FIRST...MOST SIGNIFICANT ROUND BEGINS SHORTLY AFTER NOON. THIS IS
WHEN SUPERCELL THUNDERSTORMS WILL DEVELOP ALONG THE DRYLINE AND
SPREAD EAST. ANOTHER LINE OF STORMS MAY DEVELOP ALONG THE DRYLINE
LATER IN THE AFTERNOON. FINALLY...SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP OVER CENTRAL COLORADO AND MOVE ON FROM THE WEST.
WHAT YOU NEED TO KNOW:
A TORNADO OUTBREAK SEEMS LIKELY TODAY FOR PORTIONS OF THE HIGH
PLAINS. CLOSE ATTENTION NEEDS TO BE PAID TO LATEST FORECAST UPDATES
AND WATCHES/WARNINGS AS THEY ARE ISSUED TODAY. STORMS...ONCE THEY
DEVELOP...WILL ALMOST INSTANTANEOUSLY BECOME SEVERE AND MOVE QUICKLY
NORTHEAST. RAPIDLY CHANGING CONDITIONS ARE EXPECTED SO PLEASE BE
AWARE OF THIS DEVELOPING WEATHER SITUATION.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 327 AM MDT SAT MAY 16 2015
LATEST GUIDANCE CONTINUES TO INDICATE AN ACTIVE PATTERN ACROSS THE HIGH
PLAINS TUESDAY THROUGH SATURDAY. AN UPPER LEVEL LOW WILL MOVE OUT OF
THE SOUTHWEST ON TUESDAY AND DEEPEN... CREATING A NEGATIVE TROUGH THAT
WILL MOVE NORTHEAST INTO THE REGION AS WE HEAD INTO WEDNESDAY. THE 0-
6KM SHEAR PROFILE IS STRONG WITH 55-65KT ON TUESDAY AND WEDNESDAY AS
INDICATED BY BOTH THE GFS AND ECMWF. CAPE VALUES CONTINUE TO
REMAIN MODEST WITH THE GLOBAL MODELS INDICATING 200-400 J/KG AT
BEST. THE LOW WILL MOVE NORTHWARD THROUGH THE DAY ON WEDNESDAY AND
THURSDAY WHICH WILL KEEP POPS IN THE REGION IN THE 20-40 PERCENT
RANGE. THE DEVELOPMENT OF SEVERE STORMS WILL BE LIMITED DUE TO THE
LOW CAPE AND WEAK THETA-E GRADIENTS HOWEVER WE CANNOT RULE OUT
STRONGER THUNDERSTORM DEVELOPMENT AS THE HIGH SHEAR REMAINS IN
PLACE.
A PERSISTENT TROUGH REMAINS IN PLACE IN THE SOUTHWEST LATE THURSDAY AND
EARLY FRIDAY. EARLY GUIDANCE FROM THE GFS AND ECMWF INDICATE A STRONG
LOW MOVING SOUTHEASTWARD OUT OF THE PACIFIC LATE FRIDAY AND INTO
SATURDAY WHICH WILL REINFORCE AND DEEPEN THIS TROUGH. AT THE SAME TIME
LONG FETCH RETURN FLOW WILL INCREASE CAPE VALUES ACROSS THE HIGH
PLAINS. CAPE VALUES ON SATURDAY WILL INCREASE TO 800-1200 J/KG WITH
LIMITED SHEAR OF 30-40KTS MAINLY IN THE SOUTHERN AREAS OF THE CWA. IT
IS VERY EARLY STILL HOWEVER WE CANNOT RULE OUT THE POSSIBILITY OF
SEVERE THUNDERSTORMS NEXT SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 545 AM MDT SAT MAY 16 2015
VFR CONDITIONS FORECAST THIS MORNING WITH SOUTHEAST WINDS
STRENGTHENING BY 15Z...BECOMING GUSTY. BY THIS AFTERNOON...AN
UNSTABLE ATMOSPHERE TAKES SHAPE WITH STRONG/SEVERE THUNDERSTORMS
DEVELOPING ALONG A DRYLINE. STORMS SHOULD IMPACT KGLD FIRST AND
KMCK AN HOUR OR TWO LATER. DRYLINE PUSHES THROUGH KGLD...ENDING
THE THREAT OF THUNDERSTORMS WHILE KMCK MAY SEE A PROLONGED PERIOD
OF THUNDERSTORM ACTIVITY WITH A FEW INDIVIDUAL ROUNDS PASSING
THROUGH. THUNDERSTORMS WILL BRING A THREAT OF MVFR CIGS AND IFR
VISIBILITIES DUE TO HEAVY RAIN. ONCE THIS DYNAMIC WEATHER SYSTEM
PUSHES NORTHEAST THIS EVENING...CLEARING SKIES AND NORTHWEST WINDS
ANTICIPATED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...RRH
LONG TERM...TML
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
634 AM CDT Sat May 16 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CDT SAT MAY 16 2015
A broad upper level low was located across NV, UT and AZ early this
morning. A 65KT mid level jet max was lifting northeast across
eastern NM into western KS. The strong ascent ahead of this jet max
has helped to develop a line of showers and thunderstorms from
central NE, south-southwest into west TX. Most numerical models show
this line weakening as it moves east into a more stable airmass
across eastern KS through the morning hours.
A stronger H5 trough located along the southern base of the upper
level low will lift northeast across eastern NM into the northern TX
PNHDL through the late morning hours. Several numerical models all
show an area of scattered to numerous thunderstorms developing ahead
of a surface dryline across the eastern TX PNHDL through the mid
and late morning hours. These storms lift northeast and intensify
through the early and mid afternoon hours, as they move northeast
across western OK into south central KS. The 5Z HRRR shows this area
of thunderstorms moving northeast into the western counties of the
CWA by 20Z. Most numerical models show the atmosphere destabilizing
early this afternoon across the CWA, after the weaker storms from
this morning dissipate or lift off to the northeast. the WRF runs,
NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks
fairly weak with most models forecasting less than 100m2/s2 of 0-1KM
SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS
during the afternoon. Therefore, the environment will be favorable
for severe thunderstorms this afternoon. Another question will be
the mode of convection. If a complex of storms develops across
northwest OK late this morning and maintains itself northeast
across the CWA than any tornado threat will be quite low. Though
stronger updrafts within a QLCS or complex of thunderstorms would
produce large hail and damaging wind gusts. The HRRR and NAM 4KM
simulated reflectivity forecast more scattered to isolated
thunderstorms developing across north central OK and south central
KS early this afternoon, and moving northeast into the southwest
and southern counties of the CWA after 22Z. I suppose if we see
discrete supercells than there will be a chance for tornadoes
along with the large hail and damaging wind gusts.
Late this afternoon most models show thunderstorms developing along
the Pacific front/dryline across west central KS and western OK. The
environment will really improve ahead of the dryline late this
afternoon, with much stronger low-level vertical wind shear. Any
discrete supercells that develop along the Pacific front/dryline
across west central KS and western OK will have a chance to produce
tornadoes. Through the evening hours these discrete to scattered
supercell thunderstorms may congeal into line segments or a QLCS and
move northeast into the western counties of the CWA during the mid
evening hours. If discrete supercells move into the western counties
this evening, then there will be a chance for tornadoes. I suppose
if a QLCS develops there is a potential for meso-vortices tornadoes.
Cloud cover will probably keep high temperatures in the mid to
upper 70s.
Tonight, The upper low and lead H5 trough will lift northeast into
southwest NE. Line segments of thunderstorms or a QLCS will move
east across the remainder of the CWA during the late evening hours
into the early morning hours of Sunday. The primary hazard will be
large hail, damaging winds and heavy rainfall.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CDT SAT MAY 16 2015
On Sunday the dry slot will work across the area with lower
dewpoints but daytime highs should still reach to around 80 given
mixing and expected sun. The cold front will finally move across
the area Sunday night and it should pass through dry however there
are some signals that precip may develop along it toward Mon
morning southeast of the area. For now will keep conds dry and
with CAA on Monday expect much cooler highs and lower humidities
as dewpoints fall into the 40s. Tues should also remain dry for
most of the day with rain expected to overspread the area Tues
night and last through Weds. Limited CAPE suggests only isolated
thunder but look for another widespread soaking rain out of this
system.
Perhaps a brief dry spell on Thursday before the next upper wave
approaches for late next week into next weekend. This system looks
very similar to this weekends so an active pattern will continue.
&&
.AVIATION...(For the 12Z TAFs through 12Z Sunday Morning)
Issued at 633 AM CDT SAT MAY 16 2015
Currently, TOP/FOE are varying between VFR/MVFR conditions. Have
kept prevailing VFR with a tempo MVFR group until 15Z to account for
this. At MHK, MVFR conditions are expected to prevail until 19Z
when ceilings will lift slightly. A line of TSRA moving slowly east
this morning and may reach terminals before weakening, so have
mentioned VCTS starting at 15Z at MHK and 17Z at FOE/TOP. The main
storms today should be in the afternoon, but timing in hard to
pinpoint so have included only VCTS at this time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN
ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER
OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID
SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF
CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK
MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH
VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT
RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU
MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE
SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH
PLAINS OF S DAKOTA TO NEB.
BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER
MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER
LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY
CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH
TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF
SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR
EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT
RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND
NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA
OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY.
MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF
AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY
OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR
TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF
CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT
LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER
100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR
MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH
EDGE OF H85-H7 MOISTURE TRANSPORT.
EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT
WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE
ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE
CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS
WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS
NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS
NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF
FOG...LOCALLY DENSE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 520 AM EDT SAT MAY 16 2015
SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM
THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE
SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50
KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5
INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL
ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF
INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS
INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400-
800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z
MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE
COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE
ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND
THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S
WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY 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 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO
SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY
BE DRY OVERNIGHT.
MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW
ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON
BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT
COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS
ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY
END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC
FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD
-SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER
TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH
EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO
GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W-
NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST.
MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO
VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS
BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY
LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR
CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN.
DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES
FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON
ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE
LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR
SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND
PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE
VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY
FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED
THRU FRI...BUT REMAIN BLO NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 728 AM EDT SAT MAY 16 2015
THICKER CLOUDS IN MID-LEVELS EARLY THIS MORNING HAVE PROHIBITED
WIDESPREAD FOG FROM FORMING. SHALLOW GROUND FOG EARLY AT KIWD BUT
OTHERWISE EXPECT MINIMAL FOG ISSUES REST OF THE DAY AND INTO
TONIGHT. SCT-BKN VFR CLOUDS WILL CONTINUE AT ALL THE TAF SITES INTO
TONIGHT. MIGHT SEE AN ISOLD SHRA OR TSRA LATE TONIGHT...BUT COVERAGE
AND PROBABILITY IS TOO LOW TO INCLUDE FOR THESE TAFS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW
PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING
E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF
THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY
MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE
LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL
USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND
TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE
EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION
WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20
KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250.
&&
$$
SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
546 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT SAT MAY 16 2015
VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST
THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT
CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION
THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE
ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE
CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS
NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE
MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME
SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH
THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT
MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS
SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE
RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE
AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL
LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD
OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE
ACROSS THE PLAINS AND INTO THE UPPER MIDWEST.
SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE
AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING
UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC
HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE
MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO
MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO
MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND
SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER
MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 406 AM CDT SAT MAY 16 2015
THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A
SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF
MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE
TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE
FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID
ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON.
THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW
PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS
MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE
AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER
LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE
COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM
WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES
APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON
SUNDAY AFTERNOON.
THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY
REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE
LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL
MN/WI THROUGH MONDAY.
BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS
AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL
CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO
ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH
FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE
60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY
NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS
PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 540 AM CDT SAT MAY 16 2015
HIGH CONFIDENCE THAT THE FIRST 6 HRS WILL BE THUNDERSTORM FREE
WITH THE EXCEPTION OF KRWF/KAXN WHERE ISOLD STORMS WILL BE
POSSIBLE BUT NOT ENOUGH TO WARRANT MORE THAN VCTS. MVFR CIGS WILL
SPREAD NORTHWARD ACROSS CENTRAL MN...WITH VFR CONDS ELSEWHERE THRU
15Z. AFT 18Z...CONFIDENCE IS MUCH LOWER ON SHRA/TSRA
COVERAGE...ESPECIALLY IN EASTERN MN/WC WI WHERE TSRA/SHRA MAY NOT
OCCUR UNTIL LATER THIS EVENING. HIGHER CONFIDENCE THAT WC/SW MN
WILL HAVE SHRA/TSRA WITH LOWER VSBYS/CIGS BY THIS EVENING. WINDS
WILL INCREASE FROM THE ESE/SE TODAY...WITH SOME GUSTS DURING THE
AFTN.
KMSP...
CONFIDENCE IS HIGH THAT NO TSRA/SHRA WILL OCCUR IN THE FIRST 6
HRS. CONFIDENCE DECREASES BY MID/LATE AFTN BUT CIGS SHOULD REMAIN
VFR. BEST CHC OF TSRA WILL OCCUR LATER THIS EVENING/OVERNIGHT.
WINDS WILL SHIFT TO THE SE AND INCREASE DURING THE MORNING.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS.
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...LS
AVIATION...JLT
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1018 AM CDT SAT MAY 16 2015
.UPDATE...WIDESPREAD CLOUD COVER PREVALENT OVER THE REGION THIS
MORNING SHOULD CONTINUE TO SLOW THE WARMING PROCESS. LATEST HRRR
APPEARS TO WARM THE REGION UP A LITTLE TOO FAST COMPARED TO LATEST
OBSERVATIONS. CURRENT FORECAST MAX TEMPS IN THE MID 80S STILL LOOKS
ATTAINABLE...JUST MAY TAKE A LITTLE LONGER TO ACHIEVE. AREA SOUNDINGS
SHOW DEEP MOISTURE IN PLACE THIS MORNING WITH PW VALUES RUNNING CLOSE
TO 1.75 INCHES. BEST LOW LEVEL MOISTURE REMAINS OVER THE
SOUTH...WHILE ON THE JAN SOUNDING THIS MORNING A DRY LAYER EXISTED
FROM 800-950 MB. LOOKING AT THE HRRR DATA...THIS DRY LAYER MAY SERVE
TO SLOW CONVECTIVE INITIATION UNTIL TEMPS CAN REACH INTO THE LOWER
80S. CURRENT FORECAST PACKAGE APPEARS ON TRACK./26/
&&
.AVIATION...UNDER SOUTHERLY MOIST FLOW EXPECT LINGERING IFR CEILINGS
IN THE SOUTHWEST TO LIFT UP TO MVFR BY 17Z. SHRA/TSRA
CHANCES(IFR/MVFR CONDITIONS) WILL BE LIKELY FOR THE WHOLE CWA FOR
THIS AFTERNOON AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE
WEST. THE DISTURBANCE WILL COMBINE WITH DAYTIME HEATING TO BRING GOOD
PCPN COVERAGE. SO INTERESTS SHOULD PLAN FOR TSRA AT ALL SITES FOR
THIS AFTERNOON. SHRA/TSRA WILL DIMINISH EARLY THIS EVNG WITH A FEW
SHRA LINGERING OVERNIGHT. LATEST GUIDANCE SUGGEST WIDESPREAD IFR
STRATUS WILL DEVELOP LATE TONIGHT INTO EARLY SUNDAY MRNG. /17/EC/
&&
.PREV DISCUSSION... /ISSUED 436 AM CDT SAT MAY 16 2015/
DISCUSSION...
TODAY THROUGH SUNDAY NIGHT...
FORECAST THINKING REMAINS THE SAME FOR TODAY AS A PERSISTENT TROUGH
TO RIDGE PATTERN OVER THE CENTRAL/EASTERN CONUS CONTINUES TO PROMOTE
VERY MOIST SOUTHERLY FLOW JUXTAPOSED BY DISTURBED SOUTHWESTERLY FLOW
ALOFT. LATEST HIGH-RES GUIDANCE CONTINUE TO SUGGEST WEATHER TRENDS
SIMILAR TO YESTERDAY. SHOWER/THUNDERSTORM ACTIVITY WILL REGENERATE
WITH DAYTIME HEATING AHEAD OF ANOTHER UPPER LEVEL SHORTWAVE TROUGH...
AND MAY BECOME FAIRLY WIDESPREAD IN THE AFTERNOON. 20-30KTS OF
LOW/MID LEVEL FLOW WILL SUPPORT SOME MULTI-CELL STORM ORGANIZATION
WITH STEEP LOW LEVEL LAPSE RATES AND FLOW SUPPORTIVE OF STRONG TO
PERHAPS EVEN A FEW SEVERE WIND GUSTS. THIS WILL ESPECIALLY BE THE
CASE WHERE STORMS ANCHOR ALONG OUTFLOW BOUNDARIES DURING PEAK
HEATING...AND WHERE THE BOUNDARIES ARE ORIENTED MORE WNW-ESE AND
ORTHOGONAL TO SSW LOW LEVEL SHEAR VECTORS. EXPECT ANY SEVERE WEATHER
OCCURRENCES TO BE VERY ISOLATED AND WILL KEEP THE MENTION OUT OF THE
HAZARDOUS WEATHER PRODUCTS FOR NOW.
GIVEN SUBSTANTIAL OUTFLOW MOTIONS AND HIGH COVERAGE OF PRECIPITATION
AGAIN TODAY...HAVE FOLLOWED HIGHER GUIDANCE POPS. CONVECTION WILL
DIMINISH EARLY IN THE EVENING AND DO NOT EXPECT IT TO PERSIST AS LONG
AS IT DID LAST NIGHT. SUNDAY WILL SEE SOMEWHAT OF A REPEAT OF THIS
PATTERN...BUT BETTER CONVECTIVE PRECIPITATION COVERAGE MAY HOLD OFF
UNTIL A STRONGER BOUNDARY APPROACHES LATE SUNDAY NIGHT IN NORTHWEST
PORTIONS OF THE ARKLAMISS. /EC/
MONDAY INTO SATURDAY...THE MED RANGE/LONG TERM LOOKS
TO REMAIN A BIT ON THE ACTIVE SIDE WRT PRECIP POTENTIAL. DEEP
MOISTURE (PWS 1.6-1.8 IN) WILL RESIDE OVER THE REGION THROUGH MUCH
OF THE PERIOD WITH THE PRESENCE OF A WEAK SFC BOUNDARY IN THE
VICINITY THROUGH THIS TIME AS WELL. ADDITIONALLY...GLOBAL MODELS
CONTINUE TO SHOW SEVERAL DISTURBANCES INTERACTING WITH THE MOISTURE
AND BOUNDARY TO HELP TRIGGER SHOWERS/STORMS. AT THIS TIME...THE MOST
PREVALENT WAVE LOOKS TO IMPACT THE CWA ON MON. IN RESPONSE TO
THIS...40-70% POPS ARE IN PLACE TO CAPTURE THE POTENTIAL. THE
OVERALL EVOLUTION OF ACTIVITY ON MON IS NOT CLEAR AS SOME OF THE
AREA COULD SEE PRECIP EARLY IN THE DAY FROM SOME LEFT OVER STORMS
MOVING OUT OF AR WITH OTHER SOLUTIONS SHOWING ACTIVITY WAITING UNTIL
THE AFTERNOON. THERE IS SOME POTENTIAL FOR STRONGER STORMS AS BETTER
MID LEVEL LAPSE RATES WILL BE IN PLACE ALONG WITH HIGHER DEEP LAYER
SHEAR. OVERALL...HOW THINGS EVOLVE AND TIMING WILL PLAY A KEY ROLE
AND WITH UNCERTAINTY IN THOSE...WILL NOT MENTION ANYTHING IN THE HWO
AT THIS TIME...BUT WILL KEEP A CLOSE EYE ON TRENDS.
LINGERING PRECIP CHANCES WILL EXIST THROUGH THE REMAINDER OF THE
WEEK WITH AT LEAST ONE OPPORTUNITY FOR A DECENT SHOT AT MORE PRECIP.
AT THIS TIME...THU INTO THU NGT MAY BE THAT PERIOD AS MOST MODELS
SHOW ANOTHER DECENT WAVE AND GOOD QPF SIGNAL.
AS FOR TEMPS...PERSISTENCE TYPE FORECAST IS IN ORDER AND THE BLENDED
GUID SEEMS TO BE ON TARGET. EXPECT TEMPS TO REMAIN JUST A BIT WARMER
THAN CLIMO READINGS WITH HIGHS ROUGHLY 85-90 AND LOWS 65-70.
SOUTHERN AREAS WILL LIKELY BE ON THE WARMER SIDE OF THOSE RANGES AS
THEY WILL BE FURTHER REMOVED FROM THE LINGERING SFC BOUNDARY. /CME/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 86 70 87 70 / 62 33 43 32
MERIDIAN 84 69 86 68 / 70 35 44 29
VICKSBURG 86 71 88 72 / 60 26 41 32
HATTIESBURG 85 70 87 70 / 70 45 41 20
NATCHEZ 85 72 87 72 / 59 29 40 23
GREENVILLE 85 71 86 71 / 64 34 59 50
GREENWOOD 85 70 87 70 / 69 34 49 49
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
936 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 923 AM CDT SAT MAY 16 2015
VERY MOIST BOUNDARY LAYER AFTER OVERNIGHT RAINS. ACROSS THE SOUTHWEST
A SOUTHEAST UPSLOPE FLOW HAS RESULTED IN AREAS OF FOG AND LOW
CLOUDS. WILL ADD THIS TO THE FOREST THROUGH NOON. ELEVATED
CONVECTION ONGOING OVER THE LOW LEVELS SOUTHWEST SO KEPT A SLIGHT
CHANCE OF THUNDERSTORMS THERE. HOWEVER...DROPPED THE MENTION OF
THUNDERSTORMS THIS MORNING NORTH AND EAST BASED ON LATEST HRRR
CAPE FORECAST WHICH BASICALLY HOLDS OF THE THREAT OF THUNDER TIL
THIS AFTERNOON.
UPDATE ISSUED AT 615 AM CDT SAT MAY 16 2015
AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM
DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH
CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE
NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN
RAPID CITY AND ABERDEEN SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUD COVER DAYBREAK TEMPERATURES MONDAY MORNING WILL
BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY
MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE
STRONG NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 923 AM CDT SAT MAY 16 2015
AT 930 AM CDT A SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHEAST
MONTANA WITH A WARM FRONT EXTENDED EAST ACROSS CENTRAL SOUTH
DAKOTA. MOIST FLOW OVER THE FRONT WILL MAINTAIN WIDESPREAD IFR
KISN- KDIK-KBIS WITH MVFR CONDITIONS KMOT-KJMS THROUGH NOON. LOW
LEVEL UPSLOPE FLOW ACROSS THE SOUTHWEST WILL RESULT IN VERY LOW
IFR CONDITIONS IN FOG AT KDIK THROUGH 17Z. CONDITIONS GENERALLY
BECOMING MVFR SATURDAY AFTERNOON. THUNDERSTORMS WILL BECOME MORE
NUMEROUS LATE SATURDAY AFTERNOON AND EVENING EAST OF KBIS-KMOT
LINE.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE 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...WAA
SHORT TERM...JV
LONG TERM...JPM
AVIATION...WAA
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
623 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 615 AM CDT SAT MAY 16 2015
AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM
DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH
CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE
NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN
RAPID CITY AND ABERDEEN SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUDCOVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE
WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY
THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG
NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 615 AM CDT SAT MAY 16 2015
THE MAIN CONCERN IS THE SHOWER / THUNDERSTORM CHANCES AND THE
ASSOCIATED MVFR CEILINGS / VISIBILITIES. EXPECT INCREASING
CHANCES FOR SHOWERS THROUGH THE DAY...WITH INCREASING CHANCES FOR
THUNDERSTORMS ESPECIALLY CENTRAL AND EASTERN NORTH DAKOTA TAF
SITES. AFTER 03Z ON THE 17TH THUNDER CHANCES WILL DECREASE AS
WIDESPREAD RAIN MOVES IN WITH MVFR CONDITIONS.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE 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...JPM
SHORT TERM...JV
LONG TERM...JPM
AVIATION...JV/JPM
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1000 AM EDT SAT MAY 16 2015
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL AFFECT THE REGION
THIS WEEKEND. A COLD FRONT WILL APPROACH ON MONDAY...MOVING
THROUGH BY EARLY TUESDAY. HIGH PRESSURE BUILDS IN DURING THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRECIPITATION HAS SLOWLY BEGUN TO INCREASE IN COVERAGE OVER THE
PAST FEW HOURS...AND THIS TREND IS GENERALLY EXPECTED TO CONTINUE
THROUGH EARLY TO MID AFTERNOON. AN ANALYSIS OF LOW-LEVEL WINDS
INDICATES PERSISTENT SOUTHWESTERLY FLOW...BRINGING A CONTINUED
TRANSPORT OF MOISTURE DIRECTLY INTO THE OHIO VALLEY. THERE IS
CONVERGENCE AHEAD OF THIS MOISTURE ADVECTION...AND AS WEAK
INSTABILITY BUILDS...THE COVERAGE AND INTENSITY SHOULD INCREASE AS
WELL. POPS HAVE BEEN REFINED SLIGHTLY BUT REMAIN AT THE HIGH
CHANCE TO LIKELY LEVELS ACROSS THE FORECAST AREA (PRIMARILY AROUND
18Z-21Z). IF THE HRRR VERIFIES...PRECIPITATION MAY END UP EVEN
MORE WIDESPREAD...AND FUTURE UPDATES MAY NEED TO INCREASE THE
PRECIPITATION CHANCES EVEN FURTHER.
THE 12Z KILN SOUNDING IS VERY MOIST (PWAT OF 1.42 INCHES) WITH
POOR LAPSE RATES THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE.
THIS WILL LIMIT INSTABILITY TODAY...WITH A NARROW PROFILE OF CAPE
THAT MAY GET TO AROUND 1000 J/KG AT MOST. WITH WEAK SHEAR...STORM
ORGANIZATION SHOULD NOT BE MUCH TO SPEAK OF...AND THUS THE THREAT
FOR STRONG STORMS APPEARS LOW.
TEMPERATURES WERE ADJUSTED JUST SLIGHTLY DOWNWARD...WITH
CONFIDENCE IN CLOUDS AND PRECIPITATION (AND A MOIST BOUNDARY
LAYER) LIMITING HEATING POTENTIAL.
PREVIOUS DISCUSSION >
A FEW SHOWERS CONTINUE TO AFFECT WESTERN/CENTRAL OHIO AT 07Z. THIS
ACTIVITY WILL CONTINUE TO MOVE NORTH-NORTHEAST OVER THE NEXT FEW
HOURS...LIKELY DISSIPATING BY SUNRISE.
