Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/21/12
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
930 AM PDT THU APR 19 2012
.SHORT TERM DISCUSSION...
MAIN SHORT TERM WEATHER FEATURE IS A RELATIVELY FLAT HIGH PRESSURE
RIDGE THAT WILL BE CENTERING ALONG THE WEST COAT BY THIS AFTERNOON.
MOST OF THE FORECAST AREA IS UNDER FAIR SKIES THIS MORNING WITH THE
EXCEPTION OF THE NORTHERN COUNTIES WHICH ARE SEEING SOME HEAVIER
CLOUDINESS. MODEL DATA INDICATES WEST COAST RIDGE WILL BEGIN TO
AMPLIFY TODAY. MAIN PRECIP FORECAST QUESTION WILL BE WHETHER
SHORTWAVE DISTURBANCES RIDING OVER TOP OF RIDGE WILL BRING PRECIP TO
THE NORTHERN MOUNTAINS. CURRENT RADAR IMAGERY SHOWS LIGHT PRECIP
JUST SKIRTING TO THE NORTH OF SHASTA COUNTY. NAM...GFS...GEM AND
ECMWF ALL PASTE LIGHT PRECIP OVER THE NORTHERN ZONES TODAY. JUDGING
BY CURRENT SATELLITE AND RADAR IMAGERY...BELIEVE MORNING RUC HAS
BEST HANDLE ON TODAYS SITUATION WHICH KEEPS PRECIP JUST NORTH OF THE
CWA MOST OF THE DAY BUT PUTS SLIGHT PRECIP THREAT OF LIGHT SHOWERS
OVER THE SOUTHERN CASCADES THIS AFTERNOON AS ONE LAST SHORTWAVE
DROPS DOWN BACK SIDE OF BUILDING RIDGE. BLENDED TPW IMAGE DOES SHOW
A LARGE 1.5 INCH PRECIPITABLE WATER BLOB OFF THE NORCAL COAST THIS
MORNING BUT GFS PROGS SHOW THIS AREA SHIFTING SOUTH AND NOT PLAYING
A SIGNIFICANT FACTOR. FOR THE REMAINDER OF THE CWA...LOOKS
LIKE A FAIRLY NICE DAY WITH JUST A FEW HIGH CLOUDS. AIRMASS WARMS
UNDER THE RIDGE TODAY. DAYTIME HIGHS EVEN UNDER CLOUDY AREAS SHOULD
COME IN A FEW DEGREES ABOVE NORMAL TODAY.
UPPER RIDGE BECOMES DOMINANT FEATURE INTO THE WEEKEND AS IT
AMPLIFIES AND SLIDES EASTWARD ACROSS THE REGION. TEMPERATURES WARM
ON FRIDAY THEN MORE ON SATURDAY WITH 1000-500 MB THICKNESS AND 850
MB TEMPS MAXING OUT ON SATURDAY. THEREFORE...SATURDAY SHOULD BE THE
WARMEST DAY OF THE FORECAST PERIOD WITH DAYTIME HIGHS AROUND 15
DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR. ALTHOUGH QUITE
WARM...QUICK LOOK AT TEMP RECORDS SHOW WE SHOULD REMAIN BELOW THEM
FOR THE MOST PART. OTHER THAN WELL ABOVE NORMAL TEMPS...FRIDAY AND
SATURDAY LOOK QUIET UNDER THE RIDGE EXCEPT FOR THE NORTHERN SIERRA
REGION WHERE VARIOUS MODELS HAVE PAINTED IN AN AFTERNOON PERIOD OF
INSTABILITY AND LIGHT PRECIP. CAPE AND LI VALUES CONSISTENT WITH A
SLIGHT THREAT OF AFTERNOON SIERRA THUNDERSTORMS. MOISTURE AND LIFT
ARE DEFINITELY VERY LIMITED BUT CONSIDERING HIGH CAPE VALUES
PREDICTED IN THIS REGION...CAN NOT RULE OUT ISOLATED THUNDERSTORM
THREAT ALL TOGETHER.
UPPER RIDGE BEGINS TO BREAK DOWN AND SHIFT EASTWARD SUNDAY. THIS
SHOULD BRING AT LEAST A LITTLE COOLING. MOST MODELS INDICATING A
MINOR SHORTWAVE RIDING UP WESTERN EDGE OF RIDGE WHICH COULD BRING A
SLIGHT THREAT OF PRECIP SUNDAY AFTERNOON TO THE NORTHERN COASTAL
RANGE. ELSEWHERE...CONDITIONS SHOULD REMAIN SPRINGLIKE FOR THE
REMAINDER OF THE WEEKEND.
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
UPPER LEVEL RIDGE AXIS SHIFTS EASTWARD EARLY NEXT WEEK AS A
POSITIVELY TILTED TROUGH APPROACHES. THIS WILL GRADUALLY COOL
TEMPERATURES TO NEAR NORMAL LEVELS BY MID TO THE LATTER HALF OF
THE WORK WEEK AS A COLD UPPER LEVEL LOW FROM THE GULF OF ALASKA
DROPS DOWN INTO THE REGION.
WEAK SHORTWAVE ENERGY MAY BRING SOME LIGHT SHOWERS TO THE NORTHERN
MOUNTAINS ON MONDAY AND TUESDAY. MORE SIGNIFICANT PRECIPITATION
IS POSSIBLE WEDNESDAY AND THURSDAY AS THE UPPER LOW PASS THROUGH.
THE LATEST GFS IS SHOWING A CONSIDERABLE MOISTURE PLUME LATE
WEDNESDAY WITH PW LEVELS AROUND AN INCH EXTENDED INLAND. IF MODEL
TRENDS CONTINUE THERE COULD BE SOME ACCUMULATING SNOW IN THE HIGHER
MOUNTAINS...ESPECIALLY THE NORTHERN SIERRA.
PACIFIC RIDGING AND DRIER WEATHER MAY RETURN AFTER FRIDAY WITH
THE TROUGH DEPARTING TO THE EAST. EK
&&
.AVIATION...
L MVFR POSS OVR SHASTA MTNS TDA WITH WKNG WRMFNT...OTRW UPR RDG BLDS
OVR INTR NORCAL NXT 24 HRS WITH VFR CONDS.
&&
.STO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
1030 PM EDT FRI APR 20 2012
.SYNOPSIS...
A MUCH NEEDED RAINFALL IS EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONT WILL GRADUALLY MOVE EASTWARD ACROSS THE AREA
SATURDAY...ACCOMPANIED BY SHOWERS OR A PERIOD OF RAIN. AN AREA OF
LOW PRESSURE WILL THEN APPROACH FROM THE SOUTH LATE SUNDAY INTO
MONDAY...BRINGING A WIDESPREAD...SOAKING RAIN TO THE REGION.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1030 PM EDT...SKIES REMAIN GENERALLY CLEAR TO PARTLY CLOUDY FROM
ALBANY N AND W...WITH MORE LOW CLOUDS DEVELOPING TO THE S/E. THE
CLOUDS TO THE S/E ARE IN RESPONSE TO INCREASING LOW LEVEL
MOISTURE...BEING TRANSPORTED NNW FROM SOUTH OF LONG ISLAND. A WEAK
SFC TROUGH IN THAT REGION HAS EVEN ALLOWED SOME ISOLATED SHOWERS
TO OCCUR...SOME OF WHICH MAY EVENTUALLY REACH PORTIONS OF THE MID
HUDSON VALLEY REGION AND NW CT AFTER MIDNIGHT.
FURTHER N AND W...THE LATEST RUC13 AND HRRR INDICATE A SLOWER SE
PROGRESSION OF SHOWERS ASSOCIATED WITH THE APPROACHING FRONT. AS
SUCH...WILL DECREASE POPS ACROSS FAR NW AREAS UNTIL CLOSER TO
SUNRISE...WHERE CHC POPS ARE INDICATED.
SOUTH WINDS WILL REMAIN RATHER GUSTY OVER THE NEXT 1-3 HOURS
WITHIN THE IMMEDIATE HUDSON RIVER VALLEY...ESP CLOSE TO AND WITHIN
THE CAPITAL REGION...WHERE SOME GUSTS OF 25-30 MPH WILL REMAIN
POSSIBLE. THE WINDS SHOULD DECREASE SLIGHTLY AFTER MIDNIGHT.
HOWEVER...THESE WINDS...ALONG WITH INCREASING CLOUDS...SHOULD KEEP
TEMPS FROM FALLING MUCH BELOW THE LOWER/MID 50S...WITH SOME 40S
POSSIBLE ACROSS PORTIONS OF THE NORTH COUNTRY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
MODELS GENERALLY IN GOOD AGREEMENT THAT WIDESPREAD RAINFALL WILL
OCCUR DURING THIS PERIOD AS THE FRONT MOVES THROUGH SATURDAY AND
SATURDAY NIGHT. THEN...AS THE UPPER LEVEL TROF DEEPENS AND CUTSOFF
TO OUR SOUTHWEST...STRONG LOW PRESSURE WILL FORM ALONG THE FRONTAL
BOUNDARY AND MOVE NORTH AND THEN NORTHWEST THROUGH THE REGION.
DETAILS IN TERMS OF TRACK AND EXACT PLACEMENT OF THE HEAVIEST PCPN
VARY SOMEWHAT FROM MODEL TO MODEL...BUT THEY ALL INDICATE NO LESS
THAN AN INCH OF RAIN WILL FALL...WITH MAXIMUM AMOUNTS OF 4 TO 5
INCHES POSSIBLE. AS THE LOW DEVELOPS AND MOVES NORTH...IT WILL
LIKELY ALSO GET COLD ENOUGH FOR SOME SNOW ACROSS THE HIGHER TERRAIN
SUNDAY NIGHT...ESPECIALLY IN THE ADIRONDACKS. ABOUT 1 TO 4 INCHES OF
SNOW IS FORECAST FOR THERE.
WITH THE EXCEPTION OF EXTREME SOUTHEAST AREAS...POPS ARE FORECAST
TO RISE TO LIKELY AND CATEGORICAL IN ALL AREAS BY LATE IN THE DAY ON
SATURDAY...THEN LIKELY/CATEGORICAL POPS FOR ALL AREAS THROUGH AT
LEAST MIDNIGHT SATURDAY NIGHT. AT THIS POINT THERE IS SOME MODEL
DISAGREEMENT WITH THE CANADIAN/NAM MODELS INDICATING THAT PCPN MAY
BRIEFLY COME TO AN END LATE SATURDAY NIGHT AND PART OF SUNDAY AS THE
FRONT MOVES FAR ENOUGH EAST TO BRING THE PCPN TO AN END AND BEFORE
THE AREA OF PCPN ASSOCIATED WITH THE SURFACE LOW MOVES IN. THE
GFS/ECMWF MODELS SHOW LITTLE IF ANY INTERRUPTION IN THE PCPN. FOR
NOW HAVE FORECAST POPS TO DECREASE TO CHANCE OR LESS OVER THE
NORTHWEST TWO THIRDS OF THE FORECAST AREA BY 12Z SUNDAY...THEN
INCREASE AGAIN TO LIKELY/CATEGORICAL BY LATE IN THE DAY ON SUNDAY.
CATEGORICAL POPS ALL AREAS SUNDAY NIGHT INTO EARLY MONDAY MORNING...
THEN DECREASING TO LIKELY LATER ON MONDAY.
HIGHS SATURDAY WILL BE IN THE MID 50S TO THE 60S NORTH...AND MID 60S
TO MID 70S SOUTH. WITH THE ENTIRE AREA IN THE COOLER AIR BY SUNDAY
MORNING...TEMPS WILL BE MORE UNIFORM WITH LOWS IN THE MID 30S AND
40S SATURDAY NIGHT. ON SUNDAY HIGHS WILL BE IN THE MID 40S TO MID
50S...LOWS SUNDAY NIGHT WILL BE IN THE 30S AND LOWER 40S. HIGHS
MONDAY IN THE MID 40S TO MID 50S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ON MONDAY NIGHT...THE LARGE CLOSED OFF 500 HPA LOW RESPONSIBLE FOR
THE RECENT RAINSTORM WILL BE MOVING UP ACROSS ACROSS WESTERN PA AND
WESTERN NY AND INTO SOUTHERN CANADA FOR TUESDAY MORNING.
MEANWHILE...THE MODELS STILL DON/T AGREE ON THE EXACT PLACEMENT OF
THE SFC LOW DURING THIS PERIOD...BUT IT SHOULD BE SOMEWHERE ACROSS
THE NORTH COUNTRY OF NORTHERN NY ON MON NIGHT AND INTO OTTAWA VALLEY
OF CANADA ON TUESDAY. WHILE THE STEADY RAINFALL WILL TAPER
OFF...THERE STILL WILL BE A CHANCE FOR WRAP AROUND RAIN SHOWERS FOR
MONDAY NIGHT AND INTO TUESDAY...WITH PLENTY OF CLOUDINESS. THE BEST
DEFORMATION PRECIP LOOKS TO REMAIN WELL WEST OF OUR AREA ACROSS
WESTERN NY. DUE TO LARGE CIRCULATION OF THE STORM...COLD AIR
ADVECTION WILL ACTUALLY BE OCCURRING ON W-SW WINDS ACROSS OUR
AREA...WITH 850 HPA TEMPS FALLING TO ABOUT -5 DEGREES C /ACCORDING
TO THE LATEST 12 UTC GFS AND ECMWF/. SFC TEMPS SHOULD REMAIN ABOVE
FREEZING FOR MOST VALLEY AREAS...BUT IT/S POSSIBLE FOR SOME WET SNOW
TO OCCUR ACROSS THE HIGH TERRAIN OF THE CATSKILLS/BERKSHIRES/GREENS
AND ADIRONDACKS DURING THE LATE NIGHT/EARLY MORNING HOURS. AT THIS
POINT...QPF LOOKS MINOR AT THIS POINT...WITH THE BULK OF THE PRECIP
WITH THIS STORM ALREADY HAVING OCCURRED IN THE FORM OF RAINFALL.
TEMPS MON NIGHT WILL FALL TO THE 30S IN MOST AREAS...AND MAX TEMPS
ON TUESDAY WILL RANGE ONLY FROM THE UPPER 30S ACROSS THE SRN
DACKS/GREENS TO THE MID 50S FOR THE HUDSON VALLEY.
THE LARGE STACKED SYSTEM WILL CONTINUE TO DRIFT NORTHWEST TOWARDS
JAMES BAY FOR TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...A LARGE SCALE
NEGATIVELY TITLED TROUGH WILL STILL REMAIN OVER THE AREA. BECAUSE OF
THIS...WILL STILL KEEP IN SOME CHC POPS FOR SHOWERS FOR TUESDAY
NIGHT INTO WEDNESDAY...WITH WET SNOW STILL POSSIBLE ACROSS THE HIGH
TERRAIN FOR THE LATE NIGHT HOURS. AS THE UPPER LOW DRIFTS AWAY...SO
DOES THE CHILLIEST AIR ALOFT...SO 850 HPA TEMPS SHOULD WARM TO
AROUND 0 C BY WED AFTN. THIS SHOULD HELP ALLOW TEMPS ON WEDNESDAY TO
BE A LITTLE WARMER THAN TUESDAY...WITH MAINLY MID TO UPPER 50S FOR
THE HUDSON VALLEY...AND MID TO UPPER 40S ACROSS THE HIGHER
ELEVATIONS. SOME PARTS OF THE MID HUDSON VALLEY COULD HIT AROUND 60
IF WINDS DOWNSLOPE OFF THE CATSKILLS JUST RIGHT.
A TROUGH LOOKS TO REMAIN OVER THE NORTHEAST FOR WED NIGHT INTO THE
REMAINDER OF THE WEEK. A FAST MOVING SHORTWAVE SWINGING AROUND THE
TROUGH MAY ALLOW FOR SOME ADDITIONAL PRECIP ON WED NIGHT INTO
THURSDAY...ALTHOUGH THE LATEST MODELS SEEM TO SHOW THIS SYSTEM
GENERALLY REMAINING SOUTH OF THE AREA. WILL CONTINUE THE CHC POPS
FOR WED NIGHT INTO THURSDAY...BUT START TO DRY THINGS OUT FOR
FRIDAY. TEMPS LOOK TO CONTINUE BELOW NORMAL FOR THE REMAINDER OF THE
WEEK...WITH 30S FOR WED AND THURSDAY NIGHTS...AND MAINLY 50S FOR
THURSDAY INTO FRIDAY.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST 03Z AT ALL TAF SITES.
THEREAFTER...SOME STRATUS WILL BEGIN EXPANDING NORTHWARD. IT
APPEARS THAT GENERALLY MVFR CIGS SHOULD OCCUR...FIRST AT
KPOU...THEN REACHING KALB AND KGFL AFTER MIDNIGHT. THERE IS SOME
POSSIBILITY OF IFR CIGS DEVELOPING AFTER 08Z...BUT DUE TO LOW
CONFIDENCE...HAVE NOT INCLUDED IN CURRENT SUITE OF TAFS.
ON SAT...MVFR AND ANY EMBEDDED IFR CIGS SHOULD BECOME VFR BY MID
TO LATE MORNING. HOWEVER...THE COLD FRONT WILL APPROACH FROM THE
NW DURING THE MIDDAY THROUGH MID AFTERNOON HOURS...AFFECTING KGFL
AND KALB FIRST...THEN KPOU LAST. ISOLATED SHOWERS MAY DEVELOP WITH
OR AHEAD OF THIS FRONTAL BOUNDARY...ALONG WITH A WIND SHIFT INTO
THE W TO NW. THEN...A PERIOD OF STEADIER LIGHT RAIN IS EXPECTED
BEHIND THE FRONTAL BOUNDARY...MAINLY FOR THE LATE AFTERNOON AND
EVENING HOURS. SOME MVFR CIGS WILL BE POSSIBLE BEHIND THE FRONT.
WINDS WILL REMAIN GUSTY FROM THE SOUTH AT KALB THROUGH 03Z AT
10-20 KT...WITH SOME GUSTS OF 25-30 KT POSSIBLE...BEFORE
DECREASING TO 8-12 KT AFTER MIDNIGHT. ELSEWHERE...EXPECT MAINLY
SOUTH WINDS AT 5-10 KT OVERNIGHT. ON SATURDAY...S TO SW WINDS WILL
INCREASE TO 8-12 KT...THEN SHIFT INTO THE W/NW BY AFTERNOON AT
SIMILAR SPEEDS.
.OUTLOOK...
SAT NT...MVFR/IFR. SHRAS LIKELY.
SUN-MON...VFR/MVFR...CHC IFR IN RAIN/HVY RAIN.
MON NT-TUE...VFR/MVFR...SLIGHT CHC/CHC -SHRAS.
&&
.FIRE WEATHER...
MUCH NEEDED RAINFALL EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK...BUT UNTIL THEN...ANOTHER WARM AND DRY DAY TODAY. A COLD
FRONTAL BOUNDARY WILL MOVE GRADUALLY EASTWARD ACROSS THE AREA
SATURDAY. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE SOUTH ON
SUNDAY AND IS EXPECTED TO MOVE INTO THE REGION ON MONDAY.
NEAR RED FLAG CONDITIONS THIS AFTERNOON WILL PROBABLY BE THE LAST
TIME IT IS THIS DRY FOR SOME TIME. ONE TO FOUR INCHES OF RAIN
POSSIBLE SATURDAY THROUGH MONDAY WHICH WILL MOISTEN ALL THE FUELS
THEN COOLER AND MORE MOIST CONDITIONS WILL CONTINUE THROUGH ALL
OF NEXT WEEK.
RELATIVE HUMIDITY SHOULD RECOVER TO BETWEEN 80 AND 100 PERCENT
TONIGHT...WITH MINIMUM RH VALUES IN THE 40 TO 60 PERCENT RANGE ON
SATURDAY WITH SHOWERS BECOMING LIKELY ACROSS THE AREA AS THE DAY
PROGRESSES.
&&
.HYDROLOGY...
A MUCH NEEDED RAINFALL EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONTAL BOUNDARY WILL MOVE GRADUALLY EASTWARD ACROSS
THE AREA SATURDAY. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE
SOUTH ON SUNDAY AND IS EXPECTED TO MOVE INTO THE REGION ON MONDAY.
HAVE GENERALLY MODIIED PREVIOUS QPF GRIDS BASED ON LATEST MODEL RUNS
AND HAVE COME UP WITH A TOTAL OF ABOUT 1.5 TO A LITTLE OVER 4 INCHES
ACROSS THE FORECAST AREA FROM SATURDAY THROUGH MIDDAY MONDAY.
HIGHEST RAINFALL AMOUNTS EXPECTED OVER THE SOUTHERN NEW YORK AND ALL
OF THE NEW ENGLAND ZONES...ESPECIALLY LITCHFIELD COUNTY. IN GENERAL
PRECIPITATION DEFICITS ACROSS THE FORECAST AREA FOR THE YEAR ARE
RUNNING 5 TO 10 INCHES. EXPECTED RAINFALL AMOUNTS GENERALLY PRODUCE
SIGNIFICANT WITHIN BANK RISES OR POSSIBLY SOME MINOR FLOODING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/GJM
NEAR TERM...KL/GJM
SHORT TERM...KL/GJM
LONG TERM...FRUGIS
AVIATION...KL
FIRE WEATHER...GJM
HYDROLOGY...IAA/KL/GJM
AREA FORECAST DISCUSSION
NWS ALBANY NY
810 PM EDT FRI APR 20 2012
.SYNOPSIS...
A MUCH NEEDED RAINFALL IS EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONT WILL GRADUALLY MOVE EASTWARD ACROSS THE AREA
SATURDAY...ACCOMPANIED BY SHOWERS OR A PERIOD OF RAIN. AN AREA OF
LOW PRESSURE WILL THEN APPROACH FROM THE SOUTH LATE SUNDAY INTO
MONDAY...BRINGING A WIDESPREAD...SOAKING RAIN TO THE REGION.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 745 PM EDT...SKIES REMAIN GENERALLY CLEAR FROM ALBANY N AND
W...WITH SOME CLOUDS DEVELOPING TO THE S/E. THE CLOUDS TO THE S/E
ARE IN RESPONSE TO INCREASING LOW LEVEL MOISTURE...BEING
TRANSPORTED NNW FROM SOUTH OF LONG ISLAND. A WEAK SFC TROUGH IN
THAT REGION HAS EVEN ALLOWED SOME ISOLATED SHOWERS TO OCCUR...SOME
OF WHICH MAY EVENTUALLY REACH PORTIONS OF THE MID HUDSON VALLEY
REGION AND NW CT AFTER MIDNIGHT.
FURTHER N AND W...THE LATEST RUC13 AND HRRR INDICATE A SLOWER SE
PROGRESSION OF SHOWERS ASSOCIATED WITH THE APPROACHING FRONT. AS
SUCH...WILL DECREASE POPS ACROSS FAR NW AREAS UNTIL CLOSER TO
SUNRISE...WHERE CHC POPS ARE INDICATED.
SOUTH WINDS WILL REMAIN RATHER GUSTY OVER THE NEXT 1-3 HOURS
WITHIN THE IMMEDIATE HUDSON RIVER VALLEY...ESP CLOSE TO AND WITHIN
THE CAPITAL REGION...WHERE SOME GUSTS OF 25-30 MPH WILL REMAIN
POSSIBLE. THE WINDS SHOULD DECREASE SLIGHTLY TOWARD AND AFTER
MIDNIGHT. HOWEVER...THESE WINDS...ALONG WITH INCREASING
CLOUDS...SHOULD KEEP TEMPS FROM FALLING MUCH BELOW THE LOWER/MID
50S...WITH SOME 40S POSSIBLE ACROSS PORTIONS OF THE NORTH COUNTRY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
MODELS GENERALLY IN GOOD AGREEMENT THAT WIDESPREAD RAINFALL WILL
OCCUR DURING THIS PERIOD AS THE FRONT MOVES THROUGH SATURDAY AND
SATURDAY NIGHT. THEN...AS THE UPPER LEVEL TROF DEEPENS AND CUTSOFF
TO OUR SOUTHWEST...STRONG LOW PRESSURE WILL FORM ALONG THE FRONTAL
BOUNDARY AND MOVE NORTH AND THEN NORTHWEST THROUGH THE REGION.
DETAILS IN TERMS OF TRACK AND EXACT PLACEMENT OF THE HEAVIEST PCPN
VARY SOMEWHAT FROM MODEL TO MODEL...BUT THEY ALL INDICATE NO LESS
THAN AN INCH OF RAIN WILL FALL...WITH MAXIMUM AMOUNTS OF 4 TO 5
INCHES POSSIBLE. AS THE LOW DEVELOPS AND MOVES NORTH...IT WILL
LIKELY ALSO GET COLD ENOUGH FOR SOME SNOW ACROSS THE HIGHER TERRAIN
SUNDAY NIGHT...ESPECIALLY IN THE ADIRONDACKS. ABOUT 1 TO 4 INCHES OF
SNOW IS FORECAST FOR THERE.
WITH THE EXCEPTION OF EXTREME SOUTHEAST AREAS...POPS ARE FORECAST
TO RISE TO LIKELY AND CATEGORICAL IN ALL AREAS BY LATE IN THE DAY ON
SATURDAY...THEN LIKELY/CATEGORICAL POPS FOR ALL AREAS THROUGH AT
LEAST MIDNIGHT SATURDAY NIGHT. AT THIS POINT THERE IS SOME MODEL
DISAGREEMENT WITH THE CANADIAN/NAM MODELS INDICATING THAT PCPN MAY
BRIEFLY COME TO AN END LATE SATURDAY NIGHT AND PART OF SUNDAY AS THE
FRONT MOVES FAR ENOUGH EAST TO BRING THE PCPN TO AN END AND BEFORE
THE AREA OF PCPN ASSOCIATED WITH THE SURFACE LOW MOVES IN. THE
GFS/ECMWF MODELS SHOW LITTLE IF ANY INTERRUPTION IN THE PCPN. FOR
NOW HAVE FORECAST POPS TO DECREASE TO CHANCE OR LESS OVER THE
NORTHWEST TWO THIRDS OF THE FORECAST AREA BY 12Z SUNDAY...THEN
INCREASE AGAIN TO LIKELY/CATEGORICAL BY LATE IN THE DAY ON SUNDAY.
CATEGORICAL POPS ALL AREAS SUNDAY NIGHT INTO EARLY MONDAY MORNING...
THEN DECREASING TO LIKELY LATER ON MONDAY.
HIGHS SATURDAY WILL BE IN THE MID 50S TO THE 60S NORTH...AND MID 60S
TO MID 70S SOUTH. WITH THE ENTIRE AREA IN THE COOLER AIR BY SUNDAY
MORNING...TEMPS WILL BE MORE UNIFORM WITH LOWS IN THE MID 30S AND
40S SATURDAY NIGHT. ON SUNDAY HIGHS WILL BE IN THE MID 40S TO MID
50S...LOWS SUNDAY NIGHT WILL BE IN THE 30S AND LOWER 40S. HIGHS
MONDAY IN THE MID 40S TO MID 50S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ON MONDAY NIGHT...THE LARGE CLOSED OFF 500 HPA LOW RESPONSIBLE FOR
THE RECENT RAINSTORM WILL BE MOVING UP ACROSS ACROSS WESTERN PA AND
WESTERN NY AND INTO SOUTHERN CANADA FOR TUESDAY MORNING.
MEANWHILE...THE MODELS STILL DON/T AGREE ON THE EXACT PLACEMENT OF
THE SFC LOW DURING THIS PERIOD...BUT IT SHOULD BE SOMEWHERE ACROSS
THE NORTH COUNTRY OF NORTHERN NY ON MON NIGHT AND INTO OTTAWA VALLEY
OF CANADA ON TUESDAY. WHILE THE STEADY RAINFALL WILL TAPER
OFF...THERE STILL WILL BE A CHANCE FOR WRAP AROUND RAIN SHOWERS FOR
MONDAY NIGHT AND INTO TUESDAY...WITH PLENTY OF CLOUDINESS. THE BEST
DEFORMATION PRECIP LOOKS TO REMAIN WELL WEST OF OUR AREA ACROSS
WESTERN NY. DUE TO LARGE CIRCULATION OF THE STORM...COLD AIR
ADVECTION WILL ACTUALLY BE OCCURRING ON W-SW WINDS ACROSS OUR
AREA...WITH 850 HPA TEMPS FALLING TO ABOUT -5 DEGREES C /ACCORDING
TO THE LATEST 12 UTC GFS AND ECMWF/. SFC TEMPS SHOULD REMAIN ABOVE
FREEZING FOR MOST VALLEY AREAS...BUT IT/S POSSIBLE FOR SOME WET SNOW
TO OCCUR ACROSS THE HIGH TERRAIN OF THE CATSKILLS/BERKSHIRES/GREENS
AND ADIRONDACKS DURING THE LATE NIGHT/EARLY MORNING HOURS. AT THIS
POINT...QPF LOOKS MINOR AT THIS POINT...WITH THE BULK OF THE PRECIP
WITH THIS STORM ALREADY HAVING OCCURRED IN THE FORM OF RAINFALL.
TEMPS MON NIGHT WILL FALL TO THE 30S IN MOST AREAS...AND MAX TEMPS
ON TUESDAY WILL RANGE ONLY FROM THE UPPER 30S ACROSS THE SRN
DACKS/GREENS TO THE MID 50S FOR THE HUDSON VALLEY.
THE LARGE STACKED SYSTEM WILL CONTINUE TO DRIFT NORTHWEST TOWARDS
JAMES BAY FOR TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...A LARGE SCALE
NEGATIVELY TITLED TROUGH WILL STILL REMAIN OVER THE AREA. BECAUSE OF
THIS...WILL STILL KEEP IN SOME CHC POPS FOR SHOWERS FOR TUESDAY
NIGHT INTO WEDNESDAY...WITH WET SNOW STILL POSSIBLE ACROSS THE HIGH
TERRAIN FOR THE LATE NIGHT HOURS. AS THE UPPER LOW DRIFTS AWAY...SO
DOES THE CHILLIEST AIR ALOFT...SO 850 HPA TEMPS SHOULD WARM TO
AROUND 0 C BY WED AFTN. THIS SHOULD HELP ALLOW TEMPS ON WEDNESDAY TO
BE A LITTLE WARMER THAN TUESDAY...WITH MAINLY MID TO UPPER 50S FOR
THE HUDSON VALLEY...AND MID TO UPPER 40S ACROSS THE HIGHER
ELEVATIONS. SOME PARTS OF THE MID HUDSON VALLEY COULD HIT AROUND 60
IF WINDS DOWNSLOPE OFF THE CATSKILLS JUST RIGHT.
A TROUGH LOOKS TO REMAIN OVER THE NORTHEAST FOR WED NIGHT INTO THE
REMAINDER OF THE WEEK. A FAST MOVING SHORTWAVE SWINGING AROUND THE
TROUGH MAY ALLOW FOR SOME ADDITIONAL PRECIP ON WED NIGHT INTO
THURSDAY...ALTHOUGH THE LATEST MODELS SEEM TO SHOW THIS SYSTEM
GENERALLY REMAINING SOUTH OF THE AREA. WILL CONTINUE THE CHC POPS
FOR WED NIGHT INTO THURSDAY...BUT START TO DRY THINGS OUT FOR
FRIDAY. TEMPS LOOK TO CONTINUE BELOW NORMAL FOR THE REMAINDER OF THE
WEEK...WITH 30S FOR WED AND THURSDAY NIGHTS...AND MAINLY 50S FOR
THURSDAY INTO FRIDAY.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH AT LEAST 03Z AT ALL TAF SITES.
THEREAFTER...SOME STRATUS WILL BEGIN EXPANDING NORTHWARD. IT
APPEARS THAT GENERALLY MVFR CIGS SHOULD OCCUR...FIRST AT
KPOU...THEN REACHING KALB AND KGFL AFTER MIDNIGHT. THERE IS SOME
POSSIBILITY OF IFR CIGS DEVELOPING AFTER 08Z...BUT DUE TO LOW
CONFIDENCE...HAVE NOT INCLUDED IN CURRENT SUITE OF TAFS.
ON SAT...MVFR AND ANY EMBEDDED IFR CIGS SHOULD BECOME VFR BY MID
TO LATE MORNING. HOWEVER...THE COLD FRONT WILL APPROACH FROM THE
NW DURING THE MIDDAY THROUGH MID AFTERNOON HOURS...AFFECTING KGFL
AND KALB FIRST...THEN KPOU LAST. ISOLATED SHOWERS MAY DEVELOP WITH
OR AHEAD OF THIS FRONTAL BOUNDARY...ALONG WITH A WIND SHIFT INTO
THE W TO NW. THEN...A PERIOD OF STEADIER LIGHT RAIN IS EXPECTED
BEHIND THE FRONTAL BOUNDARY...MAINLY FOR THE LATE AFTERNOON AND
EVENING HOURS. SOME MVFR CIGS WILL BE POSSIBLE BEHIND THE FRONT.
WINDS WILL REMAIN GUSTY FROM THE SOUTH AT KALB THROUGH 03Z AT
10-20 KT...WITH SOME GUSTS OF 25-30 KT POSSIBLE...BEFORE
DECREASING TO 8-12 KT AFTER MIDNIGHT. ELSEWHERE...EXPECT MAINLY
SOUTH WINDS AT 5-10 KT OVERNIGHT. ON SATURDAY...S TO SW WINDS WILL
INCREASE TO 8-12 KT...THEN SHIFT INTO THE W/NW BY AFTERNOON AT
SIMILAR SPEEDS.
.OUTLOOK...
SAT NT...MVFR/IFR. SHRAS LIKELY.
SUN-MON...VFR/MVFR...CHC IFR IN RAIN/HVY RAIN.
MON NT-TUE...VFR/MVFR...SLIGHT CHC/CHC -SHRAS.
&&
.FIRE WEATHER...
MUCH NEEDED RAINFALL EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK...BUT UNTIL THEN...ANOTHER WARM AND DRY DAY TODAY. A COLD
FRONTAL BOUNDARY WILL MOVE GRADUALLY EASTWARD ACROSS THE AREA
SATURDAY. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE SOUTH ON
SUNDAY AND IS EXPECTED TO MOVE INTO THE REGION ON MONDAY.
NEAR RED FLAG CONDITIONS THIS AFTERNOON WILL PROBABLY BE THE LAST
TIME IT IS THIS DRY FOR SOME TIME. ONE TO FOUR INCHES OF RAIN
POSSIBLE SATURDAY THROUGH MONDAY WHICH WILL MOISTEN ALL THE FUELS
THEN COOLER AND MORE MOIST CONDITIONS WILL CONTINUE THROUGH ALL
OF NEXT WEEK.
RELATIVE HUMIDITY SHOULD RECOVER TO BETWEEN 80 AND 100 PERCENT
TONIGHT...WITH MINIMUM RH VALUES IN THE 40 TO 60 PERCENT RANGE ON
SATURDAY WITH SHOWERS BECOMING LIKELY ACROSS THE AREA AS THE DAY
PROGRESSES.
&&
.HYDROLOGY...
A MUCH NEEDED RAINFALL EXPECTED THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONTAL BOUNDARY WILL MOVE GRADUALLY EASTWARD ACROSS
THE AREA SATURDAY. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE
SOUTH ON SUNDAY AND IS EXPECTED TO MOVE INTO THE REGION ON MONDAY.
HAVE GENERALLY MODIIED PREVIOUS QPF GRIDS BASED ON LATEST MODEL RUNS
AND HAVE COME UP WITH A TOTAL OF ABOUT 1.5 TO A LITTLE OVER 4 INCHES
ACROSS THE FORECAST AREA FROM SATURDAY THROUGH MIDDAY MONDAY.
HIGHEST RAINFALL AMOUNTS EXPECTED OVER THE SOUTHERN NEW YORK AND ALL
OF THE NEW ENGLAND ZONES...ESPECIALLY LITCHFIELD COUNTY. IN GENERAL
PRECIPITATION DEFICITS ACROSS THE FORECAST AREA FOR THE YEAR ARE
RUNNING 5 TO 10 INCHES. EXPECTED RAINFALL AMOUNTS GENERALLY PRODUCE
SIGNIFICANT WITHIN BANK RISES OR POSSIBLY SOME MINOR FLOODING.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/GJM
NEAR TERM...KL/GJM
SHORT TERM...KL/GJM
LONG TERM...FRUGIS
AVIATION...KL
FIRE WEATHER...GJM
HYDROLOGY...KL/GJM/IAA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1008 PM EDT FRI APR 20 2012
.UPDATE...
SOUTHWEST PROPAGATING OUTFLOW BOUNDARIES FROM EARLIER CONVECTION
ARE SPARKING FURTHER SHOWERS AND THUNDERSTORMS BACK ACROSS
INTERIOR AREAS AND TO THE GULF COAST. LATEST HRRR ALSO DEPICTS
CONVECTION IN THE CENTRAL AND WESTERN GULF OF MEXICO OUT AHEAD OF
THE LARGER H5 LOW TO PUSH ASHORE AROUND 05Z. INCREASED POPS TO
ADJUST FOR CURRENT RADAR TRENDS.
&&
.PREV DISCUSSION... /ISSUED 803 PM EDT FRI APR 20 2012/
UPDATE...
SENT UPDATE TO INCREASE POPS ACROSS ALL OF SOUTH FLORIDA THIS
EVENING...ESPECIALLY ACROSS PALM BEACH AND BROWARD COUNTIES AND
ACROSS LAKE OKEECHOBEE. SHOWERS AND THUNDERSTORMS CONTINUE TO PUSH
TO THE EAST BUT ARE ALSO BACK BUILDING. STRONGEST STORMS ARE IN A
WEAKENING PHASE AND SHOULD CONTINUE TO WEAKEN THROUGH THE LATE
EVENING HOURS.
PREV DISCUSSION... /ISSUED 747 PM EDT FRI APR 20 2012/
AVIATION...
ONGOING CONVECTION CONTINUES TO AFFECT EAST COAST TERMINALS WITH
THE EXCEPTION OF KMIA AND KTMB ATTM. ACTIVITY IS SLOWLY PUSHING TO THE
EAST BUT LATEST TRENDS DEPICT CB TOWERS BUILDING BACK TO THE WEST.
CONVECTION SHOULD WEAKEN SOMEWHAT DURING THE OVERNIGHT HOURS
BEFORE ANOTHER WAVE OF SHRAS/TSRAS BEGIN TO PUSH INTO SOUTH
FLORIDA SATURDAY MORNING. ACTIVITY DURING THE DAY ON SATURDAY AND
ESPECIALLY SATURDAY EVENING IS EXPECTED TO BE STRONGER AND MORE
EXTENSIVE.
PREV DISCUSSION... /ISSUED 215 PM EDT FRI APR 20 2012/
STRONG TO SEVERE STORMS POSSIBLE OVER S FLA THIS WEEKEND...
TWO ROUNDS OF THUNDERSTORM ACTIVITY FOR SOUTH FLORIDA...
AMPLIFYING UPPER RIDGE OVER THE RKY MTN CHAIN INTO S CANADA ALLOWING
A DEEPENING TROUGH OVER THE CENTRAL GREAT PLAINS TO PLUNGE INTO THE
LOWER MS RIVER VALLEY WITH A CLOSED LOW DEVELOPING OFF OF THE GULF
COAST DURING THE DAY SATURDAY. THIS CLOSED LOW WILL CONTINUE TO DIVE
SE INTO THE CENTRAL GULF BEFORE LIFTING TO THE NE SATURDAY EVENING
AND CROSSING N FLA SUNDAY MORNING AND THEN NE ALONG THE SE U.S.
COAST SUNDAY AFTERNOON. ANOTHER SHORT WAVE DIVING SE ACROSS THE
GREAT LAKES REGION ABSORBS THE E COAST LOW INTO A CLOSED LOW OVER
THE E OHIO RIVER VALLEY THAT MOVES NORTHWARD INTO S CANADA.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...AS THE UPPER TROUGH
CONTINUES TO DEVELOP...THE S FLA AREA WILL BE UNDER AN INCREASING
AND BECOMING DIVERGENT SW WIND FLOW ALOFT WITH EMBEDDED IMPULSES
GENERATING CONVECTION. THE DIURNAL CONVECTION TODAY WILL LINGER INTO
THE EVENING HOURS MAINLY NE BUT DEVELOPING ACTIVITY OVER THE S
CENTRAL GULF WILL SPREAD NE AND ONTO THE W COAST LATE TONIGHT AND
SPREAD ACROSS S FLA TO THE E COAST BY SATURDAY MORNING. ACTIVITY
COULD GET ACTIVE ESPECIALLY ON THE W COAST BUT WEAKEN SOME UPON
REACHING THE E COAST. WITH CLOUD COVER AND A SLIGHTLY MORE STABLE
ATMOSPHERE EARLY SATURDAY...HEAVY CONVECTION MAY BE LIMITED DURING
THE DAY BUT A LITTLE HEATING IN THE MOIST ATMOSPHERE ( BECOMING 2
STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR ) WITH
POSSIBLE LAKE/SEA BREEZES...SHOWER/THUNDERSTORM ACTIVITY CAN AGAIN
BE EXPECTED. WITH THE INCREASED MOISTURE IN THE ATMOSPHERE
POSSIBLE TRAINING OF ECHOES...LOCALLY HEAVY RAINS...WILL NOT BE
OUT OF THE QUESTION ESPECIALLY W. LATE SATURDAY AFTERNOON AND INTO
SATURDAY NIGHT....IT APPEARS THAT THE STRONGEST IMPULSE WILL MOVE
OVER S FLA. STRONG STORMS CAN BE EXPECTED TO DEVELOP IN THE GULF AND
ACROSS S FLA WITH EVEN SEVERE STORMS POSSIBLE. THE MAIN THREAT IS
EXPECTED TO BE DAMAGING WINDS BUT ISOLATED TORNADOES AND LARGE HAIL
ARE ALSO POSSIBLE. DECREASING CONVECTION EXPECTED SUNDAY WITH ALL
ACTIVITY ENDING SUNDAY NIGHT. UNCERTAINTY STILL EXISTS AS THE MODELS
HAVE BEEN WAFFLING ON THE TIMING BUT THIS IS THE CURRENT THINKING.
RESIDENTS AND VISITORS IN SOUTH FLORIDA ARE URGED TO KEEP ABREAST OF
THE LOCAL FORECAST AS THIS WEATHER SITUATION CONTINUES TO UNFOLD.
EXTENDED PERIOD...MONDAY THROUGH FRIDAY...A DRY NW WIND FLOW WILL
BE OVER S FLA THROUGH THE PERIOD WITH NO PRECIPITATION EXPECTED.
MAX/MIN TEMPS A BIT BELOW NORMAL FOR A COUPLE OF DAYS THEN A SLOW
WARMING REND TOWARD THE END OF THE WEEK.
MARINE...MARINE CONDITIONS REALLY BEGIN TO DETERIORATE AHEAD OF THE
APPROACHING LOW/FRONT SATURDAY AFTERNOON WITH WINDS INCREASING ABOVE
ADVISORY CRITERIA POSSIBLY AS EARLY AS SATURDAY NIGHT. THE INCREAS
-ING SW WIND FLOW WILL LEAD TO AN INCREASE IN THE RISK OF RIP
CURRENTS AND ROUGH SURF ALONG THE WEST COAST OF S FLA BEGINNING AS
EARLY AS SATURDAY AFTERNOON. SOME COASTAL FLOODING ALONG THE W
COAST OF S FLA WILL ALSO BE POSSIBLE. WATER LEVELS MAY REACH 1 TO 2
FT ABOVE THE REGULAR HIGH TIDE FROM LATE SATURDAY AFTERNOON THROUGH
SUNDAY AFTERNOON ANYWHERE FROM MARCO ISLAND TO EVERGLADES CITY. ANY
AREAS TYPICALLY VULNERABLE TO MINOR COASTAL FLOODING SHOULD CONTINUE
TO MONITOR THE LATEST FORECASTS AS THIS GULF LOW PRESSURE SYSTEM
DEVELOPS AND TRACKS EAST OVER THE FL PENINSULA.
FIRE WEATHER...NO CONCERNS AT THIS TIME BUT MUCH DRIER CONDITIONS
ARE EXPECTED TO SPREAD ACROSS S FLA EARLY NEXT WEEK WITH RH FALLING
AT OR BELOW 35%.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 81 70 85 / 60 80 70 50
FORT LAUDERDALE 73 82 71 86 / 50 80 70 50
MIAMI 72 83 70 85 / 50 80 70 50
NAPLES 68 82 69 81 / 50 80 70 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
214 PM EDT THU APR 19 2012
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER NEAR THE AREA THROUGH FRIDAY.
A STRONG LOW PRESSURE SYSTEM WILL THEN AFFECT THE REGION THIS
WEEKEND FOLLOWED BY COOL AND DRY HIGH PRESSURE THROUGH THE MIDDLE
OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY THIS AFTERNOON...LOW OVERCAST CONTINUES ACROSS THE FORECAST
AREA HELPING TO KEEP TEMPERATURES DOWN IN THE MID TO UPPER 60S IN
MOST LOCATIONS. SHOWER ACTIVITY HAS DIMINISHED CONSIDERABLY WITH
JUST ISOLATED TO WIDELY SCATTERED SHOWERS ONGOING. BREAKS IN THE
OVERCAST ARE TRYING TO WORK THEIR WAY NORTHWARD TOWARD THE
ALTAMAHA AND MAY ALLOW AREAS ACROSS SE GA TO SCATTER OUT THIS
AFTERNOON. ADJUSTED HOURLY TEMPS A BIT BUT OTHERWISE NO
SIGNIFICANT CHANGES. PREVIOUS DISCUSSION FOLLOWS BELOW.
SURFACE ANALYSIS SHOWS THE FRONT LINGERING JUST OFF THE SC/GA
COAST WITH COOL NE FLOW IN PLACE ACROSS INLAND LOCATIONS.
ALOFT...A WEAK 500 MB PATTERN PERSISTS WITH A WEAK SHORTWAVE
APPROACHING FROM THE WEST NOTED IN WATER VAPOR IMAGERY. THERE IS
ALSO STILL QUITE A BIT OF DRY AIR IN THE UPPER LEVELS AS SEEN IN
THE 12Z SOUNDING. LOW OVERCAST STRATUS COVER THE FORECAST AREA
WITH MAINLY ISOLATED TO SCATTERED LIGHT RAIN SHOWERS. MOST OF THE
FORECAST CHALLENGES FOR TODAY HINGE GREATLY ON THE EVENTUAL
EVOLUTION OF THE LOW STRATUS AND THE IN-SITU WEDGE THAT IS IN
PLACE. AS IS USUALLY THE CASE...LARGER SCALE MODELS ARE SCOURING
OUT THE LOW CLOUDS AND THE WEDGE BY EARLY AFTERNOON AND ALLOWING
AT LEAST PARTIAL CLEARING TODAY. SHORTER RANGE MESOSCALE MODELS
SUCH AS THE LOCAL WRF AND HRRR AREN/T AS OPTIMISTIC...AND ALLOW
THE NE FLOW AND LOW CLOUDS TO HANG AROUND FOR JUST ABOUT THE
ENTIRE DAY. I HAVE FAVORED THE PESSIMISTIC SOLUTION WHICH HAS
RESULTED IN SOME ADJUSTMENTS TO THE GOING FORECAST. I HAVE COOLED
HIGHS TODAY BY SEVERAL DEGREES BASED ON BROKEN TO OVERCAST SKIES
STAYING IN PLACE THROUGH THE AFTERNOON. CURRENTLY TEMPS ARE RISING
VERY SLOWLY INTO THE LOW TO MID 60S...AND EVEN THOUGH LOW LEVEL
THICKNESS VALUES SUPPORT LOW 80S TODAY...I HAVE TAPERED TEMPS DOWN
INTO THE LOW TO MID 70S. AREAS ACROSS FAR SE GA STAND THE BEST
CHANCE OF SEEING SOME CLEARING...SO HIGHS IN THE UPPER 70S DOWN
AROUND DARIEN SEEM PLAUSIBLE. CONCERNING POPS...THE CURRENT SHOWER
COVERAGE IS DUE TO SOME ISENTROPIC LIFT AND WEAK UPPER ASCENT JUST
AHEAD OF THE APPROACHING SHORTWAVE. WITH MUCH COOLER SURFACE TEMPS
TODAY...COMBINED WITH MOIST PROFILES UP TO AROUND 600 MB AND WEAK
LAPSE RATES...ITS GOING TO BE DIFFICULT TO GET MUCH IF ANY
CONVECTION GOING THIS AFTERNOON. I HAVE MAINTAINED CHANCE POPS TO
ACCOUNT FOR SOME SHOWER ACTIVITY...BUT SHORT RANGE MODELS SUCH AS
THE HRRR SUPPORT VERY LITTLE IN THE WAY OF COVERAGE. WILL KEEP AN
EYE ON POP TRENDS FOR THE EARLY AFTERNOON UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...SCATTERED SHOWERS/TSTMS WILL QUICKLY WIND DOWN AFTER
SUNSET WITH THE LOSS OF INSOLATION AND WEAK NVA DEVELOPS IN THE
WAKE OF THE PASSING SHORTWAVE. ANY CLEARING THAT TOOK PLACE OVER
FAR SOUTHERN SOUTHEAST GEORGIA WILL QUICKLY GIVE WAY TO MOSTLY
CLOUDY SKIES AS LOW/MID-LEVEL CLOUDS FILL BACK IN. LOWS WILL RANGE
FROM THE UPPER 50S INLAND-LOWER 60S COAST.
FRIDAY...A WEAK SFC LOW/SURFACE TROUGH WILL LINGER OVER THE
FORECAST AREA EARLY BEFORE GRADUALLY LIFTING NORTH BY FRIDAY
AFTERNOON. ONSHORE FLOW WILL THEN DEVELOP AS WEAK HIGH PRESSURE
SLIDES OFF THE MID ATLANTIC COAST WHILE A LARGE AND DEEP LOW
DEVELOPS OVER THE NORTHERN GULF OF MEXICO. OVERALL HIGH TEMPS ARE
EXPECTED TO REACH THE LOW 80S WITH SOUTHERLY FLOW AND MODEST MID
LVL RIDGING AHEAD OF THE APPROACHING SYSTEM TO OUR WEST. DESPITE
RIDGING ALOFT...ENHANCED MOISTURE SHOULD PRODUCE A FEW SHOWERS AND
PERHAPS A FEW THUNDERSTORMS OVER THE AREA...ESPECIALLY ALONG AN
AFTERNOON SEABREEZE.
SATURDAY AND SUNDAY...A LARGE AND POTENTIALLY STRONG LOW PRESSURE
SYSTEM WILL AFFECT THE SOUTHEAST THIS WEEKEND. SEVERE WEATHER WILL
BE POSSIBLE WITH THIS SYSTEM BUT WILL BE HIGHLY DEPENDENT ON THE
TRACK AND TIMING OF A SFC LOW THAT DEVELOPS OVER THE NORTHERN GULF.
AT THIS TIME...A TROUGH OF LOW PRESSURE IS EXPECTED TO DIG OVER THE
CENTRAL UNITED STATES AND ENCOUNTER A STRONG SOUTHERN STREAM
JET...WHICH WILL AID IN THE DEVELOPMENT AND DEEPENING OF A SFC LOW
OVER THE NORTHERN GULF OF MEXICO. SEVERAL WEAK H5 SHORTWAVES WILL THEN
SHIFT AROUND AND AHEAD THE PERIPHERY OF THE DEEPENING LOW WHILE IT
SLOWLY PROGRESSES EAST. CHANCES OF SHOWERS/THUNDERSTORMS WILL
INCREASE TO LIKELY SATURDAY EVENING AS THESE H5 SHORTWAVES ENCOUNTER
AN INCREASINGLY MOIST BOUNDARY LAYER OVER THE SOUTHEASTERN UNITED
STATES. LATEST GUIDANCE SUGGESTS A MORE SOUTHERN TRACK OF THE SFC
LOW...WHICH WOULD SHIFT AN ENHANCED PERIOD OF SEVERE WEATHER SOUTH
OF THE FORECAST AREA. HOWEVER...SHOULD THE TRACK OF THE SFC LOW MAKE
A SLIGHT TREND NORTH...STRONG THUNDERSTORMS MAY BE POSSIBLE OVER
SOUTHEAST GEORGIA SOMETIME BETWEEN SATURDAY EVENING INTO SUNDAY
MORNING. PWATS BETWEEN 1.5 TO 2.0 INCHES ALSO SUGGEST THE POTENTIAL
FOR HEAVY RAINFALL...ESPECIALLY ALONG THE SOUTHEAST GEORGIA COAST.
DESPITE INCREASING CLOUD COVER...HIGH TEMPS WILL REACH THE LOW
80S...WITH WARMEST TEMPS OVER SOUTHEAST GEORGIA.
SHOWERS/THUNDERSTORMS WILL BE POSSIBLE THROUGH SUNDAY MORNING BEFORE
A COLD FRONT PASSES THROUGH THE FORECAST AREA. CONDITIONS SHOULD
THEN RAPIDLY IMPROVE SUNDAY AFTERNOON/EVENING AS HIGH PRESSURE
SETTLES OVER THE REGION BEHIND THE DEPARTING LOW. HAVE LOWERED POPS
TO LOW END CHANCE BY SUNDAY EVENING. OVERALL TEMPS WILL BE
COOLER...IN THE LOW/MID 70S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
COOL AND DRY CONDITIONS WILL BE IN PLACE THROUGH THE MIDDLE OF NEXT
WEEK AS SFC HIGH PRESSURE REMAINS OVER THE FORECAST AREA WHILE A
MID/UPPER LVL TROUGH SLOWLY DRIFTS OFF THE ATLANTIC SEABOARD.
OVERALL...HIGH TEMPS WILL BE IN THE MID 70S MONDAY/TUESDAY BEFORE
GRADUALLY WARMING INTO THE UPPER 70S/LOWER 80S BY LATE WEEK.
OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO MID 50S. DRY
CONDITIONS ARE EXPECTED TO PERSIST THROUGH LATE WEEK AS MID LVL
RIDGING EXPANDS OVER THE SOUTHEASTERN UNITED STATES.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
IT APPEARS THAT THE LOW CEILINGS ARE FINALLY STARTING TO LIFT EVER
SO SLOWLY ACROSS THE REGION. PREVAILING MVFR IS EXPECTED STILL FOR
MUCH OF THE AFTERNOON AS THE STATIONARY FRONT LINGERS JUST
OFFSHORE. VISIBLE SATELLITE IMAGERY SHOWS BREAKS IN THE OVERCAST
TRYING TO WORK NORTHWARD INTO THE ALTAMAHA WHICH SHOULD ALLOW KSAV
TO GO VFR IN THE NEXT COUPLE OF HOURS. KCHS MAY ALSO EXPERIENCE A
PERIOD OF VFR BUT WILL LIKELY TAKE PLACE LATER IN THE AFTERNOON.
HOWEVER...THE IMPROVEMENT TO VFR WILL BE RELATIVELY SHORTLIVED IN
THE EVENING AS ANOTHER ROUND OF LOW CEILINGS AND VISIBILITIES IS
EXPECTED OVERNIGHT. MODEL OUTPUT DEPICTS CONSIDERABLE MOISTURE
STILL TRAPPED BENEATH THE NOCTURNAL INVERSION AND GUIDANCE IS
ADVERTISING IFR CEILINGS AND VISIBILITIES BEGINNING IN THE EARLY
MORNING HOURS AND CONTINUING THROUGH MID MORNING. I HAVE
INTRODUCED IFR CONDITIONS AT BOTH SITES AROUND 06Z...AND KEPT THEM
IN PLACE THROUGH 14Z. STRATUS BUILD DOWN OVERNIGHT MAY ACTUALLY
PRODUCE CEILINGS BELOW 500 FT AND VISIBILITIES BELOW 1 SM BUT JUST
WANTED TO TREND TO IFR FOR NOW.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS ARE POSSIBLE
AT BOTH TERMINALS SATURDAY NIGHT THROUGH SUNDAY MORNING DUE TO
SHOWERS AND THUNDERSTORMS THAT DEVELOP ALONG/AHEAD OF A COLD FRONT
PUSHING THROUGH THE AREA.
&&
.MARINE...
THERE ARE NO MARINE CONCERNS THROUGH TONIGHT. WINDS ARE EXPECTED
TO TURN MORE ONSHORE THIS AFTERNOON AS THE STALLED OUT FRONTAL
BOUNDARY GETS DRAGGED INLAND IN RESPONSE TO LOW PRESSURE
APPROACHING THE VALDOSTA AREA. WINDS WILL REMAIN 10 KT OR LESS
WITH SEAS 3 FT OR LESS.
A WEAK SFC LOW/SURFACE TROUGH WILL GRADUALLY LIFT NORTH ON FRIDAY
BEFORE AN ONSHORE FLOW DEVELOPS FRIDAY AFTERNOON. WINDS/SEAS WILL
THEN INCREASE/BUILD LATE FRIDAY INTO SATURDAY AS A LARGE LOW
PRESSURE SYSTEM APPROACHES THE SOUTHEASTERN UNITED STATES. SMALL
CRAFT ADVISORIES MAY BE NEEDED SATURDAY NIGHT THROUGH SUNDAY NIGHT
AS AN ENHANCED PRESSURE GRADIENT ASSOCIATED WITH THIS SYSTEM
SHIFTS OVER THE COASTAL WATERS. AT THIS TIME...WINDS WILL LIKELY
APPROACH 20 KNOTS FOR ALL WATERS WHILE SEAS BUILD TO 5-7 FEET FOR
WATERS BEYOND 15 NM FROM THE COAST. WINDS AND SEAS WILL QUICKLY
LOWER/SUBSIDE WITH COLD FROPA SUNDAY. WINDS AND SEAS WILL THEN
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS AS HIGH PRESSURE
BUILDS OVER THE WATERS EARLY NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...BSH
MARINE...DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1105 AM EDT THU APR 19 2012
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER NEAR THE AREA THROUGH FRIDAY.
A STRONG LOW PRESSURE SYSTEM WILL THEN AFFECT THE REGION THIS
WEEKEND FOLLOWED BY COOL AND DRY HIGH PRESSURE THROUGH THE MIDDLE
OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATE THIS MORNING...SURFACE ANALYSIS SHOWS THE FRONT LINGERING
JUST OFF THE SC/GA COAST WITH COOL NE FLOW IN PLACE ACROSS INLAND
LOCATIONS. ALOFT...A WEAK 500 MB PATTERN PERSISTS WITH A WEAK
SHORTWAVE APPROACHING FROM THE WEST NOTED IN WATER VAPOR IMAGERY.
THERE IS ALSO STILL QUITE A BIT OF DRY AIR IN THE UPPER LEVELS AS
SEEN IN THE 12Z SOUNDING. LOW OVERCAST STRATUS COVER THE FORECAST
AREA WITH MAINLY ISOLATED TO SCATTERED LIGHT RAIN SHOWERS. MOST OF
THE FORECAST CHALLENGES FOR TODAY HINGE GREATLY ON THE EVENTUAL
EVOLUTION OF THE LOW STRATUS AND THE IN-SITU WEDGE THAT IS IN
PLACE. AS IS USUALLY THE CASE...LARGER SCALE MODELS ARE SCOURING
OUT THE LOW CLOUDS AND THE WEDGE BY EARLY AFTERNOON AND ALLOWING
AT LEAST PARTIAL CLEARING TODAY. SHORTER RANGE MESOSCALE MODELS
SUCH AS THE LOCAL WRF AND HRRR AREN/T AS OPTIMISTIC...AND ALLOW
THE NE FLOW AND LOW CLOUDS TO HANG AROUND FOR JUST ABOUT THE
ENTIRE DAY. I HAVE FAVORED THE PESSIMISTIC SOLUTION WHICH HAS
RESULTED IN SOME ADJUSTMENTS TO THE GOING FORECAST. I HAVE COOLED
HIGHS TODAY BY SEVERAL DEGREES BASED ON BROKEN TO OVERCAST SKIES
STAYING IN PLACE THROUGH THE AFTERNOON. CURRENTLY TEMPS ARE RISING
VERY SLOWLY INTO THE LOW TO MID 60S...AND EVEN THOUGH LOW LEVEL
THICKNESS VALUES SUPPORT LOW 80S TODAY...I HAVE TAPERED TEMPS DOWN
INTO THE LOW TO MID 70S. AREAS ACROSS FAR SE GA STAND THE BEST
CHANCE OF SEEING SOME CLEARING...SO HIGHS IN THE UPPER 70S DOWN
AROUND DARIEN SEEM PLAUSIBLE. CONCERNING POPS...THE CURRENT SHOWER
COVERAGE IS DUE TO SOME ISENTROPIC LIFT AND WEAK UPPER ASCENT JUST
AHEAD OF THE APPROACHING SHORTWAVE. WITH MUCH COOLER SURFACE TEMPS
TODAY...COMBINED WITH MOIST PROFILES UP TO AROUND 600 MB AND WEAK
LAPSE RATES...ITS GOING TO BE DIFFICULT TO GET MUCH IF ANY
CONVECTION GOING THIS AFTERNOON. I HAVE MAINTAINED CHANCE POPS TO
ACCOUNT FOR SOME SHOWER ACTIVITY...BUT SHORT RANGE MODELS SUCH AS
THE HRRR SUPPORT VERY LITTLE IN THE WAY OF COVERAGE. WILL KEEP AN
EYE ON POP TRENDS FOR THE EARLY AFTERNOON UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...SCATTERED SHOWERS/TSTMS WILL QUICKLY WIND DOWN AFTER
SUNSET WITH THE LOSS OF INSOLATION AND WEAK NVA DEVELOPS IN THE
WAKE OF THE PASSING SHORTWAVE. ANY CLEARING THAT TOOK PLACE OVER
FAR SOUTHERN SOUTHEAST GEORGIA WILL QUICKLY GIVE WAY TO MOSTLY
CLOUDY SKIES AS LOW/MID-LEVEL CLOUDS FILL BACK IN. LOWS WILL RANGE
FROM THE UPPER 50S INLAND-LOWER 60S COAST.
FRIDAY...A WEAK SFC LOW/SURFACE TROUGH WILL LINGER OVER THE
FORECAST AREA EARLY BEFORE GRADUALLY LIFTING NORTH BY FRIDAY
AFTERNOON. ONSHORE FLOW WILL THEN DEVELOP AS WEAK HIGH PRESSURE
SLIDES OFF THE MID ATLANTIC COAST WHILE A LARGE AND DEEP LOW
DEVELOPS OVER THE NORTHERN GULF OF MEXICO. OVERALL HIGH TEMPS ARE
EXPECTED TO REACH THE LOW 80S WITH SOUTHERLY FLOW AND MODEST MID
LVL RIDGING AHEAD OF THE APPROACHING SYSTEM TO OUR WEST. DESPITE
RIDGING ALOFT...ENHANCED MOISTURE SHOULD PRODUCE A FEW SHOWERS AND
PERHAPS A FEW THUNDERSTORMS OVER THE AREA...ESPECIALLY ALONG AN
AFTERNOON SEABREEZE.
SATURDAY AND SUNDAY...A LARGE AND POTENTIALLY STRONG LOW PRESSURE
SYSTEM WILL AFFECT THE SOUTHEAST THIS WEEKEND. SEVERE WEATHER WILL
BE POSSIBLE WITH THIS SYSTEM BUT WILL BE HIGHLY DEPENDENT ON THE
TRACK AND TIMING OF A SFC LOW THAT DEVELOPS OVER THE NORTHERN GULF.
AT THIS TIME...A TROUGH OF LOW PRESSURE IS EXPECTED TO DIG OVER THE
CENTRAL UNITED STATES AND ENCOUNTER A STRONG SOUTHERN STREAM
JET...WHICH WILL AID IN THE DEVELOPMENT AND DEEPENING OF A SFC LOW
OVER THE NORTHERN GULF OF MEXICO. SEVERAL WEAK H5 SHORTWAVES WILL THEN
SHIFT AROUND AND AHEAD THE PERIPHERY OF THE DEEPENING LOW WHILE IT
SLOWLY PROGRESSES EAST. CHANCES OF SHOWERS/THUNDERSTORMS WILL
INCREASE TO LIKELY SATURDAY EVENING AS THESE H5 SHORTWAVES ENCOUNTER
AN INCREASINGLY MOIST BOUNDARY LAYER OVER THE SOUTHEASTERN UNITED
STATES. LATEST GUIDANCE SUGGESTS A MORE SOUTHERN TRACK OF THE SFC
LOW...WHICH WOULD SHIFT AN ENHANCED PERIOD OF SEVERE WEATHER SOUTH
OF THE FORECAST AREA. HOWEVER...SHOULD THE TRACK OF THE SFC LOW MAKE
A SLIGHT TREND NORTH...STRONG THUNDERSTORMS MAY BE POSSIBLE OVER
SOUTHEAST GEORGIA SOMETIME BETWEEN SATURDAY EVENING INTO SUNDAY
MORNING. PWATS BETWEEN 1.5 TO 2.0 INCHES ALSO SUGGEST THE POTENTIAL
FOR HEAVY RAINFALL...ESPECIALLY ALONG THE SOUTHEAST GEORGIA COAST.
DESPITE INCREASING CLOUD COVER...HIGH TEMPS WILL REACH THE LOW
80S...WITH WARMEST TEMPS OVER SOUTHEAST GEORGIA.
SHOWERS/THUNDERSTORMS WILL BE POSSIBLE THROUGH SUNDAY MORNING BEFORE
A COLD FRONT PASSES THROUGH THE FORECAST AREA. CONDITIONS SHOULD
THEN RAPIDLY IMPROVE SUNDAY AFTERNOON/EVENING AS HIGH PRESSURE
SETTLES OVER THE REGION BEHIND THE DEPARTING LOW. HAVE LOWERED POPS
TO LOW END CHANCE BY SUNDAY EVENING. OVERALL TEMPS WILL BE
COOLER...IN THE LOW/MID 70S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
COOL AND DRY CONDITIONS WILL BE IN PLACE THROUGH THE MIDDLE OF NEXT
WEEK AS SFC HIGH PRESSURE REMAINS OVER THE FORECAST AREA WHILE A
MID/UPPER LVL TROUGH SLOWLY DRIFTS OFF THE ATLANTIC SEABOARD.
OVERALL...HIGH TEMPS WILL BE IN THE MID 70S MONDAY/TUESDAY BEFORE
GRADUALLY WARMING INTO THE UPPER 70S/LOWER 80S BY LATE WEEK.
OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO MID 50S. DRY
CONDITIONS ARE EXPECTED TO PERSIST THROUGH LATE WEEK AS MID LVL
RIDGING EXPANDS OVER THE SOUTHEASTERN UNITED STATES.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
IFR CIGS WILL PERSIST FOR A FEW MORE HOURS...PERHAPS INTO THE
EARLY AFTERNOON. EVEN ONCE THEY IMPROVE...THE CURRENT THINKING IS
THAT MVFR WILL HOLD STRONG INTO THE AFTERNOON. WITH THE BKN TO OVC
STRATUS STICKING AROUND...THE OVERALL CONVECTIVE THREAT IS LOWER
FOR THIS AFTERNOON. HOWEVER...ISOLATED TO SCATTERED SHOWERS WILL
BE POSSIBLE. LOW CLOUDS ARE POSSIBLE AGAIN TONIGHT... MAINLY
AFTER 06Z WITH THE POTENTIAL FOR SOME REDUCED VSBYS FROM STRATUS
BUILD DOWN.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS ARE POSSIBLE
AT BOTH TERMINALS SATURDAY NIGHT THROUGH SUNDAY MORNING DUE TO
SHOWERS AND THUNDERSTORMS THAT DEVELOP ALONG/AHEAD OF A COLD FRONT
PUSHING THROUGH THE AREA.
&&
.MARINE...
THERE ARE NO MARINE CONCERNS THROUGH TONIGHT. WINDS ARE EXPECTED
TO TURN MORE ONSHORE THIS AFTERNOON AS THE STALLED OUT FRONTAL
BOUNDARY GETS DRAGGED INLAND IN RESPONSE TO LOW PRESSURE
APPROACHING THE VALDOSTA AREA. WINDS WILL REMAIN 10 KT OR LESS
WITH SEAS 3 FT OR LESS.
A WEAK SFC LOW/SURFACE TROUGH WILL GRADUALLY LIFT NORTH ON FRIDAY
BEFORE AN ONSHORE FLOW DEVELOPS FRIDAY AFTERNOON. WINDS/SEAS WILL
THEN INCREASE/BUILD LATE FRIDAY INTO SATURDAY AS A LARGE LOW
PRESSURE SYSTEM APPROACHES THE SOUTHEASTERN UNITED STATES. SMALL
CRAFT ADVISORIES MAY BE NEEDED SATURDAY NIGHT THROUGH SUNDAY NIGHT
AS AN ENHANCED PRESSURE GRADIENT ASSOCIATED WITH THIS SYSTEM
SHIFTS OVER THE COASTAL WATERS. AT THIS TIME...WINDS WILL LIKELY
APPROACH 20 KNOTS FOR ALL WATERS WHILE SEAS BUILD TO 5-7 FEET FOR
WATERS BEYOND 15 NM FROM THE COAST. WINDS AND SEAS WILL QUICKLY
LOWER/SUBSIDE WITH COLD FROPA SUNDAY. WINDS AND SEAS WILL THEN
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS AS HIGH PRESSURE
BUILDS OVER THE WATERS EARLY NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BSH
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...BSH
MARINE...DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
355 AM EDT THU APR 19 2012
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER NEAR THE AREA THROUGH FRIDAY.
A STRONG LOW PRESSURE SYSTEM WILL THEN AFFECT THE REGION THIS
WEEKEND FOLLOWED BY COOL AND DRY HIGH PRESSURE THROUGH THE MIDDLE
OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
19/07Z MESOANALYSIS SHOWED A STATIONARY FRONT POSITIONED JUST
OFF THE SOUTH CAROLINA AND GEORGIA COASTS...CONNECTED BETWEEN WEAK
LOW PRESSURE NEAR CAPE FEAR AND A SECONDARY LOW OVER THE FLORIDA
PANHANDLE. PATCHY...MAINLY LIGHT SHOWERS ARE SLOWLY SPREADING
INLAND EARLY THIS MORNING AHEAD OF A WELL DEFINED H8 VORTICITY
MAXIMUM SPINNING OVER SOUTHWEST GEORGIA. WATER VAPOR IMAGERY
INFERS THIS ACTIVITY IS BEING SUPPORTED BY AN AXIS OF MID-LEVEL
DEFORMATION EXTENDING EAST FROM THE VORT CENTER ACROSS CENTRAL
GEORGIA INTO INTERIOR SOUTHEAST SOUTH CAROLINA. SUSPECT THIS
LIFTING MECHANISM WILL CONTINUE TO ENHANCE THE RISK FOR SHOWER
ACTIVITY ACROSS MAINLY THE INTERIOR THROUGH SUNRISE...THUS WILL
HIGHLIGHT CHANCE POPS UP TO 40 PERCENT IN THESE AREAS FOR THE NEXT
SEVERAL HOURS. THE ATMOSPHERE LOOKS FAIRLY STABLE OVER LAND AREAS
PER RUC POINT SOUNDINGS...BUT AN ISOLATED RUMBLE OR TWO OF THUNDER
CAN NOT BE COMPLETELY RULED OUT.
SHORTWAVE ENERGY MOVING ACROSS THE SOUTHERN MISSISSIPPI VALLEY
THIS MORNING WILL PROPAGATE QUICKLY EAST...CROSSING SOUTHERN
GEORGIA BY LATE AFTERNOON. LOW PRESSURE CURRENTLY DEVELOPING ACROSS
THE FLORIDA PANHANDLE ALONG THE STALLED FRONTAL BOUNDARY WILL
SLOWLY STRENGTHEN/CONSOLIDATE AS THE SHORTWAVE APPROACHES.
MODELS SHOW THE CYCLONE MOVING TO NEAR THE VALDOSTA AREA BY EARLY
AFTERNOON WHICH WILL HELP DRAG THE STALLED FRONTAL BOUNDARY BACK
INLAND ACROSS MAINLY SOUTHEAST GEORGIA AS THE DAY PROGRESSES.
MEANWHILE...AN IN-SITU WEDGE IS EXPECTED RAPIDLY MATURE ACROSS THE
SOUTH CAROLINA MIDLANDS LATER THIS MORNING IN RESPONSE TO MAINLY
LIGHT SHOWER ACTIVITY FALLING NORTH OF THE STALLED FRONT WHERE
DIABATIC PROCESSES WILL BE MAXIMIZED. THIS WILL MAKE FOR AN
EXTREMELY CHALLENGING TEMPERATURE FORECAST DURING THE AFTERNOON
HOURS WITH THE STALLED FRONT ESSENTIALLY BISECTING MUCH OF
SOUTHEAST GEORGIA ROUGHLY ALONG THE I-16 CORRIDOR AND BENDING
NORTH ALONG THE LOWER SOUTH CAROLINA COAST.
GENERALLY PREFER THE NAM/S HIGHER RESOLUTION PLACEMENT OF THE
VARIOUS THERMAL GRADIENTS AND WAS USED AS THE PRIMARY BLENDING
VARIABLE FOR THE CONSTRUCTION OF TODAY/S HIGH TEMPERATURE
FORECAST. EXPECT HIGHS TO RANGE FROM THE LOWER 70S ACROSS INTERIOR
SOUTHEAST SOUTH CAROLINA TO THE LOWER 80S SOUTH OF INTERSTATE 16.
IT IS VERY POSSIBLE THAT AREAS BORDERING THE SOUTHERN MIDLANDS AND
CSRA SUCH AS ALLENDALE-SMOAKS-SAINT GEORGE AND SAINT STEPHENS
COULD STRUGGLE TO REACH 70 DEGREES IF ENOUGH LIGHT RAIN FALLS IN
THE CORE OF THE WEDGE TODAY. FURTHER REFINEMENTS TO THE HIGH
TEMPERATURE FORECAST WILL MOST CERTAINLY BE MADE AS THE DAY
PROGRESSES.
A RISK FOR SHOWER/TSTM ACTIVITY WILL PERSIST THROUGH MUCH OF THE
DAY TODAY WITH THE STALLED FRONTAL BOUNDARY LINGERING IN THE
VICINITY AND SYNOPTIC LIFT INCREASING AHEAD OF THE APPROACHING
SOUTHERN STREAM SHORTWAVE. THE VARIOUS HIGH RESOLUTION PACKAGES
ARE SIMILAR IN DEPICTING CONVECTION BECOMING CONCENTRATED NORTH OF
THE STALLED FRONT THIS AFTERNOON ROUGHLY WITHIN THE WALTERBORO-
NORTH CHARLESTON-MONCKS CORNER CORRIDOR. THIS APPEARS TO BE WHERE
A LINGERING POOL OF MID-LEVEL THETA-E BECOMES MAXIMIZED BETWEEN
DPVA/UVV INDUCED BY THE SHORTWAVE ITSELF AND A REGION OF WEAKLY
ENHANCED 250MB DIVERGENCE ASSOCIATED WITH THE RRQ OF A 50-60 KT
JET STREAK. PLAN TO STICK WITH CHANCE POPS ALL AREAS TODAY WITH
POPS RANGING FROM 30-50 PERCENT--HIGHEST ACROSS INTERIOR
SOUTHEAST SOUTH CAROLINA IN THE AFOREMENTIONED CORRIDOR. NAM/RUC
INSTABILITY PLOTS SUGGEST SCATTERED TSTMS WILL BE POSSIBLE...SOME
OF WHICH COULD BECOME SOMEWHAT ELEVATED NORTH OF THE FRONT. AN
ISOLATED STRONG OR PERHAPS SEVERE TSTM CAN NOT BE RULED OUT SOUTH
OF I-16 WHERE DCAPES ARE PROGGED TO REACH AS HIGH AS 800-1000 J/KG
COUPLED WITH SBCAPES NEARING 2000 J/KG. THE RISK MAY BECOME
LOCALLY ENHANCED NEAR THE ALTAMAHA RIVER BY MID-LATE AFTERNOON
SHOULD SOME CLEARING OCCUR AS NOTED IN SOME OF THE SHORT RANGE
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
TONIGHT...SCATTERED SHOWERS/TSTMS WILL QUICKLY WIND DOWN AFTER
SUNSET WITH THE LOSS OF INSOLATION AND WEAK NVA DEVELOPS IN THE
WAKE OF THE PASSING SHORTWAVE. ANY CLEARING THAT TOOK PLACE OVER
FAR SOUTHERN SOUTHEAST GEORGIA WILL QUICKLY GIVE WAY TO MOSTLY
CLOUDY SKIES AS LOW/MID-LEVEL CLOUDS FILL BACK IN. LOWS WILL RANGE
FROM THE UPPER 50S INLAND-LOWER 60S COAST.
FRIDAY...A WEAK SFC LOW/SURFACE TROUGH WILL LINGER OVER THE
FORECAST AREA EARLY BEFORE GRADUALLY LIFTING NORTH BY FRIDAY
AFTERNOON. ONSHORE FLOW WILL THEN DEVELOP AS WEAK HIGH PRESSURE
SLIDES OFF THE MID ATLANTIC COAST WHILE A LARGE AND DEEP LOW
DEVELOPS OVER THE NORTHERN GULF OF MEXICO. OVERALL HIGH TEMPS ARE
EXPECTED TO REACH THE LOW 80S WITH SOUTHERLY FLOW AND MODEST MID
LVL RIDGING AHEAD OF THE APPROACHING SYSTEM TO OUR WEST. DESPITE
RIDGING ALOFT...ENHANCED MOISTURE SHOULD PRODUCE A FEW SHOWERS AND
PERHAPS A FEW THUNDERSTORMS OVER THE AREA...ESPECIALLY ALONG AN
AFTERNOON SEABREEZE.
