Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/18/15
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
951 PM MDT FRI APR 17 2015
.UPDATE...
ISSUED AT 942 PM MDT FRI APR 17 2015
ALTHOUGH ADDITIONAL SHOWERS WILL BE MOVING INTO THE URBAN CORRIDOR
FROM DENVER SOUTHWARD AT THIS TIME...AND THEN INTO FRONT RANGE
FOOTHILLS OVERNIGHT...THE COVERAGE DOES NOT APPEAR TO BE
SUFFICIENT ENOUGH TO CONTINUE WITH THE WINTER STORM
WARNING...THEREFORE IT HAS BEEN CANCELLED. THE WRAP AROUND
SNOWFALL IS EXPECTED TO MOVE INTO THE MOUNTAINS BUT MOST OF THIS
WILL OCCUR ON SATURDAY. HAVE ALSO CANCELLED TORNADO WATCH 69 FOR
OUR NORTHEAST PLAINS. IF SOME CLEARING DOES OCCUR OVERNIGHT THEN
FOG MAY AGAIN RETURN FROM AROUND DENVER EASTWARD...WILL KEEP
PATCHY COVERAGE ALONG THE URBAN CORRIDOR...WITH A BIT MORE
COVERAGE FURTHER EAST.
UPDATE ISSUED AT 613 PM MDT FRI APR 17 2015
LATEST HRRR IS MOVING THE PCPN OVER SERN CO INTO THE PALMER
DIVIDE SHORTLY THEN NORTHWEST INTO THE URBAN CORRIDOR. HAVE
INCREASED THE POPS THIS EVENING. PCPN WILL BE RAIN OR A RAIN/SNOW
MIX. DUE TO THE CONVECTIVE NATURE OF THIS SYSTEM...AREAS OVER THE
PALMER DIVIDE AND THE CHEYENNE RIDGE COULD PICK UP AN INCH OR TWO
OF SNOW. ANY SNOWFALL THAT DEVELOPS ELSEWHERE ALONG THE URBAN
CORRIDOR SHOULD BE AN INCH OR LESS. TORNADO WATCH REMAINS IN
EFFECT FOR MORGAN....WASHINGTON...LOGAN...SEDGWICK AND PHILLIPS
COUNTIES UNTIL MIDNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 124 PM MDT FRI APR 17 2015
UPPER LEVEL LOW CENTERED OVER SOUTH CENTRAL COLORADO WILL SLOWLY
SPIN NORTHEAST ACROSS THE STATE AND END UP OVER THE NORTHEAST CORNER
SATURDAY AFTERNOON. DRIER AIR HAS ROTATED NORTH ACROSS THE AREA THIS
AFTERNOON AND BROUGHT THE WIDESPREAD RAIN AND SNOW TO AN END.
CLEARING DUE TO THE DRIER AIR HAS ALLOWED SOME WARMING. HIRES MODELS
SHOWING SCATTERED CONVECTION FILLING IN DURING THE LATE AFTERNOON
AND EVENING. WILL KEEP SCATTERED TO LIKELY POPS IN THE FORECAST THIS
EVENING FOR THIS. ALREADY CANCELED THE ADVISORY WHERE THE SNOW ENDED
IN PARK COUNTY AND THE PALMER DIVIDE. MAY BE ABLE TO CANCEL THE
WINTER STORM WARNING AS WELL. WILL HOLD OFF FOR NOW AND SEE HOW MUCH
CONVECTION FORMS. OUTSIDE OF CONVECTION...ADDITIONAL SNOWFALL ONCE
THE DRY AIR MOVES THROUGH SHOULD BE LIGHT.
COOLED HIGH TEMPERATURES ARE FEW DEGREES FOR SATURDAY WITH COOL AIR
OVER US FROM THE UPPER LEVEL LOW. NORTHWEST FLOW BEHIND THE LOW
COMBINED WITH STEEP LAPSE WILL PRODUCE SNOW SHOWERS OVER THE
MOUNTAINS. INCREASED POPS FOR THIS. NEW SNOWFALL FOR THE MOUNTAINS
SATURDAY WILL GENERALLY BE LESS THAN 4 INCHES...THOUGH A FEW FAVORED
OROGRAPHIC AREAS COULD SEE A LITTLE MORE. FOR THE FRONT
RANGE...DOWNSLOPE FLOW WILL LIMIT PRECIPITATION CHANCES...THOUGH IT
SHOULD BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. THE BEST CHANCE WILL BE OVER THE PLAINS CLOSER TO THE
LOW AND AWAY FROM DOWNSLOPE. AIRMASS WILL BE WARM ENOUGH FOR RAIN
SATURDAY WITH SNOW CONFINED TO THE FOOTHILLS AND MOUNTAINS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 124 PM MDT FRI APR 17 2015
THE ACTIVE PATTERN CONTINUES THROUGH THE WEEKEND AND INTO EARLY
NEXT WEEK. SATURDAY NIGHT INTO SUNDAY THE UPPER LEVEL LOW CENTER
WILL MAKES ITS WAY EAST OVER THE CO AND KS BORDER. THIS WILL BRING
INCREASED NORTHERLY FLOW OVER NE COLORADO WITH A TROUGH OVER THE
WEST WILL HELP BRING A SURGE OF COOLER AIR THAT WILL SPREAD SNOW
SHOWERS OVER THE MOUNTAINS AND FOOTHILLS. THE TROUGH WILL PUSH
EAST HELPING TO DRY OUT THE PLAINS KEEPING THE REGION COOLER UNDER
MOSTLY CLOUDY SKIES. TEMPERATURES FOR SUNDAY WILL CONTINUE TO BE
BELOW SEASONAL NORMALS WITH HIGHS IN THE UPPER 40S TO LOWER 50S.
SUNDAY NIGHT INTO MONDAY STRONG NW WILL PREVAIL WITH A NW ORIENTED
JET MOVING INTO NE COLORADO. INCREASED MOISTURE IN THE MID LEVELS
WITH A SURFACE TROUGH WILL HELP TO KEEP SNOW IN THE MOUNTAINS AND
SCATTERED RAINSHOWERS OVER THE PLAINS THROUGH MONDAY NIGHT INTO
TUESDAY MORNING. WILL KEEP A SLIGHT CHANCE WITH THIS SYSTEM WITH A
CHANCE IN THE MOUNTAINS WITH DECENT ASCENT. TEMPERATURES FOR
MONDAY AND TUESDAY WILL SLOWLY INCREASE TO SEASONAL NORMALS BY
TUESDAY AFTERNOON AS THE UPPER LEVEL RIDING MOVES IN ALONG WITH
SURFACE HIGH PRESSURE. DOWNSLOPING WINDS OFF THE FOOTHILLS WILL
HELP TO WARM TEMPERATURES OVER THE PLAINS INTO WEDNESDAY WHERE
MODELS HAVE HIGH TEMPERATURES REACHING INTO THE UPPER 60S AND
LOWER 70S.
UPPER LEVEL FLOW TURNS SOUTHWESTERLY AHEAD OF THE NEXT DISTURBANCE
OVER SOUTHERN CA. THE MODELS DIVERGE AT THIS POINT WITH THE GFS
BRINGING PRECIPITATION BACK INTO THE MOUNTAINS BY WEDNESDAY
EVENING AND THE EC 24 HOURS BEHIND. WILL KEEP A SLIGHT CHANCE IN
THE GRIDS OR THIS PERIOD BUT WILL CONTINUE TO MONITOR MODEL
TRENDS.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 942 PM MDT FRI APR 17 2015
A MIX OF RAIN AND SNOW SHOWERS MOVING THROUGH DENVER AT THIS
TIME...MVFR WITH THE POTENTIAL FOR IFR CIGS/VSBYS AT KAPA SHORTLY
AND KBJC IN ANOTHER HOUR OR TWO. DURATION FOR THE IFR CONDITIONS SHOULD
BE A LITTLE SHORTER AT KDEN. POTENTIAL FOR FOG DOES EXIST EARLY
SATURDAY MORNING...12Z-15Z...SO WL KEEP THIS POSSIBILITY IN THE
TAFS AS WELL. CONVECTION MAY BE PRODUCING VARIABLE WINDS FOR A
TIME...BUT SHOULD SETTLE ON A LIGHT WNWLY WIND COMPONENT AFTER 06Z
AND THIS SHOULD CONTINUE INTO SATURDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...COOPER
SHORT TERM...MEIER
LONG TERM...BOWEN
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
926 PM MDT FRI APR 17 2015
.UPDATE...
ISSUED AT 919 PM MDT FRI APR 17 2015
UPDATED TO MODIFY POPS BASED ON 00Z GUIDANCE...FOCUSING
HIGHEST CHANCES OVER THE PIKES PEAK REGION AND UPPER ARKANSAS
AND CONTDVD NORTH OF GHWY 50. CUT BACK ON POPS TO THE SOUTH BUT
WILL LEAVE ISOLD-SCT CHANCES OUT FOR THE HIGHER TERRAIN WITH THE
UPPER LOW OVERHEAD.
UPDATE ISSUED AT 844 PM MDT FRI APR 17 2015
MADE SOME ADJUSTMENTS TO THE WINTER HEADLINES BASED ON
OBS...TRENDS AND LATEST MODEL GUIDANCE. LOOKS LIKE THE HEAVIEST
AND MOST PERSISTENT PRECIP WILL BE OVER THE MTS NORTH OF HGWY
50 TONIGHT AND TOMORROW. SO...HAVE CANCELED THE ADVISORIES FOR THE
SANGRES AND WETS. EXTENDED PIKES PEAK AND THE SAWATCH TIL 00Z SUN
SINCE IT LOOKS LIKE PERIODS OF MODT SNOW WILL CONTINUE TOMORROW.
TELLER MAY ALSO HAVE TO BE EXTENDED BUT GIVEN THE UNCERTAINTIES
IN HOW THE BAND OF SNOW NORTH OF THE UPPER LOW WILL SET
UP...WILL LEAVE THE ENDING TIME FOR SAT MORNING FOR NOW. HRRR HAS
MOST OF THE HEAVIER QPF NORTH OF TELLER WHILE THE RAP AND NAM
HAVE IT DIRECTLY OVER TELLER. SO...AMOUNTS ARE MOST UNCERTAIN
OVER THE PIKES PEAK AREA BUT THE GOING ADVISORY COVERS THAT
HAZARD FOR NOW. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 256 PM MDT FRI APR 17 2015
CURRENTLY...THE UPPER LOW IS LOCATED OVER THE SW QUAD OF THE STATE
THIS AFTERNOON...AND WAS WRAPPING DRY AIR UP INTO PORTIONS OF SOUTH
CENTRAL AND SOUTHEAST CO EFFECTIVELY SHUTTING OFF PCPN AND EVEN
CLOUD COVER FOR PORTIONS OF THE CWA. BEFORE THE DRY AIR MOVED
IN...HEAVY SNOW WAS REPORTED OVER MANY OF THE AREA MTS AS WELL AS
THE UPPER ARKANSAS RIVER BASIN...ALONG WITH SIGNIFICANT RAINFALL
AMOUNTS ALL ALONG THE I25 CORRIDOR. CLOUD ENHANCEMENT WAS OCCURRING
AS OF 3 PM OVER THE S MTS...SLOWLY SPREADING NORTH. FARTHER
EAST...DRY AIR PUSHED INTO THE SE CORNER OF THE STATE AND HELPED TO
PUSH THE SEVERE THREAT N AND NE. A FEW THUNDERSTORMS HAVE STRUGGLED
ACROSS THE PLAINS THIS AFTN AS LOWER DEWPOINTS HAVE ROBBED LLVL
ENERGY.
TONIGHT AND TOMORROW...THE MAIN QUESTION IS WHERE WILL THE UPPER LOW
GO. MODELS STILL INDICATE THAT IT WILL GRADUALLY MOVE NORTH INTO
CENTRAL COLORADO THIS EVENING...THEN EDGE DUE EAST THROUGH TOMORROW
AFTN. AFTER A BRIEF LULL...WHICH WILL MOST LIKELY HAVE CUSTOMERS
SCRATCHING THEIR HEADS...ALL MODELS INCLUDING THE HI-RES OFFERINGS
SHOW SHOWERS REDEVELOPING OVER THE PALMER DVD AND RAMPART RANGE...AS
WELL AS THE CENTRAL MTS...N SANGRES AND WETS...THIS EVENING AND
OVERNIGHT. ADDITIONAL SNOW AMOUNTS DO NOT LOOK AS SIGNIFICANT NOW AS
THEY DID 12 HRS AGO...AND HANDLING OF THE HIGHLIGHTS WAS
EXCEPTIONALLY TRICKY. DECIDED TO PUSH ALL ENDING TIMES OF HIGHLIGHTS
TO 12Z TOMORROW MORNING...AND CONVERTED SOME OF THE ONGOING WARNINGS
TO ADVISORIES. FURTHER ADJUSTMENTS TO THE POP AND HIGHLIGHT GRIDS
WILL OCCUR UNDOUBTEDLY. AS FOR TEMPS...FRESH SNOW COVER FOR MUCH OF
THE HIGHER TERRAIN AND HIGH VALLEYS WILL MAKE FOR A COLD NIGHT...AS
WELL AS MODIFYING THE MAX TEMP TOMORROW DOWNWARD A FEW DEGREES. LOOK
FOR MAX TEMPS TOMORROW IN THE 40S TO NEAR 50 F FOR THE HIGH
VALLEYS...50S TO LOWER 60S FOR THE E PLAINS...WITH AREAS THAT
RECEIVED EXTENSIVE SNOW COVER ON THE LOWER END. MOORE
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 256 PM MDT FRI APR 17 2015
OLD UPPER LOW OPENS UP AND PULLS AWAY TO THE EAST SAT NIGHT/SUNDAY.
ANOTHER LOBE OF ENERGY ROTATING AROUND THE BACK SIDE OF THE UPPER
LOW WILL SPREAD ANOTHER BAND OF SNOW SHOWERS INTO THE MTS/PALMER
DIVIDE SATURDAY EVENING...AND INTO THE SOUTHEAST PLAINS SAT
NIGHT/EARLY SUNDAY MORNING. OVERALL ACCUMULATIONS DO NOT LOOK LIKE
THEY WILL BE THAT HEAVY...BUT A COUPLE INCHES ACROSS THE CENTRAL
MTS AND PIKES PEAK REGION WILL BE POSSIBLE...WITH 1-2 ACROSS THE
PALMER DIVIDE. IT WILL BE SOMEWHAT UNSTABLE...SO THERE IS ALWAYS A
CHANCE FOR SOME LOCALLY HEAVY BURSTS OF SNOW...BUT THINK THESE
SHOULD BE FAIRLY LOCALIZED. MEANWHILE PRECIPITATION WILL FALL AS
RAIN ACROSS THE SE PLAINS EARLY BEFORE DIMINISHING BY LATE SUN
MORNING. WINDS REALLY INCREASE ACROSS THE AREA FOR SUNDAY BEHIND
THE SYSTEM WITH NORTH WINDS GUSTING TO 40 TO 50 MPH ACROSS THE
PLAINS. FORTUNATELY MANY PLACES HAVE HAD SOME RAIN...WHICH SHOULD
MINIMIZE BLOWING DUST CONCERNS SOME...AND COOLER AIR BEHIND THE
SYSTEM SHOULD KEEP RELATIVE HUMIDITY VALUES FROM REACHING CRITICAL
LEVELS WHICH SHOULD MITIGATE ANY FIRE WEATHER CONCERNS.
NORTHWEST FLOW KEEPS UNSETTLED WEATHER OVER THE REGION FOR MONDAY
AND TUESDAY WITH PRIMARILY AFTERNOON AND EVENING SNOW SHOWERS OVER
THE MOUNTAINS. ANOTHER REINFORCING NORTHERLY SURGE MOVES THROUGH THE
PLAINS ON MONDAY WHICH WILL ENHANCE EASTERLY UPSLOPE FLOW INTO THE
SOUTHEAST MOUNTAINS. THIS WILL RESULT IN SCATTERED SNOW SHOWERS AS
ANOTHER SHORTWAVE MOVES THROUGH NW FLOW ALOFT. GFS SPREADS THESE
SHOWERS EASTWARD ONTO THE PLAINS DURING THE EVENING HOURS THOUGH
PRECIPITATION WILL FALL MAINLY AS RAIN. WESTERN U.S UPPER RIDGE
TRANSLATES EASTWARD FOR TUESDAY WITH SHOWERS STAYING MORE CONFINED
TO THE MOUNTAINS. AGAIN...MAINLY LIGHT ACCUMULATIONS EXPECTED.
ANOTHER TROF MOVES INTO THE WESTERN U.S FOR THE LATTER PART OF THE
WEEK. UPPER RIDGE AXIS SHIFTS OVER CO FOR WEDNESDAY...THEN
GRADUALLY INTO THE PLAINS THURS AND FRI AS THE UPPER TROF MOVES
TOWARDS THE GREAT BASIN. LOTS OF VARIABILITY BETWEEN THE LONG RANGE
MODELS ON TIMING...BUT BOTTOM LINE IS FOR INCREASING SOUTHWEST FLOW
FOR THURSDAY AND FRIDAY...SPREADING A CHANCE OF SNOW SHOWERS INTO
THE CONTDVD REGION BY LATE WEEK. TEMPERATURES REBOUND ACROSS THE
PLAINS...THOUGH SOUTHEAST FLOW ADVECTS HIGHER DEW POINTS INTO THE
PLAINS BRINGING A CHANCE FOR THUNDERSTORMS. AS SOUTHWEST FLOW ALOFT
INCREASES...THIS SHOULD HELP DEVELOP A DRY LINE AND PUSH IT EASTWARD
ACROSS THE PLAIN...WITH THUNDERSTORMS POSSIBLE ALONG AND TO ITS EAST
THURS AFTERNOON. WILL HAVE TO WATCH THIS DEVELOPMENT AS DEEP
LAYER SHEAR LOOKS FAVORABLE FOR STRONG TO SEVERE THUNDERSTORMS...IF
SUFFICIENT MOISTURE CAN RETURN...BUT GIVEN THE UNCERTAINTIES IN
THE EVOLUTION OF THE SYSTEM...THESE DETAILS ARE LIKELY TO EVOLVE
OVER THE NEXT SEVERAL DAYS. -KT
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 256 PM MDT FRI APR 17 2015
DRY AIR HAS SPREAD IN ACROSS SOUTHERN AND EASTERN
PORTIONS OF THE DISTRICT AROUND THE SOUTHERN AND EASTERN PERIPHERY
OF THE UPPER LOW. THIS WILL KEEP VFR CONDITIONS AT THE TAF SITES. ISOLATED
INSTABILITY SHOWERS WILL BE POSSIBLE IN THE VCNTY OF THE TAF
SITES...THOUGH THESE WILL BE FAIRLY SPOTTY AND IF THEY DO IMPACT
THE TERMINALS..WILL GENERALLY DO SOME BEFORE 03Z. WINDS WILL SHIFT
OUT OF THE NORTH AT KCOS AND KPUB DURING THE EVENING HOURS AT
AROUND 10-15 KTS...THEN BECOME LIGHT OVERNIGHT. WINDS ON SATURDAY
WILL REMAIN NORTHERLY FOR ALL THREE TERMINALS AS THE UPPER LOW
PULLS AWAY TO THE EAST. ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE
ACROSS THE MOUNTAINS. KCOS MAY SEE ANOTHER PASSING SHOWER IN THE
VCNTY OF THE TERMINAL SAT AFTN...WHILE KPUB AND KALS HAVE A
GREATER LIKELIHOOD OF STAYING DRY. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-063-
066-081.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT SATURDAY FOR COZ058-060-
061.
WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR COZ082.
&&
$$
UPDATE...ROSE
SHORT TERM...MOORE
LONG TERM...KT
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
849 PM MDT FRI APR 17 2015
.UPDATE...
ISSUED AT 844 PM MDT FRI APR 17 2015
MADE SOME ADJUSTMENTS TO THE WINTER HEADLINES BASED ON
OBS...TRENDS AND LATEST MODEL GUIDANCE. LOOKS LIKE THE HEAVIEST
AND MOST PERSISTENT PRECIP WILL BE OVER THE MTS NORTH OF HGWY
50 TONIGHT AND TOMORROW. SO...HAVE CANCELED THE ADVISORIES FOR THE
SANGRES AND WETS. EXTENDED PIKES PEAK AND THE SAWATCH TIL 00Z SUN
SINCE IT LOOKS LIKE PERIODS OF MODT SNOW WILL CONTINUE TOMORROW.
TELLER MAY ALSO HAVE TO BE EXTENDED BUT GIVEN THE UNCERTAINTIES
IN HOW THE BAND OF SNOW NORTH OF THE UPPER LOW WILL SET
UP...WILL LEAVE THE ENDING TIME FOR SAT MORNING FOR NOW. HRRR HAS
MOST OF THE HEAVIER QPF NORTH OF TELLER WHILE THE RAP AND NAM
HAVE IT DIRECTLY OVER TELLER. SO...AMOUNTS ARE MOST UNCERTAIN
OVER THE PIKES PEAK AREA BUT THE GOING ADVISORY COVERS THAT
HAZARD FOR NOW. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 256 PM MDT FRI APR 17 2015
CURRENTLY...THE UPPER LOW IS LOCATED OVER THE SW QUAD OF THE STATE
THIS AFTERNOON...AND WAS WRAPPING DRY AIR UP INTO PORTIONS OF SOUTH
CENTRAL AND SOUTHEAST CO EFFECTIVELY SHUTTING OFF PCPN AND EVEN
CLOUD COVER FOR PORTIONS OF THE CWA. BEFORE THE DRY AIR MOVED
IN...HEAVY SNOW WAS REPORTED OVER MANY OF THE AREA MTS AS WELL AS
THE UPPER ARKANSAS RIVER BASIN...ALONG WITH SIGNIFICANT RAINFALL
AMOUNTS ALL ALONG THE I25 CORRIDOR. CLOUD ENHANCEMENT WAS OCCURRING
AS OF 3 PM OVER THE S MTS...SLOWLY SPREADING NORTH. FARTHER
EAST...DRY AIR PUSHED INTO THE SE CORNER OF THE STATE AND HELPED TO
PUSH THE SEVERE THREAT N AND NE. A FEW THUNDERSTORMS HAVE STRUGGLED
ACROSS THE PLAINS THIS AFTN AS LOWER DEWPOINTS HAVE ROBBED LLVL
ENERGY.
TONIGHT AND TOMORROW...THE MAIN QUESTION IS WHERE WILL THE UPPER LOW
GO. MODELS STILL INDICATE THAT IT WILL GRADUALLY MOVE NORTH INTO
CENTRAL COLORADO THIS EVENING...THEN EDGE DUE EAST THROUGH TOMORROW
AFTN. AFTER A BRIEF LULL...WHICH WILL MOST LIKELY HAVE CUSTOMERS
SCRATCHING THEIR HEADS...ALL MODELS INCLUDING THE HI-RES OFFERINGS
SHOW SHOWERS REDEVELOPING OVER THE PALMER DVD AND RAMPART RANGE...AS
WELL AS THE CENTRAL MTS...N SANGRES AND WETS...THIS EVENING AND
OVERNIGHT. ADDITIONAL SNOW AMOUNTS DO NOT LOOK AS SIGNIFICANT NOW AS
THEY DID 12 HRS AGO...AND HANDLING OF THE HIGHLIGHTS WAS
EXCEPTIONALLY TRICKY. DECIDED TO PUSH ALL ENDING TIMES OF HIGHLIGHTS
TO 12Z TOMORROW MORNING...AND CONVERTED SOME OF THE ONGOING WARNINGS
TO ADVISORIES. FURTHER ADJUSTMENTS TO THE POP AND HIGHLIGHT GRIDS
WILL OCCUR UNDOUBTEDLY. AS FOR TEMPS...FRESH SNOW COVER FOR MUCH OF
THE HIGHER TERRAIN AND HIGH VALLEYS WILL MAKE FOR A COLD NIGHT...AS
WELL AS MODIFYING THE MAX TEMP TOMORROW DOWNWARD A FEW DEGREES. LOOK
FOR MAX TEMPS TOMORROW IN THE 40S TO NEAR 50 F FOR THE HIGH
VALLEYS...50S TO LOWER 60S FOR THE E PLAINS...WITH AREAS THAT
RECEIVED EXTENSIVE SNOW COVER ON THE LOWER END. MOORE
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 256 PM MDT FRI APR 17 2015
OLD UPPER LOW OPENS UP AND PULLS AWAY TO THE EAST SAT NIGHT/SUNDAY.
ANOTHER LOBE OF ENERGY ROTATING AROUND THE BACK SIDE OF THE UPPER
LOW WILL SPREAD ANOTHER BAND OF SNOW SHOWERS INTO THE MTS/PALMER
DIVIDE SATURDAY EVENING...AND INTO THE SOUTHEAST PLAINS SAT
NIGHT/EARLY SUNDAY MORNING. OVERALL ACCUMULATIONS DO NOT LOOK LIKE
THEY WILL BE THAT HEAVY...BUT A COUPLE INCHES ACROSS THE CENTRAL
MTS AND PIKES PEAK REGION WILL BE POSSIBLE...WITH 1-2 ACROSS THE
PALMER DIVIDE. IT WILL BE SOMEWHAT UNSTABLE...SO THERE IS ALWAYS A
CHANCE FOR SOME LOCALLY HEAVY BURSTS OF SNOW...BUT THINK THESE
SHOULD BE FAIRLY LOCALIZED. MEANWHILE PRECIPITATION WILL FALL AS
RAIN ACROSS THE SE PLAINS EARLY BEFORE DIMINISHING BY LATE SUN
MORNING. WINDS REALLY INCREASE ACROSS THE AREA FOR SUNDAY BEHIND
THE SYSTEM WITH NORTH WINDS GUSTING TO 40 TO 50 MPH ACROSS THE
PLAINS. FORTUNATELY MANY PLACES HAVE HAD SOME RAIN...WHICH SHOULD
MINIMIZE BLOWING DUST CONCERNS SOME...AND COOLER AIR BEHIND THE
SYSTEM SHOULD KEEP RELATIVE HUMIDITY VALUES FROM REACHING CRITICAL
LEVELS WHICH SHOULD MITIGATE ANY FIRE WEATHER CONCERNS.
NORTHWEST FLOW KEEPS UNSETTLED WEATHER OVER THE REGION FOR MONDAY
AND TUESDAY WITH PRIMARILY AFTERNOON AND EVENING SNOW SHOWERS OVER
THE MOUNTAINS. ANOTHER REINFORCING NORTHERLY SURGE MOVES THROUGH THE
PLAINS ON MONDAY WHICH WILL ENHANCE EASTERLY UPSLOPE FLOW INTO THE
SOUTHEAST MOUNTAINS. THIS WILL RESULT IN SCATTERED SNOW SHOWERS AS
ANOTHER SHORTWAVE MOVES THROUGH NW FLOW ALOFT. GFS SPREADS THESE
SHOWERS EASTWARD ONTO THE PLAINS DURING THE EVENING HOURS THOUGH
PRECIPITATION WILL FALL MAINLY AS RAIN. WESTERN U.S UPPER RIDGE
TRANSLATES EASTWARD FOR TUESDAY WITH SHOWERS STAYING MORE CONFINED
TO THE MOUNTAINS. AGAIN...MAINLY LIGHT ACCUMULATIONS EXPECTED.
ANOTHER TROF MOVES INTO THE WESTERN U.S FOR THE LATTER PART OF THE
WEEK. UPPER RIDGE AXIS SHIFTS OVER CO FOR WEDNESDAY...THEN
GRADUALLY INTO THE PLAINS THURS AND FRI AS THE UPPER TROF MOVES
TOWARDS THE GREAT BASIN. LOTS OF VARIABILITY BETWEEN THE LONG RANGE
MODELS ON TIMING...BUT BOTTOM LINE IS FOR INCREASING SOUTHWEST FLOW
FOR THURSDAY AND FRIDAY...SPREADING A CHANCE OF SNOW SHOWERS INTO
THE CONTDVD REGION BY LATE WEEK. TEMPERATURES REBOUND ACROSS THE
PLAINS...THOUGH SOUTHEAST FLOW ADVECTS HIGHER DEW POINTS INTO THE
PLAINS BRINGING A CHANCE FOR THUNDERSTORMS. AS SOUTHWEST FLOW ALOFT
INCREASES...THIS SHOULD HELP DEVELOP A DRY LINE AND PUSH IT EASTWARD
ACROSS THE PLAIN...WITH THUNDERSTORMS POSSIBLE ALONG AND TO ITS EAST
THURS AFTERNOON. WILL HAVE TO WATCH THIS DEVELOPMENT AS DEEP
LAYER SHEAR LOOKS FAVORABLE FOR STRONG TO SEVERE THUNDERSTORMS...IF
SUFFICIENT MOISTURE CAN RETURN...BUT GIVEN THE UNCERTAINTIES IN
THE EVOLUTION OF THE SYSTEM...THESE DETAILS ARE LIKELY TO EVOLVE
OVER THE NEXT SEVERAL DAYS. -KT
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 256 PM MDT FRI APR 17 2015
DRY AIR HAS SPREAD IN ACROSS SOUTHERN AND EASTERN
PORTIONS OF THE DISTRICT AROUND THE SOUTHERN AND EASTERN PERIPHERY
OF THE UPPER LOW. THIS WILL KEEP VFR CONDITIONS AT THE TAF SITES. ISOLATED
INSTABILITY SHOWERS WILL BE POSSIBLE IN THE VCNTY OF THE TAF
SITES...THOUGH THESE WILL BE FAIRLY SPOTTY AND IF THEY DO IMPACT
THE TERMINALS..WILL GENERALLY DO SOME BEFORE 03Z. WINDS WILL SHIFT
OUT OF THE NORTH AT KCOS AND KPUB DURING THE EVENING HOURS AT
AROUND 10-15 KTS...THEN BECOME LIGHT OVERNIGHT. WINDS ON SATURDAY
WILL REMAIN NORTHERLY FOR ALL THREE TERMINALS AS THE UPPER LOW
PULLS AWAY TO THE EAST. ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE
ACROSS THE MOUNTAINS. KCOS MAY SEE ANOTHER PASSING SHOWER IN THE
VCNTY OF THE TERMINAL SAT AFTN...WHILE KPUB AND KALS HAVE A
GREATER LIKELIHOOD OF STAYING DRY. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-063-
066-081.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT SATURDAY FOR COZ058-060-
061.
WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR COZ082.
&&
$$
UPDATE...ROSE
SHORT TERM...MOORE
LONG TERM...KT
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
627 PM MDT FRI APR 17 2015
.UPDATE...
ISSUED AT 613 PM MDT FRI APR 17 2015
LATEST HRRR IS MOVING THE PCPN OVER SERN CO INTO THE PALMER
DIVIDE SHORTLY THEN NORTHWEST INTO THE URBAN CORRIDOR. HAVE
INCREASED THE POPS THIS EVENING. PCPN WILL BE RAIN OR A RAIN/SNOW
MIX. DUE TO THE CONVECTIVE NATURE OF THIS SYSTEM...AREAS OVER THE
PALMER DIVIDE AND THE CHEYENNE RIDGE COULD PICK UP AN INCH OR TWO
OF SNOW. ANY SNOWFALL THAT DEVELOPS ELSEWHERE ALONG THE URBAN
CORRIDOR SHOULD BE AN INCH OR LESS. TORNADO WATCH REMAINS IN
EFFECT FOR MORGAN....WASHINGTON...LOGAN...SEDGWICK AND PHILLIPS
COUNTIES UNTIL MIDNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 124 PM MDT FRI APR 17 2015
UPPER LEVEL LOW CENTERED OVER SOUTH CENTRAL COLORADO WILL SLOWLY
SPIN NORTHEAST ACROSS THE STATE AND END UP OVER THE NORTHEAST CORNER
SATURDAY AFTERNOON. DRIER AIR HAS ROTATED NORTH ACROSS THE AREA THIS
AFTERNOON AND BROUGHT THE WIDESPREAD RAIN AND SNOW TO AN END.
CLEARING DUE TO THE DRIER AIR HAS ALLOWED SOME WARMING. HIRES MODELS
SHOWING SCATTERED CONVECTION FILLING IN DURING THE LATE AFTERNOON
AND EVENING. WILL KEEP SCATTERED TO LIKELY POPS IN THE FORECAST THIS
EVENING FOR THIS. ALREADY CANCELED THE ADVISORY WHERE THE SNOW ENDED
IN PARK COUNTY AND THE PALMER DIVIDE. MAY BE ABLE TO CANCEL THE
WINTER STORM WARNING AS WELL. WILL HOLD OFF FOR NOW AND SEE HOW MUCH
CONVECTION FORMS. OUTSIDE OF CONVECTION...ADDITIONAL SNOWFALL ONCE
THE DRY AIR MOVES THROUGH SHOULD BE LIGHT.
COOLED HIGH TEMPERATURES ARE FEW DEGREES FOR SATURDAY WITH COOL AIR
OVER US FROM THE UPPER LEVEL LOW. NORTHWEST FLOW BEHIND THE LOW
COMBINED WITH STEEP LAPSE WILL PRODUCE SNOW SHOWERS OVER THE
MOUNTAINS. INCREASED POPS FOR THIS. NEW SNOWFALL FOR THE MOUNTAINS
SATURDAY WILL GENERALLY BE LESS THAN 4 INCHES...THOUGH A FEW FAVORED
OROGRAPHIC AREAS COULD SEE A LITTLE MORE. FOR THE FRONT
RANGE...DOWNSLOPE FLOW WILL LIMIT PRECIPITATION CHANCES...THOUGH IT
SHOULD BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. THE BEST CHANCE WILL BE OVER THE PLAINS CLOSER TO THE
LOW AND AWAY FROM DOWNSLOPE. AIRMASS WILL BE WARM ENOUGH FOR RAIN
SATURDAY WITH SNOW CONFINED TO THE FOOTHILLS AND MOUNTAINS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 124 PM MDT FRI APR 17 2015
THE ACTIVE PATTERN CONTINUES THROUGH THE WEEKEND AND INTO EARLY
NEXT WEEK. SATURDAY NIGHT INTO SUNDAY THE UPPER LEVEL LOW CENTER
WILL MAKES ITS WAY EAST OVER THE CO AND KS BORDER. THIS WILL BRING
INCREASED NORTHERLY FLOW OVER NE COLORADO WITH A TROUGH OVER THE
WEST WILL HELP BRING A SURGE OF COOLER AIR THAT WILL SPREAD SNOW
SHOWERS OVER THE MOUNTAINS AND FOOTHILLS. THE TROUGH WILL PUSH
EAST HELPING TO DRY OUT THE PLAINS KEEPING THE REGION COOLER UNDER
MOSTLY CLOUDY SKIES. TEMPERATURES FOR SUNDAY WILL CONTINUE TO BE
BELOW SEASONAL NORMALS WITH HIGHS IN THE UPPER 40S TO LOWER 50S.
SUNDAY NIGHT INTO MONDAY STRONG NW WILL PREVAIL WITH A NW ORIENTED
JET MOVING INTO NE COLORADO. INCREASED MOISTURE IN THE MID LEVELS
WITH A SURFACE TROUGH WILL HELP TO KEEP SNOW IN THE MOUNTAINS AND
SCATTERED RAINSHOWERS OVER THE PLAINS THROUGH MONDAY NIGHT INTO
TUESDAY MORNING. WILL KEEP A SLIGHT CHANCE WITH THIS SYSTEM WITH A
CHANCE IN THE MOUNTAINS WITH DECENT ASCENT. TEMPERATURES FOR
MONDAY AND TUESDAY WILL SLOWLY INCREASE TO SEASONAL NORMALS BY
TUESDAY AFTERNOON AS THE UPPER LEVEL RIDING MOVES IN ALONG WITH
SURFACE HIGH PRESSURE. DOWNSLOPING WINDS OFF THE FOOTHILLS WILL
HELP TO WARM TEMPERATURES OVER THE PLAINS INTO WEDNESDAY WHERE
MODELS HAVE HIGH TEMPERATURES REACHING INTO THE UPPER 60S AND
LOWER 70S.
UPPER LEVEL FLOW TURNS SOUTHWESTERLY AHEAD OF THE NEXT DISTURBANCE
OVER SOUTHERN CA. THE MODELS DIVERGE AT THIS POINT WITH THE GFS
BRINGING PRECIPITATION BACK INTO THE MOUNTAINS BY WEDNESDAY
EVENING AND THE EC 24 HOURS BEHIND. WILL KEEP A SLIGHT CHANCE IN
THE GRIDS OR THIS PERIOD BUT WILL CONTINUE TO MONITOR MODEL
TRENDS.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 613 PM MDT FRI APR 17 2015
ANOTHER AREA OF RAINSHOWERS...POSSIBLY MIXING WITH SNOW SHOWERS...
APPROACHING FM THE SOUTH WILL MOVE NORTHWARD INTO THE URBAN
CORRIDOR FM 02Z-06Z. PREVAILING MVFR CONDITIONS WITH THE
POTENTIAL FOR IFR CIGS IF ANY HEAVY SHOWERS DEVELOP. PCPN WILL
PERSIST THROUGH 10Z WITH THE POTENTIAL FOR SOME PATCHY FOG
DEVELOPING TOWARDS 12Z. WINDS WILL BE OUT OF THE WEST/NORTHWEST
THEN MOVE NORTHERLY AS A MID LEVEL CYCLONE MOVES IN JUST EAST OF
THE AIRPORT....BACK TO WESTERLY SATURDAY MORNING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ033>036.
&&
$$
UPDATE...COOPER
SHORT TERM...MEIER
LONG TERM...BOWEN
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
424 PM MDT THU APR 16 2015
.UPDATE...
ISSUED AT 423 PM MDT THU APR 16 2015
UPDATED THE FORECAST TO CANCEL THE RED FLAG FOR THE SAN LUIS
VALLEY. SCATTERED SHOWERS ARE OVER THE VALLEY AND HUMIDITY IS
NO LONGER CRITICAL. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM MDT THU APR 16 2015
...MODERATE TO HEAVY SNOW POSSIBLE FOR THE MOUNTAINS TONIGHT AND
FRIDAY...
...CRITICAL FIRE WEATHER CONDITIONS POSSIBLE FOR THE FAR SOUTHEAST
PLAINS AGAIN ON FRIDAY THOUGH THIS IS DEPENDENT ON HOW MUCH RAIN
FALLS OVER THESE AREAS TONIGHT...
...MARGINAL POTENTIAL FOR SEVERE POSSIBLE FOR NORTHERN EL PASO AND
KIOWA COUNTIES ON FRIDAY...
STILL A HIGHLY DYNAMIC FORECAST AS MODELS HONE IN ON TRACK AND
STRENGTH OF THE CLOSED LOW CURRENTLY ACROSS THE 4 CORNERS REGION.
MODELS BOBBLE THE UPPER LOW SOUTHWARD A BIT THIS EVENING...THEN BACK
TO THE NORTHEAST ACROSS THE CO/NM BORDER TONIGHT AS ENERGY ROTATES
AROUND THE BASE OF THE UPPER LOW AND ACROSS CO. THEN IT MAKES
STEADIER PROGRESS TO THE NORTHEAST INTO EAST CENTRAL CO ON FRIDAY.
ALREADY SEEING ENHANCEMENT ACROSS THE SOUTHEAST MTS AND NRN NM AS
THE NEXT IMPULSE APPROACHES. HRRR SEEMS TO HAVE PICKED UP ON THIS
TREND FAIRLY WELL. WE SHOULD CONTINUE TO SEE SHOWERS FILL IN ACROSS
THE SOUTHEAST MOUNTAINS...AND I-25 CORRIDOR...WITH SNOW LEVELS
AROUND 6000-6500 FEET. SNOW LEVELS MAY ACTUALLY RISE A BIT FOR THE
LOWER EASTERN SLOPES AS STRONG WAA OCCURS OVERNIGHT...WHICH COULD
CAUSE A SWITCH BACK TO RAIN AT KCOS OVERNIGHT. HOWEVER...MTN AREAS
SHOULD CONTINUE TO SEE SNOW AND HAVE EXPANDED ADVISORIES ACROSS MUCH
OF THE MOUNTAIN AREAS. GIVEN THE CONVECTIVE POTENTIAL WITH THIS
EVENINGS ROUND...CONCERNED THAT PORTIONS OF TELLER COUNTY COULD HIT
WARNING CRITERIA...THOUGH DON`T THINK IT WILL BE WIDESPREAD ENOUGH
ACROSS THE ZONE TO WARRANT AN UPGRADE. CENTRAL LAKE COUNTY COULD BE
IN A SIMILAR BOAT...SO THESE AREAS WILL BE THE ONES TO WATCH
CLOSELY. MEANWHILE...MODELS SHOW DEFORMATION BAND SNOW SPREADING
WESTWARD INTO THE SOUTHWEST MOUNTAINS TONIGHT AND CONTINUING THROUGH
FRIDAY. HAVE OPTED TO EXPAND ADVISORIES INTO THE LA GARITAS WHERE
SNOW AMOUNTS ARE APPROACHING THE 6-12 INCH RANGE. STILL SOME
QUESTION OVER THE EASTERN SAN JUANS THOUGH...COULD SEE A COUPLE
INCHES FALL THERE TONIGHT...WITH ANOTHER 1-3 INCHES FALLING ON
FRIDAY AS THE UPPER LOW WRAPS DEFORMATION BAND BACK TO THE SOUTHWEST
ACROSS THE REGION. CONTEMPLATED AN ADVISORY FOR THIS REGION...BUT
AM COMING UP SHY OF THE 6-12 INCHES NEEDED FOR A WINTER WX
ADVISORY...THOUGH CERTAINLY SUBTLE CHANGES IN THE TRACK AND STRENGTH
OF THE LOW COULD RESULT IN HEAVIER AMOUNTS FOR THIS REGION.
STICKING TRUE TO THE GRIDS FOR NOW AND WILL LET LATER SHIFTS
REASSESS.
AS FOR SEVERE THUNDERSTORM POTENTIAL ACROSS THE PLAINS...APPEARS
TIMING OF THE INITIAL WAVE THIS AFTERNOON WAS TOO QUICK FOR THE LOW
LEVEL MOISTURE RETURN...AND NICE LINE OF THUNDERSTORMS HAS ALREADY
DEVELOPED AND PUSHED EASTWARD INTO KANSAS. HOWEVER AS SURFACE WINDS
HAVE VEERED MORE EASTERLY DUE TO FALLING SFC PRESSURES ACROSS NEW
MEXICO...40S AND LOWER 50 DEW POINTS HAVE PULLED WESTWARD INTO THE
FAR SOUTHEAST PLAINS. ACTIVITY INCREASING ACROSS NORTHERN NEW
MEXICO MAY STILL HAVE A CHANCE TO INTERACT WITH THIS MOISTURE TO
PRODUCE SOME ISOLATED SEVERE THUNDERSTORMS...WITH HAIL AND GUSTY
WINDS THE PRIMARY STORM THREATS. OVERNIGHT...LATEST HRRR HINTS AT
ANOTHER ROUND CLIPPING BY BACA COUNTY DURING THE 8Z TO 09Z
TIMEFRAME...AND EVEN SOME SPOTTY THUNDERSTORMS POSSIBLE AS FAR WEST
AS THE I-25 CORRIDOR. SO THOUGH MAIN THREAT FOR SEVERE
THUNDERSTORMS WILL BE THIS EVENING...CAN`T RULE OUT A LOW GRADE
SEVERE THREAT ACROSS THE FAR SOUTHEAST PLAINS EVEN DURING THE
OVERNIGHT HOURS...THOUGH THUNDERSTORMS WILL TEND TO BE MORE
ELEVATED. TOMORROW AS THE SURFACE LOW LIFTS INTO SOUTHEAST
CO...COULD SEE SOME ISOLATED THUNDERSTORMS EVEN IN THE MORNING...AND
LAPSE RATES WILL BE STEEP GIVEN THE MID LEVEL COOLING ASSOCIATED
WITH THE SURFACE LOW. NAM12 SHOWS UP TO 1000 J/KG OF CAPE ACROSS
NORTHERN PORTIONS OF THE SE PLAINS DURING THE MORNING...SO COULD
HAVE ANOTHER CHANCE FOR SEVERE THUNDERSTORMS ON FRIDAY. BY
AFTERNOON...DRY AIR SPREADS INTO THE SOUTHEAST PLAINS AS SURFACE LOW
LIFTS NORTHWARD. THIS PUTS THE AXIS OF BEST INSTABILITY ALONG THE
NORTHERN FRINGES OF THE SOUTHEAST PLAINS BY AFTERNOON...PRIMARILY
NORTHEAST EL PASO AND KIOWA COUNTIES. THESE AREAS ARE OUTLOOKED FOR
A MARGINAL SEVERE THREAT TOMORROW...AND THIS LOOKS ON TARGET. COULD
SEE THIS MARGINAL THREAT SLIPPING SOUTHWARD A BIT TO ACCOUNT FOR ANY
STRONG MORNING CONVECTION. BUT AS DRY AIR EXPANDS NORTHWARD...SO
DOES THE POTENTIAL FOR CRITICAL FIRE WEATHER PARAMETERS...ESPECIALLY
ACROSS LAS ANIMAS...BACA...BENT...PROWERS... AND OTERO COUNTIES.
THE MITIGATING FACTOR WILL BE THE POTENTIAL FOR RAINFALL TO WET
FUELS TONIGHT OVER THESE SAME ZONES. GIVEN THIS POTENTIAL...HAVE
NOT GONE OUT WITH A FIRE WEATHER WATCH...BUT IF PRECIPITATION
DOESN`T MATERIALIZE ACROSS A WIDESPREAD ENOUGH AREA ACROSS THESE
REGION...THEN LATER SHIFTS MAY NEED TO HOIST A RED FLAG WARNING. -KT
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 356 PM MDT THU APR 16 2015
FRIDAY NIGHT THROUGH SATURDAY...MODELS HAVE SHIFTED A BIT OVER THE
PST 24 HRS...BUT STILL REMAIN FAIRLY CONSISTENT WITH THE PLACEMENT
AND PATH OF THE UPPER LOW. FRIDAY NIGHT THE LOW PRESSURE SYSTEM IS
FORECAST TO BE CENTERED RIGHT OVER COLORADO...THEN OVER THE NEXT 24
HRS IT WILL WOBBLE A BIT BEFORE SLOWLY EXITING THE STATE VIA THE
EASTERN BORDER. THIS PATTERN WOULD IMPLY THAT THE MTS...ESPECIALLY
THE CONTDVD...WILL GET THE BRUNT OF SNOWFALL...MAINLY THROUGH FRIDAY
NIGHT. THEREFORE...ONGOING WINTER HIGHLIGHTS RUNNING THROUGH 12Z
SATURDAY LOOK REASONABLE. SNOW AMOUNTS WILL THEN TAPER OVER OVER THE
DAY SATURDAY AS TEMPS BEGIN TO WARM AND THE SYSTEM WEAKENS. ISOLATED
TO SCATTERED SHOWERS ARE FORECAST FOR THE REMAINDER OF THE LOWER
ELEVATIONS...AND TEMPS DO NOT LOOK PARTICULARLY COLD WITH MIN TEMPS
IN THE 30S TO AROUND 40 F FOR THE PLAINS...AND MAX TEMPS SATURDAY IN
THE MID 50S TO LOWER 60S.
SUNDAY AND MONDAY...THE UPPER SYSTEM WEAKENS AND EXITS TO THE EAST
LATE SATURDAY...WITH BRISK NW FLOW ALOFT THEN SETTLING IN ACROSS THE
STATE. A COUPLE OF UPPER SHORTWAVES ARE EXPECTED TO DROP DOWN ACROSS
THE STATE ON BOTH DAYS...KEEPING THE THREAT OF SHOWER ACTIVITY FOR
THE CWA IN PLACE. LOOK FOR SCATTERED SHOWERS OVER THE HIGHER
TERRAIN...AND ISOLATED SHOWERS FOR THE PLAINS...WITH MAX TEMPS BOTH
DAYS HOVERING IN THE 50S TO NEAR 60 F.
TUESDAY THROUGH THURSDAY...CONFIDENCE IS FAIRLY LOW FOR WHAT HAPPENS
BEYOND MONDAY...THOUGH LONG RANGE MODELS SEEM TO AGREE ON THE
QUESTION MARK. A TEMPORARY RIDGE BUILDS INTO THE DESERT SW STARTING
TUE...HELPING TO LOWERING PCPN CHANCES AS WELL AS BOOSTING MAX TEMPS
FOR THE PLAINS BACK INTO THE 70S. TWO SEPARATE UPPER CLOSED LOW
SYSTEMS APPROACH STARTING WED NIGHT...ONE OVER THE PAC NW AND THE
OTHER OVER S CA...BUT THIS PATTERN WILL MOST LIKELY GO THROUGH
MULTIPLE ADJUSTMENTS BEFORE THEN. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 356 PM MDT THU APR 16 2015
CURRENTLY...VFR TO MVFR CONDITIONS FOR THE THREE MAIN TAF SITES OF
KCOS...KPUB AND KALS AS WELL AS FOR MUCH OF THE LOWER ELEVATIONS.
FOR ELEVATIONS ABOVE ROUGHLY 7000 FT...IFR CONDITIONS PREVAILED
DUE TO EXTENSIVE LOWER CLOUD COVER AND ONGOING SNOW SHOWERS.
THE UPPER LOW WILL SLOWLY MOVE FROM THE SW QUAD TO THE CENTRAL
PORTIONS OF THE STATE OVER THE NEXT 24 HRS...BRINGING WAVES OF
RAIN/SNOW SHOWERS TO THE LOWER ELEVATIONS AND SNOW...HEAVY AT
TIMES...TO THE MTS. EXPECT MVFR CONDITIONS FOR KPUB AND KALS OVER
THE NEXT 24 HRS. KCOS IS EXPECTED TO DIP INTO IFR CONDITIONS THIS
EVENING...THEN BRIEFLY DROP DOWN INTO LIFR AFTER 11Z TOMORROW
MORN. CONDITIONS ACROSS THE HIGHER TERRAIN AND MT PASSES WILL
REMAIN IFR TO LIFR. MOORE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-062-
063-074-075.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT FRIDAY FOR COZ076>079.
WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ058-060-061-
072-073-080-082.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT FRIDAY NIGHT FOR
COZ066.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT FRIDAY NIGHT FOR
COZ081.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT FRIDAY FOR COZ084.
&&
$$
UPDATE...ROSE
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
357 PM MDT THU APR 16 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM MDT THU APR 16 2015
...MODERATE TO HEAVY SNOW POSSIBLE FOR THE MOUNTAINS TONIGHT AND
FRIDAY...
...CRITICAL FIRE WEATHER CONDITIONS POSSIBLE FOR THE FAR SOUTHEAST
PLAINS AGAIN ON FRIDAY THOUGH THIS IS DEPENDENT ON HOW MUCH RAIN
FALLS OVER THESE AREAS TONIGHT...
...MARGINAL POTENTIAL FOR SEVERE POSSIBLE FOR NORTHERN EL PASO AND
KIOWA COUNTIES ON FRIDAY...
STILL A HIGHLY DYNAMIC FORECAST AS MODELS HONE IN ON TRACK AND
STRENGTH OF THE CLOSED LOW CURRENTLY ACROSS THE 4 CORNERS REGION.
MODELS BOBBLE THE UPPER LOW SOUTHWARD A BIT THIS EVENING...THEN BACK
TO THE NORTHEAST ACROSS THE CO/NM BORDER TONIGHT AS ENERGY ROTATES
AROUND THE BASE OF THE UPPER LOW AND ACROSS CO. THEN IT MAKES
STEADIER PROGRESS TO THE NORTHEAST INTO EAST CENTRAL CO ON FRIDAY.
ALREADY SEEING ENHANCEMENT ACROSS THE SOUTHEAST MTS AND NRN NM AS
THE NEXT IMPULSE APPROACHES. HRRR SEEMS TO HAVE PICKED UP ON THIS
TREND FAIRLY WELL. WE SHOULD CONTINUE TO SEE SHOWERS FILL IN ACROSS
THE SOUTHEAST MOUNTAINS...AND I-25 CORRIDOR...WITH SNOW LEVELS
AROUND 6000-6500 FEET. SNOW LEVELS MAY ACTUALLY RISE A BIT FOR THE
LOWER EASTERN SLOPES AS STRONG WAA OCCURS OVERNIGHT...WHICH COULD
CAUSE A SWITCH BACK TO RAIN AT KCOS OVERNIGHT. HOWEVER...MTN AREAS
SHOULD CONTINUE TO SEE SNOW AND HAVE EXPANDED ADVISORIES ACROSS MUCH
OF THE MOUNTAIN AREAS. GIVEN THE CONVECTIVE POTENTIAL WITH THIS
EVENINGS ROUND...CONCERNED THAT PORTIONS OF TELLER COUNTY COULD HIT
WARNING CRITERIA...THOUGH DON`T THINK IT WILL BE WIDESPREAD ENOUGH
ACROSS THE ZONE TO WARRANT AN UPGRADE. CENTRAL LAKE COUNTY COULD BE
IN A SIMILAR BOAT...SO THESE AREAS WILL BE THE ONES TO WATCH
CLOSELY. MEANWHILE...MODELS SHOW DEFORMATION BAND SNOW SPREADING
WESTWARD INTO THE SOUTHWEST MOUNTAINS TONIGHT AND CONTINUING THROUGH
FRIDAY. HAVE OPTED TO EXPAND ADVISORIES INTO THE LA GARITAS WHERE
SNOW AMOUNTS ARE APPROACHING THE 6-12 INCH RANGE. STILL SOME
QUESTION OVER THE EASTERN SAN JUANS THOUGH...COULD SEE A COUPLE
INCHES FALL THERE TONIGHT...WITH ANOTHER 1-3 INCHES FALLING ON
FRIDAY AS THE UPPER LOW WRAPS DEFORMATION BAND BACK TO THE SOUTHWEST
ACROSS THE REGION. CONTEMPLATED AN ADVISORY FOR THIS REGION...BUT
AM COMING UP SHY OF THE 6-12 INCHES NEEDED FOR A WINTER WX
ADVISORY...THOUGH CERTAINLY SUBTLE CHANGES IN THE TRACK AND STRENGTH
OF THE LOW COULD RESULT IN HEAVIER AMOUNTS FOR THIS REGION.
STICKING TRUE TO THE GRIDS FOR NOW AND WILL LET LATER SHIFTS
REASSESS.
AS FOR SEVERE THUNDERSTORM POTENTIAL ACROSS THE PLAINS...APPEARS
TIMING OF THE INITIAL WAVE THIS AFTERNOON WAS TOO QUICK FOR THE LOW
LEVEL MOISTURE RETURN...AND NICE LINE OF THUNDERSTORMS HAS ALREADY
DEVELOPED AND PUSHED EASTWARD INTO KANSAS. HOWEVER AS SURFACE WINDS
HAVE VEERED MORE EASTERLY DUE TO FALLING SFC PRESSURES ACROSS NEW
MEXICO...40S AND LOWER 50 DEW POINTS HAVE PULLED WESTWARD INTO THE
FAR SOUTHEAST PLAINS. ACTIVITY INCREASING ACROSS NORTHERN NEW
MEXICO MAY STILL HAVE A CHANCE TO INTERACT WITH THIS MOISTURE TO
PRODUCE SOME ISOLATED SEVERE THUNDERSTORMS...WITH HAIL AND GUSTY
WINDS THE PRIMARY STORM THREATS. OVERNIGHT...LATEST HRRR HINTS AT
ANOTHER ROUND CLIPPING BY BACA COUNTY DURING THE 8Z TO 09Z
TIMEFRAME...AND EVEN SOME SPOTTY THUNDERSTORMS POSSIBLE AS FAR WEST
AS THE I-25 CORRIDOR. SO THOUGH MAIN THREAT FOR SEVERE
THUNDERSTORMS WILL BE THIS EVENING...CAN`T RULE OUT A LOW GRADE
SEVERE THREAT ACROSS THE FAR SOUTHEAST PLAINS EVEN DURING THE
OVERNIGHT HOURS...THOUGH THUNDERSTORMS WILL TEND TO BE MORE
ELEVATED. TOMORROW AS THE SURFACE LOW LIFTS INTO SOUTHEAST
CO...COULD SEE SOME ISOLATED THUNDERSTORMS EVEN IN THE MORNING...AND
LAPSE RATES WILL BE STEEP GIVEN THE MID LEVEL COOLING ASSOCIATED
WITH THE SURFACE LOW. NAM12 SHOWS UP TO 1000 J/KG OF CAPE ACROSS
NORTHERN PORTIONS OF THE SE PLAINS DURING THE MORNING...SO COULD
HAVE ANOTHER CHANCE FOR SEVERE THUNDERSTORMS ON FRIDAY. BY
AFTERNOON...DRY AIR SPREADS INTO THE SOUTHEAST PLAINS AS SURFACE LOW
LIFTS NORTHWARD. THIS PUTS THE AXIS OF BEST INSTABILITY ALONG THE
NORTHERN FRINGES OF THE SOUTHEAST PLAINS BY AFTERNOON...PRIMARILY
NORTHEAST EL PASO AND KIOWA COUNTIES. THESE AREAS ARE OUTLOOKED FOR
A MARGINAL SEVERE THREAT TOMORROW...AND THIS LOOKS ON TARGET. COULD
SEE THIS MARGINAL THREAT SLIPPING SOUTHWARD A BIT TO ACCOUNT FOR ANY
STRONG MORNING CONVECTION. BUT AS DRY AIR EXPANDS NORTHWARD...SO
DOES THE POTENTIAL FOR CRITICAL FIRE WEATHER PARAMETERS...ESPECIALLY
ACROSS LAS ANIMAS...BACA...BENT...PROWERS... AND OTERO COUNTIES.
THE MITIGATING FACTOR WILL BE THE POTENTIAL FOR RAINFALL TO WET
FUELS TONIGHT OVER THESE SAME ZONES. GIVEN THIS POTENTIAL...HAVE
NOT GONE OUT WITH A FIRE WEATHER WATCH...BUT IF PRECIPITATION
DOESN`T MATERIALIZE ACROSS A WIDESPREAD ENOUGH AREA ACROSS THESE
REGION...THEN LATER SHIFTS MAY NEED TO HOIST A RED FLAG WARNING. -KT
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 356 PM MDT THU APR 16 2015
FRIDAY NIGHT THROUGH SATURDAY...MODELS HAVE SHIFTED A BIT OVER THE
PST 24 HRS...BUT STILL REMAIN FAIRLY CONSISTENT WITH THE PLACEMENT
AND PATH OF THE UPPER LOW. FRIDAY NIGHT THE LOW PRESSURE SYSTEM IS
FORECAST TO BE CENTERED RIGHT OVER COLORADO...THEN OVER THE NEXT 24
HRS IT WILL WOBBLE A BIT BEFORE SLOWLY EXITING THE STATE VIA THE
EASTERN BORDER. THIS PATTERN WOULD IMPLY THAT THE MTS...ESPECIALLY
THE CONTDVD...WILL GET THE BRUNT OF SNOWFALL...MAINLY THROUGH FRIDAY
NIGHT. THEREFORE...ONGOING WINTER HIGHLIGHTS RUNNING THROUGH 12Z
SATURDAY LOOK REASONABLE. SNOW AMOUNTS WILL THEN TAPER OVER OVER THE
DAY SATURDAY AS TEMPS BEGIN TO WARM AND THE SYSTEM WEAKENS. ISOLATED
TO SCATTERED SHOWERS ARE FORECAST FOR THE REMAINDER OF THE LOWER
ELEVATIONS...AND TEMPS DO NOT LOOK PARTICULARLY COLD WITH MIN TEMPS
IN THE 30S TO AROUND 40 F FOR THE PLAINS...AND MAX TEMPS SATURDAY IN
THE MID 50S TO LOWER 60S.
SUNDAY AND MONDAY...THE UPPER SYSTEM WEAKENS AND EXITS TO THE EAST
LATE SATURDAY...WITH BRISK NW FLOW ALOFT THEN SETTLING IN ACROSS THE
STATE. A COUPLE OF UPPER SHORTWAVES ARE EXPECTED TO DROP DOWN ACROSS
THE STATE ON BOTH DAYS...KEEPING THE THREAT OF SHOWER ACTIVITY FOR
THE CWA IN PLACE. LOOK FOR SCATTERED SHOWERS OVER THE HIGHER
TERRAIN...AND ISOLATED SHOWERS FOR THE PLAINS...WITH MAX TEMPS BOTH
DAYS HOVERING IN THE 50S TO NEAR 60 F.
TUESDAY THROUGH THURSDAY...CONFIDENCE IS FAIRLY LOW FOR WHAT HAPPENS
BEYOND MONDAY...THOUGH LONG RANGE MODELS SEEM TO AGREE ON THE
QUESTION MARK. A TEMPORARY RIDGE BUILDS INTO THE DESERT SW STARTING
TUE...HELPING TO LOWERING PCPN CHANCES AS WELL AS BOOSTING MAX TEMPS
FOR THE PLAINS BACK INTO THE 70S. TWO SEPARATE UPPER CLOSED LOW
SYSTEMS APPROACH STARTING WED NIGHT...ONE OVER THE PAC NW AND THE
OTHER OVER S CA...BUT THIS PATTERN WILL MOST LIKELY GO THROUGH
MULTIPLE ADJUSTMENTS BEFORE THEN. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 356 PM MDT THU APR 16 2015
CURRENTLY...VFR TO MVFR CONDITIONS FOR THE THREE MAIN TAF SITES OF
KCOS...KPUB AND KALS AS WELL AS FOR MUCH OF THE LOWER ELEVATIONS.
FOR ELEVATIONS ABOVE ROUGHLY 7000 FT...IFR CONDITIONS PREVAILED
DUE TO EXTENSIVE LOWER CLOUD COVER AND ONGOING SNOW SHOWERS.
THE UPPER LOW WILL SLOWLY MOVE FROM THE SW QUAD TO THE CENTRAL
PORTIONS OF THE STATE OVER THE NEXT 24 HRS...BRINGING WAVES OF
RAIN/SNOW SHOWERS TO THE LOWER ELEVATIONS AND SNOW...HEAVY AT
TIMES...TO THE MTS. EXPECT MVFR CONDITIONS FOR KPUB AND KALS OVER
THE NEXT 24 HRS. KCOS IS EXPECTED TO DIP INTO IFR CONDITIONS THIS
EVENING...THEN BRIEFLY DROP DOWN INTO LIFR AFTER 11Z TOMORROW
MORN. CONDITIONS ACROSS THE HIGHER TERRAIN AND MT PASSES WILL
REMAIN IFR TO LIFR. MOORE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-062-
063.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT FRIDAY FOR COZ076>079.
WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ058-060-061-
072-073-080-082.
RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ224.
WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ074-075.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT MDT
FRIDAY NIGHT FOR COZ066.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT FRIDAY NIGHT FOR
COZ081.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MDT
FRIDAY FOR COZ084.
&&
$$
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
308 PM MDT THU APR 16 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 257 PM MDT THU APR 16 2015
WATER VAPOR SATELLITE IMAGERY SHOWING THE UPPER LEVEL LOW
CENTERED OVER THE FOUR CORNERS AT THIS TIME WITH A SHORT WAVE
ROTATING AROUND IT OVER NORTH CENTRAL NEW MEXICO. THIS WAVE WILL
ROTATE NORTH OVER EASTERN COLORADO TONIGHT BRINGING WIDESPREAD
RAIN AND SNOW TO THE AREA.
IN ADDITION TO THE WAVE PASSING ACROSS THE AREA...UPSLOPE WINDS WILL
REMAIN STRONG AT 20 TO 40 KNOTS ALONG THE FRONT RANGE. EXPECT
MODERATE TO HEAVY SNOW THROUGH THE NIGHT WITH SNOWFALL RATES 1 TO 2
INCHES PER HOUR AT TIMES IN THE FOOTHILLS AND MOUNTAINS. LAPSE RATES
ARE ALSO STEEP...SO A FEW THUNDERSTORMS WILL BE POSSIBLE TONIGHT.
WILL MENTION A SLIGHT CHANCE IN THE FORECAST FOR THE FRONT RANGE AND
EASTERN PLAINS TONIGHT AND FRIDAY. MODELS GENERALLY SHOWING 1 TO 2
INCHES OF PRECIPITATION THROUGH FRIDAY MORNING WITH THIS SYSTEM...A
LITTLE MORE OVER LARIMER COUNTY. SO 1 TO 3 FEET LOOKS ON TRACK FOR
SNOWFALL AMOUNTS IN THE FOOTHILLS AND FRONT RANGE MOUNTAINS.
EXPECT A RAIN/SNOW MIX THIS EVENING BETWEEN 5000 TO 6000 FEET WITH
OCCASIONAL HEAVY SNOW UNDER THE STRONGEST SHOWERS. EASTERLY WINDS
AROUND THE LOW WILL CONTINUE TO PUMP MOISTURE INTO THE AREA ALONG
WITH WARMER AIR. THIS IS EXPECTED TO CHANGE SNOW TO RAIN ACROSS THE
DENVER AREA OVERNIGHT. BY FRIDAY MORNING...EXPECT RAIN FOR MOST
PLACES UNDER 6000 FEET. MAY SEE UP TO 6 INCHES OF SLUSHY SNOW PRIOR
TO CHANGING TO RAIN IN THE DENVER AREA OVERNIGHT...POSSIBLY A LITTLE
MORE NEAR THE FOOTHILLS AND PALMER DIVIDE. WILL ISSUE AN ADVISORY
FOR PARK COUNTY AND PALMER DIVIDE WHERE AN ADDITIONAL 4 TO 8 INCHES
WILL BE POSSIBLE.
ON FRIDAY...THE UPPER LEVEL LOW WILL LIFT INTO COLORADO. AT THE
SURFACE...A LOW WILL MOVE EAST ACROSS EASTERN COLORADO. TO THE NORTH
AND EAST OF THE SURFACE LOW...SURFACE BASED CAPES CLIMB TO AROUND
2000 J/KG BASED ON THE 18Z NAM. WITH STRONG SHEAR IN PLACE...THIS
WILL BE ENOUGH INSTABILITY FOR A CHANCE OF SEVERE
THUNDERSTORMS...MAIN THREATS WILL BE LARGE HAIL UP TO GOLF BALL SIZE
AND TORNADOS. RIGHT NOW APPEARS THE BEST CHANCE WILL BE FROM GREELEY
TO LIMON AND EASTWARD...THOUGH THIS WILL DEPEND ON WHERE THE LOW
TRACKS. FOR THE FOOTHILLS AND MOUNTAINS...STILL LOOKS LIKE IT WILL
STAY COLD ENOUGH FOR SNOW THROUGH THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 257 PM MDT THU APR 16 2015
THE FIRST PART OF THE LONG TERM FORECAST HINGES OF THE LOCATION AND
MOVEMENT OF THE 500 MB UPPER LEVEL LOW PRESSURE SYSTEM. THE MODELS
ARE IN PRETTY GOOD AGREEMENT...HOWEVER JUST A SLIGHT DEVIATION IN
THE UPPER LOW TRACK WOULD AFFECT PRECIPITATION AND SNOWFALL AMOUNTS
ACROSS NORTH CENTRAL AND NORTHEASTERN COLORADO. THE ECMWF HAS BEEN
VERY CONSISTENT AND HAS THE 500 MB LOW CENTERED JUST WEST OF
COLORADO SPRINGS AT 00Z SATURDAY. THE GFS AND NAM MODELS HAVE THE
CENTER NEAR CANON CITY WHICH IS APPROXIMATELY 75 SOUTH OF THE
PREVIOUS TWO RUNS. THESE MODELS THEN TRACK THE LOW TO NEAR DENVER BY
12Z SATURDAY MORNING. AS THE LOW MOVES NORTH DENVER SHOULD SEE A
DECREASE IN PRECIPITATION...HOWEVER THE MOUNTAINS AND FOOTHILLS NEAR
THE WYOMING BORDER COULD STILL BE UNDER THE GUN AS WRAP AROUND
PRECIP WRAPS INTO THE REGION FROM THE NORTH. THE 15Z RUC JUST CAME
IN AND SHOWS THE UPPER LOW TAKING A MORE SOUTHERLY TRACK ACROSS
SOUTHERN COLORADO. THIS TRACK COULD PROLONG THE PRECIP EVENT BUT FOR
NOW WILL GO WITH THE CONSENSUS OF THE GFS...ECMWF AND NAM.
PRECIPITATION CHANCES DECREASE SATURDAY NIGHT INTO SUNDAY AS THE
UPPER LOW WEAKENS AND MOVES INTO THE CENTRAL PLAINS STATES AND A
NORTHWEST FLOW ALOFT DEVELOPS OVER THE STATE.
UNSETTLED WEATHER WILL CONTINUE ACROSS NORTH CENTRAL AND
NORTHEASTERN COLORADO THROUGH MONDAY AS RESIDUAL MOISTURE COMBINES
WITH INSTABILITY DUE TO DAYTIME HEATING. A WEAK SURGE IN THE
NORTHWEST FLOW COULD ENHANCE PRECIPITATION CHANCES. WARMER AND
DRIER WEATHER WILL RETURN TO THE REGION ON TUESDAY AS UPPER LEVEL
HIGH PRESSURE BUILDS OVER THE ROCKY MOUNTAIN REGION.
&&
.AVIATION...(FOR THE TAFS THROUGH 00Z FRIDAY LATE AFTERNOON)
ISSUED AT 257 PM MDT THU APR 16 2015
RAIN AND SNOW WILL CONTINUE THROUGH THE EVENING AND EVENTUALLY TURN
TO RAIN BY FRIDAY MORNING. VISIBILITY WILL FALL TO A QUARTER MILE AT
TIMES IN THE HEAVIER SNOW. CEILINGS WILL BE UNDER 1000 FEET AND ONLY
OCCASIONAL BE HIGHER THAN THAT. NORTHERLY WINDS WILL PREVAIL AT
SPEEDS LESS THAN 20 KNOTS. SNOW ACCUMULATION AT KDEN IS EXPECTED TO
STAY BELOW 3 INCHES...WITH UP TO 6 INCHES POSSIBLE AT KAPA AND KBJC.
IN ADDITION TO THE RAIN/SNOW...ISOLATED THUNDERSTORMS ARE EXPECTED
TO FORM...MAINLY THIS EVENING THEN AGAIN FRIDAY AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MDT
FRIDAY FOR COZ037-041.
WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR COZ033>036.
&&
$$
SHORT TERM...MEIER
LONG TERM...JK
AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1137 AM MDT THU APR 16 2015
.UPDATE...
ISSUED AT 1134 AM MDT THU APR 16 2015
RATHER NARROW BAND OF HEAVIER SNOW STILL PERSISTED ACROSS A
PORTION OF WEST-CENTRAL CO LATE THIS MORNING AS THE FIRST IN
SERIES OF DISTURBANCES ROTATED AROUND A FOUR CORNERS LOW AND NORTH
INTO CO. SNOW HAS TAKEN A BREAK AT MONTROSE BUT CONTINUED AT GRAND
JCT AT 11 AM. SOME AREAS IN THE GRAND VALLEY HAVE SEEN LOCALLY UP
TO AN INCH OR TWO ON GRASSY AREAS PER PUBLIC REPORTS...BUT EXPECT
THIS TO MELT THIS AFTERNOON AS THIS BAND MOVES OUT AND TEMPS WARM.
HOWEVER...DID UPDATE TO LOWER THE HIGH TEMPS TODAY ACROSS THE
CENTRAL FORECAST AREA DUE TO THIS MORNING`S CLOUDS AND PRECIP
HAMPERING THE DIURNAL WARM-UP.
16Z RAP SHOWS ANOTHER WAVE ROTATING NORTH TROUGH CENTRAL CO TONIGHT.
EXPECT THIS TO BRING ANOTHER ROUND OF HEAVIER PRECIP FOR AT LEAST
THE CENTRAL MTNS AND NRN MTNS AS EASTERLY FLOW ALSO BRINGS MORE
MOISTURE ACROSS THE DIVIDE. THE 12Z NAM AND GFS SHOW THE MAIN UPPER
LOW OVER SW CO/NW NM FRI MORNING.
UPDATE ISSUED AT 936 AM MDT THU APR 16 2015
GRAND JCT RADAR INDICATED AN AREA OF ENHANCED PRECIPITATION ACROSS
WEST-CENTRAL CO THIS MORNING. MUCH OF THIS PRECIP WAS SNOW PER
PUBLIC REPORTS AND WEBCAM IMAGES. NOT EXPECTING ANY LONG-LASTING
ACCUMULATIONS IN THESE VALLEYS THOUGH PERIODS OF HEAVIER SNOW MAY
TEMPORARILY WHITEN GRASSY SURFACES. HI-RESOLUTION HRRR AND RAP
MODELS SHOW THIS AREA DECREASING...OR AT LEAST SLIDING NORTH AND
NORTHEAST...BY LATE MORNING. EXPECT TO SEE COVERAGE INCREASE ACROSS
ALL OF THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA THIS
AFTERNOON AS CONVECTIVE INSTABILITY KICKS IN EVEN MORE.
LET THE FREEZE WARNING EXPIRE AT 9 AM THIS MORNING. SOME AREAS WHERE
SNOW IS OCCURRING MAY STILL BE IN THE UPPER 20S FOR A BIT LONGER
THOUGH...LIKE DELTA/MONTROSE/PAONIA AREAS. FREEZE WATCH REMAINS
FOR THE CORTEZ-YELLOWJACKET AREA EARLY FRI MORNING.
UPDATE ISSUED AT 613 AM MDT THU APR 16 2015
SOCIAL MEDIA REPORTS OF HOWLING WINDS IN THE STEAMBOAT SPRINGS
AREA HAVE BEEN RECEIVED EARLY THIS MORNING...PEAK GUSTS ON SENSORS
IN THE AREA SHOWING 25-35 MPH SO FAR THIS MORNING. PATTERN IS
SETTING UP FOR A POTENTIAL DOWNSLOPE WIND EVENT IN THIS REGION
LATER THIS AFTERNOON AND TONIGHT. STRONG H7 FLOW AROUND NORTH
SIDE OF THE LOW EXPECTED TO EXCEED 50 KTS AND WE HAVE SEEN THIS
TYPE OF FLOW IN THE PAST GENERATE STRONG DOWNSLOPE WINDS IN THE
STEAMBOAT AND ZIRKEL WILDERNESS AREAS. TRACK OF THE UPPER LOW WILL
PLAY CRITICAL ROLE AND MODELS STILL A BIT OUT OF PHASE IN EXACT
PATH...SO WILL CONTINUE TO MONITOR AND ADVISE LATER SHIFTS OF THIS
POTENTIAL. IN THE MEANTIME...BOOSTED SPEEDS UP A FEW CATEGORIES
FOR TODAY WITH GUSTS UP TO 50 MPH FOR THE HILLS AND GUST TO UP TO 45
FOR THE VALLEYS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 416 AM MDT THU APR 16 2015
SPRING IN THE CENTRAL ROCKIES IS REARING ITS UGLY HEAD AS
TEMPERATURES THIS MORNING HAVE DIPPED BELOW FREEZING IN MANY
LOCATIONS WHICH HAVE ALREADY BEGUN THEIR GROWING SEASONS...WHILE
OTHERS (THE EASTERN UINTAS) HAVE ALREADY SEEN A DECENT AMOUNT OF
ACCUMULATING SNOW. A LARGE CLOSED LOW IS CURRENTLY OVER SOUTHEAST
UTAH AND WILL SLOWLY PROGRESS SOUTH TO THE FOUR CORNERS LATER THIS
MORNING. MODELS ARE IN GOOD AGREEMENT THAT SIGNIFICANT SNOW IS
GOING TO FALL AT ELEVATIONS MAINLY HIGHER THAN 9000 FT STARTING
THIS AFTERNOON ACROSS THE WEST CENTRAL COLORADO MOUNTAINS AND WILL
CONTINUE TO FALL OVER THE EASTERN UINTAS. THOUGH WINDS WILL NOT BE
FAVORABLE FOR CONSTANT SNOWFALL DURING THE ENTIRE TIME PERIOD OF
THE WINTER HAZARDS...WHEN THE DIRECTION IS RIGHT COMBINED WITH
LIFTING DUE TO THE PASSING CLOSED LOW...HEAVY WET SNOW WILL PILE
UP QUICKLY AT THESE HIGHER LOCATIONS. HAVE KEPT A CLOSE EYE ON THE
MOISTURE FIELDS OVER THE LAST FEW DAYS AND HAVE SEEN THE FORECAST
MODELS INCREASE MOISTURE FROM THE SOUTH AND NOW INCREASE MOISTURE
ACROSS WESTERN CO AND EASTERN UT AS IT WRAPS AROUND THE SLOWLY
PROGRESSING CLOSED LOW. THE SLOW MOVEMENT AND DYNAMICS OF THE LOW
SHOULD BE EFFECTIVE IN OVERCOMING THE MOUNTAIN SHADOW EFFECT. SPEC
HUMIDITY VALUES ARE NOW BEING PROGGED TO REACH AND EXCEED 4 G/KG
WHICH IS RATHER SIGNIFICANT WITH SUCH A COLD SYSTEM IN APRIL. SNOW
LEVEL IS DEFINITELY A CHALLENGE AND AM EXPECTING NORTHERN COLORADO
VALLEYS TO SEE MAINLY RAIN AND A RAIN/SNOW MIX WITH LITTLE
ACCUMULATION. AN UPTICK IN ACTIVITY IS EXPECTED THIS AFTERNOON AND
EVENING...BUT ALL FORECAST MODELS REALLY PICK UP COVERAGE IN
ACTIVITY FRIDAY AFTERNOON. CONDITIONS NORTH OF I-70 TODAY WILL BE
BREEZY AND WET MUCH OF TODAY. ELSEWHERE WILL RECEIVE SCATTERED
SHOWERS WITH THE EXCEPTION OF THE CENTRAL MOUNTAINS WHICH WILL SEE
DETERIORATING CONDITIONS TODAY.
ADDED NORTHERN SAN JUANS TO A WINTER STORM WATCH STARTING TONIGHT
AS WE ANTICIPATE FLOW CHANGING TO WEST NORTHWESTERLY. STRONG
NORTHERLY FLOW FRIDAY EVENING WILL ALSO BE FAVORABLE FOR THIS AREA
TO RECEIVE HEAVY SNOW IF THE LOW STAYS ON TRACK. CONFIDENCE IS
MODERATE ON CURRENT SOLUTIONS EVEN A COUPLE DAYS OUT DUE TO THE
LOW TRACKING SO SLOWLY ACROSS THE REGION.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 416 AM MDT THU APR 16 2015
MEANDERING LOW WILL CONTINUE TO WREAK HAVOC ON THE FORECAST AS WE
START OFF THIS EXTENDED PERIOD. DEEP NORTHERLY FLOW ON THE BACK
SIDE OF THE...EXPECTED TO BE EXITING LOW PRESSURE SYSTEM...MAY
KEEP LOCALLY HEAVY SNOW FALLING ACROSS THE NORTHWEST SAN JUAN
MOUNTAINS AND OTHER FAVORED NORTH FACING SLOPES IN WESTERN
COLORADO. THIS SYSTEM LOOKS TO LINGER OVER THE AREA UNTIL MIDDAY
SATURDAY...BEFORE A KICKING WAVE DROPS INTO MONTANA LATE SATURDAY
AFTERNOON AND EVENING. THIS SYSTEM SHOULD KICK THE LOW OUT INTO
THE PLAINS WITH SOMEWHAT MOIST NW FLOW HOLDING IN PLACE THROUGH
THE REMAINDER OF THE WEEKEND. SO EXPECT UNSETTLED CONDITIONS TO
CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS WITH ADDITIONAL
LATE SEASON SNOWFALL ANTICIPATED...ESPECIALLY ABOVE THE 9K LEVEL.
SLIGHT INCREASE IN HEIGHTS EXPECTED AS WE MOVE INTO THE NEW WORK
WEEK...WHICH WILL MODIFY TEMPS UP A BIT. HOWEVER...ENOUGH PACIFIC
MOISTURE STREAMING INTO THE REGION TO KEEP ISOLATED TO SCATTERED
POPS ROLLING THROUGHOUT THE PERIOD...GENERALLY FOCUSED ON THE
HIGHER TERRAIN. ANOTHER STRONG CLOSED LOW BEING ADVERTISED BY BOTH
THE GFS AND ECMWF LATE NEXT WEEK PROMISES TO BRING MORE WIDESPREAD
PRECIPITATION TO THE REGION AS WE CLOSE THE WEEK OUT. EXPECT
TEMPS TO BE RUNNING NEAR TO SLIGHTLY BELOW NORMAL THROUGH THIS
PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1054 AM MDT THU APR 16 2015
A STRONG LOW PRESSURE SYSTEM NEAR THE FOUR CORNERS AREA THIS
AFTERNOON AND THIS EVENING...WILL MEANDER SLOWLY INTO SOUTH-
CENTRAL COLORADO BY MIDDAY FRIDAY. EXPECT WIDESPREAD SHOWERS
ACROSS THE REGION BY THIS AFTERNOON...WITH LOCALLY HEAVY SNOW
EXPECTED OVER THE MOUNTAINS THROUGH SATURDAY. SNOW WILL SWITCH
OVER TO RAIN IN THE LOWER VALLEYS AT TIMES THIS AFTERNOON. CIGS
AND VSBY WILL DROP IN SHOWERS WITH AREAS OF MVFR AND IFR CONDS.
THESE POOR CONDITIONS WILL BECOME MORE WIDESPREAD LATER TONIGHT.
MOUNTAINS WILL BECOME OBSCURED... ESPECIALLY NEAR SHOWERS. GUSTY
EASTERLY WINDS CAN BE EXPECTED ACROSS WESTERN COLORADO AND EASTERN
UTAH THROUGH FRIDAY MORNING.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ004-009-
013.
WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR COZ010-012.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING
FOR COZ018.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ021.
UT...WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR UTZ023.
&&
$$
UPDATE...JAD
SHORT TERM...JAM
LONG TERM...JDC
AVIATION...EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1054 AM MDT THU APR 16 2015
.UPDATE...
ISSUED AT 936 AM MDT THU APR 16 2015
GRAND JCT RADAR INDICATED AN AREA OF ENHANCED PRECIPITATION ACROSS
WEST-CENTRAL CO THIS MORNING. MUCH OF THIS PRECIP WAS SNOW PER
PUBLIC REPORTS AND WEBCAM IMAGES. NOT EXPECTING ANY LONG-LASTING
ACCUMULATIONS IN THESE VALLEYS THOUGH PERIODS OF HEAVIER SNOW MAY
TEMPORARILY WHITEN GRASSY SURFACES. HI-RESOLUTION HRRR AND RAP
MODELS SHOW THIS AREA DECREASING...OR AT LEAST SLIDING NORTH AND
NORTHEAST...BY LATE MORNING. EXPECT TO SEE COVERAGE INCREASE ACROSS
ALL OF THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA THIS
AFTERNOON AS CONVECTIVE INSTABILITY KICKS IN EVEN MORE.
LET THE FREEZE WARNING EXPIRE AT 9 AM THIS MORNING. SOME AREAS WHERE
SNOW IS OCCURRING MAY STILL BE IN THE UPPER 20S FOR A BIT LONGER
THOUGH...LIKE DELTA/MONTROSE/PAONIA AREAS. FREEZE WATCH REMAINS
FOR THE CORTEZ-YELLOWJACKET AREA EARLY FRI MORNING.
UPDATE ISSUED AT 613 AM MDT THU APR 16 2015
SOCIAL MEDIA REPORTS OF HOWLING WINDS IN THE STEAMBOAT SPRINGS
AREA HAVE BEEN RECEIVED EARLY THIS MORNING...PEAK GUSTS ON SENSORS
IN THE AREA SHOWING 25-35 MPH SO FAR THIS MORNING. PATTERN IS
SETTING UP FOR A POTENTIAL DOWNSLOPE WIND EVENT IN THIS REGION
LATER THIS AFTERNOON AND TONIGHT. STRONG H7 FLOW AROUND NORTH
SIDE OF THE LOW EXPECTED TO EXCEED 50 KTS AND WE HAVE SEEN THIS
TYPE OF FLOW IN THE PAST GENERATE STRONG DOWNSLOPE WINDS IN THE
STEAMBOAT AND ZIRKEL WILDERNESS AREAS. TRACK OF THE UPPER LOW WILL
PLAY CRITICAL ROLE AND MODELS STILL A BIT OUT OF PHASE IN EXACT
PATH...SO WILL CONTINUE TO MONITOR AND ADVISE LATER SHIFTS OF THIS
POTENTIAL. IN THE MEANTIME...BOOSTED SPEEDS UP A FEW CATEGORIES
FOR TODAY WITH GUSTS UP TO 50 MPH FOR THE HILLS AND GUST TO UP TO 45
FOR THE VALLEYS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 416 AM MDT THU APR 16 2015
SPRING IN THE CENTRAL ROCKIES IS REARING ITS UGLY HEAD AS
TEMPERATURES THIS MORNING HAVE DIPPED BELOW FREEZING IN MANY
LOCATIONS WHICH HAVE ALREADY BEGUN THEIR GROWING SEASONS...WHILE
OTHERS (THE EASTERN UINTAS) HAVE ALREADY SEEN A DECENT AMOUNT OF
ACCUMULATING SNOW. A LARGE CLOSED LOW IS CURRENTLY OVER SOUTHEAST
UTAH AND WILL SLOWLY PROGRESS SOUTH TO THE FOUR CORNERS LATER THIS
MORNING. MODELS ARE IN GOOD AGREEMENT THAT SIGNIFICANT SNOW IS
GOING TO FALL AT ELEVATIONS MAINLY HIGHER THAN 9000 FT STARTING
THIS AFTERNOON ACROSS THE WEST CENTRAL COLORADO MOUNTAINS AND WILL
CONTINUE TO FALL OVER THE EASTERN UINTAS. THOUGH WINDS WILL NOT BE
FAVORABLE FOR CONSTANT SNOWFALL DURING THE ENTIRE TIME PERIOD OF
THE WINTER HAZARDS...WHEN THE DIRECTION IS RIGHT COMBINED WITH
LIFTING DUE TO THE PASSING CLOSED LOW...HEAVY WET SNOW WILL PILE
UP QUICKLY AT THESE HIGHER LOCATIONS. HAVE KEPT A CLOSE EYE ON THE
MOISTURE FIELDS OVER THE LAST FEW DAYS AND HAVE SEEN THE FORECAST
MODELS INCREASE MOISTURE FROM THE SOUTH AND NOW INCREASE MOISTURE
ACROSS WESTERN CO AND EASTERN UT AS IT WRAPS AROUND THE SLOWLY
PROGRESSING CLOSED LOW. THE SLOW MOVEMENT AND DYNAMICS OF THE LOW
SHOULD BE EFFECTIVE IN OVERCOMING THE MOUNTAIN SHADOW EFFECT. SPEC
HUMIDITY VALUES ARE NOW BEING PROGGED TO REACH AND EXCEED 4 G/KG
WHICH IS RATHER SIGNIFICANT WITH SUCH A COLD SYSTEM IN APRIL. SNOW
LEVEL IS DEFINITELY A CHALLENGE AND AM EXPECTING NORTHERN COLORADO
VALLEYS TO SEE MAINLY RAIN AND A RAIN/SNOW MIX WITH LITTLE
ACCUMULATION. AN UPTICK IN ACTIVITY IS EXPECTED THIS AFTERNOON AND
EVENING...BUT ALL FORECAST MODELS REALLY PICK UP COVERAGE IN
ACTIVITY FRIDAY AFTERNOON. CONDITIONS NORTH OF I-70 TODAY WILL BE
BREEZY AND WET MUCH OF TODAY. ELSEWHERE WILL RECEIVE SCATTERED
SHOWERS WITH THE EXCEPTION OF THE CENTRAL MOUNTAINS WHICH WILL SEE
DETERIORATING CONDITIONS TODAY.
ADDED NORTHERN SAN JUANS TO A WINTER STORM WATCH STARTING TONIGHT
AS WE ANTICIPATE FLOW CHANGING TO WEST NORTHWESTERLY. STRONG
NORTHERLY FLOW FRIDAY EVENING WILL ALSO BE FAVORABLE FOR THIS AREA
TO RECEIVE HEAVY SNOW IF THE LOW STAYS ON TRACK. CONFIDENCE IS
MODERATE ON CURRENT SOLUTIONS EVEN A COUPLE DAYS OUT DUE TO THE
LOW TRACKING SO SLOWLY ACROSS THE REGION.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 416 AM MDT THU APR 16 2015
MEANDERING LOW WILL CONTINUE TO WREAK HAVOC ON THE FORECAST AS WE
START OFF THIS EXTENDED PERIOD. DEEP NORTHERLY FLOW ON THE BACK
SIDE OF THE...EXPECTED TO BE EXITING LOW PRESSURE SYSTEM...MAY
KEEP LOCALLY HEAVY SNOW FALLING ACROSS THE NORTHWEST SAN JUAN
MOUNTAINS AND OTHER FAVORED NORTH FACING SLOPES IN WESTERN
COLORADO. THIS SYSTEM LOOKS TO LINGER OVER THE AREA UNTIL MIDDAY
SATURDAY...BEFORE A KICKING WAVE DROPS INTO MONTANA LATE SATURDAY
AFTERNOON AND EVENING. THIS SYSTEM SHOULD KICK THE LOW OUT INTO
THE PLAINS WITH SOMEWHAT MOIST NW FLOW HOLDING IN PLACE THROUGH
THE REMAINDER OF THE WEEKEND. SO EXPECT UNSETTLED CONDITIONS TO
CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS WITH ADDITIONAL
LATE SEASON SNOWFALL ANTICIPATED...ESPECIALLY ABOVE THE 9K LEVEL.
SLIGHT INCREASE IN HEIGHTS EXPECTED AS WE MOVE INTO THE NEW WORK
WEEK...WHICH WILL MODIFY TEMPS UP A BIT. HOWEVER...ENOUGH PACIFIC
MOISTURE STREAMING INTO THE REGION TO KEEP ISOLATED TO SCATTERED
POPS ROLLING THROUGHOUT THE PERIOD...GENERALLY FOCUSED ON THE
HIGHER TERRAIN. ANOTHER STRONG CLOSED LOW BEING ADVERTISED BY BOTH
THE GFS AND ECMWF LATE NEXT WEEK PROMISES TO BRING MORE WIDESPREAD
PRECIPITATION TO THE REGION AS WE CLOSE THE WEEK OUT. EXPECT
TEMPS TO BE RUNNING NEAR TO SLIGHTLY BELOW NORMAL THROUGH THIS
PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1054 AM MDT THU APR 16 2015
A STRONG LOW PRESSURE SYSTEM NEAR THE FOUR CORNERS AREA THIS
AFTERNOON AND THIS EVENING...WILL MEANDER SLOWLY INTO SOUTH-
CENTRAL COLORADO BY MIDDAY FRIDAY. EXPECT WIDESPREAD SHOWERS
ACROSS THE REGION BY THIS AFTERNOON...WITH LOCALLY HEAVY SNOW
EXPECTED OVER THE MOUNTAINS THROUGH SATURDAY. SNOW WILL SWITCH
OVER TO RAIN IN THE LOWER VALLEYS AT TIMES THIS AFTERNOON. CIGS
AND VSBY WILL DROP IN SHOWERS WITH AREAS OF MVFR AND IFR CONDS.
THESE POOR CONDITIONS WILL BECOME MORE WIDESPREAD LATER TONIGHT.
MOUNTAINS WILL BECOME OBSCURED... ESPECIALLY NEAR SHOWERS. GUSTY
EASTERLY WINDS CAN BE EXPECTED ACROSS WESTERN COLORADO AND EASTERN
UTAH THROUGH FRIDAY MORNING.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ004-009-
013.
WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR COZ010-012.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING
FOR COZ018.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ021.
UT...WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR UTZ023.
&&
$$
UPDATE...JAD
SHORT TERM...JAM
LONG TERM...JDC
AVIATION...EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
938 AM MDT THU APR 16 2015
.UPDATE...
ISSUED AT 936 AM MDT THU APR 16 2015
GRAND JCT RADAR INDICATED AN AREA OF ENHANCED PRECIPITATION ACROSS
WEST-CENTRAL CO THIS MORNING. MUCH OF THIS PRECIP WAS SNOW PER
PUBLIC REPORTS AND WEBCAM IMAGES. NOT EXPECTING ANY LONG-LASTING
ACCUMULATIONS IN THESE VALLEYS THOUGH PERIODS OF HEAVIER SNOW MAY
TEMPORARILY WHITEN GRASSY SURFACES. HI-RESOLUTION HRRR AND RAP
MODELS SHOW THIS AREA DECREASING...OR AT LEAST SLIDING NORTH AND
NORTHEAST...BY LATE MORNING. EXPECT TO SEE COVERAGE INCREASE ACROSS
ALL OF THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA THIS
AFTERNOON AS CONVECTIVE INSTABILITY KICKS IN EVEN MORE.
LET THE FREEZE WARNING EXPIRE AT 9 AM THIS MORNING. SOME AREAS WHERE
SNOW IS OCCURRING MAY STILL BE IN THE UPPER 20S FOR A BIT LONGER
THOUGH...LIKE DELTA/MONTROSE/PAONIA AREAS. FREEZE WATCH REMAINS
FOR THE CORTEZ-YELLOWJACKET AREA EARLY FRI MORNING.
UPDATE ISSUED AT 613 AM MDT THU APR 16 2015
SOCIAL MEDIA REPORTS OF HOWLING WINDS IN THE STEAMBOAT SPRINGS
AREA HAVE BEEN RECEIVED EARLY THIS MORNING...PEAK GUSTS ON SENSORS
IN THE AREA SHOWING 25-35 MPH SO FAR THIS MORNING. PATTERN IS
SETTING UP FOR A POTENTIAL DOWNSLOPE WIND EVENT IN THIS REGION
LATER THIS AFTERNOON AND TONIGHT. STRONG H7 FLOW AROUND NORTH
SIDE OF THE LOW EXPECTED TO EXCEED 50 KTS AND WE HAVE SEEN THIS
TYPE OF FLOW IN THE PAST GENERATE STRONG DOWNSLOPE WINDS IN THE
STEAMBOAT AND ZIRKEL WILDERNESS AREAS. TRACK OF THE UPPER LOW WILL
PLAY CRITICAL ROLE AND MODELS STILL A BIT OUT OF PHASE IN EXACT
PATH...SO WILL CONTINUE TO MONITOR AND ADVISE LATER SHIFTS OF THIS
POTENTIAL. IN THE MEANTIME...BOOSTED SPEEDS UP A FEW CATEGORIES
FOR TODAY WITH GUSTS UP TO 50 MPH FOR THE HILLS AND GUST TO UP TO 45
FOR THE VALLEYS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 416 AM MDT THU APR 16 2015
SPRING IN THE CENTRAL ROCKIES IS REARING ITS UGLY HEAD AS
TEMPERATURES THIS MORNING HAVE DIPPED BELOW FREEZING IN MANY
LOCATIONS WHICH HAVE ALREADY BEGUN THEIR GROWING SEASONS...WHILE
OTHERS (THE EASTERN UINTAS) HAVE ALREADY SEEN A DECENT AMOUNT OF
ACCUMULATING SNOW. A LARGE CLOSED LOW IS CURRENTLY OVER SOUTHEAST
UTAH AND WILL SLOWLY PROGRESS SOUTH TO THE FOUR CORNERS LATER THIS
MORNING. MODELS ARE IN GOOD AGREEMENT THAT SIGNIFICANT SNOW IS
GOING TO FALL AT ELEVATIONS MAINLY HIGHER THAN 9000 FT STARTING
THIS AFTERNOON ACROSS THE WEST CENTRAL COLORADO MOUNTAINS AND WILL
CONTINUE TO FALL OVER THE EASTERN UINTAS. THOUGH WINDS WILL NOT BE
FAVORABLE FOR CONSTANT SNOWFALL DURING THE ENTIRE TIME PERIOD OF
THE WINTER HAZARDS...WHEN THE DIRECTION IS RIGHT COMBINED WITH
LIFTING DUE TO THE PASSING CLOSED LOW...HEAVY WET SNOW WILL PILE
UP QUICKLY AT THESE HIGHER LOCATIONS. HAVE KEPT A CLOSE EYE ON THE
MOISTURE FIELDS OVER THE LAST FEW DAYS AND HAVE SEEN THE FORECAST
MODELS INCREASE MOISTURE FROM THE SOUTH AND NOW INCREASE MOISTURE
ACROSS WESTERN CO AND EASTERN UT AS IT WRAPS AROUND THE SLOWLY
PROGRESSING CLOSED LOW. THE SLOW MOVEMENT AND DYNAMICS OF THE LOW
SHOULD BE EFFECTIVE IN OVERCOMING THE MOUNTAIN SHADOW EFFECT. SPEC
HUMIDITY VALUES ARE NOW BEING PROGGED TO REACH AND EXCEED 4 G/KG
WHICH IS RATHER SIGNIFICANT WITH SUCH A COLD SYSTEM IN APRIL. SNOW
LEVEL IS DEFINITELY A CHALLENGE AND AM EXPECTING NORTHERN COLORADO
VALLEYS TO SEE MAINLY RAIN AND A RAIN/SNOW MIX WITH LITTLE
ACCUMULATION. AN UPTICK IN ACTIVITY IS EXPECTED THIS AFTERNOON AND
EVENING...BUT ALL FORECAST MODELS REALLY PICK UP COVERAGE IN
ACTIVITY FRIDAY AFTERNOON. CONDITIONS NORTH OF I-70 TODAY WILL BE
BREEZY AND WET MUCH OF TODAY. ELSEWHERE WILL RECEIVE SCATTERED
SHOWERS WITH THE EXCEPTION OF THE CENTRAL MOUNTAINS WHICH WILL SEE
DETERIORATING CONDITIONS TODAY.
ADDED NORTHERN SAN JUANS TO A WINTER STORM WATCH STARTING TONIGHT
AS WE ANTICIPATE FLOW CHANGING TO WEST NORTHWESTERLY. STRONG
NORTHERLY FLOW FRIDAY EVENING WILL ALSO BE FAVORABLE FOR THIS AREA
TO RECEIVE HEAVY SNOW IF THE LOW STAYS ON TRACK. CONFIDENCE IS
MODERATE ON CURRENT SOLUTIONS EVEN A COUPLE DAYS OUT DUE TO THE
LOW TRACKING SO SLOWLY ACROSS THE REGION.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 416 AM MDT THU APR 16 2015
MEANDERING LOW WILL CONTINUE TO WREAK HAVOC ON THE FORECAST AS WE
START OFF THIS EXTENDED PERIOD. DEEP NORTHERLY FLOW ON THE BACK
SIDE OF THE...EXPECTED TO BE EXITING LOW PRESSURE SYSTEM...MAY
KEEP LOCALLY HEAVY SNOW FALLING ACROSS THE NORTHWEST SAN JUAN
MOUNTAINS AND OTHER FAVORED NORTH FACING SLOPES IN WESTERN
COLORADO. THIS SYSTEM LOOKS TO LINGER OVER THE AREA UNTIL MIDDAY
SATURDAY...BEFORE A KICKING WAVE DROPS INTO MONTANA LATE SATURDAY
AFTERNOON AND EVENING. THIS SYSTEM SHOULD KICK THE LOW OUT INTO
THE PLAINS WITH SOMEWHAT MOIST NW FLOW HOLDING IN PLACE THROUGH
THE REMAINDER OF THE WEEKEND. SO EXPECT UNSETTLED CONDITIONS TO
CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS WITH ADDITIONAL
LATE SEASON SNOWFALL ANTICIPATED...ESPECIALLY ABOVE THE 9K LEVEL.
SLIGHT INCREASE IN HEIGHTS EXPECTED AS WE MOVE INTO THE NEW WORK
WEEK...WHICH WILL MODIFY TEMPS UP A BIT. HOWEVER...ENOUGH PACIFIC
MOISTURE STREAMING INTO THE REGION TO KEEP ISOLATED TO SCATTERED
POPS ROLLING THROUGHOUT THE PERIOD...GENERALLY FOCUSED ON THE
HIGHER TERRAIN. ANOTHER STRONG CLOSED LOW BEING ADVERTISED BY BOTH
THE GFS AND ECMWF LATE NEXT WEEK PROMISES TO BRING MORE WIDESPREAD
PRECIPITATION TO THE REGION AS WE CLOSE THE WEEK OUT. EXPECT
TEMPS TO BE RUNNING NEAR TO SLIGHTLY BELOW NORMAL THROUGH THIS
PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 416 AM MDT THU APR 16 2015
A STRONG LOW PRESSURE SYSTEM WILL BE DROPPING SOUTH INTO THE FOUR
CORNERS AREA TODAY AND WILL MEANDER SLOWLY ENE ACROSS COLORADO FOR
THE NEXT 24 HOURS. EXPECT WIDESPREAD SHOWERS TO DEVELOP ACROSS THE
REGION BY THIS AFTERNOON...WITH LOCALLY HEAVY SNOW EXPECTED OVER
THE MOUNTAINS THROUGH SATURDAY. CIGS WILL BE DROPPING THROUGHOUT
THE REGION WITH AREAS OF MVFR AND IFR CONDS ANTICIPATED LATER
TONIGHT. MOUNTAINS WILL BECOME OBSCURED...ESPECIALLY NEAR SHOWERS.
GUSTY EASTERLY WINDS CAN BE EXPECTED ACROSS WESTERN COLORADO AND
EASTERN UTAH THROUGH FRIDAY MORNING.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ004-009-
013.
WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR COZ010-012.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING
FOR COZ018.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ021.
UT...WINTER STORM WARNING UNTIL 6 AM MDT SATURDAY FOR UTZ023.
&&
$$
UPDATE...JAD
SHORT TERM...JAM
LONG TERM...JDC
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
430 AM EDT THU APR 16 2015
.SYNOPSIS...08Z WATER VAPOR AND H4 RAP ANALYSIS SHOW TWO DISTINCT
AND SEPARATE UPPER LEVEL FLOWS ACROSS NORTH AMERICA THIS MORNING.
THE NORTHERN STREAM FLOW HAS SHIFTED WELL TO THE NORTH AND NOW RUNS
IN A GENERALLY ZONAL CONFIGURATION TO THE NORTH OF THE US/CANADIAN
BORDER. A SECOND BELT OF SOUTHERN STREAM WESTERLIES CROSSES FROM THE
CENTRAL PACIFIC...OVER MEXICO...AND ACROSS THE GULF OF MEXICO INTO
THE SOUTHEASTERN CONUS/FL PENINSULA. THIS SOUTHERN STREAM FLOW IS
TRANSPORTING ABUNDANT MID/UPPER LEVEL MOISTURE INTO THE REGION PER
WV IMAGERY. BETWEEN THESE TO BELTS OF WESTERLIES...THE FLOW BECOMES
MUCH WEAKER...WITH A LARGE CUTOFF LOW NOW TRAPPED OVER THE INTER-
MOUNTAIN WEST...AND DOWNSTREAM RIDING OVER THE EASTERN CONUS. THE
UPPER LOW IS CURRENTLY CENTERED AND SPINNING NEAR THE 4-CORNERS
REGION...AND IS NOT SHOWN TO MOVE MUCH AT ALL DURING THE NEXT 24
HOURS BY THE MAJORITY OF THE AVAILABLE GUIDANCE.
WITHIN THE SOUTHERN STREAM FLOW WE SEE A SERIES OF WEAK IMPULSES
RIDING ALONG THE NORTHERN GULF COAST AHEAD OF AN 80-100KT JET
STREAK...EXTENDING OVER NORTHERN MEXICO TO THE WESTERN GULF OF
MEXICO. SYNOPTIC LIFT ASSOCIATED WITH THESE DISTURBANCES...AND ALONG
THE LEADING NOSE OF THE JET ARE FORCING PERIODIC PULSES OF
CONVECTION OVER THE NORTH-CENTRAL GULF OF MEXICO. SOME OF THIS LIFT
IS NOW BEGINNING TO REACH AS FAR EAST AS THE NE GOMEX WHERE HIGHER
LEVEL RADAR RETURNS ARE BEGINNING TO BLOSSOM SOUTH OF APALACHICOLA.
THE RAP/HRRR SEEM TO HAVE A DECENT HANDLE ON THIS ACTIVITY AND HAVE
FOLLOWED THEIR ENSEMBLE SOLUTION CLOSELY FOR THE RAIN CHANCES INTO
OUR NORTHERN MARINE ZONES/LEVY COUNTY THROUGH THE NEXT 4-8 HOURS.
AT THE SURFACE...HIGH PRESSURE WEDGING DOWN THE EASTERN SEABOARD
INTO THE SOUTHEAST CONUS HAS PUSHED A WEAK FRONTAL BOUNDARY DOWN
INTO NORTH-CENTRAL FLORIDA. THE BOUNDARY IS SUBTLE...BUT CAN BE
FOUND MOST EASILY BY SURFACE DEWPOINT ANALYSIS...WHERE SLIGHTLY
"DRIER" AIR HAS WORKED INTO AREAS NORTH OF THE I-4 CORRIDOR. THIS
QUASI-STATIONARY BOUNDARY IS LIKELY TO BE THE FOCUS (ALONG WITH
EVENTUAL SEA-BREEZE INTERACTIONS) FOR NUMEROUS SHOWERS AND STORMS
OVER PORTIONS OF THE REGION DURING THE SECOND HALF OF TODAY.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY...
GENERALLY SPEAK THE MAJORITY OF THE SYNOPTIC LIFT AND ASSOCIATED
CONVECTION WITH THE SOUTHERN STREAM IMPULSES WILL REMAIN TO OUR
NORTHWEST TODAY. HOWEVER...THE SOUTHERN STREAM WILL CONTINUE TO
PROVIDE ABUNDANT COLUMN MOISTURE. THE SHOWERS AND STORMS IN OUR
FORECAST AREA WILL BE RELATED TO LOWER LEVEL FOCUS ALONG A QUASI-
STATIONARY FRONTAL BOUNDARY STRETCHED ACROSS NORTH-CENTRAL
FLORIDA...AND ITS EVENTUAL INTERACTION WITH ANY SEA-BREEZE THAT IS
ABLE TO BECOME ESTABLISHED. THE SEA-BREEZE SHOULD BE MOST DEFINED TO
THE SOUTH OF THE FRONTAL BOUNDARY FROM THE TAMPA BAY AREA...AND
ALONG THE SUN COAST. FOR THE MORNING HOURS...WILL BE TRACKING SHOWER
ACTIVITY CROSSING THE NORTHEAST GULF OF MEXICO AHEAD OF A LEADING
SOUTHERN STREAM IMPULSE. AS MENTIONED IN THE SYNOPSIS...THE LATEST
RAP/HRRR SEEM TO BE HANDLING THE CURRENT CONVECTION FAIRLY WELL AND
FOLLOWED THEIR SOLUTIONS THIS MORNING...BRINGING CHANCE POPS INTO
LEVY COUNTY. BOTH SHOW THIS ACTIVITY JUST BARELY REACHING LEVY...BUT
A SLIGHT SOUTHERN BIAS TO THE RADAR RETURNS COMPARED TO THE GUIDANCE
SUGGESTS THAT THEY MAY BE INITIALLY TOO FAR NORTH. A FEW OTHER
SHOWERS HAVE BEEN FORMING EARLY THIS MORNING OVER LEE COUNTY ALONG A
RESIDUAL OUTFLOW BOUNDARY FROM WEDNESDAY EVENING CONVECTION. THESE
SHOWERS ARE FINALLY PASSING OFF THE COAST INTO THE GULF.
TOWARD MIDDAY AND INTO THE AFTERNOON HOURS...CONVECTION ALLOWING
GUIDANCE AND PARAMETERIZED GUIDANCE ENSEMBLES ALL SUGGEST A RATHER
ACTIVE SECOND HALF OF THE DAY IN TERMS OF SHOWERS AND STORMS.
ACTUALLY AM VERY IMPRESSED WITH THE DEGREE OF AGREEMENT WITHIN THE
CONVECTION ALLOWING MODELS AS TO STORM INITIATION AND EVOLUTION.
APPEARS STORMS WILL BEGIN TO FIRE BY EARLY AFTERNOON ALONG THE
FRONTAL BOUNDARY GENERALLY ALONG THE I-4 CORRIDOR...AND BY THAT I
JUST MEAN CENTRAL FLORIDA. BY LATER IN THE AFTERNOON/EARLY
EVENING...APPEARS STORMS BEGIN TO ALIGN MORE NORTH TO SOUTH PARALLEL
TO THE COAST...WITH THE HEAVIEST ACTIVITY SHIFTING INTO OUR SOUTH-
CENTRAL ZONES...WHERE THE FRONTAL ZONES MOST ACTIVELY INTERACTS WITH
THE SUNCOAST SEA-BREEZE. THIS IS A TOUGH FORECAST ALONG THE
IMMEDIATE COAST AS THE SEA-BREEZE IS NOT STRONG TODAY...BUT MAY BE
JUST ENOUGH TO KEEP CONVECTION AWAY FROM THE BEACHES. FOR NOW...HAVE
THE HIGHEST POPS ALONG AND INLAND FORM I-75...BUT CERTAINLY
EXPECTING TO SEE SOME STORMS FURTHER WEST TO THE COAST...ESPECIALLY
FROM THE TAMPA BAY AREA...UP INTO PASCO/HERNANDO COUNTIES. STORMS
SHOULD EVENTUALLY EVOLVE FURTHER INLAND AND SOUTH AS THE EVENING
PROGRESSES...GIVEN THE FORECAST STORM MOTION BY THE GFS/NAM/RAP. OF
BIGGEST CONCERN LATER TODAY IS THIS STORM MOTION AND AVAILABLE
MOISTURE. NAM/GFS BOTH SHOWING PW VALUES AROUND 2" OVER SOUTH-
CENTRAL ZONES...WITH A SLOW STORM MOTION ONLY AROUND 5 KNOTS. THIS
IS CONCERNING FOR HEAVY RAIN POTENTIAL...ESPECIALLY GIVEN THAT
PORTIONS OF POLK/HIGHLANDS COUNTIES ALREADY RECEIVED SIGNIFICANT
RAINFALL THIS WEEK. WILL NEED TO MONITOR STORMS CLOSELY FOR
LOCALIZED FLOODING POTENTIAL. LOCAL HIRES GUIDANCE HAVE ALSO BEEN
SHOWING FOR SEVERAL RUNS FAIRLY IMPRESSIVE UPDRAFT VELOCITIES WITH
THE ACTIVITY LATER TODAY...ON THE ORDER OF 15 M/S. THESE ARE DECENT
VALUES FOR SEA-BREEZE STORMS...ESPECIALLY THIS TIME OF YEAR. GIVEN
THE AVAILABLE MOISTURE AND POTENTIAL FOR POTENT UPDRAFTS...PRECIP
LOADING AND DOWNDRAFT WIND GUST THREAT WITH THE STRONGER STORMS WILL
ALSO NEED TO BE MONITORED CLOSELY.
CONVECTION IS LIKELY TO LINGER WELL INTO THE LATE EVENING HOURS OVER
OUR SOUTH-CENTRAL ZONES GIVEN THE NEARBY FRONTAL FOCUS...BUT SHOULD
BE ENDING EARLIER OVER THE REST OF THE FORECAST AREA. THE SECOND
HALF OF THE NIGHT APPEARS MUCH QUIETER...AS WOULD BE EXPECTED WITH
THE LOSS OF DIURNAL HEATING. ONE IMPULSE AFTER ANOTHER WILL BE
MOVING ALONG THE NORTHERN GULF COAST...AND ANY OF THESE MAY THREATEN
OUR FAR NORTHERN NATURE COAST ZONES (LEVY/CITRUS) WITH A ROUND OF
SHOWER. CURRENTLY THE GUIDANCE SEEMS TO GRABBING ONTO ANOTHER ONE OF
THESE ROUNDS LATE TONIGHT. THE IMPULSES ARE SO SUBTLE AND DEPENDENT
ON JUST THE RIGHT DOWNSTREAM CONVECTIVE ACTIVITY...THAT FEEL GOING
TO AGGRESSIVE WITH POPS AT THIS POINT IS UNNECESSARY. WILL LET THE
DAYSHIFT REEVALUATE FOR THESE NORTHERN ZONES AFTER 06Z.
FRIDAY... BOUNDARY BEGINS TO DECAY...WITH A WEAK GRADIENT ALLOWING
FOR A MORE UNIFORM SEA-BREEZE TO DEVELOP ALONG THE FL WEST COAST.
1000-700MB FLOW FROM THE W/NW WOULD SUGGEST THIS SEABREEZE MOVE
INLAND MORE QUICKLY...WITH EAST/WEST COAST SEA-BREEZE INTERACTIONS
OCCURRING OVER OUR FAR INLAND ZONES OR EVEN OVER TOWARD THE I-95
CORRIDOR. WITH THIS IN MIND...OVERALL RAIN CHANCES APPEAR LOWER FOR
THE I-75 CORRIDOR...ESPECIALLY THIS CORRIDOR SOUTH OF THE TAMPA BAY
AREA. HIGHEST POPS 50-60% WILL THEREFORE EXIST WELL INLAND OVER
SOUTHERN AREAS...AND ALSO ACROSS THE NATURE COAST IN CLOSER
PROXIMITY TO ANY PASSING SYNOPTIC SUPPORT.
&&
.LONG TERM (SATURDAY THROUGH NEXT WEDNESDAY)...
THE PERIOD BEGINS WITH AN UPPER LEVEL CUT-OFF LOW NEAR THE FOUR
CORNERS REGION AND RIDGING FROM THE GULF OF MEXICO TO NEAR THE GREAT
LAKES. A FRONTAL BOUNDARY STRETCHES ALONG THE EASTERN GULF COAST AND
THROUGH NORTHERN FL WHILE MID-ATLANTIC HIGH PRESSURE RIDGES SOUTH
INTO FL WITH A WEAK GRADIENT. THROUGH THE WEEKEND THE CUT-OFF LOW
TRACKS UP TO THE GREAT LAKES...WITH A SURFACE LOW FORMING AND
TRAILING A COLD FRONT THAT ARCS THROUGH THE SOUTHEAST U.S. AND INTO
THE GULF...AND OPENS INTO A BROAD TROUGH DOWN INTO THE GULF. THE
UPPER RIDGE SLIDES OFF THE EASTERN SEABOARD WHILE THE FRONTAL
BOUNDARY LIFTS NORTHWARD. A MOIST AIRMASS REMAINS IN PLACE AS THE
FRONTAL BOUNDARY DEPARTS AND LOW LEVEL FLOW SHIFTS FROM EASTERLY TO
SOUTHERLY...BUT WITH AFTERNOON SEAS BREEZES..AND INCREASE IN
STRENGTH AS THE COLD FRONT MOVES INTO THE GULF. THIS WILL RESULT IN
SHOWERS AND THUNDERSTORMS WITH THE BEST COVERAGE IN THE
AFTERNOONS...IN THE CHANCE RANGE.
FOR MON-WED THE UPPER LEVEL TROUGH SLOWLY SHIFTS EAST...DOMINATING
THE EASTERN U.S. WHILE THE SURFACE LOW EJECTS INTO CANADA AND DRAGS
THE COLD FRONT OUT OVER THE ATLANTIC...BUT WITH THE SOUTHERN END
SLOWLY SAGGING SOUTHWARD ACROSS FL. SOUTHERLY AND SOUTHWESTERLY FLOW
WILL INCREASE EARLY IN THE PERIOD PROVIDING ADDITIONAL MOISTURE
WHICH WITH THE APPROACHING FRONT WILL RESULT IN SHOWERS AND
THUNDERSTORMS..WITH CHANCE TO LIKELY POPS MON AS THE FRONT PUSHES
INTO THE AREA. RAIN CHANCES BEGINS TO TREND DOWN TUE-WED AS THE
FRONT SLIDES SOUTH AND WEAKENS.
TEMPERATURES START OFF WELL ABOVE NORMAL BUT GRADUALLY DROP BY MID
WEEK. HIGHS DECREASE TO NEAR NORMAL BUT THE OVERNIGHT LOWS WILL
CONTINUE ON THE WARM SIDE.
&&
.AVIATION... VFR CONDITIONS PREVAILING ACROSS WEST-CENTRAL AND MOST
OF SOUTHWEST FLORIDA EARLY THIS MORNING. HAVE SEEN A FEW SHOWERS
AROUND KFMY/KRSW WITH BRIEF MVFR CIGS...HOWEVER THIS ACTIVITY SHOULD
DIMINISH BEFORE SUNRISE. AVIATION CONCERNS TODAY WILL CENTER AROUND
THE DEVELOPMENT OF SCT TO NMRS SHOWERS AND THUNDERSTORMS FOR THE
AFTERNOON/EVENING HOURS. THE GREATEST COVERAGE OF STORMS WILL BE
INLAND FROM THE I-75 CORRIDOR AFTER 17Z...ALTHOUGH EVEN TERMINALS
ALONG I-75 WILL HAVE THE POTENTIAL FOR A STORM.
&&
.MARINE... A WEAK FRONTAL BOUNDARY WILL DIP SOUTH INTO NORTHERN
FLORIDA AND THE FAR NORTHEAST GULF OF MEXICO TODAY AND REMAIN IN
PLACE THROUGH FRIDAY. THIS BOUNDARY WILL THEN DECAY FRIDAY NIGHT
INTO SATURDAY AS WEAK HIGH PRESSURE BUILDS SOUTH INTO THE REGION
FROM THE NORTH. WINDS AND SEAS WILL REMAIN LOW THROUGH SATURDAY WITH
SPEEDS GENERALLY LESS THAN 10-15 KNOTS. THE BEST POTENTIAL FOR
DEFINED SEA-BREEZE DEVELOPMENT NEAR THE COAST THE NEXT TWO DAYS WILL
BE TO THE SOUTH OF THE FRONTAL BOUNDARY...MAINLY SOUTH OF TARPON
SPRINGS.
&&
.FIRE WEATHER... A WEAK FRONT WILL DIP INTO NORTHERN FLORIDA TODAY
AND THEN REMAIN NEARLY STATIONARY THROUGH FRIDAY. NO SIGNIFICANT
FIRE WEATHER CONCERNS ARE EXPECTED THROUGH THE END OF THE WEEK.
RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL LEVELS.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BECOME RATHER NUMEROUS
OVER INTERIOR CENTRAL AND SOUTH-CENTRAL ZONES LATER THIS AFTERNOON
AND EVENING WITH MORE SCATTERED VARIETY STORMS ELSEWHERE. SHOWERS
AND STORMS SHOULD AGAIN BE MOST NUMEROUS WELL INLAND FROM THE COAST
ON FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 86 72 85 71 / 50 30 40 20
FMY 89 71 88 71 / 40 40 20 10
GIF 87 69 86 69 / 80 50 60 20
SRQ 83 71 83 70 / 30 20 30 20
BKV 86 67 85 66 / 60 40 50 20
SPG 86 74 84 73 / 40 20 30 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/AVIATION/FIRE WX...MROCZKA
LONG TERM/DECISION SUPPORT SERVICES...RUDE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1022 PM EDT FRI APR 17 2015
.SYNOPSIS...
UNSETTLED AND WET WEATHER PATTERN WILL CONTINUE THROUGH THE
WEEKEND INTO MONDAY. A COLD FRONT WILL MOVE ACROSS THE AREA ON
MONDAY AND HIGH PRESSURE WILL BUILD OVER THE AREA TUESDAY AND
WEDNESDAY BRINGING FAIR WEATHER.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
HIGH PRESSURE OVER THE MID-ATLANTIC STATES WITH WEAK LOW PRESSURE
OFF THE SC COAST. AN LARGE AREA OF MAINLY LIGHT RAIN EXTENDS FROM
SOUTHERN GA TO CENTRAL SC. EXPECT THE WEAK LOW LEVEL WEDGE TO
REMAIN OVERNIGHT AIDED BY THE ADDITIONAL RAINFALL ANTICIPATED.
MAIN ISSUE IS PRECIPITATION POTENTIAL. APPEARANCE OF SIGNIFICANT
UPPER SHORT WAVE...CURRENTLY SEEN ON SATELLITE WATER VAPOR IMAGERY
OVER AL. THIS FEATURE WILL TRACK SLOWLY TO THE EAST OVERNIGHT.
GIVEN THE LATEST HRRR GUIDANCE...WILL KEEP LIKELY OR GREATER POPS OVER THE
WESTERN AND CENTRAL COUNTIES UNTIL AROUND 06Z...WITH CHANCE POPS
ELSEWHERE. AFTER 06Z...MAINLY CHANCE POPS ACROSS THE AREA. LOW
CONFIDENCE ON EXTENT OF FOG DUE TO PRECIP CHANCES AND CONSIDERABLE
CLOUDINESS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
LATEST MODEL RUNS BRING A CHANGE TO THE FORECAST. IT APPEARS THAT
AN UPPER IMPULSE WILL MOVE ACROSS THE AREA TONIGHT AND THIS WILL
BRING AN ENHANCED CHANCE OF SHOWERS THAT WILL LINGER INTO
SATURDAY. HIGH PRESSURE WILL NOSE SOUTH OVER THE AREA WITH WHAT
LOOKS LIKE A CONTINUATION OF THE WEDGE. MODELS KEEP LOW LEVEL RH
HIGH SO EXPECT MOSTLY CLOUDY ON SATURDAY. WILL KEEP POPS IN THE
MORNING IN THE 30 TO 50 PERCENT RANGE AND AROUND 30 PERCENT IN THE
AFTERNOON INTO THE EVENING. LATEST GUIDANCE IS SIGNIFICANTLY
COOLER WITH SATURDAY MAX TEMPS AND HAVE LOWERED THE FORECAST INTO
LOWER TO MID 70S.
MODELS ARE AND FASTER MOVING THE NEXT SYSTEM INTO THE AREA ON
SATURDAY NIGHT AND CONTINUING INTO SUNDAY AS LARGE UPPER LOW OVER
THE WESTERN US OPENS AND MOVES EAST. EXPECT WIDESPREAD RAIN...AND
POSSIBLY SOME EMBEDDED THUNDERSTORMS FROM LATE SATURDAY NIGHT
THROUGH MOST OF SUNDAY. HAVE MAX TEMPS UPPER 60S NORTH TO UPPER
70S SOUTH.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
DEEP MOISTURE AND ISENTROPIC LIFT MOVE NORTHEAST OF THE AREA ON
SUNDAY NIGHT BUT APPROACHING COLD FRONT AND UPPER LEVEL WAVE WILL
KEEP THE CHANCE OF RAIN THROUGH MONDAY. EXPECT POSSIBLY A LINE OF
CONVECTION WITH THE COLD FRONT ON MONDAY. HIGH PRESSURE BUILDS
OVER THE REGION TUESDAY AND WEDNESDAY BRINGING A REPRIEVE FROM THE
UNSETTLED PATTERN. UPPER FLOW BECOMES ZONAL FOR THE SECOND HALF OF
THE WEEK WHICH IS AN MORE UNCERTAIN WEATHER PATTERN. THERE ARE
SOME INDICATIONS OF LOW LEVEL MOISTURE RETURNING ON THURSDAY AND
FRIDAY BUT GIVEN AN UNCERTAIN ZONAL PATTERN ALONG WITH BEING
SEVERAL DAYS OUT WILL KEEP THE POPS LOW FOR NOW.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
WEDGE CONDITIONS APPEAR TO HAVE WEAKENED AT LEAST TEMPORARILY AS
CIGS HAVE BECOME VFR AT ALL TERMINALS AS SOME LIGHT RAIN MOVES
THROUGH THE REGION ASSOCIATED WITH AN UPPER DISTURBANCE CROSSING
AL/GA. MODEL GUIDANCE AND TIME HEIGHT FORECASTS AND HI RES MODEL
DATA INDICATING THAT THIS PERIOD OF VFR CIGS WILL BE SHORT LIVED
AND CIGS WILL FALL BACK DOWN TO IFR BY 04Z ALL TERMINALS WITH THE
LOSS OF HEATING AND LIGHT RAIN FALLING. LIGHT RAIN EXPECTED TO
LINGER THROUGH THE NIGHT UNTIL THE SHORTWAVE PASSES AND EXPECT
CIGS TO FALL INTO LIFR DURING THE PREDAWN HOURS AFTER 08Z-09Z.
VSBYS ARE MORE DIFFICULT AND HAVE LOWER CONFIDENCE IN THAT
FORECAST. GRADUAL IMPROVEMENT EXPECTED ON SATURDAY WITH A BRIEF
PERIOD OF DRY WEATHER EXPECTED BEFORE YET ANOTHER ROUND OF
PRECIPITATION BY SUNDAY.
.EXTENDED AVIATION OUTLOOK...
EXPECT INCREASING RAIN CHANCES...AND ASSOCIATED
RESTRICTIONS...SATURDAY NIGHT...SUNDAY INTO SUNDAY NIGHT. THUNDER
AND HEAVY RAIN WILL BE POSSIBLE SUNDAY/SUN NT. SCATTERED
THUNDERSTORMS POSSIBLE MONDAY AFTERNOON AND EVENING. NO IMPACTS TO
AVIATION EXPECTED MONDAY NIGHT THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
259 PM CDT THU APR 16 2015
.UPDATE...
1113 AM CDT
TEMPERATURE AND PRECIPITATION TRENDS APPEAR TO BE ON TRACK LATE
THIS MORNING UNDER SIGNIFICANT CLOUD COVER WITH A FEW AREAS OF
PATCHY DRIZZLE MAINLY SOUTH OF THE LAKE. LIGHT WINDS UNDER THE
CLOUD DECK ARE NOT ASSISTING THE MIXING OUT OF LOW LEVEL
MOISTURE...BUT RAP RH TRENDS AND RECENT SATELLITE LOOPS SUGGEST
THE CLOUDS WILL BE SCATTERING OUT LATER THIS AFTERNOON WHICH
WOULD ALLOW TEMPERATURES TO CLIMB RAPIDLY AS SEEN ACROSS NORTHWEST
ILLINOIS AND EASTERN IOWA. FOR AREAS THAT DO NOT MANAGE TO CLEAR
AS EARLY...HIGHS MAY NEED TO BE TWEAKED DOWNWARD A FEW DEGREES.
LENNING
&&
.SHORT TERM...
304 AM CDT
THROUGH FRIDAY...
COMPACT BUT STRONG VORT IS MOVING NORTHWARD ACROSS ILLINOIS THIS
MORNING AND DRIVING AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS
NORTHWARD ACROSS FAR EASTERN ILLINOIS AND WESTERN INDIANA EARLY THIS
MORNING. THIS ACTIVITY WILL AFFECT CHICAGO AREA AND NW INDY INTO THE
EARLY MORNING HOURS BEFORE MOVING OUT OF THE REGION. FAIRLY
EXTENSIVE CLOUD COVER UPSTREAM AND WITH RAIN LIKELY TO FURTHER
SATURATED THE COLUMN AM CONCERNED THAT CLOUD COVER COULD BE FAIRLY
PREVALENT ACROSS ESPECIALLY EASTERN PORTIONS OF THE CWA INTO AT
LEAST THE FIRST PART OF THE AFTERNOON WHICH SHOULD SLOW TEMPERATURE
RISE AND LIKELY KEEP TEMPS FROM GETTING ABOVE GUIDANCE TODAY UNLIKE
THE PAST COUPLE DAYS.
IN THE WAKE OF THIS MORNING`S SHORTWAVE LOOK FOR HEIGHT RISES AS
UPPER RIDGING BUILDS INTO THE REGION IN ADVANCE OF THE BIG WESTERN
CUT-OFF LOW. RISING HEIGHTS AND WARMING LOW/MID LEVEL LOOK TO SET
THE STAGE FOR A COUPLE OF RATHER TOASTY DAYS AWAY FROM THE
LAKEFRONT. PROGGED 925MB TEMPS INTO THE MID TEENS CELSIUS SUPPORT
HIGHS AROUND 80F AND HAVE BUMPED TEMPS IN THE GRIDS UPWARD TOWARD
THE DIRECTION...AND GIVEN THE RECENT COOL BIAS IN GUIDANCE ITS
POSSIBLE THAT THESE FORECAST GRIDS COULD END UP TOO COOL STILL WITH
80F+ ACROSS MOST OF THE CWA FRIDAY AND SATURDAY.
IZZI
&&
.LONG TERM...
304 AM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
GUIDANCE IS REMAINS IN RELATIVELY GOOD AGREEMENT ON THE EJECTION OF
THE BIG WESTERN CLOSED LOW WITH SHOWERS AND THUNDERSTORMS IN ADVANCE
OF THIS SYSTEM EXPECTED TO ARRIVE PROBABLY SUNDAY AND COULD STICK
AROUND AT TIMES INTO SUNDAY NIGHT. GFS REMAINS IS ON THE FASTER END
OF THE GUIDANCE ENVELOPE...BUT GIVEN THE TENDENCY FOR THESE SYSTEMS
TO BE SLOWER THAN PROGGED HAVE KEPT POPS BELOW GUIDANCE SAT NIGHT
MORE IN LINE WITH THE SLOWER GEM SOLUTION.
THE WESTERN CUT OFF LOW IS PROGGED TO PHASE WITH AMPLIFYING NORTHERN
STREAM LONG TROUGH THAT LOOKS TO STALL OUT OVER THE GREAT LAKES
REGION NEXT WEEK. THIS WILL RESULT IN AN END TO THE ABOVE AVERAGE
TEMPERATURES THAT HAVE DOMINATED MUCH OF THIS MONTH...BUT LOOKS TO
BE A FAIRLY DRY PATTERN THROUGH THURSDAY.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT AND VARIABLE WINDS FAVORING EAST AND NORTHEAST THROUGH THE
AFTERNOON.
MDB
//DISCUSSION...UPDATED 18Z...
MVFR LEVEL CLOUDS ARE QUICKLY ERODING LEAVING A VFR DECK OF AROUND
6000 FT. THIS DECK WILL MOVE DRIFT EAST AND PROBABLY ERODE A BIT
THROUGH THE AFTERNOON WITH SOME STRATO CU DEVELOPING ON THE
FRINGES...WHICH WOULD ALSO BE VFR. OTHERWISE LIGHT AND VARIABLE
WINDS WILL BE THE RULE THROUGH THE AFTERNOON AND EVEN THE REST OF
THE NIGHT. EXPECT THAT ORD/MDW WILL FAVOR AN EAST TO NORTHEAST
DIRECTION THANKS TO LAKE INFLUENCES BUT STILL SEE QUITE A BIT OF
VARIABILITY. GYY WOULD LIKELY BE NORTH TO NORTHEAST WITH
VARIABILITY. MANY AREAS WILL PROBABLY EVEN GO CALM AT TIMES. THERE
MAY BE SOME FOG THAT DEVELOPS TONIGHT BUT GIVEN THE DRY CONDITIONS
OF THE PAST FEW DAYS AND ONLY SOME SPOTTY SHOWERS/DRIZZLE THIS
MORNING THE POTENTIAL IS PRETTY LOW.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND FORECAST.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR. WX NIL. SOUTHEAST WINDS LESS THAN 10 KT.
SATURDAY...VFR...THEN SLIGHT CHANCE SHRA/MVFR AFTER MIDNIGHT. EAST
WINDS 10-15 KT.
SUNDAY...LIKELY SHRA/CHANCE TSRA. MVFR POSSIBLE. EAST WINDS 10-15
KT...BECMG NORTHWEST LESS THAN 10 KT OVERNIGHT.
MONDAY...CHANCE SHRA MONDAY...SLIGHT CHANCE SHRA OVERNIGHT. MVFR
POSSIBLE. WEST TO NORTHWEST WINDS 10-15 KT.
TUESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS 15-20KT
TUESDAY...DIMINISHING TO 5-10 KT OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS LESS THAN 10
KT.
KREIN
&&
.MARINE...