RIDGE AXIS HAS SHIFTED A LITTLE EAST OF THE OHIO
VALLEY EARLY THIS MORNING...RESULTING IN A BROAD SOUTHWEST FLOW
ALOFT. WEAK VORT MAXES EMBEDDED WITHIN THIS FLOW WILL CONTINUE TO
SUPPORT PERIODS OF CONVECTIVE ACTIVITY THROUGH THE DAY. IT LOOKS
LIKE THE NEXT ROUND OF CONVECTION WILL LIKELY OCCUR IN NORTHERN
KENTUCKY/SOUTHWEST OHIO BY 10-11Z...MOVING NORTHEAST DURING THE
MORNING. THEN AN ADDITIONAL UPTICK IN CONVECTION WILL LIKELY OCCUR
FOR THE MIDDAY/AFTERNOON GIVEN INCREASING PRECIPITABLE WATER
VALUES /POSSIBLY AROUND 1.7 INCHES BY AFTERNOON/...AFTERNOON
INSTABILITY AND THE LIKELIHOOD OF ANOTHER VORT MAX PROMOTING LIFT.
WENT WITH HIGH CHANCE TO LOW END LIKELY POPS ACROSS THE CWA DURING
THIS TIME.
GIVEN RELATIVE WEAK INSTABILITY /MOST GUIDANCE SUGGESTING CAPE
LESS THAN 1000 J/KG/ AND SHEAR...SEVERE WEATHER IS NOT EXPECTED.
HOWEVER CAN/T RULE OUT A LOCALLY STRONG STORM WITH GUSTY WINDS AND
ALSO GIVEN HIGHER MOISTURE CONTENT LOCALLY HEAVY DOWNPOURS MAY
RESULT.
USED A BLEND OF BIAS CORRECTED MET/MAV FOR HIGH TEMPERATURES
TODAY...FAVORING UPPER 70S/AROUND 80 ACROSS MUCH OF THE CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
WHILE COVERAGE OF CONVECTION FROM THE AFTERNOON/EARLY EVENING
SHOULD WANE OVERNIGHT...WILL CONTINUE WITH LOW CHANCE POPS ACROSS
THE CWA AS ATMOSPHERE WILL REMAIN WARM/MOIST AND ANY VORT MAX MAY
KEEP SOME CONVECTION GOING INTO THE NIGHT.
SIMILAR SITUATION IS EXPECTED ON SUNDAY...WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGHOUT THE DAY BUT THE HIGHEST COVERAGE TO
FAVOR THE AFTERNOON. A COLD FRONT IS THEN EXPECTED TO APPROACH ON
MONDAY. WIND FIELDS MAY BE A LITTLE BETTER AND COULD PROMOTE SOME
DEGREE OF ORGANIZATION TO THUNDERSTORMS. CONFIDENCE IS LOW HOWEVER
AND WILL LEAVE MENTION OF STRONG/SEVERE STORMS OUT OF THE HWO
ATTM. MONDAY WILL FEATURE ONE MORE WARM/MUGGY DAY BEFORE CHANGES
OCCUR BEHIND THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL THEN MOVE THROUGH THE AREA LATE MONDAY NIGHT AND
TUESDAY MORNING WITH DRIER AND COOLER AIR MOVING IN BEHIND.
MODELS HAVE SLOWED THE FRONT DOWN A BIT AND GIVEN CURRENT
FORECASTED UPPER LEVEL FLOW THIS MAKES SENSE. THE UPPER LEVEL LOW
JUST NORTH OF WISCONSIN MONDAY WASHES OUT WITH A SECONDARY
SHORTWAVE MOVING SOUTH TUESDAY INTO WEDNESDAY. FORECASTED 850
TEMPERATURES FOR NEXT WEEK (5 - 10 DEGREES C) ALSO DON`T LOOK AS
COOL AS THEY WERE OVER THE LAST COUPLE OF DAYS. HAVE TRENDED HIGH
TEMPERATURES UP TOWARDS 70 A BIT TO ACCOUNT FOR THIS. BELOW NORMAL
TEMPERATURES WILL THEN CONTINUE THROUGH THE END OF THE NEXT WORK
WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
UNSETTLED WEATHER OVER THE OHIO VALLEY WILL NECESSITATE SOME TYPE
OF SHOWER AND THUNDERSTORM MENTION AT ALL TAF SITES FOR THE
FORESEEABLE FUTURE. SOUTHERLY FLOW WILL CONTINUE TO PUMP INCREASED
MOISTURE TO THE REGION AND MID LEVEL SHORTWAVES WILL TRAVERSE A H5
RIDGE THAT IS IN PLACE OVER THE EASTERN U.S. THIS ESTABLISHED RIDGE
WILL KEEP MOST STORMS IN CHECK AND THE CONSENSUS IN THE NEXT DAY
OR TWO IS FOR GARDEN VARIETY THUNDERSTORMS OF A SCATTERED NATURE
BECOMING MORE NUMEROUS DURING THE DAY.
SHOWERS AND OCCASIONAL THUNDERSTORMS WILL DROP VSBYS TO MVFR
VALUES BUT MOST CIGS SHOULD REMAIN VFR FOR THE NEXT 24-30 HOURS.
SATURATED CONDITIONS THROUGH THE LOWER ATMOSPHERE WILL BE FOUND AT
VARIOUS LEVELS THAT WILL BE AS DIFFICULT TO PINPOINT AS THE
LOCATIONS OF THE STORMS. CONTINUE TO LEAVE OUT MVFR CIGS FROM
CU/SC WHILE DROPPING THEM SLIGHTLY IN PRECIP WHICH IS MORE HEAVILY
FOCUSED IN TEMPO GROUPS.
WINDS WILL BE SSW AT 10KT OR LESS.
OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY THROUGH MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BPP
NEAR TERM...HATZOS/BPP
SHORT TERM...BPP
LONG TERM...HAINES
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
941 AM 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 TONIGHT/...
FROM 00Z TO 12Z SOUNDINGS...SHOW PRECIPITABLE WATER AT BNA INCREASED
FROM 1.3 TO 1.7 INCHES...AT ILN FROM 1.1 TO 1.4 INCHES. PIT DID NOT
INCREASE MUCH IN PAST 12 HRS.
VERY WEAK 500 MB VORT MAX ON RAP LIFTS FROM HTS VCNTY AT 13Z THROUGH
NORTH CENTRAL WV 17-19Z...BUT OVERALL 500 HEIGHTS ARE NOT FALLING.
AS A RESULT...INCREASED POPS A BIT QUICKER IN WESTERN WEST VIRGINIA
THIS MORNING INTO EARLY AFTERNOON.
ANOTHER 500 MB DISTURBANCE MAY LIFT OUT OF TENNESSEE RIVER VALLEY
TODAY...REACHING US TONIGHT. WE MAINTAIN AT LEAST CHANCE POPS
THROUGH THE NIGHT. WITH PLENTY OF LAYERED CLOUDS OVERNIGHT...DID NOT
HIT FOG HARD OVERNIGHT FOR THE PUBLIC...BUT COULD EASILY BE 3 TO 5
MILES.
DID LOWER MAX TEMP A FEW DEGREES IN SOUTHEAST OHIO AND NRN WV
TODAY...FIGURING ON THE AFFECTS OF THIS FIRST DISTURBANCE.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
MODELS SHOW H500 RIDGE AXIS MOVING OVER WV SUNDAY. THE CMC/NAM/GFS
MODELS SHOW FEW VORTICITY MAX ALONG THIS RIDGE FLOW FROM 12Z SUNDAY
THROUGH 00Z MONDAY. MODELS ALSO SHOW AN INCREASE IN PRECIPITABLE
WATER REACHING 1.9 INCHES BY 18Z SUNDAY. H850 FLOW BECOMES STEADY
FROM THE SOUTHWEST PUMPING JUICIER AND WARMER AIR MASS TO THE
AREA. THUS...UNSETTLED ATMOSPHERE...WITH SFC CAPE FROM 1800-2000
J/KG SUGGEST GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS MAINLY DURING
THE AFTERNOON HOURS.
BY MONDAY...A COLD FRONT CROSSES THE OH VALLEY...KEEPING OUR AREA
UNDER A WARM SECTOR. WITH BETTER SUPPORT FROM THIS COLD
FRONT...SUSPECT CONVECTION AHEAD OF THE FRONT WILL LIGHT UP TO
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER
AROUND 1.7 AHEAD OF THE FRONT SUGGEST SOME STORMS COULD PRODUCE
HEAVY DOWNPOURS MONDAY. KEPT LIKELY POPS WITH THIS ENVIRONMENT. THE
COLD FRONT SHOULD REACH SOUTHEAST OH BY 12Z TUESDAY...CROSSING EAST
ENDING PCPN BY 00Z WEDNESDAY.
EXPECT ABOVE NORMAL TEMPERATURES SUNDAY AND MONDAY BECOMING NEAR
NORMAL TUESDAY. USED A BLEND OF PREVIOUS NUMBERS AND THE BIAS
CORRECTED CONSENSUS ALL GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL PUSH THROUGH MONDAY NIGHT. ECMWF HAS PERSISTENTLY
BEEN PUSHING IT THROUGH CLEANLY...WHILE THE GFS HAS AT TIMES SHOWED
SIGNS OF IT GETTING HUNG UP...BUT RECENTLY HAS BEEN SHOWING THE
CLEAN SWEET AS WELL. SO MINIMAL CHANGES TO PREVIOUS FORECAST...WITH
DRIER AND COOLER AIR FILTERING IN MID WEEK. THINGS MAY GET A LITTLE
MESSIER AT THE END OF THE WEEK AND INTO THE WEEKEND AS MOISTURE
BEGINS TO RETURN.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
06Z SATURDAY THRU 06Z SUNDAY...
ISOLATED STORMS HAVE PUSHED EAST OF THE AREA AT THIS TIME. VFR
CONDITIONS PREVAILED IN MOST LOCATIONS...WITH SOME VALLEY
LOCATIONS SEEING MVFR AND EVEN IFR VSBYS.
ADDITIONAL SHOWERS AND STORMS...WHICH WERE APPROACHING FROM THE
WEST...SHOULD SPREAD EAST ACROSS THE REGION...AND INCREASE IN
AREAL COVERAGE. CURRENT THINKING IS THE GREATEST CONCENTRATION OF
STORMS SHOULD OCCUR BETWEEN 17Z AND 23Z. EXPECT BRIEF MVFR AND
IFR CONDITIONS IN VICINITY OF STORMS. GUSTY WINDS ARE ALSO
POSSIBLE WITH THE STRONGER STORMS.
THE STORMS SHOULD BEGIN TO DECREASE IN INTENSITY AND AREAL COVERAGE
AFTER 03Z. WHILE CONDITIONS SHOULD BE VFR IN MOST LOCATIONS...MVFR
AND IFR CONDITIONS WILL BE POSSIBLE ALONG RIVER VALLEYS AND IN
AREAS THAT RECEIVED RAINFALL TODAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM
ALTERNATE SCENARIOS: STORMS WITH ISOLATED CONDITIONS MAY NOT BE AS
NUMEROUS AS EXPECTED.
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.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY M H M H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H M H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z SUNDAY...
BRIEF IFR IN THUNDERSTORMS POSSIBLE THROUGH TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/KTB/ARJ
NEAR TERM...KTB
SHORT TERM...ARJ
LONG TERM...MZ
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1202 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A STALLED FRONTAL ZONE WILL BE THE FOCUS FOR PERIODS OF UNSETTLED
WEATHER THIS WEEKEND...AS SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED EACH DAY. THE WEEKEND WILL NOT BE A WASHOUT...AS THERE
WILL BE DRY TIMES WITH PERIODS OF SUNSHINE AS WELL. A RELATIVELY
STRONG COLD FRONT WILL PUSH ACROSS THE AREA MONDAY NIGHT AND
TUESDAY...USHERING IN ANOTHER COOL...DRY AIRMASS FOR LATE TUESDAY
THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
1150 AM UPDATE...
CONVECTIONWANED FOR A BIT...BUT STARTING UP AGAIN. HRRR HAS A
GREAT HANDLE ON CURRENT CROP OF STORMS...INCL THE STUFF NEAR
KHLG/KPIT AND KBFD. HEATING WILL POP CONVECTION IN MANY MORE
LOCATIONS AS THE SHORT WAVE DRIVING THE CURRENT ACTIVITY RUNS INTO
THE CURRENTLY SUNNY AREA. WILL KNOCK TEMPS DOWN A BIT IN THE NW
AND UP SLIGHTLY FOR THE NEXT FEW HRS IN THE SE. THEN WIDESPREAD
CONVECTION SHOULD COOL IT OFF. SEVERE THREAT STILL LURKING AROUND
THE CORNER...WITH BEST GUIDANCE ALSO INDICATING SOME STRONGER WINDS
ALOFT. WOULD NOT BE SURPRISED TO SEE A BOX SOMETIME THIS
AFTN...ESP IF THE CLUSTER OVER KPIT CONTINUES TO INCREASE IN
COVG/INTENSITY...WHICH SEEMS MORE THAN LIKELY.
PREV...
SCATTERED SHOWERS CONTINUE TO TRACK ACROSS THE NORTHERN HALF OF
CENTRAL PA...NOW ACCOMPANIED BY ISOLATED THUNDER AS STATIC
STABILITY HAS DECREASED OVERNIGHT WITH THE PASSING OF A SHORTWAVE
TROF FROM THE EASTERN GLAKS CROSSING THE FINGERLAKES REGION.
MARGINALLY UNSTABLE AIR MASS WITH MODERATE MOISTURE (PW ~1.5") AND
BOUNDARY LAYER CONVERGENCE INVOF STALLED WARM FRONT WILL FOCUS
SHOWER AND THUNDERSTORM CHANCES THROUGHOUT THE DAY. SHOWERS WILL
BE MOST PROBABLE AND NUMEROUS ACROSS THE NORTHERN HALF OF CENTRAL
PA...BUT EVEN THE SOUTH CAN SEE AN ISOLATED SHOWER OR THUNDERSTORM
AT JUST ABOUT ANY TIME...BUT MOST LIKELY DURING MAX DIURNAL
HEATING THIS AFTERNOON. N CENTRAL PA IS IN MARGINAL SPC OUTLOOK
FOR THIS AFTERNOON...SO WILL BE WATCHFUL FOR PULSE STORMS WHICH
COULD PRODUCE HEAVY DOWNPOURS...GUSTY WINDS AND SMALL HAIL.
HIGHS WILL RANGE FROM THE MID 70S NORTH WHERE CLOUDS WILL BE
THICKEST AND SHOWERS AT THEIR MOST FREQUENT...TO THE LOWER TO
MIDDLE 80S SOUTHEAST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM SUNDAY/...
AFOREMENTIONED QUASISTATIONARY BOUNDARY WILL BE DRAPED ACROSS PA
TONIGHT INTO EARLY SUNDAY BEFORE SETTLING SOUTHWARD SUNDAY
AFTERNOON AS DRIER AND COOLER AIR WORKS SOUTHWARD FROM HIGH
PRESSURE OVER NORTHERN NEW ENGLAND AND NEWFOUNDLAND.
WHILE THE TREND WILL BE FOR DECREASING SHOWER ACTIVITY...A SHOWER
OR TSTM CAN/T BE RULED OUT AT PRACTICALLY ANY TIME DURING THIS
PERIOD. KEPT POPS IN THE LOWER TO MID CHC RANGE FROM TONIGHT
THROUGH SUNDAY MORNING...WITH DECREASING POPS SUNDAY AFTERNOON.
LOWS TONIGHT WILL RANGE FROM THE UPPER 50S NORTH TO THE MID 60S
SOUTHEAST. HIGHS WILL ONCE AGAIN RANGE FROM THE MID 70S NORTH TO
AROUND 80 OVER THE LOWER SUSQ.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
LEAD SHORTWAVE ENERGY CLIMBING THE WESTERN-SIDE OF ANOMALOUS
500MB RIDGE OVER THE EASTERN US...ALONG WITH ABOVE NORMAL PWATS
AND DIURNAL INSTABILITY WILL HELP PROMOTE SCATTERED CONVECTION ON
SUNDAY...ESPECIALLY ALONG/SOUTH OF THE QUASI-STNRY/WARM FRONTAL
BOUNDARY PIVOTING OVER THE AREA. USED A BLEND FOR POPS/QPF WHICH
FAVORED THE LAUREL HIGHLANDS AND SOUTH-CENTRAL MTNS ON DAY 3.
GIVEN LACK OF FORCING AND LOSS OF DAYTIME HEATING...CUT BACK POPS
TO THE MID-CHC RANGE SUNDAY NIGHT /40 PERCENT WEST TO 30 PERCENT
EAST/.
THE VIGOROUS/DEEP CLOSED LOW EJECTING OUT OF THE SOUTHWESTERN
U.S. SHOULD REACH THE NORTHERN PLAINS BY 00Z MON...WHERE THE
MODELS SHOW IT SLOWING DOWN AND EVENTUALLY BECOMING ABSORBED INTO
AN UPPER TROUGH CROSSING HUDSON BAY. THIS HAS APPEARED TO SLOW
THE EASTWARD PROGRESSION OF ITS TRAILING COLD FRONT BY 12HRS OR
SO...NOW PROGGED TO CROSS THE AREA DURING THE DAYTIME ON TUESDAY
(PREVIOUSLY MONDAY NIGHT/AM TUESDAY). THIS SLOWER TREND WAS EVIDENT
IN THE GUIDANCE AND HAVE ADJUSTED TEMPS AND POPS ACCORDINGLY. THE
PARENT SHORTWAVE WILL LOSE MUCH OF ITS AMPLITUDE AS IT TRACKS
THROUGH THE UPPER GREAT LAKES AND FOR NOW DOES NOT APPEAR TO POSE
A SIGNIFICANT SVR WX RISK FOR EARLY NEXT WEEK.
IN THE WAKE OF THE COLD FRONTAL PASSAGE...A RESPECTABLE ANTICYCLONE
WILL EXTEND SEWD FROM THE UPPER MIDWEST WITH COOLER AND NOTICEABLY
DRIER AIR FILTERING INTO THE REGION FOR THE MID TO LATE WEEK
PERIOD. THIS PATTERN SHOULD SUPPRESS THE PCPN RISK TO THE SOUTH OF
CENTRAL PA WITH GENERALLY FAIR WEATHER AND SEASONABLY COOL TO
MODERATING TEMPERATURES PREVAILING AT DAYS 6-8. ALSO OF NOTE IS
THE RISK FOR PATCHY FROST ON MAY 21ST/THURSDAY MORNING MAINLY OVER
THE NORTH-CENTRAL ZONES WHERE ECENS/GFS ENSEMBLE MOS GUIDANCE IS
SHOWING MID 30S AT BFD...JUST IN TIME FOR THE START OF THE GROWING
SEASON.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
NOON...
CONVECTION MOVING BACK IN FROM THE WEST. WILL ATTEMPT TO TIME IT
INTO JST/AOO/IPT. WINDS MAY BE ERRATIC/GUSTY IN
THUNDERSTORMS...BUT TOO TIGHT OF A WINDOW TO TRY TO MAKE MORE THAN
A TEMPO MENTION OF THAT.
PREV...
THE LAST REMAINING CLUSTER OF SHOWERS AND THUNDERSTORMS HAVE MOVED
PAST IPT AND ARE CONTINUING TO PROGRESS EASTWARD. EXPECT A LULL IN
THE PRECIPITATION THROUGH THE MORNING. HOWEVER AS THE WARM FRONT
LAGS...AND THE TEMPERATURES RISE...PRECIPITATION WILL BEGIN TO
BUBBLE AND MOVE THROUGH CENTRAL PA...AFFECTING MOST TAF SITES AT
TIMES THIS AFTERNOON AND EARLY EVENING. HOWEVER VFR CIGS AND VSBYS
WILL BE DOMINATE WITH MVFR TO IFR IN HEAVIER SHOWERS AND
THUNDERSTORMS. THE STRONGEST STORMS SHOULD BE ALONG THE SOUTHERN
CORRIDOR OF PENNSYLVANIA...AFFECTING JST...AOO...MDT AND LNS.
SHOWERS COULD CONTINUE OVERNIGHT...WITH MVFR CIGS POSSIBLE AFTER
03Z. BFD COULD SEE IFR BY THIS TIME DUE TO CALMING WINDS AND
COPIOUS AMOUNTS OF LOW LEVEL MOISTURE PRESENT. THIS ALSO REMAINS
POSSIBLE AT UNV. WINDS SHOULD PERSIST AT JST WHICH SHOULD ONLY
ALLOW MVFR...THOUGH IFR REMAINS POSSIBLE...THOUGH LOWER
PROBABILITY.
OUTLOOK...
SUN-TUE MORNING...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS WITH LOCAL REDUCTIONS TO MVFR AND BRIEF IFR
POSSIBLE.
WED-THU...MAINLY VFR WITHIN A COOLER/DRIER AIRMASS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR/LAMBERT
LONG TERM...STEINBUGL
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
653 AM EDT SAT MAY 16 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND. INCREASING MOISTURE OVER THE WESTERN EDGE OF THE HIGH WILL
BRING PRECIPITATION CHANCES MAINLY TO THE MOUNTAINS TODAY AND
SUNDAY. A COLD FRONT APPROACHES MONDAY...POSING BETTER CHANCES FOR
PRECIPITATION FOR THE WHOLE AREA THROUGH TUESDAY. SLIGHTLY COOLER
AND DRIER HIGH PRESSURE WILL RETURN WEDNESDAY IN THE WAKE OF THE
FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 655 AM EDT...THE EARLY MORNING HOURS HAVE TRENDED LESS CLOUDY
OVER THE HEART OF THE FORECAST AREA...WHICH HAS PERMITTED SOME
PATCHY DENSE FOG TO FORM OVER THE NC FOOTHILLS...MAINLY NEAR
MORGANTON. A LOWER CLOUD DECK DID MANAGE TO DEVELOP ALONG INTERSTATE
77...BUT THIS SHOULD BE MUCH SHORTER LIVED THAN THE LOW CLOUDS
OBSERVED YESTERDAY MORNING GIVEN THE SMALLER SPATIAL EXTENT OF THE
CLOUDS AND EXPECTED MORNING HEATING.
OTHERWISE...A BROAD UPPER LEVEL RIDGE AXIS WILL REMAIN IN PLACE OVER
THE EASTERN THIRD OF THE NATION TODAY THROUGH TONIGHT. THE BEST LOW
TO MID LEVEL MOISTURE RETURN AROUND THE RIDGE WILL CONTINUE TO
AFFECT THE SPINE OF THE SRN APPALACHIANS THROUGH THE PERIOD. WITH
LOW LEVEL WINDS VEERED MORE S TO SW TODAY...TRIGGERING OF SHRA AND
LATER DAY TSRA MAY BE EVEN MORE CONFINED TO THE MTNS...ESPECIALLY
NEAR THE TN BORDER...THAN OBSERVED ON FRI. THERE WILL BE MUCH LESS
IN THE WAY OF EARLY DAY LOW CLOUDS...BUT STILL EXPECT OCNL MID AND
HIGH LEVEL CLOUDS TOPPING THE ERN RIDGE...ALONG WITH A DEVELOPING
CUMULUS FIELD FROM THE RECOVERING SFC DEWPOINTS AND HEATING. ALL
TOLD...ENOUGH INSOLATION IS EXPECTED TO PERMIT TEMPS TO WARM INTO
THE UPPER 70S TO NEAR 80 IN THE LOWER MTN VALLEYS AND 80 TO 85 EAST
OF THE MTNS. SBCAPE VALUES ALONG THE SPINE OF THE MTNS MAY REACH
1000 TO 1500 J/KG...WITH LESSER INSTABILITY EAST DUE TO MORE
NEGATIVE BUOYANCY AREAS IN THE MODEL PROFILES AND BETTER MID LEVEL
CAPPING. STEERING FLOW WILL ONCE AGAIN BE LIGHT...WITH LIGHTNING AND
LOCALLY HEAVY RAINFALL IN THE MTNS THE PRIMARY THREATS WITH ANY
THUNDERSTORMS.
LINGERING EVENING ISOLD TO SCT SHRA/TSRA IN THE MTNS WILL DIMINISH
QUICKLY TONIGHT AND LIKELY DISSIPATE EVERYWHERE BUT THE FAR SW MTNS
OVERNIGHT. MIN TEMPS SHOULD GAIN ANOTHER DEGREE OR SO AS THE AIRMASS
CONTINUES TO MODIFY UNDER SRLY FLOW. IF THE HIGH CLOUDS THIN
SUFFICIENTLY...MTN VALLEY FOG WILL BECOME MORE LIKELY LATE TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 AM SAT...SHARP UPPER RIDGE WILL BE SITUATED OVER THE ERN
SEABOARD SUNDAY AS A WELL DEVELOPED LOW PRESSURE SYSTEM MOVES INTO
THE UPPER MISSISSIPPI VALLEY. SW FLOW OFF THE GULF WILL CONTINUE THRU
SUN AFTN...AND CONVECTION IS EXPECTED TO INITIATE OVER THE MTNS IN
TYPICAL FASHION. HOWEVER FAVORABLE PROFILES ARE SEEN ON NAM PROGS
INTO THE FOOTHILLS AS WELL. THE RIDGE PUSHES EWD IN ADVANCE OF THE
LOW SUNDAY NIGHT...ALLOWING SLIGHTLY LOWER HEIGHTS ALOFT MONDAY. THIS
WILL MAKE FOR MORE UNSTABLE CONDITIONS WHICH SPREAD ACRS THE CWFA.
COLD FRONT ASSOC WITH THE LOW CONTINUES TO APPROACH MON NIGHT BUT
APPRECIABLE COLD ADVECTION DOES NOT ARRIVE UNTIL NEAR DAYBREAK TUE.
WHILE MOIST PROFILES MAY STILL BE PRESENT MON NIGHT...CONVECTION
GENERALLY LOOKS TO WANE WITH THE LOSS OF HEATING. THREATS WILL
PRIMARILY BE HEAVY RAIN EACH DAY...WITH PWAT VALUES PROGGED TO BE
ABOVE THE 75TH PERCENTILE AND WEAK FLOW IMPLYING SLOW MOVING STORMS.
THE UPSIDE OF THE MOIST PROFILES IS THAT DOWNBURST THREAT WILL BE
FAIRLY LOW. TEMPS TREND UPWARD FROM SUN TO MON BUT WITH AFTN MAXES
SEVERAL DEGREES ABOVE CLIMO BOTH DAYS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 250 AM SAT...AS SFC LOW MOVES ACRS QUEBEC TUESDAY...COLD FRONT
WILL MOVE OFF THE MID-ATLANTIC COAST. ASSOCIATED CONVERGENCE ZONE
WILL LIKELY ENHANCE CONVECTIVE COVERAGE OVER OUR PIEDMONT REGION
WHERE SIMILAR INSTABILITY WILL BE IN PLAY COMPARED TO THAT OF MONDAY.