SATURDAY AND SUNDAY...A LARGE AND POTENTIALLY STRONG LOW PRESSURE
SYSTEM WILL AFFECT THE SOUTHEAST THIS WEEKEND. SEVERE WEATHER WILL
BE POSSIBLE WITH THIS SYSTEM BUT WILL BE HIGHLY DEPENDENT ON THE
TRACK AND TIMING OF A SFC LOW THAT DEVELOPS OVER THE NORTHERN GULF.
AT THIS TIME...A TROUGH OF LOW PRESSURE IS EXPECTED TO DIG OVER THE
CENTRAL UNITED STATES AND ENCOUNTER A STRONG SOUTHERN STREAM
JET...WHICH WILL AID IN THE DEVELOPMENT AND DEEPENING OF A SFC LOW
OVER THE NORTHERN GULF OF MEXICO. SEVERAL WEAK H5 SHORTWAVES WILL THEN
SHIFT AROUND AND AHEAD THE PERIPHERY OF THE DEEPENING LOW WHILE IT
SLOWLY PROGRESSES EAST. CHANCES OF SHOWERS/THUNDERSTORMS WILL
INCREASE TO LIKELY SATURDAY EVENING AS THESE H5 SHORTWAVES ENCOUNTER
AN INCREASINGLY MOIST BOUNDARY LAYER OVER THE SOUTHEASTERN UNITED
STATES. LATEST GUIDANCE SUGGESTS A MORE SOUTHERN TRACK OF THE SFC
LOW...WHICH WOULD SHIFT AN ENHANCED PERIOD OF SEVERE WEATHER SOUTH
OF THE FORECAST AREA. HOWEVER...SHOULD THE TRACK OF THE SFC LOW MAKE
A SLIGHT TREND NORTH...STRONG THUNDERSTORMS MAY BE POSSIBLE OVER
SOUTHEAST GEORGIA SOMETIME BETWEEN SATURDAY EVENING INTO SUNDAY
MORNING. PWATS BETWEEN 1.5 TO 2.0 INCHES ALSO SUGGEST THE POTENTIAL
FOR HEAVY RAINFALL...ESPECIALLY ALONG THE SOUTHEAST GEORGIA COAST.
DESPITE INCREASING CLOUD COVER...HIGH TEMPS WILL REACH THE LOW
80S...WITH WARMEST TEMPS OVER SOUTHEAST GEORGIA.
SHOWERS/THUNDERSTORMS WILL BE POSSIBLE THROUGH SUNDAY MORNING BEFORE
A COLD FRONT PASSES THROUGH THE FORECAST AREA. CONDITIONS SHOULD
THEN RAPIDLY IMPROVE SUNDAY AFTERNOON/EVENING AS HIGH PRESSURE
SETTLES OVER THE REGION BEHIND THE DEPARTING LOW. HAVE LOWERED POPS
TO LOW END CHANCE BY SUNDAY EVENING. OVERALL TEMPS WILL BE
COOLER...IN THE LOW/MID 70S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
COOL AND DRY CONDITIONS WILL BE IN PLACE THROUGH THE MIDDLE OF NEXT
WEEK AS SFC HIGH PRESSURE REMAINS OVER THE FORECAST AREA WHILE A
MID/UPPER LVL TROUGH SLOWLY DRIFTS OFF THE ATLANTIC SEABOARD.
OVERALL...HIGH TEMPS WILL BE IN THE MID 70S MONDAY/TUESDAY BEFORE
GRADUALLY WARMING INTO THE UPPER 70S/LOWER 80S BY LATE WEEK.
OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO MID 50S. DRY
CONDITIONS ARE EXPECTED TO PERSIST THROUGH LATE WEEK AS MID LVL
RIDGING EXPANDS OVER THE SOUTHEASTERN UNITED STATES.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
LIGHT SHOWER ACTIVITY IS POSSIBLE AT EITHER KCHS/KSAV THROUGH
SUNRISE. NO SIGNIFICANT REDUCTIONS IN VSBYS ARE EXPECTED. LOW CIGS
ARE PROGGED TO REMAIN IN TACT FOR SEVERAL MORE HOURS BEFORE SOME
IMPROVEMENT OCCURS. SHOULD SEE A RETURN TO VFR AT BOTH TERMINALS
BY MID-MORNING ALTHOUGH CLOUDY CONDITIONS WILL PERSIST.
SHOWER/TSTM ACTIVITY IS FORECAST TO REDEVELOP INLAND LATER THIS
MORNING AND INTO THE AFTERNOON AS A WEAK FRONTAL BOUNDARY LINGERS
NEAR THE COAST. HIGH RESOLUTION DATA SETS SUGGEST IMPACTS ARE
HIGHEST AT KCHS SO WILL CARRY MARGINAL MVFR CONDITIONS IN SHOWERS
THERE FROM 17-21Z. ADJUSTMENTS...POSSIBLY INCLUDING TSRA...WILL
LIKELY BE NEEDED LATER THIS MORNING. WILL KEEP SHRA/TSRA OUT OF
KSAV FOR NOW. THERE ARE INDICATIONS THAT LOW CLOUDS COULD FILL
BACK IN LATER THIS EVENING...BUT CONFIDENCE IS NOT HIGH ENOUGH AT
THIS JUNCTURE TO INCLUDE A MENTION AT EITHER TERMINAL.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS ARE POSSIBLE
AT BOTH TERMINALS SATURDAY NIGHT THROUGH SUNDAY MORNING DUE TO
SHOWERS AND THUNDERSTORMS THAT DEVELOP ALONG/AHEAD OF A COLD FRONT
PUSHING THROUGH THE AREA.
&&
.MARINE...
THERE ARE NO MARINE CONCERNS THROUGH TONIGHT. WINDS ARE EXPECTED
TO TURN MORE ONSHORE THIS AFTERNOON AS THE STALLED OUT FRONTAL
BOUNDARY GETS DRAGGED INLAND IN RESPONSE TO LOW PRESSURE
APPROACHING THE VALDOSTA AREA. WINDS WILL REMAIN 10 KT OR LESS
WITH SEAS 3 FT OR LESS.
A WEAK SFC LOW/SURFACE TROUGH WILL GRADUALLY LIFT NORTH ON FRIDAY
BEFORE AN ONSHORE FLOW DEVELOPS FRIDAY AFTERNOON. WINDS/SEAS WILL
THEN INCREASE/BUILD LATE FRIDAY INTO SATURDAY AS A LARGE LOW
PRESSURE SYSTEM APPROACHES THE SOUTHEASTERN UNITED STATES. SMALL
CRAFT ADVISORIES MAY BE NEEDED SATURDAY NIGHT THROUGH SUNDAY NIGHT
AS AN ENHANCED PRESSURE GRADIENT ASSOCIATED WITH THIS SYSTEM
SHIFTS OVER THE COASTAL WATERS. AT THIS TIME...WINDS WILL LIKELY
APPROACH 20 KNOTS FOR ALL WATERS WHILE SEAS BUILD TO 5-7 FEET FOR
WATERS BEYOND 15 NM FROM THE COAST. WINDS AND SEAS WILL QUICKLY
LOWER/SUBSIDE WITH COLD FROPA SUNDAY. WINDS AND SEAS WILL THEN
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS AS HIGH PRESSURE
BUILDS OVER THE WATERS EARLY NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...DPB
AVIATION...
MARINE...DPB/
AREA FORECAST DISCUSSION
NWS LINCOLN IL
258 PM CDT THU APR 19 2012
.DISCUSSION...
ISSUED 258 PM CDT THU APR 19 2012
MODELS IN GOOD AGREEMENT WITH OVERALL SFC FEATURES AND UPPER LEVEL
PATTERN THROUGH SAT. AGREEMENT WITH SFC FEATURES FOR SAT NIGHT AND
SUNDAY GET MUDDIED AS A WEAK SFC LOW DROPS DOWN IN THE NORTHWEST
FLOW...PINCHING OFF SOME OF THE HIGH PRSS RIDGE. WITH MAIN FOCUS
BEING THE WEATHER SYSTEM FORECAST TO MOVE ACROSS THE AREA TONIGHT
THROUGH EARLY TOMORROW...BLEND OF THE MODELS LOOKS LIKE A GOOD
FORECAST...EVEN INTO THE WEEKEND...WITH DRY WEATHER.
EXTENDED MODELS IN GOOD AGREEMENT EARLY ON...BUT BEGIN TO DIFFER
TOWARD MIDDLE OF THE WEEK WITH TIMING OF NEXT CHANCE OF PCPN AND
LOCATION/DEEPNESS OF A TROUGH IN THE EAST.
SHORT TERM...TONIGHT THROUGH SUNDAY
CURRENTLY A STATIONARY FRONT IS LOCATED ACROSS NORTHERN IL...NEAR
I-80...THIS AFTERNOON WITH A SFC LOW IN NORTHEASTERN KS AND A
TRAILING COLD FRONT INTO OK AND TX. THE STATIONARY FRONT WILL
REMAIN NORTH OF THE AREA AS THE LOW AND COLD FRONT MOVE EAST-
NORTHEAST NEXT 24HRS. PCPN WILL REMAIN NORTH OF THE STATIONARY
FRONT...AND ALONG AND BEHIND THE COLD FRONT. THIS COLD FRONT WILL
MOVE THROUGH THE CWA LATE TONIGHT...AFTER 06Z...AND BRING SHOWERS
TO THE AREA FROM LATE TONIGHT THROUGH TOMORROW MORNING. NAM HAS
LESS PCPN THAN GFS...BUT SHOULD BE PLENTY OF MOISTURE FOR SHOWERS
BEGINNING LATE TONIGHT IN THE WEST AND THEN ADVECTING EASTWARD
DURING THE EARLY MORNING HOURS FRIDAY. PCPN WILL CONTINUE IN THE
SOUTHEAST DURING THE MORNING HOURS...BUT SHOULD BE OUT OF THE CWA
BY AFTERNOON. THEN DRY WEATHER IS EXPECTED REMAINDER OF THE SHORT
TERM PERIOD THROUGH SUNDAY. GUSTY WINDS WILL BE POSSIBLE BEHIND
THE FRONT TOMORROW BUT DIMINISH TOMORROW NIGHT...AND BE LIGHTER
THROUGH SUNDAY.
TEMPERATURES SHOULD BE FALLING TONIGHT AND STAY ON THE COOLER SIDE
TOMORROW BEHIND THE FRONT. MOS GUIDANCE LOOKS GOOD WITH RESPECT TO
COOLER TEMPS TOMORROW...EXCEPT FOR THE SOUTHEAST. TEMPS WILL BEGIN
TO MODERATE BACK UP FOR THE WEEKEND BUT REMAIN BELOW NORMAL SAT
AND SUNDAY.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
HIGH PRSS WILL SLOWLY BUILD INTO THE AREA FOR FIRST HALF OF THE
WEEK WITH DRY WEATHER AND TEMPS SLOWLY WARMING BACK TO ABOVE
NORMAL BY MIDDLE OF THE WEEK. ANOTHER WEATHER SYSTEM BEGINS TO
DROP TO THE AREA MIDDLE OF THE WEAK...BUT THIS SYSTEM LOOKS WEAK
AND MAY NOT HAVE A LOT OF MOISTURE. ECMWF AND GFS DIFFER ON
LOCATION AND AMOUNT OF PCPN DURING THE WED TO WED NIGHT TIME
PERIOD SO WILL JUST HAVE LOW CHANCES OF PCPN IN PARTS OF THE CWA
DURING THAT PERIOD.
TEMPS WILL WARM UP AS MID LEVEL RIDGE BUILDS INTO THE AREA OVER
THE PERIOD. GUIDANCE NUMBERS APPEAR LITTLE WARM MID WEEK...SO
TEMPS LITTLE COOLER IN FORECAST.
AUTEN
&&
.AVIATION...
ISSUED 1225 PM CDT THU APR 19 2012
AREA OF THUNDERSTORMS FROM NEAR KDSM-KMKC SHOWING SOME WEAKENING
WITH TIME. HRRR INDICATING SOME SHOWERS POSSIBLE AS FAR EAST AS
KPIA/KBMI LATE AFTERNOON AND EARLY EVENING. HAVE ADDED A FEW HOURS
OF VCSH AT THESE SITES...BUT CONFIDENCE IN THUNDERSTORM POTENTIAL
IS LOW ENOUGH TO PRECLUDE MENTION AT THIS TIME.
GUSTY SOUTH WINDS IN EXCESS OF 20 KNOTS TO CONTINUE THIS AFTERNOON
INTO EARLY TONIGHT. A COLD FRONT IS EXPECTED TO PUSH ACROSS THE
TAF SITES LATE TONIGHT AND EARLY FRIDAY MORNING...GENERALLY IN THE
09-15Z TIME FRAME...SWINGING WINDS AROUND TO THE NORTHWEST. WILL
SEE SOME SCATTERED SHOWERS WITH THIS FRONT...BUT INSTABILITY LOOKS
LOW ENOUGH THAT THUNDER IS NOT A CONCERN AT THIS TIME. FORECAST
SOUNDINGS INDICATE THAT MVFR CEILINGS ARE LIKELY FOR SEVERAL HOURS
FOLLOWING THE PASSAGE OF THE FRONT.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1225 PM CDT THU APR 19 2012
.DISCUSSION...
ISSUED 945 AM CDT THU APR 19 2012
FRONTAL BOUNDARY CURRENTLY CENTERED ROUGHLY ALONG THE I-80
CORRIDOR IN NORTHERN ILLINOIS AND SOUTHERN IOWA LATE THIS
MORNING. HAVE SEEN SOME ELEVATED CONVECTION NEAR THE WISCONSIN
BORDER...BUT MOST OF THE SHOWER/THUNDERSTORM ACTIVITY HAS BEEN
ADVANCING NORTHEASTWARD ACROSS IOWA AND NORTHWEST MISSOURI. THE
BULK OF THIS PRECIPITATION SHOULD MISS OUR FORECAST AREA...
ALTHOUGH THE HRRR MODEL IS A LITTLE MORE AMBITIOUS WITH BRINGING
SHOWERS/STORMS INTO AREAS NORTHWEST OF THE ILLINOIS RIVER BY MID
AFTERNOON. EXISTING 20-30 PERCENT RAIN CHANCES ACROSS THE
NORTHWEST SHOULD BE SUFFICIENT TO ADDRESS THIS CONCERN.
THE FRONT SHOULD MAKE A BIT OF A SOUTHWARD PUSH TODAY BUT STAY
WELL TO OUR NORTH. WITH A FAIR AMOUNT OF SUNSHINE...CURRENT
FORECAST OF HIGHS IN THE MID TO UPPER 70S LOOKS GOOD.
HAVE SENT SOME NEW GRIDDED FORECASTS TO UPDATE HOURLY TRENDS...
BUT NO CHANGE IS NEEDED TO THE WORDED FORECASTS AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 1225 PM CDT THU APR 19 2012
AREA OF THUNDERSTORMS FROM NEAR KDSM-KMKC SHOWING SOME WEAKENING
WITH TIME. HRRR INDICATING SOME SHOWERS POSSIBLE AS FAR EAST AS
KPIA/KBMI LATE AFTERNOON AND EARLY EVENING. HAVE ADDED A FEW HOURS
OF VCSH AT THESE SITES...BUT CONFIDENCE IN THUNDERSTORM POTENTIAL
IS LOW ENOUGH TO PRECLUDE MENTION AT THIS TIME.
GUSTY SOUTH WINDS IN EXCESS OF 20 KNOTS TO CONTINUE THIS AFTERNOON
INTO EARLY TONIGHT. A COLD FRONT IS EXPECTED TO PUSH ACROSS THE
TAF SITES LATE TONIGHT AND EARLY FRIDAY MORNING...GENERALLY IN THE
09-15Z TIME FRAME...SWINGING WINDS AROUND TO THE NORTHWEST. WILL
SEE SOME SCATTERED SHOWERS WITH THIS FRONT...BUT INSTABILITY LOOKS
LOW ENOUGH THAT THUNDER IS NOT A CONCERN AT THIS TIME. FORECAST
SOUNDINGS INDICATE THAT MVFR CEILINGS ARE LIKELY FOR SEVERAL HOURS
FOLLOWING THE PASSAGE OF THE FRONT.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT THU APR 19 2012
SHORT TERM...TODAY THROUGH SATURDAY
FRONTAL BOUNDARY WILL REMAIN DRAPED ACROSS NORTHERN ILLINOIS
TODAY...FOCUSING THE BEST RAIN CHANCES ALONG AND NORTH OF THE I-80
CORRIDOR. FURTHER SOUTH...SOME OF THE HIGH-RES MODELS SUGGEST THE
FAR NORTHERN KILX CWA MAY GET BRUSHED BY A FEW SHOWERS...PARTICULARLY
DURING THE MORNING HOURS. BOUNDARY MAY GET PUSHED A BIT FURTHER
NORTHWARD THIS AFTERNOON AS LOW PRESSURE DEVELOPING OVER THE
PLAINS BEGINS TO TRACK EASTWARD. AS A RESULT...HAVE INCLUDED LOW
CHANCE POPS FROM THE PEORIA AREA NORTHWARD...WITH DRY CONDITIONS
EXPECTED ELSEWHERE. MAIN STORY TODAY WILL BE THE BREEZY AND WARM
WEATHER. WITH PARTIAL SUNSHINE AND SOUTHERLY WINDS GUSTING TO
AROUND 25 MPH AT TIMES...AFTERNOON HIGH TEMPS WILL SOAR WELL INTO
THE 70S.
SHORT-WAVE TROUGH CURRENTLY CROSSING THE ROCKIES WILL APPROACH
FROM THE WEST TONIGHT. THIS WILL GIVE THE STALLED FRONTAL BOUNDARY
A PUSH TO THE EAST AND SOUTH...GRADUALLY SPREADING RAIN CHANCES
INTO CENTRAL ILLINOIS OVERNIGHT. 00Z 19 APR MODELS HAVE CONTINUED
TO SLOW THE EASTWARD PROGRESS OF THE SYSTEM...WITH ALL MODELS NOW
KEEPING THE FAR E/SE CWA DRY THROUGH THE NIGHT. IN ADDITION...THE
LATEST MODEL RUN HAS ALSO CONSIDERABLY REDUCED THE EXPECTED QPF.
THIS SEEMS REASONABLE BASED ON 00Z UPPER AIR ANALYSIS SHOWING
LOW-LEVEL RIDGING BLOCKING NORTHWARD MOISTURE TRANSPORT FROM THE
GULF OF MEXICO. ONLY A NARROW RIBBON OF 850MB MOISTURE WAS NOTED
FROM THE SOUTHERN PLAINS INTO THE UPPER MIDWEST...WHILE THE DEEPEST
MOISTURE REMAINS LOCKED UP WELL TO THE E/SE ACROSS FLORIDA.
SURFACE DEWPOINTS ALSO REFLECT A GENERAL LACK OF MOISTURE...WITH
UPSTREAM VALUES ACROSS TEXAS/OKLAHOMA ONLY IN THE UPPER 40S AND
LOWER 50S. DUE TO MEAGER MOISTURE RETURN...NAM FEATURES ONLY A
THIN PLUME OF INSTABILITY DEVELOPING AHEAD OF THE APPROACHING
WAVE ACROSS THE PLAINS THIS AFTERNOON...WHICH THEN QUICKLY
DIMINISHES AS IT MOVES FURTHER EASTWARD AFTER SUNSET. HAVE
THEREFORE REMOVED THUNDER MENTION FROM THE FORECAST TONIGHT AND
FRIDAY. HAVE ALSO SPED UP THE DEPARTURE OF THE PRECIP...WITH THE
NAM/GFS/ECMWF ALL INDICATING A NARROW BAND OF MAINLY POST-FRONTAL
SHOWERS WITH PERHAPS A FEW EMBEDDED THUNDERSTORMS EXITING INTO
INDIANA BY EARLY FRIDAY EVENING. HAVE CARRIED LIKELY POPS
ALONG/WEST OF I-55 TONIGHT...THEN EAST OF I-55 FRIDAY MORNING.
RAIN CHANCES WILL THEN BEGIN TO DIMINISH FROM WEST TO EAST ACROSS
THE AREA FRIDAY AFTERNOON...WITH ONLY A FEW LINGERING SHOWERS
ACROSS THE FAR SE BY FRIDAY EVENING.
MUCH COOLER AIRMASS WILL FILTER INTO THE REGION FRIDAY NIGHT INTO
SATURDAY...WITH LOW TEMPS DROPPING INTO THE UPPER 30S/LOWER 40S
FRIDAY NIGHT AND HIGHS ONLY RECOVERING INTO THE 50S ON SATURDAY.
COLDEST NIGHT OF THE FORECAST PERIOD APPEARS TO BE SATURDAY
NIGHT...WHEN LOWS WILL DIP INTO THE MIDDLE TO UPPER 30S. FROST MAY
BE POSSIBLE EARLY SUNDAY MORNING...ALTHOUGH AN UPPER WAVE DIVING
SOUTHEASTWARD OUT OF THE NORTHERN PLAINS MAY PROVIDE ENOUGH
MID/HIGH CLOUD COVER TO KEEP IT FROM BECOMING A PROBLEM. WILL KEEP
FROST MENTION OUT OF THE FORECAST FOR NOW...UNTIL SKY COVER/WIND
DETAILS BECOME A BIT CLEARER.
LONG TERM...SUNDAY THROUGH WEDNESDAY
MODELS CONTINUE TO ADVERTISE A DEEP UPPER TROUGH DEVELOPING OVER
THE EASTERN CONUS EARLY NEXT WEEK...ALTHOUGH THE SPEED OF ITS
EVENTUAL DEPARTURE STILL REMAINS IN QUESTION. 00Z ECMWF IS THE
DEEPEST AND SLOWEST WITH THIS SYSTEM...KEEPING IT IN PLACE ACROSS
NEW ENGLAND AT LEAST THROUGH WEDNESDAY. MEANWHILE...GFS IS THE
MOST PROGRESSIVE...TAKING THE UPPER LOW INTO EASTERN CANADA AS
EARLY AS TUESDAY. CANADIAN REPRESENTS A MIDDLE-OF-THE-ROAD
SOLUTION AND WAS PREFERRED FOR THIS FORECAST PACKAGE. END RESULT
WILL BE COOL/DRY WEATHER FOR SUNDAY AND MONDAY...FOLLOWED BY A
GRADUAL WARMING TREND BY THE MIDDLE OF THE WEEK. HIGH TEMPS WILL
START OUT IN THE UPPER 50S/LOWER 60S ON SUNDAY...THEN WILL CLIMB
WELL INTO THE 70S BY WEDNESDAY.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
946 AM CDT THU APR 19 2012
.DISCUSSION...
ISSUED 945 AM CDT THU APR 19 2012
FRONTAL BOUNDARY CURRENTLY CENTERED ROUGHLY ALONG THE I-80
CORRIDOR IN NORTHERN ILLINOIS AND SOUTHERN IOWA LATE THIS
MORNING. HAVE SEEN SOME ELEVATED CONVECTION NEAR THE WISCONSIN
BORDER...BUT MOST OF THE SHOWER/THUNDERSTORM ACTIVITY HAS BEEN
ADVANCING NORTHEASTWARD ACROSS IOWA AND NORTHWEST MISSOURI. THE
BULK OF THIS PRECIPITATION SHOULD MISS OUR FORECAST AREA...
ALTHOUGH THE HRRR MODEL IS A LITTLE MORE AMBITIOUS WITH BRINGING
SHOWERS/STORMS INTO AREAS NORTHWEST OF THE ILLINOIS RIVER BY MID
AFTERNOON. EXISTING 20-30 PERCENT RAIN CHANCES ACROSS THE
NORTHWEST SHOULD BE SUFFICIENT TO ADDRESS THIS CONCERN.
THE FRONT SHOULD MAKE A BIT OF A SOUTHWARD PUSH TODAY BUT STAY
WELL TO OUR NORTH. WITH A FAIR AMOUNT OF SUNSHINE...CURRENT
FORECAST OF HIGHS IN THE MID TO UPPER 70S LOOKS GOOD.
HAVE SENT SOME NEW GRIDDED FORECASTS TO UPDATE HOURLY TRENDS...
BUT NO CHANGE IS NEEDED TO THE WORDED FORECASTS AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 610 AM CDT THU APR 19 2012
VFR CONDITIONS ARE EXPECTED THROUGH 09Z WITH LOW VFR CIGS SHIFTING
SE ACRS THE NORTH IN THE 09Z-12Z TIME FRAME. A FRONTAL BOUNDARY
JUST NORTH OF I-80 WILL REMAIN NORTH OF OUR AREA TODAY WHILE LOW
PRESSURE TRACKS NE INTO IOWA. MOST IF NOT ALL THE PRECIP ASSOCIATED
WITH THIS STORM SYSTEM WILL BE OCCURRING ALONG AND NORTH OF THE
BOUNDARY. OUR RAIN CHANCES START TO INCREASE LATER TONIGHT AS THE
FRONT SHIFTS INTO WEST CENTRAL IL. UNTIL THEN...OTHER THAN SOME
MID AND HIGH CLOUDS...NO SIGNIFICANT WEATHER IS EXPECTED ACRS OUR
AREA TODAY. ABOUT THE ONLY CONCERN WILL BE WITH THE GUSTY SOUTH
WINDS TODAY WITH SPEEDS AVERAGING FROM 15 TO 20 KTS...WITH OCCASIONAL
GUSTS AROUND 25 KTS. LOOK FOR THE WINDS TO VEER MORE INTO A SOUTHWEST
DIRECTION LATE TONIGHT AT PIA AS THE FRONT APPROACHES. LOOKS LIKE
FROPA AT PIA WILL OCCUR AROUND 12Z FRIDAY..AND LATER FRIDAY MORNING
ACRS THE REMAINDER OF THE TAF SITES.
SMITH
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT THU APR 19 2012
SHORT TERM...TODAY THROUGH SATURDAY
FRONTAL BOUNDARY WILL REMAIN DRAPED ACROSS NORTHERN ILLINOIS
TODAY...FOCUSING THE BEST RAIN CHANCES ALONG AND NORTH OF THE I-80
CORRIDOR. FURTHER SOUTH...SOME OF THE HIGH-RES MODELS SUGGEST THE
FAR NORTHERN KILX CWA MAY GET BRUSHED BY A FEW SHOWERS...PARTICULARLY
DURING THE MORNING HOURS. BOUNDARY MAY GET PUSHED A BIT FURTHER
NORTHWARD THIS AFTERNOON AS LOW PRESSURE DEVELOPING OVER THE
PLAINS BEGINS TO TRACK EASTWARD. AS A RESULT...HAVE INCLUDED LOW
CHANCE POPS FROM THE PEORIA AREA NORTHWARD...WITH DRY CONDITIONS
EXPECTED ELSEWHERE. MAIN STORY TODAY WILL BE THE BREEZY AND WARM
WEATHER. WITH PARTIAL SUNSHINE AND SOUTHERLY WINDS GUSTING TO
AROUND 25 MPH AT TIMES...AFTERNOON HIGH TEMPS WILL SOAR WELL INTO
THE 70S.
SHORT-WAVE TROUGH CURRENTLY CROSSING THE ROCKIES WILL APPROACH
FROM THE WEST TONIGHT. THIS WILL GIVE THE STALLED FRONTAL BOUNDARY
A PUSH TO THE EAST AND SOUTH...GRADUALLY SPREADING RAIN CHANCES
INTO CENTRAL ILLINOIS OVERNIGHT. 00Z 19 APR MODELS HAVE CONTINUED
TO SLOW THE EASTWARD PROGRESS OF THE SYSTEM...WITH ALL MODELS NOW
KEEPING THE FAR E/SE CWA DRY THROUGH THE NIGHT. IN ADDITION...THE
LATEST MODEL RUN HAS ALSO CONSIDERABLY REDUCED THE EXPECTED QPF.
THIS SEEMS REASONABLE BASED ON 00Z UPPER AIR ANALYSIS SHOWING
LOW-LEVEL RIDGING BLOCKING NORTHWARD MOISTURE TRANSPORT FROM THE
GULF OF MEXICO. ONLY A NARROW RIBBON OF 850MB MOISTURE WAS NOTED
FROM THE SOUTHERN PLAINS INTO THE UPPER MIDWEST...WHILE THE DEEPEST
MOISTURE REMAINS LOCKED UP WELL TO THE E/SE ACROSS FLORIDA.
SURFACE DEWPOINTS ALSO REFLECT A GENERAL LACK OF MOISTURE...WITH
UPSTREAM VALUES ACROSS TEXAS/OKLAHOMA ONLY IN THE UPPER 40S AND
LOWER 50S. DUE TO MEAGER MOISTURE RETURN...NAM FEATURES ONLY A
THIN PLUME OF INSTABILITY DEVELOPING AHEAD OF THE APPROACHING
WAVE ACROSS THE PLAINS THIS AFTERNOON...WHICH THEN QUICKLY
DIMINISHES AS IT MOVES FURTHER EASTWARD AFTER SUNSET. HAVE
THEREFORE REMOVED THUNDER MENTION FROM THE FORECAST TONIGHT AND
FRIDAY. HAVE ALSO SPED UP THE DEPARTURE OF THE PRECIP...WITH THE
NAM/GFS/ECMWF ALL INDICATING A NARROW BAND OF MAINLY POST-FRONTAL
SHOWERS WITH PERHAPS A FEW EMBEDDED THUNDERSTORMS EXITING INTO
INDIANA BY EARLY FRIDAY EVENING. HAVE CARRIED LIKELY POPS
ALONG/WEST OF I-55 TONIGHT...THEN EAST OF I-55 FRIDAY MORNING.
RAIN CHANCES WILL THEN BEGIN TO DIMINISH FROM WEST TO EAST ACROSS
THE AREA FRIDAY AFTERNOON...WITH ONLY A FEW LINGERING SHOWERS
ACROSS THE FAR SE BY FRIDAY EVENING.
MUCH COOLER AIRMASS WILL FILTER INTO THE REGION FRIDAY NIGHT INTO
SATURDAY...WITH LOW TEMPS DROPPING INTO THE UPPER 30S/LOWER 40S
FRIDAY NIGHT AND HIGHS ONLY RECOVERING INTO THE 50S ON SATURDAY.
COLDEST NIGHT OF THE FORECAST PERIOD APPEARS TO BE SATURDAY
NIGHT...WHEN LOWS WILL DIP INTO THE MIDDLE TO UPPER 30S. FROST MAY
BE POSSIBLE EARLY SUNDAY MORNING...ALTHOUGH AN UPPER WAVE DIVING
SOUTHEASTWARD OUT OF THE NORTHERN PLAINS MAY PROVIDE ENOUGH
MID/HIGH CLOUD COVER TO KEEP IT FROM BECOMING A PROBLEM. WILL KEEP
FROST MENTION OUT OF THE FORECAST FOR NOW...UNTIL SKY COVER/WIND
DETAILS BECOME A BIT CLEARER.
LONG TERM...SUNDAY THROUGH WEDNESDAY
MODELS CONTINUE TO ADVERTISE A DEEP UPPER TROUGH DEVELOPING OVER
THE EASTERN CONUS EARLY NEXT WEEK...ALTHOUGH THE SPEED OF ITS
EVENTUAL DEPARTURE STILL REMAINS IN QUESTION. 00Z ECMWF IS THE
DEEPEST AND SLOWEST WITH THIS SYSTEM...KEEPING IT IN PLACE ACROSS
NEW ENGLAND AT LEAST THROUGH WEDNESDAY. MEANWHILE...GFS IS THE
MOST PROGRESSIVE...TAKING THE UPPER LOW INTO EASTERN CANADA AS
EARLY AS TUESDAY. CANADIAN REPRESENTS A MIDDLE-OF-THE-ROAD
SOLUTION AND WAS PREFERRED FOR THIS FORECAST PACKAGE. END RESULT
WILL BE COOL/DRY WEATHER FOR SUNDAY AND MONDAY...FOLLOWED BY A
GRADUAL WARMING TREND BY THE MIDDLE OF THE WEEK. HIGH TEMPS WILL
START OUT IN THE UPPER 50S/LOWER 60S ON SUNDAY...THEN WILL CLIMB
WELL INTO THE 70S BY WEDNESDAY.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
245 PM CDT THU APR 19 2012
...UPDATED LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1219 PM CDT THU APR 19 2012
UPPER AIR ANALYSIS AT 12Z THURSDAY INDICATED AN UPPER LEVEL JET
EXTENDED FROM WASHINGTON STATE SOUTHEAST INTO NORTHEASTERN
NEVADA. NEAR THE LEFT EXIT REGION OF THIS JET A -26 TO -28C 500MB
THERMAL TROUGH WAS LOCATED OVER MONTANA. 40 TO 50 METER HEIGHT
FALLS WERE ALSO OBSERVED AT RAPID CITY SOUTH DAKOTA AND DENVER
COLORADO WHILE ACROSS ALONG THE PACIFIC NORTHWEST 50 TO 70 METER
HEIGHT RISES WERE OCCURRING. IN THE CENTRAL PLAINS AT 12Z THURSDAY
BOTH THE 850MB AND 700MB LEVELS INDICATED AN AREA OF MOISTURE WAS
LOCATED NEAR A 850-700MB BAROCLINIC ZONE THAT EXTENDED FROM
NORTHEAST COLORADO INTO CENTRAL NEBRASKA. AT 13Z A SURFACE A COLD
FRONT EXTENDED FROM JUST WEST OF HAYS SOUTH ACROSS THE DODGE CITY
AREA INTO THE PANHANDLE OF TEXAS AND OKLAHOMA.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 152 PM CDT THU APR 19 2012
12Z NAM AND GFS REMAINS FAIRLY CONSISTENT WITH PREVIOUS RUNS IN
DEVELOPING CONVECTION LATE THIS AFTERNOON OVER THE HIGHER TERRAIN
OF COLORADO AS AN UPPER LEVEL JET APPROACHES THE ROCKIES. ANOTHER
AREA OF LATE DAY CONVECTION WILL ALSO BE POSSIBLE NEAR A COLD
FRONT WHICH WAS CROSSING SOUTH CENTRAL KANSAS AS OF 18Z. AT THIS
TIME IT APPEARS BASED ON THE HRRR AND NAM THIS FRONT WILL BE EAST
OF THE PRATT AND MEDICINE LODGE AREAS BY 00Z SO ANY PRECIPITATION
THAT WILL DEVELOP ALONG THIS BOUNDARY IS GOING TO OCCUR EAST OF
THESE LOCATIONS. FURTHER WEST BEHIND THIS FRONT THERE WILL STILL BE
SOME WEAK MID LEVEL INSTABILITY BASED ON MODEL SOUNDINGS EARLY
TONIGHT AND THE NAM EVEN GENERATES SOME VERY LIGHT QPF IN THIS AREA
OF INSTABILITY. AT THIS TIME GIVEN THE DRY AIR FORECAST BELOW THE
800MB LEVEL AM THINKING ONLY CLOUDS AND POSSIBLY VIRGA BUT WILL
CONTINUE TO MONITOR THIS AND ADJUST AS NEEDED FOR THE FIRST FEW
HOURS OF THE EVENING PERIOD.
CONVECTION DEVELOPING FURTHER WEST NEAR THE LEFT EXIT REGION OF
AN UPPER LEVEL JET APPEAR TO STAY WEST OF THE COLORADO BORDER
THROUGH 00Z. THESE STORMS ARE THEN FORECAST TO SPREAD EAST INTO
WESTERN KANSAS OVERNIGHT AS A 500MB THERMAL THROUGH WHICH WAS
LOCATED IN MONTANA AT 12Z THURSDAY MOVES SOUTHEAST INTO WESTERN
KANSAS. TRACK OF THIS UPPER TROUGH SUGGESTS PRECIPITATION CHANCES
WILL CONTINUE THROUGH EARLY FRIDAY AFTERNOON...ESPECIALLY EAST OF
HIGHWAY 283. THE PREVIOUS FORECAST HAS A DECENT HANDLE ON THE
EVOLUTION OF THIS PRECIPITATION SPREADING EAST ACROSS WESTERN
KANSAS LATER TONIGHT AND EARLY FRIDAY SO WILL STAY CLOSE TO THE
PREVIOUS TREND. DID HOWEVER POSTPONE THE ONSET OF THE
PRECIPITATION ACROSS THE FAR WEST UNTIL AFTER 00Z.
AS THE PRECIPITATION ENDS FROM WEST TO EAST THE SKIES ARE
EXPECTED TO CLEAR AS SUBSIDENCE DEVELOPS BEHIND THE UPPER LEVEL
TROUGH. BASED ON THE 18Z FRIDAY AND 00Z SATURDAY 925-950M
TEMPERATURES AND CLEARING SKIES WILL CONTINUE TO FAVOR HIGHS IN
THE MID 60S ACROSS MUCH OF WESTERN KANSAS. FURTHER EAST UPPER 50S
TO LOWER 60S APPEAR MORE REASONABLE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 245 PM CDT THU APR 19 2012
"WARM AND DRY" CAN DESCRIBE MOST OF THE EXTENDED PERIOD. WE WILL
SEE MODERATING TEMPERATURES OVER THE WEEKEND AS SURFACE LEE
TROUGHING STRENGTHENS. THE MAIN HEAT STORY BEGINS TUESDAY AND
CONTINUES THROUGH THE REST OF THE EXTENDED PERIOD AS 500 HPA
GEOPOTENTIAL HEIGHTS INCREASE IN RESPONSE TO AN AMPLIFIED RIDGE
BUILDING OVER THE ROCKIES. 850 HPA TEMPERATURES START AROUND 26-28
DEG C TUESDAY AND PEAK AROUND 28-30 DEG C BY THE END OF NEXT WEEK.
THIS SUPPORTS MIX DOWN TEMPERATURES WELL INTO THE 80S DEG F AND
MOST LIKELY SOME LOCATIONS WILL SEE >90 DEG F TEMPS. OVERNIGHT LOWS
THROUGH THE EXTENDED PERIOD WILL BE MILD AS MODERATE DEWPOINTS AND
SOUTHERLY WINDS CONTINUE. WILL KEEP SILENT POPS IN AS ANY UPPER LEVEL
FORCING REMAINS TO BE UNSEEN AND WEAK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1219 PM CDT THU APR 19 2012
GUSTY NORTH WINDS WILL DECREASE AROUND 15KTS LATE THIS AFTERNOON
BASED ON THE RUC13 AND NAMS MEAN MIXED LAYER WINDS BEHIND A COLD
FRONT THAT WILL BE CROSSING INTO CENTRAL KANSAS. SOME LATE DAY
HIGH BASED CU WILL BE POSSIBLE WITH EVEN A FEW SPRINKLES POSSIBLE
EARLY THIS EVENING AT HYS...POSSIBLY AS FAR SOUTH AS DDC. THE
BETTER CHANCE FOR PRECIPITATION HOWEVER APPEARS TO DEVELOP LATER
TONIGHT AS CONVECTION ALONG THE HIGHER TERRAIN OF COLORADO MOVES
EAST INTO WESTERN KANSAS. BASED ON MOISTURE PROFILES FROM THE
SOUNDINGS AT GCK, DDC, AND HYS LOW VFR OR HIGH MVFR CAN BE
EXPECTED FROM ANY SCATTERED SHOWERS THAT DEVELOP.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 44 61 39 76 / 50 20 0 0
GCK 43 62 40 77 / 60 20 0 0
EHA 45 66 41 79 / 50 10 0 0
LBL 45 65 40 78 / 40 20 0 0
HYS 41 60 38 76 / 30 20 0 0
P28 46 62 41 75 / 30 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
156 PM CDT THU APR 19 2012
...UPDATED SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1219 PM CDT THU APR 19 2012
UPPER AIR ANALYSIS AT 12Z THURSDAY INDICATED AN UPPER LEVEL JET
EXTENDED FROM WASHINGTON STATE SOUTHEAST INTO NORTHEASTERN
NEVADA. NEAR THE LEFT EXIT REGION OF THIS JET A -26 TO -28C 500MB
THERMAL TROUGH WAS LOCATED OVER MONTANA. 40 TO 50 METER HEIGHT
FALLS WERE ALSO OBSERVED AT RAPID CITY SOUTH DAKOTA AND DENVER
COLORADO WHILE ACROSS ALONG THE PACIFIC NORTHWEST 50 TO 70 METER
HEIGHT RISES WERE OCCURRING. IN THE CENTRAL PLAINS AT 12Z THURSDAY
BOTH THE 850MB AND 700MB LEVELS INDICATED AN AREA OF MOISTURE WAS
LOCATED NEAR A 850-700MB BAROCLINIC ZONE THAT EXTENDED FROM
NORTHEAST COLORADO INTO CENTRAL NEBRASKA. AT 13Z A SURFACE A COLD
FRONT EXTENDED FROM JUST WEST OF HAYS SOUTH ACROSS THE DODGE CITY
AREA INTO THE PANHANDLE OF TEXAS AND OKLAHOMA.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 152 PM CDT THU APR 19 2012
12Z NAM AND GFS REMAINS FAIRLY CONSISTENT WITH PREVIOUS RUNS IN
DEVELOPING CONVECTION LATE THIS AFTERNOON OVER THE HIGHER TERRAIN
OF COLORADO AS AN UPPER LEVEL JET APPROACHES THE ROCKIES. ANOTHER
AREA OF LATE DAY CONVECTION WILL ALSO BE POSSIBLE NEAR A COLD
FRONT WHICH WAS CROSSING SOUTH CENTRAL KANSAS AS OF 18Z. AT THIS
TIME IT APPEARS BASED ON THE HRRR AND NAM THIS FRONT WILL BE EAST
OF THE PRATT AND MEDICINE LODGE AREAS BY 00Z SO ANY PRECIPITATION
THAT WILL DEVELOP ALONG THIS BOUNDARY IS CURRENTLY LOOKING LESS AND
LESS LIKELY. FURTHER WEST BEHIND THIS FRONT THERE WILL STILL BE
SOME WEAK MID LEVEL INSTABILITY BASED ON MODEL SOUNDINGS EARLY
TONIGHT AND THE NAM EVEN GENERATES SOME VERY LIGHT QPF IN THIS AREA OF
INSTABILITY. AT THIS TIME GIVEN THE DRY AIR FORECAST BELOW THE 800MB
LEVEL AM THINKING ONLY CLOUDS AND POSSIBLY VIRGA BUT WILL CONTINUE TO
MONITOR THIS AND ADJUST AS NEEDED FOR THE FIRST FEW HOURS OF THE
EVENING PERIOD.
CONVECTION DEVELOPING FURTHER WEST NEAR THE LEFT EXIT REGION OF
AN UPPER LEVEL JET APPEAR TO STAY WEST OF THE COLORADO BORDER
THROUGH 00Z. THESE STORMS ARE THEN FORECAST TO SPREAD EAST INTO
WESTERN KANSAS OVERNIGHT AS A 500MB THERMAL THROUGH WHICH WAS
LOCATED IN MONTANA AT 12Z THURSDAY MOVES SOUTHEAST INTO WESTERN
KANSAS. TRACK OF THIS UPPER TROUGH SUGGESTS PRECIPITATION CHANCES
WILL CONTINUE THROUGH EARLY FRIDAY AFTERNOON...ESPECIALLY EAST OF
HIGHWAY 283. THE PREVIOUS FORECAST HAS A DECENT HANDLE ON THE
EVOLUTION OF THIS PRECIPITATION SPREADING EAST ACROSS WESTERN
KANSAS LATER TONIGHT AND EARLY FRIDAY SO WILL STAY CLOSE TO THE
PREVIOUS TREND. DID HOWEVER POSTPONE THE ONSET OF THE
PRECIPITATION ACROSS THE FAR WEST UNTIL AFTER 00Z.
AS THE PRECIPITATION ENDS FROM WEST TO EAST THE SKIES ARE
EXPECTED TO CLEAR AS SUBSIDENCE DEVELOPS BEHIND THE UPPER LEVEL
TROUGH. BASED ON THE 18Z FRIDAY AND 00Z SATURDAY 925-950M
TEMPERATURES AND CLEARING SKIES WILL CONTINUE TO FAVOR HIGHS IN
THE MID 60S ACROSS MUCH OF WESTERN KANSAS. FURTHER EAST UPPER 50S
TO LOWER 60S APPEAR MORE REASONABLE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 311 AM CDT THU APR 19 2012
A COLD FRONT AND ASSOCIATED UPPER LEVEL TROUGH WILL BEGIN TO EXIT
SOUTHWESTERN KANSAS THURSDAY NIGHT, BUT THERE COULD BE A LITTLE LEFT
OVER RAIN OR RAIN SHOWERS IN OUR EASTERN CWA EARLY FRIDAY FROM UPPER
LEVEL LIFT. THE COLD FRONT WILL BE WELL SOUTHWARD INTO OKLAHOMA BY
NOON FRIDAY, AND SLIGHT POPS WILL EXIT OUR AREA AS SURFACE HIGH
PRESSURE BEGINS TO BUILD IN FROM THE NORTHWEST. THEREAFTER, A LARGE
UPPER LEVEL HIGH PRESSURE SYSTEM WILL BUILD OVER MEXICO AND SOUTHERN
ARIZONA, WITH A HIGH PRESSURE RIDGE NORTHWARD INTO THE PACIFIC
NORTHWEST. THIS WILL BRING A WARM UP TO OUR FORECAST AREA, WITH
FRIDAY STARTING OUT IN THE 60S, BUT WITH SOME 80S POSSIBLE IN OUR
SOUTHWEST ZONES BY SUNDAY. OUR EASTERN COUNTIES WILL SEE HIGHS IN
THE MID 70S SUNDAY. THAT UPPER LEVEL HIGH PRESSURE AND AN
ASSOCIATED SURFACE HIGH WILL BECOME STRONGER BY EARLY NEXT WEEK,
WITH PLENTY OF SUNSHINE AND EVEN WARMER TEMPERATURES. ALL OF
SOUTHWESTERN KANSAS WILL REACH THE MID TO UPPER 80S BY TUESDAY, WITH
OUR FAR WESTERN COUNTIES POSSIBLY APPROACHING 90F DEGREES. THE GFS
MODEL IS THE WARMEST MODEL THEN WITH 850MB PROGGED TEMPERATURES IN
THE +28-+29C RANGE, AND THE ECMWF MODEL RIGHT BEHIND WITH 850MB
TEMPS IN THE +26C-+27C RANGE. EITHER WAY, IT WILL BE WARM TO HOT
FOR THIS TIME OF YEAR. WEDNESDAY LOOKS TO BE JUST ABOUT AS WARM,
WITH PERHAPS SOME THIN CIRRUS CLOUDS FLOWING OVERHEAD. THERE IS A
SHORT WAVE SHOWING UP AND CUTTING THROUGH THE EASTERN SIDE OF THE
UPPER HIGH, CROSSING SOUTH CENTRAL KANSAS WEDNESDAY NIGHT INTO
THURSDAY. THE CREXTENDFCST_INIT PROCEDURE PLACED 20 POPS ACROSS OUR
EASTERN HALF OF THE FORECAST AREA WEDNESDAY NIGHT, AND THEN
INCREASED POPS INTO THE 30 PERCENT CHANCE CATEGORY IN OUR NORTHEAST
SECTIONS THURSDAY. CAN NOT ARGUE WITH THIS SOLUTION, AS THE ECMWF
AND GFS BOTH HAVE THIS SHORT WAVE NEAR WESTERN TO CENTRAL KANSAS
WEDNESDAY NIGHT INTO THURSDAY. THURSDAY SHOULD STILL BE RELATIVELY
WARM WITH HIGHS IN THE LOWER TO MID 80S.
MINIMUM TEMPERATURES THROUGH THE EXTENDED PERIOD WILL START OUT COOL
SATURDAY MORNING WITH THE COLD FRONT RECENTLY PASSING THROUGH. GFS
850MB TEMPS SAT MORNING RANGE FROM +7C IN OUR SOUTHEAST TO +12C IN
OUR NORTHWEST SECTIONS. MINIMUMS WILL RISE TO THE LOWER 50S BY
MONDAY MORNING AS 850MB PROGGED TEMPS RISE TO THE 17C-20C RANGE. BY
WEDNESDAY AND THURSDAY MORNINGS, LOWS SHOULD BE IN THE MID 50S IN
THE WEST AND THE UPPER 50S IN THE EAST, AS 850MB MODEL (BOTH GFS AND
ECMWF) PROGGED TEMPS SHOW FROM 20C TO 26C DEGREES ACROSS OUR CWA BY
THOSE MORNINGS.
THE ONLY BREEZY TO WINDY DAY SHOULD BE FRIDAY WITH NORTH WINDS
BEHIND THE COLD FRONT IN THE 15G30MPH RANGE. WINDS WILL GENERALLY
BE NORTH TO NORTHEAST AND LIGHT THROUGH SUNDAY NIGHT AS THE SURFACE
HIGH DOMINATES. WINDS WILL SHIFT TO THE SOUTH OR SOUTHEAST MONDAY
AND INCREASE SLIGHTLY INTO THE 15G25MPH RANGE, AND WHEN THE UPPER
LEVEL SHORT WAVE CROSSES OUR FORECAST AREA WEDNESDAY INTO THURSDAY,
EXPECT SOUTH WINDS IN THE 15 TO 20 MPH RANGE AND GUSTY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1219 PM CDT THU APR 19 2012
GUSTY NORTH WINDS WILL DECREASE AROUND 15KTS LATE THIS AFTERNOON
BASED ON THE RUC13 AND NAMS MEAN MIXED LAYER WINDS BEHIND A COLD
FRONT THAT WILL BE CROSSING INTO CENTRAL KANSAS. SOME LATE DAY
HIGH BASED CU WILL BE POSSIBLE WITH EVEN A FEW SPRINKLES POSSIBLE
EARLY THIS EVENING AT HYS...POSSIBLY AS FAR SOUTH AS DDC. THE
BETTER CHANCE FOR PRECIPITATION HOWEVER APPEARS TO DEVELOP LATER
TONIGHT AS CONVECTION ALONG THE HIGHER TERRAIN OF COLORADO MOVES
EAST INTO WESTERN KANSAS. BASED ON MOISTURE PROFILES FROM THE
SOUNDINGS AT GCK, DDC, AND HYS LOW VFR OR HIGH MVFR CAN BE
EXPECTED FROM ANY SCATTERED SHOWERS THAT DEVELOP.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 61 38 75 / 50 20 0 0
GCK 45 62 40 76 / 50 20 0 0
EHA 48 66 42 78 / 50 10 0 0
LBL 48 65 41 78 / 40 20 0 0
HYS 44 60 37 74 / 30 20 0 0
P28 46 62 39 75 / 30 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1222 PM CDT THU APR 19 2012
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1219 PM CDT THU APR 19 2012
UPPER AIR ANALYSIS AT 12Z THURSDAY INDICATED AN UPPER LEVEL JET
EXTENDED FROM WASHINGTON STATE SOUTHEAST INTO NORTHEASTERN
NEVADA. NEAR THE LEFT EXIT REGION OF THIS JET A -26 TO -28C 500MB
THERMAL TROUGH WAS LOCATED OVER MONTANA. 40 TO 50 METER HEIGHT
FALLS WERE ALSO OBSERVED AT RAPID CITY SOUTH DAKOTA AND DENVER
COLORADO WHILE ACROSS ALONG THE PACIFIC NORTHWEST 50 TO 70 METER
HEIGHT RISES WERE OCCURRING. IN THE CENTRAL PLAINS AT 12Z THURSDAY
BOTH THE 850MB AND 700MB LEVELS INDICATED AN AREA OF MOISTURE WAS
LOCATED NEAR A 850-700MB BAROCLINIC ZONE THAT EXTENDED FROM
NORTHEAST COLORADO INTO CENTRAL NEBRASKA. AT 13Z A SURFACE A COLD
FRONT EXTENDED FROM JUST WEST OF HAYS SOUTH ACROSS THE DODGE CITY
AREA INTO THE PANHANDLE OF TEXAS AND OKLAHOMA.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CDT THU APR 19 2012
THE LARGEST FORECAST CHALLENGES IN THE NEAR TERM INCLUDE FRONTAL
TIMING AND STRENGTH, TEMPERATURES THIS AFTERNOON, AS WELL AS
CONVECTIVE AND RAIN CHANCES IN THE PERIODS THIS EVENING THROUGH THE
OVERNIGHT. THE CURRENT TRENDS POINT TOWARD THE NAM AND LAMP GUIDANCE
BRINGING THE COLD FRONT THROUGH THE AREA BETWEEN 12 AN 15 UTC THIS
MORNING. THE NAM FORECAST THERMAL AND WIND PROFILES DO NOT INDICATE
A PARTICULARLY DEEP MIXING LAYER INTO THE AFTERNOON. HOWEVER, STRONG
SUPERADIABATIC LAPSE RATES SHOULD LEAD TO FREQUENT GUSTS ABOVE 30
KNOTS IN THE EARLY AFTERNOON GIVEN THE WIND PROFILES, AND WINDS COULD
APPROACH ADVISORY LEVELS IN THE WESTERN COUNTIES. INSTABILITY WILL
BE SUFFICIENT TO PRODUCE SURFACE BASED CONVECTION ALONG THE COLD
FRONT LATE THIS AFTERNOON INTO THIS EVENING, BUT THE FRONT WILL
LIKELY BE POSITIONED TOO FAR EAST OF WESTERN KANSAS TO AFFECT OUR
AREA. HOWEVER, SOME WIDELY SCATTERED SHOWERS AND THUNDERSTORMS MAY
OCCUR BEHIND THE BOUNDARY ACROSS CENTRAL KANSAS IN THE AFTERNOON
WITH LITTLE CHANCE OF BEING SEVERE. THE DEFORMATION PRODUCED BY A
STRONG LEAD JET SEGMENT OVERNIGHT AND WILL PROBABLY PRODUCE SOME
RAIN SHOWERS OVER THE HIGH PLAINS REGION LATER TONIGHT. THE ISSUE
WILL BE BETTER SOLVED IN THE NOWCAST PHASE, BUT AFTER CONSIDERING
THE MODEL SOLUTIONS, THE SREF WAS USED AS A START FOR PROBABILITIES
OVERNIGHT. INITIALLY ISOLATED CONVECTION/THUNDERSTORMS COULD
ACCOMPANY ANY PRECIPITATION THROUGH THE EVENING. INSTABILITY WILL
LIKELY THEN DECREASE AND SHOWERS WOULD BECOME THE DOMINANT
PRECIPITATION EXPECTED.
MILD TEMPERATURES WILL BE SEEN TO START OFF THIS MORNING, GENERALLY
IN THE 50S AND FALLING TOWARD 12Z. THE MODEL CONSENSUS FOR THIS
AFTERNOON AGREE OVERWHELMINGLY, BRINGING VALUES INTO THE LOW TO MID
70S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 311 AM CDT THU APR 19 2012
A COLD FRONT AND ASSOCIATED UPPER LEVEL TROUGH WILL BEGIN TO EXIT
SOUTHWESTERN KANSAS THURSDAY NIGHT, BUT THERE COULD BE A LITTLE LEFT
OVER RAIN OR RAINSHOWERS IN OUR EASTERN CWA EARLY FRIDAY FROM UPPER
LEVEL LIFT. THE COLD FRONT WILL BE WELL SOUTHWARD INTO OKLAHOMA BY
NOON FRIDAY, AND SLIGHT POPS WILL EXIT OUR AREA AS SURFACE HIGH
PRESSURE BEGINS TO BUILD IN FROM THE NORTHWEST. THEREAFTER, A LARGE
UPPER LEVEL HIGH PRESSURE SYSTEM WILL BUILD OVER MEXICO AND SOUTHERN
ARIZONA, WITH A HIGH PRESSURE RIDGE NORTHWARD INTO THE PACIFIC
NORTHWEST. THIS WILL BRING A WARM UP TO OUR FORECAST AREA, WITH
FRIDAY STARTING OUT IN THE 60S, BUT WITH SOME 80S POSSIBLE IN OUR
SOUTHWEST ZONES BY SUNDAY. OUR EASTERN COUNTIES WILL SEE HIGHS IN
THE MID 70S SUNDAY. THAT UPPER LEVEL HIGH PRESSURE AND AN
ASSOCIATED SURFACE HIGH WILL BECOME STRONGER BY EARLY NEXT WEEK,
WITH PLENTY OF SUNSHINE AND EVEN WARMER TEMPERATURES. ALL OF
SOUTHWESTERN KANSAS WILL REACH THE MID TO UPPER 80S BY TUESDAY, WITH
OUR FAR WESTERN COUNTIES POSSIBLY APPROACHING 90F DEGREES. THE GFS
MODEL IS THE WARMEST MODEL THEN WITH 850MB PROGGED TEMPERATURES IN
THE +28-+29C RANGE, AND THE ECMWF MODEL RIGHT BEHIND WITH 850MB
TEMPS IN THE +26C-+27C RANGE. EITHER WAY, IT WILL BE WARM TO HOT
FOR THIS TIME OF YEAR. WEDNESDAY LOOKS TO BE JUST ABOUT AS WARM,
WITH PERHAPS SOME THIN CIRRUS CLOUDS FLOWING OVERHEAD. THERE IS A
SHORT WAVE SHOWING UP AND CUTTING THROUGH THE EASTERN SIDE OF THE
UPPER HIGH, CROSSING SOUTH CENTRAL KANSAS WEDNESDAY NIGHT INTO
THURSDAY. THE CREXTENDFCST_INIT PROCEDURE PLACED 20 POPS ACROSS OUR
EASTERN HALF OF THE FORECAST AREA WEDNESDAY NIGHT, AND THEN
INCREASED POPS INTO THE 30 PERCENT CHANCE CATEGORY IN OUR NORTHEAST
SECTIONS THURSDAY. CAN NOT ARGUE WITH THIS SOLUTION, AS THE ECMWF
AND GFS BOTH HAVE THIS SHORT WAVE NEAR WESTERN TO CENTRAL KANSAS
WEDNESDAY NIGHT INTO THURSDAY. THURSDAY SHOULD STILL BE RELATIVELY
WARM WITH HIGHS IN THE LOWER TO MID 80S.
MINIMUM TEMPERATURES THROUGH THE EXTENDED PERIOD WILL START OUT COOL
SATURDAY MORNING WITH THE COLD FRONT RECENTLY PASSING THROUGH. GFS
850MB TEMPS SAT MORNING RANGE FROM +7C IN OUR SOUTHEAST TO +12C IN
OUR NORTHWEST SECTIONS. MINIMUMS WILL RISE TO THE LOWER 50S BY
MONDAY MORNING AS 850MB PROGGED TEMPS RISE TO THE 17C-20C RANGE. BY
WEDNESDAY AND THURSDAY MORNINGS, LOWS SHOULD BE IN THE MID 50S IN
THE WEST AND THE UPPER 50S IN THE EAST, AS 850MB MODEL (BOTH GFS AND
ECMWF) PROGGED TEMPS SHOW FROM 20C TO 26C DEGREES ACROSS OUR CWA BY
THOSE MORNINGS.
THE ONLY BREEZY TO WINDY DAY SHOULD BE FRIDAY WITH NORTH WINDS
BEHIND THE COLD FRONT IN THE 15G30MPH RANGE. WINDS WILL GENERALLY
BE NORTH TO NORTHEAST AND LIGHT THROUGH SUNDAY NIGHT AS THE SURFACE
HIGH DOMINATES. WINDS WILL SHIFT TO THE SOUTH OR SOUTHEAST MONDAY
AND INCREASE SLIGHTLY INTO THE 15G25MPH RANGE, AND WHEN THE UPPER
LEVEL SHORT WAVE CROSSES OUR FORECAST AREA WEDNESDAY INTO THURSDAY,
EXPECT SOUTH WINDS IN THE 15 TO 20 MPH RANGE AND GUSTY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1219 PM CDT THU APR 19 2012
GUSTY NORTH WINDS WILL DECREASE AROUND 15KTS LATE THIS AFTERNOON
BASED ON THE RUC13 AND NAMS MEAN MIXED LAYER WINDS BEHIND A COLD
FRONT THAT WILL BE CROSSING INTO CENTRAL KANSAS. SOME LATE DAY
HIGH BASED CU WILL BE POSSIBLE WITH EVEN A FEW SPRINKLES POSSIBLE
EARLY THIS EVENING AT HYS...POSSIBLY AS FAR SOUTH AS DDC. THE
BETTER CHANCE FOR PRECIPITATION HOWEVER APPEARS TO DEVELOP LATER
TONIGHT AS CONVECTION ALONG THE HIGHER TERRAIN OF COLORADO MOVES
EAST INTO WESTERN KANSAS. BASED ON MOISTURE PROFILES FROM THE
SOUNDINGS AT GCK, DDC, AND HYS LOW VFR OR HIGH MVFR CAN BE
EXPECTED FROM ANY SCATTERED SHOWERS THAT DEVELOP.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 74 45 63 38 / 10 50 20 0
GCK 73 45 65 40 / 10 70 10 0
EHA 72 48 65 42 / 10 50 0 0
LBL 74 48 66 41 / 10 70 10 0
HYS 71 44 62 37 / 20 30 20 0
P28 77 46 64 39 / 30 30 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BURGERT
SYNOPSIS...BURGERT
SHORT TERM...RUSSELL
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
849 AM CDT THU APR 19 2012
...UPDATED FOR TIMING OF FRONTAL PASSAGE AND WINDS BEHIND THE FRONT...
.SYNOPSIS...
ISSUED AT 338 AM CDT THU APR 19 2012
BROAD ZONAL FLOW WAS IN PLACE ACROSS THE WESTERN 2/3RDS OF THE CONUS
OVERNIGHT IN THE UPPER LEVELS, AND A STRONGER 150 KT JET SEGMENT WAS
IMPINGING ON NORTHERN CALIFORNIA. A TROUGH WAS EVIDENT IN THE
OBJECTIVE ANALYSIS AT THE 700 MB LEVEL OVER THE ROCKIES. WARM 850
MB LEVEL TEMPERATURES OF 15-18 DEGREES C WERE IN PLACE ACROSS THE
CENTRAL AND SOUTHERN HIGH PLAINS REGIONS, WHILE THE HEIGHT FIELD
INDICATED A WEAK CYCLONIC FLOW ACROSS THE CENTRAL ROCKIES AND THE
LEE PLAINS. REASONABLY MILD TEMPERATURES HAVE BEEN IN PLACE
OVERNIGHT AS THE COMBINATION OF WESTERN KANSAS GENERALLY BEING IN A
WARM SECTOR AIRMASS AND OVERSPREADING THICKENING CIRROSTRATUS HAS
INFLUENCED TEMPERATURES TO THE WARM SIDE OVERNIGHT. THE METAR
OBJECTIVE ANALYSIS SHOWS SURFACE PRESSURE FALL INCREASING OVER
SOUTHWEST KANSAS AND SURFACE WINDS ARE INCREASING OVER NORTHEAST
COLORADO AS A RESULT.
&&
.UPDATE...
ISSUED AT 845 AM CDT THU APR 19 2012
AS OF 13Z A SURFACE COLD FRONT WAS ALREADY CROSSING DDC AND HYS.
BEHIND THIS FRONT GUSTY NORTHWEST WINDS HAD DEVELOPED. BASED ON
THE MEAN MIXED LAYER WINDS BEHIND THIS FRONT THE PREVIOUS SHIFT
APPEARS TO HAVE HAD THE RIGHT IDEA THAT THERE WILL BE A WINDOW OF WIND
SPEEDS OF 25 TO NEAR 30 MPH FOR A FEW HOURS LATER THIS MORNING.
THE HRRR CURRENTLY APPEARS TO HAVE A BETTER HANDLE ON THE SPEED
OF THIS FRONT SO DID TREND TOWARDS THE FASTER HRRR SOLUTION. ALSO ADJUSTED
THE TIME FRAME OF STRONGER WINDS BEHIND THIS FRONT ACCORDINGLY. IN
ADDITION SOME MVFR CIGS ALSO OBSERVED AND BASED ON SATELLITE
TRENDS AND RUC13 IT APPEAR THESE CLOUDS WILL ERODE THROUGH THE THE
LATE MORNING AND IMPACT ONLY GCK AND HYS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CDT THU APR 19 2012
THE LARGEST FORECAST CHALLENGES IN THE NEAR TERM INCLUDE FRONTAL
TIMING AND STRENGTH, TEMPERATURES THIS AFTERNOON, AS WELL AS
CONVECTIVE AND RAIN CHANCES IN THE PERIODS THIS EVENING THROUGH THE
OVERNIGHT. THE CURRENT TRENDS POINT TOWARD THE NAM AND LAMP GUIDANCE
BRINGING THE COLD FRONT THROUGH THE AREA BETWEEN 12 AN 15 UTC THIS
MORNING. THE NAM FORECAST THERMAL AND WIND PROFILES DO NOT INDICATE
A PARTICULARLY DEEP MIXING LAYER INTO THE AFTERNOON. HOWEVER, STRONG
SUPERADIABATIC LAPSE RATES SHOULD LEAD TO FREQUENT GUSTS ABOVE 30
KNOTS IN THE EARLY AFTERNOON GIVEN THE WIND PROFILES, AND WINDS COULD
APPROACH ADVISORY LEVELS IN THE WESTERN COUNTIES. INSTABILITY WILL
BE SUFFICIENT TO PRODUCE SURFACE BASED CONVECTION ALONG THE COLD
FRONT LATE THIS AFTERNOON INTO THIS EVENING, BUT THE FRONT WILL
LIKELY BE POSITIONED TOO FAR EAST OF WESTERN KANSAS TO AFFECT OUR
AREA. HOWEVER, SOME WIDELY SCATTERED SHOWERS AND THUNDERSTORMS MAY
OCCUR BEHIND THE BOUNDARY ACROSS CENTRAL KANSAS IN THE AFTERNOON
WITH LITTLE CHANCE OF BEING SEVERE. THE DEFORMATION PRODUCED BY A
STRONG LEAD JET SEGMENT OVERNIGHT AND WILL PROBABLY PRODUCE SOME
RAIN SHOWERS OVER THE HIGH PLAINS REGION LATER TONIGHT. THE ISSUE
WILL BE BETTER SOLVED IN THE NOWCAST PHASE, BUT AFTER CONSIDERING
THE MODEL SOLUTIONS, THE SREF WAS USED AS A START FOR PROBABILITIES
OVERNIGHT. INITIALLY ISOLATED CONVECTION/THUNDERSTORMS COULD
ACCOMPANY ANY PRECIPITATION THROUGH THE EVENING. INSTABILITY WILL
LIKELY THEN DECREASE AND SHOWERS WOULD BECOME THE DOMINANT
PRECIPITATION EXPECTED.
MILD TEMPERATURES WILL BE SEEN TO START OFF THIS MORNING, GENERALLY
IN THE 50S AND FALLING TOWARD 12Z. THE MODEL CONSENSUS FOR THIS
AFTERNOON AGREE OVERWHELMINGLY, BRINGING VALUES INTO THE LOW TO MID
70S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 311 AM CDT THU APR 19 2012
A COLD FRONT AND ASSOCIATED UPPER LEVEL TROUGH WILL BEGIN TO EXIT
SOUTHWESTERN KANSAS THURSDAY NIGHT, BUT THERE COULD BE A LITTLE LEFT
OVER RAIN OR RAINSHOWERS IN OUR EASTERN CWA EARLY FRIDAY FROM UPPER
LEVEL LIFT. THE COLD FRONT WILL BE WELL SOUTHWARD INTO OKLAHOMA BY
NOON FRIDAY, AND SLIGHT POPS WILL EXIT OUR AREA AS SURFACE HIGH
PRESSURE BEGINS TO BUILD IN FROM THE NORTHWEST. THEREAFTER, A LARGE
UPPER LEVEL HIGH PRESSURE SYSTEM WILL BUILD OVER MEXICO AND SOUTHERN
ARIZONA, WITH A HIGH PRESSURE RIDGE NORTHWARD INTO THE PACIFIC
NORTHWEST. THIS WILL BRING A WARM UP TO OUR FORECAST AREA, WITH
FRIDAY STARTING OUT IN THE 60S, BUT WITH SOME 80S POSSIBLE IN OUR
SOUTHWEST ZONES BY SUNDAY. OUR EASTERN COUNTIES WILL SEE HIGHS IN
THE MID 70S SUNDAY. THAT UPPER LEVEL HIGH PRESSURE AND AN
ASSOCIATED SURFACE HIGH WILL BECOME STRONGER BY EARLY NEXT WEEK,
WITH PLENTY OF SUNSHINE AND EVEN WARMER TEMPERATURES. ALL OF
SOUTHWESTERN KANSAS WILL REACH THE MID TO UPPER 80S BY TUESDAY, WITH
OUR FAR WESTERN COUNTIES POSSIBLY APPROACHING 90F DEGREES. THE GFS
MODEL IS THE WARMEST MODEL THEN WITH 850MB PROGGED TEMPERATURES IN
THE +28-+29C RANGE, AND THE ECMWF MODEL RIGHT BEHIND WITH 850MB
TEMPS IN THE +26C-+27C RANGE. EITHER WAY, IT WILL BE WARM TO HOT
FOR THIS TIME OF YEAR. WEDNESDAY LOOKS TO BE JUST ABOUT AS WARM,
WITH PERHAPS SOME THIN CIRRUS CLOUDS FLOWING OVERHEAD. THERE IS A
SHORT WAVE SHOWING UP AND CUTTING THROUGH THE EASTERN SIDE OF THE
UPPER HIGH, CROSSING SOUTH CENTRAL KANSAS WEDNESDAY NIGHT INTO
THURSDAY. THE CREXTENDFCST_INIT PROCEDURE PLACED 20 POPS ACROSS OUR
EASTERN HALF OF THE FORECAST AREA WEDNESDAY NIGHT, AND THEN
INCREASED POPS INTO THE 30 PERCENT CHANCE CATEGORY IN OUR NORTHEAST
SECTIONS THURSDAY. CAN NOT ARGUE WITH THIS SOLUTION, AS THE ECMWF
AND GFS BOTH HAVE THIS SHORT WAVE NEAR WESTERN TO CENTRAL KANSAS
WEDNESDAY NIGHT INTO THURSDAY. THURSDAY SHOULD STILL BE RELATIVELY
WARM WITH HIGHS IN THE LOWER TO MID 80S.
MINIMUM TEMPERATURES THROUGH THE EXTENDED PERIOD WILL START OUT COOL
SATURDAY MORNING WITH THE COLD FRONT RECENTLY PASSING THROUGH. GFS
850MB TEMPS SAT MORNING RANGE FROM +7C IN OUR SOUTHEAST TO +12C IN
OUR NORTHWEST SECTIONS. MINIMUMS WILL RISE TO THE LOWER 50S BY
MONDAY MORNING AS 850MB PROGGED TEMPS RISE TO THE 17C-20C RANGE. BY
WEDNESDAY AND THURSDAY MORNINGS, LOWS SHOULD BE IN THE MID 50S IN
THE WEST AND THE UPPER 50S IN THE EAST, AS 850MB MODEL (BOTH GFS AND
ECMWF) PROGGED TEMPS SHOW FROM 20C TO 26C DEGREES ACROSS OUR CWA BY
THOSE MORNINGS.
THE ONLY BREEZY TO WINDY DAY SHOULD BE FRIDAY WITH NORTH WINDS
BEHIND THE COLD FRONT IN THE 15G30MPH RANGE. WINDS WILL GENERALLY
BE NORTH TO NORTHEAST AND LIGHT THROUGH SUNDAY NIGHT AS THE SURFACE
HIGH DOMINATES. WINDS WILL SHIFT TO THE SOUTH OR SOUTHEAST MONDAY
AND INCREASE SLIGHTLY INTO THE 15G25MPH RANGE, AND WHEN THE UPPER
LEVEL SHORT WAVE CROSSES OUR FORECAST AREA WEDNESDAY INTO THURSDAY,
EXPECT SOUTH WINDS IN THE 15 TO 20 MPH RANGE AND GUSTY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 620 AM CDT THU APR 19 2012
A WEAK WARM FRONT IS POSITIONED FROM WEST CENTRAL INTO NORTHERN
KANSAS THIS EARLY THIS MORNING. PLENTY OF MOISTURE ALOFT WILL
RESULT IN BKN TO OVC CIRRUS CLOUDS IN THE 20,000 FT LEVEL. A COLD
FRONT WILL PASS THROUGH EARLY TODAY AND OVERTAKE THE WARM FRONT,
CAUSING SOUTH WINDS TO SHIFT NORTH AND INCREASE INTO THE 13G25KT
RANGE. AS THE SURFACE HEATS AND AN UPPER LEVEL DISTURBANCE CROSSES
TONIGHT, A FEW THUNDERSTORMS ARE POSSIBLE AFTER MIDNIGHT IN THE
KGCK AREA, AND EVEN LATER IN THE KDDC AND KHYS TAF SITES. IF ANY
TAF SITE EXPERIENCES CONVECTION, CIGS AND VSBYS COULD POSSIBLY
LOWER TO MVFR CONDITIONS TEMPORARILY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 74 45 63 38 / 10 50 20 0
GCK 73 45 65 40 / 10 70 10 0
EHA 72 48 65 42 / 10 50 0 0
LBL 74 48 66 41 / 10 70 10 0
HYS 71 44 62 37 / 20 30 20 0
P28 77 46 64 39 / 30 30 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BURGERT
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...BURKE
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1225 AM EDT THU APR 19 2012
.SYNOPSIS...
LOW PRESSURE MOVES OFF THE THE NORTH CAROLINA COAST THIS MORNING.
HIGH PRESSURE RETURNS THIS AFTERNOON THROUGH FRIDAY NIGHT. A COLD
FRONT CROSSES THE AREAS SATURDAY. A COMPLEX STORM SYSTEM WILL IMPACT
THE REGION SUNDAY THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATED GRIDS TO REFLECT CURRENT RADAR TRENDS...ESPECIALLY ACROSS
NC COUNTIES WHERE THE SOLID SHIELD OF RAIN HAS PROMPTED AN UPGRADE
TO CATEGORICAL POPS FOR NEXT FEW HOURS. AXIS OF RAIN EXPECTED TO
SHIFT TOWARD THE COAST AFTER 06Z WITH PCPN BECOMING MORE SPOTTY OR
EVEN END ACROSS WESTERN COUNTIES (PER LATEST RUC13 / NAM TRENDS).
ONLY A FEW HUNDREDTHS QPF EXPECTED MOST AREAS EXCEPT SERN AREAS
WHERE UP TO ONE QUARTER INCH PSBL. LOWS U40S-M50S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
THE SHORTWAVE TROUGH PUSHES OFF THE COAST BETWEEN 12Z-15Z THURSDAY
WITH RAIN LINGERING ACROSS MAINLY EASTERN AREAS IN THE MORNING.
DRY WX RETURNS TO ALL AREAS BY AFTERNOON...EXCEPT PERHAPS A
LINGERING ISOLATED SHOWER OVER SERN COASTAL AREAS...AS HIGH
PRESSURE RETURNS. WILL SEE SOME SUNSHINE RETURNING BY AFTERNOON...
ESPECIALLY WESTERN AREAS. ONSHORE FLOW WILL LIMIT MAX TEMP
RECOVERY. HIGHS WILL RANGE FROM THE LOW 60S AT THE COAST TO AROUND
70 IN THE PIEDMONT.
EXPECTING MAINLY DRY CONDITIONS THURS NIGHT THROUGH FRIDAY NIGHT
WITH HIGH PRESSURE SITUATED OFF THE COAST. HOWEVER...MODELS ARE
HINTING AT A COASTAL FRONT DEVELOPING ALONG THE SERN U.S. COAST
WHICH MAY CAUSE ISOLATED SHOWERS/TSTMS OVER SERN COASTAL AREAS
FRIDAY...PERHAPS PUSHING FARTHER NORTH FRIDAY NIGHT AS SOUTHERLY
FLOW INCREASES AHEAD OF THE NEXT STORM SYSTEM. HAVE INSERTED SOME
SLIGHT CHC POPS DURING THIS TIME. LOWS THURSDAY NIGHT IN THE
UPR 40S NW TO THE MID 50 SERN COASTAL AREAS. FRIDAY`S HIGHS WILL
RECOVER INTO THE 70S. LOWS FRIDAY NIGHT WILL BE IN THE 50S.