304 AM CDT
A RELATIVELY QUIET PERIOD OF WEATHER IS EXPECTED FOR LAKE MICHIGAN
FOR THE NEXT SEVERAL DAYS. HIGH PRESSURE CENTERED OVER SOUTHERN
QUEBEC WILL MOVE OFF THE NEW ENGLAND COAST TODAY...AS LOW PRESSURE
OVER NORTHERN ONTARIO MOVES ACROSS JAMES BAY. MEANWHILE...LOW
PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY DRIFT SOUTHEAST. WITH
A WEAK PRESSURE GRADIENT OVER THE LAKE...LIGHT WINDS WILL COVER
THE OPEN WATERS WHILE ONSHORE FLOW AND A LAKE BREEZE DEVELOP OVER
THE NEARSHORE WATERS TODAY. A SIMILARLY SETUP IS EXPECTED FOR
FRIDAY...BUT THEN A DEEPENING LOW WILL PASS TO THE NORTH OF LAKE
SUPERIOR FRIDAY EVENING WITH AN ASSOCIATED COLD FRONT PUSHING
SOUTH DOWN LAKE MICHIGAN FRIDAY NIGHT...ALLOWING FOR STRENGTHENING
NORTH TO NORTHEAST WINDS TO DEVELOP OVER THE LAKE FOLLOWING THE
FROPA...BUT DO NOT EXPECT WINDS TO EXCEED 20-25 KT. HIGH PRESSURE
WILL THEN BUILD SOUTHEAST ACROSS THE GREAT LAKES AND ONTARIO
FRIDAY NIGHT INTO SATURDAY.
&&
.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/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1210 PM CDT THU APR 16 2015
.UPDATE...
1113 AM CDT
TEMPERATURE AND PRECIPITATION TRENDS APPEAR TO BE ON TRACK LATE
THIS MORNING UNDER SIGNIFICANT CLOUD COVER WITH A FEW AREAS OF
PATCHY DRIZZLE MAINLY SOUTH OF THE LAKE. LIGHT WINDS UNDER THE
CLOUD DECK ARE NOT ASSISTING THE MIXING OUT OF LOW LEVEL
MOISTURE...BUT RAP RH TRENDS AND RECENT SATELLITE LOOPS SUGGEST
THE CLOUDS WILL BE SCATTERING OUT LATER THIS AFTERNOON WHICH
WOULD ALLOW TEMPERATURES TO CLIMB RAPIDLY AS SEEN ACROSS NORTHWEST
ILLINOIS AND EASTERN IOWA. FOR AREAS THAT DO NOT MANAGE TO CLEAR
AS EARLY...HIGHS MAY NEED TO BE TWEAKED DOWNWARD A FEW DEGREES.
LENNING
&&
.SHORT TERM...
304 AM CDT
THROUGH FRIDAY...
COMPACT BUT STRONG VORT IS MOVING NORTHWARD ACROSS ILLINOIS THIS
MORNING AND DRIVING AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS
NORTHWARD ACROSS FAR EASTERN ILLINOIS AND WESTERN INDIANA EARLY THIS
MORNING. THIS ACTIVITY WILL AFFECT CHICAGO AREA AND NW INDY INTO THE
EARLY MORNING HOURS BEFORE MOVING OUT OF THE REGION. FAIRLY
EXTENSIVE CLOUD COVER UPSTREAM AND WITH RAIN LIKELY TO FURTHER
SATURATED THE COLUMN AM CONCERNED THAT CLOUD COVER COULD BE FAIRLY
PREVALENT ACROSS ESPECIALLY EASTERN PORTIONS OF THE CWA INTO AT
LEAST THE FIRST PART OF THE AFTERNOON WHICH SHOULD SLOW TEMPERATURE
RISE AND LIKELY KEEP TEMPS FROM GETTING ABOVE GUIDANCE TODAY UNLIKE
THE PAST COUPLE DAYS.
IN THE WAKE OF THIS MORNING`S SHORTWAVE LOOK FOR HEIGHT RISES AS
UPPER RIDGING BUILDS INTO THE REGION IN ADVANCE OF THE BIG WESTERN
CUT-OFF LOW. RISING HEIGHTS AND WARMING LOW/MID LEVEL LOOK TO SET
THE STAGE FOR A COUPLE OF RATHER TOASTY DAYS AWAY FROM THE
LAKEFRONT. PROGGED 925MB TEMPS INTO THE MID TEENS CELSIUS SUPPORT
HIGHS AROUND 80F AND HAVE BUMPED TEMPS IN THE GRIDS UPWARD TOWARD
THE DIRECTION...AND GIVEN THE RECENT COOL BIAS IN GUIDANCE ITS
POSSIBLE THAT THESE FORECAST GRIDS COULD END UP TOO COOL STILL WITH
80F+ ACROSS MOST OF THE CWA FRIDAY AND SATURDAY.
IZZI
&&
.LONG TERM...
304 AM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
GUIDANCE IS REMAINS IN RELATIVELY GOOD AGREEMENT ON THE EJECTION OF
THE BIG WESTERN CLOSED LOW WITH SHOWERS AND THUNDERSTORMS IN ADVANCE
OF THIS SYSTEM EXPECTED TO ARRIVE PROBABLY SUNDAY AND COULD STICK
AROUND AT TIMES INTO SUNDAY NIGHT. GFS REMAINS IS ON THE FASTER END
OF THE GUIDANCE ENVELOPE...BUT GIVEN THE TENDENCY FOR THESE SYSTEMS
TO BE SLOWER THAN PROGGED HAVE KEPT POPS BELOW GUIDANCE SAT NIGHT
MORE IN LINE WITH THE SLOWER GEM SOLUTION.
THE WESTERN CUT OFF LOW IS PROGGED TO PHASE WITH AMPLIFYING NORTHERN
STREAM LONG TROUGH THAT LOOKS TO STALL OUT OVER THE GREAT LAKES
REGION NEXT WEEK. THIS WILL RESULT IN AN END TO THE ABOVE AVERAGE
TEMPERATURES THAT HAVE DOMINATED MUCH OF THIS MONTH...BUT LOOKS TO
BE A FAIRLY DRY PATTERN THROUGH THURSDAY.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT AND VARIABLE WINDS FAVORING EAST AND NORTHEAST THROUGH THE
AFTERNOON.
MDB
//DISCUSSION...UPDATED 18Z...
MVFR LEVEL CLOUDS ARE QUICKLY ERODING LEAVING A VFR DECK OF AROUND
6000 FT. THIS DECK WILL MOVE DRIFT EAST AND PROBABLY ERODE A BIT
THROUGH THE AFTERNOON WITH SOME STRATO CU DEVELOPING ON THE
FRINGES...WHICH WOULD ALSO BE VFR. OTHERWISE LIGHT AND VARIABLE
WINDS WILL BE THE RULE THROUGH THE AFTERNOON AND EVEN THE REST OF
THE NIGHT. EXPECT THAT ORD/MDW WILL FAVOR AN EAST TO NORTHEAST
DIRECTION THANKS TO LAKE INFLUENCES BUT STILL SEE QUITE A BIT OF
VARIABILITY. GYY WOULD LIKELY BE NORTH TO NORTHEAST WITH
VARIABILITY. MANY AREAS WILL PROBABLY EVEN GO CALM AT TIMES. THERE
MAY BE SOME FOG THAT DEVELOPS TONIGHT BUT GIVEN THE DRY CONDITIONS
OF THE PAST FEW DAYS AND ONLY SOME SPOTTY SHOWERS/DRIZZLE THIS
MORNING THE POTENTIAL IS PRETTY LOW.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND FORECAST.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR. WX NIL. SOUTHEAST WINDS LESS THAN 10 KT.
SATURDAY...VFR...THEN SLIGHT CHANCE SHRA/MVFR AFTER MIDNIGHT. EAST
WINDS 10-15 KT.
SUNDAY...LIKELY SHRA/CHANCE TSRA. MVFR POSSIBLE. EAST WINDS 10-15
KT...BECMG NORTHWEST LESS THAN 10 KT OVERNIGHT.
MONDAY...CHANCE SHRA MONDAY...SLIGHT CHANCE SHRA OVERNIGHT. MVFR
POSSIBLE. WEST TO NORTHWEST WINDS 10-15 KT.
TUESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS 15-20KT
TUESDAY...DIMINISHING TO 5-10 KT OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS LESS THAN 10
KT.
KREIN
&&
.MARINE...
304 AM CDT
A RELATIVELY QUIET PERIOD OF WEATHER IS EXPECTED FOR LAKE MICHIGAN
FOR THE NEXT SEVERAL DAYS. HIGH PRESSURE CENTERED OVER SOUTHERN
QUEBEC WILL MOVE OFF THE NEW ENGLAND COAST TODAY...AS LOW PRESSURE
OVER NORTHERN ONTARIO MOVES ACROSS JAMES BAY. MEANWHILE...LOW
PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY DRIFT SOUTHEAST. WITH
A WEAK PRESSURE GRADIENT OVER THE LAKE...LIGHT WINDS WILL COVER
THE OPEN WATERS WHILE ONSHORE FLOW AND A LAKE BREEZE DEVELOP OVER
THE NEARSHORE WATERS TODAY. A SIMILARLY SETUP IS EXPECTED FOR
FRIDAY...BUT THEN A DEEPENING LOW WILL PASS TO THE NORTH OF LAKE
SUPERIOR FRIDAY EVENING WITH AN ASSOCIATED COLD FRONT PUSHING
SOUTH DOWN LAKE MICHIGAN FRIDAY NIGHT...ALLOWING FOR STRENGTHENING
NORTH TO NORTHEAST WINDS TO DEVELOP OVER THE LAKE FOLLOWING THE
FROPA...BUT DO NOT EXPECT WINDS TO EXCEED 20-25 KT. HIGH PRESSURE
WILL THEN BUILD SOUTHEAST ACROSS THE GREAT LAKES AND ONTARIO
FRIDAY NIGHT INTO SATURDAY.
&&
.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/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1126 AM CDT THU APR 16 2015
.UPDATE...
1113 AM CDT
TEMPERATURE AND PRECIPITATION TRENDS APPEAR TO BE ON TRACK LATE
THIS MORNING UNDER SIGNIFICANT CLOUD COVER WITH A FEW AREAS OF
PATCHY DRIZZLE MAINLY SOUTH OF THE LAKE. LIGHT WINDS UNDER THE
CLOUD DECK ARE NOT ASSISTING THE MIXING OUT OF LOW LEVEL
MOISTURE...BUT RAP RH TRENDS AND RECENT SATELLITE LOOPS SUGGEST
THE CLOUDS WILL BE SCATTERING OUT LATER THIS AFTERNOON WHICH
WOULD ALLOW TEMPERATURES TO CLIMB RAPIDLY AS SEEN ACROSS NORTHWEST
ILLINOIS AND EASTERN IOWA. FOR AREAS THAT DO NOT MANAGE TO CLEAR
AS EARLY...HIGHS MAY NEED TO BE TWEAKED DOWNWARD A FEW DEGREES.
LENNING
&&
.SHORT TERM...
304 AM CDT
THROUGH FRIDAY...
COMPACT BUT STRONG VORT IS MOVING NORTHWARD ACROSS ILLINOIS THIS
MORNING AND DRIVING AN AREA OF SHOWERS AND EMBEDDED THUNDERSTORMS
NORTHWARD ACROSS FAR EASTERN ILLINOIS AND WESTERN INDIANA EARLY THIS
MORNING. THIS ACTIVITY WILL AFFECT CHICAGO AREA AND NW INDY INTO THE
EARLY MORNING HOURS BEFORE MOVING OUT OF THE REGION. FAIRLY
EXTENSIVE CLOUD COVER UPSTREAM AND WITH RAIN LIKELY TO FURTHER
SATURATED THE COLUMN AM CONCERNED THAT CLOUD COVER COULD BE FAIRLY
PREVALENT ACROSS ESPECIALLY EASTERN PORTIONS OF THE CWA INTO AT
LEAST THE FIRST PART OF THE AFTERNOON WHICH SHOULD SLOW TEMPERATURE
RISE AND LIKELY KEEP TEMPS FROM GETTING ABOVE GUIDANCE TODAY UNLIKE
THE PAST COUPLE DAYS.
IN THE WAKE OF THIS MORNING`S SHORTWAVE LOOK FOR HEIGHT RISES AS
UPPER RIDGING BUILDS INTO THE REGION IN ADVANCE OF THE BIG WESTERN
CUT-OFF LOW. RISING HEIGHTS AND WARMING LOW/MID LEVEL LOOK TO SET
THE STAGE FOR A COUPLE OF RATHER TOASTY DAYS AWAY FROM THE
LAKEFRONT. PROGGED 925MB TEMPS INTO THE MID TEENS CELSIUS SUPPORT
HIGHS AROUND 80F AND HAVE BUMPED TEMPS IN THE GRIDS UPWARD TOWARD
THE DIRECTION...AND GIVEN THE RECENT COOL BIAS IN GUIDANCE ITS
POSSIBLE THAT THESE FORECAST GRIDS COULD END UP TOO COOL STILL WITH
80F+ ACROSS MOST OF THE CWA FRIDAY AND SATURDAY.
IZZI
&&
.LONG TERM...
304 AM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
GUIDANCE IS REMAINS IN RELATIVELY GOOD AGREEMENT ON THE EJECTION OF
THE BIG WESTERN CLOSED LOW WITH SHOWERS AND THUNDERSTORMS IN ADVANCE
OF THIS SYSTEM EXPECTED TO ARRIVE PROBABLY SUNDAY AND COULD STICK
AROUND AT TIMES INTO SUNDAY NIGHT. GFS REMAINS IS ON THE FASTER END
OF THE GUIDANCE ENVELOPE...BUT GIVEN THE TENDENCY FOR THESE SYSTEMS
TO BE SLOWER THAN PROGGED HAVE KEPT POPS BELOW GUIDANCE SAT NIGHT
MORE IN LINE WITH THE SLOWER GEM SOLUTION.
THE WESTERN CUT OFF LOW IS PROGGED TO PHASE WITH AMPLIFYING NORTHERN
STREAM LONG TROUGH THAT LOOKS TO STALL OUT OVER THE GREAT LAKES
REGION NEXT WEEK. THIS WILL RESULT IN AN END TO THE ABOVE AVERAGE
TEMPERATURES THAT HAVE DOMINATED MUCH OF THIS MONTH...BUT LOOKS TO
BE A FAIRLY DRY PATTERN THROUGH THURSDAY.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* LIGHT NORTHEAST WINDS WHICH WILL BE VARIABLE AT TIMES.
* MVFR CIGS IMPROVING TO VFR MID/LATE AFTERNOON.
MDB
//DISCUSSION...UPDATED 16Z...
IFR HAS IMPROVED TO MVFR EXCEPT FOR AREAS SOUTH OF THE TERMINALS.
AM STILL THINKING THAT ORD/MDW MAY SEE LOWERING OF CIGS TOWARDS
015 IN THE NEXT 1-2 HRS BEFORE LIFTING AND EVENTUALLY SCATTERING
OCCURS. WINDS HAVE DROPPED OFF AND THE DIRECTION HAS BECOME QUITE
VARIABLE ACROSS THE TERMINALS BUT EXPECT THE LAKE INFLUENCE TO
PROVIDE A SOMEWHAT STEADIER EAST TO NORTHEAST DIRECTION AT ORD/MDW
AND NORTH TO NORTHEAST DIRECTION AT GYY LATER THIS AFTERNOON. MAY
ALSO SEE A SLIGHT BUMP IN SPEEDS AS THIS OCCURS.
MDB
FROM 12Z...
A WEAK MID LEVEL CIRCULATION MOVING NWD ALONG THE IL/IN BORDER.
SCT SHOWERS ASSOCIATED WITH THE MID LEVEL CIRCULATION HAVE MOVED
INTO FAR NERN IL AND NWRN IN...MAINLY IMPACTING GYY/ORD/MDW. THE
POTENTIAL FOR ANY PCPN REACHING THE GROUND AT DPA IS DIMINISHING
AS THE MID LEVEL CIRCULATION SHOULD TAKE A TURN TO THE NORTHEAST
LATER THIS MORNING. WITH THE ARRIVAL OF SHOWERS OVER THE EASTERN
TERMINALS...FORECAST SOUNDINGS INDICATE A PERIOD OF MVFR...AND
POSSIBLY IFR CIGS THROUGH LATE THIS MORNING. LIGHT WINDS BY THAT
TIME SUGGEST MVFR CIGS MAY BE A LITTLE SLOW TO LIFT/SCATTER...AND
POSSIBLE MAY NOT IMPROVE TO VFR UNTIL THIS AFTERNOON.
THERE IS ALSO A CHANCE FOR SOME THUNDERSTORMS INVOF THE
CIRCULATION CENTER...BUT IT IS UNLIKELY THAT ANY THUNDER WILL
IMPACT THE TERMINALS...AND SHOULD REMAIN TO THE SOUTHEAST.
WITH A WEAK GRADIENT IN PLACE...WINDS ARE EXPECTED TO BECOME
NORTHEAST NEAR LAKE MICHIGAN...WHILE THE MORE INLAND SITES DPA
AND RFD ARE LIKELY SEE LIGHT NORTH-NORTHWEST WINDS THIS AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN IN MVFR CIGS PERSISTING THROUGH EARLY
AFTERNOON WITH MEDIUM CONFIDENCE IN TIMING OF SCATTERING.
* HIGH CONFIDENCE IN LIGHT WIND SPEEDS AND VARIABLE WIND
DIRECTION. MEDIUM-HIGH CONFIDENCE IT WILL FAVOR A NORTHEAST TO
EAST DIRECTION.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR. WX NIL. SOUTHEAST WINDS LESS THAN 10 KT.
SATURDAY...VFR...THEN SLIGHT CHANCE SHRA/MVFR AFTER MIDNIGHT. EAST
WINDS 10-15 KT.
SUNDAY...LIKELY SHRA/CHANCE TSRA. MVFR POSSIBLE. EAST WINDS 10-15
KT...BECMG NORTHWEST LESS THAN 10 KT OVERNIGHT.
MONDAY...CHANCE SHRA MONDAY...SLIGHT CHANCE SHRA OVERNIGHT. MVFR
POSSIBLE. WEST TO NORTHWEST WINDS 10-15 KT.
TUESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS 15-20KT
TUESDAY...DIMINISHING TO 5-10 KT OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SHRA...OTRW VFR. WEST WINDS LESS THAN 10
KT.
KREIN
&&
.MARINE...
304 AM CDT
A RELATIVELY QUIET PERIOD OF WEATHER IS EXPECTED FOR LAKE MICHIGAN
FOR THE NEXT SEVERAL DAYS. HIGH PRESSURE CENTERED OVER SOUTHERN
QUEBEC WILL MOVE OFF THE NEW ENGLAND COAST TODAY...AS LOW PRESSURE
OVER NORTHERN ONTARIO MOVES ACROSS JAMES BAY. MEANWHILE...LOW
PRESSURE OVER THE CENTRAL PLAINS WILL SLOWLY DRIFT SOUTHEAST. WITH
A WEAK PRESSURE GRADIENT OVER THE LAKE...LIGHT WINDS WILL COVER
THE OPEN WATERS WHILE ONSHORE FLOW AND A LAKE BREEZE DEVELOP OVER
THE NEARSHORE WATERS TODAY. A SIMILARLY SETUP IS EXPECTED FOR
FRIDAY...BUT THEN A DEEPENING LOW WILL PASS TO THE NORTH OF LAKE
SUPERIOR FRIDAY EVENING WITH AN ASSOCIATED COLD FRONT PUSHING
SOUTH DOWN LAKE MICHIGAN FRIDAY NIGHT...ALLOWING FOR STRENGTHENING
NORTH TO NORTHEAST WINDS TO DEVELOP OVER THE LAKE FOLLOWING THE
FROPA...BUT DO NOT EXPECT WINDS TO EXCEED 20-25 KT. HIGH PRESSURE
WILL THEN BUILD SOUTHEAST ACROSS THE GREAT LAKES AND ONTARIO
FRIDAY NIGHT INTO SATURDAY.
&&
.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/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1257 AM CDT THU APR 16 2015
.UPDATE...
758 PM CDT
HAVE ONLY MADE SLIGHT ADJUSTMENTS TO THE REST OF TONIGHT FORECAST.
A PICTURESQUE SKY OF VIRGA FROM CIRRUS/HIGH BASED ALTOCU OUT OUR
WINDOW AT SUNDOWN AND SHARED WITH US BY SEVERAL OF OUR SOCIAL
MEDIA FOLLOWERS. THE RAOB FROM DVN AT 00Z INDICATES A WARM
ADVECTION PROFILE FROM JUST OFF THE DECK ALL THE WAY UP...WITH
MOISTENING OCCURRING 15000 FT AND ABOVE ALONG WITH SOME MODEST
LAPSE RATES...THOUGH VERY DRY STILL BELOW THAT. AT ILX THIS
SATURATED LAYER IS DOWN TO 6000 FT WITH PRONOUNCED DRYING BELOW.
WATER VAPOR IMAGERY INDICATES A COMPACT BUT MOISTURE-STARVED
CIRCULATION IN SOUTHWEST ILLINOIS ADVANCING NORTHEAST...WITH SOME
SHOWER ACTIVITY REACHING THE GROUND AHEAD OF IT IN THE CENTRALIA
AND EFFINGHAM AREAS. TIMING THIS CORRIDOR OF FORCING WOULD MOVE
IT INTO THE SOUTHERN FORECAST AREA AROUND 11 PM. RAP AND NAM
FORECASTS INDICATE MOVE VEERED/SOUTHERLY PROFILES DOWN TO
900MB...WITH FORECAST MOISTURE TRANSPORT AND ADIABATIC LIFT
LIKELY TO AID IN SATURATION FOR AT LEAST SCATTERED LIGHT SHOWERS
ACROSS THE EASTERN FORECAST AREA. THAT IS IN LINE WITH GOING
FORECAST AND FOR THE MOST PART CURRENT HIGH-RES GUIDANCE. JUST
HAVE SLOWED THE START TIME OF POPS DOWN SLIGHTLY...BUT ALL IN ALL
A NEGLIGIBLE CHANGE TO WORDING FOR MOST AREAS. RAINFALL AMOUNTS
UNDER 0.15 OF AN INCH LOOK GOOD...WITH MOST OF NORTH CENTRAL
ILLINOIS NOT SEEING MORE THAN A TRACE.
GOING TEMPERATURES AND IMPROVING RELATIVE HUMIDITY VALUES LOOK ON
TRACK.
MTF
&&
.SHORT TERM...
339 PM CDT
THROUGH FRIDAY...
BETTER AGREEMENT BETWEEN DETERMINISTIC MODELS AND THEIR ENSEMBLE
COUNTERPARTS IS PROVIDING INCREASED FORECAST CONFIDENCE FOR THE
REMAINDER OF THE WEEK AND INTO EARLY NEXT WEEK. THE PRIMARY UPPER
LEVEL FEATURES BEING TRACKED INCLUDE A LARGE SOUTHERN STREAM LOW
DIGGING INTO THE FOUR CORNERS...A DOWNSTREAM RIDGE WITH EMBEDDED
SHORTWAVES...AND A CLOSED LOW PROJECTED TO DEVELOP IN A DEEPENING
NORTHERN STREAM TROUGH AND MERGE LATE IN THE WEEKEND WITH THE SYSTEM
THAT FINALLY WILL BE LIFTING OUT OF THE DESERT SOUTHWEST. AT LOWER
LEVELS...MODELS AGREE IN LIFTING A WEAK SURFACE TROUGH ACROSS THE
AREA TONIGHT AND IN TAKING A MORE DEVELOPED LOW PRESSURE SYSTEM
ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY IN CONJUNCTION WITH THE
MERGING UPPER TROUGHS.
FOR THIS EVENING AND OVERNIGHT...THE AREA OF SHOWERS AND ISOLATED
TSRA STRETCHING FROM NORTHWEST IA ACROSS MO AND INTO KY IS
CORRELATED WITH A GRADIENT OF ENHANCED MOISTURE FLUX DEPICTED IN THE
RAP. AS THIS GRADIENT LIFTS NORTH...PRECIP CHANCES INCREASE TOWARD
MIDNIGHT AND ESPECIALLY IN THE PREDAWN HOURS. FORECAST SOUNDINGS
TREND TOWARD MOIST ADIABATIC AND DEEPLY SATURATED...SO PWATS
INCREASE CONSIDERABLY OVERNIGHT BUT INSTABILITY IS TALL AND SKINNY.
BETTER CHANCE OF TSRA WILL LIKELY REMAIN SOUTH AND EAST OF THE METRO
AREA.
DURING THE DAYTIME THURSDAY AND ESPECIALLY INTO THURSDAY
NIGHT...HEIGHTS INCREASE ALOFT AS THE UPPER SHORTWAVES MOVE EAST OF
THE AREA AND LOWER LEVELS DRY OUT. WILL CARRY LOW CHANCE POPS INTO
THE THURSDAY MORNING HOURS AND EARLY AFTERNOON BUT KEEP THURSDAY
NIGHT AND FRIDAY DRY.
LENNING
&&
.LONG TERM...
339 PM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
AFTER ANOTHER QUIET DAY ON SATURDAY...THE MERGING NORTHERN AND
SOUTHERN STREAM TROUGHS AND DEVELOPMENT OF A CLOSED SURFACE LOW IN
THE LEE OF THE ROCKIES WILL BRING INCREASED PRECIP CHANCES TO THE
AREA FOR SATURDAY NIGHT AND SUNDAY. WITH THE CENTER OF THE SURFACE
LOW PASSING SOUTH OF THE AREA ACROSS CENTRAL ILLINOIS...AM SEEING
GOOD SUPPORT FOR SHOWERS SATURDAY NIGHT AND EARLY SUNDAY BUT NOT
MUCH IN THE WAY OF CONVECTION UNTIL THE LOW PUSHES A WARM FRONT
THROUGH THE AREA AROUND MIDDAY AND BRIEFLY MOVES THE AREA INTO
THE WARM SECTOR AHEAD OF THE TRAILING COLD FRONT. THE PEAK PERIOD
FOR TSRA WOULD APPEAR TO BE SUNDAY AFTERNOON AND EVENING.
AFTER THE SURFACE LOW LIFTS WELL NORTH OF THE AREA SUNDAY NIGHT
INTO MONDAY...CYCLONIC FLOW ALOFT AND RESIDUAL BOUNDARY LAYER
MOISTURE MAY CONTINUE TO SUPPORT THE CHANCE OF SHOWERS INTO
MONDAY...BUT A RIDGE OF HIGH PRESSURE WILL BEGIN TO BUILD FROM THE
PLAINS INTO THE SOUTHERN GREAT LAKES BY TUESDAY...AGAIN DRYING
THINGS OUT FOR AT LEAST THE FIRST HALF OF THE WEEK.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* EAST WINDS ARND 10 KT OVERNIGHT.
* POTENTIAL FOR SHOWERS TONIGHT/EARLY THURSDAY MORNING.
* A PERIOD OF MVFR/IFR LIKELY EARLY THURSDAY.
* NORTHEAST WINDS 10 KT OR LESS THURSDAY.
KREIN
//DISCUSSION...UPDATED 06Z...
THE EAST LOW LEVEL FLOW WAS MAINTAINING ADVECTION OF DRY LOW
LEVEL AIR ACROSS MUCH OF NORTHERN ILLINOIS...WHILE SOUTH-
SOUTHEAST WINDS ALOFT WERE PULLING MOISTURE NORTHWARD ALOFT OVER
NORTHWESTERN INDIANA AS A WEAK MID LEVEL CIRCULATION MOVES NWD
ALONG THE IL/IN BORDER. SCT SHOWERS ASSOCIATED WITH THE MID LEVEL
CIRCULATION ARE SLOWLY MOVING NWD INTO NWRN IN...BUT ARE HAVING
SOME TROUBLE OVERCOMING THE DRY LOW LEVEL AIR...SO IT WILL STILL
TAKE SOME TIME FOR RAIN TO REACH THE SURFACE. STILL FEEL THAT
THERE IS SOME POTENTIAL FOR SHRA AT THE CHICAGO AREA
TERMINALS...ESPECIALLY GYY AND MDW...BUT ORD/DPA STILL HAVE SOME
POTENTIAL AS WELL. WILL MAINTAIN THE VCSH AT RFD...THOUGH THE
POTENTIAL FOR ANY PCPN REACHING THE GROUND THERE IS DIMINISHING AS
THE MID LEVEL CIRCULATION SHOULD TAKE A TURN TO THE NORTHEAST
LATE TONIGHT. WITH THE ARRIVAL OF SHOWERS OVER THE EASTERN
TERMINALS...FORECAST SOUNDINGS INDICATE A PERIOD OF MVFR... AND
POSSIBLY IFR CIGS EARLY THURSDAY MORNING. LIGHT WINDS BY THAT
TIME SUGGEST MVFR CIGS MAY BE A LITTLE SLOW TO LIFT/SCATTER...AND
MAY NOT IMPROVE TO VFR UNTIL THURSDAY AFTERNOON.
WEAK GRADIENT AND LIGHT WINDS THURSDAY ARE EXPECTED TO BECOME
NORTHEAST NEAR LAKE MICHIGAN...WHILE INLAND SITES DPA AND RFD ARE
LIKELY SEE LIGHT NORTH-NORTHWEST WINDS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN SHRA COVERAGE/TIMING OVERNIGHT AND EARLY
THURSDAY.
* MEDIUM-HIGH CONFIDENCE IN PERIOD OF MVFR CIGS...MEDIUM IN IFR.
* LOW-MEDIUM CONFIDENCE IN TRENDS THURSDAY.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...VFR. LIGHT VARIABLE WINDS BECOMING SOUTHEAST.
SATURDAY...VFR. CHANCE OF SHRA WITH MVFR POSSIBLE SATURDAY NIGHT.
NORTHEAST WINDS.
SUNDAY...CHANCE SHRA. MVFR POSSIBLE. EAST-NORTHEAST WINDS.
MONDAY...CHANCE SHRA EARLY. MVFR IMPROVING TO VFR. WEST-NORTHWEST
WINDS.
TUESDAY...VFR. CHANCE SHRA TUES NGT. WEST WINDS.
RATZER
&&
.MARINE...
153 PM CDT
A RIDGE OF HIGH PRESSURE CENTERED JUST TO THE NORTHEAST OF THE
GREAT LAKES IS ALLOWING FOR LIGHTER WINDS ACROSS THE LAKE
TODAY...BUT WITH THE HIGHEST WINDS OF 10 TO 20 KT BEING OBSERVED
OVER THE SOUTHERN HALF. EASTERLY WINDS OF 10 TO 20 KT WILL
CONTINUE TONIGHT FOR THE SOUTH HALF AND THE NEARSHORE AS A TIGHTER
PRESSURE GRADIENT REMAINS...AND WITH MORE STABLE CONDITIONS
HELPING TO KEEP WIND SPEEDS DOWN. SURFACE PATTERN BEGINS TO RELAX
LATER TONIGHT INTO THURSDAY MORNING WHILE SPEEDS DIMINISH AND WITH
WINDS LIKELY BECOMING VARIABLE DURING THE DAY THURSDAY. THIS
RELAXED PATTERN LOOKS TO PERSIST THROUGH THE END OF THE WORK
WEEK...WITH GENERALLY LIGHTER SPEEDS IN PLACE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
635 PM CDT FRI APR 17 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 323 PM CDT FRI APR 17 2015
THE SHORT TERM FOCUS IS ON CONVECTION BOTH DURING THE AFTERNOON AND
AGAIN LATER TONIGHT. A RELATIVELY WEAK TO MODERATE BOUYANCY/CAPE BUT
HIGH SHEAR ENVIRONMENT IS SET UP FOR THIS AFTERNOON WITH A
STATIONARY BOUNDARY SEPARATING A MOIST A COOLER AIRMASS ACROSS
NORTHERN KANSAS AND DRYER WARMER AIR BEHIND A DRYLINE WEST OF
LIBERAL. THE CONVECTIVE ALLOWING MODELS SUPPORT DISCREET
THUNDERSTORM DEVELOPMENT IN THE UPSLOPE CONVERGENCE REGION WITH
GENERALLY NORTHWARD RIGHT MOVING STORM MOTIONS. THIS WILL PRESENT
A TORNADO RISK ACROSS OUR NORTHWEST COUNTIES ESPECIALLY THE AREA
NORTHWEST OF THE GARDEN CITY TO SYRACUSE, DIGHTON AND SCOTT CITY.
ADDITIONAL STORMS ARE LIKELY TO FORM FARTHER SOUTH AHEAD OF THE
DRYLINE AND MOVE NORTHEAST THROUGH THE REST OF THE AREA, WITH STILL
A THREAT OF HAIL AND WIND. A PERIOD OF SEVERE RISK THROUGH THE MID
EVENING WILL FOLLOW AS FORCING FROM THE UPPER JET PROMOTES LIFT
THROUGH THE REST OF OUR CENTRAL KANSAS COUNTIES.
AS THE UPPER LOW OVERSPREADS THE AREA INTO SATURDAY MORNING, THE
WARM/MOIST CONVEYOR BELT REGIONS WILL BE MOST LIKELY ACROSS THE
NORTHERN AND EASTERN SECTIONS OF THE FORECAST AREA, BY CONSENSUS OF
THE MODELS. HERE AN ADDITIONAL QUARTER TO LESS THAN AN INCH OF RAIN
MAY OCCUR TROUGH SATURDAY MORNING. ADDITIONAL SEVERE STORMS ARE
POSSIBLE SATURDAY UNDER THE UPPER COLD POOL AND VORTICITY MAXIMUM
THAT BE MOVING INTO WESTERN KS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 120 PM CDT FRI APR 17 2015
THE VERY SLOW MOVING UPPER LOW WILL CONTINUE TO PROVIDE CHANCES FOR
PRECIPITATION UNTIL IT FINALLY CLEARS THE REGION...WHICH WILL NOT BE
UNTIL SOMETIME SUNDAY. WE WILL BE KEEPING SOME CHANCE POPS
ALONG/NORTH OF THE ARKANSAS RIVER AS THE 500-700MB DEFORMATION AXIS
PIVOTS EASTWARD ACROSS WEST-CENTRAL KANSAS FROM LATE SATURDAY NIGHT
THROUGH ABOUT MIDDAY SUNDAY. STRONG NORTH-NORTHWEST WINDS WILL
FOLLOW ON SUNDAY AND AN OVERALL COOL, DAMP, WINDY DAY APPEARS QUITE
LIKELY FOR MUCH OF THE DAY. WE WILL SEE SOME SCATTERING OUT OF
CLOUDS BY LATE IN THE DAY SUNDAY FROM NORTHWEST TO SOUTHEAST, BUT IT
WILL NOT LAST LONG AS ANOTHER MINOR SHORTWAVE TROUGH WILL BE
SWINGING SOUTHEAST FROM THE NORTHERN ROCKIES AROUND A DEEPENING
UPPER MIDWEST/GREAT LAKES LONGWAVE GYRE. THIS WILL ONLY ACT TO KEEP
COOL TEMPERATURES AROUND MONDAY WITH A SLIGHT CHANCE FOR SOME LIGHT
RAIN IN A WEAK NORTHWEST FLOW DEFORMATION AXIS. BY MID-WEEK, WE WILL
SEE SOME WEAK RIDGING APPROACH THE HIGH PLAINS WITH WESTERN KANSAS
IN THE MIDDLE OF A SPLIT-FLOW PATTERN. ACROSS THE WESTERN CONUS, THE
CONTINUED AMPLIFICATION OF THE NORTHERN BRANCH WILL LEAD TO A MERGER
OF NORTHERN BRANCH ENERGY WITH THE SOUTHERN BRANCH JET ACROSS THE
DESERT SOUTHWEST REGION. MEANWHILE, THE AFOREMENTIONED GREAT LAKES
LONGWAVE LOW WILL CONTINUE TO HAVE AN INFLUENCE WITH A COLD AIRMASS
(FOR MID/LATE APRIL) LOCKED IN PLACE ACROSS THE NORTHERN PLAINS INTO
THE MIDWEST REGION. A FAIRLY ROBUST LOWER TROPOSPHERIC BAROCLINIC
ZONE WILL BECOME ESTABLISHED ACROSS THE CENTRAL PLAINS. THIS APPEARS
TO BE A SETUP FAVORABLE FOR ORGANIZED (A) PRECIPITATION EVENT(S)
AFFECTING SOUTHWEST KANSAS LATE IN THE UPCOMING WEEK. IT IS UNCLEAR
HOW THIS WILL ALL UNFOLD AT DAYS 7-10 IN THE FORECAST, BUT THE
LONGWAVE PATTERN CERTAINLY APPEARS FAVORABLE FOR A WETTER THAN
AVERAGE 3-5 DAY PERIOD FOR MID TO LATE APRIL. THE OFFICIAL FORECAST
WILL CONTINUE TO REFLECT 20-40 POPS FOR EACH PERIOD MID-LATE NEXT
WEEK AS THIS WET PATTERN TAKES SHAPE ACROSS THE CENTRAL/SOUTHERN
PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 633 PM CDT FRI APR 17 2015
LOW LEVEL MOISTURE INCREASES ACROSS WESTERN KANSAS OVERNIGHT AS A
SOUTHEASTERLY FLOW CONTINUES. RAP AND HRR WERE BOTH IN DECENT
AGREEMENT WITH MVRF CEILINGS DEVELOPING DEVELOPING TOWARDS 06Z,
ESPECIALLY AT DDC. AREAS OF FOG WILL ALSO BE POSSIBLE IN THE DDC
AND GCK AREA TOWARDS DAYBREAK AS CEILINGS LOWER INTO THE IFR
CATEGORY AT TIMES. ON GOING CONVECTION WILL CONTINUE THROUGH EARLY
TONIGHT NEAR AND NORTH OF A GCK TO DDC LINE. PRECIPITATION CHANCES
ARE EXPECTED TO BRIEFLY INCREASE IN AREAL COVERAGE BETWEEN SUNSET
AND 6Z SATURDAY AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE
WEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 72 46 64 / 30 30 30 30
GCK 48 69 45 61 / 40 30 20 20
EHA 42 68 44 62 / 10 20 20 10
LBL 46 71 46 63 / 20 20 20 10
HYS 56 72 49 61 / 70 50 50 60
P28 56 75 51 66 / 80 50 60 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ084.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
630 PM CDT Fri Apr 17 2015
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Saturday)
Issued at 346 PM CDT FRI APR 17 2015
Upper low continues to spin over the Rockies this afternoon with an
upper level jet rounding the base of the upper low and moving over
New Mexico. Earlier showers and thunderstorms were moving out of the
northern counties at 20Z. Some clearing was occurring across the
southern and western sections of the cwa this afternoon. Latest meso
analysis shows surface based CAPE around 500 to 1000 J/kg with an
uncapped atmosphere. Expect scattered convection to develop in
southwest Kansas along the dry line. additional scattered storms may
develop in south west and south central Kansas per the latest runs
of the RAP and HRRR. Models suggest additional development this
evening across western and central Kansas moving northeast into
north central Kansas with the increase and veering of the low level
jet overnight. Models are in agreement with a lobe of energy working
it`s way northeast out of Oklahoma later tonight and Saturday
morning. May see a repeat of this morning with an area of showers
and embedded thunderstorms moving across the area. Expect a break
for a few hours in the afternoon, then chances increase again with
storms developing again in the afternoon in western and central
Kansas as upward vertical motion increases with the advance of the
upper trough into the High Plains. Dryline looks to set up across
western Kansas with the GFS the furthest east in central Kansas.
Shear and instability will be favorable for some of the storms to be
strong to severe with large hail and winds the main hazards in the
late afternoon hours mainly west of a Herington to Washington
line.
.LONG TERM...(Saturday Night through Friday)
Issued at 346 PM CDT FRI APR 17 2015
Short range models are relatively consistent in moving surface low
and main piece of upper trough through eastern KS late Saturday
night and Sunday. Ahead of this system Saturday night, increasing
thunderstorm chances are expected, with some potential for severe
weather, with the best chance in our forecast area over the western
2/3. Shear parameters are not very impressive and amount of
sunshine and associated surface heating Sat afternoon and evening is
also a little suspect so this is not a high probability thing.
As the low and front move through on Sunday, some isolated thunder
may continue in the east in the morning, but showers associated with
cold air aloft just behind the front will continue precip chances
into the afternoon hours.
After that, subsidence and cold advection behind that system brings
in dry conditions and cooler temperatures for Sunday night through
Tuesday, with lows dipping into the upper 30s many places and highs
in the low to mid 60s.
Precip chances return to parts of eastern KS on Wednesday when weak
low-level warm advection and a weak wave in northwest flow aloft
interact. Latest ECMWF and GEM would indicate that the cool air at
the surface is more entrenched in place than the GFS, thus have
gone cooler than guidance for highs on Wednesday.
Beyond Wednesday, considerable differences exist between 12Z GFS and
ECMWF in upper flow pattern and precip chances. GFS and GFSEnsemble
places us in a more favorable pattern for a couple days of precip
for Thursday and Friday, while the ECMWF is slower in bringing a
shortwave trough out of the southwest U.S., and would give us the
better chances on Friday. Have gone with a general compromise
with 25 to 40 percent POPs for those days.
&&
.AVIATION...(For the 00Z TAFs through 00Z Saturday Evening)
Issued at 625 PM CDT FRI APR 17 2015
VFR prevails through at least the first 6 hours of the forecast
period. Activity forming across western and southern Kansas is
expected to impact sites after 06Z. Forecast soundings denote
mostly showers with a few thunderstorms. After 09Z, coverage
increases across the area with rain saturating conditions to MVFR
through Saturday morning. Showers exit eastward as uncertainty
increases for the afternoon in timing of next round for thunderstorms.
Have a VCTS mention with improvement to VFR for the time being.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...53
LONG TERM...GDP
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
121 PM CDT THU APR 16 2015
...UPDATED SHORT TERM SECTION...
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 120 PM CDT THU APR 16 2015
IN THE SHORT TERM, A FEW (2-3) ROUNDS OF CONVECTION ARE ANTICIPATED
THROUGH HE NEXT 24 TO 36 HOURS OR SO AS A LARGE UPPER LOW MOVES
TOWARD THE REGION WITH FORCING FOR ASCENT, AND PERSISTENT MID LEVEL
MOISTURE ADVECTION TO MAINTAIN INSTABILITY FOR A PROLONGED PERIOD.
THE FIRST ROUNDS ARE EXPECTED ALREADY EARLY THIS AFTERNOON AS THE
NESTED 4 KM NAM AND HRRR MODELS HAVE GENERALLY AGREED ON CONVECTIVE
INITIATION BETWEEN AROUND 2 AND 4 PM, AND RAPIDLY DEVELOPING INTO A
MULTICELLULAR LINE AFTER AN HOUR OR SO OF SLOWER GROWING DISCREET
CELLS. THE INITIAL ROTATING STORMS GENERALLY WEST OF HIGHWAY 83
SHOULD BE CAPABLE OF PRODUCING HAIL LARGER THAN GOLFBALLS AND
DAMAGING WIND BEFORE THE STORMS BECOME MORE CLUSTERED OR LINEAR,
PRESENTING A SLIGHTLY SMALLER HAIL THREAT AND STILL DAMAGING WIND
THREAT THROUGH THE HIGHWAY 283 AND 183 CORRIDORS INTO THE EARLY
EVENING HOURS. THESE MODEL SOLUTIONS COULD BE INTERFERED WITH BY THE
EXTENSIVE STRATUS ACROSS THE AREA REDUCING THE SEVERE THREAT.
ANOTHER ROUND OF THUNDERSTORMS WILL PROBABLY OCCUR LATE TONIGHT INTO
THE OVERNIGHT AND POSSIBLY STILL ONGOING EARLY FRIDAY MORNING, WITH
A CONTINUED HAIL IF NOT AN ISOLATED WIND THREAT AS WELL, ALTHOUGH
SOME BL STABILITY SHOULD HINDER THE WIND THREAT. THE DYNAMICS OF THE
UPPER LOW WILL DRIVE A DRY SLOT THROUGH THE REGION OF FRIDAY, BUT
NOT BEFORE LATE MORNING/EARLY AFTERNOON DESTABILIZATION CONTRIBUTES
TO YET ANOTHER SEVERE EPISODE WITH AS GOOD OR BETTER CAPE AND SHEAR
COMBINATIONS.
TEMPERATURES WERE RAISED FOR FRIDAY MORNING, FOLLOWING THE NAM AND
GFS, AS OVERNIGHT CONVECTION SHOULD LIMIT THE RADIATIONAL COOLING.
ADDITIONALLY THE POPS WERE RAISED LOWERED FRIDAY MORNING AND
INCREASED ALONG THE MOISTURE TRANSPORT AXIS INTO FRIDAY AFTERNOON
WITH A MODEL CONSENSUS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 1152 AM CDT THU APR 16 2015
FRIDAY NIGHT INTO SATURDAY WE WILL STILL BE DEALING WITH THE SLOW-
MOVING UPPER LOW, BUT BY THIS TIME THE LOW WILL BE SEVERELY OCCLUDED
WITH THE DRY INTRUSION WORKING IN FAST FROM THE SOUTHWEST. IN FACT,
FRIDAY NIGHT LOOKS RATHER DRY NOW WITH THE SYNOPTIC DRY INTRUSION
ACROSS MUCH OF KANSAS. WE HAVE REDUCED POPS AS A RESULT FRIDAY
NIGHT. AS WE HEAD INTO SATURDAY, ANY DAYTIME HEATING WILL PROMOTE
SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT AS THE CORE OF THE MID
LEVEL CYCLONE WALLOWS SLOWLY EASTWARD INTO FAR WESTERN KANSAS. WE
WILL MAINTAIN THE 20-40 POPS ACROSS MAINLY THE NORTHERN AND EASTERN
ZONES WITH A DRY FORECAST ACROSS FAR SOUTHWEST KANSAS.
WHAT IS LEFT OF THE LOW WILL FINALLY PULL AWAY SATURDAY NIGHT INTO
EARLY SUNDAY WITH FAIRLY STRONG NORTH WINDS TO FOLLOW DURING THE DAY
SUNDAY. WE COULD STILL SEE SOME WRAP-AROUND LIGHT PRECIPITATION IN
THE WEAKENING MID LEVEL DEFORMATION AXIS, HENCE THE 20 TOP 30 POPS
FOR MUCH OF THE AREA. LOOKING BEYOND THE WEEKEND, WE WILL ENTER A
NORTHWEST FLOW PATTERN ON THE SOUTHWEST SIDE OF A LARGE-SCALE UPPER
TROUGH ACROSS THE GREAT LAKES REGION. THE ATMOSPHERE WILL BE FAIRLY
COOL EARLY NEXT WEEK AS A RESULT WITH LARGE SCALE HIGH PRESSURE AT
THE SURFACE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 112 PM CDT THU APR 16 2015
SEVERE STORMS ARE EXPECTED LATER THIS AFTERNOON AND EARLY EVENING,
AND WILL BE ACCOUNTED FOR IN LOCAL TERMINALS. THE CONVECTION IS
MODELED BY THE CONVECTIVE ALLOWING MODELS TO GO FAIRLY
MULTICELLULAR, OR A BROKEN LINE WITH BOTH HAIL AND WIND THREAT EARLY
INTO THE EVENING, BUT BEGINNING AS ISOLATED TO SCATTERED AS EARLY AS
20-22 UTC.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 54 70 49 69 / 70 60 60 50
GCK 52 68 44 69 / 60 60 60 40
EHA 51 67 42 66 / 60 30 30 30
LBL 54 70 46 69 / 60 50 40 30
HYS 53 69 49 71 / 80 70 60 50
P28 56 71 54 72 / 70 60 60 50
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS JACKSON KY
616 PM EDT THU APR 16 2015
.UPDATE...
ISSUED AT 615 PM EDT THU APR 16 2015
UPDATED POPS FROM FRIDAY INTO SATURDAY. LATEST MODEL RUNS SUGGEST
THE TIME FRAME FROM LATE FRIDAY THROUGH SATURDAY WILL LIKELY BE
DRY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 306 PM EDT THU APR 16 2015
WITH THE LATEST RUN OF THE HRRR MODEL BEING A BIT OFF WITH ITS
HANDLING OF TODAYS CONVECTION...THE NAM12 WAS MODEL OF CHOICE FOR
THE SHORT TERM PORTION OF THE FORECAST. SHOWERS AND STORMS THAT
HAVE BEEN MOVING ACROSS EASTERN KENTUCKY THROUGHOUT THE DAY ARE
CURRENTLY AFFECTING THE NORTHEASTERN PORTION OF THE THE AREA. THIS
ACTIVITY IS EXPECTED TO MOVE ON OUT OF THE AREA IN THE NEXT FEW
HOURS. CURRENT RADAR INDICATES THAT ISOLATED TO SCATTERED SHOWERS
AND STORMS WILL CONTINUE TO MOVE INTO THE AREA FROM THE SOUTHWEST
DURING THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ONLY
ISOLATED ACTIVITY...IF THAT...WILL BE LEFT OVER FOR THE OVERNIGHT
HOURS. SHOWERS AND STORMS WILL BE POSSIBLE DURING THE DAY ON
FRIDAY...AS A WEAK FRONTAL BOUNDARY MOVES IN FROM THE WEST. WEAK
DISTURBANCES AHEAD OF THIS FRONT MAY ALSO KICK OFF SHOWERS AND
STORMS...BUT WITH A LACK OF INSTABILITY AND STRONG LIFT...IT
APPEARS THAT THE COVERAGE OF PRECIPITATION WILL BE SPARSE. BASED
ON THE LATEST MODEL DATA...THERE SHOULD BE LULL IN THE ACTION FROM
LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING...AS A WEAK
RIDGE OF HIGH PRESSURE BRIEFLY SETTLES OVER THE AREA.
TEMPERATURES DURING THE PERIOD WILL BE WELL ABOVE NORMAL FOR THIS
TIME OF YEAR...WITH HIGHS ON FRIDAY MAXING OUT IN THE 70S...AND
OVERNIGHT LOWS TONIGHT AND FRIDAY NIGHT BOTTOMING OUT IN THE LOW
TO MID 50S AREA WIDE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 PM EDT THU APR 16 2015
MAIN CONCERN DURING THE EXTENDED PERIOD IS FOCUSED ON A CUT OFF LOW
CURRENTLY OVER THE FOUR CORNERS REGION. THIS LOW IS PROGGED TO
PUSH SLOWLY EWD EARLY SATURDAY BEFORE ITS ENERGY GETS INGESTED AND
HELPS DEEPEN A NORTHERN STREAM TROUGH. THIS TROUGH WILL MOVE ALONG
THE US/CANADIAN BORDER UNTIL THE CLOSED LOW ENERGY PHASES WITH IT
AND MOVES EAST. IN ADDITION TO THE UPPER LEVEL TROUGH...A SFC LOW
IS FORECASTED TO DEVELOP SATURDAY NIGHT OVER THE PLAINS AND AHEAD
OF IT...A STRONG SURGE OF GULF MOISTURE RETURNS TO THE OH AND TN
VALLEYS. PW VALUES UP TO 1.4 INCHES ARE EXPECTED WITH THIS NEW
SURGE OF MOISTURE....WHICH ARE WELL ABOVE AVERAGE. THERE WILL BE
SOME MODERATE INSTABILITY AS WELL. THIS SYSTEM SHOULD PUSH OUT OF
KY BY MONDAY NIGHT. ON TUESDAY...A LOW THAT IS NOW CUT OFF IN THE
NORTHERN STREAM WILL UNDULATE OVER THE GREAT LAKES REGION THROUGH
THURSDAY WITH PIECES OF ENERGY WRAPPING AROUND IT. HOWEVER...THIS
SHOULDN/T CAUSE ANY ISSUES FOR KENTUCKY AS THE ENERGY APPEARS TO
STAY FURTHER NORTH UNTIL THURSDAY WHEN THE LOW STARTS SAGGING
SOUTHEASTWARD.
AT THE SFC...SATURDAY WILL BE MAINLY DRY AND WARM UNTIL LATE
AFTERNOON WHEN CHANCES FOR PRECIP BEGIN INCREASING. THE BULK OF
THE RAINFALL WILL FALL SUNDAY INTO MONDAY WHERE AT LEAST AN INCH
OF LIQUID IS LIKELY ACROSS EASTERN KENTUCKY. THERE IS ALSO A
CHANCE FOR THUNDERSTORMS DURING THIS TIME GIVEN THE MOIST AIR MASS
IN PLACE AND PLENTY OF SFC/UPPER LEVEL DYNAMICS. AS THIS SYSTEM
EXITS THE AREA MONDAY NIGHT...THINGS WILL DRY OUT AND EASTERN
KENTUCKY WILL GET A REPRIEVE FROM PRECIPITATION TUESDAY AND
WEDNESDAY. TEMPERATURES DURING THIS TIME WILL BE A BIT BELOW
NORMAL IF NOT RIGHT AT SEASONABLE LEVELS. RAIN CHANCES RETURN ON
THURSDAY AS THE LOW SAGS SOUTHEASTWARD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM EDT THU APR 16 2015
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
ACROSS EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS. THE OVERALL
TREND OVER THE PAST COUPLE OF HOURS HAS BEEN FOR THE ACTIVITY TO
WEAKEN AND DECREASE IN COVERAGE. THAT BEING SAID...IT LOOKS THERE
WILL BE A MUCH SMALLER CHANCE OF SHOWERS AND STORMS DIRECTLY
AFFECTING ANY OF THE TAF SITES THAN BEFORE. WHERE RAIN DOES
OCCUR...PARTICULARLY WITH THUNDERSTORMS...A TAF SITE MAY
EXPERIENCE BRIEF PERIODS OF MVFR CONDITIONS DURING THE MORE
INTENSE RAIN SHOWERS. THE SHOWERS AND STORMS SHOULD BE MOSTLY OUT
OF THE ARE BY AROUND 2Z THIS EVENING. THERE WILL BE A CHANCE OF
LINGERING SHOWERS AND STORMS OVERNIGHT...AS AN AREA OF DISTURBED
WEATHER PASSES BY THE AREA. ANOTHER BATCH OF ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS IS ON TAP FOR TOMORROW...AS YET ANOTHER
DISTURBANCE MOVES ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS.
THERE SHOULD BE A GOOD LULL IN THE RAIN BETWEEN ROUGHLY 2 AND
12Z...WITH A SLIGHT UPTICK IN THE ACTIVITY AT 12 OR 13Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...AR
LONG TERM...JVM
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
340 PM EDT THU APR 16 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 306 PM EDT THU APR 16 2015
WITH THE LATEST RUN OF THE HRRR MODEL BEING A BIT OFF WITH ITS
HANDLING OF TODAYS CONVECTION...THE NAM12 WAS MODEL OF CHOICE FOR
THE SHORT TERM PORTION OF THE FORECAST. SHOWERS AND STORMS THAT
HAVE BEEN MOVING ACROSS EASTERN KENTUCKY THROUGHOUT THE DAY ARE
CURRENTLY AFFECTING THE NORTHEASTERN PORTION OF THE THE AREA. THIS
ACTIVITY IS EXPECTED TO MOVE ON OUT OF THE AREA IN THE NEXT FEW
HOURS. CURRENT RADAR INDICATES THAT ISOLATED TO SCATTERED SHOWERS
AND STORMS WILL CONTINUE TO MOVE INTO THE AREA FROM THE SOUTHWEST
DURING THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ONLY
ISOLATED ACTIVITY...IF THAT...WILL BE LEFT OVER FOR THE OVERNIGHT
HOURS. SHOWERS AND STORMS WILL BE POSSIBLE DURING THE DAY ON
FRIDAY...AS A WEAK FRONTAL BOUNDARY MOVES IN FROM THE WEST. WEAK
DISTURBANCES AHEAD OF THIS FRONT MAY ALSO KICK OFF SHOWERS AND
STORMS...BUT WITH A LACK OF INSTABILITY AND STRONG LIFT...IT
APPEARS THAT THE COVERAGE OF PRECIPITATION WILL BE SPARSE. BASED
ON THE LATEST MODEL DATA...THERE SHOULD BE LULL IN THE ACTION FROM
LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING...AS A WEAK
RIDGE OF HIGH PRESSURE BRIEFLY SETTLES OVER THE AREA.
TEMPERATURES DURING THE PERIOD WILL BE WELL ABOVE NORMAL FOR THIS
TIME OF YEAR...WITH HIGHS ON FRIDAY MAXING OUT IN THE 70S...AND
OVERNIGHT LOWS TONIGHT AND FRIDAY NIGHT BOTTOMING OUT IN THE LOW
TO MID 50S AREA WIDE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 PM EDT THU APR 16 2015
MAIN CONCERN DURING THE EXTENDED PERIOD IS FOCUSED ON A CUT OFF LOW
CURRENTLY OVER THE FOUR CORNERS REGION. THIS LOW IS PROGGED TO
PUSH SLOWLY EWD EARLY SATURDAY BEFORE ITS ENERGY GETS INGESTED AND
HELPS DEEPEN A NORTHERN STREAM TROUGH. THIS TROUGH WILL MOVE ALONG
THE US/CANADIAN BORDER UNTIL THE CLOSED LOW ENERGY PHASES WITH IT
AND MOVES EAST. IN ADDITION TO THE UPPER LEVEL TROUGH...A SFC LOW
IS FORECASTED TO DEVELOP SATURDAY NIGHT OVER THE PLAINS AND AHEAD
OF IT...A STRONG SURGE OF GULF MOISTURE RETURNS TO THE OH AND TN
VALLEYS. PW VALUES UP TO 1.4 INCHES ARE EXPECTED WITH THIS NEW
SURGE OF MOISTURE....WHICH ARE WELL ABOVE AVERAGE. THERE WILL BE
SOME MODERATE INSTABILITY AS WELL. THIS SYSTEM SHOULD PUSH OUT OF
KY BY MONDAY NIGHT. ON TUESDAY...A LOW THAT IS NOW CUT OFF IN THE
NORTHERN STREAM WILL UNDULATE OVER THE GREAT LAKES REGION THROUGH
THURSDAY WITH PIECES OF ENERGY WRAPPING AROUND IT. HOWEVER...THIS
SHOULDN/T CAUSE ANY ISSUES FOR KENTUCKY AS THE ENERGY APPEARS TO
STAY FURTHER NORTH UNTIL THURSDAY WHEN THE LOW STARTS SAGGING
SOUTHEASTWARD.
AT THE SFC...SATURDAY WILL BE MAINLY DRY AND WARM UNTIL LATE
AFTERNOON WHEN CHANCES FOR PRECIP BEGIN INCREASING. THE BULK OF
THE RAINFALL WILL FALL SUNDAY INTO MONDAY WHERE AT LEAST AN INCH
OF LIQUID IS LIKELY ACROSS EASTERN KENTUCKY. THERE IS ALSO A
CHANCE FOR THUNDERSTORMS DURING THIS TIME GIVEN THE MOIST AIR MASS
IN PLACE AND PLENTY OF SFC/UPPER LEVEL DYNAMICS. AS THIS SYSTEM
EXITS THE AREA MONDAY NIGHT...THINGS WILL DRY OUT AND EASTERN
KENTUCKY WILL GET A REPRIEVE FROM PRECIPITATION TUESDAY AND
WEDNESDAY. TEMPERATURES DURING THIS TIME WILL BE A BIT BELOW
NORMAL IF NOT RIGHT AT SEASONABLE LEVELS. RAIN CHANCES RETURN ON
THURSDAY AS THE LOW SAGS SOUTHEASTWARD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM EDT THU APR 16 2015
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
ACROSS EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS. THE OVERALL
TREND OVER THE PAST COUPLE OF HOURS HAS BEEN FOR THE ACTIVITY TO
WEAKEN AND DECREASE IN COVERAGE. THAT BEING SAID...IT LOOKS THERE
WILL BE A MUCH SMALLER CHANCE OF SHOWERS AND STORMS DIRECTLY
AFFECTING ANY OF THE TAF SITES THAN BEFORE. WHERE RAIN DOES
OCCUR...PARTICULARLY WITH THUNDERSTORMS...A TAF SITE MAY
EXPERIENCE BRIEF PERIODS OF MVFR CONDITIONS DURING THE MORE
INTENSE RAIN SHOWERS. THE SHOWERS AND STORMS SHOULD BE MOSTLY OUT
OF THE ARE BY AROUND 2Z THIS EVENING. THERE WILL BE A CHANCE OF
LINGERING SHOWERS AND STORMS OVERNIGHT...AS AN AREA OF DISTURBED
WEATHER PASSES BY THE AREA. ANOTHER BATCH OF ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS IS ON TAP FOR TOMORROW...AS YET ANOTHER
DISTURBANCE MOVES ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS.
THERE SHOULD BE A GOOD LULL IN THE RAIN BETWEEN ROUGHLY 2 AND
12Z...WITH A SLIGHT UPTICK IN THE ACTIVITY AT 12 OR 13Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AR
LONG TERM...JVM
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
306 PM EDT THU APR 16 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 306 PM EDT THU APR 16 2015
WITH THE LATEST RUN OF THE HRRR MODEL BEING A BIT OFF WITH ITS
HANDLING OF TODAYS CONVECTION...THE NAM12 WAS MODEL OF CHOICE FOR
THE SHORT TERM PORTION OF THE FORECAST. SHOWERS AND STORMS THAT
HAVE BEEN MOVING ACROSS EASTERN KENTUCKY THROUGHOUT THE DAY ARE
CURRENTLY AFFECTING THE NORTHEASTERN PORTION OF THE THE AREA. THIS
ACTIVITY IS EXPECTED TO MOVE ON OUT OF THE AREA IN THE NEXT FEW
HOURS. CURRENT RADAR INDICATES THAT ISOLATED TO SCATTERED SHOWERS
AND STORMS WILL CONTINUE TO MOVE INTO THE AREA FROM THE SOUTHWEST
DURING THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ONLY
ISOLATED ACTIVITY...IF THAT...WILL BE LEFT OVER FOR THE OVERNIGHT
HOURS. SHOWERS AND STORMS WILL BE POSSIBLE DURING THE DAY ON
FRIDAY...AS A WEAK FRONTAL BOUNDARY MOVES IN FROM THE WEST. WEAK
DISTURBANCES AHEAD OF THIS FRONT MAY ALSO KICK OFF SHOWERS AND
STORMS...BUT WITH A LACK OF INSTABILITY AND STRONG LIFT...IT
APPEARS THAT THE COVERAGE OF PRECIPITATION WILL BE SPARSE. BASED
ON THE LATEST MODEL DATA...THERE SHOULD BE LULL IN THE ACTION FROM
LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING...AS A WEAK
RIDGE OF HIGH PRESSURE BRIEFLY SETTLES OVER THE AREA.
TEMPERATURES DURING THE PERIOD WILL BE WELL ABOVE NORMAL FOR THIS
TIME OF YEAR...WITH HIGHS ON FRIDAY MAXING OUT IN THE 70S...AND
OVERNIGHT LOWS TONIGHT AND FRIDAY NIGHT BOTTOMING OUT IN THE LOW
TO MID 50S AREA WIDE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM EDT THU APR 16 2015
THE UPPER LEVEL PATTERN REMAINS IN A SPLIT FLOW TO START THE
EXTENDED WITH MAIN CONCERNS CENTERED AROUND A CLOSED LOW WHICH IS
IN THE PROCESS OF CREEPING EAST FROM THE FOUR CORNERS REGION ON
FRIDAY NIGHT. MEANWHILE...ALONG THE NORTHERN JET STREAM...A STRONG
SHORTWAVE IS CURRENTLY ENTERING THE PACIFIC NORTHWEST. AS THE
MENTIONED CLOSED LOW OPENS AND EJECTS TO THE EAST...THESE TWO
FEATURES BEGIN TO PHASE...DEEPENING THE LONGWAVE TROUGH OVER THE
CENTRAL PLAINS AS THIS FEATURE MOVES EAST. CLOSER TO EAST KENTUCKY
DURING THE FRIDAY NIGHT THROUGH SATURDAY TIME FRAME...WEAK
DISTURBANCES ALONG THE SOUTHERN STREAM MOVING INTO THE AREA WILL
KEEP A SLIGHT CHANCE OF PRECIP FRIDAY NIGHT OVER THE AREA. BY
SATURDAY NIGHT...AS THE MENTIONED DEEPENING TROUGH DEVELOPS...A
STRONG SURFACE LOW PRESSURE DEVELOPS OVER THE PLAINS AND A STRONG
SURGE OF MOISTURE MOVES NORTHEAST INTO THE TN AND OH VALLEYS
SATURDAY NIGHT AND SUNDAY BEHIND A DEVELOPED WARM FRONT. PWATS
WITH THIS LOOK TO BE NEAR 1.40 INCHES IN MOST EAST KENTUCKY
LOCATIONS WITH SOME MODEST INSTABILITY THROUGH SUNDAY.
CONCERNING THIS...THE GFS AND EURO HAVE HAD GOOD AGREEMENT WITH
THIS FEATURE AND CONSISTENCY AS WELL. IN FACT...MOS DATA HAS BEEN
ADVERTISING CAT POPS ACROSS EAST KENTUCKY. COLLABORATING WITH
NEIGHBORS AND WHAT THE MODELS HAVE SHOWN...HAVE GONE ABOVE WHAT
THE SUPER BLEND HAS DISPLAYED FOR EAST KENTUCKY. DESPITE THE
DOWNSLOPE FOR THE BEGINNING OF THIS EVENT LATE SATURDAY
NIGHT...THE SURGE IN MOISTURE WITH THIS WILL QUICKLY OVERTAKE THIS
ADIABATIC PROCESS. BESIDE THE MOISTURE AVAILABLE AND POSSIBLE
FLOOD SCENARIO...THE AMOUNT OF SHEAR THE MODEL SOUNDINGS ARE
ADVERTISING IS CONCERNING. THE ONLY INHIBITING FACTOR HERE IS THE
TIMING OF THE PRECIP AND LACK OF STRONG INSTABILITY.
NEVERTHELESS...WILL GO WITH CAT POPS LATE SATURDAY NIGHT THROUGH
SUNDAY AFTERNOON AND LIKELY POPS THROUGH MONDAY AS ADDITIONAL
MOISTURE MOVES INTO THE AREA. THIS TIME FRAME WILL CONTINUE TO BE
HIGHLIGHTED IN THE HWO FOR POSSIBLE FLOODING AND MAY NEED TO
HIGHLIGHT A SEVERE POTENTIAL...THOUGH THIS ELEMENT IS STILL VAGUE
DUE TO THE TIMING...LACK OF DEEP INSTABILITY...AND TIMING WITH THE
BETTER UPPER LEVEL DYNAMICS ARRIVING LATE IN THE PERIOD.
CONTINUED PRECIP WILL LAST INTO MONDAY AND MONDAY NIGHT AS THE
SURFACE COLD FRONT BEGINS TO PUSH THROUGH. LOOKING AT MODEL
SOUNDINGS MONDAY INTO MONDAY NIGHT...ANOTHER PERIOD OF UNSETTLED
WEATHER LOOKS POSSIBLE. HIGH PRESSURE AND RARE QUIET WEATHER WILL
ARRIVE INTO THE AREA BEHIND THE FRONT FOR THE TUESDAY AFTERNOON
THROUGH WEDNESDAY PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM EDT THU APR 16 2015
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
ACROSS EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS. THE OVERALL
TREND OVER THE PAST COUPLE OF HOURS HAS BEEN FOR THE ACTIVITY TO
WEAKEN AND DECREASE IN COVERAGE. THAT BEING SAID...IT LOOKS THERE
WILL BE A MUCH SMALLER CHANCE OF SHOWERS AND STORMS DIRECTLY
AFFECTING ANY OF THE TAF SITES THAN BEFORE. WHERE RAIN DOES
OCCUR...PARTICULARLY WITH THUNDERSTORMS...A TAF SITE MAY
EXPERIENCE BREIF PERIODS OF MVFR CONDITIONS DURING THE MORE
INTENSE RAIN SHOWERS. THE SHOWERS AND STORMS SHOULD BE MOSTLY OUT
OF THE ARE BY AROUND 2Z THIS EVENING. THERE WILL BE A CHANCE OF
LINGERING SHOWERS AND STORMS OVERNIGHT...AS AN AREA OF DISTURBED
WEATHER PASSES BY THE AREA. ANOTHER BATCH OF ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS IS ON TAP FOR TOMORROW...AS YET ANOTHER
DISTURBANCE MOVES ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS.
THERE SHOULD BE A GOOD LULL IN THE RAIN BETWEEN ROUGHLY 2 AND
12Z...WITH A SLIGHT UPTICK IN THE ACTIVITY AT 12 OR 13Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AR
LONG TERM...SHALLENBERGER
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
213 AM EDT THU APR 16 2015
.UPDATE...
ISSUED AT 213 AM EDT THU APR 16 2015
SHOWERS ARE BEGINNING TO MOVE INTO THE LAKE CUMBERLAND REGION IN
RESPONSE TO AN APPROACHING UPPER LEVEL SHORTWAVE. SHOWER COVERAGE
IS EXPECTED TO GRADUALLY INCREASE THROUGH THE MORNING AS THIS
SHORTWAVE MOVES THROUGH THE AREA. NEAR TERM MODELS INDICATE TWO
WAVES OF SHOWERS AND A FEW THUNDERSTORMS TODAY AND POPS WERE
ADJUSTED TO ACCOUNT FOR THE MORNING PRECIP...FOLLOWED BY A BRIEF
LULL AND THEN ANOTHER UPTICK IN SHOWERS AND A FEW THUNDERSTORMS IN
THE AFTERNOON. WE SHOULD NOT BE ABLE TO ACHIEVE THE AMOUNT OF
INSTABILITY CURRENTLY FOUND OVER WESTERN AND CENTRAL TENNESSEE
TODAY...SO DO NOT ANTICIPATE THE STRONG TO OCCASIONALLY SEVERE
THUNDERSTORMS FOUND THERE TO BE ABLE TO MAINTAIN THERE STRENGTH
THIS FAR NORTH AND EAST.
UPDATE ISSUED AT 941 PM EDT WED APR 15 2015
GENERALLY ISOLATED SHOWERS CONTINUE ACROSS THE CWA LATE THIS
EVENING..WITH MORE SCATTERED ACTIVITY ACROSS THE NORTH CENTRAL
PORTION OF THE STATE ALONG A WEAK BOUNDARY. HEAVIER SHOWERS AND
THUNDERSTORMS REMAIN WELL TO OUR SOUTHWEST ACROSS WESTERN
TN...CLOSER TO THE SURFACE LOW PRESSURE CENTER LOCATED NEAR THE
SAME AREA. THIS LOW WILL CONTINUE TO SLOWLY SHIFT NE THROUGHOUT
THE NIGHT...REACHING FAR WESTERN KY BY 12Z TOMORROW. THIS MAY
ALLOW SOME MORE SHOWERS AND POSSIBLY EVEN AN ISOLATED
THUNDERSTORM TO DEVELOP AND MOVE INTO THE CWA LATER IN THE NIGHT
AND EARLY IN THE MORNING. BUT IN THE MEANTIME...IT LOOKS AS THINGS
ARE STARTING TO SETTLE DOWN ACROSS THE REGION.
CONTINUED CLOUD COVER...A HIGH AMOUNT OF MOISTURE...AND LIGHT
WINDS...WILL HELP TO MODERATE THE TEMPERATURES OVERNIGHT. CURRENT
READINGS OF UPPER 50S HAVE BEEN INCORPORATED INTO THE NEAR TERM
FORECAST...WITH ONLY A 3 TO 5 DEGREE DIURNAL FALL INTO THE LOW TO
MID 50S EXPECTED BY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 340 PM EDT WED APR 15 2015
18Z SFC ANALYSIS SHOWS THAT THE INVERTED TROUGH AXIS HAS SHIFTED
EAST TO ALONG THE SPINE OF THE APPALACHIANS WITH THE LOWER
MISSISSIPPI VALLEY LOW/S WARM FRONT LIFTING NORTH INTO KENTUCKY.
THE LIGHT PCPN AND OVERCAST CONDITIONS HAS KEPT MOST OF THE AREA
ON THE COOL SIDE TODAY...ESPECIALLY OUTSIDE OF THE CUMBERLAND
VALLEY. HOWEVER...THINNING CLOUDS AND A BREAK IN THE LIGHT RAIN
SHOULD ALLOW FOR SOME DECENT TEMP RISES OVER THE NEXT COUPLE OF
HOURS FOR ALL BUT THE FAR NORTHEAST. READINGS CURRENTLY VARY FROM
THE UPPER 50S IN THE NORTHEAST TO THE UPPER 60S IN THE SOUTH WHILE
DEWPOINTS RANGE FROM NEAR 60 SOUTH TO THE UPPER 40S IN THE FAR
NORTH. WINDS ARE GENERALLY FROM THE EAST TO NORTHEAST AT 10 TO 15
MPH OVER THE NORTHERN HALF OF THE AREA WHILE THEY ARE A BIT
LIGHTER AND MORE VARIABLE TO THE SOUTH. THE LIFTING WARM FRONT
MAY REINITIATE SHOWERS LATER IN THE AFTERNOON INTO THE EVENING...
PER THE LATEST HRRR AND NAM12...BUT RIGHT NOW THE RADAR SCOPE IS
PRETTY CLEAN. SHOULD CONVECTION REDEVELOP...SOME THUNDER MAY EVEN
BE POSSIBLE GIVEN THE RISING TEMPS/INSTABILITY...ESPECIALLY IN
THE SOUTH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST AS A FEW CLUSTERS OF MID LEVEL ENERGY WILL
BRUSH KENTUCKY AS THEY MOVE INTO THE OHIO VALLEY TONIGHT ON THE
NORTHWEST FRINGE OF A BUILDING RIDGE. THE RIDGE FLATTENS A BIT ON
THURSDAY AS ADDITIONAL ENERGY PASSES THROUGH NORTHERN KENTUCKY
THAT AFTERNOON/OVERNIGHT AND INTO FRIDAY MORNING. TO THE WEST...A
SLOW MOVING CLOSED LOW SPINS ESSENTIALLY IN PLACE NEAR THE FOUR
CORNERS REGION OF THE COUNTRY...SERVING AS A SOURCE REGION FOR
ENERGY ABLE TO ESCAPE AND DRIFT EAST IN THE SOUTHERN STREAM THAT
CONTINUES TO DOMINATE KENTUCKY/S WX. GIVEN THE GENERAL MODEL
AGREEMENT HAVE FOLLOWED A BLEND WITH A LEAN TOWARD THE HRRR AND
NAM12 FOR WEATHER SPECIFICS DUE TO THEIR HIGHER RESOLUTION...
THOUGH CURRENT CONDITIONS AND TRENDS ARE ALSO OF HIGH RELEVANCE
INTO THE NEAR TERM PORTION OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A POTENTIAL FOR SHOWERS INTO THE
EVENING AS THE SFC FRONT LIFTS NORTHEAST THROUGH THE AREA WITH A
THUNDERSTORM POSSIBLE...AS WELL. ADDITIONAL CONVECTION WILL BE
POSSIBLE INTO THURSDAY MORNING WITH THE SFC LOW TO THE SOUTHWEST
APPROACHING. THIS WILL LIKELY LIFT ANOTHER BOUNDARY THROUGH
EASTERN KENTUCKY DURING THE DAY WITH SHOWERS AND STRAY STORMS A
GOOD BET. THE PCPN CHANCES WILL DIMINISH INTO FRIDAY MORNING BUT
CANNOT GO DRY ATTM GIVEN THE ENVIRONMENT. THIS REMAINS A LOW
CONFIDENCE FORECAST WITH RESPECT TO SPECIFIC DETAILS BUT IN
GENERAL YOU CAB BANK ON RELATIVELY WARM AND MOIST CONDITIONS
CONTINUING.
USED THE SHORTBLEND GUIDANCE AS A STARTING POINT FOR T/TD/WIND
GRIDS THROUGH THE FIRST 18-24 HOURS OF THE FORECAST FOLLOWED BY
THE SUPERBLEND. GIVEN THE HUMID CONDITIONS MADE ONLY MINOR TERRAIN
BASED ADJUSTMENTS TO TEMPERATURES TONIGHT AND THURSDAY NIGHT. AS
FOR POPS...ENDED UP ON THE LOW SIDE OF MOS GUIDANCE TONIGHT AND
THURSDAY...BUT IN LINE FOR THURSDAY NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 PM EDT WED APR 15 2015
THE EXTENDED PERIOD WILL BE DOMINATED BY A LARGE CLOSED LOW OVER THE
FOUR CORNERS REGION WITH SOME SLIGHT RIDGING OVER THE EASTERN CONUS.
AFTER A SHORT WAVE IMPULSE...PROVIDING A ROUND OF RAINFALL TO THE
REGION...PUSHES THROUGH THE TN AND OH VALLEYS FRIDAY MORNING...
FRIDAY EVENING INTO SATURDAY MORNING WILL BE MOSTLY DRY. ON
SATURDAY...ANOTHER IMPULSE MOVING ALONG THE NORTHERN STREAM PUSHES
EWD TOWARDS THE GREAT LAKES REGION. AT THE SAME TIME...THE CLOSED
LOW EJECTS EWD AS WELL. THE ENERGY FROM THE CLOSED LOW THEN FEEDS
INTO THE NORTHERN STREAM TROUGH AND HELPS DEEPEN/INTENSIFY IT. THIS
SYSTEM WILL PROVIDE THE BEST CHANCE FOR A SIGNIFICANT AMOUNT OF
RAINFALL FOR EASTERN KENTUCKY IN THE SATURDAY NIGHT THROUGH MONDAY
MORNING TIME FRAME. THIS RAINFALL HAS THE POSSIBILITY OF BREAKING
THE JKL/S ALL-TIME APRIL RAINFALL RECORD...CURRENTLY WE HAVE HAD THE
SECOND WETTEST APRIL ON RECORD. IN FACT...THIS SYSTEM WILL SPREAD
PRECIP FROM THE NORTHERN MISSISSIPPI VALLEY REGION ACROSS MOST OF
THE EASTERN CONUS THROUGH TUESDAY. CLOSER TO HOME...TUESDAY AND
WEDNESDAY LOOKS TO BE FAIRLY QUIET...COOLER...AND DRY AS THE UPPER
LEVELS TRANSITION TO MORE OF A ZONAL FLOW PATTERN.
GFS AND ECMWF MODELS ACTUALLY HAVE GOOD AGREEMENT WITH THE EVOLUTION
OF THIS MAJOR SYSTEM. ADDITIONALLY...THERE LOOKS TO BE A STRONG
SURGE OF GULF MOISTURE WITH PW VALUES REACHING 1.50 INCHES IN SOME
LOCATIONS WITH SOME INSTABILITY PRESENT. THEREFORE...HAVE DECIDED TO
INCLUDED SLIGHT CHANCES OF THUNDER THROUGHOUT THE EXTENDED PERIOD
WITH LIKELY THUNDER DURING THE SUNDAY AFTERNOON THROUGH MONDAY
MORNING TIME FRAME. PROBABLY COULD HAVE UPPED POPS TO GO CATEGORICAL
ON SUNDAY/MONDAY MORNING BUT HAVE REMAINED CONSISTENT WITH NEIGHBORS
FOR NOW AND KEPT LIKELY POPS IN THE GRIDS. ALL IN ALL...BASED ON THE
CONTINUED WET PATTERN...THE MAIN CONCERN DURING THE EXTENDED PERIOD
WILL BE HEAVY RAINFALL WITH LOCALIZED FLOODING CONCERNS...ESPECIALLY
IN AREAS THAT RECEIVE SEVERAL ROUNDS OF RAINFALL AND WHERE RIVERS
AND CREEKS ARE STILL RUNNING HIGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 213 AM EDT THU APR 16 2015
LOW LEVEL SOUTHEASTERLY FLOW HAS WORKED TO SCOUR OUT THE EARLIER
LOW CLOUDS WITH MAINLY VFR CONDITIONS FOUND ACROSS EAST KENTUCKY
AT THIS TIME. AN APPROACHING UPPER LEVEL DISTURBANCE WILL BRING AN
INCREASE IN SHOWERS...AND MAYBE A THUNDERSTORM...THROUGH THE
MORNING HOURS...WITH MVFR CONDITIONS LIKELY FOR A PERIOD OF TIME.
THE MORNING SHOWERS SHOULD SHIFT TO OUR EAST DURING THE MIDDAY
HOURS WITH VFR CONDITIONS EXPECTED AND JUST WIDELY SCATTERED
SHOWERS LEFT BEHIND. NEAR TERM MODELS THEN INDICATE ADDITIONAL
FORCING DURING THE AFTERNOON HOURS AND THIS MAY PRODUCE ANOTHER
UPTICK IN SHOWER COVERAGE WITH A THUNDERSTORM OR TWO ALSO
POSSIBLE. STILL UNSURE HOW WIDESPREAD THAT SECOND ROUND WILL
BECOME SO JUST KEPT WITH A VCSH MENTION FROM MIDDAY ON IN THE
TAFS FOR RIGHT NOW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW/ABE
SHORT TERM...GREIF
LONG TERM...JVM
AVIATION...ABE
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
832 AM CDT THU APR 16 2015
...SOUNDING DISCUSSION...
THE ATMOSPHERE CONTINUES TO REMAIN MOISTURE-LADEN WITH
PRECIPITABLE WATER VALUES REMAINING WELL ABOVE NORMAL. THAT LINE
WILL CONTINUE TO BE REPEATED THROUGH THE REST OF THE WEEK AND
INTO THE WEEKEND. FORECAST CAPE VALUES WILL APPROACH 1500 J/KG AND
LI WILL DROP TO -4 LATER TODAY. FREEZING LEVEL IS AROUND
12700 FEET...WHICH IS SIMILAR TO LAST EVENING. HOWEVER...WET BULB
ZERO HEIGHT IS ABOUT 1000 FEET HIGHER THAN LAST NIGHT. THERE IS
SOME DRY AIR SHOWN IN THE SOUNDING AROUND 17000 FEET THAT WOULD
SUPPORT A DAMAGING WIND GUST POTENTIAL. MAIN FOCUS FOR TODAY WILL
BE THREAT FOR HEAVY RAINFALL. THERE IS SOME DIRECTIONAL AND SPEED
SHEAR...BUT STORM RELATIVE HELICITY VALUES ARE LOW SO TORNADO
THREAT IS ALSO QUITE LOW. WINDS WERE FROM THE SOUTHEAST AT THE
SURFACE AND THEN ROTATED AROUND TO THE WEST BY THE MIDLEVELS. A
29 KNOT WIND WAS OBSERVED AT 500MB AND A PEAK WIND SPEED OF 93
KNOTS WAS FOUND AT 38400 FEET/217MB.
12Z BALLOON INFO: NO ISSUES WITH THE FLIGHT THIS MORNING THAT
LASTED 105 MINUTES. THE BALLOON REACHED A HEIGHT OF 21 MILES
ABOVE THE GROUND AND WENT 53 MILES DOWNRANGE BURSTING EAST OF
MCHENRY.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 414 AM CDT THU APR 16 2015/
SHORT TERM...
LITTLE CHANGE IN THINKING FROM THE PREVIOUS FORECAST...AS THE AREA
REMAINS UNDER THE INFLUENCE OF A BROAD REGION OF ENHANCED OMEGA
THROUGH SATURDAY AS A SLOW MOVING UPPER LEVEL TROUGH OVER THE FOUR
CORNERS DRIFTS THROUGH THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH PULSES UP INCREASED VORTICITY EJECTING OUT OF THE BASE OF THE
PARENT UPPER LEVEL LOW WILL IMPACT THE REGION THROUGH THIS
PERIOD...WITH THE RISK OF HEAVY RAINFALL AND LOCALLY SEVERE
THUNDERSTORMS EACH DAY. HOWEVER... THE RISK OF SEVERE
THUNDERSTORM DEVELOPMENT WILL BE GREATEST ON FRIDAY AND SATURDAY
AS OVERALL LAPSE RATES AND SHEAR PROFILES LOOK MORE FAVORABLE ON
THESE DAYS. THERE WILL BE A THREAT OF HEAVY RAINFALL THREAT EVERY
DAY AS PW VALUES REMAIN ELEVATED AT AROUND 1.75 INCHES AND THE
ATMOSPHERE REMAINS MOISTURE LOADED. GIVEN THIS THREAT...THE FLASH
FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY EVENING. THE WATCH
MAY NEED TO BE EXTENDED INTO SATURDAY LATER TODAY.
FOR TODAY...AFTER REVIEWING THE GFSBUFR SOUNDINGS AND LOOKING AT
THE LATEST HRRR OUTPUT...EXPECT TO SEE CONVECTION INITIALLY IMPACT
AREAS AROUND BATON ROUGE THIS MORNING AND THEN SPREAD SOUTH AND
EAST INTO NEW ORLEANS AND THE MISSISSIPPI GULF COAST DURING THE
AFTERNOON AND EVENING HOURS. SOUNDING PROFILES ARE NOT AS
SUPPORTIVE OF SEVERE THUNDERSTORMS TODAY...AS MID-LEVEL LAPSE
RATES ARE CLOSER TO MOIST ADIABATIC AND THE WET BULB ZERO HEIGHT
REMAINS AROUND 13K FEET. ADDITIONALLY...THERE IS VERY LITTLE WIND SHEAR
NOTED OVER THE AREA. SPC HAS ONLY A MARGINAL RISK OF SEVERE
THUNDERSTORM DEVELOPMENT TODAY GIVEN THESE WEAKER PARAMETERS.
THE SOUNDING IS SUPPORTIVE OF LOCALLY HEAVY RAINFALL DEVELOPING
TODAY. THERE IS LITTLE IN THE WAY OF CONVECTIVE INHIBITION...SO IT
WILL NOT TAKE MUCH TO GET THUNDERSTORMS GOING. THESE THUNDERSTORMS
WILL HAVE A VERY EFFICIENT RAIN PROCESS...WHICH WILL ALLOW FOR
RAINFALL RATES OF UP TO 2 INCHES PER HOUR AT TIMES. THUS...SOME
LOCALIZED FLOODING WILL BE THREAT TODAY.
HEADING INTO TONIGHT...MUCH AS SEEN THE LAST FEW NIGHTS...THE
THUNDERSTORM ACTIVITY WILL QUICKLY DIMINISH AS DAYTIME HEATING
GIVES WAY. THERE WILL BE A RISK OF SOME SCATTERED SHOWERS AND B
THUNDERSTORMS DEVELOPING DURING THE NIGHT...BUT OVERALL COVERAGE
WILL BE MUCH LOWER THAN DURING THE PEAK HEATING HOURS.
TEMPERATURES WILL ONCE AGAIN COOL BACK INTO THE MIDDLE TO UPPER
60S...AND SOME PATCHY FOG WILL DEVELOP TOWARD DAYBREAK DUE TO THE
WET GROUND CONDITIONS AND A WEAK LOW LEVEL INVERSION CUTTING OFF
THE BOUNDARY LAYER WINDS. FOG COVERAGE LOOKS TO BE LOW ENOUGH TO
KEEP OUT OF THE OFFICIAL FORECAST FOR NOW.
FRIDAY LOOKS TO BE A VERY ACTIVE DAY ACROSS THE REGION. GFSBUFR
SOUNDINGS SHOW A MUCH MORE FAVORABLE ENVIRONMENT FOR SEVERE
THUNDERSTORM DEVELOPMENT...ESPECIALLY FROM LATE MORNING ON. MID-
LEVEL LAPSE RATES WILL INCREASE DRAMATICALLY FRIDAY
AFTERNOON...SHOOTING UP TO 7 C/KM BETWEEN 700 AND 500 MB. THESE
HIGH LAPSE RATES WILL ALSO BE ABOVE THE FREEZING LEVEL WHICH WILL
FALL BELOW 13K FEET. ADDITIONALLY...WET BULB ZERO HEIGHTS WILL
DROP TO AROUND 11K FEET. WITH STRONG LAPSE RATES IN THE HAIL
GROWTH ZONE...SOME LARGE HAIL WILL ONCE AGAIN BE POSSIBLE ON
FRIDAY. LOOKING AT THE WIND PROFILE...OVERALL HELICITY VALUES WILL
BE FAIRLY WEAK ON FRIDAY...BUT WITH SOME DRY AIR ADVECTING INTO
THE MID-LEVELS...THE THREAT OF STRAIGHT LINE WINDS AND BOWING
SEGMENTS INCREASES. THERE IS ENOUGH LOW LEVEL HELICITY...THAT AN
ISOLATED TORNADO COULD NOT BE RULED OUT FRIDAY AFTERNOON.
OVERALL...EXPECT THE MAIN THREAT TO BE HAIL AND STRAIGHT LINE
WINDS ON FRIDAY. CONDITIONS WILL ONCE AGAIN IMPROVE DURING THE
EVENING HOURS ON FRIDAY AS THE VORT MAX SLIDES TO THE EAST AND THE
ATMOSPHERE STABILIZES A BIT.
HOWEVER...THE PARENT UPPER LEVEL TROUGH WILL BEGIN TO DIRECTLY
IMPACT THE REGION ON SATURDAY AS IT MOVES THROUGH THE SOUTHERN
PLAINS. SATURDAY LOOKS TO HAVE THE HIGHEST THREAT OF BOTH HEAVY
RAINFALL AND SEVERE THUNDERSTORMS. PW VALUES WILL BE VERY
HIGH...APPROACHING 2 INCHES...AND THE OVERALL LAPSE RATES WILL
TURN MORE MOIST ADIABATIC THROUGH THE DAY. THIS WILL DECREASE THE
HAIL THREAT SUBSTANTIALLY...WITH WET BULB ZERO HEIGHTS REMAINING
WELL ABOVE 13K FEET. HOWEVER...VERY EFFICIENT RAINFALL PROCESSES
WILL DEVELOP...RESULTING IN HOURLY RAINFALL RATE POTENTIAL OF 2 TO
3 INCHES IF A STORM STALLS OVER THE SAME AREA. FORTUNATELY...THE
STORMS WILL BE FAST MOVING...SO ACTUAL RAINFALL RATES WILL BE
LOWER. THESE STRONG WINDS WILL UNFORTUNATELY MEAN THAT THE RISK OF
STRAIGHT LINE WINDS AND TORNADOES WILL BE HIGH ON SATURDAY. 0-3KM
SHEAR WILL INCREASE TO AROUND 35 KNOTS AND STORM RELATIVE HELICITY
VALUES WILL RISE TO AROUND 250 M2/S2 SATURDAY AFTERNOON. THESE
VALUES ARE VERY CONDUCIVE TO ROTATING THUNDERSTORM
DEVELOPMENT...AND THUS THE FORMATION OF TORNADOES. A FRONTAL
BOUNDARY WILL PUSH THROUGH THE AREA SATURDAY NIGHT...WHICH WILL
KEEP THE RISK OF SHOWERS AND THUNDERSTORMS IN PLACE THROUGH THE
NIGHT...AND HAVE LIKELY POPS IN PLACE TO REFLECT THIS.
LONG TERM...
CONDITIONS WILL BEGIN TO IMPROVE ON SUNDAY...AS A COLD FRONT
PUSHES OFFSHORE AND RAIN CHANCES SHOULD DECREASE THROUGH THE DAY
FROM WEST TO EAST. THE PARENT UPPER LEVEL TROUGH AXIS WILL FINALLY
PUSH THROUGH THE REGION SUNDAY NIGHT...WITH INCREASING NEGATIVE
VORTICITY ADVECTION AND SUBSIDENCE TAKING HOLD OF THE AREA FOR
MONDAY. AT MOST...THERE COULD BE SOME LINGERING SHOWERS AND CLOUDS
ALONG THE IMMEDIATE COAST MONDAY MORNING...WITH CLEARING
CONDITIONS EXPECTED BY MONDAY AFTERNOON. AS A MORE ZONAL FLOW
REGIME TAKES HOLD ALOFT...AND SOME DRIER MID-LEVEL AIR LINGERS
OVER THE AREA SKIES SHOULD REMAIN PARTLY CLOUDY AND RAIN CHANCES
WILL BE LESS THAN 10 PERCENT FOR TUESDAY. TEMPERATURES WILL REMAIN
NEAR NORMAL...WITH HIGHS IN THE LOWER 80S AND LOWS IN THE UPPER
50S AND LOWER 60S.
UNFORTUNATELY...A WEAK IMPULSE RIDING ALONG THE ZONAL FLOW WILL
SLIDE THROUGH THE AREA ON WEDNESDAY. THE SYSTEM WILL BE FAIRLY
WEAK...BUT ENOUGH FORCING AND MOISTURE WILL BE IN PLACE TO SPARK
OFF SOME SCATTERED SHOWERS AND THUNDERSTORMS DURING THE DAY ON
WEDNESDAY. RAIN CHANCES WILL BE HIGHEST ALONG THE COAST AND
OFFSHORE WHERE OVERALL MOISTURE AND FORCING IS EXPECTED TO BE
GREATEST. AS THIS FEATURE PULLS TO THE EAST WEDNESDAY...SKIES
SHOULD CLEAR AND RAIN CHANCES WILL DROP. HOWEVER...ANOTHER IMPULSE
WILL SLIDE THROUGH ON THURSDAY...BRINGING ANOTHER CHANCE OF
ISOLATED SHOWERS AND THUNDERSTORMS FOR THURSDAY.
AVIATION...
TAFS WILL BE DEPENDENT ONCE AGAIN ON EVENTUAL CONVECTIVE DEVELOPMENTS TODAY.
CONVECTIVE BASED MODELS SUGGEST ONSET OF STORMS COULD IMPACT SOME LOCATIONS
BY 14Z...PRIMARILY WESTERNMOST LOCATIONS LIKE KBTR AND KHUM...THOUGH ALL
TERMINALS SHOULD SEE SOME PERIODS OF TSRA/SHRA THROUGHOUT THE DAY. DOWN BURST
POTENTIAL WILL BE HIGH TODAY WITH GUST POTENTIAL 35-45 KT. EFFICIENT RAINFALL
PROCESS SHOULD ALSO LOWER VSBY TO VLIFR LEVELS AT TIMES DURING HEAVY RAINFALL.
OTHERWISE...VFR CONDITIONS SHOULD PREVAIL AFTER 16Z OUTSIDE
CONVECTION.
MARINE...
AN INTERESTING WAKE LOW PHENOMENA IMPACTED THE OFFSHORE WATERS
THIS MORNING...BUT THIS HAS SINCE WEAKENED. OVERALL...EXPECT TO
SEE AN ONSHORE FLOW OF 10 TO 15 KNOTS REMAIN OVER THE COASTAL
WATERS THROUGH FRIDAY. AS AN UPPER LEVEL LOW AND ASSOCIATED WEAK
SURFACE LOW AND FRONT MOVE THROUGH OVER THE WEEKEND...WINDS WILL
INCREASE INTO EXERCISE CAUTION RANGE SATURDAY AND REMAIN ELEVATED
INTO SUNDAY. SEAS WILL RESPOND AND INCREASE TO 3 TO 5 FEET IN THE
OFFSHORE WATERS. THE GRADIENT WILL EASE OVER THE AREA ON
MONDAY...ALLOWING FOR WEAKER AND MORE VARIABLE FLOW OF 10 KNOTS OR
LESS. SEAS WILL ALSO FALL BACK INTO THE 1 TO 3 FEET RANGE FOR
MONDAY AND TUESDAY.
DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING HEAVY RAINFALL/FLOODING POTENTIAL
ASSESSING SEVERE WEATHER THREAT THRU WEEKEND.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TONIGHT RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 78 65 79 66 / 80 60 70 50
BTR 79 66 81 67 / 80 60 70 50
ASD 78 67 80 68 / 70 70 70 60
MSY 78 69 80 69 / 70 70 70 60
GPT 77 68 78 69 / 70 70 70 70
PQL 78 67 79 69 / 70 70 70 70
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR LAZ040-046>050-
056>070-072.
GM...NONE.
MS...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR MSZ077-080>082.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
414 AM CDT THU APR 16 2015
.SHORT TERM...
LITTLE CHANGE IN THINKING FROM THE PREVIOUS FORECAST...AS THE AREA
REMAINS UNDER THE INFLUENCE OF A BROAD REGION OF ENHANCED OMEGA
THROUGH SATURDAY AS A SLOW MOVING UPPER LEVEL TROUGH OVER THE FOUR
CORNERS DRIFTS THROUGH THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY. SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH PULSES UP INCREASED VORTICITY EJECTING OUT OF THE BASE OF THE
PARENT UPPER LEVEL LOW WILL IMPACT THE REGION THROUGH THIS
PERIOD...WITH THE RISK OF HEAVY RAINFALL AND LOCALLY SEVERE
THUNDERSTORMS EACH DAY. HOWEVER... THE RISK OF SEVERE
THUNDERSTORM DEVELOPMENT WILL BE GREATEST ON FRIDAY AND SATURDAY
AS OVERALL LAPSE RATES AND SHEAR PROFILES LOOK MORE FAVORABLE ON
THESE DAYS. THERE WILL BE A THREAT OF HEAVY RAINFALL THREAT EVERY
DAY AS PW VALUES REMAIN ELEVATED AT AROUND 1.75 INCHES AND THE
ATMOSPHERE REMAINS MOISTURE LOADED. GIVEN THIS THREAT...THE FLASH
FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY EVENING. THE WATCH
MAY NEED TO BE EXTENDED INTO SATURDAY LATER TODAY.
FOR TODAY...AFTER REVIEWING THE GFSBUFR SOUNDINGS AND LOOKING AT
THE LATEST HRRR OUTPUT...EXPECT TO SEE CONVECTION INITIALLY IMPACT
AREAS AROUND BATON ROUGE THIS MORNING AND THEN SPREAD SOUTH AND
EAST INTO NEW ORLEANS AND THE MISSISSIPPI GULF COAST DURING THE
AFTERNOON AND EVENING HOURS. SOUNDING PROFILES ARE NOT AS
SUPPORTIVE OF SEVERE THUNDERSTORMS TODAY...AS MID-LEVEL LAPSE
RATES ARE CLOSER TO MOIST ADIABATIC AND THE WET BULB ZERO HEIGHT
REMAINS AROUND 13K FEET. ADDITIONALLY...THERE IS VERY LITTLE WIND SHEAR
NOTED OVER THE AREA. SPC HAS ONLY A MARGINAL RISK OF SEVERE
THUNDERSTORM DEVELOPMENT TODAY GIVEN THESE WEAKER PARAMETERS.
THE SOUNDING IS SUPPORTIVE OF LOCALLY HEAVY RAINFALL DEVELOPING
TODAY. THERE IS LITTLE IN THE WAY OF CONVECTIVE INHIBITION...SO IT
WILL NOT TAKE MUCH TO GET THUNDERSTORMS GOING. THESE THUNDERSTORMS
WILL HAVE A VERY EFFICIENT RAIN PROCESS...WHICH WILL ALLOW FOR
RAINFALL RATES OF UP TO 2 INCHES PER HOUR AT TIMES. THUS...SOME
LOCALIZED FLOODING WILL BE THREAT TODAY.
HEADING INTO TONIGHT...MUCH AS SEEN THE LAST FEW NIGHTS...THE
THUNDERSTORM ACTIVITY WILL QUICKLY DIMINISH AS DAYTIME HEATING
GIVES WAY. THERE WILL BE A RISK OF SOME SCATTERED SHOWERS AND B
THUNDERSTORMS DEVELOPING DURING THE NIGHT...BUT OVERALL COVERAGE
WILL BE MUCH LOWER THAN DURING THE PEAK HEATING HOURS.
TEMPERATURES WILL ONCE AGAIN COOL BACK INTO THE MIDDLE TO UPPER
60S...AND SOME PATCHY FOG WILL DEVELOP TOWARD DAYBREAK DUE TO THE
WET GROUND CONDITIONS AND A WEAK LOW LEVEL INVERSION CUTTING OFF
THE BOUNDARY LAYER WINDS. FOG COVERAGE LOOKS TO BE LOW ENOUGH TO
KEEP OUT OF THE OFFICIAL FORECAST FOR NOW.
FRIDAY LOOKS TO BE A VERY ACTIVE DAY ACROSS THE REGION. GFSBUFR
SOUNDINGS SHOW A MUCH MORE FAVORABLE ENVIRONMENT FOR SEVERE
THUNDERSTORM DEVELOPMENT...ESPECIALLY FROM LATE MORNING ON. MID-
LEVEL LAPSE RATES WILL INCREASE DRAMATICALLY FRIDAY
AFTERNOON...SHOOTING UP TO 7 C/KM BETWEEN 700 AND 500 MB. THESE
HIGH LAPSE RATES WILL ALSO BE ABOVE THE FREEZING LEVEL WHICH WILL
FALL BELOW 13K FEET. ADDITIONALLY...WET BULB ZERO HEIGHTS WILL
DROP TO AROUND 11K FEET. WITH STRONG LAPSE RATES IN THE HAIL
GROWTH ZONE...SOME LARGE HAIL WILL ONCE AGAIN BE POSSIBLE ON
FRIDAY. LOOKING AT THE WIND PROFILE...OVERALL HELICITY VALUES WILL
BE FAIRLY WEAK ON FRIDAY...BUT WITH SOME DRY AIR ADVECTING INTO
THE MID-LEVELS...THE THREAT OF STRAIGHT LINE WINDS AND BOWING
SEGMENTS INCREASES. THERE IS ENOUGH LOW LEVEL HELICITY...THAT AN
ISOLATED TORNADO COULD NOT BE RULED OUT FRIDAY AFTERNOON.
OVERALL...EXPECT THE MAIN THREAT TO BE HAIL AND STRAIGHT LINE
WINDS ON FRIDAY. CONDITIONS WILL ONCE AGAIN IMPROVE DURING THE
EVENING HOURS ON FRIDAY AS THE VORT MAX SLIDES TO THE EAST AND THE
ATMOSPHERE STABILIZES A BIT.
HOWEVER...THE PARENT UPPER LEVEL TROUGH WILL BEGIN TO DIRECTLY
IMPACT THE REGION ON SATURDAY AS IT MOVES THROUGH THE SOUTHERN
PLAINS. SATURDAY LOOKS TO HAVE THE HIGHEST THREAT OF BOTH HEAVY
RAINFALL AND SEVERE THUNDERSTORMS. PW VALUES WILL BE VERY
HIGH...APPROACHING 2 INCHES...AND THE OVERALL LAPSE RATES WILL
TURN MORE MOIST ADIABATIC THROUGH THE DAY. THIS WILL DECREASE THE
HAIL THREAT SUBSTANTIALLY...WITH WET BULB ZERO HEIGHTS REMAINING
WELL ABOVE 13K FEET. HOWEVER...VERY EFFICIENT RAINFALL PROCESSES
WILL DEVELOP...RESULTING IN HOURLY RAINFALL RATE POTENTIAL OF 2 TO
3 INCHES IF A STORM STALLS OVER THE SAME AREA. FORTUNATELY...THE
STORMS WILL BE FAST MOVING...SO ACTUAL RAINFALL RATES WILL BE
LOWER. THESE STRONG WINDS WILL UNFORTUNATELY MEAN THAT THE RISK OF
STRAIGHT LINE WINDS AND TORNADOES WILL BE HIGH ON SATURDAY. 0-3KM
SHEAR WILL INCREASE TO AROUND 35 KNOTS AND STORM RELATIVE HELICITY
VALUES WILL RISE TO AROUND 250 M2/S2 SATURDAY AFTERNOON. THESE
VALUES ARE VERY CONDUCIVE TO ROTATING THUNDERSTORM
DEVELOPMENT...AND THUS THE FORMATION OF TORNADOES. A FRONTAL
BOUNDARY WILL PUSH THROUGH THE AREA SATURDAY NIGHT...WHICH WILL
KEEP THE RISK OF SHOWERS AND THUNDERSTORMS IN PLACE THROUGH THE
NIGHT...AND HAVE LIKELY POPS IN PLACE TO REFLECT THIS.
.LONG TERM...
CONDITIONS WILL BEGIN TO IMPROVE ON SUNDAY...AS A COLD FRONT
PUSHES OFFSHORE AND RAIN CHANCES SHOULD DECREASE THROUGH THE DAY
FROM WEST TO EAST. THE PARENT UPPER LEVEL TROUGH AXIS WILL FINALLY
PUSH THROUGH THE REGION SUNDAY NIGHT...WITH INCREASING NEGATIVE
VORTICITY ADVECTION AND SUBSIDENCE TAKING HOLD OF THE AREA FOR
MONDAY. AT MOST...THERE COULD BE SOME LINGERING SHOWERS AND CLOUDS
ALONG THE IMMEDIATE COAST MONDAY MORNING...WITH CLEARING
CONDITIONS EXPECTED BY MONDAY AFTERNOON. AS A MORE ZONAL FLOW
REGIME TAKES HOLD ALOFT...AND SOME DRIER MID-LEVEL AIR LINGERS
OVER THE AREA SKIES SHOULD REMAIN PARTLY CLOUDY AND RAIN CHANCES
WILL BE LESS THAN 10 PERCENT FOR TUESDAY. TEMPERATURES WILL REMAIN
NEAR NORMAL...WITH HIGHS IN THE LOWER 80S AND LOWS IN THE UPPER
50S AND LOWER 60S.
UNFORTUNATELY...A WEAK IMPULSE RIDING ALONG THE ZONAL FLOW WILL
SLIDE THROUGH THE AREA ON WEDNESDAY. THE SYSTEM WILL BE FAIRLY
WEAK...BUT ENOUGH FORCING AND MOISTURE WILL BE IN PLACE TO SPARK
OFF SOME SCATTERED SHOWERS AND THUNDERSTORMS DURING THE DAY ON
WEDNESDAY. RAIN CHANCES WILL BE HIGHEST ALONG THE COAST AND
OFFSHORE WHERE OVERALL MOISTURE AND FORCING IS EXPECTED TO BE
GREATEST. AS THIS FEATURE PULLS TO THE EAST WEDNESDAY...SKIES
SHOULD CLEAR AND RAIN CHANCES WILL DROP. HOWEVER...ANOTHER IMPULSE
WILL SLIDE THROUGH ON THURSDAY...BRINGING ANOTHER CHANCE OF
ISOLATED SHOWERS AND THUNDERSTORMS FOR THURSDAY.
&&
.AVIATION...
TAFS WILL BE DEPENDENT ONCE AGAIN ON EVENTUAL CONVECTIVE DEVELOPMENTS TODAY.
CONVECTIVE BASED MODELS SUGGEST ONSET OF STORMS COULD IMPACT SOME LOCATIONS
BY 14Z...PRIMARILY WESTERNMOST LOCATIONS LIKE KBTR AND KHUM...THOUGH ALL
TERMINALS SHOULD SEE SOME PERIODS OF TSRA/SHRA THROUGHOUT THE DAY. DOWN BURST
POTENTIAL WILL BE HIGH TODAY WITH GUST POTENTIAL 35-45 KT. EFFICIENT RAINFALL
PROCESS SHOULD ALSO LOWER VSBY TO VLIFR LEVELS AT TIMES DURING HEAVY RAINFALL.
OTHERWISE...VFR CONDITIONS SHOULD PREVAIL AFTER 16Z OUTSIDE
CONVECTION.
&&
.MARINE...
AN INTERESTING WAKE LOW PHENOMENA IMPACTED THE OFFSHORE WATERS
THIS MORNING...BUT THIS HAS SINCE WEAKENED. OVERALL...EXPECT TO
SEE AN ONSHORE FLOW OF 10 TO 15 KNOTS REMAIN OVER THE COASTAL
WATERS THROUGH FRIDAY. AS AN UPPER LEVEL LOW AND ASSOCIATED WEAK
SURFACE LOW AND FRONT MOVE THROUGH OVER THE WEEKEND...WINDS WILL
INCREASE INTO EXERCISE CAUTION RANGE SATURDAY AND REMAIN ELEVATED
INTO SUNDAY. SEAS WILL RESPOND AND INCREASE TO 3 TO 5 FEET IN THE
OFFSHORE WATERS. THE GRADIENT WILL EASE OVER THE AREA ON
MONDAY...ALLOWING FOR WEAKER AND MORE VARIABLE FLOW OF 10 KNOTS OR
LESS. SEAS WILL ALSO FALL BACK INTO THE 1 TO 3 FEET RANGE FOR
MONDAY AND TUESDAY.
&&
.DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING HEAVY RAINFALL/FLOODING POTENTIAL
ASSESSING SEVERE WEATHER THREAT THRU WEEKEND.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TONIGHT RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 78 65 79 66 / 80 60 70 50
BTR 79 66 81 67 / 80 60 70 50
ASD 78 67 80 68 / 70 70 70 60
MSY 78 69 80 69 / 70 70 70 60
GPT 77 68 78 69 / 70 70 70 70
PQL 78 67 79 69 / 70 70 70 70
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR LAZ040-046>050-
056>070-072.
GM...NONE.
MS...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR MSZ077-080>082.
GM...NONE.
&&
$$
32
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
217 PM EDT THU APR 16 2015
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING
SHOWERS THIS AFTERNOON INTO FRIDAY MORNING. HIGH PRESSURE WILL
BRING A DRY START TO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AREA OF SHOWERS HAS SPREAD ACROSS MUCH OF THE REGION AND WILL
CONTINUE TO MOVE AND DEVELOP NORTHEAST INTO THE EVENING. UPPER
LEVEL TROUGH MOVING INTO THE OHIO VALLEY THIS AFTERNOON WILL KEEP
SHOWER CHANCES IN THE LIKELY CATEGORY UNTIL THIS EVENING WHEN
UPPER TROUGH BEGINS TO SHEAR OUT AND A WEAK BOUNDARY APPROACHES
FROM THE GREAT LAKES. SHOWERS WILL DIMINISH FROM WEST TO EAST
OVERNIGHT AS DEEP MOISTURE IS TAKEN EAST OF THE RIDGES.
TEMPERATURES WILL NOT MOVE MUCH FROM CURRENT READINGS WHERE RAIN
HAS FALLEN. MIN TEMPS TONIGHT INTO THE 40S BUT STILL A BIT ABOVE
AVERAGE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE
SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE
COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO
REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY
AFTERNOON.
BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO
VALLEY SATURDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL
BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND
CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL
RETURN BEHIND THIS SYSTEM.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SHOWERS WILL CONTINUE TO BLOSSOM WITH HELP FROM A PASSING
SHORTWAVE THROUGH THIS AFTERNOON AND EVENING. A GRADUAL
DETERIORATION TO MVFR AND IFR CIGS IS EXPECTED OVERNIGHT AT MOST
PORTS AS THE WEAK FRONTAL BOUNDARY CROSSES. TRIED TO FOLLOW THE
SREF PROBABILITIES AND BUFKIT MOISTURE PROFILES WITH TIMING OF
RESTRICTIONS...AS THE NAM AND LAMP SEEM TO BE A BUT MORE
PESSIMISTIC AT THIS TIME. WHILE VERY BRIEF IFR VISIBILITY MAY BE
EXPECTED IN THE MORE INTENSE SHOWERS...OPTED TO NOT CARRY THIS AT
ANY PARTICULAR SITE AND WILL COVER WITH TEMPOS AS NEEDED.
A ESE TO WSW WIND SHIFT IS ANTICIPATED OVERNIGHT. GRADUAL
IMPROVEMENT BACK TO MVFR WILL OCCUR TOMORROW.
.OUTLOOK.../FRIDAY THROUGH TUESDAY/...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE
APPROACH OF LOW PRESSURE ON SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
124 PM EDT THU APR 16 2015
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING
SHOWERS THIS AFTERNOON INTO FRIDAY MORNING. HIGH PRESSURE WILL
BRING A DRY START TO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AREA OF SHOWERS HAS SPREAD ACROSS MUCH OF THE REGION AND WILL
CONTINUE TO MOVE AND DEVELOP NORTHEAST INTO THE EVENING. UPPER
LEVEL TROUGH MOVING INTO THE OHIO VALLEY THIS AFTERNOON WILL KEEP
SHOWER CHANCES IN THE LIKLEY CATAGORY UNTIL THIS EVENING WHEN
UPPER TROUGH BEGINS TO SHEAR OUT AND A WEAK BOUNDARY APPROACHES
FROM THE GREAT ALKES. SHOWERS WILL DIMINISH FROM WEST TO EAST
OVERNIGHT AS DEEP MOISTURE IS TAKEN EAST OF THE RIDGES.
TEMPERATURES WILL NOT MOVE MUCH FROM CURRENT READINGS WHERE RAIN
HAS FALLEN. MIN TEMPS TONIGHT INTO THE 40S BUT STILL A BIT ABOVE
AVERAGE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE
SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE
COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO
REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY
AFTERNOON.
BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO
VALLEY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL
BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND
CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL
RETURN BEHIND THIS SYSTEM.
&&
.AVIATION /17Z THURSDAY THROUGH MONDAY/...
LOCAL MVFR CONDITIONS IN SCATTERED SHOWERS THIS AFTERNOON.
INCREASING ESE TURNING SOUTH WINDS SHOULD PRECLUDE VISIBLITY
RESTRICTIONS...HOWEVER CIGS WILL TREND AT LEAST CLOSE TO IFR BY
TONIGHT AS LOW LEVELS BECOME SATURATED.
.OUTLOOK.../FRIDAY THROUGH MONDAY/... THE NEXT CHANCE FOR GENERAL
RESTRICTIONS IS EXPECTED WITH THE APPROACH OF LOW PRESSURE ON
SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1020 AM EDT THU APR 16 2015
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING
SHOWERS THIS AFTERNOON INTO FRIDAY MORNING. HIGH PRESSURE WILL
BRING A DRY START TO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONLY CHANGES WERE TO MAX TEMPS AND HOURLY TEMPS. WHERE SHOWERS
HAVE ARRIVED TEMPERATURES HAVE DROPPED OFF DUE TO WET
BULBING...WHILE AREAS NORTH AND EAST OF KPIT I-80 REMAIN WARMER
WITH SOME SUNSHINE.
PREVIOUS...
SHOWER CHANCES WILL INCREASE FROM WEST TO EAST AHEAD OF A
SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON. THINK
A SLOWER APPROACH TO BEGINNING THE SHOWERS IS THE WAY TO GO AS THE
MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO
A VERY DRY ATMOSPHERE. SHOWERS WILL OVERSPREAD THE ENTIRE AREA
THIS AFTERNOON AS THE WAVE MOVES THROUGH.
WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW
SEASONABLE LEVELS. SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY
MORNING AS THE SURFACE BOUNDARY SLOWLY MOVES THROUGH THE REGION.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
UPPER LEVEL SUPPORT WILL QUICKLY EXIT THE AREA...SO EXPECT THE
SHOWERS TO RAP UP IN THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE
COLD ADVECTION IS EXPECTED...SO TEMPERATURES WILL BE ABLE TO
REBOUND BACK TO...IF NOT WARMER THAN SEASONAL AVERAGES FRIDAY
AFTERNOON.
BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO
VALLEY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL
BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND
CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL
RETURN BEHIND THIS SYSTEM.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL VERY SLOWLY GIVE WAY TO LOCAL MVFR CONDITIONS
IN SCATTERED SHOWERS AS THEY ENCROACH ON THE REGION ESPECIALLY
THIS AFTERNOON. CONFIDENCE IS LOW ON THE TIMES OF THE LOW
DETERIORATION OF CIGS...HOWEVER VIRGA SHOULD GRADUALLY TURN INTO
LIGHT RAIN AS HIGHER DEWPOINTS ENCROACH. INCREASING ESE TURNING
SOUTH WINDS SHOULD PRECLUDE VISIBLITY RESTRICTIONS...HOWEVER CIGS
WILL TREND AT LEAST CLOSE TO IFR BY TONIGHT AS DEEPER MOISTURE
SLOWLY ENTERS THE REGION.FRIES
.OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE
APPROACH OF LOW PRESSURE ON SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
752 AM EDT THU APR 16 2015
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING
SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START
TO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO CHANGES NEEDED TO EARLY MORNING UPDATE
PREVIOUS...
SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD
OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON.
THINK A SLOWER APPROACH TO BEGINNING THE SHOWERS IS THE WAY TO GO AS
THE MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING
INTO A VERY DRY ATMOSPHERE. SHOWERS WILL OVERSPREAD THE ENTIRE
AREA THIS AFTERNOON AS THE WAVE MOVES THROUGH.
WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW
SEASONABLE LEVELS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE
BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT
WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN
THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS
EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF
NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON.
BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO
VALLEY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL
BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND
CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL
RETURN BEHIND THIS SYSTEM.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL VERY SLOWLY GIVE WAY TO LOCAL MVFR CONDITIONS
IN SCATTERED SHOWERS AS THEY ENCROACH ON THE REGION ESPECIALLY
THIS AFTERNOON. CONFIDENCE IS LOW ON THE TIMES OF THE LOW
DETERIORATION OF CIGS...HOWEVER VIRGA SHOULD GRADUALLY TURN INTO
LIGHT RAIN AS HIGHER DEWPOINTS ENCROACH. INCREASING ESE TURNING
SOUTH WINDS SHOULD PRECLUDE VISIBLITY RESTRICTIONS...HOWEVER CIGS
WILL TREND AT LEAST CLOSE TO IFR BY TONIGHT AS DEEPER MOISTURE
SLOWLY ENTERS THE REGION.FRIES
.OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE
APPROACH OF LOW PRESSURE ON SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
620 AM EDT THU APR 16 2015
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING
SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START
TO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD
OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON.
STILL SEEING SOME TIMING DIFFERENCES IN MODEL SOLUTIONS AS THE
MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO
A VERY DRY ATMOSPHERE. THINK A SLOWER APPROACH TO BEGINNING THE
SHOWERS IS THE WAY TO GO. SHOWERS WILL OVERSPREAD THE ENTIRE AREA
THIS AFTERNOON AS THE WAVE MOVES THROUGH.
WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW
SEASONABLE LEVELS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE
BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT
WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN
THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS
EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF
NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON.
BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO
VALLEY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL
BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND
CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL
RETURN BEHIND THIS SYSTEM.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL VERY SLOWLY GIVE WAY TO LOCAL MVFR CONDITIONS
IN SCATTERED SHOWERS AS THEY ENCROACH ON THE REGION ESPECIALLY
THIS AFTERNOON. CONFIDENCE IS LOW ON THE TIMES OF THE LOW
DETERIORATION OF CIGS...HOWEVER VIRGA SHOULD GRADUALLY TURN INTO
LIGHT RAIN AS HIGHER DEWPOINTS ENCROACH. INCREASING ESE TURNING
SOUTH WINDS SHOULD PRECLUDE VISIBLITY RESTRICTIONS...HOWEVER CIGS
WILL TREND AT LEAST CLOSE TO IFR BY TONIGHT AS DEEPER MOSITURE
SLOWLY ENTERS THE REGION. FRIES
.OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE
APPROACH OF LOW PRESSURE ON SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
405 AM EDT THU APR 16 2015
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING
SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START
TO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD
OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON.
STILL SEEING SOME TIMING DIFFERENCES IN MODEL SOLUTIONS AS THE
MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO
A VERY DRY ATMOSPHERE. THINK A SLOWER APPROACH TO BEGINNING THE
SHOWERS IS THE WAY TO GO. SHOWERS WILL OVERSPREAD THE ENTIRE AREA
THIS AFTERNOON AS THE WAVE MOVES THROUGH.
WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW
SEASONABLE LEVELS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE
BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT
WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN
THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS
EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF
NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON.
BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO
VALLEY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL
BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND
CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL
RETURN BEHIND THIS SYSTEM.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE OVERNIGHT. TERMINALS MAY SEE MVFR CIG
RESTRICTIONS BY TOMORROW EVENING WITH SCATTERED SHOWERS ACROSS
THE REGION.
.OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE
APPROACH OF LOW PRESSURE ON SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
105 AM EDT THU APR 16 2015
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE AND TRAILING COLD FRONT WILL BRING
SHOWERS TODAY THROUGH FRIDAY MORNING. A DRY AND COMFORTABLE START
TO THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
OVERNIGHT PERIOD IN GOOD SHAPE. JUST MADE MINOR ADJUSTMENTS TO THE
ONSET OF POPS AS DAWN APPROACHES. TEMPERATURES HAVE BEEN NUDGED
TOWARD THE LATEST LAMP NUMBERS.
SHOWER CHANCES WILL INCREASE FROM WEST TO EAST THIS MORNING AHEAD
OF A SHORTWAVE TROUGH THAT REACHES THE AREA LATE THIS AFTERNOON.
STILL SEEING SOME TIMING DIFFERENCES IN MODEL SOLUTIONS AS THE
MOISTURE ASSOCIATED WITH THE UPPER LEVEL WAVE WILL BE RUNNING INTO
A VERY DRY ATMOSPHERE. THINK A SLOWER APPROACH TO BEGINNING
SHOWERS IS THE WAY TO GO. SHOWERS WILL OVERSPREAD THE ENTIRE AREA
THIS AFTERNOON AS THE WAVE MOVES THROUGH.
WITH THE CLOUDS AND SHOWERS...TEMPERATURES WILL BE A BIT BELOW
SEASONABLE LEVELS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
SHOWERS CONTINUE OVERNIGHT AND INTO FRIDAY MORNING AS THE SURFACE
BOUNDARY SLOWLY MOVES THROUGH THE REGION. UPPER LEVEL SUPPORT
WILL QUICKLY EXIT THE AREA...SO EXPECT THE SHOWERS TO RAP UP IN
THE EAST FRIDAY MORNING. NO REAL DISCERNIBLE COLD ADVECTION IS
EXPECTED...SO TEMPERATURES WILL BE ABLE TO REBOUND BACK TO...IF
NOT WARMER THAN SEASONAL AVERAGES FRIDAY AFTERNOON.
BROAD SURFACE HIGH AND UPPER LEVEL RIDGE WILL BUILD INTO THE OHIO
VALLEY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS STILL SHOWING A LARGE AND SLOW MOVING SYSTEM THAT WILL
BRING AN EXTENDED PERIOD OF SHOWERS BEGINNING SUNDAY AND
CONTINUING INTO EARLY TUESDAY. DRY AND SEASONABLE WEATHER WILL
RETURN BEHIND THIS SYSTEM.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE OVERNIGHT. TERMINALS MAY SEE MVFR CIG
RESTRICTIONS BY TOMORROW EVENING WITH SCATTERED SHOWERS ACROSS
THE REGION.
.OUTLOOK.../TUESDAY NIGHT THROUGH SUNDAY/...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH THE
APPROACH OF LOW PRESSURE ON SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 PM EDT THU APR 16 2015
.UPDATE...
ISSUED AT 657 AM EDT THU APR 16 2015
DECIDED TO PUT SPRINKLES INTO FORECAST OVER EASTERN CWA /ISQ-ERY/
MID MORNING INTO EARLY AFTN AS BAND OF SHOWERS OVER LOWER MICHIGAN
CONTINUES TO LIFT NORTHWARD. EVEN THOUGH SHRA WILL BE RUNNING INTO
THE DRY AIRMASS OVER AREA AS SEEN ON 00Z APX AND DTX RAOBS...THINK
ENOUGH FOCUS FM SHORTWAVE AND MOISTURE TRANSPORT AT H85-H7 IS GOING
TO END UP STRONG/PERSISTENT ENOUGH TO OUTWEIGH THE LOW-LEVEL DRY
AIR. VARIOUS HIGH RES MODELS AND THE 06Z/07Z HRRR REFLECTIVITY
OUTPUT POINT TO AT LEAST A BRIEF PERIOD OF LGT RAIN/SPRINKLES.
BEEFED UP SKY COVER SOME MORE AS WELL. OTHER THAN TWEAKS FOR VERY
SHORT TERM TEMP/DWPNT TRENDS...NO OTHER CHANGES WERE NEEDED TO
FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 435 AM EDT THU APR 16 2015
SHORTWAVE RIDGING PERSISTS TODAY BTWN NORTHERN STREAM SHORTWAVE THAT
CROSSES MANITOBA/NORTHERN ONTARIO AND CUTOFF LOW OVER FOUR CORNERS
OF SW CONUS. WEAK AREAS OF VORTICITY LIFTING INTO THE RIDGE BRINGING
A PUSH OF MID-LEVEL MOISTURE ADVECTION AROUND H7. DECENT AREA OF
SHRA IS LIFTING NORTHWARD OVER WESTERN LOWER MICHIGAN ON NORTH EDGE
OF MOISTURE TRANSPORT AT H85-H7 AND THIS COULD BRING VIRGA OR A FEW
SPRINKLES TO EASTERN CWA...POSSIBLY AS FAR WEST AS KESC PER HRRR
MODEL LATE MORNING INTO EARLY AFTN. ELSEWHERE WILL CERTAINLY BE MORE
CLOUDS THAN LAST COUPLE DAYS AS CIRRUS AND MORE PRONOUNCED AREA OF
AC/AS OVER MN SLIDES IN FOR THE AFTN. EVEN SO THOUGH...WARM START
SHOULD STILL ALLOW MAX TEMPS TO REACH WELL INTO THE 60S. RH VALUES A
BIT HIGHER THAN BONE DRY CONDITIONS SEEN TUE/WED WHERE RH BOTTOMED
OUT AROUND 10 PCT OVER INTERIOR WEST. FOR TODAY IN THOSE AREAS...
EXPECT MAINLY 18-25 PCT RANGE AT THE LOW-END. WINDS LESS THAN 10 MPH
MOST AREAS WITH LOCAL LAKE BREEZES CNTRL. OVERALL APPEARS TO NOT BE
AS MUCH OF ISSUE WITH FIRE WEATHER TODAY COMPARED TO TUE OR WED.
NORTHERN STREAM SHORTWAVE CROSSES NORTHERN ONTARIO TONIGHT WITH
TAIL OF ENHANCED CLOUD GRAZING CWA...ALONG WITH THE PASSAGE OF SFC
TROUGH...MORE OF A WIND SHIFT FM SW TO NW LATE TONIGHT. SINCE 1000-
700MB LAPSE RATES ARE HIGH...OVER 7C/KM BY LATE AFTN...AND FORCING
IS MOVING THROUGH WITH SUFFICIENT MOISTURE ALOFT...THINK THERE IS A
CHANCE OF SPRINKLES/VIRGA THIS EVENING AS THE FORCING MOVES
THROUGH...PERHAPS SIMILAR TO WHAT OCCURRED MON AFTN/EVENING. THAT
SAID...WINDS IN MIXED LAYER THIS EVENING DO INCREASE BY 03Z WITH 25-
30 KTS AT TOP PARTS OF THE MIXED LAYER. SO...FEASIBLE THAT GUSTY
WINDS COULD OCCUR IN THE VCNTY OF ANY WELL DEVELOPED CU OR
VIRGA/SPRINKLES. ALL FORCING IS OUT OF HERE BY MIDNIGHT AND SCT-BKN
CLOUDS SHOULD EXIT OVERNIGHT. SKIES WILL BE MAINLY CLEAR BY DAYBREAK
ON FRIDAY. LOWS TONIGHT SHOULD REMAIN ABOVE FREEZING ALL AREAS GIVEN
THE WINDS AND CLOUDS MOST OF THE NIGHT AND LACK OF COLD AIR BEHIND
THE TROUGH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT WED APR 15 2015
AFTER A QUIET AND GENERALLY WARM REST OF THIS WEEK...SIGNIFICANT
AMPLIFICATION OF THE FLOW IS EXPECTED THIS WEEKEND AND EARLY NEXT
WEEK AS A SHARP RIDGE BUILDS THRU WRN CANADA. THIS WILL FORCE A DEEP
TROF TO DEVELOP DOWNSTREAM WITH AXIS ROUGHLY OVER THE MISSISSIPPI
VALLEY BY MON. TYPICAL FOR THIS TIME OF YEAR...CLOSED LOWS
FREQUENTLY DEVELOP...AND THIS TROF WILL QUICKLY EVOLVE IN THAT
DIRECTION AS MAJORITY OF GUIDANCE INCLUDING GFS/GEM ENSEMBLES SHOW
EVOLUTION INTO A LARGE/COLD MID-LEVEL LOW OVER THE VICINITY OF THE
UPPER GREAT LAKES. MAY BE DIFFICULT TO DISLODGE THE LOW NEXT WEEK
ONCE IT DEVELOPS. SO...AFTER A WARM/DRY REST OF THIS WEEK...NEXT
WEEK WILL BE COLD AND GENERALLY UNSETTLED WITH PERIODIC CHANCES OF
SNOW AND RAIN SHOWERS. FROM A PCPN PERSPECTIVE...THE BIGGEST
CHALLENGE IS HOW THE SHARP PATTERN AMPLIFICATION INTERACTS WITH WHAT
IS CURRENTLY AN IMPRESSIVE LOOKING TROF CLOSING OFF OVER UT/CO.
MEDIUM RANGE GUIDANCE TODAY IS IN MUCH BETTER AGREEMENT IN SHOWING
THE AMPLIFICATION OF THE FLOW PICKING UP THE MID-LEVEL LOW AND
FORCING THE OPENED UP SYSTEM/REMNANT ENERGY NE INTO THE GREAT LAKES
REGION. RANGE OF POSSIBILITIES STILL INCLUDE A SIGNIFICANT RAIN
EVENT TO A RAIN CHANGING TO ACCUMULATING SNOW EVENT TO MINIMAL PCPN
IF THE SRN ENERGY DOES NOT LIFT FAR ENOUGH N AND W WITHIN THE
AMPLIFYING PATTERN. OPERATIONAL MEDIUM RANGE MODELS WEAKEN THE
ENERGY DRAMATICALLY AS IT LIFTS NE (WILL BE INTERESTING TO SEE IF
THAT ACTUALLY HAPPENS)...SO THE LOWEST PROBABILITY OUTCOME RIGHT NOW
IS ONE THAT BRINGS A SIGNIFICANT PCPN PRODUCING SYSTEM WITH A
PROMINENT DEFORMATION PCPN SHIELD INTO THE UPPER LAKES EARLY NEXT
WEEK. THAT SAID...THERE HAVE BEEN AND THERE STILL ARE SOME GFS/GEM
ENSEMBLES THAT DO SHOW SUCH A SCENARIO...SO IT CAN`T BE RULED OUT.
BEGINNING THU NIGHT...TAIL END OF SHORTWAVE TRACKING FROM HUDSON BAY
INTO QUEBEC WILL PASS ACROSS THE AREA THU NIGHT. FORCING FROM THE
RIGHT ENTRANCE OF AN UPPER JET STREAK AND MAIN DEEP LAYER QVECTOR
CONVERGENCE...WEAK AT THAT...PASS N OF THE AREA...SUPPORTING BEST
CHC OF -SHRA N OF HERE. ACROSS UPPER MI...VERY WEAK FORCING/WEAK
FRONTAL BOUNDARY AND WEAK MOISTURE TRANSPORT ALL SUGGEST PROSPECT OF
ANY PCPN IS VERY LIMITED AS SHORTWAVE PASSES. THUS...WILL RETAIN DRY
FCST FOR THU NIGHT.
IN THE MAIN FLOW TO THE N...ANOTHER SHORTWAVE IS FCST TO TRACK FROM
THE CANADIAN ROCKIES THU AFTN TO NRN ONTARIO FRI. MODELS HAVE
TRENDED TO MUCH BETTER AGREEMENT ON THIS WAVE WITH GEM/GFS/NAM
MOVING TO THE ECMWF SCENARIO WHICH HAS BEEN FARTHER N THAN THOSE
MODELS FOR SEVERAL RUNS. WITH THE TRACK OF THE SHORTWAVE JUST N OF
LAKE SUPERIOR...BEST FORCING AND POTENTIAL FOR PCPN WILL PASS BY TO
THE N. REMOVED SCHC POPS FROM INHERITED FCST IN FAVOR OF DRY
WEATHER. EXPECT HIGH TEMPS FRI IN THE 60S AWAY FROM LAKE MODERATION.
A FEW SPOTS MAY REACH 70F. INTERIOR RH SHOULD FALL TO 25-30PCT...
AND WINDS MAY BE A LITTLE GUSTY TO 15-20MPH AT TIMES...KEEPING FIRE
WX A CONCERN.
IN THE WAKE OF THE SHORTWAVE...HIGH PRES BUILDS INTO THE AREA FOR
SAT. WITH THE HIGH ENDING UP OVER LAKE SUPERIOR IN THE AFTN...IT
WILL BE A MUCH COOLER DAY NEAR LAKE SUPERIOR...ESPECIALLY FROM THE
KEWEENAW EASTWARD. RIGHT ALONG THE SHORE...TEMPS SHOULDN`T GET OUT
OF THE 30S. IN THE INTERIOR W HALF...TEMPS SHOULD RISE TO AROUND 60F
UNDER SUNNY SKIES.
SUN/MON...WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH OF CURRENT
AND RECENT MEDIUM RANGE GUIDANCE FOR THE EVOLUTION OF THE SRN
ROCKIES ENERGY INTO THE GREAT LAKES AHEAD OF THE TROF AMPLIFICATION
OCCURRING INTO THE PLAINS/MISSISSIPPI VALLEY. IT APPEARS THERE MAY
END UP BEING TWO SURGES OF PCPN OR SFC LOW PRES WAVES...ONE
ASSOCIATED WITH LEAD ENERGY SWINGING UP FROM MEXICO AND A SECOND
ASSOCIATED WITH THE MAIN REMNANT OF THE ROCKIES MID LEVEL LOW.
LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN SPREADING INTO UPPER MI SUN
AND THEN CONTINUE INTO MON. AIR MASS SHOULD COOL ENOUGH TO ALLOW
SOME SNOW TO BEGIN MIXING WITH THE RAIN OVER THE W ON MON. PTYPE
WILL THEN BECOME ALL SNOW ACROSS THE FCST AREA MON NIGHT FOR
WHATEVER PCPN LINGERS.
TUE/WED...LARGE/COLD MID-LEVEL LOW WILL HAVE DEVELOPED AND WILL BE
CENTERED IN THE VCNTY OF THE UPPER GREAT LAKES. COLD AIR
ALOFT/SPRING DAYTIME HEATING AND POTENTIAL OF SHORTWAVES ROTATING
THRU THE AREA WITHIN THE LARGE MID-LEVEL LOW CIRCULATION SUGGEST AT
LEAST SCT SHOWERY PCPN (MOSTLY SNOW BUT SOME RAIN AS WELL DURING
PEAK HEATING) BOTH DAYS WITH BEST COVERAGE IN THE AFTN INLAND FROM
LAKE SUPERIOR WHERE HEATING IS BEST. HIGH TEMPS BOTH DAYS SHOULD BE
IN THE MID 30S TO MID 40S...WARMEST SCNTRL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 125 PM EDT THU APR 16 2015
VFR CONDITIONS WILL CONTINUE FOR THIS FORECAST PERIOD. IT IS
POSSIBLE THERE COULD BE A LIGHT SHOWER OR SPRINKLE AROUND EARLY THIS
EVENING AHEAD OF THE FRONT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 435 AM EDT THU APR 16 2015
NO WIDESPREAD GALES ARE EXPECTED THROUGH THE FORECAST PERIOD...BUT
THERE WILL BE A FEW PERIODS OF STRONGER WINDS STARTING THIS WEEKEND.
WINDS EXPECTED TO REMAIN AT OR BLO 20 KTS THROUGH FRIDAY NIGHT AS
PRESSURE GRADIENT IS WEAK. HIGH PRESSURE MOVING ACROSS ON SATURDAY
WITH LOW PRESSURE FOLLOWING OVER SCNTRL CANADA ON SUNDAY WILL RESULT
IN SETUP FOR STRONGER EAST-NORTHEAST WINDS TO 30 KTS OVER WESTERN LK
SUPERIOR SATURDAY AND SATURDAY NIGHT. STRONGEST WINDS WILL BE TOWARD
HEAD OF LK SUPERIOR NEAR DULUTH AND SUPERIOR. BY SUNDAY...AS THE LOW
PRESSURE SYSTEM APPROACHES...SOUTHEAST WINDS TO 30 KTS WILL BE
POSSIBLE OVER EASTERN HALF OF LK SUPERIOR WHILE WINDS DIMINISH IN
THE WEST. THE LOW CROSSES THE UPPER GREAT LAKES BY MONDAY WHILE
MERGING WITH ANOTHER LOW LIFTING IN FM THE CENTRAL PLAINS. EXPECT
WEST WINDS UP TO 30 KTS OVER MUCH OF THE LAKE LATER MONDAY INTO
TUESDAY IN WAKE OF THIS COMBINED LOW AS IT MOVES TO THE LOWER GREAT
LAKES.
&&
.HYDROLOGY...
ISSUED AT 332 PM EDT WED APR 15 2015
SEEMS THAT WITHOUT ANY SIGNIFICANT ADDITIONAL PRECIPITATION ADDED TO
THE ONGOING SNOWMELT...AT LEAST FOR THE REST OF THIS WEEK...MAINLY
LOOKING AT A FEW BANKFULL ISSUES ON SOME RIVERS WITH CONTINUATION OF
LOW-END ADVISORIES. BELOW NORMAL TEMPERATURES ARE EXPECTED MONDAY
THROUGH MUCH OF NEXT WEEK...WHICH WILL LIMIT MELTING OF ANY
REMAINING SNOW PACK AND REDUCE RIVER LEVELS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...TITUS
MARINE...JLA
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1205 PM EDT THU APR 16 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 310 AM EDT THU APR 16 2015
LIGHT RAIN IS LIKELY TODAY ACROSS MUCH OF SOUTHWEST LOWER MICHIGAN
AS WEAK LOW PRESSURE MOVES NORTH FROM THE GULF. THE SHOWERS WILL
DIMINISH TONIGHT LEADING TO A DRY FRIDAY AND SATURDAY. RAIN IS BACK
IN THE PICTURE LATE IN THE WEEKEND AND EARLY NEXT WEEK AS A STRONGER
LOW MOVES EAST FROM THE PLAINS ACROSS THE GREAT LAKES.
TODAY WILL BE A BIT COOLER THAN WEDNESDAY; WE/LL SEE HIGHS IN THE
50S. TEMPERATURES WILL CLIMB TO AROUND 70 FRIDAY AND SATURDAY BEFORE
COOLER WEATHER DEVELOPS EARLY NEXT WEEK. MUCH OF NEXT WEEK WILL SEE
HIGHS ONLY AROUND 50.
&&
.UPDATE...
ISSUED AT 856 AM EDT THU APR 16 2015
I DID A QUICK UPDATE TO THE POP AND WEATHER GRIDS TO BETTER
REFLECT THE CURRENT RADAR TRENDS. THAT MEANS I INCREASED THE POP
TO NEAR 100 PCT OVER OUR NW CWA AND I HAVE AN AREA OF LOW POP
SOUTHWEST OF GRR (IT IS REALLY THERE) THAT MOVES NORTH WITH TIME.
THE ENTIRE AREA OF SHOWERS SHOULD BE MOSTLY OUT OF OUR CWA BY
MID AFTERNOON AS DRIER AIR MOVES IN AT MID LEVELS. THIS IDEA IS
MOSTLY BASED ON USING THE RAP MODEL LIFT IN THE DGZ WHERE THE AIR
IN THAT LAYER IS SATURATED. AT 8 AM THE AREA OF BEST LIFT IS NEAR
AND WEST OF US-131. BY 2 PM IT IS MOSTLY EAST OF I-75 BUT THERE IS
A SMALL AREA OF STRONG LIFT JUST SOUTH OF GRR AT THAT TIME WHICH
LIFTS TO NEAR LANSING BY 5 PM. THAT WILL HAVE TO BE WATCHED TO SEE
OF AN AREA OF SIGNIFICANT SHOWERS DOES DEVELOP THERE. I STILL EXPECT
NO THUNDERSTORM ACTIVITY TODAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 310 AM EDT THU APR 16 2015
FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY. OVERALL...THE
FORECAST IS LARGELY ON TRACK ALTHOUGH QPF HAS BEEN TRIMMED A BIT.
00Z SOUNDING AT DTX WAS EXTREMELY DRY BELOW 450 MB AND EXPLAINS WHY
WE HAVEN/T SEEN MUCH RAIN AT THE SFC DESPITE ECHOS ACROSS THE LAKE
SHORE. THE SFC WAVE OF LOW PRESSURE TO THE SOUTH WILL MOVE OVER THE
CWA TODAY AND WE SHOULD SEE THE LOWER LEVELS OF THE ATM MOISTEN AND
RAIN TO DEVELOP. KGRR-88D SHOWS ECHO INTENSITY INCREASING A BIT AS
PCPN CONTINUES TO MOVE NORTH FROM INDIANA. SHORT RANGE NWP SHOWED
THE AREA OF THETA-E DECREASING WITH HEIGHT REMAINING SOUTH OF THE
CWA SO WE OPTED TO GO WITH NO THUNDER IN THE GRIDS TODAY. PCPN WILL
BEGIN TO MOVE EAST THIS AFTERNOON AND END EARLY IN THE EVENING. THIS
WILL LEAD TO A COUPLE OF DRY DAYS FRIDAY AND SATURDAY AS HIGH
PRESSURE NOSES IN FROM ONTARIO.
TEMPS WILL BE HELD DOWN A BIT BY THE SHOWERS TODAY AND WE`LL GO WITH
HIGHS IN THE MID TO UPPER 50S. UPPER HEIGHT RISES ASSOCIATED WITH
THE RIDGE WILL RESULT IN TEMPS AROUND 10 DEGREES WARMER FRIDAY AND
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 AM EDT THU APR 16 2015
MODEL GUIDANCE REMAINS CONSISTENT IN SHOWING RAIN MOVING IN ON
SUNDAY WITH THE BEST CHANCE FOR WET WEATHER SUNDAY AFTERNOON AND
EVENING AS A SFC LOW AND UPPER TROUGH AXIS MOVES OVER LOWER
MICHIGAN. THE LOW CUTS OFF AND BECOMES VERTICALLY STACKED NORTH OF
LAKE SUPERIOR ON MONDAY WITH VORT ENERGY ROTATING THROUGH LOWER
MICHIGAN ON TUESDAY AND WEDNESDAY. GIVEN WET BULB ZERO HEIGHTS
CRASHING TO NEAR THE SFC...DO NOT BE SURPRISED TO SEE SOME SNOW
ACROSS AT LEAST THE NORTHERN ZONES TUESDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1205 PM EDT THU APR 16 2015
A MIX OF MVFR AND VFR CONDITIONS WILL CONTINUE THIS AFTERNOON DUE TO
AREAS OF LOW CLOUD COVER. LINGERING LIGHT RAIN SHOWERS AND SPRINKLES
WILL GRADUALLY TAPER OFF THIS AFTERNOON. CONDITIONS SHOULD IMPROVE
TO MAINLY VFR THIS EVENING BUT THE COMBINATION OF PARTIAL CLEARING
AND LIGHT WINDS IN CONJUNCTION WITH LINGERING BOUNDARY LAYER
MOISTURE FROM RAINFALL TODAY WILL RESULT IN POTENTIAL FOR PATCHY FOG
TO DEVELOP OVERNIGHT. ANY FOG SHOULD DISSIPATE BY MID MORNING FRIDAY
WITH VFR CONDITIONS TO FOLLOW FOR THE REST OF THE DAY.
&&
.MARINE...
ISSUED AT 310 AM EDT THU APR 16 2015
EAST WINDS 5 TO 15 KNOTS WILL NOT BE HAZARDOUS TO SMALL CRAFT TODAY.
&&
.HYDROLOGY...
ISSUED AT 1123 AM EDT THU APR 16 2015
THE LONE ADVISORY AT MAPLE RAPIDS CONTINUES TO SHOW IMPROVEMENT.
LIGHTER PRECIPITATION TODAY SHOULD NOT HAVE MUCH OF AN AFFECT ON
THE DROP THAT IS BEING EXPERIENCED. WE SHOULD SEE LEVELS DROP BELOW
ADVISORY CRITERIA LATE THIS EVENING.
BEYOND TWO DRY DAYS...FRIDAY AND SATURDAY...THE PATTERN GETS A BIT
ACTIVE AGAIN. WE COULD SEE SOME BENEFICIAL PRECIPITATION BETWEEN
SUNDAY AND TUESDAY. TOTAL AMOUNTS OVER THE NEXT 7 DAYS ARE NOT TOO
HEAVY. SOME MINOR FLUCTUATIONS MAY RESULT ON AREA RIVERS EARLY
NEXT WEEK...BUT AT THIS POINT I DO NOT SEE ANY REAL CAUSE FOR
CONCERN THROUGH THE PERIOD.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...OSTUNO
AVIATION...LAURENS
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1123 AM EDT THU APR 16 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 310 AM EDT THU APR 16 2015
LIGHT RAIN IS LIKELY TODAY ACROSS MUCH OF SOUTHWEST LOWER MICHIGAN
AS WEAK LOW PRESSURE MOVES NORTH FROM THE GULF. THE SHOWERS WILL
DIMINISH TONIGHT LEADING TO A DRY FRIDAY AND SATURDAY. RAIN IS BACK
IN THE PICTURE LATE IN THE WEEKEND AND EARLY NEXT WEEK AS A STRONGER
LOW MOVES EAST FROM THE PLAINS ACROSS THE GREAT LAKES.
TODAY WILL BE A BIT COOLER THAN WEDNESDAY; WE/LL SEE HIGHS IN THE
50S. TEMPERATURES WILL CLIMB TO AROUND 70 FRIDAY AND SATURDAY BEFORE
COOLER WEATHER DEVELOPS EARLY NEXT WEEK. MUCH OF NEXT WEEK WILL SEE
HIGHS ONLY AROUND 50.
&&
.UPDATE...
ISSUED AT 856 AM EDT THU APR 16 2015
I DID A QUICK UPDATE TO THE POP AND WEATHER GRIDS TO BETTER
REFLECT THE CURRENT RADAR TRENDS. THAT MEANS I INCREASED THE POP
TO NEAR 100 PCT OVER OUR NW CWA AND I HAVE AN AREA OF LOW POP
SOUTHWEST OF GRR (IT IS REALLY THERE) THAT MOVES NORTH WITH TIME.
THE ENTIRE AREA OF SHOWERS SHOULD BE MOSTLY OUT OF OUR CWA BY
MID AFTERNOON AS DRIER AIR MOVES IN AT MID LEVELS. THIS IDEA IS
MOSTLY BASED ON USING THE RAP MODEL LIFT IN THE DGZ WHERE THE AIR
IN THAT LAYER IS SATURATED. AT 8 AM THE AREA OF BEST LIFT IS NEAR
AND WEST OF US-131. BY 2 PM IT IS MOSTLY EAST OF I-75 BUT THERE IS
A SMALL AREA OF STRONG LIFT JUST SOUTH OF GRR AT THAT TIME WHICH
LIFTS TO NEAR LANSING BY 5 PM. THAT WILL HAVE TO BE WATCHED TO SEE
OF AN AREA OF SIGNIFICANT SHOWERS DOES DEVELOP THERE. I STILL EXPECT
NO THUNDERSTORM ACTIVITY TODAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 310 AM EDT THU APR 16 2015
FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY. OVERALL...THE
FORECAST IS LARGELY ON TRACK ALTHOUGH QPF HAS BEEN TRIMMED A BIT.
00Z SOUNDING AT DTX WAS EXTREMELY DRY BELOW 450 MB AND EXPLAINS WHY
WE HAVEN/T SEEN MUCH RAIN AT THE SFC DESPITE ECHOS ACROSS THE LAKE
SHORE. THE SFC WAVE OF LOW PRESSURE TO THE SOUTH WILL MOVE OVER THE
CWA TODAY AND WE SHOULD SEE THE LOWER LEVELS OF THE ATM MOISTEN AND
RAIN TO DEVELOP. KGRR-88D SHOWS ECHO INTENSITY INCREASING A BIT AS
PCPN CONTINUES TO MOVE NORTH FROM INDIANA. SHORT RANGE NWP SHOWED
THE AREA OF THETA-E DECREASING WITH HEIGHT REMAINING SOUTH OF THE
CWA SO WE OPTED TO GO WITH NO THUNDER IN THE GRIDS TODAY. PCPN WILL
BEGIN TO MOVE EAST THIS AFTERNOON AND END EARLY IN THE EVENING. THIS
WILL LEAD TO A COUPLE OF DRY DAYS FRIDAY AND SATURDAY AS HIGH
PRESSURE NOSES IN FROM ONTARIO.
TEMPS WILL BE HELD DOWN A BIT BY THE SHOWERS TODAY AND WE`LL GO WITH
HIGHS IN THE MID TO UPPER 50S. UPPER HEIGHT RISES ASSOCIATED WITH
THE RIDGE WILL RESULT IN TEMPS AROUND 10 DEGREES WARMER FRIDAY AND
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 AM EDT THU APR 16 2015
MODEL GUIDANCE REMAINS CONSISTENT IN SHOWING RAIN MOVING IN ON
SUNDAY WITH THE BEST CHANCE FOR WET WEATHER SUNDAY AFTERNOON AND
EVENING AS A SFC LOW AND UPPER TROUGH AXIS MOVES OVER LOWER
MICHIGAN. THE LOW CUTS OFF AND BECOMES VERTICALLY STACKED NORTH OF
LAKE SUPERIOR ON MONDAY WITH VORT ENERGY ROTATING THROUGH LOWER
MICHIGAN ON TUESDAY AND WEDNESDAY. GIVEN WET BULB ZERO HEIGHTS
CRASHING TO NEAR THE SFC...DO NOT BE SURPRISED TO SEE SOME SNOW
ACROSS AT LEAST THE NORTHERN ZONES TUESDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 736 AM EDT THU APR 16 2015
MVFR CONDITIONS WILL BECOME MORE WIDESPREAD TODAY AS SCATTERED SHOWERS
CONTINUE BUT THERE SHOULD FEW IF ANY AREAS OF IFR THROUGH TONIGHT.
WINDS WILL BE SOUTHEAST TODAY AOB 10 KNOTS THEN GO WEST BY THIS
EVENING AND DECREASE TO ABOUT 5 KNOTS.
&&
.MARINE...
ISSUED AT 310 AM EDT THU APR 16 2015
EAST WINDS 5 TO 15 KNOTS WILL NOT BE HAZARDOUS TO SMALL CRAFT TODAY.
&&
.HYDROLOGY...
ISSUED AT 1123 AM EDT THU APR 16 2015
THE LONE ADVISORY AT MAPLE RAPIDS CONTINUES TO SHOW IMPROVEMENT.
LIGHTER PRECIPITATION TODAY SHOULD NOT HAVE MUCH OF AN AFFECT ON
THE DROP THAT IS BEING EXPERIENCED. WE SHOULD SEE LEVELS DROP BELOW
ADVISORY CRITERIA LATE THIS EVENING.
BEYOND TWO DRY DAYS...FRIDAY AND SATURDAY...THE PATTERN GETS A BIT
ACTIVE AGAIN. WE COULD SEE SOME BENEFICIAL PRECIPITATION BETWEEN
SUNDAY AND TUESDAY. TOTAL AMOUNTS OVER THE NEXT 7 DAYS ARE NOT TOO
HEAVY. SOME MINOR FLUCTUATIONS MAY RESULT ON AREA RIVERS EARLY
NEXT WEEK...BUT AT THIS POINT I DO NOT SEE ANY REAL CAUSE FOR
CONCERN THROUGH THE PERIOD.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
856 AM EDT THU APR 16 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 310 AM EDT THU APR 16 2015
LIGHT RAIN IS LIKELY TODAY ACROSS MUCH OF SOUTHWEST LOWER MICHIGAN
AS WEAK LOW PRESSURE MOVES NORTH FROM THE GULF. THE SHOWERS WILL
DIMINISH TONIGHT LEADING TO A DRY FRIDAY AND SATURDAY. RAIN IS BACK
IN THE PICTURE LATE IN THE WEEKEND AND EARLY NEXT WEEK AS A STRONGER
LOW MOVES EAST FROM THE PLAINS ACROSS THE GREAT LAKES.
TODAY WILL BE A BIT COOLER THAN WEDNESDAY; WE/LL SEE HIGHS IN THE
50S. TEMPERATURES WILL CLIMB TO AROUND 70 FRIDAY AND SATURDAY BEFORE
COOLER WEATHER DEVELOPS EARLY NEXT WEEK. MUCH OF NEXT WEEK WILL SEE
HIGHS ONLY AROUND 50.
&&
.UPDATE...
ISSUED AT 856 AM EDT THU APR 16 2015
I DID A QUICK UPDATE TO THE POP AND WEATHER GRIDS TO BETTER
REFLECT THE CURRENT RADAR TRENDS. THAT MEANS I INCREASED THE POP
TO NEAR 100 PCT OVER OUR NW CWA AND I HAVE AN AREA OF LOW POP
SOUTHWEST OF GRR (IT IS REALLY THERE) THAT MOVES NORTH WITH TIME.
THE ENTIRE AREA OF SHOWERS SHOULD BE MOSTLY OUT OF OUR CWA BY
MID AFTERNOON AS DRIER AIR MOVES IN AT MID LEVELS. THIS IDEA IS
MOSTLY BASED ON USING THE RAP MODEL LIFT IN THE DGZ WHERE THE AIR
IN THAT LAYER IS SATURATED. AT 8 AM THE AREA OF BEST LIFT IS NEAR
AND WEST OF US-131. BY 2 PM IT IS MOSTLY EAST OF I-75 BUT THERE IS
A SMALL AREA OF STRONG LIFT JUST SOUTH OF GRR AT THAT TIME WHICH
LIFTS TO NEAR LANSING BY 5 PM. THAT WILL HAVE TO BE WATCHED TO SEE
OF AN AREA OF SIGNIFICANT SHOWERS DOES DEVELOP THERE. I STILL EXPECT
NO THUNDERSTORM ACTIVITY TODAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 310 AM EDT THU APR 16 2015
FORECAST CONCERNS DEAL WITH PCPN TRENDS TODAY. OVERALL...THE
FORECAST IS LARGELY ON TRACK ALTHOUGH QPF HAS BEEN TRIMMED A BIT.
00Z SOUNDING AT DTX WAS EXTREMELY DRY BELOW 450 MB AND EXPLAINS WHY
WE HAVEN/T SEEN MUCH RAIN AT THE SFC DESPITE ECHOS ACROSS THE LAKE
SHORE. THE SFC WAVE OF LOW PRESSURE TO THE SOUTH WILL MOVE OVER THE
CWA TODAY AND WE SHOULD SEE THE LOWER LEVELS OF THE ATM MOISTEN AND
RAIN TO DEVELOP. KGRR-88D SHOWS ECHO INTENSITY INCREASING A BIT AS
PCPN CONTINUES TO MOVE NORTH FROM INDIANA. SHORT RANGE NWP SHOWED
THE AREA OF THETA-E DECREASING WITH HEIGHT REMAINING SOUTH OF THE
CWA SO WE OPTED TO GO WITH NO THUNDER IN THE GRIDS TODAY. PCPN WILL
BEGIN TO MOVE EAST THIS AFTERNOON AND END EARLY IN THE EVENING. THIS
WILL LEAD TO A COUPLE OF DRY DAYS FRIDAY AND SATURDAY AS HIGH
PRESSURE NOSES IN FROM ONTARIO.
TEMPS WILL BE HELD DOWN A BIT BY THE SHOWERS TODAY AND WE`LL GO WITH
HIGHS IN THE MID TO UPPER 50S. UPPER HEIGHT RISES ASSOCIATED WITH
THE RIDGE WILL RESULT IN TEMPS AROUND 10 DEGREES WARMER FRIDAY AND
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 AM EDT THU APR 16 2015
MODEL GUIDANCE REMAINS CONSISTENT IN SHOWING RAIN MOVING IN ON
SUNDAY WITH THE BEST CHANCE FOR WET WEATHER SUNDAY AFTERNOON AND
EVENING AS A SFC LOW AND UPPER TROUGH AXIS MOVES OVER LOWER
MICHIGAN. THE LOW CUTS OFF AND BECOMES VERTICALLY STACKED NORTH OF
LAKE SUPERIOR ON MONDAY WITH VORT ENERGY ROTATING THROUGH LOWER
MICHIGAN ON TUESDAY AND WEDNESDAY. GIVEN WET BULB ZERO HEIGHTS
CRASHING TO NEAR THE SFC...DO NOT BE SURPRISED TO SEE SOME SNOW
ACROSS AT LEAST THE NORTHERN ZONES TUESDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 736 AM EDT THU APR 16 2015
MVFR CONDITIONS WILL BECOME MORE WIDESPREAD TODAY AS SCATTERED SHOWERS
CONTINUE BUT THERE SHOULD FEW IF ANY AREAS OF IFR THROUGH TONIGHT.
WINDS WILL BE SOUTHEAST TODAY AOB 10 KNOTS THEN GO WEST BY THIS
EVENING AND DECREASE TO ABOUT 5 KNOTS.
&&
.MARINE...
ISSUED AT 310 AM EDT THU APR 16 2015
EAST WINDS 5 TO 15 KNOTS WILL NOT BE HAZARDOUS TO SMALL CRAFT TODAY.
&&
.HYDROLOGY...
ISSUED AT 310 AM EDT THU APR 16 2015
AROUND A TENTH OF AN INCH OF RAIN IS POSSIBLE TODAY. THIS WILL HAVE
A NEGLIGIBLE EFFECT ON AREA RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...04
MARINE...04
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 AM EDT THU APR 16 2015
.UPDATE...
ISSUED AT 657 AM EDT THU APR 16 2015
DECIDED TO PUT SPRINKLES INTO FORECAST OVER EASTERN CWA /ISQ-ERY/
MID MORNING INTO EARLY AFTN AS BAND OF SHOWERS OVER LOWER MICHIGAN
CONTINUES TO LIFT NORTHWARD. EVEN THOUGH SHRA WILL BE RUNNING INTO
THE DRY AIRMASS OVER AREA AS SEEN ON 00Z APX AND DTX RAOBS...THINK
ENOUGH FOCUS FM SHORTWAVE AND MOISTURE TRANSPORT AT H85-H7 IS GOING
TO END UP STRONG/PERSISTENT ENOUGH TO OUTWEIGH THE LOW-LEVEL DRY
AIR. VARIOUS HIGH RES MODELS AND THE 06Z/07Z HRRR REFLECTIVITY
OUTPUT POINT TO AT LEAST A BRIEF PERIOD OF LGT RAIN/SPRINKLES.
BEEFED UP SKY COVER SOME MORE AS WELL. OTHER THAN TWEAKS FOR VERY
SHORT TERM TEMP/DWPNT TRENDS...NO OTHER CHANGES WERE NEEDED TO
FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 435 AM EDT THU APR 16 2015
SHORTWAVE RIDGING PERSISTS TODAY BTWN NORTHERN STREAM SHORTWAVE THAT
CROSSES MANITOBA/NORTHERN ONTARIO AND CUTOFF LOW OVER FOUR CORNERS
OF SW CONUS. WEAK AREAS OF VORTICITY LIFTING INTO THE RIDGE BRINGING
A PUSH OF MID-LEVEL MOISTURE ADVECTION AROUND H7. DECENT AREA OF
SHRA IS LIFTING NORTHWARD OVER WESTERN LOWER MICHIGAN ON NORTH EDGE
OF MOISTURE TRANSPORT AT H85-H7 AND THIS COULD BRING VIRGA OR A FEW
SPRINKLES TO EASTERN CWA...POSSIBLY AS FAR WEST AS KESC PER HRRR
MODEL LATE MORNING INTO EARLY AFTN. ELSEWHERE WILL CERTAINLY BE MORE
CLOUDS THAN LAST COUPLE DAYS AS CIRRUS AND MORE PRONOUNCED AREA OF
AC/AS OVER MN SLIDES IN FOR THE AFTN. EVEN SO THOUGH...WARM START
SHOULD STILL ALLOW MAX TEMPS TO REACH WELL INTO THE 60S. RH VALUES A
BIT HIGHER THAN BONE DRY CONDITIONS SEEN TUE/WED WHERE RH BOTTOMED
OUT AROUND 10 PCT OVER INTERIOR WEST. FOR TODAY IN THOSE AREAS...
EXPECT MAINLY 18-25 PCT RANGE AT THE LOW-END. WINDS LESS THAN 10 MPH
MOST AREAS WITH LOCAL LAKE BREEZES CNTRL. OVERALL APPEARS TO NOT BE
AS MUCH OF ISSUE WITH FIRE WEATHER TODAY COMPARED TO TUE OR WED.
NORTHERN STREAM SHORTWAVE CROSSES NORTHERN ONTARIO TONIGHT WITH
TAIL OF ENHANCED CLOUD GRAZING CWA...ALONG WITH THE PASSAGE OF SFC
TROUGH...MORE OF A WIND SHIFT FM SW TO NW LATE TONIGHT. SINCE 1000-
700MB LAPSE RATES ARE HIGH...OVER 7C/KM BY LATE AFTN...AND FORCING
IS MOVING THROUGH WITH SUFFICIENT MOISTURE ALOFT...THINK THERE IS A
CHANCE OF SPRINKLES/VIRGA THIS EVENING AS THE FORCING MOVES
THROUGH...PERHAPS SIMILAR TO WHAT OCCURRED MON AFTN/EVENING. THAT
SAID...WINDS IN MIXED LAYER THIS EVENING DO INCREASE BY 03Z WITH 25-
30 KTS AT TOP PARTS OF THE MIXED LAYER. SO...FEASIBLE THAT GUSTY
WINDS COULD OCCUR IN THE VCNTY OF ANY WELL DEVELOPED CU OR
VIRGA/SPRINKLES. ALL FORCING IS OUT OF HERE BY MIDNIGHT AND SCT-BKN
CLOUDS SHOULD EXIT OVERNIGHT. SKIES WILL BE MAINLY CLEAR BY DAYBREAK
ON FRIDAY. LOWS TONIGHT SHOULD REMAIN ABOVE FREEZING ALL AREAS GIVEN
THE WINDS AND CLOUDS MOST OF THE NIGHT AND LACK OF COLD AIR BEHIND
THE TROUGH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT WED APR 15 2015
AFTER A QUIET AND GENERALLY WARM REST OF THIS WEEK...SIGNIFICANT
AMPLIFICATION OF THE FLOW IS EXPECTED THIS WEEKEND AND EARLY NEXT
WEEK AS A SHARP RIDGE BUILDS THRU WRN CANADA. THIS WILL FORCE A DEEP
TROF TO DEVELOP DOWNSTREAM WITH AXIS ROUGHLY OVER THE MISSISSIPPI
VALLEY BY MON. TYPICAL FOR THIS TIME OF YEAR...CLOSED LOWS
FREQUENTLY DEVELOP...AND THIS TROF WILL QUICKLY EVOLVE IN THAT
DIRECTION AS MAJORITY OF GUIDANCE INCLUDING GFS/GEM ENSEMBLES SHOW
EVOLUTION INTO A LARGE/COLD MID-LEVEL LOW OVER THE VICINITY OF THE
UPPER GREAT LAKES. MAY BE DIFFICULT TO DISLODGE THE LOW NEXT WEEK
ONCE IT DEVELOPS. SO...AFTER A WARM/DRY REST OF THIS WEEK...NEXT
WEEK WILL BE COLD AND GENERALLY UNSETTLED WITH PERIODIC CHANCES OF
SNOW AND RAIN SHOWERS. FROM A PCPN PERSPECTIVE...THE BIGGEST
CHALLENGE IS HOW THE SHARP PATTERN AMPLIFICATION INTERACTS WITH WHAT
IS CURRENTLY AN IMPRESSIVE LOOKING TROF CLOSING OFF OVER UT/CO.
MEDIUM RANGE GUIDANCE TODAY IS IN MUCH BETTER AGREEMENT IN SHOWING
THE AMPLIFICATION OF THE FLOW PICKING UP THE MID-LEVEL LOW AND
FORCING THE OPENED UP SYSTEM/REMNANT ENERGY NE INTO THE GREAT LAKES
REGION. RANGE OF POSSIBILITIES STILL INCLUDE A SIGNIFICANT RAIN
EVENT TO A RAIN CHANGING TO ACCUMULATING SNOW EVENT TO MINIMAL PCPN
IF THE SRN ENERGY DOES NOT LIFT FAR ENOUGH N AND W WITHIN THE
AMPLIFYING PATTERN. OPERATIONAL MEDIUM RANGE MODELS WEAKEN THE
ENERGY DRAMATICALLY AS IT LIFTS NE (WILL BE INTERESTING TO SEE IF
THAT ACTUALLY HAPPENS)...SO THE LOWEST PROBABILITY OUTCOME RIGHT NOW
IS ONE THAT BRINGS A SIGNIFICANT PCPN PRODUCING SYSTEM WITH A
PROMINENT DEFORMATION PCPN SHIELD INTO THE UPPER LAKES EARLY NEXT
WEEK. THAT SAID...THERE HAVE BEEN AND THERE STILL ARE SOME GFS/GEM
ENSEMBLES THAT DO SHOW SUCH A SCENARIO...SO IT CAN`T BE RULED OUT.
BEGINNING THU NIGHT...TAIL END OF SHORTWAVE TRACKING FROM HUDSON BAY
INTO QUEBEC WILL PASS ACROSS THE AREA THU NIGHT. FORCING FROM THE
RIGHT ENTRANCE OF AN UPPER JET STREAK AND MAIN DEEP LAYER QVECTOR
CONVERGENCE...WEAK AT THAT...PASS N OF THE AREA...SUPPORTING BEST
CHC OF -SHRA N OF HERE. ACROSS UPPER MI...VERY WEAK FORCING/WEAK
FRONTAL BOUNDARY AND WEAK MOISTURE TRANSPORT ALL SUGGEST PROSPECT OF
ANY PCPN IS VERY LIMITED AS SHORTWAVE PASSES. THUS...WILL RETAIN DRY
FCST FOR THU NIGHT.
IN THE MAIN FLOW TO THE N...ANOTHER SHORTWAVE IS FCST TO TRACK FROM
THE CANADIAN ROCKIES THU AFTN TO NRN ONTARIO FRI. MODELS HAVE
TRENDED TO MUCH BETTER AGREEMENT ON THIS WAVE WITH GEM/GFS/NAM
MOVING TO THE ECMWF SCENARIO WHICH HAS BEEN FARTHER N THAN THOSE
MODELS FOR SEVERAL RUNS. WITH THE TRACK OF THE SHORTWAVE JUST N OF
LAKE SUPERIOR...BEST FORCING AND POTENTIAL FOR PCPN WILL PASS BY TO
THE N. REMOVED SCHC POPS FROM INHERITED FCST IN FAVOR OF DRY
WEATHER. EXPECT HIGH TEMPS FRI IN THE 60S AWAY FROM LAKE MODERATION.
A FEW SPOTS MAY REACH 70F. INTERIOR RH SHOULD FALL TO 25-30PCT...
AND WINDS MAY BE A LITTLE GUSTY TO 15-20MPH AT TIMES...KEEPING FIRE
WX A CONCERN.
IN THE WAKE OF THE SHORTWAVE...HIGH PRES BUILDS INTO THE AREA FOR
SAT. WITH THE HIGH ENDING UP OVER LAKE SUPERIOR IN THE AFTN...IT
WILL BE A MUCH COOLER DAY NEAR LAKE SUPERIOR...ESPECIALLY FROM THE
KEWEENAW EASTWARD. RIGHT ALONG THE SHORE...TEMPS SHOULDN`T GET OUT
OF THE 30S. IN THE INTERIOR W HALF...TEMPS SHOULD RISE TO AROUND 60F
UNDER SUNNY SKIES.
SUN/MON...WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH OF CURRENT
AND RECENT MEDIUM RANGE GUIDANCE FOR THE EVOLUTION OF THE SRN
ROCKIES ENERGY INTO THE GREAT LAKES AHEAD OF THE TROF AMPLIFICATION
OCCURRING INTO THE PLAINS/MISSISSIPPI VALLEY. IT APPEARS THERE MAY
END UP BEING TWO SURGES OF PCPN OR SFC LOW PRES WAVES...ONE
ASSOCIATED WITH LEAD ENERGY SWINGING UP FROM MEXICO AND A SECOND
ASSOCIATED WITH THE MAIN REMNANT OF THE ROCKIES MID LEVEL LOW.
LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN SPREADING INTO UPPER MI SUN
AND THEN CONTINUE INTO MON. AIR MASS SHOULD COOL ENOUGH TO ALLOW
SOME SNOW TO BEGIN MIXING WITH THE RAIN OVER THE W ON MON. PTYPE
WILL THEN BECOME ALL SNOW ACROSS THE FCST AREA MON NIGHT FOR
WHATEVER PCPN LINGERS.
TUE/WED...LARGE/COLD MID-LEVEL LOW WILL HAVE DEVELOPED AND WILL BE
CENTERED IN THE VCNTY OF THE UPPER GREAT LAKES. COLD AIR
ALOFT/SPRING DAYTIME HEATING AND POTENTIAL OF SHORTWAVES ROTATING
THRU THE AREA WITHIN THE LARGE MID-LEVEL LOW CIRCULATION SUGGEST AT
LEAST SCT SHOWERY PCPN (MOSTLY SNOW BUT SOME RAIN AS WELL DURING
PEAK HEATING) BOTH DAYS WITH BEST COVERAGE IN THE AFTN INLAND FROM
LAKE SUPERIOR WHERE HEATING IS BEST. HIGH TEMPS BOTH DAYS SHOULD BE
IN THE MID 30S TO MID 40S...WARMEST SCNTRL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 742 AM EDT THU APR 16 2015
EVEN THOUGH MID TO HIGH CLOUDS WILL THICKEN THROUGH THIS EVENING AS
A WEAK UPR DISTURBANCE MOVES TOWARD THE UPR LKS AND MOISTURE
INCREASES ALOFT...LINGERING LLVL DRY AIR ASSOCIATED WITH A SFC HI
PRES RDG WL BRING CONTINUED VFR CONDITIONS. EXPECT A SFC TROUGH TO
CROSS UPR MICHIGAN TONIGHT WITH A WIND SHIFT FM SW TO NW. WINDS
SHOULD STAY LIGHT THOUGH. IT IS POSSIBLE THERE COULD BE A LGT SHOWER
OR SPRINKLE AROUND EARLY THIS EVENING AHEAD OF THE FRONT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 435 AM EDT THU APR 16 2015
NO WIDESPREAD GALES ARE EXPECTED THROUGH THE FORECAST PERIOD...BUT
THERE WILL BE A FEW PERIODS OF STRONGER WINDS STARTING THIS WEEKEND.
WINDS EXPECTED TO REMAIN AT OR BLO 20 KTS THROUGH FRIDAY NIGHT AS
PRESSURE GRADIENT IS WEAK. HIGH PRESSURE MOVING ACROSS ON SATURDAY
WITH LOW PRESSURE FOLLOWING OVER SCNTRL CANADA ON SUNDAY WILL RESULT
IN SETUP FOR STRONGER EAST-NORTHEAST WINDS TO 30 KTS OVER WESTERN LK
SUPERIOR SATURDAY AND SATURDAY NIGHT. STRONGEST WINDS WILL BE TOWARD
HEAD OF LK SUPERIOR NEAR DULUTH AND SUPERIOR. BY SUNDAY...AS THE LOW
PRESSURE SYSTEM APPROACHES...SOUTHEAST WINDS TO 30 KTS WILL BE
POSSIBLE OVER EASTERN HALF OF LK SUPERIOR WHILE WINDS DIMINISH IN
THE WEST. THE LOW CROSSES THE UPPER GREAT LAKES BY MONDAY WHILE
MERGING WITH ANOTHER LOW LIFTING IN FM THE CENTRAL PLAINS. EXPECT
WEST WINDS UP TO 30 KTS OVER MUCH OF THE LAKE LATER MONDAY INTO
TUESDAY IN WAKE OF THIS COMBINED LOW AS IT MOVES TO THE LOWER GREAT
LAKES.
&&
.HYDROLOGY...
ISSUED AT 332 PM EDT WED APR 15 2015
SEEMS THAT WITHOUT ANY SIGNIFICANT ADDITIONAL PRECIPITATION ADDED TO
THE ONGOING SNOWMELT...AT LEAST FOR THE REST OF THIS WEEK...MAINLY
LOOKING AT A FEW BANKFULL ISSUES ON SOME RIVERS WITH CONTINUATION OF
LOW-END ADVISORIES. BELOW NORMAL TEMPERATURES ARE EXPECTED MONDAY
THROUGH MUCH OF NEXT WEEK...WHICH WILL LIMIT MELTING OF ANY
REMAINING SNOW PACK AND REDUCE RIVER LEVELS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLA
MARINE...JLA
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
658 AM EDT THU APR 16 2015
.UPDATE...
ISSUED AT 657 AM EDT THU APR 16 2015
DECIDED TO PUT SPRINKLES INTO FORECAST OVER EASTERN CWA /ISQ-ERY/
MID MORNING INTO EARLY AFTN AS BAND OF SHOWERS OVER LOWER MICHIGAN
CONTINUES TO LIFT NORTHWARD. EVEN THOUGH SHRA WILL BE RUNNING INTO
THE DRY AIRMASS OVER AREA AS SEEN ON 00Z APX AND DTX RAOBS...THINK
ENOUGH FOCUS FM SHORTWAVE AND MOISTURE TRANSPORT AT H85-H7 IS GOING
TO END UP STRONG/PERSISTENT ENOUGH TO OUTWEIGH THE LOW-LEVEL DRY
AIR. VARIOUS HIGH RES MODELS AND THE 06Z/07Z HRRR REFLECTIVITY
OUTPUT POINT TO AT LEAST A BRIEF PERIOD OF LGT RAIN/SPRINKLES.
BEEFED UP SKY COVER SOME MORE AS WELL. OTHER THAN TWEAKS FOR VERY
SHORT TERM TEMP/DWPNT TRENDS...NO OTHER CHANGES WERE NEEDED TO
FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 435 AM EDT THU APR 16 2015
SHORTWAVE RIDGING PERSISTS TODAY BTWN NORTHERN STREAM SHORTWAVE THAT
CROSSES MANITOBA/NORTHERN ONTARIO AND CUTOFF LOW OVER FOUR CORNERS
OF SW CONUS. WEAK AREAS OF VORTICITY LIFTING INTO THE RIDGE BRINGING
A PUSH OF MID-LEVEL MOISTURE ADVECTION AROUND H7. DECENT AREA OF
SHRA IS LIFTING NORTHWARD OVER WESTERN LOWER MICHIGAN ON NORTH EDGE
OF MOISTURE TRANSPORT AT H85-H7 AND THIS COULD BRING VIRGA OR A FEW
SPRINKLES TO EASTERN CWA...POSSIBLY AS FAR WEST AS KESC PER HRRR
MODEL LATE MORNING INTO EARLY AFTN. ELSEWHERE WILL CERTAINLY BE MORE
CLOUDS THAN LAST COUPLE DAYS AS CIRRUS AND MORE PRONOUNCED AREA OF
AC/AS OVER MN SLIDES IN FOR THE AFTN. EVEN SO THOUGH...WARM START
SHOULD STILL ALLOW MAX TEMPS TO REACH WELL INTO THE 60S. RH VALUES A
BIT HIGHER THAN BONE DRY CONDITIONS SEEN TUE/WED WHERE RH BOTTOMED
OUT AROUND 10 PCT OVER INTERIOR WEST. FOR TODAY IN THOSE AREAS...
EXPECT MAINLY 18-25 PCT RANGE AT THE LOW-END. WINDS LESS THAN 10 MPH
MOST AREAS WITH LOCAL LAKE BREEZES CNTRL. OVERALL APPEARS TO NOT BE
AS MUCH OF ISSUE WITH FIRE WEATHER TODAY COMPARED TO TUE OR WED.
NORTHERN STREAM SHORTWAVE CROSSES NORTHERN ONTARIO TONIGHT WITH
TAIL OF ENHANCED CLOUD GRAZING CWA...ALONG WITH THE PASSAGE OF SFC
TROUGH...MORE OF A WIND SHIFT FM SW TO NW LATE TONIGHT. SINCE 1000-
700MB LAPSE RATES ARE HIGH...OVER 7C/KM BY LATE AFTN...AND FORCING
IS MOVING THROUGH WITH SUFFICIENT MOISTURE ALOFT...THINK THERE IS A
CHANCE OF SPRINKLES/VIRGA THIS EVENING AS THE FORCING MOVES
THROUGH...PERHAPS SIMILAR TO WHAT OCCURRED MON AFTN/EVENING. THAT
SAID...WINDS IN MIXED LAYER THIS EVENING DO INCREASE BY 03Z WITH 25-
30 KTS AT TOP PARTS OF THE MIXED LAYER. SO...FEASIBLE THAT GUSTY
WINDS COULD OCCUR IN THE VCNTY OF ANY WELL DEVELOPED CU OR
VIRGA/SPRINKLES. ALL FORCING IS OUT OF HERE BY MIDNIGHT AND SCT-BKN
CLOUDS SHOULD EXIT OVERNIGHT. SKIES WILL BE MAINLY CLEAR BY DAYBREAK
ON FRIDAY. LOWS TONIGHT SHOULD REMAIN ABOVE FREEZING ALL AREAS GIVEN
THE WINDS AND CLOUDS MOST OF THE NIGHT AND LACK OF COLD AIR BEHIND
THE TROUGH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT WED APR 15 2015
AFTER A QUIET AND GENERALLY WARM REST OF THIS WEEK...SIGNIFICANT
AMPLIFICATION OF THE FLOW IS EXPECTED THIS WEEKEND AND EARLY NEXT
WEEK AS A SHARP RIDGE BUILDS THRU WRN CANADA. THIS WILL FORCE A DEEP
TROF TO DEVELOP DOWNSTREAM WITH AXIS ROUGHLY OVER THE MISSISSIPPI
VALLEY BY MON. TYPICAL FOR THIS TIME OF YEAR...CLOSED LOWS
FREQUENTLY DEVELOP...AND THIS TROF WILL QUICKLY EVOLVE IN THAT
DIRECTION AS MAJORITY OF GUIDANCE INCLUDING GFS/GEM ENSEMBLES SHOW
EVOLUTION INTO A LARGE/COLD MID-LEVEL LOW OVER THE VICINITY OF THE
UPPER GREAT LAKES. MAY BE DIFFICULT TO DISLODGE THE LOW NEXT WEEK
ONCE IT DEVELOPS. SO...AFTER A WARM/DRY REST OF THIS WEEK...NEXT
WEEK WILL BE COLD AND GENERALLY UNSETTLED WITH PERIODIC CHANCES OF
SNOW AND RAIN SHOWERS. FROM A PCPN PERSPECTIVE...THE BIGGEST
CHALLENGE IS HOW THE SHARP PATTERN AMPLIFICATION INTERACTS WITH WHAT
IS CURRENTLY AN IMPRESSIVE LOOKING TROF CLOSING OFF OVER UT/CO.
MEDIUM RANGE GUIDANCE TODAY IS IN MUCH BETTER AGREEMENT IN SHOWING
THE AMPLIFICATION OF THE FLOW PICKING UP THE MID-LEVEL LOW AND
FORCING THE OPENED UP SYSTEM/REMNANT ENERGY NE INTO THE GREAT LAKES
REGION. RANGE OF POSSIBILITIES STILL INCLUDE A SIGNIFICANT RAIN
EVENT TO A RAIN CHANGING TO ACCUMULATING SNOW EVENT TO MINIMAL PCPN
IF THE SRN ENERGY DOES NOT LIFT FAR ENOUGH N AND W WITHIN THE
AMPLIFYING PATTERN. OPERATIONAL MEDIUM RANGE MODELS WEAKEN THE
ENERGY DRAMATICALLY AS IT LIFTS NE (WILL BE INTERESTING TO SEE IF
THAT ACTUALLY HAPPENS)...SO THE LOWEST PROBABILITY OUTCOME RIGHT NOW
IS ONE THAT BRINGS A SIGNIFICANT PCPN PRODUCING SYSTEM WITH A
PROMINENT DEFORMATION PCPN SHIELD INTO THE UPPER LAKES EARLY NEXT
WEEK. THAT SAID...THERE HAVE BEEN AND THERE STILL ARE SOME GFS/GEM
ENSEMBLES THAT DO SHOW SUCH A SCENARIO...SO IT CAN`T BE RULED OUT.
BEGINNING THU NIGHT...TAIL END OF SHORTWAVE TRACKING FROM HUDSON BAY
INTO QUEBEC WILL PASS ACROSS THE AREA THU NIGHT. FORCING FROM THE
RIGHT ENTRANCE OF AN UPPER JET STREAK AND MAIN DEEP LAYER QVECTOR
CONVERGENCE...WEAK AT THAT...PASS N OF THE AREA...SUPPORTING BEST
CHC OF -SHRA N OF HERE. ACROSS UPPER MI...VERY WEAK FORCING/WEAK
FRONTAL BOUNDARY AND WEAK MOISTURE TRANSPORT ALL SUGGEST PROSPECT OF
ANY PCPN IS VERY LIMITED AS SHORTWAVE PASSES. THUS...WILL RETAIN DRY
FCST FOR THU NIGHT.
IN THE MAIN FLOW TO THE N...ANOTHER SHORTWAVE IS FCST TO TRACK FROM
THE CANADIAN ROCKIES THU AFTN TO NRN ONTARIO FRI. MODELS HAVE
TRENDED TO MUCH BETTER AGREEMENT ON THIS WAVE WITH GEM/GFS/NAM
MOVING TO THE ECMWF SCENARIO WHICH HAS BEEN FARTHER N THAN THOSE
MODELS FOR SEVERAL RUNS. WITH THE TRACK OF THE SHORTWAVE JUST N OF
LAKE SUPERIOR...BEST FORCING AND POTENTIAL FOR PCPN WILL PASS BY TO
THE N. REMOVED SCHC POPS FROM INHERITED FCST IN FAVOR OF DRY
WEATHER. EXPECT HIGH TEMPS FRI IN THE 60S AWAY FROM LAKE MODERATION.
A FEW SPOTS MAY REACH 70F. INTERIOR RH SHOULD FALL TO 25-30PCT...
AND WINDS MAY BE A LITTLE GUSTY TO 15-20MPH AT TIMES...KEEPING FIRE
WX A CONCERN.
IN THE WAKE OF THE SHORTWAVE...HIGH PRES BUILDS INTO THE AREA FOR
SAT. WITH THE HIGH ENDING UP OVER LAKE SUPERIOR IN THE AFTN...IT
WILL BE A MUCH COOLER DAY NEAR LAKE SUPERIOR...ESPECIALLY FROM THE
KEWEENAW EASTWARD. RIGHT ALONG THE SHORE...TEMPS SHOULDN`T GET OUT
OF THE 30S. IN THE INTERIOR W HALF...TEMPS SHOULD RISE TO AROUND 60F
UNDER SUNNY SKIES.
SUN/MON...WILL CONTINUE TO UTILIZE A CONSENSUS APPROACH OF CURRENT
AND RECENT MEDIUM RANGE GUIDANCE FOR THE EVOLUTION OF THE SRN
ROCKIES ENERGY INTO THE GREAT LAKES AHEAD OF THE TROF AMPLIFICATION
OCCURRING INTO THE PLAINS/MISSISSIPPI VALLEY. IT APPEARS THERE MAY
END UP BEING TWO SURGES OF PCPN OR SFC LOW PRES WAVES...ONE
ASSOCIATED WITH LEAD ENERGY SWINGING UP FROM MEXICO AND A SECOND
ASSOCIATED WITH THE MAIN REMNANT OF THE ROCKIES MID LEVEL LOW.
LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN SPREADING INTO UPPER MI SUN
AND THEN CONTINUE INTO MON. AIR MASS SHOULD COOL ENOUGH TO ALLOW
SOME SNOW TO BEGIN MIXING WITH THE RAIN OVER THE W ON MON. PTYPE
WILL THEN BECOME ALL SNOW ACROSS THE FCST AREA MON NIGHT FOR
WHATEVER PCPN LINGERS.
TUE/WED...LARGE/COLD MID-LEVEL LOW WILL HAVE DEVELOPED AND WILL BE
CENTERED IN THE VCNTY OF THE UPPER GREAT LAKES. COLD AIR
ALOFT/SPRING DAYTIME HEATING AND POTENTIAL OF SHORTWAVES ROTATING
THRU THE AREA WITHIN THE LARGE MID-LEVEL LOW CIRCULATION SUGGEST AT
LEAST SCT SHOWERY PCPN (MOSTLY SNOW BUT SOME RAIN AS WELL DURING
PEAK HEATING) BOTH DAYS WITH BEST COVERAGE IN THE AFTN INLAND FROM
LAKE SUPERIOR WHERE HEATING IS BEST. HIGH TEMPS BOTH DAYS SHOULD BE
IN THE MID 30S TO MID 40S...WARMEST SCNTRL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 208 AM EDT THU APR 16 2015
ALTHOUGH THERE WL BE SOME THICKENING HI/MID CLDS LATER TODAY AS A WEAK
UPR DISTURBANCE MOVES TOWARD THE UPR LKS...LINGERING LLVL DRY AIR
ASSOCIATED WITH A SFC HI PRES RDG WL BRING CONTINUED VFR CONDITIONS.
STRONGER S WINDS ABOVE LIGHTER GROUND LVL WINDS WITHIN A NEAR SFC
STABLE LYR CAUSED BY NOCTURNAL COOLING WL ALLOW FOR SOME LLWS AT THE
SITES EARLY THIS MRNG...BUT WINDS WL DIMINISH SGNFTLY BY SUNRISE...
ENDING THE LLWS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 435 AM EDT THU APR 16 2015
NO WIDESPREAD GALES ARE EXPECTED THROUGH THE FORECAST PERIOD...BUT
THERE WILL BE A FEW PERIODS OF STRONGER WINDS STARTING THIS WEEKEND.
WINDS EXPECTED TO REMAIN AT OR BLO 20 KTS THROUGH FRIDAY NIGHT AS
PRESSURE GRADIENT IS WEAK. HIGH PRESSURE MOVING ACROSS ON SATURDAY
WITH LOW PRESSURE FOLLOWING OVER SCNTRL CANADA ON SUNDAY WILL RESULT
IN SETUP FOR STRONGER EAST-NORTHEAST WINDS TO 30 KTS OVER WESTERN LK
SUPERIOR SATURDAY AND SATURDAY NIGHT. STRONGEST WINDS WILL BE TOWARD
HEAD OF LK SUPERIOR NEAR DULUTH AND SUPERIOR. BY SUNDAY...AS THE LOW
PRESSURE SYSTEM APPROACHES...SOUTHEAST WINDS TO 30 KTS WILL BE
POSSIBLE OVER EASTERN HALF OF LK SUPERIOR WHILE WINDS DIMINISH IN
THE WEST. THE LOW CROSSES THE UPPER GREAT LAKES BY MONDAY WHILE
MERGING WITH ANOTHER LOW LIFTING IN FM THE CENTRAL PLAINS. EXPECT
WEST WINDS UP TO 30 KTS OVER MUCH OF THE LAKE LATER MONDAY INTO
TUESDAY IN WAKE OF THIS COMBINED LOW AS IT MOVES TO THE LOWER GREAT
LAKES.
&&
.HYDROLOGY...
ISSUED AT 332 PM EDT WED APR 15 2015
SEEMS THAT WITHOUT ANY SIGNIFICANT ADDITIONAL PRECIPITATION ADDED TO
THE ONGOING SNOWMELT...AT LEAST FOR THE REST OF THIS WEEK...MAINLY
LOOKING AT A FEW BANKFULL ISSUES ON SOME RIVERS WITH CONTINUATION OF
LOW-END ADVISORIES. BELOW NORMAL TEMPERATURES ARE EXPECTED MONDAY
THROUGH MUCH OF NEXT WEEK...WHICH WILL LIMIT MELTING OF ANY
REMAINING SNOW PACK AND REDUCE RIVER LEVELS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...KC
MARINE...JLA
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
345 AM CDT THU APR 16 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 343 AM CDT THU APR 16 2015
CURRENT RADAR IMAGERY SHOWS SCATTERED ECHOS LIFTING NORTH OVER MUCH
OF MN EARLY THIS MORNING IN A REGION OF MID LEVEL WARM AIR ADVECTION
AHEAD OF AN APPROACHING COLD FRONT. HOWEVER...THE VERY DRY AIR IN
PLACE IS LIMITING MORE THAN A FEW SPRINKLES FROM REACHING THE GROUND
WITH CEILINGS REMAINING ABOVE 6 KFT. THE MORNING CONVECTION WILL
DISSIPATE AFTER SUNRISE...REDEVELOPING ALONG THE FRONTAL BOUNDARY
THIS AFTERNOON IN THE BORDERLAND/ARROWHEAD REGION. ANY SHOWERS THAT
DEVELOP LATE TODAY WILL AGAIN HAVE TO CONTENT WITH VERY DRY LOW
LEVELS...RESULTING IN PRIMARILY VIRGA AND LIMITING ANY QPF TO ONLY A
FEW HUNDREDTHS AT BEST. LOCATIONS THAT DO RECEIVE A PASSING
SPRINKLE/VIRGA CAN EXPECT A LOCALIZED WIND GUST TO 25 MPH THIS
AFTERNOON...MAINLY IN THE MN ARROWHEAD. THE FRONT WILL REACH THE
WISCONSIN ZONES THIS EVENING...BRINGING INCREASING CLOUDS AND
LIGHT AND VARIABLE WINDS. THE CLOUD COVER TODAY WILL ALLOW FOR
SOMEWHAT COOLER TEMPERATURES THAN THE PAST FEW DAYS...TOPPING OUT
IN THE LOW TO MIDDLE 60S TODAY. HOWEVER...THIS IS STILL 10 TO 15
DEGREES ABOVE NORMAL FOR MID APRIL.
TEMPERATURES CLOSER TO 70 WILL RETURN WITH SUNNY SKIES FRIDAY AS
RIDGE OF HIGH PRESSURE BUILDS ACROSS THE NORTHLAND. A CORRIDOR
OF VERY DRY AIR WITH RH VALUES IN TEENS TO LOW 20S IS EXPECTED TO
SETTLE OVER THE NE MINN AND FAR NRN WISCONSIN THROUGH FRIDAY
EVENING. WINDS WILL BE OUT OF THE WEST AROUND 5 TO 10 MPH OVER MOST
AREAS FRIDAY...EXCEPT STRONGER WITH GUSTS TO 25 MPH ALONG THE
INTERNATIONAL BORDER AS A COLD FRONT IN ONTARIO APPROACHES THE
BORDERLAND.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM CDT THU APR 16 2015
FRIDAY NIGHT...A SUBTLE COLD FRONT WILL MOVE INTO THE NORTHLAND IN
THE WAKE OF A WEAK LOW MOVING THROUGH ONTARIO INTO QUEBEC. HIGH
PRESSURE WILL BUILD INTO ONTARIO AND THE LAKE SUPERIOR REGION IN
THE WAKE OF THE FRONT. THE NORTHLAND CAN EXPECT A CLEAR AND COOL
NIGHT WITH LIGHT WINDS.
SATURDAY...THE DAY WILL BEGIN COOL AND CLEAR. EASTERLY WINDS WILL
DEVELOP AS THE HIGH PRESSURE SHIFTS EAST TOWARDS QUEBEC AND THE
EASTERN GREAT LAKES AND IN RESPONSE TO LOW PRESSURE BUILDING INTO
THE AMERICAN AND CANADIAN PLAINS. THERE WILL BE A CUTOFF LOW OVER
THE HIGH PLAINS OF COLORADO...AND A DEEPENING LOW IN CENTRAL
SASKATCHEWAN MOVING TO THE SE. THERE WILL BE INCREASING CLOUD COVER
OVER THE NORTHLAND SATURDAY AS THE MOISTURE FROM THE CUTOFF LOW
BEGINS TO MOVE INTO THE NORTHLAND FROM THE SOUTH. THE EAST TO NE
FLOW OFF OF LAKE SUPERIOR WILL KEEP AREAS NEAR LAKE SUPERIOR COOL IN
THE UPPER 40S AND 50S...BUT AREAS OF THE NORTHLAND WELL INLAND
SHOULD CLIMB TO THE LOWER 60S.
SATURDAY NIGHT AND SUNDAY...THE LOW IN SASKATCHEWAN WILL DEEPEN AS
IT MOVES SE INTO MANITOBA. THE CUTOFF LOW NEAR THE COLORADO/NEBRASKA
BORDER WILL MOVE ENE TOWARDS THE UPPER MIDWEST. SURFACE LOW PRESSURE
WILL DEVELOP IN THE DAKOTAS SATURDAY NIGHT AND MOVE INTO THE
NORTHLAND AND MERGE WITH THE LOW IN SOUTH CENTRAL CANADA. THE LOW
PRESSURE WILL BRING A SURGE OF HUMID AIR AND RAIN INTO THE NORTHLAND
SATURDAY NIGHT AND SUNDAY. THE MODELS ARE IN BETTER AGREEMENT ON THE
TIMING OF THIS PCPN COMPARED TO PREVIOUS RUNS...ESPECIALLY BETWEEN
THE GFS AND ECMWF. THEREFORE...WAS ABLE TO INCREASE PCPN CHANCES BY
ABOUT 10 TO 20 PERCENT. THE PRECIPITABLE WATER VALUES WILL INCREASE
TO AROUND 1 INCH. THE NORTHLAND WILL LIKELY GET AT LEAST WIDESPREAD
RAINFALL OF 0.50" TO 0.75" OF RAINFALL WITH THE PASSAGE OF THIS LOW
PRESSURE.
EARLY NEXT WEEK...THE LOW PRESSURE SYSTEMS WILL MERGE AND DEEPEN
INTO A LARGE LOW PRESSURE SYSTEM OVER THE GREAT LAKES AND ONTARIO
REGION. THE NORTHLAND CAN EXPECT A PERIOD OF COOLER AND CLOUDIER
WEATHER FOR THE MONDAY THROUGH WEDNESDAY TIMEFRAME WITH CHANCES OF
RAIN AND LIGHT SNOW SHOWERS. TEMPERATURES WILL BE ABOUT 10 DEGREES
BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 104 AM CDT THU APR 16 2015
VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST. INCREASING AMOUNT
OF MOISTURE MOVING INTO THE NORTHLAND AS HIGH PRESSURE DEPARTS TO
THE EAST...AND AN UPPER LEVEL DISTURBANCE MOVES THROUGH MINNESOTA.
LAST SEVERAL HRRR RUNS SHOW THE BEST CHANCE OF -RA AT KBRD. OTHER
MN TERMINALS MAY SEE VCSH BETWEEN 14Z AND 20Z THIS MORNING...BUT
NOT VERY CONFIDENT THAT MUCH IF ANY WILL REACH THE GROUND AS
LATEST GFS AND NAM SOUNDINGS KEEP THE LOW LEVELS FAIRLY DRY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 62 37 67 39 / 10 10 0 0
INL 62 31 67 33 / 20 10 10 0
BRD 67 36 70 41 / 20 10 0 0
HYR 65 37 70 38 / 10 10 0 0
ASX 67 37 69 37 / 10 10 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GRANING
LONG TERM...GROCHOCINSKI
AVIATION...GROCHOCINSKI/WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
105 AM CDT THU APR 16 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY AFTERNOON)
ISSUED AT 326 PM CDT WED APR 15 2015
MAIN CONCERNS IN THE SHORT TERM REMAIN FOCUSED AROUND THE GUSTY
SOUTH WINDS AND VERY DRY CONDITIONS ACROSS THE REGION THIS
EVENING...THE POTENTIAL FOR LIGHT RAIN SHOWERS OVERNIGHT TONIGHT
AND THROUGH THE DAY THURSDAY ACROSS NE MN.
HIGH PRESSURE AT THE SURFACE REMAINS SITUATED OVER THE NRN GREAT
LAKES WITH AN ELONGATED SFC TROUGH EXTENDING FROM NRN MANITOBA SWD
INTO THE WRN DAKOTAS. THE COMBINATION OF THESE TWO FEATURES IS
PRODUCING A TIGHT SFC PRESSURE GRADIENT OVER THE ERN DAKOTAS AND
MOST OF MINNESOTA. GUSTY SOUTH WINDS HAVE DEVELOPED OVER THE
REGION WITH SUSTAINED WINDS AROUND 10 TO 20 MPH AND GUSTS UP TO 35
MPH HAVE BEEN OBSERVED THIS AFTERNOON.
AN EMBEDDED S/W IS CURRENTLY LIFTING TO THE NORTH THROUGH THE MID
MS VALLEY REGION THIS AFTERNOON AND TRYING TO UNDERCUT THE SFC
HIGH WITH CLOUD COVER AND LIGHT RAIN. HOWEVER...FOR THE TIME THE
DRY AIR MASS IS WINNING OUT AND KEEPING MUCH OF THE AREA FREE OF
PRECIPITATION.
THE INFLUENCE FROM THE RIDGE TO THE EAST WILL EVENTUALLY MOVE TO
THE EAST TONIGHT AS THE UPPER TROUGH LIFTS INTO MN. THIS WILL
ALLOW FOR A STRONGER PUSH OF CLOUD COVER FROM THE SOUTH ALONG WITH
LOW CHANCES FOR LIGHT RAIN SHOWERS...MAINLY OVER N-CENTRAL MN JUST
AFTER MIDNIGHT AND THEN EVENTUALLY SHIFTING TO THE EAST INTO THE
ARROWHEAD THROUGH THE DAY THURSDAY AS THE SFC TROUGH/COLD FRONT IS
DRAGGED SLOWLY TO THE EAST. ONLY EXPECTING LIGHT AMOUNTS LESS
THAN A TENTH OF AN INCH WITH THIS RAIN EVENT. HIGH PRESSURE WILL
BUILD IN BRIEFLY BEHIND THE DEPARTING COLD FRONT LATE THUR
AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 326 PM CDT WED APR 15 2015
SFC RIDGING COVERS THE FORECAST AREA THURSDAY NIGHT THROUGH
SATURDAY. THE GFS IS WAY OVERDONE WITH ITS HANDLING OF A SYSTEM ON
SATURDAY AND WAS IGNORED. SATURDAY NIGHT FINDS RAIN ARRIVING OVER
MUCH OF THE AREA AS A CLOSED UPPER LOW DEVELOPS OVER THE MANITOBA
LAKES. AS THIS UPPER LOW DEEPENS WHILE MOVING SLOWLY EASTWARD...IT
MERGES WITH A SOUTHERN STREAM SYSTEM ON SUNDAY. THIS PULLS MORE
MOISTURE INTO THE AREA FOR THIS PHASING SYSTEM TO FEED OFF OF. ON
SUNDAY NIGHT...THE UPPER LOW CONTINUES TO DEEPEN AND BEGINS TO PULL
DOWN COLDER AIR FROM THE ARCTIC...MUCH LIKE A WINTER SYSTEM.
HOWEVER...AT THIS TIME OF THE YEAR IT IS BECOMING MORE DIFFICULT TO
HAVE A TRUE SNOW EVENT. THIS SYSTEM THEN BECOMES LOCKED IN PLACE
JUST NORTH OF LAKE SUPERIOR THROUGH TUESDAY. WILL SEE RAIN DURING
THE DAY AND A RAIN/SNOW MIX IN THE EVENING...WITH JUST A FEW SHORT
HOURS OF ALL SNOW POSSIBLE LATE EACH NIGHT. NO SNOW ACCUMULATION IS
EXPECTED. MAX AND MIN TEMPS WILL BECOME BELOW NORMAL SATURDAY NIGHT
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 104 AM CDT THU APR 16 2015
VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST. INCREASING AMOUNT
OF MOISTURE MOVING INTO THE NORTHLAND AS HIGH PRESSURE DEPARTS TO
THE EAST...AND AN UPPER LEVEL DISTURBANCE MOVES THROUGH MINNESOTA.
LAST SEVERAL HRRR RUNS SHOW THE BEST CHANCE OF -RA AT KBRD. OTHER
MN TERMINALS MAY SEE VCSH BETWEEN 14Z AND 20Z THIS MORNING...BUT
NOT VERY CONFIDENT THAT MUCH IF ANY WILL REACH THE GROUND AS
LATEST GFS AND NAM SOUNDINGS KEEP THE LOW LEVELS FAIRLY DRY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 38 65 37 57 / 10 0 0 10
INL 33 64 33 61 / 0 10 0 10
BRD 36 67 35 63 / 10 0 0 10
HYR 37 67 38 63 / 10 0 0 10
ASX 37 67 37 58 / 10 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...BJT
LONG TERM...GSF
AVIATION...GROCHOCINSKI/WL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1216 PM CDT THU APR 16 2015
.UPDATE...
ISSUED AT 1215 PM CDT THU APR 16 2015
OBVIOUSLY A VERY TRICKY WEATHER PATTERN WE ARE IN FOR THE NEXT FEW
DAYS AS FAR AS TRYING TO "PINPOINT" PRECIP CHANCES/COVERAGE MORE
THAN A FEW HOURS IN ADVANCE. THE FIRST ROUND OF MODEST...MUCH-
NEEDED RAINFALL OF MAINLY 0.20-0.60-INCH THAT TARGETED MAINLY THE
WESTERN CWA OVERNIGHT HAS FADED AWAY/LIFTED NORTH...LEAVING IN ITS
WAKE A SIZABLE AREA OF ONLY SPOTTY LIGHT SHOWERS/PATCHY DRIZZLE
AND EVEN SOME LEGITIMATE MAINLY LIGHT FOG MAINLY OVER WEST-
CENTRAL ZONES.
GENERALLY...HERE ARE THE EXPECTATIONS FOR THE NEXT 12 HOURS OR
SO:
BASED ON LATEST TRENDS IN SHORT TERM MODELS SUCH AS RAP/HRRR
AND 4KM WRF...THE LACK OF LARGE-SCALE FORCING AND CURRENT LIMITED
INSTABILITY...THE MAJORITY OF THE CWA SHOULD MAKE IT THROUGH THE
MID-LATE AFTERNOON HOURS WITH NOTHING MORE THAN A PASSING LIGHT
SHOWER/SPOTTY DRIZZLE. HOWEVER...AS THE NEXT BATCH OF MODEST MID
LEVEL SHORTWAVE ENERGY KICKS NORTHEAST OUT OF THE NORTHEAST
PERIPHERY OF THE PARENT CLOSED LOW CENTERED WELL-SOUTHWEST NEAR
THE 4-CORNERS...GRADUAL DESTABILIZATION SHOULD LEAD TO INCREASING
COVERAGE OF SHOWERS/THUNDERSTORMS THROUGH THE LATE AFTERNOON AND
ESPECIALLY EVENING. INITIALLY...THE GREATEST COVERAGE AND THREAT
FOR STRONG STORMS/ISOLATED SEVERE WEATHER LOCALLY SHOULD TARGET
THE SOUTHWEST 1/3 OF THE CWA...BUT ESPECIALLY KS ZONES.
HOWEVER...THE "MAIN SHOW" FOR A GREATER RISK OF SEVERE STORMS ON
THE REGIONAL SCALE SHOULD LARGELY FOCUS JUST OUTSIDE THE CWA TO
THE SOUTH AND WEST WITHIN WEST-CENTRAL/SOUTHWEST KS...WHERE THE
PRIMARY SPC SLIGHT/ENHANCED RISK AREAS ARE FOCUSED. WITH
INSTABILITY EVEN WITHIN SOUTHERN PORTIONS OF THE LOCAL AREA (BOTH
LOW-LEVEL AND ELEVATED) CURRENTLY EXPECTED TO ONLY REACH UP TO
AROUND 1000 J/KG IN THE PRESENCE OF DEEP LAYER SHEAR AROUND
30-40KT...COULD EASILY SEE A MIX OF MULTICELL AND SEMI-ORGANIZED
SUPERCELL STRUCTURES...WITH LOW-END SEVERE HAIL/WIND CLEARLY THE
MAIN THREATS. WITH LOW-LEVEL EASTERLY FLOW...FAIRLY LOW LCL
HEIGHTS AND VARIOUS MESOSCALE INTERACTIONS POSSIBLE...AT LEAST A
BRIEF LATE AFTERNOON-EVENING TORNADO IS NOT COMPLETELY OUT OF THE
QUESTION IN SOUTHERN ZONES...BUT AGREE WITH SPC THAT THIS
PROBABILITY IS QUITE LIMITED/MAINLY 2 PERCENT AT MOST...AND THUS
WILL REFRAIN FROM EVEN MENTIONING A TORNADO RISK IN THE HAZARDOUS
WEATHER OUTLOOK UNLESS LATER TRENDS SUGGEST OTHERWISE. WHILE THE
MAIN OPPORTUNITY FOR POSSIBLE SEVERE STORMS WILL LIKELY FOCUS
DURING THE TYPICAL 4PM- MIDNIGHT TIME FRAME...AT LEAST A FEW
STRONGER STORMS COULD LINGER /RE-DEVELOP WELL INTO THE
NIGHT...POSSIBLY IN 1 OR MORE ROUNDS. OF COURSE...TIMING THESE
INDIVIDUAL ROUNDS OF CONVECTION AND THE ASSOCIATED BREAKS IN
BETWEEN WILL BE VERY DIFFICULT. ON A POSITIVE NOTE...THINK A
DECENT CHUNK OF THE CWA WILL PROBABLY SEE NEW RAINFALL AMOUNTS OF
0.50-1.00" (AND LOCALLY HIGHER) BY SUNRISE FRIDAY...ESPECIALLY
SOUTHERN/WESTERN ZONES.
TEMP-WISE TODAY...WHILE MOSTLY CLOUDY SKIES SHOULD REMAIN IN
PLACE MOST AREAS...THERE HAVE ALREADY BEEN DECENT BREAKS IN
OVERCAST IN SOUTHWESTERN ZONES...WHICH HAVE THE BEST CHANCE OF
POSSIBLY BREACHING 70. MEANWHILE...MOST OF THE CWA (ESPECIALLY IN
NEBRASKA) IS STILL EXPECTED TO TOP OUT SOMEWHERE IN THE
60S...ALBEIT BARELY-SO IN SOME SPOTS. MORE TO COME WITH MAIN
AFTERNOON DISCUSSION...
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CDT THU APR 16 2015
RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH
DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS.
SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS
WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA.
AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT
TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW
WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS
BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE
MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST
AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF
THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME
ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING.
HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS
MORNING.
THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING.
THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE
AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE
MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS
THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER
LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 412 AM CDT THU APR 16 2015
A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN
HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR
BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE
FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE
DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL
WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS
CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN
MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION.
WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE
SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE
ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS
BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK
WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT
FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE
REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE
FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN
HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS.
WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG
TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE
AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR
VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH
MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS
ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL
PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD
BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE
SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON.
THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG
COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS
COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE
NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES
CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE
ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES
WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE
IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS
FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY
SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS
ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF
THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND
MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO.
THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER
LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES
ACROSS THE REGION.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1215 PM CDT THU APR 16 2015
THIS WILL A RATHER CHALLENGING PERIOD REGARDING CEILING/VISIBILITY
TRENDS AND ALSO SHOWER/THUNDERSTORM COVERAGE...AND MODIFICATIONS
TO THESE ELEMENTS IN UPCOMING TAF ISSUANCES BOTH ROUTINE ISSUANCE
AND AMENDMENTS ARE LIKELY. BEAR WITH US...
IN GENERAL HOWEVER...AM EXPECTING CURRENT SUB-VFR CEILINGS AND
PATCHY DRIZZLE RIGHT AWAY EARLY THIS AFTERNOON TO LIFT INTO LOW-
END VFR AT SOME POINT THIS AFTERNOON. WHILE AN MVFR/IFR CEILING
CANNOT BE RULED OUT RETURNING AT SOME POINT THIS
EVENING/TONIGHT...WILL HOLD OFF ON THIS MENTION UNTIL THE LATTER
HALF OF THE PERIOD FOR NOW. AS FOR SHOWER/THUNDERSTORM
CHANCES...WHILE PRECIPITATION IS LIKELY ESPECIALLY TONIGHT AT THE
TERMINALS...DO NOT YET HAVE THE CONFIDENCE TO ADVERTISE PREVAILING
SHOWERS/THUNDERSTORMS DURING ANY GIVEN TIME FRAME...AND THUS WILL
CONTINUE TO CARRY EITHER A VICINITY SHOWER (VCSH)/VICINITY
THUNDERSTORM (VCTS) MENTION UNTIL SOMETHING TRULY SHOWS ITS HAND.
FORTUNATELY...SURFACE WIND TRENDS SEEM REASONABLY STRAIGHTFORWARD
(OUTSIDE OF ANY CONVECTIVE ENHANCEMENT/MODIFICATION OF
COURSE)...WITH A GENERALLY EASTERLY DIRECTION PRIMARILY UNDER 12KT
IN PLACE THE MAJORITY OF THE TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...JCB
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
807 AM CDT THU APR 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CDT THU APR 16 2015
RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH
DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS.
SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS
WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA.
AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT
TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW
WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS
BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE
MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST
AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF
THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME
ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING.
HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS
MORNING.
THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING.
THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE
AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE
MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS
THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER
LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 412 AM CDT THU APR 16 2015
A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN
HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR
BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE
FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE
DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL
WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS
CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN
MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION.
WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE
SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE
ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS
BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK
WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT
FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE
REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE
FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN
HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS.
WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG
TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE
AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR
VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH
MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS
ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL
PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD
BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE
SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON.
THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG
COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS
COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE
NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES
CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE
ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES
WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE
IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS
FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY
SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS
ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF
THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND
MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO.
THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER
LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES
ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 806 AM CDT THU APR 16 2015
...UPDATE TO 12Z TAF DISCUSSION...
SINCE THE PREVIOUS DISCUSSION WAS ISSUED A FEW HOURS
AGO...AVIATION CONDITIONS HAVE TAKEN A NOTABLE DOWNWARD TURN WITH
PREVAILING LIFR/IFR CEILING AND IFR/MVFR VISIBILITY IN LOW
STRATUS/LIGHT FOG. THERE IS LIKELY EVEN SOME OFF-AND-ON LIGHT
DRIZZLE ONGOING. IN SHORT...EXPECT A GRADUAL IMPROVEMENT IN
CEILING/VISIBILITY AS THE DAY WEARS ON...BUT SUB-VFR CONDITIONS
MAY LAST LONGER (ESPECIALLY CEILING-WISE) THAN EARLIER THOUGHT.
PRECIPITATION-WISE...THE FIRST 12-15 HOURS SHOULD MAINLY FEATURE
SPOTTY LIGHT SHOWERS/DRIZZLE...WITH A BETTER CHANCE OF ORGANIZED
THUNDERSTORM ACTIVITY ARRIVING THIS EVENING INTO TONIGHT. IN
CLOSING...ANTICIPATE AMENDMENTS TO BE NECESSARY DURING THE PERIOD
AS WE GRADUALLY GET A HANDLE ON SHORT-TERM TRENDS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
548 AM CDT THU APR 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CDT THU APR 16 2015
RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH
DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS.
SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS
WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA.
AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT
TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW
WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS
BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE
MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST
AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF
THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME
ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING.
HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS
MORNING.
THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING.
THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE
AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE
MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS
THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER
LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 412 AM CDT THU APR 16 2015
A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN
HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR
BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE
FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE
DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL
WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS
CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN
MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION.
WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE
SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE
ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS
BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK
WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT
FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE
REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE
FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN
HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS.
WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG
TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE
AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR
VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH
MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS
ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL
PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD
BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE
SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON.
THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG
COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS
COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE
NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES
CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE
ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES
WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE
IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS
FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY
SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS
ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF
THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND
MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO.
THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER
LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES
ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 546 AM CDT THU APR 16 2015
THUNDERSTORMS HAVE MOVED TO THE NORTH OF THE TERMINAL AREAS. THERE
COULD BE A SPRINKLE OR TWO FOR A WHILE BUT THEN THERE COULD BE A
BREAK. THUNDERSTORMS ARE EXPECTED TO REDEVELOP LATER THIS MORNING
OR EARLY THIS AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...ROSSI
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
415 AM CDT THU APR 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CDT THU APR 16 2015
RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING NORTH/NORTHEAST WITH
DEVELOPMENT ON THE SOUTH END OF THE MAIN CLUSTER OF THUNDERSTORMS.
SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM ACROSS WESTERN KANSAS
WITH A COLD FRONT EXTENDING TO THE NORTH ACROSS NEBRASKA.
AN UPPER LEVEL LOW IN THE IN THE FOUR CORNERS REGION WILL DRIFT
TOWARD THE EAST TODAY AND TONIGHT. IN ADVANCE OF THE UPPER LOW A FEW
WAVES WILL MOVE ACROSS THE AREA THROUGH TONIGHT. THE NAM AND GFS
BOTH SPREAD THE PRECIPITATION ACROSS THE FORECAST AREA THROUGH THE
MORNING HOURS AS THE FIRST OF THE WAVES MOVE THROUGH THE FORECAST
AREA. THE RAP AND THE 4KM WRF BOTH INDICATE THIS INITIAL GROUP OF
THUNDERSTORMS WILL MOVE THROUGH AND ALTHOUGH THERE MAY BE SOME
ISOLATED THUNDERSTORMS AROUND...THERE COULD BE A BREAK THIS MORNING.
HAVE KEPT POPS ACROSS THE AREA...BUT DID LOWER THEM A BIT THIS
MORNING.
THE NEXT WAVE WILL MOVE INTO THE AREA THIS AFTERNOON AND EVENING.
THUNDERSTORMS SHOULD DEVELOP IN WESTERN KANSAS AND SPREAD INTO THE
AREA DURING THE AFTERNOON. LATE AFTERNOON INTO THE EARLY EVENING THE
MUCAPE INCREASES TO NEARLY 2500 J/KG MAINLY ACROSS KANSAS. THIS IS
THE AREA WITH THE BEST CHANCE FOR SOME SEVERE WEATHER. ANOTHER UPPER
LEVEL WAVE PUSHES INTO THE AREA LATE TONIGHT. SHOWERS AND
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA LATE TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 412 AM CDT THU APR 16 2015
A PAIR OF UPPER LEVEL LOWS FORECAST TO TRACK ACROSS THE SOUTHERN
HALF OF THE COUNTRY WILL BRING SOME SIGNIFICANT CHANCES FOR
BENEFICIAL RAINFALL TO THE REGION OVER THE NEXT WEEK OR SO. THE
FIRST OF THESE LOW PRESSURE SYSTEMS IS CURRENTLY SPINNING ACROSS THE
DESERT SOUTHWEST...AND ALREADY HAVING AN IMPACT ON THE LOCAL
WEATHER. WITH THIS LOW CUT OFF FROM THE MAIN UPPER LEVEL FLOW ACROSS
CANADA...EXPECT VERY SLOW PROGRESSION TOWARDS THE EAST TO RESULT IN
MULTIPLE DAYS OF UNSETTLED WEATHER ACROSS THE REGION.
WITH MOIST SOUTHERLY FLOW AHEAD OF THIS SYSTEM...DEWPOINTS HAVE
SURGED INTO THE 50S ACROSS MUCH OF THE LOCAL AREA AND EXPECT THE
ASSOCIATED INSTABILITY TO HELP AID IN THE FORMATION OF THUNDERSTORMS
BOTH FRIDAY AND SATURDAY. THAT SAID...WITH MUCH BETTER SHEAR TO WORK
WITH ON FRIDAY AFTERNOON/EVENING...THIS APPEARS TO BE THE BEST SHOT
FOR MORE WIDESPREAD STRONG AND POTENTIALLY SEVERE STORMS ACROSS THE
REGION...AND NOT SURPRISINGLY ROUGHLY THE SOUTHERN HALF OF THE
FORECAST AREA IS NOW OUTLOOKED BY SPC. IF REALIZED...THE MAIN
HAZARDS ARE LIKELY TO BE LARGE HAIL AND STRONG WIND GUSTS.
WHILE STILL NOT OUT OF THE QUESTION FOR SATURDAY...ADDITIONAL STRONG
TO MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE DURING THE
AFTERNOON AND EVENING HOURS...BUT DUE TO DIMINISHED SHEAR
VALUES...THINK THE COVERAGE OF THESE STRONGER STORMS WILL BE MUCH
MORE LIMITED. EVEN SO...WIDESPREAD BENEFICIAL RAINFALL IS
ANTICIPATED FOR THE ENTIRE REGION BOTH DAYS...WITH STORM TOTAL
PRECIPITATION AMOUNTS OVER 2 INCHES EXPECTED TO BE FAIRLY WIDESPREAD
BY THE TIME THE RAINFALL ENDS AND THE RESPONSIBLE LOW PRESSURE
SYSTEM TRACKS EASTWARDS SUNDAY AFTERNOON.
THIS LOW PRESSURE SYSTEM WILL BE SHIFTED EASTWARD BY A FAIRLY STRONG
COLD FRONT FORECAST TO DROP SOUTH ACROSS THE LOCAL AREA SUNDAY. THIS
COLD FRONT WILL BRING SIGNIFICANTLY COOLER TEMPERATURES TO START THE
NEW WORK WEEK WITH POTENTIALLY SOME NEAR FREEZING TEMPERATURES
CURRENTLY FORECAST FOR BOTH MONDAY AND TUESDAY MORNINGS. WHILE
ACTUAL FROST MAY NOT DEVELOP EITHER DAY...THESE COOLER TEMPERATURES
WILL BE SOMETHING TO MONITOR AS SENSITIVE VEGETATION MAY BE
IMPACTED. ADDITIONALLY...WITH STRONG NORTHWESTERLY WINDS BEHIND THIS
FRONT AND DRIER AIR ADVECTING IN FROM THE NORTH...COULD EVENTUALLY
SEE SOME NEAR CRITICAL FIRE WEATHER CONDITIONS REALIZED ACROSS
ROUGHLY THE NORTHWESTERN HALF OF THE LOCAL AREA. BECAUSE BOTH OF
THESE POTENTIAL HAZARDS ARE STILL SEVERAL DAYS OUT AND
MARGINAL...OPTED NOT TO MENTION EITHER OF THESE IN THE MORNING HWO.
THEREAFTER...RAINFALL CHANCES WILL INCREASE MIDWEEK AS ANOTHER UPPER
LEVEL LOW MOVES INTO THE DESERT SOUTHWEST AND MOISTURE INCREASES
ACROSS THE REGION.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1225 AM CDT THU APR 16 2015
THUNDERSTORMS ARE GRADUALLY MOVING IN FROM THE WEST. THUNDERSTORMS
ARE EXPECTED ON AND OFF THROUGH MUCH OF THE DAY. THE SURFACE LOW
TO THE SOUTHWEST WILL KEEP WINDS FROM THE EAST OR SOUTHEAST
THROUGH THE PERIOD. THE LOWEST CEILINGS WILL BE BEFORE SUNRISE
THIS MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...ROSSI
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1150 PM CDT WED APR 15 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 309 PM CDT WED APR 15 2015
LARGE SCALE PATTERN PER WV IMAGERY THIS AFTN SHOWING FAST ZONAL FLOW
WITH SEVERAL EMBEDDED WAVES EXTENDING ACROSS SRN CANADA WITH A LARGE
CLOSED OFF CIRCULATION SITUATED OVER THE GREAT BASIN. AT THE
SFC...LLVL MOISTURE RETURN IS UNDERWAY WITH DEW POINTS INCREASING
OVER THE LOWER/MID MS VLY REGION. RUC13 SHOWING BNDRY LYR MOISTURE
ADV CONTINUING THRU TONIGHT WITH PW VALUES INCREASING TO AROUND AN
INCH OVER THE CWA. TSTM DEVELOPMENT PROGGED TO OCCUR OVER CNTRL KS/S-
CNTRL NEB LATER THIS EVENING WITHIN AREA OF ELEVATED
INSTABILITY/NOSE OF LLVL JET...THEN EXPAND NEWD INTO THE WRN CWA
SOMETIME AFT MIDNIGHT AS UPGLIDE INCREASES ALONG 300K SFC. PLAN ON
ONLY MAKING MINOR TWEAKS AT THIS POINT AS GOING FCST IS IN DECENT
SHAPE DEPICTING POPS INCREASING FROM WEST TO EAST DURING THE
OVERNIGHT HOURS.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 309 PM CDT WED APR 15 2015
MAIN FORECAST CONCERN WILL BE PROGRESSION OF WESTERN CONUS UPPER LOW
AND ITS IMPACTS AS IT SLIDE ACROSS THE CENTRAL PLAINS.
BY THURSDAY MORNING...THE WESTERN CONUS UPPER LOW WILL BE CENTERED
ON TOP OF THE FOUR CORNERS REGION. LEE SIDE SFC LOW REFLECTION IS
FORECAST TO BE FAIRLY BROAD ACROSS THE TEXAS PANHANDLE WITH AN
INVERTED TROUGH EXTENDING NORTHEAST ACROSS WESTERN KS AND INTO
WESTERN NEBRASKA. PRECIPITATION WILL CONTINUE TO SPREAD EAST INTO
OUR WESTERN CWA...BECOMING LIKELY LATER IN THE DAY THURSDAY AS
BROAD SCALE ASCENT INCREASES WITH LEAD SHORTWAVE ENERGY. THE UPPER
LOW WILL SLOWLY MOVE INTO THE SOUTHERN PLAINS AND IS FORECAST TO
OPEN UP THROUGH THE WEEKEND PROVIDING CONTINUED BROAD SCALE
VERTICAL MOTION THROUGH SUNDAY. LOW LEVEL MOISTURE ALREADY IN
PLACE ACROSS THE SOUTHERN PLAINS WILL CONTINUE TO STREAM NORTHWARD
AS THE SFC LOW PRESSURE CENTER BETTER ORGANIZES ACROSS EASTERN
COLORADO BY FRIDAY MORNING. PW`S WILL REMAIN ABOVE 1" THROUGH THE
PERIOD. ALTHOUGH RAIN IS LIKELY AT TIMES THROUGH SUNDAY...WE WILL
HAVE A FEW INTERMITTENT BREAKS BUT TOO DIFFICULT TO DETERMINE AT
THIS POINT WITH SUCH SLOW PROGRESSION OF THE UPPER LOW. BEST
CHANCE FOR THUNDERSTORMS LOOKS TO BE THURSDAY AND FRIDAY
AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN CWA. HAVE INCLUDED
ISOLATED THUNDER MENTION THROUGH MUCH OF THE TIME PERIOD.
BY MID DAY SUNDAY...THE UPPER TROUGH AXIS SHOULD BE EAST OF THE
CWA...ALLOWING PCPN TO END FROM WEST TO EAST. THE 12Z ECMWF REALLY
WRAPS THIS SYSTEM UP...WITH NORTHWESTERLY 850MB WINDS ON THE
ORDER OF 65KTS SUNDAY AFTERNOON. 850MB TEMPERATURES DO APPROACH
THE 0C MARK OF THE LATEST ECMWF SO WILL NEED TO WATCH THAT
CAREFULLY FOR ANY CHANGE OVER IN PCPN TYPES SUNDAY.
MUCH COOLER NORTHWESTERLY FLOW WILL PERSIST ACROSS THE AREA THROUGH
EARLY NEXT WEEK WHICH MAY PUT TEMPERATURES INTO THE BELOW NORMAL
CATEGORY. A FEW MINOR WAVES MAY MOVE THROUGH THIS FLOW PROVIDING
SMALL CHANCES FOR PCPN.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1146 PM CDT WED APR 15 2015
GENERALLY MVFR CIGS ARE EXPECTED OVERNIGHT AT THE TAF SITES. THE
BNK-OVC DECKS SHOULD CONT THROUGH THE DAY ON THU AS WELL BUT
INCREASE TO VFR /FL0040-050/ BY MID TO LATE MRNG. WE WILL CONT TO
LEAVE THE TAFS DRY AT THE MOMENT AS PRECIP TIMING AND CONFIDENCE
IS PRETTY LOW AT THIS POINT. IT WOULD APPEAR THAT THERE COULD BE
SOME MRNG SHRA AT KLNK...AND THEN SOME ISO LATE AFTN -SHRA AT ALL
SITES BUT COVERAGE IS EXPECTED TO BE LOW. OTHERWISE SOUTHEAST
WINDS...GENERALLY BELOW 12 KT...WILL CONT THROUGH THU EVNG.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE
LONG TERM...KERN
AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1038 PM EDT FRI APR 17 2015
.SYNOPSIS...
HIGH PRESSURE WILL BRING CLEARING SKIES TONIGHT. A COLD FRONT WILL
MOVE ACROSS THE REGION ON SATURDAY...HOWEVER THE FRONT IS MOISTURE
STARVED SO MOST AREAS WILL REMAIN MOSTLY SUNNY AND BREEZY. A FEW
SCATTERED LIGHT SHOWERS ARE POSSIBLE ACROSS THE NORTH COUNTRY WHERE
A LITTLE MORE MOISTURE IS AVAILABLE. HIGH PRESSURE WILL BRING A
RETURN TO DRY WEATHER FOR SUNDAY. LOW PRESSURE WILL MOVE THROUGH THE
GREAT LAKES SUNDAY NIGHT AND MONDAY WITH OCCASIONAL SHOWERS AND
GUSTY WINDS. UNSETTLED AND COOL WEATHER IS THEN EXPECTED MOST OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
THE 00Z BUF SOUNDINGS SHOWS A NICELY ESTABLISHED MARINE LAYER WITH A
SHARP INVERSION ABOVE 700 FEET AGL. THIS INVERSION SHOULD KEEP A
TIGHT CAP ON THE MARINE MOISTURE OFF THE LAKES...AND AS
SOUTHWESTERLY WINDS INCREASE AGAIN LATER TONIGHT...SHOULD SUPPORT
ANOTHER ROUND OF FOG FOR THE BUFFALO AND WATERTOWN AREAS AFTER
MIDNIGHT. NAM/SREF/GFS BUFKIT SOUNDINGS PICK UP ON THIS INVERSION
NICELY...AND SHOW SUPPORT FOR FOG DEVELOPING OVER THE LAKES AFTER
MIDNIGHT AND ADVECTING INLAND. BY TOMORROW MORNING...THE APPROACHING
COLD FRONT WILL GIVE THE FORCING NEEDED TO FINALLY BREAK THIS UP
THIS MARINE LAYER AND SCOUR OUT ANY FOG THAT REDEVELOPS OVERNIGHT.
IN FACT...THE HRRR PICKS UP NICELY ON A PERIOD OF CLEARING FOR
BUFFALO THIS EVENING...BEFORE ADVECTING FOG DOWN THE LAKE AND INTO
THE BUFFALO/NIAGARA FALLS AREAS ON A SOUTHWESTERLY TO
SOUTH-SOUTHWESTERLY FLOW.
A WEAK BUBBLE OF HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY
TONIGHT WITH A RIDGE EXTENDING INTO THE LOWER LAKES. SUBSIDENCE AND
DRYING ASSOCIATED WITH THIS HIGH WILL FINISH THE CLEARING PROCESS
TONIGHT AND SUPPORT CLEAR SKIES OVERNIGHT. EXPECT LOWS IN THE LOWER
40S IN MOST LOCATIONS WITH MID TO UPPER 30S IN THE COOLEST SOUTHERN
TIER VALLEYS AND NORTH COUNTRY.
ON SATURDAY A POTENT MID LEVEL SHORTWAVE AND ASSOCIATED WEAK SURFACE
LOW WILL CROSS QUEBEC AND NEW ENGLAND. A TRAILING SURFACE COLD FRONT
WILL CROSS OUR REGION DURING THE LATE MORNING. DESPITE THE STRONG
ASCENT WITH THE SHORTWAVE...THE FRONT WILL BE MOISTURE STARVED WITH
LITTLE EVEN IN THE WAY OF CLOUD COVER FOR THE BULK OF THE AREA. THE
STRONGEST FORCING AND SOMEWHAT BETTER MOISTURE WILL CLIP THE NORTH
COUNTRY WHERE A FEW SPRINKLES OR LIGHT SHOWERS ARE POSSIBLE FROM MID
MORNING THROUGH MID AFTERNOON ALONG WITH MORE CLOUD COVER. THE REST
OF THE AREA SHOULD REMAIN MOSTLY SUNNY.
NORTHWEST WINDS WILL BECOME A LITTLE GUSTY BEHIND THE COLD FRONT
SATURDAY AFTERNOON...WITH GUSTS IN THE 30-35 MPH RANGE ESPECIALLY
ACROSS THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER...FINGER
LAKES...AND NORTH COUNTRY. DESPITE THE COLD FRONTAL PASSAGE...DEEP
MIXING AND SUNSHINE WILL BOOST HIGHS INTO THE MID 60S IN MOST AREAS
WITH UPPER 50S TO LOWER 60S NORTH COUNTRY. GRADIENT ONSHORE FLOW
WILL KEEP THE LAKE ERIE AND ONTARIO SHORES COOLER.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
SATURDAY NIGHT THROUGH MOST OF SUNDAY QUIET WEATHER CONDITIONS ARE
EXPECTED ACROSS THE REGION AS HIGH PRESSURE ADVANCES ACROSS SOUTHERN
QUEBEC.
THROUGH THE COURSE OF SUNDAY MID AND HIGH LEVEL CLOUDS WILL BE
INCREASING FROM WEST TO EAST ACROSS NEW YORK STATE...THESE CLOUDS
ARE IN ADVANCE OF A WARM FRONT THAT WILL BE LIFTING NORTHWARD ACROSS
THE OHIO VALLEY. THIS WARM FRONT WILL BE CONNECTED TO AN AREA OF LOW
PRESSURE THAT WILL LIFT NORTHWARD FROM WESTERN KENTUCKY SUNDAY TO
NORTHERN MICHIGAN MONDAY MORNING.
GULF MOISTURE WILL INCREASE ACROSS THE EASTERN GREAT LAKES REGION
LATE SUNDAY AFTERNOON AND SUNDAY NIGHT AS THE WARM FRONT FROM THE SOUTH
REACHES WESTERN NEW YORK. STRONG LOW LEVEL CONVERGENCE FROM A 65 TO
70 KNOT LLJ CENTERED NEAR 850 TO 900 HPA WILL BRING LIFT ACROSS THE
WARM FRONT...SUCH THAT WIDESPREAD RAIN FALL UPON THE REGION SUNDAY
NIGHT. A QUARTER TO HALF INCH OF RAINFALL IS EXPECTED SUNDAY NIGHT
AND INTO MONDAY MORNING FROM THIS SYSTEM.
WINDS WILL ALSO BECOME GUSTY LATER SUNDAY NIGHT ALONG THE LAKE ERIE
SHORE...WHERE A SE LLJ ALOFT BRINGS SURFACE GUSTS 30 TO 40 KNOTS
ALONG THE SHORELINE. AS THE WARM FRONT AND ASSOCIATED RAIN LIFTS
NORTHWARD OUT OF THE REGION MONDAY...THERE IS THE POTENTIAL FOR
LIMITED SUNSHINE ALONG WITH A BRIEF WINDOW OF RAINFREE CONDITIONS.
WITH THE LLJ STILL OVERHEAD...ANY SUNSHINE WILL INCREASE THE MIXING
HEIGHTS SUCH THAT WE COULD TAP INTO THIS LLJ...WITH WIND GUSTS
MONDAY ALSO 30 TO 35 KNOTS ACROSS WESTERN AND NORTH CENTRAL NEW
YORK.
LATER MONDAY AFTERNOON CLOUDS WILL THICKEN FROM WEST TO EAST...AND A
DECREASE IN THE GUSTY WINDS IS EXPECTED. A COLD FRONT FROM THIS
CENTRAL LAKES STORM SYSTEM WILL NEAR WESTERN NEW YORK LATE MONDAY
AFTERNOON. ANOTHER ROUND OF RAIN SHOWERS IS EXPECTED MONDAY
AFTERNOON AND MONDAY NIGHT ALONG AND AHEAD OF THE COLD FRONT.
ANOTHER RAINFALL EVENT AVERAGING AROUND A QUARTER OF AN INCH IS EXPECTED.
RAINFALL VALUES MAY RANGE GREATER WITH THE COLD FRONT PASSAGE THAN
THE EARLIER WARM FRONT DUE TO THE CONVECTIVE NATURE OF THE RAIN
SHOWERS. MID LEVEL LAPSE RATES ARE NOT PARTICULARLY STRONG AND WITH
THE OVERNIGHT PASSAGE OF THE COLD FRONT FOR NOW WILL NOT INCLUDE ANY
MENTION OF THUNDER WITH THIS FORECAST PACKAGE...EVEN THROUGH THERE
IS SOME SKINNY MID LEVEL CAPE.
THE WARMEST DAY THIS PERIOD WILL BE MONDAY WHEN BEFORE THE COLD
FRONT 850 HPA TEMPERATURES WILL SURGE TO +7 TO +10C. THESE READINGS
WILL SUPPORT HIGHS IN THE 60S...WITH 70S POSSIBLE ACROSS LOWER
ELEVATIONS ON A SOUTHEAST WIND.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
CLASSIC SPRING-TIME PATTERN THIS TIME PERIOD AS A DEVELOPING NEGATIVE
NAO ALLOWS FOR A UPPER LEVEL CUT OFF LOW TO STALL OVER EASTERN
CANADA AND THE NORTHEAST UNITED STATES. UNDER THIS LOW PRESSURE
EXPECT CLOUDY DAYS WITH SCATTERED RAIN SHOWERS. RAIN SHOWER ACTIVITY
WILL BE MOST PRONOUNCED IN THE AFTERNOON HOURS WITH DAYTIME
HEATING...WITH FEW SHOWERS TO BE FOUND BY NIGHT. THERE MAY EVEN BE
SOME WET SNOW MIXING IN AT NIGHT ACROSS THE REGION. DAYTIME AIR
TEMPERATURES WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AFTER MIDNIGHT...MOISTURE TRAPPED UNDER A SHARP INVERSION WILL BE
ENHANCED BY LAKES ERIE AND ONTARIO. SOUTHWEST TO SOUTH-SOUTHWESTERLY
WINDS COULD BRING SOME AREAS OF FOG INTO THE KBUF/KIAG/KART
TERMINALS...HOWEVER FORECAST CONFIDENCE IN THE INLAND EXTENT OF THIS
FOG TO THE TERMINALS REMAINS LOW. OUTSIDE OF THE POTENTIAL FOR
FOG...MAINLY VFR CONDITIONS WITH CLEAR SKIES AND LIGHT WINDS WILL
PREVAIL ACROSS THE TAF SITES.
ON SATURDAY A MOISTURE STARVED SHARP MID LEVEL DISTURBANCE AND COLD
FRONT WILL CROSS THE REGION. THE STRONGEST ASCENT WILL CROSS THE
NORTH COUNTRY WITH INCREASING CLOUDS AND POSSIBLY A FEW LIGHT
SHOWERS FROM MID MORNING THROUGH MID AFTERNOON. CIGS AND VSBY WILL
REMAIN VFR WITH THIS GIVEN THE DRY LOW LEVELS. FOR THE REST OF THE
AREA JUST EXPECT A SHIFT IN WIND DIRECTION AND INCREASE IN SPEED
WITH THE FRONTAL PASSAGE AND JUST A FEW SCATTERED CLOUDS.
OUTLOOK...
SUNDAY...VFR.
SUNDAY NIGHT AND MONDAY...AREAS OF MVFR WITH OCCASIONAL SHOWERS AND
GUSTY WINDS.
TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
RELATIVELY LIGHT WINDS WILL CONTINUE ON THE LOWER LAKES THROUGH
TONIGHT AS A WEAK RIDGE OF HIGH PRESSURE BRIEFLY BUILDS ACROSS THE
OHIO VALLEY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE AREA
SATURDAY MORNING. NORTHWEST WINDS WILL INCREASE IN THE WAKE OF THE
COLD FRONT AND PRODUCE CHOPPY WAVES IN THE AFTERNOON ESPECIALLY ON
LAKE ONTARIO...BUT CONDITIONS ARE EXPECTED TO REMAIN JUST BELOW
SMALL CRAFT ADVISORY CRITERIA. THE STRONGEST WINDS WILL BE FOUND
ACROSS THE SAINT LAWRENCE VALLEY WHERE 20-25 KNOTS SUSTAINED ARE
EXPECTED DURING THE AFTERNOON. WITH THIS IN MIND...WE HAVE ISSUED A
SHORT LIVED SMALL CRAFT ADVISORY FOR SATURDAY AFTERNOON FOR THE
SAINT LAWRENCE RIVER.
LIGHTER WINDS WILL RETURN FOR SUNDAY AS HIGH PRESSURE BUILDS ACROSS
QUEBEC. A FAIRLY STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH THE
CENTRAL LAKES LATER SUNDAY NIGHT AND MONDAY AND BRING AN INCREASE IN
WINDS AND POTENTIAL SMALL CRAFT ADVISORY CONDITIONS TO THE LOWER
LAKES.
&&
.FIRE WEATHER...
NEAR RED FLAG CONDITIONS ARE EXPECTED ON SATURDAY AFTERNOON.
A COLD FRONT WILL MOVE ACROSS THE REGION LATE SATURDAY MORNING.
BEHIND THE COLD FRONT WINDS WILL INCREASE OUT OF THE NORTHWEST WITH
SUSTAINED WINDS OF 20-25 MPH AND GUSTS OF 30-35 MPH ESPECIALLY
ACROSS THE NORTH COUNTRY AND THE HIGHER TERRAIN OF THE INTERIOR
SOUTHERN TIER AND FINGER LAKES. RH WILL ALSO DROP DURING THE
AFTERNOON FROM A COMBINATION OF DIURNAL WARMING AND DRY ADVECTION
BEHIND THE COLD FRONT. THIS WILL DROP RH TO AROUND 25 PERCENT IN
MANY AREAS AWAY FROM THE LAKESHORES DURING THE AFTERNOON.
WIND AND RH WILL APPROACH RED FLAG CRITERIA...HOWEVER THE BULK OF
THE AREA HAD A QUARTER INCH OR MORE OF RAIN LAST NIGHT. THE RECENT
RAINFALL MAKES FINE FUELS WETTER...AND TAKES OUR REGION OUT OF RED
FLAG CRITERIA. THE ONLY LOCATION WHICH RECEIVED LOWER RAIN AMOUNTS
IS THE NORTH COUNTRY...HOWEVER SNOW ACROSS THE HIGHER TERRAIN OF
THE TUG HILL AND WESTERN ADIRONDACKS HAS JUST MELTED IN THE PAST
DAY OR TWO...SO FINE FUELS ACROSS MANY OF THESE AREAS ARE LIKELY
STILL TOO WET TO JUSTIFY ANY FIRE WEATHER HEADLINES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 8 PM EDT SATURDAY FOR SLZ022-
024.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...CHURCH/HITCHCOCK
MARINE...HITCHCOCK
FIRE WEATHER...HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
759 PM EDT FRI APR 17 2015
.SYNOPSIS...
HIGH PRESSURE WILL BRING CLEARING SKIES TONIGHT. A COLD FRONT WILL
MOVE ACROSS THE REGION ON SATURDAY...HOWEVER THE FRONT IS MOISTURE
STARVED SO MOST AREAS WILL REMAIN MOSTLY SUNNY AND BREEZY. A FEW
SCATTERED LIGHT SHOWERS ARE POSSIBLE ACROSS THE NORTH COUNTRY WHERE
A LITTLE MORE MOISTURE IS AVAILABLE. HIGH PRESSURE WILL BRING A
RETURN TO DRY WEATHER FOR SUNDAY. LOW PRESSURE WILL MOVE THROUGH THE
GREAT LAKES SUNDAY NIGHT AND MONDAY WITH OCCASIONAL SHOWERS AND
GUSTY WINDS. UNSETTLED AND COOL WEATHER IS THEN EXPECTED MOST OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
DRIER AIR ADVECTING INTO THE REGION OUT OF SOUTHERN ONTARIO IS
FINALLY ALLOWING THE STUBBORN LOW STRATUS TO ERODE IN MOST AREAS.
MOIST AIR CROSSING THE COLD LAKES WILL CONTINUE TO PRODUCE SOME
LOCAL LOW STRATUS AND FOG THROUGH EARLY EVENING EAST OF LAKES ERIE
AND ONTARIO. VISIBLE SATELLITE SHOWS CLEARING FROM WEST TO EAST
ACROSS EASTERN LAKE ERIE THIS EVENING...AND THUS SUSPECT DOWNTOWN
BUFFALO WILL SEE A PERIOD OF CLEARING FOR SEVERAL HOURS THIS
EVENING. HOWEVER...THE 00Z BUF SOUNDINGS SHOWS A NICELY ESTABLISHED
MARINE LAYER WITH A SHARP INVERSION ABOVE 700 FEET AGL. THIS
INVERSION SHOULD KEEP A TIGHT CAP ON THE MARINE MOISTURE OFF THE
LAKES...AND AS SOUTHWESTERLY WINDS INCREASE AGAIN LATER
TONIGHT...SHOULD SUPPORT ANOTHER ROUND OF FOG FOR THE BUFFALO AND
WATERTOWN AREAS AFTER MIDNIGHT. NAM/SREF/GFS BUFKIT SOUNDINGS PICK
UP ON THIS INVERSION NICELY...AND SHOW SUPPORT FOR FOG DEVELOPING
OVER THE LAKES AFTER MIDNIGHT AND ADVECTING INLAND. BY TOMORROW
MORNING...THE APPROACHING COLD FRONT WILL GIVE THE FORCING NEEDED TO
FINALLY BREAK THIS UP THIS MARINE LAYER AND SCOUR OUT ANY FOG THAT
REDEVELOPS OVERNIGHT. IN FACT...THE HRRR PICKS UP NICELY ON A PERIOD
OF CLEARING FOR BUFFALO THIS EVENING...BEFORE ADVECTING FOG DOWN THE
LAKE AND INTO THE BUFFALO/NIAGARA FALLS AREAS ON A SOUTHWESTERLY TO
SOUTH-SOUTHWESTERLY FLOW.
A WEAK BUBBLE OF HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY
TONIGHT WITH A RIDGE EXTENDING INTO THE LOWER LAKES. SUBSIDENCE AND
DRYING ASSOCIATED WITH THIS HIGH WILL FINISH THE CLEARING PROCESS
TONIGHT AND SUPPORT CLEAR SKIES OVERNIGHT. EXPECT LOWS IN THE LOWER
40S IN MOST LOCATIONS WITH MID TO UPPER 30S IN THE COOLEST SOUTHERN
TIER VALLEYS AND NORTH COUNTRY.
ON SATURDAY A POTENT MID LEVEL SHORTWAVE AND ASSOCIATED WEAK SURFACE
LOW WILL CROSS QUEBEC AND NEW ENGLAND. A TRAILING SURFACE COLD FRONT
WILL CROSS OUR REGION DURING THE LATE MORNING. DESPITE THE STRONG
ASCENT WITH THE SHORTWAVE...THE FRONT WILL BE MOISTURE STARVED WITH
LITTLE EVEN IN THE WAY OF CLOUD COVER FOR THE BULK OF THE AREA. THE
STRONGEST FORCING AND SOMEWHAT BETTER MOISTURE WILL CLIP THE NORTH
COUNTRY WHERE A FEW SPRINKLES OR LIGHT SHOWERS ARE POSSIBLE FROM MID
MORNING THROUGH MID AFTERNOON ALONG WITH MORE CLOUD COVER. THE REST
OF THE AREA SHOULD REMAIN MOSTLY SUNNY.
NORTHWEST WINDS WILL BECOME A LITTLE GUSTY BEHIND THE COLD FRONT
SATURDAY AFTERNOON...WITH GUSTS IN THE 30-35 MPH RANGE ESPECIALLY
ACROSS THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER...FINGER
LAKES...AND NORTH COUNTRY. DESPITE THE COLD FRONTAL PASSAGE...DEEP
MIXING AND SUNSHINE WILL BOOST HIGHS INTO THE MID 60S IN MOST AREAS
WITH UPPER 50S TO LOWER 60S NORTH COUNTRY. GRADIENT ONSHORE FLOW
WILL KEEP THE LAKE ERIE AND ONTARIO SHORES COOLER.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
SATURDAY NIGHT THROUGH MOST OF SUNDAY QUIET WEATHER CONDITIONS ARE
EXPECTED ACROSS THE REGION AS HIGH PRESSURE ADVANCES ACROSS SOUTHERN
QUEBEC.
THROUGH THE COURSE OF SUNDAY MID AND HIGH LEVEL CLOUDS WILL BE
INCREASING FROM WEST TO EAST ACROSS NEW YORK STATE...THESE CLOUDS
ARE IN ADVANCE OF A WARM FRONT THAT WILL BE LIFTING NORTHWARD ACROSS
THE OHIO VALLEY. THIS WARM FRONT WILL BE CONNECTED TO AN AREA OF LOW
PRESSURE THAT WILL LIFT NORTHWARD FROM WESTERN KENTUCKY SUNDAY TO
NORTHERN MICHIGAN MONDAY MORNING.
GULF MOISTURE WILL INCREASE ACROSS THE EASTERN GREAT LAKES REGION
LATE SUNDAY AFTERNOON AND SUNDAY NIGHT AS THE WARM FRONT FROM THE SOUTH
REACHES WESTERN NEW YORK. STRONG LOW LEVEL CONVERGENCE FROM A 65 TO
70 KNOT LLJ CENTERED NEAR 850 TO 900 HPA WILL BRING LIFT ACROSS THE
WARM FRONT...SUCH THAT WIDESPREAD RAIN FALL UPON THE REGION SUNDAY
NIGHT. A QUARTER TO HALF INCH OF RAINFALL IS EXPECTED SUNDAY NIGHT
AND INTO MONDAY MORNING FROM THIS SYSTEM.
WINDS WILL ALSO BECOME GUSTY LATER SUNDAY NIGHT ALONG THE LAKE ERIE
SHORE...WHERE A SE LLJ ALOFT BRINGS SURFACE GUSTS 30 TO 40 KNOTS
ALONG THE SHORELINE. AS THE WARM FRONT AND ASSOCIATED RAIN LIFTS
NORTHWARD OUT OF THE REGION MONDAY...THERE IS THE POTENTIAL FOR
LIMITED SUNSHINE ALONG WITH A BRIEF WINDOW OF RAINFREE CONDITIONS.
WITH THE LLJ STILL OVERHEAD...ANY SUNSHINE WILL INCREASE THE MIXING
HEIGHTS SUCH THAT WE COULD TAP INTO THIS LLJ...WITH WIND GUSTS
MONDAY ALSO 30 TO 35 KNOTS ACROSS WESTERN AND NORTH CENTRAL NEW
YORK.
LATER MONDAY AFTERNOON CLOUDS WILL THICKEN FROM WEST TO EAST...AND A
DECREASE IN THE GUSTY WINDS IS EXPECTED. A COLD FRONT FROM THIS
CENTRAL LAKES STORM SYSTEM WILL NEAR WESTERN NEW YORK LATE MONDAY
AFTERNOON. ANOTHER ROUND OF RAIN SHOWERS IS EXPECTED MONDAY
AFTERNOON AND MONDAY NIGHT ALONG AND AHEAD OF THE COLD FRONT.
ANOTHER RAINFALL EVENT AVERAGING AROUND A QUARTER OF AN INCH IS EXPECTED.
RAINFALL VALUES MAY RANGE GREATER WITH THE COLD FRONT PASSAGE THAN
THE EARLIER WARM FRONT DUE TO THE CONVECTIVE NATURE OF THE RAIN
SHOWERS. MID LEVEL LAPSE RATES ARE NOT PARTICULARLY STRONG AND WITH
THE OVERNIGHT PASSAGE OF THE COLD FRONT FOR NOW WILL NOT INCLUDE ANY
MENTION OF THUNDER WITH THIS FORECAST PACKAGE...EVEN THROUGH THERE
IS SOME SKINNY MID LEVEL CAPE.
THE WARMEST DAY THIS PERIOD WILL BE MONDAY WHEN BEFORE THE COLD
FRONT 850 HPA TEMPERATURES WILL SURGE TO +7 TO +10C. THESE READINGS
WILL SUPPORT HIGHS IN THE 60S...WITH 70S POSSIBLE ACROSS LOWER
ELEVATIONS ON A SOUTHEAST WIND.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
CLASSIC SPRING-TIME PATTERN THIS TIME PERIOD AS A DEVELOPING NEGATIVE
NAO ALLOWS FOR A UPPER LEVEL CUT OFF LOW TO STALL OVER EASTERN
CANADA AND THE NORTHEAST UNITED STATES. UNDER THIS LOW PRESSURE
EXPECT CLOUDY DAYS WITH SCATTERED RAIN SHOWERS. RAIN SHOWER ACTIVITY
WILL BE MOST PRONOUNCED IN THE AFTERNOON HOURS WITH DAYTIME
HEATING...WITH FEW SHOWERS TO BE FOUND BY NIGHT. THERE MAY EVEN BE
SOME WET SNOW MIXING IN AT NIGHT ACROSS THE REGION. DAYTIME AIR
TEMPERATURES WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THIS EVENING WITH HIGH
PRESSURE BUILDING. SOME FOG WILL PERSIST NEAR THE LAKE SHORES EARLY
THIS EVENING...BUT SHOULD BREAK UP WITH SOME DRIER AIR MOVING IN.
THEN AFTER MIDNIGHT...MOISTURE TRAPPED UNDER A SHARP INVERSION WILL
BE ENHANCED BY LAKES ERIE AND ONTARIO. SOUTHWEST TO
SOUTH-SOUTHWESTERLY WINDS COULD BRING SOME AREAS OF FOG INTO THE
KBUF/KIAG/KART TERMINALS...HOWEVER FORECAST CONFIDENCE IN THE INLAND
EXTENT OF THIS FOG TO THE TERMINALS REMAINS LOW.
ON SATURDAY A MOISTURE STARVED SHARP MID LEVEL DISTURBANCE AND COLD
FRONT WILL CROSS THE REGION. THE STRONGEST ASCENT WILL CROSS THE
NORTH COUNTRY WITH INCREASING CLOUDS AND POSSIBLY A FEW LIGHT
SHOWERS FROM MID MORNING THROUGH MID AFTERNOON. CIGS AND VSBY WILL
REMAIN VFR WITH THIS GIVEN THE DRY LOW LEVELS. FOR THE REST OF THE
AREA JUST EXPECT A SHIFT IN WIND DIRECTION AND INCREASE IN SPEED
WITH THE FRONTAL PASSAGE AND JUST A FEW SCATTERED CLOUDS.
OUTLOOK...
SUNDAY...VFR.
SUNDAY NIGHT AND MONDAY...AREAS OF MVFR WITH OCCASIONAL SHOWERS AND
GUSTY WINDS.
TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
RELATIVELY LIGHT WINDS WILL CONTINUE ON THE LOWER LAKES THROUGH
TONIGHT AS A WEAK RIDGE OF HIGH PRESSURE BRIEFLY BUILDS ACROSS THE
OHIO VALLEY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE AREA
SATURDAY MORNING. NORTHWEST WINDS WILL INCREASE IN THE WAKE OF THE
COLD FRONT AND PRODUCE CHOPPY WAVES IN THE AFTERNOON ESPECIALLY ON
LAKE ONTARIO...BUT CONDITIONS ARE EXPECTED TO REMAIN JUST BELOW
SMALL CRAFT ADVISORY CRITERIA. THE STRONGEST WINDS WILL BE FOUND
ACROSS THE SAINT LAWRENCE VALLEY WHERE 20-25 KNOTS SUSTAINED ARE
EXPECTED DURING THE AFTERNOON. WITH THIS IN MIND...WE HAVE ISSUED A
SHORT LIVED SMALL CRAFT ADVISORY FOR SATURDAY AFTERNOON FOR THE
SAINT LAWRENCE RIVER.
LIGHTER WINDS WILL RETURN FOR SUNDAY AS HIGH PRESSURE BUILDS ACROSS
QUEBEC. A FAIRLY STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH THE
CENTRAL LAKES LATER SUNDAY NIGHT AND MONDAY AND BRING AN INCREASE IN
WINDS AND POTENTIAL SMALL CRAFT ADVISORY CONDITIONS TO THE LOWER
LAKES.
&&
.FIRE WEATHER...
NEAR RED FLAG CONDITIONS ARE EXPECTED ON SATURDAY AFTERNOON.
A COLD FRONT WILL MOVE ACROSS THE REGION LATE SATURDAY MORNING.
BEHIND THE COLD FRONT WINDS WILL INCREASE OUT OF THE NORTHWEST WITH
SUSTAINED WINDS OF 20-25 MPH AND GUSTS OF 30-35 MPH ESPECIALLY
ACROSS THE NORTH COUNTRY AND THE HIGHER TERRAIN OF THE INTERIOR
SOUTHERN TIER AND FINGER LAKES. RH WILL ALSO DROP DURING THE
AFTERNOON FROM A COMBINATION OF DIURNAL WARMING AND DRY ADVECTION
BEHIND THE COLD FRONT. THIS WILL DROP RH TO AROUND 25 PERCENT IN
MANY AREAS AWAY FROM THE LAKESHORES DURING THE AFTERNOON.
WIND AND RH WILL APPROACH RED FLAG CRITERIA...HOWEVER THE BULK OF
THE AREA HAD A QUARTER INCH OR MORE OF RAIN LAST NIGHT. THE RECENT
RAINFALL MAKES FINE FUELS WETTER...AND TAKES OUR REGION OUT OF RED
FLAG CRITERIA. THE ONLY LOCATION WHICH RECEIVED LOWER RAIN AMOUNTS
IS THE NORTH COUNTRY...HOWEVER SNOW ACROSS THE HIGHER TERRAIN OF
THE TUG HILL AND WESTERN ADIRONDACKS HAS JUST MELTED IN THE PAST
DAY OR TWO...SO FINE FUELS ACROSS MANY OF THESE AREAS ARE LIKELY
STILL TOO WET TO JUSTIFY ANY FIRE WEATHER HEADLINES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 8 PM EDT SATURDAY FOR SLZ022-
024.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...CHURCH/HITCHCOCK
MARINE...HITCHCOCK
FIRE WEATHER...HITCHCOCK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 PM EDT THU APR 16 2015
.SYNOPSIS...CHILLY HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS AND
VIRGINIA FROM THE NORTHEAST THROUGH TONIGHT. A WEAK AREA OF LOW
PRESSURE WILL DEVELOP OFF THE SOUTHEAST U.S. COAST TODAY AND DRIFT
NORTHEAST AND AWAY FROM THE REGION ON FRIDAY. WEAK HIGH PRESSURE
WILL EXTEND INTO THE AREA LATE FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM THURSDAY...
VERY WELL DEFINED WEDGE FRONT ASSOCIATED WITH A HYBRID COLD AIR
DAMMING EVENT SHOWING UP NICELY IN OBSERVATIONS. TO THE
SOUTHEAST...A COASTAL LOW IS DEVELOPING OFF THE COAST OF SC AND
FURTHER ENHANCING THE WEDGE BOUNDARY. THIS WILL MAKE TEMPERATURE
FORECASTS VERY TRICKY TODAY AS A VERY STRONG GRADIENT WILL BE
PRESENT FROM WEST TO EAST WITH VERY COOL HIGHS IN THE WEST AND
POTENTIALLY QUITE A BIT WARMER HIGHS IN THE EAST. FOR NOW HAVE MID
50S IN THE WEST AND UPPER 60S IN THE EAST BUT BY LATE IN THE
AFTERNOON THIS COULD VERY WELL PAN OUT TO BE LOWER 50S IN THE WEST
AND LOWER TO MID 70S IN THE EASTERN TIER OF COUNTIES. PRECIPITATION
CONTINUES ACROSS THE CENTRAL PIEDMONT AND THE NORTHEASTERN COUNTIES
AIDED BY ISENTROPIC LIFT AND SOME UPPER LEVEL DIVERGENCE AS WE SIT
UNDER THE LEFT EXIT REGION OF A 250 MB JET. PRECIPITATION SHOULD
BEGIN TO TREND DOWNWARD HOWEVER AS ISENTROPIC LIFT WEAKENS AND SOME
VERY DRY MID-LEVEL AIR TO THE NORTHEAST TRIES TO WORK SOUTHWESTWARD
INTO THE CWA. THIS IS VERY EVIDENT ON THE SOUNDINGS WHERE THE KMHX
SOUNDING HAS A 5 DEGREE DEWPOINT DEPRESSION AT 850 MB AND THE KWAL
SOUNDING HAS A 33 DEGREE DEWPOINT DEPRESSION. AS PRECIPITATION MOVES
NORTHEAST...COMPOSITE RADAR SHOWS EVAPORATION OF THE
PRECIPITATION...MOST LIKELY CAUSED BY THE MID LEVEL DRY AIR. AS FAR
AS CONVECTIVE ALLOWING MODELS ARE CONCERNED...ONLY ONE REALLY HAS A
HANDLE OF THE CURRENT MODE OF PRECIP AND THAT IS THE HRRR WHICH
DEPICTS THE CURRENT PATTERN VERY WELL. GOING INTO THIS AFTERNOON THE
RAIN OVER THE CENTRAL PART OF THE CWA PUSHES NORTHEAST AND CHANCES
ELSEWHERE DIMINISH THROUGH THE AFTERNOON TO JUST A FEW PATCHES OF
DRIZZLE OR LIGHT RAIN BY THIS EVENING. CLOUDS SHOULD REMAIN
OVERNIGHT...THUS MODERATING LOWS...MAINLY LOW TO MIDDLE 50S NW TO SE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 245 PM THURSDAY...
FRIDAY SHOULD SEE THE BEGINNING OF A SLOW IMPROVEMENT IN SKY
CONDITION AND TEMPS. DEVELOPING (THOUGH WEAK) NW FLOW IN THE MID-
UPPER LEVELS WILL BEGIN TO SCOUR THE CAD AIR MASS FROM ALOFT.
STILL...RESIDUAL LOW LEVEL MOISTURE WILL REMAIN HIGH ENOUGH TO
PRODUCE EXTENSIVE CLOUDINESS IN THE MORNING WITH SOME PARTIAL BREAKS
DEVELOPING IN THE AFTERNOON. THIS HEATING ALONG WITH THE PASSAGE OF
A WEAK MID LEVEL TROUGH MAY PROVIDE ENOUGH LIFT TO GENERATE AN
ISOLATED SHOWER OR THUNDERSTORM ACROSS CENTRAL NC. TEMPS WILL BEGIN
TO RECOVER FRIDAY THOUGH IF CLOUDS STICK AROUND A LOT LONGER THAN
EXPECTED...MAX TEMPS MAY END UP BEING 3-5 DEGREES COOLER THAN
CURRENTLY FORECAST...ESPECIALLY ACROSS THE NORTHERN PIEDMONT. MAX
TEMPS FRIDAY LOW-MID 70S. FRIDAY NIGHT... PARTIAL CLEARING MAY LEAD
TO THE DEVELOPMENT OF FOGGY CONDITIONS AFTER MIDNIGHT. MIN TEMPS 55-
60. -WSS
SAT/SAT NIGHT: EXPECT DRY WEATHER AND PLENTY OF SUNSHINE SAT. A WEAK
BACKDOOR FRONT WILL DROP THROUGH NC IN THE MORNING... OTHERWISE
WE`LL HAVE SURFACE HIGH PRESSURE OVER THE REGION AND A DRY/SUBSIDING
COLUMN BENEATH MID LEVEL RIDGING. WE MAY GET WARM AND MOIST ENOUGH
IN THE SOUTHEAST FOR POTENTIAL INLAND-MOVING SEA BREEZE
CONVECTION... SO WILL RETAIN THE EXISTING ISOLATED MENTION FOR THE
AFTERNOON. WITH THICKNESSES LIKELY NEARING 20 M ABOVE NORMAL AND
GOOD MIXING EXPECTED... HIGHS IN THE UPPER 70S TO LOWER 80S APPEAR
ATTAINABLE. A STRONG VORTICITY MAX AND WAVE CROSSING NRN NEW ENGLAND
SAT WILL HELP PROPEL A MORE PRONOUNCED BACKDOOR FRONT SOUTHWARD TO
NEAR THE VA/NC BORDER LATE SAT NIGHT... PUSHED BY COOL DENSE HIGH
PRESSURE CENTERED OVER WRN QUEBEC. MODELS DIFFER REGARDING HOW FAR
(IF AT ALL) THE FRONT GETS INTO NE NC... WITH THE GFS A BIT FARTHER
SSW THAN THE NAM/ECMWF. GIVEN THE STRENGTH OF THE PARENT HIGH AND
INTENSITY OF THE NEW ENGLAND WAVE... THINK WE`LL SEE ENOUGH
PENETRATION INTO OUR CWA FOR BRIEFLY LOWER DEWPOINTS AND TEMPS INTO
THE NE CWA. EXPECT LOWS IN THE UPPER 50S TO LOWER 60S EXCEPT MID 50S
FAR NE. THE STRONG LOW CLOSING OFF OVER SASK/MANITOBA AND ATTENDING
TROUGH THROUGH THE DAKOTAS ULTIMATELY PICK UP THE SRN STREAM LOW
OVER THE CENTRAL PLAINS... CULMINATING IN DEEP MID LEVEL TROUGHING
THROUGH CENTRAL NOAM BY DAWN SUNDAY. WHILE WE`RE LIKELY TO SEE
INCREASING CLOUDS FROM THE SW SAT NIGHT WITH ENCROACHING DPVA ALOFT
AND IMPROVING MOIST INFLOW IN THE LOWER LEVELS... ANY LIFT IS TOO
WEAK AND THE COLUMN STILL TOO DRY OVERALL TO SUPPORT ANY PRECIP
THROUGH DAWN SUNDAY. -GIH
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 245 PM THURSDAY...
SUN-MON NIGHT: A WET AND POTENTIALLY STORMY PERIOD. MID LEVEL FLOW
OVER OUR REGION BECOMES INCREASINGLY CYCLONIC AS THE SLIGHTLY
POSITIVELY TILTED BUT SLOWLY DAMPENING LARGE SCALE TROUGH APPROACHES
FROM THE WSW. AT THE SURFACE... THE ASSOCIATED FRONTAL SYSTEM WILL
OCCLUDE OVER THE UPPER MIDWEST AND GREAT LAKES SUN/SUN NIGHT... WITH
THE BACKDOOR FRONT AROUND THE NC/VA BORDER SLOWLY RETREATING BACK TO
THE NNE AS A WARM FRONT... WHILE THE PRIMARY COLD FRONT EXTENDS FROM
A TRIPLE POINT LOW OVER LOWER MICH DOWN THROUGH THE MID/LOWER MISS
VALLEY. MECHANISMS TO FORCE ASCENT SUCH AS MID LEVEL DPVA... UPPER
DIVERGENCE... AND LOWER LEVEL (850-925 MB) MASS CONVERGENCE WILL BE
STRENGTHENING (ESPECIALLY OVER WRN NC/SW VA) LATE SUN... PERSISTING
THROUGH SUN EVENING AND INTO THE NIGHT... AND MOISTURE WILL BE
ABUNDANT WITH AN INFLUX OF PW VALUES OVER 1.5"... OR WELL OVER 200%
OF NORMAL. GIVEN THIS PLENTIFUL WATER CONTENT AND GOOD LIFT...
TRAINING BANDS OF MODERATE RAIN COULD BRING LOCALIZED FLOODING
PROBLEMS. MODELS CONTINUE TO SLOW DOWN THE ARRIVAL OF THE MID LEVEL
TROUGH AND ITS ACCOMPANYING PRECIP... 6-9 HRS SLOWER THAN YESTERDAY
MORNING`S RUNS... AND WILL CONTINUE TO REFLECT THIS IN THE FORECAST.
WILL RAMP UP POPS TO LIKELY WEST/SMALL CHANCE EAST SUN MORNING...
THEN GO TO CATEGORICAL WEST/GOOD CHANCE EAST SUN AFTERNOON... BEFORE
GOING CATEGORICAL AREAWIDE SUN EVENING/NIGHT. WHILE THE LARGE SCALE
MODELS DON`T DEPICT MUCH INSTABILITY AT ALL SUNDAY WITH PRIMARILY
MOIST ADIABATIC FORECAST PROFILES... I DO HAVE SOME CONCERN ABOUT
POCKETS OF CONVECTION AND AN ISOLATED THREAT OF A QUICK WEAK SPIN-UP
IN OUR FAR NORTHWEST LATE SUNDAY INTO SUNDAY NIGHT... ESPECIALLY
NEAR A WEAK ALONG-FRONT LOW THAT THE GFS/ECMWF DEVELOP OVER SOUTH
CENTRAL VA. UPPER DIVERGENCE REACHES A HEFTY MAXIMUM OVER THE SRN
APPALACHIANS SUN EVENING... WITH A 40-50 KT 850 MB JETLET FROM THE
SSE... AND THE RETREATING BACKDOOR FRONTAL ZONE AND AFOREMENTIONED
LOW COULD PROVIDE A SOURCE FOR ENHANCED LOW LEVEL VORTICITY WITH
FORECAST SOUNDINGS SHOWING A STRONGLY CURVED HODOGRAPH. WILL
CONTINUE TO MONITOR. TOTAL RAINFALL IS LIKELY TO REACH AT LEAST ONE
INCH IN MOST SPOTS THROUGH SUN NIGHT... AND WITH A DEEP WARM LAYER
(LCL TO 0C) NEAR 3.5 KM FAVORING WARM RAIN PROCESSES... LOCALLY
HIGHER TOTALS ARE POSSIBLE. WILL TAPER POPS DOWN MON MORNING WEST TO
EAST AS THE MID LEVEL TROUGH AXIS AND CONVEYOR BELT OF PEAK MOISTURE
PUSHES TO OUR NORTHEAST... PLACING US FULLY IN THE WARM SECTOR WITH
A PUNCH OF MID LEVEL DRY AIR ARRIVING FROM THE SW. ANY HEATING AT
ALL WILL PUSH UP MUCAPE TO 1500-2000 J/KG (AS THE GFS SUGGESTS) MON
AFTERNOON WITH 25-30 KT WSW 850 MB WINDS AND BULK SHEAR NEAR 30-35
KTS. THE SLOWLY LOWERING DYNAMIC FORCING FOR ASCENT MAY LIMIT THE
THREAT OF SEVERE STORMS... BUT STILL EXPECT AT LEAST A FEW STRONG
CELLS... ESPECIALLY IF WE DO INDEED GET SOME HEATING AHEAD OF THE
COLD FRONT. AFTER A DOWNWARD TREND TO RAIN WEST TO EAST IN THE
MORNING... WILL REBOUND WITH SCATTERED SHOWERS AND STORMS MON
AFTERNOON INTO EARLY EVENING. A FEW OF THESE COULD PRODUCE STRONG
GUSTY STRAIGHT LINE WINDS GIVEN INDICATIONS OF A STRAIGHT LINE
HODOGRAPH. HIGHS FROM AROUND 70 NW TO THE MID 70S SE. LOWS AROUND 60
TO THE MID 60S WITH THE FRONT LIKELY NOT COMING THROUGH UNTIL LATE.
