Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/22/14
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 DENVER/BOULDER CO
837 PM MDT WED MAY 21 2014
.UPDATE...
ISSUED AT 815 PM MDT
STRONG/SEVERE STORMS HAVE DIMINISHED OVER THE NORTHEAST PLAINS OF
COLORADO THIS EVENING AS ALL WATCHES HAVE BEEN CANCELLED. THERE IS
A WIDESPREAD AREA OF MAINLY LIGHT TO MODERATE RAIN OVER THE FAR
NORTHEAST PLAINS. ADDITIONAL WEAKER STORMS HAVE REDEVELOPED OVER
THE FOOTHILLS AND NORTH OF DENVER AND INTO WELD COUNTY. STILL NOT
EXPECTING ANY MORE SEVERE STORMS. LATEST HRRR SHOWS THIS GENERAL
STORM TRACK WITH DIMINISHING ACTIVITY AFTER MIDNIGHT. STILL COULD
BE SOME STRATUS THAT MOVES BACK INTO THE FRONT RANGE LATER TONIGHT
WITH RESIDUAL MOISTURE FROM THE EVENING STORMS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 320 PM MDT WED MAY 21 2014
DEEP UPPER LEVEL TROUGH OVER THE GREAT BASIN MAKES LITTLE PROGRESS
EASTWARD DURING THE NEXT 24 HOURS. A MOIST AND UNSTABLE SOUTHERLY
FLOW AHEAD OF THIS TROUGH WILL AGAIN FEED SHOWER AND THUNDERSTORM
DEVELOPMENT ACROSS MOST OF THE FORECAST AREA ON THURSDAY. STORMS
TOMORROW LOOK MORE MULTI-CELL IN COVERAGE RATHER THAN SINGLE
SUPERCELL STRUCTURES LIKE THE CELL NOW EXITING THE DENVER METRO
AREA. COULD SEE A CONTINUOUS LINE OF STORMS FORMING FIRST OVER
THE FRONT RANGE BEFORE DRIFTING VERY SLOWLY EASTWARD ONTO THE
NEARBY PLAINS BY EARLY TO MID-AFTERNOON. SOUTHERLY SLOW ALOFT MAY
CREATE TRAINING OF STORM CELLS POSSIBILITY RESULTING IN POCKETSOF
HEAVY RAINFALL. PW VALUES ARE FORECAST IN THE 0.80 TO 0.90 INCH
RANGE WHICH COULD POTENTIALLY RESULT IN MAX RAINFALL AMOUNTS
UPWARDS OF 1.5 TO 1.8 INCHES. THEREFORE THE RISK OF FLOODING/FLASH
FLOODING MAY BE GREATER TOMORROW.
OTHERWISE...THE DENVER METRO AREA SUPERCELL WILL LIKELY CONTINUE
TO TRACK EAST-NORTHEAST DOWN THE I-76/SOUTH PLATTE RIVER CORRIDOR
DURING THE NEXT 3-5 HOURS. A TORNADO WATCH FOR MOST OF NORTHEAST
COLORADO IS SLATED TO EXPIRE AT 8 PM MDT. STORMS DEVELOPING LATER
THIS EVENING ACROSS THE NORTHEAST CORNER OF COLORADO ARE MORE LIKELY
TO PRODUCE LARGE HAIL AND HEAVY RAINFALL...THAN TORNADOES AS DEEP
LAYER SHEAR/INSTABILITY NOT AS GREAT OUT THERE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 PM MDT WED MAY 21 2014
THURSDAY NIGHT AND FRIDAY...THE UPPER LOW WILL BE LOCATED OVER
WEST CENTRAL ARIZONA WITH A WEAKER SOUTHERLY FLOW ALOFT OVER
NERN CO. DUE TO THE WEAK FLOW ALOFT AND SUBTROPICAL NATURE OF THE
AIRMASS...THE POTENTIAL FOR HEAVY RAIN PRODUCING THUNDERSTORMS
WILL CONTINUE ESPECIALLY FROM THE FRONT RANGE FOOTHILLS EASTWARD.
THE UPPER LOW MAKES ITS WAY SLOWLY EASTWARD FRIDAY NIGHT AND
SATURDAY WITH A WEAK S-SELY FLOW ALOFT OVER ERN CO. AS A
RESULT...THUNDERSTORMS WITH HEAVY RAIN WILL CONTINUE TO BE THE
PRIMARY AREA OF CONCERN. SATURDAY NIGHT INTO SUNDAY...THE UPPER
LOW OPENS UP AND LIFTS NORTHEAST...WITH THE AXIS SLIPPING OVER
EASTERN CO AROUND 00Z MONDAY. ONE MORE POTENTIAL DAY FOR
THUNDERSTORMS... SOME WITH HEAVY RAIN. BY MONDAY THE TROF WILL BE
OVER THE OK/TX PANHANDLES WITH A DRIER NORTHWESTERLY FLOW OVER THE
CWFA. SLGT CHC OF STORMS AT THIS TIME...WITH THE THREAT OF HEAVY
RAIN SHIFTING TO THE EAST OF COLORADO. AN UPPER RIDGE MOVES OVER
COLORADO FOR TUESDAY AND WEDNESDAY...WITH DRIER AND WARMER WEATHER
RETURNING TO THE REGION.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 815 PM MDT WED MAY 21 2014
CURRENT STORMS SHOULD STAY JUST NORTH AND WEST OF KDEN BUT
ADDITIONAL SHOWERS FURTHER WEST OVER THE MOUNTAINS MAY STILL
EFFECT BJC BEFORE MIDNIGHT. NOT SURE HOW MUCH STRATUS WILL STILL
BE AROUND LATER TONIGHT AND FOG POTENTIAL MAY BE OVERDONE. WILL
REEVALUATE FOR THE 06Z ISSUANCE.
&&
.HYDROLOGY...
ISSUED AT 320 PM MDT WED MAY 21 2014
THE THREAT OF HEAVY RAINFALL LEADING TO FLOODING WILL REMAIN LOW
FOR THE MOUNTAINS...FRONT RANGE FOOTHILLS AND MOST OF THE
NORTHEAST PLAINS OF COLORADO THE REST OF THIS AFTERNOON AND
TONIGHT. WHEREAS THE BATCH OF STRONG TO SEVERE THUNDERSTORMS
MOVING NORTHEAST ALONG THE SOUTH PLATTE/INTERSTATE 76 CORRIDOR
WILL HAVE THE POTENTIAL TO PRODUCE UPWARDS OF TWO INCHES OF RAIN
IN UNDER AN HOUR. IN ADDITION...HAIL UP TO 2 INCHES IN DIAMETER IS
ALSO LIKELY WITH THESE THUNDERSTORMS. ON THURSDAY ANOTHER ROUND OF
THUNDERSTORMS CAN BE EXPECTED FOR MOST OF NORTH CENTRAL AND
NORTHEAST COLORADO. AFTERNOON STORMS OVER AND NEAR THE FRONT RANGE
WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL AND
HAIL POSSIBLY RESULTING IN LOCALIZED FLOODING AND/OR ACCELERATE
SNOWMELT. PW VALUES ARE FORECAST IN THE 0.80 TO 0.90 INCH
RANGE WHICH COULD POTENTIALLY RESULT IN MAX RAINFALL AMOUNTS
UPWARDS OF 1.5 TO 1.8 INCHES. THEREFORE THE RISK OF FLOODING/FLASH
FLOODING MAY BE GREATER TOMORROW.
THURSDAY NIGHT AND BEYOND...NOT MUCH CHANGE IN THE FORECAST
REGARDING THE THREAT FOR HEAVY RAINFALL. SLOW STORM MOVEMENT WITH
FORECAST PW AMOUNTS OF 0.80 INCHES COULD BE A POTENTIAL ISSUE FOR
THE FOOTHILLS FOR FRIDAY AND SATURDAY. A LESSER THREAT ON SUNDAY
BUT THE POTENTIAL FOR HEAVY RAIN MAY LINGER. DRY AND WARMER
TEMPERATURES FOR EARLY NEXT WEEK.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ENTREKIN
SHORT TERM...BAKER
LONG TERM...COOPER
AVIATION...ENTREKIN
HYDROLOGY...COOPER
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 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 TAUNTON MA
1010 PM EDT WED MAY 21 2014
.SYNOPSIS...
COOLER AND OCCASIONALLY SHOWERY WEATHER IS EXPECTED THURSDAY
THROUGH SATURDAY. THROUGH THE REMAINDER OF THE HOLIDAY
WEEKEND...LOOKS LIKE WARMER CONDITIONS ARRIVE ESPECIALLY ON
MEMORIAL DAY. SCATTERED SHOWERS MAY MOVE IN FOR NEXT TUESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
1010 PM UPDATE...
LOW CONFIDENCE FORECAST CONTINUES. THE FIRST CONCERN IS THE
POTENTIAL FOR FOG TO ADVECT IN OFF THE OCEAN AND INTO EASTERN MA
OVERNIGHT. AREAS OF FOG HAVE DEVELOPED ACROSS THE OUTER-CAPE AND
NANTUCKET AS OF 10 PM. THERE WAS ALSO FOG TO THE NORTHEAST OR OUR
COUNTY WARNING AREAS...AFFECTING THE PORTSMOUTH NH TO PORTLAND ME
REGION. STILL UNCERTAIN AS TO HOW MUCH FOG WILL DEVELOP ALONG THE
REST OF THE EASTERN MA COAST AND EXACT VISIBILITIES. GIVEN TRENDS
THINK THAT COOLING BOUNDARY LAYER WILL PROMOTE SOME FOG...BUT UNSURE
IF IT WILL BE DENSE.
AS FOR PRECIPITATION POTENTIAL...WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WERE WORKING ACROSS PORTIONS OF WESTERN NY/WESTERN PA.
HOWEVER...INSTABILITY/LOW LEVEL MOISTURE IS LACKING ACROSS OUR
REGION. NOT SURE HOW MUCH OF THIS ACTIVITY WILL SURVIVE AS IT
PUSHES EAST INTO OUR REGION. FOR NOW THINKING BEST SHOT OF
SCATTERED SHOWERS WILL BE ACROSS OUR SOUTHWEST ZONES TOWARD DAYBREAK
AS THE HRRR MODEL SHOWS. HOWEVER...A FEW SHOWERS WILL BE POSSIBLE
TOWARD DAYBREAK JUST ABOUT ANYWHERE BUT BY NO MEANS A WASHOUT.
LOW TEMPS BY DAYBREAK WILL FALL IN THE UPPER 40S TO MIDDLE 50S
ACROSS THE REGION.
&&
.SHORT TERM /THURSDAY NIGHT/...
MORE OF THE SAME THROUGH THU NIGHT. MARITIME AIRMASS TAKES HOLD
ACROSS E NEW ENG AS SFC HIGH NOSES DOWN FROM THE N AND LOW PRES
CUTS OUT TO THE S YIELDING A COOL EASTERLY FLOW. COLUMN MOISTURE
DEEPENS WITH A FEW SHORTWAVES BRINGING A CHANCE OF SHOWERS FROM
TIME TO TIME WITH HIGHEST PROBABILITY IN THE WEST WHERE MOISTURE
AND INSTABILITY IS GREATER. BUT A WASHOUT IS NOT EXPECTED. SOME
ELEVATED INSTABILITY IS PRESENT ACROSS W ZONES WHERE AN ISOLD TSTM
IS POSSIBLE.
WITH EASTERLY FLOW ENTRENCHED ACROSS SNE...WE HAVE HIGH
CONFIDENCE OF MAINLY CLOUDY SKIES AND COOL TEMPS. HIGHS WILL RANGE
FROM THE UPPER 50S NEAR THE COAST AND HIGHER ELEVATIONS...TO 60-65
ELSEWHERE.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...
- CONTINUED COOL AND DAMP FOR FRIDAY...GREATEST RAIN THREATS W
- SEASONABLE SATURDAY/SUNDAY WITH DAYTIME SHOWERS AND T-STORMS
- UNCERTAIN EARLY-WEEK FORECAST...WARMING OR REMAINING COOL?
/ OVERVIEW AND MODEL PREFERENCE...
LOW THROUGH THE SW-CONUS WILL GRADUALLY MIGRATE E INTO THE CENTRAL
CONUS AMPLIFYING A RIDGE PATTERN DOWNSTREAM WHICH WILL GRADUALLY
NUDGE THE TROUGH PATTERN ACROSS THE REGION E AND OFFSHORE. WOULD
EXPECT A WARMING-TREND WITH THE TRANSITION...BUT IT IS PERHAPS THAT
WITH THE TROUGH REMAINING IN CLOSE PROXIMITY THAT THE NE-CONUS FINDS
ITSELF WAVERING BETWEEN THE AIRMASSES.
PREFER A CONSENSUS BLEND OF FORECAST GUIDANCE THROUGH THE WEEKEND
THOUGH NOT INCREDIBLY IN FAVOR OF THE PRECIPITATION BULLS-EYES PER
THE 21.12Z NAM. AS FOR THE EARLY WEEK...PREFER AN ENSEMBLE BLEND
BETWEEN THE GFS AND EC...ALSO INCORPORATING THE DETERMINISTIC EC.
FEEL THE 21.12Z GFS IS AN OUTLIER. ITS WORTH EVALUATING...BUT NOT
JUMPING ON TOP OF IT.
/ DAY-TO-DAY DETAILS...
FRIDAY...
LOW PRES DEVELOPING AND DEEPENING OFFSHORE OF NEW ENGLAND FROM WHICH
AN INVERTED TROUGH BECOMES THE FOCUS OF WET-WEATHER ACTIVITY. NOTING
MID-LEVEL ASCENT ABOVE A CONVERGENT MOIST AXIS OF DECENT THETAE WITH
WEAK INSTABILITY...HEAVY RAIN AND ISOLATED T-STORMS ARE EXPECTED.
BUT WITH PREFERENCE TO THE NAM/EC/CANADIAN FEEL THE THREAT WILL BE
MAINLY S/W TOWARDS THE LOWER NY HUDSON RIVER VALLEY WHILE SOUTHERN
NEW ENGLAND RESIDES BENEATH A STABLE COOL REGIME WITH E-ONSHORE
FLOW. SUCH FLOW UNDERGOING OROGRAPHIC LIFT WILL RESULT IN OVERCAST
LOW CLOUDS AND DRIZZLE...RESULTING IN COOL AND DAMP CONDITIONS WITH
BELOW-NORMAL TEMPERATURES /ESPECIALLY TO THE W...COULD SEE SOME
IMPROVEMENT TO THE E LATER IN THE DAY/.
ACTIVITY CONCLUDES DURING THE OVERNIGHT PERIOD. DAMP CONDITIONS WILL
YIELD HIGHER DEWPOINTS. CONDITIONS GRADUALLY CLEARING UNDER BRISK
FLOW OUT OF THE N. SOME CONCERN OVER THE POSSIBILITY OF FOG WITH
ANTECEDANT RAINS...MAINLY FOR SHELTERED LOCALES. HIGHER CONFIDENCE
OF STRATUS ELSEWHERE.
SATURDAY INTO SUNDAY...
CYCLONIC FLOW PERSISTS AS A RIDGE BUILDS IN FROM THE W. WILL SEE A
CLASH OF AIRMASSES ALONG A MID-LEVEL WARM-FRONT /PERHAPS A SURFACE
REFLECTION/ THROUGH WHICH DISTURBANCES SHOULD INVOKE LIFT. COMBINED
WITH DAYTIME HEATING AND STEEPENING MID-LEVEL LAPSE RATES /AS COOLER
AIR ENTRAINS TO THE REAR OF THE LOW...COLD-POOL ALOFT/ RESULTING IN
BOUNDARY LAYER DESTABILIZATION...EXPECT DIURNAL CHANCES OF SHOWERS
AND THUNDERSTORMS. GREATEST CONFIDENCE OF OUTCOMES OVER THE INTERIOR
AND AWAY FROM THE SEA-BREEZING SHORES.
UNCERTAIN AS TO WHETHER CLOUDS ASSOCIATED WITH DISTURBANCES WILL
LIMIT DESTABILIZATION. YET FEEL WITH WEAK INSTABILITY AND FORCING
THAT ISOLATED THUNDERSTORMS ARE TO BE ANTICIPATED. CONSIDERING AN
INVERTED-V PROFILE...MAIN THREAT WITH ANY STORMS WILL BE GUSTY WINDS
ALONG WITH HEAVY RAIN. CONTINUE TO FEEL THREATS WILL TAKE PLACE
DURING THE MIDDAY INTO THE EVENING AS ACTIVITY IS DIURNALLY-DRIVEN.
WINDS TURNING MORE WESTERLY AT THE SURFACE WITH SEA-BREEZES LIKELY
ALONG THE SHORES. EXPECTING SEASONABLE TEMPERATURES.
EARLY NEXT WEEK...
TOUGH PATTERN TO DECIPHER. MAKE YOUR PICK...COLD OR WARM? TAKING
INTO ACCOUNT THE LIKELIHOOD OF RIDGING REMAINING PROMINENT AHEAD OF
THE CENTRAL-CONUS LOW...AND THE NEAR-NEUTRAL NAO TREND...FEEL THE
TROUGH PATTERN THOUGH SHIFTING E WILL REMAIN IN CLOSE PROXIMITY TO
OUR REGION. THIS RESULTS IN THE CLASH OF AIRMASSES ACROSS THE NE
CONUS.
FAVOR THE H5 GEFS MEANS ALONG WITH A BLEND OF THE DETERMINISTIC AND
ENSEMBLE EC. THIS RESULTS IN A BUILDING RIDGE FROM THE W AS THE
TROUGH IS HELD NEARLY STATIONARY ACROSS THE NW ATLANTIC. SPECULATE A
DRY FORECAST PERIOD BUT SHOULD WAVES EMERGE THROUGH THE W-PERIPHERY
OF CYCLONIC LIKELY COLLOCATED WITH A SURFACE TO MID-LEVEL WARM FRONT
FEATURE...THEN ACTIVITY IS POSSIBLE.
WILL KEEP THE GREATEST CHANCES ACROSS THE INTERIOR DIURNALLY-DRIVEN
FIGURING THE WARM CONDITIONS AND POSSIBLE LIGHT FLOW WILL YIELD SEA-
BREEZES ALONG THE COAST. WILL KEEP CONDITIONS NEAR-SEASONABLE
LEVELS.
NOT EVEN ENTIRELY SOLD ON THE DAY-8 SIGNALS IN THE NAEFS/CANADIAN
SHOWING A H5 POSITIVE HEIGHT ANOMALY INTO E-CANADA WITH WARMER THAN
AVERAGE CONDITIONS ACROSS THE NE-CONUS. IT IS PERHAPS THAT SUCH
TRENDS ARE SLOWED AND HELD FURTHER W AGAINST PREVALENT TROUGHING TO
THE E.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...MODERATE CONFIDENCE.
WEBCAMS SHOWING THE OCEAN-FOG ROLLING IN ACROSS THE E-COASTLINE OF
MASSACHUSETTS. TRENDING WITH THE E/SE SURFACE WINDS OVERNIGHT...
WILL PREVAIL 1/2SM FG VV002 WHERE CONFIDENCE IS HIGHEST WHEREAS
TEMPO LIFR-VLIFR WITH CONFIDENCE IS MODERATE.
ANY OCEAN-FOG WILL HOPEFULLY MIX-OUT DURING THE MORNING HOURS.
THEREAFTER WILL SEE A W-E SLOW DETERIORATION OF CONDITIONS AS
SCT -SHRA AND ISOLATED TSRA SPREAD ACROSS S NEW ENGLAND. HIGHEST
CONFIDENCE OF MVFR-IFR MIX OF CONDITIONS ACROSS CT-RIVER VALLEY
TERMINALS INCLUDING ORH THROUGH THE DAY THURSDAY.
OVERNIGHT THURSDAY...EXPECTING SCT -SHRA AND ISOLATED TSRA
ACTIVITY TO CONTINUE MAINLY ACROSS W AND CENTRAL NEW ENGLAND
WHEREAS MVFR-IFR STRATUS WITH -DZ SPREAD IN FROM THE E. THE RE-
EMERGENCE OF DENSE FOG IS POSSIBLE FOR THE E-SHORELINE.
KBOS TAF...MODERATE CONFIDENCE. NEAR-TERM FORECAST GUIDANCE
SIGNALS THAT DENSE FOG WILL MOVE IN OVERNIGHT. WILL TEMPO FOR NOW
ALLOWING THE EVENING SHIFT TO MONITOR AND AMEND AS NECESSARY. NOT
ENTIRELY CONFIDENT IT WILL CLEAR OUT QUICKLY SHOULD OVC MID- TO
HIGH-LEVEL CLOUD DECKS BE IN PLACE.
KBDL TAF...MODERATE CONFIDENCE. COVERAGE OF -SHRA SHOULD INCREASE
THROUGH THE TAF PERIOD. GRADUAL DECLINE OF CONDITIONS EXPECTED
WITH LOWEST DURING THE THURSDAY OVERNIGHT PERIOD.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY...MODERATE CONFIDENCE.
MVFR-IFR MIX ESP TO THE W ALONG WITH GREATEST CHANCE OF -SHRA AND
ISOLATED TSRA. -DZ ELSEWHERE. MAY SEE SOME IMPROVEMENT TO THE E
DURING THE DAY. E-FLOW WITH GUSTS UP TO 20 KTS. OVERALL IMPROVEMENT
OVERNIGHT THOUGH THERE IS THE POSSIBILITY OF IFR-FOG IN SHELTERED
INTERIOR VALLEYS.
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
LOW-END VFR. SCT -SHRA WITH ISOLATED TSRA. TEMPO IFR WITH TSRA ALONG
WITH THE POSSIBILITY OF GUSTY WINDS. OTHERWISE WINDS BACKING W.
MONDAY...LOW CONFIDENCE.
VFR WITH W-WINDS. GUSTS UP TO AROUND 25 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.
MAINLY LIGHT EASTERLY WINDS 15 KT OR LESS AND AND SEAS BELOW 4 FT
THROUGH THE PERIOD AS WEAK HIGH PRES DEVELOPS FROM FROM THE GULF
OF MAINE TO EAST OF SNE.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY...MODERATE CONFIDENCE.
E/NE WINDS WITH GUST UP TO 20 KTS COULD RESULT IN SEAS UP TO 5 FEET
ON THE S-OUTER WATERS. LOW CLOUDS AND DRIZZLE AN ISSUE DURING THE
MORNING PERIOD...BUT IMPROVING LATE IN THE DAY AND CONTINUING IN THE
OVERNIGHT HOURS /BEST CHANCES OVER THE E-WATERS/.
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
OVERALL BRISK NE WINDS GRADUALLY VEERING OUT OF THE S. WILL SEE
WAVES POSSIBLY UP TO 5 FEET CONTINUE ON THE S-OUTER WATERS INITIALLY
THEN GRADUALLY DIMINISH. SEA-BREEZES ALONG THE IMMEDIATE SHORES
DURING THE DAY.
MONDAY...LOW CONFIDENCE.
W-WINDS WITH GUSTS UP TO 25 KTS. SEAS ON THE OUTER-WATERS GETTING UP
TO 5 FEET.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...FRANK
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
728 PM EDT WED MAY 21 2014
.SYNOPSIS...
COOLER AND OCCASIONALLY SHOWERY WEATHER IS EXPECTED THURSDAY
THROUGH SATURDAY. THROUGH THE REMAINDER OF THE HOLIDAY
WEEKEND...LOOKS LIKE WARMER CONDITIONS ARRIVE ESPECIALLY ON
MEMORIAL DAY. SCATTERED SHOWERS MAY MOVE IN FOR NEXT TUESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
7 PM UPDATE...
TWO AREAS OF FOCUS:
1. OCEAN FOG ALONG THE E-WATERS.
ALREADY SEEING PER WEBCAMS THAT VISIBILITIES ARE QUICKLY TANKING
ACROSS THE S-SIDE OF CAPE ANN AND CHATHAM WITH THE OCEAN-FOG
ROLLING IN. EVALUTING SURFACE WINDS WHICH WILL BE E/SE AND
FOLLOWING THE TRENDS OF THE HRRR AND THE RAP...HAVE THE AREAS OF
DENSE FOG WITH VISIBILITIES DOWN TO A HALF-MILE ROLLING ONTO SHORE
OVER THE NEXT SEVERAL HOURS MAINLY IMPACTING THE IMMEDIATE E-COAST
OF MA AND CAPE COD. OCEAN-FOG WILL LINGER TOWARDS SUNRISE BY WHICH
POINT BOUNDARY LAYER MIXING SHOULD HOPEFULLY SCOUR OUT THE
ACTIVITY...BUT THERE IS NO CERTAINTY IF WE CONSIDER MID- TO HIGH-
CLOUDS STREAMING OVERHEAD LIMITING SUNSHINE AND SUBSEQUENT DAYTIME
MIXING.
2. SHOWERS INTO THE CT-RIVER VALLEY.
AGREE WITH THE PREVIOUS FORECAST...STILL A LOW CONFIDENCE FORECAST
WITH REGARDS TO TIMING AND COVERAGE OF SHOWER ACTIVITY. NOTING THE
PROXIMITY OF WEAK IMPULSES THROUGH THE LONG-WAVE FLOW REGIME CO-
LOCATED WITH FALLING HEIGHTS SUBSEQUENTLY INCREASING CONVERGENCE
ALONG THE SURFACE TO MID-LEVEL WARM-FRONT /QG-FORCING AS NOTED BY
THE PREVIOUS FORECASTER/...HAVE HIGHER CONFIDENCE TO THE W AS TO
SHOWER- CHANCES DURING THE OVERNIGHT PERIOD INTO THE MORNING. THE
ONSHORE E-FLOW AND MORE STABLE REGIME COUPLED WITH THE INFLUENCE
OF HIGH PRESSURE AND SUBSIDENCE SHOULD LIMIT THE E-EXTENT OF
ACTIVITY.
HIGHER THETA-E AIR AND ELEVATED INSTABILITY TO THE W PRESENT AN
ISOLATED THREAT OF THUNDERSTORMS. WILL NEED TO MONITOR ACTIVITY
ADVECTING NW-SE FROM THE GREAT LAKES REGION WHICH PRESENTLY
CONTAINS SOME DISCREET CELLS.
OTHERWISE...
THE REMAINDER OF THE FORECAST LOOKS TO BE ON TRACK. SOME MINOR
TWEAKS TO THE NEAR-TERM CONDITIONS TO ACCOUNT FOR FOG WHICH WITH
HIGHER DEWPOINTS WILL KEEP CONDITIONS MILD. LOWS DOWN AROUND THE
UPPER-40S TO LOW-50S.
&&
.SHORT TERM /THURSDAY NIGHT/...
MORE OF THE SAME THROUGH THU NIGHT. MARITIME AIRMASS TAKES HOLD
ACROSS E NEW ENG AS SFC HIGH NOSES DOWN FROM THE N AND LOW PRES
CUTS OUT TO THE S YIELDING A COOL EASTERLY FLOW. COLUMN MOISTURE
DEEPENS WITH A FEW SHORTWAVES BRINGING A CHANCE OF SHOWERS FROM
TIME TO TIME WITH HIGHEST PROBABILITY IN THE WEST WHERE MOISTURE
AND INSTABILITY IS GREATER. BUT A WASHOUT IS NOT EXPECTED. SOME
ELEVATED INSTABILITY IS PRESENT ACROSS W ZONES WHERE AN ISOLD TSTM
IS POSSIBLE.
WITH EASTERLY FLOW ENTRENCHED ACROSS SNE...WE HAVE HIGH
CONFIDENCE OF MAINLY CLOUDY SKIES AND COOL TEMPS. HIGHS WILL RANGE
FROM THE UPPER 50S NEAR THE COAST AND HIGHER ELEVATIONS...TO 60-65
ELSEWHERE.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...
- CONTINUED COOL AND DAMP FOR FRIDAY...GREATEST RAIN THREATS W
- SEASONABLE SATURDAY/SUNDAY WITH DAYTIME SHOWERS AND T-STORMS
- UNCERTAIN EARLY-WEEK FORECAST...WARMING OR REMAINING COOL?
/ OVERVIEW AND MODEL PREFERENCE...
LOW THROUGH THE SW-CONUS WILL GRADUALLY MIGRATE E INTO THE CENTRAL
CONUS AMPLIFYING A RIDGE PATTERN DOWNSTREAM WHICH WILL GRADUALLY
NUDGE THE TROUGH PATTERN ACROSS THE REGION E AND OFFSHORE. WOULD
EXPECT A WARMING-TREND WITH THE TRANSITION...BUT IT IS PERHAPS THAT
WITH THE TROUGH REMAINING IN CLOSE PROXIMITY THAT THE NE-CONUS FINDS
ITSELF WAVERING BETWEEN THE AIRMASSES.
PREFER A CONSENSUS BLEND OF FORECAST GUIDANCE THROUGH THE WEEKEND
THOUGH NOT INCREDIBLY IN FAVOR OF THE PRECIPITATION BULLS-EYES PER
THE 21.12Z NAM. AS FOR THE EARLY WEEK...PREFER AN ENSEMBLE BLEND
BETWEEN THE GFS AND EC...ALSO INCORPORATING THE DETERMINISTIC EC.
FEEL THE 21.12Z GFS IS AN OUTLIER. ITS WORTH EVALUATING...BUT NOT
JUMPING ON TOP OF IT.
/ DAY-TO-DAY DETAILS...
FRIDAY...
LOW PRES DEVELOPING AND DEEPENING OFFSHORE OF NEW ENGLAND FROM WHICH
AN INVERTED TROUGH BECOMES THE FOCUS OF WET-WEATHER ACTIVITY. NOTING
MID-LEVEL ASCENT ABOVE A CONVERGENT MOIST AXIS OF DECENT THETAE WITH
WEAK INSTABILITY...HEAVY RAIN AND ISOLATED T-STORMS ARE EXPECTED.
BUT WITH PREFERENCE TO THE NAM/EC/CANADIAN FEEL THE THREAT WILL BE
MAINLY S/W TOWARDS THE LOWER NY HUDSON RIVER VALLEY WHILE SOUTHERN
NEW ENGLAND RESIDES BENEATH A STABLE COOL REGIME WITH E-ONSHORE
FLOW. SUCH FLOW UNDERGOING OROGRAPHIC LIFT WILL RESULT IN OVERCAST
LOW CLOUDS AND DRIZZLE...RESULTING IN COOL AND DAMP CONDITIONS WITH
BELOW-NORMAL TEMPERATURES /ESPECIALLY TO THE W...COULD SEE SOME
IMPROVEMENT TO THE E LATER IN THE DAY/.
ACTIVITY CONCLUDES DURING THE OVERNIGHT PERIOD. DAMP CONDITIONS WILL
YIELD HIGHER DEWPOINTS. CONDITIONS GRADUALLY CLEARING UNDER BRISK
FLOW OUT OF THE N. SOME CONCERN OVER THE POSSIBILITY OF FOG WITH
ANTECEDANT RAINS...MAINLY FOR SHELTERED LOCALES. HIGHER CONFIDENCE
OF STRATUS ELSEWHERE.
SATURDAY INTO SUNDAY...
CYCLONIC FLOW PERSISTS AS A RIDGE BUILDS IN FROM THE W. WILL SEE A
CLASH OF AIRMASSES ALONG A MID-LEVEL WARM-FRONT /PERHAPS A SURFACE
REFLECTION/ THROUGH WHICH DISTURBANCES SHOULD INVOKE LIFT. COMBINED
WITH DAYTIME HEATING AND STEEPENING MID-LEVEL LAPSE RATES /AS COOLER
AIR ENTRAINS TO THE REAR OF THE LOW...COLD-POOL ALOFT/ RESULTING IN
BOUNDARY LAYER DESTABILIZATION...EXPECT DIURNAL CHANCES OF SHOWERS
AND THUNDERSTORMS. GREATEST CONFIDENCE OF OUTCOMES OVER THE INTERIOR
AND AWAY FROM THE SEA-BREEZING SHORES.
UNCERTAIN AS TO WHETHER CLOUDS ASSOCIATED WITH DISTURBANCES WILL
LIMIT DESTABILIZATION. YET FEEL WITH WEAK INSTABILITY AND FORCING
THAT ISOLATED THUNDERSTORMS ARE TO BE ANTICIPATED. CONSIDERING AN
INVERTED-V PROFILE...MAIN THREAT WITH ANY STORMS WILL BE GUSTY WINDS
ALONG WITH HEAVY RAIN. CONTINUE TO FEEL THREATS WILL TAKE PLACE
DURING THE MIDDAY INTO THE EVENING AS ACTIVITY IS DIURNALLY-DRIVEN.
WINDS TURNING MORE WESTERLY AT THE SURFACE WITH SEA-BREEZES LIKELY
ALONG THE SHORES. EXPECTING SEASONABLE TEMPERATURES.
EARLY NEXT WEEK...
TOUGH PATTERN TO DECIPHER. MAKE YOUR PICK...COLD OR WARM? TAKING
INTO ACCOUNT THE LIKELIHOOD OF RIDGING REMAINING PROMINENT AHEAD OF
THE CENTRAL-CONUS LOW...AND THE NEAR-NEUTRAL NAO TREND...FEEL THE
TROUGH PATTERN THOUGH SHIFTING E WILL REMAIN IN CLOSE PROXIMITY TO
OUR REGION. THIS RESULTS IN THE CLASH OF AIRMASSES ACROSS THE NE
CONUS.
FAVOR THE H5 GEFS MEANS ALONG WITH A BLEND OF THE DETERMINISTIC AND
ENSEMBLE EC. THIS RESULTS IN A BUILDING RIDGE FROM THE W AS THE
TROUGH IS HELD NEARLY STATIONARY ACROSS THE NW ATLANTIC. SPECULATE A
DRY FORECAST PERIOD BUT SHOULD WAVES EMERGE THROUGH THE W-PERIPHERY
OF CYCLONIC LIKELY COLLOCATED WITH A SURFACE TO MID-LEVEL WARM FRONT
FEATURE...THEN ACTIVITY IS POSSIBLE.
WILL KEEP THE GREATEST CHANCES ACROSS THE INTERIOR DIURNALLY-DRIVEN
FIGURING THE WARM CONDITIONS AND POSSIBLE LIGHT FLOW WILL YIELD SEA-
BREEZES ALONG THE COAST. WILL KEEP CONDITIONS NEAR-SEASONABLE
LEVELS.
NOT EVEN ENTIRELY SOLD ON THE DAY-8 SIGNALS IN THE NAEFS/CANADIAN
SHOWING A H5 POSITIVE HEIGHT ANOMALY INTO E-CANADA WITH WARMER THAN
AVERAGE CONDITIONS ACROSS THE NE-CONUS. IT IS PERHAPS THAT SUCH
TRENDS ARE SLOWED AND HELD FURTHER W AGAINST PREVALENT TROUGHING TO
THE E.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...MODERATE CONFIDENCE.
WEBCAMS SHOWING THE OCEAN-FOG ROLLING IN ACROSS THE E-COASTLINE OF
MASSACHUSETTS. TRENDING WITH THE E/SE SURFACE WINDS OVERNIGHT...
WILL PREVAIL 1/2SM FG VV002 WHERE CONFIDENCE IS HIGHEST WHEREAS
TEMPO LIFR-VLIFR WITH CONFIDENCE IS MODERATE.
ANY OCEAN-FOG WILL HOPEFULLY MIX-OUT DURING THE MORNING HOURS.
THEREAFTER WILL SEE A W-E SLOW DETERIORATION OF CONDITIONS AS
SCT -SHRA AND ISOLATED TSRA SPREAD ACROSS S NEW ENGLAND. HIGHEST
CONFIDENCE OF MVFR-IFR MIX OF CONDITIONS ACROSS CT-RIVER VALLEY
TERMINALS INCLUDING ORH THROUGH THE DAY THURSDAY.
OVERNIGHT THURSDAY...EXPECTING SCT -SHRA AND ISOLATED TSRA
ACTIVITY TO CONTINUE MAINLY ACROSS W AND CENTRAL NEW ENGLAND
WHEREAS MVFR-IFR STRATUS WITH -DZ SPREAD IN FROM THE E. THE RE-
EMERGENCE OF DENSE FOG IS POSSIBLE FOR THE E-SHORELINE.
KBOS TAF...MODERATE CONFIDENCE. NEAR-TERM FORECAST GUIDANCE
SIGNALS THAT DENSE FOG WILL MOVE IN OVERNIGHT. WILL TEMPO FOR NOW
ALLOWING THE EVENING SHIFT TO MONITOR AND AMEND AS NECESSARY. NOT
ENTIRELY CONFIDENT IT WILL CLEAR OUT QUICKLY SHOULD OVC MID- TO
HIGH-LEVEL CLOUD DECKS BE IN PLACE.
KBDL TAF...MODERATE CONFIDENCE. COVERAGE OF -SHRA SHOULD INCREASE
THROUGH THE TAF PERIOD. GRADUAL DECLINE OF CONDITIONS EXPECTED
WITH LOWEST DURING THE THURSDAY OVERNIGHT PERIOD.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY...MODERATE CONFIDENCE.
MVFR-IFR MIX ESP TO THE W ALONG WITH GREATEST CHANCE OF -SHRA AND
ISOLATED TSRA. -DZ ELSEWHERE. MAY SEE SOME IMPROVEMENT TO THE E
DURING THE DAY. E-FLOW WITH GUSTS UP TO 20 KTS. OVERALL IMPROVEMENT
OVERNIGHT THOUGH THERE IS THE POSSIBILITY OF IFR-FOG IN SHELTERED
INTERIOR VALLEYS.
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
LOW-END VFR. SCT -SHRA WITH ISOLATED TSRA. TEMPO IFR WITH TSRA ALONG
WITH THE POSSIBILITY OF GUSTY WINDS. OTHERWISE WINDS BACKING W.
MONDAY...LOW CONFIDENCE.
VFR WITH W-WINDS. GUSTS UP TO AROUND 25 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.
MAINLY LIGHT EASTERLY WINDS 15 KT OR LESS AND AND SEAS BELOW 4 FT
THROUGH THE PERIOD AS WEAK HIGH PRES DEVELOPS FROM FROM THE GULF
OF MAINE TO EAST OF SNE.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRIDAY...MODERATE CONFIDENCE.
E/NE WINDS WITH GUST UP TO 20 KTS COULD RESULT IN SEAS UP TO 5 FEET
ON THE S-OUTER WATERS. LOW CLOUDS AND DRIZZLE AN ISSUE DURING THE
MORNING PERIOD...BUT IMPROVING LATE IN THE DAY AND CONTINUING IN THE
OVERNIGHT HOURS /BEST CHANCES OVER THE E-WATERS/.
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
OVERALL BRISK NE WINDS GRADUALLY VEERING OUT OF THE S. WILL SEE
WAVES POSSIBLY UP TO 5 FEET CONTINUE ON THE S-OUTER WATERS INITIALLY
THEN GRADUALLY DIMINISH. SEA-BREEZES ALONG THE IMMEDIATE SHORES
DURING THE DAY.
MONDAY...LOW CONFIDENCE.
W-WINDS WITH GUSTS UP TO 25 KTS. SEAS ON THE OUTER-WATERS GETTING UP
TO 5 FEET.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
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
957 PM CDT WED MAY 21 2014
.DISCUSSION...
350 PM CDT
MAIN FORECAST CONCERNS ARE WITH STRONG TO SEVERE THUNDERSTORMS IN
THE NEAR TERM...AS WELL AS TEMP TRENDS INTO THE EVENING.
LATEST RADAR IMAGERY DEPICTING RAPID THUNDERSTORM DEVELOPMENT IN
AND AROUND SURFACE TROUGH/COLD FRONT ACROSS EAST CENTRAL ILLINOIS
AND NORTH CENTRAL INDIANA. OUT AHEAD OF THIS FRONT...DEWPOINTS IN
THE MID/UPPER 60S STILL RESIDE AND ARE AIDING IN MODERATE TO
STRONG INSTABILITY. INCREASING SHEAR AND STEEP LOW/MID LEVEL LAPSE
RATES ARE PROVIDING FOR SOME RATHER ROBUST DEVELOPMENT ACROSS THIS
GENERAL AREA...CLIPPING THE FAR SOUTHERN TIER OF COUNTIES...WITH
LARGE HAIL THE PRIMARY THREAT. EXPECT THIS DEVELOPMENT TO REMAIN
CONFINED TO THE CURRENT LOCATION AND SOUTHWARD OVER THE NEXT ONE
TO TWO HOURS...BEFORE THESE THUNDERSTORMS SHIFT SOUTH WITH THE
SOUTHWARD MOVEMENT TO THE FRONT. DONT ANTICIPATE ANY FURTHER
DEVELOPMENT THIS EVENING OVERNIGHT...WITH DRY CONDITIONS EXPECTED
FOR THE CWA OVERNIGHT. TEMPS ARE CURRENTLY STILL WARMING PRETTY
GOOD WITH MID/UPPER 80S OVERHEAD WITH THE EXCEPTION OF COOLER
CONDITIONS NEAR THE LAKE. AS STRONGER PRESSURE GRADIENT TO THE
NORTHWEST CONTINUES TO SHIFT EAST WITH TIME HERE IN THE NEXT
COUPLE OF HOURS...FEEL THAT A SHIFT TO THE NORTHWEST WILL STILL BE
ABLE TO HELP THE LAKE BREEZE TO RETREAT LATE THIS AFTERNOON AND
EVENING AND WITH SOME WARMING STILL POSSIBLE NEAR THE LAKE.
ONGOING COLD ADVECTION WILL CONTINUE OVERNIGHT...AND WITH CLEARING
SKIES AND MUCH DRIER AIR IN PLACE...A COOLER NIGHT IN THE 50S WILL
BE LIKELY.
RATHER QUIET CONDITIONS EXPECTED OVER THE NEXT SEVERAL DAYS AND
EVEN INTO THE WEEKEND...WITH DRY CONDITIONS LIKELY. WEAK COLD
ADVECTION WILL CONTINUE OVER THE NEXT COUPLE OF DAYS WITH COOLER
TEMPERATURES IN THE 70S/60S EXPECTED. BUILDING HIGH PRESSURE FROM
THE NORTHWEST WILL ESTABLISH ITSELF OVERHEAD BY THE END OF THE
WORK WEEK BEFORE SHIFTING TO THE EAST THROUGH THE WEEKEND. THIS
WILL OCCUR AS UPPER LEVEL RIDGING OCCURS ACROSS THE REGION...AND
WHILE WAA BRINGS A RETURN TO WARMER WEATHER. ALTHOUGH WARMER
WEATHER IS EXPECTED NEXT WEEK...IT DOES LOOK UNSETTLED WITH
SHOWER/THUNDERSTORM CHANCES WITH THE RETURN OF A MORE MOIST
ENVIRONMENT.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* LAKE BREEZE TURNS WINDS NE THURSDAY MORNING/EARLY AFTN.
JEE
//DISCUSSION...UPDATED 00Z...
LOW PRESSURE IS OVER THE EASTERN GREAT LAKES AND HIGH PRESSURE
WILL BUILD OVER THE REGION TOMORROW. GUSTY NW WINDS WILL DIMINISH
THIS EVENING. A LAKE BREEZE PUSHES ONSHORE TOMORROW AND STILL
THINKING IT WILL REACH MDW AND GYY BEFORE IT REACHES ORD. WINDS
WILL TURN NE AT ORD/MDW AND N AT GYY. DPA AND RFD WILL REMAIN WEST
WITH WINDS ARND 10 KT. MAY SEE A LOW END MVFR SCATTERED DECK
TOMORROW AS WELL.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE IN TIMING OF LAKE BREEZE TOMORROW.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY AND SATURDAY...VFR.
SUNDAY...SCHC TSRA OVERNIGHT WITH MVFR CIGS PSBL.
MONDAY...CHC TSRA...MVFR CIGS PSBL.
TUESDAY...SCHC TSRA...MVFR CIGS PSBL.
JEE
&&
.MARINE...
202 PM CDT
A FAIRLY BROAD AREA OF LOW PRESSURE IS POSITIONED OVER THE WESTERN
GREAT LAKES AND WILL MOVE EASTWARD TONIGHT AND THURSDAY. A COLD
FRONTAL BOUNDARY WILL MOVE ACROSS THE LAKE THIS EVENING WHICH WILL
BRING A STEADIER NORTHWEST WIND AS WELL AS DRIER AIR...WHICH WILL
WORK TO ERODE THE REMAINING FOG ACROSS THE OPEN WATERS LATE THIS
AFTERNOON AND EARLY THIS EVENING. GENERALLY LIGHT NORTHERLY FLOW
WILL REMAIN ACROSS THE LAKE INTO THE WEEKEND AS HIGH PRESSURE MOVES
OVER LAKE MICHIGAN. A SHIFT TO ONSHORE WINDS IS LIKELY THURSDAY AND
FRIDAY...WITH MORE VARIABILITY SATURDAY AS THE HIGH MOVES OVERHEAD.
A SHIFT TO A STEADIER SOUTHERLY WIND IS EXPECTED SATURDAY NIGHT AS
THE HIGH MOVES OFF TO THE EAST. LOW PRESSURE IS FORECAST TO TRACK
NORTHEAST ACROSS THE UPPER MIDWEST SUNDAY NIGHT AND MONDAY WHICH
WILL TIGHTEN THE PRESSURE GRADIENT LEADING TO A BIT OF AN INCREASE
IN WIND SPEEDS BUT STABLE AIR OVER THE LAKE SHOULD KEEP GUST
FREQUENCY LOW.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
842 PM CDT Wed May 21 2014
.DISCUSSION...
ISSUED 842 PM CDT Wed May 21 2014
The cold front appears to be finally making some progress
southward toward Lincoln, but it is still slow. Conditions are
setting up for an E-W line of storms to fill in ahead of the cold
front, as a shortwave moves northeast along the front. NW flow
aloft will work in conjunction with the low level dynamics to cause
some back-building of the storms to the west. Instability params
look favorable for continued strong to severe thunderstorm
development through at least 10 pm, then we should see some
stabilization of the boundary layer helping to reduce the hail
threat and shift the focus to more heavy rain from training
storms.
The latest severe thunderstorm watch is in affect until 2 am, but
hopefully we can clear most of that watch before midnight. We kept
high chance PoPs across the southern half of our forecast area,
with low chance toward Havana to Bloomington.
After midnight, precip chances should be confined to our far
southern counties as the front approaches the I-70 corridor. Some
clearing in our NW counties late tonight may allow for cooler lows
in the mid 50s, which the forecast handled well already.
The evening updates have been tied to watch issuances and
adjustments, and the latest forecast data are already available.
Shimon
&&
.AVIATION...
ISSUED 654 PM CDT Wed May 21 2014
The cold front has made slow progress this afternoon, and still extends
from Rushville to Bloomington at 00z/7 pm. Storms will be possible
for at least the first half of the evening, through 02z or 03z for
all the terminal sites except for PIA. CMI will have the highest
chances of storms in the next 2 hours, but new development could
affect SPI, DEC, and BMI. The front may linger in our forecast
area after midnight, so additional precip chances could need to be
added after 05z for SPI and DEC.
Winds ahead of the front remain southwest at 10g20kt. PIA and BMI
winds have become NW. CMI winds are highly variable near
thunderstorms, but should settle out from the NW after the line of
storms departs by late evening.
MVFR visibility conditions due to rain will most likely affect
CMI for another couple of hours. If a storm moves over the
airport, IFR vis could develop briefly.
Otherwise, expect VFR conditions for the majority of the next 24
hours at the terminal sites.
Shimon
&&
.PREV DISCUSSION...
ISSUED 158 PM CDT Wed May 21 2014
Severe storm potential will highlight the short term. A brief period
of cooler temps will close out the week, before a long wave ridge
builds into our area for the weekend. As that ridge slides east
later this weekend, a few late afternoon thunderstorms could bubble
up in our western areas on Sunday and Memorial Day as moisture
and heat return to IL.
SHORT TERM...Tonight through Saturday.
The initial severe thunderstorm watch #164 does not include any of
IL, but we still expect some thunderstorms to develop along the
cold front in IL later this afternoon. At 18z/1 pm, the front
extended on a line through Bloomington and Rushville. Surface
dewpoints ahead of the front had climbed into the mid 60s, with
air temps in the mid to upper 80s. Surface based CAPEs were in the
2800-3300 J/kg, with 0-6km wind shear of 35-50kts. LAPS soundings
were indicating little to no cap above the LCL. We should see some
of the storms become strong in our area, with very large hail the
main hazard and damaging winds possible. Supercell formation
appears likely at the onset, with the better chances of linear
progression most likely occurring after the storms advance eastward
into Indiana. The cumulus field on across C IL appears to be
deepening, with some towering cu. A watch may be needed in IL in
the 2-3 pm time frame.
Will maintain high chance PoPs the rest of the afternoon and into
the evening, as coverage could be limited by breaks in the line of
storm cells that develop.
The latest 4km model HRRR output shows rather limited coverage of
storms on an E-W line along and south of I-72, with storms
generally south of our CWA by 06z/1am. Will keep PoPs after
midnight limited to the far southern areas.
The cold front forward progress will slow down and stall near the
southern tip of IL, keeping shower and storm chances close by to
the south and west of our forecast area. We held onto a narrow
area of slight chance PoPs along our far southern counties on
Thurs and Thur night as a result.
Surface high pressure and a building ridge aloft should help keep
our area rain free on Friday and Saturday as moisture return will
be primarily into the Missouri and areas west.
A brief cooler period will occur from Thursday into Friday behind
today`s cold front. Highs will still linger right around normal in
the mid to upper 70s. Saturday will see temps begin a warming
trend, but highs will still remain mainly in the upper 70s.
LONG TERM...Sunday through Wednesday.
Warming through a deeper layer will develop on Sunday as the
surface ridge axis slides east of Illinois and southerly return
flow increases. Low and mid level moisture content will increase as
well, with dewpoints returning to the 60s west of I-55 on Sunday.
Thunderstorm chances will be mainly west of our forecast area, in
the vicinity of a surface trough along the Mississippi river
valley. Instability params support storm progression into western
IL, so we went with low chance and slight chance PoPs west of
I-55. A weakening of the surface trough and increasing cap
strength on Memorial Day may help to diminish storm chances a
little. However, an weak disturbance in the 400-600 mb layer
could cause a few isolated storms. We went with slight chance PoPs
NW of a line from Springfield to Champaign, for mainly late
afternoon/early evening storm potential. Most areas should remain
dry though. Memorial Day looks to be the warmest day of the
holiday weekend, as highs return to the mid 80s. Dewpoints in the
low to mid 60s will make it feel a bit humid outside as well.
On Tuesday and Wednesday, the ECMWF, and to some extent the GFS,
progress an upper low into the ridge, triggering a wider coverage
of showers and storms. Low chance PoPs were included for all our
counties Tuesday and Wednesday to account for the relative
agreement on a wetter solution. Increasing clouds and rain
potential should keep high temps in the 70s both days.
Shimon
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
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:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
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:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
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
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
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
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 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 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 GOODLAND KS
915 PM MDT WED MAY 21 2014
.UPDATE...
ISSUED AT 913 PM MDT WED MAY 21 2014
UPDATED GRIDS AND ZONES FOR A CANCELLATION OF PART OF THE SEVERE
WATCH. EASTERN COLORADO AND PART OF NORTHWEST KANSAS IS NO LONGER
IN THE WATCH. THE WATCH CONTINUES FOR THE EASTERN PART OF THE WATCH.
&&
.SHORT TERM...(THIS AFTERNOON INTO TONIGHT)
ISSUED AT 205 PM MDT WED MAY 21 2014
MAIN CHANGE FOR THIS TIME PERIOD WAS TO SLOW THE ONSET OF
THUNDERSTORM DEVELOPMENT. FRONT WAS DRAPED RATHER FAR SOUTH AND
ALONG THE FRONT RANGE TO THE WEST. AN AREA OF SURFACE CONVERGENCE
EXTENDED FROM KIT CARSON AND CHEYENNE COUNTIES TOWARD THE
NORTHWEST. RATHER STRONG SURFACE WINDS OCCURRING OVER THE AREA AT
THIS TIME. SHORTWAVE TROUGH OVER NEW MEXICO IS EXPECTED TO MOVE
TOWARD THE NORTHEAST THROUGH THE NIGHT WITH A SLUG OF SUBTROPICAL
MOISTURE COMING IN ADVANCE OF IT. ALSO A RIGHT REAR QUADRANT OF
THE JET STARTS OVER THE SOUTHWEST HALF OF THE AREA LATE THIS
AFTERNOON INTO THE EVENING HOURS.
THIS IS ALL STARTING A LITTLE SLOWER THAN WHAT THE EARLIER FORECAST
HAD. AREA RADARS/SATELLITE/LIGHTNING DETECTION SHOW AN AREA/LINE
OF STORMS DEVELOPING FROM SOUTHWEST KANSAS INTO SOUTHEAST COLORADO
TO ALONG THE NORTHERN COLORADO FRONT RANGE. WHERE THE MAIN PROBLEM
IS FOR THIS FORECAST IS THAT THE MODELS DISAGREE ON WHERE TO PUT
THE MAIN SWATCH OF STORMS/QPF. SOME TAKE THE MAIN AREA OVER THE
NORTHWEST HALF...SOME OVER THE SOUTHEAST PORTION CLOSEST TO THE
FRONT AND SOME DO BOTH.
THE HRRR WHICH HAS BEEN DOING WELL RECENTLY HAS TRENDED FROM
TAKING A BROKEN SWATH OF PRECIPITATION FROM SOUTHWEST TO NORTHEAST
ACROSS THE ENTIRE CWA TO THE TWO DIFFERENT AREAS OVER THE SOUTHEAST
AND NORTHWEST. ALSO THE MODELS ARE ALSO INDICATING A COUPLE OF
DIFFERENT WAVES OF PRECIPITATION. ONE THIS EVENING WITH THIS
IN ITAL WAVE AND THEN ANOTHER ONE LATER TONIGHT. ALL IN ALL THERE
LOOKS TO BE SOME KIND OF PRECIPITATION MOVING ACROSS MOST OF THE
AREA...JUST NOT SURE EXACTLY WHERE.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 228 PM MDT WED MAY 21 2014
THE FOCUS/MAIN CONCERNS FOR THE LONG TERM FORECAST PERIOD ARE SEVERE
WEATHER CHANCES AND POTENTIAL FOR HEAVY RAINS. THE PRIMARY TIME FOR
SEVERE WEATHER WITHIN THE LONG-TERM FORECAST RESIDES ON THURSDAY
AND THURSDAY NIGHT. THREAT FOR HEAVY RAINS WILL BE HIGHEST FROM
THURSDAY THROUGH SATURDAY NIGHT.
ON THURSDAY...A LULL IN CONVECTIVE ACTIVITY SEEMS PROBABLE FOR
THURSDAY MORNING BEFORE ACTIVITY ONCE AGAIN RAMPS UP IN THE
AFTERNOON. IN A SIMILAR SCENARIO TO WEDNESDAY...THUNDERSTORMS
DEVELOP TO THE SOUTH AND WEST ALONG A STALLED FRONT...CONVECTIVE
OUTFLOWS AND THE FRONT RANGE. THUNDERSTORMS THEN SPREAD NORTHEAST
ACROSS THE FORECAST AREA. INSTABILITY MAY BE HIGHER THURSDAY
COMPARED TO TODAY...HOWEVER...THE SHEAR SIGNIFICANTLY DECREASES. DO
NOT THINK THE TORNADO OR SUPERCELL THREAT IS AS HIGH FOR THURSDAY
COMPARED TO WEDNESDAY. PULSE-LIKE HAIL STORMS AND CONVECTIVE
CLUSTERS SHOULD BE THE PRIMARY STORM MODES WITH LARGE HAIL AND
DAMAGING WINDS AS THE MAIN THREAT. SOME SIGNIFICANT HAIL AT OR ABOVE
2 INCHES REMAINS POSSIBLE.
FROM THURSDAY NIGHT THROUGH MONDAY...SHOWER AND THUNDERSTORM CHANCES
CONTINUE ACROSS THE FORECAST AREA AS THE UPPER LEVEL LOW REMAINS
OVER THE WESTERN UNITED STATES. HAVE ADVERTISED THE BEST CHANCES FOR
RAIN IN THE AFTERNOON AND EVENING EACH DAY AS SHORTWAVE TROUGHS PASS
THROUGH AND DAYTIME INSTABILITY IS HIGHEST. IT IS POSSIBLE THAT
CONVECTION CONTINUES THROUGHOUT THE NIGHT ON THURSDAY AND POSSIBLY
FRIDAY. THE UPPER LEVEL LOW PRESSURE SYSTEM EJECTS OVER THE PLAINS
MONDAY AND CLEARS OUT TO THE EAST BY TUESDAY. MODELS HAVE SLOWED THE
SYSTEM SLIGHTLY SO HAVE PULLED POPS BACK TO THE WEST SOME.
WITH RESPECT TO POTENTIAL FLASH FLOODING...AGAIN THE HIGHEST
POTENTIAL FOR THIS THREAT IS BETWEEN THURSDAY NIGHT AND SATURDAY
NIGHT. PRECIPITABLE WATER READINGS APPROACH TO EXCEED 2 STANDARD
DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. SEVERAL CLUSTERS WILL
PASS THROUGH WITH HEAVY RAIN RATES AND SUFFICIENT INSTABILITY. STILL
UNSURE ABOUT THIS BECOMING A WIDESPREAD FLOODING EVENT DUE TO
UNCERTAINTY IN EXACT STORM MOVEMENT. IF THERE WERE TO BE FLASH
FLOODING...THE MOST LIKELY LOCATION IS NORTHWEST KANSAS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 535 PM MDT WED MAY 21 2014
VFR CONDITIONS DETERIORATE THIS EVENING AT KGLD AND KMCK AS A LINE
OF STORMS MOVES NORTHEAST IMPACTING KGLD AROUND 01Z AND KMCK BY
04Z. DO NOT EXPECT MORE THAN A COUPLE OF HOURS OF THUNDER AT
EITHER SITE. AFTER MIDNIGHT SOME MORE SHOWERS AND STORMS WILL
LINGER NEAR KGLD. FORECAST SOUNDINGS INDICATE POTENTIAL FOR
STRATUS AND MVFR CONDITIONS AT BOTH SITES TOWARD SUNRISE. VFR CONDITIONS
WILL RETURN BY MID MORNING. INSTABILITY WILL BRING CHANCE OF
THUNDERSTORMS AGAIN THURSDAY AFTERNOON TO BOTH SITES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...FS
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...FS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
702 PM CDT Wed May 21 2014
...Update for delaying precipitation chances and aviation
forecast...
.UPDATE...
Issued at 651 PM CDT WED MAY 21 2014
Some thunderstorm development occurring in west central KS west of
HYS in 850 mb warm advection zone...but otherwise, convection has
not really developed in vicinity of boundary draped across central
and eastern KS. Thus, expect main thunderstorm chances will be
delayed tonight until shortwave trough in water vapor imagery
approaches the area around midnight or later. Thus have updated
grids to decrease precip chances this evening.
&&
.SHORT TERM...(This Evening through Thursday)
Issued at 311 PM CDT WED MAY 21 2014
Latest surface analysis shows surface trough extending northeast
from a low over the Texas Panhandle to near Topeka then into
northwest Missouri. Dew points have increased to around 66 degrees
to the south of the boundary in east central Kansas. Cu field has
developed along and to the north of the boundary. Convergence was
still weak and capping remains in place as CIN values range from 100
to 200 J/kg at 20Z. 0-6km shear of 40 to 50 kts over the CWA and
shear is forecast to decrease some overnight to around 30 to 40 kts.
Cape was running around 2000-2500 J/kg at late afternoon. If cap is
able to be overcome then isolated thunderstorms could develop and
could become severe with hail and and wind the main Hazards. Have
left small chances for thunderstorms from late afternoon and into
the early evening hours. There does not seem to be any weak waves
that would set anything off. The HRRR and the new 18Z NAM develop
some convection this evening along the frontal boundary and in area
of 850 mb convergence and theta advection. Have increase chances
after 03Z. The next area to watch remains convection moving off the
High Plains and/or developing across south central Kansas. Models
are showing that good moisture transport will focus into central
Kansas by 06Z then veering into northeast Kansas by 12Z with the
increase of the low level jet. Corfidi vectors suggest an eastward
movement to any MCS that would develop out in western Kansas.
Precipitable water values increase to around 1.5 inches along I-70
overnight. Isolated hail and strong winds will be possible with the
MCS as it moves across the state.
Thursday, there still could be some morning convection which will
leave outflow boundaries across the area along with the frontal
boundary. Shear is not as strong as today generally in the
20 to 30 kt range and is less favorable for supercells. There is a
wave that was moving across New Mexico this afternoon that is
progged to be moving into central Kansas on Thursday. Will continue
to keep chance pops going for now. Lows tonight will range from the
lower 60s along the Nebraska border to the upper 60s across east
central Kansas. Highs Thursday will range from the mid 70s in far
northeast Kansas to the mid 80s in east central Kansas.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 311 PM CDT WED MAY 21 2014
The surface front will sag south again Thursday night in wake of
the shortwave trough that will round the upper ridge during the
day Thursday. Proximity of the boundary along with 925-850mb
20-30kt flow moving atop the sfc-850mb boundary could lead to sct
thunderstorms overnight into early Friday. Some low chcs for pops again
Friday although the upper ridge over the area and better low level
focus across western KS suggests chcs are minimal this far east.
Another upper wave will move across the region Friday night into
Saturday so that should bring better chcs for scattered
thunderstorms.
The main upper low will drift into the region Sunday and Monday.
It would appear that Sunday night into Monday would bring the
higher rain chcs as the upper low approaches the area given we
will lack a low level focus both days. The upper low will finally
depart Tuesday so precip chcs will diminish then with a dry
weather expected by mid to late week.
&&
.AVIATION...(For the 00Z TAFs through 00Z Thursday Evening)
Issued at 651 PM CDT WED MAY 21 2014
Have delayed thunderstorm chances at TAF sites til later tonight
as little development has occured in vicinity of front draped
across eastern KS. There will be a chance later tonight into Thur
morning and then again from KMHK westward by late afternoon.
Otherwise, would expect VFR cigs and vsbys and mostly easterly
winds.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GDP
SHORT TERM...53
LONG TERM...Omitt
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS GOODLAND KS
543 PM MDT WED MAY 21 2014
.SHORT TERM...(THIS AFTERNOON INTO TONIGHT)
ISSUED AT 205 PM MDT WED MAY 21 2014
MAIN CHANGE FOR THIS TIME PERIOD WAS TO SLOW THE ONSET OF
THUNDERSTORM DEVELOPMENT. FRONT WAS DRAPED RATHER FAR SOUTH AND
ALONG THE FRONT RANGE TO THE WEST. AN AREA OF SURFACE CONVERGENCE
EXTENDED FROM KIT CARSON AND CHEYENNE COUNTIES TOWARD THE
NORTHWEST. RATHER STRONG SURFACE WINDS OCCURRING OVER THE AREA AT
THIS TIME. SHORTWAVE TROUGH OVER NEW MEXICO IS EXPECTED TO MOVE
TOWARD THE NORTHEAST THROUGH THE NIGHT WITH A SLUG OF SUBTROPICAL
MOISTURE COMING IN ADVANCE OF IT. ALSO A RIGHT REAR QUADRANT OF
THE JET STARTS OVER THE SOUTHWEST HALF OF THE AREA LATE THIS
AFTERNOON INTO THE EVENING HOURS.
THIS IS ALL STARTING A LITTLE SLOWER THAN WHAT THE EARLIER FORECAST
HAD. AREA RADARS/SATELLITE/LIGHTNING DETECTION SHOW AN AREA/LINE
OF STORMS DEVELOPING FROM SOUTHWEST KANSAS INTO SOUTHEAST COLORADO
TO ALONG THE NORTHERN COLORADO FRONT RANGE. WHERE THE MAIN PROBLEM
IS FOR THIS FORECAST IS THAT THE MODELS DISAGREE ON WHERE TO PUT
THE MAIN SWATCH OF STORMS/QPF. SOME TAKE THE MAIN AREA OVER THE
NORTHWEST HALF...SOME OVER THE SOUTHEAST PORTION CLOSEST TO THE
FRONT AND SOME DO BOTH.
THE HRRR WHICH HAS BEEN DOING WELL RECENTLY HAS TRENDED FROM
TAKING A BROKEN SWATH OF PRECIPITATION FROM SOUTHWEST TO NORTHEAST
ACROSS THE ENTIRE CWA TO THE TWO DIFFERENT AREAS OVER THE SOUTHEAST
AND NORTHWEST. ALSO THE MODELS ARE ALSO INDICATING A COUPLE OF
DIFFERENT WAVES OF PRECIPITATION. ONE THIS EVENING WITH THIS
IN ITAL WAVE AND THEN ANOTHER ONE LATER TONIGHT. ALL IN ALL THERE
LOOKS TO BE SOME KIND OF PRECIPITATION MOVING ACROSS MOST OF THE
AREA...JUST NOT SURE EXACTLY WHERE.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 228 PM MDT WED MAY 21 2014
THE FOCUS/MAIN CONCERNS FOR THE LONG TERM FORECAST PERIOD ARE SEVERE
WEATHER CHANCES AND POTENTIAL FOR HEAVY RAINS. THE PRIMARY TIME FOR
SEVERE WEATHER WITHIN THE LONG-TERM FORECAST RESIDES ON THURSDAY
AND THURSDAY NIGHT. THREAT FOR HEAVY RAINS WILL BE HIGHEST FROM
THURSDAY THROUGH SATURDAY NIGHT.
ON THURSDAY...A LULL IN CONVECTIVE ACTIVITY SEEMS PROBABLE FOR
THURSDAY MORNING BEFORE ACTIVITY ONCE AGAIN RAMPS UP IN THE
AFTERNOON. IN A SIMILAR SCENARIO TO WEDNESDAY...THUNDERSTORMS
DEVELOP TO THE SOUTH AND WEST ALONG A STALLED FRONT...CONVECTIVE
OUTFLOWS AND THE FRONT RANGE. THUNDERSTORMS THEN SPREAD NORTHEAST
ACROSS THE FORECAST AREA. INSTABILITY MAY BE HIGHER THURSDAY
COMPARED TO TODAY...HOWEVER...THE SHEAR SIGNIFICANTLY DECREASES. DO
NOT THINK THE TORNADO OR SUPERCELL THREAT IS AS HIGH FOR THURSDAY
COMPARED TO WEDNESDAY. PULSE-LIKE HAIL STORMS AND CONVECTIVE
CLUSTERS SHOULD BE THE PRIMARY STORM MODES WITH LARGE HAIL AND
DAMAGING WINDS AS THE MAIN THREAT. SOME SIGNIFICANT HAIL AT OR ABOVE
2 INCHES REMAINS POSSIBLE.
FROM THURSDAY NIGHT THROUGH MONDAY...SHOWER AND THUNDERSTORM CHANCES
CONTINUE ACROSS THE FORECAST AREA AS THE UPPER LEVEL LOW REMAINS
OVER THE WESTERN UNITED STATES. HAVE ADVERTISED THE BEST CHANCES FOR
RAIN IN THE AFTERNOON AND EVENING EACH DAY AS SHORTWAVE TROUGHS PASS
THROUGH AND DAYTIME INSTABILITY IS HIGHEST. IT IS POSSIBLE THAT
CONVECTION CONTINUES THROUGHOUT THE NIGHT ON THURSDAY AND POSSIBLY
FRIDAY. THE UPPER LEVEL LOW PRESSURE SYSTEM EJECTS OVER THE PLAINS
MONDAY AND CLEARS OUT TO THE EAST BY TUESDAY. MODELS HAVE SLOWED THE
SYSTEM SLIGHTLY SO HAVE PULLED POPS BACK TO THE WEST SOME.
WITH RESPECT TO POTENTIAL FLASH FLOODING...AGAIN THE HIGHEST
POTENTIAL FOR THIS THREAT IS BETWEEN THURSDAY NIGHT AND SATURDAY
NIGHT. PRECIPITABLE WATER READINGS APPROACH TO EXCEED 2 STANDARD
DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. SEVERAL CLUSTERS WILL
PASS THROUGH WITH HEAVY RAIN RATES AND SUFFICIENT INSTABILITY. STILL
UNSURE ABOUT THIS BECOMING A WIDESPREAD FLOODING EVENT DUE TO
UNCERTAINTY IN EXACT STORM MOVEMENT. IF THERE WERE TO BE FLASH
FLOODING...THE MOST LIKELY LOCATION IS NORTHWEST KANSAS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 535 PM MDT WED MAY 21 2014
VFR CONDITIONS DETERIORATE THIS EVENING AT KGLD AND KMCK AS A LINE
OF STORMS MOVES NORTHEAST IMPACTING KGLD AROUND 01Z AND KMCK BY
04Z. DO NOT EXPECT MORE THAN A COUPLE OF HOURS OF THUNDER AT
EITHER SITE. AFTER MIDNIGHT SOME MORE SHOWERS AND STORMS WILL
LINGER NEAR KGLD. FORECAST SOUNDINGS INDICATE POTENTIAL FOR
STRATUS AND MVFR CONDITIONS AT BOTH SITES TOWARD SUNRISE. VFR CONDITIONS
WILL RETURN BY MID MORNING. INSTABILITY WILL BRING CHANCE OF
THUNDERSTORMS AGAIN THURSDAY AFTERNOON TO BOTH SITES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...FS
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
1052 PM EDT WED MAY 21 2014
.UPDATE...
ISSUED AT 1052 PM EDT WED MAY 21 2014
QUICK UPDATE TO BRING GRIDS IN LINE WITH LATEST TRENDS...OBS. ISSUED
A FLASH FLOOD WATCH EARLIER FOR SEVERAL HOURS FOR OUR SOUTHWESTERN
COUNTIES. COLD POOL BOUNDARY IS CURRENTLY SETTING UP ACROSS OUR
SOUTHWEST. SHORT WAVE IS PASSING THROUGH THE REGION AND MODELS
ADVERTISE A BRIEF PERIOD OF INCREASED H850 WINDS UP AGAINST AND OVER
THE COLD POOL BOUNDARY IN RESPONSE TO APPROACHING SHORT WAVE
DISTURBANCE. BASED ON UPSTREAM RAINFALL RATES AND TOTALS FROM EARLIER
THIS EVENING FELT IT PRUDENT TO ISSUE A WATCH FOR A FEW HOURS AS
SHOWERS AND THUNDERSTORMS WILL LIKELY REDEVELOP ALONG THE NW...SE
ORIENTED COLD POOL BOUNDARY DURING THE NEXT FEW HOURS. ONCE SHORT
WAVE HAS PASSED EAST OF OUR AREA H850 WINDS SHOULD SLACKEN AND THE
FLASH FLOOD THREAT SHOULD DIMINISH.
UPDATE ISSUED AT 750 PM EDT WED MAY 21 2014
DID A QUICK UPDATE TO FINE TUNE THE POP AND WX GRIDS FOCUSING A BIT
MORE ON THE WESTERN PORTION OF THE CWA ARRIVING SHORTLY AFTER 9 PM
AND RUNNING SOUTH BY 11 PM. ALSO TRIED TO CAPTURE SOME OF THE LATE
NIGHT COLD POOL IN THE T AND TD GRIDS USING THE NEWEST CONSSHORT
DATA. ALSO ADDED A STORM TOTAL QPF GRID AND SHIPPED THAT OUT TO THE
WEB. THESE UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 655 PM EDT WED MAY 21 2014
NOW THAT WE ARE UNDER A SEVERE THUNDERSTORM WATCH BOX UNTIL 2 AM EDT
HAVE UPDATED ALL THE GRIDS THROUGH THE NIGHT TO REFLECT THE SEVERE
THREATS AND TIME THE STORM CLUSTERS AS FORECASTED BY THE HRRR. DID
TEMPER THE PROGNOSIS FROM THAT MODEL WITH THE EXISTING GRIDS AND
ALSO THE 18Z NAM12. IT DOES LOOK LIKE COLD POOLS ARE DEVELOPING WITH
THE CURRENT CLUSTERS TO THE NORTH AND THIS SHOULD HELP DRIVE STRONG
TO SEVERE STORMS SOUTH INTO OUR CWA QUICKER. HAVE TIMED THE STORMS
INTO THE JACKSON AREA AROUND 9 PM WITH THEM ARRIVING AN HOUR OR SO ON
EITHER SIDE OF THAT TIME NORTHWEST AND SOUTHEAST OF THE OFFICE. KEPT
IN THE HEAVY RAIN POTENTIAL AND THE HRRR IS NOW SHOWING BETTER
TRAINING POTENTIAL FOR OUR WESTERN COUNTIES THROUGH THE NIGHT. LARGE
HAIL AND GUSTY WINDS ARE STILL THE MAIN THREATS...THOUGH. DO EXPECT
THE SEVERE MODE TO TRANSITION TO A MAINLY DAMAGING WINDS ONE OVER THE
NEXT FEW HOURS. THESE GRID UPDATES AND THE NEW WCN/ZFP/HWO HAVE BEEN
ISSUED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 350 PM EDT WED MAY 21 2014
18Z SFC ANALYSIS SHOWS LOW PRESSURE OVER THE GREAT LAKES WITH A COLD
FRONT EXTENDING SOUTHWEST THROUGH THE NORTHWEST OHIO VALLEY AND INTO
THE MIDDLE OF MISSOURI. SOUTHEAST OF THIS...PLENTY OF FUEL IS
BUILDING FOR CONVECTION IN THE FORM OF DEWPOINTS IN THE LOW TO MID
60S AND TEMPERATURES PUSHING 80 DEGREES. THIS HAS HELPED TO PRIME
EAST KENTUCKY FOR CONVECTION LATER IN THE EVENING AND THROUGH THE
NIGHT. A FEW ROGUE SHOWERS ARE POPPING UP AND DRIFTING EAST THROUGH
THE AREA THIS AFTERNOON...BUT THE MAIN SHOW LATER THIS EVENING WILL
BE ASSOCIATED WITH THE ONGOING STORMS IN OHIO AND INDIANA EITHER
DIRECTLY OR AS A RE-SPAWNED CLUSTER ON AN OUTFLOW BOUNDARY. ON
SATELLITE...THE HIGHER DEBRIS CLOUDS ARE STARTING TO CLEAR FROM THE
EARLIER CONVECTION TO THE NORTH. THIS SHOULD HELP GIVE A FINAL PUSH
TO THE INSTABILITY OVER THE NEXT SEVERAL HOURS...THOUGH LOWER CLOUDS
WILL REMAIN DUE TO THIS HUMID ENVIRONMENT. MEANWHILE...WINDS ARE FROM
THE SOUTHWEST TO WEST AT 10 TO 20 MPH WITH SOME GUSTS TO 25 MPH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH RIDGING RETREATING TO THE
SOUTH TONIGHT IN THE FACE OF A DECENTLY STRONG SHORTWAVE MOVING
THROUGH FAST NORTHWEST FLOW...CROSSING NORTHERN KENTUCKY. THIS FLOW
PATTERN REMAINS IN PLACE INTO THE DAY THURSDAY WITH JUST A SLIGHT
SHIFT TO THE SOUTHWEST WITH THE MID LEVEL ENERGY TRACK. HEIGHT FALLS
WILL ACCOMPANY THIS ADJUSTMENT THROUGH EAST KENTUCKY INTO FRIDAY
MORNING IN CONJUNCTION WITH A SHARPER TROUGH SWEEPING SOUTHEAST
THROUGH THE EASTERN GREAT LAKES. WITH THIS AGREEMENT HAVE MAINLY
FOLLOWED THE GENERAL DETAILS FROM THE CURRENT AND PAST FEW RUNS OF
THE HRRR ALONG WITH SOME NAM12 INFLUENCE.
SENSIBLE WEATHER WILL FEATURE A LIKELY STORMY NIGHT ACROSS THE AREA.
THE HEIGHT FALLS...ENERGY PERTURBANCES AT MID LEVELS...AND A SPEED
MAX AT 500MB KEEPS THE STAGE SET FOR CONVECTIVE REDEVELOPMENT THROUGH
THE NIGHT INTO THURSDAY. INCREASING PWS...TOWARD 1.5 INCHES...THROUGH
THE AREA WILL CONTRIBUTE TO A POTENTIAL FOR HEAVY TO EXCESSIVE
AMOUNTS OF RAIN TONIGHT....ESPECIALLY IF SOLID COLD POOLS DEVELOP
ALONG WITH TRAINING OF CELLS. HOWEVER...CONFIDENCE IN ANY EXACT
SCENARIO REMAINS LOW GIVEN THE DEVELOPING CONVECTION PATTERN AND THE
CHALLENGE OF PREDICTING SUBSEQUENT INITIATION OFF OF THE SOUTHWARD
MOVING OUTFLOW BOUNDARIES. A LACK OF A CAP AND LIS TO -6/CAPES TO
2000 J/KG WILL ALSO MEAN A GOOD POTENTIAL FOR SEVERE WEATHER WITH ANY
ORGANIZED STORMS THIS EVENING AND INTO THE OVERNIGHT...SHOULD PRIOR
CONVECTION NOT STABILIZE THE ENVIRONMENT. HAVE HIT THIS POTENTIAL
HARD IN THE GRIDS...ZONES...AND HWO. AFTER A MILD NIGHT...A BOUNDARY
SHOULD BE LAYING FROM NORTHWEST TO SOUTHEAST ACROSS EAST KENTUCKY
WITH STILL A POTENTIAL FOR STRONG STORMS ACROSS SOUTHWESTERN PARTS
OF THE AREA. HAVE CONTINUED THIS THREAT INTO THE AFTERNOON. THE
BOUNDARY SHOULD WEAKEN AND DRIFT FURTHER SOUTHEAST INTO THE NIGHT
WITH LESS OF A RISK FOR CONVECTION. COOLER TEMPS WILL BE FOUND
THURSDAY NIGHT OVER OUR NORTHEAST WITH MILDER AND MUGGIER CONDITIONS
SOUTHWEST.
USED THE BCCONSSHORT GRIDS AS A STARTING POINT FOR TEMPERATURES...
DEWPOINTS...AND WINDS THROUGH THE FIRST 24 HOURS AND THEN TACKED ON
THE BCCONSALL. MOST ADJUSTMENTS WHERE MADE FOR TERRAIN DIFFERENCES
TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP ON THE HIGH SIDE
OF ALL GUIDANCE...BUT CLOSEST TO THE HIGHER MET NUMBERS TONIGHT AND
THURSDAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 300 PM EDT WED MAY 21 2014
EXTENDED MODELS ARE IN REASONABLE AGREEMENT THROUGH THE PERIOD...BUT
AS USUAL THERE IS BETTER AGREEMENT WITH LARGE SCALE FEATURES THAN
WITH DETAILS. WE START WITH AN UPPER LEVEL DISTURBANCE THAT DROPS
SOUTHEAST THROUGH THE REGION FRIDAY...EFFECTIVELY JUMP STARING A
TEMPORARILY STALLED OUT SFC COLD FRONTAL BOUNDARY AND SWEEPING IT
OUT OF OUR AREA. THEREAFTER UPPER LEVEL RIDGING AND SFC HIGH
PRESSURE WILL BUILD OVER OUR AREA AND PROVIDE US WITH VERY PLEASANT
WEATHER FOR THE UPCOMING WEEKEND.
MODELS DIFFER MORE WITH RETURN FLOW REGIME EARLY NEXT WEEK. WARM
FRONTAL ZONE WILL MOVE BACK TO THE NORTH ACROSS THE AREA MONDAY AND
COULD PROVIDE SOME PRECIPITATION TO EASTERN KENTUCKY. THEREAFTER WE
FIND OURSELVES IN THE WARM SECTOR AND MORE SUMMER LIKE WEATHER UNTIL
THE POTENTIAL ARRIVAL OF A LOW PRESSURE SYSTEM THAT WILL SLOWLY
MEANDER ITS WAY OUT OF THE CENTRAL PLAINS. 0Z ECMWF WANTS TO BRING
THIS SLOW MOVING DISTURBANCE INTO THE HEART OF THE OHIO VALLEY BY
LATE THURSDAY INTO FRIDAY...JUST BEYOND THE FORECAST WINDOW. A MUCH
MORE INCONSISTENT GFS...AND MORE SPECIFICALLY THE 12Z RUN WANTS TO
TAKE THE DISTURBANCE TO THE GULF COAST...WHILE DEVELOPING A MUCH
STRONGER SYSTEM OVER THE OHIO VALLEY FROM ENERGY DROPPING OUT OF
CANADA DURING THAT SME TIME FRAME. PAST RUNS OF THE ECMWF HAVE SHOWN
A TENDENCY TO TAKE THE DISTURBANCE TO THE GULF COAST AS WELL...BUT
HAS NOT SHOWN ANY EVIDENCE OF SUCH A STRONG SYSTEM DROPPING OUT OF
CANADA.
FOR SENSIBLE WEATHER...ATMOSPHERE STABILIZES RAPIDLY EARLY FRIDAY
MORNING. SO ANY SHOWERS THAT MIGHT LINGER ACROSS THE AREA THURSDAY
NIGHT WILL COME TO AN END JUST AS QUICKLY EARLY FRIDAY MORNING. HIGH
PRESSURE AND A PLEASANTLY COOL AIR MASS OVER THE AREA WILL PROVIDE
GREAT WEATHER FOR THE WEEKEND. WEATHER WILL TURN MUGGY AND RELATIVELY
HOT EARLY NEXT WEEK AFTER A WARM FRONT PUNCHES ITS WAY ACROSS OUR
AREA TO THE NORTH. FOR NOW IT APPEARS THE THREAT OF SHOWERS AND
THUNDERSTORMS WILL INCREASE DAILY THROUGH THE REMAINDER OF THE
WEEK...BUT MUCH WILL DEPEND ON THE PATTERN THAT SETS UP AT THE END
OF THE FORECAST WINDOW AND BEYOND. THE ECMWF AND GFS BOTH ADVERTISE
UNSETTLED WEATHER OVER OUR AREA BY THE END OF THE WEEK BUT VIA
DIFFERENT MEANS TO THAT END. AT THIS POINT AND AFTER CONSIDERING THE
TIME OF YEAR THOUGHTS ARE THAT ANYTHING IS POSSIBLE BEYOND TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 810 PM EDT WED MAY 21 2014
CONDITIONS ARE CLINGING TO VFR THROUGH THE AREA...BUT THE CIGS DO
REMAIN NEAR MVFR IN THIS HUMID PRE-STORM ENVIRONMENT. CONVECTION...
STRONG TO SEVERE...IS ON TRACK TO PUSH SOUTH INTO THE FORECAST AREA
OVER THE NEXT SEVERAL HOURS. HAVE FORECASTED THE WORST CONDITIONS FOR
THE WESTERN PORTION OF THE AREA...LOZ AND SME. WHILE TO THE EAST...AT
JKL AND SJS...HAVE KEPT IT A BIT TAMER. EXPECT THE THREAT OF
THUNDERSTORMS AND LOWER CIGS TO LINGER THROUGH THE REMAINDER OF THE
AREA INTO THE MORNING THURSDAY...AND EARLY AFTERNOON TO THE SOUTHWEST.
HOWEVER... CONDITIONS WILL IMPROVE FROM NORTHEAST TO SOUTHWEST AS A
COLD FRONT RETREATS TO THE SOUTHWEST WITH TIME. KEPT THE RISK OF
THUNDER AND THE LOWER CIGS IN FOR SME THE LONGEST. WINDS WILL BE
OCCASIONALLY BREEZY FROM THE WEST SOUTHWEST THROUGH THE EVENING...BUT
WITH STORMS THE GUSTS COULD BE UP TO 40 KTS OR HIGHER IN THE
WEST...THOUGH CLOSER TO 30 KTS IN THE EAST. LIGHTER WEST WINDS...
OUTSIDE OF ANY STORMS...WILL FOLLOW FOR THE REST OF THE NIGHT AND
INTO THE DAY THURSDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 5 AM EDT THURSDAY FOR KYZ058-068-069-079-
080-083>087-111-114-116.
&&
$$
UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...RAY
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
810 PM EDT WED MAY 21 2014
.UPDATE...
ISSUED AT 750 PM EDT WED MAY 21 2014
DID A QUICK UPDATE TO FINE TUNE THE POP AND WX GRIDS FOCUSING A BIT
MORE ON THE WESTERN PORTION OF THE CWA ARRIVING SHORTLY AFTER 9 PM
AND RUNNING SOUTH BY 11 PM. ALSO TRIED TO CAPTURE SOME OF THE LATE
NIGHT COLD POOL IN THE T AND TD GRIDS USING THE NEWEST CONSSHORT
DATA. ALSO ADDED A STORM TOTAL QPF GRID AND SHIPPED THAT OUT TO THE
WEB. THESE UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 655 PM EDT WED MAY 21 2014
NOW THAT WE ARE UNDER A SEVERE THUNDERSTORM WATCH BOX UNTIL 2 AM EDT
HAVE UPDATED ALL THE GRIDS THROUGH THE NIGHT TO REFLECT THE SEVERE
THREATS AND TIME THE STORM CLUSTERS AS FORECASTED BY THE HRRR. DID
TEMPER THE PROGNOSIS FROM THAT MODEL WITH THE EXISTING GRIDS AND
ALSO THE 18Z NAM12. IT DOES LOOK LIKE COLD POOLS ARE DEVELOPING WITH
THE CURRENT CLUSTERS TO THE NORTH AND THIS SHOULD HELP DRIVE STRONG
TO SEVERE STORMS SOUTH INTO OUR CWA QUICKER. HAVE TIMED THE STORMS
INTO THE JACKSON AREA AROUND 9 PM WITH THEM ARRIVING AN HOUR OR SO ON
EITHER SIDE OF THAT TIME NORTHWEST AND SOUTHEAST OF THE OFFICE. KEPT
IN THE HEAVY RAIN POTENTIAL AND THE HRRR IS NOW SHOWING BETTER
TRAINING POTENTIAL FOR OUR WESTERN COUNTIES THROUGH THE NIGHT. LARGE
HAIL AND GUSTY WINDS ARE STILL THE MAIN THREATS...THOUGH. DO EXPECT
THE SEVERE MODE TO TRANSITION TO A MAINLY DAMAGING WINDS ONE OVER THE
NEXT FEW HOURS. THESE GRID UPDATES AND THE NEW WCN/ZFP/HWO HAVE BEEN
ISSUED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 350 PM EDT WED MAY 21 2014
18Z SFC ANALYSIS SHOWS LOW PRESSURE OVER THE GREAT LAKES WITH A COLD
FRONT EXTENDING SOUTHWEST THROUGH THE NORTHWEST OHIO VALLEY AND INTO
THE MIDDLE OF MISSOURI. SOUTHEAST OF THIS...PLENTY OF FUEL IS
BUILDING FOR CONVECTION IN THE FORM OF DEWPOINTS IN THE LOW TO MID
60S AND TEMPERATURES PUSHING 80 DEGREES. THIS HAS HELPED TO PRIME
EAST KENTUCKY FOR CONVECTION LATER IN THE EVENING AND THROUGH THE
NIGHT. A FEW ROGUE SHOWERS ARE POPPING UP AND DRIFTING EAST THROUGH
THE AREA THIS AFTERNOON...BUT THE MAIN SHOW LATER THIS EVENING WILL
BE ASSOCIATED WITH THE ONGOING STORMS IN OHIO AND INDIANA EITHER
DIRECTLY OR AS A RE-SPAWNED CLUSTER ON AN OUTFLOW BOUNDARY. ON
SATELLITE...THE HIGHER DEBRIS CLOUDS ARE STARTING TO CLEAR FROM THE
EARLIER CONVECTION TO THE NORTH. THIS SHOULD HELP GIVE A FINAL PUSH
TO THE INSTABILITY OVER THE NEXT SEVERAL HOURS...THOUGH LOWER CLOUDS
WILL REMAIN DUE TO THIS HUMID ENVIRONMENT. MEANWHILE...WINDS ARE FROM
THE SOUTHWEST TO WEST AT 10 TO 20 MPH WITH SOME GUSTS TO 25 MPH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH RIDGING RETREATING TO THE
SOUTH TONIGHT IN THE FACE OF A DECENTLY STRONG SHORTWAVE MOVING
THROUGH FAST NORTHWEST FLOW...CROSSING NORTHERN KENTUCKY. THIS FLOW
PATTERN REMAINS IN PLACE INTO THE DAY THURSDAY WITH JUST A SLIGHT
SHIFT TO THE SOUTHWEST WITH THE MID LEVEL ENERGY TRACK. HEIGHT FALLS
WILL ACCOMPANY THIS ADJUSTMENT THROUGH EAST KENTUCKY INTO FRIDAY
MORNING IN CONJUNCTION WITH A SHARPER TROUGH SWEEPING SOUTHEAST
THROUGH THE EASTERN GREAT LAKES. WITH THIS AGREEMENT HAVE MAINLY
FOLLOWED THE GENERAL DETAILS FROM THE CURRENT AND PAST FEW RUNS OF
THE HRRR ALONG WITH SOME NAM12 INFLUENCE.
SENSIBLE WEATHER WILL FEATURE A LIKELY STORMY NIGHT ACROSS THE AREA.
THE HEIGHT FALLS...ENERGY PERTURBANCES AT MID LEVELS...AND A SPEED
MAX AT 500MB KEEPS THE STAGE SET FOR CONVECTIVE REDEVELOPMENT THROUGH
THE NIGHT INTO THURSDAY. INCREASING PWS...TOWARD 1.5 INCHES...THROUGH
THE AREA WILL CONTRIBUTE TO A POTENTIAL FOR HEAVY TO EXCESSIVE
AMOUNTS OF RAIN TONIGHT....ESPECIALLY IF SOLID COLD POOLS DEVELOP
ALONG WITH TRAINING OF CELLS. HOWEVER...CONFIDENCE IN ANY EXACT
SCENARIO REMAINS LOW GIVEN THE DEVELOPING CONVECTION PATTERN AND THE
CHALLENGE OF PREDICTING SUBSEQUENT INITIATION OFF OF THE SOUTHWARD
MOVING OUTFLOW BOUNDARIES. A LACK OF A CAP AND LIS TO -6/CAPES TO
2000 J/KG WILL ALSO MEAN A GOOD POTENTIAL FOR SEVERE WEATHER WITH ANY
ORGANIZED STORMS THIS EVENING AND INTO THE OVERNIGHT...SHOULD PRIOR
CONVECTION NOT STABILIZE THE ENVIRONMENT. HAVE HIT THIS POTENTIAL
HARD IN THE GRIDS...ZONES...AND HWO. AFTER A MILD NIGHT...A BOUNDARY
SHOULD BE LAYING FROM NORTHWEST TO SOUTHEAST ACROSS EAST KENTUCKY
WITH STILL A POTENTIAL FOR STRONG STORMS ACROSS SOUTHWESTERN PARTS
OF THE AREA. HAVE CONTINUED THIS THREAT INTO THE AFTERNOON. THE
BOUNDARY SHOULD WEAKEN AND DRIFT FURTHER SOUTHEAST INTO THE NIGHT
WITH LESS OF A RISK FOR CONVECTION. COOLER TEMPS WILL BE FOUND
THURSDAY NIGHT OVER OUR NORTHEAST WITH MILDER AND MUGGIER CONDITIONS
SOUTHWEST.
