Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/20/14
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
527 PM PDT MON MAY 19 2014
.SYNOPSIS...COOLER THAN NORMAL TEMPERATURES ARE FORECAST EARLY THIS
WEEK AS AN UPPER LEVEL SYSTEM MOVES ACROSS NORTHERN CALIFORNIA. A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS EXISTS LATE THIS
AFTERNOON AND AGAIN TUESDAY AFTERNOON BUT MAINLY OVER THE REMOTE
HILLS OF THE BAY AREA AND MONTEREY BAY REGION. DRY CONDITIONS WILL
RETURN ALONG WITH A WARMING TREND FOR THE SECOND HALF OF THE WEEK
AND INTO THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ALONG THE
WEST COAST.
&&
.DISCUSSION...AS OF 2:01 PM PDT MONDAY...COLD CORE UPPER LOW IS
NOW LOCATED WEST OF CAPE MENDOCINO WITH SHOWERS AND T-STORMS
FIRING OVER NORTHEAST CALIFORNIA AND MOST RECENTLY AS CLOSE AS
COLUSA AND GLENN COUNTIES. FOLLOWING THE RAP MODEL THE UPPER LOW
WILL QUICKLY MAKE A BEELINE FOR THE NORTH BAY LATER THIS EVENING
AND OVERNIGHT. THEREFORE THE BEST CHANCE OF ANY SHOWER OR ISOLATED
T-STORMS WILL BE OVER THE NORTH BAY HILLS...BEST CHANCE OVER
NORTHERN SONOMA AND NAPA COUNTY HILLS.
THE LATEST SOLUTIONS BRING THE LOW INTO THE CENTRAL VALLEY BY
TUESDAY MORNING WITH SOME NW ONSHORE SHOWERS POSSIBLE ALONG THE
BIG SUR COAST EARLY TUESDAY. OTHERWISE EXPECT A PARTLY CLOUDY AND
COOL DAY ON TUESDAY WITH SOME SHOWERS AND T-STORMS POSSIBLE BY
AFTERNOON...AGAIN MOST LIKELY OVER THE HIGHER TERRAIN/REMOTE AREAS
ROUGHLY RUNNING FROM NAPA COUNTY SOUTHWARD INTO THE DIABLO RANGE
AND OVER FAR EASTERN SANTA CLARA AND SAN BENITO COUNTIES. THE
COOLER TEMPS AND HIGHER HUMIDITY WILL MITIGATE MOST FIRE WEATHER
CONCERNS. FOR MOST FOLKS THE WEATHER WILL FEATURE PARTY CLOUDY AND
SEASONABLE TEMPS.
BY WEDS THE LOW WILL EJECT INTO NEVADA WITH ISOLATED CHANCES ONLY
REMAINING OVER THE HIGHER TERRAIN OF SAN BENITO AND FAR SOUTHEAST
MONTEREY COUNTY.
HIGH PRESSURE WILL BEGIN TO NOSE OVER THE REGION THURSDAY AND INTO
THE UPCOMING WEEKEND WITH A NOTED WARMING TREND AS 850 MB TEMPS
WARM TO AROUND 21-23 CELSIUS INLAND BY SUNDAY AND MEMORIAL DAY.
&&
.AVIATION...AS OF 5:00 PM PDT MONDAY...SCATTERED MID-LEVEL CLOUDS
PERSIST ACROSS THE REGION WITH CONDITIONS EXPECTED TO GRADUALLY
IMPROVE AS THE EVENING PROGRESSES. MAINLY HIGH CLOUDS EXPECTED
TONIGHT WITH A FEW PATCHES OF MVFR CIGS EXPECTED AFTER MIDNIGHT
TONIGHT AND ANTICIPATED TO SCATTER OUT EARLY TUESDAY MORNING
BETWEEN 15-18Z. MODERATE TO LIGHT WEST WINDS WILL CONTINUE
THROUGH THE PERIOD. MODERATE CONFIDENCE.
VICINITY OF KSFO...VFR CONDITIONS WITH LOCALLY GUSTY WEST WINDS
TO AROUND 30 KT WILL CONTINUE THROUGH THIS EVENING THEN EASE TO
AROUND 10-15 KT OVERNIGHT. IFR CIGS TO RETURN AFTER 08Z OVER KOAK
WITH CLEARING ANTICIPATED AROUND 16Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL CONTINUE THROUGH
THIS EVENING WITH MVFR CIGS EXPECTED TO RETURN AFTER 05Z AND 09Z
OVER KSNS AND KMRY RESPECTIVELY. LOCALLY GUSTY WEST WINDS TO
AROUND 25 KT WILL DIMINISH AFTER SUNSET THIS EVENING.
&&
.MARINE...AS OF 03:45 AM PDT MONDAY...SURFACE HIGH PRESSURE WILL
DOMINATE THE EASTERN PACIFIC THROUGH THE FORECAST...RESULTING IN
NORTHWEST WINDS OVER THE WATERS. WINDS WILL INCREASE WEDNESDAY
INTO THE WEEKEND GENERATING STEEP FRESH SWELLS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...SCA...PT ARENA TO PT REYES 10-60 NM FROM 2 AM
SCA...PT ARENA TO PT REYES 0-10 NM FROM 6 AM
SCA...PT REYES TO PIGEON PT 10-60 NM FROM 6 AM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 6 AM
SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 9 PM
SCA...SF BAY SOUTH OF THE BAY BRIDGE UNTIL 9 PM
SCA...MONTEREY BAY UNTIL 9 PM
&&
$$
PUBLIC FORECAST: RWW
AVIATION: CW
MARINE: RILEY
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SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATE
NWS LOS ANGELES/OXNARD CA
525 PM PDT MON MAY 19 2014
...NEW AVIATION DISCUSSION...
.SYNOPSIS...
A LOW SYSTEM WILL BRING BELOW NORMAL TEMPERATURES...POSSIBLE
PRECIPITATION...ESPECIALLY MOUNTAIN AREAS...AND BREEZY WINDS THROUGH
THURSDAY. THE LOW WILL SLOWLY MOVE EAST ON FRIDAY WITH TEMPERATURES
FORECAST TO EXCEED NORMAL. A HIGH WILL BULGE IN SATURDAY FOR AN
ADDITIONAL WARMING OF TEMPERATURES INTO EARLY NEXT WEEK.
&&
.SHORT TERM (TONIGHT-THU)...
IMPACTFUL WEATHER WILL BE MINIMAL THROUGH DAY7. GUSTY NORTHWEST
WINDS WILL GENERATE GALE FORCE WINDS FOR THE OUTER COASTAL WATERS
AND A WEAK SUNDOWNER IS EXPECTED ACROSS SANTA BARBARA COUNTY
TONIGHT. HRRR HIGH RESOLUTION MODEL DATA SHOWS GUSTS 38KTS BETWEEN
GOLETA AND GAVIOTA THIS EVENING. OTHER WEATHER PROBLEM OF THE NIGHT
IS THE DEPTH OF THE MARINE LAYER AND EXTENT OF CLOUD COVER BY
TUESDAY MORNING. NAM BUFR SOUNDINGS INDICATE WELL ABOVE 5000 FEET
AND BOUNDARY LAYER HUMIDITY GOES ABOVE 90 PERCENT ACROSS MOST OF THE
AREA BY 12Z. HAVE PUSHED CLOUDS WELL INTO THE SOUTH SLOPES OF THE
MOUNTAINS AND ACROSS MOST OF SLO COUNTY WITH THE ADDITION OF DRIZZLE
TOMORROW MORNING.
LOW PRESSURE WAS DEEPENING RAPIDLY OFF THE NORTHERN CA COAST THIS
AFTERNOON AND WILL SWING INTO THE SACRAMENTO VALLEY BY 12Z
TUESDAY...THEN EASTWARD INTO NV THROUGH WEDNESDAY. A SECONDARY
DISTURBANCE WILL ROTATE AROUND THE LOW DUMBBELLING INTO ANOTHER LOW
ACROSS SOUTHERN CA ON THURSDAY. THERE IS MINIMAL MOISTURE CONTENT
WITH THIS SYSTEM BUT IT IS ALREADY GENERATING THUNDERSTORMS ACROSS
THE NORTHERN SIERRAS. AS THIS SYSTEM ROTATES SOUTH AND EAST THROUGH
THURSDAY EXPECT TO SEE TEMPERATURES SLOWLY DECREASE DUE TO VARYING
AMOUNTS OF CLOUDS AND A SLIGHT CHANCE OF RAIN SHOWERS FOCUSED ON THE
HIGHER ELEVATIONS. WE WILL NEED TO KEEP AN EYE ON THE POTENTIAL FOR
CONVECTION WEDNESDAY AND THURSDAY AFTERNOONS FORMING OVER THE
SOUTHERN SIERRAS AND ACROSS THE SAN GABRIEL MOUNTAINS. INSTABILITY
PARAMETERS ARE INDICATING 33 DEGREE K-INDEX...NEGATIVE LIFTED
INDEX...AND UP TO 500 J/KG CAPE FOR THE MOUNTAINS. IF CELLS DEVELOP
STEERING WINDS OUT OF THE NORTH-NORTHWEST COULD PUSH ACTIVITY INTO
THE LOS ANGELES COUNTY VALLEYS OR FARTHER SOUTHWARD IF THEY CAN
MAINTAIN THEIR STRENGTH.
.LONG TERM (FRI-MON)...
MODEL CONSENSUS THAT THE UPPER LOW WILL SHIFT TO THE AZ/MEXICO
BORDER ON FRIDAY AS THE TROUGH AXIS AND BULK OF ANY MOISTURE WILL BE
MAINLY EAST OF OUR AREA. LEFT A TOKEN SLIGHT CHANCE OF SHOWERS FOR
THE EASTERN SAN GABRIELS ON FRIDAY...OTHERWISE DRY WITH A WARMING
TREND. A HIGH PRESSURE RIDGE WILL BUILD INTO SOUTHWEST CA THROUGH
THE HOLIDAY WEEKEND WITH 585DM HEIGHTS BY SUNDAY. TEMPERATURES WILL
WARM BACK INTO THE 80S TO LOWER 90S ACROSS VALLEY AREAS. GFS AND GEM
MODELS THEN BRING ANOTHER LOW PRESSURE SYSTEM TO THE PACIFIC
NORTHWEST COAST ON MONDAY LOWERING HEIGHTS AND REDUCING TEMPERATURES
OVER CA. HOWEVER...THE ECM CONTINUES TO HOLD ONTO THE RIDGE THROUGH
MOST OF NEXT WEEK. FOR NOW WILL KEEP TEMPERATURES JUST AS WARM FOR
MONDAY UNTIL WE CAN GET BETTER MODEL AGREEMENT ON WHETHER THE RIDGE
WILL BREAKDOWN OR NOT EARLY NEXT WEEK.
&&
.AVIATION...20/0020Z...GENERALLY HI CONFIDENCE IN THE 00Z TAFS. LOW
CLOUDS AND MVFR CIGS SHOULD DEVELOP AT MOST OF THE COASTAL AND VLY
AIRFIELDS LATER THIS EVENING TO LATE TONIGHT THEN IMPROVE TO VFR
CIGS BY EARLY TUE MORNING FOR THE MOST PART BEFORE SCATTERING OUT BY
LATE TUE MORNING OR EARLY TUE AFTERNOON. SOME OF THE TIMINGS OF THE
LOW CLOUDS MAY BE OFF SLIGHTLY BUT THERE IS HI CONFIDENCE THE LOW
CLOUDS WILL DEVELOP. GUSTY W TO NW AFTERNOON AND EVENING WINDS WILL
AFFECT MOST COASTAL AIRFIELDS ALONG WITH KPRB...KWJF AND KPMD THRU
TUE. LOW LEVEL WIND SHEAR WILL BE POSSIBLE THIS EVENING AT KSBA DUE
TO GUSTY N CANYON WINDS IN THE VICINITY.
KLAX...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND MVFR
CIGS WILL DEVELOP BY 06Z THEN IMPROVE TO VFR CIGS BY 10Z BEFORE
SCATTERING OUT BY 21Z. VFR CONDITIONS WILL AFFECT THE AIRFIELD
TUE AFTERNOON AND EVENING. THE TIMING OF THE LOW CLOUDS MAY BE OFF
AN HOUR OR SO BUT THERE IS HI CONFIDENCE THE LOW CLOUDS WILL
DEVELOP. GUSTY W WINDS CAN BE EXPECTED EARLY THIS EVENING AND AGAIN
LATE TUE MORNING THRU THE EARLY EVENING.
KBUR...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND MVFR
CIGS WILL DEVELOP BY 08Z THEN IMPROVE TO VFR CIGS BY 12Z BEFORE
SCATTERING OUT BY 21Z. VFR CONDITIONS WILL AFFECT THE AIRFIELD THRU
THE REMAINDER OF TUE AFTERNOON. THE TIMING OF THE LOW CLOUDS
MAY BE OFF AN HOUR OR SO BUT THERE IS HI CONFIDENCE THE LOW CLOUDS
WILL DEVELOP.
&&
.MARINE...19/300 PM.
THE INNER WATERS ARE LIKELY TO EXPERIENCE SMALL CRAFT ADVISORY LEVEL
WINDS THROUGH TONIGHT THAT WILL AFFECT THE WESTERN SANTA BARBARA
CHANNEL...MAINLY WEST OF SANTA CRUZ ISLAND AND WATERS WEST OF SANTA
CATALINA ISLAND. GALE WARNINGS REMAIN FOR PZZ673 AND PZZ676 WHERE
THE STRONGEST WINDS WILL OCCUR THROUGH LATE TONIGHT. A SMALL CRAFT
ADVISORY ALSO REMAINS IN EFFECT FOR PZ645 AND PZ670 FOR WINDS
GUSTING TO AROUND 30 KNOTS.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...BOLDT
AVIATION...SIRARD
MARINE...SWEET
SYNOPSIS...SETO
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1109 AM MDT SUN MAY 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM MDT SUN MAY 18 2014
CURRENTLY...LATEST SATELLITE IMAGERY AND H5 RUC ANALYSIS INDICATES
GENERAL WESTERLY FLOW ACROSS THE STATE...WITH A GOOD AMOUNT OF MID
TO HIGH LEVEL CLOUDINESS STREAMING ACROSS COLORADO. THIS HAS KEPT
TEMPS SOMEWHAT MILD AS OF 4 AM...WITH READINGS IN THE 40S TO LOWER
50S.
TODAY AND TONIGHT...MODELS INDICATE THAT THE UPPER LOW OVER THE
PACIFIC NW WILL DROP TO THE SOUTH OVER THE NEXT 24 HRS...PUSHING THE
UPPER FLOW ACROSS THE 4 CORNERS TO A MORE SW DIRECTION. INCREASING
WARM AND DRY WINDS STREAMING INTO THE STATE WILL PRODUCE VERY DRY
CONDITIONS FOR THE FORECAST AREA...WITH CRITICAL FIRE WX CONDITIONS
A REAL CONCERN. THEREFORE...ONGOING RED FLAG FOR TODAY FOR
PORTIONS OF THE FORECAST AREA LOOKS GOOD...AS DOES THE WATCH FOR
TOMORROW. WHILE THE GFS KEEPS THE REGION PCPN FREE TODAY AND
TONIGHT...THE NAM HINTS AT SOME ISOLATED CONVECTION THIS AFTN OVER
THE PALMER DVD AND RAMPART RANGE. ONGOING GRIDS HAD ISOLATED POPS
THERE...SO OPTED TO MAINTAIN. OTHERWISE...DRY FOR THE REST OF THE
CWA. LOOK FOR MAX TEMPS TODAY IN THE 80S PUSHING 90 F...AND 70S
FOR THE HIGH VALLEYS. MOORE
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 412 AM MDT SUN MAY 18 2014
...CRITICAL FIRE WEATHER CONDITIONS CONTINUE THROUGH THE FIRST
PART OF THE WEEK WITH A TREND TOWARDS WETTER WEATHER BY NEXT
WEEKEND...
FORECAST MODELS STILL ADVERTISING THE SAME TREND WITH THE NEXT
CLOSED LOW DROPPING SOUTHWARD THROUGH CA INTO TUESDAY BEFORE
LIFTING IT NORTHWARD INTO NV/UT BY WEDNESDAY THEN DROPPING IT BACK
SOUTHWARD INTO AZ FOR FRIDAY THROUGH THE WEEKEND. THIS WILL MEAN
DRY SOUTHWEST FLOW WILL PERSIST THROUGH AT LEAST TUESDAY ACROSS
THE FORECAST AREA...WITH CRITICAL FIRE WEATHER CONDITIONS EXPECTED
TO RETURN FOR MOST OF THE LOWER ELEVATIONS ON MONDAY. BREEZY
SOUTHWEST WINDS WILL MEAN ABOVE NORMAL TEMPERATURES WITH WINDS
INITIALLY INCREASING OVER THE HIGHER ELEVATIONS FIRST...THEN
ACROSS THE SOUTHEAST PLAINS DURING THE AFTERNOON. PUEBLO AND
LOCATIONS TO THE LEE OF THE WETS MAY MIX OUT THE LATEST...BUT
OVERALL STILL LOOKS LIKE A 3 HOUR WINDOW FOR CRITICAL FIRE WEATHER
CONDITIONS WITH LOW RELATIVE HUMIDITY VALUES AND GUSTY WINDS.
CURRENT FIRE WEATHER WATCH FOR MONDAY STILL LOOKS ON TRACK.
ON TUESDAY...NAM BRINGS A SHALLOW FRONT INTO NORTHERN PORTIONS OF
THE FORECAST AREA DURING THE MORNING...THEN MIXES IT BACK
NORTHWARD DURING THE AFTERNOON. GFS KEEPS THIS BOUNDARY TO THE
NORTH. OVERALL...AIRMASS DRIES OUT DURING THE AFTERNOON WHICH
SHOULD KEEP THREAT FOR THUNDERSTORMS NIL...BUT DEPENDING ON HOW
QUICKLY THIS FRONT MIXES OUT WILL DETERMINE HOW MUCH OF THE
SOUTHEAST PLAINS MAY SEE A REPEAT OF CRITICAL FIRE WEATHER
CONDITIONS TUESDAY AFTERNOON. FOR NOW THIS LOOKS MOST LIKELY TO
OCCUR SOUTH OF THE ARKANSAS RIVER...AND FOR THE SAN LUIS
VALLEY...THOUGH GIVEN THE UNCERTAINTIES WILL HOLD OFF ON ISSUING
ANOTHER FIRE WEATHER WATCH AT THIS POINT.
FRONT MAY MAKE A STRONGER PUSH INTO THE FORECAST AREA TUESDAY
NIGHT AND WEDNESDAY...THOUGH MODELS DISAGREE ON THIS DETAIL. THE
GFS MIXES THE FRONT BACK NORTHWARD KEEPING ANY PRECIPITATION TO
THE NORTH OF THE FORECAST AREA ON WEDNESDAY...WHILE NAM12 AND
ECMWF SUGGESTS AT LEAST NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT MAY SEE SOME THREAT FOR THUNDERSTORMS ALONG THE FRONT AND
SOUTHWARD EXTENDING DRY LINE. IF ECMWF IS CORRECT...THIS COULD BE
THE FIRST DAY WITH THE POTENTIAL FOR HEAVY RAIN PRODUCING
THUNDERSTORMS TO HIT THE WALDO CANYON BURN SCAR...AS DEW POINTS IN
THE MID 40S YIELD CAPE VALUES OF AROUND 1000 J/KG. OF
COURSE...DRIER GFS HAS THIS AXIS OF HIGHER CAPES AND RESULTANT QPF IN
NORTHEAST COLORADO...SO TOO SOON TO SAY FOR SURE.
BY THE LATTER PART OF THE WORK WEEK...SOUTHERLY LOW LEVEL FLOW
AHEAD OF THE CLOSED LOW ACROSS THE DESERT SOUTHWEST WILL
EVENTUALLY ADVECT HIGHER DEW POINTS NORTHWARD INTO THE SOUTHEAST
PLAINS. MEANWHILE...SHORTWAVE ENERGY EJECTING TO THE NORTHEAST
AROUND THE EASTERN AND NORTHERN PERIPHERY OF THE CLOSED LOW WILL
BEGIN TO IMPACT THE REGION. THIS WILL BRING INCREASING CHANCES
FOR AFTERNOON SHOWERS AND THUNDERSTORMS INTO NEXT WEEKEND. DEEP
LAYER SHEARS ARE NOT THE BEST FOR SEVERE WEATHER LATE IN THE WEEK
THROUGH THE WEEKEND...0-6 KM SHEARS REMAIN AROUND 30 KTS OR LESS
WITH SOUTH TO SOUTHEAST LOW LEVEL FLOW BENEATH SOUTHWEST FLOW
ALOFT. HOWEVER...CAPES WILL BE COMING UP INTO THE 1000+ J/KG RANGE
DURING THE AFTERNOONS. SO WE COULD CERTAINLY SEE SOME HEAVY RAIN
PRODUCING THUNDERSTORMS WHICH WILL RAMP UP CONCERNS FOR FLASH
FLOODING ON AREA BURN SCARS...PARTICULARLY THOSE LOCATED ACROSS
THE SOUTHEAST MOUNTAINS. AND WITH ENOUGH CAPE...THERE COULD STILL BE
THE THREAT FOR HAIL...SOME OF WHICH COULD APPROACH OR EXCEED
SEVERE LIMITS DEPENDING ON AVAILABLE CAPE...OR IF LOW LEVEL WINDS
CAN BACK A LITTLE MORE OUT OF THE EAST INCREASING THE SHEAR.
NEXT SUNDAY MAY END UP BEING THE MORE ACTIVE DAY AS THE UPPER LOW
SLOWLY MIGRATES EASTWARD...SO OVERALL THE TREND POINTS TO A WETTER
MORE ACTIVE PERIOD. -KT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1051 AM MDT SUN MAY 18 2014
VFR CONDITIONS ARE EXPECTED AT KCOS...KPUB AND KALS FOR THE NEXT
24 HRS. AT KALS THIS AFTERNOON AND EARLY THIS EVENING...SHOULD SEE
WIND GUSTS AROUND 25 KTS FROM THE SW. KCOS MAY SEE SOUTHERLY WIND
GUSTS OF 20-25 KTS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING
FOR COZ224-227>237.
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ224-230-233.
&&
$$
SHORT TERM...MOORE
LONG TERM...KT
AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
500 AM MDT SUN MAY 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM MDT SUN MAY 18 2014
CURRENTLY...LATEST SATELLITE IMAGERY AND H5 RUC ANALYSIS INDICATES
GENERAL WESTERLY FLOW ACROSS THE STATE...WITH A GOOD AMOUNT OF MID
TO HIGH LEVEL CLOUDINESS STREAMING ACROSS COLORADO. THIS HAS KEPT
TEMPS SOMEWHAT MILD AS OF 4 AM...WITH READINGS IN THE 40S TO LOWER
50S.
TODAY AND TONIGHT...MODELS INDICATE THAT THE UPPER LOW OVER THE
PACIFIC NW WILL DROP TO THE SOUTH OVER THE NEXT 24 HRS...PUSHING THE
UPPER FLOW ACROSS THE 4 CORNERS TO A MORE SW DIRECTION. INCREASING
WARM AND DRY WINDS STREAMING INTO THE STATE WILL PRODUCE VERY DRY
CONDITIONS FOR THE FORECAST AREA...WITH CRITICAL FIRE WX CONDITIONS
A REAL CONCERN. THEREFORE...ONGOING RED FLAG FOR TODAY FOR
PORTIONS OF THE FORECAST AREA LOOKS GOOD...AS DOES THE WATCH FOR
TOMORROW. WHILE THE GFS KEEPS THE REGION PCPN FREE TODAY AND
TONIGHT...THE NAM HINTS AT SOME ISOLATED CONVECTION THIS AFTN OVER
THE PALMER DVD AND RAMPART RANGE. ONGOING GRIDS HAD ISOLATED POPS
THERE...SO OPTED TO MAINTAIN. OTHERWISE...DRY FOR THE REST OF THE
CWA. LOOK FOR MAX TEMPS TODAY IN THE 80S PUSHING 90 F...AND 70S
FOR THE HIGH VALLEYS. MOORE
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 412 AM MDT SUN MAY 18 2014
...CRITICAL FIRE WEATHER CONDITIONS CONTINUE THROUGH THE FIRST
PART OF THE WEEK WITH A TREND TOWARDS WETTER WEATHER BY NEXT
WEEKEND...
FORECAST MODELS STILL ADVERTISING THE SAME TREND WITH THE NEXT
CLOSED LOW DROPPING SOUTHWARD THROUGH CA INTO TUESDAY BEFORE
LIFTING IT NORTHWARD INTO NV/UT BY WEDNESDAY THEN DROPPING IT BACK
SOUTHWARD INTO AZ FOR FRIDAY THROUGH THE WEEKEND. THIS WILL MEAN
DRY SOUTHWEST FLOW WILL PERSIST THROUGH AT LEAST TUESDAY ACROSS
THE FORECAST AREA...WITH CRITICAL FIRE WEATHER CONDITIONS EXPECTED
TO RETURN FOR MOST OF THE LOWER ELEVATIONS ON MONDAY. BREEZY
SOUTHWEST WINDS WILL MEAN ABOVE NORMAL TEMPERATURES WITH WINDS
INITIALLY INCREASING OVER THE HIGHER ELEVATIONS FIRST...THEN
ACROSS THE SOUTHEAST PLAINS DURING THE AFTERNOON. PUEBLO AND
LOCATIONS TO THE LEE OF THE WETS MAY MIX OUT THE LATEST...BUT
OVERALL STILL LOOKS LIKE A 3 HOUR WINDOW FOR CRITICAL FIRE WEATHER
CONDITIONS WITH LOW RELATIVE HUMIDITY VALUES AND GUSTY WINDS.
CURRENT FIRE WEATHER WATCH FOR MONDAY STILL LOOKS ON TRACK.
ON TUESDAY...NAM BRINGS A SHALLOW FRONT INTO NORTHERN PORTIONS OF
THE FORECAST AREA DURING THE MORNING...THEN MIXES IT BACK
NORTHWARD DURING THE AFTERNOON. GFS KEEPS THIS BOUNDARY TO THE
NORTH. OVERALL...AIRMASS DRIES OUT DURING THE AFTERNOON WHICH
SHOULD KEEP THREAT FOR THUNDERSTORMS NIL...BUT DEPENDING ON HOW
QUICKLY THIS FRONT MIXES OUT WILL DETERMINE HOW MUCH OF THE
SOUTHEAST PLAINS MAY SEE A REPEAT OF CRITICAL FIRE WEATHER
CONDITIONS TUESDAY AFTERNOON. FOR NOW THIS LOOKS MOST LIKELY TO
OCCUR SOUTH OF THE ARKANSAS RIVER...AND FOR THE SAN LUIS
VALLEY...THOUGH GIVEN THE UNCERTAINTIES WILL HOLD OFF ON ISSUING
ANOTHER FIRE WEATHER WATCH AT THIS POINT.
FRONT MAY MAKE A STRONGER PUSH INTO THE FORECAST AREA TUESDAY
NIGHT AND WEDNESDAY...THOUGH MODELS DISAGREE ON THIS DETAIL. THE
GFS MIXES THE FRONT BACK NORTHWARD KEEPING ANY PRECIPITATION TO
THE NORTH OF THE FORECAST AREA ON WEDNESDAY...WHILE NAM12 AND
ECMWF SUGGESTS AT LEAST NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT MAY SEE SOME THREAT FOR THUNDERSTORMS ALONG THE FRONT AND
SOUTHWARD EXTENDING DRY LINE. IF ECMWF IS CORRECT...THIS COULD BE
THE FIRST DAY WITH THE POTENTIAL FOR HEAVY RAIN PRODUCING
THUNDERSTORMS TO HIT THE WALDO CANYON BURN SCAR...AS DEW POINTS IN
THE MID 40S YIELD CAPE VALUES OF AROUND 1000 J/KG. OF
COURSE...DRIER GFS HAS THIS AXIS OF HIGHER CAPES AND RESULTANT QPF IN
NORTHEAST COLORADO...SO TOO SOON TO SAY FOR SURE.
BY THE LATTER PART OF THE WORK WEEK...SOUTHERLY LOW LEVEL FLOW
AHEAD OF THE CLOSED LOW ACROSS THE DESERT SOUTHWEST WILL
EVENTUALLY ADVECT HIGHER DEW POINTS NORTHWARD INTO THE SOUTHEAST
PLAINS. MEANWHILE...SHORTWAVE ENERGY EJECTING TO THE NORTHEAST
AROUND THE EASTERN AND NORTHERN PERIPHERY OF THE CLOSED LOW WILL
BEGIN TO IMPACT THE REGION. THIS WILL BRING INCREASING CHANCES
FOR AFTERNOON SHOWERS AND THUNDERSTORMS INTO NEXT WEEKEND. DEEP
LAYER SHEARS ARE NOT THE BEST FOR SEVERE WEATHER LATE IN THE WEEK
THROUGH THE WEEKEND...0-6 KM SHEARS REMAIN AROUND 30 KTS OR LESS
WITH SOUTH TO SOUTHEAST LOW LEVEL FLOW BENEATH SOUTHWEST FLOW
ALOFT. HOWEVER...CAPES WILL BE COMING UP INTO THE 1000+ J/KG RANGE
DURING THE AFTERNOONS. SO WE COULD CERTAINLY SEE SOME HEAVY RAIN
PRODUCING THUNDERSTORMS WHICH WILL RAMP UP CONCERNS FOR FLASH
FLOODING ON AREA BURN SCARS...PARTICULARLY THOSE LOCATED ACROSS
THE SOUTHEAST MOUNTAINS. AND WITH ENOUGH CAPE...THERE COULD STILL BE
THE THREAT FOR HAIL...SOME OF WHICH COULD APPROACH OR EXCEED
SEVERE LIMITS DEPENDING ON AVAILABLE CAPE...OR IF LOW LEVEL WINDS
CAN BACK A LITTLE MORE OUT OF THE EAST INCREASING THE SHEAR.
NEXT SUNDAY MAY END UP BEING THE MORE ACTIVE DAY AS THE UPPER LOW
SLOWLY MIGRATES EASTWARD...SO OVERALL THE TREND POINTS TO A WETTER
MORE ACTIVE PERIOD. -KT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 412 AM MDT SUN MAY 18 2014
VFR CONDITIONS FOR THE REGION INCLUDING THE THREE MAIN TAF SITES OF
KCOS...KPUB AND KALS FOR THE NEXT 24 HRS. GUSTY SW WINDS 25-30 MPH
ARE EXPECTED TO DEVELOP AFTER 17Z AND LAST THROUGH 03Z .
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING
FOR COZ224-227>237.
RED FLAG WARNING FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
COZ224-230-233.
&&
$$
SHORT TERM...MOORE
LONG TERM...KT
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
342 PM EDT SUN MAY 18 2014
.SYNOPSIS...
HIGH PRESSURE CONTINUES TO BUILD IN THROUGH TUESDAY NIGHT AS A
WARM FRONT APPROACHES FROM THE SOUTHWEST. THIS FRONT MAY LIFT
THROUGH PART OF THE TRI-STATE AREA ON THURSDAY...WITH ITS PARENT
LOW PRESSURE SYSTEM TRACKING ACROSS THE AREA. AN UPPER LEVEL
DISTURBANCE WILL LINGER OVER THE AREA INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST HRRR RUN NOW BACKING OFF ON THE DEVELOPMENT OF ISO SHOWERS
LATE THIS AFTN...BUT WILL CONTINUE WITH MENTION OF ISO SHOWER
POTENTIAL THROUGH 00Z WITH JUST ENOUGH INSTABILITY REMAINING IN
PLACE. LATEST VIS SATELLITE SHOWING CU FIELD STREAMING IN FROM THE
NORTHWEST ALONG THE NW FLOW...SO VERY WELL COULD END UP WITH JUST
PARTLY SUNNY CONDITIONS WITH A SPRINKLE INTO THIS EVENING. THE
THREAT OF ANY LATE AFTN/EVENING SHOWERS THEN SUBSIDES WITH THE LOSS
OF DIURNAL HEATING AFTER 00Z.
CENTER OF HIGH PRESSURE POSITIONS ITSELF OVER THE OH RIVER
VALLEY...BUILDING GRADUALLY TO THE WEST INTO THE TRI STATE AREA
OVERNIGHT. THIS WILL RESULT IN DRY CONDITIONS INTO MONDAY MORNING.
ALOFT...THE AREA REMAINS POSITIONED UNDER UPPER LEVEL TROUGH...WITH
THE TROUGH AXIS SWINGING THROUGH BY LATE TONIGHT. PARTLY-MOSTLY
CLOUDY SKIES FIRST HALF OF THE NIGHT WITH SHORTWAVE ROUNDING THE
BASE OF THE TROUGH...WITH CLEARING THE SECOND HALF OF THE NIGHT AS
THE ENERGY PIVOTS TO THE EAST. CLEARING SKIES AND WEAKENING WINDS
WITH THE INFLUENCE OF THE HIGH DOMINATING WILL ALLOW FOR TEMPS TO
DROP A FEW DEGREES BELOW NORMAL TONIGHT. AS SUCH...SOME AREAS OF
INTERIOR NY AND CT COULD DROP INTO THE MID-UPPER 30S. WITH DEW PTS
HOVERING IN THE 30S AS WELL...COULD SEE SOME PATCHY FROST FORMATION
LATE TONIGHT OVER THESE AREAS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
ANOTHER DAY OF DRY CONDITIONS EXPECTED EARLY WITH THE POTENTIAL FOR
ISO PCPN FORMATION BY THE LATE AFTN. AT THE SURFACE...THE CENTER OF
THE HIGH REMAINS TO THE WEST...WITH LOW PRESSURE HOVERING
OFFSHORE AND A TROUGH SPLITTING THE REGION BY THE AFTERNOON WITH
DAY TIME HEATING. THE TROUGH ALOFT IS SLOW TO PUSH EAST DURING THE
DAY...WITH MODELS CONTINUING TO AGREE ON A CLOSED LOW FORMATION BY
MONDAY MORNING OVER THE NEW ENGLAND AREA. THIS LOW WILL CREEP TO
THE SOUTH AND EAST THROUGH THE AFTERNOON INTO TOMORROW
NIGHT...WITH ITS ASSOCIATED ENERGY/FORCING ASSISTING IN DEVELOPING
THE LATE AFTN SHOWERS AND POSSIBLE ISO TSTM. DOWNSLOPING RESULTING
FROM NW SYNOPTIC FLOW SHOULD HELP PUSH TEMPS TO NEAR NORMAL...IN
THE UPPER 60S TO LOWER 70S. WITH COLD POOL ALOFT SETTING UP...MORE
OVER EASTERN THAN WESTERN AREAS CLOSER TO THE CENTER OF THE CLOSED
LOW...SHOULD SEE STEEPENING MID LEVEL LAPSE RATES. THIS COMBINED
WITH INSTABILITY INCREASING WITH DIURNAL HEATING COULD TRIGGER ISO
SHOWERS BY LATE AFTN. CONTINUE THE MENTION OF ISO TSTM OVER CT AND
EASTERN LI DURING THIS TIME AS WELL CORRESPONDING WITH THE STEEPER
LAPSE RATES/BETTER INSTABILITY. DECENT HEATING AT THE SURFACE
SHOULD ALLOW FOR DEEP MIXING...RESULTING IN GUSTS BETWEEN 20 AND
30 KTS POSSIBLE AT THE SURFACE FOR THE AFTN. THE STRONGER FLOW
SHOULD HELP MINIMIZE THE EXTENT OF SEA BREEZE FORMATION...MAINLY
JUST AT THE IMMEDIATE SHORELINES.
LOSS OF DAY TIME HEATING ALONG WITH THE CLOSED LOW SLOWING INCHING
TO THE EAST AND TAKING THE BETTER FORCING WILL ONCE DIMINISH THE
THREAT OF PCPN BY 00Z TOMORROW EVENING. WEAK WAA SPREADING INTO
THE REGION WILL UP THE LOWS TOMORROW NIGHT A FEW DEGREES MORE THAN
TONIGHT...PRECLUDING ANY FROST FORMATION.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
LONG RANGE MODELS REMAIN IN UNUSUALLY GOOD AGREEMENT WITH THE
OVERALL H5 FLOW THROUGH THE LONG TERM PERIOD...LEADING TO ABOVE
AVERAGE CONFIDENCE IN THE FORECAST.
A CUTOFF LOW PRES SYSTEM OVER THE CA COAST TUE MORNING WILL TRY TO
TRACK INLAND...BUT WILL BE HALTED BY A STRENGTHENING SUBTROPICAL
RIDGE DOWNSTREAM OVER THE DEEP SOUTH. THIS RIDGE WILL AMPLIFY INTO
THE EASTERN US BEHIND A DEPARTING CUTOFF LOW AS ANOTHER TROUGH
TRAVERSES ALONG THE CENTRAL US/CANADA BORDER. AN OMEGA BLOCK OVER
THE CENTRAL ATLANTIC WILL KEEP THE DEPARTING UPPER LOW S OF NOVA
SCOTIA TUE NIGHT FROM PROGRESSING AND THE RIDGE OVER THE SOUTHERN US
WILL EVENTUALLY LOSE ITS GRIP ON THE NE AS THE TROUGH IN SRN CANADA
TRACKS EWD. THE LATTER TROUGH WILL ALSO CUTOFF AS IT MOVES INTO THE
GREAT LAKES REGION TRACKING THROUGH THE NE AT THE END OF THE WEEK.
THIS SYSTEM WILL EVENTUALLY CONSOLIDATE WITH THE CUTOFF NEAR NOVA
SCOTIA NEXT WEEKEND. AN UNSETTLED PATTERN WILL RESULT ACROSS THE
LOCAL AREA AS A RESULT.
AT THE SFC...HIGH PRES BUILDS OVER THE AREA ON TUE AND SLIDES
OFFSHORE TUE NIGHT AS A WARM FRONT APPROACHES FROM THE W. DRY AND
WARM WEATHER EXPECTED TUE WITH ABOVE NORMAL TEMPS IN THE MID TO
UPPER 70S. CLOUDS WILL BE ON THE INCREASE TUE NIGHT AS THE FRONT
APPROACHES. CHANCES FOR SHOWERS AND TSTMS WILL INCREASE ON WED AS
UPPER SUPPORT INCREASES...WITH EVEN BETTER CHANCED WED NIGHT AND THU
AS THE PARENT LOW PRES SYSTEM MOVES ACROSS THE AREA. HIGH TEMP
FORECAST FOR THU WILL LIKELY REMAIN TRICKY FOR THE NEXT SEVERAL DAYS
AS THE WARM FRONT MAY MAKE IT THROUGH SOME WESTERN ZONES. BUT WITH
THE LOW TRACK FROM NW TO SE...MOST OF THE AREA SHOULD REMAIN IN A
MARITIME AIRMASS. ELEVATED INSTABILITY REMAINS ON THE N SIDE OF THE
FRONT...WITH SFC BASED IN THE WARM SECTOR SO TSTMS FOR ALL WED AFTN
THROUGH THU.
AS THE UPPER ENERGY CONSOLIDATES FRI AND SAT...PIECES OF VORTICITY
WILL PINWHEEL THROUGH THE NORTHEAST FROM TIME TO TIME. DIFFICULT TO
PINPOINT THE TIMING THIS FAR OUT...BUT HAVE KEPT HIGHEST POPS
CONFINED TO DAYTIME WITH MORE OF A DIURNAL INFLUENCE. HIGH PRES
BUILDS IN FROM THE W SAT NIGHT AND SUN WITH DRY CONDS RETURNING.
TEMPERATURES FOR THE REMAINDER OF THE FORECAST PERIOD ARE EXPECTED
TO BE NEAR TO SLIGHTLY BELOW NORMAL LEVELS.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
MAINLY VFR THROUGH THE TAF PERIOD. WEAK SFC TROUGH WITH A GENERAL
NW FLOW AROUND 10 KT ALLOWING FOR SCT-BKN CLOUDS AROUND 5-8KFT.
GENERAL WIND GUSTS WILL BE 15-20KT BEFORE EARLY EVENING. CLOUDS
AND WINDS DIMINISH TONIGHT.
SOME BRIEF SHOWERS POSSIBLE INTO THE EARLY EVENING MAINLY FOR CITY
TERMINALS AND TO NORTHWEST WHICH COULD RESULT IN HIGHER BRIEF WIND
GUSTS...UP TO AROUND 25 KT. MONDAY COULD ALSO HAVE AN ISOLATED
SHOWER IN THE AFTERNOON.
ONLY EXCEPTION TO NW FLOW WOULD BE KGON WITH THE SEA BREEZE WITH IT
LOOKING LESS LIKELY AT KJFK...KISP...AND KBDR.
.OUTLOOK FOR 20Z MON THROUGH FRI...
.MON-MON EVE...MAINLY VFR. NW WINDS G20-25KT. ISOLD
SHRA/TSTM...RELATIVELY HIGHER CHANCE FOR EASTERN TERMINALS.
.LATE MON EVE-TUE EVENING...VFR.
.LATE TUE NIGHT-FRI...BRIEF MVFR OR LOWER CONDS ARE POSSIBLE WITH
ANY SCT SHOWERS/TSTMS...OTHERWISE VFR.
&&
.MARINE...
SUB-SCA CONDITIONS GENERALLY EXPECTED THROUGH THE COMING WEEK.
THE ONLY EXCEPTION WILL BE FRI NIGHT AS SLOWLY DEPARTING LOW PRES
MAY RESULT IN MARGINAL SCA SEAS ON THE OCEAN WATERS.
&&
.HYDROLOGY...
NO SIGNIFICANT RAINFALL IS EXPECTED THROUGH THE MIDDLE OF THE WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...24/SEARS
NEAR TERM...SEARS
SHORT TERM...SEARS
LONG TERM...24
AVIATION...JM
MARINE...24/SEARS
HYDROLOGY...24/SEARS
AREA FORECAST DISCUSSION
NWS ALBANY NY
125 PM EDT SUN MAY 18 2014
.SYNOPSIS...
COOL TEMPERATURES CONTINUE THIS AFTERNOON...AS A PASSING
UPPER LEVEL DISTURBANCE ALLOWS FOR SOME ISOLATED RAIN SHOWERS OR
SPRINKLES...MAINLY OVER THE HIGHER ELEVATIONS. THE THREAT FOR
ISOLATED TO SCATTERED RAIN SHOWERS WILL CONTINUE ON MONDAY AS THE
UPPER LEVEL DISTURBANCE STARTS TO MOVE AWAY FROM THE AREA. HIGH
PRESSURE WILL RETURN FOR TUESDAY WITH DRY WEATHER AND MILDER
TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 114 PM EDT...THE LATEST RUC40/RAP SHOWS A VORT MAX ROTATING
AROUND THE UPPER TROUGH CENTERED OVER THE SE ONTARIO/SW QUEBEC
CORRIDOR. SOME ISOLD-SCT SHOWERS HAVE POPPED UP OVER W-CNTRL
NY...AND SOME SPRINKLES/SHOWERS HAVE REACHED THE SRN DACKS. THE
MID LEVEL COLD POOL IS ABOUT -25C WITH THE UPPER LEVEL LOW. THE
SFC AND LOW LEVELS REMAIN DRY...BUT SOME INSTABILITY
SHOWERS/SPRINKLES WILL BE POSSIBLE THIS AFTERNOON...ESPECIALLY
OVER THE HIGHER TERRAIN. THE LATEST HRRR FAVORS LOCATIONS TO THE
NORTH AND WEST OF THE CAPITAL REGION...WITH THE NAM TO THE SOUTH.
THE VISIBLE SATELLITE PICTURE SHOWS AN EXPANSION OF THE CUMULUS
CLOUDS WEST OF THE HUDSON RIVER VALLEY...WHICH SHOULD
INCREASE...SOME PARTLY SUNNY CONDITIONS WILL PREVAIL PRIOR TO
SUNSET. THE CLOUDS SHOULD DISSIPATE QUICKLY THEREAFTER...WITH SOME
FROST POSSIBLE OVERNIGHT IN SOME LOCATIONS...ESPECIALLY NORTH AND
WEST OF THE CAPITAL DISTRICT...PERHAPS EAST INTO THE BERKSHIRES.
POSSIBLE FROST HEADLINES WILL BE ADDRESSED WITH THE NEXT UPDATE.
WITH THE COOL TEMPS ALOFT...MAX TEMPS WILL BE BELOW NORMAL THIS
AFTERNOON. VALLEY AREAS WILL BE IN THE MID 60S...WITH MID 50S TO
LOW 60S OVER THE HIGHER ELEVATIONS. A FEW SPOTS IN NW CT...THE MID
HUDSON VALLEY AND NEAR GLENS FALLS MAY REACH THE UPPER 60S. GOOD
MIXING WILL ALSO ALLOW FOR BREEZY NW WINDS 10-15 MPH...WITH A FEW
GUSTS 20-25 MPH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
FOR TONIGHT...INSTABILITY CLOUDS/SHOWERS WILL END WITH THE LOSS OF
DAYTIME HEATING. WINDS WILL ALSO DIMINISH...WHICH WILL ALLOW FOR
GOOD RADIATIONAL COOLING TO TAKE PLACE. AS A RESULT...ANOTHER
CHILLY NIGHT IS IN STORE FOR THE AREA...WITH MINS IN THE 30S TO
LOW 40S. SOME AREAS/PATCHES OF FROST WILL BE POSSIBLE...ESP IN THE
LAKE GEORGE SARATOGA AREA...SOUTHERN VT...AND NORTHERN BERKSHIRES.
THE EXTENT OF THE FROST IS STILL TOUGH TO DETERMINE...SO WE WILL
HOLD OFF ON ANY FROST ADVISORIES AT THIS POINT...BUT WILL
CERTAINLY MENTION IN THE HWO. OTHERWISE...DRY CONDITIONS ARE
EXPECTED WITH CLEAR TO PARTLY CLOUDY SKIES.
ON MONDAY...THE UPPER LEVEL TROUGH WILL START TO SHIFT SOUTHEAST
TOWARDS EASTERN NEW ENGLAND. THE TROUGH WILL REMAIN CLOSE TO
ENOUGH TO STILL HAVE AN IMPACT OVER THE AREA...WITH ISOLATED TO
SCATTERED DAYTIME RAIN SHOWERS ONCE AGAIN AND BREEZY CONDITIONS.
THE BEST THREAT WILL BE OVER THE HIGHER ELEVATIONS AGAIN. TEMPS
WILL CONTINUE TO BE COOL...ALTHOUGH THEY SHOULD BE A FEW DEGREES
WARMER THAN SUNDAY...WITH VALLEY HIGHS IN THE UPPER 60S...AND HIGH
TERRAIN IN THE UPPER 50S TO MID 60S.
WEAK HIGH PRESSURE WILL DRIFT OVER THE AREA FOR MONDAY NIGHT INTO
TUESDAY. THIS WILL END THE THREAT FOR ANY RAIN SHOWERS...AND KEEP
SKIES MAINLY CLEAR. IN ADDITION...TEMPS SHOULD BE A LITTLE WARMER
THAN RECENT DAYS. MINS ON MON NIGHT WILL GENERALLY BE IN THE 40S
/A FEW HIGH TERRAIN SPOTS STILL IN THE UPPER 30S/ AND DAYTIME
HIGHS WILL GENERALLY BE IN THE LOW TO MID 70S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE LONG TERM WILL BE CHARACTERIZED BY AN UNSETTLED WEATHER PATTERN
AS AN UPPER-LEVEL LOW EVENTUALLY STALLS ACROSS THE REGION.
H2O VAPOR LOOP THIS EARLY SUNDAY MORNING REVEALS A COMPLEX TROUGH
IMPACTING THE PACIFIC NORTHWEST WITH A POTENT JET MOVING ASHORE
ACROSS NORTHERN CALIFORNIA. THESE FEATURES WILL BE THE KEY PLAYERS
FOR THE UPCOMING FORECAST AS A WARM FRONT DEVELOPS ACROSS THE
NORTHERN TIER OF THE CONUS. THIS FEATURE PER THE GLOBAL MODEL
CONSENSUS MOVES ACROSS THE GREAT LAKES REGION AND INTO THE WESTERN
NY AND EASTERN PA TUESDAY NIGHT. AS TIMING OF THIS WARM FRONT HAS
SLOWED DOWN A BIT...WE WILL TRIM BACK POPS AND CONFINE THEM TO THE
WESTERN AREAS. AN INCREASE IN CLOUD COVER IS EXPECTED FROM WEST TO
EAST OVERNIGHT.
THE MAIN CHALLENGE ON WEDNESDAY IS DEPENDING ON HOW MUCH OF THE
FORECAST AREA GETS INTO THE WARM SECTOR. THERE MAY BE ENOUGH
ELEVATED INSTABILITY TO SUPPORT A FEW RUMBLES OF
THUNDER...ESPECIALLY SOUTH OF THE CAPITAL REGION. CLOUD COVER WILL
LIKELY THICKEN THROUGH THE DAY AND WILL INCREASE POPS ACROSS THE
ENTIRE REGION PER WPC GUIDANCE.
THE LOW PRESSURE SYSTEM WILL BE ASSOCIATED WITH A FAIRLY POTENT
UPPER-LEVEL SHORTWAVE TROUGH. THIS SYSTEM WILL BECOME
VERTICALLY-STACKED AS IT MOVES ACROSS THE REGION FOR THE LATER HALF
OF THE WEEK. LOOKING AT CURRENT HEMISPHERIC WATER VAPOR TRACES
SUGGEST A LOW WAVENUMBER ENERGETICS PATTERN...WHICH WILL CAUSE THE
SHORTWAVE TROUGH TO CLOSE OFF IN THE UPPER-LEVELS AND STALL ACROSS
THE NORTHEAST CORRIDOR.
THIS UPPER-LEVEL LOW WILL BRING CHANCES FOR SHOWERS THROUGH THE END
OF THE WORKWEEK AND CONTINUING THROUGH MUCH OF THE HOLIDAY WEEKEND.
CURRENT LONG RANGE GUIDANCE HAS THE UPPER-LEVEL LOW SLOWLY EXITING
TO THE EAST BY SUNDAY. FURTHER IMPROVEMENTS ARE NOW EXPECTED
HEADING INTO THE HOLIDAY WITH MILDER TEMPERATURES.
THE TEMPERATURES THROUGHOUT THE LONG TERM PERIOD WILL BE NEAR
SEASONABLE LEVELS...WITH HIGHS RANGING FROM NEAR 60 TO THE LOW 70S
AND LOWS RANGING FROM MID 40S TO MID 50S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE SLOWLY
NORTHEAST OUT OF THE REGION. IT HAS PRODUCED SOME CLOUDY CONDITIONS
WITH A FEW RAIN SHOWERS WELL WEST OF ALL TAF SITES. HOWEVER...AS WE
WORK INTO THE BEGINNING OF THE TAF PERIOD...ONLY SCATTERED MID
CLOUDS WILL BE MOVING INTO THE REGION ESPECIALLY AT KPOU. OTHERWISE
VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES THROUGHOUT THE TAF
PERIOD. CLOUDS WILL DIMINISH IN COVERAGE AS WE WORK THROUGH THE
OVERNIGHT PERIOD AND SOME AREAS ESPECIALLY IN THE MID HUDSON VALLEY
MAY EVEN CLEAR OUT COMPLETELY BY 12Z MONDAY. OUR NEXT POSSIBLE
WEATHER SYSTEM WILL WORK ITS WAY INTO THE REGION AFTER THE END OF
THE TAF PERIOD WITH POSSIBLE LIGHT RAIN SHOWERS.
WINDS WILL BE LIGHT OUT OF THE NORTHWEST TO NEAR CALM DURING THE
OVERNIGHT. WINDS WILL THEN PICK UP TO NEAR 10 KNOTS AS WE GO PAST
12Z MONDAY.
OUTLOOK...
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA.
&&
.FIRE WEATHER...
LOW RH VALUES AND GUSTY WINDS TODAY AND TOMORROW...
HEAVY RAINFALL OCCURRED ON FRIDAY INTO EARLY SATURDAY. RH VALUES
WILL DROP TO NEAR 30 PERCENT THIS AFTERNOON WITH NORTHWEST WINDS
OF 10 TO 15 MPH WITH A FEW HIGHER GUSTS. AN ISOLATED RAIN SHOWER
CANNOT BE RULED OUT...MAINLY FOR THE HIGH TERRAIN OF THE
CATSKILLS. RH VALUES WILL RETURN TO 75 TO 100 PERCENT TONIGHT
WITH WINDS DIMINISHING TO 5 MPH OR LESS. SOME DEW OR FROST
FORMATION IS POSSIBLE. RH VALUES WILL ONCE AGAIN DROP TO 30 TO 35
PERCENT ON MONDAY AFTERNOON WITH NORTHWEST WINDS OF 10 TO 20 MPH.
ISOLATED TO SCATTERED RAIN SHOWERS ARE POSSIBLE ON MONDAY.
&&
.HYDROLOGY...
RECENT HEAVY RAINFALL LED TO SIGNIFICANT RISES ON AREA RIVERS AND
STREAMS. A RIVER FLOOD WARNING CONTINUES FOR THE MOHAWK RIVER AT
UTICA. THE RIVER IS CURRENTLY FALLING...AND IS EXPECTED TO FALL
BEFORE FLOOD STAGE DURING THE AFTERNOON TODAY. ELSEWHERE...RIVER
LEVELS HAVE CRESTED AND ARE FALLING...ALTHOUGH A FEW OF THE LOWER
REACHES ALONG THE LARGER RIVERS /SUCH AS THE HOUSATONIC/ ARE JUST
CRESTING NOW. ALL RIVERS AND STREAMS ARE EXPECTED TO RECEDE...AS
LITTLE TO NO RAINFALL IS EXPECTED OVER THE NEXT FEW DAYS. ANY
RAINFALL THROUGH THIS TIME WILL BE FROM ISOLATED TO SCATTERED
LIGHT RAIN SHOWERS...WHICH WILL HAVE LITTLE TO NO HYDROLOGIC
IMPACT.
THE NEXT CHANCE FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS WILL
BE LATER THIS WEEK ON WEDNESDAY INTO THURSDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/WASULA
NEAR TERM...11/WASULA
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...LFM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
115 PM EDT SUN MAY 18 2014
.SYNOPSIS...
COOL TEMPERATURES CONTINUE THIS AFTERNOON...AS A PASSING
UPPER LEVEL DISTURBANCE ALLOWS FOR SOME ISOLATED RAIN SHOWERS OR
SPRINKLES...MAINLY OVER THE HIGHER ELEVATIONS. THE THREAT FOR
ISOLATED TO SCATTERED RAIN SHOWERS WILL CONTINUE ON MONDAY AS THE
UPPER LEVEL DISTURBANCE STARTS TO MOVE AWAY FROM THE AREA. HIGH
PRESSURE WILL RETURN FOR TUESDAY WITH DRY WEATHER AND MILDER
TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 114 PM EDT...THE LATEST RUC40/RAP SHOWS A VORT MAX ROTATING
AROUND THE UPPER TROUGH CENTERED OVER THE SE ONTARIO/SW QUEBEC
CORRIDOR. SOME ISOLD-SCT SHOWERS HAVE POPPED UP OVER W-CNTRL
NY...AND SOME SPRINKLES/SHOWERS HAVE REACHED THE SRN DACKS. THE
MID LEVEL COLD POOL IS ABOUT -25C WITH THE UPPER LEVEL LOW. THE
SFC AND LOW LEVELS REMAIN DRY...BUT SOME INSTABILITY
SHOWERS/SPRINKLES WILL BE POSSIBLE THIS AFTERNOON...ESPECIALLY
OVER THE HIGHER TERRAIN. THE LATEST HRRR FAVORS LOCATIONS TO THE
NORTH AND WEST OF THE CAPITAL REGION...WITH THE NAM TO THE SOUTH.
THE VISIBLE SATELLITE PICTURE SHOWS AN EXPANSION OF THE CUMULUS
CLOUDS WEST OF THE HUDSON RIVER VALLEY...WHICH SHOULD
INCREASE...SOME PARTLY SUNNY CONDITIONS WILL PREVAIL PRIOR TO
SUNSET. THE CLOUDS SHOULD DISSIPATE QUICKLY THEREAFTER...WITH SOME
FROST POSSIBLE OVERNIGHT IN SOME LOCATIONS...ESPECIALLY NORTH AND
WEST OF THE CAPITAL DISTRICT...PERHAPS EAST INTO THE BERKSHIRES.
POSSIBLE FROST HEADLINES WILL BE ADDRESSED WITH THE NEXT UPDATE.
WITH THE COOL TEMPS ALOFT...MAX TEMPS WILL BE BELOW NORMAL THIS
AFTERNOON. VALLEY AREAS WILL BE IN THE MID 60S...WITH MID 50S TO
LOW 60S OVER THE HIGHER ELEVATIONS. A FEW SPOTS IN NW CT...THE MID
HUDSON VALLEY AND NEAR GLENS FALLS MAY REACH THE UPPER 60S. GOOD
MIXING WILL ALSO ALLOW FOR BREEZY NW WINDS 10-15 MPH...WITH A FEW
GUSTS 20-25 MPH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
FOR TONIGHT...INSTABILITY CLOUDS/SHOWERS WILL END WITH THE LOSS OF
DAYTIME HEATING. WINDS WILL ALSO DIMINISH...WHICH WILL ALLOW FOR
GOOD RADIATIONAL COOLING TO TAKE PLACE. AS A RESULT...ANOTHER
CHILLY NIGHT IS IN STORE FOR THE AREA...WITH MINS IN THE 30S TO
LOW 40S. SOME AREAS/PATCHES OF FROST WILL BE POSSIBLE...ESP IN THE
LAKE GEORGE SARATOGA AREA...SOUTHERN VT...AND NORTHERN BERKSHIRES.
THE EXTENT OF THE FROST IS STILL TOUGH TO DETERMINE...SO WE WILL
HOLD OFF ON ANY FROST ADVISORIES AT THIS POINT...BUT WILL
CERTAINLY MENTION IN THE HWO. OTHERWISE...DRY CONDITIONS ARE
EXPECTED WITH CLEAR TO PARTLY CLOUDY SKIES.
ON MONDAY...THE UPPER LEVEL TROUGH WILL START TO SHIFT SOUTHEAST
TOWARDS EASTERN NEW ENGLAND. THE TROUGH WILL REMAIN CLOSE TO
ENOUGH TO STILL HAVE AN IMPACT OVER THE AREA...WITH ISOLATED TO
SCATTERED DAYTIME RAIN SHOWERS ONCE AGAIN AND BREEZY CONDITIONS.
THE BEST THREAT WILL BE OVER THE HIGHER ELEVATIONS AGAIN. TEMPS
WILL CONTINUE TO BE COOL...ALTHOUGH THEY SHOULD BE A FEW DEGREES
WARMER THAN SUNDAY...WITH VALLEY HIGHS IN THE UPPER 60S...AND HIGH
TERRAIN IN THE UPPER 50S TO MID 60S.
WEAK HIGH PRESSURE WILL DRIFT OVER THE AREA FOR MONDAY NIGHT INTO
TUESDAY. THIS WILL END THE THREAT FOR ANY RAIN SHOWERS...AND KEEP
SKIES MAINLY CLEAR. IN ADDITION...TEMPS SHOULD BE A LITTLE WARMER
THAN RECENT DAYS. MINS ON MON NIGHT WILL GENERALLY BE IN THE 40S
/A FEW HIGH TERRAIN SPOTS STILL IN THE UPPER 30S/ AND DAYTIME
HIGHS WILL GENERALLY BE IN THE LOW TO MID 70S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM WILL BE CHARACTERIZED BY AN UNSETTLED WEATHER PATTERN
AS AN UPPER-LEVEL LOW EVENTUALLY STALLS ACROSS THE REGION.
H2O VAPOR LOOP THIS EARLY SUNDAY MORNING REVEALS A COMPLEX TROUGH
IMPACTING THE PACIFIC NORTHWEST WITH A POTENT JET MOVING ASHORE
ACROSS NORTHERN CALIFORNIA. THESE FEATURES WILL BE THE KEY PLAYERS
FOR THE UPCOMING FORECAST AS A WARM FRONT DEVELOPS ACROSS THE
NORTHERN TIER OF THE CONUS. THIS FEATURE PER THE GLOBAL MODEL
CONSENSUS MOVES ACROSS THE GREAT LAKES REGION AND INTO THE WESTERN
NY AND EASTERN PA TUESDAY NIGHT. AS TIMING OF THIS WARM FRONT HAS
SLOWED DOWN A BIT...WE WILL TRIM BACK POPS AND CONFINE THEM TO THE
WESTERN AREAS. AN INCREASE IN CLOUD COVER IS EXPECTED FROM WEST TO
EAST OVERNIGHT.
THE MAIN CHALLENGE ON WEDNESDAY IS DEPENDING ON HOW MUCH OF THE
FORECAST AREA GETS INTO THE WARM SECTOR. THERE MAY BE ENOUGH
ELEVATED INSTABILITY TO SUPPORT A FEW RUMBLES OF
THUNDER...ESPECIALLY SOUTH OF THE CAPITAL REGION. CLOUD COVER WILL
LIKELY THICKEN THROUGH THE DAY AND WILL INCREASE POPS ACROSS THE
ENTIRE REGION PER WPC GUIDANCE.
THE LOW PRESSURE SYSTEM WILL BE ASSOCIATED WITH A FAIRLY POTENT
UPPER-LEVEL SHORTWAVE TROUGH. THIS SYSTEM WILL BECOME
VERTICALLY-STACKED AS IT MOVES ACROSS THE REGION FOR THE LATER HALF
OF THE WEEK. LOOKING AT CURRENT HEMISPHERIC WATER VAPOR TRACES
SUGGEST A LOW WAVENUMBER ENERGETICS PATTERN...WHICH WILL CAUSE THE
SHORTWAVE TROUGH TO CLOSE OFF IN THE UPPER-LEVELS AND STALL ACROSS
THE NORTHEAST CORRIDOR.
THIS UPPER-LEVEL LOW WILL BRING CHANCES FOR SHOWERS THROUGH THE END
OF THE WORKWEEK AND CONTINUING THROUGH MUCH OF THE HOLIDAY WEEKEND.
CURRENT LONG RANGE GUIDANCE HAS THE UPPER-LEVEL LOW SLOWLY EXITING
TO THE EAST BY SUNDAY. FURTHER IMPROVEMENTS ARE NOW EXPECTED
HEADING INTO THE HOLIDAY WITH MILDER TEMPERATURES.
THE TEMPERATURES THROUGHOUT THE LONG TERM PERIOD WILL BE NEAR
SEASONABLE LEVELS...WITH HIGHS RANGING FROM NEAR 60 TO THE LOW 70S
AND LOWS RANGING FROM MID 40S TO MID 50S.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
AN UPPER LEVEL LOW WILL CONTINUE TO INFLUENCE OUR WEATHER THE
NEXT FEW DAYS...AS HIGH PRESSURE WILL TRY TO BUILD IN FROM THE
MIDWEST AND OHIO VALLEY.
VFR CONDITIONS ARE EXPECTED THE NEXT 24 HRS. A FEW-SCT CUMULUS AND
SOME SCT-BKN MID LEVEL CLOUDS WILL BE AROUND TODAY WITH THE UPPER
TROUGH MOVING OVER THE REGION...AND ITS ASSOCIATED COLD POOL. THERE
MAY BE SOME ISOLD INSTABILITY SHOWERS AROUND ESPECIALLY NEAR THE
HIGHER TERRAIN /KPSF/...BUT THIS CONTINUE TO BE LEFT OUT OF THE
TERMINALS FOR NOW...SINCE THE PROBABILITY OF A SHOWER IS LOW. THE
EXCEPTION TO THIS WILL BE FOR KPOU. EXPERIENTIAL HRRR/HIRESWRF
FORECAST REFLECTIVITY FORECASTS FOR THE PAST SEVERAL RUNS HAVE
INDICATED SHOWER CHANCES FOR THE CATSKILLS AND MID HUDSON VALLEY ARE
SLIGHTLY ELEVATED AS WE WILL INCLUDE A VCSH AT THIS TIME.
WINDS WILL INCREASE FROM THE N TO NW AT 7-12 KTS BY THE LATE MORNING
AND EARLY AFTERNOON WITH SOME GUSTS IN 16-18 KT RANGE AT KALB/KPSF.
OUTLOOK...
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
LOW RH VALUES AND GUSTY WINDS TODAY AND TOMORROW...
HEAVY RAINFALL OCCURRED ON FRIDAY INTO EARLY SATURDAY. RH VALUES
WILL DROP TO NEAR 30 PERCENT THIS AFTERNOON WITH NORTHWEST WINDS
OF 10 TO 15 MPH WITH A FEW HIGHER GUSTS. AN ISOLATED RAIN SHOWER
CANNOT BE RULED OUT...MAINLY FOR THE HIGH TERRAIN OF THE
CATSKILLS. RH VALUES WILL RETURN TO 75 TO 100 PERCENT TONIGHT
WITH WINDS DIMINISHING TO 5 MPH OR LESS. SOME DEW OR FROST
FORMATION IS POSSIBLE. RH VALUES WILL ONCE AGAIN DROP TO 30 TO 35
PERCENT ON MONDAY AFTERNOON WITH NORTHWEST WINDS OF 10 TO 20 MPH.
ISOLATED TO SCATTERED RAIN SHOWERS ARE POSSIBLE ON MONDAY.
&&
.HYDROLOGY...
RECENT HEAVY RAINFALL LED TO SIGNIFICANT RISES ON AREA RIVERS AND
STREAMS. A RIVER FLOOD WARNING CONTINUES FOR THE MOHAWK RIVER AT
UTICA. THE RIVER IS CURRENTLY FALLING...AND IS EXPECTED TO FALL
BEFORE FLOOD STAGE DURING THE AFTERNOON TODAY. ELSEWHERE...RIVER
LEVELS HAVE CRESTED AND ARE FALLING...ALTHOUGH A FEW OF THE LOWER
REACHES ALONG THE LARGER RIVERS /SUCH AS THE HOUSATONIC/ ARE JUST
CRESTING NOW. ALL RIVERS AND STREAMS ARE EXPECTED TO RECEDE...AS
LITTLE TO NO RAINFALL IS EXPECTED OVER THE NEXT FEW DAYS. ANY
RAINFALL THROUGH THIS TIME WILL BE FROM ISOLATED TO SCATTERED
LIGHT RAIN SHOWERS...WHICH WILL HAVE LITTLE TO NO HYDROLOGIC
IMPACT.
THE NEXT CHANCE FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS WILL
BE LATER THIS WEEK ON WEDNESDAY INTO THURSDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/WASULA
NEAR TERM...11/WASULA
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
516 PM EDT SUN MAY 18 2014
.SYNOPSIS...
A FRONT AND UPPER LEVEL DISTURBANCE WILL BRING SHOWERS...AND
POSSIBLE THUNDERSTORMS INTO THE EVENING HOURS. HIGH PRESSURE WILL
DOMINATE MONDAY THROUGH THE MIDDLE OF THE WEEK. A WARMING TREND
WILL OCCUR AS AN UPPER RIDGE BUILDS ACROSS THE SOUTH.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A MID-LEVEL SHORTWAVE TROUGH WAS HELPING SUPPORT SHOWERS. THE
MODELS SHOW LIFT ASSOCIATED WITH THIS FEATURE SHIFTING EAST
OVERNIGHT. THE LATEST HRRR DISPLAYS SPOTTY LINGERING RAIN EXITING
THE EAST PART AROUND 200 AM. H85 WESTERLY FLOW HAS LIMITED
MOISTURE. BELIEVE RAIN WILL REMAIN MAINLY LIGHT. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
ONE MORE MILD DAY ON TAP BEFORE THE WARM UP REALLY BEGINS. THE MAIN
UPPER WILL BEGIN TO BUILD ACROSS THE SOUTHERN MISSISSIPPI VALLEY
REGION...WHILE THE MAIN EAST COAST TROUGH PUSHES FURTHER OFF THE
COAST. EXPECT TO HAVE A DRY NORTHWESTERLY WIND FLOW ALOFT ACROSS
THE REGION. AT THE SURFACE...EXPECT HIGH PRESSURE TO BEGIN
BUILDING BACK INTO THE REGION...BRINGING FAIR WEATHER WITH IT.
DAYTIME HIGHS ON MONDAY WILL CLIMB INTO THE MID TO UPPER 70S.
MONDAY NIGHT WILL STILL BE COOL...WITH READINGS AROUND 50
POSSIBLE.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THE MAIN UPPER RIDGE WILL BUILD EASTWARD OVER THE DEEP SOUTH...BUT
WILL REMAIN CENTERED TO OUR WEST. A PAIR OF UPPER LOWS WILL
CONTINUE TO DEVELOP/SPIN TO OUR NORTHEAST. THIS KEEPS THE REGION
UNDER NORTHWESTERLY FLOW ALOFT...WITH A WESTERLY FLOW AT THE
SURFACE. THIS SHOULD PROVIDE A DRY PATTERN THROUGH MUCH OF THE
WORKWEEK. IT WILL ALSO BRING MUCH WARMER TEMPERATURES BACK TO THE
REGION...WITH 80S EXPECTED TUESDAY...AND THEN 90S THROUGH THE END
OF THE WEEK.
A WEAK FRONT OR UPPER IMPULSE OR TWO MAY AFFECT OUR REGION BY
NEST WEEKEND...AND MAY PROVIDE A CHANCE OF CONVECTION. WILL
CONTINUE WITH SLIGHT CHANCE POPS DUE TO OVERALL ATMOSPHERIC
MOISTURE APPEARING LOW.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
CURRENT CONDITIONS ACROSS THE REGION VARY FROM VFR...TO AREAS OF
IFR. EXPECT THESE TYPES OF CONDITIONS TO CONTINUE THROUGH 02Z AT
ALL TAF SITES...WITH VFR DROPPING DOWN TO IFR FOR BRIEF
PERIODS...THEN BACK UP TO VFR. THEN ADD IN PERIODS OF LIGHT
RAINFALL THROUGH 02Z ALSO. DUE TO THE VARIABILITY IN
CEILINGS...THIS IS A LOW CONFIDENCE FORECAST IN REGARDS TO THE
CEILING CONDITIONS THROUGH MUCH OF THE PERIOD. WINDS SHOULD BE
LIGHT AND VARIABLE
DRYING IS FORECAST TO BEGIN LATER ON TONIGHT AS THE MAIN UPPER
SYSTEM MOVES EAST OF THE AREA. CURRENTLY FORECASTING VFR OVERNIGHT
AND INTO MONDAY. WITH SOME LINGERING LOW-LEVEL MOISTURE...CAN NOT
COMPLETELY RULE OUT SOME MVFR/IFR VISIBILITY RESTRICTIONS TOWARDS
MORNING. HOWEVER MODELS NOT REALLY TRENDING THAT WAY...SO
CONFIDENCE LOW IN DEVELOPMENT AT THIS TIME...SO HAVE LEFT OUT OF
CURRENT FORECAST AND WILL LET LATER SHIFTS RE-EVALUATE. MONDAY WILL
BE DRY WITH VFR THROUGH THE DAY.
.EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED AT THIS TIME.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
323 AM EDT SUN MAY 18 2014
.SHORT TERM /TODAY THROUGH MONDAY/...
AN UPPER DISTURBANCE WILL MOVE THROUGH THE CWFA TODAY. LONGWAVE
TROUGH CURRENTLY SITUATED ACROSS THE EASTERN PART OF THE COUNTRY.
SHORTWAVE ENERGY WILL ROUND THE BASE OF THE TROUGH TODAY...EACH
HELPING TO INCREASE THE POTENTIAL FOR SHRA/TSRA ACTIVITY ACROSS THE
AREA. THE TROUGH WILL BEGIN TO SHIFT OFFSHORE LATE TONIGHT INTO
EARLY MONDAY WITH RIDGING WILL BUILDING ALOFT.
500MB ANALYSIS SHOWS A SHORTWAVE MOVING ACROSS NORTHERN GA THIS
MORNING. THIS FEATURE HAS HELPED SUSTAIN SOME SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS THE NORTHERN ZONES THIS MORNING. THIS AXIS OF
PRECIP WILL CONTINUE TO SHIFT SOUTH EARLY THIS MORNING. THUNDERSTORM
ACTIVITY SHOULD REMAIN MOSTLY ISOLATED IN NATURE...BUT THE STORMS
WILL HAVE THE POTENTIAL TO PRODUCE SOME SMALL HAIL AND GUSTY WINDS.
COPIOUS CLOUD COVER FROM THIS MORNINGS ACTIVITY SHOULD HELP INHIBIT
INSTABILITY MAINLY ACROSS AREAS NORTH OF INTERSTATE 20 THIS
AFTERNOON. HOWEVER...A FEW RUMBLES OF THUNDER ARE POSSIBLE THROUGH
THE MID AFTERNOON HOURS...ESPECIALLY NEAR THE DIFFERENTIAL HEATING
BOUNDARY.
AREAS SOUTH OF INTERSTATE 20 SHOULD RECEIVE SOME GOOD
SUNSHINE THIS AFTERNOON...THUS MORE HEATING. WITH A SECOND PIECE OF
SHORTWAVE ENERGY ROUNDING THE BASE OF THE TROUGH DURING THE
AFTERNOON HOURS...THIS WILL SERVE TO STEEPEN THE LAPSE RATES ACROSS
PORTIONS OF CENTRAL AND SOUTH CENTRAL GA. FORECAST SOUNDINGS SHOW A
GOOD INVERTED V STRUCTURE FOR THE AFTERNOON...SO EXPECT
THUNDERSTORMS TO CONTAIN GUSTY WINDS. WITH THE STEEP LAPSE
RATES...THERE IS ALSO SOME POTENTIAL FOR HAIL. THERE IS ALSO
POTENTIAL FOR ISOL/SCT SEVERE THUNDERSTORMS TO DEVELOP DURING THE
AFTERNOON HOURS. AREAS ALONG AND SOUTH OF THE I-20 CORRIDOR WILL
HAVE THE BEST CHANCES FOR SEVERE CONVECTION. GUSTY WINDS AND LARGE
HAIL WILL BE THE PRIMARY THREATS WITH ANY SEVERE THUNDERSTORMS THAT
DEVELOP.
INSTABILITY SHOULD BEGIN TO WANE WITH THE LOSS OF HEATING EARLY THIS
EVENING AND CONVECTIVE ACTIVITY SHOULD DIMINISH. WITH RIDGING ALOFT
AND AT THE SURFACE ON MONDAY...CHANCES FOR PRECIP ARE TOO LOW TO
MENTION AT THIS TIME.
NLISTEMAA
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
RIDGING OVER THE SOUTH CENTRAL CONUS BUILDS INTO THE SOUTHEAST FOR
THE EXTENDED. THIS WILL RESULT IN A WARMING TREND IN TERMS OF THE
TEMPERATURES WITH MAXIMUM TEMPERATURES REACHING THE UPPER 80S AND
LOWER 90S BY THE END OF THE WEEK. ALTHOUGH IT DOESNT LOOK LIKE THESE
VALUES WOULD BREAK ANY RECORDS FOR MID TO LATE MAY...IT WILL BRING
HIGH TEMPERATURES AROUND 5 TO 10 DEGREES ABOVE NORMAL. THE RIDGING
ACROSS THE CWA WILL KEEP THE AREA DRY THROUGH MUCH OF THE EXTENDED.
BY FRIDAY THOUGH...THE RIDGING BEGINS TO WEAKEN ACROSS THE AREA AND
WITH A BOUNDARY SLIDING SOUTHWARD...COULD SEE A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS NORTH GEORGIA ON BOTH FRIDAY AND
SATURDAY.
11
&&
.AVIATION...
06Z UPDATE...
STRONG UPPER DISTURBANCE TO MOVE THROUGH THE REGION TODAY. THIS
FEATURE WILL BE ACCOMPANIED BY SHOWERS AND SCT THUNDERSTORMS. HAVE
GONE PRETTY CLOSE TO THE HRRR WITH THE TIMING OF THE SHRA. THE ONE
THING THAT MAY HAVE TO BE CHANGED IN LATER UPDATES IS THE
TIMING/COVERAGE OF THE TSRA. HRRR ISNT INDICATING MUCH OF A CHANCE
ACROSS THE NORTHERN TERMINALS...BUT DO THINK THERE WILL BE A FEW
THUNDERSTORMS AROUND. INSTABILITY MAY BE LIMITED BY THE COPIOUS
CLOUD COVER EARLY ON. MCN/CSG MAY HAVE THE BEST CHANCES FOR
STRONGER/BETTER COVERAGE OF THUNDERSTORMS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON TIMING/COVERAGE OF THUNDERSTORMS ACROSS ATL.
OTHERWISE...HIGH CONFIDENCE REMAINING ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 50 75 55 / 60 10 10 0
ATLANTA 70 52 76 60 / 60 10 10 0
BLAIRSVILLE 58 44 72 52 / 60 10 10 0
CARTERSVILLE 64 50 77 56 / 60 10 10 0
COLUMBUS 79 57 81 62 / 40 20 10 5
GAINESVILLE 60 49 74 57 / 60 10 10 0
MACON 80 55 78 58 / 50 20 10 5
ROME 65 50 78 56 / 60 10 10 0
PEACHTREE CITY 72 52 77 55 / 60 10 10 0
VIDALIA 83 59 78 61 / 40 40 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NLISTEMAA
LONG TERM....11
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
143 AM EDT SUN MAY 18 2014
.PREV DISCUSSION... /ISSUED 817 PM EDT SAT MAY 17 2014/
PREV DISCUSSION... /ISSUED 348 PM EDT SAT MAY 17 2014/
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
IN THE SHORT TERM...THE FORECAST AREA WILL CONTINUE TO BE AFFECTED
BY SHORT WAVES MOVING ALONG A SURFACE BOUNDARY. THE FIRST WAVE
CROSSED NORTH GA THIS MORNING AND WAS CURRENTLY IN THE CAROLINAS.
HOWEVER SHOWERS SHOULD PERSIST ALONG THE SURFACE FRONT IN THE
VICINITY OF THE GA/TN BORDER. THE NEXT WAVE WILL PUSH INTO GA
OVERNIGHT AND SUNDAY. THIS WAVE SHOULD BE STRONGER WITH THE
POTENTIAL FOR A FEW THUNDERSTORMS. NOT EXPECTING SEVERE AT THIS TIME
BUT VERTICAL SHEAR AND MODERATE LAPSE RATES SHOULD ALLOW FOR THE
POSSIBILITY OF LARGE HAIL AND STRONG WINDS SUNDAY AFTERNOON. THIS
IMPULSE SHOULD SINK INTO CENTRAL GA AND WEAKEN SUNDAY EVENING. HAVE
KEPT THE BEST POPS ACROSS THE NORTH THROUGH THE PERIOD...GRADUALLY
DIMINISHING POPS FROM NORTH TO SOUTH SUNDAY AFTERNOON AND EVENING.
HAVE STAYED CLOSE TO A GUIDANCE BLEND OF MAX/MIN NUMBERS. CLOUDY
SKIES SHOULD HELP KEEP TEMPERATURES COOL ON SUNDAY.
41
LONG TERM /MONDAY THROUGH SATURDAY/...
NO MAJOR CHANGES MADE TO THE EXTENDED FORECAST. A QUICK GLANCE AT
THE 00Z GEFS SPAGHETTI PLOTS DISPLAY THAT MOST OF THE SOLUTIONS
AGREE WITH THE OPERATIONAL GFS THROUGH THE END OF THE WEEK. AT
THIS TIME SPREAD THE SLIGHT CHANCE OF RAIN DOWN THE EASTERN ZONES
TO ACCOUNT FOR HPC GUIDANCE AND QPF FORECASTS FROM THE LONG RANGE
MODELS. PREVIOUS LONG TERM DISCUSSION IS ATTACHED BELOW.
ARG
PREV DISCUSSION... /ISSUED 327 AM EDT SAT MAY 17 2014/
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
TAIL END THE UPPER LEVEL TROUGH WILL BE EXITING THE AREA AT THE
BEGINNING OF THE EXTENDED SO INITIALLY HAVE KEPT A SLIGHT CHANCE
OF SHOWERS ACROSS THE SOUTHERN PORTION OF THE CWA FOR SUNDAY
NIGHT. AFTER THIS...UPPER RIDGE BUILDS INTO THE CWA BY TUESDAY.
THIS WILL RESULT IN A WARMING TREND WITH HIGH TEMPERATURES WARMING
INTO THE 80S AND EVEN SOME LOWER 90S FOR THE SECOND HALF OF THE
WORK WEEK. FOR THE MOST PART...RIDGING DOMINATES THROUGH THE
EXTENDED AND KEEPS THE CWA DRY. SOME PERTURBATIONS IN THE NORTHWEST
FLOW ACROSS THE OHIO VALLEY...WITH THE ECMWF EVEN A LITTLE FURTHER
SOUTH INTO THE TN VALLEY...BUT APPEARS AT THIS POINT THESE
DISTURBANCES SHOULD REMAIN NORTH OF THE CWA. ONE WAVE IS A LITTLE
CLOSER TO NORTH GEORGIA ON FRIDAY...SO JUST A MENTION OF SLIGHT
CHANCE POPS ACROSS THE FAR NORTH FOR THAT TIME PERIOD.
11
&&
.AVIATION...
06Z UPDATE...
STRONG UPPER DISTURBANCE TO MOVE THROUGH THE REGION TODAY. THIS
FEATURE WILL BE ACCOMPANIED BY SHOWERS AND SCT THUNDERSTORMS. HAVE
GONE PRETTY CLOSE TO THE HRRR WITH THE TIMING OF THE SHRA. THE ONE
THING THAT MAY HAVE TO BE CHANGED IN LATER UPDATES IS THE TIMING/COVERAGE
OF THE TSRA. HRRR ISNT INDICATING MUCH OF A CHANCE ACROSS THE
NORTHERN TERMINALS...BUT DO THINK THERE WILL BE A FEW
THUNDERSTORMS AROUND. INSTABILITY MAY BE LIMITED BY THE COPIOUS CLOUD
COVER EARLY ON. MCN/CSG MAY HAVE THE BEST CHANCES FOR
STRONGER/BETTER COVERAGE OF THUNDERSTORMS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON TIMING/COVERAGE OF THUNDERSTORMS ACROSS ATL.
OTHERWISE...HIGH CONFIDENCE REMAINING ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 51 77 53 / 60 10 10 5
ATLANTA 70 54 76 57 / 60 10 10 5
BLAIRSVILLE 64 46 72 48 / 60 10 10 5
CARTERSVILLE 65 50 77 53 / 60 10 10 5
COLUMBUS 80 58 81 59 / 40 20 10 5
GAINESVILLE 65 52 74 54 / 60 10 10 5
MACON 79 54 80 55 / 50 20 10 5
ROME 67 50 79 53 / 60 10 10 5
PEACHTREE CITY 72 52 78 54 / 60 10 10 5
VIDALIA 83 59 80 58 / 40 40 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1253 AM EDT SUN MAY 18 2014
.SYNOPSIS...
ISSUED AT 1250 AM EDT SUN MAY 16 2014
AN UPPER LEVEL TROUGH WILL CONTINUE TO EXIT THE REGION OVERNIGHT
ALLOWING A RIDGE OF HIGH PRESSURE TO TRACK INTO THE REGION. THIS
WILL RESULT IN LIGHT WINDS OVERNIGHT WITH A POTENTIAL OF SOME
PATCHY FROST EARLY SUNDAY MORNING. THIS RIDGE WILL SHIFT EAST OF
THE AREA SUNDAY ALLOWING FOR A RETURN OF SOUTH WINDS...AND THE
BEGINNING OF A NOTICEABLE WARMING TREND THAT WILL CONTINUE INTO
MID WEEK.
&&
.UPDATE...
ISSUED AT 747 PM EDT SAT MAY 17 2014
A FEW ISOLATED SHOWERS PERSIST EARLY THIS EVENING PRIMARILY EAST
OF INTERSTATE 69. A FAIRLY COMPACT VORT MAX PER WATER VAPOR
IMAGERY/22Z RAP ANALYSIS WILL CONTINUE TO DEPART THE AREA OVER
NEXT HOUR WITH STRONGEST DPVA ALREADY HAVING SHIFTED EAST OF THE
LOCAL AREA AS OF 00Z. OTHERWISE...MAIN CONCERN FOR REMAINDER OF
THE NIGHT WILL BE ON TEMPERATURE TRENDS AND FROST CONCERNS.
DIURNALLY ENHANCED CU WILL DIMINISH EARLY THIS EVENING AND GIVEN
WEAK NATURE TO ADDITIONAL UPSTREAM SHORT WAVES...HAVE MADE SOME
MINOR TWEAKS TO LESS CLOUDINESS FOR LATE EVENING. EARLIER CLEARING
TREND AND POSITION OF SFC RIDGE DOES LEND SOME CONCERN AS TO FROST
POTENTIAL...ESPECIALLY ACROSS NORTHWEST OHIO DUE TO EXPECTED
POSITION OF DEPARTING LOW LEVEL THERMAL TROUGH. WILL HOLD OFF ON
ANY HEADLINE ISSUANCE AT THIS TIME WITH LOWS GENERALLY IN THE MID
TO UPPER 30S. HAVE UPDATED ZONES TO REMOVE AFTERNOON WORDING AND
WILL NEED TO WATCH OBSERVATIONAL TRENDS OVER NEXT FEW HOURS IN
TERMS OF TEMPS. WILL ALSO BE ISSUING A LATE EVENING UPDATE TO
REMOVE ISOLD SHOWER WORDING FROM THE EAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 407 PM EDT SAT MAY 17 2014
A SHORT WAVE TROF WAS MOVING SOUTHEAST ACROSS THE WESTERN GREAT
LAKES REGION THIS AFTERNOON. SHOWERS WERE ASSOCIATED WITH THIS UPPER
TROF AND HAVE BEEN EXPANDING IN COVERAGE OVER NRN INDIANA AND SW
LOWER MICHIGAN AS LIMITED DAY TIME HEATING WAS HELPING TO SUPPORT
SHOWER DEVELOPMENT. HAVE UPDATED GRIDS/FCST EARLIER TO INCREASE
COVERAGE OF SHOWERS AND ADD SMALL HAIL THIS AFTERNOON. THE LATEST
MODIFIED SOUNDINGS INDICATED SOME WARMING AT LEVELS ABOVE 700 MB
THIS AFTERNOON...HOWEVER...EXTREMELY COLD MID LEVEL TEMPS IN
ADDITION TO WEAK SHORT WAVE ENERGY WILL COMBINE TO PRODUCE SHOWERS
WITH ISOLATED THUNDER THIS AFTERNOON. LAPSE RATES WILL STEEPEN
ENOUGH WITH LOW CAPES...BUT ALSO WITH VERY LOW WET BULB ZERO HEIGHTS
TO SUPPORT ISOLATED SMALL HAIL. HAVE DECIDED TO REMOVE THUNDER AND
HAIL JUST BEFORE FORECAST ISSUANCE. THE MID LEVEL WARMING AND THE
LATEST CC/ZDR ON THE DUAL POL RADAR SUPPORTED JUST RAIN AT THE
SURFACE. ALSO...HAVE NOT RECEIVED ANY MORE HAIL REPORTS SINCE THIS
MORNING. THE UPSTREAM CLOUDS OVER WISCONSIN WERE MOSTLY DIURNALLY
DRIVEN...SO EXPECTED OVERALL COVERAGE TO DIMINISH THIS EVENING. A
SECOND UPPER TROF WAS ENTERING NRN MINNESOTA THIS AFTERNOON. THIS
SYSTEM SHOULD RACE SOUTHEAST TONIGHT...BUT IS EXPECTED TO HAVE
LIMITED CLOUDS WITH NO PRECIPITATION. AS FOR TEMPERATURES...THE
GFS/MAV AND NAM/MET HAVE BEEN DOING REASONABLY WELL THE PAST COUPLE
OF DAYS...SO HAVE ATTEMPTED TO FOLLOW. EXPANDED PATCHY FROST TONIGHT
WITH THE ANTICIPATION OF CLEARING SKIES.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 407 PM EDT SAT MAY 17 2014
UPR RIDGE OVER THE ROCKIES TODAY WILL MOVE EAST THROUGH THE PLAINS
SUNDAY NIGHT. MOSTLY CLEAR SKIES AND LIGHT WINDS AS SFC HIGH LINGERS
OVER OH SUNDAY NIGHT SHOULD PROVIDE DECENT RADIATIONAL COOLING...
ESPECIALLY ERN ZONES WITH TEMPS FALLING ABOUT 20F FROM AFTN HIGHS
TO LOWS IN THE L-M40S.
UPR LEVEL RIDGE WILL MOVE OVER OUR CWA ON MONDAY PROVIDING A
CONTINUATION TO THE WARMING TREND. INCREASING HIGH CLOUDINESS
EXPECTED IN THE AFTN BUT STRENGTHENING LOW LEVEL GRADIENT MIXING/WAA
SHOULD COMPENSATE ALLOWING FOR RATHER LARGE DIURNAL RISE WITH HIGHS
IN THE L70S OVER MOST OF THE CWA.
LEAD SHRTWV AHEAD OF DIGGING WEST COAST TROF WILL MOVE EAST ACROSS
THE NRN PLAINS MONDAY NIGHT-TUE CAUSING A WARM FRONT TO LIFT NE
ACROSS OUR CWA. RATHER STRONG LOW LEVEL THETA-E ADVECTION WILL
ACCOMPANY THE WARM FROPA WITH WK ELEVATED INSTABILITY... BUT CAPPING
AROUND 12KFT SHOULD LIMIT CONVECTIVE DEPTH SO CONTD WITH JUST A
SLIGHT CHC TO CHC OF SHOWERS WITH HIGHEST POPS N-NE PORTION OF CWA
WHERE BETTER MID LEVEL MOISTURE AND WEAKER CAPPING EXPECTED.
SHRTWV MOVG THROUGH TOP OF THE RIDGE OVER THE UPR GRTLKS WILL WEAKEN
MID LEVEL CAPPING TUE NGT AS ASSOCIATED SFC CDFNT MOVES INTO OUR
AREA. THIS MAY ALLOW SOME TSTMS TO DEVELOP TUE NGT INTO WED AS FRONT
MAKES SLOW PROGRESS ACROSS THE AREA. TEMPS SHOULD BE ABOVE NORMAL
AHEAD OF THE FRONT WITH HIGHS IN THE U70S/L80S AND LOWS IN THE
L-M60S TUE-WED.
MID-WEEK RIDGE TOPPING SHRTWV EXPECTED TO CUT-OFF OVER THE NERN U.S.
AND DRIFT SLOWLY E-NE LATE WEEK WITH RIDGING CONTG IN ITS WAKE
ACROSS THE CENTRAL CONUS AND SFC HIGH NEARLY STNRY OVER THE UPR
GRTLKS. THIS SHOULD PROVIDE OUR AREA WITH SEVERAL DAYS OF
STABLE/FAIR WX. WK N-NE LOW LEVEL FLOW WITH RATHER WARM MID-UPR
LEVELS SHOULD RESULT IN TEMPS NEAR NORMAL ACROSS OUR AREA DURING
THIS PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1252 AM EDT SUN MAY 18 2014
VFR MET CONDITIONS THROUGH THE ENTIRE FORECAST PERIOD. DETAIL
PROVIDED PRIMARILY FOR DIURNAL VARIANCE IN WIND SPEED/DIRECTION.
