Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/01/16
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
855 PM MST SAT APR 30 2016
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION FROM THE NORTH
TONIGHT INTO SUNDAY. THIS WILL RESULT IN A CHANCE OF AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS...PARTICULARLY OVER THE MOUNTAINS
OF EASTERN ARIZONA SUNDAY. CLEARING IS EXPECTED SUNDAY NIGHT...WITH
DRY AND MUCH WARMER WEATHER DEVELOPING NEXT WEEK. HOT WEATHER IS
EXPECTED NEXT WEEK WITH DESERT TEMPERATURES WARMING INTO THE MID TO
UPPER 90S. THERE ARE HINTS OF ANOTHER PACIFIC WEATHER SYSTEM MOVING
INTO THE REGION BY LATE NEXT WEEK OR NEXT WEEKEND.
&&
.DISCUSSION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE PREVALENT THIS
AFTERNOON ACROSS PORTIONS OF THE AZ LOWER DESERTS...INCLUDING THE
PHOENIX AREA. THE STORMS DEVELOPED IN AN AREA CHARACTERIZED BY VERY
STRONG ASCENT AHEAD OF TIGHT VORT MAX ACROSS THE WESTERN AZ DESERTS.
LATEST WV IMAGERY AND STREAMLINE ANALYSIS SHOWS THE VORT SHEARING OUT
AS IT TRANSLATES EASTWARD ACROSS CENTRAL AZ. THE LOSS OF LARGER
SCALE ASCENT AND DIABATIC HEATING HAS CONSEQUENTLY RESULTED IN A
RAPID DECREASE IN INSTABILITY AND COVERAGE OF SHOWERS AND STORMS THIS
EVENING. LATEST HI-RES GUIDANCE INCLUDING THE HRRR CONTINUE TO SHOW
THE EXISTING ACTIVITY...MAINLY CONCENTRATED EAST OF THE PHOENIX AREA
DISSIPATING OVERNIGHT. CURRENT FORECAST HANDLES THIS WELL...THOUGH
SOME ADJUSTMENTS WERE MADE TO THE SHORT-TERM TEMPERATURES TO ACCOUNT
FOR THE RAIN-COOLED AIR EARLY THIS EVENING.
&&
.PREVIOUS DISCUSSION...
AT 2 PM A VIGOROUS UPPER LEVEL LOW PRESSURE SYSTEM WAS MOVING INTO
ARIZONA...WITH THE LOW CENTER PUSHING EASTWARD AND INTO WEST CENTRAL
AZ. BEST AREA OF PVA/DIFLUENCE AND Q-CONVERGENCE WAS FOCUSED ACROSS
WEST-CENTRAL AND SOUTH-CENTRAL ARIZONA EARLY THIS AFTERNOON AND
LATEST SPC MESOANALYSIS GRAPHIC INDICATED THAT BEST INSTABILITY WAS
ALSO IN THAT AREA WITH OVER 500 J/KG OF MLCAPE PRESENT AT 1 PM. WITH
PWAT VALUES APPROACHING THREE QUARTERS OF AN INCH OUT WEST WE HAVE A
GOOD COMBINATION OF MOISTURE...INSTABILITY AND LIFT AND NOT
SURPRISINGLY...SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
AHEAD OF THE LOW...ACROSS EASTERN LA PAZ AND YUMA COUNTIES AND
WESTERN MARICOPA COUNTY. SOME OF THE STRONGEST CELLS ARE IN THE
PRIME DIFLUENT AREA AHEAD OF THE LOW CENTER OVER NERN LA PAZ COUNTY.
SO FAR STORMS HAVE BEEN SUB SEVERE AND WE HAVE COVERED THEM WITH
SIGNIFICANT WEATHER ADVISORIES AND SOCIAL MEDIA POSTS. FOR THE REST
OF THE AFTERNOON AND INTO THE EVENING THERE WILL CONTINUE TO BE A
CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS SOUTH CENTRAL
ARIZONA...WITH SLIGHT CHANCES FURTHER WEST IN THE AREAS BEHIND THE
PASSING UPPER LOW. HIGH TEMPERATURES TODAY WILL BE ON THE COOL SIDE
AS THE UPPER LOW AND ASSOCIATED CLOUD COVER MOVES ACROSS THE
AREA...WITH MOST READINGS IN THE UPPER 70S TO LOW 80S OVER THE LOWER
DESERTS. SCATTERED SHOWERS/STORMS WILL CONTINUE TO INCREASE ACROSS
THE GREATER PHOENIX AREA DURING THE MID TO LATE AFTERNOON...THEN
CONTINUE INTO THE EVENING HOURS BEFORE STARTING TO DISSIPATE.
LATER TONIGHT INTO SUNDAY...AS THE EVENING WEARS ON AND WE MOVE INTO
SUNDAY...THE MAIN UPPER LOW CONTINUES TO SHIFT OFF TO THE
EAST/NORTHEAST AND THE DYNAMICAL FORCING BECOMES MINIMAL WITH TIME.
MID LEVEL Q CONVERGENCE BULLSEYE MOVES INTO NEW MEXICO OVERNIGHT
WITH A MORE SUBSIDENT AREA OF Q DIVERGENCE MOVING INTO THE LOWER
CENTRAL DESERTS. NVA/DVV OVERSPREAD THE AREA FROM THE WEST...AND THE
MAIN UPPER JET AXIS MOVES WELL OFF TO THE EAST AND OFFERS NO SUPPORT
FOR UVV. PRETTY MUCH...BY LATE NIGHT TONIGHT AND SUNDAY WE ARE LEFT
WITH THERMODYNAMIC SUPPORT FOR SHOWERS/CONVECTION AS COOL AIR ALOFT
REMAINS IN PLACE OVER AN AREA OF ELEVATED LOW LEVEL MOISTURE.
FORECAST CAPE VALUES HOWEVER ARE LOW COMPARED TO THIS
AFTERNOON...MOSTLY LESS THAN 200 J/KG AND THE BEST CAPE STAYS ACROSS
HIGH TERRAIN AREAS NORTH AND EAST OF PHOENIX. WE WILL CONTINUE TO
KEEP A CHANCE OF SHOWERS OR STORMS GOING OVER SRN GILA COUNTY
THROUGH THE DAY ON SUNDAY BUT LOWER POPS TO THE 15-20 PERCENT
BALLPARK OVER THE LOWER CENTRAL DESERTS WITH TIME...WITH POPS OVER
THE FAR WESTERN DESERTS AND SERN CA LOWERING INTO THE SINGLE DIGITS.
WE SHOULD SEE SOME COOLING ON SUNDAY...GIVEN THE NATURE OF THE COLD
POOL ALOFT MOVING ACROSS THE AREA AND THE CLOUD COVER...MOST
SIGNIFICANT OVER SOUTH CENTRAL AZ...AND WE WILL LOWER OUR HIGHS A
COUPLE DEGREES WITH PHOENIX DROPPING TO A HIGH OF JUST 80 ON SUNDAY.
ACTUALLY...WOULD NOT BE SURPRISED IF THE HIGH IN PHOENIX SUNDAY
REMAINS IN THE 70S.
ALTHOUGH THE MAIN LOW WILL CONTINUE TO PUSH OFF TO THE EAST SUNDAY
NIGHT...ONE MORE WEAK BAGGY TROF OVER SRN CA/SRN NV WILL SLIDE EAST
AND INTO NORTHERN ARIZONA KEEPING A SLIGHT CHANCE OF EVENING SHOWERS
IN PLAY OVER THE HIGHER TERRAIN OF JOSHUA TREE NP AS WELL AS AREAS
NORTH AND EAST OF PHOENIX. OTHERWISE EXPECT POPS IN THE SINGLE
DIGITS OVER THE LOWER AZ AND CA DESERTS.
MONDAY THROUGH THURSDAY...
DRY WESTERLY FLOW WILL DEVELOP MONDAY...FOLLOWED BY A BUILDING HIGH
PRESSURE SYSTEM TUE...WED...AND MOST OF THURSDAY. THIS WILL RESULT
IN MOSTLY CLEAR SKIES AND MUCH WARMER TEMPERATURES.
THURSDAY NIGHT THROUGH SATURDAY...
MODELS HAVE BEEN FORECASTING ANOTHER PACIFIC WEATHER SYSTEM TO
APPROACH SOUTHERN CA LATE THURSDAY AND FRIDAY. ENSEMBLE SPREAD
CONTINUES BO BE WIDE WITH RESPECT TO TIMING AND INTENSITY. HOWEVER
ITS A NEAR CERTAINTY THAT ANOTHER PACIFIC SYSTEM WILL MOVE INTO THE
REGION BY THE END OF NEXT WEEK AND WEEKEND FOR MORE COOLING...
WIND...AND A THREAT OF SHOWERS. FOR NOW WE FEEL COMFORTABLE
INTRODUCING JUST A SLIGHT CHANCE OF SHOWERS AREA-WIDE FRIDAY AND
SATURDAY WITH NO SPECIFICS NOR RESOLUTION.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WITH A LOW PRESSURE STORM SYSTEM SWEEPING THROUGH THE REGION ON
SATURDAY AFTERNOON AND EVENING EXPECT SOME SCATTERED RAIN SHOWERS
AND THUNDERSTORMS AND VERY BREEZY SOUTH TO SOUTHWEST WINDS WITH
PERIODIC GUSTS OF 20 TO 25KTS. THROUGH ABOUT 03Z. EXPECT THE LOWEST
CIGS TO VARY FROM 7K TO 11K FT. EXPECT WEST TO SOUTHWEST WINDS TO
TAPER OFF TO 7 TO 10KTS. TONIGHT WITH BROKEN CIGS AT ABOUT 9K FT.
LIGHT EASTERLY COMPONENT WINDS WILL BE FAVORED BEGINNING LATE
SATURDAY NIGHT AND EARLY SUNDAY MORNING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
VERY BREEZY TO WINDY NORTHERLY COMPONENT WINDS WITH SOME GUSTS TO
20KTS. ARE EXPECTED FOR KBLH ALONG WITH RAIN SHOWERS AND
THUNDERSTORMS IN THE VICINITY THROUGH EARLY EVENING. BROKEN TO
OVERCAST CIGS FROM 7 TO 11K FT. ARE ALSO LIKELY THROUGH THIS
EVENING. WINDY WEST AND NORTHWESTERLY WINDS WITH GUSTS OF 25 TO
30KTS ARE EXPECTED FOR KIPL WITH CLEAR TO PARTLY CLOUDY SKIES.
LIGHTER WESTERLY TO NORTHWESTERLY WINDS ARE EXPECTED FOR BOTH SITES
BY 03 TO 04Z.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
WITH A DRIER AND WARMER AIRMASS IN PLACE EXPECT ABOVE NORMAL
TEMPERATURES THROUGH THURSDAY WITH THE HOTTEST DAY ON WEDNESDAY
REACHING INTO THE MID TO UPPER 90S IN THE LOWER DESERTS. EXPECT
ELEVATED FIRE DANGER ON WEDNESDAY AND THURSDAY WITH MINIMUM
HUMIDITIES FALLING TO THE 6 TO 11 PERCENT RANGE AND BREEZY SOUTHERLY
TO SOUTHWESTERLY WINDS SPREADING THROUGH THE LOWER DESERTS.
CONDITIONS WILL IMPROVE ON FRIDAY AND SATURDAY WHEN THE NEXT STORM
SYSTEM WILL COOL HIGH TEMPERATURES TO THE LOW TO MID 80S WITH
MINIMUM HUMIDITIES IN THE MID TEEN TO MID 20 PERCENT RANGE BY
SATURDAY.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...CB/VASQUEZ
AVIATION...SAWTELLE
FIRE WEATHER...SAWTELLE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
920 AM MST FRI APR 29 2016
.SYNOPSIS...
EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAINLY NORTH
OF TUCSON THROUGH MONDAY. STRENGTHENING HIGH PRESSURE ALOFT WILL
THEN PROVIDE DRY CONDITIONS WITH A STRONG WARMING TREND BY THE
MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...VISIBLE SATELLITE IMAGERY DEPICTED SCATTERED TO BROKEN
CLOUDS NORTH TO NORTHEAST OF TUCSON. OTHERWISE...CLEAR SKIES
PREVAILED ACROSS SE ARIZONA. SURFACE WINDS WERE GENERALLY CALM
EXCEPT ACROSS THE UPPER GILA RIVER VALLEY WHERE WIND GUSTS TO NEAR
25 MPH WERE ONGOING. DEWPOINTS AT LOWER ELEVATIONS VALID 16Z RANGED
FROM THE MID 20S-MID 30S...AND THESE TEMPS WERE ABOUT 5-15 DEGS
HIGHER VERSUS 24 HOURS AGO.
MEANWHILE...SURFACE TEMPS VALID 16Z WERE ABOUT 5-15 DEGS COOLER
VERSUS THIS TIME THURSDAY. 29/12Z KTWC SOUNDING TOTAL PRECIP WATER
VALUE OF 0.43 INCH WAS 0.16 INCH HIGHER VERSUS 24 HOURS AGO. 29/12Z
UPPER AIR PLOTS DEPICTED A BROAD TROUGH OVER THE WRN CONUS...WITH
LOW PRESSURE CENTERED NEAR THE FOUR CORNERS...AND ANOTHER LOW
CENTERED OVER WRN MONTANA. MODERATE TO STRONG GENERALLY WLY FLOW
ALOFT PREVAILED ACROSS SE ARIZONA.
WATER VAPOR IMAGERY DEPICTED A CYCLONIC CIRCULATION SYSTEM MOVING
SEWD ACROSS WRN PIMA COUNTY AT THIS TIME. THIS SYSTEM WAS
INITIALIZED AS A VORT MAX VIA THE 29/12Z NAM/GFS...AND WILL SEWD
INTO NRN CHIHUAHUA BY THIS EVENING. THESE SOLUTIONS AS WELL AS
SATELLITE TRENDS SUGGEST THAT CLEAR SKIES OR JUST FEW CUMULOFORM
CLOUDS WILL PREVAIL FROM TUCSON SWD/WWD THRU THIS AFTERNOON.
MEANWHILE...SEVERAL HRRR SOLUTIONS FAVOR THE CONTINUATION OF CHANCE-
CATEGORY POPS MAINLY ACROSS THE WHITE MOUNTAINS INTO THIS EVENING.
THERE APPEARS TO BE ENOUGH PROGGED INSTABILITY TO SUPPORT A CHANCE
OF THUNDERSTORMS AS WELL. WLY/NWLY WINDS THIS AFTERNOON WILL BE LESS
VERSUS THUR AFTERNOON...THOUGH SOMEWHAT GUSTY ACROSS THE UPPER GILA
RIVER VALLEY. HIGH TEMPS THIS AFTERNOON WILL BE ABOUT 3-8 DEGS
COOLER VERSUS THUR.
&&
.AVIATION...VALID THRU 30/18Z.
NORTH TO NORTHEAST OF KTUS EXPECT ISOLATED TO SCATTERED -SHRA WITH
-TSRA THIS AFTERNOON. CLOUD DECKS WILL GENERALLY BE AROUND 8-12K FT
AGL INTO SATURDAY MORNING. KTUS VICINITY SOUTHWARD...CLEAR SKIES
THROUGH MUCH OF THE PERIOD WITH SCATTERED CLOUDS AROUND 10-15K FT
AGL MAINLY THIS AFTERNOON. SURFACE WIND THIS AFTERNOON AND EVENING
WILL BE WLY/NWLY AT 10-18 KTS WITH GUSTS TO NEAR 25 KTS. SURFACE
WIND DIMINISHING TO LESS THAN 10 KTS MOST LOCALES LATE TONIGHT...
THEN SURFACE WIND SATURDAY MORNING SELY TO SWLY AT 10-15 KTS WITH
GUSTS TO 20 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS
MAINLY NORTH OF TUCSON THROUGH MONDAY. OTHERWISE...DRY CONDITIONS
WILL PREVAIL INTO THE MIDDLE OF NEXT WEEK. EXPECT AFTERNOON
BREEZINESS FROM THE NORTHWEST TO SOUTHWEST TO CONTINUE THROUGH THIS
WEEKEND FOLLOWED BY LESS WIND INTO THE MIDDLE OF NEXT WEEK.
&&
.PREV DISCUSSION /254 AM MST/...EARLY MORNING WATER VAPOR IMAGERY
CONTINUES TO REVEAL SLOW MOVING LOW PRESSURE OVER THE FOUR CORNERS.
THIS IS THE SYSTEM THAT BROUGHT STRONG WINDS TO PARTS OF THE AREA
YESTERDAY ALONG WITH A FEW LATE-AFTERNOON/EVENING SHOWERS NORTH/EAST
OF TUCSON. SINCE THEN IT HAS MOVED EAST AND TRIGGERED EARLY MORNING
CONVECTION ACROSS THE TEXAS PANHANDLE. IN ITS WAKE...NORTHWESTERLY
FLOW PERSISTS ACROSS THE AREA BUT A WEAK SHORTWAVE TROUGH IS NOTED
IN THE FLOW NEAR LAS VEGAS. CLOUDS ARE ON THE INCREASE ACROSS
CENTRAL ARIZONA BUT MUCH OF SOUTHEASTERN ARIZONA REMAINS CLEAR AS OF
09Z. TEMPS REMAIN SOMEWHAT MILD THIS MORNING...GENERALLY IN THE
MID/UPPER 50S GIVEN 5-10KTS OF WIND AT NEARLY ALL SITES.
THE AFOREMENTIONED SHORTWAVE TROUGH WILL SWEEP THROUGH THE AREA
TODAY BUT WILL REMAIN TO THE NORTH OF TUCSON. MODEST INCREASES IN
MOISTURE IMMEDIATELY AHEAD OF THE TROUGH COULD BE JUST ENOUGH TO
PRODUCE SOME LIGHT SHOWERS/SPRINKLES BUT THIS WOULD LIKELY BE
CONFINED TO THE HIGHER TERRAIN LOCATIONS NORTH/EAST OF TUCSON.
FORECAST SOUNDINGS ARE LARGELY UNIMPRESSIVE ACROSS THE LOWER
ELEVATIONS AND POPS WILL REMAIN BELOW 10 PERCENT. SHORTWAVE RIDGING
IS FORECAST ACROSS THE AREA LATE FRIDAY NIGHT INTO SATURDAY...THUS
THE WINDOW OF OPPORTUNITY FOR PRECIP IS NARROW.
ANOTHER...DEEPER LOW IS FORECAST TO DROP THROUGH ARIZONA ON SUNDAY
AND AT FIRST GLANCE IT MIGHT SEEM THAT PRECIP CHANCES WOULD BE
SIGNIFICANT...ESPECIALLY GIVEN H5 HEIGHT PERCENTILES SOMEWHERE ON
THE LOWER END OF THE SPECTRUM /BETWEEN 2-5 PERCENT/. HOWEVER...
MOISTURE /PWATS AND IVT/ IS FORECAST TO REMAIN WELL WITHIN
CLIMATOLOGICAL NORMALS FOR EARLY MAY. FORECAST SOUNDINGS ARE ONCE
AGAIN LARGELY NOT SUPPORTIVE OF PRECIPITATION ACROSS THE LOWER
ELEVATIONS AND ASIDE FROM A CHANCE OF SHOWERS IN THE WHITES...THE
MAIN IMPACT WILL BE IN THE FORM OF WINDS AND COOLER TEMPS. GEFS
PLUMES ARE DRY ACROSS THE LOWER ELEVATIONS AND NAEFS INDICATES 20-30
POPS WOULD BE WARRANTED ONLY TO THE NORTH.
LOOKING TOWARD NEXT WEEK...HIGH AMPLITUDE RIDGING WILL TAKE SHAPE
FROM TUESDAY THROUGH AT LEAST THURSDAY...RESULTING IN A RETURN OF
THE ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS. THERE IS SOME
SUGGESTION FROM BOTH THE DETERMINISTIC AND PROBABILISTIC ECMWF AND
GFS THAT A LOW WILL DROP THROUGH SOUTHERN CALIFORNIA...POSSIBLY
DRAWING MOISTURE NORTHWARD INTO NEW MEXICO AND EASTERN ARIZONA. THE
AMPLITUDE OF THE TROUGH AND MAGNITUDE OF ANY MOISTURE ADVECTION IS
STILL UNCERTAIN AT THIS TIME BUT I FELT THAT HIGHER THAN CLIMO POPS
ARE WARRANTED IN THIS CASE ALONG WITH COOLER TEMPERATURES.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1123 AM MDT FRI APR 29 2016
.UPDATE...
ISSUED AT 1120 AM MDT FRI APR 29 2016
MODIFICATIONS HAVE BEEN MADE TO SNOW AMOUNTS FOR TODAY AND
TONIGHT. BASICALLY...LOWERED AMOUNTS IN THE MTNS...ESPLY WEST OF
THE CONTINENTAL DIVIDE AND FOR THE FOOTHILLS...ESPLY NORTH OF
HIGHWAY 7. RAISED SNOW ACCUMS IN PARK COUNTY BASED ON RECENT
SPOTTER REPORT...AND ALSO RAISED SNOW AMTS ACRS THE SERN CORNER OF
THE CWA...IE ELBERT AND LINCOLN COUNTIES WHERE WX SPOTTERS AND
WX CAMS INDICATE 3-6 INCHES OF SNOW ON THE GROUND...CENTERED
AROUND LIMON AND HUGO. LASTLY...LOWERED SNOW AMOUNTS OVR NERN
PORTIONS OF THE I-25 CORRIDOR WHERE LITTLE TO NO SNOW HAS YET TO
PILE UP AND PCPN UP TO NOW HAS MAINLY BEEN RAIN OR DRIZZLE.
OVER THE NEXT SEVERAL HOURS...STILL ANTICIPATE A RAMP UP ON PRECIP
ACROSS NENR COLORADO WITH MEAN LAYER FLOW TURNING MORE EASTERLY AS
THE 500-400MB LOW CONTINUES TO TRACK EAST ALONG THE COLORADO/NEW
MEXICO BORDER. PINPOINTING SNOW AMOUNTS CONTINUE TO BE BIGGEST
CHALLENGE AS MODELS CONTINUE TO OFFER CONSIDERABLY DIFFER QPF
VALUES...ESPLY ON THE PLAINS. THE GFS BY FAR IS THE WETTEST OF
THE MODELS...AND IT HAS BEEN FOR THE PAST FEW DAYS. THE EC...SREF
AND HRRR QPF NUMBERS SEEM MORE REASONABLE BASED ON THE QG ASCENT...
INSTABILITY AND OROGRAPHIC LIFT PREDICTED BY THE MODEL BLEND.
THEREFORE WILL USE QPF ROUGHLY HALF OF THAT OFFERED BY THE GFS TO
REVISE SNOW AMOUNTS. LIQUID/SNOW RATIOS ON THE PLAINS BASED ON
FCST TEMPS IN THE 7.2 TO 9.4 TO 1 RANGE. HIGHER ELEVATIONS WHERE
TEMPS COLDER BY 4-8 DEGS...H2O TO SNOW RATIOS IN THE 12 TO 17 TO 1
RANGE.
NO CHANGES TO CURRENT WINTER WEATHER HIGHLIGHTS AT THIS TIME. IF
WE SEE MORE SNOW ACCUMULATION ON ROADWAYS ACRS ELBERT...LINCOLN
AND WASHINGTON COUNTIES...A WINTER WEATHER ADVISORY MAY BE
NECESSARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 306 AM MDT FRI APR 29 2016
WATER VAPOR IMAGERY SHOWING ELONGATED UPPER LOW FROM EASTERN UTAH
TO NORTHWEST NEW MEXICO. PRECIPITATION HAS BEEN SLOW TO DEVELOP
ESPECIALLY NORTHERN SECTIONS OF THE CWA. THERE HAS BEEN A GENERAL
NORTHWARD SPREAD OF THE PRECIP WITH MAINLY SNOW FROM DENVER
SOUTHWARD. FURTHER NORTH TEMPERATURES ARE A BIT HIGHER SO LIGHT
RAIN AND DRIZZLE CONTINUE TO FALL FROM BOULDER NORTHWARD. EVEN
WITH THE HEAVIER PRECIP SHOWN ON RADAR...OBSERVATIONS SITES AT
DENVER ARE ONLY SHOWING LIGHT SNOW. PART OF THE PROBLEM IS THE
LIGHT SOUTHEAST FLOW WHICH IS DOWNSLOPING OVER THE FRONT RANGE SO
ONLY A VERY WEAK UPSLOPE COMPONENT. WE ALSO HAVE E A STRONG
SOUTHERLY MID LEVEL FLOW WHICH ALSO MAY BE LIMITING PRECIP. EVEN
NOW THERE APPEARS TO BE DRYING OR DIMINISHMENT OF PRECIP OVER THE
PALMER DIVIDE. LATEST HRRR PICKS UP ON THIS SO A LULL IN THE
PRECIP EARLY THIS AM BEFORE BECOMING WIDESPREAD AGAIN BY LATER BY
LATER THIS MORNING.
AS FOR THE WINTER HILITES...AM CONCERNED THAT WILL NOT BE ABLE TO
MAKE SNOWFALL CRITERIA IN THE MOUNTAINS AND FOOTHILLS. HAVE
LOWERED AMOUNTS....AND TOTAL VALUES LOOK NOW TO BE AROUND 4 TO 9
INCHES ALONG EAST5 SLOPES AND 4 TO 6 INCHES OVER THE PALMER
DIVIDE. THERE JUST DOES NOT SEEM TO BE ENOUGH STRONG UPSLOPE FLOW
DUE TO THE ELONGATED UPPER LOW AND NOT A NICE COMPACT SYSTEM. FOR
NOW WILL LEAVE THE HILITES AS THE BEST POTENTIAL IS STILL TO COME
FOR THIS AFTERNOON. DAY SHIFT MAY DECIDE TO CANCEL HILITES IF
THINGS DON`T COME TOGETHER. OVERALL...HEAVIEST QPF AMOUNTS WILL BE
OVER THE EASTERN PLAINS OF COLORADO WITH LESSER AMOUNTS FURTHER
WEST.
THE UPPER LOW IS PROGGED TO CONSOLIDATE A BIT BETTER BY LATER
THIS AFTERNOON OVER SOUTHEAST COLORADO WHICH LOOKS TO SHOW THE
BEST POTENTIAL FOR PRECIP UNDER THE STRONGEST QG ASCENT.
TEMPERATURES WILL HOVER IN THE LOWER TO MID 30S TODAY AND GIVEN
HIGH SUN ANGLES...MOST OF THE SNOW WILL MELT ON PAVEMENT SURFACES
BUT STILL SOME LIGHT ACCUMULATIONS ON GRASSY SURFACE. LOOK FOR
GRADUAL IMPROVEMENT LATER THIS EVENING AND OVERNIGHT AS THE UPPER
LOW MOVES INTO CENTRAL KANSAS BY LATER TONIGHT. THERE WILL STILL
BE A FAIR AMOUNT OF WRAP AROUND PRECIP OVER FAR NORTHEAST PLAINS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 306 AM MDT FRI APR 29 2016
ON SATURDAY...THE UPPER LOW WILL BE MOVING INTO SOUTHWESTERN
NEBRASKA WITH MOISTURE WRAPPING AROUND THE SYSTEM AND MOVING
ACROSS THE NORTHEAST PLAINS. HIGHEST POPS WILL BE NORTH AND EAST
OF DENVER...WITH THE BEST CHC OF ACCUMULATING SNOWFALL...ALBEIT
LIGHT...IN THE MORNING. AS THE SYSTEM CONTINUES TO TRACK TO THE
NORTHEAST SATURDAY AFTN/EVNG...THE MDLS SHOW WEAK DOWNWARD QG
OVER THE CWA. NAM12 SPATIAL CROSS SECTIONS MAINTAIN A WEAK ELY
FLOW BLO 700 MB SATURDAY NIGHT...BUT MUCH DRIER ALOFT. BEST CHC OF
PCPN WILL BE IN AND NEAR THE FRONT RANGE FOOTHILLS SATURDAY NIGHT
INTO SUNDAY MORNING. WITH THE DRIER AIR ALOFT...COULD SEE PATCHY
FREEZING DRIZZLE DEVELOP SO WILL THROW A LITTLE BIT OF THAT INTO
THE GRIDS. SUNDAY AFTERNOON INTO MONDAY MORNING...ANOTHER CLOSED
PACIFIC SYSTEM AROUND THE FOUR CORNERS REGION AT 18Z SUNDAY IS
PROGGED TO OPEN UP AND MOVE INTO NEBRASKA BY 18Z MONDAY. THIS
SYSTEM IS FAIRLY WEAK...BUT IT DOES HAVE SOME QG ASCENT IN THE MID
LEVELS AND DOES DEEPEN THE MOISTURE ALONG THE FRONT RANGE.
THEREFORE COULD SEE ANOTHER CHANCE OF PCPN...ESPECIALLY FROM THE
URBAN CORRIDOR WESTWARD. TEMPERATURES WILL MODIFY FURTHER ON
TUESDAY BUT AN INTERESTING FEATURE DOES SHOW UP ON THE ECMWF. A
LOW PRESSURE SYSTEM OVER SERN MT/WRN NORTH DAKOTA AROUND 18Z
MONDAY IS PROGGED SLIDE NORTHEAST TO SOUTHWEST AROUND AN OMEGA
RIDGE SITTING OVER THE NRN ROCKIES...AND INTO NWRN CO BY 18Z
TUESDAY. THIS COULD BRING A CHC OF PCPN TO THE REGION TUESDAY
AFTN/EVNG. THE GFS ON THE OTHER HAND SHOWS NO SUCH FEATURE...SO
MAINLY CHC POPS MAINLY OVER THE HIGHER TERRAIN AT THAT TIME. TREND
FOR DRIER AND WARMER STILL ON TRACK FOR THE REST OF THE WEEK WITH
AN UPPER LEVEL RIDGE THE PREVAILING FEATURE FOR WEDNESDAY AND
THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1120 AM MDT FRI APR 29 2016
ILS CIGS AND VSBYS ANTICIPATED AT DENVER AREA AIRPORTS THROUGH AT
LEAST 22Z THIS AFTERNOON. VSBY REDUCTIONS WILL BE A COMBINATION OF
SNOW AND FOG. WITH THE CORE OF THIS STORM SYSTEM PREDICTED TO
PASS TO OUR EAST AROUND MID-AFTERNOON TODAY...SHOULD SEE THE
MOIST UPSLOPE FLOW GRADUALLY WEAKENING AND BECOMING MORE
NORTHERLY IN DIRECTION. THIS SHOULD RESULT IN A REDUCTION IN
SNOWFALL RATES AND A SLIGHT IMPROVEMENT IN CIG HEIGHTS AND VSBYS
AT KBJC AND KDEN. NOT SO AT KAPA WHERE ILS CONDITIONS ARE LIKELY
TO PERSIST UNTIL AT LEAST 02Z-03Z THIS EVENING. SHOULD THEN SEE
GRADUAL IMPROVEMENT AT ALL DENVER AREA TERMINALS AFTER MIDNIGHT
WITH THIS STORM MOVING AWAY FROM THE FRONT RANGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ041.
WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR COZ033>037.
&&
$$
UPDATE...BAKER
SHORT TERM...ENTREKIN
LONG TERM...COOPER
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
405 AM MDT FRI APR 29 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 306 AM MDT FRI APR 29 2016
WATER VAPOR IMAGERY SHOWING ELONGATED UPPER LOW FROM EASTERN UTAH
TO NORTHWEST NEW MEXICO. PRECIPITATION HAS BEEN SLOW TO DEVELOP
ESPECIALLY NORTHERN SECTIONS OF THE CWA. THERE HAS BEEN A GENERAL
NORTHWARD SPREAD OF THE PRECIP WITH MAINLY SNOW FROM DENVER
SOUTHWARD. FURTHER NORTH TEMPERATURES ARE A BIT HIGHER SO LIGHT
RAIN AND DRIZZLE CONTINUE TO FALL FROM BOULDER NORTHWARD. EVEN
WITH THE HEAVIER PRECIP SHOWN ON RADAR...OBSERVATIONS SITES AT
DENVER ARE ONLY SHOWING LIGHT SNOW. PART OF THE PROBLEM IS THE
LIGHT SOUTHEAST FLOW WHICH IS DOWNSLOPING OVER THE FRONT RANGE SO
ONLY A VERY WEAK UPSLOPE COMPONENT. WE ALSO HAVE E A STRONG
SOUTHERLY MID LEVEL FLOW WHICH ALSO MAY BE LIMITING PRECIP. EVEN
NOW THERE APPEARS TO BE DRYING OR DIMINISHMENT OF PRECIP OVER THE
PALMER DIVIDE. LATEST HRRR PICKS UP ON THIS SO A LULL IN THE
PRECIP EARLY THIS AM BEFORE BECOMING WIDESPREAD AGAIN BY LATER BY
LATER THIS MORNING.
AS FOR THE WINTER HILITES...AM CONCERNED THAT WILL NOT BE ABLE TO
MAKE SNOWFALL CRITERIA IN THE MOUNTAINS AND FOOTHILLS. HAVE
LOWERED AMOUNTS....AND TOTAL VALUES LOOK NOW TO BE AROUND 4 TO 9
INCHES ALONG EAST5 SLOPES AND 4 TO 6 INCHES OVER THE PALMER
DIVIDE. THERE JUST DOES NOT SEEM TO BE ENOUGH STRONG UPSLOPE FLOW
DUE TO THE ELONGATED UPPER LOW AND NOT A NICE COMPACT SYSTEM. FOR
NOW WILL LEAVE THE HILITES AS THE BEST POTENTIAL IS STILL TO COME
FOR THIS AFTERNOON. DAY SHIFT MAY DECIDE TO CANCEL HILITES IF
THINGS DON`T COME TOGETHER. OVERALL...HEAVIEST QPF AMOUNTS WILL BE
OVER THE EASTERN PLAINS OF COLORADO WITH LESSER AMOUNTS FURTHER
WEST.
THE UPPER LOW IS PROGGED TO CONSOLIDATE A BIT BETTER BY LATER
THIS AFTERNOON OVER SOUTHEAST COLORADO WHICH LOOKS TO SHOW THE
BEST POTENTIAL FOR PRECIP UNDER THE STRONGEST QG ASCENT.
TEMPERATURES WILL HOVER IN THE LOWER TO MID 30S TODAY AND GIVEN
HIGH SUN ANGLES...MOST OF THE SNOW WILL MELT ON PAVEMENT SURFACES
BUT STILL SOME LIGHT ACCUMULATIONS ON GRASSY SURFACE. LOOK FOR
GRADUAL IMPROVEMENT LATER THIS EVENING AND OVERNIGHT AS THE UPPER
LOW MOVES INTO CENTRAL KANSAS BY LATER TONIGHT. THERE WILL STILL
BE A FAIR AMOUNT OF WRAP AROUND PRECIP OVER FAR NORTHEAST PLAINS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 306 AM MDT FRI APR 29 2016
ON SATURDAY...THE UPPER LOW WILL BE MOVING INTO SOUTHWESTERN
NEBRASKA WITH MOISTURE WRAPPING AROUND THE SYSTEM AND MOVING
ACROSS THE NORTHEAST PLAINS. HIGHEST POPS WILL BE NORTH AND EAST
OF DENVER...WITH THE BEST CHC OF ACCUMULATING SNOWFALL...ALBEIT
LIGHT...IN THE MORNING. AS THE SYSTEM CONTINUES TO TRACK TO THE
NORTHEAST SATURDAY AFTN/EVNG...THE MDLS SHOW WEAK DOWNWARD QG
OVER THE CWA. NAM12 SPATIAL CROSS SECTIONS MAINTAIN A WEAK ELY
FLOW BLO 700 MB SATURDAY NIGHT...BUT MUCH DRIER ALOFT. BEST CHC OF
PCPN WILL BE IN AND NEAR THE FRONT RANGE FOOTHILLS SATURDAY NIGHT
INTO SUNDAY MORNING. WITH THE DRIER AIR ALOFT...COULD SEE PATCHY
FREEZING DRIZZLE DEVELOP SO WILL THROW A LITTLE BIT OF THAT INTO
THE GRIDS. SUNDAY AFTERNOON INTO MONDAY MORNING...ANOTHER CLOSED
PACIFIC SYSTEM AROUND THE FOUR CORNERS REGION AT 18Z SUNDAY IS
PROGGED TO OPEN UP AND MOVE INTO NEBRASKA BY 18Z MONDAY. THIS
SYSTEM IS FAIRLY WEAK...BUT IT DOES HAVE SOME QG ASCENT IN THE MID
LEVELS AND DOES DEEPEN THE MOISTURE ALONG THE FRONT RANGE.
THEREFORE COULD SEE ANOTHER CHANCE OF PCPN...ESPECIALLY FROM THE
URBAN CORRIDOR WESTWARD. TEMPERATURES WILL MODIFY FURTHER ON
TUESDAY BUT AN INTERESTING FEATURE DOES SHOW UP ON THE ECMWF. A
LOW PRESSURE SYSTEM OVER SERN MT/WRN NORTH DAKOTA AROUND 18Z
MONDAY IS PROGGED SLIDE NORTHEAST TO SOUTHWEST AROUND AN OMEGA
RIDGE SITTING OVER THE NRN ROCKIES...AND INTO NWRN CO BY 18Z
TUESDAY. THIS COULD BRING A CHC OF PCPN TO THE REGION TUESDAY
AFTN/EVNG. THE GFS ON THE OTHER HAND SHOWS NO SUCH FEATURE...SO
MAINLY CHC POPS MAINLY OVER THE HIGHER TERRAIN AT THAT TIME. TREND
FOR DRIER AND WARMER STILL ON TRACK FOR THE REST OF THE WEEK WITH
AN UPPER LEVEL RIDGE THE PREVAILING FEATURE FOR WEDNESDAY AND
THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 306 AM MDT FRI APR 29 2016
LIGHT SNOW CONTINUES AT THE TERMINALS BUT COULD BE A LULL IN THE
SNOWFALL BETWEEN 11-14Z AS RADAR SHOWING SOME DRYING OVER THE
PALMER DIVIDE. MOST WIDESPREAD PRECIP WILL BE FROM LATER THIS AM
THROUGH THE AFTERNOON AS THE UPPER LOW APPROACHES SOUTHEAST
COLORADO. GRADUAL DIMINISHMENT IN PRECIP BY LATER THIS EVENING AND
OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ041.
WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR COZ033>037.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM...COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
635 PM EDT FRI APR 29 2016
.SYNOPSIS...
A WEAK SYSTEM MOVES ACROSS OUR AREA THROUGH THIS EVENING, THEN HIGH
PRESSURE BUILDS DOWN FROM THE NORTH SATURDAY. LOW PRESSURE IS
FORECAST TO TRACK ACROSS OUR AREA SUNDAY INTO EARLY MONDAY BEFORE
SHIFTING OFFSHORE DURING MONDAY. HIGH PRESSURE MAY EXTEND INTO OUR
AREA TUESDAY INTO WEDNESDAY. AS LOW PRESSURE TRACKS NORTHWARD
OFFSHORE THURSDAY INTO FRIDAY, A COUPLE OF COLD FRONTS ARE FORECAST
TO APPROACH OR MOVE THROUGH OUR AREA.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
CLOUD COVER IS KEEPING TEMPS WELL BELOW NORMAL IN THE LOWER 50S.
THIS BASIC PATTERN WILL NOT CHANGE MUCH THROUGH TONIGHT AND
TOMORROW ALTHOUGH SOMEWHAT DRIER AIR IS EXPECTED TO PUSH IN FROM
THE NORTH FOR A WHILE ON SATURDAY.
FOR TONIGHT...A SHORTWV TROF NOW LOCATED APPROX OVER LAKE ERIE WILL
MOVE ESE ACROSS THE AREA WITH SOME WEAK LOW-LEVEL WARM ADVECTION AND
UVV AHEAD OF IT. THIS WILL RESULT IN INCREASE SHOWERS AS CAN ALREADY
BE SEEN ON THE REGIONAL RADAR LOOP. INDICATIONS ARE THAT THE MOST
CONCENTRATED SHOWER ACTIVITY WILL BE ACROSS THE POCONOS, LEHIGH VLY
AND NORTHERN NJ. PRECIP AMOUNTS SHOULD BE SOMEWHAT HIGHER THERE ALSO
ALTHOUGH PROBABLY NO MORE THAN ONE-QUARTER INCH OR SO...WITH LESSER
AMOUNTS FOR PHL AND SOUTH. THE SHOWERS SHOULD TAPER OFF SHORTLY
AFTER MIDNIGHT. COOLING OVERNIGHT WILL BE LIMITED BY THE CLOUD COVER
AND LOWS IN THE LOW TO MID 40S ARE EXPECTED.
HAVE LOWERED POPS CONSIDERABLY OVER SRN AND WRN SECTIONS AT LEAST
FOR THE NEXT FEW HOURS BASED ON RADAR TRENDS AND THE HRRR GUID.
POPS SHUD BE ZERO OR CLOSE TO IN THESE AREAS. OTHERWISE MADE SOME
MINOR TWEAKS TO TEMPS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
FOR SATURDAY...WEAK HIGH PRESSURE WILL BUILD IN FROM THE NORTH AND
THERE WILL ALSO BE SOME RIDGING ALOFT BEHIND THE SHRTWV TROF. A
DRIER AIRMASS WILL BE IN PLACE PROVIDING CONSIDERABLY MORE SUNSHINE
THAN TODAY. THUS DAYTIME HEATING WILL ALLOW FOR MILDER AFTERNOON
TEMPS ON SATURDAY WITH HIGHS IN THE LOW 60S...EXCEPT COOLER NEAR THE
ATLANTIC COAST SINCE WINDS WILL STILL BE COMING OFFER THE OCEAN.
SOME MID TO HIGH-LEVEL CLOUDS WILL BE SPREADING IN FROM THE SW IN
THE AFTERNOON AHEAD OF THE NEXT SYSTEM. HOWEVER THE ASSOCD PRECIP
SHOULD NOT REACH THE AREA UNTIL AFTER DARK.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE SYNOPTIC PATTERN IS FORECAST TO BE COMPRISED OF A RIDGE THAT
QUICKLY SLIDES ACROSS THE EAST SATURDAY NIGHT. PLENTY OF ENERGY
STRETCHES FROM THE GREAT LAKES BACK INTO THE FOUR CORNERS AREA, AND
THE UPPER-LEVEL FLOW ACROSS THE EAST BACKS TO MORE SOUTHWESTERLY. AS
THE NORTHERN PORTION OF A TROUGH AMPLIFIES ACROSS THE GREAT LAKES
SUNDAY NIGHT INTO MONDAY THEN EASTWARD DURING MONDAY, LOW PRESSURE
TRACKS FROM THE PLAINS TO THE UPPER OHIO VALLEY THEN ACROSS OUR
REGION. THERE LOOKS TO BE PLENTY OF MOISTURE TRANSPORT AHEAD OF AND
WITH THIS FEATURE, WHICH SHOULD RESULT IN A DECENT AMOUNT OF
RAINFALL FROM LATE SATURDAY NIGHT INTO MONDAY. THE TROUGH THEN LIFTS
OUT THEREAFTER, HOWEVER A MORE SIGNIFICANT TROUGH IS FORECAST TO
AMPLIFY INTO THE EAST WEDNESDAY AND THURSDAY. WHILE SOME INDIVIDUAL
MODEL RUNS SHOW THE POTENTIAL FOR THE UPPER-LEVEL TROUGH TO CLOSE
OFF FRIDAY SOMEWHERE OVER THE EASTERN STATES, THERE IS A LACK OF
CONSISTENCY/AGREEMENT. THIS WOULD RESULT IN COOLER AND MORE
UNSETTLED WEATHER ACROSS THE EAST. WE USED A MODEL/CONTINUITY BLEND
INTO MONDAY, THEN BLENDED IN THE 12Z WPC GUIDANCE THEREAFTER. SOME
ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH
OUR NEIGHBORING OFFICES.
FOR SATURDAY NIGHT AND SUNDAY...AS AN UPPER-LEVEL RIDGE AXIS QUICKLY
SHIFTS TO OUR EAST SATURDAY NIGHT, SURFACE HIGH PRESSURE ALSO EASES
OFFSHORE. ON ITS HEELS IS ENERGY EJECTING OUT OF THE PLAINS WITHIN A
BACKING UPPER-LEVEL FLOW. THIS WILL RESULT IN INCREASING DOWNSTREAM
WAA AND MOISTURE ADVECTION ALONG WITH ISENTROPIC LIFT. AS A RESULT,
WE ARE ANTICIPATING RAIN OVERSPREADING THE ENTIRE REGION BY LATE
SATURDAY NIGHT WITH IT CONTINUING FOR MUCH OF SUNDAY. THE MODEL
GUIDANCE SHOWS THE PW VALUES SURGING INTO THE 1.0-1.5 INCH RANGE
THROUGH SUNDAY. THIS COMBINED WITH AMPLE LIFT MAY ALLOW THE RAIN TO
BE MODERATE/HEAVY AT TIMES. RAINFALL AMOUNTS BY LATE SUNDAY OF
AROUND AN INCH ARE POSSIBLE FOR MUCH OF THE AREA, HOWEVER THIS
SHOULD FALL OVER A LONG ENOUGH PERIOD OF TIME. THE FORECAST
SOUNDINGS OVERALL INDICATE A PRONOUNCED VEERING PROFILE IN THE LOWER
LEVELS AS A LOW-LEVEL JET MOVES THROUGH DURING A PORTION OF SUNDAY.
THE LEADING EDGE OF THE WAA SURGE AND INCREASING 850 MB FLOW COULD
ALLOW THE RAIN TO RAMP UP QUICKLY TOWARD 12Z SUNDAY. DESPITE THE
SHOWERY WEATHER OF LATE, THE REGION COULD USE MORE RAIN.
THERE IS ALSO AT LEAST SOME INSTABILITY FORECAST SUNDAY AFTERNOON
AND EVENING MAINLY SOUTH OF PHILADELPHIA. THIS WILL BE DETERMINED BY
HOW FAR NORTH THE INCOMING WARM FRONT GETS. GIVEN THE FORECAST ATTM,
WE KEPT A MENTION OF SOME THUNDER ACROSS THE SOUTHERN ZONES SUNDAY
AFTERNOON INTO THE EVENING. THE BEST ISENTROPIC LIFT MAY START TO
SHIFT TO OUR NORTHEAST BY SUNDAY AFTERNOON AND EVENING, ALLOWING THE
STEADY RAIN TO END AND BECOME MORE SHOWERY. THIS OCCURS AS SURFACE
LOW PRESSURE ARRIVES RIGHT OVER OUR AREA BY DAYBREAK MONDAY.
FOR MONDAY AND TUESDAY...AS AN UPPER-LEVEL TROUGH AMPLIFIES ACROSS
THE NORTHEAST AND MID ATLANTIC REGIONS MONDAY, SURFACE LOW PRESSURE
WILL BE SHIFTING OFFSHORE. WHILE MONDAY IS LOOKING DRIER WITH TIME
AS THE SURFACE LOW DEPARTS, RESIDUAL MOISTURE AND LIFT WITH THE
INCOMING TROUGH SHOULD PRODUCE SHOWERS ESPECIALLY THE FIRST HALF OF
THE DAY. IT APPEARS THE WARM SECTOR IS IN OUR SOUTHERN AREAS MONDAY
BEFORE THE SURFACE LOW SHIFTS OFFSHORE. WHILE SOME THUNDER CANNOT BE
RULED OUT WITHIN THE WARM SECTOR, THE SURFACE LOW IS FORECAST TO
EXIT TO THE EAST DURING THE FIRST PART OF MONDAY. GIVEN LESS
CERTAINTY FOR SOME THUNDER MONDAY, WE OPTED TO NOT INCLUDE A
MENTION. ANY LEFTOVER SHOWERS SHOULD END EARLY MONDAY NIGHT AS THE
TROUGH AXIS SHIFTS OFFSHORE AND THE LOW-LEVEL FLOW TURNS MORE FROM
THE NORTH AND NORTHWEST. A WEAK AREA OF HIGH PRESSURE MAY THEN
EXTEND INTO OUR AREA FROM THE WEST TUESDAY.
FOR WEDNESDAY THROUGH FRIDAY...AN UPPER-LEVEL TROUGH IS FORECAST TO
AMPLIFY INTO THE EAST DURING THIS TIME FRAME. AS THIS STARTS TO
OCCUR, A FRONTAL BOUNDARY TO OUR SOUTH AND EAST MAY HAVE A WAVE OF
LOW PRESSURE RUNNING UP THE FRONT. THIS COULD AT LEAST BRUSH OUR
EASTERN AND SOUTHERN ZONES WEDNESDAY, HOWEVER THERE IS LOW
CONFIDENCE WITH THIS. AS THE MAIN TROUGH TO OUR WEST ARRIVES
THURSDAY, A SURFACE COLD FRONT WILL ALSO ARRIVE AND MOVE THROUGH.
THE WAA AHEAD OF THE FRONT SHOULD ALLOW FOR WARMER TEMPERATURES
WEDNESDAY AND THURSDAY BEFORE SOME COOLING TAKES PLACE ON FRIDAY.
THE COOLING ON FRIDAY MAY ALSO BE ACCOMPANIED BY A SECONDARY COLD
FRONT APPROACHING. THE SETUP FOR THURSDAY INTO FRIDAY COULD BE MORE
UNSETTLED AS ENERGY OFF THE COAST ALONG AN OLD FRONT MAY ALLOW FOR A
STRENGTHENING SURFACE LOW. THIS FEATURE, DEPENDING ON ITS TRACK AND
ALSO STRENGTH/POSITION OF THE UPPER-LEVEL TROUGH, COULD ENHANCE
PRECIPITATION OVER OUR AREA THURSDAY INTO FRIDAY ALONG WITH AN
INCOMING COLD FRONT FROM THE WEST. GIVEN THE UNCERTAINTY ON THE
SYNOPTIC EVOLUTION AND ASSOCIATED DETAILS, WE KEPT POPS NO HIGH THAN
CHC.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG,KMIV, KACY AND SURROUNDING AREAS.
DETERIORATING CONDITIONS ARE EXPECTED FOR ALL TAF SITES INTO THIS
EVENING. CEILINGS HAVE ALREADY FALLEN INTO THE MVFR RANGE FOR MOST
SITES. THEY WILL CONTINUE TO DROP THROUGH THIS EVENING AND MAY
REACH IFR ESPECIALLY PHL AND SOUTH. CONFIDENCE IS NOT VERY HIGH ON
OCCURRENCE OR TIMING OF IFR. HOWEVER IF IFR CIGS DO DEVELOP THEY
MAY LAST FOR MOST OF THE NIGHT EVEN THOUGH THE MOS GUIDANCE
SUGGEST SOME IMPROVEMENT AFTER MIDNIGHT. VSBY SHOULD NOT BE TOO
MUCH OF AN ISSUE ALTHOUGH COULD BE TEMPORARILY REDUCED IN SHOWERS
THIS EVENING. CONDITIONS WILL IMPROVE TO VFR SAT MORNING AND
CONTINUE THROUGH THE DAY. WINDS WILL REMAIN LIGHT OVERALL.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY...THE CONDITIONS LOWER TO MVFR/IFR
SATURDAY NIGHT AND SUNDAY WITH PERIODS OF RAIN, THEN IMPROVE LATER
MONDAY WITH SOME SHOWERS STILL EXPECTED DURING MONDAY. A FEW
THUNDERSTORMS ARE POSSIBLE SUNDAY AFTERNOON AND EVENING, MAINLY
SOUTH OF KPHL. EAST OR SOUTHEAST WINDS 10 KNOTS OR LESS.
TUESDAY AND WEDNESDAY...VFR OVERALL AS WEAK HIGH PRESSURE ARRIVES.
&&
.MARINE...
NORTHEAST WIND WITH A FAIRLY LONG FETCH IS BLOWING INTO THE NJ
COASTAL WATERS. THIS RESULTS IN BUILDING SEAS WHICH HAVE REACHED 5
TO 6 FEET AT BUOYS 44009...91 AND 65. HIGHER SEAS ARE EXPECTED TO
CONTINUE THROUGH TONIGHT HENCE A SCA FOR HAZ SEAS HAS BEEN EXTENDED
UNTIL 600 AM SAT. THIS SCA MAY NEED TO BE EXTENDED FURTHER INTO THE
DAY ON SAT.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY...NORTHEAST WINDS MAY BRIEFLY GUST TO
25 KNOTS ACROSS MAINLY THE NORTHERN ATLANTIC COASTAL WATERS SUNDAY
AHEAD OF LOW PRESSURE. WHILE SEAS SHOULD BE MOSTLY IN THE 2-4 FOOT
RANGE, TIMES OF 5 FOOTERS ARE POSSIBLE ON THE ATLANTIC COASTAL
WATERS.
TUESDAY AND WEDNESDAY...THE WINDS SHOULD BE BELOW SMALL CRAFT
ADVISORY CRITERIA, HOWEVER SEAS COULD BUILD TO 5 ABOUT FEET DURING
WEDNESDAY ON THE ATLANTIC COASTAL WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT
SATURDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...AMC/NIERENBERG
SHORT TERM...AMC
LONG TERM...GORSE
AVIATION...AMC/GORSE
MARINE...AMC/GORSE
AREA FORECAST DISCUSSION
NWS KEY WEST FL
930 PM EDT SAT APR 30 2016
.DISCUSSION...IN THE MID AND UPPER LEVELS...700-200 MB...LATEST
AVAILABLE IR IMAGERY AS OF 900 PM...OVERLAID WITH MODEL STREAMLINE
ANALYSIS DEPICT SEVERAL LOW PRESSURE GYRES OVER THE WESTERN AND
CENTRAL CONUS...WITH UPPER RIDGING ACROSS THE EASTERN CONUS. A 75 TO
100 KNOT SOUTHERN STREAM OF THE JET AT 250 MB EXTENDS FROM BAJA
CALIFORNIA EASTWARD TO ACROSS TEXAS THENCE NORTHEAST TO NEW ENGLAND.
WELL TO THE SOUTH OF THAT...SOUTH FLORIDA AND THE KEYS ARE BENEATH
THE NORTHEAST PERIPHERY OF DEEP MIDDLE AND UPPER RIDGING CENTERED
OVER CENTRAL AMERICA...WITH ONLY HIGH LEVEL CIRRUS IS MOVING ACROSS
THE AREA.
AT THE SURFACE AND IN THE LOWER TO MIDDLE LEVELS...SURFACE TO 700
MB...LATEST IR IMAGERY OVERLAID WITH LATEST AVAILABLE LAND AND
MARINE SURFACE OBSERVATIONS AND ANALYSIS AS OF 900 PM DETAIL A COLD
FRONT EXTENDING INTO DEEP SOUTH TEXAS FROM LOW PRESSURE OVER
NORTHERN MISSOURI. CLOSER TO THE KEYS...SURFACE RIDGING IS PARKED
OVER THE MID-ATLANTIC STATES. AS A RESULT THE 00Z SOUNDING AT KEY
WEST ILLUSTRATED GENTLE TO FRESH EAST WINDS UP TO 900 MB...THEN
GENTLE ABOVE THAT...WITH (PWAT AT .80 INCHES) AND AN INVERSION ABOVE
900 MB AND VERY DRY AIR ABOVE THAT.
.CURRENTLY...AS OF 900 PM...SKIES ARE PARTLY CLOUDY ACROSS THE
ISLANDS AND SURROUNDING WATERS OWING MOSTLY TO CIRRUS. TEMPERATURES
ACROSS THE ISLAND CHAIN ARE IN THE UPPER 70S WITH DEWPOINTS IN THE
UPPER 60S. C-MAN STATIONS ALONG THE FLORIDA REEF ARE REGISTERING
EAST WINDS BETWEEN 15 AND 20 KNOTS...AND 15 KNOTS IN FLORIDA
BAY...WITH SMITH SHOAL RECORDING 15 TO 20 KNOTS AS WELL.
.SHORT TERM...OVERNIGHT...COMBINATION OF DEVELOPING LOW PRESSURE
ALONG AFOREMENTIONED COLD FRONT OVER THE MIDDLE SOUTH...WITH
SURFACE RIDGING OVER THE MID ATLANTIC STATES WILL ALLOW FOR A SURGE
IN THE BREEZE FOR THE FIRST PART OF THE OVERNIGHT PERIOD. THIS IS
INDICATED IN THE LATEST HRRR AND HINTED AT IN THE LAST FEW HOURS OF
SAND KEY OBS. WILL JUST DO A MINOR UPDATE IN BOTH ZONES AND COASTALS
IN INCLUDE BREEZY CONDITIONS ACROSS THE ISLANDS...WITH 15 TO 20 MPH.
&&
.MARINE...OVERNIGHT...WILL SEE A GOOD PORTION OF THE STRAITS INCREASE
TO NEAR 20 KNOTS FOR MOST OF THE STRAITS THROUGH THE REST OF THIS
EVENING AND FOR SEVERAL HOURS AFTER MIDNIGHT. SMALL CRAFT WILL STILL
NEED TO EXERCISE CAUTION ACROSS THE REST OF THE MARINE DISTRICT
EXCEPT FLORIDA BAY AND THE SHALLOW WATERS INSIDE THE FIVE FATHOM
LINE. THEREAFTER...A LULL IS EXPECTED SUNDAY...BUT WILL PICK UP AGAIN
TO A LESSER EXTENT SUNDAY NIGHT.
&&
.AVIATION...OVERNIGHT...VFR CONDITIONS WILL PREVAIL OVERNIGHT AT THE
KEY WEST AND MARATHON INTL ISLAND TERMINALS. SURFACE WINDS WILL
AVERAGE FROM 100-110 DEGREES AOA 12-14 KTS WITH GUSTS TO AROUND 20
KNOTS. EXPECT FEW-SCATTERED CLOUDS AOA FL030 WITH CIRRUS AOA FL200-
250.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SCA FOR GMZ052-055&GMZ072-075 THRU 10Z.
&&
$$
PUBLIC/MARINE....................FUTTERMAN
AVIATION/NOWCASTS................FUTTERMAN
DATA COLLECTION/UPPER AIR........DEVANAS
VISIT US ON THE WEB AT WEATHER.GOV/KEY
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AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
826 PM EDT SAT APR 30 2016
.AVIATION...
VFR WILL PREVAIL AT ALL TERMINALS WITH BROKEN HIGH CIRRUS
CIGS AOA FL250 PERSISTING THROUGH 14Z. AFTER 14Z DEVELOPING
SCATTERED CU AOA FL040 ALONG WITH SCATTERED CIRRUS AOA
FL250 CAN BE EXPECTED. SOUTHEAST WINDS IN THE 4 TO 6 KNOT
RANGE WILL PREVAIL THROUGH 14Z...BECOMING SOUTHEAST TO SOUTH
AT 6 TO 8 KNOTS BETWEEN 14-18Z. AFTER 18Z SOUTHWEST WINDS
AROUND 10 KNOTS...EXCEPT REMAINING SOUTHEAST AROUND 10 KNOTS
AT KLAL.
&&
.PREV DISCUSSION... /ISSUED 327 PM EDT SAT APR 30 2016/
SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A COMPLEX UPPER LEVEL
PATTERN OVER THE CONUS...HIGHLIGHTED BY LONGWAVE TROUGHING OVER
THE INTER-MOUNTAIN WEST AND CENTRAL PLAINS. WITHIN THIS TROUGH WE
FIND SEVERAL DISTINCT LOBES OF ENERGY/CLOSED LOWS...ONE EJECTING
THROUGH THE CENTRAL PLAINS BRINGING ABUNDANT RAIN/STORMS FROM THE
UPPER WEST TO THE MS VALLEY...AND A SECOND PIVOTING THROUGH THE
FOUR- CORNERS REGION. DOWNSTREAM FROM ALL THIS INCLEMENT
ACTIVITY...THE FLOW RIDGES UP OVER MUCH OF THE EASTERN
SEABOARD...INCLUDING THE FLORIDA PENINSULA. WV IMAGERY DOES SHOW
PLENTY OF HIGH LEVEL MOISTURE ARRIVING OVER THE EASTERN GULF/FL
PENINSULA ALONG THE NOSE OF A SOUTHERN STREAM JETSTREAK. THESE
CLOUDS ARE GENERALLY ABOVE 20-25KFT...AND WILL CONTINUE TO FILTER
THE SUN AT TIMES THROUGH THE REMAINDER OF THE DAY.
DROP BELOW THIS CIRRUS LEVEL AND THE COLUMN OVER THE PENINSULA IS
GENERALLY QUITE DRY. THIS WAS SHOWN NICELY IN THE 30/12Z KTBW
SOUNDING PROFILE. THE SUBSIDENCE INVERSION ASSOCIATED WITH THE
RIDGE OVERHEAD WAS SAMPLED IN THE VICINITY OF 700MB...WITH A
MARKED DROP IN DEWPOINT/RH ABOVE THIS LEVEL.
AT THE SURFACE...HIGH PRESSURE CONTINUES TO RIDGE BACK ACROSS THE
FLORIDA PENINSULA FROM THE WESTERN ATLANTIC. THE PRESSURE GRADIENT
AROUND THIS RIDGE IS PROVIDING A GENERALLY LIGHT SOUTHEAST
SYNOPTIC FLOW. DESPITE THE ABUNDANT HIGH CLOUDS...HAVE STILL
EXPERIENCING SUFFICIENT INSOLATION FOR TEMPERATURE RISE WELL INTO
THE 80S. THE TERRESTRIAL HEATING HAS BROUGHT ON SEA-BREEZE
DEVELOPMENT AND HAVE SEEN MOST COASTAL STATIONS FLIP THEIR WIND
AROUND ONSHORE AND THE PAST COUPLE OF HOURS.
SHORT TERM (THIS EVENING THROUGH SUNDAY)...
NOW THAT THE SEA- BREEZE HAS BEGUN TO MAKE SOME PROGRESS
INLAND...THE POTENTIAL FOR A FEW ISOLATED SHOWERS WILL INCREASE.
MOST SPOTS WILL LIKELY TO REMAIN DRY THE REST OF TODAY...ESPECIALLY
THE FURTHER SOUTH FROM THE I-4 CORRIDOR ONE TRAVELS. THE DRY AIR
AND SUPPRESSION ARE DEEPEST AND STRONGEST OVER THE SOUTHERN HALF
OF THE PENINSULA...AND ANY CONVECTION THAT DOES DEVELOP SHOULD BE
QUITE ISOLATED AND BRIEF IN NATURE. THE ATMOSPHERIC COLUMN IS
SLIGHTLY "MORE FAVORABLE" NORTH OF I-4...BUT "MORE FAVORABLE" IS
STILL NOT FAVORABLE. THERE IS PLENTY OF DRY AIR OVER OUR NORTHERN
ZONES FOR UPDRAFTS TO BATTLE. STILL THE POTENTIAL FOR A FEW
SUSTAINED UPDRAFTS TO THE NORTH AND EAST OF THE TAMPA BAY AREA
DOES EXIST AS WE HEAD DEEPER INTO THE AFTERNOON/EARLY
EVENING...AND CONVERGENCE BETWEEN THE EAST COAST AND WEST COAST
SEA-BREEZE CIRCULATIONS IS AT A MAXIMUM. HAVE ALREADY SEEN A FEW
CONVECTIVE CELLS GO UP TOWARD THE I-10 CORRIDOR AND SHOULD SEE
SOME ADDITIONAL DEVELOPMENT FURTHER SOUTH AFTER 20Z. THIS
POTENTIAL WILL ALSO SHIFT INLAND QUICKLY WITH THE PROGRESSION OF
THE WEST COAST SEA- BREEZE. HAVE GONE WITH A 20-30% POP OVER THE
NORTHERN HALF OF THE AREA...ALTHOUGH ALONG THE COAST...THE RAIN
CHANCES ONLY BRIEFLY OCCUR LATE THIS AFTERNOON...AND THEN DECREASE
BY EARLY EVENING BEHIND THE SEA- BREEZE.
TONIGHT...FEW ISOLATED MID EVENING SHOWERS ALONG AND NORTH OF THE
I-4 CORRIDOR SHOULD DISSIPATE WITHIN A COUPLE HOUR OF SUNSET...AND
SET UP A DRY AND SEASONABLY WARM OVERNIGHT PERIOD. WINDS WILL
RETURN TO THE SOUTHEAST AS THE SEA-BREEZE SHUTS DOWN AND BECOME
LIGHT BY LATE EVENING. VERY PROBABLE TO SEE A FEW FOGGY PATCHES
ACROSS THE NATURE COAST TOWARD DAWN...HOWEVER NO SIGNIFICANT FOG
OR VISIBILITY PROBLEMS ARE ANTICIPATED.
SUNDAY... MORE OF THE SAME FOR THE SECOND HALF OF THE WEEKEND.
ALTHOUGH THE UPPER RIDGE AXIS SHIFT A BIT TO THE EAST...OVERALL
THE SYNOPTIC SETUP IS VERY SIMILAR TOMORROW. PLENTY OF DRY MID-
LEVEL AIR TO CONTEND WITH...WITH THE GREATEST SUPPRESSION AND MOST
HOSTILE ENVIRONMENT TOWARD DEEP CONVECTION EXISTING OVER THE
SOUTHERN HALF OF THE FORECAST AREA. WITH THE NOSE OF THE SOUTHERN
STREAM JET NEARBY...WOULD ANTICIPATE BOUTS OF HIGH LEVEL CIRRUS
CONTINUING TO INVADE OUR SKIES AND FILTER THE SUN FROM TIME TO
TIME. ALTHOUGH IF UPPER LEVEL MOISTURE AND LIFT FIELDS FORECAST BY
MOST OF THE NWP MEMBERS ARE CORRECT...THE DEGREE OF HIGH CLOUDS
WILL BE LESS THAN HAS BEEN SEEN MOST OF TODAY. FOR THAT
REASON...THINK WE CAN STILL CALL IT A MIX OF SUN AND CLOUDS. ONCE
THE SEA- BREEZE FORMS...A FEW ISOLATED SHOWERS CAN BE EXPECTED
AWAY FROM THE COAST...MAINLY NORTH OF THE I-4 CORRIDOR.
HOWEVER...COVERAGE OF ANY SHOWERS WILL NOT BE GREAT AND SHOULD
HAVE LIMITED (IF ANY) IMPACT TO PLANNED OUTDOOR ACTIVITIES.
MID/LONG TERM (MONDAY THROUGH NEXT SATURDAY)...
THE WORK WEEK STARTS WITH CONTINUED ABOVE AVERAGE TEMPERATURES
ACROSS THE AREA AND AFTERNOON RAIN CHANCES IN ASSOCIATION WITH
SEABREEZE ACTIVITY. AS WE PROGRESS INTO TUESDAY AND WEDNESDAY RAIN
CHANCES WILL BE ON THE INCREASE AS AN APPROACHING FRONTAL BOUNDARY
WILL BEGIN TO PUSH INTO THE DEEP SOUTH. AHEAD OF THIS FRONT WE WILL
SEE A SURGE IN ATMOSPHERIC MOISTURE WITH PWATS INCREASING IN EXCESS
OF 1.5 INCHES ACROSS MUCH OF THE AREA. THIS SHOULD ALLOW FOR A MORE
WIDESPREAD AFTN SEABREEZE ACTIVITY ON TUESDAY WITH HIGHEST CHANCES
ACROSS THE INTERIOR PORTIONS OF THE FORECAST AREA.
THE AFOREMENTIONED FRONT WILL THEN PUSH THROUGH THE AREA DURING THE
DAY ON WEDNESDAY. EARLIER RUNS OF THE ECMWF DEPICTED A STRONG
SHORTWAVE MOVING ACROSS NORTH FLORIDA WHICH WOULD HAVE AIDED IN
SETTING THE STAGE FOR A DECENT SEVERE WEATHER EVENT. HOWEVER...THE
MOST RECENT 12Z RUN OF THE ECMWF HAS COME IN LINE MORE WITH THE GFS
SOLUTION WHICH SHOWED A MUCH MORE LIMITED SEVERE THREAT COMPARED TO
THE 00Z ECMWF. THAT BEING SAID...THE POTENTIAL STILL EXISTS FOR A
STRONGER STORM OR TWO ON WEDNESDAY WITH INCREASED FRONTAL
CONVERGENCE AND LOCAL BOUNDARY INTERACTIONS.
AFTER THE FRONT PUSHES THROUGH...MUCH DRIER AND SLIGHTLY COOLER AIR
WILL INFILTRATE THE PENINSULA FOR THE REST OF THE WEEK AND INTO NEXT
WEEKEND. AFTERNOON HIGH TEMPERATURES WILL RETURN CLOSER TO
CLIMATOLOGY (LOW TO MID 80S) AND MUCH COOLER OVERNIGHT...COMPARED TO
EARLIER IN THE WEEK...WITH OVERNIGHT LOWS IN THE UPPER 50S ACROSS
THE NORTH AND LOWER 60S ELSEWHERE.
MARINE... A RIDGE OF WEAK HIGH PRESSURE WILL RESIDE ACROSS
FLORIDA AND THE EASTERN GULF OF MEXICO THROUGH THE EARLY PART OF
THE WEEK...THEN SLIDE EAST AS A COLD FRONT APPROACHES WEDNESDAY
INTO THURSDAY. NO SIGNIFICANT MARINE HAZARDS ARE ANTICIPATED
BEFORE THE APPROACH OF THIS MID-WEEK FRONT.
FIRE WEATHER...
HIGH PRESSURE WILL CONTINUE TO CONTROL OUR WEATHER THROUGH THE
EARLY PORTION OF THE WEEK. NO SIGNIFICANT FIRE WEATHER CONCERNS
ARE ANTICIPATED THE NEXT SEVERAL DAYS AS RELATIVE HUMIDITY
VALUES REMAIN ABOVE CRITICAL LEVELS...AND WINDS REMAIN GENERALLY
LIGHT. ALTHOUGH A FEW ISOLATED TO SCATTERED SHOWERS ARE POSSIBLE
THE NEXT FEW AFTERNOONS...THE NEXT POTENTIAL FOR WIDESPREAD
WETTING RAINS WILL NOT ARRIVE UNTIL THE PASSAGE OF A COLD FRONT
WEDNESDAY OR WEDNESDAY NIGHT.
FOG POTENTIAL...PATCHY FOG POSSIBLE EARLY SUNDAY MORNING ACROSS
THE NATURE COAST...HOWEVER NO SIGNIFICANT AREAS OF FOG OR
VISIBILITY RESTRICTIONS ARE ANTICIPATED THROUGH THE REMAINDER
OF THE WEEKEND.
PRELIMINARY POINT TEMPS/POPS...
TPA 72 89 73 88 / 10 0 10 20
FMY 69 89 71 90 / 0 10 10 20
GIF 69 91 70 90 / 20 10 10 30
SRQ 70 82 70 85 / 0 10 0 20
BKV 67 89 66 89 / 20 10 10 30
SPG 73 86 73 88 / 0 0 0 20
TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
$$
AVIATION...57/MCMICHAEL
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
937 AM EDT FRI APR 29 2016
.UPDATE...
TODAY-TONIGHT...MORNING SOUNDINGS ACROSS CENTRAL FLORIDA SHOW A
LITTLE HIGHER PRECIPITABLE WATER THAN YESTERDAY...1.35 TO 1.48
INCHES. TEMPERATURE PROFILE (MINUS 9-10 CELSIUS AT 500MB) LOOKS
SIMILAR TO YESTERDAY. EARLY MORNING SURFACE DEW POINTS ARE HIGHER
THAN YESTERDAY...UPPER 60S WITH A FEW READINGS EVEN IN THE LOWER
70S. HIGH TEMPERATURES ARE PROGGED TO REACH THE UPPER 80S...WITH
SOME LOWER 90S OVER THE INTERIOR. THIS SETUP REFLECTS A TYPICAL PRE-
CONVECTIVE SEASON COVERAGE OF SHOWERS AND STORMS...30 PERCENT OR
LESS.
SOUNDINGS AND CANAVERAL PROFILERS SHOW LOW LEVEL WINDS 10 KNOTS OR
LESS THEN GRADUALLY VEERING AND BECOMING NORTHWEST/NORTH IN THE MID
LEVELS. THE HRRR HAS BEEN SHOWING SEA BREEZE DRIVEN CONVECTION
FAVORING THE SOUTH HALF OF THE AREA...STARTING BY EARLY AFTERNOON.
WHILE THE GFS SUPPORTS THIS...ADDITIONAL DEVELOPMENT IS ALSO
INDICATED ACROSS THE NORTH INTERIOR AS THE EAST/WEST COAST
BOUNDARIES COLLIDE LATE IN THE DAY.
ONE THING NOTED IN THE MORNING SOUNDING IS A DRY LAYER AT A FEW
THOUSAND FEET. THIS USUALLY DELAYS ONSET OF CONVECTION AND LIMITS
COVERAGE...SO COASTAL POPS AT 20 PERCENT LOOK OKAY. STRONGEST
BOUNDARY INTERACTIONS WILL BE ACROSS THE INTERIOR BY EARLY
EVENING...SO WOULD EXPECT SLIGHTLY HIGHER POPS AROUND 30 PERCENT
THERE. WITH MID LEVEL FLOW COMING AROUND MORE TO THE NORTH...THERE
PROBABLY WILL NOT BE MUCH PUSH BACK TO THE COAST OF THE EVENING
CONVECTION.
LITTLE CHANGE TO THE CURRENT FORECAST IS EXPECTED.
&&
.AVIATION...
AREA OF FOG/LOW STRATUS IS STARTING TO DIMINISH AROUND KLEE.
ELSEWHERE...IT WILL BE VFR THIS MORNING EXCEPT THERE IS A
POSSIBILITY OF LOCAL/BRIEF MVFR CEILINGS AS DAYTIME HEATING CLOUDS
FORM. COVERAGE OF AFTERNOON-EVENING THUNDERSTORMS LOOKS LOW ALONG
THE COAST SO CANNOT INCLUDE MENTION IN THE TAFS...THOUGH SHORT
DURATION TEMPO GROUPS ARE POSSIBLE ONCE CONVECTION INITIATES. THE
SAME GOES FOR THE INTERIOR THOUGH COVERAGE WILL BE A BIT HIGHER THAN
THE COAST.
&&
.MARINE...
TODAY...AXIS OF THE HIGH PRESSURE RIDGE WILL SHIFT TO OUR SOUTH AS A
WEAK FRONTAL TROUGH PUSHES OFF THE GEORGIA COAST. THE RESULTING
LIGHT OFFSHORE WIND FLOW THIS MORNING WILL TURN ONSHORE THIS AFTN IN
A SEA BREEZE. SEAS NEAR 2 FEET. ISOLATED SEA BREEZE STORMS NEAR THE
COAST EARLY-MID AFTERNOON WILL PROPAGATE INLAND AND AWAY FROM THE
COAST.
TONIGHT...WIND FLOW BECOMES LIGHT SOUTHEAST 5 TO 10 KNOTS AS HIGH
PRESSURE BUILDS OVER THE ATLANTIC.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...LASCODY
IMPACT WX....BRAGAW
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
939 PM EDT SAT APR 30 2016
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE AREA TONIGHT AS A STATIONARY
FRONT TO THE NORTH TODAY LIFTS NORTH. LOW PRESSURE WILL PASS FAR
TO THE NORTH SUNDAY AND MONDAY. ANOTHER AREA OF LOW PRESSURE IS
EXPECTED TO DEVELOP OVER OR JUST NORTH OF THE AREA TUESDAY AND
WEDNESDAY. HIGH PRESSURE WILL BUILD BACK INTO THE AREA BY THE END
OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE 00Z SOUNDING FROM KCHS SHOWED PLENTY OF DRY/STABLE AIR ALOFT
WHICH HAS BEEN ANCHORED ACROSS MUCH OF THE FORECAST AREA TODAY.
LATEST RAP ANALYSIS SHOWS A RING OF DEEPER MOISTURE AND
INSTABILITY WHICH EXTENDS FROM AROUND VALDOSTA GA TO ATLANTA AND
CHARLOTTE EARLY THIS EVENING. THIS LINES UP WELL WITH CONVECTIVE
RAINS WHICH HAVE BEEN PULSING SINCE THE AFTERNOON HOURS IN THOSE
AREAS .OVERNIGHT...A MID LEVEL SHORT WAVE MOVING INTO WEST
GEORGIA IS FORECAST TO REACH THE I-95 CORRIDOR AROUND 12Z. MODELS
INDICATE THAT PWATS WILL INCREASE OVERNIGHT WITH GRADUALLY
IMPROVING MID LEVEL INSTABILITY FROM THE SW AND W.
SHOWERS MAY BEGIN TO NUDGE INTO THE SW GEORGIA ZONES THE NEXT 1-2
HOURS BUT THIS ACTIVITY WILL PROBABLY JUST CONTINUE TO WEAKEN
PROVIDING SOME SPOTTY SHOWERS AT TIMES PRIOR TO 2 AM. AS THE SHORT
WAVE NEARS LATE...WE MAY SEE AN INCREASE IN SHOWERS ALONG THE
SAVANNAH RIVER CORRIDOR...SPREADING NE OVER PARTS OF SE SOUTH
CAROLINA AFTER 08Z-09Z. AT THIS TIME WE HAVE MAINTAINED SLIGHT
CHANCE POPS IN THE FORECAST. CANNOT RULE OUT AN ISOLATED LATE
NIGHT TSTM GIVEN A BIT OF LOW LEVEL CAPE FORECAST TO ADVECT IN OFF
THE ATLC. GIVEN UNCERTAINTIES OF OCCURRENCE...TIMING AND OVERALL
COVERAGE...WE OPTED TO HOLD OFF THUNDER MENTION IN THE FORECAST AT
THIS TIME. CONDITIONS DO NOT LOOK OVERLY FAVORABLE FOR A LOT OF
FOG BUT SINCE QUITE A BIT OF STRATUS IS MAY OCCUR LATE...WE COULD
SEE SOME VSBYS IMPACTED BY THE LOWER CIGS ADJACENT TO THE CSRA
AND SOUTHERN MIDLANDS.
ABUNDANT HIGHER LEVEL CLOUDS AND THE FORMATION OF STRATUS/STRATOCU
WILL MAKE FOR MOSTLY CLOUDY OVERNIGHT. THAT ALONG WITH WEAK WARM
ADVECTION WILL LIMIT LOWS TO AN WARM 66-70F...OR ABOUT 8-9F ABOVE
NORMAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
AN UNSETTLED PATTERN EXPECTED THROUGH THIS PERIOD. A BROAD...
POSITIVELY TILTED UPPER LEVEL TROUGH...WILL REMAIN OVER THE NORTH-
CENTRAL PORTION OF THE COUNTRY. THIS WILL KEEP OUR REGION ON THE
SOUTHEAST PERIPHERY OF THE UPPER TROUGH...WITH PERIODIC WEAK UPPER
IMPULSES EXPECTED TO MOVE ACROSS THE REGION SUNDAY AND MONDAY. GIVEN
THE WEAKNESS OF THE UPPER FEATURES...TIMING OF CONVECTION IS
CHALLENGING. FOR SUNDAY AND MONDAY...HAVE KEPT CHANCE POPS FOR MUCH
OF THE AREA. GIVEN UPPER FORCING IS WEAK THROUGH THIS PERIOD...FEEL
BEST CHANCES WILL BE DURING THE AFTERNOON COINCIDENT WITH MAXIMUM
HEATING. CAPE VALUES ARE MODERATE IN THE 1000-1500 J/KG RANGE...BUT
WEAK BULK SHEARS WILL MEAN ANY THUNDERSTORM ACTIVITY SHOULD REMAIN
BELOW SEVERE LIMITS AND LACK ORGANIZATION. ALTHOUGH GUIDANCE
MAINTAINS HIGHER POPS THAN TYPICAL DURING THE NIGH TIME
PERIODS...CONFIDENCE NOT VERY HIGH THAT THIS WILL OCCUR. NEVER THE
LESS...HAVE KEPT LOW END CHANCE DURING THE NIGHT TO REMAIN CLOSER TO
GUIDANCE AND COLLABORATE BETTER WITH SURROUNDING OFFICES.
TUESDAY WILL HAVE THE STRONGEST/BEST UPPER LEVEL SUPPORT AS THE
BROAD TROUGH SHARPENS AND MOVES E-NE TOWARD THE MID ATLANTIC. AT THE
SURFACE...A WEAK LOW PRESSURE SYSTEM IS PROGGED TO TRACK ACROSS
THE CAROLINAS AND MID ATLANTIC. THIS WILL KEEP THE AREA ON THE
WARM/UNSTABLE SIDE OF THE SYNOPTIC LOW. HAVE KEPT HIGH END CHANCE
POPS...BUT WOULD NOT BE SURPRISED IF LATER FORECASTS NUDGE INTO
LIKELY OR HIGHER POPS. GIVEN BETTER UPPER FORCING FROM THE
TROUGH...AS WELL AS BEING ON THE ENTRANCE SIDE OF AN UPPER
JET...WILL BE MONITORING THE POTENTIAL FOR SOME STORMS TO BE
STRONG OR POSSIBLY SEVERE. TOO SOON TO ADD MENTION DUE TO
UNCERTAINTY WITH TIMING OF THE UPPER FEATURES AND DEEP LAYER
MOISTURE...WHICH MAY BE DEPARTING THE AREA BY LATE MORNING/EARLY
AFTERNOON. IF THAT HAPPENS...CHANCES FOR ANY STRONG STORMS WILL BE
MUCH LOWER. HIGHS IN THE LOWER 80S AND LOWS IN THE MID TO UPPER
60S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THERE IS STILL A FAIR AMOUNT OF DISAGREEMENT WITH THE MODELS TUESDAY
NIGHT ONWARD. THE 00Z GFS HAS WEAK LOW PRESSURE HOVERING OVER OR
NEAR US TUESDAY NIGHT INTO WEDNESDAY...THEN MOVING TO THE NORTHEAST
WEDNESDAY NIGHT FOLLOWED BY BUILDING HIGH PRESSURE THURSDAY. THE 00Z
ECMWF HAS A MUCH STRONGER/STRENGTHENING LOW DURING THIS SAME TIMER
PERIOD. HOWEVER...WRAP AROUND SHOWERS WILL PERSIST INTO THURSDAY
BEFORE HIGH PRESSURE BUILDS THURSDAY NIGHT INTO FRIDAY. THE 00Z
CANADIAN SEEMS TO BE IN THE MIDDLE OF THESE TWO...EXCEPT IT BRINGS
THE HIGH PRESSURE IN WEDNESDAY NIGHT. GIVEN ALL THE DIFFERENT
SOLUTIONS AND A GENERAL TROUGH OVER THE EAST COAST...OPTED TO KEEP
CHANCE POPS TUESDAY NIGHT INTO WEDNESDAY...FOLLOWED BY POPS TRENDING
DOWNWARD TO SLIGHT CHANCE WEDNESDAY NIGHT INTO THURSDAY. BUILDING
HIGH PRESSURE WILL BRING DRY CONDITIONS ON FRIDAY WITH BELOW NORMAL
TEMPERATURES.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
VFR INTO EARLY TONIGHT. CONDITIONS SHOULD DETERIORATE TO MVFR OR
PERHAPS IFR AT BOTH TERMINALS OVERNIGHT INTO SUNDAY MORNING...AS
BOUNDARY LAYER MOISTURE INCREASES WITHIN A SE/SOUTH FLOW. 18Z NAM
SOUNDINGS INDICATE A WEAKER NOCTURNAL INVERSION AND THIS COULD
MEAN A TRICKY FORECAST FOR THE OVERNIGHT WITH RESPECT TO CLOUD
COVERAGE AND TIMING CIGS IN THE COASTAL CORRIDOR. WHILE THERE
COULD BE A SHRA LATE TONIGHT INTO EARLY SUNDAY AT BOTH TERMINALS
DUE TO ENERGY MOVING IN ALOFT...ANY IMPACTS WOULD BE FAIRLY
BENIGN. VFR CONDITIONS WILL RETURN THE SECOND HALF OF SUNDAY
MORNING INTO EARLY AFTERNOON. DIURNAL CONVECTION POTENTIAL LOOKS
TOO LOW ON SUNDAY FOR ANY EARLY MENTIONS.
EXTENDED AVIATION OUTLOOK...UNSETTLED CONDITIONS WILL RESULT IN
THE CHANCE FOR PERIODIC FLIGHT RESTRICTIONS WITHIN SCATTERED
SHOWERS/THUNDERSTORMS...MAINLY DURING THE AFTERNOON HOURS BOTH
KCHS AND KSAV THROUGH TUESDAY.
WEDNESDAY AND THURSDAY...LATEST MEDIUM RANGE GUIDANCE INDICATING
THE AREA WILL BE AT THE SOUTHERN END/BASE OF A LARGE...CLOSED UPPER
LOW OVER THE NE U.S./SE CANADA. WITH MUCH DRIER DEEP
LAYER MOISTURE...EXPECT THAT VFR WILL DOMINATE THIS PERIOD.
&&
.MARINE...
OVERNIGHT...A DECAYING STATIONARY FRONT NEAR THE NC/SC BORDER AND
EXTENDING EAST/SE INTO THE ATLANTIC AS A 1025 MB HUGGING THE COAST
OF NEW ENGLAND CONTINUES TO POKE SW ACROSS THE LOCAL WATERS. THIS
SUPPORTS A MODEST EAST/SE FLOW WITH SPEEDS 10-15 KT AND SEAS
BUILDING TO 2-4 FT...HIGHEST BEYOND 40 NM OFF THE GA COAST.
SUNDAY THROUGH THURSDAY...NO HIGHLIGHTS ARE EXPECTED THROUGH THE
PERIOD. IN GENERAL...THE WATERS WILL SIT BETWEEN ATLANTIC HIGH
PRESSURE WELL ENE OF THE AREA AND LOWER PRESSURE OVER THE MID
ATLANTIC AND CAROLINAS. THIS WILL RESULT IN SOUTH-SOUTHWEST WINDS
OF 15 KNOTS OR LESS AND SEAS 3 FEET OR LESS. UNSETTLE CONDITIONS
LIKELY WITH SCATTERED SHOWER AND THUNDERSTORMS...ESPECIALLY MONDAY
AND TUESDAY.
&&
.EQUIPMENT...
THE CHARLESTON HARBOR NOS TIDE GAUGE HAS STOPPED REPORTING ALL
METEOROLOGICAL AND TIDE DATA. THE NATIONAL OCEAN SERVICE IS
INVESTIGATING THE CAUSE OF THE OUTAGE. AN ESTIMATED TIME FOR DATA
RESTORATION IS UNKNOWN AT THIS TIME.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
EQUIPMENT...
Area Forecast Discussion
National Weather Service Lincoln IL
900 PM CDT SAT APR 30 2016
.UPDATE...
Issued at 900 PM CDT Sat Apr 30 2016
Surface low this evening is located just northwest of St. Louis
and expected to move slowly east or ESE overnight...arriving near
Lawrenceville by dawn. An instability axis around 1000 J/KG CAPE
extending from near th low center southward resulted in several
severe thunderstorms from near the Quincy area through the St.
Louis area with over 1 inch hail. Nevertheless, these storms have
remained just outside the central IL forecast area and will
continue to skirt the edges of this forecast area from Near the
Jacksonville area to Shelbyville to Effingham and southward. A
line of thunderstorms east of the St. Louis metro area currently
looks to arrive in Effingham and Clay Counties around 10 p.m.
however nocturnal stabilization may trend these storms sub-severe
by that point. Updates this evening have been for short term radar
trends on thunderstorm coverage. Otherwise, forecast looks in good
shape with lows ranging from the upper 40s in Galesburg and Peoria
to the Upper 50s south of I-70. Showers and thunderstorms will
decrease late in the night with the low shifting
eastward...although showers may arrive by early morning northwest
of the Illinois River.
&&
.SHORT TERM...(Tonight)
ISSUED AT 255 PM CDT Sat Apr 30 2016
19z/2pm surface analysis shows 1004mb low over northern Missouri,
with warm front extending E/SE into southern Illinois. After being
nearly stationary for much of the day, the front is slowly lifting
northward and should eventually stall between the I-72 and I-70
corridors this evening. Most of the steady rain from earlier has
pushed into northern Illinois, leaving behind only isolated showers
across the KILX CWA this afternoon. Will be watching locations near
and south of the warm front where latest LAPS data is showing
SBCAPES of 1000-1500J/kg across Missouri into the Ozarks. Visible
satellite imagery is beginning to show the first signs of convective
development from just west of St. Louis southward into Arkansas.
HRRR suggests scattered thunderstorms will develop within this
corridor over the next couple of hours, then will spread E/NE into
portions of central Illinois tonight. Based on expected position of
front and latest HRRR forecast, think the best storm chances will
remain across the southern half of the CWA through the evening
hours, with any convection pushing further east into Indiana by
midnight. With surface low pressure tracking into the area and
winds becoming light/variable, think fog will become an issue later
tonight within the very moist low-level airmass. While MET/MAV
guidance only show minor reductions in visby, the HRRR is much more
bullish with the fog, particularly near the expected position of the
front. Have therefore included areas of fog in the forecast for all
locations north of I-70, with patchy fog further south into the warm
sector.
.LONG TERM...(Sunday through Saturday)
ISSUED AT 255 PM CDT Sat Apr 30 2016
Morning upper air and satellite imagery showed spinning upper closed
low over northeast CO-southwest NE. Models in good agreement on
drifting it to the east overnight, which should provide upper
support for instability showers over region on Sunday. For
overnight, best instability in area of MO where CAPE values have
increased due to cloud break up this afternoon. Expect storm
development still possible in along and south of warm frontal zone,
then pcpn moving north into central IL region. Pcpn should remain
elevated, as cold dome north of front has been reinforced by
rainfall today, so only marginal risk of severe, with mainly hail
threat in a few stronger storms.
Upper system drifts through on Sunday, with scattered showers
triggered. Pcpn break Sunday night, then a second upper wave moves
through that will trigger slight chance of showers over parts of
area.
Upper flow becomes northwesterly into midweek, with a minor wave
moving through Tuesday night into Wednesday. Instability showers
again possible with cool air aloft with this wave. Temperatures
through next week with be generally cool and below normal.