USED THE BCCONSSHORT GRIDS AS A STARTING POINT FOR TEMPERATURES...
DEWPOINTS...AND WINDS THROUGH THE FIRST 24 HOURS AND THEN TACKED ON
THE BCCONSALL. MOST ADJUSTMENTS WHERE MADE FOR TERRAIN DIFFERENCES
TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP ON THE HIGH SIDE
OF ALL GUIDANCE...BUT CLOSEST TO THE HIGHER MET NUMBERS TONIGHT AND
THURSDAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 300 PM EDT WED MAY 21 2014
EXTENDED MODELS ARE IN REASONABLE AGREEMENT THROUGH THE PERIOD...BUT
AS USUAL THERE IS BETTER AGREEMENT WITH LARGE SCALE FEATURES THAN
WITH DETAILS. WE START WITH AN UPPER LEVEL DISTURBANCE THAT DROPS
SOUTHEAST THROUGH THE REGION FRIDAY...EFFECTIVELY JUMP STARING A
TEMPORARILY STALLED OUT SFC COLD FRONTAL BOUNDARY AND SWEEPING IT
OUT OF OUR AREA. THEREAFTER UPPER LEVEL RIDGING AND SFC HIGH
PRESSURE WILL BUILD OVER OUR AREA AND PROVIDE US WITH VERY PLEASANT
WEATHER FOR THE UPCOMING WEEKEND.
MODELS DIFFER MORE WITH RETURN FLOW REGIME EARLY NEXT WEEK. WARM
FRONTAL ZONE WILL MOVE BACK TO THE NORTH ACROSS THE AREA MONDAY AND
COULD PROVIDE SOME PRECIPITATION TO EASTERN KENTUCKY. THEREAFTER WE
FIND OURSELVES IN THE WARM SECTOR AND MORE SUMMER LIKE WEATHER UNTIL
THE POTENTIAL ARRIVAL OF A LOW PRESSURE SYSTEM THAT WILL SLOWLY
MEANDER ITS WAY OUT OF THE CENTRAL PLAINS. 0Z ECMWF WANTS TO BRING
THIS SLOW MOVING DISTURBANCE INTO THE HEART OF THE OHIO VALLEY BY
LATE THURSDAY INTO FRIDAY...JUST BEYOND THE FORECAST WINDOW. A MUCH
MORE INCONSISTENT GFS...AND MORE SPECIFICALLY THE 12Z RUN WANTS TO
TAKE THE DISTURBANCE TO THE GULF COAST...WHILE DEVELOPING A MUCH
STRONGER SYSTEM OVER THE OHIO VALLEY FROM ENERGY DROPPING OUT OF
CANADA DURING THAT SME TIME FRAME. PAST RUNS OF THE ECMWF HAVE SHOWN
A TENDENCY TO TAKE THE DISTURBANCE TO THE GULF COAST AS WELL...BUT
HAS NOT SHOWN ANY EVIDENCE OF SUCH A STRONG SYSTEM DROPPING OUT OF
CANADA.
FOR SENSIBLE WEATHER...ATMOSPHERE STABILIZES RAPIDLY EARLY FRIDAY
MORNING. SO ANY SHOWERS THAT MIGHT LINGER ACROSS THE AREA THURSDAY
NIGHT WILL COME TO AN END JUST AS QUICKLY EARLY FRIDAY MORNING. HIGH
PRESSURE AND A PLEASANTLY COOL AIR MASS OVER THE AREA WILL PROVIDE
GREAT WEATHER FOR THE WEEKEND. WEATHER WILL TURN MUGGY AND RELATIVELY
HOT EARLY NEXT WEEK AFTER A WARM FRONT PUNCHES ITS WAY ACROSS OUR
AREA TO THE NORTH. FOR NOW IT APPEARS THE THREAT OF SHOWERS AND
THUNDERSTORMS WILL INCREASE DAILY THROUGH THE REMAINDER OF THE
WEEK...BUT MUCH WILL DEPEND ON THE PATTERN THAT SETS UP AT THE END
OF THE FORECAST WINDOW AND BEYOND. THE ECMWF AND GFS BOTH ADVERTISE
UNSETTLED WEATHER OVER OUR AREA BY THE END OF THE WEEK BUT VIA
DIFFERENT MEANS TO THAT END. AT THIS POINT AND AFTER CONSIDERING THE
TIME OF YEAR THOUGHTS ARE THAT ANYTHING IS POSSIBLE BEYOND TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 810 PM EDT WED MAY 21 2014
CONDITIONS ARE CLINGING TO VFR THROUGH THE AREA...BUT THE CIGS DO
REMAIN NEAR MVFR IN THIS HUMID PRE-STORM ENVIRONMENT. CONVECTION...
STRONG TO SEVERE...IS ON TRACK TO PUSH SOUTH INTO THE FORECAST AREA
OVER THE NEXT SEVERAL HOURS. HAVE FORECASTED THE WORST CONDITIONS FOR
THE WESTERN PORTION OF THE AREA...LOZ AND SME. WHILE TO THE EAST...AT
JKL AND SJS...HAVE KEPT IT A BIT TAMER. EXPECT THE THREAT OF
THUNDERSTORMS AND LOWER CIGS TO LINGER THROUGH THE REMAINDER OF THE
AREA INTO THE MORNING THURSDAY...AND EARLY AFTERNOON TO THE SOUTHWEST.
HOWEVER... CONDITIONS WILL IMPROVE FROM NORTHEAST TO SOUTHWEST AS A
COLD FRONT RETREATS TO THE SOUTHWEST WITH TIME. KEPT THE RISK OF
THUNDER AND THE LOWER CIGS IN FOR SME THE LONGEST. WINDS WILL BE
OCCASIONALLY BREEZY FROM THE WEST SOUTHWEST THROUGH THE EVENING...BUT
WITH STORMS THE GUSTS COULD BE UP TO 40 KTS OR HIGHER IN THE
WEST...THOUGH CLOSER TO 30 KTS IN THE EAST. LIGHTER WEST WINDS...
OUTSIDE OF ANY STORMS...WILL FOLLOW FOR THE REST OF THE NIGHT AND
INTO THE DAY THURSDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...RAY
AVIATION...GREIF
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 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 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 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 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
NWS DULUTH MN
805 PM CDT WED MAY 21 2014
.UPDATE...
ISSUED AT 805 PM CDT WED MAY 21 2014
CLOUDS ARE HANGING TOUGH AND NOT EXPECTING ANY ADDITIONAL CLEARING
FROM WHAT HAS ALREADY OCCURRED THIS EVENING. WITH THIS CLOUD
COVER...HAVE BUMPED UP MIN TEMPS A FEW DEGREES AS WELL AS
DEWPOINTS. HAVE REMOVED THE RAIN MENTION FROM THE ARROWHEAD AS
WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 302 PM CDT WED MAY 21 2014
CLOUDS HAVE BEEN VERY SLOW TO DIMINISH OVER THE NORTHLAND TODAY
UNDER COOL NORTHWESTERLY FLOW ALOFT. THEY ARE STARTING TO THIN TO
OUR SOUTHWEST...AND THAT TREND WILL CONTINUE OVERNIGHT. WE DID
INCREASE CLOUDS THIS EVENING FOR MOST AREAS...FOLLOWING CLOSE TO
THE RAP LOW LEVEL MOISTURE FIELDS. THE LATEST RAP ALSO SHOWS
CLOUDS HANGING IN FOR MUCH OF THE NIGHT OVER THE NORTHEAST HALF TO
TWO THIRDS OF THE CWA. WE WILL MONITOR CLOUD TRENDS TONIGHT AND
WE MAY NEED TO BEEF UP CLOUDS AND ADJUST LOWS UP.
WE BUMPED UP CLOUDS A BIT ON THURSDAY AND WENT WITH PARTLY CLOUDY
SKIES. WE THINK THERE COULD BE CLOUDS AROUND EARLY AND WE SHOULD
DEVELOP SOME CU THROUGH THE DAY. AT THE SURFACE...HIGH PRESSURE
WILL BE OVERHEAD BUT TEMPS WILL STILL BE COOL ALOFT.
HIGH PRESSURE WILL CONTINUE TO IMPACT THE REGION AND PROVIDE DRY
CONDITIONS INTO FRIDAY. TEMPERATURES WILL WARM FROM THE SIXTIES
THURSDAY INTO THE SEVENTIES FOR MOST AREAS ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED MAY 21 2014
THE EXTENDED PERIOD FROM FRIDAY NIGHT THROUGH NEXT WEDNESDAY FINALLY
LOOKS TO BE A SUSTAINED PERIOD OF AT OR ABOVE NORMAL TEMPS ACROSS
MOST OF THE REGION. WHILE AREAS NEAR LAKE SUPERIOR WILL LIKELY SEE
RATHER ROBUST LAKE BREEZE FRONTS DURING THE MIDDAY TO EVENING HOURS
SAT-MON TIME FRAME..THE REMAINDER OF THE DULUTH CWA SHOULD SEE HIGH
TEMPS WELL INTO THE 70S..ALONG WITH DEWPOINTS REACHING INTO THE 60S
BY THE MON-WED TIME FRAME.
SURFACE AND MID LEVEL RIDGE AXIS SHOULD BE OVER THE CWA NEAR THE
BEGINNING OF THE PERIOD FRI NIGHT/SAT..BRINGING A COOL MORNING.
HOWEVER..RETURN SOUTH/SOUTHEAST FLOW SHOULD DEVELOP IN MOST AREAS BY
MIDDAY SAT..WITH BEST CHANCES FOR RAIN SHOWERS REMAINING TO OUR WEST
UNTIL LATER IN THE DAY. RATHER ROBUST DIFFERENTIAL HEATING SHOULD
RESULT IN A FAIRLY STRONG LK SUPERIOR LAKE BOUNDARY DURING THE
AFTERNOON..WITH HIGH TEMPS OCCURRING LATE MORNING TO EARLY AFTERNOON
IN THE FAVORED LAKE BREEZE LOCATIONS. GIVEN THAT LOW LEVEL FLOW WILL
LIKELY STILL HAVE SOME EASTERLY COMPONENT..THERE SEEMS TO BE
POTENTIAL FOR ANY LAKE BREEZE BOUNDARY TO PENETRATE RATHER FAR
INLAND BY LATE AFTERNOON SATURDAY..WITH SOME COOLING EFFECT POSSIBLY
NOTED AS FAR WEST AS THE GRAND RAPIDS/IRON RANGE/INTERIOR ARROWHEAD
AREAS BY EVENING.
CHANCES FOR SHOWERS/TSTORMS WILL INCREASE FROM WEST TO EAST LATE SAT
INTO MONDAY AS NORTHERN STREAM WAVE PUSHES A WEAK FRONT INTO THE NE
MN AREA..BEFORE THE FRONT STALLS AND/OR WASHES OUT EARLY NEXT WEEK.
THE LARGE SOUTHERN STREAM UPPER LOW TRAVERSING THE PLAINS STATES TO
OUR SOUTH DURING THIS TIME AND PRECIPITATION/DEEP CONVECTION
ASSOCIATED WITH IT MAY ACT TO LESSEN THE NORTHWARD LOW LEVEL
MOISTURE TRANSPORT. HOWEVER..SUFFICIENT MOISTURE IS EXPECTED TO BE
IN PLACE TO SUPPORT SOME SHOWERS/STORMS IN VICINITY OF THE LINGERING
BOUNDARY FROM SAT NIGHT INTO MONDAY. AT THIS TIME..IT APPEARS THAT
INSTABILITY AND ESPECIALLY WIND SHEAR/FLOW WILL BE TOO WEAK TO
SUPPORT MUCH IN THE WAY OF ANY SEVERE WEATHER POTENTIAL. AGAIN..WE
EXPECT A LK SUPERIOR LAKE BREEZE FRONT TO DEVELOP SUN-MON AS
WELL..RESULTING IN LATE MORNING/EARLY AFTERNOON HIGH TEMPS IN AREAS
NEAR THE LAKE.
BY MID WEEK..A RATHER SIGNIFICANT LARGE SCALE PATTERN SHIFT TO A
PACNW UPPER TROF AND BROAD WSW MID LEVEL FLOW FROM THE GREAT BASIN
TO MANITOBA/NW ONTARIO SHOULD RESULT IN THE BUILDING OF A LOW LEVEL
THERMAL RIDGE FROM THE DAKOTAS INTO NW MINNESOTA. WHILE THE BEST
FLOW AND SHEAR AS WELL AS INSTABILITY AXIS IS EXPECTED TO REMAIN TO
OUR WEST BASED ON CURRENT GUIDANCE..THERE WILL STILL BE POTENTIAL FOR
SOME ELEVATED STORMS WITHIN THE LOW LEVEL WARM/MOIST ADVECTIVE ZONE
JUST DOWNSTREAM FROM THE MAIN UPPER LEVEL RIDGE AXIS ACROSS THE
DULUTH CWA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 617 PM CDT WED MAY 21 2014
CLOUDS WILL HANG ON THROUGH THE NIGHT FOR MUCH OF THE AREA WITH
MVFR CIGS AT INL/HIB/DLH. HYR WILL MAINTAIN THE VFR CIGS. BRD WILL
BE CLOUD FREE. GUSTY SFC WINDS SHOULD DIMINISH AROUND 02Z. EXPECT
INL/HIB/DLH TO IMPROVE TO VFR BY 16Z/22.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 43 64 43 69 / 0 0 0 0
INL 41 63 40 73 / 0 0 0 10
BRD 42 69 43 75 / 0 0 0 10
HYR 42 65 39 73 / 0 0 0 0
ASX 43 63 39 68 / 0 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...GSF
SHORT TERM...MELDE
LONG TERM...MILLER
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
651 PM CDT WED MAY 21 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED MAY 21 2014
A BENIGN SHORT TERM PERIOD IS EXPECTED AS MID LEVEL RIDGING BUILDS
OVER THE AREA AHEAD OF A SOUTHWESTERN CONUS CLOSED LOW. SKIES
WILL CLEAR TONIGHT AND ALLOW TEMPERATURES TO COOL INTO THE
40S...WHICH IS A BIT COOLER THAN CLIMATOLOGICAL NORMALS. SLIGHTLY
WARMER TEMPERATURES WILL BE FOUND ON THURSDAY...ALTHOUGH H85
TEMPERATURES WILL STILL BE IN THE SINGLE DIGITS WITH NORTHERLY
FLOW...SO READINGS WILL AGAIN BE SLIGHTLY BELOW NORMAL FOR LATE
MAY. HIGHS WILL MODERATE INTO THE MID 60S /WI/ TO LOWER 70S /WC
MN/.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 21 2014
THURSDAY NIGHT THROUGH FRIDAY NIGHT...HIGH PRES WILL BE OVHD AT
THE START OF THIS PERIOD...MAKING FOR CLEAR AND COOL CONDS GOING
INTO LATE MAY. THE AREA OF HIGH PRES WILL SLOWLY SHIFT AWAY TO THE
E...RESULTING IN SLY WINDS AT THE SFC THAT WILL CONTINUE INTO FRI
NIGHT. ALOFT...NW FLOW WILL GIVE WAY TO A RIDGE AXIS MOVG INTO WRN
MN BY FRI NIGHT. THE COMBINATION OF THE SFC HIGH AND DRY NW FLOW
ALOFT WILL KEEP AN ORGANIZING STORM SYSTEM OVER THE ROCKIES FROM
SHIFTING INTO THE CENTRAL CONUS...BUT THIS STORM SYSTEM WILL BE A
LARGER CONCERN GOING INTO THE WEEKEND AND EARLY NEXT WEEK.
SATURDAY THROUGH WEDNESDAY...A RIDGE AXIS ALOFT WILL CROSS OVER
THE UPR MISS RIVER VALLEY DURG THE DAY ON SAT...FOLLOWED BY
PRONOUNCED SW FLOW WITH SEVERAL SHTWV DISTURBANCES RIDING WITHIN
THE FLOW THRU MON NIGHT. IN ADDITION...A LONGWAVE TROF WILL SHIFT
E ALONG THE INTERNATIONAL BORDER FROM THE PACIFIC COAST...SLOWLY
APPROACHING THE REGION. AT THE SFC...A DRAWN OUT CDFNT WILL SLOWLY
SHIFT EWD ALONG THE NRN TIER STATES...EVENTUALLY TRANSITIONING TO
A WMFNT ASSOCIATED WITH A DEVELOPING AREA OF LOW PRES OVER THE
CO/KS AREA. WHAT THIS TRANSLATES TO IS NOT ONLY WARMING
TEMPERATURES BEING IN THE WARM SECTOR OF THIS LARGE SYSTEM BUT
ALSO A NOTICEABLE INCRS IN MOISTURE /DEWPOINTS/ DUE TO A LARGE
PLUME OF MOISTURE BEING ADVECTED INTO THIS REGION FROM THE GULF OF
MEXICO. INSTABILITY WILL INCRS WHILE CAPPING DISINTEGRATES...
SETTING THE STAGE FOR OCCASIONAL SHWRS/TSTMS STARTING SAT NIGHT
AND LASTING UNTIL AT LEAST TUE...DEPENDING ON HOW QUICKLY THIS
SYSTEM EJECTS TO THE E AND A SECOND SYSTEM ARRIVES ON ITS HEELS.
JETTING IS WEAK WITH THE SAT-TUE SYSTEM...WHILE INSTABILITY IS
MODEST...SO AM NOT LOOKING FOR MUCH IN THE WAY OF SEVERE WEATHER
BUT THE ISOLD STRONG-SEVERE STORM CANNOT BE RULED OUT. HIGHS ARE
EXPECTED TO CLIMB INTO THE UPR 70S TO NEAR 80 WHILE LOWS DROP TO
THE UPR 50S TO LWR 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 651 PM CDT WED MAY 21 2014
BASICALLY ONLY ONE CONCERN FOR THIS CYCLE AND THAT IS THE
POTENTIAL FOR MVFR CEILINGS TO DEVELOP/SPREAD INTO KRNH AND KEAU
FROM THE NORTH TOWARDS DAYBREAK. SYNOPTIC SCALE MODELS SHOW THE RH
POTENTIAL ALONG WITH THE RAP 0.5KM CONDENSATION PRESSURE DEFICITS
LOWERING SIGNIFICANTLY. LAMP GUIDANCE AS WELL HINTING AT MVFR
CEILINGS. NOT TOTALLY SOLD ON THE IDEA WITH SURFACE HIGH PRESSURE
BODILY OVERHEAD BY THURSDAY MORNING. THERE WILL BE SOME SCT-BKN VFR
CLOUDS IN THESE AREAS DURING THE DAY ON THURSDAY AS THE CU RULE
REMAINS NEGATIVE. NW WINDS DIMINISHING UNDER 10 KNOTS EARLY THIS
EVENING AND BECOMING MORE NORTHERLY. N TO NW WINDS ON THURSDAY
FROM 6-10 KNOTS.
KMSP...VFR THROUGH THE PERIOD WITH CLR-SCT CONDITIONS. NW WIND
NEAR 10 KNOTS EARLY THIS EVENING DIMINISHING TO 6 KNOTS BY
SUNSET. NW WIND 7-9 KNOTS ON THURSDAY.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE 5-10 KTS.
SAT...VFR. WINDS SE 12 KTS.
SUN...VFR. CHC MVFR AND -SHRA/TS. WINDS S 12-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...JPC
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS DULUTH MN
617 PM CDT WED MAY 21 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 302 PM CDT WED MAY 21 2014
CLOUDS HAVE BEEN VERY SLOW TO DIMINISH OVER THE NORTHLAND TODAY
UNDER COOL NORTHWESTERLY FLOW ALOFT. THEY ARE STARTING TO THIN TO
OUR SOUTHWEST...AND THAT TREND WILL CONTINUE OVERNIGHT. WE DID
INCREASE CLOUDS THIS EVENING FOR MOST AREAS...FOLLOWING CLOSE TO
THE RAP LOW LEVEL MOISTURE FIELDS. THE LATEST RAP ALSO SHOWS
CLOUDS HANGING IN FOR MUCH OF THE NIGHT OVER THE NORTHEAST HALF TO
TWO THIRDS OF THE CWA. WE WILL MONITOR CLOUD TRENDS TONIGHT AND
WE MAY NEED TO BEEF UP CLOUDS AND ADJUST LOWS UP.
WE BUMPED UP CLOUDS A BIT ON THURSDAY AND WENT WITH PARTLY CLOUDY
SKIES. WE THINK THERE COULD BE CLOUDS AROUND EARLY AND WE SHOULD
DEVELOP SOME CU THROUGH THE DAY. AT THE SURFACE...HIGH PRESSURE
WILL BE OVERHEAD BUT TEMPS WILL STILL BE COOL ALOFT.
HIGH PRESSURE WILL CONTINUE TO IMPACT THE REGION AND PROVIDE DRY
CONDITIONS INTO FRIDAY. TEMPERATURES WILL WARM FROM THE SIXTIES
THURSDAY INTO THE SEVENTIES FOR MOST AREAS ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED MAY 21 2014
THE EXTENDED PERIOD FROM FRIDAY NIGHT THROUGH NEXT WEDNESDAY FINALLY
LOOKS TO BE A SUSTAINED PERIOD OF AT OR ABOVE NORMAL TEMPS ACROSS
MOST OF THE REGION. WHILE AREAS NEAR LAKE SUPERIOR WILL LIKELY SEE
RATHER ROBUST LAKE BREEZE FRONTS DURING THE MIDDAY TO EVENING HOURS
SAT-MON TIME FRAME..THE REMAINDER OF THE DULUTH CWA SHOULD SEE HIGH
TEMPS WELL INTO THE 70S..ALONG WITH DEWPOINTS REACHING INTO THE 60S
BY THE MON-WED TIME FRAME.
SURFACE AND MID LEVEL RIDGE AXIS SHOULD BE OVER THE CWA NEAR THE
BEGINNING OF THE PERIOD FRI NIGHT/SAT..BRINGING A COOL MORNING.
HOWEVER..RETURN SOUTH/SOUTHEAST FLOW SHOULD DEVELOP IN MOST AREAS BY
MIDDAY SAT..WITH BEST CHANCES FOR RAIN SHOWERS REMAINING TO OUR WEST
UNTIL LATER IN THE DAY. RATHER ROBUST DIFFERENTIAL HEATING SHOULD
RESULT IN A FAIRLY STRONG LK SUPERIOR LAKE BOUNDARY DURING THE
AFTERNOON..WITH HIGH TEMPS OCCURRING LATE MORNING TO EARLY AFTERNOON
IN THE FAVORED LAKE BREEZE LOCATIONS. GIVEN THAT LOW LEVEL FLOW WILL
LIKELY STILL HAVE SOME EASTERLY COMPONENT..THERE SEEMS TO BE
POTENTIAL FOR ANY LAKE BREEZE BOUNDARY TO PENETRATE RATHER FAR
INLAND BY LATE AFTERNOON SATURDAY..WITH SOME COOLING EFFECT POSSIBLY
NOTED AS FAR WEST AS THE GRAND RAPIDS/IRON RANGE/INTERIOR ARROWHEAD
AREAS BY EVENING.
CHANCES FOR SHOWERS/TSTORMS WILL INCREASE FROM WEST TO EAST LATE SAT
INTO MONDAY AS NORTHERN STREAM WAVE PUSHES A WEAK FRONT INTO THE NE
MN AREA..BEFORE THE FRONT STALLS AND/OR WASHES OUT EARLY NEXT WEEK.
THE LARGE SOUTHERN STREAM UPPER LOW TRAVERSING THE PLAINS STATES TO
OUR SOUTH DURING THIS TIME AND PRECIPITATION/DEEP CONVECTION
ASSOCIATED WITH IT MAY ACT TO LESSEN THE NORTHWARD LOW LEVEL
MOISTURE TRANSPORT. HOWEVER..SUFFICIENT MOISTURE IS EXPECTED TO BE
IN PLACE TO SUPPORT SOME SHOWERS/STORMS IN VICINITY OF THE LINGERING
BOUNDARY FROM SAT NIGHT INTO MONDAY. AT THIS TIME..IT APPEARS THAT
INSTABILITY AND ESPECIALLY WIND SHEAR/FLOW WILL BE TOO WEAK TO
SUPPORT MUCH IN THE WAY OF ANY SEVERE WEATHER POTENTIAL. AGAIN..WE
EXPECT A LK SUPERIOR LAKE BREEZE FRONT TO DEVELOP SUN-MON AS
WELL..RESULTING IN LATE MORNING/EARLY AFTERNOON HIGH TEMPS IN AREAS
NEAR THE LAKE.
BY MID WEEK..A RATHER SIGNIFICANT LARGE SCALE PATTERN SHIFT TO A
PACNW UPPER TROF AND BROAD WSW MID LEVEL FLOW FROM THE GREAT BASIN
TO MANITOBA/NW ONTARIO SHOULD RESULT IN THE BUILDING OF A LOW LEVEL
THERMAL RIDGE FROM THE DAKOTAS INTO NW MINNESOTA. WHILE THE BEST
FLOW AND SHEAR AS WELL AS INSTABILITY AXIS IS EXPECTED TO REMAIN TO
OUR WEST BASED ON CURRENT GUIDANCE..THERE WILL STILL BE POTENTIAL FOR
SOME ELEVATED STORMS WITHIN THE LOW LEVEL WARM/MOIST ADVECTIVE ZONE
JUST DOWNSTREAM FROM THE MAIN UPPER LEVEL RIDGE AXIS ACROSS THE
DULUTH CWA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 617 PM CDT WED MAY 21 2014
CLOUDS WILL HANG ON THROUGH THE NIGHT FOR MUCH OF THE AREA WITH
MVFR CIGS AT INL/HIB/DLH. HYR WILL MAINTAIN THE VFR CIGS. BRD WILL
BE CLOUD FREE. GUSTY SFC WINDS SHOULD DIMINISH AROUND 02Z. EXPECT
INL/HIB/DLH TO IMPROVE TO VFR BY 16Z/22.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 42 64 43 69 / 10 0 0 0
INL 40 63 40 73 / 10 0 0 10
BRD 41 69 43 75 / 0 0 0 10
HYR 41 65 39 73 / 10 0 0 0
ASX 42 63 39 68 / 10 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM...MILLER
AVIATION...GSF
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
640 PM CDT Wed May 21 2014
.SHORT TERM: (Through Late Tonight)
Issued at 1256 PM CDT Wed May 21 2014
Cold front extended from just north of UIN southwest through MCI.
This front will move southward through our forecast area tonight, and
should extend from west central MO southeast through southern IL by
12z Thursday. The cap should break late this afternoon with
scattered convection developing along this front. The HRRR model
has most of the convection across northeast MO and west central IL
early this evening, then shifts it southward with most of the
convection from around COU east through the St Louis metro area to
Vandalia and Salem IL by midnight. Some of these storms may be
severe due to very unstable conditions late this afternoon and this
evening with CAPEs of 2000-3000 J/Kg and surface LI values as low as
-10 south of the cold front. Low-mid level shear will also be
relatively strong with 500 mb wind speeds of up to 50 kts due to a
500 mb wind max moving through the Great Lakes region.
GKS
.LONG TERM: (Thursday through Next Wednesday)
Issued at 340 PM CDT Wed May 21 2014
The cold front will continue to sag slowly southward as a surface
ridge shifts eastward from the northern Plains into the Great Lakes
region. At least scattered convection is expected along and just
behind this front as weak shortwaves move east southeastward through
our area over the mid-upper level ridge centered over the Gulf Coast
states. The best coverage of convection should be across central
and southeast MO Thursday and Thursday night as the front becomes
more nw to se oriented. The ECMWF model appears to be a little too
far north with its qpf from Thursday afternoon into Friday morning.
Cooler and drier air will advect into the region behind the cold
front, particularly across northeast MO and west central IL.
The mid-upper level low now over NV will move slowly through the
southwest US. Weak shortwaves will eject northeastward from this
feature and bring more convection mainly to the western portion of
our forecast area Saturday and Saturday night with the upper level
ridge along with the surface ridge centered over the Great Lakes and
Ohio Valley regions keeping the eastern portion of our forecast area
dry. The mid-upper level low will eventually move into the Plains
by Monday. The models have varying solutions after this with the
ECMWF model moving it into MO by Tuesday, while the GFS model
weakens it and has it passing south of our area. With this model
uncertainty will just include chance pops for early next week,
although there may be more widespread showers/storms for Monday
night and Tuesday. Always difficult to forecast the exact path,
strength and speed of upper level lows coming out of the southwest
US.
GKS
&&
.AVIATION: (For the 00z TAFs through 00z Thursday Evening)
Issued at 640 PM CDT Wed May 21 2014
First round of thunderstorms have moved away from the St. Louis
metro TAF sites, though new thunderstorms are now developing near
KIRK which may affect KUIN through 01Z and may affect the St.
Louis metro TAF sites through 03Z. Conditions in the heavier cores
may have IFR visibilities and ceilings. A isolated severe
thunderstorms are also possible this evening with large hail and
strong wind gusts.
Surface cold front currently over northern Missouri and southern
Illinois will move south across the area this evening which will
end the threat of the thunderstorms late evening. The rest of the
TAF period is expected to be dry and VFR with winds veering out of
the northeast behind the front.
Specifics for KSTL:
The first round of thunderstorms have moved well east of the
area, though a cold front will move south through the TAF site
late this evening bringing scattered thunderstorms to the area.
Have maintained a VCTS through 03Z based on this threat.
Additional storms have developed in the last 30 minutes near
Kirksville along the front. Once the front moves through, expect
mainly dry and VFR conditions with winds veering out of the north
to northeast.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
629 PM CDT Wed May 21 2014
.SHORT TERM...(This Evening through Thursday Night)
Issued at 305 PM CDT WED MAY 21 2014
The focus through the period continues to be on thunderstorms
chances. For this afternoon the frontal boundary currently slowly
moving south across portions of the NRN CWA should serve as the
focus for isolated to scattered storms. Dprog/Dt of the HRRR paints
a narrow zone of storms along the front forming by 5 to 6 pm in our
CWA, then they move east and clear the CWA by around 9 or 10 pm.
Latest ACARS soundings out of KMCI depict the CAP slowly eroding so
confidence is rather high we should see a few storms along the
front. Given the large CAPE and modest shear profiles large hail
and damaging winds will be the main threats.
Late overnight tonight a large complex of storms may work into the
CWA from the west/southwest. At this time the better chances of
seeing storms appears to favor the WRN and NRN areas of the CWA.
The complex of storms should be weakening as they move in, thus the
overnight SVR potential is rather low.
Tomorrow most of the CWA will be north of the surface front so high
temps should be back down to near normal... mid to upper 70s with
mid 80s across our far SRN zones. Precip wise is a tough call depending
on how long any overnight activity lingers into the daylight morning
hours, residual cloud debris and degree of instability. So for now
just have low chance pops through tomorrow into tomorrow evening
given a lack upper level forcing.
.LONG TERM...(Friday through Wednesday)
Issued at 305 PM CDT WED MAY 21 2014
A rather messy short to medium range forecast through the Memorial
Day holiday and into much of next week. Why? The development of
the cutoff low across the southwestern United States that will
slowly crawl eastward into early next week. This low is expected to
pull increasing amounts of low-mid level moisture northward into the
Plains which will interact with a stalled frontal boundary in the
region.
By Friday morning, precipitation chances will increase briefly as a
secondary shortwave drops through the Great Lakes and a brief window
of warm advection commences overnight. This upper trough will push surface
high pressure into the region, and force the stalled front well
south of the area, potentially forcing precip south and east of the
CWA Friday afternoon and evening.
It`s hard to get too specific on forecast details through this
weekend and into Monday due to shortwave timing issues. The weekend
shouldn`t be a washout, but we`ll have to carry scattered PoP
wording through Monday.
Medium range models are all over the place in the eventual track of
the upper low through the area through Thursday. ECMWF/GEM produces
fairly widespread rains for Monday and Tuesday with a northern track,
GFS dives the ejecting low too far south to produce widespread rains,
but more scattered activity. Ensemble approach provides little
benefit, with a substantial spread in solutions. For now, have to
continue to include PoPs through much of the extended.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 629 PM CDT WED MAY 21 2014
VFR conds will prevail through the evening hours as any convective
activity will remain east of the terminals. The main concern will
come after midnight as a mid level shortwave moves into the area.
Thunderstorm are forecast to blossom across southern Kansas tonight and
move northeastward into the area. These storms are forecast to
affect the terminals between 08Z-12Z however cigs will remain VFR
between 3-4kft with vsbys being reduced to 5SM in heavier showers.
Have kept a VCTS group in the TAF between 08Z-12Z due to the
differences in timing amongst models and because thunderstorms will
be in a decaying phase by the time they move into the area. Otherwise
conditions will remain VFR tomorrow with scattered-broken cu around
5kft. Winds will be like and vrb tonight with a stationary front in
the VC of the terminals. Winds will pick up from the east tomorrow
morning between 5-10kts.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Pietrycha
LONG TERM...Dux
AVIATION...73
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 HASTINGS NE
1101 PM CDT WED MAY 21 2014
.MESOSCALE DISCUSSION...
ISSUED AT 1101 PM CDT WED MAY 21 2014
A RATHER SUBSTANTIAL ENHANCED SHORT-TERM FCST /ESTF/ UPDATE HAS
BEEN PUBLISHED. ANVIL CLOUDS HAVE OVERSPREAD THE ENTIRE FCST AREA
AND THIS HAS SLOWED THE FALL IN TEMPS. FCST HOURLY TEMPS WERE
RUNNING TOO COOL. POPS/WX HAVE ALSO BEEN UPDATED.
WE CONTINUE TO MONITOR A SMALL MCS MOVING NE FROM WRN KS. THE
1049 PM SWOMCD WAS REVIEWED AND TRENDS ARE BEING MONITORED FOR A
NEW SVR TSTM WATCH. THIS CLUSTER OF STORMS HAS PRODUCED MULTIPLE
REPORTS OF 60-71 MPH WINDS WITH SEVERAL DAMAGING WIND SIGNATURES
ON RADAR.
AS IT CROSSES THE BORDER INTO NEB WE ANTICIPATE A RAPID DEMISE AS
IT WILL BE MOVING INTO A CONSIDERABLY LESS FAVORABLE ENVIRONMENT
PER THE LATEST MESO ANALYSIS. THE AIR OVER SRN NEB IS DRIER AND
MORE STABLE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 310 PM CDT WED MAY 21 2014
SHOWERS AND THUNDERSTORMS HAVE ALREADY DEVELOPED THIS AFTERNOON
ACROSS THE HIGH PLAINS AND ALONG THE FRONTAL BOUNDARY TO OUR
SOUTHWEST. WITH PLENTY OF INSTABILITY TO WORK WITH...ESPECIALLY
ACROSS MUCH OF NORTH CENTRAL KANSAS...EXPECT ADDITIONAL SHOWERS
AND THUNDERSTORMS TO DEVELOP AS THE UPPER LEVEL WAVE ACROSS
NORTHERN NEW MEXICO LIFTS INTO THE CENTRAL PLAINS THIS EVENING AND
OVERNIGHT. EXPECT THE POSSIBILITY FOR A FEW STRONG TO SEVERE
STORMS TO DEVELOP ESPECIALLY ACROSS OUR SOUTHERN COUNTIES...AS
THERE IS A SHARP DECREASE IN BOTH INSTABILITY AND SHEAR AS YOU
WORK FURTHER NORTH. SPC MESOANALYSIS PAGE SHOWS THIS NICELY...AND
NOT SURPRISED THAT THE SLIGHT RISK FOR SEVERE STORMS WAS SHIFTED
A BIT CLOSER TO THE STATE LINE WITH THE LATEST UPDATE. THAT
SAID...CANNOT COMPLETELY RULE OUT A STRONG STORM SOUTH OF I80 AND
NORTH OF THE STATE LINE OVERNIGHT AS THE STORMS SPREAD
NORTH...BUT BEST POTENTIAL FOR SEVERE WEATHER IS DEFINITELY
FURTHER SOUTH ACROSS NORTH CENTRAL KANSAS.
WHILE MODEL GUIDANCE IS STILL HIT AND MISS WITH ACTIVITY
OVERNIGHT...LATEST NAM/RAP/HRRR ALL INDICATE AT LEAST SCATTERED
ACTIVITY...SO CONFIDENCE IS INCREASING THAT MOST AREAS WILL SEE
SOME ACTIVITY BY DAYBREAK THURSDAY. THEN AS WE TRANSITION INTO THE
DAYTIME HOURS...THERE MAY BE A BRIEF LULL IN ACTIVITY...BUT YET
ANOTHER UPPER LEVEL DISTURBANCE IS EXPECTED BY AFTERNOON...AND
KEPT THE POTENTIAL FOR THUNDERSTORMS ACROSS THE ENTIRE AREA
THROUGH THE DAYTIME HOURS. WITH INCREASED CLOUD COVER AND SOME
SHOWERS AROUND...EXPECT TEMPERATURES TO BE A FEW DEGREES COOLER
ACROSS THE AREA ON THURSDAY...GENERALLY IN THE MID TO UPPER 70S
ACROSS THE NORTH...AND LOWER 80S ACROSS NORTH CENTRAL KANSAS. ONCE
AGAIN...COULD SEE A STRONG THUNDERSTORM ON THURSDAY...BUT BETTER
SHEAR AND INSTABILITY IS EXPECTED TO BE JUST WEST OF OUR FORECAST
AREA AT THIS TIME.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT WED MAY 21 2014
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS NEARLY
EVERY PERIOD AND TEMPERATURES.
AN UPPER LEVEL LOW IN THE SOUTHERN ROCKIES WILL MOVE FROM THE
ROCKIES INTO THE PLAINS THROUGH TUESDAY. WHILE THE UPPER LOW IS IN
THE ROCKIES...THERE WILL BE SEVERAL WAVES THAT MOVE INTO THE AREA
THROUGH SATURDAY. EACH OF THE WAVES HAS THE POTENTIAL FOR PRODUCING
SOME SHOWERS AND THUNDERSTORMS. IT CERTAINLY WILL NOT BE RAINING ALL
OF THE TIME...BUT AS EACH WAVE MOVES THROUGH THERE IS SOME
POTENTIAL. THROUGH THE END OF THE WEEK...THE BEST CHANCES WILL BE
LIKELY BE DURING THE AFTERNOONS NEAR A NEARLY STATIONARY FRONT
ACROSS KANSAS. THEN DURING THE NIGHT TIME THUNDERSTORMS FROM THE
HIGH PLAINS WILL MOVE INTO THE AREA.
INTO THE WEEKEND THE UPPER LOW MOVES OUT OF THE ROCKIES AND THE
STATIONARY FRONT SINKS TO THE SOUTH AND WEAKENS. THERE IS STILL
PLENTY OF MOISTURE AROUND AND THUNDERSTORM CHANCES WILL CONTINUE FOR
THE WEEKEND. FOR MONDAY AND TUESDAY THE UPPER LOW WEAKENS A LITTLE
BUT THE TROUGH IS ACROSS THE CENTRAL PLAINS. WILL CONTINUE THE
THUNDERSTORM CHANCES...BUT BY TUESDAY THE PRECIPITATION WILL FINALLY
START TO MOVE EAST OF THE AREA. WITH THE TROUGH TO THE EAST...WILL
LEAVE DRY CONDITIONS ACROSS THE AREA TUESDAY NIGHT INTO WEDNESDAY.
TEMPERATURES WILL BE FAIRLY STEADY THROUGH THE PERIOD WITH UPPER 70S
TO LOWER 80S FOR HIGHS AND AROUND 60 FOR LOWS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 628 PM CDT WED MAY 21 2014
THE CHALLENGE WITH THIS AVIATION FORECAST IS JUST WHAT RISK IS
THERE FOR SHOWERS/ISOLATED THUNDERSTORMS LATE TONIGHT. SHORT
TERM HRRR MODEL CONTINUES TO SUGGEST WHATS LEFT OF EASTERN
COLORADO CONVECTION WILL TEAM WITH SOME MORE OVERNIGHT DEVELOPING
AND SLIP INTO KGRI AROUND 08Z OR SO. CONFIDENCE IS A LITTLE IFFY
GIVEN DRY AIR IN PLACE AT KGRI...AND BETTER MOISTURE AND WHAT
INSTABILITY THERE IS...IS SOUTH INTO CENTRAL KANSAS. HOWEVER...
PERSISTENCE OF THE HRRR MAKES KEEPING AT LEAST THE THUNDERSTORM
RISK IN THE VICINITY OVERNIGHT. ASIDE FROM THAT...WINDS REMAIN
STEADILY FROM AN EASTERLY COMPONENT...AND CEILINGS IN THE VFR
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
MESOSCALE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...JCB
AVIATION...NOAA/NWS/MORITZ
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
636 PM CDT WED MAY 21 2014
.SYNOPSIS...
ISSUED AT 322 PM CDT WED MAY 21 2014
A FAIRLY STAGNANT UPPER LEVEL PATTERN WAS NOTED ACROSS
THE LOWER 48 THIS MORNING. WITH THE EXCEPTION OF FLAGSTAFF AZ...NO
UA SITES HAD HT FALLS OR RISES IN EXCESS OF 50 METERS. THE MAIN
FEATURES OF NOTE ACROSS THE LOWER 48 WERE HIGH PRESSURE OVER THE
MISSISSIPPI DELTA...A STRONG SHORTWAVE OFF THE COAST OF MAINE...AND
A CLOSED LOW OVER NEVADA. A WEAK JET STREAK AROUND 50 KTS WAS NOTED
FROM NRN AZ INTO WESTERN COLORADO. A COUPLE OF WEAK SHORTWAVES WERE
NOTED EARLY THIS AFTERNOON ALONG THE WESTERN SLOPES OF
COLORADO...AND OVER EASTERN NEW MEXICO. THESE TWO DISTURBANCES HAVE
LED TO INCREASED CLOUD COVER OVER WESTERN COLORADO...WYOMING...AS
WELL AS EASTERN NEW MEXICO AND THE TX PANHANDLE. AT THE
SURFACE...HIGH PRESSURE HAS PUSHED INTO THE DAKOTAS AND NORTHERN
NEBRASKA THIS AFTERNOON...FORCING A FRONTAL BOUNDARY INTO THE TEXAS
PANHANDLE. THIS BOUNDARY THEN WINDS TO THE WEST NORTHWEST ALONG THE
FRONT RANGE OF COLORADO AND WYOMING. WITH EASTERLY AND NORTHEASTERLY
WINDS...UNDER CLEAR TO PARTLY CLOUDY SKIES...2 PM CDT TEMPERATURES
RANGED FROM 65 AT AINSWORTH...TO 75 AT IMPERIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 322 PM CDT WED MAY 21 2014
WEAK PV ANOMALY MOVING NWD ALONG THE FRONT RANGE OF CO PER WV
IMAGERY SHOULD CONTINUE TO GENERATE SFC PRESSURE FALLS IN THE LEE OF
THE PALMER DIVIDE AND ENHANCE EXISTING UPSLOPE FLOW TO INITIATE TSRA
ALONG THE HIGHER TERRAIN INITIALLY...WITH ORGANIZED CONVECTIVE
MOVEMENT EXPECTED TO BE NORTHEASTWARD INTO WESTERN AND SW NEB. SHORT
RANGE MODEL FCST SOUNDINGS INDICATE SOME REMAINING...THOUGH
ELEVATED...INSTABILITY OVERNIGHT. HOWEVER MOISTURE IS NOT OVERLY
IMPRESSIVE FURTHER NORTHEAST INTO CENTAL NEBR SINCE NRLY/NERLY FLOW
AT THE SFC ADVECTING ONLY MID TO UPPER 40S DEW POINTS. IN THE
ABSENCE OF A WELL DEFINED LLJ CONVECTION WILL HAVE A DIFFICULT TIME
BEING SUSTAINED INTO CENTRAL NEBR...MUCH LIKE LAST FEW NIGHTS.
HOWEVER...SINCE ORGANIZED CONVECTION WILL LIKELY BE MORE WIDESPREAD
IT MAY HAVE BETTER POTENTIAL. SHORT RANGE MODELS CURRENTLY ARE IN
DISAGREEMENT WITH THIS. HRRR ENSEMBLE UPDRAFT HELICITY SUGGESTS
ORGANIZATION OF INDIVIDUAL UPDRAFTS WOULD WEAKEN AS ANY REMAINING
STORMS MOVE INTO SW NEB. HARD TO ASSESS POTENTIAL FOR SVR...MODELS
SOUNDINGS SHOW SOME CAPE IN THE LOWER RANGE OF THE HAIL GROWTH
REGION...STILL BETTER POPS ARE INCLUDED TONIGHT MOST AREAS THAN PREV
NIGHTS.
WOULD EXPECT A SIMILAR SCENARIO THURSDAY MORNING AS WITH LAST COUPLE
OF MORNINGS IN THAT CONVECTIVE DEBRIS WILL REMAIN ACROSS SOME
PORTIONS OF THE CWA...THOUGH PINPOINTING WHERE IS DIFFICULT.
THEREFORE POPS INCLUDED PRIMARILY WHERE ELEVATED INSTABILITY
RESIDES. UPPER LOW OVER THE SOUTHWEST MOVES LITTLE BUT PIVOTS TO
BECOME SLIGHTLY NEGATIVELY TILTED THURS AFTERNOON. AS A RESULT WINDS
SHOULD BECOME MORE SOUTHEASTERLY AND ADVECT BETTER MOISTURE BACK
INTO THE AREA. FEEL MORE ORGANIZED CONVECTION THURSDAY SHOULD AGAIN
ENTER WESTERN NEB AFTER 00Z FRI. HIGHS WILL BE TEMPERED SOME BY
CLOUD COVER EARLY...BUT SHOULD RECOVER IN THE AFTERNOON MUCH LIKE
TODAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 322 PM CDT WED MAY 21 2014
FOR THURSDAY NIGHT THROUGH SATURDAY...PRECIPITATION CHANCES CONTINUE
TO BE THE MAIN FORECASTING CHALLENGE IN THE MID RANGE PERIODS. LIKE
THIS AFTERNOON...THUNDERSTORMS ARE EXPECTED TO BE ONGOING BY
THURSDAY EVENING OVER NERN COLORADO AND NWRN KS INVOF OF A STALLED
OUT FRONTAL BOUNDARY. WEAK SOUTHERLY AND SSWRLY STEERING WINDS WILL
LIFT THIS ACTIVITY NORTH INTO WESTERN NEBRASKA THURSDAY EVENING. AS
HAS BEEN THE CASE OVER THE PAST COUPLE OF NIGHTS...THIS ACTIVITY HAS
WEAKENED SUBSTANTIALLY AS IT MOVES INTO THE FORECAST AREA FROM THE
WEST AND SOUTHWEST. HOWEVER...TOMORROW NIGHT INTO FRIDAY...LOW LEVEL
WINDS WILL SHIFT MORE TO THE SOUTHEAST AS SURFACE HIGH PRESSURE
LIFTS INTO THE UPPER MISSISSIPPI VALLEY THIS SHIFT IN THE WIND
DIRECTION WILL SERVE TWO PURPOSES...A INCREASE LOW LEVEL
MOISTURE-BRINGING DEW POINTS BACK INTO THE 50S AND B...LEAD TO A 20
TO 30 KT LOW LEVEL JET THURSDAY NIGHT...WHICH WILL HELP TO SUSTAIN
CONVECTION INTO THE LATE NIGHT HOURS. WITH THE FLOW BEING FAIRLY
WEAK IN THE MID LEVELS AND DEEP MID LAYER INSTABILITY BEING FAIRLY
MEAGER...DECIDED TO LEAVE POPS IN THE 30 TO 50 PERCENT RANGE AS
COVERAGE IS EXPECTED TO REMAIN SCATTERED. ON FRIDAY...THE FRONTAL
BOUNDARY WILL LIFT NORTH INTO SOUTHWESTERN AND WESTERN
NEBRASKA...ALLOWING SHOWERS AND THUNDERSTORMS TO LINGER DURING THE
DAYTIME HOURS. CAPPING ON FRIDAY IS WEAK PER THE LATEST NAM AND GFS
SOLNS...SO AFTERNOON HEATING DURING THE DAYTIME HOURS...WILL QUICKLY
LEAD TO ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT. IN
ADDITION...FCST QPF`S ARE EXPECTED TO BE THE HIGHEST FRIDAY/FRIDAY
NIGHT...GIVEN THE EXPECTED WEAK STEERING WINDS AND PWATS OF 1.25 TO
1.50 INCHES. WITH RESPECT TO SEVERE POTENTIAL FRIDAY...AT THIS
TIME...THE SEVERE THREAT FOR FRIDAY APPEARS TO BE MARGINAL GIVEN THE
WEAK MID LEVEL FLOW...ALONG WITH LITTLE OR NO CAP...WHICH WILL
PRODUCE COMPETING UPDRAFTS AND DISORGANIZED CLUSTERS OF STORMS. ON
SATURDAY...THE FRONTAL BOUNDARY WILL LIFT EAST INTO CENTRAL PORTIONS
OF THE FORECAST AREA...FORCED BY THE APPROACH OF THE UPPER LEVEL LOW
AND TROUGH...WHICH WILL REACH THE FOUR CORNERS BY 00Z SUNDAY. THOUGH
PCPN CHANCES REMAIN POSSIBLE ACROSS THE ENTIRE FORECAST AREA...THE
HIGHEST POPS SATURDAY AND SATURDAY NIGHT WILL BE CARRIED ALONG AND
NORTH OF THE FRONT...IMPACTING MAINLY NORTHERN AND EASTERN PORTIONS
OF THE FORECAST AREA.
SUNDAY THROUGH WEDNESDAY...THE UPPER LEVEL LOW WILL BEGIN TO FILL ON
SUNDAY AS IT LIFTS EAST INTO THE SRN PLAINS. PCPN CHANCES WILL
LINGER SUNDAY INTO MONDAY...BEFORE THE SYSTEM EXITS THE SOUTHERN
PLAINS INTO THE ARKLATEX. DRIER AND WARMER CONDITIONS ARE EXPECTED
TUESDAY INTO WEDNESDAY AS A POSITIVELY TILTED RIDGE EXTENDS FROM THE
DESERT SOUTHWEST INTO NRN MINNESOTA. HIGHS WILL RETURN TO THE LOWER
80S FROM THE MIDDLE 70S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 635 PM CDT WED MAY 21 2014
FOR THE 00Z KLBF AND KVTN TAFS...MAIN FORECAST CONCERN IS WHETHER
THE CONVECTION CURRENTLY MOVING EAST ACROSS THE HIGH PLAINS OF
EASTERN COLORADO WILL IMPACT AREA TAF SITES OVERNIGHT. CONVECTION
ALLOWING MODELS SUCH AS THE RAP13 AND HRRR CONTINUE TO ADVERTISE THIS
LINE OF STORMS MOVING INTO FAR SOUTHWEST NEBRASKA AFTER 02Z THIS
EVENING...BUT WEAKEN SOMEWHAT AS THEY ENCOUNTER A STABILIZING LOWER
TROPOSPHERE. ANOTHER LINE OF STORMS IS SHOWN TO FORM SHORTLY
THEREAFTER ACROSS FAR SOUTHERN NEBRASKA AS A LOW LEVEL JET
INTENSIFIES AND WORKS ON A BOUNDARY PARKED ACROSS NORTHERN KANSAS.
IT IS CONCEIVABLE THAT EITHER CONVECTIVE LINES COULD IMPACT THE KLBF
TERMINAL AFTER 05Z THIS EVENING. FOR THIS WILL KEEP A MENTION OF
-TSRA IN THE FORECAST FOR KLBF LATE THIS EVENING. ACROSS NORTHERN
NEBRASKA...RAIN CHANCES ARE MUCH MORE CONDITIONAL...THUS REMOVED THE
PROB30 GROUP FOR THIS EVENING. -TSRA CHANCES INCREASE ONCE AGAIN
LATE IN THE TAF PERIOD FRIDAY...FAVORING MAINLY TAF SITES ALONG AND
WEST OF HIGHWAY 83.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
633 PM CDT WED MAY 21 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 310 PM CDT WED MAY 21 2014
SHOWERS AND THUNDERSTORMS HAVE ALREADY DEVELOPED THIS AFTERNOON
ACROSS THE HIGH PLAINS AND ALONG THE FRONTAL BOUNDARY TO OUR
SOUTHWEST. WITH PLENTY OF INSTABILITY TO WORK WITH...ESPECIALLY
ACROSS MUCH OF NORTH CENTRAL KANSAS...EXPECT ADDITIONAL SHOWERS
AND THUNDERSTORMS TO DEVELOP AS THE UPPER LEVEL WAVE ACROSS
NORTHERN NEW MEXICO LIFTS INTO THE CENTRAL PLAINS THIS EVENING AND
OVERNIGHT. EXPECT THE POSSIBILITY FOR A FEW STRONG TO SEVERE
STORMS TO DEVELOP ESPECIALLY ACROSS OUR SOUTHERN COUNTIES...AS
THERE IS A SHARP DECREASE IN BOTH INSTABILITY AND SHEAR AS YOU
WORK FURTHER NORTH. SPC MESOANALYSIS PAGE SHOWS THIS NICELY...AND
NOT SURPRISED THAT THE SLIGHT RISK FOR SEVERE STORMS WAS SHIFTED
A BIT CLOSER TO THE STATE LINE WITH THE LATEST UPDATE. THAT
SAID...CANNOT COMPLETELY RULE OUT A STRONG STORM SOUTH OF I80 AND
NORTH OF THE STATE LINE OVERNIGHT AS THE STORMS SPREAD
NORTH...BUT BEST POTENTIAL FOR SEVERE WEATHER IS DEFINITELY
FURTHER SOUTH ACROSS NORTH CENTRAL KANSAS.
WHILE MODEL GUIDANCE IS STILL HIT AND MISS WITH ACTIVITY
OVERNIGHT...LATEST NAM/RAP/HRRR ALL INDICATE AT LEAST SCATTERED
ACTIVITY...SO CONFIDENCE IS INCREASING THAT MOST AREAS WILL SEE
SOME ACTIVITY BY DAYBREAK THURSDAY. THEN AS WE TRANSITION INTO THE
DAYTIME HOURS...THERE MAY BE A BRIEF LULL IN ACTIVITY...BUT YET
ANOTHER UPPER LEVEL DISTURBANCE IS EXPECTED BY AFTERNOON...AND
KEPT THE POTENTIAL FOR THUNDERSTORMS ACROSS THE ENTIRE AREA
THROUGH THE DAYTIME HOURS. WITH INCREASED CLOUD COVER AND SOME
SHOWERS AROUND...EXPECT TEMPERATURES TO BE A FEW DEGREES COOLER
ACROSS THE AREA ON THURSDAY...GENERALLY IN THE MID TO UPPER 70S
ACROSS THE NORTH...AND LOWER 80S ACROSS NORTH CENTRAL KANSAS. ONCE
AGAIN...COULD SEE A STRONG THUNDERSTORM ON THURSDAY...BUT BETTER
SHEAR AND INSTABILITY IS EXPECTED TO BE JUST WEST OF OUR FORECAST
AREA AT THIS TIME.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT WED MAY 21 2014
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS NEARLY
EVERY PERIOD AND TEMPERATURES.
AN UPPER LEVEL LOW IN THE SOUTHERN ROCKIES WILL MOVE FROM THE
ROCKIES INTO THE PLAINS THROUGH TUESDAY. WHILE THE UPPER LOW IS IN
THE ROCKIES...THERE WILL BE SEVERAL WAVES THAT MOVE INTO THE AREA
THROUGH SATURDAY. EACH OF THE WAVES HAS THE POTENTIAL FOR PRODUCING
SOME SHOWERS AND THUNDERSTORMS. IT CERTAINLY WILL NOT BE RAINING ALL
OF THE TIME...BUT AS EACH WAVE MOVES THROUGH THERE IS SOME
POTENTIAL. THROUGH THE END OF THE WEEK...THE BEST CHANCES WILL BE
LIKELY BE DURING THE AFTERNOONS NEAR A NEARLY STATIONARY FRONT
ACROSS KANSAS. THEN DURING THE NIGHT TIME THUNDERSTORMS FROM THE
HIGH PLAINS WILL MOVE INTO THE AREA.
INTO THE WEEKEND THE UPPER LOW MOVES OUT OF THE ROCKIES AND THE
STATIONARY FRONT SINKS TO THE SOUTH AND WEAKENS. THERE IS STILL
PLENTY OF MOISTURE AROUND AND THUNDERSTORM CHANCES WILL CONTINUE FOR
THE WEEKEND. FOR MONDAY AND TUESDAY THE UPPER LOW WEAKENS A LITTLE
BUT THE TROUGH IS ACROSS THE CENTRAL PLAINS. WILL CONTINUE THE
THUNDERSTORM CHANCES...BUT BY TUESDAY THE PRECIPITATION WILL FINALLY
START TO MOVE EAST OF THE AREA. WITH THE TROUGH TO THE EAST...WILL
LEAVE DRY CONDITIONS ACROSS THE AREA TUESDAY NIGHT INTO WEDNESDAY.
TEMPERATURES WILL BE FAIRLY STEADY THROUGH THE PERIOD WITH UPPER 70S
TO LOWER 80S FOR HIGHS AND AROUND 60 FOR LOWS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 628 PM CDT WED MAY 21 2014
THE CHALLENGE WITH THIS AVIATION FORECAST IS JUST WHAT RISK IS
THERE FOR SHOWERS/ISOLATED THUNDERSTORMS LATE TONIGHT. SHORT
TERM HRRR MODEL CONTINUES TO SUGGEST WHATS LEFT OF EASTERN
COLORADO CONVECTION WILL TEAM WITH SOME MORE OVERNIGHT DEVELOPING
AND SLIP INTO KGRI AROUND 08Z OR SO. CONFIDENCE IS A LITTLE IFFY
GIVEN DRY AIR IN PLACE AT KGRI...AND BETTER MOISTURE AND WHAT
INSTABILITY THERE IS...IS SOUTH INTO CENTRAL KANSAS. HOWEVER...
PERSISTENCE OF THE HRRR MAKES KEEPING AT LEAST THE THUNDERSTORM
RISK IN THE VICINITY OVERNIGHT. ASIDE FROM THAT...WINDS REMAIN
STEADILY FROM AN EASTERLY COMPONENT...AND CEILINGS IN THE VFR
CATEGORY THUS KEEPING MOST AVIATION PROBLEMS ON A LIMITED SCALE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ROSSI
LONG TERM...JCB
AVIATION...NOAA/NWS/MORITZ
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 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 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 LAS VEGAS NV
625 PM PDT WED MAY 21 2014
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL CIRCULATE OVER SOUTHERN
NEVADA AND SURROUNDING AREAS THROUGH FRIDAY PRODUCING ISOLATED TO
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. THE SYSTEM WILL FINALLY
MOVE AWAY TO THE EAST SATURDAY...WITH RAIN CHANCES DIMINISHING AND
TEMPERATURES QUICKLY CLIMBING OVER THE HOLIDAY WEEKEND.
&&
.UPDATE...A BIT MORE CLOUD COVER THAN EXPECTED HAD DEVELOPED OVER
PORTIONS OF CLARK AND SAN BERNARDINO COUNTY EARLY THIS EVENING. GFS
MODEL INDICATES MUCH OF THIS CLOUD COVER PERSISTING AT LEAST THROUGH
THE EVENING AND PERHAPS OVERNIGHT. I UPDATED THE SKY COVER GRIDS TO
INCREASE CLOUD COVER IN SOME AREAS FOR TONIGHT. RECENT SHOWER AND
THUNDERSTORM ACTIVITY/COVERAGE LOOKS TO BE ABOUT AS FORECAST SO NO
CHANGES TO POP AND WX FORECAST AT THIS TIME. -HARRISON-
&&
.PREV DISCUSSION...
330 PM PDT WED MAY 21 2014
.SHORT TERM...THROUGH FRIDAY NIGHT...THE CIRCULATION CENTER OF THE
CUTOFF LOW HAS REMAINED OVER CENTRAL NYE COUNTY THROUGH THE DAY BUT
IT WILL QUICKLY DIVE DOWN OVER SOUTHERN CALIFORNIA TONIGHT. THIS IS
DUE TO ENERGY ROTATING DOWN THE WEST SIDE OF THE LOW WHICH WAS
AIDING IN PRODUCING A BAND OF CONSOLIDATED SHOWERS OVER THE
SOUTHWEST PART OF INYO COUNTY. THE 18Z NAM AND HRRR INDICATE THESE
SHOWERS WILL PUSH DOWN THROUGH NORTHWEST SAN BERNARDINO COUNTY THIS
EVENING AND A THUNDERSTORM OR TWO WILL ALSO BE POSSIBLE. SHOWERS
WILL DIMINISH AFTER 06Z AS THE LOW CENTER MOVES TOWARD THE SOUTHERN
CALIFORNIA COAST. MODELS ARE IN GOOD AGREEMENT THAT THE SYSTEM WILL
STRADDLE THE MEXICO BORDER AS IT SLOWLY CHURNS TOWARD THE EAST
THROUGH FRIDAY NIGHT. THIS SCENARIO WILL KEEP THE LIMITED MOISTURE
WITH THE SYSTEM MAINLY WEST OF LAS VEGAS THURSDAY. AS THE LOW CENTER
MOVES INTO SOUTHWEST ARIZONA FRIDAY AND FRIDAY NIGHT...WRAP AROUND
MOISTURE WILL BE PULLED DOWN THROUGH SOUTHERN NEVADA AND NORTHWEST
ARIZONA. SHOWERS SHOULD BE CONFINED PRIMARILY TO THE MOUNTAINS.
.LONG TERM...SATURDAY THROUGH TUESDAY.
MEMORIAL DAY WEEKEND IS LOOKING PRETTY TOASTY WITH MODEL CONSENSUS
SHOWING HIGH PRESSURE MOVING OVER THE AREA DURING THE WEEKEND.
YESTERDAY, MODELS WERE FORECASTING A TROUGH MOVING INTO THE WEST
EARLY NEXT WEEK BRINGING SLIGHTLY COOLER TEMPERATURES FOR MEMORIAL
DAY. NOW THE TROUGH AND ANY ASSOCIATED SHORTWAVE ENERGY IS FORECAST
TO STAY WELL NORTH OF THE AREA AND HAVE LITTLE TO NO IMPACT ON
TEMPERATURES. THUS, HIGHS SHOULD TOP OUT A FEW DEGREES ABOVE NORMAL
SATURDAY THEN WARM ANOTHER 3-5 DEGREES SUNDAY AND HOLD STEADY MONDAY
AND POSSIBLY INTO TUESDAY. IT`S A DISTINCT POSSIBILITY THAT
TEMPERATURES COULD AGAIN REACH OR EVEN EXCEED 100 DEGREES IN LAS
VEGAS ON SUNDAY AND MEMORIAL DAY, BUT FOR NOW, DECIDED TO KEEP THEM
IN THE UPPER 90S TO SEE IF MODEL SOLUTIONS MAINTAIN CONTINUITY OR
REVERT BACK TO A STRONGER PACIFIC TROUGH MOVING INTO THE WEST. &&
.AVIATION...FOR MCCARRAN...SOUTHEAST TO EAST WINDS MAY EXCEED 10
KNOTS THROUGH EARLY EVENING BEFORE BECOMING LIGHT AND VARIABLE 1-2
HOURS AFTER SUNSET AND EARLY THURSDAY. AN EASTERLY WIND COMPONENT
CAN BE EXPECTED THURSDAY AFTERNOON. SCT CLOUDS WITH BASES 10-12 KFT
WILL REMAIN AROUND THE AREA WITH SHOWERS POSSIBLE OVER THE SPRING
MOUNTAINS AND SHEEP RANGE THROUGH EARLY THIS EVENING THEN AGAIN
THURSDAY AS A LOW PRESSURE SYSTEM CIRCULATES AROUND SOUTHERN
CALIFORNIA AND SOUTHERN NEVADA.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...A LOW PRESSURE
SYSTEM WILL MOVE FROM CENTRAL NEVADA TO SOUTHERN CALIFORNIA TONIGHT
AND THURSDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS CAN BE EXPECTED OVER AREAS TO THE NORTH AND WEST OF
LAS VEGAS THROUGH THURSDAY. CLOUD BASES WILL GENERALLY BE AROUND
8-10 KFT MSL AND WILL LEAD TO PARTIAL MOUNTAIN OBSCURATION OVER THE
SOUTHERN SIERRA.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
SHORT TERM/AVIATION...ADAIR
LONG TERM...SALMEN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1030 PM EDT WED MAY 21 2014
.SYNOPSIS...
AFTER A PLEASANTLY WARM AND DRY WEDNESDAY...AN UPPER-LEVEL
DISTURBANCE OVER THE NORTHERN GREAT LAKES WILL HAVE AN INCREASING
INFLUENCE ON OUR WEATHER AS IT SHIFTS SOUTHEASTWARD ACROSS NEW YORK
AND NEW ENGLAND THURSDAY AND FRIDAY. CLOUDS WILL BE ON THE INCREASE
OVERNIGHT TONIGHT...WITH A CHANCE FOR RAIN SHOWERS TOWARD
MORNING...MAINLY ACROSS NORTHERN NEW YORK AND INTO SOUTH-CENTRAL
VERMONT. SHOWERS WILL BECOME MORE WIDESPREAD ACROSS THE REGION WITH
DAYTIME HEATING ON THURSDAY. LOOK FOR MOSTLY CLOUDY SKIES WITH
NUMEROUS SLOW-MOVING SHOWERS...AND A SLIGHT CHANCE OF AN AFTERNOON
THUNDERSTORM. INTERVALS OF RAIN WILL CONTINUE THURSDAY NIGHT INTO
FRIDAY...WITH THE FOCUS FOR THE MOST WIDESPREAD ACTIVITY EXPECTED
ACROSS NORTHERN NEW YORK. DRIER WEATHER WILL RETURN FOR THE WEEKEND
AS THE UPPER LEVEL LOW SHIFTS SOUTHEAST OF NEW ENGLAND AND A WEAK
RIDGE OF HIGH PRESSURE BUILDS IN ACROSS THE ST. LAWRENCE VALLEY.
&&
.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
AS OF 1030 PM EDT WEDNESDAY...ADDL SMALL ADJUSTMENTS TO POPS ACROSS
THE AREA OVERNIGHT...CONFINING ANY ISOLD/WIDELY SCT ACTIVITY TO
OUR SOUTHWESTERN COUNTIES AND LEAVING REMAINDER OF FORECAST AREA
GENERALLY DRY OVERNIGHT. CAN`T COMPLETELY RULE OUT ISOLD THUNDER
SOUTHWEST PER LATEST RAP SHOWALTER PROGS...BUT OMITTED MENTION DUE
TO EXPECTED PAUCITY OF COVERAGE. TEMPS/TD/SKY/WINDS REMAIN ON
TRACK SO NO OTHER CHANGES NEEDED AT THIS POINT. HAVE A GREAT
NIGHT. PRIOR DISCUSSIONS FOLLOW...
PRIOR DISCUSSION...
A FEW UPDATES AS WE PROGRESS INTO THE EVENING HOURS...MAINLY TO
INTRODUCE A LOW CHANCE OF SHOWERS FOR THE WESTERN SLOPES OF THE
DACKS INTO THE SLV AND TO INCREASE CLOUD COVER ACROSS THE AREA
SOMEWHAT. CURRENT RADAR SHOWING ISOLD TO WIDELY SCT SHOWERS HAVE
DEVELOPED ACROSS PORTIONS OF THE SLV EARLY THIS EVENING. SOME
HEAVIER T-STORM ACTIVITY ALSO EVIDENT FURTHER WEST ACROSS SOUTHERN
ONTARIO INVOF PEMBROKE/RENFREW WHERE LOCAL WARNINGS ARE IN EFFECT
FROM ENV CANADA. NOT EXPECTING ANY STORM ACTIVITY TO REACH OUR NRN
NY COUNTIES THIS EVENING AS AIRMASS REMAINS QUITE STABLE OVER OUR
AREA. HOWEVER...A MID LEVEL SHEAR ZONE HAS MATERIALIZED ACROSS
THESE AREAS PER LATEST RAP PROGS...AND WITH AT LEAST SOME SUPPORT
FROM ~90KT UPPER LEVEL JET TO THE IMMEDIATE SOUTHWEST...I LIKE THE
MOST RECENT RAP/HRRR PROGS SHOWING CONTINUED SCT SHOWER ACTIVITY
IN THESE AREAS OVERNIGHT AS MID LEVEL HEIGHTS SLOWLY FALL. MORE
LIMITED ACTIVITY NORTH AND EAST OF A KMSS-KBTV-KVSF LINE UNTIL
LATER TONIGHT AS THESE AREAS INITIALLY FURTHER REMOVED FROM BETTER
MOISTURE/UPPER LEVEL SUPPORT. DID OPT TO BLEND POPS FROM 06Z
ONWARD INTO CURRENT FORECAST AT 12Z...BUT IF CURRENT TRENDS
CONTINUE MAY HAVE TO ADJUST POPS FURTHER DOWNWARD NORTH AND EAST
LATER TONIGHT. REST OF FORECAST IN GOOD SHAPE AT THIS POINT.
PRIOR DISCUSSION...
NARROW SFC RIDGE CENTERED ACROSS THE NORTH COUNTRY RESULTING IN A
PLEASANT AFTN WITH JUST SCATTERED FAIR WEATHER CUMULUS CLOUDS
DOTTING THE HIGHER TERRAIN PER AFTN VISIBLE IMAGERY. 2-M TEMPS
REACHED THE MID 70S (77F AT KBTV AT 1830Z) AS EXPECTED
AREAWIDE...WITH DELIGHTFULLY LOW DEWPOINTS IN THE 30S TO LOWER
40S. WINDS HAVE ALSO BEEN RATHER LIGHT IN VCNTY OF PREVAILING SFC
ANTICYCLONE. PLEASANT CONDITIONS WILL CONTINUE THROUGH THIS
EVENING WITH TEMPERATURES FALLING THROUGH THE 60S WITH ONSET OF
DIURNAL COOLING CYCLE.
SOME GRADUAL CHANGES WILL OCCUR LATE TONIGHT. THE 850MB FRONTAL ZONE
ACROSS SRN MI/NRN OH/PA...WHICH HAS BEEN THE FOCUS FOR SHOWER AND
TSTM ACTIVITY OVER THE PAST 12-24 HRS...WILL SLOWLY LIFT NEWD...BUT
IS ALSO EXPECTED TO SLOWLY WEAKEN. AT THE SAME TIME...MID-LEVEL
HEIGHT FALLS ARE EXPECTED ACROSS NY/VT AS CLOSED UPR LOW OVER THE
NRN GREAT LAKES BEGINS TO SHIFT INTO SERN ONTARIO OVERNIGHT. IT
SHOULD REMAIN DRY THRU MIDNIGHT ALL SECTIONS...BUT RESULT OF THE
FRONTAL ZONE AND HEIGHT FALLS SUGGESTS WE SHOULD BEGIN TO SEE SOME
ISOLD/SCT SHOWER ACTIVITY DEVELOP ACROSS OUR NRN NY COUNTIES SEWD
INTO RUTLAND COUNTY AFTER MIDNIGHT...AND ESPECIALLY AFTER 09Z. AIR
MASS WILL REMAIN QUITE DRY FURTHER NORTH AND EAST...SO ACTIVITY
SHOULD REMAIN SOUTH AND WEST OF THE CHAMPLAIN VALLEY THRU DAYBREAK
BASED ON CURRENT INDICATIONS. LOOK FOR A GRADUALLY INCREASE IN MID
AND UPPER LEVELS CLOUDS FROM THE CHAMPLAIN VALLEY NORTH AND EASTWARD
LATE.
STAYED CLOSE TO MOS CONSENSUS FOR OVERNIGHT LOWS. WITH INCREASE IN
CLOUDS LATE...WILL SEE TEMPS A BIT WARMER THAN THE PREVIOUS COUPLE
OF NIGHTS. LOWS GENERALLY IN THE UPR 40S TO LOWER 50S...EXCEPT MID
40S FOR THE NORMALLY COOLER VALLEYS WITHIN THE NRN ADIRONDACK REGION
AND ACROSS FAR NERN VT. A LIGHT S-SE WIND WILL DEVELOP OVERNIGHT AS
SFC RIDGE SLIDES EWD INTO MAINE.
&&
.SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 253 PM EDT WEDNESDAY...UNSETTLED WX CONDITIONS EXPECTED THRU MUCH
OF THE PERIOD. LOW-MID LEVEL LOW PRESSURE SYSTEM ROTATES SEWD
FROM SERN ONTARIO INTO THE ST. LAWRENCE VALLEY LATE THURSDAY
AFTN...AND THEN SLIDES SLOWLY SEWD ACROSS CENTRAL NEW YORK STATE
(JUST SOUTH OF THE ADIRONDACKS) AND SRN NEW ENGLAND THURSDAY NIGHT
THROUGH FRIDAY. MODELS CONTINUE TO INDICATE BEST FOCUS FOR
WIDESPREAD RAIN SHOWERS WILL BE ALONG AND JUST NORTH OF THE
700-500MB VORT TRACK...WHICH LINES UP ACROSS OUR NRN ADIRONDACK
ZONES AND INTO S-CENTRAL VT. WITH WEAK INSTABILITY DEVELOPING WITH
COLD POOL ALOFT...FULLY EXPECT ACTIVITY TO BE MORE WIDESPREAD
DURING BOTH THURSDAY AND FRIDAY AFTN...WITH ACTIVITY A BIT MORE
CONCENTRATED NEAR THE UPR LOW DURING THE OVERNIGHT PERIOD THURSDAY
NIGHT. COULD BE COLD ENOUGH (WBZ HEIGHTS 6-7 KFT) TO RESULT IN
SOME PEA-SIZED HAIL WITH STRONGER CORES BOTH THURSDAY AND FRIDAY
AFTERNOONS. HAVE LEFT OUT SPECIFIC MENTION OF THAT FOR NOW GIVEN
WEAK INSTABILITY (<500 J/KG)...BUT HAVE INCLUDED A SLIGHT CHANCE
OF TSTMS FROM THE GREEN MTNS WWD ON THURSDAY AFTN...AND AREAWIDE
FRIDAY AFTN.
COVERAGE OF SHOWERS SHOULD DIMINISH NW-SE FRIDAY NIGHT AS UPR LOW
BEGINS TO DEPART SOUTHEAST OF NEW ENGLAND. WILL SHOW DRYING
CONDITIONS AND PARTIAL CLEARING IN THE FORECAST GRIDS FOR FRIDAY
NIGHT.
HYDROLOGICALLY...NEED TO BEWARE OF ANY POTENTIAL SURPRISE UNDER
THE UPPER LOW...BUT AT THIS POINT IT APPEARS HIGHEST RAINFALL AMTS
OF 1.0-1.5" WILL BE FOCUSED ACROSS NRN NY...AND NOT ENOUGH TO
RESULT IN FLOODING. GIVEN SATURATED CONDITIONS...THE BASIN TO
WATCH MOST CLOSELY WILL BE THE AUSABLE...WHICH ROSE TO NEAR 9 FEET
(ASFN6) EARLY SUNDAY WITH THE LAST HVY RAIN PRODUCING SYSTEM. THE
RAINFALL WILL ALSO BE STRETCHED OUT ACROSS A 36-48 HOUR PERIOD. IN
COMBINATION WITH ACTIVELY GROWING VEGETATION THIS TIME OF
YEAR...RUNOFF SHOULDN`T BE A SIGNIFICANT CONCERN GIVEN CURRENT QPF
EXPECTATIONS.
REMAINED CLOSE TO MOS CONSENSUS FOR DAYTIME HIGHS...GENERALLY UPR 60S
TO LOWER 70S ON THURSDAY...AND MID-UPR 60S FRIDAY WITH COLD POOL
ALOFT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM EDT WEDNESDAY...AS SFC HIGH PRESSURE BUILDS OVER THE
CENTRAL GREAT LAKES REGION ON SATURDAY...AN UPPER LVL RIPPLE OF
ENERGY ALONG WITH SOME INSTABILITY WILL ALLOW FOR SCT RAIN SHOWERS
WITH PSBL TS OVER THE NORTH COUNTRY. THE SFC RIDGE WILL SLIDE SEWD
ON SUNDAY...WITH RIDING ALOFT GRADUALLY MOVING EWD...PUTTING THE
NORTH COUNTRY ON THE PERIPHERY OF HIGH PRESSURE. THIS WILL CAUSE A
DRYING TREND...BUT UPPER LVL DISTURBANCE TRIES TO AFFECT THE
AREA...SO CANNOT COMPLETELY RULE OUT ISOLD-SCT SHOWERS OVER VT ON
SUNDAY.
AS THE SFC RIDGE SLIDES INTO THE ATLANTIC OFF THE SERN USA...WE WILL
SEE A BRIEF DRY PERIOD SUNDAY NGT THROUGH MONDAY. SUNDAY
NGT...WEAKENING RIDGING ALOFT AND LOW PRESSURE SYSTEM AT THE SFC
WILL BRING ANOTHER CHANCE FOR SHOWERS...ESP ON TUESDAY.
THIS ACTIVE PATTERN WILL SEE TEMPS ABOVE NORMAL WITH GENERAL
WARMING TREND. SATURDAY...BEING THE COOLEST DAY WILL HAVE MAX TEMPS
IN THE 50S ACROSS THE MTNS AND 60S-AROUND 70 IN THE VALLEYS. WARMEST
DAY LOOKS TO BE MONDAY WITH MTNS IN THE 60S AND VALLEYS IN THE
L70S-L80S. TUESDAY AND WEDNESDAY CONTINUE TO BE MILD. AT NIGHT...MIN
TEMPS WILL RANGE FROM 40S-L50S IN THE MTNS AND 50S IN THE VALLEYS.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...EXPECTING VFR CONDITIONS FOR THE MAJORITY OF
THE PERIOD...WITH SCATTERED BRIEF PERIODS OF MVFR/IFR POSSIBLE.
SCATTERED VFR CLOUDS WITH CEILINGS 10000 FEET OR ABOVE WILL
GRADUALLY INCREASE IN COVERAGE AND LOWER THROUGH THE NIGHT AND
EARLY THURSDAY MORNING. SOME ISOLATED SHOWERS THIS EVENING AND
TONIGHT ARE POSSIBLE AT MSS/SLK/RUT BUT COVERAGE IS SO LIMITED
THAT WILL ONLY SHOW WITH VCSH FOR NOW. ADDITIONAL MORE WIDESPREAD
SHOWER AND POSSIBLE THUNDERSTORM DEVELOPMENT IS EXPECTED AFTER 14Z
THURSDAY AT ALL TAF SITES. CEILINGS/VISIBILITIES WILL BE PRIMARILY
VFR...HOWEVER SOME PERIODS OF REDUCTIONS TO MVFR OR EVEN IFR ARE
POSSIBLE IN ANY HEAVIER OR MORE ORGANIZED SHOWER ACTIVITY. WINDS
WILL BE LIGHT AND LOCALLY VARIABLE TONIGHT...BECOMING GENERALLY
SOUTH/SOUTHEAST AT 5-10 KNOTS ON THURSDAY...EXCEPT MSS WHERE
NORTHEAST WINDS ARE EXPECTED THROUGH THE PERIOD.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
00Z FRI THRU 00Z SAT...PRIMARILY VFR ALTHOUGH REDUCTIONS TO
MVFR/IFR AT TIMES IN SCATTERED SHOWERS/THUNDERSTORMS.
00Z SAT THRU 00Z MON...MAINLY VFR WITH SCATTERED MVFR SHOWERS
SATURDAY AFTERNOON...AND ISOLATED SHOWERS SUNDAY AFTERNOON.
00Z MON ONWARD...GENERALLY DRY WITH VFR CONDITIONS UNDER SFC HIGH
PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...JMG/BANACOS
SHORT TERM...BANACOS
LONG TERM...KGM
AVIATION...KGM/MUCCILLI
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1031 PM EDT WED MAY 21 2014
.SYNOPSIS...
WARM AND MAINLY DRY CONDITIONS WILL CONTINUE AS HIGH PRESSURE REMAINS
TO THE SOUTH. AFTER A VERY WARM DAY THURSDAY...A COLD FRONT WILL
DROP SOUTH ON FRIDAY...AND WILL STALL JUST SOUTH OF THE AREA THROUGH
THE WEEKEND. TEMPERATURES BEHIND THIS FRONT WILL BE COOLER...BUT
SEASONABLE AND DRY CONDITIONS ARE EXPECTED INTO THE MEMORIAL DAY
HOLIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM WEDNESDAY...I HAVE TRIMMED BACK POPS A LITTLE MORE
BASED MAINLY ON DATA COLLECTED FROM THE 00Z GSO WEATHER BALLOON
SHOWING A 3 DEGREE CELSIUS INVERSION BETWEEN 11000-12000 FEET. THIS
WOULD TEND TO CAP OFF ANY CUMULUS GROWING FROM BELOW. EACH RUN OF
THE HRRR MODEL CONTINUES TO SHOW SCATTERED SHOWERS DEVELOPING AROUND
MIDNIGHT ACROSS EASTERN NC...BUT THIS SEEMS THERMODYNAMICALLY
UNLIKELY GIVEN THE WEATHER BALLOON DATA. NO OTHER SIGNIFICANT
CHANGES. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...
SURFACE HIGH PRESSURE OFF THE FL/GA COAST IS PRODUCING A STEADY SW
BREEZE...STRONGEST NEAR THE COAST WHERE SEABREEZE INFLUENCE HAS
INCREASED WIND SPEEDS TO NEAR 20 MPH. ALOFT THE FLOW IS STRONGLY
VEERED TO THE NW AT AND ABOVE 850 MB DUE TO THE MID AND UPPER LEVEL
RIDGE STILL CENTERED BACK OVER THE LOWER MISSISSIPPI VALLEY.
THE CONCERN FOR TONIGHT IS HOW MUCH INFLUENCE THE EASTERN CAROLINAS
GET FROM A DEVELOPING MCS ACROSS THE OHIO VALLEY. MODELS ALL SHOW
THIS ACTIVITY MAKING INTO THE NC/VA MOUNTAINS LATER THIS EVENING...
BUT THE MOUNTAINS MAY TAKE THEIR TOLL ON THE STORMS AS HIGH-RES
MODEL DEPICTIONS SHOW ONLY LIMITED CONVECTION SURVIVING THROUGH THE
PIEDMONT AND COASTAL PLAIN. LAPSE RATES ALOFT ARE STEEP...TONIGHT`S
850 MB TEMP OF +17C VERSUS A 500 MB TEMP OF -11C TELLS THAT PART OF
THE STORY. COUPLED LOW AND MID LEVEL LIFT AHEAD OF AN UPPER LEVEL
DISTURBANCE EMBEDDED IN THE NW FLOW ALOFT WILL SERVE AS THE
CONVECTIVE TRIGGER...BUT THE LIMITING FACTOR WILL BE HOW MUCH
MOISTURE CAN POOL AT THE BASE OF THE STEEP LAPSE RATES NEAR 850 MB?
MODELS DEFINITELY SHOW MORE 850 MB MOISTURE ACROSS NC THAN SC...AND
GIVEN THIS LIMITED "THUNDERSTORM FUEL" OVER SC I HAVE REMOVED POPS
THERE. IF ACTIVITY CAN SURVIVE THIS FAR SOUTH AND EAST THE WINDOW OF
THUNDERSTORM POTENTIAL WILL BE FROM MIDNIGHT UNTIL 4 AM...GENERALLY
ALONG AND NORTH OF A LINE FROM BENNETTSVILLE THROUGH DILLON...
WHITEVILLE...OAK ISLAND AND SOUTHPORT.
THE PRESENCE OF PERIODS OF CIRRUS CLOUD COVER PLUS THE SOUTHWEST
BREEZE MUCH OF THE NIGHT SHOULD HELP KEEP LOWS IN THE UPPER 60S
INLAND TO NEAR 70 ON THE COAST. THIS IS A LITTLE ABOVE THE WARMEST
MOS GUIDANCE AND NEAR THE BIAS-CORRECTED GFS NUMBERS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 240 PM WEDNESDAY...ALTHOUGH THE 500 MB RIDGE WILL REMAIN
CENTERED OVER THE GULF COAST STATES THURSDAY...IT WILL SHIFT EAST
ENOUGH TO RESULT IN HEIGHT RISES OVER THE CAROLINAS...AS WELL AS
THE EXPANSION OF UNSEASONABLY HOT AIR INTO THE AREA. MODELS STILL
INDICATE 850 MB TEMPS TO 18C AS FAR NORTH AS THE NC-SC STATE LINE.
12Z GUIDANCE IS CONSISTENT AND REMAINS IN LINE WITH GOING FORECAST
OF LOW TO MID 90S EVERYWHERE AWAY FROM THE IMMEDIATE COAST...WHERE
HIGHS ARE EXPECTED TO REACH THE MID 80S. CAN`T RULE OUT A LATE
AFTERNOON OR EVENING THUNDERSTORM GIVEN THE STRONG HEATING AND
WEAK CONVERGENCE ALONG A SURFACE TROUGH INLAND.
A 500 MB SHORTWAVE WILL HELP USHER THE TROUGH/FRONT SOUTH THROUGH
THE CWA THURSDAY NIGHT...AND SURFACE HIGH PRESSURE WILL BUILD IN
FROM THE NORTHWEST. THE SHORTWAVE WILL FLATTEN OUT THE MID-LEVEL
RIDGING OVER THE AREA...THEREFORE MAX TEMPS FRIDAY WILL FALL BACK
A FEW DEGREES. ISOLATED CONVECTION WILL REMAIN A POSSIBILITY GIVEN
ANOTHER DAY OF STRONG HEATING AND NORTHWESTERLY FLOW ALOFT.
TIME-HEIGHT CROSS SECTIONS CONTINUE TO INDICATE RAPID DRYING OF
THE COLUMN UNDERWAY BY 06Z SATURDAY. THEREFORE METEOR SHOWER
ENTHUSIASTS HAVE REASON TO BE OPTIMISTIC AS LOW/MID CLOUDS SHOULD
NOT IMPEDE VISIBILITY LATE FRIDAY NIGHT. CAN`T RULE OUT A THIN
LAYER OF CIRRUS HOWEVER.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...FAIRLY DEEP UPPER TROUGH FORMS OFF NEW
ENGLAND COAST OVER THE WEEKEND DRIVING A VERY PLEASANT AIRMASS
INTO THE SOUTHEASTERN U.S. TEMPERATURE DEVIATIONS FROM CLIMATOLOGY
WILL BE MORE PRONOUNCED AT NIGHT THAN BY DAY...AND THE LOWERED RH
WILL BE VERY NOTICEABLE. UPPER RIDGE BUILDS OVERHEAD ON MONDAY AND
SOME LIGHT RETURN FLOW MAY GET UNDERWAY. THIS SHOULD TRANSLATE TO
A WARMING TREND AS WELL AS AN INCREASE IN DEWPOINTS/RH. A
FLATTENING OF THE RIDGE ALOFT PAIRED WITH THE FORMATION OF A
PIEDMONT TROUGH CALLS FOR LOW CHANCES OF MAINLY DIURNAL
CONVECTION. TEMPERATURES WILL BE VERY NEAR CLIMATOLOGY NEXT WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...EXPECT VFR TO PREVAIL THROUGH THE VALID TAF PERIOD.
LATEST SATELLITE IMAGERY DEPICTS MID TO HIGH CLOUDS TO THE NORTHWEST
IN CORRELATION WITH THUNDERSTORM ACTIVITY SLOWLY MOVING SOUTHEAST
TOWARDS THE AREA. WHILE COULD NOT COMPLETELY RULE OUT AN ISOLATED
SHOWER OR THUNDERSTORM MUCH LATER TONIGHT INTO THE EARLY OVERNIGHT
HOURS AT KLBT/KILM PER SUGGESTION OF SOME MODEL
GUIDANCE...CONFIDENCE IS LOW AND DO NOT EXPECT ANY RESTRICTIONS TO
OCCUR AS A RESULT. AS FOR WINDS CAN EXPECT SOUTHWEST WINDS BECOMING
AOB 10 KTS THROUGH THE OVERNIGHT HOURS. ON THURSDAY...EXPECT VFR
WITH THE POSSIBILITY OF ISOLATED TO SCATTERED AFTERNOON SHRA/TSRA.
WESTERLY WINDS WILL PREVAIL WITH SUSTAINED WINDS INCREASING TO AOB
12 KTS WITH AFTERNOON GUSTS POSSIBLE.
EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD.
CHANCE OF SHOWERS THURSDAY THROUGH SATURDAY MORNING WITH A COLD
FRONT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM WEDNESDAY...NO SIGNIFICANT CHANGES HAVE BEEN MADE WITH
THIS UPDATE. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...
HIGH PRESSURE EAST OF THE GA/FL COAST IS MAINTAINING A HEALTHY
SOUTHWEST WIND ACROSS THE COASTAL WATERS. ADD IN SOME EXTRA WIND
FROM THE AFTERNOON SEABREEZE AND WE`RE SEEING A SOLID 20 KNOTS
ACROSS MOST OF THE COASTAL WATERS CURRENTLY. WINDS ACROSS THE SC
WATERS SHOULD NOT INCREASE TONIGHT AND WILL ACTUALLY DIMINISH AFTER
MIDNIGHT AS WIND DIRECTIONS TURN MORE WESTERLY IN ASSOCIATION WITH
AN UPPER LEVEL DISTURBANCE PASSING THROUGH TO OUR NORTH. ACROSS THE
NC WATERS WINDS MAY INCREASE ANOTHER 3-5 KNOTS BY MIDNIGHT AHEAD OF
THE UPPER DISTURBANCE...BUT EVEN HERE SHOULD DIMINISH LATE TONIGHT
AS DIRECTIONS TURN WESTERLY.
I HAVE MAINTAINED THE SMALL CRAFT ADVISORY FOR THE NC WATERS WHERE
SEAS SHOULD BUILD TO 5-6 FEET OUT BEYOND 10 MILES FROM SHORE...