HOWEVER THE MTNS WILL SEE LESS UNSTABLE CONDITIONS ON ACCOUNT OF THE
INCOMING CONTINENTAL AIRMASS. BY WED THIS WILL HAVE SPREAD ACROSS THE
WHOLE CWFA. DRY AND SETTLED WEATHER MAY BE SHORT LIVED AS THE NRN
STREAM CONTINUES TO FEATURE A TROUGH TO OUR NORTH LATE IN THE
WEEK...AROUND WHICH DISTURBANCES OR MINOR SHORTWAVES WILL PASS ATOP A
WEAK STATIONARY BOUNDARY ON THE SRN FRINGE OF THE HIGH. THIS WILL
BRING SMALL PRECIP CHANCES BACK THU...GFS AND EC SHOWING SOME
DIFFERENCES /AND RUN-TO-RUN VARIATION/ IN EXACTLY WHERE THAT BOUNDARY
SETS UP. INSTABILITY WILL REMAIN ON ITS WARM SIDE SUPPORTING POPS
EVEN IF ANY UPGLIDE OVER IT IS TOO WEAK. DIURNAL INSTABILITY LOOKS TO
RETURN BY FRIDAY ANYWAY AS POPS AGAIN EXHIBIT A CLIMATOLOGICAL FOCUS
ON THE MTNS. CONFIDENCE IS LOW ON THE TEMP FCST...WITH A COOLING
TREND AND RETURN TO NEAR-NORMAL READINGS LIKELY IF THE BOUNDARY
SETTLES PAST THE AREA...BUT ABOVE NORMAL MAX TEMPS CONTINUING IF IT
STALLS TO THE NORTH.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...AN MVFR DECK HAS FORMED OVERHEAD...BUT IT SHOULD BE FAIRLY
SHORT LIVED SINCE IT HAS LIMITED SPATIAL EXTENT AND RAP PROFILES
DISSIPATE THE LOW LEVEL MOISTURE QUICKLY THROUGH 14Z.
OTHERWISE...EXPECT MAINLY SCT TO BKN HIGHER LEVEL VFR CLOUDS
SPILLING OVER THE RIDGE THROUGH THE PERIOD...WITH CONVECTIVE CUMULUS
FILLING IN AT 5 TO 6 KFT DURING THE PEAK HEATING HOURS. SURFACE
WINDS WILL REMAIN SOLIDLY S TO SW AT SPEEDS LESS THAN 10 KT. MODEL
PROFILES ALL STILL EXHIBIT A WEAK SUBSIDENCE CAP WHICH WILL LIMIT
ANY PIEDMONT CONVECTION.
ELSEWHERE...KAVL WILL SEE A CHANCE OF A SHOWER OR LATE DAY
THUNDERSTORM...BUT WITH SLIGHTLY MORE CAPPING IN PROFILES
DIMINISHING THE CHANCES FARTHER EAST OVER THE FOOTHILLS. EXPECT OCNL
VFR CIGS THROUGHOUT...WITH MID AND HIGH LEVEL CIGS TOPPING THE UPPER
RIDGE AXIS EARLY AND LATE...AND PERHAPS CONVECTIVE CUMULUS CIGS AT 5
TO 6 KFT WITH PEAK HEATING. SRLY WINDS WILL REMAIN 10 KT OR LESS
THROUGH THE PERIOD. BRIEF FOG IS POSSIBLE MAINLY NEAR KHKY AROUND
DAYBREAK THIS MORNING...AND AT KAVL LATE TONIGHT.
OUTLOOK...A PLUME OF MOISTURE FROM THE GULF OF MEXICO WILL INCREASE
ACROSS THE REGION THROUGH EARLY NEXT WEEK. RESTRICTIONS FROM STRATUS
AND/OR FOG COULD DEVELOP DURING THE PRE/DAWN HOURS EACH MORNING
ACROSS AREAS THAT RECEIVED RAIN THE PREVIOUS AFTERNOON OR EVENING.
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 94% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 94% 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...UPDATED
NWS ABERDEEN SD
656 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 647 AM CDT SAT MAY 16 2015
AVIATION DISCUSSION UPDATED BELOW FOR 12Z TAFS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 647 AM CDT SAT MAY 16 2015
QUITE A VARIATION OF CONDITIONS THROUGH THE TAF FORECAST PERIOD.
THIS MORNING...A MIX OF CIGS ACROSS THE REGION RANGING FROM AROUND
500 FT TO LOW END VFR CONDITIONS. ALSO SEEING SHRA AFFECTING KABR
AND KATY BUT WILL BE ENDING BY 13Z. EXPECTING REDEVELOPMENT OF
SHOWER AND STORM ACTIVITY BY AROUND 18Z AND PERSISTING THROUGH THE
AFTERNOON ACROSS MUCH OF THE FORECAST AREA. HEAVIER STORMS MAY
DROP CIGS INTO MVFR AND VSBY INTO IFR. SEVERE STORMS ARE POSSIBLE
AS WELL AND COULD AFFECT TERMINALS WITH GUSTY SFC WINDS AND HAIL.
LATE T0NIGHT...ANOTHER BATCH OF RAINFALL IS EXPECTED TO MOVE
NORTHWARD INTO THE REGION.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
649 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 638 AM CDT SAT MAY 16 2015
BROAD AREA OF MVFR AND IFR CONDITIONS ACROSS THE FORECAST AREA
THIS MORNING IN ADDITION TO SCATTERED TSRA TRACKING NORTHEAST
THROUGH THE REGION. EXPECT THIS ACTIVITY TO CONTINUE TO WEAKEN AND
DIMINISH THROUGH 15Z. MODELS SUGGEST THAT SOME IMPROVEMENT TO
CEILINGS FROM SOUTH TO NORTH THROUGH MIDDAY. ADDITIONAL SHOWER AND
THUNDERSTORMS DEVELOPMENT IS EXPECTED IN THE AFTERNOON...BECOMING
MORE WIDESPREAD BY EVENING. TIMING IS A BIT DIFFICULT AT THIS
POINT...BUT HAVE ADDED TSRA MENTION AND LOWER CEILINGS TO TAF
SITES THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1049 AM CDT SAT MAY 16 2015
.UPDATE...
AN AREA OF SHOWERS CONTINUE TO MOVE NORTH OVER PORTIONS OF WEST
TENNESSEE...NORTHEAST ARKANSAS...AND THE MISSOURI BOOTHEEL. THIS
AREA SHOULD MOVE INTO KENTUCKY AND MISSOURI BETWEEN 12-1 PM.
MEANWHILE...DRY CONDITIONS ARE CURRENTLY OCCURRING OVER NORTH
MISSISSIPPI. THE LATEST HRRR SHOWS ADDITIONAL DEVELOPMENT
OCCURRING ACROSS SOUTHERN MISSISSIPPI THAT WILL MOVE INTO NORTH
MISSISSIPPI AROUND 2 PM. THE CONVECTION WILL EVENTUALLY SPREAD
INTO THE REST OF THE MIDSOUTH BETWEEN 3-5 PM. FORECAST LOOKS
GOOD...NO UPDATES ARE EXPECTED.
KRM
&&
.DISCUSSION... /ISSUED 430 AM CDT SAT MAY 16 2015/
A WET DAY IS IN STORE FOR THE MIDSOUTH TODAY...FINALLY SEEMS MORE
LIKE MAY ACROSS THE MIDSOUTH THAN WHAT WE HAVE EXPERIENCED THROUGH
MUCH OF THE FIRST HALF OF THE MONTH. AREAS OF RAIN AND A FEW
THUNDERSTORMS WERE ALREADY OCCURRING ACROSS THE MIDSOUTH EARLY THIS
MORNING. THE WET PATTERN WILL CONTINUE INTO MONDAY AND WILL NEED TO
MONITOR FOR THE POSSIBILITY OF FLOODING / FLASH FLOODING AS RAINFALL
AMOUNTS INCREASE OVER TIME THROUGH THE WEEKEND INTO MONDAY.
A LARGE UPPER LEVEL LOW WAS LOCATED OVER THE WESTERN UNITED
STATES WITH AN UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST. A
SOUTHERLY WIND FLOW BETWEEN THESE TWO SYSTEMS WAS PUSHING ABUNDANT
MOISTURE INTO THE MIDSOUTH FROM THE GULF OF MEXICO. AN UPPER LEVEL
SHORT WAVE WAS LOCATED OVER EAST TX AND WILL MOVE NORTHEASTWARD
THROUGH THE MIDSOUTH TODAY. OCCASIONAL SHOWERS AND SCATTERED
THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY. PRECIPITABLE
WATER VALUES WILL BE BETWEEN 1.8 AND 2.0 INCHES WITH SURFACE DEW
POINTS IN THE MIDDLE 60S TO NEAR 70 DEGREES. AS A RESULT...LOCALLY
HEAVY RAINFALL MAY RESULT IN FLOODING IN SOME LOCATIONS TODAY...BUT
NOT CONFIDENT ENOUGH THAT WILL BE WIDESPREAD ENOUGH FOR A FLASH FLOOD
WATCH ATTM. DID MENTION THE THREAT OF LOCALLY HEAVY RAINFALL
AND FLOODING IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. INSTABILITY
LOOKS TO BE A LITTLE LESS THAN YESTERDAY WITH MORE WIDESPREAD RAIN
AND CLOUDS.
FOR TONIGHT...AN UPPER LEVEL TROUGH MOVES INTO THE CENTRAL PLAINS
WITH AN ASSOCIATED COLD FRONT STRETCHING FROM KS INTO TX. ORGANIZED
CONVECTION IS EXPECTED TO DEVELOP AHEAD OF THIS FRONT THROUGH THE
PLAINS PERHAPS APPROACHING NORTHEAST ARKANSAS LATE TONIGHT...ALTHOUGH
INSTABILITY DECREASING BY THAT TIME. WEAK UPPER LEVEL DISTURBANCES
EMBEDDED IN SOUTHWEST FLOW ALOFT WILL CONTINUE THE THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT ACROSS THE MIDSOUTH.
SUNDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR
WITH LOCALLY HEAVY RAINFALL A CONTINUING THREAT. THE UPPER LEVEL
TROUGH WILL PUSH TO THE NORTHEAST THROUGH THE CENTRAL PLAINS WITH
THE ASSOCIATED COLD FRONT REMAINING TO OUR WEST AND NORTH. THE
GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE TO OUR NORTH. 0-6
KM BULK SHEAR VALUES ARE ONLY MARGINAL FOR ORGANIZED SHEAR WEATHER
NEAR EXTREME NORTHEAST ARKANSAS AND THE MO BOOTHEEL. HOWEVER...
WIND FIELDS WILL BE STRONGER ACROSS THE MIDSOUTH SUNDAY AS THE UPPER
LEVEL TROUGH MOVES TO OUR NORTH. THIS WILL ALLOW WARMER SURFACE
TEMPERATURES TO PUSH INTO THE MIDSOUTH CAUSING GREATER INSTABILITY
AND THE POSSIBILITY A FEW STRONG TO SEVERE THUNDERSTORMS. IF ANY
SEVERE THUNDERSTORMS DO DEVELOP...DAMAGING WIND AND LARGE HAIL
WOULD BE THE GREATEST SEVERE WEATHER THREATS.
A COLD FRONT WILL SAG INTO THE MIDSOUTH FROM THE NORTH MONDAY AS THE
UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST WEAKENS SOME WITH
LOWERING UPPER LEVEL HEIGHTS ACROSS THE MIDSOUTH. WILL ONCE AGAIN
NEED TO MONITOR FOR HEAVY RAINFALL AND FLOODING / FLASH FLOODING.
THE COLD FRONT WILL GRADUALLY PUSH THROUGH THE MIDSOUTH MONDAY NIGHT
AND TUESDAY WITH DECREASING CHANCES FOR RAIN FROM THE NORTH.
TEMPERATURES WILL BE A LITTLE COOLER WITH PASSAGE OF THE COLD FRONT.
FOR THE REMAINDER OF THE WORK WEEK...THE ECMWF AND GFS ARE NOT IN
VERY GOOD AGREEMENT ON HOW FAR SOUTH THE COLD FRONT PUSHES AND HOW
QUICKLY IT PUSHES BACK NORTH. NEVERTHELESS...THE MODELS DO INDICATE
A CHANCE OF SHOWERS...PERHAPS THUNDERSTORMS...WILL MOVE BACK INTO
THE REGION FROM THE WEST. THE ECMWF IS FASTER BRINGING THE THREAT
OF SHOWERS AND THUNDERSTORMS BACK INTO THE REGION AS QUICKLY AS
WEDNESDAY.
JCL
&&
.AVIATION...
12Z TAFS
AN AREA OF SHOWERS WITH ISOLATED LIGHTNING STRIKES IS CURRENTLY
BEING OBSERVED ACROSS MEM...JBR AND MKL. THIS WILL CONTINUE TO
LIFT NORTH THIS MORNING WITH LOW CIGS ACCOMPANYING IT. CIGS DOWN
TO MVFR AND OCCASIONALLY IFR AT TIMES ARE EXPECTED. EXPECT
REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS DURING THE LATE MORNING
HOURS ACROSS ALL TERMINALS SO VCTS COVERS THIS POTENTIAL UNTIL
TIMING CAN BE NAILED DOWN. IT APPEARS THAT A LULL IN THE SHOWER
ACTIVITY WILL OCCUR LATE SATURDAY NIGHT INTO SUNDAY MORNING
ALTHOUGH WINDS WILL STAY ABOVE 10KTS THROUGH THE NIGHT FROM THE
SOUTH.
TVT
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1028 AM CDT SAT MAY 16 2015
.UPDATE...
A QUICK LOOK AT THE ENVIRONMENT THIS MORNING FROM THE 12Z FORT
WORTH SOUNDING DOES SHOW SUBSIDENCE WAS RELATIVELY STRONGER THAN
EXPECTED LATE YESTERDAY BEHIND THE DEPARTING SHORTWAVE. HOWEVER...
LAPSE RATES ABOVE THE EML REMAIN STEEP AND MOISTURE RICH ENOUGH
THAT SOME HIT AND MISS SHOWERS AND STORMS ARE POSSIBLE OVER THE
REGION THIS AFTERNOON. TODAY. HIGH RES MODELS OUTSIDE OF THE
RAPID REFRESH/HRRR HAVE DELAYED ACTIVITY INTO THE WESTERN
COUNTIES UNTIL AFTER 00Z/7 PM. THE HRRR IS AN HOUR OR TWO SOONER
FOR CONVECTIVE POTENTIAL. WE WILL BE ISSUING A SPECIAL 18Z
SOUNDING EARLY THIS AFTERNOON TO RE-EVALUATE THE ENVIRONMENTAL
CHANGES.
WE HAVE TRIMMED BACK THE ARRIVAL FOR POSSIBLE DISCRETE SEVERE
STORMS TO VERY LATE THIS AFTERNOON FOR MAINLY YOUNG/JACK/AND
MONTAGUE COUNTIES WHERE AN ENHANCED RISK FOR SEVERE WEATHER
REMAINS. THE MAIN UNCERTAINTY WILL BE THE DELAYED TIMING OF THE
STRONGER MID-LEVEL HEIGHT FALLS/LARGE SCALE ASCENT AND THE MODEST
EML CURRENTLY IN PLACE. THE DRYLINE REMAINS WELL TO THE WEST
ACROSS EASTERN NEW MEXICO AND HAS A WAYS TO GO BEFORE REACHING OUR
WESTERN COUNTIES LATE TODAY. REGARDLESS...BY THIS EVENING SEVERE
STORMS WILL BE POSSIBLE ACROSS AREAS MAINLY NORTH OF I-20 AND WEST
OF I-35/35W WITH ALL MODES OF SEVERE WEATHER POSSIBLE.
HAVE MADE TIMING ADJUSTMENTS FOR THE DAYTIME PERIOD WITH ALL THESE
ITEMS IN MIND. AS THE SYSTEM BECOMES LINEAR TO THE LARGE SCALE
FORCING LATE THIS EVENING AND OVERNIGHT...IT WILL BE FED BY A
STRENGTHENING LLJ AND ASSOCIATED WAA. THE SEVERE THREAT WILL
BECOME MORE LOCALIZED WHILE THE HYDROLOGICAL THREAT RAMPS WITH
POSSIBLE TRAINING STORMS WITH VERY HEAVY RAINFALL WITH PWAT
VALUES WELL ABOVE NORMAL. CURRENT FLOOD PROBLEMS WILL ONLY BE
EXACERBATED WITH FLASH FLOODING POSSIBLE DURING THE OVERNIGHT
HOURS INTO SUNDAY MORNING. A FLASH FLOOD REMAINS IN EFFECT FOR
MOST OF THE AREA THROUGH TONIGHT...THEN FOR OUR CENTRAL TEXAS
COUNTIES ON SUNDAY.
05/
&&
.AVIATION...
/ISSUED 656 AM CDT SAT MAY 16 2015/
MVFR CEILINGS WILL PREVAIL AT ALL TAF SITES THROUGH THE MORNING
WITH CEILINGS LIFTING AND SCATTERING THIS AFTERNOON. VFR
CONDITIONS ARE EXPECTED THIS EVENING EXCEPT IN AND NEAR
THUNDERSTORMS.
LIFT WILL BE ON THE INCREASE THROUGH THE AFTERNOON AS A POWERFUL
UPPER LOW MOVES TOWARD THE NORTHERN HIGH PLAINS. WE EXPECT
THUNDERSTORMS TO DEVELOP WEST OF THE TAF SITES LATE THIS
AFTERNOON. THESE STORMS SHOULD ORGANIZE INTO A LINE AND MOVE EAST
DURING THE EVENING. THE BEST WINDOW OF TIME FOR THE STORMS TO MOVE
ACROSS THE METROPLEX TAF SITES WILL BE BETWEEN 05Z AND 09Z AND
SLIGHTLY LATER IN WACO.
A SOUTH WIND WILL PREVAIL THROUGH TONIGHT AT SPEEDS BETWEEN 11
AND 16 KNOTS WITH SOME HIGHER GUSTS DURING THE DAY. WINDS COULD
BECOME STRONG AND GUSTY AS THE LINE OF THUNDERSTORMS MOVES THROUGH
TONIGHT.
79
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT SAT MAY 16 2015/
WV SAT LOOP SHOWS A BROAD UPPER LOW OVER THE INTERMOUNTAIN REGION
WITH A SHORT WAVE TROUGH OVER SOUTHERN ARIZONA AND ANOTHER OVER
WESTERN NEVADA. THE SOUTHERN RADAR MOSAIC THIS MORNING SHOWS
SIGNIFICANT CONVECTION ALONG A DRYLINE/PACIFIC COLD FRONT OVER THE
TEXAS HIGH PLAINS AND PANHANDLE REGION WHICH WILL CONTINUE TO
ADVANCE TOWARD NORTH/CENTRAL TEXAS TODAY. AS THE CONVECTION ENTERS
THE FAR WESTERN COUNTIES LATE THIS AFTERNOON...THERE COULD BE SOME
MARGINALLY SEVERE TO SEVERE THUNDERSTORMS DUE TO HIGH CAPE AND
0-3KM SHEAR OF 35-40 KNOTS. ANY DISCRETE SUPERCELL WILL NEED TO BE
WATCHED FOR STRONG ROTATING UPDRAFTS THAT COULD PRODUCE A
TORNADO.
COME THIS EVENING...THE STORMS SHOULD BECOME MORE LINEAR AND MORE
PARALLEL TO THE UPPER FLOW WHICH WILL INCREASE THE POTENTIAL FOR
ECHO TRAINING...HEAVY RAINFALL AND FLASH FLOODING DURING THE
OVERNIGHT HOURS. THE HEAVY RAIN POTENTIAL WILL CONTINUE THROUGH
SUNDAY MORNING OVER THE SOUTHEAST ONE HALF OF THE CWA...THUS WE
HAVE DECIDED TO MOVE THE WATCH SOUTHEASTWARD AND EXTEND IT THROUGH
SUNDAY AFTERNOON AS SOME AREAS MAY RECEIVE AN ADDITIONAL 1/2 TO 1
INCH DURING THE DAY. THE WATCH MAY NEED TO BE EXTENDED FURTHER
INTO SUNDAY NIGHT IF THE QPF OF THE GFS AND ECMWF PANS OUT. WE WILL
TACKLE PROBLEM ON THE NEXT COUPLE OF SHIFTS.
SINCE THE AIR MASS DOES NOT CHANGE MUCH ON MONDAY...WE WILL
CONTINUE TO CARRY A CHANCE OF CONVECTION DURING THE DAY WITH A
LESSER CHANCE MONDAY NIGHT. A COLD FRONT WILL MOVE SOUTH OF THE
RED RIVER LATE MONDAY NIGHT AND THEN STALL ALONG THE I-20 CORRIDOR
ON TUESDAY. THE FRONT WILL MOVE BACK NORTH TUESDAY NIGHT ONLY TO
COME BACK SOUTH LATER IN THE WEEK AS OUR NEXT UPPER SYSTEM MOVES
THROUGH THE DESERT SOUTHWEST AND INTO THE CENTRAL ROCKIES. THE
SHORT WAVE ENERGY ASSOCIATED WITH THIS SYSTEM SHOULD PASS FARTHER
TO THE NORTHWEST OF NORTH TEXAS...THUS WE/LL KEEP POPS MOSTLY IN
THE CHANCE CATEGORY TUESDAY THROUGH WEDNESDAY. HOWEVER...THERE IS
A FAIRLY STRONG CONVECTIVE SIGNAL BEING ADVERTISED WEDNESDAY NIGHT
PER THE GFS/ECMWF MODELS AND HAVE ADDED LIKELY POPS TO THE RED
RIVER REGION FOR THE WEDNESDAY NIGHT PERIOD.
THURSDAY THROUGH FRIDAY...WE/LL KEEP CHANCE POPS ACROSS THE CWA
AS ANOTHER UPPER TROUGH DROPS DOWN THE WEST COAST AND INTO THE
SOUTHWEST BY LATE NEXT WEEK. THIS WILL RESULT IN SLIGHT UPPER
RIDGING ON THURSDAY FOLLOWED BY SOUTHWESTERLY FLOW ALOFT AND A
COUPLE OF SHORTWAVE RIPPLES ON FRIDAY.
THERE WILL BE LITTLE CHANGE IN MAX/MIN TEMPERATURES THROUGH THIS
FORECAST...HIGHS MOSTLY 80-85 AND LOWS MOSTLY IN THE MID-UPPER
60S. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 82 69 84 70 83 / 30 80 40 40 40
WACO, TX 83 71 83 70 83 / 30 70 70 50 50
PARIS, TX 81 69 82 69 81 / 40 80 60 50 40
DENTON, TX 80 68 84 68 84 / 30 80 30 40 30
MCKINNEY, TX 81 69 83 68 83 / 30 80 40 50 40
DALLAS, TX 82 69 85 70 84 / 30 80 50 50 40
TERRELL, TX 83 71 84 69 82 / 30 70 60 60 40
CORSICANA, TX 83 72 83 70 81 / 30 50 70 50 50
TEMPLE, TX 84 72 83 70 83 / 30 50 60 40 50
MINERAL WELLS, TX 81 66 84 67 84 / 40 80 30 20 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH SUNDAY
MORNING FOR TXZ091>095-100>107-115>121-129>134-141.
FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR TXZ147-148-158-160>162-174-175.
FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH SUNDAY
AFTERNOON FOR TXZ122-123-135-142>146-156-157-159.
&&
$$
79/05
Area Forecast Discussion
National Weather Service Spokane WA
821 AM PDT SAT MAY 16 2015
.SYNOPSIS...
Scattered showers with embedded thunderstorms will be possible
for the next several days. The best chance of widespread showers
and isolated thunderstorms will be late this afternoon and
Sunday, especially over north Idaho and Northeast Washington.
Seasonably mild conditions will continue through the next week
with showers possible over the higher terrain.
&&
.DISCUSSION...
A minor update has been sent to extend the band of wrap around
rain slightly to the west to include the Lewiston area. Radar
trends as well as the HRRR suggest this area of rain will shift
south and east of the Lewiston area and Camas Prairie by late
morning so this is not expected to last much longer. For this
afternoon the HRRR shows increasing shower and isolated
thunderstorm development over NE Washington Mountains and Idaho
Panhandle, and then drifting southwestward into the Spokane area,
Okanogan Highlands, and Palouse by late this afternoon or early
evening as a low level boundary helps initiate convection.
Elevated dew points currently in the mid 40s to lower 50s around
Spokane, Deer Park, and Sandpoint along with an eroding mid level
cloud deck should allow for some morning and afternoon sun which
will allow for increased surface heating to help inititate
convection. It is this area that the 06z GFS has the best
instability with uncapped CAPE values as high as 500-1000 J/KG. Brief
heavy rain...small hail...and wind gusts to around 30 mph are the
main threats with these storms. JW
&&
.AVIATION...
12z TAFS: An axis of deeper moisture currently extends across the ID
Panhandle which is bringing -shra KPUW/KLWS and MVFR cigs vcnty KCOE.
After 20z...aftn heating will incr convective showers and some thunderstorm
activity. A front will slide in the NE btwn 23-04z and we should see
sct -shra and isold -tsra along the front. The front will be slow to clear
the ID/WA border with pcpn finally shifting west of KGEG-KCOE aft 08z.
Main uncertainty this aftn will be thunder coverage and duration of impacts
at eastern terminals. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 72 49 69 49 72 49 / 40 60 10 20 10 10
Coeur d`Alene 68 48 69 45 72 47 / 70 40 10 20 10 10
Pullman 65 46 68 44 71 45 / 40 60 30 30 20 30
Lewiston 70 50 73 51 76 53 / 80 50 30 30 30 30
Colville 77 51 72 48 74 50 / 40 60 20 20 10 10
Sandpoint 69 46 69 40 70 41 / 70 40 10 10 10 10
Kellogg 65 45 68 43 70 44 / 70 60 10 10 20 20
Moses Lake 78 51 71 50 77 51 / 10 30 40 40 10 10
Wenatchee 78 51 71 54 78 55 / 10 40 50 40 10 10
Omak 79 51 71 50 76 49 / 10 70 50 50 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS EUREKA CA
335 PM PDT SAT MAY 16 2015
.SYNOPSIS...A SERIES OF UPPER LOWS WILL BRING SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS TO MAINLY THE INTERIOR EACH AFTERNOON
THROUGH MID WEEK. OTHERWISE DRY WEATHER CONDITIONS WITH BELOW
NORMAL TEMPERATURES WILL CONTINUE TO PREVAIL THROUGH NEXT WEEK.
