Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/19/12
AREA FORECAST DISCUSSION
NWS DENVER CO
302 PM MDT TUE APR 17 2012
.SHORT TERM...WEAK SHORTWAVE FINALLY SLIDING ACROSS WYOMING WITH
TAIL END MOVING OVER NORTHWEST COLORADO. RADAR SHOWING SOME
PRECIPITATION DEVELOPING OVER THE NORTHERN MOUNTAINS THOUGH WEB
CAMS SHOWING MOST OF THIS ACTIVITY ALONG CONTINENTAL DIVIDE IN
GRAND COUNTY. SHOULD BEGIN TO SEE THE PRECIP BECOMING A BIT MORE
WIDESPREAD AS MID LEVEL QG ASCENT INCREASES. MODELS SHOW BEST LIFT
TO STAY WELL NORTH OF COLORADO AS WAVE MOVES ACROSS REGION. RUC
AND NAM CROSS SECTIONS SHOW SOME INCREASE IN MOISTURE...MAINLY
ABOVE MOUNTAIN TOP. LATEST RUC AND HRRR AS WELL AS THE 18Z NAM
RUN DO NOT GENERATE MUCH IN THE WAY OF QPF THROUGH THE EVENING.
WILL MAINTAIN THE SCATTERED POPS FOR MOST OF MOUNTAIN AREAS NORTH
OF INTERSTATE 70 THROUGH EARLY EVENING...WITH DECREASING POPS
REST OF THE EVENING. AS FOR THUNDER CHANCES...FORECAST CAPES STILL
LOOKING LOW...MAYBE 300 J/KG FOR A SHORT TIME OVER THE NORTHERN
MOUNTAINS. SO FAR...NO LIGHTNING NOTED UPSTREAM. WILL NOT INCLUDE
FOR EVENING FORECASTS. TEMPERATURES TO BE COLD ENOUGH FOR SNOW
ACROSS THE MOUNTAINS WITH MAINLY RAIN VALLEY AREAS. ACROSS
PLAINS...STILL A SLIGHT CHANCE FOR A FEW HIGH BASED SHOWERS ALONG
THE WYOMING BORDER EARLY THIS EVENING WITH REST OF THE PLAINS DRY.
WINDS TO INCREASE FOR A SHORT TIME BEHIND THE EXITING WAVE BEFORE
DECREASING DURING THE EVENING. GRADUAL CLEARING EXPECTED OVERNIGHT
WHICH SHOULD KEEP TEMPERATURES FAIRLY MILD. ON WEDNESDAY...NEXT
TROUGH APPROACHES FROM THE NORTHWEST AS MODERATE WESTERLY FLOW
ALOFT CONTINUES OVER COLORADO. MODEL CROSS SECTIONS SHOW SOME
INCREASE IN MOISTURE ACROSS MOUNTAINS DURING THE AFTERNOON ALONG
WITH SOME WEAK QG ASCENT. BEST AREA FOR ANY PRECIPITATION LOOKS TO
BE THE NORTHERN MOUNTAINS SO WILL WILL INCREASE THE POPS THERE TO
THE CHANCE CATEGORY FOR THE AFTERNOON. THICKNESS PROGS SUGGEST
A SLIGHT CHANCE OF SNOW. FORECAST CAPES REMAIN LOW SO WILL NOT
MENTION THUNDER. AS FOR PLAINS...SOME SHOWERS POSSIBLE FOR AREAS
NEAR THE WYOMING BORDER IN AREA OF BETTER ASCENT. MODELS GENERATE
SOME CAPE ALONG THE BORDER...STILL LOOK A BIT LOW TO MENTION
THUNDER AT THIS TIME. THE SHOWERS THAT DO DEVELOP SHOULD BE HIGH
BASED AND CAPABLE OF PRODUCING BRIEF GUSTY WINDS. WILL LEAVE REST
OF PLAINS DRY. SOUTHERLY WINDS TO INCREASE AHEAD OF TROUGH...
THOUGH MODELS SHOW WINDS MORE WESTERLY ACROSS PLAINS WITH PASSAGE
OF WEAK FRONT. THIS MAY BE A BIT FAST GIVEN TO SLOW MOVEMENT OF
UPPER TROUGH. TEMPERATURE AND THICKNESS PROGS AS WELL AS GUIDANCE
SHOW HIGHS IN THE LOWER AND MIDDLE 70S ACROSS PLAINS. CURRENT
TEMPERATURE GRIDS IN LINE WITH GUIDANCE...LOOKS REASONABLE.
.LONG TERM...THE NEXT UPPER LEVEL TROF WILL MOVE ACROSS COLORADO
ON LATE WEDNESDAY AND THURSDAY AND GRADUALLY DEEPEN AS IT MOVES
INTO THE CENTRAL PLAINS. THE MODELS ARE VARIED ON MOISTURE
AVAILABILITY WITH THE GFS THE WETTER OF THE MODELS AND MORE
UPSLOPE WHILE THE NAM LOOKS LIKE DRIER WITH THE MOST DOWNSLOPE
FLOW. GIVEN THE VARIABILITY WILL LEAVE THE POPS MAINLY IN THE
SLIGHT CHANCE OVER LOWER ELEVATIONS BUT A SLIGHT BUMP UPWARDS. THE
MOUNTAINS WILL PROBABLY HAVE A BRIEF PERIOD OF RAIN/SNOW SHOWERS
ON THURSDAY AND THROUGH THE NIGHT WITH LIGHT NW OROGRAPHIC FLOW.
THE QG FIELDS ARE ONLY SHOWING WEAK ASCENT SO AT THIS POINT NOT
ALL THAT EXCITED ABOUT THIS NEXT DISTURBANCE.
HIGH PRESSURE RIDGE ALOFT WILL BUILD OVER THE ENTIRE REGION FROM
FRIDAY THROUGH EARLY NEXT WEEK WITH DRYING AND WARMING TREND
THROUGH THE PERIOD. MODELS ARE SHOWING A BIT OF MOISTURE
DEVELOPING UNDER THE RIDGE BY EARLY NEXT WEEK BUT NOT WORTH ADDING
ANY POPS AT THIS TIME.
&&
.AVIATION...TROUGH STILL WEST OF THE DENVER AREA...WITH VARIABLE
WINDS AT AREA AIRPORTS. THROUGH EXPECTED TO MOVE ACROSS THE AREA
EARLY EVENING. SHOULD SEE WINDS SHIFT TO THE NORTHWEST BY 23Z WITH
SPEEDS AROUND 15 KTS. SOME INCREASE IN MID LEVEL CLOUDS BUT NOW
DOES NOT APPEAR THAT ILS CEILINGS WILL DEVELOP. WILL MAINTAIN THE
LATEST UPDATE TRENDS FOR THE 00Z ISSUANCE. ANY SHOWERS THAT
DEVELOP WILL STAY NORTH AND WEST OF DENVER AIRPORTS. WINDS TO
DECREASE AND BECOME SOUTHERLY DURING THE EVENING AS DRAINAGE FLOW
DEVELOPS. THE SOUTHERLY WINDS TO CONTINUE THROUGH THE DAY...MAY
BECOME A BIT MORE SOUTHEAST DURING THE AFTERNOON. SOME HIGH BASED
SHOWERS POSSIBLE NORTH OF THE AREA AFTER 18Z...NOT EXPECTED TO
AFFECT THE AREA AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
403 PM EDT TUE APR 17 2012
.SYNOPSIS...
A COLD FRONT WILL REMAIN POSITIONED WEST OF THE REGION OVERNIGHT.
THE FRONT WILL MOVE SLOWLY ACROSS THE REGION WEDNESDAY AFTERNOON AND
WEDNESDAY NIGHT BEFORE STALLING OVER OR JUST EAST OF THE AREA INTO
FRIDAY. A STRONG LOW PRESSURE SYSTEM WILL THEN AFFECT THE REGION
THIS WEEKEND FOLLOWED BY COOLER HIGH PRESSURE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THIS AFTERNOON...THE EXPANSIVE CU FIELD CONTINUES ACROSS THE
FORECAST AREA WITH THE SEA BREEZE BEGINNING TO PUSH INLAND. SO FAR
THE SUBSIDENCE INVERSION AND CAP NOTICED ON MODEL SOUNDINGS IS
HOLDING AND NO SHOWERS OR STORMS HAVE STARTED DEVELOPING ACROSS THE
REGION. WATER VAPOR IMAGERY AND RUC DATA SHOW THE OFFSHORE RIDGE
HOLDING STRONG...AND RECENT RUNS OF THE HRRR SHOW VIRTUALLY NO
COVERAGE THROUGH THE EVENING HOURS.
TONIGHT...THE UPSTREAM SHORTWAVE WILL BEGIN TO MAKE SOME EASTWARD
PROGRESS AND GRADUALLY ERODE THE UPPER RIDGE. THROUGH SUNRISE IT
LOOKS AS THOUGH THE MAIN VORT ENERGY WILL REMAIN JUST WEST OF THE
FORECAST AREA. THE COLD FRONT WILL MAKE LITTLE PROGRESS OVERNIGHT AS
A WEAK SURFACE WAVE DEVELOPS OVER SOUTH AL/GA AND BEGINS TO RIDE TO
THE NE. THIS WILL PLACE THE FORECAST AREA IN BETWEEN THE WEAK
SURFACE LOW AND THE WESTERN ATLANTIC HIGH...WHICH WILL SUPPORT LIGHT
BUT PERSISTENT S TO SW FLOW. OVERALL SKIES WILL BE CLEAR TO MOSTLY
CLEAR FOR MUCH OF THE NIGHT...WITH SOME MAINLY HIGH LEVEL CLOUDINESS
MOVING IN FROM THE WEST. THERE ARE SOME INDICATIONS THAT AREAS OF
STRATOCU COULD DEVELOP AND ADVECT INLAND OVERNIGHT...BUT MODELS
DON/T SHOW A TREMENDOUS AMOUNT OF MOISTURE IN THE LOWEST 5K FT OF
THE ATMOSPHERE. THERE MAY ALSO BE SOME SHALLOW GROUND FOG IN THE FEW
HOURS RIGHT AROUND SUNRISE...BUT WE SHOULD MAINTAIN ENOUGH FLOW TO
PREVENT FOG FROM MUCH DEEPER OR WIDESPREAD. I HAVE TAPERED POPS BACK
TO KEEP MOST OF THE OVERNIGHT DRY...WITH JUST A SMALL AREA OF SLIGHT
CHANCE TO CHANCE ACROSS THE WEST AROUND SUNRISE. LOW TEMPS SHOULD BE
PRETTY SIMILAR TO LAST NIGHT...WITH LOW 60S TO NEAR 60 JUST ABOUT
EVERYWHERE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
AN UPPER SHORTWAVE TROUGH OF LOW PRESSURE WILL SHIFT THROUGH THE
AREA WEDNESDAY INTO WEDNESDAY NIGHT ALONG WITH A SURFACE COLD
FRONT AND WEAK AREA OF LOW PRESSURE. THE FRONT WILL THEN LIKELY
STALL OUT JUST OFFSHORE INTO FRIDAY AS HIGH PRESSURE SLIDES BY TO
THE NORTH. RAIN CHANCES LOOK TO INCREASE FROM THE WEST WEDNESDAY
THROUGH WEDNESDAY NIGHT WITH DEEPER MOISTURE MOVING THROUGH ALONG
WITH THE UPPER TROUGH AND SURFACE LOW/FRONT. INSTABILITY APPEARS
TO BE LIMITED ALTHOUGH 30-35 KT BULK SHEAR COULD LEAD TO A FEW
STRONGER STORMS. SOME SHOWERS AND THUNDERSTORMS EXPECTED THURSDAY
WITH THE LINGERING SURFACE BOUNDARY NEARBY...THE AFTERNOON SEA
BREEZE AND ADDITIONAL WEAK SHORTWAVE ENERGY ALOFT. RAIN CHANCES
LIKELY EVEN A BIT LESS ON FRIDAY GIVEN A BIT LESS MOISTURE AND
SLIGHT WARMING ALOFT. TEMPERATURES GENERALLY AT OR SLIGHTLY ABOVE
NORMAL...ESPECIALLY LOWS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A LARGE AND POTENTIALLY STRONG LOW PRESSURE SYSTEM WILL AFFECT THE
SOUTHEAST THIS WEEKEND. AT THIS TIME...MODELS ARE STRUGGLING WITH
THE TIMING AND TRACK OF THE LOW PRESSURE SYSTEM AS IT PASSES OVER
THE SOUTHEAST. LATEST GUIDANCE DOES FAVOR A MORE SOUTHERN TRACK OF A
DEEP LOW THROUGH THE SOUTHERN GULF STATES BEFORE SHIFTING OFF THE
SOUTHEAST ATLANTIC COAST. THIS TRACK ALONG WITH STRONG MID/UPPER LVL
DYNAMICS AND MODEST INSTABILITY IN THE WARM SECTOR WOULD FAVOR
STRONG THUNDERSTORMS OVER OR NEAR THE FORECAST AREA SOMETIME LATE
SATURDAY THROUGH SUNDAY EVENING. A COOLING/DRYING TREND IS THEN
ANTICIPATED ONCE FROPA OCCURS OVER THE WEEKEND. TEMPS WILL RANGE
FROM THE UPPER 70S/LOWER 80S SATURDAY AND POSSIBLY SUNDAY BEFORE
RETURNING TO NEAR OR BELOW NORMAL LEVELS MONDAY AND TUESDAY.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE TAF PERIOD. NO
CONCERNS IN THE FIRST 12 HOURS OF THE FORECAST...AFTER WHICH THERE
IS A SMALL CHANCE OF STRATOCU ADVECTING INLAND LATE TONIGHT. NONE
OF THE MODEL GUIDANCE IS HITTING THIS POTENTIAL VERY HARD SO I
HAVE LEFT THINGS VFR AND HAVE ONLY GONE WITH FEW MVFR CLOUDS. AS
THE WEAK SURFACE LOW DEVELOPS TO THE WEST...THE AREA WILL BE
CAUGHT BETWEEN THIS FEATURE AND THE PERSISTENT HIGH OVER THE
ATLANTIC. THIS SHOULD GENERATE ENOUGH FLOW TO KEEP FOG DEVELOPMENT
AS GROUND FOG AT BEST DESPITE CLEAR TO PARTLY CLOUDY SKIES. CLOUDS WILL
BEGIN INCREASING WEDNESDAY MORNING BUT IT APPEARS ANY PRECIP WILL
BE CONFINED TO THE AFTERNOON/EVENING HOURS.
EXTENDED AVIATION OUTLOOK...MVFR/IFR CIGS/VSBYS LIKELY AT BOTH
TERMINALS WED NIGHT AS SHOWERS/TSTMS AFFECT THE AREA AS A WEAK COLD
FRONT PUSHES OFFSHORE. ADDITIONAL MVFR/POSSIBLY WORSE CIGS/VSBYS
LATE THU NIGHT. BREEZY/GUSTY CONDITIONS LIKELY SAT WITH INCREASING
CHANCES FOR SUB-VFR CONDS THROUGH THE WEEKEND AS A STRONG LOW
PRESSURE SYSTEM APPROACHES THE AREA FROM THE W.
&&
.MARINE...
TONIGHT...THE LOCAL WATERS WILL BE CAUGHT IN AN AREA BETWEEN A
DEVELOPING WEAK LOW PRESSURE TO THE WEST AND HIGH PRESSURE JUST TO
THE EAST. THIS WILL HELP MAINTAIN A MODERATE S TO SW FLOW OF
GENERALLY 10 TO 15 KTS THROUGH THE NIGHT. SEAS WILL ALSO BE WELL
BELOW SCA CRITERIA...GENERALLY 2-3 FT WITH MOST OF THAT BEING
COMPRISED OF 1-2 FT SWELL EVERY 7-8 SECONDS.
WEDNESDAY THROUGH SUNDAY...A WEAK COLD FRONT WILL SHIFT OVER THE
COASTAL WATERS LATE WEDNESDAY INTO EARLY THURSDAY BEFORE STALLING
OUT OVER OR JUST E OF THE WATERS INTO FRIDAY. NO SIGNIFICANT MARINE
CONCERNS THROUGH FRI NIGHT...HOWEVER CONDITIONS WILL BEGIN TO GO
DOWNHILL LATER SATURDAY INTO SUNDAY AS A STRONG LOW PRESSURE SYSTEM
APPROACHES FROM THE WEST. SMALL CRAFT ADVISORIES ARE LIKELY SATURDAY
NIGHT FOR WINDS AND SEAS...AT LEAST BEYOND 20 NM...WITH THE
NEARSHORE WATERS LIKELY REACHING ADVISORY LEVELS SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BSH
SHORT TERM...RJB
LONG TERM...RJB
AVIATION...BSH/RJB
MARINE...BSH/RJB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1200 PM CDT TUE APR 17 2012
...UPDATE TO AVIATION FOR 18Z TAFS...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE APR 17 2012
MEDIUM RANGE MODELS INDICATE A ZONAL FLOW ALOFT PERSISTING ACROSS
THE WESTERN HIGH PLAINS TO BEGIN THE PERIOD WEDNESDAY. MEANWHILE, AN
UPPER LEVEL SHORTWAVE TROUGH WILL TRANSITION EAST FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES REGION. A FAIRLY WEAK ATTENDANT COLD
FRONT IS EXPECTED TO PUSH JUST INTO NORTHWESTERN KANSAS BEFORE
STALLING OUT, POSSIBLY JUST INTO NORTHERN PORTIONS OF SOUTHWEST
KANSAS AND PORTIONS OF CENTRAL KANSAS JUST SOUTH OF THE I-70
CORRIDOR. HOWEVER, NO SIGNIFICANT PRECIPITATION IS EXPECTED WITH
THIS FRONT WITH A GENERALLY WEAK FLOW ALOFT. HOWEVER, THE CHANCES
FOR PRECIP DO PICK UP A LITTLE THURSDAY AS ANOTHER UPPER LEVEL
SHORTWAVE IS PROGGED TO SWING ACROSS THE WESTERN PLAINS. AN
ATTENDANT COLD FRONT TO THIS SYSTEM WILL PUSH SOUTHEAST WELL INTO
AND ACROSS WESTERN KANSAS DURING THE DAY THURSDAY BRINGING THE
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS BY THURSDAY EVENING. HOWEVER, HOW STRONG ANY POSSIBLE STORMS
MAY BE REMAINS UNCERTAIN. NAM AND GFS MODEL SOUNDINGS HINT AT A
POSSIBLE LACK OF LOW LEVEL MOISTURE ALONG WITH LESS THAN FAVORABLE
INSTABILITY LEVELS. ADDITIONALLY, TIMING OF THE FRONT COULD BE AN
ISSUE AS WELL WITH ALL MODELS PROJECTING THE FRONTAL PASSAGE TO TAKE
PLACE EARLIER IN THE DAY. LOW END CHANCE CATEGORY POPS SEEM
REASONABLE AT THIS POINT. DRIER CONDITIONS ARE THEN EXPECTED
THROUGH THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK AS UPPER
LEVEL RIDGING DEVELOPS AND PUSHES EAST ACROSS THE INTERMOUNTAIN
WEST.
TEMPERATURES ARE EXPECTED TO BE JUST ABOVE NORMAL WEDNESDAY AS A
ZONAL FLOW PERSISTS ACROSS THE WESTERN HIGH PLAINS. A LEE SIDE
TROUGH OF LOW PRESSURE IS EXPECTED TO REDEVELOP ACROSS EASTERN
COLORADO RETURNING A LOW LEVEL SOUTHERLY FLOW TO SOUTHWESTERN AND
SOUTH CENTRAL KANSAS BY LATE AFTERNOON. THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES IN THE MID TO UPPER TEENS(C) ACROSS CENTRAL KANSAS
TO THE LOWER 20S(C) ACROSS SOUTHWESTERN KANSAS. WITH LOWER LEVEL DRY
LAPSE RATES LIKELY BY WEDNESDAY AFTERNOON, LOOK FOR HIGHS UP INTO
THE UPPER 70S(F) TO THE LOWER TO MID 80S(F). A GENERAL COOLING TREND
IS LIKELY THROUGH THE END OF THE WEEK AS MUCH COOLER AIR SURGES
SOUTH INTO WESTERN KANSAS IN WAKE OF THE COLD FRONTAL PASSAGE
THURSDAY. HIGHS COULD STRUGGLE TO REACH THE 70S(F) THURSDAY
DEPENDING ON ANY CLOUD COVER ASSOCIATED WITH THE COLD FRONT
AND THE TIMING OF THE PASSAGE ITSELF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1200 PM CDT TUE APR 17 2012
VFR CIGS EXPECTED THROUGH THE ENTIRE TAF PERIOD. SOME CIRRUS IS
POSSIBLE THROUGH THE PERIOD AS AN UPPER LEVEL SHORTWAVE TROUGH MOVES
THROUGH. NEXT CONCERN IS WIND SHIFTS...A WEAK COLD FRONT/FRAGMENTING
LEE SURFACE TROUGH AXIS WILL MOVE THROUGH DURING THE MORNING HOURS.
BREEZY 15-20 KT SW WINDS THIS AFTERNOON WILL GRADUALLY VEER BY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
612 AM CDT TUE APR 17 2012
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE APR 17 2012
MEDIUM RANGE MODELS INDICATE A ZONAL FLOW ALOFT PERSISTING ACROSS
THE WESTERN HIGH PLAINS TO BEGIN THE PERIOD WEDNESDAY. MEANWHILE, AN
UPPER LEVEL SHORTWAVE TROUGH WILL TRANSITION EAST FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES REGION. A FAIRLY WEAK ATTENDANT COLD
FRONT IS EXPECTED TO PUSH JUST INTO NORTHWESTERN KANSAS BEFORE
STALLING OUT, POSSIBLY JUST INTO NORTHERN PORTIONS OF SOUTHWEST
KANSAS AND PORTIONS OF CENTRAL KANSAS JUST SOUTH OF THE I-70
CORRIDOR. HOWEVER, NO SIGNIFICANT PRECIPITATION IS EXPECTED WITH
THIS FRONT WITH A GENERALLY WEAK FLOW ALOFT. HOWEVER, THE CHANCES
FOR PRECIP DO PICK UP A LITTLE THURSDAY AS ANOTHER UPPER LEVEL
SHORTWAVE IS PROGGED TO SWING ACROSS THE WESTERN PLAINS. AN
ATTENDANT COLD FRONT TO THIS SYSTEM WILL PUSH SOUTHEAST WELL INTO
AND ACROSS WESTERN KANSAS DURING THE DAY THURSDAY BRINGING THE
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS BY THURSDAY EVENING. HOWEVER, HOW STRONG ANY POSSIBLE STORMS
MAY BE REMAINS UNCERTAIN. NAM AND GFS MODEL SOUNDINGS HINT AT A
POSSIBLE LACK OF LOW LEVEL MOISTURE ALONG WITH LESS THAN FAVORABLE
INSTABILITY LEVELS. ADDITIONALLY, TIMING OF THE FRONT COULD BE AN
ISSUE AS WELL WITH ALL MODELS PROJECTING THE FRONTAL PASSAGE TO TAKE
PLACE EARLIER IN THE DAY. LOW END CHANCE CATEGORY POPS SEEM
REASONABLE AT THIS POINT. DRIER CONDITIONS ARE THEN EXPECTED
THROUGH THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK AS UPPER
LEVEL RIDGING DEVELOPS AND PUSHES EAST ACROSS THE INTERMOUNTAIN
WEST.
TEMPERATURES ARE EXPECTED TO BE JUST ABOVE NORMAL WEDNESDAY AS A
ZONAL FLOW PERSISTS ACROSS THE WESTERN HIGH PLAINS. A LEE SIDE
TROUGH OF LOW PRESSURE IS EXPECTED TO REDEVELOP ACROSS EASTERN
COLORADO RETURNING A LOW LEVEL SOUTHERLY FLOW TO SOUTHWESTERN AND
SOUTH CENTRAL KANSAS BY LATE AFTERNOON. THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES IN THE MID TO UPPER TEENS(C) ACROSS CENTRAL KANSAS
TO THE LOWER 20S(C) ACROSS SOUTHWESTERN KANSAS. WITH LOWER LEVEL DRY
LAPSE RATES LIKELY BY WEDNESDAY AFTERNOON, LOOK FOR HIGHS UP INTO
THE UPPER 70S(F) TO THE LOWER TO MID 80S(F). A GENERAL COOLING TREND
IS LIKELY THROUGH THE END OF THE WEEK AS MUCH COOLER AIR SURGES
SOUTH INTO WESTERN KANSAS IN WAKE OF THE COLD FRONTAL PASSAGE
THURSDAY. HIGHS COULD STRUGGLE TO REACH THE 70S(F) THURSDAY
DEPENDING ON ANY CLOUD COVER ASSOCIATED WITH THE COLD FRONT
AND THE TIMING OF THE PASSAGE ITSELF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 605 AM CDT TUE APR 17 2012
AREAS OF FOG HAVE DEVELOPED THIS MORNING ACROSS PORTIONS OF
SOUTHWEST KANSAS...INCLUDING IN THE VICINITY OF KGCK. PERIODS OF
IFR CIGS/VSBYS WILL CONTINUE IN THE VICINITY OF KGCK AND POSSIBLY
KDDC THROUGH MID MORNING. OTHERWISE, VFR CONDITIONS ARE EXPECTED
AT ALL TAF SITES FROM MID MORNING THROUGH LATE THIS EVENING. AS
FOR WINDS, A LEE SIDE TROUGH OF LOW PRESSURE WILL DEVELOP AND
STRENGTHEN ACROSS EASTERN COLORADO TODAY. AS A RESULT, LIGHT
SOUTHERLY WINDS EARLY THIS MORNING WILL INCREASE UP TO 15 TO
25KT BY EARLY THIS AFTERNOON. WINDS WILL THEN SUBSIDE THIS
EVENING BUT REMAIN SOUTHERLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
KSZ043-044-061>063-075>078-086>088.