ESPECIALLY JUST EAST OF BALD HEAD ISLAND WHERE THE EFFECTIVE FETCH
LENGTH IS QUITE LONG ON A SW WIND.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 240 PM WEDNESDAY...LOW PRESSURE MOVING EAST OFF THE
DELMARVA PENINSULA WILL COMBINE WITH HIGH PRESSURE OVER THE GULF
COAST TO PRODUCE WESTERLY WINDS ACROSS THE AREA WATERS. THE
GRADIENT WILL WEAKEN THROUGH THE DAY AS THE LOW MOVES TO THE EAST.
A WEAK SURFACE TROUGH/FRONT WILL DROP SOUTH ACROSS THE WATERS
THURSDAY NIGHT RESULTING IN A SHIFT TO NORTHERLY WINDS. THE
GRADIENT WILL TEMPORARILY WASH OUT FRIDAY WITH WINDS BECOMING
VARIABLE. HIGH PRESSURE WILL PUSH ACROSS THE CAROLINAS FRIDAY
NIGHT AND RESULT IN A LATE NIGHT NORTHERLY SURGE TO 15-20 KTS.
WILL HAVE TO MONITOR THE PROGRESSION OF ANY CONVECTION THAT
DEVELOPS INLAND BOTH THURSDAY AND FRIDAY...AS DEEP NORTHWEST FLOW
COULD PUSH THIS ACTIVITY ACROSS THE COASTAL WATERS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 240 PM WEDNESDAY...N TO NE WINDS ON SATURDAY WILL FOLLOW IN
THE WAKE OF FRIDAY COLD FRONT. FLOW WILL REMAIN LIGHT...NO SURGE
OF COOLER AIR OR HIGHER PRESSURES NORMALLY ASSOCIATED WITH COOL
SEASON FROPAS. CENTER OF HIGH PRESSURE DRAWS NEARER BUT REMAINS TO
OUR NORTH ON SUNDAY LEADING TO A VEER TO AN ONSHORE/EASTERLY FLOW.
WIND SPEEDS REMAIN EXCEEDINGLY LIGHT BUT WILL SEE A LOCALIZED
ACCELERATION OF A FEW KNOTS ALONG THE IMMEDIATE COAST DUE TO SEA
BREEZE CIRCULATION. VEERING WINDS/CLOCKWISE CHANGE IN DIRECTION
CONTINUES INTO MONDAY AS THE CENTER OF THE HIGH PROGRESSES
EASTWARD. NOT SEEING ANY APPRECIABLE INCREASE IN WIND SPEED BUT
THE LONGER FETCH SETTING UP MAY ALLOW FOR A VERY MINOR SWELL
COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...CRM
LONG TERM...MBB
AVIATION...SGL
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 GRAND FORKS ND
922 PM CDT WED MAY 21 2014
.UPDATE...
ISSUED AT 922 PM CDT WED MAY 21 2014
CLOUDS ACROSS NORTHWEST MINNESOTA REMAIN IN PLACE AND ARE ERODING
FROM THE WEST MUCH SLOWER THAN FORECASTED. WILL AGAIN DELAY THE
CLEARING TREND. CURRENT RAP/HRRR RUNS SUGGEST CLEARING BY
12Z...BUT DO DELAY THE CLEARING BY SEVERAL HOURS FROM PREVIOUS
RUNS. WHERE/IF CLOUDS REMAIN MIN TEMPS WILL BE AFFECTED...AND DID
RAISE VALUES SLIGHTLY AROUND THE BAUDETTE/WASKISH AREA WHERE
CLOUD SHOULD REMAIN THROUGH MUCH OF THE NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 317 PM CDT WED MAY 21 2014
ISSUE EARLY ON IS CLEARING TREND IN NW MN. OTHERWISE QUIET THRU
THURSDAY NIGHT. 500 MB SHORT WAVE/SFC LOW SLOWLY MOVING EAST AND
NOW NORTH OF LAKE SUPERIOR. WRAPAROUND MOISTURE SLOWLY PULLING
EAST WITH CLEARING PROGRESSING INTO THE RRV AT MID AFTN WITH
CLEARING LIKELY REACHING BAUDETTE-WASKISH LATE EVENING. HIGH
PRESSURE WILL MOVE OVERHEAD WITH CLEAR SKY OVERNIGHT BEHIND THE
CLEARING AND WINDS WILL DIMINISH. EXPECT LOWS 40-45. WINDS WILL
BEGIN TO TURN SOUTHEAST-SOUTHERLY THURSDAY AND TEMPS WILL WARM UP
WITH SOME HIGHS MID 60S TO LOWER 70S. CLEAR INTO THURSDAY EVE BUT
THEN SOME 850-700 MB WARM ADVECTION MOVES INTO CNTRL ND LATE THU
NIGHT AND COULD BE A FEW ELEVATED STORMS WITH THIS SO KEPT 20 POP
FOR DVL REGION.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 317 PM CDT WED MAY 21 2014
FOR FRI-SAT...MODELS DO PAINT A MORE UNSTABLE SITUATION AS
MOISTURE/WARMTH AND INSTABILITY RETURN NORTHWARD AROUND SFC HIGH
DROPPING INTO THE SOUTHERN GREAT LAKES. HOW FAR EAST AND HOW FAST
INSTABILITY AND MOISTURE GETS IS QUESTIONABLE WITH GFS WETTER AND
FASTER WITH TSTM CHANGES VS GEM/ECMWF. ATTM SIDE WITH A TAD SLOWER
SOLN AND KEEP ANY STORM THREAT MORE SO DVL REGION SOUTHWEST THRU
CNTRL ND FRI DAYTIME-FRI EVE. WILL SPREAD CHC OF STORMS OVER THE
REST OF THE AREA SATURDAY...WITH MAIN THREAT FOR THUNDERSTORMS
MORE SO LATE SATURDAY AFTN-NIGHT. AXIS OF INSTABILITY IS MORE FROM
SOUTHWEST MANITOBA INTO WRN/CNTRL ND/ERN ND SAT AFTN-EVE WHERE SOME
STRONG OR ISOLD SEVERE STORM NOT OUT OF THE QUESTION.
SAT NIGHT TO WEDNESDAY...500MB FLOW FOR THE FIRST HALF OF NEXT WEEK
WILL BE PREDOMINANTLY SOUTHWEST AS THE ROCKIES AND CENTRAL PLAINS
SEES A WEAK CUTOFF LOW SPIN ACROSS THE CENTRAL US BENEATH THE RIDGE
WELL LIFTING INTO CANADA. AS A RESULT SHOWER AND TSTORMS POSSIBLE
WITH ANY PERTURBATIONS IN THE FLOW AS ADEQUATE MOISTURE EXISTS WITH
PWATS BETWEEN 1.0IN TO 1.5IN. MODELS PEGGING THE BEST CHANCE AND
STRONGEST WAVE TO MOVE ACROSS THE CWFA ON SAT NIGHT SUN AM WITH JUST
SLIGHT CHC SUN PM AND THEREAFTER. TEMPS WILL BE ABOVE LATE MAY
NORMALS WITH MAX TEMPS PUSHING 80 SUN AND UPPER 70S FOR THE REST OF
THE WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 922 PM CDT WED MAY 21 2014
BUILDING HIGH PRESSURE WILL LEAD TO LIGHT WINDS AND CLEARING
SKIES. MVFR CLOUDS REMAIN ACROSS NORTHWEST MINNESOTA...AFFECTING
KTVF AND KBJI. WILL FOLLOW THE LATEST RAP GUIDANCE FOR TIMING OF
CLEARING SKIES (AROUND 04Z-05Z FOR KTVF AND AROUND 09Z-11Z FOR KBJI).
THE OTHER TAF SITES WILL BE CLEAR THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...JK/RIDDLE
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
623 PM CDT WED MAY 21 2014
.UPDATE...
ISSUED AT 623 PM CDT WED MAY 21 2014
CLOUDS ACROSS NORTHWEST MINNESOTA ARE LIKELY MORE STRATUS THAN
CELLULAR AS THEY ARE NOT DISSIPATING YET. WILL DELAY THE CLEARING
ACROSS THIS AREA BY 3-6 HOURS. AS THE SFC RIDGE WORKS INTO THE
REGION THESE CLOUDS WILL DISSIPATE OR MOVE OFF TO THE EAST. OTHER
FORECASTED PARAMETERS SHOULD NOT BE MUCH AFFECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 317 PM CDT WED MAY 21 2014
ISSUE EARLY ON IS CLEARING TREND IN NW MN. OTHERWISE QUIET THRU
THURSDAY NIGHT. 500 MB SHORT WAVE/SFC LOW SLOWLY MOVING EAST AND
NOW NORTH OF LAKE SUPERIOR. WRAPAROUND MOISTURE SLOWLY PULLING
EAST WITH CLEARING PROGRESSING INTO THE RRV AT MID AFTN WITH
CLEARING LIKELY REACHING BAUDETTE-WASKISH LATE EVENING. HIGH
PRESSURE WILL MOVE OVERHEAD WITH CLEAR SKY OVERNIGHT BEHIND THE
CLEARING AND WINDS WILL DIMINISH. EXPECT LOWS 40-45. WINDS WILL
BEGIN TO TURN SOUTHEAST-SOUTHERLY THURSDAY AND TEMPS WILL WARM UP
WITH SOME HIGHS MID 60S TO LOWER 70S. CLEAR INTO THURSDAY EVE BUT
THEN SOME 850-700 MB WARM ADVECTION MOVES INTO CNTRL ND LATE THU
NIGHT AND COULD BE A FEW ELEVATED STORMS WITH THIS SO KEPT 20 POP
FOR DVL REGION.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 317 PM CDT WED MAY 21 2014
FOR FRI-SAT...MODELS DO PAINT A MORE UNSTABLE SITUATION AS
MOISTURE/WARMTH AND INSTABILITY RETURN NORTHWARD AROUND SFC HIGH
DROPPING INTO THE SOUTHERN GREAT LAKES. HOW FAR EAST AND HOW FAST
INSTABILITY AND MOISTURE GETS IS QUESTIONABLE WITH GFS WETTER AND
FASTER WITH TSTM CHANGES VS GEM/ECMWF. ATTM SIDE WITH A TAD SLOWER
SOLN AND KEEP ANY STORM THREAT MORE SO DVL REGION SOUTHWEST THRU
CNTRL ND FRI DAYTIME-FRI EVE. WILL SPREAD CHC OF STORMS OVER THE
REST OF THE AREA SATURDAY...WITH MAIN THREAT FOR THUNDERSTORMS
MORE SO LATE SATURDAY AFTN-NIGHT. AXIS OF INSTABILITY IS MORE FROM
SOUTHWEST MANITOBA INTO WRN/CNTRL ND/ERN ND SAT AFTN-EVE WHERE SOME
STRONG OR ISOLD SEVERE STORM NOT OUT OF THE QUESTION.
SAT NIGHT TO WEDNESDAY...500MB FLOW FOR THE FIRST HALF OF NEXT WEEK
WILL BE PREDOMINANTLY SOUTHWEST AS THE ROCKIES AND CENTRAL PLAINS
SEES A WEAK CUTOFF LOW SPIN ACROSS THE CENTRAL US BENEATH THE RIDGE
WELL LIFTING INTO CANADA. AS A RESULT SHOWER AND TSTORMS POSSIBLE
WITH ANY PERTURBATIONS IN THE FLOW AS ADEQUATE MOISTURE EXISTS WITH
PWATS BETWEEN 1.0IN TO 1.5IN. MODELS PEGGING THE BEST CHANCE AND
STRONGEST WAVE TO MOVE ACROSS THE CWFA ON SAT NIGHT SUN AM WITH JUST
SLIGHT CHC SUN PM AND THEREAFTER. TEMPS WILL BE ABOVE LATE MAY
NORMALS WITH MAX TEMPS PUSHING 80 SUN AND UPPER 70S FOR THE REST OF
THE WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 623 PM CDT WED MAY 21 2014
BUILDING HIGH PRESSURE WILL LEAD TO LIGHT WINDS AND CLEARING
SKIES. MVFR CLOUDS REMAIN ACROSS NORTHWEST MINNESOTA...AFFECTING
KTVF AND KBJI. WILL FOLLOW THE LATEST RAP GUIDANCE FOR TIMING OF
CLEARING SKIES (AROUND 02Z FOR KTVF AND AROUND 04Z FOR KBJI). THE
OTHER TAF SITES WILL BE CLEAR THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...JK/RIDDLE
AVIATION...TG
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
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
918 PM MDT WED MAY 21 2014
.UPDATE...
ISSUED AT 914 PM MDT WED MAY 21 2014
03Z SURFACE ANALYSIS SHOWED WEAK HIGH PRESSURE OVER THE DAKOTAS
WITH SEVERAL BOUNDARIES FROM WY INTO CO/WESTERN NE. WATER VAPOUR
LOOP SHOWED UPPER LOW OVER NV SPINNING SEVERAL WEAK SHORTWAVES
FROM UT/CO INTO WY/WESTERN NE/SOUTHWEST SD. 00Z GUIDANCE SHOWS
WEAK 850-700MB THETA-E ADVECTION ON WEAK 25KT SOUTHERLY BOUNDARY
LAYER FLOW WILL CREATE SOME SHRA/TSRA OVERNIGHT...ESPECIALLY OVER
FAR SOUTHWEST THROUGH CENTRAL SD. HAVE ADJUSTED POPS TO DELAY
CHANCE POPS AND ADJUST FOR LATEST TRENDS.
&&
.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 226 PM MDT WED MAY 21 2014
CURRENT SURFACE MAP PLACES HIGH PRESSURE ACROSS THE EASTERN
DAKOTAS. PERSISTENT LOW CLOUDS ACROSS NORTHEAST WYOMING HAS
LIMITED SURFACE BASED INSTABILITY. THUNDERSTORMS DEVELOPING OVER
EAST CENTRAL WYOMING INTO COLORADO. LATEST RADAR TRENDS AND
CURRENT RUN OF HRRR BRINGS THUNDERSTORMS INTO NORTHEAST
WYOMING/FAR SOUTHWEST SOUTH DAKOTA THIS EVENING. THUNDERSTORMS
SHOULD PERSIST OVERNIGHT ACROSS WESTERN SOUTH DAKOTA WITH WEAK
850-700MB THETA-E ADVECTION AND STEEP MID LEVEL LAPSE RATES.
HIGH MOVES EAST FOR THURSDAY...WITH INSTABILITY AXIS CREEPING
FURTHER NORTHWARD. WITH LACK OF LARGE SCALE FORCING UNDER UPPER
RIDGE AXIS...THUNDERSTORM ACTIVITY MAY BE LIMITED TO THE HIGHER
TERRAIN OF NORTHEAST WYOMING INTO THE BLACK HILLS.
&&
.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 226 PM MDT WED MAY 21 2014
SOUTHWEST FLOW ALOFT REMAINS ACROSS THE REGION LATE THIS WEEK INTO
THE WEEKEND...WITH SEVERAL SHORTWAVE DISTURBANCES EJECTING OUT OF A
PERSISTENT TROF/CUT OFF LOW OVER THE WESTERN UNITED STATES. AN
ACTIVE AND UNSETTLED WEATHER PATTERN WILL CONTINUE...WITH DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE PERIOD.
MEDIUM RANGE MODELS CONTINUE TO SHOW GOOD AGREEMENT ON THE TRACK AND
TIMING OF UPPER LOW AS IT MOVES FROM THE SOUTHWEST CONUS INTO THE
CENTRAL PLAINS LATER IN THE HOLIDAY WEEKEND. CHANCES FOR PCPN SHOULD
DECREASE BY MONDAY AS THE LOW TRACKS SOUTH AND EAST OF THE AREA.
TEMPERATURES WILL GENERALLY BE A BIT ABOVE AVERAGE THROUGH THE
PERIOD...WITH HIGHS MOSTLY IN THE 70S ON THE PLAINS...60S AND LOWER
70S ACROSS THE BLACK HILLS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 914 PM MDT WED MAY 21 2014
A FEW SHRA/TSRA WILL MOVE ACROSS THE AREA THROUGH THURSDAY. LOCAL
MVFR CIGS/VSBYS WITH GUSTY WINDS IN THE VICINITY OF THE HEAVIEST
SHRA. OUTSIDE OF PRECIPITATION...PATCHY MVFR CIGS MAY OCCUR.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...47
LONG TERM...13
AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
525 PM MDT WED MAY 21 2014
.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 226 PM MDT WED MAY 21 2014
CURRENT SURFACE MAP PLACES HIGH PRESSURE ACROSS THE EASTERN
DAKOTAS. PERSISTENT LOW CLOUDS ACROSS NORTHEAST WYOMING HAS
LIMITED SURFACE BASED INSTABILITY. THUNDERSTORMS DEVELOPING OVER
EAST CENTRAL WYOMING INTO COLORADO. LATEST RADAR TRENDS AND
CURRENT RUN OF HRRR BRINGS THUNDERSTORMS INTO NORTHEAST
WYOMING/FAR SOUTHWEST SOUTH DAKOTA THIS EVENING. THUNDERSTORMS
SHOULD PERSIST OVERNIGHT ACROSS WESTERN SOUTH DAKOTA WITH WEAK
850-700MB THETA-E ADVECTION AND STEEP MID LEVEL LAPSE RATES.
HIGH MOVES EAST FOR THURSDAY...WITH INSTABILITY AXIS CREEPING
FURTHER NORTHWARD. WITH LACK OF LARGE SCALE FORCING UNDER UPPER
RIDGE AXIS...THUNDERSTORM ACTIVITY MAY BE LIMITED TO THE HIGHER
TERRAIN OF NORTHEAST WYOMING INTO THE BLACK HILLS.
&&
.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 226 PM MDT WED MAY 21 2014
SOUTHWEST FLOW ALOFT REMAINS ACROSS THE REGION LATE THIS WEEK INTO
THE WEEKEND...WITH SEVERAL SHORTWAVE DISTURBANCES EJECTING OUT OF A
PERSISTENT TROF/CUT OFF LOW OVER THE WESTERN UNITED STATES. AN
ACTIVE AND UNSETTLED WEATHER PATTERN WILL CONTINUE...WITH DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH MUCH OF THE PERIOD.
MEDIUM RANGE MODELS CONTINUE TO SHOW GOOD AGREEMENT ON THE TRACK AND
TIMING OF UPPER LOW AS IT MOVES FROM THE SOUTHWEST CONUS INTO THE
CENTRAL PLAINS LATER IN THE HOLIDAY WEEKEND. CHANCES FOR PCPN SHOULD
DECREASE BY MONDAY AS THE LOW TRACKS SOUTH AND EAST OF THE AREA.
TEMPERATURES WILL GENERALLY BE A BIT ABOVE AVERAGE THROUGH THE
PERIOD...WITH HIGHS MOSTLY IN THE 70S ON THE PLAINS...60S AND LOWER
70S ACROSS THE BLACK HILLS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 523 PM MDT WED MAY 21 2014
A FEW SHRA/TSRA WILL MOVE ACROSS THE AREA THROUGH THURSDAY. LOCAL
MVFR CIGS/VSBYS WITH GUSTY WINDS IN THE VICINITY OF THE HEAVIEST
SHRA. OTHERWISE...LINGERING AREAS MVFR CIGS WILL PERSIST OVER
NORTHEAST WY/SOUTHWEST SD TONIGHT...WITH IMPROVEMENT THURSDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...47
LONG TERM...13
AVIATION...HELGESON
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 BLACKSBURG VA
749 PM EDT WED MAY 21 2014
.SYNOPSIS...
A COLD FRONT IN THE GREAT LAKES THIS EVENING...WILL SLIDE THROUGH
THE AREA THURSDAY NIGHT...LEADING IN A RETURN TO DRIER AND
SLIGHTLY COOLER WEATHER AS HIGH PRESSURE BUILDS IN FOR THE
WEEKEND. THE HIGH MOVES OFFSHORE BY MONDAY BRINGING A RETURN TO
MORE SUMMER-LIKE WEATHER WITH A DAILY CHANCE FOR AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 720 PM EDT WEDNESDAY...
HAVE ADJUSTED POPS DOWN BASED ON LATEST RADAR/MESOANALYSIS TRENDS.
WILL MAINTAIN INCREASING POPS OVER THE WRN CWA AS CONVECTION NOW
OVER CENTRAL WV SLIDES SOUTHWARD. CORFIDI VECTORS FAVOR SLOWING
AND TURNING MORE TOWARD THE SOUTH INTO FAR SW VA/ERN KY WITH
CLUSTERS OF STORMS THAT ARE NOW LINED UP FROM INDIANA EAST TO CRW.
EVEN THE LATEST HRRR APPEARS TO BE FAVORING HIGHER THETA-E AND
CONVECTION OVER OUR FAR SW CWA BY MIDNIGHT. LIMITED
SHOWERS/THUNDER EXPECTED EAST OF THE ALLEGHANY FRONT NORTH OF
ROA-LYH...WITH NO CHANCE ATTM FOR EAST OF THE BLUE RIDGE SOUTH OF
ROANOKE. MINOR MODIFICATIONS MADE TO THE SKY/TEMPS AND WIND.
PREVIOUS VALID DISCUSSION...
LOW LEVEL JET INCREASES TO AROUND 40 KNOTS OVERNIGHT WHICH WILL KEEP
THE RIDGES BREEZY...WELL MIXED AND MILD. WITH THE FORECAST AREA
STILL IN THE WARM SECTOR...EXPECT MINIMAL DROP IN TEMPERATURES
OVERNIGHT. STAYING CLOSER TO WARMER BIAS CORRECTED MAV GUIDANCE
FOR LOWS.
MODELS BRING THE FRONT THROUGH THE FORECAST AREA LATE THURSDAY.
WINDS WILL BECOME NORTHWEST THROUGH A DEEP LAYER AS MORE STABLE AIR
BEGINS TO ADVECT INTO THE REGION.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 330 PM EDT WEDNESDAY...
SHOWER AND THUNDERSTORMS SHOULD WANE ALONG THE PASSING COLD FRONT
DURING THURSDAY NIGHT. POPS WERE REDUCED TO LEAVE THE WHOLE CWA
DRY AFTER MIDNIGHT. BY FRIDAY...A MODEST UPPER LEVEL TROUGH WILL
CROSS OVER PENNSYLVANIA...AND HIGH PRESSURE WILL BEGIN TO SLIDE
TOWARD THE SOUTHEAST FROM WISCONSIN. THIS OVERALL PATTERN SHOULD
SET UP A DECENT NORTHWEST FLOW OVER THE MID ATLANTIC...WHICH WILL
PUSH THE COLD FRONT SOUTHWARD TO THE CAROLINAS PERHAPS A LITTLE
FASTER THAN THE 12Z MODELS ARE INDICATING. IT WILL ALSO USHER A
COOLER AND DRIER AIR MASS TOWARD THE CWA BY FRIDAY NIGHT.
SATURDAY MORNING COULD BRING ANOTHER TASTE OF UNSEASONABLY COOL
TEMPERATURES...AS LOWS MIGHT TEST THE MID 40S IN THE DEEPEST
MOUNTAIN VALLEYS SUCH AS LEWISBURG AND BURKES GARDEN.
HOWEVER...THE MORNING CHILL WILL GIVE WAY TO PLENTIFUL
SUNSHINE...DIMINISHING NORTHWEST WINDS...AND HIGH TEMPERATURES
GENERALLY IN THE 70S COURTESY OF HIGH PRESSURE APPROACHING FROM
THE OHIO RIVER VALLEY. IT APPEARS THIS MEMORIAL DAY WEEKEND WILL
BE DRY FOR WHATEVER OUTDOOR ACTIVITIES YOU MAY HAVE PLANNED TO
WELCOME THE UNOFFICIAL START OF SUMMER 2014.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 1240 PM EDT TUESDAY...
BY SATURDAY NIGHT...THE MODELS AGREE ON A BROAD 1023 MB SURFACE HIGH
PRESSURE MOVING DIRECTLY OVERHEAD. TEMPERATURES COULD DROP INTO THE
UPPER 40S IN THE MOUNTAIN VALLEYS BY SUNDAY MORNING DUE TO GOOD
RADIATIONAL COOLING. HOWEVER...THE AIR MASS SHOULD MODIFY AS THE
HIGH SLIPS SOUTHWARD TOWARD THE CAROLINAS AND EVENTUALLY OFF THE
COAST. THE RETURN SOUTHERLY FLOW FROM THE GULF OF MEXICO WILL
ENSUE DURING MEMORIAL DAY TO PROVIDE SUMMER-LIKE WEATHER THROUGH
THE REST OF THIS FORECAST PERIOD.
MEANWHILE...AN UPPER LEVEL TROUGH WITH ITS ASSOCIATED COLD FRONT
SHOULD SLOWLY MOVE EASTWARD FROM THE CENTRAL PLAINS DURING THE WORK
WEEK. COMBINED WITH HIGH TEMPERATURES EASILY REACHING THE 80S FOR
MOST LOCATIONS BY TUESDAY AND WEDNESDAY...THE CHANCE FOR AFTERNOON
TO EVENING SHOWERS AND THUNDERSTORMS WILL STEADILY INCREASE. ONLY
ISOLATED ACTIVITY MAY OCCUR ON MEMORIAL DAY DUE TO LIMITED CAPE AND
BOUNDARY LAYER MOISTURE...BUT CONVECTION SHOULD BECOME MORE
PRONOUNCED DURING TUESDAY AND WEDNESDAY. THE HIGHEST POP CHANCES
WERE PLACED WEST OF THE BLUE RIDGE THROUGHOUT THIS PERIOD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 740 PM EDT WEDNESDAY...
FORECAST HINGES ON CONVECTION UPSTREAM OVER THE OHIO VALLEY INTO
WV. NOT SEEING A BIG THREAT OF SHOWERS OR STORMS EXCEPT PERHAPS
LWB/BLF. EVEN THAT WILL BE SMALL AS MAIN ENERGY AND CONVERGENCE
WILL LIE SOUTH AND WEST OF THE MTNS INTO FAR SW VA INTO KY
OVERNIGHT.
THE OTHER ISSUE OVERNIGHT WILL BE FOG POTENTIAL GIVEN INCREASING
HUMID AIR. WINDS STAY UP A BIT SO NOT SEEING A BIG THREAT. GFS
SHOWING A CHANCE OF LOWER CIGS AT BLF/LWB AS WELL AS BCB POST
CONVECTION OVERNIGHT INTO THU MORNING. WILL LEAN TOWARD MVFR CIGS
AT BLF/LWB BUT NOT BCB. ANY FOG EXPECTED TO BE MVFR...ALTHOUGH
CANNOT RULE OUT THAT LWB DROPS TO IFR AFTER 08Z.
FOR THURSDAY...APPEARS SHOWER AND STORM THREAT WILL LIE SOUTHWEST
OF THE CWA AND PERHAPS GRAZING BLF...THEN SOUTH OF DANVILLE IN THE
AFTERNOON. WITH LIMITED THREAT WILL LEAVE ANY MENTION OUT OF TAFS
FOR NOW. SHOULD BE SCT-BKN CU WITH SOME BKN MID/HIGH CLOUDS...SO
VFR EXPECTED WITH A GUSTY WEST TO NORTHWEST WIND.
EXTENDED AVIATION DISCUSSION...
VFR CONDITIONS ARE EXPECTED THURSDAY NIGHT THROUGH SUNDAY NIGHT...WITH
SOME INCREASING POTENTIAL FOR EARLY MORNING MVFR FOG AT LWB/LYH
AND BCB. MONDAY THERE ISOLATED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS ARE POSSIBLE AS HIGH PRESSURE MOVES OFFSHORE AND
DEEPER MOISTURE RETURNS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/WP
SHORT TERM...PW
LONG TERM...PW
AVIATION...AMS/JH/WP
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 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 CHEYENNE WY
552 PM MDT WED MAY 21 2014
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY NIGHT)
ISSUED AT 319 PM MDT WED MAY 21 2014
VISIBLE AND RADAR IMAGERY IS SHOWING TSTMS DEVELOPING IN THE
NORTHERN LARAMIE RANGE. THESE STORMS WILL BE MOVING INTO AN
UNSTABLE ENVIRONMENT OVER THE PLAINS WITH DEWPOINTS OF 45-55F AND
SBCAPES IN THE 1500-2000 J/KG RANGE. WHILE FLOW ALOFT IS WEAKER
THAN YESTERDAY...DEEP LAYER SHEAR OF 35-40 KTS WILL STILL BE
SUFFICIENT FOR SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL. ADDED
THE POTENTIAL FOR LARGE HAIL OVER CONVERSE AND NIOBRARA COUNTIES AS
CONVECTIVE PARAMETERS ARE JUST AS FAVORABLE UP THERE AS FURTHER
SOUTH. STORM INITIATION HAS BEEN QUITE LIMITED SO FAR OVER THE
SOUTHERN LARAMIE RANGE...PERHAPS BECAUSE SFC WINDS ARE MORE
SOUTHERLY OVER LARAMIE COUNTY. THINKING THAT THE STRONGEST STORMS
WILL BE ACROSS SOUTHEAST WY THIS AFTN WITH CAPE DROPPING OFF TO
500-1000 OVER THE NEBRASKA PANHANDLE. WHILE LARGE HAIL WILL BE THE
PRIMARY THREAT...CANNOT RULE OUT AN ISOLATED WEAK TORNADO. 0-1KM
HELICITY VALUES ARE CURRENTLY LESS THAN 50 OVER MUCH OF THE PLAINS
WITH LCL HEIGHTS AROUND 1 KM. THE HRRR HAS BEEN CONSISTENT OVER THE
PAST FEW RUNS AT SHOWING THE MOST WIDESPREAD STORM CONVERGE TO THE
NORTH OF LARAMIE COUNTY...WHICH SEEMS ON TRACK SO FAR. STORMS WILL
BEGIN TO WIND DOWN BY LATE EVENING.
UPPER LEVEL LOW CONTINUES TO SPIN OVER THE DESERT SOUTHWEST TOMORROW
WITH SOUTH-TO-SOUTHWESTERLY FLOW ALOFT. THE MAIN CHANGE FOR THURS
WILL BE THAT THE WINDS ALOFT WEAKEN SUBSTANTIALLY...THUS THE DEEP
LAYER SHEAR DECREASES. 0-6KM SHEAR VALUES ARE DOWN TO 15-25 KTS
OVER THE PLAINS DURING THE AFTN. THERE IS STILL GOOD INSTABILITY
WITH SBCAPES AROUND OF 1500-1750...SO TSTMS WITH HEAVY RAIN WILL
PROBABLY THE PRIMARY THREAT WITH THE SLOWER STORM MOTIONS...AS
OPPOSED TO LARGE HAIL.
.LONG TERM...(FRIDAY THROUGH TUESDAY NIGHT)
ISSUED AT 319 PM MDT WED MAY 21 2014
THE UPPER LOW WILL SLOWLY MOVE EASTWARD FROM THE DESERT SOUTHWEST
TOWARD THE SOUTHERN PLAINS FRI-SUN. LOOKING AT A GOOD COVERAGE FOR
SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA THROUGH THIS
TIME. HEAVY RAIN IS POSSIBLE WITH SOME OF THIS ACTIVITY...ESPECIALLY
FOR FRIDAY AND SUNDAY. SHORTWAVE RIDGING WILL MOVE OVERHEAD FOR
MONDAY...WITH WARMING TEMPERATURES AND MUCH DRIER CONDITIONS
ANTICIPATED. FLOW ALOFT WILL BACK TO THE SOUTHWEST ON TUESDAY WITH
SHORTWAVE ENERGY MOVING OVERHEAD IN THE AFTERNOON. WILL SEE A RETURN
OF SOME SHOWERS AND AFTERNOON THUNDERSTORMS MAINLY FOR SOUTHEAST
WYOMING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY AFTERNOON)
ISSUED AT 552 PM MDT WED MAY 21 2014
WIDELY SCATTERED SHOWERS AND STORMS WILL CONTINUE THROUGH ABOUT
03Z THIS EVENING BEFORE DISSIPATING. COULD BE A BRIEF PERIOD OF
IFR CIGS/VSBYS IN THE WAKE OF ANY STORMS THAT MOVE THROUGH.
IFR/MVFR STRATUS THEN LOOKS TO DEVELOP DURING THE EARLY MORNING
HOURS FOR THE EASTERN TERMINALS...AND WILL BEGIN TO SLOWLY LIFT
AFTER 14Z. MVFR CIGS ARE EXPECTED TO SPILL INTO THE LARAMIE VALLEY
FROM THE SOUTH OVERNIGHT AS WELL. ANOTHER ROUND OF SHOWERS AND
STORMS IS EXPECTED FOR THURSDAY AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 319 PM MDT WED MAY 21 2014
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. A MOIST AIRMASS WILL
BE IN PLACE ACROSS THE REGION THROUGH THE WEEKEND. THIS WILL CAUSE
SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP EVERY AFTERNOON.
MINIMUM AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 40 PERCENT
AND WINDS WILL BE LIGHT OUTSIDE OF THUNDERSTORMS.
&&
.HYDROLOGY..
ISSUED AT 319 PM MDT WED MAY 21 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 WILL CONTINUE TO
SEE RISES TO AND IN SOME CASES INTO FLOOD STAGE THROUGH THE END OF
THE WEEK. RAIN CHANCES CONTINUE JUST ABOUT EVERY AFTERNOON AND
EVENING THROUGH THE WEEKEND. MODELS SHOW THE POTENTIAL FOR A PERIOD
OF MODERATE RAIN SATURDAY NIGHT AND SUNDAY 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 IF IT MATERIALIZES. WILL
CONTINUE TO MONITOR AND ISSUE ANY WATCHES AS THE EVENT DRAWS CLOSER.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RJM
AVIATION...RJM
FIRE WEATHER...FINCH
HYDROLOGY...FINCH
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
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
334 AM MDT THU MAY 22 2014
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 305 AM MDT THU MAY 22 2014
THE UPPER LEVEL LOW WILL REMAIN OVER THE SWRN US THROUGH TONIGHT AS
A SERIES OF WEAK DISTURBANCES MOVE NNE AHEAD OF THE SYSTEM ACROSS
COLORADO. APPEARS ONE SUCH FEATURE MAY TRACK ACROSS THE AREA THIS
AFTN WHILE ANOTHER MOVES INTO THE AREA LATE TONIGHT. AT THE SFC
WILL PROBABLY SEE A SFC LOW DVLP IN THE SRN FOOTHILLS WITH A
CONVERGENCE ZONE SETTING UP OVER THE PALMER DIVIDE WITH ELY LOW LVL
FLOW FM DENVER NORTH TO THE WY BORDER. SFC BASED CAPES BY AFTN WILL
RANGE FM 1500-2000 J/KG FM THE FOOTHILLS ACROSS THE PLAINS EXCEPT
OVER THE NERN CORNER WHERE CAPES MAY STAY BLO 1000 J/KG. OVERALL
MID LVL FLOW IS FCST TO BE WEAKER TODAY SO SHEAR PROFILE WILL NOT BE
AS STRONG. HOWEVER STILL EXPECT A FEW SVR STORMS THIS AFTN INTO THE
EARLY EVENING HOURS WITH A FEW BRIEF TORNADES POSSIBLE ALONG THE
CONVERGENCE ZN. AT THIS TIME BEST POTENTIAL FOR SVR WEATHER LOOKS
TO BE ALONG AND SOUTH OF A LINE FROM DENVER INTO SRN WASHINGTON
COUNTY UNLESS CONVERGENCE ZN SHIFTS FURTHER NORTH.
PRECIPITABLE WATER VALUES HAVE BEEN SLOWLY INCREASING AND COULD BE
NEAR AN INCH BY LATER THIS AFTN AND WITH SLOWER STORM MOTIONS THERE
WILL BE THE POTENTIAL FOR HEAVIER RAINFALL. AT THIS POINT IT
APPEARS MOST OF THE HEAVIER RAINFALL WILL BE AT LOWER ELEVATIONS
ALTHOUGH THERE COULD BE SOME HEAVY RAIN IN THE FOOTHILLS DUE TO THE
ELY LOW LVL FLOW. AS FOR TEMPS WILL KEEP READINGS MOSTLY IN THE
LOWER TO MID 70S OVER NERN CO ALTHOUGH THE RAP SUGGEST READINGS OVER
THE NERN CORNER MAY STAY IN THE 60S DUE TO EXTENSIVE LOW CLOUDS.
FOR TONIGHT STORMS OVER THE PLAINS WILL LIKELY EVOLVE INTO AN MCS
AND MOVE EASTWARD INTO THE CNTRL HIGH PLAINS THIS WILL HAVE HIGHER
POPS THIS EVENING FROM SOUTH OF AKRON TO LIMON. LATER TONIGHT
ANOTHER DISTURBANCE MAY MOVE ACROSS THE AREA WHICH COULD INCREASE
THE CHC FOR SHOWERS AND A FEW TSTMS AFTER MIDNIGHT. FOR NOW WILL
JUST KEEP POPS IN THE CHC CATEGORY DUE TO UNCERTAINTY WITH TIMING OF
THIS FEATURE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 305 AM MDT THU MAY 22 2014
SOUTHERLY FLOW ALOFT WILL CONTINUE FRIDAY WITH LOWER LEVEL
SOUTHEASTERLY UPSLOPE FLOW. SHOWERS ARE EXPECTED TO BE ONGOING IN
THE MORNING WITH A FEW THUNDERSTORMS POSSIBLE. OVERALL...CAPES
WILL BE LOWER AS UPPER LEVELS WARM SLIGHTLY AND LOWER LEVELS
REMAIN SLIGHTLY COOLER DURING THE DAY AS CLOUD-COVER WILL PREVAIL
THROUGH THE DAY. CAPE VALUES OF 250-700 J/KG ARE EXPECTED OVER THE
DAY...WITH THE HIGHEST VALUES OVER THE EASTERN PLAINS. SLOW STORM
MOTION EXPECTED THAT DAY SO LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY WHERE THE LOW LEVEL UPSLOPE FLOW PUSHES
AGAINST THE FOOTHILLS AND HIGHER TERRAIN. GIVEN THE LOWER CAPES
NEAR THE FOOTHILLS THOUGH...STORMS ARE NOT EXPECTED TO GET THAT
STRONG. WILL STILL BE ON ALERT WITH INCREASED MOISTURE SURGE FROM
THE SOUTH TO WATCH FOR POTENTIAL HEAVY RAIN. COULD SEE SOME SMALL
HAIL ACROSS THE PLAINS.
ACTIVITY WILL LIKELY CONTINUE...ALTHOUGH AT A DECREASED RATE
OVERNIGHT. THE UPPER LOW WILL LIFT NORTHEAST TOWARD THE STATE
SATURDAY WITH SLIGHTLY INCREASED FLOW ALOFT. EXPECT CONTINUED
SHOWERS AND THUNDERSTORMS ACROSS THE AREA WITH LOCALLY HEAVY
RAINFALL AND SMALL HAIL THE MAIN CONCERNS AGAIN AS CAPES REMAIN IN
THE 250-500 J/KG. AN DRIER AREA SHOWN IN ALL MODELS WILL MOVE UP
INTO EASTERN COLORADO SATURDAY NIGHT TO SUBSTANTIALLY DRY
CONDITIONS AND POSSIBLE STOP ALL SHOWER ACTIVITY OVERNIGHT...THE
FIRST TIME IN SEVERAL NIGHTS.
THE UPPER LOW IS PROGGED TO MOVE EAST OVER SOUTHEASTERN COLORADO.
IF THE PREVIOUSLY MENTIONED DRY AREA IS STILL OVER THE AREA...MAY
NOT SEE MUCH ACTIVITY OVER THE PLAINS WHILE THE MOUNTAINS WILL
CONTINUE TO SEE SCATTERED SHOWERS AND THUNDERSTORMS. A COUPLE OF
THE MODELS ARE SHOWING A HEALTHY BAND OF PRECIPITATION FORM ON THE
BACKSIDE OF THE LOW OVER WESTERN COLORADO AND THE MOUNTAINS...WILL
CONTINUE FOLLOWING THIS SOLUTION. THE UPPER LOW WILL THEN MOVE
EAST INTO THE TX/OK PANHANDLES TO ALLOW FOR UPPER RIDGING MONDAY
AND TUESDAY...BRINGING WARMER AND DRIER CONDITIONS. COULD STILL
SEE ISOLATED TO SCATTERED SHOWERS MONDAY WHILE THE SYSTEM MOVES
FURTHER AWAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 305 AM MDT THU MAY 22 2014
SATELLITE SHOWS STRATUS NEAR DIA WITH A HOLE OVER THE AIRPORT SO
FAR. HOWEVER WOULD EXPECT STRATUS TO DVLP IN THE NEXT FEW HOURS.
MEANWHILE THE HRRR AND RAP HAVE VASTLY DIFFERENT SOLUTION WITH
REGARDS TO FOG DEVELOPMENT. THE HRRR HAS NO FOG WHILE THE RAP HAS
DENSE FOG AFFECTING DIA BETWEEN 12Z AND 14Z. AT THIS TIME NOT SURE
WHICH MODEL WILL BE RIGHT SO WILL JUST MENTION A TEMPO GROUP FOR 3-5
MILE VISIBILITIES FOR NOW.
FOR THIS AFTN WILL SEE ANOTHER ROUND OF TSTMS BETWEEN 2 PM AND 5 PM.
STORMS MAY BRING SOME HAIL TO ONE INCH IN DIAMETER ALONG WITH HEAVY
RAINFALL. EXPECT MOST OF THE ACTIVITY WILL MOVE EAST OF DIA BY 5 PM
WITH IMPROVING CONDITIONS BY 6 PM. WINDS SHOULD BECOME ELY BY
MIDDAY AND STAY THAT WAY UNTIL OUTFLOW BOUNDARIES MOVE ACROSS
CAUSING VARIABLE WIND DIRECTIONS. BY THIS EVENING WINDS WILL BECOME
MORE SELY. ANOTHER DISTURBANCE MAY MOVE ACROSS AFTER MIDNIGHT
BRINGING A CHC OF SHOWERS AND POSSIBLY A TSTM. BY 12Z ON FRI COULD
SEE MORE STRATUS AND POSSIBLY SOME FOG.
&&
.HYDROLOGY...
ISSUED AT 305 AM MDT THU MAY 22 2014
STORMS THIS AFTERNOON WILL BE SLOWER MOVING SO THERE WILL BE A
HIGHER POTENTIAL FOR HEAVY RAINFALL IN SOME AREAS WITH UP TO 2
INCHES IN 45 MINUTES OR LESS. THE HEAVIEST RAINFALL WILL STAY OVER
THE PLAINS ALTHOUGH THERE COULD BE SOME SLOW MOVING TSTMS IN THE
FOOTHILLS WHICH COULD PRODUCE UP TO AN INCH OF RAIN IN 30 MINUTES IN
A FEW LOCATIONS.
STILL KEEPING A WATCHFUL EYE ON FRIDAY AND SATURDAY FOR HEAVY
RAINFALL FROM STORMS AS THE MOISTURE SURGE MOVES INTO THE STATE
FROM THE SOUTH. INSTABILITY WILL BE WEAKER BUT STILL EXPECTING
SLOWER MOVING STORMS. UPSLOPE FLOW SEEMS TO BE SLIGHTLY WEAKENING
AND A SURFACE TROUGH MAY ALTER THE UPSLOPE FLOW TO LITTLE OR NONE
AT TIMES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM...KRIEDERMAN
AVIATION...RPK
HYDROLOGY...KRIEDERMAN/RPK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
352 AM CDT THU MAY 22 2014
.DISCUSSION...
306 AM CDT
A QUIET END TO THIS WEEK OFFERS MAINLY ONLY TEMPERATURE FORECAST
CHALLENGES. WHILE THERE ARE SMALL CHANCES OF THUNDERSTORMS FORECAST
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK...THE REGIME FORECAST IS
ONE THAT KEEPS THE PROBABILITY LOW OF ANY HIGH IMPACT WEATHER THROUGH
THE HOLIDAY.
TODAY...
AN UPPER LOW ACROSS EASTERN ONTARIO THIS MORNING WILL CONTINUE TO
USHER A SURFACE COLD FRONT SOUTH FROM CENTRAL ILLINOIS AND INDIANA
TODAY. DAMPENED UPPER RIDGING WILL REMAIN IN PLACE FROM THE SOUTHERN
U.S. THROUGH THE MISSOURI RIVER VALLEY TODAY. WITH A STRONG UPPER
JET BETWEEN THESE TWO UPPER FEATURES...BROAD WEAK ASCENT WITHIN THE
RIGHT ENTRANCE REGION AND A SHEARED SHORT WAVE SHOULD SUPPORT HIGH
CLOUDS TO SPREAD ACROSS THE FORECAST AREA LATE THIS MORNING INTO THE
AFTERNOON. THIS IS LIKELY TO BE THICKER IN THE SOUTHERN FORECAST
AREA AND HAVE INCREASED FORECAST CLOUD COVER MORE SO THERE...BUT AT
LEAST SOME AREA WIDE. TEMPERATURES WILL LIKELY BE EFFECTED SLIGHTLY
BY THIS...ALTHOUGH COOLING WITHIN/AT THE TOP OF THE MIXED LAYER FROM
YESTERDAY WILL BE THE PRIMARY REASON FOR COOLER HIGHS. ONSHORE FLOW
WILL DEVELOP BY MID-MORNING WITH COOLER TEMPERATURES NEAR THE LAKE.
EXPECT THAT THE THERMAL DIFFERENCE BETWEEN DOWNTOWN CHICAGO AND FAR
WESTERN SUBURBS TO BE 10-12 DEGREES...NEAR THE LATE MAY CLIMO NORMAL
WITH ONSHORE FLOW ALL DAY.
TONIGHT THROUGH FRIDAY NIGHT...
A SURFACE HIGH WILL CENTER OVER THE AREA OFFERING LIGHT WIND FLOW.
BY LATE THIS EVENING AND THROUGH THIS PERIOD THERE LOOKS TO BE
LITTLE IN THE WAY OF CLOUDS. ONSHORE FLOW WILL REDEVELOP DURING
FRIDAY KEEPING LAKESIDE AREAS IN THE LOWER 60S OR SO. BOTH NIGHTS
LOOK TO SUPPORT 40S FOR LATE NIGHT LOWS IN THE MOST AREAS...WITH
SOME OF THE COOLER SPOTS REALIZING LOWER 40S ON FRIDAY NIGHT.
THE HOLIDAY WEEKEND INTO NEXT WEEK...
THE MEANDERING UPPER LOW ACROSS THE SOUTHWEST U.S. WILL DRIFT
NORTHEAST AS A RESULT OF BEING DISJOINTED FROM THE STRONGER WESTERLY
JET ACROSS THE U.S./CANADIAN BORDER. SUCH A CLOSED FEATURE IN THAT
PATTERN SEEMS TO MORE OFTEN THAN NOT MOVE SLOWER THAN INITIALLY
DEPICTED BY LONG RANGE GUIDANCE. WARM ADVECTION AND PRECIPITABLE
WATER INCREASE ARE FORECAST TO OCCUR SUNDAY AND MOST DETERMINISTIC
AND ENSEMBLE GUIDANCE HINT AT SOME CHANCE OF PRECIPITATION IN THE
REGION...THOUGH MAINLY NORTHWEST OF THE AREA. THE UPPER RIDGE IS
FORECAST TO RE-AMPLIFY OVER THE AREA ON THE HOLIDAY WITH A WEAK
SURFACE FRONT TO THE NORTH. IF THAT PATTERN WERE TO UNFOLD...THUNDER
CHANCES LOOK MINIMAL OVER THE FORECAST AREA. HAVE DECREASED THE
COVERAGE AND MAGNITUDE OF POPS PROVIDED BY A MODEL/PREVIOUS FORECAST
BLEND FOR THE HOLIDAY AND TUESDAY. THE UPPER LOW OR OPEN WAVE SHOULD
SHIFT EAST DURING THE MIDDLE OF THE WEEK...THOUGH THE 22.00 GFS
ACTUALLY TURNS THIS SOUTHEAST WITH BASICALLY VERY LITTLE PRECIP
CHANCES DURING MIDWEEK. WHILE THAT SEEMS A LITTLE SUSPECT...THE
CHANCES FOR RAIN LOOK SMALL AT THIS DISTANCE.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* NORTHEAST WINDS BY MID MORNING VEERING MORE EASTERLY DURING
AFTN...WITH AT LEAST OCNL SUSTAINED SPEEDS AROUND 10 KT.
RC
//DISCUSSION...UPDATED 06Z...
NO SIGNIFICANT AVIATION IMPACTS OVER THE NEXT 24 TO 30 HOURS UNDER
THE INFLUENCE OF DRY CANADIAN HIGH PRESSURE WITH VFR CONDITIONS
THROUGHOUT. NORTHERLY WINDS ARE EXPECTED TO QUICKLY VEER
NORTHEAST BY MID TO LATE MORNING AT ORD/MDW/GYY WITH LAKE BREEZE
PROBABLY MAKING IT TO DPA IN MID TO LATE AFTERNOON. WINDS AT
ORD/MDW/GYY ARE LIKELY TO VEER MORE TOWARD EAST NORTHEAST OR EAST
BY MID TO LATE AFTERNOON. SUSTAINED SPEEDS AT ORD/MDW COULD AT
LEAST OCCASIONALLY BE AROUND 10 KT. WINDS IN NORTH CENTRAL
ILLINOIS INCLUDING RFD WILL BACK FROM NORTHERLY TO NORTHWEST BY MID
DAY. LIGHT AND VARIABLE WINDS ARE EXPECTED AFTER SUNSET THIS
EVENING AS RIDGE AXIS MOVES OVERHEAD.
RC
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM-HIGH IN WIND TRENDS.
* HIGH IN REMAINING ELEMENTS.
RC
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY AND SATURDAY...VFR.
SUNDAY...SCHC TSRA OVERNIGHT WITH MVFR CIGS PSBL.
MONDAY...CHC TSRA...MVFR CIGS PSBL.
TUESDAY...SCHC TSRA...MVFR CIGS PSBL.
JEE
&&
.MARINE...
301 AM CDT
EXPANSIVE HIGH PRESSURE SPREADING SOUTHEAST FROM THE UPPER MIDWEST
ACROSS THE GREAT LAKES REGION TODAY THROUGH SATURDAY WILL RESULT
IN AN EXTENDED PERIOD OF FAIRLY LIGHT WINDS AND LOW WAVES. WINDS
WILL INITIALLY BE NORTH AND NORTHWEST BUT TREND TOWARD GREATER
VARIABILITY LATER TODAY THROUGH SATURDAY AS THE HIGH BECOMES
PRIMARILY CENTERED OVER LAKE MICHIGAN. WINDS IN THE NEARSHORE
AREAS WILL BE CONTROLLED BY LAKE BREEZE INFLUENCES.
THE HIGH WILL THEN SLIDE EAST SUNDAY AND OFF THE ATLANTIC COAST ON
SUNDAY NIGHT...RESULTING IN INCREASING SOUTHERLY WINDS. AS BROAD
LOW PRESSURE OVER THE PLAINS AND CANADIAN PRAIRIES ON SUNDAY
CONSOLIDATES INTO A LOW CENTER NORTH OF THE LAKES ON
MONDAY...GUSTS COULD REACH UP TO 25 KT FOR A PERIOD LATE SUNDAY
INTO MONDAY DESPITE A VERY WARM AIR MASS MOVING OVER THE LAKE.
WITH THIS WARM AND MOIST AIR MASS WILL ALSO COME AN INCREASING
CHANCE FOR THUNDERSTORMS LATE SUNDAY THROUGH MONDAY EVENING.
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:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
319 AM CDT Thu May 22 2014
.DISCUSSION...
ISSUED 319 AM CDT Thu May 22 2014
SHORT TERM...Today through Saturday
07z/2am surface analysis shows cold front extending from near
Paris to just south of Taylorville. Ahead of the boundary, a
warm/humid airmass persists across southeast Illinois where
dewpoints are in the middle to upper 60s. Meanwhile behind the
front, northerly winds have brought considerably drier air into
much of central Illinois, with dewpoints dropping into the upper
40s and lower 50s north of I-72. Front will continue to sag
southward today, eventually dropping south of the Ohio River by
late afternoon. As a result, cooler and less humid conditions can
be expected with high temps remaining in the 70s. Precip chances
will develop along/ahead of the front this afternoon, but will
remain south of the KILX CWA. The only potential fly in the
ointment will be a weak short-wave currently tracking out of
Colorado. As this feature approaches from the west, a few
showers/storms may spread into the far W/SW CWA this afternoon and
evening. While most models keep central Illinois completely dry
today and tonight, higher-res models such as the RAP and HRRR show
precip associated with the wave moving across central/southern
Iowa and approaching from the west this afternoon. Have therefore
included a slight chance POP along/southwest of a Rushville to
Jacksonville line this afternoon into tonight.
High pressure will build into the southern Great Lakes by the end
of the week, pushing the front even further south/southwest. With
dry N/NE flow around the high, sunny skies will be the rule on
both Friday and Saturday with temperatures in the 70s and low
relative humidity values.
LONG TERM...Sunday through Wednesday
As high slides off to the east, remnants of old frontal boundary
will return northward on Sunday. Models continue to produce some
QPF across the area as the warmer air returns: however, with only
meager forcing along a dissipating boundary and rising upper heights,
think this is overdone. Upper ridge will build in earnest across
the Midwest early next week, leading to temperatures climbing well
into the 80s. Big question will be how fast the ridge breaks down
as cut-off low currently over southern California works its way
eastward. GFS has been the slowest model with this process for the
past few runs and its 00z May 22 solution is no exception.
Meanwhile, ECMWF had previously been faster, but its latest run
has slowed down and now keeps wave west of Illinois until
Wednesday. Given high-amplitude upper ridge in place over the
Midwest, continue to favor a slower solution. Even though both the
GFS and ECMWF delay the arrival of the upper low until mid-week,
both produce QPF across the area on Monday and Tuesday. Given high
upper heights and lack of forcing, think little more than isolated
diurnal convection will fire on either of those two days. As such,
have kept the forecast dry until Wednesday when better forcing
arrives with the approaching upper low.
Barnes
&&
.AVIATION...
ISSUED 1210 AM CDT Thu May 22 2014
Strong to severe thunderstorms have shifted se of central IL TAF
sites by late evening with thunderstorms currently moving ese
toward I-70 in southeast IL. Cold front is just pushing south of
I-72 by midnight and will continue to slowly push southward into
southeast IL overnight keeping isolated to scattered thunderstorms
south of central IL rest of tonight. Any redevelopment of isolated
showers and thunderstorms should stay sw of SPI Thu and will keep
all 5 central IL TAFs dry next 24 hours. Could be some MVFR fog
restrictions at CMI later tonight which received 3.61 inches of
rain during late afternoon and evening hours. Patches of mid level
clouds from 6-12k ft over central IL with broken ceilings possible
next few hours. WSW winds at DEC and CMI should veer NNW next hour
or two as cold frontal zone slips south of these airports. Wind
speeds fairly light through Thu from 5-10 kts.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1231 AM CDT THU MAY 22 2014
.DISCUSSION...
350 PM CDT
MAIN FORECAST CONCERNS ARE WITH STRONG TO SEVERE THUNDERSTORMS IN
THE NEAR TERM...AS WELL AS TEMP TRENDS INTO THE EVENING.
LATEST RADAR IMAGERY DEPICTING RAPID THUNDERSTORM DEVELOPMENT IN
AND AROUND SURFACE TROUGH/COLD FRONT ACROSS EAST CENTRAL ILLINOIS
AND NORTH CENTRAL INDIANA. OUT AHEAD OF THIS FRONT...DEWPOINTS IN
THE MID/UPPER 60S STILL RESIDE AND ARE AIDING IN MODERATE TO
STRONG INSTABILITY. INCREASING SHEAR AND STEEP LOW/MID LEVEL LAPSE
RATES ARE PROVIDING FOR SOME RATHER ROBUST DEVELOPMENT ACROSS THIS
GENERAL AREA...CLIPPING THE FAR SOUTHERN TIER OF COUNTIES...WITH
LARGE HAIL THE PRIMARY THREAT. EXPECT THIS DEVELOPMENT TO REMAIN
CONFINED TO THE CURRENT LOCATION AND SOUTHWARD OVER THE NEXT ONE
TO TWO HOURS...BEFORE THESE THUNDERSTORMS SHIFT SOUTH WITH THE
SOUTHWARD MOVEMENT TO THE FRONT. DONT ANTICIPATE ANY FURTHER
DEVELOPMENT THIS EVENING OVERNIGHT...WITH DRY CONDITIONS EXPECTED
FOR THE CWA OVERNIGHT. TEMPS ARE CURRENTLY STILL WARMING PRETTY
GOOD WITH MID/UPPER 80S OVERHEAD WITH THE EXCEPTION OF COOLER
CONDITIONS NEAR THE LAKE. AS STRONGER PRESSURE GRADIENT TO THE
NORTHWEST CONTINUES TO SHIFT EAST WITH TIME HERE IN THE NEXT
COUPLE OF HOURS...FEEL THAT A SHIFT TO THE NORTHWEST WILL STILL BE
ABLE TO HELP THE LAKE BREEZE TO RETREAT LATE THIS AFTERNOON AND
EVENING AND WITH SOME WARMING STILL POSSIBLE NEAR THE LAKE.
ONGOING COLD ADVECTION WILL CONTINUE OVERNIGHT...AND WITH CLEARING
SKIES AND MUCH DRIER AIR IN PLACE...A COOLER NIGHT IN THE 50S WILL
BE LIKELY.
RATHER QUIET CONDITIONS EXPECTED OVER THE NEXT SEVERAL DAYS AND
EVEN INTO THE WEEKEND...WITH DRY CONDITIONS LIKELY. WEAK COLD
ADVECTION WILL CONTINUE OVER THE NEXT COUPLE OF DAYS WITH COOLER
TEMPERATURES IN THE 70S/60S EXPECTED. BUILDING HIGH PRESSURE FROM
THE NORTHWEST WILL ESTABLISH ITSELF OVERHEAD BY THE END OF THE
WORK WEEK BEFORE SHIFTING TO THE EAST THROUGH THE WEEKEND. THIS
WILL OCCUR AS UPPER LEVEL RIDGING OCCURS ACROSS THE REGION...AND
WHILE WAA BRINGS A RETURN TO WARMER WEATHER. ALTHOUGH WARMER
WEATHER IS EXPECTED NEXT WEEK...IT DOES LOOK UNSETTLED WITH
SHOWER/THUNDERSTORM CHANCES WITH THE RETURN OF A MORE MOIST
ENVIRONMENT.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NORTHEAST WINDS BY MID MORNING VEERING MORE EASTERLY DURING AFTN.
RC
//DISCUSSION...UPDATED 06Z...
NO SIGNIFICANT AVIATION IMPACTS OVER THE NEXT 24 TO 30 HOURS UNDER
THE INFLUENCE OF DRY CANADIAN HIGH PRESSURE WITH VFR CONDITIONS
THROUGHOUT. NORTHERLY WINDS ARE EXPECTED TO QUICKLY VEER
NORTHEAST BY MID TO LATE MORNING AT ORD/MDW/GYY WITH LAKE BREEZE
PROBABLY MAKING IT TO DPA IN MID TO LATE AFTERNOON. WINDS AT
ORD/MDW/GYY ARE LIKELY TO VEER MORE TOWARD EAST NORTHEAST OR EAST
BY MID TO LATE AFTERNOON. SUSTAINED SPEEDS AT ORD/MDW COULD AT
LEAST OCCASIONALLY BE AROUND 10 KT. WINDS IN NORTH CENTRAL
ILLINOIS INCLUDING RFD WILL BACK FROM NORTHERLY TO NORTHWEST BY MID
DAY. LIGHT AND VARIABLE WINDS ARE EXPECTED THIS AFTER SUNSET THIS
EVENING AS RIDGE AXIS MOVES OVERHEAD.
RC
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH IN WIND TRENDS.
RC
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY AND SATURDAY...VFR.
SUNDAY...SCHC TSRA OVERNIGHT WITH MVFR CIGS PSBL.
MONDAY...CHC TSRA...MVFR CIGS PSBL.
TUESDAY...SCHC TSRA...MVFR CIGS PSBL.
JEE
&&
.MARINE...
202 PM CDT
A FAIRLY BROAD AREA OF LOW PRESSURE IS POSITIONED OVER THE WESTERN
GREAT LAKES AND WILL MOVE EASTWARD TONIGHT AND THURSDAY. A COLD
FRONTAL BOUNDARY WILL MOVE ACROSS THE LAKE THIS EVENING WHICH WILL
BRING A STEADIER NORTHWEST WIND AS WELL AS DRIER AIR...WHICH WILL
WORK TO ERODE THE REMAINING FOG ACROSS THE OPEN WATERS LATE THIS
AFTERNOON AND EARLY THIS EVENING. GENERALLY LIGHT NORTHERLY FLOW
WILL REMAIN ACROSS THE LAKE INTO THE WEEKEND AS HIGH PRESSURE MOVES
OVER LAKE MICHIGAN. A SHIFT TO ONSHORE WINDS IS LIKELY THURSDAY AND
FRIDAY...WITH MORE VARIABILITY SATURDAY AS THE HIGH MOVES OVERHEAD.
A SHIFT TO A STEADIER SOUTHERLY WIND IS EXPECTED SATURDAY NIGHT AS
THE HIGH MOVES OFF TO THE EAST. LOW PRESSURE IS FORECAST TO TRACK
NORTHEAST ACROSS THE UPPER MIDWEST SUNDAY NIGHT AND MONDAY WHICH
WILL TIGHTEN THE PRESSURE GRADIENT LEADING TO A BIT OF AN INCREASE
IN WIND SPEEDS BUT STABLE AIR OVER THE LAKE SHOULD KEEP GUST
FREQUENCY LOW.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
1213 AM CDT Thu May 22 2014
.DISCUSSION...
ISSUED 842 PM CDT Wed May 21 2014
The cold front appears to be finally making some progress
southward toward Lincoln, but it is still slow. Conditions are
setting up for an E-W line of storms to fill in ahead of the cold
front, as a shortwave moves northeast along the front. NW flow
aloft will work in conjunction with the low level dynamics to cause
some back-building of the storms to the west. Instability params
look favorable for continued strong to severe thunderstorm
development through at least 10 pm, then we should see some
stabilization of the boundary layer helping to reduce the hail
threat and shift the focus to more heavy rain from training
storms.
The latest severe thunderstorm watch is in affect until 2 am, but
hopefully we can clear most of that watch before midnight. We kept
high chance PoPs across the southern half of our forecast area,
with low chance toward Havana to Bloomington.
After midnight, precip chances should be confined to our far
southern counties as the front approaches the I-70 corridor. Some
clearing in our NW counties late tonight may allow for cooler lows
in the mid 50s, which the forecast handled well already.
The evening updates have been tied to watch issuances and
adjustments, and the latest forecast data are already available.
&&
.AVIATION...
ISSUED 1210 AM CDT Thu May 22 2014
Strong to severe thunderstorms have shifted se of central IL TAF
sites by late evening with thunderstorms currently moving ese
toward I-70 in southeast IL. Cold front is just pushing south of
I-72 by midnight and will continue to slowly push southward into
southeast IL overnight keeping isolated to scattered thunderstorms
south of central IL rest of tonight. Any redevelopment of isolated
showers and thunderstorms should stay sw of SPI Thu and will keep
all 5 central IL TAFs dry next 24 hours. Could be some MVFR fog
restrictions at CMI later tonight which received 3.61 inches of
rain during late afternoon and evening hours. Patches of mid level
clouds from 6-12k ft over central IL with broken ceilings possible
next few hours. WSW winds at DEC and CMI should veer NNW next hour
or two as cold frontal zone slips south of these airports. Wind
speeds fairly light through Thu from 5-10 kts.
07
&&
.PREV DISCUSSION...
ISSUED 158 PM CDT Wed May 21 2014
Severe storm potential will highlight the short term. A brief period
of cooler temps will close out the week, before a long wave ridge
builds into our area for the weekend. As that ridge slides east
later this weekend, a few late afternoon thunderstorms could bubble
up in our western areas on Sunday and Memorial Day as moisture
and heat return to IL.
SHORT TERM...Tonight through Saturday.
The initial severe thunderstorm watch #164 does not include any of
IL, but we still expect some thunderstorms to develop along the
cold front in IL later this afternoon. At 18z/1 pm, the front
extended on a line through Bloomington and Rushville. Surface
dewpoints ahead of the front had climbed into the mid 60s, with
air temps in the mid to upper 80s. Surface based CAPEs were in the
2800-3300 J/kg, with 0-6km wind shear of 35-50kts. LAPS soundings
were indicating little to no cap above the LCL. We should see some
of the storms become strong in our area, with very large hail the
main hazard and damaging winds possible. Supercell formation
appears likely at the onset, with the better chances of linear
progression most likely occurring after the storms advance eastward
into Indiana. The cumulus field on across C IL appears to be
deepening, with some towering cu. A watch may be needed in IL in
the 2-3 pm time frame.
Will maintain high chance PoPs the rest of the afternoon and into
the evening, as coverage could be limited by breaks in the line of
storm cells that develop.
The latest 4km model HRRR output shows rather limited coverage of
storms on an E-W line along and south of I-72, with storms
generally south of our CWA by 06z/1am. Will keep PoPs after
midnight limited to the far southern areas.
The cold front forward progress will slow down and stall near the
southern tip of IL, keeping shower and storm chances close by to
the south and west of our forecast area. We held onto a narrow
area of slight chance PoPs along our far southern counties on
Thurs and Thur night as a result.
Surface high pressure and a building ridge aloft should help keep
our area rain free on Friday and Saturday as moisture return will
be primarily into the Missouri and areas west.
A brief cooler period will occur from Thursday into Friday behind
today`s cold front. Highs will still linger right around normal in
the mid to upper 70s. Saturday will see temps begin a warming
trend, but highs will still remain mainly in the upper 70s.
LONG TERM...Sunday through Wednesday.
Warming through a deeper layer will develop on Sunday as the
surface ridge axis slides east of Illinois and southerly return
flow increases. Low and mid level moisture content will increase as
well, with dewpoints returning to the 60s west of I-55 on Sunday.
Thunderstorm chances will be mainly west of our forecast area, in
the vicinity of a surface trough along the Mississippi river
valley. Instability params support storm progression into western
IL, so we went with low chance and slight chance PoPs west of
I-55. A weakening of the surface trough and increasing cap
strength on Memorial Day may help to diminish storm chances a
little. However, an weak disturbance in the 400-600 mb layer
could cause a few isolated storms. We went with slight chance PoPs
NW of a line from Springfield to Champaign, for mainly late
afternoon/early evening storm potential. Most areas should remain
dry though. Memorial Day looks to be the warmest day of the
holiday weekend, as highs return to the mid 80s. Dewpoints in the
low to mid 60s will make it feel a bit humid outside as well.
On Tuesday and Wednesday, the ECMWF, and to some extent the GFS,
progress an upper low into the ridge, triggering a wider coverage
of showers and storms. Low chance PoPs were included for all our
counties Tuesday and Wednesday to account for the relative
agreement on a wetter solution. Increasing clouds and rain
potential should keep high temps in the 70s both days.
Shimon
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
336 AM CDT THU MAY 22 2014
.SHORT TERM /TODAY/...
ISSUED AT 336 AM CDT THU MAY 22 2014
COMPLEX OF STORMS MOVING THROUGH SOUTHEAST NEBRASKA AND NORTHERN
KANSAS EARLY THIS MORNING. SFC HIGH PRESSURE IS RIDGED THROUGH THE
NORTHERN PLAINS EARLY THIS MORNING AND IS EXPECTED TO SHIFT SOUTH
THROUGH THE DAY WITH DRIER MID LEVEL AIR ARRIVING FROM THE NORTH.
THE PRIMARY CHALLENGE TODAY IS PRECIPITATION CHANCES AND
TEMPERATURES OVER THE SOUTH WHERE CLOUD COVER WILL HAVE AN IMPACT.
THE PRECIPITATION SHOULD REACH THE FAR SOUTHWEST AS THE 850 MB
BOUNDARY LIFTS INTO THAT REGION. SOME KINEMATIC FORCING WILL
OVERRIDE THIS BOUNDARY AND WILL PROVIDE ENOUGH FORCING TO KEEP THE
COMPLEX INTACT IN AT LEAST SOME FORM. THE COMPLEX SHOULD DIMINISH IN
INTENSITY AS IT SHIFTS EAST THROUGH THE MORNING AS A MORE STABLE
AIRMASS WILL BE IN PLACE OVER SOUTHEAST IOWA. HAVE REMAINED
CONSERVATIVE ON POPS AT THIS TIME THOUGH SUSPECT THIS MAY BE TOO LOW
OVER PORTIONS OF THE SOUTH WITH THE INFLUENCE OF THE HIGH PRESSURE
NOT ARRIVING UNTIL LATER IN THE PERIOD. WARMEST TEMPERATURES TODAY
ARE EXPECTED OVER THE NORTH WHERE THE BEST POTENTIAL FOR SUNSHINE
EXISTS.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 336 AM CDT THU MAY 22 2014
LITTLE HAS CHANGED IN FORECAST THINKING FROM PREVIOUS SHIFTS. COOL
AND DRY WEATHER WILL PREVAIL FROM TONIGHT INTO SATURDAY AS A
SURFACE HIGH PRESSURE AREA DOMINATES THE REGION. DURING THE DAY ON
SATURDAY A 500 MB RIDGE AXIS WILL MOVE OVERHEAD AND THE SURFACE
HIGH WILL BEGIN TO MOVE OFF TO THE EAST...BRINGING A RETURN OF
SOUTH SOUTHEAST SURFACE FLOW AND INCREASED MOISTURE ALONG WITH
BROAD BUT WEAK ASCENT ALOFT. THIS SHOULD RESULT IN SOME SHOWERS
AND THUNDERSTORMS MOVING ACROSS THE FORECAST AREA IN A WARM AIR
ADVECTION REGIME BETWEEN SATURDAY AFTERNOON AND SUNDAY EVENING.
WHILE THERE REMAIN DISCREPANCIES IN THE COVERAGE AND TIMING OF
PRECIP...ESPECIALLY WITH A LARGE DRY AIRMASS IN PLACE AHEAD OF
IT...CONFIDENCE IS HIGH IN AT LEAST SCATTERED SHOWERS AND STORMS
AROUND SATURDAY NIGHT AND HAVE INCLUDED 40 TO 60 POPS ACROSS MOST
OF THE AREA TO ACCOUNT FOR THIS.
FROM SUNDAY NIGHT INTO MONDAY 500 MB RIDGING WILL BUILD IN ONCE
AGAIN AND SHOULD PROVIDE A BREAK FROM RAIN ALONG WITH A LITTLE
WARMING...HOWEVER DURING THIS TIME A LARGE 500 MB CUTOFF LOW WILL
BE MOVING FROM THE SOUTHERN INTO THE CENTRAL HIGH PLAINS. THIS LOW
WILL SUBSEQUENTLY STALL OVER KANSAS/MISSOURI/OKLAHOMA/ARKANSAS FOR
MULTIPLE DAYS THROUGH THE MIDDLE OF NEXT WEEK. THIS TRANSLATES TO
A LOT OF 20 TO 40 POPS AS IT IS DIFFICULT TO PIN DOWN ANY GIVEN
FORECAST TIME PERIOD AS BEING PARTICULARLY DRY OR WET...ALTHOUGH
GENERALLY THE BEST RAIN CHANCES SHOULD BE BETWEEN LATE MONDAY AND
LATE TUESDAY WHEN THE 500 MB LOW FIRST APPROACHES. OVERALL WE ARE
LOOKING AT A SOMEWHAT ACTIVE BUT BENIGN EARLY SUMMER PATTERN FOR
MOST OF THE LONG TERM FORECAST...CHARACTERIZED BY MODERATE
TEMPERATURES...INTERMITTENT RAIN CHANCES...AND NO REALLY
SIGNIFICANT STORM SYSTEMS WITH LITTLE THREAT OF SEVERE WEATHER.
&&
.AVIATION...22/06Z
ISSUED AT 1134 PM CDT WED MAY 21 2014
A FEW MINOR CHANGES FROM PREVIOUS PACKAGE. CONVECTION OVER
COLORADO/NEBRASKA EXPECTED TO HOLD TOGETHER AND RIDE ALONG H850
FRONTAL BOUNDARY FROM NORTHERN KS TO NORTHERN MO THROUGH THE
OVERNIGHT HOURS. CURRENT HRRR AND NOW THE 00Z GFS LIFTS THE
WEAKENING AREA OF CONVECTION INTO SW IOWA BY 10Z AND IT DRIFTS
NORTHEAST TOWARD KDSM BY 14Z PRIOR TO WEAKENING THROUGH 18Z. HAVE
INCLUDED VCSH AT 14Z. CONSIDERING MUCAPE IS LESSENING TOWARD
MORNING AS LEFTOVER CONVECTION ENCOUNTERS WEAK MID LEVEL BUBBLE
HIGH OVER IOWA...ANY THUNDER SHOULD BE CONFINED TO THE SOUTHWEST.
OTHERWISE...EARLIER THINKING HOLDS WITH HIGH DRIFTING SOUTH
THROUGH THE DAY AND CLOUDS THINNING TOWARD 00Z./REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1134 PM CDT WED MAY 21 2014
.SYNOPSIS...
ISSUED AT 311 PM CDT WED MAY 21 2014
COLD FRONT JUST SOUTH OF IA WILL CONTINUE TO SINK SLOWLY SOUTH AS
HIGH PRESSURE FROM MANITOBA INTO NEBRASKA PUSHES SOUTHWARD. HIGH
WILL SLIDE SOUTH AND EAST VERY SLOWLY AND WILL BE THE DOMINANT
FEATURE THROUGH THE REST OF THE WORK WEEK. AS IS SLIDES OFF
SAT...THE UPPER LOW IN THE SRN BRANCH OF THE WESTERLIES WILL MOVE
INTO THE CENTRAL U.S. FOR THE SAT-TUE TIME FRAME.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 311 PM CDT WED MAY 21 2014
BENIGN WEATHER IS FORECAST TONIGHT AS A SURFACE HIGH BUILDS INTO
IOWA WITH A NORTHWEST FLOW ALOFT. THE HIGH WILL BRING IN DRIER AIR
TO CENTRAL IOWA. CURRENT OBS HAVE MID 40 DEWPOINTS INTO NW IOWA AND
THAT DRIER AIR WILL WORK ACROSS THE FORECAST AREA TONIGHT. WE WILL
LIKELY NOT SEE MID 40S ACROSS THE SOUTH BUT UPPER 40S TO AROUND 50
ARE LIKELY. THE FRONTAL BOUNDARY THAT MOVED THROUGH LAST NIGHT AND
THIS MORNING WILL STALL OUT AND RESIDE JUST TO THE SOUTH OF IOWA.
VERY WARM MOIST AND UNSTABLE AIR WILL REMAIN JUST TO THE SOUTH OF
IOWA AS A RESULT SO THERE MAY BE SOME CU DEVELOPMENT THROUGH LATE
AFTERNOON BUT BY AND LARGE THE HIGH AND THE DRIER AIR WILL WIN OUT
KEEPING A CLEAR TO MOSTLY CLEAR SKY IN PLACE ALONG WITH COOL TEMPS.
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 311 PM CDT WED MAY 21 2014
HIGH PRESSURE WILL KEEP THE PRECIPITATION TO THE SOUTH AND WEST OF
THE CWA WITH A DRY EASTERLY FLOW THROUGH FRIDAY NIGHT. AS HIGH
MOVES OFF TO THE EAST THE SHOWERS AND THUNDERSTORMS WILL
SPREAD EAST SLOWLY WITH RAIN OVER THE ENTIRE AREA BY SUNDAY NIGHT.
UNSETTLED WEATHER WILL CONTINUE THROUGH TUE AS THE UPPER LOW
ADVANCES INTO THE CENTRAL U.S. TEMPS CLOSE TO MOS VALUES...A
LITTLE LOWER EARLY NEXT WEEK DUE TO THE CLOUDS AND RAINFALL.
&&
.AVIATION...22/06Z
ISSUED AT 1134 PM CDT WED MAY 21 2014
A FEW MINOR CHANGES FROM PREVIOUS PACKAGE. CONVECTION OVER
COLORADO/NEBRASKA EXPECTED TO HOLD TOGETHER AND RIDE ALONG H850
FRONTAL BOUNDARY FROM NORTHERN KS TO NORTHERN MO THROUGH THE
OVERNIGHT HOURS. CURRENT HRRR AND NOW THE 00Z GFS LIFTS THE
WEAKENING AREA OF CONVECTION INTO SW IOWA BY 10Z AND IT DRIFTS
NORTHEAST TOWARD KDSM BY 14Z PRIOR TO WEAKENING THROUGH 18Z. HAVE
INCLUDED VCSH AT 14Z. CONSIDERING MUCAPE IS LESSENING TOWARD
MORNING AS LEFTOVER CONVECTION ENCOUNTERS WEAK MID LEVEL BUBBLE
HIGH OVER IOWA...ANY THUNDER SHOULD BE CONFINED TO THE SOUTHWEST.
OTHERWISE...EARLIER THINKING HOLDS WITH HIGH DRIFTING SOUTH
THROUGH THE DAY AND CLOUDS THINNING TOWARD 00Z./REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MS MAY 14
SHORT TERM...FAB
LONG TERM...MS MAY 14
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
352 AM CDT Thu May 22 2014
...UPDATED SHORT TERM...
.SYNOPSIS...
ISSUED AT 350 AM CDT THU MAY 22 2014
An upper low was moving east into the desert southwest pushing
southerly difluent flow aloft into the southern Rockies. The 00 utc
500 and 700 mb analysis indicated some moisture flux in the mid
levels, but not very impressive at 700 mb across the southern High
Plains. Warm boundary layer air was in place through the entire
southern and central Plains with temperatures at 850 mb at 20 to 25
degrees C. After initial severe thunderstorms fed off the easterly
boundary layer upslope flow across NW and west central Kansas,
additional marginally severe/severe storms developed behind the
previous storms outflow and in a better mid level instability
environment after midnight across Ness Rush and Trego counties,
which approximated the earlier runs of the HRRR model. Radar
estimates following this convection as of around 130 am suggest an
inch to an inch and a half easily could have fallen across
northwest Ness county between Utica and Arnold.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 350 AM CDT THU MAY 22 2014
Convection chances will be the main theme for the next 24 to 36
hours of forecast timeframe. Determining where those will be likely
to redevelop will be better suited for later in the day as the
atmosphere destabilizes again in collocation with the best low level
convergence of the stationary front or old outflow boundaries. Models
indicate precipitation already early in the day, possibly overdone
owing to the mean layer CAPE but not out the plausibility. If
easterly to southeasterly flow redevelops which appears likely,
another round of late afternoon or mainly late evening thunderstorms
is likely for any part of the area as is being shown in recent NMM/ARW
WRF model runs both (00 and 06 UTC runs). These evening MCS trends
were followed for the overall precipitation chance trends late today
and tonight. Model soundings this evening show generally
unidirectional flow rather than very strong low level veering which
would tend to support clusters or weak qlcs type storm structures.
In the meantime, the afternoon should be warm and humid. Most of the
model guidance indicates 80-s to around 90 across the southern
counties. Old convective outflow may moderate the temperature
heating curve from what the models produce.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 236 PM CDT WED MAY 21 2014
Thunderstorm chances will persist through the weekend as medium
range models continue to indicate a closed off upper level low
shifting ever so slowly eastward across the Desert Southwest.
As the system approaches, increased divergence aloft downstream
of the trough axis combined with an upper level jet lifting
northeastward into the Western High Plains will set the stage
for thunderstorm development across portions of central and
western Kansas each day through Sunday. Meanwhile, a prevailing
low level south-southeasterly flow will draw additional moisture
into the state with H85 dewpoints climbing well above 10C by
Sunday. GFS and ECMWF model soundings also show sufficient
instability with SBCAPE values in excess of 1000 to 1500 J/KG
while lapse rates steepen each afternoon through the weekend.
As a result, rain showers and thunderstorms can be expected each
day across parts of western and central Kansas.
Near normal temperatures are likely Friday as slightly cooler air
is cycled back into western Kansas on the backside of a broad
surface high in the Great Lakes Region. The GFS/ECMWF show H85
temperatures ranging from the mid to upper teens(C) across central
Kansas to the upper teens(C) out near the Colorado border. Highs
reaching 80F may be a struggle Friday afternoon with increased
cloud cover likely along with areas of precip. Similar
temperatures are forecast through the weekend with little change
expected to the overall air mass across the high plains of western
Kansas.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1249 AM CDT THU MAY 22 2014
Scattered thunderstorms will continue for a few hours longer along
a low level wind convergence zone in proximity to steep low and
mid level lapse rates and moderate most unstable capes. A few large
cores ca be expected mainly in the vicinity of the HYS terminal
through 9z, which potential could cause strong surface downdrafts.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 87 62 81 61 / 30 60 50 60
GCK 86 60 80 60 / 30 60 50 50
EHA 85 59 80 59 / 40 70 40 40
LBL 87 61 81 61 / 40 70 50 40
HYS 84 61 81 62 / 30 60 60 60
P28 91 65 84 64 / 30 50 50 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Russell
SHORT TERM...Russell
LONG TERM...JJohnson
AVIATION...Russell
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1136 PM MDT WED MAY 21 2014
.UPDATE...
ISSUED AT 1054 PM MDT WED MAY 21 2014
UPDATED GRIDS AND ZONES FOR THE CANCELLATION OF SEVERE
THUNDERSTORM WATCH 170. THE SEVERE THREAT HAS DIMINISHED.
UPDATE ISSUED AT 913 PM MDT WED MAY 21 2014
UPDATED GRIDS AND ZONES FOR A CANCELLATION OF PART OF THE SEVERE
WATCH. EASTERN COLORADO AND PART OF NORTHWEST KANSAS IS NO LONGER
IN THE WATCH. THE WATCH CONTINUES FOR THE EASTERN PART OF THE WATCH.
&&
.SHORT TERM...(THIS AFTERNOON INTO TONIGHT)
ISSUED AT 205 PM MDT WED MAY 21 2014
MAIN CHANGE FOR THIS TIME PERIOD WAS TO SLOW THE ONSET OF
THUNDERSTORM DEVELOPMENT. FRONT WAS DRAPED RATHER FAR SOUTH AND
ALONG THE FRONT RANGE TO THE WEST. AN AREA OF SURFACE CONVERGENCE
EXTENDED FROM KIT CARSON AND CHEYENNE COUNTIES TOWARD THE
NORTHWEST. RATHER STRONG SURFACE WINDS OCCURRING OVER THE AREA AT
THIS TIME. SHORTWAVE TROUGH OVER NEW MEXICO IS EXPECTED TO MOVE
TOWARD THE NORTHEAST THROUGH THE NIGHT WITH A SLUG OF SUBTROPICAL
MOISTURE COMING IN ADVANCE OF IT. ALSO A RIGHT REAR QUADRANT OF
THE JET STARTS OVER THE SOUTHWEST HALF OF THE AREA LATE THIS
AFTERNOON INTO THE EVENING HOURS.
THIS IS ALL STARTING A LITTLE SLOWER THAN WHAT THE EARLIER FORECAST
HAD. AREA RADARS/SATELLITE/LIGHTNING DETECTION SHOW AN AREA/LINE
OF STORMS DEVELOPING FROM SOUTHWEST KANSAS INTO SOUTHEAST COLORADO
TO ALONG THE NORTHERN COLORADO FRONT RANGE. WHERE THE MAIN PROBLEM
IS FOR THIS FORECAST IS THAT THE MODELS DISAGREE ON WHERE TO PUT
THE MAIN SWATCH OF STORMS/QPF. SOME TAKE THE MAIN AREA OVER THE
NORTHWEST HALF...SOME OVER THE SOUTHEAST PORTION CLOSEST TO THE
FRONT AND SOME DO BOTH.
THE HRRR WHICH HAS BEEN DOING WELL RECENTLY HAS TRENDED FROM
TAKING A BROKEN SWATH OF PRECIPITATION FROM SOUTHWEST TO NORTHEAST
ACROSS THE ENTIRE CWA TO THE TWO DIFFERENT AREAS OVER THE SOUTHEAST
AND NORTHWEST. ALSO THE MODELS ARE ALSO INDICATING A COUPLE OF
DIFFERENT WAVES OF PRECIPITATION. ONE THIS EVENING WITH THIS
IN ITAL WAVE AND THEN ANOTHER ONE LATER TONIGHT. ALL IN ALL THERE
LOOKS TO BE SOME KIND OF PRECIPITATION MOVING ACROSS MOST OF THE
AREA...JUST NOT SURE EXACTLY WHERE.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 228 PM MDT WED MAY 21 2014
THE FOCUS/MAIN CONCERNS FOR THE LONG TERM FORECAST PERIOD ARE SEVERE
WEATHER CHANCES AND POTENTIAL FOR HEAVY RAINS. THE PRIMARY TIME FOR
SEVERE WEATHER WITHIN THE LONG-TERM FORECAST RESIDES ON THURSDAY
AND THURSDAY NIGHT. THREAT FOR HEAVY RAINS WILL BE HIGHEST FROM
THURSDAY THROUGH SATURDAY NIGHT.
ON THURSDAY...A LULL IN CONVECTIVE ACTIVITY SEEMS PROBABLE FOR
THURSDAY MORNING BEFORE ACTIVITY ONCE AGAIN RAMPS UP IN THE
AFTERNOON. IN A SIMILAR SCENARIO TO WEDNESDAY...THUNDERSTORMS
DEVELOP TO THE SOUTH AND WEST ALONG A STALLED FRONT...CONVECTIVE
OUTFLOWS AND THE FRONT RANGE. THUNDERSTORMS THEN SPREAD NORTHEAST
ACROSS THE FORECAST AREA. INSTABILITY MAY BE HIGHER THURSDAY
COMPARED TO TODAY...HOWEVER...THE SHEAR SIGNIFICANTLY DECREASES. DO
NOT THINK THE TORNADO OR SUPERCELL THREAT IS AS HIGH FOR THURSDAY
COMPARED TO WEDNESDAY. PULSE-LIKE HAIL STORMS AND CONVECTIVE
CLUSTERS SHOULD BE THE PRIMARY STORM MODES WITH LARGE HAIL AND
DAMAGING WINDS AS THE MAIN THREAT. SOME SIGNIFICANT HAIL AT OR ABOVE
2 INCHES REMAINS POSSIBLE.
FROM THURSDAY NIGHT THROUGH MONDAY...SHOWER AND THUNDERSTORM CHANCES
CONTINUE ACROSS THE FORECAST AREA AS THE UPPER LEVEL LOW REMAINS
OVER THE WESTERN UNITED STATES. HAVE ADVERTISED THE BEST CHANCES FOR
RAIN IN THE AFTERNOON AND EVENING EACH DAY AS SHORTWAVE TROUGHS PASS
THROUGH AND DAYTIME INSTABILITY IS HIGHEST. IT IS POSSIBLE THAT
CONVECTION CONTINUES THROUGHOUT THE NIGHT ON THURSDAY AND POSSIBLY
FRIDAY. THE UPPER LEVEL LOW PRESSURE SYSTEM EJECTS OVER THE PLAINS
MONDAY AND CLEARS OUT TO THE EAST BY TUESDAY. MODELS HAVE SLOWED THE
SYSTEM SLIGHTLY SO HAVE PULLED POPS BACK TO THE WEST SOME.
WITH RESPECT TO POTENTIAL FLASH FLOODING...AGAIN THE HIGHEST
POTENTIAL FOR THIS THREAT IS BETWEEN THURSDAY NIGHT AND SATURDAY
NIGHT. PRECIPITABLE WATER READINGS APPROACH TO EXCEED 2 STANDARD
DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. SEVERAL CLUSTERS WILL
PASS THROUGH WITH HEAVY RAIN RATES AND SUFFICIENT INSTABILITY. STILL
UNSURE ABOUT THIS BECOMING A WIDESPREAD FLOODING EVENT DUE TO
UNCERTAINTY IN EXACT STORM MOVEMENT. IF THERE WERE TO BE FLASH
FLOODING...THE MOST LIKELY LOCATION IS NORTHWEST KANSAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1127 PM MDT WED MAY 21 2014
VFR CONDITIONS ARE EXPECTED FOR PART OF THE NIGHT AT KGLD AND
KMCK WITH STORMS MOVING OUT OF THE AREA. HOWEVER, FORECAST
SOUNDINGS INDICATE STRATUS WILL MOVE INTO THE SITES TOWARD
SUNRISE. THE NAM BOUNDARY LAYER MOISTURE PROG INDICATES THAT HIGH
RH DOES NOT PERSIST VERY LONG AND IS RATHER SPOTTY. THIS CASTS
UNCERTAINTY ON WHETHER THERE WILL BE ANY VISIBILITY RESTRICTIONS
DUE TO FOG. SOME MVFR CONDITIONS ARE POSSIBLE ESPECIALLY AT KMCK
BUT CANNOT RULE IT OUT AT KGLD EITHER. STRATUS WILL DISSIPATE QUICKLY
WITH VFR RETURNING BY MID MORNING. MORE THUNDERSTORMS ARE EXPECTED AT
BOTH SITES THURSDAY AFTERNOON AND EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...FS
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...FS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1157 PM CDT Wed May 21 2014
.UPDATE...
Issued at 1152 PM CDT WED MAY 21 2014
Short range models continue to slow convective development across
north central and northeast KS and have thus delayed POPs and
thunderstorm chances overnight. Still a wide variety of convective
development possibilities from the various short range models and
have not modified forecast beyond tonight due to uncertainty.
&&
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Thursday)
Issued at 311 PM CDT WED MAY 21 2014
Latest surface analysis shows surface trough extending northeast
from a low over the Texas Panhandle to near Topeka then into
northwest Missouri. Dew points have increased to around 66 degrees
to the south of the boundary in east central Kansas. Cu field has
developed along and to the north of the boundary. Convergence was
still weak and capping remains in place as CIN values range from 100
to 200 J/kg at 20Z. 0-6km shear of 40 to 50 kts over the CWA and
shear is forecast to decrease some overnight to around 30 to 40 kts.
Cape was running around 2000-2500 J/kg at late afternoon. If cap is
able to be overcome then isolated thunderstorms could develop and
could become severe with hail and and wind the main Hazards. Have
left small chances for thunderstorms from late afternoon and into
the early evening hours. There does not seem to be any weak waves
that would set anything off. The HRRR and the new 18Z NAM develop
some convection this evening along the frontal boundary and in area
of 850 mb convergence and theta advection. Have increase chances
after 03Z. The next area to watch remains convection moving off the
High Plains and/or developing across south central Kansas. Models
are showing that good moisture transport will focus into central
Kansas by 06Z then veering into northeast Kansas by 12Z with the
increase of the low level jet. Corfidi vectors suggest an eastward
movement to any MCS that would develop out in western Kansas.