&&
.DISCUSSION...AN UPPER LOW WILL APPROACH THE NORTH COAST TONIGHT
INTO SUNDAY MORNING. PROFILES ARE NOT LOOKING ALL THAT IMPRESSIVE
FOR STORMS THIS EVENING WITH LIFTED INDICES NEAR -1C...CAPE
AROUND 300J/KG AND EQUILIBRIUM LEVELS NEAR 22KFT. WILL GO AHEAD
AND TOSS ISOLATED SHOWERS AND STORMS INTO THE FORECAST OVER THE
YOLLA BOLLYS AND TRINITY MOUNTAINS FOR EARLY THIS EVENING IN THE
OUTSIDE CHANCE WE DO GET A FEW STRIKES. THIS WILL ALSO BLEND WITH
NEIGHBORING CWA`S AND SPC`S GENERAL TSTM OUTLOOK.
HIGH RESOLUTION MODELS SHOW THE ACTIVITY DYING DOWN THIS EVENING
AFTER LOSS OF PEAK HEATING...THEN SPIKING UP AGAIN LATE TONIGHT
INTO SUNDAY MORNING. CONFIDENCE IS NOT HIGH THIS WILL ACTUALLY
OCCUR DUE TO THE RELATIVELY LOW CAPE AND WEAK FORCING FROM THE
APPROACHING LOW PRESSURE SYSTEM ALOFT. THE POSSIBILITY DOES EXIST
WE MAY SEE STORMS REDEVELOP IN THE EARLY MORNING HOURS...SO WILL
GO AHEAD AND ADD THEM TO THE FORECAST. IF IT DOES NOT HAPPEN...OH
WELL.
SUNDAY IS STILL LOOKING BETTER FOR INTERIOR CONVECTION AS THE
UPPER LOW APPROACHES CAPE MENDO. THE AREA OF GREATEST INSTABILITY
AND PRECIP SHOULD SHIFT INTO WESTERN PORTIONS OF HUMBOLDT AND DEL
NORTE COUNTIES WITH PERHAPS SOME ACTIVITY IN THE NE PORTION OF
MENDOCINO COUNTY. CONFIDENCE THUNDERSTORMS WILL ADVECT OUT TO THE
COAST IS NOT HIGH DUE TO WEAK SSE FLOW ALOFT TO PROPEL THE
STORMS. ANY STORMS THAT DO MANAGE TO SPROUT UP WITH HEATING WILL
PROBABLY QUICKLY COLLAPSE. THE GFS AND ECMWF HAVE BEEN TOO BROAD
BRUSH WITH THE PRECIP SO WILL CONTINUE TO USE THE NAM12 AS THE
PRIMARY GUIDANCE. THE HIRES-NMM AND HRRR HAVE BEEN MODELING THE
CONVECTION FAIRLY GOOD AS WELL. THUS THE BROAD BRUSH GFS AND ECMWF
FIELDS HAVE BEEN SCALED BACK. SHOWER AND ISOLATED STORM CHANCES
WILL LIKELY PERSIST ON MONDAY AS THE UPPER LOW MEANDERS SOUTHWARD
OVER CENTRAL CALIFORNIA. A BROAD LOW PRESSURE SYSTEM ALOFT WILL
REMAIN OVER THE REGION ON TUE. CONVECTIVE PARAMETERS WERE NOT
LOOKING AS FAVORABLE FOR STORMS ON TUE. IT IS STILL 3 DAYS OUT AND
A LOT WILL CHANGE BETWEEN NOW AND THEN. SO WILL NOT MAKE TOO MANY
CHANGES HERE.
.LONG-TERM...WED THROUGH SAT...A BROAD AND COMPLEX LOW PRESSURE
SYSTEM ALOFT WILL CONTINUE TO BRING A THREAT OF SHOWERS AND
PERHAPS ISOLATED T-STORMS TO MAINLY THE INTERIOR THROUGH THU.
MORE STABLE CONDITIONS MAY DEVELOP FRI INTO SAT AS A RIDGE ALOFT
BUILDS CLOSER TO THE COAST. THE MODELS WERE NOT EXACTLY IN GREAT
AGREEMENT HERE. THE GFS BUILDS A FLAT RIDGE OVER THE WEST COAST WHILE
THE ECMWF HAS ANOTHER UPPER LOW DIVING SOUTHWARD. THE GEM WAS IN
BETWEEN WITH BROAD CYCLONICALLY CURVED NORTH FLOW OVER THE AREA.
CONSIDERING THE PERSISTENT LARGE SCALE TROUGH PATTERN AND THE
DISCONGRUITY IN THE MODEL DATA...WILL MAINTAIN A SLIGHT CHANCE OF
SHOWERS IN THE INTERIOR FRI THROUGH SAT.
&&
.AVIATION...VFR CEILING HAVE PERSISTED ALONG THE COASTAL AIR
TERMINALS MOST OF THE DAY...ALTHOUGH CLOUDS MAY CONTINUE TO NUDGE
SLIGHTLY WEST INTO ACV AND CEC THROUGH THE AFTERNOON. CEILINGS
SHOULD BUILD BACK INTO COASTAL AREAS DURING THE LATE AFTERNOON
/EVENING...THEN REMAIN MVFR THOUGH THE LATE MORNING HOURS ON SUNDAY.
INLAND CONDITIONS SHOULD REMAIN VFR THROUGH THE NEXT TAF CYCLE.
&&
.MARINE...GENERALLY LIGHT NORTHERLIES AND SMALL SHORT PERIOD SEAS
ARE BEING OBSERVED ACROSS ALL WATERS. THESE CONDITIONS WILL REMAIN
GENERALLY STEADY STATE THROUGH THE MIDDLE OF THE WEEK...AS WINDS ARE
EXPECTED TO REMAIN IN THE MODERATE TO FRESH RANGE. A REINFORCING MID
PERIOD WESTERLY SWELL WILL BUILD INTO THE WATERS OVER THE WEEKEND
BUT IS NOT EXPECTED TO BE PARTICULARLY LARGE...WHILE A SMALL
SOUTHERLY SWELL WILL CONTINUE TO MOVE THROUGH AS WELL.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS NEW YORK NY
347 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/...
WARM FRONT LOCATED NEAR THE NYC METRO AS OF 19Z WILL CONTINUE TO
SLOWLY LIFT NE THROUGH THE AREA THIS EVENING. IT IS POSSIBLE THE
WARM FRONT DOES NOT COMPLETELY CLEAR FAR EASTERN ZONES UNTIL TONIGHT.
DESTABILIZATION UNDERWAY WEST OF THE HUDSON RIVER WITH ENOUGH
BREAKS IN THE CLOUDS FOR SUNSHINE TO WARM TEMPERATURES INTO THE
UPPER 70S AND LOWER 80S...WITH DEW POINTS IN THE UPPER 50S AND
LOWER 60S.
LATEST HRRR AS WELL AS ITS PREVIOUS SEVERAL RUNS HAVE A BAND OF
CONVECTION MOVING INTO THE LOWER HUDSON VALLEY AROUND 21-22Z. THIS
HAS SUPPORT FROM THE 12Z NAM AND 15Z RAP AS WELL AS THE 12Z SPC
WRF. SURFACE BASED INSTABILITY DIFFERS SOMEWHAT AMONG THE MODEL
GUIDANCE...BUT HAVE ENOUGH CONFIDENCE THAT 800 TO 1200 J/KG OF
SURFACE BASED CAPE WILL BE AVAILABLE ACROSS THE FAR NW INTERIOR
FOR CONVECTION TO TAP INTO LATE THIS AFTERNOON AS IT MOVES INTO
THE AREA. MODERATELY STRONG WESTERLY LOW-MID LEVEL FLOW SUPPORTS
UNIDIRECTIONAL SHEAR AROUND 30 KT. A MARGINAL RISK OF SEVERE
WEATHER PER SPC CONTINUES WEST OF THE HUDSON RIVER WHERE GREATEST
SURFACE BASED INSTABILITY WILL RESIDE. THE THREAT IS FOR A STORM
OR TWO TO CONTAIN DAMAGING WIND GUSTS.
THE BAND OF CONVECTION WILL CONTINUE MOVING EAST THIS EVENING...
REACHING THE NYC METRO AROUND 00Z. WITH MARITIME INFLUENCE ALONG AND
EAST IF THE HUDSON RIVER...INSTABILITY WILL BE ELEVATED WITH
LITTLE TO NO CHANCE FOR ANY SEVERE CONVECTION. CONVECTION SHOULD
ELEVATED AND BEGIN TO WEAK AS IT MOVES OVER LONG ISLAND AND
SOUTHERN CT. HOWEVER...MULTIPLE SHORT WAVES ALOFT ROUNDING THE TOP
OF THE RIDGE MAY HELP TO SUSTAIN THE CONVECTION AS IT WORKS ITS
WAY EAST. CURRENT FORECAST PACKAGE INDICATED LIKELY SHOWERS/STORMS
WEST OF THE HUDSON AND LIKELY SHOWERS WITH A CHANCE OF
THUNDERSTORMS EAST OF THE HUDSON.
HIGH PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY
DOWNPOURS IN ANY STORM. MINOR URBAN FLOODING IS A POSSIBILITY.
CONVECTION DISSIPATES BY MIDNIGHT WITH SHOWERS LINGERING THROUGH
DAYBREAK SUNDAY. 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 /20Z SATURDAY THROUGH THURSDAY/...
A WARM FRONT LIFTS THROUGH THE REGION THIS AFTERNOON. A SURFACE
TROUGH THEN 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...EXCEPT FOR MVFR
HAZE AT KHPN AND MVFR CEILINGS AT KGON.
FOR TERMINALS W OF HUDSON HAVE GONE WITH PREVAILING SHRA/TEMPO
TSRA LATE THIS AFTERNOON/EARLY THIS EVENING. FOR TERMINALS E OF
THE HUDSON HAVE GONE WITH VCTS WITH TEMPO SHRA THIS EVENING.
WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT
WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. FOR NOW HAVE
CONTINUED WITH LOW END MVFR FORECAST (3SM/1000FT)...HOWEVER
CANNOT RULE OUT IFR...OR EVEN VFR FOR THAT MATTER.
WINDS MAINLY LIGHT AND VARIABLE OUTSIDE OF SEABREEZES THIS
AFTERNOON...AND SOUND BREEZE KLGA AND SEABREEZE KJFK/KBDR/KGON
LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON.
.OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY...
.SUNDAY AFTERNOON/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 ON THE OCEAN WATERS THIS AFTERNOON AND EVENING
DIMINISH TONIGHT. 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.
&&
$$
SYNOPSIS...DS/24
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...24
AVIATION...MALOIT
MARINE...DS/24
HYDROLOGY...DS/24
AREA FORECAST DISCUSSION
NWS NEW YORK NY
139 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT WILL BE SLOW TO PUSH NORTH OF THE AREA THIS AFTERNOON...
WHILE A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST THIS
EVENING AND STALLS OUT ACROSS THE AREA ON SUNDAY. A BACKDOOR COLD
FRONT MOVES THROUGH LATE SUNDAY NIGHT AS HIGH PRESSURE BUILDS
SOUTH ALONG THE NEW ENGLAND COAST. THE FRONT WILL THEN RETURN
NORTH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD FRONT
LATE TUESDAY. HIGH PRESSURE WILL THEN BUILD IN FOR THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WARM FRONT LOCATED NEAR THE NYC METRO AS OF 17Z WILL CONTINUE TO
SLOWLY LIFT NE OF THE AREA THROUGH THIS AFTERNOON. ENOUGH BREAKS
IN THE CLOUDS SHOWING UP ON VISIBLE SATELLITE IMAGERY FOR HIGHER
CONFIDENCE IN ACHIEVING HIGH TEMPERATURE FORECAST OF HIGHS IN THE
LOWER 80S INLAND AND INVOF NYC METRO...AND MAINLY IN THE 70S
ELSEWHERE.
INSTABILITY WILL BEGIN TO INCREASE THIS AFTERNOON WEST OF THE
HUDSON RIVER AHEAD OF MID LEVEL IMPULSE AND WEAK SHORTWAVE. A LEE
TROUGH ALSO DEVELOPS ACROSS E PA AND APPROACHES LATE THIS
AFTERNOON. LATEST 15Z HRRR GUIDANCE AS WELL AS ITS PREVIOUS
SEVERAL RUNS HAVE A BAND OF CONVECTION MOVING INTO THE LOWER
HUDSON VALLEY AROUND 21-22Z. THIS HAS SUPPORT FROM THE 12Z NAM AND
15Z RAP AS WELL AS THE 00Z SPC WRF. SURFACE BASED INSTABILITY
DIFFERS SOMEWHAT AMONG THE MODEL GUIDANCE...BUT HAVE ENOUGH
CONFIDENCE THAT 800 TO 1200 J/KG OF SURFACE BASED CAPE WILL BE
AVAILABLE ACROSS THE FAR NW INTERIOR FOR CONVECTION TO TAP INTO
LATE THIS AFTERNOON AS IT MOVES INTO THE AREA. MODERATELY STRONG
WESTERLY LOW-MID LEVEL FLOW SUPPORTS UNIDIRECTIONAL SHEAR AROUND
30 KT.
THE STREAK OF 23 CONSECUTIVE DAYS...APRIL 23 TO MAY 15...OF NO
MEASURABLE PRECIPITATION AT CENTRAL PARK HAS ENDED TODAY WITH 0.09
INCHES OF RAIN OCCURRING THIS MORNING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
A BAND OF CONVECTION WILL BE MOVING INTO LOCATIONS WEST OF THE
HUDSON RIVER THIS EVENING...REACHING THE NYC METRO AROUND 00Z. A
MARGINAL RISK OF SEVERE WEATHER PER SPC CONTINUES WEST OF THE
HUDSON RIVER WHERE GREATEST SURFACE BASED INSTABILITY WILL RESIDE.
THE THREAT IS FOR A STORM OR TWO TO CONTAIN DAMAGING WIND GUSTS. WITH
MARITIME INFLUENCE FURTHER EAST...INSTABILITY WILL BE ELEVATED
WITH LOWER CHANCE FOR ANY SEVERE CONVECTION. CONVECTION LIKELY
BECOMES ELEVATED AND WEAKER AS IT MOVES EAST OF THE HUDSON.
HOWEVER...MULTIPLE SHORT WAVES ALOFT ROUNDING THE TOP OF THE RIDGE
MAY HELP TO SUSTAIN THE COMPLEX AS IT WORKS TOWARD THE COAST. HIGH
PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY
DOWNPOURS. MINOR URBAN FLOODING IS A POSSIBILITY.
CONVECTION IS FORECAST TO DISSIPATE BY DAYBREAK SUN WITH A
QUIETER DAY EXPECTED WITH THE UPPER RIDGE BUILDING DIRECTLY
OVERHEAD. SHOULD SEE SOME PARTIAL CLEARING WITH HIGHS ABOVE NORMAL
BY ABOUT TEN DEGREES.
UPPER RIDGE AXIS BUILDS INTO THE CANADIAN MARITIMES SUN
NIGHT...STRENGTHENING THE LOW-LEVEL RIDGE ACROSS THE NE AND
ALLOWING FOR A BACKDOOR COLD FRONTAL PASSAGE. THIS SHOULD RESULT
IN MUCH COOLER CONDITIONS WORKING IN ON MON.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE WESTWARD EXTENT OF THE BACKDOOR COLD FRONT WILL BE A KEY
PLAYER IN DETERMINING IF THE AREA STAYS OUT OF CONVECTION ON MON
AND HOW COOL TEMPS GET. 00Z CYCLE SHOWS THE FRONT GETTING TO THE
LEE OF THE POCONOS AND CATSKILLS. THIS MAY RESULT IS SOME SHOWER
ACTIVITY OVER THE WESTERN PORTIONS OF THE AREA.
THE FRONT APPROACHES AS WARM FRONT TUE MORNING. THE FLOW ALOFT
TURNS MORE CYCLONIC...AND INCREASING MOISTURE AND LIFT COULD
PRODUCE SOME SHOWERS...PRIMARILY OVER THE WESTERN HALF OF THE CWA.
A TRAILING COLD FRONT APPROACHES TUE AFT AND IS PROGGED TO BE
THROUGH BY EARLY EVENING. THERE IS A GOOD CHANCE OF CONVECTION
ALONG AND AHEAD OF THE FRONT TUE.
HIGH PRESSURE BUILDS IN FOR WEDNESDAY THROUGH FRIDAY. A MODERATE
DOWNSLOPE FLOW SHOULD BE ABLE TO OFFSET SOME OF THE COLD AIR
ADVECTION...KEEPING HIGHS NEAR NORMAL ON WEDNESDAY. TEMPS ALOFT
THEN WARM UP ON THURSDAY AND FRIDAY...WITH HIGHS A LITTLE WARMER
THAN THOSE ON WEDNESDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A WARM FRONT LIFTS THROUGH THE REGION THIS AFTERNOON. A SURFACE
TROUGH THEN 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...EXCEPT FOR IFR
NEXT COUPLE OF HOURS AT KGON.
FOR TERMINALS W OF HUDSON HAVE GONE WITH PREVAILING SHRA/TEMPO
TSRA LATE THIS AFTERNOON/EARLY THIS EVENING. FOR TERMINALS E OF
THE HUDSON HAVE GONE WITH VCTS WITH TEMPO SHRA THIS EVENING.
WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT
WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. FOR NOW HAVE
CONTINUED WITH LOW END MVFR FORECAST (3SM/1000FT)...HOWEVER
CANNOT RULE OUT IFR...OR EVEN VFR FOR THAT MATTER.
WINDS MAINLY LIGHT AND VARIABLE OUTSIDE OF SEABREEZES THIS
AFTERNOON...AND SOUND BREEZE KLGA AND SEABREEZE KJFK/KBDR/KGON
LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON.
.OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY...
.SUNDAY AFTERNOON/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 5-10 KT BECOME 10-20 KT ON THE OCEAN WATERS THIS
AFTERNOON...THEN WILL DIMINISH TONIGHT. WITH A LIGHT PRES GRADIENT
OVER THE AREA THROUGH THE START OF THE NEW WEEK...SUB-SCA
CONDITIONS ON TAP WITH SEAS 2-4 FT ON THE OCEAN WATERS AND 1 FT
OR LESS ON THE SOUND/HARBOR/BAYS.
&&
.HYDROLOGY...
BASIN AVG RAINFALL OF 1/4 TO 1/2 INCH IS POSSIBLE THROUGH TONIGHT
WITH LOCALIZED HIGHER AMOUNTS AS A COMPLEX OF SHOWERS AND
THUNDERSTORMS MOVES IN FROM PA TONIGHT.
A QUARTER TO HALF INCH OF RAINFALL IS POSSIBLE LATE MONDAY NIGHT
THROUGH TUESDAY WITH A COLD FRONTAL PASSAGE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DW
NEAR TERM...DS/DW
SHORT TERM...DS/DW
LONG TERM...DW/JC
AVIATION...MALOIT
MARINE...MPS
HYDROLOGY...DW
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
400 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A WEAK COLD FRONT IS FORECAST TO MOVE THROUGH OUR AREA SUNDAY INTO
SUNDAY NIGHT. THE NEXT LOW PRESSURE SYSTEM CURRENTLY NEAR THE ROCKIES
IS EXPECTED TO PROGRESS EASTWARD ACROSS THE GREAT LAKES REGION,
SENDING A COLD FRONT THROUGH OUR AREA TUESDAY INTO TUESDAY NIGHT.
HIGH PRESSURE WILL THEN GRADUALLY BUILD EAST INTO OUR REGION FROM
MIDWEEK THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A DISORGANIZED AREA OF CONVECTION HAS BEEN STEADILY MOVING EASTWARD
THIS AFTERNOON THROUGH CENTRAL PENNSYLVANIA WHERE BULK SHEAR VALUES
ARE LESS THAN 25 KNOTS. AS THIS LINE MOVES CLOSER TO OUR REGION IT
WILL BEGIN TO INGEST MORE UNSTABLE AIR WITH BETTER BULK SHEAR IN
PLACE ALLOWING FOR SOMEWHAT MORE ORGANIZATION AND LONGEVITY.
EXPECTING THESE STORMS TO MOVE INTO OUR WESTERN ZONES OVER THE NEXT
COUPLE OF HOURS. FORECAST SOUNDINGS STILL SHOW LONG THIN CAPE
PROFILES WITH SOME DRY AIR IN THE MID-LEVELS. LATEST RUC DCAPE
VALUES ARE AROUND 800 TO 1000J/KG WITH STRONG TO ISOLATED SEVERE
WIND GUSTS THE MAIN THREAT TO ANY OF THESE STORMS. VERY HEAVY
RAINFALL IS ALSO EXPECTED AS THEY PUSH THROUGH WITH PWAT VALUES
RUNNING AROUND THE 99TH PERCENTILE FOR MID-MAY. THIS COUPLED WITH
VERY DRY CONDITIONS SHOULD ALLOW FOR MORE EFFICIENT RUNOFF TO OCCUR
WITH PONDING ON ROADWAYS AND POOR DRAINAGE LOCATIONS. FORTUNATELY
THE MEAN STEERING FLOW OF THESE STORMS IS ALLOWING THEM TO MOVE
RELATIVELY QUICKLY, AROUND 30 KNOTS TOWARDS THE EAST.
ONCE THESE STORMS EITHER PUSH OFF THE COAST OF BECOME ELEVATED IN
NATURE WITH THE LOSS OF DAYTIME HEATING MORE SCATTERED SHOWER
ACTIVITY IS EXPECTED THROUGH MOST OF THE LATE EVENING HOURS BEFORE
WE DRY OUT SOME. VERY MUGGY CONDITIONS WILL EXIST TONIGHT WITH AMPLE
MOISTURE IN THE LOW-LEVELS. PATCHY FOG IS POSSIBLE AS THE WINDS
DECOUPLE AND BECOME LIGHT AND VARIABLE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
ALMOST A CARBON COPY OF SATURDAY IN TERMS OF THE SHOWER/CONVECTION
THREAT DURING THE DAY...MAYBE NOT AS WIDESPREAD. WE WILL HAVE THE
MOISTURE IN PLACE WITH ANOTHER WELL ABOVE AVERAGE TEMPERATURE
FORECAST. ONE OF THE BIGGEST QUESTIONS IS THE POTENTIAL LACK OF
BETTER SURFACE BASED INSTABILITY WITH A PERSISTENT STRATOCU DECK IN
PLACE...MAYBE SOME BREAKS POSSIBLE AS THE WINDS VEER MORE TOWARDS
THE WEST DURING THE AFTERNOON. TEMPERATURES MAY END UP A TAD COOLER
WITH THE AMOUNT OF MOISTURE TRAPPED UNDER THE LOW-LEVEL INVERSION,
BUT A WARMER STARTING POINT SHOULD YIELD LOW-80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
DESPITE STARTING OUT UNDER THE AXIS OF AN UPPER LEVEL SHORTWAVE
RIDGE...THERE LOOK TO BE PLENTY OF OPPORTUNITIES FOR RAIN, AT
LEAST TO BEGIN THE LONG TERM PERIODS.
SUNDAY NIGHT...SHORTWAVE RIDGE PIVOTS OVERHEAD, WHILE AT THE
SURFACE, THE WEAK COLD FRONT CONTINUES TO SLIDE SOUTH OVER THE
REGION. THE COMBINATION OF MID AND UPPER LEVEL SUBSIDENCE, ALONG
WITH A NOCTURNAL INVERSION SHOULD HELP TO SUPPRESS OVERNIGHT
CONVECTION. THEREFORE, STAYED CLOSE TO THE PREVIOUS FORECAST WITH
PRECIP CHANCES DROPPING FROM 20 TO 50 PERCENT IN THE EVENING TO 10
TO 20 PERCENT AFTER MIDNIGHT.
MONDAY INTO TUESDAY...SURFACE LOW STILL EXPECTED TO TRACK ACROSS
THE GREAT LAKES REGION, WHILE IN THE MID AND UPPER LEVELS, THE
RIDGE SHIFTS OFF SHORE. PERSISTENT EASTERLY FLOW ON MONDAY
RESULTING IN LOW CLOUDS, MAY LIMIT SURFACE BASED INSTABILITY, BUT
ELEVATED INSTABILITY IS POSSIBLE. THEREFORE, INCLUDED THUNDERSTORM
MENTION ACROSS THE REGION, THOUGH WOULD EXPECT MOSTLY STRATIFORM
RAIN OR SHOWERS ON MONDAY. ON TUESDAY HOWEVER, WINDS SHIFT TO
SOUTHERLY AND SOUTHWESTERLY AS A PRE FRONTAL TROUGH ARRIVES
TUESDAY AFTERNOON. THE COLD FRONT SHOULD ARRIVE TUESDAY
EVENING/OVERNIGHT. THERE ALSO APPEARS TO BE SUBSTANTIAL SPEED
SHEAR (20 TO 35 KT) THROUGH THE DAY. THERE ARE A FEW POTENTIAL
LIMITATIONS TO CONVECTION THOUGH, PRIMARILY MEAGER LAPSE RATES
ABOVE THE BOUNDARY LAYER. PRECIPITABLE WATER VALUES SHOULD BE
WELL ABOVE NORMAL, AND THE WARM CLOUD LAYER IS EXPECTED TO BE
QUITE DEEP. AND WHILE FORECAST STORM MOTIONS SHOULD BE AROUND 20
TO 25 KT, THERE IS THE POTENTIAL FOR TRAINING STORMS IF THE PRE
FRONTAL TROUGH SERVES AS A FOCUS FOR CONVECTIVE INITIATION.
THEREFORE, WILL ADD MENTION IN THE HWO OF HEAVY RAIN THREAT.
WEDNESDAY THROUGH SATURDAY...FRONT CLEARS OUT QUICKLY BY EARLY
WEDNESDAY MORNING, LEAVING THE REGION UNDER A MOSTLY DRY PATTERN
AS A SURFACE HIGH IS EXPECTED TO BUILD IN OVER MUCH OF THE
NORTHEAST. A FEW CAVEATS, HOWEVER. FIRST, A PAIR OF SHORTWAVE
TROUGHS ON THE BACK SIDE OF THE DEPARTING UPPER LEVEL TROUGH MAY
DIG OVER OUR REGION, BUT THE TIMING OF THE TROUGHS IS UNCERTAIN,
AND LOW LEVEL MOISTURE MAY BE LIMITED WITH PERSISTENT DOWN SLOPE
FLOW. SECOND, BOTH THE GFS AND ECMWF SHOW A COASTAL LOW DEVELOPING
OVER THE CAROLINA/VIRGINIA COASTS BY FRIDAY. DEPENDING ON HOW FAR
NORTH THIS DEVELOPS, IT COULD RESULT IN PRECIP ACROSS THE DELMARVA
PENINSULA AND FAR SOUTHERN NJ.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THIS EVENING - TONIGHT...MOSTLY VFR WITH SOME MVFR/IFR SHOWERS AND
THUNDERSTORMS POSSIBLE THIS EVENING. STILL THINKING MOST OF THE
THUNDER ACTIVITY OCCURS AROUND 20 TO 00Z THIS EVENING FROM WEST TO
EAST. AFTERWARDS LINGERING SHOWERS ARE POSSIBLE ALLOWING CONDITIONS
TO DETERIORATE TOWARDS MVFR AFTER MIDNIGHT...LOW CONFIDENCE ON MVFR
CONDITIONS TONIGHT.