STEEPENING LOW LEVEL LAPSE RATES TO OFFER SOME CU DEVELOPMENT AND
WHILE BASES INITIALLY COULD BE AROUND 3KFT...INCREASING SURFACE
T/TD DEPRESSIONS TO AROUND 25-30F TO QUICKLY ALLOW BASES TO
LIFT ALONG WITH EROSION OF COVERAGE AS DRY AIR ENTRAINS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MURPHY
SYNOPSIS...MARSILI
SHORT TERM...SKIPPER
LONG TERM...JT
AVIATION...MURPHY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS TOPEKA KS
259 PM CDT Sun May 18 2014
.SHORT TERM...(This Evening through Monday)
Issued at 259 PM CDT SUN MAY 18 2014
19Z water vapor imagery shows an upper trough from the Hudson bay
down along the mid Atlantic seaboard with a shortwave over the mid MS
river valley. A closed low was spinning off the Pacific northwest
coast causing a low amplitude ridge to propagate east across the
Rockies and into the plains. Surface obs show a trough of low
pressure in the lee of the Rockies deepening with higher dewpoints
across the southern plains poised to move north.
For tonight and Monday, models continue to show a strong warm air
advection pattern setting up as the low level jet increases. While
low level moisture is likely to increase with the southerly winds,
models continue to show a stout elevated mixed layer (EML) advecting
in from the southwest. This dry and warm air (700MB temps around
+12C) is expected to form a capping inversion by Monday and the
latest RAP and NAM solutions have this warm air moving in as soon as
this evening. So am still not that optimistic on precip chances
overnight as the low level jet advects dryer air northeast. The RAP
and HRRR have started to show convection coming off the higher
terrain out west, but it falls apart as it runs into the EML. The
GFS is the only solution with any meaningful QPF and the forecast
soundings do not really support elevated convection as it too
advects in the EML and no real instability above the inversion.
There may be an isolated shower along the leading edge of the EML as
decent isentropic upglide provides some lift, so have continued with
some slight chance POPs for the early morning hours. By late in the
morning, the EML should be over much of the area with no real large
scale forcing to break the cap. Therefore expect Monday to remain
dry for the most part. Think the main sensible weather overnight
will be some low stratus advecting north with the moisture return.
The increasing pressure gradient should keep the boundary layer
mixed overnight so fog development appears to have a low probability
of occurring. The breezy winds and increasing low level moisture
should keep lows in the upper 50s to around 60 tonight. Good warm air
advection and afternoon sunshine should help push highs into the mid
80s to around 90.
.LONG TERM...(Monday Night through Sunday)
Issued at 259 PM CDT SUN MAY 18 2014
Medium and longer range periods looking similar to other recent
model runs. Elevated mixed layer should remain in control and keep
convection in check into the mid week periods despite a modest cold
front sinking south. Location of the low level thermal axis is
somewhat in question, but will likely poke most strongly northeast
into southwestern portions of the area Tuesday and back off the to
the southwest Wednesday with low level flow more backed, with highs
into the 90s along it. As the surface high works its way east toward
the Great Lakes, low level moisture will pool along the boundary and
low level jet pick up in intensity Wednesday night. This presents
the first notable chance for precipitation mainly in northern
Kansas. Northwest flow over the eastern CONUS brings the surface
high southeast and with help of convection, helps bring the old
front farther south into Kansas. The EML should weaken and moisten
as models are fairly consistent with precipitation becoming more
widespread in the southern High Plains and local mid level parcels
being sourced from this area. The boundary`s presence and much more
limited convective inhibition will keep precipitation chances
through much of the late week and into the weekend with temperatures
modifying back toward normal. Boundary could be rather weak to
non-existent by the weekend but models are fairly consistent with
the southwest cut-off low topping the Rockies by this time. The
Wednesday night storms could present the highest severe weather
potential when shear profiles are at least moderate, but weakening
flow should keep anything more than pulse severe storms in check for
the bulk the forecast with areas of heavier rains possible from
slow-moving convection in an atmosphere with above normal
precipitable water.
&&
.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1215 PM CDT SUN MAY 18 2014
Think VFR conditions will prevail through this evening with no
real forcing or lift to create precip or restrictions to VSBY and
CIGS. Main concern will be low level moisture return overnight and
noticed central OK is still trying to mix out some IFR CIGS. With
this moisture poised to move north overnight, will introduce some
MVFR CIGS, but confidence is still marginal since the latest RAP
soundings do not saturate the boundary layer. Because of this,
have CIGS in a TEMPO group for now. Any TS chances overnight
appear to be to small to include a mention in the terminals due to
a strengthening EML advecting in from the southwest.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...65
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS CARIBOU ME
635 PM EDT SUN MAY 18 2014
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN JUST EAST OF THE AREA INTO MONDAY
WHILE AN UPPER LOW PRESSURE SYSTEM DRIFTS SLOWLY SE THROUGH EARLY
WEEK. WEAK SURFACE HIGH PRESSURE WILL GRADUALLY BUILD INTO THE
REGION TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
635 PM UPDATE...AN UPPER LOW TO THE WEST OF THE STATE WILL MOVE
INTO NORTHERN NEW ENGLAND LATE TONIGHT WITH THE CENTER OF THE
UPPER LOW TO PASS INTO THE SOUTHERN GULF OF MAINE MONDAY. THE COLD
FRONT THAT STALLED OUT ALONG THE ME/NB BORDER LAST NIGHT REMAINS
QUASI-STATIONARY. THE FRONT IS NOW MORE OR LESS AN INVERTED TROUGH
THAT STRETCHES FROM THE GULF OF MAINE TO THE ST LAWRENCE RIVER IN
QUEBEC. THE TROUGH WILL PROVIDE THE FOCUS FOR SHOWERS ACROSS
EASTERN MAINE TONIGHT. RAINFALL AMOUNTS HAVE RANGED FROM A COUPLE
HUNDREDTHS OF AN INCH TO LOCALLY A QUARTER OF AN INCH OVER THE
PAST 3 HOURS. THE ONGOING FORECAST HAS A VERY GOOD HANDLE ON
THINGS...AND THE ONLY CHANGE IS TO BUMP UP THE POPS TO
CATEGORICAL ACROSS PARTS OF EASTERN MAINE THIS EVENING AS THE RAIN
HAS CONTINUED TO FILL IN ON THE KCBW 88-D AND MOST AREAS ARE
REPORTING -RA.
PREVIOUS DISCUSSION...
THE PRIMARY WEATHER CONCERN IN THE NEAR TERM CONTINUES TO BE THE
BOUNDARY THAT IS GENERALLY QUASI STATIONARY ALONG THE CANADIAN
BORDER. THIS BOUNDARY IS CONTINUING TO BE INFLUENCED BY THE
BLOCKING HIGH OFF TO THE EAST. THE WSR-88D INDICATES AREA OF
SHOWERS FROM PORTIONS OF NE AROOSTOOK TO EASTERN PORTIONS OF
PENOBSCOT TO WASHINGTON COUNTIES. THE HRRR GUIDANCE HAS HAD A
GREAT HANDLE ON THE PRECIP TODAY AND THIS GUIDANCE
INDICATES THAT THE PRECIP WILL CONTINUE TO FILL IN THIS AFTERNOON
AND EVENING. THIS FRONTAL BOUNDARY AND UPPER LEVEL JET ENERGY WILL
CONTINUE TO BE THE PRIMARY LIFTING MECHANISMS. THE BEST CHANCES
OF SHOWERS WILL CONTINUE TO BE ACROSS EASTERN PORTIONS OF THE
REGION IN ASSOCIATION WITH THE BOUNDARY. THIS LOW PRESSURE SYSTEM
WILL CONTINUE TO STAY QUASI-STATIONARY ACROSS REGION INTO MONDAY.
THIS COUPLED WITH WITH THE UPPER LEVEL LOW MOVING SOUTH INTO THE
GULF OF MAINE WILL KEEP THE PATTERN UNSETTLED INTO MONDAY.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
THE UPPER LEVEL LOW WILL START THIS PERIOD OFF THE NEW ENGLAND
COAST WITH AN INVERTED TROUGH REMAINING OVER THE FORECAST AREA. A
VORT MAX ASSOCIATED WITH A LOBE ROTATING AROUND THE UPPER LOW IS
EXPECTED TO CROSS THE AREA MONDAY NIGHT. THIS WILL CAUSE SHOWERS.
THE SHOWERS WILL GRADUALLY WEAKEN AND MOVE SOUTH LATER IN THE
NIGHT AS THE UPPER LOW SHIFTS SOUTHWARD. FOR TUESDAY...THE
INVERTED TROUGH WILL BE GONE AND THE SURFACE FLOW WILL SHIFT FROM
NE TO N DURING THE DAY. THIS MEANS COOL TEMPERATURES UNDER MOSTLY
CLOUDY SKIES AND A FEW LIGHT SHOWERS. TRANSITORY SURFACE AND UPPER
RIDGING BUILDS TUESDAY NIGHT INTO WEDNESDAY. THE RIDGING IS
EXPECTED TO END THE LIGHT SHOWERS TUESDAY NIGHT. HOWEVER...CLOUD
COVER CONTINUES INTO WEDNESDAY AS MOIST LOW LEVELS PERSIST. AS THE
UPPER RIDGE CROSSES MIDDAY WEDNESDAY...DAYTIME HEATING AND A
CYCLONIC FLOW MAY SPUR ANOTHER ROUND OF A FEW LIGHT AFTERNOON
SHOWERS. HIGHS DURING THE PERIOD WILL BE IN THE LOW 60S AND LOWS
WILL BE IN THE UPPER 40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE UPPER RIDGE WILL PROCEED EASTWARD WEDNESDAY NIGHT AND AN UPPER
LEVEL LOW IS PROGGED TO ARRIVE THURSDAY WITH ANOTHER ROUND OF
SHOWERS. THE GUIDANCE DIVERGES ON THURSDAY ON THE TRACK AND
EVOLUTION OF THIS UPPER LEVEL CUT OFF. WILL LEAN TOWARDS THE ECMWF
HANDLING OF THE SYSTEM WHICH BRINGS CLOUDY AND SHOWERY WEATHER
FROM THURSDAY AFTERNOON INTO SATURDAY. HIGHS WILL CONTINUE IN THE
LOWER 60S AND LOWS IN THE UPPER 40S THROUGH THIS PERIOD.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: MOSTLY VFR NORTH OF KHUL EARLY THIS EVENING WILL
DETERIORATE TO MVFR AND POSSIBLY IFR TONIGHT IN LOWER STRATUS AND
PATCHY FOG. MVFR AT KBGR WILL DETERIORATE TO IFR EARLY THIS
EVENING WITH IFR PERSISTING AT KBHB. SOME SLOW IMPROVEMENT TO
MVFR/VFR BY MON PM.
SHORT TERM: MOIST LOW LEVELS AND RAIN SHOWERS ARE EXPECTED THROUGH
MUCH OF THE PERIOD. THIS WILL RESULT IN DIURNALLY DRIVEN
CONDITIONS VARYING FROM PREVAILING IFR OR MVFR AT NIGHT INTO THE
MORNING. CEILINGS WILL GENERALLY IMPROVE TO VFR IN THE AFTERNOONS IN
LINE WITH CLIMATOLOGY.
&&
.MARINE...
NEAR TERM: NO HEADLINES EXPECTED THROUGH MONDAY. SEAS ARE RUNNING
AROUND 4 FT AT THE EASTERN MAINE SHELF...AND IS MOSTLY THE RESULT
OF RESIDUAL LONG PERIOD SWELL. THE VSBY WILL BE REDUCED TO 1/2 NM
OR LESS AT TIMES TONIGHT AND MONDAY MORNING IN FOG.
SHORT TERM: FOG WILL BE THE PRIMARY FORECAST CHALLENGE THROUGH THE
PERIOD. LIGHT WINDS AND A SOUTHERLY SWELL AROUND 2 TO 3 FEET WILL
OCCUR THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
.CLIMATE...FOR THE 2ND DAY IN A ROW A RECORD WARM LOW TEMPERATURE
RECORD WAS BROKEN AT CARIBOU. THE LOW YESTERDAY OF 55 DEGREES WAS
THE WARMEST LOW TEMP EVER OBSERVED ON MAY 17TH. THE OLD RECORD OF
54F WAS SET IN 1989.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...CB/JORDAN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...CB/JORDAN/MCW
MARINE...CB/JORDAN/MCW
CLIMATE...CB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
319 PM EDT SUN MAY 18 2014
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN JUST EAST OF THE AREA INTO MONDAY
WHILE AN UPPER LOW PRESSURE SYSTEM DRIFTS SLOWLY SE THROUGH EARLY
WEEK. WEAK SURFACE HIGH PRESSURE WILL GRADUALLY BUILD INTO THE
REGION TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
THE PRIMARY WEATHER CONCERN IN THE NEAR TERM CONTINUES TO BE THE
BOUNDARY THAT IS GENERALLY QUASI STATIONARY ALONG THE CANADIAN
BORDER. THIS BOUNDARY IS CONTINUING TO BE INFLUENCED BY THE
BLOCKING HIGH OFF TO THE EAST. THE WSR-88D INDICATES AREA OF
SHOWERS FROM PORTIONS OF NE AROOSTOOK TO EASTERN PORTIONS OF
PENOBSCOT TO WASHINGTON COUNTIES. THE HRRR GUIDANCE HAS HAD A
GREAT HANDLE ON THE PRECIP TODAY AND THIS GUIDANCE
INDICATES THAT THE PRECIP WILL CONTINUE TO FILL IN THIS AFTERNOON
AND EVENING. THIS FRONTAL BOUNDARY AND UPPER LEVEL JET ENERGY WILL
CONTINUE TO BE THE PRIMARY LIFTING MECHANISMS. THE BEST CHANCES
OF SHOWERS WILL CONTINUE TO BE ACROSS EASTERN PORTIONS OF THE
REGION IN ASSOCIATION WITH THE BOUNDARY. THIS LOW PRESSURE SYSTEM
WILL CONTINUE TO STAY QUASI-STATIONARY ACROSS REGION INTO MONDAY.
THIS COUPLED WITH WITH THE UPPER LEVEL LOW MOVING SOUTH INTO THE
GULF OF MAINE WILL KEEP THE PATTERN UNSETTLED INTO MONDAY.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
THE UPPER LEVEL LOW WILL START THIS PERIOD OFF THE NEW ENGLAND
COAST WITH AN INVERTED TROUGH REMAINING OVER THE FORECAST AREA. A
VORT MAX ASSOCIATED WITH A LOBE ROTATING AROUND THE UPPER LOW IS
EXPECTED TO CROSS THE AREA MONDAY NIGHT. THIS WILL CAUSE SHOWERS.
THE SHOWERS WILL GRADUALLY WEAKEN AND MOVE SOUTH LATER IN THE
NIGHT AS THE UPPER LOW SHIFTS SOUTHWARD. FOR TUESDAY...THE
INVERTED TROUGH WILL BE GONE AND THE SURFACE FLOW WILL SHIFT FROM
NE TO N DURING THE DAY. THIS MEANS COOL TEMPERATURES UNDER MOSTLY
CLOUDY SKIES AND A FEW LIGHT SHOWERS. TRANSITORY SURFACE AND UPPER
RIDGING BUILDS TUESDAY NIGHT INTO WEDNESDAY. THE RIDGING IS
EXPECTED TO END THE LIGHT SHOWERS TUESDAY NIGHT. HOWEVER...CLOUD
COVER CONTINUES INTO WEDNESDAY AS MOIST LOW LEVELS PERSIST. AS THE
UPPER RIDGE CROSSES MIDDAY WEDNESDAY...DAYTIME HEATING AND A
CYCLONIC FLOW MAY SPUR ANOTHER ROUND OF A FEW LIGHT AFTERNOON
SHOWERS. HIGHS DURING THE PERIOD WILL BE IN THE LOW 60S AND LOWS
WILL BE IN THE UPPER 40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
THE UPPER RIDGE WILL PROCEED EASTWARD WEDNESDAY NIGHT AND AN UPPER
LEVEL LOW IS PROGGED TO ARRIVE THURSDAY WITH ANOTHER ROUND OF
SHOWERS. THE GUIDANCE DIVERGES ON THURSDAY ON THE TRACK AND
EVOLUTION OF THIS UPPER LEVEL CUT OFF. WILL LEAN TOWARDS THE ECMWF
HANDLING OF THE SYSTEM WHICH BRINGS CLOUDY AND SHOWERY WEATHER
FROM THURSDAY AFTERNOON INTO SATURDAY. HIGHS WILL CONTINUE IN THE
LOWER 60S AND LOWS IN THE UPPER 40S THROUGH THIS PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: CONDITIONS WILL CONTINUE TO FLOAT BETWEEN MVFR AND VFR
AS CLOUDS CONTINUE TO SPREAD EAST ACROSS THE REGION THIS AFTERNOON
AND EVENING. CONDITIONS WILL CONTINUE TO DETERIORATE OVERNIGHT AND
COME BACK UP MVFR/VFR FOR SITES ON LATER ON MONDAY.
SHORT TERM: MOIST LOW LEVELS AND RAIN SHOWERS ARE EXPECTED THROUGH
MUCH OF THE PERIOD. THIS WILL RESULT IN DIURNALLY DRIVEN
CONDITIONS VARYING FROM PREVAILING IFR OR MVFR AT NIGHT INTO THE
MORNING. CEILINGS WILL GENERALLY IMPROVE TO VFR IN THE AFTERNOONS IN
LINE WITH CLIMATOLOGY.
&&
.MARINE...
NEAR TERM: NO HEADLINES EXPECTED THROUGH THE NEAR TERM PERIOD WITH
LIGHT WINDS AND SEAS GENERALLY 2 TO 4 FT.
SHORT TERM: FOG WILL BE THE PRIMARY FORECAST CHALLENGE THROUGH THE
PERIOD. LIGHT WINDS AND A SOUTHERLY SWELL AROUND 2 TO 3 FEET WILL
OCCUR THROUGH THE PERIOD. &&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JORDAN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...JORDAN/MCW
MARINE...JORDAN/MCW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
127 PM EDT SUN MAY 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM EDT SUN MAY 18 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A TROUGH INTO THE ERN LAKES AND
A RIDGE OVER THE WRN PLAINS. A WEAK SHORTWAVE TROUGH INTO WRN UPPER
MI AND NW WI SUPPORTED LITTLE MORE THAN MID CLOUDS AND A FEW
SPRINKLES. ANOTHER UPSTREAM SHRTWV WAS LOCATED OVER SRN MANITOBA. AT
THE SFC...LIGHT SW WINDS PREVAILED AHEAD OF A WEAK TROUGH/FRONT FROM
NEAR CYGQ(GERALDTON) TO NW MN.
TODAY...EXPECT THE MANITOBA SHRTWV AND ASSOCIATED WEAK MID LEVEL
QVECTOR CONV TO MOVE INTO UPPER MI BY THIS AFTERNOON. MODELS HAVE
BEEN CONSISTENT IN SUGGESTING THAT THERE WILL BE ENOUGH FORCING AND WEAK
ISENTROPIC LIFT WITH THE SHRTWV TO GENERATE SOME LIGHT PCPN. DIURNAL
HEATING WITH MODERATELY STEEP MID LEVEL LAPSE RATES AROUND 7 C/KM
SHOULD ALSO BOOST SHRA POTENTIAL. ALTHOUGH MOISTURE AVAILABILITY
WILL BE LIMITED...AT LEAST LOW END CHANCE POPS ARE WARRANTED. MIXING
TO 850 MB TEMPS IN THE 5C TO 7C RANGE SUPPORTS HIGHS IN THE LOW TO
MID 60S. LAKE BREEZES WILL KEEP READINGS IN THE 50S ALONG SHORELINE
LOCATIONS.
TONIGHT...EXPECT ANY LINGERING LIGHT SHOWERS OVER THE CENTRAL AND
SOUTHEAST TO DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME
HEATING. UNDERT CLEAR TO PARTLY CLOUDY SKIES...INCREASING SW WINDS
WILL BE STRONG ENOUGH TO PROVIDE SOME MIXING AND KEEP MIN TEMPS IN
THE LOWER TO MID 40S WEST AND THE THE UPPER 30S OVER THE ERN CWA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 511 AM EDT SUN MAY 18 2014
WILL CONCENTRATE THIS DISCUSSION ON THE HIGHEST IMPACT FOR THIS
PERIOD...AND THAT WILL BE WITH THE SFC LOW TRACKING FROM THE DAKOTAS
AT 00Z TUESDAY AND THE LOCATION OF UPPER MI IN BETWEEN IT AND THE
EXITING SFC HIGH OVER THE LOWER GREAT LAKES.
EXPECT THE LOW PRESSURE SYSTEM TO CROSS UPPER MICHIGAN ON
TUESDAY...WITH SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WEST AND
CENTRAL LATE MONDAY AFTERNOON AND MONDAY EVENING. SHOWERS AND
THUNDERSTORMS WILL EXPAND ACROSS EASTERN UPPER MICHIGAN MONDAY NIGHT
AND RESIDE ACROSS MAINLY EASTERN AREAS DURING THE DAY TUESDAY. THE
LOW PRESSURE SYSTEM WILL SLOWLY EXIT EAST ON WEDNESDAY...WITH MAINLY
DRY WEATHER WEDNESDAY THROUGH THE REST OF THE WORK WEEK.
OF COURSE SPECIFIC QPF ESTIMATES IN CONVECTIVE WEATHER IS VERY
DIFFICULT...AND HIGHLY DEPENDS ON TIMING/COVERAGE/LOCATIONS OF
ANY THUNDERSTORM ACTIVITY. BEST CHANCE OF MODERATE RAINFALL WILL
LIKELY BE MONDAY EVENING WEST...AND OVERNIGHT ACROSS CENTRAL UPPER
MI. FCST MODELS ARE CONSISTENT WITH THE IDEA OF NEARLY 0.5IN CWA
WIDE OVERNIGHT. THIS EQUATES TO QPF VALUES OF 0.7 TO 1IN ACROSS MUCH
OF THE CWA FROM LATE MONDAY AFTERNOON THROUGH TUESDAY EVENING. WILL
BE INTERESTED IN SEEING HOW SOME OF THE RIVERS THAT ARE AREA.THERE
WILL BE A SLIGHT CHANCE FOR THUNDERSTORMS OVER W AND CENTRAL AREAS
BY LATE TUESDAY MORNING...EXTENDING ACROSS THE REMAINDER OF THE CWA
THROUGH TUESDAY EVENING BEFORE COMING TO AN END.
MAINLY DRY WEATHER CAN BE EXPECTED WEDNESDAY THROUGH SATURDAY...IN
RESPONSE TO THE HUDSON BAY HIGH EXTENDING DOWN THROUGH THE UPPER
GREAT LAKES AND 500MB RIDGE BUILDING OVERHEAD. WHILE HIGH
TEMPERATURES WILL REBOUND BACK TO NORMAL OR SLIGHTLY ABOVE NORMAL
FOR THE END OF THE WORK WEEK AND START OF THE WEEKEND LOWER HUMIDITY
VALUES COULD RAISE SOME CONCERNS WITH REGARD TO FIRE WEATHER. THE
GOOD NEWS AT THIS POINT IS THAT WINDS SHOULD REMAIN LIGHT WITH THE
SFC HIGH OVERHEAD...SO CONCERNS WILL REMAIN MINIMAL AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 125 PM EDT SUN MAY 18 2014
BEST CHANCE OF PRECIP TODAY IS AT KSAW WHERE SCATTERED SHOWERS ARE
NEAR EARLY THIS AFTERNOON. SHOWERS WILL DIMINISH THIS EVENING DUE TO
LOSS OF DAYTIME HEATING. CLOUD BASES WILL BE HIGH DUE TO VERY DRY
LOW LEVEL AIR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT SAT MAY 17 2014
WINDS WILL BE UNDER 20KT THROUGHOUT MOST OF THE FORECAST. LOW
PRESSURE DEVELOPING OVER THE PLAINS EARLY NEXT WEEK WILL MOVE ACROSS
NORTHERN LAKE SUPERIOR BEGINNING LATE MONDAY NIGHT THROUGH EARLY
WEDNESDAY...WHICH WILL PRODUCE AN INCREASE IN THE WINDS. WINDS
SPEEDS TO AROUND 20 KNOTS MAY OCCUR FOR A TIME OVER CENTRAL AND
EASTERN LAKE SUPERIOR AHEAD OF THE SURFACE LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 AM EDT SUN MAY 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM EDT SUN MAY 18 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A TROUGH INTO THE ERN LAKES AND
A RIDGE OVER THE WRN PLAINS. A WEAK SHORTWAVE TROUGH INTO WRN UPPER
MI AND NW WI SUPPORTED LITTLE MORE THAN MID CLOUDS AND A FEW
SPRINKLES. ANOTHER UPSTREAM SHRTWV WAS LOCATED OVER SRN MANITOBA. AT
THE SFC...LIGHT SW WINDS PREVAILED AHEAD OF A WEAK TROUGH/FRONT FROM
NEAR CYGQ(GERALDTON) TO NW MN.
TODAY...EXPECT THE MANITOBA SHRTWV AND ASSOCIATED WEAK MID LEVEL
QVECTOR CONV TO MOVE INTO UPPER MI BY THIS AFTERNOON. MODELS HAVE
BEEN CONSISTENT IN SUGGESTING THAT THERE WILL BE ENOUGH FORCING AND WEAK
ISENTROPIC LIFT WITH THE SHRTWV TO GENERATE SOME LIGHT PCPN. DIURNAL
HEATING WITH MODERATELY STEEP MID LEVEL LAPSE RATES AROUND 7 C/KM
SHOULD ALSO BOOST SHRA POTENTIAL. ALTHOUGH MOISTURE AVAILABILITY
WILL BE LIMITED...AT LEAST LOW END CHANCE POPS ARE WARRANTED. MIXING
TO 850 MB TEMPS IN THE 5C TO 7C RANGE SUPPORTS HIGHS IN THE LOW TO
MID 60S. LAKE BREEZES WILL KEEP READINGS IN THE 50S ALONG SHORELINE
LOCATIONS.
TONIGHT...EXPECT ANY LINGERING LIGHT SHOWERS OVER THE CENTRAL AND
SOUTHEAST TO DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME
HEATING. UNDERT CLEAR TO PARTLY CLOUDY SKIES...INCREASING SW WINDS
WILL BE STRONG ENOUGH TO PROVIDE SOME MIXING AND KEEP MIN TEMPS IN
THE LOWER TO MID 40S WEST AND THE THE UPPER 30S OVER THE ERN CWA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 511 AM EDT SUN MAY 18 2014
WILL CONCENTRATE THIS DISCUSSION ON THE HIGHEST IMPACT FOR THIS
PERIOD...AND THAT WILL BE WITH THE SFC LOW TRACKING FROM THE DAKOTAS
AT 00Z TUESDAY AND THE LOCATION OF UPPER MI IN BETWEEN IT AND THE
EXITING SFC HIGH OVER THE LOWER GREAT LAKES.
EXPECT THE LOW PRESSURE SYSTEM TO CROSS UPPER MICHIGAN ON
TUESDAY...WITH SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WEST AND
CENTRAL LATE MONDAY AFTERNOON AND MONDAY EVENING. SHOWERS AND
THUNDERSTORMS WILL EXPAND ACROSS EASTERN UPPER MICHIGAN MONDAY NIGHT
AND RESIDE ACROSS MAINLY EASTERN AREAS DURING THE DAY TUESDAY. THE
LOW PRESSURE SYSTEM WILL SLOWLY EXIT EAST ON WEDNESDAY...WITH MAINLY
DRY WEATHER WEDNESDAY THROUGH THE REST OF THE WORK WEEK.
OF COURSE SPECIFIC QPF ESTIMATES IN CONVECTIVE WEATHER IS VERY
DIFFICULT...AND HIGHLY DEPENDS ON TIMING/COVERAGE/LOCATIONS OF
ANY THUNDERSTORM ACTIVITY. BEST CHANCE OF MODERATE RAINFALL WILL
LIKELY BE MONDAY EVENING WEST...AND OVERNIGHT ACROSS CENTRAL UPPER
MI. FCST MODELS ARE CONSISTENT WITH THE IDEA OF NEARLY 0.5IN CWA
WIDE OVERNIGHT. THIS EQUATES TO QPF VALUES OF 0.7 TO 1IN ACROSS MUCH
OF THE CWA FROM LATE MONDAY AFTERNOON THROUGH TUESDAY EVENING. WILL
BE INTERESTED IN SEEING HOW SOME OF THE RIVERS THAT ARE AREA.THERE
WILL BE A SLIGHT CHANCE FOR THUNDERSTORMS OVER W AND CENTRAL AREAS
BY LATE TUESDAY MORNING...EXTENDING ACROSS THE REMAINDER OF THE CWA
THROUGH TUESDAY EVENING BEFORE COMING TO AN END.
MAINLY DRY WEATHER CAN BE EXPECTED WEDNESDAY THROUGH SATURDAY...IN
RESPONSE TO THE HUDSON BAY HIGH EXTENDING DOWN THROUGH THE UPPER
GREAT LAKES AND 500MB RIDGE BUILDING OVERHEAD. WHILE HIGH
TEMPERATURES WILL REBOUND BACK TO NORMAL OR SLIGHTLY ABOVE NORMAL
FOR THE END OF THE WORK WEEK AND START OF THE WEEKEND LOWER HUMIDITY
VALUES COULD RAISE SOME CONCERNS WITH REGARD TO FIRE WEATHER. THE
GOOD NEWS AT THIS POINT IS THAT WINDS SHOULD REMAIN LIGHT WITH THE
SFC HIGH OVERHEAD...SO CONCERNS WILL REMAIN MINIMAL AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 737 AM EDT SUN MAY 18 2014
EXPECT VFR CONDITIONS AND LIGHT WINDS TO PREVAIL THIS FCST PERIOD
WITH DRY HIGH PRES DOMINATING. ALTHOUGH THE PASSAGE OF A WEAK
DISTURBANCE MAY BRING A FEW INSTABILITY -SHRA TODAY DURING DAYTIME
HEATING...OVERALL DRYNESS OF THE AIRMASS/HIGH LCLS WILL ENSURE VFR
CONDITIONS EVEN IF THE ISOLD -SHRA IMPACT ANY OF THE SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT SAT MAY 17 2014
WINDS WILL BE UNDER 20KT THROUGHOUT MOST OF THE FORECAST. LOW
PRESSURE DEVELOPING OVER THE PLAINS EARLY NEXT WEEK WILL MOVE ACROSS
NORTHERN LAKE SUPERIOR BEGINNING LATE MONDAY NIGHT THROUGH EARLY
WEDNESDAY...WHICH WILL PRODUCE AN INCREASE IN THE WINDS. WINDS
SPEEDS TO AROUND 20 KNOTS MAY OCCUR FOR A TIME OVER CENTRAL AND
EASTERN LAKE SUPERIOR AHEAD OF THE SURFACE LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
511 AM EDT SUN MAY 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM EDT SUN MAY 18 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A TROUGH INTO THE ERN LAKES AND
A RIDGE OVER THE WRN PLAINS. A WEAK SHORTWAVE TROUGH INTO WRN UPPER
MI AND NW WI SUPPORTED LITTLE MORE THAN MID CLOUDS AND A FEW
SPRINKLES. ANOTHER UPSTREAM SHRTWV WAS LOCATED OVER SRN MANITOBA. AT
THE SFC...LIGHT SW WINDS PREVAILED AHEAD OF A WEAK TROUGH/FRONT FROM
NEAR CYGQ(GERALDTON) TO NW MN.
TODAY...EXPECT THE MANITOBA SHRTWV AND ASSOCIATED WEAK MID LEVEL
QVECTOR CONV TO MOVE INTO UPPER MI BY THIS AFTERNOON. MODELS HAVE
BEEN CONSISTENT IN SUGGESTING THAT THERE WILL BE ENOUGH FORCING AND WEAK
ISENTROPIC LIFT WITH THE SHRTWV TO GENERATE SOME LIGHT PCPN. DIURNAL
HEATING WITH MODERATELY STEEP MID LEVEL LAPSE RATES AROUND 7 C/KM
SHOULD ALSO BOOST SHRA POTENTIAL. ALTHOUGH MOISTURE AVAILABILITY
WILL BE LIMITED...AT LEAST LOW END CHANCE POPS ARE WARRANTED. MIXING
TO 850 MB TEMPS IN THE 5C TO 7C RANGE SUPPORTS HIGHS IN THE LOW TO
MID 60S. LAKE BREEZES WILL KEEP READINGS IN THE 50S ALONG SHORELINE
LOCATIONS.
TONIGHT...EXPECT ANY LINGERING LIGHT SHOWERS OVER THE CENTRAL AND
SOUTHEAST TO DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME
HEATING. UNDERT CLEAR TO PARTLY CLOUDY SKIES...INCREASING SW WINDS
WILL BE STRONG ENOUGH TO PROVIDE SOME MIXING AND KEEP MIN TEMPS IN
THE LOWER TO MID 40S WEST AND THE THE UPPER 30S OVER THE ERN CWA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 511 AM EDT SUN MAY 18 2014
WILL CONCENTRATE THIS DISCUSSION ON THE HIGHEST IMPACT FOR THIS
PERIOD...AND THAT WILL BE WITH THE SFC LOW TRACKING FROM THE DAKOTAS
AT 00Z TUESDAY AND THE LOCATION OF UPPER MI IN BETWEEN IT AND THE
EXITING SFC HIGH OVER THE LOWER GREAT LAKES.
EXPECT THE LOW PRESSURE SYSTEM TO CROSS UPPER MICHIGAN ON
TUESDAY...WITH SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WEST AND
CENTRAL LATE MONDAY AFTERNOON AND MONDAY EVENING. SHOWERS AND
THUNDERSTORMS WILL EXPAND ACROSS EASTERN UPPER MICHIGAN MONDAY NIGHT
AND RESIDE ACROSS MAINLY EASTERN AREAS DURING THE DAY TUESDAY. THE
LOW PRESSURE SYSTEM WILL SLOWLY EXIT EAST ON WEDNESDAY...WITH MAINLY
DRY WEATHER WEDNESDAY THROUGH THE REST OF THE WORK WEEK.
OF COURSE SPECIFIC QPF ESTIMATES IN CONVECTIVE WEATHER IS VERY
DIFFICULT...AND HIGHLY DEPENDS ON TIMING/COVERAGE/LOCATIONS OF
ANY THUNDERSTORM ACTIVITY. BEST CHANCE OF MODERATE RAINFALL WILL
LIKELY BE MONDAY EVENING WEST...AND OVERNIGHT ACROSS CENTRAL UPPER
MI. FCST MODELS ARE CONSISTENT WITH THE IDEA OF NEARLY 0.5IN CWA
WIDE OVERNIGHT. THIS EQUATES TO QPF VALUES OF 0.7 TO 1IN ACROSS MUCH
OF THE CWA FROM LATE MONDAY AFTERNOON THROUGH TUESDAY EVENING. WILL
BE INTERESTED IN SEEING HOW SOME OF THE RIVERS THAT ARE AREA.THERE
WILL BE A SLIGHT CHANCE FOR THUNDERSTORMS OVER W AND CENTRAL AREAS
BY LATE TUESDAY MORNING...EXTENDING ACROSS THE REMAINDER OF THE CWA
THROUGH TUESDAY EVENING BEFORE COMING TO AN END.
MAINLY DRY WEATHER CAN BE EXPECTED WEDNESDAY THROUGH SATURDAY...IN
RESPONSE TO THE HUDSON BAY HIGH EXTENDING DOWN THROUGH THE UPPER
GREAT LAKES AND 500MB RIDGE BUILDING OVERHEAD. WHILE HIGH
TEMPERATURES WILL REBOUND BACK TO NORMAL OR SLIGHTLY ABOVE NORMAL
FOR THE END OF THE WORK WEEK AND START OF THE WEEKEND LOWER HUMIDITY
VALUES COULD RAISE SOME CONCERNS WITH REGARD TO FIRE WEATHER. THE
GOOD NEWS AT THIS POINT IS THAT WINDS SHOULD REMAIN LIGHT WITH THE
SFC HIGH OVERHEAD...SO CONCERNS WILL REMAIN MINIMAL AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 122 AM EDT SUN MAY 18 2014
EXPECT VFR CONDITIONS AND LIGHT WINDS TO PREVAIL THIS FCST PERIOD
WITH DRY HI PRES DOMINATING. ALTHOUGH THE PASSAGE OF A WEAK
DISTURBANCE MAY BRING A FEW INSTABILITY -SHRA TODAY DURING DAYTIME
HEATING...OVERALL DRYNESS OF THE AIRMASS/HI LCLS WL ENSURE VFR WX
EVEN IF THE ISOLD -SHRA IMPACT ANY OF THE SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT SAT MAY 17 2014
WINDS WILL BE UNDER 20KT THROUGHOUT MOST OF THE FORECAST. LOW
PRESSURE DEVELOPING OVER THE PLAINS EARLY NEXT WEEK WILL MOVE ACROSS
NORTHERN LAKE SUPERIOR BEGINNING LATE MONDAY NIGHT THROUGH EARLY
WEDNESDAY...WHICH WILL PRODUCE AN INCREASE IN THE WINDS. WINDS
SPEEDS TO AROUND 20 KNOTS MAY OCCUR FOR A TIME OVER CENTRAL AND
EASTERN LAKE SUPERIOR AHEAD OF THE SURFACE LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
500 AM EDT SUN MAY 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM EDT SUN MAY 18 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A TROUGH INTO THE ERN LAKES AND
A RIDGE OVER THE WRN PLAINS. A WEAK SHORTWAVE TROUGH INTO WRN UPPER
MI AND NW WI SUPPORTED LITTLE MORE THAN MID CLOUDS AND A FEW
SPRINKLES. ANOTHER UPSTREAM SHRTWV WAS LOCATED OVER SRN MANITOBA. AT
THE SFC...LIGHT SW WINDS PREVAILED AHEAD OF A WEAK TROUGH/FRONT FROM
NEAR CYGQ(GERALDTON) TO NW MN.
TODAY...EXPECT THE MANITOBA SHRTWV AND ASSOCIATED WEAK MID LEVEL
QVECTOR CONV TO MOVE INTO UPPER MI BY THIS AFTERNOON. MODELS HAVE
BEEN CONSISTENT IN SUGGESTING THAT THERE WILL BE ENOUGH FORCING AND WEAK
ISENTROPIC LIFT WITH THE SHRTWV TO GENERATE SOME LIGHT PCPN. DIURNAL
HEATING WITH MODERATELY STEEP MID LEVEL LAPSE RATES AROUND 7 C/KM
SHOULD ALSO BOOST SHRA POTENTIAL. ALTHOUGH MOISTURE AVAILABILITY
WILL BE LIMITED...AT LEAST LOW END CHANCE POPS ARE WARRANTED. MIXING
TO 850 MB TEMPS IN THE 5C TO 7C RANGE SUPPORTS HIGHS IN THE LOW TO
MID 60S. LAKE BREEZES WILL KEEP READINGS IN THE 50S ALONG SHORELINE
LOCATIONS.
TONIGHT...EXPECT ANY LINGERING LIGHT SHOWERS OVER THE CENTRAL AND
SOUTHEAST TO DIMINISH DURING THE EVENING WITH THE LOSS OF DAYTIME
HEATING. UNDERT CLEAR TO PARTLY CLOUDY SKIES...INCREASING SW WINDS
WILL BE STRONG ENOUGH TO PROVIDE SOME MIXING AND KEEP MIN TEMPS IN
THE LOWER TO MID 40S WEST AND THE THE UPPER 30S OVER THE ERN CWA.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 456 PM EDT SAT MAY 17 2014
SUN NIGHT INTO MON MORNING...LINGERING LOW-LVL MOISTURE AND WEAK
295K ISENTROPIC ASCENT WILL CONTINUE TO SUPPORT SOME SCT SHRA OVER
MAINLY THE ERN FCST AREA SUNDAY EVENING BUT MID-LVL RIDGING SHOULD
RESULT IN DRY CONDITIONS OVERNIGHT INTO MON MORNING. EXPECT LOWS
FROM THE UPPER 30S EAST TO LOWER TO MID 40S FAR WEST.
MON AFTERNOON THROUGH TUE NIGHT...MODELS IN FAIRLY GOOD AGREEMENT
WITH A SHORTWAVE TROUGH LIFTING NORTH THROUGH NORTH DAKOTA/MINNESOTA
INTO SRN MANITOBA TO NRN ONTARIO WHICH WILL BRING AN 850 MB WARM
FRONT THROUGH THE NRN GREAT LAKES. 300K-305K ISENTROPIC LIFT AHEAD
OF THE FRONT WITH STRONG MOISTURE INFLOW (PWAT TO 1.25 INCH OR MORE
THAN 175 PCT OF NORMAL) AT NOSE OF 40-45 KNOT LOW-LVL JET WILL
SUPPORT LIKELY TO CATEGORICAL POPS AND POTENTIAL FOR MODERATE
RAINFALL AMOUNTS IN THE 0.50-0.75 INCH RANGE. MODELS INDICATE RAIN
WILL MOVE INTO WEST HALF OF UPPER MI BY LATE AFTERNOON SPREADING
INTO THE EAST HALF MON NIGHT. WITH TRANSITION TO ISENTROPIC DESCENT
EXPECT RAIN TO TAPER OFF FROM WEST TO EAST THROUGH TUE WITH
LINGERING SHOWERS TUE EVENING EAST HALF. HAVE ONLY SLIGHT CHANCE FOR
TSRA ALONG THE WI BDR MON NIGHT WITH THUNDER CHANCES SPREADING WEST
TO EAST ACROSS THE AREA LATE MON NIGHT INTO TUESDAY WITH A POCKET OF
200-400 J/KG MUCAPE.
WED-SAT...MAINLY DRY WEATHER IS EXPECTED AS A CONFLUENT MID LEVEL
FLOW DEVELOPS AND HIGH PRES BUILDS INTO THE REGION. HIGH TEMPS MAY
START OUT BELOW NORMAL FOR MIDWEEK WITH A STIFF NRLY FLOW OFF LAKE
SUPERIOR BETWEEN DEPARTING LOW PRES EAST OF THE LAKE AND HIGH PRES
BUILDING IN FM THE NW. BY THE END OF THE WEEK HOWEVER...HIGH TEMPS
SHOULD REBOUND NEAR SEASONAL NORMALS...IN THE LOWER TO MID 60S.
LIGHT NRLY FLOW WILL CONTINUE TO KEEP READINGS IN THE LOWER 50S NEAR
LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 122 AM EDT SUN MAY 18 2014
EXPECT VFR CONDITIONS AND LIGHT WINDS TO PREVAIL THIS FCST PERIOD
WITH DRY HI PRES DOMINATING. ALTHOUGH THE PASSAGE OF A WEAK
DISTURBANCE MAY BRING A FEW INSTABILITY -SHRA TODAY DURING DAYTIME
HEATING...OVERALL DRYNESS OF THE AIRMASS/HI LCLS WL ENSURE VFR WX
EVEN IF THE ISOLD -SHRA IMPACT ANY OF THE SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT SAT MAY 17 2014
WINDS WILL BE UNDER 20KT THROUGHOUT MOST OF THE FORECAST. LOW
PRESSURE DEVELOPING OVER THE PLAINS EARLY NEXT WEEK WILL MOVE ACROSS
NORTHERN LAKE SUPERIOR BEGINNING LATE MONDAY NIGHT THROUGH EARLY
WEDNESDAY...WHICH WILL PRODUCE AN INCREASE IN THE WINDS. WINDS
SPEEDS TO AROUND 20 KNOTS MAY OCCUR FOR A TIME OVER CENTRAL AND
EASTERN LAKE SUPERIOR AHEAD OF THE SURFACE LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...VOSS
AVIATION...KC
MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
933 PM CDT Mon May 19 2014
.UPDATE:
Issued at 930 PM CDT Mon May 19 2014
Only minor changes needed to going forecasts, primarily to tweak
latest sky trends. Forecast for tonight will remain dry, but
obviously with the FA on the fringes of the westerlies we will
need to keep an eye out overnight for subtle clues to potential
development. One area of potential concern is any development that
could occur in low level convergence near boundary over se NE,
which has been hinted at by the HRRR over the last few hours. It
this were to occur, some of this activity could clip extreme
northern areas during the predawn hours. The second...and even
more subtle...area is over eastern areas very late tonight as
shortwave brushes area of low level WAA and moisture convergence
leading to an outside chance of elevated development in situ (ie:
sunrise surprise). While both scenarios bear watching, not seeing
clear enough signals in either the latest UA data and/or short
range guidance and forecast soundings to include any mention of
precip.
Truett
&&
.SHORT TERM: (Through Late Tonight)
Issued at 350 PM CDT Mon May 19 2014
Strong pressure gradient between the high over the eastern seaboard
and low pressure over western Kansas is causing strong winds across
the area this afternoon. Should see gusts diminish this evening
after we lose daytime heating, and overall surface winds will also
diminish as the surface low fills in a bit and the high over the
east coast dips south causing the pressure gradient to slacken.
However, all short range models show weak to moderate moisture
convergence over the area on the nose of the low level jet which
will ramp up to 40-50kts overnight. The GFS does spit out a few
spotty hundredths of precip, but it`s the outlier. Have kept below
mention PoPs overnight. Should see temperatures continuing to
moderate with lows pretty much universally in the low to mid 60s
across the area.
Carney
.LONG TERM: (Tuesday through Next Monday)
Issued at 350 PM CDT Mon May 19 2014
(Tuesday - Sunday)
Above average temps will prevail early in this period, then slip
back closer to normal for late week and into next weekend. A
persistent chance for thunderstorms will exist from Wednesday on.
An upper level ridge will build into the Mid-MS Valley by Tuesday in
response to a strong Pacific storm system digging into the
southwestern CONUS. This will lead to a period of above average
temps for our region. In addition, a series of upper level
disturbances will begin to ripple on through along the ridge`s
periphery. At first, moisture will be somewhat limited, the cap too
strong, and there will be the lack of a surface boundary, with the
nearest synoptic front to our north. Pcpn chances Tuesday and
Tuesday night look too low for a mentionable chance but it looks
close for a time Tuesday morning for the STL metro and surrounding
areas and again late on Tuesday night in northern MO and central IL.
By Wednesday, as a cold front drops into northern MO and central IL,
there should be sufficient elements in place to begin the chance for
TSRA and expand this chance to the rest of the forecast area late
Wednesday afternoon or night. The presence of the slowly southward
moving front...and persistent upper level disturbances will maintain
chances for TSRA thru late week and, to some extent, into the
weekend, although it will be important to note that PoPs by this
time will be below climatological values, despite being mentioned.
(Next Monday)
Still a lot of questions left unanswered as we head out into next
week with the fate of the powerful storm system in the Southwest.
The EC wants to push it into the northern High Plains while the GFS
keeps it over OK. The one commonality is that this system pushes
another disturbance, while either bucking the surface front back to
the north or dissolving it altogether, keeping pcpn chances out
until just beyond this period.
Temps push back to above normal with the resultant southerly flow.
TES
&&
.AVIATION: (For the 00z TAFs through 00z Tuesday Evening)
Issued at 647 PM CDT Mon May 19 2014
We will remain in warm sector through forecast period with gusty
south winds diminishing just after sunset. Decent low level jet
setting up over central MO, so kept mention of LLWS for KCOU after
06z. Then by mid morning on Tuesday, winds mix down to surface
with gusty south winds once again. VFR conditions to persist.
Specifics for KSTL:
We will remain in warm sector through forecast period with gusty
south winds diminishing just after sunset. Decent low level jet
setting up over central MO, but should remain west of metro area,
so did not add mention of LLWS at this time. Then by 15Z Tuesday,
winds mix down to surface with gusty south winds once again. VFR
conditions to persist.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
219 PM MDT SUN MAY 18 2014
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY...
SYSTEM MOVING THROUGH THIS AFTERNOON AND TONIGHT IS WORKING OUT AS
PLANNED. HRRR MODEL SHOWING THUNDERSTORMS TO FORM IN A QUASI-LINEAR
FASHION AND TO MOVE NORTHEAST THROUGH THE CWA LATER THIS
AFTERNOON/EVENING. THIS IS FURTHER NORTH THAN WHAT YESTERDAY/S
MODELS DEPICTED. OUTFLOW WINDS...BRIEF HEAVY RAIN AND SMALL HAIL
SEEM TO BE THE MAIN THREATS. NAM AND GFS ARE SHOWING 6 HOUR QPF
BULLS EYES NEAR AN INCH FOR TONIGHT SO WILL KEEP WORDING OF HEAVY
RAIN GOING. DO NOT EXPECT FLASH FLOODING BUT IT WILL BE A SLOPPY
MESS IN MOST AREAS COME MONDAY MORNING. DRIER CONDITIONS WILL MOVE
IN FROM THE SOUTHWEST LATE TONIGHT WITH ALL BUT THE NE ZONES DRY
MONDAY MORNING.
ON MONDAY...NAM/GFS IN AGREEMENT WITH SYSTEM BECOMING STACKED OVER S
SASK. CLEARING MAY MAKE IT NORTH INTO THE SOUTHERN ZONES...BUT
PROXIMITY TO STORM WILL KEEP NORTHERN ZONES CLOUDY WITH SCATTERED
SHOWERS. IT WILL BE WINDY TOO...SO A LAKE WIND ADVISORY LOOKS LIKELY.
MONDAY NIGHT AND TUESDAY...CLOSED SYSTEM GRADUALLY DRIFTS INTO
NORTHERN MINNESOTA. RESIDUAL MOISTURE WILL KEEP SKIES MAINLY CLOUDY
SCATTERED LIGHT SHOWERS ACROSS THE NORTH. WINDS SHOULD BE LIGHT AND
TEMPERATURES WILL BE SIMILAR TO MONDAY...SLIGHTLY BELOW NORMAL. TFJ
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
A SHORTWAVE MONDAY NIGHT INTO TUESDAY WILL BRING CHANCES FOR
SHOWERS AND THUNDERSTORMS. THEN...IT LOOKS LIKE TUESDAY NIGHT INTO
WEDNESDAY WILL BE BETWEEN SYSTEMS AND MAINLY DRY.
AN UPPER TROUGH WILL REMAIN QUASI-STATIONARY OVER THE WESTERN US
MOST OF THE WEEK. SW FLOW ALOFT FROM THIS TROUGH WILL MOVE INTO EASTERN
MONTANA ON WEDNESDAY AND REMAIN OVER THE AREA UNTIL SATURDAY.
THIS WILL BRING FREQUENT SHORTWAVES WITH UNSTABLE CONDITIONS INTO
THE FORECAST AREA WITH SLIGHT CHANCE TO CHANCE OF SHOWERS AND/OR
THUNDERSTORMS MOST OF THE PERIOD. AT THE SAME TIME...THE SW FLOW
ALOFT WILL BRING A WARMING TREND THROUGH THE WEEK.
A SHORTWAVE TROUGH MOVING INLAND FROM THE PACIFIC ON FRIDAY WILL
MOVE ACROSS MONTANA ON SATURDAY AND TURN THE FLOW ALOFT MORE
ZONAL THAT WILL CONTINUE INTO NEXT SUNDAY. CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL CONTINUE. FORRESTER
&&
.AVIATION...
FLIGHT CATEGORY: VFR MOST OF THE TIME. VARIABLE FLIGHT CONDITIONS
(IFR/MVFR/VFR) AT TIMES LATE THIS EVENING AND TONIGHT DUE TO
SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS WITH GUSTY/ERRATIC WINDS...HAIL AND/OR HEAVY RAIN
POSSIBILITIES INCREASE THROUGH THE DAY WITH MVFR/BRIEF AND LOCAL
IFR CONDITIONS POSSIBLE TONIGHT. THE RAIN CHANCES WILL DIMINISH
LATE TONIGHT OR MONDAY MORNING.
WINDS: EAST TO SOUTHEAST WILL INCREASE TO 15 KTS BY AFTERNOON. THE
WINDS WILL BACK TO THE NORTHEAST...NORTH AND EVENTUALLY NORTHWEST
TO WEST TONIGHT AS A SURFACE LOW PRESSURE SYSTEM MOVES THROUGH
EASTERN MONTANA. WEST WIND OF 15 TO 30 KTS ARE POSSIBLE AFTER 15Z.
FRANSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
734 PM CDT MON MAY 19 2014
.SYNOPSIS...
ISSUED AT 305 PM CDT MON MAY 19 2014
H5 ANALYSIS FROM THIS MORNING IS INDICATING A BROAD LOW AMPLITUDE
RIDGE ACROSS THE UPPER MISSISSIPPI VALLEY. FURTHER WEST...A STRONG
SHORTWAVE WAS PUSHING ON SHORE ALONG THE WASHINGTON AND OREGON
COASTS. HT FALLS WERE MOST PRONOUNCED OVER WYOMING AND EASTERN MT
WITH 40 TO 50 METER FALLS NOTED. FURTHER SOUTH AND EAST...WEAK HT
FALLS OF 10 TO 30 METERS WERE NOTED FROM WESTERN NEBRASKA INTO
WESTERN SOUTH DAKOTA AND CENTRAL NORTH DAKOTA. AT THE SURFACE...LOW
PRESSURE WAS NOTED OVER NRN SD AND NORTH CENTRAL KS. A FRONTAL
BOUNDARY EXTENDED ACROSS CENTRAL NEBRASKA. EAST OF THIS
FEATURE...WINDS WERE SOUTHERLY WITH NORTHERLY WINDS NOTED WEST OF
THIS FEATURE. A DRYLINE EXTENDED FROM JUST EAST OF IMPERIAL...NNWD
INTO THE NORTHERN NEBRASKA PANHANDLE. DEW POINTS EAST OF THIS
FEATURE WERE IN THE MIDDLE TO UPPER 50S...WHILE WEST OF THIS
FEATURE...DEW POINTS WERE IN THE 40S. RADAR IMAGERY AS OF 2 PM
CDT...SHOWS SOME NICE RETURNS BEGINNING TO DEVELOP INVOF THE I25
CORRIDOR IN EASTERN WYOMING...FROM NORTH OF CHEYENNE TO SOUTHEAST OF
DOUGLAS. OTHER ECHOES WERE NOTED OVER THE NORTHERN NEBRASKA
PANHANDLE INTO SWRN SOUTH DAKOTA. BASED ON SFC OBS...MUCH OF THIS
PCPN ISN/T REACHING THE GROUND ATTM. AS OF 2 PM CDT...UNDER MOSTLY
CLEAR SKIES...TEMPERATURES RANGED FROM 73 AT VALENTINE...TO 85 AT
IMPERIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM CDT MON MAY 19 2014
THUNDERSTORM CHANCES ARE THE MAIN FORECASTING CONCERN FOR TONIGHT
AND TUESDAY. A TANDEM OF SHORTWAVES WILL LIFT INTO THE HIGH PLAINS
OVER THE NEXT 3 TO 6 HOURS. THE FIRST WILL LIFT FROM EASTERN WYOMING
INTO THE NORTHERN NEBRASKA PANHANDLE...THEN NORTHERN NEBRASKA. THE
SECOND WILL LIFT INTO THE SANDHILLS FROM NERN COLORADO. THE FIRST
DISTURBANCE HAS ALREADY LED TO SOME HIGH BASED SHOWERS OVER THE HIGH
PLAINS OF EASTERN WYOMING. AS THIS ACTIVITY MOVES EAST...IT SHOULD
BECOME BETTER ORGANIZED...LIFTING ACROSS NORTH CENTRAL NEBRASKA
THROUGH THE EVENING HOURS. FURTHER SOUTH...THE SECOND SHORTWAVE WILL
LIFT EAST INTO THE WESTERN SANDHILLS THIS EVENING. CAP STRENGTH WILL
REMAIN IN PLACE THROUGH 00Z WHERE IT BEGINS TO ERODE FROM OGALLALA
TO THEDFORD. IN THESE AREAS...AM EXPECTING CONVECTIVE INITIATION
AROUND THE 6 TO 7 PM CDT TIME FRAME THIS EVENING. BULK SHEAR IS IN
THE 35 TO 45 KT RANGE NEAR THE INITIATION POINT...HOWEVER...IT FALLS
OFF TO AROUND 30 KTS EAST OF HIGHWAY 183...SO AM EXPECTING THE MAIN
SEVERE THREAT TO BE CONFINED TO THE SANDHILLS NORTH OF INTERSTATE 80
AND WEST OF HIGHWAY 183. ISOLATED COVERAGE IS EXPECTED AND IS
SUPPORTED BY THE LATEST 4KM WRF AND HRRR SOLNS WHICH DEVELOP
STRONG...BUT ISOLATED STORMS ACROSS THE SANDHILLS THIS EVENING. AS
FOR SEVERE TYPES...CONTINUED THINKING IS LARGE HAIL FOR THE MAIN
SEVERE TYPE AS LOW LEVEL HELICITIES ARE NOT OVERLY IMPRESSIVE THIS
EVENING. WET BULB ZEROS AROUND 8000 FT AGL FAVOR LARGE HAIL AS WELL.
WE MAY SEE SOME GUSTY WINDS INVOF ANY STORMS...HOWEVER...SINCE
LINEAR SEGMENTS ARE NOT EXPECTED...WIDESPREAD SEVERE WINDS ARE NOT
ANTICIPATED ATTM. CONVECTIVE ACTIVITY IS EXPECTED TO MOVE EAST OF
THE FORECAST AREA BY LATE EVENING...HOWEVER...SOME LIGHT RAIN
SHOWERS WILL CONTINUE TO BE A THREAT IN THE NORTHWESTERN CWA WHERE
MID LEVEL PERSISTS INTO THE OVERNIGHT. FOR TOMORROW...TEMPERATURES
WILL COOL SLIGHTLY AS A FRONTAL BOUNDARY IS FORCED SOUTH INTO
KANSAS. THE MAIN THREAT FOR PCPN WILL FOLLOW. WITH THE EXCEPTION OF
THE WESTERN FORECAST AREA...MAINLY DRY CONDS WILL REMAIN IN PLACE.
HIGHS TUESDAY WILL RANGE FROM AROUND 70 IN THE NORTHWEST...TO NEAR
80 IN THE SOUTHEAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM CDT MON MAY 19 2014
FOR TUESDAY NIGHT...THE 12Z NAM12 AND GFS40 ARE SIMILAR WITH THE
LOCATION OF THE QUASI-STATIONARY FRONT ACROSS NORTHEAST TO SOUTHWEST
KANSAS WITH THE 0-2KM THETA-E RIDGE ALONG THE KANSAS-NEBRASKA
BORDER. THE GREATEST INSTABILITY IS FROM SOUTHEAST NEBRASKA TO NORTH
CENTRAL KANSAS. THERE IS SOME MARGINAL INSTABILITY EXTENDING INTO
THE WESTERN NEBRASKA SANDHILLS AND THE PANHANDLE AND THUNDERSTORMS
ARE POSSIBLE TUESDAY EVENING. THE CONVECTIVE POTENTIAL ENERGY IS
LESS THAN 1000J/KG...SO SEVERE THUNDERSTORMS ARE UNLIKELY.
BY WEDNESDAY AFTERNOON...A FINGER OF THE THETA-E RIDGE EXTENDS
NORTHWESTWARD INTO THE SOUTHERN NEBRASKA PANHANDLE ALONG AN INVERTED
SURFACE TROUGH. WITH SURFACE-BASED CONVECTIVE POTENTIAL ENERGY
(CAPE) OF 2000J/KG WEDNESDAY EVENING AND 0-6KM BULK SHEAR OF
40-50KT...SOME STRONG THUNDERSTORMS SHOULD DEVELOP IN SOUTHWEST
NEBRASKA...POSSIBLY COMING ACROSS INTO THE WESTERN SANDHILLS. LATE
WEDNESDAY NIGHT...THE SURFACE BASED LIFTED INDICES SPREAD INTO
CENTRAL AND NORTH CENTRAL NEBRASKA...SO THERE IS A CHANCE OF
THUNDERSTORMS THERE AFTER 06Z
A SIMILAR SITUATION EXISTS FOR THURSDAY AFTERNOON AND FRIDAY
AFTERNOON. WITH THE FORECAST LOCATIONS OF THE MAXIMUM CAPE NEAR THE
NEBRASKA-KANSAS AND THE NEBRASKA-COLORADO BORDERS...THE HIGHEST
PROBABILITY OF STRONG THUNDERSTORMS WILL BE SOUTH OF INTERSTATE
HIGHWAY 80.
FOR SATURDAY AND SUNDAY...THE FRONT STARTS WASHING OUT. STILL WARM
ADVECTION OVER THE HIGH PLAINS BOUNDARY WILL BRING CONTINUE TO BRING
THE POSSIBILITY OF THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. THE
CAPES WILL NOT BE AS HIGH...THOUGH THE HIGHER CAPES WILL COVER A
LARGER PART OF CENTRAL AND WESTERN NEBRASKA. THE 0-6KM BULK SHEAR IS
VERY WEAK...ONLY ABOUT 20KT OR LOWER...SO HEAVY RAIN WOULD BE THE
PRIMARY THREAT. BY SUNDAY...THE MOST FAVORABLE INSTABILITY WILL
SHIFT INTO EASTERN NEBRASKA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 657 PM CDT MON MAY 19 2014
ISOLATED TSTMS WILL TRACK EAST INTO WESTERN NEBRASKA THIS EVENING.
COVERAGE WILL AGAIN BE ISOLATED AND WILL NOT INCLUDE IN THE TAF
FOR EITHER KVTN OR KLBF. WINDS WILL BE NORTH TO NORTHEAST THROUGH
THE NIGHT AROUND 10 TO 15 KTS. MOSTLY VFR CONDITIONS...EXCEPT NEAR
ANY STORM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...SPRINGER
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
122 AM EDT SUN MAY 18 2014
.SYNOPSIS...A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK THROUGH
THE REGION TODAY. MODIFIED CONTINENTAL POLAR HIGH PRESSURE WILL
OTHERWISE REMAIN OVER THE AREA THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 955 PM SATURDAY...
TONIGHT: A DEEP MID TO UPPER LEVEL TROUGH CONTINUES TO LINGER ACROSS
THE EASTERN U.S.... VERY SLOWLY PUSHING EASTWARD. DISTURBANCES IN
THE CYCLONIC FLOW ALOFT CONTINUE TO MOVE THROUGH THE REGION. ONCE
SUCH DISTURBANCE IS CURRENTLY MOVING THROUGH/LIFTING OFF TO THE
NORTHEAST OF THE AREA. HOWEVER... THE NEXT DISTURBANCE IS FAST
APPROACHING. THIS COMBINED WITH WEAK WAA AT AROUND 850 MB IS HELPING
TO PRODUCE A PATCH OF MOSTLY CLOUDY TO OVERCAST SKIES ACROSS THE
NORTHERN PIEDMONT... AND PORTIONS OF THE REST OF THE AREA. THE
LATEST HRRR EVEN TRIES TO GENERATE SOME VERY LIGHT PRECIP FALLING
FROM THE 6 TO 10 KFT CIGS LATER THIS EVENING INTO THE VERY EARLY
HOURS OF SUNDAY MORNING ACROSS THE FAR NORTHERN PIEDMONT. THUS...
WILL MAINTAIN THE MENTION OF SPRINKLES IN THE FORECAST DURING THIS
TIME FRAME. THIS CLOUD COVER IS EXPECTED TO SLOWLY SHIFT EASTWARD AS
THE 850 MB 00Z ANALYSIS SHOWED THE 850 MB RIDGE EXTENDED INTO THE
COASTAL PLAIN OF CENTRAL NC (WHICH IS FORECAST TO SLOWLY SHIFT
EASTWARD). ADDITIONAL MID LEVEL MOISTURE IS EXPECTED TO SPREAD INTO
THE REGION OVERNIGHT IN ADVANCE OF THE NEXT S/W AS WELL. THUS..
THINK WE WILL SEE PERIOD OF PARTLY TO MOSTLY CLOUDY... EVEN
OVERCAST... OVERNIGHT. THUS... WILL RAISE LOW TEMPS A COUPLE OF
DEGREES FROM THE PREVIOUS FORECAST. THIS YIELDS LOW TEMPS RANGING
FROM THE UPPER 40S TO LOWER 50S... WITH SOME LOW TEMPS OCCURRING
LATE THIS EVENING ACROSS EASTERN AREAS OF THE CWA. -BSD
SUN AND SUN NIGHT: THE TRAILING DISTURBANCE INITIALLY OVER WESTERN
SD WILL PIVOT EAST ACROSS THE SOUTHERN APPALACHIANS ON SUN.
ASSOCIATED RIGHT ENTRANCE UPPER JET FORCING WILL INTERACT WITH A
WEAK FRONTAL ZONE DEVELOPING EASTWARD FROM THE NORTHERN GULF COAST
STATES...AND RESULT IN THE EASTWARD DEVELOPMENT OF A BAND OF LIGHT
RAIN ACROSS SOUTHERN NC FROM LATE MORNING OVER THE SOUTHERN PIEDMONT
TO EARLY-MID AFTERNOON OVER THE SOUTHERN-CENTRAL COASTAL PLAIN. NWP
GUIDANCE IS IN REMARKABLY POOR AGREEMENT FOR A 18-24 HR
FORECAST...WITH THE AMERICAN MODELS STILL THE WETTER AND FARTHER
NORTH SOLUTIONS (0.25-0.50") ACROSS SOUTHERN NC...VERSUS THE NON-
AMERICAN MODEL CONSENSUS OF JUST A FEW HUNDREDTHS OF AN INCH
EXTENDING NORTH INTO THE FAY-CTZ-GSB VICINITIES. CANNOT FIND ANY
NOTABLE DIFFERENCES IN THE MASS OR MOISTURE FIELDS BETWEEN THE
DIFFERING PARENT MODEL QPF SOLUTIONS...SO WILL RETAIN THE GENERAL
"BLEND" SOLUTION OF RECENT DAYS. IF THE CLOUDS AND RAIN INDEED
MATERIALIZE...TEMPERATURES UNIFORMLY IN THE 65-68 DEGREE RANGE WILL
BE LIKELY.
CLEARING WILL OCCUR DURING THE EVENING IN SUBSIDENT CONDITIONS
BEHIND THE DEPARTING SHORTWAVE TROUGH. ANOTHER COOL NIGHT WILL
RESULT...WITH LOWS AGAIN IN THE MIDDLE 40S TO LOWER 50S. -MWS
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 250 PM SATURDAY...
THE WORK WEEK STARTS OFF ON A SUNNY AND DRY...BUT PLEASANTLY MILD
NOTE AS HIGH PRESSURE BUILDS IN FROM THE OHIO VALLEY. MONDAYS HIGHS
WILL BE IN THE LOW TO MID 70S. THE HIGH PRESSURE WILL BE EDGING
SOUTH OF THE AREA TUESDAY WITH SUBSEQUENT RETURN FLOW LEADING TO
INCREASING TEMPERATURES AND MOISTURE. SKIES WILL BE SUNNY
TUESDAY...WITH HIGHS IN THE MID T0 UPPER 70S AFTER A MORNING LOW IN
THE UPPER 40S. MODIFIED AIRMASS AND WESTERLY FLOW WILL MAINTAIN
MILDER MINS IN THE MID TO UPPER 50S TUE NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
HEIGHTS WILL RISE AND MID LEVEL FLOW WILL TRANSITION TO NORTHWEST AS
MID LEVEL RIDGING AMPLIFIES IN THE MIDWEST. THIS WILL RESULT IN A
WARMING TREND WITH WELL ABOVE NORMAL TEMPERATURES FROM WEDNESDAY
INTO THE WEEKEND. HIGHS WEDNESDAY AND THURSDAY WILL REACH THE MID
AND UPPER 80S. A WEAK AND MOSTLY DRY BACKDOOR FRONT WILL BE
SUPPRESSED SLOWLY SOUTH INTO THE AREA THURSDAY...AND LINGER ACROSS
THE SOUTHERN MID ATLANTIC INTO THE WEEKEND. THIS FRONT WILL INCREASE
OUR CHANCE OF MAINLY DIURNAL CONVECTION THURSDAY THROUGH SATURDAY...
MORE SO FRIDAY AND SATURDAY WHEN THE FRONT IS MOST LIKELY TO BE
SOUTH OF THE AREA AND AIDED BY SLOW RETROGRESSION OF THE RIDGING
WHICH WILL ALLOW THE UPPER JET TO EDGE SOUTH AND REDIRECT IT
SOUTHEASTWARD ACROSS THE GREAT LAKES...ENHANCING UPPER DIFFLUENCE.
IN ADDITION...INSTABILITY WILL BE IMPRESSIVE DUE TO STEEP MID LEVEL
LAPSE RATES (LATEST GFS PROGS >7C/KM)...IN THE VICINITY OF THE
STALLED FRONT...AND WILL HAVE SLIGHTLY HIGHER TRENDED POPS IN THE
SOUTHWEST. MIN TEMPERATURES WILL BE MILD THROUGH THE PERIOD...MAINLY
60 TO 65 DEGREES.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL CAUSE PERIODS OF MID
LEVEL CLOUDINESS AND WILL BRING A GOOD CHANCE OF RAIN SHOWERS ACROSS
MOSTLY SOUTHERN PORTIONS OF THE FORECAST AREA...IN VICINITY OF THE
KFAY TERMINAL. CANNOT RULE OUT A BRIEF/SHORT-LIVED PERIOD OF MVFR
CEILINGS AT KFAY IN ASSOCIATION WITH A HEAVIER SHOWER.
OTHERWISE...EXPECT PREDOMINATELY VFR CONDITIONS.
THIS DISTURBANCE WILL EXIT OUR REGION LATE THIS EVENING WITH
CLEARING SKIES IN ITS WAKE. HIGH PRESSURE WILL BUILD AND SETTLE OVER
THE AREA MONDAY INTO TUESDAY...CONTINUING OUR STRETCH OF VFR
CONDITIONS.
FOR WEDNESDAY INTO THE THURSDAY...TEH THREAT FOR ISOLATED-SCATTERED
CONVECTION AND ASSOCIATED SUB-VFR CONDITIONS WILL BEGIN TO INCREASE
AS THE AIR MASS BECOMES MORE MOIST AND INCREASINGLY UNSTABLE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BSD/MWS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...CBL/WSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
957 PM CDT MON MAY 19 2014
.UPDATE...
ISSUED AT 957 PM CDT MON MAY 19 2014
THERE HAVE BEEN A COUPLE ISOLATED STORMS...BUT THEY HAVE REMAINED
WEAK. ANTICIPATE ISOLD ACTIVITY WILL CONTINUE TO BE POSSIBLE ALONG
AND AHEAD OF THE SFC TROUGH. THE ONLY UPDATE WILL BE TO ADD
DRIZZLE TO AREAS EAST OF THE VALLEY. THIS AREA UNDER THE INFLUENCE
OF STRONGER 850MB WARM AIR ADVECTION WHICH IS LIKELY LEADING TO
THE DRIZZLE. THIS FORCING WILL MOVE EAST AFTER 06Z...BUT WITH THE
SFC TROUGH COMING OVERHEAD WILL LINGER THE DRIZZLE MENTION THROUGH
THE NIGHT (IT MAY TURN INTO MORE OF A FOG/VSBY RESTRICTION AFTER
MIDNIGHT...BUT THIS WILL BE A GOOD START).
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 225 PM CDT MON MAY 19 2014
FORECAST CHALLENGE CONCERNS MAINLY NEAR TERM RAIN/TSRA CHANCES AND
TEMPERATURES. MODELS IN REASONABLE AGREEMENT. FOLLOWED SHORT TERM
MESOSCALE MODELS WITH EVENING CONVECTION POTENTIAL AND MODEL BLEND
THERE AFTER.
RELATIVELY SLOW MOVING SURFACE BOUNDARY ORIENTED FROM N CENTRAL ND
INTO NE SD. BEST SURFACE MOISTURE CONVERGENCE SHIFTING INTO THE
VALLEY REGION AHEAD OF BOUNDARY. SOLAR ACROSS SE ND INTO NE SD
VCNTY SURFACE LOW ALONG BOUNDARY HAS ALLOWED FOR DESTABILIZATION
WITH SUFFICIENT CAPE AND INSTABILITY FOR CONVECTION. THIS AREA
CONTINUES TO LOOK LIKE THE FAVORED AREA FOR FURTHER DEVELOPMENT
INTO THE EVENING. MAIN QUESTION WILL BE IF THERE IS ENOUGH UPPER
SUPPORT TO AID IN DEEP CONVECTION. MAIN UPPER JET AXIS NOSING INTO CENTRAL
HIGH PLAINS WITH WEAKER IMPULSE OVER NORTHERN ND. WATER VAPOR ALSO
INDICATING ANOTHER WEAK IMPULSE OVER WYO LIFTING NE. NONE OF THESE
UPPER LEVEL FEATURES SEEM TO FOCUS OVER OUR AREA SO STORM
DEVELOPMENT SOMEWHAT UNCERTAIN. WILL MAINTAIN SOME HIGH CHC POPS
FROM VALLEY EAST AHEAD OF BOUNDARY IN LINE WITH SHORT TERM
MESOSCALE MODEL SOLUTIONS. ANY CONVECTION SHOULD THEN PROPAGATE E-NE
THROUGH THE EVENING AS SURFACE LOW LIFTS TOWARDS THE INTERNATIONAL
BORDER. GFS QUICKEST IN BRINGING BETTER PUSH OF COLD ADVECTION
INTO THE NW FA LATER TONIGHT WITH NAM AND ECMWF A LITTLE SLOWER.
NW MAY ALSO SEE CLOUDS LONGER WHICH MAY ALSO HOLD TEMPERATURES UP.
SURFACE/UPPER LOW WILL DRIFT EAST ALONG MN INTERNATIONAL BORDER
AREA TUESDAY. MAIN CHALLENGE WILL BE HOW FAR SOUTH ANY WRAP AROUND
SHRA GETS INTO THE FA. NOT OVERLY CONFIDENT ON THUNDER POTENTIAL
BUT MAINTAINED CONTINUITY WITH NEIGHBORS. MODELS GENERALLY HAVE
BACKED OFF ON SOUTHWARD EXTENT SO DID TRIM POPS HOLDING BEST
CHANCE ALONG AND NORTH OF HIGHWAY 2. TEMPERATURES WILL HINGE ON
DEGREE OF CLOUD COVER HOWEVER WITH SURFACE WESTERLY FLOW AND COLD
ADVECTION MAINLY MID/LATE AFTERNOON SOUTHERN AREAS SHOULD BE
FAIRLY MILD WITH COOLEST TEMPERATURES ACROSS THE NORTH IN THICKER
CLOUDS/COLDER COLUMN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 225 PM CDT MON MAY 19 2014
SURFACE HIGH PRESSURE WILL BUILD INTO THE FA ON WEDNESDAY.
CONVECTIVE TEMPERATURES INITIALLY LOW HOWEVER COLD POOL SHIFTS
EAST DURING THE DAY SO SHOULD SEE SOME SOLAR ALLOWING TEMPERATURES
TO RECOVER CLOSE TO AVERAGE.
HIGH PRESSURE SHIFTS SLOWLY EAST THURSDAY. RETURN FLOW/WARM
ADVECTION SETS UP FROM VALLEY WEST FOR THE WARMEST READINGS WITH
SLIGHTLY COOLER TEMPERATURES OVER THE EAST WITH LESS MIXING.
WILL START THE THURSDAY NIGHT THROUGH MONDAY PERIOD WITH A BUILDING
RIDGE OVER THE NATIONS MIDSECTION AND A CUTOFF LOW ACROSS THE DESERT
SOUTHWEST. FOR THU NIGHT TO FRIDAY NIGHT SFC HIGH PRESSURE SHOULD
REMAIN OVER THE FA KEEPING IT DRY WITH HIGHS A LITTLE ABOVE NORMAL.
THEREAFTER LOOKING AT THE WESTERN TROUGH SLIDING EAST AND PUTTING
THE FA BACK INTO THE ZONE FOR ADDITIONAL SHOWERS AND TSTMS. IN
ADDITION LOOKS LIKE A POTENTIAL FOR A PERIOD OF ABOVE NORMAL TEMPS
ALTHOUGH 12Z MODELS DIFFER ON HOW WARM. 12Z GFS BRINGS IN MUCH
WARMER AIR AT 850MB AS COMPARED TO THE LATEST ECMWF. CURRENT
GUIDANCE SHOWS HIGHS IN THE MID TO UPPER 70S AND WILL STICK WITH
THAT FOR NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 652 PM CDT MON MAY 19 2014
THE GENERAL TREND WILL BE IMPROVING CONDITIONS FROM WEST TO EAST
TONIGHT. LAV AND RAP GUIDANCE HAS A GOOD HANDLE ON CURRENT
CONDITIONS AND WILL USE FOR TIMING PURPOSES. MVFR CONDITIONS WILL
BECOME VFR EARLY THIS EVENING FOR THE VALLEY SITES...AND MORE
TOWARD SUNRISE FOR SITES EAST OF THE VALLEY. THE POTENTIAL EXISTS
FOR MVFR CIGS TO AGAIN INVADE THE REGION TUESDAY AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...VOELKER
LONG TERM...GODON/VOELKER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
820 PM CDT MON MAY 19 2014
.UPDATE...
ISSUED AT 820 PM CDT MON MAY 19 2014
AREAS OF LIGHT SHOWERS AND ISOLATED THUNDERSHOWERS CONTINUE THIS
EVENING ACROSS WESTERN AND PORTIONS OF WEST CENTRAL NORTH DAKOTA.
WATER VAPOR IMAGERY CLEARLY SHOWS AN UPPER LOW SPINNING OVER FAR
SOUTHEAST ALBERTA...CONTINUING TO GENERATE AND PINWHEEL AREAS OF
SHOWERS AND ISOLATED THUNDERSHOWERS INTO NORTHEAST MONTANA. AT THE
SURFACE A SECONDARY COLD FRONT WAS LOCATED FROM THE TURTLE
MOUNTAINS BACK INTO GARRISON AND WEST TO SIDNEY. THE SHOWERS AND
THUNDERSTORMS HAVE BEEN MOST CONCENTRATED ALONG THIS LOW LEVEL
CONVERGENCE REGION...AND WILL CONTINUE TO RIDE AND HOVER AROUND
THIS BOUNDARY THROUGH THE EVENING HOURS PER LATEST HRRR. THE HRRR
MAINTAINS A STEADY STATE FLOW WITH THESE SHOWERS THROUGH 09Z
TUESDAY. LATEST SPC MESOSCALE ANALYSIS SUPPORTS MOST UNSTABLE CAPE
VALUES OF AROUND 500 J/KG WITH WEAK SHEAR IN THE WEST. THE BEST
CAPE AND SHEAR STILL RESIDES IN THE JAMES RIVER VALLEY AND WILL
MONITOR THINGS CLOSELY AS THE UPSTREAM PRECIPITATION EDGES CLOSER
INTO THIS AREA.
UPDATE ISSUED AT 530 PM CDT MON MAY 19 2014
LATEST LOCAL/REGIONAL RADAR CONTINUES TO SHOW SCATTERED
THUNDERSTORMS IN NORTHWEST NORTH DAKOTA. RECENT SPOTTER REPORTS
HAVE BEEN CONSISTENT WITH PEA SIZED HAIL AND HEAVY DOWNPOURS WITH
CELLS MOVING ACROSS MCKENZIE COUNTY AND INTO THEODORE ROOSEVELT
PARK NORTH. OUR CURRENT SPECIAL WEATHER STATEMENT HANDLES THIS
AREA WELL AND WILL CONTINUE. CONCERN FOR THE NEXT COUPLE OF HOURS
IS THE SECONDARY AREA OF THUNDERSTORMS JUST READY TO APPROACH
SCOBEY MONTANA. REPORTS OF NICKEL SIZED HAIL WEST OF SCOBEY. THE
LATEST HRRR MAINTAINS REFLECTIVITY INTENSITY AS THIS AREA CROSSES
OUR NORTHWEST BORDER BETWEEN 00Z AND 03Z. IN ADDITION...ISOLATED
THUNDERSTORMS APPROACHING BAKER MONTANA WILL ALSO BE WATCHED THIS
EVENING AS THEY MOVE INTO THE SOUTHWEST. BOWMAN RADAR INDICATIVE
OF ISOLATED SHOWERS WITH POSSIBLE THUNDERSTORM DEVELOPMENT
SHORTLY. LASTLY...WILL WATCH FOR THE SOUTHERN JAMES RIVER VALLEY
FOR THUNDERSTORM DEVELOPMENT. SOME INDICATION PER RAP AND NAM THAT
WE COULD SEE SOMETHING THIS EVENING. ALL ACTIVITY IS FORECAST TO
GRADUALLY WEAKEN AND WANE BY 06Z TUESDAY. MAIN UPDATE WAS TO KEEP
SCATTERED THUNDERSTORMS GOING INTO THE MID EVENING HOURS NORTHWEST
AND KEEP SOME MENTION OF THUNDERSTORMS IN THE SOUTHWEST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 300 PM CDT MON MAY 19 2014
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD IS CONVECTIVE
TRENDS/COVERAGE/INTENSITY THROUGH THIS EVENING.
THE LATEST RUNS OF THE HRRR/WRF/RAP ALL INDICATING SHOWERS AND
STORMS TO DEVELOP OR ADVECT INTO PARTS OF THE FORECAST AREA THIS
AFTERNOON. ONE PRIMARY AREA WILL LIKELY BE THE NORTHWEST...WITH
CURRENT STORMS ONGOING IN NORTHEAST MONTANA...ADDED BY AN UPPER
LOW IN THE VICINITY. THE PRIMARY THREAT AREA FOR STRONG TO NEAR SEVERE
STORMS STILL APPEARS TO BE IN THE JAMES RIVER VALLEY AND...WHERE
THE MOST FAVORABLE DEEP LAYER SHEAR...MOISTURE...AND MID-LEVEL
LAPSE RATES ARE LOCATED. THIS AREA REMAINS OUTLOOKED IN THE 5
PERCENT RISK AREA FOR HAIL. WILL MAINTAIN CHANCE POPS IN THE NORTH
AND THROUGH THE JAMES RIVER VALLEY...WITH SLIGHT CHANCE POPS DOWN
TO NEAR TO INTERSTATE 94 CORRIDOR.
SHOWERS AND ISOLATED THUNDERSTORMS WILL DIMINISH THIS EVENING. A SECONDARY
COLD FRONT WILL DROP SOUTH INTO THE STATE OVERNIGHT...ACCOMPANIED BY
STRATUS. HOWEVER...ADDITIONAL RAIN WILL LIKELY STAY NORTH OF THE BORDER.
ON TUESDAY...EXPECT SOMEWHAT COOLER TEMPERATURES WITH A FEW SHOWERS
POSSIBLE ACROSS THE FAR NORTH DURING THE AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CDT MON MAY 19 2014
TUESDAY NIGHT AND WEDNESDAY...SURFACE HIGH PRESSURE MOVES INTO THE
STATE ALONG WITH THE EXITING OF AN UPPER LEVEL SHORTWAVE. COOL AND
DRY WITH TUESDAY NIGHT LOWS FROM THE UPPER 30S TO LOWER 40S. MOSTLY
SUNNY ON WEDNESDAY WITH HIGHS IN THE 60S.
WEDNESDAY NIGHT AND THURSDAY...THE SURFACE HIGH IS CENTERED EAST OF
THE FORECAST AREA WITH SOUTHERLY SURFACE FLOW AND INCREASING
DEWPOINTS. THE MODELS ARE IN AGREEMENT WITH SOME SHORTWAVE ENERGY
MOVING NORTH/NORTHEASTWARD FROM A LONGWAVE TROUGH OVER THE ROCKIES.
CHANCES OF THUNDERSTORMS IN SOUTHWESTERN NORTH DAKOTA WEDNESDAY
NIGHT AND OVER THE WESTERN HALF OF THE STATE ON THURSDAY. A BIT
WARMER THURSDAY WITH HIGHS 70-75.
THURSDAY NIGHT THROUGH MONDAY THE MODELS ARE IN FAIR AGREEMENT OVER
THE WESTERN AND CENTRAL US WITH AN UPPER LEVEL LOW CUTTING OFF FROM
THE LONGWAVE TROUGH AND REMAINING OVER THE 4-CORNERS AREA THROUGH
SUNDAY. THE MODELS BEGIN TO DIVERGE ON MONDAY WITH THE EUROPEAN
MODEL LIFTING THE CUTOFF LOW NORTHEASTWARD INTO THE CENTRAL
PLAINS...AND THE GFS MOVING THE CUTOFF LOW EASTWARD INTO THE
SOUTHERN PLAINS. THUS HAVE SMALL CHANCES OF THUNDERSTORMS THURSDAY
NIGHT THROUGH FRIDAY NIGHT...WITH INCREASING CHANCES SATURDAY.
CHANCES OF SHOWERS AND THUNDERSTORMS A BIT LOWER SUNDAY THROUGH
MONDAY WITH MORE UNCERTAINTY.
THE GOOD NEWS IS THAT TEMPERATURES SHOULD BE SEASONABLE TO SLIGHTLY
ABOVE AVERAGE WITH HIGHS IN THE 75-80 DEGREE RANGE FOR THE MEMORIAL
DAY WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 530 PM CDT MON MAY 19 2014
MVFR TO IFR/VLIFR CIGS HOVERING OVER FAR NORTHERN NORTH DAKOTA AND
INTO SOUTHERN SASKATCHEWAN AND MANITOBA MONDAY EVENING...WILL SLOWLY
MIGRATE SOUTH MONDAY NIGHT. EXPECT CIGS TO DETERIORATE TO VLIFR AT
KISN BY TUESDAY 08Z...WITH MVFR CIGS AT KMOT BY 09Z. MVFR CIGS WILL
SLIDE SOUTH TO KDIK BY 15Z TUESDAY...WITH CIGS REMAINING JUST ABOVE
VFR AT KBIS/KJMS DURING THE DAY TUESDAY. THE VLIFR CIGS AT KISN WILL
LIFT TO MVFR TUESDAY MORNING AND TO LOW VFR BY 21Z TUESDAY. KMOT
WILL REMAIN AT MVFR STATUS THROUGH THE DAY TUESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
LONG TERM...JV
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
652 PM CDT MON MAY 19 2014
.UPDATE...
ISSUED AT 652 PM CDT MON MAY 19 2014
NOT MUCH HAS CHANGED SINCE THE LAST UPDATE...EXCEPT THAT
INSTABILITY HAS SLIGHTLY DECREASED ACROSS SOUTHEAST NORTH DAKOTA.
FORCING REMAINS RELATIVELY WEAK...AND THIS WEAK FORCING LIKELY HAS
BEEN UNABLE TO OVERCOME THE WEAK CAPPING STILL IN PLACE. ANTICIPATE
ISOLATED ACTIVITY AS THE SFC TROUGH PROPAGATES THROUGH THE REGION
THIS EVENING...BUT THE COVERAGE WILL NOT BE MORE THAN ISOLD (AND
LOWERED POPS ACCORDINGLY).
GIVEN THE HIGHER DEW POINT VALUES IN PLACE...FOG MAY BE POSSIBLE
WITHIN THE SFC TROUGH AFTER MIDNIGHT. THE LAST FEW RUNS OF THE
HRRR HAVE INDICATED FOG POSSIBLE ACROSS WEST CENTRAL MINNESOTA
TONIGHT. WILL EVALUATE THIS POTENTIAL FURTHER WITH THE NEXT
UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 225 PM CDT MON MAY 19 2014
FORECAST CHALLENGE CONCERNS MAINLY NEAR TERM RAIN/TSRA CHANCES AND
TEMPERATURES. MODELS IN REASONABLE AGREEMENT. FOLLOWED SHORT TERM
MESOSCALE MODELS WITH EVENING CONVECTION POTENTIAL AND MODEL BLEND
THERE AFTER.
RELATIVELY SLOW MOVING SURFACE BOUNDARY ORIENTED FROM N CENTRAL ND
INTO NE SD. BEST SURFACE MOISTURE CONVERGENCE SHIFTING INTO THE
VALLEY REGION AHEAD OF BOUNDARY. SOLAR ACROSS SE ND INTO NE SD
VCNTY SURFACE LOW ALONG BOUNDARY HAS ALLOWED FOR DESTABILIZATION
WITH SUFFICIENT CAPE AND INSTABILITY FOR CONVECTION. THIS AREA
CONTINUES TO LOOK LIKE THE FAVORED AREA FOR FURTHER DEVELOPMENT
INTO THE EVENING. MAIN QUESTION WILL BE IF THERE IS ENOUGH UPPER
SUPPORT TO AID IN DEEP CONVECTION. MAIN UPPER JET AXIS NOSING INTO CENTRAL
HIGH PLAINS WITH WEAKER IMPULSE OVER NORTHERN ND. WATER VAPOR ALSO
INDICATING ANOTHER WEAK IMPULSE OVER WYO LIFTING NE. NONE OF THESE
UPPER LEVEL FEATURES SEEM TO FOCUS OVER OUR AREA SO STORM
DEVELOPMENT SOMEWHAT UNCERTAIN. WILL MAINTAIN SOME HIGH CHC POPS
FROM VALLEY EAST AHEAD OF BOUNDARY IN LINE WITH SHORT TERM
MESOSCALE MODEL SOLUTIONS. ANY CONVECTION SHOULD THEN PROPAGATE E-NE
THROUGH THE EVENING AS SURFACE LOW LIFTS TOWARDS THE INTERNATIONAL
BORDER. GFS QUICKEST IN BRINGING BETTER PUSH OF COLD ADVECTION
INTO THE NW FA LATER TONIGHT WITH NAM AND ECMWF A LITTLE SLOWER.
NW MAY ALSO SEE CLOUDS LONGER WHICH MAY ALSO HOLD TEMPERATURES UP.
SURFACE/UPPER LOW WILL DRIFT EAST ALONG MN INTERNATIONAL BORDER
AREA TUESDAY. MAIN CHALLENGE WILL BE HOW FAR SOUTH ANY WRAP AROUND
SHRA GETS INTO THE FA. NOT OVERLY CONFIDENT ON THUNDER POTENTIAL
BUT MAINTAINED CONTINUITY WITH NEIGHBORS. MODELS GENERALLY HAVE
BACKED OFF ON SOUTHWARD EXTENT SO DID TRIM POPS HOLDING BEST
CHANCE ALONG AND NORTH OF HIGHWAY 2. TEMPERATURES WILL HINGE ON
DEGREE OF CLOUD COVER HOWEVER WITH SURFACE WESTERLY FLOW AND COLD
ADVECTION MAINLY MID/LATE AFTERNOON SOUTHERN AREAS SHOULD BE
FAIRLY MILD WITH COOLEST TEMPERATURES ACROSS THE NORTH IN THICKER
CLOUDS/COLDER COLUMN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 225 PM CDT MON MAY 19 2014
SURFACE HIGH PRESSURE WILL BUILD INTO THE FA ON WEDNESDAY.
CONVECTIVE TEMPERATURES INITIALLY LOW HOWEVER COLD POOL SHIFTS
EAST DURING THE DAY SO SHOULD SEE SOME SOLAR ALLOWING TEMPERATURES
TO RECOVER CLOSE TO AVERAGE.
HIGH PRESSURE SHIFTS SLOWLY EAST THURSDAY. RETURN FLOW/WARM
ADVECTION SETS UP FROM VALLEY WEST FOR THE WARMEST READINGS WITH
SLIGHTLY COOLER TEMPERATURES OVER THE EAST WITH LESS MIXING.