TUE-THU: FAIRLY QUIET AND DRY WITH SURFACE HIGH PRESSURE BUILDING IN
FROM THE WEST. LARGE/DEEP MID LEVEL LOW PRESSURE CENTERED OVER AND
NORTH OF THE NRN GREAT LAKES WILL COVER MUCH OF CENTRAL AND EASTERN
NOAM... BRINGING SEASONABLY COOL TEMPS AS IT SITS AND SPINS THROUGH
MID WEEK. WE COULD SEE A QUICK SHOT OF LIGHT PRECIP WITH A FRONT
APPROACHING FROM THE NW WED NIGHT OR THU... HOWEVER OUR MOISTURE
SOURCES WILL REMAIN UNTAPPED AND LIFT APPEARS WEAK... SO THIS SHOULD
AMOUNT TO ONLY LIGHT PRECIP AT MOST... AND WILL KEEP POPS WED
NIGHT/THU BELOW CLIMATOLOGY. TEMPS SHOULD HOLD NEAR OR JUST BELOW
NORMAL THROUGH THE PERIOD. -GIH
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 205 PM THURSDAY...
24 HOUR TAF PERIOD: VARIABLE CONDITIONS ACROSS THE CWA RIGHT NOW AS
PREDOMINANTLY IFR CEILINGS AND MVFR VISIBILITIES HAVE OVERSPREAD THE
SOUTHWESTERN COUNTIES...MVFR CONDITIONS OVER THE NW PIEDMONT ARE
SETTLING BACK IN AND VFR TO THE EAST. WHILE CONDITIONS WILL VARY
THIS AFTERNOON BASED ON CLOUD COVER AND PLACEMENT OF PRECIPITATION
THERE WILL BE AN OVERALL TREND OF IMPROVING IN THE EAST THIS
AFTERNOON AND HOLDING STEADY IN THE WEST WHERE THE CAD WEDGE HAS
MORE INFLUENCE. OVERNIGHT TONIGHT EXPECT CEILINGS TO GO DOWN TO AT
LEAST IFR LEVELS IN MOST LOCATIONS. THIS WILL HAPPEN EARLIER IN THE
WEST AND LATER IN EAST. CONVERSELY...AFTER SUNRISE FRIDAY EXPECT
EASTERN SITES TO RECOVER TO VFR FASTER THAN WESTERN SITES WHICH
COULD HOLD MVFR THROUGH THE END OF THE TAF PERIOD. MOSTLY NNE WINDS
AT THIS TIME AT 5-10 KTS BUT AS COASTAL LOW DEVELOPS OFF OF
NC...BIGGER EASTWARD COMPONENT COMING IN...CURRENTLY NOTED AT KRWI.
BIGGEST THREAT TO CEILINGS OVERNIGHT WILL BE LOW CEILINGS WITH
VISIBILITIES SECONDARY. RAIN SHOULD TAPER OFF AFTER SUNSET. ONCE
THAT HAPPENS SHOULD BE DRY THROUGH THE END OF THE TAF PERIOD.
LONG TERM: RETURN TO MAINLY VFR CONDITIONS FRIDAY AFTERNOON THROUGH
SATURDAY. CHANCE FOR ADVERSE CONDITIONS WITH A COLD FRONT SUNDAY
INTO MONDAY AND THEN IMPROVING CONDITIONS FOR MIDWEEK NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...ELLIS
SHORT TERM...WSS/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
207 PM EDT THU APR 16 2015
.SYNOPSIS...CHILLY HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS AND
VIRGINIA FROM THE NORTHEAST THROUGH TONIGHT. A WEAK AREA OF LOW
PRESSURE WILL DEVELOP OFF THE SOUTHEAST U.S. COAST TODAY AND DRIFT
NORTHEAST AND AWAY FROM THE REGION ON FRIDAY. WEAK HIGH PRESSURE
WILL EXTEND INTO THE AREA LATE FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM THURSDAY...
VERY WELL DEFINED WEDGE FRONT ASSOCIATED WITH A HYBRID COLD AIR
DAMMING EVENT SHOWING UP NICELY IN OBSERVATIONS. TO THE
SOUTHEAST...A COASTAL LOW IS DEVELOPING OFF THE COAST OF SC AND
FURTHER ENHANCING THE WEDGE BOUNDARY. THIS WILL MAKE TEMPERATURE
FORECASTS VERY TRICKY TODAY AS A VERY STRONG GRADIENT WILL BE
PRESENT FROM WEST TO EAST WITH VERY COOL HIGHS IN THE WEST AND
POTENTIALLY QUITE A BIT WARMER HIGHS IN THE EAST. FOR NOW HAVE MID
50S IN THE WEST AND UPPER 60S IN THE EAST BUT BY LATE IN THE
AFTERNOON THIS COULD VERY WELL PAN OUT TO BE LOWER 50S IN THE WEST
AND LOWER TO MID 70S IN THE EASTERN TIER OF COUNTIES. PRECIPITATION
CONTINUES ACROSS THE CENTRAL PIEDMONT AND THE NORTHEASTERN COUNTIES
AIDED BY ISENTROPIC LIFT AND SOME UPPER LEVEL DIVERGENCE AS WE SIT
UNDER THE LEFT EXIT REGION OF A 250 MB JET. PRECIPITATION SHOULD
BEGIN TO TREND DOWNWARD HOWEVER AS ISENTROPIC LIFT WEAKENS AND SOME
VERY DRY MID-LEVEL AIR TO THE NORTHEAST TRIES TO WORK SOUTHWESTWARD
INTO THE CWA. THIS IS VERY EVIDENT ON THE SOUNDINGS WHERE THE KMHX
SOUNDING HAS A 5 DEGREE DEWPOINT DEPRESSION AT 850 MB AND THE KWAL
SOUNDING HAS A 33 DEGREE DEWPOINT DEPRESSION. AS PRECIPITATION MOVES
NORTHEAST...COMPOSITE RADAR SHOWS EVAPORATION OF THE
PRECIPITATION...MOST LIKELY CAUSED BY THE MID LEVEL DRY AIR. AS FAR
AS CONVECTIVE ALLOWING MODELS ARE CONCERNED...ONLY ONE REALLY HAS A
HANDLE OF THE CURRENT MODE OF PRECIP AND THAT IS THE HRRR WHICH
DEPICTS THE CURRENT PATTERN VERY WELL. GOING INTO THIS AFTERNOON THE
RAIN OVER THE CENTRAL PART OF THE CWA PUSHES NORTHEAST AND CHANCES
ELSEWHERE DIMINISH THROUGH THE AFTERNOON TO JUST A FEW PATCHES OF
DRIZZLE OR LIGHT RAIN BY THIS EVENING. CLOUDS SHOULD REMAIN
OVERNIGHT...THUS MODERATING LOWS...MAINLY LOW TO MIDDLE 50S NW TO SE.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 317 AM THURSDAY...
FRIDAY SHOULD SEE THE BEGINNING OF A SLOW IMPROVEMENT IN SKY
CONDITION AND TEMPS. DEVELOPING (THOUGH WEAK) NW FLOW IN THE MID-
UPPER LEVELS WILL BEGIN TO SCOUR THE CAD AIR MASS FROM ALOFT.
STILL...RESIDUAL LOW LEVEL MOISTURE WILL REMAIN HIGH ENOUGH TO
PRODUCE EXTENSIVE CLOUDINESS IN THE MORNING WITH SOME PARTIAL BREAKS
DEVELOPING IN THE AFTERNOON. THIS HEATING ALONG WITH THE PASSAGE OF
A WEAK MID LEVEL TROUGH MAY PROVIDE ENOUGH LIFT TO GENERATE AN
ISOLATED SHOWER OR THUNDERSTORM ACROSS CENTRAL NC. TEMPS WILL BEGIN
TO RECOVER FRIDAY THOUGH IF CLOUDS STICK AROUND A LOT LONGER THAN
EXPECTED...MAX TEMPS MAY END UP BEING 3-5 DEGREES COOLER THAN
CURRENTLY FORECAST...ESPECIALLY ACROSS THE NORTHERN PIEDMONT. MAX
TEMPS FRIDAY LOW-MID 70S.
FRIDAY NIGHT..PARTIAL CLEARING MAY LEAD TO THE DEVELOPMENT OF FOGGY
CONDITIONS AFTER MIDNIGHT. MIN TEMPS 55-60.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 320 AM THURSDAY...
SATURDAY AND SATURDAY NIGHT: MID LEVEL S/W RIDGING WILL LARGELY KEEP
CENTRAL NC DRY ON SATURDAY AND SATURDAY NIGHT. HOWEVER... WITH AND
EASTERLY TO SOUTHEASTERLY SURFACE FLOW DEVELOPING LATE SATURDAY
ALONG WITH DAYTIME HEATING CANT COMPLETELY RULE OUT SOME AFTERNOON
SHOWERS AND STORMS ACROSS FAR EASTERN PORTIONS OF THE AREA WHERE LOW
LEVEL CONVERGENCE MAY BE ENHANCED SOME ALONG PERHAPS A SEABREEZE.
THUS... WILL GO WITH A SLIGHT CHANCE FOR SHOWERS AND STORMS ACROSS
OUR FAR EASTERN COUNTIES FOR SATURDAY AFTERNOON. WITH SKIES NOW
EXPECTED TO BE AT LEAST PARTLY SUNNY AT TIMES WILL RAISE HIGH TEMPS
A DEGREE OR TWO INTO THE UPPER 70S NW TO LOWER 80S SE.
THE LATEST GFS/ECMWF/NAM NOW SHOW THE ONSET OF PRECIP DELAYED A GOOD
6 TO 12 HOURS FROM PREVIOUS FORECASTS. THUS... WILL NOT INTRODUCE
POPS UNTIL CLOSE TO DAYBREAK... FIRST IN THE WEST THEN SPREADING
EAST THROUGH THE DAY ON SUNDAY. WITH INCREASING SOUTHERLY LOW LEVEL
FLOW AND CLOUD COVER ON SATURDAY NIGHT/EARLY SUNDAY MORNING EXPECT
LOW TEMPS WILL ABOVE NORMAL... GENERALLY RANGING FROM THE MID 50S IN
THE FAR NE (WHERE WE MAY SEE SOME CLEARING BRIEFLY WITH THE LOSS OF
HEATING AND PRIOR TO THE INCREASING OF MID AND HIGH LEVEL CLOUDS
COVER) TO GENERALLY NEAR 60 ELSEWHERE.
SUNDAY THROUGH MONDAY NIGHT: GOOD MOISTURE TRANSPORT IS EXPECTED ON
SUNDAY INTO SUNDAY NIGHT AS CLOSED LOW INVOF THE FOUR CORNERS REGION
(CURRENTLY) SHIFT EASTWARD AND OPENS WHILE COMBINING WITH A NORTHERN
STREAM TROUGH TO AMPLIFY THE MID/UPPER LEVEL FLOW ACROSS THE CENTRAL
AND EASTERN PART OF THE COUNTRY LATE WEEKEND INTO EARLY NEXT WEEK.
THIS WILL HELP TO DRIVE A LEAD DEEP MOIST AXIS THROUGH CENTRAL NC
LATE SUNDAY THROUGH EARLY MONDAY MORNING. WITH STRONG SOUTHERLY LOW
LEVEL FLOW WITH THIS SYSTEM AND EXCELLENT MOISTURE TRANSPORT WE
SHOULD SEE A LARGE BAND OF SHOWER/ISOLATED STORMS AND HEAVY RAIN
MOVE THROUGH CENTRAL NC LATE SUNDAY INTO SUNDAY NIGHT... WITH A MAIN
THREAT OF HEAVY RAIN. ALTHOUGH GIVEN THE STRONG LOW LEVEL WIND
FIELDS CAN COMPLETELY RULE OUT AT LEAST A STRONG WIND GUST OR TWO.
BUT GIVEN THE RATHER WEAK INSTABILITY AND POOR DIURNAL TIMING FOR
THE MOST PART ANY SEVERE THREAT SHOULD REMAIN LOW. HIGHS SHOULD BE
COOLER SUNDAY WITH THE INCREASE IN CLOUDS AND EVENTUALLY PRECIP LATE
IN THE DAY...EXPECT HIGHS TO BE IN THE MID TO UPPER 60S NW (WHERE WE
COULD SEE A BRIEF CAD AIRMASS DEVELOP) TO THE MID 70S SE/E (MAYBE
EVEN A FEW UPPER 70S SE). LOWS MONDAY MORNING SHOULD BE WARM FOR
THIS TIME OF YEAR... EXPECT LOWS IN THE LOWER TO MID 60S.
THE MAIN SURFACE COLD FRONT SHOULD MOVE THROUGH THE REGION LATE
MONDAY INTO MONDAY EVENING. WHILE THE STRONGER MID AND LOW LEVEL
FLOW WILL HAVE PUSHED TO THE EAST... WE SHOULD SEE INSTABILITY
INCREASE AS SOME DRIER MID LEVEL AIR WORKS INTO THE AREA FROM THE
SOUTHWEST ON MONDAY MORNING/AFTERNOON. THIS SHOULD HELP TO YIELD AT
LEAST SOME DESTABILIZATION AHEAD OF THE FRONT ON MONDAY RESULTING IN
ISOLATED TO SCATTERED SHOWER AND STORMS MONDAY AFTERNOON/EVENING IN
ADVANCE OF THE FRONT... WITH POSSIBLY A FEW STRONG TO MAYBE SEVERE
STORMS (AS DEEP LAYER SHEAR WILL STILL BE AROUND 25 TO 35 KTS). BEST
CHANCE OF ANY SVR AT THIS TIME (KEEP IN MIND WE ARE STILL A WAYS OUT
IN TIME) WOULD BE ACROSS EASTERN PORTIONS OF THE AREA. HIGHS MONDAY
ARE EXPECTED TO BE IN THE 70S TO LOWER 80S EAST/SOUTHEAST. LOWS
TUESDAY MORNING RANGING FROM THE MID 50S NW TO AROUND 60 SE.
TUESDAY THROUGH WEDNESDAY: DRIER WEATHER IS EXPECTED BEHIND THE
FRONT ON TUESDAY AND WEDNESDAY... WITH A MUCH DRIER AIRMASS
ADVECTING INTO THE REGION. HIGH TEMPS SHOULD BE NEAR NORMAL GENERALLY
IN THE 70S... WITH LOWS IN THE 40S AND 50S.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 205 PM THURSDAY...
24 HOUR TAF PERIOD: VARIABLE CONDITIONS ACROSS THE CWA RIGHT NOW AS
PREDOMINANTLY IFR CEILINGS AND MVFR VISIBILITIES HAVE OVERSPREAD THE
SOUTHWESTERN COUNTIES...MVFR CONDITIONS OVER THE NW PIEDMONT ARE
SETTLING BACK IN AND VFR TO THE EAST. WHILE CONDITIONS WILL VARY
THIS AFTERNOON BASED ON CLOUD COVER AND PLACEMENT OF PRECIPITATION
THERE WILL BE AN OVERALL TREND OF IMPROVING IN THE EAST THIS
AFTERNOON AND HOLDING STEADY IN THE WEST WHERE THE CAD WEDGE HAS
MORE INFLUENCE. OVERNIGHT TONIGHT EXPECT CEILINGS TO GO DOWN TO AT
LEAST IFR LEVELS IN MOST LOCATIONS. THIS WILL HAPPEN EARLIER IN THE
WEST AND LATER IN EAST. CONVERSELY...AFTER SUNRISE FRIDAY EXPECT
EASTERN SITES TO RECOVER TO VFR FASTER THAN WESTERN SITES WHICH
COULD HOLD MVFR THROUGH THE END OF THE TAF PERIOD. MOSTLY NNE WINDS
AT THIS TIME AT 5-10 KTS BUT AS COASTAL LOW DEVELOPS OFF OF
NC...BIGGER EASTWARD COMPONENT COMING IN...CURRENTLY NOTED AT KRWI.
BIGGEST THREAT TO CEILINGS OVERNIGHT WILL BE LOW CEILINGS WITH
VISIBILITIES SECONDARY. RAIN SHOULD TAPER OFF AFTER SUNSET. ONCE
THAT HAPPENS SHOULD BE DRY THROUGH THE END OF THE TAF PERIOD.
LONG TERM: RETURN TO MAINLY VFR CONDITIONS FRIDAY AFTERNOON THROUGH
SATURDAY. CHANCE FOR ADVERSE CONDITIONS WITH A COLD FRONT SUNDAY
INTO MONDAY AND THEN IMPROVING CONDITIONS FOR MIDWEEK NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...ELLIS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1104 AM EDT THU APR 16 2015
.SYNOPSIS...CHILLY HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS AND
VIRGINIA FROM THE NORTHEAST THROUGH TONIGHT. A WEAK AREA OF LOW
PRESSURE WILL DEVELOP OFF THE SOUTHEAST U.S. COAST TODAY AND DRIFT
NORTHEAST AND AWAY FROM THE REGION ON FRIDAY. WEAK HIGH PRESSURE
WILL EXTEND INTO THE AREA LATE FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM THURSDAY...
VERY WELL DEFINED WEDGE FRONT ASSOCIATED WITH A HYBRID COLD AIR
DAMMING EVENT SHOWING UP NICELY IN OBSERVATIONS. TO THE
SOUTHEAST...A COASTAL LOW IS DEVELOPING OFF THE COAST OF SC AND
FURTHER ENHANCING THE WEDGE BOUNDARY. THIS WILL MAKE TEMPERATURE
FORECASTS VERY TRICKY TODAY AS A VERY STRONG GRADIENT WILL BE
PRESENT FROM WEST TO EAST WITH VERY COOL HIGHS IN THE WEST AND
POTENTIALLY QUITE A BIT WARMER HIGHS IN THE EAST. FOR NOW HAVE MID
50S IN THE WEST AND UPPER 60S IN THE EAST BUT BY LATE IN THE
AFTERNOON THIS COULD VERY WELL PAN OUT TO BE LOWER 50S IN THE WEST
AND LOWER TO MID 70S IN THE EASTERN TIER OF COUNTIES. PRECIPITATION
CONTINUES ACROSS THE CENTRAL PIEDMONT AND THE NORTHEASTERN COUNTIES
AIDED BY ISENTROPIC LIFT AND SOME UPPER LEVEL DIVERGENCE AS WE SIT
UNDER THE LEFT EXIT REGION OF A 250 MB JET. PRECIPITATION SHOULD
BEGIN TO TREND DOWNWARD HOWEVER AS ISENTROPIC LIFT WEAKENS AND SOME
VERY DRY MID-LEVEL AIR TO THE NORTHEAST TRIES TO WORK SOUTHWESTWARD
INTO THE CWA. THIS IS VERY EVIDENT ON THE SOUNDINGS WHERE THE KMHX
SOUNDING HAS A 5 DEGREE DEWPOINT DEPRESSION AT 850 MB AND THE KWAL
SOUNDING HAS A 33 DEGREE DEWPOINT DEPRESSION. AS PRECIPITATION MOVES
NORTHEAST...COMPOSITE RADAR SHOWS EVAPORATION OF THE
PRECIPITATION...MOST LIKELY CAUSED BY THE MID LEVEL DRY AIR. AS FAR
AS CONVECTIVE ALLOWING MODELS ARE CONCERNED...ONLY ONE REALLY HAS A
HANDLE OF THE CURRENT MODE OF PRECIP AND THAT IS THE HRRR WHICH
DEPICTS THE CURRENT PATTERN VERY WELL. GOING INTO THIS AFTERNOON THE
RAIN OVER THE CENTRAL PART OF THE CWA PUSHES NORTHEAST AND CHANCES
ELSEWHERE DIMINISH THROUGH THE AFTERNOON TO JUST A FEW PATCHES OF
DRIZZLE OR LIGHT RAIN BY THIS EVENING. CLOUDS SHOULD REMAIN
OVERNIGHT...THUS MODERATING LOWS...MAINLY LOW TO MIDDLE 50S NW TO SE.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 317 AM THURSDAY...
FRIDAY SHOULD SEE THE BEGINNING OF A SLOW IMPROVEMENT IN SKY
CONDITION AND TEMPS. DEVELOPING (THOUGH WEAK) NW FLOW IN THE MID-
UPPER LEVELS WILL BEGIN TO SCOUR THE CAD AIR MASS FROM ALOFT.
STILL...RESIDUAL LOW LEVEL MOISTURE WILL REMAIN HIGH ENOUGH TO
PRODUCE EXTENSIVE CLOUDINESS IN THE MORNING WITH SOME PARTIAL BREAKS
DEVELOPING IN THE AFTERNOON. THIS HEATING ALONG WITH THE PASSAGE OF
A WEAK MID LEVEL TROUGH MAY PROVIDE ENOUGH LIFT TO GENERATE AN
ISOLATED SHOWER OR THUNDERSTORM ACROSS CENTRAL NC. TEMPS WILL BEGIN
TO RECOVER FRIDAY THOUGH IF CLOUDS STICK AROUND A LOT LONGER THAN
EXPECTED...MAX TEMPS MAY END UP BEING 3-5 DEGREES COOLER THAN
CURRENTLY FORECAST...ESPECIALLY ACROSS THE NORTHERN PIEDMONT. MAX
TEMPS FRIDAY LOW-MID 70S.
FRIDAY NIGHT..PARTIAL CLEARING MAY LEAD TO THE DEVELOPMENT OF FOGGY
CONDITIONS AFTER MIDNIGHT. MIN TEMPS 55-60.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 320 AM THURSDAY...
SATURDAY AND SATURDAY NIGHT: MID LEVEL S/W RIDGING WILL LARGELY KEEP
CENTRAL NC DRY ON SATURDAY AND SATURDAY NIGHT. HOWEVER... WITH AND
EASTERLY TO SOUTHEASTERLY SURFACE FLOW DEVELOPING LATE SATURDAY
ALONG WITH DAYTIME HEATING CANT COMPLETELY RULE OUT SOME AFTERNOON
SHOWERS AND STORMS ACROSS FAR EASTERN PORTIONS OF THE AREA WHERE LOW
LEVEL CONVERGENCE MAY BE ENHANCED SOME ALONG PERHAPS A SEABREEZE.
THUS... WILL GO WITH A SLIGHT CHANCE FOR SHOWERS AND STORMS ACROSS
OUR FAR EASTERN COUNTIES FOR SATURDAY AFTERNOON. WITH SKIES NOW
EXPECTED TO BE AT LEAST PARTLY SUNNY AT TIMES WILL RAISE HIGH TEMPS
A DEGREE OR TWO INTO THE UPPER 70S NW TO LOWER 80S SE.
THE LATEST GFS/ECMWF/NAM NOW SHOW THE ONSET OF PRECIP DELAYED A GOOD
6 TO 12 HOURS FROM PREVIOUS FORECASTS. THUS... WILL NOT INTRODUCE
POPS UNTIL CLOSE TO DAYBREAK... FIRST IN THE WEST THEN SPREADING
EAST THROUGH THE DAY ON SUNDAY. WITH INCREASING SOUTHERLY LOW LEVEL
FLOW AND CLOUD COVER ON SATURDAY NIGHT/EARLY SUNDAY MORNING EXPECT
LOW TEMPS WILL ABOVE NORMAL... GENERALLY RANGING FROM THE MID 50S IN
THE FAR NE (WHERE WE MAY SEE SOME CLEARING BRIEFLY WITH THE LOSS OF
HEATING AND PRIOR TO THE INCREASING OF MID AND HIGH LEVEL CLOUDS
COVER) TO GENERALLY NEAR 60 ELSEWHERE.
SUNDAY THROUGH MONDAY NIGHT: GOOD MOISTURE TRANSPORT IS EXPECTED ON
SUNDAY INTO SUNDAY NIGHT AS CLOSED LOW INVOF THE FOUR CORNERS REGION
(CURRENTLY) SHIFT EASTWARD AND OPENS WHILE COMBINING WITH A NORTHERN
STREAM TROUGH TO AMPLIFY THE MID/UPPER LEVEL FLOW ACROSS THE CENTRAL
AND EASTERN PART OF THE COUNTRY LATE WEEKEND INTO EARLY NEXT WEEK.
THIS WILL HELP TO DRIVE A LEAD DEEP MOIST AXIS THROUGH CENTRAL NC
LATE SUNDAY THROUGH EARLY MONDAY MORNING. WITH STRONG SOUTHERLY LOW
LEVEL FLOW WITH THIS SYSTEM AND EXCELLENT MOISTURE TRANSPORT WE
SHOULD SEE A LARGE BAND OF SHOWER/ISOLATED STORMS AND HEAVY RAIN
MOVE THROUGH CENTRAL NC LATE SUNDAY INTO SUNDAY NIGHT... WITH A MAIN
THREAT OF HEAVY RAIN. ALTHOUGH GIVEN THE STRONG LOW LEVEL WIND
FIELDS CAN COMPLETELY RULE OUT AT LEAST A STRONG WIND GUST OR TWO.
BUT GIVEN THE RATHER WEAK INSTABILITY AND POOR DIURNAL TIMING FOR
THE MOST PART ANY SEVERE THREAT SHOULD REMAIN LOW. HIGHS SHOULD BE
COOLER SUNDAY WITH THE INCREASE IN CLOUDS AND EVENTUALLY PRECIP LATE
IN THE DAY...EXPECT HIGHS TO BE IN THE MID TO UPPER 60S NW (WHERE WE
COULD SEE A BRIEF CAD AIRMASS DEVELOP) TO THE MID 70S SE/E (MAYBE
EVEN A FEW UPPER 70S SE). LOWS MONDAY MORNING SHOULD BE WARM FOR
THIS TIME OF YEAR... EXPECT LOWS IN THE LOWER TO MID 60S.
THE MAIN SURFACE COLD FRONT SHOULD MOVE THROUGH THE REGION LATE
MONDAY INTO MONDAY EVENING. WHILE THE STRONGER MID AND LOW LEVEL
FLOW WILL HAVE PUSHED TO THE EAST... WE SHOULD SEE INSTABILITY
INCREASE AS SOME DRIER MID LEVEL AIR WORKS INTO THE AREA FROM THE
SOUTHWEST ON MONDAY MORNING/AFTERNOON. THIS SHOULD HELP TO YIELD AT
LEAST SOME DESTABILIZATION AHEAD OF THE FRONT ON MONDAY RESULTING IN
ISOLATED TO SCATTERED SHOWER AND STORMS MONDAY AFTERNOON/EVENING IN
ADVANCE OF THE FRONT... WITH POSSIBLY A FEW STRONG TO MAYBE SEVERE
STORMS (AS DEEP LAYER SHEAR WILL STILL BE AROUND 25 TO 35 KTS). BEST
CHANCE OF ANY SVR AT THIS TIME (KEEP IN MIND WE ARE STILL A WAYS OUT
IN TIME) WOULD BE ACROSS EASTERN PORTIONS OF THE AREA. HIGHS MONDAY
ARE EXPECTED TO BE IN THE 70S TO LOWER 80S EAST/SOUTHEAST. LOWS
TUESDAY MORNING RANGING FROM THE MID 50S NW TO AROUND 60 SE.
TUESDAY THROUGH WEDNESDAY: DRIER WEATHER IS EXPECTED BEHIND THE
FRONT ON TUESDAY AND WEDNESDAY... WITH A MUCH DRIER AIRMASS
ADVECTING INTO THE REGION. HIGH TEMPS SHOULD BE NEAR NORMAL GENERALLY
IN THE 70S... WITH LOWS IN THE 40S AND 50S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 747 AM THURSDAY...
AN UNSETTLED WEATHER PATTERN WILL CONTINUE ACROSS CENTRAL NC THROUGH
THE REMAINDER OF THE WORK WEEK. A BRIEF RESPITE FROM THE SUB VFR
CONDITIONS EXPECTED SATURDAY BEFORE A LOW PRESSURE SYSTEM AFFECTS
OUR REGION SUNDAY.
SFC HIGH PRESSURE WILL CONTINUE TO EXTEND ACROSS CENTRAL NC TODAY
THROUGH EARLY FRIDAY...KEEPING A COOL MOIST STABLE AIR MASS IN
PLACE. UPPER LEVEL DISTURBANCES TRAVERSING OVERHEAD WILL CAUSE
PERIODS OF PATCHY LIGH RAIN THROUGH THIS AFTERNOON.
THE FLOW ALOFT WILL BECOME MORE WESTERLY AND EVENTUALLY NWLY BY LATE
FRIDAY. MEANWHILE THE SFC RIDGE WILL WEAKEN. THIS WILL LEAD TO A
SLOW IMPROVEMENT IN AVIATION CONDITIONS THROUGH FRIDAY NIGHT. EXPECT
LOW END VFR/MVFR CEILINGS TO PERSIST THROUGH EARLY FRIDAY. PATCHES
OF LIGHT RAIN WILL OCCUR THROUGH EARLY AFTERNOON THEN DIMINISH.
AFTER SUNSET...CEILINGS WILL BECOME IFR OVER MOST OF THE AREA AND
REMAIN IFR UNTIL MID MORNING FRIDAY. MOST LOCATIONS SHOULD SEE VFR
CONDITIONS FRIDAY AFTERNOON...PERSISTING THROUGH SATURDAY.
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST LATE SATURDAY AND
AFFECT OUR REGION SUNDAY THROUGH EARLY MONDAY. THIS SYSTEM WILL
BRING A HIGH PROBABILITY OF SHOWERS AND SUB VFR CEILINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...ELLIS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
134 AM EDT THU APR 16 2015
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP ALONG A FRONT STALLED ALONG THE GEORGIA
COAST TONIGHT...SLOWLY WEAKENING LATE THURSDAY AND FRIDAY. HIGH
PRESSURE OVER NEW ENGLAND WILL SHIFT EAST AND OFFSHORE THURSDAY. A
WARM FRONT WILL MOVE NORTH THROUGH THE CAROLINAS ON SUNDAY WITH A
COLD FRONT TO FOLLOW MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM THURSDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
THE WEATHER SITUATION IS UNFOLDING PRETTY MUCH AS EXPECTED. THE
SOLID MASS OF RAIN HAS CLEARED THE PEE DEE COUNTIES BUT RAIN
CONTINUES TO FALL ACROSS WHITEVILLE...SOUTHPORT AND WILMINGTON.
THIS AREA SHOULD MOVE OFF THE COAST IN THE NEXT 2 HOURS...LEAVING
MUCH WEAKER FORCING FOR THE OVERNIGHT NIGHT. LATEST HRRR AND HRRRMODELS
STILL SUGGEST THE BEST POTENTIAL FOR OVERNIGHT RAIN WILL BE NORTH
OF A LINE FROM FLORENCE TO DILLON...TO ELIZABETHTOWN AND
BURGAW...COINCIDENT WITH THE BETTER 700 MB MOISTURE AND RESIDUAL
ISENTROPIC LIFT ON THE SYNOPTIC MODELS. THERE IS ALSO SMALL
POSITIVE ELEVATED INSTABILITY ON THE ORDER OF 100 J/KG WHICH COULD
HELP SUPPORT SHOWERS GIVEN SUFFICIENT SYNOPTIC TRIGGERING. FEW
CHANGES ARE NEEDED TO LOW TEMPERATURE FORECASTS OR WINDS.
DISCUSSION FROM 730 PM FOLLOWS...
A STALLED FRONT JUST SOUTH OF SAVANNAH WILL DEVELOP AN AREA OF LOW
PRESSURE IN THE NEXT FEW HOURS. THIS LOW WILL NOT STRAY TOO FAR
OFFSHORE OVER THE NEXT 24 HOURS...BUT WILL MAINTAIN A STEADY
NORTHEAST WIND. SURFACE HIGH PRESSURE OVER SOUTHEASTERN CANADA
WILL SLIDE SOUTHEAST INTO NEW ENGLAND TONIGHT. THIS HIGH WILL
EXTEND A RIDGE AXIS SOUTHWARD INTO THE CAROLINAS...COMPRESSING THE
PRESSURE GRADIENT UP AGAINST THE LOW DEVELOPING OFF THE GEORGIA
COAST.
A COMPLEX UPPER LEVEL PATTERN ACROSS THE WESTERN U.S. HAS THE JET
STREAM SPLIT INTO TWO SEGMENTS. THE SOUTHERN STREAM WILL BRING
SEVERAL DISTURBANCES ACROSS THE CAROLINAS OVER THE NEXT 36-48
HOURS. ONE OF THESE DISTURBANCES IS MOVING ACROSS INTERSTATE 95
NOW PRODUCING THE LARGE SWATH OF RAIN NOW SEEN ON RADAR. THIS
FEATURE SHOULD WORK ITS WAY TO THE COAST AROUND MIDNIGHT...AND I
HAVE RAISED FORECAST POPS TO 100 PERCENT AREA-WIDE WITH 0.2 TO 0.4
INCHES OF RAIN EXPECTED OVER THE NEXT 12 HOURS. PLENTY OF MID-
LEVEL MOISTURE SHOULD HANG AROUND AFTER MIDNIGHT WITH JUST ENOUGH
WEAK ISENTROPIC LIFT PLUS ELEVATED INSTABILITY TO MAINTAIN SHOWERS
AFTER MIDNIGHT...ESPECIALLY NORTH OF FLORENCE AND MYRTLE BEACH.
LOW-LEVEL NORTHEAST WINDS WILL DRAG COOLER AIR SOUTHWARD
TONIGHT...WITH LOWS AWAY FROM THE COAST FALLING TO NEAR 50.
VARYING DEGREES OF MARINE INFLUENCE WILL KEEP THE IMMEDIATE COAST
WARMER WITH LOWS IN THE MID 50S POSSIBLE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...THE FORECAST HAS BECOME NO LESS COMPLICATED
AND IN FACT...IN SOME RESPECTS...MODELS HAVE DIVERGED EVEN FURTHER
IN THE LAST 24 HOURS. THE GFS SOLUTION LOOKS VERY DIFFERENT FROM
PREVIOUS RUNS. THE NAM SOLUTION LOOKS SIMILAR TO PREVIOUS
THINKING...BUT THE PROGRESSION OF OFFSHORE LOW PRESSURE IS SLOWER
AND FURTHER EASTWARD THAN 24 HOURS AGO AND CERTAINLY MUCH STRONGER.
THE CANADIAN IS CONSIDERABLY SLOWER AND WEAKER THAN THE NAM AS IS
THE EUROPEAN...BUT BOTH DO CLOSE OFF LOW PRESSURE ALONG THE COAST OF
SOUTH CAROLINA. SLOWER SEEMS REASONABLE GIVEN THE STRENGTH OF HIGH
PRESSURE TO THE NORTH AND RESULTING WEDGE...THUS THE BEST WE CAN DO
AT THIS POINT IS TO GO ALONG WITH PERSISTENCE...BUT SLOW PROGRESSION.
WILL INCLUDE HIGHEST POPS THU ALONG THE COAST AND UP TO CATEGORICAL
THU MORNING ALONG THE CAPE FEAR COAST DUE TO STRENGTH OF ISENTROPIC
LIFT COUPLED WITH THE LIFT ASSOCIATED WITH LOW PRESSURE/TROUGH. WILL
THEN TREND POPS LOWER THU AFTERNOON AND NIGHT FROM SW TO NE WITH A
LINGERING RISK ALONG THE CAPE FEAR COAST FRI MORNING. GIVEN
PROXIMITY OF COASTAL TROUGH AND ELEVATED INSTABILITY...WILL INCLUDE
MENTION OF THUNDER FOR PORTIONS OF THE FORECAST AREA.
THE MOISTURE PROFILES DRY OUT CONSIDERABLY AS A RIDGE OF HIGH
PRESSURE ALOFT BUILDS TO THE COAST FROM THE WEST TOWARD THE END OF
THE PERIOD. WILL FINALLY DROP POPS BELOW THRESHOLD FRI AFTERNOON AND
NIGHT...EVEN ALONG THE SEABREEZE BOUNDARY.
BELOW NORMAL HIGH TEMPS ARE EXPECTED AGAIN ON THU AS WEDGE KEEPS LOW-
LEVEL MOISTURE TRAPPED BENEATH INVERSION. HIGHS WILL ONLY BE IN THE
LOWER TO MID 60S. DEVELOPING SUNSHINE ON FRI SHOULD ALLOW TEMPS TO
RETURN TO MORE SEASONABLE LEVELS...LOW AND MID 70S. LOWS THIS PERIOD
WILL BE MAINLY IN THE 50S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...GUIDANCE HAS SHIFTED PRETTY DRAMATICALLY
FROM JUST YESTERDAY...LEADING TO ENHANCED UNCERTAINTY DURING THE
EXTENDED. LARGE CLOSED LOW ACROSS THE SOUTHWEST WILL ONLY VERY
SLOWLY FILL AND EJECT TO THE NORTHEAST THROUGH THE WEEKEND...PHASING
WITH A DEEPENING NORTHERN STREAM CUTOFF LOW ACROSS THE GREAT LAKES
LATE MONDAY. THIS FEATURE WILL THEN AMPLIFY AND STALL ACROSS THE
GREAT LAKES THROUGH THE MIDDLE OF NEXT WEEK...PRODUCING 500MB
HEIGHTS OF -2 TO -3 SD`S BELOW CLIMO ACROSS THE NORTHEAST AND INTO
THE MID-ATLANTIC.
INITIALLY THE EXTENDED WILL BE WARM AND PLEASANT. SATURDAY IS
SHAPING UP TO BE A GORGEOUS DAY LOCALLY...WITH HIGHS ABOVE CLIMO AND
A LOT OF SUNSHINE. MOISTURE RETURNS SUNDAY IN A PRE-FRONTAL AIR MASS
WHICH WILL CONTINUE INTO MONDAY AHEAD OF A COLD FRONT. SUNDAY AND
MONDAY WILL BOTH FEATURE ABOVE CLIMO TEMPS...BUT WITH INCREASING
RAIN CHANCES AHEAD OF THE COLD FRONT. ATTM THE FRONT DOES NOT LOOK
TO BE STRONGLY FORCED SO WIDESPREAD CONVECTION IS NOT ANTICIPATED
MONDAY EVENING WITH THE FROPA. COOLER HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT FOR TUE/WED OF NEXT WEEK WITH TEMPS RETURNING TO
SEASONABLE LEVELS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...EXPECTING IFR CONDITIONS MUCH OF THE TAF PERIOD WITH
OCCASIONAL RAIN. COULD BE A BREAK IN THE 20 TO 02Z WINDOW WITH
MVFR OR VFR CONDITIONS UNTIL THE NEXT BATCH OF PRECIPITATION
ARRIVES TOWARD THE END OF THE PERIOD. WITH LOW PRESSURE OFF THE
COAST...GUSTY NE WINDS ARE EXPECTED THROUGH MUCH OF THE PERIOD AS
WELL WITH SPEEDS IN THE 10 TO 15 KT RANGE WITH WITHS OVER 20
KT...ESPECIALLY COASTAL TERMINALS.
EXTENDED OUTLOOK...PREDOMINATELY IFR CONDITIONS ARE EXPECTED INTO
EARLY FRIDAY MORNING WITH THE WEDGE. IMPROVING CONDITIONS DURING THE
DAY FRI. DETERIORATING CONDITIONS AGAIN SATURDAY NIGHT THROUGH
SUNDAY WITH A SLOW MOVING FRONT. SLIGHT CHANCE FOR SHOWERS MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
STRONG NE WINDS HAVE QUICKLY DEVELOPED THIS EVENING. RECENT WIND
GUSTS INCLUDE 31 KNOTS AT SPRINGMAID PIER IN MYRTLE BEACH...24
KNOTS ON BALD HEAD ISLAND...AND 23 KNOTS AT WRIGHTSVILLE BEACH.
SEAS OUT AT THE FRYING PAN SHOALS BUOY HAVE ALREADY REACHED 8
FEET...WITH SEAS NOW PASSING 5 FEET AT BOTH NEARSHORE BUOYS NEAR
CAPE FEAR. THIS UPDATE BACKED WINDS AROUND MORE NORTHERLY
NEARSHORE AND INCREASE SEA HEIGHTS SLIGHTLY...ALL BASED ON CURRENT
OBSERVATIONS. DISCUSSION FROM 730 PM FOLLOWS...
A FRONT STALLED JUST SOUTH OF SAVANNAH EXTENDS EAST WELL OFF THE
COAST. WEAK LOW PRESSURE WILL DEVELOP ALONG THE FRONT
TONIGHT...WHILE HIGH PRESSURE OVER NEW ENGLAND RIDGES SOUTHWARD
DOWN THE COAST. THE CAROLINAS WILL BE CAUGHT IN BETWEEN THESE TWO
SYSTEMS...WITH INCREASING EAST-NORTHEAST WINDS THE RESULT.
THE 18Z GFS APPEARS TO BE THE BEST INITIALIZED OF OUR MODELS THIS
EVENING...AND ITS FORECAST WINDS HAPPEN TO BE THE STRONGEST
TONIGHT...INDICATING WINDS NEARSHORE INCREASING TO 20-25 KT AND
25-30 KT AWAY FROM SHORE. THIS IS SLIGHTLY HIGHER THAN THE
PREVIOUS FORECAST HAD. LATEST CHECK OF BUOYS INDICATES SEAS ARE
INCREASING A BIT FASTER THAN EARLIER THOUGHT. I HAVE ADDED ABOUT
ONE FOOT TO THE PREVIOUS FORECAST...WITH SEAS NOW EXPECTED TO
BUILD TO 6-8 FEET OUT AT 20 MILES DISTANCE FROM SHORE...WITH 4-7
FEET EXPECTED CLOSER TO SHORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...ONGOING SMALL CRAFT ADVISORY CONDITIONS ARE
EXPECTED AT THE BEGINNING OF THE PERIOD AS LOW PRESSURE MOVES UP THE
SOUTHEAST COAST. THE PRESSURE GRADIENT BETWEEN DEVELOPING LOW
PRESSURE AND THE STRONG HIGH TO THE NORTH WILL ALLOW A TIGHT
PRESSURE GRADIENT TO PERSIST INTO THU AND THIS IS WHEN WE EXPECT THE
STRONGEST WINDS AND HIGHEST SEAS...UP TO 20 TO 30 KT...HIGHEST
NORTHERN WATERS AND SEAS UP TO 5 TO 8 FT THROUGHOUT. AS THE PRESSURE
GRADIENT SLACKENS AND LOW PRESSURE MOVES TO OUR N...WINDS AND SEAS
WILL SUBSIDE THU NIGHT AND FRI WITH THIS TREND PERSISTING INTO FRI
NIGHT. ENE WINDS THU WILL BACK TO NE THU NIGHT WITH NNE TO NE
WINDS THEN PERSISTING THROUGH THE END OF THE PERIOD.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...HIGH PRESSURE WILL BUILD DOWN THE COAST AND
THEN MOVE OFFSHORE SATURDAY...CREATING A WEAK PRESSURE GRADIENT AND
WINDS SHIFTING FROM NE EARLY...TO E/SE LATE. WINDS SPEEDS THEN
STEADILY INCREASE SUNDAY AS THE GRADIENT STARTS TO PINCH AHEAD OF AN
APPROACHING COLD FRONT...BECOMING S/SW AT AROUND 15 KTS MOST OF
SUNDAY...AND THEN SW AT 15-20 KTS ON MONDAY DIRECTLY AHEAD OF THE
FROPA. COLD FRONT WILL CROSS THE WATERS AT THE VERY END OF THE
PERIOD WITH A WIND SHIFT TO THE NW AT 10-15 KTS. ALTHOUGH A WEAK SE
GROUND SWELL WILL BE PRESENT IN THE SPECTRUM DURING THE
EXTENDED...MUCH OF THE WAVE AMPLITUDE WILL BE FORMED VIA WIND
WAVES...AND SEAS WILL BE 2-3 FT SATURDAY...BUILDING TO 3-5 FT SUNDAY
AND MONDAY AHEAD OF THE COLD FRONT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ250-252-254-
256.
&&
$$
SYNOPSIS...RJD
NEAR TERM...REK/TRA
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...RAN
MARINE...REK/RJD/TRA/JDW
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1227 AM CDT THU APR 16 2015
.UPDATE...
ISSUED AT 1227 AM CDT THU APR 16 2015
MINOR CHANGES THIS UPDATE. KEPT CHANCES OF RAIN SHOWERS
SOUTHWEST...BUT APPARENT FORCING ALONG THE SLOW-MOVING COLD FRONT IN
CENTRAL NORTH DAKOTA IS NOT ENOUGH TO SUSTAIN SHOWERS. MINOR CHANGES
IN HOURLY TEMPERATURE TRENDS.
UPDATE
ISSUED AT 923 PM CDT WED APR 15 2015
RADAR ECHOS ACROSS THE FAR SOUTHWEST...OTHERWISE DRY SO ONCE AGAIN
SCALED BACK ON POPS FOR THIS UPDATE. OTHER EDITS MINOR.
UPDATE
ISSUED AT 808 PM CDT WED APR 15 2015
WILL ALLOW THE RED FLAG TO EXPIRE AS SCHEDULED WITH WINDS TAPERING
OFF AND RH VALUES QUICKLY INCREASING.
UPDATE
ISSUED AT 720 PM CDT WED APR 15 2015
SCALED BACK ON POPS A BIT WITH A VOID OF ANY SORT OF DECENT RADAR
RETURNS ACROSS NORTH DAKOTA. ALLOWED THE WIND ADVISORY TO EXPIRE
AS WE ARE NOW BELOW ADVISORY CRITERIA EAST...AND WITH WINDS
EXPECTED TO QUICKLY TAPER OFF FURTHER OVER THE NEXT HOUR OR SO.
STRONG UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN JUST WEST OF THE
CENTRAL ROCKIES. ENERGY ROTATING AROUND THE LOW WILL SPIRAL NORTH
ACROSS THE WESTERN DAKOTAS AND SHOULD BRING SOME LIGHT RAIN. BAND
OF ENHANCED RADAR RETURNS CURRENTLY LIFTING NORTH ACROSS WESTERN
SOUTH DAKOTA TOWARDS MY SOUTHWEST. WITH T/TD SPREADS
20-30F...WILL KEEP POPS BELOW LIKELY FOR NOW AND CONTINUE TO
MONITOR.
RED FLAG WARNING WILL BE ALLOWED TO EXPIRE AT 01Z...ROUGHLY 45-50
MINUTES FROM NOW...AS WINDS TAPER OFF AND RH VALUES INCREASE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 251 PM CDT WED APR 15 2015
FIRE WEATHER CONCERNS HIGHLIGHT THE SHORT TERM TONIGHT BUT WILL
DIMINISH TOMORROW. A COLD FRONT ACROSS WESTERN NORTH DAKOTA HAS
BEEN SLOWER TO MOVE EAST THAN EARLIER FORECAST. THE RESULT HAS
BEEN AN EXTENDED PERIOD OF GUSTY SOUTHERLY WINDS ACROSS CENTRAL
AND EASTERN NORTH DAKOTA UP THROUGH THIS AFTERNOON. THIS HAS
RESULTED AN MULTIPLE FIRES ACROSS CENTRAL NORTH DAKOTA. IMPROVING
CONDITIONS WILL FINALLY ARRIVE THIS EVENING AS THE FRONTAL
BOUNDARY MOVES TO CENTRAL NORTH DAKOTA THEN TO THE EAST AFTER
MIDNIGHT. THIS WILL BRING AN END TO THE STRONG SOUTHERLY WINDS.
CLOUDS ARE BEING DRAWN UP THROUGH EASTERN SOUTH DAKOTA WITH SOME
LIMITED LOW LEVEL MOISTURE. THE HRRR DOES GENERATE SOME LIGHT
PRECIP ACROSS THE EAST...BUT GENERALLY EAST OF THE JAMES RIVER
VALLEY THOUGH.
MEASURABLE PRECIPITATION WILL BE MOST LIKELY ACROSS THE SOUTHWEST
TONIGHT. BUT KEPT THE POPS LESS THAN 40 PERCENT.
ON THURSDAY...COOLER TEMPERATURES WITH HIGHS 60 TO 65.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 251 PM CDT WED APR 15 2015
A WEAK COLD FRONTAL BOUNDARY SHIFTING THROUGH NORTHERN NORTH DAKOTA
LATE THURSDAY NIGHT WILL UNDERGO FRONTOLYSIS AS IT SAGS SOUTH INTO
CENTRAL NORTH DAKOTA FRIDAY MORNING. SPLIT FLOW REMAINS OVER NORTH
DAKOTA FRIDAY WITH THE NORTHERN STREAM JUST GRAZING FAR NORTHERN
NORTH DAKOTA/TURTLE MOUNTAINS. A CLOSED LOW OVER COLORADO SLOWLY
EMERGES INTO THE CENTRAL PLAINS...WITH NORTH DAKOTA CAUGHT BETWEEN
THESE TWO STREAMS FRIDAY AND WILL MOSTLY REMAIN IN A LULL FRIDAY
WITH BENIGN WEATHER. FOR SATURDAY AND SATURDAY NIGHT...MODEL DATA
CONTINUES TO SUGGEST SOME INTERACTION WITH THE CLOSED LOW AND ITS
ASSOCIATED MOISTURE SPINNING INTO SOUTHERN NORTH DAKOTA...AND A
STRONG SHORTWAVE TROUGH/SURFACE COLD FRONT VIA THE NORTHERN STREAM
AS IT APPROACHES WESTERN NORTH DAKOTA 00Z SUNDAY. VARYING SOLUTIONS
AS TO THE TIMING AND AREAL COVERAGE OF PRECIPITATION THAT IS
FORECAST TO PUSH INTO NORTH DAKOTA SATURDAY AFTERNOON INTO SATURDAY
NIGHT. THE GFS REPRESENTS THE FASTEST AND MOST WIDESPREAD
PRECIPITATION SOLUTIONS...WITH CHANCES OF RAIN CROSSING THE SOUTHERN
BORDER BEFORE 12Z SATURDAY. THE GEM/ECMWF REPRESENT SLOWER SOLUTIONS
AND ARE MORE IN LINE WITH RAIN SHOWERS MAINLY CONFINED TO THE JAMES
RIVER VALLEY AND PORTIONS OF SOUTH CENTRAL NORTH DAKOTA LATE
SATURDAY AFTERNOON THROUGH SUNDAY MORNING. A COLD THERMAL
TROUGH/POCKET IS FORECAST TO FOLLOW SUNDAY NIGHT THROUGH MOST OF
NEXT WEEK. GOOD AGREEMENT BETWEEN THE GFS AND ECMWF WITH THIS IDEA.
850MB TEMPS ARE FORECAST TO RANGE BETWEEN -2C TO -8C THROUGH
THURSDAY. THIS WILL TRANSLATE TO AFTERNOON HIGH TEMPERATURES IN THE
UPPER 40S TO MID 50S.
CONCERNING FIRE WEATHER IN THE LONG TERM PERIOD...NOT ANTICIPATING
ANY FIRE WEATHER CONCERNS FRIDAY OR SATURDAY. DESPITE A COOLING
TREND SUNDAY ONWARD...STRONG WINDS AT TIMES WILL ALIGN WITH LOW
RELATIVE HUMIDITIES ACROSS PORTIONS OF WESTERN AND CENTRAL NORTH
DAKOTA AND WILL NEED TO MONITOR. STRONG NORTHWEST WINDS DEVELOPING
BEHIND A COLD FRONT ACROSS WESTERN AND CENTRAL NORTH DAKOTA SUNDAY
MAY WARRANT A WIND ADVISORY. IN ADDITION MINIMUM RELATIVE HUMIDITIES
OF AROUND 25 PERCENT IN THE SOUTHWEST MAY ALSO WARRANT A FIRE
WEATHER HEADLINE SUNDAY. THEN ON MONDAY THE STRONGEST WINDS AND
LOWEST RELATIVE HUMIDITIES ARE ALIGNED IN SOUTH CENTRAL NORTH
DAKOTA...THUS THIS REPRESENTS ANOTHER POTENTIAL FOR FIRE WEATHER
HEADLINES. WEAKER WINDS ARE EXPECTED FOR TUESDAY AND WEDNESDAY WITH
EVEN COOLER TEMPERATURES...WITH WIDESPREAD HIGHS IN THE 40S
WEDNESDAY. NO SIGNIFICANT SYSTEMS/PRECIPITATION EVENTS SUNDAY
THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1227 AM CDT THU APR 16 2015
A COLD FRONT EXTENDED FROM NEAR BOTTINEAU/RUGBY TO NEAR KBIS TO KMBG
WAS SLOWLY PROPAGATING EASTWARD ACROSS THE STATE. SOUTHERLY WINDS AT
KJMS SHOULD BECOME NORTHWESTERLY AROUND 12Z. OTHERWISE NORTH TO
NORTHWEST WINDS AT TAF SITES MUCH OF TODAY...BECOMING LIGHT AFT 00Z.
VFR CIGS/VSBYS ARE EXPECTED THROUGHOUT THE PERIOD.
&&
.FIRE WEATHER...
ISSUED AT 808 PM CDT WED APR 15 2015
RED FLAG WARNING ALLOWED TO EXPIRE WITH COOLING TEMPERATURES AND
RISING RELATIVE HUMIDITY. ON THURSDAY MINIMUM RELATIVE HUMIDITY
WILL FALL INTO THE UPPER TEENS NORTHWEST. HOWEVER THE WINDS WILL
BE MUCH LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...KS
AVIATION...JV
FIRE WEATHER...NH
AREA FORECAST DISCUSSION
NWS NORMAN OK
334 PM CDT THU APR 16 2015
.DISCUSSION...
THIS DISCUSSION WILL REMAIN FOCUSED ON THE SHORT TERM...
THUNDERSTORM AND PRECIPITATION CHANCES FROM THIS EVENING THROUGH
FRIDAY MORNING...
OVERALL... GUIDANCE HAS DONE A POOR JOB IN HANDLING THE BKN/OVC
LOW/MID STRATUS ACROSS THE BULK OF WRN AND CENTRAL OK AND WRN N TX.
THROUGH 20Z... SOME SCATTERED CLEARING HAS FINALLY STARTED AS MORE
STRATOCU/CLOUD STREETS HAVE DEVELOPED. THIS CLOUD COVER WILL
CONTINUE TO PROMOTE A LACK OF INSTABILITY/BL MIXING ACROSS MOST OF
WRN OK AND WRN N TX... BUT WITH THE RECENT TRANSITION TO STRATOCU...
MIXING MAY FINALLY BE PICKING UP. THE EARLY AFTN CONVECTION ACROSS
FAR NW OK AND INTO THE PANHANDLES APPEARED TO BE DRIVEN BY A FOCUSED
REGION OF ISENTROPIC ASCENT... SUPPORTED BY A NARROW REGION OF 1500
J/KG INSTABILITY AND DIVERGENCE ALOFT GIVEN THE ORIENTATION OF THE
UPPER LVL JET MAX ASSOCIATED WITH THE H500 LOW... WHICH CONTINUES TO
SETTLE OVER THE FOUR CORNERS REGION. THE RECENT SEVERE CONVECTION IN
THE PANHANDLES THAT DEVELOPED OVER THE PAST 1 TO 2 HOURS IS
PRIMARILY FOCUSED ON THE DRYLINE/PSUEDO-FRONTAL BOUNDARY THAT
DEVELOPED EARLIER.
AT THE MOMENT... HOW CONVECTION WILL EVOLVE THROUGH THIS EVENING
REMAINS A CHALLENGE. TRADITIONAL GUIDANCE CONTINUES TO STRUGGLE WITH
HOW TO EVOLVE THE UPPER LOW AND CONVECTION. RECENT MESOSCALE
GUIDANCE IS ABLE TO CATCH ON IN SPURTS... BUT IT STRUGGLES AS WELL.
OVERALL... EXPECT CONVECTION ACROSS THE PANHANDLES TO CONTINUE TO
TRANSITION EASTWARD... HOWEVER... RECENT OBS THROUGH 20Z SUGGEST THE
DRYLINE MAY BE STARTING ITS GRADUAL RETREAT TO THE WEST. WITH THIS
SAID... EXPECT THE SFC TROUGH/FRONT (IF WE CAN CALL IT THAT)... WILL
CONTINUE TO LIFT E/NE INTO WRN OK THIS EVENING... WITH STORMS MOVING
INTO NWRN OK AROUND 5 TO 7PM CDT. THE OVERALL EVOLUTION OF STORMS
APPEAR TO HAVE BEEN CAPTURED ON THE RECENT HRRR (18Z RUN)... BUT THE
TIMING MAY BE LATE... THE 12Z TTU WRF SEEMS TO HAVE A DECENT HANDLE
ON TIMING... AS DOES THE WRF-NMM. NOT TO FOCUS SOLELY ON THE WRN
ACTIVITY... STRONG CONVECTION HAS DEVELOPED ACROSS WEST CENTRAL TX
THIS AFTN. CURRENT THOUGHTS HAVE THIS ACTIVITY LIFTING N/NE INTO WRN
N TX AND THE RED RIVER VALLEY. RECENT MESOSCALE GUIDANCE SEEMS TO
SUGGEST THIS ACTIVITY WILL LESSEN AFTER SUNSET AS IT REMAINS DRIVEN
BY DIURNAL HEATING/INSTABILITY.
AS FOR SEVERE STORMS THIS AFTN/EVENING ACROSS WRN OK/WRN N TX...
STORMS THAT ARE ABLE TO MOVE IN OR DEVELOP WILL RESIDE WITHIN AN
ENVIRONMENT SUPPORTIVE OF LARGE HAIL (GOLF BALLS) AND DAMAGING WINDS
(60-70MPH). SEVERE POTENTIAL WILL WANE WITH ANY SCATTERED CONVECTION
THAT PERSISTS INTO THE OVERNIGHT HOURS EASTWARD INTO CENTRAL OK BY
FRIDAY MORNING. THE TORNADO THREAT OVER THE TX PANHANDLE WILL
DIMINISH AS STORMS MOVE OFF THE DRYLINE AND INTO WRN OK... 0-1KM
HELICITY DECREASES AND THE LACK OF A FOCUSING BOUNDARY DOES NOT BODE
WELL FOR TORNADIC DEVELOPMENT ACROSS WRN OK AT THE MOMENT.
JTK
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 59 74 59 77 / 40 50 60 30
HOBART OK 57 75 55 77 / 50 50 50 20
WICHITA FALLS TX 60 77 58 80 / 40 50 50 20
GAGE OK 54 74 51 76 / 70 50 50 20
PONCA CITY OK 58 74 58 75 / 30 60 70 50
DURANT OK 61 77 62 78 / 30 50 60 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1044 PM EDT FRI APR 17 2015
.SYNOPSIS...
DRIER AND WARMER AIR WILL SPREAD INTO THE REGION THROUGH SATURDAY. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT INTO
SUNDAY...ACCOMPANIED BY ABUNDANT MOISTURE AND MORE RAINFALL. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...USHERING IN SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 PM EDT FRIDAY...WIDESPREAD SHOWERS STILL COVER THE
UPSTATE AND PORTIONS OF THE MOUNTAINS...SO CONTINUING CATEGORICAL
POPS FOR ANOTHER COUPLE OF HOURS UNTIL THE SHORTWAVE AXIS PUSHES
THROUGH STILL LOOKS GOOD. TEMPERATURES ON TRACK FOR THE MOST PART SO
ONLY MINOR TWEAKS TO HOURLY TRENDS.
AS OF 730 PM EDT FRIDAY...HAVE BUMPED UP POPS ACROSS MOST OF THE
AREA THIS EVENING INTO THE OVERNIGHT PERIOD TO ACCOUNT FOR FAIRLY
WIDESPREAD LIGHT RAIN/SHOWERS MOVING ACROSS THE AREA...FORCED BY THE
RELATIVELY STRONG SHORTWAVE MOVING ACROSS THE SOUTHEAST THIS
EVENING. IF THE HRRR IS TO BE BELIEVED...THESE SHOWERS COULD LINGER
OVERNIGHT AND PAST SUNRISE...AND WILL EVALUATE FURTHER FOR THE LATE
EVENING UPDATE. BEST MOISTURE REMAINS ACROSS THE UPSTATE AND
NORTHEAST GEORGIA BUT STILL SEEING SOME LIGHT RAIN ACROSS THE
MOUNTAINS AND FOOTHILLS. STILL SEEING SOME SBCAPE VALUES HOLDING ON
ACROSS THE PIEDMONT BUT THESE SHOULD BEGIN DROPPING RAPIDLY WITH
SUNSET...SO HAVE PULLED BACK ON THUNDER WORDING THIS EVENING AND
OVERNIGHT. OTHER GRIDS IN GOOD SHAPE FOR THE MOST PART...WITH ONLY
MINOR TWEAKS TO ACCOUNT FOR HOURLY TRENDS.
AS OF 430 PM EDT FRIDAY...VERY LITTLE CHANGE TO PREVIOUS THINKING
FOR THE NEAR TERM. PRECIPITATION BEGINNING TO OVERSPREAD WESTERN AND
SOUTHWESTERN ZONES AS EXPECTED. NEW GUIDANCE BEGINNING TO PULL BACK
A LITTLE ON CONVECTIVE POTENTIAL...WITH INCREASING CLOUD COVER AND
MOISTENING ATMOSPHERE WHAT LITTLE SBCAPE WAS BEGINNING TO CREEP INTO
THE MESOANALYSES OVER THE PAST COUPLE OF HOURS IS ONCE AGAIN FALLING
OFF. LOOKING AT HI-RES REFLECTIVITY FORECASTS...DEFINITELY STARTING
TO LOOK LIKE MORE STRATIFORM RAIN OR SHOWERS WITH THE POSSIBILITY OF
EMBEDDED THUNDER. HAVE LEFT WEATHER WORDING AS IS FOR NOW SINCE
CURRENTLY ADVERTISED THUNDER IS CHANCE AT BEST...BUT WILL REEVALUATE
MORE THOROUGHLY FOR NEXT NEAR-TERM UPDATE. ONLY MINOR TWEAKS TO
TEMPS AND DEWPOINTS TO UPDATE TRENDS.
AS OF 245 PM EDT FRIDAY...THE SYNOPTIC PATTERN HAS NOT CHANGED ALL
THAT MUCH FROM YESTERDAY...OR DAYS PAST FOR THAT MATTER. IT STILL
FEATURES ROTATING CLOSE UPPER LOW OVER THE FOUR CORNERS WHILE DEEP
SOUTHWEST WAA PREVAILS ACROSS THE SOUTHEAST UNITED STATES. AT
THE SURFACE...SPRINGTIME WEDGE STARTING TO ERODE AS EXPECTED THIS
AFTERNOON AS WINDS HAVE VEERED SOUTHERLY ACROSS NORTHEAST GA AND THE
UPSTATE...ALONG WITH A FEW LOCATIONS OVER THE NC PIEDMONT.
FURTHERMORE...H5 SHORT WAVE AND ASSOCIATED VORTICITY MAXIMA
CONTINUES TO SLIDE EAST ACROSS THE DEEP SOUTH WITH A BROAD AREA OF
PRECIPITATION ACCOMPANYING. LATEST SPC MESO ANALYSIS NOT ALL THAT
IMPRESSIVE AS INSTABILITY REMAINS NEARLY NONEXISTENT ACROSS THE FCST
AREA. MODELS FAVOR IMPROVING LAPSE RATES WITH HEATING THIS
AFTERNOON...HOWEVER STILL SKEPTICAL AS PRECIP SHIELD AND ASSOCIATED
LOW OVERCAST SKY COVER WILL LIMIT HEATING. NEVERTHELESS...THE FCST
DOES FEATURE INCREASING POPS THROUGH THE AFTERNOON/EVENING HOURS
WITH CHANCES FOR THUNDER MENTIONED...AND WILL CONTINUE WITH SUCH IN
THE HWO. POPS WILL LOWER AFTER MIDNIGHT AS THE PRIMARY UPPER WAVE
EJECTS TO THE EAST...AND A WEAK/DRY BACK DOOR FRONT SLIDES SOUTHWARD
ACROSS THE REGION. HELD ON TO TOKEN SLIGHT/CHANCE POPS THROUGH
MORNING TO ACCOUNT FOR ANY RESIDUAL SHRA ALONG THE BOUNDARY. LATEST
SOUNDINGS DO NOT SUGGEST AS MUCH MID DRYING AS THE PREVIOUS
RUN...THEREFORE NOT ALL THAT CONFIDENT IN AREAS OF DENSE FOG
OVERNIGHT. THAT SAID...WOULDNT BE SURPRISED TO SEE ISOLATED CASES OF
SUCH ACROSS THE NC PIEDMONT/FOOTHILLS JUST AHEAD OF THE INTRUDING
BOUNDARY WHEN WINDS ARE CALMEST AND THE PBL IS DECOUPLED.
SATURDAY WILL BE HIGHLIGHTED BY DECREASING CLOUDINESS AS DOWNSLOPING
FLOW PREVAILS AMONGST INCREASING HEIGHTS ALOFT AS AXIS OF SHORTWAVE
RIDGE SHIFTS OVERHEAD. POPS WILL INCREASE YET AGAIN THROUGH THE DAY
AS FCST SOUNDINGS INDICATE MODEST DESTABILIZATION WITH HEATING.
HOWEVER EXPECTING UPPER RIDGING TO PROVIDE SOME SUBSIDENCE THEREFORE
KEPT POPS AT OR BELOW CHANCE LEVELS THROUGH THE DAY. TEMPERATURES
ON SATURDAY WILL DEPEND HIGHLY ON HOW SOON THE SKY COVER SCT OUT.
TOOK A MIDDLE OF THE ROAD APPROACH AS IT PERTAINS TO GUIDANCE...WITH
THE FCST FEATURING HIGHS 3-5 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRIDAY...TWO AREAS OF CONCERN TO DEAL WITH IN THE SHORT
TERM. THE FIRST WILL BE A PERIOD OF HEAVY RAIN ON SUNDAY AND THEN A
RISK OF SEVERE STORMS ON MONDAY.
THE UPPER RIDGE OVER THE SOUTHEAST U.S. WILL TRANSLATE EASTWARD
SATURDAY NIGHT AS THE UPPER LOW THAT HAS BEEN OVER THE 4-CORNERS
BEGINS TO MOVE EAST THANKS TO A DIGGING TROUGH MOVING SE OUT OF THE
CANADIAN PRAIRIE. A SHORT WAVE OUT AHEAD OF THE UPPER LOW WILL
MOVE NE FROM THE GULF COAST AND ACROSS THE WESTERN CAROLINAS AND
NE GA ON SUNDAY. AT THE SURFACE...A WARM FRONT WILL APPROACH FROM
THE SW ON SUNDAY. ALL OF THIS WILL RESULT IN ALL TYPES OF FORCING
ACROSS THE REGION ON SUNDAY. PWATS WILL BE IN THE 1.5-1.7" RANGE
WITH A 35-45 KT SELY 850 MB JET INTO THE BLUE RIDGE. WILL RAMP
POPS UP QUICKLY TO CATEGORICAL FROM WEST TO EAST BY MIDDAY
SUNDAY...THEN DECREASE RAPIDLY FROM WEST TO EAST LATE SUNDAY AS
THE AXIS OF DEEP MOISTURE AND FORCING SHIFT EAST. HEAVY RAIN LOOKS
TO BE A GOOD BET...BUT THE RELATIVELY QUICK MOVEMENT OF THE SYSTEM
SHOULD PRECLUDE ANY SERIOUS HYDRO ISSUES. BLENDING THE MODEL
CONSENSUS AND WPC QPF GUIDANCE... RESULTS IN GENERALLY 1.5"-2.0"
FROM LATE SATURDAY NIGHT INTO SUNDAY NIGHT. THE HIGHEST AMOUNTS AS
USUAL ARE EXPECTED TO BE NEAR THE BLUE RIDGE ESCARPMENT WHERE 2-3"
OF RAIN CAN BE EXPECTED. THESE VALUES ARE UNDER THE 12 TO 24 HOUR
FFG. THERE MAY BE SOME LOCALIZED FLOODING BUT WIDESPREAD FLOODING
IS UNLIKELY. HOWEVER...WILL CONTINUE TO MENTION HEAVY RAIN IN THE
HWO. AN IN SITU WEDGE WILL RESULT IN COOL TEMPS ON SUNDAY AND WILL
THEREFORE TREND TOWARD CONSRAW GUIDANCE TEMPS.
SOME DEGREE OF CLEARING SHOULD OCCUR SUNDAY NIGHT AS THE AXIS OF
DEEP MOISTURE SHIFTS NE AND A DOWNSLOPE WIND COMPONENT THROUGH THE
COLUMN DEVELOPS. ON MONDAY...A COLD FRONT WILL MOVE ACROSS THE
REGION FROM WEST TO EAST. BOTH THE NAM AND GFS INDICATE THAT THE
ATMOSPHERE WILL DESTABILIZE BY AFTERNOON WITH CAPES MOST LIKELY
INCREASING TO BETWEEN 1000 AND 1500 J/KG PER GFS AND ECM.
ALSO...0-6KM SHEAR INCREASES TO ABOUT 40KT. THIS MAY SUPPORT SOME
ORGANIZATION TO THE CONVECTION AS THE COLD FRONT MOVES THROUGH.
THE 12Z NAM MODEL REFLECTIVITY SUGGESTS THAT A BROKEN LINE OF
CONVECTION WILL ACCOMPANY THE FRONT ACROSS THE AREA ON MONDAY WITH
A FEW SEVERE STORMS POSSIBLE. WITH THE AREA SOLIDLY IN THE WARM
SECTOR ON MONDAY...MAX TEMPS ARE EXPECTED TO BE ABOUT 5 DEGREES
ABOVE CLIMO.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM FRIDAY...MONDAY NIGHT...SFC HIGH PRESSURE WILL BUILD
OVER THE FORECAST AREA IN THE WAKE OF A PASSING COLD FRONT. 12Z GFS
INDICATES THAT H85 TEMPERATURES WILL COOL BY 5 C FROM 0Z TO 12Z
TUESDAY...A LITTLE LESS COOLING ON THE ECMWF. USING A BLEND OF
GUIDANCE...I WILL FORECAST LOW TEMPERATURES FROM THE UPPER 40S
WITHIN THE MTN VALLEYS TO MID 50S EAST. ON TUESDAY...BROAD HIGH
PRESSURE WILL REMAIN ACROSS THE CWA. THE REGION SHOULD SEE MOSTLY
SUNNY CONDITIONS WITH A LIGHT SOUTHWEST WIND. TEMPERATURES SHOULD
RESPOND TO THE LATE APRIL SUN AND WEAK DOWNSLOPING...FORECAST TUES
HIGHS SLIGHTLY ABOVE NORMAL.
WEDNESDAY THROUGH FRIDAY...THE GFS AND ECMWF GENERALLY AGREE THAT A
LARGE CLOSED MID LEVEL LOW WILL REMAIN ACROSS THE NORTHEAST AND
EASTERN CANADA...AS A RIDGE LINGERS OVER THE SOUTHERN PLAINS. THE
HEIGHTS ACROSS THE CWA WILL LIKELY REMAIN NW TO SE THROUGH THE
PERIOD. THE MODELS ARE IN LESS AGREEMENT WITH THE PLACEMENT AND
TIMING OF SFC FEATURES...PRIMARILY WEAK FRONTS AND PRESSURE CENTERS.
I AM MORE CONFIDENT TIMING MID LEVEL FEATURES WITHIN THE NW FLOW
ACROSS THE SOUTHERN APPALACHIANS...I WILL FAVOR THE ECMWF.
OVERALL...I WILL KEEP CONDITIONS DRY ON WED...BUT MOISTURE WILL
INCREASE THROUGH THE DAY. A SHORT SERIES OF MID LEVEL S/W ARE
FORECAST TO RIPPLE ACROSS THE CWA THURSDAY THROUGH FRIDAY.
TEMPERATURES SHOULD RANGE CLOSE TO NORMAL WITH AFTERNOON DEWPOINTS
ONLY IN THE 40S. GIVEN THE TRACK OF THE MID LEVEL DISTURBANCES AND
WEAK DIURNAL INSTABILITY...I WILL INDICATE ONLY SCHC POPS ACROSS THE
MTNS ON THURSDAY. FORECAST SOUNDINGS SHOW GREATER INSTABILITY FRIDAY
AFTERNOON...FROM THE MTNS TO THE PIEDMONT. THE COMBINATION OF THE
PASSING DISTURBANCE AND INSTABILITY SHOULD SUPPORT SCT COVERAGE
ACROSS THE MTNS AND ISO EAST.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT /03Z UPDATE/...CIGS A LITTLE SLOWER TO DROP THAN EARLIER
ANTICIPATED SO HAVE DELAYED THE MVFR CIGS FOR ANOTHER HOUR OR
SO...WITH -RA/-SHRA SLOWLY PUSHING EAST TOWARD THE AIRPORT UNDER THE
INFLUENCE OF THE UPPER SHORTWAVE. ONCE THE DEEPER MOISTURE
ARRIVES...CIGS SHOULD DROP TO MVFR. AS WINDS DECOUPLE
OVERNIGHT...VSBYS SHOULD DROP TO MVFR AND POTENTIALLY LOWER EITHER
BRIEFLY OR IN ISOLATED LOCATIONS...WITH CIGS DROPPING TO IFR. SLOW
IMPROVING TREND ON SATURDAY WITH MVFR CIGS THROUGH THE
PERIOD...THOUGH KCLT MAY BEGIN TO SEE SOME SCATTERING TOWARD THE END
OF THE PERIOD. SW WINDS TO START WITH WEDGE CONTINUING TO ERODE...
AND WINDS SHIFTING NNE AND NE SATURDAY IN THE WAKE OF THE UPPER WAVE
AS A SURFACE HIGH PRESSURE AXIS PUSHES EAST OVER THE OHIO RIVER
VALLEY.
ELSEWHERE...AT KGSP/KGMU/KAND EXPECT AN OVERALL SIMILAR TREND TO
KCLT BUT WITH -SHRA IN AT TAF INITIALIZATION AND CIGS DROPPING A
LITTLE FASTER OVERNIGHT. KAVL/KHKY WILL SEE FEWER RESTRICTIONS BEING
A LITTLE FARTHER NORTH FROM THE DEEP MOISTURE...AND IT IS POSSIBLE
THAT KHKY MAY KEEP VFR CIGS THROUGH THE NIGHT THOUGH HAVE CONTINUED
MVFR TREND WITH THIS ISSUANCE. MVFR VSBYS STILL LIKELY WITH SURFACE
WINDS DROPPING OFF. ANY -TSRA TOO ISOLATED TO INCLUDE IN THE TAF AT
THIS TIME.
OUTLOOK...DRIER WEATHER IS FAVORED SATURDAY AFTERNOON. DEEPER
MOISTURE WILL RETURN ALONG A WARM FRONT SAT NIGHT THROUGH
SUNDAY...WITH HEAVY RAINFALL AND WIDESPREAD RESTRICTIONS LIKELY ONCE
AGAIN. THUNDERSTORMS WILL THEN BE POSSIBLE THROUGH MONDAY AS A COLD
FRONT REACHES THE AREA FROM THE WEST.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT MED 69% MED 69% LOW 57% HIGH 100%
KGSP MED 66% MED 62% LOW 51% HIGH 100%
KAVL HIGH 92% HIGH 87% LOW 59% HIGH 97%
KHKY HIGH 90% HIGH 98% MED 70% HIGH 100%
KGMU MED 64% LOW 58% LOW 47% HIGH 100%
KAND MED 61% MED 65% LOW 47% HIGH 87%
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...CSH
NEAR TERM...CDG/TDP
SHORT TERM...LG
LONG TERM...NED
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
747 PM EDT FRI APR 17 2015
.SYNOPSIS...
DRIER AND WARMER AIR WILL SPREAD INTO THE REGION THROUGH SATURDAY. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT INTO
SUNDAY...ACCOMPANIED BY ABUNDANT MOISTURE AND MORE RAINFALL. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...USHERING IN SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 730 PM EDT FRIDAY...HAVE BUMPED UP POPS ACROSS MOST OF THE
AREA THIS EVENING INTO THE OVERNIGHT PERIOD TO ACCOUNT FOR FAIRLY
WIDESPREAD LIGHT RAIN/SHOWERS MOVING ACROSS THE AREA...FORCED BY THE
RELATIVELY STRONG SHORTWAVE MOVING ACROSS THE SOUTHEAST THIS
EVENING. IF THE HRRR IS TO BE BELIEVED...THESE SHOWERS COULD LINGER
OVERNIGHT AND PAST SUNRISE...AND WILL EVALUATE FURTHER FOR THE LATE
EVENING UPDATE. BEST MOISTURE REMAINS ACROSS THE UPSTATE AND
NORTHEAST GEORGIA BUT STILL SEEING SOME LIGHT RAIN ACROSS THE
MOUNTAINS AND FOOTHILLS. STILL SEEING SOME SBCAPE VALUES HOLDING ON
ACROSS THE PIEDMONT BUT THESE SHOULD BEGIN DROPPING RAPIDLY WITH
SUNSET...SO HAVE PULLED BACK ON THUNDER WORDING THIS EVENING AND
OVERNIGHT. OTHER GRIDS IN GOOD SHAPE FOR THE MOST PART...WITH ONLY
MINOR TWEAKS TO ACCOUNT FOR HOURLY TRENDS.
AS OF 430 PM EDT FRIDAY...VERY LITTLE CHANGE TO PREVIOUS THINKING
FOR THE NEAR TERM. PRECIPITATION BEGINNING TO OVERSPREAD WESTERN AND
SOUTHWESTERN ZONES AS EXPECTED. NEW GUIDANCE BEGINNING TO PULL BACK
A LITTLE ON CONVECTIVE POTENTIAL...WITH INCREASING CLOUD COVER AND
MOISTENING ATMOSPHERE WHAT LITTLE SBCAPE WAS BEGINNING TO CREEP INTO
THE MESOANALYSES OVER THE PAST COUPLE OF HOURS IS ONCE AGAIN FALLING
OFF. LOOKING AT HI-RES REFLECTIVITY FORECASTS...DEFINITELY STARTING
TO LOOK LIKE MORE STRATIFORM RAIN OR SHOWERS WITH THE POSSIBILITY OF
EMBEDDED THUNDER. HAVE LEFT WEATHER WORDING AS IS FOR NOW SINCE
CURRENTLY ADVERTISED THUNDER IS CHANCE AT BEST...BUT WILL REEVALUATE
MORE THOROUGHLY FOR NEXT NEAR-TERM UPDATE. ONLY MINOR TWEAKS TO
TEMPS AND DEWPOINTS TO UPDATE TRENDS.
AS OF 245 PM EDT FRIDAY...THE SYNOPTIC PATTERN HAS NOT CHANGED ALL
THAT MUCH FROM YESTERDAY...OR DAYS PAST FOR THAT MATTER. IT STILL
FEATURES ROTATING CLOSE UPPER LOW OVER THE FOUR CORNERS WHILE DEEP
SOUTHWEST WAA PREVAILS ACROSS THE SOUTHEAST UNITED STATES. AT
THE SURFACE...SPRINGTIME WEDGE STARTING TO ERODE AS EXPECTED THIS
AFTERNOON AS WINDS HAVE VEERED SOUTHERLY ACROSS NORTHEAST GA AND THE
UPSTATE...ALONG WITH A FEW LOCATIONS OVER THE NC PIEDMONT.
FURTHERMORE...H5 SHORT WAVE AND ASSOCIATED VORTICITY MAXIMA
CONTINUES TO SLIDE EAST ACROSS THE DEEP SOUTH WITH A BROAD AREA OF
PRECIPITATION ACCOMPANYING. LATEST SPC MESO ANALYSIS NOT ALL THAT
IMPRESSIVE AS INSTABILITY REMAINS NEARLY NONEXISTENT ACROSS THE FCST
AREA. MODELS FAVOR IMPROVING LAPSE RATES WITH HEATING THIS
AFTERNOON...HOWEVER STILL SKEPTICAL AS PRECIP SHIELD AND ASSOCIATED
LOW OVERCAST SKY COVER WILL LIMIT HEATING. NEVERTHELESS...THE FCST
DOES FEATURE INCREASING POPS THROUGH THE AFTERNOON/EVENING HOURS
WITH CHANCES FOR THUNDER MENTIONED...AND WILL CONTINUE WITH SUCH IN
THE HWO. POPS WILL LOWER AFTER MIDNIGHT AS THE PRIMARY UPPER WAVE
EJECTS TO THE EAST...AND A WEAK/DRY BACK DOOR FRONT SLIDES SOUTHWARD
ACROSS THE REGION. HELD ON TO TOKEN SLIGHT/CHANCE POPS THROUGH
MORNING TO ACCOUNT FOR ANY RESIDUAL SHRA ALONG THE BOUNDARY. LATEST
SOUNDINGS DO NOT SUGGEST AS MUCH MID DRYING AS THE PREVIOUS
RUN...THEREFORE NOT ALL THAT CONFIDENT IN AREAS OF DENSE FOG
OVERNIGHT. THAT SAID...WOULDNT BE SURPRISED TO SEE ISOLATED CASES OF
SUCH ACROSS THE NC PIEDMONT/FOOTHILLS JUST AHEAD OF THE INTRUDING
BOUNDARY WHEN WINDS ARE CALMEST AND THE PBL IS DECOUPLED.
SATURDAY WILL BE HIGHLIGHTED BY DECREASING CLOUDINESS AS DOWNSLOPING
FLOW PREVAILS AMONGST INCREASING HEIGHTS ALOFT AS AXIS OF SHORTWAVE
RIDGE SHIFTS OVERHEAD. POPS WILL INCREASE YET AGAIN THROUGH THE DAY
AS FCST SOUNDINGS INDICATE MODEST DESTABILIZATION WITH HEATING.
HOWEVER EXPECTING UPPER RIDGING TO PROVIDE SOME SUBSIDENCE THEREFORE
KEPT POPS AT OR BELOW CHANCE LEVELS THROUGH THE DAY. TEMPERATURES
ON SATURDAY WILL DEPEND HIGHLY ON HOW SOON THE SKY COVER SCT OUT.
TOOK A MIDDLE OF THE ROAD APPROACH AS IT PERTAINS TO GUIDANCE...WITH
THE FCST FEATURING HIGHS 3-5 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRIDAY...TWO AREAS OF CONCERN TO DEAL WITH IN THE SHORT
TERM. THE FIRST WILL BE A PERIOD OF HEAVY RAIN ON SUNDAY AND THEN A
RISK OF SEVERE STORMS ON MONDAY.
THE UPPER RIDGE OVER THE SOUTHEAST U.S. WILL TRANSLATE EASTWARD
SATURDAY NIGHT AS THE UPPER LOW THAT HAS BEEN OVER THE 4-CORNERS
BEGINS TO MOVE EAST THANKS TO A DIGGING TROUGH MOVING SE OUT OF THE
CANADIAN PRAIRIE. A SHORT WAVE OUT AHEAD OF THE UPPER LOW WILL
MOVE NE FROM THE GULF COAST AND ACROSS THE WESTERN CAROLINAS AND
NE GA ON SUNDAY. AT THE SURFACE...A WARM FRONT WILL APPROACH FROM
THE SW ON SUNDAY. ALL OF THIS WILL RESULT IN ALL TYPES OF FORCING
ACROSS THE REGION ON SUNDAY. PWATS WILL BE IN THE 1.5-1.7" RANGE
WITH A 35-45 KT SELY 850 MB JET INTO THE BLUE RIDGE. WILL RAMP
POPS UP QUICKLY TO CATEGORICAL FROM WEST TO EAST BY MIDDAY
SUNDAY...THEN DECREASE RAPIDLY FROM WEST TO EAST LATE SUNDAY AS
THE AXIS OF DEEP MOISTURE AND FORCING SHIFT EAST. HEAVY RAIN LOOKS
TO BE A GOOD BET...BUT THE RELATIVELY QUICK MOVEMENT OF THE SYSTEM
SHOULD PRECLUDE ANY SERIOUS HYDRO ISSUES. BLENDING THE MODEL
CONSENSUS AND WPC QPF GUIDANCE... RESULTS IN GENERALLY 1.5"-2.0"
FROM LATE SATURDAY NIGHT INTO SUNDAY NIGHT. THE HIGHEST AMOUNTS AS
USUAL ARE EXPECTED TO BE NEAR THE BLUE RIDGE ESCARPMENT WHERE 2-3"
OF RAIN CAN BE EXPECTED. THESE VALUES ARE UNDER THE 12 TO 24 HOUR
FFG. THERE MAY BE SOME LOCALIZED FLOODING BUT WIDESPREAD FLOODING
IS UNLIKELY. HOWEVER...WILL CONTINUE TO MENTION HEAVY RAIN IN THE
HWO. AN IN SITU WEDGE WILL RESULT IN COOL TEMPS ON SUNDAY AND WILL
THEREFORE TREND TOWARD CONSRAW GUIDANCE TEMPS.
SOME DEGREE OF CLEARING SHOULD OCCUR SUNDAY NIGHT AS THE AXIS OF
DEEP MOISTURE SHIFTS NE AND A DOWNSLOPE WIND COMPONENT THROUGH THE
COLUMN DEVELOPS. ON MONDAY...A COLD FRONT WILL MOVE ACROSS THE
REGION FROM WEST TO EAST. BOTH THE NAM AND GFS INDICATE THAT THE
ATMOSPHERE WILL DESTABILIZE BY AFTERNOON WITH CAPES MOST LIKELY
INCREASING TO BETWEEN 1000 AND 1500 J/KG PER GFS AND ECM.
ALSO...0-6KM SHEAR INCREASES TO ABOUT 40KT. THIS MAY SUPPORT SOME
ORGANIZATION TO THE CONVECTION AS THE COLD FRONT MOVES THROUGH.
THE 12Z NAM MODEL REFLECTIVITY SUGGESTS THAT A BROKEN LINE OF
CONVECTION WILL ACCOMPANY THE FRONT ACROSS THE AREA ON MONDAY WITH
A FEW SEVERE STORMS POSSIBLE. WITH THE AREA SOLIDLY IN THE WARM
SECTOR ON MONDAY...MAX TEMPS ARE EXPECTED TO BE ABOUT 5 DEGREES
ABOVE CLIMO.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM FRIDAY...MONDAY NIGHT...SFC HIGH PRESSURE WILL BUILD
OVER THE FORECAST AREA IN THE WAKE OF A PASSING COLD FRONT. 12Z GFS
INDICATES THAT H85 TEMPERATURES WILL COOL BY 5 C FROM 0Z TO 12Z
TUESDAY...A LITTLE LESS COOLING ON THE ECMWF. USING A BLEND OF
GUIDANCE...I WILL FORECAST LOW TEMPERATURES FROM THE UPPER 40S
WITHIN THE MTN VALLEYS TO MID 50S EAST. ON TUESDAY...BROAD HIGH
PRESSURE WILL REMAIN ACROSS THE CWA. THE REGION SHOULD SEE MOSTLY
SUNNY CONDITIONS WITH A LIGHT SOUTHWEST WIND. TEMPERATURES SHOULD
RESPOND TO THE LATE APRIL SUN AND WEAK DOWNSLOPING...FORECAST TUES
HIGHS SLIGHTLY ABOVE NORMAL.
WEDNESDAY THROUGH FRIDAY...THE GFS AND ECMWF GENERALLY AGREE THAT A
LARGE CLOSED MID LEVEL LOW WILL REMAIN ACROSS THE NORTHEAST AND
EASTERN CANADA...AS A RIDGE LINGERS OVER THE SOUTHERN PLAINS. THE
HEIGHTS ACROSS THE CWA WILL LIKELY REMAIN NW TO SE THROUGH THE
PERIOD. THE MODELS ARE IN LESS AGREEMENT WITH THE PLACEMENT AND
TIMING OF SFC FEATURES...PRIMARILY WEAK FRONTS AND PRESSURE CENTERS.
I AM MORE CONFIDENT TIMING MID LEVEL FEATURES WITHIN THE NW FLOW
ACROSS THE SOUTHERN APPALACHIANS...I WILL FAVOR THE ECMWF.
OVERALL...I WILL KEEP CONDITIONS DRY ON WED...BUT MOISTURE WILL
INCREASE THROUGH THE DAY. A SHORT SERIES OF MID LEVEL S/W ARE
FORECAST TO RIPPLE ACROSS THE CWA THURSDAY THROUGH FRIDAY.
TEMPERATURES SHOULD RANGE CLOSE TO NORMAL WITH AFTERNOON DEWPOINTS
ONLY IN THE 40S. GIVEN THE TRACK OF THE MID LEVEL DISTURBANCES AND
WEAK DIURNAL INSTABILITY...I WILL INDICATE ONLY SCHC POPS ACROSS THE
MTNS ON THURSDAY. FORECAST SOUNDINGS SHOW GREATER INSTABILITY FRIDAY
AFTERNOON...FROM THE MTNS TO THE PIEDMONT. THE COMBINATION OF THE
PASSING DISTURBANCE AND INSTABILITY SHOULD SUPPORT SCT COVERAGE
ACROSS THE MTNS AND ISO EAST.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...EXPECT -SHRA TO SLOWLY SPREAD TOWARD THE AIRPORT AS
ANOTHER UPPER WAVE PUSHES ACROSS THE REGION. VFR CONDITIONS STILL
HANGING ON IN THE MEANTIME...BUT ONCE THE DEEPER MOISTURE ARRIVES...
CIGS SHOULD DROP TO MVFR IN THE NEXT COUPLE OF HOURS. AS WINDS
DECOUPLE OVERNIGHT...VSBYS SHOULD DROP TO MVFR AND POTENTIALLY LOWER
EITHER BRIEFLY OR IN ISOLATED LOCATIONS...WITH CIGS DROPPING TO IFR.
SLOW IMPROVING TREND ON SATURDAY WITH MVFR CIGS THROUGH THE
PERIOD...THOUGH KCLT MAY BEGIN TO SEE SOME SCATTERING TOWARD THE END
OF THE PERIOD. SW WINDS TO START WITH WEDGE CONTINUING TO ERODE...
AND WINDS SHIFTING NNE AND NE SATURDAY IN THE WAKE OF THE UPPER WAVE
AS A SURFACE HIGH PRESSURE AXIS PUSHES EAST OVER THE OHIO RIVER
VALLEY.
ELSEWHERE...AT KGSP/KGMU/KAND EXPECT AN OVERALL SIMILAR TREND TO
KCLT BUT WITH -SHRA IN AT TAF INITIALIZATION AND CIGS DROPPING A
LITTLE FASTER OVERNIGHT. KAVL/KHKY WILL SEE FEWER RESTRICTIONS BEING
A LITTLE FARTHER NORTH FROM THE DEEP MOISTURE...AND IT IS POSSIBLE
THAT KHKY MAY KEEP VFR CIGS THROUGH THE NIGHT THOUGH HAVE CONTINUED
MVFR TREND WITH THIS ISSUANCE. MVFR VSBYS STILL LIKELY WITH SURFACE
WINDS DROPPING OFF. ANY -TSRA TOO ISOLATED TO INCLUDE IN THE TAF AT
THIS TIME.
OUTLOOK...DRIER WEATHER IS FAVORED SATURDAY AFTERNOON. DEEPER
MOISTURE WILL RETURN ALONG A WARM FRONT SAT NIGHT THROUGH
SUNDAY...WITH HEAVY RAINFALL AND WIDESPREAD RESTRICTIONS LIKELY ONCE
AGAIN. THUNDERSTORMS WILL THEN BE POSSIBLE THROUGH MONDAY AS A COLD
FRONT REACHES THE AREA FROM THE WEST.
CONFIDENCE TABLE...
23-05Z 05-11Z 11-17Z 17-18Z
KCLT MED 64% MED 62% MED 64% HIGH 80%
KGSP MED 71% MED 69% LOW 46% HIGH 90%
KAVL HIGH 93% MED 62% MED 60% HIGH 100%
KHKY LOW 57% HIGH 100% MED 64% HIGH 100%
KGMU MED 78% MED 69% MED 64% HIGH 90%
KAND LOW 57% MED 69% MED 78% HIGH 80%
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...CSH
NEAR TERM...CDG/TDP
SHORT TERM...LG
LONG TERM...NED
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
626 PM CDT FRI APR 17 2015
.AVIATION...
LOW STRATUS WAS BREAKING UP NEAR KCDS EARLY THIS EVENING.
HOWEVER...THERE IS A CHANCE AT VLIFR CIGS AND VISBYS WILL RETURN
EARLY SATURDAY MORNING WITH VERY MOIST LOW LEVEL AIR STILL IN
PLACE. OTHERWISE...WINDS WILL COME AROUND TO THE WEST AT ALL TAF
SITES TOMORROW AFTERNOON AND BECOME BREEZY.
&&
.PREV DISCUSSION... /ISSUED 321 PM CDT FRI APR 17 2015/
SHORT TERM...
DRYLINE AT 19Z EXTENDED FROM JUST WEST OF SILVERTON SOUTH TO WHITE
RIVER LAKE AND NEAR LAKE ALAN HENRY. THIS BOUNDARY HAS BEEN FORCED
WEST ALL DAY BY CONVECTIVE OUTFLOWS FARTHER EAST AND RECENT RUNS OF
THE RUC HAVE THE DRYLINE ARRIVING ALONG INTERSTATE 27 BY THIS
EVENING...PERHAPS MUCH SOONER. INSTABILITY-WISE...A NARROW AXIS OF
SBCAPE AROUND 1000 J/KG MAY FULFILL SOME TSTORMS ALONG AND EAST OF
THE DRYLINE THROUGH THE EVENING...BUT VISUAL TRENDS OF TOWERING AND
MODERATE CU SUGGEST DEEPER ASCENT IS LACKING. WATER VAPOR IMAGERY
INDICATE THIS AREA IS BATTLING SUBSIDENCE ALOFT DUE TO AN AXIS OF
PERSISTENT DEEP CONVECTION 60-100 MILES FARTHER EAST. BECAUSE OF
THIS AND LIMITED NWP SUPPORT...POPS HAVE BEEN SCALED BACK TO SLIGHT
CHANCE FOR MOST AREAS OFF THE CAPROCK.
AS THE FOUR CORNERS LOW BEGINS LIFTING NORTHEAST TONIGHT...LOWER
TROPOSPHERIC WINDS WILL VEER MORE WESTERLY ACROSS THE WESTERN HALF
OF THE CWA AND HELP TO NUDGE THE DRYLINE EASTWARD BEFORE DAYBREAK
SAT. MODELS AGREE THE DRYLINE WILL MIX OUT OF OUR EASTERN ZONES BY
MIDDAY AHEAD OF BREEZY SW WINDS...BUT ANY DISRUPTION TO THIS SUCH AS
WE SAW TODAY WITH CONVECTIVE OUTFLOWS COULD SUPPORT A MORE WESTERLY
DRYLINE LOCATION AND NECESSITATE MODIFICATIONS TO OUR DRY FORECAST
FOR SATURDAY. WHEREVER THE DRYLINE ENDS UP...DEEP CONVECTION SHOULD
EASILY UNFOLD BY SAT AFTN UNDER WEAK INHIBITION...STRONGER CYCLONIC
FLOW AND A FAVORABLE MID-LEVEL COLD POCKET OF -20C AT 500MB.
LONG TERM...
COLD FRONT PROGGED TO MOVE THROUGH THE FCST AREA SUNDAY MORNING
WITH ENOUGH COLD ADVECTION TO RESULT IN HIGHS MAINLY UPPER 60S AND
LOWER 70S WHILE ALSO SCOURING LOW LEVEL MOISTURE OUT OF THE FCST
AREA. MAY SEE SOME CONVECTION ATTEMPT TO DEVELOP ON THE HIGH
TERRAIN OF NRN NM/SRN COLO AND BE DRIVEN TO THE SE ON NWLY UPPER
FLOW...BUT WITH DRY LOW LEVELS WOULD EXPECT IT TO HAVE A HARD
TIME GETTING THIS FAR TO THE SE. SITUATION CHANGES SOME MONDAY
WHEN SOUTH AND SE WINDS BEGIN TO BRING MOISTURE BACK INTO THE
AREA. LOOKS LIKE HIGH TERRAIN CONVECTION WILL HAVE A BETTER CHANCE
OF MOVING THROUGH THE PANHANDLE AND INTO NRN PARTS OF THE FCST
AREA.
THE MIDDLE PART OF THE WEEK WILL THEN BE ONE WITH POSSIBILITY OF
WEAKLY-FORCED DIURNAL DRYLINE STORMS WITH LOW LEVEL MOISTURE
INCREASING WITH TIME...CONFLUENT FLOW ALOFT TRANSITIONING TO WEAK
UPPER RIDGING. 20-30 PCT STORM CHANCES TUESDAY THROUGH FRIDAY LOOK
FINE WITH THIS SYNOPTIC SETUP.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 40 70 40 65 / 0 0 10 0
TULIA 43 73 44 67 / 0 0 10 0
PLAINVIEW 44 73 45 68 / 0 0 0 0
LEVELLAND 43 75 46 70 / 0 0 0 0
LUBBOCK 45 76 47 71 / 0 0 0 0
DENVER CITY 44 74 47 71 / 0 0 0 0
BROWNFIELD 45 76 48 72 / 0 0 0 0
CHILDRESS 55 79 51 73 / 20 10 10 0
SPUR 53 79 50 73 / 20 0 0 0
ASPERMONT 56 81 52 77 / 20 10 10 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1012 PM EDT FRI APR 17 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT AND SATURDAY BRINGING
DRY AND WARM WEATHER FOR THE START OF THE WEEKEND. A COMPLEX STORM
SYSTEM PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN
SUNDAY INTO SUNDAY NIGHT BEFORE A COLD FRONT CROSSES THE REGION WITH
A CHANCE OF SHOWERS AND POTENTIALLY STRONG STORMS ON MONDAY. DRY AND
COOL CONDITIONS WILL PREVAIL FOR THE MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1012 PM EDT FRIDAY...
ISOLD SHOWERS HAVE DISSIPATED AND SEE NO REASON FOR ANY NEW ONES
TO FIRE UP OVERNIGHT...OTHER THAN ONE OR TWO ACROSS NORTHERN NC
GIVEN MUCAPE VALUES STILL AROUND 300-500 J/KG. ALSO KEEPING AN EYE
ON THE NORTHERN EDGE OF AREA OF SHOWERS INTO SW NC...WHICH IS
AHEAD OF A SHORT WAVE NEAR CHATTANOOGA...AS SOMETHING COULD SNEAK
INTO OUR NW NC MTNS AFTER MIDNIGHT...BUT MOST GUIDANCE AGREES
THIS WILL STAY JUST TO OUR SOUTH. LEFT SLIGHT CHC POP ACROSS
SOUTHERN EDGE OF FCST AREA THROUGH MUCH OF THE NIGHT...BUT REMOVED
MENTION EVERYWHERE ELSE. TRENDS LOOK BETTER FOR MORE CLEARING FROM
WEST LATE...AND THUS POSSIBILITY OF SOME PATCHY VALLEY FOG WITH
WET GROUND SO ADDED THAT AS WELL...MAINLY TO MTN VALLEYS.
OVERNIGHT TEMPS LOOK ON TRACK AT THIS POINT.
PREV DISC AS OF 635 PM EDT FRIDAY...
UPDATE TO REFLECT CURRENT MAINLY ISOLD COVERAGE OF
SHOWERS FROM FOOTHILLS INTO SOUTHSIDE VA. INCLUDED A COUPLE HOURS
OF CHC POPS ACROSS SOUTHSIDE THROUGH EARLY EVENING WITH CLUSTER
OF SHOWERS THERE...AND SO FAR NOT SEEING ANY SIGNS OF EVEN
INTERCLOUD LIGHTNING WITH CELLS NEAR MTV AND DAN...BUT KEEPING
ISOLD THUNDER IN FCST GIVEN SBCAPES OF 500-800 J/KG....AND SOME
ISOL LTG IN CELLS JUST NORTHEAST OF BUCKINGHAM COUNTY. ALL THIS
ACTIVITY SHOULD SLOWLY DIMINISH AS IT DRIFTS SOUTHEASTWARD INTO
FAR NORTHERN NC BY 8 OR 9PM...AND RECENT HRRR RUNS SEEM TO BE
DOING A BETTER JOB CAPTURING THE SPARSITY OF THE SHALLOW
CONVECTION AND WEAKENING INTO THE EVENING HOURS WITH LOSS OF
HEATING.
SOME OF THE MORE WIDESPREAD LIGHT RAIN OVER FAR SW NC AND UPSTATE
SC WILL SLIDE TO THE NORTHEAST IN ADVANCE OF WEAK SHORT WAVE
HEADING EAST OUT OF TN...BUT PREVIOUS THINKING THAT IT WILL REMAIN
SOUTH OF THE FCST AREA STILL LOOKS ON TRACK. WE DO KEEP A
LINGERING SLIGHT CHC POP ACROSS NW NC MTNS UNTIL A LITTLE AFTER
MIDNIGHT JUST IN CASE...BUT THEN DROP ALL POPS TOWARD MORNING.
PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY...
AT 18Z...A WEAK SURFACE TROF WAS NOTED JUST EAST OF THE BLUE
RIDGE...AND WEAK CONVERGENCE ALONG THIS BOUNDARY COMBINED WITH SOME
MODEST INSTABILITY (DCAPES 500-700 J/KG) SHOULD GENERATE ISOLATED
SHOWERS AND STORMS ALONG THE BLUE RIDGE AS WELL AS AREAS NORTH OF I-
64 WHERE VISIBLE SATELLITE SHOWS SOME ENHANCED CUMULUS FORMING IN
ADVANCE OF A FAINT UPPER LEVEL DISTURBANCE.
MESOSCALE MODELS ARE OVERDONE ON THIS COVERAGE OF THIS PRECIP...BUT
GENERALLY HAVE A GOOD HANDLE ON THE LOCATION OF DEVELOPMENT.
ANY ISOLATED/WIDELY SCATTERED PRECIP THAT DEVELOPS SHOULD GRADUALLY
DIMINISH TONIGHT...BEFORE AN UPPER LEVEL SHORTWAVE IN WEST TENNESSEE
ZIPS ACROSS NRN NC LATE TONIGHT. THIS SYSTEM WILL BRING AN INCREASE
IN CLOUD COVER...ESPECIALLY ACROSS THE SOUTHERN PORTION OF OUR
FORECAST AREA LATE TONIGHT...AND A FEW SHOWERS MAY BE POSSIBLE.
AT THE SFC...HIGH PRESSURE WILL SLOWLY NOSE SOUTH INTO THE EASTERN
OHIO VALLEY BRINGING A LIGHT NORTH WIND. A SHALLOW LAYER OF MOISTURE
NEAR THE SURFACE WILL REMAIN...WHICH WILL RESULT IN POCKETS OF
FOG...ESPECIALLY WHERE CLOUDS ARE ABSENT TO THE NORTH. LEANED TOWARD
THE WARMER GUIDANCE VALUES WITH CLOUDS.
FOR SATURDAY...HEIGHTS BUILD IN ADVANCE OF A DEEP UPPER LEVEL TROF
IN THE WEST AND TEMPS SHOULD AGAIN WARM WELL INTO THE 70S AND THE
80S IN THE EAST.
A WEAK LOW LEVEL EAST FLOW COMBINED WITH A NOSE OF HIGHER THETA-E
AIR IN NW NC INTO FAR SW VA MAY SPARK ISOLATED SHOWERS/STORMS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 330 PM EDT FRIDAY...
FOCUS THROUGH THIS PERIOD REMAINS ON A STRONG NEGATIVELY TILTED
UPPER TROUGH PROGGED TO LIFT RAPIDLY NORTHEAST ACROSS THE REGION
SUNDAY INTO EARLY MONDAY. MEANWHILE...ANTECEDENT HIGH PRESSURE
WILL MOVE OFF THE MID-ATLANTIC COAST INTO A NEAR CLASSIC WEDGE
POSITION. STRONG PVA/ISENTROPIC LIFT INDUCED RAINFALL INTO THE
WEDGE AIR MASS WILL ENHANCE/INTENSIFY THE WEDGE SUNDAY.
RAINFALL/QPF WILL BE THE MAIN CONCERN AS THE WEDGE KEEPS A VERY
STABLE/COOL AIR MASS IS PLACE. MOIST SOUTHEAST...UPSLOPE FLOW
ALONG THE BLUE RIDGE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS
WATAUGA NORTHEAST TOWARD FLOYD. AS NOTED YESTERDAY...HOWEVER...THE
SYSTEM WILL REMAIN HIGHLY PROGRESSIVE...LIMITING THE PERIOD OF
HEAVIER RAINFALL TO 12 HOURS OR LESS. WPC HAS PARTS OF THE NC/VA
SOUTHERN VA PIEDMONT OUTLOOKED FOR EXCESSIVE RAINFALL. THE MAIN
CONCERN WITHIN THIS AREA WOULD BE WATAUGA THROUGH
ASHE/WILKES...WITH LESS CONCERN TOWARD THE DANVILLE AREA WHERE
ANTECEDENT CONDITIONS ARE RELATIVELY DRY. IN ADDITION...THE
CONVECTIVE THREAT THROUGH THE HEAVIER RAIN PERIOD AS NOTED ABOVE
IS MINIMAL TO NONE...WHICH SHOULD FURTHER REDUCE THE FLASH FLOOD
THREAT. WILL RE-EVALUATE AGAIN TOMORROW...BUT AT THIS POINT NO
NEED FOR A FLOOD/FLASH FLOOD WATCH. ONE MAY EVENTUALLY BE NEEDED
FOR A SMALL AREA INCLUDING THE NW NC MOUNTAINS AND THE ADJACENT
FOOTHILLS. WENT WELL BELOW GUIDANCE ON MAX TEMPS IN THE WEDGE
SUNDAY...BUT AT OR ABOVE GUIDANCE ON MONDAY IN THE WARM SECTOR.
MAX TEMPS MONDAY WILL BE A GOOD 20 DEGREES WARMER IN MOST AREAS
THAN ON SUNDAY.
MONDAY IS A DIFFERENT STORY. A SIGNIFICANT WARM SECTOR WILL SURGE
NORTHWARD INTO THE REGION MONDAY AFTERNOON BEHIND THE DEPARTING
UPPER TROUGH AND AN APPROACHING STRONG COLD FRONT ASSOCIATED WITH
A DEEPENING BROAD UPPER TROUGH ACROSS THE GREAT LAKES. SEVERAL OF
THE MODELS CONTINUE TO ADVERTISE GOOD POTENTIAL FOR STRONG
THUNDERSTORMS MONDAY AFTERNOON...WITH SIGNIFICANT SVR PARAMETER
NEAR 20000 ACROSS THE PIEDMONT...CAPES NEARING 2000 J/KG WITH AT
LEAST 20-30KTS OF 0-2KM LOW-LEVEL SHEAR AND LIS NEAR -4C. SPC DAY
4 OUTLOOK SUGGESTS THAT DAMAGING WINDS WOULD BE THE MAIN CONCERN
WITH ANY CONVECTION...MOST LIKELY LINEAR ORIENTED...THAT DEVELOPS
ALONG/IN ADVANCE OF THE COLD FRONT MONDAY AFTERNOON/EVENING. THIS
ACTIVITY QUICKLY MOVES EAST OF THE REGION MON AFTERNOON.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 345 PM EDT FRIDAY...
A TRANSITION TO A PATTERN MORE REMINISCENT OF WINTER CONTINUES TO
BE IN THE CARDS FOR THE EARLY AND MID PART OF NEXT WEEK AS A DEEP
AND BROAD UPPER TROUGH BUILDS INTO THE CENTRAL/EASTERN U.S. BY
TUESDAY...500MB HEIGHTS DROP INTO THE 560DM RANGE AND 850MB TEMPS
PLUNGE TOWARD THE 0C MARK ACROSS THE NORTH BY MIDWEEK.
ANTICYCLONIC FLOW...A SERIES OF EMBEDDED UPPER DISTURBANCES...AND
COLD ADVECTION WILL KEEP VARIABLE CLOUDINESS AND POTENTIALLY
UPSLOPE SHOWERS IN PLACE ACROSS THE MOUNTAINS. THE CLOUDS AND
CYCLONIC FLOW WILL HOLD MAX TEMPS INTO THE 50S AND LOWER 60S ACROSS
THE MOUNTAINS THROUGH MUCH OF THE LATER HALF OF NEXT WEEK...WHILE
60S TO 70S PREVAIL TO THE EAST WITH DOWNSLOPE NORTHWEST FLOW AND
SIGNIFICANTLY GREATER AMOUNTS OF SUNSHINE. AT THIS POINT A
DISTURBANCE ON WED APPEARS TO BE THE MOST SIGNIFICANT IN
POTENTIALLY BRINGING SHOWERS EAST OF THE MOUNTAINS. HAVE NOT
INTRODUCED ANY THUNDER AT THIS POINT GIVEN THE LOW-LEVEL
COLD/STABLE AIR MASS.
BY MID-WEEK...THE GFS/ECMWF BEGIN TO DIVERGE ON THE OVERALL
PATTERN...WITH THE ECMWF KEEPING THE DEEP UPPER TROUGH IN PLACE
ACROSS THE NORTHEAST AND A STRONGER NW FLOW INTO OUR REGION AS
WELL...WHILE THE GFS DEPICTS THE UPPER TROUGH LIFTING FURTHER
NORTH AND PLACING A ZONAL FLOW WITH A BAROCLINIC ZONE STUCK ACROSS
OUR CWA. THIS RESULTS IN SIGNIFICANT DIFFERENCES BETWEEN
MOISTURE/POPS ACROSS OUR CWA BETWEEN THE TWO MODELS...WITH THE GFS
VERY WET AND THE ECMWF MUCH DRIER...KEEPING THE BAROCLINIC ZONE
MUCH FURTHER SOUTH. HAVE JUST ADVERTISED CHC POPS FOR NOW UNTIL A
BETTER HANDLE ON THIS PATTERN AND TIMING IS OBTAINED. TEMPERATURES
ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE MID PART OF THE
WEEK...GRADUALLY TRENDING CLOSER TO NORMAL BY THE END OF THE
PERIOD.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
AS OF 750 PM EDT FRIDAY...
ISOLD SHOWERS NOT EXPECTED TO IMPACT ANY AIRPORTS THIS
EVENING...AND FOR MOST OF THE OVERNIGHT EXPECTING VFR CONDITIONS
AND LIGHT TO CALM WINDS WITH HIGH PRESSURE IN CONTROL. SOME
MOISTURE OFF TO SOUTH SHOULD REMAIN THERE WITH WEAK SHORT WAVE
MOVING IN FROM THE WEST ACROSS TENNESSEE AND SHUNTING AN AREA OF
SHOWERS EASTWARD. THIS WAVE WILL ALSO EVENTUALLY TAKE MID TO HIGH CLOUDS
EAST AND WITH CLEARING THERE IS LIKELY TO BE SOME RADIATION FOG
FORMING...LOWERED CONDITIONS TO IFR AT BLF...LWB...BCB...AND LYH
BY 08-09Z...BUT MOST CONFIDENT IN IFR CONDITIONS AT LWB AND BCB.
ANY FOG AND LOW STRATUS DISSIPATES BY 13Z OR SO...FOR WIDESPREAD
VFR CONDITIONS FOR THE DAY SATURDAY...WITH LIGHT EAST TO NORTHEAST
WINDS AS SFC HIGH PRESSURE REMAINS TO THE NORTH AND WEAK SFC
TROUGH WILL LINGER ACROSS NORTH CAROLINA. THIS MAY RESULT IN
ENOUGH WEAK CONVERGENCE AND UPSLOPE TO KICK OFF A FEW ISOLD SHWRS
OR TSTORMS BY AFTERNOON...ESPECIALLY NEAR BLUE RIDGE ALONG OR
SOUTH OF VA/NC BORDER...BUT VERY UNLIKELY ANY ONE SHOWER OR STORM
WILL IMPACT ANY AIRPORTS.
EXTENDED AVIATION...
A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION LATER IN
THE WEEKEND WITH A WARM FRONT BRINGING WIDESPREAD MVFR/IFR
CONDITIONS IN RAIN DURING THE DAY SUNDAY INTO SUNDAY NIGHT...
FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE MONDAY. THIS LIKELY TO
KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS THE
REGION LATER MONDAY. VFR RETURNS LATER MONDAY NIGHT AND TUESDAY
WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH GOOD DRYING
EXPECTED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...JH/PH/SK
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...JH/PH/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
753 PM EDT FRI APR 17 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT AND SATURDAY BRINGING
DRY AND WARM WEATHER FOR THE START OF THE WEEKEND. A COMPLEX STORM
SYSTEM PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN
SUNDAY INTO SUNDAY NIGHT BEFORE A COLD FRONT CROSSES THE REGION WITH
A CHANCE OF SHOWERS AND POTENTIALLY STRONG STORMS ON MONDAY. DRY AND
COOL CONDITIONS WILL PREVAIL FOR THE MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 635 PM EDT FRIDAY...
UPDATE TO REFLECT CURRENT MAINLY ISOLD COVERAGE OF
SHOWERS FROM FOOTHILLS INTO SOUTHSIDE VA. INCLUDED A COUPLE HOURS
OF CHC POPS ACROSS SOUTHSIDE THROUGH EARLY EVENING WITH CLUSTER
OF SHOWERS THERE...AND SO FAR NOT SEEING ANY SIGNS OF EVEN
INTERCLOUD LIGHTNING WITH CELLS NEAR MTV AND DAN...BUT KEEPING
ISOLD THUNDER IN FCST GIVEN SBCAPES OF 500-800 J/KG....AND SOME
ISOL LTG IN CELLS JUST NORTHEAST OF BUCKINGHAM COUNTY. ALL THIS
ACTIVITY SHOULD SLOWLY DIMINISH AS IT DRIFTS SOUTHEASTWARD INTO
FAR NORTHERN NC BY 8 OR 9PM...AND RECENT HRRR RUNS SEEM TO BE
DOING A BETTER JOB CAPTURING THE SPARSITY OF THE SHALLOW
CONVECTION AND WEAKENING INTO THE EVENING HOURS WITH LOSS OF
HEATING.
SOME OF THE MORE WIDESPREAD LIGHT RAIN OVER FAR SW NC AND UPSTATE
SC WILL SLIDE TO THE NORTHEAST IN ADVANCE OF WEAK SHORT WAVE
HEADING EAST OUT OF TN...BUT PREVIOUS THINKING THAT IT WILL REMAIN
SOUTH OF THE FCST AREA STILL LOOKS ON TRACK. WE DO KEEP A
LINGERING SLIGHT CHC POP ACROSS NW NC MTNS UNTIL A LITTLE AFTER
MIDNIGHT JUST IN CASE...BUT THEN DROP ALL POPS TOWARD MORNING.
PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY...
AT 18Z...A WEAK SURFACE TROF WAS NOTED JUST EAST OF THE BLUE
RIDGE...AND WEAK CONVERGENCE ALONG THIS BOUNDARY COMBINED WITH SOME
MODEST INSTABILITY (DCAPES 500-700 J/KG) SHOULD GENERATE ISOLATED
SHOWERS AND STORMS ALONG THE BLUE RIDGE AS WELL AS AREAS NORTH OF I-
64 WHERE VISIBLE SATELLITE SHOWS SOME ENHANCED CUMULUS FORMING IN
ADVANCE OF A FAINT UPPER LEVEL DISTURBANCE.
MESOSCALE MODELS ARE OVERDONE ON THIS COVERAGE OF THIS PRECIP...BUT
GENERALLY HAVE A GOOD HANDLE ON THE LOCATION OF DEVELOPMENT.
ANY ISOLATED/WIDELY SCATTERED PRECIP THAT DEVELOPS SHOULD GRADUALLY
DIMINISH TONIGHT...BEFORE AN UPPER LEVEL SHORTWAVE IN WEST TENNESSEE
ZIPS ACROSS NRN NC LATE TONIGHT. THIS SYSTEM WILL BRING AN INCREASE
IN CLOUD COVER...ESPECIALLY ACROSS THE SOUTHERN PORTION OF OUR
FORECAST AREA LATE TONIGHT...AND A FEW SHOWERS MAY BE POSSIBLE.
AT THE SFC...HIGH PRESSURE WILL SLOWLY NOSE SOUTH INTO THE EASTERN
OHIO VALLEY BRINGING A LIGHT NORTH WIND. A SHALLOW LAYER OF MOISTURE
NEAR THE SURFACE WILL REMAIN...WHICH WILL RESULT IN POCKETS OF
FOG...ESPECIALLY WHERE CLOUDS ARE ABSENT TO THE NORTH. LEANED TOWARD
THE WARMER GUIDANCE VALUES WITH CLOUDS.
FOR SATURDAY...HEIGHTS BUILD IN ADVANCE OF A DEEP UPPER LEVEL TROF
IN THE WEST AND TEMPS SHOULD AGAIN WARM WELL INTO THE 70S AND THE
80S IN THE EAST.
A WEAK LOW LEVEL EAST FLOW COMBINED WITH A NOSE OF HIGHER THETA-E
AIR IN NW NC INTO FAR SW VA MAY SPARK ISOLATED SHOWERS/STORMS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 330 PM EDT FRIDAY...
FOCUS THROUGH THIS PERIOD REMAINS ON A STRONG NEGATIVELY TILTED
UPPER TROUGH PROGGED TO LIFT RAPIDLY NORTHEAST ACROSS THE REGION
SUNDAY INTO EARLY MONDAY. MEANWHILE...ANTECEDENT HIGH PRESSURE
WILL MOVE OFF THE MID-ATLANTIC COAST INTO A NEAR CLASSIC WEDGE
POSITION. STRONG PVA/ISENTROPIC LIFT INDUCED RAINFALL INTO THE
WEDGE AIR MASS WILL ENHANCE/INTENSIFY THE WEDGE SUNDAY.
RAINFALL/QPF WILL BE THE MAIN CONCERN AS THE WEDGE KEEPS A VERY
STABLE/COOL AIR MASS IS PLACE. MOIST SOUTHEAST...UPSLOPE FLOW
ALONG THE BLUE RIDGE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS
WATAUGA NORTHEAST TOWARD FLOYD. AS NOTED YESTERDAY...HOWEVER...THE
SYSTEM WILL REMAIN HIGHLY PROGRESSIVE...LIMITING THE PERIOD OF
HEAVIER RAINFALL TO 12 HOURS OR LESS. WPC HAS PARTS OF THE NC/VA
SOUTHERN VA PIEDMONT OUTLOOKED FOR EXCESSIVE RAINFALL. THE MAIN
CONCERN WITHIN THIS AREA WOULD BE WATAUGA THROUGH
ASHE/WILKES...WITH LESS CONCERN TOWARD THE DANVILLE AREA WHERE
ANTECEDENT CONDITIONS ARE RELATIVELY DRY. IN ADDITION...THE
CONVECTIVE THREAT THROUGH THE HEAVIER RAIN PERIOD AS NOTED ABOVE
IS MINIMAL TO NONE...WHICH SHOULD FURTHER REDUCE THE FLASH FLOOD
THREAT. WILL RE-EVALUATE AGAIN TOMORROW...BUT AT THIS POINT NO
NEED FOR A FLOOD/FLASH FLOOD WATCH. ONE MAY EVENTUALLY BE NEEDED
FOR A SMALL AREA INCLUDING THE NW NC MOUNTAINS AND THE ADJACENT
FOOTHILLS. WENT WELL BELOW GUIDANCE ON MAX TEMPS IN THE WEDGE
SUNDAY...BUT AT OR ABOVE GUIDANCE ON MONDAY IN THE WARM SECTOR.
MAX TEMPS MONDAY WILL BE A GOOD 20 DEGREES WARMER IN MOST AREAS
THAN ON SUNDAY.
MONDAY IS A DIFFERENT STORY. A SIGNIFICANT WARM SECTOR WILL SURGE
NORTHWARD INTO THE REGION MONDAY AFTERNOON BEHIND THE DEPARTING
UPPER TROUGH AND AN APPROACHING STRONG COLD FRONT ASSOCIATED WITH
A DEEPENING BROAD UPPER TROUGH ACROSS THE GREAT LAKES. SEVERAL OF
THE MODELS CONTINUE TO ADVERTISE GOOD POTENTIAL FOR STRONG
THUNDERSTORMS MONDAY AFTERNOON...WITH SIGNIFICANT SVR PARAMETER
NEAR 20000 ACROSS THE PIEDMONT...CAPES NEARING 2000 J/KG WITH AT
LEAST 20-30KTS OF 0-2KM LOW-LEVEL SHEAR AND LIS NEAR -4C. SPC DAY
4 OUTLOOK SUGGESTS THAT DAMAGING WINDS WOULD BE THE MAIN CONCERN
WITH ANY CONVECTION...MOST LIKELY LINEAR ORIENTED...THAT DEVELOPS
ALONG/IN ADVANCE OF THE COLD FRONT MONDAY AFTERNOON/EVENING. THIS
ACTIVITY QUICKLY MOVES EAST OF THE REGION MON AFTERNOON.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 345 PM EDT FRIDAY...
A TRANSITION TO A PATTERN MORE REMINISCENT OF WINTER CONTINUES TO
BE IN THE CARDS FOR THE EARLY AND MID PART OF NEXT WEEK AS A DEEP
AND BROAD UPPER TROUGH BUILDS INTO THE CENTRAL/EASTERN U.S. BY
TUESDAY...500MB HEIGHTS DROP INTO THE 560DM RANGE AND 850MB TEMPS
PLUNGE TOWARD THE 0C MARK ACROSS THE NORTH BY MIDWEEK.
ANTICYCLONIC FLOW...A SERIES OF EMBEDDED UPPER DISTURBANCES...AND
COLD ADVECTION WILL KEEP VARIABLE CLOUDINESS AND POTENTIALLY
UPSLOPE SHOWERS IN PLACE ACROSS THE MOUNTAINS. THE CLOUDS AND
CYCLONIC FLOW WILL HOLD MAX TEMPS INTO THE 50S AND LOWER 60S ACROSS
THE MOUNTAINS THROUGH MUCH OF THE LATER HALF OF NEXT WEEK...WHILE
60S TO 70S PREVAIL TO THE EAST WITH DOWNSLOPE NORTHWEST FLOW AND
SIGNIFICANTLY GREATER AMOUNTS OF SUNSHINE. AT THIS POINT A
DISTURBANCE ON WED APPEARS TO BE THE MOST SIGNIFICANT IN
POTENTIALLY BRINGING SHOWERS EAST OF THE MOUNTAINS. HAVE NOT
INTRODUCED ANY THUNDER AT THIS POINT GIVEN THE LOW-LEVEL
COLD/STABLE AIR MASS.
BY MID-WEEK...THE GFS/ECMWF BEGIN TO DIVERGE ON THE OVERALL
PATTERN...WITH THE ECMWF KEEPING THE DEEP UPPER TROUGH IN PLACE
ACROSS THE NORTHEAST AND A STRONGER NW FLOW INTO OUR REGION AS
WELL...WHILE THE GFS DEPICTS THE UPPER TROUGH LIFTING FURTHER
NORTH AND PLACING A ZONAL FLOW WITH A BAROCLINIC ZONE STUCK ACROSS
OUR CWA. THIS RESULTS IN SIGNIFICANT DIFFERENCES BETWEEN
MOISTURE/POPS ACROSS OUR CWA BETWEEN THE TWO MODELS...WITH THE GFS
VERY WET AND THE ECMWF MUCH DRIER...KEEPING THE BAROCLINIC ZONE
MUCH FURTHER SOUTH. HAVE JUST ADVERTISED CHC POPS FOR NOW UNTIL A
BETTER HANDLE ON THIS PATTERN AND TIMING IS OBTAINED. TEMPERATURES
ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE MID PART OF THE
WEEK...GRADUALLY TRENDING CLOSER TO NORMAL BY THE END OF THE
PERIOD.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 750 PM EDT FRIDAY...
ISOLD SHOWERS NOT EXPECTED TO IMPACT ANY AIRPORTS THIS
EVENING...AND FOR MOST OF THE OVERNIGHT EXPECTING VFR CONDITIONS
AND LIGHT TO CALM WINDS WITH HIGH PRESSURE IN CONTROL. SOME
MOISTURE OFF TO SOUTH SHOULD REMAIN THERE WITH WEAK SHORT WAVE
MOVING IN FROM THE WEST ACROSS TENNESSEE AND SHUNTING AN AREA OF
SHOWERS EASTWARD. THIS WAVE WILL ALSO EVENTUALLY TAKE MID TO HIGH CLOUDS
EAST AND WITH CLEARING THERE IS LIKELY TO BE SOME RADIATION FOG
FORMING...LOWERED CONDITIONS TO IFR AT BLF...LWB...BCB...AND LYH
BY 08-09Z...BUT MOST CONFIDENT IN IFR CONDITIONS AT LWB AND BCB.
ANY FOG AND LOW STRATUS DISSIPATES BY 13Z OR SO...FOR WIDESPREAD
VFR CONDITIONS FOR THE DAY SATURDAY...WITH LIGHT EAST TO NORTHEAST
WINDS AS SFC HIGH PRESSURE REMAINS TO THE NORTH AND WEAK SFC
TROUGH WILL LINGER ACROSS NORTH CAROLINA. THIS MAY RESULT IN
ENOUGH WEAK CONVERGENCE AND UPSLOPE TO KICK OFF A FEW ISOLD SHWRS
OR TSTORMS BY AFTERNOON...ESPECIALLY NEAR BLUE RIDGE ALONG OR
SOUTH OF VA/NC BORDER...BUT VERY UNLIKELY ANY ONE SHOWER OR STORM
WILL IMPACT ANY AIRPORTS.
EXTENDED AVIATION...
A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION LATER IN
THE WEEKEND WITH A WARM FRONT BRINGING WIDESPREAD MVFR/IFR
CONDITIONS IN RAIN DURING THE DAY SUNDAY INTO SUNDAY NIGHT...
FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE MONDAY. THIS LIKELY TO
KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS THE
REGION LATER MONDAY. VFR RETURNS LATER MONDAY NIGHT AND TUESDAY
WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT WITH GOOD DRYING
EXPECTED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...JH/PH/SK
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...JH/PH/SK
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1250 PM CDT THU APR 16 2015
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 257 AM CDT THU APR 16 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE CENTERED OVER THE EAST COAST...BUT WITH A RIDGE AXIS
EXTENDING WEST TO THE WESTERN GREAT LAKES. VERY DRY AIR CONTINUES TO
HOLD ON ACROSS THE REGION...AND DEWPOINTS HAVE STRUGGLED TO RECOVER
OVER CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. SOUTHEAST LOW
LEVEL FLOW OVER THE SOUTHERN GREAT LAKES IS SLOWLY VEERING TO MORE
OF A SOUTHERLY DIRECTION...BUT IS STILL TRYING TO PUSH LIGHT SHOWER
ACTIVITY ACROSS SOUTH-CENTRAL LAKE MICHIGAN. THIS IS AHEAD OF A
SHORTWAVE OVER THE IL/IN BORDER. THE BONE DRY AIRMASS AND VEERING
FLOW IS NOT HELPING THESE SHOWERS TO MAKE A WESTWARD JAUNT...AND THE
LATEST MESOMODELS KEEP THESE SHOWERS EAST OF THE MANITOWOC SHORELINE
EARLY THIS MORNING. THIS SHOWER ACTIVITY ALONG WITH FIRE WEATHER
CONDITIONS ARE THE MAIN FORECAST CONCERNS IN THE SHORT TERM.
TODAY...THE SHORTWAVE OVER THE IL/IN BORDER WILL LIFT NE THIS
MORNING AND THEN EAST THIS AFTERNOON AS RIDGING OVER THE GREAT LAKES
FLATTENS. 850MB FLOW WILL CONTINUE TO VERY GRADUALLY VEER THIS
MORNING WHICH COMBINED WITH THE VERY DRY AIR ACROSS THE REGION WILL
GIVE THE LIGHT SHOWER ACTIVITY OVER SOUTHERN LAKE MICHIGAN A SUBTLE
PUSH TO THE EAST. SO WILL KEEP THE DRY FORECAST IN TACT...BUT WILL
INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN TODAY AS 5K-6KFT
CLOUDS OVER NORTHERN ILLINOIS WILL LIKELY ARRIVE THIS MORNING.
ELSEWHERE...A MID-LEVEL DECK OVER MINNESOTA AND IOWA WILL SHIFT TO
THE EAST AND MOVE INTO NORTH-CENTRAL WISCONSIN DURING THE
AFTERNOON. UNTIL THESE CLOUDS ARRIVE...A POCKET OF VERY DRY AIR
WILL REMAIN IN PLACE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN.
MIXING WILL NOT BE AS GOOD TODAY DUE TO LIGHTER WINDS ALOFT...BUT
STILL LOWERED DEWPOINTS SINCE THINK WILL STILL BE ABLE TO TAP INTO
SOME OF THE BONE DRY AIR JUST ABOVE THE INVERSION. AS A
RESULT...HAVE DROPPED DEWPOINTS AND HUMIDITIES OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THIS AFTERNOON. HUMIDITIES COULD FALL
BETWEEN 20-25 PCT. FORTUNATELY...WINDS WILL BE MUCH LIGHTER
TODAY...SO SHOULD NOT SEE A REPEAT OF THE CRITICAL FIRE WEATHER
CONDITIONS. HIGHS MAINLY IN THE MID TO UPPER 60S AWAY FROM LAKE
MICHIGAN.
TONIGHT...A COLD FRONT WILL DECAY AS IT MOVES INTO NORTH-CENTRAL
WISCONSIN LATE. MID-LEVEL CLOUDS WILL CONTINUE TO SPREAD EAST AHEAD
OF THE FRONT...BUT GRADUALLY DISSIPATE IN THE PROCESS. SHOULD
THEREFORE SEE A PARTLY CLOUDY TO MOSTLY CLEAR NIGHT. WITH THE
THINNING CLOUDS...DO NOT THINK THERE WILL BE A DEEP ENOUGH CLOUD
LAYER FOR SPRINKLES OR LIGHT SHOWERS. LOWS MAINLY IN THE LOW TO MID
40S.
FRIDAY...THE FRONT WILL WASH OUT ACROSS NORTHERN WISCONSIN. MAY SEE
SOME CU DEVELOP OVER CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE
AFTERNOON...BUT THE NORTH SHOULD SEE AN INFLUX OF DRY AIR...THAT
WILL DROP HUMIDITIES NEAR 25 PCT IN THE AFTERNOON. HIGHS WILL BE
WARMER THAN TODAYS READINGS...AND RAISED THEM INTO THE UPPER 60S
NORTH TO MID 70S SOUTH.
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 257 AM CDT THU APR 16 2015
DRY CONDITIONS WILL CONTINUE FRIDAY NIGHT AND SATURDAY AS CANADIAN
HIGH PRESSURE BUILDS INTO THE STATE. NORTHWEST WINDS WILL TURN
TO THE EAST AND NORTHEAST LATE FRIDAY NIGHT AND SATURDAY. SATURDAY
AFTERNOON WILL AGAIN FEATURE VERY LOW AFTERNOON RELATIVE HUMIDITY
READINGS AWAY FROM THE LAKE...WITH READINGS DROPPING INTO THE 20
TO 40 PERCENT RANGE WITH THE LOWEST READINGS NORTH AND WEST OF THE
FOX VALLEY.