SUNDAY...ANY MVFR RESTRICTIONS SHOULD LIFT/BURN OFF BY LATE MORNING
ALLOWING FOR MORE VFR CONDITIONS. CONTINUED SOUTHWESTERLY FLOW WILL
KEEP MOISTURE STREAMING INTO THE REGION SO WE MAY NOT BREAK OUT MUCH
DURING THE DAY. MORE SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE DURING THE AFTERNOON HOURS.
OUTLOOK...
SUNDAY NIGHT INTO MONDAY...WIDESPREAD MVFR AND LOCALIZED IFR
CONDITIONS WITH LOW CLOUDS AND SHOWERS POSSIBLE FOR MUCH OF THE
PERIOD. CHANCE FOR THUNDERSTORMS MONDAY AFTERNOON AND EVENING.
TUESDAY...THUNDERSTORMS LIKELY. MVFR AND LOCALIZED IFR CONDITIONS
EXPECTED TO CONTINUE.
WEDNESDAY AND THURSDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
TONIGHT - SUNDAY...SUB-SCA CONDITIONS ACROSS THE WATERS EXPECTED.
SOUTHERLY FLOW WILL CONTINUE THROUGH SUNDAY ALLOWING SEAS TO BUILD
UPWARDS OF 4 FEET BY SUNDAY AFTERNOON. WITH COLDER THAN NORMAL WATER
TEMPERATURES AND A WARMER AIRMASS IN PLACE EXPECTING THE AMOUNT OF
MIXING TO BE KEPT TO A MINIMUM...LESS THAN 20 KNOTS.
OUTLOOK...
MONDAY AND TUESDAY...SUB SCA CONDITIONS LIKELY. HOWEVER, A FEW
GUSTS ABOVE 20 KT ARE POSSIBLE ON MONDAY ON THE OCEAN WATERS, AND
HIGHER GUSTS WILL BE POSSIBLE IN THE VICINITY OF ANY
THUNDERSTORMS.
WEDNESDAY AND THURSDAY...WINDS AND SEAS SHOULD REMAIN BELOW SCA
CRITERIA.
&&
.RIP CURRENTS...
THE RISK FOR RIP CURRENTS IS BORDERLINE LOW TO MODERATE FOR THE
NJ COAST ON SATURDAY AFTERNOON.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JOHNSON
NEAR TERM...HEAVENER
SHORT TERM...HEAVENER
LONG TERM...JOHNSON
AVIATION...HEAVENER/JOHNSON
MARINE...HEAVENER/JOHNSON
RIP CURRENTS...O`HARA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
228 PM EDT SAT MAY 16 2015
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN AMPLIFIED UPPER LEVEL
PATTERN OVER THE CONUS TODAY. DEEP AND POTENT UPPER TROUGH IS
SPINNING OVER THE INTERMOUNTAIN WEST/WESTERN PLAINS...WITH
DOWNSTREAM STRONG RIDGING ALOFT OVER THE EASTERN THIRD OF THE
NATION. WV IMAGERY SHOWS A STRONG SHORTWAVE ROUNDING THE BASE OF
THE WESTERN TROUGH AND ABOUT TO EJECT NORTHEASTWARD OVER THE
CENTRAL PLAINS. THIS ENERGY IS FORECAST TO BRING A POTENTIAL
SIGNIFICANT SEVERE WEATHER OUTBREAK TO PARTS OF TEXAS/OK/KS LATER
TODAY. WHILE THIS WEATHER SYSTEM AND ITS ASSOCIATED ORGANIZED
SEVERE WEATHER THREAT WILL STAY WELL TO OUR NORTHWEST THIS
WEEKEND...WE IN WEST-CENTRAL AND SOUTHWEST FLORIDA WILL BE
DEALING WITH MORE OF OUR OWN LATE DAY SEA-BREEZE STORMS. MORE INFO
ON OUR THUNDERSTORM THREAT IN THE SHORT TERM DISCUSSION BELOW.
AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO
THE WEST INTO THE GA/CAROLINA COAST...PROVIDING OUR REGION WITH A
GENERAL EAST TO SOUTHEAST LOW LEVEL FLOW. SIMILAR TO PREVIOUS
DAYS...THIS EASTERLY SYNOPTIC FLOW WILL FAVOR THUNDERSTORM
DEVELOPMENT ALONG THE FLORIDA WEST COAST SEA-BREEZE DUE TO THE
ADDED CONVERGENCE AND EVENTUAL ARRIVAL/COLLISION OF THE EAST
COAST SEA- BREEZE BOUNDARY.
&&
.SHORT TERM...
REST OF TODAY...WITHIN THE LARGE SCALE PRESSURE GRADIENT ON THE
SOUTHERN PERIPHERY OF THE ATLANTIC RIDGE TO OUR NORTH...WE CAN
ANALYZE A WEAK INVERTED TROUGH/CONVERGENCE ZONE ALONG THE
SOUTHEAST FL COAST. SCATTERED SHOWERS BEGAN MIGRATING WESTWARD
FROM THIS FEATURE INTO THE SOUTH-CENTRAL ZONES
(HIGHLANDS/HARDEE/DESOTO) DURING THE EARLY AFTERNOON...AND NOW
MOVING OVER TOWARD THE PUNTA GORDA/FORT MYERS AREA. SO...A FEW
SHOWERS AROUND FOR THE SOUTHERN ZONES FROM THIS ACTIVITY THROUGH
MID AFTERNOON...BUT THE MAIN CONVECTIVE DEVELOPMENT IS STILL NOT
EXPECTED UNTIL LATER IN THE AFTERNOON/EARLY EVENING HOURS. BEFORE
THE EXPECTED CONVECTIVE BURST...MUCH OF THE REGION FROM THE I-4
CORRIDOR NORTHWARD WILL SEE A MIX OF SUN AND CLOUDS WITH
TEMPERATURES INTO THE 80S.
FORECASTING SEA-BREEZE THUNDERSTORMS IS NEVER A PERFECT SCIENCE...
BUT HERE IS THE BREAKDOWN LEADING TO THE CURRENT FORECAST. WE START
WITH THE SYNOPTIC LOW LEVEL (1000-700MB) FLOW...WHICH TODAY IS
MODERATE FROM THE EAST/SOUTHEAST. THIS FLOW REGIME DURING THE WARM
SEASON FAVORS LATE DAY THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA
WEST COAST...WITH DRIER CONDITIONS BY LATE AFTERNOON FOR THE FLORIDA
EAST COAST. THE WEST COAST IS FAVORED DUE TO THE ENHANCED
CONVERGENCE OF THE LARGE SCALE FLOW HEADING WESTWARD...AND THE WEST
COAST SEA-BREEZE TRYING TO MOVE EAST. EVENTUALLY THE EAST COAST SEA-
BREEZE...SPED ALONG BY THE LARGE SCALE FLOW ARRIVES AT THE I-75
CORRIDOR AND FURTHER ENHANCES THE LOW LEVEL FOCUS/CONVERGENCE.
ALOFT...THERE IS NOT REALLY ANY SIGNIFICANT HOSTILE LAYER TOWARD
DEEP CONVECTION...WITH MINIMUM THETAE VALUES NO LOWER THAN AROUND
320K (FAIRLY TYPICAL FOR MID MAY).
THE CURRENT FORECAST FAVORS THE HIGHEST RAIN CHANCES LATE
AFTERNOON/EVENING FROM TAMPA BAY SOUTHWARD DUE TO THE FACT THAT THE
FLOW JUST ALOFT OFF THE SURFACE SEEMS TO BE A BIT STRONGER FOR THE
NATURE COAST...AND IS BORDERLINE STRONG ENOUGH TO PREVENT AN
ORGANIZED SEA-BREEZE...OR TO KEEP IT SUPPRESSED JUST OFFSHORE.
LIGHTER FLOW FURTHER SOUTH SHOULD ALLOW SOME INLAND PENETRATION OF
THE SEA-BREEZE CIRCULATION SO THAT THE MORE EFFICIENT LOW LEVEL
FOCUS ZONE TO ENHANCE LIFT APPEARS TO SET UP FROM PASCO/PINELLAS
COUNTIES SOUTHWARD. THERE IS ACTUALLY VERY GOOD AGREEMENT AMONG THE
HIRES CONVECTION ALLOWING GUIDANCE FROM NCEP AND LOCAL RUNS TO
SUPPORT THIS SCENARIO. IN FACT...THE LAST FEW RUNS OF THE HRRR HAVE
BEEN FOCUSING MAINLY FROM MANATEE COUNTY SOUTHWARD. SINCE...THE
HIRES GUIDANCE ARE SUBJECT TO INFLUENCE FROM THEIR OWN EARLIER
CONVECTION...AND THE PARAMETERIZED MODELS ARE STILL SHOWING
DEVELOPMENT A BIT FURTHER NORTH...HAVE INCLUDED THE TAMPA BAY/PASCO
AREA IN THE LIKELY RAIN/THUNDER CHANCES. WILL SEE HOW ALL THIS WORKS
OUT AS WE GET LATER INTO THE DAY...BUT BASED ON ALL AVAILABLE INFO
AND PATTERN RECOGNITION...FEEL THIS IS THE BEST FORECAST.
HAVE ALSO BEEN FAIRLY IMPRESSED WITH THE GENERAL UPDRAFT VELOCITY
VALUES OUT OF THE HRRR FOR LATER TODAY. PEAK VALUES ALONG THE SUN
COAST TO THE SOUTH OF TAMPA BAY HAVE BEEN IN THE 14-18M/S
RANGE...WHICH IS FAIRLY SUBSTANTIAL FOR LOW SHEAR PULSE
CONVECTION. WITH THIS IN MIND WILL NEED TO BE MINDFUL OF PRECIP
LOADING AND DOWNBURST POTENTIAL WITH STRONGER CELLS. ALSO...THE
POTENTIAL FOR SOME EFFICIENT LIGHTNING PRODUCERS IS ALSO THERE.
WHAT IS LEFT OF THE STORMS PUSH OFFSHORE INTO THE COASTAL WATERS BY
LATE EVENING...FOLLOWED BY A GENERALLY QUIET...DRY AND SEASONABLY
WARM OVERNIGHT PERIOD.
SUNDAY... WE SEE ONE MORE DAY WITH THIS BROKEN RECORD PATTERN OF
EASTERLY SYNOPTIC FLOW BEFORE THE PATTERN BEGINS TO TRANSITION.
ONE THING ADVERTISED BY THE CURRENT MODEL SUITE...IS A MORE
UNIFORM LIGHT FLOW ABOVE THE SURFACE FOR THE AFTERNOON
HOURS...RESULTING IN A MORE UNIFORM ORGANIZATION TO THE SEA-BREEZE
ALONG OUR COASTS. THEREFORE...AFTER A QUIET MORNING AND EARLY
AFTERNOON...YET ANOTHER ROUND OF LATE DAY STORMS IS ANTICIPATED
ALONG THE I-75 CORRIDOR. AS IT STANDS NOW...APPEARS WE SHOULD SEE
A SCATTERING OF SHOWERS/STORMS PROGRESS FROM EAST TO WEST ACROSS
THE FORECAST AREA ALONG THE EAST COAST SEA BREEZE DURING THE
EARLY/MID AFTERNOON...WITH CONVECTION RAMPING UP TO NUMEROUS
THUNDERSTORMS ALONG AND INSIDE THE I-75 CORRIDOR AFTER AROUND 400
PM.
&&
.LONG TERM (MONDAY THROUGH NEXT SATURDAY)...ALOFT - RIDGING GENERALLY
DOMINATES THE GULF AND FL...ALTHOUGH IT BRIEFLY WEAKENS AND DRIFTS BACK
WEST MID-WEEK...AS A COUPLE OF LOWS/TROUGHS TRAVERSES THE NORTHERN TIER
OF STATES. AT THE SURFACE - HIGH PRESSURE WAS OVER CENTRAL CANADA WITH
A FRONT THAT ARCED FROM THE UPPER GREAT LAKES THROUGH THE SOUTHERN HIGH
PLAINS THEN BACK UP THROUGH THE PACIFIC NORTHWEST...THIS HIGH DROPS
DOWN INTO THE MID-MISSISSIPPI VALLEY THEN TRACKS EAST WITH THE FRONT
SAGGING IN ALONG THE AL/GA/FL BORDER BY THE END OF THE WORK WEEK AND IN
ACROSS NORTHERN FRI SAT. ATLANTIC HIGH PRESSURE...WITH AN AXIS
INITIALLY ALONG THE NORTHERN FL LINE...SINKS SOUTH WITH IT/S AXIS
SETTLING IN ACROSS CENTRAL FL THEN SOUTH FL.
THE FORECAST PHILOSOPHY WILL BE BASED ON A GENERALLY MOIST AIRMASS
IN PLACE...WITH MODEL PWAT VALUES RUNNING ABOVE 1.6 INCHES AND UP
TO NEAR 2.0 INCHES AT TIMES. THE EXCEPTION MAY BE SAT WHEN THE
FRONT SAGS INTO NORTH FL WITH SOME DRIER AIR BEHIND IT.
HOWEVER...AT THIS POINT IN THE FORECAST THE GFS BRINGS THE FRONT
INTO FL WHILE THE ECMWF HOLDS IT ON THE STATE LINE OR ABOVE. THE
SURFACE RIDGE AXIS TRACKING SOUTH WITH GRADUALLY TRANSITIONING
FLOW FROM SOUTHEASTERLY WITH SEA BREEZES TO WESTERLY BY FRI. BUT
AGAIN...BASED ON THE FASTER GFS...FLOW SHIFTS AROUND TO
NORTHEASTERLY BY THE END OF THE PERIOD. SHOWERS AND THUNDERSTORMS
WILL BE IN THE SCATTERED RANGE WITH THE HIGHEST COVERAGE SWITCHING
FROM COASTAL TO MORE INLAND THROUGH THE WORK WEEK. ABOVE NORMAL
TEMPERATURES WILL CONTINUE.
&&
.AVIATION...
CONDITIONS ARE QUIET WITH PREVAILING VFR ONGOING LATE
THIS MORNING ACROSS WEST CENTRAL AND SW FLORIDA. HOWEVER...THESE
CALM CONDITIONS ARE NOT EXPECTED TO LAST THE REMAINDER OF THE DAY.
SIMILAR TO PREVIOUS DAYS...RAPID THUNDERSTORM DEVELOPMENT IS EXPECTED
ALONG THE I-75 CORRIDOR AFTER 20Z...WITH STORMS THEN PUSHING SLOWLY
TO THE WEST. A PERIOD OF IFR OR LOWER VIS/CIGS ALONG WITH GUSTY
WINDS AND FREQUENT LIGHTING IS POSSIBLE FOR ANY TERMINAL LATER
TODAY. WILL ADD THUNDER TEMPO GROUPS WITH 18Z PACKAGE.
&&
.MARINE...
A GENERAL EAST TO SOUTHEAST WINDS FLOW WILL REMAIN IN
PLACE THROUGH SUNDAY WITH WINDS TURNING ONSHORE AT THE COAST EACH
AFTERNOON AS THE SEA BREEZE DEVELOPS. THUNDERSTORMS ARE EXPECTED
TO RAPIDLY DEVELOP NEAR THE COAST DURING THE LATE AFTERNOON AND
EVENING HOUR BOTH TODAY AND SUNDAY...THEN PUSH OFFSHORE DURING THE
NIGHTTIME HOURS. BOATERS ENJOYING THE COASTAL WATERS OF THE
FLORIDA WEST COAST SHOULD KEEP AND EYE TO THEIR EAST DURING THE
LATE DAY HOURS THIS WEEKEND...AND BE PREPARED TO SEEK SAFE HARBOR
SHOULD THREATENING WEATHER ADVANCE. HEADING THROUGH THE UPCOMING
WORK WEEK...WINDS WILL SHIFT MORE WESTERLY...KEEPING MOST OF THE
THUNDERSTORM ACTIVITY INLAND.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE
HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. LATE AFTERNOON
AND EVENING THUNDERSTORMS WILL BE MOST NUMEROUS NEAR THE COAST
FROM TAMPA BAY SOUTHWARD TODAY...THEN ALONG THE ENTIRE COASTAL
I-75 CORRIDOR FOR LATE SUNDAY. THE PATTERN WILL THEN BEGIN TO
TRANSITION TO ONE SUPPORTING LATE DAY STORMS FURTHER INLAND...WITH
DRIER CONDITIONS NEAR THE COAST.
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 89 73 89 / 30 60 50 20
FMY 72 90 72 90 / 40 60 30 30
GIF 72 90 71 91 / 10 40 10 20
SRQ 72 87 72 88 / 40 60 50 20
BKV 69 90 69 90 / 20 60 40 30
SPG 75 89 75 89 / 40 60 50 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SHORT TERM/AVIATION/FIRE WEATHER/MARINE...14/MROCZKA
LONG TERM/DECISION SUPPORT...09/RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1234 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 947 AM CDT SAT MAY 16 2015
SHOWERS INCREASING IN COVERAGE TO OUR SOUTH...AND HAVE SEEN
SCATTERED SHOWERS ALSO DEVELOPING MORE WITHIN OUR FORECAST AREA.
SO FAR THUNDER UPSTREAM HAS BEEN RATHER MINIMAL...AND SURFACE
BASED CAPE VALUES PROGGED BY THE RAP MODEL EXPECTED TO BE LESS
THAN 500 J/KG FROM ABOUT I-57 EASTWARD. WITH NO SUBSTANTIAL
HEATING IN THAT AREA...HAVE DOWNPLAYED THE THUNDER POTENTIAL
ACROSS THE EASTERN CWA THROUGH THE AFTERNOON. FURTHER WEST...
CAPES 1000-1500 J/KG EXPECTED AND THERE ARE ALSO SOME SUBSTANTIAL
BREAKS IN THE CLOUDS ACROSS SOUTHERN IOWA AND NORTHEAST
MISSOURI...SO HAVE MAINTAINED GENERAL SHOWER/THUNDERSTORM MENTION
ACROSS THE REMAINDER OF THE FORECAST AREA. WITH RAIN ACROSS THE
SOUTHEAST CWA EXPECTED TO BECOME FAIRLY WIDESPREAD...HAVE LOWERED
HIGHS IN THAT AREA A COUPLE DEGREES...WITH MOST OF THE REMAINING
CWA GENERALLY EXPECTED TO REACH AROUND 80 DEGREES.
&&
.SHORT TERM...(TODAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
ANOTHER RELATIVELY WARM AND HUMID DAY IS ANTICIPATED ACROSS CENTRAL
AND SOUTHEAST ILLINOIS TODAY AS SOUTHERLY LOW LEVEL FLOW PERSISTS.
DAYTIME HIGHS MAY BE A FEW DEGREES COOLER THAN YESTERDAY, ESPECIALLY
ACROSS SOUTHEAST ILLINOIS WHERE CLOUD COVER WILL BE THICKEST AND
RAINFALL MOST WIDESPREAD, BUT MOST LOCATIONS SHOULD STILL CRACK THE
80 DEGREE MARK.
AS FAR AS SHOWER/STORM POTENTIAL TODAY, GIVEN THE FAIRLY JUICED UP
LOW-LEVEL AIRMASS AND LACK OF APPRECIABLE CAPPING, IT WILL NOT TAKE
MUCH TO POP OFF SOME CONVECTION. PLAN TO CARRY AT LEAST CHANCE POPS
AREAWIDE TODAY GIVEN THIS POTENTIAL. MODEL PROGS SUGGEST MOST OF THE
FORECAST AREA SHOULD SEE DIURNALLY INDUCED CAPE VALUES OF AT 1500
J/KG, ALTHOUGH SHEAR PROFILES SHOULD BE QUITE WEAK OVER THE NORTHERN
2/3 OR SO OF THE REGION. THE BETTER FORCING ACROSS SOUTHEAST
ILLINOIS WILL COME COURTESY OF A WEAK SHORT WAVE LIFTING NORTHEAST
FROM THE MID-MISSISSIPPI RIVER VALLEY. HAVE BUMPED POPS UP TO
CATEGORICAL SOUTH OF I-70 FOR THE MIDDAY/EARLY AFTERNOON HOURS TO
ACCOUNT FOR THE PASSAGE OF THIS WAVE.
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
DIURNALLY ENHNANCED CONVECTION THIS AFTERNOON AND EARLY EVENING WILL
DIMINISH IN COVERAGE AFTER SUNSET SIMILAR TO WHAT HAPPENED FRIDAY
EVENING AS INSTABILITY WANES. WILL CARRY HIGHEST POPS IN
SOUTHEAST IL THIS EVENING ESPECIALLY BEFORE DARK WITH SHORT WAVES
NEAR EASTERN/SE IL EARLY THIS EVENING AROUND 00Z/7 PM. MILD LOWS
TONIGHT IN THE MID TO UPPER 60S WITH MILDEST READINGS SW AREAS.
CUTOFF LOW OVER THE CENTRAL ROCKIES TO EJECT NE INTO MN BY SUNDAY
EVENING AND HAS A PREFRONTAL TROF PUSHING EAST TOWARD THE MS RIVER.
THIS TO INCREASE CHANCES OF CONVECTION FROM WEST TO EAST DURING THE
DAY SUNDAY AND THEN DIMINISH FROM WEST TO EAST DURING SUNDAY NIGHT.
SPC HAS SLIGHT RISK OF SEVERE STORMS SUNDAY AFTERNOON/EVENING FROM
BLOOMINGTON TO TAYLORVILLE WEST WHERE STRONGER BULK SHEAR OF 35-45
KTS OCCURS ALONG WITH INCREASE INSTABILITY WITH CAPES PEAKING AROUND
2500 J/KG SUNDAY AFTERNOON. WARM HIGHS IN THE LOWER 80S SUNDAY WITH
BREEZY SSW WINDS AND MUGGY DEWPOINTS IN THE MID TO UPPER 60S.
MAIN COLD FRONT TO PUSH EAST ACROSS IL DURING MONDAY AND BRINGS BEST
CHANCES OF SHOWERS AND THUNDERSTORMS TO AREAS EAST OF I-55. SPC
KEEPS MARGINAL RISK OF SEVERE EAST OF IL OVER PARTS OF INDIANA ON
MONDAY. HAVE BUMPED UP THE HIGHS ON MONDAY A FEW DEGREES WITH MID
70S FROM IL RIVER NW TO LOWER 80S IN EASTERN IL.
DRIER...COOLER AND LESS HUMID AIR USHERS INTO IL DURING MONDAY NIGHT
AND TUE BEHIND THE COLD FRONT. LOWS MONDAY NIGHT RANGE FROM MID 40S
NW OF IL RIVER TO NEAR 55F FAR SE IL NEAR WABASH RIVER BY
LAWRENCVILLE. HIGHS TUE IN THE MID 60S CENTRAL IL AND 65-70F IN
SOUTHEAST IL. A COOL NIGHT AHEAD FOR TUE NIGHT WITH LOWS IN THE MID
TO UPPER 40S.
EXTENDED MODELS TRY TO BRING SOME QPF BACK INTO PARTS OF CENTRAL AND
ESPECIALLY SOUTHERN/SW IL WED AND THEN SUPPRESS IS SOUTHWARD BY THU
WITH SOME ENERGY EJECTING FROM THE UPPER LEVEL TROF/LOW NEAR CA AND
MOVING INTO THE MID/LOWER MS RIVER VALLEY. WILL KEEP POPS LOW FROM
WED-THU WITH MAINLY SLIGHT CHANCES, THOUGH SW AREAS HAVE CHANCE POPS
30-40% WED AND WED EVENING. HIGHS IN THE LOW TO MID 60S WED AND 65
TO 70F ON THU. TEMPS CONTINUE TO SLOWLY MODIFY FRIDAY WITH HIGHS
MAINLY IN THE LOWER 70S AND DRY CONDITIONS WITH WEAK HIGH PRESSURE
IN THE CENTRAL PLAINS AND RIDGING EAST TOWARD IL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1234 PM CDT SAT MAY 16 2015
SOME MVFR CEILINGS LINGER AROUND KBMI/KCMI AT MIDDAY...BUT THESE
SHOULD CONTINUE TO IMPROVE. ASIDE FROM A CLUSTER OF STORMS THAT
HAVE RECENTLY PASSED KBMI...CONVECTION REMAINS RATHER ISOLATED AND
DISORGANIZED. THE CURRENT STATE OF THE ATMOSPHERE DOES NOT HAVE
ANY PARTICULAR BOUNDARIES OR FRONTS TO FOCUS THE ACTION...THUS
WILL MAINTAIN THE VCTS MENTIONS FOR NOW...AND WILL UPDATE WHEN
THE CONVECTION STARTS TO GET ORGANIZED. MOST OF THE HIGH-
RESOLUTION MODEL GUIDANCE LARGELY HAS THE THREAT OUT OF CENTRAL
ILLINOIS BY 00Z AND HAVE KEPT THE OVERNIGHT HOURS DRY. SOME
QUESTION AS TO HOW LOW THE CEILINGS WILL GET AND WILL GO WITH
LOW-END MVFR CEILINGS AT ALL SITES. LOW-LEVEL WIND SHEAR IS
MARGINAL FOR TONIGHT...BUT WILL HAVE TO MONITOR THIS POTENTIAL
OVER THE NEXT FEW HOURS. SOME OF THIS LOW LEVEL JET WILL WORK
TOWARD THE SURFACE SUNDAY MORNING...AND SOUTHERLY GUSTS SHOULD
START REACHING 20 KNOTS OR SO BY MID MORNING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BAK
LONG TERM...07
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
219 PM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 149 PM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT
AS A STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM
CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES
THIS AFTERNOON WILL REACH AROUND 75...WITH LOW TEMPERATURES
TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE
FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST
MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST
CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO
FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH
CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS
SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE
SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS
WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER
OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE
MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS
WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER
SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO
CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT
SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT
EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR
TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME
ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO
WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 215 PM EDT SAT MAY 16 2015
LOTS OF WEAK ENERGY DISTURBANCES AND AREAS OF DIFFERENTIAL HEATING
ALLOWING DISORGANIZED BANDS OF SHOWERS AND A FEW STORMS TO DEVELOP
AND PERSIST OVER THE AREA. ALSO...MFR CLOUDS HANGING AROUND UNDER
A DEEP COLUMN OF MOISTURE WHICH WAS SATURATED OR NEARLY SATURATED
UP TO 400 MB AS INDICATED ON SOME ACARS/AFCT SOUNDINGS. REALLY
HARD TO PICK A TIME FOR SHOWERS OR A STORMS AT EITHER TAF SITE.