Surface low expected to track northeast across the region this
evening, reaching northeast Indiana by midnight, although the GFS is
quite a bit slower with this scenario. General thought is that the
steadier showers will be quickly diminishing this evening, with a
good portion of the overnight hours dry. However, the remnants of
the upper low currently along the Colorado/Kansas border will move
across southern Iowa Sunday morning and across Illinois in the
afternoon, bringing another period of scattered showers to the area
by midday. Have included isolated thunder mention in the afternoon
most areas, as the trough moves overhead. Any lingering showers
should be out of the area around sunset.
Highly amplified pattern expected next week, as upper level ridging
over the western U.S. builds well into British Columbia and Alberta.
Longer range models showing some differences with the extent of the
corresponding upper trough over the eastern half of the CONUS, with
the ECMWF on the deeper side. This would trend toward significantly
cooler conditions over the Midwest during the second half of the
work week. By the end of the week, the upper pattern on both the GFS
and ECMWF models trends toward an omega block type configuration
which would linger the cooler air even longer. Have trended downward
on the temperatures for late in the week, although not as low as the
blended raw model guidance at this point.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 643 PM CDT Sat Apr 30 2016
Low pressure centered near KUIN in west-central IL will continue
moving ESE overnight reaching around KLWV by 12Z. South of the low
track considerable clearing taking place with VFR ceilings and
numerous breaks in cloud cover. This area will also see scattered
thunderstorm development through the evening. North of the
low...IFR ceilings and visibilities with local LIFR ceilings noted
in the current observations. Overnight lower ceilings will spread
back southward behind the low track. In addition...copious
moisture and light winds will allow for decreasing visibilities in
fog to develop as well. Therefore have decreased conditions to IFR
or LIFR across the forecast area overnight...steadily improving
after 16Z with daytime heating. Although showers and thunderstorms
will taper off overnight...an upper level disturbance Sunday
afternoon will bring a return of scattered showers and isolated
thunderstorms to the area.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Onton
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Onton
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
751 PM CDT SAT APR 30 2016
.UPDATE...
746 PM CDT
STEADIER RAIN CONTINUES TO LIFT NORTH OF THE CWA THIS
EVENING...WITH ADDITIONAL SHOWERY DEVELOPMENT OR DRIZZLE STILL
LINGERING OVER MUCH OF THE CWA. WHILE LARGE SCALE ASCENT WILL
REMAIN PRESENT THIS EVENING/OVERNIGHT WITH THE UPPER LEVEL SYSTEM
JUST TO THE WEST...ISENTROPIC ASCENT WILL LIKELY AID IN EITHER
LIGHT RAIN OR DRIZZLE FOR MUCH OF THE CWA. SO HAVE MAINTAINED
CAT/LIKELY POPS THIS EVENING AND THEN LOWER TO CHANCE WORDING
AFTER MIDNIGHT. HAVE MADE LITTLE CHANGES TO LOW TEMPS
TONIGHT...WITH TEMPS EITHER HOLDING NEARLY STEADY OR SHOWING A
SLIGHT WARMING TREND.
RODRIGUEZ
&&
.SHORT TERM...
146 PM CDT
THROUGH SUNDAY...
COOL/CLOUDY/MOIST AIRMASS CONTINUES TO LIFT NORTH ACROSS NORTHERN
IL/NORTHWEST IN THIS AFTERNOON. IR IMAGERY HAD INITIALLY INDICATED
CLOUD TOPS WERE BETWEEN -60 TO -65 DEG C...BUT OVER THE PAST FEW
HOURS CLOUDS HAVE BEEN QUICKLY WARMING WITH TOPS NOW BETWEEN -50
TO -55 DEG C. IN ADDITION A WEDGE OF DRIER AIR CONTINUES TO LIFT
NORTHEAST AS THE AREA OF LOW PRESSURE MOVES INTO SOUTHCENTRAL IOWA
THIS AFTERNOON. THE PRESSURE GRADIENT HAS ARRIVED OVER NORTHERN IL
THIS AFTERNOON WITH EASTERLY WINDS INCREASING TO BETWEEN 10-15KT
AND GUSTS AROUND 20KT. THE LOW WILL BEGIN TO WEAKEN THIS
EVENING...BUT WITH A BROAD RIDGE POSITIONED OVER ONTARIO IT IS
LIKELY THAT THE LOW WILL STALL FROM LIFTING NORTHEAST OVERNIGHT.
THIS WILL SET THE STAGE FOR STEADIER PRECIP TO SHIFT NORTH AND
END LATE THIS AFTERNOON FROM SOUTH TO NORTH...WITH JUST A FEW
LINGERING SHOWERS THROUGH THE OVERNIGHT. THE BAGGY ATMOSPHERE
WILL CONTINUE TO SEE SHALLOW MOISTURE FEED ACROSS THE
REGION...WITH CONSIDERABLY LOWER CEILINGS OVERNIGHT. THE LACK OF A
LIFT WILL KEEP DROPLET SIZE MINIMAL AND LIKELY LEAD TO PATCHY
DRIZZLE/LGT RAIN. TEMPS OVERNIGHT WILL LIKELY NOT CHANGE
MUCH...WITH LOWS IN THE 40S.
WITH THE BROAD SFC RIDGE DISPLACED TO THE NORTH...THIS WILL KEEP
THE WARM FRONTAL BOUNDARY FROM LIFTING TOO FAR NORTH TOWARDS THE
CWFA OVERNIGHT INTO SUNDAY...HOWEVER THE 500MB VORT MAX WILL BE
UPSTREAM ACROSS SOUTHWEST IOWA TO STAR THE DAY SUNDAY. AS THIS
FEATURE PIVOTS NORTHEAST ACROSS NORTHERN IL...FORCING WILL RETURN
WITH INCREASED CHANCES FOR SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORM SOUTH OF I-80 SUNDAY AFTERNOON. THE NORTHEAST FLOW
OFF OF LAKE MICHIGAN WILL LIKELY KEEP TEMPS AGAIN SUN AFTN IN THE
40S FOR AREAS ADJACENT TO THE LAKE...MEANWHILE FURTHER INLAND
TEMPS SHOULD BE ABLE TO WARM INTO THE LOW/MID 50S. ACROSS THE
SOUTHERN CWFA THE WARM FRONTAL BOUNDARY WILL BE LINGERING NEARBY
WITH TEMPS NEARING THE LOW 60S.
BEACHLER
&&
.LONG TERM...
243 PM CDT
SUNDAY NIGHT THROUGH SATURDAY...
MAIN CONCERN GOING INTO THE LONGER TERM FORECAST PERIOD WILL BE THE
TEMPERATURE TREND THROUGH THE PERIOD. BY SUNDAY NIGHT...ANY
LINGERING PCPN ASSOCIATED WITH THE SYSTEM CURRENTLY BRINGING RAIN TO
NRN IL/NWRN IN WILL COME TO AN END FROM WEST TO EAST AS THE MAIN
SHORTWAVE SHIFTS TO THE ERN GREAT LAKES. A SERIES OF WEAK
SHORTWAVES IS EXPECTED TO DROP OUT OF THE NRN PLAINS AND ACROSS THE
UPPER MIDWEST EARLY NEXT WEAK...BUT AS HIGH PRESSURE BUILDS FROM THE
CENTRAL PLAINS THROUGH THE GREAT LAKES...AN EXTENDED PERIOD OF
GENERALLY NELY FLOW WILL KEEP MOISTURE ACROSS THE REGION VERY
LIMITED AND BY THE TIME A WEAK ASSOCIATED SFC FRONT MOVES THROUGH
THE AREA...ANY CHANCES FOR PCPN WILL BE MINIMAL AND...FOR NOW...WILL
ONLY CARRY SOME SLIGHT CHANCE POPS FOR THE FAR SERN PORTIONS OF THE
CWA ON MONDAY. ALSO BY EARLY NEXT WEEK...THE UPPER LEVEL PATTERN IS
EXPECTED TO UNDERGO SIGNIFICANT AMPLIFICATION...WITH STRONG RIDGING
BUILDING OVER THE WRN CONUS AND DEEP LONG WAVE TROUGHING DEVELOPING
OVER THE ERN CONUS. WHILE THE LONGER RANGE GUIDANCE IS RELATIVELY
CONSISTENT ON THE GENERAL SCENARIO...THERE ARE SIGNIFICANT ENOUGH
DIFFERENCES IN THE FINER SCALE DETAILS...IN PARTICULAR THE SPEED OF
PROGRESSION OF THE LONG WAVE PATTERN. CONSEQUENTLY...THE TRACK OF
SHORT WAVE ENERGY DROPPING SEWD DOWN THE ERN PERIPHERY OF THE UPPER
RIDGE IS DIFFERENT ENOUGH THAT THE DEGREE OF CONFIDENCE IN THE
LONGER TERM FORECAST RAPIDLY DETERIORATES WITH TIME FROM TUESDAY
THROUGH THE END OF THE WEEK. SO...IN GENERAL...EXPECT A PERIOD OF
CHANGEABLE WEATHER FOR THE MIDDLE AND LATTER PORTIONS OF NEXT
WEAK...ESPECIALLY TEMPERATURES. WHILE THERE SHOULD BE PERIODS OF
SEASONABLE AND BELOW NORMAL TEMPERATURES THROUGH THE WEEK...
CONFIDENCE IN THE TIMING IS LOW.
KREIN
&&
.AVIATION...
FOR THE 00Z TAFS...
CONCERNS FOR THE 0Z TAF CYCLE INCLUDE
-VERY LOW CEILINGS AND TIMING LOWERING/RISING TIMES
-IFR VISIBILITY AT TIMES...ESPECIALLY TONIGHT INTO EARLY SUNDAY
-TIMING OF THE END OF DRIZZLE AND RETURN OF SHOWERS ON SUNDAY
THE BACK EDGE OF THE MAIN RAIN SHIELD WILL CROSS THE TERMINALS
AROUND OR EVEN BEFORE THE 0Z HOUR...BUT VERY LIGHT RAIN/DRIZZLE
WILL CONTINUE THIS EVENING. IN SPITE OF THE CLEARING SEEN ON
VISIBLE SATELLITE...NE ILLINOIS AND NW INDIANA WILL LARGELY REMAIN
ON THE COOL SIDE OF A LOW LEVEL WARM FRONT. THERE CONTINUED WEAKER
LIFT OVER THIS BOUNDARY INTO A MOIST LOW LEVEL ENVIRONMENT WILL
MAINTAIN LIGHT RAIN/DRIZZLE AT LEAST INTO THE EARLY MORNING HOURS.
THIS PATTERN WILL ALSO TEND TO ALLOW THE LOW CLOUDS TO PERSIST AND
POSSIBLY EVEN LOWER SOME OVERNIGHT. THE DRIZZLE SEEMS FAVORED TO
END BEFORE DAYBREAK ON SUNDAY...WHICH MAY HELP VISIBILITY VALUES
TO START SUNDAY...BUT LOW CIGS LOOK TO CONTINUE. GUIDANCE
CONTINUES TO SUGGEST LIFR TO DOMINATE TONIGHT INTO SUNDAY...WITH
VERY SLOW IMPROVEMENT EXPECTED INTO THE AFTERNOON AS IFR THEN
POSSIBLY MVFR CONDITIONS LATE IN THE DAY...THOUGH WHETHER THIS
IMPROVEMENT OCCURS AND THE TIMING OF THE TRANSITION IS OF LOW
CONFIDENCE. MOST GUIDANCE HOLDS AT 300 FT MOST OF THE NIGHT...AND
TRIED TO SHOW SOME IMPROVEMENT ABOVE THIS THRESHOLD THROUGH THE
MORNING...BUT AGAIN TIMING CONFIDENCE IS LOW.
THERE COULD BE SOME LIGHTER PRECIP AROUND IN THE MORNING...BUT THE
BETTER CHANCE FOR ORGANIZED RA/SHRA RETURNS SUNDAY
AFTERNOON/EVENING AS THE UPPER LEVEL LOW CENTER ROTATES THROUGH.
AT THIS POINT ANY LIMITED THUNDER THREAT LOOKS TO REMAIN
SOUTH/EAST OF THE TERMINALS.
KMD
&&
.MARINE...
255 PM CDT
A LARGE AREA OF HIGH PRESSURE CENTERED OVER CENTRAL CANADA WILL
SLOWLY MOVE TO THE EAST OVER THE NEXT COUPLE DAYS WHILE LOW
PRESSURE OVER THE UPPER MISSOURI VALLEY TRACKS TO THE EAST ACROSS
CENTRAL IL/IN LATE TONIGHT AND TOMORROW. THIS WILL KEEP PERSISTENT
ELY-NELY FLOW OVER THE LAKE. WINDS AND WAVES HAZARDOUS TO SMALL
CRAFT SHOULD CONTINUE OVER THE IL NEARSHORE WATERS THROUGH SUNDAY
NIGHT AS A MODERATE ELY-NELY PRESSURE GRADIENT REMAINS IN PLACE.
HIGH PRESSURE WILL THEN SETTLE ACROSS THE NORTHERN AND CENTRAL
GREAT LAKES REGION ON MONDAY...SETTING UP A PERIOD OF RELATIVELY
QUIET CONDITIONS OVER LAKE MICHIGAN. THE HIGH PRESSURE RIDGE WILL
WEAKEN ON TUESDAY WHILE PUSHING SOUTH INTO THE OHIO VALLEY AND
DEEPENING LOW PRESSURE MOVES SOUTHEAST ACROSS ONTARIO INTO
THE UPPER GREAT LAKES TUESDAY NIGHT WITH A TRAILING COLD FRONT
PUSHING SOUTH ACROSS THE WESTERN LAKES. ANOTHER AREA OF HIGH
PRESSURE BUILDING OVER THE CANADIAN PRAIRIES BY MIDWEEK AS THE LOW
MOVES OFF TO THE EAST SHOULD BRING STRENGTHENING NWLY-NLY FLOW TO
THE LAKE FOR THE MIDDLE AND LATTER PORTIONS OF NEXT WEEK. AT THIS
POINT...EXPECT WINDS TO REMAIN BELOW GALE FORCE...BUT IF THE COLD
ADVECTION AND PRESSURE RISES BEHIND THE EXITING COLD FRONT ARE
STRONG ENOUGH...THE POTENTIAL FOR GALES CANNOT BE RULED OUT BY THE
END OF THE WEEK.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 AM
MONDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
643 PM CDT SAT APR 30 2016
.SHORT TERM...(Tonight)
ISSUED AT 255 PM CDT Sat Apr 30 2016
19z/2pm surface analysis shows 1004mb low over northern Missouri,
with warm front extending E/SE into southern Illinois. After being
nearly stationary for much of the day, the front is slowly lifting
northward and should eventually stall between the I-72 and I-70
corridors this evening. Most of the steady rain from earlier has
pushed into northern Illinois, leaving behind only isolated showers
across the KILX CWA this afternoon. Will be watching locations near
and south of the warm front where latest LAPS data is showing
SBCAPES of 1000-1500J/kg across Missouri into the Ozarks. Visible
satellite imagery is beginning to show the first signs of convective
development from just west of St. Louis southward into Arkansas.
HRRR suggests scattered thunderstorms will develop within this
corridor over the next couple of hours, then will spread E/NE into
portions of central Illinois tonight. Based on expected position of
front and latest HRRR forecast, think the best storm chances will
remain across the southern half of the CWA through the evening
hours, with any convection pushing further east into Indiana by
midnight. With surface low pressure tracking into the area and
winds becoming light/variable, think fog will become an issue later
tonight within the very moist low-level airmass. While MET/MAV
guidance only show minor reductions in visby, the HRRR is much more
bullish with the fog, particularly near the expected position of the
front. Have therefore included areas of fog in the forecast for all
locations north of I-70, with patchy fog further south into the warm
sector.
.LONG TERM...(Sunday through Saturday)
ISSUED AT 255 PM CDT Sat Apr 30 2016
Morning upper air and satellite imagery showed spinning upper closed
low over northeast CO-southwest NE. Models in good agreement on
drifting it to the east overnight, which should provide upper
support for instability showers over region on Sunday. For
overnight, best instability in area of MO where CAPE values have
increased due to cloud break up this afternoon. Expect storm
development still possible in along and south of warm frontal zone,
then pcpn moving north into central IL region. Pcpn should remain
elevated, as cold dome north of front has been reinforced by
rainfall today, so only marginal risk of severe, with mainly hail
threat in a few stronger storms.
Upper system drifts through on Sunday, with scattered showers
triggered. Pcpn break Sunday night, then a second upper wave moves
through that will trigger slight chance of showers over parts of
area.
Upper flow becomes northwesterly into midweek, with a minor wave
moving through Tuesday night into Wednesday. Instability showers
again possible with cool air aloft with this wave. Temperatures
through next week with be generally cool and below normal.
Surface low expected to track northeast across the region this
evening, reaching northeast Indiana by midnight, although the GFS is
quite a bit slower with this scenario. General thought is that the
steadier showers will be quickly diminishing this evening, with a
good portion of the overnight hours dry. However, the remnants of
the upper low currently along the Colorado/Kansas border will move
across southern Iowa Sunday morning and across Illinois in the
afternoon, bringing another period of scattered showers to the area
by midday. Have included isolated thunder mention in the afternoon
most areas, as the trough moves overhead. Any lingering showers
should be out of the area around sunset.
Highly amplified pattern expected next week, as upper level ridging
over the western U.S. builds well into British Columbia and Alberta.
Longer range models showing some differences with the extent of the
corresponding upper trough over the eastern half of the CONUS, with
the ECMWF on the deeper side. This would trend toward significantly
cooler conditions over the Midwest during the second half of the
work week. By the end of the week, the upper pattern on both the GFS
and ECMWF models trends toward an omega block type configuration
which would linger the cooler air even longer. Have trended downward
on the temperatures for late in the week, although not as low as the
blended raw model guidance at this point.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 643 PM CDT Sat Apr 30 2016
Low pressure centered near KUIN in west-central IL will continue
moving ESE overnight reaching around KLWV by 12Z. South of the low
track considerable clearing taking place with VFR ceilings and
numerous breaks in cloud cover. This area will also see scattered
thunderstorm development through the evening. North of the
low...IFR ceilings and visibilities with local LIFR ceilings noted
in the current observations. Overnight lower ceilings will spread
back southward behind the low track. In addition...copious
moisture and light winds will allow for decreasing visibilities in
fog to develop as well. Therefore have decreased conditions to IFR
or LIFR across the forecast area overnight...steadily improving
after 16Z with daytime heating. Although showers and thunderstorms
will taper off overnight...an upper level disturbance Sunday
afternoon will bring a return of scattered showers and isolated
thunderstorms to the area.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Onton
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
100 PM CDT FRI APR 29 2016
.SHORT TERM...
254 AM CDT
TODAY THROUGH TONIGHT...
WEAKENING CLOSED LOW OVER SOUTHERN WI/LAKE MICHIGAN WILL SHEAR
EASTWARD ACROSS THE GREAT LAKES REGION THIS MORNING...ALONG WITH
ASSOCIATED WEAK SURFACE LOW. SUBSIDENCE IN THE WAKE OF THIS
FEATURE IS INDICATED BY RISING HEIGHTS AND DRYING/WARMING OF THE
COLUMN FROM MID-MORNING INTO THIS EVENING. THIS SHOULD BRING AN
END TO ANY LINGERING LIGHT RAIN/DRIZZLE EARLY IN THE DAY. LIGHT
ANTICYCLONIC SFC WINDS WILL MAINTAIN COOL NORTHEAST FLOW...THROUGH
FORECAST SOUNDINGS DO INDICATE THAT SOME THINNING/EROSION OF LOW
CLOUDS IS POSSIBLE LATE IN THE DAY. ANY BRIEF PEAKS OF SUN WILL
NOT DO MUCH TO BOOST TEMPS HOWEVER. LOW LEVEL THERMAL FIELDS IN
GOOD AGREEMENT WITH GUIDANCE NUMBERS FOR AFTERNOON HIGHS...RANGING
FROM THE 40S AT THE LAKE SHORE TO THE MID/UPPER 50S ACROSS NORTH
CENTRAL IL...AND LOW/MID 60S FAR SOUTH COUNTIES.
WFO LOT FORECAST AREA BRIEFLY FINDS ITSELF BENEATH SHORT WAVE
RIDGE AXIS TONIGHT...ALTHOUGH INFLUENCE OF THE NEXT UPPER LOW
EMERGING FROM THE CENTRAL/SOUTHERN ROCKIES BEGINS OVERNIGHT
PRIMARILY IN THE FORM OF STRENGTHENING COOL EASTERLY WINDS ACROSS
THE CWA AND REDEVELOPMENT AND THICKENING OF CLOUD COVER AS THE
STATIONARY FRONTAL BOUNDARY CURRENTLY OVER THE SOUTHERN PLAINS AND
LOWER MISSISSIPPI VALLEY DEVELOPS NORTHWARD AS A WARM FRONT. SOME
OF THE AVAILABLE GUIDANCE SPREADS PRECIP INTO THE FAR SOUTHERN
COUNTIES OF THE CWA PRIOR TO SATURDAY MORNING...AND WHILE THE 00Z
WRF/21Z SREF MIGHT BE A BIT TOO FAR NORTH GIVEN THE SPREAD IN
MODEL OUTPUT...AT LEAST SOME LOW CHANCE POPS REMAIN APPROPRIATE
ACROSS THE SOUTH AFTER MIDNIGHT TONIGHT.
RATZER
&&
.LONG TERM...
254 AM CDT
SATURDAY THROUGH THURSDAY...
MAIN FORECAST FOCUS IS ON CONTINUATION OF COOL/WET WEATHER
THROUGH THE WEEKEND...AS PLAINS UPPER EVENTUALLY IS ABSORBED BY
EASTERN NORTH AMERICAN UPPER TROUGH.
UPPER LOW IS PROGGED TO BE OVER THE CENTRAL HIGH PLAINS SATURDAY
MORNING WITH SURFACE LOW PRESSURE OVER EASTERN KANSAS. MID-LEVEL
SHORT WAVE ENERGY IS DEPICTED ROTATING NORTHEASTWARD AROUND THE
UPPER LOW AND INTO THE REGION DURING THE DAY...AS 30-40 KT 850 MB
WINDS WORK TO LIFT THE ELEVATED WARM FRONTAL ZONE ACROSS CENTRAL
AND NORTHERN IL/IN. PERIOD OF INCREASED MOISTURE
CONVERGENCE/MOISTURE FLUX ON THE NOSE OF 1+ INCH PWAT AXIS
SUPPORTS HIGHEST POPS DURING THE DAY SATURDAY. PLUME OF 7-7.5 C/KM
700-500 MB LAPSE RATES AND WEAK COUPLED JET STRUCTURE ALOFT ALSO
POINT TO EMBEDDED ELEVATED THUNDER POTENTIAL ESPECIALLY ACROSS THE
SOUTHERN HALF OF THE CWA. GUIDANCE VARIES A BIT WITH PLACEMENT AND
AMOUNTS...THOUGH A GENERAL 0.90-1.25 INCH QPF AXIS IS NOTED ACROSS
THE CENTRAL/SOUTHERN PARTS OF THE CWA BY MIDNIGHT SATURDAY NIGHT.
PRECIP THREAT CONTINUES SATURDAY NIGHT AND INTO SUNDAY AS UPPER
LOW CIRCULATION SHEARS EASTWARD ALONG NEARLY STATIONARY ELEVATED
BAROCLINIC ZONE...THOUGH LIGHTER AMOUNTS AND COVERAGE ARE
ANTICIPATED AS OVERALL DYNAMICS WEAKEN AND DRIER AIR IS ENTRAINED
IN MID-LEVELS PER FORECAST SOUNDINGS. THE WEAKENING UPPER LOW
CIRCULATION EVENTUALLY IS ABSORBED INTO UPPER TROUGH OVER
NORTHEASTERN NORTH AMERICA SUNDAY NIGHT WITH DEEPER DRYING NOTED.
THICKER CLOUD COVER... PRECIP AND PERSISTENT EAST TO NORTHEAST LOW
LEVEL WINDS WILL KEEP TEMPERATURES BELOW NORMAL THROUGH THE
WEEKEND. LOW LEVEL THERMAL FIELDS SUPPORT GENERAL GUIDANCE TRENDS
OF HIGHS FROM THE 40S (NEAR THE LAKE) AND LOWER 50S ACROSS THE
NORTHERN CWA SATURDAY...WITH UPPER 50S IN THE SOUTH. 925-950 TEMPS
ARE ACTUALLY A LITTLE WARMER SUNDAY NORTH AND WITH POTENTIAL FOR
SOME PARTIAL CLEARING IN THE AFTERNOON HIGHS IN THE UPPER
50S/AROUND 60 APPEAR REASONABLE AWAY FROM COOL NORTHEAST FLOW OFF
THE LAKE.
FOR DAYS 4-7...MONDAY THROUGH THURSDAY...TROUGHING OVER EASTERN
NORTH AMERICA REMAINS DOMINANT THROUGH THE PERIOD WITH GENERAL
MODEL AGREEMENT IN BRINGING A RELATIVELY STRONG MID-LEVEL SHORT
WAVE AND ASSOCIATED SURFACE TROUGH ACROSS THE REGION IN NORTH-
NORTHWEST FLOW IN THE WEDNESDAY TIME FRAME. SLIGHTLY BELOW NORMAL
TEMPS LOOK TO PERSIST OUTSIDE OF TUESDAY-WEDNESDAY PERIOD WITH THE
APPROACH OF THE COLD FRONT...WITH THE TUESDAY NIGHT/WEDNESDAY
PERIOD ALSO HAVING THE BEST CHANCE FOR SOME SCATTERED SHOWERS WITH
FROPA. MAINTAINED A BLENDED GUIDANCE APPROACH WITH
TEMPS...GENERALLY LOW-MID 60S AWAY FROM LAKE MICHIGAN AND LOW-MID
50S NEAR THE LAKE WITH UPPER 60S/AROUND 70 TUESDAY-WEDNESDAY.
RATZER
&&
.AVIATION...
FOR THE 18Z TAFS...
MVFR CIGS ACROSS THE AREA WILL PERSIST INTO MID AFTERNOON BUT
THERE ARE HINTS OF SCATTERING OR AT LEAST LIFTING TOWARD HIGHER
MVFR OR VFR. WINDS FROM THE NORTHEAST QUADRANT ALSO WILL PREVAIL
THROUGH THE TAF PERIOD. THERE IS SOME UNCERTAINTY IN THE TIMING
OF PRECIP TOMORROW BUT THE MOST FAVORABLE PERIOD WOULD BE
AFTERNOON. IT ALSO IS NOT CLEAR HOW LOW CIGS/VSBYS MIGHT GO AS THE
RAIN BECOMES MORE PERSISTENT...BUT ANOTHER PERIOD OF IFR APPEARS
POSSIBLE OR LIKELY LATER IN THE DAY...TOWARD MID TO LATE
AFTERNOON.
LENNING
&&
.MARINE...
246 AM CDT
HIGH PRESSURE WILL REMAIN JUST NORTH OF LAKE MICHIGAN TODAY
ALLOWING LIGHT FLOW ONCE AGAIN AND AFTERNOON LAKE BREEZES TO
DEVELOP. LOW PRESSURE IS PROGGED TO DEEPEN OVER THE PLAINS TONIGHT
INTO SATURDAY ALLOWING NORTHEAST WINDS TO PICK BACK UP INTO THE 15
TO 25 KT RANGE BY SATURDAY EVENING...WITH 30 KT WINDS NOT OUT OF
THE REALM OF POSSIBILITY. THE STRONG NORTHEAST BREEZE WILL PERSIST
INTO SUNDAY...THEN SHOULD DIMINISH AGAIN SUNDAY NIGHT INTO MONDAY
AS THE LOW DEPARTS EAST AND HIGH PRESSURE BUILDS BACK ACROSS THE
REGION. THE RIDGE AXIS WILL MOVE EAST OF LAKE MICHIGAN MONDAY
NIGHT AS ANOTHER LOW PRESSURE SYSTEM DEVELOPS OVER HUDSON BAY
ALLOWING WINDS TO TURN SOUTH TO SOUTHWESTERLY. THE LOW WILL DRIVE
A COLD FRONT ACROSS LAKE MICHIGAN AROUND MIDWEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1244 PM CDT FRI APR 29 2016
.UPDATE...
Issued at 1038 AM CDT Fri Apr 29 2016
15z/10am surface analysis shows stationary frontal boundary
extending from West Virginia southwestward to an area of low
pressure over the Texas panhandle. Meanwhile, high pressure over
southern Canada dominates the weather across the Great
Lakes/Midwest. This high will gradually shift off to the east,
allowing the front to slowly lift northward tonight. In the
meantime, cool/dry weather will be on tap across central Illinois
for the remainder of the day. Quite a bit of low cloudiness
continues to blanket the northern two-thirds of the KILX CWA:
however, the HRRR suggests this cloud cover will scatter as the
day progresses. End result will be a partly to mostly cloudy day.
Highs will mainly be in the lower to middle 60s, but will top out
around 70 degrees south of I-70 where sunshine will be more
prevalent.
&&
.SHORT TERM...(Today)
ISSUED AT 342 AM CDT Fri Apr 29 2016
Quiet conditions are expected across central and southeast Illinois
today. We will be between weather systems, although there will be a
fair amount of cloud cover across the area. Expect light winds and
slightly cooler than normal temperatures. Daytime highs will top out
in the 60s at most locations.
.LONG TERM...(Tonight through Thursday)
ISSUED AT 342 AM CDT Fri Apr 29 2016
Deep trof over the western half of the CONUS will eject out another
low for the Midwest this weekend. Same kind of set up with a slow
moving system keeping much of the Midwest wet, and putting in excess
of an inch of rain anticipated for Central Illinois. A slower trend
in the models as the precip spreads from southwest to northeast
overnight tonight...mainly after midnight. The region sets up for
mainly a warm sector event from the developing low to the west.
Southerly flow of warm moisture feeding into the ongoing
precipitation for Saturday and Saturday night. Precip slowly
decreasing through Sunday night as the upper low finally progresses
through the region. Sunday night will have some clearing of the
precip with drier air wrapping around the system.
Models have had several problems...the 00z runs for the last three
nights have been different. Models are still not in agreement with
handling the pattern shift with the shearing out of the energy
remaining in the trof in the southwest. It seems an attempt at more
northwesterly flow ...but so far, the lack of gradient aloft is weak
at best, with no consistency for the energy trying to dig out a trof
over the Great Lakes. Remaining forecast is dry for now...with some
slight chances creeping in mid/end week. Temperatures are moderate
and holding near seasonal. Confidence in forecast for next week
remains weak and highly conditional.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1244 PM CDT Fri Apr 29 2016
MVFR ceilings persist at the central Illinois terminals early this
afternoon: however the HRRR continues to suggest these will
scatter over the next 2-3 hours. Have noted a gradual thinning of
the low clouds on visible satellite, so will follow the HRRR and
scatter the ceilings between 21z and 22z. A high overcast from
convective blowoff upstream will remain through the late
afternoon and evening, before clouds once again begin lowering
tonight as a warm front lifts northward into the area. Models
still disagree as to how quickly the lower clouds and precip will
return, with the NAM being the fastest. Based on a continued dry
E/NE low-level flow north of the front, think the slower GFS/Rapid
Refresh is the way to go. As such, have delayed IFR ceilings and
predominant rain until 09z at KSPI and 12z at the I-74 terminals.
Modest elevated instability suggests the potential for a few
embedded thunderstorms, so have included VCTS between 12z and 18z
as the initial surge of warm advection precip moves through. Winds
will be from the northeast at 5 to 10kt early this afternoon, then
will veer to the southeast and increase to between 15 and 20kt by
Saturday morning.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...BAK
LONG TERM...HJS
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
630 AM CDT FRI APR 29 2016
.SHORT TERM...
254 AM CDT
TODAY THROUGH TONIGHT...
WEAKENING CLOSED LOW OVER SOUTHERN WI/LAKE MICHIGAN WILL SHEAR
EASTWARD ACROSS THE GREAT LAKES REGION THIS MORNING...ALONG WITH
ASSOCIATED WEAK SURFACE LOW. SUBSIDENCE IN THE WAKE OF THIS
FEATURE IS INDICATED BY RISING HEIGHTS AND DRYING/WARMING OF THE
COLUMN FROM MID-MORNING INTO THIS EVENING. THIS SHOULD BRING AN
END TO ANY LINGERING LIGHT RAIN/DRIZZLE EARLY IN THE DAY. LIGHT
ANTICYCLONIC SFC WINDS WILL MAINTAIN COOL NORTHEAST FLOW...THROUGH
FORECAST SOUNDINGS DO INDICATE THAT SOME THINNING/EROSION OF LOW
CLOUDS IS POSSIBLE LATE IN THE DAY. ANY BRIEF PEAKS OF SUN WILL
NOT DO MUCH TO BOOST TEMPS HOWEVER. LOW LEVEL THERMAL FIELDS IN
GOOD AGREEMENT WITH GUIDANCE NUMBERS FOR AFTERNOON HIGHS...RANGING
FROM THE 40S AT THE LAKE SHORE TO THE MID/UPPER 50S ACROSS NORTH
CENTRAL IL...AND LOW/MID 60S FAR SOUTH COUNTIES.
WFO LOT FORECAST AREA BRIEFLY FINDS ITSELF BENEATH SHORT WAVE
RIDGE AXIS TONIGHT...ALTHOUGH INFLUENCE OF THE NEXT UPPER LOW
EMERGING FROM THE CENTRAL/SOUTHERN ROCKIES BEGINS OVERNIGHT
PRIMARILY IN THE FORM OF STRENGTHENING COOL EASTERLY WINDS ACROSS
THE CWA AND REDEVELOPMENT AND THICKENING OF CLOUD COVER AS THE
STATIONARY FRONTAL BOUNDARY CURRENTLY OVER THE SOUTHERN PLAINS AND
LOWER MISSISSIPPI VALLEY DEVELOPS NORTHWARD AS A WARM FRONT. SOME
OF THE AVAILABLE GUIDANCE SPREADS PRECIP INTO THE FAR SOUTHERN
COUNTIES OF THE CWA PRIOR TO SATURDAY MORNING...AND WHILE THE 00Z
WRF/21Z SREF MIGHT BE A BIT TOO FAR NORTH GIVEN THE SPREAD IN
MODEL OUTPUT...AT LEAST SOME LOW CHANCE POPS REMAIN APPROPRIATE
ACROSS THE SOUTH AFTER MIDNIGHT TONIGHT.
RATZER
&&
.LONG TERM...
254 AM CDT
SATURDAY THROUGH THURSDAY...
MAIN FORECAST FOCUS IS ON CONTINUATION OF COOL/WET WEATHER
THROUGH THE WEEKEND...AS PLAINS UPPER EVENTUALLY IS ABSORBED BY
EASTERN NORTH AMERICAN UPPER TROUGH.
UPPER LOW IS PROGGED TO BE OVER THE CENTRAL HIGH PLAINS SATURDAY
MORNING WITH SURFACE LOW PRESSURE OVER EASTERN KANSAS. MID-LEVEL
SHORT WAVE ENERGY IS DEPICTED ROTATING NORTHEASTWARD AROUND THE
UPPER LOW AND INTO THE REGION DURING THE DAY...AS 30-40 KT 850 MB
WINDS WORK TO LIFT THE ELEVATED WARM FRONTAL ZONE ACROSS CENTRAL
AND NORTHERN IL/IN. PERIOD OF INCREASED MOISTURE
CONVERGENCE/MOISTURE FLUX ON THE NOSE OF 1+ INCH PWAT AXIS
SUPPORTS HIGHEST POPS DURING THE DAY SATURDAY. PLUME OF 7-7.5 C/KM
700-500 MB LAPSE RATES AND WEAK COUPLED JET STRUCTURE ALOFT ALSO
POINT TO EMBEDDED ELEVATED THUNDER POTENTIAL ESPECIALLY ACROSS THE
SOUTHERN HALF OF THE CWA. GUIDANCE VARIES A BIT WITH PLACEMENT AND
AMOUNTS...THOUGH A GENERAL 0.90-1.25 INCH QPF AXIS IS NOTED ACROSS
THE CENTRAL/SOUTHERN PARTS OF THE CWA BY MIDNIGHT SATURDAY NIGHT.
PRECIP THREAT CONTINUES SATURDAY NIGHT AND INTO SUNDAY AS UPPER
LOW CIRCULATION SHEARS EASTWARD ALONG NEARLY STATIONARY ELEVATED
BAROCLINIC ZONE...THOUGH LIGHTER AMOUNTS AND COVERAGE ARE
ANTICIPATED AS OVERALL DYNAMICS WEAKEN AND DRIER AIR IS ENTRAINED
IN MID-LEVELS PER FORECAST SOUNDINGS. THE WEAKENING UPPER LOW
CIRCULATION EVENTUALLY IS ABSORBED INTO UPPER TROUGH OVER
NORTHEASTERN NORTH AMERICA SUNDAY NIGHT WITH DEEPER DRYING NOTED.
THICKER CLOUD COVER... PRECIP AND PERSISTENT EAST TO NORTHEAST LOW
LEVEL WINDS WILL KEEP TEMPERATURES BELOW NORMAL THROUGH THE
WEEKEND. LOW LEVEL THERMAL FIELDS SUPPORT GENERAL GUIDANCE TRENDS
OF HIGHS FROM THE 40S (NEAR THE LAKE) AND LOWER 50S ACROSS THE
NORTHERN CWA SATURDAY...WITH UPPER 50S IN THE SOUTH. 925-950 TEMPS
ARE ACTUALLY A LITTLE WARMER SUNDAY NORTH AND WITH POTENTIAL FOR
SOME PARTIAL CLEARING IN THE AFTERNOON HIGHS IN THE UPPER
50S/AROUND 60 APPEAR REASONABLE AWAY FROM COOL NORTHEAST FLOW OFF
THE LAKE.
FOR DAYS 4-7...MONDAY THROUGH THURSDAY...TROUGHING OVER EASTERN
NORTH AMERICA REMAINS DOMINANT THROUGH THE PERIOD WITH GENERAL
MODEL AGREEMENT IN BRINGING A RELATIVELY STRONG MID-LEVEL SHORT
WAVE AND ASSOCIATED SURFACE TROUGH ACROSS THE REGION IN NORTH-
NORTHWEST FLOW IN THE WEDNESDAY TIME FRAME. SLIGHTLY BELOW NORMAL
TEMPS LOOK TO PERSIST OUTSIDE OF TUESDAY-WEDNESDAY PERIOD WITH THE
APPROACH OF THE COLD FRONT...WITH THE TUESDAY NIGHT/WEDNESDAY
PERIOD ALSO HAVING THE BEST CHANCE FOR SOME SCATTERED SHOWERS WITH
FROPA. MAINTAINED A BLENDED GUIDANCE APPROACH WITH
TEMPS...GENERALLY LOW-MID 60S AWAY FROM LAKE MICHIGAN AND LOW-MID
50S NEAR THE LAKE WITH UPPER 60S/AROUND 70 TUESDAY-WEDNESDAY.
RATZER
&&
.AVIATION...
FOR THE 12Z TAFS...
LOW CEILINGS AND PATCHY FOG CONTINUE TO BE THE MAIN FORECAST
CHALLENGES THIS MORNING. IFR STRATUS DECK STRETCHES FROM CENTRAL
IL/IN NORTH TO NEAR CENTRAL WI EARLY THIS MORNING...WITH CLOUD BASES
ACROSS THE CHICAGO/ROCKFORD TERMINALS RANGING FROM 004-009. THERE IS
AN OFF CHANCE WE MAY LOSE ANOTHER HUNDRED FEET OR SO OVER THE NEXT 1-
2 HOURS BUT WITH SUNRISE AND DAYTIME HEATING EXPECT A GRADUAL
INCREASE IN CIGS WITH MVFR CONDITIONS RETURNING MID TO LATE THIS
MORNING...THEN SCATTERING TO VFR AT SOME POINT THIS AFTERNOON THOUGH
CONFIDENCE REMAINS LOW-MEDIUM IN SPECIFICS. LIGHT N/NNW WINDS EARLY
THIS MORNING WILL VEER TO THE NORTHEAST THROUGH THE MORNING HOURS
AND PICK UP TO AROUND 10 KT WHERE THEY SHOULD REMAIN THROUGH MOST OF
THE DAY. LOW PRESSURE LIFTING ACROSS THE PLAINS THIS EVENING AND
TONIGHT WILL CAUSE WINDS TO VEER FURTHER TO THE EAST LATE THIS
EVENING AND OVERNIGHT WITH INCREASINGLY GUSTY CONDITIONS EXPECTED ON
SATURDAY. SHOWERS WILL OVERSPREAD THE REGION ON SATURDAY...THOUGH
THE BEST CHANCES APPEAR TO BE BEYOND THE CURRENT TAF PERIOD.
BMD
&&
.MARINE...
246 AM CDT
HIGH PRESSURE WILL REMAIN JUST NORTH OF LAKE MICHIGAN TODAY
ALLOWING LIGHT FLOW ONCE AGAIN AND AFTERNOON LAKE BREEZES TO
DEVELOP. LOW PRESSURE IS PROGGED TO DEEPEN OVER THE PLAINS TONIGHT
INTO SATURDAY ALLOWING NORTHEAST WINDS TO PICK BACK UP INTO THE 15
TO 25 KT RANGE BY SATURDAY EVENING...WITH 30 KT WINDS NOT OUT OF
THE REALM OF POSSIBILITY. THE STRONG NORTHEAST BREEZE WILL PERSIST
INTO SUNDAY...THEN SHOULD DIMINISH AGAIN SUNDAY NIGHT INTO MONDAY
AS THE LOW DEPARTS EAST AND HIGH PRESSURE BUILDS BACK ACROSS THE
REGION. THE RIDGE AXIS WILL MOVE EAST OF LAKE MICHIGAN MONDAY
NIGHT AS ANOTHER LOW PRESSURE SYSTEM DEVELOPS OVER HUDSON BAY
ALLOWING WINDS TO TURN SOUTH TO SOUTHWESTERLY. THE LOW WILL DRIVE
A COLD FRONT ACROSS LAKE MICHIGAN AROUND MIDWEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
343 AM CDT FRI APR 29 2016
.SHORT TERM...(Today)
ISSUED AT 342 AM CDT Fri Apr 29 2016
Quiet conditions are expected across central and southeast Illinois
today. We will be between weather systems, although there will be a
fair amount of cloud cover across the area. Expect light winds and
slightly cooler than normal temperatures. Daytime highs will top out
in the 60s at most locations.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 342 AM CDT Fri Apr 29 2016
Deep trof over the western half of the CONUS will eject out another
low for the Midwest this weekend. Same kind of set up with a slow
moving system keeping much of the Midwest wet, and putting in excess
of an inch of rain anticipated for Central Illinois. A slower trend
in the models as the precip spreads from southwest to northeast
overnight tonight...mainly after midnight. The region sets up for
mainly a warm sector event from the developing low to the west.
Southerly flow of warm moisture feeding into the ongoing
precipitation for Saturday and Saturday night. Precip slowly
decreasing through Sunday night as the upper low finally progresses
through the region. Sunday night will have some clearing of the
precip with drier air wrapping around the system.
Models have had several problems...the 00z runs for the last three
nights have been different. Models are still not in agreement with
handling the pattern shift with the shearing out of the energy
remaining in the trof in the southwest. It seems an attempt at more
northwesterly flow ...but so far, the lack of gradient aloft is weak
at best, with no consistency for the energy trying to dig out a trof
over the Great Lakes. Remaining forecast is dry for now...with some
slight chances creeping in mid/end week. Temperatures are moderate
and holding near seasonal. Confidence in forecast for next week
remains weak and highly conditional.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1148 PM CDT Thu Apr 28 2016
Latest satellite images and observations show a lingering VFR OVC
CU cloud mass covering all but DEC late this evening, with
clearing just south of SPI and DEC. The southern edge of the
clouds has been starting a slow progression northward, in response
to a subtle northward shift in the trough axis. However, the
trough is expected to drift back southward later tonight and
Friday morning, putting the 850mb baroclinic zone directly across
our forecast area. The proximity of cooler air just to our north
and the frontal circulation in the baroclinic zone will help keep
cloud cover in the area more than sunshine. Therefore, we expect
cloud coverage to remain broken to overcast over a majority of
the area during this TAF period. SPI and DEC will have the best
chances at noticeable breaks in the cloud cover on Friday, with
shorter breaks for the northern TAF sites. Any breaks in the
clouds tonight will aid in fog formation, so will continue to
light fog of 3sm br for the northern TAFs. HRRR is not hitting fog
quite that hard at the terminal sites, but winds should become
light toward sunrise, helping tip the scales toward fog as
dewpoints linger in the upper 40s tonight.
Based on forecast soundings and HRRR output, we are still expecting
MVFR ceilings to develop from north to south tonight and linger
into Friday morning. IFR ceilings are projected to develop along
I-74 early Friday morning. Ceilings should improve with turbulent
mixing after sunrise helping lift the LCL. Winds stay fairly
light next 12-18 hours under the weak surface trough. WNW winds 4
to 7 kts will veer NW late tonight and then NE Friday morning and
eventually E during the afternoon. Wind speeds should remain in
the 5-10 kt range on Friday, with speeds increasing to 10-14kt
Friday evening ahead of approaching low pressure from the Plains.
Increasing isentropic lift will aid in mid-level saturation and
spotty showers after 03z Fri eve for SPI and DEC. Better chances
of rain will hold off until after this TAF valid period.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...BAK
LONG TERM...HJS
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
1228 AM CDT FRI APR 29 2016
.UPDATE...
901 PM CDT
SCATTERED LIGHT RAIN SHOWERS/DRIZZLE WILL CONTINUE INTO THE
OVERNIGHT HOURS AS AN UPPER LEVEL SHORTWAVE OVER NORTHERN
IOWA/SOUTHERN MINNESOTA MOVES EASTWARD. OTHERWISE COOL AND CLOUDY
CONDITIONS ARE EXPECTED WITH LOWERING CEILINGS AND
FOG...CONDITIONS THAT WILL LINGER INTO FRIDAY MORNING. THE
SHORTWAVE WILL EAST OF THE AREA FRIDAY RESULTING IN A DRY
DAY...BUT EXPECT A SLOW CLEARING TO CLOUDS WITH SOME SUN PEAKS
POSSIBLE LATE IN THE DAY.
KMD
&&
.SHORT TERM...
140 PM CDT
THROUGH FRIDAY...
ANOTHER COOL/CLOUDY AFTERNOON ACROSS THE REGION...WITH NORTHEAST
WINDS USHERING IN MUCH COOLER TEMPERATURES INTO NORTHEAST
ILLINOIS WITH TEMPS LOCKED IN THE MID/UPR 40S. FURTHER INLAND AWAY
FROM LAKE MICHIGAN TEMPS HAVE WARMED INTO THE MID/UPR
50S...ESPECIALLY ACROSS THE SOUTHWEST CWFA. THERE IS SOME BREAKS
IN THE THICK STRATUS ALONG THE SOUTHERN CWFA...AND WITH A WARM
FRONTAL BOUNDARY DRAPED ACROSS CENTRAL ILLINOIS SLOWLY LIFTING
NORTH...IT IS POSSIBLE SOME OF THE SOUTHERN PORTIONS OF THE
FORECAST AREA COULD TOUCH THE LOW/MID 60S BEFORE SUNSET THIS
EVENING.
THE LACK OF MECHANICAL MIXING THIS AFTERNOON/EVENING WILL ALLOW
CLOUDS TO REMAIN...WITH MINIMAL SCOURING OF THE STRATUS LAYER
PROGGED THROUGH THIS EVENING/OVERNIGHT. SOME OF THE GUIDANCE
CONTINUES TO PROG SCATTERED SHOWERS LIFTING NORTHEAST AHEAD OF THE
FRONTAL BOUNDARY THIS EVENING/OVERNIGHT...HOWEVER FEEL THAT
COVERAGE WILL REMAIN MINIMAL. IN ADDITION WITH THE LACK OF A LIFT
COMPONENT...EXPECT DROPLET SIZE TO BE MINIMAL WHICH COULD RESULT
IN PRECIP BEING MORE IN THE FORM OF DRIZZLE WITH PERHAPS SOME
LIGHT RAIN. AS THE OVERNIGHT PROGRESSES AND THE UPPER LEVEL SYSTEM
DRIFTS EAST...THE COVERAGE AND PROBABILITIES FOR PRECIP WILL
STEADILY DWINDLE FROM SOUTHWEST TO NORTHEAST. TEMPS OVERNIGHT WILL
ONLY COOL INTO THE LOW/MID 40S.
SHORTLY AFTER DAYBREAK FRI MID-LVL HEIGHTS WILL BE ON THE
RISE...WHICH WILL USHER IN DRIER AIR...HOWEVER WITH THE CONTINUED
LACK OF MIXING THE CHALLENGE IS HOW QUICKLY DO WE ERODE THE THICK
STRATUS LAYER. GUIDANCE HAS SLOWED THE RATE OF IMPROVEMENT UNTIL
MIDDAY...TO PERHAPS LATE AFTERNOON. THIS WILL END UP CONTROLLING
HIGHS FOR FRI...SO HAVE HELD ONTO THE TEMPS GENERALLY IN THE
MID/UPR 50S WITH PERHAPS SOME LOW 60S IN THE FAR SOUTHERN CWFA.
ELSEWHERE THE NORTHEAST FLOW OFF OF LAKE MICHIGAN WILL CONTINUE TO
SEE TEMPS REMAIN IN THE MID/UPR 40S AGAIN FRI.
BEACHLER
&&
.LONG TERM...
334 PM CDT
FRIDAY NIGHT THROUGH THURSDAY...
THE MAIN FORECAST CONCERN DURING THE EXTENDED PERIOD WILL BE WITH
THE INCREASING RAIN POTENTIAL AND THE CONTINUING UNSEASONABLY COOL
CONDITIONS THIS WEEKEND.
AN UPPER LEVEL TROUGH...CURRENTLY NOTED IN WATER VAPOR IMAGERY
SPINNING OVER THE SOUTHWESTERN CONUS...WILL SHIFT EAST-NORTHWARD
ACROSS THE CENTRAL HIGH PLAINS ON FRIDAY...WHILE INDUCING SURFACE
LOW PRESSURE ACROSS THE SOUTHERN AND CENTRAL PLAINS. THIS SYSTEM
WILL THEN SHIFT EASTWARD OVER THE CENTRAL STATES THROUGH THE
WEEKEND. MEANWHILE...A LARGE AND EXPANSIVE AREA OF SURFACE HIGH
PRESSURE WILL CONTINUE TO DOMINATE OVER SOUTHERN CANADA AND THE
UPPER MIDWEST AND GREAT LAKES REGION.
EAST TO NORTHEASTERLY SURFACE FLOW WILL CONTINUE FOR THE NEXT
SEVERAL DAYS...AND WILL LIKELY INCREASE BY SATURDAY AS THE SURFACE
LOW CONTINUES TO APPROACH MISSOURI. THIS WILL RESULT IN CONTINUED
CLOUD COVER AND UNSEASONABLE COOL CONDITIONS IN THE 40S TO 50S.
RAIN CHANCES LOOK TO INCREASE DURING THE DAY ON SATURDAY. THERE
CONTINUES TO BE TIMING DIFFERENCES AMONGST THE LATEST MODEL
GUIDANCE AS TO WHEN THE RAIN WILL DEVELOP OVER THE AREA ON
SATURDAY. HOWEVER...THE CHANCES OF RAIN BY SUNDAY AFTERNOON IS
QUITE HIGH AREA-WIDE AS A BAND OF FGEN LOOKS TO SET UP OVER THE
AREA IN ASSOCIATION WITH THE DEVELOPING 850 MB WARM FRONT. THIS
LOOKS TO SET UP A DECENT RAIN EVENT OVER THE AREA INTO SATURDAY
EVENING. IT APPEARS THE THREAT OF THUNDERSTORMS WILL REMAIN SOUTH
OF THE AREA...SO I CONTINUED TO LEAVE THE MENTION OUT OF THE
FORECAST. HOWEVER...WITH THE PROXIMITY WITH THE 850 FRONT TO MY
SOUTHERN CWA...I CANT RULE OUT THE POSSIBILITY OF AN EMBEDDED
STORM THERE SATURDAY AFTERNOON/EVENING. OTHERWISE...SOME LINGERING
SHOWERS LOOK TO CONTINUE AT TIMES INTO SUNDAY BEFORE ENDING...BUT
AT THIS TIME THE BEST WIDESPREAD RAIN POTENTIAL IS LOOKING TO BE
FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING.
TEMPERATURES DO LOOK TO BE ON A SLOW WARMING TREND EARLY NEXT
WEEK...WITH MAINLY DRY WEATHER EXPECTED. HOWEVER...THE UPPER LEVEL
WEATHER PATTERN NEXT WEEK DOES LOOK TO FAVOR BUILDING HEIGHTS OVER
THE PLAINS STATES...WHICH SHOULD FAVOR FALLING HEIGHTS AND
TROUGHING OVER THE EASTERN CONUS AND POSSIBLY PARTS OF THE GREAT
LAKES REGION AS WELL. THIS COULD RESULT IN SOME COOLER WEATHER
POSSIBLY DROPPING OVER THE REGION MID TO LATE WEEK.
HOWEVER...THERE IS A GOOD AMOUNT OF ENSEMBLE SPREAD WITH THE
EASTWARD EXTENT OF THE UPPER RIDGING AND WARMER ATMOSPHERE LATER
IN THE WEEK. THE CURRENT GFS IS MORE BULLISH IN BRING COOLER AIR
OVER THE REGION BEHIND A COLD FRONT LATER IN THE WEEK.
HOWEVER...THE LATEST ECWMF KEEPS THE COOLER AIR MASS TO OUR EAST.
KJB
&&
.AVIATION...
FOR THE 06Z TAFS...
LOW CEILINGS WILL PRESENT THE MAIN FORECAST CHALLENGE OVERNIGHT
THROUGH MIDDAY FRIDAY. CEILINGS HAVE ALREADY DROPPED TO 005-009
LATE THIS EVENING AND SHOULD CONTINUE TO SLOWLY TREND DOWN
OVERNIGHT ALONG WITH SOME FOG/BR REDUCING VISIBILITY TO 2-4 SM.
CONDITIONS SHOULD STEADILY IMPROVE AFTER SUNRISE FRIDAY MORNING
WITH CEILINGS LIFTING BACK TO MVFR MID TO LATE IN THE MORNING AND
EVENTUALLY SCATTERING OUT DURING THE AFTERNOON...THOUGH CONFIDENCE
IN SPECIFIC TIMING IS ONLY LOW TO MEDIUM AT THIS TIME. WINDS ARE
EXPECTED TO VEER TO THE NORTHEAST FRIDAY MORNING WITH WIND SPEEDS
PICKING UP TO AROUND 10 KT...THEN FURTHER INCREASING FRIDAY NIGHT
AS LOW PRESSURE DEEPENS ACROSS THE PLAINS.
BMD
&&
.MARINE...
351 PM CDT
ANOTHER STORM SYSTEM IS EXPECTED TO DEVELOP OVER THE PLAINS ON
FRIDAY...THEN SHIFT EASTWARD OVER THE MID MISSISSIPPI VALLEY TO THE
OHIO VALLEY...WHILE WEAKENING...THROUGH SUNDAY MORNING. OVERALL...A
PERSISTENT EAST-NORTHEASTERLY FLOW PATTERN IS EXPECTED OVER THE LAKE
THROUGH AT LEAST EARLY NEXT WEEK. ALTHOUGH THE FLOW WILL BE FAIRLY
LIGHT...THERE WILL BE PERIODS OF HIGH WIND SPEEDS. AS THE LOW
APPROACHES THE REGION ON SATURDAY...THE EAST-NORTHEASTERLY WINDS
WILL LIKELY INCREASE INTO THE 15 TO 25 KT RANGE LATE SATURDAY INTO
SUNDAY. THIS COULD AGAIN RESULT IN HIGH WAVES OVER THE SOUTHERN AND
WESTERN SHORES OF LAKE MICHIGAN...WHICH COULD SUPPORT ANOTHER SMALL
CRAFT ADVISORY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1148 PM CDT THU APR 28 2016
.UPDATE...
Issued at 910 PM CDT Thu Apr 28 2016
An elongated area of low pressure lingering across central
Illinois, roughly along I-74, will continue to be a focus for
spotty sprinkles or drizzle this evening. Precip should remain
north of I-74, based on radar trends and HRRR output. Some
clearing pushed across southern Illinois, as far north as I-72,
but a return of cloud cover is expected from the west the rest of
the night. As winds shift more northerly north of I-74, low clouds
will begin to advance southward, with some light fog possible as
well. The cloud cover will counteract some of the colder air
pushing into the area, with low temps bottoming out in the low to mid
40s towards Galesburg and Lacon, with low 50s south of I-70.
A few minor updates this evening were done on the weather, sky,
and temp/dewpoint grids. Updated information is already available.
&&
.SHORT TERM...(Tonight)
ISSUED AT 300 PM CDT Thu Apr 28 2016
Mid afternoon surface map shows weakening 1010 mb surface low
pressure over east central Iowa between Cedar Rapids and Iowa City,
with an occluded front lifting slowly ne over central IL/IN near I-
74. Isolated light showers were ne of I-74 isolated showers and
thunderstorms were over central IN around Indianapolis. Broken
cumulus clouds with bases 2.5-6k ft giving mostly cloudy skies over
central IL while partly sunny skies in southeast IL south of I-70.
Temps range from mid 50s from Macomb to Lacon north to the lower 70s
in southeast IL from I-70 south. Aloft a 555 dm 500 mb low was along
the western MN/IA border.
Latest forecast models take 555 dm 500 mb low east into central Lake
MI by Friday morning while weak surface low pressure tracks toward
west central IN by Friday morning. Expect abundant low clouds over
central IL tonight with mostly cloudy to overcast skies especially
from I-72 north with ceilings lowering to around 1k ft or lower
overnight. Will likely see some fog with vsbys 2-4 miles overnight
into early Friday morning. Less cloud cover in southeast IL tonight
with mostly clear to partly cloudy skies south of I-70. Lows
overnight range from lower 40s by Galesburg to lower 50s in
southeast IL from I-70 southeast. Winds to become NW and be fairly
light tonight under 10 mph.
.LONG TERM...(Friday through Thursday)
ISSUED AT 300 PM CDT Thu Apr 28 2016
Another slow moving low pressure area will move out of the plains
and toward the OH valley over the weekend. Pcpn will return to the
area beginning Fri night as the boundary sets up. As the low
pressure area moves along this boundary, south of the CWA, showers
and thunderstorms will dominate for Sat, with chances continuing for
Sat night and Sun. Pcpn will push east of the area on Sun night with
the highest chances of pcpn lingering in the east. Beyond this
system, an upper level cutoff low will sit over the southwest US
while a trough-pattern sets up over eastern Canada and down into
the Great Lakes region. These two things will keep the sfc
boundary south of the area, thereby keeping the CWA relatively dry
during next week.
Clouds and pcpn will keep temps slightly cooler/below normal over
the weekend. Cool/below normal temps will continue next week as well
since the boundary should remain south of the area through the
period and southerly return flow does not look like it returns until
possibly the first full weekend of May.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1148 PM CDT Thu Apr 28 2016
Latest satellite images and observations show a lingering VFR OVC
CU cloud mass covering all but DEC late this evening, with
clearing just south of SPI and DEC. The southern edge of the
clouds has been starting a slow progression northward, in response
to a subtle northward shift in the trough axis. However, the
trough is expected to drift back southward later tonight and
Friday morning, putting the 850mb baroclinic zone directly across
our forecast area. The proximity of cooler air just to our north
and the frontal circulation in the baroclinic zone will help keep
cloud cover in the area more than sunshine. Therefore, we expect
cloud coverage to remain broken to overcast over a majority of
the area during this TAF period. SPI and DEC will have the best
chances at noticeable breaks in the cloud cover on Friday, with
shorter breaks for the northern TAF sites. Any breaks in the
clouds tonight will aid in fog formation, so will continue to
light fog of 3sm br for the northern TAFs. HRRR is not hitting fog
quite that hard at the terminal sites, but winds should become
light toward sunrise, helping tip the scales toward fog as
dewpoints linger in the upper 40s tonight.
Based on forecast soundings and HRRR output, we are still expecting
MVFR ceilings to develop from north to south tonight and linger
into Friday morning. IFR ceilings are projected to develop along
I-74 early Friday morning. Ceilings should improve with turbulent
mixing after sunrise helping lift the LCL. Winds stay fairly
light next 12-18 hours under the weak surface trough. WNW winds 4
to 7 kts will veer NW late tonight and then NE Friday morning and
eventually E during the afternoon. Wind speeds should remain in
the 5-10 kt range on Friday, with speeds increasing to 10-14kt
Friday evening ahead of approaching low pressure from the Plains.
Increasing isentropic lift will aid in mid-level saturation and
spotty showers after 03z Fri eve for SPI and DEC. Better chances
of rain will hold off until after this TAF valid period.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...07
LONG TERM...Auten
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1249 AM EDT FRI APR 29 2016
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 300 PM EDT THU APR 28 2016
AFTER A BRIEF BREAK TONIGHT AND FRIDAY...ACTIVE WEATHER IS
EXPECTED TO CONTINUE INTO WEEKEND ACROSS CENTRAL INDIANA.
WEAK HIGH PRESSURE OVER THE GREAT LAKES IS EXPECTED TO BUILD
ACROSS INDIANA TONIGHT...PUSHING A COLD FRONT SOUTH TO KENTUCKY.
THIS WILL RESULT IN DRY WEATHER TONIGHT AND AGAIN ON FRIDAY.
LOW PRESSURE IS THEN EXPECTED TO DEVELOP OVER THE CENTRAL PLAINS
AND PUSH THE WARM FRONT BACK NORTH ACROSS CENTRAL INDIANA ON
SATURDAY. THIS WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS
BACK TO THE FORECAST.
YET ANOTHER LOW PRESSURE SYSTEM IS EXPECTED TO PASS ALONG THE
COLD FRONT AND ACROSS CENTRAL INDIANA ON SUNDAY...BRINGING YET
MORE CHANCES FOR SHOWERS AND STORMS.
DRY WEATHER WITH COOLER THAN NORMAL TEMPERATURES ARE EXPECTED
THROUGH MOST OF THE FIRST HALF OF NEXT WEEK. A COLD FRONT WILL
PROVIDE THE NEXT CHANCE FOR RAIN AND STORMS NEXT WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 913 PM EDT THU APR 28 2016
SURFACE TROUGHING EXPECTED TO LINGER ACROSS THE LOCAL AREA FOR MOST OF
THE NIGHT. SHORT TERM MODEL DATA SHOW SOME WEAK DISORGANIZED LIFT OVER
MAINLY THE NORTHERN ZONES INTO THE EARLY MORNING HOURS OF FRIDAY...SO
WILL KEEP IN SOME SMALL CHANCE POPS IN THOSE AREAS FOR LIGHT SHOWERS.
QUESTIONABLE HOW FAR SOUTH LOW CLOUD COVER CURRENTLY OVER NORTHEAST INDIANA
WILL GET TONIGHT...BUT APPEARS MOST OF THE LOW CLOUD COVER WILL RESIDE ON
THE NORTH SIDE OF THE SURFACE TROUGH.
PREVIOUS DISCUSSION FOLLOWS.
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS LOW PRESSURE OVER
SOUTHER CENTRAL INDIANA...LINGERING ALONG A FRONTAL BOUNDARY THAT
STRETCHES FROM EASTERN IOWA TO SOUTHERN OHIO AND WEST VIRGINIA.
RADAR SHOWS THAT SCT LIGHT RAIN SHOWERS/THUNDERSTORMS DEVELOPING
ACROSS CENTRAL INDIANA...ALONG AND NEAR THE BOUNDARY.
GIVEN LATEST RADAR TRENDS HRRR SEEMS A BIT OVER AGGRESSIVE WITH
PRECIP THIS AFTERNOON AND EARLY EVENING...HOWEVER THE OVERALL
TREND APPEARS IN PLACE WITH SCT DIURNAL CONVECTION ALONG AND NEAR
THE BOUNDARY LIFTING NORTHWARD THROUGH THE LATE AFTERNOON AND
PRECIP DIMINISHING DURING THE EVENING. FORECAST SOUNDINGS SHOW MID
LEVEL CAPPING BUILDING DURING THE EVENING HOURS...WHICH SHOULD
INHIBIT PRECIPITATION. HOWEVER...FORECAST SOUNDINGS AND TIME
HEIGHT SECTIONS CONTINUE TO SUGGEST SATURATED LOWER LEVELS WITH
DRY AIR ALOFT AND SUBSIDENCE. THIS COULD LEAD TO SOME DRIZZLE OR
FOG DURING THE OVERNIGHT HOURS...HOWEVER ANY PRECIPITATION SHOULD
BE RATHER LIGHT...WILL TRY AND HAVE MINIMAL POPS TO NO POPS. THUS
WILL TREND LOWS WARMER THAN MAVMOS GIVEN THE EXPECTED CLOUDS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 300 PM EDT THU APR 28 2016
FORECAST SOUNDINGS ON FRIDAY SUGGEST CONVECTIVE TEMPS IN THE
UPPER 70S WITH A GOOD MID LEVEL CAP IN PLACE. TIME HEIGHT SECTIONS
SHOW SATURATED LOWER LEVELS WITH SUBSIDENCE ALOFT. THUS WILL TREND
TOWARD A PARTLY SUNNY SKY. WITH LIGHT N-NW FLOW IN
PLACE...CONVECTIVE TEMPS ARE NOT EXPECTED TO BE REACHED. THUS WILL
TREND TOWARD A BLEND ON LOWS.
CLOUDS ARE EXPECTED TO INCREASE ON FRIDAY NIGHT AS SOUTHERLY FLOW
DEVELOPS ACROSS CENTRAL INDIANA DUE TO LOW PRESSURE DEVELOPING IN
THE CENTRAL PLAINS STATES. FORECAST SOUNDINGS SUGGEST AN
OVERRUNNING PATTERN OVERNIGHT...HOWEVER BEST FORCING LOOKS TO
ARRIVE AFTER 12Z SAT. THUS WILL TREND TOWARD CLOUD SKY ON FRIDAY
NIGHT...ALONG WITH LOWS WARMER THAN MAVMOS.
BETTER FORCING ARRIVES ON SATURDAY AS A SHORT WAVE IS EXPECTED TO
PUSH TOWARD INDIANA FROM THE SOUTHWEST. 305K ISENTROPIC SURFACE
SHOWS EXCELLENT UPGLIDE ON SATURDAY WITH SPECIFIC HUMIDITIES OVER
5 G/KG. FORECAST SOUNDINGS INDICATE A DEEPLY SATURATED COLUMN BY
18Z. THUS WILL TREND TOWARD HIGH POPS ALONG WITH TEMPERATURES
COOLER THAN MAVMOS GIVEN EXPECTED RAIN.
ADDITIONAL SHORT WAVES ARE LOOK POISED TO PUSH ACROSS INDIANA AND
THE OHIO VALLEY ON SATURDAY NIGHT AND AGAIN ON SUNDAY AFTERNOON
AND EVENING. MODEL CONTINUE TO SUGGEST THAT THE LINGERING FRONTAL BOUNDARY
WILL REMAIN IN THE AREA THROUGH SUNDAY. THUS WILL CONTINUE TO USE
POPS AT OR ABOVE MAVMOS AND TREND HIGHS COOLER AND LOWS WARMER
THAN GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 217 PM EDT THU APR 28 2016
AS THE LONG TERM BEGINS A FRONT WILL BE EXITING THE AREA AND AN
UPPER SHORTWAVE WILL BE MOVING THROUGH. COULD SEE SOME RAIN
SHOWERS HANGING AROUND GIVEN THIS. WITH THE FRONT TO THE SOUTH
WILL KEEP THUNDER OUT OF THE AREA. HIGH PRESSURE WILL BUILD IN
AFTER THAT AND SHOULD SEE MOSTLY DRY WEATHER MONDAY THROUGH
TUESDAY. BY WEDNESDAY ANOTHER FRONTAL SYSTEM COULD BRING A CHANCE
FOR SHOWERS. MODELS DISAGREE ON INSTABILITY WITH THAT SYSTEM SO
WILL KEEP A SLIGHT CHANCE FOR THUNDERSTORMS. TEMPERATURES SHOULD
BE NEAR NORMAL WITH HIGHS IN THE MID TO UPPER 60S AND LOWS IN THE
MID TO UPPER 40S.
&&
.AVIATION /DISCUSSION FOR THE 29/06Z TAFS/...
ISSUED AT 1244 AM EDT FRI APR 29 2016
VFR INITIALLY APPEARS LIKELY TO GIVE WAY TO MVFR OR WORSE
RESTRICTIONS OVERNIGHT...PARTICULARLY AT LAF/IND AND PERHAPS AT
HUF/BMG.
BOUNDARY IN PLACE ACROSS THE AREA WILL REMAIN. SOME QUESTION AS TO
POTENTIAL MOVEMENT...BUT EXPECT IT TO REMAIN QUASISTATIONARY
OVERNIGHT. EXPECT RESTRICTIONS TO DEVELOP...PARTICULARLY NORTH OF
THIS BOUNDARY WITH THE QUESTION BEING HOW LOW THINGS WILL GET.
LAMP GUIDANCE HAS CONTINUED TO BACK OFF A BIT. WILL TAKE LAF DOWN TO
IFR BORDERLINE AND IND DOWN TO 1500 FEET. HUF/BMG MAY ONLY BRIEFLY
BE MVFR IF AT ALL.
WINDS WILL BE GENERALLY NORTHERLY NORTH OF THE BOUNDARY AND WESTERLY
SOUTH. SPEEDS WILL DECREASE TO WELL BELOW 10KT OVERNIGHT. WINDS WILL
LIKELY BE VARIABLE MUCH OF THE TIME AT SEVERAL SITES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/JAS
SHORT TERM...PUMA
LONG TERM...CP
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS JACKSON KY
1048 PM EDT SAT APR 30 2016
.UPDATE...
ISSUED AT 1048 PM EDT SAT APR 30 2016
MADE ONE LAST UPDATE TO MAKE SURE THE ONGOING PRECIP WAS WELL
DEPICTED IN THE FORECAST...AS WELL AS TO TWEAK WHAT IS EXPECTED
DURING THE REST OF THE NIGHT. AS WAS PREVIOUSLY DISCUSSED...EVEN
HI RES MODELS ARE STILL HAVING A HARD TIME HANDLING THE ONGOING
PRECIP AS THE WARM FRONT MOVES NORTHWARD. THE HRRR CONTINUES TO
HAVE THE BEST HANDLE OVERALL...SO WENT WITH A MIX OF
OFFICIAL...HRRR...AND HAND TWEEKS TO COME UP WITH EXPECTED
SCENARIO. WE ARE CONTINUING TO SEE A DIMINISHMENT OF RAIN RATES
ACROSS EASTERN KY...SO PROBABLY NOT SEEING MUCH IN CLOUD LIGHTNING
AT THE MOMENT. HOWEVER...RAIN RATES COULD INCREASE...AND A FEW
HEAVIER SHOWERS TO OUR SW MAY MAKE IT INTO THE CWA...SO KEPT
MENTION OF ISOLATED THUNDER THROUGHOUT THE NIGHT AS A PRECAUTION.
IN ADDITION TO THE PRECIP UPDATE...ALSO MADE SURE THE TEMPS...DEW
POINTS...AND WINDS WERE WELL IN LINE WITH THE CURRENT CONDITIONS.
ALL CHANGES HAVE BEEN PUBLISHED AND SENT TO NDFD/WEB...THOUGH
CHANGES SHOULD NOT BE SIGNIFICANT ENOUGH TO WARRANT ANY FURTHER
ZFP UPDATES.
UPDATE ISSUED AT 855 PM EDT SAT APR 30 2016
SHOWERS ARE BEGINNING TO FILL INTO EASTERN KY FROM THE WEST AND
SOUTH AS A WARM FRONT CONTINUES TO LIFT THROUGH THE STATE. MOST OF
THE THUNDERSTORMS THAT HAD DEVELOPED TO OUR SOUTH THIS EVENING
HAVE SINCE WEAKENED AND ARE NOW JUST HEAVY SHOWERS.
HOWEVER...WOULDN/T RULE OUT SOME STRAY THUNDERSTORMS FROM SOME OF
THE HEAVIEST SHOWERS AS THEY MAKE THEIR WAY ACROSS EASTERN KY
OVERNIGHT. GIVEN THE LACK OF MODEL AGREEMENT...TRIED TO BASE NEAR
TERM UPDATED GRIDS ON CURRENT RADAR TRENDS...THEN BLENDED BACK
INTO THE HIRES MODELS THAT SEEM TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION. THIS WILL RESULT IN THE FIRST ROUND OF RAIN
SHOWERS AND ISOLATED THUNDER THROUGH THE NEXT FEW HOURS...THEN
ANOTHER HEAVIER BAND DEVELOPING ACROSS EAST CENTRAL KY AND MOVING
THROUGH THE CWA LATE TONIGHT/EARLY SUN MORNING. GIVEN THE
UNCERTAINTY...WILL CONTINUE TO MONITOR THROUGHOUT THE EVENING IN
CASE ANY FURTHER UPDATES NEED TO BE MADE.
THE OTHER MAIN CHANGE CAME WITH TEMPERATURES. GIVEN THE CLOUDS AND
RAIN...WE HAVE ACTUALLY REMAINED COOLER THAN ORIGINALLY
FORECASTED. THIS RESULTED IN NOT ONLY SOME TWEAKS TO THE CURRENT
TEMPS...BUT ALSO FOR THE DIURNAL CURVE THIS EVENING AND THROUGH
THE OVERNIGHT. AS IT STANDS...WE WILL LIKELY NOT SEE MUCH OF A
DROP DURING THE OVERNIGHT...ESPECIALLY WITH THE EXPECTED
WIDESPREAD RAIN AND CLOUD COVER...SO ONLY EXPECTING A FEW DEGREES
OF VARIATION FROM THE CURRENT ONGOING TEMPS.
ALL CHANGES HAVE BEEN SAVED AND SENT TO NDFD/WEB. A NEW FORECAST
PACKAGE WAS ALSO SENT OUT TO REFLECT THESE CHANGES.
UPDATE ISSUED AT 735 PM EDT SAT APR 30 2016
UNFORTUNATELY MODELS...EVEN HI RES...DO NOT HAVE A GOOD HANDLE ON
THE ONGOING SHOWERS AND THUNDERSTORMS ACROSS KY...TN...AND POINTS
SURROUNDING. HOWEVER...GIVEN THE CURRENT RADAR TRENDS...AN UPDATE
TO POPS AND WEATHER WAS DEEMED NECESSARY. AND MAY BE AGAIN IN THE
NEAR FUTURE DUE TO SHOWERS AND THUNDERSTORMS THAT HAVE NOW
DEVELOPED TO OUR SOUTH. TRIED TO USE THE BEST HI RES MODEL BLEND
AS A STARTING POINT AND THEN HAND TWEAKED GRIDS TO GET DESIRED
POP TREND. ALSO...CHANGED PROBABILITY WORDING TO COVERAGE WORDING
THROUGH THE OVERNIGHT SINCE PRECIP IS ONGOING. ALL CHANGES HAVE
BEEN SAVED AND SENT TO NDFD/WEB...AND NEW FORECAST ZONES WERE SENT
OUT AS WELL TO ADDRESS THE CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 400 PM EDT SAT APR 30 2016
CURRENT CONDITIONS ACROSS THE AREA FEATURE AN AREA OF SHOWERS AND
A FEW EMBEDDED THUNDERSTORMS MOVING NORTHEAST AHEAD OF A WARM
FRONT LIFTING NORTH THROUGH THE AREA. AS THIS AREA LIFTS THROUGH
TO THE NORTHEAST...A BREAK IN THE RAIN WILL OCCUR. AS SOUTHERLY
FLOW INCREASES AND THE FRONT SHIFTS NORTH INTO THE AREA...SOME
ADDITIONAL CONVECTION IS EXPECTED TO DEVELOP WITH SOME STORMS
PRODUCING HEAVY DOWNPOURS. WHILE SOME PONDING ON ROADS ARE
POSSIBLE...THE AREA IS FULLY GREENED UP AND WITH PWATS ONLY
REACHING JUST BELOW THE 2ND STANDARD DEVIATION...WILL NOT EXPECT
ANY FLOODING ISSUES TONIGHT. CONCERNING THE STRONG STORM
THREAT...AS THE FRONT APPROACHES TONIGHT...JUST ENOUGH FORCING AND
SHEAR WILL BE AVAILABLE FOR POSSIBLY A STRONG STORM OR TWO. IN
FACT TEMPS WILL REMAIN NEARLY STEADY THROUGH THIS EVENING AND
TONIGHT AS TEMPS ONLY DROP BACK INTO THE LOW 60S.
FOR SUNDAY...AS THE NEXT PIECE OF ENERGY MOVES THROUGH THE
MIDWEST AND INTO THE OH VALLEY...ANOTHER INSTANCE OF STRONG STORMS
WILL BE POSSIBLE. WITH EAST KENTUCKY BEING IN THE WARM
SECTOR...THE CAP OVER THE AREA WILL BE A BIT STOUT. HEADING INTO
THE DAY ON SUNDAY...IF INSTABILITY IS ENOUGH TO BREAK THE CAP AND
CAN OVERCOME THE LOW LEVEL DRY AREA...SOME STRONG STORMS ARE
POSSIBLE ON SUNDAY WITH HAIL AND DAMAGING WINDS THE THREAT. HAVE
MENTIONED THIS IN THE HWO.
HEADING INTO SUNDAY NIGHT...THE FRONT LOOKS TO STALL OUT OVER THE
EAST WITH SOME LINGERING SHOWERS INTO SUNDAY NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 311 PM EDT SAT APR 30 2016
THE EXTENDED PERIOD WILL FEATURE PERIODS OF ISOLATED TO SCATTERED
RAIN SHOWERS AND COOLER WEATHER THAT WHAT WE HAVE BEEN
EXPERIENCING THE PAST COUPLE OF WEEKS. THE MODELS ALL HAVE A LARGE
TROUGH OF LOW PRESSURE ALOFT DIVING OUT OF CANADA AND BASICALLY
SPINNING IN PLACE OVER THE SOUTHEASTERN GREAT LAKES REGION AND
SOUTHWESTERN NEW ENGLAND THROUGH OUT THE UPCOMING WORK WEEK. THE
WEATHER SYSTEM THAT WILL BRING SHOWERS AND STORMS TO EASTERN
KENTUCKY TODAY AND TOMORROW...WILL BE DEPARTING THE AREA MONDAY
AND MONDAY NIGHT. ONCE THAT SYSTEM MOVES OFF TO OUR EAST...A MUCH
LARGER AND MORE WELL DEVELOPED TROUGH IS FORECAST TO INFLUENCE THE
WEATHER OF EASTERN KENTUCKY THROUGH THE END OF THE WEEK. MULTIPLE
SHORT WAVES WILL MIGRATE AROUND THE WESTERN PERIPHERY OF THE UPPER
TROUGH...WHICH WILL BRING US PERIODS OF RAIN SHOWERS DURING THE
WEEK. THE RAIN WILL BE LIGHT AND SHOULD NOT PRESENT ANY MAJOR
ISSUES. WE WILL JUST BE IN STORE FOR A DAMP AND CLOUDY WEEK WITH
PERIODS OF SCATTERED RAIN SHOWERS.
TEMPERATURES DURING THE PERIOD WILL GENERALLY RUN AT OR BELOW
NORMAL AS THE TROUGH PULLS COOL MOIST AIR INTO THE REGION. DAY
TIME HIGHS WILL VARY FROM THE LOW TO MID 60S DURING THE RAINIEST
PERIODS...TO AROUND 70 ON THE LESS RAINY LESS CLOUDY DAYS.
OVERNIGHT LOWS WILL MOSTLY BE IN THE 40S ACROSS THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 745 PM EDT SAT APR 30 2016
A WARM FRONT IS CURRENTLY MAKING ITS WAY NORTHWARD THROUGH KY.
WHILE THIS IS NOT RESULTING IN ANY DRASTIC CHANGES TO THE WINDS OR
DEW POINTS...IT IS GENERATING AN AREA OF SHRA AND TSRA ACROSS
EASTERN TN WHICH ARE PUSHING NORTHWARD TOWARD EASTERN KY. ANOTHER
BATCH OF RAIN IS LOCATED ACROSS CENTRAL KY AND IS NOW MAKING ITS
WAY EASTWARD TOWARD THE TAF SITES AS WELL. TRIED TO TIME OUT THE
ONSET OF THE SHOWERS AND ANY THUNDER POTENTIAL /BEST THUNDER
SHOULD BE WITH ARRIVAL OF SOUTHERN STORMS AFTER 5Z/. UNFORTUNATELY
MODELS DO NOT HAVE A GREAT HANDLE ON THE ONGOING PATTERN...SO
RELIED ON UPSTREAM OBSERVATIONS FOR EXPECTED VIS AND CIG IMPACTS.
HOWEVER...SINCE MOST OF THE WEATHER WILL BE IMPACTING US DURING
THE OVERNIGHT...THESE PARAMETERS MAY NEED TO BE TWEAKED SOMEWHAT
AS IT NEARS. GENERALLY EXPECTING MVFR CIGS WITH SOME VIS DROPPING
INTO THE IFR CATEGORY IN THE HEAVIEST RAINS. THE SAME IS TRUE FOR
THE THUNDER POTENTIAL...SO GIVEN LOW CONFIDENCE ON IF THE BEST
CONVECTION WILL MAKE IT INTO OUR AREA...ONLY INCLUDED VCTS AT THIS
TIME.
A BREAK IN THE ACTION WILL LIKELY TAKE PLACE AFTER 8Z AS THE WARM
FRONT CONTINUES TO SHIFT NORTH. CONDITIONS WILL DEGRADE DURING THE
DAY TOMORROW AS THE NEXT DISTURBANCE PRODUCES MORE CONVECTION
TOMORROW AFTERNOON. EXACT IMPACTS AND TIMING OF THESE STORMS IS
STILL UNKNOWN. WINDS WILL BE LIGHT OUT OF THE EAST OVERNIGHT BEFORE
SHIFTING AROUND TO THE SOUTHWEST TOMORROW MORNING AND INCREASING
UP TO 10 KNOTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
949 PM CDT SAT APR 30 2016
.DISCUSSION...
THE WEAK SFC TROUGH CONTINUES TO MAKE SLOW PROGRESS ESE THIS
EVENING...AND NOW EXTENDS FROM NEAR A MWT...TO TXK...TO JUST E OF
ASL...TO LFK AND CXO LINE AS OF 0230Z. DID SEE A FEW TOWERS
DEVELOP ALONG THIS TROUGH JUST W OF SHV SHORTLY BEFORE
SUNSET...WITH EVEN A COUPLE OF ISOLATED SHRA HAVING RECENTLY
DEVELOPED ALONG THIS BNDRY IN SE CASS COUNTY TX...AS WELL AS OVER
TXK. THE SHORT TERM PROGS CONTINUE TO SUGGEST THIS BNDRY EASING A
BIT FARTHER SE INTO THE LOWER TOLEDO BEND COUNTRY AND NCNTRL LA
BEFORE PULLING UP STATIONARY LATE...WITH ISOLATED TO POSSIBLY
WIDELY SCT CONVECTION REDEVELOPING ALONG/JUST AHEAD OF THE BNDRY
WHERE THE AIR MASS REMAINS MODERATELY UNSTABLE. DID NOT MAKE ANY
CHANGES TO POPS TONIGHT...AND MADE ONLY MINOR CHANGES TO THE
CURRENT MIN TEMP FORECAST TO REFLECT THE CURRENT TRENDS. CAN/T
RULE OUT PATCHY FG DEVELOPING LATE ALONG/JUST AHEAD OF THE TROUGH
OVER DEEP E TX/NCNTRL LA...BUT WITH THE CURRENT CU FIELD AND
EVENTUALLY THE LOW STRATUS THAT SHOULD FORM LATE...AS WELL AS ANY
CONVECTION THAT MAY DEVELOP...WILL NOT ADD IT TO THE FORECAST
ATTM.
THE CURRENT FORECAST REMAINS ON TRACK AND NO ADDITIONAL CHANGES
ARE NEEDED THIS EVENING.
15
&&
.PREV DISCUSSION... /ISSUED 730 PM CDT SAT APR 30 2016/
DISCUSSION...
THE EVENING SFC ANALYSIS INDICATES A WEAK SFC TROUGH/PSEUDO-FRONT
EXTENDING IN A N-S LINE FROM EXTREME WRN AR S TO NEAR DEQ...TO
JUST E OF GGG...TO NEAR A LFK AND CXO LINE. SATELLITE TRENDS THIS
AFTERNOON AND A WALK OUTSIDE IN THE PARKING LOT REVEALS A FLAT CU
FIELD IN PLACE...DESPITE THE STRONG SFC-BASED INSTABILITY IN PLACE
AFTER TEMPS RECOVERED WELL INTO THE LOWER/MID 80S WITHIN THE HUMID
AIR MASS IN PLACE. THE WATER VAPOR IMAGERY ALSO SHOWS A BROAD SLUG OF
DRY AIR WRAPPING N AND E ACROSS THE MS VALLEY AROUND THE CLOSED
LOW OVER SW NE/NW KS...WITH VERY LITTLE IN THE WAY OF DEEP LYR
FORCING THIS FAR S OF THE CLOSED LOW. HOWEVER...GIVEN THE UNSTABLE
AIR MASS IN PLACE AND AMOUNT OF LOW LEVEL MOISTURE IN
PLACE...STILL CAN/T RULE OUT ISOLATED CONVECTION DEVELOPING LATER
THIS EVENING/OVERNIGHT NEAR/JUST E OF THE SFC TROUGH AS IT DRIFTS
ESE INTO THE LOWER TOLEDO BEND COUNTRY AND NCNTRL LA LATE BEFORE
BECOMING STATIONARY. THE SHORT TERM PROGS AND THE LATEST RUNS OF
THE HRRR ARE NOT VERY BULLISH AT ALL WITH CONVECTION DEVELOPING
NEAR/E OF THE TROUGH...THUS HAVE SCALED BACK POPS TONIGHT FOR
THESE AREAS. HAVE ALSO CANCELLED THE FLASH FLOOD WATCH THAT WAS IN
EFFECT FOR PORTIONS OF DEEP E TX/NCNTRL LA...AS THE FLOOD THREAT
HAS ENDED.
THE SFC TROUGH WILL FOCUS ADDITIONAL ISOLATED/SCT CONVECTION
DEVELOPMENT SUNDAY AS IT BEGINS TO SLOWLY LIFT BACK N ACROSS THE
REGION...ALTHOUGH RAINFALL AMOUNTS SHOULD STILL REMAIN LIGHT
THROUGH THE AFTERNOON OVER DEEP E TX/NCNTRL LA SUCH THAT FLOODING
SHOULD NOT BE A PROBLEM. THIS IS IN ADDITION TO THE FACT THAT
THESE AREAS DID NOT SEE AS MUCH RAIN AS AREAS FARTHER TO THE N
ACROSS NW LA/SW AR/MUCH OF E TX/SE OK. DID TONE DOWN POPS JUST A
TAD FOR THE FAR SRN ZONES...WITH THE GREATER COVERAGE IN
CONVECTION EXPECTED TO REMAIN JUST S OF THE REGION OVER SE
TX/CNTRL/SRN LA.
DID NOT ADJUST THE MIN TEMP FORECAST TONIGHT...BUT WILL RE-
EVALUATE DURING THE MID-EVENING DISCUSSION.
ZONE UPDATE/WATCH CANCELLATION ALREADY OUT...GRIDS WILL BE
AVAILABLE SHORTLY.
15
&&
PREV DISCUSSION... /ISSUED 658 PM CDT SAT APR 30 2016/
AVIATION...
FOR THE 01/00Z TAFS...A COLD FRONT WILL CONTINUE TO MOVE EASTWARD
ACROSS THE AREA AND WINDS WILL SHIFT TO THE NORTHWEST IMMEDIATELY
AFTER THE FROPA AND EVENTUALLY TO THE NORTHEAST AT MOST TAF SITES
BY THE END OF THE PERIOD. VFR CONDITIONS WILL PREVAIL INITIALLY
BUT LIGHT WINDS AND MOIST SOILS MAY ALLOW FOR LOW STRATUS AND
PATCHY FOG TO DEVELOP. THE FOG MAY BE DENSE IN SOME LOCATIONS. ANY
IFR/LIFR CONDITIONS THAT DEVELOP SHOULD GRADUALLY IMPROVE AFTER
SUNRISE AND VFR CONDITIONS SHOULD ONCE AGAIN PREVAIL AT ALL TAF
SITES BY 01/18Z. SOME CONVECTION MAY DEVELOP LATE SUNDAY
AFTERNOON BUT CURRENT THINKING IS THE BEST CHANCES FOR RAIN AT THE
TAF SITES WILL BE AFTER 02/00Z. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 66 82 64 75 / 20 20 70 70
MLU 69 84 66 74 / 30 30 70 80
DEQ 56 79 56 71 / 20 10 70 50
TXK 62 80 59 71 / 20 10 70 60
ELD 63 81 61 72 / 20 20 70 70
TYR 62 81 60 72 / 10 20 60 60
GGG 63 81 61 73 / 10 20 70 60
LFK 69 82 66 77 / 20 40 70 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
15
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
730 PM CDT SAT APR 30 2016
.DISCUSSION...