&&
$$
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
400 AM CDT TUE APR 17 2012
...UPDATE TO LONG TERM...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE APR 17 2012
MEDIUM RANGE MODELS INDICATE A ZONAL FLOW ALOFT PERSISTING ACROSS
THE WESTERN HIGH PLAINS TO BEGIN THE PERIOD WEDNESDAY. MEANWHILE, AN
UPPER LEVEL SHORTWAVE TROUGH WILL TRANSITION EAST FROM THE NORTHERN
PLAINS INTO THE GREAT LAKES REGION. A FAIRLY WEAK ATTENDANT COLD
FRONT IS EXPECTED TO PUSH JUST INTO NORTHWESTERN KANSAS BEFORE
STALLING OUT, POSSIBLY JUST INTO NORTHERN PORTIONS OF SOUTHWEST
KANSAS AND PORTIONS OF CENTRAL KANSAS JUST SOUTH OF THE I-70
CORRIDOR. HOWEVER, NO SIGNIFICANT PRECIPITATION IS EXPECTED WITH
THIS FRONT WITH A GENERALLY WEAK FLOW ALOFT. HOWEVER, THE CHANCES
FOR PRECIP DO PICK UP A LITTLE THURSDAY AS ANOTHER UPPER LEVEL
SHORTWAVE IS PROGGED TO SWING ACROSS THE WESTERN PLAINS. AN
ATTENDANT COLD FRONT TO THIS SYSTEM WILL PUSH SOUTHEAST WELL INTO
AND ACROSS WESTERN KANSAS DURING THE DAY THURSDAY BRINGING THE
CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS BY THURSDAY EVENING. HOWEVER, HOW STRONG ANY POSSIBLE STORMS
MAY BE REMAINS UNCERTAIN. NAM AND GFS MODEL SOUNDINGS HINT AT A
POSSIBLE LACK OF LOW LEVEL MOISTURE ALONG WITH LESS THAN FAVORABLE
INSTABILITY LEVELS. ADDITIONALLY, TIMING OF THE FRONT COULD BE AN
ISSUE AS WELL WITH ALL MODELS PROJECTING THE FRONTAL PASSAGE TO TAKE
PLACE EARLIER IN THE DAY. LOW END CHANCE CATEGORY POPS SEEM
REASONABLE AT THIS POINT. DRIER CONDITIONS ARE THEN EXPECTED
THROUGH THE WEEKEND AND INTO THE EARLY PART OF NEXT WEEK AS UPPER
LEVEL RIDGING DEVELOPS AND PUSHES EAST ACROSS THE INTERMOUNTAIN
WEST.
TEMPERATURES ARE EXPECTED TO BE JUST ABOVE NORMAL WEDNESDAY AS A
ZONAL FLOW PERSISTS ACROSS THE WESTERN HIGH PLAINS. A LEE SIDE
TROUGH OF LOW PRESSURE IS EXPECTED TO REDEVELOP ACROSS EASTERN
COLORADO RETURNING A LOW LEVEL SOUTHERLY FLOW TO SOUTHWESTERN AND
SOUTH CENTRAL KANSAS BY LATE AFTERNOON. THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES IN THE MID TO UPPER TEENS(C) ACROSS CENTRAL KANSAS
TO THE LOWER 20S(C) ACROSS SOUTHWESTERN KANSAS. WITH LOWER LEVEL DRY
LAPSE RATES LIKELY BY WEDNESDAY AFTERNOON, LOOK FOR HIGHS UP INTO
THE UPPER 70S(F) TO THE LOWER TO MID 80S(F). A GENERAL COOLING TREND
IS LIKELY THROUGH THE END OF THE WEEK AS MUCH COOLER AIR SURGES
SOUTH INTO WESTERN KANSAS IN WAKE OF THE COLD FRONTAL PASSAGE
THURSDAY. HIGHS COULD STRUGGLE TO REACH THE 70S(F) THURSDAY
DEPENDING ON ANY CLOUD COVER ASSOCIATED WITH THE COLD FRONT
AND THE TIMING OF THE PASSAGE ITSELF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM CDT TUE APR 17 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THIS FORECAST
PERIOD. WINDS WILL BECOME GUSTY FROM THE SOUTHWEST FROM LATE TUESDAY
MORNING UNTIL AROUND SUNSET AS DAYTIME MIXING OF THE LOWER ATMOSPHERE
INCREASES. FEW-SCT050 CUMULUS WILL BE POSSIBLE DURING THE AFTERNOON
MAINLY AT DODGE CITY AND HAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...JJOHNSON
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
346 AM CDT TUE APR 17 2012
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM CDT TUE APR 17 2012
PATCHY DENSE FOG HAS DEVELOPED OUT ALONG AND WEST OF A LINE FROM SCOTT
CITY AND GARDEN CITY DOWN TOWARD MEADE. MSAS/RUC ANALYSIS IS SHOWING
A SWATH OF LOW DEWPOINT DEPRESSION LINING UP WELL WITH THE FOG. SO FAR
THE FOG HAS REMAINED FAIRLY PATCHY AS INDICATED ON THE 11-3.9 MICRON
SATELLITE CHANNEL. MODEL SOUNDINGS SHOW MOISTURE TO BE VERY SHALLOW
AND THE SURFACE VISIBILITY FORECAST FROM THE HRRR IS TRENDING AWAY
FROM DEVELOPING WIDESPREAD LOW VISIBILITIES THIS MORNING. CURRENT
THINKING IS TO HANDLE THE FOG WITH A MENTION OF PATCHY DENSE IN
THE GRIDS AND NOWCAST IT THROUGH SUNRISE. IF DENSE FOG BECOMES
MORE WIDESPREAD MAY NEED TO ISSUE AN ADVISORY. THE FOG SHOULD BE
FAIRLY QUICK TO BURN OFF TODAY AS LOW LEVEL MIXING ENSUES AND
SOUTH TO SOUTHWEST WINDS INCREASE.
SHORTWAVE RIDGING OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WILL
MOVE EAST TODAY WITH ZONAL FLOW SPREADING EASTWARD FROM THE ROCKIES
TODAY AND TONIGHT. GOOD MIXING TODAY WILL RESULT IN TEMPERATURES
CLIMBING INTO THE 70S...WITH UPPER 70S IN THE WEST. THE DEEP MIXING
SHOULD PUSH RELATIVE HUMIDITY LEVELS DOWN INTO THE UPPER TEENS OVER
FAR SOUTHWEST KANSAS. THE LOW RH`S SHOULD BE ATTENUATED SOMEWHAT
BY THE ONGOING GREENUP AND INCREASED EVAPOTRANSPIRATION SO ANY
SIGNIFICANT FIRE WEATHER ISSUES ARE NOT ANTICIPATED.
SOME SCATTERED CIRRUS WILL PASS OVER WESTERN KANSAS TONIGHT AS THE
AFOREMENTIONED SHORTWAVE MOVES EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 PM CDT MON APR 16 2012
WESTERLY DOWNSLOPE FLOW BEGINS TO IMPROVE TOWARDS MID WEEK AS AN
UPPER LEVEL TROUGH EMBEDDED IN THIS FLOW MOVES QUICKLY EASTWARD
TOWARDS THE NORTHERN PLAINS. THIS UPPER LEVEL TROUGH WILL CROSS OUT
INTO THE PLAINS LATE TUESDAY AND AS IT DOES A SURFACE BOUNDARY WILL
MOVE EAST INTO WESTERN KANSAS. JET UPPER LEVEL DYNAMICS APPEAR
LACKING ACROSS WESTERN KANSAS LATE TUESDAY, HOWEVER THERE WILL BE
SOME FORCING DEVELOPING LATE DAY NEAR THIS BOUNDARY THAT WILL BE
LOCATED NEAR WAKEENEY AND DODGE CITY. AT THIS TIME PRECIPITATION
CHANCES TUESDAY NIGHT STILL APPEARS VERY LOW BASED ON THE WEAK
FORCING ALOFT AND WARMING TEMPERATURES IN THE 850-700MB LAYER WHICH
SHOULD SERVE AS A CAP. AS A RESULT WILL CONTINUE TO FAVOR A DRY
FORECAST TUESDAY NIGHT BUT GIVEN THE RETURN OF NEAR 50 DEGREE
SURFACE DEWPOINTS RETURNING ACROSS SOUTH CENTRAL KANSAS WILL
CONTINUE TO FAVOR THE WARMER PREVIOUS FORECAST FOR LOWS WHICH THE
MET NOW APPEARS TO HINTING AT.
THE NEXT IN A SERIES OF UPPER LEVEL DISTURBANCES WILL THEN CROSS OUT
INTO THE PLAINS ON LATE WEDNESDAY AS WARM AIR ADVECTION IMPROVES
NORTH OF A SURFACE BOUNDARY THAT WILL EXTEND FROM WEST TO EAST
ACROSS NORTHERN KANSAS. THIS CONVECTION SHOULD STAY NORTH OF THE I70
CORRIDOR. BASED ON THE NEW 850MB TEMPERATURE TRENDS FROM THE NAM AND
GFS WILL GO AHEAD AN WARM TEMPERATURES UP INTO THE 80 TO 85 DEGREE
RANGE FOR MUCH OF SOUTHWEST KANSAS.
BY LATE WEEK AN UPPER LEVEL RIDGE IS EXPECTED TO DEVELOP ACROSS THE
WESTERN UNITED STATES AS AN UPPER LOW NEAR THE GULF OF ALASKA BEGINS
TO DROP SOUTH/SOUTHEAST. THE NEXT UPPER LEVEL TROUGH WILL MOVE OUT
INTO THE PLAINS ON THURSDAY WHICH WILL ALLOW THE FRONT ACROSS
NORTHERN KANSAS TO CROSS INTO NORTHERN OKLAHOMA BY THURSDAY EVENING.
MOIST UPSLOPE FLOW DEVELOPING NORTH OF THIS FRONT COMBINED WITH THE
LEFT EXIT REGION OF AN UPPER LEVEL JET ROTATING AROUND THIS
DEVELOPING UPPER RIDGE WILL ENHANCE THUNDERSTORM CHANCES ACROSS MUCH
OF WESTERN KANSAS THURSDAY NIGHT. THESE PRECIPITATION CHANCES WILL
END FROM WEST TO EAST EARLY FRIDAY AS THE UPPER RIDGE LOCATED OVER
THE WEST COAST STARTS TO SHIFT EASTWARD TOWARDS THE ROCKIES. AS FOR
TEMPERATURES LATE WEEK AND OVER THE WEEKEND PERIOD...AFTER A COOL
DOWN BEHIND THE FRONT THURSDAY NIGHT AND FRIDAY A WARMING TREND WILL
BEGIN FOR THE WEEKEND PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM CDT TUE APR 17 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THIS FORECAST
PERIOD. WINDS WILL BECOME GUSTY FROM THE SOUTHWEST FROM LATE TUESDAY
MORNING UNTIL AROUND SUNSET AS DAYTIME MIXING OF THE LOWER ATMOSPHERE
INCREASES. FEW-SCT050 CUMULUS WILL BE POSSIBLE DURING THE AFTERNOON
MAINLY AT DODGE CITY AND HAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 76 49 81 53 / 0 10 0 0
GCK 74 46 81 50 / 0 0 0 0
EHA 76 47 83 51 / 0 0 0 0
LBL 77 48 84 53 / 0 10 0 0
HYS 73 49 78 52 / 0 10 0 0
P28 73 53 81 55 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...BURGERT
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1237 AM CDT TUE APR 17 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 212 PM CDT MON APR 16 2012
SYNOPSIS:
THE 16 APRIL 2012 12Z SYNOPTIC MAPS SHOWED A STRONG 125 KT TO 135 KT
300 HPA JET ACROSS MISSOURI. ANOTHER 300 HPA JET STREAK WAS LOCATED
ACROSS QUEBEC. FURTHER UPSTREAM, A 50 KT TO 70 KT 300 HPA JET WAS LOCATED
ACROSS THE PACIFIC NORTHWEST. AT 500 HPA, A MINOR SHORTWAVE TROUGH WAS
MOVING ACROSS THE ROCKIES. MOISTURE ADVECTION DOWNSTREAM OF A 536 DM
LOW WAS OBSERVED ACROSS THE UPPER GREAT LAKES AND INTO THE OHIO RIVER
VALLEY. IN ADDITION, SOME MID LEVEL MOISTURE WAS PUSHING ONSHORE ACROSS
OREGON/WASHINGTON. AT 700 HPA, A RELATIVELY COOL AND DRY AIRMASS HAS
SPREAD OVER THE PLAINS IN THE WAKE OF A DEPARTING SYSTEM. AT 850 HPA,
SOME WRAP AROUND MOISTURE WAS OBSERVED ACROSS MINNESOTA AND STRETCHING
DOWN TO EASTERN KANSAS IN ASSOCIATION WITH A LOW TO MID LEVEL CYCLONE
TO THE NORTHEAST. AT THE SFC, A COLD FRONT WAS ANALYZED FROM SE ONTARIO
TO TEXAS. ANY GULF OF MEXICO MOISTURE WAS SOUTH OF THIS BOUNDARY.
TONIGHT:
VISIBLE SATELLITE AND WSR-88D TRENDS HAVE BEEN ECHOING MODEL OUTPUT,
PARTICULARLY FROM THE HRRR. AS A RESULT, HAVE RELIED HEAVILY ON THIS
MODEL FOR TONIGHT. AN UPPER LEVEL SHORTWAVE TROUGH/400 HPA PV ANOMALY
WILL MOVE ACROSS SOUTHWEST KANSAS THIS EVENING. CONVECTION HAS FORMED
ACROSS SOUTHEAST COLORADO AS A RESULT. EVEN THOUGH DEWPOINTS ARE RUNNING
ONLY IN THE 30S DEG F RANGE, THE HRRR SHOWS SOME WEAK INSTABILITY FORMING.
THIS IS ECHOED IN FORECAST SOUNDINGS ACROSS MY COUNTY WARNING AREA.
100-300 J/KG OF CAPE ALONG WITH FAIRLY STEEP 700 HPA TO 500 HPA WILL
LEAD TO EASTWARD PROPAGATING SHOWERS AND ISOLATED THUNDERSTORMS THROUGH
THE REST OF THIS AFTERNOON AND INTO THE EARLY EVENING. SEVERE WEATHER
IS NOT EXPECTED DUE TO WEAK INSTABILITY/SHEAR. OVERNIGHT LOWS WILL BE SLIGHTLY
WARMER WITH MID 30S DEG F OUT WEST AND MID 40S DEG F ACROSS SOUTH CENTRAL
KANSAS. THE 12Z NAM WAS SHOWING INCREASING 1000-850 HPA MOISTURE, BUT
THINK THIS IS AN OUTLIER COMPARED TO THE REST OF THE MODELS. THE MAIN
IMPLICATIONS FROM THIS WOULD BE AREAS OF STRATUS AND SLIGHTLY WARMER
MINIMUMS UNDER THE CLOUD DECK. WILL HOLD OFF FOR NOW ON THIS SOLUTION.
TOMORROW:
FLAT 500 HPA RIDGING IS EXPECTED ACROSS THE ROCKIES AND HIGH PLAINS
TOMORROW. THIS WILL LEAD TO WESTERLY FLOW ALOFT AND DOWNSLOPE SOUTHWESTERLY
SURFACE TO 600 HPA WINDS. THE ATMOSPHERE BECOMES DEEPLY MIXED TO ABOUT
650 HPA WHICH SUPPORTS WARMER MAXIMUM TEMPERATURES FOR TOMORROW VIA
ADIABATIC COMPRESSIONAL WARMING. THE WIND PROFILE WITHIN THIS LAYER
IS NOT PARTICULARLY STRONG, BUT I DO THINK BREEZY CONDITIONS ARE EXPECTED
AS MIXING AND RESULTANT MOMENTUM TRANSFER DEVELOPS/CONTINUES TOMORROW.
HIGHS WILL BE IN THE 70S DEG F RANGE. NO PRECIPITATION IS EXPECTED AS
SUBSIDENCE IN THE WAKE OF THE TROUGH PREVAILS. A LEE SURFACE TROUGH
ACROSS EASTERN COLORADO WILL CONTINUE AS WELL WITH THE AFOREMENTIONED
PERPENDICULAR FLOW TO THE ROCKIES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 PM CDT MON APR 16 2012
WESTERLY DOWNSLOPE FLOW BEGINS TO IMPROVE TOWARDS MID WEEK AS AN
UPPER LEVEL TROUGH EMBEDDED IN THIS FLOW MOVES QUICKLY EASTWARD
TOWARDS THE NORTHERN PLAINS. THIS UPPER LEVEL TROUGH WILL CROSS OUT
INTO THE PLAINS LATE TUESDAY AND AS IT DOES A SURFACE BOUNDARY WILL
MOVE EAST INTO WESTERN KANSAS. JET UPPER LEVEL DYNAMICS APPEAR
LACKING ACROSS WESTERN KANSAS LATE TUESDAY, HOWEVER THERE WILL BE
SOME FORCING DEVELOPING LATE DAY NEAR THIS BOUNDARY THAT WILL BE
LOCATED NEAR WAKEENEY AND DODGE CITY. AT THIS TIME PRECIPITATION
CHANCES TUESDAY NIGHT STILL APPEARS VERY LOW BASED ON THE WEAK
FORCING ALOFT AND WARMING TEMPERATURES IN THE 850-700MB LAYER WHICH
SHOULD SERVE AS A CAP. AS A RESULT WILL CONTINUE TO FAVOR A DRY
FORECAST TUESDAY NIGHT BUT GIVEN THE RETURN OF NEAR 50 DEGREE
SURFACE DEWPOINTS RETURNING ACROSS SOUTH CENTRAL KANSAS WILL
CONTINUE TO FAVOR THE WARMER PREVIOUS FORECAST FOR LOWS WHICH THE
MET NOW APPEARS TO HINTING AT.
THE NEXT IN A SERIES OF UPPER LEVEL DISTURBANCES WILL THEN CROSS OUT
INTO THE PLAINS ON LATE WEDNESDAY AS WARM AIR ADVECTION IMPROVES
NORTH OF A SURFACE BOUNDARY THAT WILL EXTEND FROM WEST TO EAST
ACROSS NORTHERN KANSAS. THIS CONVECTION SHOULD STAY NORTH OF THE I70
CORRIDOR. BASED ON THE NEW 850MB TEMPERATURE TRENDS FROM THE NAM AND
GFS WILL GO AHEAD AN WARM TEMPERATURES UP INTO THE 80 TO 85 DEGREE
RANGE FOR MUCH OF SOUTHWEST KANSAS.
BY LATE WEEK AN UPPER LEVEL RIDGE IS EXPECTED TO DEVELOP ACROSS THE
WESTERN UNITED STATES AS AN UPPER LOW NEAR THE GULF OF ALASKA BEGINS
TO DROP SOUTH/SOUTHEAST. THE NEXT UPPER LEVEL TROUGH WILL MOVE OUT
INTO THE PLAINS ON THURSDAY WHICH WILL ALLOW THE FRONT ACROSS
NORTHERN KANSAS TO CROSS INTO NORTHERN OKLAHOMA BY THURSDAY EVENING.
MOIST UPSLOPE FLOW DEVELOPING NORTH OF THIS FRONT COMBINED WITH THE
LEFT EXIT REGION OF AN UPPER LEVEL JET ROTATING AROUND THIS
DEVELOPING UPPER RIDGE WILL ENHANCE THUNDERSTORM CHANCES ACROSS MUCH
OF WESTERN KANSAS THURSDAY NIGHT. THESE PRECIPITATION CHANCES WILL
END FROM WEST TO EAST EARLY FRIDAY AS THE UPPER RIDGE LOCATED OVER
THE WEST COAST STARTS TO SHIFT EASTWARD TOWARDS THE ROCKIES. AS FOR
TEMPERATURES LATE WEEK AND OVER THE WEEKEND PERIOD...AFTER A COOL
DOWN BEHIND THE FRONT THURSDAY NIGHT AND FRIDAY A WARMING TREND WILL
BEGIN FOR THE WEEKEND PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1237 AM CDT TUE APR 17 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THIS FORECAST
PERIOD. WINDS WILL BECOME GUSTY FROM THE SOUTHWEST FROM LATE TUESDAY
MORNING UNTIL AROUND SUNSET AS DAYTIME MIXING OF THE LOWER ATMOSPHERE
INCREASES. FEW-SCT050 CUMULUS WILL BE POSSIBLE DURING THE AFTERNOON
MAINLY AT DODGE CITY AND HAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 48 80 53 75 / 10 0 0 20
GCK 45 80 50 73 / 0 0 0 20
EHA 46 82 51 75 / 0 0 0 30
LBL 47 83 53 76 / 10 0 0 20
HYS 48 77 52 71 / 10 0 10 10
P28 52 80 55 77 / 10 0 0 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...BURGERT
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS JACKSON KY
213 AM EDT TUE APR 17 2012
.UPDATE...
ISSUED AT 213 AM EDT TUE APR 17 2012
OTHER THAN THE ADJUSTMENTS TO THE HOURLY TEMP CURVES MAINLY TO
ACCOUNT FOR COLDER VALLEY TEMPS IN SOME PLACES...VERY LITTLE CHANGE
WAS NEEDED AT THIS POINT FOR THE OVERNIGHT PERIOD. THE LATEST WRF RUN
AND 21Z SREF AS WELL AS SOME OF THE HRR RUNS SUPPORT AN ISOLATED
SHOWER OR PERHAPS PATCHY LIGHT RAIN NEAR THE KY/VA/TN TRI STATE AREA
LATER ON TONIGHT INTO EARLY ON TUE.
UPDATE ISSUED AT 906 PM EDT MON APR 16 2012
SHOWERS AND TSTORMS THAT DEVELOPED ALONG THE FRONT ARE NOW EXITING
OUR VA BORDER COUNTIES. THE PAST COUPLE RUNS OF THE HRRR BRING
ANOTHER AREA OF SHOWERS NORTHEAST FROM NORTHERN ALABAMA INTO FAR
SOUTHEAST KENTUCKY TOWARDS DAWN SO WILL LINGER A 20 POP OVERNIGHT
INTO EARLY TUESDAY MORNING FOR BELL AND HARLAN COUNTIES. THE REST OF
THE AREA SHOULD REMAIN DRY. THE REMAINDER OF THE FORECAST LOOKS ON
TRACK WITH JUST SOME FINE TUNING OF SKY/TEMPS/DEWS NEEDED. HAVE A
GOOD NIGHT.
UPDATE ISSUED AT 523 PM EDT MON APR 16 2012
ILL DEFINED COLD FRONT IS WORKING ACROSS THE AREA WITH ANOTHER TROUGH
EVIDENT BY A WIND SHIFT ENTERING NORTH CENTRAL KENTUCKY AT THIS TIME.
RADAR RETURNS NEAR LAKE CUMBERLAND ARE LIKELY VIRGA AND ANY
ADDITIONAL SHOWER ACTIVITY THIS EVENING SHOULD BE ISOLATED AT BEST
AND HAVE TRIMMED BACK NEAR TERM POPS TO FIT THAT SCENARIO.
OTHERWISE...HAVE JUST PROVIDED SOME TWEAKS TO TEMPS/DEWPOINTS/SKY
COVER/WINDS TO FIT CURRENT AND EXPECTED NEAR TERM CONDITIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 215 PM EDT MON APR 16 2012
WAVE OF SHRA CROSSING ERN KY THIS AFTERNOON. PROJECTING THE TRAILING
EDGE OF THE PCPN HAS IT JUST EAST OF THE STATE BY 8 PM. THIS IS WELL
REFLECTED IN NEARLY ALL THE MODELS. CLOUD COVER EXTENDS FROM MI TO TX
SO CLEARING WILL TAKE A WHILE TONIGHT AND WILL KEEP CONSIDERABLE
CLOUDS IN FCST THRU THE OVERNIGHT PERIOD TONIGHT. COOLER AIR WILL
THEN CYCLE BACK INTO THE AREA FOR TUE AS TEMPS BEHIND THE FRONT ARE
10-15 DEG COOLER THAN PRE FRONTAL. EXPECTING HIGHS ON TUE ONLY TO
REACH THE MID 60S. THE CURRENT FRONT WILL STALL TO OUR SOUTH
THRU TUE AND THEN A WAVE IN THE GULF WILL SLIDE EAST AND WAVE THE
BOUNDARY BACK TO THE NORTH LATE TUE NIGHT WITH CHANCE POPS IN OUR
SERN COUNTIES. THE CHANCE OF RAIN DROPS OFF QUICKLY AS YOU HEAD NORTH
AND THE BLUEGRASS COUNTIES IN OUR NORTHERN FCST AREA SHOULD BE RAIN
FREE. THE CLOUD COVER THAT ACCOMPANIES THE RAIN TUE NIGHT WILL KEEP
OVERNIGHT LOWS A BIT WARMER IN THE SOUTH. THE PARTLY CLOUDY SKIES AND
LIGHT WINDS TUE NIGHT WILL ALLOW TEMPS TO DROP INTO THE UPPER 40S
SOUTH AND MID 40S NORTH...WHICH IS ABOUT NORMAL FOR THIS TIME OF THE
YEAR.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 300 PM EDT MON APR 16 2012
THE EXTENDED FORECAST PERIOD BEGINS ON WEDNESDAY WITH A PROGRESSIVE
MOSTLY ZONAL PATTERN IN PLACE. A DEVELOPING SHORTWAVE LOCATED OVER
THE SOUTHEAST EXITS THE EAST COAST BY WEDNESDAY NIGHT. AT THE
SURFACE...DURING THE DAY WEDNESDAY...A LOW DEVELOPS AND MOVES NE OFF
THE EAST COAST. EASTERN KENTUCKY WILL STILL STAND TO RECEIVE SOME
DEFORMATION PRECIP ON THE BACK EDGE OF THE SYSTEM AS IT EXITS OFF TO
THE NORTHEAST. WEAK RIDGING THEN WILL KEEP EASTERN KENTUCKY DRY FOR
THE THURSDAY THROUGH FRIDAY NIGHT TIME FRAME. BY FRIDAY NIGHT...THE
UPPER LEVEL PATTERN GAINS SOME AMPLITUDE AND BECOMES MERIDIONAL AS BY
SATURDAY...A TROUGH DIGS INTO THE SOUTH CENTRAL PLAINS WHILE RIDGING
BUILDS IN THE SOUTHWEST AND OFF THE EAST COAST. BY LATE
SATURDAY...SURFACE LOW PRESSURE REDEVELOPS ALONG A NEARLY STALLED
BOUNDARY DRAPED FROM THE LOWER MS VALLEY NORTHEAST INTO THE OH
VALLEY. THE SYSTEM STRENGTHENS AS IT BEGINS TO MOVE UP THE EAST
COAST. BOTH THE EURO AND GFS PAINT THIS SIMILAR SCENARIO.
AFTER RUNNING THE INITIALIZATION...HAD TO TRIM BACK POPS FOR THE
APPROACHING FRONT FRIDAY NIGHT. THE DEVELOPING AMPLITUDE OF THE
PATTERN WOULD SUGGEST A SLOWING TO THE APPROACH OF THE FRONT AND THE
12Z GFS AND 00Z EURO AGREE TO THIS SO BROUGHT THE BULK OF THE POPS
INTO THE AREA BY 12Z SATURDAY. WITH BOTH THE GFS AND THE EURO CLOSING
OFF THE UPPER LOW OVER THE EAST TOWARD THE END OF THE PERIOD AND THE
SURFACE LOW TRANSITIONING TO A COASTAL LOW TYPE SET UP...KEPT POPS IN
THE FORECAST FOR THE REST OF THE EXTENDED. OTHERWISE...ANY OTHER
ADJUSTMENTS WERE FOR TERRAIN AND MATCHING UP WITH NEIGHBORING
OFFICES.