A MORE COMPLEX STORM SYSTEM IS EXPECTED TO BEGIN IMPACTING THE
REGION ON SATURDAY. HOWEVER...THERE IS STILL A FAIR AMOUNT OF
UNCERTAINTY IN THE MODELS REGARDING TIMING OF THIS NEXT SYSTEM SO
WILL NOT TRY TO GET TO DETAILED WITH FORECAST JUST YET. FOR
NOW...HAVE GONE WITH CHANCE POPS ACROSS THE REGION THROUGHOUT THE
DAY...BUT BEST RAIN/TSTM CHANCES WILL PROBABLY BE IN THE
AFTERNOON. DEEP SW FLOW IN ADVANCE OF THIS SYSTEM WILL ALLOW FOR A
NICE WARM UP ON SATURDAY WITH HIGHS WELL INTO THE 70S AND LOW 80S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A SIGNIFICANT RAIN EVENT IS SET FOR THE WEEKEND. AN UPPER LEVEL
TROUGH DEEPENS OVER THE EASTERN PART OF THE NATION AND DRAWS A LOW
PRESSURE SYSTEM FROM THE GULF OF MEXICO. PLENTY OF MOISTURE WILL
ACCOMPANY THE LOW WITH OVER AN INCH OF PRECIPITABLE WATER. HPC
INDICATES 1 TO 3 INCHES OF RAINFALL ACROSS THE AREA THROUGH 12Z
MONDAY WITH THE HEAVIEST RAIN OVER THE PIEDMONT. CHANCES FOR
SHOWERS BEGIN SATURDAY AND CONTINUE THROUGH MONDAY WITH LIKELY
POPS FOR SUNDAY AND SUNDAY NIGHT. THERE WILL BE A CHANCE FOR TSTMS
ACROSS SRN PORTIONS SRN VA/NC SATURDAY NIGHT AND SUNDAY.
THE SURFACE LOW MOVES NORTHEAST THROUGH OR JUST EAST OF OUR AREA
SUNDAY NIGHT/EARLY MONDAY. THIS SYSTEM MOVES OFF TO THE NORTHEAST
BY TUESDAY. A LOW PRESSURE SYSTEM NORTH OF THE GREAT LAKES AND
HIGH PRESSURE OVER THE GULF OF MEXICO WILL RESULT IN W/SW WINDS
TO THE AREA WEDNESDAY.
WARM TEMPERATURES SATURDAY WILL BE REPLACED BY COOLER READINGS
SUNDAY THROUGH TUESDAY WHEN HIGHS ARE FORECAST TO BE MAINLY IN THE
60S. HIGHS WARM TO THE LOWER 70S ON WEDNESDAY. LOWS IN THE MID TO
UPPER 50S SUNDAY MORNING COOL TO THE 40S TUESDAY AND WEDNESDAY
MORNINGS.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
AS OF 23Z...RAIN/LOWER CLOUDS STILL MAINLY N AND W OF THE TAF
SITES...ALTHOUGH BEGINNING TO ADVANCE EASTWARD FROM LYH TO FVX.
HAVE TIMED TAFS TO BRING CIGS DOWN TO < 1 K FT AT ALL SITES EXCEPT
KSBY SOMETIME AFTER 06Z (AND INCLUDED A TEMPO GROUP FOR KRIC FROM
05Z-08Z). LOWEST CIGS GENLY EXPECTED BETWEEN 08-14Z WITH SLOWLY
IMPROVING CONDITIONS THEREAFTER...AND MAINLY VFR CONDITIONS FOR
THE AFTN (MVFR CIGS MAY LINGER NEAR THE COAST AT KORF/KECG THROUGH
18-20Z OR SO).
MAINLY VFR CONDITIONS CONTINUE THURSDAY NIGHT THROUGH MIDDAY SATURDAY.
ALTHOUGH SOME MVFR/IFR PSBL IN THE EARLY MRNG HOURS/06-12Z. SCATTERED
SHOWERS/TSTMS SAT AFTN/EVENG THEN A WIDESPREAD PCPN EVENT IS
EXPECTED TO BEGIN SAT NIGHT AND LAST INTO MONDAY. LOOK FOR PERIODS
OF MVFR/IFR.
&&
.MARINE...
THE MARINE PICTURE WILL BE UNSETTLED FOR THE NEXT SEVERAL DAYS.
HAVE MADE SOME ADJUSTMENTS TO HEADLINES...DECIDED TO EXTEND SCA ON
THE COAST ONE ZONE FARTHER NORTH (TO INCLUDE ALL ZONES S OF
PARRAMORE ISLAND) AND THROUGH THU EVENING AS SWELLS SHOULD KEEP SEAS AT
LEAST 5 FT THROUGH THIS TIMEFRAME. ALSO EXTENDED SCA FOR MOUTH OF
THE BAY THROUGH LATE THU MORNING AS EASTERLY FLOW KEEPS WAVES 3-4
FT. OTHERWISE A WEAK SURGE IS LIKELY EARLY THU MORNING BUT HAVE
WINDS AND WAVES/SEAS CAPPED JUST BELOW CRITERIA.
ALTHOUGH DETAILS AND TIMING REMAIN UNCERTAIN A MORE SIGNIFICANT SCA
EVENT IS LIKELY FROM SUNDAY INTO EARLY NEXT WEEK AS HIGH PRESSURE
WILL BE CENTERED OVER ERN CANADA WITH STRONG LOW PRESSURE PUSHING
OFF THE SE COAST AND SLOWLY MOVING NE ALONG THE GULF STREAM.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ654-656-
658.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ634.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...JDM
LONG TERM...LSA
AVIATION...LKB
MARINE...LKB/LSA
AREA FORECAST DISCUSSION...UPDATED
NWS GAYLORD MI
700 PM EDT THU APR 19 2012
.SYNOPSIS...
ISSUED AT 433 PM EDT THU APR 19 2012
A STORM SYSTEM ORGANIZING OVER THE PLAINS...WILL LIFT TOWARD THE
OHIO VALLEY TONIGHT...BEFORE EXITING EAST INTO LAKE ONTARIO FRIDAY.
RAIN WILL OVERSPREAD THE STATE THIS EVENING...IN ADVANCE OF THE
APPROACHING SYSTEM. THE RAIN WILL CHANGE TO SNOW ACROSS EAST UPPER
AND THE STRAITS REGION OVERNIGHT...AS COLDER AIR FILTERS INTO THE
NORTHERN GREAT LAKES. COLD AIR WILL CONTINUE TO PUSH ACROSS THE STATE
FRIDAY...GENERATING SNOW FOR MUCH OF NORTHERN MICHIGAN.
HIGH PRESSURE FROM THE UPPER MIDWEST AND CENTRAL CANADA...WILL BUILD
INTO THE GREAT LAKES FRIDAY NIGHT...ON THE BACKSIDE OF THE EXITING
OHIO VALLEY SYSTEM. HIGH PRESSURE WILL THEN LINGER OVER THE STATE
INTO THE BEGINNING OF THE UPCOMING WORK WEEK. THIS PATTERN WILL
GENERATE SOME SUN AND MILD TEMPERATURES THROUGH THE WEEKEND.
&&
.UPDATE...
ISSUED AT 652 PM EDT THU APR 19 2012
PRIMARY UPDATE AT THIS TIME IS TO REFINE LEADING EDGE OF PRECIP
FIELD THAT IS NOW ADVANCING NORTHEAST INTO THE CWA. SURFACE LOW
NOW OVER SOUTHEASTERN IOWA WITH IMPRESSIVE WARM ADVECTION PLUME AS
BAND OF ONE INCH PWATS SURGE NORTH OVER TIGHTENING FRONTAL BOUNDARY.
OTHER FIELDS NEED VERY LITTLE IN THE WAY OF UPDATING.
DUAL POL PRODUCTS SUGGESTING A MELTING LEVEL AROUND 4KFT AGL
ATTM...SOMEWHAT BELOW NEAR TERM GUIDANCE. STILL SAFELY STARING AS
RAIN...BUT WILL BE WATCHING THESE TRENDS /AND UPCOMING 00Z APX
RAOB/ FOR MORE CLUES TO THE LLEVEL THERMAL FIELDS AS LLEVEL
AGEOSTROPHIC NORTHERLIES SLOWLY COOL THE BOUNDARY LAYER.
AM A LITTLE CONCERNED GIVEN PLACEMENT OF RUC H85-H7 FGEN SIGNATURE
/WHICH RIGHT NOW IS LINING UP BETTER WITH PRECIP PLACEMENT THAN FN
CONVERGENCE/ ALONG WITH RECENT HRRR TRENDS THAT SUGGEST THAT THE
SOUTHERN EDGE OF THE PRECIPITATION SHIELD MAY ADVANCE A BIT
FURTHER NORTH THAN CURRENTLY INDICATED...ESPECIALLY AFTER
MIDNIGHT. WILL NOT MAKE CHANGES TO THIS PORTION OF THE FORECAST
JUST YET...BUT THIS WOULD MEAN SOME REDUCED RAINFALL TOTALS SE OF
A CAD-APN LINE IF THE TRENDS HOLD.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 433 PM EDT
THU APR 19 2012
EARLY AFTERNOON SURFACE ANALYSIS SHOWS 1005MB SURFACE WAVE OVER
NORTHEAST KANSAS...WARM/STATIONARY FRONT EXTENDS EAST ACROSS THE
SOUTHERN HALF OF IOWA/FAR NORTHERN ILLINOIS AND UP INTO SOUTHERN
LOWER MICHIGAN. LOW LEVEL ANTICYCLONIC FLOW ACROSS NORTHERN
MICHIGAN KEEPING WINDS OUT OF THE NORTH AND KEEPING TEMPERATURES
COOLER...PERSISTENT DIURNALLY ENHANCED STRATOCUMULUS DECK ACROSS
EASTERN UPPER ALSO HELPING KEEP TEMPERATURES IN THE LOWER-MID 40S.
BAROCLINIC ZONE COMBINED WITH WELL DEFINED VORTICITY CENTER HEADED
TOWARD THE NEBRASKA/IOWA BORDER IS SPREADING RAIN SHOWERS
EAST-NORTHEAST ACROSS IOWA/SOUTHERN MINNESOTA/SOUTHERN WISCONSIN...
WITH AN AXIS OF 1+ INCH PRECIPITABLE WATER VALUES POOLED ALONG THE
FRONT.
KANSAS SURFACE LOW FORECAST TO TRACK EAST-NORTHEAST AND INTO FAR
SOUTHWEST LOWER MICHIGAN BY FRIDAY MORNING...WITH ASSOCIATED
EAST-WEST BAROCLINIC ZONE ALSO NUDGING NORTHWARD WITH A TIGHT
THERMAL GRADIENT SETTING UP ACROSS LOWER MICHIGAN. LOOKING LIKE A
GOOD SETUP FOR A MODERATE-HEAVY PRECIPITATION EVENT...AS WARM
ADVECTION NORTH OF FRONTAL ZONE COMBINES WITH STRONGLY SLOPED
FRONTOGENETIC RESPONSE AND RIGHT ENTRANCE REGION DYNAMICS FROM
DEVELOPING JET STREAK TO THE NORTH AND NORTHEAST OF LAKE SUPERIOR.
CURRENT EXPECTATION IS THAT HEAVIEST QPF WILL SET UP ACROSS FAR
NORTHWEST LOWER MICHIGAN AND THE STRAITS REGION BASED ON LOCATION OF
STRONGEST FORCING...WILL LIKELY BE A TIGHT GRADIENT TO THE NORTH
GIVEN MID LEVEL DEFORMATION AND LOWER LAYER SUBSIDENCE IN DESCENDING
BRANCH OF FRONTOGENETIC CIRCULATION. PRECIPITATION AMOUNTS IN
EXCESS OF AN INCH APPEAR POSSIBLE WITHIN A MBL-TVC-PLN AXIS (WILL
CARRY A HEAVY RAIN MENTION IN THESE AREAS). RAINFALL IS MAKING
STEADY PROGRESS ACROSS WISCONSIN...AND WILL SPREAD INTO THE FORECAST
AREA FROM THE SOUTHWEST THIS EVENING. MAIN PROBLEM IS GOING TO BE
PRECIPITATION TYPE...AS "COLDEST" AIR BUMPS UP AGAINST NORTHERN QPF
GRADIENT ACROSS EASTERN UPPER. TEMPERATURES IN THE MID 40S/DEW
POINTS IN THE MID 30S WILL ENSURE PRECIPITATION STARTS AS RAIN FROM
THE STRAITS NORTHWARD...AFTER MIDNIGHT SOME LOW LEVEL COLD ADVECTION
FROM THE NORTHEAST AND COOLING DUE TO MELTING/EVAPORATION FORECAST
TO GRADUALLY ERODE AWAY SURFACE BASED WARM LAYER. NOT EXPECTING
SURFACE TEMPERATURES TO FALL BELOW FREEZING...BUT WARM LAYER MAY
SHRINK ENOUGH TO ALLOW PRECIP TO TRANSITION TOWARD SNOW ACROSS
EASTERN UPPER AND POSSIBLY INTO THE TIP OF THE MITT COUNTIES AS
WELL. SNOW AMOUNTS OVERNIGHT WILL ALL DEPEND ON HOW QUICKLY THIS
PROCESS OCCURS (IF IT OCCURS AT ALL...WHICH IS ALSO A POSSIBILITY).
ASSUMING A LATER TRANSITION WENT WITH UP TO 2 INCHES NORTH OF THE
BRIDGE BY DAYBREAK.
SURFACE WAVE FORECAST TO HEAD EAST FROM SOUTHERN LOWER MICHIGAN AND
INTO THE LOWER GREAT LAKES DURING THE DAY FRIDAY. UPWARD FORCING
WILL STILL BE PRETTY STRONG ACROSS NORTHERN LOWER MICHIGAN TO START
THE DAY...SHIFTING EAST DURING THE MORNING WHICH WILL PULL HEAVIER
PRECIPITATION EASTWARD WITH IT. THERMAL FIELDS ACROSS EASTERN UPPER
AND FAR NORTHERN LOWER WILL STILL BE MARGINAL WITH REGARD TO PRECIP
TYPE...ESPECIALLY ALONG M-32 CORRIDOR WHERE GUIDANCE OFFERING UP
DIFFERING IDEAS. WILL PLAY WITH THE IDEA OF ALL SNOW ACROSS EASTERN
UPPER AND ALONG THE M-68 CORRIDOR...WITH A WINTRY MIX OF RAIN/
SLEET/SNOW POSSIBLE ALONG THE M-32 CORRIDOR. SEVERAL INCHES OF SNOW
POSSIBLE ACROSS THE TIP OF THE MITT AND FAR SOUTHEAST UPPER
MICHIGAN...CURRENT FORECAST WILL HAVE A BAND OF 3-5 INCHES OF SNOW
ALONG/NORTH OF M-68...HIGHLY SUBJECT TO CHANGE AND WILL BE DEPENDENT
ON HOW THERMAL PROFILE EVOLVES. SINCE IT APPEARS THAT EASTERN UPPER
MICHIGAN WILL BE MOST LIKELY TO SEE MORE PERSISTENT SNOWFALL OUT OF
THIS EVENT...WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR
CHIPPEWA/MACKINAC COUNTIES FOR LATE TONIGHT INTO FRIDAY MORNING. IF
COLDER AIR ARRIVES EARLY ENOUGH...HEADLINES WILL NEED TO BE EXPANDED
SOUTH INTO AT LEAST THE TIP OF THE MITT COUNTIES. BUT NOT CONFIDENT
ENOUGH ON TIMING YET...AND HAVE SOME TIME TO HOLD OFF SINCE GREATEST
THREAT FOR SNOWFALL ACROSS FAR NORTHERN LOWER WILL BE FRIDAY
MORNING.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 433 PM EDT
THU APR 19 2012
CURRENT QUASI-ZONAL FLOW PATTERN OVER THE LOWER 48 ABOUT SET TO GO
THROUGH DEEP AMPLIFICATION...COURTESY OF RAPID UPPER JET
INTENSIFICATION TODAY OVER ONTARIO...WITH SECONDARY STRONG UPPER JET
STREAK CUTTING INTO THE PACIFIC NORTHWEST. COMBO OF THESE WILL CARVE
OUT A DEEP EASTERN TROUGH THIS WEEKEND INTO EARLY NEXT WEEK...ITSELF
BOOKENDED BY AMPLIFYING INTERMOUNTAIN WEST AND DAVIS STRAITS
RIDGING. SAID CONFIGURATION PLACES NORTHERN MICHIGAN IN SOMEWHAT
PROLONGED PERIOD OF MAINLY DRY AND SEASONABLY COOL NORTH TO EAST
FLOW THOUGH EARLY NEXT WEEK. FORECAST CONCERNS CENTER ON TEMPERATURE
TRENDS AND PERIODIC LOW END RAIN CHANCES AS WEAK MOISTURE STARVED
WAVES ADVANCE THROUGH BACKSIDE OF EASTERN TROUGH.
FIRST THINGS FIRST...AND MAY STILL BE DEALING WITH A FEW RAIN/SNOW
SHOWERS EARLY FRIDAY EVENING AS LAST VESTIGES OF TONIGHTS/FRIDAY
SYSTEM (SEE SHORT TERM DISCUSSION) EXIT STAGE RIGHT. INFILTRATION OF
NORTH FLOW DEEP LAYER DRYING AND SURFACE HIGH PRESSURE SHOULD BRING
A QUICK END TO ANY PRECIP...LEAVING OVERNIGHT FRIDAY RIGHT THROUGH
SATURDAY NIGHT DRY WITH GRADUALLY DECREASING CLOUD COVER. WHILE
INCREASING AMOUNTS OF SUNSHINE SATURDAY WILL PARTIALLY OFFSET
MAINTENANCE OF COOL NORTH WINDS...CLEAR SKIES AND QUICK DECOUPLING
OFF LOW LEVEL WINDS WILL ALLOW TEMPERATURES TO DROP RAPIDLY SATURDAY
EVENING. LAST FEW WEEKS HAVE SEEN PLENTY OF SIMILAR SCENARIOS...AND
EACH HAVE RESULTED IN COLDER READINGS THAN GUIDANCE INITIALLY
ANTICIPATED. EXPECT THIS TO BE THE CASE ONCE AGAIN...AND HAVE GONE
AHEAD A CUT LOWS BY SEVERAL DEGREES...WITH MOST INLAND AREAS DOWN
INTO THE 20S BY EARLY SUNDAY MORNING (IF CURRENT TRENDS CONTINUE...
COULD EVEN SEE THE NEED TO LOWER TEMPERATURES A FEW MORE DEGREES IN
THE TYPICAL ICE BOX LOCATIONS).
SOME UNCERTAINTY FOR THE REMAINDER OF THE WEEKEND INTO THE MIDDLE
PORTIONS OF NEXT WEEK...MAINLY CENTERING ON LIGHT PRECIP POTENTIAL
SUNDAY WITH MOISTURE STARVED NORTHERN STREAM WAVE...AND WITH
ADDITIONAL RAIN CHANCES TUESDAY AND WEDNESDAY. AS FOR THE
FORMER...POSITION OF AFOREMENTIONED LARGE SCALE FEATURES SUGGEST
"BEST" DYNAMICS AND WAA FORCED ASCENT REMAINING TO OUR WEST ON
SUNDAY. DRY NORTHEAST LOW LEVEL FLOW ALSO SUGGESTS DRY WEATHER
CONTINUING THROUGH SUNDAY. MAINTENANCE OF NEAR STATIONARY SURFACE
HIGH STILL SUPPORTS A DRY BEGINNING TO NEXT WORK WEEK UNDER MOSTLY
CLEAR TO PARTLY CLOUDY SKIES. TYPICAL SPRINGTIME AIRMASS
MODIFICATION RESULTS IN SOME SLOW WARMING...WITH HIGHS MOSTLY IN THE
LOWER 50S BY MONDAY (A TOUCH COOLER NEAR THE BIG LAKES AND ACROSS
EASTERN UPPER). MUCH UNCERTAINTY REMAINS WITH THE MID WEEK RAIN
POTENTIAL...WITH LATEST (AND RATHER ROCK STEADY) ECMWF SHOWING MUCH
MORE AMPLIFIED AND SLOWER TO LEAVE EASTERN LAKES/EASTERN US TROUGH
THAN OTHER GUIDANCE. ECMWF SOLUTION WOULD EVEN SUGGEST SOME ATLANTIC
MOISTURE PINWHEELING BACK WEST...BRINGING AT LEAST THE THREAT OF
SOME RAINS TO OUR EASTERN AREAS TUESDAY AND TUESDAY NIGHT. THIS DOES
SEEM A TOUCH EXTREME...ALTHOUGH FEEL ITS DEPICTION OF A MORE
AGGRESSIVE EASTERN TROUGH IS VERY PLAUSIBLE. OTHER PROGS...
ESPECIALLY THE SOMEWHAT MORE PROGRESSIVE GFS...WOULD SUGGEST A MID
WEEK SHOWER THREAT VIA ADDITIONAL NORTHERN STREAM ENERGY DROPPING ON
BACKSIDE OF SLOWLY DEPARTING EAST CANADA TROUGH AXIS. CONFIDENCE ON
HOW THIS WILL PLAY OUT REMAINS EXCEPTIONALLY LOW...AND WILL SIMPLY
RIDE WITH A MODEL BLEND APPROACH...FEATURING LOW END RAIN CHANCES
TUESDAY NIGHT INTO WEDNESDAY. TEMPERATURES WILL ALSO BE HIGHLY
DEPENDENT ON HOW THE ABOVE UNFOLDS...WITH SOME POTENTIAL FOR COOL
NORTHERLY FLOW TO CONTINUE. WILL SHOW A SLOW WARMING TREND...BUT
WOULD NOT BE SURPRISED IF THIS...AND RAIN POTENTIAL...SEES
SIGNIFICANT CHANGES IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 143 PM EDT THU APR 19 2012
MID CLOUDS THICKEN LATER THIS AFTERNOON...WITH RAIN MOVING IN FROM
THE SOUTHWEST THIS EVENING WITH IFR CEILINGS EXPECTED TO DEVELOP.
MAY SEE IFR VISIBILITIES IN SNOWFALL AT PLN LATE. LOW LEVEL WIND
SHEAR ALSO A CONCERN AT LEAST AT TVC/MBL TONIGHT.
&&
.MARINE...
ISSUED AT 433 PM EDT THU APR 19 2012
INCREASINGLY GUSTY NORTHEAST WINDS NORTH OF PASSING SOUTHERN LAKES
LOW PRESSURE WILL RESULT IN SCA/S ACROSS MOST NEARSHORE WATERS
BORDERING NORTHERN LOWER MICHIGAN TONIGHT INTO FRIDAY AFTERNOON.
STRONGEST WINDS EXPECTED OVER NORTHERN LAKE HURON LATE TONIGHT INTO
FRIDAY...WITH GALE FORCE WIND GUSTS EXPECTED FROM NEAR THE STRAITS
DOWN TO STURGEON POINT. CONDITIONS WILL IMPROVE FRIDAY NIGHT INTO
THE WEEKEND AS HIGH PRESSURE BUILDS OVERHEAD.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 2 AM TO NOON EDT FRIDAY FOR MIZ008-
015.
LH...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EDT FRIDAY
FOR LHZ345-346-349.
GALE WARNING FROM 5 AM TO 5 PM EDT FRIDAY FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EDT FRIDAY
FOR LMZ323-341-342-344>346.
LS...NONE.
&&
$$
UPDATE...JA
SYNOPSIS...SR
SHORT TERM...JB
LONG TERM...MB
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
158 PM EDT THU APR 19 2012
.UPDATE...
ISSUED AT 930 AM EDT THU APR 19 2012
SUBTLE TROUGH SLIDING ACROSS LAKE SUPERIOR IS PROVIDING JUST ENOUGH
OF A BOOST TO MARGINAL OVER-WATER INSTABILITY /H85 TEMPS -6 LEADING
TO DELTA T/S AROUND 8-9C/ TO KICK OFF SNOW SHOWERS ALONG LK SUPERIOR
WITH SOME RAIN SHOWERS AS WELL. VISIBLE SATELLITE INDICATES ENHANCED
CLOUDS SLIDING NORTH-TO-SOUTH OVR CNTRL LK SUPERIOR. CLOUDS ARE NOT
AS ENHANCED OVR NORTHERN LK SUPERIOR WITH BREAKS DEVELOPING IN THE
CLOUDS ESPECIALLY TOWARD ISLE ROYALE.
ADDED SMALL POPS ALONG LK SUPERIOR MAINLY FM MARQUETTE COUNTY TO
LUCE COUNTY FOR THE MORNING AS ENHANCED CLOUDS/SFC TROUGH MOVES
THROUGH. PRECIP AMOUNTS SHOULD BE LIMITED WITH LIMITED DURATION OF
HEAVIER SHOWERS. SNOW AMOUNTS MINIMAL AS WELL DUE TO PRETTY WARM BLYR
TEMPS CURRENTLY IN THE MIDDLE 30S. EVEN SO...MAY SEE A COATING OF
ACCUMULATION WHERE THE SNOW SHOWERS PERSIST LONGEST. ATTN THIS AFTN
TURNS TO SYSTEM NEARING FM THE PLAINS. MOST CONCENTRATED PRECIP WITH
SYSTEM IS CURRENTLY OVR SOUTHERN MN. NO CHANGES WERE MADE TO AFTN OR
EVENING FCST AT THIS TIME.
&&
.SYNOPSIS...
ISSUED AT 529 AM EDT THU APR 19 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW OVER
THE NRN TIER CONUS TO THE S OF UPR TROF OVER HUDSON BAY. POTENT
SHRTWV/LO PRES RESPONSIBLE FOR RA/WIND ON WED IS NOW HEADING QUICKLY
E INTO QUEBEC...WITH DRIER AIR ALF SHOWN ON THE 00Z INL RAOB AND
WEAK HI PRES RDG MOVING INTO THE UPR LKS BEHIND THIS DEPARTING
DISTURBANCE. EVEN THOUGH THE MID/UPR LVLS ARE QUITE DRY...00Z INL
RAOB INDICATES A GOOD DEAL OF LLVL MSTR LINGERS BLO SHARP SUBSIDENCE
INVRN NEAR H8. SFC OBS/STLT IMAGERY SHOWS LO CLDS LINGERING BACK
INTO THE MN ARROWHEAD...BUT SOME CLRG HAS DVLPD OVER THE SCNTRL
WHERE THE WNW FLOW IN THE WAKE OF THE DEPARTING LO IS DOWNSLOPING.
LOOKING UPSTREAM...A WEAK SHRTWV RDG IS PRESENT IN THE NRN PLAINS...
BUT QUITE A BIT OF MID/HI CLD IS STREAMING EWD TOWARD THE UPR LKS TO
THE E OF THIS FEATURE...WITH THIS MSTR WELL DEPICTED ON THE 00Z
BISMARCK RAOB. WV IMAGERY AND RUC ANALYSIS INDICATE THE PRESENCE OF
SEVERAL OUT OF PHASE SHRTWVS MOVING E INTO THE HI PLAINS BEHIND THE
RDG AXIS THAT APPEAR TO BE CONTRIBUTING TO THIS MID/HI CLD. THERE IS
SOME RA EXTENDING FM THE WRN DAKOTAS INTO NEBRASKA EARLY THIS
MORNING WHERE THE MSTR IS DEEPER PER THE 00Z GLASGOW MONTANA RAOB.
THIS PCPN APPEARS TO BE HEAVIER CLOSER TO THE H85 FRONT NEAR THE
NEBRASKA/SDAKOTA BORDER. A MORE POTENT DISTURBANCE IS EVIDENT OVER
THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
MAIN FCST CONCERNS DURING THIS TIME REVOLVE AROUND IMPACT OF MORE
WELL DEFINED SHRTWV NOW IN THE PAC NW AND THE FRONTAL ZONE THAT WL
BE LEFT BEHIND OVER THE LOWER GREAT LAKES IN THE WAKE OF DEPARTING
LO AND HOW FAR N ACCOMPANYING PCPN...AND WHAT TYPE...WL SPREAD INTO
UPR MI.
TODAY...WITH DRY AIR ALF AND SFC HI PRES MOVING ACRS THE UPR LKS
THIS MRNG...EXPECT DRY WX TO PREVAIL EVEN THOUGH THERE SHOULD BE A
GOOD DEAL OF SC LINGERING NEAR LK SUP. BUT EVEN OVER THE SCNTRL
ZNS...EXTENSIVE MID/HI CLD UPSTREAM SHOULD BRING ABOUT A MOCLDY DAY.
OF MORE CONCERN IS HOW QUICKLY THE RA NOW IN THE HI PLAINS WL SPREAD
INTO THE AREA THIS AFTN AS SRN MOST OF THE LEAD SHRTWVS RIPPLES EWD
ALONG W-E H85 FNT THAT SETS UP OVER THE LOWER GRT LKS. THE 00Z NAM
HAS TRENDED TOWARD THE NON NCEP GUIDANCE...WHICH SHOWS BULK OF PCPN
REMAINING TO THE SW OF THE WI BORDER THRU 00Z. IN FACT...THE NAM IS
NOW COMPLETELY DRY THRU 00Z WITH LLVL NE FLOW ON THE SRN FLANK OF HI
CENTER MOVING ACROSS ONTARIO ADVECTING VERY DRY H85 AIR INTO THE
CWA...WITH CORE OF LOWEST H85 DEWPT OF -16C OVER THE NCNTRL AT 00Z.
NAM FCST NRN EDGE OF THE PCPN LINES UP FAIRLY WELL WITH ITS AXIS OF
SHARPEST H7-5 FGEN...WHICH SEEMS A GOOD BET. EVEN THOUGH THE 00Z GFS
SHOWS H85 DEWPTS IN THE CORE OF THE DRY AIR AS LO AS -25C...THE 00Z
GFS AND NON NCEP MODELS APPEAR TO BROAD BRUSH PCPN TOO FAR N INTO
THE DRIER LLVL AIR AND UNDER FAIRLY IMPRESSIVE UPR DVGC THAT EVEN
THE NAM SHOWS OVER THE SRN HALF OF UPR MI IN RRQ OF H3 JET MAX IN
ONTARIO. WHILE THIS UPR DVGC WL RESULT IN THICKER MID CLD...SUSPECT
THE LLVL DRY AIR WL TEND TO CAUSE THE NRN EDGE OF THE PCPN TO BE
SHARPER THAN DEPICTED BY MANY OF THE MODELS AND LIKELY REMAIN NO
FARTHER N THAN MNM COUNTY CLOSER TO THE H85 FRONT IN THE LOWER LKS.
WEAKNESS OF SHRTWVS IN THE NRN PLAINS ALSO ARGUES FOR HIER POPS TO
BE SUPPRESSED TO THE S. OPTED TO CUT PREVIOUS FCST POPS THAT WERE AS
HI AS LIKELY OVER THE FAR SCNTRL TO NO MORE THAN CHC. THE 00Z GFS
SHOWS THE AXIS OF SHARPEST H7-5 FGEN FARTHER N THAN THE NAM...AND
USED THIS AXIS FOR THE NRN EDGE OF THE CHC POPS. WITH NE FLOW OFF
THE CHILLY WATERS OF LK SUP AND THICKENING CLD COVER...EXPECT WELL
BLO NORMAL HI TEMPS. ALTHOUGH HI TEMPS WL RISE INTO THE 40S...FCST
WBZ HGTS/EVAPORATIVE COOLING INDICATE THE PCPN MAY BE MIXED WITH SN
ON ITS NRN EDGE. BUT ANY PCPN WL BE TOO LGT FOR ANY SN
ACCUMULATION...ESPECIALLY WITH THE WARM SFCS.
TONIGHT...FOCUS REMAINS ON DETERMINING QPF OVER THE FAR SCNTRL AND
THE NRN EDGE OF THE PCPN SHIELD AS SHARPER SHRTWV NOW IN THE PAC NW
DEEPENS THE TROF OVER THE UPR MS RIVER VALLEY AND INDUCES A SOMEWHAT
MORE WELL DEFINED LO PRES ON THE FNT IN THE LOWER LKS. AS THE LLVL
FLOW VEERS TO MORE E ASSOCIATED WITH THIS DVLPG LO...THE CORE OF
DRIEST AIR WL SHIFT TO THE W AS WARMER/MOISTER AIR ARRIVES FM THE
E...AND MODEL CONSENSUS SHOWS PCPN IMPACTING MAINLY THE SE HALF OF
THE CWA WITH LARGER SCALE QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET
MAX TO THE NE IN PLAY. USED THE AXIS OF SHARPEST NAM/GFS H7-5 FGEN
TO DEFINE A SHARPER NW EDGE TO THE PCPN SHIELD ACRS THE CENTRAL ZNS.
AS FAR AS QPF OVER THE SE ZNS IS CONCERNED...00Z NAM/GFS MODELS
SHOW AS MUCH AS 0.75 TO 1.00 INCH QPF AT MNM NEAR THE NRN EDGE OF
THE PCPN SHIELD EVEN THOUGH SHARPER H85-7 FGEN/H85 THERMAL GRADIENT
REMAINS TO THE S OF THAT LOCATION. SINCE DYNAMIC/EVAPORATIVE COOLING
FAVORS THE MORE AGGRESSIVE COOLING SHOWN BY THE NAM WITH NOCTURNAL
COOLING...PREFER ITS FCST H100-85 THKNS LOWERING FASTER TO SUG RA
CHANGING TO SN OVER THE S HALF OF MNM COUNTY. THIS SCENARIO IS IN
GOOD AGREEMENT WITH THE NCEP GUIDANCE...WHICH PAINTS 2 TO 4 INCHES
IN THIS AREA. SINCE MODEL QPF IS LIKELY OVERDONE TO THE N AT IMT AND
BEYOND...DID NOT EXTEND THE ADVY FARTHER TO THE N. GUIDANCE SUGS
MORE LLVL WARMING OVER THE ERN ZNS...SO DID NOT INCLUDE THAT AREA IN
THE ADVY WITH PTYPE MORE LIKELY TO STAY RA THERE LONGER. AFTER
COORDINATION WITH THE GRB OFFICE...OPTED TO ISSUE WINTER WX ADVY FOR
MNM COUNTY FOR 03Z-12Z.
FRI...EXPECT PCPN TO DIMINISH IN THE MRNG AS LO PRES SLIDES TO THE E
INTO THE LOWER GREAT LAKES AND DEERER MSTR/DYNAMICS EXIT TO THE E.
PER NCEP GUIDANCE...DID NOT FOLLOW THE SLOWER CNDN MODEL...WHICH
INDICATES HEAVIER PCPN WOULD LINGER LONGER. AS HIGH PRES BUILDS INTO
THE AREA IN THE WAKE OF THE LO PRES...EXPECT INCRSG SUNSHINE. BUT
STEADY WIND OFF THE CHILLY WATERS OF LK SUP WL CAUSE TEMPS TO RUN
BLO NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
CANADIAN HIGH PRESSURE BUILDING SOUTH OVER THE AREA FRIDAY NIGHT
INTO SATURDAY NIGHT WILL RESULT IN GENERALLY DRY BUT COOLER WEATHER.
850MB TEMPERATURES FALLING TO AROUND -6C ON SATURDAY IN A NRLY FLOW
WILL YIELD HIGH TEMPS ONLY IN THE 40S FOR MOST AREAS...EXCEPT
POSSIBLY APPROACHING 50F IN A FEW SPOTS ALONG THE WI BDR. SHORTWAVE
APPROACHING THE AREA IN A NW FLOW ALOFT COULD BRING IN A MIX OF
LIGHT RAIN/SNOW SHOWERS OVER THE WRN COUNTIES LATE SATURDAY NIGHT
INTO SUNDAY. AGAIN NOT EXPECTING MUCH PCPN AS MOISTURE LOOKS TO
BE LIMITED AHEAD OF THE SHORTWAVE AND FORCING WILL BE GENERALLY
WEAK.
MODELS SHOW TROUGH OVER THE WRN COUNTIES DISSIPATING LATE SUNDAY AS
THE HIGH PRESSURE RIDGE BUILDS BACK OVER THE AREA FOR THE EARLY PART
OF NEXT WEEK. AIRMASS GENERALLY MODIFIES AS HIGH TEMPS REBOUND INTO
THE 50S OVER MUCH OF THE AREA BY TUESDAY. MODELS HINT AT ANOTHER
SHORTWAVE APPROACHING FROM THE WEST TUE NIGHT INTO WEDNESDAY AS IT
RIDES OVER MID-UPR LVL RDG IN PLACE. NOT CONFIDENT THIS FEATURE
WILL PRODUCE MUCH PCPN AS IT LOOKS LIKE BEST FORCING WAA/ISENTROPIC
LIFT WILL STAY WELL NORTH OF THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 153 PM EDT THU APR 19 2012
COMPACT SFC-MID LEVEL LOW PRESSURE SYSTEM FCST TO BRING BAND OF
HEAVY PRECIPITATION /MAINLY IN THE FORM OF SNOW/ SOMEWHERE IN NARROW
BAND BETWEEN WI/LOWER MI AND THE TERMINALS OVR UPR MI. APPEARS THAT
SIGNIFICANT SNOW WILL NOT IMPACT ANY OF THE TERMINAL SITES IN UPR
MI...BUT IT COULD AFFECT ENROUTE TRAFFIC FM THE SOUTH TONIGHT. IN
THE MEANTIME...STUBBORN STRATOCU WILL TRY AND SCT OUT BY LATE AFTN.
EVENTUALLY...MID-HIGH CLOUDS SPREAD INTO UPR MI FM THE SOUTHWEST
THIS EVENING. EVEN THESE CLOUDS MAY STAY CLEAR OF KCMX THOUGH. ON
FRIDAY MORNING...THERE COULD BE SOME SNOW TRY TO PUSH INTO THE SAW
TERMINAL FM THE SOUTH BUT THIS APPEARS TO BE A LOW CHANCE AT THIS
POINT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 529 AM EDT THU APR 19 2012
AS HI PRES BUILDS OVER LK SUP TODAY...EXPECT DIMINISHING NW WINDS
VEERING N TO NE. A LO PRES WILL TRACK THRU THE LOWER GREAT LAKES
LATE TONIGHT INTO FRI MORNING. SINCE THE SHARPER PRES GRADIENT WILL
REMAIN TO THE S...EXPECT NE WINDS NO HIGHER THAN 20 KTS OR SO OVER
THE SCENTRAL AND E. PERSISTENT HIGH PRESSURE OVER THE AREA WILL KEEP
WINDS LESS THAN 20 KTS FRI NIGHT INTO MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 AM CDT
FRIDAY FOR MIZ012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...JLA
MARINE...KC/VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
931 AM EDT THU APR 19 2012
.UPDATE...
ISSUED AT 930 AM EDT THU APR 19 2012
SUBTLE TROUGH SLIDING ACROSS LAKE SUPERIOR IS PROVIDING JUST ENOUGH
OF A BOOST TO MARGINAL OVER-WATER INSTABILITY /H85 TEMPS -6 LEADING
TO DELTA T/S AROUND 8-9C/ TO KICK OFF SNOW SHOWERS ALONG LK SUPERIOR
WITH SOME RAIN SHOWERS AS WELL. VISIBLE SATELLITE INDICATES ENHANCED
CLOUDS SLIDING NORTH-TO-SOUTH OVR CNTRL LK SUPERIOR. CLOUDS ARE NOT
AS ENHANCED OVR NORTHERN LK SUPERIOR WITH BREAKS DEVELOPING IN THE
CLOUDS ESPECIALLY TOWARD ISLE ROYALE.
ADDED SMALL POPS ALONG LK SUPERIOR MAINLY FM MARQUETTE COUNTY TO
LUCE COUNTY FOR THE MORNING AS ENHANCED CLOUDS/SFC TROUGH MOVES
THROUGH. PRECIP AMOUNTS SHOULD BE LIMITED WITH LIMITED DURATION OF
HEAVIER SHOWERS. SNOW AMOUNTS MINIMAL AS WELL DUE TO PRETTY WARM BLYR
TEMPS CURRENTLY IN THE MIDDLE 30S. EVEN SO...MAY SEE A COATING OF
ACCUMULATION WHERE THE SNOW SHOWERS PERSIST LONGEST. ATTN THIS AFTN
TURNS TO SYSTEM NEARING FM THE PLAINS. MOST CONCENTRATED PRECIP WITH
SYSTEM IS CURRENTLY OVR SOUTHERN MN. NO CHANGES WERE MADE TO AFTN OR
EVENING FCST AT THIS TIME. &&
.SYNOPSIS...
ISSUED AT 529 AM EDT THU APR 19 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW OVER
THE NRN TIER CONUS TO THE S OF UPR TROF OVER HUDSON BAY. POTENT
SHRTWV/LO PRES RESPONSIBLE FOR RA/WIND ON WED IS NOW HEADING QUICKLY
E INTO QUEBEC...WITH DRIER AIR ALF SHOWN ON THE 00Z INL RAOB AND
WEAK HI PRES RDG MOVING INTO THE UPR LKS BEHIND THIS DEPARTING
DISTURBANCE. EVEN THOUGH THE MID/UPR LVLS ARE QUITE DRY...00Z INL
RAOB INDICATES A GOOD DEAL OF LLVL MSTR LINGERS BLO SHARP SUBSIDENCE
INVRN NEAR H8. SFC OBS/STLT IMAGERY SHOWS LO CLDS LINGERING BACK
INTO THE MN ARROWHEAD...BUT SOME CLRG HAS DVLPD OVER THE SCNTRL
WHERE THE WNW FLOW IN THE WAKE OF THE DEPARTING LO IS DOWNSLOPING.
LOOKING UPSTREAM...A WEAK SHRTWV RDG IS PRESENT IN THE NRN PLAINS...
BUT QUITE A BIT OF MID/HI CLD IS STREAMING EWD TOWARD THE UPR LKS TO
THE E OF THIS FEATURE...WITH THIS MSTR WELL DEPICTED ON THE 00Z
BISMARCK RAOB. WV IMAGERY AND RUC ANALYSIS INDICATE THE PRESENCE OF
SEVERAL OUT OF PHASE SHRTWVS MOVING E INTO THE HI PLAINS BEHIND THE
RDG AXIS THAT APPEAR TO BE CONTRIBUTING TO THIS MID/HI CLD. THERE IS
SOME RA EXTENDING FM THE WRN DAKOTAS INTO NEBRASKA EARLY THIS
MORNING WHERE THE MSTR IS DEEPER PER THE 00Z GLASGOW MONTANA RAOB.
THIS PCPN APPEARS TO BE HEAVIER CLOSER TO THE H85 FRONT NEAR THE
NEBRASKA/SDAKOTA BORDER. A MORE POTENT DISTURBANCE IS EVIDENT OVER
THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
MAIN FCST CONCERNS DURING THIS TIME REVOLVE AROUND IMPACT OF MORE
WELL DEFINED SHRTWV NOW IN THE PAC NW AND THE FRONTAL ZONE THAT WL
BE LEFT BEHIND OVER THE LOWER GREAT LAKES IN THE WAKE OF DEPARTING
LO AND HOW FAR N ACCOMPANYING PCPN...AND WHAT TYPE...WL SPREAD INTO
UPR MI.
TODAY...WITH DRY AIR ALF AND SFC HI PRES MOVING ACRS THE UPR LKS
THIS MRNG...EXPECT DRY WX TO PREVAIL EVEN THOUGH THERE SHOULD BE A
GOOD DEAL OF SC LINGERING NEAR LK SUP. BUT EVEN OVER THE SCNTRL
ZNS...EXTENSIVE MID/HI CLD UPSTREAM SHOULD BRING ABOUT A MOCLDY DAY.
OF MORE CONCERN IS HOW QUICKLY THE RA NOW IN THE HI PLAINS WL SPREAD
INTO THE AREA THIS AFTN AS SRN MOST OF THE LEAD SHRTWVS RIPPLES EWD
ALONG W-E H85 FNT THAT SETS UP OVER THE LOWER GRT LKS. THE 00Z NAM
HAS TRENDED TOWARD THE NON NCEP GUIDANCE...WHICH SHOWS BULK OF PCPN
REMAINING TO THE SW OF THE WI BORDER THRU 00Z. IN FACT...THE NAM IS
NOW COMPLETELY DRY THRU 00Z WITH LLVL NE FLOW ON THE SRN FLANK OF HI
CENTER MOVING ACROSS ONTARIO ADVECTING VERY DRY H85 AIR INTO THE
CWA...WITH CORE OF LOWEST H85 DEWPT OF -16C OVER THE NCNTRL AT 00Z.
NAM FCST NRN EDGE OF THE PCPN LINES UP FAIRLY WELL WITH ITS AXIS OF
SHARPEST H7-5 FGEN...WHICH SEEMS A GOOD BET. EVEN THOUGH THE 00Z GFS
SHOWS H85 DEWPTS IN THE CORE OF THE DRY AIR AS LO AS -25C...THE 00Z
GFS AND NON NCEP MODELS APPEAR TO BROAD BRUSH PCPN TOO FAR N INTO
THE DRIER LLVL AIR AND UNDER FAIRLY IMPRESSIVE UPR DVGC THAT EVEN
THE NAM SHOWS OVER THE SRN HALF OF UPR MI IN RRQ OF H3 JET MAX IN
ONTARIO. WHILE THIS UPR DVGC WL RESULT IN THICKER MID CLD...SUSPECT
THE LLVL DRY AIR WL TEND TO CAUSE THE NRN EDGE OF THE PCPN TO BE
SHARPER THAN DEPICTED BY MANY OF THE MODELS AND LIKELY REMAIN NO
FARTHER N THAN MNM COUNTY CLOSER TO THE H85 FRONT IN THE LOWER LKS.
WEAKNESS OF SHRTWVS IN THE NRN PLAINS ALSO ARGUES FOR HIER POPS TO
BE SUPPRESSED TO THE S. OPTED TO CUT PREVIOUS FCST POPS THAT WERE AS
HI AS LIKELY OVER THE FAR SCNTRL TO NO MORE THAN CHC. THE 00Z GFS
SHOWS THE AXIS OF SHARPEST H7-5 FGEN FARTHER N THAN THE NAM...AND
USED THIS AXIS FOR THE NRN EDGE OF THE CHC POPS. WITH NE FLOW OFF
THE CHILLY WATERS OF LK SUP AND THICKENING CLD COVER...EXPECT WELL
BLO NORMAL HI TEMPS. ALTHOUGH HI TEMPS WL RISE INTO THE 40S...FCST
WBZ HGTS/EVAPORATIVE COOLING INDICATE THE PCPN MAY BE MIXED WITH SN
ON ITS NRN EDGE. BUT ANY PCPN WL BE TOO LGT FOR ANY SN
ACCUMULATION...ESPECIALLY WITH THE WARM SFCS.
TONIGHT...FOCUS REMAINS ON DETERMINING QPF OVER THE FAR SCNTRL AND
THE NRN EDGE OF THE PCPN SHIELD AS SHARPER SHRTWV NOW IN THE PAC NW
DEEPENS THE TROF OVER THE UPR MS RIVER VALLEY AND INDUCES A SOMEWHAT
MORE WELL DEFINED LO PRES ON THE FNT IN THE LOWER LKS. AS THE LLVL
FLOW VEERS TO MORE E ASSOCIATED WITH THIS DVLPG LO...THE CORE OF
DRIEST AIR WL SHIFT TO THE W AS WARMER/MOISTER AIR ARRIVES FM THE
E...AND MODEL CONSENSUS SHOWS PCPN IMPACTING MAINLY THE SE HALF OF
THE CWA WITH LARGER SCALE QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET
MAX TO THE NE IN PLAY. USED THE AXIS OF SHARPEST NAM/GFS H7-5 FGEN
TO DEFINE A SHARPER NW EDGE TO THE PCPN SHIELD ACRS THE CENTRAL ZNS.
AS FAR AS QPF OVER THE SE ZNS IS CONCERNED...00Z NAM/GFS MODELS
SHOW AS MUCH AS 0.75 TO 1.00 INCH QPF AT MNM NEAR THE NRN EDGE OF
THE PCPN SHIELD EVEN THOUGH SHARPER H85-7 FGEN/H85 THERMAL GRADIENT
REMAINS TO THE S OF THAT LOCATION. SINCE DYNAMIC/EVAPORATIVE COOLING
FAVORS THE MORE AGGRESSIVE COOLING SHOWN BY THE NAM WITH NOCTURNAL
COOLING...PREFER ITS FCST H100-85 THKNS LOWERING FASTER TO SUG RA
CHANGING TO SN OVER THE S HALF OF MNM COUNTY. THIS SCENARIO IS IN
GOOD AGREEMENT WITH THE NCEP GUIDANCE...WHICH PAINTS 2 TO 4 INCHES
IN THIS AREA. SINCE MODEL QPF IS LIKELY OVERDONE TO THE N AT IMT AND
BEYOND...DID NOT EXTEND THE ADVY FARTHER TO THE N. GUIDANCE SUGS
MORE LLVL WARMING OVER THE ERN ZNS...SO DID NOT INCLUDE THAT AREA IN
THE ADVY WITH PTYPE MORE LIKELY TO STAY RA THERE LONGER. AFTER
COORDINATION WITH THE GRB OFFICE...OPTED TO ISSUE WINTER WX ADVY FOR
MNM COUNTY FOR 03Z-12Z.
FRI...EXPECT PCPN TO DIMINISH IN THE MRNG AS LO PRES SLIDES TO THE E
INTO THE LOWER GREAT LAKES AND DEERER MSTR/DYNAMICS EXIT TO THE E.
PER NCEP GUIDANCE...DID NOT FOLLOW THE SLOWER CNDN MODEL...WHICH
INDICATES HEAVIER PCPN WOULD LINGER LONGER. AS HIGH PRES BUILDS INTO
THE AREA IN THE WAKE OF THE LO PRES...EXPECT INCRSG SUNSHINE. BUT
STEADY WIND OFF THE CHILLY WATERS OF LK SUP WL CAUSE TEMPS TO RUN
BLO NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
CANADIAN HIGH PRESSURE BUILDING SOUTH OVER THE AREA FRIDAY NIGHT
INTO SATURDAY NIGHT WILL RESULT IN GENERALLY DRY BUT COOLER WEATHER.
850MB TEMPERATURES FALLING TO AROUND -6C ON SATURDAY IN A NRLY FLOW
WILL YIELD HIGH TEMPS ONLY IN THE 40S FOR MOST AREAS...EXCEPT
POSSIBLY APPROACHING 50F IN A FEW SPOTS ALONG THE WI BDR. SHORTWAVE
APPROACHING THE AREA IN A NW FLOW ALOFT COULD BRING IN A MIX OF
LIGHT RAIN/SNOW SHOWERS OVER THE WRN COUNTIES LATE SATURDAY NIGHT
INTO SUNDAY. AGAIN NOT EXPECTING MUCH PCPN AS MOISTURE LOOKS TO
BE LIMITED AHEAD OF THE SHORTWAVE AND FORCING WILL BE GENERALLY
WEAK.
MODELS SHOW TROUGH OVER THE WRN COUNTIES DISSIPATING LATE SUNDAY AS
THE HIGH PRESSURE RIDGE BUILDS BACK OVER THE AREA FOR THE EARLY PART
OF NEXT WEEK. AIRMASS GENERALLY MODIFIES AS HIGH TEMPS REBOUND INTO
THE 50S OVER MUCH OF THE AREA BY TUESDAY. MODELS HINT AT ANOTHER
SHORTWAVE APPROACHING FROM THE WEST TUE NIGHT INTO WEDNESDAY AS IT
RIDES OVER MID-UPR LVL RDG IN PLACE. NOT CONFIDENT THIS FEATURE
WILL PRODUCE MUCH PCPN AS IT LOOKS LIKE BEST FORCING WAA/ISENTROPIC
LIFT WILL STAY WELL NORTH OF THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 736 AM EDT THU APR 19 2012
THE COMBINATION OF HIGH PRESSURE BUILDING IN FM ONTARIO AND
INCREASING SUN ANGLE SHOULD HELP SLOWLY ERODE MVFR CLOUD DECK AT TAF
SITES BY EARLY AFTERNOON DESPITE NE FLOW OFF LAKE SUPERIOR. PCPN
FROM SYSTEM APPROACHING OVER THE PLAINS WILL STAY SOUTH AND EAST OF
KIWD AND KCMX ALTHOUGH THEY WILL SEE SOME INCREASE IN MID-HIGH
CLOUDS LATE IN THE DAY AND TONIGHT. KSAW WILL BE ON THE NW EDGE OF
THE PCPN LATER TONIGHT. INCREASE IN LOW-LVL MOISTURE ALONG WITH
CONTINUED NE FLOW OFF LAKE SUPERIOR SHOULD ALLOW FOR MVFR CLOUD DECK
AND POSSIBLE FLURRIES TO DEVELOP MAINLY AFT 08Z.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 529 AM EDT THU APR 19 2012
AS HI PRES BUILDS OVER LK SUP TODAY...EXPECT DIMINISHING NW WINDS
VEERING N TO NE. A LO PRES WILL TRACK THRU THE LOWER GREAT LAKES
LATE TONIGHT INTO FRI MORNING. SINCE THE SHARPER PRES GRADIENT WILL
REMAIN TO THE S...EXPECT NE WINDS NO HIGHER THAN 20 KTS OR SO OVER
THE SCENTRAL AND E. PERSISTENT HIGH PRESSURE OVER THE AREA WILL KEEP
WINDS LESS THAN 20 KTS FRI NIGHT INTO MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 AM CDT
FRIDAY FOR MIZ012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...VOSS
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
754 AM EDT THU APR 19 2012
.SYNOPSIS...
ISSUED AT 529 AM EDT THU APR 19 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW OVER
THE NRN TIER CONUS TO THE S OF UPR TROF OVER HUDSON BAY. POTENT
SHRTWV/LO PRES RESPONSIBLE FOR RA/WIND ON WED IS NOW HEADING QUICKLY
E INTO QUEBEC...WITH DRIER AIR ALF SHOWN ON THE 00Z INL RAOB AND
WEAK HI PRES RDG MOVING INTO THE UPR LKS BEHIND THIS DEPARTING
DISTURBANCE. EVEN THOUGH THE MID/UPR LVLS ARE QUITE DRY...00Z INL
RAOB INDICATES A GOOD DEAL OF LLVL MSTR LINGERS BLO SHARP SUBSIDENCE
INVRN NEAR H8. SFC OBS/STLT IMAGERY SHOWS LO CLDS LINGERING BACK
INTO THE MN ARROWHEAD...BUT SOME CLRG HAS DVLPD OVER THE SCNTRL
WHERE THE WNW FLOW IN THE WAKE OF THE DEPARTING LO IS DOWNSLOPING.
LOOKING UPSTREAM...A WEAK SHRTWV RDG IS PRESENT IN THE NRN PLAINS...
BUT QUITE A BIT OF MID/HI CLD IS STREAMING EWD TOWARD THE UPR LKS TO
THE E OF THIS FEATURE...WITH THIS MSTR WELL DEPICTED ON THE 00Z
BISMARCK RAOB. WV IMAGERY AND RUC ANALYSIS INDICATE THE PRESENCE OF
SEVERAL OUT OF PHASE SHRTWVS MOVING E INTO THE HI PLAINS BEHIND THE
RDG AXIS THAT APPEAR TO BE CONTRIBUTING TO THIS MID/HI CLD. THERE IS
SOME RA EXTENDING FM THE WRN DAKOTAS INTO NEBRASKA EARLY THIS
MORNING WHERE THE MSTR IS DEEPER PER THE 00Z GLASGOW MONTANA RAOB.
THIS PCPN APPEARS TO BE HEAVIER CLOSER TO THE H85 FRONT NEAR THE
NEBRASKA/SDAKOTA BORDER. A MORE POTENT DISTURBANCE IS EVIDENT OVER
THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
MAIN FCST CONCERNS DURING THIS TIME REVOLVE AROUND IMPACT OF MORE
WELL DEFINED SHRTWV NOW IN THE PAC NW AND THE FRONTAL ZONE THAT WL
BE LEFT BEHIND OVER THE LOWER GREAT LAKES IN THE WAKE OF DEPARTING
LO AND HOW FAR N ACCOMPANYING PCPN...AND WHAT TYPE...WL SPREAD INTO
UPR MI.
TODAY...WITH DRY AIR ALF AND SFC HI PRES MOVING ACRS THE UPR LKS
THIS MRNG...EXPECT DRY WX TO PREVAIL EVEN THOUGH THERE SHOULD BE A
GOOD DEAL OF SC LINGERING NEAR LK SUP. BUT EVEN OVER THE SCNTRL
ZNS...EXTENSIVE MID/HI CLD UPSTREAM SHOULD BRING ABOUT A MOCLDY DAY.
OF MORE CONCERN IS HOW QUICKLY THE RA NOW IN THE HI PLAINS WL SPREAD
INTO THE AREA THIS AFTN AS SRN MOST OF THE LEAD SHRTWVS RIPPLES EWD
ALONG W-E H85 FNT THAT SETS UP OVER THE LOWER GRT LKS. THE 00Z NAM
HAS TRENDED TOWARD THE NON NCEP GUIDANCE...WHICH SHOWS BULK OF PCPN
REMAINING TO THE SW OF THE WI BORDER THRU 00Z. IN FACT...THE NAM IS
NOW COMPLETELY DRY THRU 00Z WITH LLVL NE FLOW ON THE SRN FLANK OF HI
CENTER MOVING ACROSS ONTARIO ADVECTING VERY DRY H85 AIR INTO THE
CWA...WITH CORE OF LOWEST H85 DEWPT OF -16C OVER THE NCNTRL AT 00Z.
NAM FCST NRN EDGE OF THE PCPN LINES UP FAIRLY WELL WITH ITS AXIS OF
SHARPEST H7-5 FGEN...WHICH SEEMS A GOOD BET. EVEN THOUGH THE 00Z GFS
SHOWS H85 DEWPTS IN THE CORE OF THE DRY AIR AS LO AS -25C...THE 00Z
GFS AND NON NCEP MODELS APPEAR TO BROAD BRUSH PCPN TOO FAR N INTO
THE DRIER LLVL AIR AND UNDER FAIRLY IMPRESSIVE UPR DVGC THAT EVEN
THE NAM SHOWS OVER THE SRN HALF OF UPR MI IN RRQ OF H3 JET MAX IN
ONTARIO. WHILE THIS UPR DVGC WL RESULT IN THICKER MID CLD...SUSPECT
THE LLVL DRY AIR WL TEND TO CAUSE THE NRN EDGE OF THE PCPN TO BE
SHARPER THAN DEPICTED BY MANY OF THE MODELS AND LIKELY REMAIN NO
FARTHER N THAN MNM COUNTY CLOSER TO THE H85 FRONT IN THE LOWER LKS.
WEAKNESS OF SHRTWVS IN THE NRN PLAINS ALSO ARGUES FOR HIER POPS TO
BE SUPPRESSED TO THE S. OPTED TO CUT PREVIOUS FCST POPS THAT WERE AS
HI AS LIKELY OVER THE FAR SCNTRL TO NO MORE THAN CHC. THE 00Z GFS
SHOWS THE AXIS OF SHARPEST H7-5 FGEN FARTHER N THAN THE NAM...AND
USED THIS AXIS FOR THE NRN EDGE OF THE CHC POPS. WITH NE FLOW OFF
THE CHILLY WATERS OF LK SUP AND THICKENING CLD COVER...EXPECT WELL
BLO NORMAL HI TEMPS. ALTHOUGH HI TEMPS WL RISE INTO THE 40S...FCST
WBZ HGTS/EVAPORATIVE COOLING INDICATE THE PCPN MAY BE MIXED WITH SN
ON ITS NRN EDGE. BUT ANY PCPN WL BE TOO LGT FOR ANY SN
ACCUMULATION...ESPECIALLY WITH THE WARM SFCS.
TONIGHT...FOCUS REMAINS ON DETERMINING QPF OVER THE FAR SCNTRL AND
THE NRN EDGE OF THE PCPN SHIELD AS SHARPER SHRTWV NOW IN THE PAC NW
DEEPENS THE TROF OVER THE UPR MS RIVER VALLEY AND INDUCES A SOMEWHAT
MORE WELL DEFINED LO PRES ON THE FNT IN THE LOWER LKS. AS THE LLVL
FLOW VEERS TO MORE E ASSOCIATED WITH THIS DVLPG LO...THE CORE OF
DRIEST AIR WL SHIFT TO THE W AS WARMER/MOISTER AIR ARRIVES FM THE
E...AND MODEL CONSENSUS SHOWS PCPN IMPACTING MAINLY THE SE HALF OF
THE CWA WITH LARGER SCALE QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET
MAX TO THE NE IN PLAY. USED THE AXIS OF SHARPEST NAM/GFS H7-5 FGEN
TO DEFINE A SHARPER NW EDGE TO THE PCPN SHIELD ACRS THE CENTRAL ZNS.
AS FAR AS QPF OVER THE SE ZNS IS CONCERNED...00Z NAM/GFS MODELS
SHOW AS MUCH AS 0.75 TO 1.00 INCH QPF AT MNM NEAR THE NRN EDGE OF
THE PCPN SHIELD EVEN THOUGH SHARPER H85-7 FGEN/H85 THERMAL GRADIENT
REMAINS TO THE S OF THAT LOCATION. SINCE DYNAMIC/EVAPORATIVE COOLING
FAVORS THE MORE AGGRESSIVE COOLING SHOWN BY THE NAM WITH NOCTURNAL
COOLING...PREFER ITS FCST H100-85 THKNS LOWERING FASTER TO SUG RA
CHANGING TO SN OVER THE S HALF OF MNM COUNTY. THIS SCENARIO IS IN
GOOD AGREEMENT WITH THE NCEP GUIDANCE...WHICH PAINTS 2 TO 4 INCHES
IN THIS AREA. SINCE MODEL QPF IS LIKELY OVERDONE TO THE N AT IMT AND
BEYOND...DID NOT EXTEND THE ADVY FARTHER TO THE N. GUIDANCE SUGS
MORE LLVL WARMING OVER THE ERN ZNS...SO DID NOT INCLUDE THAT AREA IN
THE ADVY WITH PTYPE MORE LIKELY TO STAY RA THERE LONGER. AFTER
COORDINATION WITH THE GRB OFFICE...OPTED TO ISSUE WINTER WX ADVY FOR
MNM COUNTY FOR 03Z-12Z.
FRI...EXPECT PCPN TO DIMINISH IN THE MRNG AS LO PRES SLIDES TO THE E
INTO THE LOWER GREAT LAKES AND DEERER MSTR/DYNAMICS EXIT TO THE E.
PER NCEP GUIDANCE...DID NOT FOLLOW THE SLOWER CNDN MODEL...WHICH
INDICATES HEAVIER PCPN WOULD LINGER LONGER. AS HIGH PRES BUILDS INTO
THE AREA IN THE WAKE OF THE LO PRES...EXPECT INCRSG SUNSHINE. BUT
STEADY WIND OFF THE CHILLY WATERS OF LK SUP WL CAUSE TEMPS TO RUN
BLO NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
CANADIAN HIGH PRESSURE BUILDING SOUTH OVER THE AREA FRIDAY NIGHT
INTO SATURDAY NIGHT WILL RESULT IN GENERALLY DRY BUT COOLER WEATHER.
850MB TEMPERATURES FALLING TO AROUND -6C ON SATURDAY IN A NRLY FLOW
WILL YIELD HIGH TEMPS ONLY IN THE 40S FOR MOST AREAS...EXCEPT
POSSIBLY APPROACHING 50F IN A FEW SPOTS ALONG THE WI BDR. SHORTWAVE
APPROACHING THE AREA IN A NW FLOW ALOFT COULD BRING IN A MIX OF
LIGHT RAIN/SNOW SHOWERS OVER THE WRN COUNTIES LATE SATURDAY NIGHT
INTO SUNDAY. AGAIN NOT EXPECTING MUCH PCPN AS MOISTURE LOOKS TO
BE LIMITED AHEAD OF THE SHORTWAVE AND FORCING WILL BE GENERALLY
WEAK.
MODELS SHOW TROUGH OVER THE WRN COUNTIES DISSIPATING LATE SUNDAY AS
THE HIGH PRESSURE RIDGE BUILDS BACK OVER THE AREA FOR THE EARLY PART
OF NEXT WEEK. AIRMASS GENERALLY MODIFIES AS HIGH TEMPS REBOUND INTO
THE 50S OVER MUCH OF THE AREA BY TUESDAY. MODELS HINT AT ANOTHER
SHORTWAVE APPROACHING FROM THE WEST TUE NIGHT INTO WEDNESDAY AS IT
RIDES OVER MID-UPR LVL RDG IN PLACE. NOT CONFIDENT THIS FEATURE
WILL PRODUCE MUCH PCPN AS IT LOOKS LIKE BEST FORCING WAA/ISENTROPIC
LIFT WILL STAY WELL NORTH OF THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 736 AM EDT THU APR 19 2012
THE COMBINATION OF HIGH PRESSURE BUILDING IN FM ONTARIO AND
INCREASING SUN ANGLE SHOULD HELP SLOWLY ERODE MVFR CLOUD DECK AT TAF
SITES BY EARLY AFTERNOON DESPITE NE FLOW OFF LAKE SUPERIOR. PCPN
FROM SYSTEM APPROACHING OVER THE PLAINS WILL STAY SOUTH AND EAST OF
KIWD AND KCMX ALTHOUGH THEY WILL SEE SOME INCREASE IN MID-HIGH
CLOUDS LATE IN THE DAY AND TONIGHT. KSAW WILL BE ON THE NW EDGE OF
THE PCPN LATER TONIGHT. INCREASE IN LOW-LVL MOISTURE ALONG WITH
CONTINUED NE FLOW OFF LAKE SUPERIOR SHOULD ALLOW FOR MVFR CLOUD DECK
AND POSSIBLE FLURRIES TO DEVELOP MAINLY AFT 08Z.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 529 AM EDT THU APR 19 2012
AS HI PRES BUILDS OVER LK SUP TODAY...EXPECT DIMINISHING NW WINDS
VEERING N TO NE. A LO PRES WILL TRACK THRU THE LOWER GREAT LAKES
LATE TONIGHT INTO FRI MORNING. SINCE THE SHARPER PRES GRADIENT WILL
REMAIN TO THE S...EXPECT NE WINDS NO HIGHER THAN 20 KTS OR SO OVER
THE SCENTRAL AND E. PERSISTENT HIGH PRESSURE OVER THE AREA WILL KEEP
WINDS LESS THAN 20 KTS FRI NIGHT INTO MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 AM CDT
FRIDAY FOR MIZ012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...VOSS
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
531 AM EDT THU APR 19 2012
.SYNOPSIS...
ISSUED AT 529 AM EDT THU APR 19 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW OVER
THE NRN TIER CONUS TO THE S OF UPR TROF OVER HUDSON BAY. POTENT
SHRTWV/LO PRES RESPONSIBLE FOR RA/WIND ON WED IS NOW HEADING QUICKLY
E INTO QUEBEC...WITH DRIER AIR ALF SHOWN ON THE 00Z INL RAOB AND
WEAK HI PRES RDG MOVING INTO THE UPR LKS BEHIND THIS DEPARTING
DISTURBANCE. EVEN THOUGH THE MID/UPR LVLS ARE QUITE DRY...00Z INL
RAOB INDICATES A GOOD DEAL OF LLVL MSTR LINGERS BLO SHARP SUBSIDENCE
INVRN NEAR H8. SFC OBS/STLT IMAGERY SHOWS LO CLDS LINGERING BACK
INTO THE MN ARROWHEAD...BUT SOME CLRG HAS DVLPD OVER THE SCNTRL
WHERE THE WNW FLOW IN THE WAKE OF THE DEPARTING LO IS DOWNSLOPING.
LOOKING UPSTREAM...A WEAK SHRTWV RDG IS PRESENT IN THE NRN PLAINS...
BUT QUITE A BIT OF MID/HI CLD IS STREAMING EWD TOWARD THE UPR LKS TO
THE E OF THIS FEATURE...WITH THIS MSTR WELL DEPICTED ON THE 00Z
BISMARCK RAOB. WV IMAGERY AND RUC ANALYSIS INDICATE THE PRESENCE OF
SEVERAL OUT OF PHASE SHRTWVS MOVING E INTO THE HI PLAINS BEHIND THE
RDG AXIS THAT APPEAR TO BE CONTRIBUTING TO THIS MID/HI CLD. THERE IS
SOME RA EXTENDING FM THE WRN DAKOTAS INTO NEBRASKA EARLY THIS
MORNING WHERE THE MSTR IS DEEPER PER THE 00Z GLASGOW MONTANA RAOB.
THIS PCPN APPEARS TO BE HEAVIER CLOSER TO THE H85 FRONT NEAR THE
NEBRASKA/SDAKOTA BORDER. A MORE POTENT DISTURBANCE IS EVIDENT OVER
THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
MAIN FCST CONCERNS DURING THIS TIME REVOLVE AROUND IMPACT OF MORE
WELL DEFINED SHRTWV NOW IN THE PAC NW AND THE FRONTAL ZONE THAT WL
BE LEFT BEHIND OVER THE LOWER GREAT LAKES IN THE WAKE OF DEPARTING
LO AND HOW FAR N ACCOMPANYING PCPN...AND WHAT TYPE...WL SPREAD INTO
UPR MI.
TODAY...WITH DRY AIR ALF AND SFC HI PRES MOVING ACRS THE UPR LKS
THIS MRNG...EXPECT DRY WX TO PREVAIL EVEN THOUGH THERE SHOULD BE A
GOOD DEAL OF SC LINGERING NEAR LK SUP. BUT EVEN OVER THE SCNTRL
ZNS...EXTENSIVE MID/HI CLD UPSTREAM SHOULD BRING ABOUT A MOCLDY DAY.
OF MORE CONCERN IS HOW QUICKLY THE RA NOW IN THE HI PLAINS WL SPREAD
INTO THE AREA THIS AFTN AS SRN MOST OF THE LEAD SHRTWVS RIPPLES EWD
ALONG W-E H85 FNT THAT SETS UP OVER THE LOWER GRT LKS. THE 00Z NAM
HAS TRENDED TOWARD THE NON NCEP GUIDANCE...WHICH SHOWS BULK OF PCPN
REMAINING TO THE SW OF THE WI BORDER THRU 00Z. IN FACT...THE NAM IS
NOW COMPLETELY DRY THRU 00Z WITH LLVL NE FLOW ON THE SRN FLANK OF HI
CENTER MOVING ACROSS ONTARIO ADVECTING VERY DRY H85 AIR INTO THE
CWA...WITH CORE OF LOWEST H85 DEWPT OF -16C OVER THE NCNTRL AT 00Z.
NAM FCST NRN EDGE OF THE PCPN LINES UP FAIRLY WELL WITH ITS AXIS OF
SHARPEST H7-5 FGEN...WHICH SEEMS A GOOD BET. EVEN THOUGH THE 00Z GFS
SHOWS H85 DEWPTS IN THE CORE OF THE DRY AIR AS LO AS -25C...THE 00Z
GFS AND NON NCEP MODELS APPEAR TO BROAD BRUSH PCPN TOO FAR N INTO
THE DRIER LLVL AIR AND UNDER FAIRLY IMPRESSIVE UPR DVGC THAT EVEN
THE NAM SHOWS OVER THE SRN HALF OF UPR MI IN RRQ OF H3 JET MAX IN
ONTARIO. WHILE THIS UPR DVGC WL RESULT IN THICKER MID CLD...SUSPECT
THE LLVL DRY AIR WL TEND TO CAUSE THE NRN EDGE OF THE PCPN TO BE
SHARPER THAN DEPICTED BY MANY OF THE MODELS AND LIKELY REMAIN NO
FARTHER N THAN MNM COUNTY CLOSER TO THE H85 FRONT IN THE LOWER LKS.
WEAKNESS OF SHRTWVS IN THE NRN PLAINS ALSO ARGUES FOR HIER POPS TO
BE SUPPRESSED TO THE S. OPTED TO CUT PREVIOUS FCST POPS THAT WERE AS
HI AS LIKELY OVER THE FAR SCNTRL TO NO MORE THAN CHC. THE 00Z GFS
SHOWS THE AXIS OF SHARPEST H7-5 FGEN FARTHER N THAN THE NAM...AND
USED THIS AXIS FOR THE NRN EDGE OF THE CHC POPS. WITH NE FLOW OFF
THE CHILLY WATERS OF LK SUP AND THICKENING CLD COVER...EXPECT WELL
BLO NORMAL HI TEMPS. ALTHOUGH HI TEMPS WL RISE INTO THE 40S...FCST
WBZ HGTS/EVAPORATIVE COOLING INDICATE THE PCPN MAY BE MIXED WITH SN
ON ITS NRN EDGE. BUT ANY PCPN WL BE TOO LGT FOR ANY SN
ACCUMULATION...ESPECIALLY WITH THE WARM SFCS.
TONIGHT...FOCUS REMAINS ON DETERMINING QPF OVER THE FAR SCNTRL AND
THE NRN EDGE OF THE PCPN SHIELD AS SHARPER SHRTWV NOW IN THE PAC NW
DEEPENS THE TROF OVER THE UPR MS RIVER VALLEY AND INDUCES A SOMEWHAT
MORE WELL DEFINED LO PRES ON THE FNT IN THE LOWER LKS. AS THE LLVL
FLOW VEERS TO MORE E ASSOCIATED WITH THIS DVLPG LO...THE CORE OF
DRIEST AIR WL SHIFT TO THE W AS WARMER/MOISTER AIR ARRIVES FM THE
E...AND MODEL CONSENSUS SHOWS PCPN IMPACTING MAINLY THE SE HALF OF
THE CWA WITH LARGER SCALE QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET
MAX TO THE NE IN PLAY. USED THE AXIS OF SHARPEST NAM/GFS H7-5 FGEN
TO DEFINE A SHARPER NW EDGE TO THE PCPN SHIELD ACRS THE CENTRAL ZNS.
AS FAR AS QPF OVER THE SE ZNS IS CONCERNED...00Z NAM/GFS MODELS
SHOW AS MUCH AS 0.75 TO 1.00 INCH QPF AT MNM NEAR THE NRN EDGE OF
THE PCPN SHIELD EVEN THOUGH SHARPER H85-7 FGEN/H85 THERMAL GRADIENT
REMAINS TO THE S OF THAT LOCATION. SINCE DYNAMIC/EVAPORATIVE COOLING
FAVORS THE MORE AGGRESSIVE COOLING SHOWN BY THE NAM WITH NOCTURNAL
COOLING...PREFER ITS FCST H100-85 THKNS LOWERING FASTER TO SUG RA
CHANGING TO SN OVER THE S HALF OF MNM COUNTY. THIS SCENARIO IS IN
GOOD AGREEMENT WITH THE NCEP GUIDANCE...WHICH PAINTS 2 TO 4 INCHES
IN THIS AREA. SINCE MODEL QPF IS LIKELY OVERDONE TO THE N AT IMT AND
BEYOND...DID NOT EXTEND THE ADVY FARTHER TO THE N. GUIDANCE SUGS
MORE LLVL WARMING OVER THE ERN ZNS...SO DID NOT INCLUDE THAT AREA IN
THE ADVY WITH PTYPE MORE LIKELY TO STAY RA THERE LONGER. AFTER
COORDINATION WITH THE GRB OFFICE...OPTED TO ISSUE WINTER WX ADVY FOR
MNM COUNTY FOR 03Z-12Z.
FRI...EXPECT PCPN TO DIMINISH IN THE MRNG AS LO PRES SLIDES TO THE E
INTO THE LOWER GREAT LAKES AND DEERER MSTR/DYNAMICS EXIT TO THE E.
PER NCEP GUIDANCE...DID NOT FOLLOW THE SLOWER CNDN MODEL...WHICH
INDICATES HEAVIER PCPN WOULD LINGER LONGER. AS HIGH PRES BUILDS INTO
THE AREA IN THE WAKE OF THE LO PRES...EXPECT INCRSG SUNSHINE. BUT
STEADY WIND OFF THE CHILLY WATERS OF LK SUP WL CAUSE TEMPS TO RUN
BLO NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 529 AM EDT THU APR 19 2012
CANADIAN HIGH PRESSURE BUILDING SOUTH OVER THE AREA FRIDAY NIGHT
INTO SATURDAY NIGHT WILL RESULT IN GENERALLY DRY BUT COOLER WEATHER.
850MB TEMPERATURES FALLING TO AROUND -6C ON SATURDAY IN A NRLY FLOW
WILL YIELD HIGH TEMPS ONLY IN THE 40S FOR MOST AREAS...EXCEPT
POSSIBLY APPROACHING 50F IN A FEW SPOTS ALONG THE WI BDR. SHORTWAVE
APPROACHING THE AREA IN A NW FLOW ALOFT COULD BRING IN A MIX OF
LIGHT RAIN/SNOW SHOWERS OVER THE WRN COUNTIES LATE SATURDAY NIGHT
INTO SUNDAY. AGAIN NOT EXPECTING MUCH PCPN AS MOISTURE LOOKS TO
BE LIMITED AHEAD OF THE SHORTWAVE AND FORCING WILL BE GENERALLY
WEAK.
