Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/01/12
AREA FORECAST DISCUSSION
NWS ALBANY NY
102 AM EST MON JAN 30 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING SNOW SHOWERS AND
SQUALLS TONIGHT...MAINLY FOR WESTERN AND NORTHERN PARTS OF THE
REGION. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON
MONDAY BEFORE BEING FOLLOWED BY A WARM FRONT...WHICH WILL BRING
ANOTHER ROUND OF SNOW TO THE AREA FOR MONDAY NIGHT INTO TUESDAY
MORNING.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1245 AM...POTENT BUT COMPACT UPPER LEVEL DISTURBANCE
CLEARLY EVIDENT OF WATER VAPOR IMAGERY WITH A DISTINCT SWIRL SEEN
WITH COMMA-HEAD MOVING INTO EAST CENTRAL NY. SNOW SQUALL ACTIVITY
NOT AS WIDESPREAD AS EARLY ACROSS WESTERN/CENTRAL NY. BROKEN LINES
OF SNOW SHOWERS WITH A FEW BRIEF INTENSE SQUALLS WILL CONTINUE TO
BE POSSIBLE THROUGH THE REST OF THE NIGHT...MAINLY ACROSS THE
HIGHER TERRAIN WEST OF THE CAPITAL REGION. WILL NOT MAKE ANY
CHANGES TO SNOWFALL FORECAST OR HEADLINES AT THIS TIME AS REPORTS
ARE SCARCE THIS TIME OF DAY. ALSO UPDATED HOURLY GRIDS TO REFLECT
CURRENT OBS AND TRENDS.
PREVIOUS NEAR TERM DISCUSSIONS...
AS OF 1000 PM...INTENSE NORTH-SOUTH SNOW SQUALL THAT WAS MOVING
ACROSS WESTERN AND CENTRAL PA/NY HAD WEAKENED AND BROKEN UP
CONSIDERABLY. RADAR STILL SHOWS SOME SNOW SQUALLS PRODUCING HEAVY
SNOW...BUT MOST OF THESE WILL MOVE ACROSS HERKIMER AND HAMILTON
COUNTIES WHERE WINTER WEATHER ADVISORIES ARE ALREADY UP. ELSEWHERE
THE SNOW SHOWERS WILL CONTINUE TO DECREASE IN COVERAGE AS THEY MOVE
EAST. IN GENERAL HAVE RAISED POPS TO LIKELY ACROSS THE EASTERN
CATSKILLS AND NORTHERN BERKSHIRE COUNTY...WITH LIKELY POPS OR HIGHER
ALREADY IN THE GRIDS IN AREAS FURTHER NORTH. FROM THE CAPITAL
DISTRICT TO THE MID HUDSON VALLEY AND SOUTHERN BERKSHIRE COUNTY AND
LITCHFIELD COUNTY...HAVE ALSO RAISED POPS IN THESE AREAS...BUT THE
FORECAST REMAINS IN THE CHANCE CATEGORY. REST OF THE PREVIOUS
FORECAST GENERALLY UNCHANGED.
AS OF 648 PM EST...HAVE UPDATED T/TD TO ACCOUNT FOR LATEST
OBSERVATIONS AND TRENDS. CURRENT FORECAST MIN TEMPS APPEAR ON
TRACK WITH 20S FOR MOST AREAS /SOME TEENS ACROSS THE SRN ADKS/.
LATEST RADAR RETURNS SHOW SOME MODERATE SNOWFALL DUE TO SOME LAKE
MOISTURE UPSLOPING THE HIGH TERRAIN AFFECTING THE WESTERN
ADKS...MAINLY TO THE NORTH OF OLD FORGE AND INLET. THIS LOOKS TO
CONTINUE OVER THE NEXT SEVERAL HOURS...WITH A FEW INCHES POSSIBLE.
THIS ACTIVITY WILL WANE SOMEWHAT AS THE FLOW SHIFTS AHEAD OF AN
APPROACHING SHORTWAVE AND ASSOCIATED SURFACE BOUNDARY.
THE 20Z 3KM HRRR GUIDANCE STILL DEPICTS A FAST MOVING LINE OF SNOW
SHOWERS/SQUALLS ASSOCIATED WITH THE AFOREMENTIONED COLD FRONTAL
BOUNDARY HEADING TOWARDS OUR AREA AROUND MIDNIGHT. MODEL GUIDANCE
SUGGESTS THAT THIS ACTIVITY WON/T BE QUITE AS STRONG AS IT WILL BE
EARLIER IN THE EVENING ACROSS WESTERN NY/WESTERN AND CENTRAL
PA...BUT IT SHOULD STILL BE ENOUGH TO BRING ADDITIONAL ACCUMULATION
AND PROVIDE LOW VISIBILITY WITHIN GUSTY WINDS. THE 18Z NAM STILL
DEPICTS SHOWALTER VALUES NEAR OR JUST BELOW ZERO FOR WESTERN PARTS
OF THE AREA. LTG DETECTION HAS ALREADY NOTED SOME LTG ACROSS
WESTERN PA AND WESTERN NY...SO CANNOT TOTALLY RULE OUT SOME LTG
WITHIN THE HEAVIEST SQUALLS. HOWEVER...DO NOT FEEL CONFIDENT THIS
WILL BE WIDESPREAD ENOUGH TO INCLUDE IN THE GRIDS...BUT IT
CERTAINLY COULD OCCUR IN A FEW ISOLD SPOTS. THE BEST CHANCE OF
SEEING THE SNOW SQUALLS WILL BE ACROSS THE MOHAWK VALLEY/SRN
ADIRONDACKS AND EVENTUALLY THE LAKE GEORGE SARATOGA REGION...WHERE
WE CURRENTLY HAVE THE HIGHEST POPS /LIKELY TO CATEGORICAL/. THE
ACTIVITY LOOKS TO WEAKEN ENOUGH FOR SNOW SHOWERS TO BE RATHER SCT
ONCE ACTIVITY GETS TOWARDS THE CAPITAL REGION BY AROUND 06Z TO
07Z. WHILE A COATING OF SNOWFALL IS POSSIBLE...THE LINE LOOKS TO
BREAK ENOUGH FOR IT TO BE HIT OR MISS ACROSS FOR THE CAPITAL REGION.
FURTHER SOUTH...DOWNSLOPING OFF THE CATSKILLS SHOULD KEEP ANY
ACTIVITY FAIRLY ISOLD FOR THE MID HUDSON VALLEY AND NW
CT...ALTHOUGH UPSLOPE FLOW COULD ALLOW FOR A LITTLE BETTER
COVERAGE ACROSS THE TACONICS/BERKSHIRES/SOUTHERN GREENS...WHERE A
LIGHT ACCUMULATION IS POSSIBLE.
LATE TONIGHT AND MONDAY...IN THE WAKE OF THE CLIPPER TYPE SYSTEM
A LAKE EFFECT BAND WILL SET UP WHICH WILL INITIALLY BE ORIENTED
TOWARD THE WESTERN ADIRONDACKS AND THEN SLIDE SOUTHEASTWARD INTO
THE MOHAWK VALLEY. AS THIS BAND WILL BE SHORT LIVED WITH A RIDGE
OF HIGH PRESSURE BUILDING QUICKLY INTO THE REGION BY
LATE MORNING...EXPECT THE GREATEST ACCUMULATIONS WILL BE ACROSS
SOUTHERN PORTIONS WESTERN ADIRONDACKS AND THE WESTERN MOHAWK
VALLEY. THIS ADDITIONAL SNOW IN THE WESTERN MOHAWK VALLEY SHOULD
BE ENOUGH TO RESULT IN THE AREA AVERAGING OVER 4 INCHES OF SNOW
WHEN COUPLED WITH THE SNOW FROM THE CLIPPER TYPE SYSTEM. BY MONDAY
AFTERNOON THE RIDGE OF HIGH PRESSURE IS ALREADY CRESTING ACROSS
THE FA AND THEN SLIDING EAST OF THE FA BY EVENING. EXPECT HIGHS ON
MONDAY TO RANGE FROM THE LOW TO MID 20S NORTHWEST TO MID TO UPPER
30S SOUTHEAST.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
MONDAY NIGHT INTO TUESDAY MORNING THE FA IS EXPECTED TO BE
IMPACTED BY A WARM FRONT LIFTING NE FROM THE OHIO VALLEY. LIGHT
SNOW IS EXPECTED TO OVERSPREAD MUCH OF THE FA FROM SOUTHWEST TO
NORTHEAST MONDAY EVENING WITH THE HIGHEST QPF FROM THE MOHAWK
VALLEY NORTH IN NEW YORK AND ACROSS SOUTHERN VERMONT. THIS EVENT
GENERALLY LOOKS LIKE 2 TO 4 INCHES TOTAL ACROSS NORTHWEST PORTIONS
OF THE FA WITH MOST OTHER AREAS HAVING AROUND AN INCH OF
SNOW...ALTHOUGH THE MOUNTAINS EITHER SIDE OF THE GREATER CAPITAL
DISTRICT MAY PICK UP A COUPLE OF INCHES. EXPECT LOWS MONDAY NIGHT
TO BE IN THE MID TEENS TO MID 20S.
TUESDAY AFTERNOON INTO TUESDAY NIGHT EXPECT THE WARM FRONT TO BE
NORTH OF THE BULK OF THE FA BY TUESDAY EVENING WITH THE FA LEFT IN
THE WARM SECTOR. THERE WILL STILL BE A CHANCE OF PCPN TUESDAY
AFTERNOON INTO TUESDAY NIGHT MAINLY ACROSS THE NORTHERN HALF OF
THE FA UNTIL THE COLD FRONT ARRIVES ON WEDNESDAY. EXPECT HIGHS ON
TUESDAY TO RANGE FROM THE MID 30S NORTHWEST TO UPPER 40S TO AROUND
50 SOUTHEAST WITH LOWS TUESDAY NIGHT RANGING FROM THE UPPER 20S TO
LOWER 30S NORTH TO MID 30S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST STARTS OUT VERY MILD MID WEEK...AND THEN
BECOMES VERY UNSETTLED WITH CONTINUED MEDIUM RANGE DETERMINISTIC AND
ENSEMBLE MODEL UNCERTAINTY...WITH A LOW CONFIDENCE FORECAST FROM
THURSDAY INTO WEEKEND. WE WENT CLOSE TO THE HPC GUIDANCE...HOWEVER
THE LATEST 12Z ECMWF WOULD INDICATE THAT TWO SEPARATE SYSTEMS IN THE
W/SW FLOW COULD IMPACT THE NORTHEAST THU NIGHT THROUGH FRIDAY...AND
ANOTHER SYSTEM LATER ON THE WEEKEND WITH SOME SNOW. THE CANADIAN
GGEM IS ALSO HINTING AT ANOTHER SYSTEM DEVELOPING SATURDAY NEXT
WEEKEND OVER THE CNTRL MS RIVER VALLEY THAT COULD IMPACT THE
NORTHEAST FOR SUNDAY TOO. MEANWHILE...THE GFS IS COLD AND DRY LATE
IN THE WEEK WITH A SHORT-WAVE TROUGH IN THE NW FLOW THAT COULD
PRODUCE SOME SOME SNOW SHOWERS LATER NEXT WEEKEND.
WED-WED NIGHT...HIGH PRESSURE RETREATS OFF THE MID ATLANTIC
COAST...AS A WAVE OF LOW PRESSURE MOVES ACROSS SRN QUEBEC. MOST OF
THE FCST AREA GETS INTO A WARM SECTOR WITH H850 TEMPS JUMPING UP TO
+1 TO +5C. MAX TEMPS COULD BE 10 TO 20 DEGREES ABOVE NORMAL WITH
HIGHS IN THE M40S TO L50S IN THE VALLEYS...AND LOWER TO M40S OVER
THE HILLS AND MTNS. THE COLD FRONT QUICKLY APPROACHES LATE IN THE
DAY INTO THE EVENING WITH A GOOD CHANCE OF SHOWERS...TRANSITIONING
TO SNOW SHOWERS WITH THE COLD AIR ADVECTION. WE KEPT THE TREND OF
LIKELY POPS NORTH OF THE CAPITAL REGION CLOSER TO THE BETTER
CONVERGENCE AND LIFT WITH THE WAVE AND FRONT. LOWS WILL RANGE FROM
THE LOWER TO M20S OVER THE MTNS...AND U20S TO L30S IN THE VALLEYS.
THU-THU NIGHT...THE GFS HAS HIGH PRESSURE BUILDING IN FROM SRN
QUEBEC WITH A BROAD LONGWAVE TROUGH OVER THE NRN TIER. THE ECMWF
HAS A SHORT-WAVE IN THE SRN STREAM PHASING INTO THE NRN STREAM NEAR
THE CNTRL MS RIVER VALLEY...AND MOVES IT INTO THE OHIO VALLEY BY
THURSDAY MORNING. THIS SYSTEM MOVES ALONG THE BAROCLINIC ZONE FROM
THE FRONTAL PASSAGE ON WED NIGHT. THE SFC WAVE MOVES NORTHEAST INTO
PA AND UPSTATE NY BY LATE IN THE DAY ON THU VIA THE ECMWF. THE HPC
GUIDANCE...AND GFS HAVE A SECONDARY COLD FRONT SLIP SOUTH OF THE
REGION DURING THE DAY...AND THE WAVE IS MUCH FLATTER PASSING SOUTH
OF THE REGION. WE KEPT MUCH OF THE DAY DRY ON THU WITH HIGH
PRESSURE IN CONTROL. WE DID ADD A SLIGHT CHC OF SNOW THU NIGHT
OVER MOST OF THE REGION IN THE GRIDDED FCST JUST IN CASE THE ECMWF
IS CORRECT HERE. LATER RUNS OF THE GFS COULD TREND FURTHER NORTHWARD
WITH THE ACTIVE W/SW FLOW ALOFT.
FRI-FRI NIGHT...THIS IS WHERE THE MEDIUM RANGE GUIDANCE CONTINUES TO
DIVERGE. THE HPC GUIDANCE AND GFS HAVE A COLD FRONT MOVING SOUTH
WITH HIGH PRESSURE RIDGING BACK IN WITH A NRN STREAM DISTURBANCE
DIGGING S/SE FROM THE UPPER MIDWEST. THE SUBTROPICAL JET/SRN STREAM
DISTURBANCE IS EJECTING OUT OF TX. WE KEPT SOME SLIGHT OR LOW CHC
POPS IN FOR SNOW SHOWERS OR LIGHT SNOW DURING THIS TIME FRAME WITH
THE FIRST WAVE MOVING INTO GULF OF MAINE AND THE CANADIAN
MARITIMES. THE ECMWF/CANADIAN GGEM/SOME GLOBAL ENSEMBLES MEMBERS
HAVE A AN IMPRESSIVE SYSTEM FORMING OVER THE SRN PLAINS/LOWER MS
RIVER VALLEY FRI NIGHT WITH A POSITIVELY TILTED LONGWAVE TROUGH
BEING CARVED OUT OVER THE CNTRL PLAINS.
SAT-SUN...VERY LOW CONFIDENCE FORECAST CONTINUES. CAN GGEM AND
ECMWF CONTINUES TO HAVE COASTAL WAVE MOVING NORTHEAST INTO MID
ATLANTIC REGION...AND SOUTH OF LONG ISLAND BY SUNDAY. THE 18Z HPC
GUIDANCE IS TRENDING FURTHER NORTH LATE SAT INTO SUNDAY WITH THE
WAVE. WE KEPT SLIGHT TO LOW CHC POPS IN FOR THE WEEKEND WITH SNOW
AS THE MAIN PTYPE /AS SUFFICIENTLY COLD ENOUGH AIR IS IMPLIED/. THE
TIMING AND EVOLUTION OF THE LATE WEEK INTO THE WEEKEND SYSTEMS IS
VERY UNCERTAIN. IT COULD BE VERY ACTIVE. TEMPS LOOK TO AVERAGE
NEAR NORMAL FOR FEBRUARY DURING THIS STRETCH.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AN UPPER LEVEL DISTURBANCE AND FRONTAL BOUNDARY WILL CROSS THE REGION
OVERNIGHT ACCOMPANIED BY SNOW SHOWERS AND SOME SNOW SQUALLS. MVFR
CONDITIONS ARE EXPECTED AS THE SHOWERS MOVE THROUGH AT KGFL AND
KALB. IF A SNOW SQUALL OCCURS THEN A BRIEF PERIOD OF IFR WILL OCCUR
AS IT MOVES THROUGH...HOWEVER DO NOT HAVE ENOUGH CONFIDENCE TO PUT
THAT IN THE TAFS. AT KPOU...HAVE ADDRESSED SNOW SHOWERS WILL
VICINITY SHOWERS AS IT APPEARS THE ACTIVITY SHOULD PASS TO THE
NORTH.
CLOUD COVER IS EXPECTED TO DECREASE FOR A PERIOD LATE TONIGHT INTO
THE DAY MONDAY...THEN CLOUDS AHEAD OF AN APPROACHING WARM FRONT WILL
STREAM IN BY EVENING TIME. PRECIPITATION...SNOW...ASSOCIATED WITH
WARM AIR ADVECTION SHOULD DEVELOP/ARRIVE AROUND 06Z/TUESDAY.
SURFACE WINDS ARE LIGHT AND SOUTHERLY TO CALM AT THIS TIME AND WILL
SWING AROUND TO THE WEST WITH THE PASSAGE OF THE FRONTAL BOUNDARY.
THE WESTERLY WINDS ARE EXPECTED TO BECOME GUSTY MONDAY MORNING AS
THE ATMOSPHERE MIXES...THEN BY LATE IN THE DAY DECREASE TO LESS THAN
10 KNOTS.
OUTLOOK...
MON NIGHT...VFR/MVFR WITH BECOMING -SN LIKELY LATE.
TUE...VFR/MVFR AT KGFL AND KALB WITH CHC -SHRA/-SHSN. KPOU VFR.
TUE NIGHT-WED...VFR/MVFR. CHC -SHRA/-SHSN
THU...VFR. SLIGHT CHC -SHRA/-SHSN AT NIGHT.
FRI...VFR. CHC -SNSH.
&&
.HYDROLOGY...
RIVER FLOWS CONTINUE TO RECEDE...ALTHOUGH SOME GAGE SITES REMAIN
IMPACTED BY ICE INCLUDING MCKN6. NO MAJOR PROBLEMS ARE EXPECTED ON
THE RIVERS THROUGH THE MID WEEK PERIOD...OTHER THAN THOSE AREAS
SUCH AS MCKN6 WHERE ICE JAMS ARE STILL A POSSIBILITY. THE
PRECIPITATION THROUGH THE MID WEEK PERIOD IS EXPECTED TO BE MAINLY
IN THE FORM OF SNOW WITH QPF AMOUNTS RANGING FROM A FEW HUNDREDTHS
OF AN INCH TO A QUARTER TO A THIRD OF AN INCH ACROSS NORTHWEST
PORTIONS OF THE HSA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NYZ032-033-038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/11
NEAR TERM...FRUGIS/GJM/JPV
SHORT TERM...11
LONG TERM...WASULA
AVIATION...IAA
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
100 AM EST MON JAN 30 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING SNOW SHOWERS AND
SQUALLS TONIGHT...MAINLY FOR WESTERN AND NORTHERN PARTS OF THE
REGION. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON
MONDAY BEFORE BEING FOLLOWED BY A WARM FRONT...WHICH WILL BRING
ANOTHER ROUND OF SNOW TO THE AREA FOR MONDAY NIGHT INTO TUESDAY
MORNING.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1245 AM...POTENT BUT COMPACT UPPER LEVEL DISTURBANCE
CLEARLY EVIDENT OF WATER VAPOR IMAGERY WITH A DISTINCT SWIRL SEEN
WITH COMMA-HEAD MOVING INTO EAST CENTRAL NY. SNOW SQUALL ACTIVITY
NOT AS WIDESPREAD AS EARLY ACROSS WESTERN/CENTRAL NY. BROKEN LINES
OF SNOW SHOWERS WITH A FEW BRIEF INTENSE SQUALLS WILL CONTINUE TO
BE POSSIBLE THROUGH THE REST OF THE NIGHT...MAINLY ACROSS THE
HIGHER TERRAIN WEST OF THE CAPITAL REGION. WILL NOT MAKE ANY
CHANGES TO SNOWFALL FORECAST OR HEADLINES AT THIS TIME AS REPORTS
ARE SCARCE THIS TIME OF DAY. ALSO UPDATED HOURLY GRIDS TO REFLECT
CURRENT OBS AND TRENDS.
PREVIOUS NEAR TERM DISCUSSIONS...
AS OF 1000 PM...INTENSE NORTH-SOUTH SNOW SQUALL THAT WAS MOVING
ACROSS WESTERN AND CENTRAL PA/NY HAD WEAKENED AND BROKEN UP
CONSIDERABLY. RADAR STILL SHOWS SOME SNOW SQUALLS PRODUCING HEAVY
SNOW...BUT MOST OF THESE WILL MOVE ACROSS HERKIMER AND HAMILTON
COUNTIES WHERE WINTER WEATHER ADVISORIES ARE ALREADY UP. ELSEWHERE
THE SNOW SHOWERS WILL CONTINUE TO DECREASE IN COVERAGE AS THEY MOVE
EAST. IN GENERAL HAVE RAISED POPS TO LIKELY ACROSS THE EASTERN
CATSKILLS AND NORTHERN BERKSHIRE COUNTY...WITH LIKELY POPS OR HIGHER
ALREADY IN THE GRIDS IN AREAS FURTHER NORTH. FROM THE CAPITAL
DISTRICT TO THE MID HUDSON VALLEY AND SOUTHERN BERKSHIRE COUNTY AND
LITCHFIELD COUNTY...HAVE ALSO RAISED POPS IN THESE AREAS...BUT THE
FORECAST REMAINS IN THE CHANCE CATEGORY. REST OF THE PREVIOUS
FORECAST GENERALLY UNCHANGED.
AS OF 648 PM EST...HAVE UPDATED T/TD TO ACCOUNT FOR LATEST
OBSERVATIONS AND TRENDS. CURRENT FORECAST MIN TEMPS APPEAR ON
TRACK WITH 20S FOR MOST AREAS /SOME TEENS ACROSS THE SRN ADKS/.
LATEST RADAR RETURNS SHOW SOME MODERATE SNOWFALL DUE TO SOME LAKE
MOISTURE UPSLOPING THE HIGH TERRAIN AFFECTING THE WESTERN
ADKS...MAINLY TO THE NORTH OF OLD FORGE AND INLET. THIS LOOKS TO
CONTINUE OVER THE NEXT SEVERAL HOURS...WITH A FEW INCHES POSSIBLE.
THIS ACTIVITY WILL WANE SOMEWHAT AS THE FLOW SHIFTS AHEAD OF AN
APPROACHING SHORTWAVE AND ASSOCIATED SURFACE BOUNDARY.
THE 20Z 3KM HRRR GUIDANCE STILL DEPICTS A FAST MOVING LINE OF SNOW
SHOWERS/SQUALLS ASSOCIATED WITH THE AFOREMENTIONED COLD FRONTAL
BOUNDARY HEADING TOWARDS OUR AREA AROUND MIDNIGHT. MODEL GUIDANCE
SUGGESTS THAT THIS ACTIVITY WON/T BE QUITE AS STRONG AS IT WILL BE
EARLIER IN THE EVENING ACROSS WESTERN NY/WESTERN AND CENTRAL
PA...BUT IT SHOULD STILL BE ENOUGH TO BRING ADDITIONAL ACCUMULATION
AND PROVIDE LOW VISIBILITY WITHIN GUSTY WINDS. THE 18Z NAM STILL
DEPICTS SHOWALTER VALUES NEAR OR JUST BELOW ZERO FOR WESTERN PARTS
OF THE AREA. LTG DETECTION HAS ALREADY NOTED SOME LTG ACROSS
WESTERN PA AND WESTERN NY...SO CANNOT TOTALLY RULE OUT SOME LTG
WITHIN THE HEAVIEST SQUALLS. HOWEVER...DO NOT FEEL CONFIDENT THIS
WILL BE WIDESPREAD ENOUGH TO INCLUDE IN THE GRIDS...BUT IT
CERTAINLY COULD OCCUR IN A FEW ISOLD SPOTS. THE BEST CHANCE OF
SEEING THE SNOW SQUALLS WILL BE ACROSS THE MOHAWK VALLEY/SRN
ADIRONDACKS AND EVENTUALLY THE LAKE GEORGE SARATOGA REGION...WHERE
WE CURRENTLY HAVE THE HIGHEST POPS /LIKELY TO CATEGORICAL/. THE
ACTIVITY LOOKS TO WEAKEN ENOUGH FOR SNOW SHOWERS TO BE RATHER SCT
ONCE ACTIVITY GETS TOWARDS THE CAPITAL REGION BY AROUND 06Z TO
07Z. WHILE A COATING OF SNOWFALL IS POSSIBLE...THE LINE LOOKS TO
BREAK ENOUGH FOR IT TO BE HIT OR MISS ACROSS FOR THE CAPITAL REGION.
FURTHER SOUTH...DOWNLOPING OFF THE CATSKILLS SHOULD KEEP ANY
ACTIVITY FAIRLY ISOLD FOR THE MID HUDSON VALLEY AND NW
CT...ALTHOUGH UPSLOPE FLOW COULD ALLOW FOR A LITTLE BETTER
COVERAGE ACROSS THE TACONICS/BERKSHIRES/SOUTHERN GREENS...WHERE A
LIGHT ACCUMULATION IS POSSIBLE.
LATE TONIGHT AND MONDAY...IN THE WAKE OF THE CLIPPER TYPE SYSTEM
A LAKE EFFECT BAND WILL SET UP WHICH WILL INITIALLY BE ORIENTED
TOWARD THE WESTERN ADIRONDACKS AND THEN SLIDE SOUTHEASTWARD INTO
THE MOHAWK VALLEY. AS THIS BAND WILL BE SHORT LIVED WITH A RIDGE
OF HIGH PRESSURE BUILDING QUICKLY INTO THE REGION BY
LATE MORNING...EXPECT THE GREATEST ACCUMULATIONS WILL BE ACROSS
SOUTHERN PORTIONS WESTERN ADIRONDACKS AND THE WESTERN MOHAWK
VALLEY. THIS ADDITIONAL SNOW IN THE WESTERN MOHAWK VALLEY SHOULD
BE ENOUGH TO RESULT IN THE AREA AVERAGING OVER 4 INCHES OF SNOW
WHEN COUPLED WITH THE SNOW FROM THE CLIPPER TYPE SYSTEM. BY MONDAY
AFTERNOON THE RIDGE OF HIGH PRESSURE IS ALREADY CRESTING ACROSS
THE FA AND THEN SLIDING EAST OF THE FA BY EVENING. EXPECT HIGHS ON
MONDAY TO RANGE FROM THE LOW TO MID 20S NORTHWEST TO MID TO UPPER
30S SOUTHEAST.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
MONDAY NIGHT INTO TUESDAY MORNING THE FA IS EXPECTED TO BE
IMPACTED BY A WARM FRONT LIFTING NE FROM THE OHIO VALLEY. LIGHT
SNOW IS EXPECTED TO OVERSPREAD MUCH OF THE FA FROM SOUTHWEST TO
NORTHEAST MONDAY EVENING WITH THE HIGHEST QPF FROM THE MOHAWK
VALLEY NORTH IN NEW YORK AND ACROSS SOUTHERN VERMONT. THIS EVENT
GENERALLY LOOKS LIKE 2 TO 4 INCHES TOTAL ACROSS NORTHWEST PORTIONS
OF THE FA WITH MOST OTHER AREAS HAVING AROUND AN INCH OF
SNOW...ALTHOUGH THE MOUNTAINS EITHER SIDE OF THE GREATER CAPITAL
DISTRICT MAY PICK UP A COUPLE OF INCHES. EXPECT LOWS MONDAY NIGHT
TO BE IN THE MID TEENS TO MID 20S.
TUESDAY AFTERNOON INTO TUESDAY NIGHT EXPECT THE WARM FRONT TO BE
NORTH OF THE BULK OF THE FA BY TUESDAY EVENING WITH THE FA LEFT IN
THE WARM SECTOR. THERE WILL STILL BE A CHANCE OF PCPN TUESDAY
AFTERNOON INTO TUESDAY NIGHT MAINLY ACROSS THE NORTHERN HALF OF
THE FA UNTIL THE COLD FRONT ARRIVES ON WEDNESDAY. EXPECT HIGHS ON
TUESDAY TO RANGE FROM THE MID 30S NORTHWEST TO UPPER 40S TO AROUND
50 SOUTHEAST WITH LOWS TUESDAY NIGHT RANGING FROM THE UPPER 20S TO
LOWER 30S NORTH TO MID 30S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST STARTS OUT VERY MILD MID WEEK...AND THEN
BECOMES VERY UNSETTLED WITH CONTINUED MEDIUM RANGE DETERMINISTIC AND
ENSEMBLE MODEL UNCERTAINTY...WITH A LOW CONFIDENCE FORECAST FROM
THURSDAY INTO WEEKEND. WE WENT CLOSE TO THE HPC GUIDANCE...HOWEVER
THE LATEST 12Z ECMWF WOULD INDICATE THAT TWO SEPARATE SYSTEMS IN THE
W/SW FLOW COULD IMPACT THE NORTHEAST THU NIGHT THROUGH FRIDAY...AND
ANOTHER SYSTEM LATER ON THE WEEKEND WITH SOME SNOW. THE CANADIAN
GGEM IS ALSO HINTING AT ANOTHER SYSTEM DEVELOPING SATURDAY NEXT
WEEKEND OVER THE CNTRL MS RIVER VALLEY THAT COULD IMPACT THE
NORTHEAST FOR SUNDAY TOO. MEANWHILE...THE GFS IS COLD AND DRY LATE
IN THE WEEK WITH A SHORT-WAVE TROUGH IN THE NW FLOW THAT COULD
PRODUCE SOME SOME SNOW SHOWERS LATER NEXT WEEKEND.
WED-WED NIGHT...HIGH PRESSURE RETREATS OFF THE MID ATLANTIC
COAST...AS A WAVE OF LOW PRESSURE MOVES ACROSS SRN QUEBEC. MOST OF
THE FCST AREA GETS INTO A WARM SECTOR WITH H850 TEMPS JUMPING UP TO
+1 TO +5C. MAX TEMPS COULD BE 10 TO 20 DEGREES ABOVE NORMAL WITH
HIGHS IN THE M40S TO L50S IN THE VALLEYS...AND LOWER TO M40S OVER
THE HILLS AND MTNS. THE COLD FRONT QUICKLY APPROACHES LATE IN THE
DAY INTO THE EVENING WITH A GOOD CHANCE OF SHOWERS...TRANSITIONING
TO SNOW SHOWERS WITH THE COLD AIR ADVECTION. WE KEPT THE TREND OF
LIKELY POPS NORTH OF THE CAPITAL REGION CLOSER TO THE BETTER
CONVERGENCE AND LIFT WITH THE WAVE AND FRONT. LOWS WILL RANGE FROM
THE LOWER TO M20S OVER THE MTNS...AND U20S TO L30S IN THE VALLEYS.
THU-THU NIGHT...THE GFS HAS HIGH PRESSURE BUILDING IN FROM SRN
QUEBEC WITH A BROAD LONGWAVE TROUGH OVER THE NRN TIER. THE ECMWF
HAS A SHORT-WAVE IN THE SRN STREAM PHASING INTO THE NRN STREAM NEAR
THE CNTRL MS RIVER VALLEY...AND MOVES IT INTO THE OHIO VALLEY BY
THURSDAY MORNING. THIS SYSTEM MOVES ALONG THE BAROCLINIC ZONE FROM
THE FRONTAL PASSAGE ON WED NIGHT. THE SFC WAVE MOVES NORTHEAST INTO
PA AND UPSTATE NY BY LATE IN THE DAY ON THU VIA THE ECMWF. THE HPC
GUIDANCE...AND GFS HAVE A SECONDARY COLD FRONT SLIP SOUTH OF THE
REGION DURING THE DAY...AND THE WAVE IS MUCH FLATTER PASSING SOUTH
OF THE REGION. WE KEPT MUCH OF THE DAY DRY ON THU WITH HIGH
PRESSURE IN CONTROL. WE DID ADD A SLIGHT CHC OF SNOW THU NIGHT
OVER MOST OF THE REGION IN THE GRIDDED FCST JUST IN CASE THE ECMWF
IS CORRECT HERE. LATER RUNS OF THE GFS COULD TREND FURTHER NORTHWARD
WITH THE ACTIVE W/SW FLOW ALOFT.
FRI-FRI NIGHT...THIS IS WHERE THE MEDIUM RANGE GUIDANCE CONTINUES TO
DIVERGE. THE HPC GUIDANCE AND GFS HAVE A COLD FRONT MOVING SOUTH
WITH HIGH PRESSURE RIDGING BACK IN WITH A NRN STREAM DISTURBANCE
DIGGING S/SE FROM THE UPPER MIDWEST. THE SUBTROPICAL JET/SRN STREAM
DISTURBANCE IS EJECTING OUT OF TX. WE KEPT SOME SLIGHT OR LOW CHC
POPS IN FOR SNOW SHOWERS OR LIGHT SNOW DURING THIS TIME FRAME WITH
THE FIRST WAVE MOVING INTO GULF OF MAINE AND THE CANADIAN
MARITIMES. THE ECMWF/CANADIAN GGEM/SOME GLOBAL ENSEMBLES MEMBERS
HAVE A AN IMPRESSIVE SYSTEM FORMING OVER THE SRN PLAINS/LOWER MS
RIVER VALLEY FRI NIGHT WITH A POSITIVELY TILTED LONGWAVE TROUGH
BEING CARVED OUT OVER THE CNTRL PLAINS.
SAT-SUN...VERY LOW CONFIDENCE FORECAST CONTINUES. CAN GGEM AND
ECMWF CONTINUES TO HAVE COASTAL WAVE MOVING NORTHEAST INTO MID
ATLANTIC REGION...AND SOUTH OF LONG ISLAND BY SUNDAY. THE 18Z HPC
GUIDANCE IS TRENDING FURTHER NORTH LATE SAT INTO SUNDAY WITH THE
WAVE. WE KEPT SLIGHT TO LOW CHC POPS IN FOR THE WEEKEND WITH SNOW
AS THE MAIN PTYPE /AS SUFFICIENTLY COLD ENOUGH AIR IS IMPLIED/. THE
TIMING AND EVOLUTION OF THE LATE WEEK INTO THE WEEKEND SYSTEMS IS
VERY UNCERTAIN. IT COULD BE VERY ACTIVE. TEMPS LOOK TO AVERAGE
NEAR NORMAL FOR FEBRUARY DURING THIS STRETCH.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE KGFL/KALB/KPOU TAF SITES
THROUGH THE TAF PERIOD ENDING AT 00Z TUESDAY. HOWEVER...AS ANOTHER
FRONTAL BOUNDARY CROSSES THE REGION DURING THE NITE...THERE IS THE
POTENTIAL FOR MVFR/IFR CONDITIONS IN SNOW SHOWERS BEFORE/DURING AND
AFTER FORNTAL PASSAGE. THE CHANCES ARE BEST AT KGFL WHERE A PERIOD
OF MVFR CONDITIONS HAVE BEEN FORECAST BETWEEN 05Z AND 10Z...WITH A
TEMPO GROUP FOR IFR VSBYS IN SNOW SHOWERS BETWEEN 05Z AND 08Z. MUCH
LESS THREAT FOR MVFR/IFR CONDITIONS AT KALB...SO ONLY VCSH HAS BEEN
INCLUDED IN THE FORECAST. AT KPOU NO PCPN IS EXPECTED DURING THE TAF
PERIOD. AFTER ABOUT 10Z...VFR CONDITIONS WILL PREVAIL AT ALL THREE
TAF SITES AS GUSTY WESTERLY WINDS BRING COLDER AIR TO THE REGION AND
GNERALLY SCT/BKN CU/SC.
SURFACE WINDS WILL BE 10 KTS OR LESS FROM THE SOUTH OR SOUTHWEST
THIS EVENING AHEAD OF THE FRONTAL BOUNDARY. WINDS WILL SHOFT BETWEEN
05Z AND 07Z AT THE TAF SITES AND BECOME WESTERLY AT 10 TO 15 KTS
WITH GUSTS OF 15 TO 25 KTS BEHIND THE FRONT AND THROUGH MOST OF
MONDAY. BY LATE IN THE DAY ON MONDAY THE WINDS WILL DECREASE TO LESS
THAN 10 KTS.
CLOUDS WILL ALSO BEGIN TO INCREASE AGAIN LATE IN THE DAY AHEAD OF A
WARM FRONT.
OUTLOOK...
MON NIGHT...VFR/MVFR WITH -SN LIKELY.
TUE...VFR/MVFR AT KGFL WITH -SN LIKELY ESP IN THE MORNING. KALB
SOUTH TO KPOU VFR.
TUE NIGHT-WED...VFR/MVFR. CHC -SHRA/-SHSN.
THU...VFR...SLIGHT CHC -SHRA AT KPOU.
FRI...VFR...SLIGHT CHC -SHRA/-SNSHS.
&&
.HYDROLOGY...
RIVER FLOWS CONTINUE TO RECEDE...ALTHOUGH SOME GAGE SITES REMAIN
IMPACTED BY ICE INCLUDING MCKN6. NO MAJOR PROBLEMS ARE EXPECTED ON
THE RIVERS THROUGH THE MID WEEK PERIOD...OTHER THAN THOSE AREAS
SUCH AS MCKN6 WHERE ICE JAMS ARE STILL A POSSIBILITY. THE
PRECIPITATION THROUGH THE MID WEEK PERIOD IS EXPECTED TO BE MAINLY
IN THE FORM OF SNOW WITH QPF AMOUNTS RANGING FROM A FEW HUNDREDTHS
OF AN INCH TO A QUARTER TO A THIRD OF AN INCH ACROSS NORTHWEST
PORTIONS OF THE HSA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NYZ032-033-038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/11
NEAR TERM...FRUGIS/GJM/JPV
SHORT TERM...11
LONG TERM...WASUIAGJM
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
1248 AM EST MON JAN 30 2012
.SYNOPSIS...
A FAST MOVING COLD FRONT WILL BRING SNOW SHOWERS AND
SQUALLS TONIGHT...MAINLY FOR WESTERN AND NORTHERN PARTS OF THE
REGION. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON
MONDAY BEFORE BEING FOLLOWED BY A WARM FRONT...WHICH WILL BRING
ANOTHER ROUND OF SNOW TO THE AREA FOR MONDAY NIGHT INTO TUESDAY
MORNING.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1245 AM...POTENT BUT COMPACT UPPER LEVEL DISTURBANCE
CLEARLY EVIDENT OF WATER VAPOR IMAGERY WITH A DISTINCT SWIRL SEEN
WITH COMMA-HEAD MOVING INTO EAST CENTRAL NY. SNOW SQUALL ACTIVITY
NOT AS WIDESPREAD AS EARLY ACROSS WESTERN/CENTRAL NY. BROKEN LINES
OF SNOW SHOWERS WITH A FEW BRIEF INTENSE SQUALLS WILL CONTINUE TO
BE POSSIBLE THROUGH THE REST OF THE NIGHT...MAINLY ACROSS THE
HIGHER TERRAIN WEST OF THE CAPITAL REGION. WILL NOT MAKE ANY
CHANGES TO SNOWFALL FORECAST OR HEADLINES AT THIS TIME AS REPORTS
ARE SCARCE THIS TIME OF DAY. ALSO UPDATED HOURLY GRIDS TO REFLECT
CURRENT OBS AND TRENDS.
PREVIOUS NEAR TERM DISCUSSIONS...
AS OF 1000 PM...INTENSE NORTH-SOUTH SNOW SQUALL THAT WAS MOVING
ACROSS WESTERN AND CENTRAL PA/NY HAD WEAKENED AND BROKEN UP
CONSIDERABLY. RADAR STILL SHOWS SOME SNOW SQUALLS PRODUCING HEAVY
SNOW...BUT MOST OF THESE WILL MOVE ACROSS HERKIMER AND HAMILTON
COUNTIES WHERE WINTER WEATHER ADVISORIES ARE ALREADY UP. ELSEWHERE
THE SNOW SHOWERS WILL CONTINUE TO DECREASE IN COVERAGE AS THEY MOVE
EAST. IN GENERAL HAVE RAISED POPS TO LIKELY ACROSS THE EASTERN
CATSKILLS AND NORTHERN BERKSHIRE COUNTY...WITH LIKELY POPS OR HIGHER
ALREADY IN THE GRIDS IN AREAS FURTHER NORTH. FROM THE CAPITAL
DISTRICT TO THE MID HUDSON VALLEY AND SOUTHERN BERKSHIRE COUNTY AND
LITCHFIELD COUNTY...HAVE ALSO RAISED POPS IN THESE AREAS...BUT THE
FORECAST REMAINS IN THE CHANCE CATEGORY. REST OF THE PREVIOUS
FORECAST GENERALLY UNCHANGED.
AS OF 648 PM EST...HAVE UPDATED T/TD TO ACCOUNT FOR LATEST
OBSERVATIONS AND TRENDS. CURRENT FORECAST MIN TEMPS APPEAR ON
TRACK WITH 20S FOR MOST AREAS /SOME TEENS ACROSS THE SRN ADKS/.
LATEST RADAR RETURNS SHOW SOME MODERATE SNOWFALL DUE TO SOME LAKE
MOISTURE UPSLOPING THE HIGH TERRAIN AFFECTING THE WESTERN
ADKS...MAINLY TO THE NORTH OF OLD FORGE AND INLET. THIS LOOKS TO
CONTINUE OVER THE NEXT SEVERAL HOURS...WITH A FEW INCHES POSSIBLE.
THIS ACTIVITY WILL WANE SOMEWHAT AS THE FLOW SHIFTS AHEAD OF AN
APPROACHING SHORTWAVE AND ASSOCIATED SURFACE BOUNDARY.
THE 20Z 3KM HRRR GUIDANCE STILL DEPICTS A FAST MOVING LINE OF SNOW
SHOWERS/SQUALLS ASSOCIATED WITH THE AFOREMENTIONED COLD FRONTAL
BOUNDARY HEADING TOWARDS OUR AREA AROUND MIDNIGHT. MODEL GUIDANCE
SUGGESTS THAT THIS ACTIVITY WON/T BE QUITE AS STRONG AS IT WILL BE
EARLIER IN THE EVENING ACROSS WESTERN NY/WESTERN AND CENTRAL
PA...BUT IT SHOULD STILL BE ENOUGH TO BRING ADDITIONAL ACCUMULATION
AND PROVIDE LOW VISIBILITY WITHIN GUSTY WINDS. THE 18Z NAM STILL
DEPICTS SHOWALTER VALUES NEAR OR JUST BELOW ZERO FOR WESTERN PARTS
OF THE AREA. LTG DETECTION HAS ALREADY NOTED SOME LTG ACROSS
WESTERN PA AND WESTERN NY...SO CANNOT TOTALLY RULE OUT SOME LTG
WITHIN THE HEAVIEST SQUALLS. HOWEVER...DO NOT FEEL CONFIDENT THIS
WILL BE WIDESPREAD ENOUGH TO INCLUDE IN THE GRIDS...BUT IT
CERTAINLY COULD OCCUR IN A FEW ISOLD SPOTS. THE BEST CHANCE OF
SEEING THE SNOW SQUALLS WILL BE ACROSS THE MOHAWK VALLEY/SRN
ADIRONDACKS AND EVENTUALLY THE LAKE GEORGE SARATOGA REGION...WHERE
WE CURRENTLY HAVE THE HIGHEST POPS /LIKELY TO CATEGORICAL/. THE
ACTIVITY LOOKS TO WEAKEN ENOUGH FOR SNOW SHOWERS TO BE RATHER SCT
ONCE ACTIVITY GETS TOWARDS THE CAPITAL REGION BY AROUND 06Z TO
07Z. WHILE A COATING OF SNOWFALL IS POSSIBLE...THE LINE LOOKS TO
BREAK ENOUGH FOR IT TO BE HIT OR MISS ACROSS FOR THE CAPITAL REGION.
FURTHER SOUTH...DOWNLOPING OFF THE CATSKILLS SHOULD KEEP ANY
ACTIVITY FAIRLY ISOLD FOR THE MID HUDSON VALLEY AND NW
CT...ALTHOUGH UPSLOPE FLOW COULD ALLOW FOR A LITTLE BETTER
COVERAGE ACROSS THE TACONICS/BERKSHIRES/SOUTHERN GREENS...WHERE A
LIGHT ACCUMULATION IS POSSIBLE.
LATE TONIGHT AND MONDAY...IN THE WAKE OF THE CLIPPER TYPE SYSTEM
A LAKE EFFECT BAND WILL SET UP WHICH WILL INITIALLY BE ORIENTED
TOWARD THE WESTERN ADIRONDACKS AND THEN SLIDE SOUTHEASTWARD INTO
THE MOHAWK VALLEY. AS THIS BAND WILL BE SHORT LIVED WITH A RIDGE
OF HIGH PRESSURE BUILDING QUICKLY INTO THE REGION BY
LATE MORNING...EXPECT THE GREATEST ACCUMULATIONS WILL BE ACROSS
SOUTHERN PORTIONS WESTERN ADIRONDACKS AND THE WESTERN MOHAWK
VALLEY. THIS ADDITIONAL SNOW IN THE WESTERN MOHAWK VALLEY SHOULD
BE ENOUGH TO RESULT IN THE AREA AVERAGING OVER 4 INCHES OF SNOW
WHEN COUPLED WITH THE SNOW FROM THE CLIPPER TYPE SYSTEM. BY MONDAY
AFTERNOON THE RIDGE OF HIGH PRESSURE IS ALREADY CRESTING ACROSS
THE FA AND THEN SLIDING EAST OF THE FA BY EVENING. EXPECT HIGHS ON
MONDAY TO RANGE FROM THE LOW TO MID 20S NORTHWEST TO MID TO UPPER
30S SOUTHEAST.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
MONDAY NIGHT INTO TUESDAY MORNING THE FA IS EXPECTED TO BE
IMPACTED BY A WARM FRONT LIFTING NE FROM THE OHIO VALLEY. LIGHT
SNOW IS EXPECTED TO OVERSPREAD MUCH OF THE FA FROM SOUTHWEST TO
NORTHEAST MONDAY EVENING WITH THE HIGHEST QPF FROM THE MOHAWK
VALLEY NORTH IN NEW YORK AND ACROSS SOUTHERN VERMONT. THIS EVENT
GENERALLY LOOKS LIKE 2 TO 4 INCHES TOTAL ACROSS NORTHWEST PORTIONS
OF THE FA WITH MOST OTHER AREAS HAVING AROUND AN INCH OF
SNOW...ALTHOUGH THE MOUNTAINS EITHER SIDE OF THE GREATER CAPITAL
DISTRICT MAY PICK UP A COUPLE OF INCHES. EXPECT LOWS MONDAY NIGHT
TO BE IN THE MID TEENS TO MID 20S.
TUESDAY AFTERNOON INTO TUESDAY NIGHT EXPECT THE WARM FRONT TO BE
NORTH OF THE BULK OF THE FA BY TUESDAY EVENING WITH THE FA LEFT IN
THE WARM SECTOR. THERE WILL STILL BE A CHANCE OF PCPN TUESDAY
AFTERNOON INTO TUESDAY NIGHT MAINLY ACROSS THE NORTHERN HALF OF
THE FA UNTIL THE COLD FRONT ARRIVES ON WEDNESDAY. EXPECT HIGHS ON
TUESDAY TO RANGE FROM THE MID 30S NORTHWEST TO UPPER 40S TO AROUND
50 SOUTHEAST WITH LOWS TUESDAY NIGHT RANGING FROM THE UPPER 20S TO
LOWER 30S NORTH TO MID 30S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST STARTS OUT VERY MILD MID WEEK...AND THEN
BECOMES VERY UNSETTLED WITH CONTINUED MEDIUM RANGE DETERMINISTIC AND
ENSEMBLE MODEL UNCERTAINTY...WITH A LOW CONFIDENCE FORECAST FROM
THURSDAY INTO WEEKEND. WE WENT CLOSE TO THE HPC GUIDANCE...HOWEVER
THE LATEST 12Z ECMWF WOULD INDICATE THAT TWO SEPARATE SYSTEMS IN THE
W/SW FLOW COULD IMPACT THE NORTHEAST THU NIGHT THROUGH FRIDAY...AND
ANOTHER SYSTEM LATER ON THE WEEKEND WITH SOME SNOW. THE CANADIAN
GGEM IS ALSO HINTING AT ANOTHER SYSTEM DEVELOPING SATURDAY NEXT
WEEKEND OVER THE CNTRL MS RIVER VALLEY THAT COULD IMPACT THE
NORTHEAST FOR SUNDAY TOO. MEANWHILE...THE GFS IS COLD AND DRY LATE
IN THE WEEK WITH A SHORT-WAVE TROUGH IN THE NW FLOW THAT COULD
PRODUCE SOME SOME SNOW SHOWERS LATER NEXT WEEKEND.
WED-WED NIGHT...HIGH PRESSURE RETREATS OFF THE MID ATLANTIC
COAST...AS A WAVE OF LOW PRESSURE MOVES ACROSS SRN QUEBEC. MOST OF
THE FCST AREA GETS INTO A WARM SECTOR WITH H850 TEMPS JUMPING UP TO
+1 TO +5C. MAX TEMPS COULD BE 10 TO 20 DEGREES ABOVE NORMAL WITH
HIGHS IN THE M40S TO L50S IN THE VALLEYS...AND LOWER TO M40S OVER
THE HILLS AND MTNS. THE COLD FRONT QUICKLY APPROACHES LATE IN THE
DAY INTO THE EVENING WITH A GOOD CHANCE OF SHOWERS...TRANSITIONING
TO SNOW SHOWERS WITH THE COLD AIR ADVECTION. WE KEPT THE TREND OF
LIKELY POPS NORTH OF THE CAPITAL REGION CLOSER TO THE BETTER
CONVERGENCE AND LIFT WITH THE WAVE AND FRONT. LOWS WILL RANGE FROM
THE LOWER TO M20S OVER THE MTNS...AND U20S TO L30S IN THE VALLEYS.
THU-THU NIGHT...THE GFS HAS HIGH PRESSURE BUILDING IN FROM SRN
QUEBEC WITH A BROAD LONGWAVE TROUGH OVER THE NRN TIER. THE ECMWF
HAS A SHORT-WAVE IN THE SRN STREAM PHASING INTO THE NRN STREAM NEAR
THE CNTRL MS RIVER VALLEY...AND MOVES IT INTO THE OHIO VALLEY BY
THURSDAY MORNING. THIS SYSTEM MOVES ALONG THE BAROCLINIC ZONE FROM
THE FRONTAL PASSAGE ON WED NIGHT. THE SFC WAVE MOVES NORTHEAST INTO
PA AND UPSTATE NY BY LATE IN THE DAY ON THU VIA THE ECMWF. THE HPC
GUIDANCE...AND GFS HAVE A SECONDARY COLD FRONT SLIP SOUTH OF THE
REGION DURING THE DAY...AND THE WAVE IS MUCH FLATTER PASSING SOUTH
OF THE REGION. WE KEPT MUCH OF THE DAY DRY ON THU WITH HIGH
PRESSURE IN CONTROL. WE DID ADD A SLIGHT CHC OF SNOW THU NIGHT
OVER MOST OF THE REGION IN THE GRIDDED FCST JUST IN CASE THE ECMWF
IS CORRECT HERE. LATER RUNS OF THE GFS COULD TREND FURTHER NORTHWARD
WITH THE ACTIVE W/SW FLOW ALOFT.
FRI-FRI NIGHT...THIS IS WHERE THE MEDIUM RANGE GUIDANCE CONTINUES TO
DIVERGE. THE HPC GUIDANCE AND GFS HAVE A COLD FRONT MOVING SOUTH
WITH HIGH PRESSURE RIDGING BACK IN WITH A NRN STREAM DISTURBANCE
DIGGING S/SE FROM THE UPPER MIDWEST. THE SUBTROPICAL JET/SRN STREAM
DISTURBANCE IS EJECTING OUT OF TX. WE KEPT SOME SLIGHT OR LOW CHC
POPS IN FOR SNOW SHOWERS OR LIGHT SNOW DURING THIS TIME FRAME WITH
THE FIRST WAVE MOVING INTO GULF OF MAINE AND THE CANADIAN
MARITIMES. THE ECMWF/CANADIAN GGEM/SOME GLOBAL ENSEMBLES MEMBERS
HAVE A AN IMPRESSIVE SYSTEM FORMING OVER THE SRN PLAINS/LOWER MS
RIVER VALLEY FRI NIGHT WITH A POSITIVELY TILTED LONGWAVE TROUGH
BEING CARVED OUT OVER THE CNTRL PLAINS.
SAT-SUN...VERY LOW CONFIDENCE FORECAST CONTINUES. CAN GGEM AND
ECMWF CONTINUES TO HAVE COASTAL WAVE MOVING NORTHEAST INTO MID
ATLANTIC REGION...AND SOUTH OF LONG ISLAND BY SUNDAY. THE 18Z HPC
GUIDANCE IS TRENDING FURTHER NORTH LATE SAT INTO SUNDAY WITH THE
WAVE. WE KEPT SLIGHT TO LOW CHC POPS IN FOR THE WEEKEND WITH SNOW
AS THE MAIN PTYPE /AS SUFFICIENTLY COLD ENOUGH AIR IS IMPLIED/. THE
TIMING AND EVOLUTION OF THE LATE WEEK INTO THE WEEKEND SYSTEMS IS
VERY UNCERTAIN. IT COULD BE VERY ACTIVE. TEMPS LOOK TO AVERAGE
NEAR NORMAL FOR FEBRUARY DURING THIS STRETCH.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE KGFL/KALB/KPOU TAF SITES
THROUGH THE TAF PERIOD ENDING AT 00Z TUESDAY. HOWEVER...AS ANOTHER
FRONTAL BOUNDARY CROSSES THE REGION DURING THE NITE...THERE IS THE
POTENTIAL FOR MVFR/IFR CONDITIONS IN SNOW SHOWERS BEFORE/DURING AND
AFTER FORNTAL PASSAGE. THE CHANCES ARE BEST AT KGFL WHERE A PERIOD
OF MVFR CONDITIONS HAVE BEEN FORECAST BETWEEN 05Z AND 10Z...WITH A
TEMPO GROUP FOR IFR VSBYS IN SNOW SHOWERS BETWEEN 05Z AND 08Z. MUCH
LESS THREAT FOR MVFR/IFR CONDITIONS AT KALB...SO ONLY VCSH HAS BEEN
INCLUDED IN THE FORECAST. AT KPOU NO PCPN IS EXPECTED DURING THE TAF
PERIOD. AFTER ABOUT 10Z...VFR CONDITIONS WILL PREVAIL AT ALL THREE
TAF SITES AS GUSTY WESTERLY WINDS BRING COLDER AIR TO THE REGION AND
GNERALLY SCT/BKN CU/SC.
SURFACE WINDS WILL BE 10 KTS OR LESS FROM THE SOUTH OR SOUTHWEST
THIS EVENING AHEAD OF THE FRONTAL BOUNDARY. WINDS WILL SHOFT BETWEEN
05Z AND 07Z AT THE TAF SITES AND BECOME WESTERLY AT 10 TO 15 KTS
WITH GUSTS OF 15 TO 25 KTS BEHIND THE FRONT AND THROUGH MOST OF
MONDAY. BY LATE IN THE DAY ON MONDAY THE WINDS WILL DECREASE TO LESS
THAN 10 KTS.
CLOUDS WILL ALSO BEGIN TO INCREASE AGAIN LATE IN THE DAY AHEAD OF A
WARM FRONT.
OUTLOOK...
MON NIGHT...VFR/MVFR WITH -SN LIKELY.
TUE...VFR/MVFR AT KGFL WITH -SN LIKELY ESP IN THE MORNING. KALB
SOUTH TO KPOU VFR.
TUE NIGHT-WED...VFR/MVFR. CHC -SHRA/-SHSN.
THU...VFR...SLIGHT CHC -SHRA AT KPOU.
FRI...VFR...SLIGHT CHC -SHRA/-SNSHS.
&&
.HYDROLOGY...
RIVER FLOWS CONTINUE TO RECEDE...ALTHOUGH SOME GAGE SITES REMAIN
IMPACTED BY ICE INCLUDING MCKN6. NO MAJOR PROBLEMS ARE EXPECTED ON
THE RIVERS THROUGH THE MID WEEK PERIOD...OTHER THAN THOSE AREAS
SUCH AS MCKN6 WHERE ICE JAMS ARE STILL A POSSIBILITY. THE
PRECIPITATION THROUGH THE MID WEEK PERIOD IS EXPECTED TO BE MAINLY
IN THE FORM OF SNOW WITH QPF AMOUNTS RANGING FROM A FEW HUNDREDTHS
OF AN INCH TO A QUARTER TO A THIRD OF AN INCH ACROSS NORTHWEST
PORTIONS OF THE HSA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NYZ032-033-038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/11
NEAR TERM...FRUGIS/GJM/JPV
SHORT TERM...11
LONG TERM...WASULA
AVIATION...GJM
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1122 AM CST MON JAN 30 2012
.DISCUSSION...
ISSUED 1000 AM CST MON JAN 30 2012
AREA OF MID-LEVEL CLOUDINESS IS NOW GENERALLY NORTH OF A MACOMB TO
EFFINGHAM LINE. LATEST RUC GUIDANCE SHOWING THESE TO RECEDE
ACROSS THE NORTHERN CWA THROUGH EARLY AFTERNOON AS A WARM FRONT
LIFTS NORTHWARD ACROSS THE AREA. HOWEVER...WILL CONTINUE TO SEE
SOME PERIODIC HIGH CLOUDS OVER THE CWA THROUGH THE AFTERNOON.
CURRENT TRENDS SHOWING THAT FORECAST HIGH TEMPERATURES ARE ON
TARGET...WITH THE ONLY AREA OF CONCERN AROUND PEORIA AND
BLOOMINGTON WHERE ABOUT AN INCH OF SNOW STILL REMAINS ON THE
GROUND. WIND GUSTS WILL BE INCREASING THROUGH THE DAY...AS A
STRONG SOUTHWEST LOW-LEVEL JET AROUND 45 KNOTS STARTS MIXING DOWN
WHEN THE SUNSHINE BECOMES MORE DOMINANT.
UPDATED GRIDS HAVE BEEN SENT TO INCORPORATE THE RECENT HOURLY
TRENDS. WILL SEND OUT A ZONE UPDATE CLOSER TO NOON...PRIMARILY TO
UPDATE THE SKY TRENDS.
GEELHART
&&
.AVIATION...
ISSUED 1122 AM CST MON JAN 30 2012
BULK OF THE MID-LEVEL CLOUDINESS HAS MOVED NORTHEAST OF THE TAF
SITES LATE THIS MORNING. THE LOW-LEVEL JET HAS BEGUN MIXING TOWARD
THE SURFACE...AS EVIDENCED BY DECREASING SPEEDS ON THE LOWEST
GATES OF THE 88D/WIND PROFILER NETWORK AND AREA AMDAR SOUNDINGS...
WITH SURFACE GUSTS OF 20-25 KNOTS BECOMING MORE COMMON OVER THE
LAST HOUR OR TWO. THINK THIS TREND WILL CONTINUE THROUGH THE
AFTERNOON...SO HAVE REMOVED LLWS MENTION FOR THE AFTERNOON.
HOWEVER...SOUNDINGS ARE PROMINENTLY WITH LLWS RETURNING SHORTLY
AFTER SUNSET...AND LASTING MOST OF THE NIGHT...SO WILL KEEP THE
LLWS ALREADY IN THE TAFS FOR THAT PERIOD.
LOW-LEVEL MOISTURE WILL BE SURGING NORTHEASTWARD LATE IN THE
NIGHT...AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. WILL
MENTION CEILINGS IN THE 3500 FOOT RANGE FOR THE LATTER PORTIONS OF
THE PERIOD. HOWEVER...HAVE SOME CONCERNS FOR POTENTIAL MVFR
CONDITIONS AROUND KPIA/KBMI...WHERE THERE WILL BE SOME MELTING
SNOW TODAY TO ADD MOISTURE TO THE LOWER LEVELS. SOUNDINGS OFF THE
NAM MODEL HINT AT SOME CEILINGS AS LOW AS 1000 FEET FOR A FEW
HOURS TUESDAY MORNING. CONFIDENCE IS NOT PARTICULARLY HIGH AT THIS
TIME...SO WILL ONLY MENTION A SCATTERED LAYER AROUND THAT LEVEL
FOR NOW AND CONTINUE TO MONITOR.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 251 AM CST MON JAN 30 2012
MAIN CONCERNS WITH THIS FORECAST PACKAGE WILL BE RAIN CHANCES LATE
TUESDAY...THEN POTENTIAL FOR WINTRY PRECIP BY NEXT WEEKEND.
08Z SURFACE ANALYSIS SHOWS WARM FRONT EXTENDING FROM THE NORTHERN
PLAINS INTO THE OHIO RIVER VALLEY. TEMPERATURES AHEAD OF THE
BOUNDARY ACROSS THE UPPER MIDWEST/GREAT LAKES ARE CURRENTLY IN THE
TEENS AND 20S...WHILE READINGS BEHIND THE FRONT ACROSS THE CENTRAL
PLAINS ARE IN THE 40S. ALOFT...ZONAL FLOW PATTERN CONTINUES TO
DOMINATE ACROSS THE CONUS...KEEPING THE BITTERLY COLD POLAR AIRMASS
BOTTLED UP WELL TO THE NORTH ACROSS ALASKA AND NORTHERN CANADA.
SHORT TERM...TODAY THROUGH WEDNESDAY
WARM FRONT WILL LIFT NORTHWARD TODAY...ALLOWING WINDS TO VEER TO THE
SOUTHWEST AND MUCH WARMER AIR TO FLOW INTO CENTRAL ILLINOIS. BAND OF
MID-LEVEL CLOUDINESS ASSOCIATED WITH THE FRONT WILL ENSURE A MOSTLY
CLOUDY MORNING...HOWEVER SKIES WILL BECOME MOSTLY SUNNY BY
AFTERNOON. THANKS TO AMPLE LATE DAY SUNSHINE AND SOUTHWESTERLY WINDS
GUSTING TO BETWEEN 25 AND 30 MPH...HIGH TEMPS WILL SOAR WELL INTO
THE 50S.
SHORT-WAVE TROUGH CURRENTLY EVIDENT ON WATER VAPOR IMAGERY OVER THE
PACIFIC NORTHWEST WILL TRACK EASTWARD ALONG THE US/CANADIAN
BORDER...ARRIVING IN THE NORTHERN GREAT LAKES BY TUESDAY EVENING.
TRAILING COLD FRONT WILL REMAIN WEST OF THE MISSISSIPPI RIVER
THROUGH THE DAY TUESDAY...ALLOWING SOUTHWESTERLY FLOW TO CONTINUE
ACROSS CENTRAL ILLINOIS. INCREASING FETCH OF LOW-LEVEL MOISTURE OFF
THE WESTERN GULF OF MEXICO WILL RESULT IN CLOUDY SKIES...HOWEVER
CONTINUED WAA WILL ALLOW TEMPS TO RISE A FEW DEGREES HIGHER THAN
TODAY...WITH AFTERNOON HIGHS TOPPING THE 60 DEGREE MARK ACROSS MOST
LOCATIONS SOUTH OF THE I-72 CORRIDOR. MODELS TRY TO SQUEEZE OUT SOME
LIGHT QPF DURING THE AFTERNOON...HOWEVER FORECAST SOUNDINGS DO NOT
FULLY MOISTEN THROUGHOUT THE PROFILE...SO DO NOT THINK WIDESPREAD
PRECIP IS LIKELY. HAVE INCLUDED JUST A SLIGHT CHANCE POP ACROSS THE
WESTERN KILX CWA TUESDAY AFTERNOON AS THE FRONT APPROACHES FROM THE
WEST. DEEPER MOISTURE GRADUALLY ARRIVES FROM THE SOUTH TUESDAY
EVENING...RESULTING IN SHOWERS INCREASING IN AREAL COVERAGE AHEAD OF
THE COLD FRONT...MAINLY ACROSS EAST-CENTRAL AND SOUTHEAST ILLINOIS.
HAVE THEREFORE HIT RAIN CHANCES HARDEST ALONG AND EAST OF
I-57...WHERE LIKELY POPS ARE IN ORDER. FURTHER WEST...RAIN CHANCES
STEADILY DECREASE...WITH ONLY SLIGHT CHANCES ACROSS THE ILLINOIS
RIVER VALLEY.
COLD FRONT WILL SETTLE FURTHER SOUTHWARD ON WEDNESDAY...AS SURFACE
RIDGE BUILDS IN FROM THE NORTHWEST. SHORT-WAVE TROUGH TRACKING
EASTWARD OUT OF THE PLAINS WILL LIKELY ENHANCE PRECIP ALONG/NORTH OF
THE BOUNDARY...HOWEVER IT APPEARS ANY RAIN WILL STAY SOUTH OF
ILLINOIS ACROSS THE OHIO RIVER VALLEY. AS A RESULT...HAVE GONE WITH
A DRY FORECAST ON WEDNESDAY...WITH SLIGHTLY COOLER TEMPS IN THE
UPPER 40S/LOWER 50S.
LONG TERM...THURSDAY THROUGH SUNDAY
AFTER SOME RECENT MODEL DISCREPANCIES...00Z 30 JAN SUITE HAS COME
INTO GOOD AGREEMENT FOR THURSDAY/FRIDAY TIME FRAME. WITH BAROCLINIC
ZONE EXPECTED TO BE WELL SOUTH OF THE REGION...DRY WEATHER WILL
PREVAIL THROUGH THE END OF THE WORK WEEK. AFTER THAT...MODEL
SOLUTIONS DIVERGE SOMEWHAT FOR THE WEEKEND AS STRONG RIDGE BUILDS
OVER THE WESTERN CONUS AND CORRESPONDING TROUGH DEVELOPS ACROSS THE
EAST. STILL LOOKS LIKE A MARKED COOLING TREND ARRIVING BY SATURDAY
AND SUNDAY...WITH TEMPS RETURNING TO NEAR NORMAL IN THE 30S. MAIN
QUESTION WILL BE HOW FAR NORTH A DEVELOPING SURFACE LOW WILL
TRACK...AND WILL IT BRING SNOW TO PARTS OF CENTRAL ILLINOIS. GFS IS
THE FURTHEST NORTH WITH THE LOW...SPREADING SNOW ACROSS THE SOUTHERN
TWO-THIRDS OF THE KILX CWA FRIDAY NIGHT AND SATURDAY. CANADIAN/ECMWF
ARE A BIT FURTHER SOUTH...BUT STILL BRING PRECIP INTO AT LEAST THE
FAR SE. STILL QUITE A BIT OF TIME TO WORK OUT THE DETAILS...BUT FOR
NOW...IT APPEARS COLDER WEATHER AND SOME SNOW ARE ON THE WAY FOR NEXT
WEEKEND.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1000 AM CST MON JAN 30 2012
.DISCUSSION...
ISSUED 1000 AM CST MON JAN 30 2012
AREA OF MID-LEVEL CLOUDINESS IS NOW GENERALLY NORTH OF A MACOMB TO
EFFINGHAM LINE. LATEST RUC GUIDANCE SHOWING THESE TO RECEDE
ACROSS THE NORTHERN CWA THROUGH EARLY AFTERNOON AS A WARM FRONT
LIFTS NORTHWARD ACROSS THE AREA. HOWEVER...WILL CONTINUE TO SEE
SOME PERIODIC HIGH CLOUDS OVER THE CWA THROUGH THE AFTERNOON.
CURRENT TRENDS SHOWING THAT FORECAST HIGH TEMPERATURES ARE ON
TARGET...WITH THE ONLY AREA OF CONCERN AROUND PEORIA AND
BLOOMINGTON WHERE ABOUT AN INCH OF SNOW STILL REMAINS ON THE
GROUND. WIND GUSTS WILL BE INCREASING THROUGH THE DAY...AS A
STRONG SOUTHWEST LOW-LEVEL JET AROUND 45 KNOTS STARTS MIXING DOWN
WHEN THE SUNSHINE BECOMES MORE DOMINANT.
UPDATED GRIDS HAVE BEEN SENT TO INCORPORATE THE RECENT HOURLY
TRENDS. WILL SEND OUT A ZONE UPDATE CLOSER TO NOON...PRIMARILY TO
UPDATE THE SKY TRENDS.
GEELHART
&&
.AVIATION...
ISSUED 515 AM CST MON JAN 30 2012
WIND WILL BE THE MAIN ISSUE THIS TAF PERIOD. INITIAL WINDS SOUTH TO
SOUTHEAST 10-15 KT WILL INCREASE FROM THE SOUTH-SOUTHWEST WITH
SUSTAINED 16-21 KT AND GUSTS 25-30 KT. MODEL SOUNDINGS INDICATE 2K
FT WINDS 25045 KT AS WARM FRONT PASSES THROUGH THIS MORNING AND
MAINTAINS THESE SPEEDS...SO WILL INDICATE LLWS THROUGH THE PERIOD
ALTHOUGH IT MIGHT BE MARGINAL DURING PEAK MIXING TIME IN THE EARLY
AFTERNOON. ONLY CLOUDS WILL BE SCT-BKN ALTOCU AND SCT-BKN HIGH
CLOUDS.
04
&&
.PREV DISCUSSION...
ISSUED 251 AM CST MON JAN 30 2012
MAIN CONCERNS WITH THIS FORECAST PACKAGE WILL BE RAIN CHANCES LATE
TUESDAY...THEN POTENTIAL FOR WINTRY PRECIP BY NEXT WEEKEND.
08Z SURFACE ANALYSIS SHOWS WARM FRONT EXTENDING FROM THE NORTHERN
PLAINS INTO THE OHIO RIVER VALLEY. TEMPERATURES AHEAD OF THE
BOUNDARY ACROSS THE UPPER MIDWEST/GREAT LAKES ARE CURRENTLY IN THE
TEENS AND 20S...WHILE READINGS BEHIND THE FRONT ACROSS THE CENTRAL
PLAINS ARE IN THE 40S. ALOFT...ZONAL FLOW PATTERN CONTINUES TO
DOMINATE ACROSS THE CONUS...KEEPING THE BITTERLY COLD POLAR AIRMASS
BOTTLED UP WELL TO THE NORTH ACROSS ALASKA AND NORTHERN CANADA.