WENT FAIRLY CONSERVATIVE ON PLACING ANY SHOWERS OR STORMS AT TAF
SITES AS OVERALL SHOWER/STORM COVERAGE SHOULD NOT BE THAT GREAT.
HOWEVER... MADE TAFS MUCH MORE PESSIMISTIC WITH ANY CLEARING OF
MVFR CLOUDS. HAVE BROUGHT BOTH SBN AND FWA SITES DOWN TO LOW
MVFR... WITH THE POSSIBILITY INCREASING FOR IFR CONDITIONS AT SOME
POINT TONIGHT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MCD/SKIPPER
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...SKIPPER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
205 PM CDT SAT MAY 16 2015
...UPDATED LONG TERM 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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1200 PM CDT SAT MAY 16 2015
CIGS SHOULD BE PRIMARILY VFR. CANNOT RULE OUT TEMPORARY IFR
CONDITIONS LATER THIS AFTERNOON IN ASSOCIATION WITH +TSRA. THIS
WILL BE LOCALIZED AND NOT THE PREVAILING FLIGHT CATEGORY. WILL
CONTINUE WITH CB/VCTS GROUPS FOR KHYS AND KGCK AND USE A TEMPO
GROUP FOR KDDC FOR STORMS THIS EVENING. SOUTHERLY WINDS 15-25 KT
TODAY WILL BECOME SOUTHWESTERLY 10-15 KT THROUGH THE OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 82 49 70 / 70 0 0 10
GCK 50 80 47 69 / 60 0 0 0
EHA 48 79 47 69 / 10 0 0 0
LBL 50 81 50 73 / 20 0 0 0
HYS 53 80 48 67 / 80 0 0 0
P28 56 83 54 76 / 80 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...HUTTON
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
128 PM CDT SAT MAY 16 2015
...UPDATED SHORT TERM...
.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 THROUGH FRIDAY)
ISSUED AT 234 AM CDT SAT MAY 16 2015
FAIR WEATHER CAN BE EXPECTED SUNDAY IN THE WAKE OF THE
AFOREMENTIONED UPPER LEVEL TROUGH, ALONG WITH 10-15 KT SOUTHWEST
WINDS AND HIGHS IN THE UPPER 70S TO MID 80S. ANOTHER STRONG UPPER
LEVEL STORM SYSTEM WILL PROGRESS INTO THE SOUTHWESTERN UNITED
STATES BY LATE MONDAY, AND AHEAD OF THIS FEATURE, A COLD FRONT
WILL PASS THROUGH WESTERN KANSAS. HIGH TEMPERATURES WILL FALL INTO
THE UPPER 60S MONDAY NEAR INTERSTATE 70, WITH MID 70S IN SOUTH
CENTRAL KANSAS. AS THE NEXT UPPER LEVEL STORM SYSTEM APPROACHES ON
TUESDAY, LOW LEVEL MOISTURE WILL INCREASE, LEADING TO INCREASED
CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY AND TUESDAY NIGHT.
HIGH-END SEVERE STORMS ARE NOT EXPECTED GIVEN THE COOL AIRMASS IN
PLACE ACROSS WESTERN KANSAS, BUT MARGINALLY SEVERE ELEVATED
THUNDERSTORMS CANNOT BE RULED OUT. HIGH TEMPERATURES WILL PROBABLY
BE IN THE UPPER 50S TO 60S TUESDAY.
ANOTHER BREAK IN THE RAIN MAY WILL PROBABLY OCCUR WEDNESDAY AND
THURSDAY BEFORE THE NEXT UPPER LEVEL SYSTEM APPROACHES FROM THE
WEST. HIGHS OUGHT TO BE IN THE 60S TO LOWER 70S WITH LOWS IN THE
40S TO LOWER 50S. WIDESPREAD SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED WITH THIS SYSTEM FRIDAY AND SATURDAY; AND SOME OF THE
STORMS SATURDAY MAY BE SEVERE AS WARMER AND MOIST AIR MOVES INTO
WESTERN KANSAS FROM THE SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1200 PM CDT SAT MAY 16 2015
CIGS SHOULD BE PRIMARILY VFR. CANNOT RULE OUT TEMPORARY IFR
CONDITIONS LATER THIS AFTERNOON IN ASSOCIATION WITH +TSRA. THIS
WILL BE LOCALIZED AND NOT THE PREVAILING FLIGHT CATEGORY. WILL
CONTINUE WITH CB/VCTS GROUPS FOR KHYS AND KGCK AND USE A TEMPO
GROUP FOR KDDC FOR STORMS THIS EVENING. SOUTHERLY WINDS 15-25 KT
TODAY WILL BECOME SOUTHWESTERLY 10-15 KT THROUGH THE OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 82 49 70 / 70 0 0 10
GCK 50 80 47 69 / 60 0 0 0
EHA 48 79 47 69 / 10 0 0 0
LBL 50 81 50 73 / 20 0 0 0
HYS 53 80 48 67 / 80 0 0 0
P28 56 83 54 76 / 80 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1236 PM CDT Sat May 16 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CDT SAT MAY 16 2015
A broad upper level low was located across NV, UT and AZ early this
morning. A 65KT mid level jet max was lifting northeast across
eastern NM into western KS. The strong ascent ahead of this jet max
has helped to develop a line of showers and thunderstorms from
central NE, south-southwest into west TX. Most numerical models show
this line weakening as it moves east into a more stable airmass
across eastern KS through the morning hours.
A stronger H5 trough located along the southern base of the upper
level low will lift northeast across eastern NM into the northern TX
PNHDL through the late morning hours. Several numerical models all
show an area of scattered to numerous thunderstorms developing ahead
of a surface dryline across the eastern TX PNHDL through the mid
and late morning hours. These storms lift northeast and intensify
through the early and mid afternoon hours, as they move northeast
across western OK into south central KS. The 5Z HRRR shows this area
of thunderstorms moving northeast into the western counties of the
CWA by 20Z. Most numerical models show the atmosphere destabilizing
early this afternoon across the CWA, after the weaker storms from
this morning dissipate or lift off to the northeast. the WRF runs,
NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks
fairly weak with most models forecasting less than 100m2/s2 of 0-1KM
SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS
during the afternoon. Therefore, the environment will be favorable
for severe thunderstorms this afternoon. Another question will be
the mode of convection. If a complex of storms develops across
northwest OK late this morning and maintains itself northeast
across the CWA than any tornado threat will be quite low. Though
stronger updrafts within a QLCS or complex of thunderstorms would
produce large hail and damaging wind gusts. The HRRR and NAM 4KM
simulated reflectivity forecast more scattered to isolated
thunderstorms developing across north central OK and south central
KS early this afternoon, and moving northeast into the southwest
and southern counties of the CWA after 22Z. I suppose if we see
discrete supercells than there will be a chance for tornadoes
along with the large hail and damaging wind gusts.
Late this afternoon most models show thunderstorms developing along
the Pacific front/dryline across west central KS and western OK. The
environment will really improve ahead of the dryline late this
afternoon, with much stronger low-level vertical wind shear. Any
discrete supercells that develop along the Pacific front/dryline
across west central KS and western OK will have a chance to produce
tornadoes. Through the evening hours these discrete to scattered
supercell thunderstorms may congeal into line segments or a QLCS and
move northeast into the western counties of the CWA during the mid
evening hours. If discrete supercells move into the western counties
this evening, then there will be a chance for tornadoes. I suppose
if a QLCS develops there is a potential for meso-vortices tornadoes.
Cloud cover will probably keep high temperatures in the mid to
upper 70s.
Tonight, The upper low and lead H5 trough will lift northeast into
southwest NE. Line segments of thunderstorms or a QLCS will move
east across the remainder of the CWA during the late evening hours
into the early morning hours of Sunday. The primary hazard will be
large hail, damaging winds and heavy rainfall.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CDT SAT MAY 16 2015
On Sunday the dry slot will work across the area with lower
dewpoints but daytime highs should still reach to around 80 given
mixing and expected sun. The cold front will finally move across
the area Sunday night and it should pass through dry however there
are some signals that precip may develop along it toward Mon
morning southeast of the area. For now will keep conds dry and
with CAA on Monday expect much cooler highs and lower humidities
as dewpoints fall into the 40s. Tues should also remain dry for
most of the day with rain expected to overspread the area Tues
night and last through Weds. Limited CAPE suggests only isolated
thunder but look for another widespread soaking rain out of this
system.
Perhaps a brief dry spell on Thursday before the next upper wave
approaches for late next week into next weekend. This system looks
very similar to this weekends so an active pattern will continue.
&&
.AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon)
Issued at 1234 PM CDT SAT MAY 16 2015
Sites have cleared to VFR after a line of showers moved through the
area this morning. VFR should continue until a line of storms moves
from SW to NE this afternoon into tonight impacting all terminals. Exact
timing and coverage of these storms is still uncertain, and have
continued to use VCTS for this reason. Storms will clear overnight
into tomorrow morning from W to E. After this clearing VFR will
prevail.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS PADUCAH KY
208 PM CDT SAT MAY 16 2015
.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 208 PM CDT SAT MAY 16 2015
WILL MAINTAIN CONVECTIVE CHANCES THROUGH MID TO LATE AFTERNOON.
OVERNIGHT EXPECT A DOWNWARD TREND IN COVERAGE...SO NO INCLUSION
FOR THE OVERNIGHT INTO THE MORNING SUNDAY. LOW CONFIDENCE IN BASE
HEIGHTS OVERNIGHT. GENERALLY STAYED MVFR THROUGH VARIABILITY IS
NOT OUT OF THE QUESTION. SOUTH WINDS TO PERSIST...WITH GUSTS 15-20
KTS DEVELOPING SUNDAY MORNING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
406 PM CDT SAT MAY 16 2015
SHORT TERM...NOT MUCH HAS CHANGED FROM 24 HOURS AGO. STILL IN QUITE
AN ACTIVE CONVECTIVE DAY WITH WIDESPREAD SHOWERS AND SCATTERED
THUNDERSTORMS IMPACTING THE CWA EXCEPT FOR AREAS SOUTH OF INTERSTATE
10. THINKING THAT SINCE THE ENVIRONMENT IS SO SIMILAR...ACTIVITY
MAINTAINABILITY WILL GO WELL INTO THE AFTERNOON AND EVENING HOURS
AGAIN. HRRR SHOWS STORMS GOING PAST MIDNIGHT EAST OF I-55. MAIN
THREAT WILL BE HEAVY RAIN AND POSSIBLE FLASH FLOODING AS SOME
TRAINING HAS BEEN OCCURRING. OTHERWISE...TYPICAL MARITIME ENVIORNMENT
IN PLACE POSES THE THREAT FOR WATERSPOUTS WHICH CAN ON OCCASION MOVE
ONSHORE.
SYNOPTICALLY SPEAKING...AN UPPER LEVEL TROUGH IS IN THE PROCESS OF
SWINGING ACROSS THE ROCKIES AND WILL REACH THE UPPER MISSISSIPPI
VALLEY BY LATE TOMORROW. THE WESTERN ATLANTIC AND EASTERN GULF OF
MEXICO WILL REMAIN UNDER AN UPPER RIDGE DURING THIS TIME. THE LOCAL
CWA BEING CAUGHT BETWEEN THESE 2 FEATURES WHICH WILL BE A FUNNEL
ZONE OF MOISTURE AND WEAK SHORTWAVES. DAYTIME POPS INTO TOMORROW
STILL AT ABOUT 50 PERCENT.
MEFFER
&&
.LONG TERM...A WEAK FRONTAL BOUNDARY WILL SAG INTO THE AREA GOING
INTO TUESDAY. A GENERAL WEAK SURFACE TROUGH WILL BE THE FOCUS FOR
ENHANCED CONVECTION THROUGH JUST ABOUT THE ENTIRE WEEK WITH AT LEAST
40 PERCENT FOR DAILY POPS. UPPER LEVEL RIDGE WILL TRY TO REASSERT
ITSELF OVER THE REGION LATE WEEK AND INTO THE WEEKEND WHICH WOULD
LOWER POPS AND INCREASE TEMPS. UPPER 80S TO NEAR 90 DEGREES COULD BE
COMING THEN.
MEFFER
&&
.AVIATION... SHOWERS AND THUNDERSTORMS WILL GENERALLY BE A POTENTIAL
IMPACT TO TERMINALS NORTH OF A KNEW TO KHUM LINE THROUGH THE NEXT
SEVERAL HOURS BEFORE STARTING TO WIND DOWN. IN ADDITION...STRONG
SOUTHEAST WINDS WILL RELAX QUITE A BIT ONCE THE SUN BEGINS TO SET.
VFR CONDITIONS EXPECTED ONCE THE CONVECTION WANES THIS EVENING. KGPT
AND KASD WILL BE THE LAST TO BE CONVECTION FREE AND THAT MAY NOT
HAPPEN UNTIL LATE TONIGHT.
MEFFER
&&
.MARINE...CURRENT WINDS OVER OFFSHORE WATERS ARE RIGHT AT OR JUST
ABOVE 15 KNOTS...SO REISSUING EXERCISE CAUTION THRU TONIGHT. CURRENT
SYNOPSIS SHOWS SURFACE RIDGE CENTERED JUST OFF THE CAROLINA COASTS
EXTENDS WELL INTO THE GULF OF MEXICO WHICH HAS ESTABLISHED ONSHORE
FLOW. THIS HIGH WILL SLOWLY WEAKEN AS IT SAGS SOUTH TOWARDS FLORIDA.
LOCAL WINDS WILL FOLLOW THIS WEAKENING TREND AS WELL...FALLING TO
LESS THAN 10 KNOTS ON TUESDAY. WEAK WIND FIELD WILL REMAIN IN PLACE
AS A COLD FRONT STALLS ALONG THE NORTHERN GULF COAST MID WEEK AND A
RAGGED SURFACE HIGH TRIES TO ESTABLISH ITSELF OVER THE GULF OF
MEXICO. COULD RETURN TO MORE CONSISTENT SOUTHEASTERLY WINDS NEXT
WEEKEND.
MEFFER
&&
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 71 85 71 85 / 40 50 20 60
BTR 73 87 73 87 / 40 50 20 60
ASD 74 85 73 86 / 40 40 20 50
MSY 75 86 75 86 / 40 40 20 50
GPT 75 84 75 84 / 50 40 20 30
PQL 73 84 73 84 / 50 40 10 40
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
121 PM EDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN
ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER
OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID
SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF
CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK
MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH
VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT
RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU
MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE
SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH
PLAINS OF S DAKOTA TO NEB.
BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER
MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER
LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY
CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH
TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF
SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR
EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT
RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND
NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA
OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY.
MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF
AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY
OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR
TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF
CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT
LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER
100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR
MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH
EDGE OF H85-H7 MOISTURE TRANSPORT.
EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT
WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE
ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE
CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS
WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS
NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS
NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF
FOG...LOCALLY DENSE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 520 AM EDT SAT MAY 16 2015
SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM
THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE
SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50
KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5
INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL
ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF
INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS
INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400-
800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z
MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE
COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE
ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND
THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S
WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY 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 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO
SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY
BE DRY OVERNIGHT.
MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW
ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON
BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT
COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS
ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY
END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC
FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD
-SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER
TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH
EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO
GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W-
NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST.
MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO
VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS
BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY
LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR
CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN.
DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES
FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON
ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE
LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR
SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND
PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE
VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY
FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED
THRU FRI...BUT REMAIN BLO NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 121 PM EDT SAT MAY 16 2015
TOUGH FORECAST TO FIGURE OUT WITH CONFIDENCE FAIRLY LOW. VFR
CONDITIONS WILL CONTINUE INTO THIS EVENING. UPSLOPE STRATUS AND FOG
COULD AFFECT BOTH CMX AND SAW TONIGHT WITH CMX GETTING IT FROM LAKE
SUPERIOR AND SAW GETTING IT WITH SOUTHEAST FLOW FROM LAKE MICHIGAN.
TOUGH TO TELL HOW LOW THE VISIBILITIES WILL GO AND WHAT HEIGHT IT
WILL BE...BUT WENT AHEAD AND WENT MVFR CONDITIONS FOR BOTH SITES
ANYWAY. IWD COULD GET THE SAME THING AND WENT MVFR CONDITIONS LATE
TONIGHT. THINK CMX WILL BE ABLE TO MIX OUT FOR SUN MORNING AND WENT
VFR FOR THEM. IWD AND SAW WILL HAVE A HARDER TIME MIXING OUT AND
KEPT THE LOW CLOUDS IN LONGER.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW
PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING
E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF
THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY
MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE
LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL
USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND
TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE
EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION
WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20
KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250.
&&
$$
SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
357 PM CDT SAT MAY 16 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 351 PM CDT SAT MAY 16 2015
WATER VAPOR IMAGERY THIS AFTERNOON INDICATES A STRONG UPPER LEVEL
CIRCULATION PUSHING EAST THROUGH NORTHERN NEW MEXICO...WITH
CONVECTIVE INITIATION IMMEDIATELY DOWNSTREAM OF THE WAVE ACROSS
THE TEXAS PANHANDLE. MEANWHILE...A WARM FRONT HAS LIFTED INTO
SOUTHERN MN AND DEW POINTS HAVE RISEN WELL INTO THE 60S.
ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS WESTERN MN INTO EASTERN
SD WILL CONTINUE AS DESTABILIZATION HAS OCCURRED. A SUBTLE WAVE
ADVANCING NORTH WILL HELP INITIATE STORM DEVELOPMENT IN THIS AREA.
EFFECTIVE BULK SHEAR VALUES OF AROUND 30-40 KNOTS MAY PRODUCE
MULTICELL CLUSTERS WITH ISOLATED EMBEDDED SUPERCELLS CAPABLE OF
PRODUCING ISOLATED SEVERE WEATHER ACROSS WESTERN MN THIS EVENING.
EASTERN MN AND WESTERN WI SHOULD GENERALLY REMAIN DRY THROUGH THE
EVENING...BEFORE SCATTERED SHOWERS AND WEAK THUNDERSTORMS MOVE IN
LATE TONIGHT THROUGH SUNDAY MORNING.
ON SUNDAY...THE AFOREMENTIONED UPPER LEVEL SHORTWAVE WILL ADVANCE
NORTH AND A DEEPENING SURFACE LOW WILL ADVANCE FROM KANSAS
NORTHWARD THROUGH NEBRASKA AND EVENTUALLY INTO EASTERN SOUTH
DAKOTA. WITH A MOIST AND UNSTABLE AIRMASS PRESENT...MUCH BETTER
SHEAR AND SURFACE ENERGY WILL COME TOGETHER THROUGH EARLY
AFTERNOON...ESPECIALLY ACROSS EASTERN MN AND WESTERN WI...WHERE
THE SEVERE WEATHER RISK HAS BEEN UPGRADED TO THE ENHANCED
CATEGORY. 0-6KM EFFECTIVE SHEAR APPROACHING 60 KNOTS COMBINED WITH
BETTER SURFACE HEATING ACROSS THIS AREA WILL ALLOW SURFACE BASED
CAPE VALUES OF 1000-2000 J/KG. CONFIDENCE IS RELATIVELY LOW THOUGH
IN THE SEVERE DEVELOPMENT POTENTIAL DUE TO MORNING CONVECTION AND
ITS POSSIBLE AFFECT ON DESTABILIZATION BY EARLY AFTERNOON. GIVEN
SUFFICIENT HEATING THOUGH...EXPECT BY EARLY AFTERNOON THE
POSSIBILITY OF DISCRETE SUPERCELL THUNDERSTORMS INITIATING IN
EASTERN MN AND WESTERN WI WHICH WOULD BE CAPABLE OF PRODUCING
SEVERE HAIL...WIND...AND A FEW TORNADOES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 351 PM CDT SAT MAY 16 2015
SFC LOW OVER N-CENTRAL MN WILL HAVE ITS PROGRESS SLOWED AS IT
RUNS INTO HIGHER PRES FROM THE N. MEANWHILE...THE DEEP UPR LVL LOW
WILL THEN RUN ATOP THE SFC LOW...MAKING FOR A DEEPLY STACKED LOW
PRES AREA CENTERED OVER NERN MN COME DAYBREAK MON MRNG. THE BULK
OF THE SHWRS/TSTMS WILL BE IN ERN PORTIONS OF THE WFO MPX CWFA BY
SUN EVE...PARTICULARLY ANYTHING OF A STRONG/SEVERE NATURE...
LEAVING MAINLY RESIDUAL SHOWERS AND ISOLD TSTMS IN THE WAKE OF THE
PASSING CDFNT. WHILE THE FRONTAL PRECIP COVERAGE WANES SUN NIGHT
INTO MON...THE DEEP COLD LOW MOVING OVER THE REGION MAY BRING
ADDITIONAL LIGHT RAIN SHOWERS TO NRN-CENTRAL MN AND NWRN WI DURG
THE DAY ON MON. THIS LOW WILL THEN PULL AWAY FROM THE AREA MON
NIGHT INTO TUE...BEING REPLACED BY SFC HIGH PRES THAT WILL REMAIN
IN PLACE TUE THRU FRI...MAKING FOR A PROLONGED DRY PERIOD FOR THE
REGION. HOWEVER...AT THE SAME TIME...THE NW-SE ORIENTATION OF THE
SFC HIGH COMBINED WITH A LONGWAVE TROF SETTING UP OVER ERN NOAM
WILL ALLOW A PERSISTENT PATH OF MUCH COLDER CANADIAN AIR TO TAKE
RESIDENCE OVER THE REGION THRU AT LEAST THE FIRST HALF OF THE
WEEK. THIS POTENT SURGE OF CAA WILL DROP TEMPS NEARLY 30 DEGREES
FROM SUN INTO MON AS HIGHS ON MON WILL RANGE FROM THE LOWER 40S TO
THE LOWER 50S. TEMPERATURES WILL THEN SLOWLY MODERATE THROUGH THE
REST OF THE WEEK...WITH HIGHS RETURNING TO THE UPPER 60S BY THE
END OF THE WEEK. FROST MAY BE A CONCERN ON MON AND TUE NIGHTS AS
LOWS DIP INTO THE LOW/MID 30S ACROSS PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM CDT SAT MAY 16 2015
CURRENT SCENARIO MAKES FOR A MESSY AVIATION FORECAST FOR THE AREA.
A SURFACE LOW IS PUSHING INTO WESTERN SOUTH DAKOTA FROM THE
WEST...WITH A WARM FRONT EXTENDING EAST AND DEW POINTS IN THE MID
60S SURGING NORTHWARD INTO SOUTHERN MN. DEW POINT DEPRESSIONS WILL
REMAIN JUST A COUPLE DEGREES...AND LOW LEVEL LCL`S SHOULD REMAIN
IN PLACE. SO...EXPECTING WIDESPREAD MVFR TO HOLD FOR THE MOST PART
WITH A FEW PERIODS OF SCATTERING OCCURRING THIS AFTERNOON. LATE
THIS AFTERNOON...A LINE OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AND PUSH EAST INTO WESTERN MN AND CONTINUE NORTHEAST THROUGH THE
EVENING. RWF/STC/AXN MAY ALL BE DIRECTLY IMPACTED BY THIS
LINE...BUT MSP MAY BE ON THE SOUTHERN PERIPHERY OF THESE
STORMS...WILL BE SOMETHING TO MONITOR. AS THE LOW DEEPENS IN SOUTH
DAKOTA TONIGHT AND TOMORROW MORNING...WE`LL REMAIN IN UNSTABLE AIR
AND MORE THUNDERSTORM DEVELOPMENT IS EXPECTED TOMORROW MORNING.
KMSP...BEST CHANCE FOR THUNDER TONIGHT WILL BE FROM 03Z TO
06Z...HOWEVER THE HRRR INDICATES THE POSSIBILITY THAT THE
THUNDERSTORM CLUSTER MOVING THROUGH WESTERN MN THIS AFTERNOON MAY
SLIDE JUST NORTH OF MSP...BUT IF IT DOES STILL EXPECT OTHER SPOTTY
THUNDERSTORM DEVELOPMENT LATE TONIGHT. FOR TOMORROW
AFTERNOON...STRONG THUNDERSTORMS LOOK TO DEVELOP AND MOVE THROUGH
FROM ROUGHLY 20-23Z.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS.
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...SPD
LONG TERM...JPC/CLF
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
104 PM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT SAT MAY 16 2015
VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST
THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT
CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION
THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE
ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE
CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS
NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE
MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME
SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH
THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT
MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS
SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE
RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE
AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL
LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD
OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE
ACROSS THE PLAINS AND INTO THE UPPER MIDWEST.
SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE
AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING
UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC
HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE
MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO
MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO
MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND
SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER
MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 406 AM CDT SAT MAY 16 2015
THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A
SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF
MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE
TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE
FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID
ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON.
THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW
PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS
MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE
AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER
LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE
COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM
WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES
APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON
SUNDAY AFTERNOON.
THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY
REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE
LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL
MN/WI THROUGH MONDAY.
BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS
AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL
CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO
ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH
FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE
60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY
NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS
PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM CDT SAT MAY 16 2015
CURRENT SCENARIO MAKES FOR A MESSY AVIATION FORECAST FOR THE AREA.
A SURFACE LOW IS PUSHING INTO WESTERN SOUTH DAKOTA FROM THE
WEST...WITH A WARM FRONT EXTENDING EAST AND DEW POINTS IN THE MID
60S SURGING NORTHWARD INTO SOUTHERN MN. DEW POINT DEPRESSIONS WILL
REMAIN JUST A COUPLE DEGREES...AND LOW LEVEL LCL`S SHOUDL REMAIN
IN PLACE. SO...EXPECTING WIDESPREAD MVFR TO HOLD FOR THE MOST PART
WITH A FEW PERIODS OF SCATTERING OCCURRING THIS AFTERNOON. LATE
THIS AFTERNOON...A LINE OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AND PUSH EAST INTO WESTERN MN AND CONTINUE NORTHEAST THROUGH THE
EVENING. RWF/STC/AXN MAY ALL BE DRIECTLY IMPACTED BY THIS
LINE...BUT MSP MAY BE ONTHE SOUTHERN PERIPHERY OF THESE
STORMS...WILL BE SOMETHING TO MONITOR. AS THE LOW DEEPENS IN SOUTH
DAKOTA TONIGHT AND TOMORROW MORNING...WE`LL REMAIN IN UNSTABLE AIR
AND MORE THUNDERSTORM DEVELOPMENT IS EXPECTED TOMORROW MORNING.