THE EVENING SFC ANALYSIS INDICATES A WEAK SFC TROUGH/PSEUDO-FRONT
EXTENDING IN A N-S LINE FROM EXTREME WRN AR S TO NEAR DEQ...TO
JUST E OF GGG...TO NEAR A LFK AND CXO LINE. SATELLITE TRENDS THIS
AFTERNOON AND A WALK OUTSIDE IN THE PARKING LOT REVEALS A FLAT CU
FIELD IN PLACE...DESPITE THE STRONG SFC-BASED INSTABILITY IN PLACE
AFTER TEMPS RECOVERED WELL INTO THE LOWER/MID 80S WITHIN THE HUMID
AIR MASS IN PLACE. THE WATER VAPOR IMAGERY ALSO SHOWS A BROAD SLUG OF
DRY AIR WRAPPING N AND E ACROSS THE MS VALLEY AROUND THE CLOSED
LOW OVER SW NE/NW KS...WITH VERY LITTLE IN THE WAY OF DEEP LYR
FORCING THIS FAR S OF THE CLOSED LOW. HOWEVER...GIVEN THE UNSTABLE
AIR MASS IN PLACE AND AMOUNT OF LOW LEVEL MOISTURE IN
PLACE...STILL CAN/T RULE OUT ISOLATED CONVECTION DEVELOPING LATER
THIS EVENING/OVERNIGHT NEAR/JUST E OF THE SFC TROUGH AS IT DRIFTS
ESE INTO THE LOWER TOLEDO BEND COUNTRY AND NCNTRL LA LATE BEFORE
BECOMING STATIONARY. THE SHORT TERM PROGS AND THE LATEST RUNS OF
THE HRRR ARE NOT VERY BULLISH AT ALL WITH CONVECTION DEVELOPING
NEAR/E OF THE TROUGH...THUS HAVE SCALED BACK POPS TONIGHT FOR
THESE AREAS. HAVE ALSO CANCELLED THE FLASH FLOOD WATCH THAT WAS IN
EFFECT FOR PORTIONS OF DEEP E TX/NCNTRL LA...AS THE FLOOD THREAT
HAS ENDED.
THE SFC TROUGH WILL FOCUS ADDITIONAL ISOLATED/SCT CONVECTION
DEVELOPMENT SUNDAY AS IT BEGINS TO SLOWLY LIFT BACK N ACROSS THE
REGION...ALTHOUGH RAINFALL AMOUNTS SHOULD STILL REMAIN LIGHT
THROUGH THE AFTERNOON OVER DEEP E TX/NCNTRL LA SUCH THAT FLOODING
SHOULD NOT BE A PROBLEM. THIS IS IN ADDITION TO THE FACT THAT
THESE AREAS DID NOT SEE AS MUCH RAIN AS AREAS FARTHER TO THE N
ACROSS NW LA/SW AR/MUCH OF E TX/SE OK. DID TONE DOWN POPS JUST A
TAD FOR THE FAR SRN ZONES...WITH THE GREATER COVERAGE IN
CONVECTION EXPECTED TO REMAIN JUST S OF THE REGION OVER SE
TX/CNTRL/SRN LA.
DID NOT ADJUST THE MIN TEMP FORECAST TONIGHT...BUT WILL RE-
EVALUATE DURING THE MID-EVENING DISCUSSION.
ZONE UPDATE/WATCH CANCELLATION ALREADY OUT...GRIDS WILL BE
AVAILABLE SHORTLY.
15
&&
.PREV DISCUSSION... /ISSUED 658 PM CDT SAT APR 30 2016/
AVIATION...
FOR THE 01/00Z TAFS...A COLD FRONT WILL CONTINUE TO MOVE EASTWARD
ACROSS THE AREA AND WINDS WILL SHIFT TO THE NORTHWEST IMMEDIATELY
AFTER THE FROPA AND EVENTUALLY TO THE NORTHEAST AT MOST TAF SITES
BY THE END OF THE PERIOD. VFR CONDITIONS WILL PREVAIL INITIALLY
BUT LIGHT WINDS AND MOIST SOILS MAY ALLOW FOR LOW STRATUS AND
PATCHY FOG TO DEVELOP. THE FOG MAY BE DENSE IN SOME LOCATIONS. ANY
IFR/LIFR CONDITIONS THAT DEVELOP SHOULD GRADUALLY IMPROVE AFTER
SUNRISE AND VFR CONDITIONS SHOULD ONCE AGAIN PREVAIL AT ALL TAF
SITES BY 01/18Z. SOME CONVECTION MAY DEVELOP LATE SUNDAY
AFTERNOON BUT CURRENT THINKING IS THE BEST CHANCES FOR RAIN AT THE
TAF SITES WILL BE AFTER 02/00Z. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 66 82 64 75 / 20 20 70 70
MLU 68 84 66 74 / 30 30 70 80
DEQ 55 79 56 71 / 20 10 70 50
TXK 60 80 59 71 / 20 10 70 60
ELD 62 81 61 72 / 20 20 70 70
TYR 61 81 60 72 / 10 20 60 60
GGG 63 81 61 73 / 10 20 70 60
LFK 67 82 66 77 / 20 40 70 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
120 AM EDT FRI APR 29 2016
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 354 PM EDT THU APR 28 2016
WV IMAGERY AND RAP ANALYSIS INDICATED MID/UPPER LEVEL RIDGING FROM
SASK THROUGH THE NRN LAKES ATOP A TROUGH FROM SW MN INTO SW WI. AT
THE SFC...NW LOW LEVEL FLOW PREVAILED INTO UPPER MI BETWEEN HIGH
PRES FROM NRN MANITOBA INTO NRN ONTARIO AND A TROUGH FROM ERN IA
INTO THE OH VALLEY. LIGHT RAIN FROM CNTRL WI INTO CNTRL LOWER MI WAS
SUPPORTED BY MID LEVEL FGEN/DEFORMATION AHEAD OF THE MID LEVEL LOW.
OTHERWISE...SUNSHINE WITH AREAS OF MID/HIGH CLOUDS REMAINED ACROSS
UPPER MI.
TONIGHT...ALTHOUGH SOME VERY LIGHT RAIN OR SPRINKLES MAY BE POSSIBLE
NEAR MNM LATE THIS AFTERNOON INTO THIS EVENING...VERY DRY LOW LEVEL
AIR WILL MINIMIZE ANY CHANCE FOR MEASURABLE PCPN. EVEN WITH
DIMINISHING WINDS...EXPECT ENOUGH MID/HIGH CLOUDS TO KEEP TEMPS FROM
DROPPING BELOW THE LOW 30S.
FRIDAY...HIGH PRES WILL CONTINUE TO DOMINATE AS A SHORTWAVE AND
ASSOCIATE LIGHT PCPN PASSES NORTH AND EAST OF LAKE SUPERIOR. A
WEAKENING NE GRADIENT FLOW WILL STILL BE BOOSTED BY LAKE SUPERIOR TO
KEEP TEMPS IN THE MID TO UPPER 40S NEAR LAKE SUPERIOR.
OTHERWISE...850-800 MB TEMPS AROUND -1C WILL SUPPORT INLAND TEMPS
INTO THE MID TO UPPER 50S. EXPECT PLENTY OF SUNSHINE AGAIN WITH FEW
MID/HIGH CLOUDS BUT MORE INLAND CU.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 403 PM EDT THU APR 28 2016
A FAIRLY PERSISTENT PATTERN APPEARS TO BE IN THE OFFING ACROSS THE
CONUS/SRN CANADA OVER THE NEXT 1-2 WEEKS. IN GENERAL...
RIDGING/POSITIVE HEIGHT ANOMALIES OF VARYING AMPLITUDE WILL BE THE
RULE ACROSS ROUGHLY THE W HALF OF CANADA WITH HEIGHT ANOMALIES
PEAKING EARLY NEXT WEEK. THIS WILL IN TURN FAVOR TROFFING OVER ERN
CANADA AND AT TIMES INTO THE ERN CONUS. THIS TROFFING WILL REACH
PEAK AMPLITUDE THE MIDDLE OF NEXT WEEK. MEANWHILE...IT APPEARS
ENERGY APPROACHING THE W COAST WILL SPLIT...SUPPORTING REDEVELOPMENT
OF A CNTRL/SRN ROCKIES TROF ON A FAIRLY REGULAR BASIS. THIS PATTERN
FAVORS BLO NORMAL PCPN FOR THE UPPER LAKES UNLESS THE ERN TROF
RELAXES SUFFICIENTLY TO ALLOW ENERGY EJECTING FROM THE MEAN ROCKIES
TROF TO LIFT FAR ENOUGH NE TO BRING MORE SIGNIFICANT PCPN INTO THE
UPPER LAKES. THUS...THERE IS LITTLE PCPN IN THE FCST FOR AT LEAST
THE NEXT 7 DAYS. ONE SHORTWAVE DROPPING THRU NRN ONTARIO OVER THE
WEEKEND MAY BE ACCOMPANIED BY SOME -SHRA...BUT WITH TRACK OF WAVE
JUST NE OF UPPER MI...PCPN IS UNLIKELY TO DEVELOP THIS FAR
S...ESPECIALLY WITH INSTABILITY LACKING. WOULD BE A DIFFERENT STORY
IF WE WERE MUCH FARTHER INTO THE WARM SEASON. DOWNSTREAM OF THE WRN
CANADA RIDGE WHICH REACHES PEAK AMPLITUDE EARLY NEXT WEEK...STRONGER
SHORTWAVE ENERGY WILL BE FORCED TO DROP FARTHER S INTO THE GREAT
LAKES REGION. AS A RESULT...ASSOCIATED COLD FROPA WHICH SHOULD OCCUR
TUE NIGHT WARRANTS LOW CHC POPS. AT THIS POINT...THAT`S THE ONLY CHC
OF RAIN FROM SAT THRU THU.
AS FOR TEMPS...THE EXPECTED PATTERN MOSTLY FAVORS NORMAL TO BLO
NORMAL TEMPS FOR UPPER MI. AWAY FROM THE INFLUENCE OF THE GREAT
LAKES...AN OVERALL DRY COLUMN ON MOST DAYS WILL SUPPORT RATHER LARGE
TEMP RANGES FROM NIGHTLY MINS TO AFTN MAXES. THRU THE WEEKEND...
TEMPS AT NIGHT WILL LIKELY DROP TO OR BLO FREEZING IN THE INTERIOR
COLDER AREAS. AFTN TEMPS SHOULD RISE TO AROUND 60F AWAY FROM THE
COOLING INFLUENCE OF THE GREAT LAKES. SOME WARMING WILL BEGIN
MON...BUT MORE SO TUE AS W TO SW FLOW DEVELOPS AHEAD OF APPROACHING
SHORTWAVE/COLD FRONT WHICH SHOULD ARRIVE TUE NIGHT. HOW WARM WILL
DEPEND ON THE TIMING OF THE COLD FRONT. COOLER WEATHER...ESPECIALLY
CLOSER TO LAKE SUPERIOR...WILL FOLLOW FOR WED WITH HIGH PRES
BUILDING TOWARD NRN ONTARIO. LOOKING FARTHER AHEAD...RECENT NAEFS
OUTLOOKS CONTINUE TO KEEP UPPER MI ON THE EDGE OF A LARGE AREA OF
ABOVE NORMAL TEMPS BEING FAVORED OVER WRN CANADA/NRN ROCKIES/NRN
PLAINS AND NORMAL TO BLO NORMAL TEMPS BEING FAVORED OVER SE CANADA.
SO...IT APPEARS TEMPS ACROSS UPPER MI WILL OVERALL REMAIN FAIRLY
CLOSE TO NORMAL HEADING INTO THE SECOND WEEK OF MAY.
WITH THE DEVELOPING DRY SPELL AND MOSTLY COOL WEATHER...ESPECIALLY
AT NIGHT...KEEPING GREENUP SLOW...FIRE WX CONCERNS WILL BE AN ISSUE
AT TIMES FOR AT LEAST THE NEXT 1-2 WEEKS. AS IT STANDS RIGHT
NOW...OVER THE NEXT 7 DAYS...TUE WILL LIKELY BE THE DAY OF MOST
CONCERN AS IT SHOULD BE THE WARMEST DAY WITH THE POTENTIAL FOR
BREEZY W TO SW WINDS AHEAD OF APPROACHING COLD FRONT. HOWEVER...WITH
THAT FROPA 5 DAYS OUT...TIMING OF THE FRONT WILL LIKELY CHANGE SOME
IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 119 AM EDT FRI APR 29 2016
VFR CONDITIONS WITH LIGHT WINDS WILL PERSIST THROUGH THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EDT THU APR 28 2016
LAKE SUPERIOR WILL REMAIN SITUATED BETWEEN HI PRES NEAR HUDSON BAY
AND A PAIR OF LO PRES SYSTEMS DRIFTING E THRU THE OHIO RIVER VALLEY/
FAR SOUTHERN GREAT LAKES THRU THIS WEEKEND. THIS PRES PATTERN FAVORS
CONTINUED NE WINDS UNDER 20 KTS FOR MOST OF LAKE SUPERIOR. THE BEST
CHANCE FOR STRONGER ENE WINDS UP TO 25 KTS WILL BE OVER THE WESTERN
LAKE...WHERE TERRAIN INFLUENCES WILL FUNNEL AND ACCENTUATE THE NE
FLOW...TODAY AND PERHAPS SAT WHEN THE PRES GRADIENT WILL BE
SHARPEST. AS A HI PRES RIDGE DRIFTS OVER THE UPPER LAKES SUN
NIGHT...WINDS SHOULD BECOME LIGHT. WSW WINDS UP TO 20 KTS WILL
PREVAIL EARLY NEXT WEEK AS THIS RIDGE AXIS SHIFTS TO THE S AHEAD OF
A COLD FRONT DROPPING THRU ONTARIO.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
948 AM MDT FRI APR 29 2016
.UPDATE...
FORECAST IN GOOD SHAPE WITH JUST A MINOR UPDATE TO PRECIP CHANCES
THIS MORNING. SATELLITE SHOWING AN UPPER LOW MOVING NORTHEAST OUT
OF THE FOUR CORNERS REGION THIS MORNING THAT IS ROTATING CLOUDS
NORTHWARD ACROSS WYOMING INTO SOUTHERN MONTANA. HOWEVER...BREAKS
IN THE CLOUDS ARE BEGINNING TO OCCUR ACROSS OUR EASTERN AND
WESTERN AREAS. GIVEN COLD AIR ALOFT...THE WARM SUN WILL ALLOW CU
TO DEVELOP OVER THE NEXT SEVERAL HOURS ACROSS THESE CLEARING
AREAS. IN ANY CASE...WE SHOULD STILL SEE SOME PEAKS OF SUNSHINE AT
TIMES TODAY...SOMETHING WE HAVE NOT SEEN MUCH IF ANY OF DURING THE
PAST 6 DAYS. HI RES MODELS ARE SHOWING SHOWERS DEVELOPING ACROSS
THE CENTRAL AND EASTERN AREAS THIS AFTERNOON AND THIS IS QUITE
POSSIBLE GIVEN THAT ANY SUNSHINE WILL MAKE THINGS A BIT UNSTABLE.
THEREFORE...I HAVE ADDED A SLIGHT SHOWER CHANCE TO THE FORECAST
FOR THIS AFTERNOON FOR AREAS AROUND BILLINGS EASTWARD TO THE
DAKOTA BORDERS. AFTERNOON TEMPERATURES LOOK TO BE ABOUT 10 TO 12
DEGREES WARMER THAN YESTERDAY BUT STILL WELL BELOW NORMAL FOR THIS
TIME OF YEAR WITH READINGS IN THE UPPER 40S TO LOWER 50S. HOOLEY
&&
.SHORT TERM...VALID FOR TDY AND SAT...
MAIN CHANGE TO THE SHORT-TERM FORECAST WAS TO REDUCE POPS THROUGH
THE PERIOD. UPPER LOWS WERE SEEN ON WATER VAPOR IMAGERY THIS
MORNING...OVER W MT AND THE FOUR-CORNERS REGION. THE W MT LOW
WASHES OUT WHILE THE FOUR-CORNERS LOW MOVES ENE TODAY SENDING ONLY
WEAK VORTICITY INTO THE REGION. MOISTURE PROGS SHOWED ONLY LIMITED
MOISTURE AND LIMITED QPF CONFINED TO MAINLY THE MOUNTAINS. MODELS
ALSO WERE OVERDOING THEIR QPF OVER WY EARLY THIS MORNING. THUS
BACKED OFF POPS TODAY AND CONFINED THEM TO OVER AND NEAR THE
MOUNTAINS. THE WRF AND CONVECTIVE OUTLOOK SHOWED THE POSSIBILITY
OF THUNDER OVER THE SW MOUNTAINS THIS AFTERNOON...SO ADDED THIS TO
THE FORECAST. HRRR SHOWED POSSIBLE FOG FORMATION W OF KBIL THIS
MORNING AND THERE WAS A BREAK IN THE CLOUDS ON SATELLITE WITH LOW
DEWPOINT DEPRESSIONS OVER KBIL...SO WILL NEED TO WATCH FOR THIS
POSSIBILITY.
THE FOUR-CORNERS LOW WILL MOVE INTO KS/NE TONIGHT AND ENERGY WILL
BE LIMITED OVER THE AREA. MODELS DID TRY TO BRING SOME MOISTURE N
TOWARD THE AREA AROUND THE LOW. QPF CONTINUED TO BE CONFINED TO
AREAS OVER AND NEAR THE MOUNTAINS SO WENT WITH THIS SOLUTION.
BROUGHT SMALL CHANCES INTO FAR SE MT TO MATCH UP WITH NEIGHBORS.
SAT WAS SIMILAR TO TONIGHT WITH THE UPPER LOW OVER KS/NE AND A
RIDGE SETTLING N OF THE LOWER PRESSURE OVER THE FORECAST AREA
FORMING A REX BLOCK. TRIMMED BACK INHERITED POPS TO LOW CHANCES
OVER WESTERN AND CENTRAL AREAS. HAD HIGHEST CHANCES OVER SHERIDAN
COUNTY...CLOSEST TO GOOD MOISTURE. EASTERLY UPSLOPE FLOW WILL AID
PRECIPITATION CHANCES ON SAT.
HIGH PRESSURE ALOFT STRENGTHENS OVER THE AREA SAT NIGHT AND
MOISTURE GETS SUPPRESSED S. HAD POPS OVER AND NEAR THE MOUNTAINS
IN THE EVENING THEN LOWERED THEM OVERNIGHT.
HIGHS BOTH DAYS WILL BE IN THE 50S WITH MIXING TO ONLY AROUND 800
MB AND 850 TEMPERATURES OF +4 TO +8 DEGREES C. ARTHUR
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
AN AREA OF UPPER LEVEL HIGH PRESSURE MOVING INTO ALBERTA WILL
BEGIN TO DRY THE AIRMASS OUT ON SUNDAY WITH LOW LEVEL EASTERLY
FLOW KEEPING TEMPERATURES BELOW NORMAL ON SUNDAY BUT WARMING TO
NORMAL ON MONDAY. SURFACE FLOWS BECOME A BIT MORE SOUTHERLY ON
TUESDAY AND THE REST OF THE WEEK PROMOTING BETTER MIXING AND
TEMPERATURES MOVING INTO THE 70S OR BETTER OR THE LATTER HALF OF
THE WEEK. THE AREA OF HIGH PRESSURE EVOLVES INTO MORE OF A LONG
WAVE RIDGE ASSURING DRY WEATHER THROUGH THE PERIOD. WINDS LOOK
RELATIVELY LITE. BORSUM.
&&
.AVIATION...
MID LEVEL CLOUD COVER WILL REMAIN EXTENSIVE ACROSS THE REGION
TODAY. ISOLATED SHOWER ACTIVITY IS EXPECTED ACROSS THE REGION.
EXPECT MOUNTAIN OBSCURATIONS ACROSS SOUTHERN MONTANA AND NORTHERN
WYOMING TODAY INTO TONIGHT. RMS/HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SAT SUN MON TUE WED THU
-------------------------------------------------------
BIL 053 037/053 037/059 037/065 041/071 044/074 046/074
2/W 12/W 10/B 01/U 10/U 00/U 11/U
LVM 051 034/051 034/056 032/065 036/072 039/073 041/073
2/W 32/W 21/B 00/U 11/U 11/U 11/B
HDN 055 035/056 034/061 035/066 038/071 039/075 041/074
2/W 12/W 10/B 01/U 10/U 00/U 11/U
MLS 056 038/059 036/063 037/067 041/071 044/074 045/073
2/W 11/B 10/U 00/U 00/U 00/U 11/U
4BQ 051 035/055 032/059 034/064 038/070 040/073 042/072
2/W 22/W 10/B 01/U 11/U 00/U 11/U
BHK 053 035/057 033/061 035/065 038/069 040/070 041/069
2/W 11/B 10/U 00/U 00/U 00/U 11/U
SHR 052 035/051 032/056 032/060 035/066 036/070 038/071
2/W 25/W 31/B 01/U 11/U 00/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
216 AM MDT FRI APR 29 2016
.SHORT TERM...VALID FOR TDY AND SAT...
MAIN CHANGE TO THE SHORT-TERM FORECAST WAS TO REDUCE POPS THROUGH
THE PERIOD. UPPER LOWS WERE SEEN ON WATER VAPOR IMAGERY THIS
MORNING...OVER W MT AND THE FOUR-CORNERS REGION. THE W MT LOW
WASHES OUT WHILE THE FOUR-CORNERS LOW MOVES ENE TODAY SENDING ONLY
WEAK VORTICITY INTO THE REGION. MOISTURE PROGS SHOWED ONLY LIMITED
MOISTURE AND LIMITED QPF CONFINED TO MAINLY THE MOUNTAINS. MODELS
ALSO WERE OVERDOING THEIR QPF OVER WY EARLY THIS MORNING. THUS
BACKED OFF POPS TODAY AND CONFINED THEM TO OVER AND NEAR THE
MOUNTAINS. THE WRF AND CONVECTIVE OUTLOOK SHOWED THE POSSIBILITY
OF THUNDER OVER THE SW MOUNTAINS THIS AFTERNOON...SO ADDED THIS TO
THE FORECAST. HRRR SHOWED POSSIBLE FOG FORMATION W OF KBIL THIS
MORNING AND THERE WAS A BREAK IN THE CLOUDS ON SATELLITE WITH LOW
DEWPOINT DEPRESSIONS OVER KBIL...SO WILL NEED TO WATCH FOR THIS
POSSIBILITY.
THE FOUR-CORNERS LOW WILL MOVE INTO KS/NE TONIGHT AND ENERGY WILL
BE LIMITED OVER THE AREA. MODELS DID TRY TO BRING SOME MOISTURE N
TOWARD THE AREA AROUND THE LOW. QPF CONTINUED TO BE CONFINED TO
AREAS OVER AND NEAR THE MOUNTAINS SO WENT WITH THIS SOLUTION.
BROUGHT SMALL CHANCES INTO FAR SE MT TO MATCH UP WITH NEIGHBORS.
SAT WAS SIMILAR TO TONIGHT WITH THE UPPER LOW OVER KS/NE AND A
RIDGE SETTLING N OF THE LOWER PRESSURE OVER THE FORECAST AREA
FORMING A REX BLOCK. TRIMMED BACK INHERITED POPS TO LOW CHANCES
OVER WESTERN AND CENTRAL AREAS. HAD HIGHEST CHANCES OVER SHERIDAN
COUNTY...CLOSEST TO GOOD MOISTURE. EASTERLY UPSLOPE FLOW WILL AID
PRECIPITATION CHANCES ON SAT.
HIGH PRESSURE ALOFT STRENGTHENS OVER THE AREA SAT NIGHT AND
MOISTURE GETS SUPPRESSED S. HAD POPS OVER AND NEAR THE MOUNTAINS
IN THE EVENING THEN LOWERED THEM OVERNIGHT.
HIGHS BOTH DAYS WILL BE IN THE 50S WITH MIXING TO ONLY AROUND 800
MB AND 850 TEMPERATURES OF +4 TO +8 DEGREES C. ARTHUR
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
AN AREA OF UPPER LEVEL HIGH PRESSURE MOVING INTO ALBERTA WILL
BEGIN TO DRY THE AIRMASS OUT ON SUNDAY WITH LOW LEVEL EASTERLY
FLOW KEEPING TEMPERATURES BELOW NORMAL ON SUNDAY BUT WARMING TO
NORMAL ON MONDAY. SURFACE FLOWS BECOME A BIT MORE SOUTHERLY ON
TUESDAY AND THE REST OF THE WEEK PROMOTING BETTER MIXING AND
TEMPERATURES MOVING INTO THE 70S OR BETTER OR THE LATTER HALF OF
THE WEEK. THE AREA OF HIGH PRESSURE EVOLVES INTO MORE OF A LONG
WAVE RIDGE ASSURING DRY WEATHER THROUGH THE PERIOD. WINDS LOOK
RELATIVELY LITE. BORSUM.
&&
.AVIATION...
MID LEVEL CLOUD COVER WILL REMAIN EXTENSIVE ACROSS THE REGION INTO
THE MORNING HOURS. THERE IS A CHANCE FOR PATCHES OF FOG DEVELOPING
IS IN LOWER AREAS ALONG THE RIVERS BUT DO NOT EXPECT TERMINAL
SITES TO BE IMPACTED. ISOLATED SHOWER ACTIVITY IS EXPECTED THIS
AFTERNOON OVER THE MOUNTAINS BUT REMAINING OVER THE HIGH TERRAIN.
BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SAT SUN MON TUE WED THU
-------------------------------------------------------
BIL 053 037/053 037/059 037/065 041/071 044/074 046/074
1/B 12/W 10/B 01/U 10/U 00/U 11/U
LVM 051 034/051 034/056 032/065 036/072 039/073 041/073
2/W 32/W 21/B 00/U 11/U 11/U 11/B
HDN 055 035/056 034/061 035/066 038/071 039/075 041/074
1/B 12/W 10/B 01/U 10/U 00/U 11/U
MLS 056 038/059 036/063 037/067 041/071 044/074 045/073
1/B 11/B 10/U 00/U 00/U 00/U 11/U
4BQ 051 035/055 032/059 034/064 038/070 040/073 042/072
1/E 22/W 10/B 01/U 11/U 00/U 11/U
BHK 053 035/057 033/061 035/065 038/069 040/070 041/069
1/E 11/B 10/U 00/U 00/U 00/U 11/U
SHR 052 035/051 032/056 032/060 035/066 036/070 038/071
1/B 25/W 31/B 01/U 11/U 00/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1227 PM CDT FRI APR 29 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT FRI APR 29 2016
TODAY AND TONIGHT...THE RAP IS TRACKING THE POWERFUL UPPER LOW
ACROSS THE 4 CORNERS REGION AND BRINGING RAIN AND SNOW INTO SWRN NEB
BY LATE AFTERNOON. THIS IS CLOSE TO THE COOLER NAM SOLN. IN FACT THE
RAP SHOWS RAIN AND SNOW EAST OF HIGHWAY 83 AT 00Z THIS EVENING WITH
ALL SNOW ACROSS SWRN NEB. DESPITE THIS THE RAP KEEPS ACCUMULATING
SNOW ACCUMULATIONS LIGHT...WEST OF HIGHWAY 61 BUT WITH HEAVY
ACCUMULATIONS OVER THE COLORADO PLAINS. THE FORECAST TODAY FOLLOWS A
BLEND OF THE RAP AND 4 BIAS CORRECTED GUIDANCE DATASETS FOR HIGHS IN
THE 40S.
THE BLEND OF 4 BIAS CORRECTED GUIDANCE DATASETS PRODUCES LOWS IN THE
30S TO NEAR 40 TONIGHT. IF THIS TEMPERATURE FORECAST IS CLOSE...THEN
SNOW SHOULD BECOME WIDESPREAD ACROSS THE CNTL AND WRN SANDHILLS.
NOTE THE RAP IS FORECASTING VSBY LESS THAN 1/4 MILE AT 00Z AND THIS
IS DISTURBING AS IT REPRESENTS HEAVY SNOW. IT MIGHT BE BEST TO
REVISIT THE RAP MODEL AFTER THE 12Z UPPER AIR DATA INGEST IS
COMPLETE AROUND 13Z OR 14Z.
A WINTER WEATHER ADVISORY IS IN PLACE FOR THE SANDHILLS TONIGHT AND
SATURDAY. SNOW IS UNDERWAY IN LIMON THIS MORNING AND SNOW LEVELS
ACROSS THE SANDHILLS SHOULD FALL TO AROUND 3500 FEET TONIGHT.
HEAVY RAIN IS FORECAST FOR TONIGHT FOR AREAS EAST OF HIGHWAY 83. THE
BLENDED SOLN PRODUCES AROUND 1.5 INCHES OF RAINFALL IN 12 HOURS
TONIGHT WHICH MAY PRODUCE MINOR FLOODING. THE DOWN-SCALED NAM AND TO
A LESSER EXTENT THE ARW AND NMM REFLECTIVITY PRODUCTS SHOW
CONVECTION JUST EAST OF THE FCST AREA TONIGHT. THE NAM12 INDICATES
ELEVATED CAPE ACROSS SCNTL NEB EAST OF THE FCST AREA ALSO. ALL OF
THIS CONVECTION WILL BE FEEDING NORTHWEST INTO A DEFORMATION ZONE
ACROSS THE SANDHILLS TONIGHT.
LASTLY...A FAIRLY WIDESPREAD SEVERE WEATHER EVENT IS EXPECTED ACROSS
THE MID SOUTH WHICH SHOULD MOMENTARILY BLOCK OR DEFLECT MOISTURE
TRANSPORT INTO THE STORM ACROSS NEB. THE MODELS TEND TO MIS-FORECAST
THIS FEATURE AND CONTINUE TO FORECAST HEAVY RAIN OR SNOW FARTHER
NORTH WHICH SOMETIMES DOES NOT MATERIALIZE. THUS THE PROSPECT OF
HEAVY RAIN AND SNOW ACROSS THE FCST AREA IS SOMEWHAT UNCERTAIN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 29 2016
MID RANGE...SATURDAY AND SUNDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION AS THE POTENT UPPER LOW SLOWLY
CROSSES THE CENTRAL PLAINS.
SATURDAY... LOWERED MAX TEMPS ANOTHER DEGREE OR SO AS GUIDANCE HAS
BEEN OVERSHOOTING TEMPS LATELY. CURRENT FORECAST HIGHS ARE NOW NEAR
40F WEST AND LOWER/MID 40S EAST... WHICH IS ABOUT 5 DEGREES BELOW
MAV/MET BUT SLIGHTLY ABOVE ECS. WENT AHEAD AND INTRODUCED ALL SNOW
FOR THE PANHANDLE AND FAR WESTERN SANDHILLS THROUGH 18Z. NAM AND GFS
FORECAST SOUNDINGS AGREE ON SATURATION IN THE DGZ THROUGHOUT THE
MORNING... INDICATING ICE INITIATION IN THE CLOUD LAYER. NAM KEEPS
VIRTUALLY THE ENTIRE TEMP PROFILE AT OR BELOW FREEZING AT KAIA AND
KOGA... WHICH SUGGESTS LITTLE TO NO MELTING. IN ADDITION...
APPRECIABLE LIFT EXISTS AS SHOWN BY NEGATIVE OMEGA IN SOUNDINGS...
ISENTROPIC UPGLIDE AT 295K AND 300K... AND NEARLY UPRIGHT AGEO
CIRCULATION IN CROSS SECTIONS OF THE SANDHILLS. THE H3 JET IS ALSO
NEARBY... PROVIDING EXTRA DIVERGENCE ALOFT. THE POTENTIAL FOR
MODERATE SNOW EXISTS... BUT THE QUESTION IS HOW MUCH SNOW ACTUALLY
ACCUMULATES DUE TO RELATIVELY WARM GROUND TEMPS. CONFIDENCE IS LOW
FOR HEAVY SNOW... OR AT LEAST HEAVY ENOUGH TO COMPENSATE AND PILE UP
ON NON GRASSY SURFACES. FARTHER EAST ALONG THE HWY 83 CORRIDOR...
TEMP PROFILES HUG THE FREEZING LINE FOR THE LOWEST 200HPA... RAISING
THE POSSIBILITY OF MELTING SNOW. GIVEN SLIGHTLY WARMER MIN TEMPS...
KEPT PTYPE AS RASN. ENOUGH LOW LEVEL WARMING SHOULD TAKE PLACE
AFTN/EVE TO SWITCH PRECIP TO ALL RAIN FOR THE ENTIRE CWA. FLIPPED
BACK TO RASN SAT NIGHT ACROSS THE WEST AND SNOW IN THE PANHANDLE.
MOISTURE CONTENT WILL BE LOWER AND THE FORCING WEAKER... SO
ACCUMULATING SNOW IS NOT AS BIG A CONCERN AS SAT AM.
SUNDAY... MADE LITTLE CHANGE TO MAX TEMPS AS WEAK WAA RESUMES.
HOWEVER... CONTINUED BKN/OVC CONDITIONS AND NORTH/NORTHEAST WINDS
WILL STILL LIMIT HIGHS TO THE LOWER 50S. CUT POPS BACK AS THE MID
LEVELS START TO DRY OUT. SOME LIFT AND RELATIVELY STEEP LAPSE RATES
STILL EXIST IN THE LOW LEVELS AND SOME WEAK FGEN FORCING AT H7
REMAINS... SO CANT ENTIRELY RULE OUT A SHOWER... MAINLY SOUTHERN AND
WESTERN PORTIONS OF THE CWA.
LONG RANGE...MONDAY THROUGH THURSDAY... A WEAK SHORTWAVE TRAVERSES
THE AREA MONDAY... BUT THE BEST MOISTURE IS ACROSS SOUTHWEST
NEBRASKA. SCHC POPS CONFINED GENERALLY ALONG/SOUTH OF I-80 AM/EARLY
PM. MIDWEEK... AN UPPER LEVEL RIDGE AND SURFACE HIGH PRESSURE
CONTROL THE PATTERN OVER THE ROCKIES AND PLAINS. SIGNIFICANT WARMING
IS DUE WITH DOWNSLOPE FLOW ON TUESDAY AND A THERMAL RIDGE
APPROACHING THE AREA WEDNESDAY. H85 TEMPS EXCEED 10C FOR WESTERN AND
CENTRAL NEB WED AND CLOSE TO 15C PANHANDLE. THE UPPER RIDGE AXIS IS
ON OUR DOORSTEP THURSDAY WHILE THE H85 RIDGE AXIS BISECTS THE
AREA... FLIPPING THE FLOW TO SOUTHERLY. GFS A LITTLE QUICKER AND
WARMER THAN EURO WITH THIS FEATURE... BUT HIGHS SHOULD HAVE NO
PROBLEM REACHING THE 70S ONCE AGAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1222 PM CDT FRI APR 29 2016
MODELS ARE IN GOOD AGREEMENT AND CONFIDENCE IS INCREASING WHERE A
PROLONGED SLOW MOVING SPRING STORM WILL BRING A MIXTURE OF RAIN
AND SNOW THROUGH 18Z SATURDAY. MARGINAL VFR CONDITIONS WILL LOWER
TO IFR CONDITIONS THIS EVENING...AND DOWN TO LIFR FLIGHT
CATEGORIES FOR OVERNIGHT AND BEYOND.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM CDT /6 PM MDT/ THIS EVENING TO
7 PM CDT /6 PM MDT/ SATURDAY FOR NEZ004-022>024-035-036-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...SNIVELY
AVIATION...KECK
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
629 AM CDT FRI APR 29 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT FRI APR 29 2016
TODAY AND TONIGHT...THE RAP IS TRACKING THE POWERFUL UPPER LOW
ACROSS THE 4 CORNERS REGION AND BRINGING RAIN AND SNOW INTO SWRN NEB
BY LATE AFTERNOON. THIS IS CLOSE TO THE COOLER NAM SOLN. IN FACT THE
RAP SHOWS RAIN AND SNOW EAST OF HIGHWAY 83 AT 00Z THIS EVENING WITH
ALL SNOW ACROSS SWRN NEB. DESPITE THIS THE RAP KEEPS ACCUMULATING
SNOW ACCUMULATIONS LIGHT...WEST OF HIGHWAY 61 BUT WITH HEAVY
ACCUMULATIONS OVER THE COLORADO PLAINS. THE FORECAST TODAY FOLLOWS A
BLEND OF THE RAP AND 4 BIAS CORRECTED GUIDANCE DATASETS FOR HIGHS IN
THE 40S.
THE BLEND OF 4 BIAS CORRECTED GUIDANCE DATASETS PRODUCES LOWS IN THE
30S TO NEAR 40 TONIGHT. IF THIS TEMPERATURE FORECAST IS CLOSE...THEN
SNOW SHOULD BECOME WIDESPREAD ACROSS THE CNTL AND WRN SANDHILLS.
NOTE THE RAP IS FORECASTING VSBY LESS THAN 1/4 MILE AT 00Z AND THIS
IS DISTURBING AS IT REPRESENTS HEAVY SNOW. IT MIGHT BE BEST TO
REVISIT THE RAP MODEL AFTER THE 12Z UPPER AIR DATA INGEST IS
COMPLETE AROUND 13Z OR 14Z.
A WINTER WEATHER ADVISORY IS IN PLACE FOR THE SANDHILLS TONIGHT AND
SATURDAY. SNOW IS UNDERWAY IN LIMON THIS MORNING AND SNOW LEVELS
ACROSS THE SANDHILLS SHOULD FALL TO AROUND 3500 FEET TONIGHT.
HEAVY RAIN IS FORECAST FOR TONIGHT FOR AREAS EAST OF HIGHWAY 83. THE
BLENDED SOLN PRODUCES AROUND 1.5 INCHES OF RAINFALL IN 12 HOURS
TONIGHT WHICH MAY PRODUCE MINOR FLOODING. THE DOWN-SCALED NAM AND TO
A LESSER EXTENT THE ARW AND NMM REFLECTIVITY PRODUCTS SHOW
CONVECTION JUST EAST OF THE FCST AREA TONIGHT. THE NAM12 INDICATES
ELEVATED CAPE ACROSS SCNTL NEB EAST OF THE FCST AREA ALSO. ALL OF
THIS CONVECTION WILL BE FEEDING NORTHWEST INTO A DEFORMATION ZONE
ACROSS THE SANDHILLS TONIGHT.
LASTLY...A FAIRLY WIDESPREAD SEVERE WEATHER EVENT IS EXPECTED ACROSS
THE MID SOUTH WHICH SHOULD MOMENTARILY BLOCK OR DEFLECT MOISTURE
TRANSPORT INTO THE STORM ACROSS NEB. THE MODELS TEND TO MIS-FORECAST
THIS FEATURE AND CONTINUE TO FORECAST HEAVY RAIN OR SNOW FARTHER
NORTH WHICH SOMETIMES DOES NOT MATERIALIZE. THUS THE PROSPECT OF
HEAVY RAIN AND SNOW ACROSS THE FCST AREA IS SOMEWHAT UNCERTAIN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 29 2016
MID RANGE...SATURDAY AND SUNDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION AS THE POTENT UPPER LOW SLOWLY
CROSSES THE CENTRAL PLAINS.
SATURDAY... LOWERED MAX TEMPS ANOTHER DEGREE OR SO AS GUIDANCE HAS
BEEN OVERSHOOTING TEMPS LATELY. CURRENT FORECAST HIGHS ARE NOW NEAR
40F WEST AND LOWER/MID 40S EAST... WHICH IS ABOUT 5 DEGREES BELOW
MAV/MET BUT SLIGHTLY ABOVE ECS. WENT AHEAD AND INTRODUCED ALL SNOW
FOR THE PANHANDLE AND FAR WESTERN SANDHILLS THROUGH 18Z. NAM AND GFS
FORECAST SOUNDINGS AGREE ON SATURATION IN THE DGZ THROUGHOUT THE
MORNING... INDICATING ICE INITIATION IN THE CLOUD LAYER. NAM KEEPS
VIRTUALLY THE ENTIRE TEMP PROFILE AT OR BELOW FREEZING AT KAIA AND
KOGA... WHICH SUGGESTS LITTLE TO NO MELTING. IN ADDITION...
APPRECIABLE LIFT EXISTS AS SHOWN BY NEGATIVE OMEGA IN SOUNDINGS...
ISENTROPIC UPGLIDE AT 295K AND 300K... AND NEARLY UPRIGHT AGEO
CIRCULATION IN CROSS SECTIONS OF THE SANDHILLS. THE H3 JET IS ALSO
NEARBY... PROVIDING EXTRA DIVERGENCE ALOFT. THE POTENTIAL FOR
MODERATE SNOW EXISTS... BUT THE QUESTION IS HOW MUCH SNOW ACTUALLY
ACCUMULATES DUE TO RELATIVELY WARM GROUND TEMPS. CONFIDENCE IS LOW
FOR HEAVY SNOW... OR AT LEAST HEAVY ENOUGH TO COMPENSATE AND PILE UP
ON NON GRASSY SURFACES. FARTHER EAST ALONG THE HWY 83 CORRIDOR...
TEMP PROFILES HUG THE FREEZING LINE FOR THE LOWEST 200HPA... RAISING
THE POSSIBILITY OF MELTING SNOW. GIVEN SLIGHTLY WARMER MIN TEMPS...
KEPT PTYPE AS RASN. ENOUGH LOW LEVEL WARMING SHOULD TAKE PLACE
AFTN/EVE TO SWITCH PRECIP TO ALL RAIN FOR THE ENTIRE CWA. FLIPPED
BACK TO RASN SAT NIGHT ACROSS THE WEST AND SNOW IN THE PANHANDLE.
MOISTURE CONTENT WILL BE LOWER AND THE FORCING WEAKER... SO
ACCUMULATING SNOW IS NOT AS BIG A CONCERN AS SAT AM.
SUNDAY... MADE LITTLE CHANGE TO MAX TEMPS AS WEAK WAA RESUMES.
HOWEVER... CONTINUED BKN/OVC CONDITIONS AND NORTH/NORTHEAST WINDS
WILL STILL LIMIT HIGHS TO THE LOWER 50S. CUT POPS BACK AS THE MID
LEVELS START TO DRY OUT. SOME LIFT AND RELATIVELY STEEP LAPSE RATES
STILL EXIST IN THE LOW LEVELS AND SOME WEAK FGEN FORCING AT H7
REMAINS... SO CANT ENTIRELY RULE OUT A SHOWER... MAINLY SOUTHERN AND
WESTERN PORTIONS OF THE CWA.
LONG RANGE...MONDAY THROUGH THURSDAY... A WEAK SHORTWAVE TRAVERSES
THE AREA MONDAY... BUT THE BEST MOISTURE IS ACROSS SOUTHWEST
NEBRASKA. SCHC POPS CONFINED GENERALLY ALONG/SOUTH OF I-80 AM/EARLY
PM. MIDWEEK... AN UPPER LEVEL RIDGE AND SURFACE HIGH PRESSURE
CONTROL THE PATTERN OVER THE ROCKIES AND PLAINS. SIGNIFICANT WARMING
IS DUE WITH DOWNSLOPE FLOW ON TUESDAY AND A THERMAL RIDGE
APPROACHING THE AREA WEDNESDAY. H85 TEMPS EXCEED 10C FOR WESTERN AND
CENTRAL NEB WED AND CLOSE TO 15C PANHANDLE. THE UPPER RIDGE AXIS IS
ON OUR DOORSTEP THURSDAY WHILE THE H85 RIDGE AXIS BISECTS THE
AREA... FLIPPING THE FLOW TO SOUTHERLY. GFS A LITTLE QUICKER AND
WARMER THAN EURO WITH THIS FEATURE... BUT HIGHS SHOULD HAVE NO
PROBLEM REACHING THE 70S ONCE AGAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 629 AM CDT FRI APR 29 2016
IFR/MVFR CIGS CONTINUE TODAY AND LOWER TO IFR/LIFR TONIGHT IN RAIN
AND HEAVY SNOW. RAIN SHOULD BEGIN ACROSS AREAS SOUTH OF I-80 THIS
MORNING AND MOVE NORTH OF THE INTERSTATE THIS AFTN. RAIN CHANGES
TO SNOW TONIGHT ALONG AND WEST OF HIGHWAY 83 WHERE LIFR WILL
BECOME WIDESPREAD. IFR/RAIN IS LIKELY EAST OF HIGHWAY 83.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM CDT /6 PM MDT/ THIS EVENING TO
7 PM CDT /6 PM MDT/ SATURDAY FOR NEZ004-022>024-035-036-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...SNIVELY
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
350 AM CDT FRI APR 29 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT FRI APR 29 2016
TODAY AND TONIGHT...THE RAP IS TRACKING THE POWERFUL UPPER LOW
ACROSS THE 4 CORNERS REGION AND BRINGING RAIN AND SNOW INTO SWRN NEB
BY LATE AFTERNOON. THIS IS CLOSE TO THE COOLER NAM SOLN. IN FACT THE
RAP SHOWS RAIN AND SNOW EAST OF HIGHWAY 83 AT 00Z THIS EVENING WITH
ALL SNOW ACROSS SWRN NEB. DESPITE THIS THE RAP KEEPS ACCUMULATING
SNOW ACCUMULATIONS LIGHT...WEST OF HIGHWAY 61 BUT WITH HEAVY
ACCUMULATIONS OVER THE COLORADO PLAINS. THE FORECAST TODAY FOLLOWS A
BLEND OF THE RAP AND 4 BIAS CORRECTED GUIDANCE DATASETS FOR HIGHS IN
THE 40S.
THE BLEND OF 4 BIAS CORRECTED GUIDANCE DATASETS PRODUCES LOWS IN THE
30S TO NEAR 40 TONIGHT. IF THIS TEMPERATURE FORECAST IS CLOSE...THEN
SNOW SHOULD BECOME WIDESPREAD ACROSS THE CNTL AND WRN SANDHILLS.
NOTE THE RAP IS FORECASTING VSBY LESS THAN 1/4 MILE AT 00Z AND THIS
IS DISTURBING AS IT REPRESENTS HEAVY SNOW. IT MIGHT BE BEST TO
REVISIT THE RAP MODEL AFTER THE 12Z UPPER AIR DATA INGEST IS
COMPLETE AROUND 13Z OR 14Z.
A WINTER WEATHER ADVISORY IS IN PLACE FOR THE SANDHILLS TONIGHT AND
SATURDAY. SNOW IS UNDERWAY IN LIMON THIS MORNING AND SNOW LEVELS
ACROSS THE SANDHILLS SHOULD FALL TO AROUND 3500 FEET TONIGHT.
HEAVY RAIN IS FORECAST FOR TONIGHT FOR AREAS EAST OF HIGHWAY 83. THE
BLENDED SOLN PRODUCES AROUND 1.5 INCHES OF RAINFALL IN 12 HOURS
TONIGHT WHICH MAY PRODUCE MINOR FLOODING. THE DOWN-SCALED NAM AND TO
A LESSER EXTENT THE ARW AND NMM REFLECTIVITY PRODUCTS SHOW
CONVECTION JUST EAST OF THE FCST AREA TONIGHT. THE NAM12 INDICATES
ELEVATED CAPE ACROSS SCNTL NEB EAST OF THE FCST AREA ALSO. ALL OF
THIS CONVECTION WILL BE FEEDING NORTHWEST INTO A DEFORMATION ZONE
ACROSS THE SANDHILLS TONIGHT.
LASTLY...A FAIRLY WIDESPREAD SEVERE WEATHER EVENT IS EXPECTED ACROSS
THE MID SOUTH WHICH SHOULD MOMENTARILY BLOCK OR DEFLECT MOISTURE
TRANSPORT INTO THE STORM ACROSS NEB. THE MODELS TEND TO MIS-FORECAST
THIS FEATURE AND CONTINUE TO FORECAST HEAVY RAIN OR SNOW FARTHER
NORTH WHICH SOMETIMES DOES NOT MATERIALIZE. THUS THE PROSPECT OF
HEAVY RAIN AND SNOW ACROSS THE FCST AREA IS SOMEWHAT UNCERTAIN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 29 2016
MID RANGE...SATURDAY AND SUNDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION AS THE POTENT UPPER LOW SLOWLY
CROSSES THE CENTRAL PLAINS.
SATURDAY... LOWERED MAX TEMPS ANOTHER DEGREE OR SO AS GUIDANCE HAS
BEEN OVERSHOOTING TEMPS LATELY. CURRENT FORECAST HIGHS ARE NOW NEAR
40F WEST AND LOWER/MID 40S EAST... WHICH IS ABOUT 5 DEGREES BELOW
MAV/MET BUT SLIGHTLY ABOVE ECS. WENT AHEAD AND INTRODUCED ALL SNOW
FOR THE PANHANDLE AND FAR WESTERN SANDHILLS THROUGH 18Z. NAM AND GFS
FORECAST SOUNDINGS AGREE ON SATURATION IN THE DGZ THROUGHOUT THE
MORNING... INDICATING ICE INITIATION IN THE CLOUD LAYER. NAM KEEPS
VIRTUALLY THE ENTIRE TEMP PROFILE AT OR BELOW FREEZING AT KAIA AND
KOGA... WHICH SUGGESTS LITTLE TO NO MELTING. IN ADDITION...
APPRECIABLE LIFT EXISTS AS SHOWN BY NEGATIVE OMEGA IN SOUNDINGS...
ISENTROPIC UPGLIDE AT 295K AND 300K... AND NEARLY UPRIGHT AGEO
CIRCULATION IN CROSS SECTIONS OF THE SANDHILLS. THE H3 JET IS ALSO
NEARBY... PROVIDING EXTRA DIVERGENCE ALOFT. THE POTENTIAL FOR
MODERATE SNOW EXISTS... BUT THE QUESTION IS HOW MUCH SNOW ACTUALLY
ACCUMULATES DUE TO RELATIVELY WARM GROUND TEMPS. CONFIDENCE IS LOW
FOR HEAVY SNOW... OR AT LEAST HEAVY ENOUGH TO COMPENSATE AND PILE UP
ON NON GRASSY SURFACES. FARTHER EAST ALONG THE HWY 83 CORRIDOR...
TEMP PROFILES HUG THE FREEZING LINE FOR THE LOWEST 200HPA... RAISING
THE POSSIBILITY OF MELTING SNOW. GIVEN SLIGHTLY WARMER MIN TEMPS...
KEPT PTYPE AS RASN. ENOUGH LOW LEVEL WARMING SHOULD TAKE PLACE
AFTN/EVE TO SWITCH PRECIP TO ALL RAIN FOR THE ENTIRE CWA. FLIPPED
BACK TO RASN SAT NIGHT ACROSS THE WEST AND SNOW IN THE PANHANDLE.
MOISTURE CONTENT WILL BE LOWER AND THE FORCING WEAKER... SO
ACCUMULATING SNOW IS NOT AS BIG A CONCERN AS SAT AM.
SUNDAY... MADE LITTLE CHANGE TO MAX TEMPS AS WEAK WAA RESUMES.
HOWEVER... CONTINUED BKN/OVC CONDITIONS AND NORTH/NORTHEAST WINDS
WILL STILL LIMIT HIGHS TO THE LOWER 50S. CUT POPS BACK AS THE MID
LEVELS START TO DRY OUT. SOME LIFT AND RELATIVELY STEEP LAPSE RATES
STILL EXIST IN THE LOW LEVELS AND SOME WEAK FGEN FORCING AT H7
REMAINS... SO CANT ENTIRELY RULE OUT A SHOWER... MAINLY SOUTHERN AND
WESTERN PORTIONS OF THE CWA.
LONG RANGE...MONDAY THROUGH THURSDAY... A WEAK SHORTWAVE TRAVERSES
THE AREA MONDAY... BUT THE BEST MOISTURE IS ACROSS SOUTHWEST
NEBRASKA. SCHC POPS CONFINED GENERALLY ALONG/SOUTH OF I-80 AM/EARLY
PM. MIDWEEK... AN UPPER LEVEL RIDGE AND SURFACE HIGH PRESSURE
CONTROL THE PATTERN OVER THE ROCKIES AND PLAINS. SIGNIFICANT WARMING
IS DUE WITH DOWNSLOPE FLOW ON TUESDAY AND A THERMAL RIDGE
APPROACHING THE AREA WEDNESDAY. H85 TEMPS EXCEED 10C FOR WESTERN AND
CENTRAL NEB WED AND CLOSE TO 15C PANHANDLE. THE UPPER RIDGE AXIS IS
ON OUR DOORSTEP THURSDAY WHILE THE H85 RIDGE AXIS BISECTS THE
AREA... FLIPPING THE FLOW TO SOUTHERLY. GFS A LITTLE QUICKER AND
WARMER THAN EURO WITH THIS FEATURE... BUT HIGHS SHOULD HAVE NO
PROBLEM REACHING THE 70S ONCE AGAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1133 PM CDT THU APR 28 2016
AN UPPER LEVEL LOW PRESSURE CENTER WILL APPROACH THE CENTRAL AND
SOUTHERN PLAINS FROM THE SOUTHERN ROCKIES OVER THE NEXT 24
HOURS. THIS FEATURE WILL BRING OCCASIONAL RAIN AND LOW CIGS TO
WESTERN AND NORTH CENTRAL NEBRASKA. FOR THE KLBF
TERMINAL...EXPECT MVFR CIGS TO DROP TO IFR CIGS BY DAYBREAK
FRIDAY. LIGHT RAIN WILL DEVELOP BY MID MORNING AND WILL PERSIST
INTO FRIDAY EVENING. CIGS WILL BE BELOW 1000 FT AGL AND VISBYS
DOWN TO 4SM ARE POSSIBLE AS WELL. FOR THE KVTN TERMINAL...EXPECT
IFR CIGS TO DEVELOP WITH REDUCED VISIBILITIES POSSIBLE OVERNIGHT.
CIGS AND VISBYS WILL IMPROVE FRIDAY MORNING...BECOMING MVFR BY MID
AFTERNOON. CIGS WILL FALL BELOW IFR LEVELS LATE FRIDAY AFTERNOON
AND REMAIN THERE THROUGH FRIDAY EVENING. LIGHT RAIN WILL DEVELOP
AFTER 22Z FRIDAY AFTERNOON AND IS EXPECTED TO PERSIST THROUGH
FRIDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM CDT /6 PM MDT/ THIS EVENING TO
7 PM CDT /6 PM MDT/ SATURDAY FOR NEZ004-022>024-035-036-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...SNIVELY
AVIATION...BUTTLER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 AM EDT FRI APR 29 2016
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA EARLY FRIDAY MORNING.
A COUPLE OF DRY FRONTS WILL MOVE ACROSS THE REGION THIS WEEKEND.
UNSETTLED CONDITIONS WILL REAPPEAR LATE IN THE WEEKEND AND
CONTINUE THROUGH THE MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 900 PM THURSDAY...THE LAST OF THE SHOWERS AND THUNDERSTORMS
WERE MOVING ACROSS CENTRAL NORTH CAROLINA. A NEW BATCH OF
CONVECTION HAS FLARED UP ACROSS THE PIEDMONT AS THE SEABREEZE AND
AN OUTFLOW BOUNDARY CONVERGED. THESE ARE THE SHOWERS AND
THUNDERSTORMS THAT THE HRRR MODEL HAS BEEN FORECASTING TO BRUSH
THE NORTHERN TIER OF THE FORECAST AREA.
A TROUGH WILL MOVE ACROSS THE FORECAST AREA LATE THIS EVE AND
OVERNIGHT AND THIS SHOULD END THE RISK FOR CONVECTION. A COLD
FRONT WILL FOLLOW FRI MORNING WITH DEWPOINTS DROPPING LATE MORNING
AND AFTERNOON...FROM W TO E.
WILL MAINTAIN SMALL POPS FOR SOUTHEAST NORTH CAROLINA AND FOR THE
NORTHERN PEE DEE THROUGH NORTHERN GRAND STRAND COMMUNITIES OF
SOUTH CAROLINA. WILL CONTINUE TO MENTION ISOLATED SHOWERS AND
THUNDERSTORMS...BUT SEVERE WEATHER IS NOT EXPECTED. WILL LOWER
POPS BELOW THRESHOLD...FROM W TO E OVERNIGHT. MODEL SOUNDINGS ARE
SUPPORTIVE OF PATCHY FOG AS WINDS EVEN THROUGH THE BOUNDARY LAYER
LIGHTEN UP OVERNIGHT. LOCATIONS WHERE RAIN DID FALL TODAY WILL BE
MOST SUSCEPTIBLE TO PATCHY FOG.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS OF 315 PM THURSDAY...WITH THE WEAK SURFACE FRONT OFF THE COAST
FRIDAY MORNING...LIGHT OFFSHORE WINDS SHOULD BRING SLIGHTLY DRIER
AIR INTO THE AREA. WITH PLENTY OF SUNSHINE TEMPERATURES SHOULD SOAR
INTO THE UPPER 80S FOR MOST INLAND AREAS...POSSIBLY APPROACHING 90
DEGREES IN FLORENCE! THE SEABREEZE WILL BE DELAYED BY THE OFFSHORE
WIND AND THIS SHOULD ALLOW THE BEACHES TO WARM TO 80 DEGREES OR
BETTER BEFORE THE SEABREEZE FINALLY FORMS AROUND 2-3 PM.
WINDS WILL BE QUICK TO VEER EASTERLY FRIDAY NIGHT AS THE HIGH BEHIND
THIS FRONT DOES NOT BUILD APPRECIABLY SOUTHWARD. THIS VEERING LOW-
LEVEL WIND SHOULD CONTINUE INTO SATURDAY...LEADING TO GRADUALLY
INCREASING LOW LEVEL MOISTURE THROUGH THE DAY. IT`S WORTH NOTING THE
12Z NAM IS MUCH MORE MOIST (AND CLOUDIER) AND THEREFORE MUCH COOLER
WITH TEMPERATURES ON SATURDAY COMPARED TO THE GFS. GIVEN THE COOL
EAST-SOUTHEAST WIND PREDICTED ON BOTH MODELS THE 12Z GFS HIGHS LOOK
TOO WARM REGARDLESS OF WHAT LOW-LEVEL MOISTURE TURNS OUT TO BE.
A LARGE UPPER LEVEL LOW EJECTING OUT OF THE ROCKIES INTO THE PLAINS
STATES WILL ALSO BEGIN TO SPREAD MID AND HIGH LEVEL MOISTURE
EASTWARD ACROSS THE GULF COAST AND EVENTUALLY THE CAROLINAS BY
SATURDAY. AS MOISTURE DEEPENS THIS COULD LEAD TO SHOWERS DEVELOPING
AS EARLY AS LATE SATURDAY AFTERNOON WEST OF I-95...PERHAPS BECOMING
A BIT MORE NUMEROUS SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 315 PM THURSDAY...HIGHLY AMPLIFIED PATTERN WILL KEEP AT LEAST SOME
SEMBLANCE OF POPS IN THE FORECAST THROUGH THE PERIOD. WPC CONTINUES
TO PREFER A SOLUTION WITH A GOOD DEAL OF THE ECMWF OPERATIONAL AND
ENSEMBLES MIXED IN. THE GFS IS GENERALLY DRIER.
A BROAD SOUTHWEST FLOW WILL DEVELOP WITH SEVERAL EMBEDDED SHORTWAVES
FROM SUNDAY THROUGH WEDNESDAY. AT THE SURFACE A FRONT WILL SLOWLY
MOVE FROM THE APPALACHIANS TO JUST OFFSHORE THROUGH WEDNESDAY. BY
THURSDAY A DEEPER MID LEVEL TROUGH SHOULD GIVE SURFACE FEATURES MORE
PUSH. THE HIGHEST POPS OCCUR SUNDAY WITH AN INITIAL WAVE AND TUESDAY
WHEN A SECOND WAVE MOVES BY. CERTAINLY NO EXTENDED PERIODS OF HEAVY
RAIN ARE EXPECTED BUT WPC QPF FOR DAYS 4-7 ARE NEAR TWO INCHES.
TEMPERATURE FORECAST HAS TRENDED DOWN A LITTLE FROM PREVIOUS
GUIDANCE BUT STILL OVERALL AVERAGES ARE ABOVE NORMAL.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...MVFR CONDITIONS POSSIBLE DUE TO REDUCED VSBY FROM FOG
THRU 13Z...ESPECIALLY THE TERMINALS THAT RECEIVED RAINFALL.
OTHERWISE...EXPECT VFR CONDITIONS.
SFC LOW LOCATED OVER CENTRAL NC ATTM...WILL ACCELERATE TO OFF THE
OUTER BANKS BY DAYBREAK. THE CURRENT SHOWER AND TSTORM ACTIVITY TO
REMAIN NORTH OF THE AREA TERMINALS AS IT PROGRESSES ESE TOWARD AND
OFF THE NC COAST PRIOR TO DAYBREAK. THE ASSOCIATED COLD FRONT
WILL PUSH ACROSS THE AREA TERMINALS PRIOR TO DAYBREAK FOR THE FLO
AND LBT TERMINALS...AND ACROSS THE COASTAL TERMINALS AND OFF THE
COAST AROUND OR JUST AFTER DAYBREAK. DRIER AIR IN THE MID AND
UPPER LEVELS WILL OVERSPREAD THE FA THIS MORNING...AND IN EARNST
THRUOUT THE DAY TODAY. ANY CEILINGS OR FOG DURING THE PRE-DAWN
HRS WILL SCOUR OUT QUICKLY AFTER DAYBREAK. AFTER THE CFP...WINDS
WILL VEER TO THE NW AT 10 KT OR LESS THIS MORNING. THE SFC
PRESSURE PATTERN AND RELAXING GRADIENT THIS AFTN AND TONIGHT TO
YIELD A VARIABLE WIND LESS THAN 5 KT AFTER SUNSET. THIS WILL ALLOW
AN ACTIVE SEA BREEZE...WINDS BECOMING 140-170 AROUND 10 KT AT THE
COASTAL TERMS...THIS AFTN AND EVENING AS WINDS SFC-850MB DROPS TO
LESS THAN 15 KT. ENOUGH MOISTURE IN THE LOWER LEVELS AND THE DAYS
INSOLATION COULD PRODUCE FEW/SCT CU...OTHERWISE SKC TO PREVAIL
INTO THRU THIS EVENING. DO NOT EXPECT MUCH VERTICAL DEVELOPMENT
WITH THE CU DUE TO SUBSIDENCE ALOFT.
EXTENDED OUTLOOK...MVFR/IFR POSSIBLE FROM CONVECTION SUNDAY INTO
THROUGH TUESDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 900 PM THURSDAY...A TROUGH WILL MOVE ACROSS THE WATERS
OVERNIGHT. A COLD FRONT WILL FOLLOW FRI MORNING. SW WINDS WILL
VEER TO WSW NEAR DAYBREAK AND THEN NW FRI MORNING. SUSTAINED WIND
SPEEDS OF 10 TO 15 KT WILL DECREASE TO 10 KT NEAR DAYBREAK.
STRONGER WINDS ARE POSSIBLE IN AND NEAR CONVECTION. SEAS WILL BE 3
FT.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 315 PM THURSDAY...LIGHT OFFSHORE WINDS ARE EXPECTED IN THE
WAKE OF A COLD FRONT FRIDAY MORNING. INTENSE SOLAR HEATING INLAND
SHOULD HELP DEVELOP AN AFTERNOON SEABREEZE WITH NEARSHORE WINDS
TURNING ONSHORE FRIDAY AFTERNOON.
THE HIGH BEHIND THE WEAK COLD FRONT DOESN`T DIG SOUTH INTO THE
CAROLINAS...ALLOWING WINDS TO QUICKLY VEER EASTERLY FRIDAY NIGHT AND
SOUTHEASTERLY ON SATURDAY. SPEEDS SHOULD REMAIN 15 KT OR LESS WITH
SEAS 3 FT OR LESS.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 315 PM THURSDAY...A MODEST ONSHORE FLOW WILL INITIALLY BE IN
PLACE SUNDAY FROM THE SOUTHEAST. SPEEDS WILL BE TEN KNOTS OR LESS.
BY MONDAY A FRONT MOVING CLOSER INCREASES THE GRADIENT AND BACKS
THE WINDS FROM THE SOUTHWEST A BIT. SPEEDS INCREASE TO 10-15 KT.
THE FRONT EASES ACROSS EARLY TUESDAY WITH WINDS BECOMING ESSENTIALLY
LIGHT AND VARIABLE. SIGNIFICANT SEAS WILL BE 2-4 FEET. THERE COULD
BE A FEW FIVE FOOTERS MIXED IN BRIEFLY LATE MONDAY AS WELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RJD
NEAR TERM...RJD
SHORT TERM...TRA
LONG TERM...SHK
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1159 AM CDT FRI APR 29 2016
.UPDATE...
ISSUED AT 1155 AM CDT FRI APR 29 2016
WIDELY SCATTERED SHOWERS CONTINUE SOUTHWEST IN THE VICINITY OF A
WEAK H500 TROUGH RIDING UP THE RIDGE OVER THE NORTH CENTRAL US.
THESE SHOWERS WILL LIKELY PERSIST INTO THE AFTERNOON ACROSS THE
SOUTHWEST.
UPDATE ISSUED AT 831 AM CDT FRI APR 29 2016
ADDED A SMALL CHANCE FOR SHOWERS ACROSS FAR SOUTHWEST NORTH DAKOTA
WHERE BOWMAN RADAR SHOWS SOME LIGHT RADAR RETURNS. OTHERWISE
FORECAST TRENDING OK.
UPDATE ISSUED AT 622 AM CDT FRI APR 29 2016
HIGH PRESSURE REMAINS OVER THE FORECAST AREA THIS MORNING. SKIES
HAVE CLEARED SOME...ESPECIALLY OVER THE SOUTH CENTRAL AND HAVE
LOWERED SKY COVER HERE THIS MORNING. POPULATED LATEST SENSIBLE
WEATHER OBSERVATIONS AND BLENDED TEMPERATURES INTO OUR CURRENT
MID-MORNING FORECAST TEMPERATURES. OTHERWISE NO SIGNIFICANT
CHANGES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT FRI APR 29 2016
RATHER UNEVENTFUL SHORT TERM PERIOD WITH THE ONLY SIGNIFICANT
ISSUE BEING MINIMAL FIRE WEATHER ISSUES DUE TO LOW AFTERNOON
HUMIDITIES ACROSS THE NORTH.
THE HIGH OVER LOW BLOCKING PATTERN WILL REMAIN IN PLACE OVER THE
NORTHERN PLAINS THROUGH THE SHORT TERM PERIOD MEANING NO
SIGNIFICANT SYNOPTIC SYSTEMS TO INFLUENCE OUR WEATHER.
CURRENTLY...SURFACE AND UPPER LEVEL HIGH PRESSURE IS SITUATED
OVER SOUTHERN CANADA BRINGING COOL AND DRY CONDITIONS TO THE
FORECAST AREA. WE WOULD PROBABLY BE QUITE A BIT COOLER IF THE MID
LEVEL MOISTURE LINGERING OVER THE AREA FOR THE PAST FEW DAYS WERE
A LITTLE LESS ROBUST. CURRENT TEMPERATURES ARE HOLDING PRETTY
STEADY IN THE 30S BUT SURFACE DEWPOINTS ARE RANGING FROM THE TEENS
TO LOWER 20S OVER THE NORTH AND EAST. WE MAY STILL DROP INTO THE
20S ACROSS THE NORTHEAST CWA...BUT THE FAR SOUTHWEST WITH
DEWPOINTS STEADY IN THE MID 30S WILL LIKELY NOT DROP AS LOW AS
PREVIOUSLY FORECAST.
FOR TODAY AND TONIGHT...UTILIZED A PERSISTENCE FORECAST...BUT
ALLOWED FOR SOME WARMING AS 85H TEMPERATURES DO WARM A LITTLE AND
OUR MID LEVEL MOISTURE GETS WRUNG OUT WITH THE BUILDING UPPER HIGH
TO OUR NORTH. ONE SIGNIFICANT CHANGE FROM THE DEFAULT SHORT TERM
GUIDANCE WAS TO LOWER DEWPOINTS ACROSS THE NORTH. OUR
EXPERIMENTAL HRRR WAS NOT AVAILABLE THIS MORNING BUT THE
OPERATIONAL HRRR LOOKED REASONABLE WITH 15-20 DEGREE DEWPOINTS
ACROSS THE NORTHERN TIER COUNTIES THIS AFTERNOON...RESULTING IN
MINIMUM HUMIDITIES OF 15 TO 20 PERCENT ACROSS THE FAR NORTHERN
TIER COUNTIES AND 20 TO 25 PERCENT RH FOR THE NEXT TIER. WINDS
THIS AFTERNOON ARE NOT EXPECTED TO BE STRONG AND UTILIZING SOME OF
THE HIGHER GUIDANCE WINDS WE ARE STILL NOT MORE THAN 10 TO 15 MPH
SUSTAINED TODAY. THUS ANY FIRE WEATHER ISSUES SHOULD BE MINIMAL.
WILL PASS THIS ALONG TO THE NEXT SHIFT TO MONITOR BUT DO NOT
ANTICIPATE ANY FIRE WEATHER HAZARDS.
ANOTHER QUIET NIGHT WITH MORE CLEARING SHOULD RESULT IN ANOTHER
COOL NIGHT WITH LOW IN THE 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 326 AM CDT FRI APR 29 2016
QUIET WEATHER CONTINUES INTO THE LONG TERM PERIOD. AGAIN UTILIZED
PERSISTENCE INTO THE WEEKEND WITH OUR BLOCKING PATTERN AND
GENERALLY RAISED TEMPERATURES JUST A FEW DEGREES EACH DAY SATURDAY
AND SUNDAY. THE EXCEPTION WAS THE FAR SOUTHWEST...WHICH SHOULD
BEGIN TO RISE A LITTLE QUICKER AS WE LOSE ANY REMAINING SNOW.
AS WE HEAD INTO NEXT WEEK...THE GFS/ECMWF BOTH ADVERTISE A WESTERN
U.S. RIDGE WITH TROUGHING OFF THE PACIFIC COAST AND OVER THE
EASTERN U.S. WE WILL BE RIGHT ON THE TRANSITION OF THE
RIDGE/TROUGH REGIME AND AFTER A MILD BEGINNING OF THE WORK WEEK WE
COULD SEE A LITTLE SETBACK IN TEMPERATURES...ESPECIALLY OVER THE
EASTERN CWA DUE TO A BACKDOOR COLD FRONT ASSOCIATED WITH A CLIPPER
DROPPING INTO THE DEVELOPING EAST COAST TROUGH. WE ARE TALKING
ONLY A FEW DEGREES HERE AND THE FRONT WOULD BE DRY. REALLY THE
ONLY HINT OF ANY PRECIPITATION THROUGH THE WEEK IS WITH A LEADING
WAVE DROPPING DOWN THE BUILDING UPPER RIDGE ON MONDAY. THE ECMWF
SHOWS THIS WAVE DROPPING FARTHER WEST ACROSS NORTH DAKOTA AND
COULD RESULT IN A SHOWER OR TWO. THE GFS TAKES IT MUCH FARTHER
EAST AND IS DRY ACROSS THE CWA. RIGHT NOW A MODEL BLEND SOLUTION
DOES NOT CREATE ENOUGH SUPPORT FOR A MENTION OF SHOWERS. THEN LATE
IN THE WORK WEEK THE UPPER RIDGE BEGINS TO BREAK DOWN AND MODELS
WANT TO BRING A LITTLE QPF INTO THE WESTERN CWA FRIDAY NIGHT.
WOULD NOT BE SURPRISED IF THIS DOES NOT COME TO FRUITION GIVEN THE
DRY ATMOSPHERE AND RIDGING STILL HOLDING ON OVER EASTERN MONTANA
LATE IN THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1155 AM CDT FRI APR 29 2016
LARGE AND PERSISTENT SURFACE HIGH PRESSURE EXTENDS FROM MANITOBA
SOUTH AND WEST ACROSS THE NORTHERN PLAINS FRIDAY MORNING. VFR
EXPECTED ACROSS ALL TAF SITES THROUGH THE 18Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
832 AM CDT FRI APR 29 2016
.UPDATE...
ISSUED AT 831 AM CDT FRI APR 29 2016
ADDED A SMALL CHANCE FOR SHOWERS ACROSS FAR SOUTHWEST NORTH DAKOTA
WHERE BOWMAN RADAR SHOWS SOME LIGHT RADAR RETURNS. OTHERWISE
FORECAST TRENDING OK.
UPDATE ISSUED AT 622 AM CDT FRI APR 29 2016
HIGH PRESSURE REMAINS OVER THE FORECAST AREA THIS MORNING. SKIES
HAVE CLEARED SOME...ESPECIALLY OVER THE SOUTH CENTRAL AND HAVE
LOWERED SKY COVER HERE THIS MORNING. POPULATED LATEST SENSIBLE
WEATHER OBSERVATIONS AND BLENDED TEMPERATURES INTO OUR CURRENT
MID-MORNING FORECAST TEMPERATURES. OTHERWISE NO SIGNIFICANT
CHANGES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT FRI APR 29 2016
RATHER UNEVENTFUL SHORT TERM PERIOD WITH THE ONLY SIGNIFICANT
ISSUE BEING MINIMAL FIRE WEATHER ISSUES DUE TO LOW AFTERNOON
HUMIDITIES ACROSS THE NORTH.
THE HIGH OVER LOW BLOCKING PATTERN WILL REMAIN IN PLACE OVER THE
NORTHERN PLAINS THROUGH THE SHORT TERM PERIOD MEANING NO
SIGNIFICANT SYNOPTIC SYSTEMS TO INFLUENCE OUR WEATHER.
CURRENTLY...SURFACE AND UPPER LEVEL HIGH PRESSURE IS SITUATED
OVER SOUTHERN CANADA BRINGING COOL AND DRY CONDITIONS TO THE
FORECAST AREA. WE WOULD PROBABLY BE QUITE A BIT COOLER IF THE MID
LEVEL MOISTURE LINGERING OVER THE AREA FOR THE PAST FEW DAYS WERE
A LITTLE LESS ROBUST. CURRENT TEMPERATURES ARE HOLDING PRETTY
STEADY IN THE 30S BUT SURFACE DEWPOINTS ARE RANGING FROM THE TEENS
TO LOWER 20S OVER THE NORTH AND EAST. WE MAY STILL DROP INTO THE
20S ACROSS THE NORTHEAST CWA...BUT THE FAR SOUTHWEST WITH
DEWPOINTS STEADY IN THE MID 30S WILL LIKELY NOT DROP AS LOW AS
PREVIOUSLY FORECAST.
FOR TODAY AND TONIGHT...UTILIZED A PERSISTENCE FORECAST...BUT
ALLOWED FOR SOME WARMING AS 85H TEMPERATURES DO WARM A LITTLE AND
OUR MID LEVEL MOISTURE GETS WRUNG OUT WITH THE BUILDING UPPER HIGH
TO OUR NORTH. ONE SIGNIFICANT CHANGE FROM THE DEFAULT SHORT TERM
GUIDANCE WAS TO LOWER DEWPOINTS ACROSS THE NORTH. OUR
EXPERIMENTAL HRRR WAS NOT AVAILABLE THIS MORNING BUT THE
OPERATIONAL HRRR LOOKED REASONABLE WITH 15-20 DEGREE DEWPOINTS
ACROSS THE NORTHERN TIER COUNTIES THIS AFTERNOON...RESULTING IN
MINIMUM HUMIDITIES OF 15 TO 20 PERCENT ACROSS THE FAR NORTHERN
TIER COUNTIES AND 20 TO 25 PERCENT RH FOR THE NEXT TIER. WINDS
THIS AFTERNOON ARE NOT EXPECTED TO BE STRONG AND UTILIZING SOME OF
THE HIGHER GUIDANCE WINDS WE ARE STILL NOT MORE THAN 10 TO 15 MPH
SUSTAINED TODAY. THUS ANY FIRE WEATHER ISSUES SHOULD BE MINIMAL.
WILL PASS THIS ALONG TO THE NEXT SHIFT TO MONITOR BUT DO NOT
ANTICIPATE ANY FIRE WEATHER HAZARDS.
ANOTHER QUIET NIGHT WITH MORE CLEARING SHOULD RESULT IN ANOTHER
COOL NIGHT WITH LOW IN THE 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 326 AM CDT FRI APR 29 2016
QUIET WEATHER CONTINUES INTO THE LONG TERM PERIOD. AGAIN UTILIZED
PERSISTENCE INTO THE WEEKEND WITH OUR BLOCKING PATTERN AND
GENERALLY RAISED TEMPERATURES JUST A FEW DEGREES EACH DAY SATURDAY
AND SUNDAY. THE EXCEPTION WAS THE FAR SOUTHWEST...WHICH SHOULD
BEGIN TO RISE A LITTLE QUICKER AS WE LOSE ANY REMAINING SNOW.
AS WE HEAD INTO NEXT WEEK...THE GFS/ECMWF BOTH ADVERTISE A WESTERN
U.S. RIDGE WITH TROUGHING OFF THE PACIFIC COAST AND OVER THE
EASTERN U.S. WE WILL BE RIGHT ON THE TRANSITION OF THE
RIDGE/TROUGH REGIME AND AFTER A MILD BEGINNING OF THE WORK WEEK WE
COULD SEE A LITTLE SETBACK IN TEMPERATURES...ESPECIALLY OVER THE
EASTERN CWA DUE TO A BACKDOOR COLD FRONT ASSOCIATED WITH A CLIPPER
DROPPING INTO THE DEVELOPING EAST COAST TROUGH. WE ARE TALKING
ONLY A FEW DEGREES HERE AND THE FRONT WOULD BE DRY. REALLY THE
ONLY HINT OF ANY PRECIPITATION THROUGH THE WEEK IS WITH A LEADING
WAVE DROPPING DOWN THE BUILDING UPPER RIDGE ON MONDAY. THE ECMWF
SHOWS THIS WAVE DROPPING FARTHER WEST ACROSS NORTH DAKOTA AND
COULD RESULT IN A SHOWER OR TWO. THE GFS TAKES IT MUCH FARTHER
EAST AND IS DRY ACROSS THE CWA. RIGHT NOW A MODEL BLEND SOLUTION
DOES NOT CREATE ENOUGH SUPPORT FOR A MENTION OF SHOWERS. THEN LATE
IN THE WORK WEEK THE UPPER RIDGE BEGINS TO BREAK DOWN AND MODELS
WANT TO BRING A LITTLE QPF INTO THE WESTERN CWA FRIDAY NIGHT.
WOULD NOT BE SURPRISED IF THIS DOES NOT COME TO FRUITION GIVEN THE
DRY ATMOSPHERE AND RIDGING STILL HOLDING ON OVER EASTERN MONTANA
LATE IN THE WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 622 AM CDT FRI APR 29 2016
VFR CIGS/VSBYS THROUGH THE PERIOD. SCT/BKN MID LEVEL CLOUDS ALONG
WITH NORTHEAST TO EAST WINDS AROUND 10KT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
627 AM CDT FRI APR 29 2016
.UPDATE...
ISSUED AT 622 AM CDT FRI APR 29 2016
HIGH PRESSURE REMAINS OVER THE FORECAST AREA THIS MORNING. SKIES
HAVE CLEARED SOME...ESPECIALLY OVER THE SOUTH CENTRAL AND HAVE
LOWERED SKY COVER HERE THIS MORNING. POPULATED LATEST SENSIBLE
WEATHER OBSERVATIONS AND BLENDED TEMPERATURES INTO OUR CURRENT
MID-MORNING FORECAST TEMPERATURES. OTHERWISE NO SIGNIFICANT
CHANGES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT FRI APR 29 2016
RATHER UNEVENTFUL SHORT TERM PERIOD WITH THE ONLY SIGNIFICANT
ISSUE BEING MINIMAL FIRE WEATHER ISSUES DUE TO LOW AFTERNOON
HUMIDITIES ACROSS THE NORTH.
THE HIGH OVER LOW BLOCKING PATTERN WILL REMAIN IN PLACE OVER THE
NORTHERN PLAINS THROUGH THE SHORT TERM PERIOD MEANING NO
SIGNIFICANT SYNOPTIC SYSTEMS TO INFLUENCE OUR WEATHER.
CURRENTLY...SURFACE AND UPPER LEVEL HIGH PRESSURE IS SITUATED
OVER SOUTHERN CANADA BRINGING COOL AND DRY CONDITIONS TO THE
FORECAST AREA. WE WOULD PROBABLY BE QUITE A BIT COOLER IF THE MID
LEVEL MOISTURE LINGERING OVER THE AREA FOR THE PAST FEW DAYS WERE
A LITTLE LESS ROBUST. CURRENT TEMPERATURES ARE HOLDING PRETTY
STEADY IN THE 30S BUT SURFACE DEWPOINTS ARE RANGING FROM THE TEENS
TO LOWER 20S OVER THE NORTH AND EAST. WE MAY STILL DROP INTO THE
20S ACROSS THE NORTHEAST CWA...BUT THE FAR SOUTHWEST WITH
DEWPOINTS STEADY IN THE MID 30S WILL LIKELY NOT DROP AS LOW AS
PREVIOUSLY FORECAST.
FOR TODAY AND TONIGHT...UTILIZED A PERSISTENCE FORECAST...BUT
ALLOWED FOR SOME WARMING AS 85H TEMPERATURES DO WARM A LITTLE AND
OUR MID LEVEL MOISTURE GETS WRUNG OUT WITH THE BUILDING UPPER HIGH
TO OUR NORTH. ONE SIGNIFICANT CHANGE FROM THE DEFAULT SHORT TERM
GUIDANCE WAS TO LOWER DEWPOINTS ACROSS THE NORTH. OUR
EXPERIMENTAL HRRR WAS NOT AVAILABLE THIS MORNING BUT THE
OPERATIONAL HRRR LOOKED REASONABLE WITH 15-20 DEGREE DEWPOINTS
ACROSS THE NORTHERN TIER COUNTIES THIS AFTERNOON...RESULTING IN
MINIMUM HUMIDITIES OF 15 TO 20 PERCENT ACROSS THE FAR NORTHERN
TIER COUNTIES AND 20 TO 25 PERCENT RH FOR THE NEXT TIER. WINDS
THIS AFTERNOON ARE NOT EXPECTED TO BE STRONG AND UTILIZING SOME OF
THE HIGHER GUIDANCE WINDS WE ARE STILL NOT MORE THAN 10 TO 15 MPH
SUSTAINED TODAY. THUS ANY FIRE WEATHER ISSUES SHOULD BE MINIMAL.
WILL PASS THIS ALONG TO THE NEXT SHIFT TO MONITOR BUT DO NOT
ANTICIPATE ANY FIRE WEATHER HAZARDS.
ANOTHER QUIET NIGHT WITH MORE CLEARING SHOULD RESULT IN ANOTHER
COOL NIGHT WITH LOW IN THE 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 326 AM CDT FRI APR 29 2016
QUIET WEATHER CONTINUES INTO THE LONG TERM PERIOD. AGAIN UTILIZED
PERSISTENCE INTO THE WEEKEND WITH OUR BLOCKING PATTERN AND
GENERALLY RAISED TEMPERATURES JUST A FEW DEGREES EACH DAY SATURDAY
AND SUNDAY. THE EXCEPTION WAS THE FAR SOUTHWEST...WHICH SHOULD
BEGIN TO RISE A LITTLE QUICKER AS WE LOSE ANY REMAINING SNOW.
AS WE HEAD INTO NEXT WEEK...THE GFS/ECMWF BOTH ADVERTISE A WESTERN
U.S. RIDGE WITH TROUGHING OFF THE PACIFIC COAST AND OVER THE
EASTERN U.S. WE WILL BE RIGHT ON THE TRANSITION OF THE
RIDGE/TROUGH REGIME AND AFTER A MILD BEGINNING OF THE WORK WEEK WE
COULD SEE A LITTLE SETBACK IN TEMPERATURES...ESPECIALLY OVER THE
EASTERN CWA DUE TO A BACKDOOR COLD FRONT ASSOCIATED WITH A CLIPPER
DROPPING INTO THE DEVELOPING EAST COAST TROUGH. WE ARE TALKING
ONLY A FEW DEGREES HERE AND THE FRONT WOULD BE DRY. REALLY THE
ONLY HINT OF ANY PRECIPITATION THROUGH THE WEEK IS WITH A LEADING
WAVE DROPPING DOWN THE BUILDING UPPER RIDGE ON MONDAY. THE ECMWF
SHOWS THIS WAVE DROPPING FARTHER WEST ACROSS NORTH DAKOTA AND
COULD RESULT IN A SHOWER OR TWO. THE GFS TAKES IT MUCH FARTHER
EAST AND IS DRY ACROSS THE CWA. RIGHT NOW A MODEL BLEND SOLUTION
DOES NOT CREATE ENOUGH SUPPORT FOR A MENTION OF SHOWERS. THEN LATE
IN THE WORK WEEK THE UPPER RIDGE BEGINS TO BREAK DOWN AND MODELS
WANT TO BRING A LITTLE QPF INTO THE WESTERN CWA FRIDAY NIGHT.
WOULD NOT BE SURPRISED IF THIS DOES NOT COME TO FRUITION GIVEN THE
DRY ATMOSPHERE AND RIDGING STILL HOLDING ON OVER EASTERN MONTANA
LATE IN THE WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 622 AM CDT FRI APR 29 2016
VFR CIGS/VSBYS THROUGH THE PERIOD. SCT/BKN MID LEVEL CLOUDS ALONG
WITH NORTHEAST TO EAST WINDS AROUND 10KT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
401 AM CDT FRI APR 29 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT FRI APR 29 2016
RATHER UNEVENTFUL SHORT TERM PERIOD WITH THE ONLY SIGNIFICANT
ISSUE BEING MINIMAL FIRE WEATHER ISSUES DUE TO LOW AFTERNOON
HUMIDITIES ACROSS THE NORTH.
THE HIGH OVER LOW BLOCKING PATTERN WILL REMAIN IN PLACE OVER THE
NORTHERN PLAINS THROUGH THE SHORT TERM PERIOD MEANING NO
SIGNIFICANT SYNOPTIC SYSTEMS TO INFLUENCE OUR WEATHER.
CURRENTLY...SURFACE AND UPPER LEVEL HIGH PRESSURE IS SITUATED
OVER SOUTHERN CANADA BRINGING COOL AND DRY CONDITIONS TO THE
FORECAST AREA. WE WOULD PROBABLY BE QUITE A BIT COOLER IF THE MID
LEVEL MOISTURE LINGERING OVER THE AREA FOR THE PAST FEW DAYS WERE
A LITTLE LESS ROBUST. CURRENT TEMPERATURES ARE HOLDING PRETTY
STEADY IN THE 30S BUT SURFACE DEWPOINTS ARE RANGING FROM THE TEENS
TO LOWER 20S OVER THE NORTH AND EAST. WE MAY STILL DROP INTO THE
20S ACROSS THE NORTHEAST CWA...BUT THE FAR SOUTHWEST WITH
DEWPOINTS STEADY IN THE MID 30S WILL LIKELY NOT DROP AS LOW AS
PREVIOUSLY FORECAST.
FOR TODAY AND TONIGHT...UTILIZED A PERSISTENCE FORECAST...BUT
ALLOWED FOR SOME WARMING AS 85H TEMPERATURES DO WARM A LITTLE AND
OUR MID LEVEL MOISTURE GETS WRUNG OUT WITH THE BUILDING UPPER HIGH
TO OUR NORTH. ONE SIGNIFICANT CHANGE FROM THE DEFAULT SHORT TERM
GUIDANCE WAS TO LOWER DEWPOINTS ACROSS THE NORTH. OUR
EXPERIMENTAL HRRR WAS NOT AVAILABLE THIS MORNING BUT THE
OPERATIONAL HRRR LOOKED REASONABLE WITH 15-20 DEGREE DEWPOINTS
ACROSS THE NORTHERN TIER COUNTIES THIS AFTERNOON...RESULTING IN
MINIMUM HUMIDITIES OF 15 TO 20 PERCENT ACROSS THE FAR NORTHERN
TIER COUNTIES AND 20 TO 25 PERCENT RH FOR THE NEXT TIER. WINDS
THIS AFTERNOON ARE NOT EXPECTED TO BE STRONG AND UTILIZING SOME OF
THE HIGHER GUIDANCE WINDS WE ARE STILL NOT MORE THAN 10 TO 15 MPH
SUSTAINED TODAY. THUS ANY FIRE WEATHER ISSUES SHOULD BE MINIMAL.
WILL PASS THIS ALONG TO THE NEXT SHIFT TO MONITOR BUT DO NOT
ANTICIPATE ANY FIRE WEATHER HAZARDS.
ANOTHER QUIET NIGHT WITH MORE CLEARING SHOULD RESULT IN ANOTHER
COOL NIGHT WITH LOW IN THE 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 326 AM CDT FRI APR 29 2016
QUIET WEATHER CONTINUES INTO THE LONG TERM PERIOD. AGAIN UTILIZED
PERSISTENCE INTO THE WEEKEND WITH OUR BLOCKING PATTERN AND
GENERALLY RAISED TEMPERATURES JUST A FEW DEGREES EACH DAY SATURDAY
AND SUNDAY. THE EXCEPTION WAS THE FAR SOUTHWEST...WHICH SHOULD
BEGIN TO RISE A LITTLE QUICKER AS WE LOSE ANY REMAINING SNOW.
AS WE HEAD INTO NEXT WEEK...THE GFS/ECMWF BOTH ADVERTISE A WESTERN
U.S. RIDGE WITH TROUGHING OFF THE PACIFIC COAST AND OVER THE
EASTERN U.S. WE WILL BE RIGHT ON THE TRANSITION OF THE
RIDGE/TROUGH REGIME AND AFTER A MILD BEGINNING OF THE WORK WEEK WE
COULD SEE A LITTLE SETBACK IN TEMPERATURES...ESPECIALLY OVER THE
EASTERN CWA DUE TO A BACKDOOR COLD FRONT ASSOCIATED WITH A CLIPPER
DROPPING INTO THE DEVELOPING EAST COAST TROUGH. WE ARE TALKING
ONLY A FEW DEGREES HERE AND THE FRONT WOULD BE DRY. REALLY THE
ONLY HINT OF ANY PRECIPITATION THROUGH THE WEEK IS WITH A LEADING
WAVE DROPPING DOWN THE BUILDING UPPER RIDGE ON MONDAY. THE ECMWF
SHOWS THIS WAVE DROPPING FARTHER WEST ACROSS NORTH DAKOTA AND
COULD RESULT IN A SHOWER OR TWO. THE GFS TAKES IT MUCH FARTHER
EAST AND IS DRY ACROSS THE CWA. RIGHT NOW A MODEL BLEND SOLUTION
DOES NOT CREATE ENOUGH SUPPORT FOR A MENTION OF SHOWERS. THEN LATE
IN THE WORK WEEK THE UPPER RIDGE BEGINS TO BREAK DOWN AND MODELS
WANT TO BRING A LITTLE QPF INTO THE WESTERN CWA FRIDAY NIGHT.