WILL START THE THURSDAY NIGHT THROUGH MONDAY PERIOD WITH A BUILDING
RIDGE OVER THE NATIONS MIDSECTION AND A CUTOFF LOW ACROSS THE DESERT
SOUTHWEST. FOR THU NIGHT TO FRIDAY NIGHT SFC HIGH PRESSURE SHOULD
REMAIN OVER THE FA KEEPING IT DRY WITH HIGHS A LITTLE ABOVE NORMAL.
THEREAFTER LOOKING AT THE WESTERN TROUGH SLIDING EAST AND PUTTING
THE FA BACK INTO THE ZONE FOR ADDITIONAL SHOWERS AND TSTMS. IN
ADDITION LOOKS LIKE A POTENTIAL FOR A PERIOD OF ABOVE NORMAL TEMPS
ALTHOUGH 12Z MODELS DIFFER ON HOW WARM. 12Z GFS BRINGS IN MUCH
WARMER AIR AT 850MB AS COMPARED TO THE LATEST ECMWF. CURRENT
GUIDANCE SHOWS HIGHS IN THE MID TO UPPER 70S AND WILL STICK WITH
THAT FOR NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 652 PM CDT MON MAY 19 2014
THE GENERAL TREND WILL BE IMPROVING CONDITIONS FROM WEST TO EAST
TONIGHT. LAV AND RAP GUIDANCE HAS A GOOD HANDLE ON CURRENT
CONDITIONS AND WILL USE FOR TIMING PURPOSES. MVFR CONDITIONS WILL
BECOME VFR EARLY THIS EVENING FOR THE VALLEY SITES...AND MORE
TOWARD SUNRISE FOR SITES EAST OF THE VALLEY. THE POTENTIAL EXISTS
FOR MVFR CIGS TO AGAIN INVADE THE REGION TUESDAY AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...VOELKER
LONG TERM...GODON/VOELKER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1010 AM CDT SUN MAY 18 2014
.UPDATE...
ISSUED AT 953 AM CDT SUN MAY 18 2014
MORNING UPDATE MAINLY FOR POPS/WEATHER THIS AFTERNOON AND TONIGHT.
CONVECTIVE TIMING/SEVERE POTENTIAL IS THE MAIN FORECAST CONCERN
THROUGH TONIGHT. THE SOUTHWEST HAS BEEN OUTLOOKED IN SLIGHT RISK
FOR POTENTIAL SEVERE WEATHER AS EARLY AS LATE AFTERNOON. THE
LATEST HRRR IS INDICATING POTENTIAL FOR A FEW DISCRETE CELLS
DEVELOPING WEST BEFORE 00Z. MORE WIDESPREAD STORMS WITH MODERATE
TO HEAVY RAIN WILL PUSH ACROSS THE FORECAST AREA TONIGHT AND
LINGER INTO MONDAY MORNING NORTH. ML CAPES AOA 1000 J/KG AND DEEP
LAYER SHEAR UP TO 60 KTS WILL SUPPORT SOME LARGE HAIL...WITH
RELATIVELY DRY SUB-CLOUD LAYER CONTRIBUTING TO STRAIGHT LINE WIND
THREAT. INCREASING LOW LEVEL SHEAR/HELICITY NEAR AND AFTER 00Z
THIS EVENING MIGHT ALSO SUPPORT AN ISOLATED TORNADO.
UPDATE ISSUED AT 650 AM CDT SUN MAY 18 2014
EARLY MORNING RADAR MOSAIC SHOWS A FEW SHOWERS MOVING TOWARDS FAR
SOUTHWEST NORTH DAKOTA FROM EASTERN MONTANA. THE LATEST
OBSERVATION FROM BAKER MONTANA IS REPORTING RAIN...SO HAVE CHANGED
TO COVERAGE WORDING IN THE FORECAST WITH ISOLATED SHOWERS THIS
MORNING. THE LATEST NAM BRINGS A CHANCE OF SHOWERS AND
THUNDERSTORMS TOWARDS THE MONTANA / NORTH DAKOTA BORDER LATE THIS
AFTERNOON...WITH THE BETTER CHANCES ARRIVING TONIGHT. THIS IS IN
LINE WITH THE CURRENT FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT SUN MAY 18 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING LATER TODAY THROUGH TONIGHT
ACROSS THE LOCAL AREA.
CURRENTLY...UPPER LEVEL RIDGE AXIS STRETCHED NORTH TO SOUTH IN THE
LEE OF THE ROCKIES THIS MORNING. DEEP LOW PRESSURE OFF THE PACIFIC
NORTHWEST COAST DRIVING THE RIDGE EASTWARD. S/WV IMPULSE WEST OF
THE RIDGE LIFTING EAST-NORTHEAST ACROSS SOUTHERN MONTANA
MAINTAINING AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS BETWEEN
BILLINGS AND MILES CITY...PUSHING EASTWARD. HIGH RES MODELS TRY TO
BRING THIS ACTIVITY INTO SOUTHWESTERN ND AFTER 12Z. WILL STAY THE
COURSE WITH THIS FORECAST ISSUANCE AND KEEP THE AM HOURS DRY FOR
NOW.
SOME UNCERTAINTY ON HOW THE AFTERNOON/EARLY EVENING WILL PLAY OUT
REGARDING SHOWERS/THUNDERSTORMS. LATEST MODELS SUGGEST MINIMAL
ACTIVITY THROUGH 00Z WITH THE RIDGE AXIS MOVING THROUGH FAR
WESTERN ND 22-23Z AND SURFACE LOW PRESSURE NOT ARRIVING UNTIL 03Z
OR AFTER. ALSO...STRONG MID LEVEL S/WV TRIGGER WILL STILL BE
ACROSS CENTRAL MONTANA AT 00Z AND WILL NOT GENERATE FORCING
ACROSS WESTERN NORTH DAKOTA UNTIL THE EVENING HOURS. DOES APPEAR
WE WILL HAVE ENOUGH OVERRUNNING FLOW TO GENERATE ELEVATED SHOWERS
OR ISOLATED THUNDERSTORMS AHEAD OF THE LOW WEST INTO NORTH CENTRAL
THIS AFTERNOON/EARLY EVENING...BUT TO THE NORTH AND EAST OF THE
MORE FAVORABLE SFC-BASED CAPE AND 0-6KM SHEAR VALUES ACROSS THE
SOUTHWEST. ALSO REGARDING THE SOUTHWEST...LATEST BUFFER SOUNDINGS
SUGGEST A POSSIBLE CAPPING INVERSION DURING PEAK HEATING TIME
21-01Z. SUPPORTING THIS POSSIBLE SCENARIO...THE 4KM WRF/RAP/ECMWF
DEPICT NO STRONG CONVECTION ACROSS THE SOUTHWEST UNTIL WELL AFTER
00Z.
INCREASING CHANCES FOR PRECIPITATION THIS EVENING THROUGH THE
OVERNIGHT PERIOD FOR MOST LOCATIONS AS THE MID LEVEL WAVE AND ITS
ASSOCIATED SURFACE LOW MOVE ACROSS THE REGION. MOST FAVORABLE
AREAS FOR MOISTURE WILL BE ALONG TO NORTH AND EAST OF THE MISSOURI
RIVER AS SOUTHWEST NORTH DAKOTA GETS DRY SLOTTED LATE TONIGHT.
REGARDING T-STORM/SEVERE CHANCES...MOST FAVORABLE AREA FOR STRONG
CONVECTION STILL LOOKS LIKE THE SOUTHWEST WHERE MUCAPE/DEEP LAYER
SHEAR REMAIN ROBUST THROUGH MUCH OF TONIGHT...TRYING TO SPREAD
EAST (HIGHEST WITH THE NAM...NEGLIGIBLE WITH THE ECMWF) INTO
CENTRAL NORTH DAKOTA OVERNIGHT COUPLED WITH A 45-55KT LOW LEVEL
JET. WILL NOT MENTION SEVERE AT THIS TIME IN THE GRIDS...BUT WILL
BEEF UP THE HWO FOR TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN MAY 18 2014
SURFACE LOW PRESSURE WILL CONTINUE TO MAKES IT WAY ACROSS THE
NORTHERN PLAINS MONDAY AND TUESDAY. A DRY SLOT WILL MOVE INTO
PARTS OF WESTERN AND SOUTHERN NORTH DAKOTA MONDAY AS THE LOW LIFTS
ACROSS THE REGION. WILL SHOW A TIGHT POP GRADIENT ACROSS THE
FORECAST AREA MONDAY WITH A DRY FORECAST IN THE FAR SOUTHWEST...TO
CATEGORICAL POPS IN THE NORTH. WEAK INSTABILITY LINGERS MONDAY
MORNING...BUT INCREASES AGAIN IN THE EASTERN HALF OF THE FORECAST
AREA MONDAY AFTERNOON...SO WILL CONTINUE TO CARRY THUNDERSTORMS IN
THE WX TYPE GRID.
THE RAIN CHANCES SHOULD DIMINISH EVEN MORE IN THE SOUTH MONDAY
NIGHT...WITH MAINLY A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
IN THE NORTH...CLOSER TO THE SURFACE LOW. ADDITIONAL SHOWERS AND
ISOLATED THUNDERSTORMS COULD WRAP AROUND THE LOW TUESDAY ACROSS
ROUGHLY THE NORTHERN HALF OF THE FORECAST AREA.
WEDNESDAY INTO THE WEEKEND WILL FEATURE BUILDING HEIGHTS AT H5 WITH
OCCASIONAL WEAK WAVES MOVING THROUGH THE UPPER FLOW. THIS WILL
BRING CHANCES OF SHOWERS / THUNDERSTORMS...BUT DO NOT EXPECT THE
OUTER PERIODS TO BE A WASH-OUT BY ANY MEANS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 640 AM CDT SUN MAY 18 2014
EXPECT VFR CONDITIONS WITH WINDS BECOMING SOUTH THEN SOUTHEAST
SUNDAY MORNING AND INCREASING TO 15-18 KNOTS. LOW PRESSURE
APPROACHES FROM WYOMING SUNDAY AFTERNOON WITH INCREASING CHANCES
FOR SHOWERS/THUNDERSTORMS KISN-KDIK 00Z-02Z MONDAY SPREADING EAST
SUNDAY NIGHT. WILL CARRY SHOWERS FOR NOW...BUT COULD SEE
THUNDERSTORMS BEING ADDED IF CONFIDENCE IN THEM REACHING THE
TERMINALS GROWS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RP KINNEY
SHORT TERM...NH
LONG TERM...CK
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
641 PM EDT SUN MAY 18 2014
.SYNOPSIS...
HIGH PRESSURE SETTLES IN TONIGHT. WARM FRONT TUESDAY. UNSETTLED
MID WEEK WITH A COLD FRONT SAGGING IN LATE WEDNESDAY INTO
THURSDAY. ANOTHER BROAD HIGH PRESSURE NEXT WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
630 PM UPDATE...
BASED ON NEW MODEL GUIDANCE AND OBSERVED OVERNIGHT LOWS LAST
NIGHT...ELECTED TO UPGRADE RANDOLPH/POCAHONTAS TO A FREEZE
WARNING. LATEST MAV GUIDANCE AND LAMP TAKE EKN DOWN INTO THE UPPER
20S WHICH WOULD CORRELATE A BIT LOWER IN COLD SPOTS OF E RANDOLPH
COUNTY...IE GLADY. HIGHER RIDGETOPS MAY NOT GET QUITE AS COLD AS
LAST NIGHT WITH SOME RECOVERY IN H85 TEMPS VS LAST NIGHT BUT STILL
BELIEVE A COUNTY WIDE AVG CAN BE ACHIEVED. NO OTHER CHANGES TO
HEADLINES AT THIS TIME. STILL EXPECT PATCHY FROST IN AREAS NOT IN
FROST ADVISORY...IE TRI STATE REGION.
PREVIOUS DISCUSSION BELOW...
TRANQUIL WX IN THE NEAR-TERM PERIOD CHARACTERIZED BY SFC HIGH
PRESSURE AND AMPLIFYING NW FLOW ALOFT.
TONIGHT...SFC HIGH PRESSURE BUILDS IN FROM THE NORTH AND IS
ESSENTIALLY CENTERED OVER THE NORTH AND NORTHEAST ZONES BY 09Z-12Z
MON WITH MOSTLY CLEAR SKIES AND NEAR-CALM WINDS OVERNIGHT. STILL
SOME UNCERTAINTY REGARDING OVERNIGHT MINS AND ANY SUBSEQUENT FROST
HIGHLIGHTS...MAINLY WITH REGARD TO OVERNIGHT DEWPOINTS. VARIOUS NEAR
AND SHORT TERM NWP WIDE APART ON OVERNIGHT DEWPOINTS...WHICH LIKELY
STEM FROM EXACTLY HOW LOW DEWPTS DROP TODAY WITH MIXING. AT
15Z...HSP CURRENTLY REPORTING A 28F TD. LATEST RUC13 AND HRRR
OUTPUT...AMONG OTHERS...SUGGEST DEWPOINTS WAY DOWN IN THE MID 20S
LOWLANDS THIS AFTERNOON...AND CONTINUING ALL NIGHT.
MEANWHILE...LATEST LAMP GUIDANCE KEEPS DEWPTS IN THE UPPER 30S.
NON-CONVECTIVE NWP RUN THE GAMUT IN BETWEEN...KEEPING DEWPOINTS
GENERALLY LOW/MID 30S...AND SOME A BIT HIGHER THAN THAT. PLAN ON
WATCHING AFTERNOON DEWPOINTS BEFORE MAKING A FINAL CALL ON COVERAGE
OF TONIGHT/S FROST ADVISORY...BUT RIGHT NOW ANTICIPATE PROBABLY
REMAINING CLOSE TO SOME FORM OF CONSMOS WHICH IS MORE CONSISTENT
ACROSS THE BOARD AT THIS POINT WITH TD/S RECOVERING INTO THE
MID 30S FOR THE LOWLANDS...AFTER AFTERNOON TD/S THIS AFTERNOON
MIX DOWN INTO THE LOW 30S. FROST DOES APPEAR MORE LIKELY TONIGHT
VERSUS LAST NIGHT...AND DO ANTICIPATE A FROST ADVISORY NEEDED FOR AT
LEAST SOME OF THE EASTERN MOUNTAINS COUNTIES.
MONDAY...VERY NICE AND PLEASANT DAY IS IN STORE FOR THE AREA UNDER
MOSTLY SUNNY TO PERHAPS SOME PARTLY CLOUDY SKIES...ALONG WITH WARMER
TEMPERATURES AND CONTINUED LIGHT WINDS. LATEST NAM12 IS HINTING AT
THE POSSIBILITY OF SOME LIGHT CONVECTIVE SHOWERS ALONG THE HIGHEST
RIDGES OF POCAHONTAS COUNTY AREA...BUT THE CONVERGENCE APPEARS VERY
WEAK AND WILL TREAT THIS WITH ONLY A SLIGHT RAISE OF SILENT POPS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
MODELS ARE IN AGREEMENT WITH HIGH PRESSURE EXITING THE EASTERN
MOUNTAINS BY MONDAY NIGHT. AT THE SAME TIME...WIND TURNS FROM THE
SOUTHWEST...AHEAD OF THE NEXT FRONTAL SYSTEM...TO BRING AN INCREASE
LOW LEVEL MOISTURE...SOME CLOUDS FROM WEST TO EAST. A MID LEVEL
SHORTWAVE WILL PASS ACROSS OUR NORTH TUESDAY...WHILE A WARM FRONT
LIFTS NORTH NORTHEAST ACROSS THE AREA. THESE FEATURES WILL INTERACT
TO BRING CHANCE FOR PCPN MAINLY ACROSS THE NORTHERN THIRD OF THE
AREA.
ADDITIONAL MID LEVEL SHORTWAVES ARE SUGGESTED BY MODELS TO MOVE EAST
UNDER ALMOST ZONAL FLOW BY MID WEEK. WITH THE INCREASE IN LOW LEVEL
MOISTURE...SOME FORCING FROM THE SHORTWAVES AND BEING IN THE WARM
SECTOR...KEPT HIGH CHANCE POPS MAINLY ACROSS THE NORTHERN SECTIONS
WEDNESDAY. IF FACT...IT COULD BE QUITE UNSTABLE ON WEDNESDAY WITH
SFC BASED CAPE EXCEEDING 1500 J/KG...DEEP LAYERED SHEAR UP TO 40
KNOTS MAINLY NORTH...AND PRECIPITABLE WATER AROUND 1.5 INCHES.
THE COLD FRONT WILL REACH SOUTHEAST OH...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS BY LATE WEDNESDAY NIGHT INTO EARLY THURSDAY...THEN
SPREAD NORTHWEST TO SOUTHEAST LATER THURSDAY WITH GOOD CHANCE FOR
SHOWERS AND THUNDERSTORMS. KEPT LIKELY POPS AS SUGGESTED BY THE SREF
WITH SUPPORT FROM THE GFS AND ECMWF.
THE SOUTHWEST FLOW AND ASSOCIATED WARMER AIRMASS WILL BRING A
WARMING TREND THROUGH THE PERIOD. TEMPERATURES EXPECTED TO REACH
NEAR 80 DEGREES TUESDAY...ESPECIALLY SOUTH AND WEST WITH MORE
SUNSHINE. EVEN WARMER A AFTERNOON CAN BE EXPECTED WEDNESDAY AHEAD OF
THE COLD FRONT UNDER WARM ADVECTION.
USED A BLEND OF HPC GUIDANCE AND ALL BLEND MOS GUIDANCE THROUGH THE
PERIODS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
BY THURSDAY THE COLD FRONT WILL BE EXITING THE EASTERN
MOUNTAINS...ALLOWING DRY AND FRESHER AIR TO SET IN FROM THE WEST. A
SFC HIGH PRESSURE DEVELOPS ACROSS THE GREAT LAKES...OH VALLEY INTO
WV THROUGH THE WEEKEND WITH NEAR CALM FLOW.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
SCT FLAT CUMULUS FIELD DEVELOPING THIS AFTERNOON IN HEATING/MIXING
WITH BASES IN THE 4-5KFT RANGE. LIGHT NORTH/NORTHEAST WINDS
CONTINUE TODAY.
EXPECT SOME LATE VALLEY FOG TO DEVELOP AGAIN UNDER GOOD RADIATIONAL
COOLING TONIGHT...PARTICULARLY OVER THE RIVERS...AS WINDS GO NEAR-
CALM. ALSO EXPECTING FROST TO OCCUR AS WELL...PARTICULARLY FOR
LOCATIONS NORTH AND EAST...WHICH MAY LIMIT FOG EXPANSION SOME. ALL
IN ALL...KEPT ALL LOCATIONS VFR THROUGHOUT THE OVERNIGHT HOURS
EXCEPT EKN...WHERE MVFR/IFR VIS LIKELY AFTER 06Z MON.
AS SFC HIGH PRESSURE CONTINUES OFF TO THE EAST...WIND DIRECTIONS
GRADUALLY CONTINUE TO VEER TO THE EAST. WIND SPEEDS HOWEVER WILL
REMAIN ON THE LIGHT SIDE. ANY REDUCTIONS IN VISIBILITY DURING THE
OVERNIGHT AND EARLY MORNING HOURS WILL RAPIDLY SCATTER BY 12Z-13Z
AS TEMPS QUICKLY WARM THROUGH THE MORNING HOURS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: HIGH...ASIDE FROM FOG POTENTIAL.
ALTERNATE SCENARIOS: FOG TIMING AND COVERAGE TONIGHT MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 00Z TUESDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED AT THIS TIME.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FROST ADVISORY FROM 2 AM TO 9 AM EDT MONDAY FOR WVZ006>011-
013>020-024>040.
FREEZE WARNING FROM 2 AM TO 9 AM EDT MONDAY FOR WVZ046-047.
OH...FROST ADVISORY FROM 2 AM TO 9 AM EDT MONDAY FOR OHZ066-067-075-
076-085-086.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/50
NEAR TERM...50/30
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...50
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
252 PM EDT SUN MAY 18 2014
.SYNOPSIS...
HIGH PRESSURE SETTLES IN TONIGHT. WARM FRONT TUESDAY. UNSETTLED
MID WEEK WITH A COLD FRONT SAGGING IN LATE WEDNESDAY INTO
THURSDAY. ANOTHER BROAD HIGH PRESSURE NEXT WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
TRANQUIL WX IN THE NEAR-TERM PERIOD CHARACTERIZED BY SFC HIGH
PRESSURE AND AMPLIFYING NW FLOW ALOFT.
TONIGHT...SFC HIGH PRESSURE BUILDS IN FROM THE NORTH AND IS
ESSENTIALLY CENTERED OVER THE NORTH AND NORTHEAST ZONES BY 09Z-12Z
MON WITH MOSTLY CLEAR SKIES AND NEAR-CALM WINDS OVERNIGHT. STILL
SOME UNCERTAINTY REGARDING OVERNIGHT MINS AND ANY SUBSEQUENT FROST
HIGHLIGHTS...MAINLY WITH REGARD TO OVERNIGHT DEWPOINTS. VARIOUS NEAR
AND SHORT TERM NWP WIDE APART ON OVERNIGHT DEWPOINTS...WHICH LIKELY
STEM FROM EXACTLY HOW LOW DEWPTS DROP TODAY WITH MIXING. AT
15Z...HSP CURRENTLY REPORTING A 28F TD. LATEST RUC13 AND HRRR
OUTPUT...AMONG OTHERS...SUGGEST DEWPOINTS WAY DOWN IN THE MID 20S
LOWLANDS THIS AFTERNOON...AND CONTINUING ALL NIGHT.
MEANWHILE...LATEST LAMP GUIDANCE KEEPS DEWPTS IN THE UPPER 30S.
NON-CONVECTIVE NWP RUN THE GAMUT IN BETWEEN...KEEPING DEWPOINTS
GENERALLY LOW/MID 30S...AND SOME A BIT HIGHER THAN THAT. PLAN ON
WATCHING AFTERNOON DEWPOINTS BEFORE MAKING A FINAL CALL ON COVERAGE
OF TONIGHT/S FROST ADVISORY...BUT RIGHT NOW ANTICIPATE PROBABLY
REMAINING CLOSE TO SOME FORM OF CONSMOS WHICH IS MORE CONSISTENT
ACROSS THE BOARD AT THIS POINT WITH TD/S RECOVERING INTO THE
MID 30S FOR THE LOWLANDS...AFTER AFTERNOON TD/S THIS AFTERNOON
MIX DOWN INTO THE LOW 30S. FROST DOES APPEAR MORE LIKELY TONIGHT
VERSUS LAST NIGHT...AND DO ANTICIPATE A FROST ADVISORY NEEDED FOR AT
LEAST SOME OF THE EASTERN MOUNTAINS COUNTIES.
MONDAY...VERY NICE AND PLEASANT DAY IS IN STORE FOR THE AREA UNDER
MOSTLY SUNNY TO PERHAPS SOME PARTLY CLOUDY SKIES...ALONG WITH WARMER
TEMPERATURES AND CONTINUED LIGHT WINDS. LATEST NAM12 IS HINTING AT
THE POSSIBILITY OF SOME LIGHT CONVECTIVE SHOWERS ALONG THE HIGHEST
RIDGES OF POCAHONTAS COUNTY AREA...BUT THE CONVERGENCE APPEARS VERY
WEAK AND WILL TREAT THIS WITH ONLY A SLIGHT RAISE OF SILENT POPS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
MODELS ARE IN AGREEMENT WITH HIGH PRESSURE EXITING THE EASTERN
MOUNTAINS BY MONDAY NIGHT. AT THE SAME TIME...WIND TURNS FROM THE
SOUTHWEST...AHEAD OF THE NEXT FRONTAL SYSTEM...TO BRING AN INCREASE
LOW LEVEL MOISTURE...SOME CLOUDS FROM WEST TO EAST. A MID LEVEL
SHORTWAVE WILL PASS ACROSS OUR NORTH TUESDAY...WHILE A WARM FRONT
LIFTS NORTH NORTHEAST ACROSS THE AREA. THESE FEATURES WILL INTERACT
TO BRING CHANCE FOR PCPN MAINLY ACROSS THE NORTHERN THIRD OF THE
AREA.
ADDITIONAL MID LEVEL SHORTWAVES ARE SUGGESTED BY MODELS TO MOVE EAST
UNDER ALMOST ZONAL FLOW BY MID WEEK. WITH THE INCREASE IN LOW LEVEL
MOISTURE...SOME FORCING FROM THE SHORTWAVES AND BEING IN THE WARM
SECTOR...KEPT HIGH CHANCE POPS MAINLY ACROSS THE NORTHERN SECTIONS
WEDNESDAY. IF FACT...IT COULD BE QUITE UNSTABLE ON WEDNESDAY WITH
SFC BASED CAPE EXCEEDING 1500 J/KG...DEEP LAYERED SHEAR UP TO 40
KNOTS MAINLY NORTH...AND PRECIPITABLE WATER AROUND 1.5 INCHES.
THE COLD FRONT WILL REACH SOUTHEAST OH...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS BY LATE WEDNESDAY NIGHT INTO EARLY THURSDAY...THEN
SPREAD NORTHWEST TO SOUTHEAST LATER THURSDAY WITH GOOD CHANCE FOR
SHOWERS AND THUNDERSTORMS. KEPT LIKELY POPS AS SUGGESTED BY THE SREF
WITH SUPPORT FROM THE GFS AND ECMWF.
THE SOUTHWEST FLOW AND ASSOCIATED WARMER AIRMASS WILL BRING A
WARMING TREND THROUGH THE PERIOD. TEMPERATURES EXPECTED TO REACH
NEAR 80 DEGREES TUESDAY...ESPECIALLY SOUTH AND WEST WITH MORE
SUNSHINE. EVEN WARMER A AFTERNOON CAN BE EXPECTED WEDNESDAY AHEAD OF
THE COLD FRONT UNDER WARM ADVECTION.
USED A BLEND OF HPC GUIDANCE AND ALL BLEND MOS GUIDANCE THROUGH THE
PERIODS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
BY THURSDAY THE COLD FRONT WILL BE EXITING THE EASTERN
MOUNTAINS...ALLOWING DRY AND FRESHER AIR TO SET IN FROM THE WEST. A
SFC HIGH PRESSURE DEVELOPS ACROSS THE GREAT LAKES...OH VALLEY INTO
WV THROUGH THE WEEKEND WITH NEAR CALM FLOW.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
SCT FLAT CUMULUS FIELD DEVELOPING THIS AFTERNOON IN HEATING/MIXING
WITH BASES IN THE 4-5KFT RANGE. LIGHT NORTH/NORTHEAST WINDS
CONTINUE TODAY.
EXPECT SOME LATE VALLEY FOG TO DEVELOP AGAIN UNDER GOOD RADIATIONAL
COOLING TONIGHT...PARTICULARLY OVER THE RIVERS...AS WINDS GO NEAR-
CALM. ALSO EXPECTING FROST TO OCCUR AS WELL...PARTICULARLY FOR
LOCATIONS NORTH AND EAST...WHICH MAY LIMIT FOG EXPANSION SOME. ALL
IN ALL...KEPT ALL LOCATIONS VFR THROUGHOUT THE OVERNIGHT HOURS
EXCEPT EKN...WHERE MVFR/IFR VIS LIKELY AFTER 06Z MON.
AS SFC HIGH PRESSURE CONTINUES OFF TO THE EAST...WIND DIRECTIONS
GRADUALLY CONTINUE TO VEER TO THE EAST. WIND SPEEDS HOWEVER WILL
REMAIN ON THE LIGHT SIDE. ANY REDUCTIONS IN VISIBILITY DURING THE
OVERNIGHT AND EARLY MORNING HOURS WILL RAPIDLY SCATTER BY 12Z-13Z
AS TEMPS QUICKLY WARM THROUGH THE MORNING HOURS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: HIGH...ASIDE FROM FOG POTENTIAL.
ALTERNATE SCENARIOS: FOG TIMING AND COVERAGE TONIGHT MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z MONDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED AT THIS TIME.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FROST ADVISORY FROM 2 AM TO 9 AM EDT MONDAY FOR WVZ006>011-
013>020-024>040-046-047.
OH...FROST ADVISORY FROM 2 AM TO 9 AM EDT MONDAY FOR OHZ066-067-075-
076-085-086.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/50
NEAR TERM...50
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...50
AREA FORECAST DISCUSSION
NWS MEDFORD OR
807 PM PDT MON MAY 19 2014
.UPDATE...SHOWERS ARE CONTINUING ACROSS INLAND AREAS THIS EVENING
AS A LOW ALONG THE NORTHERN CALIFORNIA COAST CONTINUES TO BRING
MOISTURE AND INSTABILITY INTO THE AREA. ISOLATED THUNDERSTORMS
HAVE MAINLY OCCURRED NEAR THE CASCADES EARLY THIS EVENING.
OVERALL THE ATMOSPHERE IS STABILIZING THOUGH AND THE CHANCE FOR
ADDITIONAL THUNDERSTORMS REMAINS LOW THROUGH THE REST OF THE
EVENING. HAVE UPDATED POPS OVER THE AREA TO INCREASE SHOWERS
THROUGH LATE THIS EVENING IN JACKSON COUNTY AND WESTERN JOSEPHINE
COUNTY WHERE BANDS OF SHOWERS ARE ROTATING THROUGH. EXPECT THE
BEST SHOWER ACTIVITY THIS EVENING IN KLAMATH, EASTERN DOUGLAS,
JACKSON, WESTERN JOSEPHINE AND SISKIYOU COUNTIES. SCATTERED
SHOWERS ARE ALSO POSSIBLE IN LAKE AND MODOC COUNTIES AS WELL.
SHOWERS ACTIVITY WILL GRADUALLY DECREASE FROM NORTH TO SOUTH OVER
THE AREA AS THE LOW SHIFTS FURTHER SOUTH TONIGHT.
&&
.AVIATION...BASED ON 20/00Z TAF ISSUANCE...VFR CONDITIONS WILL
PREVAIL THROUGH THIS EVENING WITH A COOL UNSTABLE ATMOSPHERE
OVERHEAD. BRIEF MVFR CIGS ARE POSSIBLE IN HEAVIER SHOWERS AND
ISOLATED TO SCATTERED THUNDERSTORMS MAINLY UNTIL 06Z...AND
ANY CONVECTIVE ACTIVITY SHOULD BE CENTERED OVER NORTHERN
CALIFORNIA...THE EAST SIDE...AND THE FOOTHILLS OF THE CASCADES. TERRAIN
OBSCURATIONS WILL BE COMMON IN THESES AREAS AS WELL. MVFR CIGS
WILL RETURN TO THE COAST THIS EVENING AND SPREAD INTO THE UMPQUA
BASIN TONIGHT WITH CLEARING TO VFR AGAIN AROUND 16Z TUESDAY
MORNING. -BPN/CC
&&
.MARINE...UPDATED 19/1430 PDT...LOW PRESSURE WILL CONTINUE TO TRACK
SOUTH OVER THE COASTAL WATERS THIS EVENING. AS THE SYSTEM MOVES
OVER THE COASTAL WATERS...EXPECT SHOWERS WITH LOCALLY GUSTY WINDS
AND CHOPPY SEAS. A THERMAL TROUGH AND OFFSHORE HIGH PRESSURE WILL
DEVELOP TUESDAY...RESULTING IN MODERATE TO STRONG NORTH WINDS AND
STEEP WIND-DRIVEN SEAS TUESDAY AND WEDNESDAY OVER THE COASTAL
WATERS. MODELS AND PRESSURE GRADIENT FORECASTS HAVE CONSISTENTLY
SUGGESTED GALE FORCE WINDS AND STEEP HAZARDOUS SEAS IN WATERS
SOUTH OF GOLD BEACH. HAVE ISSUED A GALE WATCH AND HAZARDOUS SEAS
WATCH FOR THIS AREA. ALL OTHER AREAS CAN EXPECT STRONG SMALL CRAFT
WINDS AND SEAS THROUGH THURSDAY. AT THAT TIME...WINDS AND SEAS
WILL DIMINISH AS THE THERMAL TROUGH WEAKENS. AFTER A RELATIVELY
QUIET WEEKEND...A WEAK FRONT IS EXPECTED TO APPROACH THE WATERS
EARLY NEXT WEEK. -BPN
&&
.PREV DISCUSSION... /ISSUED 232 PM PDT MON MAY 19 2014/
SHORT TERM...THE WEATHER PATTERN HAS BECOME ACTIVE ACROSS MOST OF
THE FORECAST AREA FOR THE FIRST TIME IN MORE THAN A
WEEK...COURTESY OF AN UPPER LEVEL LOW THAT IS SWINGING INTO
NORTHERN CALIFORNIA FROM THE OFFSHORE WATERS. THUNDERSTORM
ACTIVITY HAS BEEN FOCUSED OVER SOUTHERN LAKE...KLAMATH...AND MODOC
COUNTIES TODAY SO FAR...BUT STORMS ARE FORMING OVER SISKIYOU AND
KLAMATH COUNTIES NOW AND WILL LIKELY IMPACT JACKSON AND JOSEPHINE
COUNTIES LATER THIS AFTERNOON.
THE MAIN THREATS WITH THESE STORMS ARE LIGHTNING...SMALL
HAIL...GUSTY WINDS...AND BRIEF HEAVY RAIN. CURRENT MODEL DATA FROM
THE RAP13 AND HRRR 3KM SUGGESTS THUNDERSTORMS WILL FORM OVER THE
SISKIYOUS AND CASCADES AROUND 3PM AND THEN PUSH INTO THE ROGUE
VALLEY AROUND 4 TO 5 PM. OF COURSE WE CAN`T TAKE THESE MODELS
VERBATIM...BUT THIS PROVIDES A GOOD IDEA OF THE SPATIAL EVOLUTION
AND MOVEMENT OF THESE STORMS.
TONIGHT...SHOWER AND THUNDERSTORMS SHOULD DIMINISH WEST OF THE
CASCADES AND THEY WILL BE FOCUSED OVER EASTERN SISKIYOU COUNTY AND
SOUTHERN LAKE AND KLAMATH COUNTIES AS THE UPPER LOW SHIFTS TO THE
SOUTH AND EAST. HERE...A DEFORMATION ZONE TO THE NORTHEAST OF THE
LOW COULD SUSTAIN SHOWER ACTIVITY FOR MUCH OF THE NIGHT. THE LOW
WILL BE SLOW ENOUGH TO MOVE OUT THAT SHOWERS COULD AFFECT EASTERN
SISKIYOU AND MODOC COUNTIES ON TUESDAY...WITH THUNDERSTORMS
POSSIBLE IN THE AFTERNOON.
AREAS AWAY FROM MODOC AND EASTERN SISKIYOU COUNTY WILL EXPERIENCE
A WARMING AND DRYING TREND FROM TUESDAY THROUGH THURSDAY THAT WILL
BRING TEMPERATURES UP TO ABOUT 10 DEGREES ABOVE NORMAL BY
THURSDAY. THE CURRY COUNTY COAST IN PARTICULAR WILL SEE WELL ABOVE
NORMAL TEMPERATURES BY WEDNESDAY DUE TO MODERATE OFFSHORE EAST TO
NORTHEAST WINDS.
LONG TERM...FRIDAY THROUGH MONDAY...THE OPERATIONAL EC AND GFS
ARE IN SIMILAR AGREEMENT ON FRIDAY, THEN THEY BEGIN TO DIVERGE
FOR THE UPCOMING HOLIDAY WEEKEND. THE EC SHOWS AN UPPER RIDGE
BUILDING NEAR 130W SATURDAY, THEN THE RIDGE AXIS BUILDS INTO THE
PAC NW SUNDAY IN RESPONSE TO AN UPPER TROUGH DIGGING OUT NEAR
140W. THE RIDGE BREAKS DOWN ON MONDAY AS THE ABOVE MENTION UPPER
TROUGH PUSHES EAST AND WEAKENS AT THE SAME TIME. IN CONTRAST...THE
GFS SHOWS A WEST TO SOUTHWEST FLOW WITH A STRONGER UPPER LOW IN
THE GULF OF ALASKA ON SATURDAY...TRACKING IT TOWARDS VANCOUVER
ISLAND BY SUNDAY EVENING THEN MOVING SOUTH INTO OREGON/WASHINGTON
MEMORIAL DAY. OF NOTE, THE PREVIOUS GFS RUN WAS SIMILAR TO THE EC
AND THE RMOP GUIDANCE FOR NEXT WEEKEND SHOWS A LOW PROBABILITY AND
PREDICTABILITY OF THE STRONGER TROUGH. THEREFORE CONFIDENCE IN THE
GFS SOLUTION IS LOW AND WE`LL BE LEANING TOWARDS THE EC SOLUTION,
THUS KEPT POPS LOW IN THE EXTENDED. TEMPERATURES WILL BE MILDER
BUT WERE NOT EXPECTING ANY HEAT WAVE. MOST LIKELY THEY WILL BE
NEAR OR SLIGHTLY ABOVE NORMAL. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR
PZZ356-376.
SMALL CRAFT ADVISORY FOR WINDS FROM 5 AM TUESDAY TO 11 PM PDT
WEDNESDAY FOR PZZ350-356-370.
HAZARDOUS SEAS WATCH FROM TUESDAY AFTERNOON THROUGH LATE
WEDNESDAY NIGHT FOR PZZ356-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM TUESDAY TO 8
AM PDT FRIDAY FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FOR WINDS FROM 5 AM TUESDAY TO 11 PM PDT
THURSDAY FOR PZZ376.
$$
CC
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
721 AM CDT SUN MAY 18 2014
.UPDATE...
RADAR TRENDS CONTINUE TO SHOW A DECREASE IN COVERAGE ACROSS OUR
SOUTHERN COUNTIES. THIS IS FURTHER SUPPORTED BY THE LATEST HRRR
LOOP WHICH RUNS THROUGH 23Z. WILL GO AHEAD AND REDUCE POPS ACROSS
THE AREA. FURTHERMORE...WILL OPT TO INCREASE THE DECREASING CLOUD
COVER TREND ACROSS THE NORTH AS BREAKS IN THE CLOUD COVER ARE
ALREADY NOTED. UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 538 AM CDT SUN MAY 18 2014/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
VFR CONDITIONS EXPECTED THRU 19/12Z. EXPECTING A DECREASING CLOUDINESS
TREND RATHER QUICKLY THRU 18/15Z W - 18/17Z E AS WEAK DISTURBANCE MOVES
OUT OF THE AREA. MAYBE SOME SHWRS ALSO AROUND CSV THRU THIS TIME
PERIOD AT BEST...BUT WILL KEEP TAFS DRY AT BNA/CKV. AFTER DISTURBANCE
PASSAGE...EXPECT GENERALLY SKC CONDITIONS THRU THE REMAINDER WITH
SOME PASSING CLOUDS POSSIBLE...BUT NOT ENOUGH OF A SIGNIFICANT
CLOUD DECK TO REFERENCE IN TAFS. SOME MVFR FOG POSSIBLE CSV AROUND
AND AFTER 19/06Z EXPECTED PER MOISTURE POOLING/CALM WINDS.
PREV DISCUSSION.../ISSUED 333 AM CDT SUN MAY 18 2014/
DISCUSSION...
SHOWERS CONTINUE TO MOVE EASTWARD ALONG OUR FAR SOUTHERN AREAS. THIS
IS DUE TO AN EASTWARD MOVING IMPULSE THAT WILL SKIRT OUR SOUTHERN
MOST COUNTIES THIS MORNING. LATEST HRRR IS OPPOSING MUCH OF ANY
NORTHWARD MOVEMENT WITH THE PRECIP. CURRENT THINKING IS TO LEAVE
POPS OUT FOR TODAY AT BNA AND CKV. ELSEWHERE...WILL LIKELY GO WITH
30 POPS PLATEAU...60 POPS FAR SOUTH WITH LESSER VALUES AS YOU HEAD
NORTH. THESE NUMBERS COULD CHANGE AS WE APPROACH THE 4 AM ISSUANCE
BUT THAT IS THE CURRENT THINKING. OTHERWISE...THE SHOWERS SHOULD
COME TO AN END BY AFTERNOON WITH PARTIAL CLEARING ACROSS THE NORTH.
TONIGHT...MOSTLY CLEAR SKIES ARE EXPECTED AREA WIDE. SOME SFC BASED
MOISTURE WILL BE AT HAND AND WE MAY EVEN EXPERIENCE SOME PATCHY
FOG...ESPECIALLY ACROSS SOUTHERN AREAS. TEMPS WILL BE ON THE COOL
SIDE WITH THE EXPECTED LOWS TO BE IN THE 40S FOR MANY AREAS.
WARMING TREND TO BEGIN ON MONDAY AS THE WELL ADVERTISED UPPER LEVEL
RIDGING PATTERN BEGINS TO EMERGE. AFTER HIGHS TODAY IN THE MID 60S
TO LOWER 70S...WE WILL SEE HIGHS ON MONDAY REACH THE MID 70S TO
LOWER 80S. EVEN WARMER ON TUESDAY WITH HIGHS WELL INTO THE 80S FOR
MANY AREAS. AT THAT TIME...THE UPPER HIGH WILL BE OVER EAST TX WITH
A STRONG 850 MB FLOW SPREADING THE WARMTH FROM THAT AREA NE TOWARD
MIDDLE TN.
IN THE EXTENDED FCST...UPPER RIDGE WILL REACH ITS MAXIMUM EFFECT ON
THURSDAY WITH THE UPPER HIGH CENTERED OVER AL. HIGH TEMPS IN THE 80S
TO NEAR 90 CAN BE EXPECTED. ON FRIDAY...THE UPPER HIGH WILL SINK
SOUTHWARD AND THE UPPER FLOW WILL BEGIN TO FLATTEN...EVENTUALLY
TRANSITIONING INTO A NW FLOW ON SATURDAY. STILL WARM BUT TEMPS WILL
BACK DOWN A FEW DEGREES. HIGHS ON SATURDAY WILL BE GENERALLY IN THE
80 TO 85 DEGREE RANGE.
AS FOR THE PRECIP CHANCES...AIRMASS TOO DRY AND CAP TOO STRONG TO
SUPPORT ANY CONVECTION UNTIL FRIDAY. AT THAT TIME...CAP WILL WEAKEN
AS MOISTURE LEVELS RISE AND A FRONTAL BOUNDARY SAGS OUR WAY FROM THE
NORTH. WILL MAINTAIN THE LOW SHOWER AND TSTM CHANCES FOR LATE IN THE
EXTENDED.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
538 AM CDT SUN MAY 18 2014
.UPDATE...FOR 12Z AVIATION DISCUSSION.
&&
.AVIATION...12Z AVIATION DISCUSSION.
VFR CONDITIONS EXPECTED THRU 19/12Z. EXPECTING A DECREASING CLOUDINESS
TREND RATHER QUICKLY THRU 18/15Z W - 18/17Z E AS WEAK DISTURBANCE MOVES
OUT OF THE AREA. MAYBE SOME SHWRS ALSO AROUND CSV THRU THIS TIME
PERIOD AT BEST...BUT WILL KEEP TAFS DRY AT BNA/CKV. AFTER DISTURBANCE
PASSAGE...EXPECT GENERALLY SKC CONDITIONS THRU THE REMAINDER WITH
SOME PASSING CLOUDS POSSIBLE...BUT NOT ENOUGH OF A SIGNIFICANT
CLOUD DECK TO REFERENCE IN TAFS. SOME MVFR FOG POSSIBLE CSV AROUND
AND AFTER 19/06Z EXPECTED PER MOISTURE POOLING/CALM WINDS.
&&
.PREV DISCUSSION.../ISSUED 333 AM CDT SUN MAY 18 2014/
DISCUSSION...
SHOWERS CONTINUE TO MOVE EASTWARD ALONG OUR FAR SOUTHERN AREAS. THIS
IS DUE TO AN EASTWARD MOVING IMPULSE THAT WILL SKIRT OUR SOUTHERN
MOST COUNTIES THIS MORNING. LATEST HRRR IS OPPOSING MUCH OF ANY
NORTHWARD MOVEMENT WITH THE PRECIP. CURRENT THINKING IS TO LEAVE
POPS OUT FOR TODAY AT BNA AND CKV. ELSEWHERE...WILL LIKELY GO WITH
30 POPS PLATEAU...60 POPS FAR SOUTH WITH LESSER VALUES AS YOU HEAD
NORTH. THESE NUMBERS COULD CHANGE AS WE APPROACH THE 4 AM ISSUANCE
BUT THAT IS THE CURRENT THINKING. OTHERWISE...THE SHOWERS SHOULD
COME TO AN END BY AFTERNOON WITH PARTIAL CLEARING ACROSS THE NORTH.
TONIGHT...MOSTLY CLEAR SKIES ARE EXPECTED AREA WIDE. SOME SFC BASED
MOISTURE WILL BE AT HAND AND WE MAY EVEN EXPERIENCE SOME PATCHY
FOG...ESPECIALLY ACROSS SOUTHERN AREAS. TEMPS WILL BE ON THE COOL
SIDE WITH THE EXPECTED LOWS TO BE IN THE 40S FOR MANY AREAS.
WARMING TREND TO BEGIN ON MONDAY AS THE WELL ADVERTISED UPPER LEVEL
RIDGING PATTERN BEGINS TO EMERGE. AFTER HIGHS TODAY IN THE MID 60S
TO LOWER 70S...WE WILL SEE HIGHS ON MONDAY REACH THE MID 70S TO
LOWER 80S. EVEN WARMER ON TUESDAY WITH HIGHS WELL INTO THE 80S FOR
MANY AREAS. AT THAT TIME...THE UPPER HIGH WILL BE OVER EAST TX WITH
A STRONG 850 MB FLOW SPREADING THE WARMTH FROM THAT AREA NE TOWARD
MIDDLE TN.
IN THE EXTENDED FCST...UPPER RIDGE WILL REACH ITS MAXIMUM EFFECT ON
THURSDAY WITH THE UPPER HIGH CENTERED OVER AL. HIGH TEMPS IN THE 80S
TO NEAR 90 CAN BE EXPECTED. ON FRIDAY...THE UPPER HIGH WILL SINK
SOUTHWARD AND THE UPPER FLOW WILL BEGIN TO FLATTEN...EVENTUALLY
TRANSITIONING INTO A NW FLOW ON SATURDAY. STILL WARM BUT TEMPS WILL
BACK DOWN A FEW DEGREES. HIGHS ON SATURDAY WILL BE GENERALLY IN THE
80 TO 85 DEGREE RANGE.
AS FOR THE PRECIP CHANCES...AIRMASS TOO DRY AND CAP TOO STRONG TO
SUPPORT ANY CONVECTION UNTIL FRIDAY. AT THAT TIME...CAP WILL WEAKEN
AS MOISTURE LEVELS RISE AND A FRONTAL BOUNDARY SAGS OUR WAY FROM THE
NORTH. WILL MAINTAIN THE LOW SHOWER AND TSTM CHANCES FOR LATE IN THE
EXTENDED.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
333 AM CDT SUN MAY 18 2014
.DISCUSSION...
SHOWERS CONTINUE TO MOVE EASTWARD ALONG OUR FAR SOUTHERN AREAS. THIS
IS DUE TO AN EASTWARD MOVING IMPULSE THAT WILL SKIRT OUR SOUTHERN
MOST COUNTIES THIS MORNING. LATEST HRRR IS OPPOSING MUCH OF ANY
NORTHWARD MOVEMENT WITH THE PRECIP. CURRENT THINKING IS TO LEAVE
POPS OUT FOR TODAY AT BNA AND CKV. ELSEWHERE...WILL LIKELY GO WITH
30 POPS PLATEAU...60 POPS FAR SOUTH WITH LESSER VALUES AS YOU HEAD
NORTH. THESE NUMBERS COULD CHANGE AS WE APPROACH THE 4 AM ISSUANCE
BUT THAT IS THE CURRENT THINKING. OTHERWISE...THE SHOWERS SHOULD
COME TO AN END BY AFTERNOON WITH PARTIAL CLEARING ACROSS THE NORTH.
TONIGHT...MOSTLY CLEAR SKIES ARE EXPECTED AREA WIDE. SOME SFC BASED
MOISTURE WILL BE AT HAND AND WE MAY EVEN EXPERIENCE SOME PATCHY
FOG...ESPECIALLY ACROSS SOUTHERN AREAS. TEMPS WILL BE ON THE COOL
SIDE WITH THE EXPECTED LOWS TO BE IN THE 40S FOR MANY AREAS.
WARMING TREND TO BEGIN ON MONDAY AS THE WELL ADVERTISED UPPER LEVEL
RIDGING PATTERN BEGINS TO EMERGE. AFTER HIGHS TODAY IN THE MID 60S
TO LOWER 70S...WE WILL SEE HIGHS ON MONDAY REACH THE MID 70S TO
LOWER 80S. EVEN WARMER ON TUESDAY WITH HIGHS WELL INTO THE 80S FOR
MANY AREAS. AT THAT TIME...THE UPPER HIGH WILL BE OVER EAST TX WITH
A STRONG 850 MB FLOW SPREADING THE WARMTH FROM THAT AREA NE TOWARD
MIDDLE TN.
IN THE EXTENDED FCST...UPPER RIDGE WILL REACH ITS MAXIMUM EFFECT ON
THURSDAY WITH THE UPPER HIGH CENTERED OVER AL. HIGH TEMPS IN THE 80S
TO NEAR 90 CAN BE EXPECTED. ON FRIDAY...THE UPPER HIGH WILL SINK
SOUTHWARD AND THE UPPER FLOW WILL BEGIN TO FLATTEN...EVENTUALLY
TRANSITIONING INTO A NW FLOW ON SATURDAY. STILL WARM BUT TEMPS WILL
BACK DOWN A FEW DEGREES. HIGHS ON SATURDAY WILL BE GENERALLY IN THE
80 TO 85 DEGREE RANGE.
AS FOR THE PRECIP CHANCES...AIRMASS TOO DRY AND CAP TOO STRONG TO
SUPPORT ANY CONVECTION UNTIL FRIDAY. AT THAT TIME...CAP WILL WEAKEN
AS MOISTURE LEVELS RISE AND A FRONTAL BOUNDARY SAGS OUR WAY FROM THE
NORTH. WILL MAINTAIN THE LOW SHOWER AND TSTM CHANCES FOR LATE IN THE
EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 71 49 81 59 / 20 0 0 0
CLARKSVILLE 70 45 80 59 / 10 0 0 0
CROSSVILLE 66 43 73 54 / 40 0 0 0
COLUMBIA 71 51 81 60 / 40 0 0 0
LAWRENCEBURG 71 51 81 59 / 60 0 0 0
WAVERLY 70 47 81 59 / 20 0 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1039 PM CDT MON MAY 19 2014
.DISCUSSION...
NO CHANGES WITH THE UPDATE. VERY DRY LAYER AT THE MID LEVELS WILL
CONTINUE TO HELP KEEP THINGS DRY/QUIET. 41
&&
.PREV DISCUSSION... /ISSUED 231 PM CDT MON MAY 19 2014/
AT 2 PM...AN AREA OF LOW PRESSURE WAS LOCATED OVER WESTERN KANSAS
AND A DRY LINE EXTENDED ACROSS THE OK/TX PANHANDLE TO AROUND THE
BIG BEND. THE PRESSURE GRADIENT REMAINS MODERATELY TIGHT WITH
BREEZY S-SE SFC WINDS. VERY LITTLE CHANGE TO THE CURRENT FORECAST
AS UPPER LEVEL RIDGING BUILDS OVER TEXAS. THE 4KM WRF AND HRRR ALL
SHOW SOME EARLY MORNING STREAMER SHOWERS TOMORROW MORNING BUT
OTHER THAN THAT THE AREA IS EXPECTED TO REMAIN DRY THROUGH SUNDAY.
A GRADUAL WARMING TREND IS EXPECTED AS HEIGHTS SLOWLY BUILD. AN
UPPER LEVEL TROUGH WILL APPROACH THE STATE LATE IN THE WEEKEND.
THE UPPER LEVEL RIDGE WILL MOVE A BIT TO THE EAST AS THE TROUGH
APPROACHES BUT THE UPPER TROUGH LOOKS LIKE IT WILL GET SHUNTED TO
THE NORTHWEST OF THE SLOWLY RETREATING UPPER RIDGE. THE UPPER
TROUGH STILL LOOKS TO GET CLOSE ENOUGH TO PROVIDE THE AREA WITH A
SLIGHT CHANCE OF PRECIPITATION BEGINNING NEXT MONDAY. OVERALL...
RAIN CHANCES LOOK TO REMAIN LOW FOR THE NEXT 7 TO 10 DAYS WITH
TEMPERATURES NEAR NORMAL VALUES. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 70 86 70 87 67 / 10 10 10 10 10
HOUSTON (IAH) 69 86 70 86 68 / 10 10 10 10 10
GALVESTON (GLS) 72 82 73 82 73 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
726 PM CDT MON MAY 19 2014
.AVIATION...
RIDGE OF HIGH PRESSURE TO THE EAST AND SSE FLOW WILL CONTINUE
THROUGH THE PERIOD. MOISTURE HAS INCREASED AND EXPECT TO SEE
MVFR CIGS DEVELOP ACROSS THE REGION AFTER MIDNIGHT. STRONG
SUBSIDENCE INVERSION IS STILL IN PLACE AND WILL CONTINUE TO
TOMORROW AND SO EXPECT A SLOWER LIFT IN CIGS AFTER 13-15Z TIME
FRAME. SOUTH TO SOUTHEAST WINDS INCREASING AFTER 15Z AND
BECOMING GUSTY 10-15G20KT. MODELS SHOWING MORE MOISTURE
TUESDAY AND WILL LIKELY SEE A REPEAT AGAIN TOMORROW NIGHT.
45
&&
.PREV DISCUSSION... /ISSUED 231 PM CDT MON MAY 19 2014/
DISCUSSION...
AT 2 PM...AN AREA OF LOW PRESSURE WAS LOCATED OVER WESTERN KANSAS
AND A DRY LINE EXTENDED ACROSS THE OK/TX PANHANDLE TO AROUND THE
BIG BEND. THE PRESSURE GRADIENT REMAINS MODERATELY TIGHT WITH
BREEZY S-SE SFC WINDS. VERY LITTLE CHANGE TO THE CURRENT FORECAST
AS UPPER LEVEL RIDGING BUILDS OVER TEXAS. THE 4KM WRF AND HRRR ALL
SHOW SOME EARLY MORNING STREAMER SHOWERS TOMORROW MORNING BUT
OTHER THAN THAT THE AREA IS EXPECTED TO REMAIN DRY THROUGH SUNDAY.
A GRADUAL WARMING TREND IS EXPECTED AS HEIGHTS SLOWLY BUILD. AN
UPPER LEVEL TROUGH WILL APPROACH THE STATE LATE IN THE WEEKEND.
THE UPPER LEVEL RIDGE WILL MOVE A BIT TO THE EAST AS THE TROUGH
APPROACHES BUT THE UPPER TROUGH LOOKS LIKE IT WILL GET SHUNTED
TO THE NORTHWEST OF THE SLOWLY RETREATING UPPER RIDGE. THE UPPER
TROUGH STILL LOOKS TO GET CLOSE ENOUGH TO PROVIDE THE AREA WITH A
SLIGHT CHANCE OF PRECIPITATION BEGINNING NEXT MONDAY. OVERALL...
RAIN CHANCES LOOK TO REMAIN LOW FOR THE NEXT 7 TO 10 DAYS WITH
TEMPERATURES NEAR NORMAL VALUES. 43
MARINE...
LITTLE TO NO CHANGE OVER THE NEXT SEVERAL DAYS. NORTHEASTERN BASED
SURFACE HIGH PRESSURE WITH LOWER WESTERN PLAINS PRESSURE WILL
MAINTAIN A PERSISTENT LIGHT...TO OCCASIONALLY MODERATE...SOUTHEAST
FETCH ACROSS THE LOCAL WATERS. BAY WATER CONDITIONS AND GULF SEA
HEIGHTS WILL REMAIN SLIGHTLY CHOPPY TO WITHIN 2 TO 4 FEET...RESPECTIVELY.
UPPER RIDGING OVER THE GULF WILL SUPPRESS PRECIPITATION...ANY RAIN
ACTIVITY LIMITED TO JUST BRIEF NORTHERN-PASSING EARLY MORNING
SHOWERS. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 70 86 70 87 67 / 10 10 10 10 10
HOUSTON (IAH) 69 86 70 86 68 / 10 10 10 10 10
GALVESTON (GLS) 72 82 73 82 73 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...41
AVIATION/MARINE...45
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
838 AM CDT SUN MAY 18 2014
.DISCUSSION...QUICK UPDATE THIS MORNING TO MAKE MINOR ADJUSTMENTS
TO WINDS AND SKY GRIDS BASED OFF OBSERVATIONS. CLOUDS HAVE CLEARED MORE OVER
THE COASTAL BEND THIS MORNING THAN ANTICIPATED. OTHERWISE
TEMP/DEWPOINTS APPEAR FAIRLY WELL ON TRACK...AND NO OTHER
ADJUSTMENTS WERE NEEDED AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 635 AM CDT SUN MAY 18 2014/
DISCUSSION...SEE 12Z AVIATION DISCUSSION.
AVIATION...IR FOG CHANNEL IS SHOWING GREATEST CLOUD COVER WEST
AND NORTH OF TERMINALS...WITH SCATTERED MAINLY VFR CIGS OVER THE
CWFA (WHERE CIGS ARE LOCATED). THUS...AM EXPECTING SCT-BKN CLOUDS
AOA 3500 FEET EXCEPT AT KLRD WHERE CIGS MAY BE MVFR FOR A SHORT
TIME BEFORE 15Z (AND MAYBE EVEN ALICE JUST BELOW 3000 FEET).
OTHERWISE...DAYTIME HEATING BY 15Z WILL PRODUCE GUSTY SSE WINDS
DURING THE DAY DECREASING AFTER SUNSET. THEN...AM EXPECTING MVFR
CIGS TO DEVELOP AOA 19/06Z SINCE THERE WILL LIKELY BE A BIT BETTER
OF A MOISTURE PROFILE IN THE LOWER LEVELS. WINDS LESSER AN ISSUE
OVERNIGHT AND NO WIND SHEAR EXPECTED.
PREV DISCUSSION... /ISSUED 307 AM CDT SUN MAY 18 2014/
SHORT TERM (TODAY THROUGH MONDAY)...NOT MUCH CHANGE NEEDED. WEAK
UPPER RIDGE IN PLACE WITH SUBSIDENT AIR THROUGH MONDAY. MORE CLOUDS
TODAY (MAINLY IN THE MORNING)...THEN EVEN MORE ON MONDAY. SHOULD SEE
LESS WIND TODAY THAN SATURDAY AS GRADIENT A BIT WEAKER SINCE SURFACE
PRESSURES ARE NOT AS STRONG AS YESTERDAY (AT LEAST PROGGED TO BE).
OTHERWISE...NOT MUCH TO TALK ABOUT AND NOT MUCH TO CHANGE...ALTHOUGH
DID MAKE SOME MINOR ADJUSTMENTS TO TEMPERATURES HERE AND THERE
(GENERALLY ABOUT A DEGREE SOME AREAS).
MARINE (TODAY THROUGH MONDAY)...WAS GOING TO CURTAIL SCA FOR THE
GULFMEX BUT WINDS STARTED TO KICK UP. RUC WINDS NORMALLY ON THE HIGH
SIDE...BUT THIS MAY PAN OUT SINCE IT IS A BIT ON THE LOW SIDE AND
GFS/NAM MOS SHOWS WINDS UP TIL ABOUT 12Z. THUS...SCA WILL CONTINUE
AND WILL GO TIL 12Z WITH IT. AFTER THAT...WINDS SHOULD BE LESS TODAY
AND TONIGHT...BUT STILL AROUND SCEC AT TIMES.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...MID LEVEL RIDGE AXIS
SHIFTS EAST DURING FIRST HALF OF LONG TERM PERIOD WITH ATMOSPHERIC
MOISTURE LIMITED TO ROUGHLY THE LOWEST 100MB DURING THAT TIME.
NOCTURNAL LLJ WILL DEVELOP EACH NIGHT RESULTING IN INCREASING CLOUD
COVER OVERNIGHT AND CLEARING/BREEZY CONDITIONS DURING THE DAYTIME
HOURS. BY MID/LATE WEEK MID AND UPPER LEVEL MOISTURE WILL INCREASE
ACROSS THE REGION AHEAD OF A POWERFUL MID/UPPER LEVEL SYSTEM MOVING
OVER THE GREAT BASIN. 00Z GUIDANCE SUITES HAVE GREATLY SLOWED THE
EASTWARD PROGRESSION OF THIS SYSTEM AND NOW KEEP THE SYSTEM OVER SW
CONUS THROUGH NEXT WEEKEND. WAS HESITANT TO JUMP ON THIS SLOWER
PROGRESSION...BUT GFS/ECMWF/AND MOST GEFS MEMBERS ALL INDICATE
SLOWING OF THE SYSTEM. THEREFORE...HAVE TRENDED THIS FORECAST
PACKAGE TOWARDS A 00Z GUIDANCE CONSENSUS. THUS...HAVE CHANCE POPS
FOR WESTERN 2/3 OF CWA FOR FRIDAY AND SATURDAY AFTERNOONS/EVENINGS
AS VORT MAXES IN H5 TO H7 LAYER ADVECT AROUND MID LEVEL SYSTEM AND
UPPER LEVEL SUBTROPICAL JET STREAK NOSES INTO THE REGION. MAX/MIN
TEMPS THROUGH THE WEEK WILL GENERALLY BE AROUND SEASONABLE
LEVELS...WITH THICKER CLOUD COVER BY LATER IN THE WEEK TO HAVE
GREATER IMPACT ON MAX TEMPS AND STRONGER LLJ TO IMPACT MIN TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 83 68 84 70 87 / 0 0 10 10 10
VICTORIA 86 65 87 67 88 / 0 0 10 10 10
LAREDO 95 69 95 71 96 / 0 0 0 0 10
ALICE 89 66 90 68 90 / 0 0 10 10 10
ROCKPORT 81 71 81 73 84 / 0 0 10 10 10
COTULLA 93 65 94 70 93 / 0 0 0 0 10
KINGSVILLE 87 66 88 69 90 / 0 0 10 10 10
NAVY CORPUS 82 71 82 72 84 / 0 0 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
LK/84...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
635 AM CDT SUN MAY 18 2014
.DISCUSSION...SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...IR FOG CHANNEL IS SHOWING GREATEST CLOUD COVER WEST
AND NORTH OF TERMINALS...WITH SCATTERED MAINLY VFR CIGS OVER THE
CWFA (WHERE CIGS ARE LOCATED). THUS...AM EXPECTING SCT-BKN CLOUDS
AOA 3500 FEET EXCEPT AT KLRD WHERE CIGS MAY BE MVFR FOR A SHORT
TIME BEFORE 15Z (AND MAYBE EVEN ALICE JUST BELOW 3000 FEET).
OTHERWISE...DAYTIME HEATING BY 15Z WILL PRODUCE GUSTY SSE WINDS
DURING THE DAY DECREASING AFTER SUNSET. THEN...AM EXPECTING MVFR
CIGS TO DEVELOP AOA 19/06Z SINCE THERE WILL LIKELY BE A BIT BETTER
OF A MOISTURE PROFILE IN THE LOWER LEVELS. WINDS LESSER AN ISSUE
OVERNIGHT AND NO WIND SHEAR EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 307 AM CDT SUN MAY 18 2014/
SHORT TERM (TODAY THROUGH MONDAY)...NOT MUCH CHANGE NEEDED. WEAK
UPPER RIDGE IN PLACE WITH SUBSIDENT AIR THROUGH MONDAY. MORE CLOUDS
TODAY (MAINLY IN THE MORNING)...THEN EVEN MORE ON MONDAY. SHOULD SEE
LESS WIND TODAY THAN SATURDAY AS GRADIENT A BIT WEAKER SINCE SURFACE
PRESSURES ARE NOT AS STRONG AS YESTERDAY (AT LEAST PROGGED TO BE).
OTHERWISE...NOT MUCH TO TALK ABOUT AND NOT MUCH TO CHANGE...ALTHOUGH
DID MAKE SOME MINOR ADJUSTMENTS TO TEMPERATURES HERE AND THERE
(GENERALLY ABOUT A DEGREE SOME AREAS).
MARINE (TODAY THROUGH MONDAY)...WAS GOING TO CURTAIL SCA FOR THE
GULFMEX BUT WINDS STARTED TO KICK UP. RUC WINDS NORMALLY ON THE HIGH
SIDE...BUT THIS MAY PAN OUT SINCE IT IS A BIT ON THE LOW SIDE AND
GFS/NAM MOS SHOWS WINDS UP TIL ABOUT 12Z. THUS...SCA WILL CONTINUE
AND WILL GO TIL 12Z WITH IT. AFTER THAT...WINDS SHOULD BE LESS TODAY
AND TONIGHT...BUT STILL AROUND SCEC AT TIMES.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...MID LEVEL RIDGE AXIS
SHIFTS EAST DURING FIRST HALF OF LONG TERM PERIOD WITH ATMOSPHERIC
MOISTURE LIMITED TO ROUGHLY THE LOWEST 100MB DURING THAT TIME.
NOCTURNAL LLJ WILL DEVELOP EACH NIGHT RESULTING IN INCREASING CLOUD
COVER OVERNIGHT AND CLEARING/BREEZY CONDITIONS DURING THE DAYTIME
HOURS. BY MID/LATE WEEK MID AND UPPER LEVEL MOISTURE WILL INCREASE
ACROSS THE REGION AHEAD OF A POWERFUL MID/UPPER LEVEL SYSTEM MOVING
OVER THE GREAT BASIN. 00Z GUIDANCE SUITES HAVE GREATLY SLOWED THE
EASTWARD PROGRESSION OF THIS SYSTEM AND NOW KEEP THE SYSTEM OVER SW
CONUS THROUGH NEXT WEEKEND. WAS HESITANT TO JUMP ON THIS SLOWER
PROGRESSION...BUT GFS/ECMWF/AND MOST GEFS MEMBERS ALL INDICATE
SLOWING OF THE SYSTEM. THEREFORE...HAVE TRENDED THIS FORECAST
PACKAGE TOWARDS A 00Z GUIDANCE CONSENSUS. THUS...HAVE CHANCE POPS
FOR WESTERN 2/3 OF CWA FOR FRIDAY AND SATURDAY AFTERNOONS/EVENINGS
AS VORT MAXES IN H5 TO H7 LAYER ADVECT AROUND MID LEVEL SYSTEM AND
UPPER LEVEL SUBTROPICAL JET STREAK NOSES INTO THE REGION. MAX/MIN
TEMPS THROUGH THE WEEK WILL GENERALLY BE AROUND SEASONABLE
LEVELS...WITH THICKER CLOUD COVER BY LATER IN THE WEEK TO HAVE
GREATER IMPACT ON MAX TEMPS AND STRONGER LLJ TO IMPACT MIN TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 83 68 84 70 87 / 0 0 10 10 10
VICTORIA 86 65 87 67 88 / 0 0 10 10 10
LAREDO 95 69 95 71 96 / 0 0 0 0 10
ALICE 89 66 90 68 90 / 0 0 10 10 10
ROCKPORT 81 71 81 73 84 / 0 0 10 10 10
COTULLA 93 65 94 70 93 / 0 0 0 0 10
KINGSVILLE 87 66 88 69 90 / 0 0 10 10 10
NAVY CORPUS 82 71 82 72 84 / 0 0 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THIS MORNING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
307 AM CDT SUN MAY 18 2014
.SHORT TERM (TODAY THROUGH MONDAY)...NOT MUCH CHANGE NEEDED. WEAK
UPPER RIDGE IN PLACE WITH SUBSIDENT AIR THROUGH MONDAY. MORE CLOUDS
TODAY (MAINLY IN THE MORNING)...THEN EVEN MORE ON MONDAY. SHOULD SEE
LESS WIND TODAY THAN SATURDAY AS GRADIENT A BIT WEAKER SINCE SURFACE
PRESSURES ARE NOT AS STRONG AS YESTERDAY (AT LEAST PROGGED TO BE).
OTHERWISE...NOT MUCH TO TALK ABOUT AND NOT MUCH TO CHANGE...ALTHOUGH
DID MAKE SOME MINOR ADJUSTMENTS TO TEMPERATURES HERE AND THERE
(GENERALLY ABOUT A DEGREE SOME AREAS).
&&
.MARINE (TODAY THROUGH MONDAY)...WAS GOING TO CURTAIL SCA FOR THE
GULFMEX BUT WINDS STARTED TO KICK UP. RUC WINDS NORMALLY ON THE HIGH
SIDE...BUT THIS MAY PAN OUT SINCE IT IS A BIT ON THE LOW SIDE AND
GFS/NAM MOS SHOWS WINDS UP TIL ABOUT 12Z. THUS...SCA WILL CONTINUE
AND WILL GO TIL 12Z WITH IT. AFTER THAT...WINDS SHOULD BE LESS TODAY
AND TONIGHT...BUT STILL AROUND SCEC AT TIMES.
&&
.LONG-TERM (MONDAY NIGHT THROUGH SATURDAY)...MID LEVEL RIDGE AXIS
SHIFTS EAST DURING FIRST HALF OF LONG TERM PERIOD WITH ATMOSPHERIC
MOISTURE LIMITED TO ROUGHLY THE LOWEST 100MB DURING THAT TIME.
NOCTURNAL LLJ WILL DEVELOP EACH NIGHT RESULTING IN INCREASING CLOUD
COVER OVERNIGHT AND CLEARING/BREEZY CONDITIONS DURING THE DAYTIME
HOURS. BY MID/LATE WEEK MID AND UPPER LEVEL MOISTURE WILL INCREASE
ACROSS THE REGION AHEAD OF A POWERFUL MID/UPPER LEVEL SYSTEM MOVING
OVER THE GREAT BASIN. 00Z GUIDANCE SUITES HAVE GREATLY SLOWED THE
EASTWARD PROGRESSION OF THIS SYSTEM AND NOW KEEP THE SYSTEM OVER SW
CONUS THROUGH NEXT WEEKEND. WAS HESITANT TO JUMP ON THIS SLOWER
PROGRESSION...BUT GFS/ECMWF/AND MOST GEFS MEMBERS ALL INDICATE
SLOWING OF THE SYSTEM. THEREFORE...HAVE TRENDED THIS FORECAST
PACKAGE TOWARDS A 00Z GUIDANCE CONSENSUS. THUS...HAVE CHANCE POPS
FOR WESTERN 2/3 OF CWA FOR FRIDAY AND SATURDAY AFTERNOONS/EVENINGS
AS VORT MAXES IN H5 TO H7 LAYER ADVECT AROUND MID LEVEL SYSTEM AND
UPPER LEVEL SUBTROPICAL JET STREAK NOSES INTO THE REGION. MAX/MIN
TEMPS THROUGH THE WEEK WILL GENERALLY BE AROUND SEASONABLE
LEVELS...WITH THICKER CLOUD COVER BY LATER IN THE WEEK TO HAVE
GREATER IMPACT ON MAX TEMPS AND STRONGER LLJ TO IMPACT MIN TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 83 68 84 70 87 / 0 0 10 10 10
VICTORIA 86 65 87 67 88 / 0 0 10 10 10
LAREDO 95 69 95 71 96 / 0 0 0 0 10
ALICE 89 66 90 68 90 / 0 0 10 10 10
ROCKPORT 81 71 81 73 84 / 0 0 10 10 10
COTULLA 93 65 94 70 93 / 0 0 0 0 10
KINGSVILLE 87 66 88 69 90 / 0 0 10 10 10
NAVY CORPUS 82 71 82 72 84 / 0 0 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THIS MORNING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
GW/86...SHORT TERM
RH/79...LONG TERM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
302 AM EDT SUN MAY 18 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE MIDWESTERN STATES WILL DRIFT SOUTHEAST
INTO THE MID ATLANTIC REGION TONIGHT INTO MONDAY. THIS WEATHER
FEATURE WILL PROVIDE A CONTINUATION OF COOL WEATHER INTO EARLY
NEXT WEEK. IN SPITE OF THE BUILDING AREA OF HIGH PRESSURE...A
SERIES OF UPPER LEVEL DISTURBANCES WILL PASS JUST SOUTH OF THE
REGION RESULTING IN PERIODS OF CLOUDINESS...ALONG WITH THE THREAT
OF A FEW SHOWERS...MAINLY ALONG AND SOUTH OF THE VIRGINIA...NORTH
CAROLINA BORDER.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 935 PM EDT SATURDAY...
THIS EVENING 00Z RNK SOUNDING SHOWED BAND OF MOISTURE FROM AROUND
780 MB TO 728 MB WITH A WEST FLOW. KFCX 88D LOOP HIGHLIGHTED
SCATTERED SHOWERS WITH SHORTWAVE MOVING EAST ACROSS THE REGION.
THE HRRR AND RNK WRFARW PRODUCED A FEW SHOWERS IN THE WEST
TONIGHT. THE ECMWF AND GFS PRINT OUT SHOWERS IN THE SOUTHWEST LATE
TONIGHT INTO SUNDAY MORNING WITH A SHORTWAVE.
STILL LOOKS LIKE PLENTY OF CLOUDS THIS EVENING INTO SUNDAY MORNING
FOR MOST OF THE AREA. THE EVENING INSTABILITY CLOUDS FROM COLD
AIR ALOFT WILL SLOWLY DISSIPATE TONIGHT...BUT EXTENSIVE MID/HIGH
CLOUDS WILL REMAIN ACROSS THE REGION ON THE NORTH SIDE OF AN
EMBEDDED DISTURBANCE IN THE BASE OF THE DEEP UPPER TROUGH THAT
WILL TRACK JUST TO THE SOUTH OF THE NC/VA BORDER TONIGHT. THE
TIMING OF THE MOISTURE IS FASTEST AND FURTHER NORTH ON THE ECMWF
COMPARED TO THE NAM/RAP AND GFS.
ADJUSTED TEMPERATURES AND DEW POINTS WITH THE LATEST OBS AND
TRENDS. ACTUALLY RAISED DEW POINTS IN THE FOOTHILLS ALONG THE
SOUTHERN BLUE RIDGE MOUNTAINS THIS EVENING INTO TONIGHT. WITH HIGH
PRESSURE BUILDING EAST INTO WEST VIRGINIA TONIGHT INTO SUNDAY
MORNING. WILL HOLD WITH FROST ADVISORY ACROSS THE NORTHWEST...WITH
LATE NIGHT OR EARLY SUNDAY MORNING CLEARING ALLOWING TEMPERATURES
TO DROP INTO THE LOWER AND MID 30S. ELSEWHERE LOW TEMPERATURES
WILL RANGE FROM THE UPPER 30S TO THE UPPER 40S. A FEW LOCATIONS IN
PIEDMONT MAY STAY NEAR 50 DEGREES OVERNIGHT. CLOUD COVER WILL
THICKEN AND SPREAD NORTHWARD ON SUNDAY WITH UPPER DISTURBANCE
MOVING EAST ACROSS THE REGION.
AS OF 646 PM EDT SATURDAY...
UPPER LEVEL DISTURBANCE ROTATING EAST ACROSS THE REGION CREATING
ISOLATED SHOWERS THIS EVENING INTO TONIGHT. RNK WRFARW SHOWED A
FEW SHOWERS IN THE WEST UNTIL 05Z. WEST WIND WILL HINDER ANY
SHOWERS MOVING INTO THE EAST BECAUSE OF DOWNSLOPE FLOW. ADJUSTED
CLOUD COVER WITH LATEST SATELLITE IMAGES. MODIFIED TEMPERATURES
AND DEW POINTS WITH LATEST OBS AND TRENDS. THE BEST CHANCE FOR
FROST FORMATION WILL OCCUR ACROSS THE NORTH WHERE FROST ADVISORY
IN EFFECT SUNDAY MORNING. MORE ADJUSTMENTS LATER THIS EVENING.
AS OF 400 PM EDT SATURDAY...
CLOUD COVER HAS BECOME WIDESPREAD ACROSS THE FORECAST AREA THIS
AFTERNOON AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE
SOUTHWEST. RADAR INDICATING A FEW SPRINKLES ARE SURVIVING THE
PASSAGE ACROSS THE MOUNTAINS...BUT MUCH OF THE SHOWER ACTIVITY IS
DIMINISHING AS THE AIR BEGINS TO MOVE DOWNSLOPE ON THE LEE SIDE.
HIGH PRESSURE BUILDING IN FROM THE LOWER OHIO RIVER VALLEY IS
MAINTAINING A WESTERLY WIND ACROSS OUR AREA THIS AFTERNOON...AND A
TIGHTENED PRESSURE GRADIENT BETWEEN THE APPROACHING HIGH AND
DEPARTING LOW PRESSURE OVER EASTERN CANADA IS KEEPING OUR WINDS
GUSTY THIS AFTERNOON.
FOR TONIGHT...THE UPPER LEVEL DISTURBANCE WILL PASS ACROSS THE
SOUTHERN HALF OF OUR AREA...TRIGGERING LIGHT SPRINKLES MAINLY
SOUTH OF HIGHWAY 460 WHICH...IF ANYTHING...WILL BE BARELY ENOUGH
TO WET THE SURFACE. RAIN SHOWER ACTIVITY WILL EXIT THE AREA
SHORTLY AFTER MIDNIGHT...WITH DECREASING CLOUD COVER IN THE WAKE
OF THE DEPARTING SYSTEM. COLD HIGH PRESSURE WILL CONTINUE TO BUILD
UP THE OHIO RIVER VALLEY THROUGH THE NIGHT...CAUSING THE PRESSURE
GRADIENT TO RELAX AND THEREFORE WIND SPEEDS TO DROP. WITH
TEMPERATURES EXPECTED TO FALL INTO THE LOW TO MID 30S ACROSS
PORTIONS OF SOUTHEAST WEST VIRGINIA AND THE ALLEGHANY HIGHLANDS...
BELIEVE FROST FORMATION WILL BE WIDESPREAD ENOUGH TO WARRANT A
FROST ADVISORY FOR THE PREDAWN HOURS OF SUNDAY. CANNOT RULE OUT
PATCHY FROST ELSEWHERE ACROSS THE MOUNTAINS...BUT WITH CLOUD COVER
EXPECTED TO REMAIN THICKER TO THE SOUTH...FROST FORMATION SHOULD
BE MORE ISOLATED. BETTER CHANCES FOR FROST EXIST IN THE DEEPER
VALLEYS...WHERE THE COLD AIR WILL DRAIN TO AND POOL.
SUNDAY WILL NOT BE TOO DISSIMILAR TO TODAY...WITH CLOUD COVER
AGAIN INCREASING DURING THE MORNING AS YET ANOTHER UPPER LEVEL
DISTURBANCE APPROACHES FROM THE SOUTHWEST. THIS SYSTEM HOWEVER IS
EXPECTED TO PASS FURTHER SOUTH OF OUR AREA...BRINGING ONLY A
SLIGHT CHANCE OF SHOWERS AS FAR NORTH AS THE VIRGINIA NORTH
CAROLINA BORDER. LOOKING TO BE A DEGREE OR TWO WARMER FOR
AFTERNOON HIGHS COMPARED TO SATURDAY AS A MASSIVE UPPER LEVEL LOW
OVER THE GREAT LAKES RETREATS NORTH.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
AS OF 315 PM EDT SATURDAY..
THE BROAD UPPER TROUGH PATTERN WILL SLOWLY SHIFT EAST OF THE EASTERN
U.S. SUNDAY NIGHT INTO MONDAY...ALL WHILE SURFACE HIGH PRESSURE
BECOMES MORE CENTERED OVER OUR REGION. A DISTURBANCE WILL ROUND THE
BASE OF THE UPPER TROUGH SUNDAY NIGHT...WITH MOST OF THE ASSOCIATED
PRECIPITATION SOUTH OF THE AREA BY THE EVENING HOURS...AFTER
SKIRTING THE SOUTHERN QUARTER OF THE REGION DURING THE DAY SUNDAY.
WITH LIGHT WIND...COOL TEMPERATURES...AND POTENTIALLY LESS CLOUD
COVER THAN THAT EXPECTED TONIGHT...SUNDAY NIGHT WILL BE ANOTHER
NIGHT WITH FROST POTENTIAL OVER A GENEROUS PORTION OF GREENBRIER
COUNTY WV AND BATH COUNTY VA. A FROST ADVISORY MAY BE NEEDED AGAIN.
ELSEWHERE...FROST WILL BE VERY PATCHY ACROSS THE MOUNTAINS...BUT
WITH A FARTHER SOUTH EXTENT THAN EXPECTED TONIGHT THANKS TO LESS
CLOUD COVER. THIS WOULD INCLUDE THE NEW RIVER VALLEY/MOUNTAIN
EMPIRE REGIONS OF SOUTHWEST VIRGINIA AND THE NORTHERN MOUNTAINS OF
NORTH CAROLINA.
PRECIPITATION WILL BE LACKING MONDAY INTO EARLY TUESDAY AS AN UPPER
RIDGE BUILDS INTO THE AREA...AND TEMPERATURES WILL START TO MODERATE
AS WE PROGRESS INTO A SOUTHWEST...WARM AIR ADVECTION FLOW. BY
TUESDAY AFTERNOON...HIGHS WILL BE RANGING FROM THE LOW TO MID 70S IN
THE MOUNTAINS AND MID TO UPPER 70S ACROSS THE PIEDMONT.
BY LATE TUESDAY AFTERNOON INTO TUESDAY EVENING...A SHORTWAVE TROUGH
WILL MOVE THROUGH PENNSYLVANIA. THE SOUTHERN EXTENT OF ITS
ASSOCIATED ENERGY IS PROGGED TO ENCOUNTER THE NORTHERN EXTENT OF THE
UPPER RIDGE. THIS INTERACTION WILL LIMIT HOW MUCH IMPACT THE SYSTEM
HAS ON THE NORTHERN PART OF THE FORECAST AREA. FOR NOW WILL ONLY
OFFER ISOLATE SHOWERS NEAR THE I-64 CORRIDOR OF WV AND VA DURING
THIS TIME PERIOD. THIS FEATURE IS EXPECTED TO BE EAST OF THE REGION
BY LATE TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 1235 PM EDT SATURDAY...
WEDNESDAY INTO WEDNESDAY NIGHT...ANOTHER...AND STRONGER...SHORTWAVE
TROUGH WILL MOVE ALONG THE U.S./CANADIAN BORDER AND ACT AS THE
CATALYST TO ALLOW A TRANSITION FROM UPPER LEVEL RIDGING OVER OUR
REGION TO ONE OF NORTHWEST FLOW AND GENERAL TROUGHINESS OVER THE
NORTHEAST U.S. THE UPPER RIDGE OVER OUR REGION WILL RETROGRADE TO
THE CENTRAL U.S.
THIS NEW REGIME WILL ALSO PLACE A BAROCLINIC ZONE OVER...OR JUST
NORTH OF THE AREA. THE RESULT WILL BE PATTERN THAT WILL BE MORE
CLOUDY THAN CLEAR WITH DAILY CHANCE OF ISOLATED TO SCATTERED SHOWERS
AND STORMS. ALSO...THE FLOW PATTERN WILL BE PRONE TO WELCOMING ANY
POTENTIAL THUNDERSTORM COMPLEXES THAT FORM OVER THE LOWER OHIO
VALLEY INTO AT LEAST THE WESTERN EXTENT OF THE FORECAST AREA. THE
DEGREE TO WHICH ANY MAKE IT EAST OF THE BLUE RIDGE VARY FROM SYSTEM
TO SYSTEM.
TEMPERATURES WILL CONTINUE TO TREND WARMER ON WEDNESDAY FROM EARLIER
IN THE WEEK...BUT TAKE A SLOW TURN COOLER AS CLOUDS AND
PRECIPITATION BECOME MORE FREQUENT IN THE FORECAST...AND THE HIGHER
HEIGHTS SHIFT WEST.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 200 AM EDT SUNDAY...
SATELLITE IMAGERY INDICATES THAT MOST OF THE FORECAST REGION SITS
UNDER A LAYER OF MID LEVEL CLOUDS THIS MORNING...WITH BASES
RANGING FROM 4KFT TO 7KFT...LOW END VFR. CLOUD COVER IS DOING A
GOOD JOB OF INSULATING THE AREA...KEEPING TEMPERATURES WARMER
WHICH...COMBINED WITH THE LIGHT AND DRY NORTHWESTERLY FLOW...IS
PREVENTING ANY SIGNIFICANT VISIBILITY DROPS.
FOR TODAY...MODELS IN VERY GOOD AGREEMENT THAT SHOWER ACTIVITY
ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE PASSING EAST ACROSS
SOUTHERN TENNESSEE WILL REMAIN MAINLY SOUTH OF THE FORECAST
AREA...MAYBE A FEW SPRINKLES FROM THE NORTH CAROLINA MOUNTAINS
THROUGH KDAN AT MOST. ENOUGH INSTABILITY WILL REMAIN IN THE MID
LEVELS OF THE ATMOSPHERE TO MAINTAIN SCT TO BKN STRATOCU THROUGH
THE DAY INTO LATE EVENING AREAWIDE. WHILE HIGH PRESSURE WILL
REMAIN CENTERED OVER OHIO...A FINGER OF THE HIGH WILL BUILD
SOUTHWARD ALONG THE EASTERN FACE OF THE APPALACHIANS TO SHIFT
WINDS FROM NORTHERLY LATER THIS MORNING...TO SOUTHEASTERLY BY
SUNRISE MONDAY. A LACK OF ANY SIGNIFICANT PRESSURE GRADIENT WILL
KEEP WINDS SPEEDS LIGHT THROUGH THE TAF PERIOD.
HIGH CONFIDENCE IN VFR CEILINGS THROUGH THE TAF VALID PERIOD.
HIGH CONFIDENCE IN VFR VISIBILITIES THROUGH THE TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPEED THROUGH THE TAF VALID PERIOD.
EXTENDED AVIATION DISCUSSION...
UPPER TROUGH RESPONSIBLE FOR THE COOL WEATHER IS EXPECTED TO MOVE
AWAY FROM THE AREA EARLY NEXT WEEK. THIS WILL RESULT IN DRIER
CONDITIONS UNDER NW FLOW ALOFT...PROVIDING MAINLY VFR FOR MONDAY
AND TUESDAY. HOWEVER...A BAROCLINIC ZONE WILL SET UP OVER THE AREA
TOWARD MID-WEEK AND LINGER THROUGHOUT THE REMAINDER OF THE WEEK.
DISTURBANCES EMBEDDED WITHIN AN UNSTABLE NW FLOW ALOFT WILL LIKELY
BRING SCT SHRA/TSRA TO THE REGION DURING THE AFTERNOON/EVENING
WED-FRI. RIGHT NOW...WED AND THU APPEAR TO BE THE MOST ACTIVE DAYS
FOR CONVECTION. THE SYNOPTIC PATTERN SHOULD PROVIDE MOSTLY VFR
CONDITIONS OTHERWISE...OUTSIDE SHRA/TSRA ACTIVITY...WHEN BRIEF
PERIODS OF MVFR-IFR CIGS AND VSBYS MAY OCCUR ALONG WITH GUSTY AND
ERRATIC WINDS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR VAZ020.
NC...NONE.
WV...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR WVZ045.
&&
$$
SYNOPSIS...NF
NEAR TERM...KK/NF
SHORT TERM...DS
LONG TERM...DS
AVIATION...NF/RAB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
904 PM CDT MON MAY 19 2014
.UPDATE...
ISSUED AT 904 PM CDT MON MAY 19 2014
THE MAIN FOCUS THIS EVENING HAS BEEN ON THE POTENTIAL FOR FLOODING
ACROSS NORTH CENTRAL WISCONSIN WHERE MAINLY LIGHT TO MODERATE RAIN
HAS BEEN FALLING FOR MUCH OF THE DAY...BUT A ROUND OF CONVECTION
CAME THROUGH EARLIER AND NOW HAS RETREATED TO THE SOUTH ACROSS
CLARK COUNTY. ALL SHORT TERM MESO/SYNOPTIC GUIDANCE HAD THIS
CONVECTION WELL TO THE NORTHEAST BY NOW...BUT IT APPEARS TO BE
HANGING ON TO THE NOSE OF THE LOW LEVEL JET/MOISTURE TRANSPORT
THAT IS ANGLING UP FROM THE SOUTHWEST INTO THE CONVECTION. BASED
ON THE PAST HOUR/TWO OF RADAR LOOPS...IT APPEARS THAT THERE HAS
BEEN A SLIGHT SHIFT NORTHEAST OF THIS MAIN BAND OF
CONVECTION...BUT IT WILL LIKELY NOT TRACK TO THE NORTHEAST TOO
QUICKLY. THE 20.01Z RAP DOES TAKE THE LLJ TO THE EAST AFTER
MIDNIGHT...SO EXPECT THAT THE PRECIPITATION SHOULD SHIFT AWAY FROM
CLARK/TAYLOR AT THAT POINT. FLASH FLOOD GUIDANCE IS AROUND 3
INCHES AND IT DOES NOT LOOK LIKE WE WILL HIT THAT OVER A SHORT
ENOUGH OF A TIME PERIOD TO BE ISSUING WARNINGS AT THIS POINT.
TO THE SOUTHWEST OF THIS AREA...HAVE HAD SOME SCATTERED RAIN
SHOWERS AND DRIZZLE DEVELOPED UNDER THE LLJ AND WILL LIKELY
CONTINUE UNTIL THE LLJ SHIFT EAST LATER ON. THERE IS SOME QUESTION
ABOUT WHETHER ANY FOG WOULD FORM OVERNIGHT...BUT CLOUD COVER
EXTENDS WEST THROUGH MUCH OF WESTERN MINNESOTA AND IOWA. IF SKIES
CAN CLEAR OUT...THEN THE LIGHT WINDS AND RECENT RAIN WILL LIKELY
LEAD TO SOME FOG FORMATION BUT CHANCES OF IT OCCURRING ARE BETTER
TO THE WEST.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 215 PM CDT MON MAY 19 2014
LOW LEVEL WARM AIR ADVECTION/MOISTURE TRANSPORT ARE THE MAIN DRIVERS
FOR AREAS OF PCPN MOVING ACROSS THE REGION THIS AFTERNOON. SOME
THUNDER WITH THE SHOWERS...DESPITE THE PCPN RUNNING OUT OF
THE MAIN CAPE AXIS ACROSS THE PLAINS/WESTERN MN.
THE LOW LEVEL THERMODYNAMICS AND NOSE OF THE MOISTURE TRANSPORT
SHIFT ACROSS NORTHEAST WI TONIGHT...AND SO WILL THE FAVORED AREAS
FOR PCPN. INSTABILITY DOES INCREASE OVERNIGHT...WITH MUCAPES FROM 500-
1000 J/KG PER THE GFS/NAM. THIS COULD EXTEND SOME PCPN CHANCES BACK
TO THE SOUTHWEST...NEAR A WEAK TROUGH/FRONT ON THE LEADING EDGE OF
AN UPPER LEVEL SHORTWAVE. THE HIGHER QPF AND BEST CHANCES WILL BE TO
THE NORTH TONIGHT/OVERNIGHT...BUT WILL LIKELY HOLD ONTO SOME PCPN
CHANCES TO ACCOUNT FOR THE POTENTIAL ASSOCIATED WITH THE
BOUNDARY/INSTABILITY.