WITH THE SOUTHERLY FLOW AHEAD OF THE LOW FOR THE FIRST FEW DAY OF
THE EXTENDED...HIGHS WILL BE AROUND IF NOT A LITTLE ABOVE NORMAL. BY
DAYS 6 AND 7...TEMPERATURES WILL DROP BY 5 TO 10 DEGREES BELOW NORMAL
AS AT THIS POINT...MODELS ARE INDICATING QUITE A BIT OF COLDER AIR
BEHIND THIS SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 213 AM EDT TUE APR 17 2012
A COLD FRONT WILL STALL OUT TO OUR SOUTHEAST OVER THE NEXT 6 TO 12
HRS. A WAVE OF LOW PRESSURE WILL FORM AND MOVE ALONG THIS FRONT ON
TUESDAY INTO TUE NIGHT KEEPING CLOUDS RATHER PROLIFIC DURING THE
PERIOD...ALTHOUGH CIGS WILL BE VFR. OTHER THAN SOME ISOLATED SHOWERS
OR PATCHY LIGHT RAIN BETWEEN 9Z AND 15Z NEAR 1A6...LIGHT RAIN IS NOT
EXPECTED TO ACROSS EAST KY UNTIL AFTER 22Z NEAR THE TN AND VA BORDERS.
THIS THREAT FOR SOME LIGHT RAIN WILL THEN SPREAD NW THROUGH THE END
OF THE PERIOD...BUT CIGS WITH THIS SHOULD STILL REMAIN VFR. GENERALLY
LIGHT NORTH TO NORTHEASTERLY WINDS ARE EXPECTED THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...DUSTY
LONG TERM....SHALLENBERGER
AVIATION...JP
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
333 PM EDT TUE APR 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR A DRY FORECAST FOR THE MAJORITY OF
THE AREA THROUGH FRIDAY. THE EXCEPTION WILL BE THE CHANCE OF
SHOWERS AS A WEAK LOW PRESSURE SYSTEM PASSES SOUTHEAST OF THE AREA
ON WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL RETURN
THE CHANCE OF SHOWERS AND THUNDERSTORMS LATE FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A
SOUTHWESTERLY FLOW AHEAD OF A BROAD AND WEAK SHORT WAVE TROUGH
ACROSS THE GREAT LAKES. AT THE SURFACE, HIGH PRESSURE IS CENTERED
ACROSS LAKE MICHIGAN AND EXTENDS ACROSS THE OHIO VALLEY. MID TO
UPPER LEVEL MOISTURE CONTINUES TO FILTER IN FROM THE SOUTHWEST,
ALLOWING FOR MOSTLY CLOUDY SKIES.
THE MID-LEVEL FLOW WILL FLATTEN AND BECOME MORE ZONAL THROUGH
TONIGHT, WITH HIGH PRESSURE SLIDING ACROSS THE GREAT LAKES. THE LOBE
OF HIGH PRESSURE IS PROGGED TO BE CENTERED ACROSS LAKE ONTARIO BY
12Z WEDNESDAY. 500-250MB LAYER MOISTURE SHOULD PROVIDE ENOUGH CLOUD
COVERAGE TO LIMIT RADIATIONAL COOLING. LOWS TONIGHT ARE CLOSER TO
THE WARMER MAV GUIDANCE, RANGING FROM THE MID 30S ALONG THE I-80
CORRIDOR TO THE MID 40S ACROSS NORTH-CENTRAL WV. THE I-80 CORRIDOR
IS CURRENTLY MARGINALLY WARMER THAN FREEZING FOR LOWS, SO WILL NOT
ISSUE A FREEZE WARNING AT THIS TIME.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
THERE IS GFS/ECMWF/NAM AGREEMENT THAT A SHORT WAVE WILL PASS
SOUTHEAST OF THE AREA WITH A WEAK SURFACE LOW ON WEDNESDAY. TO THE
NORTHWEST, A SURFACE LOW WILL MOVE INTO THE NORTHERN GREAT LAKES,
PUSHING A WARM FRONT NORTHWARD INTO THE REGION. AT THIS TIME, IT
APPEARS THAT THE UPPER OHIO VALLEY WILL STAY MOSTLY DRY IN BETWEEN
THESE FEATURES ON WEDNESDAY. THERE IS STILL A LITTLE UNCERTAINTY AS
TO WHETHER PRECIP ON THE NORTHERN EDGE OF THE SHORT WAVE CAN MAKE IT
INTO THE SOUTHEASTERN RIDGES WEDNESDAY AFTERNOON, SO HAVE LEFT A
SCHC THERE. WITH ABUNDANT SUNSHINE ANTICIPATED AS A DEEP LAYER OF
DRY AIR CROSSES THE AREA, TEMPS ARE FORECAST TO RECOVER NICELY AFTER
THE COLD START. HIGHS ARE FORECAST TO BE AROUND 5 DEGREES ABOVE
SEASONAL NORMALS.
GFS/ECMWF REMAIN IN AGREEMENT WEDNESDAY NIGHT THROUGH FRIDAY
AFTERNOON. THE NAM IS CONSIDERED TO BE AN OUTLIER, BRINGING PRECIP IN
EARLIER IN THE DAY. THE FORECAST LEANS TO THE SLOWER ECMWF/GFS
SOLUTIONS, KEEPING THE FORECAST DRY MOST OF THE DAY FRIDAY AHEAD
OF A COLD FRONT APPROACHING FROM THE WEST. WITH THE WARM FRONT
NORTH OF THE AREA, TEMPERATURES WILL BECOME PROGRESSIVELY WARMER
THURSDAY INTO FRIDAY, WARMING TO 10 TO 15 DEGREES ABOVE NORMAL FOR
HIGHS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT WILL SLOWLY ADVANCE EASTWARD ACROSS THE REGION FRIDAY
NIGHT THROUGH SATURDAY NIGHT. FORECAST A SWATH OF LIKELY POPS FOR
SHOWERS TO SHIFT SOUTHEASTWARD ACROSS THE FORECAST AREA ON
SATURDAY...WITH PRECIPITATION TAPERING TO SCATTERED COVERAGE DURING
SATURDAY NIGHT.
MODELS SHOW A CLOSED UPPER LOW FORMING AT THE BOTTOM OF A SHARP
TROUGH AND RIDING EAST ALONG THE GULF COAST SATURDAY AND SUNDAY.
LATEST MODEL RUNS STILL DIFFER ON THE TRACK OF A SURFACE LOW MOVING
ALONG THE EASTERN SEABOARD AND THE WESTERN EXTENT OF PRECIPITATION
MONDAY AND TUESDAY. FORECAST POPS ARE CLOSE TO HPC NUMBERS WITH HIGH
END CHANCE POPS SUNDAY TAPERING TO AROUND 30 PERCENT ALONG THE
RIDGES AND SLIGHT CHANCE FURTHER WEST BY MONDAY MORNING.
TEMPERATURES ARE FORECAST TO COOL TO BETWEEN 5 AND 10 DEGREES BELOW
NORMAL BY EARLY NEXT WEEK.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL DRIFT EAST ACROSS THE GREAT LAKES REGION
THROUGH WEDNESDAY. VFR CONDITIONS AND LIGHT WINDS ARE FORECAST
THROUGH THE TAF PERIOD...WITH AREAS OF MIDDLE AND HIGH CLOUDS MOVING
ACROSS THE UPPER OHIO VALLEY.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
VFR WEATHER SHOULD PREVAIL INTO FRIDAY UNDER A WEAK RIDGE.
RESTRICTIONS WILL BE LIKELY IN SHOWERS LATE FRIDAY NIGHT THROUGH
SUNDAY AS A FRONTAL BOUNDARY SLOWLY CROSSES THE OHIO VALLEY AND A
SURFACE LOW TRACKS FROM THE GULF COAST TO ALONG THE CAROLINA
COAST.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
209 PM EDT TUE APR 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR A DRY FORECAST FOR THE MAJORITY OF
THE AREA THROUGH FRIDAY. THE EXCEPTION WILL BE THE CHANCE OF
SHOWERS AS A WEAK LOW PRESSURE SYSTEM PASSES SOUTHEAST OF THE AREA
ON WEDNESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL RETURN
THE CHANCE OF SHOWERS AND THUNDERSTORMS LATE FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
INCREASE THE CLOUD COVERAGE THIS AFTERNOON AND OVERNIGHT.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A SOUTHWESTERLY FLOW WITH A BROAD AND WEAK TROUGH ACROSS THE
GREAT LAKES. AT THE SURFACE, HIGH PRESSURE IS CENTERED ACROSS LAKE
MICHIGAN AND EXTENDS ACROSS THE OHIO VALLEY. MID TO UPPER LEVEL
MOISTURE IS FILTERING IN FROM THE SOUTHWEST, ALLOWING FOR CLOUD
COVERAGE TO INCREASE TO MOSTLY CLOUDY.
MOISTURE ALOFT WILL CONTINUE TO FILTER IN FROM THE SOUTHWEST AND ALLOW
FOR MOSTLY CLOUDY SKIES. TEMPS TODAY ARE NEAR LAMP GUIDANCE, WITH
HIGHS RANGING FROM THE UPPER 50S ACROSS THE EASTERN RIDGES TO THE
MID 60S SOUTHWEST OF PITTSBURGH.
MID-LEVEL FLOW WILL FLATTEN AND BECOME MORE ZONAL THROUGH
TONIGHT, WITH HIGH PRESSURE SLIDING ACROSS THE GREAT LAKES. THE
LOBE OF HIGH PRESSURE IS PROGGED TO BE CENTERED ACROSS LAKE
ONTARIO BY 12Z WEDNESDAY. 500-250MB LAYER MOISTURE SHOULD PROVIDE
ENOUGH CLOUD COVERAGE TO LIMIT RADIATIONAL COOLING. LOWS TONIGHT
ARE CLOSER TO THE WARMER MAV GUIDANCE, RANGING FROM THE MID 30S
ALONG THE I-80 CORRIDOR TO THE MID 40S ACROSS NORTH-CENTRAL WV.
THE I-80 CORRIDOR IS CURRENTLY MARGINALLY WARMER THAN FREEZING FOR
LOWS, SO WILL NOT ISSUE A FREEZE WARNING AT THIS TIME.
&&
.SHORT TERM /WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS SURFACE HIGH PRESSURE, COMING EAST
FROM IOWA, CONTINUING DRY CONDITIONS FOR MOST OF THE UPPER OHIO
VALLEY THROUGH WEDNESDAY.
A COUPLE SREF MEMBERS SHOW LOW PRESSURE MOVING NORTHEASTWARD THROUGH
THE MID-ATLANTIC STATES AND PERHAPS SPREAD ISOLATED LIGHT SHOWERS
ACROSS THE WV-MD MOUNTAINS DAYTIME WEDNESDAY.
TEMPERATURES SHOULD CONTINUE TO REMAIN CLOSE TO NORMAL VALUES BASED
OFF OF THE MOST RECENT MAV/MEX GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
RECENT SREF MODEL OUTPUT SHOWS EASTBOUND LOW PRESSURE THROUGH THE
GREAT LAKES PERHAPS LAYING A STALLED COLD FRONT ACROSS NORTHERN
PENNSYLVANIA THURSDAY. EXPECT LITTLE SHOWER DEVELOPMENT BUT AN
INCREASE IN CLOUDS THURSDAY INTO FRIDAY.
BLEND OF RECENT ECMWF, GFS, AND CMC, SHOW A BETTER DEVELOPED LOW
PRESSURE SYSTEM, COMING EAST FROM THE NORTHERN ROCKIES, WILL PROVIDE
THE UPPER OHIO VALLEY WITH SHOWERS AND POSSIBLE THUNDERSTORMS LATE
FRIDAY INTO SUNDAY.
GFS MOS AND NAEFS MEDIAN VALUES SHOW WARMER THAN NORMAL TEMPERATURES
INTO SATURDAY, FOLLOWED BY A POST-SYSTEM COOL DOWN TO SEASONABLE
TEMPERATURES SUNDAY AND MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
EXPECT VFR TO CONTINUE THROUGH TONIGHT, WITH LITTLE MORE THAN
PASSING STRANDS OF ALTOCUMULUS AND CIRRUS.
SURFACE WINDS WILL REMAIN NORTHWESTERLY 8 TO 15 KTS INTO EVENING,
THEN DECREASE TO 5 KTS.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
VFR INTO FRIDAY. RESTRICTIONS LIKELY FRIDAY NIGHT AND SATURDAY FROM
PREFRONTAL SHOWERS AND POSSIBLE THUNDERSTORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1050 AM EDT TUE APR 17 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY WEATHER THROUGH FRIDAY. A COLD
FRONT APPROACHING FROM THE WEST WILL RETURN THE CHANCE OF SHOWERS
AND THUNDERSTORMS LATE FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A
SOUTHWESTERLY FLOW WITH A BROAD AND WEAK TROUGH ACROSS THE GREAT
LAKES. AT THE SURFACE, HIGH PRESSURE IS CENTERED ACROSS LAKE
MICHIGAN AND EXTENDS ACROSS THE OHIO VALLEY. MID TO UPPER LEVEL
MOISTURE IS FILTERING IN FROM THE SOUTHWEST, ALLOWING FOR PARTLY
CLOUDY SKIES.
MOISTURE ALOFT WILL CONTINUE TO FILTER IN FROM THE SOUTHWEST AND ALLOW
FOR PARTLY CLOUDY SKIES TODAY. TEMPS TODAY ARE NEAR LAMP
GUIDANCE, WITH HIGHS RANGING FROM THE MID 50S ALONG THE I-80
CORRIDOR AND EASTERN RIDGES TO THE MID 60S SOUTHWEST OF
PITTSBURGH.
MID-LEVEL FLOW WILL FLATTEN AND BECOME MORE ZONAL THROUGH
TONIGHT, WITH HIGH PRESSURE SLIDING ACROSS THE GREAT LAKES. THE
LOBE OF HIGH PRESSURE IS PROGGED TO BE CENTERED ACROSS LAKE
ONTARIO BY 12Z WEDNESDAY. 500-250MB LAYER MOISTURE SHOULD PROVIDE
ENOUGH CLOUD COVERAGE TO LIMIT RADIATIONAL COOLING. LOWS TONIGHT
ARE CLOSER TO THE WARMER MAV GUIDANCE, RANGING FROM THE MID 30S
ALONG THE I-80 CORRIDOR TO THE MID 40S ACROSS NORTH-CENTRAL WV.
THE I-80 CORRIDOR IS CURRENTLY MARGINALLY WARMER THAN FREEZING FOR
LOWS, SO WILL NOT ISSUE A FREEZE WARNING AT THIS TIME.
&&
.SHORT TERM /WEDNESDAY/...
RECENT SREF MODEL OUTPUT SHOWS SURFACE HIGH PRESSURE, COMING EAST
FROM IOWA, CONTINUING DRY CONDITIONS FOR MOST OF THE UPPER OHIO
VALLEY THROUGH WEDNESDAY.
A COUPLE SREF MEMBERS SHOW LOW PRESSURE MOVING NORTHEASTWARD THROUGH
THE MID-ATLANTIC STATES AND PERHAPS SPREAD ISOLATED LIGHT SHOWERS
ACROSS THE WV-MD MOUNTAINS DAYTIME WEDNESDAY.
TEMPERATURES SHOULD CONTINUE TO REMAIN CLOSE TO NORMAL VALUES BASED
OFF OF THE MOST RECENT MAV/MEX GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
RECENT SREF MODEL OUTPUT SHOWS EASTBOUND LOW PRESSURE THROUGH THE
GREAT LAKES PERHAPS LAYING A STALLED COLD FRONT ACROSS NORTHERN
PENNSYLVANIA THURSDAY. EXPECT LITTLE SHOWER DEVELOPMENT BUT AN
INCREASE IN CLOUDS THURSDAY INTO FRIDAY.
BLEND OF RECENT ECMWF, GFS, AND CMC, SHOW A BETTER DEVELOPED LOW
PRESSURE SYSTEM, COMING EAST FROM THE NORTHERN ROCKIES, WILL PROVIDE
THE UPPER OHIO VALLEY WITH SHOWERS AND POSSIBLE THUNDERSTORMS LATE
FRIDAY INTO SUNDAY.
GFS MOS AND NAEFS MEDIAN VALUES SHOW WARMER THAN NORMAL TEMPERATURES
INTO SATURDAY, FOLLOWED BY A POST-SYSTEM COOL DOWN TO SEASONABLE
TEMPERATURES SUNDAY AND MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
EXPECT VFR TO CONTINUE THROUGH TONIGHT, WITH LITTLE MORE THAN
PASSING STRANDS OF ALTOCUMULUS AND CIRRUS.
SURFACE WINDS WILL REMAIN NORTHWESTERLY 8 TO 15 KTS INTO EVENING,
THEN DECREASE TO 5 KTS.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
VFR INTO FRIDAY. RESTRICTIONS LIKELY FRIDAY NIGHT AND SATURDAY FROM
PREFRONTAL SHOWERS AND POSSIBLE THUNDERSTORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
114 PM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 443 AM EDT TUE APR 17 2012
00Z RAOBS/LATEST WV IMAGERY AND LATEST RUC ANALYSIS SHOW SHRTWV
RESPONSIBLE FOR WINTRY MIX/GUSTY WINDS YDAY SHEARING ENEWD OVER
ONTARIO ON NW FLANK OF SHARP UPR RDG OFF THE SE COAST. ALTHOUGH
ASSOCIATED SFC LO IS WEAKENING AND MOVING QUICKLY TO THE E THRU
QUEBEC...SOME SHSN ARE FALLING OVER THE NCNTRL AND E AS OF MIDNGT
UNDER THE WEAKENING BUT LINGERING CYC NW FLOW LEFT IN ITS WAKE.
00Z H85 TEMPS AS LO AS -11C PER RUC ANALYSIS AND CONSIDERABLE
LLVL MSTR/INVRN BASE ARND H85 SHOWN ON THE 00Z APX RAOB ARE
CONDITIONS CONDUCIVE FOR THIS BIT OF LATE SEASON LES AND EXTENSIVE
LK SC. UNDER THE H85 THERMAL TROF...SFC TEMPS ARE QUITE CHILLY WITH
TEMPS GENERALLY IN THE 20S. ALTHOUGH PTCHY LO CLDS ARE STILL PRESENT
AS FAR W AS THE MN ARROWHEAD...ANY LINGERING PCPN IS ENDING OVER THE
W WITH APRCH OF TRAILING HI PRES RDG AND VERY DRY AIR SHOWN ON THE
00Z INL RAOB /PWAT 0.13 INCH/. LOOKING FARTHER W...AN UPPER RDG IS
BLDG INTO THE PLAINS WITH 12Z-24Z H3 RISES ARND 150M OVER THE NRN
PLAINS AND S OF NRN BRANCH TROF OVER CENTRAL CANADA. 00Z BISMARCK
RAOB DOES SHOW SOME MSTR THAT SUPPORTED A GOOD AMOUNT OF SC IN THE
NRN PLAINS YDAY. ANOTHER SHRTWV IS MOVING ONSHORE IN THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 443 AM EDT TUE APR 17 2012
MAIN FCST CONCERNS DURING THIS TIME ARE PCPN TRENDS EARLY THIS
MRNG...TEMPS TODAY...AND THEN PCPN CHCS LATE TNGT THRU WED
ASSOCIATED WITH SHRTWV NOW MOVING THRU THE PAC NW.
EARLY THIS MRNG...AS SHRTWV/SFC LO TO THE E CONTINUE TO SLIDE AWAY
AND HI PRES BUILDS INTO THE WRN CWA BY 09Z UNDER STEADY H5
RISES/DNVA THAT IS FCST TO LOWER INVRN BASE TO UNDER 3K FT AT ERY BY
09Z. SO ALTHOUGH QUITE A BIT OF SC WILL LINGER...EXPECT ANY -SHSN TO
BE OVER BY 12Z. LINGERING SC OVER MUCH OF THE CWA WL LIMIT
ADDITIONAL DIURNAL TEMP DROP.
TODAY...WITH HI PRES/DRY AIRMASS PUSHING E ACROSS THE CWA...EXPECT
LAKE EFFECT SC IN THE MRNG TO DISSIPATE IN THE PRESENCE OF DAYTIME
HEATING AND WEAKENING CYC FLOW. BUT WITH HINT OF LINGERING H85
THERMAL TROF AND ARRIVAL OF SOME MSTR SHOWN ON THE 00Z BISMARCK
RAOB...MORE DIURNAL CU/SC SHOULD DVLP OVER MAINLY THE W HALF
INTERIOR INLAND AWAY FM LK BREEZES THAT FORM IN THE RELATIVELY WEAK
PRES GRADIENT. MIXING TO H85-8 ON NAM FCST SDNGS YIELD HI TEMPS
RANGING FM ARND 40 AT ERY TO THE UPR 40S NEAR THE WI BORDER. WITH LK
BREEZE FORMATION...EXPECT COOLER READINGS NEAR THE LK SHORES.
TNGT...LATEST NUMERICAL MODELS IN GOOD AGREEMENT SHOWING SHRTWV NOW
IN THE PAC NW/ACCOMPANYING SFC LO MOVING THRU THE NRN PLAINS AND
INTO NE MN BY 12Z WED...WITH WAD PCPN IN ADVANCE OF THIS FEATURE
OVERSPREADING THE W HALF OF UPR MI BY SUNRISE. MAIN FORCING
MECHANISMS LOOK TO BE VIGOROUS UPR DVGC IN LEFT EXIT OF SUPPORTING
H3 JET MAX/VIGOROUS ISENTROPIC ASCENT POWERED BY H85 SW 50-60KT
WINDS/VIGOROUS H85-7 FGEN IN ADVANCE OF ATTENDANT WARM FNT. OPTED TO
BUMP POPS UP TO CATEGORICAL OVER THE W AFT 06Z GIVEN THESE POTENT
DYNAMICS/IMPRESSIVE DEEP LYR QVECTOR CNVGC/MODEL CONSISTENCY ON
GENERATING PCPN IN THIS AREA. ALTHOUGH FCST H100-85 THKNS AS HI AS
1320-1335M IN ADVANCE OF PCPN ARRIVAL...RAPID ARRIVAL OF WAD
CLD...FASTER ADVECTION OF HIER LLVL SPECIFIC HUMIDITY THAN EARLIER
FCSTS INDICATED...ONSET OF STRONGER WINDS INDICATE PCPN SHOULD BE
ALL RA...INITIAL RELATIVE DRYNESS OF LLVLS THAT LOWERS WBLB TO BLO
32 AT THE SFC SUPPORTS MAINTAING A MENTION OF A BIT OF -FZRA AT THE
ONSET OF THE RA SHIELD OVER THE INTERIOR. ANY ICING WOULD BE
INSIGNIFICANT DUE TO STEADY WARMING SOON AFT PCPN ARRIVAL. UTILIZED
A NON-DIURNAL TEMP CURVE TO HANDLE TEMP TRENDS. TEMPS WL BE LOWEST
AND SINK BLO 32 OVER THE E...BUT PCPN WL NOT GET THERE BEFORE
SUNRISE. ALTHOUGH GFS/NAM SHOW LAPSE RATES NOT MUCH STEEPER THAN
MOIST ADIABATIC/ MUCAPE UNDER 50 J/KG...RETAINED MENTION OF SCHC TS
GIVEN VIGOROUS DYNAMICS/STRONG WARMING AT H85.
WED...SINCE THE SHRTWV/SFC LO AND ACCOMPANYING DYNAMICS ARE FCST TO
MOVE STEADILY EWD...EXPECT THE HIER POPS TO SHIFT W-E THRU THE CWA.
THERE IS AN INDICATION THAT WITH AFTN DRYING/RETURN OF SOME
SUNSHINE...THERE WL BE ENUF DESTABILIZATION TO RESULT IN SOME
SHRA/TS OVER THE INTERIOR W HALF. BUT FCST LARGER SCALE QVECTOR DVGC
IN THE WAKE OF THE DISTURBANCE THAT SHARPENS THE MID LVL INVRN
SHOULD LIMIT THIS CHC. WL RETAIN NO HIER THAN SCHC-CHC POPS OVER THE
INTERIOR FOLLOWING THE DEPARTURE OF THE DEEPER MSTR GIVEN FCST KINX
BLO 20 ON NAM FCST SDNGS.
WED NGT...HI PRES BLDG INTO AREA UNDER DNVA IN THE WAKE OF THE
DEPARTING SHRTWV WL BRING DRY WX TO THE CWA. ALTHOUGH THERE COULD BE
SOME LK CLDS IN THE ABSENCE OF DAYTIME HEATING WITH H85 TEMPS
SINKING AS LO AS -6C...DRYNESS OF THE INCOMING AIRMASS AND LLVL ACYC
FLOW SUGS THIS POTENTIAL IS LO.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 443 AM EDT TUE APR 17 2012
AFTER PASSAGE OF SHORTWAVE TROUGH...UPPER AIR PATTERN FOR THURSDAY
FEATURES INCREASING CONFLUENT FLOW EARLY ON. PRIMARY RESULT IS SFC
RIDGE OVR CNTRL CANADA BUILDING INTO UPPER LAKES REGION THROUGH THE
DAY AS SFC FRONTAL BOUNDARY SETTLES INTO CNTRL GREAT LAKES TO
NORTHERN FRINGE OF OHIO VALLEY. BY THURSDAY AFTN...H85 BAROCLINIC
ZONE FCST TO BE MORE FM NORTHERN IOWA INTO CNTRL LOWER MICHIGAN.
NEXT SHORTWAVE TROUGH ALREADY EMERGING ONTO THE PLAINS BY DAYBREAK
THURSDAY WILL BE QUICKLY HEADING INTO WESTERN GREAT LAKES BY AFTN.
MODELS REMAIN AT ODDS ON HOW FAR NORTH TO BRING SFC-H85 LOW PRESSURE
BY LATE THURSDAY AFTN. OPERATIONAL GFS AND GFS ENSEMBLES KEEP THE
LOW TIED TO SFC FRONT THAT WILL BE OVER SOUTHERN PORTIONS OF GREAT
LAKES AND INTO NORTHERN OHIO VALLEY. GFS HAS SHOWED A MORE SOUTHERN
SUPPRESSED SOLUTION FOR THIS SYSTEM QUITE SOME TIME NOW. OTHER
EXTREME IS ECMWF AND ASSOCIATED ENSEMBLES WHICH RIDE SFC LOW
MORE ALONG H85 THERMAL GRADIENT OVR WI AND LOWER MI. THUS...ECMWF
INSISTS THAT MAJORITY OF CWA EXCEPT FOR PERHAPS FAR NW WOULD BE
IMPACTED BY PRECIPITATION. NAM/UKMET AND THE CANADIAN REPRESENT
MIDDLE GROUND CLIPPING SOUTHERN AND EASTERN CWA WITH PRECIPITATION
BUT OTHERWISE KEEPING CWA DRY.
IT IS BECOMING APPARENT THAT A BIG KEY FOR THIS SYSTEM IS EXTENT OF
DRY AIR THAT LURKS AHEAD OF THE SYSTEM AS LATE AS THURSDAY AFTN.