Precipitable water values increase to around 1.5 inches along I-70
overnight. Isolated hail and strong winds will be possible with the
MCS as it moves across the state.
Thursday, there still could be some morning convection which will
leave outflow boundaries across the area along with the frontal
boundary. Shear is not as strong as today generally in the
20 to 30 kt range and is less favorable for supercells. There is a
wave that was moving across New Mexico this afternoon that is
progged to be moving into central Kansas on Thursday. Will continue
to keep chance pops going for now. Lows tonight will range from the
lower 60s along the Nebraska border to the upper 60s across east
central Kansas. Highs Thursday will range from the mid 70s in far
northeast Kansas to the mid 80s in east central Kansas.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 311 PM CDT WED MAY 21 2014
The surface front will sag south again Thursday night in wake of
the shortwave trough that will round the upper ridge during the
day Thursday. Proximity of the boundary along with 925-850mb
20-30kt flow moving atop the sfc-850mb boundary could lead to sct
thunderstorms overnight into early Friday. Some low chcs for pops again
Friday although the upper ridge over the area and better low level
focus across western KS suggests chcs are minimal this far east.
Another upper wave will move across the region Friday night into
Saturday so that should bring better chcs for scattered
thunderstorms.
The main upper low will drift into the region Sunday and Monday.
It would appear that Sunday night into Monday would bring the
higher rain chcs as the upper low approaches the area given we
will lack a low level focus both days. The upper low will finally
depart Tuesday so precip chcs will diminish then with a dry
weather expected by mid to late week.
&&
.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1152 PM CDT WED MAY 21 2014
Have delayed thunderstorm chances for TAF sites by a couple hours
due to slower development and movement of upper system. Beyond the
chances for convection tonight into Thur morning, would expect
another round to develop late afternoon or evening. VFR conditions
are expected outside of thundersorms.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GDP
SHORT TERM...53
LONG TERM...Omitt
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1055 PM MDT WED MAY 21 2014
.UPDATE...
ISSUED AT 1054 PM MDT WED MAY 21 2014
UPDATED GRIDS AND ZONES FOR THE CANCELLATION OF SEVERE
THUNDERSTORM WATCH 170. THE SEVERE THREAT HAS DIMINISHED.
UPDATE ISSUED AT 913 PM MDT WED MAY 21 2014
UPDATED GRIDS AND ZONES FOR A CANCELLATION OF PART OF THE SEVERE
WATCH. EASTERN COLORADO AND PART OF NORTHWEST KANSAS IS NO LONGER
IN THE WATCH. THE WATCH CONTINUES FOR THE EASTERN PART OF THE WATCH.
&&
.SHORT TERM...(THIS AFTERNOON INTO TONIGHT)
ISSUED AT 205 PM MDT WED MAY 21 2014
MAIN CHANGE FOR THIS TIME PERIOD WAS TO SLOW THE ONSET OF
THUNDERSTORM DEVELOPMENT. FRONT WAS DRAPED RATHER FAR SOUTH AND
ALONG THE FRONT RANGE TO THE WEST. AN AREA OF SURFACE CONVERGENCE
EXTENDED FROM KIT CARSON AND CHEYENNE COUNTIES TOWARD THE
NORTHWEST. RATHER STRONG SURFACE WINDS OCCURRING OVER THE AREA AT
THIS TIME. SHORTWAVE TROUGH OVER NEW MEXICO IS EXPECTED TO MOVE
TOWARD THE NORTHEAST THROUGH THE NIGHT WITH A SLUG OF SUBTROPICAL
MOISTURE COMING IN ADVANCE OF IT. ALSO A RIGHT REAR QUADRANT OF
THE JET STARTS OVER THE SOUTHWEST HALF OF THE AREA LATE THIS
AFTERNOON INTO THE EVENING HOURS.
THIS IS ALL STARTING A LITTLE SLOWER THAN WHAT THE EARLIER FORECAST
HAD. AREA RADARS/SATELLITE/LIGHTNING DETECTION SHOW AN AREA/LINE
OF STORMS DEVELOPING FROM SOUTHWEST KANSAS INTO SOUTHEAST COLORADO
TO ALONG THE NORTHERN COLORADO FRONT RANGE. WHERE THE MAIN PROBLEM
IS FOR THIS FORECAST IS THAT THE MODELS DISAGREE ON WHERE TO PUT
THE MAIN SWATCH OF STORMS/QPF. SOME TAKE THE MAIN AREA OVER THE
NORTHWEST HALF...SOME OVER THE SOUTHEAST PORTION CLOSEST TO THE
FRONT AND SOME DO BOTH.
THE HRRR WHICH HAS BEEN DOING WELL RECENTLY HAS TRENDED FROM
TAKING A BROKEN SWATH OF PRECIPITATION FROM SOUTHWEST TO NORTHEAST
ACROSS THE ENTIRE CWA TO THE TWO DIFFERENT AREAS OVER THE SOUTHEAST
AND NORTHWEST. ALSO THE MODELS ARE ALSO INDICATING A COUPLE OF
DIFFERENT WAVES OF PRECIPITATION. ONE THIS EVENING WITH THIS
IN ITAL WAVE AND THEN ANOTHER ONE LATER TONIGHT. ALL IN ALL THERE
LOOKS TO BE SOME KIND OF PRECIPITATION MOVING ACROSS MOST OF THE
AREA...JUST NOT SURE EXACTLY WHERE.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 228 PM MDT WED MAY 21 2014
THE FOCUS/MAIN CONCERNS FOR THE LONG TERM FORECAST PERIOD ARE SEVERE
WEATHER CHANCES AND POTENTIAL FOR HEAVY RAINS. THE PRIMARY TIME FOR
SEVERE WEATHER WITHIN THE LONG-TERM FORECAST RESIDES ON THURSDAY
AND THURSDAY NIGHT. THREAT FOR HEAVY RAINS WILL BE HIGHEST FROM
THURSDAY THROUGH SATURDAY NIGHT.
ON THURSDAY...A LULL IN CONVECTIVE ACTIVITY SEEMS PROBABLE FOR
THURSDAY MORNING BEFORE ACTIVITY ONCE AGAIN RAMPS UP IN THE
AFTERNOON. IN A SIMILAR SCENARIO TO WEDNESDAY...THUNDERSTORMS
DEVELOP TO THE SOUTH AND WEST ALONG A STALLED FRONT...CONVECTIVE
OUTFLOWS AND THE FRONT RANGE. THUNDERSTORMS THEN SPREAD NORTHEAST
ACROSS THE FORECAST AREA. INSTABILITY MAY BE HIGHER THURSDAY
COMPARED TO TODAY...HOWEVER...THE SHEAR SIGNIFICANTLY DECREASES. DO
NOT THINK THE TORNADO OR SUPERCELL THREAT IS AS HIGH FOR THURSDAY
COMPARED TO WEDNESDAY. PULSE-LIKE HAIL STORMS AND CONVECTIVE
CLUSTERS SHOULD BE THE PRIMARY STORM MODES WITH LARGE HAIL AND
DAMAGING WINDS AS THE MAIN THREAT. SOME SIGNIFICANT HAIL AT OR ABOVE
2 INCHES REMAINS POSSIBLE.
FROM THURSDAY NIGHT THROUGH MONDAY...SHOWER AND THUNDERSTORM CHANCES
CONTINUE ACROSS THE FORECAST AREA AS THE UPPER LEVEL LOW REMAINS
OVER THE WESTERN UNITED STATES. HAVE ADVERTISED THE BEST CHANCES FOR
RAIN IN THE AFTERNOON AND EVENING EACH DAY AS SHORTWAVE TROUGHS PASS
THROUGH AND DAYTIME INSTABILITY IS HIGHEST. IT IS POSSIBLE THAT
CONVECTION CONTINUES THROUGHOUT THE NIGHT ON THURSDAY AND POSSIBLY
FRIDAY. THE UPPER LEVEL LOW PRESSURE SYSTEM EJECTS OVER THE PLAINS
MONDAY AND CLEARS OUT TO THE EAST BY TUESDAY. MODELS HAVE SLOWED THE
SYSTEM SLIGHTLY SO HAVE PULLED POPS BACK TO THE WEST SOME.
WITH RESPECT TO POTENTIAL FLASH FLOODING...AGAIN THE HIGHEST
POTENTIAL FOR THIS THREAT IS BETWEEN THURSDAY NIGHT AND SATURDAY
NIGHT. PRECIPITABLE WATER READINGS APPROACH TO EXCEED 2 STANDARD
DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. SEVERAL CLUSTERS WILL
PASS THROUGH WITH HEAVY RAIN RATES AND SUFFICIENT INSTABILITY. STILL
UNSURE ABOUT THIS BECOMING A WIDESPREAD FLOODING EVENT DUE TO
UNCERTAINTY IN EXACT STORM MOVEMENT. IF THERE WERE TO BE FLASH
FLOODING...THE MOST LIKELY LOCATION IS NORTHWEST KANSAS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 535 PM MDT WED MAY 21 2014
VFR CONDITIONS DETERIORATE THIS EVENING AT KGLD AND KMCK AS A LINE
OF STORMS MOVES NORTHEAST IMPACTING KGLD AROUND 01Z AND KMCK BY
04Z. DO NOT EXPECT MORE THAN A COUPLE OF HOURS OF THUNDER AT
EITHER SITE. AFTER MIDNIGHT SOME MORE SHOWERS AND STORMS WILL
LINGER NEAR KGLD. FORECAST SOUNDINGS INDICATE POTENTIAL FOR
STRATUS AND MVFR CONDITIONS AT BOTH SITES TOWARD SUNRISE. VFR CONDITIONS
WILL RETURN BY MID MORNING. INSTABILITY WILL BRING CHANCE OF
THUNDERSTORMS AGAIN THURSDAY AFTERNOON TO BOTH SITES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...FS
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...FS
AREA FORECAST DISCUSSION
NWS JACKSON KY
214 AM EDT THU MAY 22 2014
.UPDATE...
ISSUED AT 214 AM EDT THU MAY 22 2014
UPDATED THE FORECAST TO REFLECT THE CANCELLATION OF SEVERE
THUNDERSTORM WATCH 169. ALSO UPDATED THE POP...WEATHER...SKY
COVER...AND QPF GRIDS TO REFLECT RECENT TRENDS IN RADAR DATA. ANOTHER
CLUSTER OF THUNDERSTORMS IS BEARING DOWN ON OUR AREA AND WILL LIKELY
BE MOVING INTO OUR WESTERN COUNTIES IN THE NEXT COUPLE OF HOURS. THE
QUESTION WILL BE WHETHER OR NOT THIS ACTIVITY IS ABLE TO HOLD
TOGETHER AS IT MOVES IN. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR
OUR SOUTHWESTERN COUNTIES THROUGH 5 AM. THE HAZARDOUS WEATHER WAS
ALSO UPDATED TO GET RID OF THE SEVERE THUNDERSTORM WATCH.
UPDATE ISSUED AT 1052 PM EDT WED MAY 21 2014
QUICK UPDATE TO BRING GRIDS IN LINE WITH LATEST TRENDS...OBS. ISSUED
A FLASH FLOOD WATCH EARLIER FOR SEVERAL HOURS FOR OUR SOUTHWESTERN
COUNTIES. COLD POOL BOUNDARY IS CURRENTLY SETTING UP ACROSS OUR
SOUTHWEST. SHORT WAVE IS PASSING THROUGH THE REGION AND MODELS
ADVERTISE A BRIEF PERIOD OF INCREASED H850 WINDS UP AGAINST AND OVER
THE COLD POOL BOUNDARY IN RESPONSE TO APPROACHING SHORT WAVE
DISTURBANCE. BASED ON UPSTREAM RAINFALL RATES AND TOTALS FROM EARLIER
THIS EVENING FELT IT PRUDENT TO ISSUE A WATCH FOR A FEW HOURS AS
SHOWERS AND THUNDERSTORMS WILL LIKELY REDEVELOP ALONG THE NW...SE
ORIENTED COLD POOL BOUNDARY DURING THE NEXT FEW HOURS. ONCE SHORT
WAVE HAS PASSED EAST OF OUR AREA H850 WINDS SHOULD SLACKEN AND THE
FLASH FLOOD THREAT SHOULD DIMINISH.
UPDATE ISSUED AT 750 PM EDT WED MAY 21 2014
DID A QUICK UPDATE TO FINE TUNE THE POP AND WX GRIDS FOCUSING A BIT
MORE ON THE WESTERN PORTION OF THE CWA ARRIVING SHORTLY AFTER 9 PM
AND RUNNING SOUTH BY 11 PM. ALSO TRIED TO CAPTURE SOME OF THE LATE
NIGHT COLD POOL IN THE T AND TD GRIDS USING THE NEWEST CONSSHORT
DATA. ALSO ADDED A STORM TOTAL QPF GRID AND SHIPPED THAT OUT TO THE
WEB. THESE UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 655 PM EDT WED MAY 21 2014
NOW THAT WE ARE UNDER A SEVERE THUNDERSTORM WATCH BOX UNTIL 2 AM EDT
HAVE UPDATED ALL THE GRIDS THROUGH THE NIGHT TO REFLECT THE SEVERE
THREATS AND TIME THE STORM CLUSTERS AS FORECASTED BY THE HRRR. DID
TEMPER THE PROGNOSIS FROM THAT MODEL WITH THE EXISTING GRIDS AND
ALSO THE 18Z NAM12. IT DOES LOOK LIKE COLD POOLS ARE DEVELOPING WITH
THE CURRENT CLUSTERS TO THE NORTH AND THIS SHOULD HELP DRIVE STRONG
TO SEVERE STORMS SOUTH INTO OUR CWA QUICKER. HAVE TIMED THE STORMS
INTO THE JACKSON AREA AROUND 9 PM WITH THEM ARRIVING AN HOUR OR SO ON
EITHER SIDE OF THAT TIME NORTHWEST AND SOUTHEAST OF THE OFFICE. KEPT
IN THE HEAVY RAIN POTENTIAL AND THE HRRR IS NOW SHOWING BETTER
TRAINING POTENTIAL FOR OUR WESTERN COUNTIES THROUGH THE NIGHT. LARGE
HAIL AND GUSTY WINDS ARE STILL THE MAIN THREATS...THOUGH. DO EXPECT
THE SEVERE MODE TO TRANSITION TO A MAINLY DAMAGING WINDS ONE OVER THE
NEXT FEW HOURS. THESE GRID UPDATES AND THE NEW WCN/ZFP/HWO HAVE BEEN
ISSUED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 350 PM EDT WED MAY 21 2014
18Z SFC ANALYSIS SHOWS LOW PRESSURE OVER THE GREAT LAKES WITH A COLD
FRONT EXTENDING SOUTHWEST THROUGH THE NORTHWEST OHIO VALLEY AND INTO
THE MIDDLE OF MISSOURI. SOUTHEAST OF THIS...PLENTY OF FUEL IS
BUILDING FOR CONVECTION IN THE FORM OF DEWPOINTS IN THE LOW TO MID
60S AND TEMPERATURES PUSHING 80 DEGREES. THIS HAS HELPED TO PRIME
EAST KENTUCKY FOR CONVECTION LATER IN THE EVENING AND THROUGH THE
NIGHT. A FEW ROGUE SHOWERS ARE POPPING UP AND DRIFTING EAST THROUGH
THE AREA THIS AFTERNOON...BUT THE MAIN SHOW LATER THIS EVENING WILL
BE ASSOCIATED WITH THE ONGOING STORMS IN OHIO AND INDIANA EITHER
DIRECTLY OR AS A RE-SPAWNED CLUSTER ON AN OUTFLOW BOUNDARY. ON
SATELLITE...THE HIGHER DEBRIS CLOUDS ARE STARTING TO CLEAR FROM THE
EARLIER CONVECTION TO THE NORTH. THIS SHOULD HELP GIVE A FINAL PUSH
TO THE INSTABILITY OVER THE NEXT SEVERAL HOURS...THOUGH LOWER CLOUDS
WILL REMAIN DUE TO THIS HUMID ENVIRONMENT. MEANWHILE...WINDS ARE FROM
THE SOUTHWEST TO WEST AT 10 TO 20 MPH WITH SOME GUSTS TO 25 MPH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH RIDGING RETREATING TO THE
SOUTH TONIGHT IN THE FACE OF A DECENTLY STRONG SHORTWAVE MOVING
THROUGH FAST NORTHWEST FLOW...CROSSING NORTHERN KENTUCKY. THIS FLOW
PATTERN REMAINS IN PLACE INTO THE DAY THURSDAY WITH JUST A SLIGHT
SHIFT TO THE SOUTHWEST WITH THE MID LEVEL ENERGY TRACK. HEIGHT FALLS
WILL ACCOMPANY THIS ADJUSTMENT THROUGH EAST KENTUCKY INTO FRIDAY
MORNING IN CONJUNCTION WITH A SHARPER TROUGH SWEEPING SOUTHEAST
THROUGH THE EASTERN GREAT LAKES. WITH THIS AGREEMENT HAVE MAINLY
FOLLOWED THE GENERAL DETAILS FROM THE CURRENT AND PAST FEW RUNS OF
THE HRRR ALONG WITH SOME NAM12 INFLUENCE.
SENSIBLE WEATHER WILL FEATURE A LIKELY STORMY NIGHT ACROSS THE AREA.
THE HEIGHT FALLS...ENERGY PERTURBANCES AT MID LEVELS...AND A SPEED
MAX AT 500MB KEEPS THE STAGE SET FOR CONVECTIVE REDEVELOPMENT THROUGH
THE NIGHT INTO THURSDAY. INCREASING PWS...TOWARD 1.5 INCHES...THROUGH
THE AREA WILL CONTRIBUTE TO A POTENTIAL FOR HEAVY TO EXCESSIVE
AMOUNTS OF RAIN TONIGHT....ESPECIALLY IF SOLID COLD POOLS DEVELOP
ALONG WITH TRAINING OF CELLS. HOWEVER...CONFIDENCE IN ANY EXACT
SCENARIO REMAINS LOW GIVEN THE DEVELOPING CONVECTION PATTERN AND THE
CHALLENGE OF PREDICTING SUBSEQUENT INITIATION OFF OF THE SOUTHWARD
MOVING OUTFLOW BOUNDARIES. A LACK OF A CAP AND LIS TO -6/CAPES TO
2000 J/KG WILL ALSO MEAN A GOOD POTENTIAL FOR SEVERE WEATHER WITH ANY
ORGANIZED STORMS THIS EVENING AND INTO THE OVERNIGHT...SHOULD PRIOR
CONVECTION NOT STABILIZE THE ENVIRONMENT. HAVE HIT THIS POTENTIAL
HARD IN THE GRIDS...ZONES...AND HWO. AFTER A MILD NIGHT...A BOUNDARY
SHOULD BE LAYING FROM NORTHWEST TO SOUTHEAST ACROSS EAST KENTUCKY
WITH STILL A POTENTIAL FOR STRONG STORMS ACROSS SOUTHWESTERN PARTS
OF THE AREA. HAVE CONTINUED THIS THREAT INTO THE AFTERNOON. THE
BOUNDARY SHOULD WEAKEN AND DRIFT FURTHER SOUTHEAST INTO THE NIGHT
WITH LESS OF A RISK FOR CONVECTION. COOLER TEMPS WILL BE FOUND
THURSDAY NIGHT OVER OUR NORTHEAST WITH MILDER AND MUGGIER CONDITIONS
SOUTHWEST.
USED THE BCCONSSHORT GRIDS AS A STARTING POINT FOR TEMPERATURES...
DEWPOINTS...AND WINDS THROUGH THE FIRST 24 HOURS AND THEN TACKED ON
THE BCCONSALL. MOST ADJUSTMENTS WHERE MADE FOR TERRAIN DIFFERENCES
TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP ON THE HIGH SIDE
OF ALL GUIDANCE...BUT CLOSEST TO THE HIGHER MET NUMBERS TONIGHT AND
THURSDAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 300 PM EDT WED MAY 21 2014
EXTENDED MODELS ARE IN REASONABLE AGREEMENT THROUGH THE PERIOD...BUT
AS USUAL THERE IS BETTER AGREEMENT WITH LARGE SCALE FEATURES THAN
WITH DETAILS. WE START WITH AN UPPER LEVEL DISTURBANCE THAT DROPS
SOUTHEAST THROUGH THE REGION FRIDAY...EFFECTIVELY JUMP STARING A
TEMPORARILY STALLED OUT SFC COLD FRONTAL BOUNDARY AND SWEEPING IT
OUT OF OUR AREA. THEREAFTER UPPER LEVEL RIDGING AND SFC HIGH
PRESSURE WILL BUILD OVER OUR AREA AND PROVIDE US WITH VERY PLEASANT
WEATHER FOR THE UPCOMING WEEKEND.
MODELS DIFFER MORE WITH RETURN FLOW REGIME EARLY NEXT WEEK. WARM
FRONTAL ZONE WILL MOVE BACK TO THE NORTH ACROSS THE AREA MONDAY AND
COULD PROVIDE SOME PRECIPITATION TO EASTERN KENTUCKY. THEREAFTER WE
FIND OURSELVES IN THE WARM SECTOR AND MORE SUMMER LIKE WEATHER UNTIL
THE POTENTIAL ARRIVAL OF A LOW PRESSURE SYSTEM THAT WILL SLOWLY
MEANDER ITS WAY OUT OF THE CENTRAL PLAINS. 0Z ECMWF WANTS TO BRING
THIS SLOW MOVING DISTURBANCE INTO THE HEART OF THE OHIO VALLEY BY
LATE THURSDAY INTO FRIDAY...JUST BEYOND THE FORECAST WINDOW. A MUCH
MORE INCONSISTENT GFS...AND MORE SPECIFICALLY THE 12Z RUN WANTS TO
TAKE THE DISTURBANCE TO THE GULF COAST...WHILE DEVELOPING A MUCH
STRONGER SYSTEM OVER THE OHIO VALLEY FROM ENERGY DROPPING OUT OF
CANADA DURING THAT SME TIME FRAME. PAST RUNS OF THE ECMWF HAVE SHOWN
A TENDENCY TO TAKE THE DISTURBANCE TO THE GULF COAST AS WELL...BUT
HAS NOT SHOWN ANY EVIDENCE OF SUCH A STRONG SYSTEM DROPPING OUT OF
CANADA.
FOR SENSIBLE WEATHER...ATMOSPHERE STABILIZES RAPIDLY EARLY FRIDAY
MORNING. SO ANY SHOWERS THAT MIGHT LINGER ACROSS THE AREA THURSDAY
NIGHT WILL COME TO AN END JUST AS QUICKLY EARLY FRIDAY MORNING. HIGH
PRESSURE AND A PLEASANTLY COOL AIR MASS OVER THE AREA WILL PROVIDE
GREAT WEATHER FOR THE WEEKEND. WEATHER WILL TURN MUGGY AND RELATIVELY
HOT EARLY NEXT WEEK AFTER A WARM FRONT PUNCHES ITS WAY ACROSS OUR
AREA TO THE NORTH. FOR NOW IT APPEARS THE THREAT OF SHOWERS AND
THUNDERSTORMS WILL INCREASE DAILY THROUGH THE REMAINDER OF THE
WEEK...BUT MUCH WILL DEPEND ON THE PATTERN THAT SETS UP AT THE END
OF THE FORECAST WINDOW AND BEYOND. THE ECMWF AND GFS BOTH ADVERTISE
UNSETTLED WEATHER OVER OUR AREA BY THE END OF THE WEEK BUT VIA
DIFFERENT MEANS TO THAT END. AT THIS POINT AND AFTER CONSIDERING THE
TIME OF YEAR THOUGHTS ARE THAT ANYTHING IS POSSIBLE BEYOND TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 810 PM EDT WED MAY 21 2014
CONDITIONS ARE CLINGING TO VFR THROUGH THE AREA...BUT THE CIGS DO
REMAIN NEAR MVFR IN THIS HUMID PRE-STORM ENVIRONMENT. CONVECTION...
STRONG TO SEVERE...IS ON TRACK TO PUSH SOUTH INTO THE FORECAST AREA
OVER THE NEXT SEVERAL HOURS. HAVE FORECASTED THE WORST CONDITIONS FOR
THE WESTERN PORTION OF THE AREA...LOZ AND SME. WHILE TO THE EAST...AT
JKL AND SJS...HAVE KEPT IT A BIT TAMER. EXPECT THE THREAT OF
THUNDERSTORMS AND LOWER CIGS TO LINGER THROUGH THE REMAINDER OF THE
AREA INTO THE MORNING THURSDAY...AND EARLY AFTERNOON TO THE SOUTHWEST.
HOWEVER... CONDITIONS WILL IMPROVE FROM NORTHEAST TO SOUTHWEST AS A
COLD FRONT RETREATS TO THE SOUTHWEST WITH TIME. KEPT THE RISK OF
THUNDER AND THE LOWER CIGS IN FOR SME THE LONGEST. WINDS WILL BE
OCCASIONALLY BREEZY FROM THE WEST SOUTHWEST THROUGH THE EVENING...BUT
WITH STORMS THE GUSTS COULD BE UP TO 40 KTS OR HIGHER IN THE
WEST...THOUGH CLOSER TO 30 KTS IN THE EAST. LIGHTER WEST WINDS...
OUTSIDE OF ANY STORMS...WILL FOLLOW FOR THE REST OF THE NIGHT AND
INTO THE DAY THURSDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 5 AM EDT EARLY THIS MORNING FOR KYZ058-
068-069-079-080-083>087-111-114-116.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...RAY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1146 PM CDT Wed May 21 2014
.UPDATE...
Issued at 1146 PM CDT WED MAY 21 2014
Scattered thunderstorms northeast of the PAH forecast area should
gradually migrate south with the boundary, but HRRR and NAM data
indicate any convection will be isolated to widely scattered at
best. Based on this and radar trends, have backed off pops
overnight with 14 percent southwest to slight chances across the
rest of the area. No other big changes for the overnight.
&&
.SHORT TERM...(Tonight through Friday night)
Issued at 115 PM CDT WED MAY 21 2014
Surface Based CAPEs have risen into the mid 1K J/kg range.
However, H7 Temps aoa 10C across Semo/Wky may cap convection
there. Best chance will occur tonight when boundary settles
southward, but of course diurnal aid to low level destabilization
will be lost then. Will keep close eye upon swody1 SLGT risk zone,
i.e. mainly northern/eastern counties, where boundary threatens
first.
Pops then carry with the boundary tonight thru Fri night, as it
sags southward and westward, in response to falling heights across
the Ohio Valley and ridging displacement southward/westward.
Streamline analysis reveals perturbations will thus rotate counter
clockwise around the southern U.S. high and overtop the boundary,
inducing chc cat pops, best north/east, least south/west.
80s/60s continue to be the rule, although farthest north/east may
experience the low end range around the 80/60 marks.
.LONG TERM...(Saturday through Wednesday)
Issued at 202 PM CDT WED MAY 21 2014
At the beginning of the extended forecast period (7am Saturday),
the preferred deterministic 12z Wednesday model runs of the
GFS/GEM guidance share a similarity of pushing a shortwave
through the western limb of the high amplitude ridge stretching
from the Gulf Coast to Minnesota/Wisconsin. The effective frontal
boundary is already forecast to be well southwest of the WFO PAH
forecast area during this time, but the GEM and GFS suggest that
an inverted trough over Arkansas is developing in advance of the
shortwave moving along the western limb of the ridge. A small
chance for showers and thunderstorms has been placed along the
western limb of the WFO PAH public grids (more likely in the WFO
PAH Fire Weather grids further west), where elevated convection
will be possible during the day on Saturday.
The NWS Weather Prediction Center (WPC) 1159 am Wednesday discussion
suggests a slower evolution of the mean closed low Sunday into
Monday into the Central Plains from the Eastern Rockies. There is
a subtle difference in the meridional position of the closed low
with the GEM guidance (centered closer to NW quarter of KS)
versus the GFS guidance (centered in south central KS/northern OK)
by 18z Monday. The 12z Wednesday GFS Ensemble splits the
difference and had support from the WPC. The main impact for the
WFO PAH forecast area is that with the exception of Saturday, the
interaction between the aforementioned closed low and ridge keeps
rain chances held at bay until late Monday.
By 00z Tuesday, the GFS Ensemble suggests that the central U.S.
closed low begins to open up and become more progressive, as a
western Canadian trough digs into the northwest U.S. With this in
mind, the ridge gets shifted eastward away from the WFO PAH area,
opening up a better moisture trajectory and increased instability
with sharper lapse rates moving in from the West. Therefore, from
basically Monday/Tuesday onward, a small chance of showers and
thunderstorms remains in the remainder of the forecast.
Utilized a blend of the GEM/GFS/SREF/GEFS guidance for sky, wind,
temperature, dew point, QPF, PoPs, etc...for this extended package
issuance.
&&
.AVIATION...
Issued at 1131 PM CDT WED MAY 21 2014
Will keep conditions VFR tonight through Thursday. There is
certainly a chance of convection around. But confidence in timing
and placement is too low to warrant a TS inclusion at this time.
Winds will not be of much concern. SW aob 6-8 kts overnight veering
around as a front slips south into the area (NW to NE, but light)
through Thursday.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...RST
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1237 AM CDT THU MAY 22 2014
.UPDATE...
ISSUED AT 805 PM CDT WED MAY 21 2014
CLOUDS ARE HANGING TOUGH AND NOT EXPECTING ANY ADDITIONAL CLEARING
FROM WHAT HAS ALREADY OCCURRED THIS EVENING. WITH THIS CLOUD
COVER...HAVE BUMPED UP MIN TEMPS A FEW DEGREES AS WELL AS
DEWPOINTS. HAVE REMOVED THE RAIN MENTION FROM THE ARROWHEAD AS
WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 302 PM CDT WED MAY 21 2014
CLOUDS HAVE BEEN VERY SLOW TO DIMINISH OVER THE NORTHLAND TODAY
UNDER COOL NORTHWESTERLY FLOW ALOFT. THEY ARE STARTING TO THIN TO
OUR SOUTHWEST...AND THAT TREND WILL CONTINUE OVERNIGHT. WE DID
INCREASE CLOUDS THIS EVENING FOR MOST AREAS...FOLLOWING CLOSE TO
THE RAP LOW LEVEL MOISTURE FIELDS. THE LATEST RAP ALSO SHOWS
CLOUDS HANGING IN FOR MUCH OF THE NIGHT OVER THE NORTHEAST HALF TO
TWO THIRDS OF THE CWA. WE WILL MONITOR CLOUD TRENDS TONIGHT AND
WE MAY NEED TO BEEF UP CLOUDS AND ADJUST LOWS UP.
WE BUMPED UP CLOUDS A BIT ON THURSDAY AND WENT WITH PARTLY CLOUDY
SKIES. WE THINK THERE COULD BE CLOUDS AROUND EARLY AND WE SHOULD
DEVELOP SOME CU THROUGH THE DAY. AT THE SURFACE...HIGH PRESSURE
WILL BE OVERHEAD BUT TEMPS WILL STILL BE COOL ALOFT.
HIGH PRESSURE WILL CONTINUE TO IMPACT THE REGION AND PROVIDE DRY
CONDITIONS INTO FRIDAY. TEMPERATURES WILL WARM FROM THE SIXTIES
THURSDAY INTO THE SEVENTIES FOR MOST AREAS ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED MAY 21 2014
THE EXTENDED PERIOD FROM FRIDAY NIGHT THROUGH NEXT WEDNESDAY FINALLY
LOOKS TO BE A SUSTAINED PERIOD OF AT OR ABOVE NORMAL TEMPS ACROSS
MOST OF THE REGION. WHILE AREAS NEAR LAKE SUPERIOR WILL LIKELY SEE
RATHER ROBUST LAKE BREEZE FRONTS DURING THE MIDDAY TO EVENING HOURS
SAT-MON TIME FRAME..THE REMAINDER OF THE DULUTH CWA SHOULD SEE HIGH
TEMPS WELL INTO THE 70S..ALONG WITH DEWPOINTS REACHING INTO THE 60S
BY THE MON-WED TIME FRAME.
SURFACE AND MID LEVEL RIDGE AXIS SHOULD BE OVER THE CWA NEAR THE
BEGINNING OF THE PERIOD FRI NIGHT/SAT..BRINGING A COOL MORNING.
HOWEVER..RETURN SOUTH/SOUTHEAST FLOW SHOULD DEVELOP IN MOST AREAS BY
MIDDAY SAT..WITH BEST CHANCES FOR RAIN SHOWERS REMAINING TO OUR WEST
UNTIL LATER IN THE DAY. RATHER ROBUST DIFFERENTIAL HEATING SHOULD
RESULT IN A FAIRLY STRONG LK SUPERIOR LAKE BOUNDARY DURING THE
AFTERNOON..WITH HIGH TEMPS OCCURRING LATE MORNING TO EARLY AFTERNOON
IN THE FAVORED LAKE BREEZE LOCATIONS. GIVEN THAT LOW LEVEL FLOW WILL
LIKELY STILL HAVE SOME EASTERLY COMPONENT..THERE SEEMS TO BE
POTENTIAL FOR ANY LAKE BREEZE BOUNDARY TO PENETRATE RATHER FAR
INLAND BY LATE AFTERNOON SATURDAY..WITH SOME COOLING EFFECT POSSIBLY
NOTED AS FAR WEST AS THE GRAND RAPIDS/IRON RANGE/INTERIOR ARROWHEAD
AREAS BY EVENING.
CHANCES FOR SHOWERS/TSTORMS WILL INCREASE FROM WEST TO EAST LATE SAT
INTO MONDAY AS NORTHERN STREAM WAVE PUSHES A WEAK FRONT INTO THE NE
MN AREA..BEFORE THE FRONT STALLS AND/OR WASHES OUT EARLY NEXT WEEK.
THE LARGE SOUTHERN STREAM UPPER LOW TRAVERSING THE PLAINS STATES TO
OUR SOUTH DURING THIS TIME AND PRECIPITATION/DEEP CONVECTION
ASSOCIATED WITH IT MAY ACT TO LESSEN THE NORTHWARD LOW LEVEL
MOISTURE TRANSPORT. HOWEVER..SUFFICIENT MOISTURE IS EXPECTED TO BE
IN PLACE TO SUPPORT SOME SHOWERS/STORMS IN VICINITY OF THE LINGERING
BOUNDARY FROM SAT NIGHT INTO MONDAY. AT THIS TIME..IT APPEARS THAT
INSTABILITY AND ESPECIALLY WIND SHEAR/FLOW WILL BE TOO WEAK TO
SUPPORT MUCH IN THE WAY OF ANY SEVERE WEATHER POTENTIAL. AGAIN..WE
EXPECT A LK SUPERIOR LAKE BREEZE FRONT TO DEVELOP SUN-MON AS
WELL..RESULTING IN LATE MORNING/EARLY AFTERNOON HIGH TEMPS IN AREAS
NEAR THE LAKE.
BY MID WEEK..A RATHER SIGNIFICANT LARGE SCALE PATTERN SHIFT TO A
PACNW UPPER TROF AND BROAD WSW MID LEVEL FLOW FROM THE GREAT BASIN
TO MANITOBA/NW ONTARIO SHOULD RESULT IN THE BUILDING OF A LOW LEVEL
THERMAL RIDGE FROM THE DAKOTAS INTO NW MINNESOTA. WHILE THE BEST
FLOW AND SHEAR AS WELL AS INSTABILITY AXIS IS EXPECTED TO REMAIN TO
OUR WEST BASED ON CURRENT GUIDANCE..THERE WILL STILL BE POTENTIAL FOR
SOME ELEVATED STORMS WITHIN THE LOW LEVEL WARM/MOIST ADVECTIVE ZONE
JUST DOWNSTREAM FROM THE MAIN UPPER LEVEL RIDGE AXIS ACROSS THE
DULUTH CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1233 AM CDT THU MAY 22 2014
AN AREA OF MVFR CIGS WILL HOVER OVER THE MN ARROWHEAD OVERNIGHT
AND MAINLY AFECT THE INL AREA. SCT-BKN CIGS OVR KHIB AND KDLH BUT
MAINLY FROM BKN-OVC040-050. CIGS OVR THE AREA WILL BE ALL VFR AFT
14Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 43 69 49 71 / 0 0 0 10
INL 40 73 51 78 / 0 10 10 20
BRD 43 75 54 77 / 0 10 10 10
HYR 39 73 49 76 / 0 0 0 10
ASX 39 68 46 72 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...GSF
SHORT TERM...MELDE
LONG TERM...MILLER
AVIATION...CLC
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1207 AM CDT Thu May 22 2014
.SHORT TERM...(This Evening through Thursday Night)
Issued at 305 PM CDT WED MAY 21 2014
The focus through the period continues to be on thunderstorms
chances. For this afternoon the frontal boundary currently slowly
moving south across portions of the NRN CWA should serve as the
focus for isolated to scattered storms. Dprog/Dt of the HRRR paints
a narrow zone of storms along the front forming by 5 to 6 pm in our
CWA, then they move east and clear the CWA by around 9 or 10 pm.
Latest ACARS soundings out of KMCI depict the CAP slowly eroding so
confidence is rather high we should see a few storms along the
front. Given the large CAPE and modest shear profiles large hail
and damaging winds will be the main threats.
Late overnight tonight a large complex of storms may work into the
CWA from the west/southwest. At this time the better chances of
seeing storms appears to favor the WRN and NRN areas of the CWA.
The complex of storms should be weakening as they move in, thus the
overnight SVR potential is rather low.
Tomorrow most of the CWA will be north of the surface front so high
temps should be back down to near normal... mid to upper 70s with
mid 80s across our far SRN zones. Precip wise is a tough call depending
on how long any overnight activity lingers into the daylight morning
hours, residual cloud debris and degree of instability. So for now
just have low chance pops through tomorrow into tomorrow evening
given a lack upper level forcing.
.LONG TERM...(Friday through Wednesday)
Issued at 305 PM CDT WED MAY 21 2014
A rather messy short to medium range forecast through the Memorial
Day holiday and into much of next week. Why? The development of
the cutoff low across the southwestern United States that will
slowly crawl eastward into early next week. This low is expected to
pull increasing amounts of low-mid level moisture northward into the
Plains which will interact with a stalled frontal boundary in the
region.
By Friday morning, precipitation chances will increase briefly as a
secondary shortwave drops through the Great Lakes and a brief window
of warm advection commences overnight. This upper trough will push surface
high pressure into the region, and force the stalled front well
south of the area, potentially forcing precip south and east of the
CWA Friday afternoon and evening.
It`s hard to get too specific on forecast details through this
weekend and into Monday due to shortwave timing issues. The weekend
shouldn`t be a washout, but we`ll have to carry scattered PoP
wording through Monday.
Medium range models are all over the place in the eventual track of
the upper low through the area through Thursday. ECMWF/GEM produces
fairly widespread rains for Monday and Tuesday with a northern track,
GFS dives the ejecting low too far south to produce widespread rains,
but more scattered activity. Ensemble approach provides little
benefit, with a substantial spread in solutions. For now, have to
continue to include PoPs through much of the extended.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1207 AM CDT WED MAY 21 2014
The main concern for aviators this TAF cycle will be the potential
for showers and thunderstorm during the 11Z-15Z time period. Current
thunderstorms over western Kansas will move eastward overnight moving
into the terminals around sunrise. These storms however will be
diminishing as they progress into the area so have cont to use VCTS
for timing these storms into the terminals because there is some
concern they may not hold together long enough to make it into
western Missouri. Otherwise conds will remain VFR with bkn clouds
between 4-5kft through mid morning tomorrow before scattering. There
will be another chance for thunderstorm during the evening hours
however potential seems to low for inclusion at this point. Winds
will be lgt and vrb overnight before picking up out of the ENE
tomorrow morning between 5-10kts.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Pietrycha
LONG TERM...Dux
AVIATION...73
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1125 PM CDT Wed May 21 2014
.SHORT TERM: (Through Late Tonight)
Issued at 1256 PM CDT Wed May 21 2014
Cold front extended from just north of UIN southwest through MCI.
This front will move southward through our forecast area tonight, and
should extend from west central MO southeast through southern IL by
12z Thursday. The cap should break late this afternoon with
scattered convection developing along this front. The HRRR model
has most of the convection across northeast MO and west central IL
early this evening, then shifts it southward with most of the
convection from around COU east through the St Louis metro area to
Vandalia and Salem IL by midnight. Some of these storms may be
severe due to very unstable conditions late this afternoon and this
evening with CAPEs of 2000-3000 J/Kg and surface LI values as low as
-10 south of the cold front. Low-mid level shear will also be
relatively strong with 500 mb wind speeds of up to 50 kts due to a
500 mb wind max moving through the Great Lakes region.
GKS
.LONG TERM: (Thursday through Next Wednesday)
Issued at 340 PM CDT Wed May 21 2014
The cold front will continue to sag slowly southward as a surface
ridge shifts eastward from the northern Plains into the Great Lakes
region. At least scattered convection is expected along and just
behind this front as weak shortwaves move east southeastward through
our area over the mid-upper level ridge centered over the Gulf Coast
states. The best coverage of convection should be across central
and southeast MO Thursday and Thursday night as the front becomes
more nw to se oriented. The ECMWF model appears to be a little too
far north with its qpf from Thursday afternoon into Friday morning.
Cooler and drier air will advect into the region behind the cold
front, particularly across northeast MO and west central IL.
The mid-upper level low now over NV will move slowly through the
southwest US. Weak shortwaves will eject northeastward from this
feature and bring more convection mainly to the western portion of
our forecast area Saturday and Saturday night with the upper level
ridge along with the surface ridge centered over the Great Lakes and
Ohio Valley regions keeping the eastern portion of our forecast area
dry. The mid-upper level low will eventually move into the Plains
by Monday. The models have varying solutions after this with the
ECMWF model moving it into MO by Tuesday, while the GFS model
weakens it and has it passing south of our area. With this model
uncertainty will just include chance pops for early next week,
although there may be more widespread showers/storms for Monday
night and Tuesday. Always difficult to forecast the exact path,
strength and speed of upper level lows coming out of the southwest
US.
GKS
&&
.AVIATION: (For the 06z TAFs through 06z Thursday Night)
Issued at 1124 PM CDT Wed May 21 2014
Thunderstorms have diminished from earlier this evening leaving
just a few lingering showers over west central Illinois. Cold
front is now between KUIN and KCOU and the St. Louis metro TAF
sites. It will continue to move south the next few hours before
stalling overnight into Friday over southern and western Missouri.
Expect mainly dry and VFR conditions during this TAF period with
north to northeast winds to the north of the cold front. The only
exception may be at KCOU tomorrow afternoon and evening when
scattered thunderstorm may develop close enough to the airport
that they could affect the terminal. Confidence in this scenario
is not high enough to even mention VCTS at this point.
Specifics for KSTL:
Expect dry and VFR conditions through the TAF period.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
459 AM CDT THU MAY 22 2014
.UPDATE...
ISSUED AT 459 AM CDT THU MAY 22 2014
ALREADY SENDING AN UPDATE TO ACCOUNT FOR THE LIFT GENERATING NEW
SHWRS BETWEEN MCK-IML-AKO. THE PUB/GLD RADARS SHOW 25-30 KTS FROM
THE SW AT 5K FT AGL. THE NAM/GFS DO INDICATE ISENTROPIC LIFT WHERE
THESE SHWRS ARE DEVELOPING. NOT SURE HOW MUCH OF THIS WILL HEAD E
INTO THE FCST AREA. SO POPS HAVE BEEN INCREASED THIS MORNING AND
ANTICIPATE FURTHER SHORT-TERM ADJUSTMENTS AS THE MORNING PROCEEDS.
IRONICALLY I USED THE 06Z NAM AS A GUIDE. IF THE NAM TURNS OUT
CORRECT...MAJOR FCST ADJUSTMENTS WILL BE NEEDED LATER THIS
MORNING. WE HAVE NOTED SEVERAL MODELS CAP HIGH TEMPS IN THE UPPER
60S OVER MUCH OF S-CNTRL NEB.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT THU MAY 22 2014
...A DIFFICULT FCST THRU TONIGHT WITH BELOW AVERAGE CONFIDENCE
DUE TO POOR MODEL HANDLING OF THE PLETHORA OF MESOSCALE ASPECTS...
ALOFT: THE LONGWAVES ARE ESSENTIALLY STAGNANT OVER THE CONUS. A
588 SUB-TROPICAL HIGH WAS OVER THE GULF COAST STATES AND WILL
REMAIN THERE THRU TONIGHT. ITS RIDGE AXIS WILL CONT TO EXTEND NW
ACROSS THE CNTRL PLAINS TO MT. THE CUT-OFF LOW OVER NV/CA WILL
MEANDER FURTHER S INTO AZ TONIGHT.
SURFACE: A COOL FRONT REMAINS STALLED W-E ACROSS KS AND WILL
REMAIN IN PLACE THRU AT LEAST TONIGHT. OVERNIGHT TSTM ACTIVITY
WILL STRENGTHEN THE FRONT TODAY. NRN PLAINS HIGH PRES WILL DRIFT
INTO THE WRN GREAT LAKES.
REST OF THIS MORNING: TSTM CLUSTERS WILL CONT EXITING INTO ERN
NEB/KS. CANT COMPLETELY RULE OUT A COUPLE MORE ISOLATED SHWRS/
TSTMS FROM DEVELOPING...BUT THE OVERALL TREND SHOULD BE DRIER.
THIS AGREES WITH THE 03Z HRRR AND 00Z HI-RES WRF RUNS.
QUIET SYNOPTIC REGIMES SUCH AS THIS CREATE MAJOR HEADACHES FOR
FCSTRS. A LOT OF IT COMES DOWN TO INTUITION AS MECHANISMS TO
TRIGGER TSTMS ARE SUBTLE. BUST POTENTIAL IS AT EVERY CORNER FOR
TEMPS/SKY/PRECIP.
TODAY: MOSTLY CLOUDY THIS MORNING WITH LOTS OF CLOUD DEBRIS
AROUND ...BUT IR SATELLITE SHOWS A CLEARING LINE ADVANCING UP FROM
THE TX PANHANDLE. THE TIME-OF-ARRIVAL TOOL BRINGS IT TO OUR SW
COUNTIES BY 830 AM AND TO OUR NE COUNTIES BY 130 PM. SO SKIES
SHOULD TURN PARTLY CLOUDY IF NOT MOSTLY SUNNY THIS AFTERNOON. THIS
BARRING ANY STRATUS THAT MIGHT FORM IN THE PREDAWN HOURS.
BEFORE THE TSTMS FIRED YESTERDAY AFTERNOON...WATER VAPOR IMAGERY
SHOWED WHAT APPEARED TO BE A SHORTWAVE TROF LIFTING FROM NM INTO
THE CNTRL PLAINS. THIS TROF SHOULD ROUND THE RIDGE WITH SUBSIDENCE
TO FOLLOW TODAY. THIS IS PROBABLY WHAT WE ARE SEEING WITH THAT
CLEARING LINE IN SATELLITE.
THE 00Z/06Z NAM CONVECTIVE SCHEMES RE-FIRE TSTMS BY MIDDAY
TODAY...BASICALLY AS SOON AS THE CONVECTIVE TEMP IS REACHED. I
JUST CANNOT SEE THAT HAPPENING IN THE WAKE OF THE DEPARTING TROF.
WOULD EXPECT SOME SUBSIDENCE INVERSION TO RESULT IN AT LEAST A
MODEST CAP. SO THE FCST IS DRY UNTIL 5PM WHEN SLIGHT CHANCE POPS
WERE BROUGHT INTO OUR N-CNTRL KS COUNTIES. HAVE FOLLOWED THE 00Z
WRF RUNS FROM THE NAM... THE NSSL WRF AND THE 07Z/08Z 13 KM RAP
WHICH DO NOT REFIRE CONVECTION.
OTHER MESOSCALE DETAILS: WITH THE HIGH DRIFTING FURTHER E...THE
E-W ORIENTED BAND OF RICH 850 MB MOISTURE ALONG THE FRONT WILL
BEGIN CIRCULATING NW...LIFTING INTO NEB. HOWEVER...SURFACE
DEWPOINTS UPSTREAM OVER IA WERE STILL IN THE MID 40S. SO WHILE IN
SITU DEWPOINTS HAVE RISEN OVERNIGHT...VERY LOW-LEVEL DRY AIR
ADVECTION WILL BE OCCURRING.
ISOLATED TSTMS COULD FIRE ALONG THE CONVECTIVELY REINFORCED WARM
FRONT OVER KS. THIS ACTIVITY COULD LIFT INTO OUR N-CNTRL KS
COUNTIES AND THIS IS WHAT IS FCST BY THE NON-HYDROSTATIC MODELS.
NAM PV IMAGES SHOW A SUBTLE SHORTWAVE TROF EMBEDDED IN THE DRY
SLOT CURRENTLY OVER AZ. MOVEMENT IS NNE AND IT IS FCST TO LIFT
ACROSS NM AND INTO CO TONIGHT. THIS SHOULD TRIGGER THE TSTMS LATE
THIS AFTERNOON AND EVENING OVER THE HIGH PLAINS. WE THEN
ANTICIPATE THIS ACTIVITY TO THREATEN OR MOVE INTO THE FCST AREA
FROM THE SW AGAIN TONIGHT. NO GUARANTEES ON THIS THOUGH. SEVERAL
NON-HYDROSTATIC MODELS KEEP THE FCST AREA DRY. SO POPS WERE KEPT
LOW.
TONIGHT: INCREASING CLOUDS WITH A CHANCE OF SHWRS/TSTMS. GREATEST
CHANCE S AND W OF THE TRI-CITIES. EFFECTIVE SHEAR WILL BE AROUND
30 KTS. WHILE AN ISOLATED SEVERE TSTM IS POSSIBLE OVER N-CNTRL KS
BEFORE MIDNIGHT...IT IS LARGELY BASED ON "IF" TSTMS OCCUR AT ALL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 417 AM CDT THU MAY 22 2014
GUIDANCE SUGGESTS A CLOSED UPPER TROPOSPHERIC LOW WILL EXIST OVER
THE SOUTHWESTERN CONUS AT 12Z FRIDAY. THIS CLOSED LOW IS THEN
EXPECTED TO DRIFT TO THE NORTHEAST AND WEAKEN...EVENTUALLY MOVING
OVER THE CENTRAL PLAINS AS AN OPEN WAVE BY EARLY NEXT WEEK. AT THE
SURFACE SOUTH OR SOUTHEASTERLY FLOW IS EXPECTED TO PERSIST ACROSS
THE AREA THROUGH MUCH OF THE LONG TERM FORECAST PERIOD.
UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE SOUTHWESTERN
UPPER TROPOSPHERIC CLOSED LOW...ALONG WITH MULTIPLE SUBTLE UPPER
TROPOSPHERIC PERTURBATIONS EJECTING FROM THE SOUTHWESTERN
CONUS...WILL CONTINUE TO PROMOTE CHANCES FOR PRECIPITATION ACROSS
THE CWA MOST EVERY DAY DURING THE LONG TERM FORECAST PERIOD. WENT
AHEAD AND TOOK AN EVEN BLEND OF NAM...OPERATIONAL GFS...EC...SREF-
MEAN AND WPC GUIDANCE TO DERIVE QPF GRIDS BOTH FRIDAY AND
SATURDAY...AND THEN DERIVED THE POP GRIDS FROM THESE QPF GRIDS.
AFTER ALL WAS SAID AND DONE...VERY LITTLE CHANGE WAS MADE TO THE
GOING FORECAST. OVERALL...30-60% POPS REMAIN INTACT FOR THE MOST
PART ACROSS THE CWA FRIDAY THROUGH SATURDAY NIGHT. SUNDAY AND
BEYOND...ALLBLEND PROVIDED 20-60% POPS TO VARIOUS PORTIONS OF THE
CWA DURING THE LONG TERM FORECAST PERIOD. THESE POPS WERE LEFT
UNCHANGED FOR THE MOST PART.
CONTINUED SOUTH/SOUTHEASTERLY LOWER TROPOSPHERIC FLOW SHOULD KEEP
INCREASED VALUES OF LOWER TROPOSPHERIC MOISTURE INTACT ACROSS THE
AREA THROUGH EARLY TO MID NEXT WEEK...THUS RESULTING IN 1000-
3000J/KG OF POTENTIAL INSTABILITY EACH AFTERNOON AND EVENING.
ALTHOUGH DEEP-LAYER BULK SHEAR WONT BE ANYTHING TO GET EXCITED
ABOUT...THE MAGNITUDE OF POTENTIAL INSTABILITY ALONE COULD BE
ENOUGH TO PROMOTE STRONG UPDRAFT PRODUCTION CAPABLE OF RESPECTABLE
HAIL SIZE AND PERHAPS DOWN-BURST WIND. THE INHERITED HWO ALREADY
HAD A MENTION OF STRONG STORMS EACH AFTERNOON AND EVENING AND AT
THIS TIME THERE REALLY IS NO REASON TO CHANGE THIS. AS A
RESULT...WENT AHEAD AND MENTIONED THE POSSIBILITY OF STRONG
THUNDERSTORMS EACH AFTERNOON AND EVENING FRIDAY THROUGH NEXT
WEDNESDAY.
LITTLE IF ANY CHANGE IN THE LOWER TROPOSPHERIC AIR MASS WILL
PRESENT SIMILAR TEMPERATURE READINGS FROM DAY TO DAY DURING THE
LONG TERM FORECAST PERIOD...WITH HIGHS GENERALLY IN THE 70S AND
80S AND LOWS IN THE 50S AND 60S CURRENTLY FORECAST.
&&
.AVIATION...(FOR THE 06Z GRI TAF THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1232 AM CDT THU MAY 22 2014
REST OF TONIGHT: MULTI-LAYERED VFR CLOUDS WILL INVADE AND DESCEND
WITH MVFR RAIN MOVING IN BY 08Z. CANT RULE OUT SOME THUNDER BUT
WILL AMEND THE TAF TO INCLUDE TSRA IF TRENDS WARRANT. WINDS WILL
REMAIN NE-ENE BELOW 10 KTS. CONFIDENCE: HIGH
THU: RAIN WILL END PRIOR TO DAYBREAK LEAVING VFR CONDITIONS. MOST
OF THE DAY SHOULD BE DRY. NOT SURE EXACTLY WHEN OR IF TSTMS WILL
REDEVELOP AS A FORCING MECHANISM IS LACKING. WINDS WILL SHIFT TO
THE E AROUND 10 KTS. CONFIDENCE: MEDIUM
THU EVE: VFR BUT THERE IS A CHANCE SHWRS/TSTMS COULD MOVE IN.
CONFIDENCE: LOW
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB 459
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
417 AM CDT THU MAY 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT THU MAY 22 2014
...A DIFFICULT FCST THRU TONIGHT WITH BELOW AVERAGE CONFIDENCE
DUE TO POOR MODEL HANDLING OF THE PLETHORA OF MESOSCALE ASPECTS...
ALOFT: THE LONGWAVES ARE ESSENTIALLY STAGNANT OVER THE CONUS. A
588 SUB-TROPICAL HIGH WAS OVER THE GULF COAST STATES AND WILL
REMAIN THERE THRU TONIGHT. ITS RIDGE AXIS WILL CONT TO EXTEND NW
ACROSS THE CNTRL PLAINS TO MT. THE CUT-OFF LOW OVER NV/CA WILL
MEANDER FURTHER S INTO AZ TONIGHT.
SURFACE: A COOL FRONT REMAINS STALLED W-E ACROSS KS AND WILL
REMAIN IN PLACE THRU AT LEAST TONIGHT. OVERNIGHT TSTM ACTIVITY
WILL STRENGTHEN THE FRONT TODAY. NRN PLAINS HIGH PRES WILL DRIFT
INTO THE WRN GREAT LAKES.
REST OF THIS MORNING: TSTM CLUSTERS WILL CONT EXITING INTO ERN
NEB/KS. CANT COMPLETELY RULE OUT A COUPLE MORE ISOLATED SHWRS/
TSTMS FROM DEVELOPING...BUT THE OVERALL TREND SHOULD BE DRIER.
THIS AGREES WITH THE 03Z HRRR AND 00Z HI-RES WRF RUNS.
QUIET SYNOPTIC REGIMES SUCH AS THIS CREATE MAJOR HEADACHES FOR
FCSTRS. A LOT OF IT COMES DOWN TO INTUITION AS MECHANISMS TO
TRIGGER TSTMS ARE SUBTLE. BUST POTENTIAL IS AT EVERY CORNER FOR
TEMPS/SKY/PRECIP.
TODAY: MOSTLY CLOUDY THIS MORNING WITH LOTS OF CLOUD DEBRIS
AROUND ...BUT IR SATELLITE SHOWS A CLEARING LINE ADVANCING UP FROM
THE TX PANHANDLE. THE TIME-OF-ARRIVAL TOOL BRINGS IT TO OUR SW
COUNTIES BY 830 AM AND TO OUR NE COUNTIES BY 130 PM. SO SKIES
SHOULD TURN PARTLY CLOUDY IF NOT MOSTLY SUNNY THIS AFTERNOON. THIS
BARRING ANY STRATUS THAT MIGHT FORM IN THE PREDAWN HOURS.
BEFORE THE TSTMS FIRED YESTERDAY AFTERNOON...WATER VAPOR IMAGERY
SHOWED WHAT APPEARED TO BE A SHORTWAVE TROF LIFTING FROM NM INTO
THE CNTRL PLAINS. THIS TROF SHOULD ROUND THE RIDGE WITH SUBSIDENCE
TO FOLLOW TODAY. THIS IS PROBABLY WHAT WE ARE SEEING WITH THAT
CLEARING LINE IN SATELLITE.
THE 00Z/06Z NAM CONVECTIVE SCHEMES RE-FIRE TSTMS BY MIDDAY
TODAY...BASICALLY AS SOON AS THE CONVECTIVE TEMP IS REACHED. I
JUST CANNOT SEE THAT HAPPENING IN THE WAKE OF THE DEPARTING TROF.
WOULD EXPECT SOME SUBSIDENCE INVERSION TO RESULT IN AT LEAST A
MODEST CAP. SO THE FCST IS DRY UNTIL 5PM WHEN SLIGHT CHANCE POPS
WERE BROUGHT INTO OUR N-CNTRL KS COUNTIES. HAVE FOLLOWED THE 00Z
WRF RUNS FROM THE NAM... THE NSSL WRF AND THE 07Z/08Z 13 KM RAP
WHICH DO NOT REFIRE CONVECTION.
OTHER MESOSCALE DETAILS: WITH THE HIGH DRIFTING FURTHER E...THE
E-W ORIENTED BAND OF RICH 850 MB MOISTURE ALONG THE FRONT WILL
BEGIN CIRCULATING NW...LIFTING INTO NEB. HOWEVER...SURFACE
DEWPOINTS UPSTREAM OVER IA WERE STILL IN THE MID 40S. SO WHILE IN
SITU DEWPOINTS HAVE RISEN OVERNIGHT...VERY LOW-LEVEL DRY AIR
ADVECTION WILL BE OCCURRING.
ISOLATED TSTMS COULD FIRE ALONG THE CONVECTIVELY REINFORCED WARM
FRONT OVER KS. THIS ACTIVITY COULD LIFT INTO OUR N-CNTRL KS
COUNTIES AND THIS IS WHAT IS FCST BY THE NON-HYDROSTATIC MODELS.
NAM PV IMAGES SHOW A SUBTLE SHORTWAVE TROF EMBEDDED IN THE DRY
SLOT CURRENTLY OVER AZ. MOVEMENT IS NNE AND IT IS FCST TO LIFT
ACROSS NM AND INTO CO TONIGHT. THIS SHOULD TRIGGER THE TSTMS LATE
THIS AFTERNOON AND EVENING OVER THE HIGH PLAINS. WE THEN
ANTICIPATE THIS ACTIVITY TO THREATEN OR MOVE INTO THE FCST AREA
FROM THE SW AGAIN TONIGHT. NO GUARANTEES ON THIS THOUGH. SEVERAL
NON-HYDROSTATIC MODELS KEEP THE FCST AREA DRY. SO POPS WERE KEPT
LOW.
TONIGHT: INCREASING CLOUDS WITH A CHANCE OF SHWRS/TSTMS. GREATEST
CHANCE S AND W OF THE TRI-CITIES. EFFECTIVE SHEAR WILL BE AROUND
30 KTS. WHILE AN ISOLATED SEVERE TSTM IS POSSIBLE OVER N-CNTRL KS
BEFORE MIDNIGHT...IT IS LARGELY BASED ON "IF" TSTMS OCCUR AT ALL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 417 AM CDT THU MAY 22 2014
GUIDANCE SUGGESTS A CLOSED UPPER TROPOSPHERIC LOW WILL EXIST OVER
THE SOUTHWESTERN CONUS AT 12Z FRIDAY. THIS CLOSED LOW IS THEN
EXPECTED TO DRIFT TO THE NORTHEAST AND WEAKEN...EVENTUALLY MOVING
OVER THE CENTRAL PLAINS AS AN OPEN WAVE BY EARLY NEXT WEEK. AT THE
SURFACE SOUTH OR SOUTHEASTERLY FLOW IS EXPECTED TO PERSIST ACROSS
THE AREA THROUGH MUCH OF THE LONG TERM FORECAST PERIOD.
UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE SOUTHWESTERN
UPPER TROPOSPHERIC CLOSED LOW...ALONG WITH MULTIPLE SUBTLE UPPER
TROPOSPHERIC PERTURBATIONS EJECTING FROM THE SOUTHWESTERN
CONUS...WILL CONTINUE TO PROMOTE CHANCES FOR PRECIPITATION ACROSS
THE CWA MOST EVERY DAY DURING THE LONG TERM FORECAST PERIOD. WENT
AHEAD AND TOOK AN EVEN BLEND OF NAM...OPERATIONAL GFS...EC...SREF-
MEAN AND WPC GUIDANCE TO DERIVE QPF GRIDS BOTH FRIDAY AND
SATURDAY...AND THEN DERIVED THE POP GRIDS FROM THESE QPF GRIDS.
AFTER ALL WAS SAID AND DONE...VERY LITTLE CHANGE WAS MADE TO THE
GOING FORECAST. OVERALL...30-60% POPS REMAIN INTACT FOR THE MOST
PART ACROSS THE CWA FRIDAY THROUGH SATURDAY NIGHT. SUNDAY AND
BEYOND...ALLBLEND PROVIDED 20-60% POPS TO VARIOUS PORTIONS OF THE
CWA DURING THE LONG TERM FORECAST PERIOD. THESE POPS WERE LEFT
UNCHANGED FOR THE MOST PART.
CONTINUED SOUTH/SOUTHEASTERLY LOWER TROPOSPHERIC FLOW SHOULD KEEP
INCREASED VALUES OF LOWER TROPOSPHERIC MOISTURE INTACT ACROSS THE
AREA THROUGH EARLY TO MID NEXT WEEK...THUS RESULTING IN 1000-
3000J/KG OF POTENTIAL INSTABILITY EACH AFTERNOON AND EVENING.
ALTHOUGH DEEP-LAYER BULK SHEAR WONT BE ANYTHING TO GET EXCITED
ABOUT...THE MAGNITUDE OF POTENTIAL INSTABILITY ALONE COULD BE
ENOUGH TO PROMOTE STRONG UPDRAFT PRODUCTION CAPABLE OF RESPECTABLE
HAIL SIZE AND PERHAPS DOWN-BURST WIND. THE INHERITED HWO ALREADY
HAD A MENTION OF STRONG STORMS EACH AFTERNOON AND EVENING AND AT
THIS TIME THERE REALLY IS NO REASON TO CHANGE THIS. AS A
RESULT...WENT AHEAD AND MENTIONED THE POSSIBILITY OF STRONG
THUNDERSTORMS EACH AFTERNOON AND EVENING FRIDAY THROUGH NEXT
WEDNESDAY.
LITTLE IF ANY CHANGE IN THE LOWER TROPOSPHERIC AIR MASS WILL
PRESENT SIMILAR TEMPERATURE READINGS FROM DAY TO DAY DURING THE
LONG TERM FORECAST PERIOD...WITH HIGHS GENERALLY IN THE 70S AND
80S AND LOWS IN THE 50S AND 60S CURRENTLY FORECAST.
&&
.AVIATION...(FOR THE 06Z GRI TAF THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1232 AM CDT THU MAY 22 2014
REST OF TONIGHT: MULTI-LAYERED VFR CLOUDS WILL INVADE AND DESCEND
WITH MVFR RAIN MOVING IN BY 08Z. CANT RULE OUT SOME THUNDER BUT
WILL AMEND THE TAF TO INCLUDE TSRA IF TRENDS WARRANT. WINDS WILL
REMAIN NE-ENE BELOW 10 KTS. CONFIDENCE: HIGH
THU: RAIN WILL END PRIOR TO DAYBREAK LEAVING VFR CONDITIONS. MOST
OF THE DAY SHOULD BE DRY. NOT SURE EXACTLY WHEN OR IF TSTMS WILL
REDEVELOP AS A FORCING MECHANISM IS LACKING. WINDS WILL SHIFT TO
THE E AROUND 10 KTS. CONFIDENCE: MEDIUM
THU EVE: VFR BUT THERE IS A CHANCE SHWRS/TSTMS COULD MOVE IN.
CONFIDENCE: LOW
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
351 AM CDT THU MAY 22 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT THU MAY 22 2014
A CLOSED UPPER LOW WAS LOCATED IN SRN CALIF/SWRN NV EARLY THIS
MORNING WITH UPSTREAM RIDING FROM THE LOWER MISSISSIPPI VALLEY
NORTHWESTWARD INTO WYOMING. MAIN AREA OF CONVECTION FROM NCTRL
KANSAS INTO CENTRAL NEBRASKA WILL CONTINUE TO MOVE NORTHEAST PRIOR
TO 12Z. THERE APPEAR TO BE A SHORTWAVE MOVING INTO EAST CENTRAL
CO...WHICH IS HELPING TO MAINTAIN AND DEVELOP SHOWERS AND A FEW
THUNDERSTORMS IN NERN CO INTO FAR SOUTHERN NEBR PNHDLE AND FAR SWRN
NEBR. WILL KEEP A 20 TO 30 PERCENT CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS MAINLY WEST OF MERRIMAN THROUGH NORTH PLATTE THIS
MORNING.
OVERALL UPSLOPE FLOW CONTINUES ACROSS THE CENTRAL PLAINS AND INTO
THE FOOTHILLS OF COLORADO AND EASTERN WYOMING TODAY. HIGHS TODAY
FROM 74 TO 80 DEGREES TO BE HINDERED SLIGHTLY BY CONTINUED UPSLOPE
LOW LEVEL WIND FLOW AND PARTLY TO AT TIMES MOSTLY CLOUDY SKIES
TODAY. WILL SEE AN UPTICK IN DEWPOINTS TODAY TO THE MID 50S AIDED BY
SOUTHEASTERLY SFC WINDS. BY LATE AFTERNOON...GREATEST INSTABILITY
AXIS TO RUN FROM CHEYENNE WY THROUGH AKRON CO AND GOODLAND KS.
STRONG TO SEVERE STORMS SHOULD DEVELOP ACROSS THIS AREA THIS
AFTERNOON AND DRIFT SLOWLY NORTHEAST TONIGHT. OTHER SHOWERS AND
THUNDERSTORMS ALSO POSSIBLE OR ONGOING IN WESTERN NEBRASKA THIS
AFTERNOON AND TONIGHT...ALTHOUGH ORGANIZED CLUSTER SHOULD RESIDE
FROM NERN CO INTO NWRN KANSAS AND POSSIBLY INTO SWRN NEBR TONIGHT.
HAVE THE HIGHEST POPS NEAR 50 PERCENT FOR SWRN NEBR AND BRING A
SLIGHT CHC TO NERN AREAS LATE TONIGHT. A FEW STORMS COULD BECOME
SEVERE BY EARLY EVENING SOUTHWEST OF CHAPPELL THROUGH HAYES CENTER.
OTHERWISE LOWS TONIGHT SHOULD RANGE IN THE MID AND UPPER 50S UNDER
MOSTLY CLOUDY SKIES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 318 AM CDT THU MAY 22 2014
AN UPPER LEVEL AREA OF LOW PRESSURE WILL SLOWLY TRACK FROM THE
DESERT SOUTHWEST TO THE MID MISSISSIPPI VALLEY THROUGH THE PERIOD.
THIS WILL BE A VERY SLOW MOVING SYSTEM...WITH ABUNDANT LOW LEVEL
GULF MOISTURE PUSHING NORTHWARD INTO THE CENTRAL AND NORTHERN
PLAINS. PLENTY OF CLOUD COVER CAN BE EXPECTED THROUGH MOST OF THE
MEMORIAL DAY WEEKEND...WITH AREAS OF OVERCAST LOW STRATUS CLOUDS
AND BROKEN TO OCCASIONALLY OVERCAST MID AND HIGH LEVEL CLOUDS.
HIGH TEMPERATURES THROUGH THE WEEKEND WILL BE A CHALLENGE...AND
COULD END UP BEING COOLER IF THE LOWER STRATUS CLOUD DECK DOES NOT
DISSIPATE. THIS SEEMS MOST LIKELY TO OCCUR BOTH FRIDAY AND
SATURDAY...AND HAVE TRENDED THE HIGHS ON BOTH OF THOSE DAYS DOWN A
COUPLE OF DEGREES. IF IT BECOMES OBVIOUS THE STRATUS WILL NOT
CLEAR OR THIN OUT...THEN HIGHS WILL HAVE TO BE LOWERED FURTHER
INTO THE MID AND UPPER 60S ON THOSE TWO DAYS.
PRECIPITATION CHANCES LOOK OKAY BUT NOT GREAT FRIDAY THROUGH
MEMORIAL DAY. THE 28/00Z RUNS OF THE GFS AND ECMWF KEEP THE BEST
DYNAMICS ACROSS THE SOUTHERN PLAINS...AND WITH NO REAL BOUNDARIES
ACROSS THE REGION FOR CONVECTION TO FOCUS ON...WILL BE
CONSERVATIVE WITH THE POP CHANCES. IN FACT WILL TAPER BACK CHANCES
JUST A BIT FROM THE PREVIOUS FORECAST...AS THE ECMWF HAS TRENDED
TOWARD THE FARTHER SOUTH GFS.
WILL KEEP CONDITIONS DRY TUESDAY AND BEYOND...AS THE UPPER LOW
SHOULD BE EAST/SOUTHEAST OF THE REGION BY THEN. LOW LEVEL
MOISTURE WILL BE LEFT IN IT/S WAKE HOWEVER...AND THE NEXT SYSTEM
WILL HAVE PLEANTY OF MOISTURE TO WORK WITH AS IT APPROACHES LATE
IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 132 AM CDT THU MAY 22 2014
FOR THE 06Z KLBF AND KVTN TAFS...THE NEAR TERM CONVECTIVE
ALLOWING MODELS HAVE BACKED OFF ON ADDITIONAL STORMS THURSDAY
MORNING/EARLY AFTERNOON...WHEREAS OUR LATEST NAM12 GUIDANCE
SUGGESTS STORM RE-DEVELOPMENT AS EARLY AS 15Z. ATTM...WILL SIDE
WITH THE NEAR TERM GUIDANCE OF THE RAP13 AND HRRR WHICH HOLDS OFF
STORMS UNTIL AFTER 18Z OR LATER. WITH LOW CONFIDENCE...WILL
INCLUDE A PROB30 AT KLBF FOR 00-04Z...AND KEEP KVTN DRY. UPDATES
MAY BE AND ARE EXPECTED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ROBERG
LONG TERM...TAYLOR
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
133 AM CDT THU MAY 22 2014
.SYNOPSIS...
ISSUED AT 322 PM CDT WED MAY 21 2014
A FAIRLY STAGNANT UPPER LEVEL PATTERN WAS NOTED ACROSS
THE LOWER 48 THIS MORNING. WITH THE EXCEPTION OF FLAGSTAFF AZ...NO
UA SITES HAD HT FALLS OR RISES IN EXCESS OF 50 METERS. THE MAIN
FEATURES OF NOTE ACROSS THE LOWER 48 WERE HIGH PRESSURE OVER THE
MISSISSIPPI DELTA...A STRONG SHORTWAVE OFF THE COAST OF MAINE...AND
A CLOSED LOW OVER NEVADA. A WEAK JET STREAK AROUND 50 KTS WAS NOTED
FROM NRN AZ INTO WESTERN COLORADO. A COUPLE OF WEAK SHORTWAVES WERE
NOTED EARLY THIS AFTERNOON ALONG THE WESTERN SLOPES OF
COLORADO...AND OVER EASTERN NEW MEXICO. THESE TWO DISTURBANCES HAVE
LED TO INCREASED CLOUD COVER OVER WESTERN COLORADO...WYOMING...AS
WELL AS EASTERN NEW MEXICO AND THE TX PANHANDLE. AT THE
SURFACE...HIGH PRESSURE HAS PUSHED INTO THE DAKOTAS AND NORTHERN
NEBRASKA THIS AFTERNOON...FORCING A FRONTAL BOUNDARY INTO THE TEXAS
PANHANDLE. THIS BOUNDARY THEN WINDS TO THE WEST NORTHWEST ALONG THE
FRONT RANGE OF COLORADO AND WYOMING. WITH EASTERLY AND NORTHEASTERLY
WINDS...UNDER CLEAR TO PARTLY CLOUDY SKIES...2 PM CDT TEMPERATURES
RANGED FROM 65 AT AINSWORTH...TO 75 AT IMPERIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 322 PM CDT WED MAY 21 2014
WEAK PV ANOMALY MOVING NWD ALONG THE FRONT RANGE OF CO PER WV
IMAGERY SHOULD CONTINUE TO GENERATE SFC PRESSURE FALLS IN THE LEE OF
THE PALMER DIVIDE AND ENHANCE EXISTING UPSLOPE FLOW TO INITIATE TSRA
ALONG THE HIGHER TERRAIN INITIALLY...WITH ORGANIZED CONVECTIVE
MOVEMENT EXPECTED TO BE NORTHEASTWARD INTO WESTERN AND SW NEB. SHORT
RANGE MODEL FCST SOUNDINGS INDICATE SOME REMAINING...THOUGH
ELEVATED...INSTABILITY OVERNIGHT. HOWEVER MOISTURE IS NOT OVERLY
IMPRESSIVE FURTHER NORTHEAST INTO CENTAL NEBR SINCE NRLY/NERLY FLOW
AT THE SFC ADVECTING ONLY MID TO UPPER 40S DEW POINTS. IN THE
ABSENCE OF A WELL DEFINED LLJ CONVECTION WILL HAVE A DIFFICULT TIME
BEING SUSTAINED INTO CENTRAL NEBR...MUCH LIKE LAST FEW NIGHTS.
HOWEVER...SINCE ORGANIZED CONVECTION WILL LIKELY BE MORE WIDESPREAD
IT MAY HAVE BETTER POTENTIAL. SHORT RANGE MODELS CURRENTLY ARE IN
DISAGREEMENT WITH THIS. HRRR ENSEMBLE UPDRAFT HELICITY SUGGESTS
ORGANIZATION OF INDIVIDUAL UPDRAFTS WOULD WEAKEN AS ANY REMAINING
STORMS MOVE INTO SW NEB. HARD TO ASSESS POTENTIAL FOR SVR...MODELS
SOUNDINGS SHOW SOME CAPE IN THE LOWER RANGE OF THE HAIL GROWTH
REGION...STILL BETTER POPS ARE INCLUDED TONIGHT MOST AREAS THAN PREV
NIGHTS.
WOULD EXPECT A SIMILAR SCENARIO THURSDAY MORNING AS WITH LAST COUPLE
OF MORNINGS IN THAT CONVECTIVE DEBRIS WILL REMAIN ACROSS SOME
PORTIONS OF THE CWA...THOUGH PINPOINTING WHERE IS DIFFICULT.
THEREFORE POPS INCLUDED PRIMARILY WHERE ELEVATED INSTABILITY
RESIDES. UPPER LOW OVER THE SOUTHWEST MOVES LITTLE BUT PIVOTS TO
BECOME SLIGHTLY NEGATIVELY TILTED THURS AFTERNOON. AS A RESULT WINDS
SHOULD BECOME MORE SOUTHEASTERLY AND ADVECT BETTER MOISTURE BACK
INTO THE AREA. FEEL MORE ORGANIZED CONVECTION THURSDAY SHOULD AGAIN
ENTER WESTERN NEB AFTER 00Z FRI. HIGHS WILL BE TEMPERED SOME BY
CLOUD COVER EARLY...BUT SHOULD RECOVER IN THE AFTERNOON MUCH LIKE
TODAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 322 PM CDT WED MAY 21 2014
FOR THURSDAY NIGHT THROUGH SATURDAY...PRECIPITATION CHANCES CONTINUE
TO BE THE MAIN FORECASTING CHALLENGE IN THE MID RANGE PERIODS. LIKE
THIS AFTERNOON...THUNDERSTORMS ARE EXPECTED TO BE ONGOING BY
THURSDAY EVENING OVER NERN COLORADO AND NWRN KS INVOF OF A STALLED
OUT FRONTAL BOUNDARY. WEAK SOUTHERLY AND SSWRLY STEERING WINDS WILL
LIFT THIS ACTIVITY NORTH INTO WESTERN NEBRASKA THURSDAY EVENING. AS
HAS BEEN THE CASE OVER THE PAST COUPLE OF NIGHTS...THIS ACTIVITY HAS
WEAKENED SUBSTANTIALLY AS IT MOVES INTO THE FORECAST AREA FROM THE
WEST AND SOUTHWEST. HOWEVER...TOMORROW NIGHT INTO FRIDAY...LOW LEVEL
WINDS WILL SHIFT MORE TO THE SOUTHEAST AS SURFACE HIGH PRESSURE
LIFTS INTO THE UPPER MISSISSIPPI VALLEY THIS SHIFT IN THE WIND
DIRECTION WILL SERVE TWO PURPOSES...A INCREASE LOW LEVEL
MOISTURE-BRINGING DEW POINTS BACK INTO THE 50S AND B...LEAD TO A 20
TO 30 KT LOW LEVEL JET THURSDAY NIGHT...WHICH WILL HELP TO SUSTAIN
CONVECTION INTO THE LATE NIGHT HOURS. WITH THE FLOW BEING FAIRLY
WEAK IN THE MID LEVELS AND DEEP MID LAYER INSTABILITY BEING FAIRLY
MEAGER...DECIDED TO LEAVE POPS IN THE 30 TO 50 PERCENT RANGE AS
COVERAGE IS EXPECTED TO REMAIN SCATTERED. ON FRIDAY...THE FRONTAL
BOUNDARY WILL LIFT NORTH INTO SOUTHWESTERN AND WESTERN
NEBRASKA...ALLOWING SHOWERS AND THUNDERSTORMS TO LINGER DURING THE
DAYTIME HOURS. CAPPING ON FRIDAY IS WEAK PER THE LATEST NAM AND GFS
SOLNS...SO AFTERNOON HEATING DURING THE DAYTIME HOURS...WILL QUICKLY
LEAD TO ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT. IN
ADDITION...FCST QPF`S ARE EXPECTED TO BE THE HIGHEST FRIDAY/FRIDAY
NIGHT...GIVEN THE EXPECTED WEAK STEERING WINDS AND PWATS OF 1.25 TO
1.50 INCHES. WITH RESPECT TO SEVERE POTENTIAL FRIDAY...AT THIS
TIME...THE SEVERE THREAT FOR FRIDAY APPEARS TO BE MARGINAL GIVEN THE
WEAK MID LEVEL FLOW...ALONG WITH LITTLE OR NO CAP...WHICH WILL
PRODUCE COMPETING UPDRAFTS AND DISORGANIZED CLUSTERS OF STORMS. ON
SATURDAY...THE FRONTAL BOUNDARY WILL LIFT EAST INTO CENTRAL PORTIONS
OF THE FORECAST AREA...FORCED BY THE APPROACH OF THE UPPER LEVEL LOW
AND TROUGH...WHICH WILL REACH THE FOUR CORNERS BY 00Z SUNDAY. THOUGH
PCPN CHANCES REMAIN POSSIBLE ACROSS THE ENTIRE FORECAST AREA...THE
HIGHEST POPS SATURDAY AND SATURDAY NIGHT WILL BE CARRIED ALONG AND
NORTH OF THE FRONT...IMPACTING MAINLY NORTHERN AND EASTERN PORTIONS
OF THE FORECAST AREA.
SUNDAY THROUGH WEDNESDAY...THE UPPER LEVEL LOW WILL BEGIN TO FILL ON
SUNDAY AS IT LIFTS EAST INTO THE SRN PLAINS. PCPN CHANCES WILL
LINGER SUNDAY INTO MONDAY...BEFORE THE SYSTEM EXITS THE SOUTHERN
PLAINS INTO THE ARKLATEX. DRIER AND WARMER CONDITIONS ARE EXPECTED
TUESDAY INTO WEDNESDAY AS A POSITIVELY TILTED RIDGE EXTENDS FROM THE
DESERT SOUTHWEST INTO NRN MINNESOTA. HIGHS WILL RETURN TO THE LOWER
80S FROM THE MIDDLE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 132 AM CDT THU MAY 22 2014
FOR THE 06Z KLBF AND KVTN TAFS...THE NEAR TERM CONVECTIVE
ALLOWING MODELS HAVE BACKED OFF ON ADDITIONAL STORMS THURSDAY
MORNING/EARLY AFTERNOON...WHEREAS OUR LATEST NAM12 GUIDANCE
SUGGESTS STORM RE-DEVELOPMENT AS EARLY AS 15Z. ATTM...WILL SIDE
WITH THE NEAR TERM GUIDANCE OF THE RAP13 AND HRRR WHICH HOLDS OFF
STORMS UNTIL AFTER 18Z OR LATER. WITH LOW CONFIDENCE...WILL
INCLUDE A PROB30 AT KLBF FOR 00-04Z...AND KEEP KVTN DRY. UPDATES
MAY BE AND ARE EXPECTED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
414 AM EDT THU MAY 22 2014
.SYNOPSIS...
AFTER A PLEASANTLY WARM AND DRY WEDNESDAY...AN UPPER-LEVEL
DISTURBANCE OVER THE NORTHERN GREAT LAKES WILL HAVE AN INCREASING
INFLUENCE ON OUR WEATHER AS IT SHIFTS SOUTHEASTWARD ACROSS NEW
YORK AND NEW ENGLAND THURSDAY AND FRIDAY. CLOUDS WILL BE ON THE
INCREASE OVERNIGHT TONIGHT...WITH A CHANCE FOR RAIN SHOWERS
TOWARD MORNING...MAINLY ACROSS NORTHERN NEW YORK AND INTO SOUTH-
CENTRAL VERMONT. SHOWERS WILL BECOME MORE WIDESPREAD ACROSS THE
REGION WITH DAYTIME HEATING ON THURSDAY. LOOK FOR MOSTLY CLOUDY
SKIES WITH NUMEROUS SLOW-MOVING SHOWERS...AND A SLIGHT CHANCE OF
AN AFTERNOON THUNDERSTORM. INTERVALS OF RAIN WILL CONTINUE
THURSDAY NIGHT INTO FRIDAY...WITH THE FOCUS FOR THE MOST
WIDESPREAD ACTIVITY EXPECTED ACROSS NORTHERN NEW YORK. DRIER
WEATHER WILL RETURN FOR THE WEEKEND AS THE UPPER LEVEL LOW SHIFTS
SOUTHEAST OF NEW ENGLAND AND A WEAK RIDGE OF HIGH PRESSURE BUILDS
IN ACROSS THE ST. LAWRENCE VALLEY.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
AS OF 128 AM EDT THURSDAY...MAIN CHANGE FOR THIS LATEST UPDATE IS
TO RAISE MIN TEMPS AS WE ARE STILL 62 DEGREES HERE AT BTV. USED
THE MATCH LAV WHICH LOOKED GOOD. ALSO RAISED POPS A BIT WHERE
THERE ARE ALREADY SHOWERS ACROSS PARTS OF THE DACKS AND NORTHERN
NY. HAVE ADDED MENTION OF SLIGHT CHANCE THUNDER AS WELL WITH
THUNDERSTORM CURRENTLY MOVING INTO EXTREME WESTERN SAINT LAWRENCE
COUNTRY. PREVIOUS DISCUSSIONS FOLLOW.
ADDL SMALL ADJUSTMENTS TO POPS ACROSS THE AREA
OVERNIGHT...CONFINING ANY ISOLD/WIDELY SCT ACTIVITY TO OUR
SOUTHWESTERN COUNTIES AND LEAVING REMAINDER OF FORECAST AREA
GENERALLY DRY OVERNIGHT. CAN`T COMPLETELY RULE OUT ISOLD THUNDER
SOUTHWEST PER LATEST RAP SHOWALTER PROGS...BUT OMITTED MENTION
DUE TO EXPECTED PAUCITY OF COVERAGE. TEMPS/TD/SKY/WINDS REMAIN ON
TRACK SO NO OTHER CHANGES NEEDED AT THIS POINT. HAVE A GREAT
NIGHT. PRIOR DISCUSSIONS FOLLOW...
PRIOR DISCUSSION... A FEW UPDATES AS WE PROGRESS INTO THE EVENING
HOURS...MAINLY TO INTRODUCE A LOW CHANCE OF SHOWERS FOR THE
WESTERN SLOPES OF THE DACKS INTO THE SLV AND TO INCREASE CLOUD
COVER ACROSS THE AREA SOMEWHAT. CURRENT RADAR SHOWING ISOLD TO
WIDELY SCT SHOWERS HAVE DEVELOPED ACROSS PORTIONS OF THE SLV
EARLY THIS EVENING. SOME HEAVIER T-STORM ACTIVITY ALSO EVIDENT
FURTHER WEST ACROSS SOUTHERN ONTARIO INVOF PEMBROKE/RENFREW WHERE
LOCAL WARNINGS ARE IN EFFECT FROM ENV CANADA. NOT EXPECTING ANY
STORM ACTIVITY TO REACH OUR NRN NY COUNTIES THIS EVENING AS
AIRMASS REMAINS QUITE STABLE OVER OUR AREA. HOWEVER...A MID LEVEL
SHEAR ZONE HAS MATERIALIZED ACROSS THESE AREAS PER LATEST RAP
PROGS...AND WITH AT LEAST SOME SUPPORT FROM ~90KT UPPER LEVEL JET
TO THE IMMEDIATE SOUTHWEST...I LIKE THE MOST RECENT RAP/HRRR
PROGS SHOWING CONTINUED SCT SHOWER ACTIVITY IN THESE AREAS
OVERNIGHT AS MID LEVEL HEIGHTS SLOWLY FALL. MORE LIMITED ACTIVITY
NORTH AND EAST OF A KMSS-KBTV-KVSF LINE UNTIL LATER TONIGHT AS
THESE AREAS INITIALLY FURTHER REMOVED FROM BETTER MOISTURE/UPPER
LEVEL SUPPORT. DID OPT TO BLEND POPS FROM 06Z ONWARD INTO CURRENT
FORECAST AT 12Z...BUT IF CURRENT TRENDS CONTINUE MAY HAVE TO
ADJUST POPS FURTHER DOWNWARD NORTH AND EAST LATER TONIGHT. REST
OF FORECAST IN GOOD SHAPE AT THIS POINT.
PRIOR DISCUSSION... NARROW SFC RIDGE CENTERED ACROSS THE NORTH
COUNTRY RESULTING IN A PLEASANT AFTN WITH JUST SCATTERED FAIR
WEATHER CUMULUS CLOUDS DOTTING THE HIGHER TERRAIN PER AFTN
VISIBLE IMAGERY. 2-M TEMPS REACHED THE MID 70S (77F AT KBTV AT
1830Z) AS EXPECTED AREAWIDE...WITH DELIGHTFULLY LOW DEWPOINTS IN
THE 30S TO LOWER 40S. WINDS HAVE ALSO BEEN RATHER LIGHT IN VCNTY
OF PREVAILING SFC ANTICYCLONE. PLEASANT CONDITIONS WILL CONTINUE
THROUGH THIS EVENING WITH TEMPERATURES FALLING THROUGH THE 60S
WITH ONSET OF DIURNAL COOLING CYCLE.
SOME GRADUAL CHANGES WILL OCCUR LATE TONIGHT. THE 850MB FRONTAL
ZONE ACROSS SRN MI/NRN OH/PA...WHICH HAS BEEN THE FOCUS FOR
SHOWER AND TSTM ACTIVITY OVER THE PAST 12-24 HRS...WILL SLOWLY
LIFT NEWD...BUT IS ALSO EXPECTED TO SLOWLY WEAKEN. AT THE SAME
TIME ...MID-LEVEL HEIGHT FALLS ARE EXPECTED ACROSS NY/VT AS
CLOSED UPR LOW OVER THE NRN GREAT LAKES BEGINS TO SHIFT INTO SERN
ONTARIO OVERNIGHT. IT SHOULD REMAIN DRY THRU MIDNIGHT ALL
SECTIONS...BUT RESULT OF THE FRONTAL ZONE AND HEIGHT FALLS
SUGGESTS WE SHOULD BEGIN TO SEE SOME ISOLD/SCT SHOWER ACTIVITY
DEVELOP ACROSS OUR NRN NY COUNTIES SEWD INTO RUTLAND COUNTY AFTER
MIDNIGHT...AND ESPECIALLY AFTER 09Z. AIR MASS WILL REMAIN QUITE
DRY FURTHER NORTH AND EAST...SO ACTIVITY SHOULD REMAIN SOUTH AND
WEST OF THE CHAMPLAIN VALLEY THRU DAYBREAK BASED ON CURRENT
INDICATIONS. LOOK FOR A GRADUALLY INCREASE IN MID AND UPPER
LEVELS CLOUDS FROM THE CHAMPLAIN VALLEY NORTH AND EASTWARD LATE.
STAYED CLOSE TO MOS CONSENSUS FOR OVERNIGHT LOWS. WITH INCREASE
IN CLOUDS LATE...WILL SEE TEMPS A BIT WARMER THAN THE PREVIOUS
COUPLE OF NIGHTS. LOWS GENERALLY IN THE UPR 40S TO LOWER
50S...EXCEPT MID 40S FOR THE NORMALLY COOLER VALLEYS WITHIN THE
NRN ADIRONDACK REGION AND ACROSS FAR NERN VT. A LIGHT S-SE WIND
WILL DEVELOP OVERNIGHT AS SFC RIDGE SLIDES EWD INTO MAINE.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH SATURDAY/...