ON TUESDAY...THIS BOUNDARY LAYS UP WEST TO EAST ACROSS CENTRAL
IA/SOUTHERN WI...AND COULD SERVE AS A SHOWER/STORM FOCUS LATER IN
THE AFTERNOON. THE GFS AND NAM SUGGEST 2000+ J/KG SBCAPE INTO
SOUTHEAST MN/WESTERN WI BY 18Z...WITH 50 KTS OF 0-6 KM SHEAR. THE
SBCAPE IS BASED OFF OF LOW/MID 60S TDS WORKING INTO CENTRAL WI ON
WI. THIS LOOKS OVERDONE BASED ON WHAT IS OCCURRING OUT TO THE
WEST...AND THE LACK OF EVAPORTRANSPIRATION FROM CROPS TO AID IN
HIGHER TDS. DEWPOINTS IN THE UPPER 50S LOOK MORE LIKELY...THUS
LOWERING CAPE QUITE A BIT. FORCING MECHANISM ALSO LOOKS TO BE JUST
SOUTH OF THE FORECAST AREA...BUT CLOSE ENOUGH THAT PCPN CHANCES ARE
WARRANTED FOR PARTS OF NORTHEAST IA/SOUTHWEST WI.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 215 PM CDT MON MAY 19 2014
THE GFS AND ECMWF FAVOR GOING ZONAL TO RIDGING FOR THE LATER PART OF
THE WORK WEEK INTO THE UPCOMING WEEKEND WITH THE UPPER LEVEL FLOW.
AT THE SURFACE...HIGH PRESSURE MEANDERS DOWN FROM SOUTHERN
CANADA...SLIDING ACROSS THE REGION...AND GRADUALLY MOVING OVER THE
OH RIVER VALLEY BY 12Z SAT. A DRY...VERY PLEASANT FEW DAYS SHOULD
RESULT...WITH HIGHS AT OR ABOVE THE SEASONABLE NORMALS.
FINALLY...SOME NICE SPRING DAYS.
SOME DIFFERENCES IN THE MODELS FOR THE END OF THE WEEKEND...WITH THE
EC SUGGESTING AN UPPER LEVEL SHORTWAVE TROUGH COULD SLIDE ACROSS
NORTHERN PARTS OF THE REGION SUNDAY NIGHT-MONDAY. THE GFS FAVORS
RIDGING. HOWEVER...WITH THE SFC HIGH OFF TO THE EAST...SOUTHERLY
FLOW ON ITS BACKSIDE PUSH WARM/MOIST AIR TOWARD THE REGION. THIS
THERMODYNAMIC FORCING COULD RESULT IN SOME
SHOWERS/STORMS...REGARDLESS OF ANY UPPER LEVEL AID. WILL HOLD WITH
CONSENSUS SOLUTION FOR DETAILS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 639 PM CDT MON MAY 19 2014
LOW CONFIDENCE FORECAST FOR TONIGHT AS THE POTENTIAL IS THERE FOR
CONDITIONS TO DROP TO IFR FROM THEIR CURRENT VFR POSITIONS. A BAND
OF DRIZZLE/RAIN APPEARS TO BE MOVING EAST ACROSS SOUTH CENTRAL
MINNESOTA AND SHOULD BE INTO RST SHORTLY. FURTHER WEST FROM THIS
BAND...SKY CONDITIONS ARE MAINLY VFR AT 4KFT UNTIL YOU REACH THE
TROUGH IN THE EASTERN DAKOTAS. IN AREAS WHERE SKIES CLEAR OUT
OVERNIGHT AHEAD OF THIS FRONT...SOME FOG WILL LIKELY DEVELOP DUE
TO LIGHT WINDS AND FAIRLY WIDESPREAD RAINS THAT OCCURRED TODAY.
FOR NOW...THIS VFR CLOUD COVER LOOKS EXTENSIVE AND THINKING IS
THAT IT WILL BE TOUGH TO BREAK THIS OVERNIGHT. SO...OUTSIDE OF THE
PERIOD OF DRIZZLE THIS EVENING...HAVE GONE WITH A BIT MORE
OPTIMISTIC FORECAST FOR TONIGHT. CONDITIONS IMPROVE TOMORROW AS
THE TROUGH MOVES THROUGH AND DRIER AIR MOVES IN WITH WINDS STAYING
LIGHT THROUGH THE DAY.
&&
.HYDROLOGY...
ISSUED AT 331 AM CDT MON MAY 19 2014
WATER LEVELS ON THE MISSISSIPPI ARE BEGINNING TO GO DOWN WITH SOME
LOCATIONS FALLING BELOW FLOOD STAGE FROM LA CROSSE AND NORTH.
MINOR FLOODING WILL CONTINUE UNTIL LATE IN THE WEEK FOR SITES
SOUTH OF LA CROSSE WHERE THE CREST IS JUST NOW ARRIVING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...HALBACH
HYDROLOGY....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 PM CDT SAT MAY 17 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 337 PM CDT SAT MAY 17 2014
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED AN UPPER
LEVEL TROUGH EXTENDING FROM NEAR HUDSON BAY SOUTH INTO THE EASTERN
GREAT LAKES. THE TROUGH WAS MAKING PROGRESS TO THE EAST AS RIDGING WAS
BUILDING INTO THE ROCKIES. THE POSITION OF THESE TWO FEATURES
PLACES THE UPPER MISSISSIPPI RIVER VALLEY IN NORTHWEST FLOW ALOFT
WITH WEAK EMBEDDED SHORTWAVES NOTED. THE COMBINATION OF THE
SHORTWAVES AND DEEP MIXING HAS ALLOWED FOR THE DEVELOPMENT OF
SCATTERED TO BROKEN CUMULUS THIS AFTERNOON WITH A FEW RETURNS
NOTED ON RADAR OVER PORTIONS OF SOUTH CENTRAL MINNESOTA WHERE
ENHANCE CUMULUS MAY PRODUCE A FEW LIGHT SPRINKLES. SOME OF THESE
LIGHT SPRINKLES MAY MAKE IT INTO PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA BUT THEY WILL QUICKLY DIE OFF LATE THIS
AFTERNOON WITH THE LOSS OF DAYTIME HEATING. WITH SLIGHTLY WARMER
AIR OVER THE REGION THIS EVENING AND A SLIGHTLY TIGHTER PRESSURE
GRADIENT WE SHOULDN/T HAVE FROST CONCERNS TONIGHT WITH
TEMPERATURES BOTTOMING OUT IN THE UPPER 30S OVER NORTH CENTRAL
WISCONSIN TO THE LOWER 40S ACROSS NORTHEAST IOWA. WILL HAVE TO
KEEP A CLOSE EYE ON EASTERN TAYLOR COUNTY WHERE TEMPERATURES COULD
FALL INTO THE MID 30S AND FROST WOULD BE POSSIBLE IN THESE AREAS.
ON SUNDAY...UPPER RIDGING WILL BUILD INTO THE REGION WITH PARTLY TO
MOSTLY SUNNY SKIES EXPECTED. THE PRESSURE GRADIENT WILL CONTINUE
TO TIGHTEN OVER THE UPPER MISSISSIPPI RIVER VALLEY ON SUNDAY AS
SURFACE HIGH PRESSURE SLIDES OVER THE OHIO RIVER VALLEY AND LOW
PRESSURE DEEPENS OVER THE HIGH PLAINS/BLACK HILLS AREA. PLAN ON
SOUTHWEST WINDS OF 10 TO 17 MPH WITH GUSTS APPROACHING 28 MPH
DURING THE AFTERNOON HOURS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 PM CDT SAT MAY 17 2014
THE UPPER RIDGE WILL FLATTEN AND SLIDE EAST ON MONDAY AS A
SHORTWAVE TROUGH LIFTS NORTHEAST ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY. THE BEST 925-850 MB MOISTURE TRANSPORT LOOKS TO PUSH
INTO THE REGION MONDAY AFTERNOON INTO MONDAY EVENING LEADING TO
SHOWERS AND THUNDERSTORMS. THE BULK OF THIS ACTIVITY SHOULD OCCUR
NORTH F THE INTERSTATE 90 CORRIDOR WITH AN ELEVATED MIXED
LAYER...CENTERED AROUND 700 MB...HELPING TO EFFECTIVELY CAP
CONVECTIVE ACTIVITY. THE BULK OF THE ENERGY FROM THIS SYSTEM
PASSES NORTH OF THE FORECAST AREA AS LOW PRESSURE DEEPENS OVER
SOUTHERN MANITOBA INTO SOUTHWEST ONTARIO. THE LOW THEN SLIDES OVER
FAR NORTHERN LAKE SUPERIOR/SOUTHERN ONTARIO ON TUESDAY AS A BOUNDARY
SAGS SOUTH ACROSS THE FORECAST AREA. WE DO BUILD SOME SURFACE
BASED CAPE ON TUESDAY AS TEMPERATURES CLIMB INTO THE MID TO
POSSIBLY UPPER 70S. FORECAST SOUNDINGS SUGGEST SURFACE BASED CAPE
VALUES COULD APPROACH 1300 J/KG. CANNOT RULE OUT SCATTERED SHOWERS
AND THUNDERSTORMS DEVELOPING OVER NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN TUESDAY AFTERNOON INTO TUESDAY EVENING BUT THERE ISN/T
MUCH UPPER LEVEL SUPPORT...WITH WEAK SUBSIDENCE OVER THE REGION.
THERE IS A SUBTLE SHORTWAVE THAT MOVES OVER THESE AREAS LATE
TUESDAY AFTERNOON INTO TUESDAY EVENING SO THIS MAY PROVIDE JUST
ENOUGH SUPPORT TO SPARK A FEW SHOWERS AND STORMS. BEYOND
TUESDAY...HIGH PRESSURE APPEARS TO BE THE DOMINANT WEATHER
FEATURE THROUGH THE END OF THE WORK WEEK WITH MAINLY DRY AND QUIET
WEATHER EXPECTED. HIGH TEMPERATURES WILL BE VERY PLEASANT RANGING
FROM THE UPPER 60S TO LOWER 70S. THIS TREND COULD CONTINUE RIGHT
INTO THE MEMORIAL DAY WEEKEND. EXTENDED FORECAST MODELS SUGGEST
THERE COULD BE SOME LOW CHANCES FOR SHOWERS AND STORMS SATURDAY
INTO SUNDAY. LEANED TOWARD A MODEL CONSENSUS BLEND ON SATURDAY BUT
WE WILL HAVE TO SEE HOW THE RIDGE EVOLVES THE NEXT FEW MODEL RUNS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM CDT SAT MAY 17 2014
VFR CONDITIONS THROUGH THE PERIOD. WINDS WILL INCREASE IN THE
MORNING AS DEEPER MIXING OCCURS. WEATHER IS EXPECTED TO MOVE IN
FROM THE WEST MONDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 337 PM CDT SAT MAY 17 2014
WATER LEVELS ALONG THE MISSISSIPPI RIVER WILL CONTINUE TO RUN HIGH
THROUGH THE WEEKEND AND INTO NEXT WEEK. SOME MINOR FLOODING IS
ALREADY OCCURRING OR EXPECTED TO OCCUR INTO NEXT WEEK.
FOR MORE DETAILED INFORMATION...LOOK ON OUR INTERNET PAGE AT
WWW.WEATHER.GOV/LACROSSE. CLICK ON THE NEWS STORY AT THE TOP OF
THE PAGE PERTAINING TO THE MISSISSIPPI RIVER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...BAUMGARDT
HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
343 AM MDT TUE MAY 20 2014
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 340 AM MDT TUE MAY 20 2014
MAIN CONCERN TODAY WILL BE THREAT OF THUNDERSTORMS AND SEVERE
WEATHER.
LATEST RADAR SHOWS A FEW SHOWERS AND STORMS MOVING QUICKLY
NORTHEAST ACROSS THE NORTHEAST PLAINS EARLY THIS MORNING. MOST OF
THESE WILL BE EXITING THE STATE BY OR SHORTLY AFTER DAYBREAK
ALTHOUGH CANT TOTALLY RULE OUT AN ISOLATED STORM LINGERING BEHIND
AS CURRENT CONVECTION HAS BEEN DEVELOPING ON JET STREAK/CLOUD
PLUME STRETCHING OUT OF THE DESERT SOUTHWEST. OTHERWISE LOOK FOR A
CLOUDY START TO THE DAY ON THE PLAINS WITH WIDESPREAD STRATUS
DECK...WHILE MOSTLY CLEAR SKIES PREVAIL IN THE MOUNTAINS.
THE CLOUDS TO THE NORTH AND SUNSHINE TO THE SOUTH WILL INCREASE
THE BAROCLINICITY ON THE HIGH PLAINS AND AID DEVELOPMENT OF A
CYCLONIC CONVERGENCE ZONE. AT THIS TIME...THE FRONTAL SURGE HAS
PUSHED SUBSTANTIALLY SOUTHWARD INTO SOUTHEAST COLORADO...SO MOST
LIKELY LOCATION OF LOW LEVEL CONVERGENCE ZONE THIS AFTERNOON WILL
BE NEAR THE PALMER DIVIDE. BELIEVE THE RAP IS CONSIDERABLY
OVERDOING THE MIXING AND DRYING...WHILE LATEST NAM IS DOING A
BETTER JOB. AS A RESULT...HIGHEST RISK OF STORM INITIATION WILL BE
OVER THE ELEVATED TERRAIN AND PALMER DIVIDE AS THE NORTHEAST
PLAINS WILL LIKELY REMAIN CAPPED WITH RESPECT TO SURFACE BASED
CONVECTION THROUGH MOST OF THE AFTERNOON. IF THE STORMS GET GOING
IN/NEAR THE HIGHER TERRAIN LATE THIS AFTERNOON...THEY SHOULD BE
ABLE TO HELP BREAK THE CAP AS THEY MOVE QUICKLY NORTHEAST ACROSS
THE PLAINS EARLY THIS EVENING. THERE IS SUFFICIENT CAPE...NEAR
1000 J/KG...WITH MID 40S DEWPOINTS FOR SEVERE STORMS WITH LARGE
HAIL BEING THE PRIMARY THREAT. LCLS ARE A BIT HIGH FOR TORNADO
PRODUCTION TODAY BUT STILL CANT RULE OUT AN ISOLATED SPINUP WITH
ENHANCED LOW LEVEL VORTICITY WHERE THE CONVERGENCE ZONE SETS UP.
STORMS WILL LIKELY CONTINUE THROUGH THE EVENING AND THEN GRADUALLY
DIMINISH FROM WEST TO EAST ACROSS THE PLAINS AFTER MIDNIGHT. COULD
SEE AREAS OF STRATUS REDEVELOP OVERNIGHT WITH MOIST EAST/SOUTHEAST
LOW LEVEL FLOW.
MOUNTAIN AREAS WEST OF THE FRONT RANGE WILL LIKELY STAY DRY
THROUGH TONIGHT WITH A MUCH DRIER AIRMASS HOLDING IN PLACE THERE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 340 AM MDT TUE MAY 20 2014
INCREASING RAIN CHANCES EXPECTED THROUGH THE REST OF THE WEEK AS THE
UPPER LOW OVER THE GREAT BASIN WILL BE SINKING SOUTH INTO SOUTHERN
CALIFORNIA AND ARIZONA WEDNESDAY. THIS WILL KEEP SOUTHERLY FLOW
OVER THE STATE AS IT REMAINS OVER THE SOUTHWEST THROUGH SATURDAY
MORNING BEFORE LIFTING NORTH.
HAVE STUCK TO MORE OF A NAM SOLUTION FOR WEDNESDAY WHICH WOULD
HAVE MORE MOISTURE AND UPSLOPE FLOW OVER THE PLAINS THAN THE GFS.
SOUTHEASTERLY WINDS AT THE SURFACE AND SOUTHWEST ALOFT WILL BE
INCREASING AVAILABLE MOISTURE WITH MODELED CAPES IN THE 1200-2000
J/KG RANGE. WITH THIS INSTABILITY AND AVAILABLE SHEAR...LOOKING
FOR MORE NUMEROUS THUNDERSTORMS ACROSS THE AREA WEDNESDAY WITH A
GREATER CHANCE OF SEVERE STORMS. LARGE HAIL...DAMAGING STRONG
WINDS AND TORNADOES ARE ALL A POSSIBILITY. DIFFERENCES IN MODELS
HAVE VARIED AREAS WITH MOST CONCERN FOR SEVERE WEATHER AT THIS
TIME. WILL LIKELY SEE STORMS FIRING OVER THE HIGHER TERRAIN AND
FOOTHILLS THEN SPREAD NORTHEAST OVER THE PLAINS THROUGH THE DAY
AND EVENING.
LOOKING FORWARD...MODELS SHOWING INCREASING PRECIPITABLE WATER
VALUES AS WELL AS AN INCREASE IN 700 MB SPECIFIC HUMIDITIES.
AVERAGE PW VALUE FOR DENVER THIS TIME OF YEAR IS AROUND 0.6". WE
BEGIN AROUND THAT VALUE...THEN MODELS HAVE VALUES NEAR 0.8" BY
SATURDAY. LOOKING AT 700 MB SPECIFIC HUMIDITY...THERE IS A PLUME
OF HIGHER VALUES MOVING UP INTO NEW MEXICO WEDNESDAY INTO
THURSDAY...WITH A MORE PROMINENT PLUME MOVING TOWARD THE STATE
FROM FRIDAY INTO THE WEEKEND. VALUES INCREASE TO THE 7-8.3 G/KG
RANGE FRIDAY. HOWEVER EACH MODEL HAS SMALL AREAS OF DRYING MOVING
OVER THE STATE AT DIFFERENT TIMES...AS WELL AS 700MB WINDS MOVING
BETWEEN A WETTER SOUTHEAST DIRECTION TO A DRYING SOUTHWEST
DIRECTION AT TIMES. SO OVERALL...LOOKING AT AN INCREASE IN SHOWERS
AND THUNDERSTORMS THROUGH THE WEEKEND...WITH A BETTER CHANCE OF
HEAVY RAIN FROM SOME OF THE STRONGER STORMS. WINDSPEEDS ALOFT ARE
BECOMING LIGHTER WHICH MAY ALLOW FOR SLOWER MOVING THUNDERSTORMS. THE
PERIODS OF UPSLOPE WILL FOCUS OUT ATTENTION ON THE FOOTHILLS AND
URBAN CORRIDOR. ONE GOOD THING HOWEVER...IS SOME OF THE RECENT
MODELS ARE MOVING THEIR FOCUS OF PRECIPITATION FURTHER EAST OVER
THE PLAINS...BUT THIS IS AGAIN GOING TO DEPEND ON THE MID LEVEL
WINDS. BEST DAY FOR HEAVIER RAIN POTENTIAL LOOKS TO BE
FRIDAY...HAVE INCREASED SHOWER AND THUNDERSTORMS CHANCES TO
LIKELY. IN TERMS OF SNOWMELT...TEMPERATURES WON`T BE TOO QUICK TO
WARM UP AND GENERALLY HOLDING STEADY EACH DAY AND NIGHT EXTREMES.
EXPECT NEAR OR SLIGHTLY COOLER MAX TEMPS AND NEAR NORMAL MIN TEMPS
FOR THE PERIOD.
THE UNSETTLED PATTERN IS EXPECTED CONTINUE THROUGH THE HOLIDAY
WEEKEND AS THE UPPER LOW MOVES ACROSS THE STATE AND EAST ON
MONDAY. SOME WRAPAROUND MOISTURE WILL LIKELY KEEP SHOWERS IN THE
FORECAST THROUGH MONDAY AS WELL...ALTHOUGH SLIGHTLY DRIER.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 340 AM MDT TUE MAY 20 2014
CEILINGS RANGE ANYWHERE FROM 2000-5000 FT AGL ACROSS THE FRONT
RANGE AIRPORTS...AND EXPECT THOSE TO HOLD MAINLY IN THAT LEVEL
THROUGH 15Z. SHOULD THEN BEGIN TO SEE EROSION OF STRATUS DECK WITH
DAYTIME HEATING 15Z-18Z WITH VISUAL LANDING CONDITIONS DEVELOPING.
STORM INITIATION IS EXPECTED TO HOLD OFF UNTIL 21Z-23Z...MOST
LIKELY LEANING TOWARD THE LATER TIME GIVEN STRENGTH OF CAP IN
PLACE. CHANCE OF STORMS IS AROUND 30 PERCENT CENTERED ON THE 23Z-
02Z TIME FRAME. ISOLATED SEVERE STORMS POSSIBLE WITH LARGE HAIL
BEING THE PRIMARY THREAT. LIGHT NORTH WINDS WILL TRANSITION TO
EAST/SOUTHEAST AND INCREASE TO AROUND 15 KTS WITH GUSTS AROUND 22
KTS POSSIBLE BY LATE AFTERNOON. THEN VARIABLE WINDS POSSIBLE
OVERNIGHT WITH DENVER CYCLONE IN VICINITY.
&&
.HYDROLOGY...
ISSUED AT 340 AM MDT TUE MAY 20 2014
SNOWMELT WILL CONTINUE TODAY WITH MOUNTAIN TEMPS ONLY A COUPLE
DEGREES COOLER THAN YESTERDAY. A FEW SMALL STREAMS LIKE MUDDY AND
TROUBLESOME CREEKS HAVE RISEN...BUT NOT EXPECTED TO CAUSE
PROBLEMS AT THIS TIME. STRONGER STORMS COULD PRODUCE A QUICK HALF
INCH OF RAIN BUT STORMS WILL BE MOVING ALONG AT CLOSE TO 35 MPH
WHICH WILL LIMIT THREAT OF ANY SIGNIFICANT RAINFALL TOTALS.
WEDNESDAY STORM ACTIVITY IS EXPECTED TO BE MORE WIDESPREAD ACROSS
THE AREA. A STRONGER STORM WILL BE ABLE TO PRODUCE BRIEF MODERATE
RAIN OVER THE FOOTHILLS AND URBAN CORRIDOR OF HALF TO THREE
QUARTERS OF AN INCH IN 30 MINUTES....ALONG WITH SOME HAIL.
STILL MONITORING THE WEATHER SITUATION LATER THIS WEEK INTO THE
WEEKEND. MOISTURE WILL BE INCREASING...AND WITH ENOUGH UPSLOPE
FLOW FOR A LONG DURATION...WE WILL INCREASE THE CHANCES FOR
HEAVIER RAINFALL FROM STORMS ALONG THE FOOTHILLS. SLOWER MOVING
STORMS ARE EXPECTED THURSDAY AND FRIDAY...WITH HIGHER AVAILABLE
MOISTURE FRIDAY. SLOW MOVING THUNDERSTORMS THESE
DAYS...ESPECIALLY FRIDAY...COULD LEAD TO 1 TO 2 INCHES IN LESS
THAN AN HOUR IN SOME AREAS IF ENOUGH UPSLOPE KEEPS THEM OVER THE
HIGHER TERRAIN. BUT THERE ARE SOME HINTS OF MODELS WANTING TO TURN
THE WINDS SOUTHWESTERLY THAT WOULD PUSH THEM OFF THE HILLS. IF A
STRONGER AND SLOW MOVING STORM SETS UP OVER THE HIGHER ELEVATION
WHERE SNOW IS...THIS COULD INCREASE THE THREAT FOR RIVER/STREAM
FLOODING DUE TO A COMBINATION OF MELTING SNOW AND RAINFALL.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM...KRIEDERMAN
AVIATION...BARJENBRUCH
HYDROLOGY...BARJENBRUCH/KRIEDERMAN
AREA FORECAST DISCUSSION
NWS DES MOINES IA
332 AM CDT TUE MAY 20 2014
.SHORT TERM /TODAY/...
ISSUED AT 332 AM CDT TUE MAY 20 2014
ISOLATED CENTRAL IA THUNDERSTORM APPROACHING SEVERE LIMITS
DISSIPATED QUICKLY LAST HOUR. RAP SOUNDINGS SEEMED TO REFLECT THE
ENVIRONMENT QUITE WELL WITH POTENTIAL FOR STORMS ROOTED NEAR THE
SURFACE SHORTLY AFTER MIDNIGHT...BUT MLCINH INCREASING QUICKLY AS
BOUNDARY LAYER COOLS FURTHER AND DECOUPLING FINALLY TAKING PLACE.
WITH THIS PROGRESSION DO NOT REALLY EXPECT ANY ADDITIONAL
DEVELOPMENT UNTIL PEAK HEATING OF THE AFTERNOON...WHICH IS THE
PRIMARY FORECAST CONCERN.
SCENARIO FOR TODAY HAS CHANGED LITTLE OVER THE PAST FEW DAYS WITH
SEVERE WEATHER POTENTIAL STILL CONDITIONAL. MODELS ALL DEPICT
SIMILAR THERMODYNAMIC ENVIRONMENT WITH MLCINH ERODING DURING THE
AFTERNOON AND MLCAPES TO AROUND 1500 J/KG. HOWEVER WHILE THE CINH
HAS DIMINISHED SUFFICIENTLY FOR CONVECTION TO FIRE...LIMITING
FACTORS INCLUDE WEAK CONVERGENCE AND THE FACT THAT WARM 1-3KM
TEMPS WILL KEEP PARCELS FROM REALLY ACCELERATING UNTIL REACHING
3KM OR HIGHER. THERE IS A QUESTION WHETHER THE WEAK CONVERGENCE
WILL OVERCOME THIS. LARGE SCALE FORCING MAY HELP LIFT AND
DESTABILIZATION OF 1-3KM LAYER TOWARD 00Z HOWEVER AS CURRENT
DAKOTAS MN JET SEGMENT MOVES EASTWARD. THUS STILL HAVE SCATTERED
THUNDERSTORMS DEVELOPING IN THE EASTERN HIGHWAY 30/I80/HIGHWAY 92
CORRIDORS. MAIN SEVERE THREATS STILL APPEAR TO BE LARGE HAIL OR
WIND. LOW LEVEL SHEAR FAIRLY WEAK WITH HIGHER LCLS. STORM MOTION
WILL BE FAIRLY SLOW TOO BASED ON MEAN WIND AND BUNKERS
MOTION...LIKELY UNDER 25KTS.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 332 AM CDT TUE MAY 20 2014
THE SURFACE TROUGH SERVING AS A FOCUS FOR THUNDERSTORM DEVELOPMENT
THIS AFTERNOON...AS DISCUSSED IN THE SHORT TERM SECTION
ABOVE...WILL MOVE SOUTH OUT OF THE AREA TONIGHT WITH DECREASING
POPS OVERNIGHT. THEREAFTER...THE BOUNDARY WILL REMAIN OVER
MISSOURI WITH A LARGE SURFACE HIGH PRESSURE AREA BUILDING OVER
IOWA AND THE UPPER MIDWEST FOR SEVERAL DAYS. THIS WILL KEEP
TEMPERATURES RELATIVELY COOL TOWARD THURSDAY AND FRIDAY WITH RAIN
CHANCES REMAINING OVER MISSOURI OR POSSIBLY AFFECTING THE FAR
SOUTHERN FRINGE OF IOWA AT TIMES.
MEANWHILE...AT 500 MB A LARGE CUTOFF LOW WILL DEVELOP OVER THE
FAR SOUTHWEST U.S. LATE THIS WEEK AND RESIDE SOMEWHERE AROUND THE
CALIFORNIA/ARIZONA BORDER BY FRIDAY MORNING. THIS WILL SQUEEZE A
500 MB RIDGE DOWNSTREAM ACROSS THE CENTRAL U.S. AND UP TOWARD
IOWA. AS THE CUTOFF LOW SLOWLY MOVES EASTWARD THIS CENTRAL U.S.
RIDGE WILL STEADILY ERODE...ALLOWING THE UPPER MIDWEST SURFACE
RIDGE TO SLIDE EASTWARD WITH A RETURN OF SOUTHEAST SURFACE FLOW
OVER IOWA AND THE OLD FRONTAL BOUNDARY MOVING BACK OVERHEAD. THIS
WILL RESULT IN RAIN CHANCES RETURNING TO THE FORECAST AREA THIS
WEEKEND AND INTO EARLY NEXT WEEK...PERSISTING FOR MULTIPLE DAYS AS
THE 500 MB LOW MOVES INTO THE AREA THROUGH THE END OF THE SEVEN
DAY FORECAST PERIOD. CONSEQUENTLY FROM SATURDAY ONWARD GENERALLY
30 TO 40 POPS ARE CARRIED IN EVERY PERIOD WITH GRADUALLY
INCREASING TEMPERATURES.
&&
.AVIATION...20/06Z
ISSUED AT 1156 PM CDT MON MAY 19 2014
VFR CONDITIONS TO BEGIN THE PERIOD. POTENTIAL FOR LOCALIZED VSBY
REDUCTIONS DUE TO FOG ESPECIALLY VICINITY OF KMCW AND KALO. A FEW
SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE OVERNIGHT ALSO.
GENERALLY VFR THROUGH TUESDAY WITH POTENTIAL FOR A FEW AFTERNOON
TO EARLY EVENING THUNDERSTORMS WITH BEST POTENTIAL NEAR KOTM. A
BOUNDARY WILL SLOWLY SAG THROUGH THE STATE BY TUESDAY MORNING
BRINGING A SWITCH TO NORTH TO NORTHEAST WINDS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
507 AM EDT TUE MAY 20 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 506 AM EDT TUE MAY 20 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A SHORTWAVE TROUGH MOVING
THROUGH NRN WI IN WRLY FLOW BETWEEN A LOW OVER SE SASK AND A RIDGE
OVER THE LOWER MS VALLEY. AT THE SFC...AN OCCLUDED FRONT EXTENDED
FROM THROUGH WRN MN FROM LOW PRES OVER SRN MANITOBA. STRONG
300K-305K ISENTROPIC LIFT NORTH OF AN 850 MB WARM FRONT OVER NRN WI
SUPPORTED SHOWERS ACROSS MOST OF UPPER MI. A FEW TSRA FROM NRN WI
WERE MOVING INTO WRN UPPER MI WHERE MUCAPE VALUES WERE NEAR 500
J/KG.
TODAY...EXPECT THE PCPN TO DEPART FROM WEST TO EAST THIS MORNING AS
THE SHORTWAVE TROUGH AND STRONGER ISENTROPIC LIFT MOVE OUT AND MID
LEVEL DRYING TAKES OVER. THE BEST CHANCE FOR TSRA SHOULD REMAIN OVER
THE SOUTH NEAR THE AXIS OF STRONGER MUCAPE. WITH MAINLY DRY
CONDITIONS DURING THE AFTERNOON...TEMPERATURES SHOULD REBOUND INTO
THE 60S TO NEAR 70...WARMEST NEAR THE WI BORDER.
TONIGHT...AS A SHORTWAVE TROUGH SLIDES TO THE EAST FROM NE NORTH
DAKOTA TO NRN LAKE SUPERIOR MODERATE 700-300 QVECTOR CONV AND UPPER
LEVEL DIV WITH THE LEFT EXIT OF THE 250-300 MB JET WILL SUPPORT A
CHANCE OF SHOWERS THROUGH THE CWA MAINLY AFT 06Z...WITH THE HIGHEST
POPS ACROSS THE NORTH. INCREASING MID LEVEL LAPSE RATES AND FCST
MUCAPE VALUES IN THE 400-800 J/KG RANGE SHOULD ALSO SUPPORT A FEW
TSRA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 303 AM EDT TUE MAY 20 2014
AT 12Z WEDNESDAY THE MAIN 500MB LOW WILL BE SITUATED ACROSS ONTARIO
WITH A SHORTWAVE/TROUGH EXTENDING ACROSS MN. LOOK FOR THIS FEATURE
TO CROSS UPPER MI THROUGH THE DAY. THE SFC LOW OVERHEAD WITH IT/S
OCCLUDED FRONT AT 12Z WILL QUICKLY EXITING E /ACROSS FAR E UPPER MI
AT 18Z/. DESPITE THE EXITING LOW A FEW SHOWERS WILL STILL BE
POSSIBLE WEDNESDAY-WEDNESDAY NIGHT...WHEN HIGH PRESSURE BUILDS IN AT
THE SFC AND ALOFT.
AS FOR SOME OF THE SMALL-SCALE FEATURES OF INTEREST...NW WINDS
SHOULD BECOME GUSTY WEDNESDAY AFTERNOON THROUGH THURSDAY. PW VALUES
STILL LOOK TO FALL TO AROUND 0.5IN /55 PERCENT OF NORMAL/ OVER THE W
HALF OF UPPER MI WEDNESDAY AFTERNOON THROUGH THE END OF THE WORK
WEEK. WILL NEED TO MONITOR THOSE AREAS THAT MAY NOT RECEIVE AS MUCH
RAIN FOR FIRE WX CONCERNS UNTIL THE WINDS DIMINISH THURSDAY EVENING
THROUGH FRIDAY AS THE SFC HIGH EXTENDING FROM S LAKE HURON AND THE N
PLAINS SLIPS DIRECTLY OVERHEAD.
HIGH TEMPERATURES WILL RETURN BACK TO SEASONAL NORMAL VALUES FOR
FRIDAY UNDER A MOSTLY SUNNY SKY...WITH 60S FOR MOST AREAS AND A FEW
POCKETS OF 70 DEGREE READINGS OVER THE INTERIOR W HALF.
THE CENTER OF THE SFC HIGH WILL SLIP JUST TO THE E OF UPPER MI
SATURDAY AFTERNOON. 850MB TEMPS WILL JUMP APPROX 2C FROM AROUND 8C
FRIDAY AFTERNOON TO 11C SATURDAY AS SW WINDS AND INCREASED MOISTURE
MAKE A RETURN TO THE CWA. THE WARMEST DAY LOOKS TO BE SUNDAY AS
850MB TEMPS RISE TO AROUND 15C AT 850MB ON 20KT SW FLOW. UPPER 70S
WILL BE POSSIBLE OVER THE INTERIOR W HALF OF UPPER MI...WHICH MAY
GLIDE TO THE DOWNSLOPE AREAS OF THE N CENTRAL CWA ALONG LAKE
SUPERIOR /ASSUMING LITTLE TO NO LAKE BREEZE POTENTIAL OFF LAKE
SUPERIOR/. ONE THING THAT COULD KNOCK THE TEMPS DOWN A BIT OVER THE
W HALF WOULD BE APPROACHING RAIN SHOWERS /AND ISOLATED TS/ AS THE
ELONGATED SFC LOW STRETCHING ACROSS THE PLAINS AND W ONTARIO NEARS.
THE 500MB LOW OVER CENTRAL CA TODAY WILL SPIN ACROSS THE 4-CORNERS
REGION ON SATURDAY...BEFORE SLOWLY EJECTING NE TO THE CENTRAL PLAINS
BY THE END OF THE DAY MONDAY. THE 500MB RIDGE WILL REMAIN EITHER
JUST W OR OVER THE UPPER GREAT LAKES THROUGH 00Z SUNDAY. THE
POTENTIAL FOR UNSETTLED WEATHER WILL RETURN TO END THE WORK WEEK.
KEPT THE SLIGHT CHANCE OF TS IN THE FCST FOR LATE SUNDAY AFTERNOON
THROUGH MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 132 AM EDT TUE MAY 20 2014
THE INTERACTION BTWN A STRENGTHENING SSW FLOW DRAWING MORE MOIST AIR
INTO THE UPR LKS AND VIGOROUS DYNAMIC FORCING WL RESULT IN WDSPRD
SHRA AND PREDOMINANT MVFR CONDITIONS AT THE TAF SITES THRU SUNRISE.
THE STRENGTHENING SSW FLOW JUST ABV THE NEAR SFC STABLE LYR WL
RESULT IN LLWS AS WELL. DOWNSLOPE NATURE OF THE SE FLOW AT IWD MAY
TEND TO MAINTAIN VFR WX THERE FOR A TIME EARLY IN THE FCST. BEST CHC
FOR IFR AND EVEN LIFR CIGS WL BE AT SAW...WHERE THE LLVL SE FLOW
PRESENTS A SHARPER UPSLOPE COMPONENT. NOT OUT OF THE QUESTION THERE
COULD BE A TS...ESPECIALLY AT IWD...BUT DID NOT INCLUDE A SPECIFIC
MENTION ATTM GIVEN LO CONFIDENCE ON THE OCCURRENCE. WITH THE ARRIVAL
OF DRYING ON TUE AND DAYTIME HEATING/MIXING...EXPECT IMPROVING
CONDITIONS TO VFR IN THE AFTN. THE APRCH OF ANOTHER DISTURBANCE MAY
BRING A FEW -SHRA TO CMX/IWD LATER THIS EVNG. LINGERING SHALLOW
MOIST AIRMASS MAY RESULT IN SOME LO CLDS AT CMX...BUT INCOMING
AIRMASS FM THE NRN PLAINS IS SO DRY PER THE 00Z BISMARCK RAOB THAT
THE PROBABILITY OF LO CLDS IS TOO LO TO MENTION ATTM.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 506 AM EDT TUE MAY 20 2014
SE WINDS OF 15 TO 25 KNOTS OVER THE ERN PORTION OF THE LAKE WILL
DIMINISH THIS AFTERNOON AND REMAIN AT OR BELOW 20 KNOTS THROUGH
SATURDAY AS A MAINLY STABLE MARINE LAYER WILL PREVAIL. WITH THE RAIN
AND INFLUX OF LOW LEVEL MOISTURE INTO THE REGION...SOME FOG MAY
DEVELOP FROM TODAY INTO WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1134 PM CDT Mon May 19 2014
.UPDATE:
Issued at 930 PM CDT Mon May 19 2014
Only minor changes needed to going forecasts, primarily to tweak
latest sky trends. Forecast for tonight will remain dry, but
obviously with the FA on the fringes of the westerlies we will
need to keep an eye out overnight for subtle clues to potential
development. One area of potential concern is any development that
could occur in low level convergence near boundary over se NE,
which has been hinted at by the HRRR over the last few hours. It
this were to occur, some of this activity could clip extreme
northern areas during the predawn hours. The second...and even
more subtle...area is over eastern areas very late tonight as
shortwave brushes area of low level WAA and moisture convergence
leading to an outside chance of elevated development in situ (ie:
sunrise surprise). While both scenarios bear watching, not seeing
clear enough signals in either the latest UA data and/or short
range guidance and forecast soundings to include any mention of
precip.
Truett
&&
.SHORT TERM: (Through Late Tonight)
Issued at 350 PM CDT Mon May 19 2014
Strong pressure gradient between the high over the eastern seaboard
and low pressure over western Kansas is causing strong winds across
the area this afternoon. Should see gusts diminish this evening
after we lose daytime heating, and overall surface winds will also
diminish as the surface low fills in a bit and the high over the
east coast dips south causing the pressure gradient to slacken.
However, all short range models show weak to moderate moisture
convergence over the area on the nose of the low level jet which
will ramp up to 40-50kts overnight. The GFS does spit out a few
spotty hundredths of precip, but it`s the outlier. Have kept below
mention PoPs overnight. Should see temperatures continuing to
moderate with lows pretty much universally in the low to mid 60s
across the area.
Carney
.LONG TERM: (Tuesday through Next Monday)
Issued at 350 PM CDT Mon May 19 2014
(Tuesday - Sunday)
Above average temps will prevail early in this period, then slip
back closer to normal for late week and into next weekend. A
persistent chance for thunderstorms will exist from Wednesday on.
An upper level ridge will build into the Mid-MS Valley by Tuesday in
response to a strong Pacific storm system digging into the
southwestern CONUS. This will lead to a period of above average
temps for our region. In addition, a series of upper level
disturbances will begin to ripple on through along the ridge`s
periphery. At first, moisture will be somewhat limited, the cap too
strong, and there will be the lack of a surface boundary, with the
nearest synoptic front to our north. Pcpn chances Tuesday and
Tuesday night look too low for a mentionable chance but it looks
close for a time Tuesday morning for the STL metro and surrounding
areas and again late on Tuesday night in northern MO and central IL.
By Wednesday, as a cold front drops into northern MO and central IL,
there should be sufficient elements in place to begin the chance for
TSRA and expand this chance to the rest of the forecast area late
Wednesday afternoon or night. The presence of the slowly southward
moving front...and persistent upper level disturbances will maintain
chances for TSRA thru late week and, to some extent, into the
weekend, although it will be important to note that PoPs by this
time will be below climatological values, despite being mentioned.
(Next Monday)
Still a lot of questions left unanswered as we head out into next
week with the fate of the powerful storm system in the Southwest.
The EC wants to push it into the northern High Plains while the GFS
keeps it over OK. The one commonality is that this system pushes
another disturbance, while either bucking the surface front back to
the north or dissolving it altogether, keeping pcpn chances out
until just beyond this period.
Temps push back to above normal with the resultant southerly flow.
TES
&&
.AVIATION: (For the 06z TAFs through 06z Tuesday Night)
Issued at 1134 PM CDT Mon May 19 2014
South winds to persist early this morning with decent low level
jet setting up over central MO, so kept mention of LLWS for KCOU
after 06z. Still not confident the winds aloft will be strong
enough for LLWS over metro area, so kept out mention for now. Then
by mid morning today, winds mix down to surface with gusty south
winds once again before diminishing after sunset. Frontal boundary
to begin sliding south towards forecast area this evening, so will see
winds become westerly at KUIN towards end of forecast period. VFR
conditions to persist.
Specifics for KSTL:
South winds to persist early this morning with decent low level
jet setting up over central MO, but not confident the winds aloft
will be strong enough for LLWS over metro area, so kept out
mention for now. Then by 15z today, winds mix down to
surface with gusty south winds once again before diminishing after
sunset and veering to the southwest. VFR conditions to persist.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
302 AM CDT TUE MAY 20 2014
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
WV IMAGERY THIS MORNING SHOWING POS TILT LONGWAVE TROF EXTENDING
FROM CNTRL CANADA TO THE WEST COAST WITH TWO DISTINCT CLOSED
CIRCULATIONS SEEN...ONE CENTERED OVER S-CNTRL CANADA AND THE OTHER
OF THE NRN CA COASTLINE. SATL PIX ALSO REVEALING MOVEMENT MOVEMENT OF
THIS FEATURE HAS BEEN MINIMAL THE LAST SEVERAL HOURS....BUT MODELS
IN GOOD AGREEMENT WEST COAST CIRCULATION WILL GRADUALLY BECOME CUT
OFF FROM MAIN FLOW BY THE TIME IT REACHES THE SWRN CONUS LATER THIS
WEEK.
MEANWHILE...DISTINCT SFC THERMAL BNDRY WAS SITUATED FROM NRN IA TO S-
CNTRL NEB TO WRN KS WITH LLVL MOISTURE ADV SPREADING NWD THRU OK/KS
AND INTO THE SRN CWA. OUT WEST...SMALL AREA OF ELEVATED CONVECTION
WAS SITUATED WITHIN AREA OF 700MB QG FRONTOGENESIS/MODEST BNDRY LYR
CONVG. LATEST HRRR IS SUGGESTING ACTIVITY WILL BE SHORT LIVED AS
ENVIRONMENT BECOMES MORE STABLE IN THE NEXT COUPLE COUPLE HOURS.
LATEST MODELS CONFIRM GOING FCST IS IN PRETTY GOOD SHAPE ADVERTISING
CONVECTIVE ACTIVITY LATER THIS WEEK...PARTICULARLY OVER WESTERN
SECTIONS OF THE CWA. AS AFOREMENTIONED UPPER LOW BECOMES CUT
OFF...FLOW ALOFT OVER THE CNTRL PLAINS WILL BECOME LESS PROGRESSIVE
AND ALLOW MID LYR FRONTOGENETIC FORCING ORIENTED NW-SE TO REMAIN
INVOF THE WRN CWA. THAT ALONG WITH RELATIVELY STRONG BNDRY LYR THETA-
E CONVG SHOULD ALLOW FOR TSTMS CHANCES BEGINNING LATE WED AFTN ALL
THE WAY INTO LATE THURSDAY NIGHT. AMPLE ENVIRONMENTAL MOISTURE WILL
BE ON TAP...PWS 1.75"/KI 35-40...THUS POTENTIAL FOR GENEROUS
RAINFALL AMOUNTS APPEAR TO BE RELATIVELY HIGH.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
MODELS CONTINUE TO ADVERTISE WRN CIRCULATION WILL BE QUITE SO
MIGRATING EWD THRU THE EXTENDED PDS..ALLOWING FOR CONTINUOUS SLY
LLVL MOIST ADV INTO THE CNTRL PLAINS. WITH INSTABILITY/MOISTURE AXIS
REMAINING INVOF THE CWA...WILL CARRY POPS THRU NEXT WEEKEND AND INTO
EARLY NEXT WEEK. IN ADDITION...COMPOSITE PARAMETERS SUGGEST SVR
THREAT IS MINIMAL AT BEST.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1207 AM CDT TUE MAY 20 2014
WILL CONTINUE TO MONITOR THE RADAR FOR OVERNIGHT CONVECTION. HAVE
HAD A FEW STORMS BUBBLE UP JUST TO THE NORTHEAST OF THE TAFS.
THERE IS A SFC BOUNDARY IN PLACE WITH MOISTURE AND INSTABILITY IN
PLACE AND WEAK LIFT WILL MOVE ACROSS THE REGION OVERNIGHT. THERE
ARE QUITE A BIT OF CIRRUS SPREADING EAST. THE SHORT RANGE MODELS
HAVE LESSENED THE CHANCE OF STRATUS REDEVELOPMENT...SO HAVE MAINLY
MID AND HIGH CLOUDS FOR NOW...HOWEVER WITH MOISTURE AND WEAK FLOW
NEAR THE BOUNDARY...COULD SEE THESE LOW CLOUDS RE-DEVELOP.
TUESDAY...THE FOCUS FOR WEATHER WILL STILL BE IN THE VICINITY OF
THE FRONT AND MAINLY COULD AFFECT KOMA AND KLNK.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE
LONG TERM...DEE
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
100 AM CDT TUE MAY 20 2014
.SYNOPSIS...
ISSUED AT 305 PM CDT MON MAY 19 2014
H5 ANALYSIS FROM THIS MORNING IS INDICATING A BROAD LOW AMPLITUDE
RIDGE ACROSS THE UPPER MISSISSIPPI VALLEY. FURTHER WEST...A STRONG
SHORTWAVE WAS PUSHING ON SHORE ALONG THE WASHINGTON AND OREGON
COASTS. HT FALLS WERE MOST PRONOUNCED OVER WYOMING AND EASTERN MT
WITH 40 TO 50 METER FALLS NOTED. FURTHER SOUTH AND EAST...WEAK HT
FALLS OF 10 TO 30 METERS WERE NOTED FROM WESTERN NEBRASKA INTO
WESTERN SOUTH DAKOTA AND CENTRAL NORTH DAKOTA. AT THE SURFACE...LOW
PRESSURE WAS NOTED OVER NRN SD AND NORTH CENTRAL KS. A FRONTAL
BOUNDARY EXTENDED ACROSS CENTRAL NEBRASKA. EAST OF THIS
FEATURE...WINDS WERE SOUTHERLY WITH NORTHERLY WINDS NOTED WEST OF
THIS FEATURE. A DRYLINE EXTENDED FROM JUST EAST OF IMPERIAL...NNWD
INTO THE NORTHERN NEBRASKA PANHANDLE. DEW POINTS EAST OF THIS
FEATURE WERE IN THE MIDDLE TO UPPER 50S...WHILE WEST OF THIS
FEATURE...DEW POINTS WERE IN THE 40S. RADAR IMAGERY AS OF 2 PM
CDT...SHOWS SOME NICE RETURNS BEGINNING TO DEVELOP INVOF THE I25
CORRIDOR IN EASTERN WYOMING...FROM NORTH OF CHEYENNE TO SOUTHEAST OF
DOUGLAS. OTHER ECHOES WERE NOTED OVER THE NORTHERN NEBRASKA
PANHANDLE INTO SWRN SOUTH DAKOTA. BASED ON SFC OBS...MUCH OF THIS
PCPN ISN/T REACHING THE GROUND ATTM. AS OF 2 PM CDT...UNDER MOSTLY
CLEAR SKIES...TEMPERATURES RANGED FROM 73 AT VALENTINE...TO 85 AT
IMPERIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM CDT MON MAY 19 2014
THUNDERSTORM CHANCES ARE THE MAIN FORECASTING CONCERN FOR TONIGHT
AND TUESDAY. A TANDEM OF SHORTWAVES WILL LIFT INTO THE HIGH PLAINS
OVER THE NEXT 3 TO 6 HOURS. THE FIRST WILL LIFT FROM EASTERN WYOMING
INTO THE NORTHERN NEBRASKA PANHANDLE...THEN NORTHERN NEBRASKA. THE
SECOND WILL LIFT INTO THE SANDHILLS FROM NERN COLORADO. THE FIRST
DISTURBANCE HAS ALREADY LED TO SOME HIGH BASED SHOWERS OVER THE HIGH
PLAINS OF EASTERN WYOMING. AS THIS ACTIVITY MOVES EAST...IT SHOULD
BECOME BETTER ORGANIZED...LIFTING ACROSS NORTH CENTRAL NEBRASKA
THROUGH THE EVENING HOURS. FURTHER SOUTH...THE SECOND SHORTWAVE WILL
LIFT EAST INTO THE WESTERN SANDHILLS THIS EVENING. CAP STRENGTH WILL
REMAIN IN PLACE THROUGH 00Z WHERE IT BEGINS TO ERODE FROM OGALLALA
TO THEDFORD. IN THESE AREAS...AM EXPECTING CONVECTIVE INITIATION
AROUND THE 6 TO 7 PM CDT TIME FRAME THIS EVENING. BULK SHEAR IS IN
THE 35 TO 45 KT RANGE NEAR THE INITIATION POINT...HOWEVER...IT FALLS
OFF TO AROUND 30 KTS EAST OF HIGHWAY 183...SO AM EXPECTING THE MAIN
SEVERE THREAT TO BE CONFINED TO THE SANDHILLS NORTH OF INTERSTATE 80
AND WEST OF HIGHWAY 183. ISOLATED COVERAGE IS EXPECTED AND IS
SUPPORTED BY THE LATEST 4KM WRF AND HRRR SOLNS WHICH DEVELOP
STRONG...BUT ISOLATED STORMS ACROSS THE SANDHILLS THIS EVENING. AS
FOR SEVERE TYPES...CONTINUED THINKING IS LARGE HAIL FOR THE MAIN
SEVERE TYPE AS LOW LEVEL HELICITIES ARE NOT OVERLY IMPRESSIVE THIS
EVENING. WET BULB ZEROS AROUND 8000 FT AGL FAVOR LARGE HAIL AS WELL.
WE MAY SEE SOME GUSTY WINDS INVOF ANY STORMS...HOWEVER...SINCE
LINEAR SEGMENTS ARE NOT EXPECTED...WIDESPREAD SEVERE WINDS ARE NOT
ANTICIPATED ATTM. CONVECTIVE ACTIVITY IS EXPECTED TO MOVE EAST OF
THE FORECAST AREA BY LATE EVENING...HOWEVER...SOME LIGHT RAIN
SHOWERS WILL CONTINUE TO BE A THREAT IN THE NORTHWESTERN CWA WHERE
MID LEVEL PERSISTS INTO THE OVERNIGHT. FOR TOMORROW...TEMPERATURES
WILL COOL SLIGHTLY AS A FRONTAL BOUNDARY IS FORCED SOUTH INTO
KANSAS. THE MAIN THREAT FOR PCPN WILL FOLLOW. WITH THE EXCEPTION OF
THE WESTERN FORECAST AREA...MAINLY DRY CONDS WILL REMAIN IN PLACE.
HIGHS TUESDAY WILL RANGE FROM AROUND 70 IN THE NORTHWEST...TO NEAR
80 IN THE SOUTHEAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM CDT MON MAY 19 2014
FOR TUESDAY NIGHT...THE 12Z NAM12 AND GFS40 ARE SIMILAR WITH THE
LOCATION OF THE QUASI-STATIONARY FRONT ACROSS NORTHEAST TO SOUTHWEST
KANSAS WITH THE 0-2KM THETA-E RIDGE ALONG THE KANSAS-NEBRASKA
BORDER. THE GREATEST INSTABILITY IS FROM SOUTHEAST NEBRASKA TO NORTH
CENTRAL KANSAS. THERE IS SOME MARGINAL INSTABILITY EXTENDING INTO
THE WESTERN NEBRASKA SANDHILLS AND THE PANHANDLE AND THUNDERSTORMS
ARE POSSIBLE TUESDAY EVENING. THE CONVECTIVE POTENTIAL ENERGY IS
LESS THAN 1000J/KG...SO SEVERE THUNDERSTORMS ARE UNLIKELY.
BY WEDNESDAY AFTERNOON...A FINGER OF THE THETA-E RIDGE EXTENDS
NORTHWESTWARD INTO THE SOUTHERN NEBRASKA PANHANDLE ALONG AN INVERTED
SURFACE TROUGH. WITH SURFACE-BASED CONVECTIVE POTENTIAL ENERGY
(CAPE) OF 2000J/KG WEDNESDAY EVENING AND 0-6KM BULK SHEAR OF
40-50KT...SOME STRONG THUNDERSTORMS SHOULD DEVELOP IN SOUTHWEST
NEBRASKA...POSSIBLY COMING ACROSS INTO THE WESTERN SANDHILLS. LATE
WEDNESDAY NIGHT...THE SURFACE BASED LIFTED INDICES SPREAD INTO
CENTRAL AND NORTH CENTRAL NEBRASKA...SO THERE IS A CHANCE OF
THUNDERSTORMS THERE AFTER 06Z
A SIMILAR SITUATION EXISTS FOR THURSDAY AFTERNOON AND FRIDAY
AFTERNOON. WITH THE FORECAST LOCATIONS OF THE MAXIMUM CAPE NEAR THE
NEBRASKA-KANSAS AND THE NEBRASKA-COLORADO BORDERS...THE HIGHEST
PROBABILITY OF STRONG THUNDERSTORMS WILL BE SOUTH OF INTERSTATE
HIGHWAY 80.
FOR SATURDAY AND SUNDAY...THE FRONT STARTS WASHING OUT. STILL WARM
ADVECTION OVER THE HIGH PLAINS BOUNDARY WILL BRING CONTINUE TO BRING
THE POSSIBILITY OF THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. THE
CAPES WILL NOT BE AS HIGH...THOUGH THE HIGHER CAPES WILL COVER A
LARGER PART OF CENTRAL AND WESTERN NEBRASKA. THE 0-6KM BULK SHEAR IS
VERY WEAK...ONLY ABOUT 20KT OR LOWER...SO HEAVY RAIN WOULD BE THE
PRIMARY THREAT. BY SUNDAY...THE MOST FAVORABLE INSTABILITY WILL
SHIFT INTO EASTERN NEBRASKA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 100 AM CDT TUE MAY 20 2014
A FEW SHOWERS ARE LIFTING NORTHEAST ACROSS NW NEB. THEY ARE NEARING
KVTN OVER THE NEXT FEW HOURS...ALTHOUGH LOW CONFIDENCE AND WILL KEEP
OUT OF KVTN TAF AT THIS TIME. OTHERWISE LIGHT NORTHERLY WINDS
THROUGH MID MORNING. THEN NORTHERLY WINDS SHOULD INCREASE TO 10 TO
15 KTS FOR THE AFTERNOON. WILL HAVE TO MONITOR FOR ISOLATED
THUNDERSTORMS TO DEVELOP TOMORROW EVENING ACROSS WESTERN NEBRASKA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...SPRINGER
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
128 AM CDT TUE MAY 20 2014
.UPDATE...
ISSUED AT 128 AM CDT TUE MAY 20 2014
MID LEVEL LOW/SHORT WAVE TROUGH CONTINUES TO SPIN ACROSS SOUTHERN
SASKATCHEWAN. AS THIS FEATURE PROGRESSES SLOWLY EAST...WRAP AROUND
MOISTURE IN THE FORM OF LOW CLOUDS PUSHING SOUTH FROM CANADA
ACROSS THE NORTHERN PLAINS REGION. ADJUSTED SKY TO MATCH LATEST
SATELLITE AND FUTURE PLACEMENT DEPICTED BY THE NAM/RAP.
BASE OF THE TROUGH SWINGS INTO NORTHWEST NORTH DAKOTA 10Z-
12Z...THEN ACROSS MY NORTHERN COUNTIES TUESDAY MORNING AND
AFTERNOON. CHANCE OF SHOWERS AND CLOUD COVER WILL ACCOMPANY THIS
FEATURE ACROSS THE NORTH. ADJUSTED POPS UP A BIT...AND LOWERED
DAYTIME HIGHS ACROSS THE NORTH TO ACCOUNT FOR THE HIGH CLOUD COVER
THROUGH MUCH OF THE DAYLIGHT HOURS.
UPDATE ISSUED AT 820 PM CDT MON MAY 19 2014
AREAS OF LIGHT SHOWERS AND ISOLATED THUNDERSHOWERS CONTINUE THIS
EVENING ACROSS WESTERN AND PORTIONS OF WEST CENTRAL NORTH DAKOTA.
WATER VAPOR IMAGERY CLEARLY SHOWS AN UPPER LOW SPINNING OVER FAR
SOUTHEAST ALBERTA...CONTINUING TO GENERATE AND PINWHEEL AREAS OF
SHOWERS AND ISOLATED THUNDERSHOWERS INTO NORTHEAST MONTANA. AT THE
SURFACE A SECONDARY COLD FRONT WAS LOCATED FROM THE TURTLE
MOUNTAINS BACK INTO GARRISON AND WEST TO SIDNEY. THE SHOWERS AND
THUNDERSTORMS HAVE BEEN MOST CONCENTRATED ALONG THIS LOW LEVEL
CONVERGENCE REGION...AND WILL CONTINUE TO RIDE AND HOVER AROUND
THIS BOUNDARY THROUGH THE EVENING HOURS PER LATEST HRRR. THE HRRR
MAINTAINS A STEADY STATE FLOW WITH THESE SHOWERS THROUGH 09Z
TUESDAY. LATEST SPC MESOSCALE ANALYSIS SUPPORTS MOST UNSTABLE CAPE
VALUES OF AROUND 500 J/KG WITH WEAK SHEAR IN THE WEST. THE BEST
CAPE AND SHEAR STILL RESIDES IN THE JAMES RIVER VALLEY AND WILL
MONITOR THINGS CLOSELY AS THE UPSTREAM PRECIPITATION EDGES CLOSER
INTO THIS AREA.
UPDATE ISSUED AT 530 PM CDT MON MAY 19 2014
LATEST LOCAL/REGIONAL RADAR CONTINUES TO SHOW SCATTERED
THUNDERSTORMS IN NORTHWEST NORTH DAKOTA. RECENT SPOTTER REPORTS
HAVE BEEN CONSISTENT WITH PEA SIZED HAIL AND HEAVY DOWNPOURS WITH
CELLS MOVING ACROSS MCKENZIE COUNTY AND INTO THEODORE ROOSEVELT
PARK NORTH. OUR CURRENT SPECIAL WEATHER STATEMENT HANDLES THIS
AREA WELL AND WILL CONTINUE. CONCERN FOR THE NEXT COUPLE OF HOURS
IS THE SECONDARY AREA OF THUNDERSTORMS JUST READY TO APPROACH
SCOBEY MONTANA. REPORTS OF NICKEL SIZED HAIL WEST OF SCOBEY. THE
LATEST HRRR MAINTAINS REFLECTIVITY INTENSITY AS THIS AREA CROSSES
OUR NORTHWEST BORDER BETWEEN 00Z AND 03Z. IN ADDITION...ISOLATED
THUNDERSTORMS APPROACHING BAKER MONTANA WILL ALSO BE WATCHED THIS
EVENING AS THEY MOVE INTO THE SOUTHWEST. BOWMAN RADAR INDICATIVE
OF ISOLATED SHOWERS WITH POSSIBLE THUNDERSTORM DEVELOPMENT
SHORTLY. LASTLY...WILL WATCH FOR THE SOUTHERN JAMES RIVER VALLEY
FOR THUNDERSTORM DEVELOPMENT. SOME INDICATION PER RAP AND NAM THAT
WE COULD SEE SOMETHING THIS EVENING. ALL ACTIVITY IS FORECAST TO
GRADUALLY WEAKEN AND WANE BY 06Z TUESDAY. MAIN UPDATE WAS TO KEEP
SCATTERED THUNDERSTORMS GOING INTO THE MID EVENING HOURS NORTHWEST
AND KEEP SOME MENTION OF THUNDERSTORMS IN THE SOUTHWEST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 300 PM CDT MON MAY 19 2014
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD IS CONVECTIVE
TRENDS/COVERAGE/INTENSITY THROUGH THIS EVENING.
THE LATEST RUNS OF THE HRRR/WRF/RAP ALL INDICATING SHOWERS AND
STORMS TO DEVELOP OR ADVECT INTO PARTS OF THE FORECAST AREA THIS
AFTERNOON. ONE PRIMARY AREA WILL LIKELY BE THE NORTHWEST...WITH
CURRENT STORMS ONGOING IN NORTHEAST MONTANA...ADDED BY AN UPPER
LOW IN THE VICINITY. THE PRIMARY THREAT AREA FOR STRONG TO NEAR SEVERE
STORMS STILL APPEARS TO BE IN THE JAMES RIVER VALLEY AND...WHERE
THE MOST FAVORABLE DEEP LAYER SHEAR...MOISTURE...AND MID-LEVEL
LAPSE RATES ARE LOCATED. THIS AREA REMAINS OUTLOOKED IN THE 5
PERCENT RISK AREA FOR HAIL. WILL MAINTAIN CHANCE POPS IN THE NORTH
AND THROUGH THE JAMES RIVER VALLEY...WITH SLIGHT CHANCE POPS DOWN
TO NEAR TO INTERSTATE 94 CORRIDOR.
SHOWERS AND ISOLATED THUNDERSTORMS WILL DIMINISH THIS EVENING. A SECONDARY
COLD FRONT WILL DROP SOUTH INTO THE STATE OVERNIGHT...ACCOMPANIED BY
STRATUS. HOWEVER...ADDITIONAL RAIN WILL LIKELY STAY NORTH OF THE BORDER.
ON TUESDAY...EXPECT SOMEWHAT COOLER TEMPERATURES WITH A FEW SHOWERS
POSSIBLE ACROSS THE FAR NORTH DURING THE AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CDT MON MAY 19 2014
TUESDAY NIGHT AND WEDNESDAY...SURFACE HIGH PRESSURE MOVES INTO THE
STATE ALONG WITH THE EXITING OF AN UPPER LEVEL SHORTWAVE. COOL AND
DRY WITH TUESDAY NIGHT LOWS FROM THE UPPER 30S TO LOWER 40S. MOSTLY
SUNNY ON WEDNESDAY WITH HIGHS IN THE 60S.
WEDNESDAY NIGHT AND THURSDAY...THE SURFACE HIGH IS CENTERED EAST OF
THE FORECAST AREA WITH SOUTHERLY SURFACE FLOW AND INCREASING
DEWPOINTS. THE MODELS ARE IN AGREEMENT WITH SOME SHORTWAVE ENERGY
MOVING NORTH/NORTHEASTWARD FROM A LONGWAVE TROUGH OVER THE ROCKIES.
CHANCES OF THUNDERSTORMS IN SOUTHWESTERN NORTH DAKOTA WEDNESDAY
NIGHT AND OVER THE WESTERN HALF OF THE STATE ON THURSDAY. A BIT
WARMER THURSDAY WITH HIGHS 70-75.
THURSDAY NIGHT THROUGH MONDAY THE MODELS ARE IN FAIR AGREEMENT OVER
THE WESTERN AND CENTRAL US WITH AN UPPER LEVEL LOW CUTTING OFF FROM
THE LONGWAVE TROUGH AND REMAINING OVER THE 4-CORNERS AREA THROUGH
SUNDAY. THE MODELS BEGIN TO DIVERGE ON MONDAY WITH THE EUROPEAN
MODEL LIFTING THE CUTOFF LOW NORTHEASTWARD INTO THE CENTRAL
PLAINS...AND THE GFS MOVING THE CUTOFF LOW EASTWARD INTO THE
SOUTHERN PLAINS. THUS HAVE SMALL CHANCES OF THUNDERSTORMS THURSDAY
NIGHT THROUGH FRIDAY NIGHT...WITH INCREASING CHANCES SATURDAY.
CHANCES OF SHOWERS AND THUNDERSTORMS A BIT LOWER SUNDAY THROUGH
MONDAY WITH MORE UNCERTAINTY.
THE GOOD NEWS IS THAT TEMPERATURES SHOULD BE SEASONABLE TO SLIGHTLY
ABOVE AVERAGE WITH HIGHS IN THE 75-80 DEGREE RANGE FOR THE MEMORIAL
DAY WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 128 AM CDT TUE MAY 20 2014
MVFR TO IFR CIGS CONTINUE TO PUSH SOUTH FROM SOUTHERN CANADA INTO
NORTH DAKOTA...AND WILL IMPACT KMOT AND KISN THROUGH
08Z AND ON...EVENTUALLY KBIS-KDIK-KJMS BY 10Z-12Z. LOW CIGS
EXPECTED TO SCATTER OUT TO BKN LOW VFR FOR SOUTHERN TERMINALS OF
KDIK-KBIS- KJMS BY MID MORNING TUESDAY...REMAINING MVFR-IFR FOR
KISN AND KMOT THROUGH 18Z. -SHRA POSSIBLE FOR KISN-KMOT TUESDAY
MORNING/AFTERNOON...ALTHOUGH LITTLE IMPACTS TO AVIATION CURRENTLY
FORECAST. VFR ALL TERMINALS TUESDAY EVENING 00Z-06Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
344 AM EDT TUE MAY 20 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA SLIDES SOUTH THROUGH THE WEEK AS A BACK
DOOR COLD FRONT SLOWLY MOVES SOUTH THROUGH THE REGION THURSDAY AND
FRIDAY. HIGH PRESSURE RETURNS FOR THE THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM...TODAY...AT THE SFC...THE CENTER OF HIGH PRESSURE WILL
REMAIN JUST OFF THE CAROLINA COAST...COVERING THE SOUTHEAST REGION.
AT H5...RIDGE AXIS WILL REMAIN ACROSS THE CENTRAL CONUS AS A TROUGH
REMAINS OVER THE WESTERN ATLANTIC. THE MID LEVEL PATTERN WILL RESULT
IN MID AND UPPER NORTHWEST FLOW. NEAR TERM MODELS INDICATE THAT A
WEAK S/W IS EXPECTED TO RIPPLE ACROSS THE SOUTHERN APPALACHIANS
BETWEEN 21Z-0Z. FORECAST SOUNDINGS INDICATE THAT A WEAK H85
SUBSIDENCE INVERSION WILL CAP THE ENVIRONMENT ACROSS THE FOOTHILLS
AND PIEDMONT. HOWEVER...THE INVERSION AND INHIBITION ACROSS THE MTNS
IS WEAKER. CAPE OVER THE MTNS IS FORECAST TO RANGE BETWEEN 500-1000
J/KG. IN ADDITION...CAMS INDICATE THAT A FEW SHRA/TSRA ARE POSSIBLE
DURING THE HEAT OF THE AFTERNOON ACROSS THE MTNS AND ADJACENT
FOOTHILLS. I BELIEVE THAT THE CAM COVERAGE IS A LITTLE OVERDONE. I
WILL FORECAST SCHC POPS ACROSS THE RIDGES...KEEPING THE VALLEYS AND
FOOTHILLS DRY. HIGH TEMPERATURES ARE FORECAST TO RANGE FROM THE
UPPER 70S WITHIN THE VALLEYS TO LOW 80S EAST.
TONIGHT...CONDITIONS WILL CONTINUE TO FEATURE SFC HIGH PRESSURE NEAR
THE COAST WITH A H5 RIDGE CENTERED OVER THE SOUTHERN MISSISSIPPI
RIVER VALLEY. CONDITIONS ACROSS THE CWA WILL REMAIN DRY WITH LIGHT
SOUTHWEST LLVL FLOW. LOW TEMPERATURES ARE FORECAST TO RANGE FROM THE
MID 50S WITHIN THE MTNS VALLEYS TO LOW 60S ACROSS THE FOOTHILLS AND
PIEDMONT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 215 AM TUE...NWLY FLOW ALOFT DEVELOPS ACROSS THE AREA AND
REMAINS THRU THE SHORT RANGE...AS THE REGION REMAINS BETWEEN AN
UPPER LOW MOVING FROM THE GREAT LAKES TO THE NEW ENGLAND COAST AND
AN ANTICYCLONE MOVING EAST ACROSS THE GULF COAST. A SERIES OF SHORT
WAVES WILL MOVE THRU THE LOW AND ACROSS THE AREA DURING THE PERIOD.
AT THE SFC...A LEE TROF DEVELOPS WED AHEAD OF A BACK DOOR COLD FRONT
MOVING TOWARD THE AREA FROM THE NORTH. THE BACK DOOR COLD FRONT
MOVES INTO THE AREA THU. ALL THESE FEATURES WILL PROVIDE THE FOCUS
FOR CONVECTION DURING THE PERIOD. HOWEVER...STRONG LOW LEVEL WARM
NOSE IN PLACE WED WILL HELP KEEP CONVECTION LIMITED TO ISOLATED
COVERAGE IN THE COUNTIES ALONG THE TN BORDER. THE WARM NOSE ERODES
THU AS THE FRONT MOVES IN. STILL...BEST PRECIP CHC WILL BE ACROSS
THE NC MTNS WHERE LOW LEVEL MOISTURE IS HIGHEST AND LOW LEVEL FLOW
WILL BE CONVERGENT. OUTSIDE OF THE MTNS...ONLY ISOLATED COVERAGE IS
EXPECTED...WITH DIURNAL TIMING. THAT SAID...INSTABILITY AND SHEAR
COULD BE HIGH ENUF FOR A FEW SEVERE STORMS. HIGHS AROUND 15 DEGREES
ABOVE NORMAL WED RISE TO 15 TO 20 DEGREES ABOVE NORMAL THU. LOWS
WILL BE 15 TO 20 DEGREES ABOVE NORMAL WED NITE AND THU.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM TUE...NWLY FLOW ALOFT CONTINUES EARLY IN THE MEDIUM
RANGE AS THE AREA REMAINS BETWEEN THE UPPER LOW OFF THE NEW ENGLAND
COAST AND THE DEVELOPING RIDGE OVER THE CENTRAL CONUS. THE RIDGE
SLIDES OVER THE ERN CONUS BY THE END OF THE PERIOD. AT THE SFC...THE
BACK DOOR COLD FRONT REMAINS STALLED ACROSS THE AREA FRI. THE FRONT
MOVES SOUTH OF THE AREA SAT AS HIGH PRESSURE BUILDS IN FROM THE
NORTH. THE HIGH PRESSURE CENTER SLIDES OFF SHORE SUN AND MON.
ISOLATED DIURNAL CONVECTION DEVELOPS IN THE LINGERING UNSTABLE ATMOS
FRI...WITH DRY FCST FOR SATURDAY AS THE DRIER HIGH PRESSURE BUILDS
IN. SLY FLOW DEVELOPS SUN WITH BEST MOISTURE AND INSTABILITY OVER
THE UPPER SAV RIVER VALLEY INTO THE SWRN MTNS. BETTER CHC OF
CONVECTION ON MON AS THE CONTINUED SLY FLOW BRINGS MOISTURE AND
INSTABILITY ACROSS THE CWFA. HIGHS REMAIN NEARLY STEADY AROUND 5
DEGREES ABOVE NORMAL THRU THE PERIOD. LOWS A LITTLE BELOW NORMAL FRI
AND SAT NITES...RISE A FEW DEGREES ABOVE NORMAL FOR THE END OF THE
PERIOD.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
AT KCLT...VFR VIS AND CEILINGS THROUGH THE 6Z TAF PERIOD. AT
530Z...LATEST IR SATELLITE IMAGES INDICATED THAT THE TERMINAL
REMAINS ON THE EASTERN EDGE OF A PATCH OF MTN WAVE CIRRUS.
HOWEVER...CLOUD TOP TEMPERATURES HAVE WARMED RAPIDLY OVER THE PAST
HALF HOUR. BASED ON THE SATELLITE TRENDS...THE BKN CIRRUS SHOULD
DISSIPATE BY SUNRISE. FORECAST SOUNDINGS INDICATE THAT SCT CU SHOULD
DEVELOP AROUND 060 KFT BY LATE MORNING. WINDS ARE FORECAST TO RANGE
FROM 170-220 DEGREES WITH SPEEDS NEAR 10 KTS DURING THE DAYLIGHT
HOURS.
ELSEWHERE...THE 0Z NAM12 AND 3Z HRRR CONDENSATION PRESSURE DEFICITS
INDICATE THAT MVFR FOG MAY DEVELOP AT KAVL AND KAND DURING THE PRE
DAWN HOURS. ELSEWHERE...CONDITIONS WILL REMAIN VFR THROUGH THE 6Z
TAFS. SOUTHWEST WINDS WILL INCREASE WITH MIXING THROUGH MID
DAY...RANGING FROM 10 TO 15 KTS. FORECAST SOUNDINGS INDICATE THAT
SCT CU SHOULD DEVELOP AROUND 050-060 KFT BY LATE MORNING. CU WILL
GRADUALLY DISSIPATE AROUND SUNSET.
OUTLOOK...DRY RIDGING WILL CONTINUE THROUGH MID WEEK. A BACKDOOR
COLD FRONT MAY DROP ACROSS THE AREA LATER IN THE WEEK...PROVIDING A
FOCUS FOR SCATTERED TSRA.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-07Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND MED 79% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...NED
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
146 AM EDT TUE MAY 20 2014
.SYNOPSIS...
HIGH PRESSURE IS EXPECTED TO BUILD INTO THE REGION FROM THE WEST
THROUGH MID WEEK BRINGING MUCH WARMER TEMPERATURES. A BACK DOOR
COLD FRONT SLOWLY MOVES THROUGH THE REGION THURSDAY AND FRIDAY WITH
LOW RAIN CHANCES AND COOLER TEMPERATURES BY THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 140 AM...LATEST IR SATELLITE IMAGES INDICATED THAT THE
TERMINAL REMAINS ON THE EASTERN EDGE OF A PATCH OF MTN WAVE
CIRRUS. HOWEVER...CLOUD TOP TEMPERATURES HAVE WARMED RAPIDLY OVER
THE PAST HALF HOUR. BASED ON THE SATELLITE TRENDS...THE BKN CIRRUS
SHOULD DISSIPATE BY SUNRISE. FOR THE UPDATE...I WILL ADJUST SKY
AND T/TD THROUGH THE REST OF TONIGHT.
AS OF 1030 PM...THE FCST LOOKS ON TRACK. POPULATED THE OBS GRIDS
INTO THE TEMP AND DWPT GRIDS...AS SOME SITES HAVE FALLEN MORE
QUICKLY THAN FCST. OTHERWISE...NO CHANGES NEEDED.
AS OF 745 PM...FOR THE 2330 UTC UPDATE...ONLY MADE MINOR TWEAKS TO
THE WIND/SKY GRIDS TO BLEND WITH OBS AND LATEST GUIDANCE FOR THE 00Z
TAFS. OTHERWISE...FCST IS ON TRACK.
FOR THE REMAINDER OF THE AFTERNOON...FAIR WEATHER CU SHOULD CONTINUE
ACROSS MOST OF THE FCST AREA. WILL NOT RULE OUT A FEW SHOWERS ALONG
THE RIDGETOPS UNTIL AFTER PEAK HEATING OCCURS...SO THE ISOLATED
SHOWERS WERE KEPT OVER THE MTNS. OTHERWISE...FCST LOOKS LIKE IT IS
IN GOOD SHAPE.
OVER THE NEXT 24 HOURS...THE PATTERN WILL ONLY BE SLOWLY PROGRESSIVE
WITH THE AXIS OF AN UPPER TROF MOVING FARTHER OFFSHORE AND THE AXIS
OF AN UPSTREAM RIDGE BEGINNING IN THE PLAINS/UPPER MS VALLEY REGION
THEN FALLING OVER INTO THE TN/OH VALLEY REGION. THIS WILL KEEP A NW
FLOW ALOFT THROUGH TUESDAY. ONE FEATURE OF NOTE IS A SHORT WAVE
CARRIED BY THE MODELS OVERHEAD EARLY TUESDAY MORNING. THIS WAVE WILL
NOT HAVE MUCH TO WORK WITH AND IS EXPECTED TO ONLY BRING A PATCH OF
MID/HIGH CLOUDS...BUT THIS SHOULD ACT TO KEEP THE FOG IN CHECK
AROUND SUNRISE ON TUESDAY. AFTER SUNRISE...A SURFACE HIGH WILL
SLOWLY MIGRATE OFF TO THE SOUTHEAST AND OFF THE COAST...ALLOWING FOR
SOME WEAK RETURN OF LOW LEVEL MOISTURE AND WARM ADVECTION. THIS
SHOULD ALLOW HIGH TEMPS TO CLIMB ABOUT TWO CATEGORIES HIGHER THAN
TODAY. THE MOISTURE INCREASE SHOULD HELP TO FUEL A BIT MORE SHOWER
ACTIVITY OVER THE MTNS IN THE AFTERNOON...BUT POP WAS STILL KEPT IN
THE SLIGHT CHANCE RANGE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 2 PM EDT MON...MODEL CONSENSUS IS THAT AN UPPER HIGH WILL
BUILD OVER THE LOWER MISSISSIPPI VALLEY BY MIDWEEK WITH HEIGHTS
INCREASING ALSO OVER THE SE STATES. THE HIGH IS FORECAST TO MOVE
SLOWLY EASTWARD THROUGH THU...BUT THE WESTERN CAROLINAS AND NE GA
WILL REMAIN TO THE EAST OF THE HIGH CENTER MAINTAINING DEEP LAYER NW
FLOW OVER THE AREA. AT THE SAME TIME...AN UPPER LOW NEAR JAMES BAY
IS FORECAST TO MOVE SE INTO NORTHERN NEW ENGLAND. THIS WILL BE
ENOUGH TO DRIVE A SURFACE COLD FRONT SE WHICH WILL REACH THE AREA
LATE THU. IN THE MEAN TIME....SURFACE HIGH PRESSURE WILL REMAIN OVER
THE SE STATES THROUGH WED...AND WITH THE WARMING TEMPS ALOFT
CONVECTION SHOULD BE EFFECTIVELY CAPPED. ON THU...WITH THE APPROACH
OF THE COLD FRONT SOME CONVECTION IS POSSIBLE OVER THE MOUNTAINS AND
NORTHERN PIEDMONT AREAS BY LATE IN THE DAY AS THE MID LEVEL CAP IS
SLOWLY ERODED. HENCE...WILL MAINTAIN THE IDEA OF WIDELY SCATTERED/
SCATTERED POPS FOR THU AFTERNOON OVER THE MOUNTAINS/NORTHERN
PIEDMONT. OTHERWISE...WILL ADVERTISE A DRY FORECAST. TEMPS WILL BE
ON THE INCREASE EACH DAY...POSSIBLY TOUCHING 90 ON WED AND EXCEEDING
90 ON THU SOME AREAS IN THE LOWER PIEDMONT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 210 PM MONDAY...THE MEDIUM RANGE FORECAST BEGINS THURSDAY
EVENING WITH HIGH PRESSURE CENTERED OVER THE CENTRAL GULF COAST AND
A BACK DOOR COLD FRONT DROPPING SOUTH ACROSS THE MID ATLANTIC
STATES. LOW LEVEL WIND FLOW WILL BE FROM THE NW THURSDAY NIGHT AND
THEN BECOMING N TO NE TO THE NORTH OF THE SLOWLY MOVING COLD FRONT.
BOTH THE GFS AND ECMWF HAVE AROUND 2000 CAPES AT 00Z FRIDAY SOUTH OF
CLT AND NEAR FONTANA LAKE WITH CLOSE TO 1500 CAPE MID WAY BETWEEN.
THIS RAPIDLY DIMINISHES THURSDAY NIGHT AS THE FRONT MOVES SLOWLY
SOUTH ACROSS THE AREA. CONVECTION ALONG THE FRONT SHOULD BE ISOLATED
TO WIDELY SCATTERED BUT MAINLY OVER THE MTNS. A DISSIPATING MCS
MOVING WITH THE NW FLOW MAY REACH THE NC MTNS THURSDAY EVENING
BEFORE DISSOLVING IN THE DRIER MORE STABLE AIR. AS SURFACE HIGH
PRESSURE DROPS SSE FROM THE CHICAGO AREA FROM THURSDAY NIGHT INTO
THE START OF THE WEEKEND...LOW LEVEL WIND FLOW WILL BE LIGHT FROM
THE N AND NE THEN BECOME LIGHT AND VARIABLE THROUGH THE WEEKEND. A
DRY AND PLEASANT WEEKEND IS NOW IN THE FORECAST. THE UPPER TROUGH
MOVES EAST AND OFF THE COAST SUNDAY NIGHT INTO MONDAY AS AN UPPER
RIDGE BUILDS IN FROM THE GULF STATES. WIND FLOW ON THE GFS AT 925MB
MONDAY AFTERNOON IS FROM THE SW AND CONVERGENT TO THE UPPER SAVANNAH
VALLEY AND AM PLACING SLIGHT POPS IN THAT AREA WITH BRIEF LOW CHANCE
NEAR THE HIGHLANDS AND CASHIERS NC AREA. HIGHS NEAR OR JUST ABOVE
NORMAL THROUGH THE WEEKEND AND BECOMING WARMER MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AT KCLT...VFR VIS AND CEILINGS THROUGH THE 6Z TAF PERIOD. AT
530Z...LATEST IR SATELLITE IMAGES INDICATED THAT THE TERMINAL
REMAINS ON THE EASTERN EDGE OF A PATCH OF MTN WAVE CIRRUS.
HOWEVER...CLOUD TOP TEMPERATURES HAVE WARMED RAPIDLY OVER THE PAST
HALF HOUR. BASED ON THE SATELLITE TRENDS...THE BKN CIRRUS SHOULD
DISSIPATE BY SUNRISE. FORECAST SOUNDINGS INDICATE THAT SCT CU SHOULD
DEVELOP AROUND 060 KFT BY LATE MORNING. WINDS ARE FORECAST TO RANGE
FROM 170-220 DEGREES WITH SPEEDS NEAR 10 KTS DURING THE DAYLIGHT
HOURS.
ELSEWHERE...THE 0Z NAM12 AND 3Z HRRR CONDENSATION PRESSURE DEFICITS
INDICATE THAT MVFR FOG MAY DEVELOP AT KAVL AND KAND DURING THE PRE
DAWN HOURS. ELSEWHERE...CONDITIONS WILL REMAIN VFR THROUGH THE 6Z
TAFS. SOUTHWEST WINDS WILL INCREASE WITH MIXING THROUGH MID
DAY...RANGING FROM 10 TO 15 KTS. FORECAST SOUNDINGS INDICATE THAT
SCT CU SHOULD DEVELOP AROUND 050-060 KFT BY LATE MORNING. CU WILL
GRADUALLY DISSIPATE AROUND SUNSET.
OUTLOOK...DRY RIDGING WILL CONTINUE THROUGH MID WEEK. A BACKDOOR
COLD FRONT MAY DROP ACROSS THE AREA LATER IN THE WEEK...PROVIDING A
FOCUS FOR SCATTERED TSRA.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 95% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...NED
SHORT TERM...LG
LONG TERM...DEO
AVIATION...NED
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.
&&
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
PCPN CHANCES EARLY IN THE PERIOD ARE THE MAIN ISSUE IN THE SHORT
RANGE. FOR TNT FRONTAL BOUNDARY WILL EDGE SLOWLY ACROSS NORTHEAST SD
AND INTO WESTERN MINNESOTA. WITHIN THE FRONTAL BOUNDARY A NARROW
AREA OF MIXED LAYER CAPES UP TO 1500 J/KG WILL EXIST. MEANWHILE
DEEP LAYER SHEAR IS EXPECTED TO INCREASE TNT AS S/W MOVES ACROSS
STATE. WITH INSTABILITY AXIS SO NARROW SUSPECT THAT IF ANY STORMS
GET GOING OVER THE EAST THEY WILL BE DRIVEN MAINLY BY WEAK FRONTAL
CONVERGENCE AND DIABATIC HEATING NEAR FRONT. THIS ACTIVITY SHOULD
BE DONE BY SUNSET AND LIKELY WILL BE ISOLATED IN COVERAGE AT BEST.
FOR THE WESTERN CWA AM INCLINED TO THINK THAT THE INCREASING
WINDS ALOFT WITH S/W IN COMBINATION WITH SOME WEAK MIXED LAYER
CAPE COULD RESULT IN AN ISOLATED SHOWER/STORM BEFORE HEATING
ENDS. THE HRRR HAS COME AROUND TO THIS IDEA THUS WILL INCLUDE
SLIGHT CHC POPS THIS EVENING FOR WESTERN CWA. AFTER THIS EVENING
THE REST OF THE FORECAST LOOKS MAINLY DRY WITH RELATIVELY MILD
TEMPERATURES AS SFC HIGH BUILDS IN AND THEN REMAINS IN COMMAND FOR
A COUPLE DAYS.
.LONG TERM...THURSDAY THROUGH MONDAY
IT FINALLY APPEARS THE REGION WILL STAY IN A MILD/WARM PATTERN
INTO AT LEAST EARLY NEXT WEEK. TO START OFF THE PERIOD THURSDAY
AND FRIDAY...MUCH OF THE CWA IS STILL FEELING EFFECTS OF STABLE
SURFACE HIGH AS IT SLOWLY DEPARTS TO THE EAST. CONFINED PRECIP
CHANCES TO MAINLY WESTERN PORTIONS OF THE AREA DURING THIS TIME.
THINGS GET MORE INTERESTING...WHILE AT THE SAME TIME...MORE
UNCERTAIN AS WE HEAD INTO THE WEEKEND AND EARLY NEXT WEEK. MODELS
WOULD SUGGEST A BIT MORE MOISTURE CREEPING NORTHWARD INTO THE
REGION WITH PERHAPS DEWPOINTS AROUND 60 DEGREES. INSTABILITY
INCREASES WITH UPPER LEVEL DISTURBANCES CROSSING THE REGION. IT
WOULD APPEAR PATTERN TRIES TO GET STORMIER THIS WEEKEND INTO EARLY
NEXT WEEK...WHILE STAYING MILD. COULD BE LOOKING AT A FEW ROUNDS
OF THUNDERSTORMS. THERE ARE SOME DIFFERENCES AMONGST THE MODELS IN
REGARDS TO THEIR HANDLING OF THE MAIN UPPER LOW AS IT EJECTS OUT
INTO THE PLAINS. ALTHOUGH...OVERALL BIGGER PICTURE SHOWS SEVERAL
WAVES OF ENERGY EJECTING ACROSS THE CENTRAL AND NORTHERN PLAINS AS
THIS UPPER LOW SLOWLY MOVES OUT OVER THE PLAINS.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
EXPECT VFR CONDITIONS TO PERSIST THROUGH AT LEAST TUESDAY
AFTERNOON. A FEW MODEL SOLUTIONS STILL SHOWCASE VFR/MVFR STRATUS
UP ALONG THE INTERNATIONAL BORDER TO WORK ITS WAY SOUTHWARD INTO
THE REGION TUESDAY AND TUESDAY NIGHT. CONFIDENCE IN THAT OCCURRING
IS A LITTLE LOW AT THIS POINT. WILL CONTINUE TO MONITOR
SATELLITE/OBS DATA FOR THAT SCENARIO TO DEVELOP. BUT FOR THE TIME
BEING...A DRY VFR FORECAST WILL BE MAINTAINED.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...TDK
LONG TERM...TMT
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 PM CDT MON MAY 19 2014
.UPDATE...
ISSUED AT 904 PM CDT MON MAY 19 2014
THE MAIN FOCUS THIS EVENING HAS BEEN ON THE POTENTIAL FOR FLOODING
ACROSS NORTH CENTRAL WISCONSIN WHERE MAINLY LIGHT TO MODERATE RAIN
HAS BEEN FALLING FOR MUCH OF THE DAY...BUT A ROUND OF CONVECTION
CAME THROUGH EARLIER AND NOW HAS RETREATED TO THE SOUTH ACROSS
CLARK COUNTY. ALL SHORT TERM MESO/SYNOPTIC GUIDANCE HAD THIS
CONVECTION WELL TO THE NORTHEAST BY NOW...BUT IT APPEARS TO BE
HANGING ON TO THE NOSE OF THE LOW LEVEL JET/MOISTURE TRANSPORT
THAT IS ANGLING UP FROM THE SOUTHWEST INTO THE CONVECTION. BASED
ON THE PAST HOUR/TWO OF RADAR LOOPS...IT APPEARS THAT THERE HAS
BEEN A SLIGHT SHIFT NORTHEAST OF THIS MAIN BAND OF
CONVECTION...BUT IT WILL LIKELY NOT TRACK TO THE NORTHEAST TOO
QUICKLY. THE 20.01Z RAP DOES TAKE THE LLJ TO THE EAST AFTER
MIDNIGHT...SO EXPECT THAT THE PRECIPITATION SHOULD SHIFT AWAY FROM
CLARK/TAYLOR AT THAT POINT. FLASH FLOOD GUIDANCE IS AROUND 3
INCHES AND IT DOES NOT LOOK LIKE WE WILL HIT THAT OVER A SHORT
ENOUGH OF A TIME PERIOD TO BE ISSUING WARNINGS AT THIS POINT.
TO THE SOUTHWEST OF THIS AREA...HAVE HAD SOME SCATTERED RAIN
SHOWERS AND DRIZZLE DEVELOPED UNDER THE LLJ AND WILL LIKELY
CONTINUE UNTIL THE LLJ SHIFT EAST LATER ON. THERE IS SOME QUESTION
ABOUT WHETHER ANY FOG WOULD FORM OVERNIGHT...BUT CLOUD COVER
EXTENDS WEST THROUGH MUCH OF WESTERN MINNESOTA AND IOWA. IF SKIES
CAN CLEAR OUT...THEN THE LIGHT WINDS AND RECENT RAIN WILL LIKELY
LEAD TO SOME FOG FORMATION BUT CHANCES OF IT OCCURRING ARE BETTER
TO THE WEST.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 215 PM CDT MON MAY 19 2014
LOW LEVEL WARM AIR ADVECTION/MOISTURE TRANSPORT ARE THE MAIN DRIVERS
FOR AREAS OF PCPN MOVING ACROSS THE REGION THIS AFTERNOON. SOME
THUNDER WITH THE SHOWERS...DESPITE THE PCPN RUNNING OUT OF
THE MAIN CAPE AXIS ACROSS THE PLAINS/WESTERN MN.
THE LOW LEVEL THERMODYNAMICS AND NOSE OF THE MOISTURE TRANSPORT
SHIFT ACROSS NORTHEAST WI TONIGHT...AND SO WILL THE FAVORED AREAS
FOR PCPN. INSTABILITY DOES INCREASE OVERNIGHT...WITH MUCAPES FROM 500-
1000 J/KG PER THE GFS/NAM. THIS COULD EXTEND SOME PCPN CHANCES BACK
TO THE SOUTHWEST...NEAR A WEAK TROUGH/FRONT ON THE LEADING EDGE OF
AN UPPER LEVEL SHORTWAVE. THE HIGHER QPF AND BEST CHANCES WILL BE TO
THE NORTH TONIGHT/OVERNIGHT...BUT WILL LIKELY HOLD ONTO SOME PCPN
CHANCES TO ACCOUNT FOR THE POTENTIAL ASSOCIATED WITH THE
BOUNDARY/INSTABILITY.