FCST SOUNDINGS FM GFS/ECMWF AND NAM SHOW POCKET OF DRY AIR LINGERING
BTWN H9 AND H7. NAM IS QUITE EMPHATIC WITH THE DRY AIR SHOWING H85
AT 18Z THURSDAY AOB -20C OVR MUCH OF THE CWA BEFORE ERODING THIS
SOMEWHAT BY 00Z FRIDAY. DRY AIR FLOWING IN ON NORTHEAST SFC WINDS FM
LARGE HIGH PRESSURE OVR NORTHERN ONTARIO AND FACT THAT RIBBON OF
SHARP FRONTOGENEIS IS FCST OVR UPR LAKES SUPPORTS IDEA THAT THERE
COULD BE VERY SHARP CUTOFF TO NORTHERN EXTENT OF PRECIPITATION.
INTERESTING THAT EVEN THE ECMWF SHOWS H85 FGEN AXIS JUST SOUTH OF
CWA WITH H7 FGEN AXIS ROUGHLY FM IMT TO SSM ON THURSDAY NIGHT.
IMAGINE MOST OF THE PRECIPITATION FM THE SYSTEM WILL OCCUR ON THE
SOUTHERN EDGE OF THE H7 FGEN...SO THAT WOULD LEAVE FAR SOUTHEAST CWA
IN LINE TO SEE MOST PRECIPITATION WITH THE SYSTEM. MAJORITY OF THE
PRECIP WOULD PROBABLY FALL THURSDAY NIGHT AS THE LEADOFF FORCING ON
THURSDAY WILL ONLY SERVE TO MOISTEN THE VERY DRY LOW-LEVELS. PREV
FCST MATCHES UP WITH THIS THINKING WELL KEEPING HIGHEST POPS NEAR LK
MICHIGAN ON THURSDAY NIGHT. THIS ALSO MATCHES SURROUNDING WFOS VERY
NICELY.
NOW ON TO PTYPE. LOOKS LIKE SNOW FOR MUCH OF THE EVENT. NORTHEAST
SFC WINDS PROBABLY MITIGATE WARMING EFFECT OFF LK MICHIGAN FOR ALL
BUT SOUTHERN MNM COUNTY. ALSO LARGER SCALE FORCING/INTENSE
PRECIPITATION RATES MOST LIKELY WILL OVERWHELM A MINIMAL NEAR SFC
WARM LAYER. 1000-850MB THICKNESSES AND H85 TEMPS FM ECMWF SUPPORT
MAINLY SNOW BY LATER EVENING INTO THE OVERNIGHT HOURS. WWD GRAPHICS
FM HPC INDICATE SEVERAL INCHES OF SNOW POSSIBLE OVR SOUTH AND EAST
CWA ONCE THE RAIN CHANGES TO SNOW. EVEN THOUGH THIS COULD OCCUR IN
NON-GFS SOLUTIONS...REALLY TOUGH TO GO WITH MORE THAN CHANCY POPS
WITH DOWNPLAYED QPF/SNOW AT THIS POINT GIVEN PERSISTENT GFS SOUTHERN
SOLUTION AND FACT THAT SHARP CUTOFF COULD ULTIMATELY PUSH MOST OF
THE PRECIPITATION TO THE SOUTH OF CWA. SYSTEM IS CURRENTLY CHURNING
ACROSS EASTERN PACIFIC HEADING FOR WEST COAST. LOOKS PRETTY SHARP
AND WRAPPED UP ALREADY. UNTIL THE SYSTEM GETS BETTER SAMPLED BY ROAB
NETWORK OVR THE CONUS...PROBABLY WILL BE SEEING MODEL SOLUTIONS
SHOWING VARIABILITY WITH TRACK OF THE SYSTEM. IN OTHER WORDS...STAY
TUNED.
VERY QUIET BEYOND EARLY FRIDAY MORNING. BY FRIDAY AFTN...DEEP H85-H7
DRYING EVEN SHOWN BY STRONGER ECMWF...SO SKIES SHOULD BECOME MOSTLY
SUNNY ALL AREAS. HIGH PRESSURE RIDGE FM HUDSON BAY INTO QUEBEC WILL
BE DOMINANT SFC FEATURE THIS WEEKEND. EXPECT MOSTLY CLEAR SKIES WITH
TEMPERATURES STAYING BLO NORMAL NEAR THE LAKES AND POSSIBLY NEAR
NORMAL INLAND TOWARD WI BORDER /NORMAL HIGHS AT WFO MARQUETTE IN UPR
40S/. NIGHTTIME LOWS WILL LIKELY BE BELOW NORMAL WITH SOME NIGHTS IN
THE TEENS POSSIBLE WITH THE HIGH AND DRY AIRMASS OVERHEAD. EXPECT
AFTN HUMIDITY VALUES TO DROP INTO THE 30-35 PCT RANGE THOUGH COULD
EVEN SEE LOWER READINGS WITH DEEPER MIXING. LIGHT WINDS...COOLER
TEMPS...AND RECENT RAINFALL IN SOME AREAS SHOULD KEEP FIRE WX ISSUES
IN CHECK THROUGH THE WEEKEND THOUGH. APPEARS THAT WARMER TEMPS AND
POSSIBLY WINDY CONDITIONS ARE POSSIBLE EARLY TO MID NEXT WEEK...
THOUGH LATEST ECMWF/GFS INDICATE THIS WARM UP WITH BE REPLACED BY
ANOTHER COOL DOWN JUST BEYOND DAY 7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 113 PM EDT TUE APR 17 2012
WITH THE ARRIVAL OF DRIER AIR ASSOCIATED WITH A HIGH PRESSURE RIDGE
BUILDING INTO THE UPPER LAKES AND DAYTIME HEATING AND MIXING...VFR
CONDITIONS WILL CONTINUE AT ALL 3 SITES THROUGH LATE EVENING. AN
INCREASING SOUTH WIND AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM
WILL CAUSE SOME LLWS LATE TONIGHT AT ALL SITES. AS THE LOW CLOSES
IN...CLDS WL THICKEN...AND MVFR CIGS AND VIS WILL SET IN WITH RAIN
LATE TONIGHT INTO WED MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT TUE APR 17 2012
EXPECT LIGHT WINDS INTO TONIGHT WITH HI PRES RIDGE BUILDING INTO THE
AREA. AS A LO PRES SYSTEM APPROACHES TONIGHT AND THE PRES GRADIENT
SHARPENS OVER THE LAKE...S WINDS WILL INCREASE TO AROUND 30 KTS OVER
THE E HALF WED MORNING. IN THE WAKE OF THIS LO PUSHING TO THE E LATE
WED/WED NIGHT...PLAN ON A WSHFT TO THE W WITH WINDS UP TO 25-30 KTS.
THESE STRONGER WINDS WILL DIMINISH AGAIN ON WED NIGHT AS ANOTHER HI
PRES RIDGE BUILDS TOWARD THE UPPER LAKES. DEPENDING ON HOW FAR NORTH
A LOW PRESSURE SYSTEM MOVES...NE WINDS COULD INCREASE TO 25 KTS OVER
SOUTHEAST LAKE SUPERIOR. HI PRES BUILDING INTO THE GREAT LAKES WILL
BRING LIGHTER WINDS FOR THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
725 AM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 443 AM EDT TUE APR 17 2012
00Z RAOBS/LATEST WV IMAGERY AND LATEST RUC ANALYSIS SHOW SHRTWV
RESPONSIBLE FOR WINTRY MIX/GUSTY WINDS YDAY SHEARING ENEWD OVER
ONTARIO ON NW FLANK OF SHARP UPR RDG OFF THE SE COAST. ALTHOUGH
ASSOCIATED SFC LO IS WEAKENING AND MOVING QUICKLY TO THE E THRU
QUEBEC...SOME SHSN ARE FALLING OVER THE NCNTRL AND E AS OF MIDNGT
UNDER THE WEAKENING BUT LINGERING CYC NW FLOW LEFT IN ITS WAKE.
00Z H85 TEMPS AS LO AS -11C PER RUC ANALYSIS AND CONSIDERABLE
LLVL MSTR/INVRN BASE ARND H85 SHOWN ON THE 00Z APX RAOB ARE
CONDITIONS CONDUCIVE FOR THIS BIT OF LATE SEASON LES AND EXTENSIVE
LK SC. UNDER THE H85 THERMAL TROF...SFC TEMPS ARE QUITE CHILLY WITH
TEMPS GENERALLY IN THE 20S. ALTHOUGH PTCHY LO CLDS ARE STILL PRESENT
AS FAR W AS THE MN ARROWHEAD...ANY LINGERING PCPN IS ENDING OVER THE
W WITH APRCH OF TRAILING HI PRES RDG AND VERY DRY AIR SHOWN ON THE
00Z INL RAOB /PWAT 0.13 INCH/. LOOKING FARTHER W...AN UPPER RDG IS
BLDG INTO THE PLAINS WITH 12Z-24Z H3 RISES ARND 150M OVER THE NRN
PLAINS AND S OF NRN BRANCH TROF OVER CENTRAL CANADA. 00Z BISMARCK
RAOB DOES SHOW SOME MSTR THAT SUPPORTED A GOOD AMOUNT OF SC IN THE
NRN PLAINS YDAY. ANOTHER SHRTWV IS MOVING ONSHORE IN THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 443 AM EDT TUE APR 17 2012
MAIN FCST CONCERNS DURING THIS TIME ARE PCPN TRENDS EARLY THIS
MRNG...TEMPS TODAY...AND THEN PCPN CHCS LATE TNGT THRU WED
ASSOCIATED WITH SHRTWV NOW MOVING THRU THE PAC NW.
EARLY THIS MRNG...AS SHRTWV/SFC LO TO THE E CONTINUE TO SLIDE AWAY
AND HI PRES BUILDS INTO THE WRN CWA BY 09Z UNDER STEADY H5
RISES/DNVA THAT IS FCST TO LOWER INVRN BASE TO UNDER 3K FT AT ERY BY
09Z. SO ALTHOUGH QUITE A BIT OF SC WILL LINGER...EXPECT ANY -SHSN TO
BE OVER BY 12Z. LINGERING SC OVER MUCH OF THE CWA WL LIMIT
ADDITIONAL DIURNAL TEMP DROP.
TODAY...WITH HI PRES/DRY AIRMASS PUSHING E ACROSS THE CWA...EXPECT
LAKE EFFECT SC IN THE MRNG TO DISSIPATE IN THE PRESENCE OF DAYTIME
HEATING AND WEAKENING CYC FLOW. BUT WITH HINT OF LINGERING H85
THERMAL TROF AND ARRIVAL OF SOME MSTR SHOWN ON THE 00Z BISMARCK
RAOB...MORE DIURNAL CU/SC SHOULD DVLP OVER MAINLY THE W HALF
INTERIOR INLAND AWAY FM LK BREEZES THAT FORM IN THE RELATIVELY WEAK
PRES GRADIENT. MIXING TO H85-8 ON NAM FCST SDNGS YIELD HI TEMPS
RANGING FM ARND 40 AT ERY TO THE UPR 40S NEAR THE WI BORDER. WITH LK
BREEZE FORMATION...EXPECT COOLER READINGS NEAR THE LK SHORES.
TNGT...LATEST NUMERICAL MODELS IN GOOD AGREEMENT SHOWING SHRTWV NOW
IN THE PAC NW/ACCOMPANYING SFC LO MOVING THRU THE NRN PLAINS AND
INTO NE MN BY 12Z WED...WITH WAD PCPN IN ADVANCE OF THIS FEATURE
OVERSPREADING THE W HALF OF UPR MI BY SUNRISE. MAIN FORCING
MECHANISMS LOOK TO BE VIGOROUS UPR DVGC IN LEFT EXIT OF SUPPORTING
H3 JET MAX/VIGOROUS ISENTROPIC ASCENT POWERED BY H85 SW 50-60KT
WINDS/VIGOROUS H85-7 FGEN IN ADVANCE OF ATTENDANT WARM FNT. OPTED TO
BUMP POPS UP TO CATEGORICAL OVER THE W AFT 06Z GIVEN THESE POTENT
DYNAMICS/IMPRESSIVE DEEP LYR QVECTOR CNVGC/MODEL CONSISTENCY ON
GENERATING PCPN IN THIS AREA. ALTHOUGH FCST H100-85 THKNS AS HI AS
1320-1335M IN ADVANCE OF PCPN ARRIVAL...RAPID ARRIVAL OF WAD
CLD...FASTER ADVECTION OF HIER LLVL SPECIFIC HUMIDITY THAN EARLIER
FCSTS INDICATED...ONSET OF STRONGER WINDS INDICATE PCPN SHOULD BE
ALL RA...INITIAL RELATIVE DRYNESS OF LLVLS THAT LOWERS WBLB TO BLO
32 AT THE SFC SUPPORTS MAINTAING A MENTION OF A BIT OF -FZRA AT THE
ONSET OF THE RA SHIELD OVER THE INTERIOR. ANY ICING WOULD BE
INSIGNIFICANT DUE TO STEADY WARMING SOON AFT PCPN ARRIVAL. UTILIZED
A NON-DIURNAL TEMP CURVE TO HANDLE TEMP TRENDS. TEMPS WL BE LOWEST
AND SINK BLO 32 OVER THE E...BUT PCPN WL NOT GET THERE BEFORE
SUNRISE. ALTHOUGH GFS/NAM SHOW LAPSE RATES NOT MUCH STEEPER THAN
MOIST ADIABATIC/ MUCAPE UNDER 50 J/KG...RETAINED MENTION OF SCHC TS
GIVEN VIGOROUS DYNAMICS/STRONG WARMING AT H85.
WED...SINCE THE SHRTWV/SFC LO AND ACCOMPANYING DYNAMICS ARE FCST TO
MOVE STEADILY EWD...EXPECT THE HIER POPS TO SHIFT W-E THRU THE CWA.
THERE IS AN INDICATION THAT WITH AFTN DRYING/RETURN OF SOME
SUNSHINE...THERE WL BE ENUF DESTABILIZATION TO RESULT IN SOME
SHRA/TS OVER THE INTERIOR W HALF. BUT FCST LARGER SCALE QVECTOR DVGC
IN THE WAKE OF THE DISTURBANCE THAT SHARPENS THE MID LVL INVRN
SHOULD LIMIT THIS CHC. WL RETAIN NO HIER THAN SCHC-CHC POPS OVER THE
INTERIOR FOLLOWING THE DEPARTURE OF THE DEEPER MSTR GIVEN FCST KINX
BLO 20 ON NAM FCST SDNGS.
WED NGT...HI PRES BLDG INTO AREA UNDER DNVA IN THE WAKE OF THE
DEPARTING SHRTWV WL BRING DRY WX TO THE CWA. ALTHOUGH THERE COULD BE
SOME LK CLDS IN THE ABSENCE OF DAYTIME HEATING WITH H85 TEMPS
SINKING AS LO AS -6C...DRYNESS OF THE INCOMING AIRMASS AND LLVL ACYC
FLOW SUGS THIS POTENTIAL IS LO.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 443 AM EDT TUE APR 17 2012
AFTER PASSAGE OF SHORTWAVE TROUGH...UPPER AIR PATTERN FOR THURSDAY
FEATURES INCREASING CONFLUENT FLOW EARLY ON. PRIMARY RESULT IS SFC
RIDGE OVR CNTRL CANADA BUILDING INTO UPPER LAKES REGION THROUGH THE
DAY AS SFC FRONTAL BOUNDARY SETTLES INTO CNTRL GREAT LAKES TO
NORTHERN FRINGE OF OHIO VALLEY. BY THURSDAY AFTN...H85 BAROCLINIC
ZONE FCST TO BE MORE FM NORTHERN IOWA INTO CNTRL LOWER MICHIGAN.
NEXT SHORTWAVE TROUGH ALREADY EMERGING ONTO THE PLAINS BY DAYBREAK
THURSDAY WILL BE QUICKLY HEADING INTO WESTERN GREAT LAKES BY AFTN.
MODELS REMAIN AT ODDS ON HOW FAR NORTH TO BRING SFC-H85 LOW PRESSURE
BY LATE THURSDAY AFTN. OPERATIONAL GFS AND GFS ENSEMBLES KEEP THE
LOW TIED TO SFC FRONT THAT WILL BE OVER SOUTHERN PORTIONS OF GREAT
LAKES AND INTO NORTHERN OHIO VALLEY. GFS HAS SHOWED A MORE SOUTHERN
SUPPRESSED SOLUTION FOR THIS SYSTEM QUITE SOME TIME NOW. OTHER
EXTREME IS ECMWF AND ASSOCIATED ENSEMBLES WHICH RIDE SFC LOW
MORE ALONG H85 THERMAL GRADIENT OVR WI AND LOWER MI. THUS...ECMWF
INSISTS THAT MAJORITY OF CWA EXCEPT FOR PERHAPS FAR NW WOULD BE
IMPACTED BY PRECIPITATION. NAM/UKMET AND THE CANADIAN REPRESENT
MIDDLE GROUND CLIPPING SOUTHERN AND EASTERN CWA WITH PRECIPITATION
BUT OTHERWISE KEEPING CWA DRY.
IT IS BECOMING APPARENT THAT A BIG KEY FOR THIS SYSTEM IS EXTENT OF
DRY AIR THAT LURKS AHEAD OF THE SYSTEM AS LATE AS THURSDAY AFTN.
FCST SOUNDINGS FM GFS/ECMWF AND NAM SHOW POCKET OF DRY AIR LINGERING
BTWN H9 AND H7. NAM IS QUITE EMPHATIC WITH THE DRY AIR SHOWING H85
AT 18Z THURSDAY AOB -20C OVR MUCH OF THE CWA BEFORE ERODING THIS
SOMEWHAT BY 00Z FRIDAY. DRY AIR FLOWING IN ON NORTHEAST SFC WINDS FM
LARGE HIGH PRESSURE OVR NORTHERN ONTARIO AND FACT THAT RIBBON OF
SHARP FRONTOGENEIS IS FCST OVR UPR LAKES SUPPORTS IDEA THAT THERE
COULD BE VERY SHARP CUTOFF TO NORTHERN EXTENT OF PRECIPITATION.
INTERESTING THAT EVEN THE ECMWF SHOWS H85 FGEN AXIS JUST SOUTH OF
CWA WITH H7 FGEN AXIS ROUGHLY FM IMT TO SSM ON THURSDAY NIGHT.
IMAGINE MOST OF THE PRECIPITATION FM THE SYSTEM WILL OCCUR ON THE
SOUTHERN EDGE OF THE H7 FGEN...SO THAT WOULD LEAVE FAR SOUTHEAST CWA
IN LINE TO SEE MOST PRECIPITATION WITH THE SYSTEM. MAJORITY OF THE
PRECIP WOULD PROBABLY FALL THURSDAY NIGHT AS THE LEADOFF FORCING ON
THURSDAY WILL ONLY SERVE TO MOISTEN THE VERY DRY LOW-LEVELS. PREV
FCST MATCHES UP WITH THIS THINKING WELL KEEPING HIGHEST POPS NEAR LK
MICHIGAN ON THURSDAY NIGHT. THIS ALSO MATCHES SURROUNDING WFOS VERY
NICELY.
NOW ON TO PTYPE. LOOKS LIKE SNOW FOR MUCH OF THE EVENT. NORTHEAST
SFC WINDS PROBABLY MITIGATE WARMING EFFECT OFF LK MICHIGAN FOR ALL
BUT SOUTHERN MNM COUNTY. ALSO LARGER SCALE FORCING/INTENSE
PRECIPITATION RATES MOST LIKELY WILL OVERWHELM A MINIMAL NEAR SFC
WARM LAYER. 1000-850MB THICKNESSES AND H85 TEMPS FM ECMWF SUPPORT
MAINLY SNOW BY LATER EVENING INTO THE OVERNIGHT HOURS. WWD GRAPHICS
FM HPC INDICATE SEVERAL INCHES OF SNOW POSSIBLE OVR SOUTH AND EAST
CWA ONCE THE RAIN CHANGES TO SNOW. EVEN THOUGH THIS COULD OCCUR IN
NON-GFS SOLUTIONS...REALLY TOUGH TO GO WITH MORE THAN CHANCY POPS
WITH DOWNPLAYED QPF/SNOW AT THIS POINT GIVEN PERSISTENT GFS SOUTHERN
SOLUTION AND FACT THAT SHARP CUTOFF COULD ULTIMATELY PUSH MOST OF
THE PRECIPITATION TO THE SOUTH OF CWA. SYSTEM IS CURRENTLY CHURNING
ACROSS EASTERN PACIFIC HEADING FOR WEST COAST. LOOKS PRETTY SHARP
AND WRAPPED UP ALREADY. UNTIL THE SYSTEM GETS BETTER SAMPLED BY ROAB
NETWORK OVR THE CONUS...PROBABLY WILL BE SEEING MODEL SOLUTIONS
SHOWING VARIABILITY WITH TRACK OF THE SYSTEM. IN OTHER WORDS...STAY
TUNED.
VERY QUIET BEYOND EARLY FRIDAY MORNING. BY FRIDAY AFTN...DEEP H85-H7
DRYING EVEN SHOWN BY STRONGER ECMWF...SO SKIES SHOULD BECOME MOSTLY
SUNNY ALL AREAS. HIGH PRESSURE RIDGE FM HUDSON BAY INTO QUEBEC WILL
BE DOMINANT SFC FEATURE THIS WEEKEND. EXPECT MOSTLY CLEAR SKIES WITH
TEMPERATURES STAYING BLO NORMAL NEAR THE LAKES AND POSSIBLY NEAR
NORMAL INLAND TOWARD WI BORDER /NORMAL HIGHS AT WFO MARQUETTE IN UPR
40S/. NIGHTTIME LOWS WILL LIKELY BE BELOW NORMAL WITH SOME NIGHTS IN
THE TEENS POSSIBLE WITH THE HIGH AND DRY AIRMASS OVERHEAD. EXPECT
AFTN HUMIDITY VALUES TO DROP INTO THE 30-35 PCT RANGE THOUGH COULD
EVEN SEE LOWER READINGS WITH DEEPER MIXING. LIGHT WINDS...COOLER
TEMPS...AND RECENT RAINFALL IN SOME AREAS SHOULD KEEP FIRE WX ISSUES
IN CHECK THROUGH THE WEEKEND THOUGH. APPEARS THAT WARMER TEMPS AND
POSSIBLY WINDY CONDITIONS ARE POSSIBLE EARLY TO MID NEXT WEEK...
THOUGH LATEST ECMWF/GFS INDICATE THIS WARM UP WITH BE REPLACED BY
ANOTHER COOL DOWN JUST BEYOND DAY 7.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 724 AM EDT TUE APR 17 2012
WITH THE ARRIVAL OF DRIER AIR ASSOCIATED WITH A HI PRES RIDGE
BUILDING INTO THE UPPER LAKES AND DAYTIME HEATING...EXPECT MVFR CIGS
TO GIVE WAY TO VFR CONDITIONS BY LATE MORNING AT ALL 3 SITES. THEN
VFR CONDITIONS AND RELATIVELY LIGHT WINDS WILL PREVAIL THRU THIS
EVNG BEFORE AN INCRSG S WIND AHEAD OF AN APPROACHING LO PRES SYSTEM
CAUSES SOME LLWS OVERNGT. AS THE LO CLOSES IN...CLDS WL THICKEN...
BUT CONDITIONS SHOULD REMAIN VFR THRU 12Z EXPECT PERHAPS AT IWD...
WHICH WL BE CLOSER TO THE INCOMING LO.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT TUE APR 17 2012
EXPECT LIGHT WINDS INTO TONIGHT WITH HI PRES RIDGE BUILDING INTO THE
AREA. AS A LO PRES SYSTEM APPROACHES TONIGHT AND THE PRES GRADIENT
SHARPENS OVER THE LAKE...S WINDS WILL INCREASE TO AROUND 30 KTS OVER
THE E HALF WED MORNING. IN THE WAKE OF THIS LO PUSHING TO THE E LATE
WED/WED NIGHT...PLAN ON A WSHFT TO THE W WITH WINDS UP TO 25-30 KTS.
THESE STRONGER WINDS WILL DIMINISH AGAIN ON WED NIGHT AS ANOTHER HI
PRES RIDGE BUILDS TOWARD THE UPPER LAKES. DEPENDING ON HOW FAR NORTH
A LOW PRESSURE SYSTEM MOVES...NE WINDS COULD INCREASE TO 25 KTS OVER
SOUTHEAST LAKE SUPERIOR. HI PRES BUILDING INTO THE GREAT LAKES WILL
BRING LIGHTER WINDS FOR THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
447 AM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 443 AM EDT TUE APR 17 2012
00Z RAOBS/LATEST WV IMAGERY AND LATEST RUC ANALYSIS SHOW SHRTWV
RESPONSIBLE FOR WINTRY MIX/GUSTY WINDS YDAY SHEARING ENEWD OVER
ONTARIO ON NW FLANK OF SHARP UPR RDG OFF THE SE COAST. ALTHOUGH
ASSOCIATED SFC LO IS WEAKENING AND MOVING QUICKLY TO THE E THRU
QUEBEC...SOME SHSN ARE FALLING OVER THE NCNTRL AND E AS OF MIDNGT
UNDER THE WEAKENING BUT LINGERING CYC NW FLOW LEFT IN ITS WAKE.
00Z H85 TEMPS AS LO AS -11C PER RUC ANALYSIS AND CONSIDERABLE
LLVL MSTR/INVRN BASE ARND H85 SHOWN ON THE 00Z APX RAOB ARE
CONDITIONS CONDUCIVE FOR THIS BIT OF LATE SEASON LES AND EXTENSIVE
LK SC. UNDER THE H85 THERMAL TROF...SFC TEMPS ARE QUITE CHILLY WITH
TEMPS GENERALLY IN THE 20S. ALTHOUGH PTCHY LO CLDS ARE STILL PRESENT
AS FAR W AS THE MN ARROWHEAD...ANY LINGERING PCPN IS ENDING OVER THE
W WITH APRCH OF TRAILING HI PRES RDG AND VERY DRY AIR SHOWN ON THE
00Z INL RAOB /PWAT 0.13 INCH/. LOOKING FARTHER W...AN UPPER RDG IS
BLDG INTO THE PLAINS WITH 12Z-24Z H3 RISES ARND 150M OVER THE NRN
PLAINS AND S OF NRN BRANCH TROF OVER CENTRAL CANADA. 00Z BISMARCK
RAOB DOES SHOW SOME MSTR THAT SUPPORTED A GOOD AMOUNT OF SC IN THE
NRN PLAINS YDAY. ANOTHER SHRTWV IS MOVING ONSHORE IN THE PAC NW.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 443 AM EDT TUE APR 17 2012
MAIN FCST CONCERNS DURING THIS TIME ARE PCPN TRENDS EARLY THIS
MRNG...TEMPS TODAY...AND THEN PCPN CHCS LATE TNGT THRU WED
ASSOCIATED WITH SHRTWV NOW MOVING THRU THE PAC NW.