MODELS SHOW TROUGH OVER THE WRN COUNTIES DISSIPATING LATE SUNDAY AS
THE HIGH PRESSURE RIDGE BUILDS BACK OVER THE AREA FOR THE EARLY PART
OF NEXT WEEK. AIRMASS GENERALLY MODIFIES AS HIGH TEMPS REBOUND INTO
THE 50S OVER MUCH OF THE AREA BY TUESDAY. MODELS HINT AT ANOTHER
SHORTWAVE APPROACHING FROM THE WEST TUE NIGHT INTO WEDNESDAY AS IT
RIDES OVER MID-UPR LVL RDG IN PLACE. NOT CONFIDENT THIS FEATURE
WILL PRODUCE MUCH PCPN AS IT LOOKS LIKE BEST FORCING WAA/ISENTROPIC
LIFT WILL STAY WELL NORTH OF THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 123 AM EDT THU APR 19 2012
WINDS CONTINUE TO DECREASE TONIGHT AS THE SFC LOW CONTINUES TO MOVE
FURTHER AWAY. VFR/MVFR CIGS WILL CONTINUE TO SLOWLY ERODE OVERNIGHT
FROM WEST TO EAST WITH VFR CONDITIONS PREVAILING AT ALL SITES BY
15Z. VFR CONDITIONS EXPECTED AT ALL SITES AFTER SUNRISE ALTHOUGH
THERE WILL BE AN INCREASE IN MID/HIGH CLOUDS AS SYSTEM TO THE SOUTH
OF THE REGION PASSES BY LATE IN THE FORECAST. NO PRECIPITATION
EXPECTED AT THIS TIME BUT KSAW AND KIWD WILL SEE INCREASE IN CLOUD
COVER.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 529 AM EDT THU APR 19 2012
AS HI PRES BUILDS OVER LK SUP TODAY...EXPECT DIMINISHING NW WINDS
VEERING N TO NE. A LO PRES WILL TRACK THRU THE LOWER GREAT LAKES
LATE TONIGHT INTO FRI MORNING. SINCE THE SHARPER PRES GRADIENT WILL
REMAIN TO THE S...EXPECT NE WINDS NO HIGHER THAN 20 KTS OR SO OVER
THE SCENTRAL AND E. PERSISTENT HIGH PRESSURE OVER THE AREA WILL KEEP
WINDS LESS THAN 20 KTS FRI NIGHT INTO MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 AM CDT
FRIDAY FOR MIZ012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...RJT/KC
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
219 PM CDT THU APR 19 2012
.DISCUSSION...
PRIMARY WEATHER FEATURES OF CONCERN ARE THE SHORTWAVE AND
ASSOCIATED SURFACE LOW CURRENTLY MOVING BY TO OUR SOUTH... AND
ANOTHER SHORTWAVE WHICH WILL BE EMBEDDED IN NORTHWEST UPPER FLOW
THAT WILL MOVE THROUGH THE REGION ON SATURDAY. OVERALL... THE
LARGE SCALE PATTERN WILL EVOLVE FROM ITS FAIRLY ZONAL FLOW AT THE
MOMENT TO A MUCH MORE AMPLIFIED PATTERN AS WE WORK THROUGH THE
UPCOMING WEEK. THE NUMERICAL GUIDANCE IS IN GOOD AGREEMENT ON THE
INITIAL AMPLIFICATION OF THE UPPER FLOW... BUT DIVERGES QUITE A
BIT IN HOW THINGS WILL THEN EVOLVE DURING THE MIDDLE PART OF NEXT
WEEK. GENERALLY FOLLOWED A NAM/GFS BLEND THROUGH THE NEXT FEW
DAYS... THEN STEADILY WORKED WITH MORE OF AN ECMWF/GFS BLEND
BEYOND THAT WITH A BIT MORE WEIGHT ON THE ECMWF BY THE MIDDLE OF
NEXT WEEK. OVERALL... CONFIDENCE IS FAIRLY LOW IN THE DETAILS OF
THE TUESDAY THROUGH THURSDAY TIME PERIOD NEXT WEEK... SINCE MUCH
WILL DEPEND ON IF/WHEN THE RIDGE WILL BREAK DOWN. THE ECMWF
MAINTAINS THE RIDGE MUCH MORE THAN THE GFS... WHICH PUSHES AN
UPPER LOW SOUTH TOWARD THE REGION FROM CENTRAL CANADA.
SURFACE LOW CURRENTLY OVER FAR NORTHEAST KANSAS WILL CONTINUE TO
PUSH EAST-NORTHEAST THIS EVENING AS THE UPPER SHORTWAVE WORKS INTO
THE MID-MISSISSIPPI VALLEY. THE BEST ISENTROPIC LIFT AND MID-LEVEL
FRONTOGENESIS WILL BE ACROSS THE SOUTHERN PART OF OUR CWFA AND
INTO NORTHERN IOWA AND SOUTHWEST WISCONSIN. DECENT PCPN TOTALS CAN
BE EXPECTED SOUTH OF A LINE FROM MANKATO TO EAU CLAIRE AS THE
SYSTEM PUSHES THROUGH THIS AFTERNOON AND EVENING. THE BACK EDGE OF
THE PCPN MAY MIX WITH AND/OR CHANGE TO SOME SNOW THIS EVENING AS
COLDER AIR WORKS IN BEHIND THE UPPER WAVE. FORECAST SOUNDINGS FROM
THE NAM... GFS... AND RUC SUGGEST ONLY A BRIEF WINDOW OF SNOW
POTENTIAL ACROSS OUR AREA... MAINLY OVER PARTS OF WEST CENTRAL
WISCONSIN. BETTER ACCUMULATION POTENTIAL EXISTS EAST AND SOUTHEAST
OF OUR AREA... WHERE THERE LOOKS TO BE A LONGER DURATION OF A SUB-
FREEZING PROFILE... DEEP MOISTURE... AND LIFT. A WEAK RIDGE OF
HIGH PRESSURE WILL WORK ACROSS THE REGION LATE TONIGHT THROUGH
FRIDAY... WITH DRY WEATHER EXPECTED. THE RIDGE WILL STILL BE IN
PLACE ACROSS THE EASTERN FORECAST AREA FRIDAY NIGHT... WHICH COULD
LEAD TO SOME FROST/FREEZE ISSUES. INCLUDED A MENTION OF PATCHY
FROST IN THOSE AREAS FOR NOW TO ACCOUNT FOR THAT POSSIBILITY.
RETURN FLOW AND WARM ADVECTION WILL START TO ENCROACH ON THE
WESTERN PORTION OF THE AREA FRIDAY NIGHT... SO INCLUDED A CHANCE
OF SHRA OUT THERE FOR THE OVERNIGHT HOURS. THAT CHANCE FOR PCPN
THEN MIGRATES EASTWARD ACROSS THE AREA ON SATURDAY AS THE ZONE OF
ISENTROPIC LIFT WORKS ACROSS THE CWFA WITH AN EMBEDDED SHORTWAVE
IN NORTHWEST FLOW DROPPING THROUGH AT THE SAME TIME. THE MOST
PERSISTENT AND SUBSTANTIAL PCPN LOOKS LIKE IT SHOULD FOCUS MAINLY
TO OUR NORTH... BUT WOULD EXPECT MOST LOCATIONS TO SEE AT LEAST A
BRIEF WINDOW OF SOME PCPN ON SATURDAY INTO SATURDAY NIGHT. PCPN
CHANCES MAY LINGER ACROSS THE EAST ON SUNDAY ON THE BACKSIDE OF
THE UPPER TROUGH BEFORE MORE PRONOUNCED UPPER AND SURFACE RIDGING
ARE ABLE TO WORK INTO THE AREA.
FOR THE MONDAY THROUGH THURSDAY PERIOD... CONFIDENCE IS QUITE LOW
IN THE FORECAST DETAILS AS ELUDED TO EARLIER. TRIED TO SIDE A BIT
MORE WITH THE ECMWF... ALTHOUGH IT SHOULD BE NOTED THAT ITS 12Z
SOLUTION DID TREND SLIGHTLY TOWARD THE GFS IN THE IDEA OF
SQUASHING THE EAST SIDE OF THE UPPER RIDGE A BIT BY WEDNESDAY-
THURSDAY. GIVEN THE UNCERTAINTY AND SPREAD IN SOLUTIONS... WENT
WITH A BLENDED APPROACH WHICH RESULTS IN A LONGER PERIOD OF CHANCE
POPS THAN WHAT WILL LIKELY OCCUR. HOPEFULLY SUBSEQUENT FORECASTS
WILL BE ABLE TO REFINE THE MOST LIKELY LOCATIONS AND TIME PERIODS
FOR PCPN DURING THE PERIOD.
&&
.AVIATION.../18Z TAF ISSUANCE/
/ISSUED 1233 PM CDT THU APR 19 2012/
AN AREA OF RAIN SHOWERS WAS LOCATED OVER THE SOUTHERN THIRD OF
MINNESOTA...WITH A FEW EMBEDDED LIGHTNING STRIKES IN FAR NORTHERN
IOWA. THIS AREA OF SHOWERS WILL GRADUALLY SHIFT EAST NORTHEAST
THROUGHOUT THE TAF PERIOD. EXPECT CEILINGS TO LOWER TO MVFR THIS
EVENING...BEFORE LIFTING LATER TONIGHT. HIGH PRESSURE WILL SLIDE
IN FROM THE NORTH...WHICH WILL ALLOW THE EASTERLY WINDS TO
GRADUALLY SUBSIDE AND BECOME NORTHERLY TOMORROW MORNING.
KMSP...HEAVIEST PRECIP WILL TO THE SOUTH AND EAST...WITH A SHARP
CUTOFF NEAR KMSP. THEREFORE DID NOT BRING DOWN VISBYS...AND HAVE
CEILINGS AT THE HIGHER END OF MVFR. EASTERLY WINDS WILL GRADUALLY
DIMINISH AND OVERNIGHT AND BECOME NORTHERLY.
/OUTLOOK/...
FRIDAY...VFR WITH NORTHERLY WINDS 09KT.
SATURDAY...INCREASING CLOUDS...POSSIBLE MVFR AND -SHRA. WINDS
SOUTH AT 15G50KTS...BECOMING NORTHWEST AT 15G20KT.
SUNDAY...VFR WITH NORTHWESTERLY WINDS 15G25KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
/JRB
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
903 PM CDT FRI APR 20 2012
.DISCUSSION...WE ARE DEALING WITH A COMPLEX WEATHER SITUATION THIS
EVENING AS AN UPPER TROUGH DIGS ACROSS THE DEEP SOUTH. AT THE
SURFACE...A COLD FRONT NOW EXTENDS FROM NEAR TUP TO TVR TO JUST EAST
OF AEX. BEHIND THE FRONT...A COMPLEX OF SHOWERS AND SOME TSTORMS
EXTENDS ACROSS WESTERN TN...NW MS...SE AR...AND MUCH OF WESTERN AND
CENTRAL LA. JUST A FEW HOURS AGO...THERE WAS A MUCH BETTER ORGANIZED
MCS MOVING EASTWARD ACROSS THE TX/LA BORDER...HOWEVER THIS ACTIVITY
HAS RAPIDLY WEAKENED OVER THE PAST HOUR. AS THE UPPER TROUGH
CONTINUES TO DEEPEN INTO THE NORTHERN GULF...AN UPPER LOW WILL CUT
OFF AND SFC CYCLOGENESIS IS EXPECTED ENSUE OFFSHORE...SHIFTING THE
GREATER FOCUS OF CONVECTION IN THAT DIRECTION. HOWEVER...EXISTING
SHOWER AND TSTORM ACTIVITY WILL CONTINUE TO WORK ITS WAY INTO THE
AREA BEHIND THE FRONT THIS EVENING AND OVERNIGHT. THE BEST CHANCE
FOR RAIN WILL BE OVER CENTRAL AND ESPECIALLY WESTERN PORTIONS OF THE
AREA. THERE IS QUITE A BIT OF UNCERTAINTY AS TO HOW MUCH RAIN WILL
GET INTO EASTERN PORTIONS OF THE AREA. THERE IS AN INCREASING CHANCE
THAT SOME AREAS ALONG THE I-59 CORRIDOR WILL SEE LITTLE TO NO
PRECIPITATION WITH THIS SYSTEM.
HAVE UPDATED THE OVERNIGHT FORECAST TO DELAY THE ONSET OF PRECIP BY
A FEW HOURS AND TO DECREASE POPS MAINLY OVER EASTERN PORTIONS OF THE
FORECAST AREA. OTHERWISE MOS GUIDE IS PREDICTABLY DOING A POOR JOB
WITH HOURLY TEMP AND DEWPOINTS TONIGHT...WITH A FRONT IN THE AREA.
ADJUSTED GRIDS USING THE RAW NAM AND RUC OUTPUT...WHICH SEEMED TO BE
MORE REALISTIC AND PERFORMING BETTER AT THIS TIME. NO OTHER MAJOR
ADJUSTMENTS WILL BE MADE. UPDATES ARE BEING SENT AT THIS TIME. AN
UPDATED AVIATION DISCUSSION AND PERTINENT PORTIONS OF THE PREVIOUS
DISCUSSION FOLLOW BELOW. /DL/
&&
.AVIATION...CONCERNS WILL REVOLVE AROUND A COLD FRONT
THAT WILL BE MOVING ACROSS THE FORECAST AREA THE REST OF TONIGHT
THROUGH EARLY SATURDAY. CLOUDS/SHOWERS AND A FEW THUNDERSTORMS
ACCOMPANYING THE FRONT WILL BRING MVFR CONDITIONS WITH OCCASIONAL
IFR CONDITIONS IN ASSOCIATION WITH ANY STORMS. THE BEST CHANCE FOR
GETTING STORMS WILL BE AT GLH/GWO/HKS/JAN/..BUT EXPECT DRIER AIR TO
KEEP A MORE STABLE AIRMASS AS YOU GO FARTHER EAST AND NORTH THUS
LIMITING TSTM AND OVERALL RAIN POTENTIAL. EXPECT RAINFALL CHANCES TO
DECREASE RAPIDLY SATURDAY MORNING FROM WEST TO EAST...BUT A BLANKET
OF MVFR CATEGORY STRATUS CLOUDS MAY LINGER INTO THE EARLY AFTERNOON
AT MOST SITES (ASIDE FROM PERHAPS GLH). VFR CONDITIONS WILL DEVELOP
AS WE GO INTO SATURDAY EVENING...WITH VFR CONDITIONS EXPECTED TO
PREVAIL FOR SUNDAY. /BB/EC/
&&
.PREV DISCUSSION... /ISSUED AT 251 PM CDT FRI APR 20 2012/
SHORT TERM...THROUGH SUNDAY NIGHT...BEST ASCENT WILL MOVE TO THE
SOUTH AND EAST WITH THE MID/UPPER LEVEL ENERGY SATURDAY WITH
COOLER/DRIER AIR MOVING IN SATURDAY. A FEW LEFT OVER SHOWERS MAINLY
IN THE MORNING WILL GIVE WAY TO DECREASING CLOUDS...ESPECIALLY IN
THE WEST BY THE AFTERNOON. DEVELOPING SURFACE LOW PRESSURE IN THE
NORTHERN GULF WILL ALLOW PRESSURE GRADIENT OVER THE CWA TO TIGHTEN
RESULTING IN GUSTY NORTHERLY WINDS UP TO 25 KNOTS POSSIBLE AT TIMES.
GRADIENT LOOKS TO RELAX AFTER SUNSET AS THE LOW QUICKLY MOVES EAST.
SUNDAY LOOKS DRY AND COOL./GRG/
LONG TERM...MONDAY THROUGH FRIDAY...A QUIET LONG TERM PERIOD
EXPECTED WITH BELOW NORMAL TEMPERATURES SUN-TUES WITH PASSAGE OF DRY
RE-ENFORCING COLD FRONT. A WARMING TREND IS EXPECTED INTO THE LATE
WEEK WITH SLIGHT INCREASE IN RAIN CHANCES.
A DEEPLY AMPLIFIED ERN CONUS TROUGH/WRN CONUS RIDGE PATTERN WILL BE
IN PLACE MON-TUES. A STRONG RE-ENFORCING COLD FRONT WILL SWEEP
THROUGH EARLY MONDAY MORNING...PIVOTING A NORTH TO SOUTH GRADIENT OF
0-4C 850MB TEMPS ACROSS THE ARKLAMISS BY THE AFTN. DESPITE THE FULL
SUNSHINE EXPECTED...SFC TEMPS ROUGHLY 10 DEGREES BELOW AVERAGE MON
AFTN ARE PROBABLE WITH READINGS IN THE MID 60S TO NEAR 70. HAVE CUT
A COUPLE OF DEGREES FROM MEXMOS AND TRENDED CLOSER TO EC MOS OUTPUT.
THE ARKLAMISS WILL CONTINUE TO BE UNDER DRY...SUNNY...AND DEEP NW
FLOW TUES AS PATTERN SLOWLY TRANSITIONS BY MID TO LATE WEEK. JUST
HOW QUICK THE TRANSITION WILL OCCUR IS THE QUESTION. THROUGH
WED-FRI...MODELS DIVERGE WITH OPS GFS MORE PROGRESSIVE ON BUILDING
IN H5 RIDGING OVER PLAINS/SE WHILE EC IS SLOWER AND INDICATES
CONTINUED BUT FLATTER NW FLOW REGIME WED BEFORE SOME SLIGHT
RE-AMPLIFICATION OF THE ERN TROUGH THURSDAY. THE GEM/GENS AND
INDIVIDUAL MEMBERS SUGGEST A SLOWER PROGRESSION OF THE RIDGE
BUILDING THAN THE OPS GFS GIVEN POTENTIAL RIDGING STRENGTH AND
ENHANCED BLOCKING. HAVE THUS GONE WITH AN EC/GENS BLEND. EC ENSEMBLE
MEAN FURTHER SUPPORTS STRONGER BLOCKING AND SLOWER MIGRATION OF
RIDGE THROUGH THURS-FRI ACROSS CNTRL CONUS. WITH THAT STATED...SFC
DEWPOINTS SHOULD BEGIN TO RECOVER THU/FRI HAS SFC HIGH SHIFTS FROM
NRN GOM TO SUB-TROPIC ATLANTIC. BY THU...DIURNAL SHOWERS/TSTORMS
LOOK TO BE POSSIBLE AS INSTABILITY INCREASES. WILL HAVE TO KEEP AN
EYE ON ANY POSSIBLE SE DIVING COMPLEX FROM THE MID-MS VALLEY
WED-FRIDAY IF STRONGER BLOCKING OCCURS. HAVE PLACED SOME SLIGHT
CHANCE WEATHER WORDING IN FOR THURS AND FRI AFTN AS HIGH TEMPS
RECOVER INTO THE U70S/L80S. /ALLEN/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DL/BB/EC/GRG/ALLEN
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
419 PM CDT Thu Apr 19 2012
.DISCUSSION...
Short Range (Tonight through Saturday)...
Satellite imagery from this afternoon shows the nation under the
influence of a progressive pattern, though some buckling of the
flow is apparent as a trough is seen exiting the Rocky Mountains.
Closer to home, a small shortwave ejected into the Plains ahead of
the primary trough exiting the mountainous west, and helped focus the
morning low level jet across northeast Kansas and northwest
Missouri, which resulted in some morning thunderstorms. Those storms
have since dissipated, leaving our attention focused back to our
west, where a cold front is advancing east across Kansas tied to the
leading shortwave.
Currently the front is located along a line from the tip of
northwest Missouri to Wichita, with a fair amount of cumulus cloud
cover bubbling up ahead of the front. Early afternoon soundings show
little in the way of available CAPE across our section of eastern
Kansas and Missouri, as RUC based analysis indicates there is only
about 500 J/KG of SBCAPE, and given the dry layer at the 700mb level
noted off an early afternoon sounding at KMCI, there was no ability
for the model to evaluate MLCAPE. The lack of instability looks to be
from both the cloud cover in advance of the front, and due to lower
than expected dew points, which have struggled to clime beyond the
low 50s. However, with the front advancing across Kansas, frontogenic
forcing is still expected to use what little CAPE is available late
this afternoon/early this evening to generate some scattered storms
in eastern Kansas. The storms should move northeast, but the line
will struggle to fill in unless more quality moisture can quickly
advect ahead of the front. Shear parameters for this evening are
more than sufficient to generate concerns for severe weather, but
given the lack of instability, and the way surface winds veer off as
the front moves through, and it is looking increasingly difficult for
us to realize any storms that could support much more than marginal
severe weather, which would be limited to large hail and damaging
straight line winds. Heavy rain may occur with some of these storms,
but at this time the lack of quality moisture and the progressive
nature of the front should preclude any widespread flooding threat.
With the continued consensus of the various short range operational
and ensemble models, have persisted in quickly moving the storms to
the east, leaving most of the forecast area dry after 12Z Friday.
Being behind the front Friday will allow for something we have not
seen a whole lot of in the past several months, cold air advection.
The breezy north wind behind the front will actually keep afternoon
highs below normal Friday. However, this cool trend will quickly
fade as southwest winds return for Saturday bringing highs in the 60s
back.
Cutter
Medium Range (Sunday through Thursday)...
No major changes planned to going medium range forecast. Upper
ridge axis forecast to strengthen over western US during early part
of next week while area of surface high pressure builds into
forecast area. By mid-week the upper feature shifts into the
central US. This combined with increasing southerly flow as surface
high moves to the east should provide for a gradual warm up. Appears
that temperatures could approach the 80 degree mark by Wednesday and
then again on Thursday. ECMWF, GFS, and GEM models hinting at weak
mid-level shortwave topping ridge in upper Mississippi Valley in the
Wednesday/Thursday time frame. Not out of the realm of possibility
to see some scattered precipitation over northern Missouri with this
feature. However there are enough inconsistencies in the timing and
geographic placement of the QPF that dry forecast still appears to
be the best way to go at this time.
MJM
&&
.AVIATION...
For the 18Z TAFs...VFR conditions at the terminals will give way to
a scattered line of thunderstorms early this evening as storms
initiate in eastern Kansas ahead of a cold front that will sweep
through later tonight. Expectations are that the developing storms
will advance across the Kansas-Missouri border region as a broken
line before the it consolidates across central Missouri as the front
catches up. Therefore, have gone with VCTS for the evening hours, but
anticipate needing to update as storms develop and they`re specific
tracks become evident. Otherwise, winds will remain gusty through the
afternoon, before abruptly shifting to the west and then north as the
front moves through. For the post frontal environment, MVFR ceilings
are expected to prevail, though later updates or amendments will be
watching for signs that the IFR ceilings across north central Kansas
might slide across our terminals early Friday morning.
Cutter
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1235 PM CDT THU APR 19 2012
.AVIATION...18Z TAF. TRICKY TAF PERIOD WITH RESPECT TO CLOUD COVER
WITH IFR CIGS ACROSS THE DAKOTAS AND MVFR TO VFR CLOUDS ACROSS
WESTERN NEBRASKA. HAVE ATTEMPTED TO GO MIDDLE GROUND WITH MVFR
CIGS FOR THE MOST PART HOWEVER COULD SEE SOME IFR CIGS AT TIMES.
CLOUDS LOOK TO HOLD INTO THE NIGHT BEFORE THE LOWER CLOUDS
SCATTER FRIDAY MORNING...ALTHOUGH MID CLOUDS LOOK TO HOLD AT LEAST
THRU THE MORNING. WINDS WILL REMAIN NORTHERLY THROUGH THE TAF
PERIOD...WITH AN INCREASE IN WIND SPEEDS THIS AFTERNOON...WITH
WINDS DROPPING OFF OVERNIGHT AND INTO FRIDAY. RAIN SHOWERS WILL
MOVE EAST OF THE TERMINAL BY 18Z...WITH PCPN CHCS LOOKING TO
REMAIN WEST OF KGRI ON FRIDAY.
&&
.UPDATE...RAIN SHOWERS ARE GRADUALLY SHIFTING EAST INTO EASTERN
NEBRASKA EARLY THIS AFTERNOON AND COOL FRONTAL BOUNDARY HAS
ESSENTIALLY CLEARED OUR SOUTHEAST CWA. ONCE RAIN DEPARTS SC
NEBRASKA...LOOKING AT DRY CONDITIONS FOR THE MOST PART IN THIS
AREA...BUT WILL HOLD ONTO SOME LOW BUFFER POPS IN VCNTY OF FRONTAL
BOUNDARY IN OUR SE THIS AFTN.
&&
PREV DISCUSSION... /ISSUED 439 AM CDT THU APR 19 2012/
SHORT TERM...THROUGH SATURDAY NIGHT. PRIMARY CONCERN DURING THE
NEXT 72 HOURS IS COVERAGE/LIKELIHOOD OF SHOWERS AND/OR
THUNDERSTORMS TODAY INTO FRIDAY. OTHERWISE...ANTICIPATING
LEGITIMATELY DRY WEATHER HEADING INTO THE WEEKEND.
AT 08Z...OBJECTIVE SURFACE ANALYSIS REVEALED A 1002MB LOW IN FAR
SOUTHWEST KS...WITH AN INVERTED TROUGH/WARM FRONT EXTENDING
NORTHEAST FROM THE LOW UP INTO SOUTHEAST NEB. NORTH OF THIS
BOUNDARY...BREEZES WERE GENERALLY LIGHT AND EAST-NORTHEASTERLY
ACROSS THE CWA. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA CLEARLY INDICATED A RATHER LOW AMPLITUDE SHORTWAVE AXIS
CENTERED NEAR THE NE/WY/CO BORDER AREA AND STEADILY ADVANCING
EAST. AHEAD OF THIS WAVE...WARM AIR/THETA-E ADVECTION ALONG THE
NOSE OF A 55+KT 850MB LOW LEVEL JET CENTERED OVER CENTRAL
KS...ALONG WITH MID LEVEL CONVERGENCE ALONG AN ELEVATED ADVANCING
COLD FRONT...HAS PROMOTED SHOWERS/LOCALIZED THUNDERSTORMS ALL
NIGHT LONG ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...WITH THE
LEADING EDGES OF THIS ACTIVITY JUST NOW STARTING TO BRUSH THE
EXTREME NORTHERN TIP OF THE CWA IN VALLEY COUNTY. A FEW STORMS
EARLIER TONIGHT LIKELY DROPPED SOME SMALL HAIL IN WEST CENTRAL NEB
TO THE WEST OF THE CWA...BUT AT THE PRESENT TIME NO STORMS ARE ALL
THAT STRONG LET ALONE SEVERE.
STARTING OFF THIS MORNING...THE MAIN ISSUE IS CONVECTIVE
TRENDS...AND THE MAIN MESSAGE IS THAT WE STILL EXPECT SOME RAIN
ESPECIALLY IN NORTHWEST PORTIONS OF THE CWA...BUT IT WILL ARRIVE
LATER THAN EARLIER THOUGHT...MAINLY FOCUSING AFTER 12Z. FOR THE
NEXT 8 HOURS OR SO...HAVE OPTED TO FOLLOW QPF TRENDS FROM THE 06Z
HRRR AND RUC QUITE CLOSELY AS THE ALIGN CLOSEST WITH ONGOING RADAR
TRENDS. AT THE SFC...THE LOW PRESSURE CENTER OVER SOUTHWEST KS
WILL GRADUALLY MIGRATE NORTHEAST...REACHING NORTHEAST KS BY 18Z.
AS THE WAVE MOVES IN...ANTICIPATE THE LEADING EDGE OF CONVECTION
IN/NEAR THE FAR NORTHERN CWA TO MAINLY CONTINUE RIDING JUST NORTH
OF THE CWA. AS A RESULT...MUCH OF THE NORTHWEST CWA WILL HAVE TO
WAIT A FEW MORE HOURS...MAINLY AFTER SUNRISE...FOR THE TRAILING
SHOWERS/STORMS DRIVEN MAINLY BY CONVERGENCE NEAR THE 700MB FRONT
TO LIFT FROM SOUTHWEST-NORTHEAST ACROSS THE AREA. GIVEN THE TRACK
OF THE SYSTEM...HAVE POPS THROUGH THE MORNING HOURS RANGING FROM
LIKELY 60S ACROSS ROUGHLY THE NORTHWEST 1/4 OF THE CWA...TO SLIGHT
20S CLOSER TO THE STATE LINE...AND NOTHING IN THE FAR SOUTHERN ROW
OF KS COUNTIES. ALTHOUGH NOT VERY CONFIDENT IN ITS
DEVELOPMENT...COULD ALSO SEE SOME SCATTERED SHOWERS POP UP TOWARD
SUNRISE IN OR JUST OUTSIDE OF THE FAR EASTERN CWA...WITHIN THE
MAIN LOW LEVEL JET CONVERGENCE ZONE...BUT BETTER POTENTIAL WOULD
SEEM TO BE OVER THE OAX CWA. AT ANY RATE...THE RISK OF STRONG TO
SEVERE STORMS SHOULD REMAIN LOW THIS MORNING...WITH THE LATEST RUC
INDICATING PREVAILING MUCAPE VALUES OF 300 J/KG OR LESS...ALTHOUGH
STILL IN THE PRESENCE OF 40+KT OF 0-6KM BULK SHEAR. OF
COURSE...SMALL HAIL POTENTIALLY UP TO DIME SIZE IS NOT OUT OF THE
QUESTION.
TURNING TOWARD THE AFTERNOON HOURS...THE PRIMARY SURFACE COLD
FRONT SHOULD BE CLEAR OF NEARLY THE ENTIRE CWA BY 18Z...WITH
FAIRLY STOUT NORTH WINDS SUSTAINED AROUND 20 MPH WITH GUSTS TO
AROUND 30 MPH IN ITS WAKE. THIS SURFACE FRONT WILL DEFINITELY BE
THE MAIN REGIONAL FOCUS FOR LEGITIMATE STRONG TO SEVERE
CONVECTION...AS STORMS DEVELOP ALONG ALONG A LINE FROM EASTERN-
SOUTH CENTRAL KS. MEANWHILE...MUCH LOWER MLCAPE VALUES AVERAGING
AROUND 500 J/KG OR LESS WILL LINGER OVER THE CWA...WHICH COULD
CONTINUE TO GENERATE ISOLATED TO SCATTERED SHOWERS/STORMS DURING
THE AFTERNOON. NOT EXPECTING THIS AFTERNOON COVERAGE TO BE AS
GREAT AS THAT DURING THE MORNING...AND THUS HAVE POPS CAPPED AT 30
PERCENT IN FAR EASTERN/SOUTHERN ZONES...AND ACTUALLY KEEP ALL
MENTION OF PRECIP OUT OF THE NORTHWEST 1/4 OF THE CWA DURING THE
AFTERNOON. AS FOR HIGH TEMPS THIS AFTERNOON...CONFIDENCE IS FAIRLY
LOW...BUT ACTUALLY DROPPED A SOLID 3-5 DEGREES FROM PREVIOUS
FORECAST IN SOME AREAS...ESPECIALLY CENTRAL ZONES. SO MUCH WILL
DEPEND ON HOW FAST PRECIP EXITS...AND WITH CLOUD COVER LIKELY TO
HOLD FIRM...DAY SHIFT MAY END UP LOWERING HIGHS SEVERAL MORE
DEGREES IN SOME AREAS IF HOURLY GFS LAMP GUIDANCE IS TO BE
BELIEVED. FOR NOW THOUGH...WILL NOT GET OVERLY PESSIMISTIC...AND
AIM FOR A RANGE FROM UPPER 50S NORTH...60S CENTRAL AND LOW 70S FAR
SOUTH.
TONIGHT...KEPT THE 00Z-06Z EVENING PERIOD DRY...AS ANY CONVECTION
TRAILING BEHIND THE SURFACE COLD FRONT IN THE SOUTHERN CWA SHOULD
BE SOUTH OF THE AREA BY THEN...WHILE ANY UPSTREAM PRECIP REMAINS
WEST OVER THE HIGH PLAINS. HOWEVER...FOR THE LATE NIGHT
PERIOD...BROUGHT A 20-40 PERCENT CHANCE OF SHOWERS BACK INTO
WESTERN PORTIONS OF THE CWA...AS THE NEXT MID LEVEL WAVE DROPS
INTO NEB OUT OF SD...AND CONVERGENCE DEVELOPS ALONG THE EXIT
REGION OF A NARROW 110+KT 300MB MERIDIONAL JET STREAK SLIDING
EASTWARD FROM THE ROCKIES. BY THIS TIME...NOT EXPECTING THUNDER TO
BE AN ISSUE. FOR LOW TEMPS...OPTED TO STAY A SOLID 3+ DEGREES
ABOVE MET/MAV GUIDANCE WITH EXPECTATION OF FAIRLY EXTENSIVE CLOUDS
HOLDING READINGS UP MORE SO IN THE LOW 40S VERSUS UPPER 30S.
FRIDAY...THE MODEST NORTHWEST FLOW SHORTWAVE CONTINUES DROPPING
ACROSS THE CWA DURING THE MORNING...AND THUS LINGERED LOW POPS
MAINLY ACROSS THE WESTERN 1/2. KEPT THE AFTERNOON DRY HOWEVER AS
FORCING DEPARTS. AGAIN...NOT ANTICIPATING THUNDER. FOR HIGH
TEMPS...CHANGED LITTLE FROM PREVIOUS FORECAST...WITH BELOW NORMAL
TEMPS IN THE LOW 60S PREVAILING...AS STEADY NORTHERLY BREEZES
PERSIST THROUGH THE DAY. FRIDAY NIGHT...THE BEGINNING OF A PATTERN
CHANGE GETS GOING OVER THE PLAINS...AS AN EXPANSIVE MID LEVEL
RIDGE OVER THE SOUTHWEST CONUS STARTS TO BULGE EASTWARD A
BIT...STEERING THE MAIN UPPER JET AXIS FROM THE DAKOTAS INTO IA.
FRIDAY NIGHT LOW TEMPS MAY BE A BIT TRICKY...AND A NON-DIURNAL
TREND MAY EVENTUALLY NEED CONSIDERED AS SOUTHERLY RETURN FLOW
COMMENCES IN RESPONSE TO A NORTHERN PLAINS SHORTWAVE. FOR NOW
THOUGH...NUDGED UP LOWS A FEW DEGREES FROM PREVIOUS...AIMING FOR
39-41 MOST AREAS.
SATURDAY/SATURDAY NIGHT...MAINTAINED THE PREVIOUSLY DRY
FORECAST...AS MID LEVEL HEIGHTS CONTINUE A GRADUAL RISE...AS THE
RIDGE AXIS BECOMES INCREASINGLY AMPLIFIED ALONG THE ROCKY MOUNTAIN
CORRIDOR. INTERESTINGLY...A FEW MODELS SPIT OUT SOME LIGHT QPF
IN/NEAR THE WESTERN CWA DURING THIS TIME...POSSIBLY INDICATIVE OF
DRIZZLE...BUT AT THIS TIME LOW LEVEL SATURATION FOR DRIZZLE
APPEARS TO BE LACKING...AND ANY MEANINGFUL FORCING FOR RAIN SHOWERS
SHOULD REMAIN WELL EAST FROM SD INTO IA. AS FOR TEMPS...DESPITE A
WEAK COLD FRONT PASSING THROUGH ON SAT...EFFICIENT MIXING SHOULD
GIVE THINGS A BOOST...AND RAISED HIGHS A FEW DEGREES WITH LOW-MID
70S ACROSS MOST OF THE CWA. RAW NAM 2M TEMPS WOULD EVEN SUGGEST
SOME UPPER 70S POSSIBLE IN KS ZONES BUT NOT GOING THAT HIGH YET.
LONG TERM...SUNDAY THROUGH WEDNESDAY. THIS SHOULD BE A WARM AND DRY
PERIOD WITH AN UPPER LEVEL RIDGE SLOWLY TRACKING ACROSS THE PLAINS.
HIGH TEMPERATURES ARE EXPECTED TO STEADILY RISE THROUGH THE 70S ON
SUNDAY AND MONDAY...WITH 80S POSSIBLE BY TUESDAY INTO WEDNESDAY. THE
UPPER RIDGE WILL BEGIN TO BREAK DOWN AND SLIDE EAST AFTER
WEDNESDAY...WHICH MAY ALLOW FOR A RETURN OF PRECIPITATION CHANCES BY
LATE WEEK.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
640 AM CDT THU APR 19 2012
.AVIATION...12Z KGRI TAF. THE BIG QUESTION WILL CONTINUE TO CENTER
AROUND THE POSSIBLE DEVELOPMENT OF A LOW STRATUS DECK OVER THE
NEXT FEW HOURS. AURORA IS NOW INDICATING MVFR CEILINGS AND EXPECT
THAT CEILINGS WILL LOWER AT KGRI AS WELL. IT IS DIFFICULT TO
DETERMINE HOW LOW TO TAKE THE CEILINGS...BUT BELIEVE THAT MVFR
CEILINGS ARE MOST LIKELY WITH A LESSER CHANCE OF IFR. THERE WILL
ALSO BE THE CHANCE OF SHOWERS AT TIMES TODAY WITH HIGHEST CHANCES
AROUND MID MORNING. THE WIND IS ALREADY IN THE PROCESS OF SHIFTING
TO A MORE NORTHERLY DIRECTION WITH THE SFC LOW PASSING THROUGH THE
AREA. NORTHERLY WINDS WILL INCREASE BY LATER THIS MORNING AND
COULD BE A BIT ON THE GUSTY SIDE.
&&
.PREV DISCUSSION... /ISSUED 439 AM CDT THU APR 19 2012/
SHORT TERM...THROUGH SATURDAY NIGHT. PRIMARY CONCERN DURING THE
NEXT 72 HOURS IS COVERAGE/LIKELIHOOD OF SHOWERS AND/OR
THUNDERSTORMS TODAY INTO FRIDAY. OTHERWISE...ANTICIPATING
LEGITIMATELY DRY WEATHER HEADING INTO THE WEEKEND.
AT 08Z...OBJECTIVE SURFACE ANALYSIS REVEALED A 1002MB LOW IN FAR
SOUTHWEST KS...WITH AN INVERTED TROUGH/WARM FRONT EXTENDING
NORTHEAST FROM THE LOW UP INTO SOUTHEAST NEB. NORTH OF THIS
BOUNDARY...BREEZES WERE GENERALLY LIGHT AND EAST-NORTHEASTERLY
ACROSS THE CWA. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA CLEARLY INDICATED A RATHER LOW AMPLITUDE SHORTWAVE AXIS
CENTERED NEAR THE NE/WY/CO BORDER AREA AND STEADILY ADVANCING
EAST. AHEAD OF THIS WAVE...WARM AIR/THETA-E ADVECTION ALONG THE
NOSE OF A 55+KT 850MB LOW LEVEL JET CENTERED OVER CENTRAL
KS...ALONG WITH MID LEVEL CONVERGENCE ALONG AN ELEVATED ADVANCING
COLD FRONT...HAS PROMOTED SHOWERS/LOCALIZED THUNDERSTORMS ALL
NIGHT LONG ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...WITH THE
LEADING EDGES OF THIS ACTIVITY JUST NOW STARTING TO BRUSH THE
EXTREME NORTHERN TIP OF THE CWA IN VALLEY COUNTY. A FEW STORMS
EARLIER TONIGHT LIKELY DROPPED SOME SMALL HAIL IN WEST CENTRAL NEB
TO THE WEST OF THE CWA...BUT AT THE PRESENT TIME NO STORMS ARE ALL
THAT STRONG LET ALONE SEVERE.
STARTING OFF THIS MORNING...THE MAIN ISSUE IS CONVECTIVE
TRENDS...AND THE MAIN MESSAGE IS THAT WE STILL EXPECT SOME RAIN
ESPECIALLY IN NORTHWEST PORTIONS OF THE CWA...BUT IT WILL ARRIVE
LATER THAN EARLIER THOUGHT...MAINLY FOCUSING AFTER 12Z. FOR THE
NEXT 8 HOURS OR SO...HAVE OPTED TO FOLLOW QPF TRENDS FROM THE 06Z
HRRR AND RUC QUITE CLOSELY AS THE ALIGN CLOSEST WITH ONGOING RADAR
TRENDS. AT THE SFC...THE LOW PRESSURE CENTER OVER SOUTHWEST KS
WILL GRADUALLY MIGRATE NORTHEAST...REACHING NORTHEAST KS BY 18Z.
AS THE WAVE MOVES IN...ANTICIPATE THE LEADING EDGE OF CONVECTION
IN/NEAR THE FAR NORTHERN CWA TO MAINLY CONTINUE RIDING JUST NORTH
OF THE CWA. AS A RESULT...MUCH OF THE NORTHWEST CWA WILL HAVE TO
WAIT A FEW MORE HOURS...MAINLY AFTER SUNRISE...FOR THE TRAILING
SHOWERS/STORMS DRIVEN MAINLY BY CONVERGENCE NEAR THE 700MB FRONT
TO LIFT FROM SOUTHWEST-NORTHEAST ACROSS THE AREA. GIVEN THE TRACK
OF THE SYSTEM...HAVE POPS THROUGH THE MORNING HOURS RANGING FROM
LIKELY 60S ACROSS ROUGHLY THE NORTHWEST 1/4 OF THE CWA...TO SLIGHT
20S CLOSER TO THE STATE LINE...AND NOTHING IN THE FAR SOUTHERN ROW
OF KS COUNTIES. ALTHOUGH NOT VERY CONFIDENT IN ITS
DEVELOPMENT...COULD ALSO SEE SOME SCATTERED SHOWERS POP UP TOWARD
SUNRISE IN OR JUST OUTSIDE OF THE FAR EASTERN CWA...WITHIN THE
MAIN LOW LEVEL JET CONVERGENCE ZONE...BUT BETTER POTENTIAL WOULD
SEEM TO BE OVER THE OAX CWA. AT ANY RATE...THE RISK OF STRONG TO
SEVERE STORMS SHOULD REMAIN LOW THIS MORNING...WITH THE LATEST RUC
INDICATING PREVAILING MUCAPE VALUES OF 300 J/KG OR LESS...ALTHOUGH
STILL IN THE PRESENCE OF 40+KT OF 0-6KM BULK SHEAR. OF
COURSE...SMALL HAIL POTENTIALLY UP TO DIME SIZE IS NOT OUT OF THE
QUESTION.
TURNING TOWARD THE AFTERNOON HOURS...THE PRIMARY SURFACE COLD
FRONT SHOULD BE CLEAR OF NEARLY THE ENTIRE CWA BY 18Z...WITH
FAIRLY STOUT NORTH WINDS SUSTAINED AROUND 20 MPH WITH GUSTS TO
AROUND 30 MPH IN ITS WAKE. THIS SURFACE FRONT WILL DEFINITELY BE
THE MAIN REGIONAL FOCUS FOR LEGITIMATE STRONG TO SEVERE
CONVECTION...AS STORMS DEVELOP ALONG ALONG A LINE FROM EASTERN-
SOUTH CENTRAL KS. MEANWHILE...MUCH LOWER MLCAPE VALUES AVERAGING
AROUND 500 J/KG OR LESS WILL LINGER OVER THE CWA...WHICH COULD
CONTINUE TO GENERATE ISOLATED TO SCATTERED SHOWERS/STORMS DURING
THE AFTERNOON. NOT EXPECTING THIS AFTERNOON COVERAGE TO BE AS
GREAT AS THAT DURING THE MORNING...AND THUS HAVE POPS CAPPED AT 30
PERCENT IN FAR EASTERN/SOUTHERN ZONES...AND ACTUALLY KEEP ALL
MENTION OF PRECIP OUT OF THE NORTHWEST 1/4 OF THE CWA DURING THE
AFTERNOON. AS FOR HIGH TEMPS THIS AFTERNOON...CONFIDENCE IS FAIRLY
LOW...BUT ACTUALLY DROPPED A SOLID 3-5 DEGREES FROM PREVIOUS
FORECAST IN SOME AREAS...ESPECIALLY CENTRAL ZONES. SO MUCH WILL
DEPEND ON HOW FAST PRECIP EXITS...AND WITH CLOUD COVER LIKELY TO
HOLD FIRM...DAY SHIFT MAY END UP LOWERING HIGHS SEVERAL MORE
DEGREES IN SOME AREAS IF HOURLY GFS LAMP GUIDANCE IS TO BE
BELIEVED. FOR NOW THOUGH...WILL NOT GET OVERLY PESSIMISTIC...AND
AIM FOR A RANGE FROM UPPER 50S NORTH...60S CENTRAL AND LOW 70S FAR
SOUTH.
TONIGHT...KEPT THE 00Z-06Z EVENING PERIOD DRY...AS ANY CONVECTION
TRAILING BEHIND THE SURFACE COLD FRONT IN THE SOUTHERN CWA SHOULD
BE SOUTH OF THE AREA BY THEN...WHILE ANY UPSTREAM PRECIP REMAINS
WEST OVER THE HIGH PLAINS. HOWEVER...FOR THE LATE NIGHT
PERIOD...BROUGHT A 20-40 PERCENT CHANCE OF SHOWERS BACK INTO
WESTERN PORTIONS OF THE CWA...AS THE NEXT MID LEVEL WAVE DROPS
INTO NEB OUT OF SD...AND CONVERGENCE DEVELOPS ALONG THE EXIT
REGION OF A NARROW 110+KT 300MB MERIDIONAL JET STREAK SLIDING
EASTWARD FROM THE ROCKIES. BY THIS TIME...NOT EXPECTING THUNDER TO
BE AN ISSUE. FOR LOW TEMPS...OPTED TO STAY A SOLID 3+ DEGREES
ABOVE MET/MAV GUIDANCE WITH EXPECTATION OF FAIRLY EXTENSIVE CLOUDS
HOLDING READINGS UP MORE SO IN THE LOW 40S VERSUS UPPER 30S.
FRIDAY...THE MODEST NORTHWEST FLOW SHORTWAVE CONTINUES DROPPING
ACROSS THE CWA DURING THE MORNING...AND THUS LINGERED LOW POPS
MAINLY ACROSS THE WESTERN 1/2. KEPT THE AFTERNOON DRY HOWEVER AS
FORCING DEPARTS. AGAIN...NOT ANTICIPATING THUNDER. FOR HIGH
TEMPS...CHANGED LITTLE FROM PREVIOUS FORECAST...WITH BELOW NORMAL
TEMPS IN THE LOW 60S PREVAILING...AS STEADY NORTHERLY BREEZES
PERSIST THROUGH THE DAY. FRIDAY NIGHT...THE BEGINNING OF A PATTERN
CHANGE GETS GOING OVER THE PLAINS...AS AN EXPANSIVE MID LEVEL
RIDGE OVER THE SOUTHWEST CONUS STARTS TO BULGE EASTWARD A
BIT...STEERING THE MAIN UPPER JET AXIS FROM THE DAKOTAS INTO IA.
FRIDAY NIGHT LOW TEMPS MAY BE A BIT TRICKY...AND A NON-DIURNAL
TREND MAY EVENTUALLY NEED CONSIDERED AS SOUTHERLY RETURN FLOW
COMMENCES IN RESPONSE TO A NORTHERN PLAINS SHORTWAVE. FOR NOW
THOUGH...NUDGED UP LOWS A FEW DEGREES FROM PREVIOUS...AIMING FOR
39-41 MOST AREAS.
SATURDAY/SATURDAY NIGHT...MAINTAINED THE PREVIOUSLY DRY
FORECAST...AS MID LEVEL HEIGHTS CONTINUE A GRADUAL RISE...AS THE
RIDGE AXIS BECOMES INCREASINGLY AMPLIFIED ALONG THE ROCKY MOUNTAIN
CORRIDOR. INTERESTINGLY...A FEW MODELS SPIT OUT SOME LIGHT QPF
IN/NEAR THE WESTERN CWA DURING THIS TIME...POSSIBLY INDICATIVE OF
DRIZZLE...BUT AT THIS TIME LOW LEVEL SATURATION FOR DRIZZLE
APPEARS TO BE LACKING...AND ANY MEANINGFUL FORCING FOR RAIN SHOWERS
SHOULD REMAIN WELL EAST FROM SD INTO IA. AS FOR TEMPS...DESPITE A
WEAK COLD FRONT PASSING THROUGH ON SAT...EFFICIENT MIXING SHOULD
GIVE THINGS A BOOST...AND RAISED HIGHS A FEW DEGREES WITH LOW-MID
70S ACROSS MOST OF THE CWA. RAW NAM 2M TEMPS WOULD EVEN SUGGEST
SOME UPPER 70S POSSIBLE IN KS ZONES BUT NOT GOING THAT HIGH YET.
LONG TERM...SUNDAY THROUGH WEDNESDAY. THIS SHOULD BE A WARM AND DRY
PERIOD WITH AN UPPER LEVEL RIDGE SLOWLY TRACKING ACROSS THE PLAINS.
HIGH TEMPERATURES ARE EXPECTED TO STEADILY RISE THROUGH THE 70S ON
SUNDAY AND MONDAY...WITH 80S POSSIBLE BY TUESDAY INTO WEDNESDAY. THE
UPPER RIDGE WILL BEGIN TO BREAK DOWN AND SLIDE EAST AFTER
WEDNESDAY...WHICH MAY ALLOW FOR A RETURN OF PRECIPITATION CHANCES BY
LATE WEEK.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
439 AM CDT THU APR 19 2012
.SHORT TERM...THROUGH SATURDAY NIGHT. PRIMARY CONCERN DURING THE
NEXT 72 HOURS IS COVERAGE/LIKELIHOOD OF SHOWERS AND/OR
THUNDERSTORMS TODAY INTO FRIDAY. OTHERWISE...ANTICIPATING
LEGITIMATELY DRY WEATHER HEADING INTO THE WEEKEND.
AT 08Z...OBJECTIVE SURFACE ANALYSIS REVEALED A 1002MB LOW IN FAR
SOUTHWEST KS...WITH AN INVERTED TROUGH/WARM FRONT EXTENDING
NORTHEAST FROM THE LOW UP INTO SOUTHEAST NEB. NORTH OF THIS
BOUNDARY...BREEZES WERE GENERALLY LIGHT AND EAST-NORTHEASTERLY
ACROSS THE CWA. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA CLEARLY INDICATED A RATHER LOW AMPLITUDE SHORTWAVE AXIS
CENTERED NEAR THE NE/WY/CO BORDER AREA AND STEADILY ADVANCING
EAST. AHEAD OF THIS WAVE...WARM AIR/THETA-E ADVECTION ALONG THE
NOSE OF A 55+KT 850MB LOW LEVEL JET CENTERED OVER CENTRAL
KS...ALONG WITH MID LEVEL CONVERGENCE ALONG AN ELEVATED ADVANCING
COLD FRONT...HAS PROMOTED SHOWERS/LOCALIZED THUNDERSTORMS ALL
NIGHT LONG ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...WITH THE
LEADING EDGES OF THIS ACTIVITY JUST NOW STARTING TO BRUSH THE
EXTREME NORTHERN TIP OF THE CWA IN VALLEY COUNTY. A FEW STORMS
EARLIER TONIGHT LIKELY DROPPED SOME SMALL HAIL IN WEST CENTRAL NEB
TO THE WEST OF THE CWA...BUT AT THE PRESENT TIME NO STORMS ARE ALL
THAT STRONG LET ALONE SEVERE.
STARTING OFF THIS MORNING...THE MAIN ISSUE IS CONVECTIVE
TRENDS...AND THE MAIN MESSAGE IS THAT WE STILL EXPECT SOME RAIN
ESPECIALLY IN NORTHWEST PORTIONS OF THE CWA...BUT IT WILL ARRIVE
LATER THAN EARLIER THOUGHT...MAINLY FOCUSING AFTER 12Z. FOR THE
NEXT 8 HOURS OR SO...HAVE OPTED TO FOLLOW QPF TRENDS FROM THE 06Z
HRRR AND RUC QUITE CLOSELY AS THE ALIGN CLOSEST WITH ONGOING RADAR
TRENDS. AT THE SFC...THE LOW PRESSURE CENTER OVER SOUTHWEST KS
WILL GRADUALLY MIGRATE NORTHEAST...REACHING NORTHEAST KS BY 18Z.
AS THE WAVE MOVES IN...ANTICIPATE THE LEADING EDGE OF CONVECTION
IN/NEAR THE FAR NORTHERN CWA TO MAINLY CONTINUE RIDING JUST NORTH
OF THE CWA. AS A RESULT...MUCH OF THE NORTHWEST CWA WILL HAVE TO
WAIT A FEW MORE HOURS...MAINLY AFTER SUNRISE...FOR THE TRAILING
SHOWERS/STORMS DRIVEN MAINLY BY CONVERGENCE NEAR THE 700MB FRONT
TO LIFT FROM SOUTHWEST-NORTHEAST ACROSS THE AREA. GIVEN THE TRACK
OF THE SYSTEM...HAVE POPS THROUGH THE MORNING HOURS RANGING FROM
LIKELY 60S ACROSS ROUGHLY THE NORTHWEST 1/4 OF THE CWA...TO SLIGHT
20S CLOSER TO THE STATE LINE...AND NOTHING IN THE FAR SOUTHERN ROW
OF KS COUNTIES. ALTHOUGH NOT VERY CONFIDENT IN ITS
DEVELOPMENT...COULD ALSO SEE SOME SCATTERED SHOWERS POP UP TOWARD
SUNRISE IN OR JUST OUTSIDE OF THE FAR EASTERN CWA...WITHIN THE
MAIN LOW LEVEL JET CONVERGENCE ZONE...BUT BETTER POTENTIAL WOULD
SEEM TO BE OVER THE OAX CWA. AT ANY RATE...THE RISK OF STRONG TO
SEVERE STORMS SHOULD REMAIN LOW THIS MORNING...WITH THE LATEST RUC
INDICATING PREVAILING MUCAPE VALUES OF 300 J/KG OR LESS...ALTHOUGH
STILL IN THE PRESENCE OF 40+KT OF 0-6KM BULK SHEAR. OF
COURSE...SMALL HAIL POTENTIALLY UP TO DIME SIZE IS NOT OUT OF THE
QUESTION.
TURNING TOWARD THE AFTERNOON HOURS...THE PRIMARY SURFACE COLD
FRONT SHOULD BE CLEAR OF NEARLY THE ENTIRE CWA BY 18Z...WITH
FAIRLY STOUT NORTH WINDS SUSTAINED AROUND 20 MPH WITH GUSTS TO
AROUND 30 MPH IN ITS WAKE. THIS SURFACE FRONT WILL DEFINITELY BE
THE MAIN REGIONAL FOCUS FOR LEGITIMATE STRONG TO SEVERE
CONVECTION...AS STORMS DEVELOP ALONG ALONG A LINE FROM EASTERN-
SOUTH CENTRAL KS. MEANWHILE...MUCH LOWER MLCAPE VALUES AVERAGING
AROUND 500 J/KG OR LESS WILL LINGER OVER THE CWA...WHICH COULD
CONTINUE TO GENERATE ISOLATED TO SCATTERED SHOWERS/STORMS DURING
THE AFTERNOON. NOT EXPECTING THIS AFTERNOON COVERAGE TO BE AS
GREAT AS THAT DURING THE MORNING...AND THUS HAVE POPS CAPPED AT 30
PERCENT IN FAR EASTERN/SOUTHERN ZONES...AND ACTUALLY KEEP ALL
MENTION OF PRECIP OUT OF THE NORTHWEST 1/4 OF THE CWA DURING THE
AFTERNOON. AS FOR HIGH TEMPS THIS AFTERNOON...CONFIDENCE IS FAIRLY
LOW...BUT ACTUALLY DROPPED A SOLID 3-5 DEGREES FROM PREVIOUS
FORECAST IN SOME AREAS...ESPECIALLY CENTRAL ZONES. SO MUCH WILL
DEPEND ON HOW FAST PRECIP EXITS...AND WITH CLOUD COVER LIKELY TO
HOLD FIRM...DAY SHIFT MAY END UP LOWERING HIGHS SEVERAL MORE
DEGREES IN SOME AREAS IF HOURLY GFS LAMP GUIDANCE IS TO BE
BELIEVED. FOR NOW THOUGH...WILL NOT GET OVERLY PESSIMISTIC...AND
AIM FOR A RANGE FROM UPPER 50S NORTH...60S CENTRAL AND LOW 70S FAR
SOUTH.
TONIGHT...KEPT THE 00Z-06Z EVENING PERIOD DRY...AS ANY CONVECTION
TRAILING BEHIND THE SURFACE COLD FRONT IN THE SOUTHERN CWA SHOULD
BE SOUTH OF THE AREA BY THEN...WHILE ANY UPSTREAM PRECIP REMAINS
WEST OVER THE HIGH PLAINS. HOWEVER...FOR THE LATE NIGHT
PERIOD...BROUGHT A 20-40 PERCENT CHANCE OF SHOWERS BACK INTO
WESTERN PORTIONS OF THE CWA...AS THE NEXT MID LEVEL WAVE DROPS
INTO NEB OUT OF SD...AND CONVERGENCE DEVELOPS ALONG THE EXIT
REGION OF A NARROW 110+KT 300MB MERIDIONAL JET STREAK SLIDING
EASTWARD FROM THE ROCKIES. BY THIS TIME...NOT EXPECTING THUNDER TO
BE AN ISSUE. FOR LOW TEMPS...OPTED TO STAY A SOLID 3+ DEGREES
ABOVE MET/MAV GUIDANCE WITH EXPECTATION OF FAIRLY EXTENSIVE CLOUDS
HOLDING READINGS UP MORE SO IN THE LOW 40S VERSUS UPPER 30S.
FRIDAY...THE MODEST NORTHWEST FLOW SHORTWAVE CONTINUES DROPPING
ACROSS THE CWA DURING THE MORNING...AND THUS LINGERED LOW POPS
MAINLY ACROSS THE WESTERN 1/2. KEPT THE AFTERNOON DRY HOWEVER AS
FORCING DEPARTS. AGAIN...NOT ANTICIPATING THUNDER. FOR HIGH
TEMPS...CHANGED LITTLE FROM PREVIOUS FORECAST...WITH BELOW NORMAL
TEMPS IN THE LOW 60S PREVAILING...AS STEADY NORTHERLY BREEZES
PERSIST THROUGH THE DAY. FRIDAY NIGHT...THE BEGINNING OF A PATTERN
CHANGE GETS GOING OVER THE PLAINS...AS AN EXPANSIVE MID LEVEL
RIDGE OVER THE SOUTHWEST CONUS STARTS TO BULGE EASTWARD A
BIT...STEERING THE MAIN UPPER JET AXIS FROM THE DAKOTAS INTO IA.
FRIDAY NIGHT LOW TEMPS MAY BE A BIT TRICKY...AND A NON-DIURNAL
TREND MAY EVENTUALLY NEED CONSIDERED AS SOUTHERLY RETURN FLOW
COMMENCES IN RESPONSE TO A NORTHERN PLAINS SHORTWAVE. FOR NOW
THOUGH...NUDGED UP LOWS A FEW DEGREES FROM PREVIOUS...AIMING FOR
39-41 MOST AREAS.
SATURDAY/SATURDAY NIGHT...MAINTAINED THE PREVIOUSLY DRY
FORECAST...AS MID LEVEL HEIGHTS CONTINUE A GRADUAL RISE...AS THE
RIDGE AXIS BECOMES INCREASINGLY AMPLIFIED ALONG THE ROCKY MOUNTAIN
CORRIDOR. INTERESTINGLY...A FEW MODELS SPIT OUT SOME LIGHT QPF
IN/NEAR THE WESTERN CWA DURING THIS TIME...POSSIBLY INDICATIVE OF
DRIZZLE...BUT AT THIS TIME LOW LEVEL SATURATION FOR DRIZZLE
APPEARS TO BE LACKING...AND ANY MEANINGFUL FORCING FOR RAIN SHOWERS
SHOULD REMAIN WELL EAST FROM SD INTO IA. AS FOR TEMPS...DESPITE A
WEAK COLD FRONT PASSING THROUGH ON SAT...EFFICIENT MIXING SHOULD
GIVE THINGS A BOOST...AND RAISED HIGHS A FEW DEGREES WITH LOW-MID
70S ACROSS MOST OF THE CWA. RAW NAM 2M TEMPS WOULD EVEN SUGGEST
SOME UPPER 70S POSSIBLE IN KS ZONES BUT NOT GOING THAT HIGH YET.
.LONG TERM...SUNDAY THROUGH WEDNESDAY. THIS SHOULD BE A WARM AND DRY
PERIOD WITH AN UPPER LEVEL RIDGE SLOWLY TRACKING ACROSS THE PLAINS.
HIGH TEMPERATURES ARE EXPECTED TO STEADILY RISE THROUGH THE 70S ON
SUNDAY AND MONDAY...WITH 80S POSSIBLE BY TUESDAY INTO WEDNESDAY. THE
UPPER RIDGE WILL BEGIN TO BREAK DOWN AND SLIDE EAST AFTER
WEDNESDAY...WHICH MAY ALLOW FOR A RETURN OF PRECIPITATION CHANCES BY
LATE WEEK.
&&
.PREV DISCUSSION... /ISSUED 1255 AM CDT THU APR 19 2012/
AVIATION...06Z KGRI TAF. THE BIG QUESTION WILL CENTER AROUND THE
POSSIBLE DEVELOPMENT OF A LOW STRATUS DECK AS WE NEAR DAWN.
SEVERAL FORECAST MODELS INDICATE THE POSSIBILITY OF A LOW STRATUS
DECK...BUT IT IS DIFFICULT TO DETERMINE HOW LOW IT WILL GO.
BELIEVE THAT MVFR CEILINGS ARE MOST LIKELY AROUND AND SHORTLY
AFTER DAWN. HOWEVER...WILL NOT BE SURPRISED IF WE SEE A FEW
PERIODS OF IFR CEILINGS. THERE WILL ALSO BE THE CHANCE OF SHOWERS
AND THUNDERSTORMS AROUND DAWN AS THE FRONT COMES THROUGH. THE WIND
WILL THEN CHANGE TO NORTHERLY BY MID MORNING BEHIND THE FRONT AND
COULD BE A BIT ON THE GUSTY SIDE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1117 PM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT IS CROSSING THE REGION TONIGHT...BRINGING A PERIOD OF
SHOWERS...THEN COOLER TEMPERATURES FOR SATURDAY. HIGH PRESSURE ACROSS
EASTERN CANADA WILL BRING DRY BUT COOL CONDITIONS SUNDAY. THEN
STRENGTHENING LOW PRESSURE IN THE MID ATLANTIC WILL CIRCLE BACK
INTO NEW YORK MONDAY WHICH WILL RESULT IN A SOAKING RAIN AND
POSSIBLY SOME SNOW.
&&
.NEAR TERM /THROUGH SATURDAY/...
WEAK LOW PRESSURE SHIFTING EAST ACROSS LAKE ONTARIO WITH A COLD
FRONT NOW CROSSING WESTERN NEW YORK. THERE IS A CHANCE FOR A SHOWER
AHEAD OF AND ALONG THE FRONT BUT THE STEADIEST RAIN SHOULD ARRIVE
POST-FRONTAL AFTER MIDNIGHT INTO SATURDAY MORNING.
HAVE OBSERVED A FEW STRIKES OF LIGHTNING EARLIER THIS EVENING IN WEAKLY
CONVECTIVE CELLS ALONG THE LEADING EDGE OF THE FRONT. DUE TO
THIS...SLIGHT CHANCE FOR THUNDER REMAINS IN THE WEATHER GRIDS
THROUGH AROUND 05Z. THE REGIONAL RADAR MOSAIC SHOWS THE STEADIER
SHOWERS ARE BEHIND THE COLD FRONT MOVING ACROSS SOUTHERN ONTARIO AND
OHIO. THE POST FRONTAL SHOWERS ARE LIKELY THE RESULT OF LIFT ALOFT
GENERATED BY THE UPPER TROF OVER THE CENTRAL US.
THE 00Z HRRR MODEL SHOWS STEADY RAIN ARRIVING IN NIAGARA
FRONTIER/WESTERN SOUTHERN TIER AROUND 2AM...GENESEE VALLEY AROUND
4AM AND WATERTOWN SOUTH THROUGH CENTRAL NY AROUND 8AM. MOST AREAS
WILL SEE A FEW HOURS OF RAIN WITH AN AREA AVERAGE QPF OF .10 TO .25
INCHES.
LOWS WILL RANGE FROM THE 40S WEST...TO THE LOWER 50S EAST. A DECENT
SOUTHERLY FLOW EXISTS EAST AND SOUTHEAST OF LAKE ONTARIO THIS
EVENING...WITH HIGHER TERRAIN ON THE TUG HILL AND VALLEYS FAVORABLE
TO FUNNELING LIKELY TO SEE GUSTS OF 20 TO 30 MPH.
THE FRONT WILL SLOWLY EXIT TO THE EAST ON SATURDAY...WITH SHOWERS
EXPECTED TO GRADUALLY TAPER OFF. NOT TO OPTIMISTIC ABOUT A
CLEARING DURING THE DAY...GIVEN THE SLOW MOVEMENT OF THE
FRONT...HOWEVER FAR WESTERN PORTIONS MAY SEE A FEW BREAKS OF SUN
LATE SATURDAY AFTERNOON. CLOUDS WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 40S TO LOWER 50S ACROSS WESTERN NEW YORK...NOTABLY COOLER THAN
THE PAST FEW DAYS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
HIGH PRESSURE BRIEFLY NOSES SOUTHWARD FROM EASTERN ONTARIO ON
SATURDAY NIGHT WITH SKIES CLEARING FROM WEST TO EAST. COOLER AND
DRIER AIR WITH THE CLEARING SKIES WILL ALLOW TEMPS TO FALL TO THE
LOWER 30S ACROSS THE SOUTHERN TIER AND TUG HILL REGION.
THE REGION WILL SEE A PARTLY TO MOSTLY SUNNY START TO SUNDAY WITH
CHILLY MORNING TEMPS RISING TO THE MID 40S TO AROUND 50 DEGREES BY
MID AFTERNOON. THERE WILL BE AN INCREASE IN CLOUDINESS AS A STRONG
STORM SYSTEM LIFTS NORTHWARD FROM THE MID ATLANTIC.
DEEPENING LOW PRESSURE MOVES UP THE MID ATLANTIC COAST AND
RETROGRESSES TO NEW YORK STATE ON MONDAY. THIS IS WELL DEPICTED BY
GFS AND ECMWF...THE EC IS JUST A LITTLE SLOWER THAN GFS...BUT THE
RESULT IS ABOUT THE SAME.
TO PUT THIS INTO SOME PERSPECTIVE...THIS PATTERN IS ALMOST A FRAME
BY FRAME REPLAY OF AN EVENT WHICH OCCURRED ON THE 2ND AND 3RD OF
APRIL 2005. THERE WAS AN 8 INCH SNOWFALL AT KBUF WITH MORE THAN A
FOOT OF SNOW ALONG THE CHAUTAUQUA RIDGE...AND EVEN TWO FEET OF SNOW
ACROSS NORTHWESTERN PA AND NORTHEAST OHIO.
THE CURRENT GFS AND ECMWF INDICATE THE POTENTIAL FOR SIMILAR AMOUNT
OF SNOW IN VERY SIMILAR LOCATIONS. GLANCING AT A COMPARISON OF THE
2005 EVENT AND CURRENT BUFKIT SOUNDINGS...THE VERTICAL TEMP/DEWPOINT
PROFILE IS NEARLY EXACT WITH THE CURRENT DATA SHOWING EVEN MORE
MOISTURE ALOFT. THE 2005 EVENT HAD PRECIPITABLE WATER RANGING FROM
.45 INCH TO .55 INCH...THE CURRENT DATA SHOW PWS AT OR ABOVE .75
INCH. ADDITIONALLY...THE 850MB TEMPS ARE COLDER BY A DEGREE OR TWO
SOUTH OF BUFFALO TO WESTERN PENNSYLVANIA.
SPEAKING OF MOISTURE...THERE WILL BE SIGNIFICANT MOISTURE WRAPPED
ABOUT THIS STORM...QPF FOR CENTRAL NY THROUGH MONDAY EVENING WILL BE
ON THE ORDER OF 2.5 INCHES WITH 1.75 TO 2.00 INCHES ACROSS WESTERN
NY. THE TRANSITION FROM RAIN TO SNOW WILL BE SOMEWHERE BETWEEN SYR
AND ROC SOUTHWARD ALONG SENECA AND CAYUGA LAKES. THE HEAVIEST SNOW
WILL LIKELY BE CENTERED ACROSS ALLEGANY/WYOMING/CATTARAUGUS COUNTIES
WITH SNOW TOTAL EXCEEDING A FOOT...ENHANCED BY NORTHEASTERLY TO
NORTHERN WINDS AND THE UPLIFT ALONG THE WESTERN SLOPE OF THE GENESEE
VALLEY.
EXPECT RAIN ALONG THE SOUTH SHORE OF LAKE ONTARIO AND ACROSS CENTRAL
TO NORTHERN NY. THE NEAR DROUGHT CONDITIONS OF LATE WILL ABSORB THE
RAINFALL AS LONG AS IT IS NOT TOO MUCH TOO FAST...THEN THERE MAY BE
A RISK OF LOW IMPACT AND SHORT LIVED FLOODING.
IN TERMS OF HOW POTENTIALLY UNUSUAL THIS WHOLE EVENT COULD BE (ESP
THE SNOW ASPECT OF IT)...NEARLY ALL OF THE MAJOR FORECAST PARAMETERS
(H5/7 HGHTS...MSLP...H85 TEMPS...U AND V WIND COMPONENTS) ARE 4 TO 5
STANDARD DEVIATIONS FROM NORMAL. IT IS CERTAINLY SIGNIFICANT WHEN A
COUPLE FORECAST PARAMETERS ARE THAT ANOMALOUS...BUT WHEN NEARLY ALL
OF THE MAIN FACTORS ARE THIS FAR FROM NORMAL...THEN THE EVENT STARTS
TO RISE TO THAT OF A MEMORABLE OR EVEN HISTORIC STATURE. THAT BEING
SAID...THESE PARAMETERS HAVE TO COME TOGETHER IN THE PERFECT MIX AND
THAT IS STILL FAR FROM A CERTAINTY.
TEMPS SUNDAY NIGHT WILL ONCE AGAIN BE QUITE CHILLY WITH CONTINUED
NORTHERLY WINDS...MID 30S ALONG THE LAKESHORES AND THE NORTH
COUNTRY...AND UPPER 20S TO AROUND 30 DEGREES FOR THE GENESEE VALLEY
AND WESTERN SOUTHERN TIER WHERE DYNAMIC COOLING FROM THE ONSET OF
SNOW WILL LOWER TEMPS EVEN FURTHER.
THICK CLOUD COVER AND PRECIP WILL HOLD TEMPS DOWN DURING MONDAY.
EXPECT THE WARMER TEMPS IN THE UPPER 40S TO LOWER 50S ACROSS THE
NORTH COUNTRY AND CENTRAL NY CLOSER TO THE CENTER OF THE LOW
PRESSURE. COLDER TEMPS ARE EXPECTED FOR THE WEST AND ESPECIALLY
SOUTHERN COUNTIES WITH LOWER 40S ALONG THE LAKESHORES AND THE 30S
FOR THE GENESEE VALLEY AND SOUTHERN TIER...IN THE REGION OF
CONTINUED LIKELIHOOD OF SNOWFALL.
THE POPS WILL FALL FROM WEST TO EAST ON MONDAY NIGHT AS THE LOW
PRESSURE CENTER LIFT NORTHWARD INTO QUEBEC PROVINCE...BUT WILL
REMAIN AS A CHANCE OF SNOW OR A MIX OF RAIN AND SNOW. LOWS WILL BE
IN THE UPPER 20S TO LOWER 30S ACROSS WESTERN AND SOUTHERN NY WITH
LOWER TO MID 30S ELSEWHERE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
GFS AND ECMWF REMAIN IN FAIR AGREEMENT FOR MUCH OF THE REST OF THE
WEEK. WILL KEEP LOW CHANCE POPS IN FOR TUESDAY AS THE REMAINS OF THE
PREVIOUS STORM MOVE AWAY FROM THE REGION...AND CHANCE POPS THROUGH
THURSDAY AFTERNOON AS THE UPPER TROUGH OVER EASTERN CANADA STREAMS A
SERIES OF VORTICITY MAXIMA ACROSS THE GREAT LAKES REGION AND INTO
NEW YORK STATE.
TEMPS WILL MODERATE THROUGH THE REST OF THE WEEK WITH HIGHS ON
TUESDAY IN THE UPPER 30S AND LOWER 40S CLIMBING TO HIGHS IN THE MID
50S TO NEAR 60 ON FRIDAY. OVERNIGHT LOWS WILL STILL SHOW LOCAL
FLIRTATIONS WITH THE FREEZING MARK FOR THE INTERIOR COUNTIES...WITH
MID TO UPPER 30S ELSEWHERE.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
REMAINING VFR THIS EVENING. A COLD FRONT IS NOW MOVING EAST ACROSS
WESTERN NY WITH KBUF/KIAG AND KJHW ALREADY REPORTING WIND SHIFTS TO
THE NORTHWEST. THE FRONT WILL CONTINUE EAST OVERNIGHT SHIFTING EAST
OF LAKE ONTARIO AFTER MIDNIGHT. SCATTERED CONVECTIVE
SHOWERS ARE OBSERVED ALONG THE FRONT BUT MOST ACTIVITY HAS MOVED
NORTH OVER THE WEST END OF LAKE ONTARIO. THE STEADIEST SHOWERS ARE
POST FRONTAL SO RAIN IS EXPECTED TO MAINLY BE AFTER MIDNIGHT. WITH
THE ARRIVAL OF THE STEADIER RAIN SHOULD SEE A DROP IN CIGS TO
MVFR/IFR. MVFR CONDITIONS SHOULD PERSIST FOR SEVERAL HOURS BEHIND
THE FRONT...WITH A GRADUAL LIFTING LIKELY MID TO LATE MORNING ON
SATURDAY. CONCERNING KART...NAM/RUC BOTH FORECAST WINDS ALOFT TO
INCREASE THIS EVENING AND OVERNIGHT AT KART ONLY. SINCE THESE ARE NOT
EXPECTED TO MIX DOWN...HAVE ADDED LLWS AT THAT LOCATION ONLY.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...MAINLY VFR.
SUNDAY NIGHT...LOWERING TO MVFR IN LIKELY SHOWERS.
MONDAY...IFR/MVFR. RAIN OR SNOW LIKELY.
TUESDAY THROUGH THURSDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
A COLD FRONT WILL SLOWLY CROSS THE EASTERN LAKES TONIGHT. A DECENT
SOUTHERLY FLOW AHEAD OF THE FRONT HAS ALLOWED A FEW GUSTS TO 20KTS
ON EASTERN PORTIONS OF LAKE ONTARIO THIS EVENING WHICH ARE MARGINAL
SUB-SMALL CRAFT CRITERIA. WINDS WILL NOT BE STRONG BEHIND THE FRONT.
THE FRONT WILL SHIFT EAST SATURDAY MORNING WITH NO ANTICIPATED
MARINE IMPACTS EXPECTED SATURDAY AND SUNDAY.
STRONG LOW PRESSURE WILL DEVELOP IN THE MID ATLANTIC REGION SUNDAY
NIGHT...WITH AN INCREASING NE-N FLOW ON THE WATERS. THIS WILL LIKELY
RESULT IN SOME FLAGS ON THE WATERS...WITH GALES A GOOD
POSSIBILITY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...SMITH
SHORT TERM...RSH/WCH
LONG TERM...WCH
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
934 PM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT...BRINGING A PERIOD OF
SHOWERS...THEN COOLER TEMPERATURES FOR SATURDAY. HIGH PRESSURE ACROSS
EASTERN CANADA WILL BRING DRY BUT COOL CONDITIONS SUNDAY. THEN
STRENGTHENING LOW PRESSURE IN THE MID ATLANTIC WILL CIRCLE BACK
INTO NEW YORK MONDAY WHICH WILL RESULT IN A SOAKING RAIN AND
POSSIBLY SOME SNOW.
&&
.NEAR TERM /THROUGH SATURDAY/...
REMAINING MILD THIS EVENING AHEAD OF A COLD FRONT APPROACHING SLOWLY
FROM THE WEST. ORIENTED FROM JUST WEST OF BUFFALO SOUTHWEST TO ERIE
PA. IR SATELLITE SHOWS A WIDE BAND OF CLOUDS WITH THE LEADING EDGE
OVER FAR WESTERN NY EXTENDING TO THE WEST ACROSS EASTERN MICHIGAN.
THIS FRONT WILL CROSS THE FORECAST AREA THIS EVENING WITH THE
STEADIEST RAIN ARRIVING POST-FRONTAL AFTER MIDNIGHT INTO
SATURDAY MORNING.
HAVE OBSERVED A FEW STRIKES OF LIGHTNING THIS EVENING IN WEAKLY
CONVECTIVE CELLS ALONG THE LEADING EDGE OF THE FRONT. DUE TO
THIS...HAVE INTRODUCED SLIGHT CHANCE FOR THUNDER INTO THE WEATHER
GRIDS BUT KEPT TIMING FOR RAIN THE SAME. THE REGIONAL RADAR MOSAIC
SHOWS THE STEADIER SHOWERS ARE BEHIND THE COLD FRONT MOVING ACROSS
SOUTHERN ONTARIO AND OHIO. THE POST FRONTAL SHOWERS ARE LIKELY THE
RESULT OF LIFT ALOFT GENERATED BY THE UPPER TROF OVER THE CENTRAL US.
THE 22Z HRRR MODEL SHOWS STEADY RAIN ARRIVING IN NIAGARA
FRONTIER/WESTERN SOUTHERN TIER AROUND 2AM...GENESEE VALLEY AROUND
4AM AND WATERTOWN SOUTH THROUGH CENTRAL NY AROUND 7AM. MOST AREAS
WILL SEE A FEW HOURS OF RAIN WITH AN AREA AVERAGE QPF OF .10 TO .25
INCHES.
TEMPERATURES WILL BE SLOW TO DROP TONIGHT...ESPECIALLY TO THE EAST.
LOWS WILL RANGE FROM THE 40S WEST...TO THE LOWER 50S EAST. A
DECENT SOUTHERLY FLOW WILL DEVELOP EAST OF LAKE ONTARIO THIS
EVENING...WITH HIGHER TERRAIN ON THE TUG HILL AND VALLEYS FAVORABLE
TO FUNNELING LIKELY TO SEE GUSTS OF 20 TO 30 MPH.