KMSP...BEST CHANCE FOR THUNDER TONIGHT WILL BE FROM 03Z TO
06Z...HOWEVER THE HRRR INDICATES THE POSSIBLITY THAT THE
THUNDERSTORM CLUSTER MOVING THROUGH WESTERN MN THIS AFTERNOON MAY
SLIDE JUST NORTH OF MSP...BUT IF IT DOES STILL EXPECT OTHER SPOTTY
THUNDERSTORM DEVELOPMENT LATE TONIGHT. FOR TOMORROW
AFTERNOON...STRONG THUNDERSTORMS LOOK TO DEVELOP AND MOVE THROUGH
FROM ROUGHLY 20-23Z.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS.
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...LS
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
333 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...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1230 PM CDT SAT MAY 16 2015
ALL THREE TAF SITES WERE VFR AS OF 17Z. A BAND OF SHOWERS AND
THUNDERSTORMS IS STILL EXPECTED TO DEVELOP ACROSS KANSAS AND MOVE
ACROSS ALL THREE TAF SITES THIS EVENING AND OVERNIGHT. ISOLATED
TSRA COULD DEVELOP ABOUT ANYTIME AROUND 21Z BUT EXPECTING THE
BETTER CHANCE OF ORGANIZED STORMS TO OCCUR AFTER 00Z. THIS IS
COVERED WITH TEMPO GROUPS IN ALL TAFS AND WILL LIKELY NEED TO BE
ADJUSTED ONCE ACTIVITY DEVELOPS. THUNDERSTORMS WILL MOVE NORTHEAST
LATE IN THE FORECAST PERIOD AND HAVE TRENDED THEM OUT OF KOMA AND
KLNK AFTER 14Z. DUE TO WRAP AROUND ACTIVITY AROUND DEEP SURFACE
LOW OVER EASTERN SOUTH DAKOTA BY 15Z...WILL KEEP THREAT OF -RA OR
EVEN -TSRA IN THE KOFK VICINITY THROUGH 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...MEYER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
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
&&
.AVIATION...
18Z TAF CYCLE
AN UPPER LEVEL TROUGH WILL SWING ACROSS NM THIS AFTERNOON. A
SURFACE COLD FRONT WILL ACCOMPANY THE TROUGH. PLENTY OF LOW LEVEL
MOISTURE AND AN UNSTABLE ATMOSPHERE WILL PRODUCE SHOWERS AND
THUNDERSTORMS THROUGH AT LEAST 03Z. A FEW STORMS OVER THE NE
COULD BE STRONG TO SEVERE THIS PM. BRIEF MVFR TO IFR CONDITIONS
LIKELY WITH ANY STORM. WET SNOW WILL FALL IN THE MTS WITH
OBSCURATIONS. WIND GUSTS APPROACHING 50 KT WITH THE STRONGEST
STORMS. OTHERWISE...MOSTLY VFR CONDITIONS. AREAS OF FOG WILL
DEVELOP LATE TONIGHT...ESPECIALLY OVER WRN AND CENTRAL NM WHERE
WINDS WILL BE LOWEST. FOR NOW HAVE VCFG IN MANY OF THE TAF SITES.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 37 68 42 77 / 20 0 0 10
DULCE........................... 30 64 35 69 / 40 5 5 20
CUBA............................ 32 64 38 69 / 30 5 5 10
GALLUP.......................... 29 66 35 76 / 20 0 0 10
EL MORRO........................ 28 63 33 69 / 20 0 0 10
GRANTS.......................... 30 67 32 74 / 20 0 0 10
QUEMADO......................... 32 64 34 71 / 10 0 0 5
GLENWOOD........................ 37 72 43 80 / 5 0 0 5
CHAMA........................... 27 59 30 63 / 60 10 10 20
LOS ALAMOS...................... 37 61 44 66 / 30 5 5 10
PECOS........................... 35 62 39 64 / 20 5 5 10
CERRO/QUESTA.................... 29 63 33 64 / 50 10 10 20
RED RIVER....................... 27 53 32 56 / 60 10 10 40
ANGEL FIRE...................... 26 58 30 59 / 50 10 5 30
TAOS............................ 27 64 35 67 / 30 5 5 20
MORA............................ 34 62 38 61 / 30 0 5 20
ESPANOLA........................ 38 68 42 71 / 20 5 5 10
SANTA FE........................ 38 62 44 66 / 20 5 5 10
SANTA FE AIRPORT................ 36 67 40 71 / 20 5 5 10
ALBUQUERQUE FOOTHILLS........... 39 68 43 73 / 20 0 0 10
ALBUQUERQUE HEIGHTS............. 44 70 49 76 / 10 0 0 5
ALBUQUERQUE VALLEY.............. 39 72 46 80 / 10 0 0 5
ALBUQUERQUE WEST MESA........... 43 71 48 77 / 20 0 0 5
LOS LUNAS....................... 39 71 44 78 / 10 0 0 5
RIO RANCHO...................... 42 70 48 76 / 20 0 0 5
SOCORRO......................... 43 74 47 81 / 10 0 0 5
SANDIA PARK/CEDAR CREST......... 38 64 44 70 / 20 0 0 10
TIJERAS......................... 37 68 40 73 / 20 0 0 10
MORIARTY/ESTANCIA............... 32 66 32 70 / 10 0 0 10
CLINES CORNERS.................. 34 65 39 67 / 10 0 0 10
GRAN QUIVIRA.................... 36 66 38 71 / 10 0 0 10
CARRIZOZO....................... 41 69 44 76 / 5 0 0 10
RUIDOSO......................... 40 65 46 72 / 5 0 0 10
CAPULIN......................... 35 67 40 63 / 30 0 10 20
RATON........................... 36 72 41 68 / 30 0 10 30
SPRINGER........................ 38 72 42 68 / 30 0 5 20
LAS VEGAS....................... 36 66 37 65 / 20 0 0 20
CLAYTON......................... 45 76 47 70 / 30 0 5 20
ROY............................. 42 71 45 67 / 20 0 5 20
CONCHAS......................... 47 77 49 75 / 10 0 5 10
SANTA ROSA...................... 45 75 47 76 / 5 0 0 10
TUCUMCARI....................... 48 80 49 78 / 5 0 5 10
CLOVIS.......................... 46 77 48 78 / 5 0 10 10
PORTALES........................ 47 77 49 79 / 5 0 10 10
FORT SUMNER..................... 46 77 48 79 / 5 0 5 10
ROSWELL......................... 48 80 50 84 / 5 0 5 10
PICACHO......................... 44 74 47 76 / 5 0 0 10
ELK............................. 41 69 46 72 / 5 0 5 10
&&
.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
339 PM CDT SAT MAY 16 2015
.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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 340 PM CDT SAT MAY 16 2015
AT 230 PM CDT A WARM FRONT EXTENDED FROM A SURFACE LOW PRESSURE
CENTERED OVER NORTHWEST SOUTH DAKOTA WITH AN EAST WEST WARM FRONT
EXTENDING EAST ACROSS NORTH CENTRAL SOUTH DAKOTA. MOIST FLOW OVER
THE FRONT WILL MAINTAIN WIDESPREAD IFR KISN- KDIK-KBIS-KMOT WITH
MVFR CONDITIONS KJMS. THUNDERSTORMS WILL BECOME MORE NUMEROUS
LATE SATURDAY AFTERNOON AND EVENING EAST OF KBIS- KMOT LINE.
&&
.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.
&&
$$
SHORT TERM...WAA
LONG TERM...AJ
AVIATION...WAA
HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1248 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1239 PM CDT SAT MAY 16 2015
LAUNCHED AN 18Z SOUNDING IN SUPPORT OF THE SEVERE WEATHER
OPERATIONS THIS AFTERNOON AND EVENING. AT 1230 CDT A WARM FRONT
EXTENDED FROM A LOW IN SOUTHEAST MONTANA EAST THROUGH NORTH
CENTRAL SOUTH DAKOTA. FOCUSED THE HIGHEST POPS WEST CENTRAL INTO
THE NORTH WHERE BEST OVER RUNNING FLOW OVER THE WARM FRONT
CURRENTLY IS SPAWNING SHOWERS AND A FEW THUNDERSTORMS. RIGHT NOW
THE ACTIVITY IS ELEVATED WAND WEAK. WILL BE ANTICIPATING FURTHER
DEVELOPMENT NEXT FEW HOURS INTO THE EVENING CENTRAL MOVING INTO
THE JAMES RIVER VALLEY THIS EVENING.
UPDATE ISSUED AT 923 AM CDT SAT MAY 16 2015
VERY MOIST BOUNDARY LAYER AFTER OVERNIGHT RAINS. ACROSS THE SOUTHWEST
A SOUTHEAST UPSLOPE FLOW HAS RESULTED IN AREAS OF FOG AND LOW
CLOUDS. WILL ADD THIS TO THE FOREST THROUGH NOON. ELEVATED
CONVECTION ONGOING OVER THE LOW LEVELS SOUTHWEST SO KEPT A SLIGHT
CHANCE OF THUNDERSTORMS THERE. HOWEVER...DROPPED THE MENTION OF
THUNDERSTORMS THIS MORNING NORTH AND EAST BASED ON LATEST HRRR
CAPE FORECAST WHICH BASICALLY HOLDS OF THE THREAT OF THUNDER TIL
THIS AFTERNOON.
UPDATE ISSUED AT 615 AM CDT SAT MAY 16 2015
AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM
DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH
CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE
NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN
RAPID CITY AND ABERDEEN SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUD COVER DAYBREAK TEMPERATURES MONDAY MORNING WILL
BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY
MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE
STRONG NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1239 PM CDT SAT MAY 16 2015
AT 1230 PM CDT A WARM FRONT EXTENDED FROM A SURFACE LOW PRESSURE
CENTERED OVER SOUTHEAST MONTANA WITH A WARM FRONT EXTENDING EAST
ACROSS NORTH CENTRAL SOUTH DAKOTA. MOIST FLOW OVER THE FRONT WILL
MAINTAIN WIDESPREAD IFR KISN- KDIK-KBIS WITH MVFR CONDITIONS
KMOT- KJMS. CONDITIONS GENERALLY BECOMING MVFR LATE SATURDAY
AFTERNOON. THUNDERSTORMS WILL BECOME MORE NUMEROUS LATE SATURDAY
AFTERNOON AND EVENING EAST OF KBIS-KMOT LINE.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE 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...WAA
SHORT TERM...JV
LONG TERM...JPM
AVIATION...WAA
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
237 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/...
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 /18Z SATURDAY THROUGH THURSDAY/...
HIGHLY VARIABLE CONDITIONS IN ROUNDS OF SHOWERS AND THUNDERSTORMS.
THINKING THE CONVECTION MOST WIDESPREAD IN THE WESTERN LOWLANDS
INCLUDING SOUTHEAST OHIO AND NORTHEAST KENTUCKY. HAVE ONE LOBE OF
CONVECTION LIFTING NNE THROUGH THOSE COUNTIES 19Z TODAY TO 00Z
SUNDAY.
MORE SHOWERS WITH EMBEDDED THUNDERSTORMS COULD EASILY FORM OVERNIGHT
EVEN 06Z TO 12Z.
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 18Z SUNDAY...
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.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H M M M M M M
HTS CONSISTENCY H M M M M M M M M M M M
BKW CONSISTENCY H H H H M H M M M M M H
EKN CONSISTENCY H H H H H M M M M M M M
PKB CONSISTENCY H H H H M M M M M M M M
CKB CONSISTENCY M H H H H H M M M M M M
AFTER 18Z SUNDAY...
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...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
142 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL AFFECT THE REGION
THIS WEEKEND. A COLD FRONT WILL APPROACH ON MONDAY...MOVING
THROUGH BY EARLY TUESDAY. HIGH PRESSURE BUILDS IN DURING THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRECIPITATION HAS SLOWLY BEGUN TO INCREASE IN COVERAGE OVER THE
PAST FEW HOURS...AND THIS TREND IS GENERALLY EXPECTED TO CONTINUE
THROUGH EARLY TO MID AFTERNOON. AN ANALYSIS OF LOW-LEVEL WINDS
INDICATES PERSISTENT SOUTHWESTERLY FLOW...BRINGING A CONTINUED
TRANSPORT OF MOISTURE DIRECTLY INTO THE OHIO VALLEY. THERE IS
CONVERGENCE AHEAD OF THIS MOISTURE ADVECTION...AND AS WEAK
INSTABILITY BUILDS...THE COVERAGE AND INTENSITY SHOULD INCREASE AS
WELL. POPS HAVE BEEN REFINED SLIGHTLY BUT REMAIN AT THE HIGH
CHANCE TO LIKELY LEVELS ACROSS THE FORECAST AREA (PRIMARILY AROUND
18Z-21Z). IF THE HRRR VERIFIES...PRECIPITATION MAY END UP EVEN
MORE WIDESPREAD...AND FUTURE UPDATES MAY NEED TO INCREASE THE
PRECIPITATION CHANCES EVEN FURTHER.
THE 12Z KILN SOUNDING IS VERY MOIST (PWAT OF 1.42 INCHES) WITH
POOR LAPSE RATES THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE.
THIS WILL LIMIT INSTABILITY TODAY...WITH A NARROW PROFILE OF CAPE
THAT MAY GET TO AROUND 1000 J/KG AT MOST. WITH WEAK SHEAR...STORM
ORGANIZATION SHOULD NOT BE MUCH TO SPEAK OF...AND THUS THE THREAT
FOR STRONG STORMS APPEARS LOW.
TEMPERATURES WERE ADJUSTED JUST SLIGHTLY DOWNWARD...WITH
CONFIDENCE IN CLOUDS AND PRECIPITATION (AND A MOIST BOUNDARY
LAYER) LIMITING HEATING POTENTIAL.
PREVIOUS DISCUSSION >
A FEW SHOWERS CONTINUE TO AFFECT WESTERN/CENTRAL OHIO AT 07Z. THIS
ACTIVITY WILL CONTINUE TO MOVE NORTH-NORTHEAST OVER THE NEXT FEW
HOURS...LIKELY DISSIPATING BY SUNRISE.
RIDGE AXIS HAS SHIFTED A LITTLE EAST OF THE OHIO
VALLEY EARLY THIS MORNING...RESULTING IN A BROAD SOUTHWEST FLOW
ALOFT. WEAK VORT MAXES EMBEDDED WITHIN THIS FLOW WILL CONTINUE TO
SUPPORT PERIODS OF CONVECTIVE ACTIVITY THROUGH THE DAY. IT LOOKS
LIKE THE NEXT ROUND OF CONVECTION WILL LIKELY OCCUR IN NORTHERN
KENTUCKY/SOUTHWEST OHIO BY 10-11Z...MOVING NORTHEAST DURING THE
MORNING. THEN AN ADDITIONAL UPTICK IN CONVECTION WILL LIKELY OCCUR
FOR THE MIDDAY/AFTERNOON GIVEN INCREASING PRECIPITABLE WATER
VALUES /POSSIBLY AROUND 1.7 INCHES BY AFTERNOON/...AFTERNOON
INSTABILITY AND THE LIKELIHOOD OF ANOTHER VORT MAX PROMOTING LIFT.
WENT WITH HIGH CHANCE TO LOW END LIKELY POPS ACROSS THE CWA DURING
THIS TIME.
GIVEN RELATIVE WEAK INSTABILITY /MOST GUIDANCE SUGGESTING CAPE
LESS THAN 1000 J/KG/ AND SHEAR...SEVERE WEATHER IS NOT EXPECTED.
HOWEVER CAN/T RULE OUT A LOCALLY STRONG STORM WITH GUSTY WINDS AND
ALSO GIVEN HIGHER MOISTURE CONTENT LOCALLY HEAVY DOWNPOURS MAY
RESULT.
USED A BLEND OF BIAS CORRECTED MET/MAV FOR HIGH TEMPERATURES
TODAY...FAVORING UPPER 70S/AROUND 80 ACROSS MUCH OF THE CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
WHILE COVERAGE OF CONVECTION FROM THE AFTERNOON/EARLY EVENING
SHOULD WANE OVERNIGHT...WILL CONTINUE WITH LOW CHANCE POPS ACROSS
THE CWA AS ATMOSPHERE WILL REMAIN WARM/MOIST AND ANY VORT MAX MAY
KEEP SOME CONVECTION GOING INTO THE NIGHT.
SIMILAR SITUATION IS EXPECTED ON SUNDAY...WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGHOUT THE DAY BUT THE HIGHEST COVERAGE TO
FAVOR THE AFTERNOON. A COLD FRONT IS THEN EXPECTED TO APPROACH ON
MONDAY. WIND FIELDS MAY BE A LITTLE BETTER AND COULD PROMOTE SOME
DEGREE OF ORGANIZATION TO THUNDERSTORMS. CONFIDENCE IS LOW HOWEVER
AND WILL LEAVE MENTION OF STRONG/SEVERE STORMS OUT OF THE HWO
ATTM. MONDAY WILL FEATURE ONE MORE WARM/MUGGY DAY BEFORE CHANGES
OCCUR BEHIND THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL THEN MOVE THROUGH THE AREA LATE MONDAY NIGHT AND
TUESDAY MORNING WITH DRIER AND COOLER AIR MOVING IN BEHIND.
MODELS HAVE SLOWED THE FRONT DOWN A BIT AND GIVEN CURRENT
FORECASTED UPPER LEVEL FLOW THIS MAKES SENSE. THE UPPER LEVEL LOW
JUST NORTH OF WISCONSIN MONDAY WASHES OUT WITH A SECONDARY
SHORTWAVE MOVING SOUTH TUESDAY INTO WEDNESDAY. FORECASTED 850
TEMPERATURES FOR NEXT WEEK (5 - 10 DEGREES C) ALSO DON`T LOOK AS
COOL AS THEY WERE OVER THE LAST COUPLE OF DAYS. HAVE TRENDED HIGH
TEMPERATURES UP TOWARDS 70 A BIT TO ACCOUNT FOR THIS. BELOW NORMAL
TEMPERATURES WILL THEN CONTINUE THROUGH THE END OF THE NEXT WORK
WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
ALTHOUGH SCATTERED SHOWERS HAVE BEEN AROUND THE TAF SITES ALL
MORNING...A MORE STEADY AREA OF RAIN (WITH EMBEDDED CONVECTION) IS
NOW MOVING INTO THE CINCINNATI AIRPORTS...AND WILL SPREAD NORTH TO
DAYTON AND COLUMBUS IN THE NEXT COUPLE HOURS. PREVAILING MVFR
CONDITIONS ARE EXPECTED...THOUGH A HEAVY DOWNPOUR COULD BRING
BRIEF IFR CONDITIONS. THUNDER REMAINS A POSSIBILITY...BUT FOR THE
MOST PART THERE HAS NOT BEEN AN ABUNDANCE OF LIGHTNING OBSERVED IN
THE CURRENT PRECIPITATION...SO THIS HAS NOT BEEN INCLUDED
SPECIFICALLY IN THE TAFS.
RAIN IS EXPECTED TO BECOME MORE SCATTERED THIS EVENING AND INTO
THE OVERNIGHT. HOWEVER...MVFR CEILINGS ARE EXPECTED TO REMAIN IN
PLACE.
THERE IS THE POTENTIAL FOR ADDITIONAL SHOWER AND THUNDERSTORM
DEVELOPMENT LATE IN THE TAF PERIOD...BOTH EARLY SUNDAY MORNING AS
WELL AS SUNDAY AFTERNOON. THE EXACT TIMING AND INTENSITY OF THIS
POTENTIAL DEVELOPMENT IS UNCERTAIN...SO A VCSH WILL BE USED
THROUGHOUT THE REST OF THE TAF PERIOD.
WINDS THROUGH THE TAF PERIOD WILL BE OUT OF THE SSW...GENERALLY AT
AROUND 10 KNOTS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE AT TIMES ON SUNDAY AND
MONDAY. MVFR CEILINGS MAY ALSO OCCUR AT TIMES ON SUNDAY AND MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BPP
NEAR TERM...HATZOS/BPP
SHORT TERM...BPP
LONG TERM...HAINES
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1250 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1059 AM CDT SAT MAY 16 2015
MESSY DAY AHEAD AS A SMALL MCS EXITS TO THE NORTH LEAVING BEHIND
EASTERLY FLOW IN THE FAR NORTHERN CWA. JET MAX LIFTING NORTH OVER
THE WESTERN HIGH PLAINS WILL SWING THROUGH THE ENTRANCE REGION
THIS AFTERNOON AND SOME EFFECTS OF THAT MAY ALREADY BE SHOWING UP.
A SMALL POSSIBLE MCV IS LIFTING NORTH INTO NORTH CENTRAL NEBRASKA
AND WILL LIFT THROUGH THE CWA EARLY THIS AFTERNOON. A HANDFUL OF
THE HIGH RESOLUTION MODELS INDICATING SCATTERED THUNDERSTORMS
POSSIBLE BETWEEN ABOUT THE JAMES RIVER AND INTERSTATE 29 AND
SUSPECT IT IS ASSOCIATED WITH THIS FEATURE. NOT SURE HOW MUCH TO
REALLY BITE ON THIS RIGHT NOW. IF THESE STORMS CAN DEVELOP AN
ISOLATED SEVERE STORM WOULD BE POSSIBLE BUT WITH CAPE VALUES
FAIRLY LOW...AROUND 1000 J/KG...MAINLY LOOKING AT QUARTERS AND 60
MPH WINDS.
IF THIS SMALL MCV FEATURE DOES NOT SET ANY ACTIVITY OFF THE FLOW
IS NOT REALLY CONVERGENT AT ALL AND WOULD 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.
WILL PROBABLY DECREASE POPS A BIT THIS AFTERNOON AND FOCUS BEST
CHANCES AFTER ABOUT 2-4Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM CDT SAT MAY 16 2015
MVFR CEILINGS WILL LIFT NORTH THROUGH THE AFTERNOON...BUT MAY
AGAIN REDEVELOP AFTER SUNSET AS MIXING DECREASES AND THE INVERSION
STRENGTHENS AGAIN. BACKED OFF ON THUNDERSTORM CHANCES THIS
AFTERNOON AND EVENING BUT WILL STILL BRING A GOOD CHANCES FOR
THUNDERSTORMS THROUGH FROM ABOUT 4Z THROUGH 12Z. AT THIS TIME NOT
EXPECTING MORE THAN ISOLATED SEVERE STORMS BUT THERE COULD BE
QUITE A FEW STORMS CAPABLE OF LIGHTNING...SMALL HAIL AND HEAVY
RAINFALL.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...08
SHORT TERM...
LONG TERM...
AVIATION...08
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1241 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1159 AM CDT SAT MAY 16 2015
MUCH UNCERTAINTY OVER SEVERE WEATHER POTENTIAL THIS AFTERNOON
THANKS MAINLY TO CLOUD COVER. WARM FRONT CONTINUES TO SLOWLY LIFT
ACROSS THE CWA...PROVIDING A NARROW RIBBON OF FAVORABLE SEVERE
WEATHER PARAMETERS...AND AS A FOCUS FOR AROUND 1000 J/KG CAPE.
HOWEVER HRRR AND NSSL WRF TEND TO GENERATE SPOTTY CONVECTION
ACROSS THE CWA IN THE AFTERNOON/EVENING...WHICH MAY BE AN
ARTIFACT OF THE WEAK UPPER SUPPORT AND INHIBITION FROM CLOUD
COVER. DESPITE THESE RESERVATIONS...LOW LEVEL SHEAR AND LOW LCLS
SUPPORT CONTINUED MONITORING FOR A SEVERE WEATHER THREAT AND
MENTION IN ZONE. THE MAIN SHORTWAVE LIFTING NORTH TOWARDS SUNDAY
AM IS ASSOCIATED WITH THE BEST JET DYNAMICS...AND SREF
PROBABILITIES FOR HEAVY RAIN ARE QUITE HIGH.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1231 PM CDT SAT MAY 16 2015
MAINLY VFR OR PERHAPS OCCASIONALLY MVFR CONDITIONS ON
SOUTH/SOUTHEASTERLY WINDS WILL BE THE RULE OVER THE NEXT 12 HOURS
AT LEAST. ANY CONVECTION WILL LIKELY KNOCK THAT DOWN INTO IFR
RANGE DUE TO VISBY/CIG RESTRAINTS IN HEAVIER DOWNPOURS. CONVECTION
TODAY/TONIGHT WILL HAVE THE ABILITY TO PRODUCE LARGE
HAIL...DAMAGING WINDS AND PERHAPS EVEN A BRIEF TORNADO. LATER
TONIGHT INTO SUNDAY...STRONG NORTH/NORTHWEST WINDS WILL DEVELOP
OVER THE KPIR AND KMBG TERMINALS WHILE A BROAD BAND OF MODERATE TO
OCCASIONALLY HEAVY RAIN SHOWERS AND EMBEDDED THUNDER LIFTS UP
ACROSS THE REGION...LIKELY AFFECTING ALL FOUR TERMINALS AT SOME
POINT HEADING INTO SUNDAY MORNING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...DORN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1224 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1159 AM CDT SAT MAY 16 2015
MUCH UNCERTAINTY OVER SEVERE WEATHER POTENTIAL THIS AFTERNOON
THANKS MAINLY TO CLOUD COVER. WARM FRONT CONTINUES TO SLOWLY LIFT
ACROSS THE CWA...PROVIDING A NARROW RIBBON OF FAVORABLE SEVERE
WEATHER PARAMETERS...AND AS A FOCUS FOR AROUND 1000 J/KG CAPE.
HOWEVER HRRR AND NSSL WRF TEND TO GENERATE SPOTTY CONVECTION
ACROSS THE CWA IN THE AFTERNOON/EVENING...WHICH MAY BE AN
ARTIFACT OF THE WEAK UPPER SUPPORT AND INHIBITION FROM CLOUD
COVER. DESPITE THESE RESERVATIONS...LOW LEVEL SHEAR AND LOW LCLS
SUPPORT CONTINUED MONITORING FOR A SEVERE WEATHER THREAT AND
MENTION IN ZONE. THE MAIN SHORTWAVE LIFTING NORTH TOWARDS SUNDAY
AM IS ASSOCIATED WITH THE BEST JET DYNAMICS...AND SREF
PROBABILITIES FOR HEAVY RAIN ARE QUITE HIGH.
UPDATE ISSUED AT 647 AM CDT SAT MAY 16 2015
AVIATION DISCUSSION UPDATED BELOW FOR 12Z TAFS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 647 AM CDT SAT MAY 16 2015
QUITE A VARIATION OF CONDITIONS THROUGH THE TAF FORECAST PERIOD.
THIS MORNING...A MIX OF CIGS ACROSS THE REGION RANGING FROM AROUND
500 FT TO LOW END VFR CONDITIONS. ALSO SEEING SHRA AFFECTING KABR
AND KATY BUT WILL BE ENDING BY 13Z. EXPECTING REDEVELOPMENT OF
SHOWER AND STORM ACTIVITY BY AROUND 18Z AND PERSISTING THROUGH THE
AFTERNOON ACROSS MUCH OF THE FORECAST AREA. HEAVIER STORMS MAY
DROP CIGS INTO MVFR AND VSBY INTO IFR. SEVERE STORMS ARE POSSIBLE
AS WELL AND COULD AFFECT TERMINALS WITH GUSTY SFC WINDS AND HAIL.