MEANWHILE...CLOSED UPPER LOW ACROSS THE CENTRAL PLAINS IS EXPECTED
TO OPEN UP AS 500MB TROUGH ACROSS SOUTHERN CANADA WILL BEGIN TO
LIFT THE SOUTHERN SYSTEM NORTHEAST TOWARDS THE REGION. QUIET A
SPREAD IN THE MODELS ON HOW QUICK THE RAIN WILL ARRIVE OVER THE
WEEKEND. THE WRF MODELS WAS QUICKEST...ALREADY BRINGING RAIN ON
SATURDAY TO PORTIONS OF THE AREA. THE GFS MODEL WAS IN THE MIDDLE
OF THE ROAD SOLUTION...WHILE THE CANADIAN/ECMWF MODEL WERE THE SLOWEST
SOLUTION WITH RAIN ARRIVING ON SUNDAY. TRENDED TOWARD THE SLOWER
SOLUTION FOR THE MEANTIME DUE TO BETTER CONSISTENCY FROM RUN TO
RUN. DID ADD A SMALL CHANCE OF RAIN ACROSS THE WEST LATE SATURDAY
NIGHT...AND THEN BOOSTED RAIN CHANCES INTO THE LIKELY CATEGORY ON
SUNDAY. DID RAISE RAIN CHANCES SUNDAY NIGHT AS WELL. THE 500MB
SYSTEMS WILL MERGE INTO A CLOSED UPPER LOW ACROSS THE UPPER
MIDWEST AND WESTERN GREAT LAKES REGION EARLY NEXT WEEK. THIS
WOULD SUPPORT A COOLER AND UNSETTLED PATTERN ACROSS THE REGION
ON MONDAY THROUGH WEDNESDAY. HAVE CHANCES OF SHOWERS EACH PERIOD...
ALONG WITH A LITTLE SNOW LATE AT NIGHT INTO THE EARLY MORNING
HOURS ON TUESDAY AND WEDNESDAY. IT IS WISCONSIN! TEMPERATURES
BY EARLY NEXT WEEK WILL RUN WELL BELOW NORMAL.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1250 PM CDT THU APR 16 2015
VFR CONDITIONS SHOULD PREVAIL THROUGH AT LEAST FRIDAY MORNING.
A CLOUD DECK BELOW 1KFT MOVED INTO THE SOUTHEAST PART OF THE AREA
THIS MORNING BUT MOVED OVER LAKE MICHIGAN BY 17Z. RADAR SHOWED SOME
ECHOES ACROSS PARTS OF CENTRAL/NORTH CENTRAL WISCONSIN DRIFTING TO
THE EAST BUT THEY WERE SCATTERED...SURFACE DEW POINT DEPRESSIONS
WERE IN EXCESS OF 30F...AND MOST OF THE SURFACE OBSERVATIONS IN
THAT PART OF THE STATE DID NOT EVEN INDICATE ANY CLOUDS. MODEL
TIME SECTIONS SHOWED A MOIST LAYER OVERNIGHT IN THE 5KFT-10KFT
RANGE...WITH DECREASING RH IN THAT LAYER AROUND 12Z. THE SURFACE
PRESSURE GRADIENT IS NOT EXPECTED TO BE TIGHT...SO WINDS SHOULD
REMAIN LIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......MG
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
606 AM CDT THU APR 16 2015
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 257 AM CDT THU APR 16 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE CENTERED OVER THE EAST COAST...BUT WITH A RIDGE AXIS
EXTENDING WEST TO THE WESTERN GREAT LAKES. VERY DRY AIR CONTINUES TO
HOLD ON ACROSS THE REGION...AND DEWPOINTS HAVE STRUGGLED TO RECOVER
OVER CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. SOUTHEAST LOW
LEVEL FLOW OVER THE SOUTHERN GREAT LAKES IS SLOWLY VEERING TO MORE
OF A SOUTHERLY DIRECTION...BUT IS STILL TRYING TO PUSH LIGHT SHOWER
ACTIVITY ACROSS SOUTH-CENTRAL LAKE MICHIGAN. THIS IS AHEAD OF A
SHORTWAVE OVER THE IL/IN BORDER. THE BONE DRY AIRMASS AND VEERING
FLOW IS NOT HELPING THESE SHOWERS TO MAKE A WESTWARD JAUNT...AND THE
LATEST MESOMODELS KEEP THESE SHOWERS EAST OF THE MANITOWOC SHORELINE
EARLY THIS MORNING. THIS SHOWER ACTIVITY ALONG WITH FIRE WEATHER
CONDITIONS ARE THE MAIN FORECAST CONCERNS IN THE SHORT TERM.
TODAY...THE SHORTWAVE OVER THE IL/IN BORDER WILL LIFT NE THIS
MORNING AND THEN EAST THIS AFTERNOON AS RIDGING OVER THE GREAT LAKES
FLATTENS. 850MB FLOW WILL CONTINUE TO VERY GRADUALLY VEER THIS
MORNING WHICH COMBINED WITH THE VERY DRY AIR ACROSS THE REGION WILL
GIVE THE LIGHT SHOWER ACTIVITY OVER SOUTHERN LAKE MICHIGAN A SUBTLE
PUSH TO THE EAST. SO WILL KEEP THE DRY FORECAST IN TACT...BUT WILL
INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN TODAY AS 5K-6KFT
CLOUDS OVER NORTHERN ILLINOIS WILL LIKELY ARRIVE THIS MORNING.
ELSEWHERE...A MID-LEVEL DECK OVER MINNESOTA AND IOWA WILL SHIFT TO
THE EAST AND MOVE INTO NORTH-CENTRAL WISCONSIN DURING THE
AFTERNOON. UNTIL THESE CLOUDS ARRIVE...A POCKET OF VERY DRY AIR
WILL REMAIN IN PLACE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN.
MIXING WILL NOT BE AS GOOD TODAY DUE TO LIGHTER WINDS ALOFT...BUT
STILL LOWERED DEWPOINTS SINCE THINK WILL STILL BE ABLE TO TAP INTO
SOME OF THE BONE DRY AIR JUST ABOVE THE INVERSION. AS A
RESULT...HAVE DROPPED DEWPOINTS AND HUMIDITIES OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THIS AFTERNOON. HUMIDITIES COULD FALL
BETWEEN 20-25 PCT. FORTUNATELY...WINDS WILL BE MUCH LIGHTER
TODAY...SO SHOULD NOT SEE A REPEAT OF THE CRITICAL FIRE WEATHER
CONDITIONS. HIGHS MAINLY IN THE MID TO UPPER 60S AWAY FROM LAKE
MICHIGAN.
TONIGHT...A COLD FRONT WILL DECAY AS IT MOVES INTO NORTH-CENTRAL
WISCONSIN LATE. MID-LEVEL CLOUDS WILL CONTINUE TO SPREAD EAST AHEAD
OF THE FRONT...BUT GRADUALLY DISSIPATE IN THE PROCESS. SHOULD
THEREFORE SEE A PARTLY CLOUDY TO MOSTLY CLEAR NIGHT. WITH THE
THINNING CLOUDS...DO NOT THINK THERE WILL BE A DEEP ENOUGH CLOUD
LAYER FOR SPRINKLES OR LIGHT SHOWERS. LOWS MAINLY IN THE LOW TO MID
40S.
FRIDAY...THE FRONT WILL WASH OUT ACROSS NORTHERN WISCONSIN. MAY SEE
SOME CU DEVELOP OVER CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE
AFTERNOON...BUT THE NORTH SHOULD SEE AN INFLUX OF DRY AIR...THAT
WILL DROP HUMIDITIES NEAR 25 PCT IN THE AFTERNOON. HIGHS WILL BE
WARMER THAN TODAYS READINGS...AND RAISED THEM INTO THE UPPER 60S
NORTH TO MID 70S SOUTH.
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 257 AM CDT THU APR 16 2015
DRY CONDITIONS WILL CONTINUE FRIDAY NIGHT AND SATURDAY AS CANADIAN
HIGH PRESSURE BUILDS INTO THE STATE. NORTHWEST WINDS WILL TURN
TO THE EAST AND NORTHEAST LATE FRIDAY NIGHT AND SATURDAY. SATURDAY
AFTERNOON WILL AGAIN FEATURE VERY LOW AFTERNOON RELATIVE HUMIDITY
READINGS AWAY FROM THE LAKE...WITH READINGS DROPPING INTO THE 20
TO 40 PERCENT RANGE WITH THE LOWEST READINGS NORTH AND WEST OF THE
FOX VALLEY.
MEANWHILE...CLOSED UPPER LOW ACROSS THE CENTRAL PLAINS IS EXPECTED
TO OPEN UP AS 500MB TROUGH ACROSS SOUTHERN CANADA WILL BEGIN TO
LIFT THE SOUTHERN SYSTEM NORTHEAST TOWARDS THE REGION. QUIET A
SPREAD IN THE MODELS ON HOW QUICK THE RAIN WILL ARRIVE OVER THE
WEEKEND. THE WRF MODELS WAS QUICKEST...ALREADY BRINGING RAIN ON
SATURDAY TO PORTIONS OF THE AREA. THE GFS MODEL WAS IN THE MIDDLE
OF THE ROAD SOLUTION...WHILE THE CANADIAN/ECMWF MODEL WERE THE SLOWEST
SOLUTION WITH RAIN ARRIVING ON SUNDAY. TRENDED TOWARD THE SLOWER
SOLUTION FOR THE MEANTIME DUE TO BETTER CONSISTENCY FROM RUN TO
RUN. DID ADD A SMALL CHANCE OF RAIN ACROSS THE WEST LATE SATURDAY
NIGHT...AND THEN BOOSTED RAIN CHANCES INTO THE LIKELY CATEGORY ON
SUNDAY. DID RAISE RAIN CHANCES SUNDAY NIGHT AS WELL. THE 500MB
SYSTEMS WILL MERGE INTO A CLOSED UPPER LOW ACROSS THE UPPER
MIDWEST AND WESTERN GREAT LAKES REGION EARLY NEXT WEEK. THIS
WOULD SUPPORT A COOLER AND UNSETTLED PATTERN ACROSS THE REGION
ON MONDAY THROUGH WEDNESDAY. HAVE CHANCES OF SHOWERS EACH PERIOD...
ALONG WITH A LITTLE SNOW LATE AT NIGHT INTO THE EARLY MORNING
HOURS ON TUESDAY AND WEDNESDAY. IT IS WISCONSIN! TEMPERATURES
BY EARLY NEXT WEEK WILL RUN WELL BELOW NORMAL.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 605 AM CDT THU APR 16 2015
VFR CONDITIONS EXPECTED TODAY AND TONIGHT. SCATTERED LIGHT SHOWERS OVER
LAKE MICHIGAN WILL APPROACH MTW THIS MORNING...BUT GUIDANCE KEEPS
THIS SHOWER ACTIVITY JUST OFFSHORE. WILL CONTINUE TO MONITOR.
OTHERWISE...A BROKEN 6KFT CLOUD DECK WILL MOVE INTO EAST-CENTRAL
WISCONSIN THIS MORNING BEFORE DEPARTING EARLY IN THE AFTERNOON.
THEN SCT TO BKN MID CLOUDS WILL MOVE ACROSS THE REGION FROM WEST
TO EAST LATE THIS AFTERNOON INTO TONIGHT. NO PRECIPITATION IS
EXPECTED.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......MPC
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 257 AM CDT THU APR 16 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE CENTERED OVER THE EAST COAST...BUT WITH A RIDGE AXIS
EXTENDING WEST TO THE WESTERN GREAT LAKES. VERY DRY AIR CONTINUES TO
HOLD ON ACROSS THE REGION...AND DEWPOINTS HAVE STRUGGLED TO RECOVER
OVER CENTRAL AND NORTH-CENTRAL WISCONSIN OVERNIGHT. SOUTHEAST LOW
LEVEL FLOW OVER THE SOUTHERN GREAT LAKES IS SLOWLY VEERING TO MORE
OF A SOUTHERLY DIRECTION...BUT IS STILL TRYING TO PUSH LIGHT SHOWER
ACTIVITY ACROSS SOUTH-CENTRAL LAKE MICHIGAN. THIS IS AHEAD OF A
SHORTWAVE OVER THE IL/IN BORDER. THE BONE DRY AIRMASS AND VEERING
FLOW IS NOT HELPING THESE SHOWERS TO MAKE A WESTWARD JAUNT...AND THE
LATEST MESOMODELS KEEP THESE SHOWERS EAST OF THE MANITOWOC SHORELINE
EARLY THIS MORNING. THIS SHOWER ACTIVITY ALONG WITH FIRE WEATHER
CONDITIONS ARE THE MAIN FORECAST CONCERNS IN THE SHORT TERM.
TODAY...THE SHORTWAVE OVER THE IL/IN BORDER WILL LIFT NE THIS
MORNING AND THEN EAST THIS AFTERNOON AS RIDGING OVER THE GREAT LAKES
FLATTENS. 850MB FLOW WILL CONTINUE TO VERY GRADUALLY VEER THIS
MORNING WHICH COMBINED WITH THE VERY DRY AIR ACROSS THE REGION WILL
GIVE THE LIGHT SHOWER ACTIVITY OVER SOUTHERN LAKE MICHIGAN A SUBTLE
PUSH TO THE EAST. SO WILL KEEP THE DRY FORECAST IN TACT...BUT WILL
INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN TODAY AS 5K-6KFT
CLOUDS OVER NORTHERN ILLINOIS WILL LIKELY ARRIVE THIS MORNING.
ELSEWHERE...A MID-LEVEL DECK OVER MINNESOTA AND IOWA WILL SHIFT TO
THE EAST AND MOVE INTO NORTH-CENTRAL WISCONSIN DURING THE
AFTERNOON. UNTIL THESE CLOUDS ARRIVE...A POCKET OF VERY DRY AIR
WILL REMAIN IN PLACE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN.
MIXING WILL NOT BE AS GOOD TODAY DUE TO LIGHTER WINDS ALOFT...BUT
STILL LOWERED DEWPOINTS SINCE THINK WILL STILL BE ABLE TO TAP INTO
SOME OF THE BONE DRY AIR JUST ABOVE THE INVERSION. AS A
RESULT...HAVE DROPPED DEWPOINTS AND HUMIDITIES OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THIS AFTERNOON. HUMIDITIES COULD FALL
BETWEEN 20-25 PCT. FORTUNATELY...WINDS WILL BE MUCH LIGHTER
TODAY...SO SHOULD NOT SEE A REPEAT OF THE CRITICAL FIRE WEATHER
CONDITIONS. HIGHS MAINLY IN THE MID TO UPPER 60S AWAY FROM LAKE
MICHIGAN.
TONIGHT...A COLD FRONT WILL DECAY AS IT MOVES INTO NORTH-CENTRAL
WISCONSIN LATE. MID-LEVEL CLOUDS WILL CONTINUE TO SPREAD EAST AHEAD
OF THE FRONT...BUT GRADUALLY DISSIPATE IN THE PROCESS. SHOULD
THEREFORE SEE A PARTLY CLOUDY TO MOSTLY CLEAR NIGHT. WITH THE
THINNING CLOUDS...DO NOT THINK THERE WILL BE A DEEP ENOUGH CLOUD
LAYER FOR SPRINKLES OR LIGHT SHOWERS. LOWS MAINLY IN THE LOW TO MID
40S.
FRIDAY...THE FRONT WILL WASH OUT ACROSS NORTHERN WISCONSIN. MAY SEE
SOME CU DEVELOP OVER CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE
AFTERNOON...BUT THE NORTH SHOULD SEE AN INFLUX OF DRY AIR...THAT
WILL DROP HUMIDITIES NEAR 25 PCT IN THE AFTERNOON. HIGHS WILL BE
WARMER THAN TODAYS READINGS...AND RAISED THEM INTO THE UPPER 60S
NORTH TO MID 70S SOUTH.
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 257 AM CDT THU APR 16 2015
DRY CONDITIONS WILL CONTINUE FRIDAY NIGHT AND SATURDAY AS CANADIAN
HIGH PRESSURE BUILDS INTO THE STATE. NORTHWEST WINDS WILL TURN
TO THE EAST AND NORTHEAST LATE FRIDAY NIGHT AND SATURDAY. SATURDAY
AFTERNOON WILL AGAIN FEATURE VERY LOW AFTERNOON RELATIVE HUMIDITY
READINGS AWAY FROM THE LAKE...WITH READINGS DROPPING INTO THE 20
TO 40 PERCENT RANGE WITH THE LOWEST READINGS NORTH AND WEST OF THE
FOX VALLEY.
MEANWHILE...CLOSED UPPER LOW ACROSS THE CENTRAL PLAINS IS EXPECTED
TO OPEN UP AS 500MB TROUGH ACROSS SOUTHERN CANADA WILL BEGIN TO
LIFT THE SOUTHERN SYSTEM NORTHEAST TOWARDS THE REGION. QUIET A
SPREAD IN THE MODELS ON HOW QUICK THE RAIN WILL ARRIVE OVER THE
WEEKEND. THE WRF MODELS WAS QUICKEST...ALREADY BRINGING RAIN ON
SATURDAY TO PORTIONS OF THE AREA. THE GFS MODEL WAS IN THE MIDDLE
OF THE ROAD SOLUTION...WHILE THE CANADIAN/ECMWF MODEL WERE THE SLOWEST
SOLUTION WITH RAIN ARRIVING ON SUNDAY. TRENDED TOWARD THE SLOWER
SOLUTION FOR THE MEANTIME DUE TO BETTER CONSISTENCY FROM RUN TO
RUN. DID ADD A SMALL CHANCE OF RAIN ACROSS THE WEST LATE SATURDAY
NIGHT...AND THEN BOOSTED RAIN CHANCES INTO THE LIKELY CATEGORY ON
SUNDAY. DID RAISE RAIN CHANCES SUNDAY NIGHT AS WELL. THE 500MB
SYSTEMS WILL MERGE INTO A CLOSED UPPER LOW ACROSS THE UPPER
MIDWEST AND WESTERN GREAT LAKES REGION EARLY NEXT WEEK. THIS
WOULD SUPPORT A COOLER AND UNSETTLED PATTERN ACROSS THE REGION
ON MONDAY THROUGH WEDNESDAY. HAVE CHANCES OF SHOWERS EACH PERIOD...
ALONG WITH A LITTLE SNOW LATE AT NIGHT INTO THE EARLY MORNING
HOURS ON TUESDAY AND WEDNESDAY. IT IS WISCONSIN! TEMPERATURES
BY EARLY NEXT WEEK WILL RUN WELL BELOW NORMAL.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1021 PM CDT WED APR 15 2015
VFR CONDITIONS EXPECTED TONIGHT INTO THURSDAY. LIGHT EAST WIND AT
THE SURFACE WILL PREVAIL TONIGHT INTO THURSDAY BEFORE TURNING
VARIABLE OVER CENTRAL AND NORTH CENTRAL WISCONSIN WITH A WEAK
FRONTAL BOUNDARY. A WEAK DISTURBANCE WILL SLIDE OVER SOUTHEAST
WISCONSIN LATER TONIGHT INTO THURSDAY MORNING. A FEW SPRINKLES BUT
MORE THAN LIKELY VIRGA MAY FALL FROM A MID LEVEL DECK OF CLOUDS
OVER EAST CENTRAL WISCONSIN TOWARD THURSDAY MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
435 AM MDT THU APR 16 2015
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 435 AM MDT THU APR 16 2015
SIGNIFICANT STORM STILL EXPECTED TO IMPACT THE HIGHER ELEVATIONS
FROM LATE THIS AFTERNOON THROUGH MIDDAY FRIDAY. WATER VAPOR
IMAGERY SHOWS THE CLOSED UPPER LOW SPINNING JUST WEST OF THE FOUR
CORNERS REGION. WE ARE GETTING A BREAK IN THE PRECIP...HOWEVER
THIS WILL LIKELY BE SHORT LIVED (ONLY THROUGH THIS MORNING) AS
CLOUD TOPS ARE COOLING IN COLORADO. THE MODELS CONTINUE TO
INDICATE EXCELLENT LARGE SCALE LIFT DEVELOPING IN AREAS ALONG THE
COLORADO BORDER BY LATE THIS AFTN. UPWARD VERTICAL MOTION IS
MAXIMIZED FROM 21Z THIS AFTN THROUGH 12Z FRI IN THE SOUTHERN HALF
OF THE CWA. THIS IS DUE TO EXCELLENT UPPER LEVEL DIFFLUENCE AND
ISENTROPIC LIFT. WHILE WIDESPREAD SUBSTANTIAL QPF AMOUNTS ARE
VERY LIKELY...THE TRICKIER PART OF THIS FCST INVOLVED THE SNOW
LEVEL AND ASSOCIATED SNOW ACCUMULATIONS.
THE 00Z GUIDANCE CAME IN A BIT WARMER THAN YESTERDAY WITH RESPECT
TO SFC TEMPS FROM LATE THIS AFTN THROUGH FRIDAY MORNING. WARM AIR
ADVECTION IS OCCURRING AS 700MB TEMPS AT CHEYENNE RISE FROM -4C
THIS MORNING TO -1C BY FRI MORNING. THE CYS SOUNDING FROM BOTH THE
NAM AND GFS SHOW SFC TEMPS OF 2-3C WITH COMPLETE SATURATION
THROUGH TONIGHT. THUS...DESPITE THE STRONG LLVL LIFT...THINKING
IS THAT A MIX OF RAIN/SNOW OR ALL RAIN WILL OCCUR BETWEEN
ELEVATIONS OF 6250-5500 FT WITH THIS EVENT. DECIDED TO CANCEL THE
WINTER STORM WATCH FOR CENTRAL LARAMIE COUNTY AND EAST PLATTE
COUNTY WITH THIS REASONING...AND WILL LET DAY SHIFT SEE IF THE 12Z
GUIDANCE COMES IN ANY COOLER OR IF ANY DRIER AIR COULD CAUSE SOME
WET-BULBING. THE PRECIP WILL START OUT AS ALL SNOW AT ELEVATIONS
ABOVE 6500 FT THIS AFTN AND EARLY EVENING...WITH THE SNOW LEVEL
POSSIBLY RISING TO AROUND 7500 FT BY FRI MORNING. THE WINTER STORM
WATCH WAS UPGRADED TO A WARNING FROM JUST WEST OF CHEYENNE TO
ARLINGTON AND ALSO FOR THE SNOWY RANGE. WHILE TRAVEL WILL BE
AFFECTED ALONG INTERSTATE 80 FROM CHEYENNE TO ARLINGTON...THE
BIGGEST IMPACTS WILL LIKELY BE OVER THE FROM BUFORD TO THE
INTERSTATE 80 SUMMIT WHERE UP TO A FOOT OF SNOW IS FCSTED.
BY FRI AFTN THE UPPER LOW WILL HAVE MOVED INTO CENTRAL COLORADO.
THE MODELS SHOW VERY GOOD LIFT AND WIDESPREAD PRECIP ACROSS THE
CWA THROUGH THE AFTN. DECIDED TO END THE WINTER STORM HIGHLIGHTS
AT 18Z FRI AS SFC TEMPS WILL LIKELY BE ABOVE FREEZING ACROSS ALL
ZONES EXPECT MAYBE THE HIGHER ELEVATIONS OF THE SNOWY RANGE. THE
BAND OF PRECIP IS PROGGED TO SHIFT NORTHWARD FROM NORTHERN CARBON
TO THE NORTHERN NEBRASKA PANHANDLE BY FRI EVENING. IT IS AT THIS
TIME THAT DRIER AIR WILL WORK INTO THE SOUTHERN HALF OF THE CWA
AND PRECIP WILL DIMINISH. WITH MOST OF THE MODELS INDICATING QPF
AMOUNTS OF 1.25-2.0 INCHES FROM THIS AFTERNOON THROUGH FRIDAY
NIGHT FOR AREAS ALONG AND EAST OF THE LARAMIE RANGE...CONFIDENCE
IS HIGH THAT THIS SYSTEM WILL BRING WELL NEEDED MOISTURE TO THE
REGION.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 435 AM MDT THU APR 16 2015
A COOL AND SHOWERY PERIOD STILL EXPECTED ACROSS THE CWFA THIS
WEEKEND AND EARLY NEXT WEEK AS NORTHWEST FLOW PREVAILS. REMNANTS
OF THE UPPER LOW THAT WILL HAVE WOBBLED AROUND COLORADO FOR THE
BETTER PART OF 3 DAYS LATE THIS WEEK...WILL CARRY LINGERING
IMPACTS ACROSS THE REGION EVEN INTO SATURDAY. 00Z MEDIUM RANGE
GUIDANCE ARE CONSISTENT IN PINWHEELING A FINAL VORT LOBE SOUTH TO
NORTH THRU THE AREA ON SATURDAY. MODELS TARGET WRN AND NRN ZONES
WITH THE BEST AXIS OF PRECIP ON SATURDAY...THOUGH COOL MID-LEVEL
TEMPS WILL BE ENOUGH TO PRODUCE THE POSSIBILITY OF SHOWERS
EVERYWHERE. FINALLY...THE UPPER-LOW WILL FULLY PHASE INTO THE NRN
STREAM BY SUNDAY. 00Z MODELS HAVE TRENDED DEEPER/STRONGER WITH
KICKER SYSTEM HOWEVER. THIS WILL RE-ENFORCE PRECIP CHANCES FOR
SUNDAY. IT LOOKS SOMEWHAT DRIER MON-TUE...THOUGH STILL CANT
COMPLETELY RULE OUT SOME LIGHT SHOWER ACTIVITY ESPECIALLY IN AND
AROUND THE HIER TERRAIN. ANOTHER WEAK SHORTWAVE MAY BRING ADDL
SHOWER CHANCES TO THE AREA WED-THU. NONE OF THESE SHOWER CHANCES
WILL AMOUNT TO MUCH THO. TEMPS WILL BE THE COOLEST THIS WEEKEND
WITH HIGHS ONLY REACHING THE UPPER 40S TO NR 50 IN AND AROUND THE
MOUNTAINS WITH 50S TO NR 60 OUT ON THE ERN PLAINS. THESE SHOULD
WARM BACK INTO THE 50S AND MID 60S MON-WED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1034 PM MDT WED APR 15 2015
LATEST HRRR GUIDANCE USED FOR THE 06Z TAFS. WIDESPREAD IFR/LIFR
WITH NORTHEAST UPSLOPING FLOW. PRECIP BECOMES WIDESPREAD THURSDAY
AFTERNOON...WITH A POSSIBLE HEAVY SNOW EVENT THURSDAY NIGHT INTO
FRIDAY MORNING FOR SOUTHEAST WYOMING AND A WIDESPREAD MODERATE
RAIN EVENT FOR THE PANHANDLE AIRPORTS.
&&
.FIRE WEATHER...
ISSUED AT 347 AM MDT THU APR 16 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. A COOL AND VERY WET
PATTERN WILL BE IN PLACE THROUGH FRIDAY. WIDESPREAD RAIN ACROSS
THE LOWER ELEVATIONS AND SNOW IN THE MOUNTAINS WILL OCCUR.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO NOON MDT FRIDAY
FOR WYZ114>117.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON MDT
FRIDAY FOR WYZ103-105-106-110-112.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CAH
AVIATION...GCC
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1046 PM MDT WED APR 15 2015
.UPDATE...
ISSUED AT 1034 PM MDT WED APR 15 2015
RADAR CONTINUES TO SHOW MOISTURE STREAMING NORTH OUT OF NORTHERN
COLORADO THIS EVENING. WITH REPORTS OF 5-6 INCHES OF SNOW IN
LARAMIE...WENT AHEAD AND EXPANDED THE ADVISORY SOUTH AS WE COULD
SEE ANOTHER 1-3 INCHES OVERNIGHT. ATTENTION TURNS TO THURSDAY
NIGHT AS LOW IN COLORADO SPINS OFF ANOTHER STRONGER PIECE OF
ENERGY INTO THE LARAMIE RANGE. GUIDANCE SHOWING QPFS WELL OVER AN
INCH BEGINNING THURSDAY AFTERNOON AND PERSISTING INTO FRIDAY
MORNING. WENT AHEAD WITH A WINTER STORM WATCH FOR THE
MOUNTAINS...ADJACENT FOOTHILLS AND THE SNOWY RANGE. UPDATES SENT
OUT EARLIER.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 311 PM MDT WED APR 15 2015
TRICKY FORECAST THIS PERIOD WITH MAIN DIFFICULTIES BEING SNOW
LEVELS AND SNOWFALL AMOUNTS...AND AT WHAT TIMES THE HEAVIER
PRECIPITATION WILL OCCUR.
UPPER LOW TAKING SHAPE ALONG THE UTAH/COLORADO BORDER CURRENTLY
WITH AREAS OF RAIN AND SNOW ALONG AND WEST OF THE LARAMIE RANGE.
SOME CONVECTIVE ACTIVITY MOVING NORTH TOWARDS THE NEB PANHANDLE
FROM COLORADO AS WELL WITH A FEW LIGHTNING STRIKES NOTED IN THIS
ACTIVITY. EXPECT ALL THIS ACTIVITY TO CONTINUE MOVING NORTH AHEAD
OF AN IMPULSE RIDING UP THE EAST SIDE OF THE UPPER LOW THIS
EVENING THEN THERE SHOULD BE SOME LULL IN THE PCPN OVER THE
SOUTHERN PARTS OF THE CWA LATER THIS EVENING INTO THURSDAY BEHIND
THE IMPULSE WHILE THE MAIN UPPER LOW SINKS SLOWLY SOUTHWARD TO THE
4 CORNERS AREA. WILL MAINTAIN CURRENT WINTER WX ADVY AS IS AS THAT
AREA SHOULD STILL SEE MOSTLY SNOW.
CONDITIONS DETERIORATE AGAIN THURSDAY NIGHT AS THE UPPER LOW
DRIFTS SLOWLY ENE ACROSS COLORADO WITH NEXT SHORTWAVE LIKELY
ROTATING NORTH AND ACROSS THE CWA LATER THURSDAY NIGHT INTO
FRIDAY. HEAVIEST PCPN LOOKS LIKE IT WILL OCCUR THEN AND COULD GET
SOME DECENT SNOWS OVER HIGHER TERRAIN. 700MB TEMPS A BIT WARM
HOWEVER...ABOUT -2C...AND WARM GROUND MAY HINDER ACCUMULATIONS
SOME. WILL HOLD OFF ON ADDITIONAL HILITES AT THIS TIME AND LET
LATER SHIFTS LOOK AT NEWER RUNS. PCPN STILL FAIRLY WIDESPREAD ON
FRIDAY INTO FRIDAY NIGHT THOUGH MORE LIKELY OVER THE NORTH AS THE
IMPULSE CONTINUES TO RIDE NORTH AND NORTHWEST. SNOW LEVELS ALSO
RISING AS THE UPPER LOW FILLS SOME.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 311 PM MDT WED APR 15 2015
UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEKEND AS A CLOSED LOW
TRANSLATES EASTWARD INTO THE CENTRAL PLAINS. PRECIPITATION IS LIKELY
TO LINGER THROUGH AT LEAST SUNDAY WITH WEAK MIDLEVEL ENERGY ROTATING
WESTWARD ACROSS THE CWA. FAIRLY COOL TOO WITH GFS 700 MILLIBAR TEMPS
FAILING TO CLIMB ABOVE 0 DEG C. THE MODELS ARE IN GOOD AGREEMENT W/
A KICKER SYSTEM DIVING INTO THE DAKOTAS AT 12Z SUN. THIS PUSHES THE
OTHER SYSTEM TO THE EAST AND SENDS A COLD FRONT SOUTH. MEDIUM RANGE
MODELS SHOW ENOUGH H7-H3 MOISTURE TO SUPPORT SHOWERS CONTINUING INTO
SUN. WOULD PROBABLY BE COLD ENOUGH FOR ALL SNOW ON SUN...BUT THERMAL
PROFILES WOULD SUGGEST ALL RAIN OR A RAIN/SNOW MIX FROM THE NE STATE
LINE INTO THE WESTERN PANHANDLE PRIOR TO FROPA. MAINTAINED LOWER END
POPS INTO EARLY NEXT WEEK WITH COOL CYCLONIC FLOW ALOFT. INSTABILITY
SHOWERS CANNOT BE RULED OUT...SO IT IS HARD TO FORECAST DRY. NOTHING
MAJOR THOUGH. TEMPERATURES SHOULD STAY ON THE COOL SIDE FOR MOST OF
THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1034 PM MDT WED APR 15 2015
LATEST HRRR GUIDANCE USED FOR THE 06Z TAFS. WIDESPREAD IFR/LIFR
WITH NORTHEAST UPSLOPING FLOW. PRECIP BECOMES WIDESPREAD THURSDAY
AFTERNOON...WITH A POSSIBLE HEAVY SNOW EVENT THURSDAY NIGHT INTO
FRIDAY MORNING FOR SOUTHEAST WYOMING AND A WIDESPREAD MODERATE
RAIN EVENT FOR THE PANHANDLE AIRPORTS.
&&
.FIRE WEATHER...
ISSUED AT 311 PM MDT WED APR 15 2015
CONCERNS EXPECTED TO BE LOW THROUGH THE WEEKEND AS A COOL TO MILD
AIRMASS WILL RESIDE OVER THE DISTRICTS WITH PERIODS OF RAIN OR
SNOW BRINGING WETTING PRECIPITATION TO MUCH OF THE AREA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON FOR WYZ103-105>107-110-114>118.
WINTER WEATHER ADVISORY UNTIL 9 AM MDT THURSDAY FOR WYZ101-
103>106-109-110-115>117.
NE...NONE.
&&
$$
UPDATE...GCC
SHORT TERM...RE
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1120 PM MDT FRI APR 17 2015
.UPDATE...
ISSUED AT 919 PM MDT FRI APR 17 2015
UPDATED TO MODIFY POPS BASED ON 00Z GUIDANCE...FOCUSING
HIGHEST CHANCES OVER THE PIKES PEAK REGION AND UPPER ARKANSAS
AND CONTDVD NORTH OF HIGHWAY 50. CUT BACK ON POPS TO THE SOUTH
BUT WILL LEAVE ISOLD-SCT CHANCES OUT FOR THE HIGHER TERRAIN WITH
THE UPPER LOW OVERHEAD.
UPDATE ISSUED AT 844 PM MDT FRI APR 17 2015
MADE SOME ADJUSTMENTS TO THE WINTER HEADLINES BASED ON
OBS...TRENDS AND LATEST MODEL GUIDANCE. LOOKS LIKE THE HEAVIEST
AND MOST PERSISTENT PRECIP WILL BE OVER THE MTS NORTH OF HGWY
50 TONIGHT AND TOMORROW. SO...HAVE CANCELED THE ADVISORIES FOR THE
SANGRES AND WETS. EXTENDED PIKES PEAK AND THE SAWATCH TIL 00Z SUN
SINCE IT LOOKS LIKE PERIODS OF MODERATE SNOW WILL CONTINUE
TOMORROW. TELLER MAY ALSO HAVE TO BE EXTENDED BUT GIVEN THE
UNCERTAINTIES IN HOW THE BAND OF SNOW NORTH OF THE UPPER LOW WILL
SET UP...WILL LEAVE THE ENDING TIME FOR SAT MORNING FOR NOW. HRRR
HAS MOST OF THE HEAVIER QPF NORTH OF TELLER WHILE THE RAP AND NAM
HAVE IT DIRECTLY OVER TELLER. SO...AMOUNTS ARE MOST UNCERTAIN OVER
THE PIKES PEAK AREA BUT THE GOING ADVISORY COVERS THAT HAZARD FOR
NOW. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 256 PM MDT FRI APR 17 2015
CURRENTLY...THE UPPER LOW IS LOCATED OVER THE SW QUAD OF THE STATE
THIS AFTERNOON...AND WAS WRAPPING DRY AIR UP INTO PORTIONS OF SOUTH
CENTRAL AND SOUTHEAST CO EFFECTIVELY SHUTTING OFF PCPN AND EVEN
CLOUD COVER FOR PORTIONS OF THE CWA. BEFORE THE DRY AIR MOVED
IN...HEAVY SNOW WAS REPORTED OVER MANY OF THE AREA MTS AS WELL AS
THE UPPER ARKANSAS RIVER BASIN...ALONG WITH SIGNIFICANT RAINFALL
AMOUNTS ALL ALONG THE I25 CORRIDOR. CLOUD ENHANCEMENT WAS OCCURRING
AS OF 3 PM OVER THE S MTS...SLOWLY SPREADING NORTH. FARTHER
EAST...DRY AIR PUSHED INTO THE SE CORNER OF THE STATE AND HELPED TO
PUSH THE SEVERE THREAT N AND NE. A FEW THUNDERSTORMS HAVE STRUGGLED
ACROSS THE PLAINS THIS AFTERNOON AS LOWER DEWPOINTS HAVE ROBBED
LOW LEVEL ENERGY.
TONIGHT AND TOMORROW...THE MAIN QUESTION IS WHERE WILL THE UPPER LOW
GO. MODELS STILL INDICATE THAT IT WILL GRADUALLY MOVE NORTH INTO
CENTRAL COLORADO THIS EVENING...THEN EDGE DUE EAST THROUGH TOMORROW
AFTERNOON. AFTER A BRIEF LULL...WHICH WILL MOST LIKELY HAVE
CUSTOMERS SCRATCHING THEIR HEADS...ALL MODELS INCLUDING THE HI-RES
OFFERINGS SHOW SHOWERS REDEVELOPING OVER THE PALMER DVD AND
RAMPART RANGE...AS WELL AS THE CENTRAL MTS...N SANGRES AND
WETS...THIS EVENING AND OVERNIGHT. ADDITIONAL SNOW AMOUNTS DO NOT
LOOK AS SIGNIFICANT NOW AS THEY DID 12 HRS AGO...AND HANDLING OF
THE HIGHLIGHTS WAS EXCEPTIONALLY TRICKY. DECIDED TO PUSH ALL
ENDING TIMES OF HIGHLIGHTS TO 12Z TOMORROW MORNING...AND CONVERTED
SOME OF THE ONGOING WARNINGS TO ADVISORIES. FURTHER ADJUSTMENTS TO
THE POP AND HIGHLIGHT GRIDS WILL OCCUR UNDOUBTEDLY. AS FOR
TEMPS...FRESH SNOW COVER FOR MUCH OF THE HIGHER TERRAIN AND HIGH
VALLEYS WILL MAKE FOR A COLD NIGHT...AS WELL AS MODIFYING THE MAX
TEMP TOMORROW DOWNWARD A FEW DEGREES. LOOK FOR MAX TEMPS TOMORROW
IN THE 40S TO NEAR 50 F FOR THE HIGH VALLEYS...50S TO LOWER 60S
FOR THE E PLAINS...WITH AREAS THAT RECEIVED EXTENSIVE SNOW COVER
ON THE LOWER END. MOORE
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 256 PM MDT FRI APR 17 2015
OLD UPPER LOW OPENS UP AND PULLS AWAY TO THE EAST SAT NIGHT/SUNDAY.
ANOTHER LOBE OF ENERGY ROTATING AROUND THE BACK SIDE OF THE UPPER
LOW WILL SPREAD ANOTHER BAND OF SNOW SHOWERS INTO THE MTS/PALMER
DIVIDE SATURDAY EVENING...AND INTO THE SOUTHEAST PLAINS SAT
NIGHT/EARLY SUNDAY MORNING. OVERALL ACCUMULATIONS DO NOT LOOK LIKE
THEY WILL BE THAT HEAVY...BUT A COUPLE INCHES ACROSS THE CENTRAL
MTS AND PIKES PEAK REGION WILL BE POSSIBLE...WITH 1-2 ACROSS THE
PALMER DIVIDE. IT WILL BE SOMEWHAT UNSTABLE...SO THERE IS ALWAYS A
CHANCE FOR SOME LOCALLY HEAVY BURSTS OF SNOW...BUT THINK THESE
SHOULD BE FAIRLY LOCALIZED. MEANWHILE PRECIPITATION WILL FALL AS
RAIN ACROSS THE SE PLAINS EARLY BEFORE DIMINISHING BY LATE SUN
MORNING. WINDS REALLY INCREASE ACROSS THE AREA FOR SUNDAY BEHIND
THE SYSTEM WITH NORTH WINDS GUSTING TO 40 TO 50 MPH ACROSS THE
PLAINS. FORTUNATELY MANY PLACES HAVE HAD SOME RAIN...WHICH SHOULD
MINIMIZE BLOWING DUST CONCERNS SOME...AND COOLER AIR BEHIND THE
SYSTEM SHOULD KEEP RELATIVE HUMIDITY VALUES FROM REACHING CRITICAL
LEVELS WHICH SHOULD MITIGATE ANY FIRE WEATHER CONCERNS.
NORTHWEST FLOW KEEPS UNSETTLED WEATHER OVER THE REGION FOR MONDAY
AND TUESDAY WITH PRIMARILY AFTERNOON AND EVENING SNOW SHOWERS OVER
THE MOUNTAINS. ANOTHER REINFORCING NORTHERLY SURGE MOVES THROUGH THE
PLAINS ON MONDAY WHICH WILL ENHANCE EASTERLY UPSLOPE FLOW INTO THE
SOUTHEAST MOUNTAINS. THIS WILL RESULT IN SCATTERED SNOW SHOWERS AS
ANOTHER SHORTWAVE MOVES THROUGH NW FLOW ALOFT. GFS SPREADS THESE
SHOWERS EASTWARD ONTO THE PLAINS DURING THE EVENING HOURS THOUGH
PRECIPITATION WILL FALL MAINLY AS RAIN. WESTERN U.S UPPER RIDGE
TRANSLATES EASTWARD FOR TUESDAY WITH SHOWERS STAYING MORE CONFINED
TO THE MOUNTAINS. AGAIN...MAINLY LIGHT ACCUMULATIONS EXPECTED.
ANOTHER TROF MOVES INTO THE WESTERN U.S FOR THE LATTER PART OF THE
WEEK. UPPER RIDGE AXIS SHIFTS OVER CO FOR WEDNESDAY...THEN
GRADUALLY INTO THE PLAINS THURS AND FRI AS THE UPPER TROF MOVES
TOWARDS THE GREAT BASIN. LOTS OF VARIABILITY BETWEEN THE LONG RANGE
MODELS ON TIMING...BUT BOTTOM LINE IS FOR INCREASING SOUTHWEST FLOW
FOR THURSDAY AND FRIDAY...SPREADING A CHANCE OF SNOW SHOWERS INTO
THE CONTDVD REGION BY LATE WEEK. TEMPERATURES REBOUND ACROSS THE
PLAINS...THOUGH SOUTHEAST FLOW ADVECTS HIGHER DEW POINTS INTO THE
PLAINS BRINGING A CHANCE FOR THUNDERSTORMS. AS SOUTHWEST FLOW ALOFT
INCREASES...THIS SHOULD HELP DEVELOP A DRY LINE AND PUSH IT EASTWARD
ACROSS THE PLAIN...WITH THUNDERSTORMS POSSIBLE ALONG AND TO ITS EAST
THURS AFTERNOON. WILL HAVE TO WATCH THIS DEVELOPMENT AS DEEP
LAYER SHEAR LOOKS FAVORABLE FOR STRONG TO SEVERE THUNDERSTORMS...IF
SUFFICIENT MOISTURE CAN RETURN...BUT GIVEN THE UNCERTAINTIES IN
THE EVOLUTION OF THE SYSTEM...THESE DETAILS ARE LIKELY TO EVOLVE
OVER THE NEXT SEVERAL DAYS. -KT
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1106 PM MDT FRI APR 17 2015
LARGE UPPER LOW PRESSURE AREA SPINNING OVER THE MOUNTAINS THIS
EVENING AND DRIFTING SLOWLY EASTWARD. UPPER LOW HAS WEAKENED
CONSIDERABLY FROM THIS TIME YESTERDAY. CONDITIONS ARE MOSTLY VFR
ACROSS THE FLIGHT AREA EXCEPT FOR ISOLATED TO SCATTERED SNOW SHOWERS
PRODUCING POCKETS OF MVFR/IFR/LIFR FLIGHT CONDITIONS...MAINLY OVER
THE MOUNTAINS. UPPER LOW WILL DRIFT SLOWLY EASTWARD INTO SOUTHWEST
KANSAS FROM 06Z SATURDAY TO 06Z SUNDAY. AS IT DOES SO...ISOLATED
TO SCATTERED SHOWERS WILL CONTINUE OVER THE FLIGHT AREA...RESULTING
IN AREAS OF MVFR/IFR FLIGHT CONDITIONS AND POCKETS OF LIFR CONDITIONS
UNDER THE HEAVIER PRECIPITATION. KCOS...KPUB AND KALS TAF SITES
SHOULD REMAIN GENERALLY VFR THROUGH THE NEXT 24 HOURS. HOWEVER...IT
IS POSSIBLE THAT RAIN OR SNOW SHOWERS COULD BRIEFLY IMPACT ANY OF
THE TERMINALS...ESPECIALLY KCOS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR COZ059-063-
066-081.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT SATURDAY FOR COZ058-060-
061.
WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR COZ082.
&&
$$
UPDATE...ROSE
SHORT TERM...MOORE
LONG TERM...KT
AVIATION...LW
AREA FORECAST DISCUSSION
NWS TOPEKA KS
343 AM CDT Sat Apr 18 2015
.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT SAT APR 18 2015
Showers and thunderstorms developing this hour across northeast
Oklahoma into south central and north central Kansas, with cell
movement toward the north northwest and the cluster moving more
northerly. This area is forecast to move across the forecast area
through the morning hours today.
Struggle with the forecast continues to be timing and coverage of
precipitation chances. After initial energy lifts across Eastern
Kansas through early afternoon, next uncertainty will be for chances
later in the afternoon. HRRR develops a cluster of showers in south
central KS, but would anticipate a break between the systems with
subsidence behind the main wave inhibiting convective development.
Have higher chances in the morning, with lower chances middle
afternoon, followed by an increase from west to east through the
evening into the overnight hours as the main wave finally starts to
get an easterly push, from both a northern US shortwave and an upper
jet traversing the southern states. With a lull in precipitation
and possibly some better sunshine out west, this would boost
instability and chances for severe thunderstorms as late day storms
develop along the dryline to our west and along the northward
advancing warm front. Primary threat would be hail, but closer
proximity to these surface features in north central Kansas could
bring an isolated tornado risk there. General precipitation chances
continue in the overnight hours ahead of the upper low as it
continues to slowly move east. Highs for Saturday in the middle 70s
west to near 70 east, with lows in the 50s.
.LONG TERM...(Sunday through Friday)
Issued at 342 AM CDT SAT APR 18 2015
By Sunday morning the mid/upper low will be centered over SC KS and
NC OK as it progresses eastward. During this time the low will
become more of an open wave as another shortwave digs into the
northern plains and upper Midwest. These waves will bring a cold
front through the region during the day Sunday. In the morning the
better chance for showers and some thunder should be in southern KS
where the front and mid level low are more coupled in the vertical.
By 18Z the models are hinting at an increase of instability on the
order of about 1000 j/kg ahead of the front that should stretch
across eastern KS. Lapse rates are not overly impressive, and deep
layer shear could reach 30 kts. Although the better shear will be
further southeast over southern MO where the flow aloft is slightly
stronger. Therefore kept a mention of thunderstorms for east central
KS during the afternoon. A majority of the precip should clear the
area around 03Z in the evening.
A sharp pressure gradient behind the front will support northwest
surface winds around 15 to 25 mph with gusts as up to 35 mph
especially in NC KS. Cold air advection on the backside of the wave
drops temps into the lower 40s and upper 30s by Monday morning.
Winds do not completely decouple Sunday night so there is little
concern for frost. On Monday winds remain gusty with high temps
generally around 60 and partly sunny skies. Monday night will not be
the classic set up for frost with a expansive high building
southward, but the winds do decrease and temps are forecast to reach
the mid to upper 30s. Therefore could not rule out the possibility
for frost perhaps in preferred sheltered locations.
NW flow aloft develops over the region as the northern stream wave
deepens over the Great Lakes. The models are beginning to advertise
embedded shortwaves within the NW flow, which track over the plains
around mid week. This will bring small chances for either showers or
thunderstorms. Late in the week a southern wave crashes the southern
CA coast and tracks northeastward towards the center of the country.
There are some differences on how far north the instability reaches
ahead of the system, and there are additional waves in the NW flow
that could interfere with the southern stream system. Confidence in
any solution is low at this point.
&&
.AVIATION...(For the 06Z TAFs through 06Z Saturday Night)
Issued at 1134 PM CDT FRI APR 17 2015
Tricky forecast period as short term guidance has had difficulty
in determining timing and location of precip thru 12Z. However
latest models continue to show sct showers with a few embedded
TSRA impacting sites after 07Z at KMHK and 08Z at KTOP/KFOE. May
see brief MVFR conditions shortly after sunrise with the heavier
precip before it exits eastward early afternoon. Low confidence
thereafter as main system does not arrive into the area until
Sunday morning so will leave mention of VCTS.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Sanders
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1139 PM CDT Fri Apr 17 2015
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Saturday)
Issued at 346 PM CDT FRI APR 17 2015
Upper low continues to spin over the Rockies this afternoon with an
upper level jet rounding the base of the upper low and moving over
New Mexico. Earlier showers and thunderstorms were moving out of the
northern counties at 20Z. Some clearing was occurring across the
southern and western sections of the cwa this afternoon. Latest meso
analysis shows surface based CAPE around 500 to 1000 J/kg with an
uncapped atmosphere. Expect scattered convection to develop in
southwest Kansas along the dry line. additional scattered storms may
develop in south west and south central Kansas per the latest runs
of the RAP and HRRR. Models suggest additional development this
evening across western and central Kansas moving northeast into
north central Kansas with the increase and veering of the low level
jet overnight. Models are in agreement with a lobe of energy working
it`s way northeast out of Oklahoma later tonight and Saturday
morning. May see a repeat of this morning with an area of showers
and embedded thunderstorms moving across the area. Expect a break
for a few hours in the afternoon, then chances increase again with
storms developing again in the afternoon in western and central
Kansas as upward vertical motion increases with the advance of the
upper trough into the High Plains. Dryline looks to set up across
western Kansas with the GFS the furthest east in central Kansas.
Shear and instability will be favorable for some of the storms to be
strong to severe with large hail and winds the main hazards in the
late afternoon hours mainly west of a Herington to Washington
line.
.LONG TERM...(Saturday Night through Friday)
Issued at 346 PM CDT FRI APR 17 2015
Short range models are relatively consistent in moving surface low
and main piece of upper trough through eastern KS late Saturday
night and Sunday. Ahead of this system Saturday night, increasing
thunderstorm chances are expected, with some potential for severe
weather, with the best chance in our forecast area over the western
2/3. Shear parameters are not very impressive and amount of
sunshine and associated surface heating Sat afternoon and evening is
also a little suspect so this is not a high probability thing.
As the low and front move through on Sunday, some isolated thunder
may continue in the east in the morning, but showers associated with
cold air aloft just behind the front will continue precip chances
into the afternoon hours.
After that, subsidence and cold advection behind that system brings
in dry conditions and cooler temperatures for Sunday night through
Tuesday, with lows dipping into the upper 30s many places and highs
in the low to mid 60s.
Precip chances return to parts of eastern KS on Wednesday when weak
low-level warm advection and a weak wave in northwest flow aloft
interact. Latest ECMWF and GEM would indicate that the cool air at
the surface is more entrenched in place than the GFS, thus have
gone cooler than guidance for highs on Wednesday.
Beyond Wednesday, considerable differences exist between 12Z GFS and
ECMWF in upper flow pattern and precip chances. GFS and GFSEnsemble
places us in a more favorable pattern for a couple days of precip
for Thursday and Friday, while the ECMWF is slower in bringing a
shortwave trough out of the southwest U.S., and would give us the
better chances on Friday. Have gone with a general compromise
with 25 to 40 percent POPs for those days.
&&
.AVIATION...(For the 06Z TAFs through 06Z Saturday Night)
Issued at 1134 PM CDT FRI APR 17 2015
Tricky forecast period as short term guidance has had difficulty
in determining timing and location of precip thru 12Z. However
latest models continue to show sct showers with a few embedded
TSRA impacting sites after 07Z at KMHK and 08Z at KTOP/KFOE. May
see brief MVFR conditions shortly after sunrise with the heavier
precip before it exits eastward early afternoon. Low confidence
thereafter as main system does not arrive into the area until
Sunday morning so will leave mention of VCTS.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...53
LONG TERM...GDP
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
412 AM CDT Sat Apr 18 2015
.DISCUSSION...
Issued at 411 AM CDT SAT APR 18 2015
Overview: Closed and cut-off upper low now over central CO will be
the primary weather driver for the weekend. Feature will open up by
Sunday and move east in response to a shortwave trough digging
southeast through the Northern Rockies. Expect to see a several
rounds of active convection Saturday and Sunday.
Today - Sunday:
While eyes have been fixated on the closed upper low now over CO/NM
the real weather makers will be periodic vorticity lobes and
associated layered frontogenesis that rotate northeast out from
under the upper low. Little going on over the CWA early this morning
as we`re lacking any discernible feature to initiate any convection.
But we are finally seeing the long awaited next round of convection.
Regional radars have recently lit up from OK northward through
central KS albeit further west than we`ve been expecting. Favor
following the HRRR reflectivity trends, which have slowed down the
arrival of the KS/OK convection and latest NAM mass fields/h7
vorticity prog. Thus have pared back PoPs significantly for first
part of morning and slowed the eastward expansion of precipitation.
Even still this is a forecast which will need adjusting throughout
the day as the convection tied to the upper low has had repeated
false starts as well as expanding too fast to the east.
Thickening cloud cover and rain-cooled air will affect temperatures
over the western half of the CWA more so than the eastern half where
precipitation will move in later in the day. Precipitable water
values around two standard deviations above normal suggest potential
for 1"+ rains through tonight. Weak shear and MUCAPEs under 1000J/kg
favor convection remaining below severe limits.
Should see a lull in the rain later tonight and first part of Sunday
before the next wave of convection moves in. The upper low will have
opened up by then and will accelerate eastward. Anticipate convection
increasing as it moves east through the CWA in response to improving
upper level dynamics and low-level convergence associated with a
cold front. However, once again the 0-6km shear of 20-25kts and
modest MUCAPEs favor convection being sub-severe.
Monday - Tuesday:
A fairly deep upper trough stretching from MN through the Mid MS
Valley will influence our weather with widespread subsidence on the
backside of the trough. Abundant solar insolation will help offset
cold air advection but still result in below average temperatures.
Wednesday - Friday:
As the upper trough shifts east through the Great Lakes an upper
ridge will build eastward through the Rockies and into the
Central/Southern Plains. Medium range models are in agreement that a
cold front will surge through the region on Wednesday. However, they
disagree on whether or not convection will be generated. Moisture
fields look minimal and believe any shower activity will be widely
scattered.
As we get into Thursday and Friday the ECMWF and GFS both lift a
shortwave out of the southwestern U.S. but the GFS appears
unrealistic in deepening a surface over the Central High Plains and
spreading warm advection convection too far downstream. Will use a
blended forecast but overall confidence low for Thursday`s PoPs but
timing looks better for the PoPs on Friday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1129 PM CDT FRI APR 17 2015
VFR conditions will likely prevail at the terminals through the rest
of the overnight hours as the forecast for storms looks to have
slowed. Storms still look likely in the morning, but now it appears
that it will be after sunrise before anything sweeps across our
terminals. Thunderstorms are forecast to redevelop in the late
afternoon hours. Otherwise, easterly surface wind overnight will veer
to the south through the morning hours, with speeds remaining less
then 10 knots.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Cutter
DISCUSSION...MJ
AVIATION...Cutter
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT SAT APR 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT SAT APR 18 2015
SPC SUGGESTED SIGNIFICANT SEVERE WEATHER POTENTIAL THIS AFTERNOON
AND EARLY THIS EVENING ACROSS PARTS OF SOUTHWEST AND NCNTL NEB. A
PORTION OF THE LOW PRESSURE ACROSS SWRN KS THIS MORNING IS
EXPECTED TO LIFT NORTHEAST THROUGH SCNTL AND ERN NEB THIS
AFTERNOON SETTING UP A UNSTABLE WARM SECTOR FROM ROUGHLY IMPERIAL
TO ONEILL.
ALTHOUGH THE RAP IS FAIRLY QUIET THE NAM AND HRRR SBN MODELS
SUGGEST REASONABLE POTENTIAL FOR CONVECTIVE DEVELOPMENT THIS AFTN
IF SKIES PARTIALLY CLEAR ALLOWING FOR TEMPERATURES TO RISE INTO
THE MID AND UPPER 60S. SATELLITE SHOWS CLEARING THIS MORNING
ACROSS CNTL HIGH PLAINS OF KS/COLO AND IT IS BELIEVED THIS
CLEARING WILL MOVE INTO SCNTL NEB THIS AFTN.
THE STORM ACTIVITY COULD BEGIN AS EARLY AS 18Z IN THE SOUTHWEST
WITH THE NAM SOLN OR AS LATE AS 21Z-00Z IN THE HRRR MODEL.
SATELLITE TIMING TOOLS INDICATE THE CLEARING ACROSS KS COULD
REACH SOUTHWEST NEB BY 13-15Z THIS MORNING WHICH WOULD PROVIDE A
GOOD START FOR MODEST HEATING GIVEN THAT THIS CLEARING AREA WOULD
TEND TO FILL IN WITH DEVELOPING CUMULUS.
ONE WEAKNESS ARE THE WIND FIELDS 500MB AND BELOW WHICH ARE LIGHT
PRODUCING BULK SHEAR VALUES OF 30KT OR LESS WHICH MIGHT SUPPORT
MORE OF HEAVY RAIN THREAT. STILL TEMPERATURES ALOFT WILL BE VERY
COLD AS THE H500MB LOW ACROSS COLO MOVES EAST TO NEAR
LIMON/SPRINGFIELD. WINDS AT 300MB ARE STRONG NEAR 65KT
POTENTIALLY ENHANCING UPDRAFTS AND PROVIDING VENTILATION.
FREEZING LEVELS ARE NEAR 5KFT SUPPORTING A LOW TOP STORM
ENVIRONMENT AND GOOD POTENTIAL FOR HAIL. THE NAM IS PRODUCING
AROUND 2000 J/KG OF CAPE AT NORTH PLATTE AND BROKEN BOW WHILE THE
RAP AND OTHER MODELS SHOW HALF OR LESS THAT VALUE.
NORTHWEST WINDS WILL SWEEP IN FROM THE WEST IN THE WAKE OF THE
DISTURBANCE TONIGHT. THIS SHOULD PRODUCE DRYING AND DECREASING
RAIN CHANCES FROM MIDNIGHT ONWARD.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 328 AM CDT SAT APR 18 2015
SUNDAY WILL SEE THE STRONG LOW PRESSURE WEAKENING AS IT PUSHES
EAST WHILE A TROUGH DIGS ACROSS THE CANADIAN PLAINS. SOME
LINGERING SUNDAY MORNING SHOWERS ARE POSSIBLE IN THE EASTERN
ZONES...HOWEVER THE BIGGER EVENTS OF THE DAY WILL BE THE CAA AND
INCREASING NW WINDS. AS THE LOW PUSHES ACROSS KS...DRY AIR WILL
QUICKLY FILL IN BEHIND...RESULTING IN DECREASING CLOUDS FROM WEST
TO EAST IN THE MORNING. BY AFTERNOON SHOULD SEE MOSTLY SUNNY
SKIES FOR ALL. THE SUN WILL COMBINE WITH THE STRONG NW WINDS
/GUSTING TO 30 TO 40 MPH/ TO PROMOTE GOOD MIXING OF THE BL AND
OFFSET THE CAA AND TEMPS PUSH INTO THE 50S.
EARLY IN THE WEEK THE TROUGH DIGS TOWARDS THE GREAT LAKES REGION
AND ABSORBS THE SOUTHERN LOW. ELONGATED SFC HIGH PRESSURE BUILDS
ACROSS THE HIGH PLAINS. THE ACTIVE WEATHER IS WELL TO THE NE
ALTHOUGH A FEW UPPER LEVEL DISTURBANCES WILL RIDE ALONG THE NW
FLOW OVERHEAD AND BRING SOME PASSING CLOUDS AT TIMES. LIMITED
MOISTURE IN THE LOWER LEVELS AND MODELS/FORECAST ARE DRY. TEMPS
TO START THE WEEK WILL BE CHILLY IN THE MORNING WITH MOST AREAS
NEAR OR BELOW THE FREEZING MARK. STILL A COUPLE OF WEEKS FROM
TYPICAL LAST FREEZE FOR MOST OF THE AREA...SO NO HEADLINES NEEDED
YET. HIGHS REBOUND NICELY WITH A WARMING TREND WITH 60S MAYBE 70
FOR WED AND THURS.
EYES THEN FOCUS ON A TROUGH AS IT DIGS ACROSS THE SOUTHWEST.
MODELS IN GOOD AGREEMENT DEVELOPING A CLOSED 500 MB LOW NEAR SRN
CAL BY THURS. THE LOW THEN LIFTS TOWARDS THE 4 CORNERS WHILE
BECOMING AN OPEN WAVE. THE WAVE WILL THEN PUSH ACROSS THE PLAINS
TO END THE WEEK. THIS WILL BRING A RETURN OF THE ACTIVE
WEATHER...AND WILL HAVE POPS TOWARDS THE END OF THE EXTENDED
PERIOD. STILL HAVE SOME LOCATION AND TIMING ISSUES TO IRON OUT
WHICH IS TYPICAL THIS FAR OUT SO POPS KEPT BELOW 50 PERCENT FOR
NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1213 AM CDT SAT APR 18 2015
THUNDERSTORMS IN SOUTHWEST NEBRASKA WILL STILL BE CAPABLE OF
PRODUCING HAIL AND HEAVY RAIN THROUGH THE NIGHT INTO EARLY
SATURDAY. AS FOR HAVING THUNDER AT ANY ONE POINT...THE
PROBABILITY IS LOW. PROJECTING FROM THE CURRENT RADAR IMAGERY
INDICATES THAT THUNDERSTORMS WILL PASS CLOSE ENOUGH TO KLBF TO BE
INCLUDED IN THE TAF UNTIL ABOUT 08Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORMAN OK
419 AM CDT SAT APR 18 2015
.DISCUSSION...
SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING IS THE
MAIN CONCERN.
RAIN CHANCES THIS MORNING LOOK TO BE MAINLY CONFINED TO LOCATIONS
EAST OF I-35 WHERE MOST LATEST RADAR ECHOES WERE OCCURRING FROM A
WEAK IMPULSE ROTATING AROUND A MID/UPPER LOW IN SOUTHERN
COLORADO. NO SEVERE STORMS ARE EXPECTED WITH THIS ACTIVITY...JUST
SOME LOCALIZED HEAVY RAIN. MOST OF THIS ACTIVITY MAY END BY 8 AM
IF THE LATEST HRRR RUNS ARE CORRECT. MOST LOCATIONS WILL REMAIN
DRY THIS MORNING.
ADDED PATCHY FOG MENTION THROUGH 11 AM THIS MORNING ACROSS PARTS
OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS WHERE SOME PARTIAL
CLEARING...ABUNDANT LOW LEVEL MOISTURE...AND LATEST HRRR RUNS
FAVOR SOME DEVELOPMENT. DOUBT IT WILL GET TOO WIDESPREAD OR DENSE.
THIS AFTERNOON AND EVENING...ISOLATED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL DEVELOP ACROSS THE AREA. CAPPING WILL BE RATHER
WEAK. WITH MORE SUN COMPARED TO YESTERDAY...THINK CONVECTIVE
TEMPERATURES WILL BE REACHED RATHER EASILY IN THE 2 TO 5 PM TIME
FRAME. FIRST DEVELOPMENT MAY BE FOCUSED IN WESTERN OKLAHOMA AND
WESTERN NORTH TEXAS NEAR A DEVELOPING DRYLINE. WENT NEAR GUIDANCE
RAIN CHANCES. EXACTLY WHERE AND WHEN STORMS OCCUR REMAINS TRICKY
TODAY AND TONIGHT.
IN REGARDS TO SEVERE POTENTIAL THIS AFTERNOON AND EVENING...
BELIEVE THERE WILL BE SOME SEVERE STORMS WITH LARGE HAIL AS THE
MAIN CONCERN. THE AIR WILL BE MODERATELY UNSTABLE WITH MLCAPE
1500-2500 J/KG. STRONG 0-6 KM SHEAR 30-50 KT SUPPORTS SUPERCELLS
AND MULTICELLS. STRONG 0-3 KM SHEAR VALUES 25-45 KT AND VERY COLD
MID LEVELS WITH 500 MB TEMPERATURES AROUND -18C COULD SUPPORT VERY
LARGE HAIL IN SOME CELLS AS LONG AS CONVECTION IS NOT TOO
WIDESPREAD. SOME DAMAGING WINDS MAY OCCUR AS WELL IF STORMS CAN
ORGANIZE INTO CLUSTERS AND LINES. TORNADO POTENTIAL APPEARS TO BE
LIMITED DUE TO WEAK LOW LEVEL SHEAR...THOUGH NOTICED THE LATEST
RAP13 INDICATED STRONGER LOW LEVEL WINDS POSSIBLY DEVELOPING IN
SOUTHWESTERN OKLAHOMA IN THE 5 TO 9 PM TIME FRAME WHICH MAY
INCREASE THIS POTENTIAL. WILL CLOSELY MONITOR.
LOCALLY HEAVY RAINFALL MAY AGAIN OCCUR LATE THIS AFTERNOON AND
TONIGHT...THOUGH STORM MOTIONS WILL BE FASTER WHICH MAY LIMIT THE
DURATION OF HEAVY RAINFALL IN ONE GIVEN LOCATION.
MOST STORMS WILL MOVE INTO EASTERN OKLAHOMA AFTER MIDNIGHT
TONIGHT...ALLOWING FOR MOIST AND COOL CONDITIONS. WOULD NOT BE
SURPRISED IF SOME FOG FORMED...BUT DID NOT MENTION DUE TO LOW
CONFIDENCE.
ON SUNDAY...A FEW SHOWERS AND STORMS MAY LINGER MAINLY OVER
NORTHERN OKLAHOMA...THOUGH APPEARS THE SEVERE POTENTIAL WILL SHIFT
IN FAR EASTERN OKLAHOMA AND POINTS EAST. WITH LINGERING WEAK
INSTABILITY AND COLD MID/UPPER LEVELS...A FEW STORMS WITH SMALL
HAIL COULD OCCUR. BREEZY CONDITIONS WILL DEVELOP. THERE IS AN
OUTSIDE CHANCE WINDS COULD APPROACH ADVISORY CRITERIA WITH GUSTS
OVER 40 MPH IN NORTHWEST OKLAHOMA. WENT WITH THE WARMER SIDE OF
GUIDANCE TEMPERATURES THINKING SOME SUN WILL OCCUR...ESPECIALLY
EARLY IN THE DAY.
SUNDAY NIGHT THROUGH FRIDAY...A WET PATTERN MAY CONTINUE WITH
RAIN CHANCES REMAINING IN THE FORECAST MOST DAYS. THERE ARE SOME
MODEL DISCREPANCIES WITH WEATHER FEATURES...THUS FORECAST
CONFIDENCE REMAINS LOW. SOME STRONG TO SEVERE STORMS MAY OCCUR
TUESDAY THROUGH FRIDAY WITH NEARBY MOISTURE AND INSTABILITY.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 77 55 72 45 / 50 70 20 10
HOBART OK 79 50 72 42 / 50 20 10 0
WICHITA FALLS TX 81 53 76 46 / 50 30 10 0
GAGE OK 77 47 66 38 / 40 20 20 10
PONCA CITY OK 75 54 71 41 / 50 70 60 10
DURANT OK 76 58 76 49 / 50 60 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
25/17
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
141 AM EDT SAT APR 18 2015
.SYNOPSIS...
DRIER AND WARMER AIR WILL SPREAD INTO THE REGION THROUGH SATURDAY. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA SATURDAY NIGHT INTO
SUNDAY...ACCOMPANIED BY ABUNDANT MOISTURE AND MORE RAINFALL. A COLD
FRONT WILL CROSS THE AREA ON MONDAY...USHERING IN SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 140 AM...WIDESPREAD PRECIP BEGINNING TO MOVE EAST OF THE AREA.
EXPECT THIS TREND TO CONTINUE WITH ONLY SPOTTY LIGHT SHRA FOR THE
REST OF THE NITE. OTHERWISE...GOING FCST ON TRACK WITH CLOUDY SKIES
AND MILD TEMPS. PATCHY DENSE FOG LIKELY ALONG THE UPPER SAVANNAH
RIVER VALLEY AND LITTLE TENNESSEE BASIN...WITH AREAS OF DENSE FOG
POSSIBLE. PATCHY DENSE FOG COULD DEVELOP ELSEWHERE AS WELL. MAIN
UPDATES WERE FOR CURRENT CONDITIONS.
AS OF 1030 PM EDT FRIDAY...WIDESPREAD SHOWERS STILL COVER THE
UPSTATE AND PORTIONS OF THE MOUNTAINS...SO CONTINUING CATEGORICAL
POPS FOR ANOTHER COUPLE OF HOURS UNTIL THE SHORTWAVE AXIS PUSHES
THROUGH STILL LOOKS GOOD. TEMPERATURES ON TRACK FOR THE MOST PART SO
ONLY MINOR TWEAKS TO HOURLY TRENDS.
AS OF 730 PM EDT FRIDAY...HAVE BUMPED UP POPS ACROSS MOST OF THE
AREA THIS EVENING INTO THE OVERNIGHT PERIOD TO ACCOUNT FOR FAIRLY
WIDESPREAD LIGHT RAIN/SHOWERS MOVING ACROSS THE AREA...FORCED BY THE
RELATIVELY STRONG SHORTWAVE MOVING ACROSS THE SOUTHEAST THIS
EVENING. IF THE HRRR IS TO BE BELIEVED...THESE SHOWERS COULD LINGER
OVERNIGHT AND PAST SUNRISE...AND WILL EVALUATE FURTHER FOR THE LATE
EVENING UPDATE. BEST MOISTURE REMAINS ACROSS THE UPSTATE AND
NORTHEAST GEORGIA BUT STILL SEEING SOME LIGHT RAIN ACROSS THE
MOUNTAINS AND FOOTHILLS. STILL SEEING SOME SBCAPE VALUES HOLDING ON
ACROSS THE PIEDMONT BUT THESE SHOULD BEGIN DROPPING RAPIDLY WITH
SUNSET...SO HAVE PULLED BACK ON THUNDER WORDING THIS EVENING AND
OVERNIGHT. OTHER GRIDS IN GOOD SHAPE FOR THE MOST PART...WITH ONLY
MINOR TWEAKS TO ACCOUNT FOR HOURLY TRENDS.
AS OF 430 PM EDT FRIDAY...VERY LITTLE CHANGE TO PREVIOUS THINKING
FOR THE NEAR TERM. PRECIPITATION BEGINNING TO OVERSPREAD WESTERN AND
SOUTHWESTERN ZONES AS EXPECTED. NEW GUIDANCE BEGINNING TO PULL BACK
A LITTLE ON CONVECTIVE POTENTIAL...WITH INCREASING CLOUD COVER AND
MOISTENING ATMOSPHERE WHAT LITTLE SBCAPE WAS BEGINNING TO CREEP INTO
THE MESOANALYSES OVER THE PAST COUPLE OF HOURS IS ONCE AGAIN FALLING
OFF. LOOKING AT HI-RES REFLECTIVITY FORECASTS...DEFINITELY STARTING
TO LOOK LIKE MORE STRATIFORM RAIN OR SHOWERS WITH THE POSSIBILITY OF
EMBEDDED THUNDER. HAVE LEFT WEATHER WORDING AS IS FOR NOW SINCE
CURRENTLY ADVERTISED THUNDER IS CHANCE AT BEST...BUT WILL REEVALUATE
MORE THOROUGHLY FOR NEXT NEAR-TERM UPDATE. ONLY MINOR TWEAKS TO
TEMPS AND DEWPOINTS TO UPDATE TRENDS.
AS OF 245 PM EDT FRIDAY...THE SYNOPTIC PATTERN HAS NOT CHANGED ALL
THAT MUCH FROM YESTERDAY...OR DAYS PAST FOR THAT MATTER. IT STILL
FEATURES ROTATING CLOSE UPPER LOW OVER THE FOUR CORNERS WHILE DEEP
SOUTHWEST WAA PREVAILS ACROSS THE SOUTHEAST UNITED STATES. AT
THE SURFACE...SPRINGTIME WEDGE STARTING TO ERODE AS EXPECTED THIS
AFTERNOON AS WINDS HAVE VEERED SOUTHERLY ACROSS NORTHEAST GA AND THE
UPSTATE...ALONG WITH A FEW LOCATIONS OVER THE NC PIEDMONT.
FURTHERMORE...H5 SHORT WAVE AND ASSOCIATED VORTICITY MAXIMA
CONTINUES TO SLIDE EAST ACROSS THE DEEP SOUTH WITH A BROAD AREA OF
PRECIPITATION ACCOMPANYING. LATEST SPC MESO ANALYSIS NOT ALL THAT
IMPRESSIVE AS INSTABILITY REMAINS NEARLY NONEXISTENT ACROSS THE FCST
AREA. MODELS FAVOR IMPROVING LAPSE RATES WITH HEATING THIS
AFTERNOON...HOWEVER STILL SKEPTICAL AS PRECIP SHIELD AND ASSOCIATED
LOW OVERCAST SKY COVER WILL LIMIT HEATING. NEVERTHELESS...THE FCST
DOES FEATURE INCREASING POPS THROUGH THE AFTERNOON/EVENING HOURS
WITH CHANCES FOR THUNDER MENTIONED...AND WILL CONTINUE WITH SUCH IN
THE HWO. POPS WILL LOWER AFTER MIDNIGHT AS THE PRIMARY UPPER WAVE
EJECTS TO THE EAST...AND A WEAK/DRY BACK DOOR FRONT SLIDES SOUTHWARD
ACROSS THE REGION. HELD ON TO TOKEN SLIGHT/CHANCE POPS THROUGH
MORNING TO ACCOUNT FOR ANY RESIDUAL SHRA ALONG THE BOUNDARY. LATEST
SOUNDINGS DO NOT SUGGEST AS MUCH MID DRYING AS THE PREVIOUS
RUN...THEREFORE NOT ALL THAT CONFIDENT IN AREAS OF DENSE FOG
OVERNIGHT. THAT SAID...WOULDNT BE SURPRISED TO SEE ISOLATED CASES OF
SUCH ACROSS THE NC PIEDMONT/FOOTHILLS JUST AHEAD OF THE INTRUDING
BOUNDARY WHEN WINDS ARE CALMEST AND THE PBL IS DECOUPLED.
SATURDAY WILL BE HIGHLIGHTED BY DECREASING CLOUDINESS AS DOWNSLOPING
FLOW PREVAILS AMONGST INCREASING HEIGHTS ALOFT AS AXIS OF SHORTWAVE
RIDGE SHIFTS OVERHEAD. POPS WILL INCREASE YET AGAIN THROUGH THE DAY
AS FCST SOUNDINGS INDICATE MODEST DESTABILIZATION WITH HEATING.
HOWEVER EXPECTING UPPER RIDGING TO PROVIDE SOME SUBSIDENCE THEREFORE
KEPT POPS AT OR BELOW CHANCE LEVELS THROUGH THE DAY. TEMPERATURES
ON SATURDAY WILL DEPEND HIGHLY ON HOW SOON THE SKY COVER SCT OUT.
TOOK A MIDDLE OF THE ROAD APPROACH AS IT PERTAINS TO GUIDANCE...WITH
THE FCST FEATURING HIGHS 3-5 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
AS OF 200 PM FRIDAY...TWO AREAS OF CONCERN TO DEAL WITH IN THE SHORT
TERM. THE FIRST WILL BE A PERIOD OF HEAVY RAIN ON SUNDAY AND THEN A
RISK OF SEVERE STORMS ON MONDAY.
THE UPPER RIDGE OVER THE SOUTHEAST U.S. WILL TRANSLATE EASTWARD
SATURDAY NIGHT AS THE UPPER LOW THAT HAS BEEN OVER THE 4-CORNERS
BEGINS TO MOVE EAST THANKS TO A DIGGING TROUGH MOVING SE OUT OF THE
CANADIAN PRAIRE. A SHORT WAVE OUT AHEAD OF THE UPPER LOW WILL MOVE
NE FROM THE GULF COAST AND ACROSS THE WESTERN CAROLIANS AND NE GA ON
SUNDAY. AT THE SURFACE...A WARM FRONT WILL APPROACH FROM THE SW ON
SUNDAY. ALL OF THIS WILL RESULT IN ALL TYPES OF FORCING ACROSS THE
REGION ON SUNDAY. PWATS WILL BE IN THE 1.5-1.7" RANGE WITH A 35-45
KT SELY 850 MB JET INTO THE BLUE RIDGE. WILL RAMP POPS UP QUICKLY TO
CATEGORICAL FROM WEST TO EAST BY MIDDAY SUNDAY...THEN DECREASE
RAPIDLY FROM WEST TO EAST LATE SUNDAY AS THE AXIS OF DEEP MOISTURE
AND FORCING SHIFT EAST. HEAVY RAIN LOOKS TO BE A GOOD BET...BUT THE
RELATIVELY QUICK MOVEMENT OF THE SYSTEM SHOULD PRECLUDE ANY SERIOUS
HYDRO ISSUES. BLENDING THE MODEL CONSENSUS AND WPC QPF GUIDANCE...
RESULTS IN GENERALLY 1.5"-2.0" FROM LATE SATURDAY NIGHT INTO SUNDAY
NIGHT. THE HIGHEST AMOUNTS AS USUAL ARE EXPECTED TO BE NEAR THE BLUE
RIDGE ESCARPMENT WHERE 2-3" OF RAIN CAN BE EXPECTED. THESE VALUES
ARE UNDER THE 12 TO 24 HOUR FFG. THERE MAY BE SOME LOCALIZED
FLOODING BUT WIDESPREAD FLOODING IS UNLIKELY. HOWEVER...WILL
CONTINUE TO MENTION HEAVY RAIN IN THE HWO. AN IN SITU WEDGE WILL
RESULT IN COOL TEMPS ON SUNDAY AND WILL THEREFORE TREND TOWARD
CONSRAW GUIDANCE TEMPS.
SOME DEGREE OF CLEARING SHOULD OCCUR SUNDAY NIGHT AS THE AXIS OF
DEEP MOISTURE SHIFTS NE AND A DOWNSLOPE WIND COMPONENT THROUGH THE
COLUMN DEVLOPS. ON MONDAY...A COLD FRONT WILL MOVE ACROSS THE REGION
FROM WEST TO EAST. BOTH THE NAM AND GFS INDICATE THAT THE ATMOSPHERE
WILL DESTABLIZE BY AFTERNOON WITH CAPES MOST LIKELY INCREASING TO
BETWEEN 1000 AND 1500 J/KG PER GFS AND ECM. ALSO...0-6KM SHEAR
INCREASES TO ABOUT 40KT. THIS MAY SUPPORT SOME ORGANIZION TO THE
CONVECTION AS THE COLD FRONT MOVES THROUGH. THE 12Z NAM MODEL
REFLECTIVY SUGGESTS THAT A BROKEN LINE OF CONVECTION WILL ACCOMPANY
THE FRONT ACROSS THE AREA ON MONDAY WITH A FEW SEVERE STORMS
POSSIBLE. WITH THE AREA SOLIDLY IN THE WARM SECTOR ON MONDAY...MAX
TEMPS ARE EXPECTED TO BE ABOUT 5 DEGREES ABOVE CLIMO.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM FRIDAY...MONDAY NIGHT...SFC HIGH PRESSURE WILL BUILD
OVER THE FORECAST AREA IN THE WAKE OF A PASSING COLD FRONT. 12Z GFS
INDICATES THAT H85 TEMPERATURES WILL COOL BY 5 C FROM 0Z TO 12Z
TUESDAY...A LITTLE LESS COOLING ON THE ECMWF. USING A BLEND OF
GUIDANCE...I WILL FORECAST LOW TEMPERATURES FROM THE UPPER 40S
WITHIN THE MTN VALLEYS TO MID 50S EAST. ON TUESDAY...BROAD HIGH
PRESSURE WILL REMAIN ACROSS THE CWA. THE REGION SHOULD SEE MOSTLY
SUNNY CONDITIONS WITH A LIGHT SOUTHWEST WIND. TEMPERATURES SHOULD
RESPOND TO THE LATE APRIL SUN AND WEAK DOWNSLOPING...FORECAST TUES
HIGHS SLIGHTLY ABOVE NORMAL.
WEDNESDAY THROUGH FRIDAY...THE GFS AND ECMWF GENERALLY AGREE THAT A
LARGE CLOSED MID LEVEL LOW WILL REMAIN ACROSS THE NORTHEAST AND
EASTERN CANADA...AS A RIDGE LINGERS OVER THE SOUTHERN PLAINS. THE
HEIGHTS ACROSS THE CWA WILL LIKELY REMAIN NW TO SE THROUGH THE
PERIOD. THE MODELS ARE IN LESS AGREEMENT WITH THE PLACEMENT AND
TIMING OF SFC FEATURES...PRIMARILY WEAK FRONTS AND PRESSURE CENTERS.
I AM MORE CONFIDENT TIMING MID LEVEL FEATURES WITHIN THE NW FLOW
ACROSS THE SOUTHERN APPALACHIANS...I WILL FAVOR THE ECMWF.
OVERALL...I WILL KEEP CONDITIONS DRY ON WED...BUT MOISTURE WILL
INCREASE THROUGH THE DAY. A SHORT SERIES OF MID LEVEL S/W ARE
FORECAST TO RIPPLE ACROSS THE CWA THURSDAY THROUGH FRIDAY.
TEMPERATURES SHOULD RANGE CLOSE TO NORMAL WITH AFTERNOON DEWPOINTS
ONLY IN THE 40S. GIVEN THE TRACK OF THE MID LEVEL DISTURBANCES AND
WEAK DIURNAL INSTABILITY...I WILL INDICATE ONLY SCHC POPS ACROSS THE
MTNS ON THURSDAY. FORECAST SOUNDINGS SHOW GREATER INSTABILITY FRIDAY
AFTERNOON...FROM THE MTNS TO THE PIEDMONT. THE COMBINATION OF THE
PASSING DISTURBANCE AND INSTABILITY SHOULD SUPPORT SCT COVERAGE
ACROSS THE MTNS AND ISO EAST.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...CANNOT RULE OUT A BRIEF MVFR VSBY OR CIG AS SHRA MOVE
ACROSS THE AIR FIELD EARLY THIS MORNING. HOWEVER...DO EXPECT
CONDITIONS TO FALL TO MVFR THEN IFR TOWARD DAYBREAK AFTER THE PRECIP
ENDS. EXPECT LOW VFR BY NOON OR SO AS FORCING ENDS AND LOW LEVEL
MOISTURE MIXES OUT. MVFR COULD RETURN BY THE END OF THE PERIOD...BUT
MORE LIKELY TOWARD THE END OF THE NEXT TAF ISSUANCE. LIGHT NORTH OR
CALM WIND EARLY THIS MORNING BECOMES LIGHT NE...THEN ENE THRU THE
DAY.
ELSEWHERE...PRECIP WILL SOON MOVE EAST OF THE AREA AND CONDITIONS
WILL FALL TO IFR BEFORE DAYBREAK. IN FACT...LIFR LIKELY...LIKE THE
CURRENT CONDITIONS AT KAND. EXPECT A SLOW IMPROVEMENT TO LOW VFR
THRU THE MORNING. MVFR AND PRECIP MOVE BACK IN FROM THE WEST
TONIGHT. CALM WIND BECOMES NE THIS MORNING...THEN ENE TONIGHT. KAVL
WILL SEE NLY WIND BECOMING SLY TODAY...REMAINING THERE TONIGHT.
OUTLOOK...DEEPER MOISTURE WILL RETURN ALONG A WARM FRONT THROUGH
SUNDAY...WITH HEAVY RAINFALL AND WIDESPREAD RESTRICTIONS LIKELY ONCE
AGAIN. THUNDERSTORMS WILL THEN BE POSSIBLE THROUGH MONDAY AS A COLD
FRONT REACHES THE AREA FROM THE WEST.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-00Z
KCLT MED 66% MED 62% LOW 57% HIGH 100%
KGSP MED 75% MED 62% MED 64% HIGH 100%
KAVL HIGH 100% HIGH 87% LOW 59% HIGH 100%
KHKY HIGH 100% HIGH 87% MED 66% HIGH 100%
KGMU HIGH 91% MED 69% MED 71% HIGH 100%
KAND MED 75% MED 75% LOW 52% HIGH 90%
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...CSH
NEAR TERM...CDG/RWH/TDP
SHORT TERM...LG
LONG TERM...NED
AVIATION...RWH
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
420 AM CDT Sat Apr 18 2015
.SHORT TERM...
(Today and Tonight)
There is a threat for severe thunderstorms across the eastern half
of West Central Texas today as an upper level trough associated with
the upper low near the Four Corners moves across the region. The
main threats will be large hail and damaging winds. SPC has placed
much of the area east of the dryline in a slight risk for severe
thunderstorms today.
Latest radar is showing showers developing across the mountains in
northern Mexico, south of Sanderson, in association with the next
approaching shortwave as can be seen on water vapor satellite
imagery. This could bring a round of showers and thunderstorms to
West Central Texas this morning before the main upper trough moves
across later this afternoon.
The dryline is forecast to move east today as the RUC model progs
this front from Haskell to just east of San Angelo to Sonora by
early evening. This dryline should trigger scattered thunderstorms
this afternoon as the following ingredients come together: dewpoints
ranging from the upper 50s to the lower 60s, moderate 0-6km shear,
MU CAPE Values 1500-2000 J/KG, a weak capping inversion, approaching
upper trough and a right rear entrance region of the southern stream
upper level jet flowing across the area. These parameters should
set the stage for the development of a few supercells today,
resulting in large hail and damaging winds. These storms may
continue into the early evening hours before dissipating.
Highest Pops were placed across the Northwest Hill Country extending
north to Brownwood. Went closer to the warmer MAV MOS for
temps as the dry warm air invades the western part of the region
today.
26
.LONG TERM...
(Sunday through Friday)
Cold front will move through Sunday. Dry southwest to west winds
ahead of the front will not only preclude rain chances, but also
give a boost to temperatures, being downslope compression. Still,
cold advection will bring cooler temperatures Sunday, with highs
in the 70s.
Isolated dryline thunderstorms possible mid and late week. West
Central Texas will be under a broad upper ridge, so widespread
showers or thunderstorms not expected. Could see a few highs
approach 90s, especially Wednesday and Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 82 55 79 49 72 / 30 20 5 5 5
San Angelo 84 54 82 50 75 / 30 10 5 5 5
Junction 82 56 85 52 75 / 50 30 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
26/04
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
415 AM CDT SAT APR 18 2015
.DISCUSSION...
THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS
BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE
OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL
STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO
NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH
WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL
SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE
NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS
SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE
BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR
FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW...
THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF
SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF
THE BOUNDARY TODAY.
THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS
STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING
DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS
MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST
ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE
PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR
WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE
SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE
DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE
STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH
TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE
STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH
AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS
WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE
TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX
COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT
TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE
HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD
REAGGRAVATE FLOODING ISSUES.
AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE
A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS
EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL
FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY
FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE
THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL
ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE
AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION
BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY
AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT...
AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP
INTO THE 40S MONDAY AND TUESDAY MORNING.
ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE
EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT
AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO
SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING
RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY.
EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH
UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS
THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE
NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS
IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY
PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP
TEMPERATURES CLOSER TO CLIMATOLOGY.
25
&&
.AVIATION...
/ISSUED 635 PM CDT FRI APR 17 2015/
FOR THE 00Z TAFS...TRACKING THE NORTH/SOUTH ORIENTED LINE OF
THUNDERSTORMS MOVING EAST TOWARDS THE DFW METROPLEX IS THE PRIMARY
FORECAST CONCERN.
THE LINE OF STORMS JUST WEST OF TARRANT COUNTY HAS BEEN LOSING
INTENSITY FOR THE MOST PART...AND AS A RESULT HAS BEEN
CONSISTENTLY SLOWLY DOWN WITH REGARDS TO ITS EASTERLY PROGRESS.
THE MOST INTENSE PART OF THE LINE IS LOCATED OVER FAR SOUTHWESTERN
TARRANT COUNTY...MOVING EAST NOW AT ABOUT 20 MPH. FOR THE MOST
PART THIS LINE OF STORMS WILL BE CAPABLE OF PRODUCING 20 TO 30 MPH
WIND GUSTS...HEAVY RAINFALL...AND FREQUENT LIGHTNING AS IT MOVES
OVER AREA TAF SITES.
THE MORE INTENSE LINE OF STORMS OVER FAR SOUTHERN TARRANT COUNTY
WILL BE CAPABLE OF PRODUCING WIND GUSTS OF 40 TO 45 MPH AS WELL AS
HEAVY RAINFALL AND FREQUENT LIGHTNING. THIS MORE INTENSE LINE OF
STORMS APPEARS ON TRACK TO MOVE OVER KGKY AIRPORT...REMAINING JUST
SOUTH OF KFTW...KDFW...KAFW...AND KDAL AIRPORTS.
WILL LIKELY HAVE TO KEEP AMENDING THE TAFS FOR TIMING
CONSIDERATIONS AS THE STORMS ROLL ACROSS THE DFW AREA. BEHIND THE
MAIN LINE OF STORMS...LIGHT RAIN SHOWERS ARE EXPECTED TO PERSIST
FOR A COUPLE OF HOURS BEFORE ALL PRECIPITATION ENDS ACROSS THE DFW
AREA.
OTHER THAN STORMS...IFR CIGS ARE EXPECTED TO BUILD OVER NORTH AND
CENTRAL TEXAS FROM THE SOUTH EARLY TOMORROW MORNING. DID NOT SEE
ANY REASON TO CHANGE THE TIMING OF THE ONSET OF IFR CIGS FROM THE
PREVIOUS FORECAST...BUT MAY NEED TO ADJUST THE TIMING ONCE STORMS
HAVE DISSIPATED...ALLOWING FOR AN EVALUATION OF WHERE OUTFLOW
BOUNDARIES END UP. DID NOT HAVE ENOUGH CONFIDENCE IN THE TIMING OF
STORMS ON SATURDAY TO INCLUDE THEM IN THE TAFS AT THIS TIME.
STORMS MAY ONCE AGAIN THREATEN AREA TAF SITES TOMORROW AFTERNOON
OR EVENING.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 60 80 53 73 / 40 50 10 5 5
WACO, TX 80 60 83 53 75 / 40 50 10 5 5
PARIS, TX 75 58 77 50 70 / 50 40 20 5 0
DENTON, TX 77 57 79 49 72 / 40 50 10 5 5
MCKINNEY, TX 78 58 79 51 73 / 40 50 10 5 0
DALLAS, TX 80 62 81 54 74 / 40 50 10 5 5
TERRELL, TX 78 60 80 52 74 / 40 50 10 5 5
CORSICANA, TX 79 61 82 52 75 / 40 50 20 5 5
TEMPLE, TX 79 60 84 53 74 / 40 50 10 5 5
MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
411 AM CDT Sat Apr 18 2015
.SHORT TERM...
(Today and Tonight)
There is a threat for severe thunderstorms across the eastern half
of West Central Texas today as an upper level trough associated with
the upper low near the Four Corners moves across the region. The
main threats will be large hail and damaging winds. SPC has placed
much of the area east of the dryline in a slight risk for severe
thunderstorms today.
The dryline is forecast to move east today as the RUC model progs
this front from Haskell to just east of San Angelo to Sonora by
early evening. This dryline should trigger scattered
thunderstorms this afternoon as the following ingredients come
together: dewpoints ranging from the upper 50s to the lower 60s,
moderate 0-6km shear, MU CAPE Values 1500-2000 J/KG, a weak capping
inversion, and a right rear entrance region of the southern stream
upper level jet flowing across the area. These parameters should
set the stage for the development of a few supercells today,
resulting in large hail and damaging winds. These storms may
continue into the early evening hours before dissipating.
Highest Pops were placed across the Northwest Hill Country extending
north to Brownwood. Went closer to the warmer MAV MOS for
temps as the dry warm air invades the western part of the region
today.
26
.LONG TERM...
(Sunday through Friday)
Cold front will move through Sunday. Dry southwest to west winds
ahead of the front will not only preclude rain chances, but also
give a boost to temperatures, being downslope compression. Still,
cold advection will bring cooler temperatures Sunday, with highs
in the 70s.
Isolated dryline thunderstorms possible mid and late week. West
Central Texas will be under a broad upper ridge, so widespread
showers or thunderstorms not expected. Could see a few highs
approach 90s, especially Wednesday and Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 82 55 79 49 72 / 30 20 5 5 5
San Angelo 84 54 82 50 75 / 30 10 5 5 5
Junction 82 56 85 52 75 / 50 30 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
26/04
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
401 AM CDT SAT APR 18 2015
.SHORT TERM (TODAY THROUGH SUNDAY)...
AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS
MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN
EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY
AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL
LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18
HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE
EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE
WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND
WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE
FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS
SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO
-10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT
DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC
DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE
EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER
A SLIGHT RISK OF SEVERE THUNDERSTORMS.
HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF
STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE
SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND
MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING
STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE
EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP
CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR
TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS
ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS
EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW
PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH
MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE
WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT
AN ISOLATED STORMS ACROSS THE FAR EASTERN COUNTIES SUNDAY
AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT
WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT
TEMPS INTO THE 50S AREAWIDE.
&&
.LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS
AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY.
SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR
SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY
AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - -
AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - -
NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - -
BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - -
DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10
GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - -
HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - -
SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - -
LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10
SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - -
STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...17
SYNOPTIC/GRIDS...29
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1147 PM CDT FRI APR 17 2015
.UPDATE...
SOME MINOR CHANGES TO THE FORECAST INCLUDE INSERTING A MENTION OF
FOG AND INCREASING MINIMUM TEMPERATURES FOR TONIGHT. THE DRYLINE
HAS MOVED FARTHER WEST THAN MODELS FORECAST BRINGING IN MOIST AIR
ON THE CAPROCK. MODELS HAVE TRENDED TOWARDS DEVELOPING FOG IN THE
MOIST AIR THROUGH MID MORNING. FURTHERMORE...T/TD SPREADS OFF THE
CAPROCK WERE ALREADY RUNNING BETWEEN 1-2 DEGREES. IT IS STILL
NEBULOUS ON WHETHER AREAS ON THE CAPROCK WILL SEE FOG OR NOT. THE
DRYLINE RECENTLY ENCOUNTERED A WESTWARD MOVING BOUNDARY WHICH HAS
GREATLY SLOWED THE PROGRESSION OF THE DRYLINE. AT SOME POINT...THE
DRYLINE WILL LIKELY BEGIN MOVING EAST. OVERNIGHT TEMPERATURES WERE
GENERALLY RAISED ON EASTERN PORTIONS OF THE CAPROCK WHERE THIS
MOISTURE HAS INVADED.
&&
.AVIATION...
VERY MOIST AIR NEAR THE SURFACE WILL LIKELY BRING FOG INTO THE
KCDS TERMINAL EARLY SATURDAY MORNING. IT REMAINS UNCLEAR ON
WHETHER FOG WILL MAKE IT INTO KLBB OR KPVW. A DRYLINE BOUNDARY IS
CLOSE TO BOTH TERMINALS WHICH MAKES IT UNCERTAIN ON WHETHER THE
LOW LEVEL MOISTURE WILL STAY IN THE VICINITY OF EITHER TERMINAL.
IF MOISTURE DOES HANG ON...THEN FOG AND LOW CIGS WILL BE POSSIBLE
AT KLBB AND KPVW. BREEZY WINDS WILL DEVELOP OUT OF THE SOUTHWEST
DURING THE AFTERNOON AT ALL TAF SITES.
&&
PREV DISCUSSION... /ISSUED 321 PM CDT FRI APR 17 2015/
SHORT TERM...
DRYLINE AT 19Z EXTENDED FROM JUST WEST OF SILVERTON SOUTH TO WHITE
RIVER LAKE AND NEAR LAKE ALAN HENRY. THIS BOUNDARY HAS BEEN FORCED
WEST ALL DAY BY CONVECTIVE OUTFLOWS FARTHER EAST AND RECENT RUNS OF
THE RUC HAVE THE DRYLINE ARRIVING ALONG INTERSTATE 27 BY THIS
EVENING...PERHAPS MUCH SOONER. INSTABILITY-WISE...A NARROW AXIS OF
SBCAPE AROUND 1000 J/KG MAY FULFILL SOME TSTORMS ALONG AND EAST OF
THE DRYLINE THROUGH THE EVENING...BUT VISUAL TRENDS OF TOWERING AND
MODERATE CU SUGGEST DEEPER ASCENT IS LACKING. WATER VAPOR IMAGERY
INDICATE THIS AREA IS BATTLING SUBSIDENCE ALOFT DUE TO AN AXIS OF
PERSISTENT DEEP CONVECTION 60-100 MILES FARTHER EAST. BECAUSE OF
THIS AND LIMITED NWP SUPPORT...POPS HAVE BEEN SCALED BACK TO SLIGHT
CHANCE FOR MOST AREAS OFF THE CAPROCK.
AS THE FOUR CORNERS LOW BEGINS LIFTING NORTHEAST TONIGHT...LOWER
TROPOSPHERIC WINDS WILL VEER MORE WESTERLY ACROSS THE WESTERN HALF
OF THE CWA AND HELP TO NUDGE THE DRYLINE EASTWARD BEFORE DAYBREAK
SAT. MODELS AGREE THE DRYLINE WILL MIX OUT OF OUR EASTERN ZONES BY
MIDDAY AHEAD OF BREEZY SW WINDS...BUT ANY DISRUPTION TO THIS SUCH AS
WE SAW TODAY WITH CONVECTIVE OUTFLOWS COULD SUPPORT A MORE WESTERLY
DRYLINE LOCATION AND NECESSITATE MODIFICATIONS TO OUR DRY FORECAST
FOR SATURDAY. WHEREVER THE DRYLINE ENDS UP...DEEP CONVECTION SHOULD
EASILY UNFOLD BY SAT AFTN UNDER WEAK INHIBITION...STRONGER CYCLONIC
FLOW AND A FAVORABLE MID-LEVEL COLD POCKET OF -20C AT 500MB.
LONG TERM...
COLD FRONT PROGGED TO MOVE THROUGH THE FCST AREA SUNDAY MORNING
WITH ENOUGH COLD ADVECTION TO RESULT IN HIGHS MAINLY UPPER 60S AND
LOWER 70S WHILE ALSO SCOURING LOW LEVEL MOISTURE OUT OF THE FCST
AREA. MAY SEE SOME CONVECTION ATTEMPT TO DEVELOP ON THE HIGH
TERRAIN OF NRN NM/SRN COLO AND BE DRIVEN TO THE SE ON NWLY UPPER
FLOW...BUT WITH DRY LOW LEVELS WOULD EXPECT IT TO HAVE A HARD
TIME GETTING THIS FAR TO THE SE. SITUATION CHANGES SOME MONDAY
WHEN SOUTH AND SE WINDS BEGIN TO BRING MOISTURE BACK INTO THE
AREA. LOOKS LIKE HIGH TERRAIN CONVECTION WILL HAVE A BETTER CHANCE
OF MOVING THROUGH THE PANHANDLE AND INTO NRN PARTS OF THE FCST
AREA.
THE MIDDLE PART OF THE WEEK WILL THEN BE ONE WITH POSSIBILITY OF
WEAKLY-FORCED DIURNAL DRYLINE STORMS WITH LOW LEVEL MOISTURE
INCREASING WITH TIME...CONFLUENT FLOW ALOFT TRANSITIONING TO WEAK
UPPER RIDGING. 20-30 PCT STORM CHANCES TUESDAY THROUGH FRIDAY LOOK
FINE WITH THIS SYNOPTIC SETUP.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 40 70 40 65 / 0 0 10 0
TULIA 48 73 44 67 / 0 0 10 0
PLAINVIEW 49 73 45 68 / 0 0 0 0
LEVELLAND 45 75 46 70 / 0 0 0 0
LUBBOCK 50 76 47 71 / 0 0 0 0
DENVER CITY 44 74 47 71 / 0 0 0 0
BROWNFIELD 45 76 48 72 / 0 0 0 0
CHILDRESS 56 79 51 73 / 20 10 10 0
SPUR 54 79 50 73 / 20 0 0 0
ASPERMONT 57 81 52 77 / 20 10 10 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
154 AM EDT SAT APR 18 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT AND SATURDAY BRINGING
DRY AND WARM WEATHER FOR THE START OF THE WEEKEND. A COMPLEX STORM
SYSTEM PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN
SUNDAY INTO SUNDAY NIGHT BEFORE A COLD FRONT CROSSES THE REGION WITH
A CHANCE OF SHOWERS AND POTENTIALLY STRONG STORMS ON MONDAY. DRY AND
COOL CONDITIONS WILL PREVAIL FOR THE MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1012 PM EDT FRIDAY...
ISOLD SHOWERS HAVE DISSIPATED AND SEE NO REASON FOR ANY NEW ONES
TO FIRE UP OVERNIGHT...OTHER THAN ONE OR TWO ACROSS NORTHERN NC
GIVEN MUCAPE VALUES STILL AROUND 300-500 J/KG. ALSO KEEPING AN EYE
ON THE NORTHERN EDGE OF AREA OF SHOWERS INTO SW NC...WHICH IS
AHEAD OF A SHORT WAVE NEAR CHATTANOOGA...AS SOMETHING COULD SNEAK
INTO OUR NW NC MTNS AFTER MIDNIGHT...BUT MOST GUIDANCE AGREES
THIS WILL STAY JUST TO OUR SOUTH. LEFT SLIGHT CHC POP ACROSS
SOUTHERN EDGE OF FCST AREA THROUGH MUCH OF THE NIGHT...BUT REMOVED
MENTION EVERYWHERE ELSE. TRENDS LOOK BETTER FOR MORE CLEARING FROM
WEST LATE...AND THUS POSSIBILITY OF SOME PATCHY VALLEY FOG WITH
WET GROUND SO ADDED THAT AS WELL...MAINLY TO MTN VALLEYS.
OVERNIGHT TEMPS LOOK ON TRACK AT THIS POINT.
PREV DISC AS OF 635 PM EDT FRIDAY...
UPDATE TO REFLECT CURRENT MAINLY ISOLD COVERAGE OF
SHOWERS FROM FOOTHILLS INTO SOUTHSIDE VA. INCLUDED A COUPLE HOURS
OF CHC POPS ACROSS SOUTHSIDE THROUGH EARLY EVENING WITH CLUSTER
OF SHOWERS THERE...AND SO FAR NOT SEEING ANY SIGNS OF EVEN
INTERCLOUD LIGHTNING WITH CELLS NEAR MTV AND DAN...BUT KEEPING
ISOLD THUNDER IN FCST GIVEN SBCAPES OF 500-800 J/KG....AND SOME
ISOLD LTG IN CELLS JUST NORTHEAST OF BUCKINGHAM COUNTY. ALL THIS
ACTIVITY SHOULD SLOWLY DIMINISH AS IT DRIFTS SOUTHEASTWARD INTO
FAR NORTHERN NC BY 8 OR 9PM...AND RECENT HRRR RUNS SEEM TO BE
DOING A BETTER JOB CAPTURING THE SPARSITY OF THE SHALLOW
CONVECTION AND WEAKENING INTO THE EVENING HOURS WITH LOSS OF
HEATING.
SOME OF THE MORE WIDESPREAD LIGHT RAIN OVER FAR SW NC AND UPSTATE
SC WILL SLIDE TO THE NORTHEAST IN ADVANCE OF WEAK SHORT WAVE
HEADING EAST OUT OF TN...BUT PREVIOUS THINKING THAT IT WILL REMAIN
SOUTH OF THE FCST AREA STILL LOOKS ON TRACK. WE DO KEEP A
LINGERING SLIGHT CHC POP ACROSS NW NC MTNS UNTIL A LITTLE AFTER
MIDNIGHT JUST IN CASE...BUT THEN DROP ALL POPS TOWARD MORNING.
PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY...
AT THE SFC...HIGH PRESSURE WILL SLOWLY NOSE SOUTH INTO THE
EASTERN OHIO VALLEY BRINGING A LIGHT NORTH WIND. A SHALLOW LAYER
OF MOISTURE NEAR THE SURFACE WILL REMAIN...WHICH WILL RESULT IN
POCKETS OF FOG...ESPECIALLY WHERE CLOUDS ARE ABSENT TO THE NORTH.
LEANED TOWARD THE WARMER GUIDANCE VALUES WITH CLOUDS.
FOR SATURDAY...HEIGHTS BUILD IN ADVANCE OF A DEEP UPPER LEVEL TROF
IN THE WEST AND TEMPS SHOULD AGAIN WARM WELL INTO THE 70S AND THE
80S IN THE EAST.
A WEAK LOW LEVEL EAST FLOW COMBINED WITH A NOSE OF HIGHER THETA-E
AIR IN NW NC INTO FAR SW VA MAY SPARK ISOLATED SHOWERS/STORMS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 330 PM EDT FRIDAY...
FOCUS THROUGH THIS PERIOD REMAINS ON A STRONG NEGATIVELY TILTED
UPPER TROUGH PROGGED TO LIFT RAPIDLY NORTHEAST ACROSS THE REGION
SUNDAY INTO EARLY MONDAY. MEANWHILE...ANTECEDENT HIGH PRESSURE
WILL MOVE OFF THE MID-ATLANTIC COAST INTO A NEAR CLASSIC WEDGE
POSITION. STRONG PVA/ISENTROPIC LIFT INDUCED RAINFALL INTO THE
WEDGE AIR MASS WILL ENHANCE/INTENSIFY THE WEDGE SUNDAY.
RAINFALL/QPF WILL BE THE MAIN CONCERN AS THE WEDGE KEEPS A VERY
STABLE/COOL AIR MASS IS PLACE. MOIST SOUTHEAST...UPSLOPE FLOW
ALONG THE BLUE RIDGE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS
WATAUGA NORTHEAST TOWARD FLOYD. AS NOTED YESTERDAY...HOWEVER...THE
SYSTEM WILL REMAIN HIGHLY PROGRESSIVE...LIMITING THE PERIOD OF
HEAVIER RAINFALL TO 12 HOURS OR LESS. WPC HAS PARTS OF THE NC/VA
SOUTHERN VA PIEDMONT OUTLOOKED FOR EXCESSIVE RAINFALL. THE MAIN
CONCERN WITHIN THIS AREA WOULD BE WATAUGA THROUGH
ASHE/WILKES...WITH LESS CONCERN TOWARD THE DANVILLE AREA WHERE
ANTECEDENT CONDITIONS ARE RELATIVELY DRY. IN ADDITION...THE
CONVECTIVE THREAT THROUGH THE HEAVIER RAIN PERIOD AS NOTED ABOVE
IS MINIMAL TO NONE...WHICH SHOULD FURTHER REDUCE THE FLASH FLOOD
THREAT. WILL RE-EVALUATE AGAIN TOMORROW...BUT AT THIS POINT NO
NEED FOR A FLOOD/FLASH FLOOD WATCH. ONE MAY EVENTUALLY BE NEEDED
FOR A SMALL AREA INCLUDING THE NW NC MOUNTAINS AND THE ADJACENT
FOOTHILLS. WENT WELL BELOW GUIDANCE ON MAX TEMPS IN THE WEDGE
SUNDAY...BUT AT OR ABOVE GUIDANCE ON MONDAY IN THE WARM SECTOR.
MAX TEMPS MONDAY WILL BE A GOOD 20 DEGREES WARMER IN MOST AREAS
THAN ON SUNDAY.
MONDAY IS A DIFFERENT STORY. A SIGNIFICANT WARM SECTOR WILL SURGE
NORTHWARD INTO THE REGION MONDAY AFTERNOON BEHIND THE DEPARTING
UPPER TROUGH AND AN APPROACHING STRONG COLD FRONT ASSOCIATED WITH
A DEEPENING BROAD UPPER TROUGH ACROSS THE GREAT LAKES. SEVERAL OF
THE MODELS CONTINUE TO ADVERTISE GOOD POTENTIAL FOR STRONG
THUNDERSTORMS MONDAY AFTERNOON...WITH SIGNIFICANT SVR PARAMETER
NEAR 20000 ACROSS THE PIEDMONT...CAPES NEARING 2000 J/KG WITH AT
LEAST 20-30KTS OF 0-2KM LOW-LEVEL SHEAR AND LIS NEAR -4C. SPC DAY
4 OUTLOOK SUGGESTS THAT DAMAGING WINDS WOULD BE THE MAIN CONCERN
WITH ANY CONVECTION...MOST LIKELY LINEAR ORIENTED...THAT DEVELOPS
ALONG/IN ADVANCE OF THE COLD FRONT MONDAY AFTERNOON/EVENING. THIS
ACTIVITY QUICKLY MOVES EAST OF THE REGION MON AFTERNOON.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 345 PM EDT FRIDAY...
A TRANSITION TO A PATTERN MORE REMINISCENT OF WINTER CONTINUES TO
BE IN THE CARDS FOR THE EARLY AND MID PART OF NEXT WEEK AS A DEEP
AND BROAD UPPER TROUGH BUILDS INTO THE CENTRAL/EASTERN U.S. BY
TUESDAY...500MB HEIGHTS DROP INTO THE 560DM RANGE AND 850MB TEMPS
PLUNGE TOWARD THE 0C MARK ACROSS THE NORTH BY MIDWEEK.
ANTICYCLONIC FLOW...A SERIES OF EMBEDDED UPPER DISTURBANCES...AND
COLD ADVECTION WILL KEEP VARIABLE CLOUDINESS AND POTENTIALLY
UPSLOPE SHOWERS IN PLACE ACROSS THE MOUNTAINS. THE CLOUDS AND
CYCLONIC FLOW WILL HOLD MAX TEMPS INTO THE 50S AND LOWER 60S ACROSS
THE MOUNTAINS THROUGH MUCH OF THE LATER HALF OF NEXT WEEK...WHILE
60S TO 70S PREVAIL TO THE EAST WITH DOWNSLOPE NORTHWEST FLOW AND
SIGNIFICANTLY GREATER AMOUNTS OF SUNSHINE. AT THIS POINT A
DISTURBANCE ON WED APPEARS TO BE THE MOST SIGNIFICANT IN
POTENTIALLY BRINGING SHOWERS EAST OF THE MOUNTAINS. HAVE NOT
INTRODUCED ANY THUNDER AT THIS POINT GIVEN THE LOW-LEVEL
COLD/STABLE AIR MASS.
BY MID-WEEK...THE GFS/ECMWF BEGIN TO DIVERGE ON THE OVERALL
PATTERN...WITH THE ECMWF KEEPING THE DEEP UPPER TROUGH IN PLACE
ACROSS THE NORTHEAST AND A STRONGER NW FLOW INTO OUR REGION AS
WELL...WHILE THE GFS DEPICTS THE UPPER TROUGH LIFTING FURTHER
NORTH AND PLACING A ZONAL FLOW WITH A BAROCLINIC ZONE STUCK ACROSS
OUR CWA. THIS RESULTS IN SIGNIFICANT DIFFERENCES BETWEEN
MOISTURE/POPS ACROSS OUR CWA BETWEEN THE TWO MODELS...WITH THE GFS
VERY WET AND THE ECMWF MUCH DRIER...KEEPING THE BAROCLINIC ZONE
MUCH FURTHER SOUTH. HAVE JUST ADVERTISED CHC POPS FOR NOW UNTIL A
BETTER HANDLE ON THIS PATTERN AND TIMING IS OBTAINED. TEMPERATURES
ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE MID PART OF THE
WEEK...GRADUALLY TRENDING CLOSER TO NORMAL BY THE END OF THE
PERIOD.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 145 AM EDT SATURDAY...
STARTING THE TAF PERIOD WITH WEAK HIGH PRESSURE AND LIGHT WINDS
OVER THE MID ATLANTIC REGION. SOME FOG HAD DEVELOPED IN THE
VALLEYS IN AREAS WHERE THE HIGH CLOUDS HAD CLEARED OUT. ISOLATED
THUNDERSTORMS EAST OF LYNCHBURG WILL NOT IMPACT TAF SITES.
LOCATIONS THAT HAVE SOME CLEARING EARLY THIS MORNING MAY HAVE FOG
DEVELOPMENT...ESPECIALLY IN THE VALLEYS WEST OF THE BLUE RIDGE.
HIGHEST CONFIDENCE OF FOG FORMING IS AT KBCB WERE THE DEW POINT
DEPRESSION WAS ALREADY SMALL. FOG WILL BRING THE VISIBILITY DOWN
TO IFR VALUES...POSSIBLY LIFR AT KLWB AFTER 10Z/6AM.
ANY FOG AND LOW STRATUS DISSIPATES BY 13Z OR SO...FOR WIDESPREAD
VFR CONDITIONS FOR THE DAY SATURDAY...WITH LIGHT EAST TO NORTHEAST
WINDS AS SFC HIGH PRESSURE REMAINS TO THE NORTH AND WEAK SFC
TROUGH WILL LINGER ACROSS NORTH CAROLINA. THIS MAY RESULT IN
ENOUGH WEAK CONVERGENCE AND UPSLOPE TO KICK OFF A FEW ISOLD SHWRS
OR TSTORMS BY AFTERNOON...ESPECIALLY NEAR BLUE RIDGE ALONG OR
SOUTH OF VA/NC BORDER...BUT VERY UNLIKELY ANY ONE SHOWER OR STORM
WILL IMPACT ANY AIRPORTS.
EXTENDED AVIATION...
A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION SUNDAY WITH
A WARM FRONT BRINGING WIDESPREAD MVFR/IFR CONDITIONS IN RAIN
INTO SUNDAY NIGHT.
THIS WILL BE FOLLOWED BY ANOTHER COLD FRONT MONDAY. THIS IS LIKELY
TO KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS
THE REGION.
VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH
PRESSURE BUILDING IN BEHIND THE FRONT WITH A DRIER AIRMASS.
THEN THE NEXT CHANCE OF MVFR CONDITIONS AND PRECIPITATION WILL BE
IN THE MOUNTAINS ON WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...JH/PH/SK
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...AMS/SK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
411 AM CDT SAT APR 18 2015
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 407 AM CDT SAT APR 18 2015
AFTER FURTHER COORDINATION WITH ARX AND THE DNR...WILL ISSUE A RED
FLAG WARNING FOR WOOD COUNTY. THE COMBO OF HUMIDITIES FALLING NEAR
20 PCT THIS AFTERNOON...MAX TEMPS IN THE 60S...WIND SPEEDS OF 10
TO 20 MPH...AND DRY FUELS WILL LEAD TO A CRITICAL FIRE WEATHER DAY
THERE. THIS RED FLAG WARNING WILL TARGET THE PINE COUNTRY OF
CENTRAL WISCONSIN.
ADDITIONALLY...THE COLD FRONT HAS JUST PASSED OVER GREEN BAY.
WINDS HAVE SHIFTED TO THE NORTH AND ARE GUSTING TO 22 KNOTS AT THE
GRB AIRPORT. SOME GUSTS UP TO 25 KNOTS OVER THE BAY ARE ALSO OCCURRING.
&&
.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY
POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE
CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH
IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS
OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN
EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME
GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO
SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS
ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE
WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY.
TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF
NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY
MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY
DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY.
THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY
AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO
THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS
AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE
TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL
WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED
SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A
FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD
HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS
IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES
UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM
WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND
LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND
CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL
HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT
OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS.
LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST.
SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE
WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO
WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW
SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL
IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF
LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW
LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE
AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT
BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST
WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE
WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO
LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO
WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN
GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN
CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK.
THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A
CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS.
RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE
SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL
BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY
POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT
LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF
SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF
WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION.
MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL
RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE
IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME
OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD
TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND
WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN
THE FORECAST.
AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW
AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING
CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING
OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF
SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY
THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1100 PM CDT FRI APR 17 2015
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. A DRY COLD FRONT
WILL ARRIVE LATER TONIGHT. WINDS WILL SHIFT TO THE NORTHEAST BEHIND
THE FRONT...AND BECOME GUSTY FOR A FEW HOURS TODAY...ESPECIALLY IN
EASTERN WISCONSIN. WINDS WILL DIE DOWN AGAIN SATURDAY EVENING WITH
THICKENING MID CLOUDS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM CDT THIS
EVENING FOR WIZ035.
&&
$$
UPDATE.........MPC
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......KURIMSKI
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY
POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE
CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH
IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS
OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN
EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME
GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO
SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS
ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE
WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY.
TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF
NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY
MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY
DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY.
THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY
AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO
THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS
AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE
TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL
WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED
SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A
FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD
HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS
IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES
UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM
WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND
LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND
CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL
HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT
OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS.
LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST.
SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE
WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO
WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW
SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL
IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF
LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW
LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE
AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT
BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST
WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE
WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO
LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO
WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN
GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN
CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK.
THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A
CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS.
RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE
SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL
BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY
POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT
LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF
SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF
WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION.
MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL
RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE
IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME
OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD
TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND
WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN
THE FORECAST.
AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW
AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING
CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING
OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF
SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY
THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1100 PM CDT FRI APR 17 2015
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. A DRY COLD FRONT
WILL ARRIVE LATER TONIGHT. WINDS WILL SHIFT TO THE NORTHEAST BEHIND
THE FRONT...AND BECOME GUSTY FOR A FEW HOURS TODAY...ESPECIALLY IN
EASTERN WISCONSIN. WINDS WILL DIE DOWN AGAIN SATURDAY EVENING WITH
THICKENING MID CLOUDS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......KURIMSKI
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
512 AM MDT SAT APR 18 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 512 AM MDT SAT APR 18 2015
UPPER LOW NEAR WALSENBURG AT THIS TIME TRACKING SLOWLY EAST. DRY
SLOT HAS CURLED AROUND ACROSS MOST OF EASTERN COLORADO WITH
MOISTURE WRAPPING BACK FROM WYOMING INTO THE COLORADO MOUNTAINS.
AT THIS TIME THE BACK PART OF THIS SYSTEM DOES NOT HAVE STRONG
LIFT WITH IT...BUT THIS IS EXPECTED TO INCREASE DURING THE DAY AS
EVERYTHING CONTINUES TO SPIN AROUND THE LOW CENTER MOVING SLOWLY
EAST. A COMPLEX PATTERN...BUT THE GOOD NEWS IS THE MODELS HAVE
PRETTY GOOD AGREEMENT ON THE BIG PICTURE. DETAILS OF JUST WHERE
THE BANDING STRUCTURE AND CONVECTION ARE VARY CONSIDERABLY. LIKING
THE HRRR PRESENTATION OF THE DEVELOPING BACK EDGE SNOW BAND ACROSS
THE MOUNTAINS...ROUGHLY FROM LARAMIE TOWARD RIFLE THIS MORNING.
HARD TO SAY IF THE NORTH CENTRAL MOUNTAINS WILL BE IN THE BEST OF
THIS...OR IF IT WILL STAY FURTHER WEST WITH THE DRIER AIR CURLING
BACK OVER THE FRONT RANGE. I DID INCREASE THE POPS FOR THE
MOUNTAINS...HELD OFF ON INCREASING AMOUNTS TOO MUCH AS THE SNOW
MAY TEND TOWARD LIGHT SHOWERS IN THE VALLEYS WITH A STEADY
BACKGROUND OF LIGHT OROGRAPHIC SNOW. IF THAT BAND WOBBLES FURTHER
EAST AN ADVISORY MAY BE NEEDED. MEANWHILE ON THE PLAINS THERE IS
DRIER AIR ALOFT...BUT THE LOW LEVELS REMAIN MOIST AND THE COLD
POOL ALOFT WILL BE OVER THIS AREA...AND THERE WILL BE SOME LIFT
FROM THE TIP OF THE WARM ADVECTION NEAR THE LOW CENTER. CONVECTION
SHOULD INCREASE THROUGH THE DAY. NOT AS MUCH OF A THUNDERSTORM
RISK TODAY...CAPES LIKELY AROUND 300 J/KG AROUND DENVER AND 600
NEAR THE EASTERN BORDER. I WOULD SAY NEGLIGIBLE SEVERE THREAT
EXCEPT FOR THE COLD TEMPERATURES...COULD BE SOME HAIL OUT EAST BUT
IT SHOULD BE HARD TO GET LARGE HAIL.
FOR TONIGHT THE BACK EDGE BAND WILL TRANSLATE ACROSS OUR AREA AS
THE LOW MOVES EAST. THIS SHOULD BRING A BETTER CHANCE OF
SHOWERS. NORTH WINDS ALSO INCREASING...WHICH COULD WARM/DRY AREAS
NORTH OF DENVER BUT ENHANCE THE THREAT OF SNOW SOUTH OF DENVER.
THE NORTH WIND SHOULD ALSO BRING A FEW DEGREES OF
COOLING...LOWERING SNOW LEVELS BACK DOWN TO 5-6 THOUSAND FEET.
HOWEVER AIR TEMPERATURES WILL STILL BE ABOVE FREEZING IN MOST
AREAS...SO STILL EXPECTING LITTLE IMPACT FOR THE METRO AREA.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 512 AM MDT SAT APR 18 2015
THERE IS WEAK TO MODERATE NORTHWESTERLY JET LEVEL FLOW OVER THE
CWA SUNDAY THROUGH MONDAY NIGHT. THERE IS WEAK DOWNWARD SYNOPTIC
SCALE ENERGY FOR THE CWA SUNDAY...THEN BENIGN ENERGY SUNDAY NIGHT
THROUGH MONDAY NIGHT. THERE IS NORTHERLY FLOW IN THE LOWER LEVELS
ON SUNDAY...WITH WEAKER NORTHEASTERLIES SUNDAY NIGHT. BOUNDARY
LAYER WINDS ARE NORTHWESTERLY ON MONDAY...THEN A HINT AT NORMAL
DRAINAGE PATTERNS MONDAY NIGHT. FOR MOISTURE...THERE IS PLENTY FOR
THE CWA SUNDAY AND SUNDAY NIGHT...THE NAM BEING THE DRIEST. THERE
IS QUITE A BIT OF MOISTURE STILL AROUND BOTH MONDAY AND MONDAY
NIGHT...THE GFS BEING THE WETTEST. THERE IS A BIT OF CAPE OVER THE
FAR SOUTHWEST FORECAST AREA LATE DAY SUNDAY DAY. THERE IS A BIT
MORE CAPE OVER ALL THE HIGH COUNTRY LATE DAY MONDAY...BUT STILL
PRETTY MEAGER AMOUNTS. THE QPF FIELDS HAVE SOME MEASURABLE
PRECIPITATION MOSTLY OVER THE WESTERN TWO-THIRDS OF THE CWA
SUNDAY AFTERNOON INTO MONDAY EVENING. FOR POPS...20-50%S ARE GOOD
SUNDAY INTO MONDAY...THE LOWER NUMBERS FOR THE PLAINS. FOR
TEMPERATURES...SUNDAY`S HIGHS ARE A BIT COLDER THAN TODAY`S BEHIND
THE COLD FRONT LATE TONIGHT...EARLY SUNDAY MORNING. MONDAY`S HIGHS
ONLY WARM UP 1-2 C FROM SUNDAY`S. FOR THE LATER DAYS...TUESDAY
THROUGH FRIDAY...THERE IS AN UPPER RIDGE TUESDAY THROUGH THURSDAY
NOW ON THE MODELS. THE NEXT UPPER TROUGH LOOKS WEAKER THAN IT DID
ON YESTERDAY`S 00Z RUNS AND IT COMES THROUGH THURSDAY NIGHT AND
FRIDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 512 AM MDT SAT APR 18 2015
CONDITIONS WILL BE VARIABLE TODAY AS THERE WILL BE SCATTERED
SHOWERS. FOR THE MORNING THERE WILL BE AREAS OF MVFR CEILINGS WITH
A FEW PATCHES OF IFR. CEILINGS SHOULD BE HIGHER BY LATE
MORNING...BUT STILL EXPECT LOCALIZED MVFR NEAR SHOWERS. THERE MAY
BE LOWER CONDITIONS AGAIN THIS EVENING WHEN THERE IS A BETTER
CHANCE OF SHOWERS...MAINLY MVFR BUT A SLIGHT CHANCE OF IFR
CONDITIONS. WINDS WILL BE LIGHT AND MAINLY FROM THE NORTH OR
NORTHWEST...BUT WITH SOME VARIABILITY. SNOW MAY MIX WITH THE RAIN
TONIGHT...BUT NO RUNWAY ACCUMULATION IS EXPECTED AT THE DENVER
AREA AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GIMMESTAD
LONG TERM...RJK
AVIATION...GIMMESTAD
AREA FORECAST DISCUSSION
NWS ALBANY NY
1110 AM EDT SAT APR 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION TODAY...HOWEVER ITS
ASSOCIATED MOISTURE IS RATHER LIMITED SO MAINLY ONLY AN INCREASE
IN CLOUDS IS EXPECTED. IN ITS WAKE...WINDS WILL BECOME BREEZY FOR
SEVERAL HOURS. HIGH PRESSURE WILL BUILD IN TONIGHT AND SUNDAY
RESULTING IN FAIR AND DRY WEATHER. A SERIES OF WEATHER SYSTEMS
WILL IMPACT THE REGION NEXT WEEK RESULTING IN COOL...DAMP...AND
UNSETTLED CONDITIONS. A WIDESPREAD RAINFALL IS EXPECTED MONDAY
AND MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
MORNING FOG BURNED OFF QUICKLY. A SHORT WAVE TROUGH AND ITS
ASSOCIATED LOW PRESSURE SYSTEM WILL PASS JUST TO OUR NORTHEAST
AND MOVE ACROSS NEW ENGLAND TODAY. MOISTURE REMAINS RATHER LIMITED
WITH THIS SYSTEM. LATEST HRRR ONLY INDICATES SCATTERED CONVECTION
SHOULD REMAINING MAINLY TO OUR NORTH AND EAST. THE BEST POTENTIAL
FOR SOME BRIEF SHOWER WILL BE NORTH OF ALBANY AND INTO THE
SOUTHERN GREENS OF VERMONT.
THE MAIN ISSUE FOR THE DAY IS BREEZY WESTERLY WINDS DEVELOPING
FOR THE AFTERNOON. MOMENTUM TRANSFER OF THE HIGHER MAGNITUDE
WINDS SUGGEST WE TAP INTO H700 LAYER WHERE 30+KTS RESIDES...SO
EXPECTING GUSTS OF 25 TO 35 MPH.
AS FOR TEMPERATURES...GIVEN THE DEEP MIXING EXPECTED AND CURRENT
TEMPERATURES RUNNING A COUPLE DEGREES WARMER...GUIDANCE AND DRY
ADIABATIC DECENT OF THOSE PARCELS ALONG WITH FAVORED LOCATIONS FOR
DOWNSLOPING WOULD YIELD TEMPERATURES AT 70F OR LOWER 70S FOR
VALLEY LOCATIONS AND 50S FOR THE HIGHER TERRAIN.
TONIGHT...SUBSIDENCE ALONG WITH DRIER AIR ALOFT AND SURFACE HIGH
BUILDING INTO THE REGION WILL RESULT IN DIMINISHING WINDS AND ANY
RESIDUAL CLOUD COVER. SO A CLEAR NIGHT EXPECTED WITH LOWS RANGING
FROM THE UPPER 20S ACROSS THE DACKS TO AROUND 40F ALONG THE HUDSON
RIVER FROM ALBANY AND POINT SOUTHWARD.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
GEN MODEL SUITE AGREEMENT HERE WITH SOME SPREAD TWRD THE END OF
THE PERIOD...MAINLY ON QPF AMNTS.
SUNDAY BEGINS WITH 500HPA RIDGE AXIS FM DELMARVA TO LK HURON...AND
SFC HIGH RIDGING S FM QB. RESULT WILL BE WIDESPREAD SUBSIDENCE...LOW
RH...LIGHT WINDS AND BRILLIANT SUNSHINE. SUN EVNG THE 500HPA RIDGE
WILL SLIDE OFFSHORE ALONG WITH THE SFC HIGH. OVERNIGHT EVOLVING
UPR GRT PLAINS 500HPA CUT OFF SHIFTS E...SHARPENING THE TROF/RIDGE
AMPLITUDE AND SHORTING THE WAVELENGTH AND UVM. SFC CYCLOGEN
ENSUES IN THE W OHIO VLY AND LIFTS NE INTO THE S GRTLKS MON. WMFNT
TRAILS SE FM MI-VA CAPES...AND LIFTS TWRD RGN SUN NT AS SFC LOW
ORGANIZES ON THE COAST. RESULT WILL BE RAPIDLY INCRG LLVL SFC WIND
GRAD...INCRG LLVL JETS...AND MOISTURE INFLUX INTO RGN. SHRA WILL
DEVELOP OVERNIGHT SUN AND EVOLVE INTO A WIDESPREAD RAIN INTO MON.
THE 500HPA CUT OFF OVER THE GRT PLAINS MOVES LITTLE BY TUES ONLY
REACHING LK SUPERIOR. WITH THE SFC LOW OVER ONTARIO...THE FRONTAL
STRUCTURE HAS EVOLVED INTO AN OCCLUSION FM OTTAWA VLY TO CSTL LOW
OVER S NEW ENG TUE MRNG. ONCE THE OCCLUSION CLEARS THE AREA...DRY
SLOT WRAPS ACROSS REGION WITH GENERALLY IMPVG CONDS. ALTHOUGH
THERE IS SOME SPREAD IN THE MODELS ON THE TIMING..ALL HAVE DONE SO
BY 18UTC TUES. AS 500HPA SHORT WVS ARE IN ROTATION AROUND BASE OF
CUTOFF TO OUR NW...SCT -SHRA MAY STILL OCCURRING IN STEEPENING
LAPSE RATE OVER FCA.
TEMPS WILL BE NR TO SLIGHTLY BLO NORMALS DURING THIS PERIOD WITH
HIGHS IN THE UPPER 50S TO MID 60S SUNDAY...AND MAINLY IN THE 50S
AFTERWARDS. LOWS WILL BE IN THE 30S WITH 40S TUESDAY MORNING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
THIS PERIOD WILL BE DOMINATED BY A LARGE VERTICAL LOW PRESSURE
SYSTEM CENTERED OVER ONTARIO...BUT IMPACTING MUCH OF EASTERN HALF
OF CANADA AND NE USA.
WHILE THE MODELS DIFFER IN TIMING AND PLACEMENT OF THE FEATURES...THE
MAIN STORY WILL BE 500HPA SHORT WVS ROTATING AROUND THE LARGE
CUTOFF...EACH DRAGGING A SFC FRONT/BOUNDARY THROUGH THE FCA.
THESE FEATURES WILL PRODUCE VRBL CLOUDS...AND TRIGGER SCT TO AT
TIMES BKN -SHRA... MAYBE SOME -SHSN AT HIR TRRN...HWVR THE
ACTIVITY WILL BE DIURNALLY MODULATED AS STRONG APRIL SUN...AND
STEEP LAPSE RATES WILL ENHANCE THE CONVECTIVE NATURE OF THE SYSTEM
AN MAY EVEN RESULT IN SOME SMALL HAIL.
AS ITS OFTEN WITH THESE EVENTS...WHEN FCA IS ON SE QUADRANT OF A
MAJOR CUT OFF SYSTEM...THEY TEND TO OVER DO THE DISMAL CONDITIONS
CLOUDS AND SHOWERS.
FCST PERIOD WILL FEATURE BLO NORMAL TEMPS WITH HIGHS MAINLY
50S...LOWS IN THE 30S...VRBLE CLOUDS...SCT -SHRA/-SHSN. THESE WILL
BE DRIVEN...DIURNALLY...WITH PASSING 500HPA SHORT WVS AND BY CDFNTS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
APPEARS IFR CONDITIONS EVOLVED AT KGFL-KPSF OVERNIGHT WHERE DEWPOINT
DEPRESSIONS QUICKLY COLLAPSED. THIS FOG SHOULD BE RATHER SHALLOW IN
NATURE AND QUICKLY DISSIPATE WITH SUNRISE.
DURING THE DAY...FRONTAL BOUNDARY WILL QUICKLY MOVE ACROSS THE
REGION. WHILE MOISTURE REMAINS LIMITED WITH THIS SYSTEM...SOME SCT-
BKN VFR CIGS ARE EXPECTED MAINLY AFFECTING KGFL-KPSF.