EARLY THIS MRNG...AS SHRTWV/SFC LO TO THE E CONTINUE TO SLIDE AWAY
AND HI PRES BUILDS INTO THE WRN CWA BY 09Z UNDER STEADY H5
RISES/DNVA THAT IS FCST TO LOWER INVRN BASE TO UNDER 3K FT AT ERY BY
09Z. SO ALTHOUGH QUITE A BIT OF SC WILL LINGER...EXPECT ANY -SHSN TO
BE OVER BY 12Z. LINGERING SC OVER MUCH OF THE CWA WL LIMIT
ADDITIONAL DIURNAL TEMP DROP.
TODAY...WITH HI PRES/DRY AIRMASS PUSHING E ACROSS THE CWA...EXPECT
LAKE EFFECT SC IN THE MRNG TO DISSIPATE IN THE PRESENCE OF DAYTIME
HEATING AND WEAKENING CYC FLOW. BUT WITH HINT OF LINGERING H85
THERMAL TROF AND ARRIVAL OF SOME MSTR SHOWN ON THE 00Z BISMARCK
RAOB...MORE DIURNAL CU/SC SHOULD DVLP OVER MAINLY THE W HALF
INTERIOR INLAND AWAY FM LK BREEZES THAT FORM IN THE RELATIVELY WEAK
PRES GRADIENT. MIXING TO H85-8 ON NAM FCST SDNGS YIELD HI TEMPS
RANGING FM ARND 40 AT ERY TO THE UPR 40S NEAR THE WI BORDER. WITH LK
BREEZE FORMATION...EXPECT COOLER READINGS NEAR THE LK SHORES.
TNGT...LATEST NUMERICAL MODELS IN GOOD AGREEMENT SHOWING SHRTWV NOW
IN THE PAC NW/ACCOMPANYING SFC LO MOVING THRU THE NRN PLAINS AND
INTO NE MN BY 12Z WED...WITH WAD PCPN IN ADVANCE OF THIS FEATURE
OVERSPREADING THE W HALF OF UPR MI BY SUNRISE. MAIN FORCING
MECHANISMS LOOK TO BE VIGOROUS UPR DVGC IN LEFT EXIT OF SUPPORTING
H3 JET MAX/VIGOROUS ISENTROPIC ASCENT POWERED BY H85 SW 50-60KT
WINDS/VIGOROUS H85-7 FGEN IN ADVANCE OF ATTENDANT WARM FNT. OPTED TO
BUMP POPS UP TO CATEGORICAL OVER THE W AFT 06Z GIVEN THESE POTENT
DYNAMICS/IMPRESSIVE DEEP LYR QVECTOR CNVGC/MODEL CONSISTENCY ON
GENERATING PCPN IN THIS AREA. ALTHOUGH FCST H100-85 THKNS AS HI AS
1320-1335M IN ADVANCE OF PCPN ARRIVAL...RAPID ARRIVAL OF WAD
CLD...FASTER ADVECTION OF HIER LLVL SPECIFIC HUMIDITY THAN EARLIER
FCSTS INDICATED...ONSET OF STRONGER WINDS INDICATE PCPN SHOULD BE
ALL RA...INITIAL RELATIVE DRYNESS OF LLVLS THAT LOWERS WBLB TO BLO
32 AT THE SFC SUPPORTS MAINTAING A MENTION OF A BIT OF -FZRA AT THE
ONSET OF THE RA SHIELD OVER THE INTERIOR. ANY ICING WOULD BE
INSIGNIFICANT DUE TO STEADY WARMING SOON AFT PCPN ARRIVAL. UTILIZED
A NON-DIURNAL TEMP CURVE TO HANDLE TEMP TRENDS. TEMPS WL BE LOWEST
AND SINK BLO 32 OVER THE E...BUT PCPN WL NOT GET THERE BEFORE
SUNRISE. ALTHOUGH GFS/NAM SHOW LAPSE RATES NOT MUCH STEEPER THAN
MOIST ADIABATIC/ MUCAPE UNDER 50 J/KG...RETAINED MENTION OF SCHC TS
GIVEN VIGOROUS DYNAMICS/STRONG WARMING AT H85.
WED...SINCE THE SHRTWV/SFC LO AND ACCOMPANYING DYNAMICS ARE FCST TO
MOVE STEADILY EWD...EXPECT THE HIER POPS TO SHIFT W-E THRU THE CWA.
THERE IS AN INDICATION THAT WITH AFTN DRYING/RETURN OF SOME
SUNSHINE...THERE WL BE ENUF DESTABILIZATION TO RESULT IN SOME
SHRA/TS OVER THE INTERIOR W HALF. BUT FCST LARGER SCALE QVECTOR DVGC
IN THE WAKE OF THE DISTURBANCE THAT SHARPENS THE MID LVL INVRN
SHOULD LIMIT THIS CHC. WL RETAIN NO HIER THAN SCHC-CHC POPS OVER THE
INTERIOR FOLLOWING THE DEPARTURE OF THE DEEPER MSTR GIVEN FCST KINX
BLO 20 ON NAM FCST SDNGS.
WED NGT...HI PRES BLDG INTO AREA UNDER DNVA IN THE WAKE OF THE
DEPARTING SHRTWV WL BRING DRY WX TO THE CWA. ALTHOUGH THERE COULD BE
SOME LK CLDS IN THE ABSENCE OF DAYTIME HEATING WITH H85 TEMPS
SINKING AS LO AS -6C...DRYNESS OF THE INCOMING AIRMASS AND LLVL ACYC
FLOW SUGS THIS POTENTIAL IS LO.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 443 AM EDT TUE APR 17 2012
AFTER PASSAGE OF SHORTWAVE TROUGH...UPPER AIR PATTERN FOR THURSDAY
FEATURES INCREASING CONFLUENT FLOW EARLY ON. PRIMARY RESULT IS SFC
RIDGE OVR CNTRL CANADA BUILDING INTO UPPER LAKES REGION THROUGH THE
DAY AS SFC FRONTAL BOUNDARY SETTLES INTO CNTRL GREAT LAKES TO
NORTHERN FRINGE OF OHIO VALLEY. BY THURSDAY AFTN...H85 BAROCLINIC
ZONE FCST TO BE MORE FM NORTHERN IOWA INTO CNTRL LOWER MICHIGAN.
NEXT SHORTWAVE TROUGH ALREADY EMERGING ONTO THE PLAINS BY DAYBREAK
THURSDAY WILL BE QUICKLY HEADING INTO WESTERN GREAT LAKES BY AFTN.
MODELS REMAIN AT ODDS ON HOW FAR NORTH TO BRING SFC-H85 LOW PRESSURE
BY LATE THURSDAY AFTN. OPERATIONAL GFS AND GFS ENSEMBLES KEEP THE
LOW TIED TO SFC FRONT THAT WILL BE OVER SOUTHERN PORTIONS OF GREAT
LAKES AND INTO NORTHERN OHIO VALLEY. GFS HAS SHOWED A MORE SOUTHERN
SUPPRESSED SOLUTION FOR THIS SYSTEM QUITE SOME TIME NOW. OTHER
EXTREME IS ECMWF AND ASSOCIATED ENSEMBLES WHICH RIDE SFC LOW
MORE ALONG H85 THERMAL GRADIENT OVR WI AND LOWER MI. THUS...ECMWF
INSISTS THAT MAJORITY OF CWA EXCEPT FOR PERHAPS FAR NW WOULD BE
IMPACTED BY PRECIPITATION. NAM/UKMET AND THE CANADIAN REPRESENT
MIDDLE GROUND CLIPPING SOUTHERN AND EASTERN CWA WITH PRECIPITATION
BUT OTHERWISE KEEPING CWA DRY.
IT IS BECOMING APPARENT THAT A BIG KEY FOR THIS SYSTEM IS EXTENT OF
DRY AIR THAT LURKS AHEAD OF THE SYSTEM AS LATE AS THURSDAY AFTN.
FCST SOUNDINGS FM GFS/ECMWF AND NAM SHOW POCKET OF DRY AIR LINGERING
BTWN H9 AND H7. NAM IS QUITE EMPHATIC WITH THE DRY AIR SHOWING H85
AT 18Z THURSDAY AOB -20C OVR MUCH OF THE CWA BEFORE ERODING THIS
SOMEWHAT BY 00Z FRIDAY. DRY AIR FLOWING IN ON NORTHEAST SFC WINDS FM
LARGE HIGH PRESSURE OVR NORTHERN ONTARIO AND FACT THAT RIBBON OF
SHARP FRONTOGENEIS IS FCST OVR UPR LAKES SUPPORTS IDEA THAT THERE
COULD BE VERY SHARP CUTOFF TO NORTHERN EXTENT OF PRECIPITATION.
INTERESTING THAT EVEN THE ECMWF SHOWS H85 FGEN AXIS JUST SOUTH OF
CWA WITH H7 FGEN AXIS ROUGHLY FM IMT TO SSM ON THURSDAY NIGHT.
IMAGINE MOST OF THE PRECIPITATION FM THE SYSTEM WILL OCCUR ON THE
SOUTHERN EDGE OF THE H7 FGEN...SO THAT WOULD LEAVE FAR SOUTHEAST CWA
IN LINE TO SEE MOST PRECIPITATION WITH THE SYSTEM. MAJORITY OF THE
PRECIP WOULD PROBABLY FALL THURSDAY NIGHT AS THE LEADOFF FORCING ON
THURSDAY WILL ONLY SERVE TO MOISTEN THE VERY DRY LOW-LEVELS. PREV
FCST MATCHES UP WITH THIS THINKING WELL KEEPING HIGHEST POPS NEAR LK
MICHIGAN ON THURSDAY NIGHT. THIS ALSO MATCHES SURROUNDING WFOS VERY
NICELY.
NOW ON TO PTYPE. LOOKS LIKE SNOW FOR MUCH OF THE EVENT. NORTHEAST
SFC WINDS PROBABLY MITIGATE WARMING EFFECT OFF LK MICHIGAN FOR ALL
BUT SOUTHERN MNM COUNTY. ALSO LARGER SCALE FORCING/INTENSE
PRECIPITATION RATES MOST LIKELY WILL OVERWHELM A MINIMAL NEAR SFC
WARM LAYER. 1000-850MB THICKNESSES AND H85 TEMPS FM ECMWF SUPPORT
MAINLY SNOW BY LATER EVENING INTO THE OVERNIGHT HOURS. WWD GRAPHICS
FM HPC INDICATE SEVERAL INCHES OF SNOW POSSIBLE OVR SOUTH AND EAST
CWA ONCE THE RAIN CHANGES TO SNOW. EVEN THOUGH THIS COULD OCCUR IN
NON-GFS SOLUTIONS...REALLY TOUGH TO GO WITH MORE THAN CHANCY POPS
WITH DOWNPLAYED QPF/SNOW AT THIS POINT GIVEN PERSISTENT GFS SOUTHERN
SOLUTION AND FACT THAT SHARP CUTOFF COULD ULTIMATELY PUSH MOST OF
THE PRECIPITATION TO THE SOUTH OF CWA. SYSTEM IS CURRENTLY CHURNING
ACROSS EASTERN PACIFIC HEADING FOR WEST COAST. LOOKS PRETTY SHARP
AND WRAPPED UP ALREADY. UNTIL THE SYSTEM GETS BETTER SAMPLED BY ROAB
NETWORK OVR THE CONUS...PROBABLY WILL BE SEEING MODEL SOLUTIONS
SHOWING VARIABILITY WITH TRACK OF THE SYSTEM. IN OTHER WORDS...STAY
TUNED.
VERY QUIET BEYOND EARLY FRIDAY MORNING. BY FRIDAY AFTN...DEEP H85-H7
DRYING EVEN SHOWN BY STRONGER ECMWF...SO SKIES SHOULD BECOME MOSTLY
SUNNY ALL AREAS. HIGH PRESSURE RIDGE FM HUDSON BAY INTO QUEBEC WILL
BE DOMINANT SFC FEATURE THIS WEEKEND. EXPECT MOSTLY CLEAR SKIES WITH
TEMPERATURES STAYING BLO NORMAL NEAR THE LAKES AND POSSIBLY NEAR
NORMAL INLAND TOWARD WI BORDER /NORMAL HIGHS AT WFO MARQUETTE IN UPR
40S/. NIGHTTIME LOWS WILL LIKELY BE BELOW NORMAL WITH SOME NIGHTS IN
THE TEENS POSSIBLE WITH THE HIGH AND DRY AIRMASS OVERHEAD. EXPECT
AFTN HUMIDITY VALUES TO DROP INTO THE 30-35 PCT RANGE THOUGH COULD
EVEN SEE LOWER READINGS WITH DEEPER MIXING. LIGHT WINDS...COOLER
TEMPS...AND RECENT RAINFALL IN SOME AREAS SHOULD KEEP FIRE WX ISSUES
IN CHECK THROUGH THE WEEKEND THOUGH. APPEARS THAT WARMER TEMPS AND
POSSIBLY WINDY CONDITIONS ARE POSSIBLE EARLY TO MID NEXT WEEK...
THOUGH LATEST ECMWF/GFS INDICATE THIS WARM UP WITH BE REPLACED BY
ANOTHER COOL DOWN JUST BEYOND DAY 7.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 124 AM EDT TUE APR 17 2012
LIGHT SNOW SHOWERS WILL BE ENDING OVERNIGHT AT KCMX AND KSAW AS RDG
BUILDS IN FM WEST. MVFR CLOUD DECK SHOULD SCT OUT AT KIWD AROUND 09Z
AS WINDS SHIFT TO THE SE. WITH WEAKENING NW FLOW AT KCMX AND KSAW IT
WILL TAKE A BIT LONGER FOR CLRG TO REACH THERE (AROUND 12Z). 850 MB
COLD POOL AT LEAST INITIALLY MAY KEEP SOME SCT CUMULUS AROUND
THROUGH AT LEAST THE MORNING HRS ON TUE. ERLY LAKE BREEZE SHOULD
KICK IN AT KCMX BY MIDDAY. EXPECT INCREASING MID-HIGH CLOUDS TUE
EVENING AHEAD OF APPROACHING SYSTEM OVER THE PLAINS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 AM EDT TUE APR 17 2012
EXPECT LIGHT WINDS INTO TONIGHT WITH HI PRES RIDGE BUILDING INTO THE
AREA. AS A LO PRES SYSTEM APPROACHES TONIGHT AND THE PRES GRADIENT
SHARPENS OVER THE LAKE...S WINDS WILL INCREASE TO AROUND 30 KTS OVER
THE E HALF WED MORNING. IN THE WAKE OF THIS LO PUSHING TO THE E LATE
WED/WED NIGHT...PLAN ON A WSHFT TO THE W WITH WINDS UP TO 25-30 KTS.
THESE STRONGER WINDS WILL DIMINISH AGAIN ON WED NIGHT AS ANOTHER HI
PRES RIDGE BUILDS TOWARD THE UPPER LAKES. DEPENDING ON HOW FAR NORTH
A LOW PRESSURE SYSTEM MOVES...NE WINDS COULD INCREASE TO 25 KTS OVER
SOUTHEAST LAKE SUPERIOR. HI PRES BUILDING INTO THE GREAT LAKES WILL
BRING LIGHTER WINDS FOR THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
144 AM EDT TUE APR 17 2012
.SYNOPSIS...
ISSUED AT 408 PM EDT MON APR 16 2012
WINDY CONDITIONS WILL CONTINUE INTO THE EVENING HOURS BEFORE
SUBSIDING AFTER DARK. HIGH WINDS CAN BE EXPECTED THROUGH 800 PM OR
SO. SCATTERED RAIN SHOWERS THIS EVENING WILL MIX WITH SOME SNOW
BEFORE ENDING TOWARDS MIDNIGHT. OVERNIGHT CLOUDS WILL DECREASE AS
WILL THE WINDS SETTING THE STAGE FOR ANOTHER ROUND OF FROST AND
FREEZING TEMPERATURES LATE. A DRY AND COOL DAY IS EXPECTED ON
TUESDAY...BEFORE RAIN RETURNS TO THE FORECAST FOR
WEDNESDAY...THURSDAY AND FRIDAY. THE RAIN WILL BE ASSOCIATED WITH
A FRONTAL BOUNDARY THAT LINGERS IN THE REGION.
&&
.UPDATE...
ISSUED AT 906 PM EDT MON APR 16 2012
WE WENT AHEAD AND CANCELLED THE WIND ADVISORY EARLY AS WINDS HAVE
DIMINISHED WELL BELOW ADVISORY CRITERIA AS THE GRADIENT WEAKENS
AND DIURNAL MIXING IS LOST. THE FROST ADVISORY/FREEZE WARNING
REMAINS AS IS WITH NO CHANGES NEEDED THERE.
WE ALSO PULLED MOST OF THE PCPN FOR THE EVENING HOURS. REGIONAL
RADAR IMAGERY AND SFC OBSERVATIONS INDICATE THAT ALMOST ALL PCPN
IS NORTH OF THE CWFA. A FEW SPRINKLES/FLURRIES WILL BE POSSIBLE
THROUGH 10 PM THIS EVENING NORTH OF U.S.-10...HOWEVER THAT WILL BE
INSIGNIFICANT. WE WILL SEE A CLEARING TREND AS THE UPPER LOW PULLS AWAY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 408 PM EDT MON APR 16 2012
MAIN CONCERNS IN THE SHORT TERM PERTAIN TO HEADLINES. NAMELY...THE
WIND ADVISORY THAT IS OUT THROUGH 1000PM AND FROST AND FREEZE
HEADLINES.
REGARDING THE WIND ADVISORY...MAINTAINED IT AS IS...COVERING THE
ENTIRE FORECAST AREA THROUGH 1000PM. LATEST HRRR MODEL CONTINUES
TO INDICATE THE EXPIRATION TIME LOOKS GOOD. STRONG WINDS CONTINUE
THROUGH 800 PM OR SO...THEN DIMINISH STEADILY THEREAFTER. SOLID
PUSH OF COLD AIR ADVECTION IS NOW COMING ACROSS THE LAKE AND
EXPECT STRONG WINDS IN THE COLD AIR ADVECTION TO CONTINUE. GUSTS
OF 45 TO 55 MPH SHOULD CONTINUE THROUGH SUNSET.
WILL BE ISSUING A FREEZE WARNING FOR THE NORTHERN HALF OF THE
FORECAST AREA...MUSKEGON...NEWAYGO...MONTCALM AND CLINTON COUNTIES
NORTHWARD. A FROST ADVISORY FOR OTTAWA...KENT...IONIA AND INGHAM
COUNTIES SOUTHWARD. CLOUDS WILL SCATTER OUT OVERNIGHT AND WINDS
WILL DIMINISH CONSIDERABLY AFTER 06Z. THE COLD AIR ADVECTION ONLY
WILL DRIVE TEMPERATURES TO LEVELS THAT WILL BE A CONCERN TO TENDER
VEGETATION. EXPECTING UPPER 20S FOR LOWS TO THE NORTH AND LOWER
30S TO THE SOUTH.
OTHERWISE...QUIET WEATHER ON TUESDAY WITH SURFACE RIDGING SLIDING
ACROSS THE LOWER PENINSULA. INCREASING CLOUDS ARE EXPECTED TUESDAY
NIGHT AHEAD OF A SHORTWAVE SLIDING EAST IN ZONAL FLOW. KEPT THE
FORECAST DRY AS THE PRECIP SHOULD HOLD OFF INTO WEDNESDAY. ANOTHER
FROST/FREEZE POTENTIAL TUESDAY NIGHT...BUT AN INCREASE WIND AND
CLOUD COVER MAY END THE THREAT. LATER FORECASTS WILL LOOK INTO
THIS THREAT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 PM EDT MON APR 16 2012
PROGRESSIVE FLOW WILL BRING ANOTHER NORTHERN STREAM WAVE INTO THE
REGION WED/WED NIGHT. MODEL TRENDS ARE A BIT FASTER...SO HAVE ADDED
POPS TO THE EASTERN CWA LATE WED...THEN REMOVED POPS FOR LATE WED
NIGHT IN THE NW CWA. COULD BE A FEW ISOLATED THUNDERSTORMS WITH
SOME WEAK INSTABILITY.
THE FRONT STALLS JUST TO OUR SOUTH WITH A WAVE OF LOW PRESSURE
TRACKING ALONG IT. THE MODELS ARE TRENDING FURTHER NORTH WITH THIS
LOW...THE GFS COMING MORE IN LINE WITH THE EURO. SO THE SHOWERS
SHOULD RETURN/LINGER INTO THURSDAY/THURSDAY NIGHT. COLD ENOUGH AIR
MAY FILTER IN BEHIND THE LOW...WHERE RAIN COULD MIX WITH SOME SNOW
LATE FRIDAY INTO FRIDAY NIGHT. BUT BY THIS TIME FRAME THE PCPN
SHOULD BE RATHER LIGHT.
THE WEEKEND CONTINUES TO LOOK DRY BUT COOL AS THE PATTERN BECOMES
BLOCKED. THE LOW TO OUR EAST STALLS AND MAY EVEN RETROGRADE A BIT
INTO THE FIRST PART OF NEXT WEEK. HAVE PUT LOW POPS IN FOR THE FAR
SE CWA FOR MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 143 AM EDT TUE APR 17 2012
FORECAST CONCERNS TO AVIATION INTERESTS ARE MINIMAL FOR THIS SET
OF FCSTS. SKIES HAVE GENERALLY CLEARED OUT ACROSS THE
AREA...EXCEPT FOR A PATCH OF CLOUDS BASED AROUND 4K FEET NEAR
KGRR. THIS WILL REMAIN AROUND FOR THE NEXT FEW HOURS...BUT THEN
SKIES SHOULD GENERALLY GO CLEAR ONCE AGAIN AND REMAIN THAT WAY
THROUGH TUE. W/NW WINDS WILL REMAIN UP AROUND 5 TO 10 KNOTS THROUGH
THE NIGHT. GRADIENT WILL WEAKEN THROUGH TUE...BUT DIURNAL MIXING
WILL KEEP WIND SPEEDS STEADY. HIGH PRESSURE WILL MOVE OVERHEAD TUE
NIGHT...ALLOWING WINDS TO GO LIGHT AND VARIABLE.
&&
.MARINE...
ISSUED AT 906 PM EDT MON APR 16 2012
WE WENT AHEAD AND DOWNGRADED THE GALE WARNING TO A SMALL CRAFT
ADVISORY AS WINDS HAVE COME DOWN BELOW CRITERIA ALL ALONG THE
COAST. WINDS ARE RIGHT AROUND SMALL CRAFT ADVISORY
CRITERIA...HOWEVER THE WAVES ARE STILL ABOVE THE FOUR FOOT
CRITERIA PER THE MID LAKE BUOY. THE WAVE MODEL INDICATES THAT WE
MAY SEE FOUR FOOTERS REMAIN POSSIBLE INTO THE OVERNIGHT HOURS
BEFORE SUBSIDING. WE RAN THE ADVISORY OUT THROUGH 09Z...AND THIS
SHOULD BE ABLE TO EXPIRE ON TIME WITH THE MORNING FCST PACKAGE.
&&
.HYDROLOGY...
ISSUED AT 408 PM EDT MON APR 16 2012
RAINFALL OVER THE WEEKEND REACHED THE 1.00 TO 2.00 INCH RANGE IN
MANY LOCATIONS. THE HIGHEST TOTAL OCCURRED AT THE SOUTH HAVEN
WATER INTAKE PLANT WHERE 3.02 INCHES OF RAIN WAS MEASURED. THE
HEAVIEST RAINS WERE NOTED ACROSS THE WEST AND SOUTHWEST PORTIONS
OF THE FORECAST AFFECTING THE KALAMAZOO AND ST. JOSEPH RIVER
BASINS THE MOST. AT THIS POINT...RIVERS ARE SHOWING WITHIN BANK
RISES...BUT NO ADVISORIES AND WARNINGS HAVE BEEN ISSUED.
NOT EXPECTING MUCH IN THE WAY OF ADVISORIES OR WARNINGS BASED ON
HOW THE RAIN FELL. IN ADDITION WE ARE LOOKING AT MAINLY DRY
WEATHER THROUGH TUESDAY NIGHT. RAINFALL WITH A FRONT ON WEDNESDAY
SHOULD BE FAIRLY LIGHT AS WELL. RIVERS SHOULD BE ABLE TO STAY
WITHIN BANK OR RECEDE THROUGH MID WEEK AT MOST LOCATIONS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MIZ056>059-
064>067-071>074.
FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MIZ037>040-
043>046-050>052.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
LMZ844>849.
&&
$$
UPDATE...NJJ
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...JK
AVIATION...NJJ
HYDROLOGY...DUKE
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS JACKSON MS
351 PM CDT TUE APR 17 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT...LARGE RAIN SHIELD
OVERSPREADING THE REGION AS ABUNDANT MOISTURE IS IN PLACE. BLENDED
TOTAL PRECIPITABLE WATER SATELLITE IMAGERY INDICATES 1-1.5 INCHES
ACROSS MAINLY LOCATIONS ALONG AND SOUTH OF I-20. THIS IS GENERALLY
120-180 PERCENT OF NORMAL. THIS HAS LED TO SEVERAL FLASH FLOOD
WARNINGS ACROSS THE REGION. STORM TOTAL PRECIP SINCE YESTERDAY
MORNING INDICATES THAT MANY LOCATIONS GENERALLY ALONG AND WEST OF
I-55 SHOWS RAINFALL TOTALS AROUND 3-5 INCHES. THIS ACTIVITY COMES AS
A SHORTWAVE TROUGH SLOWLY MOVES INTO THE REGION. WHILE THE PRIMARY
CONCERN IS THE FLOODING ACROSS THE REGION...SOME BETTER CONVECTIVE
CELLS HAVE EXHIBITED SOME STRONG TO SEVERE TENDENCY...ESPECIALLY
THOSE THAT ARE ENTERING A REGION THAT HAS BEEN ABLE TO WARM
UP/DESTABILIZE BETTER TODAY. EXTENSIVE CLOUD COVER AND CONTINUOUS
RAIN HAS KEPT TEMPERATURES IN THE UPPER 50S AND LOWER 60S FOR MUCH
OF THE DAY. THE FAR SOUTHEAST AND EAST HAVE BEEN ABLE TO WARM MORE
WITH LATER ONSET OF CLOUD COVER AND RAIN. THESE LOCATIONS HAVE
GOTTEN INTO THE MID TO UPPER 60S AND LOWER 70S. IT IS IN THESE AREAS
WHERE RUC ANALYSIS SHOWS SLIGHT BETTER SFC CAPE(CLOSE TO 1000 J/KG).
WHILE LOW LEVEL SHEAR IS ON THE LOW SIDE...DEEPER LAYER SHEAR IS
ABOUT 30-40KTS. THE MAIN CONCERN WITH THESE WOULD BE WIND GUSTS AS
MID LEVEL TEMPS ARE NOT TOO COLD WITH VALUES AROUND -11 TO -13C TO
SUPPORT MUCH HAIL...BUT IF ANY IT WILL BE ON THE SMALL SIDE.