THE FRONT WILL SLOWLY EXIT TO THE EAST ON SATURDAY...WITH SHOWERS
EXPECTED TO GRADUALLY TAPER OFF. NOT TO OPTIMISTIC ABOUT A
CLEARING DURING THE DAY...GIVEN THE SLOW MOVEMENT OF THE
FRONT...HOWEVER FAR WESTERN PORTIONS MAY SEE A FEW BREAKS OF SUN
LATE SATURDAY AFTERNOON. CLOUDS WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 40S TO LOWER 50S ACROSS WESTERN NEW YORK...NOTABLY COOLER THAN
THE PAST FEW DAYS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
HIGH PRESSURE BRIEFLY NOSES SOUTHWARD FROM EASTERN ONTARIO ON
SATURDAY NIGHT WITH SKIES CLEARING FROM WEST TO EAST. COOLER AND
DRIER AIR WITH THE CLEARING SKIES WILL ALLOW TEMPS TO FALL TO THE
LOWER 30S ACROSS THE SOUTHERN TIER AND TUG HILL REGION.
THE REGION WILL SEE A PARTLY TO MOSTLY SUNNY START TO SUNDAY WITH
CHILLY MORNING TEMPS RISING TO THE MID 40S TO AROUND 50 DEGREES BY
MID AFTERNOON. THERE WILL BE AN INCREASE IN CLOUDINESS AS A STRONG
STORM SYSTEM LIFTS NORTHWARD FROM THE MID ATLANTIC.
DEEPENING LOW PRESSURE MOVES UP THE MID ATLANTIC COAST AND
RETROGRESSES TO NEW YORK STATE ON MONDAY. THIS IS WELL DEPICTED BY
GFS AND ECMWF...THE EC IS JUST A LITTLE SLOWER THAN GFS...BUT THE
RESULT IS ABOUT THE SAME.
TO PUT THIS INTO SOME PERSPECTIVE...THIS PATTERN IS ALMOST A FRAME
BY FRAME REPLAY OF AN EVENT WHICH OCCURRED ON THE 2ND AND 3RD OF
APRIL 2005. THERE WAS AN 8 INCH SNOWFALL AT KBUF WITH MORE THAN A
FOOT OF SNOW ALONG THE CHAUTAUQUA RIDGE...AND EVEN TWO FEET OF SNOW
ACROSS NORTHWESTERN PA AND NORTHEAST OHIO.
THE CURRENT GFS AND ECMWF INDICATE THE POTENTIAL FOR SIMILAR AMOUNT
OF SNOW IN VERY SIMILAR LOCATIONS. GLANCING AT A COMPARISON OF THE
2005 EVENT AND CURRENT BUFKIT SOUNDINGS...THE VERTICAL TEMP/DEWPOINT
PROFILE IS NEARLY EXACT WITH THE CURRENT DATA SHOWING EVEN MORE
MOISTURE ALOFT. THE 2005 EVENT HAD PRECIPITABLE WATER RANGING FROM
.45 INCH TO .55 INCH...THE CURRENT DATA SHOW PWS AT OR ABOVE .75
INCH. ADDITIONALLY...THE 850MB TEMPS ARE COLDER BY A DEGREE OR TWO
SOUTH OF BUFFALO TO WESTERN PENNSYLVANIA.
SPEAKING OF MOISTURE...THERE WILL BE SIGNIFICANT MOISTURE WRAPPED
ABOUT THIS STORM...QPF FOR CENTRAL NY THROUGH MONDAY EVENING WILL BE
ON THE ORDER OF 2.5 INCHES WITH 1.75 TO 2.00 INCHES ACROSS WESTERN
NY. THE TRANSITION FROM RAIN TO SNOW WILL BE SOMEWHERE BETWEEN SYR
AND ROC SOUTHWARD ALONG SENECA AND CAYUGA LAKES. THE HEAVIEST SNOW
WILL LIKELY BE CENTERED ACROSS ALLEGANY/WYOMING/CATTARAUGUS COUNTIES
WITH SNOW TOTAL EXCEEDING A FOOT...ENHANCED BY NORTHEASTERLY TO
NORTHERN WINDS AND THE UPLIFT ALONG THE WESTERN SLOPE OF THE GENESEE
VALLEY.
EXPECT RAIN ALONG THE SOUTH SHORE OF LAKE ONTARIO AND ACROSS CENTRAL
TO NORTHERN NY. THE NEAR DROUGHT CONDITIONS OF LATE WILL ABSORB THE
RAINFALL AS LONG AS IT IS NOT TOO MUCH TOO FAST...THEN THERE MAY BE
A RISK OF LOW IMPACT AND SHORT LIVED FLOODING.
IN TERMS OF HOW POTENTIALLY UNUSUAL THIS WHOLE EVENT COULD BE (ESP
THE SNOW ASPECT OF IT)...NEARLY ALL OF THE MAJOR FORECAST PARAMETERS
(H5/7 HGHTS...MSLP...H85 TEMPS...U AND V WIND COMPONENTS) ARE 4 TO 5
STANDARD DEVIATIONS FROM NORMAL. IT IS CERTAINLY SIGNIFICANT WHEN A
COUPLE FORECAST PARAMETERS ARE THAT ANOMALOUS...BUT WHEN NEARLY ALL
OF THE MAIN FACTORS ARE THIS FAR FROM NORMAL...THEN THE EVENT STARTS
TO RISE TO THAT OF A MEMORABLE OR EVEN HISTORIC STATURE. THAT BEING
SAID...THESE PARAMETERS HAVE TO COME TOGETHER IN THE PERFECT MIX AND
THAT IS STILL FAR FROM A CERTAINTY.
TEMPS SUNDAY NIGHT WILL ONCE AGAIN BE QUITE CHILLY WITH CONTINUED
NORTHERLY WINDS...MID 30S ALONG THE LAKESHORES AND THE NORTH
COUNTRY...AND UPPER 20S TO AROUND 30 DEGREES FOR THE GENESEE VALLEY
AND WESTERN SOUTHERN TIER WHERE DYNAMIC COOLING FROM THE ONSET OF
SNOW WILL LOWER TEMPS EVEN FURTHER.
THICK CLOUD COVER AND PRECIP WILL HOLD TEMPS DOWN DURING MONDAY.
EXPECT THE WARMER TEMPS IN THE UPPER 40S TO LOWER 50S ACROSS THE
NORTH COUNTRY AND CENTRAL NY CLOSER TO THE CENTER OF THE LOW
PRESSURE. COLDER TEMPS ARE EXPECTED FOR THE WEST AND ESPECIALLY
SOUTHERN COUNTIES WITH LOWER 40S ALONG THE LAKESHORES AND THE 30S
FOR THE GENESEE VALLEY AND SOUTHERN TIER...IN THE REGION OF
CONTINUED LIKELIHOOD OF SNOWFALL.
THE POPS WILL FALL FROM WEST TO EAST ON MONDAY NIGHT AS THE LOW
PRESSURE CENTER LIFT NORTHWARD INTO QUEBEC PROVINCE...BUT WILL
REMAIN AS A CHANCE OF SNOW OR A MIX OF RAIN AND SNOW. LOWS WILL BE
IN THE UPPER 20S TO LOWER 30S ACROSS WESTERN AND SOUTHERN NY WITH
LOWER TO MID 30S ELSEWHERE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
GFS AND ECMWF REMAIN IN FAIR AGREEMENT FOR MUCH OF THE REST OF THE
WEEK. WILL KEEP LOW CHANCE POPS IN FOR TUESDAY AS THE REMAINS OF THE
PREVIOUS STORM MOVE AWAY FROM THE REGION...AND CHANCE POPS THROUGH
THURSDAY AFTERNOON AS THE UPPER TROUGH OVER EASTERN CANADA STREAMS A
SERIES OF VORTICITY MAXIMA ACROSS THE GREAT LAKES REGION AND INTO
NEW YORK STATE.
TEMPS WILL MODERATE THROUGH THE REST OF THE WEEK WITH HIGHS ON
TUESDAY IN THE UPPER 30S AND LOWER 40S CLIMBING TO HIGHS IN THE MID
50S TO NEAR 60 ON FRIDAY. OVERNIGHT LOWS WILL STILL SHOW LOCAL
FLIRTATIONS WITH THE FREEZING MARK FOR THE INTERIOR COUNTIES...WITH
MID TO UPPER 30S ELSEWHERE.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR THIS EVENING AHEAD OF A COLD FRONT APPROACHING THE REGION. THE
FRONT WILL CROSS THE WESTERN NY SITES BEFORE MIDNIGHT THEN EAST OF
LAKE ONTARIO AFTER MIDNIGHT. SCATTERED CONVECTIVE
SHOWERS ARE OBSERVED AHEAD OF THE FRONT WITH VERY ISOLATED LIGHTING
OBSERVED. LEFT TS WORDING OUT OF TAFS DUE TO VERY LIMITED ACTIVITY.
THE STEADIEST SHOWERS ARE POST FRONTAL SO RAIN IS EXPECTED TO MAINLY
BE AFTER MIDNIGHT. WITH THE ARRIVAL OF THE RAIN SHOULD SEE A DROP IN
CIGS TO MVFR/IFR. MVFR CONDITIONS SHOULD PERSIST FOR SEVERAL HOURS
BEHIND THE FRONT...WITH A GRADUAL LIFTING LIKELY MID TO LATE MORNING
ON SATURDAY. CONCERNING KART...NAM/RUC BOTH FORECAST WINDS ALOFT TO
INCREASE THIS EVENING AND OVERNIGHT AT ART ONLY. SINCE THESE ARE NOT
EXPECTED TO MIX DOWN...HAVE ADDED LLWS AT THAT LOCATION ONLY.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...MAINLY VFR.
SUNDAY NIGHT...LOWERING TO MVFR IN LIKELY SHOWERS.
MONDAY...IFR/MVFR. RAIN OR SNOW LIKELY.
TUESDAY THROUGH THURSDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
A COLD FRONT WILL SLOWLY CROSS THE EASTERN LAKES TONIGHT. A DECENT
SOUTHERLY FLOW AHEAD OF THE FRONT HAS ALLOWED A FEW GUSTS TO 20KTS
ON EASTERN PORTIONS OF LAKE ONTARIO THIS EVENING WHICH ARE MARGINAL
SUB-SMALL CRAFT CRITERIA. WINDS WILL NOT BE STRONG BEHIND THE FRONT.
THE FRONT WILL SHIFT EAST SATURDAY MORNING WITH NO ANTICIPATED
MARINE IMPACTS EXPECTED SATURDAY AND SUNDAY.
STRONG LOW PRESSURE WILL DEVELOP IN THE MID ATLANTIC REGION SUNDAY
NIGHT...WITH AN INCREASING NE-N FLOW ON THE WATERS. THIS WILL LIKELY
RESULT IN SOME FLAGS ON THE WATERS...WITH GALES A GOOD
POSSIBILITY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...SMITH
SHORT TERM...RSH/WCH
LONG TERM...WCH
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
537 PM EDT THU APR 19 2012
.SYNOPSIS...
HIGH PRESSURE RIDGING ALONG THE EASTERN SEABOARD AND LOW PRESSURE
OVER THE MIDWEST WILL BRING WARMER AIR INTO THE REGION TONIGHT AND
FRIDAY. THE WARM WEATHER WILL COME TO A QUICK END AS A COLD FRONT
CROSSES THE REGION FRIDAY NIGHT AND SATURDAY. THIS FRONT WILL ALSO
BRING RAIN SHOWERS TO MUCH OF THE REGION. THE COOL AND POTENTIALLY
SHOWERY WEATHER WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AN UPPER TROUGH DIGGING ACROSS THE UPPER PLAINS AND MIDWEST WILL
INVIGORATE A SURFACE LOW OVER MO/IA/IL TONIGHT...AND SUPPORT A WARM
FRONT ACROSS THE GREAT LAKES. THIS WARM FRONT WILL BRING A LAYER OF
MID LEVEL CLOUDINESS TO THE FORECAST AREA WHICH WILL BLANKET THE
REGION AND MAINTAIN MILDER TEMPERATURES THROUGH THE NIGHT. EXPECT
OVERNIGHT LOWS IN THE UPPER 40S TO THE LOWER 50S...SOME COOLER MID
40S FOR THE TUG HILL REGION. GUSTY SOUTHWESTERLY WINDS ACROSS METRO
BUFFALO NORTHEASTWARD TO NEAR ROCHESTER WILL DIMINISH THIS EVENING
WITH WINDS BECOMING LIGHT AND VARIABLE FOR MOST LOCATIONS.
LATE AFTERNOON SHOWERS OF SOUTHERN LOWER MICHIGAN SHOULD CONTINUE TO
LIFT TO THE NORTHEAST FOLLOWING THE 1000-500MB THICKNESS GRADIENT
AND SHOULD MISS THE FORECAST AREA AS IT MOVES INTO SOUTHERN ONTARIO.
12Z GFS AND NAM12 AS WELL AS CURRENT HRRR MODELS SUPPORT THIS
CONCEPT...SO WILL LEAVE ALL THE AREA DRY FOR THIS EVENING AND
TONIGHT.
AN INFLUX OF WARMER AIR WILL FOLLOW THE DRY PASSAGE OF THE WARM
FRONT ON FRIDAY. 850MB TEMPS AT 12 FRIDAY CLIMB TO NEAR +10C OVER
SOUTHWESTERN NY AND +8C FOR THE NORTH COUNTRY. THESE TEMPS ALOFT
ALONG WITH A DOWNSLOPING SOUTHERLY WIND WILL TRANSLATE TO AFTERNOON
TEMPERATURES IN THE LOWER TO MID 70S ACROSS THE FORECAST
AREA...UPPER 70S POSSIBLE FOR THE LOWER GENESEE VALLEY AND THE
NORTHERN FINGER LAKES TO THE LAKE ONTARIO PLAIN. ALTHOUGH THE
SURFACE TEMPS WILL WARM AND THERE WILL BE AN INCREASE IN SURFACE
DEWPOINTS...THERE WILL BE INSUFFICIENT INSTABILITY TO INVOKE
CONVECTION...THE MID LEVELS WILL BE RATHER MOIST AND SUPPORT
CLOUDINESS AND A MOIST LAPSE RATE WITH ONLY ABOUT 50-80 J/KG OF MID
LEVEL CAPE. THERE MAY BE SOME VIRGA FROM THE HIGH AND MID
CLOUDS...BUT DONT EXPECT MEASURABLE PRECIP DURING THE DAY ON FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AT THE START OF THE PERIOD FRIDAY NIGHT AND SATURDAY A MID LEVEL
TROUGH WILL ADVANCE EAST ACROSS THE GREAT LAKES WITH AN ATTENDANT
SURFACE LOW MOVING FROM NEAR TORONTO FRIDAY EVENING TO MAINE BY
SATURDAY EVENING. LARGE SCALE FORCING FOR ASCENT WILL INCREASE LATER
FRIDAY NIGHT AS MID LEVEL HEIGHT FALLS AND PVA SPREAD EAST ACROSS
THE LOWER LAKES. THE RIGHT ENTRANCE REGION OF A 100+ KNOT UPPER
LEVEL JET WILL ALSO BE IN A FAVORABLE POSITION ON THE EAST SIDE OF
THE ADVANCING TROUGH TO PROVIDE UPPER LEVEL DIVERGENCE. AT THE
SURFACE A COLD FRONT WILL SURGE EAST ACROSS THE REGION BETWEEN
06Z-12Z SATURDAY. THERE WILL BE A NARROW CORRIDOR OF DECENT MOISTURE
ALONG THE FRONT WITH PWAT INCREASING TO 1-1.25 INCHES. GIVEN THE
LAYOUT OF THE LARGE SCALE FEATURES...THE COLD FRONT MAY END UP BEING
ANABATIC IN NATURE WITH MUCH OF THE LIFT AND RAIN ALONG AND BEHIND
THE SURFACE COLD FRONT.
WITH THIS IN MIND...EXPECT JUST SCATTERED LIGHT SHOWERS FRIDAY
EVENING ACROSS WESTERN NY AND THE NORTH COUNTRY...WITH A PERIOD OF
STEADIER SHOWERS ENTERING THE REGION DURING THE WEE HOURS OF
SATURDAY MORNING. 12Z MODEL GUIDANCE CONTINUES THE TREND OF A FASTER
EXIT OF THIS SYSTEM...SO EXPECT RAIN TO END IN WESTERN NY BY EARLY
TO MID MORNING SATURDAY...WITH THE BACK EDGE REACHING THE EASTERN
LAKE ONTARIO REGION BY MIDDAY OR EARLY AFTERNOON. RAINFALL AMOUNTS
LOOK MODEST WITH THIS SYSTEM... GENERALLY A TENTH TO QUARTER INCH
WITH PERHAPS A LITTLE MORE ACROSS THE SOUTHERN TIER AND EAST OF LAKE
ONTARIO...NOT ENOUGH TO ALLEVIATE THE DRY SOIL CONDITIONS. HIGH
PRESSURE WILL BUILD INTO THE UPPER LAKES AND NORTHWEST ONTARIO
PROVINCE BY SATURDAY AFTERNOON...BUT CLOUD COVER WILL LINGER ACROSS
MUCH OF THE AREA WITH JUST A FEW SUNNY BREAKS POSSIBLE IN THE FAR
WEST LATER IN THE AFTERNOON.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE UPPER LAKES SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH A PLUME OF MOISTURE AND ASCENT
MOVING TO THE EAST COAST AND REMAINING TOO FAR EAST TO PRODUCE ANY
PRECIP BACK ACROSS OUR AREA. WE STARTED A DOWNWARD TREND IN POPS
YESTERDAY...AND GIVEN MODEL GUIDANCE IS STILL CONSISTENT ON A DRY
SUNDAY HAVE NOW REMOVED POPS ALTOGETHER. IT WILL BE COOL HOWEVER
WITH 850MB TEMPS DOWN AROUND -4C...SUPPORTING HIGHS IN THE UPPER 40S
TO LOWER 50S. NORTH-NORTHWEST FLOW CROSSING LAKE ONTARIO ALONG WITH
DAYTIME HEATING WILL LIKELY PRODUCE QUITE A BIT OF CLOUD COVER WITH
STEEP LOW LEVEL LAPSE RATES...ALTHOUGH SOME SUNNY BREAKS ARE
POSSIBLE ESPECIALLY LATER IN THE DAY ON THE LAKE PLAINS AS THE LAKES
FLIP FROM UNSTABLE TO STABLE DURING THE PEAK OF DIFFERENTIAL
HEATING. BOTH SATURDAY NIGHT AND SUNDAY NIGHT WILL BE CHILLY...BUT A
DECENT GRADIENT AND AT LEAST SOME CLOUD COVER MAY PREVENT ANY
FROST/FREEZE CONCERNS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FORECAST CONFIDENCE IS LOW FOR THE MONDAY THROUGH WEDNESDAY TIME
FRAME WITH A WIDE DISPARITY IN THE MEDIUM RANGE GUIDANCE FROM RUN TO
RUN AND BETWEEN VARIOUS MODELS. THE PAST FEW RUNS OF THE GFS...
INCLUDING THE LATEST 12Z RUN DEVELOPS A SURFACE LOW OFF THE MID
ATLANTIC COAST SUNDAY NIGHT...EVENTUALLY TRACKING INTO MAINE BY
MONDAY EVENING. THIS FARTHER EAST TRACK IS DUE TO A LATER AND LESS
COMPLETE PHASING OF SHORTWAVES OVER THE NORTHEAST QUADRANT OF THE
NATION. ON THE OTHER EXTREME...THE PAST TWO RUNS OF THE ECMWF HAVE
DEVELOPED AN EXTREMELY DEEP CUTOFF LOW OVER THE CENTRAL APPALACHIANS
SUNDAY NIGHT...WHICH THEN PIVOTS NORTH ACROSS THE LOWER LAKES ON
MONDAY. THIS FORCES THE STRONG COASTAL LOW TO TRACK INLAND ACROSS
EASTERN OR EVEN CENTRAL NY. THE CANADIAN GEM IS A COMPROMISE
SOLUTION WITH A SURFACE LOW TRACKING INLAND ACROSS CENTRAL NEW
ENGLAND. TAKING A LOOK AT THE 12Z GEFS ENSEMBLES...ABOUT HALF OF
THEM ARE MUCH FARTHER WEST THAN THE OPERATIONAL GFS...WHICH DOES
LEND SOME CREDENCE TO THE FARTHER WEST SOLUTIONS.
GIVEN THE HIGH DEGREE OF MODEL UNCERTAINTY...FOR NOW HAVE
ESSENTIALLY LEFT THE OLD FORECAST IN PLACE WITH A CHANCE OF RAIN OR
SNOW IN WESTERN NY EARLY NEXT WEEK...AND LIKELY FROM THE GENESEE
VALLEY INTO CENTRAL NY FOLLOWING AN AVERAGE TRACK OF ALL MODEL
GUIDANCE. THE ECMWF SOLUTION IS EXTREME AND NOT PARTICULARLY FAVORED
BY EAST COAST STORM CLIMATOLOGY...SO THE CHANCES OF THAT VERIFYING
ARE QUITE LOW. THAT SAID...EVEN SOME OF THE MORE CONSERVATIVE GEFS
ENSEMBLE MEMBERS WOULD PRODUCE A SIGNIFICANT LATE SEASON SNOWFALL
OVER PARTS OF THE NORTHEAST. STAY TUNED.
GIVEN THE HIGH DEGREE OF UNCERTAINTY FOR EARLY IN THE WEEK...THERE
IS ALSO LOW CONFIDENCE FOR WED-THURS AND FOR NOW WILL JUST GO WITH A
DRY FORECAST AND SLOWLY MODERATING TEMPERATURES.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
A WELL DEFINED LAKE SHADOW WITHIN 40 MILES OF LAKES ERIE AND ONTARIO
WILL KEEP SKIES NEARLY CLOUD FREE THROUGH ABOUT SUNSET FOR MOST TAF
SITES...ALTHOUGH SOME DIURNALLY BASED CU WILL KEEP AN INTERMITTENT
VFR CIG OVER THE SRN TIER.
VFR CONDITIONS WILL THEN REMAIN IN PLACE THROUGH TONIGHT...DESPITE A
WEALTH OF STRATO-CU AND ALTO-CU DEVELOPING ALONG AND NORTH OF A
STRENGTHENING THERMAL GRADIENT JUST NORTH OF LAKE ONTARIO.
ON FRIDAY...LOW PRESSURE WILL CROSS LOWER MICHIGAN AND THIS WILL
PUSH THE ABV MENTIONED CIGS FURTHER NORTH AND OUT OF THE BULK OF OUR
FORECAST AREA. IN ITS WAKE...CIRRUS AND SOME SCT ALTO-CU SHOULD
PREVAIL.
OUTLOOK...
FRIDAY NIGHT...VFR/MVFR WITH SHOWERS DEVELOPING.
SATURDAY...MVFR/IFR WITH RAIN SHOWERS LIKELY...TAPERING OFF IN THE
AFTERNOON.
SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
SOUTHWESTERLY WINDS WILL DIMINISH TONIGHT AND BECOME EASTERLY FOR
A WHILE...THEN WARMER AIR ACROSS THE LAKES LATE TONIGHT AND FRIDAY
WILL LIMIT THE WAVE FORMATION. A SURFACE LOW WILL CROSS THE LOWER
GREAT LAKES FRIDAY NIGHT DRAGGING A COLD FRONT ACROSS THE LAKES
AND BRINGING FRESH NORTHWESTERLIES BEHIND IT ON SATURDAY AND THE
COOLER AIR WILL INCREASE THE WAVES ON LAKES ERIE AND ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...RSH/WCH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
345 PM EDT THU APR 19 2012
.SYNOPSIS...
HIGH PRESSURE RIDGING ALONG THE EASTERN SEABOARD AND LOW PRESSURE
OVER THE MIDWEST WILL BRING WARMER AIR INTO THE REGION TONIGHT AND
FRIDAY. THE WARM WEATHER WILL COME TO A QUICK END AS A COLD FRONT
CROSSES THE REGION FRIDAY NIGHT AND SATURDAY. THIS FRONT WILL ALSO
BRING RAIN SHOWERS TO MUCH OF THE REGION. THE COOL AND POTENTIALLY
SHOWERY WEATHER WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AN UPPER TROUGH DIGGING ACROSS THE UPPER PLAINS AND MIDWEST WILL
INVIGORATE A SURFACE LOW OVER MO/IA/IL TONIGHT...AND SUPPORT A WARM
FRONT ACROSS THE GREAT LAKES. THIS WARM FRONT WILL BRING A LAYER OF
MID LEVEL CLOUDINESS TO THE FORECAST AREA WHICH WILL BLANKET THE
REGION AND MAINTAIN MILDER TEMPERATURES THROUGH THE NIGHT. EXPECT
OVERNIGHT LOWS IN THE UPPER 40S TO THE LOWER 50S...SOME COOLER MID
40S FOR THE TUG HILL REGION. GUSTY SOUTHWESTERLY WINDS ACROSS METRO
BUFFALO NORTHEASTWARD TO NEAR ROCHESTER WILL DIMINISH THIS EVENING
WITH WINDS BECOMING LIGHT AND VARIABLE FOR MOST LOCATIONS.
LATE AFTERNOON SHOWERS OF SOUTHERN LOWER MICHIGAN SHOULD CONTINUE TO
LIFT TO THE NORTHEAST FOLLOWING THE 1000-500MB THICKNESS GRADIENT
AND SHOULD MISS THE FORECAST AREA AS IT MOVES INTO SOUTHERN ONTARIO.
12Z GFS AND NAM12 AS WELL AS CURRENT HRRR MODELS SUPPORT THIS
CONCEPT...SO WILL LEAVE ALL THE AREA DRY FOR THIS EVENING AND
TONIGHT.
AN INFLUX OF WARMER AIR WILL FOLLOW THE DRY PASSAGE OF THE WARM
FRONT ON FRIDAY. 850MB TEMPS AT 12 FRIDAY CLIMB TO NEAR +10C OVER
SOUTHWESTERN NY AND +8C FOR THE NORTH COUNTRY. THESE TEMPS ALOFT
ALONG WITH A DOWNSLOPING SOUTHERLY WIND WILL TRANSLATE TO AFTERNOON
TEMPERATURES IN THE LOWER TO MID 70S ACROSS THE FORECAST
AREA...UPPER 70S POSSIBLE FOR THE LOWER GENESEE VALLEY AND THE
NORTHERN FINGER LAKES TO THE LAKE ONTARIO PLAIN. ALTHOUGH THE
SURFACE TEMPS WILL WARM AND THERE WILL BE AN INCREASE IN SURFACE
DEWPOINTS...THERE WILL BE INSUFFICIENT INSTABILITY TO INVOKE
CONVECTION...THE MID LEVELS WILL BE RATHER MOIST AND SUPPORT
CLOUDINESS AND A MOIST LAPSE RATE WITH ONLY ABOUT 50-80 J/KG OF MID
LEVEL CAPE. THERE MAY BE SOME VIRGA FROM THE HIGH AND MID
CLOUDS...BUT DONT EXPECT MEASURABLE PRECIP DURING THE DAY ON FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AT THE START OF THE PERIOD FRIDAY NIGHT AND SATURDAY A MID LEVEL
TROUGH WILL ADVANCE EAST ACROSS THE GREAT LAKES WITH AN ATTENDANT
SURFACE LOW MOVING FROM NEAR TORONTO FRIDAY EVENING TO MAINE BY
SATURDAY EVENING. LARGE SCALE FORCING FOR ASCENT WILL INCREASE LATER
FRIDAY NIGHT AS MID LEVEL HEIGHT FALLS AND PVA SPREAD EAST ACROSS
THE LOWER LAKES. THE RIGHT ENTRANCE REGION OF A 100+ KNOT UPPER
LEVEL JET WILL ALSO BE IN A FAVORABLE POSITION ON THE EAST SIDE OF
THE ADVANCING TROUGH TO PROVIDE UPPER LEVEL DIVERGENCE. AT THE
SURFACE A COLD FRONT WILL SURGE EAST ACROSS THE REGION BETWEEN
06Z-12Z SATURDAY. THERE WILL BE A NARROW CORRIDOR OF DECENT MOISTURE
ALONG THE FRONT WITH PWAT INCREASING TO 1-1.25 INCHES. GIVEN THE
LAYOUT OF THE LARGE SCALE FEATURES...THE COLD FRONT MAY END UP BEING
ANABATIC IN NATURE WITH MUCH OF THE LIFT AND RAIN ALONG AND BEHIND
THE SURFACE COLD FRONT.
WITH THIS IN MIND...EXPECT JUST SCATTERED LIGHT SHOWERS FRIDAY
EVENING ACROSS WESTERN NY AND THE NORTH COUNTRY...WITH A PERIOD OF
STEADIER SHOWERS ENTERING THE REGION DURING THE WEE HOURS OF
SATURDAY MORNING. 12Z MODEL GUIDANCE CONTINUES THE TREND OF A FASTER
EXIT OF THIS SYSTEM...SO EXPECT RAIN TO END IN WESTERN NY BY EARLY
TO MID MORNING SATURDAY...WITH THE BACK EDGE REACHING THE EASTERN
LAKE ONTARIO REGION BY MIDDAY OR EARLY AFTERNOON. RAINFALL AMOUNTS
LOOK MODEST WITH THIS SYSTEM... GENERALLY A TENTH TO QUARTER INCH
WITH PERHAPS A LITTLE MORE ACROSS THE SOUTHERN TIER AND EAST OF LAKE
ONTARIO...NOT ENOUGH TO ALLEVIATE THE DRY SOIL CONDITIONS. HIGH
PRESSURE WILL BUILD INTO THE UPPER LAKES AND NORTHWEST ONTARIO
PROVINCE BY SATURDAY AFTERNOON...BUT CLOUD COVER WILL LINGER ACROSS
MUCH OF THE AREA WITH JUST A FEW SUNNY BREAKS POSSIBLE IN THE FAR
WEST LATER IN THE AFTERNOON.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE UPPER LAKES SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH A PLUME OF MOISTURE AND ASCENT
MOVING TO THE EAST COAST AND REMAINING TOO FAR EAST TO PRODUCE ANY
PRECIP BACK ACROSS OUR AREA. WE STARTED A DOWNWARD TREND IN POPS
YESTERDAY...AND GIVEN MODEL GUIDANCE IS STILL CONSISTENT ON A DRY
SUNDAY HAVE NOW REMOVED POPS ALTOGETHER. IT WILL BE COOL HOWEVER
WITH 850MB TEMPS DOWN AROUND -4C...SUPPORTING HIGHS IN THE UPPER 40S
TO LOWER 50S. NORTH-NORTHWEST FLOW CROSSING LAKE ONTARIO ALONG WITH
DAYTIME HEATING WILL LIKELY PRODUCE QUITE A BIT OF CLOUD COVER WITH
STEEP LOW LEVEL LAPSE RATES...ALTHOUGH SOME SUNNY BREAKS ARE
POSSIBLE ESPECIALLY LATER IN THE DAY ON THE LAKE PLAINS AS THE LAKES
FLIP FROM UNSTABLE TO STABLE DURING THE PEAK OF DIFFERENTIAL
HEATING. BOTH SATURDAY NIGHT AND SUNDAY NIGHT WILL BE CHILLY...BUT A
DECENT GRADIENT AND AT LEAST SOME CLOUD COVER MAY PREVENT ANY
FROST/FREEZE CONCERNS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FORECAST CONFIDENCE IS LOW FOR THE MONDAY THROUGH WEDNESDAY TIME
FRAME WITH A WIDE DISPARITY IN THE MEDIUM RANGE GUIDANCE FROM RUN TO
RUN AND BETWEEN VARIOUS MODELS. THE PAST FEW RUNS OF THE GFS...
INCLUDING THE LATEST 12Z RUN DEVELOPS A SURFACE LOW OFF THE MID
ATLANTIC COAST SUNDAY NIGHT...EVENTUALLY TRACKING INTO MAINE BY
MONDAY EVENING. THIS FARTHER EAST TRACK IS DUE TO A LATER AND LESS
COMPLETE PHASING OF SHORTWAVES OVER THE NORTHEAST QUADRANT OF THE
NATION. ON THE OTHER EXTREME...THE PAST TWO RUNS OF THE ECMWF HAVE
DEVELOPED AN EXTREMELY DEEP CUTOFF LOW OVER THE CENTRAL APPALACHIANS
SUNDAY NIGHT...WHICH THEN PIVOTS NORTH ACROSS THE LOWER LAKES ON
MONDAY. THIS FORCES THE STRONG COASTAL LOW TO TRACK INLAND ACROSS
EASTERN OR EVEN CENTRAL NY. THE CANADIAN GEM IS A COMPROMISE
SOLUTION WITH A SURFACE LOW TRACKING INLAND ACROSS CENTRAL NEW
ENGLAND. TAKING A LOOK AT THE 12Z GEFS ENSEMBLES...ABOUT HALF OF
THEM ARE MUCH FARTHER WEST THAN THE OPERATIONAL GFS...WHICH DOES
LEND SOME CREDENCE TO THE FARTHER WEST SOLUTIONS.
GIVEN THE HIGH DEGREE OF MODEL UNCERTAINTY...FOR NOW HAVE
ESSENTIALLY LEFT THE OLD FORECAST IN PLACE WITH A CHANCE OF RAIN OR
SNOW IN WESTERN NY EARLY NEXT WEEK...AND LIKELY FROM THE GENESEE
VALLEY INTO CENTRAL NY FOLLOWING AN AVERAGE TRACK OF ALL MODEL
GUIDANCE. THE ECMWF SOLUTION IS EXTREME AND NOT PARTICULARLY FAVORED
BY EAST COAST STORM CLIMATOLOGY...SO THE CHANCES OF THAT VERIFYING
ARE QUITE LOW. THAT SAID...EVEN SOME OF THE MORE CONSERVATIVE GEFS
ENSEMBLE MEMBERS WOULD PRODUCE A SIGNIFICANT LATE SEASON SNOWFALL
OVER PARTS OF THE NORTHEAST. STAY TUNED.
GIVEN THE HIGH DEGREE OF UNCERTAINTY FOR EARLY IN THE WEEK...THERE
IS ALSO LOW CONFIDENCE FOR WED-THURS AND FOR NOW WILL JUST GO WITH A
DRY FORECAST AND SLOWLY MODERATING TEMPERATURES.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
WITH A DRY AIRMASS IN PLACE AND STABLE CONDITIONS IN THE LOWER
ATMOSPHERE...EXPECT VFR CONDITIONS TO PERSIST TONIGHT THROUGH AT
LEAST 18Z ON FRIDAY.
OUTLOOK...
FRIDAY...VFR/MVFR WITH A CHANCE OF SHOWERS...BECOMING LIKELY AT
NIGHT.
SATURDAY...MVFR/IFR WITH RAIN SHOWERS LIKELY...TAPERING OFF IN THE
AFTERNOON.
SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
SOUTHWESTERLY WINDS WILL DIMINISH TONIGHT AND BECOME EASTERLY FOR
A WHILE...THEN WARMER AIR ACROSS THE LAKES LATE TONIGHT AND FRIDAY
WILL LIMIT THE WAVE FORMATION. A SURFACE LOW WILL CROSS THE LOWER
GREAT LAKES FRIDAY NIGHT DRAGGING A COLD FRONT ACROSS THE LAKES
AND BRINGING FRESH NORTHWESTERLIES BEHIND IT ON SATURDAY AND THE
COOLER AIR WILL INCREASE THE WAVES ON LAKES ERIE AND ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...WCH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
652 AM EDT THU APR 19 2012
.SYNOPSIS...
A COLD FRONT WILL STALL JUST OFFSHORE TODAY...THEN WILL DISSIPATE
FRIDAY. LOW PRESSURE IS EXPECTED TO DEVELOP IN THE NORTHERN GULF OF
MEXICO SATURDAY...MOVING UP THE SOUTHEAST ATLANTIC COAST ON SUNDAY
WITH A SIGNIFICANT RAIN EVENT FOR AT LEAST THE COASTAL CAROLINAS.
HIGH PRESSURE WILL BUILD IN FROM THE WEST THROUGH THE MIDDLE OF NEXT
WEEK WITH DRY WEATHER AND BELOW-NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM THURSDAY...AN AREA OF SHOWERS IS SPREADING NORTH OUT OF
THE CHARLESTON METRO AREA...ASSOCIATED WITH A WEAK MID-LEVEL
DISTURBANCE. MODEL CONSENSUS STILL HAS NOT CONVERGED WITH HOW FAR
NORTH & EAST THESE SHOWERS WILL SPREAD TODAY...BUT GIVEN A FAIRLY
HEALTH APPEARANCE ON RADAR WE HAVE RAISED POPS 10-20 PERCENT IN THE
GEORGETOWN-MYRTLE BEACH AREA...MAINLY THIS MORNING. THERE SHOULD BE
A LULL IN PRECIPITATION COVERAGE EARLY THIS AFTERNOON. THE LATEST
FEW HRRR RUNS SHOW ADDITIONAL ISOLATED SHOWERS DEVELOPING AFTER
18-19Z ALONG THE LEADING EDGE OF A WEAK SEABREEZE...SPREADING 40 OR
MORE MILES INLAND FROM THE COAST THROUGH LATE AFTERNOON. NO
SIGNIFICANT CHANGES HAVE BEEN MADE TO TEMPERATURES OR SKY COVER
FORECASTS. PREVIOUS DISCUSSION FROM 3 AM FOLLOWS...
A SURFACE COLD FRONT HAS PUSHED OFFSHORE INTO THE ATLANTIC COASTAL
WATERS THIS MORNING. A WEAK WAVE OF LOW PRESSURE DEVELOPED AT THE
SURFACE IN RESPONSE TO THE PASSAGE OF AN UPPER LEVEL TROUGH SEVERAL
HOURS AGO...AND IT WAS THIS SURFACE WAVE THAT HELPED NUDGE THE FRONT
OFFSHORE. THE FRONT SHOULD STALL OFFSHORE BY LATE THIS MORNING WITH
LITTLE ADDITIONAL MOVEMENT EXPECTED THROUGH TONIGHT. PLENTY OF
LOW-LEVEL MOISTURE WILL REMAIN BEHIND THE FRONT TO PROVIDE CLOUDY
SKIES THIS MORNING...PERHAPS IMPROVING TO "PARTLY CLOUDY" THIS
AFTERNOON. ASSUMING THIS SKY FORECAST WORKS OUT HIGH TEMPERATURES
SHOULD REACH 72-75 TODAY...PERHAPS A FEW DEGREES COOLER AT THE
EAST-FACING BEACHES WITH AN ONSHORE FLOW.
DETERMINING WHAT OUR PRECIPITATION CHANCES ARE TODAY IS TRICKY. THE
ONLY TRACKABLE FEATURE WE CAN FIND IS A WEAK MID-LEVEL DISTURBANCE
MOVING NORTH FROM THE SAVANNAH/BEAUFORT SC REGION. THE VARIOUS
MODELS HANDLE THIS ENERGY VERY DIFFERENTLY BUT THE AVERAGE SOLUTION
SEEMS TO BRING AN INCREASE IN MID-LEVEL LIFT AND MOISTURE AS FAR
NORTH AS KINGSTREE...GEORGETOWN AND PERHAPS MYRTLE BEACH BY LATE
THIS MORNING. THIS IS WHERE WE HAVE OUR HIGHEST POPS FOR
TODAY...AROUND 40 PERCENT. ELSEWHERE A SLIGHT CHANCE (20%) OF
SHOWERS SHOULD WORK SINCE THERE WILL BE LITTLE SYNOPTIC SUPPORT FOR
PRECIPITATION BUT PLENTY OF MOISTURE TO WORK WITH SHOULD SOMETHING
BELOW THE SCALE RESOLVABLE BY SYNOPTIC MODELS MOVE THROUGH THE AREA.
FORECAST SOUNDINGS SHOW ESSENTIALLY A MOIST-ADIABATIC LAPSE RATE
FROM THE BOUNDARY LAYER UP THROUGH 300 MB THIS AFTERNOON. THIS MAKES
IT TOUGH TO GENERATE POSITIVE BUOYANCY BUT ALSO DOESN`T INHIBIT
ASCENT OF PARCELS LIFTED THROUGH OTHER MEANS: SEABREEZE CONVERGENCE,
LIFT AHEAD OF A SUBTLE UPPER DISTURBANCE, ETC...
LOW-LEVEL MOISTURE WILL LINGER INTO TONIGHT AS WELL ALTHOUGH A
STABILIZING BOUNDARY LAYER AND CONTINUED LACK OF UPPER DISTURBANCES
SHOULD KEEP PRECIP CHANCES LOW. LOOK FOR THE DEVELOPMENT OF LOW
STRATUS OR FOG LATE AS WELL AS TEMPERATURES DIP TO THE DEWPOINT.
LOWS SHOULD REACH THE UPPER 50S IN MOST AREAS AWAY FROM THE BEACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...LINGERING BOUNDARY/TROUGH ALONG THE COAST
WILL MOVE BACK NORTH AS WARM FRONT ON FRIDAY. A DEEP S-SW RETURN
FLOW WILL SET UP AS RIDGE ALOFT SHIFTS FURTHER OFF SHORE AND
TROUGH DIGS DOWN THROUGH THE MISSISSIPPI VALLEY. SHOULD TAP INTO
RICH MOISTURE FROM GULF AND ATLANTIC. MAY SEE SOME ISOLATED
CONVECTION ASSOCIATED WITH THE SEA BREEZE AND THIS BOUNDARY AS IT
MOVES NORTH BUT WITHOUT MUCH IN THE WAY OF UPPER LEVEL
SUPPORT...NOT COUNTING ON MUCH.
THE GRADIENT TIGHTENS HEADING INTO SATURDAY AS A COLD FRONT
APPROACHES FROM THE NORTHWEST WHILE LOW PRESSURE SYSTEM TRACKS
ACROSS THE GULF COAST. H5 LOW CUTS OFF AND DEEPENS OVER THE GULF AND
THEN TRACKS EAST AND OPENS UP ROTATING AROUND A LONGER WAVE TROUGH
SHIFTING EAST TOWARD THE COAST THROUGH SUNDAY. THE ASSOCIATED SFC
LOW WILL TRACK OVER FLORIDA ON SUNDAY AND THEN EAST INTO THE
ATLANTIC BY MONDAY MORNING AS COLD FRONT DRIVES FARTHER SOUTH. SHOULD
SEE BEST CHC OF SHWRS/TSTMS IN WARM MOIST UNSTABLE AIR AHEAD OF COLD
FRONT AS IT APPROACHES LATE SATURDAY. IF THIS LOW REMAINS ON THIS
SOUTHERN TRACK AS GFS DEPICTS IN LATEST MODEL RUN...THE BEST PCP MAY
REMAIN OFF SHORE ON SUNDAY WITH COLD FRONT ALREADY SOUTH OF AREA.
THIS WILL LEAVE BEST CHC OF PCP ALONG THE COAST AND OFF SHORE. PCP
WATER VALUES AHEAD OF COLD FRONT REACH UP NEAR 1.4 INCHES BUT THE
REAL MOISTURE RICH AIR WITH PCP WATER VALUES UP NEAR 1.8 INCHES MAY
REMAIN JUST OFF SHORE.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...BY SUNDAY AFTERNOON WINDS VEER AROUND TO
THE NW AS COLD FRONT MOVES SOUTH AND LOW SHIFTS FARTHER EAST. PCP
WATER VALUES DROP BELOW AN INCH BY LATE SUNDAY AS PLENTY OF COOL
AND DRY AIR MAKES ITS WAY INTO AREA SUN NIGHT INTO MON. HIGH
PRESSURE WILL BUILD INTO AREA BEHIND COLD FRONT MON THROUGH TUES.
A DEEP NW FLOW WILL CONTINUE ON BACK END OF DEEP MID TO UPPER
TROUGH AS IT SLOWLY SHIFTS OFF SHORE THROUGH WEDNESDAY. MAY SEE
SOME CLOUDS DEVELOP AS VORT MAX ROTATES AROUND MID TO UPPER TROUGH
AS IT SHIFTS OFF SHORE BUT OVERALL EXPECT COOL AND DRY WEATHER MON
THROUGH WED. GUSTY NORTHWEST WINDS ON BACK END OF SYSTEM ON MONDAY
WILL WEAKEN AS LOW LIFTS OFF TO THE NORTHEAST TUES INTO WED. A
WARMER RETURN FLOW WILL SET UP MID WEEK AS HIGH SHIFTS OFF SHORE.
TEMPS ON SUNDAY WILL BEGIN TO DROP AS COLD FRONT MAKES ITS WAY
THROUGH. SHOULD SEE TEMPS UP AROUND 70 ON SUNDAY BUT BY MONDAY CAA
WILL BE IN FULL FORCE WITH GUSTY NW WINDS KEEPING TEMPS IN THE MID
60S MOST PLACES. 850 TEMPS DROP OUT FROM UP AROUND 11C SUN MORNING
DOWN TO AROUND 2 C BY MON AFTN WITH LITTLE REBOUND UNTIL RETURN
FLOW SETS UP WED AFTN. AS GRADIENT WEAKENS WINDS WILL BECOME
LIGHTER AND EXPECT BETTER RADIATIONAL COOLING MON AND TUES NIGHT.
WITH PLENTY OF DRY AIR IN PLACE EXPECT DECENT DIURNAL SWINGS IN
TEMPS MON THROUGH WED. HIGHS SHOULD JUST REACH INTO THE 70S TUES
AND SLIGHTLY WARMER ON WED BUT DAYS WILL START OUT COOL WITH
OVERNIGHT LOWS BETWEEN 40 AND 45 MOST PLACES.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...CONFIDENCE IS MODERATE TO HIGH THAT IFR/LIFR/VLIFR
CONDITIONS WILL IMPROVE TO MVFR AT FLO/LBT/ILM AS INDICATED IN TAFS.
CONFIDENCE OF IMPROVEMENT IS LOWER AT CRE/MYR DUE TO SHOWERS
CURRENTLY MOVING ACROSS THOSE TERMINALS WHICH COULD CAUSE
IMPROVEMENT EARLIER THAN INDICATED. MVFR FLIGHT CONDITIONS CAN BE
EXPECTED INTO THE AFTERNOON HOURS WITH IMPROVEMENT TO VFR LATE. THE
BEST SHOWER AND THUNDERSTORM POTENTIAL WILL BE AT THE CRE/MYR/FLO
TERMINALS DURING THE AFTERNOON. SINCE THUNDERSTORM COVERAGE IS
EXPECTED TO BE LOW WILL NOT MENTION IN TAFS. NORTHERLY WINDS THIS
MORNING WILL BECOME EAST TO SOUTHEAST THIS AFTERNOON.
THIS EVENING WINDS WILL BECOME LIGHT NORTHEAST TO EAST. CONFIDENCE
IS MODERATE TO HIGH IFR/LIFR CONDITIONS WILL OCCUR MAINLY AFTER
MIDNIGHT.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH ISOLATED SHOWERS FRIDAY.
INTERMITTENT MVFR/POSSIBLE IFR CONDITIONS WITH SCATTERED SHOWERS
SATURDAY. NUMEROUS SHOWERS/TEMPO IFR POSSIBLE SUNDAY...MAINLY NEAR
THE COAST. VFR MONDAY WITH ISOLATED SHOWERS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM THURSDAY...NO SIGNIFICANT CHANGES WITH THIS EARLY
MORNING UPDATE. PREVIOUS DISCUSSION FROM 3 AM FOLLOWS...
A WEAK COLD FRONT WILL DRIFT A LITTLE FARTHER OFFSHORE THIS
MORNING...THEN SHOULD STALL FROM ABOUT 20 MILES EAST OF CAPE FEAR TO
50 MILES EAST OF MYRTLE BEACH. THERE IS A VERY WEAK PRESSURE
GRADIENT SURROUNDING THIS FRONT SO WE ANTICIPATE LIGHT WIND SPEEDS
THROUGH TONIGHT REGARDLESS OF DIRECTION. A MAINLY NORTH WIND THIS
MORNING SHOULD VEER MORE EASTERLY THIS AFTERNOON WITH A WEAK
SEABREEZE DEVELOPING...THEN BACK TO THE NORTHEAST TONIGHT. SCATTERED
SHOWERS AND PERHAPS AN ISOLATED T-STORM ARE POSSIBLE WITH THE FRONT
IN THE VICINITY...BUT THERE IS ONLY ONE WEAK MID-LEVEL DISTURBANCE
THAT MIGHT HELP FOCUS ACTIVITY IN THE GEORGETOWN AND MYRTLE BEACH
VICINITY LATE THIS MORNING.
BUOY OBSERVATIONS SHOW SURPRISINGLY LARGE SEAS GIVEN THE WEAK WINDS
OBSERVED. SPECTRAL WAVE PLOTS FROM FRYING PAN SHOALS REVEAL
VIRTUALLY ALL THE WAVE ENERGY IS DUE TO A 15-SECOND SWELL THAT HAS
ARRIVED SEVERAL HOURS SOONER THAN ANY OF THE WAVE MODELS INDICATED.
FOR THE WATERS EAST OF CAPE FEAR SEAS COULD BUILD TO 4 FEET LATER
TODAY...WHILE ACROSS THE SC COASTAL WATERS SEAS COULD BUILD TO 3
FEET IN THE LONG-PERIOD SWELLS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...LINGERING FRONT/TROUGH LIFTS BACK NORTH
AS A WARM FRONT EARLY FRIDAY...TURNING WINDS TO THE SOUTH AND
INCREASING TO AROUND 10 KTS BY LATE FRIDAY. LONG PERIOD SWELL
DECAYS THROUGH FRIDAY...BUT INCREASING SOUTHERLY WIND WAVES KEEP
OVERALL WAVE HEIGHTS AT 2-4 FT. WINDS WILL INCREASE FURTHER ON
SATURDAY UP TO 15 TO 20 KTS AS GRADIENT TIGHTENS AS COLD FRONT
APPROACHES FROM THE NORTHWEST AND LOW DEEPENS OVER THE GULF COAST.
THIS WILL PUSH SEAS UP NEAR SCA CONDITIONS BY SAT NIGHT. THE GFS
HAS BACKED OFF ON THE SEAS A BIT AS LATEST RUN KEEPS LOW RIDING BY
FARTHER SOUTH WITH A NORTHERLY FLOW SETTING UP ON BACK END BY SUN
AFTN. THEREFORE SEAS MAY PEAK UP AROUND 6 TO 7 FT RATHER THAN THE
11 FT PROJECTED IN EARLY RUNS. THE STRENGTH AND DIRECTION OF WINDS
AND BUILD UP OF SEAS WILL BE HIGHLY DEPENDENT ON THE TRACK AND
STRENGTH OF THIS LOW AND THEREFORE MAY CHANGE AGAIN.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...WINDS WILL VEER AROUND TO THE W-NW SUN
INTO MONDAY AS LOW LIFTS OFF TO THE NORTHEAST DRAGGING A COLD
FRONT FARTHER SOUTH. SEAS WILL DIMINISH BUT EXPECT A DECENT SURGE
BEHIND FRONT KEEPING SEAS UP NEAR SCA CONDITIONS THROUGH MONDAY. THE
OFF SHORE WINDS OUT OF THE W-NW BEHIND COLD FRONT WILL VEER TO THE
NORTH AND ALLOW NEAR SHORE SEAS TO DROP BUT OVERALL WILL MAINTAIN
SEAS UP NEAR 3 TO 5 FT THROUGH MON AFTN. GRADIENT WILL WEAKEN AS
LOW LIFTS OFF MOVING FARTHER AWAY AND HIGH PRESSURE BUILDS IN
THROUGH TUESDAY. NORTHERLY WINDS WILL DIMINISH TO 10 TO 15 KTS
LATE MON INTO EARLY TUES AND SEAS WILL DROP TO 2 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
342 AM EDT THU APR 19 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SLOWLY SOUTHEAST REACHING JUST OFF
THE COAST THIS MORNING BEFORE STALLING. THIS FRONT WILL MOVE BACK
NORTH AS A WARM FRONT ON FRIDAY. AN AREA OF LOW PRESSURE WILL
DEVELOP OVER THE GULF AND TRACK EAST INTO THE ATLANTIC DRAGGING A
COLD FRONT ACROSS THE AREA ON SUNDAY. COOL AND DRY HIGH PRESSURE
WILL BUILD IN MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM THURSDAY...A SURFACE COLD FRONT HAS PUSHED OFFSHORE
INTO THE ATLANTIC COASTAL WATERS THIS MORNING. A WEAK WAVE OF LOW
PRESSURE DEVELOPED AT THE SURFACE IN RESPONSE TO THE PASSAGE OF AN
UPPER LEVEL TROUGH SEVERAL HOURS AGO...AND IT WAS THIS SURFACE WAVE
THAT HELPED NUDGE THE FRONT OFFSHORE. THE FRONT SHOULD STALL
OFFSHORE BY LATE THIS MORNING WITH LITTLE ADDITIONAL MOVEMENT
EXPECTED THROUGH TONIGHT. PLENTY OF LOW-LEVEL MOISTURE WILL REMAIN
BEHIND THE FRONT TO PROVIDE CLOUDY SKIES THIS MORNING...PERHAPS
IMPROVING TO "PARTLY CLOUDY" THIS AFTERNOON. ASSUMING THIS SKY
FORECAST WORKS OUT HIGH TEMPERATURES SHOULD REACH 72-75
TODAY...PERHAPS A FEW DEGREES COOLER AT THE EAST-FACING BEACHES WITH
AN ONSHORE FLOW.
DETERMINING WHAT OUR PRECIPITATION CHANCES ARE TODAY IS TRICKY. THE
ONLY TRACKABLE FEATURE WE CAN FIND IS A WEAK MID-LEVEL DISTURBANCE
MOVING NORTH FROM THE SAVANNAH/BEAUFORT SC REGION. THE VARIOUS
MODELS HANDLE THIS ENERGY VERY DIFFERENTLY BUT THE AVERAGE SOLUTION
SEEMS TO BRING AN INCREASE IN MID-LEVEL LIFT AND MOISTURE AS FAR
NORTH AS KINGSTREE...GEORGETOWN AND PERHAPS MYRTLE BEACH BY LATE
THIS MORNING. THIS IS WHERE WE HAVE OUR HIGHEST POPS FOR
TODAY...AROUND 40 PERCENT. ELSEWHERE A SLIGHT CHANCE (20%) OF
SHOWERS SHOULD WORK SINCE THERE WILL BE LITTLE SYNOPTIC SUPPORT FOR
PRECIPITATION BUT PLENTY OF MOISTURE TO WORK WITH SHOULD SOMETHING
BELOW THE SCALE RESOLVABLE BY SYNOPTIC MODELS MOVE THROUGH THE AREA.
FORECAST SOUNDINGS SHOW ESSENTIALLY A MOIST-ADIABATIC LAPSE RATE
FROM THE BOUNDARY LAYER UP THROUGH 300 MB THIS AFTERNOON. THIS MAKES
IT TOUGH TO GENERATE POSITIVE BUOYANCY BUT ALSO DOESN`T INHIBIT
ASCENT OF PARCELS LIFTED THROUGH OTHER MEANS: SEABREEZE CONVERGENCE,
LIFT AHEAD OF A SUBTLE UPPER DISTURBANCE, ETC...
LOW-LEVEL MOISTURE WILL LINGER INTO TONIGHT AS WELL ALTHOUGH A
STABILIZING BOUNDARY LAYER AND CONTINUED LACK OF UPPER DISTURBANCES
SHOULD KEEP PRECIP CHANCES LOW. LOOK FOR THE DEVELOPMENT OF LOW
STRATUS OR FOG LATE AS WELL AS TEMPERATURES DIP TO THE DEWPOINT.
LOWS SHOULD REACH THE UPPER 50S IN MOST AREAS AWAY FROM THE BEACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...LINGERING BOUNDARY/TROUGH ALONG THE COAST
WILL MOVE BACK NORTH AS WARM FRONT ON FRIDAY. A DEEP S-SW RETURN
FLOW WILL SET UP AS RIDGE ALOFT SHIFTS FURTHER OFF SHORE AND
TROUGH DIGS DOWN THROUGH THE MISSISSIPPI VALLEY. SHOULD TAP INTO
RICH MOISTURE FROM GULF AND ATLANTIC. MAY SEE SOME ISOLATED
CONVECTION ASSOCIATED WITH THE SEA BREEZE AND THIS BOUNDARY AS IT
MOVES NORTH BUT WITHOUT MUCH IN THE WAY OF UPPER LEVEL
SUPPORT...NOT COUNTING ON MUCH.
THE GRADIENT TIGHTENS HEADING INTO SATURDAY AS A COLD FRONT APPROACHES
FROM THE NORTHWEST WHILE LOW PRESSURE SYSTEM TRACKS ACROSS THE
GULF COAST. H5 LOW CUTS OFF AND DEEPENS OVER THE GULF AND THEN
TRACKS EAST AND OPENS UP ROTATING AROUND A LONGER WAVE TROUGH
SHIFTING EAST TOWARD THE COAST THROUGH SUNDAY. THE ASSOCIATED SFC
LOW WILL TRACK OVER FLORIDA ON SUNDAY AND THEN EAST INTO THE
ATLANTIC BY MONDAY MORNING AS COLD FRONT DRIVES FARTHER SOUTH. SHOULD
SEE BEST CHC OF SHWRS/TSTMS IN WARM MOIST UNSTABLE AIR AHEAD OF
COLD FRONT AS IT APPROACHES LATE SATURDAY. IF THIS LOW REMAINS ON
THIS SOUTHERN TRACK AS GFS DEPICTS IN LATEST MODEL RUN...THE BEST PCP
MAY REMAIN OFF SHORE ON SUNDAY WITH COLD FRONT ALREADY SOUTH OF
AREA. THIS WILL LEAVE BEST CHC OF PCP ALONG THE COAST AND OFF
SHORE. PCP WATER VALUES AHEAD OF COLD FRONT REACH UP NEAR 1.4
INCHES BUT THE REAL MOISTURE RICH AIR WITH PCP WATER VALUES UP
NEAR 1.8 INCHES MAY REMAIN JUST OFF SHORE.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...BY SUNDAY AFTERNOON WINDS VEER AROUND TO
THE NW AS COLD FRONT MOVES SOUTH AND LOW SHIFTS FARTHER EAST. PCP
WATER VALUES DROP BELOW AN INCH BY LATE SUNDAY AS PLENTY OF COOL
AND DRY AIR MAKES ITS WAY INTO AREA SUN NIGHT INTO MON. HIGH
PRESSURE WILL BUILD INTO AREA BEHIND COLD FRONT MON THROUGH TUES.
A DEEP NW FLOW WILL CONTINUE ON BACK END OF DEEP MID TO UPPER
TROUGH AS IT SLOWLY SHIFTS OFF SHORE THROUGH WEDNESDAY. MAY SEE
SOME CLOUDS DEVELOP AS VORT MAX ROTATES AROUND MID TO UPPER TROUGH
AS IT SHIFTS OFF SHORE BUT OVERALL EXPECT COOL AND DRY WEATHER MON
THROUGH WED. GUSTY NORTHWEST WINDS ON BACK END OF SYSTEM ON MONDAY
WILL WEAKEN AS LOW LIFTS OFF TO THE NORTHEAST TUES INTO WED. A
WARMER RETURN FLOW WILL SET UP MID WEEK AS HIGH SHIFTS OFF SHORE.
TEMPS ON SUNDAY WILL BEGIN TO DROP AS COLD FRONT MAKES ITS WAY
THROUGH. SHOULD SEE TEMPS UP AROUND 70 ON SUNDAY BUT BY MONDAY CAA
WILL BE IN FULL FORCE WITH GUSTY NW WINDS KEEPING TEMPS IN THE MID
60S MOST PLACES. 850 TEMPS DROP OUT FROM UP AROUND 11C SUN MORNING
DOWN TO AROUND 2 C BY MON AFTN WITH LITTLE REBOUND UNTIL RETURN
FLOW SETS UP WED AFTN. AS GRADIENT WEAKENS WINDS WILL BECOME
LIGHTER AND EXPECT BETTER RADIATIONAL COOLING MON AND TUES NIGHT.
WITH PLENTY OF DRY AIR IN PLACE EXPECT DECENT DIURNAL SWINGS IN
TEMPS MON THROUGH WED. HIGHS SHOULD JUST REACH INTO THE 70S TUES
AND SLIGHTLY WARMER ON WED BUT DAYS WILL START OUT COOL WITH
OVERNIGHT LOWS BETWEEN 40 AND 45 MOST PLACES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...LIGHT SHOWER ACTIVITY WILL LINGER ALONG THE COAST FOR
THE NEXT FEW HOURS. AN APPROACHING WEAK SHORTWAVE TROUGH ALOFT MAY
CAUSE A RESURGENCE OF SHOWERS INTO THE MYRTLE BEACH AREA AFTER
10-11Z...BUT MODEL GUIDANCE IS NOT CONSISTENT IN THIS IDEA. IFR CIGS
INLAND MAY FRAGMENT AT TIMES DUE TO A DIVERGENT LOW-LEVEL FLOW BELOW
2000 FT AGL NOTED IN RUC AND NAM MODEL DATA. THE COLD FRONT WILL
STALL JUST OFFSHORE LATER THIS AFTERNOON...WITH A CONTINUED LOW
CHANCE OF SHOWERS...MAINLY NEAR THE COAST.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH ISOLATED SHOWERS FRIDAY.
INTERMITTENT MVFR/POSSIBLE IFR CONDITIONS WITH SCATTERED SHOWERS
SATURDAY. NUMEROUS SHOWERS POSSIBLE SUNDAY...MAINLY NEAR THE COAST.
VFR MONDAY WITH ISOLATED SHOWERS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM THURSDAY...A WEAK COLD FRONT WILL DRIFT A LITTLE
FARTHER OFFSHORE THIS MORNING...THEN SHOULD STALL FROM ABOUT 20
MILES EAST OF CAPE FEAR TO 50 MILES EAST OF MYRTLE BEACH. THERE IS A
VERY WEAK PRESSURE GRADIENT SURROUNDING THIS FRONT SO WE ANTICIPATE
LIGHT WIND SPEEDS THROUGH TONIGHT REGARDLESS OF DIRECTION. A MAINLY
NORTH WIND THIS MORNING SHOULD VEER MORE EASTERLY THIS AFTERNOON
WITH A WEAK SEABREEZE DEVELOPING...THEN BACK TO THE NORTHEAST
TONIGHT. SCATTERED SHOWERS AND PERHAPS AN ISOLATED T-STORM ARE
POSSIBLE WITH THE FRONT IN THE VICINITY...BUT THERE IS ONLY ONE WEAK
MID-LEVEL DISTURBANCE THAT MIGHT HELP FOCUS ACTIVITY IN THE
GEORGETOWN AND MYRTLE BEACH VICINITY LATE THIS MORNING.
BUOY OBSERVATIONS SHOW SURPRISINGLY LARGE SEAS GIVEN THE WEAK WINDS
OBSERVED. SPECTRAL WAVE PLOTS FROM FRYING PAN SHOALS REVEAL
VIRTUALLY ALL THE WAVE ENERGY IS DUE TO A 15-SECOND SWELL THAT HAS
ARRIVED SEVERAL HOURS SOONER THAN ANY OF THE WAVE MODELS INDICATED.
FOR THE WATERS EAST OF CAPE FEAR SEAS COULD BUILD TO 4 FEET LATER
TODAY...WHILE ACROSS THE SC COASTAL WATERS SEAS COULD BUILD TO 3
FEET IN THE LONG-PERIOD SWELLS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...LINGERING FRONT/TROUGH LIFTS BACK NORTH
AS A WARM FRONT EARLY FRIDAY...TURNING WINDS TO THE SOUTH AND
INCREASING TO AROUND 10 KTS BY LATE FRIDAY. LONG PERIOD SWELL
DECAYS THROUGH FRIDAY...BUT INCREASING SOUTHERLY WIND WAVES KEEP
OVERALL WAVE HEIGHTS AT 2-4 FT. WINDS WILL INCREASE FURTHER ON
SATURDAY UP TO 15 TO 20 KTS AS GRADIENT TIGHTENS AS COLD FRONT
APPROACHES FROM THE NORTHWEST AND LOW DEEPENS OVER THE GULF COAST.
THIS WILL PUSH SEAS UP NEAR SCA CONDITIONS BY SAT NIGHT. THE GFS
HAS BACKED OFF ON THE SEAS A BIT AS LATEST RUN KEEPS LOW RIDING BY
FARTHER SOUTH WITH A NORTHERLY FLOW SETTING UP ON BACK END BY SUN
AFTN. THEREFORE SEAS MAY PEAK UP AROUND 6 TO 7 FT RATHER THAN THE
11 FT PROJECTED IN EARLY RUNS. THE STRENGTH AND DIRECTION OF WINDS
AND BUILD UP OF SEAS WILL BE HIGHLY DEPENDENT ON THE TRACK AND
STRENGTH OF THIS LOW AND THEREFORE MAY CHANGE AGAIN.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...WINDS WILL VEER AROUND TO THE W-NW SUN
INTO MONDAY AS LOW LIFTS OFF TO THE NORTHEAST DRAGGING A COLD
FRONT FARTHER SOUTH. SEAS WILL DIMINISH BUT EXPECT A DECENT SURGE
BEHIND FRONT KEEPING SEAS UP NEAR SCA CONDITIONS THROUGH MONDAY. THE
OFF SHORE WINDS OUT OF THE W-NW BEHIND COLD FRONT WILL VEER TO THE
NORTH AND ALLOW NEAR SHORE SEAS TO DROP BUT OVERALL WILL MAINTAIN
SEAS UP NEAR 3 TO 5 FT THROUGH MON AFTN. GRADIENT WILL WEAKEN AS
LOW LIFTS OFF MOVING FARTHER AWAY AND HIGH PRESSURE BUILDS IN
THROUGH TUESDAY. NORTHERLY WINDS WILL DIMINISH TO 10 TO 15 KTS
LATE MON INTO EARLY TUES AND SEAS WILL DROP TO 2 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
128 AM EDT THU APR 19 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DROP SLOWLY SOUTHEAST ACROSS THE AREA THROUGH
TONIGHT...STALLING ALONG THE COAST ON THURSDAY. THIS FRONT WILL
MOVE BACK NORTH AS A WARM FRONT ON FRIDAY. A STRONGER COLD FRONT
IS EXPECTED SUNDAY WITH THE POTENTIAL FOR STRONG THUNDERSTORMS
AHEAD OF IT. COOL AND DRY HIGH PRESSURE WILL BUILD IN EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 130 AM THURSDAY...MADE SOME ADJUSTMENTS TO WINDS...
TEMPERATURES...AND POPS/WX THROUGH DAYBREAK USING THE LATEST HRRR
MODEL WHICH SEEMS TO MATCH CURRENT SURFACE DEPICTION PRETTY WELL.
THE SURFACE FRONT IS OFF THE SC COAST AND JUST MOVED THROUGH ILM IN
THE PAST HOUR. LIGHT NORTH SURFACE WINDS ARE NOT TAPPING ANY
SIGNIFICANT RESERVOIR OF COLD AIR SO LOWS WILL ONLY FALL INTO THE
MID 50S INLAND...AND UPPER 50S TO NEAR 60 AT THE COAST. AN
APPROACHING WEAK SHORTWAVE TROUGH FROM THE SOUTHWEST MAY CAUSE A
RESURGENCE OF SHOWER ACTIVITY SOUTH OF FLORENCE AND INTO THE
GEORGETOWN-MYRTLE BEACH AREA AFTER 4 AM. MODEL GUIDANCE IS NOT
UNANIMOUS IN THIS IDEA BUT WE HAVE INCREASED POPS BACK INTO THE
40-50 PERCENT RANGE AT THAT TIME GIVEN THE RADAR COMPOSITES SHOWING
SHOWERS IN EASTERN GEORGIA.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...COMPLEX AND SLIGHTLY UNSETTLED WEATHER
THROUGH THE SHORT TERM AS A WARM MOIST AIRMASS SITS OVER THE
CAROLINAS.
WEAK COLD FRONT WILL BE EXITING THE COAST AT THE START OF THE
PERIOD...BUT WILL STALL RIGHT ALONG...OR JUST OFF...THE COAST DURING
THURSDAY. THE BAROCLINIC GRADIENT ALONG THIS FRONT WILL
DISSIPATE...BECOMING AN INVERTED COASTAL-TYPE TROUGH ALONG THE
SOUTHEAST COAST. THIS BOUNDARY WILL SERVE AS A FOCUS FOR POTENTIAL
CONVECTION DURING THURSDAY...ESPECIALLY ALONG THE COAST...AND BEST
CHANCE FOR TSTMS WILL BE ALONG ANY SEA BREEZE RESULTANT. INSTABILITY
PARAMETERS FAVOR TSTMS...BUT THERE IS VERY LIMITED UPPER
SUPPORT...IN FACT WEAK NVA MAY OCCUR HERE BEHIND A DEPARTING S/W
TROUGH. STILL...WILL CARRY CHC POP ALONG THE COAST ALL DAY WHERE
SREF PROBS EXCEED 50%...AND SCHC INLAND THROUGH THE AFTN WITH
SHOWERS/TSTMS IN AN ENVIRONMENT WITH PWATS STAYING ABOVE 1 INCH.
FAVOR THE MET NUMBERS THURSDAY DUE TO CLOUD COVER...WITH LOW TO MID
70S ACROSS THE AREA. E/NE FLOW AT NIGHT WILL PERMIT TEMPS TO FALL
INTO THE MID/UPPER 50S EVEN WITH SUBSTANTIAL CLOUD COVER CONTINUING.
COASTAL TROUGH RETURNS NORTH AS A WARM FRONT DURING FRIDAY. ONCE
AGAIN...ENOUGH INSTABILITY WILL BE PRESENT...ESPECIALLY IN A
MOISTENING AIRMASS BEHIND THE WARM FRONT...TO CARRY CHC POP ACROSS
THE AREA DURING THE AFTN...FOCUSED PRIMARILY ALONG THE LIFTING WARM
FRONT. EXPECT LESS COVERAGE ON FRIDAY THAN THURSDAY...AND MUCH OF
THE DAY WILL LIKELY BE JUST PARTLY CLOUDY. WARM SOUTHERLY FLOW WILL
WARM TEMPS INTO THE UPPER 70S TO LOW 80S...WITH MINS AT NIGHT ONLY
FALLING INTO THE LOW 60S WITH CONTINUED WARM WINDS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...ALL EYES REMAIN ON THE SIGNIFICANT
SYSTEM TO MOVE ACROSS THE GULF OF MEXICO AND SUBSEQUENTLY THE EAST
COAST FOR THE WEEKEND INTO EARLY NEXT WEEK.
STILL SOME DIFFERENCES IN THE DETAILS AND TIMING AS THE ECMWF
ENSEMBLE MEAN...WHICH HPC PREFERS...IS A BIT SLOWER. OVERALL THIS
WARRANTS FEW CHANGES IN THE INHERITED FORECAST. I HAVE INCREASED
POPS TO LIKELY FOR SUNDAY AND EXTENDED THE POPS SLIGHTLY IN TIME FOR
MONDAY.
THE BEST FORCING APPEARS TO MANIFEST ITSELF IN AREAS OF 500-700MB
DEFORMATION AND WITH A SIGNIFICANT SUBTROPICAL PLUME OF
MOISTURE...PRECIPITABLE WATER VALUES OF 1.70 INCHES...SOUTH TO NORTH
LINES OF SHOWERS AND THUNDERSTORMS...NOT UNLIKE WHAT WE SEE TO OUR
WEST CURRENTLY ARE LIKELY. IT GOES WITHOUT SAYING THIS COULD BRING
THE AREA BENEFICIAL RAINS.
A QUICK LOOK AT WIND FIELDS SHOW LOW LEVEL WINDS...925MB TO 850MB
WINDS NOT OVERLY IMPRESSIVE...THIRTY KNOTS. HOWEVER WITH AMPLE
INSTABILITY AND THE MID LEVEL LOW/TROUGH GOING NEGATIVE TILT...AS
WITH HPCS OFFICIAL FORECAST...ENHANCED HELICITY COULD DEVELOP AND IF
THE TIMING WERE COUPLED WITH DAYTIME HEATING POCKETS...A THREAT
COULD DEVELOP. WILL LET LATER SHIFTS ADDRESS THIS THREAT.
FINALLY...THE TEMPERATURE FORECAST REQUIRED LITTLE EDITING MAINLY TO
COME INTO BETTER AGREEMENT WITH ADJACENT OFFICES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...LIGHT SHOWER ACTIVITY WILL LINGER ALONG THE COAST FOR
THE NEXT FEW HOURS. AN APPROACHING WEAK SHORTWAVE TROUGH ALOFT MAY
CAUSE A RESURGENCE OF SHOWERS INTO THE MYRTLE BEACH AREA AFTER
10-11Z...BUT MODEL GUIDANCE IS NOT CONSISTENT IN THIS IDEA. IFR CIGS
INLAND MAY FRAGMENT AT TIMES DUE TO A DIVERGENT LOW-LEVEL FLOW BELOW
2000 FT AGL NOTED IN RUC AND NAM MODEL DATA. THE COLD FRONT WILL
STALL JUST OFFSHORE LATER THIS AFTERNOON...WITH A CONTINUED LOW
CHANCE OF SHOWERS...MAINLY NEAR THE COAST.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH ISOLATED SHOWERS FRIDAY.
INTERMITTENT MVFR/POSSIBLE IFR CONDITIONS WITH SCATTERED SHOWERS
SATURDAY. NUMEROUS SHOWERS POSSIBLE SUNDAY...MAINLY NEAR THE COAST.
VFR MONDAY WITH ISOLATED SHOWERS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...NO SIGNIFICANT CHANGES FROM THE PRIOR
FORECAST UPDATE. THE FRONT IS OFF THE SC COAST BUT WILL TAKE ANOTHER
2-3 HOURS TO MOVE OUT INTO THE WATERS E OF CAPE FEAR. PREVIOUS
DISCUSSION FROM 10 PM FOLLOWS...
THE WEAK COLD FRONT WILL TRACK/MOVE VERY SLOWLY SOUTHEAST ACROSS THE
EASTERN CAROLINAS TO THE COASTAL WATERS OVERNIGHT INTO THURSDAY. THE
MAJORITY OF THE ILM COASTAL WATERS WILL REMAIN SOUTH OF THE FRONT
OVERNIGHT...WITH WINDS STAYING GENERALLY SOUTH TO SOUTHEAST AND
LIGHT...10 KTS OR LESS.
INITIALLY...SIGNIFICANT SEAS WILL BE A FUNCTION OF LOCALLY PRODUCED
WIND WAVES WITH PERIODS OF 4 TO 6 SECONDS. WAVEWATCH3 AND LOCAL SWAN
INDICATE A 1-2 FOOT EASTERLY GROUND SWELL EXHIBITING 12 TO 15 SECOND
PERIODS AFFECTING PORTIONS OF THE ILM WATERS THIS EVENING...THEN
BECOMING WIDESPREAD BY DAYBREAK THURSDAY. A FURTHER INCREASE IN THE
SEA HEIGHTS FROM THIS GROUND SWELL TO OCCUR ON THURSDAY.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...WEAKENING COLD FRONT/INVERTED COASTAL
TROUGH WILL BE OVER THE WATERS EARLY THURSDAY. THIS CREATES LIGHT
SOUTHERLY FLOW MUCH OF THURSDAY...BEFORE THIS BOUNDARY GETS
SUPPRESSED FAR ENOUGH TO THE SOUTH FOR WINDS TO BECOME E/NE BY
THURSDAY NIGHT. THE WEAK PRESSURE GRADIENT WILL KEEP WINDS LESS THAN
10 KTS THOUGH...SO THE 2-4 FT SEAS WILL BE FROM A COMBINATION OF A
2-3FT/12SEC EASTERLY SWELL AND BACKING WIND WAVES. BOUNDARY LIFTS
BACK NORTH AS A WARM FRONT EARLY FRIDAY...TURNING WINDS TO THE SOUTH
AND INCREASING TO AROUND 10 KTS BY LATE FRIDAY. LONG PERIOD SWELL
DECAYS ON FRIDAY...BUT INCREASING SOUTHERLY WIND WAVES KEEP OVERALL
WAVE HEIGHTS AT 2-4 FT.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...LOWER CONFIDENCE IN THE WIND FORECAST AT
LEAST FROM A DIRECTION STANDPOINT AS A SIGNIFICANT SYSTEM WILL BE
MOVING SLOWLY UP THE EAST COAST. CONTINUED TO ADVERTISE SOUTHERLY
WINDS OF 15-20 KNOTS FOR SATURDAY AND SUNDAY FOR THAT MATTER. LOW
MOVING UP THE COAST ALLOWS WINDS TO SHIFT TO WEST TO NORTHWEST
MONDAY. WITH THE STRONG AND PROLONGED SOUTHERLY FETCH SEAS WILL BE
MORE OF A CONCERN FOR MARINERS AND VALUES WILL QUICKLY RAMP UP
FROM 2-4 FEET TO 7-10 FEET SUNDAY. HIGHER SEAS WILL PREVAIL INTO
MONDAY ALTHOUGH OFFSHORE FLOW WILL KNOCK THEM DOWN SOMEWHAT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...HDL
LONG TERM...SHK
AVIATION...TRA
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
815 PM CDT FRI APR 20 2012
.DISCUSSION...FARILY STRONG WAVE SEEN ON WATER VAPOR IMAGERY
APPROACHING THE REGION FROM THE NORTHWEST. A BAND OF SHOWERS HAS
DEVELOPED ACROSS WESTERN AND CENTRAL NORTH DAKOTA ASSOCIATED WITH
700MB FRONTOGENESIS. THIS FORCING AND ASSOCIATED SHOWERS WILL
PROPAGATE THROUGH THE FA QUICKER THAN CURRENT FORECAST...AND WILL
NEED TO SPEED UP THE ONSET OF SHOWERS. FOLLOWED HRRR FOR TIMING OF
HIGHER POPS OVERNIGHT. SHORTWAVE WILL THEN PROPAGATE FROM THE NW
FA INTO THE SE FA FROM 12Z TO 18Z SATURDAY...WITH SHOWERS LIKELY
CONTINUING ALONG AND EAST OF THIS LINE (WHERE HIGHER QPF 0.20 TO
0.40 INCHES WILL LIKELY OCCUR) DISSIPATING BY SATURDAY EVENING.
&&
.AVIATION...PRIMARILY LOOKING AT VFR CONDITIONS MOST OF THE
PERIOD. WILL LIKELY SEE PERIODS OF MVFR CIGS ALONG WITH SHOWERS
INTO SATURDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 312 PM CDT FRI APR 20 2012/
SHORT TERM...