WOULD NOT BE SURPRISED IF THIS DOES NOT COME TO FRUITION GIVEN THE
DRY ATMOSPHERE AND RIDGING STILL HOLDING ON OVER EASTERN MONTANA
LATE IN THE WORK WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 326 AM CDT FRI APR 29 2016
VFR CIGS/VSBYS THROUGH THE PERIOD. SCT/BKN MID LEVEL CLOUDS ALONG
WITH NORTHEAST TO EAST WINDS AROUND 10KT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS Tulsa OK
632 PM CDT SAT APR 30 2016
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Lower ceilings currently across NW AR will quickly dissipiate with
clear skies and light winds prevailing overnight. This will allow
patchy fog to develop especially across NW AR where flight
conditions are most likely to be impacted. VFR conditions expected
by mid morning Sunday.
&&
.PREV DISCUSSION... /ISSUED 242 PM CDT SAT APR 30 2016/
DISCUSSION...
At 2 PM, the surface cold front was draped from just east of the
I-49 corridor in NW AR south to the Arklatex. Moderate instability
/1000-2000 J/KG of CAPE/ resides east of the boundary as it slowly
moves east. 17Z SGF sounding was not impressive from a deep layer
shear perspective as our area resides in a relative minimum in
mid level flow. The latest HRRR suggests some convection
developing on the eastern fringes of the forecast area. This still
suggests severe /mainly hail/ potential will be to the east with
storms moving and maturing east of our area.
The polar front will slide thru the region on Sunday in the wake
of the upper low to our north. Another piece of energy rotating
around the base of the parent western CONUS upper trough will
slide across the central Plains Sunday night...weakening with time
as it shears out. Lift north of the surface front will bring the
best rain chances down south...with lower chances farther north in
association with weakening mid level frontogenetic band.
Instability will be hard to come by this far north of the surface
front...thus maintained only isolated thunder mention in the
southeast.
Fairly tranquil work week expected as upper pattern transitions
to a deep trough over the East and Gulf with ridging over the
Rockies. Rich Gulf moisture will be scoured out by this pattern
and will take many days to return. The next upper trough will
bring storm chances by the latter part of next weekend into early
next week. However...moisture quality will be subpar for early May
standards. Overall severe event may be limited by this.
Lacy
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 47 68 48 67 / 0 10 30 10
FSM 53 75 52 70 / 10 0 50 20
MLC 50 71 51 67 / 0 0 40 10
BVO 46 66 47 66 / 0 10 30 10
FYV 46 70 48 64 / 10 0 30 10
BYV 48 70 48 63 / 10 10 20 10
MKO 49 71 49 66 / 0 0 30 10
MIO 47 67 47 64 / 0 10 20 10
F10 49 70 50 66 / 0 0 30 10
HHW 55 76 54 70 / 0 0 50 20
&&
.TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS NORMAN OK
1249 PM CDT FRI APR 29 2016
.DISCUSSION...
THE 18Z AVIATION DISCUSSION FOLLOWS....
&&
.AVIATION...
A WARM FRONT JUST S OF THE RED RIVER WILL LIFT SLOWLY N THIS
AFTERNOON...AS A SURFACE LOW MOVES ENE ACROSS S OK. NEAR AND S OF
THE FRONT...THERE IS/WILL BE SOME PARTIAL CLEARING. FARTHER
N...LOW CEILINGS WILL CONTINUE TO BE THE RULE...ALONG WITH
SHRA/TSRA AT TIMES. AFTER 00Z...A DRY SLOT IS FORECAST TO FORM
FROM SW TO NE ACROSS MOST OF N TX AND OK...PRESUMABLY BRINGING
CLEARING CONDITIONS. ALSO...A COLD FRONT WILL SWEEP SE ACROSS OK
THIS EVENING...SHIFTING WINDS TO THE NW. AFTER ABOUT 00Z...MOST
TAF SITES SHOULD BE...AND REMAIN...VFR WITH NEARLY STEADY N-NW
WINDS. STRONG/SEVERE TSRA WILL BE POSSIBLE THIS AFTERNOON AND
EVENING. WHERE TSRA ARE MENTIONED IN TAFS AFTER 20Z...THOSE TSRA
MAY WELL BE SEVERE. OVERALL...CONFIDENCE IN THE FORECAST IS FAIRLY
LOW...ESPECIALLY REGARDING TIMING AND CEILINGS...PRIOR TO 00Z.
CONFIDENCE THEN BEGINS TO IMPROVE SIGNIFICANTLY OVERNIGHT.
CMS
&&
.PREV DISCUSSION... /ISSUED 1225 PM CDT FRI APR 29 2016/
UPDATE...
ADJUSTED THE MAX TEMP GRIDS A LITTLE BIT COOLER FOR TODAY ACROSS
NORTHWEST AND FAR NORTHERN OKLAHOMA, AS WELL AS THE CLOUD GRIDS
FOR DECREASING CLOUDINESS ACROSS WESTERN NORTH TEXAS.
PREV DISCUSSION... /ISSUED 1134 AM CDT FRI APR 29 2016/
DISCUSSION...
NO CHANGES HAVE BEEN MADE TO THE FORECAST GRIDS IN THE SHORT TERM.
ISOLATED STRONG TO SEVERE THUNDERSTORMS PERSIST ACROSS NORTHWEST
OKLAHOMA IN ASSOCIATION WITH THE UPPER LEVEL TROUGH. THE BIGGEST
CONCERN WILL BE CONVECTION DEVELOPING ALONG A WARM FRONT,
CURRENTLY STRETCHED ACROSS NORTH TEXAS, AS WELL AS THE UNCERTAINTY
TO THE NORTHWARD DISPLACEMENT OF THE BOUNDARY DURING THE
AFTERNOON. SO FAR, LATEST HRR AND SHORT RANGE RAP & NAM MODELS ALL
LIFT THE WARM FRONT AS FAR NORTH INTO NORTHERN OKLAHOMA, BEFORE
OVERTAKEN BY A COLD FRONT BY LATE THIS EVENING/EARLY SATURDAY
MORNING. THE POTENTIAL FOR STRONG THERMODYNAMIC AND DYNAMIC
FORCING IS IN PLACE, WITH A TONGUE OF MU CAPE VALUES OF 2000-2500
J/KG AND HIGHER THAN MARGINAL LOW AND HIGH BASED SHEAR VALUES, IN
A NEARLY UNCAPPED ENVIRONMENT. THE POTENTIAL CERTAINLY EXIST FOR
SEVERE SUPERCELL THUNDERSTORMS AND THE POTENTIAL FOR A FEW
TORNADOS ALL DEVELOPING ALONG AND JUST AHEAD OF THE WARM FRONT.
THE BIGGEST RISK AREA RIGHT FOR THIS AFTERNOON AND EVENING NOW
EXTENDS FROM I-40 TO SOUTH OF THE RED RIVER, WITH A SLIGHT RISK TO
THE NORTH. OUN WILL BE MAKING A 19Z SPECIAL BALLO0N SOUNDING FOR
THIS EVENT.
PREV DISCUSSION... /ISSUED 431 AM CDT FRI APR 29 2016/
DISCUSSION...
NUMEROUS THUNDERSTORMS EXPECTED TO CONTINUE TOWARD DAYBREAK OVER
MAINLY TWO PARTS OF THE CWA - SOUTHEAST OKLAHOMA IN AREA OF
ENHANCED ELEVATED THETA-E ADVECTION AND ALSO ACROSS NORTHWEST
OKLAHOMA AS LEAD S/WV PUSHES OUT OF NORTHEAST NM. IN
BETWEEN...EXPECTING MORE SCATTERED NATURE OF SHOWERS AND STORMS AT
LEAST THROUGH MID-MORNING. THERE CONTINUES TO BE DIFFERENCES
BETWEEN OPERATIONAL AND CAM MODELS WITH REGARDS TO MORNING
CONVECTION ALONG AND AHEAD OF DRYLINE. CURRENTLY APPEARS THAT THE
MORE AGGRESSIVE MODELS ARE TOO AGGRESSIVE AND PORTIONS OF CENTRAL
AND SOUTHWEST OKLAHOMA INCLUDING PARTS OF WESTERN NORTH TEXAS
BECOME CONVECTION FREE FOR MUCH OF THE DAY. THIS SCENARIO
INCREASES THE SEVERE CONVECTIVE POTENTIAL FOR THE SOUTHERN HALF OF
THE ENHANCED RISK AREA WHICH INCLUDES THE OKLAHOMA CITY
METRO...DOWN TOWARD WICHITA FALLS AND AREAS EAST THROUGH
ARDMORE...ADA...AND DURANT. SUITE OF WRF CAMS SURGE THE DRYLINE
EASTWARD THIS MORNING AND EARLY AFTERNOON...CONVECTING WELL EAST
OF INTERSTATE-35. THIS FORECAST APPEAR TOO FAR EAST WITH
INITIATION AND PREFERENCE WAS GIVEN TO HRRR/RAP DEVELOPING
CONVECTION FARTHER WEST OVER CENTRAL/SOUTHCENTRAL OKLAHOMA. WITH
SUCCESSIVE RUNS THIS MORNING...THIS TREND COULD CHANGE BUT POPS
WERE CONFIGURED CLOSER TO THIS LATTER SCENARIO. GIVEN PROGD
LOCATION OF SURFACE CYCLONE AND WARM FRONT...THIS WOULD YIELD
POTENTIAL FOR SURFACE BASED SUPERCELL DEVELOPMENT OVER CENTRAL AND
SOUTH-CENTRAL PORTIONS OF OKLAHOMA WHICH COINCIDES WITH THE
GREATER TORNADO PROBS VIA SPC. A FLY IN THE OINTMENT IS AMOUNT OF
CONVECTION PROGD FOR NORTHERN AND CENTRAL TEXAS THIS AFTERNOON
WHICH COULD DISRUPT/PREVENT SUSTAINED CONVECTION FARTHER NORTH.
OUTSIDE OF ACTIVE WEATHER TODAY AND THIS EVENING...LITTLE CHANGE
TO PREVIOUS FORECAST. FAST MOVING SYSTEM STILL PROGD TO BRING
RAIN/STORM CHANCES TO THE REGION LATE SUNDAY THROUGH MONDAY.
SEVERE WEATHER WITH THIS PARTICULAR EPISODE IS UNLIKELY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 72 51 73 47 / 60 30 10 0
HOBART OK 75 46 72 45 / 40 30 0 0
WICHITA FALLS TX 81 51 76 49 / 40 20 0 0
GAGE OK 53 41 67 41 / 70 30 0 10
PONCA CITY OK 64 50 72 45 / 60 80 10 0
DURANT OK 77 61 79 54 / 70 60 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
68/23/23
AREA FORECAST DISCUSSION
NWS NORMAN OK
1225 PM CDT FRI APR 29 2016
.UPDATE...
ADJUSTED THE MAX TEMP GRIDS A LITTLE BIT COOLER FOR TODAY ACROSS
NORTHWEST AND FAR NORTHERN OKLAHOMA, AS WELL AS THE CLOUD GRIDS
FOR DECREASING CLOUDINESS ACROSS WESTERN NORTH TEXAS.
&&
.PREV DISCUSSION... /ISSUED 1134 AM CDT FRI APR 29 2016/
DISCUSSION...
NO CHANGES HAVE BEEN MADE TO THE FORECAST GRIDS IN THE SHORT TERM.
ISOLATED STRONG TO SEVERE THUNDERSTORMS PERSIST ACROSS NORTHWEST
OKLAHOMA IN ASSOCIATION WITH THE UPPER LEVEL TROUGH. THE BIGGEST
CONCERN WILL BE CONVECTION DEVELOPING ALONG A WARM FRONT,
CURRENTLY STRETCHED ACROSS NORTH TEXAS, AS WELL AS THE UNCERTAINTY
TO THE NORTHWARD DISPLACEMENT OF THE BOUNDARY DURING THE
AFTERNOON. SO FAR, LATEST HRR AND SHORT RANGE RAP & NAM MODELS ALL
LIFT THE WARM FRONT AS FAR NORTH INTO NORTHERN OKLAHOMA, BEFORE
OVERTAKEN BY A COLD FRONT BY LATE THIS EVENING/EARLY SATURDAY
MORNING. THE POTENTIAL FOR STRONG THERMODYNAMIC AND DYNAMIC
FORCING IS IN PLACE, WITH A TONGUE OF MU CAPE VALUES OF 2000-2500
J/KG AND HIGHER THAN MARGINAL LOW AND HIGH BASED SHEAR VALUES, IN
A NEARLY UNCAPPED ENVIRONMENT. THE POTENTIAL CERTAINLY EXIST FOR
SEVERE SUPERCELL THUNDERSTORMS AND THE POTENTIAL FOR A FEW
TORNADOS ALL DEVELOPING ALONG AND JUST AHEAD OF THE WARM FRONT.
THE BIGGEST RISK AREA RIGHT FOR THIS AFTERNOON AND EVENING NOW
EXTENDS FROM I-40 TO SOUTH OF THE RED RIVER, WITH A SLIGHT RISK TO
THE NORTH. OUN WILL BE MAKING A 19Z SPECIAL BALLO0N SOUNDING FOR
THIS EVENT.
PREV DISCUSSION... /ISSUED 431 AM CDT FRI APR 29 2016/
DISCUSSION...
NUMEROUS THUNDERSTORMS EXPECTED TO CONTINUE TOWARD DAYBREAK OVER
MAINLY TWO PARTS OF THE CWA - SOUTHEAST OKLAHOMA IN AREA OF
ENHANCED ELEVATED THETA-E ADVECTION AND ALSO ACROSS NORTHWEST
OKLAHOMA AS LEAD S/WV PUSHES OUT OF NORTHEAST NM. IN
BETWEEN...EXPECTING MORE SCATTERED NATURE OF SHOWERS AND STORMS AT
LEAST THROUGH MID-MORNING. THERE CONTINUES TO BE DIFFERENCES
BETWEEN OPERATIONAL AND CAM MODELS WITH REGARDS TO MORNING
CONVECTION ALONG AND AHEAD OF DRYLINE. CURRENTLY APPEARS THAT THE
MORE AGGRESSIVE MODELS ARE TOO AGGRESSIVE AND PORTIONS OF CENTRAL
AND SOUTHWEST OKLAHOMA INCLUDING PARTS OF WESTERN NORTH TEXAS
BECOME CONVECTION FREE FOR MUCH OF THE DAY. THIS SCENARIO
INCREASES THE SEVERE CONVECTIVE POTENTIAL FOR THE SOUTHERN HALF OF
THE ENHANCED RISK AREA WHICH INCLUDES THE OKLAHOMA CITY
METRO...DOWN TOWARD WICHITA FALLS AND AREAS EAST THROUGH
ARDMORE...ADA...AND DURANT. SUITE OF WRF CAMS SURGE THE DRYLINE
EASTWARD THIS MORNING AND EARLY AFTERNOON...CONVECTING WELL EAST
OF INTERSTATE-35. THIS FORECAST APPEAR TOO FAR EAST WITH
INITIATION AND PREFERENCE WAS GIVEN TO HRRR/RAP DEVELOPING
CONVECTION FARTHER WEST OVER CENTRAL/SOUTHCENTRAL OKLAHOMA. WITH
SUCCESSIVE RUNS THIS MORNING...THIS TREND COULD CHANGE BUT POPS
WERE CONFIGURED CLOSER TO THIS LATTER SCENARIO. GIVEN PROGD
LOCATION OF SURFACE CYCLONE AND WARM FRONT...THIS WOULD YIELD
POTENTIAL FOR SURFACE BASED SUPERCELL DEVELOPMENT OVER CENTRAL AND
SOUTH-CENTRAL PORTIONS OF OKLAHOMA WHICH COINCIDES WITH THE
GREATER TORNADO PROBS VIA SPC. A FLY IN THE OINTMENT IS AMOUNT OF
CONVECTION PROGD FOR NORTHERN AND CENTRAL TEXAS THIS AFTERNOON
WHICH COULD DISRUPT/PREVENT SUSTAINED CONVECTION FARTHER NORTH.
OUTSIDE OF ACTIVE WEATHER TODAY AND THIS EVENING...LITTLE CHANGE
TO PREVIOUS FORECAST. FAST MOVING SYSTEM STILL PROGD TO BRING
RAIN/STORM CHANCES TO THE REGION LATE SUNDAY THROUGH MONDAY.
SEVERE WEATHER WITH THIS PARTICULAR EPISODE IS UNLIKELY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 51 73 47 69 / 30 10 0 0
HOBART OK 46 72 45 68 / 30 0 0 10
WICHITA FALLS TX 51 76 49 72 / 20 0 0 0
GAGE OK 41 67 41 62 / 30 0 10 20
PONCA CITY OK 50 72 45 67 / 80 10 0 0
DURANT OK 61 79 54 74 / 60 20 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
68/23
AREA FORECAST DISCUSSION
NWS NORMAN OK
1134 AM CDT FRI APR 29 2016
.DISCUSSION...
NO CHANGES HAVE BEEN MADE TO THE FORECAST GRIDS IN THE SHORT TERM.
ISOLATED STRONG TO SEVERE THUNDERSTORMS PERSIST ACROSS NORTHWEST
OKLAHOMA IN ASSOCIATION WITH THE UPPER LEVEL TROUGH. THE BIGGEST
CONCERN WILL BE CONVECTION DEVELOPING ALONG A WARM FRONT,
CURRENTLY STRETCHED ACROSS NORTH TEXAS, AS WELL AS THE UNCERTAINTY
TO THE NORTHWARD DISPLACEMENT OF THE BOUNDARY DURING THE
AFTERNOON. SO FAR, LATEST HRR AND SHORT RANGE RAP & NAM MODELS ALL
LIFT THE WARM FRONT AS FAR NORTH INTO NORTHERN OKLAHOMA, BEFORE
OVERTAKEN BY A COLD FRONT BY LATE THIS EVENING/EARLY SATURDAY
MORNING. THE POTENTIAL FOR STRONG THERMODYNAMIC AND DYNAMIC
FORCING IS IN PLACE, WITH A TONGUE OF MU CAPE VALUES OF 2000-2500
J/KG AND HIGHER THAN MARGINAL LOW AND HIGH BASED SHEAR VALUES, IN
A NEARLY UNCAPPED ENVIRONMENT. THE POTENTIAL CERTAINLY EXIST FOR
SEVERE SUPERCELL THUNDERSTORMS AND THE POTENTIAL FOR A FEW
TORNADOS ALL DEVELOPING ALONG AND JUST AHEAD OF THE WARM FRONT.
THE BIGGEST RISK AREA RIGHT FOR THIS AFTERNOON AND EVENING NOW
EXTENDS FROM I-40 TO SOUTH OF THE RED RIVER, WITH A SLIGHT RISK TO
THE NORTH. OUN WILL BE MAKING A 19Z SPECIAL BALLO0N SOUNDING FOR
THIS EVENT.
&&
.PREV DISCUSSION... /ISSUED 431 AM CDT FRI APR 29 2016/
DISCUSSION...
NUMEROUS THUNDERSTORMS EXPECTED TO CONTINUE TOWARD DAYBREAK OVER
MAINLY TWO PARTS OF THE CWA - SOUTHEAST OKLAHOMA IN AREA OF
ENHANCED ELEVATED THETA-E ADVECTION AND ALSO ACROSS NORTHWEST
OKLAHOMA AS LEAD S/WV PUSHES OUT OF NORTHEAST NM. IN
BETWEEN...EXPECTING MORE SCATTERED NATURE OF SHOWERS AND STORMS AT
LEAST THROUGH MID-MORNING. THERE CONTINUES TO BE DIFFERENCES
BETWEEN OPERATIONAL AND CAM MODELS WITH REGARDS TO MORNING
CONVECTION ALONG AND AHEAD OF DRYLINE. CURRENTLY APPEARS THAT THE
MORE AGGRESSIVE MODELS ARE TOO AGGRESSIVE AND PORTIONS OF CENTRAL
AND SOUTHWEST OKLAHOMA INCLUDING PARTS OF WESTERN NORTH TEXAS
BECOME CONVECTION FREE FOR MUCH OF THE DAY. THIS SCENARIO
INCREASES THE SEVERE CONVECTIVE POTENTIAL FOR THE SOUTHERN HALF OF
THE ENHANCED RISK AREA WHICH INCLUDES THE OKLAHOMA CITY
METRO...DOWN TOWARD WICHITA FALLS AND AREAS EAST THROUGH
ARDMORE...ADA...AND DURANT. SUITE OF WRF CAMS SURGE THE DRYLINE
EASTWARD THIS MORNING AND EARLY AFTERNOON...CONVECTING WELL EAST
OF INTERSTATE-35. THIS FORECAST APPEAR TOO FAR EAST WITH
INITIATION AND PREFERENCE WAS GIVEN TO HRRR/RAP DEVELOPING
CONVECTION FARTHER WEST OVER CENTRAL/SOUTHCENTRAL OKLAHOMA. WITH
SUCCESSIVE RUNS THIS MORNING...THIS TREND COULD CHANGE BUT POPS
WERE CONFIGURED CLOSER TO THIS LATTER SCENARIO. GIVEN PROGD
LOCATION OF SURFACE CYCLONE AND WARM FRONT...THIS WOULD YIELD
POTENTIAL FOR SURFACE BASED SUPERCELL DEVELOPMENT OVER CENTRAL AND
SOUTH-CENTRAL PORTIONS OF OKLAHOMA WHICH COINCIDES WITH THE
GREATER TORNADO PROBS VIA SPC. A FLY IN THE OINTMENT IS AMOUNT OF
CONVECTION PROGD FOR NORTHERN AND CENTRAL TEXAS THIS AFTERNOON
WHICH COULD DISRUPT/PREVENT SUSTAINED CONVECTION FARTHER NORTH.
OUTSIDE OF ACTIVE WEATHER TODAY AND THIS EVENING...LITTLE CHANGE
TO PREVIOUS FORECAST. FAST MOVING SYSTEM STILL PROGD TO BRING
RAIN/STORM CHANCES TO THE REGION LATE SUNDAY THROUGH MONDAY.
SEVERE WEATHER WITH THIS PARTICULAR EPISODE IS UNLIKELY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 72 51 73 47 / 60 30 10 0
HOBART OK 75 46 72 45 / 40 30 0 0
WICHITA FALLS TX 81 51 76 49 / 40 20 0 0
GAGE OK 62 41 67 41 / 70 30 0 10
PONCA CITY OK 68 50 72 45 / 60 80 10 0
DURANT OK 77 61 79 54 / 70 60 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
68/23
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1054 PM CDT SAT APR 30 2016
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 311 PM CDT SAT APR 30 2016
UPPER LEVEL LOW PRESENTLY SPINNING THROUGH CENTRAL NEBRASKA WILL
MOVE ONLY SLOWLY EASTWARD TONIGHT AND TOMORROW...BECOMING SITUATED
OVER NORTHERN ILLINOIS BY SUNDAY EVENING. CURRENT RADAR SHOWING MOST
OF THE RAINFALL CONCENTRATED ALONG THE INTERSTATE 90 CORRIDOR INTO
SOUTH CENTRAL SD...AS RAINFALL HAS BEEN CUT OFF THROUGH MOST OF
NORTHWEST IA AND THE LOWER MISSOURI VALLEY. HAVE HAD FEW STRONGER
WIND GUSTS OVER THE PAST HOUR THROUGH NORTHWEST IOWA AS THE SHOWERS
ENDED AND STRONGER WINDS ALOFT MIXED DOWN. HRRR WIND GUST GUIDANCE
SHOWING THESE ISOLATED 40 TO 50 MPH GUSTS CONTINUING INTO LATE
AFTERNOON. OTHERWISE...SHORT TERM MODELS INDICATE THAT ADDITIONAL
SHOWER DEVELOPMENT WILL OCCUR OVER EASTERN NEBRASKA DURING THE LATER
AFTERNOON...LIFTING BACK INTO OUR AREA BY EARLY EVENING. THESE
SHOWERS WILL LINGER IN AREAS SOUTH OF INTERSTATE 90 OVERNIGHT WHERE
THE BETTER MIDLEVEL THETA E ADVECTION IS LOCATED...THOUGH
DIMINISHING FROM NORTH TO SOUTH DURING THE NIGHT AS THE UPPER LEVEL
LOW SHIFTS EASTWARD/FORCING WEAKENS/AND DRIER AIR IS PULLED
SOUTHWARD. NORTHEASTERLY WINDS WILL BEGIN TO EASE OFF DURING THE
EVENING...AND LOOKING AT LOWS MAINLY UPPER 30S TO LOWER 40.
ON SUNDAY THE LOW CONTINUES TO SLOWLY PULL AWAY FROM THE AREA...WITH
RAIN CHANCES CONTINUING THROUGH THE LOWER MISSOURI RIVER VALLEY INTO
NORTHWEST IOWA DURING THE FIRST PART OF THE DAY...THOUGH MODELS EVEN
LINGER SOME QPF THROUGH OUR FAR NORTHWESTERN IOWA ZONES INTO THE
AFTERNOON. WITH SLIGHTLY MORE INSTABILITY ANY OF THIS ACTIVITY WOULD
BE OF A MORE SHOWERY NATURE. THERMAL PROFILES DO WARM ON
SUNDAY...AND LOOKING AT TEMPERATURES A LITTLE WARMER...TOPPING OUT IN
THE MID 50S TO LOWER 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 311 PM CDT SAT APR 30 2016
A WEAK RIDGE OF HIGH PRESSURE WILL WORK ACROSS THE CWA ON SATURDAY
NIGHT LEADING TOWARDS CLEARING SKIES AND LIGHT WINDS. ADDED SOME
PATCHY FOG OVER PARTS OF NORTHWEST IOWA...SOUTHWEST MINNESOTA AND
SOUTHEAST SOUTH DAKOTA AS THE GROUND IS ALSO VERY SATURATED.
LOWS DOWN IN TO THE THE MID AND UPPER 30S.
MONDAY SHOULD BE A NICE DAY...POSSIBLY WAITING UNTIL LATE MORNING
FOR THE SUN IF THE FOG IS MORE WIDESPREAD. LOWERED HIGHS JUST A
TOUCH OVER NORTHWEST IOWA WHERE THE FOG COULD LINGER A LITTLE
LONGER. BASICALLY NEAR 70 IN CENTRAL SOUTH DAKOTA TO 60 TO 65 IN
NORTHWEST IOWA.
MONDAY NIGHT INTO TUESDAY THE MODELS DIVERGE SLIGHTLY...BUT IT DOES
MAKE SOME DIFFERENCE ON HIGH TEMPERATURES POTENTIAL. THE GFS IS MOST
AGGRESSIVE AT WARMING AND DEVELOPING STRONGER NORTHWEST
WINDS...WHILE THE NAM KEEPS THE BETTER MIXING IN THE NORTHERN CWA
AND THE ECMWF IS VERY SLOW TO SET UP ACROSS THE AREA. REGARDLESS
WILL BE A WARM DAY AND WILL LEAN TOWARDS THE NAM TIMING WHICH WILL
KEEP SOME OF THE WARMEST HIGHS FROM HURON TO MARSHALL MINNESOTA AND
THE SLIGHTLY COOLER READINGS IN NORTHWEST IOWA.
IN THE OUTER PERIODS(WEDNESDAY THROUGH SATURDAY)...A FAIRLY STRONG
DIGGING TROUGH ACROSS THE OHIO VALLEY WILL BRING STRONGER NORTHWEST
FLOW ALOFT TO THE AREA ON WEDNESDAY...BEFORE GIVING WAY TO UPPER
LEVEL RIDGING THURSDAY AND FRIDAY. THIS TIME AROUND THE MODELS ARE A
LITTLE FASTER IN SWINGING AN UPPER LEVEL TROUGH ONTO THE PLAINS
SATURDAY...ALBEIT THE AMOUNT OF AGREEMENT AMONGST THE MODELS IS
MARGINAL. THE ECMWF IS MUCH MORE AGGRESSIVE IN BRINGING A FULL
LATITUDE TROUGH THROUGH THE PLAINS THIS WEEKEND WHILE THE GFS STICKS
WITH SOMETHING CLOSER TO AN OMEGA BLOCKING PATTERN WHICH WAS ALREADY
IN PLACE THURSDAY AND FRIDAY. FOR NOW WILL LEAN MORE CLOSELY TOWARDS
THE MORE GENERAL BREAK DOWN OF THE OMEGA BLOCKING PATTERN IN THE GFS
VERSUS THE MORE AGGRESSIVE PATTERN IN THE ECMWF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1052 PM CDT SAT APR 30 2016
BAND OF RAIN CONTINUES TO WEAKEN AND WILL VERY SLOWLY SHIFT
SOUTHEAST THROUGH THE OVERNIGHT HOURS...LINGERING INTO MID MORNING
IN PORTIONS OF NORTHWEST IOWA. MVFR TO IFR CEILINGS WILL PERSIST
WITH THIS RAIN BAND...BUT WILL ALSO SEE IMPROVEMENT AS THE SYSTEM
EXITS. CLEARING WILL ALSO ARRIVE FROM NORTHWEST TO SOUTHEAST ON
SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...JM
LONG TERM...08
AVIATION...
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
759 PM CDT SAT APR 30 2016
.DISCUSSION...
UPDATE WILL BE OUT SHORTLY. CURRENTLY NO SHOWERS OR THUNDERSTORMS
ACROSS THE AREA. HOWEVER...THERE IS SEVERE WEATHER JUST TO THE
WEST. IT IS MOVING TOWARD NORTHEAST ARKANSAS AND THE MISSOURI
BOOTHEEL. THERE IS A CHANCE THAT THESE MAY BE
SEVERE...HOWEVER...CURRENT CONDITIONS INDICATE THE ATMOSPHERE IS
MORE STABLE OVER THE MID-SOUTH THAN CENTRAL ARKANSAS. WILL
CONTINUE TO MONITOR STORMS.
LOWERED POPS THIS EVENING FOR NORTH MISSISSIPPI AS NOT EXPECTING
ANYTHING TILL AFTER MIDNIGHT. AFTER MIDNIGHT IT IS POSSIBLE FOR
SOME STORMS TO DEVELOP.
ALSO THERE IS THE POSSIBILITY OF SOME PATCHY FOG OVERNIGHT IN SOME
AREAS...SO INCLUDED THAT IN MOST AREAS WITH THE EXCEPTION OF NORTH
MISSISSIPPI.
TLSJR
&&
.PREV DISCUSSION... /ISSUED 642 PM CDT SAT APR 30 2016/
UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION
PREV DISCUSSION... /ISSUED 256 PM CDT SAT APR 30 2016/
DISCUSSION...
CURRENT RADAR IMAGES SHOW AN AREA OF SHOWERS AND THUNDERSTORMS
STRETCHING FROM NEAR BATESVILLE AND OXFORD SOUTH TO THE GULF
COAST. MORE OF THESE SHOWERS AND THUNDERSTORMS WILL ROTATE INTO
NORTHEAST MISSISSIPPI THIS AFTERNOON. SOME OF THESE MAY BECOME
STRONG TO SEVERE.
MEANWHILE...A COLD FRONT STRETCHES ACROSS SOUTHWEST MISSOURI. THE
LATEST HRRR SHOWS SOME DEVELOPMENT ALONG THE FRONT THAT WILL MOVE
INTO NORTHEAST ARKANSAS AROUND 7 PM. SOME OF THESE STORMS COULD
ALSO BE STRONG TO SEVERE.
MODELS ARE HAVING A HARD TIME WITH THIS PATTERN AND DIFFERENCES
BEGIN ON HOW FAR THE FRONT WILL MOVE INTO THE MIDSOUTH. THE NAM
STALLS THE FRONT FROM PARIS TO MEMPHIS WHILE THE GFS STALLS IT
FURTHER SOUTH. WHEREVER THE FRONT STALLS...SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG THE FRONT BY THE AFTERNOON INTO
THE EVENING HOURS.
A SFC LOW WILL DEVELOP ALONG THE FRONT IN NORTHERN LOUISIANA AND
TRACK NORTHEASTWARD. THIS WILL BRING WIDESPREAD SHOWERS AND
THUNDERSTORMS INTO THE MIDSOUTH LATE SUNDAY NIGHT INTO MONDAY.
HAVE BUMPED UP POPS TO LIKELY FROM MEMPHIS SOUTHWARD.
THE FRONT WILL BEGIN SHIFTING SOUTHWARD MONDAY NIGHT INTO TUESDAY.
COOLER AND DRIER AIR WILL FILTER INTO THE MIDSOUTH BEHIND THE
FRONT.
BEYOND TUESDAY...A LARGE UPPER TROF WILL SET UP OVER THE OHIO
VALLEY. THE TROF WILL EVENTUALLY EVOLVE INTO A CUT OFF INTO AN UPPER
LOW. AT THE SFC...HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST
WHICH WILL KEEP NORTHERLY WINDS OCCURRING ACROSS THE MIDSOUTH.
TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS RANGING FROM AROUND
70 TO THE MID 70S. BY SATURDAY...AN UPPER RIDGE WILL BEGIN
SHIFTING EASTWARD ALLOWING TEMPERATURES TO WARM UP BACK TO NORMAL.
KRM
&&
.AVIATION...
SEVERAL SHORT TERM/HIGH RES MODELS INDICATE INCREASING TSRA
ACTIVITY AFTER 00Z FOR ALL FOUR TAF SITES.. HOWEVER THERE IS NOT
ENOUGH CONFIDENCE ATTM TO ADD TSRA TO TAFS. DUE TO THE ISOLATED
NATURE OF THESE STORMS... DECIDED ON VCTS FOR ALL 4 SITES. BEST
CHANCES HOWEVER WILL BE AT KJBR WITH THE STORMS CURRENTLY IN NORTH
CENTRAL ARKANSAS MOVING TOWARDS THE REGION. LIFR CONDITIONS ARE
ALSO POSSIBLE OVERNIGHT WITH THE DEVELOPMENT OF FOG AND LOWERED CEILINGS
AT EACH SITE. FOG SHOULD DISSIPATE AND CEILINGS SHOULD LIFT
TOMORROW MORNING. A FRONTAL PASSAGE WILL TURN WINDS FROM THE SOUTH
TO THE NORTHWEST TOMORROW.
JPM3
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
642 PM CDT SAT APR 30 2016
.UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 256 PM CDT SAT APR 30 2016/
DISCUSSION...
CURRENT RADAR IMAGES SHOW AN AREA OF SHOWERS AND THUNDERSTORMS
STRETCHING FROM NEAR BATESVILLE AND OXFORD SOUTH TO THE GULF
COAST. MORE OF THESE SHOWERS AND THUNDERSTORMS WILL ROTATE INTO
NORTHEAST MISSISSIPPI THIS AFTERNOON. SOME OF THESE MAY BECOME
STRONG TO SEVERE.
MEANWHILE...A COLD FRONT STRETCHES ACROSS SOUTHWEST MISSOURI. THE
LATEST HRRR SHOWS SOME DEVELOPMENT ALONG THE FRONT THAT WILL MOVE
INTO NORTHEAST ARKANSAS AROUND 7 PM. SOME OF THESE STORMS COULD
ALSO BE STRONG TO SEVERE.
MODELS ARE HAVING A HARD TIME WITH THIS PATTERN AND DIFFERENCES
BEGIN ON HOW FAR THE FRONT WILL MOVE INTO THE MIDSOUTH. THE NAM
STALLS THE FRONT FROM PARIS TO MEMPHIS WHILE THE GFS STALLS IT
FURTHER SOUTH. WHEREVER THE FRONT STALLS...SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG THE FRONT BY THE AFTERNOON INTO
THE EVENING HOURS.
A SFC LOW WILL DEVELOP ALONG THE FRONT IN NORTHERN LOUISIANA AND
TRACK NORTHEASTWARD. THIS WILL BRING WIDESPREAD SHOWERS AND
THUNDERSTORMS INTO THE MIDSOUTH LATE SUNDAY NIGHT INTO MONDAY.
HAVE BUMPED UP POPS TO LIKELYS FROM MEMPHIS SOUTHWARD.
THE FRONT WILL BEGIN SHIFTING SOUTHWARD MONDAY NIGHT INTO TUESDAY.
COOLER AND DRIER AIR WILL FILTER INTO THE MIDSOUTH BEHIND THE
FRONT.
BEYOND TUESDAY...A LARGE UPPER TROF WILL SET UP OVER THE OHIO
VALLEY. THE TROF WILL EVENTUALLY EVOLVE INTO A CUT OFF INTO AN UPPER
LOW. AT THE SFC...HIGH PRESSURE WILL REMAIN OVER THE UPPER MIDWEST
WHICH WILL KEEP NORTHERLY WINDS OCCURRING ACROSS THE MIDSOUTH.
TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS RANGING FROM AROUND
70 TO THE MID 70S. BY SATURDAY...AN UPPER RIDGE WILL BEGIN
SHIFTING EASTWARD ALLOWING TEMPERATURES TO WARM UP BACK TO NORMAL.
KRM
&&
.AVIATION...
SEVERAL SHORT TERM/HIGH RES MODELS INDICATE INCREASING TSRA
ACTIVITY AFTER 00Z FOR ALL FOUR TAF SITES.. HOWEVER THERE IS NOT
ENOUGH CONFIDENCE ATTM TO ADD TSRA TO TAFS. DUE TO THE ISOLATED
NATURE OF THESE STORMS... DECIDED ON VCTS FOR ALL 4 SITES. BEST
CHANCES HOWEVER WILL BE AT KJBR WITH THE STORMS CURRENTLY IN NORTH
CENTRAL ARKANSAS MOVING TOWARDS THE REGION. LIFR CONDITIONS ARE
ALSO POSSIBLE OVERNIGHT WITH THE DEVELOPMENT OF FOG AND LOWERED CEILINGS
AT EACH SITE. FOG SHOULD DISSIPATE AND CEILINGS SHOULD LIFT
TOMORROW MORNING. A FRONTAL PASSAGE WILL TURN WINDS FROM THE SOUTH
TO THE NORTHWEST TOMORROW.
JPM3
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1230 AM CDT FRI APR 29 2016
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...CEILINGS HAVEN/T DROPPED AS LOW AS THE PREVIOUS SET OF
TAFS FORECASTED...AND HAVE BEEN ADJUSTED UPWARDS BASED ON SURFACE
OBSERVATIONS. MVFR IS LIKELY TO PREVAIL THROUGH THE REMAINDER OF
THE OVERNIGHT HOURS WITH LIGHT WINDS IN PLACE. TOMORROW...VFR WILL
DEVELOP AFTER SUNRISE AND PREVAIL WITH BREEZY WINDS. A RETURN TO
MVFR IS LIKELY AFTER SUNSET FRIDAY EVENING.
&&
.PREV DISCUSSION... /ISSUED 658 PM CDT THU APR 28 2016/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...MVFR CIGS HAVE RETURNED TO BRO AND HRL OVER THE PAST
TWO HOURS AS LOW-LVL CLOUDS ROLL IN FROM THE GULF ON SE
FLOW...WHICH SHOWS NICELY ON VIS IMAGERY. MFE STILL HANGING ON TO
VFR WITH OVC033 AS OF LAST HOUR.
HAVE CONTINUED TRENDS FROM PREVIOUS SET OF TAFS WITH A FEW TWEAKS
ON TIMING. SHORT-TERM STATISTICAL GUIDANCE IN GOOD AGREEMENT THAT
IFR CIGS WILL RETURN TO BRO AND HRL AROUND 02-04Z...SO CONFIDENCE
FAIRLY HIGH ON THIS. LESS SO AT MFE SO GOING WITH LOW-END MVFR
CEILINGS OVERNIGHT THERE. WINDS SHOULD STAY UP ENOUGH OVERNIGHT TO
KEEP MUCH FOG FROM FORMING. VISIBILITIES MAY VARY SOMEWHAT THRU
THE NEXT 24HR AS VARYING AMTS OF SMOKY HAZE RIDE UP THROUGH THE
AREA...BUT GENERALLY EXPECTING 4-5 MI.
WINDS WILL PICK UP TO BREEZY CATEGORY WITH GUSTS TO 25KT BY LATE
MORNING FRI. 18Z GFS MODEL WINDS SEEM OVERDONE SO WILL LEAN TOWARD
NAM.
PREV DISCUSSION... /ISSUED 301 PM CDT THU APR 28 2016/
SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...A 500 MB CLOSED LOW
JUST WEST OF THE FOUR CORNERS WILL MOVE EAST ACROSS THE DESERT
SOUTHWEST TONIGHT...PUSHING INTO THE SOUTHERN HIGH PLAINS BY
FRIDAY. THE APPROACH OF THE LOW WILL BE ASSOCIATED WITH A SURFACE
COLD FRONTAL SYSTEM MOVING INTO WEST TEXAS TONIGHT AND FRIDAY.
THAT DEVELOPMENT WILL TIGHTEN UP THE SURFACE PGF...INCREASING SE-S
WINDS TO MODERATE OR BREEZY FROM THE COAST TO THE MID VALLEY ON
FRIDAY
PERSISTENT SE-S LOW LEVEL FLOW COMBINED WITH 500 MB RIDGING THAT
WILL BUILD OVER THE GULF OF MEXICO...AND SUBSIDENT SOUTHWEST FLOW
ALOFT WILL MAINTAIN HIGH TEMPS WELL ABOVE CLIMO FOR LATE APRIL. A
DAY IN THE 90S WEST OF I-69E WILL BE ON TAP FRIDAY...WHEN NORMALS
ARE ONLY IN THE 80S.
DEEP LAYER MOISTURE OVER THE RGV AHEAD OF THIS NEXT 500 MB CLOSED
LOW WILL REMAIN LIMITED WITH ONLY MARGINAL MOISTURE RETURN LATE
TONIGHT INTO FRIDAY. CONSIDERING THE COMBINATION OF THE FAR
NORTHWARD TRACK OF THE CLOSED MID LEVEL LOW AND THE LIMITED MOISTURE
VALUES THROUGH THE SHORT TERM...WILL GO WITH RAIN CHANCES BELOW
MENTIONABLE.
A STABLE LOW LEVEL PROFILE AND MODERATE ONSHORE WINDS WILL SUPPORT
BKN TO OVC LOW LEVEL CLOUDS TONIGHT AND FRIDAY NIGHT...AND WILL ALSO
TRAP HAZE FROM AGRICULTURAL BURNING TO THE SOUTH...REDUCING VSBY
SLIGHTLY. OVERNIGHT LOWS THE NEXT COUPLE OF NIGHTS WILL BE IN THE
70S...HIGHER THAN THE NORMALS IN THE UPPER 60S.
THE LATEST TEXAS COMMISSION ON ENVIRONMENTAL QUALITY`S (TCEQ`S) AIR
QUALITY INDEX (AQI) PLACES THE RGV IN THE CATEGORY OF "UNHEALTHY FOR
SENSITIVE GROUPS" DUE TO THE ONGOING AGRICULTURAL FIRES BURNING
ACROSS MUCH OF MEXICO AND CENTRAL AMERICA. THE SE-S LOW LEVEL FLOW
PATTERN WILL PERSIST THROUGH FRIDAY AND INTO SATURDAY...WITH LIGHTER
WINDS OVER THE WEEKEND...PUSHING SMOKE AND HAZE OVER THE RGV AND
DEGRADING AIR QUALITY. WILL MAINTAIN THE MENTION OF HAZE TONIGHT
THROUGH FRIDAY NIGHT. HAZE WILL MIX WITH SEA AIR AT NIGHT...AS FOG
FORMATION TAKES PLACE DUE TO THE LOWER TEMP/DEWPOINT SPREAD.
LONG TERM /SATURDAY THROUGH THURSDAY/....A SERIES OF UPPER LEVEL
SYSTEMS WILL TRAVEL ACROSS THE WESTERN CONUS INTO THE CENTRAL
PLAINS DURING THE LONG TERM PERIOD. THE SYSTEM OVER THE FOUR
CORNERS WILL PUSH A COLD FRONT ACROSS OUR AREA SATURDAY ENHANCING
CONVECTION OVER THE AREA. PRECIPITABLE WATER VALUES INCREASE TO
ABOVE 1.5 TO 1.7 INCHES ON THE NAM/GFS SOUNDINGS SHOWING AN
INCREASE OF MOISTURE AT LEAST UP TO 850MB OVER THE REGION. THE
BEST CHANCE WILL BE FOCUS OVER THE NORTHERN COUNTIES AND MID
VALLEY BUT LESS OF A CHANCE IN THE LOWER VALLEY. AS THE MAIN LOW
PRESSURE WEAKENS AND LIFTS NE...THE SOUTHWEST FLOW ALOFT RETURNS
WITH DRY AIR IN THE MID LAYERS MAKING ITS WAY INTO THE CWA WHILE
EASTERLY FLOW WILL STILL REMAIN IN THE LOWER LAYERS. LOW LEVEL
MOISTURE WILL STILL BE HIGH BELOW 850 MB AVERAGE OF 70 TO 80
PERCENT WHICH COULD INITIATE A FEW SHOWERS SUNDAY AFTERNOON. DRY
LINE WILL BEGIN TO SET UP ALONG THE CONTINENTAL DIVIDE AND SIERRA
MADRE OVER MX ENHANCING THUNDERSTORM ACTIVITY INTO NEXT WEEK. THE
POTENTIAL FOR RAIN WILL INCREASE MON OVER S TEXAS AS A
PERTURBATION MOVES ACROSS THE REGION. ONCE AGAIN WED ANOTHER
INFLUX OF MOISTURE OVER MEXICO WILL TRAVEL EAST ENHANCING
CONVECTION ACROSS THE CWA.
MODELS DIFFER INTO EARLY NEXT WEEK WITH THE ARRIVAL OF THE COLD
FRONT. GFS 12Z MODEL RUN SHOWS A DELAY WITH THE FRONT WHILE THE
ECMWF IS MORE PROGRESSIVE. EVENTHOUGH THERE ARE SOME DIFFERENCES...
ABUNDANT MOISTURE WILL BE AVAILABLE AHEAD OF THE FRONT WHICH WILL
ENHANCE THE CONVECTION ACROSS THE CWA FROM MON THROUGH MID WEEK
WITH DRY AIR MOVING IN.
MARINE...NOW THROUGH FRIDAY NIGHT...HIGH PRESSURE OVER THE GULF
WILL INTERACT WITH PRESSURE FALLS OVER THE SOUTHERN HIGH PLAINS...
RESULTING IN HIGHER WINDS AND SEAS THROUGH FRIDAY NIGHT. SMALL
CRAFT ADVISORY CONDITIONS WILL BE POSSIBLE TOMORROW...FRIDAY...WITH
MORNING WINDS IN THE 20 TO 25 KT RANGE. WINDS WILL DECREASE FRIDAY
NIGHT...BUT WAVE HEIGHTS ON THE GULF MAY REMAIN SEVEN FEET OR
ABOVE THROUGH THE NIGHT.
SATURDAY THROUGH THURSDAY...A FRONT WILL MOVE THROUGH THE LOWER
TEXAS COAST SATURDAY ENHANCING SHOWERS AND THUNDERSTORMS ACROSS THE GULF
WATERS. EXPECT SEAS GRADUALLY LOWERING TO 5 TO 6 FEET AS THE GRADIENT
WEAKENS. THE FRONT WILL BE WEAK ENOUGH THAT WINDS WILL BE MORE EASTERLY
TO SE. SCEC CONDITIONS IS POSSIBLE FOR THE EARLY PORTION OF SATURDAY.
THE WINDS AND SEAS WILL REMAIN MODERATE THROUGH THE REST OF THE WEEK WITH
A WEAK GRADIENT ACROSS THE AREA. A MOISTURE INFLUX AHEAD OF THE NEXT FRONT
MONDAY WILL ENHANCE ANOTHER ROUND OF CONVECTION THROUGH WEDNESDAY BUT
MODEL DIFFERENCES CONTINUE IN THE MODEL GUIDANCE.
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL NOON CDT TODAY FOR GMZ150-155-170-175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
Area Forecast Discussion
National Weather Service Midland/Odessa TX
1225 AM CDT FRI APR 29 2016
.DISCUSSION...
See 06Z aviation discussion below.
&&
.AVIATION...
Southeast winds will shift from the west later tonight then become
gusty during the day before subsiding after 00Z. Satellite shows
patchy MVFR CIGs moving up from the southeast and may affect MAF
the next few hours. A dryline moving east will shift the winds
from the west and will push east any low clouds leaving VFR
conditions through the remainder of the period.
Hennig
&&
.PREV DISCUSSION... /issued 1000 PM CDT THU APR 28 2016/
DISCUSSION...
Latest sfc analysis shows the dryline has bowed westward in its
retreat, and extends from near KSGV-KINK-KPEQ-KFST-KPEQ. This
feature is forecast to retreat a bit more thru at least 06Z, then
begin mixing eastward as stronger westerlies push into the region.
Latest HRRR seems to have finally gotten right after 00Z data came
in, and still hints at convection developing overnight as the
dryline surges east. 00Z NAM agrees as well. W/steep mid-lvl LRs
still forecast, and strong deep lyr shear rounding the base of the
trough, still cannot rule out a svr threat overnight. However,
based on latest HRRR/NAM, we`ll lower POPs some, but keep coverage
the same. In addition, we`ll update other parameters as necessary,
and button up the fire wx grids w/the expiration of the RFW.
Updates out shortly.
PREV DISCUSSION... /issued 215 PM CDT THU APR 28 2016/
DISCUSSION...
WV imagery shows an upper trough digging over the Four Corners
region this afternoon. This has led to increasing SW flow aloft and
the development of a surface low over E NM. Moisture has begun to
surge back west across the area in response to height falls
associated with the upper trough. A sharpening dryline may be a
focus for a few showers and thunderstorms late this afternoon
across the eastern half of the Permian Basin. The best chance for
storms comes later tonight as the dryline retreats west and large
scale lift arrives with the upper trough. Storms are expected to
develop across the western Permian Basin where a Pacific front
will combine with the dryline and move back east across the region
overnight. Some of these storms may be severe with large hail and
damaging winds given steepening lapse rates and an increasing LLJ.
These storms move east quickly Friday morning with windy, dry
conditions filling in across the region Friday afternoon. The base
of the upper trough will graze our area similar to the system this
past Tuesday. Strong westerly winds will mix to the surface,
especially across the higher terrain and adjacent plains. Will
upgrade the High Wind Watch to a warning across the Guadalupe
Mountains. Strong winds are also possible east of the mountains so a
Winds Advisory may be issued on later shifts.
Another upper trough will drop south across Nevada and Arizona
Saturday helping to again draw moisture back west across Texas. At
the same time, a strong cold front will move south across the area
Sunday. Showers and storms are expected to increase along and behind
the front Sunday and Monday as the upper trough approaches.
Temperatures look to cool significantly behind the front due to the
widespread clouds and precip. It is possible many locations may drop
into the 50`s Sunday afternoon and stay there trough Monday! We will
continue to monitor the forecast and make changes if needed.
An upper ridge builds in behind this system, but temperatures stay
cool through midweek before rebounding to near normal late next
week.
FIRE WEATHER...
Warm and dry conditions continue to reside across the area and
with an upper trough to the west there are increasing winds too.
The warm, dry and unstable conditions are reflected in a moderate
Haines Index of 5 and the RFW continues across the Guadalupe
Mountains and southeast New Mexico. Critical fire weather concerns
will expand on Friday to reach farther south into the Davis Mtns
and east into the western PB. Temps will cool, but winds will be
stronger Friday. The Trans Pecos and southeast NM plains continue
to undergo substantial drying and are at or very near the 90th
percentile using ERC-G from TAMFS and certainly supports critical
fire weather.
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 50 79 52 69 / 10 0 0 20
Carlsbad 49 83 50 66 / 0 10 0 30
Dryden 59 91 61 85 / 10 0 0 30
Fort Stockton 54 86 56 82 / 0 0 0 30
Guadalupe Pass 49 74 48 64 / 0 0 0 20
Hobbs 46 77 48 64 / 0 0 0 30
Marfa 39 77 43 79 / 0 10 0 20
Midland Intl Airport 53 84 54 71 / 10 0 10 30
Odessa 55 84 54 71 / 0 0 10 30
Wink 51 87 55 74 / 0 0 0 30
&&
.MAF Watches/Warnings/Advisories...
NM...Red Flag Warning from 11 AM to 9 PM MDT Friday for Guadalupe
Mountains-Southeast Plains.
High Wind Warning from 9 AM to 9 PM MDT Friday for Guadalupe
Mountains of Eddy County.
TX...Red Flag Warning from noon CDT /11 AM MDT/ today to 10 PM CDT /9
PM MDT/ this evening for Andrews-Crane-Davis/Apache
Mountains Area-Ector-Gaines-Guadalupe Mountains-Loving-
Marfa Plateau-Pecos-Reeves County and Upper Trans Pecos-Van
Horn and Highway 54 Corridor-Ward-Winkler.
High Wind Warning from 10 AM CDT /9 AM MDT/ this morning to 10
PM CDT /9 PM MDT/ this evening for Guadalupe Mountains.
&&
$$
99/99/10
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1140 PM CDT THU APR 28 2016
.AVIATION...
AVIATION CONCERNS WILL BE THE DEVELOPMENT OF LOW STRATUS
OVERNIGHT...WHICH IS MORE LIKELY AT KCDS BUT MAY BRING IFR TO
MVFR CEILINGS AT ANY OF THE TERMINALS. ALSO...A LINE OF T-STORMS
WILL MOVE ACROSS THE AREA DURING THE EARLY MORNING HOURS AND WILL
LIKELY IMPACT ALL THE TERMINALS. THEN DURING THE DAY
FRIDAY...GUSTY SOUTHWESTERLY WINDS WILL SPREAD ACROSS THE AREA.
&&
.PREV DISCUSSION... /ISSUED 1020 PM CDT THU APR 28 2016/
UPDATE...
WE FINALLY HAVE A LULL IN CONVECTION AFTER A FAIRLY
AFTERNOON/EVENING. THE DRYLINE IS CURRENTLY RETREATING WESTWARD
AT AN UNEVEN PACE. THERE IS NO LINE OF REFERENCE TO DESCRIBE ITS
CURRENT POSITION. THE BEST DESCRIPTION IS THE DRY SECTOR IS ALL
OF EASTERN NM AS WELL AS A BULGE ACROSS THE SOUTHERN HALF OF
BAILEY COUNTY...ALL OF COCHRAN AND YOAKUM COUNTIES...AND ALL BUT
EASTERN LAMB COUNTY. THERE IS A VERY SHARP MOISTURE GRADIENT WHERE
DEWPOINTS AHEAD OF THE DRYLINE ARE IN THE MID 40S TO UPPER 50S
WHILE DEWPOINTS BEHIND THE DRYLINE ARE LUCKY IF THEY ARE IN THE
20S. THE MAIN UPPER LEVEL FORCING FROM THE APPROACHING LOW IS
STILL WELL TO OUR WEST AND WILL NOT BE HERE TILL SOME TIME AROUND
OR AFTER MIDNIGHT...MOST LIKELY THE LATER. HI RES MODELS SUCH AS
THE HRRR AND THE 00Z NAM CONTINUE TO SHOW CONVECTIVE INITIATION
MUCH FARTHER WEST THAN PREVIOUSLY ANTICIPATED. GIVEN THE CURRENT
SPEED OF THE RETREATING DRYLINE I WOULD HAVE TO AGREE WITH THE
MODELS. THE CURRENT THOUGHT IS THAT THE FIRST CONVECTION TO
GO...AS WELL AS BE THE HEAVIEST/STRONGEST...WILL BE OVER
COCHRAN/LAMB COUNTIES WHERE THERE IS A BULGE IN THE DRYLINE. THIS
BULGE APPEARS TO HAVE CREATED A MESO SURFACE LOW CENTERED OVER
ROOSEVELT COUNTY, NM SHOULD SHOULD PROVIDE AMPLE SURFACE BASED
LIFT. THE MAIN STORM MODE APPEARS TO BE LINEAR AS THE DRYLINE
PROGRESSES EASTWARD THROUGH THE LATE OVERNIGHT/EARLY MORNING
HOURS. WHILE HAIL WILL CONTINUE TO BE THE MAIN THREAT A FEW
TORNADOES CANNOT BE RULED OUT ESPECIALLY ACROSS THE EASTERN HALF
OF THE FA. FORECAST HODOGRAPHS ARE CURVED IN NATURE STARTING JUST
WEST OF THE I27 CORRIDOR AND INCREASE THE FARTHER EAST YOU GO.
THE FORECAST WILL BE UPDATED TO REFLECT CURRENT CONDITIONS
FAVORING CONVECTIVE DEVELOPMENT FURTHER WEST. A MENTION OF SEVERE
STORMS WILL CONTINUE IN THE UPDATED FORECAST. ALDRICH
PREV DISCUSSION... /ISSUED 242 PM CDT THU APR 28 2016/
SHORT TERM...
MOISTURE RETURN HAS BEEN FAIRLY ROBUST WITH THETA-E AXIS
EXTENDING JUST WEST OF THE US-87 I-27 CORRIDOR THENCE CURVING BACK
A BIT NORTHWEST TOWARD DIMMITT. CUMULUS HAS DEVELOPED ALONG THE
WESTERN EDGE OF THE AXIS AND THIS IS AN AREA WHICH IS HINTED AT
FOR INITIATION BY MANY OF THE HIGHER RESOLUTION NWP SOLUTIONS.
OVER THE PAST SEVERAL HOURS...THE THETA-E RIDGE HAS BECOME A BIT
MORE N/S ORIENTED AND WHILE THE ORIENTATION OF THE MID LEVEL FLOW
IS NOT NEARLY AS NORMAL TO THE SURFACE BOUNDARY...IT SHOULD REMAIN
FAVORABLE FOR DISCRETE CONVECTION. WINDS CONTINUE TO BACK
ESPECIALLY ACROSS THE NORTHEASTERN SOUTH PLAINS AND NORTHERN
ROLLING PLAINS GIVEN PRESSURE FALLS TO OUR WEST IN RESPONSE TO
APPROACHING UPPER LEVEL LOW. THIS WILL HELP TO INCREASE LOW LEVEL
HELICITY AND ENHANCE RISK OF LOW LEVEL ROTATION. 0-1KM SHEAR IS
NOT TERRIBLY IMPRESSIVE THIS AFTERNOON BUT DOES RAMP UP SHARPLY
FOR THE SECOND ROUND OF SEVERE CONVECTION TONIGHT. HAVE INCREASED
POPS FOR THIS AFTERNOON ACROSS THE EASTERN PART OF THE CWFA ALONG
WITH ATTENDANT MENTION OF SEVERE. THREAT OF
BASEBALLS/70MPH/TORNADOES CONTINUES TO LOOK REASONABLE. OVERALL A
GUARDED VIGILANCE OF WEATHER CONDITIONS REMAINS WARRANTED THIS
AFTERNOON AND OVERNIGHT.
LONG TERM...
AN UNSETTLED PATTERN OF WEATHER WILL CONTINUE IN THE LONG TERM
FORECAST. A COLD FRONT WILL SWEEP THROUGH THE REGION FRIDAY NIGHT
RELIEVING THE AREA OF DRY CONDITIONS WEST OF THE DRYLINE. THIS
FRONT COMBINED WITH A WEAK SHORT WAVE ALOFT MAY BE ABLE TO
INITIATE SOME CONVECTIVE ACTIVITY IN EASTERN NEW MEXICO TOWARDS
THE TEXAS/NEW MEXICO BORDER. HOWEVER...STORMS WOULD LIKELY HAVE A
DIFFICULT TIME MAINTAINING THEMSELVES GIVEN AN AREA OF UPPER LEVEL
CONVERGENCE ASSOCIATED WITH THE UPPER LEVEL JET STREAK OVERHEAD.
ADDITIONAL SHORT WAVES WILL CONTINUE TO ROTATE AROUND A NEARLY
STATIONARY UPPER LEVEL LOW IN EASTERN COLORADO THIS WEEKEND. THE
NEXT WEAK SHORT WAVE WILL ARRIVE SATURDAY NIGHT COUPLED AGAIN WITH
ANOTHER COLD FRONT WHICH MAY AGAIN BRING IN SOME CONVECTION FROM
THE WEST. RIDGING ALOFT WILL QUICKLY FOLLOW THIS SHORT WAVE SO
PROSPECTS FOR CONVECTIVE DEVELOPMENT ARE LOW.
THE NEXT UPPER LEVEL SYSTEM WILL DROP DOWN THE CASCADES AND SIERRA
NEVADA RANGES INTO SOUTHERN ARIZONA ON SATURDAY AND SUNDAY. THIS
WILL CAUSE UPPER FLOW LOCALLY TO BACK TO THE SOUTHWEST AHEAD OF
THIS SYSTEM. THIS SYSTEM WILL WEAKEN AS IT MOVES OUT OF THE
SOUTHWESTERN US NEXT WEEK BUT BEST CHANCES FOR CONVECTION LOOK TO
BE SUNDAY AND MONDAY. LIFT WILL BE DRIVEN BY SHORT WAVES OUT AHEAD
OF THIS TROUGH AND MOIST ISENTROPIC ASCENT. WE WILL GENERALLY BE
UNDER COOL EASTERLY FLOW TO START OFF NEXT WEEK IN THE WAKE OF THE
COLD FRONT ON SATURDAY. THIS WILL ALSO KEEP TEMPERATURES
UNSEASONABLY COOL KEEPING PROSPECTS OF SEVERE STORMS LOW. AFTER
THIS SYSTEM EXITS...WE WILL BE UNDER UPPER LEVEL RIDGING FOR THE
MIDDLE PART OF NEXT WEEK. ALTHOUGH MODELS HAVE INDICATED THE
POTENTIAL FOR NORTHWEST FLOW STORMS IN THIS PATTERN.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
902 PM EDT SAT APR 30 2016
.SYNOPSIS...
HIGH PRESSURE TO THE NORTH WILL MAINTAIN A COOL WEDGE ACROSS THE
REGION OVERNIGHT AHEAD OF A WARM FRONT APPROACHING FROM THE SOUTH
LATE. THIS WARM FRONT WILL MOVE NORTH OF THE AREA SUNDAY
AFTERNOON...FOLLOWED BY A COLD FRONT MONDAY. A STRONGER COLD FRONT
WILL THEN MOVE THROUGH THE REGION BY MIDWEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 840 PM EDT SATURDAY...
DEEPER MOISTURE HAS CONTINUED TO SLOWLY INCREASE FROM SW TO NE
THIS EVENING AS BACKING ALOFT OVER THE WEDGE HAS RESULTED IN
PROGRESSIVELY WETTER SOUNDINGS PER PWATS NOW OVER AN INCH. HOWEVER
THE LOW LEVEL CAD REMAINS FIRMLY ENTRENCHED WITH THE EVENING RNK
RAOB SHOWING EASTERLY FLOW UP TO ABOVE 9H WHILE GUIDANCE INDICATES
LITTLE EROSION UNTIL LATE AND MAINLY ACROSS THE SW PERIMETER. THIS
WILL CONTINUE TO SUPPORT BANDS OF CONVECTION DEVELOPING TO THE
SOUTH WITHIN MORE INSTABILITY...AND THEN RIDING OVER THE COOL
POOL IN ELEVATED FASHION OVERNIGHT IN CONJUNCTION WITH MORE ISENTROPIC
LIFT NATURE LIGHT RAIN FARTHER NORTH. LATEST HRRR SUPPORTS THIS
TREND OVER THE NEXT FEW HOURS WITH ANY CONVECTION WEAKENING BEFORE
RAMPING UP DURING THE EARLY MORNING HOURS WHEN THE WARM FRONT TO
THE SOUTH GETS CLOSER AND MOISTURE CONVERGENCE ENHANCES. APPEARS
COULD BE A COUPLE ROUNDS OF HEAVIER SHOWERS WITH ISOLATED TSRA
POSSIBLE MAINLY SOUTH/WEST AS WARMING ALOFT DEEPENS A BIT BUT
STILL UNCERTAINTY WITH THE DEGREE OF ANY PROLONGED HEAVY RAIN.
THUS WONT HOIST ANY FLOOD WATCHES ESPCLY GIVEN LIGHTER TOTALS SO
FAR AND LITTLE OUT EAST WHERE THE DEEPER WEDGE CONTINUES TO LIMIT
PRECIP. OTRW HAVE AGAIN TRENDED POPS LOWER EAST OF THE BLUE RIDGE
TO INIT BEFORE INCREASING TO LIKELY/CATEGORICAL OVERNIGHT AS
DEEPER MOISTURE FINALLY NUDGES EAST. FOG ALSO REMAINS AN ISSUE
ALONG THE BLUE RIDGE BUT WITH RAIN INCREASING EXPECTING SOME
IMPROVEMENT FROM SW TO NE. THUS STAYING WITH THE GOING SPS FOR
AREAS OF DENSE FOG WITHOUT HEADLINES FOR NOW. LOWERED TEMPS A
LITTLE MORE GIVEN CONTINUED LOW LEVEL COOL ADVECTION AND LIGHT
RAIN/DRIZZLE THROUGH THE COLUMN WHICH HAS COOLED MOST BACK INTO
THE CHILLY/DAMP LOW/MID 50S THIS EVENING.
UPDATE AS OF 620 PM EDT SATURDAY...
WITH THE MAJORITY OF THE MEASURABLE RAINFALL MAINLY ACROSS THE FAR
NW AND EXTREME SW SECTIONS...UPDATED TO LOWER POPS BACK TO CHANCE
ELSEWHERE FOR A COUPLE HOURS INTO THIS EVENING. APPEARS MOST
SIGNIFICANT RAINFALL WILL OCCUR OVER THE NW NC MOUNTAINS/FOOTHILLS
WHERE CONVECTION DEVELOPING IN A MORE UNSTABLE ENVIRONMENT TO THE
SW PUSHES INTO/OVER THE WESTERN PERIPHERY OF THE WEDGE OVER THE
NEXT FEW HOURS. THIS WARM ADVECTION HAS ALSO CAUSED CLOUD BASES TO
LOWER ALLOWING FOR MORE WIDESPREAD DENSE FOG ALONG PARTS OF THE
SOUTHERN BLUE RIDGE. THIS TREND MAY DEVELOP FARTHER NORTH AS WARM
AIR ALOFT DEEPENS OVER THE WEDGE AND AIDED BY SATURATED LOW LEVELS
PER RAINFALL. ALSO LOWERING LOW TEMPS A FEW DEGREES MOST LOCATIONS
SINCE CLOSE TO CURRENT FORECAST VALUES OVERNIGHT ALTHOUGH NOT
EXPECTING VALUES TO FALL MUCH MORE AS RAINFALL INCREASES.
PREVIOUS DISCUSSION AS OF 330 PM EDT SATURDAY...
STRONG WEDGE IN PLACE THIS AFTERNOON WILL HOLD AS WE HEAD THRU THE
NIGHT. MEANWHILE...UPPER LEVEL DIVERGENCE AHEAD OF SHORTWAVE WILL
SET UP ACROSS THE CENTRAL AND SOUTHERN APPALACHIANS THIS EVENING
WITH RAINFALL OVERSPREADING THE MOUNTAINS. LOOKING AT OVERNIGHT WE
START TO SEE MODELS EMPHASIZE STRONG LOW LVL CONVERGENCE WITH UPPER
DIVERGENCE ACROSS THE SOUTHERN CWA...WITH ENHANCED RAINFALL AMOUNTS
IN THE SOUTHERN APPALACHIANS. ATTM...LOOKS LIKE AT LEAST MOST OF THE
AREA WILL SEE RAIN OVERNIGHT WITH ONE HALF TO THREE QUARTERS OF AN
INCH SETTING UP ACROSS THE SOUTHERN BLUE RIDGE. WILL NOT ISSUE A
FLOOD WATCH AT THIS POINT...BUT WILL BEAR MONITORING TO SEE IF ANY
DEEP CONVECTION DEVELOPS AND TRAINS ACROSS THIS AREA LATE TONIGHT.
WILL MAINTAIN ISOLATED FLOOD THREAT IN THE HWO.
AS FAR AS THUNDERSTORMS...AM KEEPING THEM OUT OF THE FORECAST
THROUGH TONIGHT GIVEN LACK OF INSTABILITY AND WEDGE. AS WE HEAD TO
SUNDAY WILL BE HARD PRESSED TO CLEAR SKIES IN THE NORTH AND EAST BUT
MODELS FAVOR QUICKER EROSION OF THE WEDGE. WILL BE SLOWER...THEN
INTRODUCE A CHANCE OF STORMS IN THE AFTERNOON. SPC CONTINUES TO
HIGHLIGHT MARGINAL RISK FOR MOST OF THE CENTRAL AND SOUTHERN
APPALACHIANS INTO THE PIEDMONTS OF NC/VA. QUESTION WILL BE IF
SUNSHINE CAN BREAK OUT. AT THE MOMENT SEEMS BEST CHANCE OF THIS WILL
BE IN WV/FAR SW VA AND ACROSS THE NW NC PIEDMONT...BUT THINK CLOUDS
WILL BE AROUND MOST OF THE DAY.
WITH FLOW TURNING SSW BY AFTERNOON WENT CLOSE TO MOS ON HIGHS...BUT
COULD SEE IT COOLER IN LYH TO HSP. MOST WILL SEE HIGHS IN THE LOWER
TO MID 70S.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 230 PM EDT SATURDAY...
A WEAK WAVE OF LOW PRESSURE WILL BE TRACKING NORTHEAST FROM THE OHIO
VALLEY TOWARD NEW ENGLAND OVERNIGHT SUNDAY DRAGGING A COLD FRONT
SLOWLY ACROSS THE REGION EARLY MONDAY. CHANCES FOR SHOWERS OVERNIGHT
WILL BE DECREASING DURING THE DAY AND SHOULD SEE SOME PARTIAL
CLEARING ESPECIALLY EAST OF THE MOUNTAINS LATER IN THE DAY. EXPECT
MILD TEMPS BEHIND THE FRONT ON MONDAY RANGING FROM NEAR 70 NORTHWEST
TO LOW 80S SOUTHEAST AS COOLING IS MODEST BEHIND IT..H85 TEMPS
DROPPING ONLY A FEW DEGREES BY LATE IN THE DAY. THIS BOUNDARY MAKES
ONLY SLIGHT PROGRESS TO THE SOUTHEAST BY LATE MONDAY LEAVING ENOUGH
CLOUDS TO HOLD TEMPS UP SOMEWHAT HIGHER MONDAY NIGHT...GENERALLY
UPPER 40S TO MID-50S. THE SAME FRONT WILL BECOME NEAR STATIONARY
ALONG COAST AND BECOME THE FOCUS FOR SHOWERS AND POSSIBLY SOME
THUNDERSTORMS ON TUESDAY AS SEVERAL WEAK WAVES TRAVERSE NORTHEAST
ALONG IT. MODELS DIFFER IN THE PLACEMENT OF THIS BOUNDARY STRENGTH
OF PERTURBATIONS ALONG IT WHICH WILL HAVE A SUBSTANTIAL IMPACT ON
PRECIPITATION CHANCES ON TUESDAY. WPC AND GFS SOLUTIONS CURRENTLY
FURTHER SOUTHEAST THAN EARLIER CMC OR ECMWF RUNS WHICH BOTH BRING
CONSIDERABLY MORE CLOUDS AND SHOWERS INTO OUR CWA. WENT WITH A MODEL
BLEND RETAINING CHANCE POPS ACROSS THE ENTIRE CWA BUT THE HIGHEST
OVER THE SOUTHEAST.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 230 PM EST SATURDAY...
LOW PRESSURE WILL CONTINUE TO LINGER ALONG THE SOUTHEAST COAST EARLY
WEDNESDAY WITH ASSOCIATED CLOUDS AND SHOWERS MAINLY CONFINED TO THE
COASTAL PLAIN AND EASTERN PIEDMONT DURING THE DAY BUT STILL
LINGERING POPS ACROSS OUR CWA BUT MAINLY SOUTHEAST. TEMPS WILL
REMAIN NEAR SEASONAL LEVELS WEDNESDAY WITH PARTIAL CLEARING DURING
IN THE DAY ESPECIALLY NORTHWEST. MEANWHILE ANOTHER FRONT OVER THE
UPPER PLAINS BEGINS TO DROP SOUTHEAST TOWARD THE AREA LATE WEDNESDAY
INTO THURSDAY AS NORTHERN STREAM TROUGH BEGINS TO AMPLIFY
SHARPLY.BOTH GFS AND EURO SHOW UPPER LOW CLOSING OVER THE EASTERN
CONUS BY LATE THURSDAY WITH EXACT POSITION UNCERTAIN AND LIKELY TO
HAVE CONSEQUENCES FOR SENSIBLE WEATHER BY THAT TIME. 00Z EURO IS THE
MOST AGGRESSIVE WITH DEEP COMPLEX SURFACE LOW MORE OR LESS MERGING
WITH THE EXISTING COASTAL SYSTEM AND ACTUALLY BACKING IN TOWARD THE
MID-ATLANTIC COAST. GFS/CMC NOT QUITE AS FAR SOUTH AND DEEP WITH
UPPER TROUGH AND SURFACE REFLECTION WHICH SEEMS MORE
CLIMATOLOGICALLY PLAUSIBLE BUT WENT WITH BLEND TO ACCOUNT FOR
SIGNIFICANT UNCERTAINTY. EITHER WAY A PERSISTENT DEEP NORTHWEST FLOW
WILL EXIST FRIDAY INTO SATURDAY WITH COOL TEMPS AND PLENTY OF CLOUDS
ESPECIALLY ACROSS THE MOUNTAINS. HIGHS FRIDAY WILL STRUGGLE TO REACH
60 OVER THE MOUNTAINS...CLOSE TO 10F BELOW NORMAL. SLOWLY RISING
HEIGHTS SATURDAY WILL ALLOW FOR SLOWLY IMPROVING CONDITIONS.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
AS OF 740 PM EDT SATURDAY...
SURFACE WEDGE WILL CONTINUE TO HOLD FAST IN THE EASTERN PART OF
THE REGION OVERNIGHT. LOW LEVEL WINDS WILL CONTINUE TO INCREASE IN
ADVANCE OF AN APPROACHING SYSTEM. MOISTURE ADVECTION WILL BE
STRONG WITHIN THESE WINDS. EXPECT LIGHT PRECIPITATION TO INCREASE
ACROSS THE REGION FROM WEST TO EAST DURING THE OVERNIGHT
HOURS...WITH COVERAGE GREATEST IN THE WEST. CIGS WILL LOWER TO
INTO THE LIFR/IFR RANGE WITH VSBYS MAINLY IFR/MVFR. THE STRONG LOW
LEVEL WINDS ABOVE THE WEDGE WILL ALLOW FOR A FEW HOURS OF LOW
LEVEL WIND SHEAR LATE TONIGHT INTO EARLY SUNDAY MORNING.
RAIN WILL CONTINUE ACROSS THE REGION SUNDAY MORNING...WITH ONLY
MINOR IMPROVEMENTS TO FLIGHT CATEGORIES. THE PRECIPITATION WILL
START TO BECOME MORE SHOWERY IN THE WEST BY THE LATE MORNING.
CIGS/VSBYS IMPROVING TO MVFR/VFR BY SUNDAY AFTERNOON AS THE WEDGE
ERODES. SUNDAY AFTERNOON BRINGS THE POTENTIAL FOR SCATTERED
CONVECTION...SOME POSSIBLY STRONG TO SEVERE AS SHORT WAVE ENERGY
TRACKS NORTHEAST ACROSS THE REGION IN THE WARM/UNSTABLE AIR MASS.
SITUATION APPEARS SOMEWHAT SIMILAR TO WHAT WAS OBSERVED THURSDAY
ACROSS THE REGION...BUT PERHAPS MORE ACTIVITY NORTH-WEST OF THE
BLUE RIDGE THIS TIME AROUND THAN WHAT WAS OBSERVED SUNDAY.
EXTENDED AVIATION DISCUSSION...
SFC LOW PRESSURE TRACKS NORTHEAST ACROSS GA/SC/NC SUN NIGHT-
TUE...LIKELY PROLONGING SUB-VFR CIGS AND POTENTIALLY LEAVING SOME
LIGHT PRECIPITATION ACROSS THE REGION...ESPECIALLY EAST OF THE
BLUE RIDGE. FOR THE MID AND LATER PART OF NEXT WEEK...A DEEP UPPER
LOW IS EXPECTED TO DROP DOWN ACROSS THE GREAT LAKES INTO THE
APPALACHIANS AND MID-ATLANTIC REGION...WHICH WILL LEAVE THE REGION
WITH VARIABLE CLOUDINESS...SHOWERS...AND PERIODS OF SUB-VFR
CONDITIONS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/WP
SHORT TERM...PC
LONG TERM...PC
AVIATION...DS/WP
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 239 PM CDT FRI APR 29 2016
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW UPPER LEVEL
LOW PRESSURE MOVING EAST OVER THE EASTERN GREAT LAKES. BEHIND THE
SYSTEM...SCATTERED TO BROKEN CLOUDS EXIST OVER MUCH OF LOWER
MICHIGAN AND WISCONSIN. SOME CLEARING DOES EXIST OVER EASTERN UPPER
MICHIGAN...AND THINK SOME OF THIS DRIER AIR WILL TRY TO MAKE INROADS
INTO NORTHEAST WISCONSIN LATER THIS AFTERNOON. MEANWHILE...ANOTHER
LOW PRESSURE SYSTEM IS MOVING EAST OVER THE SOUTHERN PLAINS. CLOUD
TRENDS AND SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERNS IN
THE SHORT TERM.
TONIGHT...HUDSON BAY HIGH PRESSURE WILL BE BUILDING SOUTHWARD OVER
THE NORTHERN GREAT LAKES WHILE LOW PRESSURE WILL BE MOVING NORTHEAST
OVER THE CENTRAL GREAT PLAINS. SCATTERED TO BROKEN CLOUD COVER WILL
LIKELY PERSIST INTO MID-EVENING OVER PARTS OF CENTRAL AND NORTH-
CENTRAL WI. THINK THAT DRY AIR WILL EVENTUALLY MAKE PROGRESS THOUGH
TO CREATE A PERIOD OF MOSTLY CLEAR CONDITIONS ACROSS THE REGION. AS
LOW LEVEL EASTERLY WINDS STRENGTHEN...HOWEVER...CLOUDS OVER LOWER
MICHIGAN WILL LIKELY GET RECYCLED WESTWARD OVER EAST-CENTRAL AND
CENTRAL WI LATE TONIGHT. BECAUSE OF A TIGHTER PRESSURE GRADIENT AND
CLOUD COVER IN THIS AREA...THINK A WIDESPREAD FROST IS NOT LIKELY
DESPITE TEMPS FALLING INTO THE MID 30S.
SATURDAY...LOW PRESSURE WILL MOVE EAST TOWARDS CENTRAL ILLINOIS.
SIMILAR TO THE SYSTEM WE SAW A COUPLE DAYS AGO...AN ARCING BAND OF
RAIN WILL BE LIFTING NORTHWARD OVER THE COURSE OF THE DAY. DRY AIR
ORIGINATING OUT OF THE HUDSON BAY HIGH WILL SLOW THE FORWARD
PROGRESS OF THE PRECIP...BUT WILL HAVE A SMALL CHANCE OVER THE
SOUTHERN FOX VALLEY AND PARTS OF CENTRAL WI LATE IN THE AFTERNOON.
OVER NORTHERN WI...WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY
CONDITIONS. HIGH TEMPS WILL RANGE FROM MID 50S TO AROUND 60 ACROSS
THE REGION.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 239 PM CDT FRI APR 29 2016
LOW PRESSURE SLATED TO TRACK TO OUR SOUTH SATURDAY NIGHT HAS
JOGGED A BIT FURTHER NORTH WITH THIS SET OF NWP RUNS...WITH THE
SURFACE LOW TRACKING NORTH OF THE OHIO VALLEY INSTEAD OF THROUGH
THE OHIO VALLEY ITSELF. THIS WILL BRING THE RAIN SHIELD A BIT
FURTHER NORTH THAN PREVIOUSLY FORECAST...HOWEVER DESPITE THE
NORTHWARD JOG MOST OF THE CWA NORTH OF HIGHWAY 29 IS EXPECTED TO
REMAIN DRY AS NORTHERLY WINDS FROM A HIGH ANCHORED ACROSS SOUTHERN
CANADA PUMP IN DRY AIR. THEREFORE WILL RAISE POPS SATURDAY NIGHT
ACROSS THE EXTREME SOUTHERN CWA AND TIGHTEN UP THE POP GRADIENT AS
RAIN IS EXPECTED TO MAINLY STAY ACROSS THE SOUTH DESPITE THE
NORTHWARD JOG OF THE LOW.
THE HIGH TO THE NORTH WILL THEN ESTABLISH ITSELF ACROSS THE GREAT
LAKES...KEEPING THE REGION DRY DURING THE SECOND HALF OF THE
WEEKEND AND INTO THE EARLY PART OF NEXT WEEK.
THE MODELS THEN COME BETTER IN LINE WITH A DEVELOPING LOW SLATED
TO TRACK THROUGH THE GREAT LAKES DURING THE MIDDLE OF NEXT
WEEK...BRINGING THE CHANCE FOR RAIN AND A COLD FRONT THROUGH THE
WESTERN GREAT LAKES REGION SOMETIME BETWEEN TUESDAY AND WEDNESDAY.
ALTHOUGH INDICATIONS ARE THAT THE MODELS ARE BETTER IN
LINE...THERE ARE STILL DIFFERENCES BETWEEN THE MODELS THEMSELVES
REGARDING THIS SYSTEM. THEREFORE WILL CONTINUE TO MAINTAIN CHANCY
POPS DURING THIS PERIOD FOR THIS SYSTEM.
LATER IN THE WEEK THE ECMWF AND CANADIAN MODELS KEEP THE REGION
DRY AS HIGH PRESSURE ONCE AGAIN BECOMES ESTABLISHED ACROSS THE
GREAT LAKES REGION. IN STARK CONTRAST THE GFS PRODUCES WHAT LOOKS
LIKE A CONVECTIVELY INDUCED LOW WITH SUBSTANTIAL QPF ACROSS THE
WESTERN GREAT LAKES THURSDAY NIGHT. GIVEN THE ANOMALOUS APPEARANCE
OF THIS LOW AND ASSOCIATED QPF FIELD WILL NOT LEND MUCH CREDENCETO
THIS SYSTEM LATE IN THE EXTENDED.
TEMPERATURES DURING THE EXTENDED WILL GENERALLY BE AROUND
NORMAL...WITH TUESDAY GETTING ABOVE NORMAL WELL INTO THE 60S AHEAD
OF THE APPROACHING COLD FRONT IN THE MIDDLE OF THE WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1207 PM CDT FRI APR 29 2016
SCATTERED TO BROKEN CLOUD COVER WILL CONTINUE ACROSS THE
TAF SITES THROUGH THE AFTERNOON HOURS. CIGS WILL GRADUALLY RISE
THROUGH THE DAY...ENDING ANY MVFR CIGS OVER CENTRAL WI BY EARLY THIS
AFTERNOON. CLOUDS ARE ANTICIPATED TO CLEAR AT MOST LOCATIONS THIS
EVENING FOR A TIME...THEN SOME MODELS ARE INDICATING THAT CLOUDS
WILL GET RECYCLED WEST INTO EAST-CENTRAL WI LATE TONIGHT INTO
SATURDAY MORNING. ANY CLOUDS LOOK TO REMAIN VFR THOUGH SOME
MVFR CIGS NOT OUT OF THE QUESTION.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KURIMSKI
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
413 AM EDT SUN MAY 1 2016
.SYNOPSIS...
LOW PRESSURE WILL PASS FAR TO THE NORTH TODAY AND MONDAY. ANOTHER
AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP JUST NORTH OF THE AREA
TUESDAY AND WEDNESDAY. HIGH PRESSURE WILL BUILD INTO THE REGION BY
THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
THROUGH SUNRISE...APPROACHING SHORTWAVE ENERGY HAS BEEN ABLE TO
SPARK OFF ISOLATED TO SCATTERED SHOWERS AND TSTMS ACROSS PARTS OF
SOUTHEAST GEORGIA THIS MORNING. INSTABILITY IS MODEST FOR EARLY
MORNING HOURS PER RAP SOUNDINGS AND MSAS INSTABILITY FIELDS, SO
THE RISK FOR TSTMS WILL CONTINUE. ISOLATED TO PERHAPS SCATTERED
CONVECTION WILL GRADUALLY SPREAD NORTHEAST THROUGH DAYBREAK AS
SHORTWAVE ENERGY TRAVERSES THE AREA. WILL SHOW AN AREA OF 20-30
GRIDDED POPS MOVING NORTHEAST ACROSS ALL OF SOUTHERN SOUTH
CAROLINA AND SOUTHEAST GEORGIA COINCIDENT WITH THE SHORTWAVE FOR
THE NEXT SEVERAL HOURS. THE RISK FOR MEASURABLE RAINFALL SHOULD
END BY SUNRISE AS SUBSIDENCE DEVELOPS AS THE SHORTWAVE EXITS TO
THE NORTHEAST.
TODAY...UPPER RIDGING WILL CONTINUE TO ERODE AND SHIFT FARTHER
OFFSHORE TODAY IN RESPONSE TO A STRONG SHORTWAVE KICKING OUT OF
THE CENTRAL PLAINS AND ANOTHER LOW CUTTING OFF OVER THE FOUR
CORNERS REGION. AFTER SEVERAL DAYS OF DRY WEATHER, TODAY IS
LOOKING INCREASINGLY ACTIVE FOR SHOWERS/TSTMS AS ANOTHER POTENT
SOUTHERN STREAM SHORTWAVE APPROACHES AND INTERACTS WITH MODERATE
INSTABILITY ACROSS THE SOUTHEAST STATES. MOST OF THE MORNING LOOKS
DRY AS SUBSIDENCE DOMINATES IN THE WAKE OF EXITING SHORTWAVE
ENERGY, BUT THIS WILL CHANGE BY EARLY AFTERNOON AS INFERRED
CYCLONIC VORTICITY ADVECTION AHEAD OF THE DOWNSTREAM SHORTWAVE AND
UPPER DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF AN
APPROACHING SUBTROPICAL JET STREAM SPREAD IN FROM THE SOUTHWEST.
THE MOST FAVORABLE ALIGNMENT OF LOW-LEVEL CONVERGENCE, UPPER
FORCING AND INSTABILITY LOOKS TO SETTLE INTO THE AREA NORTH OF
I-16 AND WEST OF I-95 BY EARLY-MID AFTERNOON. POPS WILL BE
INCREASED TO 50 PERCENT IN THIS REGION WITH 20-40 PERCENT POPS
ELSEWHERE--LOWEST ALONG THE BEACHES.
WATER VAPOR IMAGERY SHOWS A DRY SLOT QUICKLY APPROACHING FROM THE
WEST WHICH IS ON TARGET TO OVERSPREAD THE AREA LATER THIS
MORNING. THIS WILL SUPPORT MODERATE BREAKS IN THE CLOUD CANOPY, SO
TEMPERATURES WILL ONCE AGAIN WARM INTO THE MID-UPPER 80S WITH A
FEW ISOLATED INSTANCES OF 90 OCCURRING ACROSS INTERIOR SOUTHEAST
GEORGIA WHERE THE BREAKS WILL BE THE MOST PREVALENT THIS MORNING.
SIMILAR TO SATURDAY, A STRONGER ONSHORE FLOW ACROSS THE CENTRAL
SOUTH CAROLINA COAST WILL SUPPORT COOLER/MORE STABLE CONDITIONS
ACROSS MUCH OF CHARLESTON COUNTY WHERE HIGHS WILL ONLY WARM INTO
THE LOWER 80S AWAY FROM THE BEACHES.
MODIFIED SOUNDINGS DEPICT MODERATE INSTABILITY BY EARLY AFTERNOON
WITH SBCAPE REACHING AS HIGH AS 2500 J/KG INLAND AND LIFTED
INDICES AS LOW AS -6C. THERE IS QUITE A BIT OF 0-3KM CAPE NOTED
WEST OF THE I-95 CORRIDOR WHICH SUGGESTS STORMS COULD GO UP WITH
SOME FEROCITY ONCE INITIATION OCCURS. THE APPROACHING DRY SLOT
WILL SUPPORT A RISK FOR DAMAGING WINDS WITH DCAPE VALUES REACHING
AS HIGH AS 900-1200 J/KG. HIGH CAPE VALUES IN THE -10 TO -30C
LAYER AND WBZ HEIGHTS JUST ABOVE 10 KFT WILL ALSO SUPPORT A RISK
FOR MARGINALLY SEVERE HAIL. DESPITE STRONG INSTABILITY, WEAK SHEAR
PROFILES OF 15-25 KT SUGGEST THE FORMATION OF ANY ORGANIZED SEVERE
WEATHER IS LOW. HOWEVER, ISOLATED SEVERE THUNDERSTORMS WILL BE
POSSIBLE, ESPECIALLY WHERE LOW-LEVEL FORCING IS SUPPLEMENTED BY
MESOSCALE BOUNDARY COLLISIONS. THE RISK FOR SEVERE THUNDERSTORMS
WILL BE THE GREATEST NORTH OF I-16 AND WEST OF I-95 AND WILL BE
HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
TONIGHT...CONVECTION WILL GRADUALLY WIND DOWN DURING THE EARLY
EVENING AS INSTABILITY WANES AND SHORTWAVE ENERGY PUSHES OFF TO
THE NORTHEAST AWAY FROM THE AREA. COULD SEE AN ISOLATED SHOWER
BRUSH THE CENTRAL/UPPER CHARLESTON COUNTY COAST EARLY MONDAY
MORNING AS NOCTURNAL SHOWER/TSTM ACTIVITY DEVELOPS OVER THE
COASTAL WATERS, BUT CONFIDENCE IN THIS SCENARIO IS STILL RATHER
LOW. IT WILL BE ANOTHER WARM/HUMID NIGHT WITH LOWS ONLY DROPPING
INTO THE UPPER 60S INLAND TO THE LOWER 70S AT THE COAST.