ON TUESDAY...THIS BOUNDARY LAYS UP WEST TO EAST ACROSS CENTRAL
IA/SOUTHERN WI...AND COULD SERVE AS A SHOWER/STORM FOCUS LATER IN
THE AFTERNOON. THE GFS AND NAM SUGGEST 2000+ J/KG SBCAPE INTO
SOUTHEAST MN/WESTERN WI BY 18Z...WITH 50 KTS OF 0-6 KM SHEAR. THE
SBCAPE IS BASED OFF OF LOW/MID 60S TDS WORKING INTO CENTRAL WI ON
WI. THIS LOOKS OVERDONE BASED ON WHAT IS OCCURRING OUT TO THE
WEST...AND THE LACK OF EVAPORTRANSPIRATION FROM CROPS TO AID IN
HIGHER TDS. DEWPOINTS IN THE UPPER 50S LOOK MORE LIKELY...THUS
LOWERING CAPE QUITE A BIT. FORCING MECHANISM ALSO LOOKS TO BE JUST
SOUTH OF THE FORECAST AREA...BUT CLOSE ENOUGH THAT PCPN CHANCES ARE
WARRANTED FOR PARTS OF NORTHEAST IA/SOUTHWEST WI.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 215 PM CDT MON MAY 19 2014
THE GFS AND ECMWF FAVOR GOING ZONAL TO RIDGING FOR THE LATER PART OF
THE WORK WEEK INTO THE UPCOMING WEEKEND WITH THE UPPER LEVEL FLOW.
AT THE SURFACE...HIGH PRESSURE MEANDERS DOWN FROM SOUTHERN
CANADA...SLIDING ACROSS THE REGION...AND GRADUALLY MOVING OVER THE
OH RIVER VALLEY BY 12Z SAT. A DRY...VERY PLEASANT FEW DAYS SHOULD
RESULT...WITH HIGHS AT OR ABOVE THE SEASONABLE NORMALS.
FINALLY...SOME NICE SPRING DAYS.
SOME DIFFERENCES IN THE MODELS FOR THE END OF THE WEEKEND...WITH THE
EC SUGGESTING AN UPPER LEVEL SHORTWAVE TROUGH COULD SLIDE ACROSS
NORTHERN PARTS OF THE REGION SUNDAY NIGHT-MONDAY. THE GFS FAVORS
RIDGING. HOWEVER...WITH THE SFC HIGH OFF TO THE EAST...SOUTHERLY
FLOW ON ITS BACKSIDE PUSH WARM/MOIST AIR TOWARD THE REGION. THIS
THERMODYNAMIC FORCING COULD RESULT IN SOME
SHOWERS/STORMS...REGARDLESS OF ANY UPPER LEVEL AID. WILL HOLD WITH
CONSENSUS SOLUTION FOR DETAILS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1136 PM CDT MON MAY 19 2014
SOME LIGHT RAIN SHOWERS AND DRIZZLE CONTINUES TO LINGER ACROSS THE
REGION AS A TROUGH LIFTS THROUGH. CONDITIONS ARE MAINLY VFR
LOCALLY WITH JUST A FEW SPOTS DROPPING DOWN WITH VISIBILITY OF 5SM
DUE TO THE RAIN SHOWERS IN SOUTH CENTRAL MINNESOTA. IF SKIES CAN
CLEAR OUT...THEN THERE WILL BE A CHANCE OF GETTING SOME DENSE FOG
DEVELOPMENT AT RST. THE BACK EDGE OF THE MID CLOUDS APPEARS TO BE
INTO SOUTH CENTRAL MINNESOTA AND IS CURRENTLY TIMED TO GET INTO
RST AROUND 7 OR 8Z AND PERHAPS INTO LSE AROUND 10Z. SOME
VISIBILITY DROPS TO IFR WILL BE POSSIBLE SHOULD THIS OCCUR
OVERNIGHT DUE TO THE LIGHT WINDS AND RAIN THAT FELL EARLIER ON
MONDAY. OTHERWISE...WINDS WILL SHIFT TO THE NORTHWEST/WEST ON
TUESDAY BUT REMAIN FAIRLY LIGHT.
&&
.HYDROLOGY...
ISSUED AT 331 AM CDT MON MAY 19 2014
WATER LEVELS ON THE MISSISSIPPI ARE BEGINNING TO GO DOWN WITH SOME
LOCATIONS FALLING BELOW FLOOD STAGE FROM LA CROSSE AND NORTH.
MINOR FLOODING WILL CONTINUE UNTIL LATE IN THE WEEK FOR SITES
SOUTH OF LA CROSSE WHERE THE CREST IS JUST NOW ARRIVING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...HALBACH
HYDROLOGY....04
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
846 AM PDT TUE MAY 20 2014
.SYNOPSIS...AN UPPER LEVEL SYSTEM DROPPING SOUTHWARD ACROSS THE
REGION WILL MAINTAIN COOL TEMPERATURES AND BRING ISOLATED SHOWERS
AND THUNDERSTORMS TO THE REGION TODAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE EXITING SYSTEM RESULTING IN DRY CONDITIONS AND A
WARMING TREND THROUGH THE MEMORIAL DAY WEEKEND.
&&
.DISCUSSION...AS OF 08:45 AM PDT TUESDAY...A FEW LIGHT SHOWERS
MOVING THROUGH AREAS FROM SAN JOSE SOUTH THIS MORNING. THE
GREATEST TOTALS ARE FROM THE SANTA LUCIA MOUNTAINS JUST SOUTH OF
MONTEREY WHERE NEARLY TWO TENTHS OF INCH WERE RECORDED. ELSEWHERE
RAINFALL OVERNIGHT ADDED UP TO A FEW HUNDREDTHS IN SOME SPOTS SPOTS.
AS THE LOW CENTER SHIFTS EASTWARD TODAY SO WILL THE POTENTIAL FOR
SHOWERS...LIKELY CONFINED TO THE INTERIOR MOUNTAINS OF SAN BENITO
COUNTY AND EASTERN DIABLO RANGE. FORECAST ON TRACK AND NO MAJOR
UPDATES REQUIRED AT THIS TIME.
&&
.PREV DISCUSSION...AS OF 03:50 AM PDT TUESDAY...LATEST ANALYSIS
INDICATES THE MID/UPPER LEVEL LOW IS CURRENTLY CENTERED OVER THE
SAN FRANCISCO BAY AREA. THIS SYSTEM BROUGHT ISOLATED RAIN SHOWERS
TO THE REGION LATE MONDAY NIGHT AND EARLY THIS MORNING. AS THE
UPPER LOW SLIDES SOUTHEASTWARD ACROSS THE CENTRAL COAST OVER THE
NEXT 12 HOURS...ISOLATED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ACROSS INTERIOR PORTIONS OF THE REGION. HOWEVER...THE
FORECAST MODELS KEEP THE BEST MOISTURE AND INSTABILITY TO OUR EAST
THROUGH THE DAY. CHANCES FOR PRECIPITATION DIMINISH TONIGHT AS THE
LOW SHIFTS EASTWARD AND DRIER AIR ALOFT MOVES ACROSS THE REGION.
THE AFOREMENTIONED SYSTEM WILL CONTINUE TO PULL WAY FROM THE REGION
AND FORECAST MODELS ARE IN GOOD AGREEMENT WITH REBUILDING A
MID/UPPER LEVEL RIDGE ACROSS THE EASTERN PACIFIC BEGINNING
WEDNESDAY. THE RIDGE WILL THEN STRENGTHEN AND SHIFT ALONG THE WEST
COAST THROUGH LATE WEEK AND PERSIST INTO THE UPCOMING HOLIDAY
WEEKEND. THIS WILL RESULT IN A WARMING TREND THAT WILL BEGIN ON
WEDNESDAY AND PERSIST THROUGH AT LEAST THE WEEKEND. ALONG WITH
WARMER TEMPERATURES...DRY CONDITIONS WILL PERSIST REGION-WIDE WITH
HIGH PRESSURE DOMINATING OUR WEATHER PATTERN.
EARLY NEXT WEEK THE MODELS SUGGEST THE RIDGE WILL BE REPLACED BY
ANOTHER TROUGH THAT WILL IMPACT THE PACIFIC NORTHWEST. HOWEVER...NO
REAL SIGNS OF PRECIPITATION CHANCES. HOWEVER...THIS WILL KEEP
TEMPERATURES FROM BECOMING TOO WARM.
&&
.AVIATION...AS OF 4:30 AM PDT TUESDAY...ABUNDANT LOW LEVEL
MOISTURE FROM AN UPPER LOW MOVING SOUTH THROUGH THE AREA...ALLOWED
LOW AND MID LEVEL CLOUDS TO RAPIDLY FORM OVERNIGHT OVER THE ENTIRE
AREA. IN GENERAL...THE FORECAST MODELS DID NOT INITIALIZE WELL WITH
REGARDS TO CLOUDS...SO CONFIDENCE IS LOW. THE HRRR SEEMS TO BE THE
ONLY MODELS WHICH HAS A GRASP ON THE RAPID FORMATION OF
CLOUDS...WHICH INDICATES DISSIPATION BETWEEN 16Z AND 18Z. AGAIN
LOW CONFIDENCE. ONSHORE GRADIENT IS FORECAST TO BE A BIT WEAKER
THIS AFTERNOON COMPARED TO YESTERDAY AFTERNOON...WITH LIGHT TO
MODERATE ONSHORE WINDS THIS AFTERNOON INTO THE EARLY EVENING HOURS.
VICINITY OF KSFO...PATCHY MVFR CIGS BETWEEN 1500 AND 2000 FEET
THROUGH 17Z. LOW CONFIDENCE. OTHERWISE...MODERATE WEST WINDS TO 18
KT.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...PATCHY MVFR CIGS THROUGH 18Z. LOW
CONFIDENCE.
&&
.MARINE...AS OF 8:30 AM PDT TUESDAY...NORTHERLY WINDS WILL
GRADUALLY INCREASE TONIGHT AS HIGH PRESSURE BUILDS OVER THE
EASTERN PACIFIC. A SOUTHERLY SWELL WILL CONTINUE TO IMPACT THE
CENTRAL COAST WITH A PERIOD OF 15-17 SEC. THE SOUTHERLY SWELL
HEIGHT WILL BE RATHER SMALL TOO...2-3 FT.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PT REYES 10-60 NM FROM 9 AM
SCA...PT ARENA TO PT REYES 0-10 NM FROM NOON
&&
$$
PUBLIC FORECAST: AC/RGASS
AVIATION: RILEY
MARINE: MM
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS RENO NV
809 AM PDT TUE MAY 20 2014
.UPDATE...
REPORTS OF LOCALIZED SNOW AMOUNTS OF UP TO 7 INCHES AROUND DAGGET
PASS HAVE BEEN REPORTED THIS MORNING WITH 2-3 INCHES AROUND SOUTH
LAKE TAHOE AT 6200 FEET. NORTH TAHOE AND INTERSTATE 80 HAVE
REMAINED DRY. SNOW ON MOST ROADWAYS HAS ALREADY MELTED.
ADDITIONAL BANDS OF PRECIPITATION ARE EXPECTED THROUGH EARLY
AFTERNOON WITH SNOW LEVELS VARYING WIDELY DEPENDING ON THE
INTENSITY OF PRECIPITATION. ROAD TEMPERATURES IN MOST AREAS OUTSIDE
OF SOUTH LAKE TAHOE ARE ABOVE FREEZING WHICH WILL HELP RESIST SNOW
ACCUMULATIONS. ADDITIONAL SNOW ACCUMULATIONS, SIGNIFICANT AT
TIMES, WILL REMAIN POSSIBLE THIS MORNING IN THE SIERRA BUT SHOULD
QUICKLY MELT AS SOON AS HEAVY PRECIPITATION CEASES. TOLBY
&&
.SYNOPSIS...
LOW PRESSURE ON THE NORTHERN COAST OF CALIFORNIA WILL REACH THE
SIERRA AND WESTERN NEVADA TODAY. THIS WILL BRING COOLER AND BREEZY
CONDITIONS ALONG WITH RAIN SHOWERS, ISOLATED THUNDERSTORMS AND HIGH
ELEVATION SNOW THROUGH EARLY THURSDAY. HIGH PRESSURE WILL SLOWLY
BUILD BACK INTO THE SOUTHWEST BRINGING WARMER AND DRIER CONDITIONS
FOR THE END OF THE WEEK.
&&
.PREVIOUS DISCUSSION... /ISSUED 633 AM PDT TUE MAY 20 2014/
UPDATE...
BASED OFF LATEST RADAR TRENDS AND HRRR MODEL RUNS WE ARE GOING
WITH A WINTER WEATHER ADVISORY FOR LAKE TAHOE TODAY. CALTRANS
WEBCAMS SHOW SNOW COVERED ROADS AROUND SOUTH LAKE TAHOE THIS
MORNING AND THE SNOW IS EXPECTED TO CONTINUE THROUGH THE MORNING.
WE WILL RUN THE ADVISORY THROUGH 2 PM THIS AFTERNOON, AS THE SNOW
LEVELS SHOULD RISE THROUGH THE DAY. HOON
PREVIOUS DISCUSSION... /ISSUED 527 AM PDT TUE MAY 20 2014/
UPDATE...
MADE SOME ADJUSTMENTS TO THE MORNING WEATHER DUE TO SNOW LEVELS
FALLING LOWER THAN EXPECTED. SNOW IS CURRENTLY FALLING IN SOUTH
LAKE TAHOE, AS SEEN ON CALTRANS WEBCAMS AND KTVL ASOS. SNOW LEVEL
ESTIMATES AROUND TAHOE ARE AT 6000 FEET, SO HAVE ADJUSTED THE
FORECAST TO SHOW SNOW AROUND THE LAKE IN THE MORNING, THEN
BECOMING RAIN LATE THIS MORNING AS WE GET SOME WARMING AND THE LOW
STARTS TO PUSH EASTWARD. SNOW AMOUNTS WILL GENERALLY BE ON GRASSY
AND ELEVATED SURFACES AROUND THE LAKE, AS ROAD TEMPERATURES ARE
ABOVE FREEZING.
THERE ARE SOME CONCERNS ABOUT SLICK ROADS OVER THE PASSES AROUND
TAHOE, INCLUDING ECHO SUMMIT, CARSON PASS, SPOONER SUMMIT, MOUNT
ROSE SUMMIT, ETC... THERE ARE CURRENTLY NO CHAIN CONTROLS IN
EFFECT AS OF 530AM TUESDAY, BUT ANY TRAVELERS GOING OVER THE
PASSES TODAY SHOULD BE PREPARED FOR SLICK CONDITIONS AND WINTER
DRIVING CONDITIONS. HOON
PREVIOUS DISCUSSION... /ISSUED 228 AM PDT TUE MAY 20 2014/
SHORT TERM...
NO MAJOR ADJUSTMENTS TO THE ON-GOING FORECAST AS MODELS CONTINUE
TO SWING LOW PRESSURE THROUGH CENTRAL CALIFORNIA INTO NEVADA TODAY
AND TONIGHT. THE MOST UNCERTAINTY LIES WITH HOW MUCH TOTAL
PRECIPITATION ANY GIVEN LOCATION WILL RECEIVE AND HOW LONG THE
LOW WILL LINGER. STILL LOOKING AT THE POTENTIAL FOR OVER 0.5
INCHES TO ABOUT 0.75 INCHES FOR THE FORECAST AREA. SOME LOCAL
VARIATION WILL BE LIKELY ESPECIALLY TOWARDS MONO COUNTY. THIS AREA
WILL BE INFLUENCED BY A DEVELOPING LEE SIDE SURFACE LOW WHICH MAY
ADD ADDITIONAL TOTALS THROUGH UPSLOPING. THIS INFLUENCE LOOKS
WEAKER FROM 24 HOURS AGO, BUT PROBABILITY COULD SWAY IN FAVOR OF
HIGHER LIQUID TOTALS IF THE LOW DEVELOPS AND LINGERS. SUBTLE
ADJUSTMENTS WERE MADE TO LINGER THE DEFORMATION BY A FEW HOURS.
HOWEVER, SHORT TERM MODELS AGREE THAT THE LOW WILL MEANDER
SOUTHEAST PULLING ANY RAIN WITH IT BY LATE THURSDAY MORNING.
OTHERWISE, CHARACTER OF PRECIPITATION WILL SHIFT FROM SHOWERY
NATURE TO MORE STRATIFORM TYPE AS DEFORMATION TAKES OVER AS THE
MAIN FORCING MECHANISM. SNOW LEVELS SHOULD DROP TO ABOUT 7000 FEET
LATE THIS MORNING BEFORE LIFTING BACK TO AROUND 8000 FEET BY THIS
EVENING. SNOW SHOWERS WILL IMPACT THE HIGHER SIERRA PASSES WITH
SOME LIGHT ACCUMULATIONS POSSIBLE ABOVE 7000 FEET. WILL NEED TO
KEEP AN EYE ON PRECIPITATION RATES WHICH COULD DRAG THE SNOW LEVEL
INTERMITTENTLY BELOW 7000 FEET. THE ONLY OTHER NOTABLE WEATHER
PARAMETER WILL BE WINDS. WHILE THIS SYSTEM IS NOT OVERLY ROBUST,
SUSTAINED WIND SPEEDS WILL REMAIN CONSISTENTLY 15 TO 20 MPH FOR
THE NEXT COUPLE OF DAYS. WINDS COULD BE HIGHER EAST OF HIGHWAY 95
WITH GUSTS TO 40 MPH AS THE LEE SIDE LOW RAMPS UP. BOYD
LONG TERM...FRIDAY THROUGH MONDAY...
RIDGING CONTINUES TO BUILD INTO CA/NV AS WE GO INTO THE WEEKEND.
TEMPERATURES ALOFT WILL WARM UP SHARPLY WITH 700MB TEMPS GETTING UP
TO NEAR +10C THIS WEEKEND. THIS WILL PUSH TEMPERATURES WELL INTO THE
MID 80S ACROSS THE DESERT VALLEYS WITH 70S IN THE SIERRA VALLEYS ON
SATURDAY AND SUNDAY.
LATEST GFS AND ECMWF MOS GUIDANCE HAS SETTLED INTO THE MID 80S FOR
RENO OVER THE WEEKEND. ALTHOUGH WITH 700MB TEMPS POTENTIALLY RISING
ABOVE +10C, WE MAY NEED TO RAISE THE TEMPERATURES EVEN MORE.
FORECAST CONFIDENCE IS RISING WITH RESPECT TO WELL ABOVE NORMAL
TEMPERATURES FOR THE WEEKEND AS NOW THE ECMWF AND GFS ARE IN BETTER
AGREEMENT. EXPECT TEMPERATURES ACROSS THE REGION TO BE AT LEAST 10
DEGREES ABOVE NORMAL.
THE OTHER FEATURE THAT HAS INCREASING SUPPORT FROM THE GFS/ECMWF/GEM
IS A DEEP TROUGH MOVING INTO THE PACIFIC NORTHWEST BY MONDAY. MOST
OF THE MOISTURE AND JET DYNAMICS WILL REMAIN WELL TO THE NORTH,
MEANING THAT WE WILL SEE MOSTLY DRY CONDITIONS AND STRONG GUSTY
WINDS BY MONDAY. WE WILL NEED TO KEEP A CLOSE EYE ON THIS WIND
EVENT, AS IT MAY POSE FIRE WEATHER CONCERNS FOR THE REGION. HOON
AVIATION...
THE APPROACHING LOW PRESSURE SYSTEM IS ALREADY BRINGING SHOWERS AND
THUNDERSTORMS INTO THE SIERRA AND WESTERN NEVADA. WIDESPREAD RAIN
SHOWERS WILL AFFECT KRNO-KTRK-KTVL-KLOL-KNFL TODAY WITH A FEW
ISOLATED THUNDERSTORMS MIXED IN AS WELL. MVFR CIGS WILL BE POSSIBLE
TODAY AT AREA TERMINALS, ESPECIALLY DURING HEAVIER RAINFALL. SHOWERS
WILL LAST THROUGH MOST OF THE DAY TODAY, THEN SHIFTING SOUTH AND
EAST AFTER 03Z WEDNESDAY. RAIN AND HIGH ELEVATION SNOW WILL SHIFT
SOUTH TOWARDS KMMH BETWEEN 00-12Z WEDNESDAY BRINGING A MIX OF RAIN,
SNOW, AND MVFR CIGS. HOON
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY UNTIL 2 PM PDT THIS AFTERNOON NVZ002.
CA...WINTER WEATHER ADVISORY UNTIL 2 PM PDT THIS AFTERNOON CAZ072.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
633 AM PDT TUE MAY 20 2014
.UPDATE...
BASED OFF LATEST RADAR TRENDS AND HRRR MODEL RUNS WE ARE GOING
WITH A WINTER WEATHER ADVISORY FOR LAKE TAHOE TODAY. CALTRANS
WEBCAMS SHOW SNOW COVERED ROADS AROUND SOUTH LAKE TAHOE THIS
MORNING AND THE SNOW IS EXPECTED TO CONTINUE THROUGH THE MORNING.
WE WILL RUN THE ADVISORY THROUGH 2 PM THIS AFTERNOON, AS THE SNOW
LEVELS SHOULD RISE THROUGH THE DAY. HOON
&&
.PREVIOUS DISCUSSION... /ISSUED 527 AM PDT TUE MAY 20 2014/
UPDATE...
MADE SOME ADJUSTMENTS TO THE MORNING WEATHER DUE TO SNOW LEVELS
FALLING LOWER THAN EXPECTED. SNOW IS CURRENTLY FALLING IN SOUTH
LAKE TAHOE, AS SEEN ON CALTRANS WEBCAMS AND KTVL ASOS. SNOW LEVEL
ESTIMATES AROUND TAHOE ARE AT 6000 FEET, SO HAVE ADJUSTED THE
FORECAST TO SHOW SNOW AROUND THE LAKE IN THE MORNING, THEN
BECOMING RAIN LATE THIS MORNING AS WE GET SOME WARMING AND THE LOW
STARTS TO PUSH EASTWARD. SNOW AMOUNTS WILL GENERALLY BE ON GRASSY
AND ELEVATED SURFACES AROUND THE LAKE, AS ROAD TEMPERATURES ARE
ABOVE FREEZING.
THERE ARE SOME CONCERNS ABOUT SLICK ROADS OVER THE PASSES AROUND
TAHOE, INCLUDING ECHO SUMMIT, CARSON PASS, SPOONER SUMMIT, MOUNT
ROSE SUMMIT, ETC... THERE ARE CURRENTLY NO CHAIN CONTROLS IN
EFFECT AS OF 530AM TUESDAY, BUT ANY TRAVELERS GOING OVER THE
PASSES TODAY SHOULD BE PREPARED FOR SLICK CONDITIONS AND WINTER
DRIVING CONDITIONS. HOON
PREVIOUS DISCUSSION... /ISSUED 228 AM PDT TUE MAY 20 2014/
SYNOPSIS...
LOW PRESSURE ON THE NORTHERN COAST OF CALIFORNIA WILL REACH THE
SIERRA AND WESTERN NEVADA TODAY. THIS WILL BRING COOLER AND BREEZY
CONDITIONS ALONG WITH RAIN SHOWERS, ISOLATED THUNDERSTORMS AND HIGH
ELEVATION SNOW THROUGH EARLY THURSDAY. HIGH PRESSURE WILL SLOWLY
BUILD BACK INTO THE SOUTHWEST BRINGING WARMER AND DRIER CONDITIONS
FOR THE END OF THE WEEK.
SHORT TERM...
NO MAJOR ADJUSTMENTS TO THE ON-GOING FORECAST AS MODELS CONTINUE
TO SWING LOW PRESSURE THROUGH CENTRAL CALIFORNIA INTO NEVADA TODAY
AND TONIGHT. THE MOST UNCERTAINTY LIES WITH HOW MUCH TOTAL
PRECIPITATION ANY GIVEN LOCATION WILL RECEIVE AND HOW LONG THE
LOW WILL LINGER. STILL LOOKING AT THE POTENTIAL FOR OVER 0.5
INCHES TO ABOUT 0.75 INCHES FOR THE FORECAST AREA. SOME LOCAL
VARIATION WILL BE LIKELY ESPECIALLY TOWARDS MONO COUNTY. THIS AREA
WILL BE INFLUENCED BY A DEVELOPING LEE SIDE SURFACE LOW WHICH MAY
ADD ADDITIONAL TOTALS THROUGH UPSLOPING. THIS INFLUENCE LOOKS
WEAKER FROM 24 HOURS AGO, BUT PROBABILITY COULD SWAY IN FAVOR OF
HIGHER LIQUID TOTALS IF THE LOW DEVELOPS AND LINGERS. SUBTLE
ADJUSTMENTS WERE MADE TO LINGER THE DEFORMATION BY A FEW HOURS.
HOWEVER, SHORT TERM MODELS AGREE THAT THE LOW WILL MEANDER
SOUTHEAST PULLING ANY RAIN WITH IT BY LATE THURSDAY MORNING.
OTHERWISE, CHARACTER OF PRECIPITATION WILL SHIFT FROM SHOWERY
NATURE TO MORE STRATIFORM TYPE AS DEFORMATION TAKES OVER AS THE
MAIN FORCING MECHANISM. SNOW LEVELS SHOULD DROP TO ABOUT 7000 FEET
LATE THIS MORNING BEFORE LIFTING BACK TO AROUND 8000 FEET BY THIS
EVENING. SNOW SHOWERS WILL IMPACT THE HIGHER SIERRA PASSES WITH
SOME LIGHT ACCUMULATIONS POSSIBLE ABOVE 7000 FEET. WILL NEED TO
KEEP AN EYE ON PRECIPITATION RATES WHICH COULD DRAG THE SNOW LEVEL
INTERMITTENTLY BELOW 7000 FEET. THE ONLY OTHER NOTABLE WEATHER
PARAMETER WILL BE WINDS. WHILE THIS SYSTEM IS NOT OVERLY ROBUST,
SUSTAINED WIND SPEEDS WILL REMAIN CONSISTENTLY 15 TO 20 MPH FOR
THE NEXT COUPLE OF DAYS. WINDS COULD BE HIGHER EAST OF HIGHWAY 95
WITH GUSTS TO 40 MPH AS THE LEE SIDE LOW RAMPS UP. BOYD
LONG TERM...FRIDAY THROUGH MONDAY...
RIDGING CONTINUES TO BUILD INTO CA/NV AS WE GO INTO THE WEEKEND.
TEMPERATURES ALOFT WILL WARM UP SHARPLY WITH 700MB TEMPS GETTING UP
TO NEAR +10C THIS WEEKEND. THIS WILL PUSH TEMPERATURES WELL INTO THE
MID 80S ACROSS THE DESERT VALLEYS WITH 70S IN THE SIERRA VALLEYS ON
SATURDAY AND SUNDAY.
LATEST GFS AND ECMWF MOS GUIDANCE HAS SETTLED INTO THE MID 80S FOR
RENO OVER THE WEEKEND. ALTHOUGH WITH 700MB TEMPS POTENTIALLY RISING
ABOVE +10C, WE MAY NEED TO RAISE THE TEMPERATURES EVEN MORE.
FORECAST CONFIDENCE IS RISING WITH RESPECT TO WELL ABOVE NORMAL
TEMPERATURES FOR THE WEEKEND AS NOW THE ECMWF AND GFS ARE IN BETTER
AGREEMENT. EXPECT TEMPERATURES ACROSS THE REGION TO BE AT LEAST 10
DEGREES ABOVE NORMAL.
THE OTHER FEATURE THAT HAS INCREASING SUPPORT FROM THE GFS/ECMWF/GEM
IS A DEEP TROUGH MOVING INTO THE PACIFIC NORTHWEST BY MONDAY. MOST
OF THE MOISTURE AND JET DYNAMICS WILL REMAIN WELL TO THE NORTH,
MEANING THAT WE WILL SEE MOSTLY DRY CONDITIONS AND STRONG GUSTY
WINDS BY MONDAY. WE WILL NEED TO KEEP A CLOSE EYE ON THIS WIND
EVENT, AS IT MAY POSE FIRE WEATHER CONCERNS FOR THE REGION. HOON
AVIATION...
THE APPROACHING LOW PRESSURE SYSTEM IS ALREADY BRINGING SHOWERS AND
THUNDERSTORMS INTO THE SIERRA AND WESTERN NEVADA. WIDESPREAD RAIN
SHOWERS WILL AFFECT KRNO-KTRK-KTVL-KLOL-KNFL TODAY WITH A FEW
ISOLATED THUNDERSTORMS MIXED IN AS WELL. MVFR CIGS WILL BE POSSIBLE
TODAY AT AREA TERMINALS, ESPECIALLY DURING HEAVIER RAINFALL. SHOWERS
WILL LAST THROUGH MOST OF THE DAY TODAY, THEN SHIFTING SOUTH AND
EAST AFTER 03Z WEDNESDAY. RAIN AND HIGH ELEVATION SNOW WILL SHIFT
SOUTH TOWARDS KMMH BETWEEN 00-12Z WEDNESDAY BRINGING A MIX OF RAIN,
SNOW, AND MVFR CIGS. HOON
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY UNTIL 2 PM PDT THIS AFTERNOON NVZ002.
CA...WINTER WEATHER ADVISORY UNTIL 2 PM PDT THIS AFTERNOON CAZ072.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
431 AM PDT TUE MAY 20 2014
.SYNOPSIS...AN UPPER LEVEL SYSTEM DROPPING SOUTHWARD ACROSS THE
REGION WILL MAINTAIN COOL TEMPERATURES AND BRING ISOLATED SHOWERS
AND THUNDERSTORMS TO THE REGION TODAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE EXITING SYSTEM RESULTING IN DRY CONDITIONS AND A
WARMING TREND THROUGH THE MEMORIAL DAY WEEKEND.
&&
.DISCUSSION...AS OF 03:50 AM PDT TUESDAY...LATEST ANALYSIS
INDICATES THE MID/UPPER LEVEL LOW IS CURRENTLY CENTERED OVER THE
SAN FRANCISCO BAY AREA. THIS SYSTEM BROUGHT ISOLATED RAIN SHOWERS
TO THE REGION LATE MONDAY NIGHT AND EARLY THIS MORNING. AS THE
UPPER LOW SLIDES SOUTHEASTWARD ACROSS THE CENTRAL COAST OVER THE
NEXT 12 HOURS...ISOLATED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ACROSS INTERIOR PORTIONS OF THE REGION. HOWEVER...THE
FORECAST MODELS KEEP THE BEST MOISTURE AND INSTABILITY TO OUR EAST
THROUGH THE DAY. CHANCES FOR PRECIPITATION DIMINISH TONIGHT AS THE
LOW SHIFTS EASTWARD AND DRIER AIR ALOFT MOVES ACROSS THE REGION.
THE AFOREMENTIONED SYSTEM WILL CONTINUE TO PULL WAY FROM THE REGION
AND FORECAST MODELS ARE IN GOOD AGREEMENT WITH REBUILDING A
MID/UPPER LEVEL RIDGE ACROSS THE EASTERN PACIFIC BEGINNING
WEDNESDAY. THE RIDGE WILL THEN STRENGTHEN AND SHIFT ALONG THE WEST
COAST THROUGH LATE WEEK AND PERSIST INTO THE UPCOMING HOLIDAY
WEEKEND. THIS WILL RESULT IN A WARMING TREND THAT WILL BEGIN ON
WEDNESDAY AND PERSIST THROUGH AT LEAST THE WEEKEND. ALONG WITH
WARMER TEMPERATURES...DRY CONDITIONS WILL PERSIST REGION-WIDE WITH
HIGH PRESSURE DOMINATING OUR WEATHER PATTERN.
EARLY NEXT WEEK THE MODELS SUGGEST THE RIDGE WILL BE REPLACED BY
ANOTHER TROUGH THAT WILL IMPACT THE PACIFIC NORTHWEST. HOWEVER...NO
REAL SIGNS OF PRECIPITATION CHANCES. HOWEVER...THIS WILL KEEP
TEMPERATURES FROM BECOMING TOO WARM.
&&
.AVIATION...AS OF 4:30 AM PDT TUESDAY...ABUNDANT LOW LEVEL
MOISTURE FROM AN UPPER LOW MOVING SOUTH THROUGH THE AREA...ALLOWED
LOW AND MID LEVEL CLOUDS TO RAPIDLY FORM OVERNIGHT OVER THE ENTIRE
AREA. IN GENERAL...THE FORECAST MODELS DID NOT INITIALIZE WELL WITH
REGARDS TO CLOUDS...SO CONFIDENCE IS LOW. THE HRRR SEEMS TO BE THE
ONLY MODELS WHICH HAS A GRASP ON THE RAPID FORMATION OF
CLOUDS...WHICH INDICATES DISSIPATION BETWEEN 16Z AND 18Z. AGAIN
LOW CONFIDENCE. ONSHORE GRADIENT IS FORECAST TO BE A BIT WEAKER
THIS AFTERNOON COMPARED TO YESTERDAY AFTERNOON...WITH LIGHT TO
MODERATE ONSHORE WINDS THIS AFTERNOON INTO THE EARLY EVENING HOURS.
VICINITY OF KSFO...PATCHY MVFR CIGS BETWEEN 1500 AND 2000 FEET
THROUGH 17Z. LOW CONFIDENCE. OTHERWISE...MODERATE WEST WINDS TO 18
KT.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...PATCHY MVFR CIGS THROUGH 18Z. LOW
CONFIDENCE.
&&
.MARINE...AS OF 03:50 AM PDT TUESDAY...SURFACE HIGH PRESSURE OVER
THE EASTERN PACIFIC WILL STRENGTHEN THROUGH THE DAY INTO
THURSDAY...RESULTING IN MODERATE NORTHERLY WINDS THROUGH THE
WEEKEND.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PT REYES 10-60 NM FROM 9 AM
SCA...PT REYES TO PIGEON PT 10-60 NM FROM 7 PM
SCA...PIGEON PT TO PT PINOS 10-60 NM FROM 7 PM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM FROM 7 PM
SCA...PT ARENA TO PT REYES 0-10 NM FROM NOON
SCA...PT REYES TO PIGEON PT 0-10 NM FROM 7 PM
&&
$$
PUBLIC FORECAST: RGASS
AVIATION/MARINE: RILEY
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
321 AM PDT Tue May 20 2014
.Synopsis...
Cool and unsettled weather pattern continues today with showers
and thunderstorms possible across the region. The higher
elevations of the northern Sierra Nevada may see some accumulating
snow. The shower and thunderstorm threat retreats to the mountains
for Wednesday, then warmer and drier conditions return to the
entire region by the end of the week.
&&
.Discussion...
Upper low near the Bay Area early this morning. Showers and
thunderstorms have ended for the most part across the northern
Sacramento Valley, but activity is picking up in the diffluent
region ahead of the low over the northern Sierra with quite a bit
of showers and a few thunderstorms south of I-80.
The threat of showers and thunderstorms continues today as the
cold low tracks across central California. The best potential for
precipitation should be centered over the Sierra and foothills,
but HRRR brings precip into the Sacramento region around mid-day
and hints at convection over the foothills and northern Sierra
spreading back into the Sacramento Valley later this afternoon.
High mountain snow still looks to be a possibility with 1-3 inches
of snow accumulation possible above 7500 feet through tonight.
Warmer air moving in behind the low should bring quickly rising
snow levels tonight ending the potential for snow by Wednesday
morning.
The upper low moves into Nevada on Wednesday. The threat for
showers and thunderstorms will continue over the Sierra and
foothills with drier weather and much warmer temperatures for the
Valley. Warm and dry conditions continue through the weekend.
&&
.Aviation...
Generally VFR conds except for areas of MVFR conds in showers and
isolated thunderstorms and local mountain IFR conds. Freezing
level 6500-7000ft MSL. Showers will rotate around low pressure
today as the low moves SE down interior CA today. Storm movements
will shift more toward W to SW as low moves south of area this
morning. Expect more E to N winds above FL030 today. JClapp
&&
.STO Watches/Warnings/Advisories...None.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1022 AM EDT TUE MAY 20 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 326 AM EDT TUE MAY 20 2014
A WARM FRONT WILL TRAVERSE CENTRAL INDIANA TODAY...BRINGING HIGH
TEMPS BACK INTO THE 80S. THERE IS A SLIGHT CHANCE FOR SOME
SCATTERED SHOWERS AND THUNDERSTORMS ALONG THAT FRONTAL BOUNDARY OVER
NORTHERN PORTIONS OF THE AREA TONIGHT...BUT THE BEST CHANCES FOR
CONVECTION WILL BE TOMORROW WHEN A COLD FRONT HITS THE DESTABILIZED
ENVIRONMENT. ALL OF CENTRAL INDIANA IS CURRENTLY UNDER A SLIGHT
RISK FOR SEVERE THUNDERSTORMS TOMORROW AS A RESULT. FURTHER
OUT...A DRY FORECAST IS NOW EXPECTED TO PREVAIL FROM THURSDAY
THROUGH THE EXTENDED PERIOD AFTER MUCH MODEL INCONSISTENCY OVER
LAST WEEKEND. THE LAST FEW RUNS HAVE NOW SETTLED ON A DRY PATTERN
THROUGH THE EXTENDED PERIOD.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1006 AM EDT TUE MAY 20 2014
FOR THE UPDATE...INCREASED CLOUD COVER BASED ON CURRENT SATELLITE
TRENDS AND ADDED ISOLATED SPRINKLES FOR THE NEXT COUPLE OF HOURS IN
THE EASTERN COUNTIES BASED ON RADAR RETURNS. CLOUDS SHOULD THIN OUT
TO PARTLY CLOUDY FOR THE AFTERNOON THOUGH AND STILL EXPECT
TEMPERATURES TO CLIMB TO THE LOW TO MID 80S WITH GUSTY SOUTHWEST
WINDS. LATEST HRRR AND RAP ARE KEEPING THUNDERSTORMS OUT OF THE
FORECAST AREA UNTIL WELL AFTER 0Z SO KEPT DRY POP GOING THROUGH THEN
WITH SEVERE RISK NOT IN PLAY UNTIL THE TONIGHT PERIOD AS WELL.
PREVIOUS DISCUSSION FOLLOWS...
THE MAIN FOCUS OF THE NEAR TERM PERIOD IS A WARM FRONT PROGGED TO
TRACK ACROSS CENTRAL INDIANA TODAY. STRONG SOUTHWEST FLOW/WARM AIR
ADVECTION WAS MAIN FACTOR IN TRENDING ABOVE GUIDANCE FOR TODAY/S
HIGHS. THE END RESULT WAS FORECASTED HIGHS IN THE LOW TO MID 80S.
IN REGARD TO PRECIP CHANCES FOR TODAY...THE NAM REMAINS THE
OUTLYING MODEL IN BRINGING CONVECTION INTO THE NORTHERN COUNTIES
LATE THIS MORNING/AFTERNOON. HOWEVER...RAPID REFRESH IS INDICATING
DRY CONDITIONS THROUGH THE AFTERNOON...AND THE GFS IS ALSO ON
BOARD WITH THAT. DECIDED TO HOLD OFF ON THUNDERSTORM CHANCES OVER
THE NORTHERN COUNTIES UNTIL THIS EVENING WHEN DYNAMICS IMPROVE
WITH APPROACHING COLD FRONT. SPC ALSO HAS A SLIGHT RISK IN PLACE
FOR THE NORTHERN HALF OF OUR FORECAST AREA FOR DAY 1...BUT MAINLY
FOCUSING DURING THAT EVENING TIME FRAME AS WELL.
CURRENTLY...TEMPS ACROSS THE AREA ARE GENERALLY IN THE LOW 60S
WITH SOUTHEASTERLY WINDS OF 5 TO 10 MPH.
&&
.SHORT TERM /T0NIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 326 AM EDT TUE MAY 20 2014
THE MAIN FOCUS OF THE SHORT TERM PERIOD IS SEVERE THUNDERSTORM
THREAT IN ASSOCIATION WITH COLD FRONT. SPC CONTINUES TO KEEP ALL
OF CENTRAL INDIANA UNDER A SLIGHT RISK FOR DAY 2.
COLD FRONT IS EXPECTED TO ENTER A RATHER DESTABILIZED ENVIRONMENT
TOMORROW AFTERNOON. MLCAPES REMAIN IMPRESSIVE WITH SUBSTANTIAL
DAYTIME HEATING. LOW LEVEL MOISTURE REMAINS A BIT OVERDONE...BUT
SHOULD STILL BE SUFFICIENT. WESTERLY FLOW WILL BE CONSISTENT
THROUGH ALL LEVELS. THERE WILL BE A LACK OF DIRECTIONAL
SHEAR...BUT SPEED SHEAR WILL BE FAIRLY STRONG.
ACTIVITY WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST ON WEDNESDAY
EVENING AND THE REMAINDER OF SHORT TERM PERIOD WILL BE DRY. HIGHS
WILL FALL BACK INTO THE 70S FOR THURSDAY IN WAKE OF COLD FRONT.
STUCK WITH A MODEL BLEND FOR TEMPS THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MEMORIAL DAY/...
ISSUED AT 140 AM EDT TUE MAY 20 2014
MODELS AND REGIONAL BLEND IN GOOD AGREEMENT ON A DRY MEMORIAL DAY
WEEKEND...AND THIS LOOKS REASONABLE AS SURFACE HIGH PRESSURE BUILDS
IN FROM THE NORTHWEST ON FRIDAY AS AN UPPER LOW MOVES INTO THE
NORTHEASTERN STATES...AND AN UPPER RIDGE MOVES INTO THE PLAINS.
MODELS AND BLEND ALSO IN GOOD SHAPE ON TEMPERATURE TRENDS WITH COLD
ADVECTION AND 850 MILLIBAR TEMPERATURES FAVORING A SLIGHT COOL DOWN
COMPARED TO MIDWEEK WITH NEAR NORMAL AFTERNOON HIGHS IN THE LOWER TO
MID 70S LOOKING GOOD ON FRIDAY AND WARMING TO THE MID AND UPPER 70S
ON SUNDAY AND UPPER 70S AND MID 80S ON MEMORIAL DAY AS UPPER RIDGE
BUILDS IN FROM THE PLAINS AND SURFACE HIGH SHIFTS TO THE
SOUTHEASTERN STATES...WELL AHEAD OF A WESTERN FRONTAL SYSTEM.
&&
.AVIATION /DISCUSSION FOR 201500Z TAF UPDATE/...
ISSUED AT 1022 AM EDT TUE MAY 20 2014
AREA OF MID/HIGH LEVEL CLOUD DEBRIS MOVING ACROSS THE TERMINALS THIS
MORNING. EXPECT THIS TO SHIFT E/SE OF THE FORECAST AREA AROUND
MIDDAY WITH DIURNAL CU DEVELOPMENT FOR THE AFTERNOON AS CONVECTIVE
TEMPS ARE APPROACHED. ALREADY SEEING SOME GUSTY SOUTHWEST WINDS AS
THE WARM FRONT LIFTS NORTH AND HAVE ADJUSTED ACCORDINGLY. STILL
MONITORING CONVECTIVE TRENDS FOR THE EVENING AND OVERNIGHT. MODEL
SOUNDINGS SHOWING A CAPPED AIRMASS THROUGH EARLY EVENING WITH
EROSION THEREAFTER AS AIRMASS BECOMES INCREASINGLY UNSTABLE. SHORT
RANGE MODEL GUIDANCE KEEPS CONVECTION NORTHWEST OF THE FORECAST AREA
THROUGH 03Z...WITH POTENTIAL FOR GREATER IMPACTS THEREAFTER AS THE
STORMS CONGEAL INTO AN MCS. NO NEED TO CHANGE TIMING OF VCTS AT THIS
POINT...BUT WILL BE SOMETHING LOOKED AT IN GREATER DETAIL FRO THE
18Z FORECAST.
12Z DISCUSSION FOLLOWS.
VFR CONDITIONS EXPECTED THROUGH AT LEAST 00Z ACROSS THE TERMINALS.
CU DEVELOPMENT PROGS SUGGEST DIURNAL CEILINGS AFTER 16Z TO GO WITH
THE AC OUT THERE NOW.
LAF...ESPECIALLY...AND PERHAPS IND...COULD SEE MVFR CONDITIONS IN
THUNDERSTORMS ALONG WITH HIGH THUNDERSTORM WINDS IF SEVERE SQUALL
LINE DEVELOPS LATE TODAY ACROSS EASTERN IOWA OR NORTHWESTERN
ILLINOIS PER THE STORM PREDICTION CENTER DAY 1 SEVERE WEATHER
OUTLOOK. FOR NOW...CONFIDENCE IN EXACT TIMING AND PATH OF SQUALL
LINE IS NOT GREAT. SO...WILL JUST THROW IN VCTS AT LAF AFTER 04Z AND
IND AFTER 06Z...AND FINE TUNE IN SUBSEQUENT TAFS. OTHERWISE...WILL
LEAVE THUNDER OUT TONIGHT AT HUF AND BMG...WITH BETTER CONFIDENCE.
WARM FRONT SHOULD BE NORTHEAST OF THE TERMINALS AT ISSUANCE TIME
WITH SOUTHWEST WINDS NEAR 15 KNOTS GUSTING TO NEAR 20 KNOTS BY 15Z
THIS MORNING. MEANWHILE...THE COLD FRONT WILL STILL BE NORTHWEST OF
LAF BY 12Z WEDNESDAY. SOUTHWEST WINDS WILL STILL NEAR 10 KNOTS
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD/CP
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...MK/RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1006 AM EDT TUE MAY 20 2014
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 326 AM EDT TUE MAY 20 2014
A WARM FRONT WILL TRAVERSE CENTRAL INDIANA TODAY...BRINGING HIGH
TEMPS BACK INTO THE 80S. THERE IS A SLIGHT CHANCE FOR SOME
SCATTERED SHOWERS AND THUNDERSTORMS ALONG THAT FRONTAL BOUNDARY OVER
NORTHERN PORTIONS OF THE AREA TONIGHT...BUT THE BEST CHANCES FOR
CONVECTION WILL BE TOMORROW WHEN A COLD FRONT HITS THE DESTABILIZED
ENVIRONMENT. ALL OF CENTRAL INDIANA IS CURRENTLY UNDER A SLIGHT
RISK FOR SEVERE THUNDERSTORMS TOMORROW AS A RESULT. FURTHER
OUT...A DRY FORECAST IS NOW EXPECTED TO PREVAIL FROM THURSDAY
THROUGH THE EXTENDED PERIOD AFTER MUCH MODEL INCONSISTENCY OVER
LAST WEEKEND. THE LAST FEW RUNS HAVE NOW SETTLED ON A DRY PATTERN
THROUGH THE EXTENDED PERIOD.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1006 AM EDT TUE MAY 20 2014
FOR THE UPDATE...INCREASED CLOUD COVER BASED ON CURRENT SATELLITE
TRENDS AND ADDED ISOLATED SPRINKLES FOR THE NEXT COUPLE OF HOURS IN
THE EASTERN COUNTIES BASED ON RADAR RETURNS. CLOUDS SHOULD THIN OUT
TO PARTLY CLOUDY FOR THE AFTERNOON THOUGH AND STILL EXPECT
TEMPERATURES TO CLIMB TO THE LOW TO MID 80S WITH GUSTY SOUTHWEST
WINDS. LATEST HRRR AND RAP ARE KEEPING THUNDERSTORMS OUT OF THE
FORECAST AREA UNTIL WELL AFTER 0Z SO KEPT DRY POP GOING THROUGH THEN
WITH SEVERE RISK NOT IN PLAY UNTIL THE TONIGHT PERIOD AS WELL.
PREVIOUS DISCUSSION FOLLOWS...
THE MAIN FOCUS OF THE NEAR TERM PERIOD IS A WARM FRONT PROGGED TO
TRACK ACROSS CENTRAL INDIANA TODAY. STRONG SOUTHWEST FLOW/WARM AIR
ADVECTION WAS MAIN FACTOR IN TRENDING ABOVE GUIDANCE FOR TODAY/S
HIGHS. THE END RESULT WAS FORECASTED HIGHS IN THE LOW TO MID 80S.
IN REGARD TO PRECIP CHANCES FOR TODAY...THE NAM REMAINS THE
OUTLYING MODEL IN BRINGING CONVECTION INTO THE NORTHERN COUNTIES
LATE THIS MORNING/AFTERNOON. HOWEVER...RAPID REFRESH IS INDICATING
DRY CONDITIONS THROUGH THE AFTERNOON...AND THE GFS IS ALSO ON
BOARD WITH THAT. DECIDED TO HOLD OFF ON THUNDERSTORM CHANCES OVER
THE NORTHERN COUNTIES UNTIL THIS EVENING WHEN DYNAMICS IMPROVE
WITH APPROACHING COLD FRONT. SPC ALSO HAS A SLIGHT RISK IN PLACE
FOR THE NORTHERN HALF OF OUR FORECAST AREA FOR DAY 1...BUT MAINLY
FOCUSING DURING THAT EVENING TIME FRAME AS WELL.
CURRENTLY...TEMPS ACROSS THE AREA ARE GENERALLY IN THE LOW 60S
WITH SOUTHEASTERLY WINDS OF 5 TO 10 MPH.
&&
.SHORT TERM /T0NIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 326 AM EDT TUE MAY 20 2014
THE MAIN FOCUS OF THE SHORT TERM PERIOD IS SEVERE THUNDERSTORM
THREAT IN ASSOCIATION WITH COLD FRONT. SPC CONTINUES TO KEEP ALL
OF CENTRAL INDIANA UNDER A SLIGHT RISK FOR DAY 2.
COLD FRONT IS EXPECTED TO ENTER A RATHER DESTABILIZED ENVIRONMENT
TOMORROW AFTERNOON. MLCAPES REMAIN IMPRESSIVE WITH SUBSTANTIAL
DAYTIME HEATING. LOW LEVEL MOISTURE REMAINS A BIT OVERDONE...BUT
SHOULD STILL BE SUFFICIENT. WESTERLY FLOW WILL BE CONSISTENT
THROUGH ALL LEVELS. THERE WILL BE A LACK OF DIRECTIONAL
SHEAR...BUT SPEED SHEAR WILL BE FAIRLY STRONG.
ACTIVITY WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST ON WEDNESDAY
EVENING AND THE REMAINDER OF SHORT TERM PERIOD WILL BE DRY. HIGHS
WILL FALL BACK INTO THE 70S FOR THURSDAY IN WAKE OF COLD FRONT.
STUCK WITH A MODEL BLEND FOR TEMPS THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MEMORIAL DAY/...
ISSUED AT 140 AM EDT TUE MAY 20 2014
MODELS AND REGIONAL BLEND IN GOOD AGREEMENT ON A DRY MEMORIAL DAY
WEEKEND...AND THIS LOOKS REASONABLE AS SURFACE HIGH PRESSURE BUILDS
IN FROM THE NORTHWEST ON FRIDAY AS AN UPPER LOW MOVES INTO THE
NORTHEASTERN STATES...AND AN UPPER RIDGE MOVES INTO THE PLAINS.
MODELS AND BLEND ALSO IN GOOD SHAPE ON TEMPERATURE TRENDS WITH COLD
ADVECTION AND 850 MILLIBAR TEMPERATURES FAVORING A SLIGHT COOL DOWN
COMPARED TO MIDWEEK WITH NEAR NORMAL AFTERNOON HIGHS IN THE LOWER TO
MID 70S LOOKING GOOD ON FRIDAY AND WARMING TO THE MID AND UPPER 70S
ON SUNDAY AND UPPER 70S AND MID 80S ON MEMORIAL DAY AS UPPER RIDGE
BUILDS IN FROM THE PLAINS AND SURFACE HIGH SHIFTS TO THE
SOUTHEASTERN STATES...WELL AHEAD OF A WESTERN FRONTAL SYSTEM.
&&
.AVIATION /DISCUSSION FOR 201200Z TAF ISSUANCE/...
ISSUED AT 627 AM EDT TUE MAY 20 2014
VFR CONDITIONS EXPECTED THROUGH AT LEAST 00Z ACROSS THE TERMINALS.
CU DEVELOPMENT PROGS SUGGEST DIURNAL CEILINGS AFTER 16Z TO GO WITH
THE AC OUT THERE NOW.
LAF...ESPECIALLY...AND PERHAPS IND...COULD SEE MVFR CONDITIONS IN
THUNDERSTORMS ALONG WITH HIGH THUNDERSTORM WINDS IF SEVERE SQUALL
LINE DEVELOPS LATE TODAY ACROSS EASTERN IOWA OR NORTHWESTERN
ILLINOIS PER THE STORM PREDICTION CENTER DAY 1 SEVERE WEATHER
OUTLOOK. FOR NOW...CONFIDENCE IN EXACT TIMING AND PATH OF SQUALL
LINE IS NOT GREAT. SO...WILL JUST THROW IN VCTS AT LAF AFTER 04Z AND
IND AFTER 06Z...AND FINE TUNE IN SUBSEQUENT TAFS. OTHERWISE...WILL
LEAVE THUNDER OUT TONIGHT AT HUF AND BMG...WITH BETTER CONFIDENCE.
WARM FRONT SHOULD BE NORTHEAST OF THE TERMINALS AT ISSUANCE TIME
WITH SOUTHWEST WINDS NEAR 15 KNOTS GUSTING TO NEAR 20 KNOTS BY 15Z
THIS MORNING. MEANWHILE...THE COLD FRONT WILL STILL BE NORTHWEST OF
LAF BY 12Z WEDNESDAY. SOUTHWEST WINDS WILL STILL NEAR 10 KNOTS
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD/CP
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
633 AM CDT TUE MAY 20 2014
.SHORT TERM /TODAY/...
ISSUED AT 332 AM CDT TUE MAY 20 2014
ISOLATED CENTRAL IA THUNDERSTORM APPROACHING SEVERE LIMITS
DISSIPATED QUICKLY LAST HOUR. RAP SOUNDINGS SEEMED TO REFLECT THE
ENVIRONMENT QUITE WELL WITH POTENTIAL FOR STORMS ROOTED NEAR THE
SURFACE SHORTLY AFTER MIDNIGHT...BUT MLCINH INCREASING QUICKLY AS
BOUNDARY LAYER COOLS FURTHER AND DECOUPLING FINALLY TAKING PLACE.
WITH THIS PROGRESSION DO NOT REALLY EXPECT ANY ADDITIONAL
DEVELOPMENT UNTIL PEAK HEATING OF THE AFTERNOON...WHICH IS THE
PRIMARY FORECAST CONCERN.
SCENARIO FOR TODAY HAS CHANGED LITTLE OVER THE PAST FEW DAYS WITH
SEVERE WEATHER POTENTIAL STILL CONDITIONAL. MODELS ALL DEPICT
SIMILAR THERMODYNAMIC ENVIRONMENT WITH MLCINH ERODING DURING THE
AFTERNOON AND MLCAPES TO AROUND 1500 J/KG. HOWEVER WHILE THE CINH
HAS DIMINISHED SUFFICIENTLY FOR CONVECTION TO FIRE...LIMITING
FACTORS INCLUDE WEAK CONVERGENCE AND THE FACT THAT WARM 1-3KM
TEMPS WILL KEEP PARCELS FROM REALLY ACCELERATING UNTIL REACHING
3KM OR HIGHER. THERE IS A QUESTION WHETHER THE WEAK CONVERGENCE
WILL OVERCOME THIS. LARGE SCALE FORCING MAY HELP LIFT AND
DESTABILIZATION OF 1-3KM LAYER TOWARD 00Z HOWEVER AS CURRENT
DAKOTAS MN JET SEGMENT MOVES EASTWARD. THUS STILL HAVE SCATTERED
THUNDERSTORMS DEVELOPING IN THE EASTERN HIGHWAY 30/I80/HIGHWAY 92
CORRIDORS. MAIN SEVERE THREATS STILL APPEAR TO BE LARGE HAIL OR
WIND. LOW LEVEL SHEAR FAIRLY WEAK WITH HIGHER LCLS. STORM MOTION
WILL BE FAIRLY SLOW TOO BASED ON MEAN WIND AND BUNKERS
MOTION...LIKELY UNDER 25KTS.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 332 AM CDT TUE MAY 20 2014
THE SURFACE TROUGH SERVING AS A FOCUS FOR THUNDERSTORM DEVELOPMENT
THIS AFTERNOON...AS DISCUSSED IN THE SHORT TERM SECTION
ABOVE...WILL MOVE SOUTH OUT OF THE AREA TONIGHT WITH DECREASING
POPS OVERNIGHT. THEREAFTER...THE BOUNDARY WILL REMAIN OVER
MISSOURI WITH A LARGE SURFACE HIGH PRESSURE AREA BUILDING OVER
IOWA AND THE UPPER MIDWEST FOR SEVERAL DAYS. THIS WILL KEEP
TEMPERATURES RELATIVELY COOL TOWARD THURSDAY AND FRIDAY WITH RAIN
CHANCES REMAINING OVER MISSOURI OR POSSIBLY AFFECTING THE FAR
SOUTHERN FRINGE OF IOWA AT TIMES.
MEANWHILE...AT 500 MB A LARGE CUTOFF LOW WILL DEVELOP OVER THE
FAR SOUTHWEST U.S. LATE THIS WEEK AND RESIDE SOMEWHERE AROUND THE
CALIFORNIA/ARIZONA BORDER BY FRIDAY MORNING. THIS WILL SQUEEZE A
500 MB RIDGE DOWNSTREAM ACROSS THE CENTRAL U.S. AND UP TOWARD
IOWA. AS THE CUTOFF LOW SLOWLY MOVES EASTWARD THIS CENTRAL U.S.
RIDGE WILL STEADILY ERODE...ALLOWING THE UPPER MIDWEST SURFACE
RIDGE TO SLIDE EASTWARD WITH A RETURN OF SOUTHEAST SURFACE FLOW
OVER IOWA AND THE OLD FRONTAL BOUNDARY MOVING BACK OVERHEAD. THIS
WILL RESULT IN RAIN CHANCES RETURNING TO THE FORECAST AREA THIS
WEEKEND AND INTO EARLY NEXT WEEK...PERSISTING FOR MULTIPLE DAYS AS
THE 500 MB LOW MOVES INTO THE AREA THROUGH THE END OF THE SEVEN
DAY FORECAST PERIOD. CONSEQUENTLY FROM SATURDAY ONWARD GENERALLY
30 TO 40 POPS ARE CARRIED IN EVERY PERIOD WITH GRADUALLY
INCREASING TEMPERATURES.
&&
.AVIATION...20/12Z
ISSUED AT 633 AM CDT TUE MAY 20 2014
LIFR/IFR FOG CONDITIONS ARE IN PLACE ACROSS PORTIONS OF NRN IA
EARLY THIS MORNING BUT HAVE YET TO AFFECT TAFS SITES OUTSIDE OF
MVFR BRUSHING KFOD/KMCW. AFTER MORNING FOG DISSIPATES ATTENTION
WILL TURN TOWARD CONVECTIVE DEVELOPMENT ALONG CURRENT WEAK FRONTAL
BOUNDARY NOTED FROM KOMA AREA TO NEAR KMCW AT 12Z. FRONT WILL
LIKELY TRIGGER THUNDERSTORMS WITH LIMITED COVERAGE ACROSS CENTRAL
IA 21Z-00Z AS IT DRIFTS SOUTH THEN LASTING INTO THE EARLY EVENING
BEFORE DISSIPATING WITH LOSS OF SUN. LIMITED COVERAGE WILL MAKE
TIMING AND LOCATIONS UNCERTAIN ENOUGH THAT HAVE STARTED WITH VCSH
WORDING AND NO THUNDER AS OF YET...ALTHOUGH IT WOULD BE LIKELY AT
ANY SITES THAT DO SEE PRECIP. MAINLY VFR OVERNIGHT ALTHOUGH PATCHY
FOG POSSIBLE...ESPECIALLY SOUTH /KOTM/ IN CLOSER PROXIMITY TO
DIFFUSE FRONT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS JACKSON KY
1100 AM EDT TUE MAY 20 2014
.UPDATE...
ISSUED AT 1100 AM EDT TUE MAY 20 2014
EXCEPT FOR A FEW MINOR EDITS...THE FORECAST APPEARS ON TRACK TODAY.
NOTICE A FEW ECHOES ON RADAR NEAR CVG ASSOCIATED WITH THE WEAK WARM
FRONT MOVING ACROSS THE REGION AT THIS TIME. NEAR TERM MODEL
GUIDANCE INCLUDING LATEST HRRR KEEPS ANY SHOWER ACTIVITY JUST TO OUR
NORTH SO WILL MONITOR UPSTREAM DEVELOPMENTS CLOSELY BUT MAINTAIN A
DRY FORECAST FOR THE REST OF THE DAY AT THIS TIME.
UPDATE ISSUED AT 726 AM EDT TUE MAY 20 2014
MADE A FEW TWEAKS TO THE CLOUD COVER FORECAST FOR THE REST OF TODAY
INTO EARLY THIS EVENING. SATELLITE IMAGERY AND DIRECT OBSERVATION
REVEALED THAT CLOUDS ARE A BIT MORE EXTENSIVE ACROSS EASTERN KENTUCKY
THAN THE FORECAST HAD BEEN REFLECTING. INCREASED CLOUD COVER ACROSS
THE AREA THROUGH EARLY THIS EVENING TO ACCOUNT FOR THIS. ALSO
INGESTED THE LATEST OBS DATA TO ESTABLISH NEW TRENDS IN HOURLY
TEMPERATURES AND WINDS FOR TODAY. THE REST OF THE FORECAST WAS IN
GOOD SHAPE WITH NO OTHER CHANGES NEEDED. THE ZONE FORECAST TEXT
PRODUCT WAS ALSO GOOD AS IS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 323 AM EDT TUE MAY 20 2014
THE MODELS IN GENERAL WERE IN PRETTY GOOD AGREEMENT IN THE SHORT
TERM. THE OVERALL CONSENSUS IS FOR A RIDGE OF HIGH PRESSURE TO REMAIN
IN PLACE TODAY AND TONIGHT...BRINGING WARM AND DRY WEATHER TO THE
REGION. THE RIDGE WILL BEGIN TO BREAK DOWN AND MOVE OFF TO THE SOUTH
LATE IN THE DAY ON WEDNESDAY...AS A COLD FRONT PUSHES SOUTHWARD OUT
OF THE OHIO VALLEY AHEAD OF A SOUTHWARD MOVING RIDGE OF CANADIAN HIGH
PRESSURE. SHOWERS AND STORMS WILL BEGIN TO BREAK OUT ALONG THE FRONT
LATE WEDNESDAY MORNING AS THE FRONT FIRST BEGINS TO MOVE INTO THE
AREA. THESE SHOWERS AND STORMS WILL BECOME MORE NUMEROUS DURING THE
AFTERNOON AND EVENING HOURS DURING PEAK HEATING AS THE FRONT MOVES
ACROSS THE AREA. THE LATEST MODEL SOUNDINGS...PARTICULARLY THE
NAM12...ARE SHOWING A PERIOD OF PRETTY GOOD INSTABILITY ACROSS THE
AREA WEDNESDAY AFTERNOON. WITH THE FRONT MOVING THROUGH DURING THIS
TIME...AND WITH SOME DECENT MOISTURE OFF THE GULF OF MEXICO ALREADY
OVER THE AREA...SOME OF THE STORMS ON WEDNESDAY COULD APPROACH SEVERE
LIMITS...WITH DAMAGING WINDS BEING THE MAIN THREAT.
TEMPERATURES DURING THE PERIOD WILL BE RUNNING A GOOD DEAL ABOVE
NORMAL...WITH HIGHS TODAY AND TOMORROW LIKELY TOPPING OUT IN THE 80S
PRETTY MUCH EVERYWHERE. OVERNIGHT LOWS WILL ONLY MAKE INTO THE LOWER
60S FOR MOST FOLKS...AS GOOD MOISTURE RETURN OFF THE GULF KEEP THE
AIR MOIST ENOUGH TO NOT ALLOW FOR THE TYPES OF TEMPERATURE DROPS WE
HAVE EXPERIENCED THE PAST FEW NIGHTS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM EDT TUE MAY 20 2014
THE MODELS ARE IN GOOD AGREEMENT WITH A BLOCKY LONG WAVE PATTERN
ACROSS THE CONUS THROUGH THE EXTENDED. A CA/NV UPPER LEVEL LOW WILL
SLOWLY MOVE EAST INTO THE PLAINS...WHILE A TROUGH BECOMES REINFORCED
OFF OF THE EASTERN SEABOARD. A RIDGE AXIS WILL BE SANDWICHED IN
BETWEEN THE TWO TROUGHS...SLOWLY SHIFTING FROM THE PLAINS TO THE
MISSISSIPPI VALLEY THROUGH THE PERIOD.
WEDNESDAY NIGHT WILL START OUT A BIT STORMY ACROSS THE AREA...AS A
COLD FRONT SAGS SOUTHWARD TOWARDS EASTERN KENTUCKY ALONG WITH A PASSING
SHORT WAVE TROUGH IN UPPER LEVEL NORTHWEST FLOW. MCS ACTIVITY APPEARS
LIKELY SOMEWHERE IN THE OHIO VALLEY...WITH AN ONGOING SEVERE WEATHER
THREAT LINGERING INTO AT LEAST THE FIRST PART OF THE NIGHT.
THE BOUNDARY WILL CONTINUE TO SAG SOUTH DURING THE DAY ON
THURSDAY...ALTHOUGH INSTABILITY WILL NOT BE AS STOUT...SO ANY
SCATTERED CONVECTION SHOULD BE MORE TAME DURING THE AFTERNOON. ONCE
THE STORMS WANE THROUGH THE EVENING...DRY WEATHER IS EXPECTED TO
ENSUE THEREAFTER...AS THE UPPER LEVEL RIDGE AXIS GRADUALLY SHIFTS
OVERHEAD THROUGH EARLY NEXT WEEK.
HIGHS ON THURSDAY WILL TOP OUT NEAR 80...BEFORE COOLING OFF TO THE
MID AND UPPER 70S BEHIND THE FRONT ON FRIDAY AND SATURDAY. HIGHS WILL
THEN WARM THROUGH EARLY NEXT WEEK...REACHING THE LOW TO MID 80S BY
MONDAY. LOWS WILL AVERAGE IN THE 50S...ALTHOUGH A FEW SHELTERED
VALLEYS MAY GET DOWN INTO THE UPPER 40S FRIDAY AND SATURDAY NIGHTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 726 AM EDT TUE MAY 20 2014
VFR CONDITIONS WILL PERSIST THROUGH THE ENTIRE FORECAST PERIOD AS
HIGH PRESSURE GIVES WAY TO THE PASSAGE OF A WEAK...MOISTURE STARVED
WARM FRONT THIS MORNING. THE MAIN IMPACT FOR AVIATION OVER THE NEXT
24 HOURS WILL BE AN INCREASE IN SOUTH TO SOUTHWEST WINDS BEHIND THE
FRONT EARLY TODAY...ESPECIALLY FOR LOZ AND SME WHERE GUSTS TO
AROUND 20 KTS ARE EXPECTED BY MIDDAY. SCATTERED TO BROKEN MID AND
HIGH LEVEL CLOUDS HAVE ALREADY BEGUN AFFECTING THE TAF SITES THIS
MORNING. THE MID LEVEL CLOUDS ARE DOMINANT AT THE MOMENT...WITH BKN
CIGS OF 7-10K OCCURRING. THE CLOUDS ARE EXPECTED TO LOWER A BIT AS
THE MORNING PROGRESSES...WHICH CAN BE SEEN IN UPSTREAM OBS. THE OTHER
ISSUE OF NOTE FOR AVIATORS TODAY WILL BE THE WINDS. SOUTH TO
SOUTHWEST WINDS ARE EXPECTED TO PICK UP AS THE SUN CLIMBS THE EARLY
MORNING SKY. SUSTAINED SPEEDS OF 10 TO 15 MPH ARE EXPECTED WITH GUSTS
OF UP TO 20 MPH POSSIBLE BY THIS AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR/ABE
SHORT TERM...AR
LONG TERM...GEOGERIAN
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
744 AM EDT TUE MAY 20 2014
LATEST UPDATE...
UPDATE/AVIATION
.SYNOPSIS...
ISSUED AT 326 AM EDT TUE MAY 20 2014
AFTER A FEW MORNING SHOWERS MOST OF THE REMAINDER OF THE DAY WILL BE
DRY TODAY. HOWEVER AROUND ROUND OF SHOWERS AND STORMS CAN BE
EXPECTED TOWARD EVENING...ESPECIALLY TOWARD I-94. THE EVENING
STORMS COULD BE STRONG TO SEVERE. THE PRECIPITATION MAY LINGER INTO
WEDNESDAY MORNING...BEFORE COMING TO AN END BY MID DAY. QUIETER
WEATHER IS EXPECTED INTO WEDNESDAY NIGHT AND THURSDAY. DAYTIME
TEMPERATURES WILL MAINLY BE IN THE 70S TODAY AND WEDNESDAY BEFORE
COOLING INTO THE 60S FOR THURSDAY.
MILD WEATHER SHOULD CONTINUE INTO THE HOLIDAY WEEKEND WITH HIGHS
MAINLY IN THE 70S TO AROUND 80. THERE COULD BE WIDELY SCATTERED
STORMS TOWARD THE END OF THE HOLIDAY...SUNDAY NIGHT AND MEMORIAL DAY.
&&
.UPDATE...
ISSUED AT 744 AM EDT TUE MAY 20 2014
BASED ON THE LATEST RAP MODEL DATA AND SATELLITE AND RADAR TRENDS
I INCREASED THE HIGH TEMPERATURE ABOUT 5 DEGREES ACROSS MOST OF
THE CWA. I ALSO ADDED MORE DETAIL TO THE TIMING OF THE SHOWERS
EXITING THE AREA THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 326 AM EDT TUE MAY 20 2014
PCPN OUT AHEAD OF A VORT MAX WILL CONTINUE TO TRAVERSE THE CWA EARLY
THIS MORNING. HOWEVER THE VORT WILL BE MOVING OFF TO THE EAST BY
LATE MORNING TAKING THE PCPN WITH IT. EXPECT A LULL THROUGH THE
MIDDLE PART OF THE DAY. SUBSIDENCE SHOULD TRY TO ERODE SOME OF THE
CLOUDS INTO THE AFTERNOON...SO WENT A LITTLE HIGHER WITH MAX TEMPS
WITH THE ADDED SUNSHINE.
ANOTHER RATHER SMALL VORT MAX WAS CROSSING EASTERN NEBRASKA EARLY
THIS MORNING. THE MODELS HAVE BEEN KEYING IN ON THIS FEATURE OVER
THE PAST SEVERAL RUNS...BLOWING UP AN MCS OUT AHEAD OF IT. THIS
WILL BRING A RETURN RISK OF SHOWERS AND STORMS LATE IN THE DAY OR
INTO THE EVENING. WITH ENOUGH SUNSHINE WE WILL SEE INSTABILITY
CLIMB...PARTICULARLY ALONG I-96 AND SOUTH. SBCAPES VALUES CLIMB TO
AROUND 2K J/KG ALONG I-94. THE NORTH COULD STAY A BIT MORE STABLE
WITH A WARM FRONT AND MORE CLOUD COVER HANGING OVER THIS AREA. SPC
HAS PUT THE AREA SOUTH OF I-96 IN THE SLIGHT RISK FOR SEVERE
STORMS. CAN NOT DISAGREE WITH THIS WITH 0-6KM BULK SHEAR VALUES
AROUND 40KTS SUGGESTING ORGANIZED STORMS WITH STRONG UPDRAFTS.
HOWEVER...I AM CONCERN WITH HOW SMALL THIS VORT/SHORT WAVE IS AND A
WOBBLE TO THE SOUTH MAY CAUSE MUCH OF THE MCS TO MISS US. IT DOES
SEEM THERE IS A BE HIGHER POTENTIAL TO OUR SOUTH...MORE TOWARD
I-80. HAVE MAINTAINED LIKELY POPS FOR SHOWERS AND STORMS SOUTH OF
I-96...AS THERE DOES APPEAR TO BE BETTER MOISTURE POOLING ALONG THE
WARM FRONT LATE TONIGHT AND SOME AREAS COULD SEE AROUND A HALF INCH
OF RAIN... I/M JUST NOT CONVINCED WE WILL SEE SEVERE STORMS.
A WEAK COLD FRONT SLIDES ACROSS THE CWA WEDNESDAY MORNING TAKING THE
SHOWERS AND STORMS WITH IT. HAVE POPS IN FOR THE FIRST HALF OF THE
DAY...BUT WE WILL BE DRYING OUT BY AFTERNOON.
WEDNESDAY NIGHT AND THURSDAY WILL BE DRY. AN UPPER LOW WILL BE OVER
EASTERN ONTARIO WHICH WILL PULL IN COOLER AIR AND PROBABLY A BROKEN
CU/SC DECK INTO THURSDAY. THIS SHOULD HOLD DAYTIME TEMPS IN THE 60S.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 326 AM EDT TUE MAY 20 2014
WITH THE MEMORIAL DAY WEEKEND BEING THIS WEEKEND... THAT OF COURSE
WOULD BE THE FOCUS FOR THIS DISCUSSION. AS WE HAVE SUGGESTED FOR THE
LAST FEW DISCUSSIONS... MOSTLY CLEAR SKIES... LIGHT WINDS AND
TEMPERATURES BEING ABOVE NORMAL IS WHAT WE ARE EXPECTING. A GREAT
WEEKEND TO BE OUTDOORS IN SOUTHWEST LOWER MICHIGAN.
THE LONG RANGE FORECAST MODELS HAVE BEEN AND CONTINUE TO BE IN GOOD
AGREEMENT WITH AN UPPER RIDGE DEVELOPING OVER THE WESTERN GREAT
LAKES AND CENTRAL PLAINS BY EARLY IN THE WEEKEND THEN HOLDING FAST
THROUGH AT LEAST THE MIDDLE OF THE FOLLOWING WEEK. THIS WOULD BE A
DRY WEATHER PATTERN FOR SOUTHWEST MICHIGAN AND AN INCREASINGLY WARM
ONE. WITH 850 MB TEMPERATURES REACHING THE MID TEENS CENTIGRADE BY
MONDAY... HIGHS COULD BE WELL UP INTO THE 80S. ONCE AGAIN AS LIKE
YESTERDAY OUR FORECAST HIGHS ARE CONSERVATIVE...MOSTLY SINCE THIS IS
FOR 5 TO 7 DAYS OUT IN TIME.
THE ONLY ISSUE LATE IN THE PERIOD IS AN EJECTING UPPER LOW FROM THE
SOUTHWEST CONUS THAT WOULD BRING THE THREAT OF CONVECTION JUST
BEHIND THIS FORECAST PERIOD.
THE BOTTOM LINE IS DRY WARM WEATHER SAT THROUGH MON WITH HIGHS AND
LOWS INCREASING A FEW DEGREES EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 744 AM EDT TUE MAY 20 2014
THE SHOWERS ARE CURRENTLY MOVING OUT OF THE AREA. I EXPECT VFR
CIGS THROUGH MOST OF THE DAYLIGHT HOURS WITH LITTLE IN THE WAY OF
CONVECTION. HOWEVER TONIGHT I EXPECT AN AREA OF THUNDERSTORMS TO
CROSS THE SOUTHWEST SECTIONS OF THE AREA. BEING SO FAR OUT IN TIME
DID NOT PUT DETAILS OF THIS IN THE TAFS. SOME OF THE THUNDERSTORMS
COULD BE STRONG TO SEVERE... IF THEY IMPACTED ANY OF THE TAF
SITES... THE I-94 TAF SITES WOULD BE THE MOST LIKELY TO SEE THESE
STORMS.
&&
.MARINE...
ISSUED AT 326 AM EDT TUE MAY 20 2014
DECIDE TO ISSUE A SMALL CRAFT ADVISORY FOR THE POINTS REGION UNTIL
MID DAY TODAY. BRISK SSE WINDS WILL HOLD AROUND 20 KNOTS THIS
MORNING...THEN DROP OFF INTO THE AFTERNOON. WAVES WILL BE THE
HIGHEST A COUPLE MILES OFFSHORE...INTO THE 3 TO 5 FOOT RANGE THIS
MORNING.
INTO THE AFTERNOON WINDS WILL DROP TO AROUND 10 KNOTS AND THE WAVES
SHOULD SUBSIDE. THE LAKE SHOULD BECOME CHOPPY AGAIN WEDNESDAY
AFTERNOON AS WE GET INTO COLD ADVECTION BEHIND A COLD FRONT. BUT AT
THIS POINT IT LOOKS LIKE WE WILL STAY BELOW SMALL CRAFT CRITERIA.
&&
.HYDROLOGY...
ISSUED AT 328 PM EDT MON MAY 19 2014
RIVERS ARE CONTINUING TO RUN HIGH ACROSS THE GRAND RIVER BASIN
ALTHOUGH MOST LOCATIONS HAVE CRESTED DUE TO RECENT RAINS. THE LAST
PLACES TO CREST WILL BE FROM GRAND RAPIDS WEST TO THE LAKESHORE.
SOME LOCALLY HEAVY RAINS ARE POSSIBLE TUESDAY NIGHT ALONG A COLD
FRONT BUT BASIN AVERAGE RAIN SHOULD BE LESS THAN AN INCH AND
SHOULD NOT BE ENOUGH TO CAUSE SIGNIFICANT RISES ON THE MAINSTEM
RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LMZ848-
849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...OSTUNO
MARINE...JK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
957 AM CDT TUE MAY 20 2014
.UPDATE...
ISSUED AT 947 AM CDT TUE MAY 20 2014
VERY WEAK FRONT HAS SETTLED ALONG INTERSTATE 80 AND WILL CONTINUE
TO DRIFT SLOWLY SOUTH THROUGH THE REMAINDER OF THE DAY. 12Z UPPER
AIR ANALYSIS REVEALED 20 TO 40 METER HEIGHT RISES ACROSS THE
PLAINS...WITH AN 300 MB JET WELL NORTH OF THE AREA ACROSS THE
NORTHERN PLAINS INTO THE WESTERN GREAT LAKES REGION. 700MB TEMPS
SOUTH OF THE BOUNDARY WERE ALSO QUITE WARM FROM +12 TO +14.
ENTRANCE REGION OF THE UPPER JET MAY HELP TO IGNITE THUNDERSTORMS
NORTH OF THE BOUNDARY...BUT MAINLY ACROSS IOWA TODAY...BUT THEY
COULD ALSO DEVELOP AS FAR WEST AS THE OMAHA AREA BY 20-21Z...BUT
WILL ALSO BE FIGHTING A CAP. NOT SURE THEY COULD BACKBUILD FAR
ENOUGH TO THE LINCOLN AREA...THUS HAVE REMOVED THE SLIGHT CHANCE
POPS THAT FAR SOUTHWEST.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
WV IMAGERY THIS MORNING SHOWING POS TILT LONGWAVE TROF EXTENDING
FROM CNTRL CANADA TO THE WEST COAST WITH TWO DISTINCT CLOSED
CIRCULATIONS SEEN...ONE CENTERED OVER S-CNTRL CANADA AND THE OTHER
OF THE NRN CA COASTLINE. SATL PIX ALSO REVEALING MOVEMENT MOVEMENT OF
THIS FEATURE HAS BEEN MINIMAL THE LAST SEVERAL HOURS....BUT MODELS
IN GOOD AGREEMENT WEST COAST CIRCULATION WILL GRADUALLY BECOME CUT
OFF FROM MAIN FLOW BY THE TIME IT REACHES THE SWRN CONUS LATER THIS
WEEK.
MEANWHILE...DISTINCT SFC THERMAL BNDRY WAS SITUATED FROM NRN IA TO S-
CNTRL NEB TO WRN KS WITH LLVL MOISTURE ADV SPREADING NWD THRU OK/KS
AND INTO THE SRN CWA. OUT WEST...SMALL AREA OF ELEVATED CONVECTION
WAS SITUATED WITHIN AREA OF 700MB QG FRONTOGENESIS/MODEST BNDRY LYR
CONVG. LATEST HRRR IS SUGGESTING ACTIVITY WILL BE SHORT LIVED AS
ENVIRONMENT BECOMES MORE STABLE IN THE NEXT COUPLE COUPLE HOURS.
LATEST MODELS CONFIRM GOING FCST IS IN PRETTY GOOD SHAPE ADVERTISING
CONVECTIVE ACTIVITY LATER THIS WEEK...PARTICULARLY OVER WESTERN
SECTIONS OF THE CWA. AS AFOREMENTIONED UPPER LOW BECOMES CUT
OFF...FLOW ALOFT OVER THE CNTRL PLAINS WILL BECOME LESS PROGRESSIVE
AND ALLOW MID LYR FRONTOGENETIC FORCING ORIENTED NW-SE TO REMAIN
INVOF THE WRN CWA. THAT ALONG WITH RELATIVELY STRONG BNDRY LYR THETA-
E CONVG SHOULD ALLOW FOR TSTMS CHANCES BEGINNING LATE WED AFTN ALL
THE WAY INTO LATE THURSDAY NIGHT. AMPLE ENVIRONMENTAL MOISTURE WILL
BE ON TAP...PWS 1.75"/KI 35-40...THUS POTENTIAL FOR GENEROUS
RAINFALL AMOUNTS APPEAR TO BE RELATIVELY HIGH.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
MODELS CONTINUE TO ADVERTISE WRN CIRCULATION WILL BE QUITE SO
MIGRATING EWD THRU THE EXTENDED PDS..ALLOWING FOR CONTINUOUS SLY
LLVL MOIST ADV INTO THE CNTRL PLAINS. WITH INSTABILITY/MOISTURE AXIS
REMAINING INVOF THE CWA...WILL CARRY POPS THRU NEXT WEEKEND AND INTO
EARLY NEXT WEEK. IN ADDITION...COMPOSITE PARAMETERS SUGGEST SVR
THREAT IS MINIMAL AT BEST.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 603 AM CDT TUE MAY 20 2014
VFR CONDITIONS ARE EXPECTED AT TAF SITES THROUGH 21/12Z. A WEAK
FRONT PUSHING ACROSS KOMA/KLNK AT 11Z SHOULD CONTINUE INTO FAR
SERN NEBR/SWRN IA BY LATE AFTN. ALTHOUGH TSTMS COULD DEVELOP NEAR
THIS BOUNDARY LATER THIS AFTN...THE ACTIVITY SHOULD BE MOSTLY E OR
SE OF KLNK/KOMA AND THUS NO TSTM WAS MENTIONED.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...DEWALD
SHORT TERM...DEE
LONG TERM...DEE
AVIATION...CHERMOK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
605 AM CDT TUE MAY 20 2014
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
WV IMAGERY THIS MORNING SHOWING POS TILT LONGWAVE TROF EXTENDING
FROM CNTRL CANADA TO THE WEST COAST WITH TWO DISTINCT CLOSED
CIRCULATIONS SEEN...ONE CENTERED OVER S-CNTRL CANADA AND THE OTHER
OF THE NRN CA COASTLINE. SATL PIX ALSO REVEALING MOVEMENT MOVEMENT OF
THIS FEATURE HAS BEEN MINIMAL THE LAST SEVERAL HOURS....BUT MODELS
IN GOOD AGREEMENT WEST COAST CIRCULATION WILL GRADUALLY BECOME CUT
OFF FROM MAIN FLOW BY THE TIME IT REACHES THE SWRN CONUS LATER THIS
WEEK.
MEANWHILE...DISTINCT SFC THERMAL BNDRY WAS SITUATED FROM NRN IA TO S-
CNTRL NEB TO WRN KS WITH LLVL MOISTURE ADV SPREADING NWD THRU OK/KS
AND INTO THE SRN CWA. OUT WEST...SMALL AREA OF ELEVATED CONVECTION
WAS SITUATED WITHIN AREA OF 700MB QG FRONTOGENESIS/MODEST BNDRY LYR
CONVG. LATEST HRRR IS SUGGESTING ACTIVITY WILL BE SHORT LIVED AS
ENVIRONMENT BECOMES MORE STABLE IN THE NEXT COUPLE COUPLE HOURS.
LATEST MODELS CONFIRM GOING FCST IS IN PRETTY GOOD SHAPE ADVERTISING
CONVECTIVE ACTIVITY LATER THIS WEEK...PARTICULARLY OVER WESTERN
SECTIONS OF THE CWA. AS AFOREMENTIONED UPPER LOW BECOMES CUT
OFF...FLOW ALOFT OVER THE CNTRL PLAINS WILL BECOME LESS PROGRESSIVE
AND ALLOW MID LYR FRONTOGENETIC FORCING ORIENTED NW-SE TO REMAIN
INVOF THE WRN CWA. THAT ALONG WITH RELATIVELY STRONG BNDRY LYR THETA-
E CONVG SHOULD ALLOW FOR TSTMS CHANCES BEGINNING LATE WED AFTN ALL
THE WAY INTO LATE THURSDAY NIGHT. AMPLE ENVIRONMENTAL MOISTURE WILL
BE ON TAP...PWS 1.75"/KI 35-40...THUS POTENTIAL FOR GENEROUS
RAINFALL AMOUNTS APPEAR TO BE RELATIVELY HIGH.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
MODELS CONTINUE TO ADVERTISE WRN CIRCULATION WILL BE QUITE SO
MIGRATING EWD THRU THE EXTENDED PDS..ALLOWING FOR CONTINUOUS SLY
LLVL MOIST ADV INTO THE CNTRL PLAINS. WITH INSTABILITY/MOISTURE AXIS
REMAINING INVOF THE CWA...WILL CARRY POPS THRU NEXT WEEKEND AND INTO
EARLY NEXT WEEK. IN ADDITION...COMPOSITE PARAMETERS SUGGEST SVR
THREAT IS MINIMAL AT BEST.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 603 AM CDT TUE MAY 20 2014
VFR CONDITIONS ARE EXPECTED AT TAF SITES THROUGH 21/12Z. A WEAK
FRONT PUSHING ACROSS KOMA/KLNK AT 11Z SHOULD CONTINUE INTO FAR
SERN NEBR/SWRN IA BY LATE AFTN. ALTHOUGH TSTMS COULD DEVELOP NEAR
THIS BOUNDARY LATER THIS AFTN...THE ACTIVITY SHOULD BE MOSTLY E OR
SE OF KLNK/KOMA AND THUS NO TSTM WAS MENTIONED.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE
LONG TERM...DEE
AVIATION...CHERMOK
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
933 AM EDT TUE MAY 20 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL MOVE SOUTH OF THE AREA THIS
AFTERNOON AND TONIGHT. A WARM FRONT WILL MOVE ACROSS NORTH OF THE
AREA LATE TONIGHT...FOLLOWED BY A WEAK TROUGH WEDNESDAY NIGHT. A
STRONGER COLD FRONT WILL PUSH THROUGH THURSDAY NIGHT THEN STALL TO
THE SOUTH FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 930 AM TUESDAY...LATEST SATELLITE IMAGERY SHOWING CLOUDS
INCREASING OVER THE FAR NORTHWESTERN CWA AS A WEAK PIECE OF MID-
LEVEL ENERGY DIVES SOUTHEAST ACROSS KENTUCKY AND VIRGINIA. AT THE
SURFACE...RIDGE SHOULD SHIFT OFFSHORE IN THE AFTERNOON WITH LOW
LEVEL FLOW BECOMING SW AND INCREASING BY LATE IN THE AFTERNOON. AS
FOR THE CURRENT FORECAST...LITTLE CHANGE REQUIRED AS HIGH
TEMPERATURES WILL RANGE FROM THE LOW 80S INLAND TO MID 70S COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
AS OF 330 AM TUESDAY...LATEST MODELS CONTINUE TO INDICATE SLIGHT CHC
OF SHOWERS AND PSBLY TSTMS OVER NE SECTIONS LATE TONIGHT AS WARM
FRONT MOVES ACROSS JUST N OF AREA...THUS NO CHANGE TO PREVIOUS FCST
POPS. REST OF AREA WILL SEE SOME INCREASE IN CLOUDINESS OVERNIGHT
WITH SW BREEZE KEEPING TEMPS IN UPR 50S TO MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 230 AM TUE...UPPER FLOW WILL BE NORTHWEST THROUGH THE EXTENDED
PERIOD. AT THE SURFACE A PREFRONTAL TROF WILL MOVE SOUTHEAST ACROSS
THE AREA WEDNESDAY NIGHT. TAPERED POPS FROM LOW CHANCE NORTHEAST TO
DRY SOUTHWEST. CONTINUE LOW CHANCE POPS ON THURSDAY AFTERNOON AHEAD
OF THE COLD FRONT APPROACHING FROM THE NORTHWEST. THE FRONT PASSES
THROUGH THURSDAY NIGHT AND WILL BE WELL SOUTH OF HERE FRIDAY
MORNING. REMAINDER OF THE PERIOD WILL BE DRY WITH A SURFACE RIDGE
BUILDING INTO THE REGION FROM THE NORTHWEST.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH 12Z WEDNESDAY/...
AS OF 655 AM TUESDAY...VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
SOME HIGH CLOUDS WILL INCREASE WITH NW FLOW ALOFT TODAY WITH SOME
SCU AND AC PSBL TONIGHT WITH WARM FRONT MOVING ACROSS TO N. SCT
CONVECTIVE THREAT OVER NE SECTIONS 06Z-12Z TONIGHT BUT EXPECTED TO
REMAIN N AND E OF TAF SITES AT THIS TIME. SW WINDS TO AROUND 10 KT
WILL DEVELOP BY AFTN AND CONTINUE THROUGH TONIGHT.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 AM TUE...VFR THROUGH THE PERIOD. ISOLATED CONVECTION
POSSIBLE WEDNESDAY NIGHT MAINLY AT PGV AND EWN. DRY CONDITIONS
FORECAST FOR ISO AND OAJ. ISOLATED TO SCATTERED CONVECTION POSSIBLE
THURSDAY AT ALL SITES AHEAD OF A COLD FRONT APPROACHING FROM THE
NORTHWEST. THE FRONT WILL PASS THROUGH THURSDAY NIGHT WITH DRY
WEATHER INTO THE WEEKEND AS HIGH PRESSURE BUILDS INTO THE AREA FROM
THE NORTHWEST.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 935 AM TUESDAY...AS SURFACE RIDGE MOVES OFFSHORE...SOUTHWEST
FLOW WILL INCREASE THIS AFTERNOON WITH 15 TO 20 KNOT WINDS LIKELY
BY LATE IN THE DAY PER LATEST RAP MODEL. SPEEDS WILL REMAIN NEAR
15-20 KT OVERNIGHT WITH TIGHTENING PRES GRADIENT AS WARM FRONT
MOVES ACROSS TO N.
NWPS IN BETTER AGREEMENT WITH WW3 THIS MORNING...AND BLEND WITH
PREVIOUS FCST USED FOR THIS PACKAGE. HEIGHTS MAINLY 2-4 INTO THIS
EVENING BUILDING TO 3-5 FT OVERNIGHT.
LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 230 AM TUE...SOUTHWEST FLOW WEDNESDAY AND WEDNESDAY NIGHT
ACROSS THE MARINE ZONES. SMALL CRAFT WINDS/SEAS FORECAST FOR THE
COASTAL WATERS SOUTH OF OREGON INLET. THE PRESSURE GRADIENT WILL
LOOSEN THURSDAY AND WINDS WILL VEER TO WEST IN ADVANCE OF THE COLD
FRONT APPROACHING FROM THE NORTHWEST WITH WINDS AND SEAS SUBSIDING.
THE FRONT PASSES THROUGH THURSDAY NIGHT AND WINDS WILL VEER FURTHER
TO NORTHWEST. LIGHT WINDS AND SEAS FORECAST FRIDAY INTO SATURDAY
WITH A RIDGE OF HIGH PRESSURE BUILDING INTO THE REGION FROM THE
NORTHWEST.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...CTC
SHORT TERM...JBM
LONG TERM...HSA
AVIATION...JBM/HSA
MARINE...JBM/CTC/HSA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1052 AM MDT TUE MAY 20 2014
.UPDATE...