SHORT TERM...TODAY THROUGH WEDNESDAY
WARM FRONT WILL LIFT NORTHWARD TODAY...ALLOWING WINDS TO VEER TO THE
SOUTHWEST AND MUCH WARMER AIR TO FLOW INTO CENTRAL ILLINOIS. BAND OF
MID-LEVEL CLOUDINESS ASSOCIATED WITH THE FRONT WILL ENSURE A MOSTLY
CLOUDY MORNING...HOWEVER SKIES WILL BECOME MOSTLY SUNNY BY
AFTERNOON. THANKS TO AMPLE LATE DAY SUNSHINE AND SOUTHWESTERLY WINDS
GUSTING TO BETWEEN 25 AND 30 MPH...HIGH TEMPS WILL SOAR WELL INTO
THE 50S.
SHORT-WAVE TROUGH CURRENTLY EVIDENT ON WATER VAPOR IMAGERY OVER THE
PACIFIC NORTHWEST WILL TRACK EASTWARD ALONG THE US/CANADIAN
BORDER...ARRIVING IN THE NORTHERN GREAT LAKES BY TUESDAY EVENING.
TRAILING COLD FRONT WILL REMAIN WEST OF THE MISSISSIPPI RIVER
THROUGH THE DAY TUESDAY...ALLOWING SOUTHWESTERLY FLOW TO CONTINUE
ACROSS CENTRAL ILLINOIS. INCREASING FETCH OF LOW-LEVEL MOISTURE OFF
THE WESTERN GULF OF MEXICO WILL RESULT IN CLOUDY SKIES...HOWEVER
CONTINUED WAA WILL ALLOW TEMPS TO RISE A FEW DEGREES HIGHER THAN
TODAY...WITH AFTERNOON HIGHS TOPPING THE 60 DEGREE MARK ACROSS MOST
LOCATIONS SOUTH OF THE I-72 CORRIDOR. MODELS TRY TO SQUEEZE OUT SOME
LIGHT QPF DURING THE AFTERNOON...HOWEVER FORECAST SOUNDINGS DO NOT
FULLY MOISTEN THROUGHOUT THE PROFILE...SO DO NOT THINK WIDESPREAD
PRECIP IS LIKELY. HAVE INCLUDED JUST A SLIGHT CHANCE POP ACROSS THE
WESTERN KILX CWA TUESDAY AFTERNOON AS THE FRONT APPROACHES FROM THE
WEST. DEEPER MOISTURE GRADUALLY ARRIVES FROM THE SOUTH TUESDAY
EVENING...RESULTING IN SHOWERS INCREASING IN AREAL COVERAGE AHEAD OF
THE COLD FRONT...MAINLY ACROSS EAST-CENTRAL AND SOUTHEAST ILLINOIS.
HAVE THEREFORE HIT RAIN CHANCES HARDEST ALONG AND EAST OF
I-57...WHERE LIKELY POPS ARE IN ORDER. FURTHER WEST...RAIN CHANCES
STEADILY DECREASE...WITH ONLY SLIGHT CHANCES ACROSS THE ILLINOIS
RIVER VALLEY.
COLD FRONT WILL SETTLE FURTHER SOUTHWARD ON WEDNESDAY...AS SURFACE
RIDGE BUILDS IN FROM THE NORTHWEST. SHORT-WAVE TROUGH TRACKING
EASTWARD OUT OF THE PLAINS WILL LIKELY ENHANCE PRECIP ALONG/NORTH OF
THE BOUNDARY...HOWEVER IT APPEARS ANY RAIN WILL STAY SOUTH OF
ILLINOIS ACROSS THE OHIO RIVER VALLEY. AS A RESULT...HAVE GONE WITH
A DRY FORECAST ON WEDNESDAY...WITH SLIGHTLY COOLER TEMPS IN THE
UPPER 40S/LOWER 50S.
LONG TERM...THURSDAY THROUGH SUNDAY
AFTER SOME RECENT MODEL DISCREPANCIES...00Z 30 JAN SUITE HAS COME
INTO GOOD AGREEMENT FOR THURSDAY/FRIDAY TIME FRAME. WITH BAROCLINIC
ZONE EXPECTED TO BE WELL SOUTH OF THE REGION...DRY WEATHER WILL
PREVAIL THROUGH THE END OF THE WORK WEEK. AFTER THAT...MODEL
SOLUTIONS DIVERGE SOMEWHAT FOR THE WEEKEND AS STRONG RIDGE BUILDS
OVER THE WESTERN CONUS AND CORRESPONDING TROUGH DEVELOPS ACROSS THE
EAST. STILL LOOKS LIKE A MARKED COOLING TREND ARRIVING BY SATURDAY
AND SUNDAY...WITH TEMPS RETURNING TO NEAR NORMAL IN THE 30S. MAIN
QUESTION WILL BE HOW FAR NORTH A DEVELOPING SURFACE LOW WILL
TRACK...AND WILL IT BRING SNOW TO PARTS OF CENTRAL ILLINOIS. GFS IS
THE FURTHEST NORTH WITH THE LOW...SPREADING SNOW ACROSS THE SOUTHERN
TWO-THIRDS OF THE KILX CWA FRIDAY NIGHT AND SATURDAY. CANADIAN/ECMWF
ARE A BIT FURTHER SOUTH...BUT STILL BRING PRECIP INTO AT LEAST THE
FAR SE. STILL QUITE A BIT OF TIME TO WORK OUT THE DETAILS...BUT FOR
NOW...IT APPEARS COLDER WEATHER AND SOME SNOW ARE ON THE WAY FOR NEXT
WEEKEND.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
306 PM CST MON JAN 30 2012
.DISCUSSION...
21Z WATER VAPOR IMAGERY SHOWS A SHORTWAVE MOVING ACROSS MT AND ID
AND INTO THE NORTHERN PLAINS. MEANWHILE SURFACE OBS SHOW A BROAD
TROUGH OF LOW PRESSURE FROM THE SOUTHERN HIGH PLAINS INTO THE
NORTHERN PLAINS. THIS HAS ALLOWED FOR HIGHS TO WARM INTO THE MID
AND UPPER 60S WHILE DEWPOINTS INCREASED INTO THE 30S ACROSS THE
FORECAST AREA.
FOR TONIGHT AND TUESDAY...THE MAIN CONCERN IS WHAT THE STRONG
MOISTURE ADVECTION WILL DO OVERNIGHT AND EARLY TUESDAY MORNING.
MODELS ARE KEEPING THE FORCING FROM THE NORTHERN PLAINS SHORTWAVE TO
THE NORTH OF THE FORECAST AREA...AND A DECENT ELEVATED MIXED LAYER
IS PROGGED TO KEEP THE BOUNDARY LAYER CAPPED. THEREFORE CHANCES FOR
MEASURABLE PRECIP LOOK PRETTY SLIM AS A COLD FRONT ASSOCIATED WITH
THE NORTHERN PLAINS WAVE PUSHES THROUGH THE AREA DURING THE DAY
TUESDAY. HOWEVER LOW LEVEL MOISTURE IS EXPECTED TO CONTINUE TO
ADVECT NORTH INTO EASTERN KS THROUGH THE NIGHT WITH READINGS
POSSIBLY IN THE MID 40S BY SUNRISE. THE LATEST RUC AND NAM FORECAST
SOUNDINGS CONTINUE TO SHOW THE BOUNDARY LAYER SATURATING BY 12Z
AHEAD OF THE SFC COLD FRONT. THERE ALSO APPEARS TO BE SOME WEAK LIFT
ON THE 285K ISENTROPIC SFC AHEAD OF THE FRONT. THEREFORE DID NOT SEE
ANY REASON TO CHANGE THE MENTION OF FOG AND DRIZZLE FROM THE
PREVIOUS FORECAST. WINDS SHOULD STAY UP FAVORING MORE STRATUS THAN
FOG SO DO NOT ANTICIPATE THERE BEING A SEVERE RESTRICTION TO
VISIBILITIES AT THIS TIME. OVERNIGHT LOWS WILL BE MILD DUE TO THE
WARM AIR AND MOISTURE MOVING NORTH. FOR HIGHS TUESDAY...THE MODELS
ARE MIXING THE BOUNDARY LAYER TO AT LEAST 900 MB WITH NOT A WHOLE
LOT OF COLD AIR BEHIND THE FRONT. BECAUSE OF THIS...HAVE BUMPED HIGHS
UP INTO THE UPPER 50S AND AROUND 60 THINKING THERE SHOULD BE ENOUGH
INSOLATION IN THE AFTERNOON TO HELP TEMPS WARM.
WOLTERS
FOR TUESDAY NIGHT THROUGH THURSDAY...MID AND HIGH LEVEL CLOUDS COULD
BE RATHER PERSISTENT...WITH A BRIEF BREAK LATE WEDNESDAY...WITH MID
AND LOW LEVELS STILL ON THE DRY SIDE BEHIND THE COLD FRONT. AS
MENTIONED ABOVE...AIRMASS COMING IN BEHIND IS ONLY SLIGHTLY COOLER
THAN TUESDAY...BUT MIXING WILL BE MORE LIMITED FOR WEDNESDAY SO
EXPECT SOMEWHAT COOLER TEMPS. FAVORING THE MORE-AGREED-UPON SLOWER
MODELS OVER THE NAM FOR THURSDAY...WITH WEAK MID LEVEL WARM AIR
ADVECTION BRINGING IN DEEPENING HIGH CLOUDS THURSDAY AFTERNOON AS
THE WESTERN UPPER TROF DIGS INTO THE ROCKIES. TEMPS IN THE LOW TO
MID 50S STILL EXPECTED UNDER EASTERLY WINDS.
MEDIUM RANGE MODELS CONTINUE TO COME TOGETHER WITH THE UPPER TROF AT
LEAST PARTIALLY CUTTING OFF FROM THE FLOW FOR THE LATE WEEK AND
WEEKEND PERIODS. OF COURSE ANY SPECIFICS ARE FAR FROM CERTAIN...BUT
PRECIPITATION FALLING ON MOST LOCATIONS AT LEAST ONCE IN THIS PERIOD
IS BECOMING A GOOD BET. STILL APPEARS TEMPS MAY BE COLD ENOUGH TO
SUPPORT SOME SNOW...BUT AGAIN MUCH TO BE DETERMINED HERE. OVERALL
TEMPS NOT EXPECTED TO STRAY FAR FROM EARLY FEBRUARY NORMALS.
65
&&
.AVIATION...
DRY MID LEVELS AND NO REAL FORCING WILL LEAD TO VFR CONDITIONS
TODAY. SFC OBS ACROSS THE SOUTHERN PLAINS SHOWS THE MOISTURE
ADVECTION IS UNDERWAY. DUE TO GOOD CONSISTENCY IN THE MODELS SHOWING
THE BOUNDARY LAYER SATURATING EARLY TUESDAY MORNING...HAVE GONE
AHEAD AND INTRODUCED SOME MVFR CIGS IN THE TAFS FOR TOP AND FOE. MHK
LOOKS TO BE ON THE WESTERN EDGE OF THE LOW LEVEL TONGUE OF
MOISTURE. LATER SHIFTS WILL NEED TO LOOK AND SEE IF THE STRATUS
COMES IN BELOW 1 KFT.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
852 PM EST TUE JAN 31 2012
.SYNOPSIS...
A COLD FRONT, MOVING SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY
LATE TONIGHT AND WEDNESDAY, WILL BRING SHOWERS. TEMPERATURES
BEHIND THE FRONT WILL BE COOLER BUT STILL ABOVE NORMAL.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
MID EVENING UPDATE TO ADJUST POPS TOWARD RADAR TRENDS AS SHOWERS
ARE EXPANDING ACROSS LOWER OHIO VALLEY AND WILL SPREAD ACROSS OUR
REGION OVERNIGHT. NO OTHER SIGNIFICANT CHANGES AND PREVIOUS
DISCUSSION FOLLOWS...
RECENT NAM AND SREF MODEL OUTPUT SHOW THE COLD FRONT WILL BE
PRECEDED BY TWO BANDS OF SHOWERS, WHICH WILL MOVE THROUGH THE
UPPER OHIO VALLEY LATER TONIGHT AND WEDNESDAY MORNING. THERE CAN BE
LINGERING SHOWERS ACROSS THE WV- MD-PA MOUNTAINS INTO LATE
AFTERNOON.
BECAUSE OF THE MILD PREFRONTAL SOUTHWEST WINDS, FORECASTED
TEMPERATURES, USING RECENT GFS LAMP AND MOS, TO BE AS MUCH AS 20-25
DEGREES WARMER THAN NORMAL TONIGHT.
WESTERLY JETSTREAM ALOFT WILL MINIMIZE STRENGTH OF POST FRONTAL
COOLING WEDNESDAY. HENCE, AS SUGGESTED BY GFS AND NAM MOS, EXPECT
HIGHS WEDNESDAY AFTERNOON TO STILL BE 15-20 DEGREES WARMER THAN
NORMAL.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW A WESTERLY JETSTREAM
ALOFT THIS PERIOD, WHICH WILL RESTRICT THE STRENGTH OF ANY COLD
AIR INTRUSION. A WEAK TROUGH PASSING THROUGH THE UPPER OHIO
VALLEY THURSDAY SHOULD ENSURE MOSTLY CLOUDY SKIES THROUGH THE
PERIOD. HOWEVER, EXPECT LITTLE IF ANY PRECIPITATION, EVEN ACROSS
THE WINDWARD MOUNTAIN SLOPES.
HAVE FORECASTED TEMPERATURES TO BE COOLER THAN WEDNESDAY, BUT
STILL CAN BE 10 DEGREES WARMER THAN NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MORE SO THAN THE LAST FEW DAYS...THE DETERMINISTIC MODELS AND
ENSEMBLE MEANS HAVE BEGUN TO SUGGEST VERY SIMILAR SCENARIOS IN
EJECTION OF THE 500HPA LOW THROUGH THE CENTRAL U.S AND TOWARDS THE
REGION. THE MODELS THAT YESTERDAY SUGGESTED A NEARLY STATIONARY
CUTOFF LOW OVER THE EASTERN ROCKIES...HAVE SPED UP TO A CLOSER
GEFS/GFS SOLUTION THAT HAS BE PREVALENT FOR A FEW DAYS. THE SPLIT
FLOW CONTINUES TO MAKE SOME OF THE FORECAST VARIABLES DIFFICULT
HOWEVER...ESPECIALLY IN REGARDS TO TIMING AND LOCATION OF THE
SURFACE LOW AS IT CROSSES THE OHIO VALLEY.
CONTINUED TO FOLLOW CLOSELY TO HPC GUIDANCE, BUT TOOK THE MOST RECENT
RUNS OF THE GEFS...GFS...AND ECMWF INTO ACCOUNT. KEPT CHANCE POPS IN
THE FORECAST SATURDAY THROUGH SUNDAY AS THE LOW CROSSES. USED A
BLEND OF HPC AND TO A GREATER EXTENT MEX GUIDANCE THROUGH TUESDAY.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL CONTINUE THIS EVE BUT WL BE MARRED BY
INCREASING...AND LOWERING MID LVL CLDINESS AS STRNG...WARM...MOIST
ADVCTN CONTS IN ADVN OF STRNG LOW PRES MOVG ACRS THE NRN LAKES.
-SHRA ACTIVITY WL ALSO BE ON THE INCRS...BUT RESTRICTIONS ARE NOT
ANTICIPATED UNTIL THE LLVLS GET CLOSER TO SATURATION LTR TNGT. MVFR
IS CONFIDENTLY FORECAST IN THE POST MIDNGT PD...AND SHOULD DOMINATE
AREA TAFS UNTIL FRONTAL PASSAGE LTR ON WEDNESDAY MRNG.
ALSO OF CONCERN IS THE INCREASING INDICATIONS OF MORE LLWS AS
PROGGED VIA THE LATEST NAM AND RUC MDL SOUNDINGS. HAVE THUS ADDED
THIS POTENTIAL FOR THE EVE TAF ISSUANCES WITH NR 50 KTS FORECAST
ABOVE THE INVERSION LEVEL...I.E. ARND 2 KFT...AGAIN UNTIL FRONTAL
PASSAGE LTR ON WED MRNG.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
LATEST DETERMINISTIC MDL SOLNS INDICATE THAT LOW PRES MOVING ALNG
FRONTAL BOUNDARY SHOULD PASS SUFFICIENTLY SOUTH OF UPR OH VALLEY
TERMINALS TO PRECLUDE WIDESPREAD RESTRICTIONS ON WED NGT. SFC WND
WL SHIFT TO THE NW IN THE WAKE OF THAT SYS ON THURSDAY WITH COLD
ADVCTN SPAWNING SOME LAKE/UPSLOPE ENHANCED STRATOCUMULUS. VFR
CONDITIONS ARE EXPECTED TO RTN FRIDAY...BUT ANOTHER LOW MAY DEGRADE
CONDTIONS AGAIN FOR THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
313 PM EST MON JAN 30 2012
.SYNOPSIS...
WITH A WARM FRONT HAVING GONE NORTH TO THE GREAT LAKES, EXPECT DRY
AND MILD CONDITIONS TONIGHT AND TUESDAY. A WEAK COLD FRONT, COMING
SOUTHEAST FROM THE CANADIAN ROCKIES, WILL BRING RAIN SHOWERS LATE
TUESDAY NIGHT AND WEDNESDAY, WITH TEMPERATURES RETURNING TO
SEASONABLE LEVELS.
&&
.NEAR TERM /THROUGH TUESDAY/...
RECENT SATELLITE DATA SHOWS THICK CLOUDS, ASSOCIATED WITH A
NORTHWARD-MOVING WARM FRONT, PASSING EASTWARD ACROSS THE I-80
CORRIDOR THIS EVENING, SO HAVE MAINTAINED MENTION OF ISOLATED
FLURRIES FOR THAT AREA.
THE REST OF THE UPPER OHIO VALLEY CAN EXPECT CLOUDS TO DECREASE
OVERNIGHT. WITH THE UPPER OHIO VALLEY IN THE SO-CALLED WARM SECTOR
DAYTIME TUESDAY, EXPECT THERE TO MORE FREQUENT PERIODS OF
SUNSHINE.
FORECASTED TEMPERATURES FOR TONIGHT, USING BLEND OF HRRR AND GFS
LAMP MODEL OUTPUT. THIS SHOWED TEMPERATURES WILL ONLY DROP A
COUPLE DEGREES OVERNIGHT, MAKING LOWS AT LEAST 10 DEGREES WARMER
THAN NORMAL.
FOR TEMPERATURES TUESDAY, RELIED MORE ON NAM AND GFS MOS OUTPUT
WHICH SHOWED AFTERNOON HIGHS CAN BE UP TO 15-20 DEGREES WARMER
THAN NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW A LOW PRESSURE SYSTEM,
COMING SOUTHEAST FROM ALBERTA, PUSHING A COLD FRONTAL BAND OF SHOWERS
THROUGH THE UPPER OHIO VALLEY LATE TUESDAY NIGHT AND WEDNESDAY
MORNING. IN THE PREFRONTAL SOUTHWEST FLOW, BLEND OF GFS AND NAM
MOS SHOWED LOW TEMPERATURES TUESDAY NIGHT CAN BE WARMER THAN
NORMAL JANUARY HIGHS.
WITH THE UPPER LEVEL JETSTREAM BECOMING MORE WESTERLY MID-WEEK,
EXPECT A WEAK POST FRONTAL COOL DOWN WEDNESDAY AFTERNOON. HENCE FORECASTED
TEMPERATURES WEDNESDAY, AGAIN USING BLEND OF GFS AND NAM MOS, TO
YIELD EARLY AFTERNOON HIGHS UP TO 15 DEGREES WARMER THAN NORMAL.
THERE CAN BE LINGERING COLD POOL STRATOCUMULUS WEDNESDAY NIGHT AND THURSDAY,
WITH PERHAPS A MIX OF LIGHT RAIN AND SNOW SHOWERS ACROSS ON THE
WINDWARD SLOPES OF THE MOUNTAINS.
GFS AND NAM MOS SHOWED TEMPERATURES THURSDAY NOT AS WARM AS
WEDNESDAY, BUT STILL 5-8 DEGREES WARMER THAN NORMAL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE FORECAST FOR THIS PERIOD REMAINS DIFFICULT DESPITE COMMON
LONG WAVE PATTERN SIMILARITIES BETWEEN THE DETERMINISTIC MODELS.
AS HAS BEEN THE CASE OVER THE LAST FEW DAYS...A DEEP POSITIVELY
TILTED TROUGH WILL DEVELOP OVER THE EASTERN EDGE OF THE
ROCKIES...WITH A STRONG FOLD-OVER RIDGE OVER THE WESTERN U.S.
WHERE THE MODELS DIFFER IS IN TIMING. SOME OF THE MODELS SUGGEST
THAT THE LOW WILL REMAIN ESSENTIALLY CUTOFF FROM THE REST OF THE
FLOW WHILE OTHERS EJECT THE LOW EASTWARD FAIRLY QUICKLY. THE SPLIT
FLOW PATTERN IS WHAT IS MAKING THE SMALLER SHORTWAVE TIMING AND
PLACEMENT DIFFICULT.
HAVE OPTED TO REMAIN CLOSEST TO HPC AND IN TURN ACCOUNT FOR GENERAL
SHORTWAVE PATTERN SIMILARITIES BETWEEN THE 00Z ECMWF AND 06/12Z GFS
THROUGH THE PERIOD. MAINTAINED ONLY LOW CHANCE POPS THROUGH MOST OF
THE PERIOD WITH SUCH MODEL UNCERTAINTY AND TEMPERATURES CLOSE TO AN
HPC/MEX BLEND.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL THROUGHOUT THE TAF PERIOD AS HIGH
PRESSURE BUILDS IN FROM THE SOUTH TODAY. SOME MID-LEVEL CLOUDS
ASSOCIATED WITH A WARM FRONT WILL CROSS THE AREA THIS AFTERNOON AND
TONIGHT.
WINDS MAY GUSTS OUT OF THE S-SW TO 20KTS THIS AFTERNOON BUT
GENERALLY JUST MAINTAINED HIGHER WIND SPEEDS AT ALL SITES. WINDS
WILL DIMINISH TONIGHT. HOWEVER...MENTIONED LOW LEVEL WIND SHEAR AS
NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER WITH WINDS INCREASING
TO OVER 45 KTS ABOVE 2 KFT AGL.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
VFR CONDITIONS WILL CONTINUE TUESDAY EVENING. A COLD FRONTAL BAND
OF SHOWERS WILL PROVIDE RESTRICTIONS LATE TUESDAY NIGHT INTO
WEDNESDAY MORNING. POST FRONTAL STRATOCUMULUS MAY CAUSE CEILING
RESTRICTIONS TO LINGER INTO THURSDAY. VFR CONDITIONS WILL RETURN TO
THE TERMINALS ON FRIDAY AS HIGH PRESSURE BUILDS INTO THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1200 PM EST MON JAN 30 2012
.SYNOPSIS...
EASTBOUND HIGH PRESSURE, WILL PROVIDE DRY CONDITIONS AND
SEASONABLE TEMPERATURES TODAY, BUT A PLEASANT WARM UP ON TUESDAY. A
COLD FRONT WILL BRING SHOWERS LATE TUESDAY NIGHT AND WEDNESDAY
WITH TEMPERATURES RETURNING TO SEASONABLE LEVELS.
&&
.NEAR TERM /THROUGH TUESDAY/...
PER RECENT RADAR, SATELLITE, AND SURFACE DATA, COUPLED WITH HRRR
AND NAM MODEL OUTPUT, HAVE DECREASED POTENTIAL FOR WARM FRONTAL
PRECIPITATION ACROSS THE I-80 CORRIDOR TO NO MORE THAN ISOLATED
FLURRIES LATE THIS AFTERNOON AND EARLY TONIGHT.
THE REST OF THE UPPER OHIO VALLEY CAN ENTERTAIN AN INCREASE IN
HIGH CLOUDS, BUT STILL EXPECT PARTLY SUNNY CONDITIONS THIS
AFTERNOON. WITH THE UPPER OHIO VALLEY IN THE SO-CALLED WARM SECTOR
DAYTIME TUESDAY, EXPECT THERE TO MORE FREQUENT PERIODS OF
SUNSHINE.
FORECASTED TEMPERATURES USING BLEND OF HRRR AND GFS LAMP MODEL
OUTPUT FOR THIS AFTERNOON, WHICH YIELDED NEAR NORMAL VALUES.
RELIED MORE ON NAM AND GFS MOS OUTPUT FOR TONIGHT AND DAYTIME
TUESDAY, WHICH SHOWED VALUES UP TO 15-20 DEGREES WARMER THAN
NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW A LOW PRESSURE SYSTEM,
COMING SOUTHEAST FROM ALBERTA, PUSHING A COLD FRONTAL BAND OF SHOWERS
THROUGH THE UPPER OHIO VALLEY LATE TUESDAY NIGHT AND WEDNESDAY
MORNING. IN THE PREFRONTAL SOUTHWEST FLOW, BLEND OF GFS AND NAM
MOS SHOW LOWS TEMPERATURES TUESDAY NIGHT CAN BE WARMER THAN NORMAL
JANUARY HIGHS.
WITH THE UPPER LEVEL JETSTREAM BECOMING MORE WESTERLY MID-WEEK,
EXPECT A WEAK POST FRONTAL COOL DOWN WEDNESDAY AFTERNOON. HENCE FORECASTED
TEMPERATURES WEDNESDAY, AGAIN USING BLEND OF GFS AND NAM MOS, TO
YIELD EARLY AFTERNOON HIGHS UP TO 15 DEGREES WARMER THAN NORMAL.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS WAS THE CASE YESTERDAY...MODELS CONTINUE TO HAVE TROUBLE
RESOLVING THE PLACEMENT AND TIMING OF SYSTEMS DURING THIS PERIOD.
WHILE ALL THE MODELS CONTINUE TO SUGGEST A DEEPENING LONG WAVE
PATTERN...WITH A STRONG RIDGE OVER THE WESTERN U.S AND A DEEP TROUGH
OVER THE EASTERN U.S...THE SHORTWAVE PATTERN AND IN TURN LOW
PLACEMENT REMAINS INCONSISTENT FROM RUN TO RUN.
IN GENERAL...MODELS SUGGEST THAT THE COLD FRONT...PROGGED TO CROSS
THE OHIO VALLEY DURING THE DAY WEDNESDAY...WILL HANG UP AROUND THE
MASON-DIXON LINE AND EVENTUALLY MOVE NORTHWARD AS A WARM FRONT. THE
QUESTION IS WHEN AND HOW FAR NORTH WILL THE SYSTEM MAKE IT AT THIS
POINT.
CONTINUED TO REMAIN CLOSE TO HPC GUIDANCE WITH ONLY LOW CHANCE POPS
THROUGH MOST OF THE PERIOD WITH SUCH MODEL UNCERTAINTY AND
TEMPERATURES CLOSE TO AN HPC MEX BLEND.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL THROUGHOUT THE TAF PERIOD AS HIGH
PRESSURE BUILDS IN FROM THE SOUTH TODAY. MID-LEVEL CLOUDS WILL
CROSS THE AREA THIS AFTERNOON.
SOUTHWESTERLY WINDS CAN GUST TO 20KTS AT KFKL/KDUJ. WINDS WILL
DIMINISH TONIGHT AS MID-LEVEL CLOUDS CONTINUE TO FILTER ACROSS THE
TERMINALS. AM CONSIDERING MENTION OF LOW LEVEL WIND SHEAR TONIGHT,
AS NAM MODEL PROFILES SHOW A STABLE SURFACE LAYER TONIGHT WITH
WINDS INCREASING TO OVER 40 KTS ABOVE 2 KFT AGL.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
VFR CONDITIONS WILL CONTINUE TUESDAY EVENING. A COLD FRONTAL BAND
OF SHOWERS WILL PROVIDE RESTRICTIONS LATE TUESDAY NIGHT INTO
WEDNESDAY MORNING. POST FRONTAL STRATOCUMULUS MAY CAUSE CEILING
RESTRICTIONS TO LINGER INTO THURSDAY. VFR CONDITIONS WILL RETURN
TO THE TERMINALS ON FRIDAY AS HIGH PRESSURE BUILDS INTO THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1202 AM EST MON JAN 30 2012
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.UPDATE /ISSUED AT 805 PM/...
TEMPS HAVE FALLEN QUITE SHARPLY NEAR THE WI BORDER WHERE SKIES HAVE
CLEARED IN THE PRESENCE OF LGT WINDS AND DRY AIRMASS...PROBABLY WELL
REPRESENTED BY 12Z PWAT OF 0.09 INCH AT INL. SO LOWERED GOING FCST
MIN TEMPS IN AREAS WHERE SKIES ARE NOW CLR NEAR THE WI BORDER OR WL
BECOME MOCLR OVERNGT INLAND FM LK SUP. WITH THE ARRIVAL OF WAD CLD
LATER TNGT...EXPECT TEMPS TO RISE THEN...SO ADJUSTED HOURLY TEMPS IN
THE GRIDS TO REFLECT THESE EXPECTATIONS.
EARLIER UPDATE ISSUED AT 7 PM...
OPTED TO ISSUE AN LES ADVY FOR ERN ALGER/NRN LUCE COUNTY UNTIL EARLY
MON MRNG AS 18Z NAM/LOCAL WRF-ARW RUNS SHOW AREA OF FOCUSED LLVL
CNVGC IN THIS AREA THRU ABOUT 06Z WITH MORE WSW LAND BREEZE FLOW
OVER THE INTERIOR AND PERSISTENT WNW FLOW OVER THE WATER. WFR-ARW
RUN ALSO INDICATES FAVORABLE OMEGA WITHIN THE DGZ IN THIS AREA WITH
INVRN BASE ARND 5K FT...SO HEADLINE SEEMS WARRANTED. ONCE THE H925
WINDS BACK SUFFICIENTLY TO WSW BY ARND 09Z...LINGERING LES SHOULD
SHIFT OFFSHORE.
COORDINATED WITH APX.
&&
.SHORT TERM /TONIGHT AND MONDAY/ ISSUED AT 449 PM...
WV IMAGERY AND RUC ANALYSIS SHOWS THE UPPER TROUGH THAT HAS BEEN
OVER THE UPPER GREAT LAKES OVER THE LAST DAY STARTING TO SHIFT TO
THE EAST. UPSTREAM...BROAD MOISTURE PLUME RUNNING OVER THE RIDGE
OVER THE US/CANADIAN ROCKIES AND MOVING INTO THE NRN PLAINS. CLOSER
TO HOME...VIS SATELLITE SHOWING LAKE EFFECT CLOUDS HANGING ON OVER
MUCH OF UPPER MICHIGAN...BUT DRIER AIR FROM THE APPROACHING SFC
RIDGE IN MN HAS QUICKLY ATE AWAY AT THE CLOUDS/SHOWERS OVER WRN LK
SUPERIOR. OVER THE ERN LK...LES CONTINUES...ALTHOUGH THE DRIER AIR
HAS STARTED TO DIMINISH THE INTENSITY OF THE SHOWERS...WHICH KMQT
RADAR IS SHOWING MAINLY 1HR SNOWFALL RATES OF 0.5 IN/HR. THE
STRONGEST SWRN BAND NEAR MUNISING HAS PICKED UP SLIGHTLY OVER THE
LAST HOUR...AS LLVL WINDS OFF MARQUETTE COUNTY HAVE SHIFTED SLIGHTLY
TO THE WNW AND INCREASED CONVERGENCE.
TONIGHT...WITH THE UPPER TROUGH CONTINUING TO PUSH E...SFC RIDGE
CURRENTLY OVER THE MN WILL PUSH INTO THE AREA. H850-700 SUBSIDENCE
AND DRY AIR ALREADY TAKEN HOLD OVER WRN LK SUPERIOR AND DIMINISHED
THE -SHSN OVER THE WRN CWA. AS SFC HIGH BUILDS INTO UPPER MI THIS
EVENING...WINDS WILL BE BACKING THROUGH THE EVENING HOURS AND END UP
FOCUSING ANY LINGERING LES OVER THE KEWEENAW PENINSULA BY MIDNIGHT.
SINCE INVERSION HEIGHTS ON BUFKIT SOUNDINGS OVER THE KEWEENAW ARE
ONLY AROUND 3KFT...DON/T EXPECT MUCH FOR ACCUMULATIONS...ESPECIALLY
WITH THE TRANSIENT NATURE OF THE LES.
OVER ERN ALGER AND LUCE COUNTIES...EXPECT LES TO BE ONGOING AT THE
START OF THE TONIGHT PERIOD WITH THE NW FLOW AND -18C H850 TEMPS.
DEEPER MOISTURE WILL DEPART LATE THIS AFTN AS SUBSIDENCE FROM
H850-700 WITH THE UPPER RIDGING WILL CAUSE INVERSION HEIGHTS TO FALL
TO 4-5KFT. STILL SHOULD SEE LES CONTINUING IN THE NW WIND SNOW BELTS
FROM MUNISING E THIS EVENING...BUT INTENSITY WILL BE LOWER THAN
TODAY. IN ADDITION...WITH WINDS BACKING TO THE W BY MIDNIGHT AND
THEN SW BY DAYBREAK...THE BANDS SHOULD BE SHIFTING TO THE ENE FROM
LATE EVENING ON. THUS...EXPECT LIMITED ACCUMULATION DUE TO THE
TRANSIENT NATURE OF THE BANDS AND WILL LET THE WARNING CONTINUE
UNTIL 00Z.
LOWS TONIGHT ARE VERY TRICKY...SINCE CLEARING SKIES...WEAKENING
WINDS WITH THE SFC RIDGE...AND PWATS AROUND 35 PERCENT OF NORMAL
LEAD TO A FAVORABLE RADIATION COOLING NIGHT. FORECAST IS DIFFICULT
DUE TO THE APPROACHING HIGH CLOUDS CURRENTLY MOVING INTO WRN MN.
THESE SHOULD START TO ARRIVE AFTER MIDNIGHT AND CAUSE FOR STEADY OR
RISING TEMPS LATE. WENT WITH A NON-DIURNAL TREND AND HAVE LOWS ALONG
THE WI BORDER IN THE MID SINGLE DIGITS BELOW ZERO AND WOULD NOT BE
SURPRISED IF THEY GET EVEN COLDER IF CLOUDS ARE DELAYED.
LATE TONIGHT INTO MONDAY...CLIPPER SYSTEM CURRENTLY TAKING SHAPE IN
ALBERTA WILL SLIDE A WARM FRONT ACROSS MN AND WI ON MON. H700-500
WAA AND MOISTURE...ALONG WITH ISENTROPIC ASCENT ON THE 275-300K SFCS
PUSHES ACROSS THE AREA FROM SW TO NE BETWEEN 09Z AND 18Z MON. BEST
MID LVL WAA LOOKS TO FOCUS OVER THE S HALF OF UPPER MI...MAINLY OVER
THE SCNTRL AND ALONG THE LK MI SHORELINE. WILL FOLLOW THAT SOLN FOR
QPF AMNTS FOR LATE TONIGHT INTO MON MORNING. WITH A GOOD CONSENSUS
ON FORCING/QPF/TIMING...HAVE BUMPED POPS UP TO LIKELY FOR MOST OF
THE LAND AREAS.
12Z NAM/GFS/GEM-REG CONSISTENT ON 0.12-0.2IN OF QPF OVER THE SRN
HALF OF UPPER MI BY MON EVENING AND MADE SOME MINOR ADJUSTMENTS UP
FROM PREVIOUS SHIFT. COBB OUTPUT FOR KESC/KIMT SHOWING HIGH RATIOS
AROUND 15/18-1 INITIALLY...THEN FALLING BELOW 10-1 HEADING INTO THE
AFTN AS THE DEEPER MOISTURE IS CUT OUT REMAINING FORCING/MOISTURE IS
BELOW THE DGZ. THINK MUCH OF THE SNOW WILL FALL IN THE HIGHER SNOW
RATIO PERIOD AND USED THAT AS THE STARTING POINT FOR SNOWFALL.
EXPECT A PERIOD OF LK ENHANCEMENT AFTER 15Z ON MON...WHEN LLVL
MOISTURE PROFILES FINALLY MOISTEN UP AND SRLY WINDS TAKE HOLD. WITH
H850 TEMPS AROUND -11C DURING THE PCPN PERIOD...SHOULD BE ENOUGH
LLVL INSTABILITY TO PROVIDE ENHANCEMENT OVER DELTA/SCHOOLCRAFT/LUCE
COUNTIES AND HAVE BUMPED UP QPF AMNTS SLIGHTLY IN THOSE
AREAS...ESPECIALLY SCHOOLCRAFT/LUCE. OVERALL...HAVE A GENERAL 1-2IN
OVER MUCH OF THE CWA. COULD BE SOME ISOLATED ADVY AMNTS OF 3IN OVER
THE SCNTRL AND ALONG THE LK MI SHORELINE...BUT THE OVERALL AVG WILL
BE BELOW ADVY AND WILL NOT ISSUE ANYTHING AT THIS TIME.
FINALLY...WITH THE MAIN FORCING AND DEEPER MOISTURE PULLING NE IN
THE AFTN...COULD SEE A PERIOD OF FZDZ. THIS IS DUE TO THE LINGERING
FORCING/MOISTURE BELOW THE ICE CRYSTAL AREA /ISENTROPIC ASCENT ON
275-280K SFCS AND H925-800 MOISTURE/. ADDED THIS TO THE GRIDS IN THE
AFTN FROM SW TO NE AS THE DEEP MOISTURE PULLS OUT...AND MAY BE MOST
PRONOUNCED OVER THE HIGHER TERRAIN NCNTRL...WHERE THE SSE UPSLOPE
FLOW WOULD FAVOR IT.
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
BIG FCST QUESTION FOR MONDAY NIGHT INTO TUESDAY TIME FRAME WILL BE
THE POTENTIAL FOR FZDZ IN THE WAKE OF MONDAYS TROUGH/WARM FRONT.
FCST SNDGS...ESPECIALLY THE NAM BUFR SNDGS...SHOW LINGERING SHALLOW
MOIST LAYER NEAR THE SFC AS DRYING/SUBSIDENCE OCCURS IN MID-LVLS IN
THE WAKE OF THE WARM FRONT. EXPECT LOCATIONS AFFECTED BY AN UPSLOPE
SRLY FLOW WILL BE MOST SUSCEPTIBLE TO PATCHY FZDZ MON NIGHT INTO
TUESDAY MORNING BUT WILL INCLUDE A MENTION FOR MOST OF THE CWA. ANY
LINGERING FZDZ SHOULD TURN TO DZ TUE AFTERNOON AS MOIST LOW-LVLS
WARM ABV FREEZING.
ANOTHER SHORTWAVE AND ASSOC COLD FRONT WILL MOVE THROUGH TUE
AFTERNOON AND TUE NIGHT. TRACK OF THE SHORTWAVE AND THE ASSOC SFC
LOW WOULD FAVOR MAINLY THE NRN TIER FOR SOME LIGHT RAIN OR SNOW AS
THIS IS WHERE MODELS INDICATE DEEPER MOISTURE AND CLOSER PROXIMITY
TO MODERATE Q-VECT CONV AND LIFT ASSOC WITH SHORTWAVE. RAIN/SNOW MIX
ALONG THE NRN TIER SHOULD TURN OVER TO ALL SNOW LATE TUE NIGHT WITH
CAA BEHIND FRONT AND WOULD EXPECT A DIMINISH TREND AS SHORTWAVE/SFC
LOW DEPART QUICKLY EAST.
WEAK RDGG BUILDING IN FROM THE WEST SHOULD RESULT IN MAINLY DRY
CONDITIONS ON WEDNESDAY.
FOR THE EXTENDED /THURSDAY THROUGH SUNDAY/...
MODEL DISAGREEMENTS WILL CONTINUE THROUGHOUT THE REMAINDER OF THE
FORECAST PERIOD PERTAINING TO THE LOCATION AND TIMING OF SHORTWAVES
AFFECTING THE AREA...SO HAVE NOT DIVERGED MUCH FROM CONSENSUS THIS
FAR OUT. MODELS ARE IN FAIRLY GOOD AGREEMENT...HOWEVER...THAT STRONG
RIDGING OFF THE PACIFIC NORTHWEST WEDNESDAY NIGHT/THURSDAY MORNING
WILL ALLOW THE JET STREAM TO TRANSITION TO A MERIDIONAL FLOW ON THE
DESCENDING BRANCH...CREATING AN ENHANCED TROUGHING PATTERN OVER THE
CENTRAL CONUS. GFS IS THE MOST PROGRESSIVE OF THE MODELS...KEEPING
THE TROUGH PLACEMENT FARTHER NORTH AND HAVING IT MOVE EAST MORE
QUICKLY THAN ECMWF/GEM. AS HIGH PRESSURE CONTINUES TO BUILD IN WEST
THROUGH SUNDAY...DESCENDING BRANCH OF TROUGH WILL BEGIN TO
RETROGRADE AND BECOME POSITIVELY TILTED.
TRANSLATING THIS TO THE UPPER GREAT LAKES REGION...OVERALL...THIS
WILL CREATE A FAIRLY BENIGN SYNOPTIC WEATHER PATTERN AS MUCH OF THE
SHORTWAVES WILL PASS TO OUR SOUTH TRAVERSING THE DESCENDING EDGE OF
THE TROUGH. HOWEVER...IF THE MORE NORTHERN PLACEMENT OF THE GFS PANS
OUT...AS THE TROUGH BECOMES POSITIVELY TILTED OVER THE UPPER GREAT
LAKES ON FRIDAY...EXPECT SHORTWAVE TO DEVELOP AND TRAVERSE THE AREA.
THIS WILL BRING THE BEST CHANCE FOR PRECIP DURING THE PERIOD
WITH STRONG QVECTOR CONVERGENCE AND FAIRLY MOIST PROFILE/STEEP LAPSE
RATES DURING ITS PASSAGE. THE ECMWF AND THE GEM ON THE OTHER HAND
HAVE THIS SYSTEM DEVELOPING MUCH FARTHER SOUTH AND THEREBY NOT
IMPACTING THE FORECAST PERIOD AT ALL...SO DIDN`T GO ANY HIGHER THAN
SLIGHT CHANCES. OTHERWISE...PREDOMINATE W AND SW WINDS ALOFT AHEAD
OF DESCENDING JET WILL KEEP TEMPERATURES WELL ABOVE NORMAL THURSDAY.
WITH LOW CONFIDENCE ON PLACEMENT AND STRENGTH OF JET AS IT NEARS THE
AREA...WILL KEEP WITH THE LOWERING TREND OF TEMPS AS WINDS TURN MORE
NORTHERLY BY THE END OF THE PERIOD...BUT MAGNITUDE OF THIS COLD AIR
INTRUSION IS YET TO BE DETERMINED. IF THE MORE AMPLIFIED TROF AND
COLDER SOLN OF THE ECMWF SOLUTION VERIFIES...THEN TEMPS WILL
PROBABLY NEED TO BE LOWERED AND POPS MAY NEED TO BE INCREASED FOR
NEXT WEEKEND FOR AREAS DOWNWIND OF LAKE SUPERIOR IN N-NW FLOW.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
AS A HI PRES RDG MOVES E ACROSS THE UPR MIDWEST EARLY THIS MRNG AND
THE FLOW BACKS MORE TO THE SW...EXPECT LINGERING LO CLDS/MVFR CIGS
AT CMX/SAW TO GIVE WAY TO CLRG AND VFR CONDITIONS. ALTHOUGH MID/HI
CLDS WL THICKEN TOWARD SUNRISE...EXPECT VFR CONDITIONS WITH LLVL DRY
AIR AT IWD. AS A WARM FNT TO THE W MOVES CLOSER THIS MRNG...EXPECT
PERIODS OF -SN TO DVLP WITH CONDITIONS DETERIORATING TO MVFR...
FIRST AT IWD AND THEN AT SAW/CMX BY LATE MRNG. SINCE THE S WIND WL
DOWNSLOPE AT IWD AND CMX...CONDITIONS AT THOSE SITES WL PROBABLY
HAVE A HARDER TIME FALLING TO IFR THAN AT SAW. EVEN AFT THE SN
ENDS...LO CLDS AND MVFR/IFR CIGS WL LINGER WITH FORECAST SOUNDINGS
SHOWING CONSIDERABLE LLVL MSTR.
&&
.MARINE /FOR THE 4PM LAKE SUPERIOR FORECAST ISSUANCE/...
HIGH PRESSURE RIDGE SHIFTING OVER LAKE SUPERIOR TONIGHT WILL BRING
DECREASING WINDS TONIGHT...BELOW 20KTS. A CLIPPER SYSTEM DEVELOPING
IN ALBERTA WILL BEGIN TO MOVE INTO THE NORTHERN PLAINS ON MONDAY
AFTERNOON AND EVENING BEFORE MOVING ACROSS THE UPPER GREAT LAKES ON
TUESDAY NIGHT. SOUTHERLY WINDS AHEAD OF THIS SYSTEM COULD PRODUCE
GUSTS TO 30KTS OVER THE ERN LK ON MONDAY AFTN AND EVENING. THE LOW
WILL SHIFT E ON WED...ALLOWING WEAK HIGH PRESSURE TO BUILD OVER THE
UPPER GREAT LAKES THROUGH THURS. A LOW PRESSURE SYSTEM WILL MOVE
THROUGH THE OHIO RIVER VALLEY ON FRI...BUT SHOULD HAVE LIMITED
EFFECTS ON LK SUPERIOR. EXPECT WINDS TO BE BELOW 25KTS FROM TUESDAY
MORNING THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST MONDAY FOR MIZ006-007.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...VOSS
EXTENDED...JMW
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1100 PM CST SUN JAN 29 2012
.UPDATE...
UPDATED TO INCLUDE 06Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
ANOTHER MILD WEEK IS AHEAD OF US...WITH HIGHS IN THE MID 30S TO
LOWER 40S COMING FOR MONDAY THROUGH THURSDAY. IMPRESSIVE WARM
FRONT COMING THROUGH TONIGHT WILL BRING ABOUT THE CHANCE FOR
ANOTHER DUSTING OF SNOW...WHILE A LOW PASSING ACROSS NRN MN
TUESDAY MAY BRING SOME LIGHT PRECIP TO NRN SECTIONS OF THE CWA.
AFTER THAT...THE REST OF THE FORECAST IS DRY...WITH ONLY A MODEST
COOL DOWN EXPECTED FOR THE WEEKEND.
STRONG WARM FRONT THIS AFTERNOON STRETCHES FROM KC TO NE MONTANA.
TO GO ALONG WITH THIS...UPPER RIDGE IS WORKING INTO THE
PLAINS...WITH THE RUC SWINGING 160M 12 HR H5 HEIGHT RISES ACROSS
THE AREA THIS AFTERNOON. COMBINATION OF A SHORTWAVE MOVING INTO
MT...ALONG WITH STRONG ISENTROPIC/FGEN FORCING TO THE NORTH OF THE
FRONT HAS RESULTED IN THE GENERATION OF A NICE BAND OF SNOW ACROSS
NODAK. SHORT TERM HI RES GUIDANCE ALL SIMILAR WITH THIS BAND OF
SNOW REACHING THE NW CWA BETWEEN 2Z AND 4Z AND QUICKLY WORKING
EAST THROUGH THE NIGHT...EXITING THE WI CWA AROUND 15Z MON
MORNING. ONE ISSUE TO WATCH FOR TONIGHT IS A DRY LAYER OF AIR THAT
IS DEVELOPING THIS AFTERNOON BETWEEN H9 AND H7. INDICATIONS FROM
BUFKIT SOUNDINGS IS THAT WE WILL BE MOISTENING THIS LAYER FROM
TOP-DOWN...SO MUCH OF THE SNOW MAY BE LOST TO SUBLIMATION. ARW
1 KM AGL REFLECTIVITY FORECASTS ARE SPOTTY/NON-EXISTENT ACROSS
MUCH OF THE MPX CWA...AND THIS DRY LAYER LIKELY HAS A LOT TO DO
WITH IT. STILL...SREF PROBS ARE UP OVER 80 PERCENT FROM CENTRAL MN
INTO WRN WI...WHICH MATCHES UP WELL WITH BEST THALER QG FORCING.
THEREFORE...HAVE CATEGORICAL POPS ALONG AND NORTH OF AN
AXN/STC/EAU LINE FOR TONIGHT...WHERE FORCING AND MOISTURE LOOK
MOST LIKELY TO COINCIDE. CERTAINLY LOOKING GRIM FOR ANYONE ALONG
AND SOUTH OF THE MN RIVER TO SEE MUCH PRECIP. AS FOR
P-TYPE...STILL SEEING A SIGNIFICANT WARM NOSE COMING IN WITH THE
WARM FRONT...BUT MODELS CONTINUE TO SHOW THE PRECIP REMAINING OUT
AHEAD OF THE WARM NOSE...WITH ONLY AN HOUR OR TWO OF A WINTRY MIX
POSSIBLE AS THE PRECIP PULLS OUT. LOOKS TO BE YET ANOTHER SYSTEM
THIS YEAR THAT LAYS DOWN A QUICK HALF INCH TO AN INCH WHERE
CATEGORICAL POPS ARE LOCATED.
BESIDE THE PRECIP COMING IN...ALL GUIDANCE SIMILAR WITH A NON-
DIURNAL TREND FOR TONIGHT...WITH HIGHS STEADILY RISING THROUGH THE
NIGHT. IN FACT...GFSLAMP HAS ABOUT 10 DEGREES OF WARMING FOR ALL
MN LOCATIONS THROUGH THE NIGHT. EVEN IN WI...TEMPS SHOULD ONLY
FALL THROUGH ABOUT 3Z BEFORE GOING STEADY AND THEN RISING.
BIG QUESTION FOR MONDAY IS WHERE DOES THE WARM FRONT SET UP. 12Z
GUIDANCE HAS THE FRONT SOMEWHERE BETWEEN I-94 AND A HINCKLEY TO
FARGO LINE AT 6PM MONDAY. THIS WILL LEAD TO SOME UNCERTAINTY FOR
HIGHS ON MONDAY...AS AREAS SOUTH OF THE WARM FRONT WILL LIKELY
MAKE A RUN INTO THE 40S...WHILE AREAS ALONG AND NORTH REMAIN
CLOUDY WITH HIGHS LIKELY ONLY TOPPING OUT AROUND FREEZING. IN
ADDITION...THERE IS SOME CONCERN FOR DRIZZLE NORTH OF THE FRONT
GIVEN THE AMOUNT OF LOW LEVEL MOISTURE EXPECTED. HOWEVER...NAM/GFS
BUFKIT SOUNDINGS OVER CENTRAL MN SHOW A SHALLOW MIXED BOUNDARY
LAYER DEVELOPING DURING THE AFTERNOON...WITH A BIT OF A TEMP/DEWP
SPREAD NOTED ON THE SOUNDINGS. BECAUSE OF THIS...NOT TOO CONFIDENT
THAT WE WILL SEE THAT MUCH DZ GENERATION ACROSS CENTRAL
MN...DESPITE PERSISTENT LIFT ALONG THE FRONT. OTHER VARIABLE TO
CONTEND WITH FOR TEMPS ON MONDAY WILL BE SNOW COVER. SATELLITE
IMAGES THIS MORNING SHOWED MOST OF YELLOW MEDICINE AND LAC QUI
PARLE COUNTIES ARE SNOW FREE...AND GIVEN FAVORABLE WSW FLOW ON
MONDAY...PLACES SUCH AS MADISON AND MONTEVIDEO COULD SEE HIGHS TOP
OUT IN THE LOW 50S. SOUTH CENTRAL MN HAS THE OPPOSITE PROBLEM...AS
COOP OBSERVES THIS MORNING REPORTED 3 TO 5 INCHES OF SNOW ON THE
GROUND DOWN THERE...THIS MAY RESULT IN HIGHS BEING A BIT OVER DONE
DOWN THERE. AT ANY RATE...A BLEND OF THE MET/MAV BIAS CORRECTED
DATA WAS USED FOR HIGHS TOMORROW.
THE MILD CONDITIONS WILL REMAIN IN PLACE MONDAY NIGHT THROUGH
THURSDAY. MODELS SWING A COLD FRONT ACROSS THE AREA TUESDAY
MORNING...WITH LOWS IN THE WARM SECTOR OUT AHEAD OF IT MONDAY
NIGHT LIKELY STRUGGLING TO FALL BELOW FREEZING. H85 TEMPS LOOKS TO
ONLY GET KNOCKED DOWN TO AROUND 0C BEHIND THE FRONT...WITH HIGHS
TUESDAY THROUGH THURSDAY LOOKING TO BE A DEGREE OR TWO COLDER THAN
THE PREVIOUS DAY. IN FACT...OVERNIGHT LOWS LOOK TO ONLY FALL BACK
TO AROUND THE AVERAGE HIGHS FOR THIS TIME OF YEAR. BY THE TIME
JANUARY IS ALL SAID AND DONE...SHOULD HAVE AN AVERAGE TEMPERATURE
DEPARTURE AT MSP SOMEWHERE IN THE NEIGHBORHOOD OF 8 DEGREES...WITH
JANUARY OF 2012 POSSIBLY REPLACING JANUARY OF 1933 AS 8TH WARMEST
ALL TIME /23.1 WAS THE AVE TEMP FOR JAN OF 1933/.
ONLY OTHER CHANCE FOR PRECIP LOOKS TO COME LATE MONDAY NIGHT INTO
TUESDAY AS A SFC LOW TRACKS ACROSS NRN MN. UNFORTUNATELY...THIS
LOW AND ITS ASSOCIATED COLD FRONT WILL BE ENCOUNTERING QUITE A BIT
OF DRY AIR OVER THE MPX CWA...WITH BEST PRECIP SIGNAL BEING UP
ACROSS NRN MN. STILL...SLIGHT SOUTHWARD SHIFT IN MODELS THIS
MORNING PROMPTED AN INTRODUCTION FOR SOME SLIGHT CHANCE POPS
ACROSS FAR NRN CWA LATE MONDAY NIGHT THAT LAST THROUGH THE DAY ON
TUESDAY. AN PRECIP AMOUNTS LOOK LIGHT...WITH P-TYPE BEING A RA/SN
MIX INTO TUESDAY MORNING THAT TRANSITIONS TO MAINLY RA DURING THE
DAY.
AS WE END THE WEEK...THE BIG STORY HERE WILL BE THE SIGNIFICANT
PATTERN SHIFT THE MEDIUM RANGE MODELS ARE SHOWING GOING INTO THE
WEEKEND. OUR CURRENT FAST WNW FLOW LOOKS TO BECOME MORE AMPLIFIED
BY THE WEEKEND...WITH A STRONG UPPER RIDGE DEVELOPING OVER WRN
NOAM AND THE PATTERN RESEMBLING MORE A LA NINA SITUATION FOR
ONCE. THOUGH THIS DOES OPEN US UP TO N/NW FLOW THIS WEEKEND...THE
ASSOCIATED COOL DOWN LOOKS TO ONLY TAKE ABOUT 10 DEGREES OFF OF
HIGHS...WITH READINGS GOING FROM 15 TO 20 DEGREES ABOVE NORMAL BACK
DOWN TO 5 TO 10 DEGREES ABOVE NORMAL. THERE ARE NO INDICATIONS OF
SIGNIFICANT COLD AIR SHOWING UP UNTIL THE SECOND WEEK OF
FEB...WHEN BOTH THE GFS/ECMWF SHOW A POLAR VORTEX SHOWING UP OVER
SRN HUDSON BAY. EVEN THEN THOUGH...MN LOOKS TO BE ON THE BOUNDARY
BETWEEN THE ARCTIC AIR TO THE EAST AND THE MILD PACIFIC AIR TO THE
WEST.
&&
.AVIATION.../06Z TAF ISSUANCE/
WARM FRONT BUILDING INTO SOUTHWEST MN THIS EVENING AND GRADUALLY
SATURATING ATMOSPHERIC COLUMN ACROSS EASTERN AREAS. RADAR TRENDS
INDICATE INCREASING REFLECTIVITY PATTERN TO THE WEST OF KSTC/KMSP.
SHOULD SEE SOME LIGHT SNOW MOVE EAST INTO WEST CENTRAL WISCONSIN THE
REMAINDER OF THE NIGHT. AS PRECIPITATION ENDS AND WARM FRONT SURGES
TO THE NORTHEAST...SHOULD SEE LOWERING CEILINGS TO IFR FROM EAST OF
KMSP INTO WISCONSIN AFTER THROUGH MONDAY MORNING. EXPECT THIS TO
LIFT NORTHEAST DURING THE REMAINDER OF THE DAY WITH STRATUS LIFTING
TO THE NORTH OF THE TAF SITES BY 18Z. THEN VFR CONDITIONS INTO
MONDAY NIGHT. SOUTHEAST SURFACE WIND FLOW AHEAD OF FRONT...MAY BE A
BIT GUSTY AT KAXN INTO THE EARLY MORNING BEFORE FROPA. THEN WINDS
BECOMING MORE SOUTH TO SOUTHWEST DURING TH DAY MONDAY AS WARM AIR
LIFTS TO THE NORTHEAST.
KMSP...LOWERING CEILINGS TO MVFR WITH SOME LIGHT SNOW FROM 07Z-09Z.
QUESTION REMAINS IF WE SATURATE AHEAD OF INCOMING WARM FRONT. WILL
HOLD ONTO MVFR CEILINGS THROUGH 14Z THEN BECOMING VFR WITH FROPA.
SOME THREAT OF IFR STRATUS CEILINGS BEFORE FROPA IN THE MORNING AND
WILL HAVE TO MONITOR. SOUTHEAST WINDS BECOMING MORE SOUTH TO
SOUTHWEST DURING THE DAY MONDAY AS WARMER AIR MOVES INTO THE
REGION.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
601 PM CST TUE JAN 31 2012
.DISCUSSION...
/245 PM CST TUE JAN 31 2012/
UNSEASONABLY WARM CONDITIONS BLANKET THE AREA AGAIN THIS AFTERNOON
WITHIN THE WARM SECTOR AHEAD OF THE APPROACHING COLD FRONT. LOW
LEVEL MOISTURE CONTINUES TO SLOWLY INCREASE ACROSS THE REGION AND
POCKETS OF WEAK CAPE ARE EVIDENT ON THE LATEST SPC MESOANALYSIS.
THE COLD FRONT WILL PROGRESS ACROSS THE AREA TONIGHT AS THE
ATTENDANT SHORT WAVE TROF MIGRATES EASTWARD. IT STILL LOOKS AS
THOUGH THE COMBINATION OF WEAK ASCENT ASSOCIATED WITH THE UPPER
TROF AND LOW LEVEL WAA WILL BE ENOUGH TO HELP GENERATE SOME
ISOLATED TO SCATTERED SHOWERS AND PERHAPS EVEN A THUNDERSTORM. THE
HIGHEST PROBABILITIES WILL BE ACROSS SE MO AND SW IL.
THIS FRONT SHOULD BE LOCATED ACROSS FAR SE MO AND SRN IL AT DAYBREAK
ON WEDNESDAY. THE FRONT WILL CONTINUE TO SETTLE SOUTH INTO THE
LOWER MS VALLEY DURING THE DAY AS WEAK HIGH PRESSURE BUILDS INTO
THE AREA. COOLING IN THE WAKE OF THE FRONT IS NOT DRAMATIC AND
HIGHS ARE STILL EXPECTED A GOOD BIT ABOVE AVERAGE FOR THE FIRST
DAY OF FEBRUARY. I HAVE NUDGED TEMPS UP SOME FROM THE PREVIOUS
FORECAST...SEEMS LIKE YOU CAN`T GO WARM ENOUGH THESE DAYS.
THE WEAK BUT BROAD HIGH PRESSURE SYSTEM WILL CONTINUE TO DOMINATE
THE AREA WEDNESDAY NIGHT INTO THURSDAY BUT WILL BE SLOWLY
RETREATING TO OUR EAST. STILL TEMPERATURES WILL BE ABOVE AVERAGE.
ATTENTION THE LATER PART OF THE WEEK AND INTO THE WEEKEND TURNS TO
THE PROBLEMATIC STORM SYSTEM WE HAVE BEEN EYEING FOR THE LAST 3
DAYS OR SO. THE MODELS ARE REASONABLY CLOSE THROUGH LATE FRIDAY
SHOWING LARGE SCALE AMPLIFICATION TO THE UPPER AIR PATTERN AS A
DEEP TROF AND CLOSED DEVELOP THROUGH THE ROCKIES AND INTO THE
PLAINS. BY LATE SATURDAY AND INTO SUNDAY HOWEVER THERE IS
CONSIDERABLE MODEL SPREAD IN THE POSITION OF THE EASTWARD MOVING
UPPER LOW...IE OVER 500 MILES...WITH THE GFS AND GFS ENSEMBLE MEAN
MORE PROGRESSIVE. CHANGES ARE STILL ANTICIPATED IN THE MODEL
SOLUTIONS OVER THE ENSUING DAYS. AT THIS TIME THERE IS RELATIVELY
HIGH CONFIDENCE THAT A STORM SYSTEM WILL IMPACT THE REGION FRIDAY
INTO SATURDAY NIGHT. BARING ANY BIG MODEL SHIFTS...THE
PRECIPITATION THROUGH SATURDAY SHOULD BE ALL RAIN WITH EVEN
THUNDER POSSIBLE AS A STOUT SOUTHERLY LLJ TRANSPORTS WARM MOIST
AIR INTO THE AREA. STILL WATCHING SOME TIMING ISSUES WITH THE
ONSET OF RAIN ON FRIDAY WITH THE ECMWF AND CMC GEM A BIT SLOWER
THAN THE GFS AND NAM. MORE UNCERTAINTY COMES INTO PLAY SATURDAY
NIGHT INTO SUNDAY WITH THE FASTER GFS/GFS ENSEMBLE SOLUTIONS
BRINGING DEEPENING COLD AIR INTO THE AREA AND SUGGESTING SOME
SNOW POTENTIAL. AT THIS POINT WE WILL CONTINUE TO MENTION THE
POSSIBILITY OF RAIN OR SNOW...WITH LOW CONFIDENCE IN THE LATER.
GLASS
&&
.AVIATION...
/555 PM CST TUE JAN 31 2012/
VFR SC DECK BLANKETS MOST OF THE AREA EARLY THIS EVENING. W EDGE
OF THE MOST EXTENSIVE CLOUD COVER IS APPROACHING A COU-UIN LINE
ATTM...WITH A MORE CONVECTIVE LOOKING SCT-BKN CLOUD FIELD BEWTEEN
THIS BACK EDGE AND COLD FRONT...WHICH IS NEAR AN IRK-PPK LINE.
IN GENERAL CLOUDS AOB 6KFT SHOULD CONTINUE TO CLEAR FROM W-E
DURING THE EVENING...BUT EXPECTING SOME MINOR LOWERING OF CIGS
OVER STL AREA EARLY THIS EVENING WITH THE PERSISTENT MOIST S FLOW
AND SUBTLE COOLING OF THE BOUNDARY LAYER...ALONG WITH SOME VERY
SPOTTY -SHRA. DRIER AIR WITH PASSAGE OF COLD FRONT SHOULD CLEAR
CLOUDS OUT OF STL AREA NO LATER THAN MIDNIGHT...WITH THE POSSIBILITY
OF SOME LIGHT MVFR FOG IN THE AREA DURING THE PREDAWN HOURS.
SPECIFICS FOR KSTL...AS MENTIONED ABOVE...EXPECT A SUBTLE LOWERING
OF CIGS IN THE STL AREA OVER THE NEXT FEW HOURS...ALONG WITH MORE
MISS THAN HIT --SHRA. OVER THE PAST 2 HOURS THERE HAS BEEN SOME
VERY SPOTTY REPORTS OF HIGH END MVFR CIGS OVER S CENTRAL/SE MO
(2500-3000 KFT)...SO FOR NOW HAVE LOWERED CIGS TO AROUND 3KFT.
LATEST RUC DATA...AS WELL AS EXTRAPOLATION OF CLOUD TRENDS FROM
SATELLITE...SUGGEST THAT THIS CLOUD DECK SHOULD BREAK 04-06Z AS
FROPA BEGINS TO SCOUR OUT MOST OF THE LOW LEVEL MOISTURE. I ALSO
LEFT MENTION OF FOG IN THIS ISSUANCE. DEWPOINTS DO DROP OFF FAIRLY
RAPIDLY BEHIND THE FRONT...SO WINDOW FOR FOG FORMATION IS GOING TO
BE SMALL. IF SWD PUSH OF FRONT IS A BIT MORE AGGRESSIVE...AS IS
SUGGESTED BY SOME OF THE OFF-CYCLE MODEL RUNS...THIS THREAT WILL
BE S OF STL. WILL MONITOR 00Z GUIDANCE FOR ADJUSTMENTS TO THIS FOG THREAT.
TRUETT
&&
.CLIMATE...
RECORD HIGHS FOR TUESDAY JANUARY 31ST
KSTL 74 IN 1989
KCOU 74 IN 1989
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1209 PM CST MON JAN 30 2012
.DISCUSSION...
/323 AM CST MON JAN 30 2012/
MAIN CONCERNS ARE WELL ABOVE NORMAL TEMPERATURES THE NEXT TWO DAYS AND
THEN CHANCES FOR SNOW LATE THIS WEEK INTO NEXT WEEKEND.
STILL BELIEVE WE WILL BE IN RECORD TEMPERATURE TERRITORY TODAY GIVEN
THE MOSTLY SUNNY SKIES AND SOUTHWEST WINDS WHICH ARE TYPICALLY A
WARM UP WIND. RUC SOUNDINGS DO SHOW AN INVERSION AROUND 900MB
WHICH WILL LIMIT MIXING HEIGHTS TODAY...HOWEVER THE TEMPERATURES
AT THIS LEVEL WILL BE AROUND +10C WHICH STILL FAVORS HIGHS
REACHING THE LOWER TO MIDDLE 60S OVER MUCH OF THE AREA. THESE
VALUES MATCH THE MOS TEMPS REASONABLY WELL. SURFACE PRESSURE
GRADIENT WILL REMAIN TIGHT ENOUGH TONIGHT TO PREVENT MUCH OF A DROP
OFF IN WIND SPEED...AND HENCE SHOULD KEEP LOWS FROM FALLING MUCH
BELOW NORMAL DAYTIME HIGHS FOR THE END OF JANUARY. THE WARM START
TOMORROW WILL FAVOR TEMPERATURES CLIMBING CLOSE THE AGREEABLE MOS
NUMBERS.
MODELS STILL SHOW THAT LOW LEVEL MOISTURE WILL STREAM NORTHWARD
INTO OUR AREA TOMORROW...SO SHOULD SEE AN INCREASE IN MOISTURE AND
CLOUDS. DID GO WITH SPOTTY DRIZZLE OVER CENTRAL MO INTO WEST
CENTRAL IL WHERE MODEL CROSS SECTIONS ARE SHOWING DEEP LOW LEVEL
MOISTURE WITH SOME WEAK ASCENT. BETTER CHANCE OF MEASURABLE RAIN
WILL OCCUR TUESDAY NIGHT FROM SOUTHEASTERN MO INTO SOUTHERN IL
WHEN THERE WILL BE SOME MODEST LARGE SCALE ASCENT ON THE TAIL END
OF A GREAT LAKES TROUGH.
THERE IS SLIGHTLY BETTER CONTINUITY AND AGREEMENT BETWEEN THE GFS/
ECMWF/CANADIAN GEM THAN 24 HOURS AGO...THOUGH THERE ARE STILL
ENOUGH DIFFERENCES TO MAKE FOR A LOW CONFIDENCE FORECAST FOR LATE
WEEK INTO NEXT WEEKEND. WITH THIS SAID...IT DOES LOOK LIKE THERE
WILL BE A STORM SYSTEM MOVING ACROSS MO/IL EARLY NEXT WEEKEND THAT
WILL HAVE ENOUGH COLD AIR TO PROVIDE AT LEAST A MIX OF RAIN/SNOW
ON FRIDAY NIGHT AND SATURDAY. 00Z OPERATIONAL GFS DEPICTS A
DEFORMATION ZONE THAT WOULD PRODUCE A BAND OF SNOW OVER THE
CENTRAL PART OF THE CWA DURING THIS PERIOD...BUT IT IS FASTER AND
MORE NORTH WITH THIS SYSTEM THAN THE OTHER MODELS...INCLUDING MOST
OF THE GFS ENSEMBLE MEMBERS. FOR NOW WILL JUST MENTION A CHANCE OF
RAIN AND SNOW AND SEE WHAT FUTURE MODELS RUNS DEPICT.
BRITT/KANOFSKY
&&
.AVIATION...
/1154 AM CST MON JAN 30 2012/
PRIMARY CONCERN TODAY WILL BE CROSSWINDS WITH PERSISTENT SOUTHWEST
FLOW GUSTING TO 25KTS. GUSTS WILL SUBSIDE THIS EVENING BUT WIND
WILL STAY BETWEEN 12-15KTS. WIND WILL INCREASE WITH HEIGHT TO
AROUND 40-45KTS FROM THE WEST-SOUTHWEST AT AROUND 2000FT...BUT
INCREASE SHOULD BE GRADUAL ENOUGH THAT LLWS SHOULD BE MARGINAL AT
WORST. MOISTURE FROM THE GULF WILL EVENTUALLY MAKE IT UP INTO THE
REGION TUESDAY MORNING AND AM EXPECTING A STRATUS DECK TO MOVE IN
BETWEEN 10Z-14Z AND OVERSPREAD THE AREA. UNSURE WHAT THE HEIGHT OF
THE DECK WILL BE AT THIS TIME BUT MOST LIKELY HEIGHT LOOKS TO BE
BETWEEN 2500-3500FT.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS WILL PREVAIL AT LAMBERT THIS
AFTERNOON...HOWEVER SOUTHWEST FLOW RIGHT AROUND 210 DEGREES WILL
PRODUCE A DIRECT CROSSWIND ACROSS THE MAIN RUNWAYS. GUSTS WILL
SUBSIDE THIS EVENING BUT WIND WILL STAY BETWEEN 12-15KTS. WIND
WILL INCREASE WITH HEIGHT TO AROUND 40-45KTS FROM THE WEST-
SOUTHWEST AT AROUND 2000FT...BUT INCREASE SHOULD BE GRADUAL ENOUGH
THAT LLWS SHOULD BE MARGINAL AT WORST. EXPECTING A STRATUS DECK
TO MOVE IN BETWEEN AFTER 12Z AND OVERSPREAD THE AREA. TIMING AND
HEIGHT OF THE DECK IS STILL UNCERTAIN BUT MOST LIKELY HEIGHT
LOOKS TO BE BETWEEN 3500-4000FT WITH TIMING AROUND 15Z. COULD SEE
SOME LIGHT RAIN DEVELOP LATE TUESDAY AFTERNOON OR EARLY
EVENING...BUT THE BEST CHANCE OF PRECIP WILL BE EAST OF THE TERMINAL.