MAIN CHALLENGE FOR THIS PACKAGE IS TIMING OF SYSTEM CROSSING THE FA
TONIGHT INTO SATURDAY.
SATELLITE LOOP SHOWS A WAVE MOVING ACROSS MT AND WILL ENTER INTO ND
THIS EVENING. MODELS INDICATE DECENT ISENTROPIC LIFT AT THE 300K
SFC AND CONDENSATION PRESSURE DEFICITS FAVOR PCPN OVERNIGHT INTO
SATURDAY. FORECAST SOUNDINGS INDICATE INCREASED MID LEVEL MOISTURE
AND SHOWS THE COLUMN SATURATING UP TO 500MB. FORECAST SHOWALTER
INDICIES REMAIN AROUND ZERO TO +1 SO CONFIDENCE NOT HIGH ON
THUNDER...BUT WILL LEAVE MENTION IN FOR NOW. OTHERWISE...PCPN WILL
MOVE INTO THE EASTERN CWA DURING THE DAY ON SATURDAY. TEMP FORECASTS
FOR SATURDAY STILL LOOK GOOD AND NO SIGNIFICANT ADJUSTMENTS WERE
MADE ATTM.
NORTHWESTERLY FLOW ALOFT CONTINUES THROUGH THE REST OF THE
PERIOD...WITH ANOTHER SHORTWAVE MOVING DOWN FROM MANITOBA INTO MN BY
SUNDAY. MOST OF THE ACTIVITY WITH THIS SHORTWAVE WILL BE ACROSS THE
ARROWHEAD OF MINNESOTA...BUT KEPT LOW POPS IN THE LAKE OF THE WOODS
AREA. TEMPS SHOULD BE A BIT WARMER ON SUNDAY AS THE UPPER RIDGE
AMPLIFIES A BIT AND SHIFTS EAST.
LONG TERM...
MID LEVEL RIDGE AXIS TO REMAIN ACROSS THE ROCKIES THROUGH THE LONG
RANGE PERIOD. WEAK LOW SLIDES DOWN THE FRONT OF THE RIDGE BRINGING
SOME LOW PCPN CHANCES MIDWEEK. HIGH PRESSURE TO BUILD IN FOR DRY
CONDITIONS LATER PART OF WORK WEEK ALONG WITH COOLER TEMPERATURES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
407 AM EDT THU APR 19 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH QUEBEC TODAY WITH A COLD FRONT
STALLING NEAR LAKE ERIE. THE FRONT WILL LIFT BACK NORTH TONIGHT
AS A WARM FRONT. ANOTHER LOW WILL MOVE ACROSS THE GREAT LAKES FRIDAY AND
ITS ASSOCIATED COLD FRONT WILL MOVE ACROSS THE REGION FRIDAY
AFTERNOON AND EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD
INTO THE AREA FOR THE LATTER PART OF THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FRONTAL BOUNDARY WILL BE MOVING TOWARD EXTREME NORTHERN OHIO AND
NORTHWEST PA TODAY. BASED ON THE MOISTURE...OMEGA...THE HRRR MODEL
AND THE OTHERS...WILL MENTION POPS BETWEEN 20 AND 30 PERCENT ACROSS
THE EXTREME NORTHERN PORTION OF THE FORECAST AREA. ELSEWHERE PARTLY
CLOUDY AND DRY. WENT CLOSE TO THE WARMER MET MOS AS TEMPERATURES
SHOULD WARM IN THE SOUTHWEST FLOW. THE GRADIENT WILL BE WEAK
ENOUGH FOR A LAKE BREEZE TO DEVELOP. IT COULD GET UP TO 5 MILES
INLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE FRONTAL BOUNDARY WILL LIFT NORTH TONIGHT. SKIES WILL BE PARTLY
CLOUDY. USED A MIX OF THE MOS GUIDANCE FOR THE LOWS.
FRIDAY IS INTERESTING. THE MODELS AGREE WITH A COLD FRONT MOVING
THROUGH DURING THE AFTERNOON AND EARLY EVENING. MAINLY THE ECMWF KEEPS
MOST OF THE PRECIPITATION BEHIND THE FRONT. I AM NOT COMPLETELY
BUYING THAT WITH A MODEST SOUTHWEST FLOW AHEAD OF IT...INCLUDING
SOME OMEGA AND SOME MOISTURE. WILL NOT GO AS HIGH OF POPS AS I
WANT...BUT WILL HAVE A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE
AFTERNOON OVER MUCH OF THE FORECAST AREA AND THEN LIKELY POPS
FRIDAY NIGHT. UNTIL THE INCONSISTENCIES CAN BE CLEARED UP THIS
SEEMS TO BE THE BEST WAY TO GO. WITH THE SOUTHWEST FLOW...TENDED
TOWARD THE WARMER MOS GUIDANCE...EVEN WITH SOME CLOUDS.
STILL SOME CONFLICT WITH THE FORECAST FOR SATURDAY THROUGH SUNDAY
NIGHT. HOWEVER...THE 00Z ECMWF DOESN`T SEEM TO BE AS PESSIMISTIC AS THE 12Z
RUN WAS. KEPT POPS ON THE CHANCE SIDE DURING THIS PERIOD. WITH THE
LAKE AND 850 MB TEMPERATURE DIFFERENCE EXPECTED TO BE NEAR
14C...SOME LAKE EFFECT/LAKE INDUCED SHOWERS WILL BE OCCURRING OVER
NORTHEAST OHIO AND NORTHWEST PA. ATTM KEPT IT JUST RAIN. MUCH OF
THE WESTERN PORTION OF THE FORECAST AREA WILL BE DRY. USED A BLEND
OF THE GUIDANCE FOR THE TEMPERATURES.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
COOL UPPER LOW/TROUGH WILL BE ACROSS NEW ENGLAND STILL EARLY NEXT
WEEK...BUT WITH IT BEGINNING TO PULL AWAY...TEMPERATURES WILL START
TO TREND WARMER HERE. TUESDAY HIGH PRESSURE OVERHEAD...THEN A WARM
FRONT LIFTS ACROSS THE AREA FOR WEDNESDAY. THERE IS GENERAL
AGREEMENT ON THIS BEING THE BIG PICTURE FOR THE LONG TERM AMONGST
THE MODELS. HAVE SOME LINGERING LOW PRECIP CHANCES FOR MONDAY WITH
ANY LEFTOVER ENERGY ROTATING AROUND THE UPPER LOW. THE WARM FRONT
MAY ALSO HAVE SOME PRECIP WITH IT...BUT UNTIL THERE IS BETTER
CONFIDENCE IN ITS TIMING/POSITION WILL LEAVE OUT FOR NOW. THE WORK
WEEK STARTS WITH HIGH TEMPS AROUND 50 MONDAY...BUT STEADILY CLIMBS
TOWARD THE 60S FOR WEDNESDAY.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
CAN NOT RULE OUT A SHOWER DEVELOPING TODAY FOR FAR NORTHERN OH/NW
PA AS A COLD FRONT STALLS IN THE VICINITY OF THE LAKE TODAY. HAVE
SOME VCSH MENTIONED...BUT THEY SHOULD BE QUITE ISOLATED. MID LEVEL
CLOUDS WILL INCREASE THIS MORNING...BUT CONDITIONS TO REMAIN VFR.
LATE THURSDAY NIGHT FRONT WILL BEGIN TO PUSH NORTH AGAIN.
.OUTLOOK...NON VFR POSSIBLE FRIDAY NIGHT INTO SATURDAY MORNING.
&&
.MARINE...
A COLD FRONT WILL SAG SOUTH AND STALL IN THE VICINITY OF THE LAKE
TODAY. IT WILL PUSH BACK NORTH LATE TONIGHT. LOW PRESSURE AND THE
COLD FRONT WILL COME ACROSS THE EASTERN LAKES ON FRIDAY INTO
SATURDAY. NOT EXPECTING ANY MARINE HEADLINES FOR THE LAKE UNTIL
AFTER THAT COLD FRONTAL PASSAGE IN THE COLD AIR ADVECTION. COULD SEE
SMALL CRAFT ADV FRIDAY NIGHT INTO SATURDAY. HIGH PRESSURE SETTLES
OVER THE LAKE FOR SUNDAY INTO MONDAY WITH A LIGHT NORTHERLY FLOW.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS MEDFORD OR
847 PM PDT FRI APR 20 2012
.SHORT TERM...THE FORECAST IS ON TRACK. HIGH PRESSURE WILL
CONTINUE TO BUILD OVER THE AREA TONIGHT INTO TOMORROW. THIS WILL
BRING CLEAR SKIES INLAND. ALONG THE COAST LOW STRATUS AND FOG WILL
CONTINUE TONIGHT AND IS EXPECTED TO SPREAD INLAND INTO THE UMPQUA
BASIN TONIGHT. CURRENT RUC AND NAM FORECASTS INDICATE THESE LOW
CLOUDS WILL CLEAR IN THE LATE MORNING TOMORROW. TEMPERATURES WILL
WARM INTO THE UPPER 70S TO LOW 80S FOR INLAND VALLEYS AND INTO THE
LOW TO MID 60S ALONG THE COAST. MODELS ARE SHOWING SOME LIGHT
PRECIPITATION AND WEAK INSTABILITY OVER THE CASCADES AND EASTERN
AREAS TOMORROW. HOWEVER...WITH NO OBVIOUS TRIGGER EXPECT ONLY
CUMULUS CLOUD DEVELOPMENT SIMILAR TO TODAY. MODELS CONTINUE TO
SHOW WEAK DISTURBANCES IN THE FLOW AND CONTINUE INSTABILITY WITH A
SLIGHT CHANCE FOR THUNDERSTORMS ON SUNDAY. THE CHANCE FOR
THUNDERSTORMS INCREASES MONDAY AS A LOW APPROACHES THE COAST AND
MODELS TRACK A MORE SIGNIFICANT VORTICITY MAX INTO THE AREA IN
SOUTHERLY FLOW.
&&
.AVIATION...EXPECT VFR CIGS AND VIS OVER MOST INLAND AREAS THIS
EVENING THROUGH SATURDAY AFTERNOON AS A RIDGE ALOFT GRADUALLY
BUILDS OVER THE PACNW. THE EXCEPTION WILL BE AT THE COAST WHERE
IFR/LIFR CIGS AND VIS WILL PERSIST INTO THE MORNING...BECOMING VFR
WITH AREAS OF MVFR CIGS BY EARLY AFTERNOON. STRATUS WITH IFR/LIFR
CIGS MAY ALSO SPILL INTO THE UMPQUA BASIN INCLUDING KRBG LATE
TONIGHT AND PERSIST THROUGH MID MORNING.
&&
.PREV DISCUSSION... /ISSUED 128 PM PDT FRI APR 20 2012/
SHORT TERM...SKIES HAVE CLEARED OUT OVER SW OREGON AND NORCAL
THIS AFTERNOON, WITH THE EXCEPTION OF THE COAST WHERE CONSIDERABLE
STRATUS REMAINS. IT SHOULD GRADUALLY ERODE THERE AS WELL THIS
AFTERNOON, BUT IT WILL BE TOUGHER TO GET RID OF ENTIRELY RIGHT AT
THE COASTLINE DUE TO THE CONTINUED ONSHORE FLOW. STRATUS SHOULD
RETURN TO THE IMMEDIATE COASTLINE TONIGHT AND CONTINUE INTO
TOMORROW.
A RIDGE WILL CONTINUE TO BUILD OVER THE WESTERN U.S. THIS WEEKEND
AS A BIG CUTOFF LOW DROPS SOUTH ALONG 140W. WHILE WE ARE IN
BETWEEN THE TWO AND NOT ENTIRELY UNDER THE RIDGE ALL WEEKEND, WE
WILL SEE SIGNIFICANT SOUTHERLY WARM ADVECTION RESULTING IN
UNSEASONABLY WARM WEATHER FOR A CHANGE. THE EXCEPTION WILL BE
ALONG THE COAST, BUT EVEN THERE TEMPS SHOULD BE WARMER THAN WE`VE
SEEN LATELY. HIGHS FOR MOST OF US WILL LIKELY TOP OUT IN THE 70S
TODAY WITH MANY LOWER ELEVATION LOCATIONS REACHING THE 80S
TOMORROW AND SUNDAY. THE RECORD HIGHS FOR MEDFORD FOR SAT, SUN AND
MON ARE 92, 84, AND 86, RESPECTIVELY. TOMORROW`S RECORD IS LIKELY
OUT OF REACH, BUT THE RECORD FOR SUNDAY IS NOT ONLY WITHIN REACH,
BUT OUR FORECAST IS ACTUALLY TO BREAK THAT.
SINCE THINGS ARE LARGELY ON TRACK FOR THIS WEEKEND, I HAVEN`T MADE
MANY CHANGES. SUNDAY STILL LOOKS QUITE UNSTABLE, BUT LACKS MUCH OF
A TRIGGERING MECHANISM TO GET STORMS GOING. COULD SEE SOME FIRE
OFF THE HIGHER TERRAIN, BUT AM NOT REAL IMPRESSED AT THIS TIME.
BUT I DID KEEP AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS FOR
SUNDAY AFTERNOON.
THE LARGEST CHANGE IN THE FORECAST WAS FOR MONDAY. THE MODELS NOW
AGREE IN KEEPING THE LOW OFFSHORE AS IT DROPS SOUTH WHICH ALLOWS
OUR WARM WEATHER TO CONTINUE. HOW WARM WE GET ON MONDAY DEPENDS A
LOT ON HOW MUCH WE CUE UP DURING THE AFTERNOON AND HOW WIDESPREAD
THE RESULTING SHOWERS AND STORMS MAY BE, BUT I DID RAISE TEMPS
QUITE A BIT. WITH A WEAK SHORT WAVE PROGGED TO MOVE THROUGH THE
SOUTHERLY FLOW, THINK THERE IS A MUCH GREATER POTENTIAL FOR
SHOWERS/STORMS MONDAY COMPARED TO SUNDAY. FOR THAT REASON, I HAVE
INCREASED POPS AREA-WIDE, BUT I WOULD STILL EXPECT STORMS TO
FORM PRIMARILY OVER THE MOUNTAINS AND THEN DRIFT OUT OVER THE
VALLEYS IN THE SOUTHERLY FLOW ALOFT. -WRIGHT
LONG TERM...TUESDAY THROUGH FRIDAY. THE EXTENDED FORECAST REMAINS
UNCERTAIN AT THIS TIME...BUT CONFIDENCE IS RISING DUE TO A GROWING
CONCENSUS THAT ANY CUTOFF LOWS THAT DO FORM WILL BE TOO FAR AWAY TO
AFFECT THE PACIFIC NORTHWEST.
ALL OF THE MEDIUM RANGE MODELS START OFF THE EXTENDED PERIOD WITH A
STRONG RIDGE OVER THE INTERMOUNTAIN STATES AND A LONG WAVE TROUGH
OFFSHORE BETWEEN 130W AND 140W. AT THE BASE OF THIS TROUGH THERE
WILL BE A LOW THAT WILL INITIALLY BE COMPLETELY CUTOFF (EC)...OR NOT
(DGEX) OR SOMEWHERE IN BETWEEN (GFS). HOWEVER...ALL THREE MODELS
KEEP THE LOW TOO FAR SOUTH TO HAVE MUCH EFFECT ON THE PACIFIC
NORTHWEST WEATHER THROUGH THE NEXT WEEK. THEREFORE...ATTENTION TURNS
TO THE NORTHERN BRANCH OF THE SPLIT FLOW...AND THERE IS BETTER
AGREEMENT AMONG THE MODEL SOLUTIONS WITH THAT FEATURE.
INITIALLY THE OFFSHORE TROUGH...SANS THE CUTOFF...WILL BE WEAK...BUT
IT WILL DIG IN PLACE MIDWEEK AS UPSTREAM SHORT WAVE ENERGY FEEDS
INTO IT. THE TROUGH WILL EVENTUALLY PROGRESS TO THE COAST
FRIDAY...BUT IT WILL WEAKEN AS IT DOES SO.
SO...TUESDAY INTO WEDNESDAY THE FLOW ALOFT WILL REMAIN SOUTH TO
SOUTHWEST OVER THE AREA...AND THIS FLOW WILL FEED CONVECTION.
THE INCOMING TROUGH WILL PUSH A FRONT ONSHORE WEDNESDAY NIGHT INTO
THURSDAY...AND BOTH THE EC AND THE GFS AGREE NOW THAT THIS WILL BE A
WET SYSTEM. THE COLD CORE TROUGH WILL THEN FOLLOW FOR COOL AND
UNSETTLED SHOWERY WEATHER FRIDAY.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PZ...NONE.
$$
CC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
750 PM EDT FRI APR 20 2012
.SYNOPSIS...
UNSEASONABLY MILD CONDITIONS WILL PREVAIL THROUGH THIS EVENING. A
COLD FRONT TRAILING SOUTH OF LOW PRESSURE...THAT WILL BE MOVING TO
THE NORTH OF THE AREA SHOULD PASS THROUGH THE STATE ON SATURDAY AND
BECOME NEARLY STATIONARY ALONG OR JUST OFF THE EASTERN SEABOARD.
SHOWERS AND ISOLATED THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT AS
IT SHIFTS FROM WEST TO EAST ACROSS CENTRAL PENNSYLVANIA THROUGH
TOMORROW NIGHT. A DEEP UPPER TROUGH AND CUT-OFF LOW IS EXPECTED TO
DEVELOP OVER THE MID-ATLANTIC STATES AND BRING COLDER AND MORE
UNSETTLED CONDITIONS TO THE AREA FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
CLEAR TO PARTLY CLOUDY SKIES STILL WIDESPREAD ACROSS THE CWA EARLY
THIS EVENING...WITH JUST SOME FLAT CU AND CIRRUS ROAMING ABOUT.
1003 MB SFC LOW NEAR TORONTO WILL TRACK ENEWD TNT. THE COLD FRONT
TRAILING SSW OF THE LOW WILL REACH NW PA AFT MIDNIGHT.
MDL CONSENSUS CONTINUES TO INDICATE HIGH LKLY/CATG POPS DEVELOPING
ACROSS THE NW MTNS AFT 06Z...THOUGH THE LATEST HRRR HOLDS OFF THE
PRECIP ONSET UNTIL 07-08Z.
THE RELATIVELY MOIST SWLY FLOW AND INC CLOUD COVER SHOULD KEEP
OVRNGT TEMPS MILD IN THE 50S. GUID IS ALSO FAVORING LOW CLOUDS/FOG
DEVELOPING OVR THE ERN 1/3 FROM THE LWR SUSQ/LEHIGH VLYS NWD INTO
THE SRN POCONOS AS MARITIME AIR IS ADVECTED NWD/UPSLOPE VIA SSELY
LOW LVL FLOW.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SFC LOW PRES ASSOCD WITH NRN STREAM MID-UPPER TROUGH PIVOTING EWD
ACRS THE UPPER GRT LKS/ERN CANADA WILL BE MOVG NEWD THRU THE ST
LAWRENCE VLY INTO NRN NEW ENG...WITH ITS TRAILING COLD FRONT
PROGRESSING EWD ACRS CENTRAL PA DURING THE DAY. MDLS ARE IN GOOD
AGREEMENT WITH FROPA TIMING THRU THE ALLEGHENIES BEFORE MID-
DAY..BUT THEN SLOWING FURTHER EAST IN TIME AS A SRN STREAM UPPER
LOW CUTS OFF OVR THE NRN GOMEX AND BEGINS TO INTERACT WITH ADDNL
S/W ENERGY DIVING SEWD THRU THE UPPER MIDWEST.
WIDESPREAD SHOWERS ARE EXPECTED TO DEVELOP ALONG/AHEAD OF THE
COLD FRONT OVR THE CENTRAL MTNS FROM MID MORNING INTO THE EARLY
AFTN WITH THE FOCUS FOR PCPN SHIFTING INTO THE ERN HALF OF THE
STATE LATER IN THE DAY AND INTO SAT NGT. MODEL DATA SUGGESTS THAT
THE ENVIRONMENT WILL BECOME CONDUCIVE FOR CONVECTIVE DEVELOPMENT
OVR SERN PA DURING THE AFTN AND EVE...WITH LOCALLY STG/MARGINALLY
SVR STORMS POSSIBLE VIA THE 16Z UPDATED SPC DY2 OUTLOOK WHICH PLACES
SE 1/3 OF THE CWA IN THE SEE TEXT.
DAY 2 QPF AMTS RANGE FROM AROUND 0.25-0.50" OVER THE WESTERN
ALLEGHENIES EWD INTO THE CENTRAL MTNS...WITH HEAVIER AMTS BTWN
0.50-1 INCHES OVR THE SERN 1/3 OF THE CWA. THE RNFL WILL BE
WELCOMED GIVEN THE ABNORMALLY DRY CONDS THAT HAVE DEVELOPED OVR
THE LAST SEVERAL MONTHS.
THERE SHOULD BE A FAIRLY ROBUST GRADIENT IN TEMPS TOMORROW GIVEN
SHARP FROPA WITH EARLY HIGHS IN THE UPPER 40S IN THE NW MTNS...MID
50S AND 60S OVR THE CENTRAL ZONES AND LOW 70S INTO THE MIDDLE AND
LWR SUSQ VLY. SAT NGT MINS WILL RANGE FROM THE MID 30S OVR THE NRN
AND WRN MTNS TO THE MID 40S ACRS THE CENTRAL AND SRN LOWER
ELEVATIONS.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MUCH HIGHER CONFIDENCE IN THE FORECAST AFTER LOOKING AT THESE
LATEST MODEL FORECASTS FOR SUNDAY INTO MONDAY. THE TROUBLE IS THAT
THE OUTPUT IS LOOKING PRETTY COLD AND PERHAPS SNOWY FOR THE AREA.
UPPER TROUGH DIGS DOWN FROM THE NRN PLAINS SATURDAY INTO SUNDAY
AND AMPLIFY/MERGE WITH A MINOR CUT-OFF ALONG THE GULF COAST. THIS
MEETING WILL EVENTUALLY FORM A SIGNIFICANTLY DEEP CUT-OFF JUST TO
OUR SOUTH AND SLIDE IT RIGHT OVERHEAD EARLY MONDAY. WHATEVER MODEL
YOU CHOOSE TO LOOK AT THIS CYCLE LOOKS SIMILAR IN TIMING AND
INTENSITY. THE SFC LOW PASSES OVER THE MAJOR METRO AREAS ON THE
COAST SUNDAY NIGHT. THIS IS THE BEST NOR-EASTER WE HAVE SEEN IN A
VERY LONG TIME. THE TROUBLE IS THAT IT IS LATE APRIL. WHILE THE
TEMPS GET COLD ENOUGH FOR ALL SNOW THROUGH THE NIGHT ON SUNDAY
NIGHT...THE DAYTIME TEMPS WILL BE TOO MILD OVER MOST OF THE AREA
TO ALLOW ANY SNOW THAT FALLS DURING THE DAY TO STICK. QPF GETS UP
NEAR 2 INCHES OVER THE EASTERN THIRD OF THE STATE...BUT ALL RAIN
THERE. THE HIGHER ELEVATIONS AND THE NW THIRD TO HALF OF THE AREA
WILL BE MOST-LIKELY TO SEE THE WHITE STUFF ON THE GROUND MONDAY
MORNING. TOO EARLY TO START POSTING ANY WATCHES...SINCE IT IS
STILL DAY 3 AND THIS IS THE FIRST REAL CYCLE OF MODEL RUNS WHICH
HAVE AGREED ON THE GENERAL SOLUTION. HAVE PLACED LOTS OF LIKELY
POPS AND SOME LOW-END CATG POPS IN FOR SUN-MON. IT SHOULD
PRECIP...MAINLY RAIN. BUT THE TOUGH CALL IS HOW MUCH SNOW WILL
STICK. FIRST GUESS PUTS A FEW INCHES IN THE NRN MTS AND LAURELS
AND HARDLY ANYTHING SE OF IPT/UNV/AOO. BUT EVEN HERE...AN ACCUM IS
POSSIBLE - SUN NIGHT. MONDAY SHOULD WARM UP DURING THE DAY TO
SQUASH ACCUMS THEN...BUT WRAP AROUND KEEPS GOING INTO MON NIGHT
AND PERHAPS TUESDAY.
FLOW FLATTENS BUT STAYS A LITTLE NWRLY FOR MID WEEK. THIS WILL
MAKE FOR A MAINLY DRY FCST...BUT LITTLE WAVES FLOWING THROUGH THE
FAST FLOW COULD MAKE PRECIP ANY PERIOD. TEMPS DO WARM UP SLOWLY
BUT CONTINUE TO BE BELOW NORMAL FOR MOST OF THE PERIOD.
THEREFORE...LOW CHC/SLIGHT CHC POPS REMAIN IN THE FCST FOR MOST
PERIODS.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
NO SIG CHANGES TO PREVIOUS THINKING FOR THE 18Z SCHEDULED ISSUANCE.
VFR CONDS TO CONTINUE INTO EARLY TONIGHT AS THE AREA REMAINS IN
WARM SECTOR/SE OF SFC LOW TRACKING ENEWD FM THE THUMB OF LWR MI
INTO SRN ONT AND INTO ST LAWRENCE VLY. A COLD FRONT TRAILING THE
LOW WILL REACH NW PA LATE TONIGHT AND BRING SHOWERS TO BFD VCNTY
06-12Z. EXPECT LOWERING CIGS TO REACH THE AREA DURING THIS TIME.
MDL DATA SUPPORTS LOW CIGS/FOG DEVELOPING ACRS THE SERN AIRFIELDS
LATE TNT AS MOIST MARITIME AIR IS ADVECTED NWD/UPSLOPE VIA SELY
LOW LEVEL FLOW.
THE COLD FRONT WILL PUSH FROM WEST TO EAST ACRS LOCAL AIRFIELDS
DURING THE DAY SAT WITH NMRS TO WDSPRD SHOWERS AND ISOLD TSTMS
PSBL OVR THE ERN TERMINALS. WINDS WILL SHIFT FROM SW TO NW-N BY
SAT NGT WITH REDUCED CIGS AND VISBYS EXPANDING TO COVER ALL AREAS.
RAIN WILL LINGER OVR ERN SITES INTO EARLY SUNDAY.
A DEEP UPPER TROUGH AND CUT-OFF LOW IS EXPECTED TO DEVELOP OVR THE
MID ATLC REGION SUN-TUE. THIS WILL BRING AN EXTENDED PD OF POOR
FLYING CONDS AND TEMPS COLD ENUF FOR SNOW. MDL DATA SHOWS A
VIGOROUS COASTAL LOW DEVELOPING OVR THE DELMARVA VCNTY WITH STG
GUSTY NLY WINDS AND RAIN/SNOW PCPN SHIELD EXPANDING/WRAPPING TO
THE N/W OF THE TRACK.
OUTLOOK...
SAT...MVFR/IFR IN RAIN SHOWERS. TSTMS PSBL CENTRAL-EAST.
SUN...VFR/MVFR NW. SHOWERS AND MVFR/IFR EAST.
SUN NGT-TUE...MVFR/IFR LIKELY IN RAIN/SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/STEINBUGL
NEAR TERM...LAMBERT/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DANGELO
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
531 PM CDT THU APR 19 2012
UPDATED FOR 00Z TAF ISSUANCE AND SHORT-TERM FCST UPDATE.
.UPDATE...TRICKY FCST TNGT. RAIN EXPECTED TO CHG TO SNOW ON THE NW
FLANK OF SML BUT FAIRLY INTENSE CYCLONE TRACKING TOWARD THE AREA.
SYSTEM SHOULD REMAIN AN OPEN WAVE...SO THE HEAVIEST PCPN WL FALL
AS THE SFC LOW APPROACHES WITH A SHARP DECR IN INTENSITY ONCE IT
CROSSES JUST S OF THE AREA AND STARTS TO HEAD OFF TO THE E.
CERTAINLY GOING TO GET ENOUGH PCPN TO PRODUCE WARNING CRITERIA
SNOWS...IF IT WAS ALL OR MOSTLY SNOW. PROBLEM IS THE CHANGEOVER.
HAVE WORKED THESE LATE SEASON EVENTS IN THE PAST...AND THE ONE
THING THAT BOTHERS ME RIGHT NOW IS THAT SFC/LOW-LEVEL WET-BULB
TEMPS ARE ALL WELL ABV FZG. MODELS INSIST LOW-LEVEL TEMPS WL COOL
OVERNIGHT...BUT HAVING WET-BULB TEMPS ABV FZG WL LIMIT THE HELP FM
EVAPORATIVE COOLING WHICH CAN OFTEN HELP GET THE CHANGEOVER GOING
AT THIS TIME OF YEAR. MELTING OF THE FALLING SNOW WL PROVIDE SOME
COOLING...BUT CAN/T LOSE TOO MUCH OF THE EVENT TO LIQUID IF FCST
SNOWFALL TOTALS ARE TO WORK OUT.
GOING FCST OKAY FOR NOW...WL CONT TO MONITOR AND PROBABLY MAKE
SOME ADJUSTMENTS LATER THIS EVENING.
RECEIVED ONE REPORT THUS FAR OF A MIX. THAT WAS FM OUT IN WAUPACA
COUNTY ABOUT AN HR AGO. RADAR RETURNS AND RUC MODEL SOUNDINGS
SUGGEST THAT WAS PROBABLY SLEET.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 339 PM CDT THU APR 19 2012...
SHORT TERM...TONIGHT AND FRIDAY. POTENTIAL FOR SIGNIFICANT
SNOWFALL IS THE MAIN CONCERN FOR TONIGHT. THE MODELS...BASED ON
TIME/HEIGHT SECTIONS...HAD SOME SUBSTANTIAL DIFFERENCES IN THEIR
PRECIPITATION TYPE FORECASTS. THE 09Z SREF HAD 0.87 INCHES LIQUID
EQUIVALENT OF SNOW STARTING AROUND 00Z AT RHI WHILE THE 12Z NAM
KEPT IT ALL RAIN WITH ONLY 0.04 TOTAL QPF.
LOW PRESSURE CENTERED AROUND NORTHWEST MISSOURI AT 20Z...IS
FORECAST TO PUSH NORTHEAST AND CROSS SOUTHERN LOWER MICHIGAN ON
FRIDAY. STRONG COLD ADVECTION IS EXPECTED TO CHANGE THE
PRECIPITATION TO SNOW. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF AN UPPER LEVEL JET MAX...ALONG WITH MID LEVEL
SHORT WAVE ENERGY WILL ACT WITH THE LOW TO PRODUCE PLENTY OF
PRECIPITATION. THERE IS ENOUGH MOISTURE ASSOCIATED WITH THE
SYSTEM TO SPREAD WARNING CRITERIA SNOW ACROSS A LARGE PART OF THE
AREA...BUT MUCH OF THE PRECIPITATION WILL HAVE FALLEN BEFORE TEMPERATURES
BECOME COOL ENOUGH FOR SNOW...ESPECIALLY IN THE SOUTHEAST PART OF
THE FORECAST AREA. HAVE KEPT TOTALS IN THE HIGHEST SWATH OF SNOW
BELOW WARNING CRITERIA AS A RESULT OF THIS.
ENDED UP GOING WITH...OR AT LEAST CLOSE TO...THE HPC WINTER
WEATHER ACCUMULATION TOTALS. HAVE OPTED TO KEEP THE ADVISORY AND
ADD WOOD AND PORTAGE COUNTIES FOR HIGHER AMOUNTS IN THE NORTHERN
PARTS OF THOSE COUNTIES.
THE SYSTEM SHOULD MOVE FAIRLY QUICKLY SO ONLY HELD ONTO SOME
CHANCE POPS EARLY FRIDAY MORNING. THIS FORECAST MAY REQUIRE MAJOR
SURGERY SO STAY TUNED FOR FURTHER UPDATES.
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
ZONAL FLOW EARLY IN PERIOD...WILL BECOME AMPLIFIED BY END OF
WEEKEND WITH TROF OVER EASTERN STATES AND OFF WEST COAST AND
RIDGE IN BETWEEN. TEMPERATURES WILL START OUT AT OR SLIGHTLY
BELOW NORMAL AND THEN SHOULD TRANSITION TO ABOVE NORMAL LEVELS BY
THE END OF NEXT WEEK AS UPPER RIDGE SHIFTS EASTWARD.
MID RANGE MODELS SHOWING SIG VARIABILITY WITH SMALLER SCALE/WEAK
FEATURES THROUGH THE EXTENDED. INITIALLY WILL DEAL WITH CLIPPER
TYPE SYSTEM DROPPING OUT OF CANADA...MOVING THROUGH STATE LATER
SAT INTO SUNDAY. TIMING AND STRENGTH VARIABLE. HAVE STAYED WITH
LOWER CHANCE POPS. MODELS STILL SUGGEST SOME STEEP LAPSE RATES
INTO MONDAY WITH CHANCE OF SHOWERS CONTINUING. WAA BEGINS
TUE...AGAIN MERITING LOW POPS. SOME OF THE MODELS SUGGEST
BAROCLINIC ZONE LINGERING OVER NORTHERN WI THROUGH THE LATER PART
OF PERIOD...WITH SOME INSTABILITY PRESENT. AGAIN TIMING IN ISSUE.
RIGHT NOW WILL HIGHLIGHT THU WITH SMALL POPS.
MARINE...LOW MOVING NORTH EAST OUT OF PLAINS THROUGH CHICAGO
REGION WILL BRING INCREASING NE WINDS TO THE AREA. STRONGEST
GRADIENT AND FUNNELING OF WINDS EXPECTED OVER SOUTHERN BAY AND
LAKESHORE SOUTH OF STURGEON BAY. MINIMAL GALE GUST EXPECTED LATE
TONIGHT THROUGH FRI MORNING.
&&
.AVIATION...FOR 00Z TAFS. EXPECT CIGS TO FALL QUICKLY THIS
EVENING...AND SHOULD BE PRIMARILY IN THE LOWER-END VFR OR IFR
RANGE ACRS THE SRN 2/3 OF THE FCST AREA. THE N MAY BE ABLE TO HOLD
UP MORE DUE TO LIGHTER PCPN AND DRY FEED IN FM THE NE. WINDS AT
GRB AND ATW WL REALLY GET GOING LATE THIS EVENING AND OVERNIGHT AS
DIRECTIONAL SHEAR DIMINISHES AND THEY COME ARND THROUGH 040 DEG.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 AM CDT
FRIDAY FOR WIZ013-019>021-030-031-035-036-073-074.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
632 AM CDT THU APR 19 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
338 AM CDT THU APR 19 2012
CHALLENGING FORECAST SETTING UP IN THE VERY SHORT TERM...DEALING
WITH RAIN TODAY AND SOME ACCUMULATING SNOW POSSIBLE TONIGHT.
CURRENT WATER VAPOR IMAGERY SHOWING TROUGH OF LOW PRESSURE PUSHING
EAST OF THE ROCKIES INTO THE HIGH PLAINS. AT THE SURFACE...A WEAK
WAVE OF LOW PRESSURE WAS OVER THE PLAINS WITH A NEARLY STATIONARY
FRONTAL EXTENDING EAST ACROSS SOUTHERN IA INTO NORTHERN IL. RADAR
MOSAIC SHOWING PESKY ON/OFF SHOWERS/ISOLD THUNDER ALONG THIS FRONTAL
BOUNDARY ACROSS SOUTHEAST IA/NORTHERN IL WHERE ISENTROPIC
LIFT/MOISTURE TRANSPORT WAS IMPINGING ON THE FRONTAL BOUNDARY.
LARGER/MORE WIDESPREAD AREA OF RAIN WAS PUSHING EAST OUT OF THE
DAKOTAS INTO WESTERN MN. OTHERWISE...SKIES WERE PARTLY CLOUDY ACROSS
THE LOCAL AREA WITH TEMPERATURES MOSTLY IN THE 40S.
19.00Z NCEP ALONG WITH THE GEM/EURO MODELS IN VERY GOOD AGREEMENT IN
THE SHORT TERM.
WILL SEE THE LOW OVER THE PLAINS LIFT NORTHEAST INTO SOUTHERN IA
EARLY THIS EVENING...AND THEN INTO SOUTHWEST LOWER MI BY FRIDAY
MORNING. INCREASING 925-850MB MOISTURE TRANSPORT ALONG WITH
ISENTROPIC UPGLIDE WILL SPREAD RAIN INTO THE AREA TODAY. X-SECTION
ANALYSIS INDICATES STRONG SURFACE TO 700MB FRONTOGENESIS TAKING
PLACE ACROSS THE AREA FOR FOCUSING MECHANISM OF MODERATE RAINFALL...
WITH PERHAPS SOME EMBEDDED THUNDER SOUTH OF I-90. RAIN MAY BE A BIT
SLOW TO MOVE IN THIS MORNING DUE TO RESIDUAL DRYNESS IN LOWER LAYERS
OF THE ATMOSPHERE...BUT THROUGH THE LATE MORNING-AFTERNOON RAIN WILL
MAKE UP FOR LOST TIME WITH HIGH POTENTIAL FOR 1/2 TO 3/4 INCH
AMOUNTS SOUTH OF I-94. WINDS WILL ALSO BE ON THE INCREASE TODAY FROM
THE EAST/NORTHEAST SETTING UP FOR A RAW DAY OVERALL AS TEMPERATURES
ONLY TOP OFF IN THE MID 40S TO PERHAPS SOME MID 50S ACROSS PORTIONS
OF NORTHEAST IA INTO FAR SOUTHWEST WI.
THINGS GET A BIT INTERESTING TONIGHT AS THE LOW MOVES ACROSS
NORTHERN IL. STRONG FRONTOGENETIC AREA IS MAINTAINED ACROSS THE AREA
FOR MODERATE RAINFALL EARLY IN THE EVENING...BUT THEN STRONG DYNAMIC
COOLING INDICATED BY THE MODELS IS EXPECTED IN THE DEFORMATION AREA
OF THE LOW, THIS WILL CAUSE A RAIN/SNOW MIX FOR AREAS NORTH OF I-90
LATER THIS EVENING...WITH ALL SNOW EXPECTED AFTER MIDNIGHT FOR AREAS
ALONG/NORTH OF I-94. LATEST THINKING IS FOR A SLUSHY 1/2 INCH
POSSIBLE NORTH OF THE WISCONSIN RIVER AND EAST OF THE MISSISSIPPI
RIVER...WITH 1-2 INCHES OF SNOWFALL EAST OF A MAUSTON/BLACK RIVER
FALLS/NEILLSVILLE LINE...AND POSSIBLY HEAVIER AMOUNTS INTO NORTHEAST
WI. THE LOW WILL PULL NORTHEAST TOWARD LAKE HURON FRIDAY
MORNING...PULLING THE BULK OF THE DEFORMATION PRECIPITATION WITH IT.
COULD SEE SOME LINGERING PRECIPITATION EAST OF A SPARTA WI TO
OELWEIN IA LINE. THE REST OF FRIDAY LOOKS DRY WITH A SLOW CLEARING
TREND FROM NORTHWEST TO SOUTHEAST. TEMPERATURES EXPECTED TO BE COOL
AS WELL WITH HIGHS IN THE UPPER 40S TO LOWER 50S.
MOSTLY CLEAR SKIES AND LIGHT/CALM WINDS FRIDAY NIGHT WILL SET UP
IDEAL CONDITIONS FOR TEMPERATURES TO FALL INTO THE UPPER 20S TO
LOWER 30S AND MAY LEAD TO THE NEED FOR FROST/FREEZE HEADLINES. WILL
CONTINUE TO MONITOR THIS.
ON SATURDAY...MODELS SHOW LOW PRESSURE DROPPING SOUTHEAST OUT OF ND
INTO MN. WING OF WARM AIR ADVECTION AND SO-SO MOISTURE TRANSPORT
AHEAD OF THE LOW WILL SPREAD A CHANCE OF -SHRA INTO THE AREA. LOOK
FOR THE LOW TO TRACK EAST INTO WI SATURDAY NIGHT...CONTINUING THE
-SHRA CHANCES. HIGHS SATURDAY WITH INCREASING CLOUD COVER AND RAIN
EXPECTED TO TOP OFF IN THE 50S WITH LOWS SATURDAY NIGHT IN THE
MIDDLE/UPPER 30S.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
338 AM CDT THU APR 19 2012
19.00Z GFS/ECMWF IN REASONABLY GOOD AGREEMENT THROUGH MONDAY...THEN
DIVERGE A BIT TUESDAY/WEDNESDAY TIME FRAME. WENT WITH A MODEL
CONSENSUS IN THIS TIME FRAME. BOTH MODELS SHOW NORTHWEST FLOW ALOFT
LINGERING OVER THE AREA WITH RIDGING OVER THE WESTERN CONUS. THIS
ALLOWS A WEAK MID-LEVEL TROUGH TO ROTATE SOUTHEAST ACROSS THE AREA
FOR A CONTINUED CHANCE OF -SHRA WITH HIGHS ONCE AGAIN IN THE 50S.
THEN FOR TUESDAY THROUGH WEDNESDAY...WARM ADVECTION PATTERN SETS UP
OVER THE REGION AS LOW PRESSURE MOVES ACROSS THE NORTHERN
PLAINS/SOUTHERN CANADA. THIS WILL BRING WARMER TEMPERATURES BUT ALSO
A SMALL CHANCE FOR SHOWERS AND THUNDERSTORMS BOTH DAYS. LOOK FOR
HIGHS TUESDAY IN THE 60S...CLIMBING INTO THE UPPER 60S-MID 70S BY
WEDNESDAY.
&&
.AVIATION...TODAY AND TONIGHT
632 AM CDT THU APR 19 2012
DETERIORATING CONDITIONS TO OCCUR AT THE REGIONAL TAF SITES TODAY
AS A LOW PRESSURE SYSTEM TRACKS ACROSS IOWA. RAIN SHOWERS AND
LOWERING CEILINGS WILL ADVANCE IN FROM THE WEST THIS MORNING AND
AFTERNOON AHEAD OF THE SYSTEM...BUT ANY THUNDERSTORMS SHOULD STAY
SOUTH OF RST/LSE. CONFIDENCE IS NOT THE HIGHEST WITH THE START UP
TIME OF THE RAIN SHOWERS AND HOW SOON AFTERWARD THE CONDITIONS
WILL GO MVFR/IFR. HOWEER...WITH LITTLE IN THE WAY OF SUB-VFR
CONDITIONS CURRENTLY OUT THERE ACROSS SOUTHERN MINNESOTA AND
19.04Z RUC SOUNDINGS SHOWING LOW LEVEL MOISTURE INCREASE THIS
AFTERNOON...HAVE GONE WITH THE INITIAL DROPS TO MVFR EARLY THIS
AFTERNOON WITH IFR CONDITIONS LIKELY SETTING IN WITHIN A FEW HOURS
OF THOSE MVFR DROPS. RAIN WILL BECOME HEAVIER LATE IN THE
AFTERNOON AND EVENING HOURS BEFORE POSSIBLY CHANGING OVER TO
AND/OR MIXING WITH SNOW. 19.06Z AND 19.00Z NAM/GFS BUFKIT
SOUNDINGS SHOW THIS TRANSITION HAPPENING AT RST AROUND 4Z AND AT
LSE AROUND 6Z AND LIKELY LASTING FOR ABOUT 5 HOURS OR SO.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
338 AM CDT THU APR 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
338 AM CDT THU APR 19 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
338 AM CDT THU APR 19 2012
CHALLENGING FORECAST SETTING UP IN THE VERY SHORT TERM...DEALING
WITH RAIN TODAY AND SOME ACCUMULATING SNOW POSSIBLE TONIGHT.
CURRENT WATER VAPOR IMAGERY SHOWING TROUGH OF LOW PRESSURE PUSHING
EAST OF THE ROCKIES INTO THE HIGH PLAINS. AT THE SURFACE...A WEAK
WAVE OF LOW PRESSURE WAS OVER THE PLAINS WITH A NEARLY STATIONARY
FRONTAL EXTENDING EAST ACROSS SOUTHERN IA INTO NORTHERN IL. RADAR
MOSAIC SHOWING PESKY ON/OFF SHOWERS/ISOLD THUNDER ALONG THIS FRONTAL
BOUNDARY ACROSS SOUTHEAST IA/NORTHERN IL WHERE ISENTROPIC
LIFT/MOISTURE TRANSPORT WAS IMPINGING ON THE FRONTAL BOUNDARY.
LARGER/MORE WIDESPREAD AREA OF RAIN WAS PUSHING EAST OUT OF THE
DAKOTAS INTO WESTERN MN. OTHERWISE...SKIES WERE PARTLY CLOUDY ACROSS
THE LOCAL AREA WITH TEMPERATURES MOSTLY IN THE 40S.
19.00Z NCEP ALONG WITH THE GEM/EURO MODELS IN VERY GOOD AGREEMENT IN
THE SHORT TERM.
WILL SEE THE LOW OVER THE PLAINS LIFT NORTHEAST INTO SOUTHERN IA
EARLY THIS EVENING...AND THEN INTO SOUTHWEST LOWER MI BY FRIDAY
MORNING. INCREASING 925-850MB MOISTURE TRANSPORT ALONG WITH
ISENTROPIC UPGLIDE WILL SPREAD RAIN INTO THE AREA TODAY. X-SECTION
ANALYSIS INDICATES STRONG SURFACE TO 700MB FRONTOGENESIS TAKING
PLACE ACROSS THE AREA FOR FOCUSING MECHANISM OF MODERATE RAINFALL...
WITH PERHAPS SOME EMBEDDED THUNDER SOUTH OF I-90. RAIN MAY BE A BIT
SLOW TO MOVE IN THIS MORNING DUE TO RESIDUAL DRYNESS IN LOWER LAYERS
OF THE ATMOSPHERE...BUT THROUGH THE LATE MORNING-AFTERNOON RAIN WILL
MAKE UP FOR LOST TIME WITH HIGH POTENTIAL FOR 1/2 TO 3/4 INCH
AMOUNTS SOUTH OF I-94. WINDS WILL ALSO BE ON THE INCREASE TODAY FROM
THE EAST/NORTHEAST SETTING UP FOR A RAW DAY OVERALL AS TEMPERATURES
ONLY TOP OFF IN THE MID 40S TO PERHAPS SOME MID 50S ACROSS PORTIONS
OF NORTHEAST IA INTO FAR SOUTHWEST WI.
THINGS GET A BIT INTERESTING TONIGHT AS THE LOW MOVES ACROSS
NORTHERN IL. STRONG FRONTOGENETIC AREA IS MAINTAINED ACROSS THE AREA
FOR MODERATE RAINFALL EARLY IN THE EVENING...BUT THEN STRONG DYNAMIC
COOLING INDICATED BY THE MODELS IS EXPECTED IN THE DEFORMATION AREA
OF THE LOW, THIS WILL CAUSE A RAIN/SNOW MIX FOR AREAS NORTH OF I-90
LATER THIS EVENING...WITH ALL SNOW EXPECTED AFTER MIDNIGHT FOR AREAS
ALONG/NORTH OF I-94. LATEST THINKING IS FOR A SLUSHY 1/2 INCH
POSSIBLE NORTH OF THE WISCONSIN RIVER AND EAST OF THE MISSISSIPPI
RIVER...WITH 1-2 INCHES OF SNOWFALL EAST OF A MAUSTON/BLACK RIVER
FALLS/NEILLSVILLE LINE...AND POSSIBLY HEAVIER AMOUNTS INTO NORTHEAST
WI. THE LOW WILL PULL NORTHEAST TOWARD LAKE HURON FRIDAY
MORNING...PULLING THE BULK OF THE DEFORMATION PRECIPITATION WITH IT.
COULD SEE SOME LINGERING PRECIPITATION EAST OF A SPARTA WI TO
OELWEIN IA LINE. THE REST OF FRIDAY LOOKS DRY WITH A SLOW CLEARING
TREND FROM NORTHWEST TO SOUTHEAST. TEMPERATURES EXPECTED TO BE COOL
AS WELL WITH HIGHS IN THE UPPER 40S TO LOWER 50S.
MOSTLY CLEAR SKIES AND LIGHT/CALM WINDS FRIDAY NIGHT WILL SET UP
IDEAL CONDITIONS FOR TEMPERATURES TO FALL INTO THE UPPER 20S TO
LOWER 30S AND MAY LEAD TO THE NEED FOR FROST/FREEZE HEADLINES. WILL
CONTINUE TO MONITOR THIS.
ON SATURDAY...MODELS SHOW LOW PRESSURE DROPPING SOUTHEAST OUT OF ND
INTO MN. WING OF WARM AIR ADVECTION AND SO-SO MOISTURE TRANSPORT
AHEAD OF THE LOW WILL SPREAD A CHANCE OF -SHRA INTO THE AREA. LOOK
FOR THE LOW TO TRACK EAST INTO WI SATURDAY NIGHT...CONTINUING THE
-SHRA CHANCES. HIGHS SATURDAY WITH INCREASING CLOUD COVER AND RAIN
EXPECTED TO TOP OFF IN THE 50S WITH LOWS SATURDAY NIGHT IN THE
MIDDLE/UPPER 30S.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
338 AM CDT THU APR 19 2012
19.00Z GFS/ECMWF IN REASONABLY GOOD AGREEMENT THROUGH MONDAY...THEN
DIVERGE A BIT TUESDAY/WEDNESDAY TIME FRAME. WENT WITH A MODEL
CONSENSUS IN THIS TIME FRAME. BOTH MODELS SHOW NORTHWEST FLOW ALOFT
LINGERING OVER THE AREA WITH RIDGING OVER THE WESTERN CONUS. THIS
ALLOWS A WEAK MID-LEVEL TROUGH TO ROTATE SOUTHEAST ACROSS THE AREA
FOR A CONTINUED CHANCE OF -SHRA WITH HIGHS ONCE AGAIN IN THE 50S.
THEN FOR TUESDAY THROUGH WEDNESDAY...WARM ADVECTION PATTERN SETS UP
OVER THE REGION AS LOW PRESSURE MOVES ACROSS THE NORTHERN
PLAINS/SOUTHERN CANADA. THIS WILL BRING WARMER TEMPERATURES BUT ALSO
A SMALL CHANCE FOR SHOWERS AND THUNDERSTORMS BOTH DAYS. LOOK FOR
HIGHS TUESDAY IN THE 60S...CLIMBING INTO THE UPPER 60S-MID 70S BY
WEDNESDAY.
&&
.AVIATION...
1115 PM CDT WED APR 18 2012
CLOUDS WILL CONTINUE TO INCREASE OVERNIGHT...WITH LOWERING CIGS BY
LATE THU MORNING/AFTERNOON...AS MOISTURE RIDES ACROSS A WEST-EAST
RUNNING WARM FRONT TO THE SOUTH. A GOOD AMOUNT OF LIFT ALONG AND
NORTH OF THE BOUNDARY WILL ALSO RESULT IN WIDESPREAD RA FOR THE
AFTERNOON INTO THE EVENING HOURS. BUFKIT SOUNDINGS SUGGEST AN
EXTENDED PERIOD OF IFR/MVFR CIGS FOR KRST/KLSE DURING THIS TIME.
IN ADDITION...VSBYS AROUND 2SM ALSO LOOK PROBABLE. LITTLE INSTABILTY
INDICATED AND FEEL THE TS THREAT IS LOW AT THIS TIME...SO WILL
CONTINUE TO LEAVE OUT OF THE TAFS.
LATEST HRRR AND NAM12 HAVE SLOWED THE ONSET OF THE RAIN BY A FEW
HOURS...AND HAVE ADJUSTED TIMING IN THE TAFS TO REFLECT THIS.
THE PRESSURE GRADIENT WILL ALSO TIGHTEN AS A LOW TRACKS WEST-EAST
ACROSS THE MID MISSISSIPPI RIVER VALLEY. SO...AFTER A BREAK FROM THE
BREEZY CONDITIONS TONIGHT...LOOK FOR INCREASING WINDS THU...FROM THE
EAST TO NORTHEAST. STRONGEST WINDS LOOK TO BE IN A 22-06Z TIME
FRAME. THERE COULD BE SOME GUSTS...ESPECIALLY AT KRST...BUT
CONFIDENCE NOT HIGH ENOUGH TO INCLUDE QUITE YET.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
338 AM CDT THU APR 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1115 PM CDT WED APR 18 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
307 PM CDT WED APR 18 2012
MAIN FORECAST CONCERNS ARE ON RAIN CHANCES THURSDAY THROUGH
FRIDAY...WITH THE POSSIBILITY OF SEEING SOME SNOW THURSDAY NIGHT AS
COOLER...DRIER AIR ADVECTS SOUTHWEST OUT OF THE U.P. AND NORTHERN
WISCONSIN.
LATEST WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH MOVING ACROSS
WESTERN LAKE SUPERIOR AND NORTHERN WISCONSIN. ANOTHER TROUGH WAS
NOTED MOVING INTO THE PACIFIC NORTHWEST...HEADING EAST. THIS FEATURE
WILL BE THE FOCUS FOR OUR NEXT ROUND OF PRECIPITATION STARTING
THURSDAY.
THE COLD FRONT THAT MOVED ACROSS THE REGION TODAY WILL PUSH EAST AND
SOUTH OF THE FORECAST AREA AS WEAK HIGH PRESSURE BUILDS INTO
NORTHERN MINNESOTA THROUGH NORTHERN WISCONSIN. THE FRONT IS EXPECTED
TO STALL ACROSS CENTRAL IOWA INTO NORTHERN ILLINOIS TONIGHT AND ACT
AS A WARM FRONT AS LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS.
THE UPPER LEVEL TROUGH THAT MOVED ACROSS THE PACIFIC
NORTHWEST...WILL MAKE ITS WAY INTO THE WESTERN DAKOTAS LATE TONIGHT
INTO EARLY THURSDAY MORNING. LOOK FOR SHOWERS TO DEVELOP ACROSS MUCH
OF THE FORECAST AREA THURSDAY MORNING AS ISENTROPIC LIFT INCREASES
ON THE 290-300 K SURFACES. IN ADDITION...FORECAST MODEL CROSS
SECTIONS FROM EAST CENTRAL IOWA...NORTHWARD INTO NORTHWEST
WISCONSIN...SHOW A WELL DEFINED BAND OF FRONTOGENESIS DEVELOPING IN
THE 900-650 MB LAYER...WITH A LARGE REGION OF NEGATIVE EPV LOCATED
JUST ABOVE THE FRONTOGENESIS BAND. NEGATIVE EPV VALUES ARE AROUND
-4. WITH THIS MUCH SUPPORT...WOULD EXPECT TO SEE RAIN SHOWERS ACROSS
MUCH OF THE FORECAST AREA...WITH THE HEAVIER RAIN SHOWERS OCCURING
SOUTH OF A LINE FROM WABASHA TO WISCONSIN RAPIDS. IN
ADDITION...PRECIPITABLE WATER VALUES INCREASE TO AROUND 150 TO 200
PERCENT OF NORMAL ALONG AND SOUTH OF INTERSTATE 90 SO WOULD NOT BE
SURPRISED TO SEE RAINFALL TOTALS IN EXCESS OF AN INCH BY THURSDAY
EVENING. THE NAM IS SHOWING A BAND OF SNOW DEVELOPING ACROSS
NORTHWEST INTO NORTH CENTRAL WISCONSIN...WHERE TEMPERATURES MAY BE
COLD ENOUGH FOR SNOW. FEEL THIS BAND IS A BIT OVERDONE SO WILL NOT
ADD SNOW CHANCES TO NORTH CENTRAL WISCONSIN DURING THE DAY ON
THURSDAY BUT THIS WILL BE SOMETHING TO KEEP AN EYE ON.
THE TROUGH IS EXPECTED TO DIG INTO THE CENTRAL PLAINS THURSDAY
NIGHT. AS IT DIGS...COOLER/DRIER AIR WILL WRAP INTO TH FORECAST AREA
FROM THE NORTH/NORTHEAST AS SURFACE LOW PRESSURE MOVES FROM SOUTHERN
IOWA INTO CENTRAL ILLINOIS. DEW POINTS QUICKLY FALL INTO THE MID 20S
TO LOWER 30S...WHICH RAISES THE CONCERN OF EVAPORATIVE COOLING AND
THE POTENTIAL FOR A SWITCH OVER TO SNOW AS THE COOLER DRIER AIR
MOVES IN. FORECAST SOUNDINGS SHOWS MUCH OF THE SATURATION IS BEING
LOST BEFORE THIS AIR MOVES IN...SO OVERALL SNOW CHANCES LOOK
LIMITED. CANNOT RULE OUT SOME SNOW MIXING IN LATE THURSDAY NIGHT
NORTH OF INTERSTATE 90 BEFORE THE SYSTEM EXITS TO THE EAST.
SIGNIFICANT SNOW ACCUMULATIONS ARE NOT EXPECTED AT THIS TIME...BUT
WILL HAVE TO KEEP A CLOSE WATCH ON THE EXACT LOW TRACK AND HOW
QUICKLY COOLER AIR WRAPS INTO THE SYSTEM. FORECAST SOUNDINGS SHOW
SURFACE TEMPERATURES FALLING BELOW FREEZING ALONG AND NORTH OF
INTERSTATE 94 LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING. THESE
AREAS MAY NEED FROST/FREEZE HEADLINES IF TRENDS CONTINUE. COOL HIGH
PRESSURE WILL SETTLE OVER THE AREA ON FRIDAY PROVIDING PARTLY SUNNY
SKIES WITH HIGHS RANGING FROM THE UPPER 40S ACROSS NORTH CENTRAL
WISCONSIN TO THE LOWER 50S ACROSS NORTHEAST IOWA. THE SURFACE RIDGE
WILL BE OVER THE FORECAST AREA FRIDAY NIGHT LEADING TO MOSTLY CLEAR
SKIES COOL OVERNIGHT LOWS. LOW TEMPERATURES ARE EXPECTED TO RANGE
FROM THE UPPER 20S ACROSS NORTH CENTRAL WISCONSIN TO THE MID 30S
ACROSS NORTHEAST IOWA. FROST OR FREEZE HEADLINES MAY BE NEEDED
ACROSS PORTIONS OF SOUTHWEST...CENTRAL INTO NORTH CENTRAL WISCONSIN.
THE HIGH WILL PUSH EAST OF THE FORECAST AREA ON SATURDAY AS A TROUGH
PUSHES EAST ACROSS THE DAKOTAS AND HEADS FOR THE UPPER MISSISSIPPI
RIVER VALLEY. SOME TIMING DIFFERENCES NOTED BETWEEN THE NAM/GFS WITH
THIS FEATURE. THE LATEST NAM IS MUCH FASTER...BRINGING PRECIPITATION
INTO LOCATIONS WEST OF THE MISSISSIPPI RIVER SATURDAY MORNING...THEN
SPREADING WEST OF THE RIVER SATURDAY AFTERNOON. THE GFS HOLD OFF ON
PRECIPITATION UNTIL SATURDAY EVENING AND SHOWS THE MAIN WAVE MOVING
NORTHWEST TO SOUTHEAST ACROSS WESTERN WISCONSIN. THE GFS SCENARIO
WOULD KEEP MOST OF THE PRECIPITATION EAST OF THE MISSISSIPPI RIVER.
THE 00Z ECMWF IS MORE IN LINE WITH THE GFS. THE GEM OFFERS A
DIFFERENT SOLUTION...HOLDING THE BULK OF THE PRECIP WEST OF THE
RIVER. WILL SIDE WITH THE GFS SOLUTIONS SINCE IT HAVE BEEN ONE OF
THEM MORE CONSISTENT MODELS WITH THIS SYSTEM. WILL ADD A SLIGHT
CHANCE OF SHOWERS TO LOCATIONS WEST OF THE MISSISSIPPI
RIVER...SPREADING CHANCES EAST OF THE RIVER DURING THE EVENING AND
OVERNIGHT HOURS.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
307 PM CDT WED APR 18 2012
18.12 FORECAST MODELS ARE IN REASONABLE AGREEMENT ON SUNDAY SHOWING
A BROAD UPPER LEVEL RIDGE BUILDING ACROSS THE WESTERN CONUS AS A
TROUGH DIGS OFF OF THE EAST COAST. MAINLY QUIET CONDITIONS ARE
EXPECTED SUNDAY NIGHT THROUGH TUESDAY WITH HIGH PRESSURE IN CONTROL.
PLAN ON HIGHS ON MONDAY RANGING FORM THE UPPER 50S ACROSS NORTH
CENTRAL WISCONSIN TO THE LOWER 60S ACROSS NORTHEAST IOWA. A FAST
MOVING SHORTWAVE TROUGH THE REGION TUESDAY NIGHT INTO WEDNESDAY AS
THE RIDGE FLATTENS AND SHIFTS EAST. A WARM FRONT IS EXPECTED TO PUSH
ACROSS THE FORECAST AREA DURING THIS TIMEFRAME...BRINGING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE AREA. PLAN ON WARMER
TEMPERATURES ON WEDNESDAY WITH HIGHS CLIMBING INTO THE 70S
&&
.AVIATION...
1115 PM CDT WED APR 18 2012
CLOUDS WILL CONTINUE TO INCREASE OVERNIGHT...WITH LOWERING CIGS BY
LATE THU MORNING/AFTERNOON...AS MOISTURE RIDES ACROSS A WEST-EAST
RUNNING WARM FRONT TO THE SOUTH. A GOOD AMOUNT OF LIFT ALONG AND
NORTH OF THE BOUNDARY WILL ALSO RESULT IN WIDESPREAD RA FOR THE
AFTERNOON INTO THE EVENING HOURS. BUFKIT SOUNDINGS SUGGEST AN
EXTENDED PERIOD OF IFR/MVFR CIGS FOR KRST/KLSE DURING THIS TIME.
IN ADDITION...VSBYS AROUND 2SM ALSO LOOK PROBABLE. LITTLE INSTABILTY
INDICATED AND FEEL THE TS THREAT IS LOW AT THIS TIME...SO WILL
CONTINUE TO LEAVE OUT OF THE TAFS.
LATEST HRRR AND NAM12 HAVE SLOWED THE ONSET OF THE RAIN BY A FEW
HOURS...AND HAVE ADJUSTED TIMING IN THE TAFS TO REFLECT THIS.
THE PRESSURE GRADIENT WILL ALSO TIGHTEN AS A LOW TRACKS WEST-EAST
ACROSS THE MID MISSISSIPPI RIVER VALLEY. SO...AFTER A BREAK FROM THE
BREEZY CONDITIONS TONIGHT...LOOK FOR INCREASING WINDS THU...FROM THE
EAST TO NORTHEAST. STRONGEST WINDS LOOK TO BE IN A 22-06Z TIME
FRAME. THERE COULD BE SOME GUSTS...ESPECIALLY AT KRST...BUT
CONFIDENCE NOT HIGH ENOUGH TO INCLUDE QUITE YET.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
307 PM CDT WED APR 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS MIAMI FL
154 AM EDT SAT APR 21 2012
.AVIATION...
CERTAINLY NEED TO STRESS THE UNCERTAINTY IN THE FORECAST WITH THE
POTENTIAL FOR CONVECTION AND ASSOCIATED THUNDERSTORMS CONTINUING
THROUGH THE EARLY MORNING HOURS. FOR THE SHORT TERM...ASSIGNED
VCTS FOR TERMINAL KAPF WITH THE MOST ACTIVE AREA OF THUNDERSTORMS
REMAINING ACROSS THE LOCAL GULF WATERS. SHOWERS WILL LIKELY
CONTINUE TO AFFECT TERMINAL KAPF THROUGHOUT THE MORNING HOURS WITH
VISIBILITIES REDUCE TO PERHAPS 4 SM TO 5 SM WITH MODERATE SHOWERS
WITH OCCASIONALLY HEAVY SHOWERS POSSIBLE WITH PERIODS OF IFR
CONDITIONS POSSIBLE WITH HEAVY SHOWERS OR A THUNDERSTORM. FOR THE
EAST COAST TAFS,...FOR NOW CONVECTION HAS SUBSIDED WITH VFR
CONDITIONS PREVAILING. HOWEVER...GIVEN THE INSTABILITY ACROSS THE
AREA AND WITH LINGERING BOUNDARIES FROM EARLIER
CONVECTION...SHOWERS AND/OR THUNDERSTORMS COULD HAPPEN AT ANY TIME
WITH BRIEF PERIODS OF IFR CONDITIONS POSSIBLE. BY 12Z SATURDAY A
SURFACE LOW IS FORECAST TO BUILD INTO THE NORTHEAST GULF WHICH
WILL CONTRIBUTE TO THE CONTINUING POTENTIAL FOR CONVECTION AND
THUNDERSTORMS FOR ALL TAF SITES WITH BRIEF PERIODS OF IFR
CONDITIONS POSSIBLE WITH OCCURRENCE OF HEAVY SHOWERS AND THUNDERSTORMS.
60
&&
.PREV DISCUSSION... /ISSUED 1008 PM EDT FRI APR 20 2012/
UPDATE...
SOUTHWEST PROPAGATING OUTFLOW BOUNDARIES FROM EARLIER CONVECTION
ARE SPARKING FURTHER SHOWERS AND THUNDERSTORMS BACK ACROSS
INTERIOR AREAS AND TO THE GULF COAST. LATEST HRRR ALSO DEPICTS
CONVECTION IN THE CENTRAL AND WESTERN GULF OF MEXICO OUT AHEAD OF
THE LARGER H5 LOW TO PUSH ASHORE AROUND 05Z. INCREASED POPS TO
ADJUST FOR CURRENT RADAR TRENDS.
PREV DISCUSSION... /ISSUED 803 PM EDT FRI APR 20 2012/
UPDATE...
SENT UPDATE TO INCREASE POPS ACROSS ALL OF SOUTH FLORIDA THIS
EVENING...ESPECIALLY ACROSS PALM BEACH AND BROWARD COUNTIES AND
ACROSS LAKE OKEECHOBEE. SHOWERS AND THUNDERSTORMS CONTINUE TO PUSH
TO THE EAST BUT ARE ALSO BACK BUILDING. STRONGEST STORMS ARE IN A
WEAKENING PHASE AND SHOULD CONTINUE TO WEAKEN THROUGH THE LATE
EVENING HOURS.
PREV DISCUSSION... /ISSUED 747 PM EDT FRI APR 20 2012/
AVIATION...
ONGOING CONVECTION CONTINUES TO AFFECT EAST COAST TERMINALS WITH
THE EXCEPTION OF KMIA AND KTMB ATTM. ACTIVITY IS SLOWLY PUSHING TO THE
EAST BUT LATEST TRENDS DEPICT CB TOWERS BUILDING BACK TO THE WEST.
CONVECTION SHOULD WEAKEN SOMEWHAT DURING THE OVERNIGHT HOURS
BEFORE ANOTHER WAVE OF SHRAS/TSRAS BEGIN TO PUSH INTO SOUTH
FLORIDA SATURDAY MORNING. ACTIVITY DURING THE DAY ON SATURDAY AND
ESPECIALLY SATURDAY EVENING IS EXPECTED TO BE STRONGER AND MORE
EXTENSIVE.
PREV DISCUSSION... /ISSUED 215 PM EDT FRI APR 20 2012/
STRONG TO SEVERE STORMS POSSIBLE OVER S FLA THIS WEEKEND...
TWO ROUNDS OF THUNDERSTORM ACTIVITY FOR SOUTH FLORIDA...
AMPLIFYING UPPER RIDGE OVER THE RKY MTN CHAIN INTO S CANADA ALLOWING
A DEEPENING TROUGH OVER THE CENTRAL GREAT PLAINS TO PLUNGE INTO THE
LOWER MS RIVER VALLEY WITH A CLOSED LOW DEVELOPING OFF OF THE GULF
COAST DURING THE DAY SATURDAY. THIS CLOSED LOW WILL CONTINUE TO DIVE
SE INTO THE CENTRAL GULF BEFORE LIFTING TO THE NE SATURDAY EVENING
AND CROSSING N FLA SUNDAY MORNING AND THEN NE ALONG THE SE U.S.
COAST SUNDAY AFTERNOON. ANOTHER SHORT WAVE DIVING SE ACROSS THE
GREAT LAKES REGION ABSORBS THE E COAST LOW INTO A CLOSED LOW OVER
THE E OHIO RIVER VALLEY THAT MOVES NORTHWARD INTO S CANADA.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...AS THE UPPER TROUGH
CONTINUES TO DEVELOP...THE S FLA AREA WILL BE UNDER AN INCREASING
AND BECOMING DIVERGENT SW WIND FLOW ALOFT WITH EMBEDDED IMPULSES
GENERATING CONVECTION. THE DIURNAL CONVECTION TODAY WILL LINGER INTO
THE EVENING HOURS MAINLY NE BUT DEVELOPING ACTIVITY OVER THE S
CENTRAL GULF WILL SPREAD NE AND ONTO THE W COAST LATE TONIGHT AND
SPREAD ACROSS S FLA TO THE E COAST BY SATURDAY MORNING. ACTIVITY
COULD GET ACTIVE ESPECIALLY ON THE W COAST BUT WEAKEN SOME UPON
REACHING THE E COAST. WITH CLOUD COVER AND A SLIGHTLY MORE STABLE
ATMOSPHERE EARLY SATURDAY...HEAVY CONVECTION MAY BE LIMITED DURING
THE DAY BUT A LITTLE HEATING IN THE MOIST ATMOSPHERE ( BECOMING 2
STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR ) WITH
POSSIBLE LAKE/SEA BREEZES...SHOWER/THUNDERSTORM ACTIVITY CAN AGAIN
BE EXPECTED. WITH THE INCREASED MOISTURE IN THE ATMOSPHERE
POSSIBLE TRAINING OF ECHOES...LOCALLY HEAVY RAINS...WILL NOT BE
OUT OF THE QUESTION ESPECIALLY W. LATE SATURDAY AFTERNOON AND INTO
SATURDAY NIGHT....IT APPEARS THAT THE STRONGEST IMPULSE WILL MOVE
OVER S FLA. STRONG STORMS CAN BE EXPECTED TO DEVELOP IN THE GULF AND
ACROSS S FLA WITH EVEN SEVERE STORMS POSSIBLE. THE MAIN THREAT IS
EXPECTED TO BE DAMAGING WINDS BUT ISOLATED TORNADOES AND LARGE HAIL
ARE ALSO POSSIBLE. DECREASING CONVECTION EXPECTED SUNDAY WITH ALL
ACTIVITY ENDING SUNDAY NIGHT. UNCERTAINTY STILL EXISTS AS THE MODELS
HAVE BEEN WAFFLING ON THE TIMING BUT THIS IS THE CURRENT THINKING.
RESIDENTS AND VISITORS IN SOUTH FLORIDA ARE URGED TO KEEP ABREAST OF
THE LOCAL FORECAST AS THIS WEATHER SITUATION CONTINUES TO UNFOLD.
EXTENDED PERIOD...MONDAY THROUGH FRIDAY...A DRY NW WIND FLOW WILL
BE OVER S FLA THROUGH THE PERIOD WITH NO PRECIPITATION EXPECTED.
MAX/MIN TEMPS A BIT BELOW NORMAL FOR A COUPLE OF DAYS THEN A SLOW
WARMING REND TOWARD THE END OF THE WEEK.
MARINE...MARINE CONDITIONS REALLY BEGIN TO DETERIORATE AHEAD OF THE
APPROACHING LOW/FRONT SATURDAY AFTERNOON WITH WINDS INCREASING ABOVE
ADVISORY CRITERIA POSSIBLY AS EARLY AS SATURDAY NIGHT. THE INCREAS
-ING SW WIND FLOW WILL LEAD TO AN INCREASE IN THE RISK OF RIP
CURRENTS AND ROUGH SURF ALONG THE WEST COAST OF S FLA BEGINNING AS
EARLY AS SATURDAY AFTERNOON. SOME COASTAL FLOODING ALONG THE W
COAST OF S FLA WILL ALSO BE POSSIBLE. WATER LEVELS MAY REACH 1 TO 2
FT ABOVE THE REGULAR HIGH TIDE FROM LATE SATURDAY AFTERNOON THROUGH
SUNDAY AFTERNOON ANYWHERE FROM MARCO ISLAND TO EVERGLADES CITY. ANY
AREAS TYPICALLY VULNERABLE TO MINOR COASTAL FLOODING SHOULD CONTINUE
TO MONITOR THE LATEST FORECASTS AS THIS GULF LOW PRESSURE SYSTEM
DEVELOPS AND TRACKS EAST OVER THE FL PENINSULA.
FIRE WEATHER...NO CONCERNS AT THIS TIME BUT MUCH DRIER CONDITIONS
ARE EXPECTED TO SPREAD ACROSS S FLA EARLY NEXT WEEK WITH RH FALLING
AT OR BELOW 35%.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 70 85 65 / 80 70 50 20
FORT LAUDERDALE 82 71 86 67 / 80 70 50 20
MIAMI 83 70 85 67 / 80 70 50 20
NAPLES 82 69 81 66 / 80 70 50 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...47/RGH
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
205 AM EDT SAT APR 21 2012
.SYNOPSIS...
A COLD FRONT IS CROSSING THE REGION TONIGHT...BRINGING A PERIOD OF
SHOWERS...THEN COOLER TEMPERATURES FOR SATURDAY. HIGH PRESSURE ACROSS
EASTERN CANADA WILL BRING DRY BUT COOL CONDITIONS SUNDAY. THEN
STRENGTHENING LOW PRESSURE IN THE MID ATLANTIC WILL CIRCLE BACK
INTO NEW YORK MONDAY WHICH WILL RESULT IN A SOAKING RAIN AND
POSSIBLY SOME SNOW.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK LOW PRESSURE SHIFTING EAST ACROSS LAKE ONTARIO WITH A COLD
FRONT NOW CROSSING WESTERN NEW YORK. THERE IS A CHANCE FOR A SHOWER
AHEAD OF AND ALONG THE FRONT BUT THE STEADIEST RAIN SHOULD ARRIVE
POST-FRONTAL AFTER MIDNIGHT INTO SATURDAY MORNING.
HAVE OBSERVED A FEW STRIKES OF LIGHTNING EARLIER THIS EVENING IN WEAKLY
CONVECTIVE CELLS ALONG THE LEADING EDGE OF THE FRONT. DUE TO
THIS...SLIGHT CHANCE FOR THUNDER REMAINS IN THE WEATHER GRIDS
THROUGH AROUND 05Z. THE REGIONAL RADAR MOSAIC SHOWS THE STEADIER
SHOWERS ARE BEHIND THE COLD FRONT MOVING ACROSS SOUTHERN ONTARIO AND
OHIO. THE POST FRONTAL SHOWERS ARE LIKELY THE RESULT OF LIFT ALOFT
GENERATED BY THE UPPER TROF OVER THE CENTRAL US.
THE 00Z HRRR MODEL SHOWS STEADY RAIN ARRIVING IN NIAGARA
FRONTIER/WESTERN SOUTHERN TIER AROUND 2AM...GENESEE VALLEY AROUND
4AM AND WATERTOWN SOUTH THROUGH CENTRAL NY AROUND 8AM. MOST AREAS
WILL SEE A FEW HOURS OF RAIN WITH AN AREA AVERAGE QPF OF .10 TO .25
INCHES.
LOWS WILL RANGE FROM THE 40S WEST...TO THE LOWER 50S EAST. A DECENT
SOUTHERLY FLOW EXISTS EAST AND SOUTHEAST OF LAKE ONTARIO THIS
EVENING...WITH HIGHER TERRAIN ON THE TUG HILL AND VALLEYS FAVORABLE
TO FUNNELING LIKELY TO SEE GUSTS OF 20 TO 30 MPH.