LATE T0NIGHT...ANOTHER BATCH OF RAINFALL IS EXPECTED TO MOVE
NORTHWARD INTO THE REGION.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1115 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1059 AM CDT SAT MAY 16 2015
MESSY DAY AHEAD AS A SMALL MCS EXITS TO THE NORTH LEAVING BEHIND
EASTERLY FLOW IN THE FAR NORTHERN CWA. JET MAX LIFTING NORTH OVER
THE WESTERN HIGH PLAINS WILL SWING THROUGH THE ENTRANCE REGION
THIS AFTERNOON AND SOME EFFECTS OF THAT MAY ALREADY BE SHOWING UP.
A SMALL POSSIBLE MCV IS LIFTING NORTH INTO NORTH CENTRAL NEBRASKA
AND WILL LIFT THROUGH THE CWA EARLY THIS AFTERNOON. A HANDFUL OF
THE HIGH RESOLUTION MODELS INDICATING SCATTERED THUNDERSTORMS
POSSIBLE BETWEEN ABOUT THE JAMES RIVER AND INTERSTATE 29 AND
SUSPECT IT IS ASSOCIATED WITH THIS FEATURE. NOT SURE HOW MUCH TO
REALLY BITE ON THIS RIGHT NOW. IF THESE STORMS CAN DEVELOP AN
ISOLATED SEVERE STORM WOULD BE POSSIBLE BUT WITH CAPE VALUES
FAIRLY LOW...AROUND 1000 J/KG...MAINLY LOOKING AT QUARTERS AND 60
MPH WINDS.
IF THIS SMALL MCV FEATURE DOES NOT SET ANY ACTIVITY OFF THE FLOW
IS NOT REALLY CONVERGENT AT ALL AND WOULD 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.
WILL PROBABLY DECREASE POPS A BIT THIS AFTERNOON AND FOCUS BEST
CHANCES AFTER ABOUT 2-4Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 638 AM CDT SAT MAY 16 2015
BROAD AREA OF MVFR AND IFR CONDITIONS ACROSS THE FORECAST AREA
THIS MORNING IN ADDITION TO SCATTERED TSRA TRACKING NORTHEAST
THROUGH THE REGION. EXPECT THIS ACTIVITY TO CONTINUE TO WEAKEN AND
DIMINISH THROUGH 15Z. MODELS SUGGEST THAT SOME IMPROVEMENT TO
CEILINGS FROM SOUTH TO NORTH THROUGH MIDDAY. ADDITIONAL SHOWER AND
THUNDERSTORMS DEVELOPMENT IS EXPECTED IN THE AFTERNOON...BECOMING
MORE WIDESPREAD BY EVENING. TIMING IS A BIT DIFFICULT AT THIS
POINT...BUT HAVE ADDED TSRA MENTION AND LOWER CEILINGS TO TAF
SITES THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...08
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
311 PM CDT SAT MAY 16 2015
.DISCUSSION...
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...
18Z TAFS
WIDESPREAD MVFR CIGS ACROSS THE MIDSOUTH THIS MORNING WILL
GRADUALLY LIFT TO VFR THIS AFTERNOON. SCATTERED SHRA AND TSRAS
EXPECTED ACROSS THE REGION AND WILL CONTINUE VCTS AT ALL TERMINALS
THROUGH EARLY EVENING. COVERAGE WILL DIMINISH WILL LOSS OF
HEATING THIS EVENING. 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.
SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER GUSTS
THIS AFTERNOON AT MEM AND KJBR.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
102 PM CDT SAT MAY 16 2015
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 1049 AM CDT SAT MAY 16 2015/
UPDATE...
AN AREA OF SHOWERS CONTINUE TO MOVE NORTH OVER PORTIONS OF WEST
TENNESSEE...NORTHEAST ARKANSAS...AND THE MISSOURI BOOTHEEL. THIS
AREA SHOULD MOVE INTO KENTUCKY AND MISSOURI BETWEEN 12-1 PM.
MEANWHILE...DRY CONDITIONS ARE CURRENTLY OCCURRING OVER NORTH
MISSISSIPPI. THE LATEST HRRR SHOWS ADDITIONAL DEVELOPMENT
OCCURRING ACROSS SOUTHERN MISSISSIPPI THAT WILL MOVE INTO NORTH
MISSISSIPPI AROUND 2 PM. THE CONVECTION WILL EVENTUALLY SPREAD
INTO THE REST OF THE MIDSOUTH BETWEEN 3-5 PM. FORECAST LOOKS
GOOD...NO UPDATES ARE EXPECTED.
KRM
DISCUSSION... /ISSUED 430 AM CDT SAT MAY 16 2015/
A WET DAY IS IN STORE FOR THE MIDSOUTH TODAY...FINALLY SEEMS MORE
LIKE MAY ACROSS THE MIDSOUTH THAN WHAT WE HAVE EXPERIENCED THROUGH
MUCH OF THE FIRST HALF OF THE MONTH. AREAS OF RAIN AND A FEW
THUNDERSTORMS WERE ALREADY OCCURRING ACROSS THE MIDSOUTH EARLY THIS
MORNING. THE WET PATTERN WILL CONTINUE INTO MONDAY AND WILL NEED TO
MONITOR FOR THE POSSIBILITY OF FLOODING / FLASH FLOODING AS RAINFALL
AMOUNTS INCREASE OVER TIME THROUGH THE WEEKEND INTO MONDAY.
A LARGE UPPER LEVEL LOW WAS LOCATED OVER THE WESTERN UNITED
STATES WITH AN UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST. A
SOUTHERLY WIND FLOW BETWEEN THESE TWO SYSTEMS WAS PUSHING ABUNDANT
MOISTURE INTO THE MIDSOUTH FROM THE GULF OF MEXICO. AN UPPER LEVEL
SHORT WAVE WAS LOCATED OVER EAST TX AND WILL MOVE NORTHEASTWARD
THROUGH THE MIDSOUTH TODAY. OCCASIONAL SHOWERS AND SCATTERED
THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY. PRECIPITABLE
WATER VALUES WILL BE BETWEEN 1.8 AND 2.0 INCHES WITH SURFACE DEW
POINTS IN THE MIDDLE 60S TO NEAR 70 DEGREES. AS A RESULT...LOCALLY
HEAVY RAINFALL MAY RESULT IN FLOODING IN SOME LOCATIONS TODAY...BUT
NOT CONFIDENT ENOUGH THAT WILL BE WIDESPREAD ENOUGH FOR A FLASH FLOOD
WATCH ATTM. DID MENTION THE THREAT OF LOCALLY HEAVY RAINFALL
AND FLOODING IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. INSTABILITY
LOOKS TO BE A LITTLE LESS THAN YESTERDAY WITH MORE WIDESPREAD RAIN
AND CLOUDS.
FOR TONIGHT...AN UPPER LEVEL TROUGH MOVES INTO THE CENTRAL PLAINS
WITH AN ASSOCIATED COLD FRONT STRETCHING FROM KS INTO TX. ORGANIZED
CONVECTION IS EXPECTED TO DEVELOP AHEAD OF THIS FRONT THROUGH THE
PLAINS PERHAPS APPROACHING NORTHEAST ARKANSAS LATE TONIGHT...ALTHOUGH
INSTABILITY DECREASING BY THAT TIME. WEAK UPPER LEVEL DISTURBANCES
EMBEDDED IN SOUTHWEST FLOW ALOFT WILL CONTINUE THE THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT ACROSS THE MIDSOUTH.
SUNDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR
WITH LOCALLY HEAVY RAINFALL A CONTINUING THREAT. THE UPPER LEVEL
TROUGH WILL PUSH TO THE NORTHEAST THROUGH THE CENTRAL PLAINS WITH
THE ASSOCIATED COLD FRONT REMAINING TO OUR WEST AND NORTH. THE
GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE TO OUR NORTH. 0-6
KM BULK SHEAR VALUES ARE ONLY MARGINAL FOR ORGANIZED SHEAR WEATHER
NEAR EXTREME NORTHEAST ARKANSAS AND THE MO BOOTHEEL. HOWEVER...
WIND FIELDS WILL BE STRONGER ACROSS THE MIDSOUTH SUNDAY AS THE UPPER
LEVEL TROUGH MOVES TO OUR NORTH. THIS WILL ALLOW WARMER SURFACE
TEMPERATURES TO PUSH INTO THE MIDSOUTH CAUSING GREATER INSTABILITY
AND THE POSSIBILITY A FEW STRONG TO SEVERE THUNDERSTORMS. IF ANY
SEVERE THUNDERSTORMS DO DEVELOP...DAMAGING WIND AND LARGE HAIL
WOULD BE THE GREATEST SEVERE WEATHER THREATS.
A COLD FRONT WILL SAG INTO THE MIDSOUTH FROM THE NORTH MONDAY AS THE
UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST WEAKENS SOME WITH
LOWERING UPPER LEVEL HEIGHTS ACROSS THE MIDSOUTH. WILL ONCE AGAIN
NEED TO MONITOR FOR HEAVY RAINFALL AND FLOODING / FLASH FLOODING.
THE COLD FRONT WILL GRADUALLY PUSH THROUGH THE MIDSOUTH MONDAY NIGHT
AND TUESDAY WITH DECREASING CHANCES FOR RAIN FROM THE NORTH.
TEMPERATURES WILL BE A LITTLE COOLER WITH PASSAGE OF THE COLD FRONT.
FOR THE REMAINDER OF THE WORK WEEK...THE ECMWF AND GFS ARE NOT IN
VERY GOOD AGREEMENT ON HOW FAR SOUTH THE COLD FRONT PUSHES AND HOW
QUICKLY IT PUSHES BACK NORTH. NEVERTHELESS...THE MODELS DO INDICATE
A CHANCE OF SHOWERS...PERHAPS THUNDERSTORMS...WILL MOVE BACK INTO
THE REGION FROM THE WEST. THE ECMWF IS FASTER BRINGING THE THREAT
OF SHOWERS AND THUNDERSTORMS BACK INTO THE REGION AS QUICKLY AS
WEDNESDAY.
JCL
&&
.AVIATION...
18Z TAFS
WIDESPREAD MVFR CIGS ACROSS THE MIDSOUTH THIS MORNING WILL
GRADUALLY LIFT TO VFR THIS AFTERNOON. SCATTERED SHRA AND TSRAS
EXPECTED ACROSS THE REGION AND WILL CONTINUE VCTS AT ALL TERMINALS
THROUGH EARLY EVENING. COVERAGE WILL DIMINISH WILL LOSS OF
HEATING THIS EVENING. 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.
SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER GUSTS
THIS AFTERNOON AT MEM AND KJBR.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1257 PM CDT SAT MAY 16 2015
.UPDATE...
18Z TAF DISCUSSION.
&&
.AVIATION...
NUMEROUS -SHRA CONTINUE NEAR ALL AIRPORTS THIS AFTERNOON ALTHOUGH
ACTIVITY IS BECOMING MORE SCATTERED WITH TIME. WILL HAVE -SHRA
UNTIL 21-00Z AT TERMINALS WITH VCSH AFTERWARDS...BUT ADDITIONAL
-SHRA AT CSV AFTER 03Z AS HRRR SHOWS ANOTHER ROUND MOVING THROUGH.
WILL LEAVE OUT MENTION OF TS DUE TO LIMITED INSTABILITY IN THE
VERY MOIST AIRMASS. IFR/MVFR CIGS/VIS WILL PREVAIL THROUGH 00Z
WITH MVFR/VFR AFTER THAT TIME. LIGHT SOUTH WINDS ANTICIPATED
THROUGH THE TAF PERIOD.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 927 AM CDT SAT MAY 16 2015/
UPDATE...MADE SOME MINOR ADJUSTMENTS TO POPS AND HOURLY
TRENDS...OTHERWISE FORECAST ON TRACK. SHOWERS COVERED MUCH OF MID
TN THIS MORNING...AND THIS WILL CONTINUE THROUGH MIDDAY. DURING
THE AFTERNOON...THE COVERAGE OF SHOWERS WILL DECREASE SLIGHTLY FROM
SOUTHWEST TO NORTHEAST...ALLOWING FOR SOME BREAKS IN THE RAINFALL.
THIS WILL ALSO ALLOW A LITTLE MORE DESTABILIZATION...AND A BETTER
CHANCE FOR ISOLATED THUNDERSTORMS. NO SEVERE WX IS EXPECTED.
RAINFALL AMOUNTS TODAY WILL RANGE MOSTLY FROM ONE QUARTER TO THREE
QUARTERS OF AN INCH. THE EXTENSIVE SHOWERS/CLOUDS WILL LIMIT HIGH
TEMPS TO THE 70S FOR MOST AREAS.
13
PREV DISCUSSION... /ISSUED 627 AM CDT SAT MAY 16 2015/
UPDATE...FOR 12Z AVIATION.
AVIATION...12Z TAF DISCUSSION.
SHOWERS ARE MOVING NORTHWARD INTO MIDDLE TN AT ISSUANCE AND SHOULD
BEGIN AFFECTING ALL 3 TERMINALS OVER THE NEXT COUPLE OF HOURS.
FLIGHT CATEGORIES WILL WAVER BETWEEN VFR AND MVFR FOR THE MOST
PART AS THESE LIGHT TO MODERATE RAIN MOVE THROUGH THE STATE. SOME
TS MAY BE MIXED IN BUT JUST COVERED WITH VCTS ATTM. ACTIVITY WILL
CONTINUE ON AND OFF THROUGHOUT THE DAY AND INTO THE EVENING HOURS.
SOME IFR CIGS/VIS CAN BE EXPECTED WITH ANY HEAVIER RAINS AND/OR TS.
SOUTHERLY WINDS WILL BE 8-12 KTS THROUGHOUT THE DAY WITH A GUST TO
20 OR 25 KTS POSSIBLE IN AND AROUND ANY TS THAT MAY AFFECT A
TERMINAL.
UNGER
PREV DISCUSSION... /ISSUED 218 AM CDT SAT MAY 16 2015/
DISCUSSION...SURFACE MAP AT 06Z SHOWS AN INCREASING SOUTHERLY
FLOW AS THE NEXT ACTIVE WEATHER SYSTEM DEEPENS OUT WEST. EARLIER
SHOWERS HAVE ALL BUT DISSIPATED ACROSS MIDDLE TENNESSEE, WITH
MINIMAL ACTIVITY EXPECTED OVERNIGHT. LOOK FOR MORE WIDESPREAD
SHOWERS TODAY AS A WEAK UPPER TROUGH PROVIDES SOME FOCUSING FOR
DEEPER MOISTURE, ALTHOUGH THE FORECAST MODEL SOUNDINGS SHOW ONLY
WEAK INSTABILITY TODAY. THUS, THUNDERSTORMS WON`T BE WIDESPREAD;
MOST OF TODAY`S ACTIVITY WILL BE SHOWERS ONLY.
TOMORROW, WE CAN EXPECT A GREAT DEAL MORE INSTABILITY, BUT LESS
MOISTURE CONTENT, SO POP`S ON SUNDAY WILL BE LOWER BUT THE CHANCE
OF STORMS WILL BE GREATER. AT THIS TIME, WE ARE EXPECTING GENERAL
THUNDERSTORMS ONLY, ALTHOUGH THE NEW DAY 2 CONVECTIVE OUTLOOK FROM
THE SPC DOES BRING A MARGINAL RISK RIGHT UP TO OUR DOORSTEP, SO A
FEW STORMS SUNDAY MAY AT LEAST BE STRONG. FROPA WILL LIKELY OCCUR
MONDAY EVENING. AFTER A BRIEF SPELL OF HIGH PRESSURE, A FOLLOW-UP
SYSTEM WILL MOVE THROUGH THURSDAY, BUT WITH MINIMAL EFFECTS.
TEMPERATURES NEXT WEEK WILL BE SLIGHTLY COOLER THAN THIS WEEK`S,
BUT NO SIGNIFICANT FLUCTUATIONS ARE EXPECTED THROUGH DAY 7.
ROSE
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION
NWS PORTLAND
220 PM PDT SAT MAY 16 2015
.SYNOPSIS...A LARGE BUT WEAK UPPER LEVEL LOW PRES SYSTEM WILL REMAIN
OVER THE REGION THROUGH MUCH OF THE COMING WEEK. A WEAK LOW LEVEL
OFFSHORE FLOW SUN AND MON WILL LEAD TO WARMER TEMPS AS WELL AS A
CHANCE FOR SHOWERS AND THUNDERSTORMS. ONSHORE FLOW WILL RETURN TUE
FOR A LITTLE COOLING AGAIN BUT A CONTINUED CHANCE OF SHOWERS.
THROUGH THE END OF THE WEEK TEMPERATURES WILL REMAIN CLOSE TO
SEASONAL NORMALS WITH ENOUGH INSTABILITY FOR A FEW SHOWERS.
&&
.SHORT TERM...RADAR AND SURFACE OBSERVATIONS HAVE SHOWN A FEW LIGHT
SHOWERS OVER THE NORTHERN PART OF THE FORECAST AREA EARLY THIS
AFTERNOON...THE RESULT OF SHALLOW INSTABILITY AND WEAK TROUGHINESS
ALOFT. A NEW UPPER LOW SEEN IN WATER VAPOR PICTURES WELL OFFSHORE
BETWEEN 135 AND 140W IS EXPECTED TO SLIDE SLOWLY SE INTO CA BY MON.
THIS TURNS THE MID AND UPPER LEVEL FLOW MORE TO THE SE WITH TIME...
WHILE WARMER TEMPS AT H8 WRAP IN FROM THE E. WITH REDUCED CLOUD
COVER AND WARMER H8 TEMPS WILL SEE TEMPS WARM BACK TO A LITTLE ABOVE
NORMAL FOR SUN AND MON. OVERALL THIS LEADS TO PROGRESSIVE
DESTABILIZATION OF THE ATMOSPHERE...WITH NAM AND GFS MODEL SOUNDINGS
INDICATING SOME INSTABILITY DEVELOPING OVER THE CASCADES BY SUN
AFTERNOON. BETTER INSTABILITY IS DEPICTED MON WITH AN EL AS HIGH AS
35K FT. THE POTENTIAL INSTABILITY ALSO EXTENDS AS FAR W AS THE COAST
RANGE MON. FORCING MECHANISM IS NOT QUITE AS OBVIOUS EITHER DAY AS
THE MON SHORTWAVE DEPICTED PREVIOUSLY BY GFS AND ECMWF IS MUCH
WEAKER. OVERALL WILL KEEP POPS CONSERVATIVE SUN MAINLY OVER THE
CASCADES...THEN INDICATE BETTER CHANCES FOR MON WITH LIKELY POPS
OVER THE CASCADES BASED ON GOOD INSTABILITY AND SOME DIFFLUNECE
ALOFT. WILL ALSO CARRY THE SLIGHT CHANCE FOR THUNDER AS FAR W AS THE
COAST RANGE BASED ON EASTERLY COMPONENT TO THE FLOW AND INSTABILITY.
AS THE CA LOW MOVES WELL E TOWARDS UTAH TUE...LOW LEVEL FLOW TURNS
BACK ONSHORE. THIS EXPECTED TO PUSH MARINE CLOUDS BACK INLAND FOR
COOLER TEMPS. MODEL SOUNDINGS HOWEVER CONTINUE TO INDICATE MARGINAL
INSTABILITY ALOFT WITH STILL SOME MID AND UPPER LEVEL MOISTURE. WILL
NEED TO KEEP A CHANCE FOR SHOWERS IN THROUGH TUE.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...BROAD UPPER-LEVEL LOW
REMAINS IN PLACE THROUGH THE WEEK...KEEPING COOLER CLOUDY MARINE
AIRMASS IN PLACE OVER THE REGION THROUGH FRIDAY. THIS WILL KEEP THE
AREA UNDER CLOUDY WEATHER WITH OCCASIONAL SHOWERS. MOISTURE STARTS
TO WANE LATER IN THE WEEK...WHICH WILL LIMIT SHOWERS TO THE
CASCADES. THE MODELS ARE SUGGESTING THAT AN UPPER LEVEL RIDGE TRIES
TO PUSH THE UPPER-LEVEL LOW OFF TO THE EAST FOR SATURDAY WHICH COULD
DRY WEATHER OUT FOR THE WEEKEND...BUT CONFIDENCE IS LOW ON TIMING
AND WHETHER THIS WILL ACTUALLY OCCUR THIS FAR OUT IN THE FORECAST
PERIOD. -MCCOY
&&
.AVIATION...IFR CIGS WITH PERIODS OF IFR VSBYS WITH LIGHT DRIZZLE
WILL CONTINUE AT THE COAST AT LEAST THROUGH 19Z AND PERHAPS INTO
THE AFTERNOON THROUGH 21Z BEFORE IMPROVING TO MVFR. EXPECT A
RETURN TO IFR CIGS LATE OVERNIGHT AROUND 10Z. INLAND...MODEL TIME
HEIGHT MOISTURE SUPPORTS MARINE STRATUS CONTINUING OVERNIGHT WITH
A FAVORING OF THE MORE PESSIMISTIC GFS. NAM12 APPEARS TO CLEAR
THE SKIES TOO FAST AND ESPECIALLY GIVEN THE LONG FETCH OF UPSTREAM
MOISTURE WHICH SHOULD CONTINUE TO REINFORCE THE MARINE LAYER. AS
SUCH...EXPECT THE LARGELY VFR CIGS NOW TO LOWER THIS EVENING BACK
TOWARD THE 025 AGL MARK WHERE THEY WILL PERSIST THROUGH 12Z AT
LEAST AND LIKELY THROUGH 18Z BEFORE SHOWING SIGNS OF BREAKING UP.
KPDX AND APPROACHES...VFR STRATUS CIGS AROUND 030-040 WILL LIKELY
STAY IN PLACE THROUGH AT LEAST 12Z. CONFIDENCE HAS IMPROVED WITH A
PERSISTENT VFR STRATUS TO STAY IN PLACE BUT LIKELY LOWER CLOSER
TO THE 025 MARK AROUND 06Z. FIRST IMPRESSION HAS THE 025 STRATUS
DECK REMAINING IN PLACE THROUGH THE MORNING PUSH WITH HINTS OF
CLEARING AFTER 16Z AT THE EARLIEST. /JBONK
&&
.MARINE...WEAK SURFACE HIGH PRESSURE OFFSHORE WILL COMBINE WITH
SURFACE LOW PRESSURE INLAND TO PRODUCE MAINLY NORTHWEST TO NORTH
WINDS FOR THE WEEK AHEAD. WIND GUSTS STAY BELOW 20 KTS FOR THE
ENTIRE FORECAST.
RELATIVELY MILD SWELL CONDITIONS FOR THE WEEK AHEAD. A COUPLE
SMALLER SWELL TRAINS COMBINE FOR HEIGHTS OF 4 TO 5 FEET. LONGER
PERIOD SWELLS AROUND 15 TO 17 SECONDS WILL SHORTEN INTO THE 11 TO
14 SECOND RANGE BY MID WEEK.
EXPECT CHOP DURING THE EBBS BUT WITH A HEIGHT OF 5 FEET AND MAYBE
7 FEET ON THE VERY STRONG OVERNIGHT EBB...WILL NOT MEET CRITERIA
AS WIND SPEEDS DO NOT SUPPORT CREATING MAIN CHANNEL BREAKERS.
/JBONK
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
Area Forecast Discussion
National Weather Service Spokane WA
1247 PM PDT SAT MAY 16 2015
.SYNOPSIS...
Scattered showers with embedded thunderstorms will be possible
for the next several days. The best chance of widespread showers
and isolated thunderstorms will be late this afternoon and
Sunday, especially over north Idaho and Northeast Washington.
Seasonably mild conditions will continue through the next week
with showers possible over the higher terrain.
&&
.DISCUSSION...
A minor update has been sent to extend the band of wrap around
rain slightly to the west to include the Lewiston area. Radar
trends as well as the HRRR suggest this area of rain will shift
south and east of the Lewiston area and Camas Prairie by late
morning so this is not expected to last much longer. For this
afternoon the HRRR shows increasing shower and isolated
thunderstorm development over NE Washington Mountains and Idaho
Panhandle, and then drifting southwestward into the Spokane area,
Okanogan Highlands, and Palouse by late this afternoon or early
evening as a low level boundary helps initiate convection.
Elevated dew points currently in the mid 40s to lower 50s around
Spokane, Deer Park, and Sandpoint along with an eroding mid level
cloud deck should allow for some morning and afternoon sun which
will allow for increased surface heating to help inititate
convection. It is this area that the 06z GFS has the best
instability with uncapped CAPE values as high as 500-1000 J/KG. Brief
heavy rain...small hail...and wind gusts to around 30 mph are the
main threats with these storms. JW
&&
.AVIATION...
18z TAFS: Main concern will the development of showers and
isolated thunderstorms over NE Washington and North Idaho through
early this evening. KGEG/KSFF/KCOE are most favored for this
activity...although with only isolated coverage expected only went
with VCTS in the TAF between 23z-02z based on HRRR timing which is
currently lining up well with radar data. This activity should
decrease after sunset although showers may increase in North
Central WA overnight where the best mid level instability will
lie ahead of a closed low near Vancouver Island. Mainly VFR
conditions are expected through 18z Sun...although in heavier
showers or storms a lowering of visibility is likely. Also
overnight an increase in NE winds for KGEG/KSFF/KCOE should limit
the fog/stratus potential. The NAM shows the best stratus
potential overnight at KPUW...although confidence is low-moderate
of this occurring as the GFS shows drying in the boundary layer
late tonight/early Sunday as easterly flow begins to increase. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 72 51 69 49 72 49 / 40 60 10 10 10 10
Coeur d`Alene 68 48 69 45 72 47 / 70 60 10 10 10 10
Pullman 65 49 67 44 71 45 / 40 60 30 20 20 20
Lewiston 70 54 73 51 76 53 / 40 60 30 30 30 20
Colville 77 52 72 48 74 50 / 40 60 20 10 10 10
Sandpoint 69 48 69 40 70 41 / 70 50 10 10 10 10
Kellogg 65 46 68 43 70 44 / 70 60 10 10 10 10
Moses Lake 78 53 73 50 77 51 / 10 30 40 20 10 10
Wenatchee 78 55 72 54 78 55 / 10 50 50 20 10 10
Omak 79 52 72 50 76 49 / 10 50 50 20 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
337 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/...COMING SOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...DENSE FOG ADVISORY UNTIL 10 AM CDT SUNDAY FOR LMZ643>646.
&&
$$
TONIGHT/SUNDAY AND AVIATION/MARINE...MRC
SUNDAY NIGHT THROUGH SATURDAY...GEHRING