CARNEY
&&
.FIRE WEATHER...
WILL MENTION AN INCREASED FIRE DANGER TODAY OVER PARTS OF CENTRAL
AND SOUTHEAST MISSOURI. NOT MUCH CHANGE TO PREVIOUS FORECAST
THINKING. SOUTHWEST WINDS WILL BRING IN SLIGHTLY MORE MOISTURE
THROUGH THE DAY...BUT TEMPERATURES NEARING RECORDS WILL STILL
FORCE MINIMUM RELATIVELY HUMIDITY VALUES INTO THE 25-30 PERCENT
RANGE. THIS SAME AREA WILL ALSO HAVE SUSTAINED 20FT WINDS IN THE
10-15 MPH RANGE WITH HIGHER GUSTS. TEN HOUR FUELS WILL LIKELY FALL
BELOW 10 PERCENT IN THIS SAME AREA. HOWEVER AS MENTIONED IN THE
PREVIOUS DISCUSSION...RECENT COLLABORATION WITH THE USFS SUGGESTS
THAT DEAD FUELS MAY BE DRY ON TOP...BUT BE DAMP JUST BELOW THE
SURFACE WHICH WOULD GREATLY REDUCE THE RISK OF UNCONTROLLED FIRES
IN SPITE OF OTHER FACTORS. THE DRIEST PART OF THE AREA...CENTRAL
AND SOUTHEAST MISSOURI...RECEIVED MEASURABLE PRECIPITATION AS
RECENTLY AS 3 DAYS AGO...AND THOSE AREAS HAVE HAD AS MUCH AS AN
INCH OR MORE WITHIN THE PAST COUPLE OF WEEKS. BY TOMORROW...LOW
LEVEL MOISTURE WILL INCREASE ENOUGH TO END RISK OF WILDFIRES.
BRITT/CARNEY
&&
.CLIMATE...
RECORD HIGHS FOR MONDAY JANUARY 30TH
KSTL 67 IN 1884
KCOU 68 IN 1890
RECORD HIGH LOW TEMPERATURES FOR JANUARY 31ST
KSTL 53 IN 1877
KCOU 46 IN 1923
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
532 AM CST MON JAN 30 2012
.DISCUSSION...
/323 AM CST MON JAN 30 2012/
MAIN CONCERNS ARE WELL ABOVE NORMAL TEMPERATURES THE NEXT TWO DAYS AND
THEN CHANCES FOR SNOW LATE THIS WEEK INTO NEXT WEEKEND.
STILL BELIEVE WE WILL BE IN RECORD TEMPERATURE TERRITORY TODAY GIVEN
THE MOSTLY SUNNY SKIES AND SOUTHWEST WINDS WHICH ARE TYPICALLY A
WARM UP WIND. RUC SOUNDINGS DO SHOW AN INVERSION AROUND 900MB
WHICH WILL LIMIT MIXING HEIGHTS TODAY...HOWEVER THE TEMPERATURES
AT THIS LEVEL WILL BE AROUND +10C WHICH STILL FAVORS HIGHS
REACHING THE LOWER TO MIDDLE 60S OVER MUCH OF THE AREA. THESE
VALUES MATCH THE MOS TEMPS REASONABLY WELL. SURFACE PRESSURE
GRADIENT WILL REMAIN TIGHT ENOUGH TONIGHT TO PREVENT MUCH OF A DROP
OFF IN WIND SPEED...AND HENCE SHOULD KEEP LOWS FROM FALLING MUCH
BELOW NORMAL DAYTIME HIGHS FOR THE END OF JANUARY. THE WARM START
TOMORROW WILL FAVOR TEMPERATURES CLIMBING CLOSE THE AGREEABLE MOS
NUMBERS.
MODELS STILL SHOW THAT LOW LEVEL MOISTURE WILL STREAM NORTHWARD
INTO OUR AREA TOMORROW...SO SHOULD SEE AN INCREASE IN MOISTURE AND
CLOUDS. DID GO WITH SPOTTY DRIZZLE OVER CENTRAL MO INTO WEST
CENTRAL IL WHERE MODEL CROSS SECTIONS ARE SHOWING DEEP LOW LEVEL
MOISTURE WITH SOME WEAK ASCENT. BETTER CHANCE OF MEASURABLE RAIN
WILL OCCUR TUESDAY NIGHT FROM SOUTHEASTERN MO INTO SOUTHERN IL
WHEN THERE WILL BE SOME MODEST LARGE SCALE ASCENT ON THE TAIL END
OF A GREAT LAKES TROUGH.
THERE IS SLIGHTLY BETTER CONTINUITY AND AGREEMENT BETWEEN THE GFS/
ECMWF/CANADIAN GEM THAN 24 HOURS AGO...THOUGH THERE ARE STILL
ENOUGH DIFFERENCES TO MAKE FOR A LOW CONFIDENCE FORECAST FOR LATE
WEEK INTO NEXT WEEKEND. WITH THIS SAID...IT DOES LOOK LIKE THERE
WILL BE A STORM SYSTEM MOVING ACROSS MO/IL EARLY NEXT WEEKEND THAT
WILL HAVE ENOUGH COLD AIR TO PROVIDE AT LEAST A MIX OF RAIN/SNOW
ON FRIDAY NIGHT AND SATURDAY. 00Z OPERATIONAL GFS DEPICTS A
DEFORMATION ZONE THAT WOULD PRODUCE A BAND OF SNOW OVER THE
CENTRAL PART OF THE CWA DURING THIS PERIOD...BUT IT IS FASTER AND
MORE NORTH WITH THIS SYSTEM THAN THE OTHER MODELS...INCLUDING MOST
OF THE GFS ENSEMBLE MEMBERS. FOR NOW WILL JUST MENTION A CHANCE OF
RAIN AND SNOW AND SEE WHAT FUTURE MODELS RUNS DEPICT.
BRITT/KANOFSKY
&&
.AVIATION...
/520 AM CST MON JAN 30 2012/
VFR CONDITIONS EXPECTED TODAY WITH SWLY WINDS GUSTING TO AROUND
25 KTS BY LATE MORNING DUE TO DIURNAL MIXING. THE PRESSURE
GRADIENT SHOULD REMAIN TIGHT ENOUGH OVERNIGHT TO KEEP WINDS FROM
FALLING BELOW 8-12KTS. MODELS SHOW INCREASING MOISTURE LATE
TONIGHT AHEAD OF A SHORTWAVE WHICH WILL PROBABLY CAUSE A STRATUS
OR STRATOCU DECK TO SPREAD NWD HOWEVER CONFIDENCE IN MVFR CIGS
REMAINS TOO LOW TO MENTION IN THE TAFS ATTM.
SPECIFICS FOR KSTL...VFR CONDITIONS EXPECTED TODAY WITH SWLY WINDS
GUSTING TO AROUND 25 KTS BY LATE MORNING DUE TO DIURNAL MIXING.
THE PRESSURE GRADIENT SHOULD REMAIN TIGHT ENOUGH OVERNIGHT TO KEEP
WINDS FROM FALLING BELOW 8-12KTS. MODELS SHOW INCREASING MOISTURE
LATE TONIGHT AHEAD OF A SHORTWAVE WHICH WILL PROBABLY CAUSE A
STRATUS OR STRATOCU DECK TO SPREAD NWD HOWEVER CONFIDENCE IN MVFR
CIGS REMAINS TOO LOW TO MENTION IN THE KSTL TAF ATTM.
KANOFSKY
&&
.FIRE WEATHER...
WILL MENTION AN INCREASED FIRE DANGER TODAY OVER PARTS OF CENTRAL
AND SOUTHEAST MISSOURI. NOT MUCH CHANGE TO PREVIOUS FORECAST
THINKING. SOUTHWEST WINDS WILL BRING IN SLIGHTLY MORE MOISTURE
THROUGH THE DAY...BUT TEMPERATURES NEARING RECORDS WILL STILL
FORCE MINIMUM RELATIVELY HUMIDITY VALUES INTO THE 25-30 PERCENT
RANGE. THIS SAME AREA WILL ALSO HAVE SUSTAINED 20FT WINDS IN THE
10-15 MPH RANGE WITH HIGHER GUSTS. TEN HOUR FUELS WILL LIKELY FALL
BELOW 10 PERCENT IN THIS SAME AREA. HOWEVER AS MENTIONED IN THE
PREVIOUS DISCUSSION...RECENT COLLABORATION WITH THE USFS SUGGESTS
THAT DEAD FUELS MAY BE DRY ON TOP...BUT BE DAMP JUST BELOW THE
SURFACE WHICH WOULD GREATLY REDUCE THE RISK OF UNCONTROLLED FIRES
IN SPITE OF OTHER FACTORS. THE DRIEST PART OF THE AREA...CENTRAL
AND SOUTHEAST MISSOURI...RECEIVED MEASURABLE PRECIPITATION AS
RECENTLY AS 3 DAYS AGO...AND THOSE AREAS HAVE HAD AS MUCH AS AN
INCH OR MORE WITHIN THE PAST COUPLE OF WEEKS. BY TOMORROW...LOW
LEVEL MOISTURE WILL INCREASE ENOUGH TO END RISK OF WILDFIRES.
BRITT/CARNEY
&&
.CLIMATE...
RECORD HIGHS FOR MONDAY JANUARY 30TH
KSTL 67 IN 1884
KCOU 68 IN 1890
RECORD HIGH LOW TEMPERATURES FOR JANUARY 31ST
KSTL 53 IN 1877
KCOU 46 IN 1923
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
323 AM CST MON JAN 30 2012
.DISCUSSION...
/323 AM CST MON JAN 30 2012/
MAIN CONCERNS ARE WELL ABOVE NORMAL TEMPERATURES THE NEXT TWO DAYS AND
THEN CHANCES FOR SNOW LATE THIS WEEK INTO NEXT WEEKEND.
STILL BELIEVE WE WILL BE IN RECORD TEMPERATURE TERRITORY TODAY GIVEN
THE MOSTLY SUNNY SKIES AND SOUTHWEST WINDS WHICH ARE TYPICALLY A
WARM UP WIND. RUC SOUNDINGS DO SHOW AN INVERSION AROUND 900MB
WHICH WILL LIMIT MIXING HEIGHTS TODAY...HOWEVER THE TEMPERATURES
AT THIS LEVEL WILL BE AROUND +10C WHICH STILL FAVORS HIGHS
REACHING THE LOWER TO MIDDLE 60S OVER MUCH OF THE AREA. THESE
VALUES MATCH THE MOS TEMPS REASONABLY WELL. SURFACE PRESSURE
GRADIENT WILL REMAIN TIGHT ENOUGH TONIGHT TO PREVENT MUCH OF A DROP
OFF IN WIND SPEED...AND HENCE SHOULD KEEP LOWS FROM FALLING MUCH
BELOW NORMAL DAYTIME HIGHS FOR THE END OF JANUARY. THE WARM START
TOMORROW WILL FAVOR TEMPERATURES CLIMBING CLOSE THE AGREEABLE MOS
NUMBERS.
MODELS STILL SHOW THAT LOW LEVEL MOISTURE WILL STREAM NORTHWARD
INTO OUR AREA TOMORROW...SO SHOULD SEE AN INCREASE IN MOISTURE AND
CLOUDS. DID GO WITH SPOTTY DRIZZLE OVER CENTRAL MO INTO WEST
CENTRAL IL WHERE MODEL CROSS SECTIONS ARE SHOWING DEEP LOW LEVEL
MOISTURE WILL SOME WEAK ASCENT. BETTER CHANCE OF MEASUREABLE RAIN
WILL OCCUR TUESDAY NIGHT FROM SOUTHEASTERN MO INTO SOUTHERN IL
WHEN THERE WILL BE SOME MODEST LARGE SCALE ASCENT ON THE TAIL END
OF A GREAT LAKES TROUGH.
THERE IS SLIGHTLY BETTER CONTINUITY AND AGREEMENT BETWEEN THE GFS/
ECMWF/CANADIAN GEM THAN 24 HOURS AGO...THOUGH THERE ARE STILL
ENOUGH DIFFERENCES TO MAKE FOR A LOW CONFIDENCE FORECAST FOR LATE
WEEK INTO NEXT WEEKEND. WITH THIS SAID...IT DOES LOOK LIKE THERE
WILL BE A STORM SYSTEM MOVE ACROSS MO/IL EARLY NEXT WEEKEND THAT
WILL HAVE ENOUGH COLD AIR TO PROVIDE AT LEAST A MIX OF RAIN/SNOW
ON FRIDAY NIGHT AND SATURDAY. 00Z OPERATIONAL GFS DEPICTS A
DEFORMATION ZONE THAT WOULD PRODUCE A BAND OF SNOW OVER THE
CENTRAL PART OF THE CWA DURING THIS PERIOD...BUT IT IS FASTER AND
MORE NORTH WITH THIS SYSTEM THAN THE OTHER MODELS...INCLUDING
MOST OF THE GFS ENSEMBLE MEMBERS. FOR NOW WILL JUST MENTION A
CHANCE OF RAIN AND SNOW AND SEE WHAT FUTURE MODELS RUNS DEPICT.
BRITT/KANOFKSY
&&
.AVIATION...
/1012 PM CST SUN JAN 29 2012/
MID-HIGH LEVEL CLOUDINESS WILL CONTINUE TO ADVECT SEWD THROUGH
THE TAF SITES LATE TGT. THE MODELS WERE SHOWING MID LEVEL
CLOUDINESS...MOISTURE CENTERED AROUND 700 MB...DROPPING SEWD
THROUGH THE AREA LATE TGT...ESPECIALLY UIN AREA DUE TO STRONG
LOW-MID LEVEL WAA. SELY SFC WINDS WILL GRADUALLY INCREASE IN SPEED
LATE TGT...THEN VEER AROUND TO A SLY DIRECTION BY EARLY MRNG...AND
SWLY AND GUSTY ON MON AFTER THE PASSAGE OF A WARM FRONT LATE TGT.
THERE WILL BE SOME LLWS IN UIN EARLY MON MRNG DUE TO A WLY LOW
LEVEL JET OVER IA AND NRN IL BUT IT DOES NOT APPEAR TO BE STRONG
ENOUGH TO INCLUDE IN THE UIN TAF. JUST HIGH LEVEL CLOUDINESS ON
MON.
SPECIFICS FOR KSTL...HIGH LEVEL CLOUDINESS THIS FORECAST PERIOD
WITH MID LEVEL CLOUDS AROUND 10000 FT MAINLY LATE TGT. SELY
SFC WIND WILL VEER AROUND TO A SLY DIRECTION BY EARLY MRNG...THEN
STRONGER AND GUSTY FROM A SWLY DIRECTION ON MON. S-SWLY SFC WNDS
WILL CONTINUE MON NGT. LOW LEVEL MOISTURE WILL BE INCREASING LATE
MON NGT BUT IT DOES NOT LOOK LIKE LOW LEVEL CLOUD COVER WILL
DEVELOP OR ADVECT INTO STL UNTIL AFTER THE TAF FORECAST PERIOD.
GKS
&&
.FIRE WEATHER...
WILL MENTION AN INCREASED FIRE DANGER TODAY OVER PARTS OF CENTRAL
AND SOUTHEAST MISSOURI. NOT MUCH CHANGE TO PREVIOUS FORECAST
THINKING. SOUTHWEST WINDS WILL BRING IN SLIGHTLY MORE MOISTURE
THROUGH THE DAY...BUT TEMPERATURES NEARING RECORDS WILL STILL
FORCE MINIMUM RELATIVELY HUMIDITY VALUES INTO THE 25-30 PERCENT
RANGE. THIS SAME AREA WILL ALSO HAVE SUSTAINED 20FT WINDS IN THE
10-15 MPH RANGE WITH HIGHER GUSTS. TEN HOUR FUELS WILL LIKELY FALL
BELOW 10 PERCENT IN THIS SAME AREA. HOWEVER AS MENTIONED IN THE
PREVIOUS DISCUSSION...RECENT COLLABORATION WITH THE USFS SUGGESTS
THAT DEAD FUELS MAY BE DRY ON TOP...BUT BE DAMP JUST BELOW THE
SURFACE WHICH WOULD GREATLY REDUCE THE RISK OF UNCONTROLLED FIRES
INSPITE OF OTHER FACTORS. THE DRIEST PART OF THE AREA...CENTRAL
AND SOUTHEAST MISSOURI...RECEIVED MEASURABLE PRECIPITATION AS
RECENTLY AS 3 DAYS AGO...AND THOSE AREAS HAVE HAD AS MUCH AS AN
INCH OR MORE WITHIN THE PAST COUPLE OF WEEKS. BY TOMORROW...LOW
LEVEL MOISTURE WILL INCREASE ENOUGH TO END RISK OF WILDFIRES.
BRITT/CARNEY
&&
.CLIMATE...
RECORD HIGHS FOR MONDAY JANUARY 30TH
KSTL 67 IN 1884
KCOU 68 IN 1890
RECORD HIGH LOW TEMPERATURES FOR JANUARY 31ST
KSTL 53 IN 1877
KCOU 46 IN 1923
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
301 PM MST MON JAN 30 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...
A WEST TO NORTHWEST FLOW RESIDES OVER THE AREA WITH A WEAK
DISTURBANCE MOVING EAST THROUGH MONTANA TODAY. RADAR ECHOES OVER
THE STATE HAVE BEEN SPOTTY IN THE PAST 12 TO 18 HOURS BUT SOME
INCREASES ARE SHOWING UP IN NORTH-CENTRAL MONTANA AND A BIT INTO
THE WESTERN AND CENTRAL ZONES EARLY THIS AFTERNOON.
THESE ECHOES ARE EXPECTED TO INCREASE IN INTENSITY INTO THE LATE
AFTERNOON THEN BEGIN TO DIMINISH THIS EVENING. THE NAM AND GFS
SHOW IT TO HIT MAINLY THE CENTRAL ZONES...AND HAVE INCREASED POPS
ACCORDINGLY. THE HRRR SHOWED IT PRODUCE THE GREATEST QPF OVER THE
SE ZONES THAN THE GFS. HAVE LEANED MORE WITH THE GFS THOUGH BASED
ON RECENT PERFORMANCE. THE NAM HAS BEEN MUCH TOO WET WITH RECENT
SYSTEMS. ALBEIT BRIEF...THE SYSTEM LOOKS INTENSE WITH MOST OF THE
LIFT OCCURRING JUST ABOVE 700 MB AND WHERE TEMPS ARE AROUND -15C
(AND GOOD DENDREDIC GROWTH). PRECIP TYPE LOOKS TRICKY WITH MODEL
NAM SOUNDINGS SHOWING A POSSIBLE MIX WITH SNOW WHILE THE GFS IS
WARMER AND KEEPS THE PRECIP ALL LIQUID.
SYSTEM PASSES OFF TO OUR SOUTHEAST TONIGHT. WITH POSSIBLE WET
ROADWAYS...CLEARING SKIES AND TEMPS DROPPING BELOW FREEZING...ICY
ROADS ARE A GOOD POSSIBILITY. HAVE HIGHLIGHTED THIS IN AN HWO.
AFTERWARDS...IT LOOKS TO REMAIN PARTLY CLOUDY WITH CONTINUED ABOVE
NORMAL TEMPS. WENT ABOVE MAV AND MET GUIDANCE ON TEMPS...CLOSER
TO BIAS CORRECTED NUMBERS. CLOUDS LOOK TO BEGIN INCREASING
WEDNESDAY AFTERNOON WITH THE NEXT SYSTEM COMING IN. JAMBA
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
MORE SPRING-LIKE WEATHER IN THE OFFING. IN THE MIDST OF AN
AMPLIFYING PATTERN...THE LAST IN A SERIES OF SHORTWAVES MOVES SE
ACROSS THE AREA WED NIGHT...WITH SOME SPLITTING MOTION THOUGH. WILL
RAISE POPS TO A SLIGHT CHANCE OF SNOW SHOWERS.
THEN...AN UNUSUALLY STRONG UPPER RIDGE TAKES HOLD OVER THE WESTERN
STATES...THEN CLOSING OFF A CENTER OVER THE NORTHERN ROCKIES TO
THE PACIFIC NW. THIS GIVES SEVERAL DAYS OF DRY AND MAINLY SUNNY
WEATHER...WITH WINDS ON THE LIGHT SIDE. TEMPS LIKELY TO REMAIN
WELL ABOVE NORMAL WITH THICKNESSES OFTEN IN THE 540S DM...BUT 850
MB FORECAST TEMPS AND MODEL SPECTRUM DO SHOW SIGNIFICANT
DIFFERENCES...SEEMING TO INDICATE POSSIBLE STRONG INVERSIONS.
WITHOUT SNOWCOVER THOUGH...PREFER TO STAY ON THE WARM SIDE OF
GUIDANCE.
LATE IN THE PERIOD...SIGNS OF THE RIDGE SHARPENING...AND A LITTLE
FARTHER W. THIS MAY ALLOW AN ARCITC COLD FRONT FROM THE N TO
BRUSH OUR AREA. MUCH MODEL DIFFERENCE ON TIMING...BEING ANYWHERE
FROM SUNDAY TO TUESDAY...AND ON INTENSITY OF THE FRONT AND UPPER
SUPPORT AS WELL. THEREFORE AM STAYING CONSERVATIVE AS IT IS STILL
OUT THERE ON DAYS 6 TO 8. SIMONSEN
PREVIOUS LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... MODELS
CONTINUE TO INDICATE TRANSITION FROM ZONAL PATTERN TO A HIGH
AMPLITUDE BLOCKING PATTERN EARLY IN THE EXTENDED PERIOD. NEW
WRINKLE IS TAKING THE SHORTWAVE DROPPING THROUGH THE GREAT BASIN
WEDNESDAY/WEDNESDAY NIGHT AND DEVELOPING A CLOSED LOW OVER THE
SOUTHWEST STATES. RIDGE STILL EXPECTED OVER THE NORTHERN ROCKIES
BUT WILL GET CLOSED OR PINCHED OFF BY LOW TO THE SOUTH AND TROF IN
THE EAST PACIFIC.
INITIAL PUSH OF WARM AIR INTO THE REGION WITH RIDGE WILL GRADUALLY
MODERATE AS SHORTWAVES PUSH THROUGH THE TOP OF THE RIDGE. OVERALL
STILL EXPECTING WELL ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. EBERT
&&
.AVIATION...
CEILINGS LOWERING TO AROUND 4K FT AGL OVERCAST LATE THIS AFTERNOON AND
EVENING WITH RAIN SHOWERS DEVELOPING AND MOVING E. THESE WILL
LIKELY TURN TO SNOW SHOWERS THIS EVENING BEFORE ENDING...WHICH
COULD REDUCE VISIBILITY TO 2 TO 4 MILES AND CEILINGS TO 2-3K FT AGL
FOR A SHORT TIME. VFR WITH SCATTERED TO BROKEN LAYERS ABOVE 8K FT
AGL FOR TUE. SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
924 AM MST MON JAN 30 2012
.SHORT TERM...VALID FOR TDY AND TUE...
UPDATE TO ZFP AND NO UPDATE TO WRKAFP. SITES AROUND KLVM WERE
OCCASIONALLY HITTING WIND ADVISORY CRITERIA THIS MORNING DUE TO
TIGHT N-S ORIENTED PRESSURE GRADIENT OVER KLVM AND THE BEARTOOTH
FOOTHILLS. STILLWATER MINE JUST UNDER ADVISORY CRITERIA PER RECENT
REPORT. WILL CONTINUE THE ADVISORY AND RE-EVALUATE WITH THE
AFTERNOON PACKAGE. WILL NEED TO WATCH BIG TIMBER AS GRADIENT WAS
FORECAST ON 12Z WRF TO BECOME REORIENTED W TO E WHICH FAVORS THIS
SITE FOR STRONG WINDS.
250 MB JET COUPLET SEEN IN RUC DATE WAS BRINGING UPPER DIVERGENCE TO
WESTERN AREAS THIS MORNING. IN ADDITION...STRONG VORTICITY MAXIMUM
SEEN ON WATER VAPOR IMAGERY WILL MOVE THROUGH THE AREA THROUGH EARLY
THIS EVENING. MOIST WESTERLY FLOW WILL ACCOMPANY THE SYSTEM. COOKE
CITY WEB CAMS SHOWED ACCUMULATING SNOW THIS MORNING AND SNOW OVER
THE CRAZY MOUNTAINS COULD BE INFERRED FROM THE BIG TIMBER WEBCAM.
SNOTELS WERE NOT SHOWING MUCH IN THE WAY OF ACCUMULATION THROUGH 8
AM MST...BUT BASED ON WEBCAMS AND THE ABOVE FACTORS...HAVE INCREASED
POPS OVER W-FACING SLOPES OF THE BEARTOOTHS/ABSAROKAS AND OVER THE
CRAZYS AS WELL. ECHOES ON RADAR OVER THE PLAINS WERE LIKELY JUST
ALTOCUMULUS AT THIS POINT GIVEN HIGH TEMPERATURE/DEWPOINT SPREADS.
BULK OF THE MOISTURE WILL BE OVER NE MT THIS AFTERNOON...SO WILL
LEAVE THE DRY FORECAST FOR THE PLAINS. MOISTURE WILL MOVE SE THIS
EVENING...SUPPORTING THE GOING POPS. WINDS AND TEMPERATURES WERE IN
GOOD SHAPE BASED ON EXPECTED MIXING. ARTHUR
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
A SHORTWAVE WILL MOVE ACROSS THE REGION WEDNESDAY NIGHT THROUGH
THURSDAY. THE STRONGEST FORCING WILL TRACK SOUTH OF THE CWA SO
KEPT POPS LOW. AN UPPER-LEVEL RIDGE WILL BUILD OVER THE REGION
THROUGH THE REST OF THE EXTENDED PERIOD. ABOVE AVERAGE
TEMPERATURES AND DRY CONDITIONS WILL PREVAIL. BLENDED INHERITED
MAX/MIN TEMPS WITH THE BEST-PERFORMING 00Z GUIDANCE...BCCONSMOS
AND CONSRAW RESPECTIVELY. BRS
&&
.AVIATION...
VFR AND WINDY CONDITIONS WILL PREVAIL TODAY. A FEW SHOWERS WILL
BE POSSIBLE OVER THE MOUNTAINS AND MAY BRIEFLY IMPACT KLVM.
MOUNTAIN OBSCURATIONS ARE EXPECTED TODAY. SCATTERED SHOWERS WILL
BE POSSIBLE GENERALLY AROUND KMLS TO KBHK LATE TONIGHT INTO EARLY
TUESDAY MORNING. BRIEF MVFR/IFR CONDITIONS WILL BE POSSIBLE.
CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 054 031/047 027/047 029/044 025/047 023/053 029/051
1/N 20/B 01/B 20/B 00/U 00/U 00/U
LVM 050 029/044 033/046 024/042 018/049 021/052 028/054
3/W 21/N 12/W 21/B 00/B 00/U 00/U
HDN 052 026/047 021/048 028/049 021/048 020/053 024/055
1/N 30/B 01/B 20/B 01/U 00/U 00/U
MLS 052 026/044 020/044 027/043 023/044 021/048 024/050
1/B 30/B 01/B 10/B 01/B 00/U 00/U
4BQ 052 027/043 023/045 026/044 022/046 020/050 024/051
1/E 30/B 01/B 21/B 11/B 00/U 00/U
BHK 051 025/043 019/044 025/040 021/042 021/048 022/048
1/B 30/B 00/B 11/B 10/B 00/U 00/U
SHR 053 023/042 018/045 023/040 020/045 020/048 026/050
1/E 20/B 01/B 21/B 01/B 00/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 6 PM MST THIS EVENING FOR ZONES
65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
842 AM MST MON JAN 30 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
UPPER DISTURBANCE ON THE WATER VAPOR UP OVER EAST CENTRAL BRITISH
COLUMBIA IS DROPPING SOUTHEAST INTO ALBERTA. MODELS ARE HINTING AT
SOME INSTABILITY TO GENERATE SHOWERS AS THE DISTURBANCE DROPS IN
THIS AFTERNOON. TEMPS GENERALLY LOOK TOO WARM FOR SNOW. GENERALLY
FOLLOWED THE 06Z GFS FOR POPS AND QPF AS THE 12Z NAM LOOKS TOO WET
(WHICH HAS BEEN THE CASE LATELY). REST OF FORECAST LOOKED GOOD.
ALSO ADDED MENTION OF RECORD HIGH TEMP FOR THE GLASGOW AREA TODAY.
RECORD MAX LOW TEMPERATURE LOOKS TO BE IN JEOPARDY TODAY. JAMBA
PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A LITTLE MORE
PROGRESSIVE AND OVERALL ACTIVE CONUS WEATHER PATTERN TODAY. THE
HUDSON BAY UPPER LOW IS PINWHEELING THE LAST REMNANTS OF ITS
EMBEDDED UPPER LEVEL SHORT WAVE TROUGH THROUGH THE NEW ENGLAND
STATES WHILE BEING WEAKENED BY ENCROACHING LARGE SCALE RIDGING
FROM THE WEST. EMBEDDED WITHIN THIS BROAD AND WEAK UPPER RIDGING
OVER THE CENTRAL AND WESTERN PORTIONS OF CANADA AND OUR CONUS...IS
A SHORT WAVE TROUGH HAVING ALREADY MOVED ONSHORE OVER THE PACIFIC
NORTHWEST.
THIS APPROACHING STORM SYSTEM FROM THE WEST TODAY IS PUSHING AMPLE
MOISTURE OVER THE CONTINENTAL DIVIDE AND ACROSS THE STATE OF MONTANA.
FORECAST CHALLENGES WILL INCLUDE THE TIMING AND TYPE OF
PRECIPITATION WITH THE STORM SYSTEM LASTING FROM LATE THIS MORNING
THROUGH EARLY TUESDAY MORNING.
SHORT TERM OPERATIONAL MODEL SOLUTIONS SHOW MODERATE AGREEMENT
WITH A BAND OF RAIN SHOWERS DESCENDING SOUTHEASTWARD FROM THE
CANADIAN ROCKIES AND THROUGH NORTHEAST MONTANA THROUGH THE LATTER
PART OF THE DAY TODAY AND INTO EARLY TUESDAY MORNING. CURRENT AND
EXPECTED WARM TEMPERATURES WILL KEEP MOST OF THE INITIAL
PRECIPITATION AS RAIN. BEGINNING THIS EVENING...A RAIN AND SNOW
MIX WILL BE POSSIBLE...FOLLOWED BY A CHANGE OVER TO ALL SNOW AFTER
MIDNIGHT AS THE SYSTEM MAKES A QUICK EXIT TO THE EAST.
RECENT MODEL PERFORMANCE WOULD SUGGEST FAVORING THE GFS OVER THE
NAM WITH SOME INFLUENCE FROM THE HRRR MODEL. THE NAM MAY DO WELL
WITH TIMING AND PLACEMENT...BUT HAS BEEN OVERLY WET. AS THE GFS
HAS COME INTO PLACEMENT AGREEMENT...THE LESSER QPF AMOUNTS
ADVERTISED BY IT MAY BE THE MORE ACCURATE SOLUTION. AS THE LAST
STORM SYSTEM RESULTED IN VERY LITTLE PRECIPITATION AT THE
SURFACE...IF ANY AT ALL...I KEPT THE STORM SYSTEM FOR TODAY
RELATIVELY DRY...ALBEIT 0.01 TO 0.04 INCHES OF PRECIP FOR ANY
GIVEN 6 HOUR PERIOD OF TIME. THIS SEEMS TO BE GENEROUS ENOUGH
UNTIL WE ACTUALLY SEE OBSERVATIONAL DATA TO THE CONTRARY.
TUESDAY WILL DAWN BRIGHT WITH CLEARING FROM THE WEST. THIS WILL
SIGNAL THE BEGINNING OF A SERIES OF QUICKLY PASSING SHORT WAVE
TROUGHS AND RIDGES SET TO MOVE THROUGH MONTANA THROUGH THE MIDDLE
OF THE WEEK. NONE OF THE TROUGHS APPEAR TO HAVE ENOUGH MOISTURE
AND LIFT TO GENERATE ANY PRECIP AT THIS TIME. KEPT THIS PART OF
THE FORECAST DRY. BMICKELSON
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
MODELS CONTINUE TO INDICATE TRANSITION FROM ZONAL PATTERN TO A
HIGH AMPLITUDE BLOCKING PATTERN EARLY IN THE EXTENDED PERIOD. NEW
WRINKLE IS TAKING THE SHORTWAVE DROPPING THROUGH THE GREAT BASIN
WEDNESDAY/WEDNESDAY NIGHT AND DEVELOPING A CLOSED LOW OVER THE
SOUTHWEST STATES. RIDGE STILL EXPECTED OVER THE NORTHERN ROCKIES
BUT WILL GET CLOSED OR PINCHED OFF BY LOW TO THE SOUTH AND TROF
IN THE EAST PACIFIC.
INITIAL PUSH OF WARM AIR INTO THE REGION WITH RIDGE WILL GRADUALLY
MODERATE AS SHORTWAVES PUSH THROUGH THE TOP OF THE RIDGE. OVERALL
STILL EXPECTING WELL ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. EBERT
&&
.AVIATION...
VFR WITH MID TO HIGH CLOUDS THROUGH TODAY. A PACIFIC DISTURBANCE
WILL MOVE THROUGH THE REGION TODAY WHICH COULD BRING SOME LOWER
CLOUDS AND POSSIBLY SHOWERS LATE IN THE DAY. RAE
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
350 AM MST MON JAN 30 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A LITTLE MORE
PROGRESSIVE AND OVERALL ACTIVE CONUS WEATHER PATTERN TODAY. THE
HUDSON BAY UPPER LOW IS PINWHEELING THE LAST REMNANTS OF ITS
EMBEDDED UPPER LEVEL SHORT WAVE TROUGH THROUGH THE NEW ENGLAND
STATES WHILE BEING WEAKENED BY ENCROACHING LARGE SCALE RIDGING
FROM THE WEST. EMBEDDED WITHIN THIS BROAD AND WEAK UPPER RIDGING
OVER THE CENTRAL AND WESTERN PORTIONS OF CANADA AND OUR CONUS...IS
A SHORT WAVE TROUGH HAVING ALREADY MOVED ONSHORE OVER THE PACIFIC NORTHWEST.
THIS APPROACHING STORM SYSTEM FROM THE WEST TODAY IS PUSHING AMPLE
MOISTURE OVER THE CONTINENTAL DIVIDE AND ACROSS THE STATE OF MONTANA.
FORECAST CHALLENGES WILL INCLUDE THE TIMING AND TYPE OF
PRECIPITATION WITH THE STORM SYSTEM LASTING FROM LATE THIS MORNING
THROUGH EARLY TUESDAY MORNING.
SHORT TERM OPERATIONAL MODEL SOLUTIONS SHOW MODERATE AGREEMENT
WITH A BAND OF RAIN SHOWERS DESCENDING SOUTHEASTWARD FROM THE
CANADIAN ROCKIES AND THROUGH NORTHEAST MONTANA THROUGH THE LATTER
PART OF THE DAY TODAY AND INTO EARLY TUESDAY MORNING. CURRENT AND
EXPECTED WARM TEMPERATURES WILL KEEP MOST OF THE INITIAL
PRECIPITATION AS RAIN. BEGINNING THIS EVENING...A RAIN AND SNOW
MIX WILL BE POSSIBLE...FOLLOWED BY A CHANGE OVER TO ALL SNOW AFTER
MIDNIGHT AS THE SYSTEM MAKES A QUICK EXIT TO THE EAST.
RECENT MODEL PERFORMANCE WOULD SUGGEST FAVORING THE GFS OVER THE
NAM WITH SOME INFLUENCE FROM THE HRRR MODEL. THE NAM MAY DO WELL
WITH TIMING AND PLACEMENT...BUT HAS BEEN OVERLY WET. AS THE GFS
HAS COME INTO PLACEMENT AGREEMENT...THE LESSER QPF AMOUNTS
ADVERTISED BY IT MAY BE THE MORE ACCURATE SOLUTION. AS THE LAST
STORM SYSTEM RESULTED IN VERY LITTLE PRECIPITATION AT THE
SURFACE...IF ANY AT ALL...I KEPT THE STORM SYSTEM FOR TODAY
RELATIVELY DRY...ALBEIT 0.01 TO 0.04 INCHES OF PRECIP FOR ANY
GIVEN 6 HOUR PERIOD OF TIME. THIS SEEMS TO BE GENEROUS ENOUGH
UNTIL WE ACTUALLY SEE OBSERVATIONAL DATA TO THE CONTRARY.
TUESDAY WILL DAWN BRIGHT WITH CLEARING FROM THE WEST. THIS WILL
SIGNAL THE BEGINNING OF A SERIES OF QUICKLY PASSING SHORT WAVE
TROUGHS AND RIDGES SET TO MOVE THROUGH MONTANA THROUGH THE MIDDLE
OF THE WEEK. NONE OF THE TROUGHS APPEAR TO HAVE ENOUGH MOISTURE
AND LIFT TO GENERATE ANY PRECIP AT THIS TIME. KEPT THIS PART OF
THE FORECAST DRY. BMICKELSON
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
MODELS CONTINUE TO INDICATE TRANSITION FROM ZONAL PATTERN TO A
HIGH AMPLITUDE BLOCKING PATTERN EARLY IN THE EXTENDED PERIOD. NEW
WRINKLE IS TAKING THE SHORTWAVE DROPPING THROUGH THE GREAT BASIN
WEDNESDAY/WEDNESDAY NIGHT AND DEVELOPING A CLOSED LOW OVER THE
SOUTHWEST STATES. RIDGE STILL EXPECTED OVER THE NORTHERN ROCKIES
BUT WILL GET CLOSED OR PINCHED OFF BY LOW TO THE SOUTH AND TROF
IN THE EAST PACIFIC.
INITIAL PUSH OF WARM AIR INTO THE REGION WITH RIDGE WILL GRADUALLY
MODERATE AS SHORTWAVES PUSH THROUGH THE TOP OF THE RIDGE. OVERALL
STILL EXPECTING WELL ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. EBERT
&&
.AVIATION...
VFR WITH MID TO HIGH CLOUDS THROUGH TODAY. A PACIFIC DISTURBANCE
WILL MOVE THROUGH THE REGION TODAY WHICH COULD BRING SOME LOWER
CLOUDS AND POSSIBLY SHOWERS LATE IN THE DAY. RAE
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...COR SYNOPSIS
NWS WILMINGTON NC
822 AM EST MON JAN 30 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL MOVE OFFSHORE OF THE CAROLINAS
TUESDAY. A WARMING TREND WILL FOLLOW THROUGH MID WEEK. A COLD FRONT
WILL PASS ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY WITH UNSETTLED
WEATHER POSSIBLY PREVAILING INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 620 AM MONDAY...THE UPPER TROF ACROSS THE FA WILL DE-AMPLIFY
AS IT PUSHES EAST. THIS WILL LEAVE RATHER ZONAL FLOW ALOFT...WITH
FLOW FROM THE W TO WNW DIRECTION...THRU THE ATM COLUMN WITH THE
EXCEPTION IN THE BOUNDARY LAYER. MODELS PROG THE MOVEMENT OF THE SFC
HIGHS RATHER TIGHT CENTER ACROSS THE CAROLINAS TODAY...AND JUST
OFFSHORE FROM THE CAROLINAS TONIGHT. WITH THE SUBSIDENCE...SHOULD
SEE WIDESPREAD DEWPOINTS IN THE 20S WITH A FEW UPPER TEENS POSSIBLE.
PROGGED MEAN RHS THRU THE ATM COLUMN REMAIN QUITE LOW AND WILL
CONTINUE THE CLEAR FORECAST THRUOUT THE NEAR TERM. BASICALLY NEUTRAL
ADVECTION TODAY WITH MODEL MOS GUIDANCE IN GOOD AGREEMENT WITH HIGHS
IN THE UPPER 50S TO LOW 60S. FOR TONIGHT...WAA ALOFT TO DEVELOP AND
CAN BE WITNESSED WITH MODEL 8H TEMPS AND 1K-8H THICKNESSES BOTH
INCREASING. HOWEVER...THE SFC BASED INVERSION DEVELOPING AFTER
SUNSET...WILL RESULT IN WINDS DECOUPLING. THIS WILL PREVENT THE WAA
JUST OFF THE DECK FROM MIXING DOWN TO THE SFC. AS A RESULT...HAVE
GONE BELOW MODEL MOS GUIDANCE WITH TONIGHTS LOWS...WITH LOWS
STRADDLING THE 32 DEGREE MARK AWAY FROM THE COAST.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...DRY PROGRESSIVE FLOW ALOFT AND SURFACE RIDGING
WILL WORK TO KEEP THE AREA DRY THROUGH THE PERIOD. INITIALLY LOW
LEVEL FLOW IS LIGHT AND VARIABLE BUT BY TUE AFTERNOON THE SURFACE
RIDGE AXIS SHIFTS OFFSHORE AND RETURN FLOW SETS UP. WARM ADVECTION
WILL LEAD TO INCREASING TEMPERATURES AND DEW POINTS...BUT DEEP DRY
AIR KEEPS SKIES NEARLY CLOUD FREE. HIGHS WILL CLIMB INTO THE MID TO
UPPER 60S WITH SOUTHERLY FLOW TUE NIGHT KEEPING LOWS IN THE LOW TO
MID 40S.
WEAK 5H RIDGE BUILDS NORTH WED AS SURFACE RIDGE SHIFTS FARTHER
OFFSHORE. THE 00Z NAM/GFS MOVE AN AREA OF POSITIVE VORTICITY...BORN
OF CONVECTION...NORTH INTO THE SOUTHEAST US AND INTERACT IT WITH
WEAK SHORTWAVE TROUGH EJECTING OUT OF THE WEST. THE ECMWF/CANADIAN
MINIMIZE THE INTERACTION OF THE FEATURE WITH THE WEAK 5H TROUGH AND
MOVE IT EAST ACROSS NORTHERN FL. GIVEN THE KNOWN TENDENCY FOR
CONVECTIVE FEEDBACK WITHIN THE GFS/NAM HAVE CHOSEN TO FAVOR THE
ECMWF/CANADIAN SOLUTIONS. THE RESULT IS A DRY WARM FORECAST WITH
SOME CLOUD COVER SPREADING NORTH LATE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...EXTENDED FORECAST REMAINS CLOUDED IN MYSTERY.
THE 00Z GFS IS NOT SHOWING MUCH CONTINUITY FROM ITS 12Z 1/29 RUN AND
ITS BASICALLY THE SAME STORY FOR THE ECMWF AND THE CANADIAN. AT THIS
POINT CANNOT SEE HOW CONFIDENCE COULD BE ANY LOWER. THE MAIN ISSUE
IS THE EVOLUTION OF THE UPPER PATTERN AND THE IMPACT THIS HAS ON
SHORTWAVE EJECTING FROM THE SOUTHWEST LATE IN THE WEEK. THE 00Z GFS
REMAINS MORE PROGRESSIVE THAN THE 00Z ECMWF/CANADIAN BUT IS SLOWER
AND MORE AMPLIFIED THAN ITS PREVIOUS 12Z RUN. THE 00Z ECMWF NOW
KEEPS THE 5H LOW CUTOFF OVER THE SOUTHWEST WITH 5H RIDGE BUILDING IN
THE EAST...A SOLUTION THE CANADIAN DOES APPEAR TO BE TRENDING TOWARD
AND A PATTERN THAT HAS BEEN SEEN BEFORE THIS WINTER.
NOW LOOKS LIKE FRI WILL END UP DRIER...SO WENT AHEAD AND CUT BACK
POP FRI/FRI NIGHT. COLD FRONT MOVES ACROSS THE AREA THU NIGHT INTO
FRI BUT LACKS ANY SIGNIFICANT COLD ADVECTION. IT ALSO APPEARS A
PORTION OF THE WEEKEND WILL BE WET...FOR NOW THAT LOOKS TO BE SAT
INTO SUN BUT AGAIN WITH SUCH LOW CONFIDENCE CANNOT SEE GOING ABOVE
30 PERCENT AT THIS TIME. TEMPERATURES ABOVE TO WELL ABOVE CLIMO
EARLY IN THE PERIOD...BUT COULD SEE A 10 DEGREE OR MORE SWING IN
TEMPERATURES DEPENDING ON HOW THE PATTERN EVOLVES. FOR NOW FAVORED
THE PROGRESSIVE SOLUTION WHICH WOULD PRODUCE COOLER...NEAR
CLIMO...TEMPERATURES LATE IN THE PERIOD.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...VFR EXPECTED THROUGH THE TAF VALID PERIOD WITH ONLY
SCATTERED CIRRUS EXPECTED.
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL BE MOVING ACROSS THE
TERMINALS TODAY. EXPECT WEST TO NORTHWEST WINDS THIS MORNING TO
BECOME SOUTHWEST AT FLO/LBT BY EARLY AFTERNOON...AND SOUTHEAST AT
THE ILM/CRE/MYR TERMINALS MID-LATE AFTERNOON.
THIS EVENING WITH GOOD RADIATIONAL COOLING A LOW-LEVEL INVERSION
WILL QUICKLY SET UP WHICH SHOULD ALLOW FOR WINDS TO BECOME CALM OR
LIGHT AND VARIABLE BY EARLY EVENING. RADIATIONAL COOLING WILL BE
MAXIMIZED AND WILL NEED TO MONITOR THE CRE TERMINAL DURING THE
EARLY EVENING FOR VISIBILITY REDUCTIONS IN BR AS SOME LOW-LEVEL
MOISTURE INCREASE IS LIKELY DUE TO ONSHORE FLOW THIS AFTERNOON.
EXTENDED OUTLOOK...LOW CONFIDENCE FOR FOG WEDNESDAY MORNING. LOW
CONFIDENCE FOR IFR ASSOCIATED WITH PRECIPITATION THURSDAY. VFR
FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 620 AM MONDAY...NO ADVISORIES OR CAUTION FLAGS FOR THE NEAR
TERM.
WINDS ACROSS THE ILM WATERS WILL BE GOVERNED BY SFC HIGH PRESSURE.
THE CENTER OF THIS HIGH TO MIGRATE EAST TO THE COASTAL CAROLINAS
TODAY. IT WILL CONTINUE TO RIDGE BACK ACROSS THE LOCAL WATERS AS IT
MOVES JUST OFFSHORE TONIGHT. WHAT THIS ALL SPELLS IS FOR WINDS TO
DIMINISH TO 10 KT OR LESS WHILE VEERING FROM THE NW TO N BY MID
AFTERNOON VIA THE LATEST HRRR RUNS. FOR TONIGHT...HAVE INDICATED A
DOMINATE SOUTHERLY WIND LESS THAN 10 KT. WOULD NOT BE SURPRISED TO
OBSERVE A VARIABLE WIND DIRECTION AT TIMES TONIGHT DUE TO THE HIGHS
CENTER IN CLOSE PROXIMITY. WAVEWATCH3 INDICATES A LESS THAN 1 FT 9+
SECOND ESE GROUND SWELL TO COMBINE WITH A 2 TO 4 SECOND PERIOD WIND
WAVES...AND PRODUCE SIGNIFICANT SEAS OF 2 FT OR LESS THROUGH THE
PERIOD.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...ELONGATED SURFACE RIDGE AXIS OVER THE WATERS
EARLY TUE WILL SHIFT OFFSHORE DURING TUE. WILL SEE A SLIGHT INCREASE
IS SOUTHWEST FLOW BY AFTERNOON...BUT SPEEDS SHOULD STILL BE NO MORE
THAN 10 KT WITH THE EXCEPTION BEING RIGHT ALONG THE COAST WHERE SEA
BREEZE WILL INCREASE SPEEDS AND LEAD TO ONSHORE FLOW. MUCH THE SAME
STORY EXPECTED FOR WED ALTHOUGH LATE WED/WED NIGHT A COLD FRONT
DROPPING INTO THE CAROLINAS/TN VALLEY WILL PINCH THE GRADIENT A
BIT...BUMPING SOUTHWEST TO 10 TO 15 KT. SEAS AROUND 2 FT TUE WILL
BUILD TO 2 TO 3 FT WED AND A SOLID 3 FT WED NIGHT.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...BENIGN CONDITIONS EXPECTED THU AND FRI. LATE THU
SOUTHWEST FLOW MAY TOUCH 15 KT WITH GRADIENT TIGHTENING UP AS WEAK
FRONT INCHES CLOSER. WEAK COLD FRONT MOVES ACROSS THE WATERS EARLY
FRI WITH LIGHT NORTHERLY FLOW DEVELOPING. SEAS BRIEFLY BUILD TO 3 TO
4 FT LATE THU WITH INCREASING SOUTHWEST FLOW BUT DROP BACK TO 2 TO 3
FT ONCE NORTHERLY FLOW SETS UP.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/8
SHORT TERM...III
LONG TERM...III
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
620 AM EST MON JAN 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE ITS EASTWARD PROGRESSION THROUGH THE
SOUTHEAST...MOVING OVERHEAD ON LATER TODAY. THIS HIGH PRESSURE
SYSTEM WILL SHIFT OFF THE COAST BY TUESDAY...MOVING FARTHER OFF
SHORE THROUGH MID WEEK. A COLD FRONT WILL MOVE THROUGH THURSDAY
NIGHT INTO FRIDAY WITH UNSETTLED WEATHER POSSIBLY CONTINUING
THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 620 AM MONDAY...THE UPPER TROF ACROSS THE FA WILL DE-AMPLIFY
AS IT PUSHES EAST. THIS WILL LEAVE RATHER ZONAL FLOW ALOFT...WITH
FLOW FROM THE W TO WNW DIRECTION...THRU THE ATM COLUMN WITH THE
EXCEPTION IN THE BOUNDARY LAYER. MODELS PROG THE MOVEMENT OF THE SFC
HIGHS RATHER TIGHT CENTER ACROSS THE CAROLINAS TODAY...AND JUST
OFFSHORE FROM THE CAROLINAS TONIGHT. WITH THE SUBSIDENCE...SHOULD
SEE WIDESPREAD DEWPOINTS IN THE 20S WITH A FEW UPPER TEENS POSSIBLE.
PROGGED MEAN RHS THRU THE ATM COLUMN REMAIN QUITE LOW AND WILL
CONTINUE THE CLEAR FORECAST THRUOUT THE NEAR TERM. BASICALLY NEUTRAL
ADVECTION TODAY WITH MODEL MOS GUIDANCE IN GOOD AGREEMENT WITH HIGHS
IN THE UPPER 50S TO LOW 60S. FOR TONIGHT...WAA ALOFT TO DEVELOP AND
CAN BE WITNESSED WITH MODEL 8H TEMPS AND 1K-8H THICKNESSES BOTH
INCREASING. HOWEVER...THE SFC BASED INVERSION DEVELOPING AFTER
SUNSET...WILL RESULT IN WINDS DECOUPLING. THIS WILL PREVENT THE WAA
JUST OFF THE DECK FROM MIXING DOWN TO THE SFC. AS A RESULT...HAVE
GONE BELOW MODEL MOS GUIDANCE WITH TONIGHTS LOWS...WITH LOWS
STRADDLING THE 32 DEGREE MARK AWAY FROM THE COAST.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...DRY PROGRESSIVE FLOW ALOFT AND SURFACE RIDGING
WILL WORK TO KEEP THE AREA DRY THROUGH THE PERIOD. INITIALLY LOW
LEVEL FLOW IS LIGHT AND VARIABLE BUT BY TUE AFTERNOON THE SURFACE
RIDGE AXIS SHIFTS OFFSHORE AND RETURN FLOW SETS UP. WARM ADVECTION
WILL LEAD TO INCREASING TEMPERATURES AND DEW POINTS...BUT DEEP DRY
AIR KEEPS SKIES NEARLY CLOUD FREE. HIGHS WILL CLIMB INTO THE MID TO
UPPER 60S WITH SOUTHERLY FLOW TUE NIGHT KEEPING LOWS IN THE LOW TO
MID 40S.
WEAK 5H RIDGE BUILDS NORTH WED AS SURFACE RIDGE SHIFTS FARTHER
OFFSHORE. THE 00Z NAM/GFS MOVE AN AREA OF POSITIVE VORTICITY...BORN
OF CONVECTION...NORTH INTO THE SOUTHEAST US AND INTERACT IT WITH
WEAK SHORTWAVE TROUGH EJECTING OUT OF THE WEST. THE ECMWF/CANADIAN
MINIMIZE THE INTERACTION OF THE FEATURE WITH THE WEAK 5H TROUGH AND
MOVE IT EAST ACROSS NORTHERN FL. GIVEN THE KNOWN TENDENCY FOR
CONVECTIVE FEEDBACK WITHIN THE GFS/NAM HAVE CHOSEN TO FAVOR THE
ECMWF/CANADIAN SOLUTIONS. THE RESULT IS A DRY WARM FORECAST WITH
SOME CLOUD COVER SPREADING NORTH LATE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...EXTENDED FORECAST REMAINS CLOUDED IN MYSTERY.
THE 00Z GFS IS NOT SHOWING MUCH CONTINUITY FROM ITS 12Z 1/29 RUN AND
ITS BASICALLY THE SAME STORY FOR THE ECMWF AND THE CANADIAN. AT THIS
POINT CANNOT SEE HOW CONFIDENCE COULD BE ANY LOWER. THE MAIN ISSUE
IS THE EVOLUTION OF THE UPPER PATTERN AND THE IMPACT THIS HAS ON
SHORTWAVE EJECTING FROM THE SOUTHWEST LATE IN THE WEEK. THE 00Z GFS
REMAINS MORE PROGRESSIVE THAN THE 00Z ECMWF/CANADIAN BUT IS SLOWER
AND MORE AMPLIFIED THAN ITS PREVIOUS 12Z RUN. THE 00Z ECMWF NOW
KEEPS THE 5H LOW CUTOFF OVER THE SOUTHWEST WITH 5H RIDGE BUILDING IN
THE EAST...A SOLUTION THE CANADIAN DOES APPEAR TO BE TRENDING TOWARD
AND A PATTERN THAT HAS BEEN SEEN BEFORE THIS WINTER.
NOW LOOKS LIKE FRI WILL END UP DRIER...SO WENT AHEAD AND CUT BACK
POP FRI/FRI NIGHT. COLD FRONT MOVES ACROSS THE AREA THU NIGHT INTO
FRI BUT LACKS ANY SIGNIFICANT COLD ADVECTION. IT ALSO APPEARS A
PORTION OF THE WEEKEND WILL BE WET...FOR NOW THAT LOOKS TO BE SAT
INTO SUN BUT AGAIN WITH SUCH LOW CONFIDENCE CANNOT SEE GOING ABOVE
30 PERCENT AT THIS TIME. TEMPERATURES ABOVE TO WELL ABOVE CLIMO
EARLY IN THE PERIOD...BUT COULD SEE A 10 DEGREE OR MORE SWING IN
TEMPERATURES DEPENDING ON HOW THE PATTERN EVOLVES. FOR NOW FAVORED
THE PROGRESSIVE SOLUTION WHICH WOULD PRODUCE COOLER...NEAR
CLIMO...TEMPERATURES LATE IN THE PERIOD.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...VFR EXPECTED THROUGH THE TAF VALID PERIOD WITH ONLY
SCATTERED CIRRUS EXPECTED.
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL BE MOVING ACROSS THE
TERMINALS TODAY. EXPECT WEST TO NORTHWEST WINDS THIS MORNING TO
BECOME SOUTHWEST AT FLO/LBT BY EARLY AFTERNOON...AND SOUTHEAST AT
THE ILM/CRE/MYR TERMINALS MID-LATE AFTERNOON.
THIS EVENING WITH GOOD RADIATIONAL COOLING A LOW-LEVEL INVERSION
WILL QUICKLY SET UP WHICH SHOULD ALLOW FOR WINDS TO BECOME CALM OR
LIGHT AND VARIABLE BY EARLY EVENING. RADIATIONAL COOLING WILL BE
MAXIMIZED AND WILL NEED TO MONITOR THE CRE TERMINAL DURING THE
EARLY EVENING FOR VISIBILITY REDUCTIONS IN BR AS SOME LOW-LEVEL
MOISTURE INCREASE IS LIKELY DUE TO ONSHORE FLOW THIS AFTERNOON.
EXTENDED OUTLOOK...LOW CONFIDENCE FOR FOG WEDNESDAY MORNING. LOW
CONFIDENCE FOR IFR ASSOCIATED WITH PRECIPITATION THURSDAY. VFR
FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 620 AM MONDAY...NO ADVISORIES OR CAUTION FLAGS FOR THE NEAR
TERM.
WINDS ACROSS THE ILM WATERS WILL BE GOVERNED BY SFC HIGH PRESSURE.
THE CENTER OF THIS HIGH TO MIGRATE EAST TO THE COASTAL CAROLINAS
TODAY. IT WILL CONTINUE TO RIDGE BACK ACROSS THE LOCAL WATERS AS IT
MOVES JUST OFFSHORE TONIGHT. WHAT THIS ALL SPELLS IS FOR WINDS TO
DIMINISH TO 10 KT OR LESS WHILE VEERING FROM THE NW TO N BY MID
AFTERNOON VIA THE LATEST HRRR RUNS. FOR TONIGHT...HAVE INDICATED A
DOMINATE SOUTHERLY WIND LESS THAN 10 KT. WOULD NOT BE SURPRISED TO
OBSERVE A VARIABLE WIND DIRECTION AT TIMES TONIGHT DUE TO THE HIGHS
CENTER IN CLOSE PROXIMITY. WAVEWATCH3 INDICATES A LESS THAN 1 FT 9+
SECOND ESE GROUND SWELL TO COMBINE WITH A 2 TO 4 SECOND PERIOD WIND
WAVES...AND PRODUCE SIGNIFICANT SEAS OF 2 FT OR LESS THROUGH THE
PERIOD.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...ELONGATED SURFACE RIDGE AXIS OVER THE WATERS
EARLY TUE WILL SHIFT OFFSHORE DURING TUE. WILL SEE A SLIGHT INCREASE
IS SOUTHWEST FLOW BY AFTERNOON...BUT SPEEDS SHOULD STILL BE NO MORE
THAN 10 KT WITH THE EXCEPTION BEING RIGHT ALONG THE COAST WHERE SEA
BREEZE WILL INCREASE SPEEDS AND LEAD TO ONSHORE FLOW. MUCH THE SAME
STORY EXPECTED FOR WED ALTHOUGH LATE WED/WED NIGHT A COLD FRONT
DROPPING INTO THE CAROLINAS/TN VALLEY WILL PINCH THE GRADIENT A
BIT...BUMPING SOUTHWEST TO 10 TO 15 KT. SEAS AROUND 2 FT TUE WILL
BUILD TO 2 TO 3 FT WED AND A SOLID 3 FT WED NIGHT.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...BENIGN CONDITIONS EXPECTED THU AND FRI. LATE THU
SOUTHWEST FLOW MAY TOUCH 15 KT WITH GRADIENT TIGHTENING UP AS WEAK
FRONT INCHES CLOSER. WEAK COLD FRONT MOVES ACROSS THE WATERS EARLY
FRI WITH LIGHT NORTHERLY FLOW DEVELOPING. SEAS BRIEFLY BUILD TO 3 TO
4 FT LATE THU WITH INCREASING SOUTHWEST FLOW BUT DROP BACK TO 2 TO 3
FT ONCE NORTHERLY FLOW SETS UP.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH
SHORT TERM...III
LONG TERM...III
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
321 AM EST MON JAN 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE ITS EASTWARD PROGRESSION THROUGH THE
SOUTHEAST...MOVING OVERHEAD ON LATER TODAY. THIS HIGH PRESSURE
SYSTEM WILL SHIFT OFF THE COAST BY TUESDAY...MOVING FARTHER OFF
SHORE THROUGH MID WEEK. A COLD FRONT WILL MOVE THROUGH THURSDAY
NIGHT INTO FRIDAY WITH UNSETTLED WEATHER POSSIBLY CONTINUING
THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM MONDAY...THE UPPER TROF ACROSS THE FA WILL DE-AMPLIFY
AS IT PUSHES EAST. THIS WILL LEAVE RATHER ZONAL FLOW ALOFT...
BASICALLY FROM THE W TO WNW DIRECTION THRU THE ATM COLUMN...WITH
THE EXCEPTION IN THE BOUNDARY LAYER. MODELS PROG THE MOVEMENT OF
THE HIGHS RATHER TIGHT CENTER ACROSS THE CAROLINAS TODAY...AND
JUST OFFSHORE FROM THE CAROLINAS TONIGHT. WITH THE SUBSIDENCE
SHOULD SEE WIDESPREAD DEWPOINTS IN THE 20S WITH A FEW UPPER TEENS
POSSIBLE. MEAN RHS THRU 5H REMAIN QUITE LOW AND WILL THEREFORE
CONTINUE THE CLEAR FORECAST THRUOUT THE NEAR TERM. BASICALLY
NEUTRAL ADVECTION TODAY WITH MODEL MOS GUIDANCE IN GOOD AGREEMENT
WITH HIGHS IN THE UPPER 50S TO LOW 60S. FOR TONIGHT...WAA ALOFT TO
DEVELOP AND CAN BE WITNESSED WITH MODEL 8H TEMPS AND 1K-8H
THICKNESSES BOTH INCREASING. HOWEVER...THE SFC BASED INVERSION
FOLLOWED BY WINDS DECOUPLING WILL OCCUR AFTER SUNSET. THIS WILL
PREVENT THE WAA JUST OFF THE DECK FROM MIXING DOWN TO THE SFC. AS
A RESULT...HAVE GONE BELOW MODEL MOS GUIDANCE WITH TONIGHTS
LOWS...WITH LOWS STRADDLING THE 32 DEGREE MARK.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...DRY PROGRESSIVE FLOW ALOFT AND SURFACE RIDGING
WILL WORK TO KEEP THE AREA DRY THROUGH THE PERIOD. INITIALLY LOW
LEVEL FLOW IS LIGHT AND VARIABLE BUT BY TUE AFTERNOON THE SURFACE
RIDGE AXIS SHIFTS OFFSHORE AND RETURN FLOW SETS UP. WARM ADVECTION
WILL LEAD TO INCREASING TEMPERATURES AND DEW POINTS...BUT DEEP DRY
AIR KEEPS SKIES NEARLY CLOUD FREE. HIGHS WILL CLIMB INTO THE MID TO
UPPER 60S WITH SOUTHERLY FLOW TUE NIGHT KEEPING LOWS IN THE LOW TO
MID 40S.
WEAK 5H RIDGE BUILDS NORTH WED AS SURFACE RIDGE SHIFTS FARTHER
OFFSHORE. THE 00Z NAM/GFS MOVE AN AREA OF POSITIVE VORTICITY...BORN
OF CONVECTION...NORTH INTO THE SOUTHEAST US AND INTERACT IT WITH
WEAK SHORTWAVE TROUGH EJECTING OUT OF THE WEST. THE ECMWF/CANADIAN
MINIMIZE THE INTERACTION OF THE FEATURE WITH THE WEAK 5H TROUGH AND
MOVE IT EAST ACROSS NORTHERN FL. GIVEN THE KNOWN TENDENCY FOR
CONVECTIVE FEEDBACK WITHIN THE GFS/NAM HAVE CHOSEN TO FAVOR THE
ECMWF/CANADIAN SOLUTIONS. THE RESULT IS A DRY WARM FORECAST WITH
SOME CLOUD COVER SPREADING NORTH LATE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...EXTENDED FORECAST REMAINS CLOUDED IN MYSTERY.
THE 00Z GFS IS NOT SHOWING MUCH CONTINUITY FROM ITS 12Z 1/29 RUN AND
ITS BASICALLY THE SAME STORY FOR THE ECMWF AND THE CANADIAN. AT THIS
POINT CANNOT SEE HOW CONFIDENCE COULD BE ANY LOWER. THE MAIN ISSUE
IS THE EVOLUTION OF THE UPPER PATTERN AND THE IMPACT THIS HAS ON
SHORTWAVE EJECTING FROM THE SOUTHWEST LATE IN THE WEEK. THE 00Z GFS
REMAINS MORE PROGRESSIVE THAN THE 00Z ECMWF/CANADIAN BUT IS SLOWER
AND MORE AMPLIFIED THAN ITS PREVIOUS 12Z RUN. THE 00Z ECMWF NOW
KEEPS THE 5H LOW CUTOFF OVER THE SOUTHWEST WITH 5H RIDGE BUILDING IN
THE EAST...A SOLUTION THE CANADIAN DOES APPEAR TO BE TRENDING TOWARD
AND A PATTERN THAT HAS BEEN SEEN BEFORE THIS WINTER.
NOW LOOKS LIKE FRI WILL END UP DRIER...SO WENT AHEAD AND CUT BACK
POP FRI/FRI NIGHT. COLD FRONT MOVES ACROSS THE AREA THU NIGHT INTO
FRI BUT LACKS ANY SIGNIFICANT COLD ADVECTION. IT ALSO APPEARS A
PORTION OF THE WEEKEND WILL BE WET...FOR NOW THAT LOOKS TO BE SAT
INTO SUN BUT AGAIN WITH SUCH LOW CONFIDENCE CANNOT SEE GOING ABOVE
30 PERCENT AT THIS TIME. TEMPERATURES ABOVE TO WELL ABOVE CLIMO
EARLY IN THE PERIOD...BUT COULD SEE A 10 DEGREE OR MORE SWING IN
TEMPERATURES DEPENDING ON HOW THE PATTERN EVOLVES. FOR NOW FAVORED
THE PROGRESSIVE SOLUTION WHICH WOULD PRODUCE COOLER...NEAR
CLIMO...TEMPERATURES LATE IN THE PERIOD.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE TAF
ISSUANCE PERIOD. CALM TO LIGHT W TO SW WINDS TONIGHT WILL BECOME NW
TO N AT 5 TO 10 KT AFTER SUNRISE BEFORE BACKING TO THE SW AND A
DURING THE AFTERNOON. WINDS ARE EXPECTED TO BECOME CALM OR VARIABLE
BY 2 KT AFTER SUNSET.
EXTENDED OUTLOOK...POTENTIAL MORNING FOG TUESDAY AND WEDNESDAY. LOW
CONFIDENCE FOR PRECIP ON THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM MONDAY...NO ADVISORIES OR CAUTION FLAGS FOR THE NEAR
TERM.
WINDS ACROSS THE ILM WATERS WILL BE GOVERNED BY SFC HIGH PRESSURE.
THE CENTER OF THIS HIGH TO MIGRATE EAST TO THE COASTAL CAROLINAS
TODAY. IT WILL CONTINUE TO RIDGE BACK ACROSS THE LOCAL WATERS AS IT
MOVES JUST OFFSHORE TONIGHT. WHAT THIS ALL SPELLS IS FOR WINDS TO
DIMINISH TO 10 KT OR LESS WHILE VEERING FROM THE NW TO N BY
EARLY TO MID AFTERNOON VIA THE LATEST HRRR RUN. FOR TONIGHT...HAVE
INDICATED A DOMINATE SOUTHERLY WIND 10 KT OR LESS. WOULD NOT BE
SURPRISED TO OBSERVE A VARIABLE WIND DIRECTION AT TIMES TONIGHT DUE
TO THE HIGHS CENTER IN CLOSE PROXIMITY. WAVEWATCH3 INDICATES A
LESS THAN 1 FT 9+ SECOND ESE GROUND SWELL TO COMBINE WITH A 2 TO 4
SECOND PERIOD WIND WAVES...AND PRODUCE SIGNIFICANT SEAS OF 2 FT OR
LESS THROUGH THE PERIOD.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...ELONGATED SURFACE RIDGE AXIS OVER THE WATERS
EARLY TUE WILL SHIFT OFFSHORE DURING TUE. WILL SEE A SLIGHT INCREASE
IS SOUTHWEST FLOW BY AFTERNOON...BUT SPEEDS SHOULD STILL BE NO MORE
THAN 10 KT WITH THE EXCEPTION BEING RIGHT ALONG THE COAST WHERE SEA
BREEZE WILL INCREASE SPEEDS AND LEAD TO ONSHORE FLOW. MUCH THE SAME
STORY EXPECTED FOR WED ALTHOUGH LATE WED/WED NIGHT A COLD FRONT
DROPPING INTO THE CAROLINAS/TN VALLEY WILL PINCH THE GRADIENT A
BIT...BUMPING SOUTHWEST TO 10 TO 15 KT. SEAS AROUND 2 FT TUE WILL
BUILD TO 2 TO 3 FT WED AND A SOLID 3 FT WED NIGHT.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...BENIGN CONDITIONS EXPECTED THU AND FRI. LATE THU
SOUTHWEST FLOW MAY TOUCH 15 KT WITH GRADIENT TIGHTENING UP AS WEAK
FRONT INCHES CLOSER. WEAK COLD FRONT MOVES ACROSS THE WATERS EARLY
FRI WITH LIGHT NORTHERLY FLOW DEVELOPING. SEAS BRIEFLY BUILD TO 3 TO
4 FT LATE THU WITH INCREASING SOUTHWEST FLOW BUT DROP BACK TO 2 TO 3
FT ONCE NORTHERLY FLOW SETS UP.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH
SHORT TERM...III
LONG TERM...III
AVIATION...DCH/RAN
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
850 PM CST TUE JAN 31 2012
.DISCUSSION...FORECAST CHALLENGE FOR UPDATE CONCERNS TEMPERATURES
AND CLOUD TRENDS/FOG. CLEARING CONTINUES TO PROGRESS EAST 15 KTS OR
SO WITH BACK EDGE OF CLOUDS ALONG RED RIVER. CURRENT TRENDS WOULD
HAVE CLEARING EAST OF FA A FEW HOURS AFTER MIDNIGHT. FOG MAIN
CONCERN WITH T/TD SPREAD TIGHT...LIGHT WINDS AND CLEARING. HAVE
ADDED FOG ALL AREAS OVERNIGHT WITH CLOUDS CONTINUING TO CLEAR. SOME
MID TEEN DEWPOINTS ACROSS FAR NW OTHERWISE DEWPOINTS HOLDING IN THE
MID TO UPPER 20S. RUC AND GFS BOTH HOLDING DEWPOINTS UP OVERNIGHT SO
WILL BE RAISING MINIMUMS UP A FEW DEGREES. WILL MAKE SOME MINOR
CLOUD TREND ADJUSTMENTS OTHERWISE CURRENT FORECAST GOOD.