MONDAY...AN UNSETTLED PATTERN EXPECTED THROUGH THIS PERIOD. A
BROAD...POSITIVELY TILTED UPPER LEVEL TROUGH...WILL REMAIN OVER
THE NORTH- CENTRAL PORTION OF THE COUNTRY. THIS WILL KEEP OUR
REGION ON THE SOUTHEAST PERIPHERY OF THE UPPER TROUGH...WITH
PERIODIC WEAK UPPER IMPULSES EXPECTED TO MOVE ACROSS THE REGION
MONDAY. GIVEN THE WEAKNESS OF THE UPPER FEATURES...TIMING OF
CONVECTION IS CHALLENGING. MONDAY STARTS OUT DRY WITH POPS
INCREASING TO CHANCE FROM WEST TO EAST AS THE DAY PROGRESSES. THE
BEST CHANCES WILL BE DURING THE AFTERNOON COINCIDENT WITH MAXIMUM
HEATING. CAPE VALUES ARE MODERATE IN THE 1000-1500 J/KG
RANGE...BUT WEAK BULK SHEARS WILL MEAN ANY THUNDERSTORM ACTIVITY
SHOULD REMAIN BELOW SEVERE LIMITS AND LACK ORGANIZATION. THE
MODELS STILL INDICATE HIGH POPS MONDAY NIGHT. THIS SEEMS TO BE A
LITTLE OVERDONE GIVEN THE LOCATION OF THE SYNOPTIC FEATURES. KEPT
CHANCE POPS...BUT HAVE THEM TRENDING DOWNWARD AS THE NIGHT
PROGRESSES.
TUESDAY...THE TROUGH REMAINS OVER THE EAST COAST WHILE A SHORT WAVE
ROUNDS THE BASE OF THE TROUGH DURING THE DAY...MOVING INTO THE
MIDDLE MISSISSIPPI VALLEY. AT THE SURFACE...A BROAD AREA OF WEAK LOW
PRESSURE WILL BE SPREAD ACROSS THE MID-ATLANTIC STATES WITH A COLD
FRONT STRETCHED DOWN NEAR THE FLORIDA PANHANDLE. OUR AREA WILL BE IN
THE WARM/UNSTABLE SECTOR OF THE SYNOPTIC PATTERN.
PLENTIFUL MOISTURE ACROSS THE AREA...PWATS EXCEEDING 1.5
INCHES...COMBINED WITH GOOD LIFT DUE TO THE TROUGH AND THE
APPROACHING COLD FRONT WILL LEAD TO SHOWERS AND THUNDERSTORMS.
RAISED POPS TO ACCOUNT FOR THIS. THE INGREDIENTS ARE COMING TOGETHER
FOR SOME OF THESE STORMS TO BE STRONG OR MAYBE SEVERE.
ALONG WITH THE AFOREMENTIONED LIFT AND MOISTURE THERE WILL BE A JET
STREAK APPROACHING FROM THE WEST. THERE WILL ALSO BE PLENTY OF
INSTABILITY AT THE SURFACE. THE QUESTION IS DO ALL OF THE
INGREDIENTS COME TOGETHER AT THE RIGHT TIME? IF THEY DO THEN THE
GREATEST THREAT WOULD BE DAMAGING WINDS AND HAIL. GIVEN THERE IS
STILL SOME UNCERTAINTY IN THE FEATURES COMING TOGETHER AT THE RIGHT
TIME...ESPECIALLY THE COLD FRONT WHICH MAY CROSS THROUGH THE AREA
TUESDAY NIGHT. WE STILL DO NOT HAVE SEVERE IN THE FORECAST AND ARE
HIGHLIGHTING IT IN THE HWO. THIS WILL BE UPDATED IN THE UPCOMING
FORECAST PACKAGES.
WEDNESDAY...THE TROUGH IS STILL OVER THE EAST COAST WHILE THE SHORT
WAVE ROUNDS THE EASTERN PERIPHERY OF IT...MOVING INTO THE MID-
ATLANTIC STATES. AT THE SURFACE A COLD FRONT WILL BE JUST OFFSHORE
IN THE MORNING...MOVING AWAY DURING THE DAY. SOME REMNANT LIGHT
SHOWERS ARE POSSIBLE...ESPECIALLY IN THE MORNING. POPS WILL
GRADUALLY DECREASE DURING THE DAY AS HIGH PRESSURE BUILDS INTO THE
REGION...ALLOWING FOR DRYING CONDITIONS. HIGH WILL BE A FEW DEGREES
BELOW NORMAL...IN THE UPPER 70S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
MODELS ARE NOW IN FAIRLY GOOD AGREEMENT SHOWING WEAK HIGH PRESSURE
OVER THE AREA WEDNESDAY NIGHT WHILE A STORM SYSTEM IMPACTS THE
NORTHEASTERN STATES. A DRY COLD FRONT IS FORECAST TO MOVE THROUGH ON
THURSDAY...BRINGING COOLER TEMPERATURES FOR FRIDAY. DESPITE A TROUGH
REMAINING OVER THE EAST COAST DURING THIS ENTIRE TIME PERIOD...POPS
ARE LOW BECAUSE HIGH PRESSURE WILL BE SPREAD ACROSS OR NEAR THE
SOUTHEAST STATES FRIDAY AND SATURDAY.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
BEST CHANCES FOR MVFR CIGS PRIOR TO SUNRISE WILL BE AT KCHS. RIGHT
NOW...CONDITIONS DO NOT FAVOR SIGNIFICANT STRATUS BUILD DOWN SO
CIGS ARE NOT EXPECTED TO DROP TO IFR THERE. WILL CARRY PREVAILING
MVFR CIGS 08-12Z. AT KSAV...EXPECT MAINLY VFR NEXT FEW HOURS WITH
MARGINAL MVFR CIGS POSSIBLE JUST BEFORE SUNRISE. WILL GO A TEMPO
GROUP FROM 09-12Z TO COVER THIS. OTHERWISE...VFR TODAY. BEST
CHANCES FOR SHOWERS/TSTMS WILL REMAIN WEST OF THE TERMINALS. WILL
NOT CARRY A MENTION OF TSRA OR SHRA FOR THE 06Z TAF CYCLE.
EXTENDED AVIATION OUTLOOK...PERIODIC FLIGHT RESTRICTIONS WITHIN
SCATTERED SHOWERS/THUNDERSTORMS...MONDAY THROUGH TUESDAY NIGHT.
&&
.MARINE...
TODAY AND TONIGHT...A SOUTHERLY FLOW WILL PERSIST TODAY AS HIGH
PRESSURE REMAINS WELL OFFSHORE. WINDS WILL REMAIN AROUND 10 KT
WITH SEAS 2-4 FT THROUGH THE PERIOD.
MONDAY THROUGH THURSDAY...NO HIGHLIGHTS ARE EXPECTED THROUGH THE
PERIOD. IN GENERAL...THE WATERS WILL SIT BETWEEN ATLANTIC HIGH
PRESSURE WELL ENE OF THE AREA AND LOWER PRESSURE OVER THE MID
ATLANTIC AND CAROLINAS. THIS WILL RESULT IN SOUTH-SOUTHWEST WINDS
OF 15 KNOTS OR LESS AND SEAS 3 FEET OR LESS. UNSETTLE CONDITIONS
ARE LIKELY WITH SCATTERED SHOWER AND THUNDERSTORMS...ESPECIALLY
MONDAY AND TUESDAY.
&&
.EQUIPMENT...
THE CHARLESTON HARBOR NOS TIDE GAUGE HAS STOPPED REPORTING ALL
METEOROLOGICAL AND TIDE DATA. THE NATIONAL OCEAN SERVICE IS
INVESTIGATING THE CAUSE OF THE OUTAGE. AN ESTIMATED TIME FOR DATA
RESTORATION IS UNKNOWN AT THIS TIME.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST/MS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
1241 AM CDT SUN MAY 1 2016
.UPDATE...
746 PM CDT
STEADIER RAIN CONTINUES TO LIFT NORTH OF THE CWA THIS
EVENING...WITH ADDITIONAL SHOWERY DEVELOPMENT OR DRIZZLE STILL
LINGERING OVER MUCH OF THE CWA. WHILE LARGE SCALE ASCENT WILL
REMAIN PRESENT THIS EVENING/OVERNIGHT WITH THE UPPER LEVEL SYSTEM
JUST TO THE WEST...ISENTROPIC ASCENT WILL LIKELY AID IN EITHER
LIGHT RAIN OR DRIZZLE FOR MUCH OF THE CWA. SO HAVE MAINTAINED
CAT/LIKELY POPS THIS EVENING AND THEN LOWER TO CHANCE WORDING
AFTER MIDNIGHT. HAVE MADE LITTLE CHANGES TO LOW TEMPS
TONIGHT...WITH TEMPS EITHER HOLDING NEARLY STEADY OR SHOWING A
SLIGHT WARMING TREND.
RODRIGUEZ
&&
.SHORT TERM...
146 PM CDT
THROUGH SUNDAY...
COOL/CLOUDY/MOIST AIRMASS CONTINUES TO LIFT NORTH ACROSS NORTHERN
IL/NORTHWEST IN THIS AFTERNOON. IR IMAGERY HAD INITIALLY INDICATED
CLOUD TOPS WERE BETWEEN -60 TO -65 DEG C...BUT OVER THE PAST FEW
HOURS CLOUDS HAVE BEEN QUICKLY WARMING WITH TOPS NOW BETWEEN -50
TO -55 DEG C. IN ADDITION A WEDGE OF DRIER AIR CONTINUES TO LIFT
NORTHEAST AS THE AREA OF LOW PRESSURE MOVES INTO SOUTH CENTRAL IOWA
THIS AFTERNOON. THE PRESSURE GRADIENT HAS ARRIVED OVER NORTHERN IL
THIS AFTERNOON WITH EASTERLY WINDS INCREASING TO BETWEEN 10-15KT
AND GUSTS AROUND 20KT. THE LOW WILL BEGIN TO WEAKEN THIS
EVENING...BUT WITH A BROAD RIDGE POSITIONED OVER ONTARIO IT IS
LIKELY THAT THE LOW WILL STALL FROM LIFTING NORTHEAST OVERNIGHT.
THIS WILL SET THE STAGE FOR STEADIER PRECIP TO SHIFT NORTH AND END
LATE THIS AFTERNOON FROM SOUTH TO NORTH...WITH JUST A FEW
LINGERING SHOWERS THROUGH THE OVERNIGHT. THE BAGGY ATMOSPHERE WILL
CONTINUE TO SEE SHALLOW MOISTURE FEED ACROSS THE REGION...WITH
CONSIDERABLY LOWER CEILINGS OVERNIGHT. THE LACK OF A LIFT WILL
KEEP DROPLET SIZE MINIMAL AND LIKELY LEAD TO PATCHY DRIZZLE/LGT
RAIN. TEMPS OVERNIGHT WILL LIKELY NOT CHANGE MUCH...WITH LOWS IN
THE 40S.
WITH THE BROAD SFC RIDGE DISPLACED TO THE NORTH...THIS WILL KEEP
THE WARM FRONTAL BOUNDARY FROM LIFTING TOO FAR NORTH TOWARDS THE
CWFA OVERNIGHT INTO SUNDAY...HOWEVER THE 500MB VORT MAX WILL BE
UPSTREAM ACROSS SOUTHWEST IOWA TO STAR THE DAY SUNDAY. AS THIS
FEATURE PIVOTS NORTHEAST ACROSS NORTHERN IL...FORCING WILL RETURN
WITH INCREASED CHANCES FOR SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORM SOUTH OF I-80 SUNDAY AFTERNOON. THE NORTHEAST FLOW
OFF OF LAKE MICHIGAN WILL LIKELY KEEP TEMPS AGAIN SUN AFTN IN THE
40S FOR AREAS ADJACENT TO THE LAKE...MEANWHILE FURTHER INLAND
TEMPS SHOULD BE ABLE TO WARM INTO THE LOW/MID 50S. ACROSS THE
SOUTHERN CWFA THE WARM FRONTAL BOUNDARY WILL BE LINGERING NEARBY
WITH TEMPS NEARING THE LOW 60S.
BEACHLER
&&
.LONG TERM...
243 PM CDT
SUNDAY NIGHT THROUGH SATURDAY...
MAIN CONCERN GOING INTO THE LONGER TERM FORECAST PERIOD WILL BE THE
TEMPERATURE TREND THROUGH THE PERIOD. BY SUNDAY NIGHT...ANY
LINGERING PCPN ASSOCIATED WITH THE SYSTEM CURRENTLY BRINGING RAIN TO
NRN IL/NWRN IN WILL COME TO AN END FROM WEST TO EAST AS THE MAIN
SHORTWAVE SHIFTS TO THE ERN GREAT LAKES. A SERIES OF WEAK
SHORTWAVES IS EXPECTED TO DROP OUT OF THE NRN PLAINS AND ACROSS THE
UPPER MIDWEST EARLY NEXT WEAK...BUT AS HIGH PRESSURE BUILDS FROM THE
CENTRAL PLAINS THROUGH THE GREAT LAKES...AN EXTENDED PERIOD OF
GENERALLY NELY FLOW WILL KEEP MOISTURE ACROSS THE REGION VERY
LIMITED AND BY THE TIME A WEAK ASSOCIATED SFC FRONT MOVES THROUGH
THE AREA...ANY CHANCES FOR PCPN WILL BE MINIMAL AND...FOR NOW...WILL
ONLY CARRY SOME SLIGHT CHANCE POPS FOR THE FAR SERN PORTIONS OF THE
CWA ON MONDAY. ALSO BY EARLY NEXT WEEK...THE UPPER LEVEL PATTERN IS
EXPECTED TO UNDERGO SIGNIFICANT AMPLIFICATION...WITH STRONG RIDGING
BUILDING OVER THE WRN CONUS AND DEEP LONG WAVE TROUGHING DEVELOPING
OVER THE ERN CONUS. WHILE THE LONGER RANGE GUIDANCE IS RELATIVELY
CONSISTENT ON THE GENERAL SCENARIO...THERE ARE SIGNIFICANT ENOUGH
DIFFERENCES IN THE FINER SCALE DETAILS...IN PARTICULAR THE SPEED OF
PROGRESSION OF THE LONG WAVE PATTERN. CONSEQUENTLY...THE TRACK OF
SHORT WAVE ENERGY DROPPING SEWD DOWN THE ERN PERIPHERY OF THE UPPER
RIDGE IS DIFFERENT ENOUGH THAT THE DEGREE OF CONFIDENCE IN THE
LONGER TERM FORECAST RAPIDLY DETERIORATES WITH TIME FROM TUESDAY
THROUGH THE END OF THE WEEK. SO...IN GENERAL...EXPECT A PERIOD OF
CHANGEABLE WEATHER FOR THE MIDDLE AND LATTER PORTIONS OF NEXT
WEAK...ESPECIALLY TEMPERATURES. WHILE THERE SHOULD BE PERIODS OF
SEASONABLE AND BELOW NORMAL TEMPERATURES THROUGH THE WEEK...
CONFIDENCE IN THE TIMING IS LOW.
KREIN
&&
.AVIATION...
FOR THE 06Z TAFS...
06Z TAF CONCERNS ARE PRIMARILY
-PROLONGED PERIOD OF LIFR CIGS OVERNIGHT.
-IFR VSBY IN DZ/BR AT TIMES INTO SUNDAY MORNING.
-PERIOD OF SHRA SUNDAY EVENING WITH LOWER CIGS.
EXTENSIVE AREA OF IFR/LIFR CIGS OF 300-700 FT HAVE DEVELOPED
ACROSS ALL OF NORTHERN IL AND NORTHWEST INDIANA LATE THIS EVENING.
OBS TRENDS INDICATE FURTHER LOWERING INTO SOLID LIFR 300-400 FT
LIKELY FOR ALL TAF SITES NEXT FEW HOURS WITH PERSISTENT DRIZZLE
INTO SATURATED AIR MASS NORTH OF LOW PRESSURE TRACKING ACROSS
CENTRAL IL. GUIDANCE SUGGESTS THERE WILL BE SOME MARGINAL
IMPROVEMENT TO IFR/LOW MVFR CIGS LATE SUNDAY MORNING...THOUGH
ANOTHER ROUND OF SHOWERS IS EXPECTED LATE IN THE AFTERNOON AND
EVENING HOURS WHICH WILL LIKELY SERVE TO LOWER CIGS TO
IFR/POSSIBLY LIFR AGAIN. LOW PROBABILITY OF ISOLATED TSRA EXISTS
EARLY SUNDAY EVENING AS WELL...THOUGH GREATEST POTENTIAL SHOULD
REMAIN SOUTH/SOUTHEAST OF TERMINAL SITES. SOLID IMPROVEMENT IN CIG
CONDITIONS/LOW LEVEL DRYING IS NOT EXPECTED UNTIL LATE SUNDAY
NIGHT/EARLY MONDAY MORNING.
WITH SURFACE LOW PRESSURE TRACKING SOUTH OF THE TERMINALS...
NORTHEAST WINDS OF GENERALLY 10-15 KTS ARE EXPECTED THROUGH THE
TAF PERIOD.
RATZER
&&
.MARINE...
255 PM CDT
A LARGE AREA OF HIGH PRESSURE CENTERED OVER CENTRAL CANADA WILL
SLOWLY MOVE TO THE EAST OVER THE NEXT COUPLE DAYS WHILE LOW
PRESSURE OVER THE UPPER MISSOURI VALLEY TRACKS TO THE EAST ACROSS
CENTRAL IL/IN LATE TONIGHT AND TOMORROW. THIS WILL KEEP PERSISTENT
ELY-NELY FLOW OVER THE LAKE. WINDS AND WAVES HAZARDOUS TO SMALL
CRAFT SHOULD CONTINUE OVER THE IL NEARSHORE WATERS THROUGH SUNDAY
NIGHT AS A MODERATE ELY-NELY PRESSURE GRADIENT REMAINS IN PLACE.
HIGH PRESSURE WILL THEN SETTLE ACROSS THE NORTHERN AND CENTRAL
GREAT LAKES REGION ON MONDAY...SETTING UP A PERIOD OF RELATIVELY
QUIET CONDITIONS OVER LAKE MICHIGAN. THE HIGH PRESSURE RIDGE WILL
WEAKEN ON TUESDAY WHILE PUSHING SOUTH INTO THE OHIO VALLEY AND
DEEPENING LOW PRESSURE MOVES SOUTHEAST ACROSS ONTARIO INTO
THE UPPER GREAT LAKES TUESDAY NIGHT WITH A TRAILING COLD FRONT
PUSHING SOUTH ACROSS THE WESTERN LAKES. ANOTHER AREA OF HIGH
PRESSURE BUILDING OVER THE CANADIAN PRAIRIES BY MIDWEEK AS THE LOW
MOVES OFF TO THE EAST SHOULD BRING STRENGTHENING NWLY-NLY FLOW TO
THE LAKE FOR THE MIDDLE AND LATTER PORTIONS OF NEXT WEEK. AT THIS
POINT...EXPECT WINDS TO REMAIN BELOW GALE FORCE...BUT IF THE COLD
ADVECTION AND PRESSURE RISES BEHIND THE EXITING COLD FRONT ARE
STRONG ENOUGH...THE POTENTIAL FOR GALES CANNOT BE RULED OUT BY THE
END OF THE WEEK.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 AM
MONDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1151 PM CDT SAT APR 30 2016
.UPDATE...
Issued at 900 PM CDT Sat Apr 30 2016
Surface low this evening is located just northwest of St. Louis
and expected to move slowly east or ESE overnight...arriving near
Lawrenceville by dawn. An instability axis around 1000 J/KG CAPE
extending from near th low center southward resulted in several
severe thunderstorms from near the Quincy area through the St.
Louis area with over 1 inch hail. Nevertheless, these storms have
remained just outside the central IL forecast area and will
continue to skirt the edges of this forecast area from Near the
Jacksonville area to Shelbyville to Effingham and southward. A
line of thunderstorms east of the St. Louis metro area currently
looks to arrive in Effingham and Clay Counties around 10 p.m.
however nocturnal stabilization may trend these storms sub-severe
by that point. Updates this evening have been for short term radar
trends on thunderstorm coverage. Otherwise, forecast looks in good
shape with lows ranging from the upper 40s in Galesburg and Peoria
to the Upper 50s south of I-70. Showers and thunderstorms will
decrease late in the night with the low shifting
eastward...although showers may arrive by early morning northwest
of the Illinois River.
&&
.SHORT TERM...(Tonight)
ISSUED AT 255 PM CDT Sat Apr 30 2016
19z/2pm surface analysis shows 1004mb low over northern Missouri,
with warm front extending E/SE into southern Illinois. After being
nearly stationary for much of the day, the front is slowly lifting
northward and should eventually stall between the I-72 and I-70
corridors this evening. Most of the steady rain from earlier has
pushed into northern Illinois, leaving behind only isolated showers
across the KILX CWA this afternoon. Will be watching locations near
and south of the warm front where latest LAPS data is showing
SBCAPES of 1000-1500J/kg across Missouri into the Ozarks. Visible
satellite imagery is beginning to show the first signs of convective
development from just west of St. Louis southward into Arkansas.
HRRR suggests scattered thunderstorms will develop within this
corridor over the next couple of hours, then will spread E/NE into
portions of central Illinois tonight. Based on expected position of
front and latest HRRR forecast, think the best storm chances will
remain across the southern half of the CWA through the evening
hours, with any convection pushing further east into Indiana by
midnight. With surface low pressure tracking into the area and
winds becoming light/variable, think fog will become an issue later
tonight within the very moist low-level airmass. While MET/MAV
guidance only show minor reductions in visby, the HRRR is much more
bullish with the fog, particularly near the expected position of the
front. Have therefore included areas of fog in the forecast for all
locations north of I-70, with patchy fog further south into the warm
sector.
.LONG TERM...(Sunday through Saturday)
ISSUED AT 255 PM CDT Sat Apr 30 2016
Morning upper air and satellite imagery showed spinning upper closed
low over northeast CO-southwest NE. Models in good agreement on
drifting it to the east overnight, which should provide upper
support for instability showers over region on Sunday. For
overnight, best instability in area of MO where CAPE values have
increased due to cloud break up this afternoon. Expect storm
development still possible in along and south of warm frontal zone,
then pcpn moving north into central IL region. Pcpn should remain
elevated, as cold dome north of front has been reinforced by
rainfall today, so only marginal risk of severe, with mainly hail
threat in a few stronger storms.
Upper system drifts through on Sunday, with scattered showers
triggered. Pcpn break Sunday night, then a second upper wave moves
through that will trigger slight chance of showers over parts of
area.
Upper flow becomes northwesterly into midweek, with a minor wave
moving through Tuesday night into Wednesday. Instability showers
again possible with cool air aloft with this wave. Temperatures
through next week with be generally cool and below normal.
Surface low expected to track northeast across the region this
evening, reaching northeast Indiana by midnight, although the GFS is
quite a bit slower with this scenario. General thought is that the
steadier showers will be quickly diminishing this evening, with a
good portion of the overnight hours dry. However, the remnants of
the upper low currently along the Colorado/Kansas border will move
across southern Iowa Sunday morning and across Illinois in the
afternoon, bringing another period of scattered showers to the area
by midday. Have included isolated thunder mention in the afternoon
most areas, as the trough moves overhead. Any lingering showers
should be out of the area around sunset.
Highly amplified pattern expected next week, as upper level ridging
over the western U.S. builds well into British Columbia and Alberta.
Longer range models showing some differences with the extent of the
corresponding upper trough over the eastern half of the CONUS, with
the ECMWF on the deeper side. This would trend toward significantly
cooler conditions over the Midwest during the second half of the
work week. By the end of the week, the upper pattern on both the GFS
and ECMWF models trends toward an omega block type configuration
which would linger the cooler air even longer. Have trended downward
on the temperatures for late in the week, although not as low as the
blended raw model guidance at this point.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1150 PM CDT Sat Apr 30 2016
A region of predominantly LIFR ceilings and areas of fog is
currently settling slowly southward across central IL according to
surface observations and satellite imagery. Low pressure
translating eastward across southern IL will continue to draw the
region southward through the night. Some improvement expected by
late morning as daytime heating occurs. An upper low off to the
west will cross over the area late in the afternoon developing
scattered showers and perhaps an isolated thunderstorm as well.
Included VCTS at KPIA-KBMI closer to the upper level cold pool of
this feature, but otherwise probabilites appear to low to include
at this point.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Onton
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Onton
AREA FORECAST DISCUSSION
NWS JACKSON KY
240 AM EDT SUN MAY 1 2016
.UPDATE...
ISSUED AT 240 AM EDT SUN MAY 1 2016
WITH PRECIP ONGOING...RAISED POPS FOR THE OVERNIGHT. ALSO BLENDED
OBS INTO THE ONGOING FORECAST.
UPDATE ISSUED AT 1048 PM EDT SAT APR 30 2016
MADE ONE LAST UPDATE TO MAKE SURE THE ONGOING PRECIP WAS WELL
DEPICTED IN THE FORECAST...AS WELL AS TO TWEAK WHAT IS EXPECTED
DURING THE REST OF THE NIGHT. AS WAS PREVIOUSLY DISCUSSED...EVEN
HI RES MODELS ARE STILL HAVING A HARD TIME HANDLING THE ONGOING
PRECIP AS THE WARM FRONT MOVES NORTHWARD. THE HRRR CONTINUES TO
HAVE THE BEST HANDLE OVERALL...SO WENT WITH A MIX OF
OFFICIAL...HRRR...AND HAND TWEEKS TO COME UP WITH EXPECTED
SCENARIO. WE ARE CONTINUING TO SEE A DIMINISHMENT OF RAIN RATES
ACROSS EASTERN KY...SO PROBABLY NOT SEEING MUCH IN CLOUD LIGHTNING
AT THE MOMENT. HOWEVER...RAIN RATES COULD INCREASE...AND A FEW
HEAVIER SHOWERS TO OUR SW MAY MAKE IT INTO THE CWA...SO KEPT
MENTION OF ISOLATED THUNDER THROUGHOUT THE NIGHT AS A PRECAUTION.
IN ADDITION TO THE PRECIP UPDATE...ALSO MADE SURE THE TEMPS...DEW
POINTS...AND WINDS WERE WELL IN LINE WITH THE CURRENT CONDITIONS.
ALL CHANGES HAVE BEEN PUBLISHED AND SENT TO NDFD/WEB...THOUGH
CHANGES SHOULD NOT BE SIGNIFICANT ENOUGH TO WARRANT ANY FURTHER
ZFP UPDATES.
UPDATE ISSUED AT 855 PM EDT SAT APR 30 2016
SHOWERS ARE BEGINNING TO FILL INTO EASTERN KY FROM THE WEST AND
SOUTH AS A WARM FRONT CONTINUES TO LIFT THROUGH THE STATE. MOST OF
THE THUNDERSTORMS THAT HAD DEVELOPED TO OUR SOUTH THIS EVENING
HAVE SINCE WEAKENED AND ARE NOW JUST HEAVY SHOWERS.
HOWEVER...WOULDN/T RULE OUT SOME STRAY THUNDERSTORMS FROM SOME OF
THE HEAVIEST SHOWERS AS THEY MAKE THEIR WAY ACROSS EASTERN KY
OVERNIGHT. GIVEN THE LACK OF MODEL AGREEMENT...TRIED TO BASE NEAR
TERM UPDATED GRIDS ON CURRENT RADAR TRENDS...THEN BLENDED BACK
INTO THE HIRES MODELS THAT SEEM TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION. THIS WILL RESULT IN THE FIRST ROUND OF RAIN
SHOWERS AND ISOLATED THUNDER THROUGH THE NEXT FEW HOURS...THEN
ANOTHER HEAVIER BAND DEVELOPING ACROSS EAST CENTRAL KY AND MOVING
THROUGH THE CWA LATE TONIGHT/EARLY SUN MORNING. GIVEN THE
UNCERTAINTY...WILL CONTINUE TO MONITOR THROUGHOUT THE EVENING IN
CASE ANY FURTHER UPDATES NEED TO BE MADE.
THE OTHER MAIN CHANGE CAME WITH TEMPERATURES. GIVEN THE CLOUDS AND
RAIN...WE HAVE ACTUALLY REMAINED COOLER THAN ORIGINALLY
FORECASTED. THIS RESULTED IN NOT ONLY SOME TWEAKS TO THE CURRENT
TEMPS...BUT ALSO FOR THE DIURNAL CURVE THIS EVENING AND THROUGH
THE OVERNIGHT. AS IT STANDS...WE WILL LIKELY NOT SEE MUCH OF A
DROP DURING THE OVERNIGHT...ESPECIALLY WITH THE EXPECTED
WIDESPREAD RAIN AND CLOUD COVER...SO ONLY EXPECTING A FEW DEGREES
OF VARIATION FROM THE CURRENT ONGOING TEMPS.
ALL CHANGES HAVE BEEN SAVED AND SENT TO NDFD/WEB. A NEW FORECAST
PACKAGE WAS ALSO SENT OUT TO REFLECT THESE CHANGES.
UPDATE ISSUED AT 735 PM EDT SAT APR 30 2016
UNFORTUNATELY MODELS...EVEN HI RES...DO NOT HAVE A GOOD HANDLE ON
THE ONGOING SHOWERS AND THUNDERSTORMS ACROSS KY...TN...AND POINTS
SURROUNDING. HOWEVER...GIVEN THE CURRENT RADAR TRENDS...AN UPDATE
TO POPS AND WEATHER WAS DEEMED NECESSARY. AND MAY BE AGAIN IN THE
NEAR FUTURE DUE TO SHOWERS AND THUNDERSTORMS THAT HAVE NOW
DEVELOPED TO OUR SOUTH. TRIED TO USE THE BEST HI RES MODEL BLEND
AS A STARTING POINT AND THEN HAND TWEAKED GRIDS TO GET DESIRED
POP TREND. ALSO...CHANGED PROBABILITY WORDING TO COVERAGE WORDING
THROUGH THE OVERNIGHT SINCE PRECIP IS ONGOING. ALL CHANGES HAVE
BEEN SAVED AND SENT TO NDFD/WEB...AND NEW FORECAST ZONES WERE SENT
OUT AS WELL TO ADDRESS THE CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 400 PM EDT SAT APR 30 2016
CURRENT CONDITIONS ACROSS THE AREA FEATURE AN AREA OF SHOWERS AND
A FEW EMBEDDED THUNDERSTORMS MOVING NORTHEAST AHEAD OF A WARM
FRONT LIFTING NORTH THROUGH THE AREA. AS THIS AREA LIFTS THROUGH
TO THE NORTHEAST...A BREAK IN THE RAIN WILL OCCUR. AS SOUTHERLY
FLOW INCREASES AND THE FRONT SHIFTS NORTH INTO THE AREA...SOME
ADDITIONAL CONVECTION IS EXPECTED TO DEVELOP WITH SOME STORMS
PRODUCING HEAVY DOWNPOURS. WHILE SOME PONDING ON ROADS ARE
POSSIBLE...THE AREA IS FULLY GREENED UP AND WITH PWATS ONLY
REACHING JUST BELOW THE 2ND STANDARD DEVIATION...WILL NOT EXPECT
ANY FLOODING ISSUES TONIGHT. CONCERNING THE STRONG STORM
THREAT...AS THE FRONT APPROACHES TONIGHT...JUST ENOUGH FORCING AND
SHEAR WILL BE AVAILABLE FOR POSSIBLY A STRONG STORM OR TWO. IN
FACT TEMPS WILL REMAIN NEARLY STEADY THROUGH THIS EVENING AND
TONIGHT AS TEMPS ONLY DROP BACK INTO THE LOW 60S.
FOR SUNDAY...AS THE NEXT PIECE OF ENERGY MOVES THROUGH THE
MIDWEST AND INTO THE OH VALLEY...ANOTHER INSTANCE OF STRONG STORMS
WILL BE POSSIBLE. WITH EAST KENTUCKY BEING IN THE WARM
SECTOR...THE CAP OVER THE AREA WILL BE A BIT STOUT. HEADING INTO
THE DAY ON SUNDAY...IF INSTABILITY IS ENOUGH TO BREAK THE CAP AND
CAN OVERCOME THE LOW LEVEL DRY AREA...SOME STRONG STORMS ARE
POSSIBLE ON SUNDAY WITH HAIL AND DAMAGING WINDS THE THREAT. HAVE
MENTIONED THIS IN THE HWO.
HEADING INTO SUNDAY NIGHT...THE FRONT LOOKS TO STALL OUT OVER THE
EAST WITH SOME LINGERING SHOWERS INTO SUNDAY NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 311 PM EDT SAT APR 30 2016
THE EXTENDED PERIOD WILL FEATURE PERIODS OF ISOLATED TO SCATTERED
RAIN SHOWERS AND COOLER WEATHER THAT WHAT WE HAVE BEEN
EXPERIENCING THE PAST COUPLE OF WEEKS. THE MODELS ALL HAVE A LARGE
TROUGH OF LOW PRESSURE ALOFT DIVING OUT OF CANADA AND BASICALLY
SPINNING IN PLACE OVER THE SOUTHEASTERN GREAT LAKES REGION AND
SOUTHWESTERN NEW ENGLAND THROUGH OUT THE UPCOMING WORK WEEK. THE
WEATHER SYSTEM THAT WILL BRING SHOWERS AND STORMS TO EASTERN
KENTUCKY TODAY AND TOMORROW...WILL BE DEPARTING THE AREA MONDAY
AND MONDAY NIGHT. ONCE THAT SYSTEM MOVES OFF TO OUR EAST...A MUCH
LARGER AND MORE WELL DEVELOPED TROUGH IS FORECAST TO INFLUENCE THE
WEATHER OF EASTERN KENTUCKY THROUGH THE END OF THE WEEK. MULTIPLE
SHORT WAVES WILL MIGRATE AROUND THE WESTERN PERIPHERY OF THE UPPER
TROUGH...WHICH WILL BRING US PERIODS OF RAIN SHOWERS DURING THE
WEEK. THE RAIN WILL BE LIGHT AND SHOULD NOT PRESENT ANY MAJOR
ISSUES. WE WILL JUST BE IN STORE FOR A DAMP AND CLOUDY WEEK WITH
PERIODS OF SCATTERED RAIN SHOWERS.
TEMPERATURES DURING THE PERIOD WILL GENERALLY RUN AT OR BELOW
NORMAL AS THE TROUGH PULLS COOL MOIST AIR INTO THE REGION. DAY
TIME HIGHS WILL VARY FROM THE LOW TO MID 60S DURING THE RAINIEST
PERIODS...TO AROUND 70 ON THE LESS RAINY LESS CLOUDY DAYS.
OVERNIGHT LOWS WILL MOSTLY BE IN THE 40S ACROSS THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 240 AM EDT SUN MAY 1 2016
A DIFFUSE WARM FRONT LIFTING NORTH OVER THE REGION IS RESPONSIBLE
FOR ONGOING SHOWERS AND THUNDERSTORMS. THEY WERE BRINGING
LOCALIZED MVFR AND IFR CONDITIONS. HOWEVER...MOST LOCATIONS WERE
STILL VFR. THIS SCENARIO SHOULD CONTINUE UNTIL PRECIP TAPERS OFF
AND VFR RETURNS EVERYWHERE. THE BACK EDGE OF THE GENERAL AREA OF
SHOWERS AND STORMS WILL MOVE EASTWARD ACROSS THE REGION BETWEEN
ABOUT 09Z AND 13Z. THIS SHOULD LEAVE A FAIRLY QUIET START TO THE
DAY ON SUNDAY. HOWEVER...AS HEATING AND DESTABILIZATION
OCCUR...REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS IS POSSIBLE IN
THE AFTERNOON AND EVENING. THE BIG QUESTION/UNCERTAINTY IS
INITIATION OF CONVECTION AND THE EXTENT OF COVERAGE. STORMS THAT
DO DEVELOP HAVE A POTENTIAL FOR HAIL AND STRONG WINDS ON SUNDAY
AFTERNOON AND EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1205 AM CDT SUN MAY 1 2016
.AVIATION...
FOR THE 01/06Z TAFS...ISOLATED CONVECTION HAS DEVELOPED ALONG AND
AHEAD OF A WEAK COLD FRONT THAT IS LOCATED FROM KDEQ...TO NEAR
KMNE...TO BETWEEN KLFK AND KJAS. CONVECTION HAS BEEN MORE ROBUST
AND HAS PERSISTED ACROSS SRN AR BUT HAS STRUGGLED FARTHER SOUTH.
ISOLATED SHWRS/TSTMS WILL REMAIN POSSIBLE FOR MUCH OF THE PERIOD
AS THE WEAK FRONT ADVANCES SEWD AND BECOMES DIFFUSE. HOWEVER...
CONFIDENCE IS LOW ON IMPACTS AT THE TAF SITES SO NO MENTION OF
PRECIP WAS INCLUDED WITH THIS ISSUANCE. LOW CIGS AND
FOG...INCLUDING SOME PATCHY DENSE FOG...SHOULD DEVELOP ACROSS MUCH
OF THE AREA OVERNIGHT. CIGS/VSBYS WILL IMPROVE AFTER SUNRISE AND
VFR CONDITIONS SHOULD PREVAIL BY 01/18Z. THE NEXT SIGNIFICANT
ROUND OF PRECIP MAY BEGIN TO AFFECT PORTIONS OF THE AREA DURING
THE LAST FEW HRS OF THE TAF PERIOD. /09/
&&
.PREV DISCUSSION... /ISSUED 949 PM CDT SAT APR 30 2016/
DISCUSSION...
THE WEAK SFC TROUGH CONTINUES TO MAKE SLOW PROGRESS ESE THIS
EVENING...AND NOW EXTENDS FROM NEAR A MWT...TO TXK...TO JUST E OF
ASL...TO LFK AND CXO LINE AS OF 0230Z. DID SEE A FEW TOWERS
DEVELOP ALONG THIS TROUGH JUST W OF SHV SHORTLY BEFORE
SUNSET...WITH EVEN A COUPLE OF ISOLATED SHRA HAVING RECENTLY
DEVELOPED ALONG THIS BNDRY IN SE CASS COUNTY TX...AS WELL AS OVER
TXK. THE SHORT TERM PROGS CONTINUE TO SUGGEST THIS BNDRY EASING A
BIT FARTHER SE INTO THE LOWER TOLEDO BEND COUNTRY AND NCNTRL LA
BEFORE PULLING UP STATIONARY LATE...WITH ISOLATED TO POSSIBLY
WIDELY SCT CONVECTION REDEVELOPING ALONG/JUST AHEAD OF THE BNDRY
WHERE THE AIR MASS REMAINS MODERATELY UNSTABLE. DID NOT MAKE ANY
CHANGES TO POPS TONIGHT...AND MADE ONLY MINOR CHANGES TO THE
CURRENT MIN TEMP FORECAST TO REFLECT THE CURRENT TRENDS. CAN/T
RULE OUT PATCHY FG DEVELOPING LATE ALONG/JUST AHEAD OF THE TROUGH
OVER DEEP E TX/NCNTRL LA...BUT WITH THE CURRENT CU FIELD AND
EVENTUALLY THE LOW STRATUS THAT SHOULD FORM LATE...AS WELL AS ANY
CONVECTION THAT MAY DEVELOP...WILL NOT ADD IT TO THE FORECAST
ATTM.
THE CURRENT FORECAST REMAINS ON TRACK AND NO ADDITIONAL CHANGES
ARE NEEDED THIS EVENING.
15
PREV DISCUSSION... /ISSUED 730 PM CDT SAT APR 30 2016/
DISCUSSION...
THE EVENING SFC ANALYSIS INDICATES A WEAK SFC TROUGH/PSEUDO-FRONT
EXTENDING IN A N-S LINE FROM EXTREME WRN AR S TO NEAR DEQ...TO
JUST E OF GGG...TO NEAR A LFK AND CXO LINE. SATELLITE TRENDS THIS
AFTERNOON AND A WALK OUTSIDE IN THE PARKING LOT REVEALS A FLAT CU
FIELD IN PLACE...DESPITE THE STRONG SFC-BASED INSTABILITY IN PLACE
AFTER TEMPS RECOVERED WELL INTO THE LOWER/MID 80S WITHIN THE HUMID
AIR MASS IN PLACE. THE WATER VAPOR IMAGERY ALSO SHOWS A BROAD SLUG OF
DRY AIR WRAPPING N AND E ACROSS THE MS VALLEY AROUND THE CLOSED
LOW OVER SW NE/NW KS...WITH VERY LITTLE IN THE WAY OF DEEP LYR
FORCING THIS FAR S OF THE CLOSED LOW. HOWEVER...GIVEN THE UNSTABLE
AIR MASS IN PLACE AND AMOUNT OF LOW LEVEL MOISTURE IN
PLACE...STILL CAN/T RULE OUT ISOLATED CONVECTION DEVELOPING LATER
THIS EVENING/OVERNIGHT NEAR/JUST E OF THE SFC TROUGH AS IT DRIFTS
ESE INTO THE LOWER TOLEDO BEND COUNTRY AND NCNTRL LA LATE BEFORE
BECOMING STATIONARY. THE SHORT TERM PROGS AND THE LATEST RUNS OF
THE HRRR ARE NOT VERY BULLISH AT ALL WITH CONVECTION DEVELOPING
NEAR/E OF THE TROUGH...THUS HAVE SCALED BACK POPS TONIGHT FOR
THESE AREAS. HAVE ALSO CANCELLED THE FLASH FLOOD WATCH THAT WAS IN
EFFECT FOR PORTIONS OF DEEP E TX/NCNTRL LA...AS THE FLOOD THREAT
HAS ENDED.
THE SFC TROUGH WILL FOCUS ADDITIONAL ISOLATED/SCT CONVECTION
DEVELOPMENT SUNDAY AS IT BEGINS TO SLOWLY LIFT BACK N ACROSS THE
REGION...ALTHOUGH RAINFALL AMOUNTS SHOULD STILL REMAIN LIGHT
THROUGH THE AFTERNOON OVER DEEP E TX/NCNTRL LA SUCH THAT FLOODING
SHOULD NOT BE A PROBLEM. THIS IS IN ADDITION TO THE FACT THAT
THESE AREAS DID NOT SEE AS MUCH RAIN AS AREAS FARTHER TO THE N
ACROSS NW LA/SW AR/MUCH OF E TX/SE OK. DID TONE DOWN POPS JUST A
TAD FOR THE FAR SRN ZONES...WITH THE GREATER COVERAGE IN
CONVECTION EXPECTED TO REMAIN JUST S OF THE REGION OVER SE
TX/CNTRL/SRN LA.
DID NOT ADJUST THE MIN TEMP FORECAST TONIGHT...BUT WILL RE-
EVALUATE DURING THE MID-EVENING DISCUSSION.
ZONE UPDATE/WATCH CANCELLATION ALREADY OUT...GRIDS WILL BE
AVAILABLE SHORTLY.
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 66 82 64 75 / 20 20 70 70
MLU 69 84 66 74 / 30 30 70 80
DEQ 56 79 56 71 / 20 10 70 50
TXK 62 80 59 71 / 20 10 70 60
ELD 63 81 61 72 / 20 20 70 70
TYR 62 81 60 72 / 10 20 60 60
GGG 63 81 61 73 / 10 20 70 60
LFK 69 82 66 77 / 20 40 70 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1159 PM CDT SAT APR 30 2016
.DISCUSSION...
FOR 06Z TAF ISSUANCE.
&&
.AVIATION...
LOCAL 88DS SHOW THE POTENTIAL NEXT ROUND OF SHOWERS ALREADY
DEVELOPING OVER LOWER ACADIANA...AFFECTING THE SERN TERMINALS BY
06Z. LATEST HRRR RUNS SHOW WIDESPREAD SHOWERS DEVELOPING FURTHER
WEST THROUGH THE OVERNIGHT HOURS...IMPACTING MAINLY KLCH/MAYBE
KBPT FIRST BEFORE REACHING KAEX LATER. MEANWHILE MEDIUM-RANGE
MODELS STILL SHOW THE BULK OF THE PRECIP IN BETTER CONFINEMENT
WITH THE LINGERING FRONT...AGAIN IMPACTING THE SERN SITES MORE
THAN THE OTHERS. CEILINGS SHOULD REMAIN ON THE LOW SIDE GIVEN SO
MUCH BOUNDARY LAYER MOISTURE AND NOCTURNAL INVERSIONS.
25
&&
.PREV DISCUSSION... /ISSUED 944 PM CDT SAT APR 30 2016/
UPDATE...MINOR TWEAKING OF POPS OVER THE AREA. LATEST MODEL
OUTPUT CONTINUES TO SUGGEST ACADIANA POTENTIAL HIGHEST AREA-WIDE
AND HAVE MAINTAINED LIKELY POPS THERE. DID TRIM DOWN POPS
SLIGHTLY ELSEWHERE.
PREV DISCUSSION... /ISSUED 900 PM CDT SAT APR 30 2016/
DISCUSSION...
FOR 00Z TAF ISSUANCE.
AVIATION...
LOWER CEILINGS ARE BEGINNING TO DEVELOP ACROSS THE AREA WITH SFC
OBS REPORTING MVFR CONDITIONS NOW STARTING TO PREVAIL. CIGS SHOULD
CONTINUE LOWERING THROUGH THE NIGHT WITH LIFR VALUES EXPECTED BY
DAYBREAK...ALONG WITH POSSIBLY SOME SLIGHT RESTRICTIONS TO
VISIBILITY. ALL MODELS ARE INDICATING WIDESPREAD SHOWER ACTIVITY
DEVELOPING AHEAD OF AN APPROACHING FRONTAL BOUNDARY...LIKELY MOST
IMPACTING KLFT/KARA STARTING AROUND SUNRISE SUNDAY AND LINGERING
THROUGH MUCH OF THE DAY.
25
PREV DISCUSSION... /ISSUED 430 PM CDT SAT APR 30 2016/
DISCUSSION...A LARGE UPPER LOW CONTINUES TO MOVE ACROSS THE
PLAINS THIS AFTERNOON WITH A SHORT WAVE PASSING TO THE SOUTH ALONG
THE OF THE LARGER LOW. MOST OF THE RAIN ASSOCIATED WITH THE SHORT
WAVE HAS EXITED THE AREA, EXCEPT FOR FAR SOUTH LA. SOME MODELS
INDICATE THAT ADDITIONAL SHOWERS WILL CONTINUE TO DEVELOP ALONG
THE TAIL END OF THIS MCS AND CONTINUE INTO LOWER ACADIANA THIS EVENING.
ALSO A WEAK FRONTAL BOUNDARY IS LOCATED IN EAST TX AND THIS MAY
DRIFT INTO OR NEAR THE EAST TX LAKES AREA EARLY SUNDAY WITH
ADDITIONAL SHOWER ACTIVITY DEVELOPING TOWARD SUNRISE.
ANOTHER SHORT WAVE WILL MOVE ACROSS THE REGION MONDAY WITH ANOTHER
ROUND OF HEAVY RAINFALL POSSIBLE.
WHILE WIDESPREAD HEAVY RAINFALL IS NOT EXPECTED SUNDAY,
WITH THE ALREADY SATURATED SOIL AND FULL RIVERS, BAYOUS, AND
DITCHES THE FLOOD WATCH WAS EXTENDED INTO MONDAY EVENING WHEN THE
NEXT MCS MAY AFFECT THE AREA.
THE FRONT IS NOT EXPECTED TO PUSH THROUGH THE REGION MONDAY ENDING
THE RAINFALL AND USHERING IN COOLER AND DRIER WEATHER FOR MID TO
LATE WEEK.
MARINE...TIDE LEVELS ARE FALLING ALONG THE COAST, HOWEVER TIDES
WILL CONTINUE TO RUN AROUND ONE FOOT ABOVE NORMAL THROUGH SUNDAY.
THIS MAY PUSH TIDES BACK TO AROUND 3 FEET MLLW AT HIGH TIDE MID
DAY TO EARLY AFTERNOON SUNDAY. A SLOW DECREASE IN TIDES IS
EXPECTED THROUGH EARLY WEEK WITH A BETTER FALL AFTER THE FRONT
TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 69 82 68 77 / 30 60 50 80
LCH 71 81 71 79 / 40 60 50 80
LFT 71 82 74 80 / 60 70 40 80
BPT 70 83 71 80 / 30 60 60 80
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR LAZ027>033-041>045-
052>055-073-074.
COASTAL FLOOD ADVISORY UNTIL 5 PM CDT SUNDAY FOR LAZ041-052>054-
073-074.
TX...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR TXZ180-201-215-216-
259>262.
COASTAL FLOOD ADVISORY UNTIL 5 PM CDT SUNDAY FOR TXZ215-216.
GM...NONE.
&&
$$
Area Forecast Discussion
National Weather Service Springfield MO
319 AM CDT SUN MAY 1 2016
.SHORT TERM...(Today and tonight)
Issued at 251 AM CDT Sun May 1 2016
Sfc low pressure over far se Neb extends east to a sfc wave near
KSTL and western IL while a trailing sfc cold front extends south
over our far eastern cwfa in south central MO. Drier sfc air has
moved into all but our far se counties. Earlier convection has
weakened while shifting south and east of the area. Where higher
dew points hang on, some fog will occur where the sky clears
(already seeing that at KUNO and on webcams over south central
MO). Fog is expected to become more common as the sky continues to
clear over south central MO over the next few hours. Some
fog may also occur near lakes.
An upper level shortwave along the eastern Neb/KS border will move
east helping to ease the sfc low and trailing front away from our
area. Warmer temperatures will hold on over our eastern counties
today before drier/cooler winds veer more to the nw-nnw tonight.
.LONG TERM...(Monday through Saturday)
Issued at 251 AM CDT Sun May 1 2016
A blocking pattern will remain established with a high amplitude
ridge over western NOAM. We will be on the downstream side of the
ridge with nw flow shortwaves keeping us cool with some
clouds/sprinkles/very light trace amount rain at times Mon and
Tue. Will carry some low pops for measurable rain in the fcst for
this time period somewhat favoring the afternoon/early evening
periods.
We will see the tail end of one more shortwave moving southeast
through the Midwest Wed. Unseasonably cool temperatures early in
the week will moderate somewhat through Wed. Then after a brief
cool down again Thu, temperatures should warm nicely for the end
of the week as the western upper level ridge axis moves into the
Plains. Some areas could see or at least push 80 deg F over the
western cwfa Sat.
In terms of impactful weather this week, it looks quiet. Very good
agreement with operational global models (ECMWF and GFS) through
Saturday starts to break down a bit in terms of how quickly another
system will move into the Plains early next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1145 PM CDT Sat Apr 30 2016
Patchy fog is expected late tonight and early Sunday morning as
winds become nearly calm. The fog will be shallow in nature with
visibilities being highly variable.
Any fog will then dissipate by mid-morning on Sunday with VFR
expected into the evening. Winds will be light out of the west on
Sunday.
&&
.SGF Watches/Warnings/Advisories...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Schaumann
Area Forecast Discussion
National Weather Service Springfield MO
319 AM CDT SUN MAY 1 2016
.SHORT TERM...(Today and tonight)
Issued at 251 AM CDT Sun May 1 2016
Sfc low pressure over far se Neb extends east to a sfc wave near
KSTL and western IL while a trailing sfc cold front extends south
over our far eastern cwfa in south central MO. Drier sfc air has
moved into all but our far se counties. Earlier convection has
weakened while shifting south and east of the area. Where higher
dew points hang on, some fog will occur where the sky clears
(already seeing that at KUNO and on webcams over south central
MO). Fog is expected to become more common as the sky continues to
clear over south central MO over the next few hours. Some
fog may also occur near lakes.
An upper level shortwave along the eastern Neb/KS border will move
east helping to ease the sfc low and trailing front away from our
area. Warmer temperatures will hold on over our eastern counties
today before drier/cooler winds veer more to the nw-nnw tonight.
.LONG TERM...(Monday through Saturday)
Issued at 251 AM CDT Sun May 1 2016
A blocking pattern will remain established with a high amplitude
ridge over western NOAM. We will be on the downstream side of the
ridge with nw flow shortwaves keeping us cool with some
clouds/sprinkles/very light trace amount rain at times Mon and
Tue. Will carry some low pops for measurable rain in the fcst for
this time period somewhat favoring the afternoon/early evening
periods.
We will see the tail end of one more shortwave moving southeast
through the Midwest Wed. Unseasonably cool temperatures early in
the week will moderate somewhat through Wed. Then after a brief
cool down again Thu, temperatures should warm nicely for the end
of the week as the western upper level ridge axis moves into the
Plains. Some areas could see or at least push 80 deg F over the
western cwfa Sat.
In terms of impactful weather this week, it looks quiet. Very good
agreement with operational global models (ECMWF and GFS) through
Saturday starts to break down a bit in terms of how quickly another
system will move into the Plains early next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1145 PM CDT Sat Apr 30 2016
Patchy fog is expected late tonight and early Sunday morning as
winds become nearly calm. The fog will be shallow in nature with
visibilities being highly variable.
Any fog will then dissipate by mid-morning on Sunday with VFR
expected into the evening. Winds will be light out of the west on
Sunday.
&&
.SGF Watches/Warnings/Advisories...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Schaumann
[top]
Area Forecast Discussion
National Weather Service Saint Louis MO
303 AM CDT SUN MAY 1 2016
.SHORT TERM... (Through Late This Afternoon)
Issued at 302 AM CDT Sun May 1 2016
Patchy dense fog over northeast Missouri, west central Illinois to
dissipate and thin out towards daybreak. So main issue for today
will be the closed upper level low currently over south central
Nebraska that will finally open up and slide east across northern
Missouri. Will see scattered showers and a few thunderstorms
possible, especially along and north of I70 in Missouri and along
and east of Mississippi River in Illinois. Some of the storms will
be strong over southwestern Illinois where CAPES will be in excess
of 1500 J/kg this morning through the afternoon hours, as well as
decent low level lapse rates and some shear. Could see some small
hail and wind gusts to 45 mph with the stronger storms.
As for high temps today, with mostly cloudy skies will have a wide
variation from the upper 50s far north to the mid 70s far southeast.
Byrd
.LONG TERM... (Tonight through Saturday)
Issued at 302 AM CDT Sun May 1 2016
Expect thunderstorms to be ongoing at the beginning of the forecast
period, but to be E of the CWA at 00z this evening.
Mdls are in fairly good agreement with upper trof hanging up over IA
on Mon with a s/w moving thru the area. While the bulk of the precip
shud remain S of the area, this s/w and cold temps aloft shud be
enuf to support SHRA across much of the area. Given the diurnal
nature of these SHRA, expect Mon night to be dry with isod to widely
sct SHRA again on Tues as the upper trof sinks thru the region. Some
uncertainty remains how much of the area will be see any precip, but
given the expected location of the upper trof Tues morning, have
kept PoPs confined to the srn two thirds of the CWA.
The next chance for precip is Wed as another cdfnt drops thru the
area. Mdls differ regarding how much moisture will be available as
the fnt moves thru. Will keep low PoPs going for ern portions of the
CWA where a s/w rotating around the back of the upper low may
provide enuf support for some SHRA. The remainder of the forecast is
dry as a large sfc ridge builds into the area.
Overall, temp forecast will remain aob seasonal avg. thru this week
with a sfc ridge in place as mentioned above. Wed shud be slightly
warmer with more insolation expected and wly to swly winds ahead of
the approaching cdfnt. The next warm up shud be Sat as an upper
ridge builds into the area with sfc winds becoming sly again.
Tilly
&&
.AVIATION... (For the 06z TAFs through 06z Sunday Night)
Issued at 1101 PM CDT Sat Apr 30 2016
A cold front extends from a surface low near PPQ south-southwest
through southwestern AR. Scattered showers and thunderstorms
should move out of the St Louis metro area by 06Z Sunday. With
light surface winds and recent rainfall, patchy fog should develop
late tonight in the St Louis metro area and also possibly in COU
as well. Stratus clouds below 1000 feet along with visibilities
below 1SM in fog will likely continue late tonight and early
Sunday morning in UIN. Fog will gradually dissipate by late Sunday
morning with ceilings rising into the MVFR catagory by afternoon
at UIN. Scattered-broken diurnal cumulus clouds should develop
late Sunday morning and afternoon with widely scattered showers
possible in UIN during the afternoon ahead of an upper level
disturbance. Surface winds should be mainly w-nwly on Sunday with
a surface ridge building into the area from the Plains.
Specifics for KSTL: Showers and thunderstorms will likely move out
of the STL area by 06Z Sunday. Light fog can be expected late
tonight and early Sunday morning as the wind becomes light.
Scattered to broken diurnal cumulus clouds will develop late
Sunday morning and afternoon with a w-nwly surface wind. The cloud
ceiling may lower into the MVFR catagory late Sunday night.
GKS
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 71 52 61 49 / 20 10 20 10
Quincy 59 44 59 44 / 50 10 20 10
Columbia 64 46 60 44 / 10 10 20 10
Jefferson City 66 47 61 44 / 10 10 20 10
Salem 72 49 61 48 / 30 10 30 10
Farmington 73 47 62 45 / 10 10 30 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
[top]
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
246 AM CDT SUN MAY 1 2016
.Discussion...
Issued at 245 AM CDT SUN MAY 1 2016
Upper-level low pressure continues to spin across the Central Plains
this morning...with latest surface obs showing an inverted trough
extending northwest across our area from parent low pressure now
centered just north of STL. Fcst models all in general agreement
that lgt shwrs will develop later this morning as weak frontogenesis
combines with increased forcing for ascent as the upper low inches
closer to the area. Best chances for measurable precip will reside
along and north of Route 36 based on expected frontogenesis
maximum...however a few stray shwrs down to I-70 cannot be ruled out
completely. In any event however...all precip should remain light
considering the absence of any instability. As this upper low tracks
east...expect developing cold air advection today as flow becomes
more northwesterly as the day progresses. This combined with abundant
cloud cover should lead to noticeably cooler temps today with many
places north of I-70 struggling to reach the 60 degree mark. Precip
chances should come to an end by late this afternoon with a return of
dry weather overnight as weak sfc high pressure temporarily noses
into the area. Overnight lows should fall into the lower to middle
40s across much of the forecast area.
Weak wave now seen over the Desert Southwest will lift northeast
through the day on Monday...with continued cold temps aloft
combining with weak synoptic scale forcing to result in instability
shwrs once again. For now...best area of concentrated rainfall will
reside well south across Arklatex region which will be better
positioned for Gulf moisture entrainment. Regardless...model signal
has been consistent in recent days and a slgt chc mention seems
warranted. Pretty much the same story on Tuesday as another weak wave
passes south over the area in northwest flow aloft. Instability shwrs
again look possible across the eastern zones and have added a slgt
chc mention for now.
Beyond this...a period of dry weather can be expected through the
duration of the work week as a strong omega block develops across the
Nation`s Heartland. From this vantage point...hard to believe much in
the way of any significant precip can be expected through the start
of next weekend as riding takes up position directly over the Plains.
With heights building aloft...expect a warming trend with mid/upper
70s likely both Saturday and Sunday. Along with the warmer
temps...latest model runs hint the strong ridge will begin to
breakdown by Saturday as weak shortwave energy begins sliding through
the upper Miss Vly. This could result in developing shwrs/storms
both Saturday afternoon and Sunday.
&&
.Aviation...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 627 PM CDT SAT APR 30 2016
VFR conds will prevail thru tonight will sct-bkn cigs around 4kft.
Tomorrow morning a sfc trof will sink thru the terminals bringing
MVFR cigs btn 1-2kft. The NAM also suggests the potential for fog
reducing vsbys to 1-2SM however, it is the only model that does so.
Consequently, have kept fog formation out of the TAF at this time
but will continue to monitor. MVFR cigs will lift to 2-3kft around
17Z-19Z with the potential for further lifting to low-end VFR by the
end of the TAF pd. Winds will be out of the west blw 10kts thru
tomorrow morning before veering to the NW around 10kts tomorrow
afternoon.
&&
.EAX Watches/Warnings/Advisories...
KS...None.
MO...None.
&&
$$
Discussion...32
Aviation...73
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
246 AM CDT SUN MAY 1 2016
.Discussion...
Issued at 245 AM CDT SUN MAY 1 2016
Upper-level low pressure continues to spin across the Central Plains
this morning...with latest surface obs showing an inverted trough
extending northwest across our area from parent low pressure now
centered just north of STL. Fcst models all in general agreement
that lgt shwrs will develop later this morning as weak frontogenesis
combines with increased forcing for ascent as the upper low inches
closer to the area. Best chances for measurable precip will reside
along and north of Route 36 based on expected frontogenesis
maximum...however a few stray shwrs down to I-70 cannot be ruled out
completely. In any event however...all precip should remain light
considering the absence of any instability. As this upper low tracks
east...expect developing cold air advection today as flow becomes
more northwesterly as the day progresses. This combined with abundant
cloud cover should lead to noticeably cooler temps today with many
places north of I-70 struggling to reach the 60 degree mark. Precip
chances should come to an end by late this afternoon with a return of
dry weather overnight as weak sfc high pressure temporarily noses
into the area. Overnight lows should fall into the lower to middle
40s across much of the forecast area.
Weak wave now seen over the Desert Southwest will lift northeast
through the day on Monday...with continued cold temps aloft
combining with weak synoptic scale forcing to result in instability
shwrs once again. For now...best area of concentrated rainfall will
reside well south across Arklatex region which will be better
positioned for Gulf moisture entrainment. Regardless...model signal
has been consistent in recent days and a slgt chc mention seems
warranted. Pretty much the same story on Tuesday as another weak wave
passes south over the area in northwest flow aloft. Instability shwrs
again look possible across the eastern zones and have added a slgt
chc mention for now.
Beyond this...a period of dry weather can be expected through the
duration of the work week as a strong omega block develops across the
Nation`s Heartland. From this vantage point...hard to believe much in
the way of any significant precip can be expected through the start
of next weekend as riding takes up position directly over the Plains.
With heights building aloft...expect a warming trend with mid/upper
70s likely both Saturday and Sunday. Along with the warmer
temps...latest model runs hint the strong ridge will begin to
breakdown by Saturday as weak shortwave energy begins sliding through
the upper Miss Vly. This could result in developing shwrs/storms
both Saturday afternoon and Sunday.
&&
.Aviation...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 627 PM CDT SAT APR 30 2016
VFR conds will prevail thru tonight will sct-bkn cigs around 4kft.
Tomorrow morning a sfc trof will sink thru the terminals bringing
MVFR cigs btn 1-2kft. The NAM also suggests the potential for fog
reducing vsbys to 1-2SM however, it is the only model that does so.
Consequently, have kept fog formation out of the TAF at this time
but will continue to monitor. MVFR cigs will lift to 2-3kft around
17Z-19Z with the potential for further lifting to low-end VFR by the
end of the TAF pd. Winds will be out of the west blw 10kts thru
tomorrow morning before veering to the NW around 10kts tomorrow
afternoon.
&&
.EAX Watches/Warnings/Advisories...
KS...None.
MO...None.
&&
$$
Discussion...32
Aviation...73
Area Forecast Discussion
National Weather Service Springfield MO
1156 PM CDT SAT APR 30 2016
.SHORT TERM...(This evening through Sunday)
Issued at 228 PM CDT Sat Apr 30 2016
Dryline currently moving across the forecast area this afternoon
is expected to spark storms that will affect mainly the eastern
Ozarks through this evening. A few strong to severe storms will be
possible through early evening as mentioned in the previous
mesoscale discussion.
Otherwise expect sky cover to continue clearing from west to
east as drier airmass behind the cold front spreads across the
area and main area of low pressure over the central Plains pushes
eastward toward the Ohio Valley. Temperatures are expected to drop
into the 40s over the western Ozarks and southeast Kansas tonight.
Still looks like we will have temperatures about 10 to 15 degrees
cooler on Sunday.
.LONG TERM...(Sunday Night through Saturday)
Issued at 228 PM CDT Sat Apr 30 2016
Models have increased the coverage of precipitation associated
with passage of upper level trough axis on Monday/Monday night...but
continue to keep accumulations low. Instability is low to nil so
will keep thunder out of the forecast.
The rest of the work week looks dry as high pressure builds
across the region and upper ridge sets up across the
Rockies. There may be some increase in cloud cover Wednesday night
as a weak disturbance drops southeast around the back side of the Great
Lakes upper trough.
Storm activity may pick up late next weekend as an upper level
trough develops over the southwest U.S.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1145 PM CDT Sat Apr 30 2016
Patchy fog is expected late tonight and early Sunday morning as
winds become nearly calm. The fog will be shallow in nature with
visibilities being highly variable.
Any fog will then dissipate by mid-morning on Sunday with VFR
expected into the evening. Winds will be light out of the west on
Sunday.
&&
.SGF Watches/Warnings/Advisories...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Terry
LONG TERM...Terry
AVIATION...Schaumann
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1128 PM CDT SAT APR 30 2016
.UPDATE...
Issued at 901 PM CDT Sat Apr 30 2016
Watch has been expanded into south central Illinois ahead of the
current line. There is some threat for severe weather over the
next hour across south central Illinois into southeast Missouri.
Because of this, the watch has also been extended until 10 pm.
Overall threat for severe weather is expected to gradually
diminish however in the next hour or two as instability will be
diminishing with the loss of daytime heating.
Britt
&&
.SHORT TERM... (Through Late Tonight)
Issued at 314 PM CDT Sat Apr 30 2016
There remains the potential for a few severe thunderstorms to
develop late this afternoon and early this evening along and south
of a warm front that lies from west northwest to east southeast
across the area. Clearing over western Missouri has allowed SBCAPEs
to climb into the 1000-2000+ J/kg range. The RAP still suggests
this instability will move eastward into east central and southeast
MO as well as southern IL by late this afternoon and this evening.
Deep layer shear still support organized severe thunderstorms
capable of producing some severe sized hail and locally damaging
winds. The experimental HRRR reflectivity suggests that these
storms will move out of the CWA by mid evening. MOS guidance also
suggest there may be some patchy fog developing after midnight
across the area.
Britt
.LONG TERM... (Sunday through Next Saturday)
Issued at 314 PM CDT Sat Apr 30 2016
(Sunday through Tuesday)
Upper low will move across Iowa on Sunday bringing a weak shortwave
trough across the area. Will keep chance of showers and isolated
thunderstorms going along and north of I-70 as it passes through.
Sunday night still looks mainly dry before both the GFS/ECMWF brings
another shortwave trough through the area on Monday. Will go with
just a slight chance of showers across much of the area with this
trough. Northwesterly upper flow will set up over the area by
Tuesday with westerly surface winds, so will keep with a dry
forecast.
Temperatures will be slightly cooler on Sunday, and then even cooler
on Monday as cold air advects into the area under cloudy skies.
Temperatures should begin to moderate on Tuesday ahead of a cold
front as winds turn out of the west.
(Wednesday through Saturday)
Highly amplified upper flow will continue during the middle and end
of the next week as an omega block sets up over North America. We
will stay under northwesterly flow aloft during most of this period
with the upper ridge of the omega block approaching from the west by
Saturday. GFS and ECMWF are in decent agreement that a cold front
will move through the area on Wednesday with just a slight chance of
showers. Temperatures behind the front will be near normal with
850mb temperatures in the 5-10C range until they begin to warm up
by next Saturday.
Britt
&&
.AVIATION... (For the 06z TAFs through 06z Sunday Night)
Issued at 1101 PM CDT Sat Apr 30 2016
A cold front extends from a surface low near PPQ south-southwest
through southwestern AR. Scattered showers and thunderstorms
should move out of the St Louis metro area by 06Z Sunday. With
light surface winds and recent rainfall, patchy fog should develop
late tonight in the St Louis metro area and also possibly in COU
as well. Stratus clouds below 1000 feet along with visibilities
below 1SM in fog will likely continue late tonight and early
Sunday morning in UIN. Fog will gradually dissipate by late Sunday
morning with ceilings rising into the MVFR catagory by afternoon
at UIN. Scattered-broken diurnal cumulus clouds should develop
late Sunday morning and afternoon with widely scattered showers
possible in UIN during the afternoon ahead of an upper level
disturbance. Surface winds should be mainly w-nwly on Sunday with
a surface ridge building into the area from the Plains.
Specifics for KSTL: Showers and thunderstorms will likely move out
of the STL area by 06Z Sunday. Light fog can be expected late
tonight and early Sunday morning as the wind becomes light.
Scattered to broken diurnal cumulus clouds will develop late
Sunday morning and afternoon with a w-nwly surface wind. The cloud
ceiling may lower into the MVFR catagory late Sunday night.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
350 AM CDT SUN MAY 1 2016
.SYNOPSIS...
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM CONTINUES TO SLOWLY PUSH ACROSS SOUTHEASTERN
NEBRASKA THIS MORNING. DEFORMATION BAND STRETCHES ACROSS NORTH
CENTRAL INTO SOUTHWEST NEBRASKA. PRECIP TYPE GENERALLY RAIN EAST OF
HIGHWAY 83 THEN A MIX OR A CHANGE TO ALL SNOW TO THE WEST OF 83.
TEMPS HAVE HELD FAIRLY STEADY MOST OF THE NIGHT IN THE MID 30S TO
AROUND 40...HOWEVER THE LAST HOUR HAS SEEN A RISE OF A DEGREE IN A
FEW SPOTS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM WILL FINALLY PUSH FAR ENOUGH TO THE EAST THAT AN
END TO THE RAIN/SNOW IS EXPECTED TODAY. THE BAND HAS BECOME MORE
BROKEN OVERNIGHT...WITH THIS TREND EXPECTED TO CONTINUE THROUGH THE
MORNING HOURS. MOST MODELS HAVE THE CWA DRY FOR THE AFTN...HOWEVER
THE LATEST HRRR KEEPS THE EASTERN ZONES IN LIGHT SHOWERS INTO THE
AFTERNOON HOURS. CURRENT THINKING IS THE DRY AIR FROM THE NORTH WILL
GET DRAWN INTO THE AREA...ALONG WITH RISING TEMPS DUE TO DAYTIME
HEATING AND WARM AIR ADVECTION FROM DEPARTING LOW...WITH THE
FORECAST PRIMARILY DRY. WITH TEMPS ALREADY STARTING TO RISE...EXPECT
THE THREAT FOR SNOW TO QUICKLY END WITH LIQUID PRECIP TO BE THE
PREDOMINATE P-TYPE. WILL HAVE TO MONITOR FOR THE AFTERNOON AS SOME
ISOLATED SPRINKLES/LIGHT RAIN SHOWERS CAN NOT BE RULED OUT.
CLOUDS LINGERING THROUGH THE DAY AND WILL LIMIT HEATING. HAVE GONE
WITH THE COOLER GUIDANCE AS MOST GUIDANCE HAS BEEN TOO WARM THE PAST
FEW DAYS. BY TONIGHT DECREASING CLOUDS COMBINE WITH LIGHT WINDS FOR
A GOOD SET UP FOR RADIATIONAL COOLING. TEMPS LIKELY TO DIP BELOW
FREEZING FOR MOST WESTERN LOCATIONS. STILL A LITTLE EARLY FOR ANY
FROST HEADLINES...AND MANY LOCATIONS WITH THE COOLER TEMPS
EXPECTED...JUST SAW ACCUMULATING SNOWS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN MAY 1 2016
MID RANGE...MONDAY AND TUESDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION. IN THE WAKE OF THE CLOSED LOW THAT
BROUGHT PERSISTENT RAIN AND SNOW TO THE AREA... A SHORTWAVE WILL
TRAVERSE THE SANDHILLS LATE MONDAY.
MONDAY... MADE LITTLE CHANGE TO MAX TEMPS EXCEPT FOR COOLED THE
SOUTHWEST CORNER NEAR COLORADO TO ACCOUNT FOR POSSIBLE REMAINING
SNOW PACK. CURRENT FORECAST HIGHS ARE SLIGHTLY BELOW MOS GUIDANCE...
BUT INCREASING CLOUD COVER WITH THE SHORTWAVE MAY HELP OFFSET WAA.
WITH BETTER AGREEMENT AMONG THE MODELS REGARDING THE WAVE AND MID
LEVEL FRONTOGENESIS... INTRODUCED SCHC POPS BEGINNING 18Z. NAM KEEPS
THE AREA DRY DUE TO OVERALL LACK OF MOISTURE AND LIFT. GFS AND EURO
ARE MORE BULLISH WITH THE MOISTURE AND DEPICT AN AREA OF 500-700HPA
SATURATION OVER THE CWA LATE MONDAY. LIFT IS STILL RATHER WEAK IN
GFS SOUNDINGS... BUT MOISTURE AND FGEN MAY BE STRONG ENOUGH IN THE
MID LEVELS TO OVERCOME RELATIVELY DRY AIR NEAR THE SURFACE.
TUESDAY... SHUT OFF POPS BY 12Z ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA AS THE WAVE IS FAIRLY QUICK PASSING. SWITCHED PTYPE TO
RASN WEST OF NEB HWY 61 WHERE HIGHER ELEVATION AND COOLER LOW TEMPS
WOULD SUPPORT A MIX. AS THIS LOOKS LIKE A LIGHT PRECIP EVENT AT
MOST... SHOULD NOT BE ADEQUATE DYNAMIC COOLING TO RESULT IN ALL SNOW
AND THUS KEPT SNOW AMOUNTS AT ZERO. DID PUSH MAX TEMPS UP A
DEGREE... WHICH LEANS TOWARD MAV AND MET. SKY SHOULD CLEAR OUT
QUICKLY BEHIND THE SHORTWAVE... AND MODELS ARE CONSISTENT WITH
NOTICEABLE WAA ACROSS THE REGION. GFS AND NAM BRING H85 TEMPS TO 11C
NORTH CENTRAL AND 14C FAR WEST. PLENTY OF DRY AIR ALOFT WILL ALLOW
FOR UNINHIBITED MIXING TO NEAR 700HPA... AND WITH A SLIGHT DOWNSLOPE
COMPONENT AT 850HPA... HIGHS SHOULD BE ABLE TO REACH NEAR 70F.
LONG RANGE...WEDNESDAY THROUGH SATURDAY... THIS PERIOD IS DOMINATED
BY A BLOCKING PATTERN ALOFT... RESULTING IN AN AMPLIFIED RIDGE OVER
THE GREAT PLAINS. WEAK WAA AND DRY WEATHER CONTINUE THROUGHOUT THE
WEEK WITH HIGHS IN THE LOWER/MID 70S. MOISTURE ADVECTION REALLY
TAKES SHAPE LATE WEEK AS LOW LEVEL FLOW TURNS SOUTHERLY. GFS AND
EURO ARE PUSHING SFC DEW POINTS INTO THE LOWER 50S ALONG/EAST OF HWY
83 THURSDAY PM AND MID/UPPER 50S FRIDAY PM. BOTH MODELS HAVE A LOW
LEVEL JET DEVELOPING FRIDAY NIGHT. THE BRUNT OF THE SPEED
CONVERGENCE IS OVER THE SANDHILLS... SO FELT CONFIDENT ENOUGH TO
RETAIN CHC POPS OVERNIGHT. THE WESTERN CLOSED LOW REACHES THE
SOUTHWEST DESERT SATURDAY... WHICH BEGINS THE RIDGE BREAKDOWN PHASE
FOR WESTERN NEBRASKA. THE H3 JET FEATURES A 100+KT STREAK POINTED
TOWARD EASTERN COLORADO SATURDAY PM... AND WITH DEW POINTS NOW
PUSHING 60F... THUNDERSTORMS ARE A DISTINCT POSSIBILITY. GFS AND
EURO ARE IN SURPRISINGLY GOOD AGREEMENT WITH THE SFC LOW NEAR KSNY
AND H5 LOW OVER KLAS 00Z SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM CDT SAT APR 30 2016
FOR THE KLBF TERMINAL...THE THREAT FOR RAIN OR SNOW WILL CONTINUE
INTO THE OVERNIGHT HOURS. CIGS WILL RANGE FROM 2000 TO 4000 FT AGL
WITH THE LOWER CIGS OCCURRING WITH THE ONSET OF PCPN. BY
DAYBREAK...CIGS WILL GRADUALLY INCREASE TO 3500 TO 5000 FT AGL
SUNDAY MORNING...WITH CLEARING EXPECTED BY SUNDAY EVENING. FOR THE
KVTN TERMINAL...EXPECT CIGS OF 1000 TO 1500 FT AGL OVERNIGHT WITH
LIGHT RAIN POSSIBLE THROUGH 10Z SUNDAY. CIGS WILL INCREASE SUNDAY
MORNING TO 2500 TO 5000 FT AGL...WITH SKIES CLEARING SUNDAY
AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT SUN MAY 1 2016
THE HEAVIEST PRECIPITATION HAS ENDED ACROSS THE CWA WITH ONLY LIGHT
QPF AMOUNTS EXPECTED THIS MORNING. WHILE SO FAR RIVERS HAVE REMAINED
INSIDE THERE BANKS...MANY ARE ON THE RISE. SEVERAL AREA RIVER
FORECAST HAVE INCREASED TO ACTION STAGE...HOWEVER NONE ARE
FORECASTED TO REACH FLOOD STAGE AT THIS TIME. THE SLOW DURATION OF
THE RAINFALL HAS ALLOW MOST OF THE PRECIP TO SOAK INTO THE GROUND.
THIS SATURATED GROUND FROM THE PAST COUPLE OF STORM SYSTEMS HAS
RESULTED IN NUMEROUS FIELDS AND PASTURES TO HAVE POCKETS OF STANDING
WATER. WHILE NO FLOODING IS EXPECTED AT THIS TIME...RIVER RESPONSES
WILL CONTINUED TO BE MONITORED CLOSELY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MASEK
SHORT TERM...MASEK
LONG TERM...SNIVELY
AVIATION...BUTTLER
HYDROLOGY...MASEK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
205 AM EDT SUN MAY 1 2016
.SYNOPSIS...
HIGH PRESSURE TO THE NORTH WILL MAINTAIN A COOL WEDGE ACROSS THE
REGION OVERNIGHT AHEAD OF A WARM FRONT APPROACHING FROM THE SOUTH
LATE. THIS WARM FRONT WILL MOVE NORTH OF THE AREA SUNDAY
AFTERNOON...FOLLOWED BY A COLD FRONT MONDAY. A STRONGER COLD FRONT
WILL THEN MOVE THROUGH THE REGION BY MIDWEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 840 PM EDT SATURDAY...
DEEPER MOISTURE HAS CONTINUED TO SLOWLY INCREASE FROM SW TO NE
THIS EVENING AS BACKING ALOFT OVER THE WEDGE HAS RESULTED IN
PROGRESSIVELY WETTER SOUNDINGS PER PWATS NOW OVER AN INCH. HOWEVER
THE LOW LEVEL CAD REMAINS FIRMLY ENTRENCHED WITH THE EVENING RNK
RAOB SHOWING EASTERLY FLOW UP TO ABOVE 9H WHILE GUIDANCE INDICATES
LITTLE EROSION UNTIL LATE AND MAINLY ACROSS THE SW PERIMETER. THIS
WILL CONTINUE TO SUPPORT BANDS OF CONVECTION DEVELOPING TO THE
SOUTH WITHIN MORE INSTABILITY...AND THEN RIDING OVER THE COOL
POOL IN ELEVATED FASHION OVERNIGHT IN CONJUNCTION WITH MORE ISENTROPIC
LIFT NATURE LIGHT RAIN FARTHER NORTH. LATEST HRRR SUPPORTS THIS
TREND OVER THE NEXT FEW HOURS WITH ANY CONVECTION WEAKENING BEFORE
RAMPING UP DURING THE EARLY MORNING HOURS WHEN THE WARM FRONT TO
THE SOUTH GETS CLOSER AND MOISTURE CONVERGENCE ENHANCES. APPEARS
COULD BE A COUPLE ROUNDS OF HEAVIER SHOWERS WITH ISOLATED TSRA
POSSIBLE MAINLY SOUTH/WEST AS WARMING ALOFT DEEPENS A BIT BUT
STILL UNCERTAINTY WITH THE DEGREE OF ANY PROLONGED HEAVY RAIN.
THUS WONT HOIST ANY FLOOD WATCHES ESPCLY GIVEN LIGHTER TOTALS SO
FAR AND LITTLE OUT EAST WHERE THE DEEPER WEDGE CONTINUES TO LIMIT
PRECIP. OTRW HAVE AGAIN TRENDED POPS LOWER EAST OF THE BLUE RIDGE
TO INIT BEFORE INCREASING TO LIKELY/CATEGORICAL OVERNIGHT AS
DEEPER MOISTURE FINALLY NUDGES EAST. FOG ALSO REMAINS AN ISSUE
ALONG THE BLUE RIDGE BUT WITH RAIN INCREASING EXPECTING SOME
IMPROVEMENT FROM SW TO NE. THUS STAYING WITH THE GOING SPS FOR
AREAS OF DENSE FOG WITHOUT HEADLINES FOR NOW. LOWERED TEMPS A
LITTLE MORE GIVEN CONTINUED LOW LEVEL COOL ADVECTION AND LIGHT
RAIN/DRIZZLE THROUGH THE COLUMN WHICH HAS COOLED MOST BACK INTO
THE CHILLY/DAMP LOW/MID 50S THIS EVENING.
UPDATE AS OF 620 PM EDT SATURDAY...
WITH THE MAJORITY OF THE MEASURABLE RAINFALL MAINLY ACROSS THE FAR
NW AND EXTREME SW SECTIONS...UPDATED TO LOWER POPS BACK TO CHANCE
ELSEWHERE FOR A COUPLE HOURS INTO THIS EVENING. APPEARS MOST
SIGNIFICANT RAINFALL WILL OCCUR OVER THE NW NC MOUNTAINS/FOOTHILLS
WHERE CONVECTION DEVELOPING IN A MORE UNSTABLE ENVIRONMENT TO THE
SW PUSHES INTO/OVER THE WESTERN PERIPHERY OF THE WEDGE OVER THE
NEXT FEW HOURS. THIS WARM ADVECTION HAS ALSO CAUSED CLOUD BASES TO
LOWER ALLOWING FOR MORE WIDESPREAD DENSE FOG ALONG PARTS OF THE
SOUTHERN BLUE RIDGE. THIS TREND MAY DEVELOP FARTHER NORTH AS WARM
AIR ALOFT DEEPENS OVER THE WEDGE AND AIDED BY SATURATED LOW LEVELS
PER RAINFALL. ALSO LOWERING LOW TEMPS A FEW DEGREES MOST LOCATIONS
SINCE CLOSE TO CURRENT FORECAST VALUES OVERNIGHT ALTHOUGH NOT
EXPECTING VALUES TO FALL MUCH MORE AS RAINFALL INCREASES.
PREVIOUS DISCUSSION AS OF 330 PM EDT SATURDAY...
STRONG WEDGE IN PLACE THIS AFTERNOON WILL HOLD AS WE HEAD THRU THE
NIGHT. MEANWHILE...UPPER LEVEL DIVERGENCE AHEAD OF SHORTWAVE WILL
SET UP ACROSS THE CENTRAL AND SOUTHERN APPALACHIANS THIS EVENING
WITH RAINFALL OVERSPREADING THE MOUNTAINS. LOOKING AT OVERNIGHT WE
START TO SEE MODELS EMPHASIZE STRONG LOW LVL CONVERGENCE WITH UPPER
DIVERGENCE ACROSS THE SOUTHERN CWA...WITH ENHANCED RAINFALL AMOUNTS
IN THE SOUTHERN APPALACHIANS. ATTM...LOOKS LIKE AT LEAST MOST OF THE
AREA WILL SEE RAIN OVERNIGHT WITH ONE HALF TO THREE QUARTERS OF AN
INCH SETTING UP ACROSS THE SOUTHERN BLUE RIDGE. WILL NOT ISSUE A
FLOOD WATCH AT THIS POINT...BUT WILL BEAR MONITORING TO SEE IF ANY
DEEP CONVECTION DEVELOPS AND TRAINS ACROSS THIS AREA LATE TONIGHT.
WILL MAINTAIN ISOLATED FLOOD THREAT IN THE HWO.
AS FAR AS THUNDERSTORMS...AM KEEPING THEM OUT OF THE FORECAST
THROUGH TONIGHT GIVEN LACK OF INSTABILITY AND WEDGE. AS WE HEAD TO
SUNDAY WILL BE HARD PRESSED TO CLEAR SKIES IN THE NORTH AND EAST BUT
MODELS FAVOR QUICKER EROSION OF THE WEDGE. WILL BE SLOWER...THEN
INTRODUCE A CHANCE OF STORMS IN THE AFTERNOON. SPC CONTINUES TO
HIGHLIGHT MARGINAL RISK FOR MOST OF THE CENTRAL AND SOUTHERN
APPALACHIANS INTO THE PIEDMONTS OF NC/VA. QUESTION WILL BE IF
SUNSHINE CAN BREAK OUT. AT THE MOMENT SEEMS BEST CHANCE OF THIS WILL
BE IN WV/FAR SW VA AND ACROSS THE NW NC PIEDMONT...BUT THINK CLOUDS
WILL BE AROUND MOST OF THE DAY.
WITH FLOW TURNING SSW BY AFTERNOON WENT CLOSE TO MOS ON HIGHS...BUT
COULD SEE IT COOLER IN LYH TO HSP. MOST WILL SEE HIGHS IN THE LOWER
TO MID 70S.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
AS OF 230 PM EDT SATURDAY...
A WEAK WAVE OF LOW PRESSURE WILL BE TRACKING NORTHEAST FROM THE OHIO
VALLEY TOWARD NEW ENGLAND OVERNIGHT SUNDAY DRAGGING A COLD FRONT
SLOWLY ACROSS THE REGION EARLY MONDAY. CHANCES FOR SHOWERS OVERNIGHT
WILL BE DECREASING DURING THE DAY AND SHOULD SEE SOME PARTIAL
CLEARING ESPECIALLY EAST OF THE MOUNTAINS LATER IN THE DAY. EXPECT
MILD TEMPS BEHIND THE FRONT ON MONDAY RANGING FROM NEAR 70 NORTHWEST
TO LOW 80S SOUTHEAST AS COOLING IS MODEST BEHIND IT..H85 TEMPS
DROPPING ONLY A FEW DEGREES BY LATE IN THE DAY. THIS BOUNDARY MAKES
ONLY SLIGHT PROGRESS TO THE SOUTHEAST BY LATE MONDAY LEAVING ENOUGH
CLOUDS TO HOLD TEMPS UP SOMEWHAT HIGHER MONDAY NIGHT...GENERALLY
UPPER 40S TO MID-50S. THE SAME FRONT WILL BECOME NEAR STATIONARY
ALONG COAST AND BECOME THE FOCUS FOR SHOWERS AND POSSIBLY SOME
THUNDERSTORMS ON TUESDAY AS SEVERAL WEAK WAVES TRAVERSE NORTHEAST
ALONG IT. MODELS DIFFER IN THE PLACEMENT OF THIS BOUNDARY STRENGTH
OF PERTURBATIONS ALONG IT WHICH WILL HAVE A SUBSTANTIAL IMPACT ON
PRECIPITATION CHANCES ON TUESDAY. WPC AND GFS SOLUTIONS CURRENTLY
FURTHER SOUTHEAST THAN EARLIER CMC OR ECMWF RUNS WHICH BOTH BRING
CONSIDERABLY MORE CLOUDS AND SHOWERS INTO OUR CWA. WENT WITH A MODEL
BLEND RETAINING CHANCE POPS ACROSS THE ENTIRE CWA BUT THE HIGHEST
OVER THE SOUTHEAST.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 230 PM EST SATURDAY...
LOW PRESSURE WILL CONTINUE TO LINGER ALONG THE SOUTHEAST COAST EARLY
WEDNESDAY WITH ASSOCIATED CLOUDS AND SHOWERS MAINLY CONFINED TO THE
COASTAL PLAIN AND EASTERN PIEDMONT DURING THE DAY BUT STILL
LINGERING POPS ACROSS OUR CWA BUT MAINLY SOUTHEAST. TEMPS WILL
REMAIN NEAR SEASONAL LEVELS WEDNESDAY WITH PARTIAL CLEARING DURING
IN THE DAY ESPECIALLY NORTHWEST. MEANWHILE ANOTHER FRONT OVER THE
UPPER PLAINS BEGINS TO DROP SOUTHEAST TOWARD THE AREA LATE WEDNESDAY
INTO THURSDAY AS NORTHERN STREAM TROUGH BEGINS TO AMPLIFY
SHARPLY.BOTH GFS AND EURO SHOW UPPER LOW CLOSING OVER THE EASTERN
CONUS BY LATE THURSDAY WITH EXACT POSITION UNCERTAIN AND LIKELY TO
HAVE CONSEQUENCES FOR SENSIBLE WEATHER BY THAT TIME. 00Z EURO IS THE
MOST AGGRESSIVE WITH DEEP COMPLEX SURFACE LOW MORE OR LESS MERGING
WITH THE EXISTING COASTAL SYSTEM AND ACTUALLY BACKING IN TOWARD THE
MID-ATLANTIC COAST. GFS/CMC NOT QUITE AS FAR SOUTH AND DEEP WITH
UPPER TROUGH AND SURFACE REFLECTION WHICH SEEMS MORE
CLIMATOLOGICALLY PLAUSIBLE BUT WENT WITH BLEND TO ACCOUNT FOR
SIGNIFICANT UNCERTAINTY. EITHER WAY A PERSISTENT DEEP NORTHWEST FLOW
WILL EXIST FRIDAY INTO SATURDAY WITH COOL TEMPS AND PLENTY OF CLOUDS
ESPECIALLY ACROSS THE MOUNTAINS. HIGHS FRIDAY WILL STRUGGLE TO REACH
60 OVER THE MOUNTAINS...CLOSE TO 10F BELOW NORMAL. SLOWLY RISING
HEIGHTS SATURDAY WILL ALLOW FOR SLOWLY IMPROVING CONDITIONS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 200 AM EDT SUNDAY...