ISSUED AT 1050 AM MDT TUE MAY 20 2014
STABLE MOIST AIR AND AREAS OF STRATUS/STRATOCUMULUS COVERING THE
NORTHEAST PLAINS AT THIS HOUR IN THE WAKE OF A PSEUDO COLD FRONT/
T-STORM OUTFLOW BOUNDARY THAT BLEW DOWN FROM STRONG T-STORMS
CROSSING THE NORTHEAST CORNER OF THE STATE LAST NIGHT. BOUNDARY
LAYER IS PRESENTLY STRONGLY CAPPED AND LOW AND MID-LEVELS LAPSE
RATES ARE ABSOLUTE TO CONDITIONALLY STABLE. ABOVE THE SFC BASED
INVERSION...EAST FACING SLOPES ARE HEATING UP WITH MODELS
INDICATING SFC-650 MB LAPSES RATES IN THE 8-9DEG/KM BY EARLY THIS
AFTERNOON. MEANWHILE LIGHT EASTERLY LOW-LEVEL UPSLOPE FLOW PRESENT
ON THE PLAINS AND UP INTO THE LOWER FOOTHILLS.
LATER TODAY...ISOLATED/SCATTERED SHOWERS/T-STORMS EXPECTED TO
FORM INITIALLY OVER THE FRONT RANGE AND HIGHER REACHES OF THE
MOSQUITO AND PARK RANGES. BUT ITS THOSE STORMS CLOSER TO THE HIGH
PLAINS MOISTURE THAT SHOULD SUSTAIN THEIR UPDRAFTS SUFFICIENTLY TO
GENERATE BRIEF MODERATE RAINFALL AND PERHAPS SOME SMALL HAIL.
25-35KT SWLY TRANSPORT WINDS SHOULD CARRY THIS FIRST WAVE OF
CONVECTION OVER THE NEARBY PLAINS BETWEEN 1 AND 3 PM MDT BUT WITH
A FAIR AMOUNT CONVECTIVE INHABITION-CIN AROUND...MOST OF THIS
EARLY AFTERNOON STORM ACTIVITY SHOULD WEAKEN/DISSIPATE AS THEY
TRACK NORTHEAST OVER THE PLAINS. WHILE ALL THIS IS GOING ON...
MODELS SHOW A DENVER CYCLONE FORMING SOUTH/SOUTHEAST OF THE METRO
AREA EARLY THIS AFTERNOON. ITS FORMATION ENHANCES SOUTHEAST LOW-
LEVEL FLOW WHICH ADVECTS HIGHER DEWPTS/THETA-E VALUES OVER SRN
PORTIONS OF THE URBAN CORRIDOR RESULTING IN STEEP 700-500MB LAPSE
RATES. MODELS SHOW THE CYCLONE CONTINUING TO WIND UP CREATING A
WIND SHEAR AXIS/VORTICITY-CONVERGENCE ZONE WHICH MODELS SHOW
EXTENDING FROM CENTRAL DOUGLAS...SOUTHEAST DENVER AND SOUTHWEST
ARAPAHOE COUNTIES. MEANWHILE UPSTREAM...A WEAK SHORTWAVE TROUGH
SHOWING UP ON UPPER AIR PLOTS AND H20 VAPOR SATELLITE IMAGERY WAS
RACING NEWRD ACROSS THE STATE. TIMED ITS ARRIVAL IN THE DENVER
AREA NEAR 00Z TODAY. CONSEQUENTLY...LOOKING FOR THE 2ND WAVE OF
ISOLATED TO MULTI-CELL T-STORMS TO FORM ALONG THIS SHEAR AXIS LATE
AFTERNOON. STORMS WILL HAVE THE POTENTIAL TO PRODUCE BRIEF
MODERATE TO HEAVY RAIN AND SEVERE HAIL. MOST SHOWERS/STORMS WILL
TRACK NORTHEAST WITH THE 30KT SWLY TRANSPORT FLOW...BUT WE MAY
ALSO SEE A FEW STRONG TO PERHAPS SEVERE STORMS FORMING ON OUTFLOW
BOUNDARIES RADIATING NORTH ACROSS THE ERN DENVER METRO AREA UP
INTO SOUTHERN WELD COUNTY...AND EASTWARD ACROSS EASTERN
DOUGLAS...ARAPAHOE AND ELBERT COUNTIES DURING THE EARLY EVENING
HOURS. LARGE HAIL APPEARS TO BE THE MAIN SEVERE WEATHER THREAT
TODAY. HOWEVER WOULD NOT RULE OUT A BRIEF/WEAK TORNADO OR TWO IN
THE VICINITY OF THE DENVER CYCLONE. THIS EVENING STORMS WILL
CONTINUE TO RACE NORTHEAST INTO COOLER LESS UNSTABLE AIR WHERE
MOST WILL WEAKEN/DISSIPATE...BUT NOT BEFORE SENDING OUT OF SURGE
OF RAIN COOLED AIR BACK TOWARDS THE FRONT RANGE. LATER TONIGHT...
COULD SEE A REPEAT OF THE LOW CLOUDS AND PATCHY FOG ON THE PLAINS
AND LOWER FOOTHILLS. MTN AREAS SHOULD BE DRY OVERNIGHT AFTER
COLLAPSE OF EARLY EVENING CONVECTION.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 340 AM MDT TUE MAY 20 2014
MAIN CONCERN TODAY WILL BE THREAT OF THUNDERSTORMS AND SEVERE
WEATHER.
LATEST RADAR SHOWS A FEW SHOWERS AND STORMS MOVING QUICKLY
NORTHEAST ACROSS THE NORTHEAST PLAINS EARLY THIS MORNING. MOST OF
THESE WILL BE EXITING THE STATE BY OR SHORTLY AFTER DAYBREAK
ALTHOUGH CANT TOTALLY RULE OUT AN ISOLATED STORM LINGERING BEHIND
AS CURRENT CONVECTION HAS BEEN DEVELOPING ON JET STREAK/CLOUD
PLUME STRETCHING OUT OF THE DESERT SOUTHWEST. OTHERWISE LOOK FOR A
CLOUDY START TO THE DAY ON THE PLAINS WITH WIDESPREAD STRATUS
DECK...WHILE MOSTLY CLEAR SKIES PREVAIL IN THE MOUNTAINS.
THE CLOUDS TO THE NORTH AND SUNSHINE TO THE SOUTH WILL INCREASE
THE BAROCLINICITY ON THE HIGH PLAINS AND AID DEVELOPMENT OF A
CYCLONIC CONVERGENCE ZONE. AT THIS TIME...THE FRONTAL SURGE HAS
PUSHED SUBSTANTIALLY SOUTHWARD INTO SOUTHEAST COLORADO...SO MOST
LIKELY LOCATION OF LOW LEVEL CONVERGENCE ZONE THIS AFTERNOON WILL
BE NEAR THE PALMER DIVIDE. BELIEVE THE RAP IS CONSIDERABLY
OVERDOING THE MIXING AND DRYING...WHILE LATEST NAM IS DOING A
BETTER JOB. AS A RESULT...HIGHEST RISK OF STORM INITIATION WILL BE
OVER THE ELEVATED TERRAIN AND PALMER DIVIDE AS THE NORTHEAST
PLAINS WILL LIKELY REMAIN CAPPED WITH RESPECT TO SURFACE BASED
CONVECTION THROUGH MOST OF THE AFTERNOON. IF THE STORMS GET GOING
IN/NEAR THE HIGHER TERRAIN LATE THIS AFTERNOON...THEY SHOULD BE
ABLE TO HELP BREAK THE CAP AS THEY MOVE QUICKLY NORTHEAST ACROSS
THE PLAINS EARLY THIS EVENING. THERE IS SUFFICIENT CAPE...NEAR
1000 J/KG...WITH MID 40S DEWPOINTS FOR SEVERE STORMS WITH LARGE
HAIL BEING THE PRIMARY THREAT. LCLS ARE A BIT HIGH FOR TORNADO
PRODUCTION TODAY BUT STILL CANT RULE OUT AN ISOLATED SPINUP WITH
ENHANCED LOW LEVEL VORTICITY WHERE THE CONVERGENCE ZONE SETS UP.
STORMS WILL LIKELY CONTINUE THROUGH THE EVENING AND THEN GRADUALLY
DIMINISH FROM WEST TO EAST ACROSS THE PLAINS AFTER MIDNIGHT. COULD
SEE AREAS OF STRATUS REDEVELOP OVERNIGHT WITH MOIST EAST/SOUTHEAST
LOW LEVEL FLOW.
MOUNTAIN AREAS WEST OF THE FRONT RANGE WILL LIKELY STAY DRY
THROUGH TONIGHT WITH A MUCH DRIER AIRMASS HOLDING IN PLACE THERE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 340 AM MDT TUE MAY 20 2014
INCREASING RAIN CHANCES EXPECTED THROUGH THE REST OF THE WEEK AS THE
UPPER LOW OVER THE GREAT BASIN WILL BE SINKING SOUTH INTO SOUTHERN
CALIFORNIA AND ARIZONA WEDNESDAY. THIS WILL KEEP SOUTHERLY FLOW
OVER THE STATE AS IT REMAINS OVER THE SOUTHWEST THROUGH SATURDAY
MORNING BEFORE LIFTING NORTH.
HAVE STUCK TO MORE OF A NAM SOLUTION FOR WEDNESDAY WHICH WOULD
HAVE MORE MOISTURE AND UPSLOPE FLOW OVER THE PLAINS THAN THE GFS.
SOUTHEASTERLY WINDS AT THE SURFACE AND SOUTHWEST ALOFT WILL BE
INCREASING AVAILABLE MOISTURE WITH MODELED CAPES IN THE 1200-2000
J/KG RANGE. WITH THIS INSTABILITY AND AVAILABLE SHEAR...LOOKING
FOR MORE NUMEROUS THUNDERSTORMS ACROSS THE AREA WEDNESDAY WITH A
GREATER CHANCE OF SEVERE STORMS. LARGE HAIL...DAMAGING STRONG
WINDS AND TORNADOES ARE ALL A POSSIBILITY. DIFFERENCES IN MODELS
HAVE VARIED AREAS WITH MOST CONCERN FOR SEVERE WEATHER AT THIS
TIME. WILL LIKELY SEE STORMS FIRING OVER THE HIGHER TERRAIN AND
FOOTHILLS THEN SPREAD NORTHEAST OVER THE PLAINS THROUGH THE DAY
AND EVENING.
LOOKING FORWARD...MODELS SHOWING INCREASING PRECIPITABLE WATER
VALUES AS WELL AS AN INCREASE IN 700 MB SPECIFIC HUMIDITIES.
AVERAGE PW VALUE FOR DENVER THIS TIME OF YEAR IS AROUND 0.6". WE
BEGIN AROUND THAT VALUE...THEN MODELS HAVE VALUES NEAR 0.8" BY
SATURDAY. LOOKING AT 700 MB SPECIFIC HUMIDITY...THERE IS A PLUME
OF HIGHER VALUES MOVING UP INTO NEW MEXICO WEDNESDAY INTO
THURSDAY...WITH A MORE PROMINENT PLUME MOVING TOWARD THE STATE
FROM FRIDAY INTO THE WEEKEND. VALUES INCREASE TO THE 7-8.3 G/KG
RANGE FRIDAY. HOWEVER EACH MODEL HAS SMALL AREAS OF DRYING MOVING
OVER THE STATE AT DIFFERENT TIMES...AS WELL AS 700MB WINDS MOVING
BETWEEN A WETTER SOUTHEAST DIRECTION TO A DRYING SOUTHWEST
DIRECTION AT TIMES. SO OVERALL...LOOKING AT AN INCREASE IN SHOWERS
AND THUNDERSTORMS THROUGH THE WEEKEND...WITH A BETTER CHANCE OF
HEAVY RAIN FROM SOME OF THE STRONGER STORMS. WINDSPEEDS ALOFT ARE
BECOMING LIGHTER WHICH MAY ALLOW FOR SLOWER MOVING THUNDERSTORMS. THE
PERIODS OF UPSLOPE WILL FOCUS OUT ATTENTION ON THE FOOTHILLS AND
URBAN CORRIDOR. ONE GOOD THING HOWEVER...IS SOME OF THE RECENT
MODELS ARE MOVING THEIR FOCUS OF PRECIPITATION FURTHER EAST OVER
THE PLAINS...BUT THIS IS AGAIN GOING TO DEPEND ON THE MID LEVEL
WINDS. BEST DAY FOR HEAVIER RAIN POTENTIAL LOOKS TO BE
FRIDAY...HAVE INCREASED SHOWER AND THUNDERSTORMS CHANCES TO
LIKELY. IN TERMS OF SNOWMELT...TEMPERATURES WON`T BE TOO QUICK TO
WARM UP AND GENERALLY HOLDING STEADY EACH DAY AND NIGHT EXTREMES.
EXPECT NEAR OR SLIGHTLY COOLER MAX TEMPS AND NEAR NORMAL MIN TEMPS
FOR THE PERIOD.
THE UNSETTLED PATTERN IS EXPECTED CONTINUE THROUGH THE HOLIDAY
WEEKEND AS THE UPPER LOW MOVES ACROSS THE STATE AND EAST ON
MONDAY. SOME WRAPAROUND MOISTURE WILL LIKELY KEEP SHOWERS IN THE
FORECAST THROUGH MONDAY AS WELL...ALTHOUGH SLIGHTLY DRIER.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1050 AM MDT TUE MAY 20 2014
LOW CLOUDS WILL CONTINUE TO MIX OUT/DISSIPATE IN THE DENVER METRO
AREA FOR THE REMAINDER OF THE MORNING AS WINDS GO FROM LIGHT AND
VARIABLE TO EAST-SOUTHEAST AT 6-12KS BY EARLY THIS AFTERNOON. ITS
LATE THIS AFTERNOON WITH HEATING...MOIST UPSLOPE FLOW AND THE
PRESENCE OF A DENVER CYCLONE SITTING SOUTHEAST OF THE METRO
AREA...THAT THE CHANCE OF SHOWERS AND T-STORMS WILL QUICKLY
INCREASE. KDEN AND KAPA HAVE THE BEST CHANCE OF SEEING T-STORMS
LATE THIS AFTERNOON THROUGH EARLY THIS EVENING. HAIL WILL BE THE
MAIN THREAT...TOGETHER WITH BRIEF MODERATE TO HEAVY RAINFALL AND
VARIABLE WIND GUSTS TO 30KTS. THERE IS ALSO A SLIGHT CHANCE THAT
ONE OF THE LATE AFTERNOON/EARLY EVENING STORMS COULD PRODUCE A
BRIEF WEAK TORNADO. MOST OF THIS STORM ACTIVITY SHOULD MOVE OUT OF
THE DENVER AREA BY MID-EVENING/03Z-04Z. OVERNIGHT MOIST OUTFLOW
FROM THESE DYING STORMS ARE EXPECTED TO COVER THE DENVER METRO
AREA WITH LOW CLOUDS/IFR CONDITIONS AT DENVER AREA TERMINALS AFTER
MIDNIGHT TONIGHT THROUGH MID-MORNING ON WEDNESDAY. PREVAILING CIGS
AS LOW AS 1500-2000 FT AGL ARE ANTICIPATED.
&&
.HYDROLOGY...
ISSUED AT 1050 AM MDT TUE MAY 20 2014
ISOLATED TO SCATTERED SHOWERS/T-STORMS FORMING OVER THE FRONT
RANGE AROUND MIDDAY TODAY WITH DRIFT NORTHEAST OVER THE FOOTHILLS
AND NEARBY PLAINS AFTER 1 PM. THESE STORMS MAY PRODUCE UPWARDS OF
A QUARTER INCH OF RAIN IN 25 MINS AND HAIL UP TO 3/4 INCH IN
DIAMETER. FORTUNATELY FAST STORM MOTIONS SHOULD REDUCE THE RISK OF
HEAVY RAINFALL RESULTING IN FLOODING/FLASH FLOODING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BAKER
SHORT TERM...BARJENBRUCH
LONG TERM...KRIEDERMAN
AVIATION...BAKER
HYDROLOGY...BAKER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
352 PM EDT TUE MAY 20 2014
.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS OVER THE AREA INTO WEDNESDAY. A COMPLEX
STORM SYSTEM WILL IMPACT THE REGION FOR THE END OF THE WEEK. HIGH
PRESSURE THEN BUILDS OVER THE AREA EARLY NEXT WEEK. A STORM SYSTEM
APPROACHES FROM THE WEST NEXT TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
DEEP LAYERED RIDGING BUILDS IN TONIGHT. LATEST RADAR TRENDS
SUGGEST THAT AREA OF -SHRA WITH EMBEDDED ISOLD TS OVER THE
EASTERN GREAT LAKES MIGHT CLIP FAR SW PORTIONS OF THE CWA THIS
EVENING...IF IT HOLDS TOGETHER AT ALL. LATEST HRRR APPEARS TO
FOCUSED ON LEADING EDGE OF -SHRA WHICH HAS BEEN DISSIPATING...SO
APPEARS TO FAR WEST IN ITS FORECAST. ALSO 850-700 HPA
TRAJECTORIES ALSO FAVOR FARTHER WEST FORECAST. SO...HAVE SLIGHT
CHANCE POPS OVER FAR SW ZONES THIS EVENING...WITH THE REMAINDER
OF THE AREA DRY. WILL CONTINUE TO MONITOR IN CASE IT HOLDS
TOGETHER BETTER THAN EXPECTED - OR FOLLOWS MORE OF A MID VICE LOW
LEVEL STEERING FLOW - WHICH WOULD LEAD TO IT GOING FARTHER W - IF
IT HOLDS TOGETHER.
REGARDLESS...DO EXPECT AN INCREASE IN CLOUD COVER FROM W TO E
TONIGHT. THIS SHOULD HELP TO KEEP LOWS UP...THOUGH COULD HAVE A
BIT OF RADIATIONAL COOLING OVER EASTERN ZONES THIS EVENING BEFORE
CLOUDS MOVED IN. USED A BLEND OF MAV/MET GUIDANCE WITH NAM
2-METER TEMPERATURES WEST WHERE EXPECT LITTLE IF ANY RADIATIONAL
COOLING...AND MAV/MET GUIDANCE EAST WHERE RADIATIONAL COOLING IS
MORE LIKELY. LOWS SHOULD BE A FEW DEGREES ABOVE NORMAL.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS ARE IN GENERAL AGREEMENT THAT MULTIPLE SHORTWAVES WORK
THEIR WAY OVER THE TOP OF THE RIDGE AND IMPACT THE TRI-STATE FROM
TIME TO TIME WEDNESDAY AND WEDNESDAY NIGHT. HOWEVER...THEY DIFFER
ON TIMING AND LOCATION. AS A RESULT HAVE LIMITED POPS TO LOW END
LIKELY GIVEN THE UNCERTAINTY...AND RESTRICTED THIS TO AREAS
MAINLY NW OF NYC ON WEDNESDAY...BEFORE BRINGING POPS TO EVERYWHERE
WEDNESDAY NIGHT.
OF SOME CONCERN FOR PRECIPITATION CHANCES ON WEDNESDAY IS THAT
NAM /CMC-REGIONAL/ECMWF SUGGEST THAT ANY PRECIPITATION IS
CONFINED TO AREAS MAINLY W OF NYC AND ARRIVES MAINLY LATE IN THE
AFTERNOON...WHILE THE GFS HAS PRECIPITATION ARRIVE A BIT
SOONER...AND IS FARTHER E WITH ITS CORE. BASED ON MODEL
SPREAD...WOULD NOT BE SURPRISED IF THE AREA REMAINED DRY
WEDNESDAY...OR HAD A DECENT MCS ENTERING NW OR NORTH CENTRAL
PORTIONS OF THE CWA BY LATE AFTERNOON.
BOTTOM LINE IS DO NOT EXPECT EITHER WEDNESDAY OR WEDNESDAY NIGHT
TO BE A WASH OUT...AND IN FACT EXPECT MOST OF BOTH TIME FRAMES
THAT MOST AREAS WILL BE DRY. HOWEVER...DO EXPECT THAT AT SOME
POINT MAINLY FROM LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT
THAT IT IS LIKELY THAT MOST OF...IF NOT THE ENTIRE...CWA WILL
EXPERIENCE A FEW HOURS OF MODERATE TO POSSIBLY LOCALLY HEAVY
RAINFALL.
NOTING THAT LIGHTNING WAS ONGOING THIS MORNING WITH DYING MCS
OVER THE GREAT LAKES...HAVE INCLUDED A SLIGHT CHANCE OF THUNDER
FOR WEDNESDAY AFTERNOON...AND A CHANCE OF THUNDER FOR WEDNESDAY
NIGHT - WHEN IT APPEARS THERE IS THE GREATEST CHANCE TO IMPACTED
BY ONE OR MAYBE MORE (2 TO POSSIBLY 3) OF THESE SHORTWAVES GOING
OVER THE TOP OF THE RIDGE.
USED A BLEND OF MAV/MET GUIDANCE...MIXING DOWN FROM 925 HPA PER
BUFKIT SOUNDINGS...AND NAM 2-METER TEMPERATURES FOR HIGHS
WEDNESDAY...WITH VALUES FORECAST TO BE AROUND NORMAL FOR THIS TIME
OF YEAR. FOR LOWS WEDNESDAY NIGHT...USED A BLEND OF MAV/MET
GUIDANCE WITH NAM 2-METER TEMPERATURES WITH LOWS FORECAST TO BE
NEAR TO A FEW DEGREES ABOVE NORMAL.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
UPPER TROUGH BUILDS OVER THE AREA FOR THE END OF THE WEEK. SEVERAL
WAVES OF LOW PRES AND IMPULSES IN THE UPPER LEVELS OF THE
ATMOSPHERE WILL ROTATE AROUND THIS TROUGH...KEEPING UNSETTLED
WEATHER IN THE FORECAST THROUGH THE START OF THE WEEKEND.
DECAYING MCS PASSES WEST OF THE AREA THURSDAY MORNING...AND THEN
MOVES OFFSHORE AND SOUTH OF LONG ISLAND IN THE AFTERNOON. LOCALLY
HEAVY RAIN IS POSSIBLE IN THE MORNING...MAINLY FOR WESTERN ZONES.
GOING THROUGH THE AFTERNOON...SEVERAL STRONG H5 SHORTWAVES WILL
DIVE INTO THE REGION. WITH ONSHORE FLOW...WILL BE HARD FOR MOST OF
THE AREA TO GET OUT OF THE 60S FOR DAYTIME HIGHS...AND SOME AREAS
NEAR THE COASTS...ESPECIALLY OUT EAST...MAY NOT RISE MUCH ABOVE
60. THIS WILL LIMIT CAPE VALUES...AND SHOULD HELP SUPPRESS
CONVECTION IN THE AFTERNOON.
THIS SIMILAR PATTERN WILL CONTINUE FOR FRIDAY AND SATURDAY. SEVERAL
STRONG H5 SHORTWAVES WILL ROTATE AROUND THE UPPER TROUGH.
DIURNALLY DRIVEN CONVECTION POSSIBLE IN THE AFTERNOON AND EVENING.
DO NOT THINK EACH DAY WILL BE A WASHOUT...SO WILL ONLY CARRY
CHANCE POPS AT THIS TIME.
UPPER TROUGH DEPARTS SATURDAY NIGHT AND THEN HIGH PRES BUILDS EAST
FOR SUNDAY. COULD HAVE ONE LAST SHORTWAVE DIVE INTO THE REGION...
TOUCHING OFF SOME ISOLATED SHOWERS AND THUNDERSTORMS...MAINLY
ACROSS NORTHERN ZONES. OTHERWISE...MOSTLY SUNNY AND WARM SUNDAY
AND MONDAY WITH HIGHS IN THE MID 70S SUNDAY AND IN THE MID TO
UPPER 70S ON MONDAY.
NEXT SYSTEM APPROACHES FOR THE MIDDLE OF THE WEEK...POSSIBLY
TOUCHING OFF SOME AFTERNOON SHOWERS/STORMS ON TUESDAY.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
HIGH PRES OVER PA WILL BUILD OVER THE AREA TONIGHT AND OFFSHORE
ON WED.
VFR THROUGH THE TAF PERIOD.
NW FLOW TODAY WITH WIND DIRECTION VRB AT TIMES THROUGH 22-00Z.
GUSTS DECREASE TONIGHT WITH WINDS LGT AND VRB OVERNIGHT. SE FLOW
DEVELOPS DURING THE DAY WED WITH SPEEDS GENERALLY AT OR BELOW
11KT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: SOME VARIABILITY IN THE FLOW LIKELY THROUGH
20Z. WINDS MAY RANGE FROM 270 TO 320 TRUE AT TIMES.
KJFK FCSTER COMMENTS: VARIABILITY IN WIND DIRECTION THROUGH EARLY
THIS EVENING DUE TO POTENTIAL SEA BREEZE INFLUENCE. WINDS
GENERALLY RANGING 260-310 TRUE. GUSTS MAY BE MORE OCCASIONAL.
KLGA FCSTER COMMENTS: SOME VARIABILITY IN THE FLOW LIKELY THROUGH
THIS EVENING. WINDS MAY RANGE 300-350 TRUE AT TIMES.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
.OUTLOOK FOR 18Z WED THROUGH SUN...
.WED AFTERNOON...VRF WITH SE FLOW.
.WED NIGHT...SE FLOW WITH MVFR OR LOWER LIKELY. POTENTIAL FOR ORGANIZED
CONVECTIVE COMPLEX TO TRACK NEAR THE REGION.
.THU...MVFR OR LOWER LIKELY WITH SHRA. ISOLATED TSRA.
.FRI-SAT...PERIODS OF MVFR OR LOWER POSSIBLE. VRB WINDS.
.SUN...VFR WITH WINDS BECOMING NW.
&&
.MARINE...
A RELATIVELY RELAXED PRESSURE GRADIENT OVER THE WATERS WILL KEEP
WINDS TO 10 KT OR LESS THROUGH WEDNESDAY NIGHT...EXCEPT FOR 10-15
KT OVER ANZ-355 AND ANZ-353 WHERE EAST FLOW INCREASES WITH A
COASTAL LOW DEVELOPING TO THE S DURING THE NIGHT. COULD SEE SOME
GUSTS UP TO 20 KT IN THOSE AREAS LATE. SEAS SHOULD REMAIN BELOW
SMALL CRAFT THRESHOLDS THROUGH WEDNESDAY NIGHT BASED ON THE
RELATIVELY LIGHT WINDS.
GENERALLY SUB-SCA CONDITIONS ON TAP FROM THURSDAY INTO THE WEEKEND. A
LONG PERIOD SE SWELL OF A FOOT OR TWO IS EXPECTED TO PREVAIL INTO
AT LEAST FRIDAY...IMPACTING THE COASTAL OCEAN WATERS AND FAR
EASTERN PORTIONS OF LONG ISLAND SOUND.
&&
.HYDROLOGY...
MAINLY DRY THROUGH WEDNESDAY MORNING...THOUGH SW ZONES COULD SEE
LESS THAN A TENTH OF AN INCH OF RAIN IN ANY SHOWERS THAT HAPPEN TO
MOVE INTO THE AREA THE AREA THIS EVENING.
THERE IS THE POTENTIAL FOR 1/3 TO 2/3 AN INCH BASIN AVERAGE QPF
FROM WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...WITH LOCALLY HIGHER
AMOUNTS POSSIBLE.
ADDITIONAL SHOWERS AND THUNDERSTORMS COULD PRODUCE UP TO AN
ADDITIONAL 1/2 INCH QPF FRIDAY AND SATURDAY.
MINOR URBAN/SMALL STREAM FLOODING IS POSSIBLE...MAINLY IN AREAS
RECEIVING LOCALLY HEAVY RAINFALL FROM WEDNESDAY AFTERNOON THROUGH
THURSDAY NIGHT. THE OVERALL PROBABILITY OF FLOODING IS LOW AT
THIS TIME.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/MPS
NEAR TERM...MALOIT
SHORT TERM...MALOIT
LONG TERM...MPS
AVIATION...JMC
MARINE...MALOIT/MPS
HYDROLOGY...MALOIT/MPS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
330 PM EDT TUE MAY 20 2014
.SYNOPSIS...
WEAK HIGH PRESSURE BUILDS OVER THE AREA INTO WEDNESDAY. A COMPLEX
STORM SYSTEM WILL IMPACT THE REGION FOR THE END OF THE WEEK. HIGH
PRESSURE THEN BUILDS OVER THE AREA EARLY NEXT WEEK. A STORM SYSTEM
APPROACHES FROM THE WEST NEXT TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
DEEP LAYERED RIDGING BUILDS IN TONIGHT. LATEST RADAR TRENDS
SUGGEST THAT AREA OF -SHRA WITH EMBEDDED ISOLD TS OVER THE
EASTERN GREAT LAKES MIGHT CLIP FAR SW PORTIONS OF THE CWA THIS
EVENING...IF IT HOLDS TOGETHER AT ALL. LATEST HRRR APPEARS TO
FOCUSED ON LEADING EDGE OF -SHRA WHICH HAS BEEN DISSIPATING...SO
APPEARS TO FAR WEST IN ITS FORECAST. ALSO 850-700 HPA
TRAJECTORIES ALSO FAVOR FARTHER WEST FORECAST. SO...HAVE SLIGHT
CHANCE POPS OVER FAR SW ZONES THIS EVENING...WITH THE REMAINDER
OF THE AREA DRY. WILL CONTINUE TO MONITOR IN CASE IT HOLDS
TOGETHER BETTER THAN EXPECTED - OR FOLLOWS MORE OF A MID VICE LOW
LEVEL STEERING FLOW - WHICH WOULD LEAD TO IT GOING FARTHER W - IF
IT HOLDS TOGETHER.
REGARDLESS...DO EXPECT AN INCREASE IN CLOUD COVER FROM W TO E
TONIGHT. THIS SHOULD HELP TO KEEP LOWS UP...THOUGH COULD HAVE A
BIT OF RADIATIONAL COOLING OVER EASTERN ZONES THIS EVENING BEFORE
CLOUDS MOVED IN. USED A BLEND OF MAV/MET GUIDANCE WITH NAM
2-METER TEMPERATURES WEST WHERE EXPECT LITTLE IF ANY RADIATIONAL
COOLING...AND MAV/MET GUIDANCE EAST WHERE RADIATIONAL COOLING IS
MORE LIKELY. LOWS SHOULD BE A FEW DEGREES ABOVE NORMAL.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS ARE IN GENERAL AGREEMENT THAT MULTIPLE SHORTWAVES WORK
THEIR WAY OVER THE TOP OF THE RIDGE AND IMPACT THE TRI-STATE FROM
TIME TO TIME WEDNESDAY AND WEDNESDAY NIGHT. HOWEVER...THEY DIFFER
ON TIMING AND LOCATION. AS A RESULT HAVE LIMITED POPS TO LOW END
LIKELY GIVEN THE UNCERTAINTY...AND RESTRICTED THIS TO AREAS
MAINLY NW OF NYC ON WEDNESDAY...BEFORE BRINGING POPS TO EVERYWHERE
WEDNESDAY NIGHT.
OF SOME CONCERN FOR PRECIPITATION CHANCES ON WEDNESDAY IS THAT
NAM /CMC-REGIONAL/ECMWF SUGGEST THAT ANY PRECIPITATION IS
CONFINED TO AREAS MAINLY W OF NYC AND ARRIVES MAINLY LATE IN THE
AFTERNOON...WHILE THE GFS HAS PRECIPITATION ARRIVE A BIT
SOONER...AND IS FARTHER E WITH ITS CORE. BASED ON MODEL
SPREAD...WOULD NOT BE SURPRISED IF THE AREA REMAINED DRY
WEDNESDAY...OR HAD A DECENT MCS ENTERING NW OR NORTH CENTRAL
PORTIONS OF THE CWA BY LATE AFTERNOON.
BOTTOM LINE IS DO NOT EXPECT EITHER WEDNESDAY OR WEDNESDAY NIGHT
TO BE A WASH OUT...AND IN FACT EXPECT MOST OF BOTH TIME FRAMES
THAT MOST AREAS WILL BE DRY. HOWEVER...DO EXPECT THAT AT SOME
POINT MAINLY FROM LATE WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT
THAT IT IS LIKELY THAT MOST OF...IF NOT THE ENTIRE...CWA WILL
EXPERIENCE A FEW HOURS OF MODERATE TO POSSIBLY LOCALLY HEAVY
RAINFALL.
NOTING THAT LIGHTNING WAS ONGOING THIS MORNING WITH DYING MCS
OVER THE GREAT LAKES...HAVE INCLUDED A SLIGHT CHANCE OF THUNDER
FOR WEDNESDAY AFTERNOON...AND A CHANCE OF THUNDER FOR WEDNESDAY
NIGHT - WHEN IT APPEARS THERE IS THE GREATEST CHANCE TO IMPACTED
BY ONE OR MAYBE MORE (2 TO POSSIBLY 3) OF THESE SHORTWAVES GOING
OVER THE TOP OF THE RIDGE.
USED A BLEND OF MAV/MET GUIDANCE...MIXING DOWN FROM 925 HPA PER
BUFKIT SOUNDINGS...AND NAM 2-METER TEMPERATURES FOR HIGHS
WEDNESDAY...WITH VALUES FORECAST TO BE AROUND NORMAL FOR THIS TIME
OF YEAR. FOR LOWS WEDNESDAY NIGHT...USED A BLEND OF MAV/MET
GUIDANCE WITH NAM 2-METER TEMPERATURES WITH LOWS FORECAST TO BE
NEAR TO A FEW DEGREES ABOVE NORMAL.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
UPPER TROUGH BUILDS OVER THE AREA FOR THE END OF THE WEEK. SEVERAL
WAVES OF LOW PRES AND IMPULSES IN THE UPPER LEVELS OF THE
ATMOSPHERE WILL ROTATE AROUND THIS TROUGH...KEEPING UNSETTLED
WEATHER IN THE FORECAST THROUGH THE START OF THE WEEKEND.
DECAYING MCS PASSES WEST OF THE AREA THURSDAY MORNING...AND THEN
MOVES OFFSHORE AND SOUTH OF LONG ISLAND IN THE AFTERNOON. LOCALLY
HEAVY RAIN IS POSSIBLE IN THE MORNING...MAINLY FOR WESTERN ZONES.
GOING THROUGH THE AFTERNOON...SEVERAL STRONG H5 SHORTWAVES WILL
DIVE INTO THE REGION. WITH ONSHORE FLOW...WILL BE HARD FOR MOST OF
THE AREA TO GET OUT OF THE 60S FOR DAYTIME HIGHS...AND SOME AREAS
NEAR THE COASTS...ESPECIALLY OUT EAST...MAY NOT RISE MUCH ABOVE
60. THIS WILL LIMIT CAPE VALUES...AND SHOULD HELP SUPPRESS
CONVECTION IN THE AFTERNOON.
THIS SIMILAR PATTERN WILL CONTINUE FOR FRIDAY AND SATURDAY. SEVERAL
STRONG H5 SHORTWAVES WILL ROTATE AROUND THE UPPER TROUGH.
DIURNALLY DRIVEN CONVECTION POSSIBLE IN THE AFTERNOON AND EVENING.
DO NOT THINK EACH DAY WILL BE A WASHOUT...SO WILL ONLY CARRY
CHANCE POPS AT THIS TIME.
UPPER TROUGH DEPARTS SATURDAY NIGHT AND THEN HIGH PRES BUILDS EAST
FOR SUNDAY. COULD HAVE ONE LAST SHORTWAVE DIVE INTO THE REGION...
TOUCHING OFF SOME ISOLATED SHOWERS AND THUNDERSTORMS...MAINLY
ACROSS NORTHERN ZONES. OTHERWISE...MOSTLY SUNNY AND WARM SUNDAY
AND MONDAY WITH HIGHS IN THE MID 70S SUNDAY AND IN THE MID TO
UPPER 70S ON MONDAY.
NEXT SYSTEM APPROACHES FOR THE MIDDLE OF THE WEEK...POSSIBLY
TOUCHING OFF SOME AFTERNOON SHOWERS/STORMS ON TUESDAY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
HIGH PRES OVER PA WILL BUILD OVER THE AREA TONIGHT AND OFFSHORE
ON WED.
VFR THROUGH THE TAF PERIOD.
NW FLOW TODAY WITH WIND DIRECTION VRB AT TIMES THROUGH 22-00Z.
GUSTS DECREASE TONIGHT WITH WINDS LGT AND VRB OVERNIGHT. SE FLOW
DEVELOPS DURING THE DAY WED WITH SPEEDS GENERALLY AT OR BELOW
11KT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: SOME VARIABILITY IN THE FLOW LIKELY THROUGH
20Z. WINDS MAY RANGE FROM 340 TO 290 TRUE AT TIMES.
KJFK FCSTER COMMENTS: SOME VARIABILITY IN THE FLOW LIKELY THROUGH
19-21Z WITH A RANGE UP TO 340 TRUE. SEA BREEZE POTENTIAL REMAINS
LOW BUT THE TEMPO WAS MAINTAINED IN THE TAF BECAUSE THERE ARE
SOME DATA SETS THAT INSIST IT WILL OCCUR.
KLGA FCSTER COMMENTS: SOME VARIABILITY IN THE FLOW LIKELY THROUGH
20Z. WINDS MAY RANGE FROM 350 TO 300 TRUE AT TIMES.
KTEB FCSTER COMMENTS: SOME VARIABILITY IN THE FLOW POSSIBLE THROUGH
20Z.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
.OUTLOOK FOR 18Z WED THROUGH SUN...
.WED AFTERNOON...VRF WITH SE FLOW.
.WED NIGHT...SE FLOW WITH MVFR OR LOWER LIKELY. POTENTIAL FOR ORGANIZED
CONVECTIVE COMPLEX TO TRACK NEAR THE REGION.
.THU...MVFR OR LOWER LIKELY WITH SHRA. ISOLATED TSRA.
.FRI-SAT...PERIODS OF MVFR OR LOWER POSSIBLE. VRB WINDS.
.SUN...VFR WITH WINDS BECOMING NW.
&&
.MARINE...
A RELATIVELY RELAXED PRESSURE GRADIENT OVER THE WATERS WILL KEEP
WINDS TO 10 KT OR LESS THROUGH WEDNESDAY NIGHT...EXCEPT FOR 10-15
KT OVER ANZ-355 AND ANZ-353 WHERE EAST FLOW INCREASES WITH A
COASTAL LOW DEVELOPING TO THE S DURING THE NIGHT. COULD SEE SOME
GUSTS UP TO 20 KT IN THOSE AREAS LATE. SEAS SHOULD REMAIN BELOW
SMALL CRAFT THRESHOLDS THROUGH WEDNESDAY NIGHT BASED ON THE
RELATIVELY LIGHT WINDS.
GENERALLY SUB-SCA CONDITIONS ON TAP FROM THURSDAY INTO THE WEEKEND. A
LONG PERIOD SE SWELL OF A FOOT OR TWO IS EXPECTED TO PREVAIL INTO
AT LEAST FRIDAY...IMPACTING THE COASTAL OCEAN WATERS AND FAR
EASTERN PORTIONS OF LONG ISLAND SOUND.
&&
.HYDROLOGY...
MAINLY DRY THROUGH WEDNESDAY MORNING...THOUGH SW ZONES COULD SEE
LESS THAN A TENTH OF AN INCH OF RAIN IN ANY SHOWERS THAT HAPPEN TO
MOVE INTO THE AREA THE AREA THIS EVENING.
THERE IS THE POTENTIAL FOR 1/3 TO 2/3 AN INCH BASIN AVERAGE QPF
FROM WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...WITH LOCALLY HIGHER
AMOUNTS POSSIBLE.
ADDITIONAL SHOWERS AND THUNDERSTORMS COULD PRODUCE UP TO AN
ADDITIONAL 1/2 INCH QPF FRIDAY AND SATURDAY.
MINOR URBAN/SMALL STREAM FLOODING IS POSSIBLE...MAINLY IN AREAS
RECEIVING LOCALLY HEAVY RAINFALL FROM WEDNESDAY AFTERNOON THROUGH
THURSDAY NIGHT. THE OVERALL PROBABILITY OF FLOODING IS LOW AT
THIS TIME.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/MPS
NEAR TERM...MALOIT
SHORT TERM...MALOIT
LONG TERM...MPS
AVIATION...JMC
MARINE...MALOIT/MPS
HYDROLOGY...MALOIT/MPS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
417 PM EDT TUE MAY 20 2014
.SYNOPSIS...
A WARM FRONT DEVELOPING FROM THE GREAT LAKES TO VIRGINIA TONIGHT
WILL MOVE TO THE SOUTHERN NEW JERSEY DELAWARE COASTS WEDNESDAY NIGHT
WHERE LOW PRESSURE FORMS AND HEADS OUT TO SEA. A COLD FRONTAL
PASSAGE FOLLOWS LATER THURSDAY NIGHT. HIGH PRESSURE IN THE MIDWEST
ON FRIDAY FINALLY ARRIVES ALONG THE MID ATLANTIC COAST ON SUNDAY
THEN BECOMES PART OF THE BERMUDA HIGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE HIGH PRESSURE THAT WAS IN CONTROL OF THE WEATHER THE LAST FEW
DAYS HAS SAGGED SOUTH OF THE AREA AND IS NOW OFF THE SOUTHEAST
COAST. A WARM FRONT IS EXPECTED TO BEGIN LIFTING NORTHWARD OVERNIGHT
TONIGHT, BUT NOT QUITE MAKE IT TO OUR AREA OVERNIGHT. HOWEVER,
THERE IS STILL A COUPLE OF SHOTS FOR SHOWER ACTIVITY. FIRST, SHOWERS
ARE MOVING ACROSS FAR NORTHWEST PENNSYLVANIA AND WESTERN NEW YORK
STATE, ASSOCIATED WITH A WEAK SHORT WAVE/VORTICITY IMPULSE. MOST
MODELS SHOW SOME SORT OF LIGHT PRECIP AFFECTING THE NORTHERN HALF OF
THE AREA THIS EVENING AROUND SUNSET THROUGH MIDNIGHT. THE HRRR AND
ECMWF ARE MOST PRONOUNCED, WHILE THE GFS IS A LITTLE LESS AND THE
NAM HAS NOTHING. FOR NOW, WE WILL INTRODUCE ISOLATED SHOWERS THIS
EVENING FOR A FEW HOURS, FOLLOWED BY A BREAK, THEN ANOTHER INCREASE
IN POPS TOWARD DAYBREAK. THE SECOND CHANCE OF SHOWERS IS DUE TO THE
OVERRUNNING MOISTURE OVER TOP OF THE APPROACHING WARM FRONT AND
ANOTHER WEAK VORT IMPULSE.
OVERNIGHT LOWS WERE A BLEND OF MAV/MET MOS AND MOSGUIDE WITH A
SLIGHT INCREASE AS WE EXPECT AN SOME CLOUD COVER TONIGHT WHICH
SHOULD PREVENT SIGNIFICANT RADIATIONAL COOLING FROM TAKING PLACE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
THE WARM FRONT CONTINUES TO LIFT TOWARD THE AREA ON WEDNESDAY AND
SHOULD MAKE ITS WAY ACROSS AT LEAST OUR SOUTHERN AREAS DURING THE
DAY AS AN AREA OF LOW PRESSURE MOVES ACROSS THE GREAT LAKES REGION.
THERE WILL REMAIN A CHANCE OF SHOWERS DURING THE MORNING HOURS AS
MOISTURE WILL CONTINUE TO RIDE OVER TOP THE FRONT TO OUR SOUTH AND
WEAK PVA WILL KEEP SOME ENHANCED LIFT ACROSS THE AREA. HOWEVER,
SHOWERS ARE EXPECTED TO INCREASE IN COVERAGE THROUGH THE DAY,
ESPECIALLY LATER IN THE AFTERNOON AS A STRONGER SHORT WAVE/VORTICITY
IMPULSE APPROACHES FROM THE WEST. THERE IS SOME INSTABILITY ACROSS
THE AREA, ESPECIALLY THE WESTERN HALF OF THE AREA, WITH SOME
NEGATIVE LI VALUES, K-INDEX IN THE LOW-MID 30S, AND TOTAL TOTALS
CLOSE TO 50; THERE IS EVEN SOME CAPE FORECAST AS WELL. SO WE WILL
KEEP SCATTERED/ISOLATED THUNDERSTORMS IN THE FORECAST. THERE COULD
BE SOME HEAVIER RAIN WITH SOME OF THE SHOWERS/THUNDERSTORMS AS PW
VALUES APPROACH 1.5-1.75 INCHES.
HIGHS WERE A MAV/MET MOS AND MOSGUIDE BLEND WITH SLIGHTLY MORE
EMPHASIS ON THE SLIGHTLY COOLER MAV/MOSGUIDE TEMPERATURES DUE TO
EXPECTED CLOUD COVER AND POSSIBLE SHOWER ACTIVITY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
500MB: A SMALL CLOSED LOW IN SOUTH CENTRAL CANADA WEDNESDAY EVENING
EVOLVES INTO A LARGER CLOSED LOW SITUATED OVER THE MARITIMES BY
FRIDAY THEN MIDWEST RIDGING SLOWLY MIGRATES EAST TO REACH THE
APPALACHIANS BY TUESDAY.
TEMPERATURES: THE FIRST 19 DAYS OF THE MONTH HAVE AVERAGED GENERALLY
1.5 TO 3 DEGREES ABOVE NORMAL. CALENDAR DAY AVERAGE TEMPERATURES
SHOULD BE WITHIN SEVERAL DEGREES OF NORMAL THROUGH THIS WEEKEND THEN
WE BEGIN WHAT MAY BE SEVERAL DAYS OF A SIGNIFICANT WARMUP EARLY NEXT
WEEK.
FORECAST BASIS...UNLESS OTHERWISE NOTED THE LONG TERM PERIOD OF THIS
FORECAST IS GENERALLY BASED ON A 50 50 BLEND OF THE 12Z/20 NAM/GFS
MOS FOR THE PERIOD WEDNESDAY NIGHT-THURSDAY NIGHT... THE 12Z/20 GFS
MOS FOR FRIDAY AND FRIDAY NIGHT AND THEN THEREAFTER THE 1522Z/20
WPC GRIDDED GUIDANCE. THIS GUIDANCE IS CHECKED AGAINST THE 09Z/20
SREF POPS FOR .01 IN 3 HRS THROUGH FRIDAY AND THEREAFTER THE
12Z/20 GEFS 6HR POPS FOR .05. ADDITIONALLY...WE MAKE A SPOT CHECK OF
THE 12Z/20 OPERATIONAL GFS 2M TEMPS VS THE GEFS AND SEE WHERE
UNCERTAINTY (SPREAD IN SOLUTIONS) EXISTS AND REFERENCE THAT
UNCERTAINTY WITH RESPECT TO PROSPECTS FOR THE GFS MOS BEING
ACCURATE. THE 12Z GGEM/UKMET AND TO A LESSER EXTENT THE 12Z/20 ECMWF
ARE ALSO USED IN A BROAD BASED CHECK FOR SPREAD OF OPERATIONAL
SOLUTIONS AND USED ACCORDINGLY TO EXPRESS LESS CONFIDENCE IN
PROBABILITIES OF THE MOST LIKELY DAILY OUTCOMES.
THE DAILIES BELOW...
WEDNESDAY NIGHT...SHOWERS DURING THE EVENING AS LOW PRESSURE FORMS
IN NJ. RAIN MAY BE HEAVY FOR A TIME PER WPC 6 HR QPF OF ABOUT ONE
HALF INCH. THEN CLEARING ALOFT LATE AT NIGHT COMBINED WITH LIGHT
WINDS AT THE SURFACE IN A NEARLY SATURATED BOUNDARY LAYER SHOULD
PERMIT THE FORMATION OF FOG LATE. SOME OF THIS FOG MAY BE PATCHY 1/4
MI DENSE FOG...MAINLY AFTER MIDNIGHT.
THURSDAY...STILL SOME INSTABILITY AROUND BUT SEEMS POTENTIALLY TO BE
A LESSER RISK OF SHOWERS AS IT LOOKS PRETTY DRY ABOVE 700 MB? WE`LL
CALL IT SCT AFTN SHOWERS EXCEPT IN NE PA AND NNJ LIKELY POPS. BEST
CHANCE OF SHOWERS MAY BE ALONG A LEFTOVER BOUNDARY IN NJ AND NE PA WHERE
THERE MAY BE SOME LEFTOVER STABLE NORTHEASTERLY FLOW AND STRATUS
IN NORTHEASTERN NJ AND WARMER MORE UNSTABLE AIR TO THE SOUTHWEST OVER
PHL. IT COULD BE UNSTABLE ENOUGH FOR A TSTM. THE 12Z/20 NAM AND
GGEM ARE WARMER THAN OUR 330 PM FCST WHICH EVEN LOWERED THE 12Z/20
NCEP GFS MOS GUIDANCE BY SEVERAL DEGREES FROM PHL NORTHEASTWARD...IN
PART BECAUSE OF THE COOLER ECMWF. ONE AREA WHERE IT MAY BE MORE
EASILY WARMER THAN OUR 330 PM FCST IS MD`S E SHORE WHERE LOWER 80S
ARE POSSIBLE.
THURSDAY NIGHT...CHANCE OF AN EVENING SHOWER IN NJ AND NE PA
ASSOCIATED WITH LINGERING INSTABILITY...OTHERWISE WE`RE PROBABLY
LOOKING AT A DECENT NIGHT. CONSIDERABLE CLOUDINESS EARLY.
FRIDAY AND SATURDAY...GENERAL NW FLOW ALOFT WEAK INSTABILITY
ASSOCIATED WITH THE TROUGH ALOFT AND MAYBE AN EMBEDDED SHORT
WAVE. NOTHING YET SEEN AS ORGANIZED ATTM AND SEEMS LIKE SCT AFTN
SHOWERS BOTH AFTERNOONS. WEST TO NORTHWEST WIND GUST 15 MPH EACH
AFTN.
SUNDAY...DRY AND NICE! LIGHT NW WIND.
MONDAY...DRY AND WARMER. VERY NICE! LIGHT SW WIND.
TUESDAY...THERE IS A CHANCE OF SHOWERS AND TSTMS MAINLY LATE AS A
COLD FRONT APPROACHES FROM THE NORTHWEST. WESTERLY WIND.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
CLOUDS WILL INCREASE THROUGH THE NIGHT AND LOWER, BUT VFR CONDITIONS
ARE EXPECTED THROUGH TONIGHT AND MOST OF THE DAY WEDNESDAY. THERE IS
A CHANCE OF SOME ISOLATED SHOWERS LATER THIS EVENING, ESPECIALLY
ACROSS THE NORTHERN TAFS, BUT CONFIDENCE WAS NOT HIGH ENOUGH TO
INCLUDE IN THE TAFS AT THIS TIME. MORE CONFIDENCE IN SHOWER ACTIVITY
IS DURING THE DAY WEDNESDAY, WHICH WAS INTRODUCED AT SOME TAF SITES.
THERE IS THE POSSIBILITY FOR SOME SCATTERED THUNDERSTORMS, BUT THEY
WERE NOT INCLUDED AT THIS TIME.
WINDS VARIED FROM SOUTHWEST, TO WEST, TO NORTHWEST LATE THIS
AFTERNOON, AVERAGING AROUND 10 KNOTS WITH SOME GUSTS IN THE MID TO
UPPER TEENS. THE GUSTS WILL DIMINISH IN THE NEXT FEW HOURS, AND
WINDS COULD BECOME LIGHT AND VARIABLE FOR A PERIOD OVERNIGHT, BEFORE
INCREASING OUT OF THE SOUTHEAST WEDNESDAY MORNING INTO THE DAY.
OUTLOOK...
WEDNESDAY NIGHT...LOCALIZED IFR VISIBILITIES IN SHOWERS AND POSSIBLE
TSTMS DURING THE EVENING. OTHERWISE MVFR CIGS AOA 3500 FT TO START
THE EVENING PROBABLY BECOMING WIDESPREAD IFR AND SPOTTY LIFR IN
ST/FOG WITH LIGHT WIND IN THE WEAK WARM FRONTAL WAVE BAGGY
PRESSURE GRADIENT...ESP S NJ AND DE. RIGHT NOW THE 09Z/20 SREF
PROBS FOR LOW CIGS/VSBY ARE MEAGER WITH GREATEST RISK OF LOW
CIGS/VSBYS ALONG AND N OF I78 (KABE NORTHWARD).
THURSDAY...GENERALLY VFR CONDITIONS EXPECTED AFTER EARLY MORNING
IFR ST/FOG LIFTS. LOCALIZED MVFR CONDITIONS ASSOCIATED WITH SCT AFTN
SHOWERS. LIGHT WIND. IFR PATCHY FOG POSSIBLE AT NIGHT.
FRIDAY AND SATURDAY...GENERALLY VFR CONDITIONS EXPECTED, WITH
LOCALIZED MVFR CONDITIONS POSSIBLE WITH ANY SHOWERS. SMALL RISK OF
AFTERNOON TSRA EACH DAY. WNW WIND EA AFTN GUSTING 15 KT.
SUNDAY...VFR. LIGHT NW WIND.
&&
.MARINE...
SUB-ADVISORY CONDITIONS WILL PREVAIL THROUGH WEDNESDAY AS A WARM FRONT
CONTINUES TO LIFT TOWARD THE AREA. WINDS MAY OCCASIONALLY GUST AROUND
20 KNOTS, ESPECIALLY LATER ON WEDNESDAY.
OUTLOOK...
WEDNESDAY NIGHT THROUGH SUNDAY...WINDS AND SEAS ARE EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY CONDITIONS THROUGH THIS PERIOD. AN EXCEPTION
MAY BE WEDNESDAY NIGHT IN THE NNJ WATERS WHERE THE NE WIND MAY FORCE
A SMALL PERIOD OF 5 FT SEAS LATE AT NIGHT IN ANZ450-451.
THERE IS SOME RISK OF FOG DEVELOPING LATE WEDNESDAY NIGHT AHEAD OF
AN APPROACHING COLD FRONT.
THIS IS SAFE BOATING WEEK AND PUBLIC INFORMATION STATEMENTS WERE
ISSUED YESTERDAY AT 1247Z AND TODAY AT 1048Z.
&&
.RIP CURRENTS...
THERE IS STILL A MODERATE RISK OF RIP CURRENTS ALONG THE NEW JERSEY
COAST LATE TODAY.
&&
.EQUIPMENT...
THE KDIX RADAR REMAINS OUT OF SERVICE. TECHNICIANS WILL BE WORKING
ON THE PROBLEM THIS EVENING.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...DRAG 416
AVIATION...DRAG/ROBERTSON 416
MARINE...DRAG/ROBERTSON
RIP CURRENTS...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
351 PM EDT TUE MAY 20 2014
.SYNOPSIS...
A WARM FRONT DEVELOPING FROM THE GREAT LAKES TO VIRGINIA TONIGHT
WILL MOVE TO THE SOUTHERN NEW JERSEY DELAWARE COASTS WEDNESDAY NIGHT
WHERE LOW PRESSURE FORMS AND HEADS OUT TO SEA. A COLD FRONTAL
PASSAGE FOLLOWS LATER THURSDAY NIGHT. HIGH PRESSURE IN THE MIDWEST
ON FRIDAY FINALLY ARRIVES ALONG THE MID ATLANTIC COAST ON SUNDAY
THEN BECOMES PART OF THE BERMUDA HIGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE HIGH PRESSURE THAT WAS IN CONTROL OF THE WEATHER THE LAST FEW
DAYS HAS SAGGED SOUTH OF THE AREA AND IS NOW OFF THE SOUTHEAST
COAST. A WARM FRONT IS EXPECTED TO BEGIN LIFTING NORTHWARD OVERNIGHT
TONIGHT, BUT NOT QUITE MAKE IT TO OUR AREA OVERNIGHT. HOWEVER,
THERE IS STILL A COUPLE OF SHOTS FOR SHOWER ACTIVITY. FIRST, SHOWERS
ARE MOVING ACROSS FAR NORTHWEST PENNSYLVANIA AND WESTERN NEW YORK
STATE, ASSOCIATED WITH A WEAK SHORT WAVE/VORTICITY IMPULSE. MOST
MODELS SHOW SOME SORT OF LIGHT PRECIP AFFECTING THE NORTHERN HALF OF
THE AREA THIS EVENING AROUND SUNSET THROUGH MIDNIGHT. THE HRRR AND
ECMWF ARE MOST PRONOUNCED, WHILE THE GFS IS A LITTLE LESS AND THE
NAM HAS NOTHING. FOR NOW, WE WILL INTRODUCE ISOLATED SHOWERS THIS
EVENING FOR A FEW HOURS, FOLLOWED BY A BREAK, THEN ANOTHER INCREASE
IN POPS TOWARD DAYBREAK. THE SECOND CHANCE OF SHOWERS IS DUE TO THE
OVERRUNNING MOISTURE OVER TOP OF THE APPROACHING WARM FRONT AND
ANOTHER WEAK VORT IMPULSE.
OVERNIGHT LOWS WERE A BLEND OF MAV/MET MOS AND MOSGUIDE WITH A
SLIGHT INCREASE AS WE EXPECT AN SOME CLOUD COVER TONIGHT WHICH
SHOULD PREVENT SIGNIFICANT RADIATIONAL COOLING FROM TAKING PLACE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
THE WARM FRONT CONTINUES TO LIFT TOWARD THE AREA ON WEDNESDAY AND
SHOULD MAKE ITS WAY ACROSS AT LEAST OUR SOUTHERN AREAS DURING THE
DAY AS AN AREA OF LOW PRESSURE MOVES ACROSS THE GREAT LAKES REGION.
THERE WILL REMAIN A CHANCE OF SHOWERS DURING THE MORNING HOURS AS
MOISTURE WILL CONTINUE TO RIDE OVER TOP THE FRONT TO OUR SOUTH AND
WEAK PVA WILL KEEP SOME ENHANCED LIFT ACROSS THE AREA. HOWEVER,
SHOWERS ARE EXPECTED TO INCREASE IN COVERAGE THROUGH THE DAY,
ESPECIALLY LATER IN THE AFTERNOON AS A STRONGER SHORT WAVE/VORTICITY
IMPULSE APPROACHES FROM THE WEST. THERE IS SOME INSTABILITY ACROSS
THE AREA, ESPECIALLY THE WESTERN HALF OF THE AREA, WITH SOME
NEGATIVE LI VALUES, K-INDEX IN THE LOW-MID 30S, AND TOTAL TOTALS
CLOSE TO 50; THERE IS EVEN SOME CAPE FORECAST AS WELL. SO WE WILL
KEEP SCATTERED/ISOLATED THUNDERSTORMS IN THE FORECAST. THERE COULD
BE SOME HEAVIER RAIN WITH SOME OF THE SHOWERS/THUNDERSTORMS AS PW
VALUES APPROACH 1.5-1.75 INCHES.
HIGHS WERE A MAV/MET MOS AND MOSGUIDE BLEND WITH SLIGHTLY MORE
EMPHASIS ON THE SLIGHTLY COOLER MAV/MOSGUIDE TEMPERATURES DUE TO
EXPECTED CLOUD COVER AND POSSIBLE SHOWER ACTIVITY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
500MB: A SMALL CLOSED LOW IN SOUTH CENTRAL CANADA WEDNESDAY EVENING
EVOLVES INTO A LARGER CLOSED LOW SITUATED OVER THE MARITIMES BY
FRIDAY THEN MIDWEST RIDGING SLOWLY MIGRATES EAST TO REACH THE
APPALACHIANS BY TUESDAY.
TEMPERATURES: THE FIRST 19 DAYS OF THE MONTH HAVE AVERAGED GENERALLY
1.5 TO 3 DEGREES ABOVE NORMAL. CALENDAR DAY AVERAGE TEMPERATURES
SHOULD BE WITHIN SEVERAL DEGREES OF NORMAL THROUGH THIS WEEKEND THEN
WE BEGIN WHAT MAY BE SEVERAL DAYS OF A SIGNIFICANT WARMUP EARLY NEXT
WEEK.
FORECAST BASIS...UNLESS OTHERWISE NOTED THE LONG TERM PERIOD OF THIS
FORECAST IS GENERALLY BASED ON A 50 50 BLEND OF THE 12Z/20 NAM/GFS
MOS FOR THE PERIOD WEDNESDAY NIGHT-THURSDAY NIGHT... THE 12Z/20 GFS
MOS FOR FRIDAY AND FRIDAY NIGHT AND THEN THEREAFTER THE 1522Z/20
WPC GRIDDED GUIDANCE. THIS GUIDANCE IS CHECKED AGAINST THE 09Z/20
SREF POPS FOR .01 IN 3 HRS THROUGH FRIDAY AND THEREAFTER THE
12Z/20 GEFS 6HR POPS FOR .05. ADDITIONALLY...WE MAKE A SPOT CHECK OF
THE 12Z/20 OPERATIONAL GFS 2M TEMPS VS THE GEFS AND SEE WHERE
UNCERTAINTY (SPREAD IN SOLUTIONS) EXISTS AND REFERENCE THAT
UNCERTAINTY WITH RESPECT TO PROSPECTS FOR THE GFS MOS BEING
ACCURATE. THE 12Z GGEM/UKMET AND TO A LESSER EXTENT THE 12Z/20 ECMWF
ARE ALSO USED IN A BROAD BASED CHECK FOR SPREAD OF OPERATIONAL
SOLUTIONS AND USED ACCORDINGLY TO EXPRESS LESS CONFIDENCE IN
PROBABILITIES OF THE MOST LIKELY DAILY OUTCOMES.
THE DAILIES BELOW...
WEDNESDAY NIGHT...SHOWERS DURING THE EVENING AS LOW PRESSURE FORMS
IN NJ. RAIN MAY BE HEAVY FOR A TIME PER WPC 6 HR QPF OF ABOUT ONE
HALF INCH. THEN CLEARING ALOFT LATE AT NIGHT COMBINED WITH LIGHT
WINDS AT THE SURFACE IN A NEARLY SATURATED BOUNDARY LAYER SHOULD
PERMIT THE FORMATION OF FOG LATE.
THURSDAY...STILL SOME INSTABILITY AROUND BUT SEEMS POTENTIALLY TO BE
A LESSER RISK OF SHOWERS AS IT LOOKS PRETTY DRY ABOVE 700 MB? WE`LL
CALL IT SCT AFTN SHOWERS EXCEPT IN NE PA AND NNJ LIKELY POPS. BEST
CHANCE OF SHOWERS MAY BE ALONG A LEFTOVER BOUNDARY IN NJ AND NE PA WHERE
THERE MAY BE SOME LEFTOVER STABLE NORTHEASTERLY FLOW AND STRATUS
IN NORTHEASTERN NJ AND WARMER MORE UNSTABLE AIR TO THE SOUTHWEST OVER
PHL. IT COULD BE UNSTABLE ENOUGH FOR A TSTM. THE 12Z/20 NAM AND
GGEM ARE WARMER THAN OUR 330 PM FCST WHICH EVEN LOWERED THE 12Z/20
NCEP GFS MOS GUIDANCE BY SEVERAL DEGREES FROM PHL NORTHEASTWARD...IN
PART BECAUSE OF THE COOLER ECMWF. ONE AREA WHERE WE MAY MORE
EASILY WARMER THAN OUR FCST IS MD`S E SHORE WHERE LOWER 80S ARE
POSSIBLE.
THURSDAY NIGHT...CHANCE OF AN EVENING SHOWER IN NJ AND NE PA
ASSOCIATED WITH LINGERING INSTABILITY...OTHERWISE WE`RE PROBABLY
LOOKING AT A DECENT NIGHT. CONSIDERABLE CLOUDINESS EARLY.
FRIDAY AND SATURDAY...GENERAL NW FLOW ALOFT WEAK INSTABILITY
ASSOCIATED WITH THE TROUGH ALOFT AND MAYBE AN EMBEDDED SHORT
WAVE. NOTHING YET SEEN AS ORGANIZED ATTM AND SEEMS LIKE SCT AFTN
SHOWERS BOTH AFTERNOONS. WEST TO NORTHWEST WIND GUST 15 MPH EACH
AFTN.
SUNDAY...DRY AND NICE! LIGHT NW WIND.
MONDAY...DRY AND WARMER. VERY NICE! LIGHT SW WIND.
TUESDAY...THERE IS A CHANCE OF SHOWERS AND TSTMS MAINLY LATE AS A
COLD FRONT APPROACHES FROM THE NORTHWEST. WESTERLY WIND.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
CLOUDS WILL INCREASE THROUGH THE NIGHT AND LOWER, BUT VFR CONDITIONS
ARE EXPECTED THROUGH TONIGHT AND MOST OF THE DAY WEDNESDAY. THERE IS
A CHANCE OF SOME ISOLATED SHOWERS LATER THIS EVENING, ESPECIALLY
ACROSS THE NORTHERN TAFS, BUT CONFIDENCE WAS NOT HIGH ENOUGH TO
INCLUDE IN THE TAFS AT THIS TIME. MORE CONFIDENCE IN SHOWER ACTIVITY
IS DURING THE DAY WEDNESDAY, WHICH WAS INTRODUCED AT SOME TAF SITES.
THERE IS THE POSSIBILITY FOR SOME SCATTERED THUNDERSTORMS, BUT THEY
WERE NOT INCLUDED AT THIS TIME.
WINDS VARIED FROM SOUTHWEST, TO WEST, TO NORTHWEST LATE THIS
AFTERNOON, AVERAGING AROUND 10 KNOTS WITH SOME GUSTS IN THE MID TO
UPPER TEENS. THE GUSTS WILL DIMINISH IN THE NEXT FEW HOURS, AND
WINDS COULD BECOME LIGHT AND VARIABLE FOR A PERIOD OVERNIGHT, BEFORE
INCREASING OUT OF THE SOUTHEAST WEDNESDAY MORNING INTO THE DAY.
OUTLOOK...
WEDNESDAY NIGHT...LOCALIZED IFR VISIBILITIES INS SHOWERS AND POSSIBLE
TSTMS DURING THE EVENING. OTHERWISE MVFR CIGS AOA 3500 FT TO START
THE EVENING PROBABLY BECOMING WIDESPREAD IFR AND SPOTTY LIFR IN
ST/FOG WITH LIGHT WIND IN THE WEAK WARM FRONTAL WAVE BAGGY PRESSURE
GRADIENT...ESP S NJ AND DE. RIGHT NOW THE 09Z/20 SREF PROBS FOR
LOW CIGS/VSBY ARE MEAGER WITH GREATEST RISK OF LOW CIGS/VSBYS
ALONG AND N OF I78 (KABE NORTHWARD).
THURSDAY...GENERALLY VFR CONDITIONS EXPECTED AFTER EARLY MORNING
IFR ST/FOG LIFTS. LOCALIZED MVFR CONDITIONS ASSOCIATED WITH SCT AFTN
SHOWERS. LIGHT WIND. IFR PATCHY FOG POSSIBLE AT NIGHT.
FRIDAY AND SATURDAY...GENERALLY VFR CONDITIONS EXPECTED, WITH
LOCALIZED MVFR CONDITIONS POSSIBLE WITH ANY SHOWERS. SMALL RISK OF
AFTERNOON TSRA EACH DAY. WNW WIND EA AFTN GUSTING 15 KT.
SUNDAY...VFR. LIGHT NW WIND.
&&
.MARINE...
SUB-ADVISORY CONDITIONS WILL PREVAIL THROUGH WEDNESDAY AS A WARM FRONT
CONTINUES TO LIFT TOWARD THE AREA. WINDS MAY OCCASIONALLY GUST AROUND
20 KNOTS, ESPECIALLY LATER ON WEDNESDAY.
OUTLOOK...
WEDNESDAY NIGHT THROUGH SUNDAY...WINDS AND SEAS ARE EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY CONDITIONS THROUGH THIS PERIOD. AN EXCEPTION
MAY BE WEDNESDAY NIGHT IN THE NNJ WATERS WHERE THE NE WIND MAY FORCE
A SMALL PERIOD OF 5 FT SEAS LATE AT NIGHT IN ANZ450-451.
THERE IS SOME RISK OF FOG DEVELOPING LATE WEDNESDAY NIGHT AHEAD OF
AN APPROACHING COLD FRONT.
THIS IS SAFE BOATING WEEK AND PUBLIC INFORMATION STATEMENTS WERE
ISSUED YESTERDAY AT 1247Z AND TODAY AT 1048Z.
&&
.RIP CURRENTS...
THERE IS STILL A MODERATE RISK OF RIP CURRENTS ALONG THE NEW JERSEY
COAST LATE TODAY.
&&
.EQUIPMENT...
THE KDIX RADAR REMAINS OUT OF SERVICE. TECHNICIANS WILL BE WORKING
ON THE PROBLEM THIS EVENING.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DRAG 351
NEAR TERM...ROBERTSON 351
SHORT TERM...ROBERTSON 351
LONG TERM...DRAG 351
AVIATION...DRAG/ROBERTSON 351
MARINE...DRAG/ROBERTSON 351
RIP CURRENTS...351
EQUIPMENT...351
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
242 PM CDT TUE MAY 20 2014
.MESOSCALE DISCUSSION...
THE MAIN FOCUS THIS AFTERNOON WILL BE TIMING THE INITIATION OF
CONVECTION LATER THIS AFTERNOON AND EVENING ACROSS THE AREA.
STRONG TO SEVERE THUNDERSTORMS STILL APPEAR TO BE IN THE WORKS FOR
PORTIONS OF THE AREA LATER TODAY AND ESPECIALLY THIS EVENING WITHIN
THE VICINITY OF SLOW MOVING COOL FRONTAL BOUNDARY. THIS COOL FRONTAL
BOUNDARY IS CURRENTLY LOCATED FROM NORTHEASTERN IOWA...WEST
SOUTHWESTWARD ACROSS KANSAS. THE AIRMASS AHEAD OF THIS BOUNDARY
FEATURES DEWPOINTS MAINLY IN THE LOWER 60S...WITH TEMPERATURES
NEARING 80 DEGREES AS OF THE NOON HOUR UNDER SUNNY SKIES.
WATER VAPOR IMAGERY THIS MORNING INDICATES THE PRESENCE OF A
BROAD MID LEVEL RIDGE ACROSS THE CENTRAL STATES WEDGED BETWEEN
TWO UPPER LOWS/TROUGHS OVER EAST COAST. THIS IS DRIVING THE MAIN
BELT OF MID/UPPER WESTERLIES RIGHT ACROSS THE UPPER MIDWEST AND
GREAT LAKES REGION. THE MORNING RAOBS INDICATED THAT NORTHERN
ILLINOIS WAS ALONG THE SOUTHERN PERIPHERY OF THIS STRONGER MID/UPPER
LEVEL FLOW. SEVERAL SMALL SCALE DISTURBANCES...CURRENTLY NOTED IN
THE WATER VAPOR IMAGERY ACROSS NEBRASKA AND INTO WESTERN IOWA...WILL
BE OF INTEREST LATER THIS AFTERNOON AS THEY SHIFT EASTWARD TOWARDS
THE INCREASINGLY UNSTABLE ENVIRONMENT DEVELOPING ACROSS THE AREA.
IT APPEARS THAT STORMS MAY BEGIN TO INITIATE OVER THE NEXT FEW HOURS
ACROSS PORTIONS OF SOUTHERN IOWA...WHERE BETTER LOWER LEVEL
CONVERGENCE IS OCCURRING ALONG THE BOUNDARY. THIS ACTIVITY WOULD
LIKELY SHIFT/DEVELOP EASTWARD ACROSS NORTHERN ILLINOIS BY EARLY THIS
EVENING. ADDITIONAL STORMS MAY ALSO DEVELOP ACROSS SOUTHEASTERN
WI...WHERE THE LATEST VIS SAT IMAGERY INDICATES SOME CU FIRING ALONG
A LAKE BREEZE BOUNDARY. THE RAP SUGGESTS THAT STORM DEVELOPMENT
HERE COULD DRIVE A BOUNDARY SOUTH ACROSS NORTHEASTERN ILLINOIS...IN
WHICH STORMS WOULD DEVELOP. EITHER WAY...MUCH OF THE HIRES GUIDANCE
SUGGESTS THAT THUNDERSTORM ACTIVITY WILL BEGIN TO IMPACT NORTHERN
ILLINOIS BY THIS EVENING..LIKELY AFTER 5 PM. THE PRESENCE OF VERY
STEEP MID LEVEL LAPSE RATES...7+C/KM...PER 12 UTC RAOBS...ALONG WITH
THE POTENTIAL OF SUPERCELLS GIVEN THE DEEP LAYER
SHEAR...CERTAINLY SUGGESTS THAT VERY LARGE HAIL WILL BE A THREAT
WITH THESE STORMS TONIGHT. THERE IS ALSO THE THREAT OF STRONG
DAMAGING WINDS THIS EVENING...ESPECIALLY IF THE CONVECTIVE
ACTIVITY CONGEALS INTO A FORWARD PROPAGATING MCS.
ALTHOUGH THE ATMOSPHERE IS NOT OVERLY MOIST...PRECIPITABLE WATER
VALUES ARE PROGGED TO APPROACH 1.5 INCHES BY THIS EVENING.
IN ADDITION...THE DEEP LAYER WIND FIELDS SUGGEST THAT STORM
MOTIONS WILL BE MAINLY FROM WEST TO EAST...WHICH COULD RESULT IN SOME
TRAINING OF CELLS OVER THE SAME AREAS ACROSS NORTHERN ILLINOIS INTO
THIS EVENING. THIS RAISES SOME CONCERNS FOR SOME HEAVY RAINFALL
POTENTIAL IN ADDITION TO THE SEVERE THREAT THIS EVENING. AS A RESULT
OF THIS...THERE IS APPEARS TO BE A CONDITIONAL THREAT FOR SOME
ISOLATED AREAS EXCEEDING FLASH FLOOD GUIDANCE.
KJB
&&
.DISCUSSION...
333 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...PRIMARILY ALL
WITHIN THE FIRST 48 HOURS...AND PARTICULARLY THE THUNDERSTORM
CHANCES/COVERAGE THIS AFTERNOON AND TONIGHT. WITH THAT WILL BE A
CHANCE FOR ORGANIZED STORMS CAPABLE OF A SEVERE THREAT...WITH THE
GREATER THREAT ALONG AND NORTH OF INTERSTATE 80.
SYNOPSIS...
THE UPPER LEVEL RIDGE RESPONSIBLE FOR THE PRIMARILY NICE
PAST COUPLE DAYS HAS DAMPENED SOME IN RESPONSE TO STRONG JET STREAK
AND ASSOCIATED LOW AMPLITUDE IMPULSES RIDING ITS NORTHERN EDGE.
AS A CLOSED UPPER LOW NEAR LAKE WINNIPEG MOVES EAST TO THE
NORTHERN GREAT LAKES TONIGHT...FURTHER DAMPENING WILL OCCUR AND
THE INCREASED UPPER/MID LEVEL FLOW WILL DROP SOUTHWARD...CLOSER TO
OVER THE FORECAST AREA. A SURFACE FRONT WILL SLOWLY EASE INTO THE
AREA TONIGHT AND THEN SLOWLY THROUGH THE FORECAST AREA BY LATE IN
THE DAY WEDNESDAY. BEHIND THIS HIGH PRESSURE IS EXPECTED TO BRING
VERY PLEASANT WEATHER INTO AT LEAST THE FIRST HALF OF THE HOLIDAY
WEEKEND.
TODAY AND TONIGHT...
OUTSIDE OF POSSIBLY SOME EARLY MORNING SPRINKLES...THROUGH 3 PM LOOKS
MAINLY QUIET ACROSS THE FORECAST AREA. CLOUD COVER ASSOCIATED WITH
LAST NIGHTS LOW-LEVEL JET HAS ALREADY BEGUN TO MOVE EAST EARLY THIS
MORNING AND SHOULD CONTINUE. WHILE SOME HIGH DEBRIS CLOUDS WILL
DRIFT OVER THIS MORNING...IT IS EXPECTED TO DO LITTLE TO LIMIT
AGGRESSIVE WARMING TODAY. UPSTREAM OBSERVED TEMPERATURES YESTERDAY
AND CLIMATOLOGY FOR 850MB TEMPERATURES OF 14-16C IN LATE MAY
SUPPORT MID 80S FOR HIGHS. DEW POINTS...WHICH ARE THE KEY FACTOR
TO TODAYS AMOUNT OF INSTABILITY AND TIMING OF CAP BREAKING...ARE
FAVORED TO BE IN THE LOWER TO POOLED MID 60S ALONG THE FRONT.
THIS IS SUPPORTED BY UPSTREAM OBSERVATIONS WITHIN THE WARM SECTOR.
CONVECTIVE TEMPERATURES THEREFORE LOOK TO BE IN THE LOWER 80S IN
THE NORTHERN FORECAST AREA. HAVE LEANED AWAY FROM THE SLIGHTLY
MORE ROBUST AND QUICKLY INITIATING PAST 12KM NAM RUNS...WHICH
SEEMED INFLUENCE BY TOO HIGH OF BOUNDARY LAYER DEW POINTS. HAVE
LEANED THE FORECAST MORE WITH THE EC/GFS AS WELL AS MULTIPLE
CONVECTIVE ALLOWING MODELS /INCLUDING THE NAMS 4 KM RUN/...WHICH
SUPPORT MAINLY A LATE AFTERNOON DEVELOPMENT AND COVERAGE
INCREASING RAPIDLY 7-10 PM ACROSS NORTHERN IL.
WITH THE SURFACE LOW MOVING VERY SLOWLY ALONG THE INTERNATIONAL
BORDER THIS AFTERNOON...THE BOUNDARY WILL EASE IN SPEED WITH
CONVERGENCE WEAKENING...THOUGH STILL ENOUGH IN THE BOUNDARY LAYER
FOR A FOCUS. THE SECOND KEY IMPETUS LOOKS TO BE A MID-LEVEL SPEED
MAX AROUND 60KT PROJECTED TO EVOLVE OVER THE BOUNDARY IN SOUTHERN
WI/FAR NORTHERN IL LATE THIS AFTERNOON AND INTO EVE. THIS WILL ACT
TO WEAKEN ANY REMAINING CAP...SO EVEN IF CONVECTIVE TEMPERATURES
ARE NOT REACHED DURING PEAK HITTING...THIS SHOULD BE ENOUGH FOR
STORM DEVELOPMENT...THOUGH COVERAGE MAY BE ONLY SCATTERED PRIOR
TO SUNSET. THESE INCREASING MID-LEVEL WINDS WILL ALSO SUPPORT
REGENERATING AS WELL AS SUSTAINED CONVECTIVE CLUSTERS TONIGHT THAT
ARE FAVORED TO EVOLVE EAST SOUTHEAST WITH THE PRIMARILY STEERING
FLOW. THE CHICAGO AREA LOOKS TO MOST LIKELY SEE STORMS IN THE
EVENING PERIOD. /7 PM-12 AM/
FORECAST VALUES WITHIN THE INSTABILITY/SHEAR SPECTRUM ARE CERTAINLY
ENOUGH TO SUPPORT SEVERE STORMS LATE THIS AFTERNOON AND INTO
TONIGHT. CONCEPTUALLY...BEING AT THE EDGE OF THE ELEVATED MIXED
LAYER...WHICH IS FORECAST TO HAVE LAPSE RATES OF 8.5-9 C/KM...THE
POTENTIAL FOR LARGE HAIL EXISTS. THE 00Z EC DOES SUPPORT 500-800
J/KG OF -10C TO -30C CAPE...WHICH ADDS A CONDITIONAL THREAT FOR
POSSIBLY GOLF BALL OR LARGER HAIL...PRIMARILY WITH ANY STORMS THIS
AFTERNOON THROUGH MID-EVE...AS THEY ARE MORE LIKELY TO BE
DISCRETE. THOUGH AGAIN...COVERAGE OF THIS MAY BE QUITE LIMITED.
THE PRECISE MODE OF CONVECTION AND HOW FAR SOUTH IT MOVES TONIGHT
REMAINS UNCERTAIN...BUT HAVE KEPT THE IDEA THAT MORE OF THE
PROBABLE WELL-ORGANIZED CLUSTERS CAPABLE OF HAIL/WIND WOULD BE
FAVORED NORTH OF INTERSTATE 80...WHERE DEEP LAYER SHEAR IS
STRONGER AND EAST-ORIENTED VECTORS SUPPORT SUSTAINED CONVECTION
QUICKLY MOVING MORE EAST THAN SOUTH.
DID ADD THE MENTION OF PATCHY FOG LATE TONIGHT...GIVEN LIGHT WINDS
ALONG THE BOUNDARY AND CONVECTIVELY COOLED AIR IN PLACES WITH
LINGERING HIGH DEW POINTS. ITS CONCEIVABLE DENSE FOG COULD OCCUR
AND POSSIBLY BE SEEN AFTER DAYBREAK WEDNESDAY.
WEDNESDAY...
SOME FESTERING SHOWERS/STORMS MAY EXIST AROUND OR SOUTH OF THE
INTERSTATE 80 CORRIDOR IN THE EARLY MORNING...BUT THE FOCUS FOR
CONVECTION WOULD LIKELY BE AS CONVERGENCE ALONG THE FRONT IN THE
AFTERNOON. AN EARLIER INITIATION SHOULD OCCUR WEDNESDAY AFTERNOON
ALONG THIS BOUNDARY WITH SLIGHTLY HIGHER DEW POINTS AND
STRENGTHENING CONVERGENCE. QUITE A BIT OF SPREAD ON WHERE EXACTLY
THAT BOUNDARY IS. CONVECTION TONIGHT WILL CERTAINLY HAVE AN IMPACT
ON THAT. THE SPC SLIGHT RISK FOR DAY 2 INCLUDES THE FAR SOUTHEAST
WHICH SEEMS REASONABLE AND HAVE MAINLY KEPT FORECAST ON TRACK WITH
THAT. TEMPERATURES AREA WIDE ON WEDNESDAY LOOK TO BE VERY
MILD...WITH MID 80S PLAUSIBLE IN MOST AREAS /EXCEPTION WOULD BE
NORTHWEST INDIANA WITH ONSHORE FLOW/.
THURSDAY AND BEYOND...
FEW CHANGES MADE TO THIS PORTION OF THE FORECAST WITH FOCUS ON THE
SHORT TERM. AS PREVIOUS SHIFT DID...CONTINUE TO LEAN TOWARD SLOWER
GUIDANCE IN EVOLUTION OF THE NEXT CHANCE OF RAIN...WHICH MAY BE
MEMORIAL DAY...ALTHOUGH THE STRENGTH OF THE RIDGING ON ALL
GUIDANCE IS PRETTY IMPRESSIVE. THIS LOOKS TO SUPPORT TEMPERATURES
IN THE 80S ON THE HOLIDAY THAT OFFICIALLY KICKS OFF A LONG-AWAITED
SUMMER.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* TSRA POTENTIAL EARLY THIS EVENING.
* POTENTIAL FOR MVFR VSBY AND CIGS LATE TONIGHT INTO EARLY
WEDNESDAY.
* SWLY WINDS GUSTING TO 20 KT THROUGH THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
PRIMARY CONCERN FOR THE PERIOD WILL BE NARROWING DOWN THE TIMING
OF THE MOST LIKELY THUNDERSTORM POTENTIAL AND THEN FOLLOWED BY A
PERIOD OF LINGERING SHOWERS WITH SOME MVFR POTENTIAL FOR THE EARLY
MORNING HOURS.
FOR THE REMAINDER OF THE AFTERNOON...CONDITIONS SHOULD BE
UNRESTRICTED WITH SWLY WINDS OCNLY GUSTING IN THE UPPER TEENS.
DAYTIME MIXING WILL LARGELY DRIVE THE TIMING OF GENERAL
GUSTINESS...SO EXPECT THE GUSTS TO SETTLE AT SUNSET...OUTSIDE OF
THUNDERSTORMS.
AS FOR THE THUNDERSTORMS FORECAST...THE LATEST HIGH RES GUIDANCE
CONTINUES TO INDICATE THE BEST THUNDERSTORM POTENTIAL TO INITIAL
IN SRN WISCONSIN LATE THIS AFTERNOON AND THEN SLOWLY SAG SWD INTO
NRN IL DURG THE EARLY EVENING HOURS. GIVEN THE UNCERTAINTY IN
TIMING STILL AT THIS POINT...HAVE MAINTAINED THE GOING TIMING IN
THE TEMPO GROUP...BUT FEEL THAT LATER UPDATES WILL TRY TO NARROW
DOWN A PERIOD OF PREVAILING TS...BUT THAT WILL BE HIGHLY DEPENDENT
ON THE SPEED WITH WHICH THE FRONT SAGS SOUTH. THE OTHER CAVEAT FOR
THE THUNDER TIMING AT THE TERMINALS WILL BE THE SEVERE POTENTIAL
AND THE CONVECTIVE MODE OF SEVERE TS. IF THE CONVECTIVE MODE IS
STILL DISCRETE CELLS AT THE TIME TS IS INVOF THE TERMINALS...THEN
A PREVAILING TIMING WILL BE DIFFICULT TO DETERMINE. IF CONVECTIVE
MODE TRANSITIONS TO LINEAR...THEN A PREVAILING TIMING WILL BE MORE
CERTAIN.
FOLLOWING THE PASSAGE OF THE MAIN CONVECTIVE ACTIVITY...THERE
SHOULD BE A PERIOD OF TRAILING SHOWERS...AND WITH AMPLE MOISTURE
IN PLACE...MVFR CONDITIONS ARE LIKELY THROUGH AT LEAST DAYBREAK.
DAYTIME WARMING SHOULD HELP BREAK UP THE CLOUD COVER...AND THEN ANY
BR SHOULD IMPROVE BY LATE MORNING. THE REMAINDER OF WEDNESDAY
SHOULD BE QUIET...WITH VFR CONDITIONS AND WX/NIL.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH CONFIDENCE IN TSRA DIRECTLY IMPACTING TERMINALS THIS
EVENING...LOW CONFIDENCE IN EXACT TIMING AND DURATION OF DIRECT
IMPACTS TO TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS UNTIL LIKELY IMPACTS FROM
TSRA THIS EVENING.
* LOW-MEDIUM CONFIDENCE IN REDUCED VSBY/CIG POTENTIAL LATE
TONIGHT INTO EARLY WEDNESDAY.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY AND FRIDAY...VFR WITH LAKE BREEZE WIND SHIFT LIKELY.
SATURDAY...VFR WITH EAST-NORTHEAST WINDS.
SUNDAY...VFR. SOUTH-SOUTHEAST WINDS POSSIBLY BACKING EAST-SOUTHEAST.
MONDAY...VFR THEN CHANCE AFTERNOON TSRA.
RC
&&
.MARINE...
216 PM CDT
LOW PRESSURE ACROSS NORTHERN MINNESOTA IS LIFTING A WARM FRONTAL
BOUNDARY NORTHWARD ACROSS THE LAKE THIS AFTERNOON. IN THE WAKE OF
THIS BOUNDARY...A WARM AND MOIST AIRMASS IS LIFTING NORTHWARD ACROSS
THE COOL LAKE WATERS. THIS WILL INCREASE THE THREAT FOR FOG ACROSS
THE LAKE TONIGHT. OTHERWISE...THE MAIN THREAT TONIGHT...MAINLY
ACROSS THE SOUTHERN PORTION OF THE LAKE WILL BE STRONG TO SEVERE
THUNDERSTORMS. THE ATMOSPHERE WILL BE SUPPORTIVE OF STORMS CAPABLE
OF PRODUCING WINDS IN EXCESS OF 50 KT AND LARGE HAIL. THE MAIN
THREAT LOOKS TO BE THIS EVENING.
HIGH PRESSURE WILL GRADUALLY BUILD SOUTHEASTWARD OVER THE LAKE BY
FRIDAY. A PERIOD OF NORTHERLY WINDS ARE LIKELY PRIOR TO THE ARRIVAL
OF THE SURFACE HIGH. HOWEVER...WINDS ARE EXPECTED TO SHIFT BACK OUT
OF THE SOUTH AND WILL LIKELY INCREASE SOME LATER IN THE WEEKEND INTO
EARLY NEXT WEEK AS THE SURFACE HIGH SHIFTS EASTWARD ACROSS THE OHIO
VALLEY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
216 PM CDT TUE MAY 20 2014
.MESOSCALE DISCUSSION...110 PM CDT
THE MAIN FOCUS THIS AFTERNOON WILL BE TIMING THE INITIATION OF
CONVECTION LATER THIS AFTERNOON AND EVENING ACROSS THE AREA.
STRONG TO SEVERE THUNDERSTORMS STILL APPEAR TO BE IN THE WORKS FOR
PORTIONS OF THE AREA LATER TODAY AND ESPECIALLY THIS EVENING WITHIN
THE VICINITY OF SLOW MOVING COOL FRONTAL BOUNDARY. THIS COOL FRONTAL
BOUNDARY IS CURRENTLY LOCATED FROM NORTHEASTERN IOWA...WEST
SOUTHWESTWARD ACROSS KANSAS. THE AIRMASS AHEAD OF THIS BOUNDARY
FEATURES DEWPOINTS MAINLY IN THE LOWER 60S...WITH TEMPERATURES
NEARING 80 DEGREES AS OF THE NOON HOUR UNDER SUNNY SKIES.
WATER VAPOR IMAGERY THIS MORNING INDICATES THE PRESENCE OF A
BROAD MID LEVEL RIDGE ACROSS THE CENTRAL STATES WEDGED BETWEEN
TWO UPPER LOWS/TROUGHS OVER EAST COAST. THIS IS DRIVING THE MAIN
BELT OF MID/UPPER WESTERLIES RIGHT ACROSS THE UPPER MIDWEST AND
GREAT LAKES REGION. THE MORNING RAOBS INDICATED THAT NORTHERN
ILLINOIS WAS ALONG THE SOUTHERN PERIPHERY OF THIS STRONGER MID/UPPER
LEVEL FLOW. SEVERAL SMALL SCALE DISTURBANCES...CURRENTLY NOTED IN
THE WATER VAPOR IMAGERY ACROSS NEBRASKA AND INTO WESTERN IOWA...WILL
BE OF INTEREST LATER THIS AFTERNOON AS THEY SHIFT EASTWARD TOWARDS
THE INCREASINGLY UNSTABLE ENVIRONMENT DEVELOPING ACROSS THE AREA.
IT APPEARS THAT STORMS MAY BEGIN TO INITIATE OVER THE NEXT FEW HOURS
ACROSS PORTIONS OF SOUTHERN IOWA...WHERE BETTER LOWER LEVEL
CONVERGENCE IS OCCURRING ALONG THE BOUNDARY. THIS ACTIVITY WOULD
LIKELY SHIFT/DEVELOP EASTWARD ACROSS NORTHERN ILLINOIS BY EARLY THIS
EVENING. ADDITIONAL STORMS MAY ALSO DEVELOP ACROSS SOUTHEASTERN
WI...WHERE THE LATEST VIS SAT IMAGERY INDICATES SOME CU FIRING ALONG
A LAKE BREEZE BOUNDARY. THE RAP SUGGESTS THAT STORM DEVELOPMENT
HERE COULD DRIVE A BOUNDARY SOUTH ACROSS NORTHEASTERN ILLINOIS...IN
WHICH STORMS WOULD DEVELOP. EITHER WAY...MUCH OF THE HIRES GUIDANCE
SUGGESTS THAT THUNDERSTORM ACTIVITY WILL BEGIN TO IMPACT NORTHERN
ILLINOIS BY THIS EVENING..LIKELY AFTER 5 PM. THE PRESENCE OF VERY
STEEP MID LEVEL LAPSE RATES...7+C/KM...PER 12 UTC RAOBS...ALONG WITH
THE POTENTIAL OF SUPERCELLS GIVEN THE DEEP LAYER
SHEAR...CERTAINLY SUGGESTS THAT VERY LARGE HAIL WILL BE A THREAT
WITH THESE STORMS TONIGHT. THERE IS ALSO THE THREAT OF STRONG
DAMAGING WINDS THIS EVENING...ESPECIALLY IF THE CONVECTIVE
ACTIVITY CONGEALS INTO A FORWARD PROPAGATING MCS.