&&
.AVIATION...
IFR/MVFR STRATUS DECK WILL CONTINUE TO MOVE SLOWLY EASTWARD THIS
EVENING AND OVERNIGHT. STILL EXPECT SOME MID-HIGH LEVEL CLOUD COVER
IN ADVANCE OF NEXT SHORT- WAVE. WITH CLEARING...LIGHT WINDS AND
TIGHT TEMPERATURE/DEWPOINT SPREAD WILL LIKELY SEE SOME BR OVERNIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
957 PM EST TUE JAN 31 2012
.SYNOPSIS...
MOISTURE INCREASES RAPIDLY IN THE OHIO VALLEY TONIGHT. WEAK COLD
FRONT WEDNESDAY WITH WAVE WEDNESDAY NIGHT. HIGH PRESSURE THURSDAY
NIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
UPDATED...
FCST GENERALLY ON TRACK. TRACKING AN UPPER LVL WAVE AND S/W TROF
AXIS...WELL AHEAD OF SFC FRONT. MODELS IN GOOD AGREEMENT WITH TIMING
AND FORCING WITH THIS. AS OF 02Z...SEEING SHRA BREAK OUT ACROSS KY
INTO CENTRAL OH WITH HELP OF STRENGTHENING LLJ AND LIFT IN MID
LVLS. USED A BLEND OF CURRENT POP GRIDS WITH HRRR MDL REFLECTIVITY
REMAINDER OF NIGHT. THIS TRACKS BAND OF SHRA THRU CWA...WEAKENING
ONCE TO MTNS PREDAWN. GIVEN AMNT OF DRY AIR IN LLVLS...SOME OF
THIS WILL HAVE A HARD TIME REACHING SFC INITIALLY.
THERE IS SOME MDL DISCREPANCY ON EXTENT OF PROGRESS INTO CWA BY
BAROCLINIC ZONE WEDNESDAY. MAY END UP PARKING IN SE OH OR ALONG OH
RVR WITH SUBSEQUENT SFC WAVE TRAVERSING BOUNDARY WEDNESDAY NIGHT.
PREVIOUS DISCUSSION BELOW...
DEW POINTS ARE EXPECTED TO INCREASE QUICKLY 00Z TO 06Z IN OUR
OHIO VALLEY COUNTIES AS MOISTURE STREAKS NE...UP THE RIVER VALLEY.
AREAS OF LIGHT RAIN SHOWERS EXPECTED TO DEVELOP INTO SOUTHEAST
OHIO...NORTHEAST KENTUCKY THIS EVENING.
FORECAST PROBLEM...IS HOW FAR EAST AND SOUTH DO THESE SHOWERS GET
LATE TONIGHT AND ON WEDNESDAY...BEFORE THE WEAK WAVE AFFECTS US
WEDNESDAY EVENING.
TRIED TO SLIDE THE LIKELY POP FOR SHOWERS EAST THROUGH CENTRAL WV
05Z TO 09Z...THEN INTO THE CENTRAL MOUNTAINS BEFORE DAWN.
DO NOT HAVE THE SURFACE FRONT INTO SOUTHEAST OHIO UNTIL 18Z
WEDNESDAY THEN TRIED TO HOLD NORTH OF A HTS-CRW LINE AT 00Z. THIS
IS A BIT FURTHER NORTH THAN THE 12Z NAM. SO HAVE POPS DROPPING OFF
A BIT DURING THE MORNING...BEFORE INCREASING AGAIN OVER SOUTHERN
COUNTIES DURING THE AFTERNOON...MAINLY HTS-CRW-EKN ON
SOUTH.
TRIED TO STAY MUCH WARMER THAN 12Z GFS MOS TEMPERATURE MINIMUM
TEMPERATURE GUIDANCE TONIGHT...FIGURING ON INCREASING CLOUD COVER
THIS EVENING.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
MODELS CONTINUE TO STRUGGLE WITH AGREEING ON THE DETAILS OF THE
SYSTEM FOR WEDNESDAY NIGHT INTO THURSDAY. NAM HAS TRENDED MORE
TOWARD THE GFS...BUT THE GFS IS NOT TOTALLY CONSISTENT WITH PREVIOUS
RUNS. CANADIAN DOES NOT DEVELOP THE WAVE MUCH...EXITING IT FAIRLY
FAST. DUE TO ALL THE UNCERTAINTY...WILL STAY TOWARD THE MIDDLE
GROUND FOR NOW.
LOW LEVEL WINDS LOOK TO BE CALM THURSDAY NIGHT. MOS GUIDANCE LOOKS A
BIT HIGH FOR A DECENT RADIATION NIGHT...SO WENT ON THE LOW SIDE OF
GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LOTS OF UNCERTAINTY IN THE LONG TERM PERIOD WITH LITTLE MODEL
AGREEMENT. 12Z ECMWF...ALONG WITH ITS 00Z PREDECESSOR...KEEP THE
AREA IN THE NORTHERN BRANCH OF SPLIT FLOW ALOFT OVER THE AREA...THUS
KEEPING A LOW PRESSURE SYSTEM AND ITS ASSOCIATED MOISTURE TO THE
SOUTH AND WEST OF THE AREA OVER THE WEEKEND. CANADIAN AND GFS KEEP
THE AREA IN THE SOUTHERN BRANCH OF THE FLOW...WITH GFS A BIT MORE
AGGRESSIVE WITH THE PROGRESSION OF THE LOW AND MOISTURE INTO OUR
REGION. FOR NOW...FOLLOWED HPC GRAPHICS...WHICH BROAD BRUSH POPS
ACROSS THE AREA...HOWEVER...BEST CHANCE FOR PRECIPITATION AT THIS
POINT DOES APPEAR TO BE THE SOUTHERN ZONES.
DUE TO THE OVERALL UNCERTAINTY...KEPT THE EXTENDED UNSETTLED UNTIL
MID WEEK WHEN HIGH PRESSURE TRIES TO REESTABLISH ITSELF OVER THE
REGION...RESULTING IN DRIER WEATHER.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
MOISTURE AND CEILINGS INCREASES QUICKLY AT THE 4 TO 7 THSD FT BKN
TO OVC LEVEL THROUGH 06Z. LIGHT RAIN SHOWERS POSSIBLE IN NORTHEAST
KENTUCKY...SOUTHEAST OHIO...AND WESTERN WEST VIRGINIA 00Z TO 06Z
WITH VSBY NEAR 5 MILES...REACHING INTO MOUNTAINOUS COUNTIES AFTER
05Z.
LLJ INCREASES TO NEAR 50KTS TONIGHT WITH H925 SPEEDS NEAR 40KTS.
WITH SOMEWHAT OF A NOCTURNAL INDUCED STABLE LYR NEAR SFC
DEVELOPING TONIGHT...HAVE CODED UP LLWS THRU 12Z FOR ALL SITES EXCEPT
KBKW.
KEPT MOST CEILINGS 2 TO 4 THSD FT BKN TO OVC WEDNESDAY NEAR FRONTAL
BOUNDARY ALONG WITH SOME SHRA WHICH MAY DIP VSBY INTO MVFR.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE AND TIMING OF RAIN SHOWERS IN QUESTION
WITH WEAK SUPPORT BUT INCREASING MOISTURE. LESS SHOWER COVERAGE
POSSIBLE OVERNIGHT THAN FORECAST. LLWS MAY BE MITIGATED SHOULD
MECHANICAL MIXING BECOME REALIZED ABSENT ANY STABLE LYR.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 02/01/12
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08
CRW CONSISTENCY H H H H H H M M M M H H
HTS CONSISTENCY H H H H M M M M M M H M
BKW CONSISTENCY H H H H H H H H H H M M
EKN CONSISTENCY H H H H H H L M M M M M
PKB CONSISTENCY H H H M M L L M M M H M
CKB CONSISTENCY H H H H H L M M M H H H
AFTER 00Z THURSDAY...
IFR POSSIBLE IN CEILINGS IN LOW LEVEL MOISTURE WEDNESDAY
NIGHT...LINGERING INTO THURSDAY MORNING IN THE MOUNTAINS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/SL/RPY
NEAR TERM...KTB/30
SHORT TERM...RPY
LONG TERM...SL
AVIATION...30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
543 PM EST MON JAN 30 2012
.SYNOPSIS...
A WARM FRONT WILL MOVE ACROSS THE STATE TONIGHT...USHERING IN VERY
MILD TEMPERATURES FOR MUCH OF THE WEEK. THE WEATHER WILL REMAIN
MAINLY DRY...EXCEPT FOR A CHANCE OF LIGHT SNOW SHOWERS TONIGHT IN
THE NORTHERN MOUNTAINS...AND SCATTERED RAIN SHOWERS WEDNESDAY AND
THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
HIGH PRESSURE OVER PENNSYLVANIA CEDES TO APPROACHING WARM FRONT
OVERNIGHT. WAA OVER GLAKES GENERATING JUST ENOUGH LIFT FOR A
NARROW AREA OF LIGHT SNOW. THIS WILL SLIDE EASTWARD THIS
EVENING...BRUSHING NORTHERN PA WITH JUST LIGHT ACCUMS AT MOST.
SW-W 850MB JET OF 50KTS NOSES IN FROM THE WEST WITH THE WARM FRONT
TONIGHT...LEADING THE PUSH OF MILDER AIR BACK INTO CENTRAL PA.
LOWS TONIGHT WILL ONLY DIP INTO THE MID AND UPPER 20S...AND WILL
LIKELY BEGIN TO SLOWLY RISE AFTER 06Z ACROSS THE WEST BEHIND
FROPA.
WARM FRONT BY TUE WILL BE ACROSS NY STATE...AND BROAD WSW FLOW
WILL KEEP PENNSYLVANIA DRY THRU TUESDAY. VERY MILD TEMPS WILL BE
SEEN AS 500MB HEIGHTS REACH 560 AND 850MB TEMPS RISE TO 5C+. THIS
SHOULD TRANSLATE INTO HIGHS TUESDAY APPROACHING 60F OVER SOME
SOUTHERN LOCATIONS...WITH UPPER 40S TO MID 50S FURTHER NORTH. THIS
WILL BE AS MUCH AS 15 TO 20 DEG ABOVE SEASONAL NORMS. WESTERLY
WINDS WILL BE BREEZY...ESP IN THE WESTERN HIGHER TERRAIN...BUT
NOTHING APPROACHING WHAT WE/VE SEEN OVER THE PAST COUPLE OF DAYS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A NRN STREAM SHORTWAVE TROUGH WILL PROGRESS EWD FROM THE NRN PLAINS
TO THE NORTHEAST TUE-WED. THE LOW-AMPLITUDE FAST-MOVG MID/UPPER
SYSTEM WILL BE ACCOMPANIED BY A WEAK SFC LOW TRACKING EWD ALONG THE
U.S./CANADIAN BORDER FROM MINNESOTA TO MAINE BY 0000 UTC 2 FEB 2012.
A BREEZY AND UNSEASONABLY MILD SWLY FLOW IN THE WARM SECTOR
PRECEDING THE TRAILING COLD FRONT WILL HELP BOOST TEMPERATURES
WELL-ABOVE CLIMATOLOGY /15-25 DEGREES/ PRIOR TO FROPA WHICH SHOULD
SLIDE NW-SE ACROSS THE COMMONWEALTH BY WED EVE. DESPITE FAIRLY
STRONG NEWD MOISTURE TRANSPORT INTO THE AREA VIA 40-50KT SWLY LLJ
THROUGH THE OH VALLEY...PCPN COVERAGE AND AMTS LOOK TO BE ON THE
LIGHTER SIDE GIVEN PROGRESSIVE NATURE OF THE SYSTEM...NWD
DISPLACEMENT OF BEST FORCING AND WEAK LOW-LEVEL CONVERGENCE. THE
SURFACE BOUNDARY WILL STALL-OUT NEAR OR SOUTH OF THE MASON DIXON
LINE AS THE FOCUS SHIFTS TO SPLIT FLOW TROUGH CROSSING THE PLAINS/MS
VLY AND ENTERING THE TN VLY/MID-ATLC REGION ON THURS. THIS FEATURE
SHOULD INDUCE A WEAK SFC WAVE TO TRACK EWD ALONG THE QUASI-STNRY
BAROCLINIC FRONTAL ZONE TO THE SOUTH OF PA.
CONCERNING THE FRONTAL WAVE FORECAST TO TRACK SOUTH OF PA WED
NGT-THURS...THE 12Z NAM IS THE MOST PROGRESSIVE SOLUTION THROUGHOUT
AND APPEARS TO BE AN OUTLIER COMPARED TO THE REST OF THE GUIDANCE.
THERE IS SLIGHT SPREAD WITH THE 12Z GFS/UKMET/ECMWF AND 00Z ECMWF ON
THE PROGRESSION BUT NOT AMPLIFICATION OF THE TROUGH AXIS HEADING
DOWNSTREAM. THE 12Z ECMWF DOES TREND A BIT WEAKER ALOFT WITH THIS
FEATURE THROUGH THE ERN PORTION OF THE COUNTRY BUT OVERALL NO LARGE
SCALE DIFFERENCES. HPC MODEL DIAGS PREFERRED A BLEND/COMPROMISE OF
THE OPERATIONAL GFS/UKMET AND ECMWF. THESE MODELS QPF FIELDS ARE IN
REASONABLY GOOD AGREEMENT SHOWING A RELATIVELY TIGHT GRADIENT OF
POSSIBLY ENHANCED PCPN ALONG/NORTH OF THE LOW TRACK FROM ERN KY ACRS
THE VIRGINIAS TO THE DELMARVA...AS UPPER LEVEL JET STREAK BECOMES
WELL-DEFINED. THIS SYSTEM SHOULD EXIT OFFSHORE THURS NGT AS HIGH
PRES OVERSPREADS THE REGION.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MEDIUM RANGE MODEL AND ENSEMBLE GUID STARTS THE PERIOD IN MUCH
BETTER AGREEMENT COMPARED TO YESTERDAY...SHOWING A HIGHLY AMPLIFIED
WEST COAST RIDGE/ROCKIES-PLAINS TROUGH CONFIGURATION WITH CONFLUENT
ZONAL FLOW DOWNSTREAM IN THE EAST. INDIVIDUAL SOLUTION SPREAD GROWS
QUICKLY IN TIME AND THE GUIDANCE BECOMES RATHER CHAOTIC WITH
VIRTUALLY NO RUN-TO-RUN CONSISTENCY. THE GFS/GEFS ARE QUICKER TO
EJECT THE PLAINS ENERGY EWD INTO THE OH VLY BY THE END OF THE PD
WHILE THE ECMWF LEAVES BEHIND SIGNIFICANT ENERGY IN THE SWRN CONUS.
GIVEN THE HIGH UNCERTAINTY IN THE EVOLUTION OF THE LARGE SCALE FLOW
FORECASTER CONFIDENCE REMAINS LOW. THEREFORE...THE LONG TERM GRIDS
WERE DERIVED USING A NEAR EQUAL BLEND OF HPC/GMOS AND GFS/ECMWF
GUIDANCE WHICH FAVORS NEAR TO ABOVE AVG TEMPERATURES AND A GRADUAL
INCREASE IN POPS FROM LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
A WARM FRONT OVR THE OHIO VALLEY WILL LIFT NORTHEAST THRU CENTRAL
PA LATE TONIGHT. JUST ENOUGH LIFT AHEAD OF THIS BOUNDARY TO
PRODUCE A BIT OF VERY LIGHT SNOW AT BFD EARLY THIS EVENING.
OTHERWISE...MDL DATA AND UPSTREAM OBS BOTH STRONGLY INDICATING
VFR CONDS OVERNIGHT WITH CLOUD BASES6666 ARND 10KFT. BIGGEST AVIATION
CONCERN TONIGHT WILL BE DEVELOPING LLWS...THE RESULT OF STRONG
WSWRLY LOW LVL JET OVERSPREADING THE AREA...IN CONJUNCTION WITH
MUCH LIGHTER SOUTHERLY WINDS AT GROUND LEVEL. LATEST RUC 0-0.5KM
BULK SHEAR SUGGESTS LLWS CRITERIA WILL BE MET BY ARND 02Z OVR THE
W MTNS...THEN REACHING THE SUSQ VALLEY LATER TONIGHT. SFC WARM
FRONT MAY WORK INTO JST BY ARND MIDNIGHT...RESULTING IN GUSTY SW
WINDS AND DIMINISHED LLWS THERE LATE TONIGHT.
FOR THE BULK OF CENTRAL PA...WARM FRONT WILL LIFT NORTH OF THE
AREA BY LATE AM...RESULTING IN A DECREASING THREAT OF LLWS BUT
INCREASING SW WINDS AT THE SFC GUSTING TO NR 25KTS. ALL MDL DATA
POINTING TOWARD A HIGH DEGREE OF CONFIDENCE IN VFR CONDS TUESDAY
WITH THE POSSIBLE EXCEPTION OF LATE DAY MVFR CIGS AT BFD.
OUTLOOK...
WED...SCT SHRA. LOW CIGS/SHRA POSSIBLE W MTNS. VFR ELSEWHERE.
THU...SCT SHRA. MVFR CIGS POSSIBLE.
FRI-SAT...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/RXR
NEAR TERM...RXR
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/RXR
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
546 PM CST TUE JAN 31 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT THROUGH WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A MOISTURE
STARVED LOW PRESSURE SYSTEM MOVING OVER THE CENTRAL UPPER PENINSULA
EARLY THIS AFTERNOON...AND ITS ASSOCIATED COOL FRONT PUSHING ACROSS
CENTRAL WISCONSIN. THE COLDER AIR IS LAGGING BEHIND THE FRONT AND
CAN BE MARKED BY THE LEADING EDGE OF A LOW STRATUS DECK THAT IS
SHIFTING SE OVER MINNESOTA AND ALMOST TO THE WI BORDER. DESPITE THE
SHALLOW NATURE OF THE LOW MOISTURE ON 12Z RAOBS...MIXING HAS NOT
DETERRED ITS PROGRESS SO FAR TODAY. WILL MAKE SOME LAST MINUTE
ADJUSTMENTS TO SPEED UP ITS FORWARD MOTION IF THIS CONTINUES TO BE
THE CASE. AS THESE CLOUDS ADVANCE TOWARDS NORTHERN
WISCONSIN...CLOUDS AND TEMPS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...LOW PRESSURE WILL CONTINUE TO TRACK TO THE EAST OVER THE
EASTERN UPPER PENINSULA INTO SOUTHEAST ONTARIO. MID AND HIGH CLOUDS
WILL DEPART THIS EVENING WITH THE ELONGATED SHORTWAVE TROUGH...BUT
PLENTY OF LOW CLOUDS UPSTREAM WILL SHIFT SE WITHIN A COOLER AIRMASS
WRAPPING AROUND THE LOW AND INTO THE NORTHERN HALF OF THE STATE.
ALTHOUGH THE MOISTURE IS SHALLOW AND SOME EROSION IS EXPECTED...THE
COOLER AIRMASS WILL PROMOTE ITS ADVANCEMENT ACROSS NORTH-CENTRAL AND
CENTRAL WISCONSIN TONIGHT. THINK DOWNSLOPING SHOULD PREVENT THE
STRATUS FROM MAKING IT INTO THE FOX VALLEY AND NORTHEAST
WISCONSIN...SO HAVE KEPT PARTLY CLOUDY WORDING THERE. NO REAL
CHANCE OF DECOUPLING TONIGHT...SO LOWS WILL BE MILD AND RANGE FROM
THE LOWER 20S NORTH TO AROUND 30 SOUTHEAST.
WEDNESDAY...STRATUS WILL LIKELY HANG AROUND FOR MUCH OF THE MORNING
OVER NORTHERN WISCONSIN THOUGH SOME EROSION IS LIKELY OVER CENTRAL
WISCONSIN WITH DAYTIME HEATING. THE COOLER AIRMASS WILL CONTINUE TO
MODERATE THROUGH THE AFTERNOON SO EXPECTING CLOUDS TO RETREAT TO THE
NORTH OR NORTHEAST THROUGH THE DAY. ALSO IN THE AFTERNOON...THE
NEXT SHORTWAVE TROUGH WILL MOVE INTO WESTERN WISCONSIN. MID-LEVELS
HAVE A DRY WEDGE SO NO REAL THREAT OF PRECIP. HIGHS WILL BE COOLER
THAN TODAY...AND WILL GO WITH MID TO UPPER 30S.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. SOUNDS LIKE A
BROKEN RECORD...BUT MORE MILD AND DRY WEATHER EXPECTED FOR THE
NEXT WEEK OR SO. THE SPLIT FLOW PATTER WILL CONTINUE WITH WEAK
SHORTWAVE TROUGHS MOVING BY TO THE NORTH THROUGH WITH LITTLE
MOISTURE WHILE MORE SIGNIFICANT SYSTEMS IN THE SOUTHERN STREAM STAY
TO OUR SOUTH. ANY PHASING THAT TAKES PLACE IS WELL TO OUR EAST.
THE BEST CHANCE OF ANY PRECIPITATION LOOKS TO BE SUNDAY OR SUNDAY
NIGHT AS SYSTEM IN THE SOUTHERN STREAM PASSES BY TO THE SOUTH. IT
MAY CLIP CENTRAL AND NORTHERN WISCONSIN WITH SOME LIGHT SNOW OR
RAIN BUT THAT/S ABOUT IT.
&&
.AVIATION...
LARGE AREA OF MVFR/IFR CIGS MOVING EAST THROUGH WESTERN WI AND MN
AT THIS TIME. TIMING BRINGS THESE CLOUDS INTO CENTRAL TAF SITES
EARLY EVENING. DOWNSLOPING...DUE TO WEST TO NORTHWEST WINDS
EXPECTED TO KEEP CIGS SCT TO BKN MVFR OVER FOX VALLEY AND NE
WISCONSIN (LATE EVENING THROUGH OVERNIGHT HOURS). STRATUS EXPECTED TO
MIX OUT MID DAY WED WITH DAYTIME HEATING.
TE
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
535 PM CST TUE JAN 31 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY
244 PM CST TUE JAN 31 2012
MAIN FORECAST CONCERNS ARE CLOUDS AND TEMPERATURES THROUGH FORECAST
PERIOD.
LATEST WATER VAPOR SATELLITE IMAGERY INDICATING WEAK SHORTWAVE
TROUGHS EMBEDDED IN WEST TO EAST ZONAL FLOW ACROSS THE CONTINENTAL
UNITED STATES. ONE SHORTWAVE TROUGH OVER THE UPPER MIDWEST IS
PRODUCING LOW STRATUS DECK OF CLOUDS ACROSS MUCH OF NORTHERN AND
CENTRAL MINNESOTA.
THE DETERMINISTIC 31.12Z NAM AND GFS INITIALIZED OVERALL UPPER LEVEL
PATTERN WELL PER LATEST UPPER AIR ANALYSIS. MAIN DIFFERENCE BETWEEN
THE DETERMINISTIC 31.12Z GFS AND NAM IS THE 31.12Z GFS SLIGHTLY
MORE ROBUST WITH WEAK SHORTWAVE TROUGH MOVING ACROSS THE UPPER GREAT
LAKES REGION WEDNESDAY NIGHT. OTHERWISE..THE DETERMINISTIC 31.12Z
GFS/NAM ARE IN DECENT AGREEMENT WITH SURFACE AND UPPER LEVEL FEATURES
THROUGH FORECAST PERIOD.
TONIGHT AND WEDNESDAY..LOW STRATUS DECK OF CLOUDS WILL CONTINUE TO
ADVANCE SOUTHEASTWARD INTO THE FORECAST AREA. BIG QUESTION WILL BE
HOW FAR SOUTH THE LOW STRATUS DECK ADVANCES. THE 31.12Z GFS AND
NAM DOES SHOW THE WESTERN EDGE OF STRATUS DECK TO ERODE AS THE LOW
CLOUDS ADVANCE INTO THE FORECAST AREA. FOR NOW HAVE INCREASED SKY
CONDITION ACROSS MUCH OF THE FORECAST AREA AFTER 00Z WEDNESDAY.
WITH REGION REMAINING UNDER CYCLONIC FLOW AND NEXT WEAK IMPULSE
TRACKS INTO THE UPPER GREAT LAKES REGION...LOW STRATUS DECK OF CLOUDS
IS EXPECTED TO REMAIN OVER THE NORTHEASTERN HALF OF THE FORECAST AREA
THROUGH WEDNESDAY NIGHT. THE 31.12Z GFS DOES INDICATE WEAK
LIFT/FORCING IN ASSOCIATION WITH THE WEAK IMPULSE AND PRODUCES SOME
LIGHT PRECIPITATION OVER NORTH CENTRAL WISCONSIN. AT THIS TIME...
WITH WEAK LIFT AND MINIMAL FORCING WILL CONTINUE WITH DRY
CONDITIONS ACROSS FORECAST AREA.
NEXT CONCERN IS BOTH THE 31.12Z GFS AND NAM CUTOFF UPPER LEVEL LOW
OVER THE SOUTHERN AND CENTRAL PLAINS AND LIFT UPPER LEVEL LOW INTO
CENTRAL KANSAS THURSDAY NIGHT INTO FRIDAY. BOTH THE 31.12Z GFS AND
NAM SHOW THE BEST ISENTROPIC LIFT AT 290K SURFACE TO BE SOUTH OF
FORECAST AREA. HAVE PUSHED PRECIPITATION CHANCES SOUTH AND
WEST OF FORECAST AREA THURSDAY NIGHT AND FRIDAY.
.LONG TERM...FRIDAY NIGHT TUESDAY
244 PM CST TUE JAN 31 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES FRIDAY NIGHT
INTO SUNDAY. THE DETERMINISTIC 31.12Z GFS/GEM/ECMWF ARE IN DECENT
AGREEMENT IN CUTTING OFF UPPER LEVEL LOW OVER THE SOUTHERN AND
CENTRAL PLAINS FRIDAY NIGHT AND SATURDAY. HOWEVER...THE DETERMINISTIC
MODELS ARE IN DISAGREEMENT IN LIFTING UPPER LEVEL LOW INTO THE UPPER
MIDWEST AND GREAT LAKES REGION AFTER 18Z SATURDAY. CONFIDENCE IN
PRECIPITATION CHANCES ARE LOW FRIDAY NIGHT INTO SATURDAY...DUE TO
HIGH VARIABILITY IN LIFTING/MOVING CUTOFF LOW INTO THE UPPER
MIDWEST. TEMPERATURES THROUGH FORECAST PERIOD WILL REMAIN ABOVE
NORMAL...AS UPPER LEVEL CUTOFF LOW ADVECTS WARMER AIR NORTHWARD INTO
THE UPPER MIDWEST.
&&
.AVIATION...TONIGHT AND WEDNESDAY
535 PM CST TUE JAN 31 2012
STRATUS IN THE WAKE OF A COLD FRONT WAS PUSHING INTO SOUTHEAST
MINNESOTA EARLY THIS EVENING. CEILINGS HAVE GENERALLY BEEN IN THE
010KFT-020KFT FOOT RANGE...WITH SOME EMBEDDED IFR CEILINGS. BOTH
SATELLITE TRENDS AND 31.21Z RUC BUFKIT SOUNDINGS SHOWS THIS
STRATUS TO AFFECT BOTH TAF SITES BY EARLY EVENING AND THEN
CONTINUE INTO WEDNESDAY AFTERNOON. WITH AN INFLUX OF MOISTURE FROM
THE MELTING SNOW WILL LIKELY SEE CEILINGS CONTINUE TO LOWER WITH
IFR CONDITIONS AT KRST AND LOW MVFR CEILINGS AT KLSE...BUT WILL
HAVE TO WATCH KLSE FOR THE POSSIBILITY OF IFR CONDITIONS. ENOUGH
MIXING IN THE LOWER LAYERS OF THE ATMOSPHERE WILL PRECLUDE DENSE
FOG...BUT SOME MVFR VISIBILITIES OF 3-5SM ARE LIKELY. CONFIDENCE
NOT HIGH THAT STRATUS WILL BREAK WEDNESDAY AFTERNOON...BUT BUFKIT
SOUNDINGS SHOWING INVERSION BREAKING IN THE AFTERNOON. DID
SCATTERED THE STRATUS OUT BETWEEN 19Z-21Z AT THE TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
244 PM CST TUE JAN 31 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
322 PM CST MON JAN 30 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY
321 PM CST MON JAN 30 2012
MAIN FORECAST CONCERNS ARE ON PATCHY FOG/LOW STRATUS POTENTIAL
TONIGHT INTO TUESDAY MORNING. FOCUS THEN TURNS TO CLOUD COVER AND
TEMPERATURES TUESDAY AFTERNOON THROUGH THURSDAY
CURRENT SURFACE OBSERVATIONS PLACE A WARM FRONT EXTENDING FROM NORTH
CENTRAL NORTH DAKOTA....SOUTHEAST TO JUST NORTH OF MINNEAPOLIS...TO
ALONG THE INTERSTATE 94 CORRIDOR ACROSS CENTRAL WISCONSIN. A PLUME
OF GULF MOISTURE WAS NOTED OVER NORTHERN MISSOURI/SOUTHEAST
IOWA...MOVING NORTHEAST. DEW POINTS WITHIN THIS PLUME RANGED FROM
THE MID TO UPPER 30S.
THE WARM FRONT WILL LIFT SLIGHTLY NORTH TONIGHT AS SOUTHERLY FLOW
CONTINUES ACROSS THE FORECAST AREA. WITH TEMPERATURES WARMING ABOVE
FREEZING THIS AFTERNOON ALLOWING SOME MELTING OF THE SNOW PACK...AND
INTRODUCING MORE MOISTURE INTO THE BOUNDARY LAYER...SHOULD SEE SOME
PATCHY FOG DEVELOPMENT TONIGHT. THERE IS UNCERTAINTY REGARDING THE
DEVELOPMENT OF A STRATUS DECK OVER THE SNOW PACK TONIGHT. THE SOUTH
TO SOUTHWEST WINDS WOULD FAVOR TAKING THE HIGHER DEW POINT AIR JUST
EAST OF THE FORECAST AREA. HOWEVER...MODELS ARE INDICATING THE
GRADIENT WILL SLACKEN AND ALLOW WINDS TO BACK TO THE
SOUTH...ADVECTING IN THE HIGHER DEW POINT AIR. THERE ARE CONCERNS
ON WHETHER OR NOT THE STRATUS OR FOG WILL DEVELOP WITH WINDS JUST
ABOVE THE SURFACE OUT OF THE SOUTHWEST...WITH VERY DRY AIR IN
PLACE ALOFT. THE NAM/RUC ARE SHOWING THE DEVELOPMENT OF LOW
STRATUS AND FOG ACROSS MUCH OF THE FORECAST AREA TONIGHT. FEEL
THESE SOLUTIONS ARE A BIT OVERDONE WITH THE DRY AIR ACROSS WESTERN
NEBRASKA INTO WESTERN IOWA...ADVECTING NORTHEAST. THINKING IF
STRATUS/FOG DOES DEVELOP...IT WOULD OCCUR MAINLY ACROSS NORTHEAST
IOWA...AND ALONG/EAST OF THE MISSISSIPPI RIVER. HAVE DECIDED TO
INCLUDE PATCHY FOG IN THE FORECAST LATE TONIGHT THROUGH EARLY
TUESDAY MORNING MAINLY SOUTH OF INTERSTATE 90. GIVEN THE MIXING
AND DRY AIR ALOFT...FOG LOOKS TO BE MUCH MORE FAVORABLE THAN
STRATUS. ALSO HAVE INCREASE CLOUD COVER SLIGHTLY MAINLY ALONG AND
SOUTHEAST OF A LINE FROM CHARLES CITY IA TO MARSHFIELD WI. LOOK
FOR LOW TEMPERATURES TO RANGE FROM THE UPPER 20S ACROSS NORTH
CENTRAL WISCONSIN TO THE LOWER 30S ACROSS NORTHEAST IOWA.
A COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION LATE TUESDAY
AFTERNOON BRINGING A BRIEF SHOT OF SLIGHTLY COOLER AIR TO THE
AREA. BEFORE THE FRONT MOVES IN...LOOK FOR HIGH TEMPERATURES TO
CLIMB INTO THE UPPER 30S TO LOWER 40S. STRATUS IS EXPECTED TO MOVE
INTO THE AREA BEHIND THE FRONT DURING THE LATE AFTERNOON INTO THE
EARLY EVENING HOURS...LEADING TO MOSTLY CLOUDY SKIES. WEAK HIGH
PRESSURE WILL BUILD INTO THE REGION TUESDAY NIGHT INTO WEDNESDAY
PROVIDING DRY AND QUIET WEATHER. PLAN ON HIGHS ON WEDNESDAY
RANGING FROM THE MID 30S ACROSS NORTH CENTRAL WISCONSIN TO AROUND
40 ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
30.12 MODELS IN AGREEMENT ON THURSDAY...SHOWING A TROUGH DIGGING
INTO THE CENTRAL ROCKIES WITH RIDGING ALOFT MOVING ACROSS THE
FORECAST AREA. MODEL SOLUTIONS START TO DIVERGE GREATLY THURSDAY
NIGHT. THE OPERATIONAL GFS/GEM DEVELOP A POTENT LOW PRESSURE SYSTEM
ACROSS THE CENTRAL PLAINS...AND SUGGEST IT WILL MOVE NORTHEAST
TOWARDS THE FORECAST AREA INTO FRIDAY. ON THE OTHER HAND...THE GFS
ENSEMBLE MEMBERS AND ECMWF TAKE THIS FEATURE WELL SOUTH OF THE
REGION. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW MODELS RUNS.
PLAN ON HIGHS ON THURSDAY RANGING FROM THE MID 30S ACROSS NORTH
CENTRAL WISCONSIN TO THE LOWER 40S ACROSS NORTHEAST IOWA. LOOK FOR
LOWS TO FALL INTO THE 20S.
.LONG TERM...FRIDAY THROUGH MONDAY
321 PM CST MON JAN 30 2012
MAIN FORECAST CHALLENGE THIS PERIOD IS EVOLUTION OF THE 500MB TROUGH
ACROSS THE ROCKIES...AND POTENTIAL DEVELOPMENT OF SURFACE LOW LIFTING
ACROSS THE CENTRAL PLAINS FRIDAY THROUGH SUNDAY...WITH IMPACT ON
TEMPERATURES AND PRECIPITATION CHANCES.
LONG RANGE GUIDANCE COMING INTO SLIGHTLY BETTER AGREEMENT THAT A 500MB
TROUGH SWINGS ACROSS ROCKIES LATE THURSDAY NIGHT...BECOMING CUT OFF
FRIDAY 12Z ACROSS SOUTHERN COLORADO / NORTHERN NEW MEXICO. AS THIS
ENERGY EJECTS INTO THE CENTRAL PLAINS...THE 30.12Z GFS / GEM-NH
DEPICTS A SURFACE LOW DEVELOPING...LIFTING NORTHEAST TOWARDS THE
AREA. MEANWHILE...30.12Z ECMWF IS VERY SIMILAR TO ITS PREVIOUS
RUN...AND DIGS THE 500MB TROUGH A BIT FURTHER SOUTH. THIS WOULD
ALLOW THE SURFACE LOW TO BE PICKED UP IN THE SOUTHERN
STREAM...SHUNTING THE LOW ACROSS THE OHIO RIVER VALLEY. THE GFS /
GEM-NH SCENARIO IS CONSIDERED THE DEEPER...SLOWER SOLUTION AND WOULD
HAVE A LARGE PRECIPITATION SHIELD ACROSS MUCH OF THE NORTHERN PLAINS
INTO PARTS OF THE UPPER MIDWEST. THE FORECAST AREA WOULD PRIMARILY
BE ON THE WARM SIDE...WITH A SNOW QUICKLY CHANGING TO
RAIN/SNOW...EVEN ALL RAIN...STARTING FRIDAY NIGHT THROUGH SUNDAY
MORNING. THE 30.12 ECMWF SOLUTION WOULD KEEP THE FORECAST AREA DRY
THROUGH THE WEEKEND. THE SOMEWHAT MORE CONSISTENT ECMWF HAS ITS
MERIT...BUT THE LATEST GFS / GEM-NH SOLUTIONS NEED TO BE KEPT IN
MIND.
AT THIS TIME GIVEN THE SPREAD BETWEEN THE OPERATIONAL MODELS AND LOW
RUN-TO-RUN CONSISTENCY...WILL SIDE WITH MODEL CONSENSUS BLEND AND
INCLUDE SLIGHT CHANCES OF PRECIPITATION THIS WEEKEND.
&&
.AVIATION...THROUGH 18Z TUESDAY
321 PM CST MON JAN 30 2012
CURRENT SURFACE MAP HAS LOW PRESSURE OVER ND WITH A WARM FRONT
EXTENDING SOUTHEAST ACROSS CENTRAL MN INTO CENTRAL WI. SOUTHWEST
FLOW SOUTH OF THE WARM FRONT HAS WARMED TEMPERATURES UP TODAY
SIGNIFICANTLY...AND WAS PRODUCING SNOW MELT ACROSS SOUTHERN
MN/NORTHEAST IA/SOUTHWEST WI. HOWEVER...DEW POINT ANALYSIS SHOWS
THAT DRIER SOUTHWEST FLOW FROM THE CENTRAL PLAINS WAS OFF-SETTING
LOWER BOUNDARY LAYER MOISTURE LOADING FROM THE SNOW MELT. 18Z NAM
AND 20Z RUC MODELS/BUFKIT SOUNDINGS SHOW VERY SHALLOW LOW LAYER OF
MOISTURE TONIGHT INTO TUESDAY MORNING. 18Z TAF ISSUANCE ORIGINALLY
HAD IFR CIG IN STRATUS IN THE KLSE/KRST TAFS AFTER TUE 12Z...BUT
THINKING NOW THAT DEEPER BOUNDARY LAYER MOISTURE FOR STRATUS WILL
REMAIN SOUTHEAST OF THE SITES. AMENDED 18Z TAFS TO GO WITH THIS
TREND AND CARRIED 5-6SM BR AFTER 03Z TONIGHT...LASTING INTO TUESDAY
MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
321 PM CST MON JAN 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....ZT
AVIATION.....DAS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
245 PM CST MON JAN 30 2012
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LIGHT SNOW
ASSOCIATED WITH A MID-LEVEL FGEN BAND ALONG AN ELEVATED WARM FRONT
HAS RAPIDLY PUSHED TO THE EAST EARLY THIS AFTERNOON LEAVING
WIDESPREAD MID AND HIGH CLOUDS OVERHEAD. THE SURFACE WARM FRONT IS
STILL LAGGING BEHIND FROM MINNEAPOLIS TO CHICAGO...BUT SE WINDS
NORTH OF THE BOUNDARY HAS BROUGHT WARMER MARINE AIR INTO
NORTHEAST WISCONSIN WHERE TEMPS HAVE REACHED INTO THE MIDDLE 30S.
DESPITE THE WARM ADVECTION...NO SIGN OF ANY STRATUS/DRIZZLE/FOG
DEVELOPMENT UPSTREAM SO FAR...BUT THE ABOVE 30F DEWPOINTS ARE NOW
REACHING INTO EASTERN IOWA AND NORTHERN ILLINOIS. AS WARM ADVECTION
CONTINUES UNABATED AHEAD OF LOW PRESSURE DEVELOPING OVER THE
NORTHERN ROCKIES...LOW STRATUS AND FOG POTENTIAL ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...A SHORTWAVE TROUGH WILL MOVE ACROSS THE DAKOTAS AND PUSH
SURFACE LOW PRESSURE OVER THE NORTHERN MISSISSIPPI VALLEY. AHEAD OF
THE LOW...H850 WARM FRONT WILL LIFT ACROSS THE U.P. INTO
LAKE SUPERIOR. THE THREAT OF PRECIP WILL BE LOCATED ALONG THIS
BOUNDARY AND NORTH OF THE FORECAST AREA...SO HAVE REMOVED POPS FOR
TONIGHT. WILL STILL HAVE PLENTY OF MID AND UPPER MOISTURE AROUND
CARRIED IN BY THE JET STREAM TO MAKE FOR A PARTLY TO MOSTLY CLOUDY
NIGHT. THE BIGGEST FORECAST CHALLENGE TONIGHT WILL BE THE
POSSIBILITY OF FOG OR LOW STRATUS DEVELOPMENT LATE. SSW WILL CARRY
DEWPOINTS IN THE UPPER 20S TO LOWER 30S OVER THE MID-MISSISSIPPI
VALLEY INTO THE REGION TONIGHT. THE NAM IN PARTICULAR IS BULLISH ON
CREATING LOW STRATUS OR FOG BUT COULD BE ONE OF THOSE SCENARIOS
WHERE TEMPS JUST ABOVE THE SURFACE RISE COINCIDENT WITH DEW POINTS
WHICH WOULD CREATE SOME LOWER VSBYS AND FROST DEPOSITS BUT WITHOUT
ANY FOG OR STRATUS. NOT SEEING MUCH POTENTIAL FOR DRIZZLE AS THE
MOISTURE DOESNT APPEAR DEEP ENOUGH. SO WILL PUNT IT OFF TO THE
EVENING CREW UNTIL CAN SEE THE WHITES OF ITS EYES. WITH THE WARM
ADVECTION...LOW TEMPS WILL NOT FALL MUCH...FROM THE MID 20S NORTH TO
LOW 30S SE.
TUESDAY...LOW PRESSURE WILL CONTINUE TO TRACK EAST ALONG THE WARM
FRONT OVER THE U.P. SOUTH OF THE LOW TRACK...GULF MOISTURE WILL
SURGE NORTHEAST BUT LOOKS TO BYPASS THE REGION INTO LOWER MICHIGAN.
AS A RESULT...OUR AIR WILL ARRIVE FROM THE DRIER SOUTHERN GREAT
PLAINS WHICH WILL KEEP THE MID-LEVELS DRY DESPITE A WEAK PACIFIC
COOL FRONT PASSING ACROSS THE AREA IN THE AFTERNOON. AFTER SOME
MORNING MIST OR LOW STRATUS...SHOULD SEE PARTLY TO MOSTLY CLOUDY
SKIES ACROSS THE AREA IN THE AFTERNOON. HIGHS WILL BE WARM AFTER A
MILD START TO THE DAY...WITH HIGHS RANGING FROM THE UPPER 30S NORTH
TO MIDDLE 40S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. MILD WEATHER WILL
CONTINUE THROUGH THE REMAINDER OF THE WEEK AND INTO EARLY NEXT
WEEK. CLOUD COVER AND TEMPERATURES ARE THE PRIMARY CHALLENGE
THROUGH SATURDAY AS THERE IS LITTLE CHANCE OF ANY PRECIPITATION.
THE VERY MILD TEMPERATURES AND MELTING SNOW WILL LIKELY PRODUCE
LOW CLOUDS AND FOG AT SOME POINT...ESPECIALLY IN NORTHERN
WISCONSIN WHERE SNOW COVER IS A FOOT OR SO. BUT NOT CERTAIN ENOUGH
ABOUT WHEN THIS MIGHT OCCUR SO DID NOT MENTION ANY FOG IN THE
FORECAST. WE DO EXPECT SOME BY LATER IN THE WEEK.
THE MODELS DO BRING SOME SOUTHERN STREAM JET ENERGY FROM FOUR
CORNERS AREA FRIDAY INTO THE CENTRAL PLAINS SATURDAY AND SUNDAY.
THE EVOLUTION OF THE SYSTEM IS DIFFERENT FROM MODEL TO MODEL AND
RUN TO RUN SO DO NOT HAVE A LOT OF CONFIDENCE AT THIS POINT. THE
GFS SOLUTIONS COULD PRODUCE CONSIDERABLE SNOW OVER WESTERN
WISCONSIN IF IT WOULD VERIFY. THERE IS SOME DECENT AGREEMENT NOW
THAT AN UPPER RIDGE WILL FORM OVER THE WESTERN PART OF NORTH
AMERICA WITH A TROUGH EAST OF ROCKIES. THE MODELS HAVE ADVERTISED
THIS A COUPLE OF TIMES THIS WINTER BUT IT HAS NOT MATERIALIZED.
&&
.AVIATION...WITH THE SNOW DEPARTING FAR NE WISCONSIN BY EARLY THIS
AFTERNOON...SOUTHWEST FLOW WILL DEVELOP LATER TODAY AND CONTINUE THROUGH
THE REST OF THE TAF PERIOD. THOUGH THERE WILL BE PLENTY OF MID AND
HIGH CLOUDS OVERHEAD...MODELS INSIST ON TRANSPORTING LOW LEVEL
MOISTURE FROM THE MID-MISSISSIPPI VALLEY INTO THE REGION LATE
TONIGHT INTO TOMORROW MORNING. DEWPOINTS IN THE UPPER 20S TO LOWER
30S EXIST THERE CURRENTLY AND NOT INCONCEIVABLE THAT LOW STRATUS MAY
DEVELOP LATE. UNCERTAINTY IS FAIRLY HIGH HERE...AS THERE IS NO
STRATUS UPSTREAM. HAVE SIDED OPTIMISTICALLY...AND ADDED MVFR VSBYS
IN MIST IN THE TAFS LATE TONIGHT INTO TOMORROW MORNING. LATER
SHIFTS WILL HAVE TO REFINE PENDING THE DEVELOPMENT OF STRATUS.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
248 AM CST MON JAN 30 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
IMPRESSIVE WARM AIR ADVECTION OCCURRING THIS MORNING...BUT THE
ATMOSPHERE IS REALLY STRUGGLING TO SATURATE INTO THE LOWER LEVELS.
THE BULK OF ANY MEASURABLE SNOW SHOULD REMAIN ACROSS THE NORTHERN
1/3 OF THE CWA THIS MORNING. THE HRRR DOES SHOW THE POTENTIAL FOR A
VERY NARROW BAND OF SNOW DEVELOPING BETWEEN 10-13Z THAT STRETCHES
SOUTHEAST INTO JEFFERSON/WAUKESHA COUNTIES. THIS IS WITHIN A NARROW
REGION OF DECENT ISENTROPIC LIFT. CERTAINLY CAN/T RULE IT OUT. AT
WORST WE ARE LOOKING AT PROBABLY 1/2 INCH OR LESS OF SNOW ACCUM.
I/M NOT SEEING A GOOD REASON TO HANG ONTO ANY FREEZING TYPE PRECIP
LATER THIS MORNING ACROSS THE NORTHEAST. IT APPEARS THE PRECIP WILL
BE GONE BEFORE WE GET AN ELEVATED WARM LAYER COMPLICATING THINGS. AS
THE WARM FRONT PUSHES THROUGH AROUND MID DAY...SHOULD SEE SOME
CLEARING/SUNSHINE IN ITS WAKE. SOUNDINGS SUGGEST THE BULK OF THE
WARMING WILL STAY ABOVE THE BOUNDARY LAYER...ESPECIALLY WITH FAIRLY
LOW SFC DWPNTS INITIALLY...SO DON/T WANT TO GO TOO CRAZY WITH HIGHS
TODAY. SUSPECT ANY 40S WILL BE LIMITED TO THE FAR SOUTHERN CWA.
TEMPS WON/T MOVE VERY MUCH TONIGHT...BUT DEW POINTS WILL BE ON THE
RISE. TEMP/DWPNT DEPRESSION REALLY NARROWS ACROSS THE SOUTHEAST HALF
OF THE CWA AS DWPNTS CLIMB TO AT OR ABOVE FREEZING. THIS COULD ALSO
LEAD TO SOME STRATUS DEVELOPMENT. THINK ANY DRIZZLE/LGT RAIN WILL
HAVE TO WAIT UNTIL DEEPER SATURATION OCCURS ON TUESDAY.
TUESDAY - CONFIDENCE...MEDIUM
INFLUENCE OF APPROACHING NORTHERN PLAINS STAYS LARGELY NORTH OF CWA
THROUGH THE DAY...WITH SOME PVA WORKING IN DURING THE EVENING. 850
JET SHOVES BRUNT OF MOISTURE NORTHEAST INTO THE OHIO VALLEY. BOTH
GFS AND NAM BUFKIT SHOW A STRONG INVERSION...WITH NO MOISTURE ABOVE
900 MILLIBARS. POTENTIAL CERTAINLY THERE FOR A MOIST AND MILD DAY
WITH LOW STRATUS AND LIGHT FOG. SHOULD BE ENOUGH WIND IN THE LOWEST
LEVELS TO KEEP THE SOUTHWEST WIND GOING. HOPEFULLY KEEPING THINGS
STIRRED UP ENOUGH TO PREVENT WIDESPREAD DENSE FOG FORMATION. NAM AND
GFS BOTH SHOW VERY LIGHT QPF WITH THE 850 FRONT SO WILL SIDE WITH
THE SLIGHTISH ALLBLEND POPS TO ACCOUNT FOR THIS. 00Z ECMWF IMPLIES
THAT BETTER PRECIP CHANCE COMES IN THE AFTERNOON HOURS. WILL GO
WITH SMALL POPS IN THE EAST FOR LIGHT RAIN AND HAVE PATCHY DRIZZLE
IN THE WEST AS LOW LEVEL MOISTURE TO AVOID MIXING MEASURABLE AND
NONMEASURABLE PTYPES. MID LEVEL DRY AIR BECOMES VERY PRONOUNCED
ABOVE INVERSION.
WEDNESDAY AND THURSDAY - CONFIDENCE...MEDIUM
LOOKS QUIET WITH WEAK COOL AIR ADVECTION. NO FORCING OF NOTE AND
COLUMN LOOKS PARCHED. TEMPS REMAIN UNSEASONABLY MILD. NOT MUCH FLOW.
WITH CONTINUED SNOWMELT AND SUBSEQUENT MOISTENING OF THE BOUNDARY
LAYER...WILL HAVE TO WATCH FOR STRATUS/FOG POTENTIAL.
FRIDAY THROUGH SUNDAY - CONFIDENCE...LOW TO MEDIUM
MODELS SHOWING DIFFERENT SOLUTIONS WITH RESPECT TO THE UPPER LOW
PLODDING THROUGH MID MISSISSIPPI VALLEY INTO THE OHIO VALLEY.
SUGGESTION IS THAT WI WILL BE MORE UNDER THE INFLUENCE OF THE UPPER
FLOW OUT OF CANADA...WHICH SETS UP A CONFLUENT ZONE ACROSS WI. AT
THIS POINT GEMNH AND GFS MOST CLOSELY RESEMBLE EACH OTHER WHILE THE
ECMWF HAS A MUCH SLOWER...FURTHER WEST AND NORTH POSITIONING OF
UPPER LOW. NO INVASION OF ANYTHING RESEMBLING AN ARCTIC AIRMASS.
ONSHORE FLOW FRIDAY AND SATURDAY HOWEVER AT THIS POINT THE DELTA-T
VALUES DO NOT LOOK SUPPORTIVE OF PRECIPITATION DEVELOPMENT. MILD
EARLY FEBRUARY TEMPS CONTINUE.
&&
.AVIATION/12Z TAFS/...LOOKS LIKE VFR CONDITIONS WILL RULE THROUGH MOST
OF THE TAF FCST PERIOD. THE WARM AIR ADVECTION PRECIP SHOULD
MOSTLY STAY NORTH OF A MILWAUKEE TO MADISON LINE...BUT CAN/T RULE
OUT A BRIEF PERIOD OF LIGHT SNOW OR FLURRIES BEFORE ABOUT 12Z AT
MADISON AND 15Z AT MILWAUKEE. LITTLE OR NO ACCUMULATION IS
EXPECTED. WARMER AND MORE MOIST AIR ARRIVING TONIGHT COULD LEAD TO
STATUS DEVELOPMENT... ESPECIALLY FOR MILWAUKEE/WAUKESHA AND
KENOSHA. CONFIDENCE ON THIS OCCURRING BEFORE 12Z TUE IS RATHER
LOW...SO MAY LEAVE THIS OUT OF THE TAFS FOR NOW.
&&
.MARINE...BRISK SOUTHEAST WINDS AHEAD OF THE APPROACHING WARM FRONT WILL
LIKELY LEAD TO SMALL CRAFT ADVISORY CONDITIONS TODAY. WINDS ARE A
BIT MARGINAL...BUT THE TRAJECTORY IS FAVORABLE FOR RAPID WAVE
DEVELOPMENT EXCEEDING 4 FEET. WINDS AND WAVES DIMINISH BY EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
TUESDAY THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1137 PM CST SUN JAN 29 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SYNOPSIS...MORE MILD WEATHER.
MODEST LARGE SCALE TROF OVER THE ERN CONUS WL SHIFT NEWD THE NEXT
COUPLE DAYS...PUTTING US BACK INTO WHAT HAS BECOME THE PATTERN OF
THE WINTER...A BROAD SOMEWHAT SPLIT ZONAL REGIME. HEIGHTS OVER WRN
CANADA WL GRADUALLY RISE LATER THIS WK. THAT WL EVENTUALLY FAVOR A
RETURN TO AN ERN TROF. MODELS OFFERED VARYING IDEAS ON HOW
SHARP/STG THE WRN RIDGE WL BECOME...AND THAT WILL MODULATE THE
STRENGTH OF THE DOWNSTREAM TROF. PERSISTENCE WOULD FAVOR THE
LESS AMPLIFIED OF THE GUIDANCE SOLUTIONS.
AFTER A RELATIVELY COLD NGT TNGT...TEMPS WL WARM TO SIGNIFICANTLY
ABV NORMAL LEVELS AGAIN FOR THE EARLY PART OF THE FCST PERIOD.
THEY WL DROP BACK CLOSER TO NORMAL BY NEXT WEEKEND...BUT UNLESS
ERN TROF GETS A LOT DEEPER THAN NOW EXPECTED...IT/S HARD TO SEE
THEM GOING BLO NORMAL. THE FCST AREA WL PROBABLY HAVE A COUPLE LGT
PCPN EVENTS...WITH AMNTS PROBABLY ENDING UP BLO NORMAL FOR THE
PERIOD AS A WHOLE.
&&
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE WORKING EASTWARD ACROSS THE NORTHERN MISSISSIPPI VALLEY
EARLY THIS AFTERNOON. LOW STRATO-CU CLOUD DECK IS SLOWLY LIFTING
OFF TO THE NORTHEAST OVER NORTHEAST WISCONSIN...WHILE THE REST OF
THE REGION REMAINS SUNNY. LOOKING UPSTREAM...PRETTY EXPANSIVE CLOUD
SHIELD IS PRESSING EAST ACROSS THE DAKOTAS...JUST AHEAD OF A
DEVELOPING SURFACE WARM FRONT. AS THE WARM FRONT MOVES EAST ACROSS
THE REGION LATE TONIGHT INTO MONDAY...PRECIP TIMING AND AMOUNTS ARE
THE MAIN FORECAST CONCERNS.
TONIGHT...THE HIGH PRESSURE RIDGE AXIS WILL SLIDE ACROSS THE STATE
DURING THE EVENING HOURS. SHOULD SEE A PERIOD OF CLEAR SKIES AND
LIGHT WINDS THAT WOULD ALLOW TEMPS TO TAKE A TUMBLE. WENT ON THE
COLD SIDE OF GUIDANCE FOR THIS REASON...AS IT USUALLY DOESNT TAKE
MUCH TIME FOR TEMPS TO FALL 20 DEGREES...ESPECIALLY OVER
NORTH-CENTRAL WISCONSIN. THEREAFTER...A 850MB WARM FRONT OVER THE
NORTHERN PLAINS WILL SHIFT EAST INTO SOUTHWEST WISCONSIN AFTER
MIDNIGHT. MODELS HAVE A VARIETY OF ARRIVAL TIMINGS OF THE LIGHT
SNOW AS IT SPREADS SE ALONG THE FRONT INTO CENTRAL WISCONSIN LATE.
DONT REALLY HAVE A GOOD FEEL IF THE FASTER PACE OF THE GFS COMPARED
TO THE NAM IS LIKELY TO BE CORRECT. SO WENT MIDDLE OF THE ROAD FOR
POPS/QPF WHICH PLACES LIKELY POPS OVER NORTH-CENTRAL AND CENTRAL
WISCONSIN. PERHAPS CENTRAL WISCONSIN COULD SEE A QUICK HALF INCH OF
FLUFF BY 12Z. TEMPS SHOULD REBOUND ONCE THE CLOUDS ROLL IN...SO
MIDNIGHT LOWS WILL CREEP BACK UP THROUGH THE OVERNIGHT.
MONDAY...THE WARM FRONT WILL CONTINUE TO MOVE EAST ACROSS THE REGION
ON MONDAY. WILL SEE THE MOST WIDESPREAD SNOW DURING THE MORNING
HOURS WHEN A DECENT BAND OF MID-LEVEL FGEN MOVES OVERHEAD. MOST
PLACES WILL SEE 1-2 INCHES OF SNOW. THE PRIMARY UNCERTAINTY OF THE
EVENT WILL BE THE PTYPE ON THE BACK EDGE OF THE PRECIPITATION SHIELD
WHEN MOISTURE FALLS BELOW -10C...WHICH INCREASES THE PROBABILITY OF
THE ABSENCE OF ICE CRYSTALS IN THE CLOUD. WITH CLOUD COVER AND
PRECIP HOLDING BACK SURFACE TEMPS...THINK THERE COULD BE A RIBBON OF
FREEZING DRIZZLE...MAINLY OVER CENTRAL AND EAST-CENTRAL WISCONSIN ON
THE BACK EDGE. BUT DONT THINK IT WILL POSE A HAZARD AS THE FRONT IS
RELATIVELY FAST MOVING AND SHARP...AS OPPOSED TO A LONG DURATION
OVER-RUNNING EVENT. TEMPS MAY REACH ABOVE FREEZING OVER CENTRAL AND
E-C WISCONSIN AS THE PRECIP ENDS AND CLOUDS ERODE HERE FIRST LATE IN
THE AFTERNOON.
.LONG TERM...MON NGT THROUGH NEXT SUN. THE MESO WRF RUNS FM NCEP
SUGGESTED SOME LGT PCPN COULD STILL LINGER IN THE THE NE EARLY MON
NGT...BUT WITH LITTLE SUPPORT FM ANY OF THE OTHER MODELS STUCK
WITH A DRY FCST. MILD SLY FLOW WL PREVENT MUCH DROP IN TEMPS...SO
BUILT 3 HOURLY TEMP GRIDS FROM A ROBUST BLEND OF GUID PRODUCTS AND
THEN GENERATED MIN GRID FROM THAT.
TUE WAS THE MOST CHALLENGING DAY OF THE FCST PERIOD. WK CYCLONE WL
BE TRACKING EWD ALONG THE U.S. CANADIAN BORDER TOWARD LAKE
SUPERIOR...WITH FCST AREA BASICALLY IN THE WARM SECTOR. OVERALL...
FORCING FOR PCPN WEAK. BUT SOME QG FORCING FM UPR SHRTWV COULD
GENERATE SOME LGT PCPN ACRS THE NW PART OF THE FCST AREA DURING
THE AFTN. CONTD SLGT CHC OF RA/SN TO ACCOUNT FOR THAT. MAIN
QUESTION HOWEVER IS THE CLDS AND THEIR IMPACT ON TEMPS. IT COULD
BE A VERY MILD DAY IF WE CAN ESCAPE HAVING ST FORM ACRS THE AREA.
IF THE ST DOES FORM...IT WL LIMIT TEMPS AND DAMP SLY FLOW WL
PROBABLY MAKE IT SEEM COLDER THAN IT IS. STUCK WITH MAX TEMPS FM
PREV FCST WHICH WERE GENERALLY BLO WHAT BEST PERFORMING GUID WOULD
SUGGEST FOR HIGH TEMPS. INCOMING DWPTS IN THE LOWER TO MIDDLE 30S
MARGINAL FOR ST FORMATION...AND DIDN/T WANT TO TAKE TEMPS BEYOND
WHAT WE HAD GOING WITHOUT HAVING MORE CONFIDENCE THAT WE WOULDN/T
GET STUCK WITH LOW CLDS.
QUIET WX THEN EXPECTED TUE NGT AND WED AS THE CYCLONE PASSES OFF
TO THE E OF THE RGN.
&&
.AVIATION...VFR THROUGH 09Z TONIGHT AS HIGH CLOUDS INCREASE FROM
THE WEST. CIGS AND VSBYS WILL FALL QUICKLY BETWEEN 09Z AND 12Z
MONDAY AS AN AREA OF SNOW FORMS NORTH OF A WARM FRONT. THE SNOW
WILL TAPER OFF BY EARLY AFTERNOON. THERE IS A SMALL CHANCE OF
FREEZING DRIZZLE MONDAY AFTERNOON BUT DID NOT INCLUDE IN TAFS
RIGHT NOW AS CHANCE IS SMALL. THE SNOW SHOULD BE LIGHT ENOUGH TO
SWEEP OFF RUNWAYS AT MOST AIRPORTS AS ACCUMULATIONS SHOULD BE 1
TO 2 INCHES AT MOST.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
444 AM EST WED FEB 1 2012
.SYNOPSIS...
LOW PRESSURE MOVING EASTWARD THROUGH SOUTHERN CANADA AND INTO
NORTHERN NEW ENGLAND TODAY WILL BRING A COLD FRONT THROUGH OUR AREA
THIS AFTERNOON...WHICH WILL STALL TO OUR SOUTH TONIGHT. ANOTHER WAVE
OF LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS
JUST SOUTH OF OUR AREA THURSDAY MORNING. HIGH PRESSURE WILL THEN
RETURN FOR LATER THURSDAY INTO SATURDAY. ANOTHER AREA OF LOW
PRESSURE MIGHT RIDE JUST SOUTH OF OUR REGION LATER SATURDAY NIGHT
INTO SUNDAY...OTHERWISE HIGH PRESSURE IS EXPECTED TO BUILD INTO
MONDAY. ANOTHER FRONT MAY AFFECT OUR REGION MONDAY NIGHT INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN FORECAST PROBLEM FOR TODAY WILL BE THE TIMING AND EXTENT OF
SHOWERS...MAINLY THIS MORNING.
THE AREA OF SHOWERS HAS EXPANDED AND SPED UP A BIT...AS THE LOW
LEVEL JET GETS CLOSER. PRECIPITABLE WATER VALUES HAVE INCREASED TO
NEAR 0.80 INCHES...AND THE AREA OF SHOWERS SITS RIGHT IN THE
RIDGING OF PRECIPITABLE WATER AND LOW LEVEL THETA E. THE FORECAST
WAS UPDATED TO EXPAND THE COVERAGE AND SPEED UP THE MENTION OF THE
TIMING OF THE BEST CHANCE OF SHOWERS.
SHOWERS HAVE ALSO INCREASED ACROSS SOUTHERN AREAS...AND THE
FORECAST WAS UPDATED FOR THIS AS WELL. SOME OF THE SHOWERS ACROSS
THE SOUTH HAVE CONVECTIVE LOOKS TO THEM...BUT THE AIRMASS IS
FAIRLY STABLE...AS DEW POINTS ARE STILL IN THE 30S.
THERE IS A SMALL CONCERN FOR GUSTY WINDS WITH THE PASSAGE OF THE
SHOWERS THIS MORNING. A PEAK GUST OF 39 KNOTS WAS NOTED AT KJST
BEFORE 0700 UTC...IN THE VICINITY OF SOME OF THE SHOWERS. THIS
APPEARS TO BE CLOSE TO THE NOSE OF THE 45 KNOT LOW LEVEL...AND THE
CONVECTIVE NATURE OF THE SHOWERS COULD BE HELPING TO MIX MOMENTUM
DOWN. FOR NOW...WILL CONTINUE TO MONITOR THE TRENDS IN GUSTS ACROSS
CENTRAL PENNSYLVANIA...AND ADD STRONGER WIND GUSTS TO THE FORECAST
AS NEEDED.
NEAR AND SHORT TERM MODELS PLACE THE AREA OF SHOWERS MAINLY
NORTHEAST OF THE AREA LATE THIS MORNING. AN ATTEMPT TO PLACE THE
BEST CHANCE OF SHOWERS WAS MADE BASED ON THE POSITION OF THE LOW
LEVEL JET AND THE SURFACE TROUGH. .
THE PASSAGE OF THE TROUGH (OR PERHAPS WEAK COLD FRONT) WILL ALLOW
THE DEPTH OF THE MIXED LAYER TO INCREASE. THE INCREASED MIXED LAYER
WILL ALLOW ACCESS TO 25 TO 30 KNOTS OF WIND IN THE WAKE OF THE
TROUGH...AND FOR A FEW HOURS AFTER. THIS SHOULD RESULT IN WEST WINDS
GUSTING TO 25 MPH FOR A TIME THIS AFTERNOON IN JUST ABOUT ALL AREAS.
SKIES SHOULD BECOME PARTLY SUNNY AFTER THE SURFACE TROUGH PASSAGE
(SOUTHERNMOST AREAS MAY BE PARTLY SUNNY THE ENTIRE TIME) AS MIXING
ALLOWS DRIER AIR FROM ABOVE TO BREAK THE LOWER CLOUDS. THE MID DECK
MAY TAKE THE BALANCE OF THE AFTERNOON TO CLEAR THE AREA. THIS IS
MENTIONED BECAUSE OF THE EFFECT ON TEMPERATURES. THE AIRMASS IS EVEN
WARMER AHEAD OF THE TROUGH EARLY THIS MORNING THEN IS WAS MONDAY
AFTERNOON.
WITH ALL THINGS BEING EQUAL...THIS WOULD RESULT IN HIGHER MAXIMUM
TEMPERATURES TODAY. HOWEVER...CLOUD COVER WILL BE A BIG ISSUE. MOST
OF THE REAL WARMING MAY HAVE TO WAIT UNTIL AFTER THE WINDS SHIFT AND
BETTER MIXING CAN OCCUR. THIS MEANS THAT HIGHS MAY NOT GET QUITE AS
HIGH AS THE HIGHER GFS MOS NUMBER SUGGEST. FOR NOW...A BLEND OF MOS
NUMBERS WAS USED FOR HIGHS TODAY...AND THIS COULD BE TWEAKED LATER
THIS MORNING IF THE CLOUD COVER IS NOT AS EXTENSIVE AS IT LOOKS LIKE
IT WILL BE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE SURFACE FRONT/TROUGH WILL STALL SOUTH OF THE AREA THIS EVENING.
WHILE THERE IS SOME MODEL SPREAD ON JUST HOW FAR SOUTH THE FRONT
GETS...ALL SHORT RANGE MODELS DEVELOP A SURFACE LOW ON THE FRONT. AT
THIS POINT...THE POSITION OF THE SURFACE LOW DOES NOT LOOK AS
IMPORTANT AS THE POSITION OF THE MID LEVEL FORCING FOR RAIN TONIGHT.
ALL SHORT RANGE MODELS SHOW AN AREA OF 700-500 MB FRONTOGENETIC
FORCING DEVELOPING AHEAD OF THE SHORT RANGE APPROACHING FROM THE
WEST. MOST PLACE THE BEST MID LEVEL FORCING ACROSS NORTHEAST
MARYLAND...MUCH OF DELAWARE...AS WELL AS SOUTHERNMOST NEW JERSEY.
THIS PLACEMENT HAS BEEN MORE OR LESS CONSISTENT OVER THE PAST 24
HOURS OR SO...AND WAS USED AS THE BASIS FOR THE BEST CHANCE OF RAIN
LATER TONIGHT.
THE AIRMASS ACROSS SOUTHERN AREAS DOES NOT GET A CHANCE TO DRY OUT
AS CENTRAL AND NORTHERN AREAS DO. THERE COULD BE SOME INITIAL LIGHT
RAIN ACROSS SOUTHERNMOST AREAS BEFORE MIDNIGHT...BUT MOST OF THE
STEADY LIGHT RAIN SHOULD OCCUR WITH THE DEVELOPMENT AND MOVEMENT OF
THE BEST MID LEVEL FORCING. THE BEST MID LEVEL LIFT SHOULD OCCUR
BETWEEN 0600 UTC AND 1200 UTC THURSDAY...WITH THE EMPHASIS LATER IN
THE PERIOD.
AGAIN...WHILE THERE IS SOME DIFFERENCE IN THE PLACEMENT OF THE
NORTHERN EDGE OF THE PRECIPITATION WITH THIS EVENT...IT WOULD APPEAR
THAT MOST PLACES SOUTH OF A KTHV-KILG-KACY SHOULD REMAIN DRY THROUGH
1200 UTC THURSDAY. THERE COULD BE SOME PLAY IN THE POSITION OF THIS
LINE...AND A SLIGHT CHANCE OF RAIN WILL BE FORECAST NORTH OF IT TO
INDICATE SOME REMAINING UNCERTAINTY.