AS OF 253 PM EDT WEDNESDAY...UNSETTLED WX CONDITIONS EXPECTED
THRU MUCH OF THE PERIOD. LOW-MID LEVEL LOW PRESSURE SYSTEM
ROTATES SEWD FROM SERN ONTARIO INTO THE ST. LAWRENCE VALLEY LATE
THURSDAY AFTN...AND THEN SLIDES SLOWLY SEWD ACROSS CENTRAL NEW
YORK STATE (JUST SOUTH OF THE ADIRONDACKS) AND SRN NEW ENGLAND
THURSDAY NIGHT THROUGH FRIDAY. MODELS CONTINUE TO INDICATE BEST
FOCUS FOR WIDESPREAD RAIN SHOWERS WILL BE ALONG AND JUST NORTH OF
THE 700-500MB VORT TRACK...WHICH LINES UP ACROSS OUR NRN
ADIRONDACK ZONES AND INTO S-CENTRAL VT. WITH WEAK INSTABILITY
DEVELOPING WITH COLD POOL ALOFT...FULLY EXPECT ACTIVITY TO BE
MORE WIDESPREAD DURING BOTH THURSDAY AND FRIDAY AFTN...WITH
ACTIVITY A BIT MORE CONCENTRATED NEAR THE UPR LOW DURING THE
OVERNIGHT PERIOD THURSDAY NIGHT. COULD BE COLD ENOUGH (WBZ
HEIGHTS 6-7 KFT) TO RESULT IN SOME PEA-SIZED HAIL WITH STRONGER
CORES BOTH THURSDAY AND FRIDAY AFTERNOONS. HAVE LEFT OUT SPECIFIC
MENTION OF THAT FOR NOW GIVEN WEAK INSTABILITY (<500 J/KG)...BUT
HAVE INCLUDED A SLIGHT CHANCE OF TSTMS FROM THE GREEN MTNS WWD ON
THURSDAY AFTN...AND AREAWIDE FRIDAY AFTN.
COVERAGE OF SHOWERS SHOULD DIMINISH NW-SE FRIDAY NIGHT AS UPR LOW
BEGINS TO DEPART SOUTHEAST OF NEW ENGLAND. WILL SHOW DRYING
CONDITIONS AND PARTIAL CLEARING IN THE FORECAST GRIDS FOR FRIDAY
NIGHT.
HYDROLOGICALLY...NEED TO BEWARE OF ANY POTENTIAL SURPRISE UNDER
THE UPPER LOW...BUT AT THIS POINT IT APPEARS HIGHEST RAINFALL
AMTS OF 1.0-1.5" WILL BE FOCUSED ACROSS NRN NY...AND NOT ENOUGH
TO RESULT IN FLOODING. GIVEN SATURATED CONDITIONS...THE BASIN TO
WATCH MOST CLOSELY WILL BE THE AUSABLE...WHICH ROSE TO NEAR 9
FEET (ASFN6) EARLY SUNDAY WITH THE LAST HVY RAIN PRODUCING
SYSTEM. THE RAINFALL WILL ALSO BE STRETCHED OUT ACROSS A 36-48
HOUR PERIOD. IN COMBINATION WITH ACTIVELY GROWING VEGETATION THIS
TIME OF YEAR...RUNOFF SHOULDN`T BE A SIGNIFICANT CONCERN GIVEN
CURRENT QPF EXPECTATIONS.
REMAINED CLOSE TO MOS CONSENSUS FOR DAYTIME HIGHS...GENERALLY UPR
60S TO LOWER 70S ON THURSDAY...AND MID-UPR 60S FRIDAY WITH COLD
POOL ALOFT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 412 AM EDT THURSDAY... OUR REGION IS UNDER A NORTHWEST FLOW
ALOFT THROUGH THE PERIOD LEAVING US BETWEEN A COOL CANADIAN
AIRMASS TO OUR EAST AND A WARM CONTINENTAL AIRMASS TO THE WEST.
THERE WILL BE SEVERAL DISTURBANCES IN THE FLOW ESPECIALLY SUNDAY
THROUGH TUESDAY BUT TEMPERATURES WILL BE AT OR SLIGHTY ABOVE
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE 70S AND LOWS IN THE
40S AND 50S.
MODELS ARE NOT IN GOOD AGREEMENT WITH THE DAILY FEATURES LEADING
TO BELOW AVERAGE CONFIDENCE IN THE WEATHER THIS PERIOD.
ONE SHORT WAVE TROUGH ALOFT WILL SLIDE SEWD ON SUNDAY WITH A WEAK
WARM FRONT DEVELOPING AT THE SURFACE...KEEPING A CHANCE OF
SHOWERS MAINLY FROM THE ADIRONDACKS ACROSS VT ON SUNDAY.
THIS IS WHERE THE MODEL DIVERGENCE STARTS GROWING WITH THE STRENGTH
OF THE UPPER LEVEL TROF. MODEL DIFFERENCES GROW FURTHER MONDAY
WITH WHICH AIRMASS WE WILL BE INFLUENCED BY MOST. HAVE LEANED
TOWARD A WARMER AND DRIER ECMWF SOLUTION WITH HIGHS WELL INTO THE
70S, BUT IT COULD EVEN BE WARMER IN THE LOWER 80S WITH 850 TEMPS AS
HIGH AS +12C CONTRASTED TO A COOLER +7 ON THE GFS WHICH WOULD
YIELD TEMPS CLOSER TO 70.
MONDAY NIGHT AND TUESDAY LOW PRESSURE AND ASSOCIATED COLD FRONT WILL
BRING ANOTHER CHANCE FOR SHOWERS, PERHAPS A THUNDERSTORM.
BY WEDNESDAY DESPITE DIFFERENCE IN UPPER LEVEL SOLUTIONS, IT
LOOKS LIKE NORMAL TEMPS AND VERY DRY AIRMASS FROM CANADA WILL MOVE
INTO THE AREA.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
THROUGH 06Z FRIDAY...EXPECTING MAINLY VFR CONDITIONS WITH
INCREASING COVERAGE OF SHOWERS THROUGH 00Z FRI AS SURFACE LOW
PRESSURE WILL BE NEARLY STATIONARY OVER NORTHERN NY WITH SE FLOW
OVER VT. AFT 00Z FRI...CIGS LOWERING TO MVFR WITH LIGHT WINDS AND
HIGH RELATIVE HUMIDITY LEADING TO BR LATE IN THE PERIOD AS SHOWERS
WIND DOWN.
ISOLATED SHOWERS AND A THUNDERSTORMS GOING EARLY THIS MORNING
MAINLY IN NY. COVERAGE IS SO LIMITED THAT WILL ONLY SHOW WITH VCSH
FOR NOW EXCEPT AT KSLK WHERE -SHRA PREVAIL.
SHOWERS AND POSSIBLE THUNDERSTORM DEVELOPMENT IS EXPECTED AFTER
13Z THURSDAY AT ALL TAF SITES WITH COVERAGE MORE WIDESPREAD BY
16-18Z WITH WEAK INSTABILITY. DID NOT INCLUDE THUNDER IN THE TAFS
AT THIS POINT AS PROBABILITY AT ANY POINT IS LOW.
CEILINGS/VISIBILITIES WILL BE PRIMARILY VFR...HOWEVER SOME
PERIODS OF REDUCTIONS TO MVFR OR EVEN IFR ARE POSSIBLE IN ANY
HEAVIER OR MORE ORGANIZED SHOWER ACTIVITY.
SOUTH/SOUTHEAST AT 5-10 KNOTS EXCEPT MSS WHERE NORTHEAST WINDS ARE
EXPECTED THROUGH THE PERIOD.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
06Z FRI THRU 12Z FRI...MVFR CIGS...LOCALLY IFR AT KMPV/KSLK IN STRATUS
AND FOG.
12Z FRI THRU 00Z SAT...IFR/MVFR EARLY BECOMING VFR/MVFR WITH SCATTERED
SHOWERS/THUNDERSTORMS.
00Z SAT THRU 00Z MON...MAINLY VFR WITH SCATTERED MVFR SHOWERS
SATURDAY AFTERNOON...AND ISOLATED SHOWERS SUNDAY AFTERNOON.
00Z MON ONWARD...GENERALLY DRY WITH VFR CONDITIONS UNDER SFC HIGH
PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/JMG/NEILES
SHORT TERM...BANACOS
LONG TERM...SISSON
AVIATION...SISSON
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
152 AM EDT THU MAY 22 2014
.SYNOPSIS...
AFTER A PLEASANTLY WARM AND DRY WEDNESDAY...AN UPPER-LEVEL
DISTURBANCE OVER THE NORTHERN GREAT LAKES WILL HAVE AN INCREASING
INFLUENCE ON OUR WEATHER AS IT SHIFTS SOUTHEASTWARD ACROSS NEW
YORK AND NEW ENGLAND THURSDAY AND FRIDAY. CLOUDS WILL BE ON THE
INCREASE OVERNIGHT TONIGHT...WITH A CHANCE FOR RAIN SHOWERS
TOWARD MORNING...MAINLY ACROSS NORTHERN NEW YORK AND INTO SOUTH-
CENTRAL VERMONT. SHOWERS WILL BECOME MORE WIDESPREAD ACROSS THE
REGION WITH DAYTIME HEATING ON THURSDAY. LOOK FOR MOSTLY CLOUDY
SKIES WITH NUMEROUS SLOW-MOVING SHOWERS...AND A SLIGHT CHANCE OF
AN AFTERNOON THUNDERSTORM. INTERVALS OF RAIN WILL CONTINUE
THURSDAY NIGHT INTO FRIDAY...WITH THE FOCUS FOR THE MOST
WIDESPREAD ACTIVITY EXPECTED ACROSS NORTHERN NEW YORK. DRIER
WEATHER WILL RETURN FOR THE WEEKEND AS THE UPPER LEVEL LOW SHIFTS
SOUTHEAST OF NEW ENGLAND AND A WEAK RIDGE OF HIGH PRESSURE BUILDS
IN ACROSS THE ST. LAWRENCE VALLEY.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
AS OF 128 AM EDT THURSDAY...MAIN CHANGE FOR THIS LATEST UPDATE IS
TO RAISE MIN TEMPS AS WE ARE STILL 62 DEGREES HERE AT BTV. USED
THE MATCH LAV WHICH LOOKED GOOD. ALSO RAISED POPS A BIT WHERE
THERE ARE ALREADY SHOWERS ACROSS PARTS OF THE DACKS AND NORTHERN
NY. HAVE ADDED MENTION OF SLIGHT CHANCE THUNDER AS WELL WITH
THUNDERSTORM CURRENTLY MOVING INTO EXTREME WESTERN SAINT LAWRENCE
COUNTRY. PREVIOUS DISCUSSIONS FOLLOW.
ADDL SMALL ADJUSTMENTS TO POPS ACROSS THE AREA
OVERNIGHT...CONFINING ANY ISOLD/WIDELY SCT ACTIVITY TO OUR
SOUTHWESTERN COUNTIES AND LEAVING REMAINDER OF FORECAST AREA
GENERALLY DRY OVERNIGHT. CAN`T COMPLETELY RULE OUT ISOLD THUNDER
SOUTHWEST PER LATEST RAP SHOWALTER PROGS...BUT OMITTED MENTION
DUE TO EXPECTED PAUCITY OF COVERAGE. TEMPS/TD/SKY/WINDS REMAIN ON
TRACK SO NO OTHER CHANGES NEEDED AT THIS POINT. HAVE A GREAT
NIGHT. PRIOR DISCUSSIONS FOLLOW...
PRIOR DISCUSSION... A FEW UPDATES AS WE PROGRESS INTO THE EVENING
HOURS...MAINLY TO INTRODUCE A LOW CHANCE OF SHOWERS FOR THE
WESTERN SLOPES OF THE DACKS INTO THE SLV AND TO INCREASE CLOUD
COVER ACROSS THE AREA SOMEWHAT. CURRENT RADAR SHOWING ISOLD TO
WIDELY SCT SHOWERS HAVE DEVELOPED ACROSS PORTIONS OF THE SLV
EARLY THIS EVENING. SOME HEAVIER T-STORM ACTIVITY ALSO EVIDENT
FURTHER WEST ACROSS SOUTHERN ONTARIO INVOF PEMBROKE/RENFREW WHERE
LOCAL WARNINGS ARE IN EFFECT FROM ENV CANADA. NOT EXPECTING ANY
STORM ACTIVITY TO REACH OUR NRN NY COUNTIES THIS EVENING AS
AIRMASS REMAINS QUITE STABLE OVER OUR AREA. HOWEVER...A MID LEVEL
SHEAR ZONE HAS MATERIALIZED ACROSS THESE AREAS PER LATEST RAP
PROGS...AND WITH AT LEAST SOME SUPPORT FROM ~90KT UPPER LEVEL JET
TO THE IMMEDIATE SOUTHWEST...I LIKE THE MOST RECENT RAP/HRRR
PROGS SHOWING CONTINUED SCT SHOWER ACTIVITY IN THESE AREAS
OVERNIGHT AS MID LEVEL HEIGHTS SLOWLY FALL. MORE LIMITED ACTIVITY
NORTH AND EAST OF A KMSS-KBTV-KVSF LINE UNTIL LATER TONIGHT AS
THESE AREAS INITIALLY FURTHER REMOVED FROM BETTER MOISTURE/UPPER
LEVEL SUPPORT. DID OPT TO BLEND POPS FROM 06Z ONWARD INTO CURRENT
FORECAST AT 12Z...BUT IF CURRENT TRENDS CONTINUE MAY HAVE TO
ADJUST POPS FURTHER DOWNWARD NORTH AND EAST LATER TONIGHT. REST
OF FORECAST IN GOOD SHAPE AT THIS POINT.
PRIOR DISCUSSION... NARROW SFC RIDGE CENTERED ACROSS THE NORTH
COUNTRY RESULTING IN A PLEASANT AFTN WITH JUST SCATTERED FAIR
WEATHER CUMULUS CLOUDS DOTTING THE HIGHER TERRAIN PER AFTN
VISIBLE IMAGERY. 2-M TEMPS REACHED THE MID 70S (77F AT KBTV AT
1830Z) AS EXPECTED AREAWIDE...WITH DELIGHTFULLY LOW DEWPOINTS IN
THE 30S TO LOWER 40S. WINDS HAVE ALSO BEEN RATHER LIGHT IN VCNTY
OF PREVAILING SFC ANTICYCLONE. PLEASANT CONDITIONS WILL CONTINUE
THROUGH THIS EVENING WITH TEMPERATURES FALLING THROUGH THE 60S
WITH ONSET OF DIURNAL COOLING CYCLE.
SOME GRADUAL CHANGES WILL OCCUR LATE TONIGHT. THE 850MB FRONTAL
ZONE ACROSS SRN MI/NRN OH/PA...WHICH HAS BEEN THE FOCUS FOR
SHOWER AND TSTM ACTIVITY OVER THE PAST 12-24 HRS...WILL SLOWLY
LIFT NEWD...BUT IS ALSO EXPECTED TO SLOWLY WEAKEN. AT THE SAME
TIME ...MID-LEVEL HEIGHT FALLS ARE EXPECTED ACROSS NY/VT AS
CLOSED UPR LOW OVER THE NRN GREAT LAKES BEGINS TO SHIFT INTO SERN
ONTARIO OVERNIGHT. IT SHOULD REMAIN DRY THRU MIDNIGHT ALL
SECTIONS...BUT RESULT OF THE FRONTAL ZONE AND HEIGHT FALLS
SUGGESTS WE SHOULD BEGIN TO SEE SOME ISOLD/SCT SHOWER ACTIVITY
DEVELOP ACROSS OUR NRN NY COUNTIES SEWD INTO RUTLAND COUNTY AFTER
MIDNIGHT...AND ESPECIALLY AFTER 09Z. AIR MASS WILL REMAIN QUITE
DRY FURTHER NORTH AND EAST...SO ACTIVITY SHOULD REMAIN SOUTH AND
WEST OF THE CHAMPLAIN VALLEY THRU DAYBREAK BASED ON CURRENT
INDICATIONS. LOOK FOR A GRADUALLY INCREASE IN MID AND UPPER
LEVELS CLOUDS FROM THE CHAMPLAIN VALLEY NORTH AND EASTWARD LATE.
STAYED CLOSE TO MOS CONSENSUS FOR OVERNIGHT LOWS. WITH INCREASE
IN CLOUDS LATE...WILL SEE TEMPS A BIT WARMER THAN THE PREVIOUS
COUPLE OF NIGHTS. LOWS GENERALLY IN THE UPR 40S TO LOWER
50S...EXCEPT MID 40S FOR THE NORMALLY COOLER VALLEYS WITHIN THE
NRN ADIRONDACK REGION AND ACROSS FAR NERN VT. A LIGHT S-SE WIND
WILL DEVELOP OVERNIGHT AS SFC RIDGE SLIDES EWD INTO MAINE.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 253 PM EDT WEDNESDAY...UNSETTLED WX CONDITIONS EXPECTED
THRU MUCH OF THE PERIOD. LOW-MID LEVEL LOW PRESSURE SYSTEM
ROTATES SEWD FROM SERN ONTARIO INTO THE ST. LAWRENCE VALLEY LATE
THURSDAY AFTN...AND THEN SLIDES SLOWLY SEWD ACROSS CENTRAL NEW
YORK STATE (JUST SOUTH OF THE ADIRONDACKS) AND SRN NEW ENGLAND
THURSDAY NIGHT THROUGH FRIDAY. MODELS CONTINUE TO INDICATE BEST
FOCUS FOR WIDESPREAD RAIN SHOWERS WILL BE ALONG AND JUST NORTH OF
THE 700-500MB VORT TRACK...WHICH LINES UP ACROSS OUR NRN
ADIRONDACK ZONES AND INTO S-CENTRAL VT. WITH WEAK INSTABILITY
DEVELOPING WITH COLD POOL ALOFT...FULLY EXPECT ACTIVITY TO BE
MORE WIDESPREAD DURING BOTH THURSDAY AND FRIDAY AFTN...WITH
ACTIVITY A BIT MORE CONCENTRATED NEAR THE UPR LOW DURING THE
OVERNIGHT PERIOD THURSDAY NIGHT. COULD BE COLD ENOUGH (WBZ
HEIGHTS 6-7 KFT) TO RESULT IN SOME PEA-SIZED HAIL WITH STRONGER
CORES BOTH THURSDAY AND FRIDAY AFTERNOONS. HAVE LEFT OUT SPECIFIC
MENTION OF THAT FOR NOW GIVEN WEAK INSTABILITY (<500 J/KG)...BUT
HAVE INCLUDED A SLIGHT CHANCE OF TSTMS FROM THE GREEN MTNS WWD ON
THURSDAY AFTN...AND AREAWIDE FRIDAY AFTN.
COVERAGE OF SHOWERS SHOULD DIMINISH NW-SE FRIDAY NIGHT AS UPR LOW
BEGINS TO DEPART SOUTHEAST OF NEW ENGLAND. WILL SHOW DRYING
CONDITIONS AND PARTIAL CLEARING IN THE FORECAST GRIDS FOR FRIDAY
NIGHT.
HYDROLOGICALLY...NEED TO BEWARE OF ANY POTENTIAL SURPRISE UNDER
THE UPPER LOW...BUT AT THIS POINT IT APPEARS HIGHEST RAINFALL
AMTS OF 1.0-1.5" WILL BE FOCUSED ACROSS NRN NY...AND NOT ENOUGH
TO RESULT IN FLOODING. GIVEN SATURATED CONDITIONS...THE BASIN TO
WATCH MOST CLOSELY WILL BE THE AUSABLE...WHICH ROSE TO NEAR 9
FEET (ASFN6) EARLY SUNDAY WITH THE LAST HVY RAIN PRODUCING
SYSTEM. THE RAINFALL WILL ALSO BE STRETCHED OUT ACROSS A 36-48
HOUR PERIOD. IN COMBINATION WITH ACTIVELY GROWING VEGETATION THIS
TIME OF YEAR...RUNOFF SHOULDN`T BE A SIGNIFICANT CONCERN GIVEN
CURRENT QPF EXPECTATIONS.
REMAINED CLOSE TO MOS CONSENSUS FOR DAYTIME HIGHS...GENERALLY UPR
60S TO LOWER 70S ON THURSDAY...AND MID-UPR 60S FRIDAY WITH COLD
POOL ALOFT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM EDT WEDNESDAY...AS SFC HIGH PRESSURE BUILDS OVER THE
CENTRAL GREAT LAKES REGION ON SATURDAY...AN UPPER LVL RIPPLE OF
ENERGY ALONG WITH SOME INSTABILITY WILL ALLOW FOR SCT RAIN
SHOWERS WITH PSBL TS OVER THE NORTH COUNTRY. THE SFC RIDGE WILL
SLIDE SEWD ON SUNDAY...WITH RIDING ALOFT GRADUALLY MOVING
EWD...PUTTING THE NORTH COUNTRY ON THE PERIPHERY OF HIGH
PRESSURE. THIS WILL CAUSE A DRYING TREND...BUT UPPER LVL
DISTURBANCE TRIES TO AFFECT THE AREA...SO CANNOT COMPLETELY RULE
OUT ISOLD-SCT SHOWERS OVER VT ON SUNDAY.
AS THE SFC RIDGE SLIDES INTO THE ATLANTIC OFF THE SERN USA...WE
WILL SEE A BRIEF DRY PERIOD SUNDAY NGT THROUGH MONDAY. SUNDAY
NGT...WEAKENING RIDGING ALOFT AND LOW PRESSURE SYSTEM AT THE SFC
WILL BRING ANOTHER CHANCE FOR SHOWERS...ESP ON TUESDAY.
THIS ACTIVE PATTERN WILL SEE TEMPS ABOVE NORMAL WITH GENERAL
WARMING TREND. SATURDAY...BEING THE COOLEST DAY WILL HAVE MAX
TEMPS IN THE 50S ACROSS THE MTNS AND 60S-AROUND 70 IN THE
VALLEYS. WARMEST DAY LOOKS TO BE MONDAY WITH MTNS IN THE 60S AND
VALLEYS IN THE L70S-L80S. TUESDAY AND WEDNESDAY CONTINUE TO BE
MILD. AT NIGHT...MIN TEMPS WILL RANGE FROM 40S-L50S IN THE MTNS
AND 50S IN THE VALLEYS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THROUGH 06Z FRIDAY...EXPECTING MAINLY VFR CONDITIONS WITH
INCREASING COVERAGE OF SHOWERS THROUGH 00Z FRI AS SURFACE LOW
PRESSURE WILL BE NEARLY STATIONARY OVER NORTHERN NY WITH SE FLOW
OVER VT. AFT 00Z FRI...CIGS LOWERING TO MVFR WITH LIGHT WINDS AND
HIGH RELATIVE HUMIDITY LEADING TO BR LATE IN THE PERIOD AS SHOWERS
WIND DOWN.
ISOLATED SHOWERS AND A THUNDERSTORMS GOING EARLY THIS MORNING
MAINLY IN NY. COVERAGE IS SO LIMITED THAT WILL ONLY SHOW WITH VCSH
FOR NOW EXCEPT AT KSLK WHERE -SHRA PREVAIL.
SHOWERS AND POSSIBLE THUNDERSTORM DEVELOPMENT IS EXPECTED AFTER
13Z THURSDAY AT ALL TAF SITES WITH COVERAGE MORE WIDESPREAD BY
16-18Z WITH WEAK INSTABILITY. DID NOT INCLUDE THUNDER IN THE TAFS
AT THIS POINT AS PROBABILITY AT ANY POINT IS LOW.
CEILINGS/VISIBILITIES WILL BE PRIMARILY VFR...HOWEVER SOME
PERIODS OF REDUCTIONS TO MVFR OR EVEN IFR ARE POSSIBLE IN ANY
HEAVIER OR MORE ORGANIZED SHOWER ACTIVITY.
SOUTH/SOUTHEAST AT 5-10 KNOTS EXCEPT MSS WHERE NORTHEAST WINDS ARE
EXPECTED THROUGH THE PERIOD.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
06Z FRI THRU 12Z FRI...MVFR CIGS...LOCALLY IFR AT KMPV/KSLK IN STRATUS
AND FOG.
12Z FRI THRU 00Z SAT...IFR/MVFR EARLY BECOMING VFR/MVFR WITH SCATTERED
SHOWERS/THUNDERSTORMS.
00Z SAT THRU 00Z MON...MAINLY VFR WITH SCATTERED MVFR SHOWERS
SATURDAY AFTERNOON...AND ISOLATED SHOWERS SUNDAY AFTERNOON.
00Z MON ONWARD...GENERALLY DRY WITH VFR CONDITIONS UNDER SFC HIGH
PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/JMG/NEILES
SHORT TERM...BANACOS
LONG TERM...KGM
AVIATION...SISSON
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
134 AM EDT THU MAY 22 2014
.SYNOPSIS...
AFTER A PLEASANTLY WARM AND DRY WEDNESDAY...AN UPPER-LEVEL
DISTURBANCE OVER THE NORTHERN GREAT LAKES WILL HAVE AN INCREASING
INFLUENCE ON OUR WEATHER AS IT SHIFTS SOUTHEASTWARD ACROSS NEW
YORK AND NEW ENGLAND THURSDAY AND FRIDAY. CLOUDS WILL BE ON THE
INCREASE OVERNIGHT TONIGHT...WITH A CHANCE FOR RAIN SHOWERS
TOWARD MORNING...MAINLY ACROSS NORTHERN NEW YORK AND INTO SOUTH-
CENTRAL VERMONT. SHOWERS WILL BECOME MORE WIDESPREAD ACROSS THE
REGION WITH DAYTIME HEATING ON THURSDAY. LOOK FOR MOSTLY CLOUDY
SKIES WITH NUMEROUS SLOW-MOVING SHOWERS...AND A SLIGHT CHANCE OF
AN AFTERNOON THUNDERSTORM. INTERVALS OF RAIN WILL CONTINUE
THURSDAY NIGHT INTO FRIDAY...WITH THE FOCUS FOR THE MOST
WIDESPREAD ACTIVITY EXPECTED ACROSS NORTHERN NEW YORK. DRIER
WEATHER WILL RETURN FOR THE WEEKEND AS THE UPPER LEVEL LOW SHIFTS
SOUTHEAST OF NEW ENGLAND AND A WEAK RIDGE OF HIGH PRESSURE BUILDS
IN ACROSS THE ST. LAWRENCE VALLEY.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
AS OF 128 AM EDT THURSDAY...MAIN CHANGE FOR THIS LATEST UPDATE IS
TO RAISE MIN TEMPS AS WE ARE STILL 62 DEGREES HERE AT BTV. USED
THE MATCH LAV WHICH LOOKED GOOD. ALSO RAISED POPS A BIT WHERE
THERE ARE ALREADY SHOWERS ACROSS PARTS OF THE DACKS AND NORTHERN
NY. HAVE ADDED MENTION OF SLIGHT CHANCE THUNDER AS WELL WITH
THUNDERSTORM CURRENTLY MOVING INTO EXTREME WESTERN SAINT LAWRENCE
COUNTRY. PREVIOUS DISCUSSIONS FOLLOW.
ADDL SMALL ADJUSTMENTS TO POPS ACROSS THE AREA
OVERNIGHT...CONFINING ANY ISOLD/WIDELY SCT ACTIVITY TO OUR
SOUTHWESTERN COUNTIES AND LEAVING REMAINDER OF FORECAST AREA
GENERALLY DRY OVERNIGHT. CAN`T COMPLETELY RULE OUT ISOLD THUNDER
SOUTHWEST PER LATEST RAP SHOWALTER PROGS...BUT OMITTED MENTION
DUE TO EXPECTED PAUCITY OF COVERAGE. TEMPS/TD/SKY/WINDS REMAIN ON
TRACK SO NO OTHER CHANGES NEEDED AT THIS POINT. HAVE A GREAT
NIGHT. PRIOR DISCUSSIONS FOLLOW...
PRIOR DISCUSSION... A FEW UPDATES AS WE PROGRESS INTO THE EVENING
HOURS...MAINLY TO INTRODUCE A LOW CHANCE OF SHOWERS FOR THE
WESTERN SLOPES OF THE DACKS INTO THE SLV AND TO INCREASE CLOUD
COVER ACROSS THE AREA SOMEWHAT. CURRENT RADAR SHOWING ISOLD TO
WIDELY SCT SHOWERS HAVE DEVELOPED ACROSS PORTIONS OF THE SLV
EARLY THIS EVENING. SOME HEAVIER T-STORM ACTIVITY ALSO EVIDENT
FURTHER WEST ACROSS SOUTHERN ONTARIO INVOF PEMBROKE/RENFREW WHERE
LOCAL WARNINGS ARE IN EFFECT FROM ENV CANADA. NOT EXPECTING ANY
STORM ACTIVITY TO REACH OUR NRN NY COUNTIES THIS EVENING AS
AIRMASS REMAINS QUITE STABLE OVER OUR AREA. HOWEVER...A MID LEVEL
SHEAR ZONE HAS MATERIALIZED ACROSS THESE AREAS PER LATEST RAP
PROGS...AND WITH AT LEAST SOME SUPPORT FROM ~90KT UPPER LEVEL JET
TO THE IMMEDIATE SOUTHWEST...I LIKE THE MOST RECENT RAP/HRRR
PROGS SHOWING CONTINUED SCT SHOWER ACTIVITY IN THESE AREAS
OVERNIGHT AS MID LEVEL HEIGHTS SLOWLY FALL. MORE LIMITED ACTIVITY
NORTH AND EAST OF A KMSS-KBTV-KVSF LINE UNTIL LATER TONIGHT AS
THESE AREAS INITIALLY FURTHER REMOVED FROM BETTER MOISTURE/UPPER
LEVEL SUPPORT. DID OPT TO BLEND POPS FROM 06Z ONWARD INTO CURRENT
FORECAST AT 12Z...BUT IF CURRENT TRENDS CONTINUE MAY HAVE TO
ADJUST POPS FURTHER DOWNWARD NORTH AND EAST LATER TONIGHT. REST
OF FORECAST IN GOOD SHAPE AT THIS POINT.
PRIOR DISCUSSION... NARROW SFC RIDGE CENTERED ACROSS THE NORTH
COUNTRY RESULTING IN A PLEASANT AFTN WITH JUST SCATTERED FAIR
WEATHER CUMULUS CLOUDS DOTTING THE HIGHER TERRAIN PER AFTN
VISIBLE IMAGERY. 2-M TEMPS REACHED THE MID 70S (77F AT KBTV AT
1830Z) AS EXPECTED AREAWIDE...WITH DELIGHTFULLY LOW DEWPOINTS IN
THE 30S TO LOWER 40S. WINDS HAVE ALSO BEEN RATHER LIGHT IN VCNTY
OF PREVAILING SFC ANTICYCLONE. PLEASANT CONDITIONS WILL CONTINUE
THROUGH THIS EVENING WITH TEMPERATURES FALLING THROUGH THE 60S
WITH ONSET OF DIURNAL COOLING CYCLE.
SOME GRADUAL CHANGES WILL OCCUR LATE TONIGHT. THE 850MB FRONTAL
ZONE ACROSS SRN MI/NRN OH/PA...WHICH HAS BEEN THE FOCUS FOR
SHOWER AND TSTM ACTIVITY OVER THE PAST 12-24 HRS...WILL SLOWLY
LIFT NEWD...BUT IS ALSO EXPECTED TO SLOWLY WEAKEN. AT THE SAME
TIME ...MID-LEVEL HEIGHT FALLS ARE EXPECTED ACROSS NY/VT AS
CLOSED UPR LOW OVER THE NRN GREAT LAKES BEGINS TO SHIFT INTO SERN
ONTARIO OVERNIGHT. IT SHOULD REMAIN DRY THRU MIDNIGHT ALL
SECTIONS...BUT RESULT OF THE FRONTAL ZONE AND HEIGHT FALLS
SUGGESTS WE SHOULD BEGIN TO SEE SOME ISOLD/SCT SHOWER ACTIVITY
DEVELOP ACROSS OUR NRN NY COUNTIES SEWD INTO RUTLAND COUNTY AFTER
MIDNIGHT...AND ESPECIALLY AFTER 09Z. AIR MASS WILL REMAIN QUITE
DRY FURTHER NORTH AND EAST...SO ACTIVITY SHOULD REMAIN SOUTH AND
WEST OF THE CHAMPLAIN VALLEY THRU DAYBREAK BASED ON CURRENT
INDICATIONS. LOOK FOR A GRADUALLY INCREASE IN MID AND UPPER
LEVELS CLOUDS FROM THE CHAMPLAIN VALLEY NORTH AND EASTWARD LATE.
STAYED CLOSE TO MOS CONSENSUS FOR OVERNIGHT LOWS. WITH INCREASE
IN CLOUDS LATE...WILL SEE TEMPS A BIT WARMER THAN THE PREVIOUS
COUPLE OF NIGHTS. LOWS GENERALLY IN THE UPR 40S TO LOWER
50S...EXCEPT MID 40S FOR THE NORMALLY COOLER VALLEYS WITHIN THE
NRN ADIRONDACK REGION AND ACROSS FAR NERN VT. A LIGHT S-SE WIND
WILL DEVELOP OVERNIGHT AS SFC RIDGE SLIDES EWD INTO MAINE.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 253 PM EDT WEDNESDAY...UNSETTLED WX CONDITIONS EXPECTED
THRU MUCH OF THE PERIOD. LOW-MID LEVEL LOW PRESSURE SYSTEM
ROTATES SEWD FROM SERN ONTARIO INTO THE ST. LAWRENCE VALLEY LATE
THURSDAY AFTN...AND THEN SLIDES SLOWLY SEWD ACROSS CENTRAL NEW
YORK STATE (JUST SOUTH OF THE ADIRONDACKS) AND SRN NEW ENGLAND
THURSDAY NIGHT THROUGH FRIDAY. MODELS CONTINUE TO INDICATE BEST
FOCUS FOR WIDESPREAD RAIN SHOWERS WILL BE ALONG AND JUST NORTH OF
THE 700-500MB VORT TRACK...WHICH LINES UP ACROSS OUR NRN
ADIRONDACK ZONES AND INTO S-CENTRAL VT. WITH WEAK INSTABILITY
DEVELOPING WITH COLD POOL ALOFT...FULLY EXPECT ACTIVITY TO BE
MORE WIDESPREAD DURING BOTH THURSDAY AND FRIDAY AFTN...WITH
ACTIVITY A BIT MORE CONCENTRATED NEAR THE UPR LOW DURING THE
OVERNIGHT PERIOD THURSDAY NIGHT. COULD BE COLD ENOUGH (WBZ
HEIGHTS 6-7 KFT) TO RESULT IN SOME PEA-SIZED HAIL WITH STRONGER
CORES BOTH THURSDAY AND FRIDAY AFTERNOONS. HAVE LEFT OUT SPECIFIC
MENTION OF THAT FOR NOW GIVEN WEAK INSTABILITY (<500 J/KG)...BUT
HAVE INCLUDED A SLIGHT CHANCE OF TSTMS FROM THE GREEN MTNS WWD ON
THURSDAY AFTN...AND AREAWIDE FRIDAY AFTN.
COVERAGE OF SHOWERS SHOULD DIMINISH NW-SE FRIDAY NIGHT AS UPR LOW
BEGINS TO DEPART SOUTHEAST OF NEW ENGLAND. WILL SHOW DRYING
CONDITIONS AND PARTIAL CLEARING IN THE FORECAST GRIDS FOR FRIDAY
NIGHT.
HYDROLOGICALLY...NEED TO BEWARE OF ANY POTENTIAL SURPRISE UNDER
THE UPPER LOW...BUT AT THIS POINT IT APPEARS HIGHEST RAINFALL
AMTS OF 1.0-1.5" WILL BE FOCUSED ACROSS NRN NY...AND NOT ENOUGH
TO RESULT IN FLOODING. GIVEN SATURATED CONDITIONS...THE BASIN TO
WATCH MOST CLOSELY WILL BE THE AUSABLE...WHICH ROSE TO NEAR 9
FEET (ASFN6) EARLY SUNDAY WITH THE LAST HVY RAIN PRODUCING
SYSTEM. THE RAINFALL WILL ALSO BE STRETCHED OUT ACROSS A 36-48
HOUR PERIOD. IN COMBINATION WITH ACTIVELY GROWING VEGETATION THIS
TIME OF YEAR...RUNOFF SHOULDN`T BE A SIGNIFICANT CONCERN GIVEN
CURRENT QPF EXPECTATIONS.
REMAINED CLOSE TO MOS CONSENSUS FOR DAYTIME HIGHS...GENERALLY UPR
60S TO LOWER 70S ON THURSDAY...AND MID-UPR 60S FRIDAY WITH COLD
POOL ALOFT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM EDT WEDNESDAY...AS SFC HIGH PRESSURE BUILDS OVER THE
CENTRAL GREAT LAKES REGION ON SATURDAY...AN UPPER LVL RIPPLE OF
ENERGY ALONG WITH SOME INSTABILITY WILL ALLOW FOR SCT RAIN
SHOWERS WITH PSBL TS OVER THE NORTH COUNTRY. THE SFC RIDGE WILL
SLIDE SEWD ON SUNDAY...WITH RIDING ALOFT GRADUALLY MOVING
EWD...PUTTING THE NORTH COUNTRY ON THE PERIPHERY OF HIGH
PRESSURE. THIS WILL CAUSE A DRYING TREND...BUT UPPER LVL
DISTURBANCE TRIES TO AFFECT THE AREA...SO CANNOT COMPLETELY RULE
OUT ISOLD-SCT SHOWERS OVER VT ON SUNDAY.
AS THE SFC RIDGE SLIDES INTO THE ATLANTIC OFF THE SERN USA...WE
WILL SEE A BRIEF DRY PERIOD SUNDAY NGT THROUGH MONDAY. SUNDAY
NGT...WEAKENING RIDGING ALOFT AND LOW PRESSURE SYSTEM AT THE SFC
WILL BRING ANOTHER CHANCE FOR SHOWERS...ESP ON TUESDAY.
THIS ACTIVE PATTERN WILL SEE TEMPS ABOVE NORMAL WITH GENERAL
WARMING TREND. SATURDAY...BEING THE COOLEST DAY WILL HAVE MAX
TEMPS IN THE 50S ACROSS THE MTNS AND 60S-AROUND 70 IN THE
VALLEYS. WARMEST DAY LOOKS TO BE MONDAY WITH MTNS IN THE 60S AND
VALLEYS IN THE L70S-L80S. TUESDAY AND WEDNESDAY CONTINUE TO BE
MILD. AT NIGHT...MIN TEMPS WILL RANGE FROM 40S-L50S IN THE MTNS
AND 50S IN THE VALLEYS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...EXPECTING VFR CONDITIONS FOR THE MAJORITY OF
THE PERIOD...WITH SCATTERED BRIEF PERIODS OF MVFR/IFR POSSIBLE.
SCATTERED VFR CLOUDS WITH CEILINGS 10000 FEET OR ABOVE WILL
GRADUALLY INCREASE IN COVERAGE AND LOWER THROUGH THE NIGHT AND
EARLY THURSDAY MORNING. SOME ISOLATED SHOWERS THIS EVENING AND
TONIGHT ARE POSSIBLE AT MSS/SLK/RUT BUT COVERAGE IS SO LIMITED
THAT WILL ONLY SHOW WITH VCSH FOR NOW. ADDITIONAL MORE WIDESPREAD
SHOWER AND POSSIBLE THUNDERSTORM DEVELOPMENT IS EXPECTED AFTER
14Z THURSDAY AT ALL TAF SITES. CEILINGS/VISIBILITIES WILL BE
PRIMARILY VFR...HOWEVER SOME PERIODS OF REDUCTIONS TO MVFR OR
EVEN IFR ARE POSSIBLE IN ANY HEAVIER OR MORE ORGANIZED SHOWER
ACTIVITY. WINDS WILL BE LIGHT AND LOCALLY VARIABLE
TONIGHT...BECOMING GENERALLY SOUTH/SOUTHEAST AT 5-10 KNOTS ON
THURSDAY...EXCEPT MSS WHERE NORTHEAST WINDS ARE EXPECTED THROUGH
THE PERIOD.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
00Z FRI THRU 00Z SAT...PRIMARILY VFR ALTHOUGH REDUCTIONS TO
MVFR/IFR AT TIMES IN SCATTERED SHOWERS/THUNDERSTORMS.
00Z SAT THRU 00Z MON...MAINLY VFR WITH SCATTERED MVFR SHOWERS
SATURDAY AFTERNOON...AND ISOLATED SHOWERS SUNDAY AFTERNOON.
00Z MON ONWARD...GENERALLY DRY WITH VFR CONDITIONS UNDER SFC HIGH
PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/JMG/NEILES
SHORT TERM...BANACOS
LONG TERM...KGM
AVIATION...KGM/MUCCILLI
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
143 AM EDT THU MAY 22 2014
.SYNOPSIS...
WARM AND MAINLY DRY CONDITIONS WILL CONTINUE AS HIGH PRESSURE
REMAINS TO THE SOUTH. AFTER A VERY WARM DAY THURSDAY...A COLD
FRONT WILL DROP SOUTH ON FRIDAY...AND WILL STALL JUST SOUTH OF THE
AREA THROUGH THE WEEKEND. TEMPERATURES BEHIND THIS FRONT WILL BE
COOLER...BUT SEASONABLE AND DRY CONDITIONS ARE EXPECTED INTO THE
MEMORIAL DAY HOLIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1:40 AM THURSDAY...HAVE NOT MADE ANY CHANGES TO THE FORECAST
AND WILL FOR THE MOMENT CONTINUE WITH SLIGHT CHANCE POPS FOR THE
OVERNIGHT PERIOD...BUT WILL LIKELY DROP THEM WITH THE NEXT
ISSUANCE IF CURRENT TRENDS CONTINUE. MCS DROPPING SE ACROSS THE
MOUNTAINS IS ERODING RAPIDLY AND IT IS LOOKING LESS LIKELY THAT WE
WILL GET MUCH MORE THAN SOME MID-LEVEL CLOUDS. PREVIOUS
DISCUSSIONS FOLLOW:
I HAVE TRIMMED BACK POPS A LITTLE MORE BASED MAINLY ON DATA
COLLECTED FROM THE 00Z GSO WEATHER BALLOON SHOWING A 3 DEGREE
CELSIUS INVERSION BETWEEN 11000-12000 FEET. THIS WOULD TEND TO CAP
OFF ANY CUMULUS GROWING FROM BELOW. EACH RUN OF THE HRRR MODEL
CONTINUES TO SHOW SCATTERED SHOWERS DEVELOPING AROUND MIDNIGHT
ACROSS EASTERN NC...BUT THIS SEEMS THERMODYNAMICALLY UNLIKELY
GIVEN THE WEATHER BALLOON DATA. NO OTHER SIGNIFICANT CHANGES.
PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...
SURFACE HIGH PRESSURE OFF THE FL/GA COAST IS PRODUCING A STEADY SW
BREEZE...STRONGEST NEAR THE COAST WHERE SEABREEZE INFLUENCE HAS
INCREASED WIND SPEEDS TO NEAR 20 MPH. ALOFT THE FLOW IS STRONGLY
VEERED TO THE NW AT AND ABOVE 850 MB DUE TO THE MID AND UPPER LEVEL
RIDGE STILL CENTERED BACK OVER THE LOWER MISSISSIPPI VALLEY.
THE CONCERN FOR TONIGHT IS HOW MUCH INFLUENCE THE EASTERN CAROLINAS
GET FROM A DEVELOPING MCS ACROSS THE OHIO VALLEY. MODELS ALL SHOW
THIS ACTIVITY MAKING INTO THE NC/VA MOUNTAINS LATER THIS EVENING...
BUT THE MOUNTAINS MAY TAKE THEIR TOLL ON THE STORMS AS HIGH-RES
MODEL DEPICTIONS SHOW ONLY LIMITED CONVECTION SURVIVING THROUGH THE
PIEDMONT AND COASTAL PLAIN. LAPSE RATES ALOFT ARE STEEP...TONIGHT`S
850 MB TEMP OF +17C VERSUS A 500 MB TEMP OF -11C TELLS THAT PART OF
THE STORY. COUPLED LOW AND MID LEVEL LIFT AHEAD OF AN UPPER LEVEL
DISTURBANCE EMBEDDED IN THE NW FLOW ALOFT WILL SERVE AS THE
CONVECTIVE TRIGGER...BUT THE LIMITING FACTOR WILL BE HOW MUCH
MOISTURE CAN POOL AT THE BASE OF THE STEEP LAPSE RATES NEAR 850 MB?
MODELS DEFINITELY SHOW MORE 850 MB MOISTURE ACROSS NC THAN SC...AND
GIVEN THIS LIMITED "THUNDERSTORM FUEL" OVER SC I HAVE REMOVED POPS
THERE. IF ACTIVITY CAN SURVIVE THIS FAR SOUTH AND EAST THE WINDOW OF
THUNDERSTORM POTENTIAL WILL BE FROM MIDNIGHT UNTIL 4 AM...GENERALLY
ALONG AND NORTH OF A LINE FROM BENNETTSVILLE THROUGH DILLON...
WHITEVILLE...OAK ISLAND AND SOUTHPORT.
THE PRESENCE OF PERIODS OF CIRRUS CLOUD COVER PLUS THE SOUTHWEST
BREEZE MUCH OF THE NIGHT SHOULD HELP KEEP LOWS IN THE UPPER 60S
INLAND TO NEAR 70 ON THE COAST. THIS IS A LITTLE ABOVE THE WARMEST
MOS GUIDANCE AND NEAR THE BIAS-CORRECTED GFS NUMBERS.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 240 PM WEDNESDAY...ALTHOUGH THE 500 MB RIDGE WILL REMAIN
CENTERED OVER THE GULF COAST STATES THURSDAY...IT WILL SHIFT EAST
ENOUGH TO RESULT IN HEIGHT RISES OVER THE CAROLINAS...AS WELL AS
THE EXPANSION OF UNSEASONABLY HOT AIR INTO THE AREA. MODELS STILL
INDICATE 850 MB TEMPS TO 18C AS FAR NORTH AS THE NC-SC STATE LINE.
12Z GUIDANCE IS CONSISTENT AND REMAINS IN LINE WITH GOING FORECAST
OF LOW TO MID 90S EVERYWHERE AWAY FROM THE IMMEDIATE COAST...WHERE
HIGHS ARE EXPECTED TO REACH THE MID 80S. CAN`T RULE OUT A LATE
AFTERNOON OR EVENING THUNDERSTORM GIVEN THE STRONG HEATING AND
WEAK CONVERGENCE ALONG A SURFACE TROUGH INLAND.
A 500 MB SHORTWAVE WILL HELP USHER THE TROUGH/FRONT SOUTH THROUGH
THE CWA THURSDAY NIGHT...AND SURFACE HIGH PRESSURE WILL BUILD IN
FROM THE NORTHWEST. THE SHORTWAVE WILL FLATTEN OUT THE MID-LEVEL
RIDGING OVER THE AREA...THEREFORE MAX TEMPS FRIDAY WILL FALL BACK
A FEW DEGREES. ISOLATED CONVECTION WILL REMAIN A POSSIBILITY GIVEN
ANOTHER DAY OF STRONG HEATING AND NORTHWESTERLY FLOW ALOFT.
TIME-HEIGHT CROSS SECTIONS CONTINUE TO INDICATE RAPID DRYING OF
THE COLUMN UNDERWAY BY 06Z SATURDAY. THEREFORE METEOR SHOWER
ENTHUSIASTS HAVE REASON TO BE OPTIMISTIC AS LOW/MID CLOUDS SHOULD
NOT IMPEDE VISIBILITY LATE FRIDAY NIGHT. CAN`T RULE OUT A THIN
LAYER OF CIRRUS HOWEVER.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 240 PM WEDNESDAY...FAIRLY DEEP UPPER TROUGH FORMS OFF NEW
ENGLAND COAST OVER THE WEEKEND DRIVING A VERY PLEASANT AIRMASS
INTO THE SOUTHEASTERN U.S. TEMPERATURE DEVIATIONS FROM CLIMATOLOGY
WILL BE MORE PRONOUNCED AT NIGHT THAN BY DAY...AND THE LOWERED RH
WILL BE VERY NOTICEABLE. UPPER RIDGE BUILDS OVERHEAD ON MONDAY AND
SOME LIGHT RETURN FLOW MAY GET UNDERWAY. THIS SHOULD TRANSLATE TO
A WARMING TREND AS WELL AS AN INCREASE IN DEWPOINTS/RH. A
FLATTENING OF THE RIDGE ALOFT PAIRED WITH THE FORMATION OF A
PIEDMONT TROUGH CALLS FOR LOW CHANCES OF MAINLY DIURNAL
CONVECTION. TEMPERATURES WILL BE VERY NEAR CLIMATOLOGY NEXT WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...EXPECT VFR TO PREVAIL THROUGH THE VALID TAF PERIOD.
LATEST SATELLITE IMAGERY CONTINUES TO DEPICT MID TO HIGH CLOUDS TO
THE NORTHWEST IN CORRELATION WITH THUNDERSTORM ACTIVITY SLOWLY
MOVING SOUTHEAST TOWARDS THE AREA. WHILE COULD NOT COMPLETELY RULE
OUT AN ISOLATED SHOWER OR THUNDERSTORM MUCH LATER TONIGHT INTO THE
EARLY OVERNIGHT HOURS AT KLBT/KILM PER SUGGESTION OF SOME MODEL
GUIDANCE...CONFIDENCE IS LOW GIVEN INTERACTION WITH APPALACHIAN
MOUNTAINS AND THUS DO NOT EXPECT ANY RESTRICTIONS TO OCCUR AS A
RESULT. AS FOR WINDS CAN EXPECT SOUTHWEST WINDS BECOMING AOB 10 KTS
THROUGH THE OVERNIGHT HOURS. AFTER DAYBREAK...EXPECT VFR WITH THE
POSSIBILITY OF ISOLATED TO SCATTERED AFTERNOON SHRA/TSRA. WESTERLY
WINDS WILL PREVAIL WITH SUSTAINED WINDS INCREASING TO AOB 12 KTS
WITH AFTERNOON GUSTS POSSIBLE...SUBSIDING INTO THE EVENING HOURS.
EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD.
CHANCE OF SHOWERS THURSDAY THROUGH SATURDAY MORNING WITH A COLD
FRONT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1:40 AM THURSDAY...NO SIGNIFICANT CHANGES HAVE BEEN MADE WITH
THIS UPDATE. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS:
HIGH PRESSURE EAST OF THE GA/FL COAST IS MAINTAINING A HEALTHY
SOUTHWEST WIND ACROSS THE COASTAL WATERS. ADD IN SOME EXTRA WIND
FROM THE AFTERNOON SEABREEZE AND WE`RE SEEING A SOLID 20 KNOTS
ACROSS MOST OF THE COASTAL WATERS CURRENTLY. WINDS ACROSS THE SC
WATERS SHOULD NOT INCREASE TONIGHT AND WILL ACTUALLY DIMINISH AFTER
MIDNIGHT AS WIND DIRECTIONS TURN MORE WESTERLY IN ASSOCIATION WITH
AN UPPER LEVEL DISTURBANCE PASSING THROUGH TO OUR NORTH. ACROSS THE
NC WATERS WINDS MAY INCREASE ANOTHER 3-5 KNOTS BY MIDNIGHT AHEAD OF
THE UPPER DISTURBANCE...BUT EVEN HERE SHOULD DIMINISH LATE TONIGHT
AS DIRECTIONS TURN WESTERLY.
I HAVE MAINTAINED THE SMALL CRAFT ADVISORY FOR THE NC WATERS WHERE
SEAS SHOULD BUILD TO 5-6 FEET OUT BEYOND 10 MILES FROM SHORE...
ESPECIALLY JUST EAST OF BALD HEAD ISLAND WHERE THE EFFECTIVE FETCH
LENGTH IS QUITE LONG ON A SW WIND.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 240 PM WEDNESDAY...LOW PRESSURE MOVING EAST OFF THE
DELMARVA PENINSULA WILL COMBINE WITH HIGH PRESSURE OVER THE GULF
COAST TO PRODUCE WESTERLY WINDS ACROSS THE AREA WATERS. THE
GRADIENT WILL WEAKEN THROUGH THE DAY AS THE LOW MOVES TO THE EAST.
A WEAK SURFACE TROUGH/FRONT WILL DROP SOUTH ACROSS THE WATERS
THURSDAY NIGHT RESULTING IN A SHIFT TO NORTHERLY WINDS. THE
GRADIENT WILL TEMPORARILY WASH OUT FRIDAY WITH WINDS BECOMING
VARIABLE. HIGH PRESSURE WILL PUSH ACROSS THE CAROLINAS FRIDAY
NIGHT AND RESULT IN A LATE NIGHT NORTHERLY SURGE TO 15-20 KTS.
WILL HAVE TO MONITOR THE PROGRESSION OF ANY CONVECTION THAT
DEVELOPS INLAND BOTH THURSDAY AND FRIDAY...AS DEEP NORTHWEST FLOW
COULD PUSH THIS ACTIVITY ACROSS THE COASTAL WATERS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 240 PM WEDNESDAY...N TO NE WINDS ON SATURDAY WILL FOLLOW IN
THE WAKE OF FRIDAY COLD FRONT. FLOW WILL REMAIN LIGHT...NO SURGE
OF COOLER AIR OR HIGHER PRESSURES NORMALLY ASSOCIATED WITH COOL
SEASON FROPAS. CENTER OF HIGH PRESSURE DRAWS NEARER BUT REMAINS TO
OUR NORTH ON SUNDAY LEADING TO A VEER TO AN ONSHORE/EASTERLY FLOW.
WIND SPEEDS REMAIN EXCEEDINGLY LIGHT BUT WILL SEE A LOCALIZED
ACCELERATION OF A FEW KNOTS ALONG THE IMMEDIATE COAST DUE TO SEA
BREEZE CIRCULATION. VEERING WINDS/CLOCKWISE CHANGE IN DIRECTION
CONTINUES INTO MONDAY AS THE CENTER OF THE HIGH PROGRESSES
EASTWARD. NOT SEEING ANY APPRECIABLE INCREASE IN WIND SPEED BUT
THE LONGER FETCH SETTING UP MAY ALLOW FOR A VERY MINOR SWELL
COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
AMZ250-252.
&&
$$
SYNOPSIS...SHK
NEAR TERM...SHK
SHORT TERM...CRM
LONG TERM...MBB
AVIATION...SGL
MARINE...MBB/SHK/CRM
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
336 AM EDT THU MAY 22 2014
.SHORT TERM (TODAY THROUGH SUNDAY)...NEAR TERM...A COMPLEX OF
SHOWERS AND THUNDERSTORMS OVER NORTHERN KENTUCKY/SOUTHERN INDIANA.
THE LATEST RAP WEAKENS THIS ACTIVITY AS IT MOVES TOWARD THE
FORECAST AREA...HOWEVER...CONVECTION STILL REMAINS STRONG. WE WILL
MONITOR THIS ACTIVITY THE REST OF THE MORNING FOR POSSIBLE UPDATE
FOR MORNING POPS.
AN OUTFLOW BOUNDARY REMAINS BETWEEN KNOXVILLE AND MORRISTOWN. THIS
BOUNDARY AS WELL AS BOUNDARY FROM KENTUCKY CONVECTION WILL LIKELY
BE MAIN FOCUS FOR AFTERNOON RE-DEVELOPMENT. AIRMASS MOST OF THE
AREA...ESPECIALLY TENNESSEE...WILL BECOME QUITE UNSTABLE WITH
MLCAPES OF 2500-3000 J/KG. FORECAST SOUNDINGS SHOW FAIRLY LARGE
HAIL CAPES WITH FAVORABLE WET BULB ZERO HEIGHTS FOR LARGE HAIL...
UP TO GOLFBALL SIZE. ALSO...FAVORABLE THERMODYNAMICS AND SOME WINDS
ALOFT FOR DAMAGING WINDS AS WELL...FOR THIS AFTERNOON AND EVENING.
A COLD FRONT WILL MOVE SOUTH ACROSS THE AREA TONIGHT AND FRIDAY
WITH ANOTHER ROUND OF ISOLATED STRONG CONVECTION AGAIN FOR THE
SOUTHEAST TENNESSEE AND SOUTHWEST NORTH CAROLINA.
FRONTAL BOUNDARY MOVES SOUTH OF THE AREA FOR SATURDAY...THEN
DISSIPATES BY SUNDAY. SOME MOISTURE RETURN FOR SUNDAY TO INCLUDE
SLIGHT POPS FOR THE SOUTHERN AREAS DURING THE AFTERNOON/EVENING.
GENERALLY FOLLOWED THE GFS MOS...EXCEPT FOR THE NORTHERN HALF OF
THE AREA TODAY. WENT A COUPLE DEGREES COOLER DUE TO EXPECTED
CONVECTION AND CLOUDS.
.LONG TERM (SUNDAY NIGHT THROUGH WEDNESDAY)...MODELS ARE IN GENERAL
AGREEMENT WITH THE SYNOPTIC-SCALE PATTERN FOR NEXT WEEK...AND REVEAL
AN UNSEASONABLY WARM AND HUMID AIR MASS OVER THE FORECAST AREA WITH
A WEAKENING UPPER-LEVEL TROUGH APPROACHING FROM THE PLAINS. ISOLATED
CONVECTION IS EXPECTED ON SUNDAY NIGHT AND MONDAY...WITH THE
APPROACHING UPPER-LEVEL TROUGH HELPING TO INCREASE THE AREAL
COVERAGE OF CONVECTION BY TUESDAY INTO WEDNESDAY. AS FOR TEMPS...
WILL GENERALLY TREND CLOSE TO THE GFS GUIDANCE NUMBERS FOR NEXT
WEEK...WHICH ARE IN GOOD AGREEMENT WITH THE ENSEMBLE MEANS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 89 66 87 61 / 20 20 30 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 86 63 84 57 / 60 20 20 10
OAK RIDGE, TN 87 63 84 56 / 60 20 20 10
TRI CITIES AIRPORT, TN 83 57 80 48 / 40 20 10 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1001 AM MDT THU MAY 22 2014
.UPDATE...
ISSUED AT 1001 AM MDT THU MAY 22 2014
MOSTLY SUNNY SKIES THIS MORNING AND SLIGHTLY WARMER TEMPERATURES
ALOFT ALLOW TEMPERATURES TO BE WARMER TODAY. LOOKING LIKE HIGHS
WILL BE IN THE LOWER TO MID 70S FOR MOST OF THE AREA TODAY. THESE
TEMPERATURES COMBINED WITH DEW POINTS IN THE UPPER 40S TO LOWER
50S WILL YIELD CAPES OF 1000-2000 J/KG. PLENTY OF INSTABILITY FOR
SEVERE STORMS AGAIN. MID LEVEL WINDS HAVE DECREASED...THUS SHEAR
WILL BE LESS TODAY. THIS WILL REDUCE THE THREAT FOR LONG LIVED
SUPERCELLS. STILL A THREAT FOR LARGE HAIL AND DAMAGING WINDS. IF A
TORNADO WHERE TO FORM...BEST CHANCE WILL BE ALONG A BOUNDARY THAT
IS FORECASTED TO SET UP JUST SOUTH OF DENVER...OR ALONG ANY
OUTFLOW BOUNDARY THAT INTERACTS WITH AN UPDRAFT.
LATEST HRRR MODEL SHOWS THE GREATEST STORM COVERAGE ALONG AND
SOUTH OF INTERSTATE 70. INCREASED POPS FOR THIS AREA THIS
AFTERNOON AND EARLY EVENING. BECAUSE OF THE WEAKER WINDS
ALOFT...STORMS WILL BE MOVING SLOWER TODAY. THIS WILL INCREASE THE
THREAT FOR HEAVY RAIN AND LOCALIZED FLOODING.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 305 AM MDT THU MAY 22 2014
THE UPPER LEVEL LOW WILL REMAIN OVER THE SWRN US THROUGH TONIGHT AS
A SERIES OF WEAK DISTURBANCES MOVE NNE AHEAD OF THE SYSTEM ACROSS
COLORADO. APPEARS ONE SUCH FEATURE MAY TRACK ACROSS THE AREA THIS
AFTN WHILE ANOTHER MOVES INTO THE AREA LATE TONIGHT. AT THE SFC
WILL PROBABLY SEE A SFC LOW DVLP IN THE SRN FOOTHILLS WITH A
CONVERGENCE ZONE SETTING UP OVER THE PALMER DIVIDE WITH ELY LOW LVL
FLOW FM DENVER NORTH TO THE WY BORDER. SFC BASED CAPES BY AFTN WILL
RANGE FM 1500-2000 J/KG FM THE FOOTHILLS ACROSS THE PLAINS EXCEPT
OVER THE NERN CORNER WHERE CAPES MAY STAY BLO 1000 J/KG. OVERALL
MID LVL FLOW IS FCST TO BE WEAKER TODAY SO SHEAR PROFILE WILL NOT BE
AS STRONG. HOWEVER STILL EXPECT A FEW SVR STORMS THIS AFTN INTO THE
EARLY EVENING HOURS WITH A FEW BRIEF TORNADOS POSSIBLE ALONG THE
CONVERGENCE ZN. AT THIS TIME BEST POTENTIAL FOR SVR WEATHER LOOKS
TO BE ALONG AND SOUTH OF A LINE FROM DENVER INTO SRN WASHINGTON
COUNTY UNLESS CONVERGENCE ZN SHIFTS FURTHER NORTH.
PRECIPITABLE WATER VALUES HAVE BEEN SLOWLY INCREASING AND COULD BE
NEAR AN INCH BY LATER THIS AFTN AND WITH SLOWER STORM MOTIONS THERE
WILL BE THE POTENTIAL FOR HEAVIER RAINFALL. AT THIS POINT IT
APPEARS MOST OF THE HEAVIER RAINFALL WILL BE AT LOWER ELEVATIONS
ALTHOUGH THERE COULD BE SOME HEAVY RAIN IN THE FOOTHILLS DUE TO THE
ELY LOW LVL FLOW. AS FOR TEMPS WILL KEEP READINGS MOSTLY IN THE
LOWER TO MID 70S OVER NERN CO ALTHOUGH THE RAP SUGGEST READINGS OVER
THE NERN CORNER MAY STAY IN THE 60S DUE TO EXTENSIVE LOW CLOUDS.
FOR TONIGHT STORMS OVER THE PLAINS WILL LIKELY EVOLVE INTO AN MCS
AND MOVE EASTWARD INTO THE CNTRL HIGH PLAINS THIS WILL HAVE HIGHER
POPS THIS EVENING FROM SOUTH OF AKRON TO LIMON. LATER TONIGHT
ANOTHER DISTURBANCE MAY MOVE ACROSS THE AREA WHICH COULD INCREASE
THE CHC FOR SHOWERS AND A FEW TSTMS AFTER MIDNIGHT. FOR NOW WILL
JUST KEEP POPS IN THE CHC CATEGORY DUE TO UNCERTAINTY WITH TIMING OF
THIS FEATURE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 305 AM MDT THU MAY 22 2014
SOUTHERLY FLOW ALOFT WILL CONTINUE FRIDAY WITH LOWER LEVEL
SOUTHEASTERLY UPSLOPE FLOW. SHOWERS ARE EXPECTED TO BE ONGOING IN
THE MORNING WITH A FEW THUNDERSTORMS POSSIBLE. OVERALL...CAPES
WILL BE LOWER AS UPPER LEVELS WARM SLIGHTLY AND LOWER LEVELS
REMAIN SLIGHTLY COOLER DURING THE DAY AS CLOUD-COVER WILL PREVAIL
THROUGH THE DAY. CAPE VALUES OF 250-700 J/KG ARE EXPECTED OVER THE
DAY...WITH THE HIGHEST VALUES OVER THE EASTERN PLAINS. SLOW STORM
MOTION EXPECTED THAT DAY SO LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY WHERE THE LOW LEVEL UPSLOPE FLOW PUSHES
AGAINST THE FOOTHILLS AND HIGHER TERRAIN. GIVEN THE LOWER CAPES
NEAR THE FOOTHILLS THOUGH...STORMS ARE NOT EXPECTED TO GET THAT
STRONG. WILL STILL BE ON ALERT WITH INCREASED MOISTURE SURGE FROM
THE SOUTH TO WATCH FOR POTENTIAL HEAVY RAIN. COULD SEE SOME SMALL
HAIL ACROSS THE PLAINS.
ACTIVITY WILL LIKELY CONTINUE...ALTHOUGH AT A DECREASED RATE
OVERNIGHT. THE UPPER LOW WILL LIFT NORTHEAST TOWARD THE STATE
SATURDAY WITH SLIGHTLY INCREASED FLOW ALOFT. EXPECT CONTINUED
SHOWERS AND THUNDERSTORMS ACROSS THE AREA WITH LOCALLY HEAVY
RAINFALL AND SMALL HAIL THE MAIN CONCERNS AGAIN AS CAPES REMAIN IN
THE 250-500 J/KG. AN DRIER AREA SHOWN IN ALL MODELS WILL MOVE UP
INTO EASTERN COLORADO SATURDAY NIGHT TO SUBSTANTIALLY DRY
CONDITIONS AND POSSIBLE STOP ALL SHOWER ACTIVITY OVERNIGHT...THE
FIRST TIME IN SEVERAL NIGHTS.
THE UPPER LOW IS PROGGED TO MOVE EAST OVER SOUTHEASTERN COLORADO.
IF THE PREVIOUSLY MENTIONED DRY AREA IS STILL OVER THE AREA...MAY
NOT SEE MUCH ACTIVITY OVER THE PLAINS WHILE THE MOUNTAINS WILL
CONTINUE TO SEE SCATTERED SHOWERS AND THUNDERSTORMS. A COUPLE OF
THE MODELS ARE SHOWING A HEALTHY BAND OF PRECIPITATION FORM ON THE
BACKSIDE OF THE LOW OVER WESTERN COLORADO AND THE MOUNTAINS...WILL
CONTINUE FOLLOWING THIS SOLUTION. THE UPPER LOW WILL THEN MOVE
EAST INTO THE TX/OK PANHANDLES TO ALLOW FOR UPPER RIDGING MONDAY
AND TUESDAY...BRINGING WARMER AND DRIER CONDITIONS. COULD STILL
SEE ISOLATED TO SCATTERED SHOWERS MONDAY WHILE THE SYSTEM MOVES
FURTHER AWAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1001 AM MDT THU MAY 22 2014
STILL ON TRACK TO SEE ANOTHER ROUND OF THUNDERSTORMS BETWEEN 2000Z
AND 2400Z. STORMS MAY BRING SOME HAIL TO ONE INCH IN DIAMETER
ALONG WITH HEAVY RAINFALL. EXPECT MOST OF THE ACTIVITY WILL MOVE
EAST OF DIA BY 0000Z WITH IMPROVING CONDITIONS. WINDS ARE EXPECTED
TO BECOME EAST LATE THIS MORNING. ONCE STORMS FORM...OUTFLOW
BOUNDARIES WILL MOVE ACROSS CAUSING VARIABLE WIND DIRECTIONS. BY
THIS EVENING...WINDS WILL TURN MORE SOUTHEAST. ANOTHER
DISTURBANCE MAY MOVE ACROSS LATE TONIGHT BRINGING A CHANCE OF
SHOWERS AND POSSIBLY A THUNDERSTORM. MORE LOW CLOUDS AND POSSIBLY
FOG ARE EXPECTED FRIDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 305 AM MDT THU MAY 22 2014
STORMS THIS AFTERNOON WILL BE SLOWER MOVING SO THERE WILL BE A
HIGHER POTENTIAL FOR HEAVY RAINFALL IN SOME AREAS WITH UP TO 2
INCHES IN 45 MINUTES OR LESS. THE HEAVIEST RAINFALL WILL STAY OVER
THE PLAINS ALTHOUGH THERE COULD BE SOME SLOW MOVING TSTMS IN THE
FOOTHILLS WHICH COULD PRODUCE UP TO AN INCH OF RAIN IN 30 MINUTES IN
A FEW LOCATIONS.
STILL KEEPING A WATCHFUL EYE ON FRIDAY AND SATURDAY FOR HEAVY
RAINFALL FROM STORMS AS THE MOISTURE SURGE MOVES INTO THE STATE
FROM THE SOUTH. INSTABILITY WILL BE WEAKER BUT STILL EXPECTING
SLOWER MOVING STORMS. UPSLOPE FLOW SEEMS TO BE SLIGHTLY WEAKENING
AND A SURFACE TROUGH MAY ALTER THE UPSLOPE FLOW TO LITTLE OR NONE
AT TIMES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MEIER
SHORT TERM...RPK
LONG TERM...KRIEDERMAN
AVIATION...MEIER
HYDROLOGY...KRIEDERMAN/RPK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1101 AM CDT THU MAY 22 2014
.DISCUSSION...
306 AM CDT
A QUIET END TO THIS WEEK OFFERS MAINLY ONLY TEMPERATURE FORECAST
CHALLENGES. WHILE THERE ARE SMALL CHANCES OF THUNDERSTORMS FORECAST
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK...THE REGIME FORECAST IS
ONE THAT KEEPS THE PROBABILITY LOW OF ANY HIGH IMPACT WEATHER THROUGH
THE HOLIDAY.
TODAY...
AN UPPER LOW ACROSS EASTERN ONTARIO THIS MORNING WILL CONTINUE TO
USHER A SURFACE COLD FRONT SOUTH FROM CENTRAL ILLINOIS AND INDIANA
TODAY. DAMPENED UPPER RIDGING WILL REMAIN IN PLACE FROM THE SOUTHERN
U.S. THROUGH THE MISSOURI RIVER VALLEY TODAY. WITH A STRONG UPPER
JET BETWEEN THESE TWO UPPER FEATURES...BROAD WEAK ASCENT WITHIN THE
RIGHT ENTRANCE REGION AND A SHEARED SHORT WAVE SHOULD SUPPORT HIGH
CLOUDS TO SPREAD ACROSS THE FORECAST AREA LATE THIS MORNING INTO THE
AFTERNOON. THIS IS LIKELY TO BE THICKER IN THE SOUTHERN FORECAST
AREA AND HAVE INCREASED FORECAST CLOUD COVER MORE SO THERE...BUT AT
LEAST SOME AREA WIDE. TEMPERATURES WILL LIKELY BE EFFECTED SLIGHTLY
BY THIS...ALTHOUGH COOLING WITHIN/AT THE TOP OF THE MIXED LAYER FROM
YESTERDAY WILL BE THE PRIMARY REASON FOR COOLER HIGHS. ONSHORE FLOW
WILL DEVELOP BY MID-MORNING WITH COOLER TEMPERATURES NEAR THE LAKE.
EXPECT THAT THE THERMAL DIFFERENCE BETWEEN DOWNTOWN CHICAGO AND FAR
WESTERN SUBURBS TO BE 10-12 DEGREES...NEAR THE LATE MAY CLIMO NORMAL
WITH ONSHORE FLOW ALL DAY.
TONIGHT THROUGH FRIDAY NIGHT...
A SURFACE HIGH WILL CENTER OVER THE AREA OFFERING LIGHT WIND FLOW.
BY LATE THIS EVENING AND THROUGH THIS PERIOD THERE LOOKS TO BE
LITTLE IN THE WAY OF CLOUDS. ONSHORE FLOW WILL REDEVELOP DURING
FRIDAY KEEPING LAKESIDE AREAS IN THE LOWER 60S OR SO. BOTH NIGHTS
LOOK TO SUPPORT 40S FOR LATE NIGHT LOWS IN THE MOST AREAS...WITH
SOME OF THE COOLER SPOTS REALIZING LOWER 40S ON FRIDAY NIGHT.
THE HOLIDAY WEEKEND INTO NEXT WEEK...
THE MEANDERING UPPER LOW ACROSS THE SOUTHWEST U.S. WILL DRIFT
NORTHEAST AS A RESULT OF BEING DISJOINTED FROM THE STRONGER WESTERLY
JET ACROSS THE U.S./CANADIAN BORDER. SUCH A CLOSED FEATURE IN THAT
PATTERN SEEMS TO MORE OFTEN THAN NOT MOVE SLOWER THAN INITIALLY
DEPICTED BY LONG RANGE GUIDANCE. WARM ADVECTION AND PRECIPITABLE
WATER INCREASE ARE FORECAST TO OCCUR SUNDAY AND MOST DETERMINISTIC
AND ENSEMBLE GUIDANCE HINT AT SOME CHANCE OF PRECIPITATION IN THE
REGION...THOUGH MAINLY NORTHWEST OF THE AREA. THE UPPER RIDGE IS
FORECAST TO RE-AMPLIFY OVER THE AREA ON THE HOLIDAY WITH A WEAK
SURFACE FRONT TO THE NORTH. IF THAT PATTERN WERE TO UNFOLD...THUNDER
CHANCES LOOK MINIMAL OVER THE FORECAST AREA. HAVE DECREASED THE
COVERAGE AND MAGNITUDE OF POPS PROVIDED BY A MODEL/PREVIOUS FORECAST
BLEND FOR THE HOLIDAY AND TUESDAY. THE UPPER LOW OR OPEN WAVE SHOULD
SHIFT EAST DURING THE MIDDLE OF THE WEEK...THOUGH THE 22.00 GFS
ACTUALLY TURNS THIS SOUTHEAST WITH BASICALLY VERY LITTLE PRECIP
CHANCES DURING MIDWEEK. WHILE THAT SEEMS A LITTLE SUSPECT...THE
CHANCES FOR RAIN LOOK SMALL AT THIS DISTANCE.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NELY-ELY WINDS WITH SUSTAINED SPEEDS LESS THAN 10 KT THROUGH
EARLY EVENING.
* NORTHEAST WINDS FRIDAY.
KREIN
//DISCUSSION...UPDATED 12Z...
NO SIGNIFICANT AVIATION IMPACTS OVER THE NEXT 24 TO 30 HOURS UNDER
THE INFLUENCE OF DRY CANADIAN HIGH PRESSURE WITH VFR CONDITIONS
THROUGHOUT. LIGHT NORTHERLY WINDS EARLY THIS MORNING ARE EXPECTED
TO QUICKLY VEER NORTHEAST BY MID TO LATE MORNING AT ORD/MDW/GYY
WITH LAKE BREEZE PROBABLY MAKING IT TO DPA IN MID TO LATE
AFTERNOON. WINDS AT ORD/MDW/GYY ARE LIKELY TO VEER MORE TOWARD
EAST NORTHEAST OR EAST BY MID TO LATE AFTERNOON. SUSTAINED SPEEDS
AT ORD/MDW SHOULD AT LEAST OCCASIONALLY BE AROUND 10 KT FROM MID-
LATE AM THROUGH EARLY THIS EVENING. WINDS IN NORTH CENTRAL
ILLINOIS INCLUDING RFD WILL BACK FROM NORTHERLY TO NORTHWEST BY
MID DAY. LIGHT AND VARIABLE WINDS ARE EXPECTED AFTER SUNSET THIS
EVENING AS RIDGE AXIS MOVES OVERHEAD. LIGHT NORTH AND NORTHEAST
WINDS EARLY FRIDAY MORNING WILL LIKELY BECOME NORTHEAST AT ALL
TERMINALS AND INCREASE SOME BY MID TO LATE MORNING.
RC
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR. EARLY EVE NORTHEAST WINDS LIKELY BECOME LIGHT/VRB.
SATURDAY...VFR. EASTERLY WINDS THROUGH EVENING.
SUNDAY...SCHC TSRA...OTHERWISE MAINLY VFR.
MONDAY...CHC TSRA...OTHERWISE MAINLY VFR.
TUESDAY...SCHC TSRA...OTHERWISE MAINLY VFR. NE WIND SHIFT PSBL.
WEDNESDAY...CHC TSRA. NORTHEAST WINDS PSBL.
RC
&&
.MARINE...
301 AM CDT
EXPANSIVE HIGH PRESSURE SPREADING SOUTHEAST FROM THE UPPER MIDWEST
ACROSS THE GREAT LAKES REGION TODAY THROUGH SATURDAY WILL RESULT
IN AN EXTENDED PERIOD OF FAIRLY LIGHT WINDS AND LOW WAVES. WINDS
WILL INITIALLY BE NORTH AND NORTHWEST BUT TREND TOWARD GREATER
VARIABILITY LATER TODAY THROUGH SATURDAY AS THE HIGH BECOMES
PRIMARILY CENTERED OVER LAKE MICHIGAN. WINDS IN THE NEARSHORE
AREAS WILL BE CONTROLLED BY LAKE BREEZE INFLUENCES.
THE HIGH WILL THEN SLIDE EAST SUNDAY AND OFF THE ATLANTIC COAST ON
SUNDAY NIGHT...RESULTING IN INCREASING SOUTHERLY WINDS. AS BROAD
LOW PRESSURE OVER THE PLAINS AND CANADIAN PRAIRIES ON SUNDAY
CONSOLIDATES INTO A LOW CENTER NORTH OF THE LAKES ON
MONDAY...GUSTS COULD REACH UP TO 25 KT FOR A PERIOD LATE SUNDAY
INTO MONDAY DESPITE A VERY WARM AIR MASS MOVING OVER THE LAKE.
WITH THIS WARM AND MOIST AIR MASS WILL ALSO COME AN INCREASING
CHANCE FOR THUNDERSTORMS LATE SUNDAY THROUGH MONDAY EVENING.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
1054 AM CDT Thu May 22 2014
.DISCUSSION...
ISSUED 1046 AM CDT Thu May 22 2014
High pressure building back into the region and a more stable
airmass dominating. MCS remnants to the west running into a drier
airmass as well and precip is dwindling as it crosses the
Mississippi River. Expect the trend to continue. Keeping the
forecast mainly dry with a slight chance mention for the west this
afternoon, though a stray sprinkle or two may remain possible
through the late morning hours. Forecast temperatures are on track
under mostly cloudy skies as plenty of mid clouds stream into the
FA remnants of the MCS. No updates are anticipated at this time.
HJS
&&
.AVIATION...
ISSUED 655 AM CDT Thu May 22 2014
VFR conditions should prevail across the central IL airports
through 12Z/7 am Friday. Mid and high clouds to spread ese across
central IL during the day as ceilings lower to 7-12k ft. These
clouds will then scatter out from north to south during overnight
occurring near I-74 first. Isolated showers and thunderstorms
should stay sw of SPI this afternoon and evening. Thunderstorms
with MCS over nw MO, ne KS, se NE and sw IA and associated with a
short wave to track ese across northern MO and sw IL today and
evening along frontal boundary that has pushed south of I-70 early
this morning and will continue to stay south of central IL thru
tonight. NNW winds will be near 10 kts today and veer NNE tonight
and diminish to around 5 kts.
07
&&
.PREV DISCUSSION...
ISSUED 319 AM CDT Thu May 22 2014
SHORT TERM...Today through Saturday
07z/2am surface analysis shows cold front extending from near
Paris to just south of Taylorville. Ahead of the boundary, a
warm/humid airmass persists across southeast Illinois where
dewpoints are in the middle to upper 60s. Meanwhile behind the
front, northerly winds have brought considerably drier air into
much of central Illinois, with dewpoints dropping into the upper
40s and lower 50s north of I-72. Front will continue to sag
southward today, eventually dropping south of the Ohio River by
late afternoon. As a result, cooler and less humid conditions can
be expected with high temps remaining in the 70s. Precip chances
will develop along/ahead of the front this afternoon, but will
remain south of the KILX CWA. The only potential fly in the
ointment will be a weak short-wave currently tracking out of
Colorado. As this feature approaches from the west, a few
showers/storms may spread into the far W/SW CWA this afternoon and
evening. While most models keep central Illinois completely dry
today and tonight, higher-res models such as the RAP and HRRR show
precip associated with the wave moving across central/southern
Iowa and approaching from the west this afternoon. Have therefore
included a slight chance POP along/southwest of a Rushville to
Jacksonville line this afternoon into tonight.
High pressure will build into the southern Great Lakes by the end
of the week, pushing the front even further south/southwest. With
dry N/NE flow around the high, sunny skies will be the rule on
both Friday and Saturday with temperatures in the 70s and low
relative humidity values.
LONG TERM...Sunday through Wednesday
As high slides off to the east, remnants of old frontal boundary
will return northward on Sunday. Models continue to produce some
QPF across the area as the warmer air returns: however, with only
meager forcing along a dissipating boundary and rising upper heights,
think this is overdone. Upper ridge will build in earnest across
the Midwest early next week, leading to temperatures climbing well
into the 80s. Big question will be how fast the ridge breaks down
as cut-off low currently over southern California works its way
eastward. GFS has been the slowest model with this process for the
past few runs and its 00z May 22 solution is no exception.
Meanwhile, ECMWF had previously been faster, but its latest run
has slowed down and now keeps wave west of Illinois until
Wednesday. Given high-amplitude upper ridge in place over the
Midwest, continue to favor a slower solution. Even though both the
GFS and ECMWF delay the arrival of the upper low until mid-week,
both produce QPF across the area on Monday and Tuesday. Given high
upper heights and lack of forcing, think little more than isolated
diurnal convection will fire on either of those two days. As such,
have kept the forecast dry until Wednesday when better forcing
arrives with the approaching upper low.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
901 AM CDT THU MAY 22 2014
.DISCUSSION...
306 AM CDT
A QUIET END TO THIS WEEK OFFERS MAINLY ONLY TEMPERATURE FORECAST
CHALLENGES. WHILE THERE ARE SMALL CHANCES OF THUNDERSTORMS FORECAST
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK...THE REGIME FORECAST IS
ONE THAT KEEPS THE PROBABILITY LOW OF ANY HIGH IMPACT WEATHER THROUGH
THE HOLIDAY.
TODAY...
AN UPPER LOW ACROSS EASTERN ONTARIO THIS MORNING WILL CONTINUE TO
USHER A SURFACE COLD FRONT SOUTH FROM CENTRAL ILLINOIS AND INDIANA
TODAY. DAMPENED UPPER RIDGING WILL REMAIN IN PLACE FROM THE SOUTHERN
U.S. THROUGH THE MISSOURI RIVER VALLEY TODAY. WITH A STRONG UPPER
JET BETWEEN THESE TWO UPPER FEATURES...BROAD WEAK ASCENT WITHIN THE
RIGHT ENTRANCE REGION AND A SHEARED SHORT WAVE SHOULD SUPPORT HIGH
CLOUDS TO SPREAD ACROSS THE FORECAST AREA LATE THIS MORNING INTO THE
AFTERNOON. THIS IS LIKELY TO BE THICKER IN THE SOUTHERN FORECAST
AREA AND HAVE INCREASED FORECAST CLOUD COVER MORE SO THERE...BUT AT
LEAST SOME AREA WIDE. TEMPERATURES WILL LIKELY BE EFFECTED SLIGHTLY
BY THIS...ALTHOUGH COOLING WITHIN/AT THE TOP OF THE MIXED LAYER FROM
YESTERDAY WILL BE THE PRIMARY REASON FOR COOLER HIGHS. ONSHORE FLOW
WILL DEVELOP BY MID-MORNING WITH COOLER TEMPERATURES NEAR THE LAKE.
EXPECT THAT THE THERMAL DIFFERENCE BETWEEN DOWNTOWN CHICAGO AND FAR
WESTERN SUBURBS TO BE 10-12 DEGREES...NEAR THE LATE MAY CLIMO NORMAL
WITH ONSHORE FLOW ALL DAY.
TONIGHT THROUGH FRIDAY NIGHT...
A SURFACE HIGH WILL CENTER OVER THE AREA OFFERING LIGHT WIND FLOW.
BY LATE THIS EVENING AND THROUGH THIS PERIOD THERE LOOKS TO BE
LITTLE IN THE WAY OF CLOUDS. ONSHORE FLOW WILL REDEVELOP DURING
FRIDAY KEEPING LAKESIDE AREAS IN THE LOWER 60S OR SO. BOTH NIGHTS
LOOK TO SUPPORT 40S FOR LATE NIGHT LOWS IN THE MOST AREAS...WITH
SOME OF THE COOLER SPOTS REALIZING LOWER 40S ON FRIDAY NIGHT.
THE HOLIDAY WEEKEND INTO NEXT WEEK...
THE MEANDERING UPPER LOW ACROSS THE SOUTHWEST U.S. WILL DRIFT
NORTHEAST AS A RESULT OF BEING DISJOINTED FROM THE STRONGER WESTERLY
JET ACROSS THE U.S./CANADIAN BORDER. SUCH A CLOSED FEATURE IN THAT
PATTERN SEEMS TO MORE OFTEN THAN NOT MOVE SLOWER THAN INITIALLY
DEPICTED BY LONG RANGE GUIDANCE. WARM ADVECTION AND PRECIPITABLE
WATER INCREASE ARE FORECAST TO OCCUR SUNDAY AND MOST DETERMINISTIC
AND ENSEMBLE GUIDANCE HINT AT SOME CHANCE OF PRECIPITATION IN THE
REGION...THOUGH MAINLY NORTHWEST OF THE AREA. THE UPPER RIDGE IS
FORECAST TO RE-AMPLIFY OVER THE AREA ON THE HOLIDAY WITH A WEAK
SURFACE FRONT TO THE NORTH. IF THAT PATTERN WERE TO UNFOLD...THUNDER
CHANCES LOOK MINIMAL OVER THE FORECAST AREA. HAVE DECREASED THE
COVERAGE AND MAGNITUDE OF POPS PROVIDED BY A MODEL/PREVIOUS FORECAST
BLEND FOR THE HOLIDAY AND TUESDAY. THE UPPER LOW OR OPEN WAVE SHOULD
SHIFT EAST DURING THE MIDDLE OF THE WEEK...THOUGH THE 22.00 GFS
ACTUALLY TURNS THIS SOUTHEAST WITH BASICALLY VERY LITTLE PRECIP
CHANCES DURING MIDWEEK. WHILE THAT SEEMS A LITTLE SUSPECT...THE
CHANCES FOR RAIN LOOK SMALL AT THIS DISTANCE.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHEAST WINDS WITH SUSTAINED SPEEDS LESS THAN 10 KT BY MID-
LATE MORNING VEERING MORE EASTERLY DURING AFTN.
* NORTHEAST WINDS FRIDAY.
KREIN
//DISCUSSION...UPDATED 12Z...
NO SIGNIFICANT AVIATION IMPACTS OVER THE NEXT 24 TO 30 HOURS UNDER
THE INFLUENCE OF DRY CANADIAN HIGH PRESSURE WITH VFR CONDITIONS
THROUGHOUT. LIGHT NORTHERLY WINDS EARLY THIS MORNING ARE EXPECTED
TO QUICKLY VEER NORTHEAST BY MID TO LATE MORNING AT ORD/MDW/GYY
WITH LAKE BREEZE PROBABLY MAKING IT TO DPA IN MID TO LATE
AFTERNOON. WINDS AT ORD/MDW/GYY ARE LIKELY TO VEER MORE TOWARD
EAST NORTHEAST OR EAST BY MID TO LATE AFTERNOON. SUSTAINED SPEEDS
AT ORD/MDW SHOULD AT LEAST OCCASIONALLY BE AROUND 10 KT FROM MID-
LATE AM THROUGH EARLY THIS EVENING. WINDS IN NORTH CENTRAL
ILLINOIS INCLUDING RFD WILL BACK FROM NORTHERLY TO NORTHWEST BY
MID DAY. LIGHT AND VARIABLE WINDS ARE EXPECTED AFTER SUNSET THIS
EVENING AS RIDGE AXIS MOVES OVERHEAD. LIGHT NORTH AND NORTHEAST
WINDS EARLY FRIDAY MORNING WILL LIKELY BECOME NORTHEAST AT ALL
TERMINALS AND INCREASE SOME BY MID TO LATE MORNING.
RC
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN ALL OTHER ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR. EARLY EVE NORTHEAST WINDS LIKELY BECOME LIGHT/VRB.
SATURDAY...VFR. EASTERLY WINDS THROUGH EVENING.
SUNDAY...SCHC TSRA...OTHERWISE MAINLY VFR.
MONDAY...CHC TSRA...OTHERWISE MAINLY VFR.
TUESDAY...SCHC TSRA...OTHERWISE MAINLY VFR. NE WIND SHIFT PSBL.
WEDNESDAY...CHC TSRA. NORTHEAST WINDS PSBL.
RC
&&
.MARINE...
301 AM CDT
EXPANSIVE HIGH PRESSURE SPREADING SOUTHEAST FROM THE UPPER MIDWEST
ACROSS THE GREAT LAKES REGION TODAY THROUGH SATURDAY WILL RESULT
IN AN EXTENDED PERIOD OF FAIRLY LIGHT WINDS AND LOW WAVES. WINDS
WILL INITIALLY BE NORTH AND NORTHWEST BUT TREND TOWARD GREATER
VARIABILITY LATER TODAY THROUGH SATURDAY AS THE HIGH BECOMES
PRIMARILY CENTERED OVER LAKE MICHIGAN. WINDS IN THE NEARSHORE
AREAS WILL BE CONTROLLED BY LAKE BREEZE INFLUENCES.
THE HIGH WILL THEN SLIDE EAST SUNDAY AND OFF THE ATLANTIC COAST ON
SUNDAY NIGHT...RESULTING IN INCREASING SOUTHERLY WINDS. AS BROAD
LOW PRESSURE OVER THE PLAINS AND CANADIAN PRAIRIES ON SUNDAY
CONSOLIDATES INTO A LOW CENTER NORTH OF THE LAKES ON
MONDAY...GUSTS COULD REACH UP TO 25 KT FOR A PERIOD LATE SUNDAY
INTO MONDAY DESPITE A VERY WARM AIR MASS MOVING OVER THE LAKE.
WITH THIS WARM AND MOIST AIR MASS WILL ALSO COME AN INCREASING
CHANCE FOR THUNDERSTORMS LATE SUNDAY THROUGH MONDAY EVENING.
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
National Weather Service Lincoln IL
658 AM CDT Thu May 22 2014
.DISCUSSION...