AS THE SHORTWAVE TROUGH CONTINUES TO MOVE ACROSS THE REGION THIS
AFTERNOON AND THIS EVENING...THE AXIS OF RAIN WILL CONTINUE TO SHIFT
TO THE EAST. GRADUAL CLEARING WILL TAKE PLACE FROM WEST TO EAST
THROUGH THE EVENING INTO TONIGHT WITH DRIER AIR FILTERING IN BEHIND
IT ALONG WITH HIGH PRESSURE AT THE SFC. WITH THE CLEARING
SKIES...RELATIVELY LIGHT WINDS AND SATURATED SOILS...PATCHY FOG COULD
DEVELOP TONIGHT AFTER MIDNIGHT. THIS WOULD MAINLY BE FOR LOCATIONS
ALONG AND NORTHWEST OF THE NATCHEZ TRACE. DECENTLY HIGH SREF PROBS
ALSO INDICATE THIS PROBABILITY AND HAVE INCLUDED IN THE FORECAST. BY
12Z WEDNESDAY...MODEL PW VALUES ARE 0.45 INCHES ACROSS THE
DELTA...0.70 INCHES ACROSS THE JACKSON AREA AND JUST UNDER AN INCH IN
THE PINE BELT. THIS WILL ALLOW FOR A RATHER PLEASANT DAY WEDNESDAY.
SUNNY SKIES...A GOOD NORTH WIND AND DRIER AIR WILL BE IN PLACE.
TEMPERATURES WILL START OUT CHILLY IN THE MORNING WITH READINGS IN
THE UPPER 40S IN THE DELTA...TO THE MID/UPPER 50S IN THE PINE
BELT(WHERE CLOUDS AND RAIN WILL BE SLOWER TO DEPART OVERNIGHT).
AFTERNOON HIGHS WILL REACH INTO THE MID 70S WEDNESDAY.
SFC HIGH PRESSURE CENTERED ACROSS THE MID-ATLANTIC STATES CONTINUES
TO BE BETTER ESTABLISHED ACROSS THE AREA THROUGH THURSDAY WITH
GENERALLY ZONAL FLOW ALOFT. THIS WILL LEAD TO DRY
CONDITIONS...MOSTLY SUNNY SKIES...COOL OVERNIGHT LOWS DUE TO GOOD
RADIATIONAL COOLING CONDITIONS AND COOLER AFTERNOON HIGHS. BY THURSDAY
NIGHT...THE SFC HIGH WILL BE SHIFTING FURTHER EAST...BRINGING THE
REGION UNDER THE WESTERN PERIPHERY AND SOUTHERLY WINDS WILL RETURN.
MOISTURE WILL INCREASE AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM
LOCATED ACROSS THE TEXAS PANHANDLE/RED RIVER VALLEY AT 12Z FRIDAY.
WITH THE INCREASE IN MOISTURE...OVERNIGHT LOWS ON THURSDAY WILL BE
HIGHER AND INTO THE LOWER 50S. /28/
.LONG TERM...FRIDAY THROUGH TUESDAY...MAIN FOCUS IN THE MEDIUM RANGE
WILL BE ON A DIGGING SHORTWAVE INTO THE DEEP SOUTH THAT BOTH GFS AND
ECMWF MODELS NOW ARE CLOSING OFF A 500MB(560DM) LOW CENTER NEAR THE MS
COAST FOR SATURDAY NIGHT AND THEN MOVING IT SLOWLY EWD. MEANWHILE...A
FLAT MID LEVEL RIDGE ALOFT SHOULD HOLD A DRY WNW ZONAL FLOW IN PLACE
THURSDAY THAT BACKS WITH WEAK LOW LEVEL WARM ADVECTION DEVELOPING
THURSDAY NIGHT AND FRIDAY. EXPECT LOW LEVEL FRONTOGENESIS FROM THE MID
SOUTH TO THE ARKLATEX FRIDAY NIGHT WITH INCREASING RAIN/TSRA CHANCES
FOR OUR AREA FRIDAY AFTERNOON RIGHT THROUGH SATURDAY EVENING.
THE SLOWER PROGRESSION OF THIS SYSTEM WILL RESULT IN HIGHER QPF
AMOUNTS THAT WOULD NOW APPEAR TO BE AROUND 2 INCHES WITH LOCALLY
HIGHER 3 TO 4 INCHES POSSIBLE IN SERN MS BY EARLY SUNDAY. A WIDER
RIBBON OF 1.4 INCH PWATS AND 7-500MB LAPSE RATES OF 6.5C SUPPORT
SCATTERED TSRA ALONG THE SLOWING FRONT FRIDAY NIGHT WITH SURFACE
CYCLOGENESIS(1003MB) IN THE KMSY VICINITY EARLY SATURDAY. THE FRONT
PLODS EWD INTO THE I-59 CORRIDOR LATER ON SATURDAY WITH AN UPPER
DEFORMATION ZONE LOCKING IN THE WRAP AROUND MOISTURE BEING FORCED
NWWD ON STRENGTHENING ELY LOW LEVEL FLOW THROUGH THE GULF STATES. WE
COULD BE IN FOR A REAL SOAKER AS PATTERN TAKING ON MORE OF AN EL NINO
LOOK LATELY.
WE FINALLY BEGIN DRYING OUT EARLY SUNDAY FOLLOWED BY A NOTICEABLY
COOLER AIRMASS FOR THE START OF NEXT WEEK AS OVERNIGHT LOWS LIKELY TO
DIP INTO THE 40S EARLY SUNDAY AND MONDAY MORNINGS. OUR HIGHS STAY
WELL BELOW NORMAL IN THE 65-72F RANGE SUNDAY BEFORE A WARMING TREND
ARRIVES MONDAY AND TUESDAY. HAVE LEANED TOWARD THE ENSEMBLE MEANS
FOR MAXES OVER THE WEEKEND AS LONGER DAYLIGHT HOURS TEND TO MODERATE
THESE AIR MASSES EFFECTIVELY. 500MB HEIGHT RISES OF 40-60M SUNDAY AND
AGAIN ON MONDAY ALLOW LOW LEVEL WAA TO PUSH DAYTIME READINGS UPWARD
AND THESE SHOULD BE VERY CLOSE TO THE NORMALS FOR THIS TIME IN APRIL
WITH LOWS IN THE BACK INTO THE 50S AND HIGHS 75-80F BY TUESDAY./40/
&&
.AVIATION...WIDESPREAD IFR CONDITIONS ARE ASSOCIATED WITH A LARGE
RAIN/THUNDERSTORM COMPLEX MOVING ACROSS THE FORECAST AREA THIS AFTN.
WE WILL SEE IMPROVING CONDITIONS FROM WEST TO EAST AS WE GO THROUGH
LATE AFTERNOON WITH VFR CONDITIONS DEVELOPING FROM THE EVENING INTO
THE OVERNIGHT HOURS...ESPECIALLY AT GLH/GWO/JAN/HBG. IFR CATEGORY
STRATUS MAY BE GENERATED OVER EASTERN MS (GTR/MEI) IN THE WEAK COLD
ADVECTION PATTERN...AND WITH THE CLEARING SKIES AND DECREASING WIND
FARTHER WEST...AREAS OF FOG MAY DEVELOP AFTER 06Z AND PERSIST DURING
THE MORNING HOURS. ANY FOG/STRATUS WILL MIX OUT BY AROUND 15Z
WEDNESDAY MORNING AND VFR CONDITIONS CAN BE EXPECTED THROUGH
WEDNESDAY AFTERNOON/EVENING. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 48 75 49 81 / 31 2 0 0
MERIDIAN 52 76 48 81 / 83 7 0 0
VICKSBURG 49 74 48 81 / 11 0 0 0
HATTIESBURG 55 79 52 83 / 71 5 0 0
NATCHEZ 49 73 49 78 / 20 0 0 0
GREENVILLE 49 75 50 80 / 9 0 0 0
GREENWOOD 49 74 49 81 / 19 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
28/40/EC
AREA FORECAST DISCUSSION
NWS GLASGOW MT
925 PM MDT WED APR 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
RADAR SHOWING ECHOES CONCENTRATED OVER THE NORTH-CENTRAL ZONES BUT
SHOWERS ARE ALSO FALLING IN THE EASTERN ZONES WITH A FEW HUNDREDTHS
ACCUMULATED AT SIDNEY AND GLENDIVE. NAM AND GFS CONTINUE TO LOOK TOO
WET BUT HRRR MODEL PULLING PRECIP POSSIBLY OUT TO OUR EAST TOO SOON.
AREAS SOUTH OF A MALTA TO GLENDIVE LINE AT THIS POINT LOOK TO REMAIN
DRY FOR THE NIGHT WHILE SHOWERS SHOULD FILL IN FROM SCOBEY TO
PLENTYWOOD.
ALSO RAISED TEMPS SLIGHTLY WITH THE CURRENT HIGHER DEWPOINTS AND
CLOUDCOVER...SHOULD NOT BE COLD ENOUGH FOR SNOW IN THE NE...SO
REMOVED THAT MENTION. REST OF FORECAST APPEARS TO BE ON TRACK. JAMBA
PREVIOUS DISCUSSION...
AN APPROACHING SHORTWAVE OVER WESTERN MONTANA HAS PRODUCED A
SLIGHT INCREASE IN A THERMAL RIDGE OVER EASTERN MONTANA. THIS HAS
STARTED TO PUSH THE FRONTAL BOUNDARY LEFT OVER FROM YESTERDAY
NORTH AND EASTWARD. ALONG THIS BOUNDARY IS WHERE MOST OF THE
PRECIPITATION IS FALLING. OBSERVATIONS HAVE BEEN IN THE
NEIGHBORHOOD OF .03 TO .08 HUNDREDTHS OF AN INCH OF QPF. KEPT POPS
IN THE LIKELY CATEGORY FOR THIS EVENING AND LEFT THE CHANCE OF
WETTING RAIN VERY LOW AND QPF AMOUNTS UNDER A TENTH OF AN INCH.
TONIGHT WILL CONTINUE WITH HIGH POP LOW QPF AND LOW WETTING RAIN.
TODAY`S PRECIPITATION HAS GIVEN ME SLIGHTLY MORE CONFIDENCE IN THE
MODELS WHEN IT COMES TO QPF. THE ACTUAL AMOUNT OF RAINFALL IS STILL
LESS THAN THE MODEL QPF BUT AT LEAST WE CAN FINALLY SAY WE HAD
MORE THEN JUST A TRACE. ALONG THE INTERNATIONAL BORDER RAIN LIKELY
TO CHANGE OVER TO A RAIN SNOW MIX AND THEN ALL SNOW BEFORE
SUNRISE. ACCUMULATION WILL BE VERY LIGHT AND REMAIN LESS THEN A
1/2 OF AN INCH.
COLD FRONT WILL ACTUALLY COME THROUGH IN THE MORNING AHEAD OF THE
SHORTWAVE OUT WEST. THE WINDS SWITCH TO THE WEST ACROSS THE AREA
AND WE WILL CONTINUE TO SEE PRECIPITATING ACROSS THE WESTERN
ZONES...AMOUNTS WILL REMAIN LESS THEN A TENTH OF AN INCH. THE
ONE ISSUE THAT COULD INCREASE POPS THURSDAY AFTERNOON IS VERY
STEEP LAPSE RATES WHICH COULD SPARK A THUNDERSTORM AND CREATE
SMALL AREAS OF HIGHER RAINFALL. THURSDAY NIGHT PRECIPITATION WILL
MOVE INTO THE DAKOTAS AND WE WILL SEE DRYING FROM WEST TO EAST.
FRIDAY A LOW MOVES OFF OF THE ALBERTA ROCKIES AND SLIDES ACROSS
SASKATCHEWAN INTO NORTH DAKOTA IN THE NORTHWEST FLOW AHEAD OF THE
BUILDING RIDGE. THIS MIGHT BRING ANOTHER SLIGHT CHANCE OF WETTING
RAINS WITH STRONGER SHOWERS ACROSS THE NORTHERN TIER OF ZONES.
RSMITH
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
LONG TERM FORECAST PERIOD IS ACCENTUATED BY A SIGNIFICANT UPPER
LEVEL RIDGE OVER THE WESTERN STATES WHICH WILL BRING MUCH WARMER
TEMPERATURES TO NORTHEAST MONTANA SATURDAY THROUGH TUESDAY WITH
THE HOTTEST TEMPERATURES EXPECTED ON MONDAY.
AS THE NEXT STORM SYSTEM TRIES TO BREAK DOWN THIS RIDGE TOWARD THE
MIDDLE OF NEXT WEEK...SOME INCONSISTENT MODEL DISCREPANCIES REDUCE
THE FORECAST CONFIDENCE QUITE A BIT BEGINNING ON TUESDAY. THE EC
BRINGS A QUICK AND SHALLOW TROUGH WITH A SMALL CLOSED LOW GLANCING
US ON OUR NORTH TUESDAY MORNING THROUGH TUESDAY AFTERNOON WHILE
THE GFS BARELY MAKES IT OVER THE CONTINENTAL DIVIDE BEFORE
DISAPPEARING COMPLETELY INTO A MORE ZONAL FLOW. TRIED TO SHOW MORE
OF A COMPROMISE AND BLEND WITH THESE MODEL SOLUTIONS IN THE FAR
EXTENDED PERIOD. THE ATTENDANT COLD FRONT ON WEDNESDAY COULD DROP
TEMPERATURES BY AT LEAST 15 DEGREES. BMICKELSON
PREVIOUS LONG TERM DISCUSSION...THE LAST IN A SERIES OF SEVERAL
SHORTWAVE DISTURBANCES FROM THE W MOVES OUT OF THE AREA FRI NIGHT.
THEN A BUILDING UPPER RIDGE FROM THE S OVER THE WEEKEND BRINGS
SUNNY AND WARMER WEATHER. THE RIDGE BECOMES QUITE STRONG WITH 850
MB TEMPS TO AS HIGH AS 18-24C MONDAY. THICKNESSES VALUES REACH 570
DM. THIS SHOULD DRIVE NE MT HIGHS INTO THE UPPER 70S TO MID
80S...WHICH WILL APPROACH RECORD HIGHS FOR THE DATE AT SOME
LOCATIONS.
MODELS AGREE WITH A MOSTLY DRY...BUT FAIRLY STRONG COLD FRONT FROM THE
WNW MOVING ACROSS THE AREA TUE...WHICH WILL START A COOLING TREND.
THE ASSOCIATED UPPER TROUGH LAGS BEHIND...AND MODELS HAVE VARIED
ON TIMING...INTENSITY...AND MOVEMENT WITH THIS. ECMWF HAS BEEN
TOO QUICK TO BREAK DOWN THE RIDGE. MEANWHILE CMC GEM DEFLECTS BOTH
COLD FRONT AND TROUGH TO OUR N AND KEEPS THE RIDGE OVER OUR AREA...WHICH
DOES APPEAR POSSIBLE. GFS ENSEMBLES INDICATE THAT ANY OF THESE AND
OTHER SOLUTIONS ARE POSSIBLE TOO...SO LOW CONFIDENCE AT THE END OF
THE PERIOD. PREFER THE 00Z OPERATIONAL GFS THOUGH WHICH IS MORE
OF A MIDDLE GROUND SOLUTION...AND DOES BRING AT LEAST A SLIGHT
CHANCE OF SHOWERS BY WED. SIMONSEN
&&
.AVIATION...
THIS STORM SYSTEM ACROSS NORTHEAST MONTANA WILL BE SLOW-MOVING THROUGH
THURSDAY WITH GENERAL LIGHT RAIN TONIGHT THROUGH THURSDAY MORNING
TRANSITIONING TO POSSIBLE THUNDERSTORMS THURSDAY AFTERNOON. EXPECT
FLIGHT CONDITIONS TO WORSEN FROM TONIGHT TO IFR AND LIFR OVERNIGHT
AND THROUGH THE MORNING HOURS. TAF AMENDMENTS CAN BE EXPECTED
UNTIL CEILINGS BEGIN TO LIFT TOWARD THE END OF THIS TAF CYCLE. BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1021 AM MDT TUE APR 17 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
UPDATED TO THE FORECAST TO MAKE A FEW MINOR CHANGES. LOOKING AT
FORECAST SOUNDING FROM BUFKIT AND AWIPS BUFR SOUNDING DECIDED TO
GO AHEAD AND LAUNCH A LAKE WIND ADVISORY FROM NOON UNTIL 9 PM THIS
EVENING. NORTHWEST WINDS OF 15 TO 25 MPH ARE LIKELY WITH THE
OCCASIONAL GUST UP TO 30 BEING MIXED TO THE SURFACE. RAISED THE
DAY TIME HIGHS SLIGHTLY SINCE WE ARE SEEING MORE CLEARING WITH
PARTLY CLOUDY SKIES ACROSS NEMONT. SOLAR RADIATION SHOULD BE ABLE
TO PENETRATE WHAT CLOUD COVER THERE IS TO WARM THINGS UP INTO THE
LOWER TO MID 60S THIS AFTERNOON.
ALSO THE 12Z NAM/GFS AND THE LATEST HRRR MODEL RUN INDICATES
POSSIBLE ISOLATED THUNDER WITH THE SCATTERED RAIN SHOWERS THIS
AFTERNOON. MODELS ARE HINTING AT A POSSIBLE .10 OF AN INCH OF QPF
SOUTH OF THE MISSOURI RIVER THIS AFTERNOON AND EVENING. THE
DISAPPOINTMENT IN THE MODELS QPF OUTPUT HAS BEEN SUBSTANTIAL FROM
MYSELF AND OTHER FORECASTER HERE. SO WITH THIS IN MIND DON`T COUNT
ON ANYTHING OVER A FEW HUNDREDTHS OF AN INCH OF PRECIPITATION
SOUTH OF THE MISSOURI RIVER THIS AFTERNOON AND EVENING. RSMITH
PREVIOUS DISCUSSION...SHORTWAVE SYSTEM FROM THE W MOVING INTO THE
AREA TODAY WITH MODELS INDICATING SOME SOME SPLITTING OF MOISTURE
AND UPPER SUPPORT. WARM FRONT SHOWERS THIS MORN WILL BE MAINLY
OVER CANADA AND OUR EXTREME N. A WEAK PACIFIC COLD FRONT WILL
BRING DOWN SLOPE WARMING AND DRYING INTO MUCH OF THE REST OF OUR
AREA...WITH MOISTURE HEADING MOSTLY INTO BYZ CWA. A SECONDARY
CANADIAN COLD FRONT ARRIVES LATE AFTERNOON AND EVE FROM THE NNW.
MORE MODEL VARIATION ON TIMING AND QPF...BUT GENERALLY NOT
EXPECTING MUCH.
MODELS SHOW 850-700 MB LAYER MB LAYER WINDS WILL BE 20-30 KT
EARLY MORNING...BUT DROPPING OFF TO 15-20 KT IN THE AFTERNOON WHEN
WE MIX DRY ADIABATICALLY TO THAT LEVEL. THIS WILL APPROACH...BUT
LIKELY FALL JUST A BIT SHORT OF LAKE WIND ADVISORY CRITERIA. MOS
VERY CLOSE TOO...BUT A LITTLE SHORT ALSO.
THE EDGE OF ANOTHER POLAR HIGH PRESSURE...CENTERED WELL TO OUR N
IN CANADA BRUSHES OUR AREA TONIGHT...GIVING CLEARING AND JUST A
LITTLE COLDER AIR BACK IN.
MODELS ARE QUICKER AND IN BETTER AGREEMENT WITH ANOTHER SYSTEM
ARRIVING WED AFTERNOON AND NIGHT. THEY HAVE TRENDED STRONGER AND
MUCH MOISTER TOO. SURFACE SYSTEM FORMS OVER W MT...AND MOVES ESE ACROSS
THE SC-SE MT BORDER WITH WY. FIRST IMPRESSIONS ARE THAT THIS COULD
ONLY IMPACT OUR EXTREME S...BUT THERE IS A SURPRISINGLY AMOUNT OF
LIFT AND MOISTURE FLUNG WELL N OF THAT...AS THERE IS A MODEST
INVERTED TROUGH. MODELS HAVE BEEN WAY TOO MOIST LATELY...AND
APPEAR THAT WAY AGAIN AS GFS HAS UP TO 0.4 QPF. HOWEVER THERE IS
DECENT AGREEMENT ON SIGNIFICANT QPF AND THE LOCATION...EXCEPT THE
NAM. SATELLITE CHANNELS SHOWING AN IMPRESSIVE LONG STREAM OF
MOISTURE INTO SEVERAL WAVES IN WESTERLY JET ACROSS MUCH OF THE PACIFIC.
SO...CHANCE POPS FOR MOST OF THE AREA FOR THIS SYSTEM APPEAR
REASONABLE.
THE AIR MASS NOT UNSTABLE WED NIGHT...SO WILL GO WITH STRATIFORM
LIGHT RAIN CHANCES. 850 MB TEMPS BELOW 0C IN OUR NORTHERN-MOST
ZONES...AND POSSIBLE LATE NIGHT ARRIVAL TIME FAVORABLE FOR
POSSIBLE SNOW IN PLACES. WILL LEAVE OUT ANY SNOW AMOUNTS THOUGH. FOR THE
REST OF THE AREA...IT COULD BE A RATHER COLD RAIN...AND NOT FAR
FROM TURNING TO SNOW. LINGERING PRECIP TURNS SHOWERY AS IT WARMS
UP AND TAPERS OFF IN THE THU AFTERNOON. SIMONSEN
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED BEINGS THURSDAY NIGHT WITH AN UPPER TROUGH MOVING OUT
OF THE REGION AND RIDGING BUILDING IN. STILL A FEW SHORTWAVES
NOTED IN THE FLOW TO KEEP A MENTION OF POPS GOING OVER THE REGION
THROUGH FRIDAY NIGHT. THIS WILL ALSO BE THE COOLEST PERIOD OF THE
FORECAST. DO NOT EXPECT MUCH QPF WITH ANY OF THE SHORT WAVES
MOVING THROUGH THE FLOW. BOTH THE EC AND GFS SEEM IN FAIR
AGREEMENT WITH THE PATTERN.
SATURDAY INTO EARLY NEXT WEEK... A LARGE RIDGE SETTLES IN OVER
NORTHEAST MONTANA. DRY IS FOR CERTAIN... TEMPERATURES DID STAY
SOMEWHAT CONSERVATIVE... BY MONDAY INTO TUESDAY WE COULD BE WELL
INTO THE 80S ACROSS EASTERN MONTANA. DO EXPECT SOME FIRE WEATHER
ISSUES EARLY NEXT WEEK. ANY RIPPLES IN THE UPPER FLOW OVER THE
MOUNTAINS COULD SPARK A THUNDERSTORM. THE MID LEVELS ARE FORECAST
TOO WARM FOR SURFACE CONVECTION. AT THIS TIME ITS JUST TOO FAR OUT
TO BE TRYING TO PREDICT VERY ISOLATED DRY THUNDERSTORMS. PROTON
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR ALL TAF SITES
THROUGHOUT THE ENTIRE TAF CYCLE. SOME ISOLATED RAIN SHOWERS CAN
BE EXPECTED ACROSS THE REGION INTO THIS EVENING...HOWEVER FLIGHT
CONDITIONS WOULD BE LOWERED TO MVFR ONLY IF ONE OF THESE SMALL
SHOWERS MOVE DIRECTLY OVER A TAF SITE. EXPECT VICINITY RAIN SHOWERS
NEAR KGGW AND KOLF BY MID AND NEAR KSDY AND KGDV BY MID AFTERNOON.
BREEZY WINDS FROM THE WEST THIS AFTERNOON WILL CALM FROM THE NORTH
TONIGHT. PROTON/BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR FOR FORT PECK
LAKE IN THE FORT PECK LAKE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1025 AM EDT TUE APR 17 2012
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL REMAIN IN CONTROL EARLY TODAY. A COLD
FRONT WILL DROP SOUTHEAST TO AND ACROSS THE LATE TODAY THROUGH
WEDNESDAY... INCREASING THE CHANCES OF SHOWERS AND THUNDERSTORMS.
THIS FRONT WILL STALL JUST OFFSHORE THURSDAY AND THEN DISSIPATE
FRIDAY. A STRONGER COLD FRONT IS EXPECTED SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...A VERY SLOW MOVING COLD FRONT WHICH IS
CURRENTLY LOCATED FROM THE OUTER BANKS TO THE MIDLAND OF SOUTH
CAROLINA WILL BE THE FOCUS OF TODAYS WEATHER. THIS FRONTAL
BOUNDARY WILL SLOWLY SHIFT ACROSS THE REGION THROUGH TONIGHT.
STILL LOTS OF DRY AIR AROUND WITH THE HIGH PRESSURE AREA ALOFT.
THE 12Z NAM AND 11 UTC HRRR ARE SHOWING WIDELY SCATTED CONVECTION
STARTING BETWEEN 19 AN 20 UTC ALONG THE FRONTAL BOUNDARY FROM
HOLLY RIDGE NORTH CAROLINA TO LUMBERTON TO SOME ISOLATED
CONVECTION SOUTH THE FRONT OVER THE SOUTH CAROLINA COUNTIES.
AS MENTION EARLIER...LOTS OF PROBLEMS FOR DETERMINING THE COVERAGE
OF CONVECTION ALONG THE FRONT. BEST LIFTING WILL REMAIN TO THE WEST...