MUCH OF THE REST OF THE AREA SHOULD REMAIN DRY...WITH VARYING CLOUD
HEIGHTS OVERNIGHT. CLEARING ACROSS THE NORTH SHOULD BE REPLACED BY
HIGH ALTOSTRATUS...AND CENTRAL AREAS COULD SEE THE MID CLOUDS LOWER
TOWARD DAYBREAK. IN ANY EVENT...THE MOS BLEND LOOKS OK FOR LOWS
TONIGHT...AND THERE WAS A LEAN TOWARD THE HIGHER NAM MOS NUMBERS DUE
TO THE CLOUDS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODEL GUIDANCE DOES NOT ENGENDER MUCH IN THE WAY OF CONFIDENCE AS
SOLUTIONS SEEM TO VARY AT LEAST SOMEWHAT FROM RUN TO RUN...AS WELL
AS MODEL TO MODEL FOR THE LATTER TIME PERIODS. AN INITIAL ZONAL FLOW
ALOFT FOR MUCH OF THE COUNTRY LOOKS TO SEGUE INTO SOMEWHAT OF A
BLOCKING REGIME LATER FRIDAY AND OVER THE WEEKEND...THEN RETURN TO
MORE OF A ZONAL CONFIGURATION EARLY NEXT WEEK. FOR OUR AREA, IT
APPEARS THAT WE WILL HAVE SEVERAL UPPER TROUGH PASSAGES IN A HIGH
SPEED UPPER FLOW PATTERN. HOW THIS TRANSLATES TO SENSIBLE WEATHER
FOR OUR AREA REMAINS PROBLEMATICAL. AT THE SURFACE, THE 00Z GFS
TRANSITS A WAVE ALONG THE STALLED BOUNDARY TO OUR SOUTH THURSDAY,
MAINLY IN THE MORNING, FOLLOWED BY A PERIOD OF HIGH PRESSURE INTO
SATURDAY. THEN, THE GFS RESOLVES ANOTHER WAVE PASSING TO OUR SOUTH
SATURDAY NIGHT INTO SUNDAY. THIS LOW IS EJECTED FROM A CLOSED UPPER
LOW OVER THE MID MISSISSIPPI VALLEY, BUT THEN IS CAPTURED BY A
DEVELOPING UPPER TROUGH MOVING SOUTHEASTWARD FROM THE EASTERN GREAT
LAKES BY SUNDAY. THE 00Z ECMWF DECLINES TO PASS THE SURFACE LOW EAST
OF ITS MIDWEST UPPER CLOSED LOW...INSTEAD BUILDING HIGH PRESSURE FOR
US FOR THE WEEKEND AND BRINGING A FRONT INTO THE AREA FOR MONDAY
NIGHT INTO EARLY TUESDAY. WITH DIFFERENT FORECASTS, IT WAS DECIDED
JUST TO INTRODUCE SLIGHT CHANCE PROBABILITIES TO OUR FAR SOUTHERN
ZONES SATURDAY NIGHT. THICKNESS CONSIDERATIONS DICTATED THAT A MIX
OF RAIN OR SNOW SHOWERS BE USED ON THE NORTHERN FRINGE OF THIS LOW
CHANCE EVENT. THIS WILL CARRY INTO THE INHERITED CHANCE
PROBABILITIES FOR SUNDAY AND INTO MONDAY. IT MAY TURN OUT THAT THE
LOW CHANCE PROBABILITIES FOR LATER SUNDAY INTO MONDAY ARE OVERDONE,
BUT FOR NOW CONTINUITY WAS USED. THEN, ONLY A SLIGHT CHANCE WAS
INTRODUCED FOR MONDAY NIGHT AND TUESDAY FOR CENTRAL AND NORTHERN
ZONES WITH THE INDICATED FRONTAL PASSAGE ON THE ECMWF.
ALTHOUGH TEMPERATURES MAY DIP AND RECOVER SLIGHTLY THROUGH THE
PERIOD, THEY ARE EXPECTED TO REMAIN ABOVE NORMAL THROUGH NEXT
TUESDAY AS COLD AIR REMAINS UNABLE TO PENETRATE SOUTHWARD TO OUR
LATITUDE.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A WAVE OF LOW PRESSURE PASSING TO OUR SOUTH THURSDAY...MAINLY IN THE
MORNING...SHOULD HAVE LITTLE EFFECT FOR OUR TAF SITES. ANOTHER WAVE
MAY PASS TO OUR SOUTH SATURDAY NIGHT INTO SUNDAY...BUT EVEN IF THAT
MATERIALIZED IT SHOULD HAVE MINIMAL IMPACT AS WELL. SO, VFR
CONDITIONS ARE EXPECTED THURSDAY AND RIGHT THROUGH THE OUTLOOK
PERIOD. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
THE APPROACHING LOW LEVEL JET IS DROPPING ENOUGH LOW LEVEL MOMENTUM
AT THE HIGHER PLATFORMS ON THE DELAWARE BAY FOR GUSTS AT OR ABOVE 25
KNOTS. SINCE THE LOW LEVEL JET WILL TAKE MOST OF THE MORNING TO
CLEAR THE REGION...A SMALL CRAFT ADVISORY WAS ISSUED FOR THE
DELAWARE BAY. THIS IS IN ADDITION TO THE SMALL CRAFT ADVISORY THAT
WAS IN PLACE FOR THE OCEAN WATERS...DUE MAINLY TO THE LOW LEVEL JET.
THE SURFACE GRADIENT EARLY THIS MORNING LOOKS AS THOUGH IT CAN
SUPPORT SMALL CRAFT WIND GUSTS ON THE OCEAN...AND THE GRADIENT
SHOULD REMAIN IN PLACE AHEAD OF THE SURFACE TROUGH. MODEL SOUNDINGS
DO NOT SHOW THAT MUCH MOMENTUM TRANSFER (NOT UNUSUAL DURING STRONG
WARM AIR ADVECTION SCENARIOS)...SO THE SMALL CRAFT WINDS PROBABLY
OCCUR MOSTLY BEFORE 1500 UTC. THE SAME IS TRUE ON DELAWARE
BAY...WHERE THE STRONGEST WINDS PROBABLY OCCUR NEARSHORE AND ACROSS
THE MOUTH OF THE BAY.
IN ADDITION...THE SOUTHWEST WIND IS CREATING A SWELL...WHICH
COMBINED WITH THE LOCAL WIND WAVE IS NEAR 5 FEET. THIS PROBABLY
PERSISTS THROUGH THE SURFACE TROUGH PASSAGE...AND PERHAPS A FEW
HOURS AFTER...AS THE SWELL SORTS ITSELF OUT. BASED ON THE
ABOVE...THERE IS NO CHANGE TO THE TIMING OF THE SMALL CRAFT ADVISORY
THROUGH EARLY AFTERNOON.
MODEL SOUNDINGS SHOW SOME MOMENTUM TRANSFER THIS AFTERNOON AS THE
GRADIENT INCREASES AND SLIGHTLY COOLER AIR STREAMS OUT OVER THE
WATERS. RIGHT NOW...THE GRADIENT DOES NOT APPEAR TO SUPPORT SMALL
CRAFT WINDS...AND GUSTS OF THAT MAGNITUDE COULD BE CONFINED TO THE
IMMEDIATE COAST. LATER FORECASTS MAY HAVE TO ACCOUNT FOR THIS AFTER
THE TROUGH PASSES.
THE BEST MOMENTUM ENDS THIS EVENING...AND WINDS AND SEAS WILL DROP
BELOW SMALL CRAFT LEVELS. A SURFACE LOW DEVELOPING ON THE PASSING
SURFACE TROUGH/FRONT SHOULD STILL BE IN THE INCIPIENT STAGE LATER
TONIGHT AS IT APPROACHES THE NORTH CAROLINA/VIRGINIA BORDER. WINDS
WILL SHIFT TO THE NORTH AND NORTHEAST IN RESPONSE TO THE SURFACE LOW
DEVELOPMENT...BUT RIGHT NOW IT APPEARS AS THOUGH WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS THROUGH 1200 UTC THURSDAY.
A WAVE PASSING JUST SOUTH OF OUR AREA THURSDAY MORNING WILL CAUSE
THE GRADIENT TO TIGHTEN UP...PROBABLY ENOUGH TO INDUCE SMALL CRAFT
ADVISORY LEVEL WINDS. SEAS WILL LIKELY RESPOND AS WELL, BUT THEY ARE
NOT EXPECTED TO RISE ABOVE 4 FEET AT THIS TIME. HIGH PRESSURE WILL
BUILD ACROSS OUR REGION LATER THURSDAY AND REMAIN INTO SATURDAY.
ANOTHER WAVE OF LOW PRESSURE MIGHT PASS JUST TO OUR SOUTH SATURDAY
NIGHT INTO SUNDAY. IF IT DOES, IT COULD INTENSIFY AS IT MOVES OUT
INTO THE WESTERN ATLANTIC...AND THIS MAY RESULT IN MORE SMALL
CRAFT ADVISORY CONDITIONS, BUT FOR NOW LOW CONFIDENCE EXISTS ON
THAT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-
431-450>455.
&&
$$
SYNOPSIS...
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...
AVIATION...HAYES
MARINE...HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
302 AM EST WED FEB 1 2012
.SYNOPSIS...
LOW PRESSURE MOVING EASTWARD THROUGH SOUTHERN CANADA AND INTO
NORTHERN NEW ENGLAND TODAY WILL BRING A COLD FRONT THROUGH OUR AREA
THIS AFTERNOON...WHICH WILL STALL TO OUR SOUTH TONIGHT. ANOTHER WAVE
OF LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS
JUST SOUTH OF OUR AREA THURSDAY MORNING. HIGH PRESSURE WILL THEN
RETURN FOR LATER THURSDAY INTO SATURDAY. ANOTHER AREA OF LOW
PRESSURE MIGHT RIDE JUST SOUTH OF OUR REGION LATER SATURDAY NIGHT
INTO SUNDAY...OTHERWISE HIGH PRESSURE IS EXPECTED TO BUILD INTO
MONDAY. ANOTHER FRONT MAY AFFECT OUR REGION MONDAY NIGHT INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN FORECAST PROBLEM FOR TODAY WILL BE THE TIMING AND EXTENT OF
SHOWERS...MAINLY THIS MORNING.
AN AREA OF SHOWERS CONTINUES TO EXPAND TO THE WEST ACROSS WEST
CENTRAL PENNSYLVANIA EARLY THIS MORNING. THE AREA OF SHOWERS IS
COINCIDENT WITH THE POSITION OF THE LOW LEVEL JET (NEAR 45 KNOTS AT
925 MB BASED ON THE 0000 UTC UPPER AIR ANALYSIS). THE SHOWERS ARE
FORMING ON WHAT APPEARS TO BE A SURFACE TROUGH...WITH NOT MUCH
THERMAL CONTRAST ALONG IT. AS THE LOW LEVEL JET STREAMS MOISTURE
ALONG THE TROUGH...THE SHOWER ACTIVITY SHOULD MAINTAIN ITSELF AS IT
REACHES THE LEHIGH VALLEY BEFORE 400 AM.
THERE IS A SMALL CONCERN FOR GUSTY WINDS WITH THE PASSAGE OF THE
SHOWERS THIS MORNING. A PEAK GUST OF 39 KNOTS WAS NOTED AT KJST
BEFORE 0700 UTC...IN THE VICINITY OF SOME OF THE SHOWERS. THIS
APPEARS TO BE CLOSE TO THE NOSE OF THE 45 KNOT LOW LEVEL...AND THE
CONVECTIVE NATURE OF THE SHOWERS COULD BE HELPING TO MIX MOMENTUM
DOWN. FOR NOW...WILL CONTINUE TO MONITOR THE TRENDS IN GUSTS ACROSS
CENTRAL PENNSYLVANIA...AND ADD STRONGER WIND GUSTS TO THE FORECAST
AS NEEDED.
NEAR AND SHORT TERM MODELS PLACE THE AREA OF SHOWERS ALONG THE I-95
CORRIDOR CLOSE TO SUNRISE...AND MAINLY NORTHEAST OF THE AREA LATE
THIS MORNING. AN ATTEMPT TO PLACE THE BEST CHANCE OF SHOWERS WAS
MADE BASED ON THE POSITION OF THE LOW LEVEL JET AND THE SURFACE
TROUGH. MOST OF THE SHOWER ACTIVITY SHOULD MISS NORTHEAST
MARYLAND...DELAWARE AND SOUTHERN NEW JERSEY. HOWEVER...SMALL
CONVECTIVE LOOKING SHOWERS HAVE DEVELOPED IN THESE AREAS...AND A
CHANCE OF SHOWERS WILL HAVE TO BE CARRIED FOR THIS ACTIVITY THROUGH
AT LEAST SUNRISE.
THE PASSAGE OF THE TROUGH (OR PERHAPS WEAK COLD FRONT) WILL ALLOW
THE DEPTH OF THE MIXED LAYER TO INCREASE. THE INCREASED MIXED LAYER
WILL ALLOW ACCESS TO 25 TO 30 KNOTS OF WIND IN THE WAKE OF THE
TROUGH...AND FOR A FEW HOURS AFTER. THIS SHOULD RESULT IN WEST WINDS
GUSTING TO 25 MPH FOR A TIME THIS AFTERNOON IN JUST ABOUT ALL AREAS.
SKIES SHOULD BECOME PARTLY SUNNY AFTER THE SURFACE TROUGH PASSAGE
(SOUTHERNMOST AREAS MAY BE PARTLY SUNNY THE ENTIRE TIME) AS MIXING
ALLOWS DRIER AIR FROM ABOVE TO BREAK THE LOWER CLOUDS. THE MID DECK
MAY TAKE THE BALANCE OF THE AFTERNOON TO CLEAR THE AREA. THIS IS
MENTIONED BECAUSE OF THE EFFECT ON TEMPERATURES. THE AIRMASS IS EVEN
WARMER AHEAD OF THE TROUGH EARLY THIS MORNING THEN IS WAS MONDAY
AFTERNOON.
WITH ALL THINGS BEING EQUAL...THIS WOULD RESULT IN HIGHER MAXIMUM
TEMPERATURES TODAY. HOWEVER...CLOUD COVER WILL BE A BIG ISSUE. MOST
OF THE REAL WARMING MAY HAVE TO WAIT UNTIL AFTER THE WINDS SHIFT AND
BETTER MIXING CAN OCCUR. THIS MEANS THAT HIGHS MAY NOT GET QUITE AS
HIGH AS THE HIGHER GFS MOS NUMBER SUGGEST. FOR NOW...A BLEND OF MOS
NUMBERS WAS USED FOR HIGHS TODAY...AND THIS COULD BE TWEAKED LATER
THIS MORNING IF THE CLOUD COVER IS NOT AS EXTENSIVE AS IT LOOKS LIKE
IT WILL BE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE SURFACE FRONT/TROUGH WILL STALL SOUTH OF THE AREA THIS EVENING.
WHILE THERE IS SOME MODEL SPREAD ON JUST HOW FAR SOUTH THE FRONT
GETS...ALL SHORT RANGE MODELS DEVELOP A SURFACE LOW ON THE FRONT. AT
THIS POINT...THE POSITION OF THE SURFACE LOW DOES NOT LOOK AS
IMPORTANT AS THE POSITION OF THE MID LEVEL FORCING FOR RAIN TONIGHT.
ALL SHORT RANGE MODELS SHOW AN AREA OF 700-500 MB FRONTOGENETIC
FORCING DEVELOPING AHEAD OF THE SHORT RANGE APPROACHING FROM THE
WEST. MOST PLACE THE BEST MID LEVEL FORCING ACROSS NORTHEAST
MARYLAND...MUCH OF DELAWARE...AS WELL AS SOUTHERNMOST NEW JERSEY.
THIS PLACEMENT HAS BEEN MORE OR LESS CONSISTENT OVER THE PAST 24
HOURS OR SO...AND WAS USED AS THE BASIS FOR THE BEST CHANCE OF RAIN
LATER TONIGHT.
THE AIRMASS ACROSS SOUTHERN AREAS DOES NOT GET A CHANCE TO DRY OUT
AS CENTRAL AND NORTHERN AREAS DO. THERE COULD BE SOME INITIAL LIGHT
RAIN ACROSS SOUTHERNMOST AREAS BEFORE MIDNIGHT...BUT MOST OF THE
STEADY LIGHT RAIN SHOULD OCCUR WITH THE DEVELOPMENT AND MOVEMENT OF
THE BEST MID LEVEL FORCING. THE BEST MID LEVEL LIFT SHOULD OCCUR
BETWEEN 0600 UTC AND 1200 UTC THURSDAY...WITH THE EMPHASIS LATER IN
THE PERIOD.
AGAIN...WHILE THERE IS SOME DIFFERENCE IN THE PLACEMENT OF THE
NORTHERN EDGE OF THE PRECIPITATION WITH THIS EVENT...IT WOULD APPEAR
THAT MOST PLACES SOUTH OF A KTHV-KILG-KACY SHOULD REMAIN DRY THROUGH
1200 UTC THURSDAY. THERE COULD BE SOME PLAY IN THE POSITION OF THIS
LINE...AND A SLIGHT CHANCE OF RAIN WILL BE FORECAST NORTH OF IT TO
INDICATE SOME REMAINING UNCERTAINTY.
MUCH OF THE REST OF THE AREA SHOULD REMAIN DRY...WITH VARYING CLOUD
HEIGHTS OVERNIGHT. CLEARING ACROSS THE NORTH SHOULD BE REPLACED BY
HIGH ALTOSTRATUS...AND CENTRAL AREAS COULD SEE THE MID CLOUDS LOWER
TOWARD DAYBREAK. IN ANY EVENT...THE MOS BLEND LOOKS OK FOR LOWS
TONIGHT...AND THERE WAS A LEAN TOWARD THE HIGHER NAM MOS NUMBERS DUE
TO THE CLOUDS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODEL GUIDANCE DOES NOT ENGENDER MUCH IN THE WAY OF CONFIDENCE AS
SOLUTIONS SEEM TO VARY AT LEAST SOMEWHAT FROM RUN TO RUN...AS WELL
AS MODEL TO MODEL FOR THE LATTER TIME PERIODS. AN INITIAL ZONAL FLOW
ALOFT FOR MUCH OF THE COUNTRY LOOKS TO SEGUE INTO SOMEWHAT OF A
BLOCKING REGIME LATER FRIDAY AND OVER THE WEEKEND...THEN RETURN TO
MORE OF A ZONAL CONFIGURATION EARLY NEXT WEEK. FOR OUR AREA, IT
APPEARS THAT WE WILL HAVE SEVERAL UPPER TROUGH PASSAGES IN A HIGH
SPEED UPPER FLOW PATTERN. HOW THIS TRANSLATES TO SENSIBLE WEATHER
FOR OUR AREA REMAINS PROBLEMATICAL. AT THE SURFACE, THE 00Z GFS
TRANSITS A WAVE ALONG THE STALLED BOUNDARY TO OUR SOUTH THURSDAY,
MAINLY IN THE MORNING, FOLLOWED BY A PERIOD OF HIGH PRESSURE INTO
SATURDAY. THEN, THE GFS RESOLVES ANOTHER WAVE PASSING TO OUR SOUTH
SATURDAY NIGHT INTO SUNDAY. THIS LOW IS EJECTED FROM A CLOSED UPPER
LOW OVER THE MID MISSISSIPPI VALLEY, BUT THEN IS CAPTURED BY A
DEVELOPING UPPER TROUGH MOVING SOUTHEASTWARD FROM THE EASTERN GREAT
LAKES BY SUNDAY. THE 00Z ECMWF DECLINES TO PASS THE SURFACE LOW EAST
OF ITS MIDWEST UPPER CLOSED LOW...INSTEAD BUILDING HIGH PRESSURE FOR
US FOR THE WEEKEND AND BRINGING A FRONT INTO THE AREA FOR MONDAY
NIGHT INTO EARLY TUESDAY. WITH DIFFERENT FORECASTS, IT WAS DECIDED
JUST TO INTRODUCE SLIGHT CHANCE PROBABILITIES TO OUR FAR SOUTHERN
ZONES SATURDAY NIGHT. THICKNESS CONSIDERATIONS DICTATED THAT A MIX
OF RAIN OR SNOW SHOWERS BE USED ON THE NORTHERN FRINGE OF THIS LOW
CHANCE EVENT. THIS WILL CARRY INTO THE INHERITED CHANCE
PROBABILITIES FOR SUNDAY AND INTO MONDAY. IT MAY TURN OUT THAT THE
LOW CHANCE PROBABILITIES FOR LATER SUNDAY INTO MONDAY ARE OVERDONE,
BUT FOR NOW CONTINUITY WAS USED. THEN, ONLY A SLIGHT CHANCE WAS
INTRODUCED FOR MONDAY NIGHT AND TUESDAY FOR CENTRAL AND NORTHERN
ZONES WITH THE INDICATED FRONTAL PASSAGE ON THE ECMWF.
ALTHOUGH TEMPERATURES MAY DIP AND RECOVER SLIGHTLY THROUGH THE
PERIOD, THEY ARE EXPECTED TO REMAIN ABOVE NORMAL THROUGH NEXT
TUESDAY AS COLD AIR REMAINS UNABLE TO PENETRATE SOUTHWARD TO OUR
LATITUDE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A WAVE OF LOW PRESSURE PASSING TO OUR SOUTH THURSDAY...MAINLY IN THE
MORNING...SHOULD HAVE LITTLE EFFECT FOR OUR TAF SITES. ANOTHER WAVE
MAY PASS TO OUR SOUTH SATURDAY NIGHT INTO SUNDAY...BUT EVEN IF THAT
MATERIALIZED IT SHOULD HAVE MINIMAL IMPACT AS WELL. SO, VFR
CONDITIONS ARE EXPECTED THURSDAY AND RIGHT THROUGH THE OUTLOOK
PERIOD. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
THE APPROACHING LOW LEVEL JET IS DROPPING ENOUGH LOW LEVEL MOMENTUM
AT THE HIGHER PLATFORMS ON THE DELAWARE BAY FOR GUSTS AT OR ABOVE 25
KNOTS. SINCE THE LOW LEVEL JET WILL TAKE MOST OF THE MORNING TO
CLEAR THE REGION...A SMALL CRAFT ADVISORY WAS ISSUED FOR THE
DELAWARE BAY. THIS IS IN ADDITION TO THE SMALL CRAFT ADVISORY THAT
WAS IN PLACE FOR THE OCEAN WATERS...DUE MAINLY TO THE LOW LEVEL JET.
THE SURFACE GRADIENT EARLY THIS MORNING LOOKS AS THOUGH IT CAN
SUPPORT SMALL CRAFT WIND GUSTS ON THE OCEAN...AND THE GRADIENT
SHOULD REMAIN IN PLACE AHEAD OF THE SURFACE TROUGH. MODEL SOUNDINGS
DO NOT SHOW THAT MUCH MOMENTUM TRANSFER (NOT UNUSUAL DURING STRONG
WARM AIR ADVECTION SCENARIOS)...SO THE SMALL CRAFT WINDS PROBABLY
OCCUR MOSTLY BEFORE 1500 UTC. THE SAME IS TRUE ON DELAWARE
BAY...WHERE THE STRONGEST WINDS PROBABLY OCCUR NEARSHORE AND ACROSS
THE MOUTH OF THE BAY.
IN ADDITION...THE SOUTHWEST WIND IS CREATING A SWELL...WHICH
COMBINED WITH THE LOCAL WIND WAVE IS NEAR 5 FEET. THIS PROBABLY
PERSISTS THROUGH THE SURFACE TROUGH PASSAGE...AND PERHAPS A FEW
HOURS AFTER...AS THE SWELL SORTS ITSELF OUT. BASED ON THE
ABOVE...THERE IS NO CHANGE TO THE TIMING OF THE SMALL CRAFT ADVISORY
THROUGH EARLY AFTERNOON.
MODEL SOUNDINGS SHOW SOME MOMENTUM TRANSFER THIS AFTERNOON AS THE
GRADIENT INCREASES AND SLIGHTLY COOLER AIR STREAMS OUT OVER THE
WATERS. RIGHT NOW...THE GRADIENT DOES NOT APPEAR TO SUPPORT SMALL
CRAFT WINDS...AND GUSTS OF THAT MAGNITUDE COULD BE CONFINED TO THE
IMMEDIATE COAST. LATER FORECASTS MAY HAVE TO ACCOUNT FOR THIS AFTER
THE TROUGH PASSES.
THE BEST MOMENTUM ENDS THIS EVENING...AND WINDS AND SEAS WILL DROP
BELOW SMALL CRAFT LEVELS. A SURFACE LOW DEVELOPING ON THE PASSING
SURFACE TROUGH/FRONT SHOULD STILL BE IN THE INCIPIENT STAGE LATER
TONIGHT AS IT APPROACHES THE NORTH CAROLINA/VIRGINIA BORDER. WINDS
WILL SHIFT TO THE NORTH AND NORTHEAST IN RESPONSE TO THE SURFACE LOW
DEVELOPMENT...BUT RIGHT NOW IT APPEARS AS THOUGH WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS THROUGH 1200 UTC THURSDAY.
A WAVE PASSING JUST SOUTH OF OUR AREA THURSDAY MORNING WILL CAUSE
THE GRADIENT TO TIGHTEN UP...PROBABLY ENOUGH TO INDUCE SMALL CRAFT
ADVISORY LEVEL WINDS. SEAS WILL LIKELY RESPOND AS WELL, BUT THEY ARE
NOT EXPECTED TO RISE ABOVE 4 FEET AT THIS TIME. HIGH PRESSURE WILL
BUILD ACROSS OUR REGION LATER THURSDAY AND REMAIN INTO SATURDAY.
ANOTHER WAVE OF LOW PRESSURE MIGHT PASS JUST TO OUR SOUTH SATURDAY
NIGHT INTO SUNDAY. IF IT DOES, IT COULD INTENSIFY AS IT MOVES OUT
INTO THE WESTERN ATLANTIC...AND THIS MAY RESULT IN MORE SMALL
CRAFT ADVISORY CONDITIONS, BUT FOR NOW LOW CONFIDENCE EXISTS ON
THAT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...
AVIATION...HAYES/
MARINE...HAYES/
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
133 AM EST WED FEB 1 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL DRAG A COLD FRONT THROUGH OUR AREA
WEDNESDAY AFTERNOON BEFORE STALLING TO OUR SOUTH. ANOTHER AREA OF
LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS JUST
SOUTH OF OUR AREA ON THURSDAY. HIGH PRESSURE WILL THEN RETURN FOR
LATE THURSDAY THROUGH SUNDAY. ANOTHER SYSTEM MAY IMPACT THE REGION
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THIN SPOTS IN THE MID DECK...AS WELL AS RELATIVELY CALM WINDS IN
PROTECTED AREAS...HAS ALLOWED TEMPERATURES TO DROP IN THESE PLACES
AS A RESULT OF RADIATIONAL COOLING. ELSEWHERE...WITH A MID DECK IN
PLACE OR MOVING INTO PLACE...WITH A LIGHT BUT STEADY SOUTHWEST
WIND...TEMPERATURES HAVE BEEN SLOW TO DROP. OTHER THAN
TEMPERATURES IN THE PROTECTED AREAS WARMING WITH END OF
RADIATIONAL COOLING...NO SIGNIFICANT CHANGES WERE MADE TO THE
OVERNIGHT TEMPERATURES.
A BAND OF SHOWERS IS DEVELOPING ON A SURFACE TROUGH ACROSS WEST
CENTRAL PENNSYLVANIA...WHICH EXTENDS BACK INTO SOUTHEAST OHIO. THE
SHOWERS LOOK TO BE FORMING ON THE NOSE OF THE 45 KNOT LOW LEVEL
JET SEEN ON THE 0000 UTC 925 MB ANALYSIS. MOISTURE IS BEING
FUNNELED UP ALONG THE TROUGH...WITH PRECIPITABLE WATER VALUES NEAR
0.90 INCHES HELPING THE SHOWER DEVELOPMENT.
WHILE 0000 UTC SOUNDINGS WHERE DRY...THE BAND OF SHOWERS SHOULD
NOT HAVE MUCH TROUGH MOVING EAST. EXTRAPOLATION AND THE LATEST
HRRR RUN SUGGEST THAT THE LEADING EDGE OF THE SHOWERS COULD BE IN
THE LEHIGH VALLEY BEFORE 0900 UTC...AND THE AREAL EXTENT OF THE
SHOWERS WAS INCREASED TO ACCOMMODATE THE TIMING. THE COLUMN IS MUCH
TOO WARM FOR ANYTHING OTHER THAN RAIN SHOWERS.
THE BAND OF SHOWERS SHOULD BE IN THE PHILADELPHIA REGION NEAR OR
JUST AFTER DAYBREAK. THE SHOWERS CHANCES WERE INCREASED TO THE
SOUTHWEST LATE TONIGHT TO ACCOUNT FOR THE SHOWERS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
THE FRONT WILL CROSS OUR REGION WEDNESDAY. THE THREAT OF SHOWERS
WILL CONTINUE THROUGH THE MORNING HOURS BUT WILL BE ENDING WITH
THE FRONTAL PASSAGE AROUND MIDDAY. SINCE THE FRONTAL ALIGNMENT
WILL BE ALMOST PARALLEL TO THE UPPER AIR FLOW, THE TEMPERATURE
GRADIENT BEHIND THE FRONT WILL BE NEGLIGIBLE. THAT WILL MEAN
ANOTHER UNSEASONABLY MILD DAY WITH HIGHS RANGING FROM AROUND 50
NORTH TO THE LOWER AND MID 60S SOUTH. SKIES WILL BEGIN TO CLEAR
LATER IN THE DAY AS THE FRONT DRIFTS OFF TO THE SOUTH AND EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT MOVES THROUGH WEDNESDAY AND THEN STALLS TO OUR SOUTH. A
LOW PRESSURE SYSTEM WILL DEVELOP AND TRAVEL ALONG THE STALLED
BOUNDARY ON THURSDAY. THIS WILL BRING THE GREATEST CHANCES FOR
MORE RAIN ACROSS THE SOUTHERN PORTIONS OF OUR FORECAST AREA AS THE
CENTER OF THE LOW IS FORECAST TO STAY NEAR OR JUST SOUTH OF OUR
AREA. THIS SYSTEM MOVES THROUGH QUICKLY AND IS WELL OFFSHORE BY
EARLY FRIDAY.
HIGH PRESSURE THEN SETTLES ACROSS OUR AREA FOR FRIDAY INTO SATURDAY.
THIS WILL KEEP THE FORECAST DRY AS THE HIGH REMAINS ACROSS THE
FORECAST AREA BEFORE STARTING TO SLIDE EASTWARD LATE IN THE DAY ON
SATURDAY.
ANOTHER DAY, ANOTHER RUN OF THE MODELS AND YET ANOTHER FLIP FLOP
SCENARIO. THE GUIDANCE IS HAVING A HARD TIME FIGURING OUT WHAT TO DO
WITH THE STRONG UPPER LEVEL TROUGH/CUT OFF LOW THAT DIGS DOWN ACROSS
THE WESTERN UNITED STATES LATER THIS WEEK. WITH NO REAL CONSENSUS WE
PREFER TO GO WITH THE STATUS QUO AND MAKE VERY FEW CHANGES TO THE
FORECAST FROM SATURDAY ONWARD.
THE CURRENT TRENDS INDICATE A DRY PERIOD FROM FRIDAY THROUGH MUCH OF
SUNDAY AND MAYBE EVEN INTO MONDAY AS HIGH PRESSURE AT THE SURFACE
CONTROLS OUR WEATHER. AN UPPER LEVEL TROUGH DIGS DOWN ACROSS OUR
AREA ON SUNDAY BUT NOT MUCH MOISTURE IS AROUND TO SUPPORT MUCH
PRECIPITATION. THERE IS SOME CONSENSUS THAT THE CUT OFF LOW TO OUR
WEST STARTS TO OPEN UP AND MOVE EASTWARD DRAGGING A COLD FRONT
ACROSS OUR AREA ON MONDAY NIGHT. A LOW MAY DEVELOP ON THIS FRONT BUT
WILL PROBABLY BE OFFSHORE AND OUT OF THE AREA BY TUESDAY AFTERNOON.
WITH NO BIG CHANGES ANTICIPATED IN THE OVERALL PATTERN THROUGH THE
PERIOD, EXPECT NEAR TO MAINLY ABOVE NORMAL TEMPERATURES TO CONTINUE.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A COLD FRONT CLEARS THE AREA EARLY WEDNESDAY EVENING WITH ANY
REMAINING CLOUDS THINNING FROM NORTH TO SOUTH. HOWEVER, ANY LOWER
CLOUDS MAY TAKE A BIT LONGER ACROSS THE SOUTHERN TERMINALS AS
ANOTHER SYSTEM PASSES JUST TO THE SOUTH OF THE AREA. ALL CONDITIONS
WILL BE VFR AS HIGH PRESSURE BUILDS IN FOR LATE THURSDAY THROUGH
SUNDAY. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
THE HIGHER PLATFORMS ON THE DELAWARE BAY ARE SHOWING GUSTS AT OR
ABOVE 25 KNOTS. THIS WOULD SUGGEST THAT AT LEAST SOME OF THE
MOMENTUM ASSOCIATED WITH THE APPROACHING LOW LEVEL JET IS GETTING
CLOSER TO THE BAY SURFACE. SINCE THE LOW LEVEL JET WILL TAKE
THROUGH AT LEAST MID MORNING TO PASS...A SMALL CRAFT ADVISORY HAS
BEEN RAISED ON THE DELAWARE BAY.
OTHERWISE...HIGH PRESSURE TO OUR SOUTH IS PROVIDING A MILD
SOUTHWEST FLOW ACROSS THE AREA. THIS WILL CONTINUE INTO WEDNESDAY,
WHEN A COLD FRONT WILL MOVE IN FROM THE WEST. THE FRONT WILL CROSS
THE WATERS LATE IN THE DAY WEDNESDAY. THE SOUTHWEST FLOW IS
MAINTAINING SEAS NEAR 5 FEET ESPECIALLY FARTHER OFFSHORE. THE LOW-
LEVEL JET FORECAST TO CROSS PARTS OF THE AREA OVERNIGHT MAY MIX
DOWN SOME AS THE BOUNDARY LAYER COOLS. THE AIRMASS JUST ABOVE THE
WATER MAY NOT BE AS COOL AS LATE LAST NIGHT AND EARLY THIS MORNING
WHEN WINDS GUSTED TO AROUND 25 KNOTS FOR A TIME, HOWEVER THE
POTENTIAL IS THERE BASED ON THE SOUNDINGS. GIVEN THIS AND THE SEAS
AT THE OFFSHORE BUOYS IN THE 4-5 FOOT RANGE, A SMALL CRAFT
ADVISORY IS IN EFFECT UNTIL 18Z WEDNESDAY.
THE COLD FRONT CLEARS OUT BY WEDNESDAY NIGHT BUT THE FLOW BEHIND
THE FRONT ISN`T PARTICULARLY STRONG AND WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY LEVELS. A SECOND SYSTEM WILL
MOVE THROUGH ON THURSDAY AND THIS SYSTEM WILL CAUSE THE GRADIENT
TO TIGHTEN UP JUST ENOUGH TO INDUCE SMALL CRAFT ADVISORY LEVEL
WINDS TO OCCUR. SEAS MAY BRIEFLY INCREASE AS WELL BUT THEY ARE NOT
EXPECTED TO GO ABOVE 4 FEET AT THIS TIME.
HIGH PRESSURE WILL BUILD ACROSS THE REGION LATE THURSDAY AND REMAIN
NEARBY THROUGH THE WEEKEND HELP TO KEEP THE WINDS AND SEAS BELOW
ADVISORY CRITERIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NJZ025-
026.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ450>455.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...GORSE
SHORT TERM...RPW
LONG TERM...MEOLA
AVIATION...HAYES/MEOLA
MARINE...GORSE/MEOLA/RPW/HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1215 AM EST WED FEB 1 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL DRAG A COLD FRONT THROUGH OUR AREA
WEDNESDAY AFTERNOON BEFORE STALLING TO OUR SOUTH. ANOTHER AREA OF
LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS JUST
SOUTH OF OUR AREA ON THURSDAY. HIGH PRESSURE WILL THEN RETURN FOR
LATE THURSDAY THROUGH SUNDAY. ANOTHER SYSTEM MAY IMPACT THE REGION
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THIN SPOTS IN THE MID DECK...AS WELL AS RELATIVELY CALM WINDS IN
PROTECTED AREAS...HAS ALLOWED TEMPERATURES TO DROP IN THESE PLACES
AS A RESULT OF RADIATIONAL COOLING. ELSEWHERE...WITH A MID DECK IN
PLACE OR MOVING INTO PLACE...WITH A LIGHT BUT STEADY SOUTHWEST
WIND...TEMPERATURES HAVE BEEN SLOW TO DROP. OTHER THAN
TEMPERATURES IN THE PROTECTED AREAS WARMING WITH END OF
RADIATIONAL COOLING...NO SIGNIFICANT CHANGES WERE MADE TO THE
OVERNIGHT TEMPERATURES.
A BAND OF SHOWERS IS DEVELOPING ON A SURFACE TROUGH ACROSS WEST
CENTRAL PENNSYLVANIA...WHICH EXTENDS BACK INTO SOUTHEAST OHIO. THE
SHOWERS LOOK TO BE FORMING ON THE NOSE OF THE 45 KNOT LOW LEVEL
JET SEEN ON THE 0000 UTC 925 MB ANALYSIS. MOISTURE IS BEING
FUNNELED UP ALONG THE TROUGH...WITH PRECIPITABLE WATER VALUES NEAR
0.90 INCHES HELPING THE SHOWER DEVELOPMENT.
WHILE 0000 UTC SOUNDINGS WHERE DRY...THE BAND OF SHOWERS SHOULD
NOT HAVE MUCH TROUGH MOVING EAST. EXTRAPOLATION AND THE LATEST
HRRR RUN SUGGEST THAT THE LEADING EDGE OF THE SHOWERS COULD BE IN
THE LEHIGH VALLEY BEFORE 0900 UTC...AND THE AREAL EXTENT OF THE
SHOWERS WAS INCREASED TO ACCOMMODATE THE TIMING. THE COLUMN IS MUCH
TOO WARM FOR ANYTHING OTHER THAN RAIN SHOWERS.
THE BAND OF SHOWERS SHOULD BE IN THE PHILADELPHIA REGION NEAR OR
JUST AFTER DAYBREAK. THE SHOWERS CHANCES WERE INCREASED TO THE
SOUTHWEST LATE TONIGHT TO ACCOUNT FOR THE SHOWERS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
THE FRONT WILL CROSS OUR REGION WEDNESDAY. THE THREAT OF SHOWERS
WILL CONTINUE THROUGH THE MORNING HOURS BUT WILL BE ENDING WITH
THE FRONTAL PASSAGE AROUND MIDDAY. SINCE THE FRONTAL ALIGNMENT
WILL BE ALMOST PARALLEL TO THE UPPER AIR FLOW, THE TEMPERATURE
GRADIENT BEHIND THE FRONT WILL BE NEGLIGIBLE. THAT WILL MEAN
ANOTHER UNSEASONABLY MILD DAY WITH HIGHS RANGING FROM AROUND 50
NORTH TO THE LOWER AND MID 60S SOUTH. SKIES WILL BEGIN TO CLEAR
LATER IN THE DAY AS THE FRONT DRIFTS OFF TO THE SOUTH AND EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT MOVES THROUGH WEDNESDAY AND THEN STALLS TO OUR SOUTH. A
LOW PRESSURE SYSTEM WILL DEVELOP AND TRAVEL ALONG THE STALLED
BOUNDARY ON THURSDAY. THIS WILL BRING THE GREATEST CHANCES FOR
MORE RAIN ACROSS THE SOUTHERN PORTIONS OF OUR FORECAST AREA AS THE
CENTER OF THE LOW IS FORECAST TO STAY NEAR OR JUST SOUTH OF OUR
AREA. THIS SYSTEM MOVES THROUGH QUICKLY AND IS WELL OFFSHORE BY
EARLY FRIDAY.
HIGH PRESSURE THEN SETTLES ACROSS OUR AREA FOR FRIDAY INTO SATURDAY.
THIS WILL KEEP THE FORECAST DRY AS THE HIGH REMAINS ACROSS THE
FORECAST AREA BEFORE STARTING TO SLIDE EASTWARD LATE IN THE DAY ON
SATURDAY.
ANOTHER DAY, ANOTHER RUN OF THE MODELS AND YET ANOTHER FLIP FLOP
SCENARIO. THE GUIDANCE IS HAVING A HARD TIME FIGURING OUT WHAT TO DO
WITH THE STRONG UPPER LEVEL TROUGH/CUT OFF LOW THAT DIGS DOWN ACROSS
THE WESTERN UNITED STATES LATER THIS WEEK. WITH NO REAL CONSENSUS WE
PREFER TO GO WITH THE STATUS QUO AND MAKE VERY FEW CHANGES TO THE
FORECAST FROM SATURDAY ONWARD.
THE CURRENT TRENDS INDICATE A DRY PERIOD FROM FRIDAY THROUGH MUCH OF
SUNDAY AND MAYBE EVEN INTO MONDAY AS HIGH PRESSURE AT THE SURFACE
CONTROLS OUR WEATHER. AN UPPER LEVEL TROUGH DIGS DOWN ACROSS OUR
AREA ON SUNDAY BUT NOT MUCH MOISTURE IS AROUND TO SUPPORT MUCH
PRECIPITATION. THERE IS SOME CONSENSUS THAT THE CUT OFF LOW TO OUR
WEST STARTS TO OPEN UP AND MOVE EASTWARD DRAGGING A COLD FRONT
ACROSS OUR AREA ON MONDAY NIGHT. A LOW MAY DEVELOP ON THIS FRONT BUT
WILL PROBABLY BE OFFSHORE AND OUT OF THE AREA BY TUESDAY AFTERNOON.
WITH NO BIG CHANGES ANTICIPATED IN THE OVERALL PATTERN THROUGH THE
PERIOD, EXPECT NEAR TO MAINLY ABOVE NORMAL TEMPERATURES TO CONTINUE.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A COLD FRONT CLEARS THE AREA EARLY WEDNESDAY EVENING WITH ANY
REMAINING CLOUDS THINNING FROM NORTH TO SOUTH. HOWEVER, ANY LOWER
CLOUDS MAY TAKE A BIT LONGER ACROSS THE SOUTHERN TERMINALS AS
ANOTHER SYSTEM PASSES JUST TO THE SOUTH OF THE AREA. ALL CONDITIONS
WILL BE VFR AS HIGH PRESSURE BUILDS IN FOR LATE THURSDAY THROUGH
SUNDAY. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
HIGH PRESSURE TO OUR SOUTH IS PROVIDING A MILD SOUTHWEST FLOW
ACROSS THE AREA. THIS WILL CONTINUE INTO WEDNESDAY, WHEN A COLD
FRONT WILL MOVE IN FROM THE WEST. THE FRONT WILL CROSS THE WATERS
LATE IN THE DAY WEDNESDAY. THE SOUTHWEST FLOW IS MAINTAINING SEAS
NEAR 5 FEET ESPECIALLY FARTHER OFFSHORE. THE LOW-LEVEL JET
FORECAST TO CROSS PARTS OF THE AREA OVERNIGHT MAY MIX DOWN SOME AS
THE BOUNDARY LAYER COOLS. THE AIRMASS JUST ABOVE THE WATER MAY NOT
BE AS COOL AS LATE LAST NIGHT AND EARLY THIS MORNING WHEN WINDS
GUSTED TO AROUND 25 KNOTS FOR A TIME, HOWEVER THE POTENTIAL IS THERE
BASED ON THE SOUNDINGS. GIVEN THIS AND THE SEAS AT THE OFFSHORE
BUOYS IN THE 4-5 FOOT RANGE, A SMALL CRAFT ADVISORY IS IN EFFECT
UNTIL 18Z WEDNESDAY. WE WILL HOLD OFF ON DELAWARE BAY GIVEN THE
SOUTHWESTERLY TRAJECTORY. WINDS WILL BEGIN TO SWING AROUND TO THE
WEST TOWARD WEDNESDAY EVENING.
THE COLD FRONT CLEARS OUT BY WEDNESDAY NIGHT BUT THE FLOW BEHIND
THE FRONT ISN`T PARTICULARLY STRONG AND WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY LEVELS. A SECOND SYSTEM WILL
MOVE THROUGH ON THURSDAY AND THIS SYSTEM WILL CAUSE THE GRADIENT
TO TIGHTEN UP JUST ENOUGH TO INDUCE SMALL CRAFT ADVISORY LEVEL
WINDS TO OCCUR. SEAS MAY BRIEFLY INCREASE AS WELL BUT THEY ARE NOT
EXPECTED TO GO ABOVE 4 FEET AT THIS TIME.
HIGH PRESSURE WILL BUILD ACROSS THE REGION LATE THURSDAY AND REMAIN
NEARBY THROUGH THE WEEKEND HELP TO KEEP THE WINDS AND SEAS BELOW
ADVISORY CRITERIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ450>455.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...HAYES
SHORT TERM...RPW
LONG TERM...MEOLA
AVIATION...HAYES/MEOLA
MARINE...GORSE/MEOLA/RPW
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
320 AM CST WED FEB 1 2012
.SYNOPSIS...
EARLY AM SFC ANALYSIS PLACES LOW NORTH OF LAKE HURON JUST TO NORTH OF
SUDBURY ONTARIO. COLD FRONT TRAILS FROM THE LOW THROUGH CENTRAL IN
INTO NORTH TX. WEAK RIDGING EXTENDS FROM CENTRAL PLAINS INTO THE
UPPER MIDWEST. STRATUS WHICH FORMED OVER THE DAKOTAS INTO WESTERN MN
YSTDY CONTINUES TO EXPAND AND SURGE SOUTHEAST AIDED BY COLD
ADVECTION OVER EXISTING SNOWPACK NORTH AND MOIST BL FROM SNOW MELT.
LATEST 11-3.9 MICRON SATL IMAGERY SHOWS LEADING EDGE OF THE STRATUS
FROM KVTI TO KFEP MOVING SOUTHEAST AT AROUND 12 KTS. SOME FOG ALSO
OCCURRING WITH STRATUS... BUT VSBYS GENERALLY AT OR ABOVE 3SM ATTIM.
&&
.SHORT TERM...TODAY AND TONIGHT...
CLOUD TRENDS WITH IMPACT ON TEMPS... AND FOG POTENTIAL MAIN FCST
CONCERNS.
MOST MODELS STRUGGLING TO CAPTURE CURRENT STRATUS DECK... EXCEPT
FOR LATEST RUNS OF HRRR AND RUC BACKUP MODELS VIA ESRL. THESE
MODELS GENERALLY SUPPORT CONTINUED SOUTHEAST MOVEMENT THROUGH
DAYBREAK WITH MOST OF AREA NORTH OF HWY 34 BLANKETED BY THE STRATUS
BY MID AM. ONE CONCERN IS THAT RECENT SATL TRENDS SEEM TO SHOW THE
STRATUS CONTINUING TO SLOW... AND MAY BE DUE IN PART TO OUTRUNNING
THE SNOW FIELD AND MORE MOIST BL FROM SNOW MELT PAST 24 HRS NORTH OF
HWY 30. JUST WHERE LEADING EDGE OF STRATUS RESIDES BY MID AM
LIKELY TO BE IT FOR MOVEMENT AS STRENGTHENING SOLAR INSOLATION
LIKELY TO IMPEDE FURTHER PROGRESS. OF COURSE WHERE THIS ENDS UP WILL
BE HUGE FACTOR ON HIGH TEMPS. ANOTHER FACTOR IS EVOLUTION OF THE
EXISTING STRATUS THIS AFTN INTO TNGT AND WHETHER ANY CLEARING CAN
TAKE PLACE. LATEST HRRR AND RUC BACKUP MODELS DO SUPPORT DECREASE IN
STRATUS THIS AFTN... WITH HRRR SLIGHTLY SLOWER AND NOT UNTIL MID AFTN.
0412Z AMDAR ASCENT SOUNDING FROM KMSP SIMILAR TO 00Z MPX RAOB AND
SHOWS MOIST LAYER 500-1000 FT THICK... WITH MOISTURE LINGERING INTO
STRONG INVERSION AND NOT JUST BELOW IT. THIS IS A CONCERN AS IS FACT
THAT AREA WILL RESIDE IN WEAK SYNOPTIC SCALE FLOW... THUS MIXING WILL
BE LIMITED TO TAP DRY AIR ALOFT AND PROMOTE EROSION. THEREFORE
FAVOR SLOWER CLEARING TRENDS FROM HRRR... BUT ALSO MUST WONDER IF THE
STRATUS DOESNT DISSIPATE THIS AFTN WHAT WOULD PROMOTE EVACUATION TNGT.
SOME MODELS DO SHOW WARMING IN 925 MB LAYER TNGT AS FLOW IN THIS
LAYER BECOMES WESTERLY IN ASSOCIATION WITH CLIPPER TYPE SYSTEM PASSING
WELL NORTH INTO NORTHERN MN AND WI. THIS MAY BE ENOUGH TO CHEW AWAY AT
ANY RESIDUAL STRATUS... AND FOR NOW SKY COVER GRIDS EVOLVING TO MORE
OPTIMISTIC IN TIME. AS FOR TDY... WILL BE HEAVILY NOWCASTING CURRENT
STRATUS DECK AND USING HRRR AND RUC BACKUP MODELS FOR TRENDS. FOR NOW
WILL GO WITH IDEA OF STRATUS NEARING HWY 34 BY MID AM THEN LINGERING
INTO AFTN WITH SLOW EROSION THROUGH THIS EVE. ALL AREAS TDY WILL BE
COOLER... BUT TEMPS STILL ABOVE NORMAL. COOLEST READINGS BENEATH THE
STRATUS WHERE TEMPS COULD STRUGGLE TO 40 DEGS IF THEY HOLD ALL DAY.
OTRW... WARMEST READINGS SOUTH WHERE U40S TO L50S LOOK LIKELY WITH SOME
INCREASING HIGH CLOUDINESS. IN SHORT... AS CLOUDS GO... SO GO THE TEMPS.
WITH SOME UNCERTAINTY ON CLOUD TRENDS TNGT STAYED NEAR GUIDANCE BLEND
ON LOW TEMPS. FOG A POSSIBILITY TNGT WITH LIGHT BL FLOW AND LLVL MOISTURE
ESPECIALLY IN THOSE AREAS THAT SEE CLEARING LATE DAY INTO EARLY EVE.
IF STRATUS LINGERS WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG FORM ON
WESTERN EDGE. TOO UNCERTAIN THOUGH FOR ANY MENTION ATTIM BUT PASS ON THE
CONCERN TO DAY CREW. ..05..
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
DRY AND QUIET CONDITIONS WILL BE SEEN THURS/THURS NIGHT AS HIGH
PRESSURE MOVES ACROSS THE AREA. TEMPERATURES WILL CONTINUE TO
AVERAGE ABOVE NORMAL.
STARTING FRIDAY...THINGS BECOME MORE INTERESTING. DPROG/DT CONTINUES
TO SHOW A SUBTLE SLOWING OF THE RESPECTIVE MODEL SOLUTIONS. HIGH
PRESSURE FROM THE NORTHERN PLAINS INTO THE GREAT LAKES CONTINUES TO
TREND STRONGER INDICATING A DEEPER FETCH OF DRY EASTERLY FLOW. THE
MAJOR UNKNOWN IS THE ENERGY CURRENTLY ENTERING THE GULF OF ALASKA
AND HOW IT WILL KICK OUT THE CUT OFF LOW IN THE PLAINS. ALL MODELS
CONTINUE TO SHOW VARIABILITY WHICH IS TRACEABLE TO HOW THE
RESPECTIVE ENERGIES INTERACT WITH EACH OTHER.
SO...FRIDAY MORNING WILL BE DRY WITH INCREASING CLOUDS. ALL MODELS
SHOW STRONG FORCING AND LOW CONDENSATION PRESSURE DEFICITS FROM
MISSOURI INTO CENTRAL IOWA ALONG WITH A GOOD MOISTURE FEED. OVER THE
CWFA...ALL MODELS SHOW EASTERLY FLOW FROM THE SFC UP THROUGH 850MB.
THUS PRECIP WILL NOT BE FAR AWAY FROM THE FAR SOUTHWEST PART OF THE
CWFA BY MID DAY FRIDAY.
FRIDAY AFTERNOON...THE DEEP AND DRY EASTERLY FLOW CONTINUES ACROSS
THE CWFA. BY MID TO LATE AFTERNOON 850-700MB CONDENSATION PRESSURE
DEFICITS COLLAPSE OVER ROUGHLY THE SOUTHWEST QUARTER OF THE CWFA
WITH GOOD FORCING. THE MOISTURE FEED BEGINS MOVING INTO THE CWFA AS
WELL. THE HEAVY RAIN AND LIFT TOOLS SHOW THE STRONG CONVERGENCE IS
THERE BUT WEAKENING WITH TIME. THUS RAIN SHOULD DEVELOP/MOVE INTO
THE CWFA IN AN ARCING LINE FROM NORTHERN KEOKUK COUNTY TO ROUGHLY
THE HANCOCK/MCDONOUGH BORDER BY EARLY EVENING. THE HIGHEST POPS WILL
BE IN THE FAR SOUTHWEST CORNER OF THE CWFA.
THE FACT THAT THE OVERALL CONVERGENCE IS WEAKENING WITH TIME PER THE
LIFT AND HEAVY RAIN TOOLS INDICATES THAT ANY CONVECTION THAT IS
OCCURRING ACROSS MISSOURI WILL BE STRATIFYING OUT AS IT MOVES INTO
THE CWFA. THUS ONLY RAIN IS EXPECTED THROUGH SUNSET.
FRIDAY NIGHT...THE WAA AND MOISTURE FINALLY WINS OUT OVER THE DRY
AIR BUT THE IMMEDIATE HWY 20 CORRIDOR WILL LIKELY REMAIN DRY THROUGH
MIDNIGHT. THE DRY EASTERLY FLOW WILL ALLOW EVAPORATIVE COOLING TO
OCCUR ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD. THIS
EVAPORATIVE COOLING WILL LIKELY RESULT IN A RAIN/SNOW MIX THAT
CHANGES OVER TO ALL SNOW IN THE HWY 20 CORRIDOR WITH ANY
ACCUMULATIONS BEING ONE HALF INCH OR LESS. THE HWY 30 CORRIDOR DOWN
TO ALMOST I-80 WILL LIKELY SEE A RAIN/SNOW MIX THAT DEVELOPS DURING
THE NIGHT.
SATURDAY ON...
MODEL CONSENSUS HAS LIKELY POPS FROM THE I-80 CORRIDOR ON SOUTH WITH
CHC POPS NORTH WHICH ARE LIKELY ON THE LOW SIDE. A RAIN/SNOW MIX
SHOULD BE ONGOING WITH SUNRISE OVER ROUGHLY THE NORTHERN 40 PERCENT
OF THE CWFA WITH RAIN ELSEWHERE. ANY MIX SHOULD CHANGE OVER TO A
VERY COLD RAIN AS THE DAY PROGRESSES. DYNAMIC COOLING COULD KEEP A
MIX GOING IN THE FAR NORTHWEST PART OF THE CWFA.
THE CONSENSUS GIVES CHC POPS SATURDAY NIGHT WITH SCHC POPS ON SUNDAY
AS ENERGY UPSTREAM KICKS THE STORM SYSTEM INTO THE EASTERN GREAT
LAKES. SUNDAY NIGHT THROUGH NEXT TUESDAY THE MODEL CONSENSUS HAS DRY
CONDITIONS ACROSS THE AREA AS NORTHWEST FLOW ALOFT DEVELOPS.
TEMPERATURES SATURDAY THROUGH TUESDAY SHOULD CONTINUE TO AVERAGE
ABOVE NORMAL BUT WILL BE MUCH CLOSER TO NORMAL SUNDAY THROUGH
TUESDAY. ..08..
&&
.AVIATION...
STRATUS WITH IFR TO LIFR CIGS AND LIGHT FOG BLANKETING KDBQ AND FAST
APPROACHING KCID TERMINAL AT 09Z. THE STRATUS IS ADVANCING SE AT 12 KTS
BUT LATEST SATL LOOP SUGGEST SOME SLOWING... WHICH WILL MAKE LOW CLOUD
FCST FOR KMLI AND ESPECIALLY KBRL QUITE TRICKY. WHERE THE STRATUS ENDS
UP BY DAYBREAK OR SHORTLY THEREAFTER LIKELY TO BE END POINT WITH
INCREASING SUNSHINE HALTING PROGRESS. WILL CONTINUE TO MONITOR LOW CLOUD
TRENDS AND AMEND AS NEEDED. AMDAR SOUNDINGS AT KMSP SHOW CLOUDS
500-1000 FT THICK AND EXTENDS INTO STRONG INVERSION... THUS MAKING
CLEARING LOW CONFIDENCE FOR THIS AFTN AND TNGT. SOME WARMING AT 925 MB
BY TNGT MAY END UP CHEWING AWAY AT THE STRATUS. POTENTIAL FOR FOG TNGT
WHICH COULD BE DENSE IN SOME AREAS ESPECIALLY WHERE SKIES CLEAR LATE TDY
INTO EVE. WINDS NORTHWEST 5-10 KTS BECOMING LIGHT WEST TO SOUTHWEST BY TNGT.
..05..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
05/08
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1235 AM EST WED FEB 1 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL BRING SHOWERS TO THE AREA THROUGH THE
MORNING HOURS. HIGH PRESSURE WILL PROVIDE A DRY END TO THE WORK
WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AREA OF SHOWERS MOVING THROUGH THE SOUTHERN HALF OF THE REGION.
THESE SHOWERS ARE MOVING EASTWARD WITH A PRE-FRONTAL SHORTWAVE. THE
WAVE WILL SHIFT INTO C PA BEFORE DAWN, AS THE SFC FRONT REACHES MY
WESTERN COUNTIES. EXPECT ANOTHER LINE OF SHOWERS AFTER DAWN RIGHT
ALONG THE FRONT. BOUNDARY WILL CLEAR THE AREA BY EARLY AFTERNOON,
SO WILL HAVE THE HIGHEST POPS IN THE MORNING HOURS. WEAK CAA
BEHIND FRONT WILL BRING COOLER TEMPERATURES TODAY, BUT READINGS
WILL REMAIN ABOVE NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
FRONT WILL STALL OVER THE MID-ATLANTIC TONIGHT, AS SFC HIGH MOVES
OVER THE GREAT LAKES. A WEAK SFC WAVE WILL MOVE ALONG THE STALLED
FRONT TONIGHT AND COULD POSSIBLY BRING A FEW SHOWERS TO MY FAR
SOUTHEASTERN ZONES. ONCE THIS WAVE MOVES OFF THE EAST COAST, HIGH
PRESSURE WILL SETTLE IN OVER THE ENTIRE UPPER OHIO VALLEY.
TEMPERATURES FOR THE REMAINDER OF THE SHORT TERM WILL REMAIN A BIT
ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MORE SO THAN THE LAST FEW DAYS...THE DETERMINISTIC MODELS AND
ENSEMBLE MEANS HAVE BEGUN TO SUGGEST VERY SIMILAR SCENARIOS IN
EJECTION OF THE 500HPA LOW THROUGH THE CENTRAL U.S AND TOWARDS THE
REGION. THE MODELS THAT YESTERDAY SUGGESTED A NEARLY STATIONARY
CUTOFF LOW OVER THE EASTERN ROCKIES...HAVE SPED UP TO A CLOSER
GEFS/GFS SOLUTION THAT HAS BE PREVALENT FOR A FEW DAYS. THE SPLIT
FLOW CONTINUES TO MAKE SOME OF THE FORECAST VARIABLES DIFFICULT
HOWEVER...ESPECIALLY IN REGARDS TO TIMING AND LOCATION OF THE
SURFACE LOW AS IT CROSSES THE OHIO VALLEY.
CONTINUED TO FOLLOW CLOSELY TO HPC GUIDANCE, BUT TOOK THE MOST RECENT
RUNS OF THE GEFS...GFS...AND ECMWF INTO ACCOUNT. KEPT CHANCE POPS IN
THE FORECAST SATURDAY THROUGH SUNDAY AS THE LOW CROSSES. USED A
BLEND OF HPC AND TO A GREATER EXTENT MEX GUIDANCE THROUGH TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL CONTINUE THIS EVE BUT WL BE MARRED BY
INCREASING...AND LOWERING MID LVL CLDINESS AS STRNG...WARM...MOIST
ADVCTN CONTS IN ADVN OF STRNG LOW PRES MOVG ACRS THE NRN LAKES.
-SHRA ACTIVITY WL ALSO BE ON THE INCRS...BUT RESTRICTIONS ARE NOT
ANTICIPATED UNTIL THE LLVLS GET CLOSER TO SATURATION LTR TNGT. MVFR
IS CONFIDENTLY FORECAST IN THE POST MIDNGT PD...AND SHOULD DOMINATE
AREA TAFS UNTIL FRONTAL PASSAGE LTR ON WEDNESDAY MRNG.
ALSO OF CONCERN IS THE INCREASING INDICATIONS OF MORE LLWS AS
PROGGED VIA THE LATEST NAM AND RUC MDL SOUNDINGS. HAVE THUS ADDED
THIS POTENTIAL FOR THE EVE TAF ISSUANCES WITH NR 50 KTS FORECAST
ABOVE THE INVERSION LEVEL...I.E. ARND 2 KFT...AGAIN UNTIL FRONTAL
PASSAGE LTR ON WED MRNG.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
LATEST DETERMINISTIC MDL SOLNS INDICATE THAT LOW PRES MOVING ALNG
FRONTAL BOUNDARY SHOULD PASS SUFFICIENTLY SOUTH OF UPR OH VALLEY
TERMINALS TO PRECLUDE WIDESPREAD RESTRICTIONS ON WED NGT. SFC WND
WL SHIFT TO THE NW IN THE WAKE OF THAT SYS ON THURSDAY WITH COLD
ADVCTN SPAWNING SOME LAKE/UPSLOPE ENHANCED STRATOCUMULUS. VFR
CONDITIONS ARE EXPECTED TO RTN FRIDAY...BUT ANOTHER LOW MAY DEGRADE
CONDTIONS AGAIN FOR THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
103 AM EST WED FEB 1 2012
.SYNOPSIS...
MOISTURE INCREASES RAPIDLY IN THE OHIO VALLEY TONIGHT. WEAK COLD
FRONT WEDNESDAY WITH WAVE WEDNESDAY NIGHT. HIGH PRESSURE THURSDAY
NIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATED...
BUMPED THE POPS AHEAD JUST SLIGHTLY AS LINE WAS BARELY OUTRUNNING
THE FORECAST. OTHERWISE...GRIDS ARE IN GOOD SHAPE. WILL BE
WATCHING THE EVOLUTION OF THE SHOWERS BEHIND THIS INITIAL LINE.
PREVIOUS DISCUSSION...
TRACKING AN UPPER LVL WAVE AND S/W TROF AXIS...WELL AHEAD OF SFC
FRONT. MODELS IN GOOD AGREEMENT WITH TIMING AND FORCING WITH THIS.
AS OF 02Z...SEEING SHRA BREAK OUT ACROSS KY INTO CENTRAL OH WITH
HELP OF STRENGTHENING LLJ AND LIFT IN MID LVLS. USED A BLEND OF
CURRENT POP GRIDS WITH HRRR MDL REFLECTIVITY REMAINDER OF NIGHT.
THIS TRACKS BAND OF SHRA THRU CWA...WEAKENING ONCE TO MTNS
PREDAWN. GIVEN AMNT OF DRY AIR IN LLVLS...SOME OF THIS WILL HAVE A
HARD TIME REACHING SFC INITIALLY.
THERE IS SOME MDL DISCREPANCY ON EXTENT OF PROGRESS INTO CWA BY
BAROCLINIC ZONE WEDNESDAY. MAY END UP PARKING IN SE OH OR ALONG OH
RVR WITH SUBSEQUENT SFC WAVE TRAVERSING BOUNDARY WEDNESDAY NIGHT.
DEW POINTS ARE EXPECTED TO INCREASE QUICKLY 00Z TO 06Z IN OUR
OHIO VALLEY COUNTIES AS MOISTURE STREAKS NE...UP THE RIVER VALLEY.
AREAS OF LIGHT RAIN SHOWERS EXPECTED TO DEVELOP INTO SOUTHEAST
OHIO...NORTHEAST KENTUCKY THIS EVENING.
FORECAST PROBLEM...IS HOW FAR EAST AND SOUTH DO THESE SHOWERS GET
LATE TONIGHT AND ON WEDNESDAY...BEFORE THE WEAK WAVE AFFECTS US
WEDNESDAY EVENING.
TRIED TO SLIDE THE LIKELY POP FOR SHOWERS EAST THROUGH CENTRAL WV
05Z TO 09Z...THEN INTO THE CENTRAL MOUNTAINS BEFORE DAWN.
DO NOT HAVE THE SURFACE FRONT INTO SOUTHEAST OHIO UNTIL 18Z
WEDNESDAY THEN TRIED TO HOLD NORTH OF A HTS-CRW LINE AT 00Z. THIS
IS A BIT FURTHER NORTH THAN THE 12Z NAM. SO HAVE POPS DROPPING OFF
A BIT DURING THE MORNING...BEFORE INCREASING AGAIN OVER SOUTHERN
COUNTIES DURING THE AFTERNOON...MAINLY HTS-CRW-EKN ON
SOUTH.
TRIED TO STAY MUCH WARMER THAN 12Z GFS MOS TEMPERATURE MINIMUM
TEMPERATURE GUIDANCE TONIGHT...FIGURING ON INCREASING CLOUD COVER
THIS EVENING.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
MODELS CONTINUE TO STRUGGLE WITH AGREEING ON THE DETAILS OF THE
SYSTEM FOR WEDNESDAY NIGHT INTO THURSDAY. NAM HAS TRENDED MORE
TOWARD THE GFS...BUT THE GFS IS NOT TOTALLY CONSISTENT WITH PREVIOUS
RUNS. CANADIAN DOES NOT DEVELOP THE WAVE MUCH...EXITING IT FAIRLY
FAST. DUE TO ALL THE UNCERTAINTY...WILL STAY TOWARD THE MIDDLE
GROUND FOR NOW.
LOW LEVEL WINDS LOOK TO BE CALM THURSDAY NIGHT. MOS GUIDANCE LOOKS A
BIT HIGH FOR A DECENT RADIATION NIGHT...SO WENT ON THE LOW SIDE OF
GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LOTS OF UNCERTAINTY IN THE LONG TERM PERIOD WITH LITTLE MODEL
AGREEMENT. 12Z ECMWF...ALONG WITH ITS 00Z PREDECESSOR...KEEP THE
AREA IN THE NORTHERN BRANCH OF SPLIT FLOW ALOFT OVER THE AREA...THUS
KEEPING A LOW PRESSURE SYSTEM AND ITS ASSOCIATED MOISTURE TO THE
SOUTH AND WEST OF THE AREA OVER THE WEEKEND. CANADIAN AND GFS KEEP
THE AREA IN THE SOUTHERN BRANCH OF THE FLOW...WITH GFS A BIT MORE
AGGRESSIVE WITH THE PROGRESSION OF THE LOW AND MOISTURE INTO OUR
REGION. FOR NOW...FOLLOWED HPC GRAPHICS...WHICH BROAD BRUSH POPS
ACROSS THE AREA...HOWEVER...BEST CHANCE FOR PRECIPITATION AT THIS
POINT DOES APPEAR TO BE THE SOUTHERN ZONES.
DUE TO THE OVERALL UNCERTAINTY...KEPT THE EXTENDED UNSETTLED UNTIL
MID WEEK WHEN HIGH PRESSURE TRIES TO REESTABLISH ITSELF OVER THE
REGION...RESULTING IN DRIER WEATHER.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
LINE OF SHOWERS WORKING EASTWARD...BUT WILL DO LITTLE TO THE
RESTRICTIONS THIS MORNING. BRIEF MVFR POSSIBLE...BUT WILL COME IN
MORE EFFICIENTLY WITH THE 925-850MB MOISTURE JUST AHEAD OF THE
COLD FRONT AFTER 12Z AND LINGERING THROUGH THE DURATION OF THE TAF
PERIOD. GUSTS TO 20KTS OUR OF THE SOUTHWEST POSSIBLE IN THE
MOUNTAINS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: TIMING OF RAIN SHOWERS MAY VARY BEHIND THE
INITIAL LINE. MVFR ONSET MAY VARY A COUPLE HOURS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 02/01/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H M M H H H H H H M M
HTS CONSISTENCY M M M M H H H H H H M M
BKW CONSISTENCY H H H H H H H M M M M M
EKN CONSISTENCY H H H H M M M H M M M M
PKB CONSISTENCY M M L H H L L M M M M M
CKB CONSISTENCY H M M M L M M H H M M M
AFTER 06Z THURSDAY...
IFR POSSIBLE IN CEILINGS IN LOW LEVEL MOISTURE WEDNESDAY
NIGHT...LINGERING INTO THURSDAY MORNING IN THE MOUNTAINS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/SL/RPY
NEAR TERM...KTB/26
SHORT TERM...RPY
LONG TERM...SL
AVIATION...26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
443 AM EST WED FEB 1 2012
.SYNOPSIS...
UNSEASONABLY MILD TEMPERATURES WILL CONTINUE THROUGH THE
WEEK...BEFORE TRENDING BACK TOWARD NORMAL THIS WEEKEND. A WEAK
COLD FRONT WILL PUSH ACROSS TODAY...BRINGING LIGHT RAIN SHOWERS
FOR THE MORNING. A WEAK LOW PRESSURE AREA WILL SLIDE THROUGH THE
MID ATLANTIC STATES TONIGHT...BUT LITTLE OR NO RAIN WILL MAKE IT
NORTH OF THE MASON-DIXON LINE. HIGH PRESSURE WILL RIDGE IN FROM
THE UPPER GREAT LAKES LATE IN THE WEEK. ANOTHER WARM STORM IS
POSSIBLE LATE IN THE WEEKEND OR EARLY NEXT WEEK...BUT UNCERTAINTY
IS HIGH AS A REX BLOCK WILL DEVELOP OVER THE ROCKIES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT OVER LOWER MICHIGAN AND INDIANA WILL MOVE QUICKLY
THROUGH OHIO THIS MORNING AND THROUGH PENNSYLVANIA THIS AFTERNOON.
TWO STRIPES OF LIGHT RAIN SHOWERS EVIDENT ON THE RADAR THIS
MORNING WILL CONTINUE TO SLIDE EASTWARD...WITH THE EASTERN LIFT
WEAKENING VERY QUICKLY. HRRR HAS A GOOD PORTRAYAL OF THE
EVOLUTION OF THE PRECIP THESE LAST FEW HOURS...BUT NOW APPEARS TOO
SLOW IN MOVING THE PRECIP TO THE EAST. WILL HOLD SCT POPS FOR THE
MORNING IN THE EAST...BUT DOWNSLOPING WILL THEN KILL THE PRECIP
BACK CLOSER TO THE FRONT. THE FRONT WILL PASS WITH LITTLE FANFARE
DUE TO THE LOSS OF MOISTURE...MAINLY JUST A GUSTY WIND SHIFT. THE
FRONT WILL SETTLE ALONG A LATITUDE JUST SOUTH OF THE PA BORDER.