ISSUED 319 AM CDT Thu May 22 2014
SHORT TERM...Today through Saturday
07z/2am surface analysis shows cold front extending from near
Paris to just south of Taylorville. Ahead of the boundary, a
warm/humid airmass persists across southeast Illinois where
dewpoints are in the middle to upper 60s. Meanwhile behind the
front, northerly winds have brought considerably drier air into
much of central Illinois, with dewpoints dropping into the upper
40s and lower 50s north of I-72. Front will continue to sag
southward today, eventually dropping south of the Ohio River by
late afternoon. As a result, cooler and less humid conditions can
be expected with high temps remaining in the 70s. Precip chances
will develop along/ahead of the front this afternoon, but will
remain south of the KILX CWA. The only potential fly in the
ointment will be a weak short-wave currently tracking out of
Colorado. As this feature approaches from the west, a few
showers/storms may spread into the far W/SW CWA this afternoon and
evening. While most models keep central Illinois completely dry
today and tonight, higher-res models such as the RAP and HRRR show
precip associated with the wave moving across central/southern
Iowa and approaching from the west this afternoon. Have therefore
included a slight chance POP along/southwest of a Rushville to
Jacksonville line this afternoon into tonight.
High pressure will build into the southern Great Lakes by the end
of the week, pushing the front even further south/southwest. With
dry N/NE flow around the high, sunny skies will be the rule on
both Friday and Saturday with temperatures in the 70s and low
relative humidity values.
LONG TERM...Sunday through Wednesday
As high slides off to the east, remnants of old frontal boundary
will return northward on Sunday. Models continue to produce some
QPF across the area as the warmer air returns: however, with only
meager forcing along a dissipating boundary and rising upper heights,
think this is overdone. Upper ridge will build in earnest across
the Midwest early next week, leading to temperatures climbing well
into the 80s. Big question will be how fast the ridge breaks down
as cut-off low currently over southern California works its way
eastward. GFS has been the slowest model with this process for the
past few runs and its 00z May 22 solution is no exception.
Meanwhile, ECMWF had previously been faster, but its latest run
has slowed down and now keeps wave west of Illinois until
Wednesday. Given high-amplitude upper ridge in place over the
Midwest, continue to favor a slower solution. Even though both the
GFS and ECMWF delay the arrival of the upper low until mid-week,
both produce QPF across the area on Monday and Tuesday. Given high
upper heights and lack of forcing, think little more than isolated
diurnal convection will fire on either of those two days. As such,
have kept the forecast dry until Wednesday when better forcing
arrives with the approaching upper low.
&&
.AVIATION...
ISSUED 655 AM CDT Thu May 22 2014
VFR conditions should prevail across the central IL airports
through 12Z/7 am Friday. Mid and high clouds to spread ese across
central IL during the day as ceilings lower to 7-12k ft. These
clouds will then scatter out from north to south during overnight
occurring near I-74 first. Isolated showers and thunderstorms
should stay sw of SPI this afteroon and evening. Thunderstorms
with MCS over nw MO, ne KS, se NE and sw IA and associated with a
short wave to track ese across northern MO and sw IL today and
evening along frontal boundary that has pushed south of I-70 early
this morning and will continue to stay south of central IL thru
tonight. NNW winds will be near 10 kts today and veer NNE tonight
and diminish to around 5 kts.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1040 AM EDT THU MAY 22 2014
.UPDATE...
ISSUED AT 1040 AM EDT THU MAY 22 2014
14Z SFC ANALYSIS SHOWS LOW PRESSURE HAS NOW MOVED TO OVER UPSTATE NEW
YORK WHILE ITS COLD FRONT STRETCHES SOUTHWEST THROUGH KENTUCKY.
EARLIER CONVECTION HAS PUSHED SOUTH OF EAST KENTUCKY...BUT ALSO LEFT
BEHIND AN OUTFLOW BOUNDARY THAT COULD BECOME SIGNIFICANT WITH DAYTIME
HEATING AND INSTABILITY. THE HRRR AND NAM12 KEEP MOST OF THE
REDEVELOPMENT SOUTH AND EAST OF OUR AREA LATER TODAY...BUT WITH THAT
BOUNDARY IN PLACE AND THE HISTORY OF THIS SYSTEM SEVERE WEATHER WILL
REMAIN A POSSIBILITY OVER FAR SOUTHERN PARTS OF THE CWA. FOR NOW...
THOUGH...IN THE WAKE OF THE EARLY MORNING STORMS A LULL WILL SET IN
FOR THE BULK OF EAST KENTUCKY. IN FACT...A PLEASANT DAY WILL BE HAD
FOR MOST WITH PARTLY SUNNY SKIES AND ANY STORMS STAYING TO THE SOUTH.
HOWEVER...THOSE SOUTHERN LOCALES...GENERALLY FROM THE HAL ROGERS
PARKWAY TO THE TENNESSEE BORDER...WILL HAVE TO BE ON THE LOOK OUT FOR
STORMS LATER THIS AFTERNOON AND SOME OF THESE COULD BE QUITE STRONG
WITH LARGE HAIL AND DAMAGING WIND GUSTS THE MAIN THREATS. HAVE
UPDATED THE GRIDS...ZONES...AND HWO TO REFLECT THESE EXPECTATIONS AND
ALSO INCORPORATED THE LATEST GUIDANCE...OBS...AND TRENDS INTO THE T
AND TD GRIDS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 345 AM EDT THU MAY 22 2014
MODELS HAVE BEEN HAVING A DIFFICULT TIME RESOLVING THE CLUSTERS OF
THUNDERSTORMS THAT HAVE BEEN PLAGUING THE AREA SINCE LATE WEDNESDAY
EVENING. THE FORECAST FROM 6Z THROUGH NOW WERE UPDATED MOSTLY USING
THE LATEST TRENDS OBSERVED IN RADAR AND SATELLITE IMAGERY. CURRENT
ACTIVITY HAS BEEN SHOWING A STEADY WEAKENING TREND OVER THE PAST HOUR
OR SO. ALL INDICATIONS ARE THAT ANY REMAINING THUNDERSTORMS WILL
PRODUCE MINIMAL WIND GUSTS AND ISOLATED INSTANCES OF LOCALLY HEAVY
RAINFALL THROUGH THE REMAINDER OF THE OVERNIGHT. MORE STORMS CONTINUE
TO FORM IN A PREFERRED AREA OF LIFT AND MOISTURE CONVERGENCE ACROSS
SOUTHERN INDIANA AND WILL LIKELY CONTINUE TO MOVE ACROSS CENTRAL AND
EASTERN KENTUCKY THROUGH EARLY THIS MORNING. THE MODELS ARE
INDICATING THAT THERE WILL BE BRIEF LULL IN ACTIVITY IN THE
MORNING...BEFORE THINGS RAMP BACK UP A BIT DURING THE AFTERNOON HOURS
AS A COLD FRONT SAGS SLOWLY SOUTHWARD ACROSS THE REGION OUT OF THE
OHIO VALLEY. THE MODEL CONSENSUS SAYS THAT THE LAST SHOWERS AND
STORMS WILL BE OUT OF THE AREA AROUND 5Z FRIDAY. THERE IS A SLIGHT
RISK THAT A FEW STORMS COULD APPROACH SEVERE LIMITS ALONG AND JUST
NORTH OF THE TENNESSEE BORDER TODAY...AS THIS WAS MENTIONED IN THE
HAZARDOUS WEATHER OUTLOOK EVEN THOUGH CONFIDENCE IS NOT HIGH THAT
THIS WILL OCCUR. STRONG WINDS AND LARGE HAIL WOULD BE THE PRIMARY
THREATS WITH ANY STORMS THAT REACH SEVERE STATUS. THE WEATHER FOR
THURSDAY NIGHT AND FRIDAY WILL DRY AND SLIGHTLY COOLER AS ANOTHER
RIDGE OF HIGH PRESSURE SETTLES OVER THE AREA.
TEMPERATURES TODAY WILL BE RUNNING ABOVE NORMAL ONCE AGAIN WITH
READINGS EXPECTED TO TOP OUT AROUND 80 DEGREES ACROSS THE AREA AS THE
AIR MASS BEHIND THE COLD FRONT QUICKLY MODIFIES. THE FRONT ITSELF IS
NOT ALL THAT WELL DEFINED SO THE AIR BEHIND IT WILL PROBABLY NOT COOL
THINGS OFF VERY MUCH ONCE THE FRONT HAS PASSED. IN SPITE OF THE
SLIGHTLY COOLER AIR MASS...TEMPERATURES ON FRIDAY SHOULD STILL BE
ABLE TO TOP OUT IN THE UPPER 70S ACROSS THE BOARD.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT THU MAY 22 2014
THE MODELS IN THE LONG TERM START OUT IN VERY GOOD AGREEMENT WITH A
CUT OFF UPPER LOW OVER ARIZONA...UPPER RIDGING OVER THE PLAINS AND
AN UPPER TROUGH OVER THE EAST COAST. AT THE SURFACE HIGH PRESSURE IS
DOMINATING THE AREA. THE UPPER LOW OVER ARIZONA TRACKS SLOWLY TO THE
NORTHEAST OVER TIME AS THE RIDGE AXIS MOVE SLOWLY TO THE EAST AND
WILL BE LOCATED OVER THE MISSISSIPPI VALLEY BY SATURDAY EVENING. BY
TUESDAY AFTERNOON...SOME AFTERNOON AIR MASS THUNDERSTORMS MAY BE
POSSIBLE AS THE UPPER LOW APPROACHES THE AREA. BY THIS TIME THE
MODELS ARE STARTING TO DIVERGE AND CONFIDENCE PLUMMETS. ISOLATED TO
SCATTERED THUNDERSTORMS WILL BE POSSIBLE THROUGH THE END OF THE
PERIOD. FOR TEMPERATURES...STAYED CLOSE TO THE MODEL BLEND...HOWEVER
NUDGED THEM TOWARD THE RAW ECMWF AND MADE CORRECTIONS DUE TO
TERRAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 746 AM EDT THU MAY 22 2014
THE STORMS ARE IN THE PROCESS OF MOVING OUT OF THE AREA. MOSTLY VFR
CONDITIONS EXIST ACROSS THE AREA WITH THE EXCEPTION OF NEAR THE STORMS
AND IN SOME MID SLOPE LOCATIONS. EXPECT SOME THUNDERSTORMS TO FORM
THIS AFTERNOON...HOWEVER NOT WITH ENOUGH CONFIDENCE TO PUT IT IN THE
FORECAST. EXPECTING SOME MVFR FOG NEAR DAWN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...JJ
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1109 AM EDT THU MAY 22 2014
.SYNOPSIS...
A COLD FRONT WILL PASS THROUGH THE REGION LATE THIS AFTERNOON. AN UPPER
LEVEL DISTURBANCE WILL PIVOT ACROSS THE AREA FRIDAY...FOLLOWED BY
BUILDING HIGH PRESSURE FOR THE WEEKEND.
&&
.NEAR TERM /TODAY/...
SFC ANLYS SHOWED LOW PRES OVR LAKE ONTARIO W/ A WARM FNT
STRETCHING S OF NJ AND A CD FNT XTNDG ACROSS OH. MID ATLC HAS
ALREADY WARMED INTO THE M70S...GOING UP INTO THE M80S. SKIES HV
STARTED THE DAY CLR WHICH WL ALLOW FOR GOOD HTG.
SPC HAS AREA E OF I-95 IN A SLT RISK FOR WIND/HAIL. THIS IS WHAT
THE SREF SVR PARAMETES ARE IMPLYING...ARND 00Z. HOWEVER THIS IN
NOT BEING SEEN IN THE HRRR HRLY PLOT. LOOKING AT THE SNDG THIS
SCENARIO COULD BEST BE DESCRIBED AS "MDTLY HIGH CAPE/MINIMAL
SHEAR" - AFTN HTG COULD PRODUCE UP TO 1500 JOULES..BUT UPR LVL
WIND FIELD LOOKS TO BE ALMOST SINGULARLY WNW. HENCE GUSTY
WINDS/HAIL ARE WHAT WOULD BE CONSIDERED THE BEST THREAT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
FNT SHUD CLR AREA BY ELY EVNG...W/ CAA/LWR DEWPTS/CLRG SKIES
ARRIVING THRU THE NGT. HWVR...PTTN ALOFT WL STILL BE CHARACTERIZED
BY BROAD TROFFING ACRS THE NERN CONUS. A S/WV W/IN THIS TROF WL BE
PIVOTING ACRS AREA FRI. THAT WL SUPPORT ADDTL CLDS AND 20-30 POPS
DURING THE DAY. ATM WL BE STBL BY THIS PT...SO ANY PCPN WUD BE JUST
SHRA.
A BLEND OF MOS GNLY ACCEPTED...XCPT MAV MAXT FRI SEEMED A BIT TOO
WARM.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SKIES WILL CLEAR THROUGH THE EARLY MORNING HOURS SAT AND MOST OF THE
AREA WILL BE MOSTLY SUNNY FOR SUNRISE SAT. THE EXCEPTION IS ALONG
THE BAY...WHERE LOW END RAIN CHANCES WERE KEPT THROUGH THE DAY AS
THE SURFACE LOW DEEPENS AS IT MOVES AWAY FROM THE MID ATLANTIC
COAST. ANY LINGERING PRECIP THAT DOES FORM SHOULD BE OUT OF THE AREA
BY SATURDAY EVENING. HIGH TEMPS WILL GENERALLY BE IN THE MID 70S FRI
AND SAT WITH LOWS AROUND 50 BOTH NIGHTS.
SATURDAY NIGHT INTO SUNDAY BECOME QUIET WEATHER-WISE WITH
WEAKENING NORTHWEST FLOW ALOFT AND SURFACE HIGH PRESSURE BUILDING
ACROSS THE MID-ATLANTIC. RISING HEIGHTS SUNDAY INTO EARLY NEXT
WEEK WILL BRING A GOOD WARMING TREND AS FAIRLY BROAD UPPER RIDGE
PUSHES EAST AHEAD OF A PROGRESSIVE PACIFIC LOW. HIGH PRESSURE IN
PLACE SUNDAY /AND SLOW TO MOVE OUT/ WILL LIMIT MOISTURE RETURN
INTO MONDAY. STRONGER SOUTHWEST FLOW AND INCREASING MOISTURE WILL
BRING THE CHANCE OF STORMS BACK INTO THE FORECAST TUESDAY ON THE
NORTHERN EDGE OF A BUILDING THERMAL RIDGE.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR CONDS MAJORITY OF TDA. LATE AFTN/ERLY EVE TSTMS PSBL. GUSTY NW
WINDS ERLY THIS EVE.
WL HV AN UPR LVL DISTURBANCE ROTATING THRU FRI. VFR CIGS BKN050...
MAINLY DRING THE AFTN-ELY EVE. WNDS WL PICK UP AGN AS WELL...
10-15 KT W/ A FEW G20KT.
VFR UNDER HIPRES SAT-MON.
&&
.MARINE...
WINDS IN THE 10-15 KT RANGE ATTM BUT ARE XPCTD TO INCRS THIS AFTN
AHD OF AN APRCHG CD FNT. SCA IN EFFECT THIS AFTN. TSTMS ARE PSBL
LATE THIS AFTN/ERLY EVE.
MIXING WL BE MAINTAINED INTO THE NGT...SPCLY ON THE OPEN WATERS...
AND WL BE ENHANCED BY A S/WV FRI. SCA FOR MOST OF THE WATERS /XPCT
FOR MID-UPR PTMC/ CONTS TNGT. WL ADD SCA FOR ALL WATERS FRI.
HIGH PRESSURE WILL BUILD INTO THE REGION LATE IN THE WEEKEND AND
EARLY NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM EDT
FRIDAY FOR ANZ530>534-537>541-543.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM EDT
THIS EVENING FOR ANZ535-536-542.
SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EDT FRIDAY FOR ANZ535-
536-542.
&&
$$
UPDATE...WOODY!
PRVS...HTS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
636 AM CDT THU MAY 22 2014
.UPDATE...
ISSUED AT 459 AM CDT THU MAY 22 2014
ALREADY SENDING AN UPDATE TO ACCOUNT FOR THE LIFT GENERATING NEW
SHWRS BETWEEN MCK-IML-AKO. THE PUB/GLD RADARS SHOW 25-30 KTS FROM
THE SW AT 5K FT AGL. THE NAM/GFS DO INDICATE ISENTROPIC LIFT WHERE
THESE SHWRS ARE DEVELOPING. NOT SURE HOW MUCH OF THIS WILL HEAD E
INTO THE FCST AREA. SO POPS HAVE BEEN INCREASED THIS MORNING AND
ANTICIPATE FURTHER SHORT-TERM ADJUSTMENTS AS THE MORNING PROCEEDS.
IRONICALLY I USED THE 06Z NAM AS A GUIDE. IF THE NAM TURNS OUT
CORRECT...MAJOR FCST ADJUSTMENTS WILL BE NEEDED LATER THIS
MORNING. WE HAVE NOTED SEVERAL MODELS CAP HIGH TEMPS IN THE UPPER
60S OVER MUCH OF S-CNTRL NEB.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT THU MAY 22 2014
...A DIFFICULT FCST THRU TONIGHT WITH BELOW AVERAGE CONFIDENCE
DUE TO POOR MODEL HANDLING OF THE PLETHORA OF MESOSCALE ASPECTS...
ALOFT: THE LONGWAVES ARE ESSENTIALLY STAGNANT OVER THE CONUS. A
588 SUB-TROPICAL HIGH WAS OVER THE GULF COAST STATES AND WILL
REMAIN THERE THRU TONIGHT. ITS RIDGE AXIS WILL CONT TO EXTEND NW
ACROSS THE CNTRL PLAINS TO MT. THE CUT-OFF LOW OVER NV/CA WILL
MEANDER FURTHER S INTO AZ TONIGHT.
SURFACE: A COOL FRONT REMAINS STALLED W-E ACROSS KS AND WILL
REMAIN IN PLACE THRU AT LEAST TONIGHT. OVERNIGHT TSTM ACTIVITY
WILL STRENGTHEN THE FRONT TODAY. NRN PLAINS HIGH PRES WILL DRIFT
INTO THE WRN GREAT LAKES.
REST OF THIS MORNING: TSTM CLUSTERS WILL CONT EXITING INTO ERN
NEB/KS. CANT COMPLETELY RULE OUT A COUPLE MORE ISOLATED SHWRS/
TSTMS FROM DEVELOPING...BUT THE OVERALL TREND SHOULD BE DRIER.
THIS AGREES WITH THE 03Z HRRR AND 00Z HI-RES WRF RUNS.
QUIET SYNOPTIC REGIMES SUCH AS THIS CREATE MAJOR HEADACHES FOR
FCSTRS. A LOT OF IT COMES DOWN TO INTUITION AS MECHANISMS TO
TRIGGER TSTMS ARE SUBTLE. BUST POTENTIAL IS AT EVERY CORNER FOR
TEMPS/SKY/PRECIP.
TODAY: MOSTLY CLOUDY THIS MORNING WITH LOTS OF CLOUD DEBRIS
AROUND ...BUT IR SATELLITE SHOWS A CLEARING LINE ADVANCING UP FROM
THE TX PANHANDLE. THE TIME-OF-ARRIVAL TOOL BRINGS IT TO OUR SW
COUNTIES BY 830 AM AND TO OUR NE COUNTIES BY 130 PM. SO SKIES
SHOULD TURN PARTLY CLOUDY IF NOT MOSTLY SUNNY THIS AFTERNOON. THIS
BARRING ANY STRATUS THAT MIGHT FORM IN THE PREDAWN HOURS.
BEFORE THE TSTMS FIRED YESTERDAY AFTERNOON...WATER VAPOR IMAGERY
SHOWED WHAT APPEARED TO BE A SHORTWAVE TROF LIFTING FROM NM INTO
THE CNTRL PLAINS. THIS TROF SHOULD ROUND THE RIDGE WITH SUBSIDENCE
TO FOLLOW TODAY. THIS IS PROBABLY WHAT WE ARE SEEING WITH THAT
CLEARING LINE IN SATELLITE.
THE 00Z/06Z NAM CONVECTIVE SCHEMES RE-FIRE TSTMS BY MIDDAY
TODAY...BASICALLY AS SOON AS THE CONVECTIVE TEMP IS REACHED. I
JUST CANNOT SEE THAT HAPPENING IN THE WAKE OF THE DEPARTING TROF.
WOULD EXPECT SOME SUBSIDENCE INVERSION TO RESULT IN AT LEAST A
MODEST CAP. SO THE FCST IS DRY UNTIL 5PM WHEN SLIGHT CHANCE POPS
WERE BROUGHT INTO OUR N-CNTRL KS COUNTIES. HAVE FOLLOWED THE 00Z
WRF RUNS FROM THE NAM... THE NSSL WRF AND THE 07Z/08Z 13 KM RAP
WHICH DO NOT REFIRE CONVECTION.
OTHER MESOSCALE DETAILS: WITH THE HIGH DRIFTING FURTHER E...THE
E-W ORIENTED BAND OF RICH 850 MB MOISTURE ALONG THE FRONT WILL
BEGIN CIRCULATING NW...LIFTING INTO NEB. HOWEVER...SURFACE
DEWPOINTS UPSTREAM OVER IA WERE STILL IN THE MID 40S. SO WHILE IN
SITU DEWPOINTS HAVE RISEN OVERNIGHT...VERY LOW-LEVEL DRY AIR
ADVECTION WILL BE OCCURRING.
ISOLATED TSTMS COULD FIRE ALONG THE CONVECTIVELY REINFORCED WARM
FRONT OVER KS. THIS ACTIVITY COULD LIFT INTO OUR N-CNTRL KS
COUNTIES AND THIS IS WHAT IS FCST BY THE NON-HYDROSTATIC MODELS.
NAM PV IMAGES SHOW A SUBTLE SHORTWAVE TROF EMBEDDED IN THE DRY
SLOT CURRENTLY OVER AZ. MOVEMENT IS NNE AND IT IS FCST TO LIFT
ACROSS NM AND INTO CO TONIGHT. THIS SHOULD TRIGGER THE TSTMS LATE
THIS AFTERNOON AND EVENING OVER THE HIGH PLAINS. WE THEN
ANTICIPATE THIS ACTIVITY TO THREATEN OR MOVE INTO THE FCST AREA
FROM THE SW AGAIN TONIGHT. NO GUARANTEES ON THIS THOUGH. SEVERAL
NON-HYDROSTATIC MODELS KEEP THE FCST AREA DRY. SO POPS WERE KEPT
LOW.
TONIGHT: INCREASING CLOUDS WITH A CHANCE OF SHWRS/TSTMS. GREATEST
CHANCE S AND W OF THE TRI-CITIES. EFFECTIVE SHEAR WILL BE AROUND
30 KTS. WHILE AN ISOLATED SEVERE TSTM IS POSSIBLE OVER N-CNTRL KS
BEFORE MIDNIGHT...IT IS LARGELY BASED ON "IF" TSTMS OCCUR AT ALL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 417 AM CDT THU MAY 22 2014
GUIDANCE SUGGESTS A CLOSED UPPER TROPOSPHERIC LOW WILL EXIST OVER
THE SOUTHWESTERN CONUS AT 12Z FRIDAY. THIS CLOSED LOW IS THEN
EXPECTED TO DRIFT TO THE NORTHEAST AND WEAKEN...EVENTUALLY MOVING
OVER THE CENTRAL PLAINS AS AN OPEN WAVE BY EARLY NEXT WEEK. AT THE
SURFACE SOUTH OR SOUTHEASTERLY FLOW IS EXPECTED TO PERSIST ACROSS
THE AREA THROUGH MUCH OF THE LONG TERM FORECAST PERIOD.
UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE SOUTHWESTERN
UPPER TROPOSPHERIC CLOSED LOW...ALONG WITH MULTIPLE SUBTLE UPPER
TROPOSPHERIC PERTURBATIONS EJECTING FROM THE SOUTHWESTERN
CONUS...WILL CONTINUE TO PROMOTE CHANCES FOR PRECIPITATION ACROSS
THE CWA MOST EVERY DAY DURING THE LONG TERM FORECAST PERIOD. WENT
AHEAD AND TOOK AN EVEN BLEND OF NAM...OPERATIONAL GFS...EC...SREF-
MEAN AND WPC GUIDANCE TO DERIVE QPF GRIDS BOTH FRIDAY AND
SATURDAY...AND THEN DERIVED THE POP GRIDS FROM THESE QPF GRIDS.
AFTER ALL WAS SAID AND DONE...VERY LITTLE CHANGE WAS MADE TO THE
GOING FORECAST. OVERALL...30-60% POPS REMAIN INTACT FOR THE MOST
PART ACROSS THE CWA FRIDAY THROUGH SATURDAY NIGHT. SUNDAY AND
BEYOND...ALLBLEND PROVIDED 20-60% POPS TO VARIOUS PORTIONS OF THE
CWA DURING THE LONG TERM FORECAST PERIOD. THESE POPS WERE LEFT
UNCHANGED FOR THE MOST PART.
CONTINUED SOUTH/SOUTHEASTERLY LOWER TROPOSPHERIC FLOW SHOULD KEEP
INCREASED VALUES OF LOWER TROPOSPHERIC MOISTURE INTACT ACROSS THE
AREA THROUGH EARLY TO MID NEXT WEEK...THUS RESULTING IN 1000-
3000J/KG OF POTENTIAL INSTABILITY EACH AFTERNOON AND EVENING.
ALTHOUGH DEEP-LAYER BULK SHEAR WONT BE ANYTHING TO GET EXCITED
ABOUT...THE MAGNITUDE OF POTENTIAL INSTABILITY ALONE COULD BE
ENOUGH TO PROMOTE STRONG UPDRAFT PRODUCTION CAPABLE OF RESPECTABLE
HAIL SIZE AND PERHAPS DOWN-BURST WIND. THE INHERITED HWO ALREADY
HAD A MENTION OF STRONG STORMS EACH AFTERNOON AND EVENING AND AT
THIS TIME THERE REALLY IS NO REASON TO CHANGE THIS. AS A
RESULT...WENT AHEAD AND MENTIONED THE POSSIBILITY OF STRONG
THUNDERSTORMS EACH AFTERNOON AND EVENING FRIDAY THROUGH NEXT
WEDNESDAY.
LITTLE IF ANY CHANGE IN THE LOWER TROPOSPHERIC AIR MASS WILL
PRESENT SIMILAR TEMPERATURE READINGS FROM DAY TO DAY DURING THE
LONG TERM FORECAST PERIOD...WITH HIGHS GENERALLY IN THE 70S AND
80S AND LOWS IN THE 50S AND 60S CURRENTLY FORECAST.
&&
.AVIATION...(FOR THE 12Z GRI TAF THROUGH 12Z FRIDAY MORNING)
ISSUED AT 635 AM CDT THU MAY 22 2014
TODAY: VFR. RAIN SHOULD BE DONE FOR THE DAY. MULTI-LAYERED VFR
CEILINGS SHOULD CLEAR OUT WITH SCT CU DEVELOPING 16-18Z. E WINDS
WILL AVERAGE 10 KTS. CONFIDENCE: MEDIUM
TONIGHT: VFR THRU 06Z. TSTMS WILL ERUPT WELL TO THE W AND S OF THE
TERMINAL WHICH WILL SEND HIGH-LEVEL VFR CEILINGS BACK OVER GRI.
00Z AND 06Z GFS MOS AND THE BETTER-PERFORMING GFS LAMP GUIDANCE
BOTH INDICATE FLIGHT CONDITIONS WILL DECAY AFTER 06Z IN IFR
STRATUS AND MVFR FOG. FOR NOW WE HAVE HINTED AT THIS IN THE TAF.
WOULD LIKE TO SEE HOW FCST GUIDANCE EVOLVES THRU THE DAY BEFORE
BECOMING MORE PESSIMISTIC. A BAND OF RICH LOW-LEVEL MOISTURE
/CURRENTLY OVER KS/ WILL SPREAD N INTO NEB TONIGHT. THIS MAY BE
WHAT THE MODELS ARE KEYING ON. E WINDS WILL BE UNDER 10 KTS.
CONFIDENCE: MEDIUM BEFORE 06Z. LOW AFTER 06Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
839 AM PDT THU MAY 22 2014
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL CIRCULATE OVER SOUTHERN
NEVADA AND SURROUNDING AREAS THROUGH FRIDAY PRODUCING ISOLATED TO
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. THE SYSTEM WILL
FINALLY MOVE AWAY TO THE EAST SATURDAY...WITH RAIN CHANCES
DIMINISHING AND TEMPERATURES QUICKLY WARMING OVER THE HOLIDAY
WEEKEND.
&&
.UPDATE...A FEW LIGHT SHOWERS ARE ONGOING OVER INYO AND SAN
BERNARDINO COUNTY THIS MORNING. MADE SOME TWEAKS TO THE
SKY/POP/QPF/WX GRIDS THROUGH THIS EVENING BASED OFF THE LATEST
RADAR/SATELLITE IMAGERY AND HIGH-RES MODEL GUIDANCE. I EXPANDED
POPS A BIT FURTHER EAST IN SAN BERNARDINO COUNTY...AND REDUCED THEM
OVER CENTRAL NYE. IN GENERAL THERE IS AT LEAST A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS EAST OF US 95 TODAY...WITH THE
BEST CHANCES OVER THE TERRAIN OF INYO AND SAN BERNARDINO COUNTIES.
WITH LIMITED MOISTURE TO WORK WITH GUSTY WINDS TO 30-40 MPH WILL BE
THE PRIMARY THREAT WITH ANY STORMS TODAY. THERE WILL BE THE
POTENTIAL FOR SOME GUSTS TO AROUND 50 MPH IN SAN BERNARDINO COUNTY.
GENERAL STORM MOTION WILL BE WEST AT 5-10 MPH.
&&
.PREV UPDATE...
ISSUED 632 AM PDT THU MAY 22 2014
.UPDATE...NEEDED TO INCREASE POPS AND CLOUDS ACROSS WESTERN INYO
COUNTY FOR THE REST OF THIS MORNING. NEW TEXT PRODUCTS SENT ON THE
HALF HOUR. NO OTHER CHANGES.
.PREV DISCUSSION...
300 AM PDT THU MAY 22 2014
.SHORT TERM...THROUGH SATURDAY NIGHT...WATER VAPOR SHOWS TWO
DISTINCT WAVES CIRCULATING WITHIN THE TROUGH WHICH HAS CUTOFF FROM
THE WESTERLIES OVER NEVADA/CALIFORNIA. FIRST SHORTWAVE OVER WEST
CENTRAL NEVADA WILL BE MOVING SOUTHWEST THROUGH MONO/NORTHWEST INYO
COUNTIES THIS MORNING. THE LATEST HRRR SPREADS LIGHT SHOWERS SOUTH
THROUGH THE EASTERN SIERRA SLOPES OF INYO AS WELL AS THE NORTHERN
OWEN VALLEY THROUGH 8 OR 9 AM THIS MORNING. SECOND WAVE WAS ALONG
THE SOUTHERN CALIFORNIA COAST HELPING DEEPEN THE MARINE LAYER.
TODAY, MODELS REMAIN IN GOOD AGREEMENT INDICATING MOISTURE AND
INSTABILITY WILL STAY IN THE WESTERN HALF OF THE FORECAST AREA OR
WEST OF LAS VEGAS. AS TROUGH/UPPER LOW SLOWLY SHIFTS FROM SOUTHERN
CALIFORNIA EAST INTO ARIZONA THE PROBABILITIES FOR SHOWERS WILL
FINALLY INCREASE FOR THE HIGHER TERRAIN OF MOHAVE/LINCOLN AND
EASTERN CLARK COUNTIES FRIDAY AND SATURDAY. TO KICK OFF THE HOLIDAY
WEEKEND ON FRIDAY AND SATURDAY TEMPERATURES WILL BE NEAR TO SLIGHTLY
ABOVE NORMAL. ONLY WIND CONCERN OVER THE COMING DAYS WILL BE FROM
THUNDERSTORMS WHERE GUSTS OF 30 TO 40 MPH ARE POSSIBLE.
.LONG TERM...SUNDAY THROUGH THURSDAY NIGHT.
THE MAIN TREND IN THE UPCOMING WEEK APPEARS TO BE A COOLING TREND,
THOUGH HOW BIG OF A COOLING TREND REMAINS UP FOR DEBATE. A
POSITIVELY TILTED MID/UPPER LEVEL RIDGE IS SHOWN TO EXTEND INTO
CALIFORNIA AND NEVADA ON SUNDAY INTO MEMORIAL DAY AHEAD OF AN
INCOMING MID/UPPER LEVEL TROUGH THAT DIGS SOUTH ACROSS THE PAC NW
INTO NORCAL. THE 00Z OPERATIONAL GFS AND TO A LESSER EXTENT THE
SLIGHTLY DRIER ECMWF BOTH SHOW ENOUGH INSTABILITY, CAPE AND
MID-LEVEL MOISTURE ON SUNDAY AFTERNOON OVER THE SOUTHERN SIERRA AND
WHITE MOUNTAINS THAT WE SHOULD SEE AT LEAST SOME CUMULUS BUILD-UPS.
HOWEVER, A FEW SHOWERS OR EVEN A THUNDERSTORM MAY MATERIALIZE AND
POPS WERE INCREASED TO THE 10-15 PERCENT RANGE OVER THESE AREAS FOR
SUNDAY AFTERNOON AND EVENING. BY MONDAY, THINGS LOOK MORE STABLE AS
THE TROUGH APPROACHES, AT THUS THE FORECAST GRIDS ONLY REFLECT
DEVELOPMENT OF CUMULUS IN THE AFTERNOON OVER THESE AREAS. AHEAD OF
THE INCOMING TROUGH, INCREASING SOUTHWEST FLOW WILL ALLOW FOR GOOD
MIXING AND THUS HIGH TEMPS WERE BOOSTED A COUPLE OF DEGREES OVER THE
PREVIOUS FORECAST, ESPECIALLY FOR MEMORIAL DAY BASED ON FORECAST
SOUNDINGS AND STATISTICAL GUIDANCE.
AS WE MOVE INTO THE MIDDLE OF NEXT WEEK, THE TROUGH ALOFT IS
FORECAST TO REMAIN INTO NORCAL WITH A SOUTHWEST FLOW SETTING UP
ACROSS OUR ENTIRE AREA. AS HEIGHTS SLOWLY LOWER AND TEMPS ALOFT
COOL, TEMPS AT THE SURFACE WILL ALSO GRADUALLY DROP A FEW DEGREES
EACH DAY FROM TUESDAY ONWARD, HOWEVER, THEY SHOULD STILL REMAIN AT
LEAST A FEW DEGREES ABOVE NORMAL. THE MOST NOTICEABLE DROP SHOULD BE
IN THE WESTERN CWFA WHERE IT IS POSSIBLE THE SYNOPTIC COOLING ALSO
GETS A LITTLE BOOST FROM ANY MARINE INFLUENCE THAT CAN TRICKLE
THROUGH THE COASTAL RANGE PASSES. OTHERWISE EXPECT DRY CONDITIONS
WITH A FEW CLOUDS AROUND AT TIMES.
&&
.AVIATION...FOR MCCARRAN...WIND SPEEDS UNDER 8 KTS THIS MORNING
WITH AN EASTERLY WIND COMPONENT DEVELOPING THIS AFTERNOON. CLOUDS
DEVELOPING THROUGHOUT THE DAY WITH BASES 10-12 KFT WITH LIGHT
SHOWERS POSSIBLE OVER THE SPRING MOUNTAINS AND SHEEP RANGE THIS
AFTERNOON AND EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...A LOW PRESSURE
SYSTEM WILL BE OVER SOUTHERN CALIFORNIA TODAY. ISOLATED TO SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS CAN BE EXPECTED IN AREAS TO THE
WEST OF LAS VEGAS. CLOUD BASES WILL GENERALLY BE AROUND 8-10
KFT MSL AND WILL LEAD TO PARTIAL MOUNTAIN OBSCURATION OVER THE
SOUTHERN SIERRA.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
UPDATE...WOLCOTT
PREV DISCUSSION...PIERCE/STACHELSKI
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
632 AM PDT THU MAY 22 2014
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL CIRCULATE OVER SOUTHERN
NEVADA AND SURROUNDING AREAS THROUGH FRIDAY PRODUCING ISOLATED TO
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. THE SYSTEM WILL
FINALLY MOVE AWAY TO THE EAST SATURDAY...WITH RAIN CHANCES
DIMINISHING AND TEMPERATURES QUICKLY WARMING OVER THE HOLIDAY
WEEKEND.
&&
.UPDATE...NEEDED TO INCREASE POPS AND CLOUDS ACROSS WESTERN INYO
COUNTY FOR THE REST OF THIS MORNING. NEW TEXT PRODUCTS SENT ON THE
HALF HOUR. NO OTHER CHANGES.
.PREV DISCUSSION...
300 AM PDT THU MAY 22 2014
.SHORT TERM...THROUGH SATURDAY NIGHT...WATER VAPOR SHOWS TWO
DISTINCT WAVES CIRCULATING WITHIN THE TROUGH WHICH HAS CUTOFF FROM
THE WESTERLIES OVER NEVADA/CALIFORNIA. FIRST SHORTWAVE OVER WEST
CENTRAL NEVADA WILL BE MOVING SOUTHWEST THROUGH MONO/NORTHWEST INYO
COUNTIES THIS MORNING. THE LATEST HRRR SPREADS LIGHT SHOWERS SOUTH
THROUGH THE EASTERN SIERRA SLOPES OF INYO AS WELL AS THE NORTHERN
OWEN VALLEY THROUGH 8 OR 9 AM THIS MORNING. SECOND WAVE WAS ALONG
THE SOUTHERN CALIFORNIA COAST HELPING DEEPEN THE MARINE LAYER.
TODAY, MODELS REMAIN IN GOOD AGREEMENT INDICATING MOISTURE AND
INSTABILITY WILL STAY IN THE WESTERN HALF OF THE FORECAST AREA OR
WEST OF LAS VEGAS. AS TROUGH/UPPER LOW SLOWLY SHIFTS FROM SOUTHERN
CALIFORNIA EAST INTO ARIZONA THE PROBABILITIES FOR SHOWERS WILL
FINALLY INCREASE FOR THE HIGHER TERRAIN OF MOHAVE/LINCOLN AND
EASTERN CLARK COUNTIES FRIDAY AND SATURDAY. TO KICK OFF THE HOLIDAY
WEEKEND ON FRIDAY AND SATURDAY TEMPERATURES WILL BE NEAR TO SLIGHTLY
ABOVE NORMAL. ONLY WIND CONCERN OVER THE COMING DAYS WILL BE FROM
THUNDERSTORMS WHERE GUSTS OF 30 TO 40 MPH ARE POSSIBLE.
.LONG TERM...SUNDAY THROUGH THURSDAY NIGHT.
THE MAIN TREND IN THE UPCOMING WEEK APPEARS TO BE A COOLING TREND,
THOUGH HOW BIG OF A COOLING TREND REMAINS UP FOR DEBATE. A
POSITIVELY TILTED MID/UPPER LEVEL RIDGE IS SHOWN TO EXTEND INTO
CALIFORNIA AND NEVADA ON SUNDAY INTO MEMORIAL DAY AHEAD OF AN
INCOMING MID/UPPER LEVEL TROUGH THAT DIGS SOUTH ACROSS THE PAC NW
INTO NORCAL. THE 00Z OPERATIONAL GFS AND TO A LESSER EXTENT THE
SLIGHTLY DRIER ECMWF BOTH SHOW ENOUGH INSTABILITY, CAPE AND
MID-LEVEL MOISTURE ON SUNDAY AFTERNOON OVER THE SOUTHERN SIERRA AND
WHITE MOUNTAINS THAT WE SHOULD SEE AT LEAST SOME CUMULUS BUILD-UPS.
HOWEVER, A FEW SHOWERS OR EVEN A THUNDERSTORM MAY MATERIALIZE AND
POPS WERE INCREASED TO THE 10-15 PERCENT RANGE OVER THESE AREAS FOR
SUNDAY AFTERNOON AND EVENING. BY MONDAY, THINGS LOOK MORE STABLE AS
THE TROUGH APPROACHES, AT THUS THE FORECAST GRIDS ONLY REFLECT
DEVELOPMENT OF CUMULUS IN THE AFTERNOON OVER THESE AREAS. AHEAD OF
THE INCOMING TROUGH, INCREASING SOUTHWEST FLOW WILL ALLOW FOR GOOD
MIXING AND THUS HIGH TEMPS WERE BOOSTED A COUPLE OF DEGREES OVER THE
PREVIOUS FORECAST, ESPECIALLY FOR MEMORIAL DAY BASED ON FORECAST
SOUNDINGS AND STATISTICAL GUIDANCE.
AS WE MOVE INTO THE MIDDLE OF NEXT WEEK, THE TROUGH ALOFT IS
FORECAST TO REMAIN INTO NORCAL WITH A SOUTHWEST FLOW SETTING UP
ACROSS OUR ENTIRE AREA. AS HEIGHTS SLOWLY LOWER AND TEMPS ALOFT
COOL, TEMPS AT THE SURFACE WILL ALSO GRADUALLY DROP A FEW DEGREES
EACH DAY FROM TUESDAY ONWARD, HOWEVER, THEY SHOULD STILL REMAIN AT
LEAST A FEW DEGREES ABOVE NORMAL. THE MOST NOTICEABLE DROP SHOULD BE
IN THE WESTERN CWFA WHERE IT IS POSSIBLE THE SYNOPTIC COOLING ALSO
GETS A LITTLE BOOST FROM ANY MARINE INFLUENCE THAT CAN TRICKLE
THROUGH THE COASTAL RANGE PASSES. OTHERWISE EXPECT DRY CONDITIONS
WITH A FEW CLOUDS AROUND AT TIMES.
&&
.AVIATION...FOR MCCARRAN...WIND SPEEDS UNDER 8 KTS THIS MORNING WITH
AN EASTERLY WIND COMPONENT DEVELOPING THIS AFTERNOON. CLOUDS
DEVELOPING THROUGHOUT THE DAY WITH BASES 10-12 KFT WITH LIGHT
SHOWERS POSSIBLE OVER THE SPRING MOUNTAINS AND SHEEP RANGE
THIS AFTERNOON AND EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...A LOW PRESSURE
SYSTEM WILL BE OVER SOUTHERN CALIFORNIA TODAY. ISOLATED TO SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS CAN BE EXPECTED IN AREAS TO THE
WEST OF LAS VEGAS. CLOUD BASES WILL GENERALLY BE AROUND 8-10
KFT MSL AND WILL LEAD TO PARTIAL MOUNTAIN OBSCURATION OVER THE
SOUTHERN SIERRA.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
PIERCE/STACHELSKI
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
300 AM PDT THU MAY 22 2014
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL CIRCULATE OVER SOUTHERN
NEVADA AND SURROUNDING AREAS THROUGH FRIDAY PRODUCING ISOLATED TO
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. THE SYSTEM WILL
FINALLY MOVE AWAY TO THE EAST SATURDAY...WITH RAIN CHANCES
DIMINISHING AND TEMPERATURES QUICKLY WARMING OVER THE HOLIDAY
WEEKEND.
&&
.SHORT TERM...THROUGH SATURDAY NIGHT...WATER VAPOR SHOWS TWO
DISTINCT WAVES CIRCULATING WITHIN THE TROUGH WHICH HAS CUTOFF FROM
THE WESTERLIES OVER NEVADA/CALIFORNIA. FIRST SHORTWAVE OVER WEST
CENTRAL NEVADA WILL BE MOVING SOUTHWEST THROUGH MONO/NORTHWEST INYO
COUNTIES THIS MORNING. THE LATEST HRRR SPREADS LIGHT SHOWERS SOUTH
THROUGH THE EASTERN SIERRA SLOPES OF INYO AS WELL AS THE NORTHERN
OWEN VALLEY THROUGH 8 OR 9 AM THIS MORNING. SECOND WAVE WAS ALONG
THE SOUTHERN CALIFORNIA COAST HELPING DEEPEN THE MARINE LAYER.
TODAY, MODELS REMAIN IN GOOD AGREEMENT INDICATING MOISTURE AND
INSTABILITY WILL STAY IN THE WESTERN HALF OF THE FORECAST AREA OR
WEST OF LAS VEGAS. AS TROUGH/UPPER LOW SLOWLY SHIFTS FROM SOUTHERN
CALIFORNIA EAST INTO ARIZONA THE PROBABILITIES FOR SHOWERS WILL
FINALLY INCREASE FOR THE HIGHER TERRAIN OF MOHAVE/LINCOLN AND
EASTERN CLARK COUNTIES FRIDAY AND SATURDAY. TO KICK OFF THE HOLIDAY
WEEKEND ON FRIDAY AND SATURDAY TEMPERATURES WILL BE NEAR TO SLIGHTLY
ABOVE NORMAL. ONLY WIND CONCERN OVER THE COMING DAYS WILL BE FROM
THUNDERSTORMS WHERE GUSTS OF 30 TO 40 MPH ARE POSSIBLE.
.LONG TERM...SUNDAY THROUGH THURSDAY NIGHT.
THE MAIN TREND IN THE UPCOMING WEEK APPEARS TO BE A COOLING TREND,
THOUGH HOW BIG OF A COOLING TREND REMAINS UP FOR DEBATE. A
POSITIVELY TILTED MID/UPPER LEVEL RIDGE IS SHOWN TO EXTEND INTO
CALIFORNIA AND NEVADA ON SUNDAY INTO MEMORIAL DAY AHEAD OF AN
INCOMING MID/UPPER LEVEL TROUGH THAT DIGS SOUTH ACROSS THE PAC NW
INTO NORCAL. THE 00Z OPERATIONAL GFS AND TO A LESSER EXTENT THE
SLIGHTLY DRIER ECMWF BOTH SHOW ENOUGH INSTABILITY, CAPE AND
MID-LEVEL MOISTURE ON SUNDAY AFTERNOON OVER THE SOUTHERN SIERRA AND
WHITE MOUNTAINS THAT WE SHOULD SEE AT LEAST SOME CUMULUS BUILD-UPS.
HOWEVER, A FEW SHOWERS OR EVEN A THUNDERSTORM MAY MATERIALIZE AND
POPS WERE INCREASED TO THE 10-15 PERCENT RANGE OVER THESE AREAS FOR
SUNDAY AFTERNOON AND EVENING. BY MONDAY, THINGS LOOK MORE STABLE AS
THE TROUGH APPROACHES, AT THUS THE FORECAST GRIDS ONLY REFLECT
DEVELOPMENT OF CUMULUS IN THE AFTERNOON OVER THESE AREAS. AHEAD OF
THE INCOMING TROUGH, INCREASING SOUTHWEST FLOW WILL ALLOW FOR GOOD
MIXING AND THUS HIGH TEMPS WERE BOOSTED A COUPLE OF DEGREES OVER THE
PREVIOUS FORECAST, ESPECIALLY FOR MEMORIAL DAY BASED ON FORECAST
SOUNDINGS AND STATISTICAL GUIDANCE.
AS WE MOVE INTO THE MIDDLE OF NEXT WEEK, THE TROUGH ALOFT IS
FORECAST TO REMAIN INTO NORCAL WITH A SOUTHWEST FLOW SETTING UP
ACROSS OUR ENTIRE AREA. AS HEIGHTS SLOWLY LOWER AND TEMPS ALOFT
COOL, TEMPS AT THE SURFACE WILL ALSO GRADUALLY DROP A FEW DEGREES
EACH DAY FROM TUESDAY ONWARD, HOWEVER, THEY SHOULD STILL REMAIN AT
LEAST A FEW DEGREES ABOVE NORMAL. THE MOST NOTICEABLE DROP SHOULD BE
IN THE WESTERN CWFA WHERE IT IS POSSIBLE THE SYNOPTIC COOLING ALSO
GETS A LITTLE BOOST FROM ANY MARINE INFLUENCE THAT CAN TRICKLE
THROUGH THE COASTAL RANGE PASSES. OTHERWISE EXPECT DRY CONDITIONS
WITH A FEW CLOUDS AROUND AT TIMES.
&&
.AVIATION...FOR MCCARRAN...WIND SPEEDS UNDER 8 KTS THIS MORNING WITH
AN EASTERLY WIND COMPONENT DEVELOPING THIS AFTERNOON. CLOUDS
DEVELOPING THROUGHOUT THE DAY WITH BASES 10-12 KFT WITH LIGHT
SHOWERS POSSIBLE OVER THE SPRING MOUNTAINS AND SHEEP RANGE
THIS AFTERNOON AND EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...A LOW PRESSURE
SYSTEM WILL BE OVER SOUTHERN CALIFORNIA TODAY. ISOLATED TO SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS CAN BE EXPECTED IN AREAS TO THE
WEST OF LAS VEGAS. CLOUD BASES WILL GENERALLY BE AROUND 8-10
KFT MSL AND WILL LEAD TO PARTIAL MOUNTAIN OBSCURATION OVER THE
SOUTHERN SIERRA.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
PIERCE/STACHELSKI
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1008 AM CDT THU MAY 22 2014
.UPDATE...
ISSUED AT 1009 AM CDT THU MAY 22 2014
LATEST RAP/NAM ARE SHOWING SOME LOW TO MID LEVEL MOISTURE UNDER
THE UPPER LEVEL RIDGE SITUATED OVER THE CENTRAL DAKOTAS. THIS IS
RESULTING IN SOME HIGHER CLOUD COVER SOUTHWEST AND SOUTH CENTRAL
NORTH DAKOTA. THUS BUMPED UP CLOUD COVER MAINLY ALONG AND SOUTH OF
THE INTERSTATE TODAY. OTHERWISE UPDATED LATEST SENSIBLE WEATHER
GRIDS.
UPDATE ISSUED AT 635 AM CDT THU MAY 22 2014
NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. VERY PATCHY FOG
HAS DEVELOPED ACROSS THE TURTLE MOUNTAINS AND THROUGH THE JAMES
RIVER VALLEY AS OF 1130 UTC. HOWEVER...WITH INSOLATION INCREASING
IT SHOULD BE VERY SHORT LIVED AND LEFT IT OUT OF THE FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 22 2014
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE SLIGHT
CHANCES FOR A THUNDERSTORM SOUTHWEST LATER THIS AFTERNOON AND
EVENING...WITH SLIGHT CHANCES WEST AND CENTRAL OVERNIGHT.
CURRENTLY...UPPER LEVEL PATTERN UNCHANGED FROM 24 HOURS
AGO...WITH UPPER LEVEL LOW PRESSURE SYSTEMS OVER THE NORTHERN
GREAT LAKES AND DESERT SOUTHWEST REGIONS...WITH A RIDGE EXTENDING
FROM THE GULF OF MEXICO NORTHWEST ACROSS THE NORTHERN HIGH PLAINS.
SURFACE HIGH PRESSURE QUASI-STATIONARY ACROSS THE EASTERN DAKOTAS
AND UPPER MISSISSIPPI VALLEY. AREA OF SCT-BKN MID LEVEL CLOUDS
DEVELOPED A FEW HOURS AGO ACROSS THE SOUTHWEST...AND CONTINUE TO
SLOWLY EXPAND NORTH AND EAST. CULPRIT IS A WEAK LLJ ACROSS WESTERN
SOUTH DAKOTA NOSING INTO OUR LOCAL AREA. A FEW LIGHT RADAR ECHOS
HAVE MATERIALIZED ACROSS THE FAR SOUTH CENTRAL AROUND SIOUX
COUNTY. SINCE INSTABILITY PARAMETERS ARE NIL...WILL ADD AN
ISOLATED SHOWER ACROSS THE SOUTH THIS MORNING...SIMILAR TO THE
LATEST HRRR. WILL NEED TO KEEP AN EYE ON RADAR IN CASE COVERAGE
BECOMES GREATER.
UPPER LEVEL PATTERN REMAINS VIRTUALLY UNCHANGED FOR TODAY AND
TONIGHT. MAIN DIFFERENCE IS IN THE LOW TO MID LEVELS AS RETURN
FLOW RAMPS UP TODAY BRINGING MOISTURE ADVECTION INTO THE NORTHERN
PLAINS...HELPING TO INCREASE INSTABILITY ACROSS THE WESTERN THIRD
OF THE STATE. BUFFER DATA SUGGESTS MID LEVEL CAPPING FOR MUCH OF
THE AFTERNOON AT KISN-KDIK...SO SCALED BACK ON CONVECTION UNTIL
22Z WHEN A SUBTLE MID LEVEL WAVE IS PROJECTED TO RIDE OVER THE
RIDGE AXIS ACROSS CENTRAL MONTANA AND APPROACH MY WESTERN
COUNTIES. NOT SURE IF THIS WILL BE ENOUGH TO TRIGGER ANYTHING SO
KEPT POPS ON THE LOW SIDE AND CONFINED TO THE SOUTHWEST THROUGH
THE EVENING.
WEAK LOW LEVEL JET REDEVELOPS OVER THE WESTERN AND CENTRAL DAKOTAS
OVERNIGHT ALONG WITH ELEVATED INSTABILITY EXPANDING EAST ACROSS
CENTRAL NORTH DAKOTA. COMBINED WITH POSSIBLE EMBEDDED ENERGY
ROUNDING THE RIDGE...OPTED TO MAINTAIN SLIGHT CHANCES FOR T-STORMS
ACROSS MUCH OF THE WEST AND CENTRAL. REMOVED ACROSS THE EAST WHERE
STABLE AIR IS NO ADVERTISED.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 359 AM CDT THU MAY 22 2014
A WARM BUT CONVECTIVE LY ACTIVE MEMORIAL DAY WEEKEND WILL HIGHLIGHT
THE EXTENDED FORECAST.
GIVEN GOOD AGREEMENT AMONGST THE 00 UTC GUIDANCE SUITE...WILL
FOLLOW A BLEND FOR MOST FIELDS. LOW LEVEL MOISTURE WILL CONTINUE
TO INCREASE ACROSS WESTERN AND CENTRAL NORTH DAKOTA WITH SOUTHERLY
FLOW AHEAD OF A LEE SURFACE TROUGH FRIDAY AND SATURDAY. THE FIRST
ROUND OF SCATTERED THUNDERSTORMS IS POSSIBLE FRIDAY AFTERNOON AND
EVENING AS IMPULSES EJECTING OUT OF THE DESERT SOUTHWEST LOW
PROPAGATE ALONG THE UPPER LEVEL RIDGE INTO THE NORTHERN PLAINS.
1200-1700 J/KG OF ML CAPE IS FORECAST...HOWEVER...DEEP LAYER SHEAR
WILL BE MINIMAL FOR ORGANIZED CONVECTION...ON THE ORDER OF 15-20
KTS IN THE 0-6 KM LAYER. THUS THE THREAT FOR SEVERE WEATHER IS
RATHER LOW. THUNDERSTORM CHANCES INCREASE THROUGH THE DAY ON
SATURDAY AND CONTINUE SATURDAY NIGHT AND MUCH OF SUNDAY AS SURFACE
DEWPOINTS ARE FORECAST TO BE SOLIDLY IN THE 60S F WITH AN
INCREASING INFLUENCE OF A STRONGER NORTHERN STREAM WAVE AS THE
UPPER LEVEL RIDGE AXIS PROPAGATES DOWN STEAM OF WESTERN AND CENTRAL
NORTH DAKOTA. DEEP LAYER SHEAR STILL REMAINS BELOW FAVORED VALUES
FOR ORGANIZED CONVECTION SATURDAY...WITH THE BEST CHANCE OF SEVERE
THUNDERSTORMS POSSIBLY SUNDAY CENTRAL AS SHEAR INCREASES AS THE
SURFACE TROUGH PROPAGATES EAST THROUGH THE DAY. MEMORIAL DAY
MONDAY LOOKS DRY FOR MOST AREAS UNTIL THE NEXT WAVE EMBEDDED IN
FAST SOUTHWEST FLOW ALOFT IS FORECAST TO ARRIVE TOWARDS EVENING.
THE PATTERN OF ABOVE NORMAL TEMPERATURES AND DAILY CHANCES FOR
THUNDERSTORMS CONTINUES INTO MID WEEK WITH SOUTHWEST FLOW ALOFT
UPSTREAM OF THE UPPER LEVEL RIDGE AXIS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1009 AM CDT THU MAY 22 2014
VFR CONDITIONS ARE FORECAST ACROSS WESTERN AND CENTRAL NORTH
DAKOTA FOR THE 18 UTC TAF PERIOD. KEPT A VCTS TO KDIK FOR LATE
THIS AFTERNOON AND INTO EARLY THIS EVENING WITH ISOLATED TO
SCATTERED THUNDERSTORMS POSSIBLE ACROSS SOUTHWEST NORTH DAKOTA.
LATEST RAP IS SHOWING ACTIVITY POSSIBLE OVER THE SOUTH CENTRAL
THIS EVENING AS WELL. MIGHT ADD A VCTS INTO THE KBIS TAF ALSO.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...AYD
AVIATION...TWH
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1034 AM EDT THU MAY 22 2014
.DISCUSSION...
THE 12Z OHX SOUNDING SHOWS A STRONG CAP...AND RUC FORECAST
SOUNDINGS SHOW THIS CAP REMAINING IN PLACE THROUGH THE AFTERNOON.
IT IS STRONGEST IN SOUTHERN AREAS AND WEAKEST NORTH. THE QUESTION
IS WHETHER THERE WILL BE ENOUGH FORCING TO OVERCOME THE CAP. THE
RUC AND NAM SHOW NO UPPER LEVEL SUPPORT COMING...SO ANY CONVECTION
THAT DEVELOPS WILL NEED LOW LEVEL FORCING AND BOUNDARIES TO
DEVELOP. WE DO HAVE BOUNDARIES IN THE AREA FROM THE OVERNIGHT
SHOWERS...AND CONVECTION THAT IS EXPECTED TO INITIATE IN CNTRL KY
WILL MOVE SE..PROVIDING ADDITIONAL BOUNDARIES FOR CONVECTIVE
INITIATION. RUC AND HRRR HAVE MOST ACTIVITY IN THE PLATEAU AND
CENTRAL VALLEY.
ANY STORMS THAT FORM WILL HAVE ABUNDANT ENERGY AVAILABLE FOR
GROWTH. MLCAPE VALUES WILL APPROACH 2500 J/KG IN THE PLATEAU. THUS
LARGE HAIL APPEARS TO BE THE MAIN THREAT...WITH DAMAGING WINDS A
THREAT AS WELL AS FORECAST SOUNDINGS SHOW AN INVERTED-V PROFILE.
WHILE DEEP SHEAR VALUES WILL SUPPORT SOME SUPERCELLS...WEAK LOW
LEVEL SHEAR AND HIGH LCLS DO NOT FAVOR TORNADOES.
FOR THE UPDATE...POPS/WX/CLOUDS/QPF WILL BE ADJUSTED TO BETTER
MATCH FAVORED PRECIP AREAS...AND TO ADD A MENTION OF THE LARGE
HAIL/DAMAGING WIND THREAT. TEMPERATURES APPEAR ON TRACK.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
320 PM MST THU MAY 22 2014
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
AN AREA OF LOW PRESSURE TRACKING SLOWLY ACROSS THE DESERT SOUTHWEST
WILL LEAD TO A SLIGHT CHANCE OF THUNDERSTORMS FRIDAY ACROSS THE
REGION. STORM CHANCES WILL BE LIMITED TO THE HIGHER TERRAIN OF
SOUTH-CENTRAL ARIZONA ON SATURDAY. A SLOW WARMING TREND WILL BEGIN
OVER SOUTHEAST CALIFORNIA FRIDAY AND EXPAND EASTWARD OVER THE
WEEKEND. ANTICIPATE TEMPERATURES AT LEAST A FEW DEGREES ABOVE NORMAL
BY MONDAY WITH LITTLE CHANGE THROUGH THURSDAY.
&&
.DISCUSSION...
REST OF TODAY THROUGH SUNDAY...
SCATTERED THUNDERSTORMS HAVE DEVELOPED THIS AFTERNOON OVER SOUTHERN
CALIFORNIA...MAINLY OVER THE HIGHER MOUNTAINS AND
DESERTS...INCLUDING EASTERN RIVERSIDE AND FAR WESTERN IMPERIAL
COUNTIES. LESSER ACTIVITY HAS ALSO OCCURRED OVER THE EASTERN THIRD
OF ARIZONA...JUST BRUSHING EASTERN PORTIONS OF GILA COUNTY. FOR OUR
AREA THE MOST SIGNIFICANT ACTIVITY HAS BEEN OVER EASTERN RIVERSIDE
COUNTY INCLUDING JOSHUA TREE NATIONAL PARK. THE STORMS ARE DUE TO AN
UPPER LOW CENTERED OVER THE MOHAVE DESERT BRINGING SOME MOISTURE AND
DESTABILIZATION WITH IT. AN EMBEDDED VORT MAX ON THE SOUTHERN END OF
THE SYSTEM MAY ALSO BE PROVIDING SOME QG FORCING AS WELL. HI-RES
MODELS INCLUDING THE HRRR HAVE DONE A GOOD JOB DEPICTING THE
CONVECTION. PRECIP PRODUCTION TURNS OUT TO HAVE BEEN BETTER THAN
ANTICIPATED. HAVE NOT HAD ANY DIRECT REPORTS OF FLOODING OR VERY
STRONG WINDS FOR OUR AREA BUT FLASH FLOODING WAS REPORTED IN THE SAN
DIEGO COUNTY DESERTS NEAR BORREGO SPRINGS. QUITE IMPRESSIVE GIVEN
THE MODEST PWAT VALUES. BREEZY CONDITIONS CONTINUE OVER PORTIONS OF
SOUTH-CENTRAL ARIZONA INCLUDING NORTHERN PINAL COUNTY AND THE HIGHER
TERRAIN EAST OF PHOENIX. COULD SEE SOME LOCALIZED DUST OVER OUR MOST
DUST PRONE AREAS. THUNDERSTORM ACTIVITY WILL TRAIL OFF THIS EVENING
AS SURFACE HEATING IS LOST. NOT INCONCEIVABLE THAT A STRAY SHOWER
POPS UP OVERNIGHT AS THE VORT MAX MOVES EASTWARD. THE LOW CENTER IS
EXPECTED TO SHIFT EASTWARD A BIT FRIDAY. THE FOCUS APPEARS TO BE
AREAS ABOVE 2000 FT IN ELEVATION OVER LA PAZ AND WESTERN MARICOPA
COUNTY. INTERESTINGLY...THE MODELS ALSO TEND TO AGREE THAT THE
HIGHER TERRAIN EAST OF PHOENIX WILL NOT SEE MUCH ACTIVITY. HELD ON
TO THE SLIGHT CHANCE POPS THERE BUT EXPANDED THE SLIGHT CHANCES TO
THE LOWER ELEVATIONS ACROSS THE WHOLE FORECAST AREA. SOUTHEAST
CALIFORNIA SHOULD BE MORE STABLE FRIDAY AND THUS LESS ACTIVE BUT
STILL KEEPING A SLIGHT CHANCE. SATURDAY...THE LOW CONTINUES MOVING
SLOWLY EAST AND THUS BEST INSTABILITY WILL BE OVER EASTERN HALF OF
ARIZONA. MODELS AGREE THAT FOR OUR AREA...THE HIGHER TERRAIN EAST OF
PHOENIX WILL HAVE THE BEST CHANCE OF CONVECTION...WITH SOME SPILL-
OVER INTO FAR NORTHERN MARICOPA COUNTY INCLUDING NORTHERN PORTIONS
OF THE PHOENIX AREA. ON SUNDAY...THE SYSTEM IS MOSTLY INTO NEW
MEXICO AND THERE IS ONLY A LINGERING VERY SLIGHT CHANCE OF
CONVECTION OVER SOUTHEAST GILA COUNTY. AS FOR TEMPERATURES...A
WARMING TREND WILL BEGIN FRIDAY OVER SOUTHEAST
CALIFORNIA...EXPANDING TO SOUTHWEST ARIZONA SATURDAY...THEN REACHING
SOUTH-CENTRAL ARIZONA SUNDAY.
MONDAY THROUGH THURSDAY...
THE UPPER LOW WILL EVENTUALLY MOVE BACK INTO THE MEAN STORM FLOW AND
CLEAR OUT OF THE SOUTHWEST STATES BY LATE MONDAY...LEAVING SUBTLE
RIDGE HEIGHTS OVERHEAD. UPPER LEVEL HEIGHTS QUICKLY BUILD BACK INTO
THE UPPER 580DM RANGE...WARMING TEMPERATURES BACK TO NORMAL AND THEN
ABOVE NORMAL READINGS BY EARLY NEXT WEEK. RIDGE HEIGHTS LOOK TO PEAK
BY TUESDAY/WEDNESDAY AS THE RIDGE AXIS MOVES INTO NEW MEXICO...WHILE
LONGWAVE TROUGHING DEVELOPS OFF THE WEST COAST.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...ISOLATED
CONVECTION IS EXPECTED TO THIS AFTERNOON INTO EARLY EVENING HOURS
WELL EAST OF THE PHOENIX TERMINALS ACROSS EASTERN AZ. ACROSS THE
PHOENIX AREA...AFTERNOON BREEZINESS AGAIN EXPECTED UNTIL 06Z WITH
OCCASIONAL GUSTS AS HIGH AS 20 KT. A RETURN TO LIGHTER DOWNSLOPE
EASTERLY FLOW IS EXPECTED AFTER 08Z FRIDAY.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ISOLATED THUNDERSTORM CHANCES WILL CONTINUE THROUGH 06Z FRIDAY
ACROSS SOUTHEASTERN CA. STORMS ARE EXPECTED TO REMAIN CONFINED TO
THE HIGHER TERRAIN EAST OF SAN DIEGO AND TOWARDS JOSHUA TREE
NATIONAL PARK AND ALONG INTERSTATE 10 TOWARDS BLYTHE. THERE IS A
REMOTE POSSIBILITY THAT AN ISOLATED CELL WILL AFFECT KIPL/KBLH WITH
BRIEF GUSTY WINDS...AND CONFIDENCE IS LOW SO NO MENTION IN THE TAFS
AT THIS TIME. OTHERWISE...WINDS WILL PREDOMINATELY REMAIN OUT OF THE
SOUTH AND WEST...WITH GUSTS UP TO 20 KT INTO THIS EVENING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
THE SLOW MOVING LOW PRESSURE SYSTEM WILL FINALLY MAKE AN EXIT FROM
THE REGION MOVING EASTWARD. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE ACROSS NORTHEASTERN AZ THROUGH
SUNDAY...THOUGH RAIN CHANCES WILL BE CONSIDERABLY LESS ACROSS THE
LOWER DESERTS. ISOLATED DRY THUNDERSTORMS WILL ALSO REMAIN A THREAT
AS WELL...PARTICULARLY ACROSS THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX...AS THE AIR MASS WILL REMAIN VERY DRY WITH LOW HUMIDITY
VALUES. WINDS WILL GENERALLY REMAIN LIGHT...EXCEPT IN THE VICINITY
OF THUNDERSTORMS. A WARMING AND DRYING TREND IS EXPECTED WITH ABOVE
AVERAGE TEMPERATURES LIKELY BY MONDAY AND CONTINUING THROUGH MIDWEEK.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ/NOLTE
AVIATION....DEWEY
FIRE WEATHER...DEWEY/HIRSCH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
310 PM MST THU MAY 22 2014
.SYNOPSIS...
AN AREA OF LOW PRESSURE TRACKING SLOWLY ACROSS THE DESERT SOUTHWEST
WILL LEAD TO A SLIGHT CHANCE OF THUNDERSTORMS FRIDAY ACROSS THE
REGION. STORM CHANCES WILL BE LIMITED TO THE HIGHER TERRAIN OF
SOUTH-CENTRAL ARIZONA ON SATURDAY. A SLOW WARMING TREND WILL BEGIN
OVER SOUTHEAST CALIFORNIA FRIDAY AND EXPAND EASTWARD OVER THE
WEEKEND. ANTICIPATE TEMPERATURES AT LEAST A FEW DEGREES ABOVE NORMAL
BY MONDAY WITH LITTLE CHANGE THROUGH THURSDAY.
&&
.DISCUSSION...
REST OF TODAY THROUGH SUNDAY...
SCATTERED THUNDERSTORMS HAVE DEVELOPED THIS AFTERNOON OVER SOUTHERN
CALIFORNIA...MAINLY OVER THE HIGHER MOUNTAINS AND
DESERTS...INCLUDING EASTERN RIVERSIDE AND FAR WESTERN IMPERIAL
COUNTIES. LESSER ACTIVITY HAS ALSO OCCURRED OVER THE EASTERN THIRD
OF ARIZONA...JUST BRUSHING EASTERN PORTIONS OF GILA COUNTY. FOR OUR
AREA THE MOST SIGNIFICANT ACTIVITY HAS BEEN OVER EASTERN RIVERSIDE
COUNTY INCLUDING JOSHUA TREE NATIONAL PARK. THE STORMS ARE DUE TO AN
UPPER LOW CENTERED OVER THE MOHAVE DESERT BRINGING SOME MOISTURE AND
DESTABILIZATION WITH IT. AN EMBEDDED VORT MAX ON THE SOUTHERN END OF
THE SYSTEM MAY ALSO BE PROVIDING SOME QG FORCING AS WELL. HI-RES
MODELS INCLUDING THE HRRR HAVE DONE A GOOD JOB DEPICTING THE
CONVECTION. PRECIP PRODUCTION TURNS OUT TO HAVE BEEN BETTER THAN
ANTICIPATED. HAVE NOT HAD ANY DIRECT REPORTS OF FLOODING OR VERY
STRONG WINDS FOR OUR AREA BUT FLASH FLOODING WAS REPORTED IN THE SAN
DIEGO COUNTY DESERTS NEAR BORREGO SPRINGS. QUITE IMPRESSIVE GIVEN
THE MODEST PWAT VALUES. BREEZY CONDITIONS CONTINUE OVER PORTIONS OF
SOUTH-CENTRAL ARIZONA INCLUDING NORTHERN PINAL COUNTY AND THE HIGHER
TERRAIN EAST OF PHOENIX. COULD SEE SOME LOCALIZED DUST OVER OUR MOST
DUST PRONE AREAS. THUNDERSTORM ACTIVITY WILL TRAIL OFF THIS EVENING
AS SURFACE HEATING IS LOST. NOT INCONCEIVABLE THAT A STRAY SHOWER
POPS UP OVERNIGHT AS THE VORT MAX MOVES EASTWARD. THE LOW CENTER IS
EXPECTED TO SHIFT EASTWARD A BIT FRIDAY. THE FOCUS APPEARS TO BE
AREAS ABOVE 2000 FT IN ELEVATION OVER LA PAZ AND WESTERN MARICOPA
COUNTY. INTERESTINGLY...THE MODELS ALSO TEND TO AGREE THAT THE
HIGHER TERRAIN EAST OF PHOENIX WILL NOT SEE MUCH ACTIVITY. HELD ON
TO THE SLIGHT CHANCE POPS THERE BUT EXPANDED THE SLIGHT CHANCES TO
THE LOWER ELEVATIONS ACROSS THE WHOLE FORECAST AREA. SOUTHEAST
CALIFORNIA SHOULD BE MORE STABLE FRIDAY AND THUS LESS ACTIVE BUT
STILL KEEPING A SLIGHT CHANCE. SATURDAY...THE LOW CONTINUES MOVING
SLOWLY EAST AND THUS BEST INSTABILITY WILL BE OVER EASTERN HALF OF
ARIZONA. MODELS AGREE THAT FOR OUR AREA...THE HIGHER TERRAIN EAST OF
PHOENIX WILL HAVE THE BEST CHANCE OF CONVECTION...WITH SOME SPILL-
OVER INTO FAR NORTHERN MARICOPA COUNTY INCLUDING NORTHERN PORTIONS
OF THE PHOENIX AREA. ON SUNDAY...THE SYSTEM IS MOSTLY INTO NEW
MEXICO AND THERE IS ONLY A LINGERING VERY SLIGHT CHANCE OF
CONVECTION OVER SOUTHEAST GILA COUNTY. AS FOR TEMPERATURES...A
WARMING TREND WILL BEGIN FRIDAY OVER SOUTHEAST
CALIFORNIA...EXPANDING TO SOUTHWEST ARIZONA SATURDAY...THEN REACHING
SOUTH-CENTRAL ARIZONA SUNDAY.
MONDAY THROUGH THURSDAY...
THE UPPER LOW WILL EVENTUALLY MOVE BACK INTO THE MEAN STORM FLOW AND
CLEAR OUT OF THE SOUTHWEST STATES BY LATE MONDAY...LEAVING SUBTLE
RIDGE HEIGHTS OVERHEAD. UPPER LEVEL HEIGHTS QUICKLY BUILD BACK INTO
THE UPPER 580DM RANGE...WARMING TEMPERATURES BACK TO NORMAL AND THEN
ABOVE NORMAL READINGS BY EARLY NEXT WEEK. RIDGE HEIGHTS LOOK TO PEAK
BY TUESDAY/WEDNESDAY AS THE RIDGE AXIS MOVES INTO NEW MEXICO...WHILE
LONGWAVE TROUGHING DEVELOPS OFF THE WEST COAST.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
ISOLATED CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON WELL EAST
OF THE PHOENIX TERMINALS ACROSS EASTERN AZ. ACROSS THE PHOENIX
AREA...AFTERNOON BREEZINESS WILL AGAIN BE PREVALENT WITH OCCASIONAL
GUSTS AS HIGH AS 20 KT. A RETURN TO LIGHTER DOWNSLOPE EASTERLY FLOW
IS EXPECTED BETWEEN 06Z AND 08Z FRIDAY.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ISOLATED THUNDERSTORMS ARE LIKELY ACROSS SOUTHEASTERN CA THIS
AFTERNOON AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. STORMS WILL
GENERALLY REMAIN CONFINED TO THE HIGHER TERRAIN EAST OF SAN DIEGO
AND TOWARDS JOSHUA TREE NATIONAL PARK. HOWEVER...THERE IS A REMOTE
POSSIBILITY THAT AN ISOLATED CELL WILL AFFECT KIPL/KBLH WITH BRIEF
GUSTY WINDS. OTHERWISE...WINDS WILL PREDOMINATELY REMAIN OUT OF THE
SOUTH AND WEST...WITH GUSTS UP TO 20 KT LATE THIS AFTERNOON AND THIS
EVENING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
A LOW PRESSURE SYSTEM WILL CONTINUE MOVING SLOWLY EASTWARD THROUGH
AZ THIS WEEKEND. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE ACROSS NORTHEASTERN AZ THROUGH SUNDAY...THOUGH RAIN
CHANCES WILL BE CONSIDERABLY LESS ACROSS THE LOWER DESERTS. ISOLATED
DRY THUNDERSTORMS WILL ALSO REMAIN A THREAT AS WELL...PARTICULARLY
ACROSS THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX. WINDS WILL
GENERALLY REMAIN LIGHT...EXCEPT IN THE VICINITY OF THUNDERSTORMS.
AFTER SOMEWHAT COOLER CONDITIONS SATURDAY...A WARMING AND DRYING
TREND IS EXPECTED WITH ABOVE AVERAGE TEMPERATURES LIKELY BY MONDAY
AND CONTINUING THROUGH MIDWEEK.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ/NOLTE
AVIATION....HIRSCH
FIRE WEATHER...HIRSCH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1005 AM MST THU MAY 22 2014
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL SLOWLY MOVE THROUGH THE DESERT SOUTHWEST
TODAY THROUGH THE EARLY WEEKEND...KEEPING DAYTIME HIGHS BELOW NORMAL.
THERE WILL BE A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS
OVER THE HIGHER TERRAIN OF THE FORECAST AREA AS THE LOW MOVES THROUGH
THE REGION. A GRADUAL WARMING TREND WILL BEGIN FROM WEST TO EAST
WITH ABOVE NORMAL TEMPERATURES RETURNING BY EARLY NEXT WEEK.
&&
.DISCUSSION...
UPPER LOW CENTERED OVER THE MOHAVE DESERT REGION OF CALIFORNIA AND
NEVADA THIS MORNING. TWO VORT LOBES ARE EVIDENT IN THE WATER VAPOR
IMAGERY...NORTH AND SOUTH OF THE SYSTEM CENTER. BLENDED TPW IMAGERY
SHOWS OVER 2/3 INCH OF PWATER NEAR AND WEST OF THE LOWER COLORADO
RIVER VALLEY. ISOLATED CONVECTION HAS ALREADY STARTED ON/NEAR MT.
SAN GORGONIO WHICH IS NOT FAR WEST/NORTHWEST OF JOSHUA TREE NATIONAL
PARK. 12Z NCEP MODELS ARE MORE AGGRESSIVE THAN SOME PREVIOUS RUNS
WITH THE PRECIP OVER SOUTHERN CALIFORNIA TODAY...MAINLY HUGGING THE
HIGHER TERRAIN. HI RES MODELS INCLUDING HRRR AND LOCAL WRF AND NMM
ALSO DEPICT CONVECTION DEVELOPING OVER OUR PORTION OF CALIFORNIA
TODAY. IN FACT...SOME ADDITIONAL UPWARD ADJUSTMENTS TO THE POPS MAY
NEED TO BE MADE IN EASTERN RIVERSIDE COUNTY AND WESTERN IMPERIAL
COUNTY FOR TODAY. TO THE EAST...OVER THE EASTERN THIRD OF ARIZONA
INCLUDING SOUTHERN GILA COUNTY...MODELS ARE NOT AS ENTHUSIASTIC WITH
CONVECTION BUT STILL DEPICT SOME MODEST DEVELOPMENT. ANTICIPATE
SOMETHING OF A REPEAT FOR FRIDAY THOUGH CONVECTION EXCEPT FOR
SOMEWHAT OF AN EASTERN SHIFT IN THE ISOLATED/SCATTERED CONVECTION.
MORE LATER.
&&
.PREVIOUS DISCUSSION ISSUED 257 AM...
SKIES OVERNIGHT HAVE REMAINED MOSTLY CLEAR...WITH ONLY A FEW CU
ACROSS FAR EASTERN GILA COUNTY AND EVEN FEWER WISPS OF CIRRUS OUT
OVER THE SOUTHEAST CALIFORNIA DESERTS. BROAD UPPER LOW CURRENTLY
CIRCULATING TO OUR NORTHWEST WITH ONE IN A SERIES OF VORT MAXES
ROTATING AROUND THE BASE JUST MOVING INLAND OVER NORTHERN BAJA PER
WATER VAPOR IMAGERY. IN THE WAKE OF WEDNESDAY`S SLOW FRONTAL
PASSAGE...A SLIGHTER COOLER AIR MASS WAS OBSERVED OVER THE FORECAST
AREA ON EVENING RAOBS. EXPECT LITTLE CHANGE IN TODAY`S HIGH
TEMPERATURES FROM WEDNESDAY`S WITH VERY LITTLE WAA DESPITE SOUTHWEST
FLOW THROUGH THE COLUMN.
THE UPPER LOW WILL SLOWLY DIG INTO CALIFORNIA TODAY AND EVENTUALLY
BEGIN A SLOW TRANSITION EASTWARD IN ARIZONA FOR FRIDAY AND SATURDAY.
PRECIPITATION CHANCES WERE INCREASED OVER THE MOUNTAINS OF JTNP AND
DOWN INTO THE NEARBY SOUTHEAST CALIFORNIA DESERTS FOR THIS AFTERNOON
AND EVENING AS THE LOW CENTER AND COOL POOL ALOFT MOVES RIGHT THROUGH
THAT REGION. BLENDED TPW SATELLITE PLOT SHOWING ANYWHERE FROM 0.60 TO
0.80 INCHES OVER SOUTHERN CALIFORNIA...HOWEVER SOUNDING PROFILES KEEP
MOST OF THAT MOISTURE THROUGH THE MID-LEVELS WITH DRY SUB-CLOUD
LAYERS...LEADING TO STRONG GUSTY WINDS THE BIGGER THREAT THAN WETTING
RAINS. EXPECT THE BULK OF THE ACTIVITY TO BE DIURNALLY DRIVEN...SO
OUTSIDE OF SOME LINGERING CLOUDS OVERNIGHT...SHOWER/THUNDERSHOWER
ACTIVITY SHOULD DISSIPATE AFTER SUNSET ACROSS SOUTHEAST CALIFORNIA.
BY FRIDAY...THE LOW CIRC CENTER AND 500MB/700MB COOL POOL WILL MOVE
FULLY INTO ARIZONA. ADDITIONAL VORT ENERGY AND DIFLUENT MOTION
THROUGH THE ATMO UPPER LAYERS KEPT AT LEAST SLIGHT CHANCES GOING OVER
THE SOUTH-CENTRAL ARIZONA HIGH TERRAIN...INCLUDING PORTIONS OF
WESTERN MARICOPA COUNTY. MOISTURE AVAILABILITY REMAINS LIMITED...WITH
FORECAST SOUNDINGS NEVER PRESENTING ANY LAYERS NEAR ENOUGH TO
SATURATION TO WARRANT QPF...ESPECIALLY OVER THE LOWER DESERTS. THE
SET-UP IS STILL THERE FOR AFTERNOON AND EVENING HIGH-BASED
DEVELOPMENT OVER THE HIGHER TERRAIN TO THE EAST OF PHOENIX AND ACROSS
EASTERN ARIZONA...WITH STRONG GUSTY WINDS AND EVEN SOME LIGHTNING
STRIKES POSSIBLE BOTH FRIDAY AND SATURDAY. DAYTIME TEMPERATURES WILL
BEGIN TO WARM ACROSS SOUTHEAST CALIFORNIA FOR FRIDAY AND THEN WARMING
WILL EXPAND INTO THE ARIZONA BY THE WEEKEND WITH WIDESPREAD 90S...AND
EVEN SOME LOW 100S...POSSIBLE BY SUNDAY AS THE LOW EXITS INTO NEW
MEXICO.
THE UPPER LOW WILL EVENTUALLY MOVE BACK INTO THE MEAN STORM FLOW AND
CLEAR OUT OF THE SOUTHWEST STATES BY LATE MONDAY...LEAVING SUBTLE
RIDGE HEIGHTS OVERHEAD. UPPER LEVEL HEIGHTS QUICKLY BUILD BACK INTO
THE UPPER 580DM RANGE...WARMING TEMPERATURES BACK TO NORMAL AND THEN
ABOVE NORMAL READINGS BY EARLY NEXT WEEK. RIDGE HEIGHTS LOOK TO PEAK
BY TUESDAY/WEDNESDAY AS THE RIDGE AXIS MOVES INTO NEW MEXICO...WHILE
LONGWAVE TROUGHING DEVELOPS OFF THE WEST COAST.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
ISOLATED CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON WELL EAST
OF THE PHOENIX TERMINALS ACROSS EASTERN AZ. ACROSS THE PHOENIX
AREA...AFTERNOON BREEZINESS WILL AGAIN BE PREVALENT WITH OCCASIONAL
GUSTS AS HIGH AS 20 KT. A RETURN TO LIGHTER DOWNSLOPE EASTERLY FLOW
IS EXPECTED BETWEEN 06Z AND 08Z FRIDAY.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ISOLATED THUNDERSTORMS ARE LIKELY ACROSS SOUTHEASTERN CA THIS
AFTERNOON AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. STORMS WILL
GENERALLY REMAIN CONFINED TO THE HIGHER TERRAIN EAST OF SAN DIEGO
AND TOWARDS JOSHUA TREE NATIONAL PARK. HOWEVER...THERE IS A REMOTE
POSSIBILITY THAT AN ISOLATED CELL WILL AFFECT KIPL/KBLH WITH BRIEF
GUSTY WINDS. OTHERWISE...WINDS WILL PREDOMINATELY REMAIN OUT OF THE
SOUTH AND WEST...WITH GUSTS UP TO 20 KT LATE THIS AFTERNOON AND THIS
EVENING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
A LOW PRESSURE SYSTEM WILL CONTINUE MOVING SLOWLY EASTWARD THROUGH
AZ THIS WEEKEND. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE ACROSS NORTHEASTERN AZ THROUGH SUNDAY...THOUGH RAIN
CHANCES WILL BE CONSIDERABLY LESS ACROSS THE LOWER DESERTS. ISOLATED
DRY THUNDERSTORMS WILL ALSO REMAIN A THREAT AS WELL...PARTICULARLY
ACROSS THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX. WINDS WILL
GENERALLY REMAIN LIGHT...EXCEPT IN THE VICINITY OF THUNDERSTORMS.
AFTER SOMEWHAT COOLER CONDITIONS SATURDAY...A WARMING AND DRYING
TREND IS EXPECTED WITH ABOVE AVERAGE TEMPERATURES LIKELY BY MONDAY
AND CONTINUING THROUGH MIDWEEK.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...NOLTE
AVIATION....HIRSCH
FIRE WEATHER...HIRSCH
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
145 PM PDT THU MAY 22 2014
.SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE
MOUNTAINS AND DESERTS THROUGH THIS EVENING...WITH ISOLATED SHOWERS
AND THUNDERSTORMS POSSIBLE WEST OF THE MOUNTAINS. ALTHOUGH DRIER
CONDITIONS WILL DEVELOP ON FRIDAY...AS THE TROUGH MOVES EAST...SOME
LINGERING INSTABILITY AND MOISTURE WILL CONTINUE THE THREAT OF
SHOWERS OVER THE MOUNTAINS AND DESERTS. DRY AND WARMER CONDITIONS
WILL THEN DEVELOP FOR THE HOLIDAY WEEKEND...WITH SOME COASTAL LOW
CLOUDS AND FOG POSSIBLE EACH NIGHT. A GRADUAL COOLING TREND WILL
THEN DEVELOP FOR THE MIDDLE AND LATTER PART OF THE WORK WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW OVER SOUTHERN
CALIFORNIA THIS AFTERNOON. AS A RESULT...SCATTERED SHOWERS AND
THUNDERSTORMS ARE DEVELOPING OVER THE MOUNTAINS AND DESERTS.
CURRENTLY...AN URBAN AND SMALL STREAM FLOOD ADVISORY IS IN EFFECT
FOR A PORTION OF THE SAN DIEGO COUNTY DESERTS...EAST OF SHELTER
VALLEY. MEANWHILE...A THICK BLANKET OF LOW CLOUDS LINGERS WEST OF
THE MOUNTAINS. ALTHOUGH THERE ARE A FEW BREAKS IN THE
CLOUDS...MAINLY OVER THE INLAND EMPIRE...THERE ARE NOW ENOUGH HIGH
CLOUDS LIMITING THE SURFACE HEATING. THE HRRR AND LOCAL WRF ARE
STILL INDICATING THAT THE ELSINORE CONVERGENCE ZONE WILL GENERATE
SOME ACTIVITY LATE THIS AFTERNOON AND DURING THE EARLY EVENING
HOURS...SO HAVE KEPT A MENTION OF SHOWERS AND THUNDERSTORMS IN THE
FORECAST FOR THE INLAND VALLEYS. HOWEVER...CONFIDENCE IS LOW GIVEN
THE CURRENT SATELLITE TRENDS.
THIS UPPER LEVEL TROUGH WILL SLOWLY SHIFT EAST TONIGHT AND DURING
THE DAY ON FRIDAY. AS A RESULT...MOST AREAS WILL SEE DRIER AND
WARMER CONDITIONS DEVELOP. HOWEVER...THERE WILL BE ENOUGH LINGERING
INSTABILITY AND MOISTURE OVER THE MOUNTAINS AND DESERTS...THAT
ISOLATED SHOWERS AND THUNDERSTORMS COULD DEVELOP ONCE AGAIN. HIGH
PRESSURE THEN BUILD BACK ACROSS SOUTHERN CALIFORNIA FOR THE MEMORIAL
DAY WEEKEND...WITH EVEN WARMER AND DRIER CONDITIONS DEVELOPING. A
SHALLOW MARINE LAYER WILL REMAIN ALONG THE COAST THOUGH...WITH NIGHT
AND MORNING LOW CLOUDS AND FOG POSSIBLE. ANOTHER TROUGH WILL THEN
DIG ALONG THE WEST COAST BY THE MIDDLE PART OF THE WORK WEEK...WITH
COOLER CONDITIONS AND A MORE EXTENSIVE MARINE LAYER DEVELOPING ONCE
AGAIN.
&&
.AVIATION...
222000Z...COAST/VALLEYS...AREAS OF LOW CLOUDS WITH BKN-OVC CIGS
2500-4000 FT MSL LAYERED TO 15000 FT. HIGHER TERRAIN WILL BE
OBSCURED WITH AREAS OF FOG REDUCING VIS TO 3-5SM WHERE CLOUDS AND
TERRAIN INTERSECT. LOW CLOUDS BECOME WIDESPREAD AGAIN AFTER 03Z FRI
WITH OVC BASES 2000-3000 FT MSL AND TOPS NEAR 6000 FT
MSL...OBSCURING HIGHER TERRAIN. PARTIAL CLEARING TO THE COAST AFT
18Z FRI.
MTNS/DESERTS...ISOLATED-SCT SHOWERS AND TSTMS THROUGH 05Z FRI.
&&
.MARINE...
200 PM...ISOLATED SHOWERS POSSIBLE OVER THE COASTAL WATERS THIS
AFTERNOON. NO HAZARDOUS MARINE WEATHER IS EXPECTED FRIDAY THROUGH
SUNDAY.
&&
.FIRE WEATHER...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE
MOUNTAINS AND DESERTS THROUGH THIS EVENING...WITH ISOLATED SHOWERS
AND THUNDERSTORMS POSSIBLE WEST OF THE MOUNTAINS...AS A COLD TROUGH
OF LOW PRESSURE REMAINS OVER SOUTHERN CALIFORNIA. BRIEF AND LOCALLY
HEAVY RAIN WILL CONTINUE TO BE POSSIBLE...WITH THESE THUNDERSTORMS.
ALTHOUGH WETTING RAINS MAY OCCUR...THERE IS STILL THE POSSIBILITY OF
LIGHTNING STRIKES STARTING FIRES OUTSIDE OF THE SHOWERS.
A FEW SHOWERS MAY DEVELOP OVER THE MOUNTAINS AND DESERTS AGAIN ON
FRIDAY AFTERNOON. DRY AND WARMER CONDITIONS WILL DEVELOP FOR THIS
HOLIDAY WEEKEND.
&&
.SKWYARN...
SKYWARN ACTIVATION IS REQUESTED FOR SAN BERNARDINO...RIVERSIDE...AND
SAN DIEGO COUNTIES.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC/FIRE WEATHER...PALMER
AVIATION/MARINE...PG
AREA FORECAST DISCUSSION
NWS TAUNTON MA
335 PM EDT THU MAY 22 2014
.SYNOPSIS...
LOW PRESSURE WILL BRING OCCASIONAL SHOWERY WEATHER AND COOL
TEMPERATURES INTO SATURDAY. TURNING MILDER SUNDAY THEN WARM AND
DRY CONDITIONS EXPECTED FOR MEMORIAL DAY. A WEAK FRONT MAY BRING
SCATTERED SHOWERS TUESDAY INTO EARLY WEDNESDAY ALONG WITH COOLER
TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
BAND OF SHOWERS MOVING ACROSS E MA AND THE HRRR HAS THE SHOWERS
LINGERING ALONG THE COAST UNTIL 21-22Z. SCT STRONG TO SEVERE
STORMS ACROSS E NY AND E PA ARE FIRING IN AXIS OF MAX INSTABILITY
WITH MLCAPES UP TO 1500 J/KG. THERE IS NO SFC INSTABILITY ACROSS
SNE AND WE EXPECT CONVECTION TO WEAKEN AS IT MOVES INTO SNE
THROUGH THIS EVENING...WITH THE HRRR CONCENTRATING THE SHOWERS IN
THE WEST THIS EVENING.