THE FRONT WILL SLOWLY EXIT TO THE EAST ON SATURDAY...WITH SHOWERS
EXPECTED TO GRADUALLY TAPER OFF. NOT TO OPTIMISTIC ABOUT A
CLEARING DURING THE DAY...GIVEN THE SLOW MOVEMENT OF THE
FRONT...HOWEVER FAR WESTERN PORTIONS MAY SEE A FEW BREAKS OF SUN
LATE SATURDAY AFTERNOON. CLOUDS WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 40S TO LOWER 50S ACROSS WESTERN NEW YORK...NOTABLY COOLER THAN
THE PAST FEW DAYS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
HIGH PRESSURE BRIEFLY NOSES SOUTHWARD FROM EASTERN ONTARIO ON
SATURDAY NIGHT WITH SKIES CLEARING FROM WEST TO EAST. COOLER AND
DRIER AIR WITH THE CLEARING SKIES WILL ALLOW TEMPS TO FALL TO THE
LOWER 30S ACROSS THE SOUTHERN TIER AND TUG HILL REGION.
THE REGION WILL SEE A PARTLY TO MOSTLY SUNNY START TO SUNDAY WITH
CHILLY MORNING TEMPS RISING TO THE MID 40S TO AROUND 50 DEGREES BY
MID AFTERNOON. THERE WILL BE AN INCREASE IN CLOUDINESS AS A STRONG
STORM SYSTEM LIFTS NORTHWARD FROM THE MID ATLANTIC.
DEEPENING LOW PRESSURE MOVES UP THE MID ATLANTIC COAST AND
RETROGRESSES TO NEW YORK STATE ON MONDAY. THIS IS WELL DEPICTED BY
GFS AND ECMWF...THE EC IS JUST A LITTLE SLOWER THAN GFS...BUT THE
RESULT IS ABOUT THE SAME.
TO PUT THIS INTO SOME PERSPECTIVE...THIS PATTERN IS ALMOST A FRAME
BY FRAME REPLAY OF AN EVENT WHICH OCCURRED ON THE 2ND AND 3RD OF
APRIL 2005. THERE WAS AN 8 INCH SNOWFALL AT KBUF WITH MORE THAN A
FOOT OF SNOW ALONG THE CHAUTAUQUA RIDGE...AND EVEN TWO FEET OF SNOW
ACROSS NORTHWESTERN PA AND NORTHEAST OHIO.
THE CURRENT GFS AND ECMWF INDICATE THE POTENTIAL FOR SIMILAR AMOUNT
OF SNOW IN VERY SIMILAR LOCATIONS. GLANCING AT A COMPARISON OF THE
2005 EVENT AND CURRENT BUFKIT SOUNDINGS...THE VERTICAL TEMP/DEWPOINT
PROFILE IS NEARLY EXACT WITH THE CURRENT DATA SHOWING EVEN MORE
MOISTURE ALOFT. THE 2005 EVENT HAD PRECIPITABLE WATER RANGING FROM
.45 INCH TO .55 INCH...THE CURRENT DATA SHOW PWS AT OR ABOVE .75
INCH. ADDITIONALLY...THE 850MB TEMPS ARE COLDER BY A DEGREE OR TWO
SOUTH OF BUFFALO TO WESTERN PENNSYLVANIA.
SPEAKING OF MOISTURE...THERE WILL BE SIGNIFICANT MOISTURE WRAPPED
ABOUT THIS STORM...QPF FOR CENTRAL NY THROUGH MONDAY EVENING WILL BE
ON THE ORDER OF 2.5 INCHES WITH 1.75 TO 2.00 INCHES ACROSS WESTERN
NY. THE TRANSITION FROM RAIN TO SNOW WILL BE SOMEWHERE BETWEEN SYR
AND ROC SOUTHWARD ALONG SENECA AND CAYUGA LAKES. THE HEAVIEST SNOW
WILL LIKELY BE CENTERED ACROSS ALLEGANY/WYOMING/CATTARAUGUS COUNTIES
WITH SNOW TOTAL EXCEEDING A FOOT...ENHANCED BY NORTHEASTERLY TO
NORTHERN WINDS AND THE UPLIFT ALONG THE WESTERN SLOPE OF THE GENESEE
VALLEY.
EXPECT RAIN ALONG THE SOUTH SHORE OF LAKE ONTARIO AND ACROSS CENTRAL
TO NORTHERN NY. THE NEAR DROUGHT CONDITIONS OF LATE WILL ABSORB THE
RAINFALL AS LONG AS IT IS NOT TOO MUCH TOO FAST...THEN THERE MAY BE
A RISK OF LOW IMPACT AND SHORT LIVED FLOODING.
IN TERMS OF HOW POTENTIALLY UNUSUAL THIS WHOLE EVENT COULD BE (ESP
THE SNOW ASPECT OF IT)...NEARLY ALL OF THE MAJOR FORECAST PARAMETERS
(H5/7 HGHTS...MSLP...H85 TEMPS...U AND V WIND COMPONENTS) ARE 4 TO 5
STANDARD DEVIATIONS FROM NORMAL. IT IS CERTAINLY SIGNIFICANT WHEN A
COUPLE FORECAST PARAMETERS ARE THAT ANOMALOUS...BUT WHEN NEARLY ALL
OF THE MAIN FACTORS ARE THIS FAR FROM NORMAL...THEN THE EVENT STARTS
TO RISE TO THAT OF A MEMORABLE OR EVEN HISTORIC STATURE. THAT BEING
SAID...THESE PARAMETERS HAVE TO COME TOGETHER IN THE PERFECT MIX AND
THAT IS STILL FAR FROM A CERTAINTY.
TEMPS SUNDAY NIGHT WILL ONCE AGAIN BE QUITE CHILLY WITH CONTINUED
NORTHERLY WINDS...MID 30S ALONG THE LAKESHORES AND THE NORTH
COUNTRY...AND UPPER 20S TO AROUND 30 DEGREES FOR THE GENESEE VALLEY
AND WESTERN SOUTHERN TIER WHERE DYNAMIC COOLING FROM THE ONSET OF
SNOW WILL LOWER TEMPS EVEN FURTHER.
THICK CLOUD COVER AND PRECIP WILL HOLD TEMPS DOWN DURING MONDAY.
EXPECT THE WARMER TEMPS IN THE UPPER 40S TO LOWER 50S ACROSS THE
NORTH COUNTRY AND CENTRAL NY CLOSER TO THE CENTER OF THE LOW
PRESSURE. COLDER TEMPS ARE EXPECTED FOR THE WEST AND ESPECIALLY
SOUTHERN COUNTIES WITH LOWER 40S ALONG THE LAKESHORES AND THE 30S
FOR THE GENESEE VALLEY AND SOUTHERN TIER...IN THE REGION OF
CONTINUED LIKELIHOOD OF SNOWFALL.
THE POPS WILL FALL FROM WEST TO EAST ON MONDAY NIGHT AS THE LOW
PRESSURE CENTER LIFT NORTHWARD INTO QUEBEC PROVINCE...BUT WILL
REMAIN AS A CHANCE OF SNOW OR A MIX OF RAIN AND SNOW. LOWS WILL BE
IN THE UPPER 20S TO LOWER 30S ACROSS WESTERN AND SOUTHERN NY WITH
LOWER TO MID 30S ELSEWHERE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
GFS AND ECMWF REMAIN IN FAIR AGREEMENT FOR MUCH OF THE REST OF THE
WEEK. WILL KEEP LOW CHANCE POPS IN FOR TUESDAY AS THE REMAINS OF THE
PREVIOUS STORM MOVE AWAY FROM THE REGION...AND CHANCE POPS THROUGH
THURSDAY AFTERNOON AS THE UPPER TROUGH OVER EASTERN CANADA STREAMS A
SERIES OF VORTICITY MAXIMA ACROSS THE GREAT LAKES REGION AND INTO
NEW YORK STATE.
TEMPS WILL MODERATE THROUGH THE REST OF THE WEEK WITH HIGHS ON
TUESDAY IN THE UPPER 30S AND LOWER 40S CLIMBING TO HIGHS IN THE MID
50S TO NEAR 60 ON FRIDAY. OVERNIGHT LOWS WILL STILL SHOW LOCAL
FLIRTATIONS WITH THE FREEZING MARK FOR THE INTERIOR COUNTIES...WITH
MID TO UPPER 30S ELSEWHERE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT IS CURRENTLY IN THE PROCESS OF CROSSING THE FORECAST
AREA WITH THE FRONTAL BOUNDARY CLEARLY DEMARCATED ALONG A LINE
RUNNING FROM KART TO BETWEEN KBFD/KJHW. WINDS ARE QUICKLY VEERING
FROM SOUTHERLY JUST AHEAD OF THE FRONT TO NORTHWESTERLY BEHIND THE
BOUNDARY. A SLOW MOVING BAND OF SHOWERS BEHIND THE FRONT IS CROSSING
LAKE ERIE AND THE NIAGARA PENINSULA AND WILL BE MOVING INTO FAR
WESTERN NEW YORK WITHIN THE NEXT COUPLE OF HOURS. CIGS WILL DROP
INTO MVFR TERRITORY WITH IFR POSSIBLE PARTICULARLY AT KJHW WHERE
UPSLOPE FLOW WILL AID IN LOWERING CIGS.
THIS BAND OF SHOWERS WILL SLOWLY MOVE EAST THROUGH THE REST OF THE
NIGHT AND INTO SATURDAY MORNING...ARRIVING AT KART BY AROUND 12Z.
PRECIP WILL TAPER OFF ACROSS FAR WESTERN NEW YORK BY LATE
MORNING...THOUGH MVFR CIGS WILL LIKELY HANG AROUND UNTIL
APPROXIMATELY 00Z. THE IMPROVING CONDITIONS WILL GRADUALLY WORK
THEIR WAY EAST WHILE IMPROVING TO VFR SATURDAY NIGHT.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...MAINLY VFR.
SUNDAY NIGHT...LOWERING TO MVFR IN LIKELY SHOWERS.
MONDAY...IFR/MVFR. RAIN OR SNOW LIKELY.
TUESDAY THROUGH THURSDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
A COLD FRONT WILL SLOWLY CROSS THE EASTERN LAKES TONIGHT. A DECENT
SOUTHERLY FLOW AHEAD OF THE FRONT HAS ALLOWED A FEW GUSTS TO 20KTS
ON EASTERN PORTIONS OF LAKE ONTARIO THIS EVENING WHICH ARE MARGINAL
SUB-SMALL CRAFT CRITERIA. WINDS WILL NOT BE STRONG BEHIND THE FRONT.
THE FRONT WILL SHIFT EAST SATURDAY MORNING WITH NO ANTICIPATED
MARINE IMPACTS EXPECTED SATURDAY AND SUNDAY.
STRONG LOW PRESSURE WILL DEVELOP IN THE MID ATLANTIC REGION SUNDAY
NIGHT...WITH AN INCREASING NE-N FLOW ON THE WATERS. THIS WILL LIKELY
RESULT IN SOME FLAGS ON THE WATERS...WITH GALES A GOOD
POSSIBILITY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...SMITH
SHORT TERM...RSH/WCH
LONG TERM...WCH
AVIATION...WOOD
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 AM CDT SAT APR 21 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
342 AM CDT SAT APR 21 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES TODAY THROUGH
SUNDAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ACROSS MUCH OF THE WESTERN U.S....TROUGHING
ENCOMPASSING MUCH OF THE WESTERN GREAT LAKES REGION...AND AN UPPER
LOW NEAR THE SOUTHWEST LOUISIANA COAST. COMING INTO THE UPPER
TROUGHING WAS A SHORTWAVE OVER NORTHERN NORTH DAKOTA. A LARGE AMOUNT
OF MID AND HIGH CLOUDS WERE PRESENT AHEAD OF THE SHORTWAVE...
STREAMING INTO THE WESTERN PART OF THE FORECAST AREA. RADAR AND
SURFACE OBS SHOW SHOWERS OCCURRING ACROSS EASTERN NORTH DAKOTA...IN
AN AREA OF DPVA AHEAD OF THE SHORTWAVE...WARM ADVECTION NOTED BY
SOUTHWEST WINDS OF 20-25 KT AT 850MB ON ABR AND FGF RADARS...AND
UPPER DIVERGENCE IN THE LEFT EXIT REGION OF A 100 KT JET STREAK OVER
SOUTH DAKOTA. RUC CROSS-SECTIONS SHOW A NICE LOW TO MID-LEVEL
FRONTOGENESIS ZONE THERE TOO WITH A FRONTOLYSIS/FRONTOGENESIS
COUPLET. PRECIPITABLE WATER UP IN EASTERN NORTH DAKOTA AROUND 0.5
INCH PER 00Z SOUNDINGS FROM BIS AND ABR. CLOSER TO THE FORECAST
AREA...A SURFACE HIGH PRESSURE RIDGE IS IN PLACE. MAINLY CLEAR SKIES
UNTIL RECENTLY COMBINED WITH DRY AIR NOTED BY PRECIPITABLE WATER OF
0.24 INCHES ON THE 00Z GRB SOUNDING HAS ALLOWED TEMPERATURES TO DROP
INTO MOSTLY THE 30S...COLDEST OVER CENTRAL WISCONSIN WHERE A FEW
UPPER 20S HAVE OCCURRED.
REGARDING CURRENT FROST/FREEZE HEADLINES...HAVE DROPPED THE FROST
ADVISORY AS CLOUDS SEEM TO BE HAMPERING TEMPS FROM DROPPING ENOUGH
TO PRODUCE WIDESPREAD FROST. CONSIDERED DROPPING FREEZE WARNING TOO
GIVEN CURRENT READINGS...BUT WITH ONLY THE TYPICAL COLD SPOTS IN
CENTRAL WISCONSIN BELOW FREEZING...WILL LET IT CONTINUE FOR NOW.
TODAY AND TONIGHT...FOCUS IS ON THE SHORTWAVE OVER NORTH DAKOTA.
GOOD MODEL AGREEMENT EXISTS OF THE SHORTWAVE TRACKING SOUTHEAST INTO
WESTERN IOWA BY THIS EVENING AND INTO SOUTHERN ILLINOIS LATE
TONIGHT. LOW PRESSURE AREA ACCOMPANYING THE SHORTWAVE TAKES PRETTY
MUCH THE SAME TRACK...WITH AN INVERTED TROUGH LINGERING BACK INTO
SOUTHWEST MINNESOTA AT THE SURFACE AFTER IT PASSES. ALTHOUGH THE
SHORTWAVE AND SURFACE FEATURES ARE TRACKING WEST OF HERE...WE STILL
SEE 30-40 METER 500MB HEIGHT FALLS TODAY...UPPER DIVERGENCE IN THE
LEFT EXIT REGION OF THAT 100 KT JET THIS AFTERNOON...AND THAT
FRONTOGENESIS/FRONTOLYSIS COUPLET IN THE LOW TO MID LEVELS MOVE
THROUGH WESTERN SECTIONS OF THE FORECAST AREA THIS AFTERNOON AND
EVENING. WITH A SURGE OF PRECIPITABLE WATER ACCOMPANYING THE
SYSTEM...UP TO 0.5 INCH OR SO...PRECIPITATION SEEMS TO BE A PRETTY
GOOD BET. HAVE RAISED CHANCES UP TO 100 FOR LOCATIONS MAINLY WEST OF
THE MISSISSIPPI RIVER FOR THIS AFTERNOON AND EVENING. FOR LOCATIONS
NORTH AND EAST OF I-94...THEY ARE ON THE WRONG / SUBSIDENT SIDE OF
THE FRONTOGENETICAL CIRCULATION. THEREFORE...DRY CONDITIONS ARE
MOSTLY EXPECTED THERE. TOTAL QPF AMOUNTS COULD BE UPWARDS OF 0.30
INCHES...A FAR CRY FROM THURSDAY. LOOK FOR PRECIPITATION TO DIMINISH
AFTER MIDNIGHT AS FORCING WEAKENS AND/OR SHIFTS SOUTHEAST OF HERE.
WITH A LOT OF CLOUDS TODAY AND EVENTUALLY RAIN COMING IN THIS
AFTERNOON FOR SOME AREAS...AS WELL AS 850MB TEMPS OF 0 TO -2C...
EXPECTING COOLER TEMPERATURES TODAY. STAYED ON THE COOL SIDE OF
GUIDANCE OUT WEST THEN A BLEND ELSEWHERE. MAY SEE A LITTLE DROP IN
TEMPS IN THE AFTERNOON WHERE IT RAINS DUE TO EVAPORATIVE COOLING. A
BLEND OF GUIDANCE SEEMS REASONABLE FOR LOWS TONIGHT BEING UNDER
PERSISTENT CLOUDS.
SUNDAY AND SUNDAY NIGHT...500MB HEIGHTS PROGGED TO RISE OVER THE
FORECAST AREA DURING MUCH OF THIS PERIOD IN THE WAKE OF
TODAY/TONIGHTS SHORTWAVE...THOUGH SOLIDLY REMAINING IN NORTHWEST
FLOW ALOFT. AS THE HEIGHTS RISE...THE INVERTED TROUGH OVER SOUTHWEST
MINNESOTA WEAKENS AND PUSHES EAST TOWARDS THE MISSISSIPPI RIVER BY
00Z. LOW LEVEL CONVERGENCE ON THIS TROUGH IN CONJUNCTION WITH
DAYTIME HEATING COULD BE ENOUGH TO PRODUCE A FEW SHOWERS...THOUGH
CONFIDENCE IS PRETTY LOW GIVEN THAT CLOUD COVER MAY PERSIST THROUGH
MUCH OF THE DAY. PLUS...AN EASTERLY FLOW IS PROGGED TO DEVELOP OVER
WISCONSIN AHEAD OF HIGH PRESSURE DROPPING DOWN INTO LAKE SUPERIOR.
THIS EASTERLY FLOW WILL DRIVE DRY AIR INTO THE AREA. MOST MODELS
ARE EITHER DRY OR CLOSE TO IT WITH QPF FIELDS. THEREFORE...HAVE
REDUCED PRECIPITATION CHANCES BY 10 PERCENT AND SHIFTED THE MAX AREA
WESTWARD CLOSER TO THE INVERTED TROUGH. ANY PRECIP WILL END BY 00Z
MONDAY AS THE SURFACE RIDGE BUILDS INTO THE AREA. TEMPERATURES ARE A
LITTLE TRICKY FOR SUNDAY NIGHT AS MODELS NOW SUGGEST SOME CLOUDS
UP AROUND THE DULUTH AREA DROPPING SOUTH WITH THE SURFACE RIDGE. AS
SUCH...FOR NOW LEANED A LITTLE CLOSER TO A MODEL CONSENSUS...SAME
TOO FOR HIGHS ON SUNDAY. CERTAINLY IF WE CLEAR OUT MORE THAN
EXPECTED...FROST/FREEZE CONDITIONS MAY BECOME A WORRY FOR SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT...THE FORECAST AREA IS EXPECTED TO BE STUCK
BETWEEN STRONG RIDGING IN THE WESTERN U.S. AND DEEP TROUGHING OVER
THE EASTERN U.S.. THE POSITION FAVORS HIGH PRESSURE AT THE
SURFACE...WHICH HOLDS TRUE FOR THE DAY MONDAY. THERE ARE SUGGESTIONS
OF A SLIGHT EASTWARD PUSH OF THE UPPER RIDGE MONDAY NIGHT...WHICH IN
TURN CAUSES A WARM ADVECTION SURGE INTO THE FORECAST AREA. 850MB
TEMPS CLIMB FROM 2-4C AT 00Z TUESDAY TO 6-10C AT 12Z TUESDAY. THE
21.00Z GFS/NAM DEVELOP QPF WITH THIS SURGE OF WARM ADVECTION OVER
NORTHERN AND EASTERN WISCONSIN...POSSIBLY CLIPPING TAYLOR AND ADAMS
COUNTIES. FOR NOW HAVE DECIDED TO KEEP IT DRY IN AGREEMENT WITH THE
ECMWF AND PREVIOUS FORECASTS...THINKING TOO THAT THERE IS NOT MUCH
MOISTURE TO WORK WITH AFTER BEING UNDER THE SURFACE HIGH PRESSURE
RIDGE. SOMETHING TO WATCH...THOUGH. WITH MAINLY SUNNY SKIES ON
MONDAY AND THE WARMING 850MB TEMPS...DEEP MIXING SHOULD OCCUR WITH
HIGHS TOPPING OUT IN THE UPPER 50S/LOW 60S. INCREASING SOUTHWEST
FLOW AHEAD OF A SURFACE TROUGH DROPPING DOWN INTO NORTHERN WISCONSIN
MONDAY NIGHT AND THE WARMER 850MB TEMPS COMING IN SHOULD HELP TO
PRODUCE A WARMER NIGHT.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
342 AM CDT SAT APR 21 2012
BETTER AGREEMENT EXISTS WITH THE 21.00Z ECMWF/GFS/CANADIAN AND GFS
ENSEMBLES TODAY THAN SEEN YESTERDAY. THE WESTERN RIDGE AND EASTERN
TROUGH PATTERN SEEN RECENTLY LOOKS TO CONTINUE THROUGH MUCH OF THE
LONG TERM FORECAST...THOUGH TOWARDS FRIDAY SOME FAIRLY DEEP
TROUGHING DEVELOPS ALONG THE WEST COAST OF THE U.S. TO HELP PUSH
THAT WESTERN RIDGE EASTWARD. WE GET A BRIEF TASTE OF THE WARM AIR
OUT OF THE UPPER RIDGE TUESDAY AND TUESDAY NIGHT...AHEAD OF A LOW
PRESSURE AREA DEEPENING OVER THE DAKOTAS AND SLIDING DOWN INTO IOWA.
WARM ADVECTION AHEAD OF THIS LOW SHOULD PRODUCE SOME SHOWERS AND
POSSIBLY THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY. LOCATIONS WEST
OF THE MISSISSIPPI RIVER SEEM MOST FAVORABLE RIGHT NOW FOR
PRECIPITATION. HIGH PRESSURE THEN DROPS IN FROM CANADA FOR WEDNESDAY
NIGHT THROUGH FRIDAY NIGHT...WITH MAYBE A BRIEF DRY COLD FRONT
MOVING THROUGH BETWEEN THEN ON THURSDAY NIGHT. THEREFORE...WHEN IT
COMES TO TEMPERATURES...WARMEST READINGS ARE EXPECTED ON TUESDAY AND
WEDNESDAY. MAY HAVE TO DEAL WITH FROST/FREEZE CONDITIONS THURSDAY
NIGHT OR FRIDAY NIGHT OVER CENTRAL WISCONSIN. SOMETHING TO WATCH.
&&
.AVIATION...
1100 PM CDT FRI APR 20 2012
HIGH CLOUDS WILL BE ON THE INCREASE OVERNIGHT...AHEAD OF AN UPPER
LEVEL SHORTWAVE TROUGH DROPPING OVER THE NORTHERN PLAINS. THE CLOUDS
WILL CONTINUE TO INCREASE AND LOWER ON SAT...ALTHOUGH EXPECTATIONS
ARE THAT VFR CONDITIONS WILL PERSIST THROUGH MUCH OF THE AFTERNOON.
THAT SAID...THE TRACK OF THE SFC LOW IS TO THE WEST...AND CLOSER TO
KRST. THINK MVFR CIGS WILL MOVE IN FOR SAT NIGHT...AS BUFKIT
SOUNDINGS AND RH FIELDS ARE SATURATED TO THE SFC. ALONG WITH THIS
LOWERING OF THE CLOUD DECK WILL COME AREAS OF -SHRA. LATEST TRACK
VIA THE GFS40/ECMWF SUGGEST THE BEST PCPN CHANCES WILL BE ACROSS
MN/IA...MOSTLY FROM THE MISSISSIPPI RIVER WESTWARD. THE 00Z NAM12 IS
SIMILAR. WILL CONTINUE PCPN MENTION AT KRST/KLSE...WITH SOME
REDUCTION IN VSBY AFTER 00Z.
ANOTHER CONCERN FOR TONIGHT IS THE POSSIBILITY OF FOG. DECENT SETUP
WITH SOAKING RAINS THE PREVIOUS DAY...AND CLEAR SKIES/LIGHT WINDS
OVERNIGHT. HOWEVER...BUFKIT SOUNDINGS POINT TO AN INCREASE IN WINDS
JUST OFF THE SFC TOWARD 12Z AS AN AREA OF HIGH PRESSURE SLIPS TO THE
EAST. IN ADDITION...THERE IS THE INCREASE IN HIGH CLOUDS FROM THE
WEST. AT THIS TIME...DON/T FEEL THE POTENTIAL FOR BR IS HIGH ENOUGH
TO INCLUDE IN THE TAFS. KLSE WOULD HAVE THE HIGHER THREAT...AND OBS
AND CONDITIONS WILL HAVE TO BE MONITORED THROUGH THE NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CDT SAT APR 21 2012
WI...FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-034-
042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1159 AM EDT SAT APR 21 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE WEST TODAY...THEN CROSS THE
REGION TONIGHT. ANOTHER LOW WILL LIFT NORTH ALONG THE COAST
SUNDAY...THEN TRACK SOUTHWEST OF THE REGION MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...LATEST HRRR CONTINUES TO DELAY THE ONSET OF THE STEADIER
RAINFALL INTO THE NW CWA UNTIL LATE AFTERNOON. CURRENT RADAR
CONFIRMS THIS WITH LITTLE IN THE WAY OF ANY PRECIP AT TIME.
THEREFORE...HAVE DECREASED THE CHANCE OF PRECIPITATION THROUGH EARLY
AFTERNOON. TEMPERATURES ACROSS THE NORTH HAVE BEEN TRICKY THUS
FAR AS THEY HAVE RISEN QUITE RAPIDLY WHERE THERE ARE BREAKS
HOWEVER AS CLOUDS FILL IN AHEAD THE FRONT TEMPERATURES WILL LEVEL
OFF. SOUTH WIND OFF THE GULF OF MAINE WILL HOLD TEMPERATURES DOWN
ALONG THE COAST THUS LOWERED HIGHS HERE.
PREVIOUS DISCUSSION... A FRONTAL BOUNDARY LOCATED
ACROSS NORTHERN MAINE THIS MORNING WILL BEGIN TO SINK SOUTH THIS
AFTERNOON WHILE LOW PRESSURE APPROACHES FROM THE WEST. THE BEST
CHANCES FOR RAIN TODAY WILL OCCUR ACROSS NORTHERN/NORTHWESTERN
PORTIONS OF THE FORECAST AREA. AFTER MORNING SHOWERS...RAIN
CHANCES WILL INCREASE DOWNEAST THIS AFTERNOON WITH THE APPROACH OF
THE LOW AND FRONT. THE LOW WILL CROSS THE FORECAST AREA
TONIGHT...DRAWING THE COLD FRONT SOUTH OF THE REGION. THE LOW AND
FRONT WILL BRING RAIN TO THE ENTIRE FORECAST AREA TONIGHT. ACROSS
NORTHERN/NORTHWESTERN PORTIONS OF THE FORECAST AREA...ENOUGH COLD
AIR COULD BE DRAWN SOUTHWARD TO ALLOW A RAIN/SNOW MIX TO DEVELOP
LATER TONIGHT THOUGH LITTLE OR NO SNOW ACCUMULATION IS EXPECTED.
HIGH TEMPERATURES ACROSS NORTHERN PORTIONS OF THE FORECAST AREA
TODAY WILL BE DEPENDENT ON THE LOCATION OF THE FRONTAL BOUNDARY
WITH READINGS GENERALLY RANGING THROUGH THE 50S. ACROSS
CENTRAL/INTERIOR DOWNEAST PORTIONS OF THE FORECAST AREA HIGH
TEMPERATURES ARE EXPECTED TO RANGE FROM AROUND 60 TO THE LOWER
60S. COOLER TEMPERATURES WILL OCCUR ALONG THE DOWNEAST COAST WHERE
ONSHORE WINDS WILL HELP KEEP TEMPERATURES IN THE MID TO UPPER 50S.
LOW TEMPERATURES TONIGHT ARE EXPECTED TO RANGE FROM THE MID TO
UPPER 30S NORTH...TO THE LOWER TO MID 40S DOWNEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
EXPECT INITIAL AREA OF LOW PRESSURE MOVING NORTHEAST INTO
MARITIMES AND AWAY FROM THE REGION AT THE BEGINNING OF THIS
PERIOD. TRAILING COLD FRONT WILL BECOME STATIONARY OVER THE GULF
OF MAINE LATE SUNDAY AS WEAK HIGH PRESSURE BRIEFLY BUILDS IN FROM
WEST BEHIND THE FRONT. A SECOND AREA OF LOW PRESSURE WILL MOVE
NORTHWARD ALONG THE FRONT SUNDAY EVENING SPREADING MORE
PRECIPITATION ACROSS THE FORECAST AREA. THIS SYSTEM WILL MOVE
NORTHWARD AND PASS TO THE WEST OF NEW ENGLAND LATE MONDAY. MOST
OPERATIONAL RUNS AND INDIVIDUAL GFS ENSEMBLE MEMBERS NOW SUPPORT
THIS WESTERLY TRACK. WITH STRONG HIGH PRESSURE POSITIONED TO THE
NORTH EXPECT WINDY CONDITIONS SUNDAY NIGHT INTO MONDAY. ALSO WITH
LOW LEVEL COLD AIR DRAINAGE IN NORTHEAST FLOW COULD BE SOME MIXED
PRECIPITATION FAR NORTH SUNDAY NIGHT BUT EXPECT MOST PRECIPITATION
IN LIQUID FORM. HAVE BLENDED GFS40...NAM12 AND SREF FOR POPS AND
QPF. FOR WIND WILL BLEND THE NAM12 AND GMOS. HAVE USED 135 PERCENT
OF SUSTAINED WIND FOR GUSTS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
INTENSE LOW PRESSURE GRADUALLY WEAKENS MONDAY NIGHT INTO TUESDAY
AND MOVES NORTH INTO WESTERN QUEBEC PROVINCE. EXPECT COLDER AIR TO
FILTER IN BEHIND UPPER 500 MILLIBAR TROUGH DURING THE DAY
WEDNESDAY. ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OFF
THE MID ATLANTIC STATES WEDNESDAY NIGHT THEN MOVE NORTHWARD INTO
GULF OF MAINE LATE THURSDAY. WITH COLDER AIR IN PLACE COULD BE
SOME SNOW/MIXED PRECIPITATION WITH THIS SYSTEM NORTH BUT RIGHT NOW
EXPECT MOSTLY LIQUID. WILL INITIALIZE GRIDS WITH GMOS. HAVE
ADJUSTED POPS...MINIMUM TEMPERATURES AND WIND GRIDS.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: OCCASIONAL MVFR CONDITIONS ARE EXPECTED ACROSS THE REGION
TODAY. MVFR/IFR CONDITIONS ARE EXPECTED ACROSS THE REGION TONIGHT.
SHORT TERM: IFR/MVFR CONDITIONS ARE POSSIBLE SUNDAY THROUGH
WEDNESDAY.
&&
.MARINE...
NEAR TERM: A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS REMAINS IN
EFFECT FOR MUCH OF THE WATERS...WITH THE EXCEPTION OF THE
INTRACOASTAL WATERS...TODAY THROUGH TONIGHT. VISIBILITIES WILL BE
REDUCED IN ANY SHOWERS OR RAIN TODAY...WITH RAIN AND PATCHY FOG
TONIGHT.
SHORT TERM: HAVE USED A BLEND OF NAM12 AND GFS40 SUNDAY AND MONDAY
THEN TRANSITION TO GMOS WINDS. FOR WAVES HAVE USED THE WNA/4. LONG
SOUTHERLY FETCH IN PLACE GULF OF MAINE SOUTHWARD SUNDAY AND MONDAY
WITH INTENSE LOW PRESSURE WEST OF NEW ENGLAND AND STRONG HIGH TO
EAST. SO EXPECT EXTENDED PERIOD OF LONG PERIOD WAVE TO PERSIST
THROUGH THIS FORECAST PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT SUNDAY
FOR ANZ050-051.
&&
$$
NEAR TERM...DUDA/NORCROSS
SHORT TERM...MIGNONE
LONG TERM...MIGNONE
AVIATION...DUDA/NORCROSS
MARINE...DUDA/NORCROSS/MIGNONE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1021 AM EDT SAT APR 21 2012
.SYNOPSIS...
LOW PRESSURE WILL APPROACH FROM THE WEST TODAY...THEN CROSS THE
REGION TONIGHT. ANOTHER LOW WILL LIFT NORTH ALONG THE COAST
SUNDAY...THEN TRACK SOUTHWEST OF THE REGION MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...HAVE UPDATED THE FORECAST TO BACK UP THE TIMING OF THE
STEADIER RAIN UNTIL LATER THIS AFTERNOON. LATEST HRRR INDICATING
THAT THE STEADIER RAIN WONT MAKE IT INTO THE FA UNTIL LATER THIS
AFTERNOON AND ONLY EXPECTING SCT SHOWERS UNTIL THEN. HAVE ALSO
INCLUDED PATCHY FOG FOR THE COAST.
PREVIOUS DISCUSSION...
A FRONTAL BOUNDARY LOCATED ACROSS NORTHERN MAINE THIS MORNING
WILL BEGIN TO SINK SOUTH THIS AFTERNOON WHILE LOW PRESSURE
APPROACHES FROM THE WEST. THE BEST CHANCES FOR RAIN TODAY WILL
OCCUR ACROSS NORTHERN/NORTHWESTERN PORTIONS OF THE FORECAST AREA.
AFTER MORNING SHOWERS...RAIN CHANCES WILL INCREASE DOWNEAST THIS
AFTERNOON WITH THE APPROACH OF THE LOW AND FRONT. THE LOW WILL
CROSS THE FORECAST AREA TONIGHT...DRAWING THE COLD FRONT SOUTH OF
THE REGION. THE LOW AND FRONT WILL BRING RAIN TO THE ENTIRE
FORECAST AREA TONIGHT. ACROSS NORTHERN/NORTHWESTERN PORTIONS OF
THE FORECAST AREA...ENOUGH COLD AIR COULD BE DRAWN SOUTHWARD TO
ALLOW A RAIN/SNOW MIX TO DEVELOP LATER TONIGHT THOUGH LITTLE OR NO
SNOW ACCUMULATION IS EXPECTED. HIGH TEMPERATURES ACROSS NORTHERN
PORTIONS OF THE FORECAST AREA TODAY WILL BE DEPENDENT ON THE
LOCATION OF THE FRONTAL BOUNDARY WITH READINGS GENERALLY RANGING
THROUGH THE 50S. ACROSS CENTRAL/INTERIOR DOWNEAST PORTIONS OF THE
FORECAST AREA HIGH TEMPERATURES ARE EXPECTED TO RANGE FROM AROUND
60 TO THE LOWER 60S. COOLER TEMPERATURES WILL OCCUR ALONG THE
DOWNEAST COAST WHERE ONSHORE WINDS WILL HELP KEEP TEMPERATURES IN
THE MID TO UPPER 50S. LOW TEMPERATURES TONIGHT ARE EXPECTED TO
RANGE FROM THE MID TO UPPER 30S NORTH...TO THE LOWER TO MID 40S
DOWNEAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
EXPECT INITIAL AREA OF LOW PRESSURE MOVING NORTHEAST INTO
MARITIMES AND AWAY FROM THE REGION AT THE BEGINNING OF THIS
PERIOD. TRAILING COLD FRONT WILL BECOME STATIONARY OVER THE GULF
OF MAINE LATE SUNDAY AS WEAK HIGH PRESSURE BRIEFLY BUILDS IN FROM
WEST BEHIND THE FRONT. A SECOND AREA OF LOW PRESSURE WILL MOVE
NORTHWARD ALONG THE FRONT SUNDAY EVENING SPREADING MORE
PRECIPITATION ACROSS THE FORECAST AREA. THIS SYSTEM WILL MOVE
NORTHWARD AND PASS TO THE WEST OF NEW ENGLAND LATE MONDAY. MOST
OPERATIONAL RUNS AND INDIVIDUAL GFS ENSEMBLE MEMBERS NOW SUPPORT
THIS WESTERLY TRACK. WITH STRONG HIGH PRESSURE POSITIONED TO THE
NORTH EXPECT WINDY CONDITIONS SUNDAY NIGHT INTO MONDAY. ALSO WITH
LOW LEVEL COLD AIR DRAINAGE IN NORTHEAST FLOW COULD BE SOME MIXED
PRECIPITATION FAR NORTH SUNDAY NIGHT BUT EXPECT MOST PRECIPITATION
IN LIQUID FORM. HAVE BLENDED GFS40...NAM12 AND SREF FOR POPS AND
QPF. FOR WIND WILL BLEND THE NAM12 AND GMOS. HAVE USED 135 PERCENT
OF SUSTAINED WIND FOR GUSTS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
INTENSE LOW PRESSURE GRADUALLY WEAKENS MONDAY NIGHT INTO TUESDAY
AND MOVES NORTH INTO WESTERN QUEBEC PROVINCE. EXPECT COLDER AIR TO
FILTER IN BEHIND UPPER 500 MILLIBAR TROUGH DURING THE DAY
WEDNESDAY. ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OFF
THE MID ATLANTIC STATES WEDNESDAY NIGHT THEN MOVE NORTHWARD INTO
GULF OF MAINE LATE THURSDAY. WITH COLDER AIR IN PLACE COULD BE
SOME SNOW/MIXED PRECIPITATION WITH THIS SYSTEM NORTH BUT RIGHT NOW
EXPECT MOSTLY LIQUID. WILL INITIALIZE GRIDS WITH GMOS. HAVE
ADJUSTED POPS...MINIMUM TEMPERATURES AND WIND GRIDS.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: OCCASIONAL MVFR CONDITIONS ARE EXPECTED ACROSS THE REGION
TODAY. MVFR/IFR CONDITIONS ARE EXPECTED ACROSS THE REGION TONIGHT.
SHORT TERM: IFR/MVFR CONDITIONS ARE POSSIBLE SUNDAY THROUGH
WEDNESDAY.
&&
.MARINE...
NEAR TERM: A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS REMAINS IN
EFFECT FOR MUCH OF THE WATERS...WITH THE EXCEPTION OF THE
INTRACOASTAL WATERS...TODAY THROUGH TONIGHT. VISIBILITIES WILL BE
REDUCED IN ANY SHOWERS OR RAIN TODAY...WITH RAIN AND PATCHY FOG
TONIGHT.
SHORT TERM: HAVE USED A BLEND OF NAM12 AND GFS40 SUNDAY AND MONDAY
THEN TRANSITION TO GMOS WINDS. FOR WAVES HAVE USED THE WNA/4. LONG
SOUTHERLY FETCH IN PLACE GULF OF MAINE SOUTHWARD SUNDAY AND MONDAY
WITH INTENSE LOW PRESSURE WEST OF NEW ENGLAND AND STRONG HIGH TO
EAST. SO EXPECT EXTENDED PERIOD OF LONG PERIOD WAVE TO PERSIST
THROUGH THIS FORECAST PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT SUNDAY
FOR ANZ050-051.
&&
$$
NEAR TERM...DUDA/NORCROSS
SHORT TERM...MIGNONE
LONG TERM...MIGNONE
AVIATION...DUDA/NORCROSS
MARINE...DUDA/NORCROSS/MIGNONE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1000 AM EDT SAT APR 21 2012
.SYNOPSIS...
A COLD FRONT WILL PUSH THROUGH THE AREA TODAY BRINGING COOLER AIR
AND RAIN TO THE AREA. THE FRONT WILL STALL ALONG THE EAST COAST
TONIGHT. A INTENSE LOW WILL MOVE UP THE EAST COAST SUNDAY, AND
INTO UPSTATE NEW YORK MONDAY. THIS LOW WILL SPREAD RAIN BACK INTO
THE AREA SUNDAY NIGHT INTO MONDAY NIGHT. COLD AIR OVER WESTERN AND
CENTRAL NEW YORK AND NORTHERN PENNSYLVANIA, MAY SWITCH THE RAIN
TO SNOW AND BRING THOSE AREAS A FEW INCHES OF ACCUMULATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...A COLD FRONT CONTINUES TO MARCH ACROSS THE CWA ATTM
WITH THE MAIN SHIELD OF RAIN BEHIND THE FRONT...AND ONLY ISOLATED
SHOWERS JUST AHEAD OF IT. TEMP CHANGES ARE SHARP WITH KITH AND
KSYR NOW INTO THE UPPER 40S BEHIND THE FRONT...WITH LOWER 60S AT
TOWANDA...BINGHAMTON...AND HAMILTON JUST AHEAD OF THE FRONT.
EXPECT TEMPS TO COOL BACK INTO THE 40S AND 50S WITH THE FROPA THIS
AFTERNOON EXCEPT FOR THE FAR SE WHICH WON`T SEE THE FRONT UNTIL
LATER IN THE DAY.
TRIMMED BACK RAIN CHANCES A BIT ON THE FRONT EDGE. IT APPEARS OUR
MOST STEADY RAIN WILL HANG ACROSS THE WESTERN PART OF THE CWA
THROUGH EARLY AFTERNOON AND NOT MAKE HUGE PROGRESS EAST UNTIL
LATER TODAY. WE STILL REMAIN IN SEE TEXT ACROSS THE EXTREME FAR
SOUTHEAST FOR SEVERE WEATHER. A MARINE LAYER WHICH IS IN THE
PROCESS OF BURNING OFF WILL PUT A DAMPER ON OUR CHANCES. THIS IS
SHOWN NICELY BY THE RUC SHOWING CAPES ONLY IN THE 100 - 300 J/KG
RANGE THIS AFTERNOON AT MSV. THE NAM IS A BIT HIGHER BUT BOTH
MODELS SHOW A BIT OF A CAP BETWEEN 5000 AND 1000 FEET...WHICH WILL
FURTHER LIMIT ACTIVITY. IF WE SEE ANY STORMS FORM...THE BEST
CHANCE WILL BE ACROSS OUR EXTREME FAR SOUTHEAST AND THE
POTENTIAL WILL MAINLY BE FOR WIND WITH AN INVERTED V SOUNDING.
IT APPEARS OUR CHANCES FOR RAIN GO DOWN SHARPLY AFTER 06Z TONIGHT
SO I MADE THE ENTIRE AREA DRY LATE TONIGHT INTO EARLY SUNDAY TO
SHOW A BREAK IN BETWEEN OUR TWO SYSTEMS. MORE ON THE NEXT SYSTEM
LATER THIS AFTERNOON.
4 AM UPDATE... BIG CHANGES TO OUR RECENT MILD DRY PATTERN.
FIRST WITH A COLD FRONT AND RAIN SHOWERS TODAY THEN A STACKED LOW
WITH SNOW AND RAIN FOR SUNDAY TO TUESDAY.
ATTM A NE TO SW COLD ANAFRONT IS ACROSS NRN AND WRN NY. THIS WILL
MOVE SLOWLY EAST TODAY AND TO THE EAST COAST TONIGHT. SHOWERS
BEHIND THE FRONT WILL MOVE INTO CENTRAL NY THIS MORNING THEN INTO
NE PA AND THE CATSKILLS THIS AFTN. HIGHS WILL BE JUST AHEAD OF THE
SFC FRONT. THE HIGHEST TEMPS WILL BE ACROSS THE FAR SE WITH U60S
AND L70S. IN THIS AREA SOME ATLANTIC MOISTURE CAUSING LOW CLOUDS
BUT THIS WILL EXIT SO THAT SOME SUN IS POSSIBLE MIDDAY. ALSO MODEST
LOW LEVEL INSTABILITY COULD CAUSE A THUNDERSTORM THIS AFTN.
IN CENT NY TEMPERATURES WILL NOT BE WARM ENOUGH FOR THUNDERSTORMS.
THIS AFTN TEMPERATURES FALL THROUGH THE 40S AND INTO THE 30S
TONIGHT. IN THE SE TEMPS FALL INTO THE 40S.
SHOWERS WILL END IN NY LATE TODAY AND IN NE PA AND SULLIVAN COUNTY
NY THIS EVENING. RAINFALL BEHIND THE FRONT WILL BE A QUARTER TO
HALF AN INCH. POSSIBLY SOME HIGHER AMOUNTS IN THUNDERSTORMS. WITH
IT BEING SO DRY THIS MONTH LITTLE WILL RUN OFF.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
4 AM UPDATE...
A STRONG STORM WILL MOVE OUT OF THE GULF OF MEXICO AND UP THE EAST
COAST SUNDAY. THE SFC LOW INTENSIFIES THE WHOLE WAY. A DEEP UPPER
LEVEL TROF CLOSES OFF OVER THE OHIO VALLEY CAUSING THE SFC LOW TO
TURN NORTH THEN NE INTO UPSTATE NY. MONDAY NIGHT THE UPPER AND
SURFACE LOWS BECOME STACKED AND MOVE SLOWLY NORTH INTO SE CANADA.
MODELS IN BETTER AGREEMENT NOW WITH A SFC TRACK UP THE HUDSON
VALLEY. CENTRAL NY AND NE PA COULD GET 1 TO 2 INCHES LIQUID WITH
THIS STORM. RAIN MOVES IN AHEAD OF THE LOW LATE SUNDAY AND SUNDAY
NIGHT TO COVER THE WHOLE AREA. TEMPERATURES ARE WARM ENOUGH TO
START AS RAIN BUT ACROSS THE HIGHER TERRAIN ESPECIALLY IN NY WEST
OF THE CATSKILLS IT WILL MIX WITH SNOW. THE FURTHER WEST YOU GO
THE COLDER IT WILL BE SO THE COLDEST AIR WILL BE IN STEUBEN
COUNTY. PRECIP SHOULD CHANGE TO JUST SNOW LATE SUNDAY NIGHT.
MIDDAY MONDAY DAYTIME HEATING WILL CAUSE MOST OF THE PRECIP TO
CHANGE TO RAIN BEFORE CHANGING BACK TO A MIX OR SNOW MONDAY NIGHT.
LOW LEVELS CLOSE TO FREEZING SO ELEVATION WILL BE A FACTOR TOO.
SURFACE TEMPERATURES MOSTLY IN THE 30S SUNDAY NIGHT TO MONDAY
NIGHT. WITH THE WARMEST AIR OVER THE CATSKILLS AND POCONOS SNOW
AMOUNTS THERE ARE EXPECTED TO BE LESS THAN AN INCH. HIGH TEMPS
SUNDAY IN THE 50S AND AROUND 50 MONDAY. THE HIGHEST AMOUNTS OF
SEVERAL INCHES WILL BE ACROSS THE HIGHER TERRAIN IN CORTLAND
COUNTY...THE CENTRAL SOUTHERN TIER AND FINGER LAKES OF NY...AND
BRADFORD COUNTY PA. IN WESTERN STEUBEN COUNTY 6 TO 12 IS POSSIBLE.
EVEN WITH 1 TO 2 INCHES OF LIQUID RIVERS ARE NOT EXPECTED TO
FLOOD. VERY LOW RIVER LEVELS FOR APRIL. WILL NEED TO WATCH THE
DELAWARE BASINS SUNDAY NIGHT TO MONDAY WITH UP TO ONE INCH EACH 6
HOURS WITH TOTALS AROUND 3 INCHES. THIS AMOUNT WILL CAUSE RAPID
RISES ON THE STREAMS AND CREEKS. ONCE THE SFC LOW PASSES MONDAY
RAIN WILL END IN MOST OF NE PA AND THE CATSKILLS FOR MONDAY NIGHT.
WRAPAROUND MIXED PRECIP WILL CONTINUE IN CENTRAL AND WRN NY MONDAY
TO TUESDAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
4 AM SAT UPDATE... NO CHANGES TO THE EXTENDED GRIDS ATTM.
00Z SAT NWP SUITE REMAINS IN FAIRLY GOOD AGREEMENT ON THE
LARGE-SCALE...WITH AN AMPLIFIED PATN IN PLACE TO START THE
PD...FEATURING A DEEP SERN CANADIAN/ERN CONUS TROUGH AXIS...HELD IN
PLACE BY HIGHER LAT BLOCKING EXTENDING INTO GREENLAND...AND ALSO A
WRN CONUS RIDGE. THERE IS DECENT CONSENSUS THAT MID TO UPR-LVL
HEIGHTS WILL GRADUALLY RISE OVER THE ERN U.S. BY LATER NEXT
WEEK...BUT THAT THE PRIMARY TROUGH AXIS WILL REMAIN IN PLACE. AS A
RESULT...WE CAN EXPECT A CHILLY PD OVERALL...WITH TEMPS AVERAGING
BELOW CLIMATOLOGICAL NORMS FOR LATE APRIL.
DAILY WX-WISE...MOIST CYCLONIC FLOW UNDERNEATH THE ABV MENTIONED
TROUGH FEATURE WILL KEEP OUR WX UNSETTLED THROUGH AT LEAST WED...AND
POSSIBLY INTO THU...WITH -SHRA IN THE FCST. BLYR TEMPS CONTINUE TO
LOOK COLD ENOUGH FOR -SHSN TO MIX DURG THE NIGHTTIME/EARLY MRNG
HRS...SPCLY OVER THE HIGHER TERRAIN. BY FRI...THERE IS SOME
INDICATION THAT DRIER AIR MAY PUSH DOWN INTO NY/PA OUT OF ERN
CANADA...AS A SFC RIDGE BUILDS SWD. TEMPS...THOUGH...SHOULD REMAIN
ON THE COOL SIDE.
PREVIOUS DISCUSSION...
MAJOR STORM WILL BE WINDING DOWN DURING THE BEGINNING OF THE
EXTENDED PERIOD. THE PERIOD BEGINS WITH VERTICALLY STACKED LOW
PRESSURE NEAR LAKE ONTARIO MONDAY NIGHT. MOISTURE WRAPPING AROUND
THIS SYSTEM WILL SPREAD SOME LIGHT RAIN AND SNOW SHOWERS ACROSS
THE AREA MONDAY NIGHT INTO TUESDAY EVENING ALONG WITH GUSTY
WESTERLY WINDS. DRYER... COOL WEATHER WILL FOLLOW IN THE WAKE OF
THIS SYSTEM TUESDAY NIGHT. OVERALL PATTERN LOOKS CONTINUED COOL
WEDNESDAY INTO SATURDAY. A CLIPPER SYSTEM COULD MOVE ACROSS THE
AREA AT SOME TIME DURING THIS TIME WITH A PERIOD OF SHOWERS.
TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS GENERALLY IN THE
LOWER TO MID 50S AND LOWS MOSTLY IN THE 30S.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
12Z UPDATE... VFR SHOULD HANG ON A LTL LONGER...BUT RESTRICTIONS
ARE COMING INTO THE AREA THIS MRNG...AND WE SHOULD SEE DETERIORATING
CONDS FOR THE MAJORITY OF OUR TAF SITES BY 12-15Z. OUR BEST GUESS AT
THIS PT IS LOW MVFR TO SOME IFR...SPCLY THIS AFTN...WHEN STEADIER
-RA MOVES IN. THE MOST PROBABLE SITE TO SEE CONDS FALL BELOW ALT
MINS IS KITH.
THE EXCEPTION TO ALL OF THIS IS KAVP...WHERE VFR SHOULD PERSIST FOR A
GOOD PTN OF THE DAY...AS IT WILL TAKE THE APPROACHING FRNTL BNDRY
AND AXIS OF MOIST MUCH LONGER TO REACH HERE. HOWEVER...EVEN
HERE...MVFR SHOULD ULTIMATELY DEVELOP BY LATE AFTN...CONTINUING
INTO THE EVE. THERE COULD BE SCTD SHRA DEVELOPMENT ACRS NE PA THIS
AFTN...JUST PRIOR TO FROPA...WITH EVEN A LOW PROBABILITY FOR TSRA.
AT THIS JUNCTURE...THE TSRA THREAT DOESN`T YET JUSTIFY INCLUSION
IN THE TERMINAL FCST.
S TO SW WINDS EARLY THIS MRNG...WILL SWITCH INTO THE NW AND N FROM
ABT MID-MRNG ONWARD AT KITH/KBGM/KRME. AT KAVP...THOUGH...SW WINDS WILL PERSIST
TIL THIS AFTN...BEFORE THE WIND SHIFT TAKES PLACE.
TONIGHT...-RA WILL EXIT THE RGN FROM NW TO SE...IN THE 00-04Z TIME
FRAME. EVEN AFTER THE RAIN ENDS...THOUGH...MVFR CIGS ARE VERY
LIKELY TO LINGER.
.OUTLOOK...
SUN...MAINLY VFR...AT LEAST FOR THE AM HRS.
SUN NGT-MON...RESTRICTIONS WILL BECOME MORE LIKELY AGAIN...AS
STEADIER PCPN PROBABLY RE-DEVELOPS (COULD BE -RA OR -SN).
TUE INTO WED...RESTRICTIONS STILL PSBL (LINGERING CLDS/LWR CIGS...AND
PERHAPS -SHRA/-SHSN).
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC
NEAR TERM...HEDEN/TAC
SHORT TERM...TAC
LONG TERM...MLJ/MSE
AVIATION...MLJ/SLI
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 AM CDT SAT APR 21 2012
.DISCUSSION...FORECAST CHALLENGE CONCERNS PCPN
COVERAGE/LOCATION...WIND AND TEMPERATURES.
WELL DEFINED COMPACT MID LEVEL CIRCULATION DROPPING SE THROUGH FA AT
THIS TIME FROM WATER VAPOR IMAGERY. ASSOCIATED SURFACE LOW BETWEEN
DVL AND GFK TO PROPAGATE SE REACHING WEST CENTRAL/SW MN BY EVENING.
MAIN BAND OF SHRA EXTEND FROM WEST CENTRAL MN ARCING NW AROUND
SURFACE LOW ACROSS FAR NORTHERN FA. WILL ADJUST POPS ACCORDINGLY
LOWERING CHANCES ACROSS SE NE FOR AT LEAST THE MORNING. THIS
AFTERNOON AS THE LOW CONTINUES TO SLIDE SE RUC INDICATING AIRMASS
BECOMING SLIGHTLY UNSTABLE ACROSS FAR SOUTHERN FA ALONG SURFACE
BOUNDARY. FAVORED CAPE LOOKS TO BE JUST SOUTH OF FA AND NOT SURE HOW
THICK APPROACHING SC DECK WILL BE AT THIS POINT SO WILL LEAVE OUT T
MENTION HOWEVER NOT OUT OF THE QUESTION. GOOD DARKENING FROM WATER
VAPOR IMAGERY ACROSS SW FA IN SW FLANK OF PASSING WAVE. BEING IN
FAVORED WIND ZONE RELATIVE TO WAVE THIS AREA COULD SEE SOME STRONGER
NW WINDS BEHIND SURFACE BOUNDARY. MODEL SOUNDINGS INDICATING FAIRLY
DEEP MIXED LAYER WITH AROUND 30KTS TO MIX DOWN. WINDS SHOULD REMAIN
BLO ADVISORY CRITERIA BUT WILL STILL BE WINDY. FAR SE FA SEEING SOME
SOLAR THIS AM HOWEVER SC CLOUD DECK TO OVERSPREAD TO A DEGREE. THIS
AREA WILL SEE WARMEST TEMPERATURES WITH N/NE FA COOLEST BEING UNDER
CLOUDS LONGEST.
&&
.AVIATION...
MVFR/IFR SC DECK SPREADING SE ON BACK SIDE OF SURFACE LOW. AS LOW
CONTINUES TO PROPAGATE SE TODAY EXPECT THESE LOWER CIGS TO SPREAD
ACROSS MOST OF FA HOWEVER HOPEFULLY WILL INCREASE TO MAINLY MVFR
LEVELS THIS AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER/ROGERS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1101 AM CDT SAT APR 21 2012
.UPDATE...
LAKE CLOUDS FORMED ALONG A CONVERGENCE ZONE NEAR THE LAKESHORE
THIS MORNING. EXPECT THESE CLOUDS TO MIX OUT NEAR THE SHORELINE
AND ADVECT INLAND UP TO THE KETTLE MORRAINE LATE THIS
MORNING...THEN MIX OUT AFTER 18Z. CU RULE GENERALLY SUPPORTIVE OF
SCATTERED TO BROKEN CLOUDS DURING THE AFTERNOON FOR INLAND
LOCATIONS...EXCEPT FOR THE NAM. RUC SNDGS ALSO SHOW POTENTIAL FOR
SCATTERED CU ACROSS MUCH OF SOUTH CENTRAL WI.
MAX TEMPS LOOK TO BE ON TRACK FOR TODAY...WITH HIGHS IN THE UPPER
40S NEAR THE LAKE AND MID 50S WELL INLAND. MODIFIED CLOUD COVER A
BIT FOR TODAY BUT OTHERWISE NO MAJOR CHANGES TO THE GOING FORECAST.
STILL EXPECTING MID CLOUDS TO SPREAD INTO SOUTH CENTRAL WI THIS
EVENING AS LOW PRESSURE TRACKS FROM MN TO EASTERN IOWA. 12Z MODEL
GUIDANCE IS CONTINUING TO KEEP CHANCES FOR RAIN WITH THAT SYSTEM
VERY SLIM IN THE WESTERN FORECAST AREA TONIGHT. MAY BE ABLE TO CUT
BACK ON THOSE SMALL CHANCES EVEN MORE.
&&
.AVIATION/18Z TAFS/...
LAKE CLOUDS WILL SPREAD INLAND TO THE KETTLE MORRAINE LATE THIS
MORNING...THEN GRADUALLY MIX OUT BY OR SHORTLY AFTER NOON. DIURNAL
CUMULUS CLOUDS SHOULD DEVELOP INLAND THIS AFTERNOON. UNCERTAINTY OF
BROKEN OR SCATTERED...BUT THEY WILL BE WELL INTO THE VFR CATEGORY.
LOW PRESSURE WILL CROSS MN AND EASTERN IOWA TODAY AND TONIGHT. MID
CLOUDS MAY SPREAD INTO SOUTH CENTRAL WI AND REACH MSN THIS
EVENING...BUT PRECIP CHANCES WILL BE IN FAR WESTERN WI AND TAF SITES
WILL REMAIN DRY THROUGH THE PERIOD DUE TO THE DRY EASTERLY FLOW AND
HIGH PRESSURE RIDGE IN PLACE.
CHANCE FOR VFR BROKEN DIURNAL CUMULUS CLOUDS ONCE AGAIN SUNDAY SOUTH
CENTRAL. NORTHEAST TO EAST WINDS WILL BE A LITTLE HIGHER NEAR THE
SHORELINE ON SUNDAY THAN TODAY.
&&
.PREV DISCUSSION... /ISSUED 331 AM CDT SAT APR 21 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
TEMPERATURES HAVE NOT FALLEN OFF AS QUICKLY AS EXPECTED...AND WITH
CLOUDS MOVING IN...DO NO THINK WE WILL RADIATE OUT TO 28F OR LESS
SO WILL CANCEL THE FREEZE WARNING.
BETTER PRECIPITATION CHANCES TIED TO SURFACE MOISTURE AXIS ALONG AND
JUST TO THE EAST OF THE TRACK OF THE SURFACE LOW...AND 850-700MB
LAYER FRONTOGENETIC FORCING AND ISENTROPIC LIFT OVER BAROCLINIC ZONE
THAT STAYS ALONG AND WEST OF THE MISSISSIPPI RIVER TODAY AND
TONIGHT. HIGHEST 850-700 MB Q-VECTOR CONVERGENCE REFLECTING WARM AIR
ADVECTION AS MAIN CONTRIBUTOR IN THIS LAYER WITH FOCUSED
CROSS-ISOTHERM FLOW JUST AHEAD OF SHORT WAVE. WILL LIMIT SLIGHT
CHANCE/CHANCE POPS TO FAR WEST.
SOME OMEGA ABOVE 600 MB OVER THE REMAINDER OF SOUTHERN WISCONSIN
CENTERED AROUND 00Z SUNDAY WITH WEAK UPPER DIVERGENCE WITH LEFT EXIT
REGION NOTED ON GFS AROUND 00Z SUNDAY...AS WELL AS Q-VECTOR
CONVERGENCE ABOVE 700 MB DUE TO DIFFERENTIAL VORTICITY ADVECTION.
HOWEVER DRY EASTERLY FLOW KEEPS LAYER BELOW 800 MB DRY AS FAR WEST
AS MADISON WITH LIFT DROPPING SOUTH OUT OF THE STATE BY MID-EVENING.
NORTHEAST TO EAST WINDS OFF THE LAKE WILL HOLD HIGHS IN THE MID TO
UPPER 40S EAST OF THE KETTLE MORAINE...WITH MODEL SOUNDINGS AND 925
MB TEMPERATURES SUPPORTING LOW TO MID 50S INLAND WITH THE WARMEST
TEMPERATURES IN THE WEST UNDER THE THERMAL RIDGE AHEAD OF THE SHORT
WAVE.
SUNDAY - CONFIDENCE...MEDIUM
LOW LEVEL EASTERLY FLOW BECOMES NORTHEAST WITH TIME. UPPER FLOW NNW
AND BROADLY CYCLONIC. DELTA T VALUES NOT HIGH ENOUGH TO GET EXCITED
ABOUT LAKE CLOUDS. WEAK RIPPLE IN THE FLOW. HARD TO LATCH ONTO MUCH
IN THE BUFKIT SOUNDINGS. MID LEVELS MOISTEN UP A BIT MORE SUNDAY
NIGHT. GUID POPS ARE SINGLE DIGITS AND WILL MAINTAIN DRY FORECAST.
MONDAY - CONFIDENCE...MEDIUM
A BIT MORE NVA BUILDS IN WITHIN THE NNW 500 MILLIBAR FLOW. 850 TEMPS
MODIFY A SMIDGE AND LOW LEVEL FLOW TURNS MORE NORTHWEST. GRADIENT
WEAK ENOUGH TO BELIEVE WINDS MAY BECOME ONSHORE.
TUESDAY AND WEDNESDAY - CONFIDENCE...LOW TO MEDIUM
BEST POTENTIAL FOR SOME UNSETTLED CONDITIONS. UPPER FLOW BECOMES
NORTHWEST AND WARM AIR ADVECTION INCREASES TUESDAY. 500 MILLIBAR
SHORT WAVE THEN AFFECTS THE AREA WEDNESDAY. BUFKIT SOUNDINGS DO NOT
LOOK OVERLY UNSTABLE AND GIVEN THE NORTHWEST FLOW AND AND LACK OF A
FAVORABLE MOISTURE RETURN INTO SOUTHERN WI THIS SEEMS REASONABLE.
BULK OF MODELS KEEP HEAVIEST PRECIP TO OUR SOUTH THE WAVE...THOUGH
00Z GEMNH A BIT MORE ROBUST FOR SRN WI.
THURSDAY - CONFIDENCE...LOW
NORTHWEST UPPER FLOW PERSISTS WITH 00Z ECMWF SUGGESTING A MUCH
SLOWER FROPA THAN WHAT THE GFS IS SUGGESTING. 5-7C DIFFERENCE IN 850
TEMPS. ECMWF DOES COOL THINGS DOWN THEN FOR THURSDAY NIGHT. APPEARS
TO BE A DRY DAY WHETHER LOOKING AT THE GFS OR ECMWF.
FRIDAY - CONFIDENCE...LOW
00Z ECMWF MUCH MORE AGGRESSIVE WITH RETURN WAA PRECIP. GFS HOLDS
THEN BACK FURTHER TO THE WEST. DPROG FOR THIS TIME FRAME SHOWS THE
GFS BEING A BIT MORE CONSISTENT WITH HIGH PRESSURE IN CONTROL...WHILE
THE ECMWF HAS BEEN A BIT MORE CHAOTIC. WILL STICK WITH THE QUIET
ALLBLEND POPS FOR NOW AND SEE IF THE ECMWF TAKES ON MORE OF A
CONSISTENT LOOK WITH THIS QUICK RETURN OF WAA PRECIP.
AVIATION/12Z TAFS/...WILL KEEP PRECIPITATION OUT OF TAF SITES WITH
SHORT WAVE AS BETTER FORCING AND SATURATION STAYS TO THE WEST
CLOSER TO THE MISSISSIPPI RIVER. WILL SEE AN INCREASE IN MID TO
HIGH LEVEL CLOUDS TODAY ...WITH SOME LOWER CU AT KMSN THIS EVENING
BUT REMAINING AT VFR LEVELS.
MARINE...WILL BE CANCELLING THE SMALL CRAFT ADVISORY FOR NORTHERN ZONES...
AND WILL PROBABLY END THE ADVISORY IN THE SOUTHERN ZONES EARLY AS
WINDS ARE EASING AND WAVES SUBSIDING A BIT FASTER THAN EARLIER
EXPECTED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...REM
SUNDAY THROUGH FRIDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
632 AM CDT SAT APR 21 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
342 AM CDT SAT APR 21 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES TODAY THROUGH
SUNDAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ACROSS MUCH OF THE WESTERN U.S....TROUGHING
ENCOMPASSING MUCH OF THE WESTERN GREAT LAKES REGION...AND AN UPPER
LOW NEAR THE SOUTHWEST LOUISIANA COAST. COMING INTO THE UPPER
TROUGHING WAS A SHORTWAVE OVER NORTHERN NORTH DAKOTA. A LARGE AMOUNT
OF MID AND HIGH CLOUDS WERE PRESENT AHEAD OF THE SHORTWAVE...
STREAMING INTO THE WESTERN PART OF THE FORECAST AREA. RADAR AND
SURFACE OBS SHOW SHOWERS OCCURRING ACROSS EASTERN NORTH DAKOTA...IN
AN AREA OF DPVA AHEAD OF THE SHORTWAVE...WARM ADVECTION NOTED BY
SOUTHWEST WINDS OF 20-25 KT AT 850MB ON ABR AND FGF RADARS...AND
UPPER DIVERGENCE IN THE LEFT EXIT REGION OF A 100 KT JET STREAK OVER
SOUTH DAKOTA. RUC CROSS-SECTIONS SHOW A NICE LOW TO MID-LEVEL
FRONTOGENESIS ZONE THERE TOO WITH A FRONTOLYSIS/FRONTOGENESIS
COUPLET. PRECIPITABLE WATER UP IN EASTERN NORTH DAKOTA AROUND 0.5
INCH PER 00Z SOUNDINGS FROM BIS AND ABR. CLOSER TO THE FORECAST
AREA...A SURFACE HIGH PRESSURE RIDGE IS IN PLACE. MAINLY CLEAR SKIES
UNTIL RECENTLY COMBINED WITH DRY AIR NOTED BY PRECIPITABLE WATER OF
0.24 INCHES ON THE 00Z GRB SOUNDING HAS ALLOWED TEMPERATURES TO DROP
INTO MOSTLY THE 30S...COLDEST OVER CENTRAL WISCONSIN WHERE A FEW
UPPER 20S HAVE OCCURRED.
REGARDING CURRENT FROST/FREEZE HEADLINES...HAVE DROPPED THE FROST
ADVISORY AS CLOUDS SEEM TO BE HAMPERING TEMPS FROM DROPPING ENOUGH
TO PRODUCE WIDESPREAD FROST. CONSIDERED DROPPING FREEZE WARNING TOO
GIVEN CURRENT READINGS...BUT WITH ONLY THE TYPICAL COLD SPOTS IN
CENTRAL WISCONSIN BELOW FREEZING...WILL LET IT CONTINUE FOR NOW.
TODAY AND TONIGHT...FOCUS IS ON THE SHORTWAVE OVER NORTH DAKOTA.
GOOD MODEL AGREEMENT EXISTS OF THE SHORTWAVE TRACKING SOUTHEAST INTO
WESTERN IOWA BY THIS EVENING AND INTO SOUTHERN ILLINOIS LATE
TONIGHT. LOW PRESSURE AREA ACCOMPANYING THE SHORTWAVE TAKES PRETTY
MUCH THE SAME TRACK...WITH AN INVERTED TROUGH LINGERING BACK INTO
SOUTHWEST MINNESOTA AT THE SURFACE AFTER IT PASSES. ALTHOUGH THE
SHORTWAVE AND SURFACE FEATURES ARE TRACKING WEST OF HERE...WE STILL
SEE 30-40 METER 500MB HEIGHT FALLS TODAY...UPPER DIVERGENCE IN THE
LEFT EXIT REGION OF THAT 100 KT JET THIS AFTERNOON...AND THAT
FRONTOGENESIS/FRONTOLYSIS COUPLET IN THE LOW TO MID LEVELS MOVE
THROUGH WESTERN SECTIONS OF THE FORECAST AREA THIS AFTERNOON AND
EVENING. WITH A SURGE OF PRECIPITABLE WATER ACCOMPANYING THE
SYSTEM...UP TO 0.5 INCH OR SO...PRECIPITATION SEEMS TO BE A PRETTY
GOOD BET. HAVE RAISED CHANCES UP TO 100 FOR LOCATIONS MAINLY WEST OF
THE MISSISSIPPI RIVER FOR THIS AFTERNOON AND EVENING. FOR LOCATIONS
NORTH AND EAST OF I-94...THEY ARE ON THE WRONG / SUBSIDENT SIDE OF
THE FRONTOGENETICAL CIRCULATION. THEREFORE...DRY CONDITIONS ARE
MOSTLY EXPECTED THERE. TOTAL QPF AMOUNTS COULD BE UPWARDS OF 0.30
INCHES...A FAR CRY FROM THURSDAY. LOOK FOR PRECIPITATION TO DIMINISH
AFTER MIDNIGHT AS FORCING WEAKENS AND/OR SHIFTS SOUTHEAST OF HERE.
WITH A LOT OF CLOUDS TODAY AND EVENTUALLY RAIN COMING IN THIS
AFTERNOON FOR SOME AREAS...AS WELL AS 850MB TEMPS OF 0 TO -2C...
EXPECTING COOLER TEMPERATURES TODAY. STAYED ON THE COOL SIDE OF
GUIDANCE OUT WEST THEN A BLEND ELSEWHERE. MAY SEE A LITTLE DROP IN
TEMPS IN THE AFTERNOON WHERE IT RAINS DUE TO EVAPORATIVE COOLING. A
BLEND OF GUIDANCE SEEMS REASONABLE FOR LOWS TONIGHT BEING UNDER
PERSISTENT CLOUDS.
SUNDAY AND SUNDAY NIGHT...500MB HEIGHTS PROGGED TO RISE OVER THE
FORECAST AREA DURING MUCH OF THIS PERIOD IN THE WAKE OF
TODAY/TONIGHTS SHORTWAVE...THOUGH SOLIDLY REMAINING IN NORTHWEST
FLOW ALOFT. AS THE HEIGHTS RISE...THE INVERTED TROUGH OVER SOUTHWEST
MINNESOTA WEAKENS AND PUSHES EAST TOWARDS THE MISSISSIPPI RIVER BY
00Z. LOW LEVEL CONVERGENCE ON THIS TROUGH IN CONJUNCTION WITH
DAYTIME HEATING COULD BE ENOUGH TO PRODUCE A FEW SHOWERS...THOUGH
CONFIDENCE IS PRETTY LOW GIVEN THAT CLOUD COVER MAY PERSIST THROUGH
MUCH OF THE DAY. PLUS...AN EASTERLY FLOW IS PROGGED TO DEVELOP OVER
WISCONSIN AHEAD OF HIGH PRESSURE DROPPING DOWN INTO LAKE SUPERIOR.
THIS EASTERLY FLOW WILL DRIVE DRY AIR INTO THE AREA. MOST MODELS
ARE EITHER DRY OR CLOSE TO IT WITH QPF FIELDS. THEREFORE...HAVE
REDUCED PRECIPITATION CHANCES BY 10 PERCENT AND SHIFTED THE MAX AREA
WESTWARD CLOSER TO THE INVERTED TROUGH. ANY PRECIP WILL END BY 00Z
MONDAY AS THE SURFACE RIDGE BUILDS INTO THE AREA. TEMPERATURES ARE A
LITTLE TRICKY FOR SUNDAY NIGHT AS MODELS NOW SUGGEST SOME CLOUDS
UP AROUND THE DULUTH AREA DROPPING SOUTH WITH THE SURFACE RIDGE. AS
SUCH...FOR NOW LEANED A LITTLE CLOSER TO A MODEL CONSENSUS...SAME
TOO FOR HIGHS ON SUNDAY. CERTAINLY IF WE CLEAR OUT MORE THAN
EXPECTED...FROST/FREEZE CONDITIONS MAY BECOME A WORRY FOR SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT...THE FORECAST AREA IS EXPECTED TO BE STUCK
BETWEEN STRONG RIDGING IN THE WESTERN U.S. AND DEEP TROUGHING OVER
THE EASTERN U.S.. THE POSITION FAVORS HIGH PRESSURE AT THE
SURFACE...WHICH HOLDS TRUE FOR THE DAY MONDAY. THERE ARE SUGGESTIONS
OF A SLIGHT EASTWARD PUSH OF THE UPPER RIDGE MONDAY NIGHT...WHICH IN
TURN CAUSES A WARM ADVECTION SURGE INTO THE FORECAST AREA. 850MB
TEMPS CLIMB FROM 2-4C AT 00Z TUESDAY TO 6-10C AT 12Z TUESDAY. THE
21.00Z GFS/NAM DEVELOP QPF WITH THIS SURGE OF WARM ADVECTION OVER
NORTHERN AND EASTERN WISCONSIN...POSSIBLY CLIPPING TAYLOR AND ADAMS
COUNTIES. FOR NOW HAVE DECIDED TO KEEP IT DRY IN AGREEMENT WITH THE
ECMWF AND PREVIOUS FORECASTS...THINKING TOO THAT THERE IS NOT MUCH
MOISTURE TO WORK WITH AFTER BEING UNDER THE SURFACE HIGH PRESSURE
RIDGE. SOMETHING TO WATCH...THOUGH. WITH MAINLY SUNNY SKIES ON
MONDAY AND THE WARMING 850MB TEMPS...DEEP MIXING SHOULD OCCUR WITH
HIGHS TOPPING OUT IN THE UPPER 50S/LOW 60S. INCREASING SOUTHWEST
FLOW AHEAD OF A SURFACE TROUGH DROPPING DOWN INTO NORTHERN WISCONSIN
MONDAY NIGHT AND THE WARMER 850MB TEMPS COMING IN SHOULD HELP TO
PRODUCE A WARMER NIGHT.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
342 AM CDT SAT APR 21 2012
BETTER AGREEMENT EXISTS WITH THE 21.00Z ECMWF/GFS/CANADIAN AND GFS
ENSEMBLES TODAY THAN SEEN YESTERDAY. THE WESTERN RIDGE AND EASTERN
TROUGH PATTERN SEEN RECENTLY LOOKS TO CONTINUE THROUGH MUCH OF THE
LONG TERM FORECAST...THOUGH TOWARDS FRIDAY SOME FAIRLY DEEP
TROUGHING DEVELOPS ALONG THE WEST COAST OF THE U.S. TO HELP PUSH
THAT WESTERN RIDGE EASTWARD. WE GET A BRIEF TASTE OF THE WARM AIR
OUT OF THE UPPER RIDGE TUESDAY AND TUESDAY NIGHT...AHEAD OF A LOW
PRESSURE AREA DEEPENING OVER THE DAKOTAS AND SLIDING DOWN INTO IOWA.
WARM ADVECTION AHEAD OF THIS LOW SHOULD PRODUCE SOME SHOWERS AND
POSSIBLY THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY. LOCATIONS WEST
OF THE MISSISSIPPI RIVER SEEM MOST FAVORABLE RIGHT NOW FOR
PRECIPITATION. HIGH PRESSURE THEN DROPS IN FROM CANADA FOR WEDNESDAY
NIGHT THROUGH FRIDAY NIGHT...WITH MAYBE A BRIEF DRY COLD FRONT
MOVING THROUGH BETWEEN THEN ON THURSDAY NIGHT. THEREFORE...WHEN IT
COMES TO TEMPERATURES...WARMEST READINGS ARE EXPECTED ON TUESDAY AND
WEDNESDAY. MAY HAVE TO DEAL WITH FROST/FREEZE CONDITIONS THURSDAY
NIGHT OR FRIDAY NIGHT OVER CENTRAL WISCONSIN. SOMETHING TO WATCH.
&&
.AVIATION...TODAY AND TONIGHT
632 AM CDT SAT APR 21 2012
SFC LOW AND MID LEVEL SHORTWAVE OVER THE EASTERN DAKOTAS THIS
MORNING WILL DROP SOUTHEAST ACROSS MN/IA TODAY/TONIGHT...ENDING UP
IN EASTERN MO BY 12Z SUN. MOISTURE/CLOUDS WILL INCREASE OVER THE
AREA TODAY AND CIGS WILL GRADUALLY LOWER THRU THE DAY. STRONGER
OF THE LOWER LEVEL FORCING/LIFT AND DEEPER MOISTURE WITH THIS SYSTEM
DROPS SOUTHEAST ACROSS MN INTO EASTERN IA TODAY/TONIGHT...STAYING
MAINLY ALONG/WEST OF THE MS RIVER. A DRIER SOUTHEAST SFC-925MB FLOW
PERSISTS ACROSS MUCH OF WI/IL EAST OF THE MS RIVER. THIS SETS UP
KLSE AS A BATTLE ZONE BETWEEN THE INCREASING MOISTURE/LIFT TO THE
WEST AND DRIER AIR TO THE EAST...MAKING FOR A MORE DIFFICULT...LOWER
CONFIDENCE TAF. DID BRING SOME -SHRA INTO KLSE FOR THE LATE
AFTERNOON/EVENING HOURS WITH MINOR VSBY RESTRICTION EARLY THIS
EVENING...WITH THE DRIER SFC-925MB FLOW EXPECTED TO KEEP THE CIGS
VFR AT KLSE. KRST ENDS UP UNDER SOME OF THE STRONGER LIFT/DEEPER
MOISTURE LATER THIS AFTERNOON/EVENING WITH MVFR CIGS/VSBYS EXPECTED
IN -SHRA/BR THRU THE LATE AFTERNOON/EVENING HOURS. THE STRONGER OF
THE LIFT PASSES SOUTH OF THE AREA AFTER MIDNIGHT WITH THE DRIER LOW
LEVEL EAST TO SOUTHEAST FLOW LOOKING TO THEN PUSH WESTWARD ACROSS
THE AREA...WITH IMPROVING CIGS/VSBYS OVERNIGHT INTO SUN MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CDT SAT APR 21 2012
WI...FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-034-
042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS ALBANY NY
149 PM EDT SAT APR 21 2012
.SYNOPSIS...