A STRONG COOL WEDGE WILL PERSIST THROUGH THE REMAINDER OF THE
NIGHT...AND KEEP CEILINGS AT LIFR/IFR WITH VISIBILITIES AT MVFR.
ALTHOUGH THERE COULD BE MOMENTS WHERE THE CEILINGS AND
VISIBILITIES TEMPORARILY IMPROVE...THE OVERALL TREND SUGGESTS A
DETERIORATION OF FLYING CONDITIONS. PERIODS OF RAIN AND FOG
SHOULD ALSO CONTINUE...AS MOISTURE KEEPS INCREASING AHEAD OF AN
APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTHERN PLAINS. MODEL
SOUNDINGS SHOW AN INTENSIFYING LOW LEVEL JET AHEAD OF THIS SYSTEM
THAT COULD BRING LOW LEVEL WIND SHEAR FOR ALL SITES DURING EARLY
SUNDAY MORNING.
NOT MUCH CHANGE WILL TAKE PLACE AS THE MORNING PROGRESSES...WITH
PERIODS OF RAIN AND LIFR/IFR CEILINGS ONGOING. BY SUNDAY
AFTERNOON...CEILINGS EVENTUALLY IMPROVE TO MVFR/IFR ONCE THE COOL
WEDGE BEGINS TO ERODE...ALTHOUGH KLYH MAY BE LAST TO BREAK OUT OF
THE WEDGE. SCATTERED SHOWERS AND THUNDERSTORMS COULD DEVELOP WEST
OF THE WEDGE BOUNDARY...AND THE POTENTIAL EXISTS FOR SCATTERED
STRONG TO SEVERE STORMS IF ENOUGH SUNSHINE DESTABILIZES THE
ATMOSPHERE. HOWEVER...CONFIDENCE IS TOO LOW TO PINPOINT WHICH
SITES WILL SEE THUNDER AT THIS MOMENT TO ADVERTISE IT IN THE TAFS.
THE THREAT OF SHOWERS AND THUNDERSTORMS SHOULD CEASE AFTER SUNSET.
EXTENDED AVIATION DISCUSSION...
THE AFOREMENTIONED LOW PRESSURE SYSTEM SHOULD CROSS OVER THE MID
ATLANTIC DURING SUNDAY NIGHT...BUT THE BOUNDARY WILL STALL
OVERHEAD BY MONDAY. MORE WAVES OF LOW PRESSURE WILL MOVE ALONG
THE STALLED BOUNDARY FROM TUESDAY THROUGH THURSDAY...WHICH SHOULD
HELP PUSH THE BOUNDARY OFFSHORE. A DEEP UPPER LEVEL TROUGH IS
PROJECTED TO DIVE SOUTHWARD OVER THE APPALACHIAN MOUNTAINS BY
WEDNESDAY INTO THURSDAY. OVERALL...FLYING CONDITIONS APPEAR RATHER
POOR THROUGH MOST OF THIS WEEK DUE TO THE LIKELIHOOD OF LOW
CLOUDS...PERIODS OF RAIN...AND PATCHY FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/WP
SHORT TERM...PC
LONG TERM...PC
AVIATION...PW
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
845 AM MST SUN MAY 1 2016
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL LINGER OVER THE REGION THROUGH TONIGHT...
PROVIDING BELOW NORMAL TEMPERATURES...AND A CHANCE OF SHOWERS AND
THUNDERSTORMS OVER NORTHERN AND EASTERN ARIZONA. A HIGH PRESSURE
SYSTEM WILL SUBSEQUENTLY REBUILD OVER THE REGION MONDAY THROUGH
THURSDAY...RESULTING IN MOSTLY CLEAR SKIES AND A STRONG WARMING
TREND. ANOTHER PACIFIC WEATHER SYSTEM HOWEVER IS FORECAST TO MOVE
INTO THE AREA NEXT FRIDAY AND THE WEEKEND...BRINGING COOLER
TEMPERATURES...BREEZY CONDITIONS...AND A SLIGHT CHANCE OF SHOWERS.
&&
.DISCUSSION...
A RATHER COOL MORNING...FOR THE 1ST OF MAY ACROSS OUR CWA THIS
MORNING. MOST LOWER DESERT LOCATIONS SAW LOWS IN THE UPPER 50-LOW 60
RANGE...WITH SKY HARBOR SEEING A LOW OF 59...6 DEGREES BELOW THE
NORMAL FOR THE DATE. THE UPPER LOW THAT BROUGHT US THIS COOL
WEATHER...AND THE RAINFALL YESTERDAY/LAST NIGHT IS NOW MOVING
EASTWARD ACROSS EAST-CENTRAL AZ AND IS EXPECTED TO MOVE INTO THE 4-
CORNERS REGION BY THIS EVENING. TO THE SOUTH AND WEST OF THIS LOW
CENTER...TEMPERATURES ALOFT ARE BEGINNING TO WARM...STABILIZING THE
ATMOSPHERE AND ENDING THE SHOWER ACTIVITY ACROSS MOST OF OUR CWA.
HOWEVER...LEFT-OVER MOISTURE ROTATING AROUND THE BACK SIDE OF THE
UPPER LOW CENTER IS STILL TRIGGERING A FEW SHOWERS OVER PINAL AND
SOUTHERN GILA COUNTIES...AS WELL AS EXTREME EASTERN MARICOPA COUNTY
AT THIS HOUR. THE LATEST HRRR HIGH-RES MODEL RUN IS SHOWING THESE
SHOWERS CONTINUING THROUGH ABOUT MIDDAY BEFORE DIMINISHING THIS
AFTERNOON. GIVEN THESE CURRENT TRENDS...IT APPEARS THAT OUR CURRENT
SHORT-TERM FORECASTS ARE HOLDING UP WELL..AND NO UPDATES ARE PLANNED
AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
TODAY AND TONIGHT...
THE COOL LOW PRESSURE SYSTEM OVER AZ WILL LINGER OVER THE STATE
TODAY...ALBEIT MOVE SLOWLY TO THE EAST BY EARLY AFTERNOON. MODELS
FORECAST THE 500 MB CIRCULATION CENTER TO MOVE FROM OVER PHOENIX
EARLY THIS MORNING...TOWARD THE WHITE MOUNTAINS IN EAST CENTRAL AZ
BY AFTERNOON. THEREFORE A FEW LIGHT SHOWERS ARE POSSIBLE OVER THE
DESERTS NEAR PHOENIX THIS MORNING...CHANGING TO A SLIGHT CHANCE OF
SHOWERS DURING THE AFTERNOON WITH INCREASING STABILITY. MOSTLY
CLOUDY SKIES HOWEVER ARE FORECAST OVER MUCH OF SOUTHWEST AND SOUTH
CENTRAL ARIZONA TODAY...WITH THE BEST CHANCE OF SHOWERS AND
THUNDERSTORMS IN OUR MOUNTAINOUS ZONE 24 SOUTHERN GILA COUNTY
THROUGH EVENING. CLEARING TO PARTIAL CLEARING SKIES ARE EXPECTED
EARLY THIS EVENING WITH SHOWERS ENDING.
MONDAY THROUGH THURSDAY...
A HIGH PRESSURE SYSTEM WILL SLOWLY BUILD OVER THE REGION THIS PERIOD
PROVIDING MOSTLY CLEAR SKIES AND MUCH WARMER AFTERNOON TEMPERATURES.
BACK MIDDLE 90S ON THE LOWER DESERTS AGAIN...OR ABOUT 5 DEGREES ABOVE
NORMAL.
THURSDAY NIGHT THROUGH SUNDAY...
MODELS HAVE BEEN FORECASTING ANOTHER PACIFIC WEATHER SYSTEM TO
APPROACH SOUTHERN CA AND AZ LATE THURSDAY AND FRIDAY. ENSEMBLE
MEMBER SPREAD APPEARS TO BE CONSOLIDATING MORE...INCREASING OUR
CONFIDENCE THAT THIS NEW WEATHER SYSTEM WILL BODILY MOVE INTO THE
REGION FRIDAY AND THE WEEKEND. SINCE ENSEMBLE MEMBERS ARE COMING
INTO CLOSER AGREEMENT...WE CAN PLACE SOME VALUE IN THE OPERATION GFS
WHICH SHOWS THIS SYSTEM TO BE INITIALLY DRY FRIDAY AND SATURDAY...
WITH PERHAPS A BETTER CHANCE OF PRECIP SUNDAY. THEREFORE A BROAD
BRUSH FORECAST APPROACH SEEMS TO BE IN ORDER FOR NOW...KEEPING A
SLIGHT CHANCE OF SHOWERS GOING...AND MUCH COOLER TEMPERATURES
DEVELOPING.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
UPPER LOW WILL BEGIN TO WEAKEN AND MAKE A SLOW EXIT TO THE EAST OVER
AZ TODAY. LIGHT RAIN SHOWER ACTIVITY WILL BE POSSIBLE DURING THE
MORNING FROM MARICOPA COUNTY EASTWARD BEFORE PRECIP ACTIVITY FOCUSES
ON THE MOUNTAINS NORTH/EAST OF PHOENIX. SCT TO BKN CLOUDS RANGING 8
TO 12KFT WILL PERSIST THROUGH EARLY AFTERNOON BEFORE DISSIPATING AND
EVENTUALLY CLEARING COMPLETELY AFTER SUNSET. TYPICAL EASTERLY AM
WINDS WILL TRANSITION SOUTH THEN WEST MIDDAY INTO THE
AFTERNOON...WITH GENERALLY LIGHT SPEEDS 6 KTS OR LESS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
FOCUS OF ANY LINGERING PRECIP ACTIVITY TODAY WILL BE WELL EAST OF THE
CO RIVER VALLEY. NOTICEABLY LIGHTER WINDS IN STORE TODAY WITH
HEADINGS VARIANT BETWEEN WEST AND NORTHWEST FOR KIPL AND NORTH AND
NORTHEAST FOR KBLH. FEW TO SCT CLOUDS GNLY AOA 10KFT WILL DISSIPATE
DURING THE DAY...WITH CLEAR SKIES POSSIBLE BY THE AFTERNOON AND FOR
THE EVENING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
HIGH PRESSURE WILL RESULT IN A DRIER AND WARMER AIRMASS OVER THE
DISTRICTS QUICKLY WARMING TEMPERATURES TO ABOVE NORMAL READINGS WITH
MANY LOWER ELEVATION SITES HEADING INTO THE MID TO UPPER 90S. DEEP
PACIFIC TROUGH WILL APPROACH THE WEST COAST MIDWEEK SUPPORTING
INCREASING SOUTHERLY WINDS FOR WEDNESDAY AND THURSDAY. THE
COMBINATION OF STRONG WINDS...PARTICULARLY FOR THURSDAY...AND LOW
HUMIDITIES MAY SUPPORT POCKETS OF CRITICAL FIRE WEATHER CONDITIONS
ACROSS THE LOWER AZ DESERTS. CONDITIONS WILL IMPROVE ON FRIDAY AND
SATURDAY WHEN THE NEXT STORM SYSTEM WILL COOL HIGH TEMPERATURES TO
THE LOW TO MID 80S WITH MINIMUM HUMIDITIES IN THE MID TEEN TO MID 20
PERCENT RANGE BY SATURDAY.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/VASQUEZ
AVIATION...NOLTE
FIRE WEATHER...NOLTE/SAWTELLE
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
844 AM PDT SUN MAY 1 2016
.SYNOPSIS....OFFSHORE WINDS WILL CONTINUE TODAY...RESULTING IN
SUNNY AND WARM CONDITIONS IN MOST AREAS. COASTAL FOG AND LOW
CLOUDS WILL LIKELY RETURN BY LATE TODAY OR TONIGHT. SEASONABLE
AND DRY WEATHER IS FORECAST MONDAY AND TUESDAY. A WEATHER SYSTEM
WILL APPROACH CALIFORNIA BY THE MIDDLE OF THE WEEK...BRINGING A
CHANCE OF SHOWERS FROM LATE WEDNESDAY THROUGH THE END OF THE
WEEK...ALONG WITH COOLER THAN NORMAL TEMPERATURES.
&&
.DISCUSSION...AS OF 8:45 AM PDT SUNDAY...CLEAR START TO THE DAY
WITH A MODERATE OFFSHORE FLOW IN PLACE. N-TO-S GRADIENT RIGHT NOW
IS OVER 2 MB WHILE W-TO-E FLOW IS SLIGHTLY FROM THE EAST. AS THE
PREVIOUS DISCUSSION MENTIONED, MODELS ARE INDICATING A SOUTHERLY
PUSH UP THE COAST TODAY ALTHOUGH CURRENT SATELLITE DOES NOT SHOW
ANY CLOUDS EVEN UP TO SLO COUNTY. 14Z RUN OF THE HRRR DOES
INDICATE SOUTHERLY WINDS WILL SET UP OVER THE NEXT FEW HOURS, SO
WILL KEEP A CLOSE EYE ON THE SATELLITE TO SEE IF IT DOES
MATERIALIZE.
CURRENT FORECAST ON TRACK SO NO UPDATES PLANNED AT THE MOMENT.
.PREVIOUS DISCUSSION...SKIES ARE CLEAR ACROSS OUR ENTIRE FORECAST
AREA EARLY THIS MORNING AS LIGHT OFFSHORE FLOW CONTINUES. CURRENT
TEMPERATURES ARE GENERALLY WARMER THAN 24 HOURS AGO AND IN SOME
CASES SEVERAL DEGREES WARMER. FORECAST GUIDANCE INDICATES HIGH
TEMPERATURES TODAY WILL BE ABOUT FIVE DEGREES WARMER THAN
YESTERDAY. HOWEVER...MODELS FORECAST AN END TO OFFSHORE FLOW TODAY
ALONG WITH THE DEVELOPMENT OF SOUTHERLY FLOW ALONG THE COAST. THIS
DOES NOT LOOK LIKE A CLASSIC "SOUTHERLY SURGE" SCENARIO...SINCE
LOW CLOUDS DO NOT ALREADY EXIST TO OUR SOUTH NEAR POINT
CONCEPTION. WHAT`S MORE LIKELY TO HAPPEN IS THAT LOW CLOUDS AND
FOG WILL FORM IN COASTAL AREAS FROM MONTEREY BAY SOUTH BY EARLY
AFTERNOON...AND THEN MOVE NORTH UP ALONG THE REST OF OUR COAST
LATE THIS AFTERNOON AND EVENING. THIS MAKES FOR A DIFFICULT
TEMPERATURE FORECAST TODAY FOR COASTAL AREAS SINCE THE TIMING OF
THE SOUTHERLY WIND ONSET AND COASTAL FOG DEVELOPMENT WILL HAVE A
BIG IMPACT ON TEMPERATURES. MOST LIKELY SCENARIO IS FOR COOLING TO
OCCUR IN LOCATIONS LIKE BIG SUR AND SANTA CRUZ WHILE OTHER COASTAL
AREAS WILL BE AS WARM OR WARMER THAN YESTERDAY.
ANOTHER ITEM TO WATCH TODAY IS A SHORTWAVE TROUGH CURRENTLY OVER
SOUTHEAST OREGON THAT IS ROTATING AROUND A LONGWAVE TROUGH
CENTERED OVER THE DESERT SW. THIS SHORTWAVE IS FORECAST TO ROTATE
INTO NORTHERN AND CENTRAL CALIFORNIA LATER TODAY. THE ECMWF KEEPS
ALL PRECIP ASSOCIATED WITH THIS SHORTWAVE TO OUR EAST...MAINLY OVER
THE SIERRA NEVADA. HOWEVER...BOTH THE 00Z NAM AND 00Z GFS
FORECAST ISOLATED SHOWERS ALONG THE EASTERN FRINGES OF OUR
FORECAST AREA LATE THIS AFTERNOON AND EARLY THIS EVENING. HAVE
THEREFORE ADDED SLIGHT CHANCE POPS TO FAR EASTERN ALAMEDA...SANTA
CLARA...AND SAN BENITO COUNTIES FOR LATER TODAY.
DRY AND MILD WEATHER IS FORECAST FOR MONDAY AND TUESDAY. ONSHORE
FLOW WILL LIKELY MAINTAIN AT LEAST AREAS OF NIGHT AND MORNING LOW
CLOUDS AND TEMPERATURES WILL BE NEAR NORMAL.
AN UPPER TROUGH CURRENTLY SEEN ON SATELLITE IMAGERY OFFSHORE ALONG
145W IS FORECAST TO GRADUALLY APPROACH THE CALIFORNIA COAST OVER
THE NEXT THREE DAYS AND BEGIN TO GENERATE SHOWER CHANCES ACROSS
OUR AREA BY LATE WEDNESDAY. BOTH THE GFS AND ECMWF FORECAST A
CUTOFF LOW TO DEVELOP NEAR SAN FRANCISCO BY THURSDAY...WITH THAT
LOW THEN PROJECTED TO DROP SOUTHEAST AND TRACK ACROSS SOUTHERN
CALIFORNIA BY LATE FRIDAY AND FRIDAY NIGHT. THUS...SHOWER CHANCES
WILL CONTINUE THROUGH THE END OF THE WEEK AND PROBABLY INTO NEXT
WEEKEND AS WELL. GIVEN THE UNPREDICTABILITY OF CUTOFF LOW
MOVEMENT...IT`S DIFFICULT TO PINPOINT WHERE SHOWER CHANCES WILL BE
GREATEST DURING THE SECOND HALF OF THE WEEK. ISOLATED THUNDERSTORMS
MAY ALSO OCCUR...BUT WILL WAIT TO ADD THUNDERSTORMS TO THE
FORECAST UNTIL CONFIDENCE INCREASES ON THE TIMING AND TRACK OF THE
UPPER LOW. IN ADDITION TO PRECIPITATION CHANCES...THIS UPPER LOW
WILL RESULT IN COOLER THAN NORMAL CONDITIONS ACROSS MOST OF OUR
AREA DURING THE SECOND HALF OF THE WEEK.
&&
.AVIATION...AS OF 4:21 AM PDT SUNDAY...DRY OFFSHORE FLOW KEEPING
MAINLY VFR TODAY. THE ONE FLY IN THE OINTMENT IN THE FORECAST
IS A POSSIBLE SOUTHERLY SURGE LATER TODAY. LATEST NAM AND WRF SHOW
A SOUTHERLY SURGE IMPACTING KMRY/KSNS...POSS MAKING IT INTO SF BAY
OVERNIGHT. CONF IS MARGINAL...BUT WILL ADD CIGS TO MONTEREY BAY.
VICINITY OF KSFO...VFR.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY TERMINALS...VFR WITH SOME HAZE IN THE AM. VFR
BECOMING MVFR THIS EVENING AND OVERNIGHT..
&&
.MARINE...AS OF 8:45 AM PDT SUNDAY...HIGH PRESSURE OVER THE
EASTERN PACIFIC WILL KEEP NORTHERLY WINDS OVER THE COASTAL WATERS
TODAY. LOCALLY GUSTY WINDS WILL BE POSSIBLE OVER THE OUTER WATERS
NORTH OF POINT REYES. SOUTHERLY WINDS WILL DEVELOP LATE TONIGHT
AND EARLY MONDAY. A MODERATE SWELL WILL MIX WITH A SMALLER LONG
PERIOD SOUTHERLY SWELL THIS WEEK.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 9 AM
&&
$$
PUBLIC FORECAST: BELL/DYKEMA
AVIATION: MM
MARINE: MM
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
823 AM MDT SUN MAY 1 2016
.UPDATE...
ISSUED AT 823 AM MDT SUN MAY 1 2016
WEB CAMS INDICATE ACCUMULATING SNOW LEVEL IS SITTING AROUND 6800
FEET ACROSS THE FOUR CORNERS VALLEYS THIS MORNING...BUT IR
SATELLITE SHOWS CLOUD TOPS WARMING AND TEMPERATURES RISING AT
LOCATIONS FROM THE NORTHERN SAN JUANS AND NORTH. WITH THE CORE OF
THE CLOSED LOW SPREADING ACROSS THE SOUTHERN VALLEYS...NOT
EXPECTING SNOW LEVEL TO RISE MUCH OVER THE NEXT COUPLE OF HOURS
OVER THE VALLEYS...BUT FURTHER NORTH THE ACCUMULATING SNOW LEVEL
IS EXPECTED TO BE CLOSER TO 8000 FEET.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
MORE PRECIP IN THE FORECAST TODAY AS THE NEXT AREA OF LOW PRESSURE
CONTINUES TO MOVE TOWARDS THE FOUR CORNERS. AT THIS HOUR...RADAR
MOSAIC ALREADY SHOWING SOME RETURNS JUST TO THE SOUTH OF THE CO/NM
BORDER WHILE IR SATELLITE IS SHOWING ENHANCED CLOUD TOPS OVER THE
SAME REGION. THE HRRR AND RAP13 ARE IN VERY GOOD AGREEMENT WITH
PRECIP BEGINNING FOR THE SOUTHERN VALLEYS JUST BEFORE DAYBREAK
TODAY WITH PRECIP REACHING THE SAN JUANS BETWEEN 7 AND 8 AM. SOME
SNOW ACCUMULATION WILL OCCUR TODAY...MAYBE AS MUCH AS 4 TO 6
INCHES BUT ONLY FOR THE HIGHEST ELEVATIONS. MOUNTAIN PASSES MAY
SEE SOME MINOR ACCUMULATION BEFORE MELTING AS THE DAY MOVES ON.
TOYED WITH IDEA OF ISSUING SOME ADVISORIES BUT A FEW THINGS
STICKING OUT. THE CORE OF THIS LOW PRESSURE CENTER IS RELATIVELY
WARM AT -20C WHILE H7 TEMPS OF -4C AT 6AM WILL WARM TO -1 TO -2C
BY NOON. ALSO...PRECIP LOOKS TO FALL DURING DAYTIME HOURS SO ROAD
SURFACES WILL BE WARM ENOUGH TO MELT MOST SNOW THAT FALLS. IF
NOT...SOME SLUSHY PATCHES CAN BE EXPECTED. THE LAST FEW SYSTEMS
ALSO BROUGHT SNOW TO VARIOUS AREAS OF OUR CWA BUT IMPACTS WERE
MINIMAL. THIS EVENT LOOKS TO BE SIMILAR SO WILL HOLD OFF FOR NOW.
DAY SHIFT CAN KEEP AN EYE ON HOW THINGS TRANSPIRE AND ISSUE A
HIGHLIGHT IF NEEDED/REQUIRED.
BY LATE THIS AFTERNOON...PRECIP WILL HAVE REACHED JUST SOUTH OF
THE I-70 CORRIDOR BUT EXPECT THIS PRECIP TO BE MORE SPOTTY IN
NATURE. BY EARLY MONDAY MORNING...WIDESPREAD RAIN/SNOW LOOKS TO
END AND BECOME MUCH MORE ISOLATED IN NATURE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
A FEW MINOR CHANGES TO THE LONG TERM BUT THE GIST REMAINS THE
SAME. RESIDUAL MOISTURE AND SOME WEAK UPPER LEVEL SUPPORT WILL
LEND ITSELF TO FORM SOME AFTERNOON SHOWERS AND STORMS MONDAY BUT
BY TUESDAY...HIGH PRESSURE BUILDS IN BRINGING A RETURN TO WARMER
CONDITIONS AND SUNNY SKIES. BOTH GFS/NAM PAINT SOME SHOWERS OVER
THE SAN JUANS TUESDAY EVENING BUT THESE WILL LIKELY BE POP AND
DROP SHOWERS OR STORMS THAT WON`T POSE MUCH OF A THREAT. AS THIS
OCCURS...YET ANOTHER LOW PRESSURE MOVES ACROSS CALIFORNIA AND
TAKES AIM AT OUR CWA. A WARM FRONT WILL BRING SOME SHOWERS AND
STORMS TO THE AREA THURSDAY EVENING AHEAD OF THE LOW PRESSURE
SYSTEM. CLOUDS WILL INCREASE THROUGH THE DAY FRIDAY WITH SOME
GUSTY WINDS POSSIBLE DOWN SOUTH BEFORE THE LOW SETS UP OVER THE
CENTRAL GREAT BASIN AND BRINGS MORE PRECIP TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 327 AM MDT SUN MAY 1 2016
FLIGHT CONDITIONS WILL CONTINUE TO DETERIORATE FROM SOUTH TO NORTH
AS THE DAY PROGRESSES WITH RAIN SHOWERS FOR KDRO AND KMTJ AND SOME
SNOW SHOWERS FOR KTEX. MVFR TO IFR IS POSSIBLE UNDER THE HEAVIER
SHOWERS BUT WILL LEAVE OUT OF TAF FOR NOW AS THEY WILL BE ISOLATED
IN NATURE. CONDITIONS WILL ALSO START DROPPING FOR
KASE...KEGE...KRIL AND KGJT TOWARDS THE AFTERNOON AND EVENING
HOURS. CONDITIONS WILL SLOWLY IMPROVE AFTER 06Z TONIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JAM
SHORT TERM...TGR
LONG TERM...TGR
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
427 AM MDT SUN MAY 1 2016
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
MORE PRECIP IN THE FORECAST TODAY AS THE NEXT AREA OF LOW PRESSURE
CONTINUES TO MOVE TOWARDS THE FOUR CORNERS. AT THIS HOUR...RADAR
MOSAIC ALREADY SHOWING SOME RETURNS JUST TO THE SOUTH OF THE CO/NM
BORDER WHILE IR SATELLITE IS SHOWING ENHANCED CLOUD TOPS OVER THE
SAME REGION. THE HRRR AND RAP13 ARE IN VERY GOOD AGREEMENT WITH
PRECIP BEGINNING FOR THE SOUTHERN VALLEYS JUST BEFORE DAYBREAK
TODAY WITH PRECIP REACHING THE SAN JUANS BETWEEN 7 AND 8 AM. SOME
SNOW ACCUMULATION WILL OCCUR TODAY...MAYBE AS MUCH AS 4 TO 6
INCHES BUT ONLY FOR THE HIGHEST ELEVATIONS. MOUNTAIN PASSES MAY
SEE SOME MINOR ACCUMULATION BEFORE MELTING AS THE DAY MOVES ON.
TOYED WITH IDEA OF ISSUING SOME ADVISORIES BUT A FEW THINGS
STICKING OUT. THE CORE OF THIS LOW PRESSURE CENTER IS RELATIVELY
WARM AT -20C WHILE H7 TEMPS OF -4C AT 6AM WILL WARM TO -1 TO -2C
BY NOON. ALSO...PRECIP LOOKS TO FALL DURING DAYTIME HOURS SO ROAD
SURFACES WILL BE WARM ENOUGH TO MELT MOST SNOW THAT FALLS. IF
NOT...SOME SLUSHY PATCHES CAN BE EXPECTED. THE LAST FEW SYSTEMS
ALSO BROUGHT SNOW TO VARIOUS AREAS OF OUR CWA BUT IMPACTS WERE
MINIMAL. THIS EVENT LOOKS TO BE SIMILAR SO WILL HOLD OFF FOR NOW.
DAY SHIFT CAN KEEP AN EYE ON HOW THINGS TRANSPIRE AND ISSUE A
HIGHLIGHT IF NEEDED/REQUIRED.
BY LATE THIS AFTERNOON...PRECIP WILL HAVE REACHED JUST SOUTH OF
THE I-70 CORRIDOR BUT EXPECT THIS PRECIP TO BE MORE SPOTTY IN
NATURE. BY EARLY MONDAY MORNING...WIDESPREAD RAIN/SNOW LOOKS TO
END AND BECOME MUCH MORE ISOLATED IN NATURE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
A FEW MINOR CHANGES TO THE LONG TERM BUT THE GIST REMAINS THE
SAME. RESIDUAL MOISTURE AND SOME WEAK UPPER LEVEL SUPPORT WILL
LEND ITSELF TO FORM SOME AFTERNOON SHOWERS AND STORMS MONDAY BUT
BY TUESDAY...HIGH PRESSURE BUILDS IN BRINGING A RETURN TO WARMER
CONDITIONS AND SUNNY SKIES. BOTH GFS/NAM PAINT SOME SHOWERS OVER
THE SAN JUANS TUESDAY EVENING BUT THESE WILL LIKELY BE POP AND
DROP SHOWERS OR STORMS THAT WON`T POSE MUCH OF A THREAT. AS THIS
OCCURS...YET ANOTHER LOW PRESSURE MOVES ACROSS CALIFORNIA AND
TAKES AIM AT OUR CWA. A WARM FRONT WILL BRING SOME SHOWERS AND
STORMS TO THE AREA THURSDAY EVENING AHEAD OF THE LOW PRESSURE
SYSTEM. CLOUDS WILL INCREASE THROUGH THE DAY FRIDAY WITH SOME
GUSTY WINDS POSSIBLE DOWN SOUTH BEFORE THE LOW SETS UP OVER THE
CENTRAL GREAT BASIN AND BRINGS MORE PRECIP TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 327 AM MDT SUN MAY 1 2016
FLIGHT CONDITIONS WILL CONTINUE TO DETERIORATE FROM SOUTH TO NORTH
AS THE DAY PROGRESSES WITH RAIN SHOWERS FOR KDRO AND KMTJ AND SOME
SNOW SHOWERS FOR KTEX. MVFR TO IFR IS POSSIBLE UNDER THE HEAVIER
SHOWERS BUT WILL LEAVE OUT OF TAF FOR NOW AS THEY WILL BE ISOLATED
IN NATURE. CONDITIONS WILL ALSO START DROPPING FOR
KASE...KEGE...KRIL AND KGJT TOWARDS THE AFTERNOON AND EVENING
HOURS. CONDITIONS WILL SLOWLY IMPROVE AFTER 06Z TONIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...TGR
LONG TERM...TGR
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
411 AM MDT SUN MAY 1 2016
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
MORE PRECIP IN THE FORECAST TODAY AS THE NEXT AREA OF LOW PRESSURE
CONTINUES TO MOVE TOWARDS THE FOUR CORNERS. AT THIS HOUR...RADAR
MOSAIC ALREADY SHOWING SOME RETURNS JUST TO THE SOUTH OF THE CO/NM
BORDER WHILE IR SATELLITE IS SHOWING ENHANCED CLOUD TOPS OVER THE
SAME REGION. THE HRRR AND RAP13 ARE IN VERY GOOD AGREEMENT WITH
PRECIP BEGINNING FOR THE SOUTHERN VALLEYS JUST BEFORE DAYBREAK
TODAY WITH PRECIP REACHING THE SAN JUANS BETWEEN 7 AND 8 AM. SOME
SNOW ACCUMULATION WILL OCCUR TODAY...MAYBE AS MUCH AS 4 TO 6
INCHES BUT ONLY FOR THE HIGHEST ELEVATIONS. MOUNTAIN PASSES MAY
SEE SOME MINOR ACCUMULATION BEFORE MELTING AS THE DAY MOVES ON.
TOYED WITH IDEA OF ISSUING SOME ADVISORIES BUT A FEW THINGS
STICKING OUT. THE CORE OF THIS LOW PRESSURE CENTER IS RELATIVELY
WARM AT -20C WHILE H7 TEMPS OF -4C AT 6AM WILL WARM TO -1 TO -2C
BY NOON. ALSO...PRECIP LOOKS TO FALL DURING DAYTIME HOURS SO ROAD
SURFACES WILL BE WARM ENOUGH TO MELT MOST SNOW THAT FALLS. IF
NOT...SOME SLUSHY PATCHES CAN BE EXPECTED. THE LAST FEW SYSTEMS
ALSO BROUGHT SNOW TO VARIOUS AREAS OF OUR CWA BUT IMPACTS WERE
MINIMAL. THIS EVENT LOOKS TO BE SIMILAR SO WILL HOLD OFF FOR NOW.
DAY SHIFT CAN KEEP AN EYE ON HOW THINGS TRANSPIRE AND ISSUE A
HIGHLIGHT IF NEEDED/REQUIRED.
BY LATE THIS AFTERNOON...PRECIP WILL HAVE REACHED JUST SOUTH OF
THE I-70 CORRIDOR BUT EXPECT MORE THIS PRECIP TO BE MORE SPOTTY IN
NATURE. BY EARLY MONDAY MORNING...WIDESPREAD RAIN/SNOW LOOKS TO
END AND BECOME MUCH MORE ISOLATED IN NATURE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
A FEW MINOR CHANGES TO THE LONG TERM BUT THE GIST REMAINS THE
SAME. RESIDUAL MOISTURE AND SOME WEAK UPPER LEVEL SUPPORT WILL
LEND ITSELF TO FORM SOME AFTERNOON SHOWERS AND STORMS MONDAY BUT
BY TUESDAY...HIGH PRESSURE BUILDS IN BRINGING A RETURN TO WARMER
CONDITIONS AND SUNNY SKIES. BOTH GFS/NAM PAINT SOME SHOWERS OVER
THE SAN JUANS TUESDAY EVENING BUT THESE WILL LIKELY BE POP AND
DROP SHOWERS OR STORMS THAT WON`T POSE MUCH OF A THREAT. AS THIS
OCCURS...YET ANOTHER LOW PRESSURE MOVES ACROSS CALIFORNIA AND
TAKES AIM AT OUR CWA. A WARM FRONT WILL BRING SOME SHOWERS AND
STORMS TO THE AREA THURSDAY EVENING AHEAD OF THE LOW PRESSURE
SYSTEM. CLOUDS WILL INCREASE THROUGH THE DAY FRIDAY WITH SOME
GUSTY WINDS POSSIBLE DOWN SOUTH BEFORE THE LOW SETS UP OVER THE
CENTRAL GREAT BASIN AND BRINGS MORE PRECIP TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 327 AM MDT SUN MAY 1 2016
FLIGHT CONDITIONS WILL CONTINUE TO DETERIORATE FROM SOUTH TO NORTH
AS THE DAY PROGRESSES WITH RAIN SHOWERS FOR KDRO AND KMTJ AND SOME
SNOW SHOWERS FOR KTEX. MVFR TO IFR IS POSSIBLE UNDER THE HEAVIER
SHOWERS BUT WILL LEAVE OUT OF TAF FOR NOW AS THEY WILL BE ISOLATED
IN NATURE. CONDITIONS WILL ALSO START DROPPING FOR
KASE...KEGE...KRIL AND KGJT TOWARDS THE AFTERNOON AND EVENING
HOURS. CONDITIONS WILL SLOWLY IMPROVE AFTER 06Z TONIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...TGR
LONG TERM...TGR
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1150 AM EDT SUN MAY 1 2016
.SYNOPSIS...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A MID/UPPER LAYER
WESTERLY FLOW PATTERN IN PLACE ACROSS THE GULF OF MEXICO AND
FLORIDA PENINSULA. SOUTHERN STREAM JET CROSSES OVER NORTHERN
MEXICO AND ACROSS THE GULF...WITH THE NOSE OF THE MAIN JETSTREAK
OVER OUR REGION. NORTHERN STREAM JET IS IN FAIRLY CLOSE PROXIMITY
TO THE NORTH...CROSSING OVER THE SOUTHERN/CENTRAL PLAINS...TO THE
MID MS AND OHIO VALLEYS. 01/12Z KTBW SOUNDING PROFILE SAMPLED
THESE WINDS ALOFT WELL...SHOWING A DEEP LAYER WEST FLOW ABOVE
700MB.
AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO
THE WEST OVER THE FLORIDA PENINSULA AND EASTERN GULF OF MEXICO. A
COMPLEX FRONTAL SYSTEM REMAINS WELL TO OUR NORTH AND NORTHWEST
FROM SOUTHERN TEXAS TO THE LOWER MS VALLEY AND NORTHEAST INTO THE
OHIO VALLEY. CLUSTERS OF SHOWERS AND STORMS ARE FORMING AND
ONGOING IN ADVANCE OF THIS FRONT...BUT WILL ALSO REMAIN WELL
REMOVED FROM OUR FORECAST AREA. THE ONLY IMPACT FROM THESE STORMS
THAT WE MAY SEE IS AN INCREASE IN HIGH CLOUDS LATER TODAY ACROSS
THE NORTHERN NATURE COAST ZONES ASSOCIATED WITH ANVIL BLOWOFF
ADVECTING DOWNSTREAM IN THE SYNOPTIC UPPER FLOW.
&&
.SHORT TERM (REST OF TODAY THROUGH MONDAY)...
BENIGN WEATHER WILL CONTINUE FOR THE NEXT SEVERAL HOURS AS
TEMPERATURES CONTINUE TO CLIMB THROUGH THE 80S...TOWARD AFTERNOON
HIGH TEMPS IN THE VICINITY OF 90 AWAY FROM THE BEACHES. THE STRONG
TERRESTRIAL HEATING WILL EVENTUALLY VEER WINDS NEAR THE COAST
ONSHORE...MAINLY AFTER 18Z. WITH THE SYNOPTIC FLOW FROM THE
SOUTHEAST...THE FLORIDA EAST COAST SEA-BREEZE WILL RACE ACROSS THE
STATE AND SET UP THE MAIN CONVERGENCE ZONE WITH THE WEST COAST
SEA-BREEZE SOMEWHERE NEAR OR JUST EAST OF THE I-75 CORRIDOR DURING
THE LATE AFTERNOON/EARLY EVENING HOURS.
LIKELY THE MOST IMPORTANT FEATURE FOR OUR FORECAST SAMPLED IN THE
KTBW SOUNDING COLUMN THIS MORNING...IS THE DEFINED
SUBSIDENCE/CAPPING INVERSION SEEN BETWEEN 700-625MB. THIS IS A
SIGNIFICANT OBSTACLE FOR PARCELS TO OVERCOME TODAY IN THE PROCESS
OF CONVECTION. ALLOWING FOR DAYTIME MIXING TO OCCUR UP TO A
SURFACE TEMP AROUND 90 STILL HAS TROUBLE OVERCOMING THIS CAP.
CERTAINLY SEEMS LIKE MANY OF THE 06Z GUIDANCE MEMBERS
UNDERESTIMATED THE STRENGTH OF THIS CAP...AND HAVE NOTICED THE
LATEST HRRR BUFR SOUNDINGS ARE HAVING A MORE DIFFICULT TIME
BREAKING THE CAP INTO FREE CONVECTION COMPARED TO EARLIER RUNS
THAT WERE NOT UTILIZING THIS REAL-TIME SOUNDING DATA.
THIS CAP WILL CERTAINLY DELAY THE ONSET OF ANY CONVECTION AS WE
WILL NEED TO REACH ABSOLUTE PEAK HEATING IF PARCELS ARE GOING TO
HAVE ANY CHANCE OF GETTING BY THIS INVERSION. LIKELY WE WILL
REQUIRE THE HIGHER DEWPOINTS WITHIN THE CONVERGENCE ZONE
ASSOCIATED WITH BOUNDARY MOISTURE POOLING TO REACH THE CAPE NEEDED
FOR STORMS. THEREFORE...STORMS SHOULD HAVE A LATE START...BE
ISOLATED TO WIDELY SCATTERED IN NATURE...AND OCCUR IN A FAIRLY
NARROW ZONE ALONG AND JUST EAST OF I-75.
TONIGHT...
WITH THE LATE START TO ANY CONVECTION...WOULD ANTICIPATE THE
CELLS THAT DO DEVELOP TO LINGERING FOR A FEW HOURS PAST SUNSET.
WILL KEEP A LOW CHANCE POP IN THE FORECAST FOR THIS FAVORED
CONVERGENCE ZONE UNTIL 03Z...AND THEN ALLOW THE REST OF THE
OVERNIGHT TO BE DRY REGION-WIDE. A FEW POCKETS OF FOG ARE QUITE
LIKELY IN THE HOURS BEFORE DAWN...BUT NEITHER THE SREF OR
STATISTICAL GUIDANCE ARE SUGGESTING WE WILL HAVE ANY SIGNIFICANT
VIS ISSUES FOR THE MORNING COMMUTE. GIVEN THAT THE COVERAGE OF
RAINFALL TODAY SHOULD BE LOW...WOULD AGREE WITH THE NWP. LOW
TEMPERATURES TONIGHT WILL BE SEASONABLY WARM WITH UPPER 60S INLAND
AND LOWER 70S ALONG THE COAST.
MONDAY...
OVERALL THE SYNOPTIC PATTERN IS NOT ALL THAT DIFFERENT FROM
TODAY. THE MOST INFLUENTIAL DIFFERENCE MAY BE THAT THE MID/UPPER
LEVEL ENVIRONMENT IS SLIGHTLY MORE MOIST AND HENCE A BIT LESS
HOSTILE TOWARD DEEP CONVECTION. ALSO...THERE DOES STILL SEEM TO BE
A HINT OF THE CAPPING INVERSION IN THE FORECAST SOUNDINGS...BUT AT
LEAST FOR NOW...IT APPEARS LESS DRAMATIC. BOTH OF THESE FACTORS
SHOULD CONTRIBUTE TO A BIT HIGHER COVERAGE OF LATE DAY STORMS
ACROSS THE SAME FAVORED CONVERGENCE ZONE RUNNING ALONG AND JUST
EAST OF THE I-75 CORRIDOR. INHERITED FORECAST HAS 30-40% POPS IN
THIS ZONE...AND THEN TAPERS RAIN CHANCES BACK TO 10-20% AT THE
COAST. BASED ON THE EARLIER MEMBERS OF THE 12Z GUIDANCE CYCLE TO
ARRIVE...DO NOT SEE MUCH REASON TO MAKE SIGNIFICANT CHANGES. WILL
WAIT FOR ALL THE 12Z CONVECTION ALLOWING GUIDANCE TO ARRIVE BEFORE
MAKING A FINAL FORECAST DECISION ON TOMORROW. ANY CONVECTION ON
MONDAY WILL AGAIN BE SUPPRESSED BY THE ENVIRONMENT ALOFT UNTIL
LATE IN THE AFTERNOON OR EARLY EVENING...WHICH SHOULD AGAIN ALLOW
LOCATIONS AWAY FROM THE IMMEDIATE COAST TO PUSH 90 FOR HIGH
TEMPERATURES. AT THE BEACHES TEMPS HOLD IN THE 80S WITH THE
DEVELOPMENT ONSHORE FLOW DURING THE AFTERNOON.
ENJOY THE REMAINDER OF YOUR SUNDAY EVERYONE!
&&
.AVIATION...
01/12Z CYCLE. PREVAILING VFR WITH FEW TO SCT CU AND CI CLOUDS.
LIGHT SE TO EAST WINDS CURRENTLY...SHIFTING TO ONSHORE ALONG THE
COAST DURING THE NEXT FEW HOURS. ISOLATED SHOWERS/STORMS ALONG
THE SEA-BREEZE LATE AFTERNOON/EARLY EVENING. BEST POTENTIAL FOR A
SHOWER AFTER 19Z FOR KPGD/KFMY/KRSW...HOWEVER RAIN CHANCES EVEN
FOR THESE TERMINALS LOW ENOUGH TO EXCLUDE MENTION IN CURRENT TAF.
&&
.MARINE...
ATLANTIC HIGH PRESSURE WILL RIDGE ACROSS FLORIDA INTO
THE EASTERN GULF OF MEXICO THROUGH EARLY NEXT WEEK. THIS RIDGE
WILL SLIDE TO THE EAST AS A COLD FRONT ENTERS THE GULF AND MOVES
ACROSS THE FORECAST WATERS WEDNESDAY. WINDS SHIFT NORTH BEHIND
THIS FRONT AND MAY APPROACH ADVISORY LEVELS FOR A TIME WEDNESDAY
NIGHT INTO THURSDAY. HIGH PRESSURE THEN BUILDS OVER THE REGION BY
THE BEGINNING OF NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 73 88 74 / 10 10 20 10
FMY 89 71 89 72 / 20 20 40 20
GIF 91 71 91 71 / 20 20 30 30
SRQ 84 72 85 72 / 0 10 10 10
BKV 90 68 88 67 / 10 10 20 20
SPG 87 74 86 74 / 0 10 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE...14/MROCZKA
Area Forecast Discussion
National Weather Service Lincoln IL
1102 AM CDT SUN MAY 1 2016
.UPDATE...
Issued at 1102 AM CDT Sun May 1 2016
Made some updates to the forecast earlier this morning to drop
PoPs across the board during the morning and to go with mostly
sunny skies south of I-70. Latest visible satellite imagery
continues to show overcast conditions across much of the KILX CWA,
with areas south of I-70 still seeing plenty of sunshine. As a
result, a strong temperature gradient has developed across the
area...with readings ranging from the upper 40s far north around
Lacon to close to 70 degrees far southeast. HRRR suggests the
clouds will gradually thin this afternoon, but think this might be
too optimistic based on prevailing northeast flow north of frontal
boundary in the Ohio River Valley. As a result, will continue with
a mostly cloudy forecast across much of the area. As an upper low
currently over southern Iowa shears northeastward, scattered
showers and a few thunderstorms will develop during the afternoon.
Think the best areal coverage of precip will remain focused
across the central and northern CWA, where high chance PoPs are
warranted. PoPs will decrease further southeast away from the
stronger forcing. Severe threat will remain minimal today, as
best forcing and strongest instability will not coincide anywhere
across the CWA. Afternoon high temperatures will range from the
lower 50s north of Peoria, to the lower to middle 70s south of
I-70.
&&
.SHORT TERM...(Today)
ISSUED AT 305 AM CDT Sun May 1 2016
A rather complex forecast exists across central and southeast
Illinois today, with many factors to consider. A nearly stationary
surface front cuts across the forecast area generally a little south
of, and nearly parallel to, the I-72 corridor. To the south of the
boundary, partly cloudy skies exist, with scattered convection to
the south of I-70. To the north of the boundary, extensive
fog/stratus exists, with visibilities significantly reduced in some
areas. The fog is most dense near the edge of the stratus, and
surface obs suggest a Dense Fog Advisory should be considered.
However, the cloud edge is slowly sinking to the south and this
would suggest that dense fog will not remain in any one location for
a significant period of time. Plan to hold off on Dense Fog Advisory
for now with this in mind, but will continue to monitor visibility
trends closely through sunrise.
Other main concern is the expected precipitation coverage today. A
broad northeast to southwest oriented upper-level trof stretches
across the lower 48 states, with several smaller scale upper lows
embedded within it. The feature we need to key in on today is the
upper low spinning over the central Plains. This feature is expected
to shear northeast into the Great Lakes region today. The forcing
associated with this weakening feature, and associated wave on the
surface front, will be our primary precipitation trigger. There is
currently very little on radar upstream, and expect the bulk of our
precipitation will occur through a combination of diurnal heating
and mid-level cooling with the approach of the upper low remnants.
This thinking supports scattered showers across the area by
afternoon, with a few thunderstorms also possible. The thunderstorms
should mostly occur along/south of the surface front. A few of the
storms along/south of I-70 may be strong given the modest
instability (CAPEs from 1000-2000 j/kg) and shear profiles (bulk
shear to 45 kts) anticipated by afternoon.
A significant N-S temperatures gradient is likely across the area
today with the surface front in the area. Daytime highs should range
from the mid 50s NW around Galesburg to mid 70s SE around
Lawrenceville.
.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT Sun May 1 2016
Persistent upper troughing pattern expected over the eastern U.S.
much of the upcoming week, as a significant ridge builds west of the
Rockies. This will send lobes of cooler air southward into the Great
Lakes region, with 850 mb temperatures over our area dipping to
around zero Celsius on Tuesday, and Wednesday night through
Thursday. This should result in highs several degrees below normal
for early May. Late in the week, an omega blocking pattern will
evolve, although the latest runs of the ECMWF and GFS do show the
ridge edging eastward, bringing a significant warming trend for next
weekend.
Remnants of current upper low over Nebraska will drift eastward
early this week, and stretch out into a trough which will drop
toward the Ohio Valley on Tuesday. With these features around, it
will be difficult to eliminate mention of PoP`s. Have increased rain
chances to around 30% on Monday over the southeast CWA and went with
slight chances as far north as Bloomington and Havana, with the
threat diminishing with loss of daytime heating. With the trough
further south on Tuesday, slight chance PoP`s were kept over the
areas south of I-70. A more significant rain chance is expected late
Tuesday night into Wednesday, as a large upper low drops southward
into the Great Lakes. Have increased PoP`s to around 35-40% over the
eastern CWA on Wednesday. Rather significant cold pocket at 500 mb
will accompany this low, and would not be surprised to see some
isolated thunder. However, the coldest part of this will be tracking
into Indiana, so will hold off on any thunder mention for now. Dry
weather is expected late in the week, as high pressure dominates the
Mississippi Valley as the upper ridge arrives.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 654 AM CDT Sun May 1 2016
IFR or lower aviation weather conditions expected through the
bulk of the 12Z TAF valid time. Some improvement to MVFR is
possible at KSPI, KDEC, and KCMI this afternoon through diurnal
mixing, but IFR conditions should quickly return tonight. While
the coverage is not expected to be great, scattered showers/storms
are likely this afternoon as an upper level disturbance passes
through the area and diurnal heating is maximized.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...BAK
LONG TERM...Geelhart
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
819 AM CDT SUN MAY 1 2016
.SYNOPSIS...
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM CONTINUES TO SLOWLY PUSH ACROSS SOUTHEASTERN
NEBRASKA THIS MORNING. DEFORMATION BAND STRETCHES ACROSS NORTH
CENTRAL INTO SOUTHWEST NEBRASKA. PRECIP TYPE GENERALLY RAIN EAST
OF HIGHWAY 83 THEN A MIX OR A CHANGE TO ALL SNOW TO THE WEST OF
83. TEMPS HAVE HELD FAIRLY STEADY MOST OF THE NIGHT IN THE MID
30S TO AROUND 40...HOWEVER THE LAST HOUR HAS SEEN A RISE OF A
DEGREE IN A FEW SPOTS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM WILL FINALLY PUSH FAR ENOUGH TO THE EAST THAT
AN END TO THE RAIN/SNOW IS EXPECTED TODAY. THE BAND HAS BECOME
MORE BROKEN OVERNIGHT...WITH THIS TREND EXPECTED TO CONTINUE
THROUGH THE MORNING HOURS. MOST MODELS HAVE THE CWA DRY FOR THE
AFTN...HOWEVER THE LATEST HRRR KEEPS THE EASTERN ZONES IN LIGHT
SHOWERS INTO THE AFTERNOON HOURS. CURRENT THINKING IS THE DRY AIR
FROM THE NORTH WILL GET DRAWN INTO THE AREA...ALONG WITH RISING
TEMPS DUE TO DAYTIME HEATING AND WARM AIR ADVECTION FROM
DEPARTING LOW...WITH THE FORECAST PRIMARILY DRY. WITH TEMPS
ALREADY STARTING TO RISE...EXPECT THE THREAT FOR SNOW TO QUICKLY
END WITH LIQUID PRECIP TO BE THE PREDOMINATE P-TYPE. WILL HAVE TO
MONITOR FOR THE AFTERNOON AS SOME ISOLATED SPRINKLES/LIGHT RAIN
SHOWERS CAN NOT BE RULED OUT.
CLOUDS LINGERING THROUGH THE DAY AND WILL LIMIT HEATING. HAVE
GONE WITH THE COOLER GUIDANCE AS MOST GUIDANCE HAS BEEN TOO WARM
THE PAST FEW DAYS. BY TONIGHT DECREASING CLOUDS COMBINE WITH
LIGHT WINDS FOR A GOOD SET UP FOR RADIATIONAL COOLING. TEMPS
LIKELY TO DIP BELOW FREEZING FOR MOST WESTERN LOCATIONS. STILL A
LITTLE EARLY FOR ANY FROST HEADLINES...AND MANY LOCATIONS WITH
THE COOLER TEMPS EXPECTED...JUST SAW ACCUMULATING SNOWS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN MAY 1 2016
MID RANGE...MONDAY AND TUESDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION. IN THE WAKE OF THE CLOSED LOW THAT
BROUGHT PERSISTENT RAIN AND SNOW TO THE AREA... A SHORTWAVE WILL
TRAVERSE THE SANDHILLS LATE MONDAY.
MONDAY... MADE LITTLE CHANGE TO MAX TEMPS EXCEPT FOR COOLED THE
SOUTHWEST CORNER NEAR COLORADO TO ACCOUNT FOR POSSIBLE REMAINING
SNOW PACK. CURRENT FORECAST HIGHS ARE SLIGHTLY BELOW MOS GUIDANCE...
BUT INCREASING CLOUD COVER WITH THE SHORTWAVE MAY HELP OFFSET WAA.
WITH BETTER AGREEMENT AMONG THE MODELS REGARDING THE WAVE AND MID
LEVEL FRONTOGENESIS... INTRODUCED SCHC POPS BEGINNING 18Z. NAM KEEPS
THE AREA DRY DUE TO OVERALL LACK OF MOISTURE AND LIFT. GFS AND EURO
ARE MORE BULLISH WITH THE MOISTURE AND DEPICT AN AREA OF 500-700HPA
SATURATION OVER THE CWA LATE MONDAY. LIFT IS STILL RATHER WEAK IN
GFS SOUNDINGS... BUT MOISTURE AND FGEN MAY BE STRONG ENOUGH IN THE
MID LEVELS TO OVERCOME RELATIVELY DRY AIR NEAR THE SURFACE.
TUESDAY... SHUT OFF POPS BY 12Z ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA AS THE WAVE IS FAIRLY QUICK PASSING. SWITCHED PTYPE TO
RASN WEST OF NEB HWY 61 WHERE HIGHER ELEVATION AND COOLER LOW TEMPS
WOULD SUPPORT A MIX. AS THIS LOOKS LIKE A LIGHT PRECIP EVENT AT
MOST... SHOULD NOT BE ADEQUATE DYNAMIC COOLING TO RESULT IN ALL SNOW
AND THUS KEPT SNOW AMOUNTS AT ZERO. DID PUSH MAX TEMPS UP A
DEGREE... WHICH LEANS TOWARD MAV AND MET. SKY SHOULD CLEAR OUT
QUICKLY BEHIND THE SHORTWAVE... AND MODELS ARE CONSISTENT WITH
NOTICEABLE WAA ACROSS THE REGION. GFS AND NAM BRING H85 TEMPS TO 11C
NORTH CENTRAL AND 14C FAR WEST. PLENTY OF DRY AIR ALOFT WILL ALLOW
FOR UNINHIBITED MIXING TO NEAR 700HPA... AND WITH A SLIGHT DOWNSLOPE
COMPONENT AT 850HPA... HIGHS SHOULD BE ABLE TO REACH NEAR 70F.
LONG RANGE...WEDNESDAY THROUGH SATURDAY... THIS PERIOD IS DOMINATED
BY A BLOCKING PATTERN ALOFT... RESULTING IN AN AMPLIFIED RIDGE OVER
THE GREAT PLAINS. WEAK WAA AND DRY WEATHER CONTINUE THROUGHOUT THE
WEEK WITH HIGHS IN THE LOWER/MID 70S. MOISTURE ADVECTION REALLY
TAKES SHAPE LATE WEEK AS LOW LEVEL FLOW TURNS SOUTHERLY. GFS AND
EURO ARE PUSHING SFC DEW POINTS INTO THE LOWER 50S ALONG/EAST OF HWY
83 THURSDAY PM AND MID/UPPER 50S FRIDAY PM. BOTH MODELS HAVE A LOW
LEVEL JET DEVELOPING FRIDAY NIGHT. THE BRUNT OF THE SPEED
CONVERGENCE IS OVER THE SANDHILLS... SO FELT CONFIDENT ENOUGH TO
RETAIN CHC POPS OVERNIGHT. THE WESTERN CLOSED LOW REACHES THE
SOUTHWEST DESERT SATURDAY... WHICH BEGINS THE RIDGE BREAKDOWN PHASE
FOR WESTERN NEBRASKA. THE H3 JET FEATURES A 100+KT STREAK POINTED
TOWARD EASTERN COLORADO SATURDAY PM... AND WITH DEW POINTS NOW
PUSHING 60F... THUNDERSTORMS ARE A DISTINCT POSSIBILITY. GFS AND
EURO ARE IN SURPRISINGLY GOOD AGREEMENT WITH THE SFC LOW NEAR KSNY
AND H5 LOW OVER KLAS 00Z SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 657 AM CDT SUN MAY 1 2016
BAND OF SHOWERS WILL CONTINUE TO ROTATE ACROSS NORTH CENTRAL INTO
SOUTHWEST NEBRASKA THIS MORNING. THE LOW RESPONSIBLE FOR THE RAIN
WILL CONTINUE TO DRIFT TO THE EAST...WITH THE SHOWERS COMING TO
AN END BY THIS AFTERNOON. SKIES ARE ALREADY BECOMING WIDESPREAD
VFR ACROSS NORTHERN NEBRASKA...INCLUDING KVTN...AND THIS WILL
SPREAD SOUTH THROUGH THE DAY. BY LATE THIS AFTERNOON DRY AND VFR
CONDITIONS ACROSS THE ENTIRE AREA...WHICH WILL CONTINUE TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 819 AM CDT SUN MAY 1 2016
AN AREAL FLOOD WARNING HAS BEEN ISSSUED ALONG THE UPPER REACHES OF
THE ELKHORN RIVER. THE RIVER GAGE AT ATKINSON HAS JUST REACHED
FLOOOD STAGE AND IS LIKELY TO REMAIN SLIGHTLY ABOVE FLOOD STAGE
FOR AT LEAS THE NEXT FEW DAYS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MASEK
SHORT TERM...MASEK
LONG TERM...SNIVELY
AVIATION...MASEK
HYDROLOGY...ROBERG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
658 AM CDT SUN MAY 1 2016
.SYNOPSIS...
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM CONTINUES TO SLOWLY PUSH ACROSS SOUTHEASTERN
NEBRASKA THIS MORNING. DEFORMATION BAND STRETCHES ACROSS NORTH
CENTRAL INTO SOUTHWEST NEBRASKA. PRECIP TYPE GENERALLY RAIN EAST
OF HIGHWAY 83 THEN A MIX OR A CHANGE TO ALL SNOW TO THE WEST OF
83. TEMPS HAVE HELD FAIRLY STEADY MOST OF THE NIGHT IN THE MID
30S TO AROUND 40...HOWEVER THE LAST HOUR HAS SEEN A RISE OF A
DEGREE IN A FEW SPOTS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM WILL FINALLY PUSH FAR ENOUGH TO THE EAST THAT
AN END TO THE RAIN/SNOW IS EXPECTED TODAY. THE BAND HAS BECOME
MORE BROKEN OVERNIGHT...WITH THIS TREND EXPECTED TO CONTINUE
THROUGH THE MORNING HOURS. MOST MODELS HAVE THE CWA DRY FOR THE
AFTN...HOWEVER THE LATEST HRRR KEEPS THE EASTERN ZONES IN LIGHT
SHOWERS INTO THE AFTERNOON HOURS. CURRENT THINKING IS THE DRY AIR
FROM THE NORTH WILL GET DRAWN INTO THE AREA...ALONG WITH RISING
TEMPS DUE TO DAYTIME HEATING AND WARM AIR ADVECTION FROM
DEPARTING LOW...WITH THE FORECAST PRIMARILY DRY. WITH TEMPS
ALREADY STARTING TO RISE...EXPECT THE THREAT FOR SNOW TO QUICKLY
END WITH LIQUID PRECIP TO BE THE PREDOMINATE P-TYPE. WILL HAVE TO
MONITOR FOR THE AFTERNOON AS SOME ISOLATED SPRINKLES/LIGHT RAIN
SHOWERS CAN NOT BE RULED OUT.
CLOUDS LINGERING THROUGH THE DAY AND WILL LIMIT HEATING. HAVE
GONE WITH THE COOLER GUIDANCE AS MOST GUIDANCE HAS BEEN TOO WARM
THE PAST FEW DAYS. BY TONIGHT DECREASING CLOUDS COMBINE WITH
LIGHT WINDS FOR A GOOD SET UP FOR RADIATIONAL COOLING. TEMPS
LIKELY TO DIP BELOW FREEZING FOR MOST WESTERN LOCATIONS. STILL A
LITTLE EARLY FOR ANY FROST HEADLINES...AND MANY LOCATIONS WITH
THE COOLER TEMPS EXPECTED...JUST SAW ACCUMULATING SNOWS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN MAY 1 2016
MID RANGE...MONDAY AND TUESDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION. IN THE WAKE OF THE CLOSED LOW THAT
BROUGHT PERSISTENT RAIN AND SNOW TO THE AREA... A SHORTWAVE WILL
TRAVERSE THE SANDHILLS LATE MONDAY.
MONDAY... MADE LITTLE CHANGE TO MAX TEMPS EXCEPT FOR COOLED THE
SOUTHWEST CORNER NEAR COLORADO TO ACCOUNT FOR POSSIBLE REMAINING
SNOW PACK. CURRENT FORECAST HIGHS ARE SLIGHTLY BELOW MOS GUIDANCE...
BUT INCREASING CLOUD COVER WITH THE SHORTWAVE MAY HELP OFFSET WAA.
WITH BETTER AGREEMENT AMONG THE MODELS REGARDING THE WAVE AND MID
LEVEL FRONTOGENESIS... INTRODUCED SCHC POPS BEGINNING 18Z. NAM KEEPS
THE AREA DRY DUE TO OVERALL LACK OF MOISTURE AND LIFT. GFS AND EURO
ARE MORE BULLISH WITH THE MOISTURE AND DEPICT AN AREA OF 500-700HPA
SATURATION OVER THE CWA LATE MONDAY. LIFT IS STILL RATHER WEAK IN
GFS SOUNDINGS... BUT MOISTURE AND FGEN MAY BE STRONG ENOUGH IN THE
MID LEVELS TO OVERCOME RELATIVELY DRY AIR NEAR THE SURFACE.
TUESDAY... SHUT OFF POPS BY 12Z ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA AS THE WAVE IS FAIRLY QUICK PASSING. SWITCHED PTYPE TO
RASN WEST OF NEB HWY 61 WHERE HIGHER ELEVATION AND COOLER LOW TEMPS
WOULD SUPPORT A MIX. AS THIS LOOKS LIKE A LIGHT PRECIP EVENT AT
MOST... SHOULD NOT BE ADEQUATE DYNAMIC COOLING TO RESULT IN ALL SNOW
AND THUS KEPT SNOW AMOUNTS AT ZERO. DID PUSH MAX TEMPS UP A
DEGREE... WHICH LEANS TOWARD MAV AND MET. SKY SHOULD CLEAR OUT
QUICKLY BEHIND THE SHORTWAVE... AND MODELS ARE CONSISTENT WITH
NOTICEABLE WAA ACROSS THE REGION. GFS AND NAM BRING H85 TEMPS TO 11C
NORTH CENTRAL AND 14C FAR WEST. PLENTY OF DRY AIR ALOFT WILL ALLOW
FOR UNINHIBITED MIXING TO NEAR 700HPA... AND WITH A SLIGHT DOWNSLOPE
COMPONENT AT 850HPA... HIGHS SHOULD BE ABLE TO REACH NEAR 70F.
LONG RANGE...WEDNESDAY THROUGH SATURDAY... THIS PERIOD IS DOMINATED
BY A BLOCKING PATTERN ALOFT... RESULTING IN AN AMPLIFIED RIDGE OVER
THE GREAT PLAINS. WEAK WAA AND DRY WEATHER CONTINUE THROUGHOUT THE
WEEK WITH HIGHS IN THE LOWER/MID 70S. MOISTURE ADVECTION REALLY
TAKES SHAPE LATE WEEK AS LOW LEVEL FLOW TURNS SOUTHERLY. GFS AND
EURO ARE PUSHING SFC DEW POINTS INTO THE LOWER 50S ALONG/EAST OF HWY
83 THURSDAY PM AND MID/UPPER 50S FRIDAY PM. BOTH MODELS HAVE A LOW
LEVEL JET DEVELOPING FRIDAY NIGHT. THE BRUNT OF THE SPEED
CONVERGENCE IS OVER THE SANDHILLS... SO FELT CONFIDENT ENOUGH TO
RETAIN CHC POPS OVERNIGHT. THE WESTERN CLOSED LOW REACHES THE
SOUTHWEST DESERT SATURDAY... WHICH BEGINS THE RIDGE BREAKDOWN PHASE
FOR WESTERN NEBRASKA. THE H3 JET FEATURES A 100+KT STREAK POINTED
TOWARD EASTERN COLORADO SATURDAY PM... AND WITH DEW POINTS NOW
PUSHING 60F... THUNDERSTORMS ARE A DISTINCT POSSIBILITY. GFS AND
EURO ARE IN SURPRISINGLY GOOD AGREEMENT WITH THE SFC LOW NEAR KSNY
AND H5 LOW OVER KLAS 00Z SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 657 AM CDT SUN MAY 1 2016
BAND OF SHOWERS WILL CONTINUE TO ROTATE ACROSS NORTH CENTRAL INTO
SOUTHWEST NEBRASKA THIS MORNING. THE LOW RESPONSIBLE FOR THE RAIN
WILL CONTINUE TO DRIFT TO THE EAST...WITH THE SHOWERS COMING TO
AN END BY THIS AFTERNOON. SKIES ARE ALREADY BECOMING WIDESPREAD
VFR ACROSS NORTHERN NEBRASKA...INCLUDING KVTN...AND THIS WILL
SPREAD SOUTH THROUGH THE DAY. BY LATE THIS AFTERNOON DRY AND VFR
CONDITIONS ACROSS THE ENTIRE AREA...WHICH WILL CONTINUE TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT SUN MAY 1 2016
THE HEAVIEST PRECIPITATION HAS ENDED ACROSS THE CWA WITH ONLY LIGHT
QPF AMOUNTS EXPECTED THIS MORNING. WHILE SO FAR RIVERS HAVE REMAINED
INSIDE THERE BANKS...MANY ARE ON THE RISE. SEVERAL AREA RIVER
FORECAST HAVE INCREASED TO ACTION STAGE...HOWEVER NONE ARE
FORECASTED TO REACH FLOOD STAGE AT THIS TIME. THE SLOW DURATION OF
THE RAINFALL HAS ALLOW MOST OF THE PRECIP TO SOAK INTO THE GROUND.
THIS SATURATED GROUND FROM THE PAST COUPLE OF STORM SYSTEMS HAS
RESULTED IN NUMEROUS FIELDS AND PASTURES TO HAVE POCKETS OF STANDING
WATER. WHILE NO FLOODING IS EXPECTED AT THIS TIME...RIVER RESPONSES
WILL CONTINUED TO BE MONITORED CLOSELY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MASEK
SHORT TERM...MASEK
LONG TERM...SNIVELY
AVIATION...MASEK
HYDROLOGY...MASEK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
923 AM EDT SUN MAY 1 2016
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL TRACK EAST ALONG A FRONTAL BOUNDARY
AND INTO OHIO TODAY. THIS WILL ACT AS A FOCUS FOR SHOWERS AND
THUNDERSTORMS TO DEVELOP. THE FRONT WILL WORK INTO SOUTHERN
KENTUCKY AND WEST VIRGINIA TONIGHT...BUT ANOTHER WAVE WILL KEEP
THE CHANCE OF PRECIPITATION IN THE FORECAST FOR MONDAY INTO MONDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MORNING CONVECTION ALONG THE OHIO RIVER HAS JUST ABOUT CLEARED
OUT OF THE ILN FORECAST AREA...WITH LIGHTER RADAR ECHOES WITHIN AN
AREA OF THICK LOW-LEVEL CLOUDS ALSO SHOWING SIGNS OF DISSIPATION.
SATELLITE IMAGERY SUGGESTS THAT PARTIAL CLEARING HAS BEGUN TO WORK
INTO SECTIONS OF THE FORECAST AREA...BUT WITH PATCHES OF STRATUS
AND MID-LEVEL CLOUDS THAT APPEAR UNLIKELY TO COMPLETELY DEPART THE
AREA.
THESE CLOUDS WILL PLAY A PART IN DETERMINING HOW MUCH INSTABILITY
IS ABLE TO BE GENERATED TODAY...AN IMPORTANT KEY TO THE FORECAST
FOR CONVECTION...ESPECIALLY WITH MODEL TIMING AND INTENSITY
EXPECTATIONS STILL FAR FROM A NICE CONSENSUS. BASED ON THE 12Z
KILN SOUNDING AND SREF PROBABILITIES...IF TEMPERATURES IN THE
SOUTHERN HALF OF THE FORECAST AREA ARE ABLE TO GET INTO THE LOWER
70S AS CURRENTLY FORECAST...SBCAPE OF 1200-1800 J/KG WILL BE
ATTAINABLE.
IN TERMS OF TIMING AND PLACEMENT...THIS REMAINS SOMEWHAT IN
QUESTION...BUT RECENT HRRR RUNS HAVE PERHAPS SHOWN THE MOST
PROMISE IN ALIGNING BEST WITH THE OBSERVED SURFACE PATTERN.
ALONG A WEAK AND NEARLY-STATIONARY SURFACE BOUNDARY...SCATTERED
SHOWERS AND STORMS ARE EXPECTED TO DEVELOP IN THE SOUTHERN HALF OF
THE FORECAST AREA BETWEEN 18Z-20Z...MOVING EAST AND OUT OF THE
CWA BY 00Z. ADDITIONAL STORMS MAY DEVELOP FURTHER TO THE NORTHWEST
DURING THE EVENING...AHEAD OF AN INCOMING SHORTWAVE. LOW-LEVEL
FORCING IS NOT IMPRESSIVE...AND SUBSEQUENTLY THE LOW-LEVEL WIND
FLOW IS ALSO FAIRLY WEAK. DEEP-LAYER WEST-SOUTHWESTERLY SHEAR IS
MORE NOTABLE (45-50 KNOTS)...WHICH WILL LIKELY COMBINE WITH THE
INSTABILITY TO PRODUCE A FEW STRONG (TO POSSIBLY SEVERE) STORMS.
SINCE DESTABILIZATION IS ONE OF THE BIGGER QUESTIONS FOR THE
DAY...A ADDITIONAL KILN SOUNDING WILL BE CONDUCTED AT 17Z...IN
ORDER TO ASSESS THE EARLY AFTERNOON ATMOSPHERIC CONDITIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
CONVECTION SHOULD STILL BE ON GOING FROM THE AFTERNOON INTO THE
EARLY EVENING HOURS AS THE FILLING H5 TROF LIFTS OUT OVER THE
GREAT LAKES. HIGHEST POPS WILL BE AT THE BEGINNING OF THE TONIGHT
PERIOD...WITH THE PCPN CHANCES SLOWLY DECREASING FROM SW TO NE
AFTER THE MIDNIGHT HOUR.
A FEW SHOWERS COULD BE LINGERING IN CENTRAL OHIO EARLY MONDAY
MORNING...BEFORE PUSHING OFF TO THE EAST. PCPN WILL REDEVELOP
MONDAY ALONG THE FRONTAL BOUNDARY WHICH HAD DROPPED INTO SRN KY
DURING SUNDAY NIGHT. ANOTHER WAVE ON THE FRONT WILL PUSH PCPN
INTO THE REGION MONDAY AFTERNOON. HIGHS ON MONDAY WILL BE MUCH
COOLER THAN SUNDAY...WITH HIGHS ONLY MAKING IT IN THE UPPER 50S IN
THE NORTH. THE SOUTHEAST COUNTIES SHOULD MAKE IT INTO THE UPPER
60S HOWEVER.
H5 ENERGY DIGGING DOWN FROM CANADA INTO THE OHIO AND TENNESSEE
VALLEYS WILL KEEP A LINGERING CHANCE OF SHOWERS ACROSS THE
SOUTHERN COUNTIES ON TUESDAY. HIGHS WILL BE IN THE MID 60S ACROSS
THE ENTIRE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
NUMERICAL MODEL SOLNS GENERALLY SIMILAR WITH NRN STREAM TROF
SHARPENING UP AND DIGGING SOUTH AT MID WEEK. THIS WILL ALLOW A SFC
COLD FRONT TO DROP SOUTH THRU ILN/S FA WEDNESDAY. INSTABILITY IS
MARGINAL AT BEST...SO AT THIS TIME HAVE ELECTED TO KEEP PCPN
MENTION TO CHANCE OF SHOWERS. TEMPERATURES WILL CONTINUE TO REMAIN
CLOSE TO NORMAL WITH HIGHS WED FROM THE MID 60S NORTH TO AROUND 70
SOUTH.
DIGGING TROF DEVELOPS INTO DEEP LARGE CLOSED LOW WHICH WILL CONTINUE
TO INFLUENCE OUR WEATHER THRU AT LEAST THE END OF THE WEEK. THIS
FEATURE WILL KEEP CHANCE POPS FOR SHOWERS IN THE FCST THURSDAY AND
FRIDAY. MAY HAVE TO INCLUDE A MENTION OF SHOWERS IN THE EAST ON
SATURDAY WITH THE SOME EVIDENCE THAT MOISTURE WILL CONTINUE TO WRAP
AROUND THIS LARGE LOW. FOR NOW HAVE OPTED FOR DRY SOLN SATURDAY.
TEMP WISE...UNDER THE INFLUENCE OF THIS LOW...BOTH THURSDAY AND
FRIDAY WILL BE BELOW NORMAL WITH HIGHS FROM THE UPPER 50S NORTH TO
THE MID 60S SOUTH. READINGS WILL ONLY MODERATE A LTL SATURDAY WITH
HIGHS FROM THE LOWER 60S NORTH THE UPPER 60S SOUTH.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
IFR CIGS HAVE STARTED TO BREAK THIS MORNING TO MVFR/ VFR AS RAIN
HAS COME TO A TEMPORARY BREAK ACROSS THE AREA. THIS TEMPORARY
BREAK IS THANKS TO AN UPPER LEVEL DISTURBANCE EXITING THE AREA
ALLOWING FOR SOME WEAK SUBSIDENCE OVER THE AREA. ANOTHER UPPER
LEVEL DISTURBANCE WILL APPROACH FROM THE SOUTHWEST THIS AFTERNOON
ALLOWING FOR THE CHANCE OF PRECIP TO COME RIGHT BACK. NAM FORECAST
SOUNDINGS ARE VERY AGGRESSIVE WITH INSTABILITY WHILE THE GFS AND
RAP ARE MORE RESERVED. HIGH RES MODELS ARE ALSO SCATTERED WITH
PRECIP AND HAVE NOT DONE A GOOD JOB THIS MORNING. GIVEN THESE
REASONS HAVE LEFT THE MENTION OF THUNDER OUT OF THE TAFS FOR NOW.
AM EXPECTING MOSTLY VFR CIGS THIS AFTERNOON BUT REDUCED CIGS AND
VISIBILITIES ARE POSSIBLE IN ANY HEAVIER CELLS THAT FORM OVER THE
TERMINALS.
GLOBAL AND HIGH RES MODELS AGAIN ARE STRUGGLING WITH THE TIMING OF
THE TRACK OF AN UPPER LEVEL DISTURBANCE ACROSS THE REGION THIS
EVENING INTO MONDAY MORNING. THE NAM AND HIGH RES ARE GENERALLY 3
TO 6 HOURS QUICKER THAN THE EURO AND GFS. FOR NOW HAVE TRENDED
TAFS TO THE GFS/EURO SOLUTION. THIS WOULD FAVOR A TEMPORARY BREAK
IN PRECIP AFTER SUNSET AND THEN ANOTHER BAND OF PRECIP MOVING
ACROSS MONDAY MORNING WITH THE UPPER LEVEL DISTURBANCE/ SURFACE
LOW. BOTH GFS/ NAM SOUNDINGS SUPPORT POSSIBLE MVFR/IFR CIGS
MONDAY MORNING WITH REDUCED VISIBILITIES. GIVEN THE UNCERTAINTY IN
THE TIMING OF THE DISTURBANCE HAVE ONLY HINTED AT MVFR FOR MONDAY
MORNING.
OUTLOOK...MVFR CEILINGS ARE POSSIBLE WEDNESDAY NIGHT INTO
THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO/SITES
NEAR TERM...HATZOS
SHORT TERM...SITES
LONG TERM...AR
AVIATION...HAINES
AREA FORECAST DISCUSSION
NWS Tulsa OK
1023 AM CDT SUN MAY 1 2016
...UPDATE...
.DISCUSSION...
This morning...on a synoptic scale...an upper low was positioned
over Arizona and New Mexico while a second upper low was located
over Kansas and Nebraska. Southerly upper flow from the Arizona
upper low was converging with the northerly upper flow from the
Kansas upper low...creating a mid level frontal boundary to the
northwest of Eastern Oklahoma and Northwest Arkansas. A few
showers had developed along this boundary early this
morning...though had dissipated by mid morning as they ran into
drier air over North Central Oklahoma. Across Eastern Oklahoma and
Northwest Arkansas at mid morning...mostly clear to partly cloudy
conditions with west to northwesterly surface winds were common.
This afternoon...the mid level frontal boundary is expected to
push southeast into the CWA as the Arizona low becomes more of an
open wave as it shifts east and the Kansas low continues to
weaken. Latest HRRR runs try to develop some precip along this
boundary over Northeast Oklahoma this afternoon. For now will
continue with the current small pops northwest of Interstate
44...as the drier low level air over the region could hinder
precip reaching the ground. The better precip chances continue to
look to be tonight into Monday as the Arizona upper low moves into
the Southern Plains.
Ahead of the mid level boundary...Partly cloudy skies west to
mostly clear skies east will allow for temps to warm into the
60s-lower 70s from northwest to southeast over the CWA. As the
boundary moves into the region...cloud cover should begin to
increase with mostly cloudy conditions over the CWA expected this
evening. Also today...west to northwesterly winds 5 to 15 mph should
continue across the CWA.
Morning update will be to add minor tweaks to the afternoon
temp/pop/dewpoint/wind grinds and adjust timing of increasing sky
grids. Otherwise...current forecasts seems to be in good shape at
this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 67 48 64 46 / 10 30 10 0
FSM 75 51 68 47 / 0 40 20 10
MLC 70 50 66 45 / 0 40 10 0
BVO 64 46 63 43 / 20 40 10 0
FYV 68 48 62 42 / 0 30 20 10
BYV 70 49 62 43 / 0 30 30 10
MKO 68 48 65 44 / 0 40 10 0
MIO 65 46 63 42 / 0 30 10 0
F10 67 48 65 45 / 0 40 10 0
HHW 76 53 69 47 / 0 50 20 0
&&
.TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...20
LONG TERM....30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1140 AM EDT SUN MAY 1 2016
.SYNOPSIS...
A WAVY FRONTAL BOUNDARY ACROSS THE REGION THIS MORNING IS EXPECTED
TO LIFT NORTH AS A WARM FRONT TODAY. MEANWHILE...A SLOW MOVING COLD
FRONT APPROACHING FROM THE WEST WILL KEEP A WARM AND HUMID AIR MASS
ACROSS THE REGION THROUGH MONDAY AND MONDAY NIGHT. THE FRONT WILL
FINALLY MOVE ACROSS THE REGION ON TUESDAY. A SECOND STRONGER COLD
FRONT WILL PASS ON THURSDAY AND WILL BRING DOWN A MASS OF COLD AIR
FROM CANADA FOR LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM...PER LATEST WV IMAGERY...A SHORT WAVE TROUGH IS
BEGINNING TO MOVE EAST OF THE FORECAST AREA THIS MORNING...TAKING
THE AREA OF WIDESPREAD SHOWERS/THUNDERSTORMS ALONG WITH IT.
MEANWHILE...THE OLD CAD BOUNDARY HAS LIFTED TO NEAR THE NC/SC
BORDER...WITH SW SFC WINDS NOW BEING OBSERVED ACROSS MUCH OF UPSTATE
SC AND NORTHEAST GA. QUITE A FEW BREAKS IN THE OVERCAST HAVE BEEN
DEVELOPING ACROSS THE WESTERN HALF OF THE AREA THIS MORNING...
ALTHOUGH CUMULUS TENDS TO FILL IN PRETTY QUICKLY WITHIN THE MOIST
ENVIRONS. SBCAPE IS CURRENTLY RANGING FROM 500-1000 J/KG IN DEEPER
INTO THE WARM SECTOR (ACROSS THE SOUTHERN UPSTATE AND THE SOUTHWEST
NC MTNS). ALTHOUGH MANY AREAS WILL PROBABLY SEE A FEW PEAKS OF
SUN...IT APPEARS THE BULK OF THE DAY WILL BE MOSTLY CLOUDY. THAT
BEING THE CASE...IT STILL SEEMS THE 2000+ SBCAPE DEPICTED IN SOME
SHORT TERM GUIDANCE IS A BIT OVERDONE...BUT SUFFICIENT BUOYANCY
SHOULD NEVERTHELESS EXIST TO ALLOW FOR STRONG TO A PERHAPS A HANDFUL
OF SEVERE STORMS.
HAVING SAID THAT...IT/S NOT AT ALL CLEAR HOW CONVECTIVE TRENDS ARE
GOING TO EVOLVE LATER TODAY. WEAK SUBSIDENCE OVERSPREADING THE AREA
IN THE WAKE OF THE SHORT WAVE SHOULD PRECLUDE ANYTHING MORE THAN A
FEW ISOLATED CELLS...AT LEAST INTO EARLY AFTERNOON. OTHER THAN
TERRAIN EFFECTS...THERE WILL BE LITTLE IN THE WAY OF SOURCES OF LIFT
TO FOCUS CONVECTION. THE SURFACE BOUNDARY IS EXPECTED TO BECOME
INCREASINGLY DIFFUSE...SO IT/S NOT CLEAR AS TO WHETHER THERE WILL BE
ADEQUATE LIFT ALONG THIS BOUNDARY. SOME OF THE LATEST HIRES/
MESOSCALE GUIDANCE SUGGESTS THE CONVECTIVE LULL WILL PERSIST WELL
INTO THE AFTERNOON...WHILE THE LATEST HRRR DOES EXPAND COVERAGE OVER
THE AREA THIS EVENING...WITH THE APPROACH OF ANOTHER WEAK MID-LEVEL
SHORT WAVE TROUGH (IT/S THE ONLY HIRES MODEL THAT/S REALLY DOING
THIS). BASED UPON THE EXPECTED DEGREE OF INSTABILITY...IT SEEMS
REASONABLE THAT SCATTERED CONVECTION WILL DEVELOP NEAR THE BLUE
RIDGE THIS AFTERNOON INTO THE EVENING...AND WILL ALLOW POPS TO
INCREASE TO LIKELY THERE BY EARLY EVENING...WITH SOLID CHANCES
ADVERTISED ACROSS MUCH OF THE REMAINDER OF THE AREA. IN ADDITION TO
THE POTENTIAL FOR ISOLATED SEVERE WEATHER...WILL HAVE TO KEEP AN EYE
ON PORTIONS OF THE EASTERN UPSTATE/SC PIEDMONT AND SOUTHWEST NC
PIEDMONT FOR HYDRO ISSUES...AS SEVERAL INCHES OF RAIN HAVE FALLEN
ACROSS A FAIRLY WIDE SWATH SINCE SAT EVENING.
THE GUIDANCE SUGGESTS THAT PRECIP CHANCES WILL DIMINISH BY LATE
EVENING OR SO. TONIGHT/S LOWS WILL REMAIN SEASONALLY MILD.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300AM EDT SUNDAY...CHANCES FOR THUNDERSTORMS CONTINUE ON
MONDAY AS SOUTHWESTERLY BOUNDARY LAYER FLOW PERSISTS AROUND A
SURFACE TROUGH WEST OF THE APPALACHIANS AHEAD OF AN UPPER CENTRAL
CONUS TROUGH THAT MAKES GRADUAL EASTWARD PROGRESS. MONDAY AFTERNOON
SOUNDINGS SHOW PWATS AROUND 1.5 INCHES...MODEST INSTABILITY...AND
MODEST BULKSHEAR...CONDITIONS SIMILAR TO SATURDAY AND SUNDAY.
RESULT WILL BE CONTINUED CHANCES FOR THUNDERSTORMS ON MONDAY WITH
THE POTENTIAL FOR LOW-END SEVERE AND LOCAL FLOODING IF CELLS SHOULD
TRAIN OVER ONE AREA.
TROUGH REACHES THE CWA WITH A COLD FRONT AS UPPER SYSTEM CONTINUES
TO PROGRESS MONDAY NIGHT. LIGHTER NON-THUNDER SHOWERS MAY PERSIST
TUESDAY MORNING...DESPITE DECLINING PWATS...DUE TO FORCING FROM
UPPER SYSTEM. SOME UPSLOPE SHOWERS ON THE WEST SIDE OF THE
MOUNTAINS MAY ALSO CONTINUE INTO TUESDAY...BUT TUESDAY WILL HAVE
MOSTLY DRYER CONDITIONS AND AN END TO RAINFALL.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300AM SUNDAY...FOLLOWING PASSAGE OF MAJOR FRONT EARLY
TUESDAY...MOISTURE PLUMMETS ACROSS THE AREA AND SIGNIFICANT
ADDITIONAL PRECIP IS NOT EXPECTED WEDNESDAY THROUGH SATURDAY.
TEMPERATURES ALSO DECLINE TO 5 TO 10 DEGREES BELOW NORMAL. SOME
ISOLATED RAIN SHOWERS...AND POSSIBLY EVEN AN ISOLATED THUNDERSHOWER
ARE POSSIBLE...ESPECIALLY WEDNESDAY AFTERNOON WHEN MODELS HAVE A
SHORTWAVE TRAVERSING THE AREA BUT GREATLY REDUCED BL MOISTURE LIMITS
POTENTIAL.
IN ADDITION TO SHORTWAVES ROTATING AROUND MAJOR UPPER TROUGH
DEVELOPING OVER THE NORTHEAST CONUS...MODELS CONTINUE TO SHOW A SHOT
OF COOL CANADIAN AIR DESCENDING WITH THIS UPPER TROUGH WITH A MAJOR
COLD FROPA ON THURSDAY...AND THE COLDEST POINT IN THE FORECAST BEING
REACHED FRIDAY MORNING. GFS STILL HAS 850MB TEMPS DOWN TO -2C OVER
THE MOUNTAINS BEHIND THE FRONT...WITH THE EC SLIGHTLY WARMER AT
-1C. FRONT COULD GENERATE SOME LIGHT SHOWERS...ESPECIALLY WITH
UPSLOPE ENHANCEMENT ON THE WEST SLOPE OF THE MOUNTAINS...BUT SURFACE
TEMPERATURES SHOULD BE JUST WARM ENOUGH EVERYWHERE TO STILL PRECLUDE
ANY WINTER PRECIP. TYPES. GFS-EC AGREEMENT IS QUITE GOOD THROUGH
THURSDAY...INCLUDING DETAILS ABOUT SHORTWAVE PASSAGE ON WEDNESDAY.
COOL AIR INTRUSION FRIDAY IS SEASONALLY SHORT-LIVED WITH
TEMPERATURES REBOUNDING TO NORMAL SATURDAY AFTERNOON.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...A MIXED BAG THROUGH THE MID-MORNING HOURS
WITH VARIABLE CEILING AND VISIBILITY DEPENDING ON LOCATION RELATIVE
TO WAVES OF SHOWERS AND THUNDERSTORMS MOVING ACROSS THE REGION. MOST
PLACES WILL BE MVFR OR IFR/LIFR THROUGH THAT TIME...WITH THE THOUGHT
THAT IFR WILL PREVAIL MAINLY OVER THE NC PIEDMONT AS THE MAIN AREA
OF STORMS MOVES THROUGH. THINK THE BIGGER PROBLEM WILL BE CEILING
AND NOT VISIBILITY. MEANWHILE...THERE WILL BE SOME VFR HOLES IN THE
LOW CLOUD CEILING. WIND GENERALLY SHOULD BE SE TO THE SOUTH OF AN
OLD BOUNDARY RUNNING ROUGHLY ALONG I-85...AND NORTHEAST TO THE NORTH
OF THE BOUNDARY. THIS IS EXPECTED TO WASH OUT WITH SE WIND TAKING
SHAPE AT ALL PLACES BY MID MORNING. THE LATEST GUIDANCE FROM
CONVECTION ALLOWING MODELS SUGGESTS THERE WILL BE A BIT OF A LULL IN
THE WAKE OF THE CURRENT ACTIVITY...THEN ANOTHER DEVELOPMENT OF
STORMS IN THE MIDDLE PART OF THE DAY. THE TSRA CHANCE WILL BE
HANDLED WITH A TEMPO AT ALL SITES. ENDED PRECIP/RESTRICTION THREAT
EVERYWHERE BY 00Z BASED ON GUIDANCE SHOWING A WAVE MOVING PAST
AROUND THAT TIME. MOST DETAIL BEYOND 00Z MONDAY WAS ELIMINATED FOR
BREVITY.
OUTLOOK...UNSETTLED WEATHER/OCCASIONAL CONVECTION/RESTRICTIONS ARE
EXPECTED TO CONTINUE INTO EARLY NEXT WEEK...AS A FRONT BECOMES
STALLED NEAR THE AREA. DEFINITIVE DRYING DOES NOT APPEAR LIKELY
UNTIL AT LEAST MID-WEEK.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-12Z
KCLT MED 70% HIGH 100% HIGH 100% HIGH 100%
KGSP MED 68% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 81% HIGH 100% HIGH 100% HIGH 94%
KHKY LOW 53% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 83% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 88% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK:
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...JDL/PM
SHORT TERM...WJM
LONG TERM...WJM
AVIATION...PM
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1106 AM CDT SUN MAY 1 2016
.UPDATE...
CURRENTLY...SHOWERS AND THUNDERSTORMS CONTINUE TO SKIRT MONROE
COUNTY MISSISSIPPI. THESE SHOWERS ARE MOVING ALONG AN OLD OUTFLOW
BOUNDARY. EXPECT THIS TREND TO CONTINUE INTO THE AFTERNOON HOURS.
MEANWHILE...THE COLD FRONT CURRENTLY STRETCHES FROM NEAR PARIS
TENNESSEE TO NEAR STUGGART ARKANSAS. LATEST HRRR SHOWS DEVELOPMENT
OF THUNDERSTORMS ALONG AND AHEAD OF THE FRONT THIS AFTERNOON.