LATER TONIGHT...THERE IS SOME MID LEVEL DRYING MOVING IN FROM THE
SW AND SNE WILL BE IN BETWEEN SHORTWAVES FOR A TIME SO IT COULD BE
MOSTLY DRY IN THE OVERNIGHT PERIOD. ABUNDANT LOW LEVEL MOISTURE
WILL LEAD TO AREAS OF STRATUS AND FOG.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
FRIDAY...
STRONGER SHORTWAVE WILL BE DIGGING SE FROM THE GT LAKES WITH SHARP
TROF APPROACHING FROM THE WEST. WHILE LOW PRES WILL BE CUTTING TO
THE S OF NEW ENG AN INVERTED TROF SETS UP ACROSS FAR W NEW ENG IN
RESPONSE TO THE STRONG SHORTWAVE. THIS IS WHERE WE EXPECT THE MAIN
FOCUS FOR SHOWERS TO BE...BUT SCT SHOWERS EXPECTED FURTHER TO THE
EAST AS MOISTURE DEEPENS WITH PERSISTENT QG FORCING. MODELS
INDICATE SOME WEAK SFC INSTABILITY IN THE WEST SO POTENTIAL FOR A
FEW TSTMS AS WELL. INCREASING LOW LEVEL EASTERLY FLOW WILL RESULT
IN COOLER TEMPS WITH MAXES UPPER 50S TO LOWER 60S.
FRIDAY NIGHT...
SHOWERS AND ISOLD TSTMS CONTINUE INTO THE EVENING AS THE TROF
MOVES ACROSS SNE WITH LOW PRES PASSING TO THE SE. MODELS KEEP THE
FOCUS IN WESTERN NEW ENG WHERE BEST LOW LEVEL CONVERGENCE AND MID
LEVEL OMEGA. AS THE TROF SHIFTS TO THE EAST OVERNIGHT A DECREASE
IN THE SHOWERS EXPECTED. MORE STRATUS AND PATCHY FOG LIKELY GIVEN
PERSISTENT LOW LEVEL MOISTURE AND EAST FLOW.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
HIGHLIGHTS...
- WEEKEND CHANCES OF SHOWERS/THUNDERSTORMS ACROSS THE INTERIOR
- NICE AND MILD FOR MEMORIAL DAY
- ANOTHER SHOT OF WET WEATHER FOR TUESDAY
- CLASH OF AIRMASSES AND UNCERTAIN WEATHER FOR THE REST OF THE WEEK
/ OVERVIEW AND MODEL PREFERENCE...
AN UNSTABLE LONG-TERM FORECAST BY NEXT WEEK AS EXHIBITED BY THE NAO
TREND. YESTERDAY NEAR-NEUTRAL WITH A NEGATIVE TREND HAS NOW SHIFTED
POSITIVE TOWARDS THE END OF MAY. THOUGH THE NAEFS/CANADIAN CONTINUES
TO EXHIBIT A POSITIVE HEIGHT ANOMALY OVER THE HUDSON BAY REGION...
THE TREND OF ABOVE AVERAGE TEMPERATURES HAS SOMEWHAT DIMINISHED.
SO CONSIDERING THE LOW LIFTING INTO THE CENTRAL PLAINS...THE RIDGE
SHOULD STRENGTHEN AHEAD. BUT AN ICELANDIC LOW PROVIDING THE MEANS OF
DOWNSTREAM BLOCKING APPEARS TO LIMIT THE PROGRESSIVENESS OF THE LONG-
WAVE FLOW AND THEREBY RESULTS IN TROUGHING LINGERING IN PROXIMITY TO
NEW ENGLAND AND ACROSS THE NW-ATLANTIC. THIS POINT IS EXACERBATED BY
A COMPARISON OF GEFS RUNS WHICH SHOWS A TREND TOWARDS A STRONGER
INFLUENCE OF THE W-PERIPHERY OF THE TROUGH RESULTING IN COOLER AIR
ALOFT ACROSS THE REGION. WPC NOTES THE ECENS IS DEEPER WITH THE
TROUGH WHEREAS THE GEFS IS SHARPER AND SLOWER. THE NAEFS IS THE
MIDDLE GROUND. THUS AM EXPECTING A CLASH OF AIRMASSES ACROSS THE NE-
CONUS WITH WARMER AIR SW AND COOLER AIR NE.
HAVE HIGH CONFIDENCE IN THE FORECAST THROUGH MONDAY USING A MODEL
CONSENSUS BLEND. SPREAD INCREASES BY TUESDAY...SO WILL LEAN MORE
TOWARDS MODEL ENSEMBLE MEANS KEEPING THE TROUGH IN CLOSER PROXIMITY
TO THE NE-CONUS AND HOLDING COOLER CONDITIONS ACROSS THE REGION AND
LIMITING THE INFLUENCE OF THE RIDGE FROM THE W.
/ DAY-TO-DAY DETAILS...
SATURDAY...
INVERTED TROUGH IS THE FOCUS OF LOCALIZED CONVERGENCE BENEATH WEAK
DISTURBANCES ALOFT WHICH WILL YIELD SOME MEASURE OF LIFT. NOTING
COOLER AIR WRAPPING REARWARD OF THE DEPARTING LOW. MID-LEVELS LAPSE
RATES SHOULD STEEPEN. LOOKING LIKE A CLOUDY COOL DAY WITH SCATTERED
SHOWERS AND THUNDERSTORMS THE BETTER CHANCES OF WHICH WILL BE ALONG
THE INVERTED TROUGH IN A REGION OF FAVORABLE LIFT AND INSTABILITY.
THAT AREA IS MAINLY ACROSS THE W-INTERIOR AND HUDSON RIVER VALLEY
REGION. ONSHORE E-FLOW WILL KEEP THE CENTRAL AND EASTERN FORECAST
AREA UNDER A MORE STABLE COOL AIRMASS THEREBY LIMITING ACTIVITY...
BUT NOT DOWN TO ZERO.
WITH ANY ACTIVITY...HEAVY RAIN AND GUSTY WINDS ARE POSSIBLE. WITH
THE DEEP-LAYER NNW FLOW ALONG THE INVERTED FRONT...STORMS MAY TRAIN
SO PERHAPS THERE IS A LOCALIZED FLOODING THREAT. THOUGH AGAIN...FEEL
THE BETTER CHANCES MAY REMAIN W OF NEW ENGLAND. WILL HAVE TO CLOSELY
WATCH OUT FOR IMPACTS ACROSS THE CT-RIVER VALLEY.
ACTIVITY CONCLUDES INTO EVENING. WILL HOLD WITH NEAR-SEASONABLE
TEMPERATURES OVER THE W AND CENTRAL INTERIOR OF NEW ENGLAND BUT
COOLER ALONG THE SHORES WITH ANTICIPATED SEA-BREEZE. ANTECEDENT
RAINS WITH LIGHT AND VARIABLE FLOW OVERNIGHT...IF CONDITIONS ARE
ALLOWED TO CLEAR OUT...THERE IS A GREATER PROPENSITY FOR DENSE FOG.
SUNDAY...
CONTINUED CYCLONIC FLOW BUT LESSER FORCING MECHANISMS. THE COLD POOL
LINGERS ALOFT CONTINUING THE PRESENCE OF STEEP MID-LVL LAPSE RATES.
AS THE BOUNDARY LAYER DESTABILIZES...EXPECT SHOWERS AND POSSIBLE
THUNDERSTORMS TO DEVELOP...BUT ON A MORE ISOLATED NATURE AND AGAIN
MAINLY ACROSS THE INTERIOR WITH THE LIKELIHOOD OF SEA-BREEZES ALONG
THE SHORES USHERING IN MORE STABLE AIR.
WILL PREVAIL WITH SEASONABLE TEMPERATURES. STORM MOTION SHOULD BE N
TO S. WITH ANY STORMS...HEAVY RAIN AND GUSTY WINDS ARE POSSIBLE. NO
CERTAINTY IN PINPOINTING WHERE AND WHEN STORMS WILL DEVELOP. WEATHER
SHOULD TURN QUIET OVERNIGHT AS DAYTIME HEATING CONCLUDES.
MONDAY...
WILL KEEP WITH A DRY FORECAST BUT WILL NEED TO MONITOR ADDITIONAL
ENERGY CYCLONICALLY DIGGING THROUGH THE PREVAILING TROUGH PATTERN
ACROSS N NEW ENGLAND. HAVE A FEELING THAT RIDGING WILL PREVAIL
BETWEEN THE DEPARTING WEEKEND DISTURBANCE AND THE EXPECTED DISTURBED
WEATHER FOR TUESDAY. THEREFORE...SUBSIDENCE PREVAILING WITH H85
TEMPERATURES AROUND +12C WILL YIELD WARM CONDITIONS WITH THE GREATER
CHANCE OF MOSTLY CLEAR CONDITIONS TO THE S AND W. THE SUBSEQUENT
BOUNDARY LAYER MIXING WILL YIELD BREEZY W-WINDS.
TUESDAY...
A FRONTAL DISTURBANCE WILL SWEEP ACROSS NEW ENGLAND FROM THE NW TO
SE. WILL SEE LIKELY SEE SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
PENDING ON THE TIMING OF THE DISTURBANCE WHICH IS KEY TOWARDS
WHETHER THE BOUNDARY LAYER WILL DESTABILIZE ALONG AND AHEAD. SIGNALS
HAVE BEEN CONSISTENT WITHIN THE MODELS AS TO OUTCOMES...YET WILL
EXERCISE CAUTION AND CONCLUDE IN DISCUSSION WITH THE SPREAD AND
VARIANCE OF OUTCOMES.
REST OF THE WEEK...
TOWARDS MIDWEEK AM EXPECTING A WARM-FRONT ALONG THE MID-LEVEL CLASH
OF AIRMASSES ALONG WHICH DISTURBANCES WILL TRAIN THROUGH THE
CYCLONIC FLOW POTENTIALLY PROVIDING PERIODS OF INCLEMENT WEATHER.
TOO MUCH SPREAD AS TO THE INFLUENCE OF RIDGING AGAINST THE LINGERING
TROUGH LENDS TO A LOT OF UNCERTAINTY. AGAIN...WILL PREVAIL TOWARDS
MODEL ENSEMBLE MEANS.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE.
THROUGH 00Z...VFR/MVFR CIGS WILL LOWER TOWARD EVENING. SHOWERS
WILL EXIT EASTERN MA 20-21Z. SCT SHOWERS DEVELOPING IN THE
INTERIOR. BRIEF MVFR VSBY IN SHOWERS.
TONIGHT...MODERATE CONFIDENCE. CIGS DETERIORATING THIS EVENING
WITH WIDESPREAD IFR DEVELOPING. AREAS OF FOG DEVELOPING WITH BEST
CHANCE OF DENSE FOG AND LIFR VSBYS ALONG THE COAST.
FRIDAY...IFR/LIFR IN THE MORNING SHOULD LIFT TO MVFR IN THE
INTERIOR...BUT IFR CIGS MAY PERSIST IN THE COASTAL PLAIN.
IMPROVING VSBYS. SCT SHOWERS AND ISOLD TSTMS POSSIBLE...HIGHEST
PROBABILITY IN WESTERN NEW ENG.
FRI NIGHT...WIDESPREAD IFR REDEVELOPING WITH AREAS OF FOG. SCT TO
NUMEROUS SHOWERS IN THE EVENING.
KBOS TAF...VFR CONDITIONS ARE TEMPORARY AND EXPECT IFR CIGS TO
REDEVELOP BY THIS EVENING WITH FOG DEVELOPING AS WELL. LOW
CONFIDENCE ON TIMING AND HOW LOW VSBYS WILL GET.
KBDL TAF...MODERATE CONFIDENCE IN TAF. CONDITIONS LOWERING TO
MVFR/IFR. LOW CONFIDENCE ON TIMING.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SATURDAY...MODERATE CONFIDENCE.
BKN LOW-END VFR CIGS. SCT -SHRA/TSRA THE BETTER CHANCE OF WHICH WILL
BE ACROSS W-INTERIOR NEW ENGLAND TOWARDS THE HUDSON RIVER VALLEY.
TEMPO IFR WITH TSRA WITH +RA AND GUSTY WINDS. SEA-BREEZES ALONG THE
SHORES. WITH ACTIVITY CLEARING OVERNIGHT...IF WINDS BECOME LIGHT...
DENSE IFR FOG POSSIBLE.
SUNDAY...MODERATE CONFIDENCE.
BKN LOW-END VFR CIGS. ISOLATED -SHRA/TSRA ACROSS INTERIOR NEW
ENGLAND. SEA-BREEZES ALONG THE SHORES. ACTIVITY CONCLUDES OVERNIGHT.
MONDAY...LOW CONFIDENCE.
WILL CONTINUE TO HOLD VFR WITH GUSTY W-WINDS UP TO AROUND 25 KTS.
TUESDAY...LOW CONFIDENCE.
CONDITIONS DETERIORATING BY MORNING. WIDESPREAD RAIN WITH EMBEDDED
HEAVIER SHRA AND POSSIBLE TSRA. WILL SEE A COLD FRONT SWEEP ACROSS
THE TERMINALS. TERMINALS BEGINNING TO IMPROVE W TO E BY EVENING.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE.
WINDS AND SEAS BELOW SCA THRESHOLDS THROUGH FRI EVENING WITH
EASTERLY FLOW. BUT CANT RULE OUT MARGINAL SCA CONDITIONS LATE FRI
NIGHT AS LOW LEVEL NE FLOW INCREASES AS LOW PRES PASSES TO THE
SOUTH. G20-25 KT AND 5 FT SEAS POSSIBLE FOR WATERS SE OF CAPE
COD.
THE MAIN CONCERN ON THE WATERS IS FOR AREAS OF
FOG WHICH COULD BE LOCALLY DENSE AT TIMES...PARTICULARLY DURING
THE LATE NIGHT/EARLY MORNING HOURS.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
WHILE DAILY OCCURRENCES OF SEA-BREEZES ALONG THE SHORES ARE TO BE
EXPECTED...WINDS OVERALL INITIALLY OUT OF THE NE WILL VEER OUT OF
THE SW WITH TIME. SEAS TO REMAIN BELOW 5 FEET. DENSE FOG WILL BE
POSSIBLE ACROSS THE WATERS SATURDAY NIGHT INTO SUNDAY MORNING
RESULTING IN SIGNIFICANT VISIBILITY RESTRICTIONS.
MONDAY...LOW CONFIDENCE.
W/SW WINDS WITH GUSTS UP TO 25 KTS. SEAS ON THE OUTER-WATERS
GETTING UP TO 5 FEET.
TUESDAY...LOW CONFIDENCE.
INCREASING RAIN CHANCES AS A FRONT SLIDES ACROSS THE WATERS LATE.
WILL SEE SW WINDS BACK OUT OF THE NW WITH FRONTAL PASSAGE. WAVES
GETTING UP TO 5 FEET ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
150 PM CDT THU MAY 22 2014
.DISCUSSION...
1158 AM CDT
MAIN UPDATES THIS MORNING WERE TO INCREASE CLOUD COVER...AND MAKE
MINOR ADJUSTMENTS TO TEMP TRENDS.
LATEST SATELLITE IMAGERY DEPICTING RAPIDLY WEAKENING SYSTEM MOVING
EAST INTO WESTERN ILLINOIS AT THIS TIME. ALTHOUGH
WEAKENING...STILL PROVIDING EXPANSIVE AND DENSE CLOUD SHIELD
ACROSS THE REGION. PREVIOUS FORECAST WAS ON TRACK WITH INCREASING
CLOUD COVER THROUGH MID DAY...BUT DID INCREASE SLIGHTLY MORE MAINLY
ACROSS THE SOUTHERN CWA WHERE A PERIOD OF MOSTLY CLOUD SKIES WILL
BE OBSERVED. EXPECT THIS CLOUD SHIELD TO THIN THROUGH MID
AFTERNOON WITH A RETURN TO MORE SUNNY SKIES BEFORE SUNSET.
OUTSIDE OF TEMPS NEAR THE LAKE...CURRENT FORECAST HIGH TEMPS OF
LOWER 70S STILL ON TRACK. PERSISTENT ONSHORE FLOW KEEPING AREAS
NEAR THE LAKE RATHER COOL...WITH UPPER 50S CURRENTLY BEING
REPORTED. DID ADJUST TEMP TRENDS INTO THE AFTERNOON...AND FEEL
THAT MOST LOCATIONS NEAR THE LAKE WILL STRUGGLE TO RISE MUCH FROM
THE UPPER 50S/AROUND 60 THIS AFTERNOON.
RODRIGUEZ
//PREV DISCUSSION...
306 AM CDT
A QUIET END TO THIS WEEK OFFERS MAINLY ONLY TEMPERATURE FORECAST
CHALLENGES. WHILE THERE ARE SMALL CHANCES OF THUNDERSTORMS FORECAST
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK...THE REGIME FORECAST IS
ONE THAT KEEPS THE PROBABILITY LOW OF ANY HIGH IMPACT WEATHER THROUGH
THE HOLIDAY.
TODAY...
AN UPPER LOW ACROSS EASTERN ONTARIO THIS MORNING WILL CONTINUE TO
USHER A SURFACE COLD FRONT SOUTH FROM CENTRAL ILLINOIS AND INDIANA
TODAY. DAMPENED UPPER RIDGING WILL REMAIN IN PLACE FROM THE SOUTHERN
U.S. THROUGH THE MISSOURI RIVER VALLEY TODAY. WITH A STRONG UPPER
JET BETWEEN THESE TWO UPPER FEATURES...BROAD WEAK ASCENT WITHIN THE
RIGHT ENTRANCE REGION AND A SHEARED SHORT WAVE SHOULD SUPPORT HIGH
CLOUDS TO SPREAD ACROSS THE FORECAST AREA LATE THIS MORNING INTO THE
AFTERNOON. THIS IS LIKELY TO BE THICKER IN THE SOUTHERN FORECAST
AREA AND HAVE INCREASED FORECAST CLOUD COVER MORE SO THERE...BUT AT
LEAST SOME AREA WIDE. TEMPERATURES WILL LIKELY BE EFFECTED SLIGHTLY
BY THIS...ALTHOUGH COOLING WITHIN/AT THE TOP OF THE MIXED LAYER FROM
YESTERDAY WILL BE THE PRIMARY REASON FOR COOLER HIGHS. ONSHORE FLOW
WILL DEVELOP BY MID-MORNING WITH COOLER TEMPERATURES NEAR THE LAKE.
EXPECT THAT THE THERMAL DIFFERENCE BETWEEN DOWNTOWN CHICAGO AND FAR
WESTERN SUBURBS TO BE 10-12 DEGREES...NEAR THE LATE MAY CLIMO NORMAL
WITH ONSHORE FLOW ALL DAY.
TONIGHT THROUGH FRIDAY NIGHT...
A SURFACE HIGH WILL CENTER OVER THE AREA OFFERING LIGHT WIND FLOW.
BY LATE THIS EVENING AND THROUGH THIS PERIOD THERE LOOKS TO BE
LITTLE IN THE WAY OF CLOUDS. ONSHORE FLOW WILL REDEVELOP DURING
FRIDAY KEEPING LAKESIDE AREAS IN THE LOWER 60S OR SO. BOTH NIGHTS
LOOK TO SUPPORT 40S FOR LATE NIGHT LOWS IN THE MOST AREAS...WITH
SOME OF THE COOLER SPOTS REALIZING LOWER 40S ON FRIDAY NIGHT.
THE HOLIDAY WEEKEND INTO NEXT WEEK...
THE MEANDERING UPPER LOW ACROSS THE SOUTHWEST U.S. WILL DRIFT
NORTHEAST AS A RESULT OF BEING DISJOINTED FROM THE STRONGER WESTERLY
JET ACROSS THE U.S./CANADIAN BORDER. SUCH A CLOSED FEATURE IN THAT
PATTERN SEEMS TO MORE OFTEN THAN NOT MOVE SLOWER THAN INITIALLY
DEPICTED BY LONG RANGE GUIDANCE. WARM ADVECTION AND PRECIPITABLE
WATER INCREASE ARE FORECAST TO OCCUR SUNDAY AND MOST DETERMINISTIC
AND ENSEMBLE GUIDANCE HINT AT SOME CHANCE OF PRECIPITATION IN THE
REGION...THOUGH MAINLY NORTHWEST OF THE AREA. THE UPPER RIDGE IS
FORECAST TO RE-AMPLIFY OVER THE AREA ON THE HOLIDAY WITH A WEAK
SURFACE FRONT TO THE NORTH. IF THAT PATTERN WERE TO UNFOLD...THUNDER
CHANCES LOOK MINIMAL OVER THE FORECAST AREA. HAVE DECREASED THE
COVERAGE AND MAGNITUDE OF POPS PROVIDED BY A MODEL/PREVIOUS FORECAST
BLEND FOR THE HOLIDAY AND TUESDAY. THE UPPER LOW OR OPEN WAVE SHOULD
SHIFT EAST DURING THE MIDDLE OF THE WEEK...THOUGH THE 22.00 GFS
ACTUALLY TURNS THIS SOUTHEAST WITH BASICALLY VERY LITTLE PRECIP
CHANCES DURING MIDWEEK. WHILE THAT SEEMS A LITTLE SUSPECT...THE
CHANCES FOR RAIN LOOK SMALL AT THIS DISTANCE.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NELY-ELY WINDS WITH SUSTAINED SPEEDS LESS THAN 10 KT...BECOMING
LGT/VRBL AT SUNSET.
* NORTHEAST WINDS LESS THAN 10 KT FRIDAY.
KREIN
//DISCUSSION...UPDATED 18Z...
WINDS WILL BE THE PRIMARY CONCERN FOR THE NEXT 24-36 HOURS. WITH
HIGH PRESSURE EXTENDING OVER THE UPPER MISSOURI VALLEY AND LOW
PRESSURE OVER NEW ENGLAND...WINDS OVER THE REGION HAVE BECOME
GENERALLY NORTHWESTERLY AND LIGHT. HOWEVER...THE WEAK GRADIENT AND
LARGE TEMPERATURE DIFFERENCE BETWEEN THE COLD LAKE MICHIGAN WATER
AND LAND HAS SET UP A LAKE BREEZE WHICH HAS ALREADY PUSHED THROUGH
ORD/MDW/GYY...TURNING WINDS ELY AT ORD/MDW AND NLY AT GYY. DPA/RFD
SHOULD NOT BE AFFECTED AND WINDS WILL REMAIN MORE REFLECTIVE OF
THE SYNOPTIC PATTERN. THROUGH THE EVENING...THE HIGH WILL MOVE
ACROSS THE TERMINAL AREAS AND WINDS SHOULD BECOME LGT/VRBL. BY
TOMORROW MORNING...WITH THE HIGH PUSHING OVER THE WESTERN GREAT
LAKES REGION...WINDS WILL BECOME SYNOPTICALLY NORTHEASTERLY...SO
ANY LAKE EFFECT WILL BE NEGLIGIBLE. SUSTAINED WIND SPEEDS SHOULD
INCREASE THROUGH THE MORNING...BUT GENERALLY REMAIN LESS THAN
10KT.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR. EARLY EVE NORTHEAST WINDS LIKELY BECOME LIGHT/VRB.
SATURDAY...VFR. EASTERLY WINDS THROUGH EVENING.
SUNDAY...SCHC TSRA...OTHERWISE MAINLY VFR.
MONDAY...CHC TSRA...OTHERWISE MAINLY VFR.
TUESDAY...SCHC TSRA...OTHERWISE MAINLY VFR. NE WIND SHIFT PSBL.
WEDNESDAY...CHC TSRA. NORTHEAST WINDS PSBL.
RC
&&
.MARINE...
148 PM CDT
A LARGE AREA OF HIGH PRESSURE...CURRENTLY CENTERED ACROSS THE UPPER
MIDWEST...WILL GRADUALLY SHIFT EASTWARD OVER LAKE MICHIGAN BY LATE
FRIDAY INTO SATURDAY. THIS WILL RESULT IN FAIRLY LIGHT WINDS ACROSS
THE LAKE...WITH LAKE BREEZE INFLUENCES LIKELY TO PRODUCE ONSHORE
FLOW DURING THE DAYS FRIDAY AND SATURDAY. ONCE THE HIGH SHIFTS EAST
OF THE LAKE ON SUNDAY...EXPECT THE WINDS TO SHIFT BACK OUT OF THE
SOUTH INTO EARLY NEXT WEEK. WIND SPEEDS MAY INCREASE UP TO AROUND 20
KT OR SO FOR A PERIOD INTO MONDAY AS IT APPEARS THE PRESSURE
GRADIENT WILL STRENGTHEN IN RESPONSE TO A TOUGH OF LOW PRESSURE
POSSIBLY TRACKING ACROSS WESTERN ONTARIO AND THE UPPER MIDWEST. THIS
SYSTEM LOOKS TO ALSO INCREASE THE CHANCES OF MORE SHOWER AND
THUNDERSTORM ACTIVITY OVER THE LAKE LATER SUNDAY NIGHT AND MONDAY.
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:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1250 PM CDT Thu May 22 2014
.DISCUSSION...
ISSUED 1046 AM CDT Thu May 22 2014
High pressure building back into the region and a more stable
airmass dominating. MCS remnants to the west running into a drier
airmass as well and precip is dwindling as it crosses the
Mississippi River. Expect the trend to continue. Keeping the
forecast mainly dry with a slight chance mention for the west this
afternoon, though a stray sprinkle or two may remain possible
through the late morning hours. Forecast temperatures are on track
under mostly cloudy skies as plenty of mid clouds stream into the
FA remnants of the MCS. No updates are anticipated at this time.
&&
.AVIATION...
ISSUED 1246 PM CDT Thu May 22 2014
Not much of a shift in the forecast. VFR throughout. Decaying MCS
to the west bringing in a chance for maybe VCSH in PIA but keeping
predominant precip out for now. Lightning activity is to the west
and expected to propagate to the SE, missing ILX terminals.
Some AC out there in addition to some cirrus keeping decks well
within VFR conditions. Northerly winds pick up a more NErly fetch
in the overnight hours and sct high clouds continue through
morning.
HJS
&&
.PREV DISCUSSION...
ISSUED 319 AM CDT Thu May 22 2014
SHORT TERM...Today through Saturday
07z/2am surface analysis shows cold front extending from near
Paris to just south of Taylorville. Ahead of the boundary, a
warm/humid airmass persists across southeast Illinois where
dewpoints are in the middle to upper 60s. Meanwhile behind the
front, northerly winds have brought considerably drier air into
much of central Illinois, with dewpoints dropping into the upper
40s and lower 50s north of I-72. Front will continue to sag
southward today, eventually dropping south of the Ohio River by
late afternoon. As a result, cooler and less humid conditions can
be expected with high temps remaining in the 70s. Precip chances
will develop along/ahead of the front this afternoon, but will
remain south of the KILX CWA. The only potential fly in the
ointment will be a weak short-wave currently tracking out of
Colorado. As this feature approaches from the west, a few
showers/storms may spread into the far W/SW CWA this afternoon and
evening. While most models keep central Illinois completely dry
today and tonight, higher-res models such as the RAP and HRRR show
precip associated with the wave moving across central/southern
Iowa and approaching from the west this afternoon. Have therefore
included a slight chance POP along/southwest of a Rushville to
Jacksonville line this afternoon into tonight.
High pressure will build into the southern Great Lakes by the end
of the week, pushing the front even further south/southwest. With
dry N/NE flow around the high, sunny skies will be the rule on
both Friday and Saturday with temperatures in the 70s and low
relative humidity values.
LONG TERM...Sunday through Wednesday
As high slides off to the east, remnants of old frontal boundary
will return northward on Sunday. Models continue to produce some
QPF across the area as the warmer air returns: however, with only
meager forcing along a dissipating boundary and rising upper heights,
think this is overdone. Upper ridge will build in earnest across
the Midwest early next week, leading to temperatures climbing well
into the 80s. Big question will be how fast the ridge breaks down
as cut-off low currently over southern California works its way
eastward. GFS has been the slowest model with this process for the
past few runs and its 00z May 22 solution is no exception.
Meanwhile, ECMWF had previously been faster, but its latest run
has slowed down and now keeps wave west of Illinois until
Wednesday. Given high-amplitude upper ridge in place over the
Midwest, continue to favor a slower solution. Even though both the
GFS and ECMWF delay the arrival of the upper low until mid-week,
both produce QPF across the area on Monday and Tuesday. Given high
upper heights and lack of forcing, think little more than isolated
diurnal convection will fire on either of those two days. As such,
have kept the forecast dry until Wednesday when better forcing
arrives with the approaching upper low.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
557 PM CDT Thu May 22 2014
...Updated for the aviation discussion...
.SHORT TERM...(This evening through Friday)
ISSUED AT 346 PM CDT THU MAY 22 2014
Tonight:
Main concern is dealing with orographic convection to the west. Afternoon
radar mosaic shows considerable thunderstorm activity across Colorado
and New Mexico. MCS propagation vectors support the eastward translation
of this activity and will eventually reach far SW Kansas by evening.
The HRRR is insistent in generating an MCS with a cold pool. This model
does seem to be - at times- too aggressive with cold pool generation.
Still, enough isentropic lift and moisture advection supports ramping
up the pops this evening. Think the main concern is heavy rainfall as
the 12Z KDDC raob PWAT is between the 75th percentile and the +2SD mark.
This is statistically significant. Bulk shear is far from reaching supercell
archetype. Secondary threat to heavy rainfall is outflow winds, which
could impact far western Kansas along and west of Highway 83. The boundary
layer will become more stable this evening, so that could mitigate any
momentum transfer issues. In addition to convection, have increased
QPF more in line with WPC guidance. Most of the mesoscale models (HRRR/WRF/4
km NAM) all suggest that a good chunk of the region might see 0.50-1.00"
from tonights and tomorrow thunderstorm activity.
Tomorrow:
Have ramped up pops again by afternoon and evening as PWAT remains near
an 1.00" and isentropic lift/warm air advection continues through the
day. Moist adiabatic thermodynamic skew-t/log-p`s and also slow MCS
propagation vectors suggest that heavy rainfall is still a threat for
tomorrow. Highest pops will be during the afternoon to 00Z as diurnally
induced instability increases. Again, would not be surprised to see
decent rainfall amounts through 7 pm tomorrow night, as alluded to
above.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 235 PM CDT THU MAY 22 2014
Medium range models indicate a southwest flow aloft prevailing
across the Western High Plains Saturday as a closed off upper level
low shifts slowly eastward across the Four Corners Region. As the
system approaches, increased divergence aloft downstream of the
trough axis will intensify across the high plains of eastern
Colorado, western Kansas, and the panhandle of Oklahoma, especially
into Saturday evening. Meanwhile, a prevailing low level
south-southeasterly flow will continue to draw additional moisture
into the state with H85 dewpoints nearing 15C. Although the flow
aloft is expected to remain generally weak, GFS/ECMWF model
soundings do show some marginal directional shear along with SBCAPE
values in excess of 1500 J/KG. As H5 vort maxima cycle northeast out
of the trough axis into the high plains, shower and thunderstorm
development is likely with some chance for marginally severe
weather possible. However, a bigger concern may be the potential
for brief periods of heavy rainfall with model soundings also
showing PW values well over one inch.
Similar conditions will exist Sunday as the closed off upper level
low moves across the Rockies into the Western High Plains. However,
a few more thunderstorms may be possible as an upper level jet noses
northward into southwest Kansas Sunday afternoon while a developing
dryline sharpens near the Colorado border. In addition, GFS/ECMWF
model soundings indicate an inverted V profile by Sunday afternoon
with SBCAPE values pushing above 2000 J/KG. Although speed shear
looks a little more favorable than Saturday, directional shear
does not which may limit the strength of any developing storms.
However, the potential for significant rainfall lingers with PW
values remaining fairly high with values near to a little above
one inch. Shower and thunderstorm potential shifts eastward more
into central Kansas Monday as the closed off low pushes further
east into western Kansas. Drier conditions are likely by Wednesday
as weak upper level ridging fills in across the Western High
Plains in wake of the departing upper level low.
Fairly mild temperatures are likely Saturday as a cooler air mass
remains locked in across the Western High Plains The GFS/ECMWF show
H85 temperatures changing little from Friday with the mid teens(C)
across central Kansas to the upper teens(C) out near the Colorado
border. Due to expected increased cloud cover and areas of precip,
look for highs up into the upper 70s(F) to near 80F. Similar
temperatures are likely into Monday before a gradual warming
trend begins by mid week as weak upper level ridging develops
across the Intermountain West.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 552 PM CDT THU MAY 22 2014
There is a large upper level wave moving east through southwestern
Kansas. This will being thunderstorms first to GCK by 02Z, DDC by
04Z and not to HYS until 08-09Z. Cigs with the thunderstorm
passage will be MVFR in the OVC040 range, but winds may gust near
the thunderstorms in the 20g35kt range. The convection will pass
and VFR conditions will return towards 10 to 11Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 63 79 61 80 / 70 60 60 60
GCK 61 78 60 81 / 70 60 60 60
EHA 59 76 59 80 / 70 40 50 60
LBL 61 76 61 81 / 70 60 60 60
HYS 62 78 62 80 / 40 60 60 50
P28 66 80 64 82 / 40 60 60 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sugden
LONG TERM...JJohnson
AVIATION...Burke
AREA FORECAST DISCUSSION
NWS GOODLAND KS
328 PM MDT THU MAY 22 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 148 PM MDT THU MAY 22 2014
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS LARGE CLOSED UPPER OVER
SOUTHERN CALIFORNIA WITH RIDGE ACROSS PLAINS AND SOUTHEASTERN US.
SOUTHERLY/DIFLUENT FLOW IS IN PLACE ACROSS THE SOUTHERN PLAINS AND
ROCKIES WITH MOIST PLUME EXTENDING FROM PACIFIC NORTH WITHIN THIS
FLOW. AT THE SURFACE A STALLED FRONT IS ANALYZED ACROSS SOUTHERN KS
AND ACROSS OK/TX PANHANDLES. UPSTREAM RADARS SHOW THUNDERSTORM
ACTIVITY ALREADY DEVELOPING ACROSS NORTHEAST NEW MEXICO AND ALONG
THE FRONT RANG WITH A NORTHERLY PROGRESSION.
UPPER LEVEL ENERGY ROTATING THROUGH THE UPPER FLOW ON THE EASTERN
EDGE OF THE UPPER TROUGH WE WILL CONTINUE TO SUPPORT
SHOWER/THUNDERSTORM DEVELOPMENT. ANOMALOUSLY MOIST AIR MASS (PWATS
TWO STANDARD DEVIATIONS ABOVE NORMAL) WILL LINGER TONIGHT THROUGH
TOMORROW.
FOR TONIGHT...THUNDERSTORMS ARE DEVELOPING IN PROXIMITY TO LARGE
SCALE DIFLUENT FLOW OVER NEW MEXICO AND CENTRAL COLORADO. TD VALUES
AROUND 60F HAS LEAD TO SBCAPE 1500-2000 J/KG. GUIDANCE SHOWS MUCAPE
THROUGH FRIDAY AROUND 2000 J/KG OVER OUR CWA. GUIDANCE SUPPORTS
THUNDERSTORM ACTIVITY UPSTREAM FROM OUR CWA MERGING INTO
CLUSTER/THUNDERSTORM COMPLEX AND SPREADING NORTH INTO OUR CWA. WITH
ELEVATED FRONTAL ZONE GENERALLY LINGERING NEAR THE I-70 CORRIDOR AND
MOISTURE POOLING/INSTABILITY LINGERING WE SHOULD SEE A GOOD PATTERN
FOR THIS ACTIVITY INCREASING IN COVERAGE. 0-6KM WIND IS 15KT OR
LESS...HOWEVER WIND PROFILES BELOW 800MB ARE VERY WEAK ALONG FRONTAL
ZONE OUT OF THE EAST...WHILE 400-250MB WINDS ARE STRAIGHT OUT OF THE
WEST. IN ADDITION TO THE ALREADY WET SIGNAL THIS PATTERN SUPPORTS
BACK BUILDING OF THUNDERSTORMS ALONG FRONTAL ZONE AND VERY SLOW
PROPAGATION OF THUNDERSTORMS. CONFIDENCE IS INCREASING IN AT LEAST A
LOCALIZED FLOODING THREAT TONIGHT...BUT I AM NOT SURE HOW WIDESPREAD
THIS WILL BE SO I AM HOLDING OFF ON ISSUANCE OF FLASH FLOOD WATCH.
SHEER PROFILES ARE NOT THAT IMPRESSIVE...HOWEVER WITH MODERATE
INSTABILITY/GOOD MID LEVEL LAPSE RATES...DAMAGING WINDS ASSOCIATED
WITH COLD POOL DRIVEN THUNDERSTORM COMPLEXES OR STRONG WIND/LARGE
HAIL WITH PULSE TYPE CONVECTION CANT BE RULED OUT.
GUIDANCE SHOWS GOOD 850MB SUPPORT LINGERING OVERNIGHT AND MODELS
CONTINUE TO LINGER SHOWERS/THUNDERSTORMS THROUGH TOMORROW
AFTERNOON...WITH AN ENHANCEMENT IN ACTIVITY AS SURFACE FRONT STALLS
ALONG KS/NE STATE LINE. I WAS COMFORTABLE LINGERING POPS ACROSS THE
CWA THROUGH THE SHORT TERM PERIOD...THOUGH I DID TRY TO TIME OUT THE
PERIODS BETWEEN WEAK SHORTWAVES FOR POSSIBLE LULLS IN COVERAGE. I
ALSO BUMPED UP QPF TO REFLECT PERIODS OF MODERATE-HEAVY PRECIP
POTENTIAL. THERE IS ALSO SOME POTENTIAL FOR FOG DEVELOPMENT LATE
TONIGHT/EARLY FRIDAY...HOWEVER SURFACE PATTERN COULD BE CHAOTIC IF
THUNDERSTORM ACTIVITY IS ONGOING...AND DECIDED NOT TO INCLUDE
MENTION WITH THIS UPDATE. TEMPS TONIGHT AND FRIDAY ARE TRICKY AS
MODELS WOULD SUPPORT SHOWERS/THUNDERSTORMS ACROSS THE REGION THROUGH
THESE PERIODS...AND FRONTAL POSITION IS STILL UNCERTAIN.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 328 PM MDT THU MAY 22 2014
MAIN FORECAST CONCERNS HOW LONG WILL UPCOMING WET PERIOD LAST AND
HOW MUCH WE WILL GET DURING THIS TIME WHICH LEAD TO HYDRO ISSUES.
SATELLITE SHOWING AN AMPLIFIED PATTERN FROM THE PACIFIC INTO NORTH
AMERICA. FOR OUR AREA SITUATION FOR THE FORESEEABLE FUTURE WILL BE
CONTROLLED BY SPEED AND LOCATION OF UPPER LOW NOW CUTTING OVER THE
SOUTHWEST PORTION OF THE COUNTRY. FLOW BEHIND THIS SYSTEM ALONG
WITH STRONGER JET WINDS AND HEIGHT FALLS TO ITS SOUTH SHOWING SLOW
MOVEMENT AND A FURTHER SOUTH MOVEMENT WILL CONTINUE. STATIONARY
FRONT CONTINUES TO BE TO OUR SOUTH AND WEST WITH THE SOUTHERN
POSITION ROUGHLY ALONG THE KANSAS BORDER.
AT JET LEVEL...MODELS APPEARED TO DO FINE. AT MID LEVELS...THE
MODELS TENDED TO BE TOO FAR SOUTH AND EAST WITH THE SOUTHWEST UPPER
LOW. HERE AND OVERALL THE UKMET WAS DOING A LITTLE BETTER THAN THE
GFS AND CANADIAN. THE NAM WAS DOING A LITTLE BETTER THAN THE ECMWF
ON THE SURFACE WIND AND PRESSURE FIELD. THE GFS WAS DOING A LITTLE
BETTER THAN THE CANADIAN AND SREF ON THE LOW LEVEL THERMAL FIELD.
FRIDAY NIGHT...CONTINUATION OF WHAT IS STARTING DURING THE DAY.
LARGE AREA OF THUNDERSTORMS/HEAVY RAINFALL MOVES ACROSS THE AREA
FROM SOUTHWEST TO NORTHEAST. IT LOOKS LIKE THERE SHOULD BE A LULL IN
THE PRECIPITATION TOWARD THE END OF THE NIGHT. AT THAT TIME...MODELS
ARE SHOWING A NEARLY SATURATED BOUNDARY LAYER AIR MASS. IF NO
RAINFALL IS OCCURRING THERE LOOKS LIKE THERE WILL BE A GOOD CHANCE
OF AREAS OF FOG DEVELOPING.
SATURDAY/SATURDAY NIGHT...AFTER OVERNIGHT SHORTWAVE TROUGH MOVES
THROUGH THE MID LEVELS DRY OUT AND SHOULD HAVE A BRIEF TIME PERIOD
WHERE LITTLE TO NO PRECIPITATION SHOULD BE OCCURRING. AREAS OF FOG
SHOULD CONTINUE THROUGH THE MORNING. MODELS ARE IN GENERAL
AGREEMENT OF HAVING THE UPPER LOW NEAR THE ARIZONA/NEW MEXICO
BORDER BY LATE IN THE AFTERNOON. ANOTHER SHORTWAVE ROTATES IN FROM
THE SOUTH AS DIFLUENT FLOW ALOFT MOVES OVER THE AREA. MODELS ARE
TRYING TO DRY OUT THE AIR MASS WITH THIS FLOW IN PLACE AND AM NOT
BUYING THIS RIGHT NOW. SHOULD BE ANOTHER ROUND OF THUNDERSTORMS
WITH MODERATE TO HEAVY RAINFALL.
SUNDAY...SOME DIFFERENCE ON POSITION OF THE UPPER LOW IS SHOWN BY
THE ENSEMBLES AND DETERMINISTIC MODELS WHICH AFFECTS MANY THINGS BUT
UPPER JET LOOKS TO BE NEAR OR OVER THE WESTERN HALF OF THE AREA.
AREA IS STILL IN SOUTHERLY FLOW ALOFT WITH LOW LEVEL ALSO
CONTINUING TO BRING IN MOISTURE. A SHORTWAVE ROTATES THROUGH THIS
WHILE A UPPER JET AXIS ESTABLISHES ITSELF OVER THE WESTERN HALF OF
THE AREA. ONCE AGAIN MODELS ARE SHOWING THE AIR MASS DRYING AND AM
NOT SURE ABOUT THAT. THERE SHOULD BE A CONTINUED CHANCE OF
THUNDERSTORMS.
SUNDAY NIGHT THROUGH THURSDAY...MODEL HANDLING OF UPPER LOW BY
ENSEMBLES AND DETERMINISTIC OUTPUT ARE SHOWING DIFFERENCES. ALTHOUGH
THERE IS A GENERAL TENDENCY OF SLOWING THE LOW OR KEEPING IT NEARLY
STATIONARY SUNDAY NIGHT INTO MONDAY WITH A BETTER AGREEMENT IN
HAVING THE CIRCULATION FURTHER SOUTH. MODELS ACTUALLY TAKE THIS
SYSTEM THROUGH MONDAY INTO MONDAY NIGHT IN A FAVORABLE POSITION TO
BE IN WRAP AROUND/MID LEVEL DEFORMATION ZONE. ALL THESE DIFFERENCES
NOT SURPRISING WITH THIS SINCE MODELS USUALLY DO HAVE A PROBLEM WITH
THESE KIND OF SYSTEMS AND THIS IS RATHER UNUSUAL FOR THIS TIME OF
YEAR.
THE CRH_INIT GAVE ME CHANCE POPS SUNDAY NIGHT INTO MONDAY WITH
SLIGHT CHANCES GIVEN MONDAY NIGHT. AM CONCERNED THAT THIS PERIOD
COULD END UP BEING WETTER...ESPECIALLY MONDAY AND MONDAY NIGHT. AM
CONTENT RIGHT NOW IN LEAVING THIS AS IS SINCE THERE ARE HIGH CHANCE
POPS IN THERE. WITH THAT MONDAY HIGH TEMPERATURES COULD BE COOLER
AND OVERALL MAY NOT BE THE MOST PLEASANT MEMORIAL DAY. BY THE TIME
MONDAY ENDS...A SUBSTANTIAL AMOUNT OF PRECIPITATION SINCE TODAY
COULD HAVE OCCURRED AND MAY BE EXPERIENCING HYDRO PROBLEMS THROUGH
MOST OF THIS PERIOD.
ON TUESDAY...MODELS STILL NOT SHOWING THE SYSTEM NOT TOO FAR TO THE
EAST AND SOUTH AT THE BEGINNING OF THE DAY. THIS DAY COULD DEFINITELY
BE COOLER AND WETTER AS WELL BUT EVERYONE IS CONTENT IN LEAVING AS IS
AND DO NOT BLAME THEM WITH THE MODEL DIFFERENCES. THERE IS SOME
MOVEMENT TO THE SOUTH AND EAST THROUGH TUESDAY NIGHT.
PROBABLY THE MOST UNCERTAIN TIME PERIOD IS WEDNESDAY INTO THURSDAY.
THE ECMWF AND GFS MOVE THE SYSTEM ABOUT THE SAME AMOUNT TO THE
EAST. HOWEVER...THE GFS IS FURTHER SOUTH. THE GFS HAS MORE RIDGING
OVER OUR AREA THAN THE ECMWF. THE ECMWF EVEN STARTS TO RETROGRADE
THE SYSTEM A LITTLE DURING THIS TIME PERIOD. THE AIR MASS STILL LOOKS
MOIST ENOUGH TO SUPPORT CONVECTION WITH SOME SHORTWAVE TROUGHS MOVING
THROUGH WITH THE ECMWF LOOKING A LITTLE MORE FAVORABLE. CRH_INIT
DOES HAVE SOME LOW CHANCE POPS IN THERE FROM LATE WEDNESDAY INTO
THURSDAY. THIS MAY BE A BIT WET BUT THIS IS CONVECTIVE SEASON AND
THESE POPS ACTUALLY FIT CLIMATOLOGY. SO NOT ONLY DID I NOT CHANGE
ANY OF THE POPS BUT OVERALL CHANGED NOTHING ELSE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1122 AM MDT THU MAY 22 2014
THROUGH THE FIRST 12HR OF THE TAF PERIOD THE PRIMARY AVIATION
CONCERN WILL THE THUNDERSTORM ACTIVITY EXPECTED TO DEVELOP THIS
AFTERNOON AND SPREAD NORTHEAST OVER BOTH TERMINALS. BEST COVERAGE
WILL BE LATE AFTERNOON THROUGH THE LATE NIGHT TONIGHT
PERIOD...WITH SCATTERED SHOWERS/ISO THUNDER THEN LINGERING THROUGH
THE REST OF THE TAF PERIOD. WILL NEED TO MONITOR RADAR TRENDS AND
INTENSITY IN THE EVENT TEMPORARY IFR/MVFR CONDITIONS DEVELOP WITH
THUNDERSTORM ACTIVITY. AS THIS ACTIVITY IS WINDING DOWN MOISTURE
POOLING ALONG FRONTAL ZONE MAY LEAD TO FOG AND LOW STRATUS
DEVELOPMENT ALONG THE INTERSTATE 70 CORRIDOR...WITH LIFR CONDITIONS
POSSIBLE BY 12Z AT KGLD (AS INDICATED BY SOME GUIDANCE). IT IS WAY
TOO UNCERTAIN AT THIS POINT CONSIDERING THUNDERSTORM ACTIVITY
COULD COMPLICATE SURFACE PATTERN...AND THUS THE POTENTIAL FOR FOG.
FOR NOW I HAVE ONLY MENTIONED 3SM BR AROUND 12Z AT KGLD TO ACCOUNT
FOR THIS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
351 PM CDT Thu May 22 2014
.SHORT TERM...(This Evening through Friday)
Issued at 350 PM CDT THU MAY 22 2014
A broad closed upper low was located across southern CA this
afternoon. A minor H5 shortwave trough was lifting northeast across
south central KS and was providing enough ascent for an area of
showers and thunderstorms across east central and central KS.
At the surface an outflow boundary extended from near Fort Scott,
KS, then extended west-northwest to near Cassoday before extending
southwest, east of ICT into northwest OK. The 19Z SPC mesoscale
EMC RUC showed 1500 ML CAPE along and south of the OFB across south
central and southeast KS. The instability decreases across east
central and northeast KS, with MLCAPES less than 500 J/KG along and
north of I-70. The greatest chance for stronger storms this
afternoon and early evening will be along and south of I-35, where
the stronger thunderstorms may produce pea to penny size hail and
wind gusts of 40 to 50 MPH. Across the remainder of east central KS
the greatest hazard will be brief heavy rainfall.
Tonight, once the minor H5 trough lifts northeast into northern MO,
the thunderstorms will push east of the CWA. Thunderstorms
developing across eastern CO late this afternoon will congeal into
one or two complexes of thunderstorms and track east and southeast
across western KS during the evening hours and may move into north
central KS after midnight, then across portions of east central KS
through the early morning hours of Friday. At this time the best
rain chances late tonight will be along and south of a Concordia, to
Manhattan, to Ottawa line, but this will be more of mesoscale
forecast and will depend on where the thunderstorms complexes
develop and how they will track during the evening hours. The
primary hazards from the thunderstorms later tonight will be pea to
penny size hail with locally heavy rainfall.
Friday...after the morning complex of thunderstorms weakens and
shifts east of the CWA, additional thunderstorms will redevelop
along the leftover outflow boundaries during the afternoon hours.
The effective shear looks to be rather weak, so any thunderstorms
that develop across northeast KS Tuesday afternoon should be pulse
storms with the primary hazard being small hail, gusty winds and
brief heavy rainfall. The best chances for thunderstorms Friday
afternoon will occur across the western and southern counties,
closer to the surface outflow boundary/front. Highs on Friday will
be in the mid to upper 70s.
.LONG TERM...(Friday Night through Thursday)
Issued at 350 PM CDT THU MAY 22 2014
The extended forecast will be noted with several chances for showers
and thunderstorms as a very slow-moving system moves through the
region.
By Friday night, models are in very good agreement in having a
closed-off low anchored over the southwestern U.S. and slowly
progress east-northeastward toward the region through the weekend.
As a result, southwesterly flow aloft will prevail with ample
moisture surging into the area. There looks to be a decent chance
for showers and thunderstorms Friday night into Saturday evening as models
suggest a shortwave developing along the lee side of the mid-level
trough and tracking into the area. While models suggest MUCAPE
values could be upwards of 1000-1500 J/kg, 0-6km bulk shear values
continue to look extremely low at less than 20kts. As a result, the
probability of severe weather still looks to be very low, however
cannot completely rule out the slight chance for small hail or some
stronger winds from any stronger storms that develop. The main
concern with this activity will be for heavy rainfall as soundings
show a very deep moist adiabatic profile with PWAT values upwards of
1.50 to 1.75 inches. If these rounds of showers and thunderstorms
end up tracking over the same areas, then we could see some
localized flash flooding.
By the latter part of the weekend into next week, the models
certainly begin to struggle in handling the details of this
approaching system. With that in mind, some models are suggesting
that the region may be between shortwaves Sunday and Sunday night,
so precipitation chances are lower during this period with any
activity likely being more scattered in nature. On Monday, the
mid-level low should be progressing towards western Kansas and the
Texas/Oklahoma panhandles. There looks to be a decent chance for
showers and thunderstorms on Monday as another shortwave tracks near
the area. Beyond Monday, as previously mentioned, the models
struggle with the tracking and timing of any additional shortwaves
as the mid-level low finally tracks over or just south of the area
Tuesday night through Wednesday. Additionally, there are very
notable differences in the tracking of the center of this low, as
the ECMWF keeps it just south of the forecast area with the GFS
having it dive much further south. Due to the large model
uncertainty, made only minor adjustments to the consensus forecast
with slight to low-end chance PoPs in place Monday night through
Wednesday night. The potential for severe storms next week continues
to be low.
Between the prolonged period of cloud cover and not much in the way
of temperature advection, expect temperatures to remain fairly
steady through the period with highs generally in the mid 70s to low
80s and lows in the 60s.
&&
.AVIATION...(For the 18Z TAFs through 18Z Friday Afternoon)
Issued at 1231 PM CDT THU MAY 22 2014
Thunderstorms are developing just south and east of the MHK
terminal, some of these storms may affect MHK in the next couple
hours. Some of these storms may reach TOP and FOE by 19Z. After
00Z there will be a break from thunderstorms but late tonight and
early Friday, thunderstorm chances may increase. Expect mainly VFR
conditions with some MVFR ceilings in vicinity of thunderstorms,
along with reduced visibilities and gusty winds.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Hennecke
AVIATION...Gargan
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
346 PM CDT Thu May 22 2014
...Update to short term...
.SHORT TERM...(This evening through Friday)
ISSUED AT 346 PM CDT THU MAY 22 2014
Tonight:
Main concern is dealing with orographic convection to the west. Afternoon
radar mosaic shows considerable thunderstorm activity across Colorado
and New Mexico. MCS propagation vectors support the eastward translation
of this activity and will eventually reach far SW Kansas by evening.
The HRRR is insistent in generating an MCS with a cold pool. This model
does seem to be - at times- too aggressive with cold pool generation.
Still, enough isentropic lift and moisture advection supports ramping
up the pops this evening. Think the main concern is heavy rainfall as
the 12Z KDDC raob PWAT is between the 75th percentile and the +2SD mark.
This is statistically significant. Bulk shear is far from reaching supercell
archetype. Secondary threat to heavy rainfall is outflow winds, which
could impact far western Kansas along and west of Highway 83. The boundary
layer will become more stable this evening, so that could mitigate any
momentum transfer issues. In addition to convection, have increased
QPF more in line with WPC guidance. Most of the mesoscale models (HRRR/WRF/4
km NAM) all suggest that a good chunk of the region might see 0.50-1.00"
from tonights and tomorrow thunderstorm activity.
Tomorrow:
Have ramped up pops again by afternoon and evening as PWAT remains near
an 1.00" and isentropic lift/warm air advection continues through the
day. Moist adiabatic thermodynamic skew-t/log-p`s and also slow MCS
propagation vectors suggest that heavy rainfall is still a threat for
tomorrow. Highest pops will be during the afternoon to 00Z as diurnally
induced instability increases. Again, would not be surprised to see
decent rainfall amounts through 7 pm tomorrow night, as alluded to
above.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 235 PM CDT THU MAY 22 2014
Medium range models indicate a southwest flow aloft prevailing
across the Western High Plains Saturday as a closed off upper level
low shifts slowly eastward across the Four Corners Region. As the
system approaches, increased divergence aloft downstream of the
trough axis will intensify across the high plains of eastern
Colorado, western Kansas, and the panhandle of Oklahoma, especially
into Saturday evening. Meanwhile, a prevailing low level
south-southeasterly flow will continue to draw additional moisture
into the state with H85 dewpoints nearing 15C. Although the flow
aloft is expected to remain generally weak, GFS/ECMWF model
soundings do show some marginal directional shear along with SBCAPE
values in excess of 1500 J/KG. As H5 vort maxima cycle northeast out
of the trough axis into the high plains, shower and thunderstorm
development is likely with some chance for marginally severe
weather possible. However, a bigger concern may be the potential
for brief periods of heavy rainfall with model soundings also
showing PW values well over one inch.
Similar conditions will exist Sunday as the closed off upper level
low moves across the Rockies into the Western High Plains. However,
a few more thunderstorms may be possible as an upper level jet noses
northward into southwest Kansas Sunday afternoon while a developing
dryline sharpens near the Colorado border. In addition, GFS/ECMWF
model soundings indicate an inverted V profile by Sunday afternoon
with SBCAPE values pushing above 2000 J/KG. Although speed shear
looks a little more favorable than Saturday, directional shear
does not which may limit the strength of any developing storms.
However, the potential for significant rainfall lingers with PW
values remaining fairly high with values near to a little above
one inch. Shower and thunderstorm potential shifts eastward more
into central Kansas Monday as the closed off low pushes further
east into western Kansas. Drier conditions are likely by Wednesday
as weak upper level ridging fills in across the Western High
Plains in wake of the departing upper level low.
Fairly mild temperatures are likely Saturday as a cooler air mass
remains locked in across the Western High Plains The GFS/ECMWF show
H85 temperatures changing little from Friday with the mid teens(C)
across central Kansas to the upper teens(C) out near the Colorado
border. Due to expected increased cloud cover and areas of precip,
look for highs up into the upper 70s(F) to near 80F. Similar
temperatures are likely into Monday before a gradual warming
trend begins by mid week as weak upper level ridging develops
across the Intermountain West.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1200 PM CDT THU MAY 22 2014
Somewhat of an uncertain forecast in regards to convective placement/timing.
Followed HRRR guidance for this evening, which shows storms moving out
of SE Colorado and impacting KDDC/KGCK around 00Z. Other models show
less storms, but given the moist atmosphere, it will not take much to
spark a storm. A greater chance of higher coverage is expected through
the overnight as another cluster moves across. Would not rule out MVFR
in the heavier thunderstorm activity, but cigs should mainly be VFR
averaged out over time and space.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 63 79 61 80 / 70 60 60 60
GCK 61 78 60 81 / 70 60 60 60
EHA 59 76 59 80 / 70 40 50 60
LBL 61 76 61 81 / 70 60 60 60
HYS 62 78 62 80 / 40 60 60 50
P28 66 80 64 82 / 40 60 60 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sugden
LONG TERM...JJohnson
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS GOODLAND KS
148 PM MDT THU MAY 22 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 148 PM MDT THU MAY 22 2014
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS LARGE CLOSED UPPER OVER
SOUTHERN CALIFORNIA WITH RIDGE ACROSS PLAINS AND SOUTHEASTERN US.
SOUTHERLY/DIFLUENT FLOW IS IN PLACE ACROSS THE SOUTHERN PLAINS AND
ROCKIES WITH MOIST PLUME EXTENDING FROM PACIFIC NORTH WITHIN THIS
FLOW. AT THE SURFACE A STALLED FRONT IS ANALYZED ACROSS SOUTHERN KS
AND ACROSS OK/TX PANHANDLES. UPSTREAM RADARS SHOW THUNDERSTORM
ACTIVITY ALREADY DEVELOPING ACROSS NORTHEAST NEW MEXICO AND ALONG
THE FRONT RANG WITH A NORTHERLY PROGRESSION.
UPPER LEVEL ENERGY ROTATING THROUGH THE UPPER FLOW ON THE EASTERN
EDGE OF THE UPPER TROUGH WE WILL CONTINUE TO SUPPORT
SHOWER/THUNDERSTORM DEVELOPMENT. ANOMALOUSLY MOIST AIR MASS (PWATS
STANDARD DEVIATIONS ABOVE NORMAL) WILL LINGER TONIGHT THROUGH
TOMORROW.
FOR TONIGHT...THUNDERSTORMS ARE DEVELOPING IN PROXIMITY TO LARGE
SCALE DIFFLUENT FLOW OVER NEW MEXICO AND CENTRAL COLORADO. TD VALUES
AROUND 60F HAS LEAD TO SB CAPE 1500-2000 J/KG. AIR MASS BUILDING
OVER OUR CWA. GUIDANCE SHOWS MU CAPE THROUGH FRIDAY AROUND 2000 J/KG
OVER OUR CWA. GUIDANCE SUPPORTS THUNDERSTORM ACTIVITY UPSTREAM FROM
OUR CWA MERGING INTO CLUSTER/THUNDERSTORM COMPLEX AND SPREADING
NORTH INTO OUR CWA. WITH ELEVATED FRONTAL ZONE GENERALLY LINGERING
NEAR THE I-70 CORRIDOR AND MOISTURE POOLING/INSTABILITY LINGERING WE
SHOULD SEE A GOOD PATTERN FOR THIS ACTIVITY INCREASING IN COVERAGE.
0-6KM WIND IS 15KT OR LESS...HOWEVER WIND PROFILES BELOW 800MB ARE
VERY WEAK ALONG FRONTAL ZONE OUT OF THE EAST...WHILE 400-250MB WINDS
ARE STRAIGHT OUT OF THE WEST. IN ADDITION TO THE ALREADY WET SIGNAL
THIS PATTERN SUPPORT BACK BUILDING OF THUNDERSTORMS ALONG FRONTAL
ZONE AND VERY SLOW PROPAGATION OF THUNDERSTORMS. CONFIDENCE IS
INCREASING IN AT LEAST A LOCALIZED FLOODING THREAT TONIGHT...BUT IM
NOT SURE HOW WIDESPREAD THIS WILL BE SO IM HOLDING OFF ON ISSUANCE
OF FLASH FLOOD WATCH. SHEER PROFILES ARE NOT THAT
IMPRESSIVE...HOWEVER WITH MODERATE INSTABILITY/GOOD MID LEVEL LAPSE
RATES...DAMAGING WINDS ASSOCIATED WITH COLD POOL DRIVEN
THUNDERSTORM COMPLEXES OR STRONG WIND/LARGE HAIL WITH PULSE TYPE
CONVECTION CANT BE RULED OUT.
GUIDANCE SHOW GOOD 850MB SUPPORT LINGERING OVERNIGHT AND MODELS
CONTINUE TO LINGER SHOWERS/THUNDERSTORMS THROUGH TOMORROW
AFTERNOON...WITH AN ENHANCEMENT IN ACTIVITY AS SURFACE FRONT STALLS
ALONG KS/NE STATE LINE. I WAS COMFORTABLE LINGERING POPS ACROSS THE
CWA THROUGH THE SHORT TERM PERIOD...THOUGH I DID TRY TO TIME OUT THE
PERIODS BETWEEN WEAK SHORTWAVES FOR POSSIBLE LULLS IN COVERAGE. I
ALSO BUMPED UP QPF TO REFLECT PERIODS OF MODERATE-HEAVY PRECIP
POTENTIAL. THERE IS ALSO SOME POTENTIAL FOR FOG DEVELOPMENT LATE
TONIGHT/EARLY FRIDAY...HOWEVER SURFACE PATTERN COULD BE CHAOTIC IF
THUNDERSTORM ACTIVITY IS ONGOING...AND DECIDED NOT TO INCLUDE
MENTION WITH THIS UPDATE. TEMPS TONIGHT AND FRIDAY ARE TRICKY AS
MODELS WOULD SUPPORT SHOWERS/THUNDERSTORMS ACROSS THE REGION THROUGH
THESE PERIODS...AND FRONTAL POSITION IS STILL UNCERTAIN.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 324 AM MDT THU MAY 22 2014
SUNDAY THROUGH WEDNESDAY...THE UPPER LEVEL CLOSED LOW OVER THE
SOUTHWESTERN UNITED STATES WILL OPEN UP INTO A TROUGH AS IT MOVES
EAST INTO THE CENTRAL PLAINS. THIS TROUGH WILL BRING THE CHANCE FOR
SHOWERS AND THUNDERSTORMS THROUGH THE BEGINNING OF THE EXTENDED AS
VORTICITY CIRCULATES AROUND IT. TEMPERATURES THROUGH THE BEGINNING
OF THE EXTENDED WILL REMAIN NEAR NORMAL...WITH HIGHS IN THE MID 70S
TO LOW 80S ON SUNDAY AND MONDAY. AS THE UPPER TROUGH MOVES
EAST...RIDGING WILL MOVE INTO THE PLAINS BY MIDWEEK. THIS RIDGING
WILL BRING A BRIEF PERIOD OF DRY WEATHER TO THE CWA ON TUESDAY
BEFORE THE NEXT SHORTWAVE TROUGH BRINGS THE CHANCE FOR SHOWERS AND
THUNDERSTORMS BACK TO THE CWA BY WEDNESDAY. A SERIES OF SURFACE
TROUGHS WILL ALSO SET UP IN EASTERN COLORADO THROUGHOUT THE
EXTENDED...WHICH WILL BRING A FEW WIND SHIFTS AND COULD BRING
SURFACE BOUNDARIES THAT AID IN SHOWER AND THUNDERSTORM DEVELOPMENT
THROUGHOUT MOST OF THE EXTENDED. TEMPERATURES BEGIN TO WARM UP ON
TUESDAY AS THE RIDGE MOVES OVER THE PLAINS...WITH HIGHS IN THE LOW
TO MID 80S WHICH WILL CONTINUE INTO WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1122 AM MDT THU MAY 22 2014
THROUGH THE FIRST 12HR OF THE TAF PERIOD THE PRIMARY AVIATION
CONCERN WILL THE THUNDERSTORM ACTIVITY EXPECTED TO DEVELOP THIS
AFTERNOON AND SPREAD NORTHEAST OVER BOTH TERMINALS. BEST COVERAGE
WILL BE LATE AFTERNOON THROUGH THE LATE NIGHT TONIGHT
PERIOD...WITH SCATTERED SHOWERS/ISO THUNDER THEN LINGERING THROUGH
THE REST OF THE TAF PERIOD. WILL NEED TO MONITOR RADAR TRENDS AND
INTENSITY IN THE EVENT TEMPORARY IFR/MVFR CONDITIONS DEVELOP WITH
THUNDERSTORM ACTIVITY. AS THIS ACTIVITY IS WINDING DOWN MOISTURE
POOLING ALONG FRONTAL ZONE MAY LEAD TO FOG AND LOW STRATUS
DEVELOPMENT ALONG THE INTERSTATE 70 CORRIDOR...WITH LIFR CONDITIONS
POSSIBLE BY 12Z AT KGLD (AS INDICATED BY SOME GUIDANCE). IT IS WAY
TOO UNCERTAIN AT THIS POINT CONSIDERING THUNDERSTORM ACTIVITY
COULD COMPLICATE SURFACE PATTERN...AND THUS THE POTENTIAL FOR FOG.
FOR NOW I HAVE ONLY MENTIONED 3SM BR AROUND 12Z AT KGLD TO ACCOUNT
FOR THIS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...ALW
AVIATION...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
238 PM CDT Thu May 22 2014
...UPDATE TO LONG TERM...
.SHORT TERM...(Today and tonight)
ISSUED AT 350 AM CDT THU MAY 22 2014
Convection chances will be the main theme for the next 24 to 36
hours of forecast timeframe. Determining where those will be likely
to redevelop will be better suited for later in the day as the
atmosphere destabilizes again in collocation with the best low level
convergence of the stationary front or old outflow boundaries. Models
indicate precipitation already early in the day, possibly overdone
owing to the mean layer CAPE but not out the plausibility. If
easterly to southeasterly flow redevelops which appears likely,
another round of late afternoon or mainly late evening thunderstorms
is likely for any part of the area as is being shown in recent NMM/ARW
WRF model runs both (00 and 06 UTC runs). These evening MCS trends
were followed for the overall precipitation chance trends late today
and tonight. Model soundings this evening show generally
unidirectional flow rather than very strong low level veering which
would tend to support clusters or weak qlcs type storm structures.
In the meantime, the afternoon should be warm and humid. Most of the
model guidance indicates 80-s to around 90 across the southern
counties. Old convective outflow may moderate the temperature
heating curve from what the models produce.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 235 PM CDT THU MAY 22 2014
Medium range models indicate a southwest flow aloft prevailing
across the Western High Plains Saturday as a closed off upper level
low shifts slowly eastward across the Four Corners Region. As the
system approaches, increased divergence aloft downstream of the
trough axis will intensify across the high plains of eastern
Colorado, western Kansas, and the panhandle of Oklahoma, especially
into Saturday evening. Meanwhile, a prevailing low level
south-southeasterly flow will continue to draw additional moisture
into the state with H85 dewpoints nearing 15C. Although the flow
aloft is expected to remain generally weak, GFS/ECMWF model
soundings do show some marginal directional shear along with SBCAPE
values in excess of 1500 J/KG. As H5 vort maxima cycle northeast out
of the trough axis into the high plains, shower and thunderstorm
development is likely with some chance for marginally severe
weather possible. However, a bigger concern may be the potential
for brief periods of heavy rainfall with model soundings also
showing PW values well over one inch.
Similar conditions will exist Sunday as the closed off upper level
low moves across the Rockies into the Western High Plains. However,
a few more thunderstorms may be possible as an upper level jet noses
northward into southwest Kansas Sunday afternoon while a developing
dryline sharpens near the Colorado border. In addition, GFS/ECMWF
model soundings indicate an inverted V profile by Sunday afternoon
with SBCAPE values pushing above 2000 J/KG. Although speed shear
looks a little more favorable than Saturday, directional shear
does not which may limit the strength of any developing storms.
However, the potential for significant rainfall lingers with PW
values remaining fairly high with values near to a little above
one inch. Shower and thunderstorm potential shifts eastward more
into central Kansas Monday as the closed off low pushes further
east into western Kansas. Drier conditions are likely by Wednesday
as weak upper level ridging fills in across the Western High
Plains in wake of the departing upper level low.
Fairly mild temperatures are likely Saturday as a cooler air mass
remains locked in across the Western High Plains The GFS/ECMWF show
H85 temperatures changing little from Friday with the mid teens(C)
across central Kansas to the upper teens(C) out near the Colorado
border. Due to expected increased cloud cover and areas of precip,
look for highs up into the upper 70s(F) to near 80F. Similar
temperatures are likely into Monday before a gradual warming
trend begins by mid week as weak upper level ridging develops
across the Intermountain West.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1200 PM CDT THU MAY 22 2014
Somewhat of an uncertain forecast in regards to convective placement/timing.
Followed HRRR guidance for this evening, which shows storms moving out
of SE Colorado and impacting KDDC/KGCK around 00Z. Other models show
less storms, but given the moist atmosphere, it will not take much to
spark a storm. A greater chance of higher coverage is expected through
the overnight as another cluster moves across. Would not rule out MVFR
in the heavier thunderstorm activity, but cigs should mainly be VFR
averaged out over time and space.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 63 79 61 80 / 70 60 60 60
GCK 61 78 60 81 / 70 60 60 60
EHA 59 76 59 80 / 70 40 50 60
LBL 61 76 61 81 / 70 60 60 60
HYS 62 78 62 80 / 40 60 60 50
P28 66 80 64 82 / 40 60 60 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...JJohnson
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1200 PM CDT Thu May 22 2014
...Update to aviation...
.SYNOPSIS...
ISSUED AT 940 AM CDT THU MAY 22 2014
The 22.12Z 250-hPa map showed broad southwesterly flow aloft ahead of
a longwave trough across the Desert SW and extending into Kansas. At
500-hPa, a closed circulation was noted across California and Nevada.
Some mid-level moisture was advecting northward ahead of this pressure
perturbation. At the lower levels for KDDC, moisture advection was noted
for the RAOB with the total PWAT column at 1.08" (between the 75th percentile
and 2SD mark). The entire sounding is conducive to heavy rain. Wind
shear was pretty weak too. At the surface, a stationary boundary was
analyzed across Kansas with plenty of low level moisture across the
state (dew points in the 50s and 60s).
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 350 AM CDT THU MAY 22 2014
Convection chances will be the main theme for the next 24 to 36
hours of forecast timeframe. Determining where those will be likely
to redevelop will be better suited for later in the day as the
atmosphere destabilizes again in collocation with the best low level
convergence of the stationary front or old outflow boundaries. Models
indicate precipitation already early in the day, possibly overdone
owing to the mean layer CAPE but not out the plausibility. If
easterly to southeasterly flow redevelops which appears likely,
another round of late afternoon or mainly late evening thunderstorms
is likely for any part of the area as is being shown in recent NMM/ARW
WRF model runs both (00 and 06 UTC runs). These evening MCS trends
were followed for the overall precipitation chance trends late today
and tonight. Model soundings this evening show generally
unidirectional flow rather than very strong low level veering which
would tend to support clusters or weak qlcs type storm structures.
In the meantime, the afternoon should be warm and humid. Most of the
model guidance indicates 80-s to around 90 across the southern
counties. Old convective outflow may moderate the temperature
heating curve from what the models produce.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 411 AM CDT THU MAY 22 2014
The first several days of the long term period will see decent
chances for rain and thunderstorms across western and central
Kansas. At the beginning of the period, a closed upper low will be
situated over southwest Arizona while an upper level ridge axis will
extend from the northern High Plains into the lower Mississippi
Valley. A fairly deep layer of moist southerly flow will extend from
the western Gulf Coast into the eastern slopes of the Rockies. The
upper level low will gradually move east toward the central High
Plains through the weekend. Upper level disturbances rotating around
the upper low will periodically eject northward into the central
High Plains...bringing daily rounds of thunderstorms to the area
through Monday.
During the early to middle part of next week, another upper level
trough will move into western North America which will effectively
kick the central Plains upper low eastward out of the High Plains
toward the mid Mississippi Valley. Chances for showers and
thunderstorms will decrease significantly once the upper low moves
east of the region.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1200 PM CDT THU MAY 22 2014
Somewhat of an uncertain forecast in regards to convective placement/timing.
Followed HRRR guidance for this evening, which shows storms moving out
of SE Colorado and impacting KDDC/KGCK around 00Z. Other models show
less storms, but given the moist atmosphere, it will not take much to
spark a storm. A greater chance of higher coverage is expected through
the overnight as another cluster moves across. Would not rule out MVFR
in the heavier thunderstorm activity, but cigs should mainly be VFR
averaged out over time and space.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 87 62 81 61 / 30 60 50 60
GCK 86 60 80 60 / 30 60 50 50
EHA 86 59 80 59 / 40 70 40 40
LBL 87 61 81 61 / 40 70 50 40
HYS 84 61 81 62 / 30 60 60 60
P28 90 65 84 64 / 30 50 50 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Russell
LONG TERM...Gerard
AVIATION...Sugden
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
635 PM EDT THU MAY 22 2014
.UPDATE...
ISSUED AT 635 PM EDT THU MAY 22 2014
WITH THE WORST OF THE STORMS SINKING SOUTH OUT OF EAST KENTUCKY HAVE
GONE AHEAD AND DROPPED THE SEVERE WATCH FOR WAYNE AND MCCREARY
COUNTIES. ALSO TAPERED OFF THE THUNDERSTORM CHANCES THROUGH THE REST
OF THE EVENING AND ADDED SOME PATCHY DENSE FOG TO THE VALLEYS LATE
TONIGHT. FINALLY...TWEAKED THE NEAR TERM GRIDS PER THE LATEST OBS AND
TRENDS. THESE GRID UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS
ALONG WITH THE DISSEMINATION OF THE ZFP AND WCN. AN UPDATED HWO IS IN
THE QUEUE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 415 PM EDT THU MAY 22 2014
19Z SFC ANALYSIS SHOWS LOW PRESSURE CENTERED OVER THE POCONOS WITH A
COLD FRONT STRETCHED SOUTHWEST AND BISECTING KENTUCKY. SOUTH OF THIS
FRONT DEWPOINTS ARE IN THE MID AND UPPER 60S WITH TEMPERATURES IN THE
MID 80S. CONDITIONS ARE JUST A BIT DRIER AND COOLER TO THE NORTHWEST
OF IT. TO THE SOUTH OF THE FRONT...INSTABILITY IS QUITE HIGH WITH
LIS IN THE -8 TO -10 DEGREE RANGE WITH CAPE TO 3500 J/KG OVER THE
WESTERN PORTION OF THE STATE. ON SATELLITE...THE CU IS DOING BEST
OVER SOUTHERN KENTUCKY...WHILE ON RADAR SOME RETURNS ARE FINALLY
SHOWING UP TO THE NORTHWEST OF BOWLING GREEN. EXPECT THESE TO DEVELOP
AND STRENGTHEN RAPIDLY WITH A GENERAL MOVEMENT TO THE EAST SOUTHEAST.
SPC HAS HIGHLIGHTED THIS AREA THROUGH SOUTHERN PARTS OF EAST KENTUCKY
FOR A POTENTIAL WATCH BOX. MEANWHILE...WINDS ARE MAINLY FROM THE WEST
AT 10 TO 20 KTS ACROSS EAST KENTUCKY.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH THE FAST NORTHWEST FLOW
THROUGH NORTHEAST KENTUCKY BETWEEN A RETREATING RIDGE TO THE SOUTH
AND EXPANDING TROUGHING TO THE NORTH. A WEAK PATCH OF ENERGY WILL
PASS THROUGH THIS NORTHWEST FLOW KNOCKING DOWN HEIGHTS LOCALLY INTO
THE EVENING. THE RIDGE IS FURTHER SUPPRESSED ON FRIDAY IN RESPONSE TO
THE NORTHEAST TROUGH DIGGING THROUGH THE CENTRAL APPALACHIANS. ONCE
THIS TROUGH AND SHARP SHORTWAVE MOVES OUT OF THE AREA...HEIGHTS WILL
REBOUND OVER EAST KENTUCKY INTO SATURDAY MORNING. WITH THE GOOD MODEL
AGREEMENT WILL FOLLOW THE DETAILS FROM THE NAM12 AND THE LAST FEW
RUNS OF THE HRRR MOST PROMINENTLY.
SENSIBLE WEATHER WILL FEATURE SCATTERED STORMS OVER THE SOUTHERN
HALF OF THE CWA THIS EVENING...POTENTIALLY SEVERE ALONG THE TENNESSEE
BORDER. A WATCH BOX IS NOW OUT WITH WAYNE AND MCCREARY INCLUDED...AND
JUST IN TIME AS THE STORMS ARE QUICKLY DEVELOPING OVER OUR SOUTHERN
TIER. EXPECT THESE TO FADE OUT BY MIDNIGHT WITH SOME CLEARING HELPING
TO BUILD FOG THROUGH THE VALLEYS ACROSS EAST KENTUCKY. THE FOG COULD
BECOME LOCALLY DENSE IN THE DEEPEST VALLEYS. THE FRONT DRIFTS TO THE
SOUTH OF THE AREA ON FRIDAY TAKING THE THREAT OF SHOWERS AND
THUNDERSTORMS WITH IT. THIS SHOULD MAKE FOR A PLEASANT END TO THE
WORK WEEK WITH TEMPERATURES ABOUT 5 TO 10 DEGREES COOLER THAN TODAY.
LATER FRIDAY NIGHT...ANTICIPATE A DECENT RIDGE TO VALLEY TEMPERATURE
SPLIT GIVEN MOSTLY CLEAR SKIES AND HIGH PRESSURE MOVING BY TO THE
NORTH. SOME PATCHY VALLEY FOG CAN ALSO BE EXPECTED TO DEVELOP
TOWARDS DAWN SATURDAY.
USED THE BCCONSSHORT GRIDS AS A STARTING POINT FOR TEMPERATURES...
DEWPOINTS...AND WINDS THROUGH THE FIRST 24 HOURS WITH THE BCCONSALL
ADDED TO THE END OF THE SHORT TERM THEREAFTER. MOST ADJUSTMENTS
WHERE MADE TO ACCOUNT FOR TERRAIN DIFFERENCES TONIGHT AND FRIDAY
NIGHT IN THE LOWS. AS FOR POPS...ENDED UP ON THE HIGH SIDE OF ALL
GUIDANCE TONIGHT AND THEN SINGLE DIGITS THROUGH THE REST OF THE
PERIOD...IN LINE WITH THE MOS NUMBERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 315 PM EDT THU MAY 22 2014
CONDITIONS WILL STAY FAIRLY CONSTANT IN THE UPPER LEVELS DURING THE
EXTENDED...WITH THE MODELS IN FAIRLY GOOD AGREEMENT THROUGH DAY 7.
SATURDAY 12Z WILL START OFF THE PERIOD WITH AN UPPER LEVEL RIDGE
MOVING FROM THE CENTRAL PLAINS ACROSS EASTERN KY. THIS RIDGE WILL
REMAIN THE DRIVING FORCE THROUGH TUESDAY. FOR THE MID TERM SECTION
OF THE FORECAST PERIOD...ANY MOISTURE WILL REMAIN TO THE WEST OF THE
RIDGE...KEEPING MUCH OF KY BOTH DRY AND IN A SOUTHERLY WIND PATTERN.
THIS WILL ALLOW TEMPERATURES TO BOOST TO WELL ABOVE NORMAL THROUGH
EARLY NEXT WEEK. SATURDAY IS STILL EXPECTED TO BE THE COOLEST DAY AS
HIGH PRESSURE AND UPPER LEVEL RIDGING ARE JUST BEGINNING TO TAKE
CONTROL...WITH HIGHS NEAR CLIMATOLOGICAL NORMAL FOR THIS TIME OF
YEAR. TEMPERATURES SATURDAY NIGHT WILL SHOW A DECENT DIURNAL RANGE
WITH A THERMAL BELT SETTING UP AROUND THE RIDGES. THEN AS SOUTHERLY
FLOW TAKES CONTROL...TEMPS WILL BEGIN TO RISE INTO THE MID AND EVEN
SOME UPPER 80S BY TUESDAY OF NEXT WEEK.
MODELS ARE SHOWING SOME VARIATION IN SOME ISOLATED TO SCATTERED
AFTERNOON SHOWERS/TSTORMS FOR MONDAY AND TUESDAY
AFTERNOON...ALTHOUGH NO PARTICULAR MODEL IS GOING TO HAVE A GOOD
HANDLE WHERE THEY WILL SET UP EXACTLY. THERE IS ENOUGH EVIDENCE TO
WARRANT ISOLATED CHANCES ON MONDAY...AND SCATTERED CHANCES ACROSS
EASTERN KY FOR TUESDAY. BY TUESDAY EVENING...LOW PRESSURE OVER THE
SOUTH CENTRAL PLAINS WILL HAVE SHIFTED EASTWARD SLIGHTLY AND WILL BE
ENTERING INTO THE MISSISSIPPI RIVER VALLEY. THIS WILL CREATE MORE
LIFT AND MOISTURE INFLUX...AS WELL AS CONTINUED WARM UNSTABLE
AIR...ALLOWING THE CHANCE OF SHOWERS AND THUNDERSTORMS TO CONTINUE
TUESDAY NIGHT INTO THURSDAY TO ROUND OUT OUR FORECAST PERIOD. STUCK
PRETTY CLOSE TO THE ALLBLEND FOR THE EXTENDED POPS DUE TO THE
UNCERTAINTY IN CONVECTION THIS FAR OUT IN THE FORECAST PERIOD.
SMOOTHED OUT ANY MAJOR BULLSEYES OF POPS AND LOWERED SOME OF THE
HIGHER END CHANCES THAT ARE HARD TO WARRANT THIS FAR OUT.
OTHERWISE...WE ARE MATCHING UP QUITE WELL WITH SURROUNDING OFFICES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 215 PM EDT THU MAY 22 2014
HAVE SPLIT THE TAFS FOR A STORM THREAT THIS AFTERNOON AND INTO THE
EARLY EVENING WITH JKL AND SJS LEFT OUT. GIVEN THE UNCERTAINTY HAVE
KEPT THIS JUST AS A VCTS MENTION FOR SME AND LOZ THROUGH 23Z. THE
GROUND MOISTURE LEFT BEHIND FROM THE STORMS LAST NIGHT AND ANY THE
TAKE SHAPE LATER THIS AFTERNOON WILL LIKELY BE ENOUGH FOR AREAS OF
FOG...LOCALLY DENSE IN SOME OF THE DEEPER VALLEYS...AND LIFR AT SME
AND LOZ...AS SKIES GO AT LEAST PARTIALLY CLEAR TONIGHT. THE FOG WILL
CLEAR OUT BY MID MORNING ON FRIDAY WITH ANY CLOUDS DEVELOPING LIKELY
STAYING VFR. WINDS WILL BE BREEZY FROM THE WEST SOUTHWEST THIS
AFTERNOON WITH SPEEDS OF 10 TO 20 KTS BEFORE SETTLING DOWN INTO
SINGLE DIGITS FROM THE NORTHWEST LATER TONIGHT...CONTINUING INTO THE
DAY FRIDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
415 PM EDT THU MAY 22 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 415 PM EDT THU MAY 22 2014
19Z SFC ANALYSIS SHOWS LOW PRESSURE CENTERED OVER THE POCONOS WITH A
COLD FRONT STRETCHED SOUTHWEST AND BISECTING KENTUCKY. SOUTH OF THIS
FRONT DEWPOINTS ARE IN THE MID AND UPPER 60S WITH TEMPERATURES IN THE
MID 80S. CONDITIONS ARE JUST A BIT DRIER AND COOLER TO THE NORTHWEST
OF IT. TO THE SOUTH OF THE FRONT...INSTABILITY IS QUITE HIGH WITH
LIS IN THE -8 TO -10 DEGREE RANGE WITH CAPE TO 3500 J/KG OVER THE
WESTERN PORTION OF THE STATE. ON SATELLITE...THE CU IS DOING BEST
OVER SOUTHERN KENTUCKY...WHILE ON RADAR SOME RETURNS ARE FINALLY
SHOWING UP TO THE NORTHWEST OF BOWLING GREEN. EXPECT THESE TO DEVELOP
AND STRENGTHEN RAPIDLY WITH A GENERAL MOVEMENT TO THE EAST SOUTHEAST.
SPC HAS HIGHLIGHTED THIS AREA THROUGH SOUTHERN PARTS OF EAST KENTUCKY
FOR A POTENTIAL WATCH BOX. MEANWHILE...WINDS ARE MAINLY FROM THE WEST
AT 10 TO 20 KTS ACROSS EAST KENTUCKY.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH THE FAST NORTHWEST FLOW
THROUGH NORTHEAST KENTUCKY BETWEEN A RETREATING RIDGE TO THE SOUTH
AND EXPANDING TROUGHING TO THE NORTH. A WEAK PATCH OF ENERGY WILL
PASS THROUGH THIS NORTHWEST FLOW KNOCKING DOWN HEIGHTS LOCALLY INTO
THE EVENING. THE RIDGE IS FURTHER SUPPRESSED ON FRIDAY IN RESPONSE TO
THE NORTHEAST TROUGH DIGGING THROUGH THE CENTRAL APPALACHIANS. ONCE
THIS TROUGH AND SHARP SHORTWAVE MOVES OUT OF THE AREA...HEIGHTS WILL
REBOUND OVER EAST KENTUCKY INTO SATURDAY MORNING. WITH THE GOOD MODEL
AGREEMENT WILL FOLLOW THE DETAILS FROM THE NAM12 AND THE LAST FEW
RUNS OF THE HRRR MOST PROMINENTLY.
SENSIBLE WEATHER WILL FEATURE SCATTERED STORMS OVER THE SOUTHERN
HALF OF THE CWA THIS EVENING...POTENTIALLY SEVERE ALONG THE TENNESSEE
BORDER. A WATCH BOX IS NOW OUT WITH WAYNE AND MCCREARY INCLUDED...AND
JUST IN TIME AS THE STORMS ARE QUICKLY DEVELOPING OVER OUR SOUTHERN
TIER. EXPECT THESE TO FADE OUT BY MIDNIGHT WITH SOME CLEARING HELPING
TO BUILD FOG THROUGH THE VALLEYS ACROSS EAST KENTUCKY. THE FOG COULD
BECOME LOCALLY DENSE IN THE DEEPEST VALLEYS. THE FRONT DRIFTS TO THE
SOUTH OF THE AREA ON FRIDAY TAKING THE THREAT OF SHOWERS AND
THUNDERSTORMS WITH IT. THIS SHOULD MAKE FOR A PLEASANT END TO THE
WORK WEEK WITH TEMPERATURES ABOUT 5 TO 10 DEGREES COOLER THAN TODAY.
LATER FRIDAY NIGHT...ANTICIPATE A DECENT RIDGE TO VALLEY TEMPERATURE
SPLIT GIVEN MOSTLY CLEAR SKIES AND HIGH PRESSURE MOVING BY TO THE
NORTH. SOME PATCHY VALLEY FOG CAN ALSO BE EXPECTED TO DEVELOP
TOWARDS DAWN SATURDAY.
USED THE BCCONSSHORT GRIDS AS A STARTING POINT FOR TEMPERATURES...
DEWPOINTS...AND WINDS THROUGH THE FIRST 24 HOURS WITH THE BCCONSALL
ADDED TO THE END OF THE SHORT TERM THEREAFTER. MOST ADJUSTMENTS
WHERE MADE TO ACCOUNT FOR TERRAIN DIFFERENCES TONIGHT AND FRIDAY
NIGHT IN THE LOWS. AS FOR POPS...ENDED UP ON THE HIGH SIDE OF ALL
GUIDANCE TONIGHT AND THEN SINGLE DIGITS THROUGH THE REST OF THE
PERIOD...IN LINE WITH THE MOS NUMBERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 315 PM EDT THU MAY 22 2014
CONDITIONS WILL STAY FAIRLY CONSTANT IN THE UPPER LEVELS DURING THE
EXTENDED...WITH THE MODELS IN FAIRLY GOOD AGREEMENT THROUGH DAY 7.
SATURDAY 12Z WILL START OFF THE PERIOD WITH AN UPPER LEVEL RIDGE
MOVING FROM THE CENTRAL PLAINS ACROSS EASTERN KY. THIS RIDGE WILL
REMAIN THE DRIVING FORCE THROUGH TUESDAY. FOR THE MID TERM SECTION
OF THE FORECAST PERIOD...ANY MOISTURE WILL REMAIN TO THE WEST OF THE
RIDGE...KEEPING MUCH OF KY BOTH DRY AND IN A SOUTHERLY WIND PATTERN.
THIS WILL ALLOW TEMPERATURES TO BOOST TO WELL ABOVE NORMAL THROUGH
EARLY NEXT WEEK. SATURDAY IS STILL EXPECTED TO BE THE COOLEST DAY AS
HIGH PRESSURE AND UPPER LEVEL RIDGING ARE JUST BEGINNING TO TAKE
CONTROL...WITH HIGHS NEAR CLIMATOLOGICAL NORMAL FOR THIS TIME OF
YEAR. TEMPERATURES SATURDAY NIGHT WILL SHOW A DECENT DIURNAL RANGE
WITH A THERMAL BELT SETTING UP AROUND THE RIDGES. THEN AS SOUTHERLY
FLOW TAKES CONTROL...TEMPS WILL BEGIN TO RISE INTO THE MID AND EVEN
SOME UPPER 80S BY TUESDAY OF NEXT WEEK.