A MUCH NEEDED RAINFALL ON THE WAY. A COLD FRONT WILL GRADUALLY MOVE
EASTWARD ACROSS THE AREA TODAY...WHICH WILL BRING THE AREA ITS FIRST
WIDESPREAD MEASURABLE RAINFALL SINCE APRIL 1ST. AN AREA OF LOW
PRESSURE WILL APPROACH FROM THE SOUTH SUNDAY AND MOVE ACROSS THE
REGION MONDAY BRINGING A SOAKING RAINFALL.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM...CONVECTION IS DEVELOPING ACROSS EASTERN NY AS THIS
IS ALONG THE INSTABILITY GRADIENT PER THE HRRR/RUC13/LAPS. SURFACE
BASED PARCELS SUGGEST CAPES ARE APPROACHING 1K J/KG FROM THE
HUDSON RIVER VALLEY...INTO THE CATSKILLS. HRRR REFLECTIVITY IS
DOING VERY WELL AND EXPECTATION OF ADDITIONAL SCT-BKN LINE OF
CONVECTION TO SLOWLY MOVE ACROSS EASTERN NY COUNTIES THE REMAINDER
OF THE AFTERNOON. OTHERWISE...POST FRONTAL RAIN SHIELD WILL IMPACT
THE DACKS AND WESTERN MOHAWK VALLEY.
TEMPERATURE GRADIENT WILL BE QUITE IMPRESSIVE WITH TEMPERATURES
INTO THE UPPER 40S ACROSS PORTIONS OF THE DACKS WITH MID 70S INTO
THE MID HUDSON VALLEY AND LITCHFIELD COUNTY CT.
EXPECTING OUR FIRST WIDESPREAD MEASURABLE RAINFALL ACROSS THE
LOCAL AREA SINCE APRIL 1ST AS A COLD FRONTAL BOUNDARY GRADUALLY
MOVES EASTWARD ACROSS THE REGION. THIS BOUNDARY IS EXPECTED TO
BECOME NEARLY STATIONARY JUST OFFSHORE TONIGHT. THE ASSOCIATED
RAINFALL WILL OCCUR ALONG AND BEHIND THE BOUNDARY WITH WEAK WAVES
OF PRESSURE MOVE NORTHWARD ALONG IT. HAVE POPS DECREASING AFTER
MIDNIGHT TO UNDER LIKELY ACROSS ALL BUT THE SOUTHEAST PORTION OF
THE FORECAST AREA. EXPECTING 1/4 TO 3/4 INCHES OF RAINFALL TODAY
AND TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE TIMING AND TRACK ON THE
SURFACE LOW UP THE SOUTHEAST COAST ALONG THE STALLED BOUNDARY. THE
GFSENSEMBLE MEMBERS AND OPERATIONAL RUNS ARE TIGHTLY CLUSTERED ALONG
THE MID ATLANTIC COAST SUNDAY NIGHT AND BRING THE LOW OVER NEW YORK
CITY MONDAY MORNING. THE ENSEMBLE SPREAD THEN INCREASES AS THE LOW
HEADS NORTH-NORTHWESTWARD ACROSS NEW YORK STATE MONDAY AFTERNOON AND
NIGHT AS ITS DRAWN UNDER THE UPPER LOW WHICH DEVELOPS OVER THE OHIO
VALLEY BY SUNDAY EVENING.
LULL IN THE RAINFALL IS EXPECTED SUNDAY MORNING ACROSS MOST OF THE
FORECAST AREA...ESPECIALLY THE NORTHERN AND WESTERN PORTIONS.
HOWEVER...THE RAIN WILL SPREAD BACK NORTHWARD SUNDAY AFTERNOON
BECOMING HEAVY AT TIMES SUNDAY EVENING AS THE SURFACE LOW APPROACHES
AND ITS ASSOCIATED STRONG LOW LEVEL JET MOVES INTO THE REGION.
AT THIS TIME...THE THERMAL PROFILES WILL SUPPORT SNOW ACROSS SOME OF
THE HIGHER TERRAIN OF THE FORECAST AREA SUNDAY NIGHT (MAINLY AFTER
MIDNIGHT) INTO EARLY MONDAY MORNING. MAINLY ABOVE 1500 FEET AND
PARTICULARLY ACROSS THE SOUTHERN ADIRONDACKS WHERE A LIGHT
ACCUMULATION IS POSSIBLE.
THE RAIN WILL LIGHTEN UP ON MONDAY AS THE LOW PASSES OVER THE AREA.
THE SYSTEM IS EXPECTED TO BECOME VERTICALLY STACKED MONDAY NIGHT AS
IT HEADS INTO CANADA.
AN ADDITIONAL 1 TO 3 INCHES OF RAINFALL IS EXPECTED WITH THE LOW
SUNDAY THROUGH MONDAY.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE EXTENDED FORECAST PERIOD BEGINS WITH THE OCCLUDED CYCLONE
RESPONSIBLE FOR ALL THE ACTIVE WEATHER IN THE SHORT TERM SLOWLY
LIFTING N/NE INTO SE ONTARIO...AND SW QUEBEC. SHORT-WAVE ENERGY WILL
CONTINUE TO PIVOT AROUND THE UPPER LEVEL LOW WITH A MIX OF RAIN AND
SNOW SHOWERS IN THE MORNING. THE BETTER COLD AIR ADVECTION...AND
STEEPER LAPSE RATES ASSOCIATED WITH THE MID LEVEL COLD POOL ALOFT
WILL BE FROM THE HUDSON RIVER VALLEY WESTWARD. SOME LIGHT SNOW
ACCUMULATIONS OF A COATING TO AN INCH OR TWO IN THE MOUNTAINS...AND
ON THE GRASSY SURFACES IN THE VALLEYS...WILL BE POSSIBLE WEST OF
ALBANY. INSTABILITY SHOWERS WILL CONTINUE INTO THE AFTERNOON WITH
HIGHS IN U40S TO M50S OVER THE VALLEYS AND HILLS...AND U30S TO U40S
OVER THE MTNS.
TUESDAY NIGHT INTO WEDNESDAY...THE STACKED SYSTEM CONTINUES TO LIFT
AND MIGRATE N/NW TOWARDS JAMES BAY. A SERIES OF SFC TROUGHS WILL
MOVE ACROSS THE REGION WITH THE THREAT OF RAIN/SNOW SHOWERS AT
NIGHT...WITH THE BETTER CHC OF SNOW SHOWERS OVER THE MTNS...AND A
CHANCE OF SHOWERS DURING THE DAY. THE REGION WILL BE UNDER THE
INFLUENCE OF W/NW FLOW ALOFT...BUT LOW AND MID LEVEL TEMPS SLIGHTLY
MODERATE WITH H850 TEMPS RISING ABOVE 0C ACROSS MOST OF THE FCST
AREA BY WED PM...AND WITH A LATE APRIL SUN ANGLE...DOWNSLOPING AND
DEEPER MIXING...MAX TEMPS COULD REBOUND INTO THE MID 50S TO NEAR 60F
FROM THE CAPITAL REGION SOUTH AND EAST OVER THE BERKS...LITCHFIELD
HILLS...AND MID HUDSON VALLEY...WITH M40S TO L50S NORTH AND WEST OF
THE THE TRI CITIES. THIS WILL BE AFTER A CHILLY START WITH TEMPS IN
THE U20S TO L30S OVER THE MTNS...AND MID TO U30S IN THE VALLEYS.
WEDNESDAY NIGHT INTO FRIDAY...THE BROAD NEGATIVELY TILTED UPPER
TROUGH OVER THE EAST COAST WEAKENS...AS THE MID LEVEL FLOW FLATTENS
AND BECOMES MORE ZONAL BRIEFLY WED NIGHT INTO EARLY THU...AS A
CLIPPER LOW APPROACHES FROM THE MIDWEST. THE MEDIUM RANGE GUIDANCE
DIVERGENCES ON THE TIMING AND PLACEMENT OF THIS SYSTEM FOR THU. THE
ECMWF IS MUCH FURTHER SOUTH THAN THE GFS. THE GFS AMPLIFIES THE
LONGWAVE UPPER TROUGH...AS THE SFC WAVE LIFTS N/NE TOWARDS LONG
ISLAND...AND SRN NEW ENGLAND BY 12Z THU. CRITICAL THICKNESSES AND
THERMAL PROFILES INDICATE MAINLY RAIN FOR THE LOWER
ELEVATIONS...THOUGH SOME WET SNOW MAY BE POSSIBLE OVER THE HIGHER
TERRAIN...ONCE AGAIN...IF THE GFS IS RIGHT WITH THE PLACEMENT AND
TRACK. HPC LEANED CLOSER TO THE GFS...AND WE HAVE SIDED WITH IT FOR
NOW. THURSDAY NIGHT INTO FRIDAY...THE SFC WAVE DEEPENS AND
INTENSIFIES OVER THE CANADIAN MARITIMES...AS THE LONGWAVE TROUGH
AMPLIFIES OVER THE NORTHEAST...GREAT LAKES REGION...AND SE CANADA.
A CHILLY CANADIAN HIGH STARTS TO RIDGE IN FROM THE W-CNTRL GREAT
LAKES REGION TO CLOSE THE WEEK. THERE IS MAINLY A SLIGHT CHC OF A
SHOWER WITH AN UPPER LEVEL DISTURBANCE MOVING THROUGH ON FRI WHICH
WILL BE IN THE GRIDDED FCSTS. TEMPS DURING THIS TIME FRAME WILL BE
RUNNING A LITTLE COLDER THAN NORMAL WITH 50S TO L60S IN THE
VALLEYS...AND 40S TO L50S OVER THE MTNS. LOWS WILL BE IN THE U20S TO
30S FOR ERN NY AND WRN NEW ENGLAND.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A COLD FRONT WILL SLOWLY MOVE S/SE ACROSS THE REGION THROUGH THIS
EVENING WITH A WAVE OF LOW PRESSURE MOVING ALONG IT BRINGING
RAIN...HEAVY AT TIMES...TO THE REGION THROUGH MUCH OF TONIGHT.
VFR CONDITIONS THROUGH MUCH OF THIS AFTERNOON AT THE TAF SITES WILL
GIVE WAY TO MVFR/IFR CONDITIONS TONIGHT WITH A RETURN TO VFR
CONDITIONS FOR A TIME AROUND MID MORNING ON SUNDAY. STRONG LOW-LEVEL
CONVERGENCE ALONG THE FRONT WILL CONTINUE TO INCREASES THE CHANCE
OF RAIN STARTING AT KGFL ARND 18Z...KALB ARND 20Z AND KPOU BTWN 22Z
AND 00Z. THERE IS A POSSIBILITY OF ISOLATE THUNDERSTORMS...HOWEVER
PROBABILITY LOW ENOUGH TO LEAVE OUT OF THE TAFS AT THIS TIME. IN THE
WAKE OF THE COLD FRONT THE WINDS ARE EXPECTED TO SHIFT FROM S/SW TO
W/NW. AFTER 00Z...THE WINDS WILL CONTINUE TO VEER TO THE N/NW WITH A
STEADIER BAND OF RAIN.
THE WINDS WILL BE FROM THE S/SW AT AROUND 10 KTS UNTIL LATE THIS
AFTERNOON. THE WINDS WILL SHIFT TO W/NW AT 8-12 KTS LATE THIS
AFTERNOON...AND GENERALLY BE AROUND 10 KTS OR LESS OVERNIGHT INTO
SUNDAY MORNING.
.OUTLOOK...
SUN AFT-MON...VFR/MVFR...CHC IFR IN RAIN/HVY RAIN.
MON NT-WED NT...VFR/MVFR...CHC -SHRAS.
THU...VFR. NO SIG WX.
&&
.FIRE WEATHER...
A MUCH NEEDED RAINFALL ON THE WAY. A COLD FRONT WILL GRADUALLY MOVE
EASTWARD ACROSS THE AREA TODAY...WHICH WILL BRING THE AREA ITS FIRST
WIDESPREAD MEASURABLE RAINFALL SINCE APRIL 1ST. AN AREA OF LOW
PRESSURE WILL APPROACH FROM THE SOUTH SUNDAY AND MOVE ACROSS THE
REGION MONDAY BRINGING A SOAKING RAINFALL.
&&
.HYDROLOGY...
MUCH NEEDED RAINFALL ON THE WAY WHICH HELP TO ALLEVIATE DROUGHT
CONDITIONS. A COLD FRONT WILL GRADUALLY MOVE EASTWARD ACROSS THE
AREA TODAY...WHICH WILL BRING THE AREA ITS FIRST WIDESPREAD
MEASURABLE RAINFALL SINCE APRIL 1ST. AN AREA OF LOW PRESSURE WILL
APPROACH FROM THE SOUTH SUNDAY AND MOVE ACROSS THE REGION MONDAY
BRINGING A SOAKING RAINFALL.
PRECIPITATION ASSOCIATED WITH THE PASSAGE OF THE FRONTAL BOUNDARY
TODAY AND TONIGHT IS EXPECTED TO BE 1/4 TO 3/4 INCHES. THE
PRECIPITATION ASSOCIATED WITH THE AREA OF LOW PRESSURE SUNDAY INTO
MONDAY IS EXPECTED TO BE 1 TO 3 INCHES. THE HIGHEST PRECIPITATION
RAINFALL AMOUNTS EXPECTED SOUTH AND EAST OF THE CAPITAL DISTRICT
ESPECIALLY ACROSS LITCHFIELD COUNTY.
ANTECEDENT CONDITIONS ARE VERY DRY...PRECIPITATION DEFICITS ARE
RUNNING 5 TO 10 INCHES BELOW NORMAL ACROSS EASTERN NEW YORK AND
WESTERN NEW ENGLAND. STREAMFLOW CONDITIONS ARE AT WELL BELOW NORMAL
AND RESERVOIR LEVELS ACROSS THE AREA REMAIN NEAR TO SLIGHTLY BELOW
NORMAL. THE FORECAST RAINFALL AMOUNTS ARE EXPECTED TO PRODUCE
SIGNIFICANT WITHIN BANK RISES WITH SOME MINOR FLOODING A
POSSIBILITY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
PRECIPITATION (DEPARTURE FROM NORMAL)
ALBANY NY:
MONTH TO DATE THROUGH THE 20TH: 0.14 INCHES (-2.00 INCHES)
SINCE MAR 1: 1.68 INCHES (-3.67 INCHES)
SINCE JAN 1: 4.94 INCHES (-5.20 INCHES)
GLENS FALLS NY:
MONTH TO DATE THROUGH THE 20TH: 0.32 INCHES (-1.63 INCHES)
SINCE MAR 1: 1.55 INCHES (-3.34 INCHES)
SINCE JAN 1: 4.49 INCHES (-5.34 INCHES)
POUGHKEEPSIE NY:
MONTH TO DATE THROUGH THE 20TH: 0.26 INCHES (-2.27 INCHES)
SINCE MAR 1: 1.45 INCHES (-4.65 INCHES)
SINCE JAN 1: 5.06 INCHES (-6.78 INCHES)
BENNINGTON VT:
MONTH TO DATE THROUGH THE 20TH: 0.47 INCHES (-1.79 INCHES)
SINCE MAR 1: 2.05 INCHES (-3.36 INCHES)
SINCE JAN 1: 4.55 INCHES (-5.85 INCHES)
PITTSFIELD MA:
MONTH TO DATE THROUGH THE 20TH: 0.38 INCHES (-2.47 INCHES)
SINCE MAR 1: 1.52 INCHES (-4.70 INCHES)
SINCE JAN 1: 5.73 INCHES (-6.09 INCHES)
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/BGM/11
SHORT TERM...IAA
LONG TERM...WASULA
AVIATION...11
FIRE WEATHER...IAA
HYDROLOGY...IAA
CLIMATE...IAA
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS DES MOINES IA
310 PM CDT SAT APR 21 2012
.SHORT TERM /TONIGHT/...
PRIMARY CONCERN TONIGHT WILL BE THE EVOLUTION OF UPSTREAM SHORT
WAVE/PV ANOMALY...WHICH MODELS BRING RIGHT THROUGH IA LATER
TONIGHT. CURRENT MORE THERMODYNAMICALLY FORCED BAND OF PRECIP
SHOULD EXIT ERN FORECAST AREA BY 00Z FOLLOWED BY LINE OF SCATTERED
SHOWERS/STORMS FOCUSED ON LOW LEVEL CONVERGENCE WITH PASSAGE OF
TROUGH. 20Z SURFACE ANALYSIS PLACES ACTUAL COLD FRONT FROM LOW NEAR
FARGO BACK ALONG ND/SD BORDER. COULD SEE SOME BELOW SEVERE CRITERIA
HAIL/WIND WITH THESE STORMS NW...BUT DECREASING/INCREASING
MLCAPE/CIN RESPECTIVELY SHOULD GRADUALLY WEAKEN STORMS AS THEY GET
INTO CENTRAL IA. RUC MLCAPE APPEARS TO PEAK AT NO MORE THAN 300
J/KG AS IT ENTER FORECAST AREA. ATTENTION WILL THEN TURNS TO
FORCING AND MOISTURE 3KM AND BELOW ASSOCIATED WITH PASSAGE OF SHORT
WAVE WHICH MAINLY APPEARS TO AFFECT NERN HALF OF IA. HAVE HIGH
CHANCE/LIKELY POPS TONIGHT IN THESE AREAS...BUT FEEL THIS WILL BE
FOR A TRANSIENT LOW QPF EVENT.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
AMPLIFIED UPPER PATTERN OVER THE CONUS EARLY NEXT WEEK WITH UPPER
RIDGE CENTERED OVER THE CENTRAL ROCKIES AND A DEEP UPPER TROUGH OVER
THE EASTERN UNITED STATES. SHORTWAVE OVER THE UPPER MIDWEST TODAY IS
FORECAST TO CURVE OUT A DEEP UPPER LOW CENTERED NEAR THE EAST COAST
BY MONDAY. THIS WILL LEAVE CENTRAL IOWA IN INITIALLY NORTHERLY
UPPER FLOW WHICH SHOULD SLOWLY BECOME NORTHWESTERLY BY
TUESDAY/WEDNESDAY AS A SHORTWAVE FLATTENS THE UPPER RIDGE TO THE
WEST. THE MODELS SEEM TO BE IN FAIR AGREEMENT WITH THE GENERAL UPPER
PATTERN...BUT THERE ARE DIFFERENCES MID WEEK CONCERNING THE PASSAGE
OF A SIGNIFICANT COLD FRONT. THE 12Z OPERATIONAL GFS BRINGS A
STRONG CANADIAN HIGH DOWN INTO THE UPPER MIDWEST DURING THE
WEDNESDAY THROUGH FRIDAY TIME PERIOD. THE 12Z ECMWF IS SIMILAR TO
THE 12Z GFS CONCERNING THE PLACEMENT AND STRENGTH OF THE CANADIAN
HIGH.
12Z NAM/GFS BOTH LINGER PRECIPITATION OVER CENTRAL IOWA ON SUNDAY IN
THE VICINITY OF AN INVERTED TROUGH. THE TROUGH SHOULD WEAKEN DURING
THE DAY AS THE SURFACE RIDGE BUILDS IN. EXPECT CLOUDS ON SUNDAY
WITH SMALL SHOWER CHANCES THROUGH NOON. SKIES SHOULD CLEAR SUNDAY
NIGHT UNDER APPROACHING HIGH ALLOWING TEMPERATURES TO FALL NEAR
FREEZING IN SPOTS. CONDITIONS SHOULD BE FAVORABLE FOR FROST...LIGHT
WINDS AND CLEAR SKIES.
AS THE UPPER FLOW FLATTENS BY TUESDAY AND SURFACE AND LOW-LEVEL FLOW
BECOMES WEST SOUTHWEST WITH STRONG WARM ADVECTION...EXPECT
TEMPERATURES TO WARM INTO THE 80S OVER WESTERN IOWA.
MODEL UNCERTAINTY IN THE LONG RANGE...DAY SIX AND SEVEN...WILL
RESULT IN MODERATE POPS. NEXT WESTERN CONUS UPPER TROUGH AND
ACCOMPANYING SURFACE FEATURES SHOULD IMPACT CENTRAL IOWA DURING THIS
TIME PERIOD. IN ALL CASES...THE PATTERN SHOULD BECOME FAVORABLE FOR
THUNDERSTORMS BY THE END OF THE FORECAST PERIOD.
&&
.AVIATION...21/18Z
BAND OF SHOWERS WITH MAINLY LOW VFR CIGS MOVING ACROSS ERN HALF OF
IA EARLY THIS AFTERNOON. THERE ARE A FEW SMALL PATCHES OF MVFR CIGS
AND MAY AFFECT KALO AS WELL. PARENT UPPER LOW IS STILL ALONG ND/MN
BORDER HOWEVER AND MOVING SE SO AFFECTS OF THIS SYSTEM WILL LINGER
INTO SUN. PRECIP TRENDS UNCERTAIN AND DO NOT WANT TO CARRY A LONG
PERIOD UNNECESSARILY SO NOTHING MORE THAN VCSH WORDING LATER TODAY
AND TONIGHT...MOST LIKELY PERIOD...UNTIL TRENDS BECOME CLEARER.
THERE ARE SOME MINIMAL THUNDER CHANCES BUT NOT ENOUGH TO MENTION
YET. EXPECT CIGS TO LIFT TOWARD THE END OF THE PERIOD AS SYSTEMS
EXIT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...JOHNSON
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
652 PM EDT SAT APR 21 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 425 PM EDT SAT APR 21 2012
THE AMPLIFYING RIDGE OVER THE WRN CONUS AND THE STRENGTHENING UPPER
LOW OVER THE GULF WILL LEAD TO THE NRN STREAM TROUGH AMPLIFYING
OVER THE UPPER GREAT LKS. THIS WILL ALLOW THE NRN STREAM JET TO
STRETCH FROM SASK/ALBERTA SE INTO THE SE CONUS. WITH THIS
AMPLIFICATION AND THE SHORTWAVE NOW PUSHING INTO WRN MN AND SE INTO
ILLINOIS TONIGHT...EXPECT THE SFC LOW AND ASSOCIATED WARM FRONT PCPN
OVER WRN MN TO FOCUS FARTHER S...WHILE H850-700 WAA PCPN OVER
NERN MN WILL DIMINISH WITH THE WEAKENING LOW/WAA. THIS REFOCUSING TO
THE SE IS SEEN WELL IN THE NAM/GFS H850-500 Q-VECTOR CONV
AREAS...ALONG WITH THEIR MOISTURE FIELDS. 17Z RUC ALSO HAS A GOOD
HANDLE ON THE PCPN IN THE SHORT TERM AND WILL USE THOSE FOR THE
EVOLUTION THIS EVENING. ALL IN ALL...EXPECT THE PCPN TO STAY JUST W
OF THE CWA...DUE TO THE DRY SFC TO H850 AIR ROTATING AROUND THE
HIGH IN ONTARIO. BUT STILL EXPECT MID/HIGH CLOUDS TO CONTINUE TO
SLOWLY PUSH E OVER THE WRN THIRD OF THE CWA AND REMAIN THROUGH THE
NIGHT. ELSEWHERE...EXPECT THE DIURNAL CU TO DISSIPATE AND A MOSTLY
CLEAR NIGHT IS EXPECTED.
THE EXACT LOCATION OF THE CLOUDS WILL LARGELY DETERMINE TEMPS OVER
THE WRN HALF OF THE CWA. DID KEEP LOWS UP SOME WITH THE EXPECTED
CLOUD COVER...TOWARDS FREEZING OVER THE FAR W AND MID/UPPER 20S
TOWARDS THE W-CNTRL. LIGHT WINDS OVER THE CNTRL/EAST AND PWAT VALUES
OF 35-40 PERCENT OF NORMAL WILL LEAD TO A GOOD RADIATIONAL COOLING
NIGHT. HAVE LOWERED TEMPS OVER THE E BASED OFF LOWS LAST NIGHT AND
AFTN DEWPOINTS FALLING INTO THE UPPER TEENS AND LOWER 20S. WENT A
FEW DEGREES BELOW GUIDANCE OVER THE INTERIOR COLD SPOTS...MAINLY IN
THE LOWER 20S.
SUNDAY...SFC LOW WILL MOVE OUT OF THE GULF ON SUN AND UP THE
ATLANTIC SEABOARD...WHILE THE UPPER RIDGE CONTINUES TO AMPLIFY OVER
THE WRN CONUS AND CANADIAN ROCKIES. THIS WILL KEEP HIGH PRESSURE
OVER THE UPPER GREAT LKS REGION...ALTHOUGH IT WILL GRADUALLY WEAKEN
AS IT FOCUSES OVER WRN LK SUPERIOR. NAM/GFS/ECMWF SHOWING WEAK
SHORTWAVE AND PV LOBE MOVING ACROSS THE AREA DURING THE
MORNING...BUT DRY LOW LEVELS WILL LIMIT PCPN CHANCES OVER THE W.
MODELS CONSISTENT ON H850-500 MOISTURE TO BE STUCK OVER THE WRN
THIRD OF THE CWA TOMORROW...WHICH WITH LIGHT WINDS AT THAT
LEVEL...WENT WITH PARTLY-MOSTLY CLOUDY SKIES. ELSEWHERE...LLVLS ARE
STILL FAIRLY DRY WITH THE HIGH PRESSURE RIDGE...SO EXPECT A MOSTLY
SUNNY SKY. WITH THE SUN OVER THE CNTRL/EAST...EXPECT MIXING TO H800
AND HAVE BUMPED TEMPS UP A DEGREE OR TWO FROM THE GOING
FORECAST...WITH LOW 50S AWAY FROM LK SUPERIOR INFLUENCES. THE LIGHT
NRLY FLOW SHOULD ALLOW THE LK SUPERIOR BREEZE TO DOMINATE AND BRING
SLIGHTLY COOLER TEMPS NEAR LK SUPERIOR THROUGH THE AFTN.
SURPRISINGLY...MODELS NOT PICKING UP ON MUCH COOL DOWN UNTIL AFTER
21Z...SO WILL FOLLOW THAT TREND NEAR LK SUPERIOR FOR NOW.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 425 PM EDT SAT APR 21 2012
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT ON THE BIG PICTURE FOR
THE NEXT 7 DAYS AS PATTERN WILL FEATURE A WRN NAMERICA RIDGE AND
ERN TROF...RESULTING IN NW FLOW DOMINATING THE UPPER GREAT LAKES
REGION. ERN TROF WILL BE MOST AMPLIFIED MON/TUE...AND WRN RIDGE WILL
BEGIN TO DRIFT E DURING THE LAST HALF OF THE WEEK WITH AXIS REACHING
THE MISSISSIPPI VALLEY TO MANITOBA BY SAT. OVERALL...THIS IS A DRY
PATTERN FOR THE FCST AREA. PCPN CHANCES WILL BE LIMITED...AND IF
ANY PCPN OCCURS...IT WILL LIKELY BE LIGHT. NW FLOW SHOULD KEEP TEMPS
ON THE COOLER SIDE OF NORMAL AND PROBABLY TREND MORE BLO NORMAL
LATER IN THE WEEK AS ENERGY DROPPING INTO ERN TROF USHERS COLDER AIR
INTO THE UPPER LAKES. AFTN TEMPS NEAR LAKE SUPERIOR WILL BE CHILLY
WITH ONSHORE WINDS EVERY DAY.
BEGINNING SUN NIGHT THRU TUE...WITHIN THE DEEP ERN TROF...A
MID/UPPER LEVEL LOW WILL BE LIFTING N THRU THE CNTRL APPALACHIANS...
REACHING WRN NY EARLY TUE AND SW QUEBEC TUE EVENING. MEDIUM RANGE
GUIDANCE CONTINUES TO KEEP THIS SYSTEM FAR ENOUGH E SO THAT ITS
DEFORMATION PCPN SHIELD WILL NOT AFFECT THE FCST AREA. THREAT OF ANY
PCPN WOULD COME FROM SHORTWAVES DROPPING THRU THE AREA UNDER NW FLOW
AS THERMAL GRADIENT WILL BE TIGHTENING TOWARD THE UPPER LAKES MON
AND ESPECIALLY TUE. THE GFS/GLOBAL GEM ARE A LITTLE FARTHER E WITH
THE TIGHTER THERMAL GRADIENT THAN THE ECMWF. AS A RESULT...
GFS/GLOBAL GEM HAVE PCPN STREAKING ACROSS MAINLY WRN UPPER MI TUE.
AT THIS POINT...WILL CARRY DRY WEATHER SUN NIGHT THRU MON NIGHT THEN
MAINTAIN SLIGHT CHC POPS LATER TUE/TUE NIGHT OVER ALL BUT THE E.
TIMING/TRACKS OF SHORTWAVES DROPPING INTO THE ERN TROF REMAIN
UNCERTAIN MIDWEEK. THE LAST SEVERAL RUNS OF THE ECMWF HAD BEEN
INSISTENT ON DROPPING A STRONG SHORTWAVE INTO THE UPPER LAKES LATE
THU...BUT THE 12Z RUN IS BEGINNING TO TREND TOWARD THE FASTER
GFS/GLOBAL GEM IDEA. WHETHER THIS WAVE CAN LINK UP/DRAW TIGHT
THERMAL GRADIENT FARTHER NE LIKE THE GFS/GLOBAL GEM TO RESULT IN A
PERIOD OF PCPN ACROSS THE FCST AREA INTO WED REMAINS TO BE SEEN.
BEHIND THE WAVE...850MB TEMPS COULD FALL TO AROUND -10C THU/EARLY
FRI. MIGHT BE ENOUGH FOR A LITTLE LIGHT LES AT NIGHT/EARLY MORNING
IF AIRMASS IS NOT TOO DRY.
FRI INTO SAT...WITH MID/UPPER LEVEL RIDGE MOVING CLOSER TO THE UPPER
LAKES...ASSOCIATED SFC HIGH PRES WILL DOMINATE THE AREA. THIS WILL
KEEP DRY WEATHER INTO THE FIRST HALF OF THE WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 652 PM EDT SAT APR 21 2012
VFR CONDITIONS EXPECTED FOR THE TAF SITES THROUGH THE PERIOD...AS A
HIGH IN ONTARIO PUSHES DRY LOW LEVEL AIR INTO UPPER MICHIGAN.
MOISTURE FROM LOW CURRENTLY CENTERED OVER NW MN WILL BRUSH KIWD AND
POTENTIALLY KCMX THROUGH SUN...AS IT WEAKENS AND SLIDES SE THROUGH
SOUTHERN MN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 PM EDT SAT APR 21 2012
HIGH PRESSURE NEAR HUDSON BAY WILL KEEP LIGHT NORTHERLY WINDS OVER
MUCH OF LAKE SUPERIOR. A LOW PRESSURE SYSTEM OVER ERN ND IS EXPECTED
TO WEAKEN WHILE QUICKLY SLIDING SE TONIGHT. THIS WILL DIMINISH THE
NE WINDS OF 20-25KTS OVER FAR WRN LAKE SUPERIOR. EXPECT NORTHERLY
WINDS TO REMAIN BELOW 25KTS THROUGH THE FIRST PART OF NEXT WEEK...AS
A LOW PRESSURE SYSTEM MOVES UP THE ATLANTIC SEABOARD TOMORROW AND
INTO QUEBEC BY TUESDAY. COLDER AIR FILTERING INTO THE AREA TOWARDS
MID WEEK COULD LEAD TO SOME STRONGER NORTHERLY WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
427 PM EDT SAT APR 21 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 425 PM EDT SAT APR 21 2012
THE AMPLIFYING RIDGE OVER THE WRN CONUS AND THE STRENGTHENING UPPER
LOW OVER THE GULF WILL LEAD TO THE NRN STREAM TROUGH AMPLIFYING
OVER THE UPPER GREAT LKS. THIS WILL ALLOW THE NRN STREAM JET TO
STRETCH FROM SASK/ALBERTA SE INTO THE SE CONUS. WITH THIS
AMPLIFICATION AND THE SHORTWAVE NOW PUSHING INTO WRN MN AND SE INTO
ILLINOIS TONIGHT...EXPECT THE SFC LOW AND ASSOCIATED WARM FRONT PCPN
OVER WRN MN TO FOCUS FARTHER S...WHILE H850-700 WAA PCPN OVER
NERN MN WILL DIMINISH WITH THE WEAKENING LOW/WAA. THIS REFOCUSING TO
THE SE IS SEEN WELL IN THE NAM/GFS H850-500 Q-VECTOR CONV
AREAS...ALONG WITH THEIR MOISTURE FIELDS. 17Z RUC ALSO HAS A GOOD
HANDLE ON THE PCPN IN THE SHORT TERM AND WILL USE THOSE FOR THE
EVOLUTION THIS EVENING. ALL IN ALL...EXPECT THE PCPN TO STAY JUST W
OF THE CWA...DUE TO THE DRY SFC TO H850 AIR ROTATING AROUND THE
HIGH IN ONTARIO. BUT STILL EXPECT MID/HIGH CLOUDS TO CONTINUE TO
SLOWLY PUSH E OVER THE WRN THIRD OF THE CWA AND REMAIN THROUGH THE
NIGHT. ELSEWHERE...EXPECT THE DIURNAL CU TO DISSIPATE AND A MOSTLY
CLEAR NIGHT IS EXPECTED.
THE EXACT LOCATION OF THE CLOUDS WILL LARGELY DETERMINE TEMPS OVER
THE WRN HALF OF THE CWA. DID KEEP LOWS UP SOME WITH THE EXPECTED
CLOUD COVER...TOWARDS FREEZING OVER THE FAR W AND MID/UPPER 20S
TOWARDS THE W-CNTRL. LIGHT WINDS OVER THE CNTRL/EAST AND PWAT VALUES
OF 35-40 PERCENT OF NORMAL WILL LEAD TO A GOOD RADIATIONAL COOLING
NIGHT. HAVE LOWERED TEMPS OVER THE E BASED OFF LOWS LAST NIGHT AND
AFTN DEWPOINTS FALLING INTO THE UPPER TEENS AND LOWER 20S. WENT A
FEW DEGREES BELOW GUIDANCE OVER THE INTERIOR COLD SPOTS...MAINLY IN
THE LOWER 20S.
SUNDAY...SFC LOW WILL MOVE OUT OF THE GULF ON SUN AND UP THE
ATLANTIC SEABOARD...WHILE THE UPPER RIDGE CONTINUES TO AMPLIFY OVER
THE WRN CONUS AND CANADIAN ROCKIES. THIS WILL KEEP HIGH PRESSURE
OVER THE UPPER GREAT LKS REGION...ALTHOUGH IT WILL GRADUALLY WEAKEN
AS IT FOCUSES OVER WRN LK SUPERIOR. NAM/GFS/ECMWF SHOWING WEAK
SHORTWAVE AND PV LOBE MOVING ACROSS THE AREA DURING THE
MORNING...BUT DRY LOW LEVELS WILL LIMIT PCPN CHANCES OVER THE W.
MODELS CONSISTENT ON H850-500 MOISTURE TO BE STUCK OVER THE WRN
THIRD OF THE CWA TOMORROW...WHICH WITH LIGHT WINDS AT THAT
LEVEL...WENT WITH PARTLY-MOSTLY CLOUDY SKIES. ELSEWHERE...LLVLS ARE
STILL FAIRLY DRY WITH THE HIGH PRESSURE RIDGE...SO EXPECT A MOSTLY
SUNNY SKY. WITH THE SUN OVER THE CNTRL/EAST...EXPECT MIXING TO H800
AND HAVE BUMPED TEMPS UP A DEGREE OR TWO FROM THE GOING
FORECAST...WITH LOW 50S AWAY FROM LK SUPERIOR INFLUENCES. THE LIGHT
NRLY FLOW SHOULD ALLOW THE LK SUPERIOR BREEZE TO DOMINATE AND BRING
SLIGHTLY COOLER TEMPS NEAR LK SUPERIOR THROUGH THE AFTN.
SURPRISINGLY...MODELS NOT PICKING UP ON MUCH COOL DOWN UNTIL AFTER
21Z...SO WILL FOLLOW THAT TREND NEAR LK SUPERIOR FOR NOW.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 425 PM EDT SAT APR 21 2012
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT ON THE BIG PICTURE FOR
THE NEXT 7 DAYS AS PATTERN WILL FEATURE A WRN NAMERICA RIDGE AND
ERN TROF...RESULTING IN NW FLOW DOMINATING THE UPPER GREAT LAKES
REGION. ERN TROF WILL BE MOST AMPLIFIED MON/TUE...AND WRN RIDGE WILL
BEGIN TO DRIFT E DURING THE LAST HALF OF THE WEEK WITH AXIS REACHING
THE MISSISSIPPI VALLEY TO MANITOBA BY SAT. OVERALL...THIS IS A DRY
PATTERN FOR THE FCST AREA. PCPN CHANCES WILL BE LIMITED...AND IF
ANY PCPN OCCURS...IT WILL LIKELY BE LIGHT. NW FLOW SHOULD KEEP TEMPS
ON THE COOLER SIDE OF NORMAL AND PROBABLY TREND MORE BLO NORMAL
LATER IN THE WEEK AS ENERGY DROPPING INTO ERN TROF USHERS COLDER AIR
INTO THE UPPER LAKES. AFTN TEMPS NEAR LAKE SUPERIOR WILL BE CHILLY
WITH ONSHORE WINDS EVERY DAY.
BEGINNING SUN NIGHT THRU TUE...WITHIN THE DEEP ERN TROF...A
MID/UPPER LEVEL LOW WILL BE LIFTING N THRU THE CNTRL APPALACHIANS...
REACHING WRN NY EARLY TUE AND SW QUEBEC TUE EVENING. MEDIUM RANGE
GUIDANCE CONTINUES TO KEEP THIS SYSTEM FAR ENOUGH E SO THAT ITS
DEFORMATION PCPN SHIELD WILL NOT AFFECT THE FCST AREA. THREAT OF ANY
PCPN WOULD COME FROM SHORTWAVES DROPPING THRU THE AREA UNDER NW FLOW
AS THERMAL GRADIENT WILL BE TIGHTENING TOWARD THE UPPER LAKES MON
AND ESPECIALLY TUE. THE GFS/GLOBAL GEM ARE A LITTLE FARTHER E WITH
THE TIGHTER THERMAL GRADIENT THAN THE ECMWF. AS A RESULT...
GFS/GLOBAL GEM HAVE PCPN STREAKING ACROSS MAINLY WRN UPPER MI TUE.
AT THIS POINT...WILL CARRY DRY WEATHER SUN NIGHT THRU MON NIGHT THEN
MAINTAIN SLIGHT CHC POPS LATER TUE/TUE NIGHT OVER ALL BUT THE E.
TIMING/TRACKS OF SHORTWAVES DROPPING INTO THE ERN TROF REMAIN
UNCERTAIN MIDWEEK. THE LAST SEVERAL RUNS OF THE ECMWF HAD BEEN
INSISTENT ON DROPPING A STRONG SHORTWAVE INTO THE UPPER LAKES LATE
THU...BUT THE 12Z RUN IS BEGINNING TO TREND TOWARD THE FASTER
GFS/GLOBAL GEM IDEA. WHETHER THIS WAVE CAN LINK UP/DRAW TIGHT
THERMAL GRADIENT FARTHER NE LIKE THE GFS/GLOBAL GEM TO RESULT IN A
PERIOD OF PCPN ACROSS THE FCST AREA INTO WED REMAINS TO BE SEEN.
BEHIND THE WAVE...850MB TEMPS COULD FALL TO AROUND -10C THU/EARLY
FRI. MIGHT BE ENOUGH FOR A LITTLE LIGHT LES AT NIGHT/EARLY MORNING
IF AIRMASS IS NOT TOO DRY.
FRI INTO SAT...WITH MID/UPPER LEVEL RIDGE MOVING CLOSER TO THE UPPER
LAKES...ASSOCIATED SFC HIGH PRES WILL DOMINATE THE AREA. THIS WILL
KEEP DRY WEATHER INTO THE FIRST HALF OF THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 139 PM EDT SAT APR 21 2012
VFR CONDITIONS EXPECTED FOR THE TAF SITES THROUGH THE PERIOD...AS A
HIGH IN ONTARIO PUSHES DRY LOW LEVEL AIR INTO UPPER MICHIGAN.
MOISTURE FROM LOW CURRENTLY CENTERED OVER NW MN WILL BRUSH KIWD AND
POTENTIALLY KCMX THIS AFTN THROUGH SUN...AS IT WEAKENS AND SLIDES SE
THROUGH SOUTHERN MN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 425 PM EDT SAT APR 21 2012
HIGH PRESSURE NEAR HUDSON BAY WILL KEEP LIGHT NORTHERLY WINDS OVER
MUCH OF LAKE SUPERIOR. A LOW PRESSURE SYSTEM OVER ERN ND IS EXPECTED
TO WEAKEN WHILE QUICKLY SLIDING SE TONIGHT. THIS WILL DIMINISH THE
NE WINDS OF 20-25KTS OVER FAR WRN LAKE SUPERIOR. EXPECT NORTHERLY
WINDS TO REMAIN BELOW 25KTS THROUGH THE FIRST PART OF NEXT WEEK...AS
A LOW PRESSURE SYSTEM MOVES UP THE ATLANTIC SEABOARD TOMORROW AND
INTO QUEBEC BY TUESDAY. COLDER AIR FILTERING INTO THE AREA TOWARDS
MID WEEK COULD LEAD TO SOME STRONGER NORTHERLY WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
156 PM EDT SAT APR 21 2012
.SYNOPSIS...
A COLD FRONT WILL PUSH THROUGH THE AREA TODAY BRINGING COOLER AIR
AND RAIN TO THE AREA. THE FRONT WILL STALL ALONG THE EAST COAST
TONIGHT. A INTENSE LOW WILL MOVE UP THE EAST COAST SUNDAY, AND
INTO UPSTATE NEW YORK MONDAY. THIS LOW WILL SPREAD RAIN BACK INTO
THE AREA SUNDAY NIGHT INTO MONDAY NIGHT. COLD AIR OVER WESTERN AND
CENTRAL NEW YORK AND NORTHERN PENNSYLVANIA, MAY SWITCH THE RAIN
TO SNOW AND BRING THOSE AREAS A FEW INCHES OF ACCUMULATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...A COLD FRONT CONTINUES TO MARCH ACROSS THE CWA ATTM
WITH THE MAIN SHIELD OF RAIN BEHIND THE FRONT...AND ONLY ISOLATED
SHOWERS JUST AHEAD OF IT. TEMP CHANGES ARE SHARP WITH KITH AND
KSYR NOW INTO THE UPPER 40S BEHIND THE FRONT...WITH LOWER 60S AT
TOWANDA...BINGHAMTON...AND HAMILTON JUST AHEAD OF THE FRONT.
EXPECT TEMPS TO COOL BACK INTO THE 40S AND 50S WITH THE FROPA THIS
AFTERNOON EXCEPT FOR THE FAR SE WHICH WON`T SEE THE FRONT UNTIL
LATER IN THE DAY.
TRIMMED BACK RAIN CHANCES A BIT ON THE FRONT EDGE. IT APPEARS OUR
MOST STEADY RAIN WILL HANG ACROSS THE WESTERN PART OF THE CWA
THROUGH EARLY AFTERNOON AND NOT MAKE HUGE PROGRESS EAST UNTIL
LATER TODAY. WE STILL REMAIN IN SEE TEXT ACROSS THE EXTREME FAR
SOUTHEAST FOR SEVERE WEATHER. A MARINE LAYER WHICH IS IN THE
PROCESS OF BURNING OFF WILL PUT A DAMPER ON OUR CHANCES. THIS IS
SHOWN NICELY BY THE RUC SHOWING CAPES ONLY IN THE 100 - 300 J/KG
RANGE THIS AFTERNOON AT MSV. THE NAM IS A BIT HIGHER BUT BOTH
MODELS SHOW A BIT OF A CAP BETWEEN 5000 AND 1000 FEET...WHICH WILL
FURTHER LIMIT ACTIVITY. IF WE SEE ANY STORMS FORM...THE BEST
CHANCE WILL BE ACROSS OUR EXTREME FAR SOUTHEAST AND THE
POTENTIAL WILL MAINLY BE FOR WIND WITH AN INVERTED V SOUNDING.
IT APPEARS OUR CHANCES FOR RAIN GO DOWN SHARPLY AFTER 06Z TONIGHT
SO I MADE THE ENTIRE AREA DRY LATE TONIGHT INTO EARLY SUNDAY TO
SHOW A BREAK IN BETWEEN OUR TWO SYSTEMS. MORE ON THE NEXT SYSTEM
LATER THIS AFTERNOON.
4 AM UPDATE... BIG CHANGES TO OUR RECENT MILD DRY PATTERN.
FIRST WITH A COLD FRONT AND RAIN SHOWERS TODAY THEN A STACKED LOW
WITH SNOW AND RAIN FOR SUNDAY TO TUESDAY.
ATTM A NE TO SW COLD ANAFRONT IS ACROSS NRN AND WRN NY. THIS WILL
MOVE SLOWLY EAST TODAY AND TO THE EAST COAST TONIGHT. SHOWERS
BEHIND THE FRONT WILL MOVE INTO CENTRAL NY THIS MORNING THEN INTO
NE PA AND THE CATSKILLS THIS AFTN. HIGHS WILL BE JUST AHEAD OF THE
SFC FRONT. THE HIGHEST TEMPS WILL BE ACROSS THE FAR SE WITH U60S
AND L70S. IN THIS AREA SOME ATLANTIC MOISTURE CAUSING LOW CLOUDS
BUT THIS WILL EXIT SO THAT SOME SUN IS POSSIBLE MIDDAY. ALSO MODEST
LOW LEVEL INSTABILITY COULD CAUSE A THUNDERSTORM THIS AFTN.
IN CENT NY TEMPERATURES WILL NOT BE WARM ENOUGH FOR THUNDERSTORMS.
THIS AFTN TEMPERATURES FALL THROUGH THE 40S AND INTO THE 30S
TONIGHT. IN THE SE TEMPS FALL INTO THE 40S.
SHOWERS WILL END IN NY LATE TODAY AND IN NE PA AND SULLIVAN COUNTY
NY THIS EVENING. RAINFALL BEHIND THE FRONT WILL BE A QUARTER TO
HALF AN INCH. POSSIBLY SOME HIGHER AMOUNTS IN THUNDERSTORMS. WITH
IT BEING SO DRY THIS MONTH LITTLE WILL RUN OFF.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
4 AM UPDATE...
A STRONG STORM WILL MOVE OUT OF THE GULF OF MEXICO AND UP THE EAST
COAST SUNDAY. THE SFC LOW INTENSIFIES THE WHOLE WAY. A DEEP UPPER
LEVEL TROF CLOSES OFF OVER THE OHIO VALLEY CAUSING THE SFC LOW TO
TURN NORTH THEN NE INTO UPSTATE NY. MONDAY NIGHT THE UPPER AND
SURFACE LOWS BECOME STACKED AND MOVE SLOWLY NORTH INTO SE CANADA.
MODELS IN BETTER AGREEMENT NOW WITH A SFC TRACK UP THE HUDSON
VALLEY. CENTRAL NY AND NE PA COULD GET 1 TO 2 INCHES LIQUID WITH
THIS STORM. RAIN MOVES IN AHEAD OF THE LOW LATE SUNDAY AND SUNDAY
NIGHT TO COVER THE WHOLE AREA. TEMPERATURES ARE WARM ENOUGH TO
START AS RAIN BUT ACROSS THE HIGHER TERRAIN ESPECIALLY IN NY WEST
OF THE CATSKILLS IT WILL MIX WITH SNOW. THE FURTHER WEST YOU GO
THE COLDER IT WILL BE SO THE COLDEST AIR WILL BE IN STEUBEN
COUNTY. PRECIP SHOULD CHANGE TO JUST SNOW LATE SUNDAY NIGHT.
MIDDAY MONDAY DAYTIME HEATING WILL CAUSE MOST OF THE PRECIP TO
CHANGE TO RAIN BEFORE CHANGING BACK TO A MIX OR SNOW MONDAY NIGHT.
LOW LEVELS CLOSE TO FREEZING SO ELEVATION WILL BE A FACTOR TOO.
SURFACE TEMPERATURES MOSTLY IN THE 30S SUNDAY NIGHT TO MONDAY
NIGHT. WITH THE WARMEST AIR OVER THE CATSKILLS AND POCONOS SNOW
AMOUNTS THERE ARE EXPECTED TO BE LESS THAN AN INCH. HIGH TEMPS
SUNDAY IN THE 50S AND AROUND 50 MONDAY. THE HIGHEST AMOUNTS OF
SEVERAL INCHES WILL BE ACROSS THE HIGHER TERRAIN IN CORTLAND
COUNTY...THE CENTRAL SOUTHERN TIER AND FINGER LAKES OF NY...AND
BRADFORD COUNTY PA. IN WESTERN STEUBEN COUNTY 6 TO 12 IS POSSIBLE.
EVEN WITH 1 TO 2 INCHES OF LIQUID RIVERS ARE NOT EXPECTED TO
FLOOD. VERY LOW RIVER LEVELS FOR APRIL. WILL NEED TO WATCH THE
DELAWARE BASINS SUNDAY NIGHT TO MONDAY WITH UP TO ONE INCH EACH 6
HOURS WITH TOTALS AROUND 3 INCHES. THIS AMOUNT WILL CAUSE RAPID
RISES ON THE STREAMS AND CREEKS. ONCE THE SFC LOW PASSES MONDAY
RAIN WILL END IN MOST OF NE PA AND THE CATSKILLS FOR MONDAY NIGHT.
WRAPAROUND MIXED PRECIP WILL CONTINUE IN CENTRAL AND WRN NY MONDAY
TO TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
UPR LOW CONTS TO LFT SLOWLY NORTH AT THE BEGINNING OF THE PD BUT
THE FCST AREA REMAINS IN A BROAD UPR TROF WITH COOL AND DAMP
CONDS. SHRT WV DROPS INTO THE TROF LATE THU AND EARLY FRI WHICH
WILL INCRS THE CHANCE OF SHWRS. DRIER AIR ARRIVES FOR SAT BUT
MODELS SHOW A WRM FNT DVLPG OVER THE OH VLY AND PUSHING NORTH.
THIS SHD NOT GENERATE MUCH PCPN...BUT CONTD CLDS SEEM LIKELY WITH
THE FNT.
TEMPS WILL GNRLY BE BLOW NRML THU THE PD...LEADING TO A CHANCE OF
SOME SNOW MIXED IN THE WITH SHWRS...PRIMARILY LTR AT NGT AND EARLY
MRNG AS THE TEMPS HIT THEIR LOWS. NOT ENUF COLD AIR FOR ANY CNCRN
FOR ACCUMS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
COLD FNT CUTTING THRU THE ERN AREAS ATTM WITH ONLY AVP STILL ON
THE WRM SIDE. THERE IS THE THREAT OF A TRW FOR THENEXT FEW HRS AT
AVP UNTIL THE FNT PASSES ARND 22Z. BHD THE FNT IS A BRK BUT BACK
IN THE COLD AIR ABAND OF MAINLY LGT PCPN WITH MVFR AND IFR CIGS
AND VSBYS. PCPN SHD END IN MOPST AREAS SHRTLY AFT 00Z...BUT VERY
STABLE AND WET SNDG WILL KEEP LOW CLDS AND SOME VSBY RESTRICTIONS
IN THRU THE NGT. DRIER AIR BEGINS TO PUSH IN AFT 12Z SUN...ESP IN
THE NORTH SO HAVE FCSTD RISING CIGS AND VSBYS FOR THE END OF THE
TAF PD. SW WINDS AHD OF THE FNT AT AVP OTRW A LGT NLY FLOW IS
XPCTD BHD THE FNT THRU THE END OF THE PD.
.OUTLOOK...
SUN AFTN...MAINLY VFR.
SUN NGT-MON...MVFR AND IFR IN RA.
TUE INTO THU...VFR/MVFR BUT ISTLD IFR PSBL IN SCT RAIN AND NSOW
SHWRS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TAC
NEAR TERM...HEDEN/TAC
SHORT TERM...TAC
LONG TERM...DGM
AVIATION...DGM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1210 PM CDT SAT APR 21 2012
.DISCUSSION...SEE 18Z AVIATION DISCUSSION AND MARINE UPDATE. NO
CHANGES NEEDED AT THIS TIME TO PUBLIC PRODUCTS.
&&
.AVIATION...P6SM SKC. NORTH WINDS DIMINISH AROUND SUNSET THEN
BECOMING EASTERLY DURING THE PERIOD...FIRST AT KLRD THEN ELSEWEHRE
BUT WINDS BELOW 11 KNOTS. NOT MUCH ELSE TO SAY. GFS-MOS SHOWING
4SM BR AT KVCT...WILL HOLD OFF AS CONFIDENCE NOT HIGH.
&&
.MARINE...DECIDED TO GO WITH SCA FOR NORTHERN BAYS AS WINDS AOA 20
KNOTS ESPECIALLY AT PORT OCONNOR AND PALACIOS. WINDS EXPECTED TO
DIMINISH LATE...BUT WILL WATCH AS RUC13 STILL HAD WINDS UP IN THAT
AREA.
&&
.PREV DISCUSSION... /ISSUED 625 AM CDT SAT APR 21 2012/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD. GUSTY
WINDS WILL DEVELOP THIS AFTERNOON...BUT THEN DECREASE TO LIGHT
LEVELS ONCE AGAIN TONIGHT.
PREV DISCUSSION... /ISSUED 408 AM CDT SAT APR 21 2012/
SHORT TERM (TODAY THROUGH SUNDAY)...HIGH PRESSURE BUILDING IN WILL KEEP
A GENERALLY QUIET SHORT TERM FORECAST PERIOD. SHOULD BE A RATHER
PLEASANT DAY ACROSS THE AREA...BUT WITH A BIT OF A NORTHEAST
BREEZE...MORE SO ALONG THE BAYS AND OFFSHORE. TEMPERATURES WILL BE
A FEW DEGREES COOLER THAN RECENT DAYS...BUT STILL INTO THE 80S FOR
MOST OF THE AREA. DRIER AIR AND LIGHT WINDS SHOULD ALLOW TEMPS
TONIGHT TO COOL INTO THE 50S FOR MOST OF THE AREA. TEMPERATURES
WARM A FEW DEGREES MORE FOR SUNDAY.
LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)...THE EXTENDED PART OF
THE FORECAST WILL BEGIN WITH UPPER LEVEL RIDGE OVER THE ROCKIES.
THIS WILL MAINTAIN A DRY NORTH NORTHWEST FLOW ACROSS SOUTH TEXAS...
WITH QUIET WEATHER INTO NEXT WEEK. AT THE SURFACE...HIGH PRESSURE
WILL BE BUILDING SOUTHWARD INTO SOUTH TEXAS. LIGHT WINDS AND CLEAR
SKIES SUNDAY NIGHT WILL LEAD TO A COOLER NIGHT WITH TEMPS IN THE MID
AND UPPER 50S IN MOST LOCATIONS. SURFACE HIGH WILL MOVE INTO THE
GULF BY TUESDAY...WHICH WILL BRING A RETURN TO ONSHORE FLOW. A
GRADUAL WARMING TREND WILL OCCUR THROUGH THE WEEK WITH ABOVE NORMAL
NORMAL TEMPERATURES BY TUESDAY/WEDNESDAY. PROSPECTS FOR SHOWERS AND
STORMS WILL BE LOW FOR THE UPCOMING WEEK AS UPPER RIDGING WILL BE
THE DOMINANT WEATHER FEATURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 79 56 83 60 83 / 0 0 0 0 0
VICTORIA 76 51 81 56 81 / 0 0 0 0 0
LAREDO 85 58 90 64 90 / 0 0 0 0 0
ALICE 81 53 86 57 86 / 0 0 0 0 0
ROCKPORT 76 58 79 62 79 / 0 0 0 0 0
COTULLA 82 53 87 57 87 / 0 0 0 0 0
KINGSVILLE 81 54 85 59 85 / 0 0 0 0 0
NAVY CORPUS 77 62 79 64 80 / 0 0 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM PORT ARANSAS TO
PORT O`CONNOR.
&&
$$
GW/86...SHORT TERM/AVIATION
TT/89...LONG TERM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
250 PM CDT SAT APR 21 2012
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING SOUTHEAST OVER THE RED RIVER VALLEY EARLY THIS AFTERNOON...AS
A STRONG SHORTWAVE WITHIN THE LEFT EXIT REGION OF A JET STREAK DIVES
OVER THE NORTHERN MISSISSIPPI VALLEY. ALONG THE 850MB WARM
FRONT...A BAND OF RAIN IS CROSSING THE MINNESOTA/WISCONSIN STATE
BORDER WHILE A MID-LEVEL CLOUD DECK IS MOVING INTO CENTRAL AND
NORTH-CENTRAL WISCONSIN. DRY EAST FLOW OVER THE EASTERN HALF OF THE
STATE HAS BEEN DELAYING THE PROGRESS OF THESE CLOUDS UP UNTIL NOW.
AS THE SURFACE LOW TRACKS SOUTHEAST...SMALL PRECIP CHANCES AND CLOUD
TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...DECENT SHORTWAVE TROUGH WILL DIVE SE WITHIN THE LEFT EXIT
REGION OF A JET STREAK AND DRIVE A SURFACE LOW OVER THE NORTHERN AND
CENTRAL MISSISSIPPI RIVER VALLEY. THE 850MB THETAE GRADIENT WILL
REMAIN WELL WEST OF THE REGION FOR ANY PRECIP THREAT...BUT WILL SEE
MID AND HIGH CLOUDS ON THE INCREASE FOR THE REST OF THIS AFTERNOON
INTO THIS EVENING. DURING THE OVERNIGHT PERIOD...NE WINDS WILL
ADVECT DRY AIR OUT OF A HUDSON BAY HIGH ACROSS NORTHEAST AND INTO
CENTRAL WISCONSIN...WHERE SHOULD SEE PARTIAL CLEARING AS THE
MID-DECK IS ERODED. IN THE END THOUGH...WILL GO WITH PARTLY TO
MOSTLY CLOUDY SKIES WITH LOWS RANGING FROM THE UPPER 20S NORTH TO
MID 30S SOUTH.
SUNDAY...BEHIND THE DEPARTING SURFACE LOW...A SURFACE TROUGH WILL
HANG BACK ACROSS THE NORTHERN MISSISSIPPI VALLEY. NE WINDS EAST OF
THE SURFACE TROUGH WILL CONTINUE TO FUNNEL IN DRY AIR OVER NORTHEAST
AND CENTRAL WISCONSIN FOR MUCH OF THE MORNING. BUT DURING THE
AFTERNOON...NW WINDS ALOFT WILL START TO PUSH RESIDUAL MOISTURE
ALONG THE TROUGH INTO CENTRAL AND N-C WISCONSIN. SATURATION BECOMES
200-300MB DEEP IN THE AFTERNOON OVER THIS REGION...BUT PROGGED
SOUNDINGS DO NOT SHOW ANY MID-LEVEL INSTABILITY. IN
ADDITION...CANNOT FIND A TRIGGER AND IT ACTUALLY LOOKS LIKE
SHORTWAVE RIDGING TRIES TO BUILD OVER NORTHERN WISCONSIN IN THE
AFTERNOON. AS A RESULT...WILL STICK WITH A DRY FORECAST DESPITE THE
WIDESPREAD SHOWER ACTIVITY UPSTREAM. HIGH TEMPS WILL BE SIMILAR TO
TODAY...MAYBE A DEGREE OR TWO WARMER OVER NE WISCONSIN.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...TRYING TO SORT OUT
MODEL DIFFERENCES WITH MINOR PCPN CHANCES IS THE MAIN FCST CHALLENGE.
A HIGH AMPLITUDE RIDGE OVER THE ROCKIES AND UPPER LOW OVER THE
EASTERN GREAT LAKES AND NE U.S. WILL DOMINATE THE WEATHER PATTERN FOR
THE BEGINNING OF THE PERIOD. WISCONSIN WILL BE BETWEEN THESE TWO
FEATURES...WITH N-NW FLOW ALOFT. THE PATTERN IS EXPECTED TO
DEAMPLIFY BRIEFLY BY THE MIDDLE OF NEXT WEEK...THEN AMPLIFY AGAIN
LATE IN THE WORK WEEK WITH A STG UPPER RIDGE MOVG INTO THE
NORTHERN PLAINS.
HAVE IGNORED THE SPOTTY QPF SHOWN BY THE MODELS OVER NC WI ON SUNDAY
EVG...AS THERE DOESN`T APPEAR TO BE ANY REAL TRIGGER TO LATCH ONTO.
MODEL TIMESECTIONS DO SHOW QUITE A BIT OF MOISTURE IN THE 850-700 MB
RANGE...SO MOSTLY CLOUDY SKIES LOOK LIKE A GOOD BET. DRY CONDITIONS
WITH PARTLY TO MOSTLY CLOUDY SKIES SHOULD PREVAIL THROUGH MONDAY NIGHT.
ON TUESDAY...HAVE BACKED OFF A BIT ON PCPN CHCS FROM THE PREVIOUS FCST...
BUT DID KEEP A SLIGHT CHC OVER THE SW HALF OF THE CWA. MODELS SHOW
LOW PRESSURE DROPPING SE OUT OF THE NORTHERN PLAINS...WITH A STG
BAROCLINIC ZONE AND SOME INSTABILITY SETTING UP JUST TO OUR SOUTHWEST.
WEAK SFC RIDGING WILL STILL BE IN PLACE OVER NE WI...ALONG WITH VERY
DRY AIR AT 850 MB...SO PULLED POPS THERE ON TUESDAY. CONTINUED
LOW-END POPS ON TUESDAY NIGHT AND WEDNESDAY...AS THE PATTERN DOESN`T
CHANGE MUCH. IF THE RIDGING OVER NE WI ENDS UP BEING A LITTLE
STRONGER...THIS COULD TURN INTO A DRY FCST. EXPECT SEASONABLE
TEMPERATURES DURING THIS PERIOD.
CANADIAN HIGH PRESSURE IS EXPECTED TO DOMINATE ON THU/FRI...WITH DRY
CONDITIONS AND TEMPS A LITTLE BLO NORMAL.
MODEL BLEND GIVES US A CHANCE OF SHOWERS ON FRIDAY NIGHT/SATURDAY...
BUT THE LATEST RUN OF THE ECMWF SEEMS TO BACK OFF ON THIS...AND
CHANGES MAY BE NEEDED WITH SUBSEQUENT FCSTS. CONFIDENCE IS VERY LOW
FOR THIS PORTION OF THE FCST.
&&
.AVIATION...A WEAK LOW PRESSURE SYSTEM WILL DROP SOUTHEAST ALONG THE
MISSISSIPPI RIVER VALLEY. DRY EAST FLOW WILL KEEP THE SHOWERS FROM
THE SYSTEM WEST OF THE TAF SITES...BUT WILL SEE SCT-BKN 5-6KFT
CLOUDS MOVE INTO CENTRAL AND NORTH-CENTRAL WISCONSIN THIS AFTERNOON
THROUGH MUCH OF TOMORROW. WILL HAVE A FAIRLY DEEP SATURATED LAYER
OVER N-C WISCONSIN TOMORROW AFTERNOON AND MAY SEE A SPRINKLE OUT OF
IT...BUT CHANCES TOO LOW AT THE MOMENT TO INCLUDE IN THE TAFS.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
104 PM CDT SAT APR 21 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
342 AM CDT SAT APR 21 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES TODAY THROUGH
SUNDAY.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ACROSS MUCH OF THE WESTERN U.S....TROUGHING
ENCOMPASSING MUCH OF THE WESTERN GREAT LAKES REGION...AND AN UPPER
LOW NEAR THE SOUTHWEST LOUISIANA COAST. COMING INTO THE UPPER
TROUGHING WAS A SHORTWAVE OVER NORTHERN NORTH DAKOTA. A LARGE AMOUNT
OF MID AND HIGH CLOUDS WERE PRESENT AHEAD OF THE SHORTWAVE...
STREAMING INTO THE WESTERN PART OF THE FORECAST AREA. RADAR AND
SURFACE OBS SHOW SHOWERS OCCURRING ACROSS EASTERN NORTH DAKOTA...IN
AN AREA OF DPVA AHEAD OF THE SHORTWAVE...WARM ADVECTION NOTED BY
SOUTHWEST WINDS OF 20-25 KT AT 850MB ON ABR AND FGF RADARS...AND
UPPER DIVERGENCE IN THE LEFT EXIT REGION OF A 100 KT JET STREAK OVER
SOUTH DAKOTA. RUC CROSS-SECTIONS SHOW A NICE LOW TO MID-LEVEL
FRONTOGENESIS ZONE THERE TOO WITH A FRONTOLYSIS/FRONTOGENESIS
COUPLET. PRECIPITABLE WATER UP IN EASTERN NORTH DAKOTA AROUND 0.5
INCH PER 00Z SOUNDINGS FROM BIS AND ABR. CLOSER TO THE FORECAST
AREA...A SURFACE HIGH PRESSURE RIDGE IS IN PLACE. MAINLY CLEAR SKIES
UNTIL RECENTLY COMBINED WITH DRY AIR NOTED BY PRECIPITABLE WATER OF
0.24 INCHES ON THE 00Z GRB SOUNDING HAS ALLOWED TEMPERATURES TO DROP
INTO MOSTLY THE 30S...COLDEST OVER CENTRAL WISCONSIN WHERE A FEW
UPPER 20S HAVE OCCURRED.
REGARDING CURRENT FROST/FREEZE HEADLINES...HAVE DROPPED THE FROST
ADVISORY AS CLOUDS SEEM TO BE HAMPERING TEMPS FROM DROPPING ENOUGH
TO PRODUCE WIDESPREAD FROST. CONSIDERED DROPPING FREEZE WARNING TOO
GIVEN CURRENT READINGS...BUT WITH ONLY THE TYPICAL COLD SPOTS IN
CENTRAL WISCONSIN BELOW FREEZING...WILL LET IT CONTINUE FOR NOW.
TODAY AND TONIGHT...FOCUS IS ON THE SHORTWAVE OVER NORTH DAKOTA.
GOOD MODEL AGREEMENT EXISTS OF THE SHORTWAVE TRACKING SOUTHEAST INTO
WESTERN IOWA BY THIS EVENING AND INTO SOUTHERN ILLINOIS LATE
TONIGHT. LOW PRESSURE AREA ACCOMPANYING THE SHORTWAVE TAKES PRETTY
MUCH THE SAME TRACK...WITH AN INVERTED TROUGH LINGERING BACK INTO
SOUTHWEST MINNESOTA AT THE SURFACE AFTER IT PASSES. ALTHOUGH THE
SHORTWAVE AND SURFACE FEATURES ARE TRACKING WEST OF HERE...WE STILL
SEE 30-40 METER 500MB HEIGHT FALLS TODAY...UPPER DIVERGENCE IN THE
LEFT EXIT REGION OF THAT 100 KT JET THIS AFTERNOON...AND THAT
FRONTOGENESIS/FRONTOLYSIS COUPLET IN THE LOW TO MID LEVELS MOVE
THROUGH WESTERN SECTIONS OF THE FORECAST AREA THIS AFTERNOON AND
EVENING. WITH A SURGE OF PRECIPITABLE WATER ACCOMPANYING THE
SYSTEM...UP TO 0.5 INCH OR SO...PRECIPITATION SEEMS TO BE A PRETTY
GOOD BET. HAVE RAISED CHANCES UP TO 100 FOR LOCATIONS MAINLY WEST OF
THE MISSISSIPPI RIVER FOR THIS AFTERNOON AND EVENING. FOR LOCATIONS
NORTH AND EAST OF I-94...THEY ARE ON THE WRONG / SUBSIDENT SIDE OF
THE FRONTOGENETICAL CIRCULATION. THEREFORE...DRY CONDITIONS ARE
MOSTLY EXPECTED THERE. TOTAL QPF AMOUNTS COULD BE UPWARDS OF 0.30
INCHES...A FAR CRY FROM THURSDAY. LOOK FOR PRECIPITATION TO DIMINISH
AFTER MIDNIGHT AS FORCING WEAKENS AND/OR SHIFTS SOUTHEAST OF HERE.
WITH A LOT OF CLOUDS TODAY AND EVENTUALLY RAIN COMING IN THIS
AFTERNOON FOR SOME AREAS...AS WELL AS 850MB TEMPS OF 0 TO -2C...
EXPECTING COOLER TEMPERATURES TODAY. STAYED ON THE COOL SIDE OF
GUIDANCE OUT WEST THEN A BLEND ELSEWHERE. MAY SEE A LITTLE DROP IN
TEMPS IN THE AFTERNOON WHERE IT RAINS DUE TO EVAPORATIVE COOLING. A
BLEND OF GUIDANCE SEEMS REASONABLE FOR LOWS TONIGHT BEING UNDER
PERSISTENT CLOUDS.
SUNDAY AND SUNDAY NIGHT...500MB HEIGHTS PROGGED TO RISE OVER THE
FORECAST AREA DURING MUCH OF THIS PERIOD IN THE WAKE OF
TODAY/TONIGHTS SHORTWAVE...THOUGH SOLIDLY REMAINING IN NORTHWEST
FLOW ALOFT. AS THE HEIGHTS RISE...THE INVERTED TROUGH OVER SOUTHWEST
MINNESOTA WEAKENS AND PUSHES EAST TOWARDS THE MISSISSIPPI RIVER BY
00Z. LOW LEVEL CONVERGENCE ON THIS TROUGH IN CONJUNCTION WITH
DAYTIME HEATING COULD BE ENOUGH TO PRODUCE A FEW SHOWERS...THOUGH
CONFIDENCE IS PRETTY LOW GIVEN THAT CLOUD COVER MAY PERSIST THROUGH
MUCH OF THE DAY. PLUS...AN EASTERLY FLOW IS PROGGED TO DEVELOP OVER
WISCONSIN AHEAD OF HIGH PRESSURE DROPPING DOWN INTO LAKE SUPERIOR.
THIS EASTERLY FLOW WILL DRIVE DRY AIR INTO THE AREA. MOST MODELS
ARE EITHER DRY OR CLOSE TO IT WITH QPF FIELDS. THEREFORE...HAVE
REDUCED PRECIPITATION CHANCES BY 10 PERCENT AND SHIFTED THE MAX AREA
WESTWARD CLOSER TO THE INVERTED TROUGH. ANY PRECIP WILL END BY 00Z
MONDAY AS THE SURFACE RIDGE BUILDS INTO THE AREA. TEMPERATURES ARE A
LITTLE TRICKY FOR SUNDAY NIGHT AS MODELS NOW SUGGEST SOME CLOUDS
UP AROUND THE DULUTH AREA DROPPING SOUTH WITH THE SURFACE RIDGE. AS
SUCH...FOR NOW LEANED A LITTLE CLOSER TO A MODEL CONSENSUS...SAME
TOO FOR HIGHS ON SUNDAY. CERTAINLY IF WE CLEAR OUT MORE THAN
EXPECTED...FROST/FREEZE CONDITIONS MAY BECOME A WORRY FOR SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT...THE FORECAST AREA IS EXPECTED TO BE STUCK
BETWEEN STRONG RIDGING IN THE WESTERN U.S. AND DEEP TROUGHING OVER
THE EASTERN U.S.. THE POSITION FAVORS HIGH PRESSURE AT THE
SURFACE...WHICH HOLDS TRUE FOR THE DAY MONDAY. THERE ARE SUGGESTIONS
OF A SLIGHT EASTWARD PUSH OF THE UPPER RIDGE MONDAY NIGHT...WHICH IN
TURN CAUSES A WARM ADVECTION SURGE INTO THE FORECAST AREA. 850MB
TEMPS CLIMB FROM 2-4C AT 00Z TUESDAY TO 6-10C AT 12Z TUESDAY. THE
21.00Z GFS/NAM DEVELOP QPF WITH THIS SURGE OF WARM ADVECTION OVER
NORTHERN AND EASTERN WISCONSIN...POSSIBLY CLIPPING TAYLOR AND ADAMS
COUNTIES. FOR NOW HAVE DECIDED TO KEEP IT DRY IN AGREEMENT WITH THE
ECMWF AND PREVIOUS FORECASTS...THINKING TOO THAT THERE IS NOT MUCH
MOISTURE TO WORK WITH AFTER BEING UNDER THE SURFACE HIGH PRESSURE
RIDGE. SOMETHING TO WATCH...THOUGH. WITH MAINLY SUNNY SKIES ON
MONDAY AND THE WARMING 850MB TEMPS...DEEP MIXING SHOULD OCCUR WITH
HIGHS TOPPING OUT IN THE UPPER 50S/LOW 60S. INCREASING SOUTHWEST
FLOW AHEAD OF A SURFACE TROUGH DROPPING DOWN INTO NORTHERN WISCONSIN
MONDAY NIGHT AND THE WARMER 850MB TEMPS COMING IN SHOULD HELP TO
PRODUCE A WARMER NIGHT.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
342 AM CDT SAT APR 21 2012
BETTER AGREEMENT EXISTS WITH THE 21.00Z ECMWF/GFS/CANADIAN AND GFS
ENSEMBLES TODAY THAN SEEN YESTERDAY. THE WESTERN RIDGE AND EASTERN
TROUGH PATTERN SEEN RECENTLY LOOKS TO CONTINUE THROUGH MUCH OF THE
LONG TERM FORECAST...THOUGH TOWARDS FRIDAY SOME FAIRLY DEEP
TROUGHING DEVELOPS ALONG THE WEST COAST OF THE U.S. TO HELP PUSH
THAT WESTERN RIDGE EASTWARD. WE GET A BRIEF TASTE OF THE WARM AIR
OUT OF THE UPPER RIDGE TUESDAY AND TUESDAY NIGHT...AHEAD OF A LOW
PRESSURE AREA DEEPENING OVER THE DAKOTAS AND SLIDING DOWN INTO IOWA.
WARM ADVECTION AHEAD OF THIS LOW SHOULD PRODUCE SOME SHOWERS AND
POSSIBLY THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY. LOCATIONS WEST
OF THE MISSISSIPPI RIVER SEEM MOST FAVORABLE RIGHT NOW FOR
PRECIPITATION. HIGH PRESSURE THEN DROPS IN FROM CANADA FOR WEDNESDAY
NIGHT THROUGH FRIDAY NIGHT...WITH MAYBE A BRIEF DRY COLD FRONT
MOVING THROUGH BETWEEN THEN ON THURSDAY NIGHT. THEREFORE...WHEN IT
COMES TO TEMPERATURES...WARMEST READINGS ARE EXPECTED ON TUESDAY AND
WEDNESDAY. MAY HAVE TO DEAL WITH FROST/FREEZE CONDITIONS THURSDAY
NIGHT OR FRIDAY NIGHT OVER CENTRAL WISCONSIN. SOMETHING TO WATCH.
&&
.AVIATION...THROUGH 18Z SUNDAY
104 PM CDT SAT APR 21 2012
AS OF 18Z SATURDAY...BAND OF MOSTLY VFR CEILINGS WITH SCATTERED
RAIN SHOWERS ALONG THE I-35 CORRIDOR IN MINNESOTA...MOVING SLOWLY
EASTWARD TOWARDS KRST/KLSE..ALL ASSOCIATED WITH SURFACE LOW IN
NORTHWEST MINNESOTA. EXPECT PRECIPITATION TO MAKE IT TO KRST BY MID
AFTERNOON...WHILE DRIER AIR IN THE LOW LEVELS ALONG AND EAST OF
THE MISSISSIPPI RIVER SHOULD KEEP BULK OF PRECIPITATION AWAY FROM
KLSE SO KEPT A SMALL WINDOW OF SHOWERS TONIGHT AND CONTINUED THE
VFR CONDITIONS.
THE SURFACE LOW SLIDES SOUTHEAST TONIGHT...BRINGING MVFR CEILINGS
AT KRST...IN THE 1500 TO 2000 FT RANGE. THERE IS A CHANCE FOR A
PERIOD OF IFR CEILINGS...BUT CONFIDENCE IS LOW FOR AN EXTENDED
PERIOD...AS DRIER AIR BUILDS SLIGHTLY WEST AND WILL TRY TO
COUNTERACT ANY CEILING LOWERING. SOMETHING TO MONITOR THIS
AFTERNOON/EVENING.
FOR SUNDAY...HIGH PRESSURE BUILDS IN AND CEILINGS WILL LIFT TO
VFR AT KRST. LATEST MODEL RH FIELDS SUGGEST BAND OF LOW CLOUDS POSSIBLE
TO THE WEST ACROSS SOUTHWEST MINNESOTA ASSOCIATED WITH THE
DEPARTING LOW...BUT FOR NOW FEEL THE DRY AIR PUSH SHOULD KEEP
THESE CLOUDS TO THE WEST OF THE TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CDT SAT APR 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....ZT