ALTHOUGH THE ATMOSPHERE IS NOT OVERLY MOIST...PRECIPITABLE WATER
VALUES ARE PROGGED TO APPROACH 1.5 INCHES BY THIS EVENING.
IN ADDITION...THE DEEP LAYER WIND FIELDS SUGGEST THAT STORM
MOTIONS WILL BE MAINLY FROM WEST TO EAST...WHICH COULD RESULT IN SOME
TRAINING OF CELLS OVER THE SAME AREAS ACROSS NORTHERN ILLINOIS INTO
THIS EVENING. THIS RAISES SOME CONCERNS FOR SOME HEAVY RAINFALL
POTENTIAL IN ADDITION TO THE SEVERE THREAT THIS EVENING. AS A RESULT
OF THIS...THERE IS APPEARS TO BE A CONDITIONAL THREAT FOR SOME
ISOLATED AREAS EXCEEDING FLASH FLOOD GUIDANCE.
KJB
&&
.DISCUSSION...
333 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...PRIMARILY ALL
WITHIN THE FIRST 48 HOURS...AND PARTICULARLY THE THUNDERSTORM
CHANCES/COVERAGE THIS AFTERNOON AND TONIGHT. WITH THAT WILL BE A
CHANCE FOR ORGANIZED STORMS CAPABLE OF A SEVERE THREAT...WITH THE
GREATER THREAT ALONG AND NORTH OF INTERSTATE 80.
SYNOPSIS...
THE UPPER LEVEL RIDGE RESPONSIBLE FOR THE PRIMARILY NICE
PAST COUPLE DAYS HAS DAMPENED SOME IN RESPONSE TO STRONG JET STREAK
AND ASSOCIATED LOW AMPLITUDE IMPULSES RIDING ITS NORTHERN EDGE.
AS A CLOSED UPPER LOW NEAR LAKE WINNIPEG MOVES EAST TO THE
NORTHERN GREAT LAKES TONIGHT...FURTHER DAMPENING WILL OCCUR AND
THE INCREASED UPPER/MID LEVEL FLOW WILL DROP SOUTHWARD...CLOSER TO
OVER THE FORECAST AREA. A SURFACE FRONT WILL SLOWLY EASE INTO THE
AREA TONIGHT AND THEN SLOWLY THROUGH THE FORECAST AREA BY LATE IN
THE DAY WEDNESDAY. BEHIND THIS HIGH PRESSURE IS EXPECTED TO BRING
VERY PLEASANT WEATHER INTO AT LEAST THE FIRST HALF OF THE HOLIDAY
WEEKEND.
TODAY AND TONIGHT...
OUTSIDE OF POSSIBLY SOME EARLY MORNING SPRINKLES...THROUGH 3 PM LOOKS
MAINLY QUIET ACROSS THE FORECAST AREA. CLOUD COVER ASSOCIATED WITH
LAST NIGHTS LOW-LEVEL JET HAS ALREADY BEGUN TO MOVE EAST EARLY THIS
MORNING AND SHOULD CONTINUE. WHILE SOME HIGH DEBRIS CLOUDS WILL
DRIFT OVER THIS MORNING...IT IS EXPECTED TO DO LITTLE TO LIMIT
AGGRESSIVE WARMING TODAY. UPSTREAM OBSERVED TEMPERATURES YESTERDAY
AND CLIMATOLOGY FOR 850MB TEMPERATURES OF 14-16C IN LATE MAY
SUPPORT MID 80S FOR HIGHS. DEW POINTS...WHICH ARE THE KEY FACTOR
TO TODAYS AMOUNT OF INSTABILITY AND TIMING OF CAP BREAKING...ARE
FAVORED TO BE IN THE LOWER TO POOLED MID 60S ALONG THE FRONT.
THIS IS SUPPORTED BY UPSTREAM OBSERVATIONS WITHIN THE WARM SECTOR.
CONVECTIVE TEMPERATURES THEREFORE LOOK TO BE IN THE LOWER 80S IN
THE NORTHERN FORECAST AREA. HAVE LEANED AWAY FROM THE SLIGHTLY
MORE ROBUST AND QUICKLY INITIATING PAST 12KM NAM RUNS...WHICH
SEEMED INFLUENCE BY TOO HIGH OF BOUNDARY LAYER DEW POINTS. HAVE
LEANED THE FORECAST MORE WITH THE EC/GFS AS WELL AS MULTIPLE
CONVECTIVE ALLOWING MODELS /INCLUDING THE NAMS 4 KM RUN/...WHICH
SUPPORT MAINLY A LATE AFTERNOON DEVELOPMENT AND COVERAGE
INCREASING RAPIDLY 7-10 PM ACROSS NORTHERN IL.
WITH THE SURFACE LOW MOVING VERY SLOWLY ALONG THE INTERNATIONAL
BORDER THIS AFTERNOON...THE BOUNDARY WILL EASE IN SPEED WITH
CONVERGENCE WEAKENING...THOUGH STILL ENOUGH IN THE BOUNDARY LAYER
FOR A FOCUS. THE SECOND KEY IMPETUS LOOKS TO BE A MID-LEVEL SPEED
MAX AROUND 60KT PROJECTED TO EVOLVE OVER THE BOUNDARY IN SOUTHERN
WI/FAR NORTHERN IL LATE THIS AFTERNOON AND INTO EVE. THIS WILL ACT
TO WEAKEN ANY REMAINING CAP...SO EVEN IF CONVECTIVE TEMPERATURES
ARE NOT REACHED DURING PEAK HITTING...THIS SHOULD BE ENOUGH FOR
STORM DEVELOPMENT...THOUGH COVERAGE MAY BE ONLY SCATTERED PRIOR
TO SUNSET. THESE INCREASING MID-LEVEL WINDS WILL ALSO SUPPORT
REGENERATING AS WELL AS SUSTAINED CONVECTIVE CLUSTERS TONIGHT THAT
ARE FAVORED TO EVOLVE EAST SOUTHEAST WITH THE PRIMARILY STEERING
FLOW. THE CHICAGO AREA LOOKS TO MOST LIKELY SEE STORMS IN THE
EVENING PERIOD. /7 PM-12 AM/
FORECAST VALUES WITHIN THE INSTABILITY/SHEAR SPECTRUM ARE CERTAINLY
ENOUGH TO SUPPORT SEVERE STORMS LATE THIS AFTERNOON AND INTO
TONIGHT. CONCEPTUALLY...BEING AT THE EDGE OF THE ELEVATED MIXED
LAYER...WHICH IS FORECAST TO HAVE LAPSE RATES OF 8.5-9 C/KM...THE
POTENTIAL FOR LARGE HAIL EXISTS. THE 00Z EC DOES SUPPORT 500-800
J/KG OF -10C TO -30C CAPE...WHICH ADDS A CONDITIONAL THREAT FOR
POSSIBLY GOLF BALL OR LARGER HAIL...PRIMARILY WITH ANY STORMS THIS
AFTERNOON THROUGH MID-EVE...AS THEY ARE MORE LIKELY TO BE
DISCRETE. THOUGH AGAIN...COVERAGE OF THIS MAY BE QUITE LIMITED.
THE PRECISE MODE OF CONVECTION AND HOW FAR SOUTH IT MOVES TONIGHT
REMAINS UNCERTAIN...BUT HAVE KEPT THE IDEA THAT MORE OF THE
PROBABLE WELL-ORGANIZED CLUSTERS CAPABLE OF HAIL/WIND WOULD BE
FAVORED NORTH OF INTERSTATE 80...WHERE DEEP LAYER SHEAR IS
STRONGER AND EAST-ORIENTED VECTORS SUPPORT SUSTAINED CONVECTION
QUICKLY MOVING MORE EAST THAN SOUTH.
DID ADD THE MENTION OF PATCHY FOG LATE TONIGHT...GIVEN LIGHT WINDS
ALONG THE BOUNDARY AND CONVECTIVELY COOLED AIR IN PLACES WITH
LINGERING HIGH DEW POINTS. ITS CONCEIVABLE DENSE FOG COULD OCCUR
AND POSSIBLY BE SEEN AFTER DAYBREAK WEDNESDAY.
WEDNESDAY...
SOME FESTERING SHOWERS/STORMS MAY EXIST AROUND OR SOUTH OF THE
INTERSTATE 80 CORRIDOR IN THE EARLY MORNING...BUT THE FOCUS FOR
CONVECTION WOULD LIKELY BE AS CONVERGENCE ALONG THE FRONT IN THE
AFTERNOON. AN EARLIER INITIATION SHOULD OCCUR WEDNESDAY AFTERNOON
ALONG THIS BOUNDARY WITH SLIGHTLY HIGHER DEW POINTS AND
STRENGTHENING CONVERGENCE. QUITE A BIT OF SPREAD ON WHERE EXACTLY
THAT BOUNDARY IS. CONVECTION TONIGHT WILL CERTAINLY HAVE AN IMPACT
ON THAT. THE SPC SLIGHT RISK FOR DAY 2 INCLUDES THE FAR SOUTHEAST
WHICH SEEMS REASONABLE AND HAVE MAINLY KEPT FORECAST ON TRACK WITH
THAT. TEMPERATURES AREA WIDE ON WEDNESDAY LOOK TO BE VERY
MILD...WITH MID 80S PLAUSIBLE IN MOST AREAS /EXCEPTION WOULD BE
NORTHWEST INDIANA WITH ONSHORE FLOW/.
THURSDAY AND BEYOND...
FEW CHANGES MADE TO THIS PORTION OF THE FORECAST WITH FOCUS ON THE
SHORT TERM. AS PREVIOUS SHIFT DID...CONTINUE TO LEAN TOWARD SLOWER
GUIDANCE IN EVOLUTION OF THE NEXT CHANCE OF RAIN...WHICH MAY BE
MEMORIAL DAY...ALTHOUGH THE STRENGTH OF THE RIDGING ON ALL
GUIDANCE IS PRETTY IMPRESSIVE. THIS LOOKS TO SUPPORT TEMPERATURES
IN THE 80S ON THE HOLIDAY THAT OFFICIALLY KICKS OFF A LONG-AWAITED
SUMMER.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* TSRA POTENTIAL EARLY THIS EVENING.
* POTENTIAL FOR MVFR VSBY AND CIGS LATE TONIGHT INTO EARLY
WEDNESDAY.
* SWLY WINDS GUSTING TO 20 KT THROUGH THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
PRIMARY CONCERN FOR THE PERIOD WILL BE NARROWING DOWN THE TIMING
OF THE MOST LIKELY THUNDERSTORM POTENTIAL AND THEN FOLLOWED BY A
PERIOD OF LINGERING SHOWERS WITH SOME MVFR POTENTIAL FOR THE EARLY
MORNING HOURS.
FOR THE REMAINDER OF THE AFTERNOON...CONDITIONS SHOULD BE
UNRESTRICTED WITH SWLY WINDS OCNLY GUSTING IN THE UPPER TEENS.
DAYTIME MIXING WILL LARGELY DRIVE THE TIMING OF GENERAL
GUSTINESS...SO EXPECT THE GUSTS TO SETTLE AT SUNSET...OUTSIDE OF
THUNDERSTORMS.
AS FOR THE THUNDERSTORMS FORECAST...THE LATEST HIGH RES GUIDANCE
CONTINUES TO INDICATE THE BEST THUNDERSTORM POTENTIAL TO INITIAL
IN SRN WISCONSIN LATE THIS AFTERNOON AND THEN SLOWLY SAG SWD INTO
NRN IL DURG THE EARLY EVENING HOURS. GIVEN THE UNCERTAINTY IN
TIMING STILL AT THIS POINT...HAVE MAINTAINED THE GOING TIMING IN
THE TEMPO GROUP...BUT FEEL THAT LATER UPDATES WILL TRY TO NARROW
DOWN A PERIOD OF PREVAILING TS...BUT THAT WILL BE HIGHLY DEPENDENT
ON THE SPEED WITH WHICH THE FRONT SAGS SOUTH. THE OTHER CAVEAT FOR
THE THUNDER TIMING AT THE TERMINALS WILL BE THE SEVERE POTENTIAL
AND THE CONVECTIVE MODE OF SEVERE TS. IF THE CONVECTIVE MODE IS
STILL DISCRETE CELLS AT THE TIME TS IS INVOF THE TERMINALS...THEN
A PREVAILING TIMING WILL BE DIFFICULT TO DETERMINE. IF CONVECTIVE
MODE TRANSITIONS TO LINEAR...THEN A PREVAILING TIMING WILL BE MORE
CERTAIN.
FOLLOWING THE PASSAGE OF THE MAIN CONVECTIVE ACTIVITY...THERE
SHOULD BE A PERIOD OF TRAILING SHOWERS...AND WITH AMPLE MOISTURE
IN PLACE...MVFR CONDITIONS ARE LIKELY THROUGH AT LEAST DAYBREAK.
DAYTIME WARMING SHOULD HELP BREAK UP THE CLOUD COVER...AND THEN ANY
BR SHOULD IMPROVE BY LATE MORNING. THE REMAINDER OF WEDNESDAY
SHOULD BE QUIET...WITH VFR CONDITIONS AND WX/NIL.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH CONFIDENCE IN TSRA DIRECTLY IMPACTING TERMINALS THIS
EVENING...LOW CONFIDENCE IN EXACT TIMING AND DURATION OF DIRECT
IMPACTS TO TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS UNTIL LIKELY IMPACTS FROM
TSRA THIS EVENING.
* LOW-MEDIUM CONFIDENCE IN REDUCED VSBY/CIG POTENTIAL LATE
TONIGHT INTO EARLY WEDNESDAY.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY AND FRIDAY...VFR WITH LAKE BREEZE WIND SHIFT LIKELY.
SATURDAY...VFR WITH EAST-NORTHEAST WINDS.
SUNDAY...VFR. SOUTH-SOUTHEAST WINDS POSSIBLY BACKING EAST-SOUTHEAST.
MONDAY...VFR THEN CHANCE AFTERNOON TSRA.
RC
&&
.MARINE...
216 PM CDT
LOW PRESSURE ACROSS NORTHERN MINNESOTA IS LIFTING A WARM FRONTAL
BOUNDARY NORTHWARD ACROSS THE LAKE THIS AFTERNOON. IN THE WAKE OF
THIS BOUNDARY...A WARM AND MOIST AIRMASS IS LIFTING NORTHWARD ACROSS
THE COOL LAKE WATERS. THIS WILL INCREASE THE THREAT FOR FOG ACROSS
THE LAKE TONIGHT. OTHERWISE...THE MAIN THREAT TONIGHT...MAINLY
ACROSS THE SOUTHERN PORTION OF THE LAKE WILL BE STRONG TO SEVERE
THUNDERSTORMS. THE ATMOSPHERE WILL BE SUPPORTIVE OF STORMS CAPABLE
OF PRODUCING WINDS IN EXCESS OF 50 KT AND LARGE HAIL. THE MAIN
THREAT LOOKS TO BE THIS EVENING.
HIGH PRESSURE WILL GRADUALLY BUILD SOUTHEASTWARD OVER THE LAKE BY
FRIDAY. A PERIOD OF NORTHERLY WINDS ARE LIKELY PRIOR TO THE ARRIVAL
OF THE SURFACE HIGH. HOWEVER...WINDS ARE EXPECTED TO SHIFT BACK OUT
OF THE SOUTH AND WILL LIKELY INCREASE SOME LATER IN THE WEEKEND INTO
EARLY NEXT WEEK AS THE SURFACE HIGH SHIFTS EASTWARD ACROSS THE OHIO
VALLEY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
112 PM CDT TUE MAY 20 2014
.MESOSCALE DISCUSSION...
110 PM CDT
THE MAIN FOCUS THIS AFTERNOON WILL BE TIMING THE INITIATION OF
CONVECTION LATER THIS AFTERNOON AND EVENING ACROSS THE AREA.
STRONG TO SEVERE THUNDERSTORMS STILL APPEAR TO BE IN THE WORKS FOR
PORTIONS OF THE AREA LATER TODAY AND ESPECIALLY THIS EVENING WITHIN
THE VICINITY OF SLOW MOVING COOL FRONTAL BOUNDARY. THIS COOL FRONTAL
BOUNDARY IS CURRENTLY LOCATED FROM NORTHEASTERN IOWA...WEST
SOUTHWESTWARD ACROSS KANSAS. THE AIRMASS AHEAD OF THIS BOUNDARY
FEATURES DEWPOINTS MAINLY IN THE LOWER 60S...WITH TEMPERATURES
NEARING 80 DEGREES AS OF THE NOON HOUR UNDER SUNNY SKIES.
WATER VAPOR IMAGERY THIS MORNING INDICATES THE PRESENCE OF A
BROAD MID LEVEL RIDGE ACROSS THE CENTRAL STATES WEDGED BETWEEN
TWO UPPER LOWS/TROUGHS OVER EAST COAST. THIS IS DRIVING THE MAIN
BELT OF MID/UPPER WESTERLIES RIGHT ACROSS THE UPPER MIDWEST AND
GREAT LAKES REGION. THE MORNING RAOBS INDICATED THAT NORTHERN
ILLINOIS WAS ALONG THE SOUTHERN PERIPHERY OF THIS STRONGER MID/UPPER
LEVEL FLOW. SEVERAL SMALL SCALE DISTURBANCES...CURRENTLY NOTED IN
THE WATER VAPOR IMAGERY ACROSS NEBRASKA AND INTO WESTERN IOWA...WILL
BE OF INTEREST LATER THIS AFTERNOON AS THEY SHIFT EASTWARD TOWARDS
THE INCREASINGLY UNSTABLE ENVIRONMENT DEVELOPING ACROSS THE AREA.
IT APPEARS THAT STORMS MAY BEGIN TO INITIATE OVER THE NEXT FEW HOURS
ACROSS PORTIONS OF SOUTHERN IOWA...WHERE BETTER LOWER LEVEL
CONVERGENCE IS OCCURRING ALONG THE BOUNDARY. THIS ACTIVITY WOULD
LIKELY SHIFT/DEVELOP EASTWARD ACROSS NORTHERN ILLINOIS BY EARLY THIS
EVENING. ADDITIONAL STORMS MAY ALSO DEVELOP ACROSS SOUTHEASTERN
WI...WHERE THE LATEST VIS SAT IMAGERY INDICATES SOME CU FIRING ALONG
A LAKE BREEZE BOUNDARY. THE RAP SUGGESTS THAT STORM DEVELOPMENT
HERE COULD DRIVE A BOUNDARY SOUTH ACROSS NORTHEASTERN ILLINOIS...IN
WHICH STORMS WOULD DEVELOP. EITHER WAY...MUCH OF THE HIRES GUIDANCE
SUGGESTS THAT THUNDERSTORM ACTIVITY WILL BEGIN TO IMPACT NORTHERN
ILLINOIS BY THIS EVENING..LIKELY AFTER 5 PM. THE PRESENCE OF VERY
STEEP MID LEVEL LAPSE RATES...7+C/KM...PER 12 UTC RAOBS...ALONG WITH
THE POTENTIAL OF SUPERCELLS GIVEN THE DEEP LAYER
SHEAR...CERTAINLY SUGGESTS THAT VERY LARGE HAIL WILL BE A THREAT
WITH THESE STORMS TONIGHT. THERE IS ALSO THE THREAT OF STRONG
DAMAGING WINDS THIS EVENING...ESPECIALLY IF THE CONVECTIVE
ACTIVITY CONGEALS INTO A FORWARD PROPAGATING MCS.
ALTHOUGH THE ATMOSPHERE IS NOT OVERLY MOIST...PRECIPITABLE WATER
VALUES ARE PROGGED TO APPROACH 1.5 INCHES BY THIS EVENING.
IN ADDITION...THE DEEP LAYER WIND FIELDS SUGGEST THAT STORM
MOTIONS WILL BE MAINLY FROM WEST TO EAST...WHICH COULD RESULT IN SOME
TRAINING OF CELLS OVER THE SAME AREAS ACROSS NORTHERN ILLINOIS INTO
THIS EVENING. THIS RAISES SOME CONCERNS FOR SOME HEAVY RAINFALL
POTENTIAL IN ADDITION TO THE SEVERE THREAT THIS EVENING. AS A RESULT
OF THIS...THERE IS APPEARS TO BE A CONDITIONAL THREAT FOR SOME
ISOLATED AREAS EXCEEDING FLASH FLOOD GUIDANCE.
KJB
&&
.DISCUSSION...
333 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...PRIMARILY ALL
WITHIN THE FIRST 48 HOURS...AND PARTICULARLY THE THUNDERSTORM
CHANCES/COVERAGE THIS AFTERNOON AND TONIGHT. WITH THAT WILL BE A
CHANCE FOR ORGANIZED STORMS CAPABLE OF A SEVERE THREAT...WITH THE
GREATER THREAT ALONG AND NORTH OF INTERSTATE 80.
SYNOPSIS...
THE UPPER LEVEL RIDGE RESPONSIBLE FOR THE PRIMARILY NICE
PAST COUPLE DAYS HAS DAMPENED SOME IN RESPONSE TO STRONG JET STREAK
AND ASSOCIATED LOW AMPLITUDE IMPULSES RIDING ITS NORTHERN EDGE.
AS A CLOSED UPPER LOW NEAR LAKE WINNIPEG MOVES EAST TO THE
NORTHERN GREAT LAKES TONIGHT...FURTHER DAMPENING WILL OCCUR AND
THE INCREASED UPPER/MID LEVEL FLOW WILL DROP SOUTHWARD...CLOSER TO
OVER THE FORECAST AREA. A SURFACE FRONT WILL SLOWLY EASE INTO THE
AREA TONIGHT AND THEN SLOWLY THROUGH THE FORECAST AREA BY LATE IN
THE DAY WEDNESDAY. BEHIND THIS HIGH PRESSURE IS EXPECTED TO BRING
VERY PLEASANT WEATHER INTO AT LEAST THE FIRST HALF OF THE HOLIDAY
WEEKEND.
TODAY AND TONIGHT...
OUTSIDE OF POSSIBLY SOME EARLY MORNING SPRINKLES...THROUGH 3 PM LOOKS
MAINLY QUIET ACROSS THE FORECAST AREA. CLOUD COVER ASSOCIATED WITH
LAST NIGHTS LOW-LEVEL JET HAS ALREADY BEGUN TO MOVE EAST EARLY THIS
MORNING AND SHOULD CONTINUE. WHILE SOME HIGH DEBRIS CLOUDS WILL
DRIFT OVER THIS MORNING...IT IS EXPECTED TO DO LITTLE TO LIMIT
AGGRESSIVE WARMING TODAY. UPSTREAM OBSERVED TEMPERATURES YESTERDAY
AND CLIMATOLOGY FOR 850MB TEMPERATURES OF 14-16C IN LATE MAY
SUPPORT MID 80S FOR HIGHS. DEW POINTS...WHICH ARE THE KEY FACTOR
TO TODAYS AMOUNT OF INSTABILITY AND TIMING OF CAP BREAKING...ARE
FAVORED TO BE IN THE LOWER TO POOLED MID 60S ALONG THE FRONT.
THIS IS SUPPORTED BY UPSTREAM OBSERVATIONS WITHIN THE WARM SECTOR.
CONVECTIVE TEMPERATURES THEREFORE LOOK TO BE IN THE LOWER 80S IN
THE NORTHERN FORECAST AREA. HAVE LEANED AWAY FROM THE SLIGHTLY
MORE ROBUST AND QUICKLY INITIATING PAST 12KM NAM RUNS...WHICH
SEEMED INFLUENCE BY TOO HIGH OF BOUNDARY LAYER DEW POINTS. HAVE
LEANED THE FORECAST MORE WITH THE EC/GFS AS WELL AS MULTIPLE
CONVECTIVE ALLOWING MODELS /INCLUDING THE NAMS 4 KM RUN/...WHICH
SUPPORT MAINLY A LATE AFTERNOON DEVELOPMENT AND COVERAGE
INCREASING RAPIDLY 7-10 PM ACROSS NORTHERN IL.
WITH THE SURFACE LOW MOVING VERY SLOWLY ALONG THE INTERNATIONAL
BORDER THIS AFTERNOON...THE BOUNDARY WILL EASE IN SPEED WITH
CONVERGENCE WEAKENING...THOUGH STILL ENOUGH IN THE BOUNDARY LAYER
FOR A FOCUS. THE SECOND KEY IMPETUS LOOKS TO BE A MID-LEVEL SPEED
MAX AROUND 60KT PROJECTED TO EVOLVE OVER THE BOUNDARY IN SOUTHERN
WI/FAR NORTHERN IL LATE THIS AFTERNOON AND INTO EVE. THIS WILL ACT
TO WEAKEN ANY REMAINING CAP...SO EVEN IF CONVECTIVE TEMPERATURES
ARE NOT REACHED DURING PEAK HITTING...THIS SHOULD BE ENOUGH FOR
STORM DEVELOPMENT...THOUGH COVERAGE MAY BE ONLY SCATTERED PRIOR
TO SUNSET. THESE INCREASING MID-LEVEL WINDS WILL ALSO SUPPORT
REGENERATING AS WELL AS SUSTAINED CONVECTIVE CLUSTERS TONIGHT THAT
ARE FAVORED TO EVOLVE EAST SOUTHEAST WITH THE PRIMARILY STEERING
FLOW. THE CHICAGO AREA LOOKS TO MOST LIKELY SEE STORMS IN THE
EVENING PERIOD. /7 PM-12 AM/
FORECAST VALUES WITHIN THE INSTABILITY/SHEAR SPECTRUM ARE CERTAINLY
ENOUGH TO SUPPORT SEVERE STORMS LATE THIS AFTERNOON AND INTO
TONIGHT. CONCEPTUALLY...BEING AT THE EDGE OF THE ELEVATED MIXED
LAYER...WHICH IS FORECAST TO HAVE LAPSE RATES OF 8.5-9 C/KM...THE
POTENTIAL FOR LARGE HAIL EXISTS. THE 00Z EC DOES SUPPORT 500-800
J/KG OF -10C TO -30C CAPE...WHICH ADDS A CONDITIONAL THREAT FOR
POSSIBLY GOLF BALL OR LARGER HAIL...PRIMARILY WITH ANY STORMS THIS
AFTERNOON THROUGH MID-EVE...AS THEY ARE MORE LIKELY TO BE
DISCRETE. THOUGH AGAIN...COVERAGE OF THIS MAY BE QUITE LIMITED.
THE PRECISE MODE OF CONVECTION AND HOW FAR SOUTH IT MOVES TONIGHT
REMAINS UNCERTAIN...BUT HAVE KEPT THE IDEA THAT MORE OF THE
PROBABLE WELL-ORGANIZED CLUSTERS CAPABLE OF HAIL/WIND WOULD BE
FAVORED NORTH OF INTERSTATE 80...WHERE DEEP LAYER SHEAR IS
STRONGER AND EAST-ORIENTED VECTORS SUPPORT SUSTAINED CONVECTION
QUICKLY MOVING MORE EAST THAN SOUTH.
DID ADD THE MENTION OF PATCHY FOG LATE TONIGHT...GIVEN LIGHT WINDS
ALONG THE BOUNDARY AND CONVECTIVELY COOLED AIR IN PLACES WITH
LINGERING HIGH DEW POINTS. ITS CONCEIVABLE DENSE FOG COULD OCCUR
AND POSSIBLY BE SEEN AFTER DAYBREAK WEDNESDAY.
WEDNESDAY...
SOME FESTERING SHOWERS/STORMS MAY EXIST AROUND OR SOUTH OF THE
INTERSTATE 80 CORRIDOR IN THE EARLY MORNING...BUT THE FOCUS FOR
CONVECTION WOULD LIKELY BE AS CONVERGENCE ALONG THE FRONT IN THE
AFTERNOON. AN EARLIER INITIATION SHOULD OCCUR WEDNESDAY AFTERNOON
ALONG THIS BOUNDARY WITH SLIGHTLY HIGHER DEW POINTS AND
STRENGTHENING CONVERGENCE. QUITE A BIT OF SPREAD ON WHERE EXACTLY
THAT BOUNDARY IS. CONVECTION TONIGHT WILL CERTAINLY HAVE AN IMPACT
ON THAT. THE SPC SLIGHT RISK FOR DAY 2 INCLUDES THE FAR SOUTHEAST
WHICH SEEMS REASONABLE AND HAVE MAINLY KEPT FORECAST ON TRACK WITH
THAT. TEMPERATURES AREA WIDE ON WEDNESDAY LOOK TO BE VERY
MILD...WITH MID 80S PLAUSIBLE IN MOST AREAS /EXCEPTION WOULD BE
NORTHWEST INDIANA WITH ONSHORE FLOW/.
THURSDAY AND BEYOND...
FEW CHANGES MADE TO THIS PORTION OF THE FORECAST WITH FOCUS ON THE
SHORT TERM. AS PREVIOUS SHIFT DID...CONTINUE TO LEAN TOWARD SLOWER
GUIDANCE IN EVOLUTION OF THE NEXT CHANCE OF RAIN...WHICH MAY BE
MEMORIAL DAY...ALTHOUGH THE STRENGTH OF THE RIDGING ON ALL
GUIDANCE IS PRETTY IMPRESSIVE. THIS LOOKS TO SUPPORT TEMPERATURES
IN THE 80S ON THE HOLIDAY THAT OFFICIALLY KICKS OFF A LONG-AWAITED
SUMMER.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* TSRA POTENTIAL EARLY THIS EVENING.
* POTENTIAL FOR MVFR VSBY AND CIGS LATE TONIGHT INTO EARLY
WEDNESDAY.
* SWLY WINDS GUSTING TO 20 KT THROUGH THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
PRIMARY CONCERN FOR THE PERIOD WILL BE NARROWING DOWN THE TIMING
OF THE MOST LIKELY THUNDERSTORM POTENTIAL AND THEN FOLLOWED BY A
PERIOD OF LINGERING SHOWERS WITH SOME MVFR POTENTIAL FOR THE EARLY
MORNING HOURS.
FOR THE REMAINDER OF THE AFTERNOON...CONDITIONS SHOULD BE
UNRESTRICTED WITH SWLY WINDS OCNLY GUSTING IN THE UPPER TEENS.
DAYTIME MIXING WILL LARGELY DRIVE THE TIMING OF GENERAL
GUSTINESS...SO EXPECT THE GUSTS TO SETTLE AT SUNSET...OUTSIDE OF
THUNDERSTORMS.
AS FOR THE THUNDERSTORMS FORECAST...THE LATEST HIGH RES GUIDANCE
CONTINUES TO INDICATE THE BEST THUNDERSTORM POTENTIAL TO INITIAL
IN SRN WISCONSIN LATE THIS AFTERNOON AND THEN SLOWLY SAG SWD INTO
NRN IL DURG THE EARLY EVENING HOURS. GIVEN THE UNCERTAINTY IN
TIMING STILL AT THIS POINT...HAVE MAINTAINED THE GOING TIMING IN
THE TEMPO GROUP...BUT FEEL THAT LATER UPDATES WILL TRY TO NARROW
DOWN A PERIOD OF PREVAILING TS...BUT THAT WILL BE HIGHLY DEPENDENT
ON THE SPEED WITH WHICH THE FRONT SAGS SOUTH. THE OTHER CAVEAT FOR
THE THUNDER TIMING AT THE TERMINALS WILL BE THE SEVERE POTENTIAL
AND THE CONVECTIVE MODE OF SEVERE TS. IF THE CONVECTIVE MODE IS
STILL DISCRETE CELLS AT THE TIME TS IS INVOF THE TERMINALS...THEN
A PREVAILING TIMING WILL BE DIFFICULT TO DETERMINE. IF CONVECTIVE
MODE TRANSITIONS TO LINEAR...THEN A PREVAILING TIMING WILL BE MORE
CERTAIN.
FOLLOWING THE PASSAGE OF THE MAIN CONVECTIVE ACTIVITY...THERE
SHOULD BE A PERIOD OF TRAILING SHOWERS...AND WITH AMPLE MOISTURE
IN PLACE...MVFR CONDITIONS ARE LIKELY THROUGH AT LEAST DAYBREAK.
DAYTIME WARMING SHOULD HELP BREAK UP THE CLOUD COVER...AND THEN ANY
BR SHOULD IMPROVE BY LATE MORNING. THE REMAINDER OF WEDNESDAY
SHOULD BE QUIET...WITH VFR CONDITIONS AND WX/NIL.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH CONFIDENCE IN TSRA DIRECTLY IMPACTING TERMINALS THIS
EVENING...LOW CONFIDENCE IN EXACT TIMING AND DURATION OF DIRECT
IMPACTS TO TERMINALS.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS UNTIL LIKELY IMPACTS FROM
TSRA THIS EVENING.
* LOW-MEDIUM CONFIDENCE IN REDUCED VSBY/CIG POTENTIAL LATE
TONIGHT INTO EARLY WEDNESDAY.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY AND FRIDAY...VFR WITH LAKE BREEZE WIND SHIFT LIKELY.
SATURDAY...VFR WITH EAST-NORTHEAST WINDS.
SUNDAY...VFR. SOUTH-SOUTHEAST WINDS POSSIBLY BACKING EAST-SOUTHEAST.
MONDAY...VFR THEN CHANCE AFTERNOON TSRA.
RC
&&
.MARINE...
323 AM CDT
A DECENT PRESSURE GRADIENT IS IN PLACE EARLY THIS MORNING SUPPORTING
MODERATE SOUTHEASTERLY FLOW WITH GUSTS UP TO 25 KT. HOWEVER A LOW
PRESSURE TROUGH WILL ENVELOP THE LAKE BY THIS AFTERNOON AND CAUSE
SOUTHERLY WINDS TO WEAKEN. A WEAK COLD FRONT WILL DROP SOUTH
ACROSS THE LAKE TONIGHT INTO EARLY WEDNESDAY. WINDS WILL FURTHER
DIMINISH THIS EVENING...BUT A FEW THUNDERSTORMS COULD PRODUCE
GUSTY VARIABLE WINDS...HAIL AND FREQUENT LIGHTNING OVER THE
SOUTHERN THIRD OF THE LAKE. IN THE WAKE OF THE COLD FRONT...THERE
WILL BE FAIRLY LIGHT WEST TO NORTHWEST WINDS ON WEDNESDAY. HIGH
PRESSURE WILL BUILD ACROSS THE LAKE THURSDAY INTO SATURDAY...SETTING
UP AN EXTENDED PERIOD OF LIGHTER WINDS...ESPECIALLY LATE FRIDAY
INTO SATURDAY. WINDS IN THE NEARSHORE AREAS WILL BE CONTROLLED BY
LAKE BREEZE INFLUENCES THURSDAY THROUGH SATURDAY. SOUTHERLY WINDS
LOOK TO RETURN SUNDAY INTO MONDAY AS THE EXPANSIVE HIGH PRESSURE
AREA FINALLY SLIDES EAST.
WILL BE CANCELLING THE EXISTING SMALL CRAFT ADVISORY FOR THE
NEARSHORE WATERS EARLY AS SOUTHERLY WINDS HAVE DIMINISHED BELOW
CRITERIA AND VEERING OF WINDS WILL ENABLE WAVES TO QUICKLY SUBSIDE
ALONG FAR NORTHEAST ILLINOIS SHORE.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
647 PM EDT TUE MAY 20 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 344 PM EDT TUE MAY 20 2014
A FRONTAL SYSTEM WILL BRING CHANCES FOR THUNDERSTORMS TO CENTRAL
INDIANA STARTING LATE TONIGHT ACROSS THE NORTH AND SPREADING SOUTH
WEDNESDAY AS A COLD FRONT SINKS SOUTH THROUGH THE AREA. THE BEST
CHANCES FOR SEVERE STORMS WITH THIS SYSTEM WILL BE WEDNESDAY
AFTERNOON AND EVENING. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
THURSDAY USHERING IN DRY WEATHER WITH IT FOR THE REMAINDER OF THE
PERIOD.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 344 PM EDT TUE MAY 20 2014
SOME UNCERTAINTY STILL EXISTS WITH TONIGHT/S FORECAST CONCERNING HOW
FAR SOUTH STORMS WILL GET. SHORT TERM MODEL GUIDANCE WAS TRENDING
DRIER AND PUSHING THE POPS NORTH FOR SEVERAL RUNS THIS MORNING...BUT
LATEST RUNS OF RAP HAVE STARTED BRINGING ECHOES FURTHER SOUTH AND
VERY CLOSE TO THE NORTHERN COUNTIES. THE INFLUENCE OF THE UPPER RIDGE SHOULD
KEEP INITIAL FORMATION WELL NORTH OF THE FORECAST AREA AND EXPECT
CONDITIONS TO REMAIN DRY FOR A TIME AFTER 0Z. BY 6Z HOWEVER COULD
SEE STORMS STARTING TO APPROACH THE NORTHERN COUNTIES...AND WOULD
NOT BE OUT OF THE REALM OF POSSIBILITIES TO SEE AN MCS DEVELOP AND
RIDGE THE THETA E GRADIENT AROUND THE EDGE OF THE UPPER RIDGE WHICH
COULD BRING IT INTO THE NORTHERN/NORTHEASTERN COUNTIES. NAM SEEMS TO
FAVOR DEVELOPMENT A DECENT BIT FURTHER SOUTH THAN OTHER SOLUTIONS
AND GENERALLY DISCOUNTED IT. CONSIDERING THE UNCERTAINTY AND VARIETY
OF SOLUTIONS RIGHT NOW...THINK BEST COURSE OF ACTION IS TO INCLUDE
MID CHANCE POPS ALONG THE NORTHERN TO NORTHEASTERN BORDER AND BRING
A SLIGHT CHANCE DOWN ALONG THE EASTERN BORDER AROUND 9Z THAT RUNS
THROUGH 12Z TO ACCOUNT FOR THE LOW CHANCE OF A RIGHT TURNING MCS
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 344 PM EDT TUE MAY 20 2014
FORECAST FOCUS IS ON CHANCES FOR SEVERE STORMS WEDNESDAY. CIN DROPS
OFF DURING THE DAY ON WEDNESDAY WHILE MLCAPES CLIMB TO OVER 2000
OVER MUCH OF THE FORECAST AREA BY THE AFTERNOON. THE COLD FRONT
SHOULD GET INTO THE NORTHWESTERN COUNTIES AROUND 12-15Z AND START
SINKING SOUTH THROUGH THE AREA...BUT MOVES THROUGH VERY SLOWLY.
0-6 KM BULK SHEAR INCREASES DURING THE AFTERNOON AND...ALONG WITH
THE AFOREMENTIONED INSTABILITY AND FRONTAL FORCING...SHOULD BE
SUFFICIENT TO SUPPORT AN ORGANIZED SEVERE THREAT THAT WILL BE
MAXIMIZED DURING THE 18Z WED-3Z THU TIMEFRAME.
WITH THIS SET OF MODEL RUNS THE FRONT DOES NOT MOVE AS QUICKLY AWAY
FROM THE AREA AND THUS HELD POPS INTO EARLY THURSDAY MORNING
/STILL PRIOR TO 12Z/ IN THE SOUTH. LOOKS LIKE HIGH PRESSURE WILL
BE BUILDING IN ENOUGH TO DRY OUT ALL PRECIP BY 12Z THOUGH AND THEN
WILL KEEP THE WEATHER DRY THROUGH THE SHORT TERM.
FOR TEMPERATURES GUIDANCE WAS CLOSE AND GENERALLY USED A CONSENSUS
EXCEPT FOR WEDNESDAY WHEN FAVORED WARMER MAV NUMBERS BASED ON
CONTINUED STRONG WARM ADVECTION AHEAD OF THE COLD FRONT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 237 PM EDT TUE MAY 20 2014
HOLIDAY WEEKEND LOOKS FANTASTIC WITH WARM DRY WEATHER EXPECTED AS
SURFACE HIGH PRESSURE DRIFTS SLOWLY THROUGH THE OHIO VALLEY.
NORTHERLY FLOW AND WEAK COLD ADVECTION INITIALLY EXPECTED BUT AS
THE CENTER OF THE HIGH SHIFTS EAST OF THE REGION...RETURN FLOW AND
THE ARRIVAL OF AN UPPER RIDGE WILL ENABLE STEADILY WARMING TEMPS
WITH THE POTENTIAL FOR SOME OF THE WARMEST AIR OF THE YEAR SO FAR
TO ARRIVE MONDAY AND TUESDAY. HIGHS IN THE 70S SATURDAY WILL RISE
INTO THE MID 80S BY MONDAY AND TUESDAY WITH SOME HINTS THAT TEMPS
COULD FLIRT WITH THE UPPER 80S IN SOUTHERN COUNTIES.
INCREASING MOISTURE BY MONDAY AND TUESDAY COULD SUPPORT AN
ISOLATED CONVECTIVE THREAT BUT IN THE ABSENCE OF ANY SIGNIFICANT
FORCING UNDER THE RIDGE...BELIEVE CHANCES ARE TOO LOW TO MENTION
AT THIS TIME.
&&
.AVIATION /DISCUSSION FOR THE 210000Z KIND TAF ISSUANCE/...
ISSUED AT 641 PM EDT TUE MAY 20 2014
GENERALLY LOOKS LIKE VFR CONDITIONS FOR THIS PERIOD...WITH THE
POTENTIAL FOR SOME LOWER FLIGHT CATEGORIES (MFVR) ACROSS THE NRN
SITES SUCH AS KLAF AND KIND...CLOSER TO CONVECTIVE POTENTIAL LATE
TONIGHT INTO EARLY WED.
BASED ON LATEST RADAR MOSAIC AND SHORT RANGE MODEL
GUIDANCE...HAVE BACKED OFF ON MENTIONING ANY VCTS AND CB...SAVE FOR
KIND AND KLAF. KHUF AND KBMG LIKELY TO BE FAR ENOUGH SOUTH (AND
WEST) TO LIMIT ANY IMPACTS FROM A WEAKENING THUNDERSTORM CLUSTER.
MVFR AND LOWER RESTRICTIONS WILL BE POSSIBLE WITHIN THE STORMS
LATE TONIGHT AND WEDNESDAY MORNING.
MODEL SOUNDINGS SUPPORT SOME CLEARING BY MIDDAY WEDNESDAY WITH
WINDS VEERING TO A MORE WESTERLY DIRECTION AS THE COLD FRONT
SETTLES ACROSS CENTRAL INDIANA. RENEWED CONVECTIVE DEVELOPMENT
WEDNESDAY AFTERNOON EXPECTED AFTER 18Z FOCUSED ALONG AND SOUTH OF
I-70. CONFIDENCE IS LOW THIS FAR OUT IN THE FORECAST TO INCLUDE
ANY MENTION OF SHRA OR TS AT THIS TIME. ONLY INDICATED A LOW
STRATUS DECK AROUND 4K FT FOR THE TIME BEING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...SMF
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
408 PM EDT TUE MAY 20 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 344 PM EDT TUE MAY 20 2014
A FRONTAL SYSTEM WILL BRING CHANCES FOR THUNDERSTORMS TO CENTRAL
INDIANA STARTING LATE TONIGHT ACROSS THE NORTH AND SPREADING SOUTH
WEDNESDAY AS A COLD FRONT SINKS SOUTH THROUGH THE AREA. THE BEST
CHANCES FOR SEVERE STORMS WITH THIS SYSTEM WILL BE WEDNESDAY
AFTERNOON AND EVENING. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
THURSDAY USHERING IN DRY WEATHER WITH IT FOR THE REMAINDER OF THE
PERIOD.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 344 PM EDT TUE MAY 20 2014
SOME UNCERTAINTY STILL EXISTS WITH TONIGHT/S FORECAST CONCERNING HOW
FAR SOUTH STORMS WILL GET. SHORT TERM MODEL GUIDANCE WAS TRENDING
DRIER AND PUSHING THE POPS NORTH FOR SEVERAL RUNS THIS MORNING...BUT
LATEST RUNS OF RAP HAVE STARTED BRINGING ECHOES FURTHER SOUTH AND
VERY CLOSE TO THE NORTHERN COUNTIES. THE INFLUENCE OF THE UPPER RIDGE SHOULD
KEEP INITIAL FORMATION WELL NORTH OF THE FORECAST AREA AND EXPECT
CONDITIONS TO REMAIN DRY FOR A TIME AFTER 0Z. BY 6Z HOWEVER COULD
SEE STORMS STARTING TO APPROACH THE NORTHERN COUNTIES...AND WOULD
NOT BE OUT OF THE REALM OF POSSIBILITIES TO SEE AN MCS DEVELOP AND
RIDGE THE THETA E GRADIENT AROUND THE EDGE OF THE UPPER RIDGE WHICH
COULD BRING IT INTO THE NORTHERN/NORTHEASTERN COUNTIES. NAM SEEMS TO
FAVOR DEVELOPMENT A DECENT BIT FURTHER SOUTH THAN OTHER SOLUTIONS
AND GENERALLY DISCOUNTED IT. CONSIDERING THE UNCERTAINTY AND VARIETY
OF SOLUTIONS RIGHT NOW...THINK BEST COURSE OF ACTION IS TO INCLUDE
MID CHANCE POPS ALONG THE NORTHERN TO NORTHEASTERN BORDER AND BRING
A SLIGHT CHANCE DOWN ALONG THE EASTERN BORDER AROUND 9Z THAT RUNS
THROUGH 12Z TO ACCOUNT FOR THE LOW CHANCE OF A RIGHT TURNING MCS
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 344 PM EDT TUE MAY 20 2014
FORECAST FOCUS IS ON CHANCES FOR SEVERE STORMS WEDNESDAY. CIN DROPS
OFF DURING THE DAY ON WEDNESDAY WHILE MLCAPES CLIMB TO OVER 2000
OVER MUCH OF THE FORECAST AREA BY THE AFTERNOON. THE COLD FRONT
SHOULD GET INTO THE NORTHWESTERN COUNTIES AROUND 12-15Z AND START
SINKING SOUTH THROUGH THE AREA...BUT MOVES THROUGH VERY SLOWLY.
0-6 KM BULK SHEAR INCREASES DURING THE AFTERNOON AND...ALONG WITH
THE AFOREMENTIONED INSTABILITY AND FRONTAL FORCING...SHOULD BE
SUFFICIENT TO SUPPORT AN ORGANIZED SEVERE THREAT THAT WILL BE
MAXIMIZED DURING THE 18Z WED-3Z THU TIMEFRAME.
WITH THIS SET OF MODEL RUNS THE FRONT DOES NOT MOVE AS QUICKLY AWAY
FROM THE AREA AND THUS HELD POPS INTO EARLY THURSDAY MORNING
/STILL PRIOR TO 12Z/ IN THE SOUTH. LOOKS LIKE HIGH PRESSURE WILL
BE BUILDING IN ENOUGH TO DRY OUT ALL PRECIP BY 12Z THOUGH AND THEN
WILL KEEP THE WEATHER DRY THROUGH THE SHORT TERM.
FOR TEMPERATURES GUIDANCE WAS CLOSE AND GENERALLY USED A CONSENSUS
EXCEPT FOR WEDNESDAY WHEN FAVORED WARMER MAV NUMBERS BASED ON
CONTINUED STRONG WARM ADVECTION AHEAD OF THE COLD FRONT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 237 PM EDT TUE MAY 20 2014
HOLIDAY WEEKEND LOOKS FANTASTIC WITH WARM DRY WEATHER EXPECTED AS
SURFACE HIGH PRESSURE DRIFTS SLOWLY THROUGH THE OHIO VALLEY.
NORTHERLY FLOW AND WEAK COLD ADVECTION INITIALLY EXPECTED BUT AS
THE CENTER OF THE HIGH SHIFTS EAST OF THE REGION...RETURN FLOW AND
THE ARRIVAL OF AN UPPER RIDGE WILL ENABLE STEADILY WARMING TEMPS
WITH THE POTENTIAL FOR SOME OF THE WARMEST AIR OF THE YEAR SO FAR
TO ARRIVE MONDAY AND TUESDAY. HIGHS IN THE 70S SATURDAY WILL RISE
INTO THE MID 80S BY MONDAY AND TUESDAY WITH SOME HINTS THAT TEMPS
COULD FLIRT WITH THE UPPER 80S IN SOUTHERN COUNTIES.
INCREASING MOISTURE BY MONDAY AND TUESDAY COULD SUPPORT AN
ISOLATED CONVECTIVE THREAT BUT IN THE ABSENCE OF ANY SIGNIFICANT
FORCING UNDER THE RIDGE...BELIEVE CHANCES ARE TOO LOW TO MENTION
AT THIS TIME.
&&
.AVIATION /DISCUSSION FOR THE 202100Z KIND TAF UPDATE/...
ISSUED AT 408 PM EDT TUE MAY 20 2014
NO SIGNIFICANT CHANGES MADE AT THIS TIME. PREVIOUS DISCUSSION
FOLLOWS.
MAINLY VFR CONDITIONS THROUGHOUT THE PERIOD. POTENTIAL FOR
RESTRICTIONS WITHIN CONVECTION LATE TONIGHT AND EARLY WEDNESDAY.
EARLIER MID AND HIGH CLOUDS HAVE LARGELY SHIFTED EAST OF THE
TERMINALS EARLY THIS AFTERNOON. AS TEMPS HAVE SOARED INTO THE
70S...ALREADY SEEING CU DEVELOPMENT AND EXPECT IT TO EXPAND IN
COVERAGE THROUGH THE REMAINDER OF THE AFTERNOON. SOUTHWEST WIND
GUSTS UP TO 25KTS WILL BE POSSIBLE THROUGH EARLY THIS EVENING.
MAIN FOCUS OF THE FORECAST WILL BE CONVECTIVE POTENTIAL AND
POSSIBLE IMPACT TO TERMINAL OPS LATE TONIGHT INTO EARLY WEDNESDAY.
SHORT RANGE MODEL GUIDANCE SUPPORTING CONVECTIVE DEVELOPMENT
NORTHWEST OF THE REGION IN THE VICINITY OF THE COLD FRONT. WITH
THE EXCEPTION OF THE NAM...ALL MODEL DATA KEEPING CONVECTION
CONFINED NORTH OF THE REGION THROUGH 06Z...WITH SOUTHWARD
EXPANSION THEREAFTER AS THE STORMS COALESCE INTO A CONVECTIVE
COMPLEX. HAVE BACKED OFF VCTS ARRIVAL AT KHUF/KIND/KLAF BY SEVERAL
HOURS FROM PREVIOUS FORECAST. KBMG LIKELY TO BE FAR ENOUGH SOUTH
TO LIMIT ANY IMPACTS FROM A WEAKENING THUNDERSTORM CLUSTER. MVFR
AND LOWER RESTRICTIONS WILL BE POSSIBLE WITHIN THE STORMS LATE
TONIGHT AND WEDNESDAY MORNING.
MODEL SOUNDINGS SUPPORT SOME CLEARING BY MIDDAY WEDNESDAY WITH
WINDS VEERING TO A MORE WESTERLY DIRECTION AS THE COLD FRONT
SETTLES ACROSS CENTRAL INDIANA. RENEWED CONVECTIVE DEVELOPMENT
WEDNESDAY AFTERNOON EXPECTED AFTER 18Z FOCUSED ALONG AND SOUTH OF
I-70.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...RYAN/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
350 PM EDT TUE MAY 20 2014
.SYNOPSIS...
ISSUED AT 343 PM EDT TUE MAY 20 2014
A COLD FRONT WILL SLOWLY SLIP SOUTH INTO THE REGION OVER THE NEXT
24 HOURS. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TONIGHT...ESPECIALLY ACROSS PORTIONS OF LOWER MICHIGAN...NORTHERN
INDIANA AND NORTHWESTERN OHIO WITH SEVERE WEATHER A POSSIBILITY.
THE COLD FRONT WILL MOVE THROUGH ON WEDNESDAY WITH ADDITIONAL
CHANCES OF SHOWERS AND THUNDERSTORMS. LOWS TONIGHT WILL DROP INTO
THE 60S WITH HIGHS WEDNESDAY GENERALLY IN THE LOWER 80S...WITH
LOCALLY COOLER CONDITIONS ALONG THE LAKE.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 333 PM EDT TUE MAY 20 2014
...THREAT OF SEVERE WEATHER THIS EVENING...POSSIBLY INTO OVERNIGHT
HOURS...
MAIN FOCUS RESIDES ON COLD FRONT EXTENDING FROM CNTRL LK MI INTO
IOWA WHICH WILL BECOME THE TRIGGER POINT FOR THUNDERSTORMS OVER THE
NEXT COUPLE OF HOURS. CONCERNS LOOM IN EXACTLY HOW THESE STORMS WILL
EVOLVE AND DROP SE TOWARDS THE FORECAST AREA TONIGHT. SPC
MESOANALYSIS SHOWS SFC BASED CAPES 2000 TO 3000 J/KG WERE POOLING
ALONG THE FRONT WITH STEEPENING LAPSE RATES AND INCREASING SHEAR. CU
FIELD HAVE BEEN RATHER SUBDUED THUS FAR ALONG THE FRONT. HOWEVER ALL
HIGH RES MODELS SEEM TO POINT TOWARDS RAPID FORMATION OF STORMS IN
THE 21 TO 23Z TIME FRAME. INITIAL STORM MODE SHOULD BE MULTICELL
CLUSTERS/SOME SUPERCELLS WHICH WILL PRODUCE HAIL AND DAMAGING
WINDS...ALONG WITH SOME TORNADO THREAT. COLD POOL SHOULD BEGIN TO
ESTABLISH WITH CORFIDI VECTORS INDICATED A RAPID FORWARD PROPAGATION
INTO NW PARTS OF THE AREA AFTER 00Z AND OVERSPREADING AT LEAST
NORTHERN HALF THE REMAINDER OF THE EVENING. TIMING OF DAY WILL PLAY
SOMEWHAT AGAINST SEVERE POTENTIAL AS WILL FACT THAT ACTUAL COLD
FRONT WILL RESIDE WELL NW OF THE AREA UNTIL LATER TONIGHT.
HOWEVER...ALL SIGNS CONTINUE TO POINT TOWARDS INCREASING SEVERE
THREAT THIS EVENING...WARRANTING INCREASE IN POPS AND ADDITION OF
SVR WORDING. SOUTHERN EXTENT VERY QUESTIONABLE AS OUTFLOW BOUNDARIES
EVENTUALLY RACE AHEAD OF THE LINE AND ALLOW FOR POTENTIAL FOR THE
LINE TO STALL OUT WITH HRRR INDICATING SOME POTENTIAL FOR ADDITIONAL
DEVELOPMENT ACROSS ILLINOIS/IOWA MOVING IN LATER THIS EVENING. HAVE
NOT ADDED MENTION OF HVY RAIN...BUT TRAINING OF CELLS WILL BE
POSSIBLE WITH INHERENT THREAT FOR FLOODING. WILL DEFER TO EVE SHIFT
TO MONITOR TRENDS.
NO CHANGES TO FORECAST ON WEDNESDAY WITH RESIDUAL BOUNDARY FROM
OVERNIGHT CONVECTION BEING KEY IN CONVECTIVE CHANCES AS ACTUAL COLD
FRONT MOVES IN. NEW DAY2 OUTLOOK HAS SHOVED SLGT RISK A BIT FURTHER
SOUTH ACROSS MAINLY SE THIRD OF THE AREA WHICH IS REASONABLE AT THIS
STAGE. WILL DEFER TO OVERNIGHT SHIFT TO MAKE ADJUSTMENTS.
&&
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 333 PM EDT TUE MAY 20 2014
CDFNT SHOULD BE MOVG THROUGH S-SE PORTION OF CWA AT START OF THE
PERIOD WED EVE. CONVECTION WILL PRBLY HAVE MOVED OUT AHEAD OF THE
FRONT BY 00Z AND BE LOCATED S-SE OF THE CWA, BUT THERE IS A SMALL
CHC OF ACTIVITY CONTG TO DEVELOP ALONG IT, SO MAINTAINED A LOW POP
THROUGH WED EVE. COOLER/DRIER AIRMASS WILL SPREAD INTO THE AREA
BEHIND THE CDFNT BY THURSDAY. SHRTWV MOVG THROUGH THE UPR GRTLKS
TONIGHT/WED EXPECTED TO TRANSITION TO A CUT-OFF LOW OVER NERN
U.S./SE CANADA BY THU WITH ANOTHER CUT-OFF LOW LINGERING OVER THE
SWRN CONUS WHILE IN BETWEEEN RIDGE OVER CENTRAL U.S. WILL PROVIDE
OUR AREA WITH FAIR WX LATE THIS WEEK. THESE SYSTEMS EXPECTED TO MAKE
SLOW E-NE PROGRESS OVER THE WEEKEND AND EARLY NEXT WEEK, LIKELY
CONTG THE DRY SPELL ACROSS OUR CWA. TEMPS THU SHOULD BE A BIT BLO
NORMAL, MODIFYING TO WELL ABOVE NORMAL OVER THE HOLIDAY WEEKEND AS
THE UPR RIDGE BUILDS INTO THE AREA. RETURN FLOW WILL RESULT IN
INCREASING LOW LEVEL MOISTURE AND SOME DEVELOPING INSTABILITY AS SFC
HIGH MOVES EAST OF THE AREA BY MONDAY, BUT PROXIMITY OF UPR LEVEL
RIDGE SUGGESTS ANY CONVECTION IN OUR AREA WILL BE ISOLATED AT BEST,
SO FOR NOW HELD OFF ADDING TO FCST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1250 PM EDT TUE MAY 20 2014
VFR TAFS INTO EARLY EVENING AS INCREASING CAPPING CONTINUES ACROSS
THE AREA...KEEPING CONVECTION SUPPRESSED FOR THE TIME BEING.
CONVECTION WILL LIKELY FIRE TO THE WEST OF THE AREA ACROSS
ILLINOIS AND BEGIN TO EDGE INTO KSBN AFTER 00Z AND LIKELY INTO
KFWA SEVERAL HOURS LATER. SOME CONCERN THAT PRECIP COULD TAKE A
WHILE TO REACH KFWA (AFTER 6Z) BUT WILL STICK WITH PREV THOUGHTS
AND CONVERT PROB30 TO TEMPO GROUP AND ADJUST TIMING SOMEWHAT FOR A
SLIGHTLY LATER ARRIVAL. GUIDANCE BRINGS IN MUCH LOWER CIGS LATER
TONIGHT INTO WEDS BUT REMAINING CONSERVATIVE PENDING
FORMATION/EVOLUTION OF OVERNIGHT PRECIP.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MURPHY/FISHER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...FISHER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
348 PM EDT TUE MAY 20 2014
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 344 PM EDT TUE MAY 20 2014
A FRONTAL SYSTEM WILL BRING CHANCES FOR THUNDERSTORMS TO CENTRAL
INDIANA STARTING LATE TONIGHT ACROSS THE NORTH AND SPREADING SOUTH
WEDNESDAY AS A COLD FRONT SINKS SOUTH THROUGH THE AREA. THE BEST
CHANCES FOR SEVERE STORMS WITH THIS SYSTEM WILL BE WEDNESDAY
AFTERNOON AND EVENING. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
THURSDAY USHERING IN DRY WEATHER WITH IT FOR THE REMAINDER OF THE
PERIOD.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 344 PM EDT TUE MAY 20 2014
SOME UNCERTAINTY STILL EXISTS WITH TONIGHT/S FORECAST CONCERNING HOW
FAR SOUTH STORMS WILL GET. SHORT TERM MODEL GUIDANCE WAS TRENDING
DRIER AND PUSHING THE POPS NORTH FOR SEVERAL RUNS THIS MORNING...BUT
LATEST RUNS OF RAP HAVE STARTED BRINGING ECHOES FURTHER SOUTH AND
VERY CLOSE TO THE NORTHERN COUNTIES. THE INFLUENCE OF THE UPPER RIDGE SHOULD
KEEP INITIAL FORMATION WELL NORTH OF THE FORECAST AREA AND EXPECT
CONDITIONS TO REMAIN DRY FOR A TIME AFTER 0Z. BY 6Z HOWEVER COULD
SEE STORMS STARTING TO APPROACH THE NORTHERN COUNTIES...AND WOULD
NOT BE OUT OF THE REALM OF POSSIBILITIES TO SEE AN MCS DEVELOP AND
RIDGE THE THETA E GRADIENT AROUND THE EDGE OF THE UPPER RIDGE WHICH
COULD BRING IT INTO THE NORTHERN/NORTHEASTERN COUNTIES. NAM SEEMS TO
FAVOR DEVELOPMENT A DECENT BIT FURTHER SOUTH THAN OTHER SOLUTIONS
AND GENERALLY DISCOUNTED IT. CONSIDERING THE UNCERTAINTY AND VARIETY
OF SOLUTIONS RIGHT NOW...THINK BEST COURSE OF ACTION IS TO INCLUDE
MID CHANCE POPS ALONG THE NORTHERN TO NORTHEASTERN BORDER AND BRING
A SLIGHT CHANCE DOWN ALONG THE EASTERN BORDER AROUND 9Z THAT RUNS
THROUGH 12Z TO ACCOUNT FOR THE LOW CHANCE OF A RIGHT TURNING MCS
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 344 PM EDT TUE MAY 20 2014
FORECAST FOCUS IS ON CHANCES FOR SEVERE STORMS WEDNESDAY. CIN DROPS
OFF DURING THE DAY ON WEDNESDAY WHILE MLCAPES CLIMB TO OVER 2000
OVER MUCH OF THE FORECAST AREA BY THE AFTERNOON. THE COLD FRONT
SHOULD GET INTO THE NORTHWESTERN COUNTIES AROUND 12-15Z AND START
SINKING SOUTH THROUGH THE AREA...BUT MOVES THROUGH VERY SLOWLY.
0-6 KM BULK SHEAR INCREASES DURING THE AFTERNOON AND...ALONG WITH
THE AFOREMENTIONED INSTABILITY AND FRONTAL FORCING...SHOULD BE
SUFFICIENT TO SUPPORT AN ORGANIZED SEVERE THREAT THAT WILL BE
MAXIMIZED DURING THE 18Z WED-3Z THU TIMEFRAME.
WITH THIS SET OF MODEL RUNS THE FRONT DOES NOT MOVE AS QUICKLY AWAY
FROM THE AREA AND THUS HELD POPS INTO EARLY THURSDAY MORNING
/STILL PRIOR TO 12Z/ IN THE SOUTH. LOOKS LIKE HIGH PRESSURE WILL
BE BUILDING IN ENOUGH TO DRY OUT ALL PRECIP BY 12Z THOUGH AND THEN
WILL KEEP THE WEATHER DRY THROUGH THE SHORT TERM.
FOR TEMPERATURES GUIDANCE WAS CLOSE AND GENERALLY USED A CONSENSUS
EXCEPT FOR WEDNESDAY WHEN FAVORED WARMER MAV NUMBERS BASED ON
CONTINUED STRONG WARM ADVECTION AHEAD OF THE COLD FRONT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 237 PM EDT TUE MAY 20 2014
HOLIDAY WEEKEND LOOKS FANTASTIC WITH WARM DRY WEATHER EXPECTED AS
SURFACE HIGH PRESSURE DRIFTS SLOWLY THROUGH THE OHIO VALLEY.
NORTHERLY FLOW AND WEAK COLD ADVECTION INITIALLY EXPECTED BUT AS
THE CENTER OF THE HIGH SHIFTS EAST OF THE REGION...RETURN FLOW AND
THE ARRIVAL OF AN UPPER RIDGE WILL ENABLE STEADILY WARMING TEMPS
WITH THE POTENTIAL FOR SOME OF THE WARMEST AIR OF THE YEAR SO FAR
TO ARRIVE MONDAY AND TUESDAY. HIGHS IN THE 70S SATURDAY WILL RISE
INTO THE MID 80S BY MONDAY AND TUESDAY WITH SOME HINTS THAT TEMPS
COULD FLIRT WITH THE UPPER 80S IN SOUTHERN COUNTIES.
INCREASING MOISTURE BY MONDAY AND TUESDAY COULD SUPPORT AN
ISOLATED CONVECTIVE THREAT BUT IN THE ABSENCE OF ANY SIGNIFICANT
FORCING UNDER THE RIDGE...BELIEVE CHANCES ARE TOO LOW TO MENTION
AT THIS TIME.
&&
.AVIATION /DISCUSSION FOR 201800Z TAF ISSUANCE/...
ISSUED AT 114 PM EDT TUE MAY 20 2014
MAINLY VFR CONDITIONS THROUGHOUT THE PERIOD. POTENTIAL FOR
RESTRICTIONS WITHIN CONVECTION LATE TONIGHT AND EARLY WEDNESDAY.
EARLIER MID AND HIGH CLOUDS HAVE LARGELY SHIFTED EAST OF THE
TERMINALS EARLY THIS AFTERNOON. AS TEMPS HAVE SOARED INTO THE
70S...ALREADY SEEING CU DEVELOPMENT AND EXPECT IT TO EXPAND IN
COVERAGE THROUGH THE REMAINDER OF THE AFTERNOON. SOUTHWEST WIND
GUSTS UP TO 25KTS WILL BE POSSIBLE THROUGH EARLY THIS EVENING.
MAIN FOCUS OF THE FORECAST WILL BE CONVECTIVE POTENTIAL AND
POSSIBLE IMPACT TO TERMINAL OPS LATE TONIGHT INTO EARLY WEDNESDAY.
SHORT RANGE MODEL GUIDANCE SUPPORTING CONVECTIVE DEVELOPMENT
NORTHWEST OF THE REGION IN THE VICINITY OF THE COLD FRONT. WITH
THE EXCEPTION OF THE NAM...ALL MODEL DATA KEEPING CONVECTION
CONFINED NORTH OF THE REGION THROUGH 06Z...WITH SOUTHWARD
EXPANSION THEREAFTER AS THE STORMS COALESCE INTO A CONVECTIVE
COMPLEX. HAVE BACKED OFF VCTS ARRIVAL AT KHUF/KIND/KLAF BY SEVERAL
HOURS FROM PREVIOUS FORECAST. KBMG LIKELY TO BE FAR ENOUGH SOUTH
TO LIMIT ANY IMPACTS FROM A WEAKENING THUNDERSTORM CLUSTER. MVFR
AND LOWER RESTRICTIONS WILL BE POSSIBLE WITHIN THE STORMS LATE
TONIGHT AND WEDNESDAY MORNING.
MODEL SOUNDINGS SUPPORT SOME CLEARING BY MIDDAY WEDNESDAY WITH
WINDS VEERING TO A MORE WESTERLY DIRECTION AS THE COLD FRONT
SETTLES ACROSS CENTRAL INDIANA. RENEWED CONVECTIVE DEVELOPMENT
WEDNESDAY AFTERNOON EXPECTED AFTER 18Z FOCUSED ALONG AND SOUTH OF
I-70.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
237 PM EDT TUE MAY 20 2014
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 326 AM EDT TUE MAY 20 2014
A WARM FRONT WILL TRAVERSE CENTRAL INDIANA TODAY...BRINGING HIGH
TEMPS BACK INTO THE 80S. THERE IS A SLIGHT CHANCE FOR SOME
SCATTERED SHOWERS AND THUNDERSTORMS ALONG THAT FRONTAL BOUNDARY OVER
NORTHERN PORTIONS OF THE AREA TONIGHT...BUT THE BEST CHANCES FOR
CONVECTION WILL BE TOMORROW WHEN A COLD FRONT HITS THE DESTABILIZED
ENVIRONMENT. ALL OF CENTRAL INDIANA IS CURRENTLY UNDER A SLIGHT
RISK FOR SEVERE THUNDERSTORMS TOMORROW AS A RESULT. FURTHER
OUT...A DRY FORECAST IS NOW EXPECTED TO PREVAIL FROM THURSDAY
THROUGH THE EXTENDED PERIOD AFTER MUCH MODEL INCONSISTENCY OVER
LAST WEEKEND. THE LAST FEW RUNS HAVE NOW SETTLED ON A DRY PATTERN
THROUGH THE EXTENDED PERIOD.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1006 AM EDT TUE MAY 20 2014
FOR THE UPDATE...INCREASED CLOUD COVER BASED ON CURRENT SATELLITE
TRENDS AND ADDED ISOLATED SPRINKLES FOR THE NEXT COUPLE OF HOURS IN
THE EASTERN COUNTIES BASED ON RADAR RETURNS. CLOUDS SHOULD THIN OUT
TO PARTLY CLOUDY FOR THE AFTERNOON THOUGH AND STILL EXPECT
TEMPERATURES TO CLIMB TO THE LOW TO MID 80S WITH GUSTY SOUTHWEST
WINDS. LATEST HRRR AND RAP ARE KEEPING THUNDERSTORMS OUT OF THE
FORECAST AREA UNTIL WELL AFTER 0Z SO KEPT DRY POP GOING THROUGH THEN
WITH SEVERE RISK NOT IN PLAY UNTIL THE TONIGHT PERIOD AS WELL.
PREVIOUS DISCUSSION FOLLOWS...
THE MAIN FOCUS OF THE NEAR TERM PERIOD IS A WARM FRONT PROGGED TO
TRACK ACROSS CENTRAL INDIANA TODAY. STRONG SOUTHWEST FLOW/WARM AIR
ADVECTION WAS MAIN FACTOR IN TRENDING ABOVE GUIDANCE FOR TODAY/S
HIGHS. THE END RESULT WAS FORECASTED HIGHS IN THE LOW TO MID 80S.
IN REGARD TO PRECIP CHANCES FOR TODAY...THE NAM REMAINS THE
OUTLYING MODEL IN BRINGING CONVECTION INTO THE NORTHERN COUNTIES
LATE THIS MORNING/AFTERNOON. HOWEVER...RAPID REFRESH IS INDICATING
DRY CONDITIONS THROUGH THE AFTERNOON...AND THE GFS IS ALSO ON
BOARD WITH THAT. DECIDED TO HOLD OFF ON THUNDERSTORM CHANCES OVER
THE NORTHERN COUNTIES UNTIL THIS EVENING WHEN DYNAMICS IMPROVE
WITH APPROACHING COLD FRONT. SPC ALSO HAS A SLIGHT RISK IN PLACE
FOR THE NORTHERN HALF OF OUR FORECAST AREA FOR DAY 1...BUT MAINLY
FOCUSING DURING THAT EVENING TIME FRAME AS WELL.
CURRENTLY...TEMPS ACROSS THE AREA ARE GENERALLY IN THE LOW 60S
WITH SOUTHEASTERLY WINDS OF 5 TO 10 MPH.
&&
.SHORT TERM /T0NIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 326 AM EDT TUE MAY 20 2014
THE MAIN FOCUS OF THE SHORT TERM PERIOD IS SEVERE THUNDERSTORM
THREAT IN ASSOCIATION WITH COLD FRONT. SPC CONTINUES TO KEEP ALL
OF CENTRAL INDIANA UNDER A SLIGHT RISK FOR DAY 2.
COLD FRONT IS EXPECTED TO ENTER A RATHER DESTABILIZED ENVIRONMENT
TOMORROW AFTERNOON. MLCAPES REMAIN IMPRESSIVE WITH SUBSTANTIAL
DAYTIME HEATING. LOW LEVEL MOISTURE REMAINS A BIT OVERDONE...BUT
SHOULD STILL BE SUFFICIENT. WESTERLY FLOW WILL BE CONSISTENT
THROUGH ALL LEVELS. THERE WILL BE A LACK OF DIRECTIONAL
SHEAR...BUT SPEED SHEAR WILL BE FAIRLY STRONG.
ACTIVITY WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST ON WEDNESDAY
EVENING AND THE REMAINDER OF SHORT TERM PERIOD WILL BE DRY. HIGHS
WILL FALL BACK INTO THE 70S FOR THURSDAY IN WAKE OF COLD FRONT.
STUCK WITH A MODEL BLEND FOR TEMPS THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 237 PM EDT TUE MAY 20 2014
HOLIDAY WEEKEND LOOKS FANTASTIC WITH WARM DRY WEATHER EXPECTED AS
SURFACE HIGH PRESSURE DRIFTS SLOWLY THROUGH THE OHIO VALLEY.
NORTHERLY FLOW AND WEAK COLD ADVECTION INITIALLY EXPECTED BUT AS
THE CENTER OF THE HIGH SHIFTS EAST OF THE REGION...RETURN FLOW AND
THE ARRIVAL OF AN UPPER RIDGE WILL ENABLE STEADILY WARMING TEMPS
WITH THE POTENTIAL FOR SOME OF THE WARMEST AIR OF THE YEAR SO FAR
TO ARRIVE MONDAY AND TUESDAY. HIGHS IN THE 70S SATURDAY WILL RISE
INTO THE MID 80S BY MONDAY AND TUESDAY WITH SOME HINTS THAT TEMPS
COULD FLIRT WITH THE UPPER 80S IN SOUTHERN COUNTIES.
INCREASING MOISTURE BY MONDAY AND TUESDAY COULD SUPPORT AN
ISOLATED CONVECTIVE THREAT BUT IN THE ABSENCE OF ANY SIGNIFICANT
FORCING UNDER THE RIDGE...BELIEVE CHANCES ARE TOO LOW TO MENTION
AT THIS TIME.
&&
.AVIATION /DISCUSSION FOR 201800Z TAF ISSUANCE/...
ISSUED AT 114 PM EDT TUE MAY 20 2014
MAINLY VFR CONDITIONS THROUGHOUT THE PERIOD. POTENTIAL FOR
RESTRICTIONS WITHIN CONVECTION LATE TONIGHT AND EARLY WEDNESDAY.
EARLIER MID AND HIGH CLOUDS HAVE LARGELY SHIFTED EAST OF THE
TERMINALS EARLY THIS AFTERNOON. AS TEMPS HAVE SOARED INTO THE
70S...ALREADY SEEING CU DEVELOPMENT AND EXPECT IT TO EXPAND IN
COVERAGE THROUGH THE REMAINDER OF THE AFTERNOON. SOUTHWEST WIND
GUSTS UP TO 25KTS WILL BE POSSIBLE THROUGH EARLY THIS EVENING.
MAIN FOCUS OF THE FORECAST WILL BE CONVECTIVE POTENTIAL AND
POSSIBLE IMPACT TO TERMINAL OPS LATE TONIGHT INTO EARLY WEDNESDAY.
SHORT RANGE MODEL GUIDANCE SUPPORTING CONVECTIVE DEVELOPMENT
NORTHWEST OF THE REGION IN THE VICINITY OF THE COLD FRONT. WITH
THE EXCEPTION OF THE NAM...ALL MODEL DATA KEEPING CONVECTION
CONFINED NORTH OF THE REGION THROUGH 06Z...WITH SOUTHWARD
EXPANSION THEREAFTER AS THE STORMS COALESCE INTO A CONVECTIVE
COMPLEX. HAVE BACKED OFF VCTS ARRIVAL AT KHUF/KIND/KLAF BY SEVERAL
HOURS FROM PREVIOUS FORECAST. KBMG LIKELY TO BE FAR ENOUGH SOUTH
TO LIMIT ANY IMPACTS FROM A WEAKENING THUNDERSTORM CLUSTER. MVFR
AND LOWER RESTRICTIONS WILL BE POSSIBLE WITHIN THE STORMS LATE
TONIGHT AND WEDNESDAY MORNING.
MODEL SOUNDINGS SUPPORT SOME CLEARING BY MIDDAY WEDNESDAY WITH
WINDS VEERING TO A MORE WESTERLY DIRECTION AS THE COLD FRONT
SETTLES ACROSS CENTRAL INDIANA. RENEWED CONVECTIVE DEVELOPMENT
WEDNESDAY AFTERNOON EXPECTED AFTER 18Z FOCUSED ALONG AND SOUTH OF
I-70.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD/CP
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
114 PM EDT TUE MAY 20 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 326 AM EDT TUE MAY 20 2014
A WARM FRONT WILL TRAVERSE CENTRAL INDIANA TODAY...BRINGING HIGH
TEMPS BACK INTO THE 80S. THERE IS A SLIGHT CHANCE FOR SOME
SCATTERED SHOWERS AND THUNDERSTORMS ALONG THAT FRONTAL BOUNDARY OVER
NORTHERN PORTIONS OF THE AREA TONIGHT...BUT THE BEST CHANCES FOR
CONVECTION WILL BE TOMORROW WHEN A COLD FRONT HITS THE DESTABILIZED
ENVIRONMENT. ALL OF CENTRAL INDIANA IS CURRENTLY UNDER A SLIGHT
RISK FOR SEVERE THUNDERSTORMS TOMORROW AS A RESULT. FURTHER
OUT...A DRY FORECAST IS NOW EXPECTED TO PREVAIL FROM THURSDAY
THROUGH THE EXTENDED PERIOD AFTER MUCH MODEL INCONSISTENCY OVER
LAST WEEKEND. THE LAST FEW RUNS HAVE NOW SETTLED ON A DRY PATTERN
THROUGH THE EXTENDED PERIOD.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1006 AM EDT TUE MAY 20 2014
FOR THE UPDATE...INCREASED CLOUD COVER BASED ON CURRENT SATELLITE
TRENDS AND ADDED ISOLATED SPRINKLES FOR THE NEXT COUPLE OF HOURS IN
THE EASTERN COUNTIES BASED ON RADAR RETURNS. CLOUDS SHOULD THIN OUT
TO PARTLY CLOUDY FOR THE AFTERNOON THOUGH AND STILL EXPECT
TEMPERATURES TO CLIMB TO THE LOW TO MID 80S WITH GUSTY SOUTHWEST
WINDS. LATEST HRRR AND RAP ARE KEEPING THUNDERSTORMS OUT OF THE
FORECAST AREA UNTIL WELL AFTER 0Z SO KEPT DRY POP GOING THROUGH THEN
WITH SEVERE RISK NOT IN PLAY UNTIL THE TONIGHT PERIOD AS WELL.
PREVIOUS DISCUSSION FOLLOWS...
THE MAIN FOCUS OF THE NEAR TERM PERIOD IS A WARM FRONT PROGGED TO
TRACK ACROSS CENTRAL INDIANA TODAY. STRONG SOUTHWEST FLOW/WARM AIR
ADVECTION WAS MAIN FACTOR IN TRENDING ABOVE GUIDANCE FOR TODAY/S
HIGHS. THE END RESULT WAS FORECASTED HIGHS IN THE LOW TO MID 80S.
IN REGARD TO PRECIP CHANCES FOR TODAY...THE NAM REMAINS THE
OUTLYING MODEL IN BRINGING CONVECTION INTO THE NORTHERN COUNTIES
LATE THIS MORNING/AFTERNOON. HOWEVER...RAPID REFRESH IS INDICATING
DRY CONDITIONS THROUGH THE AFTERNOON...AND THE GFS IS ALSO ON
BOARD WITH THAT. DECIDED TO HOLD OFF ON THUNDERSTORM CHANCES OVER
THE NORTHERN COUNTIES UNTIL THIS EVENING WHEN DYNAMICS IMPROVE
WITH APPROACHING COLD FRONT. SPC ALSO HAS A SLIGHT RISK IN PLACE
FOR THE NORTHERN HALF OF OUR FORECAST AREA FOR DAY 1...BUT MAINLY
FOCUSING DURING THAT EVENING TIME FRAME AS WELL.
CURRENTLY...TEMPS ACROSS THE AREA ARE GENERALLY IN THE LOW 60S
WITH SOUTHEASTERLY WINDS OF 5 TO 10 MPH.
&&
.SHORT TERM /T0NIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 326 AM EDT TUE MAY 20 2014
THE MAIN FOCUS OF THE SHORT TERM PERIOD IS SEVERE THUNDERSTORM
THREAT IN ASSOCIATION WITH COLD FRONT. SPC CONTINUES TO KEEP ALL
OF CENTRAL INDIANA UNDER A SLIGHT RISK FOR DAY 2.
COLD FRONT IS EXPECTED TO ENTER A RATHER DESTABILIZED ENVIRONMENT
TOMORROW AFTERNOON. MLCAPES REMAIN IMPRESSIVE WITH SUBSTANTIAL
DAYTIME HEATING. LOW LEVEL MOISTURE REMAINS A BIT OVERDONE...BUT
SHOULD STILL BE SUFFICIENT. WESTERLY FLOW WILL BE CONSISTENT
THROUGH ALL LEVELS. THERE WILL BE A LACK OF DIRECTIONAL
SHEAR...BUT SPEED SHEAR WILL BE FAIRLY STRONG.
ACTIVITY WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST ON WEDNESDAY
EVENING AND THE REMAINDER OF SHORT TERM PERIOD WILL BE DRY. HIGHS
WILL FALL BACK INTO THE 70S FOR THURSDAY IN WAKE OF COLD FRONT.
STUCK WITH A MODEL BLEND FOR TEMPS THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MEMORIAL DAY/...
ISSUED AT 140 AM EDT TUE MAY 20 2014
MODELS AND REGIONAL BLEND IN GOOD AGREEMENT ON A DRY MEMORIAL DAY
WEEKEND...AND THIS LOOKS REASONABLE AS SURFACE HIGH PRESSURE BUILDS
IN FROM THE NORTHWEST ON FRIDAY AS AN UPPER LOW MOVES INTO THE
NORTHEASTERN STATES...AND AN UPPER RIDGE MOVES INTO THE PLAINS.
MODELS AND BLEND ALSO IN GOOD SHAPE ON TEMPERATURE TRENDS WITH COLD
ADVECTION AND 850 MILLIBAR TEMPERATURES FAVORING A SLIGHT COOL DOWN
COMPARED TO MIDWEEK WITH NEAR NORMAL AFTERNOON HIGHS IN THE LOWER TO
MID 70S LOOKING GOOD ON FRIDAY AND WARMING TO THE MID AND UPPER 70S
ON SUNDAY AND UPPER 70S AND MID 80S ON MEMORIAL DAY AS UPPER RIDGE
BUILDS IN FROM THE PLAINS AND SURFACE HIGH SHIFTS TO THE
SOUTHEASTERN STATES...WELL AHEAD OF A WESTERN FRONTAL SYSTEM.
&&
.AVIATION /DISCUSSION FOR 201800Z TAF ISSUANCE/...
ISSUED AT 114 PM EDT TUE MAY 20 2014
MAINLY VFR CONDITIONS THROUGHOUT THE PERIOD. POTENTIAL FOR
RESTRICTIONS WITHIN CONVECTION LATE TONIGHT AND EARLY WEDNESDAY.
EARLIER MID AND HIGH CLOUDS HAVE LARGELY SHIFTED EAST OF THE
TERMINALS EARLY THIS AFTERNOON. AS TEMPS HAVE SOARED INTO THE
70S...ALREADY SEEING CU DEVELOPMENT AND EXPECT IT TO EXPAND IN
COVERAGE THROUGH THE REMAINDER OF THE AFTERNOON. SOUTHWEST WIND
GUSTS UP TO 25KTS WILL BE POSSIBLE THROUGH EARLY THIS EVENING.
MAIN FOCUS OF THE FORECAST WILL BE CONVECTIVE POTENTIAL AND
POSSIBLE IMPACT TO TERMINAL OPS LATE TONIGHT INTO EARLY WEDNESDAY.
SHORT RANGE MODEL GUIDANCE SUPPORTING CONVECTIVE DEVELOPMENT
NORTHWEST OF THE REGION IN THE VICINITY OF THE COLD FRONT. WITH
THE EXCEPTION OF THE NAM...ALL MODEL DATA KEEPING CONVECTION
CONFINED NORTH OF THE REGION THROUGH 06Z...WITH SOUTHWARD
EXPANSION THEREAFTER AS THE STORMS COALESCE INTO A CONVECTIVE
COMPLEX. HAVE BACKED OFF VCTS ARRIVAL AT KHUF/KIND/KLAF BY SEVERAL
HOURS FROM PREVIOUS FORECAST. KBMG LIKELY TO BE FAR ENOUGH SOUTH
TO LIMIT ANY IMPACTS FROM A WEAKENING THUNDERSTORM CLUSTER. MVFR
AND LOWER RESTRICTIONS WILL BE POSSIBLE WITHIN THE STORMS LATE
TONIGHT AND WEDNESDAY MORNING.
MODEL SOUNDINGS SUPPORT SOME CLEARING BY MIDDAY WEDNESDAY WITH
WINDS VEERING TO A MORE WESTERLY DIRECTION AS THE COLD FRONT
SETTLES ACROSS CENTRAL INDIANA. RENEWED CONVECTIVE DEVELOPMENT
WEDNESDAY AFTERNOON EXPECTED AFTER 18Z FOCUSED ALONG AND SOUTH OF
I-70.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD/CP
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...RYAN
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FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
316 PM CDT TUE MAY 20 2014
.SYNOPSIS...
ISSUED AT 302 PM CDT TUE MAY 20 2014
COLD FRONT ACROSS IOWA WILL MOVE SOUTH OF THE STATE BY WED MORNING
AND BECOME STATIONARY TO THE SOUTH. HIGH PRESSURE EXPECTED TO
RIDGE INTO THE NORTH CENTRAL U.S. AND SETTLE OVER THE GREAT LAKES
BY THE WEEKEND. HIGH WILL FINALLY MOVE OFF SUNDAY WITH A
DEVELOPING FRONTAL SYSTEM IN THE ROCKIES MOVING TOWARD THE AREA
SUNDAY AND MONDAY.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 302 PM CDT TUE MAY 20 2014
BRIEF WINDOW FOR SEVERE CONVECTION LATE AFTERNOON INTO
THE EARLY EVENING HOURS AS STORMS WILL BE HIGHLY DEPENDENT ON
DAYTIME HEATING. FRONT REMAINS LAID UP ACROSS CENTRAL IOWA AND IS
ORIENTED FROM SW IOWA TOWARDS WATERLOO. VERY LITTLE...IF ANY SURFACE
CONVERGENCE OVER CENTRAL IOWA...WITH SOME CONVERGENCE PRESENT ACROSS
SOUTHWEST IOWA. AS OF 19Z...CAP IS BEGINNING TO SHOW SIGNS OF
ERODING AND MUCAPE VALUES HAVE INCREASED TO 2000 J/KG ACROSS
CENTRAL TO SOUTHERN IOWA. HOWEVER...THERE IS ABSOLUTELY NO 0-1KM BULK
SHEAR PRESENT AND THE DEEP LAYER SHEAR IS MARGINAL FOR SUSTAINABLE
UPDRAFTS. DCAPE VALUES RANGE FROM 900 TO 1100 J/KG ALONG AND SOUTH
OF THE FRONT...SO DOWNBURST THREAT IS VIABLE. IF STORMS DO
DEVELOP...STILL ANTICIPATING THE MAIN THREAT TO BE LARGE HAIL AND
DAMAGING WINDS. THE 20.15Z HOPWRF KEEPS CONVECTION INITIATION IN
EASTERN IOWA...WHILE THE 20.17Z HRRR IS MORE BULLISH WITH THE
CONVECTION DEVELOPING OVER WESTERN IOWA. THE SPC 20.12Z 4KM WRF
SEEMED LIKE A DECENT BLEND BETWEEN THE TWO. REGARDLESS...AS
MENTIONED...STORMS WILL BE HIGHLY SUNSHINE DEPENDENT AND NOT
EXPECTING CONVECTION TO LAST MUCH LATER THAN 02Z...WINDOW OF SEVERE
WEATHER OPPORTUNITY WILL BE FROM 21Z TO 02Z. HAVE SEVERE MENTION FOR
LIKELY POPS DURING THE AFOREMENTIONED TIME FRAME AND WENT DRY PAST
06Z TONIGHT FOR THE ENTIRE FORECAST AREA.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
ISSUED AT 302 PM CDT TUE MAY 20 2014
HIGH PRESSURE WILL NOSE INTO IOWA ON WEDNESDAY AND DOMINATE THE
WEATHER ACROSS THE STATE THROUGH THE REST OF THE WEEK. HIGH IS
LIKELY TO BECOME ANCHORED FOR A WHILE OVER THE COLD GREAT LAKES.
TYPICAL OF THIS TIME OF THE YEAR...BUT EVEN MORE LIKELY THIS YEAR
GIVEN THE COLDER THAN NORMAL WATER TEMPS AND THE PATTERN NOT IN AN
OVERLY PROGRESSIVE STATE.
AS THE HIGH BEGINS TO MOVE OFF AND LOSE ITS INFLUENCE
THUNDERSTORMS THAT WILL BE BRUSHING THE FAR SOUTHWEST PART OF IOWA
WILL BEGIN ADVANCING EAST. MODELS HAVE COME INTO CLOSER AGREEMENT
WITH THE OVERALL PROGRESSION. UPPER LOW WILL IMPINGE ON THE UPPER
RIDGE ADVERTISED IN THE MODELS IS ACCEPTED. A MILD AND WET PERIOD
IS ON TAP LOOKING AT THE BULK OF NEXT WEEK WITH THE SLOW MOVING
UPPER SYSTEM AND A NEGATIVE PNA SETTING UP.
&&
.AVIATION...20/18Z
ISSUED AT 1227 PM CDT TUE MAY 20 2014
MAIN CONCERN IS WITH CONVECTION DEVELOPING LATE THIS AFTERNOON
INTO THE EVENING HOURS AND WHICH TAF SITE IT WILL AFFECT. HAVE
THUNDER MENTIONED AT DSM/ALO/OTM PAST 23Z TODAY WITH THE BETTER
CHANCE OF STORMS AT ALO AND OTM. HOWEVER WITH THE ISOLATED NATURE
ANTICIPATED...LOW CONFIDENCE IN TIMING. OTHERWISE...KEPT
CONDITIONS VFR THROUGH TOMORROW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MS MAY 14
SHORT TERM...PODRAZIK
LONG TERM...MS MAY 14
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1230 PM CDT TUE MAY 20 2014
.SHORT TERM /TODAY/...
ISSUED AT 332 AM CDT TUE MAY 20 2014
ISOLATED CENTRAL IA THUNDERSTORM APPROACHING SEVERE LIMITS
DISSIPATED QUICKLY LAST HOUR. RAP SOUNDINGS SEEMED TO REFLECT THE
ENVIRONMENT QUITE WELL WITH POTENTIAL FOR STORMS ROOTED NEAR THE
SURFACE SHORTLY AFTER MIDNIGHT...BUT MLCINH INCREASING QUICKLY AS
BOUNDARY LAYER COOLS FURTHER AND DECOUPLING FINALLY TAKING PLACE.
WITH THIS PROGRESSION DO NOT REALLY EXPECT ANY ADDITIONAL
DEVELOPMENT UNTIL PEAK HEATING OF THE AFTERNOON...WHICH IS THE
PRIMARY FORECAST CONCERN.