MODELS ARE SHOWING SOME VARIATION IN SOME ISOLATED TO SCATTERED
AFTERNOON SHOWERS/TSTORMS FOR MONDAY AND TUESDAY
AFTERNOON...ALTHOUGH NO PARTICULAR MODEL IS GOING TO HAVE A GOOD
HANDLE WHERE THEY WILL SET UP EXACTLY. THERE IS ENOUGH EVIDENCE TO
WARRANT ISOLATED CHANCES ON MONDAY...AND SCATTERED CHANCES ACROSS
EASTERN KY FOR TUESDAY. BY TUESDAY EVENING...LOW PRESSURE OVER THE
SOUTH CENTRAL PLAINS WILL HAVE SHIFTED EASTWARD SLIGHTLY AND WILL BE
ENTERING INTO THE MISSISSIPPI RIVER VALLEY. THIS WILL CREATE MORE
LIFT AND MOISTURE INFLUX...AS WELL AS CONTINUED WARM UNSTABLE
AIR...ALLOWING THE CHANCE OF SHOWERS AND THUNDERSTORMS TO CONTINUE
TUESDAY NIGHT INTO THURSDAY TO ROUND OUT OUR FORECAST PERIOD. STUCK
PRETTY CLOSE TO THE ALLBLEND FOR THE EXTENDED POPS DUE TO THE
UNCERTAINTY IN CONVECTION THIS FAR OUT IN THE FORECAST PERIOD.
SMOOTHED OUT ANY MAJOR BULLSEYES OF POPS AND LOWERED SOME OF THE
HIGHER END CHANCES THAT ARE HARD TO WARRANT THIS FAR OUT.
OTHERWISE...WE ARE MATCHING UP QUITE WELL WITH SURROUNDING OFFICES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 215 PM EDT THU MAY 22 2014
HAVE SPLIT THE TAFS FOR A STORM THREAT THIS AFTERNOON AND INTO THE
EARLY EVENING WITH JKL AND SJS LEFT OUT. GIVEN THE UNCERTAINTY HAVE
KEPT THIS JUST AS A VCTS MENTION FOR SME AND LOZ THROUGH 23Z. THE
GROUND MOISTURE LEFT BEHIND FROM THE STORMS LAST NIGHT AND ANY THE
TAKE SHAPE LATER THIS AFTERNOON WILL LIKELY BE ENOUGH FOR AREAS OF
FOG...LOCALLY DENSE IN SOME OF THE DEEPER VALLEYS...AND LIFR AT SME
AND LOZ...AS SKIES GO AT LEAST PARTIALLY CLEAR TONIGHT. THE FOG WILL
CLEAR OUT BY MID MORNING ON FRIDAY WITH ANY CLOUDS DEVELOPING LIKELY
STAYING VFR. WINDS WILL BE BREEZY FROM THE WEST SOUTHWEST THIS
AFTERNOON WITH SPEEDS OF 10 TO 20 KTS BEFORE SETTLING DOWN INTO
SINGLE DIGITS FROM THE NORTHWEST LATER TONIGHT...CONTINUING INTO THE
DAY FRIDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
215 PM EDT THU MAY 22 2014
.UPDATE...
ISSUED AT 200 PM EDT THU MAY 22 2014
WATCHING FOR CONVECTIVE DEVELOPMENT OVER WESTERN KENTUCKY WHERE THE
NAM12 AND HRRR SUGGEST THAT AN MCS MAY BE SPAWNED THIS AFTERNOON. IN
THIS LOCATION...DEWPOINTS ARE IN THE LOWER 70S WITH TEMPS
APPROACHING THE MID 80S. THIS RESULTS IN CAPE AND LIS THAT ARE QUITE
SUPPORTIVE OF STRONG TO SEVERE STORMS. HOWEVER...DESPITE THE
BOUNDARY FROM THE EARLIER STORMS CUTTING THROUGH THE UNSTABLE AIR...
THE RADARS HAVE REMAINED CLEAN. THERE IS SOME CU FORMING ACROSS THE
SOUTHERN PORTION OF THE STATE BUT THE DEPTH OF THESE IS NOT TOO
IMPRESSIVE...AS OF YET. HAVE UPDATED THE FORECAST THROUGH 00Z TO
HONE IN ON THE THREAT OF STORMS ACROSS OUR SOUTH. ALSO FINE TUNED THE
SKY/T/TD GRIDS TO REFLECT THE LATEST OBS AND TRENDS. THESE HAVE BEEN
SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 1040 AM EDT THU MAY 22 2014
14Z SFC ANALYSIS SHOWS LOW PRESSURE HAS NOW MOVED TO OVER UPSTATE NEW
YORK WHILE ITS COLD FRONT STRETCHES SOUTHWEST THROUGH KENTUCKY.
EARLIER CONVECTION HAS PUSHED SOUTH OF EAST KENTUCKY...BUT ALSO LEFT
BEHIND AN OUTFLOW BOUNDARY THAT COULD BECOME SIGNIFICANT WITH DAYTIME
HEATING AND INSTABILITY. THE HRRR AND NAM12 KEEP MOST OF THE
REDEVELOPMENT SOUTH AND EAST OF OUR AREA LATER TODAY...BUT WITH THAT
BOUNDARY IN PLACE AND THE HISTORY OF THIS SYSTEM SEVERE WEATHER WILL
REMAIN A POSSIBILITY OVER FAR SOUTHERN PARTS OF THE CWA. FOR NOW...
THOUGH...IN THE WAKE OF THE EARLY MORNING STORMS A LULL WILL SET IN
FOR THE BULK OF EAST KENTUCKY. IN FACT...A PLEASANT DAY WILL BE HAD
FOR MOST WITH PARTLY SUNNY SKIES AND ANY STORMS STAYING TO THE SOUTH.
HOWEVER...THOSE SOUTHERN LOCALES...GENERALLY FROM THE HAL ROGERS
PARKWAY TO THE TENNESSEE BORDER...WILL HAVE TO BE ON THE LOOK OUT FOR
STORMS LATER THIS AFTERNOON AND SOME OF THESE COULD BE QUITE STRONG
WITH LARGE HAIL AND DAMAGING WIND GUSTS THE MAIN THREATS. HAVE
UPDATED THE GRIDS...ZONES...AND HWO TO REFLECT THESE EXPECTATIONS AND
ALSO INCORPORATED THE LATEST GUIDANCE...OBS...AND TRENDS INTO THE T
AND TD GRIDS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 345 AM EDT THU MAY 22 2014
MODELS HAVE BEEN HAVING A DIFFICULT TIME RESOLVING THE CLUSTERS OF
THUNDERSTORMS THAT HAVE BEEN PLAGUING THE AREA SINCE LATE WEDNESDAY
EVENING. THE FORECAST FROM 6Z THROUGH NOW WERE UPDATED MOSTLY USING
THE LATEST TRENDS OBSERVED IN RADAR AND SATELLITE IMAGERY. CURRENT
ACTIVITY HAS BEEN SHOWING A STEADY WEAKENING TREND OVER THE PAST HOUR
OR SO. ALL INDICATIONS ARE THAT ANY REMAINING THUNDERSTORMS WILL
PRODUCE MINIMAL WIND GUSTS AND ISOLATED INSTANCES OF LOCALLY HEAVY
RAINFALL THROUGH THE REMAINDER OF THE OVERNIGHT. MORE STORMS CONTINUE
TO FORM IN A PREFERRED AREA OF LIFT AND MOISTURE CONVERGENCE ACROSS
SOUTHERN INDIANA AND WILL LIKELY CONTINUE TO MOVE ACROSS CENTRAL AND
EASTERN KENTUCKY THROUGH EARLY THIS MORNING. THE MODELS ARE
INDICATING THAT THERE WILL BE BRIEF LULL IN ACTIVITY IN THE
MORNING...BEFORE THINGS RAMP BACK UP A BIT DURING THE AFTERNOON HOURS
AS A COLD FRONT SAGS SLOWLY SOUTHWARD ACROSS THE REGION OUT OF THE
OHIO VALLEY. THE MODEL CONSENSUS SAYS THAT THE LAST SHOWERS AND
STORMS WILL BE OUT OF THE AREA AROUND 5Z FRIDAY. THERE IS A SLIGHT
RISK THAT A FEW STORMS COULD APPROACH SEVERE LIMITS ALONG AND JUST
NORTH OF THE TENNESSEE BORDER TODAY...AS THIS WAS MENTIONED IN THE
HAZARDOUS WEATHER OUTLOOK EVEN THOUGH CONFIDENCE IS NOT HIGH THAT
THIS WILL OCCUR. STRONG WINDS AND LARGE HAIL WOULD BE THE PRIMARY
THREATS WITH ANY STORMS THAT REACH SEVERE STATUS. THE WEATHER FOR
THURSDAY NIGHT AND FRIDAY WILL DRY AND SLIGHTLY COOLER AS ANOTHER
RIDGE OF HIGH PRESSURE SETTLES OVER THE AREA.
TEMPERATURES TODAY WILL BE RUNNING ABOVE NORMAL ONCE AGAIN WITH
READINGS EXPECTED TO TOP OUT AROUND 80 DEGREES ACROSS THE AREA AS THE
AIR MASS BEHIND THE COLD FRONT QUICKLY MODIFIES. THE FRONT ITSELF IS
NOT ALL THAT WELL DEFINED SO THE AIR BEHIND IT WILL PROBABLY NOT COOL
THINGS OFF VERY MUCH ONCE THE FRONT HAS PASSED. IN SPITE OF THE
SLIGHTLY COOLER AIR MASS...TEMPERATURES ON FRIDAY SHOULD STILL BE
ABLE TO TOP OUT IN THE UPPER 70S ACROSS THE BOARD.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT THU MAY 22 2014
THE MODELS IN THE LONG TERM START OUT IN VERY GOOD AGREEMENT WITH A
CUT OFF UPPER LOW OVER ARIZONA...UPPER RIDGING OVER THE PLAINS AND
AN UPPER TROUGH OVER THE EAST COAST. AT THE SURFACE HIGH PRESSURE IS
DOMINATING THE AREA. THE UPPER LOW OVER ARIZONA TRACKS SLOWLY TO THE
NORTHEAST OVER TIME AS THE RIDGE AXIS MOVE SLOWLY TO THE EAST AND
WILL BE LOCATED OVER THE MISSISSIPPI VALLEY BY SATURDAY EVENING. BY
TUESDAY AFTERNOON...SOME AFTERNOON AIR MASS THUNDERSTORMS MAY BE
POSSIBLE AS THE UPPER LOW APPROACHES THE AREA. BY THIS TIME THE
MODELS ARE STARTING TO DIVERGE AND CONFIDENCE PLUMMETS. ISOLATED TO
SCATTERED THUNDERSTORMS WILL BE POSSIBLE THROUGH THE END OF THE
PERIOD. FOR TEMPERATURES...STAYED CLOSE TO THE MODEL BLEND...HOWEVER
NUDGED THEM TOWARD THE RAW ECMWF AND MADE CORRECTIONS DUE TO
TERRAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 215 PM EDT THU MAY 22 2014
HAVE SPLIT THE TAFS FOR A STORM THREAT THIS AFTERNOON AND INTO THE
EARLY EVENING WITH JKL AND SJS LEFT OUT. GIVEN THE UNCERTAINTY HAVE
KEPT THIS JUST AS A VCTS MENTION FOR SME AND LOZ THROUGH 23Z. THE
GROUND MOISTURE LEFT BEHIND FROM THE STORMS LAST NIGHT AND ANY THE
TAKE SHAPE LATER THIS AFTERNOON WILL LIKELY BE ENOUGH FOR AREAS OF
FOG...LOCALLY DENSE IN SOME OF THE DEEPER VALLEYS...AND LIFR AT SME
AND LOZ...AS SKIES GO AT LEAST PARTIALLY CLEAR TONIGHT. THE FOG WILL
CLEAR OUT BY MID MORNING ON FRIDAY WITH ANY CLOUDS DEVELOPING LIKELY
STAYING VFR. WINDS WILL BE BREEZY FROM THE WEST SOUTHWEST THIS
AFTERNOON WITH SPEEDS OF 10 TO 20 KTS BEFORE SETTLING DOWN INTO
SINGLE DIGITS FROM THE NORTHWEST LATER TONIGHT...CONTINUING INTO THE
DAY FRIDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...JJ
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS CARIBOU ME
640 PM EDT THU MAY 22 2014
.SYNOPSIS...
WE WILL REMAIN IN A REGION OF LIGHT FLOW BETWEEN LOW PRESSURE
SYSTEMS TO OUR EAST AND WEST THROUGH FRIDAY. WEAK HIGH PRESSURE
WILL PRESS INTO THE AREA ON SATURDAY. A SMALL LOW WILL APPROACH
FROM THE NORTH LATE SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
0630 PM UPDATE: SCATTERED SHOWERS CONTINUE TO AFFECT MUCH OF THE
REGION AT THIS HOUR. BASED ON LATEST RADAR AND HRRR MODEL RUN,
INCREASED POPS THIS EVENING. ALSO MADE SOME MINOR ADJUSTMENTS TO
CLOUD COVER, TEMPERATURE, WIND GRIDS FOR THIS EVENING.
PREVIOUS DISCUSSION: A LARGE AND WEAK UPPER LEVEL LOW WILL REMAIN
ACROSS THE AREA TONIGHT AND FRIDAY AS WEAK SURFACE LOWS REMAIN TO
OUR WEST AND EAST. TONIGHT WILL BE PARTLY TO MOSTLY CLOUDY WITH
SOME SCATTERED SHOWERS THIS EVENING AND PATCHY FOG LATE TONIGHT.
FRIDAY WILL BE SIMILAR TO TODAY WITH A MOSTLY CLOUDY SKY, SOME
BRIEF BREAKS OF SUNSHINE, AND SOME SMALL SCALE CONVECTION
PRODUCING SCATTERED SHOWERS MAINLY DURING THE MIDDAY AND
AFTERNOON. TEMPS WILL BE SIMILAR TO TODAY`S ALTHOUGH HIGH PRESSURE
WELL TO THE NORTH WILL PUSH SOME SLIGHTLY COOLER MARITIME AIR
ACROSS THE REGION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A WEAK UPPER SFC TROF IS FCST TO XTND NE-SW DOWN ACROSS THE AREA TO
A WEAK UPPER LOW VCNTY NYC... AT THE SFC...A WEAK RIDGE OF HIGH
PRES WILL XTND SWRD INTO OUR AREA FROM ERN CANADA. BEST UPPER
DYNAMICS WILL REMAIN WELL NE AND SW OF THE AREA BUT JUST ENUF
FORCING ACROSS OUR AREA TO WARRANT SLGT CHC TO LOW CHC POPS W/ BEST
POPS ACROSS SRN/SWRN AREAS FRI NGT INTO SAT AM. THE UPPER TROF IS
PROGGED TO SWING EWRD BUT GUIDANCE SUGGESTS WEAK UPPER SHORT WAVES
CONTG TO SLIDE SSEWRD IN THE NNWRLY FLOW ON THE BACK SIDE OF THIS
TROF WILL ACT TO KEEP THE THREAT OF SHOWERS GOING SAT INTO SAT EVE
ACROSS MAINLY WRN NEW ENGLAND INTO OUR WRN AREAS. WILL CONT W/ SLGT
CHC TO LOW CHC POPS W/ THE HIGHEST OF THESE AGAIN FOCUSED SW. WEAK
SFC HIGH PRES TO STRENGTHEN A BIT ACROSS THE AREA SAT NGT BEFORE LOW
PRES WELL NW OF THE REGION IS FCST DIVE SEWRD TOWARD THE AREA LATE
SUN AND SUN NGT. HIGH TEMPS SAT AND SUN WILL REMAIN JUST A LITTLE
BLO SEASONAL NORMS...
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A GENERALLY UNSETTLED PATTERN TO PERSIST OVER FORECAST AREA THROUGH
WEDNESDAY. A SHORT WAVE EMBEDDED IN PERSISTENT NORTHWESTERLY FLOW
WILL TRACK ACROSS THE FORECAST AREA MONDAY. TOO MUCH UNCERTAINTY
REMAINS TO BE ABLE TO SAY THIS MAY BE FIRST CONVECTIVE OUTBREAK OF
THE SEASON. LONG RANGE MODELS ARE IN FAIR AGREEMENT AT START OF
PERIOD BUT BEGIN TO RAPIDLY DIFFER BY LATE MONDAY. GFS TRACKS MAIN
LOW PRESSURE SOUTH OF THE FORECAST AREA LEADING TO A COOLER
SITUATION WHILE THE ECMWF KEEPS LOW FURTHER NORTH SUGGESTING A
WARM HUMID REGIME AND POSSIBLE THUNDERSTORMS. BASED ON CLIMO AND
CONSENSUS HAVE OPTED TO LEAN TOWARDS GFS AND A COOLER SHOWERY
RESULT. THIS BASIC PATTERN...GENERALLY CLOUDY AND
SHOWERY...PERSISTS THROUGH EARLY WEDNESDAY BEFORE A HINT OF HIGH
PRESSURE BEGINS BUILDING IN WITH PARTLY TO MOSTLY SUNNY SKIES AND
WARMER TEMPS. OVERALL HIGH TEMPS SHOULD REMAIN NEAR AVERAGE WITH
LOWS A FEW DEGREES ABOVE NORMAL DUE TO CLOUD COVER.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: CEILINGS TONIGHT WILL RANGE FROM MVFR THIS EVENING TO
IFR LATE TONIGHT. CEILINGS ON FRIDAY SHOULD IMPROVE TO MVFR IN THE
MORNING AND POSSIBLY VFR BY MIDDAY.
SHORT TERM: EXPECT MAINLY VFR CONDS SAT THRU SUN... MODELS DRIVE
LOW PRES SEWRD FROM VCNTY HUDSON BAY LATER SUN NGT INTO TUE W/
VARYING SOLNS CONCERNING STRENGTH/TIMING OF THIS SYSTEM/SYSTEMS.
WOULD EXPECT MAINLY VFR W/ MVFR TO PSBL BRIEF IFR IN ANY SHOWERS.
CONFIDENCE DURING THIS PERIOD IS LOW...
&&
.MARINE...
NEAR TERM: WINDS AND SEAS WILL REMAIN BELOW SCA TONIGHT AND
FRIDAY. HUMID AIR OVER THE WATERS WILL PRODUCE SOME AREAS OF FOG
MAINLY LATE AT NIGHT AND EARLY FRIDAY MORNING.
SHORT TERM: A WEAK SFC PRES GRADIENT WILL REMAIN ACROSS THE WATERS
SAT THRU SUN RESULTING IN WNDS/SEAS REMAIN BLO SCA LEVELS...
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BLOOMER/FITZSIMMONS
SHORT TERM...KHW
LONG TERM...PJR
AVIATION...BLOOMER/FITZSIMMONS/KHW
MARINE...BLOOMER/FITZSIMMONS/KHW
AREA FORECAST DISCUSSION
NWS DULUTH MN
257 PM CDT THU MAY 22 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 255 PM CDT THU MAY 22 2014
CLOUDS HAVE BEEN VERY SLOW TO DISSIPATE TODAY...HANGING TOUGH FROM
KINL TO KDLH TO KHYR AND KPBH. THE RAP HAS BEEN DOING A DECENT JOB
DEPICTING THESE CLOUDS. COLD TEMPS AND CYCLONIC FLOW ALOFT HAVE
CONTRIBUTED TO A FAVORABLE SET UP FOR THE CLOUDS.
THE CLOUDS HAVE BEEN SLOWLY DIMINISHING THIS AFTERNOON AND WITH
LOSS OF HEATING...WE EXPECT IT TO CONTINUE. THE RAP ALSO SHOWS THE
CLOUDS DIMINISHING THIS EVENING. THE HIGH WILL PASS OVER THE CWA
AND WINDS WILL BECOME LIGHT ALLOWING TEMPS TO COOL INTO THE MID
THIRTIES TO LOWER FORTIES. SOME OF THE COOLER LOCALES ACROSS THE
CWA MAY DROP TO NEAR FREEZING.
AS THE HIGH CONTINUES ITS SLOW EASTWARD TRACK FRIDAY...WINDS WILL COME
AROUND TO MORE SOUTHERLY FOR MOST AREAS. IT SHOULD BE WARMER WITH
MOST AREAS CLIMBING TO 69 TO 75. AREAS AROUND LAKE SUPERIOR WILL BE
COOLER WITH LIGHT ONSHORE WINDS EXPECTED. THERE SHOULD ALSO BE MORE
SUN AS UPPER LEVEL RIDGING AND WARMING TEMPS OCCUR.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 255 PM CDT THU MAY 22 2014
OVERALL SYNOPTIC SCALE PATTERN FEATURES A MID LVL RIDGE OVER NRN
PLAINS AND UPPER MIDWEST NEXT 5 TO 7 DAYS. WITHIN THAT REGIME THERE
IS SOME AGREEMENT AMONGST MED RANGE MDL SUITE THAT A PROGRESSIVE
SHORTWAVE TROF MAY DAMPEN RIDGE ENOUGH TO WARRANT AN EPISODE OF
PRECIP. AS MID LVL RIDGE MOVES INTO REGION THIS WEEKEND WIT WILL BE
ACCOMPANIED BY A BROAD PATTERN OF WARM ADVECTION IN THE LOW/MID
LAYERS. A PROGRESSIVELY MORE MOIST ATMOSPHERE WILL DEVELOP AND THERE
IS A CHC THAT SCTD CONVECTION MAY OCCUR AS EARLY AS SAT AFTN OVER
WRN CWA. HOWEVER WILL ACCEPT MDL TREND TO SLOW DOWN ARRIVAL OF
SUFFICIENT MOISTURE AND START PRECIP POTENTIAL SAT NIGHT. GRADUAL
INCREASE IN POPS SUNDAY WITH HIGHEST PROB OCCURRING SUN NIGHT/EARLY
MONDAY AS LARGE SCALE ASCENT IS MAXIMIZED WITH PASSAGE OF SHORTWAVE
ALOFT. SFC HIGH WILL BUILD SOUTH BEHIND THE DEPARTING SHORTWAVE
MONDAY. SOME TIMING DIFFERENCES WITH REGARD TO HOW SOON THE PRECIP
MOVES SOUTH OF THE CWA. BEYOND THAT UNCERTAINTY INCREASES AS INITIAL
SFC BDRY MOVES WELL SOUTH OF REGION TUESDAY AND THEN POSSIBLY
RETREATS NORTH BY MIDWEEK. ALLBLEND SOLUTION GIVES POPS ACROSS SRN
CWA TUES/WED HOWEVER NOT CONFIDENT THAT ENOUGH MOISTURE IS EVIDENT.
WILL LET NEXT SHIFT SHIFT TO A DRIER PATTERN IF MDL TRENDS CONTINUE.
TEMPS REMAIN ABOVE NORMAL THROUGH PERIOD AS 50H PATTERN ADVERTISES
ANOMALOUS RIDGING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1223 PM CDT THU MAY 22 2014
OTHER THAN A BRIEF PERIOD OF MVFR AT KINL EARLY THIS AFTERNOON
EXPECT VFR THROUGH THE PERIOD AS SFC HIGH PREVAILS. CLOUD DECK
OVER THE REGION WILL SLOWLY DECREASE THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 41 70 46 75 / 0 0 0 10
INL 39 73 50 79 / 0 0 10 10
BRD 42 75 55 79 / 0 0 10 10
HYR 38 75 45 76 / 0 0 0 10
ASX 39 68 43 72 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM...CANNON
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
342 PM CDT THU MAY 22 2014
.SYNOPSIS...
ISSUED AT 342 PM CDT THU MAY 22 2014
THE H5 PATTERN REMAINS LARGELY UNCHANGED FROM 24 HOURS
AGO WITH LITTLE OR NO HT CHANGES NOTED ACROSS THE CONUS. HIGH
PRESSURE WAS ANCHORED OVER SERN ALABAMA...WITH LOW PRESSURE OVER THE
CANADIAN MARITIMES AND A CLOSED LOW OVER THE CALIFORNIA DESERT. WV
IMAGERY THIS AFTERNOON HAS A DECENT SHORTWAVE LIFTING NORTH ACROSS
THE SRN ROCKIES FROM NRN NEW MEXICO INTO SRN COLORADO. ANOTHER
SHORTWAVE WAS LIFTING ACROSS EASTERN UT AND WESTERN WYOMING AS OF
MIDDAY. FURTHER EAST...THE REMNANTS OF A CONVECTIVE COMPLEX WHICH
LIFTED ACROSS SRN NEBRASKA AND NORTHERN KS OVERNIGHT...HAS LIFTED
EAST INTO THE MID MISSISSIPPI VALLEY. AT THE SURFACE...A STATIONARY
FRONT EXTENDED FROM NEAR SAINT LOUIS MO...WSW INTO THE OK
PANHANDLE...THEN NNWD ALONG THE FRONT RANGE OF COLORADO AND WYOMING.
FURTHER NORTH...HIGH PRESSURE HAS MOVED FROM THE DAKOTAS INTO THE
UPPER MISSISSIPPI VALLEY THIS MORNING...WHICH HAS SHIFTED WINDS TO A
MORE SERLY DIRECTION THIS MORNING...AND HAS BEGUN TO PUSH ADDITIONAL
LOW LEVL MOISTURE INTO WESTERN AND NORTH CENTRAL NEBRASKA. AS OF 2
PM CDT...UNDER PARTLY CLOUDY SKIES...TEMPERATURES RANGED FROM 73 TO
75 DEGREES ACROSS WESTERN AND NORTH CENTRAL NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 342 PM CDT THU MAY 22 2014
UPPER LEVEL RIDGE REMAINS PARKED ACROSS MUCH OF THE CENTRAL UNITED
STATES ONCE AGAIN TODAY...EFFECTIVELY IMPEDING THE UPPER FLOW OVER
MUCH OF THE CONUS. WITH THIS BLOCKED FLOW...THE UPPER LEVEL LOW OFF
TO OUR WEST HAS NOT MADE SIGNIFICANT EASTWARD PROGRESS OVER THE PAST
24 HOURS...BUT HAS SLIPPED SOUTH INTO SOUTHERN CALI/NORTHERN BAJA.
THIS SOUTHWARD SHIFT HAS ALLOWED FOR A SLIGHT AMPLIFICATION OF THE
RIDGE INTO THE WESTERN HIGH PLAINS...WHICH IS NOW PROVIDING FOR A
LIGHTER...BUT MORE DIRECT NORTHERLY COMPONENT OF THE STEERING LEVEL
WINDS. AS HAS BEEN THE CASE THE PAST FEW DAYS...THE CONVECTION
ALLOWING MODELS ARE GENERATING CONVECTION NEAR THE FRONT
RANGE/PALMER DIVIDE AND ALONG CONVERGENCE ASSOCIATED WITH A MODEST
DCVZ. WITH TIME THE MODELS INDICATE ADDITIONAL DEVELOPMENT FURTHER
EAST ON THE HIGH PLAINS AS THE ATMOSPHERE CONTINUES TO DESTABILIZE
IN A WEAK LOW LEVEL UPSLOPE REGIME. THIS ACTIVITY IS SHOWN TO SPILL
ONTO THE PLAINS OF FAR SOUTHWEST AND WESTERN NEBRASKA THIS EVENING
DESPITE THE GREATER NORTHERLY TRAJECTORY. THE HRRR HAS HANDLED THE
PAST FEW DAYS WELL ALONG THE FRONT RANGE AND ADJACENT PLAINS...THUS
THE FORECAST THROUGH INTO THE OVERNIGHT WAS TRENDED IN THAT
DIRECTION. WITH THAT...GENERALLY CUT BACK THE EXTENT AND
PROBABILITY OF PRECIP FOR MUCH OF THE CWA...SAVE FOR OUR FAR
SOUTHWEST WHERE THE RAP13 AND HRRR SUGGEST THE PRESENCE OF STORMS
AFTER 03Z. SHOULD STORMS HOLD TOGETHER INTO SOUTHWEST NEBRASKA THIS
EVENING THERE IS SOME SUPPORT OF ELEVATED INSTABILITY WHICH WOULD
PROMOTE A STRONG TO SEVERE STORM OR TWO. OTHERWISE INCREASING
CLOUDS OVERNIGHT WILL HELP KEEP TEMPERATURES MILD...WIDESPREAD LOWS
IN THE MID 50S SEEMS PLAUSIBLE.
FRIDAY...SURFACE HIGH PRESSURE WILL BUILD EAST TOWARD THE GREAT
LAKES REGION...ALLOWING FOR A GREATER SOUTHERLY COMPONENT TO THE
LOWER TROPOSPHERIC FLOW ACROSS THE CWA. WITH INCREASING LOW LEVEL
MOISTURE...SHOWERS AND THUNDERSTORMS WILL FORM WITH A LIFTING
FRONTAL BOUNDARY BY EARLY AFTERNOON. THE CAPPING INVERSION IS WEAK
FRIDAY...SO STORM COVERAGE IS EXPECTED TO BE MORE NUMEROUS...BUT
SEVERE COVERAGE SHOULD BE LIMITED AS NUMEROUS UPDRAFTS COMPETE AND
THE UPPER STEERING FLOW REMAINS WEAK UNDER RIDGING ALOFT.
TEMPERATURES WILL BE MODERATED BY EXPECTED OVERCAST SKIES AND THE
POTENTIAL OF SHOWERS. HIGHS IN THE 70S FOR MOST LOCATIONS SEEMS ON
PAR.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 342 PM CDT THU MAY 22 2014
FRIDAY NIGHT THROUGH MONDAY...FORECASTING CHALLENGES IN
THE MID RANGE CONTINUE TO BE PRECIPITATION CHANCES...AS A PERSISTENT
TROUGH OF LOW PRESSURE ALOFT CREEPS TOWARD THE CENTRAL AND SOUTHERN
PLAINS INTO THE WEEKEND. ONGOING CONVECTION ACROSS NERN COLORADO AND
WESTERN KS...WILL MAKE ITS WAY INTO SOUTHWESTERN AND WESTERN
NEBRASKA FRIDAY EVENING. AS HAS BEEN THE CASE OVER THE PAST SEVERAL
NIGHTS...THIS ACTIVITY IS EXPECTED TO WEAKEN AS IT MOVES EAST INTO
MUCH WEAKER SHEAR ACROSS WESTERN NEBRASKA. CHANCE POPS WERE
CONTINUED IN THE WEST AND SWRN CWA FRIDAY EVENING WITH POPS FALLING
SHARPLY IN THE CENTRAL AND EAST. EVEN WITH DECENT MOISTURE...THE
LACK OF A DECENT LOW LEVEL JET AND WEAK DYNAMICS SHOULD LIMIT THE
COVERAGE OF PCPN FRIDAY NIGHT. MIN TEMPS SATURDAY MORNING...ARE
EXPECTED TO BE MILD IN THE MID AND UPPER 50S GIVEN THE INCREASED LOW
LEVEL MOISTURE...AND EXPECTED LOW LEVEL CLOUD COVER. LOW CLOUDINESS
WILL LINGER INTO SATURDAY WITH THE MODELS INDICATING A CONTINUATION
OF PERSISTENT LOW LEVEL CLOUDINESS INTO SATURDAY AFTERNOON. WITH
AFTERNOON HEATING AND A WEAK CAP IN PLACE...AM EXPECTING SHOWERS AND
THUNDERSTORMS TO DEVELOP...ESPECIALLY OVER SWRN NEBRASKA WHERE
CAPE/S REACH 1000 TO 1500 J/KG SAT AFTERNOON. THIS ACTIVITY IS
EXPECTED TO BE FAIRLY DISORGANIZED THOUGH AS DEEP SHEAR IS VERY WEAK
AT 15 KTS OR LESS SAT AFTN AND SAT EVE. ON SATURDAY NIGHT...THE
FRONTAL BOUNDARY WILL LIFT NORTH INTO SOUTH DAKOTA. BY
SUNDAY...SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS SOUTH DAKOTA
INVOF OF THE FRONT...AIDED BY A SHORTWAVE TROUGH WHICH TRAVERSES THE
NRN TIER OF STATES SUN AFTERNOON. FURTHER SOUTH...SHRAS AND
THUNDERSTORMS WILL DEVELOP ACROSS THE HIGH PLAINS OF WESTERN KANSAS
SOUTH TO THE TX PANHANDLE. IN ADVANCE OF THE MAIN UPPER LEVEL TROUGH
OF LOW PRESSURE. DECIDED TO DROP POPS DOWN A BIT FOR
SUNDAY...PARTICULARLY IN SWRN NEBRASKA...WITH THE BEST FORCING OVER
WRN KS...AND NORTH OF THE FORECAST AREA INVOF THE FRONT. BETTER
CHANCES FOR PCPN WILL ARRIVE IN ALL AREAS SUNDAY NIGHT INTO EARLY
MONDAY AS THE FRONT DROPS SOUTH INTO THE FORECAST AREA.
MONDAY NIGHT THROUGH THURSDAY...THE UPPER LEVEL TROUGH OF LOW
PRESSURE WILL LIFT EAST ACROSS THE SOUTHERN PLAINS MONDAY INTO
MONDAY NIGHT...SHIFTING THE THREAT FOR PCPN EAST. TEMPERATURES WILL
WARM WEDNESDAY AND THURSDAY THANKS TO WEAK LOW AMPLITUDE RIDGING
ACROSS THE ROCKIES. NO DOUBT...WE MAY SEE SOME ISOLATED
THUNDERSTORMS WEDNESDAY AND THURSDAY AHEAD OF AN APPROACHING TROUGH
OF LOW PRESSURE. WITH GUIDANCE POPS WELL BELOW CLIMO...WILL LEAVE
CONDS DRY FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1220 PM CDT THU MAY 22 2014
OR THE 18Z KLBF AND KVTN TAFS...CONVECTION CHANCES CONTINUES TO BE
THE MAIN FORECAST CONCERN TO THE AVIATION COMMUNITY. THE FORECAST
IS EMPLOYING A PERSISTENCE APPROACH CONCERNING THE
CONVECTION...THIS IS BASED OFF THE FACT THAT LITTLE CHANGE IN THE
UPPER PATTERN HAS BEEN NOTED OVER THE PAST 24 HRS. AS SEEN THE PAST
COUPLE DAYS...STORMS WILL INITIATE OFF THE PALMER DIVIDE AND/OR
HIGHER TERRAIN OF EASTERN COLORADO/WYOMING THIS AFTERNOON...THEN
SLOWLY MOVE/BUILD TO THE EAST NORTHEAST THROUGH THE AFTERNOON. THE
CONVECTION ALLOWING SHORT TERM MODELS SEEM TO BE OFF A BIT ON THE
TIMING AND LOCATIONS OF THE FRONT RANGE CONVECTION...AND THUS DOES
DEEMED SUSPECT. BUT THE GENERAL IDEA IS THAT THE EVENTUAL
CONVECTION WILL DRIFT INTO FAR SOUTHWEST NEBRASKA AFTER 00Z THIS
EVENING...POTENTIALLY IMPACTING THE KIML AND KOGA TERMINALS.
THERMODYNAMIC PROFILES DO NOT FAVOR WIDESPREAD SEVERE...BUT A STRONG
STORM OR TWO WOULD BE POSSIBLE. INTO THE OVERNIGHT AND FRIDAY...THE
UPPER LOW RESPONSIBLE FOR THE HIGH PLAINS CONVECTION THE PAST COUPLE
DAYS WILL FINALLY EJECT TO THE SOUTHEAST TOWARD THE SOUTHERN
PLAINS. AS THIS OCCURS A DISTURBANCE IS SHOWN TO ROTATE NORTH
ACROSS THE HIGH PLAINS ALLOWING FOR GREATER COVERAGE OF -TSRA TO
THE REGION. ATTM THE GREATEST COVERAGE BEFORE 18Z WILL BE ACROSS
SOUTHWEST NEBRASKA...POSSIBLY AS FAR NORTH AS KLBF.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JACOBS
LONG TERM...JACOBS
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
107 PM CDT THU MAY 22 2014
.UPDATE...
ISSUED AT 459 AM CDT THU MAY 22 2014
ALREADY SENDING AN UPDATE TO ACCOUNT FOR THE LIFT GENERATING NEW
SHWRS BETWEEN MCK-IML-AKO. THE PUB/GLD RADARS SHOW 25-30 KTS FROM
THE SW AT 5K FT AGL. THE NAM/GFS DO INDICATE ISENTROPIC LIFT WHERE
THESE SHWRS ARE DEVELOPING. NOT SURE HOW MUCH OF THIS WILL HEAD E
INTO THE FCST AREA. SO POPS HAVE BEEN INCREASED THIS MORNING AND
ANTICIPATE FURTHER SHORT-TERM ADJUSTMENTS AS THE MORNING PROCEEDS.
IRONICALLY I USED THE 06Z NAM AS A GUIDE. IF THE NAM TURNS OUT
CORRECT...MAJOR FCST ADJUSTMENTS WILL BE NEEDED LATER THIS
MORNING. WE HAVE NOTED SEVERAL MODELS CAP HIGH TEMPS IN THE UPPER
60S OVER MUCH OF S-CNTRL NEB.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT THU MAY 22 2014
...A DIFFICULT FCST THRU TONIGHT WITH BELOW AVERAGE CONFIDENCE
DUE TO POOR MODEL HANDLING OF THE PLETHORA OF MESOSCALE ASPECTS...
ALOFT: THE LONGWAVES ARE ESSENTIALLY STAGNANT OVER THE CONUS. A
588 SUB-TROPICAL HIGH WAS OVER THE GULF COAST STATES AND WILL
REMAIN THERE THRU TONIGHT. ITS RIDGE AXIS WILL CONT TO EXTEND NW
ACROSS THE CNTRL PLAINS TO MT. THE CUT-OFF LOW OVER NV/CA WILL
MEANDER FURTHER S INTO AZ TONIGHT.
SURFACE: A COOL FRONT REMAINS STALLED W-E ACROSS KS AND WILL
REMAIN IN PLACE THRU AT LEAST TONIGHT. OVERNIGHT TSTM ACTIVITY
WILL STRENGTHEN THE FRONT TODAY. NRN PLAINS HIGH PRES WILL DRIFT
INTO THE WRN GREAT LAKES.
REST OF THIS MORNING: TSTM CLUSTERS WILL CONT EXITING INTO ERN
NEB/KS. CANT COMPLETELY RULE OUT A COUPLE MORE ISOLATED SHWRS/
TSTMS FROM DEVELOPING...BUT THE OVERALL TREND SHOULD BE DRIER.
THIS AGREES WITH THE 03Z HRRR AND 00Z HI-RES WRF RUNS.
QUIET SYNOPTIC REGIMES SUCH AS THIS CREATE MAJOR HEADACHES FOR
FCSTRS. A LOT OF IT COMES DOWN TO INTUITION AS MECHANISMS TO
TRIGGER TSTMS ARE SUBTLE. BUST POTENTIAL IS AT EVERY CORNER FOR
TEMPS/SKY/PRECIP.
TODAY: MOSTLY CLOUDY THIS MORNING WITH LOTS OF CLOUD DEBRIS
AROUND ...BUT IR SATELLITE SHOWS A CLEARING LINE ADVANCING UP FROM
THE TX PANHANDLE. THE TIME-OF-ARRIVAL TOOL BRINGS IT TO OUR SW
COUNTIES BY 830 AM AND TO OUR NE COUNTIES BY 130 PM. SO SKIES
SHOULD TURN PARTLY CLOUDY IF NOT MOSTLY SUNNY THIS AFTERNOON. THIS
BARRING ANY STRATUS THAT MIGHT FORM IN THE PREDAWN HOURS.
BEFORE THE TSTMS FIRED YESTERDAY AFTERNOON...WATER VAPOR IMAGERY
SHOWED WHAT APPEARED TO BE A SHORTWAVE TROF LIFTING FROM NM INTO
THE CNTRL PLAINS. THIS TROF SHOULD ROUND THE RIDGE WITH SUBSIDENCE
TO FOLLOW TODAY. THIS IS PROBABLY WHAT WE ARE SEEING WITH THAT
CLEARING LINE IN SATELLITE.
THE 00Z/06Z NAM CONVECTIVE SCHEMES RE-FIRE TSTMS BY MIDDAY
TODAY...BASICALLY AS SOON AS THE CONVECTIVE TEMP IS REACHED. I
JUST CANNOT SEE THAT HAPPENING IN THE WAKE OF THE DEPARTING TROF.
WOULD EXPECT SOME SUBSIDENCE INVERSION TO RESULT IN AT LEAST A
MODEST CAP. SO THE FCST IS DRY UNTIL 5PM WHEN SLIGHT CHANCE POPS
WERE BROUGHT INTO OUR N-CNTRL KS COUNTIES. HAVE FOLLOWED THE 00Z
WRF RUNS FROM THE NAM... THE NSSL WRF AND THE 07Z/08Z 13 KM RAP
WHICH DO NOT REFIRE CONVECTION.
OTHER MESOSCALE DETAILS: WITH THE HIGH DRIFTING FURTHER E...THE
E-W ORIENTED BAND OF RICH 850 MB MOISTURE ALONG THE FRONT WILL
BEGIN CIRCULATING NW...LIFTING INTO NEB. HOWEVER...SURFACE
DEWPOINTS UPSTREAM OVER IA WERE STILL IN THE MID 40S. SO WHILE IN
SITU DEWPOINTS HAVE RISEN OVERNIGHT...VERY LOW-LEVEL DRY AIR
ADVECTION WILL BE OCCURRING.
ISOLATED TSTMS COULD FIRE ALONG THE CONVECTIVELY REINFORCED WARM
FRONT OVER KS. THIS ACTIVITY COULD LIFT INTO OUR N-CNTRL KS
COUNTIES AND THIS IS WHAT IS FCST BY THE NON-HYDROSTATIC MODELS.
NAM PV IMAGES SHOW A SUBTLE SHORTWAVE TROF EMBEDDED IN THE DRY
SLOT CURRENTLY OVER AZ. MOVEMENT IS NNE AND IT IS FCST TO LIFT
ACROSS NM AND INTO CO TONIGHT. THIS SHOULD TRIGGER THE TSTMS LATE
THIS AFTERNOON AND EVENING OVER THE HIGH PLAINS. WE THEN
ANTICIPATE THIS ACTIVITY TO THREATEN OR MOVE INTO THE FCST AREA
FROM THE SW AGAIN TONIGHT. NO GUARANTEES ON THIS THOUGH. SEVERAL
NON-HYDROSTATIC MODELS KEEP THE FCST AREA DRY. SO POPS WERE KEPT
LOW.
TONIGHT: INCREASING CLOUDS WITH A CHANCE OF SHWRS/TSTMS. GREATEST
CHANCE S AND W OF THE TRI-CITIES. EFFECTIVE SHEAR WILL BE AROUND
30 KTS. WHILE AN ISOLATED SEVERE TSTM IS POSSIBLE OVER N-CNTRL KS
BEFORE MIDNIGHT...IT IS LARGELY BASED ON "IF" TSTMS OCCUR AT ALL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 417 AM CDT THU MAY 22 2014
GUIDANCE SUGGESTS A CLOSED UPPER TROPOSPHERIC LOW WILL EXIST OVER
THE SOUTHWESTERN CONUS AT 12Z FRIDAY. THIS CLOSED LOW IS THEN
EXPECTED TO DRIFT TO THE NORTHEAST AND WEAKEN...EVENTUALLY MOVING
OVER THE CENTRAL PLAINS AS AN OPEN WAVE BY EARLY NEXT WEEK. AT THE
SURFACE SOUTH OR SOUTHEASTERLY FLOW IS EXPECTED TO PERSIST ACROSS
THE AREA THROUGH MUCH OF THE LONG TERM FORECAST PERIOD.
UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE SOUTHWESTERN
UPPER TROPOSPHERIC CLOSED LOW...ALONG WITH MULTIPLE SUBTLE UPPER
TROPOSPHERIC PERTURBATIONS EJECTING FROM THE SOUTHWESTERN
CONUS...WILL CONTINUE TO PROMOTE CHANCES FOR PRECIPITATION ACROSS
THE CWA MOST EVERY DAY DURING THE LONG TERM FORECAST PERIOD. WENT
AHEAD AND TOOK AN EVEN BLEND OF NAM...OPERATIONAL GFS...EC...SREF-
MEAN AND WPC GUIDANCE TO DERIVE QPF GRIDS BOTH FRIDAY AND
SATURDAY...AND THEN DERIVED THE POP GRIDS FROM THESE QPF GRIDS.
AFTER ALL WAS SAID AND DONE...VERY LITTLE CHANGE WAS MADE TO THE
GOING FORECAST. OVERALL...30-60% POPS REMAIN INTACT FOR THE MOST
PART ACROSS THE CWA FRIDAY THROUGH SATURDAY NIGHT. SUNDAY AND
BEYOND...ALLBLEND PROVIDED 20-60% POPS TO VARIOUS PORTIONS OF THE
CWA DURING THE LONG TERM FORECAST PERIOD. THESE POPS WERE LEFT
UNCHANGED FOR THE MOST PART.
CONTINUED SOUTH/SOUTHEASTERLY LOWER TROPOSPHERIC FLOW SHOULD KEEP
INCREASED VALUES OF LOWER TROPOSPHERIC MOISTURE INTACT ACROSS THE
AREA THROUGH EARLY TO MID NEXT WEEK...THUS RESULTING IN 1000-
3000J/KG OF POTENTIAL INSTABILITY EACH AFTERNOON AND EVENING.
ALTHOUGH DEEP-LAYER BULK SHEAR WONT BE ANYTHING TO GET EXCITED
ABOUT...THE MAGNITUDE OF POTENTIAL INSTABILITY ALONE COULD BE
ENOUGH TO PROMOTE STRONG UPDRAFT PRODUCTION CAPABLE OF RESPECTABLE
HAIL SIZE AND PERHAPS DOWN-BURST WIND. THE INHERITED HWO ALREADY
HAD A MENTION OF STRONG STORMS EACH AFTERNOON AND EVENING AND AT
THIS TIME THERE REALLY IS NO REASON TO CHANGE THIS. AS A
RESULT...WENT AHEAD AND MENTIONED THE POSSIBILITY OF STRONG
THUNDERSTORMS EACH AFTERNOON AND EVENING FRIDAY THROUGH NEXT
WEDNESDAY.
LITTLE IF ANY CHANGE IN THE LOWER TROPOSPHERIC AIR MASS WILL
PRESENT SIMILAR TEMPERATURE READINGS FROM DAY TO DAY DURING THE
LONG TERM FORECAST PERIOD...WITH HIGHS GENERALLY IN THE 70S AND
80S AND LOWS IN THE 50S AND 60S CURRENTLY FORECAST.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM CDT THU MAY 22 2014
PREVAILING VFR CONDITIONS ARE EXPECTED AT KGRI THROUGH THE
AFTERNOON HOURS...WITH THUNDERSTROMS EXPECTED TO DEVELOP OVER THE
HIGH PLAINS AND MOVE ACROSS THE REGION OVERNIGHT. DUE TO THE
UNCERTAINTY IN TIMING AND COVERAGE...OPTED TO ONLY INTRODUCE A
VCSH FOR THE TIME BEING. OTHERWISE...OUTSIDE OF ANY
THUNDERSTORMS...WINDS ARE EXPECTED TO BE LIGHT...GENERALLY EAST TO
SOUTHEASTERLY AT 12 KTS OR LESS THROUGH 23/15Z...WHEN THEY WILL
INCREASE A BIT...POTENTIALLY GUSTING TO NEAR 20 KTS TOMORROW
AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1031 AM PDT THU MAY 22 2014
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL CIRCULATE OVER SOUTHERN
NEVADA AND SURROUNDING AREAS THROUGH FRIDAY PRODUCING ISOLATED TO
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. THE SYSTEM WILL
FINALLY MOVE AWAY TO THE EAST SATURDAY...WITH RAIN CHANCES
DIMINISHING AND TEMPERATURES QUICKLY WARMING OVER THE HOLIDAY
WEEKEND.
&&
.UPDATE...QUICK UPDATE TO BUMP UP POPS 10-20 PERCENT OVER CENTRAL
SAN BERNARDINO COUNTY. SHORT RANGE MODELS CONTINUE TO SHOW
INCREASING INSTABILITY OVER THIS AREA AND CONVECTION HAS BEGUN TO
INITIATE OVER THE HIGHER TERRAIN.
&&
.PREV UPDATE...
ISSUED 839 AM PDT THU MAY 22 2014
.PREV UPDATE...A FEW LIGHT SHOWERS ARE ONGOING OVER INYO AND SAN
BERNARDINO COUNTY THIS MORNING. MADE SOME TWEAKS TO THE
SKY/POP/QPF/WX GRIDS THROUGH THIS EVENING BASED OFF THE LATEST
RADAR/SATELLITE IMAGERY AND HIGH-RES MODEL GUIDANCE. I EXPANDED
POPS A BIT FURTHER EAST IN SAN BERNARDINO COUNTY...AND REDUCED THEM
OVER CENTRAL NYE. IN GENERAL THERE IS AT LEAST A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS EAST OF US 95 TODAY...WITH THE
BEST CHANCES OVER THE TERRAIN OF INYO AND SAN BERNARDINO COUNTIES.
WITH LIMITED MOISTURE TO WORK WITH GUSTY WINDS TO 30-40 MPH WILL BE
THE PRIMARY THREAT WITH ANY STORMS TODAY. THERE WILL BE THE
POTENTIAL FOR SOME GUSTS TO AROUND 50 MPH IN SAN BERNARDINO COUNTY.
GENERAL STORM MOTION WILL BE WEST AT 5-10 MPH.
&&
.PREV UPDATE...
ISSUED 632 AM PDT THU MAY 22 2014
.PREV UPDATE...NEEDED TO INCREASE POPS AND CLOUDS ACROSS WESTERN
INYO COUNTY FOR THE REST OF THIS MORNING. NEW TEXT PRODUCTS SENT ON
THE HALF HOUR. NO OTHER CHANGES.
.PREV DISCUSSION...
300 AM PDT THU MAY 22 2014
.SHORT TERM...THROUGH SATURDAY NIGHT...WATER VAPOR SHOWS TWO
DISTINCT WAVES CIRCULATING WITHIN THE TROUGH WHICH HAS CUTOFF FROM
THE WESTERLIES OVER NEVADA/CALIFORNIA. FIRST SHORTWAVE OVER WEST
CENTRAL NEVADA WILL BE MOVING SOUTHWEST THROUGH MONO/NORTHWEST INYO
COUNTIES THIS MORNING. THE LATEST HRRR SPREADS LIGHT SHOWERS SOUTH
THROUGH THE EASTERN SIERRA SLOPES OF INYO AS WELL AS THE NORTHERN
OWEN VALLEY THROUGH 8 OR 9 AM THIS MORNING. SECOND WAVE WAS ALONG
THE SOUTHERN CALIFORNIA COAST HELPING DEEPEN THE MARINE LAYER.
TODAY, MODELS REMAIN IN GOOD AGREEMENT INDICATING MOISTURE AND
INSTABILITY WILL STAY IN THE WESTERN HALF OF THE FORECAST AREA OR
WEST OF LAS VEGAS. AS TROUGH/UPPER LOW SLOWLY SHIFTS FROM SOUTHERN
CALIFORNIA EAST INTO ARIZONA THE PROBABILITIES FOR SHOWERS WILL
FINALLY INCREASE FOR THE HIGHER TERRAIN OF MOHAVE/LINCOLN AND
EASTERN CLARK COUNTIES FRIDAY AND SATURDAY. TO KICK OFF THE HOLIDAY
WEEKEND ON FRIDAY AND SATURDAY TEMPERATURES WILL BE NEAR TO SLIGHTLY
ABOVE NORMAL. ONLY WIND CONCERN OVER THE COMING DAYS WILL BE FROM
THUNDERSTORMS WHERE GUSTS OF 30 TO 40 MPH ARE POSSIBLE.
.LONG TERM...SUNDAY THROUGH THURSDAY NIGHT.
THE MAIN TREND IN THE UPCOMING WEEK APPEARS TO BE A COOLING TREND,
THOUGH HOW BIG OF A COOLING TREND REMAINS UP FOR DEBATE. A
POSITIVELY TILTED MID/UPPER LEVEL RIDGE IS SHOWN TO EXTEND INTO
CALIFORNIA AND NEVADA ON SUNDAY INTO MEMORIAL DAY AHEAD OF AN
INCOMING MID/UPPER LEVEL TROUGH THAT DIGS SOUTH ACROSS THE PAC NW
INTO NORCAL. THE 00Z OPERATIONAL GFS AND TO A LESSER EXTENT THE
SLIGHTLY DRIER ECMWF BOTH SHOW ENOUGH INSTABILITY, CAPE AND
MID-LEVEL MOISTURE ON SUNDAY AFTERNOON OVER THE SOUTHERN SIERRA AND
WHITE MOUNTAINS THAT WE SHOULD SEE AT LEAST SOME CUMULUS BUILD-UPS.
HOWEVER, A FEW SHOWERS OR EVEN A THUNDERSTORM MAY MATERIALIZE AND
POPS WERE INCREASED TO THE 10-15 PERCENT RANGE OVER THESE AREAS FOR
SUNDAY AFTERNOON AND EVENING. BY MONDAY, THINGS LOOK MORE STABLE AS
THE TROUGH APPROACHES, AT THUS THE FORECAST GRIDS ONLY REFLECT
DEVELOPMENT OF CUMULUS IN THE AFTERNOON OVER THESE AREAS. AHEAD OF
THE INCOMING TROUGH, INCREASING SOUTHWEST FLOW WILL ALLOW FOR GOOD
MIXING AND THUS HIGH TEMPS WERE BOOSTED A COUPLE OF DEGREES OVER THE
PREVIOUS FORECAST, ESPECIALLY FOR MEMORIAL DAY BASED ON FORECAST
SOUNDINGS AND STATISTICAL GUIDANCE.
AS WE MOVE INTO THE MIDDLE OF NEXT WEEK, THE TROUGH ALOFT IS
FORECAST TO REMAIN INTO NORCAL WITH A SOUTHWEST FLOW SETTING UP
ACROSS OUR ENTIRE AREA. AS HEIGHTS SLOWLY LOWER AND TEMPS ALOFT
COOL, TEMPS AT THE SURFACE WILL ALSO GRADUALLY DROP A FEW DEGREES
EACH DAY FROM TUESDAY ONWARD, HOWEVER, THEY SHOULD STILL REMAIN AT
LEAST A FEW DEGREES ABOVE NORMAL. THE MOST NOTICEABLE DROP SHOULD BE
IN THE WESTERN CWFA WHERE IT IS POSSIBLE THE SYNOPTIC COOLING ALSO
GETS A LITTLE BOOST FROM ANY MARINE INFLUENCE THAT CAN TRICKLE
THROUGH THE COASTAL RANGE PASSES. OTHERWISE EXPECT DRY CONDITIONS
WITH A FEW CLOUDS AROUND AT TIMES.
&&
.AVIATION...FOR MCCARRAN...WIND SPEEDS UNDER 8 KTS THIS MORNING
WITH AN EASTERLY WIND COMPONENT DEVELOPING THIS AFTERNOON. CLOUDS
DEVELOPING THROUGHOUT THE DAY WITH BASES 10-12 KFT WITH LIGHT
SHOWERS POSSIBLE OVER THE SPRING MOUNTAINS AND SHEEP RANGE THIS
AFTERNOON AND EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...A LOW PRESSURE
SYSTEM WILL BE OVER SOUTHERN CALIFORNIA TODAY. ISOLATED TO SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS CAN BE EXPECTED IN AREAS TO THE
WEST OF LAS VEGAS. CLOUD BASES WILL GENERALLY BE AROUND 8-10
KFT MSL AND WILL LEAD TO PARTIAL MOUNTAIN OBSCURATION OVER THE
SOUTHERN SIERRA.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
UPDATE...WOLCOTT
PREV DISCUSSION...PIERCE/STACHELSKI
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
351 PM EDT THU MAY 22 2014
.SYNOPSIS...
A TROUGH WILL PUSH SOUTH TOWARDS LAKE ERIE OVERNIGHT THEN WEAKEN ON
FRIDAY AS HIGH PRESSURE BUILDS OVER THE CENTRAL GREAT LAKES. THE
HIGH WILL SLOWLY MOVE EAST ACROSS THE REGION THROUGH SUNDAY. AN AREA
OF LOW PRESSURE WILL PULL A COLD FRONT THROUGH THE UPPER GREAT LAKES
ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AN AREA OF LOW LEVEL MOISTURE CAN BE SEEN ON VISIBLE SATELLITE
SPILLING SOUTHEAST ACROSS LAKE ERIE OUT OF ONTARIO. THIS IS LEADING
TO SOME ENHANCEMENT OF THE CU FIELD ACROSS EXTREME NE OH/NW PA.
THERE IS ALSO SOME CIRRUS SPREADING IN FROM THE WEST AROUND THE
RIDGE. THE HIGH CLOUD SHOULD SHIFT TO THE SOUTH THIS EVENING AS THE
UPPER LEVEL TROUGH LOCATED NORTH OF LAKE SUPERIOR PIVOTS SOUTHEAST
TOWARDS LAKE ERIE OVERNIGHT. COLD ADVECTION WILL CONTINUE IN THE LOW
LEVELS WITH A 3-4C COLD POCKET SLIDING SOUTHEAST TO NEAR ERIE PA
BY 12Z FRIDAY. EXPECTING TO SEE A PERIOD OF MOSTLY CLEAR SKIES
EARLY THIS EVENING AS WE LOSE SOME OF THE DIURNAL CLOUD THEN
INCREASING OVERNIGHT WITH THE APPROACHING TROUGH. MODEL QPF AND
SOUNDING BOTH IN SUPPORT OF ENOUGH LOW LEVEL MOISTURE FOR A FEW
SPRINKLES OR EVEN AN ISOLATED SHOWER POSSIBLE IN AN ARC FROM
CLE/CAK/YNG WITH THE CONTINUED COLD ADVECTION OVERNIGHT SO
INCLUDED AN ISOLATED SHOWER IN A FEW AREAS. LOWS WILL BE
CONSIDERABLY COOLER TONIGHT AS TEMPERATURES DIP INTO THE UPPER 40S
TO NEAR 50 DEGREES.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
SKIES WILL BE PARTLY TO MOSTLY CLOUDY(EAST) INTO THE AFTERNOON ON
FRIDAY WITH STEEP LOW LEVEL LAPSE RATES IN PLACE. THE TROUGH IN THE
EAST WILL RELAX THROUGH THE DAY WITH HIGH PRESSURE BUILDING OVER THE
WESTERN LAKES REGION. HIGH TEMPERATURES WILL BE JUST A FEW DEGREES
COOLER THAN TODAY AND MAY NOT ESCAPE THE 50S IN NW PA IF CLOUD ARE
THICK ENOUGH.
THIS AREA OF HIGH PRESSURE WILL BUILD EAST ACROSS THE
REGION BRINGING DRY CONDITIONS THROUGH AT LEAST SUNDAY. DESPITE SOME
LINGERING CU ON SATURDAY...THERE WILL BE A LOT OF SUN OVER THE
WEEKEND WITH GOOD INSULATION. THE PREVAILING NORTHERLY FLOW WILL
WEAKEN GIVING WAY TO JUST AFTERNOON LAKE BREEZES RESULTING IN A
GRADUAL WARM UP. HIGHS WILL RECOVER INTO THE LOW 70S BY SATURDAY AND
MID 70S TO UPPER 70S ON SUNDAY. AREAS CLOSER TO LAKE ERIE WILL
REMAIN A FEW DEGREES COOLER.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THOUGH RAIN CHANCES RETURN LATER IN THE FORECAST THE COVERAGE AND
AMOUNTS EXPECTED SUPPORT AN IMPROVEMENT IN THE SATURATED GROUND
CONDITIONS OF THE LAST FEW WEEKS. FOR MEMORIAL DAY MODELS TRY TO
BRING RAIN TO THE WESTERN COUNTIES LATE. WITH RIDGING ALOFT AND
UPPER LEVEL SHORT WAVE WELL TO THE WEST IT MAY TAKE SOME TIME TO
MATERIALIZE. KEPT CHANCES MINIMAL FOR THE DAY...WITH INCREASING
CHANCES OVERNIGHT INTO TUESDAY. THE LOW PRESSURE SYSTEM WILL MOVE
EAST TUESDAY FOLLOWED ONCE AGAIN BY HIGH PRESSURE. TEMPERATURES WILL
RANGE ON THE WARMER SIDE OF GUIDANCE WITH HIGHS IN THE 80S MONDAY
AND TUESDAY...FALLING TO THE 70S MID TO LAKE WEEK. THE HIGHER DEW
POINTS WILL REMAIN FURTHER SOUTH.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
BEGINNING TO SEE AFTERNOON CU DEVELOP STARTING AROUND 3500`
INCREASING TO AROUND 4500` THROUGH THE AFTERNOON. MOST AREAS WILL
CLEAR OUT WITH LACK OF DIURNAL HEATER...BUT CLOUDS WRAPPING AROUND
THE MIDLEVEL LOW COULD TRACK IN OVER THE ERIE TERMINAL THIS EVENING.
ADDITIONAL MOISTURE WILL MOVE IN TO THE AREA LATE TONIGHT AND EARLY
FRIDAY. MODELS DISAGREEING ON THE AMOUNT OF MOISTURE WITH SOME
SHOWING A BROKEN 5K` DECK WHICH THE RUC SHOWS SCATTERED AT BEST. THE
MOST LIKELY TERMINALS TO SEE THE LOWER CLOUD REDEVELOPMENT WILL
BE THOSE IN THE EAST CLOSER TO THE LOW LIKE YNG/CAK/ERI AND PERHAPS
EVEN CLE. HIGH PRESSURE IS BUILDING IN FROM THE WEST AND SUBSIDENCE
WILL MAKE SUPPORT LESS CLOUDS IN OVER FDY/TOL/MFD.
.OUTLOOK...VFR.
&&
.MARINE...
THE NORTHWESTERLY FLOW WILL BE PREDOMINANT THE NEXT FEW DAYS WITH
SPEEDS 15KT OR LESS. HIGH PRESSURE WILL LINGER OVER THE GREAT LAKES
FOR THE WEEKEND WITH A FRONTAL PASSAGE LATE MONDAY INTO TUESDAY.
WEATHER WILL REMAIN QUIET OVER THE WATERS THROUGH THE FORECAST.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...JAMISON
AVIATION...JAMISON
MARINE...JAMISON
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
116 PM EDT THU MAY 22 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE FORECAST AREA THIS MORNING. LARGE
AREA OF CANADIAN HIGH PRESSURE WILL MOVE SOUTHEAST ACROSS THE GREAT
LAKES...THEN MOVE OFF THE SOUTHEAST COAST LATE SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SKIES HAVE BECOME MOSTLY SUNNY WITH INCREASING SUBSIDENCE BEHIND
THE FRONT THIS MORNING WITH THE ONLY EXCEPTION BEING IN NW PA
WHERE STRATUS CONTINUES TO ERODE. DIURNAL CU IS STARTING TO FILL
IN ACROSS NW OHIO WITH AN AREA OF CLOUDS/HIGHER MOISTURE APPROACHING THE
NORTH SIDE OF LAKE ERIE. THIS WILL RESULT IN SOME INCREASE IN
CU AS WE HEAD TOWARDS LATE AFTERNOON. UNTIL THEN IT LOOKS LIKE
TEMPERATURES FROM CAK-YNG ARE RUNNING A COUPLE DEGREES HIGHER THAN
FORECAST AND NUDGED HIGHS UP A DEGREE OR TWO.
ORIGINAL DISCUSSION... CONVECTION HAS MOVED SOUTH OF THE FORECAST
AREA...THINK THE REMAINDER OF THE DAY SHOULD REMAIN DRY...ALTHOUGH
NOT OUT OF THE QUESTION THAT A STRAY SHRA/TSRA COULD POP UP NEAR
THE FRONTAL BOUNDARY TOWARD DAYBREAK. THE COLD FRONT NOW THROUGH
NORTHWEST OHIO AND ALL MODELS FORECAST IT TO MOVE SOUTH OF THE
AREA BY LATE MORNING. TEMPERATURES WILL BE SLOW TO WARM WITH THE
COOLER AND DRIER AIRMASS MOVING OVER THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
AT THE SURFACE LARGE AREA OF CANADIAN HIGH PRESSURE WILL MOVE
SOUTHEAST ACROSS THE GREAT LAKES THIS WEEKEND PROVIDING DRIER AND
COOLER CONDITIONS. LOW SHOULD BE CENTERED OVER THE AREA BY
SATURDAY EVENING. THAT SAID AT THE UPPER LEVELS A TROUGH WILL SWING
ACROSS EASTERN LAKE ERIE LATE TONIGHT. LEFT CHANCE POPS GOING FOR
EXTREME NE OH AND NW PA.
THE 850 MB TEMPERATURES ARE EXPECTED TO DIP TO AROUND PLUS 4 C BY
FRIDAY MORNING. WITH THE LAKE TEMPERATURE IN THE MID TO UPPER 50S
THAT WILL BE COLD ENOUGH FOR SOME LAKE EFFECT CLOUDS EXTREME NE OH
AND NW PA. EVEN THOUGH THE SURFACE WINDS DO TURN TO THE WEST
FRIDAY...THE UPPER LEVEL FLOW REMAINS FROM THE NW. WILL SEE A
GRADUAL WARMING TREND STARTING SUNDAY AS SURFACE HIGH MOVES EAST OF
THE AREA SETTING UP A SOUTHERLY FLOW.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
NOT MANY CHANCES TO THE LONG TERM TODAY. A WARM AND MOISTENING
AIRMASS WILL BE OVER THE LOCAL AREA AT THE START OF THE PERIOD.
WESTERN AREAS COULD SEE A FEW THUNDERSTORMS BY LATE MONDAY BUT
BETTER CHANCES FOR STORMS WILL COME ON MONDAY NIGHT AND TUESDAY.
THIS ACTIVITY WILL COME IN RESPONSE TO A WEAK LOW PASSING JUST TO
THE NORTH OF THE AREA. BOTH THE LATEST GFS AND ECMWF SHOW THIS
SYSTEM. IT APPEARS EVEN BETTER CHANCES FOR PRECIP WILL BE JUST
NORTH OF THE AREA. HIGH PRESSURE WILL RETURN FOR WEDNESDAY AND WILL
TRY FOR DRY WEATHER. HIGHS MONDAY AND TUESDAY WILL BE AT LEAST 10
DEGREES ABOVE NORMAL WITH SLIGHTLY COOLER READINGS EXPECTED ON
WEDNESDAY.
&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
BEGINNING TO SEE AFTERNOON CU DEVELOP STARTING AROUND 3500`
INCREASING TO AROUND 4500` THROUGH THE AFTERNOON. MOST AREAS WILL
CLEAR OUT WITH LACK OF DIURNAL HEATER...BUT CLOUDS WRAPPING AROUND
THE MIDLEVEL LOW COULD TRACK IN OVER THE ERIE TERMINAL THIS EVENING.
ADDITIONAL MOISTURE WILL MOVE IN TO THE AREA LATE TONIGHT AND EARLY
FRIDAY. MODELS DISAGREEING ON THE AMOUNT OF MOISTURE WITH SOME
SHOWING A BROKEN 5K` DECK WHICH THE RUC SHOWS SCATTERED AT BEST. THE
MOST LIKELY TERMINALS TO SEE THE LOWER CLOUD REDEVELOPMENT WILL
BE THOSE IN THE EAST CLOSER TO THE LOW LIKE YNG/CAK/ERI AND PERHAPS
EVEN CLE. HIGH PRESSURE IS BUILDING IN FROM THE WEST AND SUBSIDENCE
WILL MAKE SUPPORT LESS CLOUDS IN OVER FDY/TOL/MFD.
.OUTLOOK...VFR.
&&
.MARINE...
A COLD FRONT WILL PUSH EAST OF THE LAKE THIS MORNING. W TO NW FLOW
IS EXPECTED BEHIND THE FRONT. DO NOT THINK WINDS OR WAVES WILL GET
HIGH ENOUGH FOR SMALL CRAFT HEADLINES. THE DAY CREW CAN TAKE A
CLOSER LOOK. HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND WITH
MAINLY LIGHT FLOW. THE SURFACE RIDGE WILL PUSH EAST OF THE LAKE BY
LATE SUNDAY WHICH WILL ALLOW SW FLOW TO RETURN. SW FLOW WILL THEN
CONTINUE ON MONDAY. OUTSIDE OF A FEW HOURS THIS MORNING...WINDS THE
ENTIRE PERIOD SHOULD BE UNDER 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DJB
NEAR TERM...DJB
SHORT TERM...DJB/KEC
LONG TERM...KUBINA
AVIATION...SJAMISON
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS NORMAN OK
1248 PM CDT THU MAY 22 2014
.DISCUSSION...
REFER TO THE 18Z AVIATION FORECAST BELOW...
&&
.AVIATION...
EXPECT MOST OF THE CONVECTION ACROSS CENTRAL KANSAS WILL
REMAIN NORTH OF OKLAHOMA. HOWEVER...THE HRRR DEVELOPS
WIDELY SCATTERED CONVECTION THIS AFTERNOON ACROSS NORTHWEST
OKLAHOMA.
STORMS HAVE ALREADY FORMED IN EASTERN NEW MEXICO THIS AFTERNOON
AND ADDITIONAL STORMS SHOULD FORM FARTHER EAST. SOME OF THIS
ACTIVITY MAY MOVE INTO FAR NORTHWEST OKLAHOMA DURING THE MID
TO LATE EVENING. OTHER SHOWERS MAY MOVE INTO FAR WESTERN OKLAHOMA
DURING THE OVERNIGHT/EARLY MORNING.
MAINLY VFR CONDITIONS AND SOUTH WINDS WILL PREVAIL THROUGH
THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1029 AM CDT THU MAY 22 2014/
UPDATE...
OVERALL FORECAST LOOKS PRETTY GOOD... JUST SOME MINOR TWEEKS TO
SHOW CURRENT TRENDS. A FEW SHOWERS/STORMS WILL BE POSSIBLE IN NW
PARTS OF THE FA THROUGH THE AFTERNOON HOURS. TEMPERATURES EXPECTED
TO REACH THE 80S AND LOW 90S THIS AFTERNOON.
MAXWELL
PREV DISCUSSION... /ISSUED 624 AM CDT THU MAY 22 2014/
DISCUSSION...
REFER TO THE 12Z AVIATION FORECAST BELOW...
AVIATION...
SOUTHERLY WINDS WILL INCREASE BY LATE MORNING WITH VFR CIGS
BUILDING INTO PORTIONS OF SOUTHWESTERN AND CENTRAL OKLAHOMA
THROUGH THE AFTERNOON. ISOLD TSRA WILL BUILD OVER THE TX
PANHANDLE...AND MAY AFFECT NORTHWESTERN TERMINALS FROM 00Z ONWARD.
FOR NOW...WILL MENTION VCTS AT KGAG...WHERE CONFIDENCE IS SOMEWHAT
HIGHER IN TSRA THIS EVENING.
PREV DISCUSSION... /ISSUED 329 AM CDT THU MAY 22 2014/
DISCUSSION...
THINKING HAS CHANGED VERY LITTLE REGARDING THE FORECAST THROUGH
THE UPCOMING WEEKEND AND INTO EARLY NEXT WEEK. CURRENTLY...A LARGE
CLOSED LOW CONTINUES TO DRIFT EASTWARD OVER THE SOUTHWEST U.S.
THIS FEATURE WILL SLOWLY BUT SURELY HEAD INTO THE SOUTHERN/CENTRAL
PLAINS REGION OVER THE WEEKEND. BEFORE THAT HAPPENS THOUGH...WE DO
EXPECT AT LEAST ONE MORE WARM DRY DAY OVER THE MAJORITY OF
OKLAHOMA AND NORTH TEXAS. WHILE TEMPERATURES WILL BE NOWHERE NEAR
AS WARM AS YESTERDAY OR THE DAY BEFORE...EXPECT MOST AREAS TO
REACH THE UPPER 80S TO LOW 90S...WHICH COMBINED WITH RELATIVELY
HIGH MOISTURE CONTENT WILL MAKE FOR A RATHER MUGGY THURSDAY.
WHILE A SLIM CHANCE OF SHOWERS/STORMS WILL EXIST TONIGHT...THE
RAIN CHANCES WILL REALLY START TO INCREASE FRIDAY. AS THE UPPER
LOW MEANDERS EASTWARD...AN UPPER DIFFLUENT PATTERN WITHIN LARGE
SCALE SWRLY MID LEVEL FLOW WILL OVERSPREAD THE SOUTHERN
PLAINS...PROMOTING SCATTERED TO NUMEROUS STORMS EACH DAY FROM
FRIDAY THROUGH MONDAY. WITH RATHER WEAK CAPPING...STORMS WILL
INITIATE FAIRLY EARLY EACH DAY AND LINGER INTO THE EVENING BEFORE
DISSIPATING OR WEAKENING OVERNIGHT. ADEQUATE MOISTURE AND MODEST
INSTABILITY MAY YIELD SOME ISOLATED SEVERE WEATHER POTENTIAL
SATURDAY THROUGH MONDAY...MAINLY IN THE FORM OF HAIL AND STRONG
WINDS...BUT WIDESPREAD SEVERE WEATHER APPEARS VERY UNLIKELY WITH
THIS SYSTEM. ONE THING THAT DOES SEEM PROBABLE IS A GOOD AMOUNT OF
RAIN OVER AREAS THAT REALLY NEED IT. WIDESPREAD ONE INCH PLUS
RAINFALL TOTALS SEEM REASONABLE FROM FRIDAY THROUGH EARLY NEXT
WEEK...THOUGH A FEW LOCATIONS MAY SEE 4 INCHES OR MORE OF RAIN
WHEN ALL IS SAID AND DONE.
BY MID TO LATE NEXT WEEK...CONSIDERABLE DISAGREEMENT EXISTS AMONG
LONG RANGE MODELS...THOUGH RAIN CHANCES SHOULD GENERALLY DECREASE
AS THE UPPER LOW DRIFTS INTO THE MISSISSIPPI VALLEY...INDUCING
WEAK NORTHWESTERLY MID LEVEL FLOW ACROSS THE REGION. WEAK/FLAT
RIDING SHOULD ATTEMPT TO BUILD BACK INTO THE SOUTHERN
STATES...ALLOWING FOR THE RETURN OF WARM AND MUGGY CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 70 84 67 85 / 0 40 40 30
HOBART OK 69 83 66 84 / 20 50 40 40
WICHITA FALLS TX 70 85 67 86 / 10 40 30 40
GAGE OK 66 81 63 81 / 40 50 60 40
PONCA CITY OK 68 86 67 86 / 20 40 50 30
DURANT OK 69 87 68 86 / 0 10 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
320 PM EDT THU MAY 22 2014
.SYNOPSIS...
A WARM FRONT WILL DRIFT SLOWLY EAST ACROSS THE SUSQUEHANNA VALLEY
THIS AFTERNOON...SEVERAL HOURS PRIOR TO A COLD FRONT PUSHING
SOUTHEAST ACROSS THE STATE. THESE TWO WEATHER FEATURES WILL
SUPPORT CLUSTERS OF SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHEAST HALF OF THE STATE THIS AFTERNOON. FRIDAY STILL LOOKS
UNSETTLED AS A STRONG UPPER AIR DISTURBANCE ROLLS THROUGH AND
TOUCHES OFF SHOWERS. THE EXTENDED FORECAST IS FOR A GRADUAL
WARMING TREND BEGINNING THIS WEEKEND...DESPITE SOME SHOWERS
LINGERING SATURDAY IN THE POST- FRONTAL NORTHWEST FLOW.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SFC WARM FRONT EXTENDED FROM THE POCONOS...SOUTH TO NEAR KLNS AT
1845Z...WHILE A COLD FRONT WILL DRIFT SLOWLY SE FROM THE
ALLEGHENIES OF NORTHERN AND WESTERN PENN.
THE AIRMASS IN THE WARM SECTOR IS QUITE UNSTABLE WITH MU CAPES AOA
2000 J/KG ACROSS THE MIDDLE AND LOWER SUSQ VALLEY... HELPING TO
JUICE UP NUMEROUS TSRA /SOME WITH SUPERCELL CHARACTERISTICS/
ACROSS.
A BLEND OF THE 06/12Z OPERATIONAL GUIDANCE LINES UP NICELY WITH
WHERE THE CURRENT CONVECTION IS LOCATED /AT THE JUXTAPOSITION OF
A DISTINCT 850 MB THETA-E RIDGE...THE SFC WARM FRONT...AND THE
NOSE OF A 90KT UPPER LEVEL WNWRLY JET/.
LATEST RAP AND NAM SHOWS A SMALL BULLSEYE OF EHI AOA 1.5 M2/S2
INVOF KSEG AND POINTS TO THE EAST WILL SUPPORT THE BEST POTENTIAL
FOR LOCALIZED SVR TSRA WITH POSSIBLE MESOS AS THE CELLS HEAD SE
AND INTO THE BETTER LLVL SHEAR AND INSTABILITY ACROSS THE MIDDLE
SUSQ VALLEY AND SRN POCONOS.
SVR TSRA WATCH NO. 172 IN EFFECT FOR OUR FAR ERN ZONES...AND RUNS
TIL 8 PM EDT.
SFC DEWPOINTS SHOULD START TO SLOWLY DROP ACROSS THE CENTRAL MTNS
AND ALLEGHENY PLATEAU /EVEN PRIOR TO THE MID TO LATE AFTERNOON
CFROPA /AS A MEAN LLVL WESTERLY WIND FRESHENS...AND THE THETA-E
RIDGE IN THE BOUNDARY LAYER SHIFTS EAST TO THE SUSQ VALLEY/.
A MORE DISTINCT DROP IN SFC DEWPOINT TO THE UPPER 40S WILL OCCUR
IN THE WAKE OF THE CFROPA.
TEMPS WILL BE NEAR NORMAL THIS AFTERNOON...TOPPING OUT CLOSE TO
80F THROUGHOUT THE LOWER SUSQ VALLEY. HOWEVER...TEMPS WILL LEVEL
OFF IN THE NW...THEN EVEN DIP A FEW TO SVRL DEG F THROUGH THE
AFTERNOON HOURS AS THE DRIER/COOLER AIR MOVES IN BEHIND THE COLD
FRONT. 8H TEMPS FALL 8C THROUGH THE DAY OVER THE NWRN COS.
ONCE THE SHOWERS/STORMS IN THE EAST PUSH OUT OF THE AREA IN THE
EVENING...THE REST OF THE NIGHT SHOULD BE UNEVENTFUL WITH DRY AIR
AND SUBSIDENCE TAKING OVER. MINS MAY WELL BE CLOSE TO 40F IN BFD
FRI AM.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
CLOUDS AND SHOWERS WILL LIKELY MOVE BACK IN QUICKLY FROM THE NW
DURING LATE MORNING-EARLY AFTN DUE TO THE FAST APPROACH OF A VERY
STRONG TROUGH ALOFT. WHILE IT DOES NOT DEEPEN AS IT MOVES
OVERHEAD...THE 5H HEIGHTS FALL 10DAM. WILL CONTINUE TO PLACE THE
HIGHEST POPS IN THE EAST...BUT THE MOUNTAINS ALWAYS GIVE A LITTLE
BOOST OF LIFT IN THE ALREADY-FAVORABLE STEEP LAPSE RATES.
THEREFORE...WILL NOT DROP POPS FROM ANY LOCATION ON FRI AFTN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
AN UPPER-LEVEL TROUGH CROSSING THE INTERIOR NORTHEAST AND NORTHERN
MID-ATLANTIC STATES WILL LINGER ALONG/OFFSHORE THE EASTERN
SEABOARD THRU SATURDAY. THE UPPER LEVEL TROUGHING AND RELATIVELY
COOL CYCLONIC FLOW ALOFT WILL BE REPLACED BY RISING HEIGHTS
EXPANDING NNEWD IN ADVANCE OF A HIGH-LEVEL RIDGE MIGRATING EWD
ACROSS THE SOUTH-CENTRAL U.S. THE UPPER RIDGE IS FORECAST TO
FLATTEN INTO THE MIDDLE OF NEXT WEEK IN ASSOCIATION WITH SHORTWAVE
ENERGY MOVING THROUGH SOUTHEASTERN CANADA. THE MODELS GENERALLY
AGREE ON THE ABOVE MENTIONED LARGE SCALE PATTERN EVOLUTION...WITH
NOTEWORTHY DIFFERENCES CREEPING INTO DETERMINISTIC SOLUTIONS IN
THE OUTER PERIODS. SPECIFICALLY...THE 21/12Z OPRNL GFS IS MUCH
MORE AGGRESSIVE IN LOWERING HEIGHTS OVER THE NORTHEAST/NEW ENGLAND
STATES BY NEXT WED/THU...WHICH RESULTS IN A SIGNIFICANT SPREAD IN
MEDIUM RANGE X/N GFS AND ECMWF BASED MOS TEMPERATURE GUIDANCE.
A MID-LEVEL ANTICYCLONE BUILDING NORTH/EAST FROM THE LWR MS VLY
WILL FAVOR A MORE TYPICAL EARLY-SUMMER PATTERN WITH STRONG
SIGNALS FOR AN UPWARD TEMPERATURE AND HUMIDITY TREND FROM MEMORIAL
DAY INTO THE MIDDLE OF NEXT WEEK. THE POTENTIAL FLY IN THE
OINTMENT MIGHT BE ANY RING OF FIRE CONVECTION THAT COULD THWART
THE PROJECTED WARMING TREND. IN GENERAL EXPECT A BETTER CHANCE FOR
SHOWERS AND AFTN TSTMS INTO THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
NUMEROUS SHOWERS AND LOCALIZED STG TO SVR TSRA WILL CONTINUE TO
TRACK SE ACROSS THE MID AND LOWER SUSQ VALLEY /AND PTS EAST/
LATE THIS AFTERNOON AND WILL LEAD TO BRIEFLY REDUCED VSBYS AND
CIGS /MAINLY MVFR/ ACROSS THE EASTERN HALF OF PENN.
ELSEWHERE...MOST OF CENTRAL AND WESTERN PENN AIRFIELDS WILL STAY
VFR FOR THE REST OF THE DAY /WITHIN THE WARM SECTOR BETWEEN AN
APPROACHING COLD FRONT...AND THE AFOREMENTIONED WARM FRONT IN THE
FAR EAST/.
STRATOCU ASSOC WITH A POOL OF COLD AIR ALOFT WILL LIKELY WORK
INTO THE NW MTNS TONIGHT. COOLING/MOISTENING BLYR...COMBINED WITH
UPSLOPE FLOW...WILL LIKELY CAUSE CIGS TO FALL TO MVFR LATE TONIGHT
AT KBFD. VFR TO OCNL MVFR BKN-OVC STRATOCU DECK WITH SPREAD ACROSS
AT LEAST THE CENTRAL AND NRN PARTS OF PENN BY LATE FRI MORNING
WITH SCATTERED-NUMEROUS SHOWERS DEVELOPING AS A POTENT UPPER LEVEL
TROUGH APPROACHES FROM THE GLAKES REGION.
.OUTLOOK...
SAT...AM LOW CIGS POSS W MTNS.
SUN...PATCHY AM FOG POSSIBLE.
MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/DANGELO
LONG TERM...STEINBUGL
AVIATION...LAMBERT
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
236 PM MDT THU MAY 22 2014
.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 230 PM MDT THU MAY 22 2014
CURRENT SURFACE MAP PLACES HIGH PRESSURE ACROSS MINNESOTA...WITH
RETURN FLOW ACROSS THE HIGH PLAINS. UPPER LOW CONTINUES TO SPIN
ACROSS THE SOUTHWESTERN U.S. WITH RIDGE AXIS ACROSS THE NORTHERN
PLAINS. MLCAPE AROUND 1000 J/KG ACROSS NORTHEAST WYOMING/FAR
WESTERN SOUTH DAKOTA...HOWEVER WEAK CAP AND LACK OF FORCING HAS
KEPT THUNDERSTORM DEVELOPMENT ACROSS THE BLACK HILLS. MARGINAL
SHEAR FOR ROTATING UPDRAFTS. VERY SLOW STORM MOVEMENT. MAIN
THREAT THROUGH THIS EVENING WILL BE SMALL HAIL AND LOCALLY HEAVY
RAINFALL. LATEST RUN OF THE HRRR KEEPS SOME THUNDERSTORM ACTIVITY
ACROSS NORTHEAST WYOMING/WESTERN SOUTH DAKOTA UNTIL AFTER
MIDNIGHT.
SIMILAR SETUP ACROSS THE AREA FOR FRIDAY. MAIN DIFFERENCE WILL BE
STRONGER SHORTWAVE LIFTING NORTHWARD THROUGH WYOMING/WESTERN
NEBRASKA FRIDAY AFTERNOON. WITH STRONGER FORCING...MORE WIDESPREAD
THUNDERSTORM ACTIVITY FRIDAY AFTERNOON/EVENING. SHEAR A LITTLE
STRONGER...SO A FEW SEVERE HAIL STORMS POSSIBLE. SLOW MOVEMENT AND
HIGH PRECIPITABLE WATER WILL RESULT IN LOCALLY HEAVY RAINFALL.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 230 PM MDT THU MAY 22 2014
SOUTHWEST FLOW ALOFT REMAINS ACROSS THE REGION THIS WEEKEND...WITH
SEVERAL SHORTWAVE DISTURBANCES EJECTING OUT OF A PERSISTENT TROF/CUT
OFF LOW OVER THE WESTERN UNITED STATES. CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL CONTINUE SATURDAY AND SUNDAY...WITH THE POTENTIAL
FOR A FEW STRONG TO SEVERE STORMS EACH DAY. MEDIUM RANGE MODELS
CONTINUE TO SHOW SOMEWHAT GOOD AGREEMENT ON THE TRACK AND TIMING OF
UPPER LOW AS IT FINALLY MOVES FROM THE SOUTHWEST CONUS INTO THE
CENTRAL PLAINS LATE THROUGH THE HOLIDAY WEEKEND. CHANCES FOR PCPN
SHOULD DECREASE ACROSS MUCH OF THE AREA BY MONDAY AS THE LOW TRACKS
SOUTH AND EAST OF THE REGION. CHANCES FOR PCPN COULD INCREASE AGAIN
FOR THE SECOND HALF OF THE WEEK AS FLOW ALOFT RETURNS TO THE
SOUTHWEST. TEMPERATURES WILL BE A BIT ABOVE AVERAGE THROUGH THE
PERIOD...WITH HIGHS IN THE 70S AND LOWER 80S ON THE PLAINS...60S AND
LOWER 70S ACROSS THE BLACK HILLS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 230 PM MDT THU MAY 22 2014
VFR CONDITIONS ARE GENERALLY EXPECTED TONIGHT AND FRIDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS CAN BE EXPECTED THIS EVENING ACROSS
NORTHEAST WY AND FAR WRN SD. SHOWERS AND STORMS ARE AGAIN EXPECTED
FRIDAY AFTERNOON. MVFR CONDITIONS ARE POSSIBLE IN THE VICINITY OF
ANY HEAVIER SHOWERS AND STORMS.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...7
LONG TERM...13
AVIATION...13
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
256 PM EDT THU MAY 22 2014
.SHORT TERM (TONIGHT AND FRIDAY)...
SO FAR THE CAP HAS BEEN EFFECTIVE IN SUPPRESSING DEEP CONVECTION
ACROSS THE REGION. SHOWERS HAVE DEVELOPED IN SRN KY...ALTHOUGH NOT
YET TO THE EXTENT THAT THE HRRR AND RUC HAVE BEEN DEPICTING. ANY
STORMS THAT DEVELOP WILL MOVE SE AND ENCOUNTER PLENTY OF CAPE...SO
THE SEVERE THREAT OF LARGE HAIL AND DAMAGING WINDS
REMAINS...ALTHOUGH COVERAGE OF TSTMS MAY NOT BE MORE THAN
SCATTERED. WILL CARRY CHANCE POPS INTO THE EVENING IN THE PLATEAU
AND CENTRAL VALLEY.
THE RIDGE NEAR THE GULF COAST TODAY WILL SHIFT SOUTHWARD
TOMORROW...AND THE AXIS OF MAX THETA-E AT 850 MB SHIFTS SOUTH AS
WELL. MOST TSTM ACTIVITY TOMORROW WILL BE IN THE SOUTHERN
VALLEY...HOWEVER WITH THE CONTINUED LACK OF UPPER LEVEL SUPPORT AND
LIMITED MOISTURE...POPS WILL REMAIN IN THE CHANCE RANGE. THE CAP
LOOKS WEAKER IN FORECAST SOUNDINGS TOMRROW COMPARED TO TODAY. MLCAPE
WILL AGAIN BE PLENTIFUL...IN THE 3000-3500 J/KG RANGE...SO ANY
STORMS THAT CAN DEVELOP WILL HAVE A LARGE HAIL/DAMAGING WIND
POTENTIAL.
.LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)...
BY FRIDAY NIGHT THE FRONT IS PROGGED TO SHIFT SOUTHWARD INTO
GEORGIA...SOUTH CAROLINA AND ALABAMA WHICH WILL ALLOW MORE STABLE
AIR TO FILTER INTO AREAS NORTH OF THE BOUNDARY. THUS RAIN CHANCES
DIMINISH FRIDAY NIGHT AND SATURDAY. THE FRONT WILL BEGIN MOVING
SLOWLY BACK TO THE NORTH ON SUNDAY AND THE SOUTHERN TN AND
SOUTHWEST NORTH CAROLINA COULD SEE THUNDERSTORMS DEVELOP. THE FRONT
WILL CONTINUE MOVING NORTH OVERNIGHT SUNDAY INTO MONDAY AND BRING
CHANCES FOR THUNDERSTORMS FOR THE ENTIRE FORECAST AREA EACH
AFTERNOON THROUGH THURSDAY.
TEMPERATURES ON SATURDAY WILL WILL GENERALLY RANGE FROM THE MID AND
UPPER 70S TO LOWER 80S. SUNDAY MORNING WILL BE RATHER COOL WITH
TEMPERATURES IN THE 40S AND 50S. THIS WILL BE THE COOLEST PERIOD FOR
THE REMAINDER OF THE WEEKEND INTO NEXT WEEK WHEN OVERNIGHT LOWS WILL
RANGE FROM THE MID 50S TO LOWER 60S AND HIGH TEMPERATURES WILL PUSH
NEAR 90 DEGREES BY WEDNESDAY GENERALLY SOUTH OF I-40. MAX
TEMPERATURES COOL SLIGHTLY BY THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 66 87 59 82 / 20 30 10 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 65 83 56 80 / 30 20 10 0
OAK RIDGE, TN 64 83 56 81 / 30 20 10 0
TRI CITIES AIRPORT, TN 57 78 48 80 / 20 10 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS/AC