TEMPS ARE AGAIN A TOUGH CALL. ABOUT HALF OF THE AREA IN THE 60S
YESTERDAY...AND EARLY MORNING TEMPS ALREADY IN THE 40S...EXCEPT
FOR THE DEEP DARK VALLEY IN WILLIAMSPORT. CALM/LIGHT EASTERLY WIND
THERE INDICATIVE OF COLD AIR DAMMING. BUT AS YESTERDAY PLAYED
OUT...THE MIXING SHOULD EVENTUALLY GET DOWN THAT DEEP AS WELL.
WILL KEEP THE COOLEST MAXES IN THE NW WITH SCT SHRA THERE FOR MOST
OF THE MORNING AND PERHAPS INTO EARLY AFTN UNTIL FROPA...THEN CAA
KEEP THINGS STEADY OR BEGINNING TO FALL A LITTLE. THE REST OF THE
AREA COULD AGAIN TAKE A RUN AT THE M50S-60F. HAVE ONLY DRAWN IN
>60F TEMPS IN THE SERN THIRD OF THE AREA WHERE SKIES SHOULD BECOME
MOSTLY SUNNY THIS AFTERNOON AND DOWNSLOPE WILL HELP THE TEMPS IN
THEIR UNUSUAL CLIMB.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
SFC LOW WAY TO THE NORTH THIS MORNING WILL BE INTO NORTHERN NEW
ENGLAND BY LATE AFTN. THE FRONT WILL LAY OUT TO THE SOUTH OF THE
STATE TONIGHT...AND A SRN STREAM WAVE WILL ROLL UP FROM THE TN
VALLEY ALONG THE FRONT. THE PRECIP WILL HAVE A HARD TIME MAKING IT
NORTHWARD FROM THE GOMEX...AS THE LOW WILL BE CAUGHT IN A FAST
WRLY FLOW ALOFT. A GENERAL BUT ONLY SHORT FALL IN HEIGHTS WILL
HAPPEN AFTER THE LOW PASSES TO THE EAST. LOWS TONIGHT WILL DIP TO
THE M-U20S N AND L-M30S S. WILL CARRY JUST A SLIGHT CHC --RA IN
THE FAR SRN COS TONIGHT.
ALL EYES WILL BE JUST TO THE WEST OF THE CWA ON THURSDAY MORNING.
THE MORNING MAY BE RATHER CLOUDY OVER OUR WESTERN COUNTIES WITH
AN UPSLOPE FLOW INTO THE ALLEGHENIES. DAFFODILS ARE ALREADY
POPPING UP IN MY NEIGHBORS GARDEN DUE TO THE WARM AND WET SEASON
SO FAR. THUS...THE RODENT RUN WITH PERSISTENCE AND TURN A BLIND
EYE TO HIS SHADOW...OR HE MAY AND ARGUE THAT WINTER JUST HAS NOT
SHOWN UP YET AND GET A QUICK GLIMPSE.
IT IS A SAFE BET THAT IT WON/T STAY THIS WARM...BUT IT STILL LOOKS
WARM FOR THURSDAY. TEMPS WILL NOT BE AS LOFTY AS TUESDAY OR
TODAY...BUT WILL STILL BE 5 OR 6 DEGS ABOVE NORMALS AS THE MORNING
CLOUDS WILL DECREASE..ESPECIALLY IN THE EAST. THE CLEARING WILL
OCCUR AS THE LARGE DOME OF HIGH PRESSURE OVER CENTRAL CANADA NOSES
THROUGH THE UPPER GREAT LAKES AND INTO THE STATE. THURSDAY NIGHT
LOWS IN THE TEENS IN THE NORTH AND 20S IN THE S WILL STILL BE 4-6F
ABOVE NORMAL.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE STARTS OUT THE PERIOD IN
REASONABLY GOOD AGREEMENT...SHOWING AN EVOLVING REX BLOCK OVER THE
WEST-CENTRAL CONUS WITH CONFLUENT FLOW DOWNSTREAM IN THE
NORTHEAST. THE ECENS MEAN...AND THE GEFS MEAN TO A SLIGHTLY
LESSER EXTENT...HAVE SHOWN THE STRONGEST CONTINUITY OF THE
GUIDANCE OVER THE PAST SEVERAL MODEL CYCLES. THE MEANS CONTINUE TO
INDICATE THAT THE PRIMARY SYNOPTIC WAVE AFFECTING THE CONTIGUOUS
UNITED STATES WILL MARCH STEADILY ACROSS THE SOUTHERN
PLAINS...LOWER MISSISSIPPI AND TENNESSEE VALLEYS...AND SOUTHEAST
THROUGH THE WEEKEND..WITH HIGH PRESSURE LARGELY DOMINATING THE
WEATHER PATTERN IN THE NORTHEAST STATES. ALTHOUGH FORECASTER
CONFIDENCE HAS SLIGHTLY INCREASED GIVEN THE RELATIVE STABILITY IN
THE PATTERN NOTED IN THE ENSEMBLE DATA...WILL STILL LEAN HEAVILY
TOWARD A 50-50 GUIDANCE COMPROMISE/BLEND FOR SIGNIFICANT WEATHER
ELEMENTS THROUGHOUT THE EXTENDED PERIOD. MORNING PRELIMS WERE
NUDGED TOWARD THE LATER ARRIVING GMOS/HPC DATA.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
A FEW SHOWERS ACROSS THE SOUTH...STILL GOOD VISIBILITY AND
CIGS FOR THE MOST PART.
EARLIER DISCUSSION BELOW.
CLEARING SKIES WILL ALLOW FOR TEMPERATURES TO PLUMMET AND THE
INVERSION TO TAKE HOLD...CUTTING OFF THE GUSTY WINDS DUE TO STRONG
FLOW ALOFT.
THE LLWS WILL PERSIST AS THE JET WILL BE AROUND 2000-4000 FT
AROUND 40-50 KTS THROUGH 15Z. MID LEVEL CLOUDS WILL BEGIN TO CREEP
IN FROM THE WEST BEFORE LOW PRESSURE SYSTEM AND THE ASSOCIATED
WEAK COLD FRONT SHOULD SLIDE BY TO OUR NORTH. LIGHT SHOWERS WILL
MOVE IN AFTER 06Z...WITH HIGHEST POPS IN THE NW MTNS TAPERING BACK
TO SCATTERED IN THE CENTRAL AND EAST. MVFR DEVELOPS AT KBFD LATE
TONIGHT...AND COULD SPREAD INTO CENTRAL MTNS BRIEFLY AROUND 12Z.
SHOWERS SHOULD CEASE 15 TO 18Z AS THE FRONT ELONGATES AND EXITS
EARLY TOMORROW AFTERNOON...WHICH SHOULD ALLOW CIGS/VSBY TO IMPROVE
TO VFR AREA-WIDE.
OUTLOOK...
THU...AM FOG POSSIBLE...ESP W MTNS.
FRI-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...CERU/MARTIN/RXR
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
327 AM CST WED FEB 1 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
WEAK COLD AIR ADVECTION STRATUS HAS SETTLED OVER SRN WI DURING
THE NIGHT. TAMDAR ASCENT SOUNDINGS FROM KMSP CONFIRM 00Z KMPX
SOUNDING SHOWING CLOUDS ABOUT 500-1000FT THICK...WITH SOME OF THE
MOISTURE IN AS WELL AS BELOW THE SUBSIDENCE INVERSION WITH DRIER
AIR ALOFT. UPSTREAM LOW LEVEL FLOW WEAK VCNTY OF LOW LEVEL RIDGING
AND BACK EDGE OF LOW CLOUDS IN WRN MN NOT MAKING MUCH EWD PROGRESS
LAST FEW HOURS. 06Z NAM TRIES TO BREAK UP/THIN RH LATER THIS MRNG
OVER PORTIONS OF SRN WI WHILE RUC IS LESS OPTIMISTIC.
NOT SEEING MUCH SUBSIDENCE ALOFT ASSOCD WITH ANY SYNOPTIC FEATURE
TO HELP SCOUR LOW CLOUDS...AND WEAK UPSTREAM SHORT WAVE OVER ERN
DAKOTAS DOES BRING IN MID/HIGH CLOUDS LATER TODAY. WITH WEAK COLD
AIR ADVECTION CONTINUING THIS MRNG AND LIGHTER FLOW IN THE LOW
LEVELS SETTLING IN...WL BE MORE PESSIMISTIC WITH CLOUDS FOR TODAY.
SECOND SLIGHTLY STRONGER MID-LEVEL WAVE WL BRING MORE MID/HIGH
CLOUDS INTO THE AREA TONIGHT...AND VERY POSSIBLE THAT LOW CLOUDS
WILL STILL BE HANGING AROUND SRN WI.
HWVR...WL NEED TO WATCH FOR WEAK TERRAIN INDUCED SUBSIDENCE
HELPING TO THIN THE CLOUDS IN THE FAR ERN CWA LATER THIS MRNG AND
AFTN. NEVER THE LESS...WITH CLOUDY TO M/CLOUDY CONDITIONS EXPCD
TODAY AND W-NW SFC WNDS...KEPT TEMPS IN CHECK...CLOSER TO COOLER
MET GUIDANCE. DESPITE EXPCD CLOUD COVER TONIGHT...LIGHT BOUNDARY
LAYER WINDS SHOULD ALLOW AT LEAST PATCHY FOG TO DEVELOP.
.SHORT TERM...THURSDAY THROUGH FRIDAY NIGHT...FORECAST CONFIDENCE
MEDIUM TO HIGH.
WEAK HIGH PRESSURE WILL SLOWLY MOVE EAST ACROSS THE REGION
THURSDAY AND THURSDAY NIGHT...BRINGING QUIET WEATHER TO THE AREA.
SOME MIDDLE OR HIGH CLOUDS MAY MOVE THROUGH THE AREA AT TIMES.
LIGHT WINDS AND LOW LEVEL MOISTURE THURSDAY NIGHT MAY LEAD TO SOME
FOG FORMATION...BUT MODELS HAVE BEEN OVERESTIMATING LOW LEVEL
MOISTURE QUITE A BIT THIS WINTER...SO WILL NOT MENTION IN FORECAST
YET. MILD TEMPERATURES WILL CONTINUE...WELL ABOVE SEASONAL
NORMALS.
LARGER HIGH PRESSURE ACROSS THE FAR NORTHERN PLAINS FRIDAY WILL
KEEP THE AREA DRY...WITH ANOTHER MILD DAY EXPECTED UNDER PARTLY
SUNNY SKIES.
LEE CYCLOGENESIS OCCURS IN THE SOUTHERN HIGH PLAINS THURSDAY NIGHT
INTO FRIDAY...AS AN UPPER LOW DEVELOPS ACROSS THE SOUTHERN ROCKIES
AND SHIFTS INTO THE SOUTHERN HIGH PLAINS. THE NAM/GFS/CANADIAN
MODELS ARE QUICKER WITH THE PROGRESSION OF THIS SYSTEM TO THE EAST
ACROSS THE CENTRAL PLAINS THAN THE ECMWF. THE ECMWF DEVELOPS A
DEEP CUTOFF LOW OVER NORTH CENTRAL KANSAS BY 12Z SATURDAY...WITH A
DEEP SURFACE LOW JUST TO THE EAST.
THE OTHER MODELS HAVE THE UPPER LOW ANYWHERE FROM SOUTH CENTRAL
KANSAS TO FAR SOUTHWEST IOWA...WITH THE SURFACE LOW ANYWHERE FROM
NORTHERN TO SOUTHWESTERN MISSOURI. GIVEN THE CONFIDENCE HPC HAS
HAD WITH THE ECMWF AND ECMWF ENSEMBLES WITH THIS SYSTEM...LEANED
TOWARDS IT AND KEPT MOST OF THE AREA DRY FRIDAY NIGHT. KEPT LOW
POPS IN THE FAR SOUTHWEST LATE FRIDAY NIGHT FOR CONTINUITY...BUT
MAY HAVE TO TAKE THESE OUT IN LATER FORECASTS IF SLOWER ECMWF
VERIFIES.
.LONG TERM...SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE LOW.
MAJOR DIFFERENCES EXIST DURING THIS PERIOD BETWEEN THE ECMWF AND
GFS. THE GFS CONTINUES TO BE MORE PROGRESSIVE WITH THE UPPER LOW
SATURDAY INTO SATURDAY NIGHT...TAKING IT ACROSS SOUTHERN IOWA AND
CENTRAL ILLINOIS. ASSOCIATED SURFACE LOW MOVES QUICKLY EAST FROM
CENTRAL MISSOURI TO KENTUCKY. THIS TRACK BRINGS PRECIPITATION INTO
THE AREA SATURDAY INTO SATURDAY EVENING.
THE ECMWF REMAINS SLOWER AND DEEPER WITH THE UPPER LOW DURING THIS
TIME...KEEPING IT ACROSS THE CENTRAL PLAINS. SURFACE LOW OCCLUDES
AS IT BECOMES VERTICALLY STACKED WITH THE UPPER LOW. THIS SCENARIO
ALSO BRINGS LIGHT PRECIPITATION INTO MAINLY SOUTHERN PORTIONS OF
THE AREA. WILL CONTINUE TO USE CONSENSUS POPS AND TEMPERATURES FOR
THIS PERIOD...THOUGH WOULD LEAN MORE TOWARD THE SLOWER LOOK OF THE
ECMWF.
ECMWF TAKES UPPER LOW AND DEVELOPS AN OPEN WAVE OUT OF IT SUNDAY
NIGHT THROUGH MONDAY AS IT MOVES EAST THROUGH THE REGION. IT DOES
BRING LIGHT PRECIPITATION ACROSS THE AREA WITH IT. THE GFS IS DRY
WITH HIGH PRESSURE ACROSS THE AREA DURING THIS TIME. THEY BOTH
GENERALLY SHOW SOME COLD AIR ADVECTION LATER MONDAY INTO
TUESDAY...WITH THE ECMWF SHOWING STRONG COLD AIR ADVECTION TUESDAY
WITH A SHARP UPPER TROUGH MOVING THROUGH THE REGION. THE GFS IS
MUCH WEAKER WITH THE COLD ADVECTION. WILL CONTINUE TO USE
CONSENSUS POPS AND TEMPERATURES DURING THIS TIME. MILD
TEMPERATURES SHOULD CONTINUE DESPITE THE MODEL DIFFERENCES.
&&
.AVIATION/12Z TAFS/...
MVFR CIGS HAVE ENGULFED ALL OF SRN WI EARLY THIS MRNG. WILL
CONTINUE MVFR CIGS INTO THE AFTN...WITH LIGHTER WINDS IN WRN CWA
POSSIBLY ALLOWING CIGS TO FALL INTO IFR CATEGORY FOR A TIME AT
KMSN. FOR NOW WL TREND TOWARD CLOUDS THINNING THIS AFTN...BUT
CONFIDENCE LOW DUE TO ABOVE DISCUSSION. LIGHTER BOUNDARY LAYER
WINDS AND LINGERING LOW LEVEL MOISTURE SHOULD ALLOW PATCHY FOG TO
DEVELOP TONIGHT.
&&
.MARINE...
NORTHWEST WINDS WILL CONTINUE TO DIMINISH THIS MORNING AS THE
PRESSURE GRADIENT FURTHER WEAKENS. LIGHT WIND CONDITIONS ARE THEN
EXPECTED FOR AN EXTENDED PERIOD OF TIME FROM TONIGHT THROUGH
FRIDAY...UNTIL LOW PRESSURE BEGINS TO STRENGTHEN OVER THE CENTRAL
PLAINS AND MEANDER EWD OVER THE WEEKEND.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
THURSDAY THROUGH TUESDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 PM CST TUE JAN 31 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY
244 PM CST TUE JAN 31 2012
MAIN FORECAST CONCERNS ARE CLOUDS AND TEMPERATURES THROUGH FORECAST
PERIOD.
LATEST WATER VAPOR SATELLITE IMAGERY INDICATING WEAK SHORTWAVE
TROUGHS EMBEDDED IN WEST TO EAST ZONAL FLOW ACROSS THE CONTINENTAL
UNITED STATES. ONE SHORTWAVE TROUGH OVER THE UPPER MIDWEST IS
PRODUCING LOW STRATUS DECK OF CLOUDS ACROSS MUCH OF NORTHERN AND
CENTRAL MINNESOTA.
THE DETERMINISTIC 31.12Z NAM AND GFS INITIALIZED OVERALL UPPER LEVEL
PATTERN WELL PER LATEST UPPER AIR ANALYSIS. MAIN DIFFERENCE BETWEEN
THE DETERMINISTIC 31.12Z GFS AND NAM IS THE 31.12Z GFS SLIGHTLY
MORE ROBUST WITH WEAK SHORTWAVE TROUGH MOVING ACROSS THE UPPER GREAT
LAKES REGION WEDNESDAY NIGHT. OTHERWISE..THE DETERMINISTIC 31.12Z
GFS/NAM ARE IN DECENT AGREEMENT WITH SURFACE AND UPPER LEVEL FEATURES
THROUGH FORECAST PERIOD.
TONIGHT AND WEDNESDAY..LOW STRATUS DECK OF CLOUDS WILL CONTINUE TO
ADVANCE SOUTHEASTWARD INTO THE FORECAST AREA. BIG QUESTION WILL BE
HOW FAR SOUTH THE LOW STRATUS DECK ADVANCES. THE 31.12Z GFS AND
NAM DOES SHOW THE WESTERN EDGE OF STRATUS DECK TO ERODE AS THE LOW
CLOUDS ADVANCE INTO THE FORECAST AREA. FOR NOW HAVE INCREASED SKY
CONDITION ACROSS MUCH OF THE FORECAST AREA AFTER 00Z WEDNESDAY.
WITH REGION REMAINING UNDER CYCLONIC FLOW AND NEXT WEAK IMPULSE
TRACKS INTO THE UPPER GREAT LAKES REGION...LOW STRATUS DECK OF CLOUDS
IS EXPECTED TO REMAIN OVER THE NORTHEASTERN HALF OF THE FORECAST AREA
THROUGH WEDNESDAY NIGHT. THE 31.12Z GFS DOES INDICATE WEAK
LIFT/FORCING IN ASSOCIATION WITH THE WEAK IMPULSE AND PRODUCES SOME
LIGHT PRECIPITATION OVER NORTH CENTRAL WISCONSIN. AT THIS TIME...
WITH WEAK LIFT AND MINIMAL FORCING WILL CONTINUE WITH DRY
CONDITIONS ACROSS FORECAST AREA.
NEXT CONCERN IS BOTH THE 31.12Z GFS AND NAM CUTOFF UPPER LEVEL LOW
OVER THE SOUTHERN AND CENTRAL PLAINS AND LIFT UPPER LEVEL LOW INTO
CENTRAL KANSAS THURSDAY NIGHT INTO FRIDAY. BOTH THE 31.12Z GFS AND
NAM SHOW THE BEST ISENTROPIC LIFT AT 290K SURFACE TO BE SOUTH OF
FORECAST AREA. HAVE PUSHED PRECIPITATION CHANCES SOUTH AND
WEST OF FORECAST AREA THURSDAY NIGHT AND FRIDAY.
.LONG TERM...FRIDAY NIGHT TUESDAY
244 PM CST TUE JAN 31 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES FRIDAY NIGHT
INTO SUNDAY. THE DETERMINISTIC 31.12Z GFS/GEM/ECMWF ARE IN DECENT
AGREEMENT IN CUTTING OFF UPPER LEVEL LOW OVER THE SOUTHERN AND
CENTRAL PLAINS FRIDAY NIGHT AND SATURDAY. HOWEVER...THE DETERMINISTIC
MODELS ARE IN DISAGREEMENT IN LIFTING UPPER LEVEL LOW INTO THE UPPER
MIDWEST AND GREAT LAKES REGION AFTER 18Z SATURDAY. CONFIDENCE IN
PRECIPITATION CHANCES ARE LOW FRIDAY NIGHT INTO SATURDAY...DUE TO
HIGH VARIABILITY IN LIFTING/MOVING CUTOFF LOW INTO THE UPPER
MIDWEST. TEMPERATURES THROUGH FORECAST PERIOD WILL REMAIN ABOVE
NORMAL...AS UPPER LEVEL CUTOFF LOW ADVECTS WARMER AIR NORTHWARD INTO
THE UPPER MIDWEST.
&&
.AVIATION...THROUGH 06Z THURSDAY
1143 PM CST TUE JAN 31 2012
A LARGE STRATUS DECK WAS OVER THE TAF SITES LATE THIS EVENING.
IFR/LIFR CEILINGS WERE FOUND OVER MUCH OF MINNESOTA...WITH LOWER
MVFR CEILINGS AT KLSE. INFRARED SATELLITE IMAGERY WAS SHOWING BACK
EDGE OF THE STRATUS EXTENDING FROM KAQP TO KFRM WITH THE DISTANCE
SPEED TOOL INDICATING THIS BACK EDGE WAS MOVING EASTWARD AROUND 9
KNOTS. MODELS CONTINUE TO SHOW LIFR TO IFR CEILINGS AT KRST AND
LOWER MVFR CEILINGS AT KLSE THROUGH 14Z. FROM 14Z ON...MODELS
DIVERGE IN MOVING THE STRATUS OUT...WITH THE 02.00Z RUC KEEPING
MOISTURE TRAPPED UNDER THE INVERSION INTO THE AFTERNOON
HOURS...WHILE THE NAM SHOWS CLEARING THROUGH THE MORNING HOURS.
BASED ON LINEAR MOTION OF THE BACK EDGE...DID TRY AND TIME THE
STRATUS OUT OF THE TAF SITES...CLEARING KRST 13Z-14Z AND KLSE
AROUND 16Z-17Z. BUT CONFIDENCE NOT HIGH ON THIS SCENARIO. ONCE THE
STRATUS CLEARS...LOOK FOR JUST SCATTERED MID AND HIGH LEVEL CLOUDS
THROUGH 06Z THURSDAY. WITH THE MELTING SNOW...COULD SEE
VISIBILITIES DROP INTO THE 3-5SM RANGE BETWEEN 04Z-06Z THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
244 PM CST TUE JAN 31 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1051 PM CST TUE JAN 31 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT THROUGH WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A MOISTURE
STARVED LOW PRESSURE SYSTEM MOVING OVER THE CENTRAL UPPER PENINSULA
EARLY THIS AFTERNOON...AND ITS ASSOCIATED COOL FRONT PUSHING ACROSS
CENTRAL WISCONSIN. THE COLDER AIR IS LAGGING BEHIND THE FRONT AND
CAN BE MARKED BY THE LEADING EDGE OF A LOW STRATUS DECK THAT IS
SHIFTING SE OVER MINNESOTA AND ALMOST TO THE WI BORDER. DESPITE THE
SHALLOW NATURE OF THE LOW MOISTURE ON 12Z RAOBS...MIXING HAS NOT
DETERRED ITS PROGRESS SO FAR TODAY. WILL MAKE SOME LAST MINUTE
ADJUSTMENTS TO SPEED UP ITS FORWARD MOTION IF THIS CONTINUES TO BE
THE CASE. AS THESE CLOUDS ADVANCE TOWARDS NORTHERN
WISCONSIN...CLOUDS AND TEMPS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...LOW PRESSURE WILL CONTINUE TO TRACK TO THE EAST OVER THE
EASTERN UPPER PENINSULA INTO SOUTHEAST ONTARIO. MID AND HIGH CLOUDS
WILL DEPART THIS EVENING WITH THE ELONGATED SHORTWAVE TROUGH...BUT
PLENTY OF LOW CLOUDS UPSTREAM WILL SHIFT SE WITHIN A COOLER AIRMASS
WRAPPING AROUND THE LOW AND INTO THE NORTHERN HALF OF THE STATE.
ALTHOUGH THE MOISTURE IS SHALLOW AND SOME EROSION IS EXPECTED...THE
COOLER AIRMASS WILL PROMOTE ITS ADVANCEMENT ACROSS NORTH-CENTRAL AND
CENTRAL WISCONSIN TONIGHT. THINK DOWNSLOPING SHOULD PREVENT THE
STRATUS FROM MAKING IT INTO THE FOX VALLEY AND NORTHEAST
WISCONSIN...SO HAVE KEPT PARTLY CLOUDY WORDING THERE. NO REAL
CHANCE OF DECOUPLING TONIGHT...SO LOWS WILL BE MILD AND RANGE FROM
THE LOWER 20S NORTH TO AROUND 30 SOUTHEAST.
WEDNESDAY...STRATUS WILL LIKELY HANG AROUND FOR MUCH OF THE MORNING
OVER NORTHERN WISCONSIN THOUGH SOME EROSION IS LIKELY OVER CENTRAL
WISCONSIN WITH DAYTIME HEATING. THE COOLER AIRMASS WILL CONTINUE TO
MODERATE THROUGH THE AFTERNOON SO EXPECTING CLOUDS TO RETREAT TO THE
NORTH OR NORTHEAST THROUGH THE DAY. ALSO IN THE AFTERNOON...THE
NEXT SHORTWAVE TROUGH WILL MOVE INTO WESTERN WISCONSIN. MID-LEVELS
HAVE A DRY WEDGE SO NO REAL THREAT OF PRECIP. HIGHS WILL BE COOLER
THAN TODAY...AND WILL GO WITH MID TO UPPER 30S.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. SOUNDS LIKE A
BROKEN RECORD...BUT MORE MILD AND DRY WEATHER EXPECTED FOR THE
NEXT WEEK OR SO. THE SPLIT FLOW PATTER WILL CONTINUE WITH WEAK
SHORTWAVE TROUGHS MOVING BY TO THE NORTH THROUGH WITH LITTLE
MOISTURE WHILE MORE SIGNIFICANT SYSTEMS IN THE SOUTHERN STREAM STAY
TO OUR SOUTH. ANY PHASING THAT TAKES PLACE IS WELL TO OUR EAST.
THE BEST CHANCE OF ANY PRECIPITATION LOOKS TO BE SUNDAY OR SUNDAY
NIGHT AS SYSTEM IN THE SOUTHERN STREAM PASSES BY TO THE SOUTH. IT
MAY CLIP CENTRAL AND NORTHERN WISCONSIN WITH SOME LIGHT SNOW OR
RAIN BUT THAT/S ABOUT IT.
&&
.AVIATION...
LARGE AREA OF MVFR/IFR CIGS MOVING EAST THROUGH WI. MODELS SUGGEST
CLOUDS REMAINING OVER AREA THROUGH THE NIGHT...BREAKING UP BY MID
DAY WED. DOWNSLOPING...DUE TO WEST TO NORTHWEST WINDS EXPECTED TO
KEEP CIGS SCT TO BKN MVFR OVER FOX VALLEY AND NE WISCONSIN
(THROUGH OVERNIGHT HOURS). WEAK UPPER DISTURBANCE TO MOVE THROUGH
OVERNIGHT WED...WITH RETURN OF MAINLY MID AND HIGH CLOUDS...THOUGH
SOME MODELS INDICATE LOW CLOUDS TO RETURN TO NORTH-CENTRAL
LOCATIONS.
TE
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1047 AM EST WED FEB 1 2012
.UPDATE...
LARGE AREA OF STRATUS OVER THE UPR GRTLKS CONTG TO SAG SEWD ACROSS
OUR CWA THIS MORNING. USING RUC 925MB RH FIELDS AND LATEST VISIBLE
SATELLITE IMAGERY EXPECT THIS CLOUD DECK WILL IMPACT OUR ENTIRE CWA
THIS AFTN... THUS UPDATED FCST TO INCREASE CORRESPONDING CLOUD COVER GRIDS.
STRATUS SHOULD HOLD TEMPS DOWN A BIT THIS AFTN AND LOWERED HIGHS
SLIGHTLY MOST OF THE CWA. CLOUDS COULD LIMIT COOLING TONIGHT AS
WELL BUT HELD OFF MAKING ANY CHANGES IN THAT REGARD ATTM.
&&
.PREV DISCUSSION... /ISSUED 640 AM EST WED FEB 1 2012/
AVIATION.../12Z TAFS/
AN AREA OF MVFR CIGS OVER LAKE MICHIGAN WILL MOVE INTO KSBN SHORTLY
AFTER TAF ISSUANCE. A FEW POCKETS OF MVFR STRATUS HAVE DEVELOPED
AHEAD OF THE MAIN AREA AND MAY IMPACT KFWA EARLY THIS MORNING.
OTHERWISE...KFWA STILL LOOKS TO REMAIN ON SOUTHERN FRINGE OF MAIN
CLOUD DECK. VFR CONDITIONS EXPECTED ALL PLACES BY AFTERNOON.
SHORT TERM...
TODAY THROUGH THURSDAY NIGHT
SFC COLD FRONT AND THE ASSOCIATED MID LEVEL IMPULSE WILL CONTINUE TO
EXIT THE REGION WITH COOLER AIR ADVECTING INTO THE REGION. FAIRLY
QUIET WEATHER IN THE PERIOD...WITH CONTINUED PROGRESSIVE FLOW AND A
DEVELOPING SPLIT PER A DIGGING SW CONUS TROUGH. ANOTHER FAST MOVING
NORTHERN STREAM WAVE EXPECTED INTO THE GREAT LAKES TONIGHT...WITH
WEAK RIDGING AT THE SFC. MILD THERMAL FIELDS PER PAC ORIGIN FLOW
WILL SUPPORT TEMPS ABOVE NORMAL IN THE PERIOD...WITH COOLER
CONDITIONS TODAY ON THE BACKSIDE OF THE DEPARTING IMPULSE. MAIN
CONCERN TODAY WILL BE HIGH TEMPS ACROSS THE NORTHERN THIRD AS
BACKSIDE IMPULSE STRATUS GRAZES THE AREA. GENERAL CONSENSUS IN
GUIDANCE IS FOR THE BULK OF THE CLOUDS TO REMAIN NORTH OF THE
FA...WITH THE NORTHERN THIRD BEING GRAZED THIS MORNING. DIURNAL
MIXING SHOULD SUPPORT SCATTERING OF THE STRATO CU DECK BY LATE
MORNING/EARLY AFTERNOON. HIGHS WILL BE COOLER THAN YESTERDAY...WITH
MOST AREAS ONLY SEEING 40S...SOME LOWER 50S POSSIBLE FAR SOUTH.
NORTHERN PLAINS IMPULSE /EVIDENT IN WATER VAPOR/ WILL ADVECT INTO
THE GREAT LAKES OVERNIGHT...SUPPORTING INCREASED MID/HIGH CLOUD.
OVERALL WEAK FORCING WITH LIMITED LL MOISTURE WILL SUPPORT LIGHT LL
FLOW...WITH DRY CONDITIONS OVERNIGHT. INCREASED CLOUD COVER WILL
KEEP TEMPS UP SOME...WITH LOWER 30S TO UPPER 20S EXPECTED. SMALL
THERMAL FIELD UNDULATION ASSOCIATED WITH THIS WAVE WILL SUPPORT A
REINFORCEMENT OF THERMAL FIELDS WITH HIGHS GENERALLY AROUND TODAY/S
VALUES...SLIGHTLY WARMER SW HALF GIVEN ENSUING WAA BY LATER IN THE
DAY PERIOD THUR. MOSTLY CLEAR SKIES AND LIGHT WINDS EXPECTED THUR
NIGHT...WITH MODERATE RADIATIONAL COOLING SUPPORTING LOWS IN THE
UPPER 20S MOST PLACES. A FEW HEIGHT RISE CIRRUS ARE POSSIBLE.
LONG TERM...
COMPLICATED AND VARIABLE LONG TERM FORECAST AS MODELS REMAIN IN FLUX
WITH HANDLING WEEKEND SYSTEM OVER CENTRAL CONUS. PREFERENCE AT THIS
TIME LIES TOWARD THE ECMWF WITH STRONG WEIGHT TOWARD CONSISTENCY AS
DETAILS AND EVEN LARGER SCALE FLOW STILL IN QUESTION WITH UPCOMING
SYSTEM. WHAT DOES LOOK MORE CERTAIN ARE TEMPERATURES THROUGH MOST OF
THIS LONG TERM PERIOD REMAINING ABOVE NORMAL. THERE ARE SIGNS
POINTING TOWARD COLDER...MORE SEASONABLE TEMPERATURES JUST BEYOND
THE DAY 7 PERIOD.
WATER VAPOR TELLS THE STORY TODAY WITH STRONG NORTH PACIFIC JET AND
SEVERAL STRONG SHORT WAVES BEGINNING TO BUCKLE THE FLOW OVER THE
NORTH PACIFIC. PNA TELECONNECTIONS SHOW TREND TOWARD POSITIVE PHASE
FROM 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL WITH GOOD CORRELATION
THROUGH THE 7 TO 10 DAY FORECAST PERIOD. AO INDICES ALSO TRENDING
STRONGLY NEGATIVE SUPPORTING GREATER AMPLIFICATION OF UPSTREAM
PATTERN AND POTENTIAL COLDER TEMPERATURES MID TO END OF NEXT WEEK.
THESE FACTORS SHOULD ALLOW FOR STRONG RIDGE TO DEVELOP IN WESTERN
CONUS WHICH WOULD ALSO ALLOW INCOMING ENERGY TO DEEPEN ACROSS THE
PLAINS BY END OF THIS WEEK. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON
THIS SCENARIO THROUGH FRIDAY WITH CLOSED LOW DEVELOPING IN CENTRAL
CONUS. MODELS REALLY BEGIN TO DIVERGE THIS WEEKEND WITH HOW THIS LOW
WILL EVOLVE AND EVENTUALLY EJECT OUT OF CENTRAL CONUS AND THE
ASSOCIATED IMPACTS AND TIMING FOR OUR AREA. DIFFERENCES APPEAR TO BE
RELATED TO TIMING OF A NORTHERN STREAM SHORT WAVE AND LOCATION OF
UPPER LOW BY END OF WEEKEND. GFS AS EXPECTED IS FARTHER EAST WITH
UPPER LOW AND ALLOWS NORTHERN WAVE TO PICK UP CLOSED LOW AND BOTH
EJECT SOUTHEAST OUT OF THE AREA SUNDAY NIGHT. MEANWHILE...ECMWF
SOLUTION APPEARS TO BE SLOWER WITH UPPER LOW DRIFTING EAST AND
ALLOWS NORTHERN STREAM WAVE TO PASS THROUGH GREAT LAKES LEAVING
BEHIND THE LOW IN THE PLAINS TO CONTINUE WITH A SLOWER MOVEMENT
NORTHEAST. GIVEN TYPICAL GFS BIAS WITH BEING TOO FAR EAST WITH
CLOSED UPPER LOWS AND ECMWF SUPERIOR PERFORMANCE DURING THE WINTER
PREFERENCE LIES TOWARD THE ECMWF. HOWEVER...FOR CONSISTENCY AND TO
AVOID FLIP FLOPPING FORECAST DUE TO HIGH UNCERTAINTY...HAVE REMAINED
FAIRLY CLOSE TO ALL BLEND INIT FOR THIS PACKAGE. THIS REFLECTS BEST
CHANCES FOR PCPN LATE FRIDAY NIGHT AND SATURDAY IN SOUTH AS INITIAL
SURGE OF MOISTURE AND WEAK SHORT WAVE APPROACH THE AREA. LOW CHANCE
POPS CONTINUED THROUGH SUNDAY WITH ECMWF SHOWING WEAK LIFT AND
MOISTURE FOR POSSIBLE SHOWERS. REMAINDER OF FORECAST WAS LEFT
UNCHANGED WITH NO APPRECIABLE WEATHER MENTION GIVEN HIGH UNCERTAINTY
AND LOW PROBABILITY AT THIS TIME.
REGARDLESS OF SOLUTIONS TEMPERATURES WILL REMAIN ABOVE NORMAL
THROUGH MOST OF THE PERIOD...AND WELL ABOVE NORMAL THROUGH THIS
WEEKEND. TEMPERATURES LIKELY TO TREND BACK CLOSER TO NORMAL BY DAY 7
WITH ECMWF SOLUTION. MUCH COLDER AIR LOOKS TO STAGE TO OUR NORTH BY
DAY 7 WITH POSSIBILITY OF REACHING US BY MID TO LATE NEXT WEEK.
TELECONNECTION INDICES FAVORING THIS BUT NORTH ATLANTIC OSCILLATION
FORECAST CONTINUES TO BE NEAR NEUTRAL THROUGH THE WEEK 2 PERIOD
SUGGESTING NO BLOCKING DOWNSTREAM TO HOLD COLD AIR IN PLACE. THIS IS
WELL OUTSIDE THE CURRENT FORECAST PERIOD BUT SOMETHING TO WATCH
GIVEN POSITIVE PNA AND NEGATIVE AO TRENDS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...LASHLEY
AVIATION...JC
UPDATE...TAYLOR
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
608 AM CST WED FEB 1 2012
.UPDATE...
STRATUS AND FOG CONTINUES TO ADVECT IN ON LLVL NORTHWEST FLOW. SEVERAL
SITES HAVE GONE DOWN AT OR BELOW 1/4SM ESPECIALLY ON THE IA SIDE
OF RIVER ALONG/N OF I-80. HAVE THEREFORE ISSUED DENSE FOG ADVISORY FOR
THIS AREA UNTIL 16Z. GIVEN STRENGTH OF INVERSION AND STRATUS COULD SEE
DENSE FOG PERSIST INTO THE AFTN.
&&
.AVIATION...
STRATUS AND FOG WITH AREAS OF DENSE FOG AND IFR TO VLIFR CONDITIONS
BLANKETING KCID... KDBQ AND KMLI TERMINALS AND APPROACHING KBRL.
REGIONAL SOUNDINGS WITHIN STRATUS AND FOG SHOW MOISTURE 500-1000 FT
THICK AND EXTENDS INTO STRONG INVERSION... THUS PRESENTING CHALLENGE
AND LOW CONFIDENCE ON CLEARING THIS AFTN INTO TNGT. LATEST HRRR AND
RUC BACKUP MODELS HAVE DECENT HANDLE ON STRATUS AND FOG... AND SHOW
IMPROVEMENT THIS AFTN INTO MVFR TO VFR CONDITIONS THIS AFTN AND
EARLY EVE... AS WARMER AIR MOVES IN WESTERLY FLOW AT AROUND 925 MB.
CONCERN FOR TNGT WILL BE WITH REDEVELOPMENT OF FOG THAT COULD BE DENSE
IN AREAS. LATEST RUC BACKUP DEPICTS MORE WIDESPREAD DENSE FOG BY LATE
EVE INTO OVRNGT... BUT LOW CONFIDENCE DUE TO CLOUD TRENDS PRECLUDES
FROM DENSE FOG WITH VLIFR CONDITIONS. DID LOWER VSBYS AT TERMINALS TO
1-2SM BY MID EVE FOR NOW AND WAIT TO SEE HOW CLOUD TRENDS GO TDY.
WINDS NORTHWEST 3-8 KTS BECOMING LIGHT WEST TO SOUTHWEST BY TNGT.
.05..
&&
.PREV DISCUSSION... /ISSUED 320 AM CST WED FEB 1 2012/
SYNOPSIS...
EARLY AM SFC ANALYSIS PLACES LOW NORTH OF LAKE HURON JUST TO NORTH OF
SUDBURY ONTARIO. COLD FRONT TRAILS FROM THE LOW THROUGH CENTRAL IN
INTO NORTH TX. WEAK RIDGING EXTENDS FROM CENTRAL PLAINS INTO THE
UPPER MIDWEST. STRATUS WHICH FORMED OVER THE DAKOTAS INTO WESTERN MN
YSTDY CONTINUES TO EXPAND AND SURGE SOUTHEAST AIDED BY COLD
ADVECTION OVER EXISTING SNOWPACK NORTH AND MOIST BL FROM SNOW MELT.
LATEST 11-3.9 MICRON SATL IMAGERY SHOWS LEADING EDGE OF THE STRATUS
FROM KVTI TO KFEP MOVING SOUTHEAST AT AROUND 12 KTS. SOME FOG ALSO
OCCURRING WITH STRATUS... BUT VSBYS GENERALLY AT OR ABOVE 3SM ATTIM.
SHORT TERM...TODAY AND TONIGHT...
CLOUD TRENDS WITH IMPACT ON TEMPS... AND FOG POTENTIAL MAIN FCST
CONCERNS.
MOST MODELS STRUGGLING TO CAPTURE CURRENT STRATUS DECK... EXCEPT
FOR LATEST RUNS OF HRRR AND RUC BACKUP MODELS VIA ESRL. THESE
MODELS GENERALLY SUPPORT CONTINUED SOUTHEAST MOVEMENT THROUGH
DAYBREAK WITH MOST OF AREA NORTH OF HWY 34 BLANKETED BY THE STRATUS
BY MID AM. ONE CONCERN IS THAT RECENT SATL TRENDS SEEM TO SHOW THE
STRATUS CONTINUING TO SLOW... AND MAY BE DUE IN PART TO OUTRUNNING
THE SNOW FIELD AND MORE MOIST BL FROM SNOW MELT PAST 24 HRS NORTH OF
HWY 30. JUST WHERE LEADING EDGE OF STRATUS RESIDES BY MID AM
LIKELY TO BE IT FOR MOVEMENT AS STRENGTHENING SOLAR INSOLATION
LIKELY TO IMPEDE FURTHER PROGRESS. OF COURSE WHERE THIS ENDS UP WILL
BE HUGE FACTOR ON HIGH TEMPS. ANOTHER FACTOR IS EVOLUTION OF THE
EXISTING STRATUS THIS AFTN INTO TNGT AND WHETHER ANY CLEARING CAN
TAKE PLACE. LATEST HRRR AND RUC BACKUP MODELS DO SUPPORT DECREASE IN
STRATUS THIS AFTN... WITH HRRR SLIGHTLY SLOWER AND NOT UNTIL MID AFTN.
0412Z AMDAR ASCENT SOUNDING FROM KMSP SIMILAR TO 00Z MPX RAOB AND
SHOWS MOIST LAYER 500-1000 FT THICK... WITH MOISTURE LINGERING INTO
STRONG INVERSION AND NOT JUST BELOW IT. THIS IS A CONCERN AS IS FACT
THAT AREA WILL RESIDE IN WEAK SYNOPTIC SCALE FLOW... THUS MIXING WILL
BE LIMITED TO TAP DRY AIR ALOFT AND PROMOTE EROSION. THEREFORE
FAVOR SLOWER CLEARING TRENDS FROM HRRR... BUT ALSO MUST WONDER IF THE
STRATUS DOESNT DISSIPATE THIS AFTN WHAT WOULD PROMOTE EVACUATION TNGT.
SOME MODELS DO SHOW WARMING IN 925 MB LAYER TNGT AS FLOW IN THIS
LAYER BECOMES WESTERLY IN ASSOCIATION WITH CLIPPER TYPE SYSTEM PASSING
WELL NORTH INTO NORTHERN MN AND WI. THIS MAY BE ENOUGH TO CHEW AWAY AT
ANY RESIDUAL STRATUS... AND FOR NOW SKY COVER GRIDS EVOLVING TO MORE
OPTIMISTIC IN TIME. AS FOR TDY... WILL BE HEAVILY NOWCASTING CURRENT
STRATUS DECK AND USING HRRR AND RUC BACKUP MODELS FOR TRENDS. FOR NOW
WILL GO WITH IDEA OF STRATUS NEARING HWY 34 BY MID AM THEN LINGERING
INTO AFTN WITH SLOW EROSION THROUGH THIS EVE. ALL AREAS TDY WILL BE
COOLER... BUT TEMPS STILL ABOVE NORMAL. COOLEST READINGS BENEATH THE
STRATUS WHERE TEMPS COULD STRUGGLE TO 40 DEGS IF THEY HOLD ALL DAY.
OTRW... WARMEST READINGS SOUTH WHERE U40S TO L50S LOOK LIKELY WITH SOME
INCREASING HIGH CLOUDINESS. IN SHORT... AS CLOUDS GO... SO GO THE TEMPS.
WITH SOME UNCERTAINTY ON CLOUD TRENDS TNGT STAYED NEAR GUIDANCE BLEND
ON LOW TEMPS. FOG A POSSIBILITY TNGT WITH LIGHT BL FLOW AND LLVL MOISTURE
ESPECIALLY IN THOSE AREAS THAT SEE CLEARING LATE DAY INTO EARLY EVE.
IF STRATUS LINGERS WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG FORM ON
WESTERN EDGE. TOO UNCERTAIN THOUGH FOR ANY MENTION ATTIM BUT PASS ON THE
CONCERN TO DAY CREW. ..05..
LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
DRY AND QUIET CONDITIONS WILL BE SEEN THURS/THURS NIGHT AS HIGH
PRESSURE MOVES ACROSS THE AREA. TEMPERATURES WILL CONTINUE TO
AVERAGE ABOVE NORMAL.
STARTING FRIDAY...THINGS BECOME MORE INTERESTING. DPROG/DT CONTINUES
TO SHOW A SUBTLE SLOWING OF THE RESPECTIVE MODEL SOLUTIONS. HIGH
PRESSURE FROM THE NORTHERN PLAINS INTO THE GREAT LAKES CONTINUES TO
TREND STRONGER INDICATING A DEEPER FETCH OF DRY EASTERLY FLOW. THE
MAJOR UNKNOWN IS THE ENERGY CURRENTLY ENTERING THE GULF OF ALASKA
AND HOW IT WILL KICK OUT THE CUT OFF LOW IN THE PLAINS. ALL MODELS
CONTINUE TO SHOW VARIABILITY WHICH IS TRACEABLE TO HOW THE
RESPECTIVE ENERGIES INTERACT WITH EACH OTHER.
SO...FRIDAY MORNING WILL BE DRY WITH INCREASING CLOUDS. ALL MODELS
SHOW STRONG FORCING AND LOW CONDENSATION PRESSURE DEFICITS FROM
MISSOURI INTO CENTRAL IOWA ALONG WITH A GOOD MOISTURE FEED. OVER THE
CWFA...ALL MODELS SHOW EASTERLY FLOW FROM THE SFC UP THROUGH 850MB.
THUS PRECIP WILL NOT BE FAR AWAY FROM THE FAR SOUTHWEST PART OF THE
CWFA BY MID DAY FRIDAY.
FRIDAY AFTERNOON...THE DEEP AND DRY EASTERLY FLOW CONTINUES ACROSS
THE CWFA. BY MID TO LATE AFTERNOON 850-700MB CONDENSATION PRESSURE
DEFICITS COLLAPSE OVER ROUGHLY THE SOUTHWEST QUARTER OF THE CWFA
WITH GOOD FORCING. THE MOISTURE FEED BEGINS MOVING INTO THE CWFA AS
WELL. THE HEAVY RAIN AND LIFT TOOLS SHOW THE STRONG CONVERGENCE IS
THERE BUT WEAKENING WITH TIME. THUS RAIN SHOULD DEVELOP/MOVE INTO
THE CWFA IN AN ARCING LINE FROM NORTHERN KEOKUK COUNTY TO ROUGHLY
THE HANCOCK/MCDONOUGH BORDER BY EARLY EVENING. THE HIGHEST POPS WILL
BE IN THE FAR SOUTHWEST CORNER OF THE CWFA.
THE FACT THAT THE OVERALL CONVERGENCE IS WEAKENING WITH TIME PER THE
LIFT AND HEAVY RAIN TOOLS INDICATES THAT ANY CONVECTION THAT IS
OCCURRING ACROSS MISSOURI WILL BE STRATIFYING OUT AS IT MOVES INTO
THE CWFA. THUS ONLY RAIN IS EXPECTED THROUGH SUNSET.
FRIDAY NIGHT...THE WAA AND MOISTURE FINALLY WINS OUT OVER THE DRY
AIR BUT THE IMMEDIATE HWY 20 CORRIDOR WILL LIKELY REMAIN DRY THROUGH
MIDNIGHT. THE DRY EASTERLY FLOW WILL ALLOW EVAPORATIVE COOLING TO
OCCUR ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD. THIS
EVAPORATIVE COOLING WILL LIKELY RESULT IN A RAIN/SNOW MIX THAT
CHANGES OVER TO ALL SNOW IN THE HWY 20 CORRIDOR WITH ANY
ACCUMULATIONS BEING ONE HALF INCH OR LESS. THE HWY 30 CORRIDOR DOWN
TO ALMOST I-80 WILL LIKELY SEE A RAIN/SNOW MIX THAT DEVELOPS DURING
THE NIGHT.
SATURDAY ON...
MODEL CONSENSUS HAS LIKELY POPS FROM THE I-80 CORRIDOR ON SOUTH WITH
CHC POPS NORTH WHICH ARE LIKELY ON THE LOW SIDE. A RAIN/SNOW MIX
SHOULD BE ONGOING WITH SUNRISE OVER ROUGHLY THE NORTHERN 40 PERCENT
OF THE CWFA WITH RAIN ELSEWHERE. ANY MIX SHOULD CHANGE OVER TO A
VERY COLD RAIN AS THE DAY PROGRESSES. DYNAMIC COOLING COULD KEEP A
MIX GOING IN THE FAR NORTHWEST PART OF THE CWFA.
THE CONSENSUS GIVES CHC POPS SATURDAY NIGHT WITH SCHC POPS ON SUNDAY
AS ENERGY UPSTREAM KICKS THE STORM SYSTEM INTO THE EASTERN GREAT
LAKES. SUNDAY NIGHT THROUGH NEXT TUESDAY THE MODEL CONSENSUS HAS DRY
CONDITIONS ACROSS THE AREA AS NORTHWEST FLOW ALOFT DEVELOPS.
TEMPERATURES SATURDAY THROUGH TUESDAY SHOULD CONTINUE TO AVERAGE
ABOVE NORMAL BUT WILL BE MUCH CLOSER TO NORMAL SUNDAY THROUGH
TUESDAY. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-
JOHNSON-JONES-LINN-MUSCATINE-SCOTT.
IL...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR ROCK ISLAND.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
915 AM EST WED FEB 1 2012
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL MOVE EAST OF THE REGION THIS
MORNING. HIGH PRESSURE OVER THE WESTERN GREAT LAKES LATER TODAY
WILL MOVE OVER THE LOCAL AREA BY EARLY FRIDAY. THIS HIGH WILL
SHIFT TO THE EAST COAST BY THE START OF THE WEEKEND BUT MAINTAIN A
RIDGE ACROSS THE UPPER OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LITTLE CHANGE NEEDED TO FORECAST FOR 930 AM UPDATE AS THINGS
REMAIN ON TRACK. DRIER AIR SPREADING IN A MID AND LOW LEVELS WILL
DECREASE CLOUDS INTO EARLY AFTERNOON THEN CIRRUS MOVING IN WILL
PUT A HALF TO THE CLEARING. SOME ADJUSTMENT TO TEMPS AS CURRENT
CONDITIONS WARMER THAN EXPECTED IN THE EAST PART OF THE SNOWBELT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE REMAINDER OF THE
WEEK. AN UPPER WAVE WILL DIVE SE ACROSS THE CENTRAL LAKES ON
THURSDAY. THIS FEATURE WILL BRING SOME MID AND HIGH LEVEL
CLOUDINESS TO THE AREA BUT LOW LEVELS WILL REMAIN TOO DRY FOR ANY
PRECIP CONCERNS. THE HIGH WILL REESTABLISH ITSELF ON FRIDAY AND
FRIDAY NIGHT. THIS WILL RESULT IN MORE PARTLY CLOUDY TO MOSTLY
CLEAR SKIES. MODELS BEGIN TO DIVERGE ON SATURDAY WITH THE LOW
PRESSURE SYSTEM HEADING NE OUT OF THE SOUTHERN PLAINS. THE LATEST
GFS AND NAM BRING PRECIP INTO THE WESTERN END OF THE AREA AS EARLY
AS SATURDAY MORNING. THE LATEST ECMWF MAINTAINS A DRY EASTERLY
FLOW OVER THE REGION A WHILE LONGER AND THUS IS SLOWER WITH THE
PRECIP. WILL TREND TOWARD THIS DRIER AND SLOWER SOLUTION. HAVE
BACKED OFF ON PRECIP CHANCES FOR SATURDAY AND WILL KEEP IT ONLY IN
THE WEST SATURDAY NIGHT. THINK BETTER CHANCES WILL COME AFTER THE
SHORT TERM PERIOD ENDS. TEMPS WILL REMAIN MILD DURING THE PERIOD
AND HAVE USED A BLEND OF GUIDANCE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
STILL HAVE LOW CONFIDENCE IN THE LONG TERM FORECAST AND HAVE MADE
FEW CHANGES. ECMWF LINGERS THE CUTOFF LOW ACROSS THE MID SECTION OF
THE COUNTRY LONGER THAN THE GFS AND THIS SLOWER SOLUTION IS LIKELY
THE BETTER WAY TO GO. THE OTHER PROBLEM LIES WITH THE NORTHERN
STREAM AND THE TIMING OF A TROUGH TO COME DOWN ACROSS THE EASTERN
GREAT LAKES. HPC CONTINUES TO FAVOR THE ECENS FOR ITS SOMEWHAT
BETTER BIG PICTURE CONSISTENCY AND HAVE WEIGHTED THE FORECAST TO THE
OP ECMWF AND HPC/ECENS. THIS IS THE ROUTE WE HAVE BEEN TAKING AND
THEREFORE LITTLE HAS CHANGED TO THE FORECAST.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1130Z COLD FRONT WAS LOCATED FROM NEAR SANDUSKY TO FINDLAY.
SHOWERS WERE WELL AHEAD OF IT AND WERE ALREADY EXITING EASTERN
TAF SITES. CLEARING MOVING IN QUICKLY SO FIRST QUESTION WILL BE
HOW MUCH PROGRESS WILL IT MAKE. BOTH THE NAM AND THE HRRR GUIDANCE
CLEAR OUT THE LOW CLOUDS QUICKLY THIS MORNING AND HAVE FOLLOWED
THAT BECAUSE WHAT IS ALREADY OCCURRING UPSTREAM. ANOTHER AREA OF
MVFR CEILINGS WERE OVER THE CHICAGO AREA...BUT DO NOT THINK THESE
HAVE MUCH OF ANY CHANCE OF HOLDING TOGETHER TO REACH TOL. SOME
CIRRUS OVERHEAD LATER THIS AFTERNOON. WINDS AFTER THE FRONTAL
PASSAGE WILL BE FROM THE WEST AND WILL LOSE THE GUSTINESS.
DIFFERENCES EXIST ON AVIATION WEATHER FOR TONIGHT INTO THURSDAY.
THERE IS A SOUTHERN SYSTEM TO MOVE ACROSS KY AND THEN THERE WILL
BE A GENERAL TROUGH ALOFT PASSING. GFS LAMP DATA KEPT TODAY CLOUDY
WITH NON VFR CEILINGS AND KEPT THIS OVERNIGHT TOO...AND ACTUALLY
LOWERING TO IFR IN SOME PLACES. NAM GUID NOT SO PESSIMISTIC. WILL
TAKE MIDDLE ROAD FOR NOW AND JUST PUT IN SOME 3500 FT CEILINGS.
.OUTLOOK...NON-VFR CONDITIONS ARE POSSIBLE THURSDAY...LINGERING
ACROSS NE OH/NW PA INTO FRIDAY. NON VFR POSSIBLE AGAIN SUNDAY.
&&
.MARINE...
COLD FRONT TO CROSS THE LAKE THIS MORNING AND SHIFT WINDS TO THE
WEST. WINDS WILL DIMINISH BEHIND THE FRONT. SMALL CRAFT ADVISORY
WILL CONTINUE FOR TODAY FOR THE EAST HALF. HIGH PRESSURE CENTERED TO
THE NORTH OF THE LAKE WILL LARGELY DOMINATE FROM LATER TODAY THROUGH
FRIDAY. FOR THE WEEKEND AND EARLY NEXT WEEK...ONE SYSTEM WILL TRACK
EAST ACROSS THE OHIO VALLEY AND A TROUGH WILL AFFECT THE EASTERN
LAKES...ALTHOUGH FORECAST CONFIDENCE STILL REMAINS LOW FOR NEXT
WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...ADAMS/KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
647 AM EST WED FEB 1 2012
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL MOVE EAST OF THE REGION THIS
MORNING. HIGH PRESSURE OVER THE WESTERN GREAT LAKES LATER TODAY
WILL MOVE OVER THE LOCAL AREA BY EARLY FRIDAY. THIS HIGH WILL
SHIFT TO THE EAST COAST BY THE START OF THE WEEKEND BUT MAINTAIN A
RIDGE ACROSS THE UPPER OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE UPDATED THE FORECAST FOR CURRENT RADAR AND SATELLITE TRENDS.
THE NW TIP OF THE AREA HAS ALREADY CLEARED. RAPID CLEARING SHOULD
CONTINUE FROM TO WEST TO EAST THIS MORNING. LATEST GUIDANCE
CONTINUES TO SUGGEST THAT THE CLOUDS NEAR CHICAGO AND OVER
NORTHERN LOWER MI SHOULD STAY AWAY TODAY LEAVING ABUNDANT
SUNSHINE. THE REMAINING SHOWERS SHOULD BE GONE BY 13Z.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE REMAINDER OF THE
WEEK. AN UPPER WAVE WILL DIVE SE ACROSS THE CENTRAL LAKES ON
THURSDAY. THIS FEATURE WILL BRING SOME MID AND HIGH LEVEL
CLOUDINESS TO THE AREA BUT LOW LEVELS WILL REMAIN TOO DRY FOR ANY
PRECIP CONCERNS. THE HIGH WILL REESTABLISH ITSELF ON FRIDAY AND
FRIDAY NIGHT. THIS WILL RESULT IN MORE PARTLY CLOUDY TO MOSTLY
CLEAR SKIES. MODELS BEGIN TO DIVERGE ON SATURDAY WITH THE LOW
PRESSURE SYSTEM HEADING NE OUT OF THE SOUTHERN PLAINS. THE LATEST
GFS AND NAM BRING PRECIP INTO THE WESTERN END OF THE AREA AS EARLY
AS SATURDAY MORNING. THE LATEST ECMWF MAINTAINS A DRY EASTERLY
FLOW OVER THE REGION A WHILE LONGER AND THUS IS SLOWER WITH THE
PRECIP. WILL TREND TOWARD THIS DRIER AND SLOWER SOLUTION. HAVE
BACKED OFF ON PRECIP CHANCES FOR SATURDAY AND WILL KEEP IT ONLY IN
THE WEST SATURDAY NIGHT. THINK BETTER CHANCES WILL COME AFTER THE
SHORT TERM PERIOD ENDS. TEMPS WILL REMAIN MILD DURING THE PERIOD
AND HAVE USED A BLEND OF GUIDANCE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
STILL HAVE LOW CONFIDENCE IN THE LONG TERM FORECAST AND HAVE MADE
FEW CHANGES. ECMWF LINGERS THE CUTOFF LOW ACROSS THE MID SECTION OF
THE COUNTRY LONGER THAN THE GFS AND THIS SLOWER SOLUTION IS LIKELY
THE BETTER WAY TO GO. THE OTHER PROBLEM LIES WITH THE NORTHERN
STREAM AND THE TIMING OF A TROUGH TO COME DOWN ACROSS THE EASTERN
GREAT LAKES. HPC CONTINUES TO FAVOR THE ECENS FOR ITS SOMEWHAT
BETTER BIG PICTURE CONSISTENCY AND HAVE WEIGHTED THE FORECAST TO THE
OP ECMWF AND HPC/ECENS. THIS IS THE ROUTE WE HAVE BEEN TAKING AND
THEREFORE LITTLE HAS CHANGED TO THE FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1130Z COLD FRONT WAS LOCATED FROM NEAR SANDUSKY TO FINDLAY.
SHOWERS WERE WELL AHEAD OF IT AND WERE ALREADY EXITING EASTERN
TAF SITES. CLEARING MOVING IN QUICKLY SO FIRST QUESTION WILL BE
HOW MUCH PROGRESS WILL IT MAKE. BOTH THE NAM AND THE HRRR GUIDANCE
CLEAR OUT THE LOW CLOUDS QUICKLY THIS MORNING AND HAVE FOLLOWED
THAT BECAUSE WHAT IS ALREADY OCCURRING UPSTREAM. ANOTHER AREA OF
MVFR CEILINGS WERE OVER THE CHICAGO AREA...BUT DO NOT THINK THESE
HAVE MUCH OF ANY CHANCE OF HOLDING TOGETHER TO REACH TOL. SOME
CIRRUS OVERHEAD LATER THIS AFTERNOON. WINDS AFTER THE FRONTAL
PASSAGE WILL BE FROM THE WEST AND WILL LOSE THE GUSTINESS.
DIFFERENCES EXIST ON AVIATION WEATHER FOR TONIGHT INTO THURSDAY.
THERE IS A SOUTHERN SYSTEM TO MOVE ACROSS KY AND THEN THERE WILL
BE A GENERAL TROUGH ALOFT PASSING. GFS LAMP DATA KEPT TODAY CLOUDY
WITH NON VFR CEILINGS AND KEPT THIS OVERNIGHT TOO...AND ACTUALLY
LOWERING TO IFR IN SOME PLACES. NAM GUID NOT SO PESSIMISTIC. WILL
TAKE MIDDLE ROAD FOR NOW AND JUST PUT IN SOME 3500 FT CEILINGS.
.OUTLOOK...NON-VFR CONDITIONS ARE POSSIBLE THURSDAY...LINGERING
ACROSS NE OH/NW PA INTO FRIDAY. NON VFR POSSIBLE AGAIN SUNDAY.
&&
.MARINE...
COLD FRONT TO CROSS THE LAKE THIS MORNING AND SHIFT WINDS TO THE
WEST. WINDS WILL DIMINISH BEHIND THE FRONT. SMALL CRAFT ADVISORY
WILL CONTINUE FOR TODAY FOR THE EAST HALF. HIGH PRESSURE CENTERED TO
THE NORTH OF THE LAKE WILL LARGELY DOMINATE FROM LATER TODAY THROUGH
FRIDAY. FOR THE WEEKEND AND EARLY NEXT WEEK...ONE SYSTEM WILL TRACK
EAST ACROSS THE OHIO VALLEY AND A TROUGH WILL AFFECT THE EASTERN
LAKES...ALTHOUGH FORECAST CONFIDENCE STILL REMAINS LOW FOR NEXT
WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
517 AM EST WED FEB 1 2012
.SYNOPSIS...
UNSEASONABLY MILD TEMPERATURES WILL CONTINUE THROUGH THE
WEEK...BEFORE TRENDING BACK TOWARD NORMAL THIS WEEKEND. A WEAK
COLD FRONT WILL PUSH ACROSS TODAY...BRINGING LIGHT RAIN SHOWERS
FOR THE MORNING. A WEAK LOW PRESSURE AREA WILL SLIDE THROUGH THE
MID ATLANTIC STATES TONIGHT...BUT LITTLE OR NO RAIN WILL MAKE IT
NORTH OF THE MASON-DIXON LINE. HIGH PRESSURE WILL RIDGE IN FROM
THE UPPER GREAT LAKES LATE IN THE WEEK. ANOTHER WARM STORM IS
POSSIBLE LATE IN THE WEEKEND OR EARLY NEXT WEEK...BUT UNCERTAINTY
IS HIGH AS A REX BLOCK WILL DEVELOP OVER THE ROCKIES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT OVER LOWER MICHIGAN AND INDIANA WILL MOVE QUICKLY
THROUGH OHIO THIS MORNING AND THROUGH PENNSYLVANIA THIS AFTERNOON.
TWO STRIPES OF LIGHT RAIN SHOWERS EVIDENT ON THE RADAR THIS
MORNING WILL CONTINUE TO SLIDE EASTWARD...WITH THE EASTERN LIFT
WEAKENING VERY QUICKLY. HRRR HAS A GOOD PORTRAYAL OF THE
EVOLUTION OF THE PRECIP THESE LAST FEW HOURS...BUT NOW APPEARS TOO
SLOW IN MOVING THE PRECIP TO THE EAST. WILL HOLD SCT POPS FOR THE
MORNING IN THE EAST...BUT DOWNSLOPING WILL THEN KILL THE PRECIP
BACK CLOSER TO THE FRONT. THE FRONT WILL PASS WITH LITTLE FANFARE
DUE TO THE LOSS OF MOISTURE...MAINLY JUST A GUSTY WIND SHIFT. THE
FRONT WILL SETTLE ALONG A LATITUDE JUST SOUTH OF THE PA BORDER.
TEMPS ARE AGAIN A TOUGH CALL. ABOUT HALF OF THE AREA IN THE 60S
YESTERDAY...AND EARLY MORNING TEMPS ALREADY IN THE 40S...EXCEPT
FOR THE DEEP DARK VALLEY IN WILLIAMSPORT. CALM/LIGHT EASTERLY WIND
THERE INDICATIVE OF COLD AIR DAMMING. BUT AS YESTERDAY PLAYED
OUT...THE MIXING SHOULD EVENTUALLY GET DOWN THAT DEEP AS WELL.
WILL KEEP THE COOLEST MAXES IN THE NW WITH SCT SHRA THERE FOR MOST
OF THE MORNING AND PERHAPS INTO EARLY AFTN UNTIL FROPA...THEN CAA
KEEP THINGS STEADY OR BEGINNING TO FALL A LITTLE. THE REST OF THE
AREA COULD AGAIN TAKE A RUN AT THE M50S-60F. HAVE ONLY DRAWN IN
>60F TEMPS IN THE SERN THIRD OF THE AREA WHERE SKIES SHOULD BECOME
MOSTLY SUNNY THIS AFTERNOON AND DOWNSLOPE WILL HELP THE TEMPS IN
THEIR UNUSUAL CLIMB.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
SFC LOW WAY TO THE NORTH THIS MORNING WILL BE INTO NORTHERN NEW
ENGLAND BY LATE AFTN. THE FRONT WILL LAY OUT TO THE SOUTH OF THE
STATE TONIGHT...AND A SRN STREAM WAVE WILL ROLL UP FROM THE TN
VALLEY ALONG THE FRONT. THE PRECIP WILL HAVE A HARD TIME MAKING IT
NORTHWARD FROM THE GOMEX...AS THE LOW WILL BE CAUGHT IN A FAST
WRLY FLOW ALOFT. A GENERAL BUT ONLY SHORT FALL IN HEIGHTS WILL
HAPPEN AFTER THE LOW PASSES TO THE EAST. LOWS TONIGHT WILL DIP TO
THE M-U20S N AND L-M30S S. WILL CARRY JUST A SLIGHT CHC --RA IN
THE FAR SRN COS TONIGHT.
ALL EYES WILL BE JUST TO THE WEST OF THE CWA ON THURSDAY MORNING.
THE MORNING MAY BE RATHER CLOUDY OVER OUR WESTERN COUNTIES WITH
AN UPSLOPE FLOW INTO THE ALLEGHENIES. DAFFODILS ARE ALREADY
POPPING UP IN MY NEIGHBORS GARDEN DUE TO THE WARM AND WET SEASON
SO FAR. THUS...THE RODENT RUN WITH PERSISTENCE AND TURN A BLIND
EYE TO HIS SHADOW...OR HE MAY AND ARGUE THAT WINTER JUST HAS NOT
SHOWN UP YET AND GET A QUICK GLIMPSE.
IT IS A SAFE BET THAT IT WON/T STAY THIS WARM...BUT IT STILL LOOKS
WARM FOR THURSDAY. TEMPS WILL NOT BE AS LOFTY AS TUESDAY OR
TODAY...BUT WILL STILL BE 5 OR 6 DEGS ABOVE NORMALS AS THE MORNING
CLOUDS WILL DECREASE..ESPECIALLY IN THE EAST. THE CLEARING WILL
OCCUR AS THE LARGE DOME OF HIGH PRESSURE OVER CENTRAL CANADA NOSES
THROUGH THE UPPER GREAT LAKES AND INTO THE STATE. THURSDAY NIGHT
LOWS IN THE TEENS IN THE NORTH AND 20S IN THE S WILL STILL BE 4-6F
ABOVE NORMAL.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE STARTS OUT THE PERIOD IN
REASONABLY GOOD AGREEMENT...SHOWING AN EVOLVING REX BLOCK OVER THE
WEST-CENTRAL CONUS WITH CONFLUENT FLOW DOWNSTREAM IN THE
NORTHEAST. THE ECENS MEAN...AND THE GEFS MEAN TO A SLIGHTLY
LESSER EXTENT...HAVE SHOWN THE STRONGEST CONTINUITY OF THE
GUIDANCE OVER THE PAST SEVERAL MODEL CYCLES. THE MEANS CONTINUE TO
INDICATE THAT THE PRIMARY SYNOPTIC WAVE AFFECTING THE CONTIGUOUS
UNITED STATES WILL MARCH STEADILY ACROSS THE SOUTHERN
PLAINS...LOWER MISSISSIPPI AND TENNESSEE VALLEYS...AND SOUTHEAST
THROUGH THE WEEKEND..WITH HIGH PRESSURE LARGELY DOMINATING THE
WEATHER PATTERN IN THE NORTHEAST STATES. ALTHOUGH FORECASTER
CONFIDENCE HAS SLIGHTLY INCREASED GIVEN THE RELATIVE STABILITY IN
THE PATTERN NOTED IN THE ENSEMBLE DATA...WILL STILL LEAN HEAVILY
TOWARD A 50-50 GUIDANCE COMPROMISE/BLEND FOR SIGNIFICANT WEATHER
ELEMENTS THROUGHOUT THE EXTENDED PERIOD. MORNING PRELIMS WERE
NUDGED TOWARD THE LATER ARRIVING GMOS/HPC DATA.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
TAFS HOLDING UP WELL. A FEW MINOR CHANGES MADE AT 09Z.
EARLIER DISCUSSION BELOW.
CLEARING SKIES WILL ALLOW FOR TEMPERATURES TO PLUMMET AND THE
INVERSION TO TAKE HOLD...CUTTING OFF THE GUSTY WINDS DUE TO STRONG
FLOW ALOFT.