STILL FAIRLY DRY ALOFT UNTIL THIS AFTERNOON. THE 12 UTC NAM IS
SHOWING A THIN LAYER OF MOISTURE AROUND 5000 TO 8000 THOUSAND
FEET...BUT IT IS NOT DEEP. THE BEST SURFACE BASED CAPES OF 1000
TO 1300 J/KG ARE SEEN RUNNING JUST AHEAD OF THE BOUNDARY FROM DARE
COUNTY DOWN THE COAST OF SOUTHEAST NORTH CAROLINA AND OVER INTO
SOUTH CAROLINA JUST SOUTH OF CHARLOTTE. SO IF THIS INITIALIZATION
IS CORRECT THEM WE COULD EXPECT WIDELY SCATTERED TO SLOWLY SCATTERED
CONVECTION ALONG THIS BOUNDARY.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM TUESDAY...COLD FRONT WILL BE STALLED NEAR THE SOUTHERN
BORDER OF THE CWA EARLY WEDNESDAY. IN THE MID LEVELS A WEAKENING
SHORTWAVE TROUGH WILL BE APPROACHING FROM THE WEST. THIS WILL LEAD
TO A SENSE OF LOW LEVEL WARM ADVECTION THAT WILL SPREAD WEST TO EAST
ACROSS THE REGION. WARMTH AND MOISTURE WILL THEN OVERRUN THE SURFACE
WEDGE OF COOL AIR IN PLACE. THE UPPER TROUGHINESS AND WAA WILL DRAW
THE SURFACE FRONT BACK UP TO PARALLEL THE COASTLINE WHILE IT REMAINS
OFFSHORE WEDNESDAY NIGHT INTO THURSDAY. THE SURFACE WEDGE WILL ALSO
WEAKEN CUTTING DOWN ON THE STRENGTH OF THE SENSE OF ISENTROPIC
UPGLIDE MAKING RAIN CHANCES GO DOWN AS THE DAY WEARS ON. BY THURSDAY
NIGHT BOTH FEATURES WILL HAVE WEAKENED SUFFICIENTLY THAT RAINFALL
CAN BE TAKEN OUT OF THE FORECAST.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...WEAK FLOW/SUBTLE MID LEVEL RIDGING AND POORLY
DEFINED SURFACE GRADIENT IN PLACE EARLY FRIDAY. BY AFTERNOON THE
FORMER MOVES OFF THE COAST AND A FEW SHORTWAVES MAY MOVE THROUGH THE
FLOW CALLING FOR SOME LOW POPS. TEMPERATURES WILL RUN A FEW DEGREES
ABOVE CLIMO. MEANWHILE A SHARPENING UPPER TROUGH WILL BE DEVELOPING
TO OUR WEST. THIS WILL MAKE FOR A VERY UNSETTLED WEEKEND AS THE
TROUGH SHARPENS FURTHER ON SATURDAY AND LOW PRESSURE DEVELOPS ALONG
THE EASTBOUND COLD FRONT. WETTEST OF THE WEATHER LOOKS LIKE SATURDAY
AFTERNOON AS WIDESPREAD SHOWERS AND THUNDERSTORMS SEEM LIKELY. UPPER
TROUGH MAY TILT TO THE NEGATIVE AND LOW LEVEL JET LOOKS STRONG SO
ORGANIZED SEVERE WEATHER LOOKS POSSIBLE. WRAPAROUND MOISTURE AND
IMPRESSIVE COLD ADVECTION SHOULD BE ON TAP FOR SUNDAY. GIVEN THE
LARGE AMPLITUDE AND DISTANT TIME FRAME MODEL SOLUTIONS VARY
CONSIDERABLY. THE GFS LOOKS TOO FAR SOUTH AND CUTS OFF TOO
AGGRESSIVELY TO ARRIVE AT A SOLUTION THAT APPEARS QUITE
CLIMATOLOGICALLY UNLIKELY. THE EC HAS BEEN QUITE CONSISTENT AND
LOOKS MORE POSSIBLE FROM A CLIMO STANDPOINT AND IS WELL SUPPORTED BY
THE CANADIAN SOLUTION. THESE MODELS HAVE BEEN SHOWING A VERY STORMY
EAST COAST SCENARIO AND VERY STRONG COLD ADVECTION INTO THE
SOUTHEAST EARLY NEXT WEEK.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...THERE IS HIGH CONFIDENCE OF VFR THIS MORNING INTO THE
MID-AFTERNOON HOURS. CONFIDENCE OF VFR LOWERS AFTER THAT TIME AS
SHOWERS AND THUNDERSTORMS DEVELOP ALONG A PRE-FRONTAL TROUGH LBT TO
FLO...AND ON THE SEA BREEZE BOUNDARY. THERE SHOULD BE LITTLE CHANCE
OF OCCURRENCE AT ANY ONE TERMINAL AS CONVECTION WILL BE
ISOLATED...AND ACTIVITY FORMING ON THE SEA BREEZE SHOULD OCCUR WHEN
IT IS LOCATED INLAND FROM THE COAST BUT NOT AS FAR INLAND AS FLO/LBT.
BUT BY EVENING CONVECTIVE COVERAGE IS EXPECTED TO INCREASE AS A COLD
FRONT APPROACHES...WITH THE BEST CHANCES OF OCCURRENCE AT THE FLO
LBT AND ILM TERMINALS. CONVECTION DECREASES AFTER 06Z BUT
SHOWERS/-RA WILL REMAIN LIKELY THOUGH THE END OF THE TAF VALID
PERIOD AS THE COLD FRONT DROPS TO NEAR THE CRE/MYR TERMINALS BY
SUNRISE.
WEST SOUTHWEST TO WEST WINDS WILL BECOME LIGHT NORTHERLY LATER THIS
MORNING AT LBT BEHIND THE PRE-FRONTAL TROUGH...AND MAY CAUSE WINDS
TO BE JUST BE LIGHT AND VARIABLE AT FLO/LBT ALL DAY. WINDS WILL
BECOME SOUTH AT THE CRE/MYR TERMINALS BY LATE MORNING AND AT THE ILM
TERMINALS EARLY AFTERNOON AS THE SEA BREEZE MOVES INLAND.
POST-FRONTAL BR DEVELOPMENT WILL BECOME MORE LIKELY AFTER MIDNIGHT
AS COOLER AIR FILTERS IN BEHIND THE COLD FRONT...WITH VISIBILITIES
DROPPING TO AT LEAST MVFR. THINK THE CHANCE OF IFR WILL BE LOW DUE
TO CLOUD COVER.
EXTENDED OUTLOOK...POSSIBLE TEMPO REDUCED FLIGHT CONDITIONS DUE TO
SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY...WITH THE BEST CHANCE
FRIDAY INTO SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...SOUTHWEST WINDS OF 10 KNOTS ARE BLOWING
OVER THE WATERS AND SEAS ARE GENERALLY AROUND 2 FEET. SO NO
CHANGES ARE PLANNED. PREVIOUS DISCUSSION FOLLOWS...
HIGH PRESSURE OFF THE SOUTHEAST U.S. COAST WILL WEAKEN LATER TODAY
AS A COLD FRONT DROPS SOUTH THROUGH VIRGINIA AND NORTH
CAROLINA...REACHING THE COASTAL WATERS NEAR CAPE FEAR AROUND SUNSET.
SOUTHWEST WINDS OUT AHEAD OF THE FRONT WILL TURN EASTERLY NEAR AND
NORTH OF CAPE FEAR THIS EVENING...THEN NORTHEASTERLY TONIGHT AS HIGH
PRESSURE CENTERED OVER THE EASTERN GREAT LAKES TRIES TO BUILD SOUTH.
THE FRONT WON`T MAKE TREMENDOUS PROGRESS SOUTHWARD HOWEVER...AND THE
SOUTH CAROLINA COASTAL WATERS WILL PROBABLY NOT SEE THIS FRONT MOVE
THROUGH TONIGHT. SOUTHWESTERLY WINDS HERE THIS MORNING WILL BACK TO
SOUTHERLY WITH THE SEABREEZE THIS AFTERNOON AND REMAIN SOUTHERLY
TONIGHT. WAVE MODELS SHOW NO SIGNIFICANT SWELL TO AFFECT THE
AREA...AND SHORT PERIOD WIND WAVES SHOULD AVERAGE 2-3 FT THROUGH
TONIGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...COLD FRONT WILL BE IN THE AREA FOR MUCH OF THE
PERIOD. ITS EXACT POSITION WILL BE RATHER UNCERTAIN FOR A GOOD PART
OF THE PERIOD MAKING THE EXACT DIRECTION OF THE WIND FORECAST IN
NEED OF POSSIBLE REFINEMENT. HOWEVER AS USUAL WITH A FRONT NEARBY
WIND SPEED WILL BE QUITE LOW. THE BOUNDARY WILL BE OFF TO THE SOUTH
EARLY WEDNESDAY BRINGING ON ONSHORE AND NORTHERLY WIND. AS THE FRONT
DRAWS CLOSER TO THE COAST WED NIGHT INTO THURSDAY THERE COULD BE A
SLIGHT DECREASE IN THE FLOW. SEAS WILL BE IN THE 2 TO 3 FT RANGE
MOST OF THE SHORT TERM. THE ONSHORE COMPONENT WILL ACT TO DIMINISH
THE NEARSHORE/OFFSHORE WAVE HEIGHT GRADIENT.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...A SOUTHERLY FLOW WILL BECOME RE-ESTABLISHED
EARLY IN THE PERIOD AS HIGH PRESSURE CONSOLIDATES OFF THE MID
ATLANTIC COAST. A STRONG COLD FRONT WILL BE APPROACHING FROM THE
WEST HOWEVER AND THIS WILL EVENTUALLY LEAD TO A DRAMATIC INCREASE IN
BOTH WIND AND WAVES. THERE IS SOME UNCERTAINTY REGARDING THE SPEED
OF THIS BOUNDARY (BUT MOST OF THE FORECAST UNCERTAINTY INVOLVES THE
POST-FRONTAL REGIME BEYOND THE VALID TIME OF THE LONG TERM). CURRENT
FORECAST WILL SHOW A RAMP UP TO WHERE SCEC HEADLINES WILL BE NEEDED
BUT IN LIGHT OF THE ANTICIPATED FURTHER DETERIORATION SMALL CRAFT
ADVISORIES APPEAR MUCH MORE LIKELY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...III
LONG TERM...BACON
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
634 PM CDT WED APR 18 2012
.DISCUSSION...
THE OVERALL FORECAST IS IN GOOD SHAPE...HOWEVER...DID INCREASE
POPS ESPECIALLY ACROSS THE NORTHWEST AND NORTH CENTRAL TONIGHT
BASED UPON THE 18 UTC MODEL CONSENSUS AND THE LATEST HRRR SIMULATED
COMPOSITE REFLECTIVITY. THE BIGGEST CHALLENGE WILL BE
PRECIPITATION TYPE. COOLING VIA EVAPORATION OF PRECIPITATION IN
THE LOWER LAYERS OF THE ATMOSPHERE SHOULD ALLOW SURFACE WET BULB
TEMPERATURES TO COOL TO NEAR FREEZING ALONG THE INTERNATIONAL
BORDER...WITH THE MID TO UPPER 30S ALONG US HIGHWAY 2 BY 12 UTC
THURSDAY. THEREFORE...SNOW MAY MIX WITH THE RAIN BETWEEN THE 09-12
UTC TIME FRAME ACROSS THE NORTHWEST AND FAR NORTH CENTRAL.
HOWEVER...THE SMALL WINDOW FOR SNOW AND MARGINALLY SUPPORTIVE WET
BULB HEIGHTS SHOULD LIMIT ACCUMULATIONS TO AN INCH OR LESS. THIS
IS SUPPORTED BY HPC AND THE BUFKIT-COBB OUTPUT.
&&
.AVIATION...
A BAND OF PRECIPITATION ACROSS EASTERN MONTANA AND FAR WESTERN
NORTH DAKOTA AS OF 23 UTC WILL CONTINUE TO SPREAD INTO WESTERN AND
CENTRAL NORTH DAKOTA TONIGHT. RAIN SHOWERS ARE ALREADY ONGOING AT
KDIK...WITH RAIN EXPECTED TO BEGIN AT KISN BY 03 UTC AND KMOT AND
KBIS BY 05-06 UTC. MVFR CONDITIONS IN RAIN ARE EXPECTED FOR THESE
TERMINALS...WITH IFR POSSIBLE BY 09-12 UTC AT KISN...KMOT AND
KDIK. SOME SNOW MAY MIX WITH THE RAIN AT KISN AND KMOT EARLY
THURSDAY MORNING. WIDESPREAD RAIN SHOWERS ARE EXPECTED ACROSS ALL
OF WESTERN AND CENTRAL NORTH DAKOTA ON THURSDAY...WITH MVFR
CONDITIONS. THUNDER IS ALSO POSSIBLE AT KDIK THURSDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
703 AM CDT TUE APR 17 2012
.DISCUSSION...LOW PRESSURE OVER FAR SOUTHWEST SASKATCHEWAN WILL
MOVE EAST SOUTHEAST INTO FAR WESTERN NORTH DAKOTA AROUND 18 UTC
TODAY. WARM SOUTHERLY FLOW AHEAD OF THE LOW HAS WARMED
TEMPERATURES ACROSS THE WEST ABOVE FORECAST VALUES. READINGS ARE
GENERALLY AROUND 40 DEGREES ACROSS THE FAR WEST. FARTHER
EAST...TEMPERATURES REMAIN IN THE MID 20S TO LOWER 30S BUT EXPECT
TEMPERATURES HERE TO BEGIN TO RISE QUICKLY AS MID AND HIGH LEVEL
CLOUDS ENCOMPASS THE REGION AND SURFACE FLOW INCREASES FROM THE
SOUTH. MADE SOME MINOR ADJUSTMENTS TO SKY COVER AND ALSO
TEMPERATURES TO ACCOUNT FOR CURRENT WARMER TEMPERATURES WEST.
LATEST SHORT TERM MODELS ARE KEEPING THE MAJORITY OF THE
PRECIPITATION THIS MORNING CONFINED TO THE NORTHERN TIER COUNTIES
OF WESTERN NORTH DAKOTA. 07 UTC HRRR IS FARTHER SOUTH WITH
REFLECTIVITIES BUT THIS IS OVERDONE WHEN COMPARING TO CURRENT
RADAR TRENDS. THUS WE DROPPED POPS DOWN TO SLIGHT CHANCE OVER THE
SOUTHWEST THIS MORNING.
&&
.AVIATION......MID AND HIGH LEVEL CLOUDINESS IS INCREASING ACROSS
THE WESTERN AND CENTRAL NORTH DAKOTA. SOUTHERLY SURFACE FLOW IS
OCCURRING OVER THE AREA WITH SURFACE HIGH PRESSURE MOVING EAST OF
THE JAMES RIVER VALLEY. A LOW PRESSURE SYSTEM CURRENTLY OVER
SOUTHWEST SASKATCHEWAN WILL MOVE QUICKLY SOUTHEAST INTO CENTRAL
NORTH DAKOTA BY THIS AFTERNOON...AND INTO MINNESOTA BY 12 UTC
THURSDAY. THIS WILL BRING A CHANCE OF SHOWERS AND POSSIBLY
AFTERNOON/EARLY EVENING THUNDERSTORMS TO THE AREA. THE LEADING
EDGE OF PRECIPITATION IS ABOUT TO PUSH INTO THE FAR NORTHWEST.
VFR CEILINGS ARE EXPECTED TODAY AHEAD OF THE SURFACE LOW. AS THE
LOW TRACKS EAST TONIGHT...WRAP AROUND MOISTURE AND SCATTERED MVFR
CEILINGS ARE POSSIBLE. SOUTHERLY FLOW AHEAD OF THE LOW WILL SHIFT
NORTHWEST TO NORTH BEHIND THE SYSTEM.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM....TWH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
306 AM EDT TUE APR 17 2012
.SYNOPSIS...
A COLD FRONT WILL CLEAR SOUTHEAST PENNSYLVANIA OVERNIGHT. HIGH
PRESSURE WILL BUILD SOUTHEAST ACROSS THE AREA FOR MID WEEK. A
DEEPENING TROUGH WILL LIKELY FORM OVER THE EASTERN CONUS BY THE
WEEKEND OR EARLY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
COLD FRONT PUSHING INTO EXTREME EASTERN PA AT 05Z. WILL REMOVE
LAST MENTION OF SHRA FROM THE FCST...AS MUCH DRIER AIR IS NOW
WORKING INTO CENTRAL PA ON A GUSTY WNW WIND. TIGHT PRES GRADIENT
WILL REMAIN OVER THE AREA...LEADING TO BREEZY CONDS EARLY THIS
MORNING. BLEND OF RUC13 AND LAMP GUIDANCE INDICATE TEMPS SHOULD
BOTTOM OUT AT DAWN FROM THE L40S NW MTNS...TO THE U50S ACROSS THE
LOWER SUSQ VALLEY. UPSTREAM SATL IMAGERY AND MDL DATA BOTH SUGGEST
AN INCREASE IN HIGH CLOUDS TOWARD DAWN OVER THE CENTRAL MTNS...AS
CIRRUS STREAMS NORTH FROM DEVELOPING WAVE OVR THE SOUTHEAST CONUS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
00Z MDLS NOW INDICATE A FAIR AMT OF CIRRUS WILL BE OVER CENTRAL
AND WESTERN PA LATER TODAY...AS HIGH LVL MOISTURE CONTINUES TO
STREAM NORTH FROM DEVELOPING WAVE OVR THE SE CONUS. WILL TERM SKY
COVER AS /PTSUNNY/ FOR MOST OF THE REGION AND HAVE LEANED TOWARD
THE SLIGHTLY COOLER MAV NUMBERS WITH MAX TEMPS FROM THE M50S NW
MTNS...TO L70S LOWER SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
NOT A LOT OF CHANGE FROM YESTERDAY. MAIN THING WAS TO BACK OFF
THE COLD AIR AND MENTION OF SNOW FOR THE WEEKEND.
STILL A LOT OF SPREAD IN THE FCST FOR THE WEEKEND AND EARLY
NEXT WEEK. GFS AND HPC CHARTS NOW HAVE IN MORE IN THE MILDER
AIR BEFORE LATER SUNDAY INTO MONDAY. CUTOFF NOW FORMS FURTHER
SOUTH NOW...AND LATER IN TIME.
ASIDE FROM THE WEEKEND...LEFT THINGS CLOSE TO WHAT WE HAD.
FOR TUESDAY NIGHT...MODELS NOT SO COLD NOW...BUT STILL DOWN
NEAR FREEZING OR JUST BELOW ACROSS NORTHERN PA AND SOUTHERN
NY...BUT FOR NOW HELD OFF ON FREEZE WATCH.
FOR WED...DID EDGE TEMPS DOWN ACROSS THE SOUTH...EXPECT MORE
CLDS. WENT WITH A DRY FCST FOR WED. GFS FURTHER NORTH WITH
MOISTURE...BUT THE AIRMASS THAT COMES IN LATE TONIGHT IS
QUITE DRY.
DID EDGE POPS OFF ON THU AND FRIDAY...MODELS FURTHER NORTH
NOW WITH THE MOISTURE.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE OVERNIGHT. GUSTY WINDS WILL GRADUALLY
SHIFT TO THE WEST BEFORE DIMINISHING BY 09Z AS THE REGION DECOUPLES.
WHILE THE GRADIENT SLACKENS A LITTLE TONIGHT AND TUES...DAYTIME
MIXING TUES COULD STILL MAKE GUSTS INTO THE 20-25KT RANGE ONCE
AGAIN. OTHERWISE VFR AS THE HIGH PRESSURE BUILDS IN. CLEAR AND
CALM TUES NIGHT.
OUTLOOK...
WED-FRI...VFR. MAY SEE SOME SHRA FRI AS NEXT FRONT APPROACHES.
SAT...MVFR CIGS/VIS IN SHRA.
&&
.FIRE WEATHER...
TUESDAY WILL FEATURE LOWER WIND SPEEDS AND GUSTS AS THE GRADIENT
SLACKENS A BIT WITH APPCH OF HIGH PRES. HOWEVER...THE RH/S WILL
EASILY GET BELOW 30PCT OVER ALL OF THE AREA. WINDS WILL BE THE
DECIDING FACTOR...AND TUESDAY MORNING SHIFT WILL CONSULT WITH FORESTRY
OFFICIALS ON ANY RED FLAG CONCERNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/MARTIN
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...MARTIN
AVIATION...LA CORTE/CERU
FIRE WEATHER...
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1058 AM CDT TUE APR 17 2012
.DISCUSSION...
A FEW SPRINKLES CONTINUE ACROSS THE EASTERN HALF OF THE FORECAST
AREA. THESE SHOWERS ARE QUICKLY DIMINISHING AND SHOULD COME TO AN
END WITHIN THE NEXT HOUR OR AS THEY LOSE THE WEAK MID LEVEL SUPPORT.
UPDATED THE POPS THIS MORNING TO FOLLOW THESE SHOWERS ALONG WITH
MORE EXTENSIVE CLOUD COVERAGE ACROSS OUR EAST. HRRR AND NAM STILL
DEVELOPING SOME MUCAPE AROUND 500 J/KG WITH EFFECTIVE SHEAR
INCREASING TO AROUND 35 KT IN THE EARLY TO LATE AFTERNOON MAINLY
EAST OF I29. THE NAM IS SLIGHTLY BRING IN SLIGHTLY BROADER AREA OF
ELEVATED INSTABILITY EXTENDING EAST OF THE JAMES RIVER INTO OUR MN
AND IA COUNTIES. SLIGHTLY ADJUSTED THUNDERSTORM CHANCES TO FOCUS ON
MN AND IA FOR THIS AFTERNOON CLOSER WHERE THE BEST ELEVATED
INSTABILITY AND SHEAR LIES. BETTER OVERALL POTENTIAL FOR
PRECIPITATION WILL DEVELOP THIS EVENING AND OVERNIGHT.
&&
.AVIATION.../FOR THE 19Z TAF ISSUANCE/
OVERALL VFR CONDITIONS EXPECTED THROUGH 18Z/WED. BREEZY SOUTH WINDS
THIS AFTERNOON WILL TURN WEST THEN NORTHWEST LATE TONIGHT EARLY
WEDNESDAY BEHIND A FRONT. SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE EAST OF I29 THIS AFTERNOON WITH A BETTER CHANCE ACROSS
THE FORECAST AREA FROM 00Z TO 06Z. BRIEF AND ISOLATED LOWERING OF
CEILINGS TO 3K FEET AND VISIBILITIES TO 3-5SM WILL BE POSSIBLE UNDER
THUNDERSTORMS.
&&
.PREV DISCUSSION...
TEMPS HAVE FALLEN INTO THE 29 TO 35 DEGREE RANGE THUS FAR
OVERNIGHT...DESPITE THE PRESENCE OF POCKETS OF MID/UPPER CLOUD COVER.
THE FROST ADVISORY...WHICH EXISTS GENERALLY NORTH OF CHAMBERLAIN TO
HAWARDEN TO SPENCER LINE...LOOKS TO BE IN GOOD SHAPE THROUGH 8 AM
CDT. RETURN FLOW BECOMES REESTABLISHED TODAY...AND H85 TEMPERATURES
MODERATE TO BETWEEN +10C /SWRN MN/ AND +15C /SCNTRL SD/ ACROSS THE
FORECAST AREA. PROGGED MIXING YIELDS HIGHS IN THE MID 60S TO LOWER
70S. WEAK ELEVATED INSTABILITY DEVELOPS THIS AFTERNOON ON THE NOSE
OF THE INCREASING LLJ...SO COULD SEE SOME WIDELY SCT THUNDERSTORMS
OVER NWRN IA AND ADJACENT AREAS IN MN/SD/NE AFTER 21Z. PRECIPITATION
CHANCES THEN INCREASE DURING THE EVENING HOURS ACROSS THE FORECAST
AREA AS A SHORTWAVE TROUGH APPROACHES FROM THE WEST AND IS ALSO
REFLECTED IN THE LLVL PRESSURE FIELDS. THE SURFACE TROUGH WILL BE
DRAPED ACROSS THE DAKOTAS/NEBRASKA DURING THE PEAK OF DAYTIME
HEATING. ALTHOUGH MOISTURE RETURN WILL BE MODEST AT THAT
POINT...COULD STILL SEE A FEW STRONGER STORMS LATE THIS AFTERNOON
AND EVENING GIVEN THE SHEAR PROFILE WITH THE ADVANCING TROUGH.
SHOWERS AND THUNDERSTORM COVERAGE SHOULD INCREASE OVERNIGHT...AS A
DECENT AREA OF FORCING PASSES OVER THE AREA. SAID SHORTWAVE TROUGH
MARCHES ACROSS THE REGION AT A FAIRLY STEADY PACE...SO PRECIPITATION
IS EXPECTED TO HAVE ENDED BY DAYBREAK WEDNESDAY. LOW TEMPS WEDNESDAY
MORNING SHOULD BE ELEVATED IN THE LOWER 40S-50S RANGE GIVEN THE
EXTENSIVE CLOUD COVER. NOT A BIG SURGE OF COLD AIR BEHIND THIS WAVE
GIVEN THE CONTINUANCE OF THE SEMI-ZONAL FLOW REGIME...SO WEDNESDAY
HIGHS SHOULD BE ABLE TO RECOVER INTO THE LOW/MID 60S AND 70S. THE
NEXT SHORTWAVE WILL FOLLOW APPROXIMATELY 24 HOURS LATER...THIS TIME
WITH A SLIGHTLY MORE IMPRESSIVE ACCOMPANYING PV ANOMALY. THIS
FEATURE KICKS ACROSS THE REGION ON WEDNESDAY NIGHT AND
THURSDAY...WITH THE ATTENDANT SFC TROUGH NOSING INTO THE SOUTHERN
CWA. ALTHOUGH THERE ARE TEMPORAL/SPATIAL DIFFERENCES BETWEEN THE
MODEL SOLUTIONS...AM CONFIDENT ENOUGH TO GO WITH HIGH LIKELY POPS /70
PERCENT/ BETWEEN 06Z THURSDAY AND 00Z FRIDAY. HAVE LEANED TOWARD THE
LESS AGGRESSIVE GFS/ECMWF SOLUTIONS OVER THE FASTER NAM.
HIGH TEMPS ON FRIDAY SHOULD BE REDUCED BACK INTO THE 50S AS WEAK
TROUGHING PERSISTS...BUT THE PREVIOUSLY ADVERTISED WARM-UP LOOKS TO
BE ON TRACK AS RIDGING BUILDS INTO THE AREA INTO NEXT WEEK. AFTER THE
POSSIBILITY OF A FEW SHOWERS LATE FRIDAY INTO SATURDAY AS THE
TRANSITION OCCURS...DRY WEATHER IS EXPECTED ON SUNDAY AND MONDAY.
ADDITIONALLY...HIGHS WILL MODERATE FROM THE MID 50S/60S ON
SATURDAY...TO THE UPPER 60S/70S ON MONDAY AND TUESDAY...WHICH IS 10
TO 15 DEGREES ABOVE NORMAL FOR LATE APRIL.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
312 PM CDT TUE APR 17 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
312 PM CDT TUE APR 17 2012
MAIN FORECAST CONCERN IS ON THE MULTITUDE OF PRECIPITATION CHANCES
THROUGHOUT THE SHORT TERM...ESPECIALLY THURSDAY NIGHT AND FRIDAY.
P-TYPE ALSO A CONCERN FOR THURSDAY NIGHT AND FRIDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED NEARLY ZONAL FLOW ACROSS MUCH OF THE COUNTRY WITH PERHAPS
SOME WEAK RIDGING OVER IDAHO AND MINNESOTA. IN-BETWEEN THESE TWO
WEAK RIDGES...A FAIRLY POTENT SHORTWAVE TROUGH IS NOTED OVER CENTRAL
MONTANA. DOWNSTREAM OF THIS SHORTWAVE...MID CLOUDS HAVE BEEN
SPREADING EAST ACROSS THE DAKOTAS AND MINNESOTA. NO PRECIPITATION AS
OF YET...DUE TO DRY AIR SEEN ON THE 12Z BIS SOUNDING BELOW 600MB.
HOWEVER...SOUTHERLY 925MB WINDS OF 10 TO 20 KT IS SLOWLY BRINGING
MORE LOW LEVEL MOISTURE NORTHWARD. DEWPOINTS HAVE CLIMBED INTO THE
MID 40S OVER MUCH OF EASTERN SOUTH DAKOTA. FARTHER SOUTHEAST...