OTHERWISE...WESTERLY WINDS WILL INCREASE WITH GUSTS OVER
20KTS...THEN WINDS SHIFTS TO THE NORTHWEST WITH EVEN SOME HIGHER
GUSTS AROUND 25KTS.
THE WINDS AND SKIES WILL ALL DISSIPATE THIS EVENING AS HIGH PRESSURE
SETTLES ACROSS THE ENTIRE REGION WITH VFR CONDITIONS EXPECTED.
OUTLOOK...
SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. BREEZY. LIKELY RA.
MONDAY: HIGH OPERATIONAL IMPACT. BREEZY. DEFINITE RA.
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
RED FLAG WARNING FOR ALL OF EASTERN NEW YORK...BERKSHIRES AND
NORTHWEST CONNECTICUT LATER TODAY...
GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR SOUTHERN VERMONT...
EXTENSIVE COORDINATION OVERNIGHT ALONG WITH FORECAST METEOROLOGICAL
CONDITIONS HAVE WARRANTED THE UPGRADE TO RED FLAG WARNINGS FOR
EASTERN NEW YORK...BERKSHIRES AND NORTHWEST CONNECTICUT. WE WILL
HIGHLIGHT THE LOW RELATIVE HUMIDITIES...SNOW COVERAGE INTO THE
HIGHER TERRAIN...AND GUSTY WINDS WITH A SPECIAL WEATHER STATEMENT
/SPS/ FOR SOUTHERN VERMONT.
COMPACT WAVE TO THE NORTH OF THE GREAT LAKES WILL TRACK EAST-
SOUTHEAST TODAY. MOISTURE ASSOCIATED WITH THIS SYSTEM REMAINS
LIMITED...HOWEVER...ISOLATED SHOWERS ARE POSSIBLE MAINLY TO THE
NORTH OF ALBANY AND INTO SOUTHERN VT AND PERHAPS TOUCHING NORTHERN
BERKSHIRES. THEREAFTER...DEEP MIXING WITH INCREASING WINDS AND
DROPPING RELATIVE HUMIDITY VALUES YIELDS A COMBINATION OF FIRE
WEATHER HAZARDS TODAY. THE MAIN IMPACT POTENTIAL WILL BE DURING THE
AFTERNOON HOURS.
FOR SOUTHERN VERMONT...INCREASE IN CLOUD COVER ALONG WITH MARGINAL
LEVELS FOR FIRE WEATHER...SNOW COVER ACROSS THE HIGHER TERRAIN AND
COORDINATION WITH OFFICIALS HAVE RESULTED IN A SPECIAL WEATHER
STATEMENT /SPS/.
TONIGHT...WINDS WILL SUBSIDE ALONG WITH A SLOW RECOVERY OF THE
RELATIVE HUMIDITY VALUES AS A SURFACE HIGH BUILDS INTO THE REGION.
THIS HIGH REMAINS IN CONTROL THROUGH SUNDAY WITH LIGHT WINDS YET DRY
CONDITIONS WITH MINIMUM RELATIVE HUMIDITY VALUES RANGING BETWEEN 20-
30 PERCENT.
&&
.HYDROLOGY...
NO HYDROLOGY ISSUES EXPECTED THROUGH THE MONDAY MORNING AS CONDITIONS
WILL BE MAINLY DRY EXCEPT ISOLD -SHRA N TIER MIDDAY TODAY WITH A
CFP. A WIDESPREAD SOAKING RAINFALL IS LIKELY LATE SUNDAY NIGHT
INTO TUESDAY W/QPF ON THE ORDER OF HALF AN INCH TO AN INCH.
THE NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC)
INDICATES THAT THERE IS STILL A FEW INCHES OF WATER EQUIVALENT IN
THE SNOW PACK ACROSS THE SRN ADIRONDACKS AND NORTHEASTERN
BERKSHIRE COUNTY. PORTIONS OF THE SOUTHERN GREEN MOUNTAINS STILL
HAVE 4 TO 9 INCHES OF SNOW WATER EQUIVALENT.
THE GENERAL CONSENSUS IS FOR AROUND AN ONE INCH OF RAINFALL AT
THIS TIME WITH THE HIGHER TOTALS SOUTH OF THE CAPITAL DISTRICT.
THIS RAINFALL COMBINED WITH RISES FROM ONGOING SNOWMELT NORTH...MAY
RESULT IN WITHIN BANK RISES MONDAY AND TUESDAY.
FOR DETAILS ON SPECIFIC AREA RIVER AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB-
SITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013.
NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025.
VT...NONE.
&&
$$
SYNOPSIS...IAA/SNYDER
NEAR TERM...IAA/BGM/NAS/WASULA
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...BGM/NAS
FIRE WEATHER...IRL/WASULA
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS WICHITA KS
1039 AM CDT SAT APR 18 2015
.SYNOPSIS...
ISSUED AT 350 AM CDT SAT APR 18 2015
THE UPPER LOW HAS SHIFTED EASTWARD AND IS SPINNING OVER COLORADO.
SMALL PIECES OF ENERGY WITH IT HAVE HELPED TO SPARK OFF SHOWERS
AND THUNDERSTORMS OVER THE PLAINS STATES DURING THE OVERNIGHT
HOURS. EXPECT CENTRAL AND EASTERN KANSAS TO SEE SHOWERS AND
THUNDERSTORMS THROUGH MUCH OF THE MORNING.
BILLINGS WRIGHT
&&
.UPDATE...
ISSUED AT 1037 AM CDT SAT APR 18 2015
MAIN UPPER LEVEL LOW OVER THE CO ROCKIES IS BEGINNING TO MAKE SLOW
PROGRESS INTO THE PLAINS THIS MORNING. DIFFLUENT SW FLOW AHEAD OF
THIS UPPER LOW HAS LED TO ANOTHER ROUND OF SHOWERS AND EMBEDDED
STORMS OVER THE ERN HALF OF KS. EXPECT THE SHOWERS IN ERN KS TO
GRADUALLY SHIFT TO THE E-NE OF THE AREA LATE THIS MORNING. BUT
ATTENTION QUICKLY SHIFTS BACK TO THE WEST...AS THIS UPPER LOW BEGINS
TO PUSH EAST INTO WRN KS. ALREADY SEEING SOME CLEARING ACROSS THE
WESTERN HALF OF THE FORECAST AREA...WHICH WILL LEAD TO INCREASED
SURFACE HEATING INTO THE AFTERNOON HOURS. SETUP IS A LITTLE
DIFFERENT THAN YESTERDAY...AS DRYLINE IN SW KS IS ON THE MOVE TO THE
EAST THIS MORNING...CURRENTLY JUST TO THE WEST OF THE KDDC.
LATEST LOOK AT THE HI-RES SHORT TERM MODELS SUGGEST THAT THE
INCREASED HEATING BETWEEN THE DRYLINE AND WRN SECTIONS OF THE
FORECAST AREA WILL HELP DESTABILIZE THE ATMOSPHERE JUST TO THE WEST
OF THE FORECAST AREA THIS AFTERNOON. THIS AREA IS ALSO WEAKLY
CAPPED. SO BETTER HEATING THIS MORNING...AND NOT ALOT OF RECOVERY
TIME NEEDED...MAY LEAD TO CONVECTION DEVELOPING EARLIER THAN
YESTERDAY. ESPECIALLY JUST AHEAD OF THE DRYLINE AS IT PUSHES EAST OF
KDDC...AND PUSHES TO JUST WEST OF KPPT. SO MAY SEE CONVECTION
DEVELOP AND MOVE INTO WRN SECTIONS OF THE FORECAST AREA (WEST OF I-
135) BETWEEN 20-22Z. LATEST HRRR AND ARW SUGGEST THIS SCENARIO.
AS FAR AS SEVERE WEATHER CHANCES...BULK SHEAR AROUND 40 KTS AND
SBCAPE VALUES EXPECTED TO BE IN THE 2000-2500 J/KG SUGGEST A STRONG
TO SEVERE CHANCE WITH A MIXED MODE WITH MULTICELL CLUSTERS AND A FEW
LOW TOPPED SUPERCELLS WITH LARGE HAIL (QUARTER TO GOLFBALL) AND
DAMAGING WINDS THE MAIN CONCERN. CANNOT RULE OUT A WEAK/BRIEF
TORNADO OR TWO...GIVEN THE DIRECTIONAL SHEAR AND INCREASED VERTICAL
STRETCHING DUE TO THE STEEP LAPSE RATES.
KETCHAM
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 350 AM CDT SAT APR 18 2015
MORNING:
EXPECT THE SHOWERS AND THUNDERSTORMS CURRENTLY ONGOING TO CONTINUE
TO DEVELOP AND SHIFT EAST-NORTHEASTWARD DURING THE MORNING HOURS.
DO NOT EXPECT THESE TO BE STRONG OR SEVERE...JUST A WELCOME DRINK
OF RAIN.
THIS AFTERNOON/EVENING:
THINK THAT THERE MAY BE SOME CLEARING ACROSS WESTERN AREAS THIS
MORNING/EARLY AFTERNOON BEFORE THUNDERSTORMS FIRE AGAIN THIS
AFTERNOON ALONG AND AHEAD OF THE DRYLINE. STILL SLIGHTLY CONCERNED
THAT STORMS COULD FIRE EARLIER IN THE AFTERNOON...CLOSER TO 18Z
WITH THE SUPPORT FROM THE UPPER DYNAMICS OF THE UPPER
LOW...HOWEVER...THE BEST SUPPORT FOR COVERAGE IS CLOSER TO 21Z TO
00Z. EXPECT THESE STORMS TO IMPACT CENTRAL AND SOUTH CENTRAL
KANSAS WHERE INSTABILITY AND SHEAR PARAMETERS ARE PLENTIFUL TO
SUPPORT SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WIND. THERE
IS STILL A SMALL CHANCE FOR A TORNADO...BEST CHANCES RESIDE IN
SOUTH CENTRAL KANSAS AND CLOSER TO THE OKLAHOMA BORDER WITH THE
BETTER HELICITY/EHI FURTHER SOUTH IN OKLAHOMA. EXPECT STORMS TO
MOVE EASTWARD DURING THE EVENING. THE SEVERE CHANCES DECREASE
OVER SOUTHEAST KANSAS THOUGH AS THE PARAMETERS ARE LESS FAVORABLE
THERE TO SUPPORT SEVERE STORMS.
DURING THE OVERNIGHT HOURS SATURDAY INTO SUNDAY:
THE UPPER LOW WILL CONTINUE TO PUSH EASTWARD AND LOBES OF
VORTICITY ARE EXPECTED TO CIRCLE AROUND IT WHICH COULD SPARK
MULTIPLE ROUNDS OF SHOWERS/THUNDERSTORMS OVER SOUTHERN KANSAS. THE
UPPER LOW WILL TRAVERSE THE STATE SUNDAY...THUNDERSTORMS WILL
BECOME SHOWERS AND THE FOCUS WILL SHIFT TO EAST AND SOUTHEAST
KANSAS. A COLD FRONT ASSOCIATED WITH THE UPPER LOW WILL MOVE
ACROSS THE STATE AND SHIFT WINDS TO THE NORTHWEST AND GUSTY.
TEMPERATURES WILL BE COOLER ON MONDAY...IN THE 60S BUT THINGS
SHOULD BE DRY AS THE UPPER LOW SLOWLY BEGINS TO SHIFT
NORTHEASTWARD.
BILLINGS WRIGHT
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT APR 18 2015
THE MAIN UPPER LOW IS SLOW TO EXIT AND A PIECE OF ENERGY ROTATING
AROUND ITS BACK SIDE IT WILL IMPACT THE AREA WHILE THE CENTRAL
PLAINS SITS UNDER NORTHWESTERLY UPPER LEVEL FLOW. PRECIPITATION
CHANCES WILL BE POSSIBLE EARLY TUESDAY AND THROUGHOUT THE
DAY...BUT THE GUIDANCE HAS DISCREPANCIES AMONGST THE LOCATION OF
THE PRECIPITATION...THINK IT COULD BE SOUTH OF THE STATE
LINE...HOWEVER THE GFS PUSHES IT RIGHT OVER CENTRAL KANSAS.
CONFIDENCE ON THIS PERIOD AND PRECIPITATION CHANCES IS LOW.
BY WEDNESDAY THROUGH FRIDAY THE UPPER LOW MOVES OFF TO THE
NORTHEAST AND ANOTHER SYSTEM MOVES IN FROM THE SOUTHWEST.
PRECIPITATION AND POSSIBLY THUNDERSTORM CHANCES INCREASE BY
WEDNESDAY THROUGH FRIDAY ACROSS THE AREA. THIS PERIOD HAS QUITE A
FEW DISCREPANCIES WITH THE VARIOUS SOLUTIONS...CONFIDENCE ON ANY
SOLUTION IS LOW.
TEMPERATURES WILL STAY IN THE UPPER 60S AND LOW 70S...NEAR
SEASONAL NORMALS.
BILLINGS WRIGHT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 653 AM CDT SAT APR 18 2015
TOUGH AVIATION FORECAST. CONFIDENCE ONCE AGAIN NOT PARTICULARLY
HIGH GIVEN CHALLENGES OF WEAKLY CAPPED/WEAK SURFACE CONVERGENCE
PATTERN. STORMS WILL PERSIST FOR A FEW HOURS AT KCNU...WHILE
REMAINDER OF THE AREA MORE THAN LIKELY DRY DURING THE MORNING.
UPPER LOW HAS DRIFTED A BIT CLOSER...SO ONSET OF RENEWED
CONVECTION MAY BE A BIT QUICKER THAN YESTERDAY...BUT STILL
THINKING LATER IN THE AFTERNOON IN AT KRSL/KHUT...WITH KICT/KSLN
VERY LATE AFTERNOON/EVENING AND KCNU LATER TONIGHT. -HOWERTON
&&
.FIRE WEATHER...
ISSUED AT 350 AM CDT SAT APR 18 2015
FIRE WEATHER CONCERNS REMAIN LOW WITH THE UPPER LEVEL SYSTEM
IMPACTING THE AREA CAUSING MULTIPLE ROUNDS OF PRECIPITATION.
THE GRASSLAND FIRE DANGER INDEX REMAINS BELOW ELEVATED CONCERN
LEVELS.
BILLINGS WRIGHT
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 75 54 66 39 / 50 60 70 10
HUTCHINSON 75 52 62 39 / 50 60 70 10
NEWTON 73 52 62 40 / 50 60 80 10
ELDORADO 74 54 69 41 / 40 60 80 10
WINFIELD-KWLD 74 54 70 40 / 40 60 70 10
RUSSELL 75 51 59 36 / 50 60 60 10
GREAT BEND 74 50 59 35 / 50 60 60 10
SALINA 76 52 61 38 / 50 60 70 10
MCPHERSON 74 52 60 38 / 50 60 70 10
COFFEYVILLE 73 56 70 43 / 80 60 80 20
CHANUTE 72 56 70 42 / 80 60 80 20
IOLA 71 56 69 42 / 80 60 80 20
PARSONS-KPPF 73 56 69 42 / 80 60 80 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
629 AM CDT Sat Apr 18 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT SAT APR 18 2015
Showers and thunderstorms developing this hour across northeast
Oklahoma into south central and north central Kansas, with cell
movement toward the north northwest and the cluster moving more
northerly. This area is forecast to move across the forecast area
through the morning hours today.
Struggle with the forecast continues to be timing and coverage of
precipitation chances. After initial energy lifts across Eastern
Kansas through early afternoon, next uncertainty will be for chances
later in the afternoon. HRRR develops a cluster of showers in south
central KS, but would anticipate a break between the systems with
subsidence behind the main wave inhibiting convective development.
Have higher chances in the morning, with lower chances middle
afternoon, followed by an increase from west to east through the
evening into the overnight hours as the main wave finally starts to
get an easterly push, from both a northern US shortwave and an upper
jet traversing the southern states. With a lull in precipitation
and possibly some better sunshine out west, this would boost
instability and chances for severe thunderstorms as late day storms
develop along the dryline to our west and along the northward
advancing warm front. Primary threat would be hail, but closer
proximity to these surface features in north central Kansas could
bring an isolated tornado risk there. General precipitation chances
continue in the overnight hours ahead of the upper low as it
continues to slowly move east. Highs for Saturday in the middle 70s
west to near 70 east, with lows in the 50s.
.LONG TERM...(Sunday through Friday)
Issued at 342 AM CDT SAT APR 18 2015
By Sunday morning the mid/upper low will be centered over SC KS and
NC OK as it progresses eastward. During this time the low will
become more of an open wave as another shortwave digs into the
northern plains and upper Midwest. These waves will bring a cold
front through the region during the day Sunday. In the morning the
better chance for showers and some thunder should be in southern KS
where the front and mid level low are more coupled in the vertical.
By 18Z the models are hinting at an increase of instability on the
order of about 1000 j/kg ahead of the front that should stretch
across eastern KS. Lapse rates are not overly impressive, and deep
layer shear could reach 30 kts. Although the better shear will be
further southeast over southern MO where the flow aloft is slightly
stronger. Therefore kept a mention of thunderstorms for east central
KS during the afternoon. A majority of the precip should clear the
area around 03Z in the evening.
A sharp pressure gradient behind the front will support northwest
surface winds around 15 to 25 mph with gusts as up to 35 mph
especially in NC KS. Cold air advection on the backside of the wave
drops temps into the lower 40s and upper 30s by Monday morning.
Winds do not completely decouple Sunday night so there is little
concern for frost. On Monday winds remain gusty with high temps
generally around 60 and partly sunny skies. Monday night will not be
the classic set up for frost with a expansive high building
southward, but the winds do decrease and temps are forecast to reach
the mid to upper 30s. Therefore could not rule out the possibility
for frost perhaps in preferred sheltered locations.
NW flow aloft develops over the region as the northern stream wave
deepens over the Great Lakes. The models are beginning to advertise
embedded shortwaves within the NW flow, which track over the plains
around mid week. This will bring small chances for either showers or
thunderstorms. Late in the week a southern wave crashes the southern
CA coast and tracks northeastward towards the center of the country.
There are some differences on how far north the instability reaches
ahead of the system, and there are additional waves in the NW flow
that could interfere with the southern stream system. Confidence in
any solution is low at this point.
&&
.AVIATION...(For the 12Z TAFs through 12Z Sunday Morning)
Issued at 624 AM CDT SAT APR 18 2015
TAFs are generally VFR as first round of rain and isolated thunder
move across the area in the morning. Another round is expected
later this evening as storms develop west of the terminals and
move east. Coverage in between expected to be sporadic and won`t
mention more than VCTS at this time for the afternoon evening
hours.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Sanders
AVIATION...67
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1126 AM EDT SAT APR 18 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 328 AM EDT SAT APR 18 2015
ANOTHER SUNNY DAY IS EXPECTED TODAY WITH HIGHS AROUND 70. LOW
PRESSURE WILL MOVE NORTH FROM THE GULF AREA SUNDAY BRINGING QUITE A
BIT OF RAIN WITH IT. AFTER THE LOW MOVES EAST...COLDER AIR WILL MOVE
OVER LOWER MICHIGAN AND REMAIN IN PLACE NEXT WEEK. HIGHS WILL ONLY
REACH THE MID 40S TO MID 50S NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1055 AM EDT SAT APR 18 2015
I INCREASED THE HIGH TEMPERATURE AROUND 5 DEGREES FOR THIS
AFTERNOON BASED ON MORNING SOUNDING DATA. THE RAP MODEL SEEMS TO
BE DOING A BETTER JOB OF SHOWING CURRENT TEMPERATURES...DEW POINTS
AND WINDS SO I USED THAT TO INCREASE THE WIND SPEED...TEMPERATURES
AND LOWER THE DEW POINTS. THAT ALL BEING SO... WE COULD SEE HIGHS
IN THE MID TO UPPER 70S OVER THE WESTERN SECTIONS OF THE CWA THIS
AFTERNOON. WE WILL BE GETTING CLOSE TO RED FLAG CONDITIONS IF THIS
HAPPENS. FOR NOW I WILL LET OUR HWO AND POST OF FACEBOOK COVER
THIS ISSUE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EDT SAT APR 18 2015
FORECAST CONCERNS DEAL WITH THE LOW APPROACHING SUNDAY. AFTER
ANOTHER SUNNY AND MILD DAY TODAY CLOUDS WILL INCREASE TONIGHT AS A
PHASED NORTHERN/SOUTHERN STREAM LOW APPROACHES FROM THE SOUTH.
STRONG 60KT LLJ WILL DRAW UP ABUNDANT MOISTURE INTO THE SYSTEM.
STRONG ISENTROPIC LIFT LATE SUNDAY MORNING WILL LEAD TO RAPID RAIN
DEVELOPMENT FROM SOUTH TO NORTH. LOOK FOR THE WIND TO INCREASE AS
WELL...AT LEAST UNTIL THE LOW MOVES OVERHEAD SUNDAY EVENING. SHORT
RANGE MODELS HAVE BEEN CONSISTENT MOVING THE LOW DIRECTLY OVER THE
CWA SO CONFIDENCE IS PRETTY HIGH WE/LL SEE RAIN. QPF AROUND 3/4 INCH
LOOKS POSSIBLE AS MIXING RATIOS CLIMB TO 8G/KG BY LATE SUNDAY
AFTERNOON. THERE STILL ISN/T A STRONG SIGNAL FOR THUNDER SO WE KEPT
IT OUT OF THE GRIDS. HOWEVER GIVEN A SLIGHT DECREASE IN STABILITY
NOTED WE CAN/T RULE IT OUT EITHER.
MONDAY WILL BE MUCH COOLER AS THE LOW MOVES EAST AND WEST WINDS
DEVELOP. HIGHS IN THE MID 50S ARE EXPECTED. THE UPPER LOW WILL MOVE
OVER THE CWA MONDAY SO WE/LL CONTINUE TO SEE SCATTERED SHOWERS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EDT SAT APR 18 2015
MOST OF NEXT WEEK WILL BE COLDER THAN NORMAL WITH SCATTERED RAIN OR
MIXED RAIN AND SNOW SHOWERS AS AN UPPER LOW BECOMES PARKED OVER THE
NORTHERN GREAT LAKES REGION. DEEP CYCLONIC FLOW AND COLD ADVECTION
WILL LEAD TO CONSIDERABLE CLOUDINESS WITH HIGHS ONLY IN THE 40S AND
FREQUENTLY BREEZY CONDITIONS.
THE MAIN RISK FOR SNOW SHOWERS WILL BE AT NIGHT AND DURING THE EARLY
MORNING WHEN THE BOUNDARY LAYER IS COOLEST... ESPECIALLY FOR HIGHER
ELEVATIONS NEAR AND NORTH OF ROUTE 10 WHERE SOME LIGHT ACCUMULATIONS
EVEN APPEAR POSSIBLE.
GFS/ECMWF DO NOT LOOK PARTICULARLY BULLISH WITH QPF AT ANY TIME NEXT
WEEK ALTHOUGH SPOKES OF VORTICITY ROTATING AROUND THE UPPER LOW
MAY LEAD TO OCCASIONAL BOUTS OF INCREASED COVERAGE OF HEAVIER
SHOWERS.
THINGS APPEAR TO DRY OUR THURSDAY NIGHT AND FRIDAY WHEN THE UPR LOW
MOVES EAST AND SFC RIDGING ARRIVES FROM THE WEST. BY FRIDAY HIGHS
COULD BE BACK UP INTO THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 745 AM EDT SAT APR 18 2015
SFC WINDS WILL INCREASE OUT OF THE NORTHEAST LATER THIS MORNING...
WITH SPEEDS OF 10 TO 20 KTS BECOMING COMMON BY AFTERNOON. THE
WINDS INCREASE FURTHER AFTER 20Z... WITH SOME GUSTS TO 30 KTS
POSSIBLE LATE TODAY INTO TONIGHT. HIGH CONFIDENCE IN VFR
CIGS/VSBYS CONTINUING TODAY AND TONIGHT.
&&
.MARINE...
ISSUED AT 328 AM EDT SAT APR 18 2015
A COLD FRONT WILL MOVE THROUGH EARLY TODAY AND TURN THE WINDS TO THE
NORTHEAST. THE OFFSHORE FLOW WILL CONTINUE TONIGHT AND STRENGTHEN. A
SCA MAY BE NEEDED TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 1126 AM EDT SAT APR 18 2015
A GOOD SOAKING RAINFALL IS STILL ON TRACK TO AFFECT THE ENTIRE AREA
BEGINNING SUNDAY. THE BULK OF THE MOISTURE WILL LIKELY FALL
BETWEEN SUNDAY AFTERNOON INTO MONDAY MORNING WITH SOME GUIDANCE
HINTING AT OVER AN INCH IN SPOTS. ADDITIONAL CHANCES FOR RAIN WILL
SPAN THROUGH THE MIDDLE OF THE WEEK BUT ARE NOT EXPECTED TO BE
QUITE AS ABUNDANT WITH MOISTURE.
RIVERS WILL MAINLY RESPOND IN THE MANNER OF MINOR RISES. THIS SHOULD
MOSTLY CONSIST OF WITHIN BANK RISES. I HAVE A LITTLE MORE CONFIDENCE
IN THINKING MAPLE RAPIDS COULD FLIRT WITH ADVISORY CRITERIA ONCE AGAIN.
THIS IS PENDING THE AMOUNT OF RAINFALL RECEIVED THROUGH EARLY MONDAY.
OTHERWISE...WE ARE LOOKING PRETTY GOOD WITH THIS NOT BEING A CONVECTIVE
MODE OF PRECIPITATION...NO REAL SURPRISES AT THIS POINT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1056 AM EDT SAT APR 18 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 328 AM EDT SAT APR 18 2015
ANOTHER SUNNY DAY IS EXPECTED TODAY WITH HIGHS AROUND 70. LOW
PRESSURE WILL MOVE NORTH FROM THE GULF AREA SUNDAY BRINGING QUITE A
BIT OF RAIN WITH IT. AFTER THE LOW MOVES EAST...COLDER AIR WILL MOVE
OVER LOWER MICHIGAN AND REMAIN IN PLACE NEXT WEEK. HIGHS WILL ONLY
REACH THE MID 40S TO MID 50S NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1055 AM EDT SAT APR 18 2015
I INCREASED THE HIGH TEMPERATURE AROUND 5 DEGREES FOR THIS
AFTERNOON BASED ON MORNING SOUNDING DATA. THE RAP MODEL SEEMS TO
BE DOING A BETTER JOB OF SHOWING CURRENT TEMPERATURES...DEW POINTS
AND WINDS SO I USED THAT TO INCREASE THE WIND SPEED...TEMPERATURES
AND LOWER THE DEW POINTS. THAT ALL BEING SO... WE COULD SEE HIGHS
IN THE MID TO UPPER 70S OVER THE WESTERN SECTIONS OF THE CWA THIS
AFTERNOON. WE WILL BE GETTING CLOSE TO RED FLAG CONDITIONS IF THIS
HAPPENS. FOR NOW I WILL LET OUR HWO AND POST OF FACEBOOK COVER
THIS ISSUE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EDT SAT APR 18 2015
FORECAST CONCERNS DEAL WITH THE LOW APPROACHING SUNDAY. AFTER
ANOTHER SUNNY AND MILD DAY TODAY CLOUDS WILL INCREASE TONIGHT AS A
PHASED NORTHERN/SOUTHERN STREAM LOW APPROACHES FROM THE SOUTH.
STRONG 60KT LLJ WILL DRAW UP ABUNDANT MOISTURE INTO THE SYSTEM.
STRONG ISENTROPIC LIFT LATE SUNDAY MORNING WILL LEAD TO RAPID RAIN
DEVELOPMENT FROM SOUTH TO NORTH. LOOK FOR THE WIND TO INCREASE AS
WELL...AT LEAST UNTIL THE LOW MOVES OVERHEAD SUNDAY EVENING. SHORT
RANGE MODELS HAVE BEEN CONSISTENT MOVING THE LOW DIRECTLY OVER THE
CWA SO CONFIDENCE IS PRETTY HIGH WE/LL SEE RAIN. QPF AROUND 3/4 INCH
LOOKS POSSIBLE AS MIXING RATIOS CLIMB TO 8G/KG BY LATE SUNDAY
AFTERNOON. THERE STILL ISN/T A STRONG SIGNAL FOR THUNDER SO WE KEPT
IT OUT OF THE GRIDS. HOWEVER GIVEN A SLIGHT DECREASE IN STABILITY
NOTED WE CAN/T RULE IT OUT EITHER.
MONDAY WILL BE MUCH COOLER AS THE LOW MOVES EAST AND WEST WINDS
DEVELOP. HIGHS IN THE MID 50S ARE EXPECTED. THE UPPER LOW WILL MOVE
OVER THE CWA MONDAY SO WE/LL CONTINUE TO SEE SCATTERED SHOWERS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EDT SAT APR 18 2015
MOST OF NEXT WEEK WILL BE COLDER THAN NORMAL WITH SCATTERED RAIN OR
MIXED RAIN AND SNOW SHOWERS AS AN UPPER LOW BECOMES PARKED OVER THE
NORTHERN GREAT LAKES REGION. DEEP CYCLONIC FLOW AND COLD ADVECTION
WILL LEAD TO CONSIDERABLE CLOUDINESS WITH HIGHS ONLY IN THE 40S AND
FREQUENTLY BREEZY CONDITIONS.
THE MAIN RISK FOR SNOW SHOWERS WILL BE AT NIGHT AND DURING THE EARLY
MORNING WHEN THE BOUNDARY LAYER IS COOLEST... ESPECIALLY FOR HIGHER
ELEVATIONS NEAR AND NORTH OF ROUTE 10 WHERE SOME LIGHT ACCUMULATIONS
EVEN APPEAR POSSIBLE.
GFS/ECMWF DO NOT LOOK PARTICULARLY BULLISH WITH QPF AT ANY TIME NEXT
WEEK ALTHOUGH SPOKES OF VORTICITY ROTATING AROUND THE UPPER LOW
MAY LEAD TO OCCASIONAL BOUTS OF INCREASED COVERAGE OF HEAVIER
SHOWERS.
THINGS APPEAR TO DRY OUR THURSDAY NIGHT AND FRIDAY WHEN THE UPR LOW
MOVES EAST AND SFC RIDGING ARRIVES FROM THE WEST. BY FRIDAY HIGHS
COULD BE BACK UP INTO THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 745 AM EDT SAT APR 18 2015
SFC WINDS WILL INCREASE OUT OF THE NORTHEAST LATER THIS MORNING...
WITH SPEEDS OF 10 TO 20 KTS BECOMING COMMON BY AFTERNOON. THE
WINDS INCREASE FURTHER AFTER 20Z... WITH SOME GUSTS TO 30 KTS
POSSIBLE LATE TODAY INTO TONIGHT. HIGH CONFIDENCE IN VFR
CIGS/VSBYS CONTINUING TODAY AND TONIGHT.
&&
.MARINE...
ISSUED AT 328 AM EDT SAT APR 18 2015
A COLD FRONT WILL MOVE THROUGH EARLY TODAY AND TURN THE WINDS TO THE
NORTHEAST. THE OFFSHORE FLOW WILL CONTINUE TONIGHT AND STRENGTHEN. A
SCA MAY BE NEEDED TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 1119 AM EDT FRI APR 17 2015
NO RIVER FLOOD ADVISORIES ARE IN EFFECT AT THIS TIME. IMPROVEMENT
IS EXPECTED TO CONTINUE AS DRY CONDITIONS WILL HOLD STRONG TODAY
THROUGH SATURDAY.
THOUGHTS ON THE NEXT ROUND OF MOISTURE ARE CONSISTENT WITH THE
PREVIOUS HYDRO UPDATE (4/16). A DECENT SOAKING RAIN IS EXPECTED TO
MOVE IN SUNDAY WITH OFF/ON WET WEATHER POSSIBLE THROUGH THE
MIDDLE OF NEXT WEEK. MUCH OF THE MOISTURE SHOULD FALL LATE IN THE
WEEKEND AND EARLY INTO THE NEW WORK WEEK. THIS COULD RESULT IN MINOR
UPTICKS FOR RIVERS. THE LACK OF CONVECTIVE ACTIVITY...OR HIGH END
HEAVIER RAINFALL...KEEPS ME SOMEWHAT CONSERVATIVE ON ANY RISES
THAT WOULD OTHERWISE BE MORE CONCERNING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1025 AM CDT SAT APR 18 2015
.UPDATE... THINGS THIS MORNING ARE EVOLVING GENERALLY AS
ANTICIPATED...ALTHOUGH QUESTION MARKS GOING INTO LATE TODAY STILL
PERSIST IN SOME MEASURE OWING TO THUNDERSTORMS ANCHORED TO THE SE LA
COAST. THESE STORMS WERE PREVIOUSLY SPREADING A LIGHT RAIN SHIELD
INTO MY SOUTHERN ZONES...BUT THE NORTHWARD EXTENT OF THIS PRECIP HAS
SHRUNK IN THE LAST FEW HOURS. ALSO...VIGOROUS STORMS JUST SOUTH OF
THE COAST HAVE BEEN GRADUALLY LOSING COVERAGE SINCE DAYBREAK AND
THEY SHOULD EBB QUICKLY INTO MIDDAY AS UPPER JET PULLING BACK TO THE
WEST REMOVES MUCH OF THE UPPER LEVEL SUPPORT. HOWEVER...IF SAID
EVOLUTION DOES NOT COME TO PASS WITH HASTE THEN MOISTURE TRANSPORT
BLOCKING AND CLOUD COVER INTO SOME OF MY SOUTHERN ZONES WILL HINDER
POTENTIAL FOR VIGOROUS INLAND THUNDERSTORM FORMATION AS WE GO INTO
THIS AFTERNOON.
BUT ASSUMING THE LATTER CAVEAT IS NOT AN ISSUE...LATEST HRRR AND
DOWNSCALED NAM RUNS POINT TO WORRISOME STORMS MOVING INTO MY
SOUTHERN ZONES (ESPECIALLY SOUTH CENTRAL AND SE MS) ZONES FROM MID
AFTERNOON THROUGH MID EVENING. ATMOSPHERIC LAPSE RATES WILL MAINLY
BE AT OR LESS THAN 6 C/KM IN THE H700-H500 LAYER BUT MLCAPE PEAKING
OVER 1000 J/KG SHOULD BE SUFFICIENT GIVEN EXPECTED LOW LEVEL AND
DEEP LAYER SHEAR TO PRODUCE ORGANIZED STORMS. ONCE AGAIN...A FEW
TORNADOES CANNOT BE RULED OUT.
THERE IS NOT ENOUGH EVIDENCE YET TO GO CHANGING THE PREVIOUS
FORECAST AND SEVERE WEATHER EXPECTATIONS MUCH. HOWEVER...WE WILL BE
WATCHING TRENDS CLOSELY OVER THE NEXT FEW HOURS AND WILL SEE IF VERY
RECENT HRRR HINTS THAT SEVERE RISK WILL BE STRONGLY FOCUSING
SOUTHEAST OF THE NATCHEZ TRACE APPEAR SOLID. IF THAT IS THE CASE WE
WILL UPDATE ACCORDINGLY...BUT EVEN IF WE DO FOCUS THE SEVERE RISK
EVEN MORE CONSIDERABLY IN SOUTHERN ZONES THE RISK OF LOCALIZED
FLOODING PROBLEMS STILL LOOKS TO EXTEND ACROSS A MUCH LARGER PORTION
OF THE FORECAST AREA. /BB/
&&
.AVIATION...IFR CATEGORY STRATUS PREVAILS ACROSS THE TAF SITES THIS
MORNING WITH SHOWERS MOVING ACROSS HBG. EXPECT THESE CONDITIONS TO
PERSIST UNTIL LATE MORNING/EARLY AFTERNOON BEFORE FINALLY MIXING
OUT. SHRA WILL MOSTLY CONFINED TO LOCATIONS SOUTH OF THE HEZ-HBG
CORRIDOR THIS MORNING AS A CONVECTIVE COMPLEX SLIDES EASTWARD ALONG
THE COAST...BUT A NEW ROUND OF SHRA/TSRA IS EXPECTED BY MID/LATE
AFTERNOON LASTING INTO THE EVENING WITH AN APPROACHING DISTURBANCE.
THERE MAY BE A WINDOW OF OPPORTUNITY FOR BETTER FLYING CONDITIONS
DURING THE EARLY AFTERNOON...FOLLOWED BY POOR FLYING CONDITIONS
PERSISTING FROM MID/LATE AFTERNOON THROUGH THE EVENING.
/EC/15/
&&
.PREV DISCUSSION... /ISSUED 454 AM CDT SAT APR 18 2015/
SHORT TERM...TODAY THROUGH TONIGHT...AN ACTIVE WEATHER WEEKEND IS
IN STORE AS TWO ROUNDS OF SEVERE WEATHER ARE EXPECTED TO IMPACT THE
ARKLAMISS. THE FIRST ROUND WILL BE INITIATED BY INCREASINGLY
FAVORABLE CYCLONIC AND SHEARED FLOW DEVELOPING OVER THE LOWER MS
VALLEY REGION LATER THIS AFTERNOON AND EVENING. THE CONVECTIVE SYSTEM
CURRENTLY MOVING EAST ALONG THE THE LA COAST WILL DELAY TIMING OF THE
MORE SIGNIFICANT THUNDERSTORM ACTIVITY UNTIL MID/LATE AFTERNOON...BUT
VERY MOIST AND UNSTABLE AIR WITH PRECIPITABLE WATER VALUES > 1.75
INCHES AND ML CAPE NEAR 1000 J/KG SHOULD BE AVAILABLE FOR VIGOROUS
CONVECTIVE DEVELOPMENT AT THAT TIME. WITH DEEP LAYER AND LOW LEVEL
SHEAR ON THE INCREASE...STILL EXPECT ORGANIZED STORMS TO DEVELOP WITH
THE MOST FAVORABLE SET-UP FOR SEVERE WEATHER AND HEAVY RAINFALL
ALONG/SOUTH OF THE I-20 CORRIDOR...BUT WILL SAY THAT CONFIDENCE IS A
LITTLE SHAKIER NOW ON THIS SCENARIO BASED ON RECENT HIGH RES GUIDANCE
TRENDS. IF THE NEXT ROUND OF CONVECTIVE DOES NOT MATERIALIZE AS
ANTICIPATED DUE TO THE MORNING CONVECTION...OR IF IT DEVELOPS FARTHER
EAST...THEN IT IS POSSIBLE THAT MORE ROBUST CONVECTION WOULD IMPACT
NORTHERN PORTIONS OF THE ARKLAMISS AND THIS COULD ALLOW THE SEVERE
WEATHER/HEAVY RAINFALL THREAT TO SHIFT FARTHER NORTH AS WELL. STAY
TUNED FOR UPDATES TO THIS FORECAST LATER THIS MORNING AS CONVECTIVE
EVOLUTION HOPEFULLY BECOMES A LITTLE MORE CLEAR. /EC/
SUNDAY THROUGH SUNDAY NIGHT...MODELS FOR SUNDAY CONTINUE TO SUPPORT
THE RISK FOR SEVERE STORMS ALONG WITH SOME POTENTIAL FOR A HIGHER END
EVENT. WHAT IS STARTING TO BECOME MORE CLEAR IS MUCH OF THE DAY LOOKS
TO BE IN A LULL FROM CONVECTION AFTER MORNING ACTIVITY DEPARTS TO THE
EAST AND THE ROUND OF STORMS WILL BE MORE FOCUSED LATER BETWEEN A 5PM
TO 3AM WINDOW. IN THE WAKE OF THE SAT SYSTEM...MUCH STEEPER LAPSE
RATES WILL SPREAD OVER THE AREA (7.0 TO 7.5 C/KM)(29-31C VERTICAL
TOTALS). ALOFT MUCH COLDER TEMPS WILL MOVE IN WITH H5 READINGS OF -15
TO - 16C. THIS WILL ALL SUPPORT SBCAPE OF 2000-3000 J/KG AS SFC
HEATING REACHES AROUND 80 DEGREES. THIS WILL ALL SUPPORT VIGOROUS
STORMS WITH ROBUST UPDRAFTS. CONCURRENT WITH THIS WILL BE AN OVERALL
DRIER ATMOSPHERE COLUMN AS WELL WITH PWS AROUND 1.2 INCHES. THIS WILL
LEND TO KEEPING STORMS MORE DISCRETE ALONG WITH AN EASTWARD DEEP
LAYER (0-6KM) SHEAR VECTOR OF 40-50KTS. EXPECTATIONS ARE FOR NOT MANY
(ISO/SCT) SUPERCELLS THAT WILL PACK QUITE THE PUNCH. LARGE HAIL >
GOLF BALL SIZE APPEARS VERY POSSIBLE ALONG WITH DAMAGING WINDS WHICH
ALSO COULD BE HIGHER END. DUE TO THIS POSSIBILITY OF SEEING
SIGNIFICANT TYPE WEATHER (>2 IN HAIL)...WILL UP OUR OUTLOOK TO SIG
OVER A DECENT PORTION OF THE NW. ELSEWHERE THE OUTLOOK WILL REMAIN
SIMILAR AS STORMS MAY LOSE SOME POTENCY AS THEY PUSH FURTHER EAST AND
GET LATER INTO THE OVERNIGHT. /CME/
LONG TERM...MONDAY THROUGH SATURDAY....MONDAY MORNING THE LARGE
CLOSED LOW IS EXPECTED TO BE CENTERED OVER THE UPPER MISSISSIPPI
VALLEY WITH ASSOCIATED LARGE AMPLITUDE UPPER LEVEL TROUGHING OVER
THE EASTERN TWO THIRDS OF THE CONUS. MODELS AGREE THAT THE
ASSOCIATED SURFACE LOW WILL BE OVER THE WESTERN GREAT LAKES REGION
MONDAY MORNING BUT THERE ARE TIMING DIFFERENCES WITH THE TRAILING
COLD FRONT THAT IS EXPECTED TO BE OVER SOUTHEAST MISSISSIPPI.
CONSENSUS PLACES THIS COLD FRONT AND THE BULK OF THE PRECIPITATION
JUST SOUTHEAST OF OUR CWA AT DAYBREAK BUT WL MAINTAIN LOW CHANCES OF
LIGHT RAIN IN OUR NORTHEAST THROUGH MID MORNING AS A WEAK SHORTWAVE
PASSES OVER OVERHEAD. DRY WEATHER IS EXPECTED AREAWIDE BY NOON.
SLIGHTLY COOLER AND MUCH DRIER AIR WILL FILTER INTO OUR CWA MONDAY
KNOCKING DEW POINTS INTO THE 40S DURING THE AFTERNOON. DRY WEATHER
IS EXPECTED TO LAST OVER OUR CWA THROUGH TUESDAY AS A SURFACE HIGH
MOVES EAST ACROSS OUR AREA. THIS SURFACE HIGH WILL SHIFT EAST
WEDNESDAY AND THE RESULTING RETURN FLOW WILL INCREASE MOISTURE TO
SUPPORT RAIN CHANCES AGAIN FROM THE WEST BY WEDNESDAY AFTERNOON.
WARMER THAN NORMAL TEMPERATURES AND GREATER RAIN CHANCES ARE
EXPECTED FOR THE END OF THE WEEK BUT THERE ARE SIGNIFICANT
DIFFERENCES IN THE MODELS WITH SOME MAIN FEATURES. THE NORTHERN
CLOSED LOW WILL MOVE SLOWLY EAST ACROSS THE GREAT LAKES REGION
TUESDAY AND WEDNESDAY AND BE OVER THE NEW ENGLAND STATES BY FRIDAY.
THIS LOW WILL TRY TO HELP SUPPORT ANOTHER COLD FRONT DROPPING INTO
OUR CWA THURSDAY INTO FRIDAY BUT INDUCED SHORTWAVE RIDGING
DOWNSTREAM OF A SECOND CLOSED LOW MOVING OVER THE DESERT SOUTHWEST
THURSDAY LOOKS TO IMPEDE THE COLD FRONT INTO OUR AREA. SHORTWAVES
ROUNDING THE BASE OF THE SOUTHERN CLOSED LOW LOOK TO COMBINE WITH
INCREASING MOISTURE AND DAYTIME HEATING FOR A ROUND OF CONVECTION
THURSDAY AND FRIDAY. BOTH GFS AND ECMWF OPEN THE CLOSED LOW AND
BRING THE REMAINING SHORTWAVE TROUGH ACROSS OUR REGION SATURDAY BUT
DIFFER ON THE SURFACE FEATURES WITH THE GFS DEPICTING A MUCH DEEPER
LOW AND STRONGER COLD FRONT ACROSS OUR AREA. FOR NOW...GREATEST POPS
THROUGH THE LONG TERM WILL BE CARRIED FRIDAY AND FRIDAY NIGHT. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 75 64 81 61 / 83 66 31 39
MERIDIAN 76 65 82 64 / 73 78 37 34
VICKSBURG 73 64 81 59 / 87 53 34 46
HATTIESBURG 77 66 84 65 / 87 75 33 28
NATCHEZ 75 64 82 60 / 91 44 28 42
GREENVILLE 73 63 81 57 / 65 72 49 57
GREENWOOD 74 63 79 59 / 61 78 44 56
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
BB/15/EC/22
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
645 AM CDT Sat Apr 18 2015
.DISCUSSION...
Issued at 411 AM CDT SAT APR 18 2015
Overview: Closed and cut-off upper low now over central CO will be
the primary weather driver for the weekend. Feature will open up by
Sunday and move east in response to a shortwave trough digging
southeast through the Northern Rockies. Expect to see a several
rounds of active convection Saturday and Sunday.
Today - Sunday:
While eyes have been fixated on the closed upper low now over CO/NM
the real weather makers will be periodic vorticity lobes and
associated layered frontogenesis that rotate northeast out from
under the upper low. Little going on over the CWA early this morning
as we`re lacking any discernible feature to initiate any convection.
But we are finally seeing the long awaited next round of convection.
Regional radars have recently lit up from OK northward through
central KS albeit further west than we`ve been expecting. Favor
following the HRRR reflectivity trends, which have slowed down the
arrival of the KS/OK convection and latest NAM mass fields/h7
vorticity prog. Thus have pared back PoPs significantly for first
part of morning and slowed the eastward expansion of precipitation.
Even still this is a forecast which will need adjusting throughout
the day as the convection tied to the upper low has had repeated
false starts as well as expanding too fast to the east.
Thickening cloud cover and rain-cooled air will affect temperatures
over the western half of the CWA more so than the eastern half where
precipitation will move in later in the day. Precipitable water
values around two standard deviations above normal suggest potential
for 1"+ rains through tonight. Weak shear and MUCAPEs under 1000J/kg
favor convection remaining below severe limits.
Should see a lull in the rain later tonight and first part of Sunday
before the next wave of convection moves in. The upper low will have
opened up by then and will accelerate eastward. Anticipate convection
increasing as it moves east through the CWA in response to improving
upper level dynamics and low-level convergence associated with a
cold front. However, once again the 0-6km shear of 20-25kts and
modest MUCAPEs favor convection being sub-severe.
Monday - Tuesday:
A fairly deep upper trough stretching from MN through the Mid MS
Valley will influence our weather with widespread subsidence on the
backside of the trough. Abundant solar insolation will help offset
cold air advection but still result in below average temperatures.
Wednesday - Friday:
As the upper trough shifts east through the Great Lakes an upper
ridge will build eastward through the Rockies and into the
Central/Southern Plains. Medium range models are in agreement that a
cold front will surge through the region on Wednesday. However, they
disagree on whether or not convection will be generated. Moisture
fields look minimal and believe any shower activity will be widely
scattered.
As we get into Thursday and Friday the ECMWF and GFS both lift a
shortwave out of the southwestern U.S. but the GFS appears
unrealistic in deepening a surface over the Central High Plains and
spreading warm advection convection too far downstream. Will use a
blended forecast but overall confidence low for Thursday`s PoPs but
timing looks better for the PoPs on Friday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 641 AM CDT SAT APR 18 2015
A large area of showers and thunderstorms will evolve and lift north
through eastern KS and western MO during the morning and afternoon
hours. Generally VFR conditions with occasional MVFR cig/vsby
restrictions with the stronger storms. Should see the rain
temporarily end from west to east during the evening hours.
Another band of showers and isolated storms may reach eastern KS and
west central MO by the pre-dawn hours of Sunday morning with
generally VFR conditions.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
DISCUSSION...MJ
AVIATION...MJ
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
625 AM CDT SAT APR 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT SAT APR 18 2015
SPC SUGGESTED SIGNIFICANT SEVERE WEATHER POTENTIAL THIS AFTERNOON
AND EARLY THIS EVENING ACROSS PARTS OF SOUTHWEST AND NCNTL NEB. A
PORTION OF THE LOW PRESSURE ACROSS SWRN KS THIS MORNING IS
EXPECTED TO LIFT NORTHEAST THROUGH SCNTL AND ERN NEB THIS
AFTERNOON SETTING UP A UNSTABLE WARM SECTOR FROM ROUGHLY IMPERIAL
TO ONEILL.
ALTHOUGH THE RAP IS FAIRLY QUIET THE NAM AND HRRR SBN MODELS
SUGGEST REASONABLE POTENTIAL FOR CONVECTIVE DEVELOPMENT THIS AFTN
IF SKIES PARTIALLY CLEAR ALLOWING FOR TEMPERATURES TO RISE INTO
THE MID AND UPPER 60S. SATELLITE SHOWS CLEARING THIS MORNING
ACROSS CNTL HIGH PLAINS OF KS/COLO AND IT IS BELIEVED THIS
CLEARING WILL MOVE INTO SCNTL NEB THIS AFTN.
THE STORM ACTIVITY COULD BEGIN AS EARLY AS 18Z IN THE SOUTHWEST
WITH THE NAM SOLN OR AS LATE AS 21Z-00Z IN THE HRRR MODEL.
SATELLITE TIMING TOOLS INDICATE THE CLEARING ACROSS KS COULD
REACH SOUTHWEST NEB BY 13-15Z THIS MORNING WHICH WOULD PROVIDE A
GOOD START FOR MODEST HEATING GIVEN THAT THIS CLEARING AREA WOULD
TEND TO FILL IN WITH DEVELOPING CUMULUS.
ONE WEAKNESS ARE THE WIND FIELDS 500MB AND BELOW WHICH ARE LIGHT
PRODUCING BULK SHEAR VALUES OF 30KT OR LESS WHICH MIGHT SUPPORT
MORE OF HEAVY RAIN THREAT. STILL TEMPERATURES ALOFT WILL BE VERY
COLD AS THE H500MB LOW ACROSS COLO MOVES EAST TO NEAR
LIMON/SPRINGFIELD. WINDS AT 300MB ARE STRONG NEAR 65KT
POTENTIALLY ENHANCING UPDRAFTS AND PROVIDING VENTILATION.
FREEZING LEVELS ARE NEAR 5KFT SUPPORTING A LOW TOP STORM
ENVIRONMENT AND GOOD POTENTIAL FOR HAIL. THE NAM IS PRODUCING
AROUND 2000 J/KG OF CAPE AT NORTH PLATTE AND BROKEN BOW WHILE THE
RAP AND OTHER MODELS SHOW HALF OR LESS THAT VALUE.
NORTHWEST WINDS WILL SWEEP IN FROM THE WEST IN THE WAKE OF THE
DISTURBANCE TONIGHT. THIS SHOULD PRODUCE DRYING AND DECREASING
RAIN CHANCES FROM MIDNIGHT ONWARD.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 328 AM CDT SAT APR 18 2015
SUNDAY WILL SEE THE STRONG LOW PRESSURE WEAKENING AS IT PUSHES
EAST WHILE A TROUGH DIGS ACROSS THE CANADIAN PLAINS. SOME
LINGERING SUNDAY MORNING SHOWERS ARE POSSIBLE IN THE EASTERN
ZONES...HOWEVER THE BIGGER EVENTS OF THE DAY WILL BE THE CAA AND
INCREASING NW WINDS. AS THE LOW PUSHES ACROSS KS...DRY AIR WILL
QUICKLY FILL IN BEHIND...RESULTING IN DECREASING CLOUDS FROM WEST
TO EAST IN THE MORNING. BY AFTERNOON SHOULD SEE MOSTLY SUNNY
SKIES FOR ALL. THE SUN WILL COMBINE WITH THE STRONG NW WINDS
/GUSTING TO 30 TO 40 MPH/ TO PROMOTE GOOD MIXING OF THE BL AND
OFFSET THE CAA AND TEMPS PUSH INTO THE 50S.
EARLY IN THE WEEK THE TROUGH DIGS TOWARDS THE GREAT LAKES REGION
AND ABSORBS THE SOUTHERN LOW. ELONGATED SFC HIGH PRESSURE BUILDS
ACROSS THE HIGH PLAINS. THE ACTIVE WEATHER IS WELL TO THE NE
ALTHOUGH A FEW UPPER LEVEL DISTURBANCES WILL RIDE ALONG THE NW
FLOW OVERHEAD AND BRING SOME PASSING CLOUDS AT TIMES. LIMITED
MOISTURE IN THE LOWER LEVELS AND MODELS/FORECAST ARE DRY. TEMPS
TO START THE WEEK WILL BE CHILLY IN THE MORNING WITH MOST AREAS
NEAR OR BELOW THE FREEZING MARK. STILL A COUPLE OF WEEKS FROM
TYPICAL LAST FREEZE FOR MOST OF THE AREA...SO NO HEADLINES NEEDED
YET. HIGHS REBOUND NICELY WITH A WARMING TREND WITH 60S MAYBE 70
FOR WED AND THURS.
EYES THEN FOCUS ON A TROUGH AS IT DIGS ACROSS THE SOUTHWEST.
MODELS IN GOOD AGREEMENT DEVELOPING A CLOSED 500 MB LOW NEAR SRN
CAL BY THURS. THE LOW THEN LIFTS TOWARDS THE 4 CORNERS WHILE
BECOMING AN OPEN WAVE. THE WAVE WILL THEN PUSH ACROSS THE PLAINS
TO END THE WEEK. THIS WILL BRING A RETURN OF THE ACTIVE
WEATHER...AND WILL HAVE POPS TOWARDS THE END OF THE EXTENDED
PERIOD. STILL HAVE SOME LOCATION AND TIMING ISSUES TO IRON OUT
WHICH IS TYPICAL THIS FAR OUT SO POPS KEPT BELOW 50 PERCENT FOR
NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 625 AM CDT SAT APR 18 2015
MIXED FLIGHT CONDITIONS CONTINUE TODAY. VFR IS EXPECTED THIS
MORNING ACROSS SWRN/SCNTL NEB AS A CLEAR SLOT MOVES IN FROM THE
SOUTH. THIS AREA OF CLEARING WILL WARM UP AND DESTABLIZE THIS
AFTN WITH SCATTERED SHRA/TSTM COVERAGE DEVELOPING 18Z-21Z AND
CONTINUING THROUGH ABOUT 03Z THIS EVENING. STORMS WHICH DEVELOP
WILL LIKELY LIFT NORTH TOWARD KVTN THIS EVENING AROUND 03Z-06Z.
A COLD FRONT WILL SWEEP INTO THE FCST AREA FROM THE NORTHWEST TONIGHT
BETWEEN 03Z-09Z PRODUCING MVFR CIGS AND SCATTERED SHOWERS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
646 AM EDT SAT APR 18 2015
.SYNOPSIS...
WEAKENING LOW PRESSURE OFFSHORE AND AN APPROACHING DISTURBANCE
ALOFT FROM THE WEST WILL MAINTAIN SCATTERED SHOWERS TODAY. A WARM
FRONT WILL LIFT NORTH ACROSS THE AREA SUNDAY AND SUNDAY NIGHT
BRINGING WIDESPREAD SHOWERS AND THUNDERSTORMS. THIS WILL BE
FOLLOWED BY A COLD FRONT MONDAY NIGHT...WITH DRY AND SEASONABLE
HIGH PRESSURE TO FOLLOW THROUGH THE MIDDLE OF THE UPCOMING WEEK.
THIS HIGH PRESSURE WILL MOVE OFFSHORE THURSDAY BRINGING A RETURN
TO ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM SATURDAY...THE ONLY TWEAKS TO THE FORECAST THIS
MORNING ARE TO INCREASE POPS TO 80-100 PERCENT ALONG AND EAST OF
I-95 FOR THE LARGE AREA OF RAIN AND EMBEDDED CONVECTIVE SHOWERS
MOVING EAST TOWARD THE COAST. LATEST HRRR AND HRRRX MODELS SHOW
THIS ACTIVITY MOVING OFF THE COAST BY 15Z-16Z (11 AM TO NOON) WITH
SCATTERED SHOWERS REDEVELOPING FARTHER INLAND FOR THE AFTERNOON.
DISCUSSION FROM 300 AM FOLLOWS...
A VERY NEBULOUS SURFACE PRESSURE PATTERN EXISTS ACROSS THE
CAROLINAS. WEAK LOW PRESSURE DEVELOPED A COUPLE DAYS AGO ALONG AN
OLD STALLED FRONT NEAR SAVANNAH. THIS LOW IS NOW DISSIPATING WELL
EAST OF THE SOUTH CAROLINA COAST DUE TO LACK OF BAROCLINICITY.
THIS WILL LEAVE VIRTUALLY NO SURFACE FEATURES OF NOTE
TODAY...LEAVING WINDS AT THE MERCY OF LOCAL EFFECTS LIKE THE
AFTERNOON SEABREEZE CIRCULATION PLUS ANY SHOWER OUTFLOW
BOUNDARIES.
AN UPPER LEVEL DISTURBANCE IS MOVING EASTWARD ACROSS THE CAROLINAS
THIS MORNING. THIS FEATURE SHOULD BRING GOOD CHANCES OF SHOWERS...
ESPECIALLY TO COASTAL SOUTH CAROLINA...WITH PRECIPITATION COVERAGE
EXPECTED TO DECREASE MARKEDLY IN THE FIRST FEW HOURS AFTER DAYBREAK.
STRONG APRIL SUNSHINE WILL CUT THROUGH THE REMAINING CLOUD COVER AND
HIGHS SHOULD STILL APPROACH 80 INLAND...WITH MID 70S NEAR THE COAST.
ALTHOUGH PRECIPITATION CHANCES MAY NOT INCREASE APPRECIABLY DURING
THE AFTERNOON AT THE COAST...TEMPS NEAR 80 SHOULD TRIGGER SCATTERED
SHOWERS INLAND WITH COVERAGE PROBABLY AROUND 30 PERCENT.
ANOTHER UPPER DISTURBANCE WILL APPROACH THE EASTERN CAROLINAS VERY
LATE TONIGHT FROM THE SOUTHWEST. HIGH PRESSURE OVER SE CANADA WILL
BEGIN TO BUILD DOWN THE EASTERN SEABOARD LATE TONIGHT AS WELL...WITH
A BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTHEAST AROUND
SUNRISE SUNDAY. LOWS SHOULD FALL INTO THE LOWER TO MIDDLE 60S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...STILL SHAPING UP TO BE A VERY WET PERIOD FOR
THE SHORT TERM AHEAD OF A COLD FRONT WHICH WILL CROSS THE AREA
MONDAY NIGHT.
SUNDAY WILL BEGIN DRY ACROSS MOST OF THE AREA...BUT THIS WILL
QUICKLY CHANGE AS A LOW PRESSURE SYSTEM BENEATH A POTENT SHORTWAVE
DEVELOPS AND MOVES OUT OF THE GULF STATES AND INTO THE OHIO VLY. A
WARM FRONT AHEAD OF THIS FEATURE WILL MOVE OVERHEAD THE
CAROLINAS...WITH A SECONDARY AREA OF LOW PRESSURE POSSIBLY
DEVELOPING OVERHEAD LATE SUNDAY NIGHT. DEEP SW FLOW WILL INTENSIFY
LATE SUNDAY...WITH 850MB V-WIND COMPONENT REACHING +3 SD`S LATE
SUNDAY NIGHT...SUPPORTING AN ENVIRONMENT OF POTENTIALLY RECORD-FOR-
THE-DAY PRECIPITABLE WATER AS COMPARED AGAINST THE SPC SOUNDING
CLIMATOLOGY. ALTHOUGH A NICE SUBTROPICAL JET WILL ARC ACROSS THE
MEXICO/US BORDER SUNDAY NIGHT...THIS WILL NOT AID IN ANY LIFT SO
UPPER SUPPORT LOOKS TO BE PRETTY WEAK INVOF THIS SYSTEM.
HOWEVER...SURFACE CONVERGENCE NEAR THE LOW PRESSURE COMBINED WITH
STRONG LOW-LEVEL MOISTURE TRANSPORT...WARM CLOUD DEPTH OF 11-12
KFT...AND ONLY WEAK INSTABILITY WHICH PROVIDES LONG PARCEL RESIDENCE
TIMES WITHIN THE SATURATED COLUMN...SUGGEST PERIODS OF HEAVY
RAINFALL WILL OCCUR...ESPECIALLY SUNDAY NIGHT. INSTABILITY LOOKS
PRETTY LIMITED SO THUNDER WILL BE ONLY ISOLATED...BUT HEAVY SHOWERS
PRODUCING WIDESPREAD 1" OF QPF OR MORE LOOKS VERY LIKELY INTO MONDAY
MORNING.
MUCH DRIER AIR WILL FILTER INTO THE REGION MONDAY...BUT CONTINUED
DEEP SW FLOW AND THE APPROACH OF A COLD FRONT WILL STILL CREATE THE
POTENTIAL FOR SCATTERED SHOWERS. BEST CHANCE WILL BE LATE MONDAY
INTO MONDAY NIGHT IMMEDIATELY AHEAD OF AND ALONG THE
BOUNDARY...WHICH IS PROGGED TO MOVE OFFSHORE BY THE END OF THE
PERIOD.
TEMPS THROUGH THE PERIOD WILL BE NORMAL-TO-ABOVE FOR MID-APRIL.
MONDAY WILL BE THE WARMER DAY WITH FEWER CLOUDS ALLOWING FOR MORE
INSOLATION TO WARM THE SURFACE. 850MB TEMPS BOTH DAYS WILL BE 12-
14C...BUT CLOUDS AND RAIN WILL KEEP HIGHS IN THE MID 70S
SUNDAY...WARMING INTO THE LOW 80S AWAY FROM THE COAST MONDAY. LOWS
SUNDAY NIGHT WILL STRUGGLE TO DROP ONLY INTO THE UPR 60S...LOW 60S
BEHIND THE FRONT MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...COLD FRONT WILL BE OFFSHORE TUESDAY
MORNING...AND A PRIMARILY QUIET WEEK LOOKS TO BE ON TAP FOR THE
EXTENDED. HIGH PRESSURE WILL MOVE ACROSS THE SOUTHERN TIER OF STATES
TUE-THU BEFORE PUSHING OFFSHORE LATE IN THE WEEK. THIS OCCURS IN
RESPONSE TO FORCED-ZONAL FLOW SOUTH OF A LARGE CLOSED LOW WHICH WILL
SIT AND SPIN ACROSS SE CANADA THROUGH MUCH OF THE WEEK. THE
CAROLINAS WILL BE ON THE PERIPHERY OF THIS FEATURE...SO WHILE COOLER
TEMPS WILL OCCUR TUE/WED...SEASONABLE VALUES ARE ANTICIPATED. LATE
IN THE PERIOD AS THE HIGH PUSHES OFFSHORE...MOIST RETURN FLOW WILL
DEVELOP AND SHOWER ACTIVITY WILL BECOME POSSIBLE ONCE AGAIN
THURSDAY...AND ESPECIALLY FRIDAY. FRIDAY WILL FEATURE THE BEST
CHANCES FOR PRECIP BOTH DUE TO INCREASED COLUMN MOISTURE...BUT ALSO
THANKS TO A COLD FRONT WHICH WILL APPROACH FROM THE NW...DRIVEN BY A
PIECE OF VORT ENERGY ROTATING AROUND THE AFOREMENTIONED LARGE UPPER
LOW. TEMPS THU/FRI WILL RETURN TO ABOVE NORMAL HOWEVER.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...A RATHER LARGE BATCH OF PRECIP IS CURRENTLY PASSING
THROUGH THE CWA FROM WEST TO EAST...ASSOCIATED WITH A SHORT WAVE.
LOOK FOR INTERMITTENT MVFR WITH POSSIBLE BRIEF IFR PERIODS IN THE
HEAVIER PRECIP. THE SHORTWAVE AND ASSOCIATED PRECIP WILL EXIT THE
REGION BY LATE MORNING...HOWEVER IT IS LIKELY THAT MVFR CEILINGS
WILL REMAIN FOR SOME TIME AFTER THAT. HIGH PRESSURE CENTERED TO OUR
NORTH WILL GIVE US LIGHT NORTHEAST FLOW TODAY. THROUGH THE EVENING
HOURS MAINLY A MID CLOUD CEILING WILL PREVAIL.
EXTENDED OUTLOOK...SHOWERS ACCOMPANIED WITH ISOLATED THUNDER TO
AFFECT THE FORECAST AREA LATE SUNDAY THROUGH MONDAY
MORNING...RESULTING IN OCCASIONAL MVFR AND IFR CONDITIONS. SCATTERED
PCPN ASSOCIATED WITH A CFP MONDAY NIGHT FOLLOWED BY MAINLY VFR
CONDITIONS TUE THROUGH WED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM SATURDAY...ADJUSTED FORECAST WIND DIRECTIONS 20-30
DEGREES COUNTERCLOCKWISE FOR THE NEXT 3-4 HOURS BASED ON CURRENT
OBSERVATIONS...OTHERWISE NO SIGNIFICANT CHANGES HAVE BEEN MADE TO
THE FORECAST. DISCUSSION FROM 300 AM FOLLOWS...
A VERY DISORGANIZED SURFACE WEATHER PATTERN EXISTS ACROSS THE
AREA. WEAK LOW PRESSURE THAT DEVELOPED A COUPLE DAYS AGO ALONG AN
OLD STATIONARY FRONT IS DISSIPATING OFF THE SOUTH CAROLINA COAST.
MORE IMPORTANT TO OUR WEATHER WILL BE THE PASSAGE OF AN UPPER
LEVEL DISTURBANCE THIS MORNING WHICH PROMISES TO BRING GOOD
CHANCES FOR SHOWERS. BEHIND THIS DISTURBANCE LOOK FOR PARTIAL
CLEARING AND A REDUCTION IN RAIN COVERAGE FOR THE AFTERNOON. BY
LATE TONIGHT THE APPROACH OF ANOTHER DISTURBANCE FROM THE
SOUTHWEST COULD BRING INCREASING SHOWER CHANCES IN AROUND
DAYBREAK.
VARIABLE WINDS TODAY SHOULD REMAIN 10 KNOTS OR LESS. SEAS AS HIGH AS
4 FEET IN THE 10-20 MILE OFFSHORE WATERS NEAR CAPE FEAR WILL SUBSIDE
THIS AFTERNOON...WITH 2-3 FEET SEAS EXPECTED FOR ALL AREAS. VERY
LATE TONIGHT HIGH PRESSURE OVER SE CANADA WILL PUSH A BACKDOOR FRONT
TOWARD THE AREA...WITH INCREASING NE WINDS EXPECTED AROUND DAYBREAK
SUNDAY.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...STRENGTHENING SOUTHERLY FLOW AHEAD OF A COLD
FRONT WILL PRODUCE GUSTY WINDS AND A POSSIBLE SHORT SCA SUNDAY NIGHT
INTO MONDAY. BEFORE THIS TIME...WINDS WILL VEER FROM E TO S THROUGH
SUNDAY AS HIGH PRESSURE MOVES OFF TO THE NE AND A WARM FRONT LIFTS
ACROSS THE WATERS. AS THE WINDS VEER THEY WILL INCREASE AS
WELL...BECOMING 15-20 KTS SUNDAY NIGHT INTO MONDAY...AND THESE WINDS
WILL PUSH SEAS UP TO 3-6 FT...HIGHEST ACROSS THE NC WATERS. A SHORT
DURATION SCA STILL LOOKS LIKELY AND IS HIGHLIGHTED IN THE HWO. WINDS
WILL SLOWLY VEER THROUGH MONDAY TO THE SW AT SIMILAR SPEEDS...BEFORE
THE COLD FRONT CROSSES THE WATERS AT THE END OF THE PERIOD WITH A
WIND SHIFT TO THE NW. SEAS MONDAY WILL BE 3-5 FT AHEAD OF THE COLD
FRONT...BEFORE FALLING AS THE WINDS TURN OFFSHORE LATE.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...HIGH PRESSURE MOVING ACROSS THE SOUTHERN
TIER OF THE NATION WILL DRIFT ACROSS THE WATERS DURING WEDNESDAY.
AHEAD OF THIS...LIGHT NW WINDS WILL OCCUR OVER THE WATERS...BECOMING
VARIABLE WEDNESDAY AS THE GRADIENT WEAKENS...AND EVENTUALLY TURNING
TO THE SW LATE...BUT STILL AT SPEEDS GENERALLY 10 KTS OR LESS. A
VERY BRIEF PERIOD OF 3-5 FT SEAS ARE POSSIBLE EARLY
TUESDAY...LEFTOVERS FROM THE MORE STRONGLY FORCED SEAS ON
MONDAY...BEFORE FALLING TO 2-3 FT AND PERSISTING THROUGH MID-WEEK.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
921 AM CDT SAT APR 18 2015
.UPDATE...
ISSUED AT 920 AM CDT SAT APR 18 2015
WILL CONTINUE TO FAVOR THE TRENDS OF THE 10-13 UTC HRRR ITERATIONS
WHICH KEEP THE BAND OF PRECIPITATION ACROSS SOUTHERN SOUTH DAKOTA
AND EASTERN NEBRASKA IN ASSOCIATION WITH THE UPPER LEVEL LOW FOR
THE MOST PART TO THE SOUTH OF NORTH DAKOTA UNTIL 22-24 UTC THIS
EVENING GIVEN DRY EAST-SOUTHEASTERLY LOW LEVEL FLOW PRECEDING
THIS SYSTEM. BETTER CHANCES FOR SHOWER ACTIVITY THIS AFTERNOON ARE
ACROSS THE WEST AS A COLD FRONT ACROSS EASTERN MONTANA THIS
MORNING ENTERS WESTERN NORTH DAKOTA THIS AFTERNOON. DID ADD A
MENTION OF THUNDERSTORMS TO THE WEST ALONG THE FRONT WITH SOME
WEAK INSTABILITY DEPICTED ON THE 06 UTC NAM/GFS BUFR SOUNDINGS.
UPDATE ISSUED AT 626 AM CDT SAT APR 18 2015
A FEW WEAK RADAR ECHOS ARE TRYING TO SNEAK INTO THE SOUTH CENTRAL
PART OF THE STATE...THOUGH THESE APPEAR WEAK AND DOUBTFUL MORE THAN
A FEW SPRINKLES COULD BE HITTING THE GROUND. WITH THAT SAID...LATEST
GUIDANCE IS STILL ON TRACK FOR SHOWERS TO BE ON THE INCREASE LATE
DAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 424 AM CDT SAT APR 18 2015
MARGINAL FIRE WEATHER CONDITIONS AND CHANCES FOR MUCH NEEDED
RAIN WILL HIGHLIGHT THE SHORT TERM.
AS TWO UPPER LEVEL LOWS CONVERGE OVER THE NORTHERN PLAINS THROUGH
SATURDAY...MOISTURE TRANSPORT FROM THE SOUTH AND ATMOSPHERIC
INSTABILITY WILL CREATE WIDESPREAD CHANCES FOR RAIN. SOUTHERN AND
EASTERN AREAS OF THE STATE ARE EXPECTED TO HAVE THE GREATEST CHANCES
FOR SUBSTANTIAL RAIN...CONCLUDED THROUGH GOOD AGREEMENT WITH THE
CURRENT 00Z MODEL SUITE. CHANCES FOR RAIN ARE FORECAST TO INITIATE
THROUGH SATURDAY AFTERNOON AND PERSIST INTO SUNDAY MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 424 AM CDT SAT APR 18 2015
ON SUNDAY...DEEPENING TROUGH CLOSES OFF OVER MANITOBA WHILE LOW OVER
THE SOUTHERN PLAINS WASHES INTO THE NORTHERN SYSTEM. PRECIPITATION
CHANCES WILL CONTINUE PRIMARILY OVER CENTRAL AND NORTHERN NORTH
DAKOTA...THOUGH MOISTURE WRAPPING AROUND THE BACK SIDE OF THE SYSTEM
WILL STILL KEEP LOWER PRECIPITATION CHANCES FURTHER SOUTH AND WEST.
GUSTY WINDS EXPECTED THOUGH THE DAY IN TIGHT PRESSURE GRADIENT WITH
SURFACE LOW PUSHING INTO THE MIDWEST. WINDS WILL REMAIN BREEZY
OVERNIGHT WITH LOW RAIN/SNOW CHANCES LINGERING OVER CENTRAL NORTH
DAKOTA.
UPPER LOW PUSHES ALONG THE MINNESOTA/ONTARIO BORDER ON MONDAY. THIS
WILL KEEP LOW PRECIPITATION CHANCES GOING PRIMARILY OVER THE JAMES
RIVER VALLEY. WITH TIGHT PRESSURE GRADIENT ON THE BACK SIDE OF THIS
SYSTEM...WILL KEEP THE STRONGER WINDS MAINLY OVER CENTRAL NORTH
DAKOTA...DECREASING TOWARDS THE WEST.
THROUGH THE REMAINDER OF THE WORK WEEK...UPPER LOW SLOWLY WORKS OFF
TO THE EAST KEEPING NORTH/NORTHWESTERLY FLOW OVER OUR AREA. WITH THE
EXCEPTION OF A FEW SHOWERS POSSIBLE ON TUESDAY AS A FAST MOVING WAVE
SLIDES THROUGH THE FLOW...DRY WEATHER IS EXPECTED. TEMPERATURES WILL
REMAIN A BIT BELOW AVERAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 918 AM CDT SAT APR 18 2015
A COLD FRONT ACROSS EASTERN MONTANA THIS MORNING WILL ENTER
WESTERN NORTH DAKOTA THIS AFTERNOON AND MERGE WITH A LOW
DEVELOPING ACROSS EASTERN SOUTH DAKOTA TONIGHT. SCATTERED RAIN
SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS WESTERN
NORTH DAKOTA THIS AFTERNOON...WITH MORE WIDESPREAD RAIN SHOWERS
POSSIBLE AT KMOT/KBIS/KJMS THIS EVENING AND TONIGHT. EMBEDDED MVFR
CONDITIONS POSSIBLE IN RAIN.
&&
.FIRE WEATHER...
ISSUED AT 424 AM CDT SAT APR 18 2015
RELATIVE HUMIDITY VALUES ARE PROJECTED TO BE IN THE LOWER TO MID
20S THIS AFTERNOON OVER CENTRAL NORTH DAKOTA. WITH SOUTHERLY WINDS
OF AROUND 10 TO 20 MPH...NEAR CRITICAL FIRE WEATHER CONDITIONS
WILL BE POSSIBLE. OVER WESTERN NORTH DAKOTA...A COLD FRONT WILL
PUSH INTO THE AREA BRINGING A WIND SHIFT TO THE NORTHWEST. BEHIND
THE FRONT...WINDS WILL INCREASE TO AROUND 25 MPH. RELATIVE
HUMIDITY VALUES WILL BE HIGHER OVER THIS REGION...INCREASING
BEHIND THE FRONT...THOUGH THIS STILL MAY BRING A PERIOD OF NEAR
CRITICAL FIRE WEATHER CONDITIONS. WETTING RAINS POSSIBLE
TONIGHT...ESPECIALLY OVER THE EASTERN HALF OF THE STATE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...AC
LONG TERM...JJS
AVIATION...AYD
FIRE WEATHER...AC/JJS
AREA FORECAST DISCUSSION
NWS NORMAN OK
646 AM CDT SAT APR 18 2015
.DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
&&
.AVIATION...
HAVE LOW CONFIDENCE OF VFR TO LIFR CONDITIONS IN WESTERN OKLAHOMA
THROUGH 21Z AS WELL AS LOW CONFIDENCE WITH TSRA TIMING/COVERAGE
AFTER 19Z.
CONDITIONS WILL BOUNCE BETWEEN VFR AND LIFR WITH BR/FG ACROSS
WESTERN OKLAHOMA THROUGH 21Z. THE WORST CONDITIONS MAY BE NEAR
KCSM AND KHBR THROUGH 15Z. IFR CONDITIONS MAY AFFECT KSPS AND KLAW
AS WELL THROUGH 15Z...BUT DID NOT MENTION THINKING THESE LOWER
CONDITIONS WILL STAY WEST OF THESE SITES.
HAVE HIGH CONFIDENCE ALL SITES WILL BE VFR BY 21Z.
ISO-NUM TSRA WILL FORM AND AFFECT MANY TAF SITES AFTER 19Z. USED
VCTS/TEMPOS AT MOST SITES EXCEPT KCSM AND KHBR WHERE CONFIDENCE OF
STORMS IS TOO LOW TO MENTION. BRIEF VARIABLE GUSTY WINDS...
HAIL...AND MVFR OR LOWER CONDITIONS ARE POSSIBLE WITH THE
STRONGEST STORMS. MOST STORMS WILL BE EAST OF ALL TAF SITES BY
04Z.
ADDITIONAL MVFR/IFR CONDITIONS MAY DEVELOP AFTER 06Z BUT DID NOT
MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE.
MBS
&&
.PREV DISCUSSION... /ISSUED 419 AM CDT SAT APR 18 2015/
DISCUSSION...
SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING IS THE
MAIN CONCERN.
RAIN CHANCES THIS MORNING LOOK TO BE MAINLY CONFINED TO LOCATIONS
EAST OF I-35 WHERE MOST LATEST RADAR ECHOES WERE OCCURRING FROM A
WEAK IMPULSE ROTATING AROUND A MID/UPPER LOW IN SOUTHERN
COLORADO. NO SEVERE STORMS ARE EXPECTED WITH THIS ACTIVITY...JUST
SOME LOCALIZED HEAVY RAIN. MOST OF THIS ACTIVITY MAY END BY 8 AM
IF THE LATEST HRRR RUNS ARE CORRECT. MOST LOCATIONS WILL REMAIN
DRY THIS MORNING.
ADDED PATCHY FOG MENTION THROUGH 11 AM THIS MORNING ACROSS PARTS
OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS WHERE SOME PARTIAL
CLEARING...ABUNDANT LOW LEVEL MOISTURE...AND LATEST HRRR RUNS
FAVOR SOME DEVELOPMENT. DOUBT IT WILL GET TOO WIDESPREAD OR DENSE.
THIS AFTERNOON AND EVENING...ISOLATED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL DEVELOP ACROSS THE AREA. CAPPING WILL BE RATHER
WEAK. WITH MORE SUN COMPARED TO YESTERDAY...THINK CONVECTIVE
TEMPERATURES WILL BE REACHED RATHER EASILY IN THE 2 TO 5 PM TIME
FRAME. FIRST DEVELOPMENT MAY BE FOCUSED IN WESTERN OKLAHOMA AND
WESTERN NORTH TEXAS NEAR A DEVELOPING DRYLINE. WENT NEAR GUIDANCE
RAIN CHANCES. EXACTLY WHERE AND WHEN STORMS OCCUR REMAINS TRICKY
TODAY AND TONIGHT.
IN REGARDS TO SEVERE POTENTIAL THIS AFTERNOON AND EVENING...
BELIEVE THERE WILL BE SOME SEVERE STORMS WITH LARGE HAIL AS THE
MAIN CONCERN. THE AIR WILL BE MODERATELY UNSTABLE WITH MLCAPE
1500-2500 J/KG. STRONG 0-6 KM SHEAR 30-50 KT SUPPORTS SUPERCELLS
AND MULTICELLS. STRONG 0-3 KM SHEAR VALUES 25-45 KT AND VERY COLD
MID LEVELS WITH 500 MB TEMPERATURES AROUND -18C COULD SUPPORT VERY
LARGE HAIL IN SOME CELLS AS LONG AS CONVECTION IS NOT TOO
WIDESPREAD. SOME DAMAGING WINDS MAY OCCUR AS WELL IF STORMS CAN
ORGANIZE INTO CLUSTERS AND LINES. TORNADO POTENTIAL APPEARS TO BE
LIMITED DUE TO WEAK LOW LEVEL SHEAR...THOUGH NOTICED THE LATEST
RAP13 INDICATED STRONGER LOW LEVEL WINDS POSSIBLY DEVELOPING IN
SOUTHWESTERN OKLAHOMA IN THE 5 TO 9 PM TIME FRAME WHICH MAY
INCREASE THIS POTENTIAL. WILL CLOSELY MONITOR.
LOCALLY HEAVY RAINFALL MAY AGAIN OCCUR LATE THIS AFTERNOON AND
TONIGHT...THOUGH STORM MOTIONS WILL BE FASTER WHICH MAY LIMIT THE
DURATION OF HEAVY RAINFALL IN ONE GIVEN LOCATION.
MOST STORMS WILL MOVE INTO EASTERN OKLAHOMA AFTER MIDNIGHT
TONIGHT...ALLOWING FOR MOIST AND COOL CONDITIONS. WOULD NOT BE
SURPRISED IF SOME FOG FORMED...BUT DID NOT MENTION DUE TO LOW
CONFIDENCE.
ON SUNDAY...A FEW SHOWERS AND STORMS MAY LINGER MAINLY OVER
NORTHERN OKLAHOMA...THOUGH APPEARS THE SEVERE POTENTIAL WILL SHIFT
IN FAR EASTERN OKLAHOMA AND POINTS EAST. WITH LINGERING WEAK
INSTABILITY AND COLD MID/UPPER LEVELS...A FEW STORMS WITH SMALL
HAIL COULD OCCUR. BREEZY CONDITIONS WILL DEVELOP. THERE IS AN
OUTSIDE CHANCE WINDS COULD APPROACH ADVISORY CRITERIA WITH GUSTS
OVER 40 MPH IN NORTHWEST OKLAHOMA. WENT WITH THE WARMER SIDE OF
GUIDANCE TEMPERATURES THINKING SOME SUN WILL OCCUR...ESPECIALLY
EARLY IN THE DAY.
SUNDAY NIGHT THROUGH FRIDAY...A WET PATTERN MAY CONTINUE WITH
RAIN CHANCES REMAINING IN THE FORECAST MOST DAYS. THERE ARE SOME
MODEL DISCREPANCIES WITH WEATHER FEATURES...THUS FORECAST
CONFIDENCE REMAINS LOW. SOME STRONG TO SEVERE STORMS MAY OCCUR
TUESDAY THROUGH FRIDAY WITH NEARBY MOISTURE AND INSTABILITY.
MBS
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
25/17/17
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1040 AM CDT SAT APR 18 2015
.UPDATE...
ISSUED AT 1030 AM CDT SAT APR 18 2015
WITH DRY AIR IN PLACE...ERODING NORTHERN EXTENT OF SHOWER
ACTIVITY...REDUCED POPS/QPF NORTH OF THE MAIN BAND OF
PRECIPITATION FOR THE AFTERNOON IN LINE WITH LATEST HRRR AND RUC
GUIDANCE. LATEST NAM IS IN LINE WITH CURRENT FORECAST AFTER 00Z.
HRRR COLUMN MAX REF DOES LOOK LIKE A WEAK FEW CONVECTIVE CELLS
FORM OVER THE CWA TODAY SO WILL LEAVE MENTION OF THUNDER IN.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 327 AM CDT SAT APR 18 2015
PRECIPITATION CHANCES OVER THE NEXT 24 HOURS...AND WINDS SUNDAY
AND MONDAY WILL BE THE FORECAST CHALLENGES.
A FAIRLY DRY AIR MASS REMAINS IN PLACE ACROSS MOST OF THE CWA THIS
MORNING WITH DEW POINTS MAINLY IN THE UPPER 20S. HIGHER DEW
POINTS ARE ADVECTING NORTHWESTWARD INTO WESTERN SOUTH DAKOTA WHERE
VALUES IN THE 40S. THESE HIGHER DEW POINTS...ALONG WITH SOME
SHOWERS AND THUNDERSTORMS WILL SLOWLY TRACK NORTHWARD THROUGH THE
DAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES ACROSS THE CENTRAL
PLAINS. VARIOUS HI-RES MODELS SUGGEST SHOWERS WOULD REACH HIGHWAY
212 AROUND 18Z...AND HIGHWAY 12 BETWEEN 21-0Z THIS AFTERNOON. HAVE
TRIED TO DELAY POPS IN THE NORTHERN AND FAR NORTHEASTERN PORTION
OF THE CWA UNTIL AFTER 21Z. PCPN MAY NOT REACH THE
SISSETON/WHEATON AREA UNTIL AFTER 0Z SUNDAY.
TONIGHT THROUGH SUNDAY MORNING...MODELS SUGGEST THE LOW PRESSURE
SYSTEM WILL MERGE WITH A NORTHERN STREAM TROUGH...WHICH COULD
BRING BETTER CHANCES FOR SHOWERS. THE NORTHERN STREAM WILL LIKELY
BRING GUSTY NORTHWESTERLY WINDS TONIGHT ALONG A SURFACE COLD
FRONT. A FAIRLY DRY AIR MASS WILL FOLLOW THIS COLD FRONT WITH PCPN
LIKELY ENDING FROM WEST TO EAST BY THE MID MORNING HOURS ON
SUNDAY. BY SUNDAY AFTERNOON COLD AIR ADVECTION WILL DEVELOP WITH
GUSTY NORTHWESTERLY WINDS AND INSTABILITY SHOWERS POSSIBLE. WINDS
MAY EXCEED ADVISORY LEVELS...ESPECIALLY IN THE WESTERN HALF OF THE
CWA. A TIGHT PRESSURE GRADIENT OVER THE REGION WILL PROMOTE GUSTY
NORTHWESTERLY WINDS ON MONDAY AS WELL. COLD AIR ALOFT...ALONG WITH
CAPE VALUES AROUND 100 J/KG COULD PRODUCE ISOLATED SHOWERS IN THE
FAR EASTERN PORTION OF THE CWA MONDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 327 AM CDT SAT APR 18 2015
NOT MUCH CHANGE NOTED IN THE LONGER RANGE MODEL OUTPUT...COMPARED
TO 24 HOURS. PRECIPITATION CHANCES ARE PRETTY MUCH DONE AND GONE
MONDAY NIGHT...WITH A MAINLY DRY FORECAST THERE-AFTER /DRY AND
COOL NORTHWEST FLOW ESTABLISHING OVER THE NORTHERN PLAINS ALOFT/.
BY THURSDAY...THERE IS A RATHER SLIM CHANCE THAT ENERGY TRYING
TO LIFT NORTH-NORTHEAST TOWARD THE NORTHERN PLAINS COULD INTRODUCE
SOME DEFORMATION ZONE-FORCED LIGHT PRECIP POTENTIAL ACROSS THE
SOUTHWESTERN FORECAST ZONES...PRIOR TO EXPERIENCING THE SHEARING
EFFECTS OF NORTHWEST /POLAR JET/ FLOW ALOFT. SUPERBLEND CONTINUES
TO PRODUCE SOME LOW PROBABILITIES FOR PRECIPITATION THURSDAY
NIGHT/FRIDAY THOUGH. UNDER THIS NORTHWEST FLOW ALOFT REGIME...LOW
LEVEL FLOW IS PERSISTENTLY ADVECTING COOL/DRY AIR DOWN OUT OF
CANADA ON NORTHEASTERLY BOUNDARY LAYER MIXING WINDS. TEMPERATURES
DURING THE EXTENDED FORECAST PERIOD SHOULD BE RUNNING NEAR NORMAL
TO PERHAPS A FEW DEGREES BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 651 AM CDT SAT APR 18 2015
VFR CONDITIONS ARE EXPECTED THROUGH THE FIRST PART OF TODAY AT
KPIR. HOWEVER A LOW PRESSURE SYSTEM MOVING NORTHEAST WILL SPREAD
SHOWERS AND LOWER /MVFR/ CIGS INTO KPIR BY AROUND
MID-DAY...LASTING WELL INTO TONIGHT BEFORE RELATIVELY LIGHT WINDS
SWITCH AROUND TO THE NORTHWEST AND INCREASE TO 20 TO 30 KNOTS.
VFR CONDITIONS ARE EXPECTED TO HOLD THROUGH LATE THIS
AFTERNOON/EARLY THIS EVENING AT KABR/KMBG/KATY BEFORE THE SHOWERS
AND LOWER /MVFR/ CIGS MOVE IN. LIKE KPIR...KMBG SHOULD SEE
SIMILAR TIMING ON THE CHANGE IN WIND DIRECTION AND SPEED.
HOWEVER...KABR AND KATY PROBABLY WON`T SEE THE ABRUPT SHIFT AND
INCREASE IN WIND SPEEDS UNTIL LATER TONIGHT AT OR AFTER 06Z.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...SD
LONG TERM...DORN
AVIATION...DORN
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
855 AM EDT SAT APR 18 2015
.DISCUSSION...DENSE FOG IS SLOWING LIFTING ACROSS THE AREA THIS
MORNING...HOWEVER...WILL EXTEND ADVISORY UNTIL 14Z (10 AM ET).
MODELS...INCLUDING LATEST HRRR MODEL...SHOWS UPSLOPE FLOW INTO THE
SPINE OF SOUTHERN APPALACHIANS THIS AFTERNOON. MARGINAL INSTABILITY
WILL ALLOW SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP ACROSS THE
MOUNTAINS...THEN SPREADING INTO THE VALLEY. BEST COVERAGE...DUE TO
BETTER INSTABILITY...WILL BE ACROSS THE CENTRAL AND SOUTHERN
MOUNTAINS AND SOUTHWEST NORTH CAROLINA. HAVE INCREASE CHANCES FOR
CONVECTION AREA-WIDE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 76 62 76 61 / 40 100 90 60
KNOXVILLE MCGHEE TYSON AIRPORT, TN 78 61 76 61 / 40 100 90 60
OAK RIDGE, TN 77 62 75 60 / 30 100 90 60
TRI CITIES AIRPORT, TN 80 58 75 56 / 30 70 90 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CHEROKEE-
CLAY.
TN...DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
ANDERSON-BLEDSOE-BLOUNT SMOKY MOUNTAINS-BRADLEY-CAMPBELL-
CLAIBORNE-COCKE SMOKY MOUNTAINS-EAST POLK-GRAINGER-HAMBLEN-
HAMILTON-HANCOCK-HAWKINS-JEFFERSON-JOHNSON-KNOX-LOUDON-
MARION-MCMINN-MEIGS-MORGAN-NW BLOUNT-NORTH SEVIER-NORTHWEST
CARTER-NORTHWEST COCKE-NORTHWEST GREENE-NORTHWEST MONROE-
RHEA-ROANE-SCOTT TN-SEQUATCHIE-SEVIER SMOKY MOUNTAINS-
SOUTHEAST CARTER-SOUTHEAST GREENE-SOUTHEAST MONROE-SULLIVAN-
UNICOI-UNION-WASHINGTON TN-WEST POLK.
VA...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR LEE-RUSSELL-
SCOTT-WASHINGTON-WISE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
941 AM CDT SAT APR 18 2015
.UPDATE...
MORNING UPPER AIR DATA AND SHORT-TERM MODEL GUIDANCE HAS
IDENTIFIED A SHORTWAVE TROUGH THAT IS PIVOTING AROUND THE UPPER
LOW OVER COLORADO. THIS SHORTWAVE WILL TRACK THROUGH TEXAS THIS
AFTERNOON AND EVENING. A DRY LINE IS FORECAST TO SET UP JUST WEST
OF THE CWA BORDER THIS AFTERNOON AND WILL BECOME THE FOCUS FOR
SCATTERED CONVECTION WHEN FORCING FROM THE SHORTWAVE TROUGH
ARRIVES. CONVECTIVE INITIATION SHOULD START AFTER 3 PM JUST WEST
OF THE CWA...WITH THESE STORMS MOVING/DEVELOPING GRADUALLY
NORTHEASTWARD INTO AND THROUGH THE CWA DURING THE LATE AFTERNOON
AND EVENING HOURS. GIVEN THE EXPECTED TIMING...HAVE LOWERED THE
POPS ALONG AND EAST OF I-35 FOR THE TODAY PERIOD AS ANY
RAIN/STORMS SHOULD HOLD OFF UNTIL THIS EVENING FOR THESE AREAS.
THERE IS A LACK OF LOW LEVEL WIND FLOW EVIDENT IN THE MORNING
DATA AND THE AIRMASS HAS BEEN FAIRLY WORKED OVER BY THE CONVECTION
FROM YESTERDAY AND LAST NIGHT. HOWEVER THE APPROACH OF THE
SHORTWAVE TROUGH WILL HELP TURN WINDS TO THE SOUTH BY THE
AFTERNOON...THEREBY INCREASING MOISTURE/THETA-E ADVECTION AND BULK
SHEAR VALUES ACROSS NORTH TEXAS. TEMPERATURES WILL ALSO WARM INTO
THE UPPER 70S AND LOWER 80S OVER NORTH TEXAS TODAY...WHICH WILL
YIELD GENERALLY 1000-2000 J/KG OF SURFACE BASED CAPE. THUS THE
AIRMASS SHOULD BE RECHARGED JUST ENOUGH TO SUPPORT SCATTERED
CONVECTION WITH A POTENTIAL FOR SEVERE WIND AND HAIL...ESPECIALLY
WEST OF I-35 IN THE LATE AFTERNOON HOURS. THE SEVERE THREAT WILL
DIMINISH AS THE STORMS HEAD EAST OF I-35 DUE TO THE LOSS OF
HEATING AND INCREASING CINH.
TR.92
&&
.AVIATION...
/ISSUED 707 AM CDT SAT APR 18 2015/
/12Z TAFS/
PREVIOUS RAINFALL AND LIGHT WINDS HAVE MADE THE TAFS QUITE
CHALLENGING THROUGH THE FIRST 3-6 HRS OF THE FORECAST. TO ADD TO
THE MIX...SUBSIDENCE AND SOME PARTIAL BREAKS IN THE MULTIPLE
LAYERS OF CLOUDS ARE CAUSING VSBYSO FLUCTUATE FROM P6SM TO 1/4SM
IN FOG FROM THE TAF SITES AND AREAS TO THE WEST. WILL CARRY
PREVAILING MVFR VSBYS W/TEMPO IFR-VLIFR VSBYS IN SHALLOW GROUND
FOG THROUGH LATE MORNING. AS WARMING TEMPERATURES AND STRONGER SE
WINDS ARRIVE BY MIDDAY...LOOK FOR VFR CIGS TO PREVAIL.
AN UPPER LOW OVER COLORADO WILL DRIFT OVER THE HIGH PLAINS OF
WESTERN KS BY TONIGHT. ANOTHER STORM CLUSTER WILL FORM OFF THE
WEST TX DRYLINE LATE THIS AFTERNOON AND MIGRATE EWD TOWARD I-35
AND THE TAF SITES IN THE 23Z-04Z TIME FRAME ONCE AGAIN. HAVE
BROUGHT STORMS IN AN HOUR SOONER AT AFW/FTW...BUT OTHERWISE WILL
CARRY A 2-HR TEMPO GROUP FOR THE HIGHEST CONFIDENCE TIMING FOR
TSRA WITH MVFR CIGS/CB. WITH THE UPPER LOW FURTHER EAST COMPARED
TO THE SAME TIME LAST NIGHT...WE DO NOT EXPECT THE CONVECTIVE
COMPLEX TO HANG AROUND QUITE AS LONG THROUGH 06Z LIKE FRIDAY
EVENING.
WE EXPECT LIGHT N/NE TO VRB SURFACE WINDS UNDER 5 KTS THROUGH
MID-LATE MORNING. THE ENVIRONMENTAL FLOW SHOULD TAKES OVER WITH
S/SE WINDS NEAR 10 KTS DURING AFTERNOON...BECOMING SOUTHERLY 5-10
KTS OVERNIGHT. IT/S HIGHLY POSSIBLE THAT THIS FLOW WILL BE DISTURBED
BY CONVECTIVE OUTFLOW ONCE AGAIN WITH DIFFERING DIRECTIONS AND
SPEEDS...BUT THAT WILL NEED TO BE ADDRESSED ON LATER TAFS WHEN
CONFIDENCE IS HIGHER.
MORE MVFR/IFR CONDITIONS MAY RETURN SUNDAY MORNING...BUT SHOULD
OCCUR MAINLY AFTER 12Z AND BEYOND THIS TAF CYCLE.
05/
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 18 2015/
THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS
BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE
OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL
STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO
NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH
WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL
SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE
NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS
SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE
BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR
FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW...
THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF
SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF
THE BOUNDARY TODAY.
THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS
STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING
DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS
MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST
ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE
PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR
WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE
SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE
DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE
STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH
TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE
STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH
AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS
WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE
TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX
COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT
TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE
HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD
REAGGRAVATE FLOODING ISSUES.
AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE
A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS
EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL
FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY
FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE
THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL
ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE
AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION
BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY
AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT...
AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP
INTO THE 40S MONDAY AND TUESDAY MORNING.
ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE
EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT
AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO
SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING
RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY.
EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH
UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS
THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE
NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS
IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY
PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP
TEMPERATURES CLOSER TO CLIMATOLOGY.
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 60 80 53 73 / 20 50 10 5 5
WACO, TX 80 60 83 53 75 / 20 50 10 5 5
PARIS, TX 75 58 77 50 70 / 20 40 20 5 0
DENTON, TX 77 57 79 49 72 / 30 50 10 5 5
MCKINNEY, TX 78 58 79 51 73 / 20 50 10 5 0
DALLAS, TX 80 62 81 54 74 / 20 50 10 5 5
TERRELL, TX 78 60 80 52 74 / 20 50 10 5 5
CORSICANA, TX 79 61 82 52 75 / 20 50 20 5 5
TEMPLE, TX 79 60 84 53 74 / 20 50 10 5 5
MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
707 AM CDT SAT APR 18 2015
.AVIATION...
/12Z TAFS/
PREVIOUS RAINFALL AND LIGHT WINDS HAVE MADE THE TAFS QUITE
CHALLENGING THROUGH THE FIRST 3-6 HRS OF THE FORECAST. TO ADD TO
THE MIX...SUBSIDENCE AND SOME PARTIAL BREAKS IN THE MULTIPLE
LAYERS OF CLOUDS ARE CAUSING VSBYSO FLUCTUATE FROM P6SM TO 1/4SM
IN FOG FROM THE TAF SITES AND AREAS TO THE WEST. WILL CARRY
PREVAILING MVFR VSBYS W/TEMPO IFR-VLIFR VSBYS IN SHALLOW GROUND
FOG THROUGH LATE MORNING. AS WARMING TEMPERATURES AND STRONGER SE
WINDS ARRIVE BY MIDDAY...LOOK FOR VFR CIGS TO PREVAIL.
AN UPPER LOW OVER COLORADO WILL DRIFT OVER THE HIGH PLAINS OF
WESTERN KS BY TONIGHT. ANOTHER STORM CLUSTER WILL FORM OFF THE
WEST TX DRYLINE LATE THIS AFTERNOON AND MIGRATE EWD TOWARD I-35
AND THE TAF SITES IN THE 23Z-04Z TIME FRAME ONCE AGAIN. HAVE
BROUGHT STORMS IN AN HOUR SOONER AT AFW/FTW...BUT OTHERWISE WILL
CARRY A 2-HR TEMPO GROUP FOR THE HIGHEST CONFIDENCE TIMING FOR
TSRA WITH MVFR CIGS/CB. WITH THE UPPER LOW FURTHER EAST COMPARED
TO THE SAME TIME LAST NIGHT...WE DO NOT EXPECT THE CONVECTIVE
COMPLEX TO HANG AROUND QUITE AS LONG THROUGH 06Z LIKE FRIDAY
EVENING.
WE EXPECT LIGHT N/NE TO VRB SURFACE WINDS UNDER 5 KTS THROUGH
MID-LATE MORNING. THE ENVIRONMENTAL FLOW SHOULD TAKES OVER WITH
S/SE WINDS NEAR 10 KTS DURING AFTERNOON...BECOMING SOUTHERLY 5-10
KTS OVERNIGHT. IT/S HIGHLY POSSIBLE THAT THIS FLOW WILL BE DISTURBED
BY CONVECTIVE OUTFLOW ONCE AGAIN WITH DIFFERING DIRECTIONS AND
SPEEDS...BUT THAT WILL NEED TO BE ADDRESSED ON LATER TAFS WHEN
CONFIDENCE IS HIGHER.
MORE MVFR/IFR CONDITIONS MAY RETURN SUNDAY MORNING...BUT SHOULD
OCCUR MAINLY AFTER 12Z AND BEYOND THIS TAF CYCLE.
05/
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 18 2015/
THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS
BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE
OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL
STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO
NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH
WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL
SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE
NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS
SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE
BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR
FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW...
THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF
SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF
THE BOUNDARY TODAY.
THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS
STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING
DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS
MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST
ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE
PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR
WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE
SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE
DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE
STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH
TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE
STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH
AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS
WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE
TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX
COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT
TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE
HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD
REAGGRAVATE FLOODING ISSUES.
AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE
A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS
EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL
FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY
FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE
THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL
ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE
AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION
BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY
AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT...
AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP
INTO THE 40S MONDAY AND TUESDAY MORNING.
ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE
EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT
AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO
SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING
RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY.
EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH
UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS
THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE
NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS
IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY
PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP
TEMPERATURES CLOSER TO CLIMATOLOGY.
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 60 80 53 73 / 40 50 10 5 5
WACO, TX 80 60 83 53 75 / 40 50 10 5 5
PARIS, TX 75 58 77 50 70 / 50 40 20 5 0
DENTON, TX 77 57 79 49 72 / 40 50 10 5 5
MCKINNEY, TX 78 58 79 51 73 / 40 50 10 5 0
DALLAS, TX 80 62 81 54 74 / 40 50 10 5 5
TERRELL, TX 78 60 80 52 74 / 40 50 10 5 5
CORSICANA, TX 79 61 82 52 75 / 40 50 20 5 5
TEMPLE, TX 79 60 84 53 74 / 40 50 10 5 5
MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
631 AM CDT Sat Apr 18 2015
.AVIATION...
/12Z TAFS/
Two upper level disturbance will bring a round of storms to most
TAF sites this morning and again this afternoon. Latest radar data
is showing an area of storms moving east and northeast towards
KSOA and KJCT and could reach those sites between 12Z and 15Z.
Main impacts will be gusty winds, brief heavy rain, lightning and
low visibilities. The IFR Cigs should gradually improve to VFR shortly
after 15Z. The next round of storms may form along the dryline
after 18Z at KSOA, KBBD and KJCT. A few of these may become severe
and produce large hail, damaging winds and very heavy rainfall.
&&
.PREV DISCUSSION... /ISSUED 420 AM CDT Sat Apr 18 2015/
SHORT TERM...
(Today and Tonight)
There is a threat for severe thunderstorms across the eastern half
of West Central Texas today as an upper level trough associated with
the upper low near the Four Corners moves across the region. The
main threats will be large hail and damaging winds. SPC has placed
much of the area east of the dryline in a slight risk for severe
thunderstorms today.
Latest radar is showing showers developing across the mountains in
northern Mexico, south of Sanderson, in association with the next
approaching shortwave as can be seen on water vapor satellite
imagery. This could bring a round of showers and thunderstorms to
West Central Texas this morning before the main upper trough moves
across later this afternoon.
The dryline is forecast to move east today as the RUC model progs
this front from Haskell to just east of San Angelo to Sonora by
early evening. This dryline should trigger scattered thunderstorms
this afternoon as the following ingredients come together: dewpoints
ranging from the upper 50s to the lower 60s, moderate 0-6km shear,
MU CAPE Values 1500-2000 J/KG, a weak capping inversion, approaching
upper trough and a right rear entrance region of the southern stream
upper level jet flowing across the area. These parameters should
set the stage for the development of a few supercells today,
resulting in large hail and damaging winds. These storms may
continue into the early evening hours before dissipating.
Highest Pops were placed across the Northwest Hill Country extending
north to Brownwood. Went closer to the warmer MAV MOS for
temps as the dry warm air invades the western part of the region
today.
26
LONG TERM...
(Sunday through Friday)
Cold front will move through Sunday. Dry southwest to west winds
ahead of the front will not only preclude rain chances, but also
give a boost to temperatures, being downslope compression. Still,
cold advection will bring cooler temperatures Sunday, with highs
in the 70s.
Isolated dryline thunderstorms possible mid and late week. West
Central Texas will be under a broad upper ridge, so widespread
showers or thunderstorms not expected. Could see a few highs
approach 90s, especially Wednesday and Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 82 55 79 49 72 / 30 20 5 5 5
San Angelo 84 54 82 50 75 / 30 10 5 5 5
Junction 82 56 85 52 75 / 50 30 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
26/99/99
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
611 AM CDT SAT APR 18 2015
.AVIATION...
CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND
CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON.
CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE
FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING
CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST
LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS
MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON
HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST
OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE
TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS
FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT
IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS
MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN
EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY
AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL
LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18
HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE
EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE
WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND
WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE
FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS
SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO
-10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT
DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC
DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE
EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER
A SLIGHT RISK OF SEVERE THUNDERSTORMS.
HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF
STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE
SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND
MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING
STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE
EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP
CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR
TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS
ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS
EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW
PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH
MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE
WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT
AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY
AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT
WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT
TEMPS INTO THE 50S AREAWIDE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS
AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY.
SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR
SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY
AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - -
AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - -
NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - -
BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - -
DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10
GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - -
HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - -
SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - -
LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10
SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - -
STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...29
SYNOPTIC/GRIDS...17
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
612 AM CDT SAT APR 18 2015
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.UPDATE...
ISSUED AT 407 AM CDT SAT APR 18 2015
AFTER FURTHER COORDINATION WITH ARX AND THE DNR...WILL ISSUE A RED
FLAG WARNING FOR WOOD COUNTY. THE COMBO OF HUMIDITIES FALLING NEAR
20 PCT THIS AFTERNOON...MAX TEMPS IN THE 60S...WIND SPEEDS OF 10
TO 20 MPH...AND DRY FUELS WILL LEAD TO A CRITICAL FIRE WEATHER DAY
THERE. THIS RED FLAG WARNING WILL TARGET THE PINE COUNTRY OF
CENTRAL WISCONSIN.
ADDITIONALLY...THE COLD FRONT HAS JUST PASSED OVER GREEN BAY.
WINDS HAVE SHIFTED TO THE NORTH AND ARE GUSTING TO 22 KNOTS AT THE
GRB AIRPORT. SOME GUSTS UP TO 25 KNOTS OVER THE BAY ARE ALSO OCCURRING.
&&
.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY
POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE
CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH
IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS
OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN
EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME
GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO
SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS
ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE
WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY.
TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF
NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY
MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY
DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY.
THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY
AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO
THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS
AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE
TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL
WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED
SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A
FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD
HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS
IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES
UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM
WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND
LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND
CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL
HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT
OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS.
LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST.
SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE
WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO
WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW
SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL
IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF
LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW
LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE
AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT
BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST
WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE
WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO
LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO
WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN
GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN
CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK.
THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A
CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS.
RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE
SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL
BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY
POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT
LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF
SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF
WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION.
MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL
RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE
IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME
OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD
TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND
WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN
THE FORECAST.
AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW
AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING
CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING
OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF
SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY
THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 610 AM CDT SAT APR 18 2015
A COLD FRONT HAS MOVED THROUGH THE REGION...SHIFTING
WINDS TO THE NORTHEAST. THESE NE WINDS WILL BE GUSTY AT TIMES TODAY
OVER CENTRAL AND NORTHEAST WISCONSIN. THE GUSTINESS WILL DIMINISH
THIS EVENING...BUT WILL SEE THICKENING AND LOWERING CLOUDS THROUGH
THE NIGHT. RAIN WILL LIKELY HOLD OFF AT THE TAF SITES UNTIL
SUNDAY MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM CDT THIS
EVENING FOR WIZ035.
&&
$$
UPDATE.........MPC
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
551 AM MDT SAT APR 18 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT SAT APR 18 2015
TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL
COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL
MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING
WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT
UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE
OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM
WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY
WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL
IMPACTS TO TRAVEL.
TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM
SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH
DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES.
SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT
AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR
NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY
CONDITIONS ELSEWHERE.
SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES
PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR
SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 415 AM MDT SAT APR 18 2015
THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END
POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE
ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD
BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY
RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN
COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF
BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES
AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF
THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON
THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS.
WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A
SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM
ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE
BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT
WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE
AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS
LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 545 AM MDT SAT APR 18 2015
THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF
THE LARAMIE RANGE AND MOVING WESTWARD. EXPECT IFR CONDITIONS AND LIGHT
SNOW THROUGH MUCH OF THE MORNING TO THE WEST OF THE LARAMIE RANGE.
IFR CIGS ARE EXPECTED THROUGH MID MORNING AT CYS BUT PRECIPITATION
HAS ENDED. MVFR CONDITIONS WILL GENERALLY PREVAIL THROUGH 18Z
OVER THE NEBRASKA PANHANDLE WITH PERIODS OF LIGHT
RAIN...ESPECIALLY OVER THE NORTHERN PANHANDLE. A COLD FRONT WILL
PUSH ACROSS THE PLAINS BY LATE THIS EVENING (AFTER 03Z) WITH
BREEZY NORTH WINDS.
&&
.FIRE WEATHER...
ISSUED AT 402 AM MDT SAT APR 18 2015
NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD
PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL NOON MDT TODAY FOR WYZ114>117.
WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ103-105-106-
110-112.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION...DELAYED
NWS CHEYENNE WY
426 AM MDT SAT APR 18 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT SAT APR 18 2015
TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL
COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL
MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING
WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT
UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE
OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM
WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY
WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL
IMPACTS TO TRAVEL.
TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM
SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH
DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES.
SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT
AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR
NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY
CONDITIONS ELSEWHERE.
SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES
PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR
SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 415 AM MDT SAT APR 18 2015
THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END
POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE
ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD
BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY
RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN
COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF
BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES
AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF
THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON
THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS.
WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A
SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM
ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE
BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT
WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE
AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS
LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1155 PM MDT FRI APR 17 2015
WIDESPREAD IFR/LIFR CONDITIONS THROUGH THE MORNING. A LARGE AREA
OF RAIN IS CURRENTLY OVER THE PANHANDLE AND WILL MOVE TO AROUND
THE LARAMIE RANGE BY 12Z. WITH COLDER TEMPS ACROSS WY...EXPECT
LOWER VIS IN LIGHT SNOW. PERIODS OF SNOW WILL BE LIKELY ACROSS WY
THROUGH THE EARLY AFTN.
&&
.FIRE WEATHER...
ISSUED AT 402 AM MDT SAT APR 18 2015
NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD
PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL NOON MDT TODAY FOR WYZ114>117.
WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ103-105-106-
110-112.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
328 PM MDT SAT APR 18 2015
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 325 PM MDT SAT APR 18 2015
THE LOW PRESSURE RESPONSIBLE FOR THE MUCH NEEDED PRECIP OVER THE
LAST FEW DAYS IS NOW LOCATED OVER THE FRONT PLAINS WHILE CYCLONIC
FLOW CONTINUES TO PUMP IN MOISTURE FROM THE NORTH TO SOUTH. THIS
FLOW STARTS IN NERN WY AND THE PLUME REACHES AS FAR SOUTH AS THE
SAN JUANS. SNOW AND RAIN HAS FALLEN MUCH OF THE DAY UNDER THIS
PLUME OF MOISTURE AND WILL CONTINUE TO DO SO THROUGH THIS EVENING.
CURRENT WINTER HIGHLIGHTS LOOK GOOD SO NO CHANGES THERE. AN UPPER
LEVEL DISTURBANCE OVER SRN CANADA IS TRAILING A TROUGH THAT IS
CAUSING THE AREA OF LOW PRESSURE TO KEEP MOVING EWRD. THE REASON
THIS IS HAPPENING SO SLOWLY IS THE LACK OF ANY STRONG JET FEATURES
TO REALLY GET THIS SYSTEM MOVING. EVEN SO...THE CLOUD SHIELD/PLUME
WILL BRING MORE PRECIP TO THE AREA AS THE ATTENDANT LOW PRESSURE
MEANDERS EAST. BY MIDNIGHT...PRECIP WILL FAVOR THE NRN AND CENTRAL
MTNS ALONG WITH THE FLATTOPS DUE TO THEIR FAVORABLE LOCATION SO
ADDITIONAL ACCUMULATIONS STILL POSSIBLE UP THERE. THE REST OF THE
CWA MAY SEE AN ODD SHOWER OR TWO BUT NOTHING TOO SIGNIFICANT.
BY SUNDAY...THE CANADIAN LOW WILL BE JUST TO THE NORTH OF
MINNESOTA WHILE HIGH PRESSURE BUILDS INTO THE PACNW. THIS WILL
CAUSE OUR CWA TO BE SANDWICHED BETWEEN THESE TWO FEATURES. WEAK
PIECES OF ENERGY WILL DROP DOWN FROM THE NW POSSIBLY CAUSING SOME
PRECIP FOR THE CWA. THE GFS HIGHLIGHTING TWO DISTINCT WAVES...ONE
SUNDAY EVENING AND ANOTHER MONDAY MORNING. THE NAM12 ONLY SHOWING
SOME SPOTTY SHOWERS AT BEST WITH SOME CONVECTION THROWN IN. THE
HRRR AND RAP SHOWING MUCH LESS IN THE WAY OF PRECIP. THIS ALL
MEANS UNSETTLED WX WILL CONTINUE BUT WITH MUCH MORE DEFINITIVE
BREAKS BETWEEN DISTURBANCES. FORECAST BRINGS MOSTLY BENIGN
WEATHER SUNDAY WITH INCREASING CHANCES FOR PRECIP FROM
MIDAFTERNOON ONWARDS...MAINLY FAVORING THE CONTINENTAL DIVIDE.
TEMPS WILL WARM UP CONSIDERABLY TOMORROW THOUGH STILL REMAIN 5 TO
10 DEGREES BELOW NORMAL.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 325 PM MDT SAT APR 18 2015
UNSETTLED NW FLOW IS EXPECTED MONDAY AND TUESDAY. AN EMBEDDED WAVE
SHOULD FOCUS THE BEST CHANCE OF SHOWERS OVER THE NORTHERN AND
CENTRAL MOUNTAINS MONDAY AFTERNOON AND EVENING. DAYTIME INSTABILITY
WILL KEEP ISOLATED TO SCATTERED SHOWERS OVER THE MTNS ON TUESDAY.
TEMPORARY RIDGING DEVELOPS OVER THE AREA BY MIDWEEK AS A TROUGH
FORMS ALONG THE WEST COAST...WITH AN UPPER LOW OVER SRN CA BY THU
MORNING. ENOUGH RESIDUAL MOISTURE LINGERS FOR A FEW AFTERNOON
SHOWERS OR THUNDERSTORMS. FLOW ALOFT BECOMES SOUTHWEST...AND THE
SRN CA LIFTS ACROSS THE FOUR CORNERS/DESERT SOUTHWEST THU NIGHT
AND FRI MORNING. TIMING AND TRACK A BIT DIFFERENT BETWEEN MODELS
BUT STILL LOOKING LIKE A BETTER CHANCE OF PRECIPITATION WITH SOME
THUNDERSTORMS LATE NEXT WEEK. BOOSTED POPS FOR THU AFTERNOON
THROUGH FRI OVER THE BLENDED FORECAST GUIDANCE AS A RESULT.
GFS AND ECMWF SOLUTIONS CONTINUE TO DIVERGE ON SATURDAY. ECWMF MORE
AMPLIFIED AS IT DIGS A PAC NW TROUGH TO THE SRN GREAT BASIN BY
SATURDAY...RESULTING IN DOWNSTREAM RIDGING AND SW FLOW OVER OUR
AREA. GFS DROPS SOME ENERGY FROM THE PAC NW TROUGH DOWN THE WEST
COAST BUT SENDS MORE OF IT ACROSS THE NRN ROCKIES WITH WESTERLY FLOW
ACROSS UT/CO. WILL FOLLOW THE BLENDED GUIDANCE FOR SAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1137 AM MDT SAT APR 18 2015
WIDESPREAD MVFR/IFR WILL CONTINUE FOR MUCH OF THE DAY AS LOW
CLOUDS AND PRECIP STREAM DOWN FROM THE NORTHWEST. KCNY AND
KVEL...AND KDRO WILL SLOWLY IMPROVE THROUGH THE DAY AS THE LOW
OVER THE FRONT RANGE CONTINUES TO DRIFT EASTWARD. REMAINING TAF
SITES WILL SEE THE PRECIP AND CIGS THROUGH 06Z WITH CONDITIONS
SLOWLY IMPROVING AFTER THAT. OCCNL LULLS ARE POSSIBLE HOWEVER. ALL
HIGHER TERRAIN WILL BE OBSCURED TODAY. NO CONCERNS WITH WINDS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR COZ009-010-
012-017-018.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ003-
004-013.
UT...NONE.
&&
$$
SHORT TERM...TGR
LONG TERM...JAD
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
322 PM MDT SAT APR 18 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 322 PM MDT SAT APR 18 2015
UPPER LEVEL LOW HAS MADE VERY LITTLE EASTWARD PROGRESS TODAY AND
IS STILL LOCATED OVER SOUTHWEST WASHINGTON COUNTY...BASED ON THE
RECENT MOTION OF RADAR ECHOES. AFTERNOON HEATING AND COLD
TEMPERATURES ALOFT HAVE DE-STABILIZED THE AIRMASS ENOUGH FOR
EMBEDDED THUNDERSTORMS TO DEVELOP OVER THE FAR NORTHEAST PLAINS.
MOUNTAIN AREAS HAVE BEEN PICKING UP SCATTERED SNOW SHOWERS...BUT
NOT MUCH NEW SNOW ACCUMULATION...BASED ON WEB CAMERAS AND SNOTEL
DATA.
THE SHOWERS AND THUNDERSTORMS THIS EVENING SHOULD TAPER IN THE
EVENING...WITH THE LOSS OF DAYTIME HEATING. ADDITIONAL SHOWERS ARE
EXPECTED OVERNIGHT AS THE UPPER LOW MOVES EASTWARD AND THE RETURN
FLOW ON THE BACKSIDE OF THE LOW MOVES OUT OF THE MOUNTAINS AND
ACROSS THE PLAINS. THE NAM AND RAP FORECASTS HAVE RAIN OCCURRING
THROUGH MOST OF THE NIGHT AND THEN A DECREASE IN SHOWER ACTIVITY
BY MIDDAY SUNDAY. TEMPERATURES OVERNIGHT WILL DROP TO THE MID AND
UPPER 30S ON THE PLAINS WHICH MAY BE COOL ENOUGH FOR SOME SNOW TO
FALL. NO SIGNIFICANT ACCUMULATIONS ARE EXPECTED THOUGH. SUNDAY
WILL BE A MIX OF MORNING SHOWERS AND THEN DECREASING CLOUDS IN THE
AFTERNOON. STRONG INSOLATION SHOULD ALLOW AFTERNOON TEMPERATURES
TO CLIMB INTO THE LOWER 50S. MOUNTAIN AREAS COULD SEE SCATTERED
SNOW SHOWERS CONTINUE AS WE REMAIN UNDER MOIST NORTHWESTERLY FLOW.
SNOW ACCUMULATIONS SHOULD BE LESS THAN 3 OR 4 INCHES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 322 PM MDT SAT APR 18 2015
A COLD NORTHWEST FLOW ON THE BACK SIDE OF EXITING
LONG WAY UPPER TROUGH DRIVES A CLIPPER TYPE DISTURBANCE SOUTHWARD
OUT OF WYOMING SUNDAY NIGHT AND MONDAY MORNING ACCORDING TO
DETERMINISTIC MODELS. SYSTEM APPEARS TO PACK ADJACENT COLD
AIR...MOISTURE AND OROGRAPHIC LIFT TO PRODUCE ANOTHER ROUND OF LIGHT
SNOW ACCUMULATION IN THE HIGHER MTN RANGES. MTN PASSES AND EXPOSED
NORTHWEST SLOPES COULD SEE ANYWHERE FROM 2-5 INCHES OF ADDITIONAL
SNOW ACCUMULATION BY MONDAY EVENING. WETBULB TEMP IS PROGGED TO BE
LOW ENOUGH FOR A RAIN/SNOW MIX ON THE NEAR BY PLAINS SUNDAY
EVENING...AND POSSIBLY ALL SNOW LATE SUNDAY NIGHT INTO MONDAY
MORNING. THIS SYSTEM DOES NOT LOOK LIKE A BIG PRECIP MAKER FOR THE
PLAINS AND ANY SNOW THAT FALLS AT LOWER ELEVATIONS SHOULD NOT
ACCUMULATE.
MODELS SHOW THIS DISTURBANCE QUICKLY MOVING OUT OF THE FCST AREA
DURING THE DAY MONDAY AND WITH LOW LEVEL WINDS TURNING WESTERLY...
TEMPS SHOULD MANAGE TO REACH THE 50S ON THE PLAINS WITH SUNSHINE
RETURNING LATE IN THE DAY.
MODELS SHOW A BREAK IN THE COOL AND WET NWLY FLOW PATTERN TUESDAY
INTO WEDNESDAY WHEN A DIRTY SHORTWAVE UPPER RIDGE OVER THE GREAT
BASIN WORKS ITS WAY ACROSS COLORADO. GFS AND NAM INDICATE A FAIR
AMOUNT OF MID AND HIGH LEVEL MOISTURE WITH THIS RIDGE...SUFFICIENT
TO WARRANT A CHANCE OF RAIN/SNOW SHOWERS IN THE HIGH COUNTRY ON
TUESDAY AND AGAIN BY WEDNESDAY AFTERNOON. LATE DAY SHOWERS ON
WEDNESDAY COULD BE ACCOMPANIED BY SOME THUNDER DURING THE WARMEST
TIME OF THE DAY. ON THE PLAINS...DRY CONDITIONS WILL PREVAIL WITH A
PREVAILING W-SWLY LOW LEVEL FLOW. AS A RESULT...TEMPS REBOUND WITH
AFTN READINGS 1-5 DEG F ABOVE AVERAGE ON TUES AND 5-10 DEG ABOVE
AVERAGE BY WED. LATE ON WEDNESDAY UPPER RIDGE OVER COLORADO APPEARS
TO FLATTEN OUT WITH MODELS SHOWING A WEAK SHORTWAVE TROUGH ZOOMING
UP FROM THE DESERT SOUTHWEST AND THEN ROUNDING THE TOP OF RIDGE.
SHOULD THIS HAPPEN...CAN SEE PRECIP CHANCES ON THE RISE AGAIN ACRS
THE CWA WITH RAIN/SNOW IN THE HIGH COUNTRY AND RAIN SHOWERS ON THE
PLAINS. THERE/S ALSO A SLIGHT CHANCE OF T-STORMS BY EVENING.
THURSDAY AND BEYOND...LARGE SCALE FLOW PATTERN OVER THE WESTERN
CONUS IS PROGGED TO BECOME MORE LIVELY WITH YET ANOTHER LARGE SCALE
UPPER TROUGH MAKING ITSELF FELT IN THE GREAT BASIN WEDNESDAY INTO
THURSDAY AND ACROSS THE NORTH CENTRAL AND NORTHEAST THURSDAY AND
FRIDAY. WITH AS MUCH MOISTURE AND COOL AIR WITH THIS SYSTEM...WILL
CONTINUE LOW POPS FOR ALL AREAS RIGHT THROUGH SATURDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 00Z SUNDAY LATE AFTERNOON)
ISSUED AT 322 PM MDT SAT APR 18 2015
SHOWER ACTIVITY IS EXPECTED TO CONTINUE MOVING INTO THE DENVER
AREA FROM THE NORTH THROUGH EARLY THIS EVENING. ISOLATED
THUNDERSTORMS WILL BE POSSIBLE ALONG WITH BRIEF HEAVY RAIN AND
GUSTY WINDS. THE THREAT OF THUNDER WILL CONTINUE THROUGH ABOUT 8
PM MDT. ADDITIONAL RAIN SHOWERS ARE EXPECTED OVERNIGHT AS THE
UPPER LEVEL SYSTEM EXITS THE STATE...DRAGGING AN AREA OF MOIST AIR
BEHIND IT. SHOWER ACTIVITY WILL MOVE OUT OF THE NORTH THROUGH THE
OVERNIGHT HOURS AND MAY MIX WITH SNOW AT TIMES. NO SIGNIFICANT
ACCUMULATIONS ARE ANTICIPATED. SHOWER ACTIVITY WILL BE TAPERING
OFF TOMORROWWITH IMPROVING CONDITIONS THROUGH THE AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DANKERS
LONG TERM...BAKER
AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1023 AM MDT SAT APR 18 2015
.UPDATE...
ISSUED AT 1023 AM MDT SAT APR 18 2015
NOT MANY CHANGES TO THE FORECAST AT THIS TIME. THE CENTER OF THE
UPPER LOW HAS MOVED OVER LINCOLN COUNTY WITH A VORTICITY CENTER
HELPING TO KICK OFF SHOWERS AND A FEW THUNDERSTORMS EARLIER THIS
MORNING. AS THE VORTICITY CENTER CONTINUES ROTATING OVER THE
PLAINS...IT WILL COMBINE WITH SOME DAYTIME HEATING TO CONTINUE
PRODUCING SHOWERY ACTIVITY THAT MAY EVENTUALLY MAKE IT BACK TO THE
FOOTHILLS. ANOTHER BAND OF MOISTURE IN THE DEFORMATION REGION TO
THE NORTHWEST OF THE UPPER LOW WILL CONTINUE ROTATING INTO THE
NORTHERN MOUNTAINS THROUGH THE AFTERNOON. ADDITIONAL ACCUMULATING
SNOWFALL SHOULD CONTINUE THROUGH MUCH OF THE DAY WITH AMOUNTS UP
TO A FEW INCHES POSSIBLE. LATE MORNING FORECAST UPDATE WILL
CONTAIN ONLY MINOR CHANGES...CHIEFLY ADDING THE MENTION OF
ISOLATED AFTERNOON THUNDERSTORMS TO THE PLAINS THROUGH THE LATE
MORNING AND AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 512 AM MDT SAT APR 18 2015
UPPER LOW NEAR WALSENBURG AT THIS TIME TRACKING SLOWLY EAST. DRY
SLOT HAS CURLED AROUND ACROSS MOST OF EASTERN COLORADO WITH
MOISTURE WRAPPING BACK FROM WYOMING INTO THE COLORADO MOUNTAINS.
AT THIS TIME THE BACK PART OF THIS SYSTEM DOES NOT HAVE STRONG
LIFT WITH IT...BUT THIS IS EXPECTED TO INCREASE DURING THE DAY AS
EVERYTHING CONTINUES TO SPIN AROUND THE LOW CENTER MOVING SLOWLY
EAST. A COMPLEX PATTERN...BUT THE GOOD NEWS IS THE MODELS HAVE
PRETTY GOOD AGREEMENT ON THE BIG PICTURE. DETAILS OF JUST WHERE
THE BANDING STRUCTURE AND CONVECTION ARE VARY CONSIDERABLY. LIKING
THE HRRR PRESENTATION OF THE DEVELOPING BACK EDGE SNOW BAND ACROSS
THE MOUNTAINS...ROUGHLY FROM LARAMIE TOWARD RIFLE THIS MORNING.
HARD TO SAY IF THE NORTH CENTRAL MOUNTAINS WILL BE IN THE BEST OF
THIS...OR IF IT WILL STAY FURTHER WEST WITH THE DRIER AIR CURLING
BACK OVER THE FRONT RANGE. I DID INCREASE THE POPS FOR THE
MOUNTAINS...HELD OFF ON INCREASING AMOUNTS TOO MUCH AS THE SNOW
MAY TEND TOWARD LIGHT SHOWERS IN THE VALLEYS WITH A STEADY
BACKGROUND OF LIGHT OROGRAPHIC SNOW. IF THAT BAND WOBBLES FURTHER
EAST AN ADVISORY MAY BE NEEDED. MEANWHILE ON THE PLAINS THERE IS
DRIER AIR ALOFT...BUT THE LOW LEVELS REMAIN MOIST AND THE COLD
POOL ALOFT WILL BE OVER THIS AREA...AND THERE WILL BE SOME LIFT
FROM THE TIP OF THE WARM ADVECTION NEAR THE LOW CENTER. CONVECTION
SHOULD INCREASE THROUGH THE DAY. NOT AS MUCH OF A THUNDERSTORM
RISK TODAY...CAPES LIKELY AROUND 300 J/KG AROUND DENVER AND 600
NEAR THE EASTERN BORDER. I WOULD SAY NEGLIGIBLE SEVERE THREAT
EXCEPT FOR THE COLD TEMPERATURES...COULD BE SOME HAIL OUT EAST BUT
IT SHOULD BE HARD TO GET LARGE HAIL.
FOR TONIGHT THE BACK EDGE BAND WILL TRANSLATE ACROSS OUR AREA AS
THE LOW MOVES EAST. THIS SHOULD BRING A BETTER CHANCE OF
SHOWERS. NORTH WINDS ALSO INCREASING...WHICH COULD WARM/DRY AREAS
NORTH OF DENVER BUT ENHANCE THE THREAT OF SNOW SOUTH OF DENVER.
THE NORTH WIND SHOULD ALSO BRING A FEW DEGREES OF
COOLING...LOWERING SNOW LEVELS BACK DOWN TO 5-6 THOUSAND FEET.
HOWEVER AIR TEMPERATURES WILL STILL BE ABOVE FREEZING IN MOST
AREAS...SO STILL EXPECTING LITTLE IMPACT FOR THE METRO AREA.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 512 AM MDT SAT APR 18 2015
THERE IS WEAK TO MODERATE NORTHWESTERLY JET LEVEL FLOW OVER THE
CWA SUNDAY THROUGH MONDAY NIGHT. THERE IS WEAK DOWNWARD SYNOPTIC
SCALE ENERGY FOR THE CWA SUNDAY...THEN BENIGN ENERGY SUNDAY NIGHT
THROUGH MONDAY NIGHT. THERE IS NORTHERLY FLOW IN THE LOWER LEVELS
ON SUNDAY...WITH WEAKER NORTHEASTERLIES SUNDAY NIGHT. BOUNDARY
LAYER WINDS ARE NORTHWESTERLY ON MONDAY...THEN A HINT AT NORMAL
DRAINAGE PATTERNS MONDAY NIGHT. FOR MOISTURE...THERE IS PLENTY FOR
THE CWA SUNDAY AND SUNDAY NIGHT...THE NAM BEING THE DRIEST. THERE
IS QUITE A BIT OF MOISTURE STILL AROUND BOTH MONDAY AND MONDAY
NIGHT...THE GFS BEING THE WETTEST. THERE IS A BIT OF CAPE OVER THE
FAR SOUTHWEST FORECAST AREA LATE DAY SUNDAY DAY. THERE IS A BIT
MORE CAPE OVER ALL THE HIGH COUNTRY LATE DAY MONDAY...BUT STILL
PRETTY MEAGER AMOUNTS. THE QPF FIELDS HAVE SOME MEASURABLE
PRECIPITATION MOSTLY OVER THE WESTERN TWO-THIRDS OF THE CWA
SUNDAY AFTERNOON INTO MONDAY EVENING. FOR POPS...20-50%S ARE GOOD
SUNDAY INTO MONDAY...THE LOWER NUMBERS FOR THE PLAINS. FOR
TEMPERATURES...SUNDAY`S HIGHS ARE A BIT COLDER THAN TODAY`S BEHIND
THE COLD FRONT LATE TONIGHT...EARLY SUNDAY MORNING. MONDAY`S HIGHS
ONLY WARM UP 1-2 C FROM SUNDAY`S. FOR THE LATER DAYS...TUESDAY
THROUGH FRIDAY...THERE IS AN UPPER RIDGE TUESDAY THROUGH THURSDAY
NOW ON THE MODELS. THE NEXT UPPER TROUGH LOOKS WEAKER THAN IT DID
ON YESTERDAY`S 00Z RUNS AND IT COMES THROUGH THURSDAY NIGHT AND
FRIDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1023 AM MDT SAT APR 18 2015
THE COOL...MOIST AND SLIGHTLY UNSTABLE AIRMASS WILL REMAIN OVER
NORTHEAST COLORADO THROUGH THIS AFTERNOON AND EVENING. MAY NEED TO
MENTION SOME THUNDERSTORMS AT THE DENVER AREA AIRPORTS THROUGH THE
AFTERNOON. WARMER DEW POINTS ARE MOVING INTO DENVER FROM THE
NORTHEAST SO THE THREAT OF SNOW IS GOING DOWN FOR THE REST OF THIS
AFTERNOON. STILL MAY SEE A MIX OF RAIN AND SNOW LATER TONIGHT AS
SHOWERS CONTINUE AND TEMPERATURES COOL DOWN. SHOWERS COULD BE LONG
LIVED THROUGH THE EVENING AS THE UPPER LOW PULLS OUT OF COLORADO
AND MOISTURE ON THE NORTHWEST SIDE OF THE LOW ROTATES INTO THE
DENVER AREA.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DANKERS
SHORT TERM...GIMMESTAD
LONG TERM...RJK
AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS ALBANY NY
157 PM EDT SAT APR 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION TODAY...HOWEVER ITS
ASSOCIATED MOISTURE IS RATHER LIMITED SO MAINLY ONLY AN INCREASE
IN CLOUDS IS EXPECTED. IN ITS WAKE...WINDS WILL BECOME BREEZY FOR
SEVERAL HOURS. HIGH PRESSURE WILL BUILD IN TONIGHT AND SUNDAY
RESULTING IN FAIR AND DRY WEATHER. A SERIES OF WEATHER SYSTEMS
WILL IMPACT THE REGION NEXT WEEK RESULTING IN COOL...DAMP...AND
UNSETTLED CONDITIONS. A WIDESPREAD RAINFALL IS EXPECTED MONDAY
AND MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
MORNING FOG BURNED OFF QUICKLY. A SHORT WAVE TROUGH AND ITS
ASSOCIATED LOW PRESSURE SYSTEM WILL PASS JUST TO OUR NORTHEAST
AND MOVE ACROSS NEW ENGLAND TODAY. MOISTURE REMAINS RATHER LIMITED
WITH THIS SYSTEM. LATEST HRRR ONLY INDICATES SCATTERED CONVECTION
SHOULD REMAINING MAINLY TO OUR NORTH AND EAST. THE BEST POTENTIAL
FOR SOME BRIEF SHOWER WILL BE NORTH OF ALBANY AND INTO THE
SOUTHERN GREENS OF VERMONT.