THE LLWS WILL PERSIST AS THE JET WILL BE AROUND 2000-4000 FT
AROUND 40-50 KTS THROUGH 15Z. MID LEVEL CLOUDS WILL BEGIN TO CREEP
IN FROM THE WEST BEFORE LOW PRESSURE SYSTEM AND THE ASSOCIATED
WEAK COLD FRONT SHOULD SLIDE BY TO OUR NORTH. LIGHT SHOWERS WILL
MOVE IN AFTER 06Z...WITH HIGHEST POPS IN THE NW MTNS TAPERING BACK
TO SCATTERED IN THE CENTRAL AND EAST. MVFR DEVELOPS AT KBFD LATE
TONIGHT...AND COULD SPREAD INTO CENTRAL MTNS BRIEFLY AROUND 12Z.
SHOWERS SHOULD CEASE 15 TO 18Z AS THE FRONT ELONGATES AND EXITS
EARLY TOMORROW AFTERNOON...WHICH SHOULD ALLOW CIGS/VSBY TO IMPROVE
TO VFR AREA-WIDE.
OUTLOOK...
THU...AM FOG POSSIBLE...ESP W MTNS.
FRI-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...CERU/MARTIN/RXR
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
923 AM CST WED FEB 1 2012
.UPDATE...
DENSE FOG IS LIFTING AND VISIBILITIES ARE IMPROVING ACROSS NORTH
TEXAS THIS MORNING SO HAVE LET THE DENSE FOG ADVISORY EXPIRE.
WATER VAPOR SHOWS UPPER LEVEL DISTURBANCE MOVING THROUGH THE
SOUTHERN PLAINS THIS MORNING. UPWARD FORCING FROM THIS FEATURE IS
HELPING TO RESULT IN A FEW ELEVATED SHOWERS AND THUNDERSTORMS
ACROSS PARTS OF OKLAHOMA AND NORTH TEXAS. THE 12Z FWD SOUNDING
INDICATED STEEP MID LEVEL LAPSE RATES WHICH WILL CONTINUE TO
SUPPORT THUNDERSTORMS THROUGH EARLY AFTERNOON. WITH CONTINUED
HEATING SOME SURFACE BASED STORMS MAY BE POSSIBLE BY EARLY
AFTERNOON MAINLY ACROSS THE NORTHEASTERN COUNTIES BEFORE THE
SYSTEM MOVES TO THE EAST OF THE AREA AND LARGE SCALE SUBSIDENCE
MOVES IN. WILL LEAVE 20 POPS IN ACROSS THE CENTRAL AND EASTERN
PART OF THE CWA THROUGH THIS AFTERNOON.
DUNN
&&
.AVIATION...
FOR THE 12Z TAFS...FOG AND LOW STRATUS IN THE FIRST FEW HOURS OF
THE VALID FORECAST PERIOD ARE THE PRIMARY CONCERNS. VFR CONDITIONS
ARE EXPECTED FROM LATE THIS MORNING THRU THE END OF THE FORECAST
PERIOD.
AREAS OF DENSE FOG HAD DEVELOPED ACROSS THE EASTERN HALF OF NORTH
TEXAS EARLY THIS MORNING. THE WORST OF THE FOG WAS RELEGATED TO
KGKY FOR METROPLEX TAF SITES AND KACT REMAINS SOCKED IN WITH 1/4
MILE FOG AT THE TIME OF THIS DISCUSSION. EXPECT IFR CONDITIONS TO
PERSIST AT KGKY THRU 14Z WHEN VEERING WINDS AND THE APPROACH OF A
WEAK COLD FRONT SHOULD BE SUFFICIENT TO DISSIPATE LOWER VSBYS IN
SOUTHERN TARRANT COUNTY. IFR CONDITIONS ARE LIKELY TO PERSIST AT
KACT THRU AT LEAST 15Z. DID NOT EXTEND FLIGHT RESTRICTIONS BEYOND
15Z AT THIS TIME AS KACT REMAINS ON THE WESTERN PERIPHERY OF THE
BANK OF DENSE FOG AND THEREFORE CAN BE EXPECTED TO RESPOND QUICKLY
TO HEATING AFTER SUNRISE. A WEAK FRONTAL BOUNDARY IS EXPECTED TO
PUSH THROUGH NORTH TX A BIT FASTER THAN PREVIOUS FORECAST
INDICATED. LATEST RUC GUIDANCE BRINGS THE FRONT THRU THE METROPLEX
DURING THE EARLY AFTERNOON HRS AND THEN THRU WACO AROUND 21Z.
DRIER AIR BEHIND THE FRONT SHOULD ENSURE VFR CONDITIONS FOR THE
NEXT 24 HRS AT AREA TAF SITES.
CANNOT RULE OUT SOME RAIN SHOWER OR ISOLATED TSTM ACTIVITY ALONG
THE COLD FRONT THIS AFTERNOON. DO NOT HAVE ANY MENTION OF
PRECIPITATION IN THE TAFS AT THIS TIME AS COVERAGE IS EXPECTED TO
BE LIMITED DUE TO MEAGER FORCING FOR ASCENT ALONG THE COLD FRONT.
WILL MONITOR FOR SIGNS OF DEVELOPMENT AND AMEND TAFS IF NECESSARY
THIS MORNING.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 514 AM CST WED FEB 1 2012/
SHALLOW DENSE FOG DEVELOPED IN THE NEAR-CALM SURFACE LAYER.
ADVISORY COVERS MUCH OF THE AREA WHERE PATCHY DENSE FOG
PERSISTS...BUT SOME SHALLOW FOG WILL CONTINUE ELSEWHERE.
TODAY...
DIFFUSE FRONTAL BOUNDARY REMAINS NEAR NORTHWESTERN EDGE OF CWA.
DESPITE ORIENTATION OF EARLY MORNING CONVECTION...FLOW WITHIN THE
LAYER OF LIFT IS PARALLEL TO THE BOUNDARY. THIS AREA OF RATHER
BENIGN CONVECTION WILL SLOWLY TRANSLATE NORTHEAST INTO NE ZONES
OVER THE COURSE OF THE DAY. FRONT WILL PENETRATE CWA TODAY...AND
THE BOUNDARY WILL INTERACT WITH UNSEASONABLY WARM BOUNDARY LAYER.
AS WINDS PICK UP...THE 60F ISODROSOTHERM WILL MOVE FARTHER
INLAND...RESULTING IN MUCAPE VALUES IN EXCESS OF 1000 J/KG. BUT
WITH MINIMAL LOW-LEVEL CONVERGENCE AND RATHER SHALLOW MOISTURE...
HAVE LOW CONFIDENCE IN WIDESPREAD CONVECTION THIS AFTERNOON. WITH
MESOSCALE MODELS RATHER GUN-SHY...WILL MAINTAIN 20 POPS IN
EAST/SOUTHEAST ZONES.
FRIDAY EVENT...
TROUGH CURRENTLY OVER THE ALEUTIANS WILL QUICKLY DEEPEN AS IT
ENTRAINS BITTER COLD FROM THE POLAR VORTEX NEAR THE ARCTIC COAST
OF ALASKA. THE RESULTING DOWNSTREAM RIDGE WILL PUSH THE TROUGH
CURRENTLY NEAR THE WEST COAST OF THE CONUS EASTWARD. THE
AMPLIFICATION OF THE RIDGE AS IT REACHES THE WEST COAST WILL ALLOW
THIS TROUGH TO PULL POLAR AIR INTO THE INTERMOUNTAIN WEST...
DEEPENING THE FEATURE INTO A CLOSED LOW AS EARLY AS THURSDAY.
WARM ADVECTION AHEAD OF THE SYSTEM MAY ALLOW SOME SHOWERS
(ISOLATED THUNDER) TO DEVELOP LATE THURSDAY. THE UPGLIDE WILL
INCREASE DRAMATICALLY THURSDAY NIGHT...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS LIKELY BY DAYBREAK FRIDAY. SIGNIFICANT FORCING WILL
MEAN STRONG CONVECTION COULD ACCOMPANY FROPA LATE FRIDAY...BUT
STILL HAVE CONCERNS THAT PRECIP EARLY IN THE DAY WILL LIMIT
INSTABILITY FOR THE MAIN EVENT. WHILE THERE IS GOOD INTER-MODEL
AGREEMENT INTO FRIDAY ON THE SYNOPTIC SCALE AS GUIDANCE IS ABLE TO
RESOLVE A WELL BEHAVED SYSTEM WITHIN THE POLAR STREAM...IT IS TOO
EARLY TO PERFECT PROG THE MESOSCALE EVOLUTION OF THE EVENT.
WEEKEND...
BY FRIDAY NIGHT...THE POLAR JET CUTS THE LOW OFF...AND SOLUTIONS
DIVERGE AS A RESULT. DESPITE SOME UNCERTAINTY IN FRONTAL TIMING...
WILL CONTINUE TO TAPER OFF POPS FRIDAY NIGHT. TEMPS CLOSER TO
NORMAL WILL PREVAIL THIS WEEKEND. ONCE LOW FINALLY EJECTS...A
REINFORCING SHOT OF COLD AIR WILL INVADE SATURDAY NIGHT AND
SUNDAY. SOME MOIST UPGLIDE WILL BY POSSIBLE EARLY SUNDAY IN
SOUTHERN ZONES...BUT EXPECT THE THIN MOISTURE TO ONLY YIELD A
CLOUD LAYER. MEX GUIDANCE APPEARS TOO BULLISH...WILL MAINTAIN POP-
FREE FORECAST BEYOND FRIDAY NIGHT.
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 75 52 72 61 74 / 20 10 10 50 80
WACO, TX 74 50 72 59 75 / 20 10 10 50 80
PARIS, TX 70 52 68 58 72 / 20 10 10 50 80
DENTON, TX 72 45 70 58 73 / 20 10 10 50 80
MCKINNEY, TX 72 45 69 56 74 / 20 10 10 50 80
DALLAS, TX 73 53 72 61 75 / 20 10 10 50 80
TERRELL, TX 73 52 72 60 73 / 20 10 10 50 80
CORSICANA, TX 75 55 76 61 74 / 20 10 20 50 80
TEMPLE, TX 77 52 75 59 73 / 10 10 10 50 70
MINERAL WELLS, TX 72 44 69 56 71 / 20 10 10 50 80
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
601 AM CST WED FEB 1 2012
.AVIATION...
FOR THE 12Z TAFS...FOG AND LOW STRATUS IN THE FIRST FEW HOURS OF
THE VALID FORECAST PERIOD ARE THE PRIMARY CONCERNS. VFR CONDITIONS
ARE EXPECTED FROM LATE THIS MORNING THRU THE END OF THE FORECAST
PERIOD.
AREAS OF DENSE FOG HAD DEVELOPED ACROSS THE EASTERN HALF OF NORTH
TEXAS EARLY THIS MORNING. THE WORST OF THE FOG WAS RELEGATED TO
KGKY FOR METROPLEX TAF SITES AND KACT REMAINS SOCKED IN WITH 1/4
MILE FOG AT THE TIME OF THIS DISCUSSION. EXPECT IFR CONDITIONS TO
PERSIST AT KGKY THRU 14Z WHEN VEERING WINDS AND THE APPROACH OF A
WEAK COLD FRONT SHOULD BE SUFFICIENT TO DISSIPATE LOWER VSBYS IN
SOUTHERN TARRANT COUNTY. IFR CONDITIONS ARE LIKELY TO PERSIST AT
KACT THRU AT LEAST 15Z. DID NOT EXTEND FLIGHT RESTRICTIONS BEYOND
15Z AT THIS TIME AS KACT REMAINS ON THE WESTERN PERIPHERY OF THE
BANK OF DENSE FOG AND THEREFORE CAN BE EXPECTED TO RESPOND QUICKLY
TO HEATING AFTER SUNRISE. A WEAK FRONTAL BOUNDARY IS EXPECTED TO
PUSH THROUGH NORTH TX A BIT FASTER THAN PREVIOUS FORECAST
INDICATED. LATEST RUC GUIDANCE BRINGS THE FRONT THRU THE METROPLEX
DURING THE EARLY AFTERNOON HRS AND THEN THRU WACO AROUND 21Z.
DRIER AIR BEHIND THE FRONT SHOULD ENSURE VFR CONDITIONS FOR THE
NEXT 24 HRS AT AREA TAF SITES.
CANNOT RULE OUT SOME RAIN SHOWER OR ISOLATED TSTM ACTIVITY ALONG
THE COLD FRONT THIS AFTERNOON. DO NOT HAVE ANY MENTION OF
PRECIPITATION IN THE TAFS AT THIS TIME AS COVERAGE IS EXPECTED TO
BE LIMITED DUE TO MEAGER FORCING FOR ASCENT ALONG THE COLD FRONT.
WILL MONITOR FOR SIGNS OF DEVELOPMENT AND AMEND TAFS IF NECESSARY
THIS MORNING.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 514 AM CST WED FEB 1 2012/
SHALLOW DENSE FOG DEVELOPED IN THE NEAR-CALM SURFACE LAYER.
ADVISORY COVERS MUCH OF THE AREA WHERE PATCHY DENSE FOG
PERSISTS...BUT SOME SHALLOW FOG WILL CONTINUE ELSEWHERE.
TODAY...
DIFFUSE FRONTAL BOUNDARY REMAINS NEAR NORTHWESTERN EDGE OF CWA.
DESPITE ORIENTATION OF EARLY MORNING CONVECTION...FLOW WITHIN THE
LAYER OF LIFT IS PARALLEL TO THE BOUNDARY. THIS AREA OF RATHER
BENIGN CONVECTION WILL SLOWLY TRANSLATE NORTHEAST INTO NE ZONES
OVER THE COURSE OF THE DAY. FRONT WILL PENETRATE CWA TODAY...AND
THE BOUNDARY WILL INTERACT WITH UNSEASONABLY WARM BOUNDARY LAYER.
AS WINDS PICK UP...THE 60F ISODROSOTHERM WILL MOVE FARTHER
INLAND...RESULTING IN MUCAPE VALUES IN EXCESS OF 1000 J/KG. BUT
WITH MINIMAL LOW-LEVEL CONVERGENCE AND RATHER SHALLOW MOISTURE...
HAVE LOW CONFIDENCE IN WIDESPREAD CONVECTION THIS AFTERNOON. WITH
MESOSCALE MODELS RATHER GUN-SHY...WILL MAINTAIN 20 POPS IN
EAST/SOUTHEAST ZONES.
FRIDAY EVENT...
TROUGH CURRENTLY OVER THE ALEUTIANS WILL QUICKLY DEEPEN AS IT
ENTRAINS BITTER COLD FROM THE POLAR VORTEX NEAR THE ARCTIC COAST
OF ALASKA. THE RESULTING DOWNSTREAM RIDGE WILL PUSH THE TROUGH
CURRENTLY NEAR THE WEST COAST OF THE CONUS EASTWARD. THE
AMPLIFICATION OF THE RIDGE AS IT REACHES THE WEST COAST WILL ALLOW
THIS TROUGH TO PULL POLAR AIR INTO THE INTERMOUNTAIN WEST...
DEEPENING THE FEATURE INTO A CLOSED LOW AS EARLY AS THURSDAY.
WARM ADVECTION AHEAD OF THE SYSTEM MAY ALLOW SOME SHOWERS
(ISOLATED THUNDER) TO DEVELOP LATE THURSDAY. THE UPGLIDE WILL
INCREASE DRAMATICALLY THURSDAY NIGHT...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS LIKELY BY DAYBREAK FRIDAY. SIGNIFICANT FORCING WILL
MEAN STRONG CONVECTION COULD ACCOMPANY FROPA LATE FRIDAY...BUT
STILL HAVE CONCERNS THAT PRECIP EARLY IN THE DAY WILL LIMIT
INSTABILITY FOR THE MAIN EVENT. WHILE THERE IS GOOD INTER-MODEL
AGREEMENT INTO FRIDAY ON THE SYNOPTIC SCALE AS GUIDANCE IS ABLE TO
RESOLVE A WELL BEHAVED SYSTEM WITHIN THE POLAR STREAM...IT IS TOO
EARLY TO PERFECT PROG THE MESOSCALE EVOLUTION OF THE EVENT.
WEEKEND...
BY FRIDAY NIGHT...THE POLAR JET CUTS THE LOW OFF...AND SOLUTIONS
DIVERGE AS A RESULT. DESPITE SOME UNCERTAINTY IN FRONTAL TIMING...
WILL CONTINUE TO TAPER OFF POPS FRIDAY NIGHT. TEMPS CLOSER TO
NORMAL WILL PREVAIL THIS WEEKEND. ONCE LOW FINALLY EJECTS...A
REINFORCING SHOT OF COLD AIR WILL INVADE SATURDAY NIGHT AND
SUNDAY. SOME MOIST UPGLIDE WILL BY POSSIBLE EARLY SUNDAY IN
SOUTHERN ZONES...BUT EXPECT THE THIN MOISTURE TO ONLY YIELD A
CLOUD LAYER. MEX GUIDANCE APPEARS TOO BULLISH...WILL MAINTAIN POP-
FREE FORECAST BEYOND FRIDAY NIGHT.
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 75 52 72 61 74 / 10 10 10 50 80
WACO, TX 74 50 72 59 75 / 10 10 10 50 80
PARIS, TX 70 52 68 58 72 / 20 10 10 50 80
DENTON, TX 72 45 70 58 73 / 20 10 10 50 80
MCKINNEY, TX 72 45 69 56 74 / 20 10 10 50 80
DALLAS, TX 73 53 72 61 75 / 10 10 10 50 80
TERRELL, TX 73 52 72 60 73 / 20 10 10 50 80
CORSICANA, TX 75 55 76 61 74 / 20 10 20 50 80
TEMPLE, TX 77 52 75 59 73 / 10 10 10 50 70
MINERAL WELLS, TX 72 44 69 56 71 / 20 10 10 50 80
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR TXZ094-095-
104>107-120>123-133>135-145>148-158>162-174-175.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
549 AM CST WED FEB 1 2012
.SHORT TERM...
549 AM CST WED FEB 1 2012
AS THE SURFACE WINDS HAVE CONTINUED TO SLOWLY DIMINISH THROUGH THE
NIGHT...THE VISIBILITY HAS SLOWLY GONE DOWN AS WELL. VISIBILITIES
ACROSS MUCH OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA HAVE GONE
DOWN TO A HALF MILE OR LESS. WITH AIR TEMPERATURES BELOW
FREEZING...THE FOG MAY BE DEPOSITING A THIN LAYER OF ICE ON ANY
UNTREATED SURFACES. THE 01.09Z RUC REALLY DOES NOT SHOW ANY
SIGNIFICANT IMPROVEMENT POSSIBLE THROUGH MUCH OF THE MORNING. THE
STRATUS DECK ABOVE THE FOG IS EXPECTED TO REMAIN IN PLACE AND THE
WINDS WILL REMAIN LIGHT. TEMPERATURES MAY GET ABOVE FREEZING BY
LATE MORNING TO ELIMINATE THE ICING THREAT...BUT CONCERNED THE
VISIBILITY MAY NOT IMPROVE MUCH UNTIL AFTERNOON. HAVE COORDINATED
AN ENDING TIME OF A DENSE FOG ADVISORY WITH SURROUNDING
OFFICES...BUT WOULD NOT BE SURPRISED IF THIS HAS TO BE EXTENDED.
.LONG TERM...SATURDAY THROUGH TUESDAY
320 AM CST WED FEB 1 2012
01.00Z MEDIUM RANGE MODEL CONSENSUS SLOWLY IMPROVING IN THE DAY 4-7
TIME-FRAME...BUT STILL PLENTY OF DIFFERENCES AND POOR RUN-TO-RUN
CONSISTENCY BY SAT. MODEL DIFFERENCES RESULT IN SIGNIFICANT
SENSIBLE WEATHER DIFFERENCES FOR PARTS OR ALL OF THE FCST AREA
SAT/SUN. INTERESTING THAT GFS WITH THE MOST NORTHERLY SOLUTION OF
THE 31.00Z RUNS IS NOW THE MORE SOUTHERLY SOLUTION. THE ECMWF HAS
FLIPPED THESE ROLES TOO AND IS NOW ONE OF THE MORE NORTHERLY
SOLUTIONS. NEEDLESS TO SAY...FCST CONFIDENCE BY SAT/SUN ON THE LOW
SIDE. GIVEN THE FLIP-FLOPPING OF THE MODELS AND BELOW AVERAGE RUN-
TO-RUN CONSISTENCY...NOT WILLING TO POINT TO ANY ONE DETERMINISTIC
MODEL AS A PREFERRED CHOICE FOR THE UPCOMING WEEKEND. USED THE
MODEL/ENSEMBLE CONSENSUS FOR SAT/SUN...WITH 20 TO 40 PERCENT SNOW OR
-RA/-SN CHANCES...HIGHEST ACROSS THE SOUTH END OF THE FCST AREA.
MON/TUE TREND DRY WITH A DRIER WEST/NORTHWEST FLOW SPREADING ACROSS
THE UPPER MIDWEST. HOWEVER CONFIDENCE NOT HIGH HERE EITHER WITH
OUTCOME OF SAT/SUN TO WEIGH INTO FLOW EVOLUTION FOR EARLY NEXT
WEEK...AND MODELS SHOWING POTENTIAL FOR A NORTHWEST FLOW SHORTWAVE
OR TWO TO DROP INTO/ACROSS THE REGION. BETTER CONFIDENCE FOR TEMPS
TO REMAIN ABOVE NORMAL FOR SAT-TUE WITH ARCTIC AIR REMAINING WELL
NORTH IN CANADA.
&&
.AVIATION...TODAY AND TONIGHT
549 AM CST WED FEB 1 2012
WHEN AND IF THE STRATUS DECK WILL LEAVE THE AREA IS THE BIG
QUESTION. THE WESTERN EDGE OF THE STRATUS AT THIS POINT IS JUST
AHEAD OF A WEAK 925 MB TROUGH AXIS OVER THE EASTERN DAKOTAS. THE
01.06Z NAM AND 01.09Z RUC SUGGEST THIS TROUGH AXIS AND THUS THE
MOISTURE FIELD WILL NOT PASS EAST OF THE TAF SITES UNTIL THIS
EVENING. HAVE PUSHED BACK THE CLEARING TRENDS FOR BOTH TAF SITES
UNTIL THE MID EVENING AND THEN CONCERNED THAT THIS MAY BE TOO
SOON. THE VISIBILITY AT KRST IS ALSO NOT EXPECTED TO IMPROVE VERY
FAST TODAY. HAVE KEPT THE VISIBILITY BELOW A MILE THROUGH THE
MORNING AND THEN BROUGHT IT UP TO IFR WITH A SLIGHT WIND SHIFT TO
THE SOUTHWEST AS THE TROUGH AXIS STARTS TO APPROACH. IF THIS BATCH
OF STRATUS CAN CLEAR OUT THIS EVENING...CONCERNED THAT THE
VISIBILITY COULD GO BACK DOWN TO MVFR OR IFR AGAIN WITH DECENT
RADIATIONAL COOLING CONDITIONS. INCLUDED THIS POSSIBILITY AT BOTH
TAF SITES AND IF THE INVERSION DOES NOT GET MIXED OUT BEHIND THE
PASSAGE OF THE TROUGH AXIS...COULD SEE THE STRATUS REDEVELOPING
AGAIN AS THE AIR BEGINS TO COOL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
549 AM CST WED FEB 1 2012
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ079-
086>088-094>096.
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...04
LONG TERM....RRS
AVIATION...04
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
150 PM PST WED FEB 1 2012
.SYNOPSIS...WEAK UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE
OVER THE FORECAST AREA THIS WEEK PRODUCING INTERMITTENT SCATTERED
MIDDLE AND HIGH CLOUDS BUT LITTLE IF ANY PRECIPITATION. VALLEY FOG
REMAINS A POSSIBILITY DURING THE NIGHTS AND MORNINGS.
&&
.DISCUSSION...COOL AND DRY UPPER NORTHERLY FLOW PREVAILING OVER
CENTRAL CA AT THIS TIME AS OUR AREA REMAINS SITUATED IN BETWEEN A
DEPARTED UPPER TROUGH OVER THE GREAT BASIN AND AN OFFSHORE RIDGE.
THE RIDGE IS PROGGED BY THE 12Z WRF AND GFS TO AMPLIFY OFF THE CA
COAST TONIGHT THEN BUILD INLAND ON THURSDAY. ONSHORE P-GRADS HAVE
STRENGTHENED WITH KSFO-KLAS AT 10.4 MB AND KBFL-KNID AT 6.7 MB AT
NOON TODAY. HI RESOLUTION RUC INDICATING P-GRADS WILL MAX OUT
LATER THIS AFTERNOON THEN WEAKEN RAPIDLY THIS EVENING. THE
INCREASED SURFACE GRADIENTS WILL RESULT IN A PERIOD OF BREEZY
CONDITIONS ACORSS THE KERN COUNTY MOUNTAINS AND DESERTS THROUGH
EARLY THIS EVENING...BUT DO NOT EXPECT WINDS TO REACH WIDESPREAD
ADVISORY CRITERIA. IN THE MEANTIME...SOME UPSLOPE STRATO-CUMULUS
HAS FORMED OVER THE SOUTHERN SIERRA FOOTHILLS WHILE SOME
INSTABILITY CUMULUS HAS PUSHED SOUTHWARD INTO MERCED COUNTY.
EXPECT THESE CLOUDS TO DISSIPATE TONIGHT AS CAA CONTINUES TONIGHT
AND MIXES OUT THE ATMOSPHERE. THE NORTHERLY FLOW PATTERN WILL ALSO
INHIBIT THE DEVELOPMENT OF WIDESPREAD FOG IN THE SAN JOAQUIN
VALLEY TONIGHT...BUT THERE IS ENOUGH RESIDUAL LOW LEVEL MOISTURE
NEAR THE VALLEY FLOOR SO SOME PATCHY FOG IS NOT OUT OF THE
QUESTION FOR TONIGHT.
MODEL CONSENSUS INDICATES THE RIDGE WILL KEEP DRY CONDITIONS OVER
OUR AREA THURSDAY THROUGH THE UPCOMING WEEKEND. TEMPERATURES WILL
RISE TO ABOVE SEASONAL NORMALS AS THE RIDGE STRENGTHENS OVER THE
AREA FRIDAY THROUGH THE WEEKEND. THE ONLY FORECAST PROBLEM FOR
THIS PERIOD WILL BE THE THE EXTENT OF ANY NIGHT AND MORNING FOG
IN THE SAN JOAQUIN VALLEY AND SUBSEQUENT IMPACT IT MAY HAVE ON
TEMPERATURES. THE INCREASING SUN ANGLE WILL LIKELY ALLOW FOR ANY
FOG THAT DOES FOR TO COMPLETELY BURN OFF BY LATE MORNING EACH
DAY...THAT IS UNLESS THE RIDGE COMPLETELY SQUISHES OUT ANY LOW
LEVEL MOISTURE.
THE 12Z GFS AND ECMWF BOTH INDICATE THE RIDGE WILL BREAK DOWN ON
MONDAY AND A SPLIT TROUGH WILL REACH THE CA COAST BY TUESDAY.
THE ECMWF IS SOMEWHAT MORE ROBUST WITH THE SPLITTING AND JUST
BRINGING A DEFORMATION BAND OF MID/UPPER LEVEL MOISTURE THROUGH
OUR AREA WHILE THE GFS HOLDS MORE OF IT TOGETHER AND BRING SOME
DEEPER MOISTURE INTO OUR AREA WHILE IT MOVES THROUGH CA ON TUESDAY
AND TUESDAY NIGHT. HAVE DECIDED TO COMPROMISE BETWEEN THE TWO
SOLUTIONS AND KEEP MENTION OF A SLIGHT CHANCE TO LOW CHANCE OF
RAIN AND MOUNTAIN SNOW FOR FRESNO COUNTY NORTHWARD TUESDAY AND
TUESDAY NIGHT TAPERING TO MOUNTAIN SHOWERS ON WEDNESDAY. ENSEMBLE
MEMBER AGREEMENT IS POOR SO DO NOT HAVE A LOT OF CONFIDENCE IN
DAYS 6 AND 7 AT THIS TIME.
&&
.AVIATION...IN THE SAN JOAQUIN VALLEY...LOCAL IFR/LIFR
VISIBILITIES CAN BE EXPECTED BETWEEN 09Z AND 18Z THURSDAY.
OTHERWISE...AREAS OF MVFR IN HAZE CAN BE EXPECTED THROUGH 00Z
FRIDAY. LOCAL MVFR CONDITIONS IN THE LOWER SLOPES OF THE SOUTHERN
SIERRA NEVADA THROUGH 04Z THURSDAY. OTHERWISE VFR CONDITIONS WILL
PREVAIL ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 00Z FRIDAY.
&&
.AIR QUALITY ISSUES...ON WEDNESDAY FEBRUARY 1 2012... UNHEALTHY
FOR SENSITIVE GROUPS IN KERN AND TULARE COUNTIES. FIREPLACE/WOOD
STOVE BURNING IS PROHIBITED IN FRESNO... KERN... KINGS AND TULARE
COUNTIES. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG
&&
.HNX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...DS
AVN/FW...BEAN
SYNOPSIS...WP
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
233 PM EST WED FEB 1 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A NORTH SOUTH AREA OF HIGH PRESSURE WILL DOMINATE INDIANA WEATHER
INTO FRIDAY. OVER THE WEEKEND LOW PRESSURE WILL MOVE TOWARD AND THEN
CROSS OUR STATE. HIGH PRESSURE IS EXPECTED TO RETURN MONDAY AND A
WEAK COLD FRONT IS FORECAST TO PASS TUESDAY. BY MIDWEEK HIGH
PRESSURE WILL BE BACK.
&&
.NEAR TERM /TONIGHT/...
BOTH SATELLITE OBSERVATIONS AND MODEL MOISTURE FIELDS SUPPORT PARTLY
CLOUDY TONIGHT. THIS LEAVES TEMPERATURES AS FORECAST PROBLEM.
MAV AND MET ARE CLOSE...BUT MET IS JUST SLIGHTLY COOLER. BASED ON
WHAT HAPPENED UPSTREAM LAST NIGHT I WILL USE THE MET.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MAIN PROBLEM IS WHEN PRECIPITATION WILL DEVELOP. ALL THE MODELS
AGREE WE ONLY HAVE TO WORRY ABOUT RAIN.
NAM...AND ASSOCIATED MET...BRING IN RAIN FASTER THAN GFS AND MAV. I
GOING TO UAW THE MAV. LATEST NAM IS NOT VERY CONSISTENT WITH ITS OWN
PREVIOUS RUN...OR THE SREF. THIS SUGGESTS IT IS AN OUTLIER.
FRIDAY NIGHT AND SATURDAY ALL MODELS PUT AT LEAST SOME QPF
EVERYWHERE IN THE CWA. IN MOST PLACES WILL USE LIKELY. EXCEPTION IS
THE EXTREME NORTHEAST FRIDAY NIGHT WHERE I WILL TAKE THE RELATIVELY
LOW POPS TO A HIGH CHANCE.
MAV HAS BEEN DOING WELL WITH TEMPERATURES LATELY. WILL USE THAT
THROUGH FRIDAY NIGHT WITH LITTLE CHANGE. SATURDAY MEX HIGHS ARE
ABOVE THE GFS HIGHS FROM THE MEN. SPLIT BETWEEN MEN HIGHS AND MEN
AVERAGES LOOKS BETTER TO ME GIVEN RAIN IS FORECAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
CLOUDY DAMP WEEKEND THEN IMPROVING...BUT TREND TOWARD COOLER
WEATHER.
FORECAST PROBLEM REMAINS WITH EVOLUTION AND MOVEMENT OF WEATHER
SYSTEM THIS WEEKEND AND APPEARS BEST BET IS A MELDING OF SOLUTIONS
WITH A LEAN TOWARD SLOWER MODELS WITH GEM PERHAPS A MID-WAY
SOLUTION AMONG ALL. IN THE END THE DIFFERENCE PRIMARILY TIES TO
HOW SOON COLD AIR IN SYSTEM COMMA HEAD WRAPS INTO INDIANA AND
WHETHER OR NOT ANY SNOW WOULD MIX IN.
AT THIS POINT...PRETTY HIGH CONFIDENCE NO SNOW WILL OCCUR UNTIL
LATE SUNDAY NIGHT AND EVEN THAT SHOULD BE LIGHT AND NOT ACCUMULATE
GIVEN THE INTENSITY EXPECTED AND THE WET WARM GROUND THAT WILL
PREVAIL INTO THAT TIME FRAME.
THERE IS SIMILARITY IN THE MODELS...EXCEPT FOR THE SLOWEST...EURO
SOLUTION...IN THAT A DRY SLOT WRAPS INTO CENTRAL INDIANA SATURDAY
NIGHT AND PART OF SUNDAY. THIS WOULD IMPLY ANY RAIN THAT DOES
OCCUR WOULD BE VERY LIGHT...PERHAPS BECOMING MORE OF A DRIZZLE.
CONTINUING INTO SUNDAY...WITH TEMPS AT OR ABOVE FREEZING...AGAIN
EXPECTING NO MORE THAN A LIGHT RAIN OR DRIZZLE...AND POTENTIAL
EXISTS FOR FAIR SHARE OF SAATURDAY NIGHT TO SUNDAY NIGHT HAVING
DRY PERIODS. AS WEATHER SYSTEM CONTINUES TO DEPART TO THE EAST
LINGERING CLOUDS COULD SPIT A FEW FLURRIES MONDAY BUT PROBABILITY
TOO LOW TO CARRY THAT AT THIS POINT. HIGH PRESSURE THEN BEGINS TO
BUILD IN AND CLEAR SKIES LATE TUESDAY INTO WEDNESDAY.
TEMPERATURE-WISE...GIVEN THAT WE WILL REMAIN ON THE WARM SIDE OF
THE OCCLUDED FRONT SATURDAY NIGHT...MINS SHOULD BE MILDER THAN MEX
WHICH IS BASED ON COOLER GFS MODEL. LOOKING AT SUNDAY MORNING MINS
IN THE MID 30S NORTHERN FORECAST AREA TO MID 40S SOUTHERN FORECAST
AREA. SAME TREND FOR SUNDAY DAY WITH MAX TEMPS JUST ABOVE MEX
GUIDANCE OR MID AND UPPER 40S. WITH COLD AIR FINALLY WRAPPING INTO
THE AREA SUNDAY NIGHT...MIN TEMPS MONDAY MORNING WILL REACH THE
LOWER AND MIDDLE 30S...AGAIN SEVERAL DEGREES WARMER THAN MEX
GUIDANCE WITH CLOUD COVER HELPING KEEP TEMPS UP A BIT. COOLER MAX
AND MINS TUESDAY AND WEDNESDAY AS CANADIAN HIGH INCREASES ITS
INFLUENCE SO LOWER 40 MAXS AND MINS DROPPING TO 20S AND LOWER 30S
AS CURRENTLY FORECAST LOOK GOOD.
&&
.AVIATION /DISCUSSION FOR 011800Z TAFS/...
CHALLENGING FORECAST WITH REGARDS TO CEILINGS THIS PERIOD AS SHALLOW
COLD ADVECTIVE CLOUD SHIELD OVER NRN INDIANA/IL HAD BEEN MOVING
SOUTHEAST AROUND 10 KTS UNTIL LAST HOUR WHEN MOVEMENT BECAME NEARLY
STATIONARY. THIS RECENT TREND IS MOST LIKELY RELATED TO GREATER
MIXING THAT HAS DEVELOPED DURING PEAK HEATING ON THE LEADING EDGE OF
THIS SHALLOW CLOUD MASS. AS DIURNAL MIXING WANES AFTER 21Z EXPECT TO
SEE CLOUD MASS MOVE SOUTH TO AT LEAST LAF/MIE AS PER 15Z RUC 950MB
RH FIELDS. GREATER UNCERTAINTY EXISTS WITH DEGREE OF LOW CLOUD
COVERAGE ACROSS REST OF TAF SITES TONIGHT. MAIN CONCERNS FOR LOW
CLOUD COVER TO MOVE INTO REST OF CENTRAL IN IS WARMER ANTECEDANT
GROUND TEMPERATURES AND WEAK CAA ABOVE THE INVERSION WHICH SHOULD
PRECLUDE ANY STRENGTHENING OF THE INVERSION OVERNIGHT. IN FACT THIS
CAA MAY ACTUALLY REDUCE THE INVERSION SUFFICIENTLY FOR THE LOW
CLOUDS TO CLEAR OUT COMPLETELY LATER THIS EVENING. ONCE MID-HIGH
CLOUD BANDS ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER KS/NE MOVE
AWAY FROM THE AREA AFTER 06Z MOSTLY CLEAR SKIES SHOULD LEAD TO THE
FORMATION OF LOWER VSBYS WITH SOME PATCHY GROUND FOG. CONF FOR FOG
IS NOT HIGH ENOUGH ATTM FOR SHOWING ANYTHING MORE THAN 1-3SM VIS AND
BR AT KLAF/KBMG AND KHUF TAFS WITH SLIGHTLY HIGHER VIS FCST AT KIND
OWING TO EFFECTS OF URBAN ENVIRONMENT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....TDUD
AVIATION...CROSBIE/TUCEK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1247 PM EST WED FEB 1 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW
&&
.SYNOPSIS...
A NORTH SOUTH AREA OF HIGH PRESSURE WILL DOMINATE INDIANA WEATHER
INTO FRIDAY. OVER THE WEEKEND LOW PRESSURE WILL MOVE TOWARD AND THEN
CROSS OUR STATE. HIGH PRESSURE IS EXPECTED TO RETURN MONDAY AND A
WEAK COLD FRONT IS FORECAST TO PASS TUESDAY. BY MIDWEEK HIGH
PRESSURE WILL BE BACK.
&&
.NEAR TERM /TONIGHT/...
BOTH SATELLITE OBSERVATIONS AND MODEL MOISTURE FIELDS SUPPORT PARTLY
CLOUDY TONIGHT. THIS LEAVES TEMPERATURES AS FORECAST PROBLEM.
MAV AND MET ARE CLOSE...BUT MET IS JUST SLIGHTLY COOLER. BASED ON
WHAT HAPPENED UPSTREAM LAST NIGHT I WILL USE THE MET.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MAIN PROBLEM IS WHEN PRECIPITATION WILL DEVELOP. ALL THE MODELS
AGREE WE ONLY HAVE TO WORRY ABOUT RAIN.
NAM...AND ASSOCIATED MET...BRING IN RAIN FASTER THAN GFS AND MAV. I
GOING TO UAW THE MAV. LATEST NAM IS NOT VERY CONSISTENT WITH ITS OWN
PREVIOUS RUN...OR THE SREF. THIS SUGGESTS IT IS AN OUTLIER.
FRIDAY NIGHT AND SATURDAY ALL MODELS PUT AT LEAST SOME QPF
EVERYWHERE IN THE CWA. IN MOST PLACES WILL USE LIKELY. EXCEPTION IS
THE EXTREME NORTHEAST FRIDAY NIGHT WHERE I WILL TAKE THE RELATIVELY
LOW POPS TO A HIGH CHANCE.
MAV HAS BEEN DOING WELL WITH TEMPERATURES LATELY. WILL USE THAT
THROUGH FRIDAY NIGHT WITH LITTLE CHANGE. SATURDAY MEX HIGHS ARE
ABOVE THE GFS HIGHS FROM THE MEN. SPLIT BETWEEN MEN HIGHS AND MEN
AVERAGES LOOKS BETTER TO ME GIVEN RAIN IS FORECAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SAME OLD STORY AS THE MAIN CHALLENGE WITH THE EXTENDED REVOLVES
MODEL TO MODEL AND RUN TO RUN CONSISTANCY REGARDING STRENGTH AND
POSITIONING OF THE KEY SURFACE AND UPPER PLAYERS AND HENCE THEIR QPF
FIELDS. THE 00Z GFS HOWEVER IS CONTINUING THE TREND OF BEING MUCH
FASTER AND WEAKER WITH AN UPPER LOW THAT THE GFS MOVES TO EASTERN
ILLINOIS BY 12Z SUNDAY BEFORE IT GETS ABSORBED IN AN UPPER TROUGH
THAT EXTENDS SOUTHWEST FROM THE CANADIAN MARITIMES. MEANWHILE...THE
00Z GFS ENSEMBLE MEMBERS ARE NO WHERE NO CONVERGING AN ANY SURFACE
OR UPPER FEATURES AFTER SATURDAY. THE 00Z GEM AND ECMWF RUNS ARE
STRONGER AND MUCH SLOWER WITH THE AFOREMENTIONED UPPER LOW DUE TO
SHARP RIDGING ACROSS THE UPPER OHIO VALLEY. WILL LEAN TOWARDS THE
GEM AS IT IS CLOSER TO THE ECMWF BUT YET NOT QUITE AS SLOW. THIS
ALSO SEEMS TO BE WHAT THE CENTRAL INITIALIZATION IS HINTING AT AND
CLOSE TO WHAT THE HEMISPHERIC DISCUSSION IS IMPLYING.
HOWEVER...UNTIL THE MODELS SHOW SOME BETTER CONSISTANCY AND
CONVERGENCE...CONFIDENCE ON TIMING...COVERAGE AND PRECIPITATION TYPE
THIS WEEKEND AND EARLY NEXT WEEK CONTINUES TO BE ON THE LOW SIDE.
STILL...GENERAL TREND SEEMS TO BEST FIT THE 00Z GEM WHICH BRINGS A
SURFACE LOW NORTHEAST ACROSS NORTH CENTRAL INDIANA ON SUNDAY WITH
THE UPPER LOW TRAILING ACROSS ROUGHLY THE SAME PATH MONDAY MORNING
BEFORE BEING ABSORBED IN THE NORTHEASTERN TROUGH. LOOKING AT
CRITICAL THICKNESSES...IT LOOKS LIKE MOSTLY A RAIN EVENT WITH THE
BEST CHANCES SATURDAY AND SATURDAY NIGHT AND THEN BECOMING DRY BY
MONDAY. WILL HOWEVER THROUGH IN A MIX ACROSS NORTHERN COUNTIES
OVERNIGHT SATURDAY NIGHT INTO SUNDAY MORNING ACROSS OUR NORTHERN
COUNTIES AND SUNDAY NIGHT ACROSS ALL BUT THE FAR SOUTHERN COUNTIES
BASED ON FORECASTED OVERNIGHT TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 011800Z TAFS/...
CHALLENGING FORECAST WITH REGARDS TO CEILINGS THIS PERIOD AS SHALLOW
COLD ADVECTIVE CLOUD SHIELD OVER NRN INDIANA/IL HAD BEEN MOVING
SOUTHEAST AROUND 10 KTS UNTIL LAST HOUR WHEN MOVEMENT BECAME NEARLY
STATIONARY. THIS RECENT TREND IS MOST LIKELY RELATED TO GREATER
MIXING THAT HAS DEVELOPED DURING PEAK HEATING ON THE LEADING EDGE OF
THIS SHALLOW CLOUD MASS. AS DIURNAL MIXING WANES AFTER 21Z EXPECT TO
SEE CLOUD MASS MOVE SOUTH TO AT LEAST LAF/MIE AS PER 15Z RUC 950MB
RH FIELDS. GREATER UNCERTAINTY EXISTS WITH DEGREE OF LOW CLOUD
COVERAGE ACROSS REST OF TAF SITES TONIGHT. MAIN CONCERNS FOR LOW
CLOUD COVER TO MOVE INTO REST OF CENTRAL IN IS WARMER ANTECEDANT
GROUND TEMPERATURES AND WEAK CAA ABOVE THE INVERSION WHICH SHOULD
PRECLUDE ANY STRENGTHENING OF THE INVERSION OVERNIGHT. IN FACT THIS
CAA MAY ACTUALLY REDUCE THE INVERSION SUFFICIENTLY FOR THE LOW
CLOUDS TO CLEAR OUT COMPLETELY LATER THIS EVENING. ONCE MID-HIGH
CLOUD BANDS ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER KS/NE MOVE
AWAY FROM THE AREA AFTER 06Z MOSTLY CLEAR SKIES SHOULD LEAD TO THE
FORMATION OF LOWER VSBYS WITH SOME PATCHY GROUND FOG. CONF FOR FOG
IS NOT HIGH ENOUGH ATTM FOR SHOWING ANYTHING MORE THAN 1-3SM VIS AND
BR AT KLAF/KBMG AND KHUF TAFS WITH SLIGHTLY HIGHER VIS FCST AT KIND
OWING TO EFFECTS OF URBAN ENVIRONMENT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....MK
AVIATION...CROSBIE/TUCEK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1244 PM EST WED FEB 1 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A COLD FRONT WILL BE EXITING THE AREA EARLY THIS MORNING...WITH
HIGH PRESSURE MOVING IN BEHIND IT. THE HIGH WILL REMAIN ACROSS THE
AREA UNTIL FRIDAY. FOR THE WEEKEND...UPPER AND SURFACE LOWS WILL
MOVE THROUGH THE REGION...BRINGING ANOTHER ROUND OF PRECIPITATION.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE SLIGHT ADJUSTMENTS TO FORECAST. LOW CLOUD DECK PUSHING
SOUTH FROM NRN ILLLINOIS AND INDIANA WILL MOVE INTO OUR NORTHERN
COUNTIES THIS AFTERNOON ENDING ANY KIND OF WARM UP. ALSO ADJUSTED
SKIES TO BE MORE CLOUDY THERE.
FURTHER SOUTH ALONG AND SOUTH OF I-70 CORRIDOR TEMPS HAVE WARMED
NICELY ALREADY REACHING AT OR ABOVE MOS GUIDANCE FORCAST HIGHS SO
HAVE ADJUSTED TEMPS UPWARD A DEGREE OR TWO IN THESE LOCATIONS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
FOCUS IS ON CHANCES FOR RAIN DURING THE PERIOD. STILL DISAGREEMENT
WITH HOW THE WEEKEND STORM SYSTEM WILL COME TOGETHER. THE TREND
HAS BEEN FOR A SLOWER ARRIVAL OF PRECIPITATION...SO SHIED AWAY
FROM THE FASTER NAM LATER IN THE PERIOD. OTHERWISE STUCK WITH A
BLEND.
AN UPPER WAVE WILL ALLOW A SURFACE LOW TO FORM ALONG THE FRONT TO
OUR SOUTH TONIGHT. AT THE MOMENT IT STILL APPEARS THAT THE
MOISTURE AND FORCING ASSOCIATED WITH THE LOW WILL REMAIN TO OUR
SOUTH...SO CONTINUED A DRY FORECAST TONIGHT. THE SYSTEM WILL KEEP
ENOUGH CLOUDS AROUND FOR PARTLY CLOUDY SKIES.
HIGH PRESSURE WILL THEN KEEP DRY AND MILD CONDITIONS ACROSS THE
AREA THURSDAY INTO FRIDAY...ALTHOUGH CLOUDS WILL INCREASE ON
FRIDAY AHEAD OF THE WEEKEND SYSTEM.
THAT WEEKEND SYSTEM SHOULD BE CLOSE ENOUGH FOR CHANCES OF
PRECIPITATION FRIDAY NIGHT...WITH THE HIGHEST POPS ACROSS THE
SOUTHWEST FORECAST AREA CLOSER TO THE SYSTEM. WITH THE UNCERTAINTY
AND GOING SLOWER THAN THE NAM YIELDED A FORECAST VERY SIMILAR TO
CONTINUITY WITH PREVIOUS FORECAST.
MAV MOS LOOKS PRETTY GOOD FOR TEMPERATURES THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SAME OLD STORY AS THE MAIN CHALLENGE WITH THE EXTENDED REVOLVES
MODEL TO MODEL AND RUN TO RUN CONSISTANCY REGARDING STRENGTH AND
POSITIONING OF THE KEY SURFACE AND UPPER PLAYERS AND HENCE THEIR QPF
FIELDS. THE 00Z GFS HOWEVER IS CONTINUING THE TREND OF BEING MUCH
FASTER AND WEAKER WITH AN UPPER LOW THAT THE GFS MOVES TO EASTERN
ILLINOIS BY 12Z SUNDAY BEFORE IT GETS ABSORBED IN AN UPPER TROUGH
THAT EXTENDS SOUTHWEST FROM THE CANADIAN MARITIMES. MEANWHILE...THE
00Z GFS ENSEMBLE MEMBERS ARE NO WHERE NO CONVERGING AN ANY SURFACE
OR UPPER FEATURES AFTER SATURDAY. THE 00Z GEM AND ECMWF RUNS ARE
STRONGER AND MUCH SLOWER WITH THE AFOREMENTIONED UPPER LOW DUE TO
SHARP RIDGING ACROSS THE UPPER OHIO VALLEY. WILL LEAN TOWARDS THE
GEM AS IT IS CLOSER TO THE ECMWF BUT YET NOT QUITE AS SLOW. THIS
ALSO SEEMS TO BE WHAT THE CENTRAL INITIALIZATION IS HINTING AT AND
CLOSE TO WHAT THE HEMISPHERIC DISCUSSION IS IMPLYING.
HOWEVER...UNTIL THE MODELS SHOW SOME BETTER CONSISTANCY AND
CONVERGENCE...CONFIDENCE ON TIMING...COVERAGE AND PRECIPITATION TYPE
THIS WEEKEND AND EARLY NEXT WEEK CONTINUES TO BE ON THE LOW SIDE.
STILL...GENERAL TREND SEEMS TO BEST FIT THE 00Z GEM WHICH BRINGS A
SURFACE LOW NORTHEAST ACROSS NORTH CENTRAL INDIANA ON SUNDAY WITH
THE UPPER LOW TRAILING ACROSS ROUGHLY THE SAME PATH MONDAY MORNING
BEFORE BEING ABSORBED IN THE NORTHEASTERN TROUGH. LOOKING AT
CRITICAL THICKNESSES...IT LOOKS LIKE MOSTLY A RAIN EVENT WITH THE
BEST CHANCES SATURDAY AND SATURDAY NIGHT AND THEN BECOMING DRY BY
MONDAY. WILL HOWEVER THROUGH IN A MIX ACROSS NORTHERN COUNTIES
OVERNIGHT SATURDAY NIGHT INTO SUNDAY MORNING ACROSS OUR NORTHERN
COUNTIES AND SUNDAY NIGHT ACROSS ALL BUT THE FAR SOUTHERN COUNTIES
BASED ON FORECASTED OVERNIGHT TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 011800Z TAFS/...
CHALLENGING FORECAST WITH REGARDS TO CEILINGS THIS PERIOD AS SHALLOW
COLD ADVECTIVE CLOUD SHIELD OVER NRN INDIANA/IL HAD BEEN MOVING
SOUTHEAST AROUND 10 KTS UNTIL LAST HOUR WHEN MOVEMENT BECAME NEARLY
STATIONARY. THIS RECENT TREND IS MOST LIKELY RELATED TO GREATER
MIXING THAT HAS DEVELOPED DURING PEAK HEATING ON THE LEADING EDGE OF
THIS SHALLOW CLOUD MASS. AS DIURNAL MIXING WANES AFTER 21Z EXPECT TO
SEE CLOUD MASS MOVE SOUTH TO AT LEAST LAF/MIE AS PER 15Z RUC 950MB
RH FIELDS. GREATER UNCERTAINTY EXISTS WITH DEGREE OF LOW CLOUD
COVERAGE ACROSS REST OF TAF SITES TONIGHT. MAIN CONCERNS FOR LOW
CLOUD COVER TO MOVE INTO REST OF CENTRAL IN IS WARMER ANTECEDANT
GROUND TEMPERATURES AND WEAK CAA ABOVE THE INVERSION WHICH SHOULD
PRECLUDE ANY STRENGTHENING OF THE INVERSION OVERNIGHT. IN FACT THIS
CAA MAY ACTUALLY REDUCE THE INVERSION SUFFICIENTLY FOR THE LOW
CLOUDS TO CLEAR OUT COMPLETELY LATER THIS EVENING. ONCE MID-HIGH
CLOUD BANDS ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER KS/NE MOVE
AWAY FROM THE AREA AFTER 06Z MOSTLY CLEAR SKIES SHOULD LEAD TO THE
FORMATION OF LOWER VSBYS WITH SOME PATCHY GROUND FOG. CONF FOR FOG
IS NOT HIGH ENOUGH ATTM FOR SHOWING ANYTHING MORE THAN 1-3SM VIS AND
BR AT KLAF/KBMG AND KHUF TAFS WITH SLIGHLY HIGHER VIS FCST AT KIND
OWING TO EFFECTS OF URBAN ENVIRONMENT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...TUCEK
SHORT TERM...50
LONG TERM....MK
AVIATION...CROSBIE/TUCEK
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1239 PM EST WED FEB 1 2012
.AVIATION...
SHALLOW MOIST LAYER FROM SFC-1200FT TRAPPED BENEATH A STRONG
INVERSION OVER THE REGION AS EVIDENCED BY NEARBY MORNING UPPER
AIR SOUNDINGS AND TAMDAR. LATEST VISIBLE SATELLITE IMAGERY
INDICATES STRATUS SEWD PROGRESS SLOWING JUST SOUTH OF FWA AND SOME
HOLES DEVELOPING UPSTREAM OVER WI/NE IL. GIVEN WK FLOW AND
EXTENT OF CLOUD SHIELD UPSTREAM...CONTD WITH BKN MVFR CIGS IN THE TAFS
UNTIL THIS EVE... THOUGH CONFIDENCE ON WHEN LOW CLOUDS WILL BREAK
OUT AT THE TERMINALS IS NOT HIGH ATTM. MOIST LOW LEVELS AND LIGHT
WINDS SHOULD PERSIST OVERNIGHT SO EXPECT SOME RADIATIONAL COOLING
FOG TO DEVELOP TOWARD DAYBREAK THURSDAY LOWERING VISIBILITY INTO
MVFR RANGE.
&&
.PREV DISCUSSION... /ISSUED 1047 AM EST WED FEB 1 2012/
UPDATE...
LARGE AREA OF STRATUS OVER THE UPR GRTLKS CONTG TO SAG SEWD ACROSS
OUR CWA THIS MORNING. USING RUC 925MB RH FIELDS AND LATEST VISIBLE
SATELLITE IMAGERY EXPECT THIS CLOUD DECK WILL IMPACT OUR ENTIRE CWA
THIS AFTN... THUS UPDATED FCST TO INCREASE CORRESPONDING CLOUD COVER GRIDS.
STRATUS SHOULD HOLD TEMPS DOWN A BIT THIS AFTN AND LOWERED HIGHS
SLIGHTLY MOST OF THE CWA. CLOUDS COULD LIMIT COOLING TONIGHT AS
WELL BUT HELD OFF MAKING ANY CHANGES IN THAT REGARD ATTM.
SHORT TERM...
TODAY THROUGH THURSDAY NIGHT
SFC COLD FRONT AND THE ASSOCIATED MID LEVEL IMPULSE WILL CONTINUE TO
EXIT THE REGION WITH COOLER AIR ADVECTING INTO THE REGION. FAIRLY
QUIET WEATHER IN THE PERIOD...WITH CONTINUED PROGRESSIVE FLOW AND A
DEVELOPING SPLIT PER A DIGGING SW CONUS TROUGH. ANOTHER FAST MOVING
NORTHERN STREAM WAVE EXPECTED INTO THE GREAT LAKES TONIGHT...WITH
WEAK RIDGING AT THE SFC. MILD THERMAL FIELDS PER PAC ORIGIN FLOW
WILL SUPPORT TEMPS ABOVE NORMAL IN THE PERIOD...WITH COOLER
CONDITIONS TODAY ON THE BACKSIDE OF THE DEPARTING IMPULSE. MAIN
CONCERN TODAY WILL BE HIGH TEMPS ACROSS THE NORTHERN THIRD AS
BACKSIDE IMPULSE STRATUS GRAZES THE AREA. GENERAL CONSENSUS IN
GUIDANCE IS FOR THE BULK OF THE CLOUDS TO REMAIN NORTH OF THE
FA...WITH THE NORTHERN THIRD BEING GRAZED THIS MORNING. DIURNAL
MIXING SHOULD SUPPORT SCATTERING OF THE STRATO CU DECK BY LATE
MORNING/EARLY AFTERNOON. HIGHS WILL BE COOLER THAN YESTERDAY...WITH
MOST AREAS ONLY SEEING 40S...SOME LOWER 50S POSSIBLE FAR SOUTH.
NORTHERN PLAINS IMPULSE /EVIDENT IN WATER VAPOR/ WILL ADVECT INTO
THE GREAT LAKES OVERNIGHT...SUPPORTING INCREASED MID/HIGH CLOUD.
OVERALL WEAK FORCING WITH LIMITED LL MOISTURE WILL SUPPORT LIGHT LL
FLOW...WITH DRY CONDITIONS OVERNIGHT. INCREASED CLOUD COVER WILL
KEEP TEMPS UP SOME...WITH LOWER 30S TO UPPER 20S EXPECTED. SMALL
THERMAL FIELD UNDULATION ASSOCIATED WITH THIS WAVE WILL SUPPORT A
REINFORCEMENT OF THERMAL FIELDS WITH HIGHS GENERALLY AROUND TODAY/S
VALUES...SLIGHTLY WARMER SW HALF GIVEN ENSUING WAA BY LATER IN THE
DAY PERIOD THUR. MOSTLY CLEAR SKIES AND LIGHT WINDS EXPECTED THUR
NIGHT...WITH MODERATE RADIATIONAL COOLING SUPPORTING LOWS IN THE
UPPER 20S MOST PLACES. A FEW HEIGHT RISE CIRRUS ARE POSSIBLE.
LONG TERM...
COMPLICATED AND VARIABLE LONG TERM FORECAST AS MODELS REMAIN IN FLUX
WITH HANDLING WEEKEND SYSTEM OVER CENTRAL CONUS. PREFERENCE AT THIS
TIME LIES TOWARD THE ECMWF WITH STRONG WEIGHT TOWARD CONSISTENCY AS
DETAILS AND EVEN LARGER SCALE FLOW STILL IN QUESTION WITH UPCOMING
SYSTEM. WHAT DOES LOOK MORE CERTAIN ARE TEMPERATURES THROUGH MOST OF
THIS LONG TERM PERIOD REMAINING ABOVE NORMAL. THERE ARE SIGNS
POINTING TOWARD COLDER...MORE SEASONABLE TEMPERATURES JUST BEYOND
THE DAY 7 PERIOD.
WATER VAPOR TELLS THE STORY TODAY WITH STRONG NORTH PACIFIC JET AND
SEVERAL STRONG SHORT WAVES BEGINNING TO BUCKLE THE FLOW OVER THE
NORTH PACIFIC. PNA TELECONNECTIONS SHOW TREND TOWARD POSITIVE PHASE
FROM 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL WITH GOOD CORRELATION
THROUGH THE 7 TO 10 DAY FORECAST PERIOD. AO INDICES ALSO TRENDING
STRONGLY NEGATIVE SUPPORTING GREATER AMPLIFICATION OF UPSTREAM
PATTERN AND POTENTIAL COLDER TEMPERATURES MID TO END OF NEXT WEEK.
THESE FACTORS SHOULD ALLOW FOR STRONG RIDGE TO DEVELOP IN WESTERN
CONUS WHICH WOULD ALSO ALLOW INCOMING ENERGY TO DEEPEN ACROSS THE
PLAINS BY END OF THIS WEEK. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON
THIS SCENARIO THROUGH FRIDAY WITH CLOSED LOW DEVELOPING IN CENTRAL
CONUS. MODELS REALLY BEGIN TO DIVERGE THIS WEEKEND WITH HOW THIS LOW
WILL EVOLVE AND EVENTUALLY EJECT OUT OF CENTRAL CONUS AND THE
ASSOCIATED IMPACTS AND TIMING FOR OUR AREA. DIFFERENCES APPEAR TO BE
RELATED TO TIMING OF A NORTHERN STREAM SHORT WAVE AND LOCATION OF
UPPER LOW BY END OF WEEKEND. GFS AS EXPECTED IS FARTHER EAST WITH
UPPER LOW AND ALLOWS NORTHERN WAVE TO PICK UP CLOSED LOW AND BOTH
EJECT SOUTHEAST OUT OF THE AREA SUNDAY NIGHT. MEANWHILE...ECMWF
SOLUTION APPEARS TO BE SLOWER WITH UPPER LOW DRIFTING EAST AND
ALLOWS NORTHERN STREAM WAVE TO PASS THROUGH GREAT LAKES LEAVING
BEHIND THE LOW IN THE PLAINS TO CONTINUE WITH A SLOWER MOVEMENT
NORTHEAST. GIVEN TYPICAL GFS BIAS WITH BEING TOO FAR EAST WITH
CLOSED UPPER LOWS AND ECMWF SUPERIOR PERFORMANCE DURING THE WINTER
PREFERENCE LIES TOWARD THE ECMWF. HOWEVER...FOR CONSISTENCY AND TO
AVOID FLIP FLOPPING FORECAST DUE TO HIGH UNCERTAINTY...HAVE REMAINED
FAIRLY CLOSE TO ALL BLEND INIT FOR THIS PACKAGE. THIS REFLECTS BEST
CHANCES FOR PCPN LATE FRIDAY NIGHT AND SATURDAY IN SOUTH AS INITIAL
SURGE OF MOISTURE AND WEAK SHORT WAVE APPROACH THE AREA. LOW CHANCE
POPS CONTINUED THROUGH SUNDAY WITH ECMWF SHOWING WEAK LIFT AND
MOISTURE FOR POSSIBLE SHOWERS. REMAINDER OF FORECAST WAS LEFT
UNCHANGED WITH NO APPRECIABLE WEATHER MENTION GIVEN HIGH UNCERTAINTY
AND LOW PROBABILITY AT THIS TIME.
REGARDLESS OF SOLUTIONS TEMPERATURES WILL REMAIN ABOVE NORMAL
THROUGH MOST OF THE PERIOD...AND WELL ABOVE NORMAL THROUGH THIS
WEEKEND. TEMPERATURES LIKELY TO TREND BACK CLOSER TO NORMAL BY DAY 7
WITH ECMWF SOLUTION. MUCH COLDER AIR LOOKS TO STAGE TO OUR NORTH BY
DAY 7 WITH POSSIBILITY OF REACHING US BY MID TO LATE NEXT WEEK.
TELECONNECTION INDICES FAVORING THIS BUT NORTH ATLANTIC OSCILLATION
FORECAST CONTINUES TO BE NEAR NEUTRAL THROUGH THE WEEK 2 PERIOD
SUGGESTING NO BLOCKING DOWNSTREAM TO HOLD COLD AIR IN PLACE. THIS IS
WELL OUTSIDE THE CURRENT FORECAST PERIOD BUT SOMETHING TO WATCH
GIVEN POSITIVE PNA AND NEGATIVE AO TRENDS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...LASHLEY
AVIATION...JT
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1210 PM CST WED FEB 1 2012
.AVIATION...
STRATUS AND FOG WITH AREAS OF DENSE FOG AND IFR TO VLIFR CONDITIONS
CONTINUE TO BLANKET THE KCID... KDBQ AND KMLI TERMINALS AND HOLDING
JUST NORTH OF KBRL. WITH TRAPPING LLVL INVERSION AND LITTLE
SENSIBLE MIXING WIND WILL EXTEND THESE CONDITIONS INTO THE EVENING.
SOME BRIEF WEST NORTHWEST BOUNDARY LAYER WIND PICK UP LATE
AFTERNOON INTO EARLY EVENING MAY TRY AND IMPROVE CIGS ABOVE
500-1000 FT AGL AND VSBYS TO 2-4SM AT CID AND MLI...BUT CONFIDENCE
ON THIS REMAIN LOWS AND MAY BE OPTIMISTIC THINKING. FEEL AREAS
WHERE STRATUS IS CURRENTLY ONGOING WILL LOWER INTO THE 1/2 TO
1/4SM VSBYS AGAIN TONIGHT BY 03Z AT MOST SITES WITH CIGS/VVS UNDER
500 FT AGL UNDER SLOW MOVING RIDGE. THAT/S IF EVEN THE SITES
IMPROVE LATER THIS AFTERNOON. EVEN IN AREAS THAT CLEAR OR IF BRL
REMAINS CLEAR THIS AFTERNOON AND EVENING...THESE AREAS MAY
RADIATIONALLY FOG BACK IN BY 05Z-06Z AT THE LATEST. HOPEFULLY EAST-
SOUTHEAST RETURN FLOW AFTER PASSING SFC RIDGE AXIS WILL BEGIN TO
MIX OUT ANY LINGERING FOG AND VERY LOW CLOUDS BY 15Z THU MORNING.
..12..
&&
.PREV DISCUSSION... /ISSUED 608 AM CST WED FEB 1 2012/
UPDATE...
STRATUS AND FOG CONTINUES TO ADVECT IN ON LLVL NORTHWEST FLOW. SEVERAL
SITES HAVE GONE DOWN AT OR BELOW 1/4SM ESPECIALLY ON THE IA SIDE
OF RIVER ALONG/N OF I-80. HAVE THEREFORE ISSUED DENSE FOG ADVISORY FOR
THIS AREA UNTIL 16Z. GIVEN STRENGTH OF INVERSION AND STRATUS COULD SEE
DENSE FOG PERSIST INTO THE AFTN.
PREV DISCUSSION... /ISSUED 320 AM CST WED FEB 1 2012/
SYNOPSIS...
EARLY AM SFC ANALYSIS PLACES LOW NORTH OF LAKE HURON JUST TO NORTH OF
SUDBURY ONTARIO. COLD FRONT TRAILS FROM THE LOW THROUGH CENTRAL IN
INTO NORTH TX. WEAK RIDGING EXTENDS FROM CENTRAL PLAINS INTO THE
UPPER MIDWEST. STRATUS WHICH FORMED OVER THE DAKOTAS INTO WESTERN MN
YSTDY CONTINUES TO EXPAND AND SURGE SOUTHEAST AIDED BY COLD
ADVECTION OVER EXISTING SNOWPACK NORTH AND MOIST BL FROM SNOW MELT.
LATEST 11-3.9 MICRON SATL IMAGERY SHOWS LEADING EDGE OF THE STRATUS
FROM KVTI TO KFEP MOVING SOUTHEAST AT AROUND 12 KTS. SOME FOG ALSO
OCCURRING WITH STRATUS... BUT VSBYS GENERALLY AT OR ABOVE 3SM ATTIM.
SHORT TERM...TODAY AND TONIGHT...
CLOUD TRENDS WITH IMPACT ON TEMPS... AND FOG POTENTIAL MAIN FCST
CONCERNS.
MOST MODELS STRUGGLING TO CAPTURE CURRENT STRATUS DECK... EXCEPT
FOR LATEST RUNS OF HRRR AND RUC BACKUP MODELS VIA ESRL. THESE
MODELS GENERALLY SUPPORT CONTINUED SOUTHEAST MOVEMENT THROUGH
DAYBREAK WITH MOST OF AREA NORTH OF HWY 34 BLANKETED BY THE STRATUS
BY MID AM. ONE CONCERN IS THAT RECENT SATL TRENDS SEEM TO SHOW THE
STRATUS CONTINUING TO SLOW... AND MAY BE DUE IN PART TO OUTRUNNING
THE SNOW FIELD AND MORE MOIST BL FROM SNOW MELT PAST 24 HRS NORTH OF
HWY 30. JUST WHERE LEADING EDGE OF STRATUS RESIDES BY MID AM
LIKELY TO BE IT FOR MOVEMENT AS STRENGTHENING SOLAR INSOLATION
LIKELY TO IMPEDE FURTHER PROGRESS. OF COURSE WHERE THIS ENDS UP WILL
BE HUGE FACTOR ON HIGH TEMPS. ANOTHER FACTOR IS EVOLUTION OF THE
EXISTING STRATUS THIS AFTN INTO TNGT AND WHETHER ANY CLEARING CAN
TAKE PLACE. LATEST HRRR AND RUC BACKUP MODELS DO SUPPORT DECREASE IN
STRATUS THIS AFTN... WITH HRRR SLIGHTLY SLOWER AND NOT UNTIL MID AFTN.
0412Z AMDAR ASCENT SOUNDING FROM KMSP SIMILAR TO 00Z MPX RAOB AND
SHOWS MOIST LAYER 500-1000 FT THICK... WITH MOISTURE LINGERING INTO
STRONG INVERSION AND NOT JUST BELOW IT. THIS IS A CONCERN AS IS FACT
THAT AREA WILL RESIDE IN WEAK SYNOPTIC SCALE FLOW... THUS MIXING WILL
BE LIMITED TO TAP DRY AIR ALOFT AND PROMOTE EROSION. THEREFORE
FAVOR SLOWER CLEARING TRENDS FROM HRRR... BUT ALSO MUST WONDER IF THE
STRATUS DOESNT DISSIPATE THIS AFTN WHAT WOULD PROMOTE EVACUATION TNGT.
SOME MODELS DO SHOW WARMING IN 925 MB LAYER TNGT AS FLOW IN THIS
LAYER BECOMES WESTERLY IN ASSOCIATION WITH CLIPPER TYPE SYSTEM PASSING
WELL NORTH INTO NORTHERN MN AND WI. THIS MAY BE ENOUGH TO CHEW AWAY AT
ANY RESIDUAL STRATUS... AND FOR NOW SKY COVER GRIDS EVOLVING TO MORE
OPTIMISTIC IN TIME. AS FOR TDY... WILL BE HEAVILY NOWCASTING CURRENT
STRATUS DECK AND USING HRRR AND RUC BACKUP MODELS FOR TRENDS. FOR NOW
WILL GO WITH IDEA OF STRATUS NEARING HWY 34 BY MID AM THEN LINGERING
INTO AFTN WITH SLOW EROSION THROUGH THIS EVE. ALL AREAS TDY WILL BE
COOLER... BUT TEMPS STILL ABOVE NORMAL. COOLEST READINGS BENEATH THE
STRATUS WHERE TEMPS COULD STRUGGLE TO 40 DEGS IF THEY HOLD ALL DAY.
OTRW... WARMEST READINGS SOUTH WHERE U40S TO L50S LOOK LIKELY WITH SOME
INCREASING HIGH CLOUDINESS. IN SHORT... AS CLOUDS GO... SO GO THE TEMPS.