ISENTROPIC LIFT ON THE 295K SURFACE HAS RESULTED IN SCATTERED MID-
CLOUD DEVELOPMENT OVER IOWA AND SOUTHERN MINNESOTA. MOSTLY SUNNY
SKIES OVER THE FORECAST AREA COMBINED WITH 850MB TEMPS SLOWLY
RISING...WHICH WERE 0 TO -7C PER 12Z RAOB ANALYSIS...HAS HELPED
PUSH TEMPERATURES INTO THE 50S TO LOW 60S.
TONIGHT AND WEDNESDAY...FOCUS IS ON THE POTENT SHORTWAVE TROUGH.
MODELS REMAIN REMARKABLY CONSISTENT ON THIS TROUGH TRACKING
EAST...REACHING WESTERN UPPER MICHIGAN BY 18Z WEDNESDAY. AS THE
TROUGH APPROACHES TONIGHT...A STRONG SURGE OF 850MB MOISTURE
TRANSPORT COMES UP AHEAD OF IT. PRECIPITABLE WATER CLIMBS TO 0.75 TO
1 INCH BY 12Z WEDNESDAY...A JUMP FROM 0.3 TO 0.6 INCHES NOW. THIS
SURGE OF MOISTURE COMBINED WITH DPVA/HEIGHT FALLS ASSOCIATED WITH
THE TROUGH (30-70 METERS IN 12 HOURS) WILL LIKELY LEAD TO THE
DEVELOPMENT OF A NARROW WARM CONVEYOR BELT OF SHOWERS. MUCAPE VALUES
ARE LESS THAN 300 J/KG...WHICH IS A THIN CAPE TOO ON SOUNDINGS...SO
ANTICIPATE AT MOST JUST SOME SCATTERED EMBEDDED THUNDERSTORMS. GIVEN
VERY PERSISTENT SIGNAL ON PRECIPITATION TONIGHT INTO WEDNESDAY
MORNING...HAVE RAISED PRECIPITATION CHANCES TO 100...WITH THE PEAK
TIME OF PRECIPITATION EXPECTED BETWEEN 09-15Z WEDNESDAY. DURING THE
LATE MORNING AND AFTERNOON...A DRY SLOT IS PROGGED TO COME IN BEHIND
THE SHORTWAVE TROUGH...WHICH WHEN COMBINED WITH THE SURFACE FRONT
PUSHING EAST SHOULD END PRECIPITATION OVER THE NORTHWEST HALF OF THE
AREA. OVER THE SOUTHEAST HALF...THE COLD FRONT ENDS UP SLOWING DOWN
AS THE TROUGH PULLS AWAY. COULD SEE ADDITIONAL DIURNAL DEVELOPMENT
OF SHOWERS AND STORMS ALONG THIS FRONT AS CAPE JUMPS TO AROUND 500
J/KG. THEREFORE...CHANCES OF PRECIPITATION REMAIN IN THE SOUTHEAST
HALF IN THE AFTERNOON...MAINLY IN THE 40-50 RANGE. WITH INCREASING
WARM ADVECTION TONIGHT...LOWS LIKELY TO OCCUR IN THE EVENING WITH A
SLOW RISE THEREAFTER. NEEDLESS TO SAY...A MUCH WARMER NIGHT
TONIGHT. ON WEDNESDAY...A SURGE OF 6-8C 850MB TEMPS COMING UP
WITH THE TROUGH COMBINED WITH SUN SHOULD ALLOW FOR HIGHS IN THE
60S TO POSSIBLY LOW 70S.
WEDNESDAY NIGHT AND THURSDAY...FOLLOWED THE PREVIOUS FORECAST IN
MAINTAINING A 20 PERCENT CHANCE DOWN IN THE FAR SOUTHEAST SECTION OF
THE FORECAST AREA WEDNESDAY EVENING...TO ACCOUNT FOR THE SLOW MOVING
COLD FRONT AND ANY LINGERING SHOWERS/STORMS ON IT. A SURFACE RIDGE
OF HIGH PRESSURE BUILDS IN ELSEWHERE BEHIND THE FRONT...LEADING TO
DRY CONDITIONS FOR THE EVENING. ATTENTION THEN FOCUSES ON A
SHORTWAVE TROUGH JUST OFF THE PACIFIC NORTHWEST COAST. ON WEDNESDAY
NIGHT...THIS TROUGH ALONG WITH A FEW OTHERS COMING OFF THE PACIFIC
HELP DEVELOP A BROAD TROUGH ALONG THE LEE SIDE OF THE ROCKIES. IN
RESPONSE...MOISTURE TRANSPORT...ISENTROPIC LIFT AND LOW TO MID LEVEL
FRONTOGENESIS INCREASES DOWNSTREAM...LEADING TO PRECIPITATION
DEVELOPMENT. PRIOR TO 12Z THURSDAY...MUCH OF THIS PRECIPITATION
LOOKS TO BE CONFINED TO THE DAKOTAS INTO IOWA. DID MAINTAIN THE
20-30 PERCENT CHANCES MAINLY WEST OF THE RIVER LATE WEDNESDAY NIGHT
IN CASE THE PRECIPITATION SPREADS IN QUICKER. MUCH BETTER SHOT FOR
PRECIPITATION EXISTS ON THURSDAY AS THE LOW TO MID LEVEL
FRONTOGENESIS TIGHTENS THROUGH THE DAY OVER THE AREA. IN
ADDITION...THERE ARE INDICATIONS THAT IN THE AFTERNOON AN UPPER
LEVEL JET STREAK DEVELOPING OVER NORTHERN WISCONSIN. THIS WOULD BE
VERY FAVORABLE FOR PRECIPITATION. LASTLY...LOW LEVEL MOISTURE
TRANSPORT NORTH OF A DEVELOPING WARM FRONT NEAR US-20 SHOULD BRING
SOME INSTABILITY INTO THE FRONTOGENESIS ZONE. THEREFORE...HAVE
MAINTAINED THE THUNDER CHANCES. TEMPERATURES DEFINITELY COOLER
DURING THIS TIME PERIOD...ESPECIALLY NORTH OF I-90 WHERE A NORTHEAST
FLOW WILL HELP TO FEED COOL AIR IN. WILL HAVE TO WATCH TEMPERATURES
WHEN THE PRECIPITATION STARTS...AS THEY MAY FALL DUE TO THE FEED OF
30S DEWPOINTS INTO THE AREA. HOWEVER...DID NOT INCLUDE ANY
NON-DIURNAL TREND GIVEN THE 17.12Z ECMWF/CANADIAN/UKMET WHICH IS
FARTHER NORTH WITH THE WARMER AIR.
THURSDAY NIGHT AND FRIDAY...FOCUS CONTINUES ON THE STRENGTHENING
FRONTOGENESIS ZONE OVER THE AREA FROM THURSDAY AFTERNOON. ALL MODELS
ARE WELL AGREED UPON THAT THE TROUGHING OVER THE ROCKIES WILL DIG
DOWN INTO THE CENTRAL PLAINS THURSDAY NIGHT. HOWEVER...THE 17.12Z
GFS/NAM ARE MORE PROGRESSIVE WITH EXITING THE FRONTOGENESIS ZONE TO
THE EAST AND SOUTHEAST THAN THE 17.12Z ECMWF/UKMET/CANADIAN. AM
CONCERNED THE GFS/NAM ARE TOO PROGRESSIVE. IF SO...THE NON-NCEP
MODEL GROUP WOULD YIELD A LOT MORE PRECIPITATION THURSDAY NIGHT...
ESPECIALLY FROM NORTHEAST IOWA TO GREEN BAY. THEY SHOW ANYWHERE FROM
1 TO 2 INCHES OF RAINFALL. THE NORTH EDGE OF SOME OF THIS...SAY IN
CENTRAL AND NORTHERN WISCONSIN...IS LIKELY TO MIX WITH OR CHANGE
OVER TO SNOW AS CONTINUED DRY/COOL AIR FEED AND DYNAMIC COOLING HELP
LOWER THE THERMODYNAMIC PROFILE TEMPERATURES. TOO EARLY TO SAY HOW
MUCH SNOW SAY COULD ACCUMULATE IN TAYLOR COUNTY...WHICH IS MOST
LIKELY TO SEE SNOW...BUT SOMETHING TO KEEP AN EYE ON. IN ANY
EVENT...HAVE LEANED THE FORECAST FOR THIS PERIOD TOWARDS THE
ECMWF/UKMET/CANADIAN...WHICH RESULTS IN AN INCREASE IN PRECIPITATION
CHANCES AND QPF FOR BOTH THURSDAY NIGHT AND FRIDAY. FURTHER
INCREASES MAY BE NECESSARY...ESPECIALLY IF THE GFS/NAM COME AROUND.
FOR TEMPERATURES...TOOK A BLEND OF GUIDANCE FOR NOW UNTIL MODELS CAN
SETTLE DOWN.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
312 PM CDT TUE APR 17 2012
17.12Z ECMWF/GFS AND GFS ENSEMBLES ARE IN GOOD AGREEMENT SUGGESTING
THAT THE TROUGH DIGGING DOWN THROUGH THE CENTRAL PLAINS THURSDAY
NIGHT AND FRIDAY ENDS UP CLOSING OFF NEAR THE GULF COAST FOR
SATURDAY. THIS IS AN IMPORTANT CHANGE AS NOW THE TROUGHING OVER THE
FORECAST AREA FOR THE WEEKEND IS NOT NEARLY AS DEEP. COMPARE THIS TO
THE 17.12Z CANADIAN WHICH DEVELOPS A FULL-BLOWN EASTERN TROUGH THAT
LOOKS VERY COLD. THIS MODEL SCENARIO APPEARS TO BE AN OUTLIER AND
WAS DISCOUNTED. FOLLOWING THE MAIN MODEL GROUP...MUCH OF FRIDAY
NIGHT THROUGH MONDAY SHOULD BE DRY WITH THE AREA DOMINATED BY
SURFACE HIGH PRESSURE IN THE WAKE OF FRIDAYS FRONTOGENESIS ZONE.
MAY HAVE TO DEAL WITH A LITTLE LIGHT PRECIP SATURDAY NIGHT...
ASSOCIATED WITH A SHORTWAVE COMING DOWN THROUGH THE NORTHWEST
FLOW. ALSO...WITH WITH THE RIDGE BUILDING FRIDAY NIGHT...LOCATIONS
ALONG AND NORTH OF I-94 MAY HAVE TO CONTEND WITH ANOTHER FREEZE.
RIDGING THAT DEVELOPS DURING THE WEEKEND OVER THE WESTERN U.S.
IS FORECAST TO PUSH EASTWARD MONDAY INTO TUESDAY...DUE TO A POTENT
SHORTWAVE TROUGH DROPPING INTO THE PACIFIC NORTHWEST. THE RIDGING
WILL HELP TO PUSH WARMER AIR INTO THE AREA...WITH TEMPERATURES
LIKELY CLIMBING ABOVE NORMAL. CONVECTION COULD OCCUR LATE TUESDAY
AS A WARM FRONT / LOW PRESSURE SYSTEM OVER THE NORTHERN PLAINS
MOVES INTO OUR REGION.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1237 PM CDT TUE APR 17 2012
HIGH PRESSURE WILL MOVE EAST OF THE REGION THIS AFTERNOON AS LOW
PRESSURE DEEPENS OVER THE DAKOTAS. THE LOW IS EXPECTED TO MOVE INTO
NORTHERN MINNESOTA THIS EVENING. THE PRESSURE GRADIENT WILL TIGHTEN
OVER THE AREA...WITH SOUTH WINDS INCREASING INTO THE 15 TO 20 KT
RANGE THIS EVENING. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE
AREA LATE TONIGHT INTO EARLY WEDNESDAY MORNING BRINGING SHOWERS
AND PERHAPS AN ISOLATED THUNDERSTORM OR TWO TO THE TAF SITES. PLAN
ON MVFR CONDITIONS TONIGHT AS LOW LEVEL MOISTURE STREAMS INTO THE
REGION AHEAD OF THE FRONT...WITH CEILINGS LOWERING INTO THE 2-3KFT
RANGE. WINDS WILL SWITCH TO THE SOUTHWEST BY MID WEDNESDAY MORNING
AS THE FRONT PASSES THROUGH...SWITCHING TO THE WEST BEHIND THE
FRONT. LOOK FOR CEILINGS TO IMPROVE TO VFR BY LATE WEDNESDAY
MORNING...IMPROVING TO AROUND 4KFT. FORECAST SOUNDINGS AT KLSE
ARE SHOWING MORE INSTABILITY OVER THE PREVIOUS GUIDANCE.
THUNDERSTORMS MAY NEED TO BE INCLUDED AT THE KLSE TAF STARTING AT
18Z IF THE INCREASE IN INSTABILITY MATERIALIZES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
312 PM CDT TUE APR 17 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 PM CDT MON APR 16 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
319 PM CDT MON APR 16 2012
MAIN FORECAST CONCERNS ARE ON FREEZE TONIGHT AND PRECIPITATION
CHANCES FOR TUESDAY NIGHT...WEDNESDAY AND AGAIN THURSDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S....TROUGHING FROM ONTARIO INTO
TEXAS AND RIDGING ALONG THE EAST COAST OF THE U.S.. WITHIN THE
TROUGHING...A POTENT SHORTWAVE TROUGH WAS OVER UPPER MICHIGAN WHICH
HAS BEEN RESPONSIBLE FOR THE WINDY CONDITIONS LATELY...WHILE ANOTHER
SHORTWAVE WAS NEAR SIOUX FALLS SOUTH DAKOTA. THIS LATTER SHORTWAVE
WAS NOT DOING MUCH PRECIPITATION WISE...BUT THERE IS A DEFINITE BAND
OF LOW TO MID LEVEL CLOUDS COVERING MUCH OF THE DAKOTAS INTO
SOUTHWEST MINNESOTA. 12Z BIS SOUNDING WAS NEARLY SATURATED FROM 925
TO 700MB...SO THE SHORTWAVE DOES APPEAR TO BE SPREADING AT LEAST
CLOUDS EASTWARD. AHEAD OF THESE CLOUDS AND IN THE WAKE OF THE POTENT
TROUGH...THERE IS SOME CLEARING DROPPING DOWN THROUGH NORTHERN AND
CENTRAL MINNESOTA. WINDS ARE SLOWLY DIMINISHING ACROSS THE AREA DUE
TO A WEAKENING PRESSURE GRADIENT. SURFACE PRESSURE ANALYSIS SHOWED A
997MB LOW WAS LOCATED OVER THE EASTERN UPPER PENINSULA WHILE A RIDGE
OF HIGH PRESSURE WAS OVER THE DAKOTAS. THE WINDY NORTHWEST WINDS
HAVE DROPPED 850MB TEMPS DOWN TO -4 TO -8C OVER THE FORECAST AREA
PER RUC ANALYSIS...AND -10 TO -12C OVER NORTHERN WISCONSIN. THIS
COLD AIR LED TO SOME STRAIGHT SNOW OR RAIN/SNOW MIX OVER NORTHERN
PORTIONS OF THE FORECAST AREA THIS MORNING. 850MB TEMPS NOT MUCH
WARMER OVER THE DAKOTAS EITHER...-2 TO -6C...CONFIRMED TOO BY 12Z
RAOBS.
TONIGHT AND TUESDAY...UPPER LEVEL FLOW IS PROGGED TO BECOME MORE
ZONAL DURING THIS PERIOD AS A SHORTWAVE OFF THE PACIFIC NORTHWEST
COAST PLOWS INLAND ACROSS THE NORTHERN ROCKIES. FOR OUR AREA...WE
WILL HAVE A FEW SHORTWAVES MOVE THROUGH...THE FIRST OF WHICH IS THE
ONE NEAR SIOUX FALLS CROSSING THIS EVENING...THEN ANOTHER MUCH
WEAKER ONE SEEN ON WATER VAPOR OVER EASTERN MONTANA WHICH COMES
THROUGH TUESDAY MORNING. AGAIN...NOT ANTICIPATING ANY PRECIPITATION
WITH EITHER SHORTWAVE BECAUSE OF A LACK OF BOTH DYNAMICAL AND
ISENTROPIC LIFT. THEY WILL...HOWEVER...BRING AN INCREASE OF LOW TO
MID LEVEL STRATUS. SO AFTER WHAT COULD BE A BRIEF PERIOD OF CLEARING
THIS EVENING...MAINLY NORTH OF I-94 ASSOCIATED WITH THAT CLEARING
DROPPING DOWN THROUGH CENTRAL MINNESOTA...EXPECTING SKIES TO AT
LEAST TURN MOSTLY CLOUDY. LIKELY THE STRATUS SHOULD CLEAR OUT IN THE
WAKE OF THE SECOND SHORTWAVE...BUT THIS APPEARS BRIEF AS WELL.
LOOKING AT TUESDAY AFTERNOON...290-300 K ISENTROPIC LIFT REALLY
INCREASES DOWNSTREAM OF THAT SHORTWAVE COMING INTO THE ROCKIES...
RESULTING IN MORE MID LEVEL STRATUS. LIFT DOES NOT LOOK STRONG
ENOUGH TO PRODUCE PRECIPITATION...THOUGH. ALL OF THESE CLOUD
TRANSITIONS MAKE THE TEMPERATURE FORECAST DIFFICULT. IF IT WERE
CLEAR TONIGHT...THE SURFACE RIDGE MOVING IN AND HAVING 850MB TEMPS
IN THE 0 TO -6C RANGE IN PLACE WOULD BE VERY FAVORABLE FOR
TEMPERATURES TO PLUMMET WELL BELOW FREEZING. WITH THE CLOUDS MOVING
THROUGH TONIGHT...GENERALLY FOLLOWED CLOSE TO A BLEND OF THE 16.12Z
NAM12/16.09Z SREF MEAN. THE LOWS PROMPT THE NEED FOR A FREEZE
WARNING ALONG/NORTH OF I-94. LOWS MAY DIP TO FREEZING
ELSEWHERE...SUCH AS LA CROSSE...BUT CONFIDENCE IS NOT HIGH ENOUGH TO
ISSUE FREEZE WARNING DUE TO THE CLOUDS. FOR TUESDAY...RETURN FLOW
DOES HELP TO BOOST 850MB TEMPS UP TO 2-6C BY 00Z WEDNESDAY...BUT
TEMPERATURES WILL BE HELD BACK SOMEWHAT DUE TO THE CLOUDS. FOLLOWED
GENERALLY A BLEND OF GUIDANCE FOR HIGHS.
TUESDAY NIGHT AND WEDNESDAY...FOCUS IS ON THAT SHORTWAVE COMING OUT
OF THE ROCKIES. VERY GOOD MODEL AGREEMENT EXISTS THAT AS THE
SHORTWAVE CROSSES THE DAKOTAS AND LIFTS INTO FAR NORTHERN WISCONSIN
WEDNESDAY MORNING...IT WILL DEEPEN. IN RESPONSE TO THIS DEEPENING...
A STRONG SURGE OF SOUTHWEST 850MB MOISTURE TRANSPORT/ISENTROPIC LIFT
ON THE 290-295K SURFACE COMES ACROSS THE AREA TUESDAY EVENING.
SHOULD SEE SOME SHOWERS FALL IN THE EVENING. THERE IS SOME WEAK
CAPE...LESS THAN 200 J/KG...ENOUGH TO WARRANT A THUNDER MENTION.
AFTER MIDNIGHT INTO WEDNESDAY MORNING...THE COMBINATION OF HEIGHT
FALLS ALOFT WITH THE APPROACHING SHORTWAVE AND A PERSISTENT FLOW OF
850MB MOISTURE TRANSPORT SHOULD LEAD TO THE DEVELOPMENT OF A WARM
CONVEYOR BELT OF SHOWERS AND EMBEDDED THUNDERSTORMS. GIVEN DECENT
COVERAGE OF PRECIPITATION DEVELOPMENT...CAPE SHOULD STAY LIMITED AT
LESS THAN 500 J/KG...LIMITING ANY CHANCE FOR SEVERE WEATHER. THIS
WARM CONVEYOR BELT WILL TRACK WEST TO EAST ACROSS THE AREA THROUGH
WEDNESDAY MORNING. GIVEN GOOD MODEL CONSENSUS FOR PRECIPITATION...
HAVE RAISED PRECIPITATION CHANCES UP TO 80 PERCENT. A DRY SLOT THEN
ENTERS THE PICTURE FOR LATE WEDNESDAY MORNING INTO THE AFTERNOON...
PUNCHING IN FROM THE WEST IN THE WAKE OF THE SHORTWAVE TROUGH
LIFTING OFF TO THE NORTHEAST. THIS DRY SLOT SHOULD END PRECIPITATION
AND LIKELY RESULT IN A DECREASE IN CLOUDS. MUCH WARMER CONDITIONS
ANTICIPATED TUESDAY NIGHT WITH LOWS IN THE EVENING...THEN CLIMBING
SLIGHTLY AFTER MIDNIGHT WITH THE MOISTURE TRANSPORT SURGE. WARMER
850MB TEMPS OF 4-8C ON WEDNESDAY...PLUS SUN...WILL ALLOW FOR HIGHS
IN THE 60S TO EVEN 70.
WEDNESDAY NIGHT AND THURSDAY...THIS PERIOD FOCUS IS ON A COLLECTIONS
OF SHORTWAVES PROGGED TO MOVE INTO THE NORTHERN ROCKIES LATE
WEDNESDAY. HEIGHT FALLS DOWNSTREAM OF THESE SHORTWAVES HELP DEVELOP
A SURFACE LOW IN SOUTHEAST COLORADO. GOOD MODEL CONSENSUS EXISTS
THAT THE COLLECTION OF SHORTWAVES WILL DIG DOWN INTO THE CENTRAL
PLAINS WEDNESDAY NIGHT...LEADING TO A SHIELD OF DPVA AND DEFORMATION
FORCED PRECIPITATION DOWNSTREAM. AT THIS TIME IT APPEARS ANY
PRECIPITATION SHOULD HOLD OFF UNTIL THURSDAY. THERE ARE SOME ISSUES
THAT REMAIN FOR THURSDAY...THOUGH. ALTHOUGH GREAT MODEL AGREEMENT
EXISTS BETWEEN THE 16.12Z GFS/NAM/ECMWF/CANADIAN THAT MUCH OF THE
AREA SEES THAT DPVA AND DEFORMATION PRECIPITATION...THE
ECMWF/CANADIAN REMAIN FARTHER NORTH WITH THE ASSOCIATED SURFACE
SYSTEM. IF THESE HOLD TRUE...THUNDER CHANCES WOULD BE REQUIRED FOR
AT LEAST LOCATIONS SOUTH OF I-90. FOR NOW HAVE KEPT THUNDER OUT
GIVEN THAT IT RECENTLY WAS AND THE PERSISTENCE FOR MORE SOUTHERN
SOLUTIONS...BUT THIS WILL NEED TO BE WATCHED. CERTAINLY POTENTIAL
HERE FOR SOME DECENT QPE VALUES TOO...WITH CURRENT FORECAST QPF
ANYWHERE FROM 0.25 TO 0.75 INCHES.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
319 PM CDT MON APR 16 2012
GOOD AGREEMENT REMAINS AMONGST 16.12Z GFS/ECMWF/CANADIAN AND GFS
ENSEMBLES ON SHOWING MAJOR AMPLIFICATION WITH THE UPPER FLOW DURING
THE LONG TERM PERIOD. RIDGING IN THE WESTERN U.S. DEVELOPS THURSDAY
NIGHT THROUGH SATURDAY WHILE A POTENT SHORTWAVE RIDES DOWN THE
RIDGE...FORMING A DEEP TROUGH OVER THE SOUTHEASTERN U.S. BY SATURDAY
NIGHT. BY MONDAY...A BLOCKED UP PATTERN IS FORECAST WITH STRONG
RIDGING OVER THE WESTERN U.S. AND A WIDE/DEEP CUT-OFF UPPER LOW OVER
THE EASTERN U.S.. THIS MEANS A COOL PATTERN FOR THE FORECAST
AREA...THOUGH OVERALL RELATIVELY DRY. REALLY ONLY PRECIPITATION TO
SPEAK OF IS THURSDAY NIGHT...ASSOCIATED WITH DEFORMATION AND DPVA
INDUCED RAIN FROM THURSDAY SLOWLY EXITING. ENOUGH COLD AIR DOES WRAP
DOWN INTO THE AREA FOR A MIX OR CHANGE OVER TO SNOW...THOUGH IT IS
CONCEIVABLE THE PRECIPITATION ENDS BEFORE THE COLDER AIR ARRIVES.
ALSO HAVE A SLIGHT CHANCE OF RAIN SHOWERS IN FOR SATURDAY NIGHT
WHERE THERE ARE SUGGESTIONS OF A SHORTWAVE DROPPING DOWN INTO THE
EASTERN TROUGH. ONLY KEPT AT 20 PERCENT GIVEN VERY FEW MODELS HAVE
THIS PRECIPITATION. IN FACT...LATER FORECASTS MAY BE ABLE TO PULL
THIS IF ALL MODELS TREND TOWARD THE ECMWF/GFS. OTHERWISE...
TEMPERATURES ARE THE STORY WHICH AGAIN LOOK TO HOLD BELOW NORMAL. IN
ADDITION...COULD BE DEALING WITH FREEZE WARNINGS FOR FRIDAY NIGHT
AND POSSIBLY SATURDAY NIGHT AS WELL...IF THE PRECIPITATION DOES NOT
MATERIALIZE. BEST CHANCE FOR FREEZE IS AGAIN ALONG AND NORTH OF
I-94. PERHAPS TOWARDS MONDAY WE WILL BE ABLE TO CLIMB BACK TO NEAR
OR ABOVE NORMAL WITH HINTS OF THE UPPER RIDGE TRYING TO BUILD
TOWARDS THE AREA.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1151 PM CDT MON APR 16 2012
A MID TO HIGH DECK OF VFR CEILINGS WERE FOUND AT THE TAF SITES AT
05Z. SATELLITE TRENDS WERE SHOWING A GRADUAL DECREASE IN THE
CLOUDS ACROSS THE AREA AND MODEL SOUNDINGS ALSO INDICATING THIS
TREND. THUS DID SCATTERED OUT THE CEILINGS BETWEEN 06Z-09Z AT BOTH
SITES. VFR CONDITIONS THEN WILL PREVAIL THROUGH THE REMAINDER OF
THE FORECAST PERIOD. VFR CEILINGS LOOK TO RETURN LATER TODAY AHEAD
OF THE NEXT SYSTEM PUSHING THROUGH THE PLAINS. CEILINGS WILL
GRADUALLY LOWER TO AROUND 4K FEET AT KRST BY 04Z...WITH THE
POSSIBILITY OF A FEW SHOWERS FROM 04Z-06Z AT KRST AND DID INTRODUCED
VCSH IN THIS TIME FRAME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 PM CDT MON APR 16 2012
WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT TUESDAY FOR WIZ017-029-034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
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 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
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 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 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
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 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 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 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
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...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 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 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 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 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 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 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 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...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
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
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 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 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.
&&
$$