LATEST KNQA RADAR SHOWS THE FIRST SHOWER MAY BEGINNING TO GO UP
OVER LEE COUNTY ARKANSAS. WILL UPDATE TO RAISE POPS IN THE
VICINITY OF THE FRONT. THE AIRMASS IS PRETTY UNSTABLE AHEAD OF THE
FRONT AND WOULD NOT BE SURPRISED TO SEE A STRONG OR SEVERE STORM
AS WELL.
KRM
&&
.DISCUSSION... /ISSUED 404 AM CDT SUN MAY 1 2016/
THERE IS SOME PATCHY FOG ACROSS THE MIDSOUTH...BUT SO FAR WE HAVE
NOT SEEN ANYTHING THAT WARRANTS THE NEED FOR AN ADVISORY. DEW
POINT DEPRESSIONS ARE SMALLEST NEAR THE TENNESSEE RIVER AND
KENTUCKY STATE LINE. WILL CONTINUE TO MONITOR CONDITIONS AND
UPDATE LATER THIS MORNING IF NEEDED. TEMPERATURES ARE MOSTLY IN
THE MIDDLE 60S THIS MORNING...AND EXPECTED TO FALL INTO THE LOW
60S BY SUNRISE. THERE WERE A FEW THUNDERSTORMS ON RADAR EARLIER IN
THE NIGHT...BUT AS OF 3 AM...ONLY ISOLATED SHOWERS REMAIN. SHORT
TERM HIGH RESOLUTION GUIDANCE...WHICH HAS PERFORMED WELL FOR THE
LAST FEW DAYS...SUGGESTS THE WEAKENING TREND WILL CONTINUE THROUGH
SUNRISE.
A COLD FRONT IS MOVING ACROSS THE MIDSOUTH. IT IS CURRENTLY
APPROACHING KENNETT MISSOURI AND WYNNE ARKANSAS. THIS FEATURE IS
EXPECTED TO STALL LATER THIS EVENING OR OVERNIGHT ACROSS NORTH
MISSISSIPPI INTO CENTRAL TENNESSEE. AHEAD OF THE FRONT MAINLY...IN
WEST TENNESSEE AND NORTH MISSISSIPPI SHOWERS AND THUNDERSTORMS
MAY REDEVELOP THIS AFTERNOON. STRONG OR SEVERE THUNDERSTORMS ARE
NOT EXPECTED. COVERAGE MAY BE LIMITED UNTIL LATE AFTERNOON WHEN A
MID LEVEL TROUGH WILL APPROACH THE MISSISSIPPI RIVER VALLEY
PROVIDING A BIT MORE UPPER LEVEL SUPPORT. THE HIGHEST RAIN CHANCES
WILL LIKELY RETURN TONIGHT INTO EARLY MONDAY...ESPECIALLY IN NORTH
MISSISSIPPI AS THE TROUGH CONTINUES EAST. MONDAY SHOULD BE OUR
LAST DAY OF SHOWERS AND THUNDERSTORMS. SEVERE STORMS ARE NOT
EXPECTED.
SYNOPTICALLY...WE WILL SEE A BLOCKING PATTERN SET UP EARLY NEXT
WEEK AND REMAIN IN PLACE FOR SEVERAL DAYS....POSSIBLY INTO NEXT
WEEKEND. AS A RESULT...EXPECT BENIGN WEATHER. CLEAR TO PARTLY
CLOUDY SKIES AND MILD TEMPERATURES ARE EXPECTED FOR THE UPCOMING
WORK WEEK.
TEMPERATURES WILL TURN COOLER EARLY THIS WEEK. HIGHS MONDAY
SHOULD TOP OUT ON THE LOW 70S...AND MAY NOT CLIMB OUT OF THE 60S
IN DURING THE MIDDLE PART OF THE WORK WEEK. THE COOLEST
TEMPERATURES OVER THE NEXT WEEK OR SO SHOULD OCCUR WEDNESDAY OR
THURSDAY MORNING WHEN SOME LOCATIONS COULD DIP INTO THE MIDDLE
40S. TEMPERATURES WILL TREND SLIGHTLY WARMER FRIDAY INTO NEXT
WEEKEND.
30
&&
.AVIATION...
12Z TAF CYCLE
VFR CONDS EXPECTED TO PREVAIL THROUGHOUT THE ENTIRE PERIOD. A
STALLED FRONT CURRENTLY RESIDES JUST WEST OF THE MS RIVER. WINDS
ARE CURRENTLY LIGHT FROM A SOUTHERLY DIRECTION AT ALL BUT KJBR
WHERE WINDS ARE WEST NORTHWESTERLY. WINDS WILL GRADUALLY BECOME
MORE WESTERLY THIS AFTERNOON AT ALL TERMINALS BUT SHOULD REMAIN
BELOW 8 KTS. EXPECT CLOUDS TO INCREASE AS CIGS LOWER LATE IN THE
PERIOD WITH VCSH INCLUDED AS PRECIP MOVES INTO THE REGION UNDER SW
FLOW ALOFT.
ZDM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS EUREKA CA
303 PM PDT SUN MAY 1 2016
.SYNOPSIS...A HIGH PRESSURE RIDGE EXTENDING ACROSS THE REGION WILL
MAINTAIN DRY AND WARMER CONDITIONS ACROSS THE AREA THROUGH MONDAY.
TEMPERATURES WILL DECREASE SLIGHTLY MONDAY AND TUESDAY AS A COLD
FRONT APPROACHES AND MOVES THROUGH THE AREA INCREASING THE CHANCES
FOR A FEW SHOWERS AND INCREASING CLOUDINESS. A LOW PRESSURE SYSTEM
MAY MOVE INTO NORTH CENTRAL CA BRINING THUNDERSTORM CHANCES FOR
EASTERN TRINITY COUNTY THROUGH NEXT WEEK.
&&
.DISCUSSION...CLEAR TO PARTLY CLOUDY SKIES WILL CONTINUE ACROSS
THE REGION AS A HIGH PRESSURE RIDGE PERSIST ACROSS THE AREA...AND
LIGHT OFFSHORE FLOW KEEPS THE COAST WARM AND FOG/LOW CLOUD FREE.
THE OFFSHORE WIND COMPONANT WILL CEASE BY MONDAY FOR A RETURN OF
LOW CLOUDS AND LIKELY FOGGY CONDITIONS AT LEAST DURING THE NIGHTS
AND MORNINGS. A WEAK COLD FRONT AND GENERAL TROUGHINESS WILL
APPROACH AND MOVE THROUGH THE REGION MONDAY AND TUESDAY INCREASING
CLOUDINESS AND A SLIGHT CHANCE TO CHANCE FOR SHOWERS MOVING ACROSS
PORTIONS OF THE REGION. CLOUDINESS WILL INCREASE MONDAY AND
TUESDAY WHICH WILL COOL TEMPERATURES SLIGHTLY ACROSS THE REGION.
PATCHY FOG MAY DEVELOP ACROSS PORTIONS OF THE COASTAL AREAS AND
INLAND VALLEYS THROUGH MID WEEK. THE UPPER TROUGH MAY MORPH INTO
A CUT OFF LOW THAT THE GFS HAS MOVING SLOWLY INTO THE BAY AREA BY
THURSDAY. THIS WILL BRING SLIGHTLY ELEVATED CHANCES OF
THUNDERSTORMS AND PERSISTENT SHOWER CHANCES TO THE INTERIOR
MOUNTAINS MAINLY EAST OF WEAVERVILLE. OTHERWISE SEASONAL
TEMPERATURES AND FAIRLY NICE SPRING WEATHER SHOULD CONTINUE.
&&
.AVIATION...VFR WILL PREVAIL THROUGH THE REMAINDER OF THE DAY WITH
RELATIVELY LIGHT WINDS ACROSS THE REGION. OFFSHORE WINDS SHOULD BE
WEAKER TONIGHT SO CEILING DEVELOPMENT ALONG PARTS OF THE COAST WILL
NOT BE OUT OF QUESTION. VFR SHOULD CONTINUE ACROSS INTERIOR
LOCATIONS OVERNIGHT. MOUNTAIN SHOWERS WILL BE POSSIBLE MONDAY
AFTERNOON OTHERWISE EXPECT UPPER LEVEL CLOUDS TO INCREASE LATE IN
THE TAF PERIOD. KML
&&
.MARINE...STEEP WAVES CONTINUED TO SUBSIDE TODAY AS THE RELAXED
PRESSURE GRADIENT ALLOWED WINDS TO DECREASE. WINDS WILL BECOME LIGHT
AND SOUTHERLY ON MONDAY AS A SURFACE LOW FEATURE DRIFTS NORTHWARD.
THIS WILL MAINTAIN LIGHT TO MODERATE WINDS THROUGH THE EARLY HALF OF
THE WEEK BEFORE A RIDGE OF HIGH PRESSURE OFFSHORE BUILDS TOWARDS THE
WEST COAST. THIS WILL PINCH THE GRADIENT ONCE AGAIN AND BRING A
RETURN OF MODERATE TO FRESH NORTHERLY WINDS FOR THE LATE HALF OF THE
WEEK. A NORTHWESTERLY SWELL WILL OTHERWISE DOMINATE THE SEA STATE
FOR THE EARLY HALF OF THE WEEK WITH OVERALL WAVE HEIGHTS PREDICTED
TO REMAIN BELOW 10 FT. STEEP WAVES WILL BUILD ONCE THE WINDS START
INCREASING LATE IN THE WEEK WITH A SMALL LONG PERIOD SWELL EXPECTED
TO PROPAGATE THE WATERS THURSDAY INTO THE WEEKEND. KML
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
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HTTP://WWW.TWITTER.COM/NWSEUREKA
FOR FORECAST ZONE INFORMATION
SEE FORECAST ZONE MAP ONLINE:
HTTP://WWW.WEATHER.GOV/EUREKA/ZONEMAP.PNG
[top]
Area Forecast Discussion
National Weather Service Sacramento CA
250 PM PDT SUN MAY 1 2016
.Synopsis...
Threat of afternoon showers and thunderstorms continues over the
mountains into Tuesday then a more widespread chance Wednesday
into Friday. Cooling to near normal midweek.
&&
.Discussion...
Thunderstorms and showers have developed along the western Sierra
slopes this afternoon. Current radar shows that most of the
thunderstorms are in El Dorado county and southward along the
Sierra. Latest HRRR run is showing that showers/thunderstorms will
gradually spread northward along the Sierra...reaching up to
around the Quincy-Chester area. HRRR also shows that
showers/thunderstorms could move into the foothills, especially
the Motherlode region along with some showers possible in the
Northern San Joaquin Valley this evening around Stockton and
Modesto. All shower activity should diminish by 9-10 pm tonight.
In the meantime, if you hear thunder, stay indoors for shelter to
avoid dangerous lightning and possible hail.
Meso low weakens over NorCal Monday although some lingering
chances for showers/thunderstorms possible along the higher
elevations of the Sierra. By Tuesday, a deep upper trough over the
Eastern Pacific Ocean will move into the West Coast which will
continue the threat of afternoon mountain showers and
thunderstorms. High temps trend down slightly on Tuesday as
synoptic cooling and onshore flow gradually increase over Interior
NorCal.
More notable cooling (5-10 degrees) on Wednesday as the
center of the low gets closer to interior NorCal. Valley highs
will be around the mid 70s with 50s and 60s along foothills and
mountains. Chance of showers will become more widespread on
Wednesday, covering much of our CWA. Instability with this low
will keep a slight chance of thunderstorm development in the mix,
too. JBB
&&
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)
Forecast models are in decent agreement as to the position and
timing of the upper level low track and progression starting at the
beginning of the long term forecast period. The high amplitude
trough of low pressure is a bit quicker as advertised by the GFS
heading into late Wednesday night to early Thursday morning, while
the ECMWF has the arrival into NorCal more into the early to mid
morning hours on Thursday. In either scenario, the incoming storm
system will bring the needed lift behind enough moisture to bring
showers and thunderstorm chances for the entire forecast area. The
system will not move very quick, and cool temperatures along with
chances for showers and thunderstorms will continue through next
weekend.
A cool down of temperatures is expected with a return to near normal
high temperatures in the low to mid 70s in the valley, 50s to 60s in
the foothills, and the low to mid 40s in the higher elevations on
Thursday and Friday. Temperatures should return to slightly above
normal temperatures in the valley next weekend.
&&
.AVIATION...
VFR conditions are expected at the terminals for the next 24
hours. Thunderstorms over the Sierra Cascade range this afternoon
and evening. Light winds.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1029 AM PDT SUN MAY 1 2016
.SYNOPSIS....OFFSHORE WINDS WILL CONTINUE TODAY...RESULTING IN
SUNNY AND WARM CONDITIONS IN MOST AREAS. COASTAL FOG AND LOW
CLOUDS WILL LIKELY RETURN BY LATE TODAY OR TONIGHT. SEASONABLE
AND DRY WEATHER IS FORECAST MONDAY AND TUESDAY. A WEATHER SYSTEM
WILL APPROACH CALIFORNIA BY THE MIDDLE OF THE WEEK...BRINGING A
CHANCE OF SHOWERS FROM LATE WEDNESDAY THROUGH THE END OF THE
WEEK...ALONG WITH COOLER THAN NORMAL TEMPERATURES.
&&
.DISCUSSION...AS OF 8:45 AM PDT SUNDAY...CLEAR START TO THE DAY
WITH A MODERATE OFFSHORE FLOW IN PLACE. N-TO-S GRADIENT RIGHT NOW
IS OVER 2 MB WHILE W-TO-E FLOW IS SLIGHTLY FROM THE EAST. AS THE
PREVIOUS DISCUSSION MENTIONED, MODELS ARE INDICATING A SOUTHERLY
PUSH UP THE COAST TODAY ALTHOUGH CURRENT SATELLITE DOES NOT SHOW
ANY CLOUDS EVEN UP TO SLO COUNTY. 14Z RUN OF THE HRRR DOES
INDICATE SOUTHERLY WINDS WILL SET UP OVER THE NEXT FEW HOURS, SO
WILL KEEP A CLOSE EYE ON THE SATELLITE TO SEE IF IT DOES
MATERIALIZE.
CURRENT FORECAST ON TRACK SO NO UPDATES PLANNED AT THE MOMENT.
.PREVIOUS DISCUSSION...SKIES ARE CLEAR ACROSS OUR ENTIRE FORECAST
AREA EARLY THIS MORNING AS LIGHT OFFSHORE FLOW CONTINUES. CURRENT
TEMPERATURES ARE GENERALLY WARMER THAN 24 HOURS AGO AND IN SOME
CASES SEVERAL DEGREES WARMER. FORECAST GUIDANCE INDICATES HIGH
TEMPERATURES TODAY WILL BE ABOUT FIVE DEGREES WARMER THAN
YESTERDAY. HOWEVER...MODELS FORECAST AN END TO OFFSHORE FLOW TODAY
ALONG WITH THE DEVELOPMENT OF SOUTHERLY FLOW ALONG THE COAST. THIS
DOES NOT LOOK LIKE A CLASSIC "SOUTHERLY SURGE" SCENARIO...SINCE
LOW CLOUDS DO NOT ALREADY EXIST TO OUR SOUTH NEAR POINT
CONCEPTION. WHAT`S MORE LIKELY TO HAPPEN IS THAT LOW CLOUDS AND
FOG WILL FORM IN COASTAL AREAS FROM MONTEREY BAY SOUTH BY EARLY
AFTERNOON...AND THEN MOVE NORTH UP ALONG THE REST OF OUR COAST
LATE THIS AFTERNOON AND EVENING. THIS MAKES FOR A DIFFICULT
TEMPERATURE FORECAST TODAY FOR COASTAL AREAS SINCE THE TIMING OF
THE SOUTHERLY WIND ONSET AND COASTAL FOG DEVELOPMENT WILL HAVE A
BIG IMPACT ON TEMPERATURES. MOST LIKELY SCENARIO IS FOR COOLING TO
OCCUR IN LOCATIONS LIKE BIG SUR AND SANTA CRUZ WHILE OTHER COASTAL
AREAS WILL BE AS WARM OR WARMER THAN YESTERDAY.
ANOTHER ITEM TO WATCH TODAY IS A SHORTWAVE TROUGH CURRENTLY OVER
SOUTHEAST OREGON THAT IS ROTATING AROUND A LONGWAVE TROUGH
CENTERED OVER THE DESERT SW. THIS SHORTWAVE IS FORECAST TO ROTATE
INTO NORTHERN AND CENTRAL CALIFORNIA LATER TODAY. THE ECMWF KEEPS
ALL PRECIP ASSOCIATED WITH THIS SHORTWAVE TO OUR EAST...MAINLY OVER
THE SIERRA NEVADA. HOWEVER...BOTH THE 00Z NAM AND 00Z GFS
FORECAST ISOLATED SHOWERS ALONG THE EASTERN FRINGES OF OUR
FORECAST AREA LATE THIS AFTERNOON AND EARLY THIS EVENING. HAVE
THEREFORE ADDED SLIGHT CHANCE POPS TO FAR EASTERN ALAMEDA...SANTA
CLARA...AND SAN BENITO COUNTIES FOR LATER TODAY.
DRY AND MILD WEATHER IS FORECAST FOR MONDAY AND TUESDAY. ONSHORE
FLOW WILL LIKELY MAINTAIN AT LEAST AREAS OF NIGHT AND MORNING LOW
CLOUDS AND TEMPERATURES WILL BE NEAR NORMAL.
AN UPPER TROUGH CURRENTLY SEEN ON SATELLITE IMAGERY OFFSHORE ALONG
145W IS FORECAST TO GRADUALLY APPROACH THE CALIFORNIA COAST OVER
THE NEXT THREE DAYS AND BEGIN TO GENERATE SHOWER CHANCES ACROSS
OUR AREA BY LATE WEDNESDAY. BOTH THE GFS AND ECMWF FORECAST A
CUTOFF LOW TO DEVELOP NEAR SAN FRANCISCO BY THURSDAY...WITH THAT
LOW THEN PROJECTED TO DROP SOUTHEAST AND TRACK ACROSS SOUTHERN
CALIFORNIA BY LATE FRIDAY AND FRIDAY NIGHT. THUS...SHOWER CHANCES
WILL CONTINUE THROUGH THE END OF THE WEEK AND PROBABLY INTO NEXT
WEEKEND AS WELL. GIVEN THE UNPREDICTABILITY OF CUTOFF LOW
MOVEMENT...IT`S DIFFICULT TO PINPOINT WHERE SHOWER CHANCES WILL BE
GREATEST DURING THE SECOND HALF OF THE WEEK. ISOLATED THUNDERSTORMS
MAY ALSO OCCUR...BUT WILL WAIT TO ADD THUNDERSTORMS TO THE
FORECAST UNTIL CONFIDENCE INCREASES ON THE TIMING AND TRACK OF THE
UPPER LOW. IN ADDITION TO PRECIPITATION CHANCES...THIS UPPER LOW
WILL RESULT IN COOLER THAN NORMAL CONDITIONS ACROSS MOST OF OUR
AREA DURING THE SECOND HALF OF THE WEEK.
&&
.AVIATION...AS OF 10:30 AM PDT SUNDAY...DRY OFFSHORE FLOW KEEPING
VFR TODAY. THE ONE FLY IN THE OINTMENT IN THE FORECAST IS A
POSSIBLE SOUTHERLY SURGE LATER TODAY. LATEST NAM AND WRF SHOW A
SOUTHERLY SURGE IMPACTING KMRY/KSNS...POSS MAKING IT INTO SF BAY
OVERNIGHT. CONF IS MARGINAL.
VICINITY OF KSFO...VFR.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY TERMINALS...VFR BECOMING MVFR LATE THIS EVENING AND
OVERNIGHT.
&&
.MARINE...AS OF 8:45 AM PDT SUNDAY...HIGH PRESSURE OVER THE
EASTERN PACIFIC WILL KEEP NORTHERLY WINDS OVER THE COASTAL WATERS
TODAY. LOCALLY GUSTY WINDS WILL BE POSSIBLE OVER THE OUTER WATERS
NORTH OF POINT REYES. SOUTHERLY WINDS WILL DEVELOP LATE TONIGHT
AND EARLY MONDAY. A MODERATE SWELL WILL MIX WITH A SMALLER LONG
PERIOD SOUTHERLY SWELL THIS WEEK.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: BELL/DYKEMA
AVIATION: SIMS
MARINE: SIMS
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AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1121 AM MDT SUN MAY 1 2016
UPDATED AVIATION SECTION
.UPDATE...
ISSUED AT 823 AM MDT SUN MAY 1 2016
WEB CAMS INDICATE ACCUMULATING SNOW LEVEL IS SITTING AROUND 6800
FEET ACROSS THE FOUR CORNERS VALLEYS THIS MORNING...BUT IR
SATELLITE SHOWS CLOUD TOPS WARMING AND TEMPERATURES RISING AT
LOCATIONS FROM THE NORTHERN SAN JUANS AND NORTH. WITH THE CORE OF
THE CLOSED LOW SPREADING ACROSS THE SOUTHERN VALLEYS...NOT
EXPECTING SNOW LEVEL TO RISE MUCH OVER THE NEXT COUPLE OF HOURS
OVER THE VALLEYS...BUT FURTHER NORTH THE ACCUMULATING SNOW LEVEL
IS EXPECTED TO BE CLOSER TO 8000 FEET.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
MORE PRECIP IN THE FORECAST TODAY AS THE NEXT AREA OF LOW PRESSURE
CONTINUES TO MOVE TOWARDS THE FOUR CORNERS. AT THIS HOUR...RADAR
MOSAIC ALREADY SHOWING SOME RETURNS JUST TO THE SOUTH OF THE CO/NM
BORDER WHILE IR SATELLITE IS SHOWING ENHANCED CLOUD TOPS OVER THE
SAME REGION. THE HRRR AND RAP13 ARE IN VERY GOOD AGREEMENT WITH
PRECIP BEGINNING FOR THE SOUTHERN VALLEYS JUST BEFORE DAYBREAK
TODAY WITH PRECIP REACHING THE SAN JUANS BETWEEN 7 AND 8 AM. SOME
SNOW ACCUMULATION WILL OCCUR TODAY...MAYBE AS MUCH AS 4 TO 6
INCHES BUT ONLY FOR THE HIGHEST ELEVATIONS. MOUNTAIN PASSES MAY
SEE SOME MINOR ACCUMULATION BEFORE MELTING AS THE DAY MOVES ON.
TOYED WITH IDEA OF ISSUING SOME ADVISORIES BUT A FEW THINGS
STICKING OUT. THE CORE OF THIS LOW PRESSURE CENTER IS RELATIVELY
WARM AT -20C WHILE H7 TEMPS OF -4C AT 6AM WILL WARM TO -1 TO -2C
BY NOON. ALSO...PRECIP LOOKS TO FALL DURING DAYTIME HOURS SO ROAD
SURFACES WILL BE WARM ENOUGH TO MELT MOST SNOW THAT FALLS. IF
NOT...SOME SLUSHY PATCHES CAN BE EXPECTED. THE LAST FEW SYSTEMS
ALSO BROUGHT SNOW TO VARIOUS AREAS OF OUR CWA BUT IMPACTS WERE
MINIMAL. THIS EVENT LOOKS TO BE SIMILAR SO WILL HOLD OFF FOR NOW.
DAY SHIFT CAN KEEP AN EYE ON HOW THINGS TRANSPIRE AND ISSUE A
HIGHLIGHT IF NEEDED/REQUIRED.
BY LATE THIS AFTERNOON...PRECIP WILL HAVE REACHED JUST SOUTH OF
THE I-70 CORRIDOR BUT EXPECT THIS PRECIP TO BE MORE SPOTTY IN
NATURE. BY EARLY MONDAY MORNING...WIDESPREAD RAIN/SNOW LOOKS TO
END AND BECOME MUCH MORE ISOLATED IN NATURE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 327 AM MDT SUN MAY 1 2016
A FEW MINOR CHANGES TO THE LONG TERM BUT THE GIST REMAINS THE
SAME. RESIDUAL MOISTURE AND SOME WEAK UPPER LEVEL SUPPORT WILL
LEND ITSELF TO FORM SOME AFTERNOON SHOWERS AND STORMS MONDAY BUT
BY TUESDAY...HIGH PRESSURE BUILDS IN BRINGING A RETURN TO WARMER
CONDITIONS AND SUNNY SKIES. BOTH GFS/NAM PAINT SOME SHOWERS OVER
THE SAN JUANS TUESDAY EVENING BUT THESE WILL LIKELY BE POP AND
DROP SHOWERS OR STORMS THAT WON`T POSE MUCH OF A THREAT. AS THIS
OCCURS...YET ANOTHER LOW PRESSURE MOVES ACROSS CALIFORNIA AND
TAKES AIM AT OUR CWA. A WARM FRONT WILL BRING SOME SHOWERS AND
STORMS TO THE AREA THURSDAY EVENING AHEAD OF THE LOW PRESSURE
SYSTEM. CLOUDS WILL INCREASE THROUGH THE DAY FRIDAY WITH SOME
GUSTY WINDS POSSIBLE DOWN SOUTH BEFORE THE LOW SETS UP OVER THE
CENTRAL GREAT BASIN AND BRINGS MORE PRECIP TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1121 AM MDT SUN MAY 1 2016
CLOSED LOW OVER THE FOUR CORNERS WILL CONTINUE BRINGING
PRECIPITATION TO THE LOWER HALVES OF EASTERN UTAH AND WESTERN
COLORADO TODAY. THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE
FOUR CORNERS BETWEEN 18Z AND 00Z. CONDITIONS WILL SLOWLY IMPROVE
AFTER 06Z TONIGHT...BUT CIGS ARE EXPECTED TO REMAIN LOW THROUGH
14Z MONDAY AS LOW STRATUS HANGS AROUND.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JAM
SHORT TERM...TGR
LONG TERM...TGR
AVIATION...JAM
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
350 PM EDT SUN MAY 1 2016
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A MID/UPPER LAYER
WESTERLY FLOW PATTERN IN PLACE ACROSS THE GULF OF MEXICO AND
FLORIDA PENINSULA. SOUTHERN STREAM JET CROSSES OVER NORTHERN
MEXICO AND ACROSS THE GULF...WITH THE NOSE OF THE MAIN JETSTREAK
OVER OUR REGION. NORTHERN STREAM JET IS IN FAIRLY CLOSE
PROXIMITY...CROSSING OVER THE SOUTHERN/CENTRAL PLAINS...TO THE
MID MS AND OHIO VALLEYS. 01/12Z KTBW SOUNDING PROFILE SAMPLED
THESE WINDS ALOFT WELL...SHOWING A DEEP LAYER WEST FLOW ABOVE
700MB.
AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO
THE WEST OVER THE FLORIDA PENINSULA AND EASTERN GULF OF MEXICO. A
COMPLEX FRONTAL SYSTEM REMAINS WELL TO OUR NORTH AND NORTHWEST
FROM SOUTHERN TEXAS TO THE LOWER MS VALLEY AND NORTHEAST INTO THE
OHIO VALLEY. CLUSTERS OF SHOWERS AND STORMS ARE FORMING AND
ONGOING IN ADVANCE OF THIS FRONT...BUT WILL ALSO REMAIN WELL
REMOVED FROM OUR FORECAST AREA. THE ONLY IMPACT FROM THESE STORMS
THAT WE MAY SEE SOME INCREASE IN HIGH CLOUDS LATER THIS EVENING OR
OVERNIGHT ACROSS THE NORTHERN NATURE COAST ZONES ASSOCIATED WITH
ANVIL BLOWOFF ADVECTING DOWNSTREAM IN THE SYNOPTIC UPPER FLOW.
SEA-BREEZE HAS FORMED ALONG THE COAST AND WE ARE NOW SEEING THE
CONVERGENCE ZONE BETWEEN THIS WEST-COAST SEA-BREEZE AND THE
FLORIDA EAST COAST SEA-BREEZE SET UP ALONG AND JUST EAST OF THE
I-75 CORRIDOR. MID-AFTERNOON VISIBLE SATELLITE IMAGERY IS SHOWING
THE CUMULUS FIELD IN THIS REGION BECOMING A BIT MORE DEFINED.
ALTHOUGH...AS OF NOW...NOT SEEING ANYTHING ON RADAR AS THESE
COLUMNS ARE SHALLOW AND STILL TRAPPED UNDERNEATH A STRONG CAPPING
SUBSIDENCE INVERSION SHOWN WELL ON THE MORNING 12Z KTBW SOUNDING.
THIS CAPPING INVERSION WILL HOLD BACK MUCH OF THE CONVECTION THIS
EVENING. HOWEVER...WHERE MOISTURE POOLING IS GREATEST ALONG THE
CONVERGING SEA-BREEZE BOUNDARIES...ML CAPE MAY BECOME SUFFICIENT
TO BRIEFLY OVERCOME THIS CAPPING LAYER AND SUPPORT ISOLATED TO
WIDELY SCT STORMS AFTER 21Z. THE LAST FEW RUNS OF THE HRRR ARE
ALREADY WAY TO AGGRESSIVE WITH CONVECTION COMPARED TO
REALITY...SO UNFORTUNATELY CAN NOT USE THIS USUALLY RELIABLE
GUIDANCE TO HELP WITH THE SHORT TERM CONVECTIVE TRENDS. FEEL THE
CURRENT FORECAST IS THE BEST COURSE OF ACTION FOR NOW. EXPECT A
FEW STORMS TO FINALLY BREAK THIS CAP WITHIN THE ZONE DESCRIBED
ABOVE...MOST LIKELY INITIATING BETWEEN 21-22Z...AND THEN LINGER
FOR A FEW HOURS THIS EVENING BEFORE DISSIPATING.
&&
.SHORT TERM (TONIGHT THROUGH MONDAY)...
TONIGHT...WITH THE LATE START TO THE ISOLATED CONVECTION...WOULD
ANTICIPATE THE CELLS THAT DO DEVELOP TO LINGERING FOR A FEW HOURS
PAST SUNSET. WILL KEEP A LOW CHANCE POP IN THE FORECAST FOR THIS
FAVORED CONVERGENCE ZONE UNTIL 03Z...AND THEN ALLOW THE REST OF
THE OVERNIGHT TO BE DRY REGION-WIDE. A FEW POCKETS OF FOG ARE
QUITE LIKELY IN THE HOURS BEFORE DAWN...BUT NEITHER THE SREF OR
STATISTICAL GUIDANCE ARE SUGGESTING WE WILL HAVE ANY SIGNIFICANT
VIS ISSUES FOR THE MORNING COMMUTE. GIVEN THAT THE COVERAGE OF
RAINFALL TODAY SHOULD BE LOW...WOULD AGREE WITH THE NWP. LOW
TEMPERATURES TONIGHT WILL BE SEASONABLY WARM WITH UPPER 60S INLAND
AND LOWER 70S ALONG THE COAST.
MONDAY...
OVERALL THE SYNOPTIC PATTERN IS NOT ALL THAT DIFFERENT FROM
TODAY. THE MOST INFLUENTIAL DIFFERENCE MAY BE THAT THE MID/UPPER
LEVEL ENVIRONMENT IS SLIGHTLY MORE MOIST AND HENCE A BIT LESS
HOSTILE TOWARD DEEP CONVECTION. ALSO...THERE DOES STILL SEEM TO BE
A HINT OF THE CAPPING INVERSION IN THE FORECAST SOUNDINGS...BUT AT
LEAST FOR NOW...IT APPEARS LESS DRAMATIC. BOTH OF THESE FACTORS
SHOULD CONTRIBUTE TO A BIT HIGHER COVERAGE OF LATE DAY STORMS
ACROSS THE SAME FAVORED CONVERGENCE ZONE RUNNING ALONG AND JUST
EAST OF THE I-75 CORRIDOR. INHERITED FORECAST HAS 30-40% POPS IN
THIS ZONE...AND THEN TAPERS RAIN CHANCES BACK TO 10-20% AT THE
COAST. BASED ON THE EXTENT OF THE 12Z GUIDANCE CYCLE...DO NOT SEE
MUCH REASON TO MAKE SIGNIFICANT CHANGES. ANY CONVECTION ON MONDAY
WILL AGAIN BE SUPPRESSED BY THE ENVIRONMENT ALOFT UNTIL LATE IN
THE AFTERNOON OR EARLY EVENING...WHICH SHOULD AGAIN ALLOW
LOCATIONS AWAY FROM THE IMMEDIATE COAST TO PUSH 90 FOR HIGH
TEMPERATURES. AT THE BEACHES TEMPS HOLD IN THE 80S WITH THE
DEVELOPMENT ONSHORE FLOW DURING THE AFTERNOON.
ENJOY YOUR SUNDAY EVENING EVERYONE!
&&
.MID/LONG TERM (TUESDAY THROUGH NEXT SUNDAY)...
A SLOW MOVING FRONTAL BOUNDARY WILL BE POSITIONED TO THE NORTH OF
THE AREA LATE MONDAY INTO TUESDAY. SOUTH OF THIS BOUNDARY...THERE
WILL BE A GRADUAL INCREASE IN LOW AND MID-LEVEL MOISTURE ACROSS
THE FLORIDA PENINSULA AS WINDS BECOME MORE SW AS SURFACE RIDGE
BEGINS TO PUSH EAST. INCREASING MOISTURE AND COOLER TEMPERATURES
ALOFT (H5 TEMPS AROUND -12C) SHOULD CREATE AN ENVIRONMENT
FAVORABLE FOR FAIRLY DECENT COVERAGE OF AFTN SHOWERS AND STORMS
ALONG SEABREEZE/BOUNDARY COLLISIONS. HIGH TEMPERATURES WILL REMAIN
WARM WITH MID TO UPPER 80S AREA WIDE.
LATE TUESDAY INTO WEDNESDAY A STRONG UPPER LEVEL LOW WILL PUSH OUT
OF THE GREAT LAKES HELPING TO INDUCE SIGNIFICANT TROUGHING ACROSS
THE EASTERN UNITED STATES FOR THE REST OF THE WEEK. AT THE SAME
TIME...ANOTHER SHORTWAVE ACROSS THE CENTRAL PLAINS IS FORECAST TO
MOVE SE INTO THE DEEP SOUTH. THIS SHORTWAVE WILL BE THE CATALYST FOR
GIVING THIS FRONT THE PUSH IT NEEDS TO CLEAR OUT OF THE SOUTHEASTERN
U.S. DEPENDING ON THE INTENSITY OF THIS SHORTWAVE...SOME STRONG TO
SEVERE THUNDERSTORM POTENTIAL MAY EXIST...THOUGH UNCERTAINTY REMAINS
AS TO THE TIMING AND INTENSITY OF BOTH SURFACE AND UPPER LEVEL
FEATURES SO STAY TUNED. EITHER WAY...SHOWERS AND THUNDERSTORMS WILL
BE LIKELY ACROSS THE AREA AS THE FRONT PUSHES THROUGH WEDNESDAY.
THE UPPER LEVEL PATTERN CONTINUES TO AMPLIFY THROUGHOUT THE REST OF
THE WEEK BEHIND THE FRONT AND COOLER...DRIER CONTINENTAL AIR WILL
FILTER IN TO THE PENINSULA BEGINNING THURSDAY AND CONTINUING THROUGH
THE WEEKEND. PLEASANT WEATHER EXPECTED THU-SAT WITH TEMPERATURES
NEAR OR SLIGHTLY BELOW NORMAL WITH NO RAIN AND LIMITED CLOUD COVER.
HIGH TEMPERATURES EXPECTED BETWEEN UPPER 70S TO LOW/MID 80S FROM
NORTH TO SOUTH WITH OVERNIGHT LOWS MID/UPPER 50S...LOW/MID 60S
CLOSER TO THE COAST. TEMPERATURES LOOK TO BEGIN MODERATING LATE IN
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...
01/18Z CYCLE. PREVAILING VFR WITH SCT-BKN CUMULUS FIELD NOW IN
PLACE. LIGHT SE TO EAST WINDS BEGINNING TO SHIFT ONSHORE ALONG
THE COAST...AND WILL SEE THIS SHIFT REACH KPIE/KTPA IN NEXT COUPLE
OF HOURS. ISOLATED SHOWERS/STORMS ALONG THE SEA- BREEZE LATE
AFTERNOON/EARLY EVENING. BEST POTENTIAL FOR A BRIEF SHOWER BETWEEN
20-00Z FOR KPGD/KFMY/KRSW...AND ADDED VCTS TO THESE TERMINALS.
SOME POTENTIAL FOR ISOLATED STORMS TO MIGRATE CLOSER TO TAMPA BAY
TERMINALS AFTER 00Z...BUT CONFIDENCE NOT GREAT ENOUGH TO INCLUDE
IN CURRENT TAF ISSUANCE.
&&
.MARINE...
ATLANTIC HIGH PRESSURE WILL RIDGE ACROSS FLORIDA INTO
THE EASTERN GULF OF MEXICO THROUGH EARLY NEXT WEEK. THIS RIDGE
WILL SLIDE TO THE EAST AS A COLD FRONT ENTERS THE GULF AND MOVES
ACROSS THE FORECAST WATERS WEDNESDAY. WINDS SHIFT NORTH BEHIND
THIS FRONT AND MAY APPROACH ADVISORY LEVELS FOR A TIME WEDNESDAY
NIGHT INTO THURSDAY. HIGH PRESSURE THEN BUILDS OVER THE REGION BY
THE BEGINNING OF NEXT WEEKEND.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL CONTINUE TO CONTROL OUR WEATHER THROUGH THE
EARLY PORTION OF THE WEEK. NO SIGNIFICANT FIRE WEATHER CONCERNS
ARE ANTICIPATED THE NEXT COUPLE OF DAYS AS RELATIVE HUMIDITY
VALUES REMAIN GENERALLY ABOVE CRITICAL LEVELS...AND WINDS REMAIN
GENERALLY LIGHT. ALTHOUGH A FEW ISOLATED TO SCATTERED SHOWERS
ARE POSSIBLE THE NEXT FEW AFTERNOONS...THE NEXT POTENTIAL FOR
WIDESPREAD WETTING RAINS WILL NOT ARRIVE UNTIL THE PASSAGE OF
A COLD FRONT SCHEDULED TO ARRIVE DURING WEDNESDAY. A MUCH DRIER
AIRMASS ARRIVES ACROSS THE STATE FOR THE END OF THE WEEK IN THE
WAKE OF THIS FRONT.
FOG POTENTIAL...PATCHY FOG POSSIBLE EARLY MONDAY MORNING AWAY
FROM THE COAST...HOWEVER NO SIGNIFICANT AREAS OF FOG OR
VISIBILITY RESTRICTIONS ARE ANTICIPATED THROUGH TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 87 74 86 / 20 10 10 30
FMY 71 88 73 88 / 20 30 20 20
GIF 71 90 71 89 / 10 30 30 40
SRQ 72 83 72 84 / 10 10 10 20
BKV 68 88 68 87 / 20 20 20 30
SPG 74 86 75 85 / 10 10 10 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
MID TERM/LONG TERM/DECISION SUPPORT...MCKAUGHAN
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
128 PM EDT SUN MAY 1 2016
AVIATION...
01/18Z CYCLE. PREVAILING VFR WITH SCT-BKN CUMULUS FIELD NOW IN
PLACE. LIGHT SE TO EAST WINDS BEGINNING TO SHIFT ONSHORE ALONG
THE COAST...AND WILL SEE THIS SHIFT REACH KPIE/KTPA IN NEXT COUPLE
OF HOURS. ISOLATED SHOWERS/STORMS ALONG THE SEA- BREEZE LATE
AFTERNOON/EARLY EVENING. BEST POTENTIAL FOR A BRIEF SHOWER BETWEEN
20-00Z FOR KPGD/KFMY/KRSW...AND ADDED VCTS TO THESE TERMINALS.
SOME POTENTIAL FOR ISOLATED STORMS TO MIGRATE CLOSER TO TAMPA BAY
TERMINALS AFTER 00Z...BUT CONFIDENCE NOT GREAT ENOUGH TO INCLUDE
IN CURRENT TAF ISSUANCE.
&&
.PREV DISCUSSION... /ISSUED 1150 AM EDT SUN MAY 1 2016/
SYNOPSIS...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A MID/UPPER LAYER
WESTERLY FLOW PATTERN IN PLACE ACROSS THE GULF OF MEXICO AND
FLORIDA PENINSULA. SOUTHERN STREAM JET CROSSES OVER NORTHERN
MEXICO AND ACROSS THE GULF...WITH THE NOSE OF THE MAIN JETSTREAK
OVER OUR REGION. NORTHERN STREAM JET IS IN FAIRLY CLOSE PROXIMITY
TO THE NORTH...CROSSING OVER THE SOUTHERN/CENTRAL PLAINS...TO THE
MID MS AND OHIO VALLEYS. 01/12Z KTBW SOUNDING PROFILE SAMPLED
THESE WINDS ALOFT WELL...SHOWING A DEEP LAYER WEST FLOW ABOVE
700MB.
AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO
THE WEST OVER THE FLORIDA PENINSULA AND EASTERN GULF OF MEXICO. A
COMPLEX FRONTAL SYSTEM REMAINS WELL TO OUR NORTH AND NORTHWEST
FROM SOUTHERN TEXAS TO THE LOWER MS VALLEY AND NORTHEAST INTO THE
OHIO VALLEY. CLUSTERS OF SHOWERS AND STORMS ARE FORMING AND
ONGOING IN ADVANCE OF THIS FRONT...BUT WILL ALSO REMAIN WELL
REMOVED FROM OUR FORECAST AREA. THE ONLY IMPACT FROM THESE STORMS
THAT WE MAY SEE IS AN INCREASE IN HIGH CLOUDS LATER TODAY ACROSS
THE NORTHERN NATURE COAST ZONES ASSOCIATED WITH ANVIL BLOWOFF
ADVECTING DOWNSTREAM IN THE SYNOPTIC UPPER FLOW.
SHORT TERM (REST OF TODAY THROUGH MONDAY)...
BENIGN WEATHER WILL CONTINUE FOR THE NEXT SEVERAL HOURS AS
TEMPERATURES CONTINUE TO CLIMB THROUGH THE 80S...TOWARD AFTERNOON
HIGH TEMPS IN THE VICINITY OF 90 AWAY FROM THE BEACHES. THE STRONG
TERRESTRIAL HEATING WILL EVENTUALLY VEER WINDS NEAR THE COAST
ONSHORE...MAINLY AFTER 18Z. WITH THE SYNOPTIC FLOW FROM THE
SOUTHEAST...THE FLORIDA EAST COAST SEA-BREEZE WILL RACE ACROSS THE
STATE AND SET UP THE MAIN CONVERGENCE ZONE WITH THE WEST COAST
SEA-BREEZE SOMEWHERE NEAR OR JUST EAST OF THE I-75 CORRIDOR DURING
THE LATE AFTERNOON/EARLY EVENING HOURS.
LIKELY THE MOST IMPORTANT FEATURE FOR OUR FORECAST SAMPLED IN THE
KTBW SOUNDING COLUMN THIS MORNING...IS THE DEFINED
SUBSIDENCE/CAPPING INVERSION SEEN BETWEEN 700-625MB. THIS IS A
SIGNIFICANT OBSTACLE FOR PARCELS TO OVERCOME TODAY IN THE PROCESS
OF CONVECTION. ALLOWING FOR DAYTIME MIXING TO OCCUR UP TO A
SURFACE TEMP AROUND 90 STILL HAS TROUBLE OVERCOMING THIS CAP.
CERTAINLY SEEMS LIKE MANY OF THE 06Z GUIDANCE MEMBERS
UNDERESTIMATED THE STRENGTH OF THIS CAP...AND HAVE NOTICED THE
LATEST HRRR BUFR SOUNDINGS ARE HAVING A MORE DIFFICULT TIME
BREAKING THE CAP INTO FREE CONVECTION COMPARED TO EARLIER RUNS
THAT WERE NOT UTILIZING THIS REAL-TIME SOUNDING DATA.
THIS CAP WILL CERTAINLY DELAY THE ONSET OF ANY CONVECTION AS WE
WILL NEED TO REACH ABSOLUTE PEAK HEATING IF PARCELS ARE GOING TO
HAVE ANY CHANCE OF GETTING BY THIS INVERSION. LIKELY WE WILL
REQUIRE THE HIGHER DEWPOINTS WITHIN THE CONVERGENCE ZONE
ASSOCIATED WITH BOUNDARY MOISTURE POOLING TO REACH THE CAPE NEEDED
FOR STORMS. THEREFORE...STORMS SHOULD HAVE A LATE START...BE
ISOLATED TO WIDELY SCATTERED IN NATURE...AND OCCUR IN A FAIRLY
NARROW ZONE ALONG AND JUST EAST OF I-75.
TONIGHT...
WITH THE LATE START TO ANY CONVECTION...WOULD ANTICIPATE THE
CELLS THAT DO DEVELOP TO LINGERING FOR A FEW HOURS PAST SUNSET.
WILL KEEP A LOW CHANCE POP IN THE FORECAST FOR THIS FAVORED
CONVERGENCE ZONE UNTIL 03Z...AND THEN ALLOW THE REST OF THE
OVERNIGHT TO BE DRY REGION-WIDE. A FEW POCKETS OF FOG ARE QUITE
LIKELY IN THE HOURS BEFORE DAWN...BUT NEITHER THE SREF OR
STATISTICAL GUIDANCE ARE SUGGESTING WE WILL HAVE ANY SIGNIFICANT
VIS ISSUES FOR THE MORNING COMMUTE. GIVEN THAT THE COVERAGE OF
RAINFALL TODAY SHOULD BE LOW...WOULD AGREE WITH THE NWP. LOW
TEMPERATURES TONIGHT WILL BE SEASONABLY WARM WITH UPPER 60S INLAND
AND LOWER 70S ALONG THE COAST.
MONDAY...
OVERALL THE SYNOPTIC PATTERN IS NOT ALL THAT DIFFERENT FROM
TODAY. THE MOST INFLUENTIAL DIFFERENCE MAY BE THAT THE MID/UPPER
LEVEL ENVIRONMENT IS SLIGHTLY MORE MOIST AND HENCE A BIT LESS
HOSTILE TOWARD DEEP CONVECTION. ALSO...THERE DOES STILL SEEM TO BE
A HINT OF THE CAPPING INVERSION IN THE FORECAST SOUNDINGS...BUT AT
LEAST FOR NOW...IT APPEARS LESS DRAMATIC. BOTH OF THESE FACTORS
SHOULD CONTRIBUTE TO A BIT HIGHER COVERAGE OF LATE DAY STORMS
ACROSS THE SAME FAVORED CONVERGENCE ZONE RUNNING ALONG AND JUST
EAST OF THE I-75 CORRIDOR. INHERITED FORECAST HAS 30-40% POPS IN
THIS ZONE...AND THEN TAPERS RAIN CHANCES BACK TO 10-20% AT THE
COAST. BASED ON THE EARLIER MEMBERS OF THE 12Z GUIDANCE CYCLE TO
ARRIVE...DO NOT SEE MUCH REASON TO MAKE SIGNIFICANT CHANGES. WILL
WAIT FOR ALL THE 12Z CONVECTION ALLOWING GUIDANCE TO ARRIVE BEFORE
MAKING A FINAL FORECAST DECISION ON TOMORROW. ANY CONVECTION ON
MONDAY WILL AGAIN BE SUPPRESSED BY THE ENVIRONMENT ALOFT UNTIL
LATE IN THE AFTERNOON OR EARLY EVENING...WHICH SHOULD AGAIN ALLOW
LOCATIONS AWAY FROM THE IMMEDIATE COAST TO PUSH 90 FOR HIGH
TEMPERATURES. AT THE BEACHES TEMPS HOLD IN THE 80S WITH THE
DEVELOPMENT ONSHORE FLOW DURING THE AFTERNOON.
ENJOY THE REMAINDER OF YOUR SUNDAY EVERYONE!
MARINE...
ATLANTIC HIGH PRESSURE WILL RIDGE ACROSS FLORIDA INTO
THE EASTERN GULF OF MEXICO THROUGH EARLY NEXT WEEK. THIS RIDGE
WILL SLIDE TO THE EAST AS A COLD FRONT ENTERS THE GULF AND MOVES
ACROSS THE FORECAST WATERS WEDNESDAY. WINDS SHIFT NORTH BEHIND
THIS FRONT AND MAY APPROACH ADVISORY LEVELS FOR A TIME WEDNESDAY
NIGHT INTO THURSDAY. HIGH PRESSURE THEN BUILDS OVER THE REGION BY
THE BEGINNING OF NEXT WEEKEND.
$$
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 88 74 86 / 10 20 10 20
FMY 71 89 72 88 / 20 40 20 20
GIF 71 91 71 88 / 20 30 30 40
SRQ 72 85 72 83 / 10 10 10 20
BKV 68 88 67 87 / 10 20 20 30
SPG 74 86 74 85 / 10 10 10 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE...14/MROCZKA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
253 PM EDT SUN MAY 1 2016
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE THROUGH THE SHORT
TERM. CURRENTLY...THERE IS A WAVE MOVING ACROSS THE STATE
ASSOCIATED WITH THE MAIN SYSTEM BACK ACROSS MS/AL. THE HRRR HAD A
GOOD HANDLE THIS MORNING ON THE TIMING AND LOCATION OF THE EXPECTED
CONVECTION SO LEANING THAT DIRECTING IN THE SHORT TERM. THE HIGH
RES HRRR SHOWS A DIURNAL TREND WITH THESE SHOWERS AND
THUNDERSTORMS...SHOWING THEM CONTINUING THROUGH THIS EVENING ACROSS
THE AREA THEN DIMINISHING BETWEEN 03Z-06Z. WE ARE CURRENTLY UNDER A
MARGINAL RISK OF SEVERE MAINLY ACROSS NORTH GA FOR TODAY AND MONDAY.
THIS DOES LOOK GOOD AS THE BET MOISTURE AND INSTABILITY STAYS ACROSS
NORTH AND PORTIONS OF CENTRAL GA THROUGH MONDAY NIGHT/TUESDAY
MORNING. WE SHOULD SEE A VERY SIMILAR DAY MONDAY WITH WHEN AND
WHERE THE SHOWERS AND THUNDERSTORMS POP BACK UP MONDAY AFTERNOON.
HAVE CONTINUED WITH LIKELY POPS FOR MONDAY MAINLY ACROSS NORTH GA
WITH CHANCE POPS ELSEWHERE.
01
.LONG TERM /TUESDAY THROUGH SUNDAY/...
LATEST MODELS STILL IN LINE WITH THE CURRENT FORECAST. NO CHANGES
ARE PLANNED. THE PREVIOUS LONG TERM DISCUSSION FOLLOWS...
17
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
EXTENDED PERIOD STARTS OFF ON A STORMY NOTE...BUT IS OVERALL
UNEVENTFUL THROUGH THE REMAINDER OF THE WEEK. STRONG SHORTWAVE
PUSHES ACROSS THE SOUTHERN MISSISSIPPI VALLEY OVERNIGHT TUESDAY
NIGHT AND INTO GEORGIA WEDNESDAY MORNING...WITH BEST INSTABILITY
AND SHEAR AHEAD OF IT. AT THIS TIME THE ECMWF HAS BEEN MORE
AGGRESSIVE WITH THE SHORTWAVE AS IT SWEEPS THROUGH THE REGION.
EXPECT STORMS ALONG AND AHEAD OF THE SURFACE COLD FRONT TO BE
MORE ORGANIZED AND PUSH THROUGH THE STATE RATHER QUICKLY EARLY
WEDNESDAY. SEVERE STORMS CANNOT BE RULED OUT AND AT THIS TIME SPC
DOES HAVE PORTIONS OF EAST CENTRAL GEORGIA HIGHLIGHTED IN A
MARGINAL RISK FOR SEVERE STORMS. UPSTREAM CONVECTION ALONG THE
NORTHERN GULF COAST WILL STILL BE A BIG PLAYER IN THE COVERAGE AND
INTENSITY OF THE CONVECTION ACROSS THE STATE. POPS WEDNESDAY TAPER
OFF QUICKLY...THOUGH MAY BE A BIT TOO OPTIMISTIC AT THIS TIME.
CENTER OF THE UPPER TROUGH DROPS OVER THE CAROLINAS LATE IN THE
WEEK...BUT DRY/COOL NORTHWEST FLOW WILL LARGELY DOMINATE OVER THE
AREA. ASIDE FROM SOME MINIMAL WRAP AROUND MOISTURE ACROSS FAR
NORTH GEORGIA...EXPECT THE REMAINDER OF THE EXTENDED PERIOD TO BE
DRY. BREEZY CONDITIONS CAN BE EXPECTED LATE WEEK DUE TO THE TIGHT
PRESSURE GRADIENT OVER THE REGION. HIGH PRESSURE REMAINS IN PLACE
THROUGH THE WEEKEND.
31
&&
.AVIATION...
18Z UPDATE... SHOWERS AND THUNDERSTORMS POPPING ACROSS THE AREA THIS
AFTERNOON. THESE STORMS ARE EXPECTED TO CONTINUE THROUGH THIS EVENING
BEFORE DIMINISHING BY MIDNIGHT. BEST CHANCE FOR ANY OF THESE STORMS
TO AFFECT THE TAF SITES WILL BE BETWEEN 19Z-02Z. WINDS ARE EXPECTED
TO STAY OUT OF THE SW AT 10KT OR LESS. VSBYS ARE NOT EXPECTED TO GET
BELOW VFR CONDITIONS EXCEPT IN AND AROUND SHRA/TSRA. CEILINGS SHOULD
ALSO STAY ABOVE VFR LIMITS EXCEPT IN AND AROUND SHRA/TSRA ACTIVITY.
//ATL CONFIDENCE...
18Z UPDATE...
HIGH ON ALL ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 83 62 78 / 50 60 60 40
ATLANTA 66 81 62 74 / 50 60 60 40
BLAIRSVILLE 60 76 58 70 / 50 70 70 40
CARTERSVILLE 63 80 61 74 / 50 70 70 30
COLUMBUS 67 84 65 79 / 40 50 50 40
GAINESVILLE 64 79 61 73 / 50 60 60 40
MACON 65 86 64 81 / 40 50 50 50
ROME 63 80 60 74 / 40 70 70 30
PEACHTREE CITY 62 82 61 76 / 50 60 60 40
VIDALIA 68 87 68 83 / 30 50 50 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....17
AVIATION...01
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
304 PM CDT SUN MAY 1 2016
.SHORT TERM...
234 PM CDT
THROUGH MONDAY...
FOR THE REMAINDER OF THE AFTERNOON...MAIN ISSUE WILL BE TIMING OF
NEXT ROUND OF PCPN. THE MAIN UPPER LOW IS STILL WELL TO THE
WEST...OVER SRN IA/NRN MO...AND LATEST SATELLITE AND RADAR IMAGERY
INDICATE SLOWER EWD PROGRESSION THAN PREVIOUSLY ANTICIPATED.
SO...WHILE STILL FEEL THAT ANOTHER ROUND OF SHRA IS LIKELY FOR THE
REGION...IT COULD HOLD OFF FOR A COUPLE MORE HOURS. THERE ALSO
CONTINUES TO BE A SLIGHT CHANCE FOR SOME ISOLD TS OVER THE FAR
SOUTHERN PORTIONS OF THE CWA...WHERE THE ISENTROPIC LIFT JUST NORTH
OF THE SFC WARM FRONT...AND CLOSER TO THE ELEVATED BOUNDARY SHOULD
BE THE MOST CONCENTRATED. OTHERWISE...FOR THE THIS AFTERNOON AND
TONIGHT SHOULD REMAIN CLOUDY AND UNSEASONABLY COLD AS NELY FLOW
PERSISTS OFF OF THE RELATIVELY COLD LAKE MICHIGAN WATER.
TEMPERATURES TODAY SHOULD TOP OUT IN THE MIDDLE 40S NEAR THE LAKE
MICHIGAN SHORE AND REACH INTO THE LOWER 60S OVER THE FAR SOUTHERN
PORTIONS OF THE CWA. OVERNIGHT LOWS SHOULD REMAIN UNSEASONABLY
COOL...DROPPING INTO THE LOWER 40S TOWARD THE WISCONSIN BORDER AND
THE UPPER 40S SOUTH OF THE I-80 CORRIDOR.
THE MID-LEVEL SHORTWAVE SHOULD SLOWLY PROGRESS EWD OVERNIGHT TONIGHT
AND FINALLY PUSH TO THE ERN GREAT LAKES BY EARLY MORNING. WEAK
SHORT WAVE RIDGING BEHIND THE WAVE SHOULD HELP SHUT OFF AND RESIDUAL
PCPN CHANCES AND BRING SOME PARTIAL CLEARING FOR THE MORNING HOURS.
A SOUTHERN STREAM SHORTWAVE LIFTING OUT OF THE SRN PLAINS WILL BRING
ANOTHER CHANCE FOR SOME SHOWERS IN THE AFTERNOON...WITH THE HIGHEST
PCPN CHANCES SOUTH OF THE I-80 CORRIDOR. AHEAD OF THE SRN STREAM
WAVE...SOME WEAK WARM ADVECTION SHOULD ALLOW FOR SOME MODERATION OF
TEMPERATURES...THOUGH WITH WINDS STILL NELY AT THE SFC...LAKEFRONT
LOCATIONS SHOULD STILL REMAIN COOLER THAN THE REMAINDER OF THE
AREA...WITH HIGHS ALONG THE LAKEFRONT ONLY IN THE LOWER 50S...WHILE
INLAND AREAS SHOULD REACH THE UPPER 50S TO AROUND 60 DEGREES.
KREIN
&&
.LONG TERM...
203 PM CDT
MONDAY NIGHT THROUGH SUNDAY...
MONDAY NIGHT THROUGH TUESDAY...
ELONGATED MID-LVL TROUGH WILL FINALLY DEPART THE REGION LATE MON
NIGHT...HEADED FOR THE EASTERN GREAT LAKES. THIS WILL ALLOW A BROAD
SFC RIDGE TO SLIDE SOUTH FROM ONTARIO ACROSS THE WESTERN GREAT LAKES
AND ALSO STEADILY ERODE CLOUD COVER/PRECIP...HOWEVER THE FAR
SOUTHERN CWFA COULD SEE AN ISOLATED SHOWER EARLY MON EVE BEFORE
QUICKLY ENDING. WINDS WILL BE TURNING NORTHERLY BUT WITH THE WEAK
GRADIENT SPEEDS WILL NOT BE VERY HIGH...SO EXPECT THE EROSION OF
CLOUD COVER TO BE SLOW. TEMPS WILL FALL INTO THE LOW/MID 40S...BUT A
FEW AREAS IN FAR NORTHERN IL COULD DIP INTO THE UPPER 30S. THERE
DOES APPEAR TO BE ENOUGH MIXING TO PREVENT FROST FROM FORMING...SO
WILL HOLD OFF AT THIS TIME FROM INCLUDING ANY MENTION OF FROST MON
NGT.
TUE WILL BE HEAVILY INFLUENCED BY THE BROAD SFC RIDGE CENTERED OVER
THE CENTRAL ROCKIES THAT WILL EXTEND EAST THROUGH THE MID-MISSOURI
VALLEY...HOWEVER GUIDANCE IS INDICATING THAT WITH THE HIGH AMPLITUDE
MID-LVL RIDGE LIFTING INTO WESTERN CANADA A LOBE OF VORTICITY WILL
DRIVE SOUTH ACROSS LAKE SUPERIOR TUE AFTN. THIS SHORTWAVE WILL BE
ASSOCIATED WITH A DEVELOPING TROUGH THAT WILL SLIDE SOUTH OVER THE
WESTERN GREAT LAKES LATE TUE NGT...WITH MOISTURE POOLING ALONG THE
FRONTAL BOUNDARY AS IT SLIDES SOUTH LATE TUE. LAPSE RATES WILL
QUICKLY STEEPEN AS THE 850MB THERMAL GRADIENT DEVELOPS AND SFC TEMPS
TUE AFTN WILL WARM INTO THE 60S. EXPECT INSTABILITY TO REMAIN
MARGINAL...HOWEVER ENOUGH FORCING WILL BE PRESENT THAT A SLIGHT
CHANCE FOR THUNDER COULD OCCUR LATE TUE/EARLY WED. HAVE PUSHED POPS
UP TO LIKELY TUE EVE THROUGH THE OVERNIGHT HOURS.
FORTUNATELY ENSEMBLES AND OPERATIONAL SOLUTIONS CONTINUE TO BE
PROGRESSIVE AND PUSH THE HIGH AMPLITUDE RIDGE FURTHER EAST BY EARLY
WED...WHICH SHOULD HELP EJECT THE TROUGH AXIS EAST OVER LOWER
MICHIGAN WED MORNING AND BRING A RETURN TO DRY WEATHER FOR THE
FORECAST AREA BY WED EVE...WITH THE POTENTIAL THAT DRIER AIR COULD
ARRIVE BY EARLY WED AFTN. BUT WITH THE NORTHERLY FLOW TEMPS WILL
STRUGGLE TO WARM BEYOND THE 50S...AND AREAS AJACENT TO LAKE MICHIGAN
WILL REMAIN IN THE UPPER 40S WED AFTN. WED NGT ANTI-CYCLONIC FLOW
ARRIVES WITH A WEAKENING PRESSURE GRADIENT AND MUCH COLDER
TEMPS...FALLING INTO THE MID/UPR 30S. AT THIS TIME HAVE HELD OFF ON
MENTION OF FROST BUT IF CLOUDS ERODE QUICKER WED EVE THEN THE
DEVELOPMENT OF FROST IS PLAUSIBLE FOR AREAS AWAY FROM LAKE MICHIGAN
AND NORTH OF I-80.
THURSDAY THROUGH SUNDAY... LATEST ENSEMBLES CONTINUE TO BE IN GOOD
AGREEMENT WITH THE HIGH AMPLITUDE RIDGE SLIDING EAST ACROSS THE
CENTRAL PLAINS AND GREAT LAKES THURSDAY INTO FRIDAY. AS THIS FEATURE
SLIDES EAST...THE RIDGE WILL BEGIN TO WEAKEN WITH THE FOCUS TURNING
TOWARDS THE MID-LVL TROUGH PROGGED TO SLIDE INTO THE SOUTHWEST CONUS
SAT/SUN. SIMULTANEOUSLY A SHORTWAVE IS EXPECTED TO SLIDE EAST ACROSS
ONTARIO...AND COULD LAYOUT A BOUNDARY OVER THE GREAT LAKES REGION
FOR THE WEEKEND WHICH COULD BECOME A FOCAL POINT FOR
SHOWERS/THUNDERSTORMS LATER IN THE WEEKEND.
TEMPS THROUGHOUT THE EXTENDED PERIODS WILL QUICKLY MODERATE FROM THE
60S TO PERHAPS LOW 70S FRIDAY AND SATURDAY...THEN DEPENDING ON A
FRONTAL BOUNDARY PLACEMENT SUN COULD SEE TEMPS BACK IN THE 60S.
BEACHLER
&&
.AVIATION...
FOR THE 18Z TAFS...
PRIMARY CONCERNS...
-IFR CIGS THROUGH MUCH OF THE PERIOD...POSSIBLY DROPPING TO LIFR
AGAIN OVERNIGHT.
-PERIOD OF SHRA EXPECTED LATE AFTN/EVE.
CIGS REMAINING IN IFR RANGE EARLY THIS AFERNOON...WITH LIFR CIGS
PERSISTING NEAR LAKE MICHIGAN...ESPECIALLY AFFECTING KGYY. WITH
SOME WEAK MIXING AND A LITTLE DIURNAL WARMING...VIS HAS GENERALLY
IMPROVED TO VFR OR HIGHER END MVFR LEVELS ACROSS THE AREA. EXPECT
THAT CIGS WILL GRADUALLY IMPROVE THROUGH THE AFTERNOON...LIFTING
TO HIGHER END IFR OR LOWER END MVFR. HOWEVER...SINCE THE REGION
SHOULD REMAIN UNDER PERSISTENT NELY FLOW AND WELL NORTH OF A SFC
WARM FRONT EXTENDING ACROSS SRN IL/IN...DO NOT EXPECT SIGNIFICANT
IMPROVEMENT IN CONDITIONS UNTIL LATE TOMORROW WHEN THE SFC LOW
CURRENTLY OVER NRN MO FINALLY MOVES OFF TO THE EAST AND SOME DRIER
AIR CAN MOVE INTO THE REGION. UNTIL THEN...EXPECT THAT WINDS WILL
REMAIN PREVAILING NELY. CIGS/VIS SHOULD DROP AGAIN LATE THIS
AFTERNOON OR EARLY THIS EVENING AS SHRA/RA SPREADS FROM WEST TO
EAST ACROSS THE AREA AS THE SCF LOW TRACKS SLOWLY EWD. WITH THE
PCPN FALLING THROUGH THE STRATUS DECK...EXPECT THAT CIGS SHOULD
LOWER TO LIFR AGAIN OVERNIGHT TONIGHT.
KREIN
&&
.MARINE...
304 PM CDT
WINDS HAVE DIMINISHED THIS AFTERNOON TO BETWEEN 15 TO 20 KT ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN...WHICH HAS ALLOWED THE NEARSHORE
WATERS ALONG THE ILLINOIS SHORE TO DIMINSH AS WELL. STILL LOOKING AT
BETWEEN 3 TO 5 FT TO PERSIST THROUGH THIS EVENING...BUT HAVE GONE
AHEAD AND ENDED THE SMALL CRAFT ADVISORY EARLY TO ACCOUNT FOR THE
DIMINISHING TREND. WITH HIGH PRESSURE POSITIONED TO THE NORTH OVER
CENTRAL CANADA AND THE NORTHERN PLAINS....A LOW PRESSURE SYSTEM WAS
LIFTING NORTHEAST ACROSS THE OHIO VALLEY AND WILL TRY TO INCREASE
THE GRADIENT LATE TONIGHT FOR THE SOUTHERN HALF OF LAKE MICHIGAN.
ALTHOUGH THE WINDS LOOK TO REMAIN GENERALLY BETWEEN 15 TO 25 KT AT
THE MOST...BUT NOT LINGER VERY LONG. WINDS WILL THEN DIMINISH AGAIN
MONDAY AFTERNOON AS BROAD SURFACE HIGH PRESSURE CENTERED OVER THE
CENTRAL PLAINS INFLUENCES THE WESTERN GREAT LAKES WITH LIGHTER
WINDS THROUGH TUESDAY MORNING.
A FRONTAL BOUNDARY WILL THEN BEGIN TO SLIDE SOUTH FROM CENTRAL
CANADA TUESDAY AFTERNOON AS A LOW PRESSURE SYSTEM SLIDES EAST
BETWEEN JAMES BAY AND LAKE SUPERIOR. THIS FRONTAL BOUNDARY WILL
SLIDE SOUTH AND INCREASE THE GRADIENT OVER LAKE MICHIGAN AND TURN
WINDS NORTHERLY LATE TUESDAY...WHICH WILL ALLOW WAVES TO BUILD.
SMALL CRAFT HAZARDS WILL LIKELY DEVELOP ESPECIALLY FOR THE ILLINOIS
AND INDIANA NEARSHORE WEDNESDAY THROUGH THURSDAY.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
300 PM CDT SUN MAY 1 2016
.SHORT TERM...(Tonight)
ISSUED AT 300 PM CDT Sun May 1 2016
19z/2pm surface analysis shows stationary frontal boundary extending
from central Indiana southwestward into the Ozarks. Ahead of the
front, temperatures have climbed into the middle 70s and SBCAPE
values have reached the 1500-2000J/kg range south of I-70. This
will be the area of the KILX CWA that will be monitored for
potential severe weather over the next few hours as an upper low
over northern Missouri/southern Iowa shears northeastward and
provides additional synoptic lift. HRRR is showing scattered
convection across the SE CWA in the warm/unstable airmass...and
additional showers/isolated thunder further northwest in closer
proximity to the upper low between now and about 02z/9pm. Given
good convergence along the frontal boundary and strong instability,
think a strong wind/large hail threat will exist with any storms
that fire south of I-70 late this afternoon into the early evening.
Once the sun sets and daytime instability wanes, the convection will
weaken and shift eastward into the Ohio River Valley by mid-evening.
After that, mostly cloudy and cool conditions will prevail for the
balance of the night, with low temperatures ranging from the middle
40s northwest of the Illinois River...to the lower 50s far southeast.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 300 PM CDT Sun May 1 2016
The upper level trough and surface cyclonic flow is forecast to
remain in place over the Great Lakes region, effecting central and
southeast Illinois through the first part of the week. This will
keep partly sunny and chilly conditions in the area through Wed. In
addition, the cyclonic flow will provide enough focus for
instability showers periodically Mon through Wed. There could be a
break in the scattered pcpn Mon night and Tue, but still keeping a
slight chance of pcpn in the forecast. As the main upper level
system drops down toward Ohio, colder upper level temps will also
arrive, increasing the instability in the area. So have added a
slight chance for thunderstorms, along with the showers for Tue
night and Wed.
Beyond Wed, the pattern should begin to change and sfc ridging
should begin to build into the area. This will push the upper level
system to the east and bring drier weather to the area for the last
half of the weekend. As the high moves across the area, another
weather system will begin to develop in the plains and bring the
return of showers and thunderstorms for possibly next Sunday.
Temps will remain on the cool side through most of the week with the
continued cyclonic flow and general cloudiness. Once the high
pressure moves over the area, temps will begin to warm back up and
should reach into the 70s by the end of the week and into the
weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1256 PM CDT Sun May 1 2016
IFR ceilings prevail at the central Illinois terminals early this
afternoon: however, latest visible satellite imagery is showing
an appreciable thinning of the overcast. HRRR has consistently
suggested ceilings rising into the MVFR category over the next
couple of hours and have followed this trend accordingly. Think
KPIA/KBMI will be the last sites to improve as cloud cover appears
thickest in this area. With partial sunshine breaking through and
an upper low providing modest synoptic lift, think scattered
showers/thunder will develop this afternoon/evening. Have included
VCTS to cover this possibility. Once daytime instability wanes,
any showers will come to an end after sunset. After that, the low
overcast will spread/develop back southward...with the HRRR
showing IFR ceilings back at all TAF sites between 04z and 06z.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
204 PM CDT SUN MAY 1 2016
.UPDATE...1044 AM CDT
UNFORTUNATELY IT APPEARS MOTHER NATURE HAS OPTED TO HIT THE PAUSE
BUTTON...KEEPING MUCH OF NORTHERN ILLINOIS AND NORTHWEST INDIANA
STUCK IN A COOL/CLOUDY PATTERN. AS HAS BEEN THE CASE FOR THE PAST
FEW DAYS...CLOUDS WILL BLOCK MUCH OF THE SUN AGAIN TODAY AND KEEP
TEMPERATURES GENERALLY IN THE 50S ALONG AND SOUTH OF I-80. PERHAPS
A FEW SITES MAY TOUCH 60 DEGREES IN THE FAR SOUTHERN FORECAST
AREA. ELSEWHERE THE CONTINUED NORTHEAST/NORTH FLOW WILL KEEP THE
NORTHERN COUNTIES OF ILLINOIS IN THE UPPER 40S TO LOW 50S...AND
AREAS ADJACENT TO LAKE MICHIGAN WILL HAVE THE COOL MARINE AIR
KEEPING TEMPERATURES IN THE MIDDLE TO UPPER 40S.
AS THE UPPER LEVEL VORT MAX BEGINS TO LIFT NORTHEAST THIS
AFTERNOON FROM SOUTHERN IOWA/NORTHERN MISSOURI...A WEAKER SFC LOW
WILL BE SIMULTANEOUSLY LIFTING NORTHEAST ACROSS CENTRAL IL INTO
CENTRAL IN. THIS WILL HELP TO PROVIDE A MORE FORCED ENVIRONMENT
OVER THE FORECAST AREA LATER THIS AFTERNOON THAT SHOWERS WILL ONCE
AGAIN DEVELOP...WITH A SLIGHT CHANCE FOR A FEW EMBEDDED
THUNDERSTORMS MAINLY ALONG AND SOUTH OF THE KANKAKEE VALLEY.
BEACHLER
&&
.SHORT TERM...
248 AM CDT
THROUGH TONIGHT...
A CLOUDY AND DREARY DAY IS ON TAP TODAY ACROSS NORTHERN ILLINOIS
AND NORTHWEST INDIANA. AN ELONGATED AREA OF LOW PRESSURE IS
DRAPED ACROSS CENTRAL ILLINOIS AND INDIANA WITH LOW
CLOUDS...PATCHY FOG...AND DRIZZLE IN PLACE ACROSS THE LOCAL
FORECAST AREA EARLY THIS MORNING. MEANWHILE...AN UPPER LOW OVER
NEBRASKA EARLY THIS MORNING IS PROGGED TO MOVE EAST ACROSS IOWA
THIS AFTERNOON AND INTO NORTHERN ILLINOIS THIS EVENING. SCATTERED
SHOWERS ARE EXPECTED TO REDEVELOP OUT AHEAD OF THIS LOW MAINLY
DURING THE AFTERNOON AND EVENING HOURS FOR NORTHERN ILLINOIS AND
NORTHWEST INDIANA. MODELS CONTINUE TO INDICATE MODEST ELEVATED
INSTABILITY...SO CANNOT RULE OUT AN ISOLATED THUNDERSTORM MAINLY
SOUTH OF I-80 NEAR THE SURFACE FRONT...BUT THE OVERALL LIKELIHOOD
OF THUNDER IS LOW. THE UPPER LOW WILL EXIT TO OUR EAST AROUND
MIDNIGHT OR SO WITH PRECIP CHANCES QUICKLY TAPERING THEREAFTER.
BUMPED DOWN TEMPERATURES SOME FOR TODAY AND EXPECT FAIRLY SIMILAR
CONDITIONS TO YESTERDAY WITH NO REAL CHANGE IN AIRMASS. LESS
PRECIP TODAY MIGHT HELP US WARM A LITTLE MORE BUT OVERCAST SKIES
AND MORNING FOG WILL INHIBIT INSOLATION AND MODELS HAVE BEEN TOO
WARM THE LAST COUPLE OF DAYS. THE FAR SOUTHERN TIER OF COUNTIES
WOULD HAVE THE BEST CHANCE FOR BREAKING OUT OF THE LOW CLOUDS AND
SEEING A LITTLE SUNSHINE THUS EXCEEDING TEMPERATURE PROJECTIONS
BUT LEANING AGAINST THAT SCENARIO FOR NOW.
DEUBELBEISS
&&
.LONG TERM...
203 PM CDT
MONDAY NIGHT THROUGH SUNDAY...
MONDAY NIGHT THROUGH TUESDAY...
ELONGATED MID-LVL TROUGH WILL FINALLY DEPART THE REGION LATE MON
NIGHT...HEADED FOR THE EASTERN GREAT LAKES. THIS WILL ALLOW A BROAD
SFC RIDGE TO SLIDE SOUTH FROM ONTARIO ACROSS THE WESTERN GREAT LAKES
AND ALSO STEADILY ERODE CLOUD COVER/PRECIP...HOWEVER THE FAR
SOUTHERN CWFA COULD SEE AN ISOLATED SHOWER EARLY MON EVE BEFORE
QUICKLY ENDING. WINDS WILL BE TURNING NORTHERLY BUT WITH THE WEAK
GRADIENT SPEEDS WILL NOT BE VERY HIGH...SO EXPECT THE EROSION OF
CLOUD COVER TO BE SLOW. TEMPS WILL FALL INTO THE LOW/MID 40S...BUT A
FEW AREAS IN FAR NORTHERN IL COULD DIP INTO THE UPPER 30S. THERE
DOES APPEAR TO BE ENOUGH MIXING TO PREVENT FROST FROM FORMING...SO
WILL HOLD OFF AT THIS TIME FROM INCLUDING ANY MENTION OF FROST MON
NGT.
TUE WILL BE HEAVILY INFLUENCED BY THE BROAD SFC RIDGE CENTERED OVER
THE CENTRAL ROCKIES THAT WILL EXTEND EAST THROUGH THE MID-MISSOURI
VALLEY...HOWEVER GUIDANCE IS INDICATING THAT WITH THE HIGH AMPLITUDE
MID-LVL RIDGE LIFTING INTO WESTERN CANADA A LOBE OF VORTICITY WILL
DRIVE SOUTH ACROSS LAKE SUPERIOR TUE AFTN. THIS SHORTWAVE WILL BE
ASSOCIATED WITH A DEVELOPING TROUGH THAT WILL SLIDE SOUTH OVER THE
WESTERN GREAT LAKES LATE TUE NGT...WITH MOISTURE POOLING ALONG THE
FRONTAL BOUNDARY AS IT SLIDES SOUTH LATE TUE. LAPSE RATES WILL
QUICKLY STEEPEN AS THE 850MB THERMAL GRADIENT DEVELOPS AND SFC TEMPS
TUE AFTN WILL WARM INTO THE 60S. EXPECT INSTABILITY TO REMAIN
MARGINAL...HOWEVER ENOUGH FORCING WILL BE PRESENT THAT A SLIGHT
CHANCE FOR THUNDER COULD OCCUR LATE TUE/EARLY WED. HAVE PUSHED POPS
UP TO LIKELY TUE EVE THROUGH THE OVERNIGHT HOURS.
FORTUNATELY ENSEMBLES AND OPERATIONAL SOLUTIONS CONTINUE TO BE
PROGRESSIVE AND PUSH THE HIGH AMPLITUDE RIDGE FURTHER EAST BY EARLY
WED...WHICH SHOULD HELP EJECT THE TROUGH AXIS EAST OVER LOWER
MICHIGAN WED MORNING AND BRING A RETURN TO DRY WEATHER FOR THE
FORECAST AREA BY WED EVE...WITH THE POTENTIAL THAT DRIER AIR COULD
ARRIVE BY EARLY WED AFTN. BUT WITH THE NORTHERLY FLOW TEMPS WILL
STRUGGLE TO WARM BEYOND THE 50S...AND AREAS AJACENT TO LAKE MICHIGAN
WILL REMAIN IN THE UPPER 40S WED AFTN. WED NGT ANTI-CYCLONIC FLOW
ARRIVES WITH A WEAKENING PRESSURE GRADIENT AND MUCH COLDER
TEMPS...FALLING INTO THE MID/UPR 30S. AT THIS TIME HAVE HELD OFF ON
MENTION OF FROST BUT IF CLOUDS ERODE QUICKER WED EVE THEN THE
DEVELOPMENT OF FROST IS PLAUSIBLE FOR AREAS AWAY FROM LAKE MICHIGAN
AND NORTH OF I-80.
THURSDAY THROUGH SUNDAY... LATEST ENSEMBLES CONTINUE TO BE IN GOOD
AGREEMENT WITH THE HIGH AMPLITUDE RIDGE SLIDING EAST ACROSS THE
CENTRAL PLAINS AND GREAT LAKES THURSDAY INTO FRIDAY. AS THIS FEATURE
SLIDES EAST...THE RIDGE WILL BEGIN TO WEAKEN WITH THE FOCUS TURNING
TOWARDS THE MID-LVL TROUGH PROGGED TO SLIDE INTO THE SOUTHWEST CONUS
SAT/SUN. SIMULTANEOUSLY A SHORTWAVE IS EXPECTED TO SLIDE EAST ACROSS
ONTARIO...AND COULD LAYOUT A BOUNDARY OVER THE GREAT LAKES REGION
FOR THE WEEKEND WHICH COULD BECOME A FOCAL POINT FOR
SHOWERS/THUNDERSTORMS LATER IN THE WEEKEND.
TEMPS THROUGHOUT THE EXTENDED PERIODS WILL QUICKLY MODERATE FROM THE
60S TO PERHAPS LOW 70S FRIDAY AND SATURDAY...THEN DEPENDING ON A
FRONTAL BOUNDARY PLACEMENT SUN COULD SEE TEMPS BACK IN THE 60S.
BEACHLER
&&
.AVIATION...
FOR THE 18Z TAFS...
PRIMARY CONCERNS...
-IFR CIGS THROUGH MUCH OF THE PERIOD...POSSIBLY DROPPING TO LIFR
AGAIN OVERNIGHT.
-PERIOD OF SHRA EXPECTED LATE AFTN/EVE.
CIGS REMAINING IN IFR RANGE EARLY THIS AFERNOON...WITH LIFR CIGS
PERSISTING NEAR LAKE MICHIGAN...ESPECIALLY AFFECTING KGYY. WITH
SOME WEAK MIXING AND A LITTLE DIURNAL WARMING...VIS HAS GENERALLY
IMPROVED TO VFR OR HIGHER END MVFR LEVELS ACROSS THE AREA. EXPECT
THAT CIGS WILL GRADUALLY IMPROVE THROUGH THE AFTERNOON...LIFTING
TO HIGHER END IFR OR LOWER END MVFR. HOWEVER...SINCE THE REGION
SHOULD REMAIN UNDER PERSISTENT NELY FLOW AND WELL NORTH OF A SFC
WARM FRONT EXTENDING ACROSS SRN IL/IN...DO NOT EXPECT SIGNIFICANT
IMPROVEMENT IN CONDITIONS UNTIL LATE TOMORROW WHEN THE SFC LOW
CURRENTLY OVER NRN MO FINALLY MOVES OFF TO THE EAST AND SOME DRIER
AIR CAN MOVE INTO THE REGION. UNTIL THEN...EXPECT THAT WINDS WILL
REMAIN PREVAILING NELY. CIGS/VIS SHOULD DROP AGAIN LATE THIS
AFTERNOON OR EARLY THIS EVENING AS SHRA/RA SPREADS FROM WEST TO
EAST ACROSS THE AREA AS THE SCF LOW TRACKS SLOWLY EWD. WITH THE
PCPN FALLING THROUGH THE STRATUS DECK...EXPECT THAT CIGS SHOULD
LOWER TO LIFR AGAIN OVERNIGHT TONIGHT.
KREIN
&&
.MARINE...
253 AM CDT
A PERIOD OF MODERATELY STRONG NORTHEAST WINDS GUSTING 20-25 KT
WILL PERSIST ACROSS LAKE MICHIGAN TODAY...EVENTUALLY BACKING MORE
NORTHERLY AND DIMINISHING AS LOW PRESSURE MOVES EAST ACROSS
ILLINOIS AND INDIANA AND REACHES THE UPPER OHIO VALLEY EARLY
MONDAY. WEAK HIGH PRESSURE RIDGING WILL THEN SETTLE SOUTH ACROSS
THE GREAT LAKES REGION MONDAY AND MONDAY EVENING...BEFORE AN AREA
OF LOW PRESSURE APPROACHES FROM ONTARIO. THIS LOW...AND ITS
ACCOMPANYING COLD FRONTAL TROUGH... WILL PUSH SOUTHEAST ACROSS
THE LAKE TUESDAY AND TUESDAY NIGHT. LIGHT WINDS WILL SHIFT TO THE
SOUTHWEST AND INCREASE TO 15-25 KTS INITIALLY AS THE TROUGH AND
LOW APPROACH TUESDAY...SHIFTING NORTH-NORTHWEST BEHIND THE FRONT
EARLY WEDNESDAY WITH SPEEDS 25-30 KT AND PERSISTING INTO THURSDAY
BEFORE DIMINISHING THURSDAY NIGHT/EARLY FRIDAY AS HIGH PRESSURE
RIDGING BUILDS IN FROM THE NORTHWEST. ON THE SOUTH END OF THE
LAKE...MARGINAL SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH THE DAY. WILL MONITOR AS WE MAY BE ABLE TO CANCEL
EARLIER THAN CURRENT EXPIRATION THROUGH THIS EVENING.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 AM
MONDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1256 PM CDT SUN MAY 1 2016
.UPDATE...
Issued at 1102 AM CDT Sun May 1 2016
Made some updates to the forecast earlier this morning to drop
PoPs across the board during the morning and to go with mostly
sunny skies south of I-70. Latest visible satellite imagery
continues to show overcast conditions across much of the KILX CWA,
with areas south of I-70 still seeing plenty of sunshine. As a
result, a strong temperature gradient has developed across the
area...with readings ranging from the upper 40s far north around
Lacon to close to 70 degrees far southeast. HRRR suggests the
clouds will gradually thin this afternoon, but think this might be
too optimistic based on prevailing northeast flow north of frontal
boundary in the Ohio River Valley. As a result, will continue with
a mostly cloudy forecast across much of the area. As an upper low
currently over southern Iowa shears northeastward, scattered
showers and a few thunderstorms will develop during the afternoon.
Think the best areal coverage of precip will remain focused
across the central and northern CWA, where high chance PoPs are
warranted. PoPs will decrease further southeast away from the
stronger forcing. Severe threat will remain minimal today, as
best forcing and strongest instability will not coincide anywhere
across the CWA. Afternoon high temperatures will range from the
lower 50s north of Peoria, to the lower to middle 70s south of
I-70.
&&
.SHORT TERM...(Today)
ISSUED AT 305 AM CDT Sun May 1 2016
A rather complex forecast exists across central and southeast
Illinois today, with many factors to consider. A nearly stationary
surface front cuts across the forecast area generally a little south
of, and nearly parallel to, the I-72 corridor. To the south of the
boundary, partly cloudy skies exist, with scattered convection to
the south of I-70. To the north of the boundary, extensive
fog/stratus exists, with visibilities significantly reduced in some
areas. The fog is most dense near the edge of the stratus, and
surface obs suggest a Dense Fog Advisory should be considered.
However, the cloud edge is slowly sinking to the south and this
would suggest that dense fog will not remain in any one location for
a significant period of time. Plan to hold off on Dense Fog Advisory
for now with this in mind, but will continue to monitor visibility
trends closely through sunrise.
Other main concern is the expected precipitation coverage today. A
broad northeast to southwest oriented upper-level trof stretches
across the lower 48 states, with several smaller scale upper lows
embedded within it. The feature we need to key in on today is the
upper low spinning over the central Plains. This feature is expected
to shear northeast into the Great Lakes region today. The forcing
associated with this weakening feature, and associated wave on the
surface front, will be our primary precipitation trigger. There is
currently very little on radar upstream, and expect the bulk of our
precipitation will occur through a combination of diurnal heating
and mid-level cooling with the approach of the upper low remnants.
This thinking supports scattered showers across the area by
afternoon, with a few thunderstorms also possible. The thunderstorms
should mostly occur along/south of the surface front. A few of the
storms along/south of I-70 may be strong given the modest
instability (CAPEs from 1000-2000 j/kg) and shear profiles (bulk
shear to 45 kts) anticipated by afternoon.
A significant N-S temperatures gradient is likely across the area
today with the surface front in the area. Daytime highs should range
from the mid 50s NW around Galesburg to mid 70s SE around
Lawrenceville.
.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT Sun May 1 2016
Persistent upper troughing pattern expected over the eastern U.S.
much of the upcoming week, as a significant ridge builds west of the
Rockies. This will send lobes of cooler air southward into the Great
Lakes region, with 850 mb temperatures over our area dipping to
around zero Celsius on Tuesday, and Wednesday night through
Thursday. This should result in highs several degrees below normal
for early May. Late in the week, an omega blocking pattern will
evolve, although the latest runs of the ECMWF and GFS do show the
ridge edging eastward, bringing a significant warming trend for next
weekend.
Remnants of current upper low over Nebraska will drift eastward
early this week, and stretch out into a trough which will drop
toward the Ohio Valley on Tuesday. With these features around, it
will be difficult to eliminate mention of PoP`s. Have increased rain
chances to around 30% on Monday over the southeast CWA and went with
slight chances as far north as Bloomington and Havana, with the
threat diminishing with loss of daytime heating. With the trough
further south on Tuesday, slight chance PoP`s were kept over the
areas south of I-70. A more significant rain chance is expected late
Tuesday night into Wednesday, as a large upper low drops southward
into the Great Lakes. Have increased PoP`s to around 35-40% over the
eastern CWA on Wednesday. Rather significant cold pocket at 500 mb
will accompany this low, and would not be surprised to see some
isolated thunder. However, the coldest part of this will be tracking
into Indiana, so will hold off on any thunder mention for now. Dry
weather is expected late in the week, as high pressure dominates the
Mississippi Valley as the upper ridge arrives.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1256 PM CDT Sun May 1 2016
IFR ceilings prevail at the central Illinois terminals early this
afternoon: however, latest visible satellite imagery is showing
an appreciable thinning of the overcast. HRRR has consistently
suggested ceilings rising into the MVFR category over the next
couple of hours and have followed this trend accordingly. Think
KPIA/KBMI will be the last sites to improve as cloud cover appears
thickest in this area. With partial sunshine breaking through and
an upper low providing modest synoptic lift, think scattered
showers/thunder will develop this afternoon/evening. Have included
VCTS to cover this possibility. Once daytime instability wanes,
any showers will come to an end after sunset. After that, the low
overcast will spread/develop back southward...with the HRRR
showing IFR ceilings back at all TAF sites between 04z and 06z.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...BAK
LONG TERM...Geelhart
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE, IL
1244 PM CDT SUN MAY 1 2016
.UPDATE...
1044 AM CDT
UNFORTUNATELY IT APPEARS MOTHER NATURE HAS OPTED TO HIT THE PAUSE
BUTTON...KEEPING MUCH OF NORTHERN ILLINOIS AND NORTHWEST INDIANA
STUCK IN A COOL/CLOUDY PATTERN. AS HAS BEEN THE CASE FOR THE PAST
FEW DAYS...CLOUDS WILL BLOCK MUCH OF THE SUN AGAIN TODAY AND KEEP
TEMPERATURES GENERALLY IN THE 50S ALONG AND SOUTH OF I-80. PERHAPS
A FEW SITES MAY TOUCH 60 DEGREES IN THE FAR SOUTHERN FORECAST
AREA. ELSEWHERE THE CONTINUED NORTHEAST/NORTH FLOW WILL KEEP THE
NORTHERN COUNTIES OF ILLINOIS IN THE UPPER 40S TO LOW 50S...AND
AREAS ADJACENT TO LAKE MICHIGAN WILL HAVE THE COOL MARINE AIR
KEEPING TEMPERATURES IN THE MIDDLE TO UPPER 40S.