THE MAIN ISSUE FOR THE DAY IS BREEZY WESTERLY WINDS DEVELOPING
FOR THE AFTERNOON. MOMENTUM TRANSFER OF THE HIGHER MAGNITUDE
WINDS SUGGEST WE TAP INTO H700 LAYER WHERE 30+KTS RESIDES...SO
EXPECTING GUSTS OF 25 TO 35 MPH.
AS FOR TEMPERATURES...GIVEN THE DEEP MIXING EXPECTED AND CURRENT
TEMPERATURES RUNNING A COUPLE DEGREES WARMER...GUIDANCE AND DRY
ADIABATIC DECENT OF THOSE PARCELS ALONG WITH FAVORED LOCATIONS FOR
DOWNSLOPING WOULD YIELD TEMPERATURES AT 70F OR LOWER 70S FOR
VALLEY LOCATIONS AND 50S FOR THE HIGHER TERRAIN.
TONIGHT...SUBSIDENCE ALONG WITH DRIER AIR ALOFT AND SURFACE HIGH
BUILDING INTO THE REGION WILL RESULT IN DIMINISHING WINDS AND ANY
RESIDUAL CLOUD COVER. SO A CLEAR NIGHT EXPECTED WITH LOWS RANGING
FROM THE UPPER 20S ACROSS THE DACKS TO AROUND 40F ALONG THE HUDSON
RIVER FROM ALBANY AND POINT SOUTHWARD.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
GEN MODEL SUITE AGREEMENT HERE WITH SOME SPREAD TWRD THE END OF
THE PERIOD...MAINLY ON QPF AMNTS.
SUNDAY BEGINS WITH 500HPA RIDGE AXIS FM DELMARVA TO LK HURON...AND
SFC HIGH RIDGING S FM QB. RESULT WILL BE WIDESPREAD SUBSIDENCE...LOW
RH...LIGHT WINDS AND BRILLIANT SUNSHINE. SUN EVNG THE 500HPA RIDGE
WILL SLIDE OFFSHORE ALONG WITH THE SFC HIGH. OVERNIGHT EVOLVING
UPR GRT PLAINS 500HPA CUT OFF SHIFTS E...SHARPENING THE TROF/RIDGE
AMPLITUDE AND SHORTING THE WAVELENGTH AND UVM. SFC CYCLOGEN
ENSUES IN THE W OHIO VLY AND LIFTS NE INTO THE S GRTLKS MON. WMFNT
TRAILS SE FM MI-VA CAPES...AND LIFTS TWRD RGN SUN NT AS SFC LOW
ORGANIZES ON THE COAST. RESULT WILL BE RAPIDLY INCRG LLVL SFC WIND
GRAD...INCRG LLVL JETS...AND MOISTURE INFLUX INTO RGN. SHRA WILL
DEVELOP OVERNIGHT SUN AND EVOLVE INTO A WIDESPREAD RAIN INTO MON.
THE 500HPA CUT OFF OVER THE GRT PLAINS MOVES LITTLE BY TUES ONLY
REACHING LK SUPERIOR. WITH THE SFC LOW OVER ONTARIO...THE FRONTAL
STRUCTURE HAS EVOLVED INTO AN OCCLUSION FM OTTAWA VLY TO CSTL LOW
OVER S NEW ENG TUE MRNG. ONCE THE OCCLUSION CLEARS THE AREA...DRY
SLOT WRAPS ACROSS REGION WITH GENERALLY IMPVG CONDS. ALTHOUGH
THERE IS SOME SPREAD IN THE MODELS ON THE TIMING..ALL HAVE DONE SO
BY 18UTC TUES. AS 500HPA SHORT WVS ARE IN ROTATION AROUND BASE OF
CUTOFF TO OUR NW...SCT -SHRA MAY STILL OCCURRING IN STEEPENING
LAPSE RATE OVER FCA.
TEMPS WILL BE NR TO SLIGHTLY BLO NORMALS DURING THIS PERIOD WITH
HIGHS IN THE UPPER 50S TO MID 60S SUNDAY...AND MAINLY IN THE 50S
AFTERWARDS. LOWS WILL BE IN THE 30S WITH 40S TUESDAY MORNING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
THIS PERIOD WILL BE DOMINATED BY A LARGE VERTICAL LOW PRESSURE
SYSTEM CENTERED OVER ONTARIO...BUT IMPACTING MUCH OF EASTERN HALF
OF CANADA AND NE USA.
WHILE THE MODELS DIFFER IN TIMING AND PLACEMENT OF THE FEATURES...THE
MAIN STORY WILL BE 500HPA SHORT WVS ROTATING AROUND THE LARGE
CUTOFF...EACH DRAGGING A SFC FRONT/BOUNDARY THROUGH THE FCA.
THESE FEATURES WILL PRODUCE VRBL CLOUDS...AND TRIGGER SCT TO AT
TIMES BKN -SHRA... MAYBE SOME -SHSN AT HIR TRRN...HWVR THE
ACTIVITY WILL BE DIURNALLY MODULATED AS STRONG APRIL SUN...AND
STEEP LAPSE RATES WILL ENHANCE THE CONVECTIVE NATURE OF THE SYSTEM
AN MAY EVEN RESULT IN SOME SMALL HAIL.
AS ITS OFTEN WITH THESE EVENTS...WHEN FCA IS ON SE QUADRANT OF A
MAJOR CUT OFF SYSTEM...THEY TEND TO OVER DO THE DISMAL CONDITIONS
CLOUDS AND SHOWERS.
FCST PERIOD WILL FEATURE BLO NORMAL TEMPS WITH HIGHS MAINLY
50S...LOWS IN THE 30S...VRBLE CLOUDS...SCT -SHRA/-SHSN. THESE WILL
BE DRIVEN...DIURNALLY...WITH PASSING 500HPA SHORT WVS AND BY CDFNTS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A SHORT WAVE TROUGH AND ITS ASSOCIATED LOW PRESSURE SYSTEM ARE
PASSING JUST TO OUR NORTHEAST AND WILL MOVE ACROSS NEW ENGLAND
THIS AFTERNOON. SHOWERS ASSOCIATED WITH THE SYSTEM ARE GRAZING
THE EXTREME NORTHEAST PORTION OF THE FORECAST AREA AND ARE TO THE
NORTH AND EAST KGFL. SO JUST AN INCREASE IN CLOUDS IS EXPECTED
FOR THE TAFS.
WITH THE PASSAGE OF THE SYSTEM`S COLD FRONT WINDS WILL SHIFT TO
THE WEST-NORTHWEST AND INCREASE AND BECOME GUSTY WITH GUSTS
AROUND 25 KNOTS.
THE WINDS WILL WEAKEN THIS EVENING AS RIDGING BUILDS IN FROM THE
NORTHWEST AND ANY LINGER CLOUDS WILL DISSIPATE WITH LOSS OF HEATING.
WINDS WILL BECOME LIGHT OVERNIGHT AND SHIFT TO THE NORTHEAST TO
SOUTHEAST SUNDAY MORNING AS THE RIDGE BUILDS IN FARTHER.
OUTLOOK...
SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. BREEZY. LIKELY RA.
MONDAY: HIGH OPERATIONAL IMPACT. BREEZY. DEFINITE RA.
MONDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
RED FLAG WARNING FOR ALL OF EASTERN NEW YORK...BERKSHIRES AND
NORTHWEST CONNECTICUT LATER TODAY...
GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR SOUTHERN VERMONT...
EXTENSIVE COORDINATION OVERNIGHT ALONG WITH FORECAST METEOROLOGICAL
CONDITIONS HAVE WARRANTED THE UPGRADE TO RED FLAG WARNINGS FOR
EASTERN NEW YORK...BERKSHIRES AND NORTHWEST CONNECTICUT. WE WILL
HIGHLIGHT THE LOW RELATIVE HUMIDITIES...SNOW COVERAGE INTO THE
HIGHER TERRAIN...AND GUSTY WINDS WITH A SPECIAL WEATHER STATEMENT
/SPS/ FOR SOUTHERN VERMONT.
COMPACT WAVE TO THE NORTH OF THE GREAT LAKES WILL TRACK EAST-
SOUTHEAST TODAY. MOISTURE ASSOCIATED WITH THIS SYSTEM REMAINS
LIMITED...HOWEVER...ISOLATED SHOWERS ARE POSSIBLE MAINLY TO THE
NORTH OF ALBANY AND INTO SOUTHERN VT AND PERHAPS TOUCHING NORTHERN
BERKSHIRES. THEREAFTER...DEEP MIXING WITH INCREASING WINDS AND
DROPPING RELATIVE HUMIDITY VALUES YIELDS A COMBINATION OF FIRE
WEATHER HAZARDS TODAY. THE MAIN IMPACT POTENTIAL WILL BE DURING THE
AFTERNOON HOURS.
FOR SOUTHERN VERMONT...INCREASE IN CLOUD COVER ALONG WITH MARGINAL
LEVELS FOR FIRE WEATHER...SNOW COVER ACROSS THE HIGHER TERRAIN AND
COORDINATION WITH OFFICIALS HAVE RESULTED IN A SPECIAL WEATHER
STATEMENT /SPS/.
TONIGHT...WINDS WILL SUBSIDE ALONG WITH A SLOW RECOVERY OF THE
RELATIVE HUMIDITY VALUES AS A SURFACE HIGH BUILDS INTO THE REGION.
THIS HIGH REMAINS IN CONTROL THROUGH SUNDAY WITH LIGHT WINDS YET DRY
CONDITIONS WITH MINIMUM RELATIVE HUMIDITY VALUES RANGING BETWEEN 20-
30 PERCENT.
&&
.HYDROLOGY...
NO HYDROLOGY ISSUES EXPECTED THROUGH THE MONDAY MORNING AS CONDITIONS
WILL BE MAINLY DRY EXCEPT ISOLD -SHRA N TIER MIDDAY TODAY WITH A
CFP. A WIDESPREAD SOAKING RAINFALL IS LIKELY LATE SUNDAY NIGHT
INTO TUESDAY W/QPF ON THE ORDER OF HALF AN INCH TO AN INCH.
THE NATIONAL OPERATIONAL HYDROLOGIC REMOTE SENSING CENTER (NOHRSC)
INDICATES THAT THERE IS STILL A FEW INCHES OF WATER EQUIVALENT IN
THE SNOW PACK ACROSS THE SRN ADIRONDACKS AND NORTHEASTERN
BERKSHIRE COUNTY. PORTIONS OF THE SOUTHERN GREEN MOUNTAINS STILL
HAVE 4 TO 9 INCHES OF SNOW WATER EQUIVALENT.
THE GENERAL CONSENSUS IS FOR AROUND AN ONE INCH OF RAINFALL AT
THIS TIME WITH THE HIGHER TOTALS SOUTH OF THE CAPITAL DISTRICT.
THIS RAINFALL COMBINED WITH RISES FROM ONGOING SNOWMELT NORTH...MAY
RESULT IN WITHIN BANK RISES MONDAY AND TUESDAY.
FOR DETAILS ON SPECIFIC AREA RIVER AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB-
SITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013.
NY...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025.
VT...NONE.
&&
$$
SYNOPSIS...IAA/SNYDER
NEAR TERM...IAA/BGM/NAS/WASULA
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...IAA
FIRE WEATHER...IRL/WASULA
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
251 PM EDT SAT APR 18 2015
.NEAR TERM...THROUGH TONIGHT...
BUILDING UPPER RIDGE OVER FORECAST AREA THROUGH TONIGHT.
SCATTERED SHOWERS AND ISOLATED T-STORMS POSSIBLE ALONG EXISTING
BOUNDARIES...MAINLY ALONG WARM FRONT MOVING NORTHWARD OVER SRN GA
AND FL SEA BREEZES. HRRR SUGGESTS THIS WITH PEAK COVERAGE TOWARD
00Z WITH DECREASE IN COVERAGE THEREAFTER. VISIBLE SATELLITE
IMAGERY SHOWS DECENT LOW-LEVEL SW FLOW LIKELY TO PIN EAST COAST
SEA BREEZE TO COAST...THUS HRRR PRIMARILY FOCUSING ANY DEVELOPMENT
ON EASTWARD MOVING WEST-COAST SEA BREEZE. WITH LITTLE DYNAMIC
SUPPORT...WILL KEEP POP VALUES BELOW 50 THROUGH TONIGHT.
SHORT TERM...SUNDAY THROUGH MONDAY NIGHT...
UPPER RIDGING MOVES OFFSHORE WHILE STRONG UPPER TROUGH OVER THE
PLAINS SHIFTS SLOWLY EASTWARD. SURFACE LOW PRESSURE TRACKS FROM
MS NORTHEAST TO IN DURING DAY SUNDAY...WITH OUR FORECAST IN WARM
SECTOR. GREATER LOW-LEVEL SW FLOW WILL PIN EAST COAST SEA BREEZE
TO COAST WHILE ADVANCING WEST COAST SEA BREEZE EASTWARD. THIS
COMBINED WITH ACTIVITY COMING FROM NORTHEAST GULF OF MEXICO
SUPPORTS HIGH POPS...PERHAPS HIGHEST WRN/NRN AREAS...GENERALLY
50-70 PCT.
ACTIVITY DIMINISHES SUNDAY NIGHT AS MID-LEVEL DRY SLOT SPREADS OVER
FORECAST AREA. FOR MONDAY...SYSTEM CONTINUES TRACKING NORTH AND
EAST...COLD FRONT APPROACHES THE AREA FROM THE NORTHWEST. MODEL
GUIDANCE INDICATES DRIER CONDITIONS ALOFT AND BETTER DYNAMICS
PASSING WELL NORTH OF OUR FORECAST AREA...THUS CONSIDERABLY LESS
PRECIP COVERAGE MON COMPARED TO SUN. WILL MAINTAIN 30 POP MON.
DESPITE LESSER COVERAGE...MODEL GUIDNCE SUGGESTS A FEW STRONG OR
SEVERE STORMS WILL BE POSSIBLE IN AN ENVIRONMENT WITH 2000 J/KG
CAPE AND 150-200 0-3KM SR-HELICITY. SPC HAS A MARGINAL/SLIGHT RISK
AREA OVER MOST OF OUR AREA MON.
WARM SUN AND MON WITH HIGHS 80 TO 85 NORTH OF I-10 CORRIDOR...MID
80S I-10 SOUTHWARD.
FRONT AND ASSOCIATED PRECIP SHIFT OFFSHORE MON NIGHT. FRONT
WASHES OUT OVER THE SOUTHERN PART OF FORECAST AREA WHILE WEAK
HIGH PRESSURE APPROACHES FROM THE GULF COAST STATES.
LONG TERM...TUESDAY THROUGH SATURDAY...
DRIER CONDITIONS WITH HIGH PRESSURE BUILDING NORTH OF THE AREA TUE.
SLIGHTLY COOLER HIGH TEMPS IN UPPER 70S TO LOWER 80S. WILL
CONTINUE TO CONFINE LOW POPS TO OUR SOUTHERN COUNTIES.
LITTLE CHANGE WED-FRI...WITH ISOLATED SEA BREEZE SHOWERS POSSIBLE
FL PENINSULA. BETTER CHANCE OF RAIN MAY COME NEXT SAT...BASED ON
GFS AND ECM...AND WILL SHOW POPS INCREASING THEN. HIGH TEMPS
GRADUALLY INCREASING TO MID 80S BY END OF WEEK.
&&
.AVIATION...GENERALLY VFR CONDITIONS EXPECTED NEXT 24 HRS...EXCEPT
LOCALLY LOWERER IN ISOLATED TSRA AND AREAS WHERE LATE NIGHT
PATCHY FOG OCCURS.
&&
.MARINE...SOUTH TO SOUTHWEST WINDS 10-15KTS AND 2-4FT SEAS EXPECTED
THRU MONDAY AHEAD OF NEXT COLD FRONT. AFTER FRONT PASSES...WINDS
WILL BECOME NORTH AND THEN NORTHEAST WITH HIGH PRESSURE BUILDING
JUST NORTH OF THE AREA. THE HIGH IS EXPECTED TO BE WEAK...RESULTING
IN FAIRLY WEAK WINDS AND LOW SEAS TUE/WED. BEFORE THE FRONT PASSES
MON NIGHT...WINDS COULD APPROACH SMALL CRAFT ADVISORY LEVELS
ACROSS THE OFFSHORE COMPONENT.
.RIP CURRENTS...MODERATE RISK THROUGH SUNDAY DUE TO A LINGERING SWELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 67 82 67 83 / 40 80 20 30
SSI 68 80 69 82 / 30 60 40 30
JAX 69 85 69 85 / 30 60 30 30
SGJ 69 82 69 83 / 30 50 30 30
GNV 68 85 68 85 / 20 60 20 30
OCF 68 85 69 85 / 20 50 20 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
WOLF/SANDRIK/GUILLET
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1249 PM CDT Sat Apr 18 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 342 AM CDT SAT APR 18 2015
Showers and thunderstorms developing this hour across northeast
Oklahoma into south central and north central Kansas, with cell
movement toward the north northwest and the cluster moving more
northerly. This area is forecast to move across the forecast area
through the morning hours today.
Struggle with the forecast continues to be timing and coverage of
precipitation chances. After initial energy lifts across Eastern
Kansas through early afternoon, next uncertainty will be for chances
later in the afternoon. HRRR develops a cluster of showers in south
central KS, but would anticipate a break between the systems with
subsidence behind the main wave inhibiting convective development.
Have higher chances in the morning, with lower chances middle
afternoon, followed by an increase from west to east through the
evening into the overnight hours as the main wave finally starts to
get an easterly push, from both a northern US shortwave and an upper
jet traversing the southern states. With a lull in precipitation
and possibly some better sunshine out west, this would boost
instability and chances for severe thunderstorms as late day storms
develop along the dryline to our west and along the northward
advancing warm front. Primary threat would be hail, but closer
proximity to these surface features in north central Kansas could
bring an isolated tornado risk there. General precipitation chances
continue in the overnight hours ahead of the upper low as it
continues to slowly move east. Highs for Saturday in the middle 70s
west to near 70 east, with lows in the 50s.
.LONG TERM...(Sunday through Friday)
Issued at 342 AM CDT SAT APR 18 2015
By Sunday morning the mid/upper low will be centered over SC KS and
NC OK as it progresses eastward. During this time the low will
become more of an open wave as another shortwave digs into the
northern plains and upper Midwest. These waves will bring a cold
front through the region during the day Sunday. In the morning the
better chance for showers and some thunder should be in southern KS
where the front and mid level low are more coupled in the vertical.
By 18Z the models are hinting at an increase of instability on the
order of about 1000 j/kg ahead of the front that should stretch
across eastern KS. Lapse rates are not overly impressive, and deep
layer shear could reach 30 kts. Although the better shear will be
further southeast over southern MO where the flow aloft is slightly
stronger. Therefore kept a mention of thunderstorms for east central
KS during the afternoon. A majority of the precip should clear the
area around 03Z in the evening.
A sharp pressure gradient behind the front will support northwest
surface winds around 15 to 25 mph with gusts as up to 35 mph
especially in NC KS. Cold air advection on the backside of the wave
drops temps into the lower 40s and upper 30s by Monday morning.
Winds do not completely decouple Sunday night so there is little
concern for frost. On Monday winds remain gusty with high temps
generally around 60 and partly sunny skies. Monday night will not be
the classic set up for frost with a expansive high building
southward, but the winds do decrease and temps are forecast to reach
the mid to upper 30s. Therefore could not rule out the possibility
for frost perhaps in preferred sheltered locations.
NW flow aloft develops over the region as the northern stream wave
deepens over the Great Lakes. The models are beginning to advertise
embedded shortwaves within the NW flow, which track over the plains
around mid week. This will bring small chances for either showers or
thunderstorms. Late in the week a southern wave crashes the southern
CA coast and tracks northeastward towards the center of the country.
There are some differences on how far north the instability reaches
ahead of the system, and there are additional waves in the NW flow
that could interfere with the southern stream system. Confidence in
any solution is low at this point.
&&
.AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon)
Issued at 1249 PM CDT SAT APR 18 2015
VFR conditions are expected outside of convective activity. MVFR
to areas of IFR are expected near MHK through 20Z then an
improvement to VFR by 21Z. SHRA will continue through 21Z at TOP
and FOE with MHK having a low probability of shra through 00Z.
High resolution short range models develop tsra in western and
central KS then move it northeast toward MHK by 06Z, then
affecting TOP and FOE after 09Z. WInds shift to the northwest in
the 14Z-16Z period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Sanders
AVIATION...53
AREA FORECAST DISCUSSION
NWS WICHITA KS
1242 PM CDT SAT APR 18 2015
...UPDATED FOR 18Z AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 350 AM CDT SAT APR 18 2015
THE UPPER LOW HAS SHIFTED EASTWARD AND IS SPINNING OVER COLORADO.
SMALL PIECES OF ENERGY WITH IT HAVE HELPED TO SPARK OFF SHOWERS
AND THUNDERSTORMS OVER THE PLAINS STATES DURING THE OVERNIGHT
HOURS. EXPECT CENTRAL AND EASTERN KANSAS TO SEE SHOWERS AND
THUNDERSTORMS THROUGH MUCH OF THE MORNING.
BILLINGS WRIGHT
&&
.UPDATE...
ISSUED AT 1037 AM CDT SAT APR 18 2015
MAIN UPPER LEVEL LOW OVER THE CO ROCKIES IS BEGINNING TO MAKE SLOW
PROGRESS INTO THE PLAINS THIS MORNING. DIFFLUENT SW FLOW AHEAD OF
THIS UPPER LOW HAS LED TO ANOTHER ROUND OF SHOWERS AND EMBEDDED
STORMS OVER THE ERN HALF OF KS. EXPECT THE SHOWERS IN ERN KS TO
GRADUALLY SHIFT TO THE E-NE OF THE AREA LATE THIS MORNING. BUT
ATTENTION QUICKLY SHIFTS BACK TO THE WEST...AS THIS UPPER LOW BEGINS
TO PUSH EAST INTO WRN KS. ALREADY SEEING SOME CLEARING ACROSS THE
WESTERN HALF OF THE FORECAST AREA...WHICH WILL LEAD TO INCREASED
SURFACE HEATING INTO THE AFTERNOON HOURS. SETUP IS A LITTLE
DIFFERENT THAN YESTERDAY...AS DRYLINE IN SW KS IS ON THE MOVE TO THE
EAST THIS MORNING...CURRENTLY JUST TO THE WEST OF THE KDDC.
LATEST LOOK AT THE HI-RES SHORT TERM MODELS SUGGEST THAT THE
INCREASED HEATING BETWEEN THE DRYLINE AND WRN SECTIONS OF THE
FORECAST AREA WILL HELP DESTABILIZE THE ATMOSPHERE JUST TO THE WEST
OF THE FORECAST AREA THIS AFTERNOON. THIS AREA IS ALSO WEAKLY
CAPPED. SO BETTER HEATING THIS MORNING...AND NOT ALOT OF RECOVERY
TIME NEEDED...MAY LEAD TO CONVECTION DEVELOPING EARLIER THAN
YESTERDAY. ESPECIALLY JUST AHEAD OF THE DRYLINE AS IT PUSHES EAST OF
KDDC...AND PUSHES TO JUST WEST OF KPPT. SO MAY SEE CONVECTION
DEVELOP AND MOVE INTO WRN SECTIONS OF THE FORECAST AREA (WEST OF I-
135) BETWEEN 20-22Z. LATEST HRRR AND ARW SUGGEST THIS SCENARIO.
AS FAR AS SEVERE WEATHER CHANCES...BULK SHEAR AROUND 40 KTS AND
SBCAPE VALUES EXPECTED TO BE IN THE 2000-2500 J/KG SUGGEST A STRONG
TO SEVERE CHANCE WITH A MIXED MODE WITH MULTICELL CLUSTERS AND A FEW
LOW TOPPED SUPERCELLS WITH LARGE HAIL (QUARTER TO GOLFBALL) AND
DAMAGING WINDS THE MAIN CONCERN. CANNOT RULE OUT A WEAK/BRIEF
TORNADO OR TWO...GIVEN THE DIRECTIONAL SHEAR AND INCREASED VERTICAL
STRETCHING DUE TO THE STEEP LAPSE RATES.
KETCHAM
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 350 AM CDT SAT APR 18 2015
MORNING:
EXPECT THE SHOWERS AND THUNDERSTORMS CURRENTLY ONGOING TO CONTINUE
TO DEVELOP AND SHIFT EAST-NORTHEASTWARD DURING THE MORNING HOURS.
DO NOT EXPECT THESE TO BE STRONG OR SEVERE...JUST A WELCOME DRINK
OF RAIN.
THIS AFTERNOON/EVENING:
THINK THAT THERE MAY BE SOME CLEARING ACROSS WESTERN AREAS THIS
MORNING/EARLY AFTERNOON BEFORE THUNDERSTORMS FIRE AGAIN THIS
AFTERNOON ALONG AND AHEAD OF THE DRYLINE. STILL SLIGHTLY CONCERNED
THAT STORMS COULD FIRE EARLIER IN THE AFTERNOON...CLOSER TO 18Z
WITH THE SUPPORT FROM THE UPPER DYNAMICS OF THE UPPER
LOW...HOWEVER...THE BEST SUPPORT FOR COVERAGE IS CLOSER TO 21Z TO
00Z. EXPECT THESE STORMS TO IMPACT CENTRAL AND SOUTH CENTRAL
KANSAS WHERE INSTABILITY AND SHEAR PARAMETERS ARE PLENTIFUL TO
SUPPORT SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WIND. THERE
IS STILL A SMALL CHANCE FOR A TORNADO...BEST CHANCES RESIDE IN
SOUTH CENTRAL KANSAS AND CLOSER TO THE OKLAHOMA BORDER WITH THE
BETTER HELICITY/EHI FURTHER SOUTH IN OKLAHOMA. EXPECT STORMS TO
MOVE EASTWARD DURING THE EVENING. THE SEVERE CHANCES DECREASE
OVER SOUTHEAST KANSAS THOUGH AS THE PARAMETERS ARE LESS FAVORABLE
THERE TO SUPPORT SEVERE STORMS.
DURING THE OVERNIGHT HOURS SATURDAY INTO SUNDAY:
THE UPPER LOW WILL CONTINUE TO PUSH EASTWARD AND LOBES OF
VORTICITY ARE EXPECTED TO CIRCLE AROUND IT WHICH COULD SPARK
MULTIPLE ROUNDS OF SHOWERS/THUNDERSTORMS OVER SOUTHERN KANSAS. THE
UPPER LOW WILL TRAVERSE THE STATE SUNDAY...THUNDERSTORMS WILL
BECOME SHOWERS AND THE FOCUS WILL SHIFT TO EAST AND SOUTHEAST
KANSAS. A COLD FRONT ASSOCIATED WITH THE UPPER LOW WILL MOVE
ACROSS THE STATE AND SHIFT WINDS TO THE NORTHWEST AND GUSTY.
TEMPERATURES WILL BE COOLER ON MONDAY...IN THE 60S BUT THINGS
SHOULD BE DRY AS THE UPPER LOW SLOWLY BEGINS TO SHIFT
NORTHEASTWARD.
BILLINGS WRIGHT
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT APR 18 2015
THE MAIN UPPER LOW IS SLOW TO EXIT AND A PIECE OF ENERGY ROTATING
AROUND ITS BACK SIDE IT WILL IMPACT THE AREA WHILE THE CENTRAL
PLAINS SITS UNDER NORTHWESTERLY UPPER LEVEL FLOW. PRECIPITATION
CHANCES WILL BE POSSIBLE EARLY TUESDAY AND THROUGHOUT THE
DAY...BUT THE GUIDANCE HAS DISCREPANCIES AMONGST THE LOCATION OF
THE PRECIPITATION...THINK IT COULD BE SOUTH OF THE STATE
LINE...HOWEVER THE GFS PUSHES IT RIGHT OVER CENTRAL KANSAS.
CONFIDENCE ON THIS PERIOD AND PRECIPITATION CHANCES IS LOW.
BY WEDNESDAY THROUGH FRIDAY THE UPPER LOW MOVES OFF TO THE
NORTHEAST AND ANOTHER SYSTEM MOVES IN FROM THE SOUTHWEST.
PRECIPITATION AND POSSIBLY THUNDERSTORM CHANCES INCREASE BY
WEDNESDAY THROUGH FRIDAY ACROSS THE AREA. THIS PERIOD HAS QUITE A
FEW DISCREPANCIES WITH THE VARIOUS SOLUTIONS...CONFIDENCE ON ANY
SOLUTION IS LOW.
TEMPERATURES WILL STAY IN THE UPPER 60S AND LOW 70S...NEAR
SEASONAL NORMALS.
BILLINGS WRIGHT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1240 PM CDT SAT APR 18 2015
A RATHER DIFFICULT AVIATION FORECAST...AS AN UPPER LEVEL SYSTEM
CURRENTLY OVER ERN CO WILL LEAD TO LOTS OF LOW LEVEL MOISTURE ACROSS
MOST OF THE FORECAST AREA. AS LIFT FROM THIS LOW INCREASES...EXPECT
SHRA/TSRA TO DEVELOP IN THIS UNSTABLE ATMOSPHERE ACROSS MOST OF THE
FORECAST AREA AFTER 22Z/SAT. SO PLAN ON GOING WITH VCTS FOR MOST
LOCATIONS FOR THIS CHANCE. ALSO WILL GO WITH A TEMPO GROUP FOR MVFR
VSBYS IN AND AROUND THE STRONGER STORMS NEAR THE KICT/KHUT AND KRSL
TAF SITES.
EXPECT THE THUNDER CHANCES TO CONTINUE WELL INTO THE EVENING
HOURS...ESPECIALLY FOR AREAS NEAR THE KICT/KHUT/KSLN AND KRSL TAF
SITES.
KCNU WILL SEE A LATER ARRIVAL FOR THE VCTS....TO AROUND 06Z. THE
DEEPER LOW LEVEL MOISTURE COULD LEAD TO SOME MVFR CIGS AS WELL.
EXPECT A GRADUAL WIND SHIFT TO THE WEST FOR THE KRSL TAF BY SUN
MORNING.
KETCHAM
&&
.FIRE WEATHER...
ISSUED AT 350 AM CDT SAT APR 18 2015
FIRE WEATHER CONCERNS REMAIN LOW WITH THE UPPER LEVEL SYSTEM
IMPACTING THE AREA CAUSING MULTIPLE ROUNDS OF PRECIPITATION.
THE GRASSLAND FIRE DANGER INDEX REMAINS BELOW ELEVATED CONCERN
LEVELS.
BILLINGS WRIGHT
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 75 54 66 39 / 50 60 70 10
HUTCHINSON 75 52 62 39 / 50 60 70 10
NEWTON 73 52 62 40 / 50 60 80 10
ELDORADO 74 54 69 41 / 40 60 80 10
WINFIELD-KWLD 74 54 70 40 / 40 60 70 10
RUSSELL 75 51 59 36 / 50 60 60 10
GREAT BEND 74 50 59 35 / 50 60 60 10
SALINA 76 52 61 38 / 50 60 70 10
MCPHERSON 74 52 60 38 / 50 60 70 10
COFFEYVILLE 73 56 70 43 / 80 60 80 20
CHANUTE 72 56 70 42 / 80 60 80 20
IOLA 71 56 69 42 / 80 60 80 20
PARSONS-KPPF 73 56 69 42 / 80 60 80 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
421 PM CDT SAT APR 18 2015
.SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS SLOW-MOVING UPR LOW OVER
ERN COLORADO...WITH MOIST SWLY FLOW CONTINUING TO STREAM OVER THE
REGION. ONE IMPULSE ASSOCIATED WITH THIS SYSTEM WAS MOVING ACRS
SRN TX INTO THE WRN GULF...WITH A SECOND IMPULSE CROSSING WRN TX.
THESE TWO SYSTEMS WERE TRIGGERING STORMS ACRS THE NW/CNTL GULF
COAST AS WELL AS ACRS WRN TX. OVER THE IMMEDIATE CWA...ACTIVITY
HAS REMAINED FAIRLY SCTD...WITH A SWATH OF LT/MODT RAIN OVER THE
COASTAL WATERS...AND SCT SHRA/TSRA ACRS CNTL/WRN LA.
&&
.DISCUSSION...
OVERNIGHT CONVECTIVE COMPLEX ALLOWED THE AIRMASS TO STABILIZE
TODAY...AND ONGOING CONVECTION OVER THE GULF HAS LIMITED INFLOW.
THIS COMBINATION HAS REDUCED THE POTENTIAL FOR HEAVY RAIN AND
WIDESPREAD ACTIVITY TODAY AND LIKELY INTO TONIGHT. LOOKING AT A
COMBINATION OF RECENT HRRR RUNS AS WELL AS RAP/NAM GUIDANCE SHOWS
A DECREASING TREND DURING THE EVENING AND OVERNIGHT. ACTIVITY
ALONG THE TX COAST IS EXPECTED TO TREK E/NE BUT GRADUALLY WEAKEN
AS IT APPROACHES OUR COASTAL WATERS ZONES. LIKEWISE...THE STORMS
ACRS WRN TX WILL MOVE EAST THIS EVENING...BUT ALSO WEAKEN AS THEY
REACH THE AREA LATER TONIGHT. QPF VALUES ARE EXPECTED TO REMAIN
BELOW AN INCH THROUGH SUNDAY...AND WITH THIS IN MIND...HAVE GONE
AHEAD AND CANCELLED THE FLASH FLOOD WATCH.
DRIER MID LVL AIR WILL BEGIN TO PUSH EAST OVER THE AREA ON
SUNDAY...HELPING TO BRING A REPREIVE FROM THE RAINY PATTERN.
HOWEVER...ENOUGH MOISTURE WILL LINGER TO ALLOW FOR AT LEAST A SLT
CHC FOR A FEW SHOWERS OR TSTMS. BY SUNDAY NIGHT...A COOL FRONT
WILL MOVE THROUGH THE REGION. ENOUGH CONVERGENCE AND LIFT ARE
EXPECTED ALONG THE FRONTAL BOUNDARY TO PRODUCE A SCT BAND OF
SHOWERS AND TSTMS AS IT CROSSES THE AREA. SPC DOES HAVE THE AREA
OUTLINED IN A SLT RISK FOR SUNDAY/SUNDAY NIGHT AS INSTABILITY
LOOKS TO INCREASE AHEAD OF THE BOUNDARY. THUS AN ISOLATED STRONG
TO SEVERE STORM CANNOT BE RULED OUT ESPECIALLY ACRS THE NRN TIER
OF COUNTIES AND PARISHES.
DRY WEATHER FINALLY RETURNS ON MONDAY AND SHOULD CONTINUE INTO
TUESDAY AS HIGH PRES BUILDS INTO THE AREA. SMALL RAIN CHCS WILL
RETURN BY MIDWEEK WITH CHCS INCREASING TOWARD THE LATTER PART OF
THE WEEK. ZONAL FLOW WILL PREVAIL THROUGH THE WEEK AND LIFT
ASSOCIATED WITH EMBEDDED DISTURBANCES WILL KEEP AT LEAST CHC POPS
OVER THE AREA THURSDAY AND FRIDAY.
&&
.MARINE...
LT TO MDT SWLY FLOW WILL CONTINUE THROUGH SUNDAY WITH SHOWERS AND
TSTMS GRADUALLY DIMINISHING. A COOL FRONT WILL CROSS THE COASTAL
WATERS LATE SUNDAY NIGHT...WITH MODT OFFSHORE FLOW DEVELOPING
FOR MONDAY. EXERCISE CAUTION CONDITIONS COULD BE POSSIBLE AT TIMES
MONDAY INTO TUESDAY. WINDS WILL GRADUALLY VEER ELY TUESDAY...THEN
SELY BY WEDNESDAY AS SFC HIGH PRES MOVES EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 63 83 60 76 / 40 20 30 10
LCH 64 82 63 79 / 30 10 20 10
LFT 65 84 64 79 / 50 20 20 10
BPT 64 82 63 79 / 30 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE...24
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
308 PM CDT SAT APR 18 2015
.AVIATION...
TERMINALS WILL CONTINUE TO PREVAIL WITH MVFR AND IFR FLIGHT
CATEGORIES WITH WIDELY SCATTERED SHOWERS. THERE HAVE BEEN VERY FEW
THUNDERSTORMS SO THOSE WILL BE OMITTED FROM THE FORECAST AND
ADDED AS THEY INCREASE IN AREAL COVERAGE AND LOOK TO AFFECT
FORECAST SITES WILL AMEND AS NEEDED. A SURFACE LOW OVER LOWER
PARTS OF EAST TEXAS WILL LIFT TO THE NORTHEAST MOVING A WARM FRONT
NORTHEAST OVER THE EASTERN SECTIONS OF THE FOUR STATE REGION.
WINDS WILL BE VARIABLE WITH SOUTHEAST TO SOUTHWEST OVER THE
SOUTHEAST SIDE OF THE LOW PRESSURE AREA AND NORTHEAST TO NORTHERLY
AROUND THE BACK SIDE AS IT LIFTS NORTHEAST. A SERIES OF UPPER
LEVEL DISTURBANCES ROUNDING THE LARGE AND BROAD BASE OF AN UPPER
TROUGH OF LOW PRESSURE TO OUR WEST WILL CONTINUE TO PROVIDE
PERIODS OF SHOWERS DURING THE NIGHT AND ON SUNDAY AS THEY ASSIST
THE SURFACE LOW AND ITS MOVEMENT. THUNDERSTORMS WILL BE ON THE
INCREASE DURING THE AFTERNOON SUNDAY AND INTO THE EVENING. /06/
&&
.PREV DISCUSSION... /ISSUED 1118 AM CDT SAT APR 18 2015/
DISCUSSION...
MOST OF THE MODELS ARE NOT HANDLING THE ONGOING PRECIP VERY WELL
DEPICTING WAY TOO MUCH COVERAGE COMPARED TO WHAT IS ACTUALLY
OCCURRING. LACK OF PRECIP BACK TO THE SW ALSO LENDS LOW CONFIDENCETO
THE MODELS. HRRR SEEMS TO BE PERFORMING SLIGHTLY BETTER SO HAVE
TRIMMED POPS SLIGHTLY BASED ON THE MORE SCATTERED COVERAGE
EXPECTED BY THE HRRR ACROSS MAINLY THE NERN HALF OF THE CWA
THROUGH THE REMAINDER OF TODAY. STARTING TO SEE A FEW BREAKS IN
THE CLOUDS WHICH WILL HELP TEMPS TO WARM QUICKLY. INSTABILITY WILL
BE SUFFICIENT TO SUPPORT AT LEAST AN ISOLATED SEVERE THREAT IN
PLACE.
OTHERWISE...ONLY A FEW MINOR CHANGES WERE MADE TO DEWPOINT AND
WIND GRIDS BASED ON LATEST OBS. UPDATED PRODUCTS HAVE BEEN SENT.
/09/
PREV DISCUSSION... /ISSUED 652 AM CDT SAT APR 18 2015/
PREV DISCUSSION... /ISSUED 538 AM CDT SAT APR 18 2015/
DISCUSSION...
MOSTLY CLOUDY WITH MID TO UPPER 60S AND VARIABLE WINDS OVER THE
FOUR STATE AREA. THE KSHV 88D RADAR IS SHOWING MOST COVERAGE OF
SHOWER AND ISOLATED THUNDERSTORMS OVER OUR OKLAHOMA AND TEXAS
COUNTIES WITH DEPARTING COVERAGE FOR NOW OVER NORTH CENTRAL
LOUISIANA AND SOME OF THE TEXAS SOUTHERN FLANK PULLING ACROSS
TOLEDO BEND. OVERNIGHT...WE WERE CUT OFF FROM DECENT GULF
MOISTURE BY A LARGE THUNDERSTORM COMPLEX MOVING EAST ALONG I-10.
LOOKING AT THE WATER VAPOR...THE THICK BELT OF PACIFIC MOISTURE
IS STILL BACK ACROSS SOUTH TEXAS...AND LIFTING THIS WAY.
MEANWHILE...THE UPPER LOW IS SLOWLY EDGING OFF THE FOUR CORNERS
INTO CO/NB/KN NOW THANKS TO ANOTHER DEEPENING TROUGH ON THE NW
COAST. THE COLD FRONT WILL NOT ARRIVE UNTIL LATE AFTERNOON SUNDAY
AND INTO THE EVENING. SO TODAY LOOKS MORE FAVORABLE FOR WIDE
SPREAD COVERAGE WITH ONLY A MARGINAL RISK FOR SEVERE AND THEN ON
SUNDAY WE ARE SLIGHT/ENHANCED FOR SEVERE WITH THE COLD FRONT BY
MORE LIMITED WIDE SPREAD COVERAGE. OUR DEW POINTS WILL BE LOW TO
MID 60S WITH SOME MORE HEATING AHEAD OF THE FRONT ARRIVING WITH
SOME LIFT WHILE STILL UNDER THE UPPER DIVERGENT TROUGH TO OUR
WEST. SPC IS LOOKING FOR ANOTHER MCS BY LATE SUNDAY AFTERNOON AND
MOVING EAST QUICKLY INTO THE EVENING WHILE THE MODELS ARE ALL OVER
THE PLACE WITH QPF. LITTLE CHANGE WITH A COOL DOWN BACK TO NORMAL
FOR THE NEW WORK WEEK AND THEN ANOTHER FRONT MID TO LATE WEEK.
/24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 62 83 56 74 / 50 20 20 10
MLU 63 81 58 75 / 60 40 30 10
DEQ 58 79 50 72 / 40 30 10 10
TXK 59 80 53 72 / 40 30 20 10
ELD 60 81 54 73 / 50 40 30 10
TYR 61 82 53 73 / 40 20 10 0
GGG 61 82 54 73 / 40 20 10 0
LFK 64 85 57 76 / 50 20 20 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
06
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
220 PM CDT SAT APR 18 2015
.AVIATION...
CLOUDS AND RAINS TO CONTINUE INTO THE EVENING HOURS. CEILINGS TO
VARY FROM MVFR TO IFR ALSO VSBY EXPECTED TO REMAIN ABOVE 3 SM.
&&
.PREV DISCUSSION... /ISSUED 1159 AM CDT SAT APR 18 2015/
UPDATE...
OVERNIGHT CONVECTIVE COMPLEX HAS MOVED EAST OF THE
REGION...ALLOWING THE AIRMASS TO STABILIZE BRIEFLY. ADDITIONAL
CONVECTION IS BEGINNING TO DEVELOP ACRS SRN TX IN ASSOCIATION
WITH THE NEXT IMPULSE IN THE MOIST SWLY FLOW. EXPECT SCT TO NMRS
SHRA/TSRA TO DEVELOP DURING THE AFTN AS THIS IMPULSE TRAVELS OVER
THE AREA. ADJUSTED POPS TODAY TO REFLECT RECENT HRRR AND RAP RUNS.
ALSO ADJUSTED QPF AMOUNTS...AND THIS PRODUCED MUCH LOWER QPF ACRS
SE TX. THUS...CANCELLED THE FFA ACRS OUR SE TX ZONES. KEPT FFA UP
ACRS LA AND ALTHOUGH THE RISK OF WIDESPREAD HEAVY RAIN AND
FLOODING IS LOWER...THERE IS STILL THE POSSIBILITY FOR SOME
LOCALIZED HEAVY RAIN ACRS PORTIONS OF SW LA. REMAINDER OF FCST IS
RELATIVELY UNCHANGED WITH JUST SOME MINOR EDITS TO HOURLY
TEMPS...DEWPOINTS AND WINDS. 24
PREV DISCUSSION... /ISSUED 656 AM CDT SAT APR 18 2015/
AVIATION...AEX STARTING OUT IFR ON CIGS THIS MORNING. ELSEWHERE
VFR CIGS WITH LGT RAIN. THERE COULD BE A FEW EMBEDDED TSTMS LATER
THIS MORNING. MVFR LATE TNITE AS WE SCATTER OUT ALOFT BUT REMAIN
MOIST IN THE BOUNDARY LAYER. COULD SEE SOME IFR CIGS IN SCUD ALONG
WITH SOME LIGHT FOG.
SWEENEY
PREV DISCUSSION... /ISSUED 501 AM CDT SAT APR 18 2015/
DISCUSSION...
HEAVY RAINS OVERNIGHT SO FAR HAVE BEEN CONFINED MAINLY TO
SOUTHERN JEFFERSON COUNTY IN SOUTHEAST TEXAS WITH 3-4 INCHES OF
RAIN MAINLY SOUTH OF URBAN AREAS...TO 2 TO 3 INCHES IN NORTHWEST
CAMERON PARISH OVER THE MARSHES. OTHERWISE...1 TO 2 INCH RAINS
WERE COMMON FROM OPELOUSAS...WEST TO DEQUINCY...TO ORANGE AND
VILLAGE MILLS. THE NORTHERN AREAS HAVE BEEN SPARED THIS TIME
AROUND.
THE BIG QUESTION TODAY IS THE AMOUNT OF AVAILABLE MOISTURE AND
INSTABILITY NEEDED TO CONTINUE THE FLASH FLOOD WATCH AND OF
COURSE THE RISK OF SEVERE STORM DEVELOPMENT. THE ATMOSPHERE HAS
BEEN WORKED OVER PRETTY WELL...AND THE CONVECTION OVER THE COASTAL
WATERS FROM 40NM TO WELL BEYOND 60NM HAS DIVERTED THE DEEP GULF
MOISTURE FURTHER SOUTH WAY FROM AREA. THERE IS A GOOD PLUME OF
CLOUDS BLOWING OFF GULF CONVECTION SWEEPING NORTHWARD ACROSS AREA
TODAY. ON THE OTHER HAND...SOUNDING FORECAST PROFILES SHOW
PRECIPITABLE WATER VALUES HOLDING ABOVE 1.5 INCHES OR BETTER AT
LEAST UNTIL 00Z AND THEN DROP OFF. THEREFORE...WILL NOT MENTION
SEVERE THUNDERSTORMS IN THE FORECAST AS THE RISK FROM SPC IS
SLIGHT. CLOUDS MAY HINDER INSTABILITY FOR MOST OF THE DAY ANYWAY.
HOWEVER...CANNOT RULE OUT AN ISOLATED BRIEF SEVERE MID TO LATE
AFTERNOON SOMEWHERE...BUT THAT WOULD BE ISOLATED IF ANY.
THE FLASH FLOOD WATCH COULD BE LIFTED TODAY IF IT WERE NOT FOR
THE SATURATED SOILS AND FILLED DITCHES. REALLY BELIEVE THAT THE
FIRST HALF OF THE MORNING THERE IS LITTLE OF ANY THREAT OF HEAVY
RAINS...HOWEVER IN THE AFTERNOON...COULD SEE SOME REDEVELOPMENT OF
HEAVIER RAINS FROM UPSTREAM INSTABILITY...THEREFORE...WILL LEAVE
FLASH FLOOD WATCH UP FOR NOW AS IT WOULD NOT BE PRUDENT TO MOVE IT
JUST YET.
THE UPPER LEVEL LOW SPINNING ACROSS COLORADO THIS MORNING WITH THE
SOUTHERLY TROUGH EXTENDING INTO THE SOUTH CENTRAL SOUTHERN
STATES...WILL CONTINUE TO MIGRATE EASTWARD OVER THE NEXT 48 HOURS.
AS IT DOES...DEEP MOISTURE AND ENERGY WILL SHIFT EASTWARD DURING
THIS PERIOD. THEREFORE...DO EXPECT TO SEE A BIG DROPOFF IN RAIN
CHANCES ON SUNDAY BUT KEEP LOW POPS IN AS AS FRONT SWEEPS THROUGH
THE AREA LATE SUNDAY NIGHT INTO MONDAY. THE FRONT WILL RETURN AS A
WARM FRONT BY MIDWEEK AND THEREFORE WILL GET A BUMP UP IN POPS AS
THE WARM FRONTAL BOUNDARY MOVES NORTHWARD. RAIN CHANCES ONCE AGAIN
FALL BY THE END OF THE WEEK AS THE REGION WILL REMAIN BETWEEN
SYSTEMS.
MARINE...
AM WIDESPREAD CONVECTION WILL END FROM WEST TO EAST THIS MORNING.
REDEVELOPMENT COULD BEGIN LATER THIS AFTERNOON BUT PROBABLY WILL
NOT BE QUITE AS BAD AS THE LAST COUPLE OF DAYS HAVE BEEN. ONSHORE
FLOW WILL CONTINUE WITH PERIODIC DISRUPTION DUE TO THUNDERSTORMS
AND OUTFLOWS.
06
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 64 82 61 78 / 50 20 20 10
LCH 65 82 64 80 / 40 20 20 10
LFT 66 84 65 80 / 60 30 20 10
BPT 65 82 64 80 / 40 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>033-
041>045-052>055-073-074.
TX...NONE.
GM...NONE.
&&
$$
AVIATION...19
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1159 AM CDT SAT APR 18 2015
.UPDATE...
OVERNIGHT CONVECTIVE COMPLEX HAS MOVED EAST OF THE
REGION...ALLOWING THE AIRMASS TO STABILIZE BRIEFLY. ADDITIONAL
CONVECTION IS BEGINNING TO DEVELOP ACRS SRN TX IN ASSOCIATION
WITH THE NEXT IMPULSE IN THE MOIST SWLY FLOW. EXPECT SCT TO NMRS
SHRA/TSRA TO DEVELOP DURING THE AFTN AS THIS IMPULSE TRAVELS OVER
THE AREA. ADJUSTED POPS TODAY TO REFLECT RECENT HRRR AND RAP RUNS.
ALSO ADJUSTED QPF AMOUNTS...AND THIS PRODUCED MUCH LOWER QPF ACRS
SE TX. THUS...CANCELLED THE FFA ACRS OUR SE TX ZONES. KEPT FFA UP
ACRS LA AND ALTHOUGH THE RISK OF WIDESPREAD HEAVY RAIN AND
FLOODING IS LOWER...THERE IS STILL THE POSSIBILITY FOR SOME
LOCALIZED HEAVY RAIN ACRS PORTIONS OF SW LA. REMAINDER OF FCST IS
RELATIVELY UNCHANGED WITH JUST SOME MINOR EDITS TO HOURLY
TEMPS...DEWPOINTS AND WINDS. 24
&&
.PREV DISCUSSION... /ISSUED 656 AM CDT SAT APR 18 2015/
AVIATION...AEX STARTING OUT IFR ON CIGS THIS MORNING. ELSEWHERE
VFR CIGS WITH LGT RAIN. THERE COULD BE A FEW EMBEDDED TSTMS LATER
THIS MORNING. MVFR LATE TNITE AS WE SCATTER OUT ALOFT BUT REMAIN
MOIST IN THE BOUNDARY LAYER. COULD SEE SOME IFR CIGS IN SCUD ALONG
WITH SOME LIGHT FOG.
SWEENEY
PREV DISCUSSION... /ISSUED 501 AM CDT SAT APR 18 2015/
DISCUSSION...
HEAVY RAINS OVERNIGHT SO FAR HAVE BEEN CONFINED MAINLY TO
SOUTHERN JEFFERSON COUNTY IN SOUTHEAST TEXAS WITH 3-4 INCHES OF
RAIN MAINLY SOUTH OF URBAN AREAS...TO 2 TO 3 INCHES IN NORTHWEST
CAMERON PARISH OVER THE MARSHES. OTHERWISE...1 TO 2 INCH RAINS
WERE COMMON FROM OPELOUSAS...WEST TO DEQUINCY...TO ORANGE AND
VILLAGE MILLS. THE NORTHERN AREAS HAVE BEEN SPARED THIS TIME
AROUND.
THE BIG QUESTION TODAY IS THE AMOUNT OF AVAILABLE MOISTURE AND
INSTABILITY NEEDED TO CONTINUE THE FLASH FLOOD WATCH AND OF
COURSE THE RISK OF SEVERE STORM DEVELOPMENT. THE ATMOSPHERE HAS
BEEN WORKED OVER PRETTY WELL...AND THE CONVECTION OVER THE COASTAL
WATERS FROM 40NM TO WELL BEYOND 60NM HAS DIVERTED THE DEEP GULF
MOISTURE FURTHER SOUTH WAY FROM AREA. THERE IS A GOOD PLUME OF
CLOUDS BLOWING OFF GULF CONVECTION SWEEPING NORTHWARD ACROSS AREA
TODAY. ON THE OTHER HAND...SOUNDING FORECAST PROFILES SHOW
PRECIPITABLE WATER VALUES HOLDING ABOVE 1.5 INCHES OR BETTER AT
LEAST UNTIL 00Z AND THEN DROP OFF. THEREFORE...WILL NOT MENTION
SEVERE THUNDERSTORMS IN THE FORECAST AS THE RISK FROM SPC IS
SLIGHT. CLOUDS MAY HINDER INSTABILITY FOR MOST OF THE DAY ANYWAY.
HOWEVER...CANNOT RULE OUT AN ISOLATED BRIEF SEVERE MID TO LATE
AFTERNOON SOMEWHERE...BUT THAT WOULD BE ISOLATED IF ANY.
THE FLASH FLOOD WATCH COULD BE LIFTED TODAY IF IT WERE NOT FOR
THE SATURATED SOILS AND FILLED DITCHES. REALLY BELIEVE THAT THE
FIRST HALF OF THE MORNING THERE IS LITTLE OF ANY THREAT OF HEAVY
RAINS...HOWEVER IN THE AFTERNOON...COULD SEE SOME REDEVELOPMENT OF
HEAVIER RAINS FROM UPSTREAM INSTABILITY...THEREFORE...WILL LEAVE
FLASH FLOOD WATCH UP FOR NOW AS IT WOULD NOT BE PRUDENT TO MOVE IT
JUST YET.
THE UPPER LEVEL LOW SPINNING ACROSS COLORADO THIS MORNING WITH THE
SOUTHERLY TROUGH EXTENDING INTO THE SOUTH CENTRAL SOUTHERN
STATES...WILL CONTINUE TO MIGRATE EASTWARD OVER THE NEXT 48 HOURS.
AS IT DOES...DEEP MOISTURE AND ENERGY WILL SHIFT EASTWARD DURING
THIS PERIOD. THEREFORE...DO EXPECT TO SEE A BIG DROPOFF IN RAIN
CHANCES ON SUNDAY BUT KEEP LOW POPS IN AS AS FRONT SWEEPS THROUGH
THE AREA LATE SUNDAY NIGHT INTO MONDAY. THE FRONT WILL RETURN AS A
WARM FRONT BY MIDWEEK AND THEREFORE WILL GET A BUMP UP IN POPS AS
THE WARM FRONTAL BOUNDARY MOVES NORTHWARD. RAIN CHANCES ONCE AGAIN
FALL BY THE END OF THE WEEK AS THE REGION WILL REMAIN BETWEEN
SYSTEMS.
MARINE...
AM WIDESPREAD CONVECTION WILL END FROM WEST TO EAST THIS MORNING.
REDEVELOPMENT COULD BEGIN LATER THIS AFTERNOON BUT PROBABLY WILL
NOT BE QUITE AS BAD AS THE LAST COUPLE OF DAYS HAVE BEEN. ONSHORE
FLOW WILL CONTINUE WITH PERIODIC DISRUPTION DUE TO THUNDERSTORMS
AND OUTFLOWS.
06
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 77 64 82 61 / 80 50 20 20
LCH 77 65 82 64 / 80 40 20 20
LFT 78 66 84 65 / 90 60 30 20
BPT 78 65 82 64 / 70 40 20 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>033-
041>045-052>055-073-074.
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
1118 AM CDT SAT APR 18 2015
.DISCUSSION...
MOST OF THE MODELS ARE NOT HANDLING THE ONGOING PRECIP VERY WELL
DEPICTING WAY TOO MUCH COVERAGE COMPARED TO WHAT IS ACTUALLY
OCCURRING. LACK OF PRECIP BACK TO THE SW ALSO LENDS LOW CONFIDENCETO
THE MODELS. HRRR SEEMS TO BE PERFORMING SLIGHTLY BETTER SO HAVE
TRIMMED POPS SLIGHTLY BASED ON THE MORE SCATTERED COVERAGE
EXPECTED BY THE HRRR ACROSS MAINLY THE NERN HALF OF THE CWA
THROUGH THE REMAINDER OF TODAY. STARTING TO SEE A FEW BREAKS IN
THE CLOUDS WHICH WILL HELP TEMPS TO WARM QUICKLY. INSTABILITY WILL
BE SUFFICIENT TO SUPPORT AT LEAST AN ISOLATED SEVERE THREAT IN
PLACE.
OTHERWISE...ONLY A FEW MINOR CHANGES WERE MADE TO DEWPOINT AND
WIND GRIDS BASED ON LATEST OBS. UPDATED PRODUCTS HAVE BEEN SENT.
/09/
&&
.PREV DISCUSSION... /ISSUED 652 AM CDT SAT APR 18 2015/
AVIATION...
SEEING QUITE A SPREAD IN CIGS THIS MORNING...WITH IFR CIGS OVER
NCNTRL LA AS WELL AS PORTIONS OF DEEP E TX...WITH A MIX OF
MVFR/VFR CIGS ELSEWHERE ACROSS THE REGION. A WEAK SFC WAVE HAS
DEVELOPED ALONG A STATIONARY FRONT OVER EXTREME ERN TX...AND
SHOULD SHIFT ENE INTO NRN LA THIS MORNING...RESULTING IN THE
DEVELOPMENT OF LOW MVFR/IFR CIGS BY MIDMORNING OVER NW LA/SW AR.
SCT -SHRA AND ISOLATED -TSRA CONTINUE TO DEVELOP OVER PORTIONS OF
E TX/SE OK/ADJACENT SW AR THIS MORNING...WITH THIS TREND EXPECTED
TO CONTINUE/SPREAD FARTHER E ACROSS NCNTRL LA/SCNTRL AR THIS
MORNING BEFORE GRADUALLY DIMINISHING FROM SW TO NE THIS AFTERNOON.
HAVE TEMPOED MENTION OF SHRA INTO THE N LA/SW AR TERMINALS THIS
MORNING...BUT LOW CONFIDENCE PRECLUDES MENTION FOR THE AFTERNOON.
WHILE CIGS WILL BE SLOW TO IMPROVE TODAY OVER N LA/SW AR NEAR THE
SFC FRONTAL WAVE...SHOULD SEE CIGS IMPROVING TO VFR BY MID-
AFTERNOON ACROSS E TX...SCATTERING OUT BY 00Z SUNDAY. COULD ALSO
SEE THE RETURN OF IFR/MVFR CIGS LATE IN THE TAF PERIOD ACROSS E
TX/N LA JUST PRIOR TO DAYBREAK SUNDAY...WITH THESE CIGS EXPECTED
TO SPREAD FARTHER NNE SHORTLY THERE AFTERWARDS. VRB WINDS 6KTS OR
LESS TODAY WILL BECOME LT/VRB AFTER 00Z. /15/
PREV DISCUSSION... /ISSUED 538 AM CDT SAT APR 18 2015/
DISCUSSION...
MOSTLY CLOUDY WITH MID TO UPPER 60S AND VARIABLE WINDS OVER THE
FOUR STATE AREA. THE KSHV 88D RADAR IS SHOWING MOST COVERAGE OF
SHOWER AND ISOLATED THUNDERSTORMS OVER OUR OKLAHOMA AND TEXAS
COUNTIES WITH DEPARTING COVERAGE FOR NOW OVER NORTH CENTRAL
LOUISIANA AND SOME OF THE TEXAS SOUTHERN FLANK PULLING ACROSS
TOLEDO BEND. OVERNIGHT...WE WERE CUT OFF FROM DECENT GULF
MOISTURE BY A LARGE THUNDERSTORM COMPLEX MOVING EAST ALONG I-10.
LOOKING AT THE WATER VAPOR...THE THICK BELT OF PACIFIC MOISTURE
IS STILL BACK ACROSS SOUTH TEXAS...AND LIFTING THIS WAY.
MEANWHILE...THE UPPER LOW IS SLOWLY EDGING OFF THE FOUR CORNERS
INTO CO/NB/KN NOW THANKS TO ANOTHER DEEPENING TROUGH ON THE NW
COAST. THE COLD FRONT WILL NOT ARRIVE UNTIL LATE AFTERNOON SUNDAY
AND INTO THE EVENING. SO TODAY LOOKS MORE FAVORABLE FOR WIDE
SPREAD COVERAGE WITH ONLY A MARGINAL RISK FOR SEVERE AND THEN ON
SUNDAY WE ARE SLIGHT/ENHANCED FOR SEVERE WITH THE COLD FRONT BY
MORE LIMITED WIDE SPREAD COVERAGE. OUR DEW POINTS WILL BE LOW TO
MID 60S WITH SOME MORE HEATING AHEAD OF THE FRONT ARRIVING WITH
SOME LIFT WHILE STILL UNDER THE UPPER DIVERGENT TROUGH TO OUR
WEST. SPC IS LOOKING FOR ANOTHER MCS BY LATE SUNDAY AFTERNOON AND
MOVING EAST QUICKLY INTO THE EVENING WHILE THE MODELS ARE ALL OVER
THE PLACE WITH QPF. LITTLE CHANGE WITH A COOL DOWN BACK TO NORMAL
FOR THE NEW WORK WEEK AND THEN ANOTHER FRONT MID TO LATE WEEK.
/24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 77 62 83 56 / 50 50 20 20
MLU 76 63 81 58 / 60 60 40 30
DEQ 76 58 79 50 / 40 40 30 10
TXK 75 59 80 53 / 50 40 30 20
ELD 75 60 81 54 / 50 50 40 30
TYR 78 61 82 53 / 20 40 20 10
GGG 77 61 82 54 / 30 40 20 10
LFK 78 64 85 57 / 30 50 20 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1215 PM EDT SAT APR 18 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 AM EDT SAT APR 18 2015
ANOTHER SUNNY DAY IS EXPECTED TODAY WITH HIGHS AROUND 70. LOW
PRESSURE WILL MOVE NORTH FROM THE GULF AREA SUNDAY BRINGING QUITE A
BIT OF RAIN WITH IT. AFTER THE LOW MOVES EAST...COLDER AIR WILL MOVE
OVER LOWER MICHIGAN AND REMAIN IN PLACE NEXT WEEK. HIGHS WILL ONLY
REACH THE MID 40S TO MID 50S NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1055 AM EDT SAT APR 18 2015
I INCREASED THE HIGH TEMPERATURE AROUND 5 DEGREES FOR THIS
AFTERNOON BASED ON MORNING SOUNDING DATA. THE RAP MODEL SEEMS TO
BE DOING A BETTER JOB OF SHOWING CURRENT TEMPERATURES...DEW POINTS
AND WINDS SO I USED THAT TO INCREASE THE WIND SPEED...TEMPERATURES
AND LOWER THE DEW POINTS. THAT ALL BEING SO... WE COULD SEE HIGHS
IN THE MID TO UPPER 70S OVER THE WESTERN SECTIONS OF THE CWA THIS
AFTERNOON. WE WILL BE GETTING CLOSE TO RED FLAG CONDITIONS IF THIS
HAPPENS. FOR NOW I WILL LET OUR HWO AND POST OF FACEBOOK COVER
THIS ISSUE.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EDT SAT APR 18 2015
FORECAST CONCERNS DEAL WITH THE LOW APPROACHING SUNDAY. AFTER
ANOTHER SUNNY AND MILD DAY TODAY CLOUDS WILL INCREASE TONIGHT AS A
PHASED NORTHERN/SOUTHERN STREAM LOW APPROACHES FROM THE SOUTH.
STRONG 60KT LLJ WILL DRAW UP ABUNDANT MOISTURE INTO THE SYSTEM.
STRONG ISENTROPIC LIFT LATE SUNDAY MORNING WILL LEAD TO RAPID RAIN
DEVELOPMENT FROM SOUTH TO NORTH. LOOK FOR THE WIND TO INCREASE AS
WELL...AT LEAST UNTIL THE LOW MOVES OVERHEAD SUNDAY EVENING. SHORT
RANGE MODELS HAVE BEEN CONSISTENT MOVING THE LOW DIRECTLY OVER THE
CWA SO CONFIDENCE IS PRETTY HIGH WE/LL SEE RAIN. QPF AROUND 3/4 INCH
LOOKS POSSIBLE AS MIXING RATIOS CLIMB TO 8G/KG BY LATE SUNDAY
AFTERNOON. THERE STILL ISN/T A STRONG SIGNAL FOR THUNDER SO WE KEPT
IT OUT OF THE GRIDS. HOWEVER GIVEN A SLIGHT DECREASE IN STABILITY
NOTED WE CAN/T RULE IT OUT EITHER.
MONDAY WILL BE MUCH COOLER AS THE LOW MOVES EAST AND WEST WINDS
DEVELOP. HIGHS IN THE MID 50S ARE EXPECTED. THE UPPER LOW WILL MOVE
OVER THE CWA MONDAY SO WE/LL CONTINUE TO SEE SCATTERED SHOWERS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EDT SAT APR 18 2015
MOST OF NEXT WEEK WILL BE COLDER THAN NORMAL WITH SCATTERED RAIN OR
MIXED RAIN AND SNOW SHOWERS AS AN UPPER LOW BECOMES PARKED OVER THE
NORTHERN GREAT LAKES REGION. DEEP CYCLONIC FLOW AND COLD ADVECTION
WILL LEAD TO CONSIDERABLE CLOUDINESS WITH HIGHS ONLY IN THE 40S AND
FREQUENTLY BREEZY CONDITIONS.
THE MAIN RISK FOR SNOW SHOWERS WILL BE AT NIGHT AND DURING THE EARLY
MORNING WHEN THE BOUNDARY LAYER IS COOLEST... ESPECIALLY FOR HIGHER
ELEVATIONS NEAR AND NORTH OF ROUTE 10 WHERE SOME LIGHT ACCUMULATIONS
EVEN APPEAR POSSIBLE.
GFS/ECMWF DO NOT LOOK PARTICULARLY BULLISH WITH QPF AT ANY TIME NEXT
WEEK ALTHOUGH SPOKES OF VORTICITY ROTATING AROUND THE UPPER LOW
MAY LEAD TO OCCASIONAL BOUTS OF INCREASED COVERAGE OF HEAVIER
SHOWERS.
THINGS APPEAR TO DRY OUR THURSDAY NIGHT AND FRIDAY WHEN THE UPR LOW
MOVES EAST AND SFC RIDGING ARRIVES FROM THE WEST. BY FRIDAY HIGHS
COULD BE BACK UP INTO THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1215 PM EDT SAT APR 18 2015
VFR CONDITIONS WILL CONTINUE THROUGH 18Z SUNDAY. ENE WINDS WILL GUST
TO AROUND 20 KTS AT TIMES THIS AFTERNOON AND BECOME EASTERLY AND
GUST TO 20 TO 25 KTS SUNDAY MORNING AND AFTERNOON. SHOWERS WILL
GRADUALLY MOVE IN FROM SOUTH TO NORTH AT ALL THE TERMINALS BETWEEN
18Z AND 21Z SUNDAY AFTERNOON WHEN CONDITIONS WILL DETERIORATE TO
PRIMARILY MVFR WITH POCKETS OF IFR POSSIBLE IN HEAVIER SHOWERS.
&&
.MARINE...
ISSUED AT 328 AM EDT SAT APR 18 2015
A COLD FRONT WILL MOVE THROUGH EARLY TODAY AND TURN THE WINDS TO THE
NORTHEAST. THE OFFSHORE FLOW WILL CONTINUE TONIGHT AND STRENGTHEN. A
SCA MAY BE NEEDED TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 1126 AM EDT SAT APR 18 2015
A GOOD SOAKING RAINFALL IS STILL ON TRACK TO AFFECT THE ENTIRE AREA
BEGINNING SUNDAY. THE BULK OF THE MOISTURE WILL LIKELY FALL
BETWEEN SUNDAY AFTERNOON INTO MONDAY MORNING WITH SOME GUIDANCE
HINTING AT OVER AN INCH IN SPOTS. ADDITIONAL CHANCES FOR RAIN WILL
SPAN THROUGH THE MIDDLE OF THE WEEK BUT ARE NOT EXPECTED TO BE
QUITE AS ABUNDANT WITH MOISTURE.
RIVERS WILL MAINLY RESPOND IN THE MANNER OF MINOR RISES. THIS SHOULD
MOSTLY CONSIST OF WITHIN BANK RISES. I HAVE A LITTLE MORE CONFIDENCE
IN THINKING MAPLE RAPIDS COULD FLIRT WITH ADVISORY CRITERIA ONCE
AGAIN.
THIS IS PENDING THE AMOUNT OF RAINFALL RECEIVED THROUGH EARLY MONDAY.
OTHERWISE...WE ARE LOOKING PRETTY GOOD WITH THIS NOT BEING A
CONVECTIVE
MODE OF PRECIPITATION...NO REAL SURPRISES AT THIS POINT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...LAURENS
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1200 PM CDT SAT APR 18 2015
.UPDATE... IN THE PAST HOUR OR TWO IT IS BECOMING INCREASINGLY
APPARENT THAT DEEP CONVECTION STRETCHING FROM THE NORTH CENTRAL GULF
TO THE WESTERN GULF IS REALLY GOING TO HAMPER VIGOROUS THUNDERSTORM
DEVELOPMENT OVER THE LOWER MS VALLEY LATE TODAY INTO THIS EVENING.
STILL NOT CONVINCED THAT MOISTURE...LIFT AND INSTABILITY INGREDIENTS
WILL NOT BE ENOUGH AT LEAST ALONG AND SOUTHEAST OF THE NATCHEZ TRACE
CORRIDOR TO GET A FEW SEVERE STORMS GOING EVENTUALLY WITH A HEAVY
RAIN THREAT PERSISTING AS WELL. FOR THAT REASON WE HAVE DOWNPLAYED
SEVERE POTENTIAL IN ALL AREAS THROUGH THE REST OF TODAY AND INTO
TONIGHT IN ALL AREAS (ALTHOUGH KEEPING SOME RISK GOING IN THE
SOUTHEAST HALF OF THE CWA). WE WILL WATCH TRENDS CLOSELY TO ADJUST
WITH THE AFTERNOON UPDATE. /BB/
&&
.PREV DISCUSSION... /ISSUED 1025 AM CDT SAT APR 18 2015/
UPDATE... THINGS THIS MORNING ARE EVOLVING GENERALLY AS
ANTICIPATED...ALTHOUGH QUESTION MARKS GOING INTO LATE TODAY STILL
PERSIST IN SOME MEASURE OWING TO THUNDERSTORMS ANCHORED TO THE SE LA
COAST. THESE STORMS WERE PREVIOUSLY SPREADING A LIGHT RAIN SHIELD
INTO MY SOUTHERN ZONES...BUT THE NORTHWARD EXTENT OF THIS PRECIP HAS
SHRUNK IN THE LAST FEW HOURS. ALSO...VIGOROUS STORMS JUST SOUTH OF
THE COAST HAVE BEEN GRADUALLY LOSING COVERAGE SINCE DAYBREAK AND
THEY SHOULD EBB QUICKLY INTO MIDDAY AS UPPER JET PULLING BACK TO THE
WEST REMOVES MUCH OF THE UPPER LEVEL SUPPORT. HOWEVER...IF SAID
EVOLUTION DOES NOT COME TO PASS WITH HASTE THEN MOISTURE TRANSPORT
BLOCKING AND CLOUD COVER INTO SOME OF MY SOUTHERN ZONES WILL HINDER
POTENTIAL FOR VIGOROUS INLAND THUNDERSTORM FORMATION AS WE GO INTO
THIS AFTERNOON.
BUT ASSUMING THE LATTER CAVEAT IS NOT AN ISSUE...LATEST HRRR AND
DOWNSCALED NAM RUNS POINT TO WORRISOME STORMS MOVING INTO MY
SOUTHERN ZONES (ESPECIALLY SOUTH CENTRAL AND SE MS) ZONES FROM MID
AFTERNOON THROUGH MID EVENING. ATMOSPHERIC LAPSE RATES WILL MAINLY
BE AT OR LESS THAN 6 C/KM IN THE H700-H500 LAYER BUT MLCAPE PEAKING
OVER 1000 J/KG SHOULD BE SUFFICIENT GIVEN EXPECTED LOW LEVEL AND
DEEP LAYER SHEAR TO PRODUCE ORGANIZED STORMS. ONCE AGAIN...A FEW
TORNADOES CANNOT BE RULED OUT.
THERE IS NOT ENOUGH EVIDENCE YET TO GO CHANGING THE PREVIOUS
FORECAST AND SEVERE WEATHER EXPECTATIONS MUCH. HOWEVER...WE WILL BE
WATCHING TRENDS CLOSELY OVER THE NEXT FEW HOURS AND WILL SEE IF VERY
RECENT HRRR HINTS THAT SEVERE RISK WILL BE STRONGLY FOCUSING
SOUTHEAST OF THE NATCHEZ TRACE APPEAR SOLID. IF THAT IS THE CASE WE
WILL UPDATE ACCORDINGLY...BUT EVEN IF WE DO FOCUS THE SEVERE RISK
EVEN MORE CONSIDERABLY IN SOUTHERN ZONES THE RISK OF LOCALIZED
FLOODING PROBLEMS STILL LOOKS TO EXTEND ACROSS A MUCH LARGER PORTION
OF THE FORECAST AREA. /BB/
AVIATION...IFR CATEGORY STRATUS PREVAILS ACROSS THE TAF SITES THIS
MORNING WITH SHOWERS MOVING ACROSS HBG. EXPECT THESE CONDITIONS TO
PERSIST UNTIL LATE MORNING/EARLY AFTERNOON BEFORE FINALLY MIXING
OUT. SHRA WILL MOSTLY CONFINED TO LOCATIONS SOUTH OF THE HEZ-HBG
CORRIDOR THIS MORNING AS A CONVECTIVE COMPLEX SLIDES EASTWARD ALONG
THE COAST...BUT A NEW ROUND OF SHRA/TSRA IS EXPECTED BY MID/LATE
AFTERNOON LASTING INTO THE EVENING WITH AN APPROACHING DISTURBANCE.
THERE MAY BE A WINDOW OF OPPORTUNITY FOR BETTER FLYING CONDITIONS
DURING THE EARLY AFTERNOON...FOLLOWED BY POOR FLYING CONDITIONS
PERSISTING FROM MID/LATE AFTERNOON THROUGH THE EVENING.
/EC/15/
PREV DISCUSSION... /ISSUED 454 AM CDT SAT APR 18 2015/
SHORT TERM...TODAY THROUGH TONIGHT...AN ACTIVE WEATHER WEEKEND IS
IN STORE AS TWO ROUNDS OF SEVERE WEATHER ARE EXPECTED TO IMPACT THE
ARKLAMISS. THE FIRST ROUND WILL BE INITIATED BY INCREASINGLY
FAVORABLE CYCLONIC AND SHEARED FLOW DEVELOPING OVER THE LOWER MS
VALLEY REGION LATER THIS AFTERNOON AND EVENING. THE CONVECTIVE SYSTEM
CURRENTLY MOVING EAST ALONG THE THE LA COAST WILL DELAY TIMING OF THE
MORE SIGNIFICANT THUNDERSTORM ACTIVITY UNTIL MID/LATE AFTERNOON...BUT
VERY MOIST AND UNSTABLE AIR WITH PRECIPITABLE WATER VALUES > 1.75
INCHES AND ML CAPE NEAR 1000 J/KG SHOULD BE AVAILABLE FOR VIGOROUS
CONVECTIVE DEVELOPMENT AT THAT TIME. WITH DEEP LAYER AND LOW LEVEL
SHEAR ON THE INCREASE...STILL EXPECT ORGANIZED STORMS TO DEVELOP WITH
THE MOST FAVORABLE SET-UP FOR SEVERE WEATHER AND HEAVY RAINFALL
ALONG/SOUTH OF THE I-20 CORRIDOR...BUT WILL SAY THAT CONFIDENCE IS A
LITTLE SHAKIER NOW ON THIS SCENARIO BASED ON RECENT HIGH RES GUIDANCE
TRENDS. IF THE NEXT ROUND OF CONVECTIVE DOES NOT MATERIALIZE AS
ANTICIPATED DUE TO THE MORNING CONVECTION...OR IF IT DEVELOPS FARTHER
EAST...THEN IT IS POSSIBLE THAT MORE ROBUST CONVECTION WOULD IMPACT
NORTHERN PORTIONS OF THE ARKLAMISS AND THIS COULD ALLOW THE SEVERE
WEATHER/HEAVY RAINFALL THREAT TO SHIFT FARTHER NORTH AS WELL. STAY
TUNED FOR UPDATES TO THIS FORECAST LATER THIS MORNING AS CONVECTIVE
EVOLUTION HOPEFULLY BECOMES A LITTLE MORE CLEAR. /EC/
SUNDAY THROUGH SUNDAY NIGHT...MODELS FOR SUNDAY CONTINUE TO SUPPORT
THE RISK FOR SEVERE STORMS ALONG WITH SOME POTENTIAL FOR A HIGHER END
EVENT. WHAT IS STARTING TO BECOME MORE CLEAR IS MUCH OF THE DAY LOOKS
TO BE IN A LULL FROM CONVECTION AFTER MORNING ACTIVITY DEPARTS TO THE
EAST AND THE ROUND OF STORMS WILL BE MORE FOCUSED LATER BETWEEN A 5PM
TO 3AM WINDOW. IN THE WAKE OF THE SAT SYSTEM...MUCH STEEPER LAPSE
RATES WILL SPREAD OVER THE AREA (7.0 TO 7.5 C/KM)(29-31C VERTICAL
TOTALS). ALOFT MUCH COLDER TEMPS WILL MOVE IN WITH H5 READINGS OF -15
TO - 16C. THIS WILL ALL SUPPORT SBCAPE OF 2000-3000 J/KG AS SFC
HEATING REACHES AROUND 80 DEGREES. THIS WILL ALL SUPPORT VIGOROUS
STORMS WITH ROBUST UPDRAFTS. CONCURRENT WITH THIS WILL BE AN OVERALL
DRIER ATMOSPHERE COLUMN AS WELL WITH PWS AROUND 1.2 INCHES. THIS WILL
LEND TO KEEPING STORMS MORE DISCRETE ALONG WITH AN EASTWARD DEEP
LAYER (0-6KM) SHEAR VECTOR OF 40-50KTS. EXPECTATIONS ARE FOR NOT MANY
(ISO/SCT) SUPERCELLS THAT WILL PACK QUITE THE PUNCH. LARGE HAIL >
GOLF BALL SIZE APPEARS VERY POSSIBLE ALONG WITH DAMAGING WINDS WHICH
ALSO COULD BE HIGHER END. DUE TO THIS POSSIBILITY OF SEEING
SIGNIFICANT TYPE WEATHER (>2 IN HAIL)...WILL UP OUR OUTLOOK TO SIG
OVER A DECENT PORTION OF THE NW. ELSEWHERE THE OUTLOOK WILL REMAIN
SIMILAR AS STORMS MAY LOSE SOME POTENCY AS THEY PUSH FURTHER EAST AND
GET LATER INTO THE OVERNIGHT. /CME/
LONG TERM...MONDAY THROUGH SATURDAY....MONDAY MORNING THE LARGE
CLOSED LOW IS EXPECTED TO BE CENTERED OVER THE UPPER MISSISSIPPI
VALLEY WITH ASSOCIATED LARGE AMPLITUDE UPPER LEVEL TROUGHING OVER
THE EASTERN TWO THIRDS OF THE CONUS. MODELS AGREE THAT THE
ASSOCIATED SURFACE LOW WILL BE OVER THE WESTERN GREAT LAKES REGION
MONDAY MORNING BUT THERE ARE TIMING DIFFERENCES WITH THE TRAILING
COLD FRONT THAT IS EXPECTED TO BE OVER SOUTHEAST MISSISSIPPI.
CONSENSUS PLACES THIS COLD FRONT AND THE BULK OF THE PRECIPITATION
JUST SOUTHEAST OF OUR CWA AT DAYBREAK BUT WL MAINTAIN LOW CHANCES OF
LIGHT RAIN IN OUR NORTHEAST THROUGH MID MORNING AS A WEAK SHORTWAVE
PASSES OVER OVERHEAD. DRY WEATHER IS EXPECTED AREAWIDE BY NOON.
SLIGHTLY COOLER AND MUCH DRIER AIR WILL FILTER INTO OUR CWA MONDAY
KNOCKING DEW POINTS INTO THE 40S DURING THE AFTERNOON. DRY WEATHER
IS EXPECTED TO LAST OVER OUR CWA THROUGH TUESDAY AS A SURFACE HIGH
MOVES EAST ACROSS OUR AREA. THIS SURFACE HIGH WILL SHIFT EAST
WEDNESDAY AND THE RESULTING RETURN FLOW WILL INCREASE MOISTURE TO
SUPPORT RAIN CHANCES AGAIN FROM THE WEST BY WEDNESDAY AFTERNOON.
WARMER THAN NORMAL TEMPERATURES AND GREATER RAIN CHANCES ARE
EXPECTED FOR THE END OF THE WEEK BUT THERE ARE SIGNIFICANT
DIFFERENCES IN THE MODELS WITH SOME MAIN FEATURES. THE NORTHERN
CLOSED LOW WILL MOVE SLOWLY EAST ACROSS THE GREAT LAKES REGION
TUESDAY AND WEDNESDAY AND BE OVER THE NEW ENGLAND STATES BY FRIDAY.
THIS LOW WILL TRY TO HELP SUPPORT ANOTHER COLD FRONT DROPPING INTO
OUR CWA THURSDAY INTO FRIDAY BUT INDUCED SHORTWAVE RIDGING
DOWNSTREAM OF A SECOND CLOSED LOW MOVING OVER THE DESERT SOUTHWEST
THURSDAY LOOKS TO IMPEDE THE COLD FRONT INTO OUR AREA. SHORTWAVES
ROUNDING THE BASE OF THE SOUTHERN CLOSED LOW LOOK TO COMBINE WITH
INCREASING MOISTURE AND DAYTIME HEATING FOR A ROUND OF CONVECTION
THURSDAY AND FRIDAY. BOTH GFS AND ECMWF OPEN THE CLOSED LOW AND
BRING THE REMAINING SHORTWAVE TROUGH ACROSS OUR REGION SATURDAY BUT
DIFFER ON THE SURFACE FEATURES WITH THE GFS DEPICTING A MUCH DEEPER
LOW AND STRONGER COLD FRONT ACROSS OUR AREA. FOR NOW...GREATEST POPS
THROUGH THE LONG TERM WILL BE CARRIED FRIDAY AND FRIDAY NIGHT. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 75 64 81 61 / 84 66 31 39
MERIDIAN 76 65 82 64 / 71 83 37 34
VICKSBURG 73 64 81 59 / 86 49 34 46
HATTIESBURG 77 66 84 65 / 86 78 33 28
NATCHEZ 75 64 82 60 / 91 54 28 42
GREENVILLE 73 63 81 57 / 58 47 49 57
GREENWOOD 74 63 79 59 / 56 55 44 56
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
JAN
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1243 PM CDT Sat Apr 18 2015
.DISCUSSION...
Issued at 411 AM CDT SAT APR 18 2015
Overview: Closed and cut-off upper low now over central CO will be
the primary weather driver for the weekend. Feature will open up by
Sunday and move east in response to a shortwave trough digging
southeast through the Northern Rockies. Expect to see a several
rounds of active convection Saturday and Sunday.
Today - Sunday:
While eyes have been fixated on the closed upper low now over CO/NM
the real weather makers will be periodic vorticity lobes and
associated layered frontogenesis that rotate northeast out from
under the upper low. Little going on over the CWA early this morning
as we`re lacking any discernible feature to initiate any convection.
But we are finally seeing the long awaited next round of convection.
Regional radars have recently lit up from OK northward through
central KS albeit further west than we`ve been expecting. Favor
following the HRRR reflectivity trends, which have slowed down the
arrival of the KS/OK convection and latest NAM mass fields/h7
vorticity prog. Thus have pared back PoPs significantly for first
part of morning and slowed the eastward expansion of precipitation.
Even still this is a forecast which will need adjusting throughout
the day as the convection tied to the upper low has had repeated
false starts as well as expanding too fast to the east.
Thickening cloud cover and rain-cooled air will affect temperatures
over the western half of the CWA more so than the eastern half where
precipitation will move in later in the day. Precipitable water
values around two standard deviations above normal suggest potential
for 1"+ rains through tonight. Weak shear and MUCAPEs under 1000J/kg
favor convection remaining below severe limits.
Should see a lull in the rain later tonight and first part of Sunday
before the next wave of convection moves in. The upper low will have
opened up by then and will accelerate eastward. Anticipate convection
increasing as it moves east through the CWA in response to improving
upper level dynamics and low-level convergence associated with a
cold front. However, once again the 0-6km shear of 20-25kts and
modest MUCAPEs favor convection being sub-severe.
Monday - Tuesday:
A fairly deep upper trough stretching from MN through the Mid MS
Valley will influence our weather with widespread subsidence on the
backside of the trough. Abundant solar insolation will help offset
cold air advection but still result in below average temperatures.
Wednesday - Friday:
As the upper trough shifts east through the Great Lakes an upper
ridge will build eastward through the Rockies and into the
Central/Southern Plains. Medium range models are in agreement that a
cold front will surge through the region on Wednesday. However, they
disagree on whether or not convection will be generated. Moisture
fields look minimal and believe any shower activity will be widely
scattered.
As we get into Thursday and Friday the ECMWF and GFS both lift a
shortwave out of the southwestern U.S. but the GFS appears
unrealistic in deepening a surface over the Central High Plains and
spreading warm advection convection too far downstream. Will use a
blended forecast but overall confidence low for Thursday`s PoPs but
timing looks better for the PoPs on Friday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1240 PM CDT SAT APR 18 2015
Light to moderate rain, with perhaps an isolated, brief pocket of
heavy rain will move through the area through the next few hours.
There could be a couple isolated rumbles of thunder, but overall the
threat for lightning/thunder is minimal with this activity. There
will likely be a lull in the rain through the evening and
overnight hours, before another round picks up on Sunday morning.
Expect some spotty activity prior to sunrise Sunday, with confidence
rising in widespread moderate rain by the late morning to early
afternoon hours.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
DISCUSSION...MJ
AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
259 PM CDT SAT APR 18 2015
.SYNOPSIS...
ISSUED AT 255 PM CDT SAT APR 18 2015
ANALYSIS OF THE 19Z MSL DATA SHOWED LOW PRESSURE CENTERED IN WESTERN
KANSAS WITH A WARM FRONT ACROSS NORTHERN KANSAS...A COLD FRONT INTO
THE OKLAHOMA/TEXAS PANHANDLE AND AN INVERTED TROUGH FROM SOUTHWEST
TO NORTH CENTRAL NEBRASKA. IN THE UPPER LEVELS...THE WATER VAPOR
IMAGERY SHOWED A CLOSED CYCLONIC CIRCULATION LOCATED IN EASTERN
COLORADO.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 255 PM CDT SAT APR 18 2015
THE CENTER OF STRONG CUT OFF LOW /H500 MB TEMP -25C/ IS NEAR AKRON
COLORADO THIS AFTERNOON. HIGH RES MODELS INSIST THAT
CONVECTION...AIDED BY A SIGNIFICANT PV ANOMALY ROTATING NORTHEAST
INTO WESTERN KANSAS AROUND THE LOW CENTER...WILL DEVELOP ONCE AGAIN
ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA LATE THIS AFTERNOON
AND THIS EVENING. THE ACTIVITY WILL GROW UPSCALE MUCH LIKE LAST
NIGHT AS IT MOVES NORTH/NORTHEAST INTO THE REST OF WESTERN...CENTRAL
AND NORTH CENTRAL NEBRASKA TONIGHT.
AS FAR AS SEVERE POTENTIAL...GOOD SURFACE HEATING UNDERWAY ATTM
ACROSS SOUTHWEST NEBRASKA AND NORTHWEST KANSAS. EXPECTING MUCAPE ON
THE ORDER OF 1500 J/KG BY LATE AFTERNOON INTO THE EVENING HOURS. ONE
WEAKNESS ARE THE WIND FIELDS ARE FAIRLY LIGHT...AND NOT A A LOT OF
VEERING WITH HEIGHT. NEVERTHELESS WITH THE STEEP LOW AND MID LEVEL
LAPSE RATES...WILL SEE SOME VIGOROUS UPDRAFTS...AND SOME HAIL LIKELY
WITH THOSE STRONGER UPDRAFTS. TORNADO POTENTIAL IS NOT ZERO...BUT
AGAIN WITH THE WEAK WIND FIELDS AND LIMITED VEERING...NOT EXPECTING
THAT TO BE THE PRIMARY RISK. IF A TORNADO OCCURS IT WOULD MORE THAN
LIKELY BE WEAK. K INDICES ARE HIGH...AND LOCALLY HEAVY RAINFALL
WILL BE POSSIBLE.
THE CLOSED H500 MB CIRCULATION IS FORECASTED TO MIGRATE INTO
NORTHWEST KANSAS BY SUNDAY MORNING...AND CONTINUE EAST ACROSS KANSAS
DURING THE DAY. A SMALL DEFORMATION BAND OF PRECIPITATION IS LIKELY
ON THE NORTH AND WEST SIDE OF THE TRACK. THE EXACT TRACK OF THE LOW
CENTER IS UNCERTAIN...AS CONVECTION LIKELY TO INFLUENCE THE MASS
FIELD AND EXPECT THE FINAL TRACK COULD END UP A LITTLE FARTHER
NORTH. THIS IS HINTED IN THE LATEST RUN OF THE RAP MODEL. OTHERWISE
A COLD FRONT ASSOCIATED WITH A SEPARATE NORTHERN STREAM SYSTEM WILL
CRASH THROUGH THE AREA...BRINGING GUSTY NORTHWEST WINDS TO THE
REGION.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 255 PM CDT SAT APR 18 2015
MEDIUM RANGE...(SUNDAY NIGHT THROUGH TUESDAY)
THE UPPER LEVEL LOW ACROSS COLORADO WILL LIFT OUT AND COLLIDE WITH
AN UPPER LEVEL SHORT WAVE ACROSS ACROSS THE NORTHERN GREAT LAKES
FORMING A VERY LARGE CLOSED UPPER LOW. UPSTREAM HEIGHTS RISE SHARPLY
ACROSS NRN CANADA SUPPORTING A BROAD AREA OF HIGH PRESSURE WHICH
CIRCULATE COOL AIR SOUTH THROUGH THE PLAINS AND MIDWEST. THIS KEEPS
THE FORECAST AREA IN COOL NORTHWEST FLOW. DAYTIME MIXING PRODUCES
PARTLY CLOUDY SKIES MONDAY AND TUESDAY PLACING A LIMIT ON HEATING.
MONDAY WOULD BE A WINDY DAY WITH NORTHWEST WINDS INCREASING TO 20
TO 30 MPH IN THE AFTN WHICH WEAKEN AT SUNSET. WINDS STAY REASONABLY
STRONG SUNDAY NIGHT ALSO. THE EFFECT ON TEMPERATURES WOULD BE FOR
LOWS MONDAY MORNING FALLING INTO THE UPPER 20S ACROSS WESTERN
NEBRASKA BUT ABOVE FREEZING EAST OF HIGHWAY 83. LOWS FALL BELOW
FREEZING EVERYWHERE MONDAY NIGHT EXCEPT ALONG HIGHWAY 281. HIGHS
RISE INTO THE 50S MONDAY AND LOWER 60S TUESDAY.
THE FORECAST IS DRY AND THE MODELS INDICATE DEW POINTS FALL INTO
TEENS AND 20S SUNDAY NIGHT THROUGH TUESDAY. THE RISK TO THE FORECAST
IS THAT THE VERY DRY AIR COULD SUPPORT COLDER LOWS THAN FORECAST BUT
THAT WOULD COMPETE DIRECTLY WITH THE WARM WET GROUND FROM THE HEAVY
RAINFALL.
EXTENDED RANGE...(TUESDAY NIGHT THROUGH SATURDAY)
A RIDGE IN WESTERN NORTH AMERICA CONTINUES TO BUILD INTO THE
NORTHWEST TERRITORIES AND NORTHERN ALBERTA OPENING UP A PATH FROM
NUNAVUT IN EXTREME NORTHERN CANADA TO NORTH CENTRAL AND NORTHEAST
NEBRASKA. AS A RESULT...TEMPERATURES ARE EXPECTED TO BE A LITTLE
BELOW THE SEASONAL AVERAGES IN THE NORTHEAST NEBRASKA SANDHILLS AND
THE NIOBRARA VALLEY WITH NIGHTTIME TEMPERATURES AT OR BELOW FREEZING
INTO FRIDAY MORNING. EVEN IN THE WESTERN SANDHILLS...THE EASTERN
PANHANDLE AND SOUTHWEST NEBRASKA WILL BE SLIGHTLY BELOW AVERAGE
WITH LOWS IN THE LOW TO MID 30S.
IN THE SOUTHWEST STATES...A TROUGH DIGS INTO SOUTHERN CALIFORNIA
RESULTING IN SOUTHWEST FLOW ALOFT ACROSS THE CENTRAL PLAINS. A WEAK
INVERTED TROUGH MOVING ACROSS THE PLAINS COULD BRING THE POSSIBILITY
OF SHOWERS TO CENTRAL AND WESTERN NEBRASKA THURSDAY THROUGH
SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1228 PM CDT SAT APR 18 2015
LARGE UPPER LEVEL LOW CONTINUES TO MOVE ONLY VERY SLOWLY ACROSS
EASTERN COLORADO. EXPECT ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS TO DEVELOP AS A RESULT THIS AFTERNOON AND TONIGHT.
THE BEST CONCENTRATION OF SHOWERS AND STORMS WILL BE ACROSS
CENTRAL AND SOUTHWEST NEBRASKA...INCLUDING THE KLBF TAF SITE. LATE
TONIGHT A COLD FRONT WILL QUICKLY MOVE SOUTHEAST THROUGH THE
AREA...THIS WILL BRING MVFR AND POSSIBLE IFR CEILINGS WITH IT FROM
AROUND 07Z TO 16Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SPRINGER
SHORT TERM...TAYLOR
MEDIUM RANGE...CDC
EXTENDED RANGE...SPRINGER
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
106 PM CDT SAT APR 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT SAT APR 18 2015
SPC SUGGESTED SIGNIFICANT SEVERE WEATHER POTENTIAL THIS AFTERNOON
AND EARLY THIS EVENING ACROSS PARTS OF SOUTHWEST AND NCNTL NEB. A
PORTION OF THE LOW PRESSURE ACROSS SWRN KS THIS MORNING IS
EXPECTED TO LIFT NORTHEAST THROUGH SCNTL AND ERN NEB THIS
AFTERNOON SETTING UP A UNSTABLE WARM SECTOR FROM ROUGHLY IMPERIAL
TO ONEILL.
ALTHOUGH THE RAP IS FAIRLY QUIET THE NAM AND HRRR SBN MODELS
SUGGEST REASONABLE POTENTIAL FOR CONVECTIVE DEVELOPMENT THIS AFTN
IF SKIES PARTIALLY CLEAR ALLOWING FOR TEMPERATURES TO RISE INTO
THE MID AND UPPER 60S. SATELLITE SHOWS CLEARING THIS MORNING
ACROSS CNTL HIGH PLAINS OF KS/COLO AND IT IS BELIEVED THIS
CLEARING WILL MOVE INTO SCNTL NEB THIS AFTN.
THE STORM ACTIVITY COULD BEGIN AS EARLY AS 18Z IN THE SOUTHWEST
WITH THE NAM SOLN OR AS LATE AS 21Z-00Z IN THE HRRR MODEL.
SATELLITE TIMING TOOLS INDICATE THE CLEARING ACROSS KS COULD
REACH SOUTHWEST NEB BY 13-15Z THIS MORNING WHICH WOULD PROVIDE A
GOOD START FOR MODEST HEATING GIVEN THAT THIS CLEARING AREA WOULD
TEND TO FILL IN WITH DEVELOPING CUMULUS.
ONE WEAKNESS ARE THE WIND FIELDS 500MB AND BELOW WHICH ARE LIGHT
PRODUCING BULK SHEAR VALUES OF 30KT OR LESS WHICH MIGHT SUPPORT
MORE OF HEAVY RAIN THREAT. STILL TEMPERATURES ALOFT WILL BE VERY
COLD AS THE H500MB LOW ACROSS COLO MOVES EAST TO NEAR
LIMON/SPRINGFIELD. WINDS AT 300MB ARE STRONG NEAR 65KT
POTENTIALLY ENHANCING UPDRAFTS AND PROVIDING VENTILATION.
FREEZING LEVELS ARE NEAR 5KFT SUPPORTING A LOW TOP STORM
ENVIRONMENT AND GOOD POTENTIAL FOR HAIL. THE NAM IS PRODUCING
AROUND 2000 J/KG OF CAPE AT NORTH PLATTE AND BROKEN BOW WHILE THE
RAP AND OTHER MODELS SHOW HALF OR LESS THAT VALUE.
NORTHWEST WINDS WILL SWEEP IN FROM THE WEST IN THE WAKE OF THE
DISTURBANCE TONIGHT. THIS SHOULD PRODUCE DRYING AND DECREASING
RAIN CHANCES FROM MIDNIGHT ONWARD.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 328 AM CDT SAT APR 18 2015
SUNDAY WILL SEE THE STRONG LOW PRESSURE WEAKENING AS IT PUSHES
EAST WHILE A TROUGH DIGS ACROSS THE CANADIAN PLAINS. SOME
LINGERING SUNDAY MORNING SHOWERS ARE POSSIBLE IN THE EASTERN
ZONES...HOWEVER THE BIGGER EVENTS OF THE DAY WILL BE THE CAA AND
INCREASING NW WINDS. AS THE LOW PUSHES ACROSS KS...DRY AIR WILL
QUICKLY FILL IN BEHIND...RESULTING IN DECREASING CLOUDS FROM WEST
TO EAST IN THE MORNING. BY AFTERNOON SHOULD SEE MOSTLY SUNNY
SKIES FOR ALL. THE SUN WILL COMBINE WITH THE STRONG NW WINDS
/GUSTING TO 30 TO 40 MPH/ TO PROMOTE GOOD MIXING OF THE BL AND
OFFSET THE CAA AND TEMPS PUSH INTO THE 50S.
EARLY IN THE WEEK THE TROUGH DIGS TOWARDS THE GREAT LAKES REGION
AND ABSORBS THE SOUTHERN LOW. ELONGATED SFC HIGH PRESSURE BUILDS
ACROSS THE HIGH PLAINS. THE ACTIVE WEATHER IS WELL TO THE NE
ALTHOUGH A FEW UPPER LEVEL DISTURBANCES WILL RIDE ALONG THE NW
FLOW OVERHEAD AND BRING SOME PASSING CLOUDS AT TIMES. LIMITED
MOISTURE IN THE LOWER LEVELS AND MODELS/FORECAST ARE DRY. TEMPS
TO START THE WEEK WILL BE CHILLY IN THE MORNING WITH MOST AREAS
NEAR OR BELOW THE FREEZING MARK. STILL A COUPLE OF WEEKS FROM
TYPICAL LAST FREEZE FOR MOST OF THE AREA...SO NO HEADLINES NEEDED
YET. HIGHS REBOUND NICELY WITH A WARMING TREND WITH 60S MAYBE 70
FOR WED AND THURS.
EYES THEN FOCUS ON A TROUGH AS IT DIGS ACROSS THE SOUTHWEST.
MODELS IN GOOD AGREEMENT DEVELOPING A CLOSED 500 MB LOW NEAR SRN
CAL BY THURS. THE LOW THEN LIFTS TOWARDS THE 4 CORNERS WHILE
BECOMING AN OPEN WAVE. THE WAVE WILL THEN PUSH ACROSS THE PLAINS
TO END THE WEEK. THIS WILL BRING A RETURN OF THE ACTIVE
WEATHER...AND WILL HAVE POPS TOWARDS THE END OF THE EXTENDED
PERIOD. STILL HAVE SOME LOCATION AND TIMING ISSUES TO IRON OUT
WHICH IS TYPICAL THIS FAR OUT SO POPS KEPT BELOW 50 PERCENT FOR
NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1228 PM CDT SAT APR 18 2015
LARGE UPPER LEVEL LOW CONTINUES TO MOVE ONLY VERY SLOWLY ACROSS
EASTERN COLORADO. EXPECT ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS TO DEVELOP AS A RESULT THIS AFTERNOON AND TONIGHT.
THE BEST CONCENTRATION OF SHOWERS AND STORMS WILL BE ACROSS
CENTRAL AND SOUTHWEST NEBRASKA...INCLUDING THE KLBF TAF SITE. LATE
TONIGHT A COLD FRONT WILL QUICKLY MOVE SOUTHEAST THROUGH THE
AREA...THIS WILL BRING MVFR AND POSSIBLE IFR CEILINGS WITH IT FROM
AROUND 07Z TO 16Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
314 PM CDT SAT APR 18 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 315 PM CDT SAT APR 18 2015
RAINFALL POTENTIAL THROUGH TONIGHT HIGHLIGHTS THE SHORT TERM
FORECAST.
AS OF 1930 UTC...A COLD FRONT WAS JUST ENTERING NORTHWEST NORTH
DAKOTA AND WILL CONTINUE TO PROPAGATE THROUGH CENTRAL NORTH DAKOTA
THIS EVENING. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WITH
WEAK INSTABILITY HAVE DEVELOPED ALONG THIS FRONT AND WILL APPROACH
THE HIGHWAY 83 CORRIDOR BY 01-02 UTC. AS CYCLOGENESIS OCCURS
ACROSS EASTERN SOUTH DAKOTA THROUGH THE NIGHT AND THE NORTHERN STREAM
WAVE ASSOCIATED WITH THE COLD FRONT PHASES WITH THE LOW TO THE
SOUTH...RAINFALL COVERAGE WILL INCREASE ACROSS CENTRAL NORTH
DAKOTA THROUGH THE EVENING AND NIGHT. THEREAFTER...A WINDY SUNDAY
IS FORECAST IN THE WAKE OF THE NOW DEEPENING LOW ACROSS MINNESOTA.
AT THIS TIME...WIND GUSTS APPEAR TO STAY BELOW ADVISORY CRITERIA
WITH 30 TO 35 KTS TO MIX IN COLD AIR ADVECTION. SCATTERED LIGHT
RAIN SHOWERS ARE ALSO EXPECTED IN WRAP AROUND MOISTURE WITH
PERHAPS A FEW SNOWFLAKES MIXING IN SUNDAY MORNING AS TEMPERATURES
FALL INTO THE MID 30S NORTHWEST AND NORTH CENTRAL. GIVEN GOOD
AGREEMENT...WILL WEIGH HEAVILY ON THE 16-18 UTC HRRR ITERATIONS
BLENDED TO THE GLOBAL 12 UTC DETERMINISTIC AND ENSEMBLE SUITE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 PM CDT SAT APR 18 2015
WINDY WITH SCATTERED SHOWERS TO BEGIN THE EXTENDED...COOL AND DRY
THROUGH THE REMAINDER OF THE WEEK.
AS THE MAIN SURFACE LOW ENTERS NORTHERN MINNESOTA AND SOUTHERN
CANADA...MOISTURE SHOULD WRAP AROUND THE BACKSIDE...PROVIDING
NORTH DAKOTA WITH SOME SCATTERED LIGHT RAIN. THE HIGH RESOLUTION
SHORT TERM MODELS ARE A LITTLE MORE ROBUST WITH PRECIPITATION
COVERAGE THAN THE GLOBAL MODELS (ECMWF/GFS). WITH THE LOW
REMAINING NEARBY AND REMAINING UNDER THE INFLUENCE OF A FAVORABLE
JET STREAK...LIGHT SHOWERS HERE AND THERE AREN`T OUT OF THE
QUESTION THROUGH TUESDAY. GUSTY WINDS ARE EXPECTED THOUGH THE DAY
SUNDAY AND MONDAY AS THE PRESSURE GRADIENT TIGHTENS WITH THE
SURFACE LOW DEEPENING AND PROPAGATING TOWARD THE GREAT LAKES.
THESE GUSTY NORTHWEST WINDS WILL BE ADVECTING DRIER AIR INTO THE
AREA. THIS COULD CREATE RATHER CRITICAL FIRE CONDITIONS MONDAY AS
RELATIVE HUMIDITY DROPS BELOW 20 PERCENT.
THROUGH THE REMAINDER OF THE WORK WEEK...UPPER LOW SLOWLY WORKS
OFF TO THE EAST KEEPING NORTH/NORTHWESTERLY FLOW OVER OUR AREA.
WITH THE EXCEPTION OF ISOLATED SHOWERS EARLY THIS WEEK...DRY
WEATHER IS EXPECTED. TEMPERATURES WILL REMAIN A BIT BELOW
AVERAGE WITH READINGS IN THE 50S FOR HIGHS AND 20S/30S FOR LOWS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 315 PM CDT SAT APR 18 2015
A COLD FRONT ACROSS WESTERN NORTH DAKOTA THIS AFTERNOON WILL
MOVE ACROSS THE CENTRAL THIS EVENING AND MERGE WITH A LOW
DEVELOPING ACROSS EASTERN SOUTH DAKOTA TONIGHT. SCATTERED RAIN
SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS WESTERN
NORTH DAKOTA THIS AFTERNOON...WITH MORE WIDESPREAD RAIN SHOWERS
POSSIBLE AT KMOT/KBIS/KJMS THIS EVENING AND TONIGHT. EMBEDDED MVFR
CONDITIONS POSSIBLE IN RAIN.
&&
.FIRE WEATHER...
ISSUED AT 315 PM CDT SAT APR 18 2015
CRITICAL FIRE WEATHER CONDITIONS MAY BE POSSIBLE ON MONDAY...AND
THIS WILL NEED TO BE MONITORED. WHILE TEMPERATURES WILL ONLY BE IN
THE 50S...MINIMUM RELATIVE HUMIDITY LEVELS OF 15 TO 20 PERCENT AND
NORTHWEST WINDS OF 25 TO 35 MPH ARE POSSIBLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...AJ
AVIATION...AYD
FIRE WEATHER...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1230 PM CDT SAT APR 18 2015
.UPDATE...
ISSUED AT 1230 PM CDT SAT APR 18 2015
NO SIGNIFICANT CHANGES WITH THIS UPDATE AS THE 12 UTC
DETERMINISTIC SUITE AND 13-16 UTC HRRR ITERATIONS MATCH WELL TO
OBSERVED TRENDS THROUGH 17 UTC OF RAIN SLOWLY PROPAGATING NORTH
FROM SOUTH DAKOTA IN ASSOCIATION WITH THE UPPER LEVEL LOW AND
RAIN SHOWER ACTIVITY JUST BEGINNING ACROSS EASTERN MONTANA
ALONG THE COLD FRONT.
UPDATE ISSUED AT 920 AM CDT SAT APR 18 2015
WILL CONTINUE TO FAVOR THE TRENDS OF THE 10-13 UTC HRRR ITERATIONS
WHICH KEEP THE BAND OF PRECIPITATION ACROSS SOUTHERN SOUTH DAKOTA
AND EASTERN NEBRASKA IN ASSOCIATION WITH THE UPPER LEVEL LOW FOR
THE MOST PART TO THE SOUTH OF NORTH DAKOTA UNTIL 22-24 UTC THIS
EVENING GIVEN DRY EAST-SOUTHEASTERLY LOW LEVEL FLOW PRECEDING
THIS SYSTEM. BETTER CHANCES FOR SHOWER ACTIVITY THIS AFTERNOON ARE
ACROSS THE WEST AS A COLD FRONT ACROSS EASTERN MONTANA THIS
MORNING ENTERS WESTERN NORTH DAKOTA THIS AFTERNOON. DID ADD A
MENTION OF THUNDERSTORMS TO THE WEST ALONG THE FRONT WITH SOME
WEAK INSTABILITY DEPICTED ON THE 06 UTC NAM/GFS BUFR SOUNDINGS.
UPDATE ISSUED AT 626 AM CDT SAT APR 18 2015
A FEW WEAK RADAR ECHOS ARE TRYING TO SNEAK INTO THE SOUTH CENTRAL
PART OF THE STATE...THOUGH THESE APPEAR WEAK AND DOUBTFUL MORE THAN
A FEW SPRINKLES COULD BE HITTING THE GROUND. WITH THAT SAID...LATEST
GUIDANCE IS STILL ON TRACK FOR SHOWERS TO BE ON THE INCREASE LATE
DAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 424 AM CDT SAT APR 18 2015
MARGINAL FIRE WEATHER CONDITIONS AND CHANCES FOR MUCH NEEDED
RAIN WILL HIGHLIGHT THE SHORT TERM.
AS TWO UPPER LEVEL LOWS CONVERGE OVER THE NORTHERN PLAINS THROUGH
SATURDAY...MOISTURE TRANSPORT FROM THE SOUTH AND ATMOSPHERIC
INSTABILITY WILL CREATE WIDESPREAD CHANCES FOR RAIN. SOUTHERN AND
EASTERN AREAS OF THE STATE ARE EXPECTED TO HAVE THE GREATEST CHANCES
FOR SUBSTANTIAL RAIN...CONCLUDED THROUGH GOOD AGREEMENT WITH THE
CURRENT 00Z MODEL SUITE. CHANCES FOR RAIN ARE FORECAST TO INITIATE
THROUGH SATURDAY AFTERNOON AND PERSIST INTO SUNDAY MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 424 AM CDT SAT APR 18 2015
ON SUNDAY...DEEPENING TROUGH CLOSES OFF OVER MANITOBA WHILE LOW OVER
THE SOUTHERN PLAINS WASHES INTO THE NORTHERN SYSTEM. PRECIPITATION
CHANCES WILL CONTINUE PRIMARILY OVER CENTRAL AND NORTHERN NORTH
DAKOTA...THOUGH MOISTURE WRAPPING AROUND THE BACK SIDE OF THE SYSTEM
WILL STILL KEEP LOWER PRECIPITATION CHANCES FURTHER SOUTH AND WEST.
GUSTY WINDS EXPECTED THOUGH THE DAY IN TIGHT PRESSURE GRADIENT WITH
SURFACE LOW PUSHING INTO THE MIDWEST. WINDS WILL REMAIN BREEZY
OVERNIGHT WITH LOW RAIN/SNOW CHANCES LINGERING OVER CENTRAL NORTH
DAKOTA.
UPPER LOW PUSHES ALONG THE MINNESOTA/ONTARIO BORDER ON MONDAY. THIS
WILL KEEP LOW PRECIPITATION CHANCES GOING PRIMARILY OVER THE JAMES
RIVER VALLEY. WITH TIGHT PRESSURE GRADIENT ON THE BACK SIDE OF THIS
SYSTEM...WILL KEEP THE STRONGER WINDS MAINLY OVER CENTRAL NORTH
DAKOTA...DECREASING TOWARDS THE WEST.
THROUGH THE REMAINDER OF THE WORK WEEK...UPPER LOW SLOWLY WORKS OFF
TO THE EAST KEEPING NORTH/NORTHWESTERLY FLOW OVER OUR AREA. WITH THE
EXCEPTION OF A FEW SHOWERS POSSIBLE ON TUESDAY AS A FAST MOVING WAVE
SLIDES THROUGH THE FLOW...DRY WEATHER IS EXPECTED. TEMPERATURES WILL
REMAIN A BIT BELOW AVERAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1225 PM CDT SAT APR 18 2015
A COLD FRONT ACROSS EASTERN MONTANA THIS MORNING WILL ENTER
WESTERN NORTH DAKOTA THIS AFTERNOON AND MERGE WITH A LOW
DEVELOPING ACROSS EASTERN SOUTH DAKOTA TONIGHT. SCATTERED RAIN
SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS WESTERN
NORTH DAKOTA THIS AFTERNOON...WITH MORE WIDESPREAD RAIN SHOWERS
POSSIBLE AT KMOT/KBIS/KJMS THIS EVENING AND TONIGHT. EMBEDDED MVFR
CONDITIONS POSSIBLE IN RAIN.
&&
.FIRE WEATHER...
ISSUED AT 424 AM CDT SAT APR 18 2015
RELATIVE HUMIDITY VALUES ARE PROJECTED TO BE IN THE LOWER TO MID
20S THIS AFTERNOON OVER CENTRAL NORTH DAKOTA. WITH SOUTHERLY WINDS
OF AROUND 10 TO 20 MPH...NEAR CRITICAL FIRE WEATHER CONDITIONS
WILL BE POSSIBLE. OVER WESTERN NORTH DAKOTA...A COLD FRONT WILL
PUSH INTO THE AREA BRINGING A WIND SHIFT TO THE NORTHWEST. BEHIND
THE FRONT...WINDS WILL INCREASE TO AROUND 25 MPH. RELATIVE
HUMIDITY VALUES WILL BE HIGHER OVER THIS REGION...INCREASING
BEHIND THE FRONT...THOUGH THIS STILL MAY BRING A PERIOD OF NEAR
CRITICAL FIRE WEATHER CONDITIONS. WETTING RAINS POSSIBLE
TONIGHT...ESPECIALLY OVER THE EASTERN HALF OF THE STATE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...AC
LONG TERM...JJS
AVIATION...AYD
FIRE WEATHER...AC/JJS
AREA FORECAST DISCUSSION
NWS NORMAN OK6
1150 AM CDT SAT APR 18 2015
.AVIATION...
EXPECT VFR CEILINGS THROUGH THE AFTN WITH A ROUND OF
TSTMS TO AFFECT MOST TAF SITES LATE THIS AFTN INTO THIS EVENING. A
COLD FRONT WILL BRING A WIND SHIFT FROM NW TO SE OVERNIGHT INTO
SUNDAY MORNING. SOME GUSTS TO NEAR 30KTS POSSIBLE IN NORTHWEST OK.
30
&&
.PREV DISCUSSION... /ISSUED 646 AM CDT SAT APR 18 2015/
.DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
&&
.AVIATION...
HAVE LOW CONFIDENCE OF VFR TO LIFR CONDITIONS IN WESTERN OKLAHOMA
THROUGH 21Z AS WELL AS LOW CONFIDENCE WITH TSRA TIMING/COVERAGE
AFTER 19Z.
CONDITIONS WILL BOUNCE BETWEEN VFR AND LIFR WITH BR/FG ACROSS
WESTERN OKLAHOMA THROUGH 21Z. THE WORST CONDITIONS MAY BE NEAR
KCSM AND KHBR THROUGH 15Z. IFR CONDITIONS MAY AFFECT KSPS AND KLAW
AS WELL THROUGH 15Z...BUT DID NOT MENTION THINKING THESE LOWER
CONDITIONS WILL STAY WEST OF THESE SITES.
HAVE HIGH CONFIDENCE ALL SITES WILL BE VFR BY 21Z.
ISO-NUM TSRA WILL FORM AND AFFECT MANY TAF SITES AFTER 19Z. USED
VCTS/TEMPOS AT MOST SITES EXCEPT KCSM AND KHBR WHERE CONFIDENCE OF
STORMS IS TOO LOW TO MENTION. BRIEF VARIABLE GUSTY WINDS...
HAIL...AND MVFR OR LOWER CONDITIONS ARE POSSIBLE WITH THE
STRONGEST STORMS. MOST STORMS WILL BE EAST OF ALL TAF SITES BY
04Z.
ADDITIONAL MVFR/IFR CONDITIONS MAY DEVELOP AFTER 06Z BUT DID NOT
MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE.
MBS
&&
.PREV DISCUSSION... /ISSUED 419 AM CDT SAT APR 18 2015/
DISCUSSION...
SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON AND EVENING IS THE
MAIN CONCERN.
RAIN CHANCES THIS MORNING LOOK TO BE MAINLY CONFINED TO LOCATIONS
EAST OF I-35 WHERE MOST LATEST RADAR ECHOES WERE OCCURRING FROM A
WEAK IMPULSE ROTATING AROUND A MID/UPPER LOW IN SOUTHERN
COLORADO. NO SEVERE STORMS ARE EXPECTED WITH THIS ACTIVITY...JUST
SOME LOCALIZED HEAVY RAIN. MOST OF THIS ACTIVITY MAY END BY 8 AM
IF THE LATEST HRRR RUNS ARE CORRECT. MOST LOCATIONS WILL REMAIN
DRY THIS MORNING.
ADDED PATCHY FOG MENTION THROUGH 11 AM THIS MORNING ACROSS PARTS
OF WESTERN OKLAHOMA AND WESTERN NORTH TEXAS WHERE SOME PARTIAL
CLEARING...ABUNDANT LOW LEVEL MOISTURE...AND LATEST HRRR RUNS
FAVOR SOME DEVELOPMENT. DOUBT IT WILL GET TOO WIDESPREAD OR DENSE.
THIS AFTERNOON AND EVENING...ISOLATED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL DEVELOP ACROSS THE AREA. CAPPING WILL BE RATHER
WEAK. WITH MORE SUN COMPARED TO YESTERDAY...THINK CONVECTIVE
TEMPERATURES WILL BE REACHED RATHER EASILY IN THE 2 TO 5 PM TIME
FRAME. FIRST DEVELOPMENT MAY BE FOCUSED IN WESTERN OKLAHOMA AND
WESTERN NORTH TEXAS NEAR A DEVELOPING DRYLINE. WENT NEAR GUIDANCE
RAIN CHANCES. EXACTLY WHERE AND WHEN STORMS OCCUR REMAINS TRICKY
TODAY AND TONIGHT.
IN REGARDS TO SEVERE POTENTIAL THIS AFTERNOON AND EVENING...
BELIEVE THERE WILL BE SOME SEVERE STORMS WITH LARGE HAIL AS THE
MAIN CONCERN. THE AIR WILL BE MODERATELY UNSTABLE WITH MLCAPE
1500-2500 J/KG. STRONG 0-6 KM SHEAR 30-50 KT SUPPORTS SUPERCELLS
AND MULTICELLS. STRONG 0-3 KM SHEAR VALUES 25-45 KT AND VERY COLD
MID LEVELS WITH 500 MB TEMPERATURES AROUND -18C COULD SUPPORT VERY
LARGE HAIL IN SOME CELLS AS LONG AS CONVECTION IS NOT TOO
WIDESPREAD. SOME DAMAGING WINDS MAY OCCUR AS WELL IF STORMS CAN
ORGANIZE INTO CLUSTERS AND LINES. TORNADO POTENTIAL APPEARS TO BE
LIMITED DUE TO WEAK LOW LEVEL SHEAR...THOUGH NOTICED THE LATEST
RAP13 INDICATED STRONGER LOW LEVEL WINDS POSSIBLY DEVELOPING IN
SOUTHWESTERN OKLAHOMA IN THE 5 TO 9 PM TIME FRAME WHICH MAY
INCREASE THIS POTENTIAL. WILL CLOSELY MONITOR.
LOCALLY HEAVY RAINFALL MAY AGAIN OCCUR LATE THIS AFTERNOON AND
TONIGHT...THOUGH STORM MOTIONS WILL BE FASTER WHICH MAY LIMIT THE
DURATION OF HEAVY RAINFALL IN ONE GIVEN LOCATION.
MOST STORMS WILL MOVE INTO EASTERN OKLAHOMA AFTER MIDNIGHT
TONIGHT...ALLOWING FOR MOIST AND COOL CONDITIONS. WOULD NOT BE
SURPRISED IF SOME FOG FORMED...BUT DID NOT MENTION DUE TO LOW
CONFIDENCE.
ON SUNDAY...A FEW SHOWERS AND STORMS MAY LINGER MAINLY OVER
NORTHERN OKLAHOMA...THOUGH APPEARS THE SEVERE POTENTIAL WILL SHIFT
IN FAR EASTERN OKLAHOMA AND POINTS EAST. WITH LINGERING WEAK
INSTABILITY AND COLD MID/UPPER LEVELS...A FEW STORMS WITH SMALL
HAIL COULD OCCUR. BREEZY CONDITIONS WILL DEVELOP. THERE IS AN
OUTSIDE CHANCE WINDS COULD APPROACH ADVISORY CRITERIA WITH GUSTS
OVER 40 MPH IN NORTHWEST OKLAHOMA. WENT WITH THE WARMER SIDE OF
GUIDANCE TEMPERATURES THINKING SOME SUN WILL OCCUR...ESPECIALLY
EARLY IN THE DAY.
SUNDAY NIGHT THROUGH FRIDAY...A WET PATTERN MAY CONTINUE WITH
RAIN CHANCES REMAINING IN THE FORECAST MOST DAYS. THERE ARE SOME
MODEL DISCREPANCIES WITH WEATHER FEATURES...THUS FORECAST
CONFIDENCE REMAINS LOW. SOME STRONG TO SEVERE STORMS MAY OCCUR
TUESDAY THROUGH FRIDAY WITH NEARBY MOISTURE AND INSTABILITY.
MBS
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
25/17/17
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1243 PM CDT SAT APR 18 2015
.UPDATE...
ISSUED AT 1030 AM CDT SAT APR 18 2015
WITH DRY AIR IN PLACE...ERODING NORTHERN EXTENT OF SHOWER
ACTIVITY...REDUCED POPS/QPF NORTH OF THE MAIN BAND OF
PRECIPITATION FOR THE AFTERNOON IN LINE WITH LATEST HRRR AND RUC
GUIDANCE. LATEST NAM IS IN LINE WITH CURRENT FORECAST AFTER 00Z.
HRRR COLUMN MAX REF DOES LOOK LIKE A WEAK FEW CONVECTIVE CELLS
FORM OVER THE CWA TODAY SO WILL LEAVE MENTION OF THUNDER IN.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 327 AM CDT SAT APR 18 2015
PRECIPITATION CHANCES OVER THE NEXT 24 HOURS...AND WINDS SUNDAY
AND MONDAY WILL BE THE FORECAST CHALLENGES.
A FAIRLY DRY AIR MASS REMAINS IN PLACE ACROSS MOST OF THE CWA THIS
MORNING WITH DEW POINTS MAINLY IN THE UPPER 20S. HIGHER DEW
POINTS ARE ADVECTING NORTHWESTWARD INTO WESTERN SOUTH DAKOTA WHERE
VALUES IN THE 40S. THESE HIGHER DEW POINTS...ALONG WITH SOME
SHOWERS AND THUNDERSTORMS WILL SLOWLY TRACK NORTHWARD THROUGH THE
DAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES ACROSS THE CENTRAL
PLAINS. VARIOUS HI-RES MODELS SUGGEST SHOWERS WOULD REACH HIGHWAY
212 AROUND 18Z...AND HIGHWAY 12 BETWEEN 21-0Z THIS AFTERNOON. HAVE
TRIED TO DELAY POPS IN THE NORTHERN AND FAR NORTHEASTERN PORTION
OF THE CWA UNTIL AFTER 21Z. PCPN MAY NOT REACH THE
SISSETON/WHEATON AREA UNTIL AFTER 0Z SUNDAY.
TONIGHT THROUGH SUNDAY MORNING...MODELS SUGGEST THE LOW PRESSURE
SYSTEM WILL MERGE WITH A NORTHERN STREAM TROUGH...WHICH COULD
BRING BETTER CHANCES FOR SHOWERS. THE NORTHERN STREAM WILL LIKELY
BRING GUSTY NORTHWESTERLY WINDS TONIGHT ALONG A SURFACE COLD
FRONT. A FAIRLY DRY AIR MASS WILL FOLLOW THIS COLD FRONT WITH PCPN
LIKELY ENDING FROM WEST TO EAST BY THE MID MORNING HOURS ON
SUNDAY. BY SUNDAY AFTERNOON COLD AIR ADVECTION WILL DEVELOP WITH
GUSTY NORTHWESTERLY WINDS AND INSTABILITY SHOWERS POSSIBLE. WINDS
MAY EXCEED ADVISORY LEVELS...ESPECIALLY IN THE WESTERN HALF OF THE
CWA. A TIGHT PRESSURE GRADIENT OVER THE REGION WILL PROMOTE GUSTY
NORTHWESTERLY WINDS ON MONDAY AS WELL. COLD AIR ALOFT...ALONG WITH
CAPE VALUES AROUND 100 J/KG COULD PRODUCE ISOLATED SHOWERS IN THE
FAR EASTERN PORTION OF THE CWA MONDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 327 AM CDT SAT APR 18 2015
NOT MUCH CHANGE NOTED IN THE LONGER RANGE MODEL OUTPUT...COMPARED
TO 24 HOURS. PRECIPITATION CHANCES ARE PRETTY MUCH DONE AND GONE
MONDAY NIGHT...WITH A MAINLY DRY FORECAST THERE-AFTER /DRY AND
COOL NORTHWEST FLOW ESTABLISHING OVER THE NORTHERN PLAINS ALOFT/.
BY THURSDAY...THERE IS A RATHER SLIM CHANCE THAT ENERGY TRYING
TO LIFT NORTH-NORTHEAST TOWARD THE NORTHERN PLAINS COULD INTRODUCE
SOME DEFORMATION ZONE-FORCED LIGHT PRECIP POTENTIAL ACROSS THE
SOUTHWESTERN FORECAST ZONES...PRIOR TO EXPERIENCING THE SHEARING
EFFECTS OF NORTHWEST /POLAR JET/ FLOW ALOFT. SUPERBLEND CONTINUES
TO PRODUCE SOME LOW PROBABILITIES FOR PRECIPITATION THURSDAY
NIGHT/FRIDAY THOUGH. UNDER THIS NORTHWEST FLOW ALOFT REGIME...LOW
LEVEL FLOW IS PERSISTENTLY ADVECTING COOL/DRY AIR DOWN OUT OF
CANADA ON NORTHEASTERLY BOUNDARY LAYER MIXING WINDS. TEMPERATURES
DURING THE EXTENDED FORECAST PERIOD SHOULD BE RUNNING NEAR NORMAL
TO PERHAPS A FEW DEGREES BELOW NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1236 PM CDT SAT APR 18 2015
A LOW PRESSURE SYSTEM WILL BRING SOME SHOWERS TO THE REGION THIS
AFTERNOON AND EVENING. VFR CONDITIONS ARE EXPECTED THROUGH THE
PERIOD EXCEPT PERHAPS SOME BRIEF AND TRANSIENT MVFR CIGS IN HEAVIER
SHOWERS NEAR KMBG/KATY THIS EVENING. AS THE LOW EXITS SHOWERS WILL
TAPER OFF BY 9Z AND NORTHWEST WINDS WILL INCREASE TO 15 TO 25 KTS
WITH HIGHER GUSTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...SD
LONG TERM...DORN
AVIATION...WISE
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
530 PM CDT SAT APR 18 2015
.UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT CURRENT REGIONAL
SFC OBS...SATELLITE...AND MOSAIC RADAR TRENDS ALONG WITH THE LATEST IN
SHORT RANGE MODEL CONSENSUS...THUS MAINTAINING ISO SHWRS/TSTMS THRU AT
LEAST THE MID EVENING HRS. BULK OF SHWR/TSTMS ACTIVITY SHOULD SPREAD FROM
THE SW TO THE NE ACROSS THE MID STATE AFTER MIDNIGHT.
&&
.PREV DISCUSSION.../ISSUED 351 PM CDT SAT APR 18 2015/
DISCUSSION...
AS AN UPPER TROUGH CENTERED OVER THE CENTRAL PLAINS MOVES EAST THIS
AFTERNOON AND OVERNIGHT IT WILL INFLUENCE SHOWERS AND THUNDERSTORMS
TO CONTINUE THEIR TREK NORTHWARD THROUGH MIDDLE TN. HRRR IS FORECASTING
SCATTERED AFTERNOON ACTIVITY TO MOVE INTO KENTUCKY AND ANOTHER
WAVE OF PRECIP TO SPREAD INTO MIDDLE TENNESSEE FROM THE SOUTH
BEFORE MIDNIGHT. PWAT VALUES WILL BE AROUND 1.5 INCHES FOR SEVERAL
HOURS OVERNIGHT TONIGHT. WITH THE GROUND ALREADY SATURATED FROM
THIS PAST WEEK`S RAINFALL...WE COULD SEE CREEKS AND STREAMS RISE
PRETTY QUICKLY DURING THE OVERNIGHT HOURS...WATCH FOR MINOR
FLOODING IN LOW LYING AREAS AND PONDING OF WATER ON ROADWAYS
OVERNIGHT. WHILE THERE MAY BE STORMS AROUND...NOT EXPECTING
ANYTHING STRONG OR SEVERE TONIGHT.
BETWEEN LATE SUNDAY MORNING AND EARLY AFTERNOON THE DEEPEST
MOISTURE WILL PUSH NORTH OF OUR AREA. LINGERING CLOUD
COVER...ESPECIALLY OVER THE NORTHEASTERN PORTION OF THE CWA MAY
INHIBIT INSTABILITY...BUT CLOUDS SHOULD BREAK UP ENOUGH DURING
THE AFTERNOON HOURS TO ALLOW FOR TEMPERATURES TO WARM INTO THE LOW
70S ALONG THE CUMBERLAND PLATEAU AND MID 70S ELSEWHERE. THIS
SHOULD BE WARM ENOUGH TO INITIATE ISOLATED TO SCATTERED STORMS
THROUGHOUT THE AFTERNOON. CURRENTLY SPC HAS THE MID-STATE IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS FOR SUNDAY AFTERNOON THROUGH
SUNDAY NIGHT. THE MAIN THREAT WITH ANY STORMS DURING THIS TIME
FRAME WILL BE DAMAGING WINDS AND HAIL. WE COULD SEE A COUPLE OF
ROUNDS OF THUNDERSTORMS OVERNIGHT SUNDAY NIGHT AHEAD OF A
SHORTWAVE AND ITS ASSOCIATED SURFACE LOW...WHICH STRENGTHEN OVER
SOUTHERN ILLINOIS AND HEAD NORTHEAST ON MONDAY.
THE FRONTAL PASSAGE ASSOCIATED WITH THE AFOREMENTIONED LOW WILL
OCCUR ON MONDAY AND WILL ALLOW FOR TEMPERATURES TO COOL INTO THE
40S OVERNIGHT MONDAY NIGHT. ALL PRECIP SHOULD PUSH EAST OF THE
TENNESSEE VALLEY TUESDAY NIGHT. A SURFACE HIGH MOVES IN ON TUESDAY
AND GIVES US A MUCH NEEDED DRY AND RELATIVELY COOL DAY WITH HIGH
TEMPERATURES IN THE MID 60S.