SCENARIO FOR TODAY HAS CHANGED LITTLE OVER THE PAST FEW DAYS WITH
SEVERE WEATHER POTENTIAL STILL CONDITIONAL. MODELS ALL DEPICT
SIMILAR THERMODYNAMIC ENVIRONMENT WITH MLCINH ERODING DURING THE
AFTERNOON AND MLCAPES TO AROUND 1500 J/KG. HOWEVER WHILE THE CINH
HAS DIMINISHED SUFFICIENTLY FOR CONVECTION TO FIRE...LIMITING
FACTORS INCLUDE WEAK CONVERGENCE AND THE FACT THAT WARM 1-3KM
TEMPS WILL KEEP PARCELS FROM REALLY ACCELERATING UNTIL REACHING
3KM OR HIGHER. THERE IS A QUESTION WHETHER THE WEAK CONVERGENCE
WILL OVERCOME THIS. LARGE SCALE FORCING MAY HELP LIFT AND
DESTABILIZATION OF 1-3KM LAYER TOWARD 00Z HOWEVER AS CURRENT
DAKOTAS MN JET SEGMENT MOVES EASTWARD. THUS STILL HAVE SCATTERED
THUNDERSTORMS DEVELOPING IN THE EASTERN HIGHWAY 30/I80/HIGHWAY 92
CORRIDORS. MAIN SEVERE THREATS STILL APPEAR TO BE LARGE HAIL OR
WIND. LOW LEVEL SHEAR FAIRLY WEAK WITH HIGHER LCLS. STORM MOTION
WILL BE FAIRLY SLOW TOO BASED ON MEAN WIND AND BUNKERS
MOTION...LIKELY UNDER 25KTS.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 332 AM CDT TUE MAY 20 2014
THE SURFACE TROUGH SERVING AS A FOCUS FOR THUNDERSTORM DEVELOPMENT
THIS AFTERNOON...AS DISCUSSED IN THE SHORT TERM SECTION
ABOVE...WILL MOVE SOUTH OUT OF THE AREA TONIGHT WITH DECREASING
POPS OVERNIGHT. THEREAFTER...THE BOUNDARY WILL REMAIN OVER
MISSOURI WITH A LARGE SURFACE HIGH PRESSURE AREA BUILDING OVER
IOWA AND THE UPPER MIDWEST FOR SEVERAL DAYS. THIS WILL KEEP
TEMPERATURES RELATIVELY COOL TOWARD THURSDAY AND FRIDAY WITH RAIN
CHANCES REMAINING OVER MISSOURI OR POSSIBLY AFFECTING THE FAR
SOUTHERN FRINGE OF IOWA AT TIMES.
MEANWHILE...AT 500 MB A LARGE CUTOFF LOW WILL DEVELOP OVER THE
FAR SOUTHWEST U.S. LATE THIS WEEK AND RESIDE SOMEWHERE AROUND THE
CALIFORNIA/ARIZONA BORDER BY FRIDAY MORNING. THIS WILL SQUEEZE A
500 MB RIDGE DOWNSTREAM ACROSS THE CENTRAL U.S. AND UP TOWARD
IOWA. AS THE CUTOFF LOW SLOWLY MOVES EASTWARD THIS CENTRAL U.S.
RIDGE WILL STEADILY ERODE...ALLOWING THE UPPER MIDWEST SURFACE
RIDGE TO SLIDE EASTWARD WITH A RETURN OF SOUTHEAST SURFACE FLOW
OVER IOWA AND THE OLD FRONTAL BOUNDARY MOVING BACK OVERHEAD. THIS
WILL RESULT IN RAIN CHANCES RETURNING TO THE FORECAST AREA THIS
WEEKEND AND INTO EARLY NEXT WEEK...PERSISTING FOR MULTIPLE DAYS AS
THE 500 MB LOW MOVES INTO THE AREA THROUGH THE END OF THE SEVEN
DAY FORECAST PERIOD. CONSEQUENTLY FROM SATURDAY ONWARD GENERALLY
30 TO 40 POPS ARE CARRIED IN EVERY PERIOD WITH GRADUALLY
INCREASING TEMPERATURES.
&&
.AVIATION...20/18Z
ISSUED AT 1227 PM CDT TUE MAY 20 2014
MAIN CONCERN IS WITH CONVECTION DEVELOPING LATE THIS AFTERNOON
INTO THE EVENING HOURS AND WHICH TAF SITE IT WILL AFFECT. HAVE
THUNDER MENTIONED AT DSM/ALO/OTM PAST 23Z TODAY WITH THE BETTER
CHANCE OF STORMS AT ALO AND OTM. HOWEVER WITH THE ISOLATED NATURE
ANTICIPATED...LOW CONFIDENCE IN TIMING. OTHERWISE...KEPT
CONDITIONS VFR THROUGH TOMORROW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...LEE
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS TOPEKA KS
314 PM CDT Tue May 20 2014
.SHORT TERM...(This Evening through Wednesday)
Issued at 314 PM CDT TUE MAY 20 2014
The forecast seems to be unfolding as expected with the latest NAM
forecast soundings showing a capping inversion holding strong over
the area through the afternoon. 19Z water vapor imagery shows a
closed low over central CA with southwesterly flow aloft. There does
not appear to be much in the way of large scale forcing within the
upper flow, and low level convergence along an inverted surface
trough appears to be marginal with not much of a CU field in the
warm sector. The HRRR does try to bring convection off the higher
terrain to the west, but again shows it weakening due to the
elevated mixed layer before it reaches central KS. So expect a dry
forecast heading into Wednesday. Have trended lows tonight a couple
degrees cooler across northern KS. With the trough axis forecast to
pivot more west to east across the forecast area, winds are likely
to become light. This combined with mostly clear skies should allow
for some decent radiational cooling and lows in the lower 60s across
the northern counties. East central KS is likely to stay south of
the trough axis in the warmer air with higher dewpoints so have kept
lows in the mid to upper 60s.
For Wednesday, models are in agreement that the weak boundary will
be across the area with good moisture pooling along it. The NAM and
GFS warm the boundary layer enough so that CAPE values increase to
3000 or 3500 J/kg. They also cool mid levels some so that there is
very little or no CIN by the mid afternoon. Large scale forcing
continues to look unimpressive, but there could be enough
convergence along the boundary for some isolated storms to develop
by the late afternoon. Deep layer shear of 40 to 50 KTS also suggest
that if storms are able to form, they could become supercellular. At
this point low level shear parameters show little or no chance for
tornadoes so main risks with storms that form would be a hail and
wind. Highs Wednesday should not be quite as warm as models weaken
the thermal ridge over the area. Because of this highs are forecast
to be in the middle and upper 80s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 314 PM CDT TUE MAY 20 2014
Somewhat above normal thunderstorm chances continue to dominate the
middle and later portions of the forecast. Have shaded chances
slightly up and down when some confidence exists in possible
evolution, but overall confidence on timing and placement of precip
not high.
Wednesday night into Thursday night still present the more dynamic
storm periods with the stationary front keeping some minor
baroclinicity. Any local afternoon storms could easily persist in
the evening hours and keep at least modest severe weather potential,
but highest coverage for overnight Wednesday night into early
Thursday still at least moderately dependent on where convection can
be the most robust and organized to the west. Models differ on
where this will be, but some indications this could be a bit farther
south than earlier anticipated. A rather warm and moist boundary
layer should keep low-level parcels rather buoyant and NAM and GFS
agree with limited CIN through Wednesday night for at least some
severe potential. Synoptic surface high to the northeast and low the
southwest should keep at lest some low-level convergence intact for
Thursday afternoon over the area as long as overnight and early day
convection does not displace the effective front elsewhere. Corfidi
vectors turn more southeast and again may be rather parallel to the
front for overnight convection to again pass through. By Friday
afternoon, more meridional low level flow takes hold for the Central
Plains and should greatly reduce convergence, again barring
MCS-dominated surface features. GFS and ECMWF are rather consistent
with an upper wave emerging from the old trough, but this appears to
be at least partially due to previous convection. Despite weakening
mid-level lapse rates, instability should continue to be at least
modest with good moisture through the column for some storm chances
into Sunday. Better dynamic forcing aloft could commence Sunday
night into Tuesday afternoon if the GFS and ECMWF are correct with
the low finally pushing through, but of course timing ejection of
cut-off lows is difficult at best. Little change in temperatures is
forecast, but again highs will be greatly impacted by any persistent
MCS that persists.
&&
.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1200 PM CDT TUE MAY 20 2014
A capping inversion is expected to prevent any convection from
developing this afternoon. Therefore VFR conditions should
prevail. The surface trough axis should move over the terminals
overnight causing winds to become light and variable.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...65
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS JACKSON KY
147 PM EDT TUE MAY 20 2014
.UPDATE...
ISSUED AT 1100 AM EDT TUE MAY 20 2014
EXCEPT FOR A FEW MINOR EDITS...THE FORECAST APPEARS ON TRACK TODAY.
NOTICE A FEW ECHOES ON RADAR NEAR CVG ASSOCIATED WITH THE WEAK WARM
FRONT MOVING ACROSS THE REGION AT THIS TIME. NEAR TERM MODEL
GUIDANCE INCLUDING LATEST HRRR KEEPS ANY SHOWER ACTIVITY JUST TO OUR
NORTH SO WILL MONITOR UPSTREAM DEVELOPMENTS CLOSELY BUT MAINTAIN A
DRY FORECAST FOR THE REST OF THE DAY AT THIS TIME.
UPDATE ISSUED AT 726 AM EDT TUE MAY 20 2014
MADE A FEW TWEAKS TO THE CLOUD COVER FORECAST FOR THE REST OF TODAY
INTO EARLY THIS EVENING. SATELLITE IMAGERY AND DIRECT OBSERVATION
REVEALED THAT CLOUDS ARE A BIT MORE EXTENSIVE ACROSS EASTERN KENTUCKY
THAN THE FORECAST HAD BEEN REFLECTING. INCREASED CLOUD COVER ACROSS
THE AREA THROUGH EARLY THIS EVENING TO ACCOUNT FOR THIS. ALSO
INGESTED THE LATEST OBS DATA TO ESTABLISH NEW TRENDS IN HOURLY
TEMPERATURES AND WINDS FOR TODAY. THE REST OF THE FORECAST WAS IN
GOOD SHAPE WITH NO OTHER CHANGES NEEDED. THE ZONE FORECAST TEXT
PRODUCT WAS ALSO GOOD AS IS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 323 AM EDT TUE MAY 20 2014
THE MODELS IN GENERAL WERE IN PRETTY GOOD AGREEMENT IN THE SHORT
TERM. THE OVERALL CONSENSUS IS FOR A RIDGE OF HIGH PRESSURE TO REMAIN
IN PLACE TODAY AND TONIGHT...BRINGING WARM AND DRY WEATHER TO THE
REGION. THE RIDGE WILL BEGIN TO BREAK DOWN AND MOVE OFF TO THE SOUTH
LATE IN THE DAY ON WEDNESDAY...AS A COLD FRONT PUSHES SOUTHWARD OUT
OF THE OHIO VALLEY AHEAD OF A SOUTHWARD MOVING RIDGE OF CANADIAN HIGH
PRESSURE. SHOWERS AND STORMS WILL BEGIN TO BREAK OUT ALONG THE FRONT
LATE WEDNESDAY MORNING AS THE FRONT FIRST BEGINS TO MOVE INTO THE
AREA. THESE SHOWERS AND STORMS WILL BECOME MORE NUMEROUS DURING THE
AFTERNOON AND EVENING HOURS DURING PEAK HEATING AS THE FRONT MOVES
ACROSS THE AREA. THE LATEST MODEL SOUNDINGS...PARTICULARLY THE
NAM12...ARE SHOWING A PERIOD OF PRETTY GOOD INSTABILITY ACROSS THE
AREA WEDNESDAY AFTERNOON. WITH THE FRONT MOVING THROUGH DURING THIS
TIME...AND WITH SOME DECENT MOISTURE OFF THE GULF OF MEXICO ALREADY
OVER THE AREA...SOME OF THE STORMS ON WEDNESDAY COULD APPROACH SEVERE
LIMITS...WITH DAMAGING WINDS BEING THE MAIN THREAT.
TEMPERATURES DURING THE PERIOD WILL BE RUNNING A GOOD DEAL ABOVE
NORMAL...WITH HIGHS TODAY AND TOMORROW LIKELY TOPPING OUT IN THE 80S
PRETTY MUCH EVERYWHERE. OVERNIGHT LOWS WILL ONLY MAKE INTO THE LOWER
60S FOR MOST FOLKS...AS GOOD MOISTURE RETURN OFF THE GULF KEEP THE
AIR MOIST ENOUGH TO NOT ALLOW FOR THE TYPES OF TEMPERATURE DROPS WE
HAVE EXPERIENCED THE PAST FEW NIGHTS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM EDT TUE MAY 20 2014
THE MODELS ARE IN GOOD AGREEMENT WITH A BLOCKY LONG WAVE PATTERN
ACROSS THE CONUS THROUGH THE EXTENDED. A CA/NV UPPER LEVEL LOW WILL
SLOWLY MOVE EAST INTO THE PLAINS...WHILE A TROUGH BECOMES REINFORCED
OFF OF THE EASTERN SEABOARD. A RIDGE AXIS WILL BE SANDWICHED IN
BETWEEN THE TWO TROUGHS...SLOWLY SHIFTING FROM THE PLAINS TO THE
MISSISSIPPI VALLEY THROUGH THE PERIOD.
WEDNESDAY NIGHT WILL START OUT A BIT STORMY ACROSS THE AREA...AS A
COLD FRONT SAGS SOUTHWARD TOWARDS EASTERN KENTUCKY ALONG WITH A PASSING
SHORT WAVE TROUGH IN UPPER LEVEL NORTHWEST FLOW. MCS ACTIVITY APPEARS
LIKELY SOMEWHERE IN THE OHIO VALLEY...WITH AN ONGOING SEVERE WEATHER
THREAT LINGERING INTO AT LEAST THE FIRST PART OF THE NIGHT.
THE BOUNDARY WILL CONTINUE TO SAG SOUTH DURING THE DAY ON
THURSDAY...ALTHOUGH INSTABILITY WILL NOT BE AS STOUT...SO ANY
SCATTERED CONVECTION SHOULD BE MORE TAME DURING THE AFTERNOON. ONCE
THE STORMS WANE THROUGH THE EVENING...DRY WEATHER IS EXPECTED TO
ENSUE THEREAFTER...AS THE UPPER LEVEL RIDGE AXIS GRADUALLY SHIFTS
OVERHEAD THROUGH EARLY NEXT WEEK.
HIGHS ON THURSDAY WILL TOP OUT NEAR 80...BEFORE COOLING OFF TO THE
MID AND UPPER 70S BEHIND THE FRONT ON FRIDAY AND SATURDAY. HIGHS WILL
THEN WARM THROUGH EARLY NEXT WEEK...REACHING THE LOW TO MID 80S BY
MONDAY. LOWS WILL AVERAGE IN THE 50S...ALTHOUGH A FEW SHELTERED
VALLEYS MAY GET DOWN INTO THE UPPER 40S FRIDAY AND SATURDAY NIGHTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 147 PM EDT TUE MAY 20 2014
SOUTHWEST FLOW AROUND HIGH PRESSURE OVER THE DEEP SOUTH WILL
CONTINUE ACROSS EAST KENTUCKY OVER THE NEXT 24 HOURS. VFR CONDITIONS
ARE FORECAST BUT GUSTY SOUTHWEST WINDS WILL CONTINUE THIS
AFTERNOON...STRONGEST AT LOZ AND SME...AND THEN REDEVELOP AGAIN
AFTER 14Z TOMORROW. EVEN THOUGH WINDS WILL SUBSIDE AFTER SUNSET THIS
EVENING...ENOUGH MIXING SHOULD OCCUR TO PRECLUDE ANY FOG
DEVELOPMENT. A COLD FRONT WILL THEN SAG SOUTH INTO THE OHIO VALLEY
ON WEDNESDAY AND MODELS INDICATE A CLOUD DECK AROUND 4-5K FT WILL
INTRUDE FROM THE NORTHWEST NEAR DAWN. THIS SHOULD BE THE ONLY IMPACT
ON OUR AREA FROM THIS FRONT THROUGH 18Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR/ABE
SHORT TERM...AR
LONG TERM...GEOGERIAN
AVIATION...ABE
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
345 PM EDT TUE MAY 20 2014
.SHORT TERM... THROUGH TONIGHT
SHORT TERM CONCERNS STILL REVOLVE AROUND CONVECTIVE TRENDS AND
POTENTIAL FOR SEVERE WEATHER. FIRST...FOR THE REMAINDER OF THIS
AFTERNOON INTO THE EVENING. FAST ZONAL UPPER LEVEL FLOW IS OVER THE
UPPER MIDWEST BETWEEN A RIDGE OVER THE SOUTHERN PLAINS AND A TROUGH
OVER SOUTHERN MANITOBA/SOUTHWESTERN ONTARIO. 18Z SURFACE ANALYSIS
SHOWED A WARM FRONT ARCING SE INTO MICHIGAN FROM ROUGHLY NORTH OF
MUSKEGEON TO LAPEER AND THEN SOUTH TO AROUND MONROE. THE
NORTH/EASTWARD PROGRESS OF THE FRONT IS BEING HINDERED BY FLOW OFF
THE COOLER LAKES. TEMPS CONTINUE TO WARM INTO THE LOW/MID 70S SOUTH
OF THE FRONT WITH DESPOINTS IN THE LOW 50S TO NEAR 60. SOME CUMULUS
IS DEVELOPING OVER SOUTHWESTERN LOWER IN THE LEE OF LAKE
MICHIGAN...BUT SO FAR IT IS SHALLOW. MIDLEVEL LAPSE RATES ARE FAIRLY
MEAGER BUT SHOULD INCREASE INTO THE EVENING. SOME MODEST SURFACE
BASED INSTABLITY MAY DEVELOP AS WE GET LATER INTO THE AFTERNOON AND
EVENING. DEEP LAYER SHEAR OF 35-50KT IS FAVORABLE FOR ORGANIZED
CONVECTION SHOULD ANYTHING DEVELOP...BUT THE LACK OF CLEAR FORCING
MECHANISMS AND GREATER INSTABILITY WILL KEEP POPS IN THE LOW CHANCE
RANGE THROUGH 00Z.
ANOTHER THREAT IS EXPECTED TO DEVELOP AFTER 04Z...BUT IT
IS FAR FROM CERTAIN. DISCRETE CELLS ARE EXPECTED TO DEVELOP OVER
NORTHERN ILLINOIS LATE THIS AFTERNOON. THESE STORMS MAY EVOLVE INTO
ONE OR MORE FORWARD-PROPAGATING QUICK-MOVING MCS...WHICH COULD BE
LONG-LIVED DUE TO CONTINUED STRONG DEEP-LAYER SHEAR AND APPRECIABLE
INSTABILITY. THIS SCENARIO IS SUPPORTED BY THE 16Z HRRR AND THE 12Z
NMM. THESE COMPLEXES WOULD PREFERENTIALLY MOVE TOWARD THE RESERVOIR
OF GREATER INSTABILITY...WHICH IS BETTER TO OUR SOUTH WHERE THE
GREATER MIDLEVEL LAPSE RATES WILL RESIDE. STILL...THE THREAT IS GOOD
ENOUGH TO INCLUDE A SLIGHT CHANCE OF SEVERE WEATHER FROM M-59 SOUTH
/WITH THE BEST CHANCES NEAR THE OHIO BORDER/ FROM AROUND 04-10Z.
DAMAGING WIND WOULD BE THE MAIN THREAT...WITH LARGE HAIL AND AN
ISOLATED TORNADO SECONDARY. HEAVY RAIN IS ALSO POSSIBLE AS PWATS
INCREASE TO 1.3-1.5 INCHES.
&&
.LONG TERM...
LARGE UPPER LEVEL LOW SLOWLY WORKING THROUGH ONTARIO
TOMORROW...DROPPING SOUTHEAST INTO NEW ENGLAND THURSDAY NIGHT INTO
FRIDAY WILL DELIVER A RESPECTABLE SHOT OF COOL AIR TO SOUTHEAST
MICHIGAN THURSDAY INTO FRIDAY...BEFORE TEMPERATURES QUICKLY MODERATE
OVER THE WEEKEND AS AMPLIFIED UPPER LEVEL RIDGE BUILDS INTO THE
GREAT LAKES REGION...LIKELY LEADING TO EVEN WARMER TEMPERATURES (80+
DEGREES) EARLY NEXT WEEK.
AS FAR AS TOMORROW GOES...THE FORECAST WILL BE IMPACTED WITH WHAT
OCCURS OVERNIGHT...AS POTENTIAL DEPARTING MCV MAY CAST
SHADOW/SUBSIDENCE WAKE THROUGH A GOOD PORTION OF THE DAY.
OTHERWISE...DO HAVE SHORTWAVE TROUGH AXIS EXTENDING FROM THE
PREVIOUS MENTIONED UPPER LEVEL LOW OVER ONTARIO...WHICH WILL CAUSE
SURFACE COLD FRONT TO SWING THROUGH DURING THE PEAK DIURNAL CYCLE.
STRONG WESTERLY JET (65 KNOTS AT 500 MB) CORE WILL BRING AN
INCREASED RISK OF DAMAGING WINDS IF THUNDERSTORMS ARE ABLE TO
DEVELOP DURING THE AFTERNOON HOURS. THE PROBLEM IS WE CAN NOT FULLY
COUNT ON A MORNING CAP/LULL...AND STORMS COULD EASILY DEVELOP
EARLIER IN THE DAY. DURING THE AFTERNOON HOURS...THE INCREASING
MIXING DEPTHS WE ACCELERATE THE WESTERLY DRYING OUT
PROCESS...LEADING TO QUESTIONS WITH THE AREAL COVERAGE OF THE
POTENTIAL STORMS DEVELOPING ALONG THE COLD FRONT...AS MAX
INSTABILITY LOOKS TO BE OVER THE NORTHERN OHIO VALLEY. WITH THAT
SAID...IT LOOKS FAIRLY LIKELY SOMETIME DURING THE 12 HOUR
WINDOW...NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR...AND
UNFORTUNATELY WILL CARRY GENERIC HIGH SCATTERED/LOW LIKELY POPS
THROUGH THE DAY...AS TONIGHT`S EVOLUTION WILL BE A ONE OF THE KEYS
FOR TOMORROWS WEATHER.
STRONG NORTHWEST FLOW WEDNESDAY NIGHT INTO THURSDAY...WITH 850 MB
TEMPS FALLING INTO THE MID SINGLE NUMBERS. THE CYCLONIC/COLD
ADVECTION AND STEEP LOW LEVEL LAPSE RATES SHOULD BE SUFFICIENT TO
GENERATE PLENTY OF CLOUDS DURING THE DAYTIME HOURS OF
THURSDAY...LIKELY CAPPING MAXES IN THE UPPER 60S TO AROUND 70
DEGREES. ANOTHER PIECE OF ENERGY ROTATING SOUTH THROUGH THE CENTRAL
GREAT LAKES ON FRIDAY SHOULD MAINTAIN THE COOLER TEMPERATURES AND
CONSIDERABLE CLOUDS DURING THE DAYTIME HOURS...AND EVEN SUFFICIENT
DIURNAL INSTABILITY/CAPES/CLOUD DEPTHS (4-12 KFT) TO POSSIBLY
PRODUCE ISOLATED LIGHT SHOWERS.
12Z EURO IS IN DECENT AGREEMENT WITH THE CANADIAN/GFS IN BUILDING
UPPER LEVEL RIDGE OVER THE CENTRAL GREAT LAKES ON
MONDAY...SUPPORTING HIGHS IN EXCESS OF 80 DEGREE WITH INCREASING
SOUTHWEST FLOW AND 850 MB TEMPS WARMING INTO THE MID TEENS INTO
TUESDAY.
&&
.MARINE...
INCREASED SOUTHEAST FLOW OVER OUTER SAGINAW BAY AND THE ADJACENT
NEARSHORE WATERS DUE TO THUNDERSTORMS TRACKING THROUGH THE AREA WILL
DIMINISH AS WARM FRONT WEAKENS TONIGHT. A STRONG COLD FRONT WILL
SWING THROUGH THE CENTRAL GREAT LAKES TOMORROW AFTERNOON...WITH
BRISK NORTHWEST WINDS FOLLOWING FOR WEDNESDAY NIGHT AND THURSDAY.
ANY THUNDERSTORMS WHICH DEVELOP TONIGHT THROUGH TOMORROW MAY BE
STRONG TO SEVERE. COOLER AND MORE STABLE AIRMASS WILL FILTER INTO
THE REGION THURSDAY AND FRIDAY...BUT ISOLATED SHOWERS ARE STILL
POSSIBLE. A LARGE UPPER LEVEL RIDGE BUILDING INTO THE GREAT LAKES
REGION OVER THE WEEKEND WILL LEAD TO WARMUP TEMPERATURES AND LIGHT
WINDS.
&&
.AVIATION...ISSUED 200 PM EDT TUE MAY 20 2014
//DISCUSSION...
VFR CONDITIONS FOR MUCH OF THE AFTERNOON AND EVENING AS SKIES ARE
CLEARING OUT WITH A WARM FRONT LIFTING INTO SOUTHWEST MICHIGAN.
THERE IS A SLIGHT CHANCE THAT SOME STORMS WILL FIRE ALONG THE FRONT
TO OUR WEST AND TRACK INTO THE AREA BUT CHANCES ARE TOO LOW TO
MENTION IN THE TAFS AT THIS TIME. THE BETTER CHANCE FOR
SHOWERS/THUNDERSTORMS WILL BE OVERNIGHT AS MODELS INDICATE A MCS
DEVELOPING AND TRACKING ACROSS SOUTHERN MICHIGAN. CONDITIONS WILL
DETERIORATE WITH THE ADDITIONAL MOISTURE AND PRECIPITATION IN THE
AREA. EXPECT MVFR/IFR CONDITIONS FROM 05Z UNTIL AROUND DAYBREAK
WEDNESDAY WHEN WE START BURNING OFF SOME RESIDUAL MOISTURE.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILING BELOW 5000 FEET AFTER 05Z TONIGHT.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...DT
LONG TERM....SF
MARINE.......SF
AVIATION.....DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
110 PM EDT TUE MAY 20 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 506 AM EDT TUE MAY 20 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A SHORTWAVE TROUGH MOVING
THROUGH NRN WI IN WRLY FLOW BETWEEN A LOW OVER SE SASK AND A RIDGE
OVER THE LOWER MS VALLEY. AT THE SFC...AN OCCLUDED FRONT EXTENDED
FROM THROUGH WRN MN FROM LOW PRES OVER SRN MANITOBA. STRONG
300K-305K ISENTROPIC LIFT NORTH OF AN 850 MB WARM FRONT OVER NRN WI
SUPPORTED SHOWERS ACROSS MOST OF UPPER MI. A FEW TSRA FROM NRN WI
WERE MOVING INTO WRN UPPER MI WHERE MUCAPE VALUES WERE NEAR 500
J/KG.
TODAY...EXPECT THE PCPN TO DEPART FROM WEST TO EAST THIS MORNING AS
THE SHORTWAVE TROUGH AND STRONGER ISENTROPIC LIFT MOVE OUT AND MID
LEVEL DRYING TAKES OVER. THE BEST CHANCE FOR TSRA SHOULD REMAIN OVER
THE SOUTH NEAR THE AXIS OF STRONGER MUCAPE. WITH MAINLY DRY
CONDITIONS DURING THE AFTERNOON...TEMPERATURES SHOULD REBOUND INTO
THE 60S TO NEAR 70...WARMEST NEAR THE WI BORDER.
TONIGHT...AS A SHORTWAVE TROUGH SLIDES TO THE EAST FROM NE NORTH
DAKOTA TO NRN LAKE SUPERIOR MODERATE 700-300 QVECTOR CONV AND UPPER
LEVEL DIV WITH THE LEFT EXIT OF THE 250-300 MB JET WILL SUPPORT A
CHANCE OF SHOWERS THROUGH THE CWA MAINLY AFT 06Z...WITH THE HIGHEST
POPS ACROSS THE NORTH. INCREASING MID LEVEL LAPSE RATES AND FCST
MUCAPE VALUES IN THE 400-800 J/KG RANGE SHOULD ALSO SUPPORT A FEW
TSRA.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 303 AM EDT TUE MAY 20 2014
AT 12Z WEDNESDAY THE MAIN 500MB LOW WILL BE SITUATED ACROSS ONTARIO
WITH A SHORTWAVE/TROUGH EXTENDING ACROSS MN. LOOK FOR THIS FEATURE
TO CROSS UPPER MI THROUGH THE DAY. THE SFC LOW OVERHEAD WITH IT/S
OCCLUDED FRONT AT 12Z WILL QUICKLY EXITING E /ACROSS FAR E UPPER MI
AT 18Z/. DESPITE THE EXITING LOW A FEW SHOWERS WILL STILL BE
POSSIBLE WEDNESDAY-WEDNESDAY NIGHT...WHEN HIGH PRESSURE BUILDS IN AT
THE SFC AND ALOFT.
AS FOR SOME OF THE SMALL-SCALE FEATURES OF INTEREST...NW WINDS
SHOULD BECOME GUSTY WEDNESDAY AFTERNOON THROUGH THURSDAY. PW VALUES
STILL LOOK TO FALL TO AROUND 0.5IN /55 PERCENT OF NORMAL/ OVER THE W
HALF OF UPPER MI WEDNESDAY AFTERNOON THROUGH THE END OF THE WORK
WEEK. WILL NEED TO MONITOR THOSE AREAS THAT MAY NOT RECEIVE AS MUCH
RAIN FOR FIRE WX CONCERNS UNTIL THE WINDS DIMINISH THURSDAY EVENING
THROUGH FRIDAY AS THE SFC HIGH EXTENDING FROM S LAKE HURON AND THE N
PLAINS SLIPS DIRECTLY OVERHEAD.
HIGH TEMPERATURES WILL RETURN BACK TO SEASONAL NORMAL VALUES FOR
FRIDAY UNDER A MOSTLY SUNNY SKY...WITH 60S FOR MOST AREAS AND A FEW
POCKETS OF 70 DEGREE READINGS OVER THE INTERIOR W HALF.
THE CENTER OF THE SFC HIGH WILL SLIP JUST TO THE E OF UPPER MI
SATURDAY AFTERNOON. 850MB TEMPS WILL JUMP APPROX 2C FROM AROUND 8C
FRIDAY AFTERNOON TO 11C SATURDAY AS SW WINDS AND INCREASED MOISTURE
MAKE A RETURN TO THE CWA. THE WARMEST DAY LOOKS TO BE SUNDAY AS
850MB TEMPS RISE TO AROUND 15C AT 850MB ON 20KT SW FLOW. UPPER 70S
WILL BE POSSIBLE OVER THE INTERIOR W HALF OF UPPER MI...WHICH MAY
GLIDE TO THE DOWNSLOPE AREAS OF THE N CENTRAL CWA ALONG LAKE
SUPERIOR /ASSUMING LITTLE TO NO LAKE BREEZE POTENTIAL OFF LAKE
SUPERIOR/. ONE THING THAT COULD KNOCK THE TEMPS DOWN A BIT OVER THE
W HALF WOULD BE APPROACHING RAIN SHOWERS /AND ISOLATED TS/ AS THE
ELONGATED SFC LOW STRETCHING ACROSS THE PLAINS AND W ONTARIO NEARS.
THE 500MB LOW OVER CENTRAL CA TODAY WILL SPIN ACROSS THE 4-CORNERS
REGION ON SATURDAY...BEFORE SLOWLY EJECTING NE TO THE CENTRAL PLAINS
BY THE END OF THE DAY MONDAY. THE 500MB RIDGE WILL REMAIN EITHER
JUST W OR OVER THE UPPER GREAT LAKES THROUGH 00Z SUNDAY. THE
POTENTIAL FOR UNSETTLED WEATHER WILL RETURN TO END THE WORK WEEK.
KEPT THE SLIGHT CHANCE OF TS IN THE FCST FOR LATE SUNDAY AFTERNOON
THROUGH MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 109 PM EDT TUE MAY 20 2014
CONDITIONS WILL SLOWLY IMPROVE THIS AFTERNOON AS DRIER AIR SLOWLY
MOVES INTO THE AREA AND HELPS TO DISSIPATE THE FOG AT CMX AND RAISE
THE CIGS AT IWD AND SAW. CONDITIONS WILL GO TO VFR BY LATE AFTERNOON
INTO EARLY EVENING AT ALL SITES. NEXT WAVE OF RAIN MOVES IN LATE
OVERNIGHT AND CONDITIONS WILL GO BACK TO MVFR OR IFR AT ALL THE
SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 506 AM EDT TUE MAY 20 2014
SE WINDS OF 15 TO 25 KNOTS OVER THE ERN PORTION OF THE LAKE WILL
DIMINISH THIS AFTERNOON AND REMAIN AT OR BELOW 20 KNOTS THROUGH
SATURDAY AS A MAINLY STABLE MARINE LAYER WILL PREVAIL. WITH THE RAIN
AND INFLUX OF LOW LEVEL MOISTURE INTO THE REGION...SOME FOG MAY
DEVELOP FROM TODAY INTO WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
312 PM CDT TUE MAY 20 2014
.SYNOPSIS...
ISSUED AT 312 PM CDT TUE MAY 20 2014
A FAIRLY ACTIVE H5 PATTERN HAS DEVELOPED ACROSS THE
CONUS OVER THE PREVIOUS 24 HOURS. LOW PRESSURE WAS ANCHORED OFF THE
COAST OF MAINE...WITH ANOTHER LOW OVER NORTHERN PORTIONS OF THE
CENTRAL VALLEY OF CALIFORNIA. ANOTHER LOW WAS PRESENT OVER THE
ALASKA PANHANDLE WITH ANOTHER LOW OVER NORTHERN PORTIONS OF THE
NORTHWEST TERRITORIES OF CANADA. CLOSER TO THE CENTRAL CONUS...A
NICE SHORTWAVE TROUGH WAS NOTED OVER SWRN MANITOBA. A 50+KT JET
STREAK EXTENDED ACROSS NRN WYOMING INTO SOUTH DAKOTA AND CENTRAL
MINNESOTA THIS MORNING. THIS FEATURE HAS LED TO THE DEVELOPMENT OF
SOME LIGHT RAIN SHOWERS ACROSS NORTHERN NEBRASKA AND SRN SOUTH
DAKOTA. THIS ACTIVITY HAS REMAINED VERY LIGHT THIS MORNING WITH ONLY
TRACE AMOUNTS TO A FEW HUNDREDTHS OF AN INCH REPORTED. AT THE
SURFACE...A TROUGH OF LOW PRESSURE EXTENDED FROM SERN MONTANA INTO
NERN COLORADO. FURTHER EAST...A COLD FRONT EXTENDED FROM FAR SWRN
NEBRASKA INTO THE SOUTHERN TEXAS PANHANDLE. TEMPERATURES SOUTH OF
THIS FEATURE WERE IN THE MID 80S TO 90S. WEST AND NORTH OF THE
FRONT...READINGS WERE IN THE 70S TO LOWER 80S. AS OF 2 PM
CDT...TEMPERATURES ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...RANGED FROM 73 AT VALENTINE...TO 83 AT BROKEN BOW.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 312 PM CDT TUE MAY 20 2014
ALTOCUMULUS AND SPRINKLES BISECTING THE LBF CWA A RESULT OF REMNANTS
OF EARLIER CONVECTION AND WEAK MID LEVEL FORCING IN ASSOCIATION WITH
MID LEVEL INSTABILITY. SUBSEQUENT MID LEVEL FRONTOGENESIS HAS
DEVELOPED ACCORDING TO THE RAP FURTHER SOUTHEAST IS GENERATING SOME
ADDITIONAL CLOUD COVER ACROSS THE FAR EASTERN PORTION OF THE AREA.
FURTHER WEST...CONVECTION IS DEVELOPING NEAR THE LARAMIE RANGE IN WY
VERY SIMILAR TO THE WAY CONVECTION ALLOWING MODELS HAVE BEEN
SUGGESTING WITH EACH RUN. THE HRRR HAS THIS HANDLED WELL AND IN THE
ABSENCE OF SIGNIFICANT LARGE SCALE FORCING...THIS CONVECTION IS
PROGGED TO REMAIN ISOLATED AND DOES HAVE SOME POTENTIAL TO RETAIN
SUPERCELL STRUCTURE AS IT MOVES EAST INTO THE PANHANDLE THIS
EVENING...AGAIN ACCORDING TO THE HRRR AND ITS ENSEMBLE OF UPDRAFT
HELICITY. SHOULD THIS CLUSTER OF STORMS HOLD TOGETHER TONIGHT THERE
IS SOME SUPPORT IN THE SHORT RANGE MODELS FOR ELEVATED INSTABILITY
IN THE PANHANDLE. FURTHER SOUTH INTO SOUTHWEST NEB...SOME CONVECTION
DEVELOPING NEAR THE CO FRONT RANGE AND MODELS KEEP THIS PROGRESSING
EWD AS WELL SO PRECIP CHANCES ADDED TO THE SOUTHWEST OVERNIGHT.
HOWEVER...CONFIDENCE IN THIS SCENARIO IS ONLY MODERATE TO MAINTAIN
ITS STRUCTURE INTO THE SW DUE TO A LACK OF A LOW LEVEL JET.
OTHERWISE...LOW TEMPS IN THE UPPER 40S TO LOW 50S LOOKS GOOD BASED
ON LOW LEVEL MOISTURE PROFILE BEING MAINTAINED OVERNIGHT.
UPPER LEVEL RIDGE BUILDS INTO THE CENTRAL PLAINS AS THE SOUTHWESTERN
STATES UPPER LOW SLOWLY MOVES EWD. MAY BE SOME CONVECTIVE DEBRIS
ONCE AGAIN WED MORNING ESPECIALLY ACROSS WRN NEB. IN ADDITION...NAM
SUGGESTS POTENTIAL FOR STRATUS ALONG AND JUST EAST OF THE FRONTAL
POSITION IN FAVORED AREA OF UPSLOPE FLOW. THEN UPPER PV ANOMALY TO
MOVE INTO THE CENTRAL ROCKIES TOMORROW WHICH SHOULD ALLOW FOR A MUCH
BROADER COVERAGE OF CONVECTION AS THE UPPER FORCING SERVES TO
ENHANCE CONVERGENCE ALONG THE FRONT WHICH WILL BE LOCATED FROM NW KS
IN TO SERN WY. THIS DEVELOPMENT SHOULD BE DIURNALLY DRIVEN AND MAY
BE LIMITED DEPENDING ON ULTIMATE DEVELOPMENT OF STRATUS IN THE WEST.
TEMPS SHOULD BE COOLER WED THOUGH MODELS HAVE BEEN A LITTLE TOO COOL
IN THE SOUTH THE LAST COUPLE OF DAYS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 312 PM CDT TUE MAY 20 2014
WEDNESDAY NIGHT THROUGH TUESDAY...THE MAIN FORECAST
CHALLENGE WILL BE PRECIPITATION CHANCES IN THE MID RANGE AND
EXTENDED FORECAST. A PERSISTENT UPPER LEVEL TROUGH OF LOW PRESSURE
WILL REMAIN ANCHORED ACROSS THE WESTERN CONUS. PERSISTENT LOW LEVEL
MOISTURE WILL FLOW INTO WESTERN AND NORTH CENTRAL NEBRASKA THANKS TO
LOW LEVEL EASTERLY WINDS.
FOR WEDNESDAY NIGHT THROUGH FRIDAY...WEDNESDAY NIGHT...STRONG TO
SEVERE STORMS ARE EXPECTED TO BE ONGOING ACROSS NERN COLORADO AND
NWRN KS INVOF OF THE SURFACE FRONTAL BOUNDARY. WITH SSWRLY STEERING
WINDS CONTINUING ACROSS THE HIGH PLAINS...ACTIVITY WILL LIFT NWD
INTO THE FORECAST AREA DURING THE EVENING HRS. THERE WILL REMAIN A
LARGE HAIL THREAT MAINLY ACROSS FAR SWRN NEBRASKA AND THE SERN
NEBRASKA PANHANDLE WHICH WILL BE IN CLOSER PROXIMITY TO THE FRONTAL
BOUNDARY. FARTHER NORTH...HAIL SIZE SHOULD DECREASE ACROSS THE
WESTERN SANDHILLS AND I80 CORRIDOR...HOWEVER SMALL HAIL WILL REMAIN
A THREAT GIVEN THE DEGREE OF ELEVATED INSTABILITY EXPECTED
OVERNIGHT. BOTH THE GFS AND NAM SOLNS THIS MORNING...ARE INDICATIVE
OF MCS DEVELOPMENT WEDS EVENING...WHICH WILL TRAVERSE THE CWA
OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN THE 30 TO 40 KT H85 WINDS
ACROSS THE SOUTHERN AND CENTRAL CWA OVERNIGHT WEDS NIGHT. INHERITED
FORECAST HAD POPS IN THE 30 TO 50 PERCENT RANGE FROM NORTH TO SOUTH
WEDS NIGHT WHICH REMAINS ON TRACK GIVEN THE LATEST STATISTICAL
GUIDANCE. A SIMILAR CONVECTIVE SETUP WILL COMMENCE FOR LATE THURSDAY
INTO THURSDAY NIGHT. A FRONTAL BOUNDARY WILL BE STALLED OUT OVER
NORTHEASTERN COLORADO AND NWRN KS. WITH HEATING AND THE ARRIVAL OF AN
UPPER LEVEL SHORTWAVE...THUNDERSTORMS WILL INITIATE DURING THE LATE
AFTERNOON HRS INVOF THE FRONT. THERE ARE SOME MODEL DIFFERENCES IN
THE LOCATION OF THE FRONTAL BOUNDARY THURSDAY AFTERNOON WITH THE NAM
SOLN BEING THE FARTHEST SOUTH. WITH MCS DEVELOPMENT PROBABLE
TOMORROW NIGHT...JUST WHERE THIS BOUNDARY WILL LIE DOWN THURSDAY
WILL BE HARD TO PINPOINT...AS WILL BE THE SEVERE THREAT.
HOWEVER...ANOTHER ROUND OF SCATTERED THUNDERSTORMS IS POSSIBLE
THURSDAY NIGHT AS ACTIVITY ALONG THE FRONT LIFTS NORTH INTO THE
FORECAST AREA. FAVORABLE CONDITIONS...BOTH ALOFT AND AT THE SURFACE
FOR PRECIPITATION...WILL CONTINUE INTO FRIDAY. PERSISTENT SWRLY FLOW
ALOFT...A FRONTAL BOUNDARY ACROSS SWRN NEBRASKA AND EASTERLY AND
SERLY WINDS IN THE BOUNDARY LAYER ARE EXPECTED FRIDAY INTO FRIDAY
NIGHT. THE THREAT FOR SEVERE STORMS FRIDAY AFTERNOON AND FRIDAY
NIGHT WILL HINGE ON THE LOCATION OF THE SURFACE FRONTAL
BOUNDARY...WHICH ATTM IS EXPECTED TO LIE EITHER OVER SWRN NEBRASKA
OR OFF TO THE SW IN NERN COLORADO AND NWRN KS. LIKE WEDNESDAY AND
THURSDAY...SCATTERED THUNDERSTORMS WILL LIFT NORTH AND
NORTHEAST...FROM THE FRONTAL BOUNDARY INTO WESTERN AND NORTH CENTRAL
NEBRASKA FRIDAY EVENING AND FRIDAY NIGHT AND CHANCE POPS WERE
CONTINUED.
FRIDAY NIGHT THROUGH TUESDAY...AN UPPER LEVEL TROUGH WILL PERSIST
ACROSS THE INTERMOUNTAIN WEST FRIDAY NIGHT THROUGH SUNDAY
NIGHT...BEFORE LIFTING ACROSS THE CENTRAL PLAINS ON MONDAY. THE
THREAT FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THE
WEEKEND...MAINLY DURING THE LATE AFTERNOON AND EVENING HOURS AS
ABUNDANT LOW LEVEL MOISTURE REMAINS IN PLACE ACROSS THE FORECAST
AREA. ON MONDAY AND MONDAY NIGHT...THE MAIN UPPER LEVEL LOW WILL
LIFT NORTHEAST INTO THE CENTRAL PLAINS...TRACKING INTO THE LOWER
MISSOURI VALLEY ON TUESDAY. PRECIPITATION CHANCES WILL CONTINUE INTO
MONDAY...WITH DRIER CONDS EXPECTED MONDAY NIGHT INTO TUESDAY. HIGHS
WILL GENERALLY BE IN THE 70S...WITH 80S POSSIBLE NEXT
TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1245 PM CDT TUE MAY 20 2014
CONVECTIVE DEBRIS IN THE FORM OF AC COVERING THE MIDDLE OF THE
FORECAST AREA DUE TO SOME WEAK FGEN IN THE MIDDLE ATMOSPHERE
TAPPING SOME ELEVATED INSTABILITY. ECHOES ON RADAR HAVE GRADUALLY
WEAKENED AND MODELS CONTINUE THE TREND OF WEAKENING THE FGEN AND
MOVING IT NORTHWARD.
UPSLOPE FLOW CONTINUES IN THE PANHANDLE THOUGH DEW POINTS ARE ONLY
MODEST. STILL SHOULD BE ENOUGH TO GENERATE CONVECTION IN THE
HIGHER TERRAIN IN WY BY LATE AFTERNOON AND MOVE SOUTHEAST INTO
THE WESTERN FORECAST AREA. WITH NO SIGNIFICANT LARGE SCALE FORCING
INITIALLY...COVERAGE WILL BE LIMITED AND HAVE THEREFORE KEPT KLBF
AND KVTN DRY FOR OVERNIGHT. WILL HAVE TO WATCH POTENTIAL FOR
STRATUS WHICH WILL FAVOR THE PANHANDLE AREA ALONG AND EAST OF THE
RESDIUAL BOUNDARY. THIS MAY COME INTO THE SOUTHWEST WED MORNING
BUT BELIEVE IT WILL FAR ENOUGH WEST OF KLBF TO NOT INCLUDE A CIG
AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1216 PM CDT TUE MAY 20 2014
.UPDATE...
ISSUED AT 947 AM CDT TUE MAY 20 2014
VERY WEAK FRONT HAS SETTLED ALONG INTERSTATE 80 AND WILL CONTINUE
TO DRIFT SLOWLY SOUTH THROUGH THE REMAINDER OF THE DAY. 12Z UPPER
AIR ANALYSIS REVEALED 20 TO 40 METER HEIGHT RISES ACROSS THE
PLAINS...WITH AN 300 MB JET WELL NORTH OF THE AREA ACROSS THE
NORTHERN PLAINS INTO THE WESTERN GREAT LAKES REGION. 700MB TEMPS
SOUTH OF THE BOUNDARY WERE ALSO QUITE WARM FROM +12 TO +14.
ENTRANCE REGION OF THE UPPER JET MAY HELP TO IGNITE THUNDERSTORMS
NORTH OF THE BOUNDARY...BUT MAINLY ACROSS IOWA TODAY...BUT THEY
COULD ALSO DEVELOP AS FAR WEST AS THE OMAHA AREA BY 20-21Z...BUT
WILL ALSO BE FIGHTING A CAP. NOT SURE THEY COULD BACKBUILD FAR
ENOUGH TO THE LINCOLN AREA...THUS HAVE REMOVED THE SLIGHT CHANCE
POPS THAT FAR SOUTHWEST.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
WV IMAGERY THIS MORNING SHOWING POS TILT LONGWAVE TROF EXTENDING
FROM CNTRL CANADA TO THE WEST COAST WITH TWO DISTINCT CLOSED
CIRCULATIONS SEEN...ONE CENTERED OVER S-CNTRL CANADA AND THE OTHER
OF THE NRN CA COASTLINE. SATL PIX ALSO REVEALING MOVEMENT MOVEMENT OF
THIS FEATURE HAS BEEN MINIMAL THE LAST SEVERAL HOURS....BUT MODELS
IN GOOD AGREEMENT WEST COAST CIRCULATION WILL GRADUALLY BECOME CUT
OFF FROM MAIN FLOW BY THE TIME IT REACHES THE SWRN CONUS LATER THIS
WEEK.
MEANWHILE...DISTINCT SFC THERMAL BNDRY WAS SITUATED FROM NRN IA TO S-
CNTRL NEB TO WRN KS WITH LLVL MOISTURE ADV SPREADING NWD THRU OK/KS
AND INTO THE SRN CWA. OUT WEST...SMALL AREA OF ELEVATED CONVECTION
WAS SITUATED WITHIN AREA OF 700MB QG FRONTOGENESIS/MODEST BNDRY LYR
CONVG. LATEST HRRR IS SUGGESTING ACTIVITY WILL BE SHORT LIVED AS
ENVIRONMENT BECOMES MORE STABLE IN THE NEXT COUPLE COUPLE HOURS.
LATEST MODELS CONFIRM GOING FCST IS IN PRETTY GOOD SHAPE ADVERTISING
CONVECTIVE ACTIVITY LATER THIS WEEK...PARTICULARLY OVER WESTERN
SECTIONS OF THE CWA. AS AFOREMENTIONED UPPER LOW BECOMES CUT
OFF...FLOW ALOFT OVER THE CNTRL PLAINS WILL BECOME LESS PROGRESSIVE
AND ALLOW MID LYR FRONTOGENETIC FORCING ORIENTED NW-SE TO REMAIN
INVOF THE WRN CWA. THAT ALONG WITH RELATIVELY STRONG BNDRY LYR THETA-
E CONVG SHOULD ALLOW FOR TSTMS CHANCES BEGINNING LATE WED AFTN ALL
THE WAY INTO LATE THURSDAY NIGHT. AMPLE ENVIRONMENTAL MOISTURE WILL
BE ON TAP...PWS 1.75"/KI 35-40...THUS POTENTIAL FOR GENEROUS
RAINFALL AMOUNTS APPEAR TO BE RELATIVELY HIGH.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 301 AM CDT TUE MAY 20 2014
MODELS CONTINUE TO ADVERTISE WRN CIRCULATION WILL BE QUITE SO
MIGRATING EWD THRU THE EXTENDED PDS..ALLOWING FOR CONTINUOUS SLY
LLVL MOIST ADV INTO THE CNTRL PLAINS. WITH INSTABILITY/MOISTURE AXIS
REMAINING INVOF THE CWA...WILL CARRY POPS THRU NEXT WEEKEND AND INTO
EARLY NEXT WEEK. IN ADDITION...COMPOSITE PARAMETERS SUGGEST SVR
THREAT IS MINIMAL AT BEST.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1213 PM CDT TUE MAY 20 2014
VFR CONDITIONS THROUGH THE PERIOD. BROKEN DECK OF MID CLOUDS AT
6000-8000 FEET AT KOMA/KLNK...BUT SHOULD SCATTER OUT BY 21/01Z.
NORTHEAST WINDS AT 12 TO 18 KNOTS THROUGH THE REMAINDER OF THE
AFTERNOON AS WELL. COULD BE CONVECTION THAT DEVELOPS NEAR OMAHA
21-24Z...BUT NOT CONFIDENT ENOUGH THAT IT WOULD BE AT THAT TAF
LOCATION...THUS LEFT OUT FOR NOW...BUT WOULD AMEND FORECAST IF
STORMS MATERIALIZE AND WOULD DIRECTLY IMPACT THE SITE. WINDS LESS
THAN 07 KNOTS AFTER 01Z...BUT THEN INCREASE AGAIN TO 12 KNOTS OR
GREATER BY 21/15Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...DEWALD
SHORT TERM...DEE
LONG TERM...DEE
AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
302 PM CDT TUE MAY 20 2014
.SHORT TERM...
.REST OF THIS AFTERNOON AND TONIGHT - CONFIDENCE...MEDIUM
SPC MESO PAGE SHOWS PLENTY OF FAVORABLE PARAMETERS FOR THE SRN CWA.
MID LEVEL CAP SUPPRESSING THINGS A BIT BUT THIS IS PROGGD TO ERODE
WITH TIME. LOW LEVEL FLOW IS WEAK RESULTING IN UNFAVORABLE
0-1KM SHEAR. CONVERGENCE IS WEAK. MID LEVEL CAP IS A SUPPRESSING
FORCE. 850 LOW LEVEL JET IS WELL SOUTH AND NO DISCERNIBLE
SHORTWAVE UPSTREAM IN WATER VAPOR. ON THE PLUS SIDE 0-6KM SHEAR IS
INCREASING INTO SC WI AT 40-50 KNOTS. CRAVEN/BROOKS SHOWS 50,000
INTO SC WI. AGAIN..NOT MUCH ORGANIZATION IN THE LOW LEVELS WITH
WEAK FLOW AND BAGGY PRESSURE GRADIENT. MID LEVEL SPEED MAX AND
DIVERGENCE ASSOCIATED WITH THIS COMBINED WITH APPCH FRONTAL
FORCING WILL LIKELY GET THINGS GOING. HRRR/NAM/GFS ALL POTENTIAL
FOR MOST ORGANIZED DEVELOPMENT BETWEEN 00-06Z IN THE SRN TWO TIERS
WITH THE 4KM SPC WRF SHOWING ONLY ISOLATED DEVELOPMENT IN THE FAR
SOUTH WITH CONVECTION STAYING LARGELY TO OUR SOUTH. BULK OF DATA
SUPPORTS AT LEAST SOME ACTIVITY ALONG AND SOUTH OF I-94 THIS
AFTN/EVENING. IF THE STORMS GET GOING THEN LARGE HAIL LOOKS LIKE
THE MOST FAVORABLE THREAT DUE TO THE MID LEVEL LAPSE RATES AND
PLENTIFUL CAPE IN THE -10 TO -30C RANGE. SIGNIFICANT HAIL
PARAMETER HAS INCREASED MARKEDLY INTO SC WI THIS AFTN WITH MID
LEVEL LAPSE RATES OF AT LEAST 7.5C. CIPS ANALOGS ALSO HAS HIGHER
HAIL PROBABILITIES INTO SC WI AS WELL. DOWNDRAFT CAPE PUSHING 1000
NEAR THE BORDER SO SOME WIND THREAT THERE AS WELL. WILL HAVE
HIGHEST POPS THIS EVENING IN THE SRN CWA AND TRAIL THINGS OFF IN
THE NORTH. EXPECT ANY LINGERING CONVECTION TO QUICKLY EXIT THE
SOUTHEAST BY MIDNIGHT OR SHORTLY THEREAFTER.
.WEDNESDAY - CONFIDENCE...MEDIUM
BROADLY CYCLONIC FLOW WITH BEST VORT ACTION WITHIN THIS FLOW WELL
NORTH AND NORTHEAST OF THE CWA. 850 COLD ADVECTION GRADUALLY
COMMENCES ...THOUGH ONLY SUBTLE COOLING AT 925 NOTED AFTER 18Z.
SO WILL FORECAST TOASTY TEMPS WELL INTO THE 70S WITH SOME AREAS AT
OR SLIGHTLY ABOVE 80 WITH PREDOMINANTLY WNW FLOW.
.WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE HIGH.
A SHORTWAVE MOVES ACROSS SOUTHEAST CANADA JUST NORTH OF THE LAKE
SUPERIOR AND LAKE HURON AREA...WITH THE MID/UPPER LEVEL FLOW
MORE NORTHWEST ACROSS WISCONSIN. THE SPEED MAX INCREASES TO 105
KNOTS ACROSS CENTRAL AND SOUTHEAST WISCONSIN THURSDAY. 700 MB RH
DRIES WEDNESDAY NIGHT. 700/850 MB COLD AIR ADVECTION CONTINUES
WEDNESDAY NIGHT...THEN BEGINS TO RISE A LITTLE AT 850 MB LATER
THURSDAY. 850 MB RH INCREASES DURING THE DAY THURSDAY...SO SOME
FAIR WEATHER CUMULUS EXPECTED. FORECAST SOUNDINGS SHOW MOISTURE
IS CONFINED TO THE 850 MB LAYER JUST BELOW THE STRONG INVERSION.
THE SURFACE HIGH PRESSURE BUILDS INTO THE UPPER MISSISSIPPI
VALLEY AND WISCONSIN AREA THURSDAY. THE LIGHT NORTHWEST WINDS ARE
EXPECTED TO BECOME NORTHEAST OVER SOUTHEAST WISCONSIN...WITH LAKE
MICHIGAN COOLING DURING THE AFTERNOON.
.THURSDAY NIGHT AND FRIDAY....FORECAST CONFIDENCE HIGH.
THE MID/UPPER LEVEL FLOW CONTINUES FROM THE NORTHWEST WITH A
STRONG RIDGE BUILDING OVER THE EASTERN DAKOTAS AND WESTERN
MINNESOTA. NAM FORECAST SOUNDINGS CONTINUE TO SHOW A SHALLOW
MOISTURE LAYER AT 850 MB. NOT THICK ENOUGH FOR ANYTHING MORE THAN
MAINLY SCATTERED AFTERNOON FAIR WEATHER CUMULUS.
THE SURFACE HIGH EXTENDS ACROSS WISCONSIN AND THE WESTERN GREAT
LAKES WITH A LIGHT NORTHEAST FLOW ACROSS SOUTHERN WISCONSIN.
.LONG TERM...
.SATURDAY AND SUNDAY...FORECAST CONFIDENCE MEDIUM.
THE MID/UPPER LEVEL RIDGE REMAINS NEAR THE UPPER MISSISSIPPI
VALLEY SATURDAY AND OVER WISCONSIN SATURDAY...BEFORE MOVING INTO
LOWER MICHIGAN SUNDAY.
THE SURFACE HIGH BECOMES CENTERED OVER THE GREAT LAKES AND UPPER
OHIO VALLEY SATURDAY AND OVER THE EASTERN GREAT LAKES AND
NORTHEAST U.S. SUNDAY. THIS BEGINS A SOUTH FLOW OF WARMER AIR. THE
12Z GFS AND 06Z DGEX SPREADS SOME LIGHT PRECIPITATION INTO
SOUTHERN WISCONSIN SUNDAY EXCEPT FOR THE FAR EAST...BUT THE 00Z
ECMWF REMAINS DRY EXCEPT FOR THE FAR WEST SUNDAY AFTERNOON AND IS
PREFERRED.
.MONDAY AND TUESDAY...FORECAST CONFIDENCE MEDIUM.
THE MID/UPPER RIDGE REMAINS FROM THE SOUTHEAST U.S. TO THE EASTERN
GREAT LAKES WITH A TROUGH AND WEAK CUT OFF LOW OVER THE CENTRAL
PLAINS. THE GFS AND ECMWF ARE IN VERY GOOD AGREEMENT EVEN AT
DAY 7.
THE GFS/ECMWF AND DGEX ALL BRING PRECIPITATION LATER SUNDAY NIGHT
AND MONDAY AND CONTINUES IT ON TUESDAY AS THE SOUTH FLOW CONTINUES
WITH LOW PRESSURE OVER THE PLAINS.
&&
.AVIATION/00Z TAFS/...
MAIN CONCERN WILL BE CONVECTIVE TRENDS THIS
AFTN/EVE. ML CAPES HAVE REACHED 2000 PLUS. EXPECTING CONVECTION TO
BUBBLE UP FROM MID AFTERNOON INTO EARLY EVENING. PER SWODY1...AREAS
ALONG AND SOUTH OF I-94 ARE MORE UNDER THE GUN. LARGE CAPE VALUES IN
THE -10 TO -30C SO CONCERN FOR LARGE HAIL DEVELOPMENT. HRRR SHOWS
SCT CELLS DVLPG 22-00Z ACRS SRN WI WITH MORE ORGANIZED CONVECTION
BRUSHING THE FAR SOUTH AFTER EVENING DEVELOPMENT IN ERN IA. 850 COLD
ADVECTION INCREASES ON WEDNESDAY WITH CONVECTIVE FOCUS SHIFTING INTO
THE OH VLY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...COLLAR
WEDNESDAY NIGHT THROUGH TUESDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
259 PM CDT TUE MAY 20 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 258 PM CDT TUE MAY 20 2014
LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL RIDGE
FLATTENING OUT OVER THE UPPER MIDWEST AND GREAT LAKES REGION. A VERY
WEAK SHORTWAVE TROUGH ON THE NORTHERN PERIPHERY OF THE UPPER LEVEL
RIDGE IS PRODUCING VERY LIGHT RAIN OR SPRINKLES ACROSS SOUTHERN
MINNESOTA PER LATEST MOSAIC RADAR. LATEST 19Z SURFACE ANALYSIS
INDICATING A WEAK COLD FRONT EXTENDING FROM CENTRAL WISCONSIN INTO
CENTRAL IOWA.
MAIN FORECAST CONCERNS ARE SHOWERS AND THUNDERSTORMS DEVELOPMENT
ALONG SURFACE FRONT LATE THIS AFTERNOON AND THIS EVENING. THE LATEST
20.12Z GFS/NAM AND 20.15Z RAP ARE INDICATING ALONG SURFACE FRONT CAP
WILL BREAK IN THE 22Z TUESDAY - 02Z WEDNESDAY TIME FRAME AND FOR
SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG SURFACE FRONT PER BUFKIT
SOUNDINGS OVER EXTREME SOUTHERN FORECAST AREA. THE LATEST 20.16Z
HRRR DEVELOPS SHOWERS AND THUNDERSTORMS AROUND 23Z ACROSS SOUTHERN
FAYETTE...CLAYTON AND GRANT COUNTIES. THE 20.15Z RAP AND 20.12Z NAM
INDICATES ROUGHLY 1000-2000 J/KG OF SURFACE BASE CAPE AND 0-6KM
SHEAR APROACHING 40 KNOTS LATE THIS AFTERNOON ALONG AND AHEAD
SURFACE FRONT ACROSS THE EXTREME SOUTHERN FORECAST AREA. THE 20.15Z
RAP/20.12Z NAM SHOW 0-1KM SHEAR LESS THAN 5 KNOTS OVER THIS AREA.
THE EXTREME SOUTHERN FORECAST AREA POSSIBLY COULD SEE SEVERE
THUNDERSTORMS WITH THE MAIN THREATS AT THIS TIME LOOK TO BE LARGE
HAIL AND WIND OVER THE EXTREME SOUTHERN FORECAST AREA.
SURFACE FRONT MOVES SOUTH OF FORECAST AREA WEDNESDAY AND DRIER AIR
AND SLIGHTLY COOLER AIR FILTERS INTO THE FORECAST AREA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 PM CDT TUE MAY 20 2014
SURFACE RIDGE BUILDS INTO THE FORECAST AREA THURSDAY INTO FRIDAY.
WITH SUBSIDENCE UNDERNEATH RIDGE AND FORECAST AREA UNDER NORTHERLY
FLOW. THIS SHOULD ALLOW FOR DRY WEATHER CONDITIONS AND SEASONABLE
TEMPERATURES ACROSS THE FORECAST AREA.
FOCUS THEN TURNS TO FRIDAY NIGHT INTO TUESDAY...WHERE THE MAIN
CONCERNS ARE PRECIPITATION CHANCES SATURDAY NIGHT INTO TUESDAY. THE
20.12Z GFS/ECMWF/GEM ARE IN GOOD AGREEMENT IN BUILDING UPPER
LEVEL RIDGE INTO THE CENTRAL UNITED STATES THIS WEEKEND...THEN
BREAKING DOWN UPPER LEVEL RIDGE AND DEVELOP SOUTHWEST FLOW OVER
THE CENTRAL UNITED STATES BY 00Z MONDAY. THE BIGGEST DIFFERENCES
BETWEEN THE MODELS IS TIMING AND STRENGTH OF SHORTWAVE TROUGHS
EJECTING OUT INTO THE NORTHERN PLAINS AND UPPER GREAT LAKES REGION
THROUGH THE PERIOD. THE FORECAST AREA SHOULD REMAIN DRY THROUGH
SATURDAY NIGHT AS UPPER LEVEL RIDGE DOMINATES THE GREAT LAKES
REGION. THEN...FIRST IMPULSE BEGINS TO BREAK RIDGE DOWN SUNDAY AND
PROVIDE THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS INTO THE
WESTERN HALF OF THE FORECAST AREA. WITH UPPER LEVEL RIDGE BREAKING
DOWN OVER THE UPPER MIDWEST AND GREAT LAKES REGION MEMORIAL DAY
AND TUESDAY...A SERIES OF SHORTWAVE TROUGHS EMBEDDED IN THE
SOUTHWESTERLY FLOW ALOFT WILL MOVE OVER THE AREA. THE 20.12Z
GFS/ECMWF/GEM INDICATE STRENGTH ISSUES WITH EACH SHORTWAVE
TROUGH...HOWEVER THE SHORTWAVE TROUGH SHOW BETTER MOISTURE
TRANSPORT/CONVERGENCE OVER THE REGION BY 00Z TUESDAY. WILL
CONTINUE WITH CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS FORECAST
AREA...ESPECIALLY LATE MEMORIAL DAY INTO TUESDAY. TEMPERATURES
FRIDAY NIGHT INTO TUESDAY WILL BE SLIGHTLY ABOVE NORMAL...AS THE
GFS/ECMWF/GEM INDICATE 850MB TEMPERATURES IN THE PLUS 14 TO PLUS
16 DEGREES CELSIUS RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1235 PM CDT TUE MAY 20 2014
A SHORT WAVE TROUGH MOVING OUT OF THE DAKOTAS WILL PRODUCE A
10-15K DECK OF CLOUDS AT THE TAF SITES THROUGH 21.09Z. THERE MAY
BE EVEN SOME SCATTERED SPRINKLES NORTH OF INTERSTATE 90. AFTER
20.21Z...EXPECT A BAND OF THUNDERSTORMS TO DEVELOP ACROSS FAYETTE
AND CLAYTON COUNTIES IN NORTHEAST IOWA AND GRANT COUNTY IN
SOUTHWEST WISCONSIN. THESE THUNDERSTORMS ARE EXPECTED TO MOVE
SOUTH OF THESE COUNTIES BY 21.06Z. WINDS ACROSS THE AREA ARE
EXPECTED TO LIGHT AND VARIABLE THROUGH 21.15Z...AND THEN BECOME
NORTHWEST AND CLIMB INTO THE 5 TO 15 KNOT RANGE.
&&
.HYDROLOGY...
ISSUED AT 258 PM CDT TUE MAY 20 2014
WATER LEVELS CONTINUE TO SLOWLY FALL ALONG THE MISSISSIPPI RIVER AND
FEW LOCATIONS REMAIN ABOVE FLOOD STAGE. THE WATER LEVELS WILL REMAIN
HIGH ALONG THE MISSISSIPPI RIVER THROUGH NEXT WEEK.
IN ADDITION...DUE TO RECENT RAINFALL AMOUNTS OF ONE TO TWO AND A
HALF INCHES IN THE HEADWATERS OF THE BLACK RIVER. THE BLACK RIVER
HAS RISEN ABOVE FLOOD OR IS EXPECTED TO RISE ABOVE FLOOD STAGE AT A
COUPLE LOCATIONS OVER THE NEXT COUPLE OF DAYS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...BOYNE
HYDROLOGY...DTJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1138 AM CDT TUE MAY 20 2014
.AVIATION/18Z TAFS/...AXIS OF MOISTURE CONVERGENCE EXTENDS FROM SC
WI INTO ERN IA. ML CAPE VALUES HAVE ALREADY REACHED 1000 J/KG AND
WILL CONTINUE TO PUSH FOR 2000 INTO SC WI AS THE AFTERNOON WEARS
ON WITH MOSTLY CLEAR SKIES IN PLACE. EXPECTING CONVECTION TO
BUBBLE UP FROM MID AFTERNOON INTO EARLY EVENING. PER
SWODY1...AREAS ALONG AND SOUTH OF I-94 ARE MORE UNDER THE GUN.
LARGE CAPE VALUES IN THE -10 TO -30C SO CONCERN FOR LARGE HAIL
DEVELOPMENT. HRRR SHOWS SCT CELLS DVLPG 22-00Z ACRS SRN WI WITH
MORE ORGANIZED CONVECTION BRUSHING THE FAR SOUTH AFTER EVENING
DEVELOPMENT IN ERN IA. 850 COLD ADVECTION INCREASES ON WEDNESDAY
WITH CONVECTIVE FOCUS SHIFTING INTO THE OH VLY.
PC
&&
.PREV DISCUSSION... /ISSUED 326 AM CDT TUE MAY 20 2014/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
STRONG SURGE OF WARM AIR AND MOISTURE ADVECTION CONTINUING TO
ADVANCE TO THE NORTHEAST OF CWA EARLY THIS MRNG. SHORT WAVE
RIDGING AND DRIER AIR ABOVE THE SURFACE REDUCING ALREADY SMALL
THREAT FOR FURTHER CONVECTION THIS MRNG...SO TRIMMED BACK POPS IN
THE NORTHEAST AFT 12Z.
HOWEVER LOW LEVEL CONVERGENCE AND INCREASING SFC MOISTURE
CONTRIBUTING TO EXPANDING STRATUS FIELD BEHIND DEPARTING -SHRA
OVER CWA. EXPECT STRATUS TO STICK AROUND WHILE WARM FRONT SHIFTS
TO THE NORTH FOR A TIME THIS MRNG BEFORE THINNING AND BREAKING UP
LATER THIS MRNG AND AFTN. WINDS WL TURN MORE TO THE SOUTH AS WMFNT
SETTLES OVER CENTRAL WI. FORTUNATELY...ISOLD CONVECTION OVER
CENTRAL IA WEAKENING AS LOW LEVEL JET WEAKENS AND PIVOTS TO THE
EAST.
WITH SFC DEWPTS EXPCD TO RISE INTO THE UPPER 50S TO LOWER 60S IN
WARM SECTOR THIS AFTN...SFC BASED CAPE VALUES MAY RISE TO ABV 2K
J/KG WITH STRONG 0-6KM SHEAR. STRONGEST RETURN OF MOISTURE FLUX
CONVERGENCE RETURNS TO NRN IL THIS AFTN...BUT DOES CLIP SRN WI
INTO THE EVE. DESPITE WEAK FRONTAL BOUNDARY MOVING THRU SRN WI
DURING THE AFTN/EVE...POTENTIAL FOR ROTATING UPDRAFTS AND LARGE
HAIL AFT 21Z.
EXPC SCT CONVECTION TO INCREASE AND BECOME MORE LINEAR AS IT
SETTLES INTO NRN IL DURING THE EARLY EVE WITH DIMINISHING THREAT
FOR CONVECTION. SPC STORM-SCALE ENSEMBLE OF OPPORTUNITY HAS A HIGH
LIKELIHOOD FOR REFL ABOVE 40DBZ BY 00Z/21 OVER SRN TIER OF
COUNTIES BUT STRONGEST UPDRAFT HELICITY AND SPEED REMAINS FARTHER
TO THE SOUTH EARLY THIS EVE. BRIEF HEAVY RAINS WL ACCOMPANY
CONVECTION DUE TO HIGH PWAT VALUES.
SHORT TERM...WEDNESDAY THROUGH THURSDAY NIGHT...FORECAST
CONFIDENCE IS HIGH.
MODELS SHIFT COLD FRONT EAST OF THE AREA WEDNESDAY MORNING...WITH
COLD AIR ADVECTION IN ITS WAKE WEDNESDAY AFTERNOON AND NIGHT. 500
MB FLOW REMAINS WEST NORTHWEST DURING THIS TIME. AFTER ANOTHER
WARM DAY WEDNESDAY...SLIGHTLY COOLER TEMPERATURES SHOULD MOVE IN
BY WEDNESDAY NIGHT. DRIER AIR WILL ALSO MOVE IN...AND LOWER DEW
POINTS. BREEZY NORTHWEST WINDS WEDNESDAY SHOULD MAINTAIN HIGHS IN
THE MID TO UPPER 70S IN MOST AREAS...SIMILAR TO BLENDED MODEL
GUIDANCE.
HIGH PRESSURE THEN SLOWLY MOVES EASTWARD INTO THE REGION THURSDAY
AND THURSDAY NIGHT...AS 500 MB FLOW REMAINS NORTHWESTERLY WITH A
RIDGE BUILDING IN THE NORTHERN PLAINS. DRY AIRMASS WILL REMAIN IN
PLACE...AND WILL CONTINUE TO BRING QUIET WEATHER. WINDS WILL SHIFT
ONSHORE THURSDAY AFTERNOON...KEEPING HIGHS THERE IN THE LOWER 60S.
MID 60S TO AROUND 70 ARE FORECAST INLAND...SIMILAR TO 925 MB
TEMPERATURES AND BLENDED MODEL GUIDANCE.
LONG TERM...FRIDAY THROUGH MEMORIAL DAY...FORECAST CONFIDENCE IS
MEDIUM.
GFS/ECMWF SHOW FAIRLY SIMILAR TRENDS FRIDAY INTO SUNDAY...THEN
DIFFER SOMEWHAT AFTERWARDS. THEY BRING THE 500 MB RIDGE EASTWARD
ACROSS THE REGION FRIDAY INTO SATURDAY NIGHT. HIGH PRESSURE AT
THE SURFACE SLOWLY MOVES EAST ACROSS THE REGION FRIDAY INTO
SATURDAY...THEN TO THE EAST SATURDAY NIGHT.
THE HIGH WILL CONTINUE TO PROVIDE QUIET WEATHER FRIDAY INTO
SATURDAY NIGHT...WITH A DRY AIRMASS IN PLACE. WARM DAYS IN THE 70S
ARE EXPECTED INLAND...WITH ONSHORE WINDS KEEPING 60S NEAR THE
LAKE. LOWS WILL RISE EACH NIGHT...AS GRADUAL WARM AIR ADVECTION
OCCURS.
THE 500 MB RIDGE CONTINUES TO MOVE EAST SUNDAY INTO MEMORIAL
DAY...WITH WARM AIR ADVECTION DEVELOPING OVER THE REGION. MOISTURE
MOVES BACK INTO THE AREA DURING THIS TIME...WITH FORECAST
SOUNDINGS SHOWING SOME MEAN LAYER CAPE DEVELOPING. SOME
DIFFERENCES WITH THE MODELS IN AREAL COVERAGE OF QPF...THOUGH THEY
INDICATE BEST SHOT WILL BE NORTH AND WEST OF THE AREA.
GRADUALLY BROUGHT THUNDERSTORM CHANCES BACK INTO THE AREA DURING
THIS PERIOD. TEMPERATURES SHOULD CONTINUE TO BE WARM ACROSS THE
AREA...ESPECIALLY BY MEMORIAL DAY WITH SOUTHWEST WINDS.
AVIATION/12Z TAFS/...
LOW LEVEL CONVERGENCE AND INCREASING LOW LEVEL HUMIDITY ALONG
APPROACHING WARM FRONT RESULTING IN EXPANDING MVFR CIGS OVER
NORTHERN CWA LAST SEVERAL HOURS. LOWER CIGS MAY EXPAND SWD THROUGH
EARLY THIS MRNG TO AFFECT TAF SITES FOR FEW HOURS.
OTRW...STILL EXPECT WMFNT TO PASS NWD INTO CENTRAL WI LATER THIS
MRNG AND AFTN SO PREDOMINANTLY VFR CIGS EXPECTED LATER IN TAF
PERIODS. APPROACHING WEAK FRONT AND AFTN INSTABILITY WL TRIGGER
SCT CONVECTION OVER SRN WI INTO THE EVE WHICH MAY BRIEFLY LOWER
CIGS AND VSBYS TO MVFR.
MARINE...
WILL CONTINUE SMALL CRAFT ADVY THROUGH THE MRNG DESPITE LAKESHORE
LOWER OBSERVATIONS WINDS AND GUSTS. PARKED SMALLER VESSELS IN
HARBOR AS WELL AS LARGER CARRIERS UNDERWAY IN OPEN WATERS
REPORTING SUSTAINED WINDS OF 15 TO 25 KNOTS. STILL EXPECT SOME
GUSTINESS TO OCCASIONALLY TO BREAK THROUGH LOW LEVEL TEMPERATURE
INVERSION TO SURFACE THIS MRNG. PRESSURE GRADIENT WEAKENS LATER
THIS MRNG AND AFTN AS WEAK FRONTAL BOUNDARY APPROACHES FROM THE
WEST.
LAKE MI SFC WATER TEMPS REMAIN IN THE LOW TO MID 40S. HIGHER SFC
DEWPTS IN THE 50S JUST UPSTREAM SHOULD MOVE ACROSS COOLER LAKE
WATER LATER TODAY INTO THIS EVENING. WL ADD FOG MENTION AND COULD
BE DENSE DUE TO LIGHTER LOW LEVEL WINDS LATER TODAY. WL MENTION IN
HWO.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
WEDNESDAY THROUGH MONDAY...WOOD
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
323 PM MDT TUE MAY 20 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 300 PM MDT TUE MAY 20 2014
FORECAST CHALLENGES CONTINUE TO BE SEVERE THUNDERSTORM CHANCES
TODAY AND WEDNESDAY.
CURRENTLY...FAIRLY QUIET RIGHT NOW EARLY THIS AFTERNOON ACROSS THE
CWFA. STARTING TO GET SOME LIGHTNING STRIKES FROM CONVECTION
DEVELOPING OVER THE LARAMIE RANGE. WOULD EXPECT THIS TO CONTINUE
TO INCREASE IN COVERAGE AND INTENSITY AS THE AFTERNOON CONTINUES.
EASTERLY TO SOUTHEASTERLY SURFACE WINDS ACROSS EASTERN PORTIONS OF
THE CWFA WITH PRETTY GOOD DEWPOINTS. GETTING UPPER 40S OUT BY
CHADRON...47 HERE AT CHEYENNE AND 43 UP BY DOUGLAS. TEMPERATURES
IN THE MID 60S JUST ABOUT EVERYWHERE EAST OF THE LARAMIE RANGE.
LATEST SPC MESOANALYSIS SHOWING SURFACE BASED CAPES AROUND 1000
J/KG ALONG THE LARAMIE RANGE WITH NO CONVECTIVE INHIBITION
ANALYZED AT THIS TIME. LIFTED INDICES NEAR ZERO JUST ABOUT
EVERYWHERE WITH -3C IN THE GENERAL LOCATION WHERE CONVECTION IS
INITIATING. LATEST WATER VAPOR IMAGERY SHOWING CLOSED LOW MOVING
INTO CENTRAL NEVADA THIS AFTERNOON.
FOR LATER THIS AFTERNOON...LOOKING AT LIFTED INDICES TO CONTINUE
FALLING TO -3 TO -4C ACROSS MUCH OF THE AREA EAST OF THE LARAMIE
RANGE BY 00Z. LATEST HRRR CONVECTIVE FORECAST KEYED INTO A
SUPERCELL DEVELOPING NEAR WHEATLAND THIS AFTERNOON...THEN TRACKING
EAST ACROSS TORRINGTON BY 23Z AND THEN INTO SOUTHERN SIOUX COUNTY
BY THE 00-01Z TIME FRAME. CONVECTION FAIRLY WIDESPREAD ACROSS THE
NORTHERN PANHANDLE AFTER 00Z. HIGH 0-6KM BULK SHEAR FORECASTS OF
60 TO 65KTS SHOULD SUPPORT VERY LARGE HAIL DEVELOPMENT WITH STORMS
THAT GET GOING THIS AFTERNOON. ONE LAST ITEM WITH THE STORMS
TODAY. FORECAST STORM MOTIONS ARE LOW...GENERALLY 10KTS OR LESS.
SO WE NEED TO WATCH FOR HEAVY RAIN/POSSIBLE LOCALIZED FLASH
FLOODING.
PRETTY MUCH A REPEAT FOR WEDNESDAY AFTERNOON. SEVERE THUNDERSTORM
POTENTIAL WILL CONTINUE FOR LOCATIONS EAST OF THE LARAMIE RANGE.
MAYBE MORE DOWN IN THE SOUTHERN PART OF THE CWFA DOWN HERE NEAR
CHEYENNE.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 300 PM MDT TUE MAY 20 2014
MEDIUM RANGE GUIDANCE IS IN EXCELLENT AGREEMENT WITH A POTENT CUTOFF
LOW OVER THE 4 CORNERS EARLY IN THE FCST PERIOD. NOT MUCH CHANGE IN
SENSIBLE WEATHER ACROSS THE REGION WITH THIS PATTERN IN PLACE...WITH
CONTINUED DAILY CHANCES FOR SHOWERS AND STORMS THROUGH THE WEEKEND
AND INTO EARLY NEXT WEEK. THIS FEATURE LIFTS NORTHEAST TOWARD THE
CENTRAL HIGH PLAINS ON SUN AND MON WITH THE ECMWF STILL ADVERTISING
DEFORMATION PRECIP BANDING ON THE BACK SIDE. POTENTIAL EXISTS FOR A
FAIRLY WIDESPREAD MODERATE RAIN EVENT DURING THIS TIME...HOWEVER THE
GFS IS NOT AS BULLISH WITH QPF AMOUNTS. WILL NEED TO WATCH CLOSELY
AS THIS WILL CAUSE HYDRO ISSUES IF THIS PCPN FALLS OVER THE SNOW
PACKED MOUNTAINS. H7 TEMPS WILL BE AROUND 8 TO 10 DEG C THROUGH THE
MAJORITY OF THE FCST PERIOD...GIVING WAY TO HIGHS BETWEEN 65 AND 75
DEGREES FOR MUCH OF THE LOWER ELEVATIONS. WESTERLY DOWNSLOPE RETURNS
ON MON...GIVING WAY TO WARMER AND DRIER CONDITIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1129 AM TUE MAY 20 2014
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON AND EVENING. INITIAL ACTIVITY
WILL BE OVER THE HIGHER TERRAIN OF SOUTHEAST WYOMING AFTER 20 UTC
BEFORE SPREADING INTO THE PANHANDLE LATER IN THE DAY. THESE STORMS
MAY PRODUCE LARGE HAIL AND GUSTY/ERRATIC WINDS...AS WELL AS BRIEF
MVFR CIGS OR VSBYS. WESTERN TERMINALS WILL SEE WIND GUSTS BETWEEN
25 AND 30 KTS THROUGH EARLY EVE OUTSIDE OF THUNDERSTORMS. MOIST
SOUTHEAST FLOW MAY RESULT IN LOW STRATUS AND MVFR CIGS BELOW 3000
FEET AGL AT KCYS AROUND 12-15 UTC WED.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT TUE MAY 20 2014
CONCERNS TO REMAIN LOW FOR THE REST OF THE WEEK WITH CONDITIONS
AND FUELS EXPECTED TO REMAIN NON-CRITICAL. SCATTERED AFTERNOON AND
EVENING THUNDERSTORMS WILL MOVE ACROSS MAINLY EASTERN DISTRICTS
MOST DAYS WITH VERY GOOD CHANCES FOR WETTING RAINS. A MORE
WIDESPREAD RAIN EVENT SATURDAY AFTERNOON THROUGH MONDAY MORNING
SHOULD DEVELOP ACROSS SOUTHEAST WYOMING AND NEBRASKA
PANHANDLE...SO FIRE WEATHER CONCERNS ARE MINIMAL.
&&
.HYDROLOGY...
ISSUED AT 300 PM MDT TUE MAY 20 2014
NORMAL TO ABOVE NORMAL TEMPERATURES TO CONTINUE FOR THE REMAINDER
OF THE WEEK FOR THE FORECAST AREA...ALONG WITH A CONTINUED WET
PATTERN. RISES ON TRIBUTARIES AND HEADWATERS ARE EXPECTED FOR THE
SNOWY AND SIERRA MADRE RANGES WITH THESE WARM TEMPERATURES. THE
LARAMIE RIVER...UPPER NORTH PLATTE AND LITTLE SNAKE RIVERS SHOULD
CONTINUE TO SEE SIGNIFICANT RISES THROUGH THE END OF THE WEEK.
RAIN CHANCES CONTINUE JUST ABOUT EVERY AFTERNOON AND EVENING
THROUGH THE WEEKEND. THE ECMWF FORECAST MODEL CONTINUES TO
FORECAST A WIDESPREAD MODERATE RAIN EVENT SATURDAY AFTERNOON
THROUGH MONDAY MORNING FOR AREAS WEST OF THE LARAMIE RANGE. THIS
IS DUE TO A SLOW MOVING LOW PRESSURE SYSTEM TRACKING ACROSS CENTRAL
COLORADO. FREEZING LEVELS LOOK TO STAY ABOVE 10K FEET THROUGH THIS
EVENT. SO RAPID SNOW MELT AND SIGNIFICANT FLOODING/RIVER RISES
COULD TAKE PLACE. WILL CONTINUE TO MONITOR AND ISSUE ANY WATCHES
AS THE EVENT DRAWS CLOSER.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...HAMMER
AVIATION...HAMMER
FIRE WEATHER...CLAYCOMB
HYDROLOGY...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1142 AM MDT TUE MAY 20 2014
.UPDATE...
ISSUED AT 1129 AM MDT TUE MAY 20 2014
LATEST SPC OUTLOOK AND HRRR CONVECTIVE FORECAST SHOWING SEVERE
CONVECTIVE POTENTIAL FROM SOUTHERN CONVERSE COUNTY ALL THE WAY
DOWN TO CHEYENNE AND SIDNEY. WENT AHEAD AND EXTENDED THE SEVERE
THUNDERSTORMS IN THE FORECAST FURTHER NORTH. UPDATES HAVE BEEN
SENT.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 333 AM MDT TUE MAY 20 2014
NO SIGNIFICANT CHANGE SEEN IN THE OVERALL WEATHER PATTERN ACROSS
THE CWA THROUGH THURSDAY AS THE AREA WILL REMAIN UNDER A GENERALLY
SW TO SOUTHERLY UPPER FLOW AHEAD OF AN UPPER LOW THAT WILL MOVE
OVER THE FAR SW CONUS TODAY THEN MEANDER AROUND THAT AREA THROUGH
THURSDAY. SEVERAL IMPULSES OF ENERGY WILL LIFT NORTHEAST FROM THE
UPPER LOW AND ACROSS THE REGION AND THESE WILL COMBINE WITH DECENT
INSTABILITY AND MODEST UPSLOPE FLOW TO PRODUCE SCATTERED SHOWERS
AND TSTMS OVER MOST OF THE CWA TODAY THROUGH THURSDAY. AS HAS BEEN
THE CASE THE PAST COUPLE OF DAYS SUFFICIENT SHEAR AND INSTABILITY
SHOULD EXIST FOR A FEW STRONG TO SEVERE STORMS TODAY AND
WEDNESDAY...MAINLY OVER THE SOUTHERN PANHANDLE INTO EXTREME SE WY
WITH HAIL THE MAIN SEVERE WEATHER FORM. BETTER INSTABILITY LOOKS
LIKE IT WILL SHIFT FARTHER SOUTHWARD FOR THURSDAY THUS SEVERE
THREAT SHOULD BE LOWER THEN.
TEMPERATURES A BIT COOLER TODAY BEHIND A MODEST PACIFIC FRONT
WITH LITTLE CHANGE IN TEMPERATURES SEEN FOR WEDS AND THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MEMORIAL DAY)
ISSUED AT 333 AM MDT TUE MAY 20 2014
UPPER-LOW NR THE BAJA OF CALIFORNIA WILL SLOWLY BEGIN TO LIFT
NORTHEAST ACROSS ARIZONA ON FRIDAY...THROUGH NEW MEXICO
SATURDAY...REACHING SOMEWHERE NR SE COLORADO OR THE TX PANHANDLE
BY SUNDAY. ECMWF/GFS ADVERTISE A SHORTWAVE WILL EJECT SOUTH-TO-
NORTH FROM THE PARENT UPPER-LOW ON FRIDAY. THE BL WILL CONTINUE TO
BE VERY MOIST AS SOUTHEASTERLY FLOW MAINTAINS 50-60F DEW POINTS.
PROGD PWATS OF AROUND 0.75 INCH ALONG THE FRONT RANGE WOULD PLACE
IT ABOVE THE 75 PERCENTILE OF CLIMATOLOGICAL VALUES. SLOW STEERING
FLOW AND RESULTANT POOR SHEAR PARAMETERS POINTS TO LIMITED SEVERE
WEATHER THREAT AND EFFICIENT HEAVY RAIN PRODUCERS. HAVE BOOSTED
THUNDERSTORM CHANCES INTO THE LIKELY CATEGORY OVR THE SOUTHEAST WY
PLAINS AND SRN NEBRASKA PANHANDLE FRIDAY.
MUCH OF THE SAME IS IN STORE FOR SATURDAY MINUS THE DISCERNABLE
SHORTWAVE...AS THE UPPER-LOW WOBBLES TOWARDS NRN NEW MEXICO.
DIFFLUENT SOUTHEAST FLOW IN THE MID-LEVELS COMBINED WITH PROGD
CAPES IN THE VICINITY OF 1000 J/KG WILL RESULT IN ISOLATED TO
SCATTERED CONVECTION. LIGHTER WINDS WILL ONCE AGAIN CONTINUE...SO
EXPECT SEVERE THREAT TO BE LIMITED.
MODELS DISAGREE ON THE PLACEMENT OF THE LOW BY THE SUNDAY
TIMEFRAME WITH THE ECMWF FURTHER NORTH OVER SE COLORADO.
COMPARATIVELY...THE GFS HOLDS THE LOW CENTER FURTHER SOUTH NR THE
TX/OK PANHANDLES. THE LOCATION WILL HAVE A LARGE RANGING IMPACT ON
THUNDERSTORM CHANCES...WITH THE GFS SIGNIFICANTLY DRIER THAN THE
ECMWF. AM NOT CONFIDENT IN EITHER SCENARIO THIS FAR OUT...SO HAVE
GENERALLY STEERED THE FORECAST TOWARDS A BLEND OF THE TWO. THAT
SAID...IF THE ECMWF VERIFIES THE FORECAST WILL BE TOO
LOW...BUT TOO HIGH IF THE GFS COMES TRUE.
MODEL DIFFERENCES CONTINUE IN THE LOW PLACEMENT FOR MEMORIAL DAY
WITH THE ECMWF LIFTING IT NORTHEAST INTO NEBRASKA AND THE GFS
HOLDS IT SOUTH NR THE TX PANHANDLE. IN EITHER SCENARIO...EXPECT A
DRIER AIR MASS TO END AFTERNOON/EARLY EVENING THUNDERSTORM
CHANCES FOR MONDAY.
THE SLOW PROGRESSING PATTERN WILL CAUSE VERY LITTLE VARIATION IN
TEMPERATURES THRU THE EXTENDED WITH HIGH TEMPERATURES GENERALLY
RANGING FROM 65-75 DEGREES OVR LOWER ELEVATIONS. THIS STRETCH OF
WARM DAYS ALONG WITH PERIODIC RAIN CHANCES WILL CONTINUE TO
HEIGHTEN FLOODING CONCERNS AS SNOWMELT RAMPS UP IN EARNEST NR THE
SE WY MOUNTAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1129 AM MDT TUE MAY 20 2014
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON AND EVENING. INITIAL ACTIVITY
WILL BE OVER THE HIGHER TERRAIN OF SOUTHEAST WYOMING AFTER 20 UTC
BEFORE SPREADING INTO THE PANHANDLE LATER IN THE DAY. THESE STORMS
MAY PRODUCE LARGE HAIL AND GUSTY/ERRATIC WINDS...AS WELL AS BRIEF
MVFR CIGS OR VSBYS. WESTERN TERMINALS WILL SEE WIND GUSTS BETWEEN
25 AND 30 KTS THROUGH EARLY EVE OUTSIDE OF THUNDERSTORMS. MOIST
SOUTHEAST FLOW MAY RESULT IN LOW STRATUS AND MVFR CIGS BELOW 3000
FEET AGL AT KCYS AROUND 12-15 UTC WED.
&&
.FIRE WEATHER...
ISSUED AT 333 AM MDT TUE MAY 20 2014
CONCERNS TO REMAIN LOW FOR THE REST OF THE WEEK WITH CONDITIONS
AND FUELS EXPECTED TO REMAIN NON-CRITICAL. SCATTERED AFTERNOON AND
EVENING THUNDERSTORMS WILL MOVE ACROSS MAINLY EASTERN DISTRICTS
MOST DAYS WITH WETTING RAINS FROM MOST OF THESE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...CLAYCOMB
SHORT TERM...RE
LONG TERM...HAHN
AVIATION...HAMMER
FIRE WEATHER...RE