AS THE UPPER LEVEL VORT MAX BEGINS TO LIFT NORTHEAST THIS
AFTERNOON FROM SOUTHERN IOWA/NORTHERN MISSOURI...A WEAKER SFC LOW
WILL BE SIMULTANEOUSLY LIFTING NORTHEAST ACROSS CENTRAL IL INTO
CENTRAL IN. THIS WILL HELP TO PROVIDE A MORE FORCED ENVIRONMENT
OVER THE FORECAST AREA LATER THIS AFTERNOON THAT SHOWERS WILL ONCE
AGAIN DEVELOP...WITH A SLIGHT CHANCE FOR A FEW EMBEDDED
THUNDERSTORMS MAINLY ALONG AND SOUTH OF THE KANKAKEE VALLEY.
BEACHLER
&&
.SHORT TERM...
248 AM CDT
THROUGH TONIGHT...
A CLOUDY AND DREARY DAY IS ON TAP TODAY ACROSS NORTHERN ILLINOIS
AND NORTHWEST INDIANA. AN ELONGATED AREA OF LOW PRESSURE IS
DRAPED ACROSS CENTRAL ILLINOIS AND INDIANA WITH LOW
CLOUDS...PATCHY FOG...AND DRIZZLE IN PLACE ACROSS THE LOCAL
FORECAST AREA EARLY THIS MORNING. MEANWHILE...AN UPPER LOW OVER
NEBRASKA EARLY THIS MORNING IS PROGGED TO MOVE EAST ACROSS IOWA
THIS AFTERNOON AND INTO NORTHERN ILLINOIS THIS EVENING. SCATTERED
SHOWERS ARE EXPECTED TO REDEVELOP OUT AHEAD OF THIS LOW MAINLY
DURING THE AFTERNOON AND EVENING HOURS FOR NORTHERN ILLINOIS AND
NORTHWEST INDIANA. MODELS CONTINUE TO INDICATE MODEST ELEVATED
INSTABILITY...SO CANNOT RULE OUT AN ISOLATED THUNDERSTORM MAINLY
SOUTH OF I-80 NEAR THE SURFACE FRONT...BUT THE OVERALL LIKELIHOOD
OF THUNDER IS LOW. THE UPPER LOW WILL EXIT TO OUR EAST AROUND
MIDNIGHT OR SO WITH PRECIP CHANCES QUICKLY TAPERING THEREAFTER.
BUMPED DOWN TEMPERATURES SOME FOR TODAY AND EXPECT FAIRLY SIMILAR
CONDITIONS TO YESTERDAY WITH NO REAL CHANGE IN AIRMASS. LESS
PRECIP TODAY MIGHT HELP US WARM A LITTLE MORE BUT OVERCAST SKIES
AND MORNING FOG WILL INHIBIT INSOLATION AND MODELS HAVE BEEN TOO
WARM THE LAST COUPLE OF DAYS. THE FAR SOUTHERN TIER OF COUNTIES
WOULD HAVE THE BEST CHANCE FOR BREAKING OUT OF THE LOW CLOUDS AND
SEEING A LITTLE SUNSHINE THUS EXCEEDING TEMPERATURE PROJECTIONS
BUT LEANING AGAINST THAT SCENARIO FOR NOW.
DEUBELBEISS
&&
.LONG TERM...
248 AM CDT
MONDAY THROUGH SATURDAY...
STRONG BLOCKING RIDGE WILL BE IN PLACE ACROSS MUCH OF THE WESTERN
HALF OF THE CONTINENT TO START NEXT WEEK...WHILE A DEEP TROUGH
CONTINUES ACROSS THE MIDWEST AND GREAT LAKES. SOUTHERN STREAM
SHORT WAVES WILL BRING A SLIGHT CHANCE FOR A FEW LIGHT SHOWERS OR
SPRINKLES SOUTH OF I-80 ON MONDAY...FAVORED DIURNALLY IN THE
AFTERNOON AND EARLY EVENING. FORECAST SOUNDINGS SHOW AN
INVERSION/ISOTHERMAL LAYER BASED AROUND 800 MB MONDAY SO THERE
ISNT MUCH OPPORTUNITY FOR DEEP CONVECTIVE GROWTH...AND SUSPECT GFS
IS OVERPRODUCING QPF. WILL MAINTAIN 20 POPS FOR THE FAR SOUTHERN
FORECAST AREA. EXPECT HIGH TEMPS AROUND 60.
ON TUESDAY...WILL SEE A LITTLE MORE SUNSHINE AS TRANSIENT MID
LEVEL RIDGING PUSHES ACROSS THE AREA. FORECAST SOUNDINGS TUESDAY
INDICATE STEEP LOW/MID LEVEL LAPSE RATES DEVELOPING DURING THE
AFTERNOON WHICH SHOULD SUPPORT AT LEAST SOME DIURNAL CU
GROWTH...THOUGH WITH NO SIGNIFICANT FORCING OVER THE AREA WILL NOT
MENTION ANY POPS AT THIS TIME EVEN THOUGH THERMODYNAMICALLY
TUESDAY LOOKS BETTER FOR PRODUCING PRECIP THAN MONDAY. MODELS ARE
BACKING OFF ON TEMPERATURES TUESDAY AFTERNOON...DESPITE DEEP
MIXING STILL EXPECTED. TEMPS ALOFT NOW APPEAR TO ONLY SUPPORT LOW
TO MID 60S SO HAVE TRIMMED BACK TEMPS A FEW DEGREES.
TUESDAY NIGHT INTO WEDNESDAY WILL BRING MORE UNSETTLED AND COOLER
CONDITIONS BACK TO THE REGION. GUIDANCE CONTINUES TO INDICATE A
WAVE TOPPING THE STRONG WEST COAST RIDGE NEAR THE ARCTIC CIRCLE
EARLY IN THE WEEK WILL DISLODGE A COLD AIRMASS SET TO ARRIVE INTO
PORTIONS OF THE GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. GFS
CONTINUES TO RUN SLIGHTLY COOLER THAN THE ECMWF THOUGH BOTH MODELS
WOULD SUPPORT HIGHS ONLY IN THE LOW TO MID 50S WEDNESDAY AND
THURSDAY...WITH TEMPS NEAR THE LAKE ONLY IN THE 40S. WILL CONTINUE
TO NUDGE DOWNWARD FROM THE STARTING POINT OF OUR GENERAL MODEL
CONSENSUS BLEND WHICH STILL APPEARS TOO WARM...HOWEVER ANTICIPATE
FURTHER DOWNWARD REVISIONS TO TEMPS IF TRENDS OVER THE PAST COUPLE
DAYS HOLD. THERE REMAIN SOME MODEST TIMING AND TRACK
DIFFERENCES...BUT SHOWERS ARE POSSIBLE WITH THE COLD FRONT AND
ADDITIONAL SHOWERS ARE POSSIBLE WEDNESDAY AFTERNOON/EVENING AS
DIURNAL INSTABILITY DEVELOPS ONCE AGAIN.
FOR THOSE HOPING FOR MORE SUMMER-LIKE CONDITIONS TO RETURN...
GUIDANCE CONTINUES TO INDICATE THE WEST COAST RIDGE WILL INCH
EASTWARD THROUGH THE WEEK...AND SHOULD BEGIN TO EXERT ITS
INFLUENCE OVER THE WESTERN GREAT LAKES REGION BY LATE IN THE
WEEK AND INTO NEXT WEEKEND. THIS WILL BRING A WARMING TREND FRIDAY
AND SATURDAY ALONG WITH DRY CONDITIONS AND PLENTY OF SUNSHINE. IF
ECMWF/GFS PROJECTIONS HOLD...WE WILL BE WARMING WELL INTO THE 70S
SATURDAY POSSIBLY PUSHING THE 80 MARK IN SOME AREAS.
DEUBELBEISS
&&
.AVIATION...
FOR THE 18Z TAFS...
PRIMARY CONCERNS...
-IFR CIGS THROUGH MUCH OF THE PERIOD...POSSIBLY DROPPING TO LIFR
AGAIN OVERNIGHT.
-PERIOD OF SHRA EXPECTED LATE AFTN/EVE.
CIGS REMAINING IN IFR RANGE EARLY THIS AFERNOON...WITH LIFR CIGS
PERSISTING NEAR LAKE MICHIGAN...ESPECIALLY AFFECTING KGYY. WITH
SOME WEAK MIXING AND A LITTLE DIURNAL WARMING...VIS HAS GENERALLY
IMPROVED TO VFR OR HIGHER END MVFR LEVELS ACROSS THE AREA. EXPECT
THAT CIGS WILL GRADUALLY IMPROVE THROUGH THE AFTERNOON...LIFTING
TO HIGHER END IFR OR LOWER END MVFR. HOWEVER...SINCE THE REGION
SHOULD REMAIN UNDER PERSISTENT NELY FLOW AND WELL NORTH OF A SFC
WARM FRONT EXTENDING ACROSS SRN IL/IN...DO NOT EXPECT SIGNIFICANT
IMPROVEMENT IN CONDITIONS UNTIL LATE TOMORROW WHEN THE SFC LOW
CURRENTLY OVER NRN MO FINALLY MOVES OFF TO THE EAST AND SOME DRIER
AIR CAN MOVE INTO THE REGION. UNTIL THEN...EXPECT THAT WINDS WILL
REMAIN PREVAILING NELY. CIGS/VIS SHOULD DROP AGAIN LATE THIS
AFTERNOON OR EARLY THIS EVENING AS SHRA/RA SPREADS FROM WEST TO
EAST ACROSS THE AREA AS THE SCF LOW TRACKS SLOWLY EWD. WITH THE
PCPN FALLING THROUGH THE STRATUS DECK...EXPECT THAT CIGS SHOULD
LOWER TO LIFR AGAIN OVERNIGHT TONIGHT.
KREIN
&&
.MARINE...
253 AM CDT
A PERIOD OF MODERATELY STRONG NORTHEAST WINDS GUSTING 20-25 KT
WILL PERSIST ACROSS LAKE MICHIGAN TODAY...EVENTUALLY BACKING MORE
NORTHERLY AND DIMINISHING AS LOW PRESSURE MOVES EAST ACROSS
ILLINOIS AND INDIANA AND REACHES THE UPPER OHIO VALLEY EARLY
MONDAY. WEAK HIGH PRESSURE RIDGING WILL THEN SETTLE SOUTH ACROSS
THE GREAT LAKES REGION MONDAY AND MONDAY EVENING...BEFORE AN AREA
OF LOW PRESSURE APPROACHES FROM ONTARIO. THIS LOW...AND ITS
ACCOMPANYING COLD FRONTAL TROUGH... WILL PUSH SOUTHEAST ACROSS
THE LAKE TUESDAY AND TUESDAY NIGHT. LIGHT WINDS WILL SHIFT TO THE
SOUTHWEST AND INCREASE TO 15-25 KTS INITIALLY AS THE TROUGH AND
LOW APPROACH TUESDAY...SHIFTING NORTH-NORTHWEST BEHIND THE FRONT
EARLY WEDNESDAY WITH SPEEDS 25-30 KT AND PERSISTING INTO THURSDAY
BEFORE DIMINISHING THURSDAY NIGHT/EARLY FRIDAY AS HIGH PRESSURE
RIDGING BUILDS IN FROM THE NORTHWEST. ON THE SOUTH END OF THE
LAKE...MARGINAL SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH THE DAY. WILL MONITOR AS WE MAY BE ABLE TO CANCEL
EARLIER THAN CURRENT EXPIRATION THROUGH THIS EVENING.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 AM
MONDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1102 AM CDT SUN MAY 1 2016
.UPDATE...
Issued at 1102 AM CDT Sun May 1 2016
Made some updates to the forecast earlier this morning to drop
PoPs across the board during the morning and to go with mostly
sunny skies south of I-70. Latest visible satellite imagery
continues to show overcast conditions across much of the KILX CWA,
with areas south of I-70 still seeing plenty of sunshine. As a
result, a strong temperature gradient has developed across the
area...with readings ranging from the upper 40s far north around
Lacon to close to 70 degrees far southeast. HRRR suggests the
clouds will gradually thin this afternoon, but think this might be
too optimistic based on prevailing northeast flow north of frontal
boundary in the Ohio River Valley. As a result, will continue with
a mostly cloudy forecast across much of the area. As an upper low
currently over southern Iowa shears northeastward, scattered
showers and a few thunderstorms will develop during the afternoon.
Think the best areal coverage of precip will remain focused
across the central and northern CWA, where high chance PoPs are
warranted. PoPs will decrease further southeast away from the
stronger forcing. Severe threat will remain minimal today, as
best forcing and strongest instability will not coincide anywhere
across the CWA. Afternoon high temperatures will range from the
lower 50s north of Peoria, to the lower to middle 70s south of
I-70.
&&
.SHORT TERM...(Today)
ISSUED AT 305 AM CDT Sun May 1 2016
A rather complex forecast exists across central and southeast
Illinois today, with many factors to consider. A nearly stationary
surface front cuts across the forecast area generally a little south
of, and nearly parallel to, the I-72 corridor. To the south of the
boundary, partly cloudy skies exist, with scattered convection to
the south of I-70. To the north of the boundary, extensive
fog/stratus exists, with visibilities significantly reduced in some
areas. The fog is most dense near the edge of the stratus, and
surface obs suggest a Dense Fog Advisory should be considered.
However, the cloud edge is slowly sinking to the south and this
would suggest that dense fog will not remain in any one location for
a significant period of time. Plan to hold off on Dense Fog Advisory
for now with this in mind, but will continue to monitor visibility
trends closely through sunrise.
Other main concern is the expected precipitation coverage today. A
broad northeast to southwest oriented upper-level trof stretches
across the lower 48 states, with several smaller scale upper lows
embedded within it. The feature we need to key in on today is the
upper low spinning over the central Plains. This feature is expected
to shear northeast into the Great Lakes region today. The forcing
associated with this weakening feature, and associated wave on the
surface front, will be our primary precipitation trigger. There is
currently very little on radar upstream, and expect the bulk of our
precipitation will occur through a combination of diurnal heating
and mid-level cooling with the approach of the upper low remnants.
This thinking supports scattered showers across the area by
afternoon, with a few thunderstorms also possible. The thunderstorms
should mostly occur along/south of the surface front. A few of the
storms along/south of I-70 may be strong given the modest
instability (CAPEs from 1000-2000 j/kg) and shear profiles (bulk
shear to 45 kts) anticipated by afternoon.
A significant N-S temperatures gradient is likely across the area
today with the surface front in the area. Daytime highs should range
from the mid 50s NW around Galesburg to mid 70s SE around
Lawrenceville.
.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT Sun May 1 2016
Persistent upper troughing pattern expected over the eastern U.S.
much of the upcoming week, as a significant ridge builds west of the
Rockies. This will send lobes of cooler air southward into the Great
Lakes region, with 850 mb temperatures over our area dipping to
around zero Celsius on Tuesday, and Wednesday night through
Thursday. This should result in highs several degrees below normal
for early May. Late in the week, an omega blocking pattern will
evolve, although the latest runs of the ECMWF and GFS do show the
ridge edging eastward, bringing a significant warming trend for next
weekend.
Remnants of current upper low over Nebraska will drift eastward
early this week, and stretch out into a trough which will drop
toward the Ohio Valley on Tuesday. With these features around, it
will be difficult to eliminate mention of PoP`s. Have increased rain
chances to around 30% on Monday over the southeast CWA and went with
slight chances as far north as Bloomington and Havana, with the
threat diminishing with loss of daytime heating. With the trough
further south on Tuesday, slight chance PoP`s were kept over the
areas south of I-70. A more significant rain chance is expected late
Tuesday night into Wednesday, as a large upper low drops southward
into the Great Lakes. Have increased PoP`s to around 35-40% over the
eastern CWA on Wednesday. Rather significant cold pocket at 500 mb
will accompany this low, and would not be surprised to see some
isolated thunder. However, the coldest part of this will be tracking
into Indiana, so will hold off on any thunder mention for now. Dry
weather is expected late in the week, as high pressure dominates the
Mississippi Valley as the upper ridge arrives.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 654 AM CDT Sun May 1 2016
IFR or lower aviation weather conditions expected through the
bulk of the 12Z TAF valid time. Some improvement to MVFR is
possible at KSPI, KDEC, and KCMI this afternoon through diurnal
mixing, but IFR conditions should quickly return tonight. While
the coverage is not expected to be great, scattered showers/storms
are likely this afternoon as an upper level disturbance passes
through the area and diurnal heating is maximized.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...BAK
LONG TERM...Geelhart
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 PM EDT SUN MAY 1 2016
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 409 PM EDT SUN MAY 1 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A REX BLOCK OVER WRN NOAM
RESULTING IN WEAK NW FLOW INTO THE NRN LAKES. AT THE SFC...A RIDGE
EXTENDED FROM JAMES BAY INTO WRN LAKE SUPERIOR BRINGING N TO NE
WINDS INTO MOST OF UPPER MI. HOWEVER...THE GRADIENT WAS WEAK ENOUGH
TO ALLOW LAKE BREEZE DEVELOPMENT OFF OF LAKE MICHIGAN. VIS LOOP
SHOWED CU OVER THE INLAND WEST AND LOW LEVEL CONVERGENCE AREA IN
THE E HALF.
TONIGHT...HIGH PRESSURE BUILDING INTO UPPER MI WILL BRING MOSTLY
CLEAR SKIES AND LIGHT WINDS TONIGHT. FAVORABLE RADIATIONAL COOLING
CONDITIONS WILL ALLOW TEMPS TO DROP INTO THE UPPER 20S INLAND WEST
AND TO THE LOWER TO MID 30S OVER THE REST OF THE CWA.
MONDAY...DRY CONDITIONS WILL CONTINUE WITH SFC RIDGING ACROSS THE
AREA AND THE ACTIVE WEATHER ASSOCIATED WITH A MID LEVEL SHRTWV
REMAINING WELL TO THE SE OVER THE ERN LAKES. A WEAK GRADIENT WILL
AGAIN ALLOW PROMINENT LAKE BREEZE DEVELOPMENT WITH THE LAKE SUPERIOR
BREEZE REACHING THE FARTHEST INLAND. SUNSHINE AND DEEP MIXING WILL
RESULT IN TEMPS INTO THE LOW TO MI 60S INLAND WEST WITH 50S NEAR THE
GREAT LAKES ALONG WITH CU DEVELPMENT SIMILAR TO TODAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 429 PM EDT SUN MAY 1 2016
THROUGH THE WEEK...RIDGING/POSITIVE HEIGHT ANOMALIES OF VARYING
AMPLITUDE WILL PREVAIL ACROSS ROUGHLY THE W HALF OF CANADA WITH
HEIGHT ANOMALIES PEAKING OVER THE NEXT COUPLE OF DAYS. THIS WILL IN
TURN FAVOR TROFFING OVER ERN N AMERICA WITH THE TROF REACHING PEAK
AMPLITUDE DURING THE MIDDLE OF THE WEEK. MEANWHILE...ENERGY
APPROACHING THE W COAST WILL SPLIT...RESULTING IN DEVELOPMENT OF
ANOTHER SW CONUS CLOSED MID LEVEL LOW LATER THIS WEEK. THIS PATTERN
FAVORS BLO NORMAL PCPN FOR THE UPPER LAKES. DOWNSTREAM OF THE
PEAKING WRN CANADA RIDGE...STRONGER SHORTWAVE ENERGY WILL BE FORCED
TO DROP FARTHER S INTO THE GREAT LAKES REGION TUE/WED WITH COLD
FROPA OCCURRING TUE AFTN/EVENING. THIS FROPA BRINGS THE BEST CHC OF
PCPN THIS WEEK. WITH DECENT FORCING...POPS AT LEAST INTO THE HIGH
CHC TO LOW LIKELY CATEGORY APPEAR REASONABLE FOR TUE AFTN/EVENING.
DECENT FORCING/STEEP MIDLEVEL LAPSE RATES AROUND 7C/KM AND A LITTLE
INSTABILITY WITH FAVORABLE TIME OF DAY SUGGEST THERE COULD BE A FEW
RUMBLES OF THUNDER. DEPENDING ON HOW AMPLIFIED THE MID LEVEL TROF
BECOMES...SOME LIGHT PCPN MAY LINGER INTO WED. MEDIUM RANGE MODEL
RUNS YESTERDAY TRENDED TOWARD MID LEVEL LOW DEVELOPMENT CLOSE ENOUGH
TO UPPER MI TO RESULT IN SOME LIGHT PCPN ON WED. SINCE THEN...
GUIDANCE HAS WAIVERED ON THIS IDEA. WILL LARGELY MAINTAIN CONTINUITY
WITH PREVIOUS FCST IN SHOWING SCHC POPS (CHC ACROSS THE NCNTRL AND
E) INTO WED MORNING. IF THERE IS ANY PCPN...MAY SEE A RAIN/SNOW MIX
LATE TUE NIGHT/WED MORNING AS THERMAL TROF WITH 850MB TEMPS AROUND
-4C WILL BE CENTERED OVER THE AREA. 00Z/12Z MEDIUM RANGE GUIDANCE
SUGGESTS THE NEXT SHORTWAVE ROUNDING THE WRN CANADA RIDGE WILL PASS
ACROSS NRN ONTARIO SAT WITH ASSOCIATED COLD FRONT MOVING ACROSS THE
UPPER LAKES. ALTHOUGH THIS A NEW DEVELOPMENT WITH THE 00Z
GUIDANCE...THE 12Z RUNS BACK UP THE POSSIBILITY. AS A RESULT..SCHC
TO LOW CHC POPS HAVE BEEN INTRODUCED FOR SAT.
AS FOR TEMPS...THE PATTERN THIS WEEK FAVORS NORMAL TO BLO NORMAL
TEMPS FOR UPPER MI ON THE MAJORITY OF DAYS. NIGHTTIME MINS WILL
STILL BE DOWN TO AROUND FREEZING IN THE INTERIOR ON AT LEAST A
COUPLE OF DAYS. TUE WILL BE ONE OF THE WARMER DAYS AS W TO SW FLOW
DEVELOPS AHEAD OF APPROACHING SHORTWAVE/COLD FRONT WHICH ARRIVES IN
THE AFTN/EVENING. WARMTH ON TUE WILL DEPEND ON TIMING OF THE COLD
FRONT/CLOUD COVER AND SHRA...BUT RIGHT NOW...IT LOOKS LIKE MUCH OF
THE AREA SHOULD SEE HIGHS IN THE 60S. MUCH COOLER WEATHER...
ESPECIALLY NOTABLE CLOSE TO LAKE SUPERIOR...WILL FOLLOW FOR WED
UNDER BRISK N WINDS. TEMPS WILL FALL BACK SOLIDLY BLO NORMAL WITH
READINGS CLOSE TO LAKE SUPERIOR NO HIGHER THAN AROUND 40F. EXPECT
CONSIDERABLE CLOUD COVER WITH 850MB THERMAL TROF OVER THE AREA...
FURTHER SUPPORTING COOL CONDITIONS. MODERATION WILL OCCUR THU WITH
MORE WARMING FRI AND POSSIBLY ON INTO SAT...DEPENDING ON TIMING OF
THE COLD FRONT THAT IS NOW EXPECTED TO ARRIVE THIS WEEKEND. RECENT
GFS/ECMWF RUNS HAVE INDICATED THAT FRI AND/OR SAT COULD BE QUITE
WARM WITH TEMPS WELL ABOVE NORMAL IN THE 70S. WILL TURN COOLER AGAIN
FOR SUN. LOOKING FARTHER AHEAD...NAEFS OUTLOOKS ARE SUGGESTING A
TREND TOWARD AN OVERALL SOMEWHAT ABOVE NORMAL TEMP REGIME DURING THE
SECOND WEEK OF MAY.
EVEN IF MOST AREAS SEE SOME PCPN TUE...AMOUNTS WON`T BE SIGNIFICANT
AND WON`T REALLY AFFECT WHAT IS BECOMING AN EXTENDED DRY SPELL FOR
UPPER MI. IN ADDITION...MOSTLY COOL CONDITIONS...ESPECIALLY AT
NIGHT...WILL KEEP GREENUP SLOW. THUS...FIRE WX WILL BE AN ISSUE AT
TIMES FOR THE NEXT 1-2 WEEKS. THIS WEEK...TUE STILL LOOKS LIKE THE
DAY OF MOST CONCERN AS IT SHOULD BE A WARMER DAY WITH POTENTIAL OF
BREEZY W TO SW WINDS AHEAD OF APPROACHING COLD FRONT. HOWEVER...IF
CLOUDS/-SHRA ARRIVE SOONER...FIRE CONCERNS WILL BE EASED. IF THE
COLD FRONT MATERIALIZES FOR NEXT WEEKEND...ANOTHER DAY WITH ELEVATED
FIRE WX CONCERNS WILL OCCUR ON THE DAY PRIOR TO ITS PASSAGE OR THE
DAY OF FROPA...EITHER FRI OR SAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 128 PM EDT SUN MAY 1 2016
CONDITIONS WILL GENERALLY REMAIN VFR WITH LIGHT WINDS THROUGHOUT THE
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 PM EDT SUN MAY 1 2016
A WEAK HIGH PRESSURE RIDGE SAGGING SOUTHEASTWARD ACROSS LAKE
SUPERIOR TONIGHT THROUGH MONDAY WILL KEEP WINDS BLO 20 KNOTS. WSW
WINDS WILL QUICKLY INCREASE TO AS HIGH AS 20 KT LATE MON NIGHT INTO
TUESDAY MORNING AHEAD OF LOW PRESSURE SYSTEM APPROACHING FROM
NORTHERN ONTARIO. WINDS WILL BECOME N TO NW AT AROUND 20 KNOTS LATE
TUESDAY AFTERNOON AND INCREASE TO AROUND 25 KNOTS OVER EASTERN LAKE
SUPERIOR LATE TUESDAY NIGHT INTO WEDNESDAY BEHIND THIS LOW. ANOTHER
HIGH PRESSURE RIDGE BUILDING OVER THE UPPER GREAT LAKES WILL
DIMINISH WINDS THURSDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 PM EDT SUN MAY 1 2016
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 409 PM EDT SUN MAY 1 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A REX BLOCK OVER WRN NOAM
RESULTING IN WEAK NW FLOW INTO THE NRN LAKES. AT THE SFC...A RIDGE
EXTENDED FROM JAMES BAY INTO WRN LAKE SUPERIOR BRINGING N TO NE
WINDS INTO MOST OF UPPER MI. HOWEVER...THE GRADIENT WAS WEAK ENOUGH
TO ALLOW LAKE BREEZE DEVELOPMENT OFF OF LAKE MICHIGAN. VIS LOOP
SHOWED CU OVER THE INLAND WEST AND LOW LEVEL CONVERGENCE AREA IN
THE E HALF.
TONIGHT...HIGH PRESSURE BUILDING INTO UPPER MI WILL BRING MOSTLY
CLEAR SKIES AND LIGHT WINDS TONIGHT. FAVORABLE RADIATIONAL COOLING
CONDITIONS WILL ALLOW TEMPS TO DROP INTO THE UPPER 20S INLAND WEST
AND TO THE LOWER TO MID 30S OVER THE REST OF THE CWA.
MONDAY...DRY CONDITIONS WILL CONTINUE WITH SFC RIDGING ACROSS THE
AREA AND THE ACTIVE WEATHER ASSOCIATED WITH A MID LEVEL SHRTWV
REMAINING WELL TO THE SE OVER THE ERN LAKES. A WEAK GRADIENT WILL
AGAIN ALLOW PROMINENT LAKE BREEZE DEVELOPMENT WITH THE LAKE SUPERIOR
BREEZE REACHING THE FARTHEST INLAND. SUNSHINE AND DEEP MIXING WILL
RESULT IN TEMPS INTO THE LOW TO MI 60S INLAND WEST WITH 50S NEAR THE
GREAT LAKES ALONG WITH CU DEVELPMENT SIMILAR TO TODAY.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM EDT SUN MAY 1 2016
MONDAY...A DECAYING MID-LEVEL RIDGE TRACKING SE ACROSS THE CWA ON
MONDAY WILL LEAD TO WIDESPREAD LAKE BREEZE DEVELOPMENT ALONG WITH
DIURNAL CUMULUS INLAND. SOME GUIDANCE IS INDICATING LIGHT PRECIP
INLAND ALONG THE LAKE BREEZE BOUNDARIES...BUT SHALLOW CLOUD DEPTHS
AND HIGH BASES SHOULD PREVENT PRECIP FORMATION.
MONDAY NIGHT THROUGH TUESDAY...A POTENT MID-LEVEL TROUGH DROPPING
SSE ACROSS NORTHERN ONTARIO COMBINED WITH AN APPROACHING LEFT EXIT
OF AN UPPER JET WILL QUICKLY TRACK ACROSS THE CWA LATE MONDAY NIGHT
THROUGH TUESDAY. THE MAIN PLAYER FOR PRECIP CHANCES WILL BE AN
ASSOCIATED SFC COLD FRONT ARRIVING ON TUESDAY. GUIDANCE CONTINUES TO
FAVOR A MID TO LATE AFTERNOON FROPA...ALLOWING FOR SOME DIURNAL
HEATING AHEAD OF THE FRONT. WITH THIS DIURNAL ASSISTANCE...SCATTERED
SHOWERS TO NUMEROUS WILL FORM ALONG THE FRONT. LIMITED LOW-LEVEL
MOISTURE AND HIGH LCL HEIGHTS WILL LIMIT ANY DECENT THUNDERSTORM
ACTIVITY...BUT A FEW RUMBLES WILL BE POSSIBLE.
TUESDAY HAS ALSO HAD THE FOCUS OF FIRE WX CONCERNS FOR SEVERAL DAYS
NOW. BY THEN...THE ENTIRE CWA WILL HAVE HAD A WEEK OF DRYING SINCE
THE WIDESPREAD RAIN EARLY LAST WEEK. DAYTIME HEATING SUPPORTS TEMPS
INTO THE 60S INLAND AND MIN RH VALUES AROUND 30 PERCENT.
ADDITIONALLY...WEST WINDS WILL GUST OVER 20MPH LATE MORNING INTO THE
AFTERNOON. THESE FACTORS ALL SUPPORT INCREASED WILDFIRE
DANGER...ESPECIALLY ACROSS THE INTERIOR WEST. HOWEVER...A COUPLE
FACTORS MAY LIMIT TEMPERATURES. THE FIRST WOULD BE AN EARLY ARRIVAL
OF MID TO HIGH CLOUDS IN THE MORNING. THE SECOND IS AN EARLIER
FRONTAL PASSAGE IN THE EARLY AFTERNOON.
TUESDAY NIGHT AND WEDNESDAY...SHOWER AND POSSIBLY THUNDERSTORM
ACTIVITY WILL END FROM NW TO SE DURING THE EVENING. THEN...WRAP-
AROUND MOISTURE IN CYCLONIC FLOW BEHIND THE MID-LEVEL TROUGH WILL
CONTINUE TO SUPPORT ISOLATED TO SCATTERED SHOWER ACTIVITY LATE TUE
NIGHT THROUGH WED. THIS IS ESPECIALLY TRUE FOR UPSLOPE AREAS ALONG
THE LAKE SUPERIOR SHORE. THERMO PROFILES SUPPORT A POSSIBLE MIX WITH
SNOW FOR MAINLY THE HIGH TERRAIN OF THE NORTH LATE WED NIGHT. PLENTY
OF LOW CLOUDS AND N TO NW WINDS FAVOR A CHILLY WEDNESDAY ACROSS
UPPER MI...WITH HIGHS POSSIBLY FAILING TO REACH 40 EAST ALONG THE
IMMEDIATE LAKE SUPERIOR SHORE.
THURSDAY THROUGH SATURDAY...HIGH PRESSURE WILL BUILD ACROSS THE MS
VALLEY WHILE THE MID-WEEK TROUGH MERGES WITH A SOUTHERN STREAM
SYSTEM TO FORM DEEP TROUGHING ACROSS THE EASTERN CONUS.
EXPECT DRY CONDITIONS AND GRADUALLY MODERATING TEMPS...WITH POSSIBLY
SOME CLOUD COVER EXTENDING WESTWARD FROM THE EASTERN TROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 128 PM EDT SUN MAY 1 2016
CONDITIONS WILL GENERALLY REMAIN VFR WITH LIGHT WINDS THROUGHOUT THE
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 PM EDT SUN MAY 1 2016
A WEAK HIGH PRESSURE RIDGE SAGGING SOUTHEASTWARD ACROSS LAKE
SUPERIOR TONIGHT THROUGH MONDAY WILL KEEP WINDS BLO 20 KNOTS. WSW
WINDS WILL QUICKLY INCREASE TO AS HIGH AS 20 KT LATE MON NIGHT INTO
TUESDAY MORNING AHEAD OF LOW PRESSURE SYSTEM APPROACHING FROM
NORTHERN ONTARIO. WINDS WILL BECOME N TO NW AT AROUND 20 KNOTS LATE
TUESDAY AFTERNOON AND INCREASE TO AROUND 25 KNOTS OVER EASTERN LAKE
SUPERIOR LATE TUESDAY NIGHT INTO WEDNESDAY BEHIND THIS LOW. ANOTHER
HIGH PRESSURE RIDGE BUILDING OVER THE UPPER GREAT LAKES WILL
DIMINISH WINDS THURSDAY INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...- NONE -
LONG TERM...KLUBER
AVIATION...JLB
MARINE...- NONE -
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
559 PM CDT SUN MAY 1 2016
.SHORT TERM... (Through Late Tonight)
Issued at 324 PM CDT Sun May 1 2016
Clouds will continue to move southeast and will overspread the area
by mid evening as upper trough back over eastern Nebraska drops
southeast into Missouri and Illinois. Isolated afternoon showers
and thunderstorms should diminish by early this evening with the
loss of daytime heating. Some isolated showers may begin to develop
toward morning underneath the upper trough over central and
northeast Missouri. Lows tonight will fall into the middle 40s to
around 50s.
Britt
.LONG TERM... (Monday through Next Sunday)
Issued at 324 PM CDT Sun May 1 2016
(Monday through Wednesday)
GFS/ECMWF are in relatively good agreement that upper trough will
move across the area tomorrow with relatively deep layer moisture.
Will carry chance PoPs for much of the area for this reason. Drier
air will begin to move into the area by Monday night, so will go
with mainly dry conditions. A second trough moves across the area
on Tuesday which begins the switchover in the upper pattern to
northwesterly flow. GFS/ECMWF are still showing a third upper
trough moving across the Great Lakes and the Midwest on Wednesday
that will bring an attendant cold front across Missouri and Illinois.
Models indicate that best low level moisture and forcing will
still limit rain chances to the eastern part of the CWA.
Monday still looks quite cool with clouds, showers, and cold air
advection. Tuesday will be slightly warmer with less clouds and
winds turning out of the west. Wednesday will see near steady
temperatures during the afternoon behind the front.
(Thursday through Sunday)
CONUS will be in highly amplified upper flow late week into next
weekend because of an omega block that will set up over North
America. It still looks like we will be dry through at least
Saturday as we will lie under northwesterly flow aloft and a large
surface high will be moving across Missouri and Illinois. By next
weekend, the GFS and ECMWF show the upper ridge moving over us and
the low level flow becoming southwesterly across the Midwest. This
may allow for some return of Gulf moisture into our area by late in
the weekend. Have added a chance of thunderstorms on Sunday as both
the GFS and ECMWF are hinting at a frontal boundary moving back into
the area. This will also cause temperatures to climb from below
normal on Thursday with 850mb temperatures around 5C to above normal
temperatures over the weekend with southwesterly surface flow and
850mb temperatures around 15C.
Britt
&&
.AVIATION... (For the 00z TAFs through 00z Monday Evening)
Issued at 455 PM CDT Sun May 1 2016
Surface low over southeast IL will move eastward tonight. Any
showers/storms should be east of the taf sites this evening. MVFR
cigs in UIN should drop back down into the IFR catagory later this
evening. The low level cloud cover over northern MO will advect
south-southeastward into COU and the St Louis metro area later
this evening and overnight, leading to MVFR cigs initially, then
dropping into the IFR catagory late tonight/early Monday morning.
There will also be light fog late tonight and early Monday
morning. The cloud ceiling will gradually rise into the MVFR
catagory late Monday morning, and possibly into the VFR catagory
by late Monday afternoon. An upper level disturbance will bring
widely scattered showers to the area on Monday. W-nwly surface
wind will become more n-nwly on Monday.
Specifics for KSTL: MVFR cigs will move into STL late this
evening, then drop into the IFR catagory late tonight along with
light fog. The fog will dissipate by late morning along with the
cigs rising into the MVFR catagory. The ceiling may rise into the
VFR catagory by late Monday afternoon or early Monday evening.
There may be a few showers on Monday. Nwly surface wind will
continue through the period, weakening early this evening.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Saint Louis MO
325 PM CDT SUN MAY 1 2016
.SHORT TERM... (Through Late Tonight)
Issued at 324 PM CDT Sun May 1 2016
Clouds will continue to move southeast and will overspread the area
by mid evening as upper trough back over eastern Nebraska drops
southeast into Missouri and Illinois. Isolated afternoon showers
and thunderstorms should diminish by early this evening with the
loss of daytime heating. Some isolated showers may begin to develop
toward morning underneath the upper trough over central and
northeast Missouri. Lows tonight will fall into the middle 40s to
around 50s.
Britt
.LONG TERM... (Monday through Next Sunday)
Issued at 324 PM CDT Sun May 1 2016
(Monday through Wednesday)
GFS/ECMWF are in relatively good agreement that upper trough will
move across the area tomorrow with relatively deep layer moisture.
Will carry chance PoPs for much of the area for this reason. Drier
air will begin to move into the area by Monday night, so will go
with mainly dry conditions. A second trough moves across the area
on Tuesday which begins the switchover in the upper pattern to
northwesterly flow. GFS/ECMWF are still showing a third upper
trough moving across the Great Lakes and the Midwest on Wednesday
that will bring an attendant cold front across Missouri and Illinois.
Models indicate that best low level moisture and forcing will
still limit rain chances to the eastern part of the CWA.
Monday still looks quite cool with clouds, showers, and cold air
advection. Tuesday will be slightly warmer with less clouds and
winds turning out of the west. Wednesday will see near steady
temperatures during the afternoon behind the front.
(Thursday through Sunday)
CONUS will be in highly amplified upper flow late week into next
weekend because of an omega block that will set up over North
America. It still looks like we will be dry through at least
Saturday as we will lie under northwesterly flow aloft and a large
surface high will be moving across Missouri and Illinois. By next
weekend, the GFS and ECMWF show the upper ridge moving over us and
the low level flow becoming southwesterly across the Midwest. This
may allow for some return of Gulf moisture into our area by late in
the weekend. Have added a chance of thunderstorms on Sunday as both
the GFS and ECMWF are hinting at a frontal boundary moving back into
the area. This will also cause temperatures to climb from below
normal on Thursday with 850mb temperatures around 5C to above normal
temperatures over the weekend with southwesterly surface flow and
850mb temperatures around 15C.
Britt
&&
.AVIATION... (For the 18z TAFs through 18z Monday Afternoon)
Issued at 106 PM CDT Sun May 1 2016
Specifics for KCOU: KCOU is far enough west that VFR conditions
should prevail for the first 0-6 hours of the valid TAF pd.
Thereafter, MVFR cigs are expected for most of the night. Ceilings
may fall to IFR late tonight, but confidence was too low to
include in the TAF attm.
Specifics for KUIN: IFR conditions are expected for at least the
next few hours. Minor improvement is possible during the late
afternoon, but cigs should fall back to IFR this evening.
Scattered rain showers are possible after 20z.
Specifics for KSTL, KSUS, KCPS: IFR and MVFR cigs extended farther
south late this morning than the models had previously predicted,
and IFR/MVFR cigs are expected to remain in place through the
afternoon based on upstream satellite imagery and METARs. Cigs
are expected to fall to IFR again tonight, likely after 06z based
on RAP and local WRF soundings in BUFKIT. Light fog is also
possible overnight. Rain showers are possible after 12z, but the
St. Louis metro area should be on the northern fringe of the rain
shield.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1234 PM CDT SUN MAY 1 2016
.SYNOPSIS...
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM CONTINUES TO SLOWLY PUSH ACROSS SOUTHEASTERN
NEBRASKA THIS MORNING. DEFORMATION BAND STRETCHES ACROSS NORTH
CENTRAL INTO SOUTHWEST NEBRASKA. PRECIP TYPE GENERALLY RAIN EAST
OF HIGHWAY 83 THEN A MIX OR A CHANGE TO ALL SNOW TO THE WEST OF
83. TEMPS HAVE HELD FAIRLY STEADY MOST OF THE NIGHT IN THE MID
30S TO AROUND 40...HOWEVER THE LAST HOUR HAS SEEN A RISE OF A
DEGREE IN A FEW SPOTS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SUN MAY 1 2016
LOW PRESSURE SYSTEM WILL FINALLY PUSH FAR ENOUGH TO THE EAST THAT
AN END TO THE RAIN/SNOW IS EXPECTED TODAY. THE BAND HAS BECOME
MORE BROKEN OVERNIGHT...WITH THIS TREND EXPECTED TO CONTINUE
THROUGH THE MORNING HOURS. MOST MODELS HAVE THE CWA DRY FOR THE
AFTN...HOWEVER THE LATEST HRRR KEEPS THE EASTERN ZONES IN LIGHT
SHOWERS INTO THE AFTERNOON HOURS. CURRENT THINKING IS THE DRY AIR
FROM THE NORTH WILL GET DRAWN INTO THE AREA...ALONG WITH RISING
TEMPS DUE TO DAYTIME HEATING AND WARM AIR ADVECTION FROM
DEPARTING LOW...WITH THE FORECAST PRIMARILY DRY. WITH TEMPS
ALREADY STARTING TO RISE...EXPECT THE THREAT FOR SNOW TO QUICKLY
END WITH LIQUID PRECIP TO BE THE PREDOMINATE P-TYPE. WILL HAVE TO
MONITOR FOR THE AFTERNOON AS SOME ISOLATED SPRINKLES/LIGHT RAIN
SHOWERS CAN NOT BE RULED OUT.
CLOUDS LINGERING THROUGH THE DAY AND WILL LIMIT HEATING. HAVE
GONE WITH THE COOLER GUIDANCE AS MOST GUIDANCE HAS BEEN TOO WARM
THE PAST FEW DAYS. BY TONIGHT DECREASING CLOUDS COMBINE WITH
LIGHT WINDS FOR A GOOD SET UP FOR RADIATIONAL COOLING. TEMPS
LIKELY TO DIP BELOW FREEZING FOR MOST WESTERN LOCATIONS. STILL A
LITTLE EARLY FOR ANY FROST HEADLINES...AND MANY LOCATIONS WITH
THE COOLER TEMPS EXPECTED...JUST SAW ACCUMULATING SNOWS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN MAY 1 2016
MID RANGE...MONDAY AND TUESDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION. IN THE WAKE OF THE CLOSED LOW THAT
BROUGHT PERSISTENT RAIN AND SNOW TO THE AREA... A SHORTWAVE WILL
TRAVERSE THE SANDHILLS LATE MONDAY.
MONDAY... MADE LITTLE CHANGE TO MAX TEMPS EXCEPT FOR COOLED THE
SOUTHWEST CORNER NEAR COLORADO TO ACCOUNT FOR POSSIBLE REMAINING
SNOW PACK. CURRENT FORECAST HIGHS ARE SLIGHTLY BELOW MOS GUIDANCE...
BUT INCREASING CLOUD COVER WITH THE SHORTWAVE MAY HELP OFFSET WAA.
WITH BETTER AGREEMENT AMONG THE MODELS REGARDING THE WAVE AND MID
LEVEL FRONTOGENESIS... INTRODUCED SCHC POPS BEGINNING 18Z. NAM KEEPS
THE AREA DRY DUE TO OVERALL LACK OF MOISTURE AND LIFT. GFS AND EURO
ARE MORE BULLISH WITH THE MOISTURE AND DEPICT AN AREA OF 500-700HPA
SATURATION OVER THE CWA LATE MONDAY. LIFT IS STILL RATHER WEAK IN
GFS SOUNDINGS... BUT MOISTURE AND FGEN MAY BE STRONG ENOUGH IN THE
MID LEVELS TO OVERCOME RELATIVELY DRY AIR NEAR THE SURFACE.
TUESDAY... SHUT OFF POPS BY 12Z ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA AS THE WAVE IS FAIRLY QUICK PASSING. SWITCHED PTYPE TO
RASN WEST OF NEB HWY 61 WHERE HIGHER ELEVATION AND COOLER LOW TEMPS
WOULD SUPPORT A MIX. AS THIS LOOKS LIKE A LIGHT PRECIP EVENT AT
MOST... SHOULD NOT BE ADEQUATE DYNAMIC COOLING TO RESULT IN ALL SNOW
AND THUS KEPT SNOW AMOUNTS AT ZERO. DID PUSH MAX TEMPS UP A
DEGREE... WHICH LEANS TOWARD MAV AND MET. SKY SHOULD CLEAR OUT
QUICKLY BEHIND THE SHORTWAVE... AND MODELS ARE CONSISTENT WITH
NOTICEABLE WAA ACROSS THE REGION. GFS AND NAM BRING H85 TEMPS TO 11C
NORTH CENTRAL AND 14C FAR WEST. PLENTY OF DRY AIR ALOFT WILL ALLOW
FOR UNINHIBITED MIXING TO NEAR 700HPA... AND WITH A SLIGHT DOWNSLOPE
COMPONENT AT 850HPA... HIGHS SHOULD BE ABLE TO REACH NEAR 70F.
LONG RANGE...WEDNESDAY THROUGH SATURDAY... THIS PERIOD IS DOMINATED
BY A BLOCKING PATTERN ALOFT... RESULTING IN AN AMPLIFIED RIDGE OVER
THE GREAT PLAINS. WEAK WAA AND DRY WEATHER CONTINUE THROUGHOUT THE
WEEK WITH HIGHS IN THE LOWER/MID 70S. MOISTURE ADVECTION REALLY
TAKES SHAPE LATE WEEK AS LOW LEVEL FLOW TURNS SOUTHERLY. GFS AND
EURO ARE PUSHING SFC DEW POINTS INTO THE LOWER 50S ALONG/EAST OF HWY
83 THURSDAY PM AND MID/UPPER 50S FRIDAY PM. BOTH MODELS HAVE A LOW
LEVEL JET DEVELOPING FRIDAY NIGHT. THE BRUNT OF THE SPEED
CONVERGENCE IS OVER THE SANDHILLS... SO FELT CONFIDENT ENOUGH TO
RETAIN CHC POPS OVERNIGHT. THE WESTERN CLOSED LOW REACHES THE
SOUTHWEST DESERT SATURDAY... WHICH BEGINS THE RIDGE BREAKDOWN PHASE
FOR WESTERN NEBRASKA. THE H3 JET FEATURES A 100+KT STREAK POINTED
TOWARD EASTERN COLORADO SATURDAY PM... AND WITH DEW POINTS NOW
PUSHING 60F... THUNDERSTORMS ARE A DISTINCT POSSIBILITY. GFS AND
EURO ARE IN SURPRISINGLY GOOD AGREEMENT WITH THE SFC LOW NEAR KSNY
AND H5 LOW OVER KLAS 00Z SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1234 PM CDT SUN MAY 1 2016
AS LOW PRESSURE DRIFTS EAST THIS AFTERNOON...NORTHERLY FLOW WILL
PROMOTE THE DEVELOPMENT OF WEAKLY DEVELOPED CUMULUS ACROSS
NORTHERN NEBRASKA AND THE CENTRAL SANDHILLS. THE GUIDANCE PROJECTS
THESE CLOUDS TO REMAIN AOA 4000FT AGL...THUS VFR SHOULD PREVAIL
FOR MOST SITES. FAR EASTERN TERMINALS SUCH AS KONL AND KBBW ARE
STILL DEALING WITH MVFR STRATUS ASSOCIATED WITH THE DEPARTING
LOW...BUT CEILINGS ARE FORECAST TO IMPROVE THROUGH THE AFTERNOON.
WIND SPEEDS WILL BE BREEZY THROUGH TODAY...BUT WEAKEN OVERNIGHT AS
THE PRESSURE GRADIENT RELAXES. THE WIND WILL LARGELY TURN WESTERLY
LATE IN THE FORECAST PERIOD. OVERALL FORECAST CONFIDENCE IS HIGH.
&&
.HYDROLOGY...
ISSUED AT 819 AM CDT SUN MAY 1 2016
AN AREAL FLOOD WARNING HAS BEEN ISSUED ALONG THE UPPER REACHES OF
THE ELKHORN RIVER. THE RIVER GAGE AT ATKINSON HAS JUST REACHED
FLOOD STAGE AND IS LIKELY TO REMAIN SLIGHTLY ABOVE FLOOD STAGE
FOR AT LEAS THE NEXT FEW DAYS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MASEK
SHORT TERM...MASEK
LONG TERM...SNIVELY
AVIATION...JACOBS
HYDROLOGY...ROBERG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
316 PM EDT SUN MAY 1 2016
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH OF THE AREA THIS EVENING WITH
SHOWERS AND THUNDERSTORMS CONTINUING ACROSS THE AREA. GOOD RAIN
CHANCES ARE EXPECTED MONDAY AND TUESDAY AS A LOW PRESSURE SYSTEM
SLOWLY APPROACHES THE COAST. A COLD UPPER TROUGH WILL BRING
SCATTERED SHOWERS AND COOLER TEMPERATURES FROM LATE WEDNESDAY INTO
NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 3 PM SUNDAY...WARM FRONT IN PROCESS OF MOVING NORTH ACROSS
THE FORECAST AREA. ATTENDANT PRECIP IS A BIT MORE VIGOROUS AND
WIDESPREAD THAN EARLIER ANTICIPATED AND THINK THAT GUIDANCE
UNDERESTIMATED ATMOSPHERIC INSTABILITY AND STRENGTH OF UPPER
SUPPORT. IN ANY CASE BASED ON ANALYSIS OF MORNING SOUNDINGS STILL
THINK THAT SEVERE POTENTIAL IS MARGINAL BUT CANNOT RULE OUT THE
ODD STRONG THUNDERSTORM ACCOMPANIED BY GUSTY WINDS AND SMALL HAIL.
AREA OBSERVATIONS HOWEVER HAVE NOT SHOWN ANY STRONG WINDS
ACCOMPANYING PRESENT CONVECTION AND SOUNDINGS SHOW THAT ANY UPPER
WINDS THAT MIX DOWN WOULD BE IN THE 25 KT RANGE. OF COURSE...RAIN-
COOLED DOWNDRAFTS COULD BE MUCH STRONGER.
HAVE LEANED ON THE HRRR FOR THE VERY NEAR TERM AS IT HAS INITIALIZED
WELL. THIS DEPICTS OUR PRESENT WIDESPREAD CONVECTION...TAPERING OFF
THIS EVENING AND OVERNIGHT. S TO SW FLOW IN WAKE OF WARM FROPA WILL
KEEP OVERNIGHT TEMPERATURES WELL ABOVE NORMAL...IN THE MID TO UPPER
60S MOST PLACES.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...GOOD CHANCES FOR RAIN CONTINUE THROUGH THE
SHORT TERM AS A COLD FRONT SLOWLY DROPS SE ACROSS THE EASTERN
CAROLINAS AND AN UPPER TROUGH DEEPENS OVER EASTERN CONUS.
ATMOSPHERE WILL REMAIN MOIST AND MARGINALLY TO MODERATELY UNSTABLE
THROUGH THE PERIOD. BEST CHANCES FOR STRONG TO SEVERE CONVECTION
WILL BE TUESDAY AFTERNOON AND EVENING AS A SERIES OF FACTORS COME
IN TO PLAY...INCLUDING FAVORABLE UPPER WINDS...A SHORT WAVE
TROUGH...AND LIFT ASSOCIATED WITH THE COLD FRONT...IN ADDITION TO
THE AFOREMENTIONED INSTABILITY AND AVAILABLE MOISTURE. COLD FRONT
SHOULD BE POSITIONED MORE OR LESS ALONG THE COAST BY DAYBREAK ON
WEDNESDAY AND EXPECT THAT BULK OF PRECIP WILL HAVE MOVED OFFSHORE
OVERNIGHT ON TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...SURFACE SYSTEM EXITS AS THE PERIOD BEGINS WHILE
ALOFT A MID LEVEL BLOCK WILL START SETTING UP. A COLD FRONT WILL
CROSS THE AREA THU...DRIVEN WELL OFF THE COAST BY LARGE 5H EAST
COAST TROUGH/CUTOFF. THIS CUTOFF WILL FORM THE EASTERN SIDE OF THE
BLOCK AND WILL REMAIN IN PLACE INTO SUNDAY BEFORE SLIDING OFF TO THE
EAST AS MID LEVEL RIDGE OVER LOWER MS VALLEY EXPANDS EAST. MOISTURE
OVER THE SOUTHEAST WILL BE LIMITED FOR MUCH OF THE PERIOD WITH DEEP
WEST AND THEN NORTHWEST FLOW PREVENT ANY MOISTURE RETURN. THERE WILL
BE SOME LINGERING MOISTURE EARLY IN THE PERIOD...AND AN ISOLATED
AFTERNOON/EVENING SHOWER OR THUNDERSTORM WED-FRI CANNOT BE RULED
OUT. HOWEVER COVERAGE WILL BE VERY LIMITED.
IN ADDITION TO DEEP DRY AIR LOW LEVEL NORTHERLY FLOW...AS HIGH
PRESSURE TO THE WEST SLOWLY EXPANDS EAST...WILL DROP NEAR CLIMO
TEMPS WED BELOW TO WELL BELOW CLIMO THU THROUGH SAT. MID LEVEL
RIDGING AND MIGRATION OF THE SURFACE HIGH EAST WILL RESULT IN TEMPS
RETURNING NEAR CLIMO.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
AS OF 17Z...MID-LEVEL IMPULSE PUSHING ACROSS THE CAROLINAS WILL
RESULT IN TEMPO MVFR CIGS/VSBYS INVOF SCATTERED CONVECTION THROUGH
THE AFTERNOON. ANOTHER ROUND POSSIBLE OVERNIGHT INTO MONDAY.
OTHERWISE...A WARM FRONT WILL PUSH NORTH OF THE AREA WITH S-SW
FLOW...WHILE THE WIND FIELD REMAINS SKEWED IN AREAS OF CONVECTION.
VFR CONDITIONS PREVAIL OUTSIDE ANY SHRA/TSRA.
EXTENDED OUTLOOK...MVFR/IFR POSSIBLE FROM CONVECTION MONDAY THROUGH
TUESDAY. PCPN MOST WIDESPREAD MONDAY NIGHT THRU TUESDAY. VFR
CONDITIONS WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SUNDAY...A WARM FRONT WILL MOVE NORTH OF THE WATERS
TODAY...LEAVING SW WINDS OF 10 TO 15 KTS IN ITS WAKE. SEAS WILL
NOT STRAY FAR FROM PRESENT HEIGHTS...RIGHT AROUND 3 FT...THROUGH
THE PERIOD.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...A COLD FRONT WILL APPROACH THE WATERS THROUGH
THE SHORT TERM BUT WILL NOT LIKELY MAKE IT OFFSHORE BEFORE
DAYBREAK ON WEDNESDAY. WINDS WILL STAY SW THROUGH THE PERIOD AND
GENERALLY IN THE 10 TO 15 KT RANGE...ALTHOUGH A TIGHTENING
GRADIENT ON TUESDAY MAY SEE WINDS BUMPED UP TO 15 TO 20 KTS FOR A
TIME IN THE AFTERNOON. EXPECT SEAS OF 2 TO 4 FT THROUGH THE
PERIOD...EXCEPT FOR UP TO 5 FT SHOULD WINDS INCREASE ON TUESDAY.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...OFFSHORE FLOW EXPECTED INTO THE WEEKEND.
PERIOD BEGINS WITH LOW/FRONT COMBO MOVING NORTHEAST OF THE AREA
WITH WESTERLY FLOW OF 10 TO 15 KT. SECOND COLD FRONT MOVES
OFFSHORE ON THU WITH STRONG WEST TO NORTHWEST FLOW DEVELOPING IN
ITS WAKE. PINCHED GRADIENT AND COLD ADVECTION THU NIGHT AND FRI
WILL PUSH WEST WINDS INTO THE 15 TO 20 KT RANGE. GRADIENT AND
ADVECTION RELAX ON FRI AS THE HIGH SLOWLY MOVES EAST AND WINDS
DROP TO 10 TO 15 KT THROUGH FRI NIGHT. SEAS 2 TO 3 FT WED BUILD TO
3 TO 4 FT THU IN RESPONSE TO INCREASED WIND SPEEDS. REDUCTION IN
SPEEDS LATE IN THE PERIOD WILL LEAD TO SEAS FALLING TO 2 TO 3 FT
FRI.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK
SHORT TERM...REK
LONG TERM...III
AVIATION...SRP
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1217 PM EDT SUN MAY 1 2016
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL TRACK EAST ALONG A FRONTAL BOUNDARY
AND INTO OHIO TODAY. THIS WILL ACT AS A FOCUS FOR SHOWERS AND
THUNDERSTORMS TO DEVELOP. THE FRONT WILL WORK INTO SOUTHERN
KENTUCKY AND WEST VIRGINIA TONIGHT...BUT ANOTHER WAVE WILL KEEP
THE CHANCE OF PRECIPITATION IN THE FORECAST FOR MONDAY INTO MONDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MORNING CONVECTION ALONG THE OHIO RIVER HAS JUST ABOUT CLEARED
OUT OF THE ILN FORECAST AREA...WITH LIGHTER RADAR ECHOES WITHIN AN
AREA OF THICK LOW-LEVEL CLOUDS ALSO SHOWING SIGNS OF DISSIPATION.
SATELLITE IMAGERY SUGGESTS THAT PARTIAL CLEARING HAS BEGUN TO WORK
INTO SECTIONS OF THE FORECAST AREA...BUT WITH PATCHES OF STRATUS
AND MID-LEVEL CLOUDS THAT APPEAR UNLIKELY TO COMPLETELY DEPART THE
AREA.
THESE CLOUDS WILL PLAY A PART IN DETERMINING HOW MUCH INSTABILITY
IS ABLE TO BE GENERATED TODAY...AN IMPORTANT KEY TO THE FORECAST
FOR CONVECTION...ESPECIALLY WITH MODEL TIMING AND INTENSITY
EXPECTATIONS STILL FAR FROM A NICE CONSENSUS. BASED ON THE 12Z
KILN SOUNDING AND SREF PROBABILITIES...IF TEMPERATURES IN THE
SOUTHERN HALF OF THE FORECAST AREA ARE ABLE TO GET INTO THE LOWER
70S AS CURRENTLY FORECAST...SBCAPE OF 1200-1800 J/KG WILL BE
ATTAINABLE.
IN TERMS OF TIMING AND PLACEMENT...THIS REMAINS SOMEWHAT IN
QUESTION...BUT RECENT HRRR RUNS HAVE PERHAPS SHOWN THE MOST
PROMISE IN ALIGNING BEST WITH THE OBSERVED SURFACE PATTERN.
ALONG A WEAK AND NEARLY-STATIONARY SURFACE BOUNDARY...SCATTERED
SHOWERS AND STORMS ARE EXPECTED TO DEVELOP IN THE SOUTHERN HALF OF
THE FORECAST AREA BETWEEN 18Z-20Z...MOVING EAST AND OUT OF THE
CWA BY 00Z. ADDITIONAL STORMS MAY DEVELOP FURTHER TO THE NORTHWEST
DURING THE EVENING...AHEAD OF AN INCOMING SHORTWAVE. LOW-LEVEL
FORCING IS NOT IMPRESSIVE...AND SUBSEQUENTLY THE LOW-LEVEL WIND
FLOW IS ALSO FAIRLY WEAK. DEEP-LAYER WEST-SOUTHWESTERLY SHEAR IS
MORE NOTABLE (45-50 KNOTS)...WHICH WILL LIKELY COMBINE WITH THE
INSTABILITY TO PRODUCE A FEW STRONG (TO POSSIBLY SEVERE) STORMS.
SINCE DESTABILIZATION IS ONE OF THE BIGGER QUESTIONS FOR THE
DAY...A ADDITIONAL KILN SOUNDING WILL BE CONDUCTED AT 17Z...IN
ORDER TO ASSESS THE EARLY AFTERNOON ATMOSPHERIC CONDITIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
CONVECTION SHOULD STILL BE ON GOING FROM THE AFTERNOON INTO THE
EARLY EVENING HOURS AS THE FILLING H5 TROF LIFTS OUT OVER THE
GREAT LAKES. HIGHEST POPS WILL BE AT THE BEGINNING OF THE TONIGHT
PERIOD...WITH THE PCPN CHANCES SLOWLY DECREASING FROM SW TO NE
AFTER THE MIDNIGHT HOUR.
A FEW SHOWERS COULD BE LINGERING IN CENTRAL OHIO EARLY MONDAY
MORNING...BEFORE PUSHING OFF TO THE EAST. PCPN WILL REDEVELOP
MONDAY ALONG THE FRONTAL BOUNDARY WHICH HAD DROPPED INTO SRN KY
DURING SUNDAY NIGHT. ANOTHER WAVE ON THE FRONT WILL PUSH PCPN
INTO THE REGION MONDAY AFTERNOON. HIGHS ON MONDAY WILL BE MUCH
COOLER THAN SUNDAY...WITH HIGHS ONLY MAKING IT IN THE UPPER 50S IN
THE NORTH. THE SOUTHEAST COUNTIES SHOULD MAKE IT INTO THE UPPER
60S HOWEVER.
H5 ENERGY DIGGING DOWN FROM CANADA INTO THE OHIO AND TENNESSEE
VALLEYS WILL KEEP A LINGERING CHANCE OF SHOWERS ACROSS THE
SOUTHERN COUNTIES ON TUESDAY. HIGHS WILL BE IN THE MID 60S ACROSS
THE ENTIRE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
NUMERICAL MODEL SOLNS GENERALLY SIMILAR WITH NRN STREAM TROF
SHARPENING UP AND DIGGING SOUTH AT MID WEEK. THIS WILL ALLOW A SFC
COLD FRONT TO DROP SOUTH THRU ILN/S FA WEDNESDAY. INSTABILITY IS
MARGINAL AT BEST...SO AT THIS TIME HAVE ELECTED TO KEEP PCPN
MENTION TO CHANCE OF SHOWERS. TEMPERATURES WILL CONTINUE TO REMAIN
CLOSE TO NORMAL WITH HIGHS WED FROM THE MID 60S NORTH TO AROUND 70
SOUTH.
DIGGING TROF DEVELOPS INTO DEEP LARGE CLOSED LOW WHICH WILL CONTINUE
TO INFLUENCE OUR WEATHER THRU AT LEAST THE END OF THE WEEK. THIS
FEATURE WILL KEEP CHANCE POPS FOR SHOWERS IN THE FCST THURSDAY AND
FRIDAY. MAY HAVE TO INCLUDE A MENTION OF SHOWERS IN THE EAST ON
SATURDAY WITH THE SOME EVIDENCE THAT MOISTURE WILL CONTINUE TO WRAP
AROUND THIS LARGE LOW. FOR NOW HAVE OPTED FOR DRY SOLN SATURDAY.
TEMP WISE...UNDER THE INFLUENCE OF THIS LOW...BOTH THURSDAY AND
FRIDAY WILL BE BELOW NORMAL WITH HIGHS FROM THE UPPER 50S NORTH TO
THE MID 60S SOUTH. READINGS WILL ONLY MODERATE A LTL SATURDAY WITH
HIGHS FROM THE LOWER 60S NORTH THE UPPER 60S SOUTH.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
SOME PATCHES OF MVFR CEILINGS WILL REMAIN IN PLACE FOR ANOTHER FEW
HOURS. SHOWER AND THUNDERSTORM DEVELOPMENT IS EXPECTED OVER THE
NEXT SEVERAL HOURS AS WELL...AND A TEMPO GROUP FOR SHOWERS HAS
BEEN INCLUDED FOR MOST OF THE TAF SITES THIS AFTERNOON. THE
GREATEST CHANCE FOR THUNDERSTORMS IS LIKELY TO OCCUR SOUTH AND
EAST OF THE AIRPORTS...BUT THUNDER COULD BE INCLUDED IN THE TAFS
IF NECESSARY IN FUTURE UPDATES.
WINDS WILL SHIFT FROM THE SOUTHWEST TO THE NORTHWEST GOING THROUGH
THE OVERNIGHT HOURS. ANOTHER CHANCE OF PRECIPITATION WILL OCCUR
LATE TONIGHT AND INTO THE OVERNIGHT HOURS...MORE LIKELY FOR THE
DAYTON AND COLUMBUS TAF SITES. SOME MVFR CONDITIONS WILL BE
POSSIBLE. HOWEVER...BY EARLY MONDAY MORNING...LOW-END MVFR
CEILINGS (POSSIBLY IFR) WILL MOVE INTO THE NORTHERN TAF SITES.
OUTLOOK...MVFR CEILINGS MAY OCCUR ON MONDAY MORNING. MVFR
VISIBILITIES IN RAIN ARE ALSO POSSIBLE ON MONDAY. MVFR CEILINGS
ARE POSSIBLE AGAIN WEDNESDAY NIGHT INTO THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO/SITES
NEAR TERM...HATZOS/SITES
SHORT TERM...SITES
LONG TERM...AR
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS Tulsa OK
303 PM CDT SUN MAY 1 2016
.DISCUSSION...
Showers lifting northeast across western OK will graze portions of
NE OK this afternoon. This activity should gradually dissipate
toward 00z as the isentropic lift forcing it weakens. Upper
shortwave trough over AZ/NM will slide northeast across our area
tonight. The 12z GFS/ECMWF and latest runs of the experimental
HRRR bring showers across NE OK tonight along the track of the
system. Farther to the south over west TX...increasing ~800 mb
frontogenetic lift in association with the upper wave will
produce one or more bands of rain and possibly a few lightning
strikes late tonight. This activity will spread northeast along
the frontal surface with the HRRR suggesting that it will clip
southeast OK going into Monday morning. Will carry higher chance
pops along the track of the upper wave up north...and down south
where it is most likely banded precip will occur...and only slight
chance pops in between.
Temperatures through Monday night...highs and lows...will run
roughly 10 degrees below average for this time of year. A warming
trend is expected by midweek...with highs returning to the 80s for
the latter part of the week.
The upper air pattern next week will be characterized by a deep
upper trough over the East and Gulf with a ridge over the Rockies.
Rich Gulf moisture will be scoured out by this pattern...with
tranquil weather expected. The upper features will slowly shift
east...with ridging over the Plains by the end of the week.
Eventually a deep upper trough over the West will eventually move
into the Plains early next week...and this will be our next chance
of storms. The moisture quality this system will have to work with
will not be as good as what we saw the last week of April however.
This may mitigate the overall severe potential.
Lacy
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 47 65 45 72 / 40 10 0 10
FSM 52 69 47 71 / 20 10 10 0
MLC 50 66 44 71 / 20 10 0 10
BVO 46 65 40 72 / 40 10 0 10
FYV 47 63 39 67 / 20 10 10 10
BYV 48 63 42 67 / 20 20 10 10
MKO 48 65 44 71 / 20 10 0 0
MIO 47 63 41 70 / 40 20 10 0
F10 48 65 44 71 / 20 10 0 0
HHW 54 70 46 72 / 30 30 0 10
&&
.TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS Tulsa OK
1246 PM CDT SUN MAY 1 2016
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR conditions across Eastern Oklahoma and Northwest Arkansas early
this afternoon should give way to MVFR ceilings from northwest to
southeast this afternoon and tonight. At the same time...rain
chances will become possible across the region through tonight as
an upper level low shifts eastward. Will continue prob30 groups
for precip timing across all TAF sites. MVFR ceilings are expected
to remain common over Eastern Oklahoma and Northwest Arkansas
through the end of the TAF period Monday morning behind the
exiting precip chances.
&&
.PREV DISCUSSION... /ISSUED 1023 AM CDT SUN MAY 1 2016/
..UPDATE...
DISCUSSION...
This morning...on a synoptic scale...an upper low was positioned
over Arizona and New Mexico while a second upper low was located
over Kansas and Nebraska. Southerly upper flow from the Arizona
upper low was converging with the northerly upper flow from the
Kansas upper low...creating a mid level frontal boundary to the
northwest of Eastern Oklahoma and Northwest Arkansas. A few
showers had developed along this boundary early this
morning...though had dissipated by mid morning as they ran into
drier air over North Central Oklahoma. Across Eastern Oklahoma and
Northwest Arkansas at mid morning...mostly clear to partly cloudy
conditions with west to northwesterly surface winds were common.
This afternoon...the mid level frontal boundary is expected to
push southeast into the CWA as the Arizona low becomes more of an
open wave as it shifts east and the Kansas low continues to
weaken. Latest HRRR runs try to develop some precip along this
boundary over Northeast Oklahoma this afternoon. For now will
continue with the current small pops northwest of Interstate
44...as the drier low level air over the region could hinder
precip reaching the ground. The better precip chances continue to
look to be tonight into Monday as the Arizona upper low moves into
the Southern Plains.
Ahead of the mid level boundary...Partly cloudy skies west to
mostly clear skies east will allow for temps to warm into the
60s-lower 70s from northwest to southeast over the CWA. As the
boundary moves into the region...cloud cover should begin to
increase with mostly cloudy conditions over the CWA expected this
evening. Also today...west to northwesterly winds 5 to 15 mph should
continue across the CWA.
Morning update will be to add minor tweaks to the afternoon
temp/pop/dewpoint/wind grinds and adjust timing of increasing sky
grids. Otherwise...current forecasts seems to be in good shape at
this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 47 65 45 72 / 30 10 0 10
FSM 52 69 47 71 / 40 10 10 0
MLC 50 66 44 71 / 30 10 0 10
BVO 46 65 40 72 / 30 10 0 10
FYV 47 63 39 67 / 30 10 10 10
BYV 48 63 42 67 / 20 20 10 10
MKO 48 65 44 71 / 30 10 0 0
MIO 47 63 41 70 / 20 20 10 0
F10 48 65 44 71 / 30 10 0 0
HHW 54 70 46 72 / 40 10 0 10
&&
.TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...20
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1256 PM CDT SUN MAY 1 2016
.DISCUSSION...
UPDATED FOR AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 1106 AM CDT SUN MAY 1 2016/
UPDATE...
CURRENTLY...SHOWERS AND THUNDERSTORMS CONTINUE TO SKIRT MONROE
COUNTY MISSISSIPPI. THESE SHOWERS ARE MOVING ALONG AN OLD OUTFLOW
BOUNDARY. EXPECT THIS TREND TO CONTINUE INTO THE AFTERNOON HOURS.
MEANWHILE...THE COLD FRONT CURRENTLY STRETCHES FROM NEAR PARIS
TENNESSEE TO NEAR STUGGART ARKANSAS. LATEST HRRR SHOWS DEVELOPMENT
OF THUNDERSTORMS ALONG AND AHEAD OF THE FRONT THIS AFTERNOON.
LATEST KNQA RADAR SHOWS THE FIRST SHOWER MAY BEGINNING TO GO UP
OVER LEE COUNTY ARKANSAS. WILL UPDATE TO RAISE POPS IN THE
VICINITY OF THE FRONT. THE AIRMASS IS PRETTY UNSTABLE AHEAD OF THE
FRONT AND WOULD NOT BE SURPRISED TO SEE A STRONG OR SEVERE STORM
AS WELL.
KRM
DISCUSSION... /ISSUED 404 AM CDT SUN MAY 1 2016/
THERE IS SOME PATCHY FOG ACROSS THE MIDSOUTH...BUT SO FAR WE HAVE
NOT SEEN ANYTHING THAT WARRANTS THE NEED FOR AN ADVISORY. DEW
POINT DEPRESSIONS ARE SMALLEST NEAR THE TENNESSEE RIVER AND
KENTUCKY STATE LINE. WILL CONTINUE TO MONITOR CONDITIONS AND
UPDATE LATER THIS MORNING IF NEEDED. TEMPERATURES ARE MOSTLY IN
THE MIDDLE 60S THIS MORNING...AND EXPECTED TO FALL INTO THE LOW
60S BY SUNRISE. THERE WERE A FEW THUNDERSTORMS ON RADAR EARLIER IN
THE NIGHT...BUT AS OF 3 AM...ONLY ISOLATED SHOWERS REMAIN. SHORT
TERM HIGH RESOLUTION GUIDANCE...WHICH HAS PERFORMED WELL FOR THE
LAST FEW DAYS...SUGGESTS THE WEAKENING TREND WILL CONTINUE THROUGH
SUNRISE.
A COLD FRONT IS MOVING ACROSS THE MIDSOUTH. IT IS CURRENTLY
APPROACHING KENNETT MISSOURI AND WYNNE ARKANSAS. THIS FEATURE IS
EXPECTED TO STALL LATER THIS EVENING OR OVERNIGHT ACROSS NORTH
MISSISSIPPI INTO CENTRAL TENNESSEE. AHEAD OF THE FRONT MAINLY...IN
WEST TENNESSEE AND NORTH MISSISSIPPI SHOWERS AND THUNDERSTORMS
MAY REDEVELOP THIS AFTERNOON. STRONG OR SEVERE THUNDERSTORMS ARE
NOT EXPECTED. COVERAGE MAY BE LIMITED UNTIL LATE AFTERNOON WHEN A
MID LEVEL TROUGH WILL APPROACH THE MISSISSIPPI RIVER VALLEY
PROVIDING A BIT MORE UPPER LEVEL SUPPORT. THE HIGHEST RAIN CHANCES
WILL LIKELY RETURN TONIGHT INTO EARLY MONDAY...ESPECIALLY IN NORTH
MISSISSIPPI AS THE TROUGH CONTINUES EAST. MONDAY SHOULD BE OUR
LAST DAY OF SHOWERS AND THUNDERSTORMS. SEVERE STORMS ARE NOT
EXPECTED.
SYNOPTICALLY...WE WILL SEE A BLOCKING PATTERN SET UP EARLY NEXT
WEEK AND REMAIN IN PLACE FOR SEVERAL DAYS....POSSIBLY INTO NEXT
WEEKEND. AS A RESULT...EXPECT BENIGN WEATHER. CLEAR TO PARTLY
CLOUDY SKIES AND MILD TEMPERATURES ARE EXPECTED FOR THE UPCOMING
WORK WEEK.
TEMPERATURES WILL TURN COOLER EARLY THIS WEEK. HIGHS MONDAY
SHOULD TOP OUT ON THE LOW 70S...AND MAY NOT CLIMB OUT OF THE 60S
IN DURING THE MIDDLE PART OF THE WORK WEEK. THE COOLEST
TEMPERATURES OVER THE NEXT WEEK OR SO SHOULD OCCUR WEDNESDAY OR
THURSDAY MORNING WHEN SOME LOCATIONS COULD DIP INTO THE MIDDLE
40S. TEMPERATURES WILL TREND SLIGHTLY WARMER FRIDAY INTO NEXT
WEEKEND.
30
&&
.AVIATION...
A COLD FRONT IS SITUATED FROM KUCY TO KPBF. KJBR IS WEST OF THE
FRONT SO EXPECT VFR CONDS THERE WITH LIGHT NW WINDS THROUGH THE
OVERNIGHT. EXPECT SCATTERED SHRAS AND TSRAS TO DEVELOP AHEAD OF
THIS FRONT. ADDED VCTS TO KMEM/KMKL/KTUP FOR THIS AFTERNOON INTO
EARLY THIS EVENING. VFR CONDS EXPECTED OVERNIGHT WITH LIGHT AND
VARIABLE WINDS BECOMING LIGHT NORTHWEST LATE. CONFIDENCE TOWARD
THE END OF THE PERIOD IS LOW. ATTM EXPECT AN AREA OF SHRAS WITH
EMBEDDED TSRAS TO MOVE NE INTO THE MIDSOUTH MONDAY MORNING AS LOW
PRESSURE TRACKS ALONG THE VERY SLOW MOVING COLD FRONT.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1227 PM CDT SUN MAY 1 2016
.UPDATE...
COOL AND DRY AIR CONTINUES TO FILTER SOUTH ACROSS MUCH OF THE CWA
WITH THE FRONT SOUTH OF OUR CENTRAL COUNTIES. SOME LINGERING
MOISTURE JUST ABOVE THE SHALLOW FRONTAL INVERSION WILL PERSIST
LATE TODAY AND WITH DAYTIME HEATING...ISOLATED SHOWERS AND STORMS
MAY STILL DEVELOP FROM TEMPLE TO PALESTINE. CONFIDENCE IS NOT HIGH
FOR ACTUAL CONVECTION TO DEVELOP THIS FAR NORTH AND HAVE LOWERED
LOWERED POPS DOWN INTO THE SLIGHT CHANCE CATEGORY.
THE TTU WRF CONTINUES TO SHOW LARGE-SCALE ASCENT OVER NM/W TX
APPROACHING OUR FAR NW COUNTIES THROUGH 00Z WITH SOME SCATTERED
SHOWER DEVELOPMENT AFTER 21Z. THE HRRR AND NAM12 SOLUTIONS DON/T
AGREE AND WILL FOLLOW THESE MODELS CONSIDERING HOW DRY THE LOW
LEVEL AIRMASS IS. CANNOT RULE OUT SOME REPORTS OF VIRGA OVER THE
NORTHWEST COUNTIES LATE THIS AFTERNOON...BUT NOTHING WITH REGARD
TO MEASURABLE RAINFALL IS EXPECTED.
WE/LL CONTINUE TO SEE THE LARGE-SCALE ASCENT SPREAD OVER THE AREA
TONIGHT...THEN LINGER OVER MAINLY THE SOUTHERN CWA MONDAY MORNING.
MODELS ARE LESS AGGRESSIVE ON CONVECTIVE COVERAGE AND WE/LL ONLY
ADVERTISE CHANCE POPS VERSUS A LIKELY MENTION. BETTER FORCING AND
RAIN CHANCES SHOULD EXIT THE AREA MONDAY AFTERNOON...AS THE UPPER
DISTURBANCE DEPARTS THE AREA.
THOUGH TEMPERATURES HAVE BEEN SLOW TO WARM EARLY TODAY WITH THE
CAA...PLENTIFUL SUNSHINE SHOULD ALLOW SEVERAL MORE HOURS OF
WARMING AND INTO THE 70S BY LATE AFTERNOON WITH GOOD INSOLATION
SEEN THIS TIME OF THE YEAR.
05/
&&
.AVIATION...
/ISSUED 1125 AM CDT SUN MAY 1 2016/
A WEAKENING UPPER LOW OVER THE DESERT SOUTHWEST WILL SEND A
SHORTWAVE EAST ACROSS THE SOUTHERN PLAINS TONIGHT. NORTH AND
CENTRAL TEXAS CURRENTLY RESIDE ON THE NORTH SIDE OF A COLD
FRONT...WHICH LEAVES US WITH LITTLE IN THE WAY OF AVAILABLE
MOISTURE AS THE SYSTEM PASSES OVERHEAD. STILL...THERE SHOULD BE
ENOUGH LIFT...AND SOME MEAGER LEVELS OF ELEVATED INSTABILITY...TO
GENERATE SCATTERED SHOWERS A A FEW ISOLATED STORMS DURING THE
OVERNIGHT HOURS. WITH SPARSE COVERAGE EXPECTED...WE WILL CONTINUE
TO INDICATE VCSH FROM LATE THIS EVENING TO EARLY MONDAY MORNING AT
ALL TAF SITES. IF FUTURE MODELS COME IN MORE AGGRESSIVE WITH
DEVELOPMENT...WE WOULD LIKELY NEED TO INDICATE TS DURING A BRIEF
PORTION OF THE TAF FOR THE OVERNIGHT TIME PERIOD.
OTHERWISE...SURFACE WINDS SHOULD REMAIN OUT OF THE NORTH FOR THE
DURATION OF THE FORECAST.
30
&&
.PREV DISCUSSION... /ISSUED 351 AM CDT SUN MAY 1 2016/
A VERY SUBTLE SHORTWAVE RIDGE WILL BUILD EAST OF THE REGION TODAY
WHILE AN UPPER LEVEL LOW APPROACHES FROM THE DESERT SOUTHWEST.
LARGE SCALE LIFT WILL INCREASE ACROSS NORTH AND CENTRAL TEXAS
THROUGH TONIGHT AS THE UPPER LOW OPENS UP AND LIFTS TOWARD THE
CENTRAL PLAINS. THE BEST SURFACE BASED INSTABILITY TODAY WILL
RESIDE SOUTH OF THE FORECAST AREA IN CENTRAL AND SOUTH TEXAS.
HOWEVER...MODELS DO INDICATE THAT THE SOUTHEAST ZONES WILL SEE
SOME SURFACE BASED CAPE BETWEEN 1000 AND 1500 J/KG BY LATE THIS
AFTERNOON...SO WILL KEEP SOME CHANCE POPS MENTIONED. THE SEVERE
POTENTIAL APPEARS FAIRLY LOW OVERALL...BUT IF ANY STORM WERE TO
APPROACH SEVERE LIMITS IT WOULD BE IN THE EXTREME SOUTHEAST LATE
THIS AFTERNOON.
RAIN AND THUNDERSTORM CHANCES WILL INCREASE AREA WIDE TONIGHT WITH
INCREASING LARGE SCALE UPWARD VERTICAL MOTION. HOWEVER...THE
POTENTIAL FOR SURFACE BASED STORMS WILL DECREASE OVERNIGHT AND
MONDAY AS A REINFORCEMENT OF DRY AND COOL AIR FILTERS IN FROM THE
NORTH WITH THE PASSAGE OF THE UPPER TROUGH AXIS. THERE WILL BE
ENOUGH MID LEVEL INSTABILITY FOR ELEVATED THUNDERSTORMS WITH
LIGHTNING BEING THE PRIMARY HAZARD.
PRECIPITATION CHANCES WILL DECREASE FROM NORTH TO SOUTH THROUGH
THE AFTERNOON MONDAY AS THE UPPER LOW TRANSLATES SLOWLY NORTHEAST
AS DEPTH OF THE DRY/COOL AIR INCREASES. THE COLD AIR ADVECTION
COUPLED WITH EXTENSIVE CLOUD COVER MONDAY WILL RESULT IN A COOL
DAY FOR EARLY MAY WITH HIGHS MAINLY IN THE MIDDLE 60S AND LOWER
70S.
TUESDAY THROUGH FRIDAY WILL BE DRY WITH A GRADUAL WARMING TREND AS
UPPER LEVEL HIGH PRESSURE AMPLIFIES OVER THE CENTRAL CONUS. HIGHS
WILL GENERALLY BE IN THE UPPER 70S AND LOWER 80S WITH LOWS MAINLY
IN THE 50S.
THE AMPLIFIED UPPER RIDGE AXIS WILL TRANSLATE EAST ON SATURDAY
WHILE A STRONG UPPER LOW APPROACHES FROM THE WESTERN UNITED
STATES. A FEW SHOWERS AND STORMS WILL BE POSSIBLE ACROSS THE
WESTERN ZONES SATURDAY AFTERNOON/SATURDAY NIGHT WITH BETTER STORM
CHANCES EXPECTED BY NEXT SUNDAY. HOWEVER...THERE IS A VERY GOOD
CHANCE THAT THE UPPER LOW COULD REMAIN CUT OFF WEST OF THE REGION
FOR SEVERAL DAYS WHICH WOULD KEEP THE BEST PRECIPITATION CHANCES
WEST OF NORTH AND CENTRAL TEXAS AS WE HEAD INTO THE SECOND WEEK OF
MAY.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH 75 55 71 52 74 / 5 40 20 5 5
WACO 76 56 71 52 74 / 10 50 40 5 5
PARIS 75 53 69 51 71 / 5 40 20 5 5
DENTON 72 51 70 49 73 / 5 40 20 5 5
MCKINNEY 74 53 70 50 72 / 5 40 20 5 5
DALLAS 76 56 72 53 74 / 5 40 20 5 5
TERRELL 77 56 72 52 73 / 10 40 30 5 5
CORSICANA 78 58 73 53 73 / 10 50 40 5 5
TEMPLE 78 58 69 53 73 / 10 50 40 10 5
MINERAL WELLS 72 49 68 48 74 / 10 40 20 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
30/05
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
335 PM CDT SUN MAY 1 2016
.TONIGHT AND MONDAY...FORECAST CONFIDENCE...MEDIUM
MODELS CONTINUE TO STRUGGLE A BIT WITH RAIN CHANCES LATER THIS
AFTERNOON AND INTO THE EVENING. THE UPPER WAVE IS PROGGED TO COME
THROUGH THIS EVENING...WITH CURRENT RADAR REFLECTIVITIES EXPANDING
IN THE VICINITY OF THE SHORTWAVE. THE NAM AND GFS KEEP MUCH OF THE
PRECIP TO THE SOUTH OF THE WI/IL BORDER...WHILE THE ECMWF AND
CANADIAN ARE FARTHER NORTH AND WETTER. MESOSCALE MODELS SEEM TO
AGREE WITH THE WETTER SOLUTIONS...SO KEPT LIKELY GOING IN THE FAR
SOUTH. MIGHT NEED TO BUMP POPS UP THOUGH OVER THE NEXT COUPLE HOURS
GIVEN LATEST RADAR AND HRRR TRENDS. RAIN SHOULD EXIT THE SOUTHEAST
BY MIDNIGHT OR SO...WITH CLEARING SKIES FROM NORTH TO SOUTH BEHIND
THE DEPARTING SYSTEM.
SHOULD BE A PLEASANT DAY MONDAY WITH SUNSHINE TO START THE
DAY...THOUGH WILL SEE A GOOD AMOUNT OF AFTERNOON CUMULUS AWAY FROM
THE LAKE. SHOULD SEE TEMPS RETURN TO AROUND NORMAL...EXCEPT FOR
COOLER NEAR LAKE MICHIGAN.
.MONDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
HIGH PRESSURE NUDGES INTO THE REGION FOR MONDAY NIGHT AS MID LEVEL
TROUGH DEPARTS SOUTHERN WI. TEMPERATURES ON TUESDAY LOOK MILD WITH
SOME SUN. THEN PRECIP LOOKS LIKELY TUESDAY NIGHT ALONG A SOUTHWARD
MOVING COLD FRONT. THERE IS GOOD SYNOPTIC FORCING FROM A STRONG
VORTICITY MAXIMUM WITHIN A DEEP GREAT LAKES TROUGH AND UPPER
DIVERGENCE FROM THE LEFT EXIT REGION OF A 90KT JET. THERE IS SOME
UNCERTAINTY WITH THUNDERSTORM CHANCES. THE NAM IS THE MOST
AGGRESSIVE WITH CAPE SHOWING A FEW HUNDRED J/KG WHILE OTHER
MODELS SHOW MUCH LESS.
TEMPERATURES WILL BE COOLER ON WEDNESDAY BEHIND THE FRONT AND
BRISK NORTH WINDS. THE NAM IS AN OUTLIER SHOWING PRECIP LINGERING
THROUGH WEDNESDAY WITH THE UPPER LOW REMAINING OVER SOUTHEAST WI
SO HAVE LOW POPS THROUGH THE DAY.
.WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE...HIGH
HIGH PRESSURE DOMINATES WEDNESDAY NIGHT THROUGH FRIDAY WITH A MID
LEVEL RIDGE. WEDNESDAY NIGHT WILL BE CHILLY THEN A THERMAL RIDGE
SETTLES IN BRINGING MUCH WARMER TEMPERATURES. THE CANADIAN AND GFS
SHOW SOME PRECIP FRIDAY NIGHT INTO SATURDAY MORNING BUT FORCING
IS WEAK SO KEPT FORECAST DRY.
SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM
THERE IS A BETTER CHANCE FOR PRECIP SOMETIME SATURDAY AFTERNOON TO
SUNDAY ALONG A SLOW MOVING FRONTAL BOUNDARY STRETCHED WEST TO EAST
ACROSS SOUTHERN WI. ADDED A CHANCE OF THUNDER BUT INSTABILITY
DEPENDS ON THE TIMING OF THE FRONT. TEMPERATURES COOL SUNDAY BEHIND
THE FRONT. THE MID LEVEL RIDGE BREAKS DOWN SUNDAY AS AN UPPER
LOW DRIFTS TOWARD THE REGION.
&&
.AVIATION/00Z TAFS/...
A LARGE AREA OF CLEARING CONTINUES TO EXPAND THIS AFTERNOON...THOUGH
NOW SEEING SOME LOWER CLOUDS ADVECTING BACK IN FROM THE EAST. STILL
SEEMS THE SOUTH HALF OF THE FORECAST AREA WILL BE IN OR NEAR MVFR
CONDITIONS INTO THE EVENING...WITH MAINLY VFR NORTH. SHOULD BE VFR
ACROSS SOUTHERN WISCONSIN BY EARLY IN THE NIGHT...WITH VFR
PERSISTING THROUGH MONDAY AS HIGH PRESSURE BUILDS IN.
STILL LOOKS LIKE SOME RAIN IN AT LEAST SOUTHERN PORTIONS OF THE
FORECAST AREA LATER THIS AFTERNOON AND INTO THE EVENING. SHOULD SEE
RAIN WIND DOWN IN THE SOUTHEAST BY MIDNIGHT OR SHORTLY THEREAFTER.
DRY WEATHER IS EXPECTED MONDAY AS HIGH PRESSURE BUILDS IN.
&&
.MARINE...
WIND GUSTS ARE STILL NEAR SMALL CRAFT ADVISORY LEVELS THIS
AFTERNOON...SO WILL KEEP THE ADVISORY GOING FOR NOW. DID CHANGE THE
END OF THE SOUTHERN ZONE ADVISORY TO 00Z...AS WINDS SHOULD BE EASING
BY THEN.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...DDV
MONDAY NIGHT THROUGH SUNDAY...MARQUARDT