THE NEXT CHANCE OF PRECIP ENTERS THE FORECAST WEDNESDAY EVENING AS
A WEAK FRONT BRINGS A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH
THE AREA. COULD SEE A BREAK ON FRIDAY AS THAT MOISTURE PUSHES
SOUTH...THEN ANOTHER SURFACE LOW BRINGS ADDITIONAL THUNDERSTORM
CHANCES FRIDAY NIGHT.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
351 PM CDT SAT APR 18 2015
.DISCUSSION...
AS AN UPPER TROUGH CENTERED OVER THE CENTRAL PLAINS MOVES EAST THIS
AFTERNOON AND OVERNIGHT IT WILL INFLUENCE SHOWERS AND THUNDERSTORMS
TO CONTINUE THEIR TREK NORTHWARD THROUGH MIDDLE TN. HRRR IS FORECASTING
SCATTERED AFTERNOON ACTIVITY TO MOVE INTO KENTUCKY AND ANOTHER
WAVE OF PRECIP TO SPREAD INTO MIDDLE TENNESSEE FROM THE SOUTH
BEFORE MIDNIGHT. PWAT VALUES WILL BE AROUND 1.5 INCHES FOR SEVERAL
HOURS OVERNIGHT TONIGHT. WITH THE GROUND ALREADY SATURATED FROM
THIS PAST WEEK`S RAINFALL...WE COULD SEE CREEKS AND STREAMS RISE
PRETTY QUICKLY DURING THE OVERNIGHT HOURS...WATCH FOR MINOR
FLOODING IN LOW LYING AREAS AND PONDING OF WATER ON ROADWAYS
OVERNIGHT. WHILE THERE MAY BE STORMS AROUND...NOT EXPECTING
ANYTHING STRONG OR SEVERE TONIGHT.
BETWEEN LATE SUNDAY MORNING AND EARLY AFTERNOON THE DEEPEST
MOISTURE WILL PUSH NORTH OF OUR AREA. LINGERING CLOUD
COVER...ESPECIALLY OVER THE NORTHEASTERN PORTION OF THE CWA MAY
INHIBIT INSTABILITY...BUT CLOUDS SHOULD BREAK UP ENOUGH DURING
THE AFTERNOON HOURS TO ALLOW FOR TEMPERATURES TO WARM INTO THE LOW
70S ALONG THE CUMBERLAND PLATEAU AND MID 70S ELSEWHERE. THIS
SHOULD BE WARM ENOUGH TO INITIATE ISOLATED TO SCATTERED STORMS
THROUGHOUT THE AFTERNOON. CURRENTLY SPC HAS THE MID-STATE IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS FOR SUNDAY AFTERNOON THROUGH
SUNDAY NIGHT. THE MAIN THREAT WITH ANY STORMS DURING THIS TIME
FRAME WILL BE DAMAGING WINDS AND HAIL. WE COULD SEE A COUPLE OF
ROUNDS OF THUNDERSTORMS OVERNIGHT SUNDAY NIGHT AHEAD OF A
SHORTWAVE AND ITS ASSOCIATED SURFACE LOW...WHICH STRENGTHEN OVER
SOUTHERN ILLINOIS AND HEAD NORTHEAST ON MONDAY.
THE FRONTAL PASSAGE ASSOCIATED WITH THE AFOREMENTIONED LOW WILL
OCCUR ON MONDAY AND WILL ALLOW FOR TEMPERATURES TO COOL INTO THE
40S OVERNIGHT MONDAY NIGHT. ALL PRECIP SHOULD PUSH EAST OF THE
TENNESSEE VALLEY TUESDAY NIGHT. A SURFACE HIGH MOVES IN ON TUESDAY
AND GIVES US A MUCH NEEDED DRY AND RELATIVELY COOL DAY WITH HIGH
TEMPERATURES IN THE MID 60S.
THE NEXT CHANCE OF PRECIP ENTERS THE FORECAST WEDNESDAY EVENING AS
A WEAK FRONT BRINGS A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH
THE AREA. COULD SEE A BREAK ON FRIDAY AS THAT MOISTURE PUSHES
SOUTH...THEN ANOTHER SURFACE LOW BRINGS ADDITIONAL THUNDERSTORM
CHANCES FRIDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 62 76 60 68 / 100 70 60 40
CLARKSVILLE 62 74 58 66 / 100 70 60 40
CROSSVILLE 61 71 59 67 / 100 80 60 60
COLUMBIA 62 75 60 67 / 100 60 60 40
LAWRENCEBURG 63 75 59 68 / 100 50 60 40
WAVERLY 62 75 59 69 / 100 60 60 30
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS AMARILLO TX
521 PM CDT SAT APR 18 2015
.UPDATE...
WEST TEXAS MESONET AND SCHOOL NET OBSERVATIONS SHOW A CONTINUED
DECREASE IN SURFACE DEW POINTS AND VEERING OF SURFACE WINDS ACROSS
THE FAR EASTERN PORTION OF THE TEXAS PANHANDLE. SPC RAP MESOANALYSIS
HAS RESPONDED BY DEPICTING MUCH HIGHER LCL HEIGHTS THAT ARE LESS
FAVORABLE FOR TORNADOES. A MORE FAVORABLE ENVIRONMENT EXISTS FURTHER
EAST INTO OKLAHOMA WHERE SURFACE WINDS REMAINED BACKED AND AT LEAST
SHALLOW LOW LEVEL MOISTURE /DEW POINTS IN THE MID TO UPPER 50S/ IS
PRESENT. A FAIRLY POTENT VORT MAX IS MOVING ACROSS THE TEXAS
PANHANDLE NOW AS SEEN ON WATER VAPOR LOOP AND THIS MAY RESULT IN AN
UPTICK IN CONVECTION OVER THE NEXT COUPLE OF HOURS. HAIL AND WIND
ARE STILL POSSIBLE WITH THE STRONGEST STORMS AS ENOUGH INSTABILITY
REMAINS INTO EARLY EVENING. WILL CONTINUE TO MONITOR TRENDS IN THE
OBSERVATIONS...ESPECIALLY LATER THIS EVENING WHEN MIXING SUBSIDES
AND THE DRYLINE POSSIBLY SHIFTS WESTWARD SOME. THE BEST CHANCE OF
BETTER LOW LEVEL MOISTURE RETURNING TO THE FORECAST AREA WILL BE
ACROSS WHEELER AND COLLINGSWORTH COUNTIES.
BRB
&&
.PREV DISCUSSION... /ISSUED 221 PM CDT SAT APR 18 2015/
DISCUSSION...
EARLY THIS AFTERNOON A DEEP CLOSED LOW WAS SITUATED OVER EASTERN
COLORADO AND SLOWLY MOVING EAST. A BAND OF CLOUDS ASSOCIATED WITH A
RELATIVELY POTENT VORT LOBE ROTATING AROUND THE MID-UPPER LOW WAS
EVIDENT IN IR/VIS SATELLITE. SURFACE OBSERVATIONS SHOW LIGHT RAIN
BENEATH THIS BAND OF CLOUDS AT CLAYTON NEW MEXICO AND PRESUMABLY
FURTHER SOUTH-SOUTHWEST EAST OF TUCUMCARI INTO THE FAR WESTERN TEXAS
PANHANDLE WHERE LIGHT ECHOS WERE PRESENT ON REGIONAL RADAR MOSAIC.
FURTHER EAST ACROSS THE TEXAS AND OKLAHOMA PANHANDLE LOW CLOUDS HAVE
DIMINISHED AND/OR SHIFTED INTO OKLAHOMA AS SURFACE WINDS CONTINUE TO
VEER SLIGHTLY. SHALLOW LOW LEVEL MOISTURE SEEN ON 12Z KAMA SOUNDING
REMAINS ACROSS THE EASTERN PANHANDLES EAST OF A DIFFUSE DRYLINE.
THERE REMAINS SOME UNCERTAINTY ON THE POSITION OF THE DRYLINE THAT
IS EXPECTED TO SHARPEN THIS AFTERNOON AS DIABATIC HEATING/MIXING
COMMENCES. USING SHORT RANGE MODEL FORECAST SOUNDINGS AS GUIDANCE ON
THE DEPTH OF MOISTURE OFF THE CAPROCK AND ESPECIALLY FURTHER EAST
NEAR THE OKLAHOMA BORDER LEADS TO FAIRLY HIGH CONFIDENCE ON THE
PREVIOUS FORECAST WHICH RELEGATES ANY SUBSTANTIAL DEEP CONVECTION TO
NEAR OR JUST EAST OF THE OKLAHOMA STATE LINE LATER THIS AFTERNOON.
LOW LEVEL MOISTURE IS DEEPER FROM THERE EASTWARD INTO OKLAHOMA AND
THUS DRYLINE CIRCULATION THAT DEVELOPS STANDS A BETTER CHANCE AT
INITIATING CONVECTION THERE THAN WAS THE CASE FURTHER WEST
YESTERDAY. SO THROUGH THE LATE AFTERNOON AND EVENING THERE IS ONLY A
LOW PROBABILITY OF ISOLATED-SCATTERED CONVECTION ACROSS THE EXTREME
EASTERN PORTION OF THE PANHANDLES WITH BETTER CHANCES OUT OF THE
FORECAST AREA ACROSS WESTERN OKLAHOMA. IF THE ABOVE ASSESSMENT IS
MISPLACED SLIGHTLY EAST THAN ANY STORM THAT DOES DEVELOP ON OUR SIDE
OF THE STATE LINE WOULD HAVE THE POTENTIAL TO BECOME SEVERE DUE TO
MODERATE INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR OF AROUND 30
KNOTS FOR STORM ORGANIZATION/PERSISTENCE. LARGE HAIL WOULD BE THE
PRIMARY THREAT INTO THE EVENING GIVEN STEEP MID LEVEL LAPSE RATES
OWING TO THE APPROACHING MID-UPPER LOW. WILL CONTINUE TO MONITOR
TRENDS IN SURFACE OBSERVATIONS AND DRYLINE EVOLUTION THROUGHOUT THE
AFTERNOON.
FURTHER WEST OF THE DRYLINE...DEEP MIXING WILL OCCUR GENERALLY EAST
OF THE AFOREMENTIONED BAND OF LOW-MID CLOUDS NOW ENTERING THE TEXAS
PANHANDLE. CU FIELD IS INCREASING IMMEDIATELY AHEAD OF THIS. BASES
SHOULD BECOME RELATIVELY HIGH AS MIXED LAYER DEEPENS THROUGH THE
AFTERNOON. WITH FORCING FROM PREVIOUSLY MENTIONED VORT LOBE
CONVECTION MAY BECOME DEEP ENOUGH FOR SHOWERS AND THUNDERSTORMS FOR
MUCH OF THE AREA LATER THIS AFTERNOON. IF CONVECTION BECOMES DEEP
ENOUGH FOR CHARGE SEPARATION AND LIGHTNING...LIMITED INSTABILITY
SHOULD PRECLUDE THE THREAT OF SEVERE THUNDERSTORMS. PROGNOSTICATIONS
FROM THE HI-RES CONVECTION ALLOWING GUIDANCE INCLUDING THE HRRR AND
TTU WRF SEEM TO LINE UP WELL WITH THE ABOVE THINKING.
AS THE MID-UPPER LOW CONTINUES TO SHIFT EAST A COLD FRONT WILL MOVE
THROUGH THE AREA TONIGHT. MODEL GUIDANCE IS IN AGREEMENT IN AN
EVOLUTION OF THE LOW INTO A MORE OPEN AND PROGRESSIVE WAVE THAT WILL
BE EAST OF THE AREA BY TOMORROW AFTERNOON. AN AREA OF MOISTURE ON
THE BACK SIDE OF THIS EVOLVING SHORTWAVE TROUGH FAVORABLY TIMED WITH
PEAK HEATING SHOULD BE ENOUGH FOR EXTENSIVE CUMULUS DEVELOPMENT
DURING THE AFTERNOON POSSIBLY ENOUGH FOR BROKEN SKY CONDITIONS
ESPECIALLY ACROSS THE EASTERN PORTION OF THE AREA. DEPTH OF
CONVECTION IN ROUGHLY THE NORTHEAST THIRD WILL NEED TO BE MONITORED
AS IT MAY BECOME SUFFICIENT FOR A FEW SHOWERS GIVEN RESIDUAL COOL MID
LEVEL TEMPERATURES AND RELATIVELY HIGH TQ INDEX VALUES. ADJUSTED LOW
POPS ON SUNDAY AFTERNOON TO EXTEND A BIT FURTHER SOUTH AND WEST TO
ACCOUNT FOR THIS.
EARLY NEXT WEEK A SPLIT UPPER FLOW PATTERN WILL EXIST WITH STRONG
PERIODICALLY PERTURBED WESTERLY SOUTHERN BRANCH JUST SOUTH OF US AND
NORTHWESTERLY NORTHERN BRANCH ACROSS THE CENTRAL PLAINS. MEAN
RIDGING WILL BE PRESENT OVER THE WESTERN STATES. GRADUALLY
INCREASING 500 MB HEIGHTS AND A SLIGHTLY MORE AMPLIFIED PATTERN WILL
EVOLVE THROUGH THE WEEK ESPECIALLY AS ANOTHER CLOSED LOW DEVELOPS
AND DEEPENS OVER THE SOUTHWESTERN CONUS BY THURSDAY. AS THIS MOVES
EAST THIS WILL PROBABLY RESULT IN ANOTHER CONVECTIVELY ACTIVE
PATTERN FOR THE LATTER HALF OF THE WEEK. AS IS TYPICALLY THE CASE AT
THAT TIME RANGE MODEL GUIDANCE DIFFERS IN TIMING AND AMPLITUDE BUT
THE SIGNAL IS THERE FOR A SCENARIO FAVORING A NORTH/WEST SURGE OF
LOW LEVEL MOISTURE AND FORCING FOR ASCENT RESULTING IN ABOVE CLIMO
PRECIPITATION PROBABILITIES AND THE POSSIBILITY OF SEVERE
THUNDERSTORMS BY MID AND ESPECIALLY LATE WEEK. EVEN BEFORE THEN
THERE WILL BE A FEW OPPORTUNITIES FOR PRECIPITATION EARLIER IN THE
WEEK AS DIFFICULT TO RESOLVE SMALL SHORTWAVE TROUGHS WITHIN MEAN
WEST-NORTHWESTERLY FLOW CROSS THE AREA. CONVECTION MAY EMANATE FROM
THE HIGHER TERRAIN OF COLORADO AND NEW MEXICO AND MOVE INTO THE
PANHANDLES LATE MONDAY AND AGAIN LATE TUESDAY...ALTHOUGH THIS
FORECAST WILL BE LESS DETERMINISTIC WITH TIMING OF HIGHER
PROBABILITIES OF PRECIPITATION AND MORE BROAD BRUSH GIVEN INHERENT
UNCERTAINTIES OF THIS TYPE PATTERN.
BRB
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
15/17
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
445 PM CDT SAT APR 18 2015
.DISCUSSION...
SENT OUT AN UPDATED FORECAST PACKAGE AND RAISED POPS AREA WIDE DUE
TO ONGOING/DEVELOPING CONVECTION ACROSS THE COASTAL COUNTIES AND
OFF THE COAST...AND FOR DEVELOPING STORMS OUT WEST THAT THE MODELS
HAVE MOVING INTO THE AREA THIS EVENING. SOME OF THE STORMS COULD
HAVE THE POTENTIAL TO BECOME STRONG OR SEVERE...WITH DAMAGING WINDS...
LARGE HAIL...AND LOCALLY HEAVY RAINFALL THE PRIMARY SEVERE WEATHER
THREATS. 42
&&
.PREV DISCUSSION... /ISSUED 340 PM CDT SAT APR 18 2015/
DISCUSSION...
THE UPPER LOW OVER EASTERN CO WILL OPEN UP AND SHEAR OUT OVER THE
PLAINS DURING THE NEXT DAY OR TWO. A COUPLE OF SHORTWAVE TROUGHS
MOVING OVERHEAD WILL BRING SCATTERED THUNDERSTORMS ACROSS SE TX
DURING A COUPLE OF EPISODES TONIGHT...THE FIRST DURING THE LATE
AFTERNOON AND EARLY EVENING AND THE SECOND FROM LATE EVENING
INTO THE OVERNIGHT PERIOD. CANNOT RULE OUT THE POSSIBILITY OF AN
ISOLATED OR STRONG THUNDERSTORM. ALTHOUGH THE MAIN STORM ACTION
WELL OFFSHORE OF THE COAST HAS BEEN STEALING MOST OF THE INFLOW
MOISTURE...THE LATEST SATELLITE TRENDS INDICATE THAT THE STORMS
NEAR MATAGORDA BAY WERE BEGINNING TO EXHIBIT COOLING CLOUD TOPS.
THERE IS ALSO A SLIGHT CHANCE THAT THE STORMS OVER THE FAR
SOUTHWESTERN SET OF COUNTIES MAY CONTAIN LOCALLY HEAVY RAINFALL
DURING THE REMAINING AFTERNOON HOURS. THE SECOND ROUND OF STORMS
WAS BEING FORECASTED BY THE HRRR AND TEXAS TECH WRF TO MOVE OVER
THE NORTHWESTERN AND NORTHERN SET OF COUNTIES BETWEEN ABOUT 9 PM
AND 2 AM OR SO. RAP FORECAST SOUNDING SHOW THE POTENTIAL FOR
ISOLATED STRONG OR SEVERE STORMS WITH THESE AS WELL.
HIGH PRESSURE SHOULD THEN BUILD OVERHEAD SUNDAY AND MONDAY AND
LOWER THE RAIN CHANCES. BOTH THE GFS AND ECMWF AGREE WITH ONSHORE
WINDS AND RAIN CHANCES RETURNING BY WEDNESDAY.
MARINE...
AN UPPER LEVEL DISTURBANCE WILL GENERATE SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS THE COASTAL WATERS THIS EVENING.
SOME STORMS COULD BE STRONG. OTHERWISE...ONSHORE FLOW WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL PUSH OFF THE COAST SUNDAY NIGHT
WITH MODERATE OFFSHORE WINDS IN ITS WAKE. WINDS WILL DIMINISH AND
VEER BACK TO THE SOUTHEAST BY LATE TUESDAY NIGHT AS HIGH PRESSURE
PUSHES OFF TO THE EAST. 47
PREV DISCUSSION... /ISSUED 1248 PM CDT SAT APR 18 2015/
AVIATION...
SAT IMAGERY SUGGESTS INLAND PORTIONS OF SE TX SHOULD START SEEING
SOME INTERMITTENT BREAKS OF SUN. ELSEWHERE...EXPECT TO SEE
IMPROVING CIG HEIGHTS IN THE NEXT COUPLE HOURS. THERE IS A SFC
BOUNDARY NEAR THE COAST...SO ADDITIONAL HEATING ALONG WITH
APPROACHING S/W FROM MID TX COAST SHOULD ALLOW FOR AT LEAST SOME
SCT TSRA TO DEVELOP THIS AFTN - ESP SOUTH OF A COLUMBUS-LIBERTY
LINE. (THIS IS ROUGHLY THE SAME LOCATIONS THAT SAW SOME SIG WX
YDAY SO WILL NEED TO KEEP A CLOSE EYE ON THINGS.) AREAS FURTHER N
WILL NEED TO KEEP AN EYE ON NW TX. MODELS ARE POINTING TOWARD A
DEVELOPING LINE OF SHRA/TSRA OUT THERE THIS AFTN...POSSIBLY MAKING
IT ESE TOWARD SE TX LATE EVNG & OVERNIGHT. WILL SEE HOW THIS ALL
PLAYS OUT, BUT WENT AHEAD AND THREW THE POTENTIAL OF THIS
OCCURRING IN THE 9-2AM TIMEFRAME IN THE CLL, UTS, CXO TAFS.
CONSIDERABLE UNCERTAINTY IN THIS ATTM BUT FEEL IT`S ENOUGH TO
BEGIN MENTIONING. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 63 85 56 75 54 / 50 20 10 10 20
HOUSTON (IAH) 64 85 61 78 57 / 50 20 20 10 10
GALVESTON (GLS) 69 81 66 77 66 / 50 20 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...42
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
251 PM MDT SAT APR 18 2015
.SYNOPSIS...
WINDS WILL TAPER OFF AFTER SUNSET THIS EVENING AS TEMPERATURES
COOL ACROSS THE BORDERLAND. DAYTIME CLOUDS WILL DISSOLVE LEAVING
SKIES MOSTLY CLEAR OVERNIGHT. SUNDAY WILL BE GENERALLY DRY AND
SUNNY AS A LOW PRESSURE SYSTEM BEGINS TO EXIT EAST. TEMPERATURES
WILL WARM ABOUT 5 DEGREES AND WINDS WILL BE NOTICEABLY LIGHTER.
JUST A BIT OF LINGERING MOISTURE ALOFT MAY ALLOW FOR A STRAY
ELEVATED THUNDERSTORM OVER THE MOUNTAINS IN THE AFTERNOON HOURS.
THE WEATHER REPEATS MONDAY. TUESDAY ONWARD STRONGER WINDS RETURN FOR
EACH AFTERNOON WITH THURSDAY LOOKING THE STRONGEST FOR THE WEEK.
GENERALLY DRY CONDITIONS LOOK TO HOLD FOR THE WEEK AHEAD BUT A
PACIFIC LOW PRESSURE SYSTEM DOES TRACK ACROSS THE REGION THURSDAY
TO BRING INCREASED CLOUDS...AND MAYBE A STRAY SHOWER OR STORM.
&&
.DISCUSSION...
LARGE UPPER-LEVEL LOW PRESSURE SYSTEM SPINS OVER E CO. IT IS
S-L-O-W-L-Y DRIFTING EAST TOWARDS KS. WE SIT UNDER THE SOUTHERN
PERIPHERY OF THIS SYSTEM WITH A BIT OF MID-LEVEL MOISTURE AND
LARGE-SCALE WEAK FORCING ALOFT. THE RESULT THUS FAR TODAY HAS BEEN
TO ROTATE A NICE CU-FIELD OVER THE NORTHERN ZONES FROM THE NW.
HOWEVER STILL NO ENHANCED RADAR ECHOS OR LIGHTNING. MOST OF THE
CU IS QUITE FLAT. VERY REASONABLE GIVEN THE ACTUAL 12Z SOUNDING
AND THE PROG 18-00Z SOUNDINGS. SHOULD BE A SHALLOW LAYER OF
MOISTURE WITH PW`S AT 1/3". MODELS DO SHOW THE ATMOSPHERE LEANING
TOWARD MARGINALLY UNSTABLE WITH LI`S NEAR 0 AND CAPE LESS THAN 100
J/KG. BOTTOM LINE IS THAT STORM POTENTIAL IS THERE...BUT IT IS
MARGINAL WITH ONLY ISOLATED AND WEAK STORMS. BOTH THE HRRR AND WRF
MODELS SHOW LATE AFTN/EARLY EVE STORMS OVER SIERRA/OTERO COUNTIES
AS DO THE GFS AND NAM. THUS SLIGHT CHANCE WORDING IN THE FORECAST
FOR THOSE AREAS FOR THE EVENING HOURS TONIGHT. THREATS/IMPACT WOULD
BE STRONG OUTFLOW WIND/LOW VSBY WITH DUST.
FOR SUNDAY IT APPEARS WE WILL SEE VERY SIMULAR WEATHER CONDITIONS
WITH REGARDS TO TODAY. WITH THE LOW EXITING AND HEIGHTS AND
THICKNESSES RISING ALONG WITH LIGHTER WINDS WE SHOULD GAIN ABOUT
5-7 DEGREES ON TEMPS SUNDAY. SUNDAY`S MOISTURE PROFILE RESEMBLES
TODAY`S WITH JUST A THIN LAYER OF MODERATELY MOIST AIR ALOFT. WE
WILL CONTINUE TO SEE VERY MINOR (WEAK) IMPULSES ALOFT TRACK OVER
IN WNW FLOW. WITH OROGRAPHICS WE COULD SEE A FEW MOUNTAIN
STORMS...BUT AGAIN ISOLATED AND WEAK. THE LOWLANDS SHOULD STAY
DRY. LIGHTER WINDS WILL BE THE BIGGER DEAL AS WINDS DROP BELOW THE
BREEZY CATEGORY OF 15 TO 25 MPH.
TUESDAY THE PATTERN BECOMES MORE SOUTHWEST ORIENTED AND THAT MEANS
WIND WILL BE ON THE INCREASE AGAIN. A DEEPENING PACIFIC TROUGH TO
OUR WEST AND A DEEPENING SURFACE TROUGH TO OUR EAST WILL TIGHTEN
GRADIENTS AND INCREASE WINDS. TUESDAY AND WEDNESDAY WILL BE DRY...
A FEW DEGREES WARMER THAN NORMAL...AND BREEZY.
THURSDAY THE WEST COAST LOW PRESSURE SYSTEM ARRIVES WITH WHAT
APPEARS TO BE MINIMAL MOISTURE. DESPITE APPEARING TO STRUGGLE WITH
IT THE MODELS DO SPIT OUT SOME QPF AND THUS WHAT LOOKS TO BE
ISOLATED SHOWERS AND THUNDERSTORMS. FOR NOW WE ARE IGNORING THE
SLIGHT PCPN POTENTIAL IN FAVOR WHAT WHAT SHOULD BE A LARGER
IMPACT...WIND. THURSDAY LOOKS WINDY BUT CLOUDS MAY TEMPER THE
SPEEDS A BIT.
FRIDAY THE PACIFIC STORM SYSTEM PASSES AND A MODERATELY WEAK
PACIFIC FRONT PUSHES IN TO BRING A SMALL BIT OF COOLING AND
LIGHTER WINDS. MODELS SUGGEST A SHORT WAVE RIDGE TO BUILD OVER THE
AREA SATURDAY ALLOWING TEMPS TO WARM WITH DRY CONDITIONS.
14-BIRD
&&
.AVIATION...VALID 19/00Z-20/00Z...
SCT-BKN CU FIELDS WILL PERSIST INTO THE EARLY EVENING HOURS
GENERALLY NORTH OF A SVC-LRU LINE...WITH BASES RUNNING BETWEEN 9-10K
FEET. A FEW ISOLATED SHOWERS MAY AFFECT AREAS NORTH OF TCS.
ELSEWHERE...MOSTLY CLEAR SKIES WILL PREVAIL. WEST TO NORTHWEST
WINDS WILL RANGE 15-20 KNOTS WITH GUSTS 25-30 KNOTS...WITH A FEW
HIGHER GUSTS POSSIBLE IN SW NEW MEXICO. WINDS WILL DIMINISH FAIRLY
QUICKLY AFTER SUNSET. EXPECT SIMILAR CONDITIONS TOMORROW WITH LOWER
WIND SPEEDS. A FEW ISOLATED CONVECTIVE SHOWERS OR EVEN A
THUNDERSTORM WILL AFFECT THE AREA TOMORROW...FAVORING AREAS NORTH OF
AN LSB-LRU LINE.
25-HARDIMAN
&&
.FIRE WEATHER...
WINDS WILL CONTINUE TO SLOWLY INCREASE OVER THEN NEXT FEW HOURS
DUE TO A STRONG UPPER LOW OVER COLORADO AND AN INCREASINGLY
STRONG PRESSURE GRADIENT. RH VALUES HAVE DROPPED INTO THE LOW AND
MID TEENS. CURRENT RED FLAG WARNING LOOKS GOOD AND WILL CONTINUE
THROUGH 8 PM. THE UPPER LOW WILL MOVE EAST INTO THE PLAINS
TOMORROW...WHILE A WEAK BACKDOOR COLD FRONT STALLS OUT OVER THE
AREA. A SECONDARY UPPER LEVEL DISTURBANCE AND THIS FRONT WILL
BRING A SLIGHT CHANCE FOR THUNDERSTORMS TO THE HIGHER TERRAIN
AREAS SUNDAY AFTERNOON AND EVENING. LIGHTER WINDS WILL PREVAIL
EARLY NEXT WEEK...WITH INCREASING SOUTHWEST FLOW BEYOND WEDNESDAY.
25-HARDIMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 52 80 54 82 55 / 0 0 0 0 0
SIERRA BLANCA 46 76 49 78 50 / 0 0 0 0 0
LAS CRUCES 45 78 48 79 48 / 0 0 0 0 0
ALAMOGORDO 45 76 49 78 49 / 0 10 10 0 0
CLOUDCROFT 34 56 36 58 39 / 10 10 10 10 0
TRUTH OR CONSEQUENCES 46 76 48 78 48 / 0 10 10 0 0
SILVER CITY 40 71 43 72 43 / 0 0 0 0 0
DEMING 42 80 44 80 45 / 0 0 0 0 0
LORDSBURG 40 79 43 80 43 / 0 0 0 0 0
WEST EL PASO METRO 52 80 55 81 55 / 0 0 0 0 0
DELL CITY 46 79 50 80 50 / 0 0 0 0 0
FORT HANCOCK 48 80 52 82 52 / 0 0 0 0 0
LOMA LINDA 48 73 50 75 52 / 0 0 0 0 0
FABENS 48 80 51 81 51 / 0 0 0 0 0
SANTA TERESA 47 80 50 80 50 / 0 0 0 0 0
WHITE SANDS HQ 50 77 53 79 53 / 0 0 0 0 0
JORNADA RANGE 40 78 44 79 44 / 0 0 0 0 0
HATCH 44 79 46 80 46 / 0 0 0 0 0
COLUMBUS 47 78 50 79 50 / 0 0 0 0 0
OROGRANDE 48 77 52 78 51 / 0 0 0 0 0
MAYHILL 39 64 39 66 43 / 10 10 10 0 0
MESCALERO 38 63 40 66 41 / 10 10 10 0 0
TIMBERON 39 64 41 66 42 / 10 10 10 0 0
WINSTON 36 69 39 72 39 / 10 10 10 0 0
HILLSBORO 42 75 44 77 45 / 0 10 10 0 0
SPACEPORT 41 78 44 79 44 / 0 0 10 0 0
LAKE ROBERTS 37 69 39 71 39 / 10 10 10 0 0
HURLEY 39 73 42 74 42 / 0 0 0 0 0
CLIFF 39 78 40 79 41 / 0 0 0 0 0
MULE CREEK 33 75 37 76 37 / 0 0 0 0 0
FAYWOOD 41 74 44 75 44 / 0 0 0 0 0
ANIMAS 44 79 47 79 47 / 0 0 0 0 0
HACHITA 42 79 45 80 45 / 0 0 0 0 0
ANTELOPE WELLS 42 78 46 79 46 / 0 0 0 0 0
CLOVERDALE 41 74 44 75 44 / 0 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR NMZ111-112.
TX...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR TXZ055-056.
&&
$$
14/25
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
340 PM CDT SAT APR 18 2015
.DISCUSSION...
THE UPPER LOW OVER EASTERN CO WILL OPEN UP AND SHEAR OUT OVER THE
PLAINS DURING THE NEXT DAY OR TWO. A COUPLE OF SHORTWAVE TROUGHS
MOVING OVERHEAD WILL BRING SCATTERED THUNDERSTORMS ACROSS SE TX
DURING A COUPLE OF EPISODES TONIGHT...THE FIRST DURING THE LATE
AFTERNOON AND EARLY EVENING AND THE SECOND FROM LATE EVENING
INTO THE OVERNIGHT PERIOD. CANNOT RULE OUT THE POSSIBILITY OF AN
ISOLATED OR STRONG THUNDERSTORM. ALTHOUGH THE MAIN STORM ACTION
WELL OFFSHORE OF THE COAST HAS BEEN STEALING MOST OF THE INFLOW
MOISTURE...THE LATEST SATELLITE TRENDS INDICATE THAT THE STORMS
NEAR MATAGORDA BAY WERE BEGINNING TO EXHIBIT COOLING CLOUD TOPS.
THERE IS ALSO A SLIGHT CHANCE THAT THE STORMS OVER THE FAR
SOUTHWESTERN SET OF COUNTIES MAY CONTAIN LOCALLY HEAVY RAINFALL
DURING THE REMAINING AFTERNOON HOURS. THE SECOND ROUND OF STORMS
WAS BEING FORECASTED BY THE HRRR AND TEXAS TECH WRF TO MOVE OVER
THE NORTHWESTERN AND NORTHERN SET OF COUNTIES BETWEEN ABOUT 9 PM
AND 2 AM OR SO. RAP FORECAST SOUNDING SHOW THE POTENTIAL FOR
ISOLATED STRONG OR SEVERE STORMS WITH THESE AS WELL.
HIGH PRESSURE SHOULD THEN BUILD OVERHEAD SUNDAY AND MONDAY AND
LOWER THE RAIN CHANCES. BOTH THE GFS AND ECMWF AGREE WITH ONSHORE
WINDS AND RAIN CHANCES RETURNING BY WEDNESDAY.
40
&&
.MARINE...
AN UPPER LEVEL DISTURBANCE WILL GENERATE SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS THE COASTAL WATERS THIS EVENING.
SOME STORMS COULD BE STRONG. OTHERWISE...ONSHORE FLOW WILL PERSIST
THROUGH SUNDAY. A COLD FRONT WILL PUSH OFF THE COAST SUNDAY NIGHT
WITH MODERATE OFFSHORE WINDS IN ITS WAKE. WINDS WILL DIMINISH AND
VEER BACK TO THE SOUTHEAST BY LATE TUESDAY NIGHT AS HIGH PRESSURE
PUSHES OFF TO THE EAST. 47
&&
.PREV DISCUSSION... /ISSUED 1248 PM CDT SAT APR 18 2015/
AVIATION...
SAT IMAGERY SUGGESTS INLAND PORTIONS OF SE TX SHOULD START SEEING
SOME INTERMITTENT BREAKS OF SUN. ELSEWHERE...EXPECT TO SEE
IMPROVING CIG HEIGHTS IN THE NEXT COUPLE HOURS. THERE IS A SFC
BOUNDARY NEAR THE COAST...SO ADDITIONAL HEATING ALONG WITH
APPROACHING S/W FROM MID TX COAST SHOULD ALLOW FOR AT LEAST SOME
SCT TSRA TO DEVELOP THIS AFTN - ESP SOUTH OF A COLUMBUS-LIBERTY
LINE. (THIS IS ROUGHLY THE SAME LOCATIONS THAT SAW SOME SIG WX
YDAY SO WILL NEED TO KEEP A CLOSE EYE ON THINGS.) AREAS FURTHER N
WILL NEED TO KEEP AN EYE ON NW TX. MODELS ARE POINTING TOWARD A
DEVELOPING LINE OF SHRA/TSRA OUT THERE THIS AFTN...POSSIBLY MAKING
IT ESE TOWARD SE TX LATE EVNG & OVERNIGHT. WILL SEE HOW THIS ALL
PLAYS OUT, BUT WENT AHEAD AND THREW THE POTENTIAL OF THIS
OCCURRING IN THE 9-2AM TIMEFRAME IN THE CLL, UTS, CXO TAFS.
CONSIDERABLE UNCERTAINTY IN THIS ATTM BUT FEEL IT`S ENOUGH TO
BEGIN MENTIONING. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 63 85 56 75 54 / 40 20 10 10 20
HOUSTON (IAH) 64 85 61 78 57 / 30 20 20 10 10
GALVESTON (GLS) 69 81 66 77 66 / 30 20 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...47
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
255 PM CDT SAT APR 18 2015
.SHORT TERM.../NOW THROUGH SUNDAY NIGHT/...A LOW PRESSURE SYSTEM
CENTERED OVER EASTERN COLORADO IS MAINTAINING A BROAD AREA OF
DIFFLUENT FLOW ALOFT OVER SOUTH CENTRAL TEXAS. ALSO ...A VERY
ACTIVE SUB TROPICAL JET WITH SHORTWAVES WITHIN THE FLOW IS MOVING
ACROSS SOUTH TX UNDERNEATH THIS LOW. THIS WILL CONTINUE TO PRODUCE
NUMEROUS SHOWERS AND THUNDERSTORMS ALONG THE LOWER TEXAS GULF
WATERS NORTHEAST INTO THE NORTHWEST GULF COAST. THERE IS AN AREA
OF CONVECTION DEVELOPING ALONG A STATIONARY FRONT WHICH IS
INTERACTING WITH PLENTY OF DEEP LAYER MOISTURE AND INSTABILITY
POOLED ALONG IT. NEAR THE SURFACE DEW POINTS RANGE FROM 70 TO 75
DEGREES AND PRECIPITABLE WATER VALUES IN THE LAST KBRO 12Z
SOUNDING SHOWS 1.96 INCHES AND THE LATEST RAP MODEL RUN SHOWS
PWATS OF 1.5 TO 1.9 INCHES ESPECIALLY FROM HIDALGO COUNTY
NORTHEAST AND EAST TOWARDS THE COAST. IN ADDITION...THE A SLIGHT
BREAK IN THE CLOUDS IS ALLOWING FOR TEMPS TO WARM UP FOR THE NEXT
FEW HOURS RESULTING IN INCREASE INSTABILITY ACROSS THE AREA. THIS
WILL RESULT IN A CONTINUATION OF THE CONVECTION IN THE LATE
AFTERNOON THROUGH THE OVERNIGHT HOURS THROUGH MIDNIGHT. THE
CONVECTION WILL ALSO BE ENHANCE ALONG THE SIERRA MADRE AND MOVE
NORTHEAST WHICH WILL MAKE ITS WAY INTO STARR AND HIDALGO COUNTY
LATE EVENING INTO THE OVERNIGHT. THE MAIN THREAT WITH THESE STORMS
WILL BE VERY HEAVY DOWNPOURS PRODUCING FLOODING...STRONG DAMAGING
WINDS...HAIL AND FREQUENT CG LIGHTNING. INTO SUNDAY THE UPPER
LEVEL JET WILL MAKE ITS WAY INTO SOUTH TEXAS PROVIDING SUPPORT FOR
SOME CONVECTION TO DEVELOP SUNDAY AFTERNOON. EXPECT THE BEST
POTENTIAL TO REMAIN ALONG THE COAST DUE TO THE INSTABILITY IN THE
AREA. EXPECT A FEW OF THE STORMS TO BECOME SEVERE. THE CLOSED LOW
BECOMES AN OPEN WAVE AS IT MOVES NORTHEAST INTO THE GREAT LAKES
SUNDAY NIGHT PUSHING A COLD FRONT BEHIND IT ALONG THE CENTRAL
PLAINS. THE CONVECTION WILL BE ENHANCE EVEN MORE OVERNIGHT SUNDAY
ASSOCIATED TO THE BOUNDARY AS THE FRONT APPROACHES THE AREA. THE
FRONT WILL ARRIVED BY THE END OF THE SHORT TERM OVER THE NORTHERN
RANCHLANDS EARLY MONDAY MORNING.
.LONG TERM.../MONDAY THROUGH SATURDAY/...THE CLOSED LOW THAT
HAS BEEN PLAUGING THE REGION WITH INTERMITTENT THUNDERSTORMS FOR
THE LAST SEVERAL DAYS OPENS UP AND MERGES WITH A SHARP SHORTWAVE
TROUGH UPPER TROUGH MOVING OUT OF CANADA. THE RESULT WILL BE A
LARGE SCALE UPPER TROUGH DEVELOPING MONDAY INTO TUESDAY FROM THE
NORTHERN PLAINS TO THE MIDWEST EXTENDING SOUTH INTO THE GULF
SOUTH. THIS SENDS A COLD FRONT THROUGH SOUTH TEXAS SUNDAY NIGHT
MOVING OFFSHORE THE LOWER TEXAS COAST AS EARLY AS SUNRISE MONDAY.
MODELS ARE IN GOOD AGREEMENT AND REMAIN VERY CONSISTENT WITH THE
EVOLUTION OF THE UPPER LEVEL AND SURFACE FEATURES. MODERATE TO
HIGH CONFIDENCE IN THE FORECAST THROUGH TUESDAY MAINTAINS A
LOWERING OF TEMPERATURES AND HIGHER CHANCES OF RAINFALL. THE
COOLING OF THE LOWER ATMOSPHERE, LOWER LAPSE RATES, WEAKENING
INSTABILITY WILL LIMIT THE THUNDERSTORM INTENSITY AND SEVERE
WEATHER PROBABILITIES GO WAY LOW. GFS MODEL SOUNDING CONTINUE TO
INDICATE THE BEST CHANCE OF THUNDER MONDAY MORNING AS THE FRONTAL
BOUNDARY PASSES THROUGH BUT AS THE COOLER SURFACE AIR SETTLES IN
THE INSTABILITY QUICKLY WEAKENS. ANY THUNDERSTORMS THAT LINGER
INTO THE MONDAY AFTERNOON AND EVENING WILL BE ELEVATED.
AS WE MOVE INTO TUESDAY AND THE REST OF THE WEEK THE FRONT
INITIALLY REMAINS STATIONARY NEAR OR JUST SOUTH OF THE REGION
KEEPING A MOIST EASTERLY FLOW AND POSSIBLY THE HIGHEST CHANCE OF
RAIN. BOTH GFS AND ECMWF INDICATE ON AVERAGE THAT TUESDAY WILL
HAVE THE BEST COVERAGE OF RAIN. THIS WILL ALSO KEEP TEMPERATURES
BELOW NORMAL.
AFTER TUESDAY FORECAST TRENDS DOWNWARD ON THE RAIN AND UP
WITH THE TEMPERATURES. THE FRONT EVENTUALLY DISSIPATES OR MOVES
BACK NORTH AS SHORTWAVE RIDGING BUILDS OVER WESTERN TEXAS WITH THE
NEXT UPPER TROUGH APPROACHING THE PACIFIC COAST. GFS AND ECMWF DO
LITTLE WITH THIS TROUGH AND IT LOOKS MUCH WEAKER THEN THE LAST FEW
TROUGHS. SOME PERTURBATIONS DO ADVANCE THROUGH THE TROUGH AND
RIDE ALONG STOUT SOUTHWESTERLY UPPER JET AND MAY SPARK SOME
AFTERNOON CONVECTION OVER THE SIERRA MADRE AND THEN DRIFT INTO OUR
CWA EACH AFTERNOON AND EVENING. THIS WILL BE INDICATED BY LOW
GRADE POPS EACH LATE DAY AND EVENING.
&&
.MARINE...NOW THROUGH SUNDAY NIGHT...THE SOUTHEAST WINDS WILL
REMAIN LIGHT TO VARIABLE WITH LOW SEAS ACROSS THE GULF WATERS.
THE MAIN CONCERNED THROUGH THE SHORT TERM WILL CONTINUE TO BE THE
CONVECTION OVER THE GULF. THERE IS ENOUGH INSTABILITY IN THE AREA
FROM A STATIONARY BOUNDARY PARALLEL TO THE COAST THAT WILL ENHANCE
MORE CONVECTION INCREASING LATE THIS AFTERNOON AND CONTINUE
OVERNIGHT. SUNDAY...THE POTENTIAL FOR CONVECTION WILL BEGIN TO
DEVELOP IN THE AFTERNOON AND CONTINUE OVERNIGHT AS A COLD FRONT IS
EXPECTED TO ARRIVED EARLY MONDAY INCREASING THE CHANCE OF RAIN
EVEN MORE AND SHIFTING WINDS NORTHERLY.
MONDAY THROUGH THURSDAY...COLD FRONT STILL ON TAP FOR EARLY
MONDAY AS HIGH PRESSURE BUILDS DOWN THE CENTRAL PLAINS AS A MID
LEVEL TROUGH DEEPENS INTO THE GULF SOUTH STATES. NORTHEAST WINDS
INCREASE APPROACHING SMALL CRAFT ADVISORY CONDITIONS MONDAY
AFTERNOON. SEAS TO RESPOND AND BUILD UPWARDS TO 6 FEET BY MONDAY
NIGHT. MODERATE NORTHEAST TO EAST WINDS PERSIST TUESDAY AS THE
FRONT BECOMES STATIONARY AND HIGH PRESSURE EXPANDS OVER THE
CENTRAL GULF. A RETURN TO SOUTHEAST WINDS WEDNESDAY WITH A GRADUAL
INCREASE THROUGH THE END OF THE WEEK IS EXPECTED. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS MONDAY AND TUESDAY WITH
DECREASING COVERAGE MID TO LATE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 72 86 72 77 / 20 20 30 40
BROWNSVILLE 71 87 72 78 / 20 40 30 50
HARLINGEN 71 90 71 80 / 20 40 40 50
MCALLEN 70 92 72 80 / 20 30 30 50
RIO GRANDE CITY 68 94 71 80 / 20 20 30 40
SOUTH PADRE ISLAND 72 79 72 76 / 20 20 30 40
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
67/59
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
227 PM CDT Sat Apr 18 2015
.UPDATE...
The Storm Prediction Center has just issued Severe Thunderstorm
Watch number 72, and it covers all of West Central Texas. So, we
just sent an update to our Zone forecast to include a watch
headline for all of our counties.
&&
.PREV DISCUSSION... /ISSUED 1249 PM CDT Sat Apr 18 2015/
AVIATION...
/18Z TAFS/
Expect VFR conditions to dominate for the next 24 hours and
thunderstorms this afternoon and evening. Thunderstorms will
likely impact Sonora, Brady, and Junction this afternoon and
evening.
PREV DISCUSSION... /ISSUED 631 AM CDT Sat Apr 18 2015/
AVIATION...
/12Z TAFS/
Two upper level disturbance will bring a round of storms to most
TAF sites this morning and again this afternoon. Latest radar data
is showing an area of storms moving east and northeast towards
KSOA and KJCT and could reach those sites between 12Z and 15Z.
Main impacts will be gusty winds, brief heavy rain, lightning and
low visibilities. The IFR Cigs should gradually improve to VFR shortly
after 15Z. The next round of storms may form along the dryline
after 18Z at KSOA, KBBD and KJCT. A few of these may become severe
and produce large hail, damaging winds and very heavy rainfall.
PREV DISCUSSION... /ISSUED 420 AM CDT Sat Apr 18 2015/
SHORT TERM...
(Today and Tonight)
There is a threat for severe thunderstorms across the eastern half
of West Central Texas today as an upper level trough associated with
the upper low near the Four Corners moves across the region. The
main threats will be large hail and damaging winds. SPC has placed
much of the area east of the dryline in a slight risk for severe
thunderstorms today.
Latest radar is showing showers developing across the mountains in
northern Mexico, south of Sanderson, in association with the next
approaching shortwave as can be seen on water vapor satellite
imagery. This could bring a round of showers and thunderstorms to
West Central Texas this morning before the main upper trough moves
across later this afternoon.
The dryline is forecast to move east today as the RUC model progs
this front from Haskell to just east of San Angelo to Sonora by
early evening. This dryline should trigger scattered thunderstorms
this afternoon as the following ingredients come together: dewpoints
ranging from the upper 50s to the lower 60s, moderate 0-6km shear,
MU CAPE Values 1500-2000 J/KG, a weak capping inversion, approaching
upper trough and a right rear entrance region of the southern stream
upper level jet flowing across the area. These parameters should
set the stage for the development of a few supercells today,
resulting in large hail and damaging winds. These storms may
continue into the early evening hours before dissipating.
Highest Pops were placed across the Northwest Hill Country extending
north to Brownwood. Went closer to the warmer MAV MOS for
temps as the dry warm air invades the western part of the region
today.
26
LONG TERM...
(Sunday through Friday)
Cold front will move through Sunday. Dry southwest to west winds
ahead of the front will not only preclude rain chances, but also
give a boost to temperatures, being downslope compression. Still,
cold advection will bring cooler temperatures Sunday, with highs
in the 70s.
Isolated dryline thunderstorms possible mid and late week. West
Central Texas will be under a broad upper ridge, so widespread
showers or thunderstorms not expected. Could see a few highs
approach 90s, especially Wednesday and Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 54 77 46 72 51 / 20 5 5 5 5
San Angelo 54 82 48 74 53 / 10 5 5 5 10
Junction 55 85 50 74 54 / 30 5 5 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
223 PM CDT SAT APR 18 2015
.UPDATE...
TO ISSUE SEVERE THUNDERSTORM WATCH 72. THUNDERSTORMS ARE BEGINNING
TO FORM ALONG THE DRYLINE AND ARE EXPECTED TO MOVE TO THE
SOUTHEAST AND INTO OUR CWA. CONDITIONS REMAIN FAVORALE FOR STORMS
TO BECOME SEVERE. WE HAVE ISSUED A SEVERE THUNDERSTOMR WATCH FOR
THE AREA FROM BURNET TO BANDERA TO VAL VERDE COUNTIES AND
NORTHWARD.
&&
.PREV DISCUSSION... /ISSUED 1256 PM CDT SAT APR 18 2015/
AVIATION...
ISOLD SHRA/TSRA ARE POSSIBLE EARLY THIS AFTERNOON. SHRA/TSRA WILL
DEVELOP ALONG THE DRYLINE THIS AFTERNOON NEAR THE EDWARDS PLATEAU
AND MOVE ACROSS THE HILL COUNTRY AND I-35 CORRIDOR AREAS LATE THIS
AFTERNOON INTO THIS EVENING. BEST CHANCES WILL BE AT KAUS/KSAT
WHERE HAVE GONE WITH TEMPO FROM 19/00Z TO 19/04Z. KSSF SHOULD BE
JUST SOUTH OF THE LINE WHILE SHRA/TSRA WILL DISSIPATE WHEN THEY
DRIFT OF THE SERRANIAS DEL BURRO WITH NO IMPACT TO KDRT. AREAS OF
MVFR CIGS WILL LIFT TO VFR SCT-BKN SKIES BY MID AFTERNOON. MVFR
CIGS WILL REDEVELOP OVERNIGHT. DRIER AIR WILL FILTER IN FROM THE
WEST ON SUNDAY WITH A RETURN TO VFR SKIES BY MIDDAY. NELY WINDS
LESS THAN 7 KTS WILL TURN TO SELY THIS AFTERNOON AND THEN SLY
TONIGHT AND THEN WLY ON SUNDAY. WIND GUSTS TO 50 KTS ARE POSSIBLE
IN AND NEAR TSRA.
PREV DISCUSSION... /ISSUED 1201 PM CDT SAT APR 18 2015/
UPDATE...
CONVECTION HAS BEEN A LITTLE SLOWER TO BEGIN THIS MORNING. HAVE
REDUCED POPS FOR THE NEXT COUPLE OF HOURS...ESPECIALLY ACROSS THE
EASTERN HALF OF THE CWA. SPC HAS UPDATED THE DAY ONE OUTLOOK AND
INCREASED OUR RISK TO ENHANCED. EXPECTING STRONG TO SEVERE STORMS
TO FORM LATER THIS AFTERNOON ALONG THE DRYLINE WHICH CURRENTLY
STRETCHES FROM AROUND CHILDRESS TO MIDLAND TO THE BIG BEND. THESE
STORMS WILL MOVE EASTWARD AND INTO OUR NORTHERN AREA LATE THIS
AFTERNOON OR EARLY EVENING. THE MAIN THREAT LOOKS TO BE LARGE HAIL
AND DAMAGING WINDS. THERE IS ALSO A LESSER THREAT FOR TORNADOES. WITH
ALL OF THE RAIN OVER THE PAST COUPLE OF DAYS LOCALLY HEAVY
RAINFALL IN STORMS WILL RUNOFF QUICKLY AND MAY CAUSE FLASH
FLOODING...BUT THIS IS NOT A WIDESPREAD THREAT.
PREV DISCUSSION... /ISSUED 611 AM CDT SAT APR 18 2015/
AVIATION...
CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND
CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON.
CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE
FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING
CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST
LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS
MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON
HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST
OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE
TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS
FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT
IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA.
HAMPSHIRE
PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS
MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN
EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY
AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL
LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18
HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE
EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE
WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND
WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE
FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS
SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO
-10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT
DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC
DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE
EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER
A SLIGHT RISK OF SEVERE THUNDERSTORMS.
HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF
STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE
SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND
MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING
STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE
EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP
CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR
TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS
ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS
EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW
PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH
MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE
WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT
AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY
AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT
WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT
TEMPS INTO THE 50S AREAWIDE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS
AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY.
SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR
SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY
AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 61 89 57 76 57 / 40 - - 0 20
AUSTIN BERGSTROM INTL AIRPORT 60 87 55 76 56 / 40 - - 0 20
NEW BRAUNFELS MUNI AIRPORT 60 87 56 76 56 / 30 0 10 - 20
BURNET MUNI AIRPORT 57 87 53 74 54 / 40 0 0 0 20
DEL RIO INTL AIRPORT 59 90 59 79 61 / 20 0 - 10 20
GEORGETOWN MUNI AIRPORT 59 87 54 74 54 / 40 - - 0 20
HONDO MUNI AIRPORT 59 88 57 78 58 / 20 0 - - 30
SAN MARCOS MUNI AIRPORT 61 86 56 75 56 / 40 0 10 - 20
LA GRANGE - FAYETTE REGIONAL 63 86 57 75 58 / 40 10 10 - 20
SAN ANTONIO INTL AIRPORT 61 88 58 77 59 / 30 0 - - 30
STINSON MUNI AIRPORT 61 88 59 77 59 / 20 0 10 - 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...01
AREA FORECAST DISCUSSION
NWS AMARILLO TX
221 PM CDT SAT APR 18 2015
.DISCUSSION...
EARLY THIS AFTERNOON A DEEP CLOSED LOW WAS SITUATED OVER EASTERN
COLORADO AND SLOWLY MOVING EAST. A BAND OF CLOUDS ASSOCIATED WITH A
RELATIVELY POTENT VORT LOBE ROTATING AROUND THE MID-UPPER LOW WAS
EVIDENT IN IR/VIS SATELLITE. SURFACE OBSERVATIONS SHOW LIGHT RAIN
BENEATH THIS BAND OF CLOUDS AT CLAYTON NEW MEXICO AND PRESUMABLY
FURTHER SOUTH-SOUTHWEST EAST OF TUCUMCARI INTO THE FAR WESTERN TEXAS
PANHANDLE WHERE LIGHT ECHOS WERE PRESENT ON REGIONAL RADAR MOSAIC.
FURTHER EAST ACROSS THE TEXAS AND OKLAHOMA PANHANDLE LOW CLOUDS HAVE
DIMINISHED AND/OR SHIFTED INTO OKLAHOMA AS SURFACE WINDS CONTINUE TO
VEER SLIGHTLY. SHALLOW LOW LEVEL MOISTURE SEEN ON 12Z KAMA SOUNDING
REMAINS ACROSS THE EASTERN PANHANDLES EAST OF A DIFFUSE DRYLINE.
THERE REMAINS SOME UNCERTAINTY ON THE POSITION OF THE DRYLINE THAT
IS EXPECTED TO SHARPEN THIS AFTERNOON AS DIABATIC HEATING/MIXING
COMMENCES. USING SHORT RANGE MODEL FORECAST SOUNDINGS AS GUIDANCE ON
THE DEPTH OF MOISTURE OFF THE CAPROCK AND ESPECIALLY FURTHER EAST
NEAR THE OKLAHOMA BORDER LEADS TO FAIRLY HIGH CONFIDENCE ON THE
PREVIOUS FORECAST WHICH RELEGATES ANY SUBSTANTIAL DEEP CONVECTION TO
NEAR OR JUST EAST OF THE OKLAHOMA STATE LINE LATER THIS AFTERNOON.
LOW LEVEL MOISTURE IS DEEPER FROM THERE EASTWARD INTO OKLAHOMA AND
THUS DRYLINE CIRCULATION THAT DEVELOPS STANDS A BETTER CHANCE AT
INITIATING CONVECTION THERE THAN WAS THE CASE FURTHER WEST
YESTERDAY. SO THROUGH THE LATE AFTERNOON AND EVENING THERE IS ONLY A
LOW PROBABILITY OF ISOLATED-SCATTERED CONVECTION ACROSS THE EXTREME
EASTERN PORTION OF THE PANHANDLES WITH BETTER CHANCES OUT OF THE
FORECAST AREA ACROSS WESTERN OKLAHOMA. IF THE ABOVE ASSESSMENT IS
MISPLACED SLIGHTLY EAST THAN ANY STORM THAT DOES DEVELOP ON OUR SIDE
OF THE STATE LINE WOULD HAVE THE POTENTIAL TO BECOME SEVERE DUE TO
MODERATE INSTABILITY AND SUFFICIENT DEEP LAYER SHEAR OF AROUND 30
KNOTS FOR STORM ORGANIZATION/PERSISTENCE. LARGE HAIL WOULD BE THE
PRIMARY THREAT INTO THE EVENING GIVEN STEEP MID LEVEL LAPSE RATES
OWING TO THE APPROACHING MID-UPPER LOW. WILL CONTINUE TO MONITOR
TRENDS IN SURFACE OBSERVATIONS AND DRYLINE EVOLUTION THROUGHOUT THE
AFTERNOON.
FURTHER WEST OF THE DRYLINE...DEEP MIXING WILL OCCUR GENERALLY EAST
OF THE AFOREMENTIONED BAND OF LOW-MID CLOUDS NOW ENTERING THE TEXAS
PANHANDLE. CU FIELD IS INCREASING IMMEDIATELY AHEAD OF THIS. BASES
SHOULD BECOME RELATIVELY HIGH AS MIXED LAYER DEEPENS THROUGH THE
AFTERNOON. WITH FORCING FROM PREVIOUSLY MENTIONED VORT LOBE
CONVECTION MAY BECOME DEEP ENOUGH FOR SHOWERS AND THUNDERSTORMS FOR
MUCH OF THE AREA LATER THIS AFTERNOON. IF CONVECTION BECOMES DEEP
ENOUGH FOR CHARGE SEPARATION AND LIGHTNING...LIMITED INSTABILITY
SHOULD PRECLUDE THE THREAT OF SEVERE THUNDERSTORMS. PROGNOSTICATIONS
FROM THE HI-RES CONVECTION ALLOWING GUIDANCE INCLUDING THE HRRR AND
TTU WRF SEEM TO LINE UP WELL WITH THE ABOVE THINKING.
AS THE MID-UPPER LOW CONTINUES TO SHIFT EAST A COLD FRONT WILL MOVE
THROUGH THE AREA TONIGHT. MODEL GUIDANCE IS IN AGREEMENT IN AN
EVOLUTION OF THE LOW INTO A MORE OPEN AND PROGRESSIVE WAVE THAT WILL
BE EAST OF THE AREA BY TOMORROW AFTERNOON. AN AREA OF MOISTURE ON
THE BACK SIDE OF THIS EVOLVING SHORTWAVE TROUGH FAVORABLY TIMED WITH
PEAK HEATING SHOULD BE ENOUGH FOR EXTENSIVE CUMULUS DEVELOPMENT
DURING THE AFTERNOON POSSIBLY ENOUGH FOR BROKEN SKY CONDITIONS
ESPECIALLY ACROSS THE EASTERN PORTION OF THE AREA. DEPTH OF
CONVECTION IN ROUGHLY THE NORTHEAST THIRD WILL NEED TO BE MONITORED
AS IT MAY BECOME SUFFICIENT FOR A FEW SHOWERS GIVEN RESIDUAL COOL MID
LEVEL TEMPERATURES AND RELATIVELY HIGH TQ INDEX VALUES. ADJUSTED LOW
POPS ON SUNDAY AFTERNOON TO EXTEND A BIT FURTHER SOUTH AND WEST TO
ACCOUNT FOR THIS.
EARLY NEXT WEEK A SPLIT UPPER FLOW PATTERN WILL EXIST WITH STRONG
PERIODICALLY PERTURBED WESTERLY SOUTHERN BRANCH JUST SOUTH OF US AND
NORTHWESTERLY NORTHERN BRANCH ACROSS THE CENTRAL PLAINS. MEAN
RIDGING WILL BE PRESENT OVER THE WESTERN STATES. GRADUALLY
INCREASING 500 MB HEIGHTS AND A SLIGHTLY MORE AMPLIFIED PATTERN WILL
EVOLVE THROUGH THE WEEK ESPECIALLY AS ANOTHER CLOSED LOW DEVELOPS
AND DEEPENS OVER THE SOUTHWESTERN CONUS BY THURSDAY. AS THIS MOVES
EAST THIS WILL PROBABLY RESULT IN ANOTHER CONVECTIVELY ACTIVE
PATTERN FOR THE LATTER HALF OF THE WEEK. AS IS TYPICALLY THE CASE AT
THAT TIME RANGE MODEL GUIDANCE DIFFERS IN TIMING AND AMPLITUDE BUT
THE SIGNAL IS THERE FOR A SCENARIO FAVORING A NORTH/WEST SURGE OF
LOW LEVEL MOISTURE AND FORCING FOR ASCENT RESULTING IN ABOVE CLIMO
PRECIPITATION PROBABILITIES AND THE POSSIBILITY OF SEVERE
THUNDERSTORMS BY MID AND ESPECIALLY LATE WEEK. EVEN BEFORE THEN
THERE WILL BE A FEW OPPORTUNITIES FOR PRECIPITATION EARLIER IN THE
WEEK AS DIFFICULT TO RESOLVE SMALL SHORTWAVE TROUGHS WITHIN MEAN
WEST-NORTHWESTERLY FLOW CROSS THE AREA. CONVECTION MAY EMANATE FROM
THE HIGHER TERRAIN OF COLORADO AND NEW MEXICO AND MOVE INTO THE
PANHANDLES LATE MONDAY AND AGAIN LATE TUESDAY...ALTHOUGH THIS
FORECAST WILL BE LESS DETERMINISTIC WITH TIMING OF HIGHER
PROBABILITIES OF PRECIPITATION AND MORE BROAD BRUSH GIVEN INHERENT
UNCERTAINTIES OF THIS TYPE PATTERN.
BRB
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
05/17
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1256 PM CDT SAT APR 18 2015
.AVIATION...
ISOLD SHRA/TSRA ARE POSSIBLE EARLY THIS AFTERNOON. SHRA/TSRA WILL
DEVELOP ALONG THE DRYLINE THIS AFTERNOON NEAR THE EDWARDS PLATEAU
AND MOVE ACROSS THE HILL COUNTRY AND I-35 CORRIDOR AREAS LATE THIS
AFTERNOON INTO THIS EVENING. BEST CHANCES WILL BE AT KAUS/KSAT
WHERE HAVE GONE WITH TEMPO FROM 19/00Z TO 19/04Z. KSSF SHOULD BE
JUST SOUTH OF THE LINE WHILE SHRA/TSRA WILL DISSIPATE WHEN THEY
DRIFT OF THE SERRANIAS DEL BURRO WITH NO IMPACT TO KDRT. AREAS OF
MVFR CIGS WILL LIFT TO VFR SCT-BKN SKIES BY MID AFTERNOON. MVFR
CIGS WILL REDEVELOP OVERNIGHT. DRIER AIR WILL FILTER IN FROM THE
WEST ON SUNDAY WITH A RETURN TO VFR SKIES BY MIDDAY. NELY WINDS
LESS THAN 7 KTS WILL TURN TO SELY THIS AFTERNOON AND THEN SLY
TONIGHT AND THEN WLY ON SUNDAY. WIND GUSTS TO 50 KTS ARE POSSIBLE
IN AND NEAR TSRA.
&&
.PREV DISCUSSION... /ISSUED 1201 PM CDT SAT APR 18 2015/
UPDATE...
CONVECTION HAS BEEN A LITTLE SLOWER TO BEGIN THIS MORNING. HAVE
REDUCED POPS FOR THE NEXT COUPLE OF HOURS...ESPECIALLY ACROSS THE
EASTERN HALF OF THE CWA. SPC HAS UPDATED THE DAY ONE OUTLOOK AND
INCREASED OUR RISK TO ENHANCED. EXPECTING STRONG TO SEVERE STORMS
TO FORM LATER THIS AFTERNOON ALONG THE DRYLINE WHICH CURRENTLY
STRETCHES FROM AROUND CHILDRESS TO MIDLAND TO THE BIG BEND. THESE
STORMS WILL MOVE EASTWARD AND INTO OUR NORTHERN AREA LATE THIS
AFTERNOON OR EARLY EVENING. THE MAIN THREAT LOOKS TO BE LARGE HAIL
AND DAMAGING WINDS. THERE IS ALSO A LESSER THREAT FOR TORNADOES. WITH
ALL OF THE RAIN OVER THE PAST COUPLE OF DAYS LOCALLY HEAVY
RAINFALL IN STORMS WILL RUNOFF QUICKLY AND MAY CAUSE FLASH
FLOODING...BUT THIS IS NOT A WIDESPREAD THREAT.
PREV DISCUSSION... /ISSUED 611 AM CDT SAT APR 18 2015/
AVIATION...
CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND
CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON.
CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE
FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING
CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST
LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS
MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON
HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST
OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE
TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS
FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT
IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA.
HAMPSHIRE
PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS
MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN
EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY
AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL
LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18
HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE
EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE
WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND
WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE
FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS
SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO
-10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT
DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC
DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE
EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER
A SLIGHT RISK OF SEVERE THUNDERSTORMS.
HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF
STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE
SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND
MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING
STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE
EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP
CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR
TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS
ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS
EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW
PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH
MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE
WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT
AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY
AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT
WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT
TEMPS INTO THE 50S AREAWIDE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS
AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY.
SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR
SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY
AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - -
AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - -
NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - -
BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - -
DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10
GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - -
HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - -
SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - -
LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10
SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - -
STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...01
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1249 PM CDT SAT APR 18 2015
.AVIATION...
THE UPPER LOW NOW SPINNING OVER COLORADO WILL MOVE EAST ACROSS THE
PLAINS OVER THE NEXT 24 HOURS. A SHORTWAVE TROUGH WORKING ITS WAY
AROUND THE SOUTH SIDE OF THE UPPER LOW WILL MOVE ACROSS CENTRAL
TEXAS THIS AFTERNOON...AIDING IN THE DEVELOPMENT OF SCATTERED
SHOWERS AND THUNDERSTORMS WEST OF THE TAF LOCATIONS LATE THIS
AFTERNOON. CONVECTION WILL SPREAD EAST ACROSS NORTH TEXAS THIS
EVENING. TIMING WILL BE A CHALLENGE...BUT THE LATEST HI-RES
GUIDANCE ONCE AGAIN PINPOINTS THE 00-04Z TIME FRAME AS THE MOST
LIKELY AT ALL TAF LOCATIONS THIS EVENING. CONVECTION SHOULD MOVE
EAST OF THE AREA AND WEAKEN AROUND MIDNIGHT LOCAL.
A COLD FRONT WILL PUSH SOUTHEAST ACROSS NORTH TEXAS TOMORROW.
SOUTH TO SOUTHWEST WINDS WILL INCREASE TO 10-15 KT AROUND SUNRISE
AHEAD OF THE FRONT. WINDS WILL VEER TO THE WEST SHORTLY AFTER 18Z
WHILE INCREASING TO 15-20 KT. NORTHWEST WINDS ARE EXPECTED AT ALL
LOCATIONS BY 00Z SUNDAY EVENING. AT THIS TIME...IT APPEARS THAT
ANY CONVECTION ASSOCIATED WITH THE FRONT WILL REMAIN EAST OF ALL
TAF SITES.
30
&&
.UPDATE...
MORNING UPPER AIR DATA AND SHORT-TERM MODEL GUIDANCE HAS
IDENTIFIED A SHORTWAVE TROUGH THAT IS PIVOTING AROUND THE UPPER
LOW OVER COLORADO. THIS SHORTWAVE WILL TRACK THROUGH TEXAS THIS
AFTERNOON AND EVENING. A DRY LINE IS FORECAST TO SET UP JUST WEST
OF THE CWA BORDER THIS AFTERNOON AND WILL BECOME THE FOCUS FOR
SCATTERED CONVECTION WHEN FORCING FROM THE SHORTWAVE TROUGH
ARRIVES. CONVECTIVE INITIATION SHOULD START AFTER 3 PM JUST WEST
OF THE CWA...WITH THESE STORMS MOVING/DEVELOPING GRADUALLY
NORTHEASTWARD INTO AND THROUGH THE CWA DURING THE LATE AFTERNOON
AND EVENING HOURS. GIVEN THE EXPECTED TIMING...HAVE LOWERED THE
POPS ALONG AND EAST OF I-35 FOR THE TODAY PERIOD AS ANY
RAIN/STORMS SHOULD HOLD OFF UNTIL THIS EVENING FOR THESE AREAS.
THERE IS A LACK OF LOW LEVEL WIND FLOW EVIDENT IN THE MORNING
DATA AND THE AIRMASS HAS BEEN FAIRLY WORKED OVER BY THE CONVECTION
FROM YESTERDAY AND LAST NIGHT. HOWEVER THE APPROACH OF THE
SHORTWAVE TROUGH WILL HELP TURN WINDS TO THE SOUTH BY THE
AFTERNOON...THEREBY INCREASING MOISTURE/THETA-E ADVECTION AND BULK
SHEAR VALUES ACROSS NORTH TEXAS. TEMPERATURES WILL ALSO WARM INTO
THE UPPER 70S AND LOWER 80S OVER NORTH TEXAS TODAY...WHICH WILL
YIELD GENERALLY 1000-2000 J/KG OF SURFACE BASED CAPE. THUS THE
AIRMASS SHOULD BE RECHARGED JUST ENOUGH TO SUPPORT SCATTERED
CONVECTION WITH A POTENTIAL FOR SEVERE WIND AND HAIL...ESPECIALLY
WEST OF I-35 IN THE LATE AFTERNOON HOURS. THE SEVERE THREAT WILL
DIMINISH AS THE STORMS HEAD EAST OF I-35 DUE TO THE LOSS OF
HEATING AND INCREASING CINH.
TR.92
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 18 2015/
THE UPPER LOW THAT HAS BEEN PARKED OVER THE FOUR CORNERS IS
BEGINNING TO DISLODGE...AND BY THIS TIME SUNDAY MORNING IT WILL BE
OVER THE HIGH PLAINS NEAR THE COLORADO/KANSAS BORDER. THIS WILL
STEADILY VEER THE 700MB FLOW ACROSS WEST TEXAS TODAY...HELPING TO
NUDGE THE DRYLINE FARTHER EAST THAN IN RECENT DAYS. ALTHOUGH
WITHIN THE FIRST 24 HOURS OF THE LATEST GUIDANCE...OPERATIONAL
SOLUTIONS VARY WIDELY ON THE LATE AFTERNOON POSITION. ALTHOUGH THE
NAM IS AMONG THE FARTHEST WEST...WHICH IS UNUSUAL IN THIS
SCENARIO...THE CONSENSUS AMONG THE MESOSCALE GUIDANCE IS FOR THE
BOUNDARY TO REACH A VERNON-SAN ANGELO LINE NEAR PEAK HEATING. OUR
FORECAST WILL FAVOR THIS POSITION. BASED ON THE MID-LEVEL FLOW...
THERE SHOULD BE A BULGE NEAR THE RED RIVER. THE RAP AND TTU WRF
SHOW THIS CLEARLY...ADDING TO THE CONFIDENCE IN THEIR EVOLUTION OF
THE BOUNDARY TODAY.
THE ATMOSPHERE ACROSS NORTH TEXAS HAS BEEN WELL WORKED OVER. THIS
STABILITY...COUPLED WITH SUBSIDENCE IN THE WAKE OF A DEPARTING
DISTURBANCE...SHOULD PRECLUDE MUCH ADDITIONAL PRECIPITATION THIS
MORNING. WEAK LOW-LEVEL FLOW WILL RESULT IN NEGLIGIBLE MOIST
ADVECTION TODAY...AND DESTABILIZATION THIS AFTERNOON WILL BE
PRIMARILY GOVERNED BY SURFACE HEATING. ALTHOUGH THE I-35 CORRIDOR
WILL BE SLOW TO CLEAR TODAY...WESTERN NORTH TEXAS WILL SEE
SUFFICIENT SUNSHINE. EXPECT THUNDERSTORMS TO DEVELOP ALONG THE
DRYLINE MID TO LATE AFTERNOON. THOUGH RELATIVELY WEAK...THE
STEERING FLOW ALOFT SHOULD GUIDE THE ACTIVITY EAST THROUGH NORTH
TEXAS THIS EVENING. EVEN THOUGH THE SURFACE LAYER WILL BE
STEADILY STABILIZING AT THAT TIME...THE COLD POOL ASSOCIATED WITH
AN ORGANIZED MCS SHOULD PROLONG THE LIFESPAN OF ITS UPDRAFTS. THIS
WILL MAINTAIN A HAIL THREAT WELL INTO THE EVENING. THIS IS NOT THE
TYPICAL SETUP FOR A SQUALL LINE...BUT A WELL ORGANIZED COMPLEX
COULD POSE A WIND THREAT AS WELL. THE SPEED SHOULD BE SUFFICIENT
TO AVOID SIGNIFICANT FLOODING CONCERNS IN MOST AREAS...BUT WHERE
HEAVY RAIN HAS FALLEN RECENTLY...ADDITIONAL RAINFALL COULD
REAGGRAVATE FLOODING ISSUES.
AS THE UPPER LOW EJECTS THROUGH THE CENTRAL PLAINS...IT WILL SURGE
A COLD FRONT THROUGH THE REGION. WITH WIDESPREAD ACTIVITY THIS
EVENING...LARGE-SCALE SUBSIDENCE INVADING...AND VEERING LOW-LEVEL
FLOW EARLY SUNDAY...THE ATMOSPHERE SHOULD BE UNABLE TO PRODUCE ANY
FRONTAL PRECIPITATION. THE EXCEPTION WOULD BE EAST TEXAS...WHERE
THE MOISTURE PROFILE WILL BE MORE FAVORABLE...AND THE FRONT WILL
ARRIVE DURING THE WARM AFTERNOON HOURS. ABUNDANT APRIL SUNSHINE
AND A PRONOUNCED DOWNSLOPE WIND SHOULD OFFSET ANY COLD ADVECTION
BEHIND THE FRONT...AND TEMPERATURES SHOULD REACH THE 80S IN MANY
AREAS SUNDAY AFTERNOON. THE COOL AIR WILL ARRIVE SUNDAY NIGHT...
AND RURAL AREAS IN THE NORTHERN HALF OF THE CWA WILL LIKELY DIP
INTO THE 40S MONDAY AND TUESDAY MORNING.
ZONAL FLOW WILL PREVAIL MUCH OF THE UPCOMING WEEK. THE NEXT WAVE
EMBEDDED IN THIS WESTERLY FLOW WILL ARRIVE AROUND TUESDAY...BUT
AT THAT TIME...BOUNDARY LAYER MOISTURE MAY NOT HAVE BEEN ABLE TO
SUFFICIENTLY RECOVER. ADDITIONAL RIPPLES WILL FOLLOW...MAINTAINING
RAIN CHANCES. HOWEVER...POPS ARE NOTHING MORE THAN CLIMATOLOGY.
EXTENDED GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH
UNSEASONABLE STRONG SHORTWAVE RIDGING AS THE NEXT UPPER LOW ENTERS
THE DESERT SOUTHWEST. GFS MOS TEMPS FOR THURSDAY AND FRIDAY ARE
NEAR 90 DEGREES. WITH PERFECT PROG 850MB TEMPS AROUND 20C...THIS
IS NOT OUT OF THE QUESTION. A BIT CONCERNED THAT CLOUD COVER MAY
PUT A DAMPER ON THE SPRING FEVER...AND FOR NOW...WILL KEEP
TEMPERATURES CLOSER TO CLIMATOLOGY.
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 60 80 53 73 / 20 50 10 5 5
WACO, TX 80 60 83 53 75 / 20 50 10 5 5
PARIS, TX 75 58 77 50 70 / 20 40 20 5 0
DENTON, TX 77 57 79 49 72 / 30 50 10 5 5
MCKINNEY, TX 78 58 79 51 73 / 20 50 10 5 0
DALLAS, TX 80 62 81 54 74 / 20 50 10 5 5
TERRELL, TX 78 60 80 52 74 / 20 50 10 5 5
CORSICANA, TX 79 61 82 52 75 / 20 50 20 5 5
TEMPLE, TX 79 60 84 53 74 / 20 50 10 5 5
MINERAL WELLS, TX 81 55 79 48 74 / 40 50 10 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
30/92
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1248 PM CDT SAT APR 18 2015
.AVIATION...
SAT IMAGERY SUGGESTS INLAND PORTIONS OF SE TX SHOULD START SEEING
SOME INTERMITTENT BREAKS OF SUN. ELSEWHERE...EXPECT TO SEE
IMPROVING CIG HEIGHTS IN THE NEXT COUPLE HOURS. THERE IS A SFC
BOUNDARY NEAR THE COAST...SO ADDITIONAL HEATING ALONG WITH
APPROACHING S/W FROM MID TX COAST SHOULD ALLOW FOR AT LEAST SOME
SCT TSRA TO DEVELOP THIS AFTN - ESP SOUTH OF A COLUMBUS-LIBERTY
LINE. (THIS IS ROUGHLY THE SAME LOCATIONS THAT SAW SOME SIG WX
YDAY SO WILL NEED TO KEEP A CLOSE EYE ON THINGS.) AREAS FURTHER N
WILL NEED TO KEEP AN EYE ON NW TX. MODELS ARE POINTING TOWARD A
DEVELOPING LINE OF SHRA/TSRA OUT THERE THIS AFTN...POSSIBLY MAKING
IT ESE TOWARD SE TX LATE EVNG & OVERNIGHT. WILL SEE HOW THIS ALL
PLAYS OUT, BUT WENT AHEAD AND THREW THE POTENTIAL OF THIS
OCCURRING IN THE 9-2AM TIMEFRAME IN THE CLL, UTS, CXO TAFS.
CONSIDERABLE UNCERTAINTY IN THIS ATTM BUT FEEL IT`S ENOUGH TO
BEGIN MENTIONING. 47
&&
.PREV DISCUSSION... /ISSUED 1145 AM CDT SAT APR 18 2015/
A STATIONARY FRONT WAS LOCATED JUST OFFSHORE ALONG THE COAST. THE
AIRMASS ALONG ABOUT A TWO-TIER COUNTY WIDTH ALONG THE COAST WAS
FAIRLY MOIST. NAMBUFR MODEL SOUNDINGS SHOW INCREASING INSTABILITY
DURING THE AFTERNOON WITH HEATING AND AS THE FRONTAL BOUNDARY
DRIFTS BACK INLAND. WATER VAPOR OVER THE PAST FEW HOURS SHOWED AN
APPROACHING SHORTWAVE TROUGH MOVING TOWARD THE AREA FROM THE
SOUTH. THE 06Z TEXAS TECH WRF AND 15Z HRRR BOTH FORECASTED BEST
CHANCES STARTING NEAR THE COAST BASICALLY ALONG AND EAST OF THE
HIGHWAY 59 CORRIDOR FROM MID AFTERNOON THROUGH MID EVENING.
ANOTHER UPPER LEVEL SHORTWAVE TROUGH WILL MOVE ACROSS SE TEXAS
LATE THIS EVENING FROM THE WEST. THIS MAY HELP GENERATE ADDITIONAL
SCATTERED STORMS DURING THE LATE EVENING AND INTO THE OVERNIGHT
PERIOD.
TWEAKED RAIN CHANCES MAINLY FOR TONIGHT AND ALSO TEMPERATURES FOR
TODAY. 40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 79 62 85 56 75 / 30 40 10 0 0
HOUSTON (IAH) 80 64 84 60 78 / 50 30 20 10 0
GALVESTON (GLS) 77 69 81 67 75 / 40 30 20 20 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1201 PM CDT SAT APR 18 2015
.UPDATE...
CONVECTION HAS BEEN A LITTLE SLOWER TO BEGIN THIS MORNING. HAVE
REDUCED POPS FOR THE NEXT COUPLE OF HOURS...ESPECIALLY ACROSS THE
EASTERN HALF OF THE CWA. SPC HAS UPDATED THE DAY ONE OUTLOOK AND
INCREASED OUR RISK TO ENHANCED. EXPECTING STRONG TO SEVERE STORMS
TO FORM LATER THIS AFTERNOON ALONG THE DRYLINE WHICH CURRENTLY
STRETCHES FROM AROUND CHILDRESS TO MIDLAND TO THE BIG BEND. THESE
STORMS WILL MOVE EASTWARD AND INTO OUR NORTHERN AREA LATE THIS
AFTERNOON OR EARLY EVENING. THE MAIN THREAT LOOKS TO BE LARGE HAIL
AND DAMAGING WINDS. THERE IS ALSO A LESSER THREAT FOR TORNADOES. WITH
ALL OF THE RAIN OVER THE PAST COUPLE OF DAYS LOCALLY HEAVY
RAINFALL IN STORMS WILL RUNOFF QUICKLY AND MAY CAUSE FLASH
FLOODING...BUT THIS IS NOT A WIDESPREAD THREAT.
&&
.PREV DISCUSSION... /ISSUED 611 AM CDT SAT APR 18 2015/
AVIATION...
CEILINGS ARE IFR/MVFR AROUND THE AREA AIRPORTS THIS MORNING AND
CONDITIONS SHOULD SLOWLY IMPROVE TO VFR BY EARLY AFTERNOON.
CONVECTION HAS DEVELOPED WEST OF KDRT AND WILL SHOW VCTS FOR THE
FIRST FEW HOURS OF THE VALID TAF PERIOD. CONFIDENCE REGARDING
CONVECTION CHANCES THIS AFTERNOON IS NOT VERY HIGH. THE MOST
LIKELY SCENARIO IS FOR THIS ELEVATED CONVECTION TO MOVE EAST THIS
MORNING AND THE ATMOSPHERE TO REENERGIZE BY THE LATE AFTERNOON
HOURS. THERE SHOULD BE A SURFACE CONVERGENCE ZONE DEVELOPING WEST
OF THE I-35 TAF SITES. THE MOST LIKELY TIME THESE WOULD BE TO THE
TERMINALS WOULD BE AROUND 22-03Z. WILL HANDLE THIS WITH A VCTS
FOR NOW. ADDITIONAL MVFR RESTRICTIONS ARE POSSIBLE TONIGHT...BUT
IFR IS NOT ANTICIPATED AS SLIGHTLY DRIER AIR MOVES INTO THE AREA.
HAMPSHIRE
PREV DISCUSSION... /ISSUED 401 AM CDT SAT APR 18 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
AN UPPER LEVEL STORM SYSTEM IS CENTERED ACROSS COLORADO EARLY THIS
MORNING. THIS SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST AND THEN
EAST THROUGH THE WEEKEND AND BECOMES AN OPEN WAVE LATE SUNDAY
AFTERNOON. SEVERAL SHORT WAVES ASSOCIATED WITH THE UPPER LEVEL
LOW ARE ANTICIPATED TO PUSH ACROSS THE AREA FOR THE NEXT 12 TO 18
HOURS AND ENHANCE STORM DEVELOPMENT LATE THIS MORNING THROUGH THE
EVENING HOURS. AT LOWER LEVELS...A PRE-FRONTAL TROUGH/DRY-LINE
WILL SERVE AS THE MAIN FOCUS AS STORMS FORM IN THE MOIST AND
WARM SECTOR. BY THIS AFTERNOON...DEWPOINT TEMPERATURES ARE
FORECAST TO REACH THE MID TO UPPER 60S WITH AREA SOUNDINGS
SUGGESTING ML CAPES OF 1500 TO 2500J/KG AND LI RANGING FROM -5 TO
-10 FOR LARGE TO EXTREME INSTABILITY. THEREFORE...ANY STORM THAT
DOES DEVELOP HAS THE POTENTIAL TO BECOME STRONG OR SEVERE. PER SPC
DAY 1 CONVECTIVE OUTLOOK...ALL OF SOUTH CENTRAL TEXAS WITH THE
EXCEPTION OF THE NORTHWEST PORTION OF VAL VERDE COUNTY...IS UNDER
A SLIGHT RISK OF SEVERE THUNDERSTORMS.
HIRES SOLUTIONS ARE HAVING DIFFICULTIES ON TIMING AND AREAS OF
STORM DEVELOPMENT INITIALLY. THE HRRR STARTS CONVECTION ACROSS THE
SOUTHERN COUNTIES AS AN MCS DEVELOPS ACROSS THE COASTAL PLAINS AND
MOVE TO THE EAST. THE TEXAS TECH IS MORE AGGRESSIVE ON FORMING
STORMS AHEAD OF THE DRY-LINE AS IT PUSHES TO THE EAST AND OVER THE
EDWARDS PLATEAU/HILL COUNTRY AREA. THE HRRR DOES DEVELOP
CONVECTION AHEAD OF THE DRY-LINE THIS AFTERNOON BUT NOWHERE NEAR
TEXAS TECH MODEL. THEREFORE...THE SHORT-TERM/FIRST PERIOD CONSISTS
ON A BLEND OF THE HRRR/TEXAS TECH SOLUTIONS. BY LATER THIS
EVENING...MID LEVEL WESTERLY WILL TAKE OVER AS THE UPPER LEVEL LOW
PUSHES TO THE EAST...MARKING THE END OF RAIN CHANCES THROUGH
MONDAY. WITH A WESTERLY FLOW IN PLACE FOR SUNDAY...EXPECT A NICE
WARMUP WITH HIGHS IN THE UPPER 80S AND LOWER 90S. CAN NOT RULE OUT
AN ISOLATED STORM ACROSS THE FAR EASTERN COUNTIES SUNDAY
AFTERNOON AS LINGERING INSTABILITY REMAINS. A BACK DOOR COLD FRONT
WILL PUSH ACROSS THE AREA SUNDAY EVENING TO COOL THE OVERNIGHT
TEMPS INTO THE 50S AREAWIDE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
A CLEAR NIGHT IS IN STORE FOR SUNDAY NIGHT WITH NORTHERLY WINDS
AND COOL TEMPERATURES FOLLOWED BY A PARTLY CLOUDY DAY ON MONDAY.
SOUTHERLY FLOW RETURNS TUESDAY AS WELL AS THE RAIN CHANCES FOR
SOUTH CENTRAL TEXAS. SEVERAL SHORT WAVES ARE EXPECTED TO PASS BY
AND TRIGGER SHOWERS AND STORMS THROUGH FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 81 61 89 57 76 / 40 40 - - -
AUSTIN BERGSTROM INTL AIRPORT 81 60 87 55 76 / 50 40 - - -
NEW BRAUNFELS MUNI AIRPORT 81 60 87 56 76 / 50 30 0 - -
BURNET MUNI AIRPORT 79 57 87 53 74 / 40 40 - - -
DEL RIO INTL AIRPORT 86 59 90 59 79 / 30 10 0 - 10
GEORGETOWN MUNI AIRPORT 79 59 87 54 74 / 40 40 10 - -
HONDO MUNI AIRPORT 82 59 88 57 78 / 40 20 0 - -
SAN MARCOS MUNI AIRPORT 81 61 86 56 75 / 50 40 0 - -
LA GRANGE - FAYETTE REGIONAL 80 63 86 57 75 / 50 40 20 10 10
SAN ANTONIO INTL AIRPORT 81 61 88 58 77 / 40 30 0 - -
STINSON MUNI AIRPORT 82 61 88 59 77 / 40 20 - - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...01
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1145 AM CDT SAT APR 18 2015
.DISCUSSION...
A STATIONARY FRONT WAS LOCATED JUST OFFSHORE ALONG THE COAST. THE
AIRMASS ALONG ABOUT A TWO-TIER COUNTY WIDTH ALONG THE COAST WAS
FAIRLY MOIST. NAMBUFR MODEL SOUNDINGS SHOW INCREASING INSTABILITY
DURING THE AFTERNOON WITH HEATING AND AS THE FRONTAL BOUNDARY
DRIFTS BACK INLAND. WATER VAPOR OVER THE PAST FEW HOURS SHOWED AN
APPROACHING SHORTWAVE TROUGH MOVING TOWARD THE AREA FROM THE
SOUTH. THE 06Z TEXAS TECH WRF AND 15Z HRRR BOTH FORECASTED BEST
CHANCES STARTING NEAR THE COAST BASICALLY ALONG AND EAST OF THE
HIGHWAY 59 CORRIDOR FROM MID AFTERNOON THROUGH MID EVENING.
ANOTHER UPPER LEVEL SHORTWAVE TROUGH WILL MOVE ACROSS SE TEXAS
LATE THIS EVENING FROM THE WEST. THIS MAY HELP GENERATE ADDITIONAL
SCATTERED STORMS DURING THE LATE EVENING AND INTO THE OVERNIGHT
PERIOD.
TWEAKED RAIN CHANCES MAINLY FOR TONIGHT AND ALSO TEMPERATURES FOR
TODAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 79 62 85 56 75 / 30 40 10 0 0
HOUSTON (IAH) 80 64 84 60 78 / 50 30 20 10 0
GALVESTON (GLS) 77 69 81 67 75 / 40 30 20 20 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...41
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
401 PM EDT SAT APR 18 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE OVER OUR AREA TODAY WILL MOVE EAST ALLOWING
A MOISTURE EASTERLY FLOW TO DEVELOP TONIGHT. A COMPLEX STORM SYSTEM
PASSING TO THE WEST WILL RESULT IN MORE WIDESPREAD RAIN...HEAVY AT
TIMES...SUNDAY INTO SUNDAY NIGHT BEFORE A COLD FRONT CROSSES THE
REGION WITH A CHANCE OF SHOWERS AND POTENTIALLY STRONG STORMS ON
MONDAY. DRY AND COOL CONDITIONS WILL PREVAIL FOR THE MIDDLE PART OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 300 PM EDT SATURDAY
WEAK LOW LEVEL CONVERGENCE JUST SOUTH OF OUR FORECAST AREA HAS
IGNITED A FEW SHOWERS AND ISOLATED STORMS. THE HRRR MODEL LIFTS THIS
BOUNDARY SLIGHTLY NORTH. THIS COMBINED WITH A WEAK UPSLOPE FLOW MAY
FIRE A FEW SHOWERS AND ISOLATED STORMS SOUTH OF HIGHWAY 58 THIS
AFTERNOON AND EARLY THIS EVENING...THEREFORE KEPT A SMALL CHANCE FOR
POPS IN THE FORECAST.
ALL THE MODELS ARE IN GOOD AGREEMENT ON DEVELOPING A STRONG LOW
LEVEL SOUTHEAST JET...TRANSPORTING MOISTURE INTO THE AREA OVERNIGHT.
A FEW GUSTS OVER 30KTS WILL BE POSSIBLE IN SOUTHEAST WV/CLINCH RIVER
VALLEY VA OVERNIGHT AND SUNDAY...BUT VALUES ARE BELOW GUIDANCE
CRITERIA.
PWATS INCREASE TO 2-3 STANDARD DEVIATIONS ABOVE AVERAGE BY SUNDAY
MORNING AND THROUGH MUCH OF THE DAY SUNDAY. MEANWHILE...A LARGE AREA
UVV LIFTS NORTH INTO OUR REGION TOWARD DAWN THEN EAST OVER ENTIRE
AREA ON SUNDAY. THIS IS IN ADVANCE OF A NEGATIVELY TILTED UPPER TROF
LIFTING THROUGH THE OHIO VALLEY SUNDAY WHICH ALSO GENERATES STRONG
UPPER DIFFLUENCE. AS A RESULT...EXPECT MODERATE TO HEAVY RAIN TO FALL
FOR SEVERAL HOURS...ESPECIALLY ALONG THE EAST SLOPES OF THE BLUE
RIDGE. MORE INFORMATION ABOUT THE FLOODING POTENTIAL FROM THIS
SYSTEM CAN BE FOUND IN THE HYDROLOGY SECTION. BOTTOM LINE...A FLOOD
WATCH WILL BE POSTED FOR THE NW NC MOUNTAINS/FOOTHILLS AND SOUTHERN
BLUE RIDGE OF VA. FUTURE SHIFTS MAY NEED TO EXPAND THIS NORTH AND
EAST...IF HIGHER QPF TRENDS CONTINUE.
CONTINUED TO GO BELOW GUIDANCE FOR HIGHS SUNDAY...WITH WEDGE IN
PLACE AND WIDESPREAD CLOUDS AND PRECIPITATION. IN FACT...MANY AREAS
IN THE WEDGE LIKELY SEE LITTLE...IF ANY...RECOVERY IN TEMPS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 335 PM EDT SATURDAY...
HEAVIER RAINFALL ASSOCIATED WITH NORTHEASTWARD MOVING STRONGLY
NEGATIVELY TILTED UPPER TROUGH AND ASSOCIATED WARM/WEDGE FRONT
WILL MOVE INTO THE PIEDMONT THROUGH 06Z MON...THEN EAST OF THE CWA
BETWEEN 06Z AND 12Z MON. ADDITIONAL RAINFALL OF 1/2 TO 3/4 INCH
DURING THIS TIME FRAME SHOULD BE CONFINED TO THE PIEDMONT. FLOOD
WATCH ENDS AT 04Z MON...WHICH SHOULD BE GOOD TIMING. MEANWHILE...A
BROAD UPPER TROUGH CONTINUES TO DEEPEN ACROSS THE GREAT LAKES WITH
UPPER FLOW REMAINING SOUTHWEST BEHIND THE AFOREMENTIONED UPPER
TROUGH. THE NEXT UPPER SHORT WAVE WILL BE APPROACHING THE WESTERN
AREAS BY DAYBREAK MONDAY WITH A STRONG COLD FRONT MOVING INTO THE
WESTERN TN/OH VALLEY. SCATTERED SHOWERS SHOULD DEVELOP ONCE AGAIN
ACROSS THE WESTERN MOUNTAINS IN ADVANCE OF THESE FEATURES. BY
AFTERNOON...MUCH OF THE CWA...ESPECIALLY EAST OF THE BLUE RIDGE
WILL BE SOLIDLY IN THE WARM SECTOR WITH TEMPERATURES ACROSS THE
PIEDMONT NEAR 80 DEGREES AND DEWPOINTS NEAR 60. A 6-HOUR WINDOW OF
SUBSTANTIAL CAPE IN EXCESS OF 1000 J/KG...BULK 0-6KM SHEAR OF
20-30KTS...LIS TO -6 ALONG THE VA/NC BORDER...AND SIG SVR PARMS
GREATER THAN 20000 COMBINED WITH STRONG PVA AND YET ANOTHER
NEGATIVELY TILTED SHORT WAVE STRONGLY SUPPORT THE SLIGHT RISK
OUTLOOK FROM SPC EAST OF THE BLUE RIDGE MON AFTERNOON...WITH THE
MARGINAL RISK FURTHER WEST INTO THE MOUNTAINS. MAIN CONCERNS WILL
BE THUNDERSTORM WIND GUSTS AND HAIL WITH COLD AIR ALOFT ADVECTING
INTO THE REGION. A FEW MORE DISCRETE CELLS COULD DEVELOP EAST OF
THE FRONT ACROSS THE PIEDMONT IF MAXIMUM INSTABILITY/HEATING IS
REALIZED. THE SEVERE THREAT WILL END QUICKLY FROM WEST TO EAST
AFT 00Z AS THE THERMODYNAMICS WANE QUICKLY AND THE UPPER SUPPORT
SHIFTS NORTHEAST OF THE REGION. RAINFALL WILL NOT BE A CONCERN
WITH THIS SECOND EVENT AS ACTIVITY WILL BE BRIEF AND
SCATTERED...BUT A QUICK 1/2 INCH OF RAIN MAY OCCUR IN AREAS WITH
HEAVIER SHOWERS/THUNDERSTORMS. SCATTERED UPSLOPE RAIN SHOWERS
COULD PERSIST ACROSS THE MOUNTAINS INTO TUESDAY...BUT NO
SIGNIFICANT DYNAMICS ARE FORESEEN WITHIN THIS TIME FRAME.
UNSEASONABLY WARM TEMPERATURES MONDAY WILL GIVE WAY TO MUCH COOLER
CONDITIONS ACROSS THE MOUNTAINS TUESDAY WITH VARIABLE CLOUDS AND A
FEW SHOWERS...BUT DOWNSLOPE PIEDMONT AREAS SHOULD STILL BE CLOSE
TO 70 EVEN TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 350 PM EDT SATURDAY...
MODELS IN BETTER AGREEMENT TODAY ON A DEEP AND BROAD UPPER LOW
CENTERED ACROSS THE EASTERN GREAT LAKES DOMINATING THE WEATHER
THROUGH MOST OF THE REMAINDER OF THE WORK WEEK. THIS WILL LEAVE
UNSETTLED CONDITIONS ACROSS THE MOUNTAINS...SOMEWHAT LESS SO
ACROSS THE PIEDMONT. THE ECMWF HAS COME INTO BETTER AGREEMENT WITH
THE GFS NOW ON A DISTURBANCE ROTATING THROUGH THE BOTTOM OF THE
UPPER TROUGH WEDNESDAY...BRINGING A BETTER THREAT OF SHOWERS TO
THE REGION. THUS...HAVE INCREASED POPS IN ACCORDANCE WITH THE
BETTER MODEL AGREEMENT AND SURROUNDING OFFICES. HAVE NOT
INTRODUCED THUNDER AT THIS POINT...BUT COULD NOT TOTALLY RULE OUT
SOME THUNDER BECAUSE OF RATHER COLD AIR ALOFT. FOLLOWING THIS
DISTURBANCE COMES THE BONAFIDE COLDER AIR WHICH PROMISES TO PUSH
850MB TEMPS DOWN TO 0C OR BELOW FOR MUCH OF THE REMAINDER OF THE
WEEK ACROSS THE NORTHERN AREAS. THE UPPER TROUGH GRADUALLY SHIFTS
MORE TOWARD THE MID-ATLANTIC LATE IN THE PERIOD...STRENGTHENING
THE NORTHWEST FLOW ACROSS THE REGION...AND ALLOWING 850MB TEMPS TO
BOTTOM OUT ACROSS THE NORTH AROUND -5C BY SATURDAY. THIS PATTERN
WILL CONTINUE TO RESULT IN A SIGNIFICANT TEMPERATURE DIFFERENCE
FROM THE WESTERN MOUNTAINS WITH CLOUDS AND VARIABLE
CLOUDS/SCATTERED SHOWERS AND MORE SUNNY/DOWNSLOPE NORTHWEST FLOW
ACROSS THE PIEDMONT. OVERALL...TEMPERATURES SHOULD AVERAGE BELOW
NORMAL THROUGH THE PERIOD...PERHAPS MUCH BELOW IN THE WEST. MEXMOS
SHOWS SEVERAL DAYS WITH HIGHS ONLY IN THE 50S/60S WEST AND LOWS IN
THE UPPER 30S TO LOWER 40S. WIND AND CLOUDS SHOULD PREVENT ANY
FROST/FREEZE CONCERN AT THIS POINT.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
AS OF 120 PM EDT SATURDAY...
VFR CONDITIONS WERE NOTED AT ALL THE TAF SITES EARLY THIS
AFTERNOON...BUT FLYING CONDITIONS ARE FORECAST TO DETERIORATE
DURING THE OVERNIGHT HOURS/EARLY MORNING SUNDAY.
FOR THE REMINDER OF TODAY...WEAK CONVERGENCE AND UPSLOPE MAY
GENERATE ISOLD SHWRS OR TSTORMS THIS AFTERNOON...ESPECIALLY NEAR
BLUE RIDGE ALONG OR SOUTH OF VA/NC BORDER...BUT PROBABILITY IS TOO
LOW TO INCLUDE IN ANY OF THE TAFS AT THIS TIME.
MODELS HAVE BEEN CONSISTENT WITH CLOUDS AND THEN RAIN WILL SPREAD
INTO THE AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. EXPECT CEILINGS
TO LOWER TO MVFR AFTER 08Z. HIGHEST CONFIDENCE IN MVFR CEILINGS
IS AT KBCB AFTER 08Z/2AM.
A STRONG SOUTHEAST LOW LEVEL JET WILL DEVELOP JUST AFTER
MIDNIGHT WHICH MAY BRING WIND GUSTS TO 30 KTS AT KLBF EARLY
SUNDAY AND CONTINUE THROUGH 18Z. WITH A WEDGE OF HIGH PRESSURE IN
PLACE ALONG AND EAST OF THE BLUE RIDGE...THESE STRONG WINDS ARE
NOT EXPECTED TO REACH THE SURFACE AND KBCB AND KLWB...BUT WILL
CREATE POTENTIALLY HAZARDOUS LOW LEVEL WIND SHEAR CONDITIONS. KROA
WILL BE NEED TO BE CAREFULLY MONITORED TO POSSIBLE INCLUSION OF LL
WIND SHEAR.
CIGS WILL CONTINUE TO DROP AND RAIN WILL BECOME WIDESPREAD DURING
THE DAY SUNDAY...AS A STRONG UPSLOPE FLOW TRANSPORTS ABUNDANT
MOISTURE INTO THE REGION NORTH OF A NEARLY STATIONARY FRONT.
WIDESPREAD IFR CONDITIONS ARE FORECAST IN THE MOUNTAINS AND
FOOTHILLS...WITH MVFR CIGS AT KLYH AND KDAN LIKELY DETERIORATING
AFTER 18Z SUNDAY WHEN THE HEAVIEST PRECIPITATION MOVES ARRIVES.
EXTENDED AVIATION...
A COMPLEX STORM SYSTEM WILL BEGIN TO AFFECT THE REGION SUNDAY WITH
A WARM FRONT BRINGING WIDESPREAD MVFR/IFR CONDITIONS IN RAIN
INTO SUNDAY NIGHT.
THIS WILL BE FOLLOWED BY ANOTHER COLD FRONT MONDAY. THIS IS LIKELY
TO KEEP PERIODS OF MVFR IN PLACE UNTIL THE FRONT POSSIBLY CLEARS
THE REGION.
VFR RETURNS LATER MONDAY NIGHT AND TUESDAY WITH HIGH
PRESSURE BUILDING IN BEHIND THE FRONT WITH A DRIER AIRMASS.
THEN THE NEXT CHANCE OF MVFR CONDITIONS AND PRECIPITATION WILL BE
IN THE MOUNTAINS ON WEDNESDAY.
.HYDROLOGY...
AS OF 330 PM EDT SATURDAY...
ANTECEDENT CONDITIONS ARE STILL MOIST ACROSS THE NW NC
MOUNTAINS/FOOTHILLS INTO THE SOUTHERN BLUE RIDGE OF VA WITH THE
PERCENT OF NORMAL PRECIP OVER THE PAST WEEK EXCEEDING OVER 150%.
THIS ALSO IS SHOWN IN RIVER STAGE LEVELS ACROSS THIS REGION FROM
THE USGS WITH STREAM LEVELS IN MANY LOCATIONS RUNNING GREATER THAN
THE 75TH PERCENTILE. WITH 6 HOUR FLASH FLOOD GUIDANCE VALUES BELOW
3 INCHES IN THE REGION...AND FORECAST PW VALUES 2-3 STANDARD
DEVIATIONS ABOVE NORMAL...EXPECT FLOODING OF CREEKS AND STREAMS.
WHILE THE SREF MODEL ENSEMBLE RIVER FORECAST ONLY IS FORECASTING A
SMALL CHANCE FOR RIVERS TO REACH ACTION STAGE...WOULD NOT BE
SURPRISED TO SEE A FEW SITES REACH MINOR FLOODING CONSIDERING THE
MODEL TRENDS OF INCREASING QPF WITH EACH RUN.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLOOD WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
VAZ015>017-032.
NC...FLOOD WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
NCZ001>003-018>020.
WV...NONE.
&&
$$
SYNOPSIS...PH
NEAR TERM...PH
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...AMS/PH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1128 AM CDT SAT APR 18 2015
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...
ISSUED AT 407 AM CDT SAT APR 18 2015
AFTER FURTHER COORDINATION WITH ARX AND THE DNR...WILL ISSUE A RED
FLAG WARNING FOR WOOD COUNTY. THE COMBO OF HUMIDITIES FALLING NEAR
20 PCT THIS AFTERNOON...MAX TEMPS IN THE 60S...WIND SPEEDS OF 10
TO 20 MPH...AND DRY FUELS WILL LEAD TO A CRITICAL FIRE WEATHER DAY
THERE. THIS RED FLAG WARNING WILL TARGET THE PINE COUNTRY OF
CENTRAL WISCONSIN.
ADDITIONALLY...THE COLD FRONT HAS JUST PASSED OVER GREEN BAY.
WINDS HAVE SHIFTED TO THE NORTH AND ARE GUSTING TO 22 KNOTS AT THE
GRB AIRPORT. SOME GUSTS UP TO 25 KNOTS OVER THE BAY ARE ALSO OCCURRING.
&&
.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A FAIRLY
POTENT COLD FRONT DROPPING SOUTH OVER FAR N-C WISCONSIN AND THE
CENTRAL UPPER PENINSULA. NORTH WINDS BEHIND THE FRONT COMBINED WITH
IMPRESSIVE PRESSURE RISES ARE CONTRIBUTING TO WIND GUSTS OVER 30 KTS
OVER LAKE SUPERIOR. AS THE FRONT MOVES ACROSS NORTHERN WISCONSIN
EARLY THIS MORNING...EXPECT NORTH WINDS TO STRENGTHEN AND BECOME
GUSTY FOR PERIOD. ELSEWHERE...UPPER LEVEL LOW PRESSURE CONTINUES TO
SPIN OVER THE CENTRAL ROCKIES AND PRODUCE SHOWERS AND THUNDERSTORMS
ACROSS THE CENTRAL GREAT PLAINS. FORECAST CONCERNS INCLUDE FIRE
WEATHER PARAMETERS TODAY...AND PRECIP CHANCES ON SUNDAY.
TODAY...THE DRY COLD FRONT WILL DROP SOUTH ACROSS THE REST OF
NORTHERN WISCONSIN EARLY THIS MORNING AND CENTRAL WISCONSIN BY
MID-MORNING. BEHIND THE FRONT...THE MODELS ARE STILL DEPICTING VERY
DRY AIR TO MOVE INTO NORTH-CENTRAL TO EAST-CENTRAL WISCONSIN TODAY.
THOUGH NORTHEAST WINDS OFF LAKE MICHIGAN WILL HELP MODERATE THE DRY
AIR OVER EASTERN WISCONSIN...MODEST WIND SPEEDS SHOULD BE ABLE TO TAP INTO
THIS VERY DRY AIR JUST ABOVE THE INVERSION...AROUND 900MB. SO WAS
AGGRESSIVE IN DROPPING HUMIDITIES TODAY...WHICH SHOULD FALL INTO THE
TEENS OVER N-C WISCONSIN AND TO AROUND 25 PCT OVER CENTRAL
WISCONSIN. EAST WINDS WILL ALSO BE APPROACHING CRITICALLY SUSTAINED
SPEEDS OVER CENTRAL WISCONSIN THIS AFTERNOON. STILL WAITING FOR A
FINAL DECISION FROM THE DNR CONCERNING A RED FLAG WARNING...WHICH SHOULD
HAVE BY 5 AM. OTHERWISE...WILL SEE A SUNNY AND COOLER DAY. HIGHS
IN THE LOW TO MID 60S AWAY FROM LAKE MICHIGAN.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS THE CENTRAL ROCKIES
UPPER LOW MOVES ACROSS THE CENTRAL PLAINS...WHILE A NORTHERN STREAM
WAVE DIGS OVER THE NORTHERN PLAINS. AS CLOUDS THICKEN AND
LOWER...WINDS BELOW 900MB WILL REMAIN OUT OF THE SOUTHEAST AND
CONTINUE TO ADVECT VERY DRY AIR OVER THE REGION. THIS DRY AIR WILL
HAVE TO BE OVERCOME...AND THIS MAY NOT OCCUR UNTIL LATE IN THE NIGHT
OVER THE WEST. WILL MODIFY PRECIP CHANCES SLIGHTLY TO REFLECT THIS.
LOWS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTHWEST.
SUNDAY...MID-LEVEL HEIGHT FALLS WILL CONTINUE TO ADVANCE INTO THE
WESTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE INTO
WESTERN WISCONSIN DURING THE AFTERNOON...WHILE A SOUTHERN STREAM LOW
SWINGS NE TOWARDS THE SOUTHERN TIP OF LAKE MICHIGAN. FORCING WILL
IMPROVE THROUGH THE DAY AHEAD OF THESE FEATURES...THOUGH THE LEAD BAND OF
LIGHT RAIN MAY DECAY DURING THE MORNING AS A RESULT OF THE DRY LOW
LEVEL FLOW. THEN A SECOND ROUND OF PRECIP MAY TRY TO MOVE INTO THE
AREA WITH THE APPROACHING LOW PRESSURE SYSTEMS. TEMPS ARE DIFFICULT
BECAUSE OF THE PRECIP POTENTIAL...AMPLE CLOUD COVER...AND EAST
WINDS. HAVE DROPPED TEMPS SOME SINCE TEMPS DO NOT TYPICALLY RISE
WELL WHEN THERE IS CLOUD COVER AND EAST WINDS. PRECIP WILL ALSO
LIKELY HOLD TEMPS BACK OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. SO
WENT WITH HIGHS RANGING FROM THE MID 50S NORTH TO LOW 60S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 330 AM CDT SAT APR 18 2015
500MB TROUGH WILL EVOLVE INTO A CLOSED UPPER LOW OVER THE WESTERN
GREAT LAKES REGION EARLY NEXT WEEK...THEN MEANDER ACROSS EASTERN
CANADA AND THE GREAT LAKES REGION THROUGH THE END OF NEXT WEEK.
THIS WILL LEAD TO COOL AND UNSETTLED CONDITIONS...ALONG WITH A
CHANCE OF SNOW LATE AT NIGHT AND EARLY MORNING HOURS.
RAINFALL TOTALS STILL PROBLEMATIC SUNDAY NIGHT AS TWO SEPARATE
SYSTEMS WILL BRING RAIN TO THE AREA. NORTHERN STREAM SYSTEM WILL
BRING RAIN TO THE WESTERN HALF OF THE STATE...MEANWHILE A FAIRLY
POTENT LOW PRESSURE SYSTEM WILL MOVE NORTHEAST INTO THE GREAT
LAKES REGION SUNDAY NIGHT. STILL A LOT OF QUESTIONS ON TRACK OF
SYSTEM DUE TO CLOSING UPPER LOW NORTHWEST OF THE STATE. MODEL QPF
WOULD SUGGEST THAT MUCH NEEDED RAIN WOULD FALL ACROSS THE REGION.
MAIN QUESTION IS WHERE AXIS OF HEAVIER RAIN WOULD FALL. MODEL
RUN TO RUN CONTINUITY HAS NOT BEEN CONSISTENT...THUS LOW CONFIDENCE
IN THE RAINFALL AMOUNT FORECAST. MONDAY IS NOT MUCH CLEARER AS SOME
OF THE MODELS BRING DRY SLOT ACROSS THE AREA WITH A SIGNIFICANT DOWNWARD
TREND IN RAINFALL AMOUNTS. THE ECMWF/CANADIAN DO NOT SHARE THIS TREND
WITH THE WRF/GFS...THUS WILL KEEP SCATTERED DEPICTION/WORDING IN
THE FORECAST.
AS UPPER LOW CLOSES MONDAY NIGHT THROUGH WEDNESDAY...COOL CYCLONIC FLOW
AND WEAK DISTURBANCES MOVING THROUGH THE MEAN FLOW WILL BRING
CHANCES OF RAIN AND SNOW SHOWERS DEPENDING ON LOCATION AND TIMING
OF THE DAY. AT SOME POINT...THERE COULD BE A MINOR ACCUMULATION OF
SNOW ACROSS THE NORTH. SOME MODERATION IN TEMPERATURES IS EXPECTED BY
THE END OF THE WEEK AS THE UPPER LOW GRADUALLY SHIFTS EAST OF THE AREA.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1102 AM CDT SAT APR 18 2015
VFR CONDITIONS EXPECTED THROUGH THIS AFTERNOON. GUSTY ENE WINDS TO
CONTINUE BEFORE DIMINISHING THIS EVENING...WITH THE GUSTIEST WINDS
IN EASTERN TAF SITES.
DRY CONDITIONS WILL HOLD THROUGH THE NIGHT...WITH INCREASING VFR
CLOUD COVER FROM SW TO NE THROUGH THE NIGHT. LLWS THROUGH ABOUT
1500FT WILL DEVELOP AFTER MIDNIGHT...AND THEN DIMINISH SUNDAY
MORNING AS WINDS MIX AGAIN.
VFR CIGS WILL STICK AROUND SUNDAY...WITH RAIN SHOWERS POSSIBLE IN
NORTH-CENTRAL WISCONSIN AFTER DAYBREAK AS A LOW PRESSURE SYSTEM
LIFTS TO THE NORTH AND WEST OF THE STATE...WITH ONLY VERY LIGHT
RAIN AND PCPN EXPECTED. EASTERN TAF SITES SHOULD STAY DRY UNTIL AT
LEAST MIDDAY IF NOT MOST OF SUNDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR WIZ035.
&&
$$
UPDATE.........MPC
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......ALLEN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
243 PM MDT SAT APR 18 2015
.UPDATE...
ISSUED AT 239 PM MDT SAT APR 18 2015
TORNADO WATCH ISSUED FOR CHEYENNE COUNTY AND MORRILL COUNTY IN THE
SOUTHERN NEBRASKA PANHANDLE UNTIL 8 PM. BASED ON CURRENT MESOSCALE
ANALYSIS...THE MAIN THREATS ARE MARGINAL SEVERE HAIL AND FUNNEL
CLOUDS THIS AFTERNOON...BUT AN ISOLATED BRIEF TORNADO IS NOT OUT
OF THE QUESTION IN THE WATCH COUNTIES. MOST LIKELY THE BOUNDARY
LAYER WILL STABILIZE OVER THE NEXT SEVERAL HOURS AS COLD OUTFLOW
FROM SHOWERS AND THUNDERSTORMS SPREAD ACROSS THE AREA...ENDING
ANY THREAT FOR TORNADOS.
UPDATE ISSUED AT 1135 AM MDT SAT APR 18 2015
ADJUSTED WINTER WEATHER HEADLINES FOR THE BAND OF HEAVY SNOW WHICH
IS EXPECTED TO CONTINUE OVER NORTHERN ALBANY COUNTY AND
EASTERN/CENTRAL CARBON COUNTY TODAY. ADDED THE ARLINGTON ZONE TO
THE WARNING BASE ON LATEST GFS AND NAM SHOWING HEAVY PRECIPITATION
ACROSS THIS AREA THROUGH EARLY THIS EVENING. LATEST RADAR SHOWING
THE BAND OF HEAVY TROWAL PRECIPITATION SETTING UP AT THIS TIME AND
SURFACE OBS AND WEB CAMS VERIFY THE HEAVY SNOW. MODEL SURFACE
TEMPERATURES AND MOS GUIDANCE MOST LIKELY TOO WARM AROUND
ARLINGTON GIVEN WHAT WILL BE HEAVY PRECIPITATION. EAST AND WEST OF
THIS PRECIPITATION BAND...TEMPERATURES WILL WARM AS EXPECTED.
IMPACTS ON ROADS IS A BIT OF A QUESTION WITH TEMPERATURES NEAR
FREEZING AND HIGH SUN ANGLE THAT MAY BE ABLE TO MELT MUCH OF THE
SNOW...EVEN WITHIN THE HEAVY BAND. REGARDLESS ROADS WILL AT LEAST
BE SLUSHY AT TIMES...IF NOT COMPLETELY SNOW COVERED. MOST SNOW
ACCUMULATIONS WILL BE ON ELEVATED SURFACES AND OVER CURRENT SNOW
COVER.
WINTER WEATHER HEADLINES HAVE BEEN CANCELLED FOR THE SOUTHERN
LARAMIE RANGE AND FOOTHILLS WITH THE BAND OF SNOW SETTING UP WEST
OF THE THIS AREA. THERE IS THE POTENTIAL FOR SOME SNOW SHOWERS
THIS AFTERNOON. AS THE TROWAL SHIFTS EAST THIS EVENING THERE WILL
LIKELY BE A PERIOD OF SNOW OVER THE SOUTHERN LARAMIE RANGE BUT
ACCUMULATIONS WILL BE MINIMAL...MAYBE AN INCH OR TWO OF NEW
ACCUMULATIONS.
UPDATE ISSUED AT 1009 AM MDT SAT APR 18 2015
ADJUSTED POPS SLIGHTLY TO REFLECT THE POSITION OF THE TROWAL THIS
MORNING. THE TROWAL WHICH IS VERY DISTINGUISHABLE ON SATELLITE AND
RADAR WILL MOVE SLIGHTLY WESTWARD THROUGH EARLY AFTERNOON. AT THAT
POINT IT WILL STALL AND THEN SHIFT EAST INTO THIS EVENING AS A
NORTHERN STREAM KICKER PUSHES THE CLOSED UPPER LOW INTO THE
PLAINS.
LOWERED TEMPERATURES ACROSS THE WEST TODAY AS TROWAL PRECIPITATION
WILL HOLD TEMPERATURES DOWN...KEEPING MOST PRECIPITATION WEST OF
THE LARAMIE RANGE AS SNOW BUT SOME PLACES WILL MIX WITH OR CHANGE
TO RAIN. WILL KEEP AN EYE ON THINGS BUT MAY NEED TO LOWER
TEMPERATURES IN THE WEST A BIT MORE. LARAMIE SHOULD SEE SNOW
THROUGH THE DAY WITH SEVERAL MORE INCHES OF SNOWFALL. WITH
TEMPERATURES NEAR FREEZING AROUND LARAMIE AND THE RELATIVELY HIGH
APRIL SUN ANGLE...NOT MUCH SNOW WILL ACCUMULATE ON ROADS WAYS WITH
WET TO SLUSHY ROADS EXPECTED.
EAST OF THE LARAMIE RANGE THERE IS THE POTENTIAL FOR THUNDERSTORMS
THIS AFTERNOON. MODELS SHOWING 500-1000 J/KG OF MOST UNSTABLE
CAPE. SHEAR VALUES ARE NOT IMPRESSIVE...BUT GIVEN THE COLD NATURE
OF THIS SYSTEM...IT IS LIKELY THERE WILL BE SOME SMALL HAIL TODAY
AND WITH LOW FREEZING LEVELS...MARGINAL SEVERE HAIL NOT OUT OF THE
QUESTION WITH ANY STRONGER UPDRAFTS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT SAT APR 18 2015
TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL
COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL
MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING
WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT
UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE
OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM
WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY
WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL
IMPACTS TO TRAVEL.
TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM
SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH
DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES.
SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT
AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR
NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY
CONDITIONS ELSEWHERE.
SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES
PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR
SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 415 AM MDT SAT APR 18 2015N
THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END
POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE
ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD
BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY
RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN
COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF
BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES
AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF
THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON
THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS.
WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A
SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM
ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE
BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT
WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE
AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS
LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH SUNDAY MORNING)
THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF THE
LARAMIE RANGE AND MOVING SLIGHTLY WESTWARD. IFR CONDITIONS AND LIGHT
SNOW WILL CONTINUE BETWEEN KRWL AND KLAR THIS AFTERNOON...WITH MVFR
CONDITIONS EXPECTED AT KRWL...AND IFR CONDITIONS AT KLAR. IFR
CONDITIONS DUE TO LOW CIGS WILL CONTINUE AT KCYS...BUT CONDITIONS
SHOULD IMPROVE A BIT THROUGH THE AFTERNOON AS SHOWERS BEGIN TO
DEVELOP TO THE SOUTH. A COLD FRONT WILL PUSH ACROSS THE PLAINS BY
LATE THIS EVENING (AFTER 03Z) WITH BREEZY NORTH WINDS EXPECTED.
&&
.FIRE WEATHER...
ISSUED AT 402 AM MDT SAT APR 18 2015
NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD
PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ110-114.
WINTER WEATHER ADVISORY UNTIL 9 PM MDT THIS EVENING FOR WYZ103-
105-106-112-113-115.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...RUBIN
LONG TERM...ZF
AVIATION...TJT
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1136 AM MDT SAT APR 18 2015
.UPDATE...
ISSUED AT 1135 AM MDT SAT APR 18 2015
ADJUSTED WINTER WEATHER HEADLINES FOR THE BAND OF HEAVY SNOW WHICH
IS EXPECTED TO CONTINUE OVER NORTHERN ALBANY COUNTY AND
EASTERN/CENTRAL CARBON COUNTY TODAY. ADDED THE ARLINGTON ZONE TO
THE WARNING BASE ON LATEST GFS AND NAM SHOWING HEAVY PRECIPITATION
ACROSS THIS AREA THROUGH EARLY THIS EVENING. LATEST RADAR SHOWING
THE BAND OF HEAVY TROWAL PRECIPITATION SETTING UP AT THIS TIME AND
SURFACE OBS AND WEB CAMS VERIFY THE HEAVY SNOW. MODEL SURFACE
TEMPERATURES AND MOS GUIDANCE MOST LIKELY TOO WARM AROUND
ARLINGTON GIVEN WHAT WILL BE HEAVY PRECIPITATION. EAST AND WEST OF
THIS PRECIPITATION BAND...TEMPERATURES WILL WARM AS EXPECTED.
IMPACTS ON ROADS IS A BIT OF A QUESTION WITH TEMPERATURES NEAR
FREEZING AND HIGH SUN ANGLE THAT MAY BE ABLE TO MELT MUCH OF THE
SNOW...EVEN WITHIN THE HEAVY BAND. REGARDLESS ROADS WILL AT LEAST
BE SLUSHY AT TIMES...IF NOT COMPLETELY SNOW COVERED. MOST SNOW
ACCUMULATIONS WILL BE ON ELEVATED SURFACES AND OVER CURRENT SNOW
COVER.
WINTER WEATHER HEADLINES HAVE BEEN CANCELLED FOR THE SOUTHERN
LARAMIE RANGE AND FOOTHILLS WITH THE BAND OF SNOW SETTING UP WEST
OF THE THIS AREA. THERE IS THE POTENTIAL FOR SOME SNOW SHOWERS
THIS AFTERNOON. AS THE TROWAL SHIFTS EAST THIS EVENING THERE WILL
LIKELY BE A PERIOD OF SNOW OVER THE SOUTHERN LARAMIE RANGE BUT
ACCUMULATIONS WILL BE MINIMAL...MAYBE AN INCH OR TWO OF NEW
ACCUMULATIONS.
UPDATE ISSUED AT 1009 AM MDT SAT APR 18 2015
ADJUSTED POPS SLIGHTLY TO REFLECT THE POSITION OF THE TROWAL THIS
MORNING. THE TROWAL WHICH IS VERY DISTINGUISHABLE ON SATELLITE AND
RADAR WILL MOVE SLIGHTLY WESTWARD THROUGH EARLY AFTERNOON. AT THAT
POINT IT WILL STALL AND THEN SHIFT EAST INTO THIS EVENING AS A
NORTHERN STREAM KICKER PUSHES THE CLOSED UPPER LOW INTO THE
PLAINS.
LOWERED TEMPERATURES ACROSS THE WEST TODAY AS TROWAL PRECIPITATION
WILL HOLD TEMPERATURES DOWN...KEEPING MOST PRECIPITATION WEST OF
THE LARAMIE RANGE AS SNOW BUT SOME PLACES WILL MIX WITH OR CHANGE
TO RAIN. WILL KEEP AN EYE ON THINGS BUT MAY NEED TO LOWER
TEMPERATURES IN THE WEST A BIT MORE. LARAMIE SHOULD SEE SNOW
THROUGH THE DAY WITH SEVERAL MORE INCHES OF SNOWFALL. WITH
TEMPERATURES NEAR FREEZING AROUND LARAMIE AND THE RELATIVELY HIGH
APRIL SUN ANGLE...NOT MUCH SNOW WILL ACCUMULATE ON ROADS WAYS WITH
WET TO SLUSHY ROADS EXPECTED.
EAST OF THE LARAMIE RANGE THERE IS THE POTENTIAL FOR THUNDERSTORMS
THIS AFTERNOON. MODELS SHOWING 500-1000 J/KG OF MOST UNSTABLE
CAPE. SHEAR VALUES ARE NOT IMPRESSIVE...BUT GIVEN THE COLD NATURE
OF THIS SYSTEM...IT IS LIKELY THERE WILL BE SOME SMALL HAIL TODAY
AND WITH LOW FREEZING LEVELS...MARGINAL SEVERE HAIL NOT OUT OF THE
QUESTION WITH ANY STRONGER UPDRAFTS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT SAT APR 18 2015
TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL
COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL
MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING
WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT
UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE
OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM
WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY
WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL
IMPACTS TO TRAVEL.
TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM
SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH
DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES.
SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT
AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR
NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY
CONDITIONS ELSEWHERE.
SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES
PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR
SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 415 AM MDT SAT APR 18 2015N
THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END
POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE
ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD
BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY
RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN
COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF
BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES
AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF
THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON
THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS.
WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A
SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM
ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE
BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT
WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE
AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS
LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH SUNDAY MORNING)
THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF THE
LARAMIE RANGE AND MOVING SLIGHTLY WESTWARD. IFR CONDITIONS AND LIGHT
SNOW WILL CONTINUE BETWEEN KRWL AND KLAR THIS AFTERNOON...WITH MVFR
CONDITIONS EXPECTED AT KRWL...AND IFR CONDITIONS AT KLAR. IFR
CONDITIONS DUE TO LOW CIGS WILL CONTINUE AT KCYS...BUT CONDITIONS
SHOULD IMPROVE A BIT THROUGH THE AFTERNOON AS SHOWERS BEGIN TO
DEVELOP TO THE SOUTH. A COLD FRONT WILL PUSH ACROSS THE PLAINS BY
LATE THIS EVENING (AFTER 03Z) WITH BREEZY NORTH WINDS EXPECTED.
&&
.FIRE WEATHER...
ISSUED AT 402 AM MDT SAT APR 18 2015
NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD
PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ110-114.
WINTER WEATHER ADVISORY UNTIL 9 PM MDT THIS EVENING FOR WYZ103-
105-106-112-113-115.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...RUBIN
LONG TERM...ZF
AVIATION...TJT
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1010 AM MDT SAT APR 18 2015
.UPDATE...
ISSUED AT 1009 AM MDT SAT APR 18 2015
ADJUSTED POPS SLIGHTLY TO REFLECT THE POSITION OF THE TROWAL THIS
MORNING. THE TROWAL WHICH IS VERY DISTINGUISHABLE ON SATELLITE AND
RADAR WILL MOVE SLIGHTLY WESTWARD THROUGH EARLY AFTERNOON. AT THAT
POINT IT WILL STALL AND THEN SHIFT EAST INTO THIS EVENING AS A
NORTHERN STREAM KICKER PUSHES THE CLOSED UPPER LOW INTO THE
PLAINS.
LOWERED TEMPERATURES ACROSS THE WEST TODAY AS TROWAL PRECIPITATION
WILL HOLD TEMPERATURES DOWN...KEEPING MOST PRECIPITATION WEST OF
THE LARAMIE RANGE AS SNOW BUT SOME PLACES WILL MIX WITH OR CHANGE
TO RAIN. WILL KEEP AN EYE ON THINGS BUT MAY NEED TO LOWER
TEMPERATURES IN THE WEST A BIT MORE. LARAMIE SHOULD SEE SNOW
THROUGH THE DAY WITH SEVERAL MORE INCHES OF SNOWFALL. WITH
TEMPERATURES NEAR FREEZING AROUND LARAMIE AND THE RELATIVELY HIGH
APRIL SUN ANGLE...NOT MUCH SNOW WILL ACCUMULATE ON ROADS WAYS WITH
WET TO SLUSHY ROADS EXPECTED.
EAST OF THE LARAMIE RANGE THERE IS THE POTENTIAL FOR THUNDERSTORMS
THIS AFTERNOON. MODELS SHOWING 500-1000 J/KG OF MOST UNSTABLE
CAPE. SHEAR VALUES ARE NOT IMPRESSIVE...BUT GIVEN THE COLD NATURE
OF THIS SYSTEM...IT IS LIKELY THERE WILL BE SOME SMALL HAIL TODAY
AND WITH LOW FREEZING LEVELS...MARGINAL SEVERE HAIL NOT OUT OF THE
QUESTION WITH ANY STRONGER UPDRATS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 415 AM MDT SAT APR 18 2015
TODAY...SLOW MOVING CLOSED UPPER LOW PROGGED TO MOVE FROM CENTRAL
COLORADO THIS MORNING TO EAST CENTRAL COLORADO BY DINNER TIME. ALL
MODELS INCLUDING THE HRRR SHOW A BAND OF PRECIPITATION SWINGING
WESTWARD ACROSS OUR COUNTIES THIS MORNING AND AFTERNOON WITH DECENT
UPWARD VERTICAL MOTION AND QUASIGEOSTROPHIC FORCING...THUS HAVE
OPTED TO EXTEND OUR WINTER WEATHER ADVISORIES AND WINTER STORM
WARNINGS THROUGH MIDDAY...WHILE DROPPING CHEYENNE FROM THE ADVISORY
WITH TEMPERATURES LIKELY REMAINING ABOVE FREEZING AND THUS MINIMAL
IMPACTS TO TRAVEL.
TONIGHT...FINALLY...THE UPPER TROUGH OPENS UP AS A NORTHERN STREAM
SHORTWAVE TROUGH ALOFT MOVES EASTWARD INTO WESTERN NORTH
DAKOTA...THUS PRECIPITATION CHANCES DWINDLE AS THE NIGHT PROGRESSES.
SUNDAY...BREEZY TO WINDY...AND COOL WITH BRISK NORTHWEST FLOW ALOFT
AND DEEP UNIDIRECTIONAL WINDS. LOOKS LIKE ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS OVER AND NEAR OUR
NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES...WITH MOSTLY DRY
CONDITIONS ELSEWHERE.
SUNDAY NIGHT...MOIST OROGRAPHIC NORTHWEST FLOW ALOFT CONTINUES
PRODUCING SCATTERED TO NUMEROUS SNOW SHOWERS OVER AND NEAR OUR
SNOWY...SIERRA MADRE AND LARAMIE RANGES...DRY ELSEWHERE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 415 AM MDT SAT APR 18 2015
THE EXTENDED PERIOD WILL START OUT TRANQUIL AND THEN END
POTENTIALLY UNSETTLED. NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE
ON MON WITH A WEAK SHORTWAVE MOVING OVERHEAD DURING THE DAY. COULD
BE SOME LIGHT SNOW SHOWERS OVER THE SIERRA MADRE AND SNOWY
RANGES...BUT MUCH OF THE ACTIVITY WILL BE CONFINED TO NORTHERN
COLORADO. WITH 700MB TEMPS AROUND -6C...IT WILL BE ANOTHER DAY OF
BELOW NORMAL TEMPS. WE FINALLY GET TEMPS TO MODERATE SOME BY TUES
AND ESPECIALLY INTO WED...BACK INTO THE 50S AND 60S TO THE EAST OF
THE LARAMIE RANGE. A BUILDING SFC HIGH OVER THE NORTHERN PLAINS ON
THURS WILL CAUSE SOUTHEAST WINDS TO DEVELOP ACROSS THE PLAINS.
WEAK INSTABILITY WILL BE PRESENT ON THURS AFTN...SO INCLUDED A
SLIGHT OF TSTMS. A SHORTWAVE WILL THEN LIFT NORTHEASTWARD FROM
ARIZONA INTO COLORADO ON FRI. BOTH THE GFS AND ECMWF INDICATE THE
BEST CHANCE OF WIDESPREAD PRECIP COULD BE FRI AFTN INTO FRI NIGHT
WITH GOOD EASTERLY UPSLOPE FLOW OVER THE PLAINS. 700MB TEMPS ARE
AROUND -2C...SO COULD BE DEALING WITH ANOTHER CASE WHERE SNOW IS
LARGELY CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 545 AM MDT SAT APR 18 2015
THE LARGE AREA OF LIGHT SNOW IS CURRENTLY ALONG AND JUST WEST OF
THE LARAMIE RANGE AND MOVING WESTWARD. EXPECT IFR CONDITIONS AND LIGHT
SNOW THROUGH MUCH OF THE MORNING TO THE WEST OF THE LARAMIE RANGE.
IFR CIGS ARE EXPECTED THROUGH MID MORNING AT CYS BUT PRECIPITATION
HAS ENDED. MVFR CONDITIONS WILL GENERALLY PREVAIL THROUGH 18Z
OVER THE NEBRASKA PANHANDLE WITH PERIODS OF LIGHT
RAIN...ESPECIALLY OVER THE NORTHERN PANHANDLE. A COLD FRONT WILL
PUSH ACROSS THE PLAINS BY LATE THIS EVENING (AFTER 03Z) WITH
BREEZY NORTH WINDS.
&&
.FIRE WEATHER...
ISSUED AT 402 AM MDT SAT APR 18 2015
NO FIRE WEATHER ISSUES WITH RECENT WIDESPREAD
PRECIPITATION...AND PROJECTED HUMIDITIES AND WINDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL NOON MDT TODAY FOR WYZ114>117.
WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ103-105-106-
110-112.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...RUBIN
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...RUBIN