WITH SOME UNCERTAINTY ON CLOUD TRENDS TNGT STAYED NEAR GUIDANCE BLEND
ON LOW TEMPS. FOG A POSSIBILITY TNGT WITH LIGHT BL FLOW AND LLVL MOISTURE
ESPECIALLY IN THOSE AREAS THAT SEE CLEARING LATE DAY INTO EARLY EVE.
IF STRATUS LINGERS WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG FORM ON
WESTERN EDGE. TOO UNCERTAIN THOUGH FOR ANY MENTION ATTIM BUT PASS ON THE
CONCERN TO DAY CREW. ..05..
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
DRY AND QUIET CONDITIONS WILL BE SEEN THURS/THURS NIGHT AS HIGH
PRESSURE MOVES ACROSS THE AREA. TEMPERATURES WILL CONTINUE TO
AVERAGE ABOVE NORMAL.
STARTING FRIDAY...THINGS BECOME MORE INTERESTING. DPROG/DT CONTINUES
TO SHOW A SUBTLE SLOWING OF THE RESPECTIVE MODEL SOLUTIONS. HIGH
PRESSURE FROM THE NORTHERN PLAINS INTO THE GREAT LAKES CONTINUES TO
TREND STRONGER INDICATING A DEEPER FETCH OF DRY EASTERLY FLOW. THE
MAJOR UNKNOWN IS THE ENERGY CURRENTLY ENTERING THE GULF OF ALASKA
AND HOW IT WILL KICK OUT THE CUT OFF LOW IN THE PLAINS. ALL MODELS
CONTINUE TO SHOW VARIABILITY WHICH IS TRACEABLE TO HOW THE
RESPECTIVE ENERGIES INTERACT WITH EACH OTHER.
SO...FRIDAY MORNING WILL BE DRY WITH INCREASING CLOUDS. ALL MODELS
SHOW STRONG FORCING AND LOW CONDENSATION PRESSURE DEFICITS FROM
MISSOURI INTO CENTRAL IOWA ALONG WITH A GOOD MOISTURE FEED. OVER THE
CWFA...ALL MODELS SHOW EASTERLY FLOW FROM THE SFC UP THROUGH 850MB.
THUS PRECIP WILL NOT BE FAR AWAY FROM THE FAR SOUTHWEST PART OF THE
CWFA BY MID DAY FRIDAY.
FRIDAY AFTERNOON...THE DEEP AND DRY EASTERLY FLOW CONTINUES ACROSS
THE CWFA. BY MID TO LATE AFTERNOON 850-700MB CONDENSATION PRESSURE
DEFICITS COLLAPSE OVER ROUGHLY THE SOUTHWEST QUARTER OF THE CWFA
WITH GOOD FORCING. THE MOISTURE FEED BEGINS MOVING INTO THE CWFA AS
WELL. THE HEAVY RAIN AND LIFT TOOLS SHOW THE STRONG CONVERGENCE IS
THERE BUT WEAKENING WITH TIME. THUS RAIN SHOULD DEVELOP/MOVE INTO
THE CWFA IN AN ARCING LINE FROM NORTHERN KEOKUK COUNTY TO ROUGHLY
THE HANCOCK/MCDONOUGH BORDER BY EARLY EVENING. THE HIGHEST POPS WILL
BE IN THE FAR SOUTHWEST CORNER OF THE CWFA.
THE FACT THAT THE OVERALL CONVERGENCE IS WEAKENING WITH TIME PER THE
LIFT AND HEAVY RAIN TOOLS INDICATES THAT ANY CONVECTION THAT IS
OCCURRING ACROSS MISSOURI WILL BE STRATIFYING OUT AS IT MOVES INTO
THE CWFA. THUS ONLY RAIN IS EXPECTED THROUGH SUNSET.
FRIDAY NIGHT...THE WAA AND MOISTURE FINALLY WINS OUT OVER THE DRY
AIR BUT THE IMMEDIATE HWY 20 CORRIDOR WILL LIKELY REMAIN DRY THROUGH
MIDNIGHT. THE DRY EASTERLY FLOW WILL ALLOW EVAPORATIVE COOLING TO
OCCUR ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD. THIS
EVAPORATIVE COOLING WILL LIKELY RESULT IN A RAIN/SNOW MIX THAT
CHANGES OVER TO ALL SNOW IN THE HWY 20 CORRIDOR WITH ANY
ACCUMULATIONS BEING ONE HALF INCH OR LESS. THE HWY 30 CORRIDOR DOWN
TO ALMOST I-80 WILL LIKELY SEE A RAIN/SNOW MIX THAT DEVELOPS DURING
THE NIGHT.
SATURDAY ON...
MODEL CONSENSUS HAS LIKELY POPS FROM THE I-80 CORRIDOR ON SOUTH WITH
CHC POPS NORTH WHICH ARE LIKELY ON THE LOW SIDE. A RAIN/SNOW MIX
SHOULD BE ONGOING WITH SUNRISE OVER ROUGHLY THE NORTHERN 40 PERCENT
OF THE CWFA WITH RAIN ELSEWHERE. ANY MIX SHOULD CHANGE OVER TO A
VERY COLD RAIN AS THE DAY PROGRESSES. DYNAMIC COOLING COULD KEEP A
MIX GOING IN THE FAR NORTHWEST PART OF THE CWFA.
THE CONSENSUS GIVES CHC POPS SATURDAY NIGHT WITH SCHC POPS ON SUNDAY
AS ENERGY UPSTREAM KICKS THE STORM SYSTEM INTO THE EASTERN GREAT
LAKES. SUNDAY NIGHT THROUGH NEXT TUESDAY THE MODEL CONSENSUS HAS DRY
CONDITIONS ACROSS THE AREA AS NORTHWEST FLOW ALOFT DEVELOPS.
TEMPERATURES SATURDAY THROUGH TUESDAY SHOULD CONTINUE TO AVERAGE
ABOVE NORMAL BUT WILL BE MUCH CLOSER TO NORMAL SUNDAY THROUGH
TUESDAY. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-
JOHNSON-JONES-LINN-MUSCATINE-SCOTT.
IL...DENSE FOG ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR ROCK ISLAND.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
555 PM EST WED FEB 1 2012
.AVIATION...
//DISCUSSION...
RECENT MODEL GUIDANCE PROVIDING LITTLE ASSISTANCE IN DEFINING THE
CLOUD DETAILS FOR TONIGHT AND BEYOND...WITH RELIANCE THIS TAF
ISSUANCE LARGELY LEANING ON LATEST TRENDS IN SATELLITE AND
OBSERVATIONAL DATA. THE MOST RECENT DATA SET SUGGEST THE EXPANSIVE
MVFR STRATUS DECK NOW ENCOMPASSING ALL OF SOUTHEAST MICHIGAN WILL
STRUGGLE TO BUDGE THIS EVENING AS MIXING CEASES AND SUFFICIENT
MOISTURE REMAINS TUCKED BENEATH ESTABLISHED INVERSION LAYER. THIS
POINTS TOWARD LEANING MORE PESSIMISTIC IN CARRYING A PROLONGED MVFR
CEILING THROUGH THE NIGHT. NARROW POCKET OF CLEARING EMERGING
SOUTH/EAST OF DTW WILL BE WORTH MONITORING. SHOULD SOME LARGER BREAKS
IN THE DECK DEVELOP OVERNIGHT...THEN A WEAK GRADIENT WOULD SUPPORT A
BRIEF DIP IN VISIBILITY /4-6SM/ WITHIN A 10-14Z WINDOW.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE THAT CEILING WILL REMAIN BELOW 5000 FEET
TONIGHT. LOW CONFIDENCE ON THURSDAY.
&&
.PREV DISCUSSION...ISSUED 340 PM EST WED FEB 1 2012
SHORT TERM...THIS EVENING AND TONIGHT
HIGH PRESSURE SYSTEM OVER THE UPPER MISSISSIPPI VALLEY WILL
BUILD OVER THE GREAT LAKES OVERNIGHT WITH THE RIDGE AXIS OVERHEAD BY
AROUND 12Z. WITH THE PRESSURE GRADIENT ALREADY RELAXING...WIND
SPEEDS ALREADY ON THE DECLINE WILL CONTINUE UNTIL THEY ARE LIGHT AND
VARIABLE BY MORNING. THE MAIN FORECAST CONCERN IS WITH CLOUD/FOG
POTENTIAL FOR THE OVERNIGHT. STRATUS DECK AROUND 3KFT MANAGED TO
FILL IN OVER ALL OF SE MI THIS MORNING EXTENDING BACK WEST INTO
IA/MN...UNDER THE NORTH SIDE OF THE RIDGE AXIS THAT WILL BE MOVING
OVERHEAD TONIGHT. EXPECT THIS LOW STRATUS DECK TO THIN OUT SOMEWHAT
THIS EVENING WHILE HIGHER CIRRUS CLOUDS THICKEN TONIGHT. RUC MODEL
SOUNDINGS AGREE WITH THIS THINKING THOUGH IT KEEPS LOW LEVEL
MOISTURE VALUES QUITE HIGH IN THE LOWEST 3KFT. THE NAM DOES ITS
USUAL AND IS EVEN MORE ROBUST WITH BOUNDARY LAYER SO LEANING MORE
TOWARD RUC. SO MODELS SHOW THERE IS POTENTIAL FOR THE STRATUS TO
LINGER LONGER THROUGH THE NIGHT. EVEN THOUGH MANY OF THE ASOS
STATIONS IN IA/MN/WI REPORTED FOG WITH VISIBILITY RESTRICTIONS DOWN
TO 2-4 MILES EARLY THIS MORNING...THE ABUNDANT CLOUD COVER WE WILL
HAVE IN PLACE SHOULD PREVENT MUCH FOG FORMATION IF ANY. RAISED MIN
TEMPS TONIGHT A DEGREE OR 2 TO ACCOUNT FOR THE THICKER CLOUDS.
LONG TERM...THURSDAY THROUGH NEXT WEDNESDAY
FORECAST CONTINUES TO LOOK FAIRLY QUIET DURING THE EXTENDED
PERIOD...AT LEAST FOR FEBRUARY. TEMPERATURES WILL CONTINUE TO RUN
ABOVE NORMAL INTO THE BEGINNING OF NEXT WEEK BEFORE A STRONG COLD
FRONT DROPS TEMPERATURES BACK CLOSER TO NORMAL NEXT WEDNESDAY.
UPPER SHORTWAVE OVER SOUTHERN MANITOBA THIS AFTERNOON WILL DROP DOWN
ACROSS THE NORTHERN GREAT LAKES THURSDAY. THIS SHOULD KEEP THE
SURFACE RIDGE INTACT OVER SOUTHEAST LOWER MICHIGAN...WHILE A WEAK
SURFACE TROUGH SLIDES ACROSS NORTHERN MICHIGAN IN RESPONSE. THINK
LIGHT SNOW SHOWERS WILL STAY NORTH OF THE AREA AND HAVE KEPT THE
FORECAST DRY...WITH THE MAIN IMPACT FROM THIS SHORTWAVE EXPECTED TO
BE AN INCREASE IN MID LEVEL MOISTURE OVER CENTRAL MICHIGAN. MODEL
FORECAST SOUNDINGS THROUGH THURSDAY NIGHT KEEP A SUBSIDENCE
INVERSION IN PLACE ACROSS SOUTHEAST MICHIGAN...GENERALLY BETWEEN
900-800MB. ALTHOUGH GFS/NAM DO NOT SHOW AN OVERABUNDANCE OF
LOW-LEVEL MOISTURE REMAINING TRAPPED IN THE LOWER LEVELS...DID LEAN
MORE PESSIMISTIC WITH THE SKY COVER FORECAST (MORE CLOUDS) THAN
MODELS SUGGEST GIVEN POOR MIXING AND LIGHT WEST TO NORTHWEST FLOW
OFF LAKE MICHIGAN. ASSUMING THERE IS A LOWER CLOUD DECK...WILL HAVE
TO SEE IF MID-LEVEL MOISTURE OVERRUNNING ANY MOISTURE TRAPPED
UNDERNEATH THE SUBSIDENCE INVERSION COULD SEED LOWER CLOUDS ACROSS
CENTRAL MICHIGAN...WHICH WOULD MAYBE PRODUCE SOME FLURRIES. GIVEN
THE EXPECTATION FOR MORE CLOUDS AND VERY LIGHT WINDS/POOR
MIXING...WENT ON THE COOL SIDE OF MOS GUIDANCE FOR HIGHS
THURSDAY...IN THE MID 30S TO LOW 40S.
THE RIDGE WILL THEN RESTRENGTHEN OVER THE CENTRAL GREAT LAKES
THURSDAY NIGHT AND FRIDAY...BEFORE ANOTHER UPPER SHORTWAVE DROPS
DOWN THROUGH THE CENTRAL GREAT LAKES FRIDAY NIGHT. GFS/NAM BRING A
WEAK FRONT DOWN ACROSS THE AREA WITH THIS FEATURE...BUT IT LOOKS
MOISTURE STARVED AND SHOULD DO LITTLE BUT INCREASE CLOUDS ONCE
AGAIN. NAM IS SLOWER WITH BOTH THE FRONT AND SOUTHWARD PROGRESS WITH
THIS WAVE ACROSS THE GREAT LAKES FRIDAY/FRIDAY NIGHT...AND HAVE
THEREFORE HEAVILY FAVORED THE OTHER MODELS WITH THE ARRIVAL OF
LOW-LEVEL MOISTURE AND PRECIPITATION LATE FRIDAY NIGHT INTO
SATURDAY. WITH THE SLOWER TIMING...NAM ALLOWS AN APPROACHING LOW
PRESSURE SYSTEM AND ASSOCIATED AREA OF DEFORMATION TO MAKE QUICKER
AND FURTHER INROADS INTO THE SOUTHERN GREAT LAKES.
REX BLOCK PATTERN WILL DEVELOP OVER THE WEST COAST BY FRIDAY...PER
STRONG CONSENSUS FROM FORECAST MODELS. THIS BLOCK WILL THEN VERY
SLOWLY MAKES IT WAY EAST INTO THE CENTRAL CONUS AND TOPPLE OVER THE
WEEKEND. MODELS REMAIN VERY DIVIDED ON HOW LONG IT WILL TAKE THE
UPPER LOW ON THE SOUTHERN END OF THE BLOCK TO LIFT UP INTO THE
SOUTHERN GREAT LAKES. SPREAD IS ANYWHERE FROM SATURDAY NIGHT (12Z
GFS) TO EARLY MONDAY (12Z GEM)...AND CONFIDENCE SURROUND TIMING OF
WEATHER IMPACTS FROM THIS FEATURE ARE VERY LOW. UKMET/GEM/EURO KEEP
THE SYSTEM FAR ENOUGH SOUTH OF THE AREA NOW TO SUPPORT A DRY
FORECAST THROUGH AT LEAST SATURDAY NIGHT. DID HOWEVER KEEP A SLIGHT
CHANCE FOR RAIN/SNOW NEAR THE OHIO BORDER SATURDAY AFTERNOON AND
OVERNIGHT...WITH LOW CHANCES FOR LIGHT SNOW SHOWERS BY SUNDAY NIGHT.
UPPER TROUGHING LOOKS TO BUILD OVER THE NORTHEASTERN PORTION OF
NORTH AMERICA AND THE GREAT LAKES TOWARDS THE MIDDLE OF THE
WEEK...WITH SEVERAL SHORTWAVE TROUGHS DROPPING DOWN ACROSS THE AREA
MONDAY THROUGH WEDNESDAY. GFS/EURO ALSO AGREE WITH A FAIRLY STRONG
COLD FRONT DROPPING DOWN THROUGH MICHIGAN ON TUESDAY (THOUGH THERE
REMAIN SLIGHT TIMING DIFFERENCES). THIS WOULD BRING A QUICK SHOT OF
SNOW SHOWERS AND DROP TEMPERATURES BACK DOWN TO NEAR NORMAL BY
WEDNESDAY.
MARINE...
HIGH PRESSURE OVER THE WESTERN GREAT LAKES WILL BUILD EASTWARD
OVERNIGHT WITH THE RIDGE AXIS ACROSS LAKE HURON BY THURSDAY MORNING.
THE PRESSURE GRADIENT HAS ALREADY WEAKENED SUBSTANTIALLY THROUGH THE
DAY ALLOWING WINDS TO DECREASE WITH MAX GUSTS REACHING 20 KNOTS OVER
THE OPEN WATERS OF LAKE HURON. WINDS AND WAVE WILL CONTINUE TO
DECREASE THROUGH THE NIGHT AS THE RIDGE AXIS DRAWS NEARER. THIS HIGH
PRESSURE SYSTEM WILL PRODUCE VERY FAVORABLE MARINE CONDITIONS INTO
THE WEEKEND. A LOW PRESSURE TROUGH WILL PASS THROUGH THE REGION ON
THURSDAY...THOUGH IT WILL BE VERY WEAK AND WILL MOST LIKELY NOT BE
ABLE TO PUT A DENT IN THE LARGER SCALE RIDGE IN PLACE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
SHORT TERM...DRK
LONG TERM....HLO
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
415 PM EST WED FEB 1 2012
LATEST UPDATE...ALL EXCEPT AVIATION...
.SYNOPSIS...(415 PM EST WED FEB 1 2012)
HIGH PRESSURE WILL PROVIDE TRANQUIL WEATHER INTO FRIDAY WITH
GENERALLY PARTLY CLOUDY SKIES. MILD CONDITIONS WILL CONTINUE WITH
HIGH TEMPERATURES FORECAST TO PUSH TO AROUND 40 BOTH THURSDAY AND
FRIDAY. NORMAL HIGHS FOR THIS TIME OF YEAR AROUND NEAR 30 DEGREES.
A SYSTEM MAY APPROACH THE SOUTHERN GREAT LAKES OVER THE WEEKEND AND
BRUSH THE AREA WITH A CHANCE OF LIGHT SNOW AND LIGHT RAIN. AT THIS
POINT IT APPEARS THE BRUNT OF THE SYSTEM IN THE FORM OF RAINFALL
WILL BE SOUTH OF THE AREA.
&&
.SHORT TERM...(415 PM EST WED FEB 1 2012)
(TONIGHT THROUGH FRIDAY NIGHT)
NOT MUCH IN THE WAY OF CONCERNS THROUGH THE SHORT TERM. MAIN ITEM
WILL BE THE EXTENT OF LOW CLOUDS TONIGHT. DECIDED GIVEN CLIMATOLOGY
TO ROLL WITH LOWER CLOUDS TRYING TO HANG ON. USED A MOSTLY CLOUDY
WORDING THROUGH THE NIGHT FOR NOW. BUFKIT RUC OVERVIEWS SHOW
MOISTURE HANGING ON BETWEEN 2000-3500FT INTO THURSDAY MORNING. THERE
MAY BE SOME EBB AND FLOW TO THE CLOUDS THOUGH AS THERE IS A CLEARING
LINE PRESSING IN FROM THE SOUTHWEST. ENVISION SOME CLEARING THIS
EVENING WITH THE CLOUDS FILLING BACK IN OVERNIGHT.
BEYOND TONIGHT...GENERALLY A PARTLY CLOUDY FORECAST WITH SURFACE
HIGH PRESSURE IN PLACE. COMPLICATING FACTORS THOUGH ARE A SHORTWAVE
DIVING SOUTHEAST ON THURSDAY WHICH MAY INCREASE CLOUD COVER AND
POTENTIALLY SOME LOW CLOUDS FILTERING IN BEHIND THE WAVE THURSDAY
NIGHT AND FRIDAY.
&&
.LONG TERM...(415 PM EST WED FEB 1 2012)
(SATURDAY THROUGH WEDNESDAY)
FORECAST CONCERNS CONTINUE TO BE THE LOW MOVING OUT OF THE SRN
PLAINS OVER THE WEEKEND.
THE GFS REMAINS CONSISTENT IN MOVING THE LOW FROM OKLAHOMA EAST
ACROSS THE OHIO VALLEY. THE NAM IS ON BOARD WITH THIS SOLUTION. THE
ECMWF IS NOW GIVING A NOD TO THE GFS BY DEVELOPING A LOW OVER
KENTUCKY AND THEN SHEARING IT OUT INTO A TROUGH OVER THE
APPALACHIANS. WITH THE ECMWF NOW WEAKENING IT/S LOW OVER IOWA AND
DEVELOPING ONE FARTHER SOUTH...CONFIDENCE IS INCREASING THAT A LOW
WILL MOVE ACROSS THE OHIO VALLEY OVER THE WEEKEND. THIS TRACK
COUPLED WITH FORECAST SOUNDINGS ALSO SUGGESTS THAT ALL THE PCPN WILL
BE SNOW. HOW MUCH PCPN WE SEE IS STILL UP IN THE AIR...SO TO SPEAK.
BOTH THE NAM/GFS SHOW A NICE SLUG OF PCPN BEHIND THE LOW LIKELY
ASSOCIATED WITH DEFORMATION PROCESSES. HIGHEST CHANCES FOR PCPN WILL
BE ALONG/SOUTH OF I-96 SATURDAY AND SUNDAY. MONDAY LOOKS DRY BEFORE
ANOTHER SHORT WAVE MOVING SOUTH ACROSS THE GREAT LAKES BOOSTS PCPN
CHANCES TUESDAY/WEDNESDAY. TEMPS WILL BE MOSTLY ABOVE NORMAL THROUGH
THE PERIOD.
&&
.AVIATION...(103 PM EST WED FEB 1 2012)
MVFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD. A LARGE EXPANSE OF
LOW CLOUDS STRETCHES ACROSS THE UPPER MIDWEST. MODEL RH PROGS SHOW
ABUNDANT LOW LEVEL MOISTURE BELOW 4K FT THROUGH TONIGHT. LOOK FOR
CIGS IN THE 1500-2500 RANGE.
&&
.MARINE...(415 PM EST WED FEB 1 2012)
SURFACE RIDGING WILL BE SITUATED OVER THE GREAT LAKES AREA THE NEXT
36 HOURS OF SO...PROVIDING RELATIVELY TRANQUIL CONDITIONS OUT ON THE
LAKE. WAVES AROUND 1 FOOT ARE EXPECTED INTO FRIDAY WITH WINDS OF 10
KNOTS OR LESS.
&&
.HYDROLOGY...(415 PM EST WED FEB 1 2012)
RAIN IN THE LAST WEEK OR SO...COMBINED WITH SNOWMELT THE LAST COUPLE
OF DAYS HAS LED TO ELEVATED RIVER LEVELS ACROSS THE AREA. THAT
SAID...MOST SITES REMAIN...OR ARE FORECAST TO REMAIN WITHIN BANK.
THE USGS PERCENT OF NORMAL PAGE INDICATES THAT MOST SITES ARE IN
EITHER THE ABOVE NORMAL OR MUCH ABOVE NORMAL CATEGORY. THE KALAMAZOO
RIVER BASIN AND THE UPPER REACHES OF THE GRAND ARE THE HIGHEST. WE
CURRENTLY HAVE RIVER FLOOD ADVISORIES OUT FOR BURLINGTON...VICKSBURG
AND IONIA. THESE SITES ARE NOT PROJECT TO REACH WARNING STATUS. WITH
DRY WEATHER FORECAST THE NEXT COUPLE DAYS...RIVER HEADLINES SHOULD
REMAIN FAIRLY STABLE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE
LONG TERM: 93
AVIATION: 93
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
340 PM EST WED FEB 1 2012
.SHORT TERM...THIS EVENING AND TONIGHT
HIGH PRESSURE SYSTEM OVER THE UPPER MISSISSIPPI VALLEY WILL
BUILD OVER THE GREAT LAKES OVERNIGHT WITH THE RIDGE AXIS OVERHEAD BY
AROUND 12Z. WITH THE PRESSURE GRADIENT ALREADY RELAXING...WIND
SPEEDS ALREADY ON THE DECLINE WILL CONTINUE UNTIL THEY ARE LIGHT AND
VARIABLE BY MORNING. THE MAIN FORECAST CONCERN IS WITH CLOUD/FOG
POTENTIAL FOR THE OVERNIGHT. STRATUS DECK AROUND 3KFT MANAGED TO
FILL IN OVER ALL OF SE MI THIS MORNING EXTENDING BACK WEST INTO
IA/MN...UNDER THE NORTH SIDE OF THE RIDGE AXIS THAT WILL BE MOVING
OVERHEAD TONIGHT. EXPECT THIS LOW STRATUS DECK TO THIN OUT SOMEWHAT
THIS EVENING WHILE HIGHER CIRRUS CLOUDS THICKEN TONIGHT. RUC MODEL
SOUNDINGS AGREE WITH THIS THINKING THOUGH IT KEEPS LOW LEVEL
MOISTURE VALUES QUITE HIGH IN THE LOWEST 3KFT. THE NAM DOES ITS
USUAL AND IS EVEN MORE ROBUST WITH BOUNDARY LAYER SO LEANING MORE
TOWARD RUC. SO MODELS SHOW THERE IS POTENTIAL FOR THE STRATUS TO
LINGER LONGER THROUGH THE NIGHT. EVEN THOUGH MANY OF THE ASOS
STATIONS IN IA/MN/WI REPORTED FOG WITH VISIBILITY RESTRICTIONS DOWN
TO 2-4 MILES EARLY THIS MORNING...THE ABUNDANT CLOUD COVER WE WILL
HAVE IN PLACE SHOULD PREVENT MUCH FOG FORMATION IF ANY. RAISED MIN
TEMPS TONIGHT A DEGREE OR 2 TO ACCOUNT FOR THE THICKER CLOUDS.
&&
.LONG TERM...THURSDAY THROUGH NEXT WEDNESDAY
FORECAST CONTINUES TO LOOK FAIRLY QUIET DURING THE EXTENDED
PERIOD...AT LEAST FOR FEBRUARY. TEMPERATURES WILL CONTINUE TO RUN
ABOVE NORMAL INTO THE BEGINNING OF NEXT WEEK BEFORE A STRONG COLD
FRONT DROPS TEMPERATURES BACK CLOSER TO NORMAL NEXT WEDNESDAY.
UPPER SHORTWAVE OVER SOUTHERN MANITOBA THIS AFTERNOON WILL DROP DOWN
ACROSS THE NORTHERN GREAT LAKES THURSDAY. THIS SHOULD KEEP THE
SURFACE RIDGE INTACT OVER SOUTHEAST LOWER MICHIGAN...WHILE A WEAK
SURFACE TROUGH SLIDES ACROSS NORTHERN MICHIGAN IN RESPONSE. THINK
LIGHT SNOW SHOWERS WILL STAY NORTH OF THE AREA AND HAVE KEPT THE
FORECAST DRY...WITH THE MAIN IMPACT FROM THIS SHORTWAVE EXPECTED TO
BE AN INCREASE IN MID LEVEL MOISTURE OVER CENTRAL MICHIGAN. MODEL
FORECAST SOUNDINGS THROUGH THURSDAY NIGHT KEEP A SUBSIDENCE
INVERSION IN PLACE ACROSS SOUTHEAST MICHIGAN...GENERALLY BETWEEN
900-800MB. ALTHOUGH GFS/NAM DO NOT SHOW AN OVERABUNDANCE OF
LOW-LEVEL MOISTURE REMAINING TRAPPED IN THE LOWER LEVELS...DID LEAN
MORE PESSIMISTIC WITH THE SKY COVER FORECAST (MORE CLOUDS) THAN
MODELS SUGGEST GIVEN POOR MIXING AND LIGHT WEST TO NORTHWEST FLOW
OFF LAKE MICHIGAN. ASSUMING THERE IS A LOWER CLOUD DECK...WILL HAVE
TO SEE IF MID-LEVEL MOISTURE OVERRUNNING ANY MOISTURE TRAPPED
UNDERNEATH THE SUBSIDENCE INVERSION COULD SEED LOWER CLOUDS ACROSS
CENTRAL MICHIGAN...WHICH WOULD MAYBE PRODUCE SOME FLURRIES. GIVEN
THE EXPECTATION FOR MORE CLOUDS AND VERY LIGHT WINDS/POOR
MIXING...WENT ON THE COOL SIDE OF MOS GUIDANCE FOR HIGHS
THURSDAY...IN THE MID 30S TO LOW 40S.
THE RIDGE WILL THEN RESTRENGTHEN OVER THE CENTRAL GREAT LAKES
THURSDAY NIGHT AND FRIDAY...BEFORE ANOTHER UPPER SHORTWAVE DROPS
DOWN THROUGH THE CENTRAL GREAT LAKES FRIDAY NIGHT. GFS/NAM BRING A
WEAK FRONT DOWN ACROSS THE AREA WITH THIS FEATURE...BUT IT LOOKS
MOISTURE STARVED AND SHOULD DO LITTLE BUT INCREASE CLOUDS ONCE
AGAIN. NAM IS SLOWER WITH BOTH THE FRONT AND SOUTHWARD PROGRESS WITH
THIS WAVE ACROSS THE GREAT LAKES FRIDAY/FRIDAY NIGHT...AND HAVE
THEREFORE HEAVILY FAVORED THE OTHER MODELS WITH THE ARRIVAL OF
LOW-LEVEL MOISTURE AND PRECIPITATION LATE FRIDAY NIGHT INTO
SATURDAY. WITH THE SLOWER TIMING...NAM ALLOWS AN APPROACHING LOW
PRESSURE SYSTEM AND ASSOCIATED AREA OF DEFORMATION TO MAKE QUICKER
AND FURTHER INROADS INTO THE SOUTHERN GREAT LAKES.
REX BLOCK PATTERN WILL DEVELOP OVER THE WEST COAST BY FRIDAY...PER
STRONG CONSENSUS FROM FORECAST MODELS. THIS BLOCK WILL THEN VERY
SLOWLY MAKES IT WAY EAST INTO THE CENTRAL CONUS AND TOPPLE OVER THE
WEEKEND. MODELS REMAIN VERY DIVIDED ON HOW LONG IT WILL TAKE THE
UPPER LOW ON THE SOUTHERN END OF THE BLOCK TO LIFT UP INTO THE
SOUTHERN GREAT LAKES. SPREAD IS ANYWHERE FROM SATURDAY NIGHT (12Z
GFS) TO EARLY MONDAY (12Z GEM)...AND CONFIDENCE SURROUND TIMING OF
WEATHER IMPACTS FROM THIS FEATURE ARE VERY LOW. UKMET/GEM/EURO KEEP
THE SYSTEM FAR ENOUGH SOUTH OF THE AREA NOW TO SUPPORT A DRY
FORECAST THROUGH AT LEAST SATURDAY NIGHT. DID HOWEVER KEEP A SLIGHT
CHANCE FOR RAIN/SNOW NEAR THE OHIO BORDER SATURDAY AFTERNOON AND
OVERNIGHT...WITH LOW CHANCES FOR LIGHT SNOW SHOWERS BY SUNDAY NIGHT.
UPPER TROUGHING LOOKS TO BUILD OVER THE NORTHEASTERN PORTION OF
NORTH AMERICA AND THE GREAT LAKES TOWARDS THE MIDDLE OF THE
WEEK...WITH SEVERAL SHORTWAVE TROUGHS DROPPING DOWN ACROSS THE AREA
MONDAY THROUGH WEDNESDAY. GFS/EURO ALSO AGREE WITH A FAIRLY STRONG
COLD FRONT DROPPING DOWN THROUGH MICHIGAN ON TUESDAY (THOUGH THERE
REMAIN SLIGHT TIMING DIFFERENCES). THIS WOULD BRING A QUICK SHOT OF
SNOW SHOWERS AND DROP TEMPERATURES BACK DOWN TO NEAR NORMAL BY
WEDNESDAY.
&&
.MARINE...
HIGH PRESSURE OVER THE WESTERN GREAT LAKES WILL BUILD EASTWARD
OVERNIGHT WITH THE RIDGE AXIS ACROSS LAKE HURON BY THURSDAY MORNING.
THE PRESSURE GRADIENT HAS ALREADY WEAKENED SUBSTANTIALLY THROUGH THE
DAY ALLOWING WINDS TO DECREASE WITH MAX GUSTS REACHING 20 KNOTS OVER
THE OPEN WATERS OF LAKE HURON. WINDS AND WAVE WILL CONTINUE TO
DECREASE THROUGH THE NIGHT AS THE RIDGE AXIS DRAWS NEARER. THIS HIGH
PRESSURE SYSTEM WILL PRODUCE VERY FAVORABLE MARINE CONDITIONS INTO
THE WEEKEND. A LOW PRESSURE TROUGH WILL PASS THROUGH THE REGION ON
THURSDAY...THOUGH IT WILL BE VERY WEAK AND WILL MOST LIKELY NOT BE
ABLE TO PUT A DENT IN THE LARGER SCALE RIDGE IN PLACE.
&&
.AVIATION...ISSUED 1241 PM EST WED FEB 1 2012
//DISCUSSION...
MAIN CONCERN FOR THIS ISSUANCE IS THE STRATUS DECK THAT FILLED IN
OVER SOUTHEAST MICHIGAN THIS MORNING. SHORT TERM MODELS STILL
DISAGREE AS TO WHETHER DAYTIME HEATING WILL SCATTER OUT THE STRATUS
OR NOT THIS AFTERNOON. JUDGING FROM 12Z SOUNDINGS FROM DTX/APX IT
APPEARS THAT THE INVERSION IS STRONGER THEN FORECAST WHICH WILL KEEP
THE STRATUS FROM MIXING OUT. THUS HAVE GONE MORE PESSIMISTIC HOLDING
MVFR CIGS INTO THIS EVENING. HIGH PRESSURE AND CIRRUS MOVING IN FROM
THE WEST ADD A LEVEL OF COMPLEXITY TO THE FORECAST AS TO POTENTIAL
VISIBILITY RESTRICTIONS FOR FOG OVERNIGHT. UPSTREAM OBSERVATIONS
SHOWED MANY LOCATIONS WITH MVFR/IFR VSBYS LAST NIGHT...BUT AS
MENTIONED THE CIRRUS AND HIGH PRESSURE WILL WORK AGAINST THAT. AT
THIS POINT JUST LEFT A MENTION OF LOW SCATTERED CLOUDS AS CONFIDENCE
IS LOW THAT FOG WILL FORM.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE THAT CEILING WILL REMAIN BELOW 5000 FEET INTO
THIS EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...DRK
LONG TERM....HLO
MARINE.......DRK
AVIATION.....DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
103 PM EST WED FEB 1 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(410 AM EST WED FEB 1 2012)
TEMPERATURES WILL CONTINUE TO AVERAGE ABOVE NORMAL THROUGH THE
WEEKEND INTO EARLY NEXT WEEK. TRANQUIL WEATHER IS ANTICIPATED
THROUGH AT LEAST FRIDAY. LOW PRESSURE TRACKING EAST FROM THE PLAINS
MAY BRING SOME PRECIPITATION BY SATURDAY.
&&
.SHORT TERM...(1134 AM EST WED FEB 1 2012)
(THIS AFTERNOON THROUGH FRIDAY AFTERNOON)
UPDATED TO GO MOSTLY CLOUDY THROUGH THE AFTERNOON. RUC AND GFS LOW
LEVEL MOISTURE PROGS INDICATE QUITE A BIT OF MOISTURE HANGING ON.
THERE ARE A FEW BREAKS IN THE OVERCAST DEVELOPING IN WISCONSIN AND
ILLINOIS...BUT THE AFTERNOON WILL AT LEAST START OFF MOSTLY CLOUDY.
THINKING WAS RIDGING BUILDING IN WOULD KNOCK OUT SOME OF THE
MOISTURE...BUT IT APPEARS THE TRAPPING INVERSION MAY BE TOO STRONG.
BOTH THE DETROIT AND GREEN BAY MORNING SOUNDINGS INDICATE A FAIRLY
STRONG INVERSION. OTHER THAN THE PESKY LOW CLOUDS...CONDITIONS ARE
RATHER QUIET THIS AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS...
A SHORTWAVE MOVING THROUGH LATE TONIGHT INTO THURSDAY MORNING MAY
BRING A LITTLE MORE CLOUD COVER BUT NO PCPN.
A SFC RIDGE IN CONJUNCTION WITH AN UPPER RIDGE BUILDING IN FROM THE
WEST THURSDAY THROUGH THURSDAY NIGHT WILL BRING FAIR AND SEASONABLY
MILD WX THURSDAY THROUGH THURSDAY NIGHT INTO FRIDAY. MAX TEMPS
THURSDAY AND FRIDAY WILL REACH THE LOWER 40S ACROSS MOST OF OUR FCST
AREA.
&&
.LONG TERM...(410 AM EST WED FEB 1 2012)
(FRIDAY NIGHT THROUGH TUESDAY)
MODELS ARE IN GOOD AGREEMENT ON THE POSITION OF THE CENTRAL PLAINS
UPPER LOW THROUGH 12Z SATURDAY BUT THEN DIVERGE SIGNIFICANTLY AFTER
THAT. AS SUCH... THIS IS A LOW CONFIDENCE LONG TERM FORECAST IN
TERMS OF PCPN POTENTIAL OVER THE WEEKEND.
THE GENERAL IDEA/THEME SEEMS TO BE THAT PCPN RELATED TO THE CENTRAL
PLAINS SYSTEM WILL HAVE A DIFFICULT TIME MAKING MUCH HEADWAY INTO
SRN LWR MI OVER THE WEEKEND. THIS IS DUE TO A RESISTANT CONFLUENT
MID/UPR FLOW OVERHEAD (RELATED TO THE UPR TROUGH IN ERN CANADA) AND
A DRY AIR MASS IN PLACE. NO BIG CHANGES THEREFORE ARE NEEDED ATTM TO
THE WEEKEND FCST... WHICH INCLUDES ONLY LOW CHANCE POPS FOR SNOW OR
MIXED PCPN.
FOR EARLY NEXT WEEK...GUIDANCE SUGGESTS THAT WHATEVER REMAINS OF THE
AFOREMENTIONED UPPER LOW/TROUGH WILL EVENTUALLY GET ABSORBED/PHASED
IN WITH A NRN STREAM TROUGH COMING DOWN FROM THE NORTHWEST. HAVE
THEREFORE KEPT SOME LOW CHANCE POPS GOING FOR MONDAY AND TUESDAY OF
NEXT WEEK.
WHILE THE PCPN ASPECT OF THE LONG TERM FCST IS LOW CONFIDENCE...
THERE IS HIGH CONFIDENCE THAT TEMPERATURES WILL CONTINUE TO AVERAGE
ABOVE NORMAL THROUGH EARLY NEXT WEEK.
&&
.AVIATION...(103 PM EST WED FEB 1 2012)
MVFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD. A LARGE EXPANCE OF
LOW CLOUDS STRECHES ACROSS THE UPPER MIDWEST. MODEL RH PROGS SHOW
ABUNDANT LOW LEVEL MOISTURE BELOW 4K FT THROUGH TONIGHT. LOOK FOR
CIGS IN THE 1500-2500 RANGE.
&&
.MARINE...(410 AM EST WED FEB 1 2012)
THE SCA REMAINS IN EFFECT UNTIL 7 AM THIS MORNING. WAVE HEIGHTS WILL
SUBSIDE TO 2 TO 4 FEET LATER THIS MORNING AND TO 1 TO 3 FEET BY THIS
AFTERNOON AS HIGH PRESSURE BUILDS IN AND NORTHWEST WINDS DIMINISH.
&&
.HYDROLOGY...(410 AM EST WED FEB 1 2012)
NO SIGNIFICANT HYDRO ISSUES ANTICIPATED THIS WEEK WITH SEASONABLY
MILD AND DRY CONDITIONS THROUGH FRIDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY IN EFFECT THROUGH 7 AM TODAY FOR THE
ENTIRE NEARSHORE.
&&
$$
SYNOPSIS: LAURENS
SHORT TERM: LAURENS/DUKE
LONG TERM: MEADE
AVIATION: 93
MARINE: LAURENS
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1134 AM EST WED FEB 1 2012
LATEST UPDATE...SHORT TERM...
.SYNOPSIS...(410 AM EST WED FEB 1 2012)
TEMPERATURES WILL CONTINUE TO AVERAGE ABOVE NORMAL THROUGH THE
WEEKEND INTO EARLY NEXT WEEK. TRANQUIL WEATHER IS ANTICIPATED
THROUGH AT LEAST FRIDAY. LOW PRESSURE TRACKING EAST FROM THE PLAINS
MAY BRING SOME PRECIPITATION BY SATURDAY.
&&
.SHORT TERM...(1134 AM EST WED FEB 1 2012)
(THIS AFTERNOON THROUGH FRIDAY AFTERNOON)
UPDATED TO GO MOSTLY CLOUDY THROUGH THE AFTERNOON. RUC AND GFS LOW
LEVEL MOISTURE PROGS INDICATE QUITE A BIT OF MOISTURE HANGING ON.
THERE ARE A FEW BREAKS IN THE OVERCAST DEVELOPING IN WISCONSIN AND
ILLINOIS...BUT THE AFTERNOON WILL AT LEAST START OFF MOSTLY CLOUDY.
THINKING WAS RIDGING BUILDING IN WOULD KNOCK OUT SOME OF THE
MOISTURE...BUT IT APPEARS THE TRAPPING INVERSION MAY BE TOO STRONG.
BOTH THE DETROIT AND GREEN BAY MORNING SOUNDINGS INDICATE A FAIRLY
STRONG INVERSION. OTHER THAN THE PESKY LOW CLOUDS...CONDITIONS ARE
RATHER QUIET THIS AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS...
A SHORTWAVE MOVING THROUGH LATE TONIGHT INTO THURSDAY MORNING MAY
BRING A LITTLE MORE CLOUD COVER BUT NO PCPN.
A SFC RIDGE IN CONJUNCTION WITH AN UPPER RIDGE BUILDING IN FROM THE
WEST THURSDAY THROUGH THURSDAY NIGHT WILL BRING FAIR AND SEASONABLY
MILD WX THURSDAY THROUGH THURSDAY NIGHT INTO FRIDAY. MAX TEMPS
THURSDAY AND FRIDAY WILL REACH THE LOWER 40S ACROSS MOST OF OUR FCST
AREA.
&&
.LONG TERM...(410 AM EST WED FEB 1 2012)
(FRIDAY NIGHT THROUGH TUESDAY)
MODELS ARE IN GOOD AGREEMENT ON THE POSITION OF THE CENTRAL PLAINS
UPPER LOW THROUGH 12Z SATURDAY BUT THEN DIVERGE SIGNIFICANTLY AFTER
THAT. AS SUCH... THIS IS A LOW CONFIDENCE LONG TERM FORECAST IN
TERMS OF PCPN POTENTIAL OVER THE WEEKEND.
THE GENERAL IDEA/THEME SEEMS TO BE THAT PCPN RELATED TO THE CENTRAL
PLAINS SYSTEM WILL HAVE A DIFFICULT TIME MAKING MUCH HEADWAY INTO
SRN LWR MI OVER THE WEEKEND. THIS IS DUE TO A RESISTANT CONFLUENT
MID/UPR FLOW OVERHEAD (RELATED TO THE UPR TROUGH IN ERN CANADA) AND
A DRY AIR MASS IN PLACE. NO BIG CHANGES THEREFORE ARE NEEDED ATTM TO
THE WEEKEND FCST... WHICH INCLUDES ONLY LOW CHANCE POPS FOR SNOW OR
MIXED PCPN.
FOR EARLY NEXT WEEK...GUIDANCE SUGGESTS THAT WHATEVER REMAINS OF THE
AFOREMENTIONED UPPER LOW/TROUGH WILL EVENTUALLY GET ABSORBED/PHASED
IN WITH A NRN STREAM TROUGH COMING DOWN FROM THE NORTHWEST. HAVE
THEREFORE KEPT SOME LOW CHANCE POPS GOING FOR MONDAY AND TUESDAY OF
NEXT WEEK.
WHILE THE PCPN ASPECT OF THE LONG TERM FCST IS LOW CONFIDENCE...
THERE IS HIGH CONFIDENCE THAT TEMPERATURES WILL CONTINUE TO AVERAGE
ABOVE NORMAL THROUGH EARLY NEXT WEEK.
&&
.AVIATION...(645 AM EST WED FEB 1 2012)
MVFR CIGS OF 1500-2500 FEET WERE SPREADING INTO SRN LWR MI EARLY
THIS MORNING FROM THE NORTH AND WEST. HOWEVER LOW LEVEL RH PROGS
SUGGEST THESE CLOUDS SHOULD SCOUR OUT BY 18Z DUE TO STRONG
SUBSIDENCE... SO WENT VFR FOR THIS AFTERNOON AND TONIGHT.
&&
.MARINE...(410 AM EST WED FEB 1 2012)
THE SCA REMAINS IN EFFECT UNTIL 7 AM THIS MORNING. WAVE HEIGHTS WILL
SUBSIDE TO 2 TO 4 FEET LATER THIS MORNING AND TO 1 TO 3 FEET BY THIS
AFTERNOON AS HIGH PRESSURE BUILDS IN AND NORTHWEST WINDS DIMINISH.
&&
.HYDROLOGY...(410 AM EST WED FEB 1 2012)
NO SIGNIFICANT HYDRO ISSUES ANTICIPATED THIS WEEK WITH SEASONABLY
MILD AND DRY CONDITIONS THROUGH FRIDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY IN EFFECT THROUGH 7 AM TODAY FOR THE
ENTIRE NEARSHORE.
&&
$$
SYNOPSIS: LAURENS
SHORT TERM: LAURENS/DUKE
LONG TERM: MEADE
AVIATION: MEADE
MARINE: LAURENS
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1207 PM EST WED FEB 1 2012
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL MOVE EAST OF THE REGION THIS
MORNING. HIGH PRESSURE OVER THE WESTERN GREAT LAKES LATER TODAY
WILL MOVE OVER THE LOCAL AREA BY EARLY FRIDAY. THIS HIGH WILL
SHIFT TO THE EAST COAST BY THE START OF THE WEEKEND BUT MAINTAIN A
RIDGE ACROSS THE UPPER OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ADJUSTED CLOUDS FOR REST OF AFTERNOON TO ALLOW TO MORE CU AND
STRATOCU. ALSO ADJUSTED TEMPS FOR AFTERNOON DOWN WHERE MORE CLOUDS
EXPECTED AND UP IN THE SOUTH AND SE WHERE AFTERNOON SHOULD REMAIN
PARTLY CLOUDY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE REMAINDER OF THE
WEEK. AN UPPER WAVE WILL DIVE SE ACROSS THE CENTRAL LAKES ON
THURSDAY. THIS FEATURE WILL BRING SOME MID AND HIGH LEVEL
CLOUDINESS TO THE AREA BUT LOW LEVELS WILL REMAIN TOO DRY FOR ANY
PRECIP CONCERNS. THE HIGH WILL REESTABLISH ITSELF ON FRIDAY AND
FRIDAY NIGHT. THIS WILL RESULT IN MORE PARTLY CLOUDY TO MOSTLY
CLEAR SKIES. MODELS BEGIN TO DIVERGE ON SATURDAY WITH THE LOW
PRESSURE SYSTEM HEADING NE OUT OF THE SOUTHERN PLAINS. THE LATEST
GFS AND NAM BRING PRECIP INTO THE WESTERN END OF THE AREA AS EARLY
AS SATURDAY MORNING. THE LATEST ECMWF MAINTAINS A DRY EASTERLY
FLOW OVER THE REGION A WHILE LONGER AND THUS IS SLOWER WITH THE
PRECIP. WILL TREND TOWARD THIS DRIER AND SLOWER SOLUTION. HAVE
BACKED OFF ON PRECIP CHANCES FOR SATURDAY AND WILL KEEP IT ONLY IN
THE WEST SATURDAY NIGHT. THINK BETTER CHANCES WILL COME AFTER THE
SHORT TERM PERIOD ENDS. TEMPS WILL REMAIN MILD DURING THE PERIOD
AND HAVE USED A BLEND OF GUIDANCE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
STILL HAVE LOW CONFIDENCE IN THE LONG TERM FORECAST AND HAVE MADE
FEW CHANGES. ECMWF LINGERS THE CUTOFF LOW ACROSS THE MID SECTION OF
THE COUNTRY LONGER THAN THE GFS AND THIS SLOWER SOLUTION IS LIKELY
THE BETTER WAY TO GO. THE OTHER PROBLEM LIES WITH THE NORTHERN
STREAM AND THE TIMING OF A TROUGH TO COME DOWN ACROSS THE EASTERN
GREAT LAKES. HPC CONTINUES TO FAVOR THE ECENS FOR ITS SOMEWHAT
BETTER BIG PICTURE CONSISTENCY AND HAVE WEIGHTED THE FORECAST TO THE
OP ECMWF AND HPC/ECENS. THIS IS THE ROUTE WE HAVE BEEN TAKING AND
THEREFORE LITTLE HAS CHANGED TO THE FORECAST.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1130Z COLD FRONT WAS LOCATED FROM NEAR SANDUSKY TO FINDLAY.
SHOWERS WERE WELL AHEAD OF IT AND WERE ALREADY EXITING EASTERN
TAF SITES. CLEARING MOVING IN QUICKLY SO FIRST QUESTION WILL BE
HOW MUCH PROGRESS WILL IT MAKE. BOTH THE NAM AND THE HRRR GUIDANCE
CLEAR OUT THE LOW CLOUDS QUICKLY THIS MORNING AND HAVE FOLLOWED
THAT BECAUSE WHAT IS ALREADY OCCURRING UPSTREAM. ANOTHER AREA OF
MVFR CEILINGS WERE OVER THE CHICAGO AREA...BUT DO NOT THINK THESE
HAVE MUCH OF ANY CHANCE OF HOLDING TOGETHER TO REACH TOL. SOME
CIRRUS OVERHEAD LATER THIS AFTERNOON. WINDS AFTER THE FRONTAL
PASSAGE WILL BE FROM THE WEST AND WILL LOSE THE GUSTINESS.
DIFFERENCES EXIST ON AVIATION WEATHER FOR TONIGHT INTO THURSDAY.
THERE IS A SOUTHERN SYSTEM TO MOVE ACROSS KY AND THEN THERE WILL
BE A GENERAL TROUGH ALOFT PASSING. GFS LAMP DATA KEPT TODAY CLOUDY
WITH NON VFR CEILINGS AND KEPT THIS OVERNIGHT TOO...AND ACTUALLY
LOWERING TO IFR IN SOME PLACES. NAM GUID NOT SO PESSIMISTIC. WILL
TAKE MIDDLE ROAD FOR NOW AND JUST PUT IN SOME 3500 FT CEILINGS.
.OUTLOOK...NON-VFR CONDITIONS ARE POSSIBLE THURSDAY...LINGERING
ACROSS NE OH/NW PA INTO FRIDAY. NON VFR POSSIBLE AGAIN SUNDAY.
&&
.MARINE...
COLD FRONT TO CROSS THE LAKE THIS MORNING AND SHIFT WINDS TO THE
WEST. WINDS WILL DIMINISH BEHIND THE FRONT. SMALL CRAFT ADVISORY
WILL CONTINUE FOR TODAY FOR THE EAST HALF. HIGH PRESSURE CENTERED TO
THE NORTH OF THE LAKE WILL LARGELY DOMINATE FROM LATER TODAY THROUGH
FRIDAY. FOR THE WEEKEND AND EARLY NEXT WEEK...ONE SYSTEM WILL TRACK
EAST ACROSS THE OHIO VALLEY AND A TROUGH WILL AFFECT THE EASTERN
LAKES...ALTHOUGH FORECAST CONFIDENCE STILL REMAINS LOW FOR NEXT
WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...ADAMS/KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...BC
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
311 PM CST WED FEB 1 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
311 PM CST WED FEB 1 2012
MAIN FORECAST CONCERNS ARE CLOUDS AND FOG TRENDS THIS
EVENING/TONIGHT...THEN PRECIPITATION CHANCES AND TYPES FRIDAY NIGHT
INTO SATURDAY.
LATEST VISIBLE SATELLITE IMAGERY SHOWING LOW STRATUS/DENSE FOG
BEGINNING TO DIMINISH ACROSS THE UPPER GREAT LAKES REGION. LATEST
20Z METARS ARE INDICATING VISIBILITIES IMPROVING OVER PORTIONS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
THE 01.12Z DETERMINISTIC GFS/NAM ARE IN DECENT AGREEMENT WITH
OVERALL UPPER LEVEL AND SURFACE FEATURES THROUGH 00Z SATURDAY.
THEN...BEGIN TO DIVERGE SLIGHTLY ON TIMING AND PLACEMENT OF UPPER
LEVEL/SURFACE LOW INTO THE GREAT LAKES REGION AFTER 00Z SATURDAY.
ANOTHER SIGNIFICANT DIFFERENCE OCCURS AFTER 00Z SATURDAY...AS THE
01.12Z NAM IS COOLER ON NORTHERN PERIPHERY OF UPPER
LEVEL/SURFACE LOW PER BUFKIT SOUNDINGS THAN THE GFS. THIS WILL HAVE
IMPACTS ON PRECIPITATION TYPE FRIDAY NIGHT AND INTO SATURDAY.
TONIGHT...WITH LOW STRATUS AND DENSE FOG DIMINISHING ACROSS
FORECAST AREA...WILL CANCEL DENSE FOG ADVISORY ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THE LATEST 01.12Z GFS/NAM
AND 01.15Z RUC INDICATE INVERSION TO SET UP OVER THE FORECAST AREA
THIS EVENING. WITH ABUNDANT BOUNDARY LAYER MOISTURE...DUE TO CLOUD
COVER DURING THE DAY. HAVE INTRODUCED AREAS OF FOG TONIGHT INTO
THURSDAY MORNING ACROSS FORECAST AREA.
ALL THE 01.12Z DETERMINISTIC MODELS ARE CARVING TROUGH AND CUTTING
OFF UPPER LEVEL LOW OVER THE WESTERN UNITED STATES THURSDAY NIGHT
INTO FRIDAY...THEN SLOWLY LIFT UPPER LEVEL LOW INTO THE UPPER
MIDWEST AND GREAT LAKES REGION FRIDAY NIGHT INTO SATURDAY. THE
MODELS DO INDICATE DECENT ISENTROPIC LIFT AT 290K SURFACE AND DEEP QG
FORCING OVER PORTIONS OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
THIS WILL SPREAD A BAND OF PRECIPITATION INTO THIS AREA AFTER 06Z
SATURDAY. THE LATEST 01.12Z DETERMINISTIC GFS/NAM DO INDICATE
TEMPERATURES BELOW OR NEAR FREEZING THROUGH THE ATMOSPHERE
COLUMN FRIDAY NIGHT INTO SATURDAY PER BUFKIT SOUNDINGS. HOWEVER...THE
LATEST 01.12Z ECMWF IS MUCH FARTHER WEST WITH THE 850MB LOW AND
ADVECTS SLIGHTLY WARMER AIR NORTHWARD INTO THE REGION. UNCERTAINTIES
EXIST AS TOO HOW MUCH WARM AIR ADVECTS NORTHWARD INTO THE REGION
FRIDAY NIGHT INTO SATURDAY. FOR NOW...HAVE KEPT MAINLY ALL SNOW FROM
06Z THROUGH 18Z SATURDAY...AND A RAIN/SNOW MIX AFTER 18Z SATURDAY
ACROSS MUCH OF THE SOUTHERN HALF OF FORECAST AREA. SIGNIFICANT
SNOW ACCUMULATION WILL DEPEND ON THE EXACT TRACK OF THE UPPER
LEVEL/SURFACE LOW AND THE TEMPERATURES THROUGH THE ATMOSPHERE COLUMN
FRIDAY NIGHT INTO SATURDAY.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
311 PM CST WED FEB 1 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES SATURDAY NIGHT
INTO SUNDAY. THE 01.12Z GFS/ECMWF/GEM CONTINUE TO BE
DIFFERENT IN TIMING AND PLACEMENT OF UPPER LEVEL LOW SLOWLY LIFTING
NORTHEASTWARD INTO THE UPPER GREAT LAKES AND UPPER MIDWEST
SATURDAY NIGHT INTO SUNDAY NIGHT. THE MODELS DO SUGGEST THE
PRECIPITATION IN ASSOCIATION WITH THE UPPER LEVEL LOW WILL BE
CONFINED MAINLY OVER THE SOUTHERN HALF OF THE FORECAST AREA SATURDAY
NIGHT INTO SUNDAY. AS FAR AS PRECIPITATION TYPES...THE 01.12Z GFS
BUFKIT SOUNDINGS DO INDICATE SNOW MAINLY AT NIGHT AND A MIXTURE OF
RAIN AND SNOW DURING THE DAY. AFTER 12Z MONDAY...THE DETERMINISTIC
GEM/GFS/ECMWF ARE IN MUCH BETTER AGREEMENT WITH BUILDING SURFACE
RIDGE INTO THE NORTHERN PLAINS AND THE UPPER MIDWEST. DRY WEATHER
CONDITIONS AND SEASONABLE TEMPERATURES CAN BE EXPECTED ACROSS THE
FORECAST AREA TUESDAY INTO MIDDLE OF NEXT WEEK.
&&
.AVIATION...THROUGH 18Z THURSDAY
1204 PM CST WED FEB 1 2012
WITH THE GFS AND RUC MODEL SOUNDINGS CONTINUING TO SUGGEST THAT
THE LOW LEVEL INVERSION WILL REMAIN IN PLACE THROUGH 02.03Z.
EXTENDED THE DENSE FOG AT KRST THROUGH THIS TIME PERIOD...AND THEN
WENT WITH A GRADUAL IMPROVEMENT IN BOTH VISIBILITIES AND CEILINGS.
MEANWHILE AT KLSE...STILL NOT QUITE SURE WHETHER THE DENSE FOG
WILL MOVE INTO THIS AREA. THE MODELS SUGGEST THAT THIS MAY MOVE
MORE NORTHEAST AND BE FOUND MAINLY ALONG AND NORTH OF THE
INTERSTATE 94 CORRIDOR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
311 PM CST WED FEB 1 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION.....BOYNE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
228 PM CST WED FEB 1 2012
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
OVER SOUTHERN QUEBEC AND A LARGE HIGH PRESSURE SYSTEM STRETCHING
FROM THE SOUTHERN PLAINS INTO THE WESTERN GREAT LAKES. WIDESPREAD
1-2KFT STRATUS EXISTS ACROSS MUCH OF THE WESTERN AND CENTRAL GREAT
LAKES EARLY THIS AFTERNOON...THOUGH EVEN LOWER CEILINGS AND FOG
EXIST BACK TO THE NORTHERN MISSISSIPPI VALLEY. MEANWHILE FARTHER
UPSTREAM...A WEAK SHORTWAVE TROUGH IS DIVING SE OVER THE ND/MANITOBA
BORDER. NOT MUCH PRECIP ACTIVITY WITH THIS WAVE...BUT AS IT TRACKS
TOWARDS NORTHERN WISCONSIN TONIGHT...LIGHT SNOW CHANCES AS WELL AS
CLOUD COVER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...BROAD HIGH PRESSURE OVER THE PLAINS WILL DRIFT
EAST OVER THE WESTERN GREAT LAKES TONIGHT...WHILE A WEAK SHEARED
SHORTWAVE TROUGH DIVES SOUTH OVER NORTHERN WISCONSIN. FORCING IS
PRETTY WEAK WITH THIS WAVE AND MID-LEVELS STRUGGLE TO SATURATE.
STILL THOUGH...DEWPOINT DEPRESSIONS ARE LOW ENOUGH TO WARRANT AT
LEAST FLURRIES OVER NORTHERN WISCONSIN AFTER MIDNIGHT...AND WILL
KEEP A TENTH OR TWO OF ACCUMS ALONG THE U.P. BORDER.
OTHERWISE...THE LIGHT WIND REGIME AND AMPLE MOISTURE STUCK BENEATH
THE BL INVERSION ARE SUPPORTIVE OF THE LOW STRATUS STICKING AROUND
ALL NIGHT LONG. IF HOLES IN THE CLOUDS OCCUR...THEN FOG WOULD
DEVELOP. SO WENT PESSIMISTIC WITH CLOUD COVER FOR THIS FORECAST.
LOWS WILL ONLY FALL A FEW DEGREES WITH THE CLOUD COVER.
THURSDAY...THE SHORTWAVE TROUGH WILL EXIT NE WISCONSIN DURING THE
MORNING AND WILL LEAVE A CHANCE OF FLURRIES IN THE FORECAST.
OTHERWISE...PACIFIC HIGH PRESSURE WILL STICK AROUND THE REGION.
925MB TEMPS DO WARM A FEW DEGREES OVER CENTRAL AND EAST-CENTRAL
WISCONSIN IN THE AFTERNOON. SO WILL SHOW WIDESPREAD LOW STRATUS IN
THE MORNING ERODING THERE FIRST TOMORROW AFTERNOON. TEMPS REMAIN
DIFFICULT PENDING POTENTIAL SUNSHINE AND WILL GO UPPER 30S NORTH TO
MIDDLE 40S SOUTH.
.LONG TERM...THU NGT THRU NXT WED. SPLIT FLOW REMAINS THE RULE
ACROSS THE CONUS DURING THE EXTENDED PART OF THE FCST. ONLY REAL
PBLM TO BE THE EVENTUAL MOVEMENT OF A MODEST CLOSED UPR LOW DURING
THE SUNDAY/MON TIME PERIOD. MDLS HAVE DRIFTED THIS SYSTEM FARTHER
NORTH (ESP THE ECMWF/UKMET) WHICH WOULD NOW BRING A CHC OF PCPN TO
PARTS OF THE FCST AREA. ONCE THIS SYSTEM DEPARTS..A BRIEF SHOT OF
COOLER AIR OVERSPREADS THE GREAT LKS...BUT ONLY APRS TO BE A BLIP
ON THIS WARM WINTER AS TEMPS LOOK TO WARM AGAIN LATER NXT WEEK.
HI PRES TO STRETCH FROM SRN SASKATCHEWAN EWD INTO WRN ONTARIO...
COUPLED WITH ANOTHER HI PRES OVER WRN PA...WL KEEP THE TRANQUIL
WEATHER GOING THU NGT. THERE IS A WEAK THERMAL TROF AT THE SFC
OVER NRN SECTIONS OF THE GREAT LKS WHICH WOULD KEEP MORE CLOUDS
OVER NRN WI THAN CNTRL/E-CNTRL WI. HOWEVER...TIME SECTIONS/FCST
SNDNGS INDICATE THAT MSTR JUST ABV THE SFC MAY BE TRAPPED BLO AN
INVERSION...THUS MOSTLY CLOUDY SKIES EXPECTED THROUGHOUT ALL OF NE
WI. MIN TEMPS WL BE HELD UP BY THESE CLOUDS AND FAVOR THE WARMER
SIDE OF GUIDANCE.
ATTENTION TURNS TOWARD THE CNTRL CONUS AS A CLOSED UPR LOW EXITS
THE ROCKIES AND MOVES INTO THE CNTRL PLAINS ON FRI. INCREASING
SOUTHERLY WINDS ARE EXPECTED TO BEGIN DRAWING GULF MSTR NWD THRU
THE OZARKS INTO THE MID-MS VALLEY WITH SHWRS/TSTMS BREAKING OUT.
MEANWHILE...HI PRES TO EXTEND FROM THE NRN PLAINS EAST THRU NRN
SECTIONS OF THE GREAT LKS AND PROVIDE A DRY EASTERLY FLOW INTO WI.
MAY STILL BE DEALING WITH LINGERING LOW CLOUDS WHICH WOULD PUT A
CRIMP ON MAX TEMPS. FOR NOW...HAVE TEMPERED READINGS DOWN A DEGREE
OR TWO FROM THE PREV FCST...BUT STILL WELL-ABOVE NORMAL.
AS THE UPR LOW SLOWLY TRUDGES ACROSS THE CNTRL PLAINS FRI NGT...
GULF MSTR WL MAKE A SURGE NORTH TOWARD THE GREAT LKS THANKS TO A
50 KT SW LOW-LVL JET. THE AREA OF HI PRES REMAINS ANCHORED OVER
NRN SECTIONS OF THE GREAT LKS...THUS SETTING UP A BATTLE BETWEEN
THE ENTRENCHED DRY AIR AND INCOMING MSTR. HAVE KEPT NRN WI PARTLY
CLOUDY WITH PARTLY TO MOSTLY CLOUDY SKIES FOR CNTRL/E-CNTRL WI.
THIS SET-UP WOULD PROVIDE FOR A WIDE RANGE IN TEMPS WITH THE NORTH
FALLING INTO THE LOWER TO MIDDLE TEENS...WHILE THE LAKESHORE AREAS
ONLY DIP INTO THE MIDDLE TO UPPER 20S. THE CLOSED UPR LOW IS FCST
TO MOVE E-NE INTO THE MIDWEST (VCNTY SRN IA) ON SAT. SOUTHERLY
WINDS OVERRUNNING A WRMFNT STRETCHED FROM THE MIDWEST E-SE INTO
THE OHIO RIVER VALLEY...WL BEGIN TO SPREAD CLOUDS NWD INTO WI BY
SAT AFTERNOON. STILL EXPECT A NICE DAY ACROSS NE WI WITH MAX TEMPS
A GOOD 10 TO 15 DEGS ABV NORMAL.
MDL INCONSISTENTCY PERSISTS WITH THE HANDLING OF THE SYSTEM HEADED
INTO SUNDAY AND THIS RESULTS IN POTENTIALLY SIGNIFICANT SENSIBLE
WEATHER DIFFERENCES FOR THE FCST AREA. IF THIS SYSTEM TRACKS NE...
IT WOULD BRING A LGT SNOW OR SNOW/RAIN THREAT TO MUCH OF NE WI. AN
EWD TRACK WOULD ONLY BRUSH CNTRL/E-CNTRL WI WITH PERHAPS A DUSTING
TO A COUPLE TENTHS OF AN INCH OF SNOW. PREFER TO TAKE A CAUTIOUS
APPROACH HERE UNTIL THE MDLS SETTLE DOWN AND WL ONLY MENTION A SML
POP GENERALLY ALONG/SOUTH OF A MFI-SUE LINE. SML POPS WOULD THEN
BE NEEDED INTO SUNDAY NGT AS THE SYSTEM EITHER MOVES INTO NRN OR
SRN SECTIONS OF THE GREAT LKS RGN. SOME EVIDENCE OF IMPROVING
CONDITIONS FOR MON AS THE SYSTEM PULLS AWAY WITH A WEAK UPR RDG
SLIDING INTO WI. MAX TEMPS TO REMAIN WELL ABV NORMAL WITH PLENTY
OF MIDDLE TO UPPER 30S EXPECTED.
A SECONDARY CDFNT DROPS SWD THRU WI MON NGT...BUT MDLS VARY AS TO
THE EXTENT OF THE COLD AIR TO FILTER INTO THE RGN. THE 12Z ECMWF
HAS BACKED OFF QUITE A BIT WITH 8H TEMPS FALLING INTO THE LOWER TO
MIDDLE TEENS BLO ZERO (COMPARED TO -20C ON ITS PREV RUN). THE GFS
IS COMPARABLE WITH ITS PREV RUN WITH 8H TEMPS AROUND -10C. BASED
ON THE SPLIT FLOW PATN...WL LEAN TOWARD THE GFS SOLN WHICH KEEPS
TEMPS ABV NORMAL THRU TUE. WL NEED TO WATCH FOR POTENTIAL OF LK
EFFECT SNOW SHOWERS FOR VILAS CNTY MON NGT INTO TUE AS TRAJS BECOME
FAVORABLE. HAVE ADDED A SML CHC POP THERE FOR NOW. OTHERWISE...HI
PRES TO START BUILDING EWD FROM THE NRN PLAINS AND KEEP THE REST
OF NE WI ON THE QUIET SIDE. THIS BROAD/STRONG AREA OF HI PRES
SETTLES SOUTH AND EAST ACROSS THE CNTRL CONUS BY NXT WED AND WL
CONT TO PROVIDE DRY CONDITIONS TO NE WI. ANY LK EFFECT ACROSS
VILAS CNTY WL CEASE AS DRIER AIR ADVECTS INTO THE RGN. EVEN THO
TEMPS MAY COOL A BIT...ANTICIPATE READINGS TO REMAIN ABOUT 5 DEGS
ABV NORMAL FOR EARLY FEB.
&&
.AVIATION...
LOW STRATUS AND FOG CONTINUE TO WREAK HAVOC ON FORECASTS OVER THE
WESTERN GREAT LAKES. SATELLITE IMAGERY DOESNT GIVE MUCH HOPE FOR
CLEARING THROUGH MIDDAY TOMORROW AS THE STRATUS AND FOG REMAIN PLACE
BACK TO MINNESOTA AND IOWA. HIGH PRESSURE WILL BUILD INTO THE REGION
TONIGHT LEAVING LIGHT WINDS IN PLACE. BOUNDARY LAYER TEMPS WARM A
COUPLE DEGREES TONIGHT WHICH WOULD HELP DISSIPATE THE CLOUDS...BUT
THE LIGHT WINDS AND HIGH DEWPOINTS WOULD ONLY PROMOTE FOG FORMATION.
AS A RESULT...SHOW LOWERING CIGS AND VSBYS LATE TONIGHT INTO
TOMORROW MORNING...WHICH HAS BEEN THE TREND UPSTREAM THE PAST COUPLE
DAYS. WILL HAVE A WEAK UPPER LEVEL DISTURBANCE BRING A CHANCE OF
FLURRIES TO NORTHERN WISCONSIN BUT NOT CONFIDENT TO ADD SNOW TO RHI
AT THIS TIME.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/KALLAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1212 PM CST WED FEB 1 2012
.SHORT TERM...THIS AFTERNOON AND EVENING
1204 PM CST WED FEB 1 2012
GFS AND RUC MODEL SOUNDINGS CONTINUE TO SHOW THAT A STRONG
SUBSIDENCE INVERSION WILL ALLOW LITTLE MIXING TO TAKE PLACE ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA THROUGH AT LEAST 9 PM
TONIGHT. DUE TO THIS...EXTENDED THE DENSE FOG ADVISORY THROUGH
9 PM TONIGHT. AFTER WARDS IT APPEARS THAT A 925 MB FRONT WILL MOVE
EAST THROUGH THE AREA. THE GFS SOUNDINGS SUGGEST THAT THE WINDS
WILL INCREASE INTO THE 5 TO 10 KNOT RANGE AND THE LOW LEVEL
MOISTURE WILL SCOUR OUT. WITH ROAD TEMPERATURES GENERALLY IN THE
32 TO 34 DEGREE RANGE...NOT OVERLY CONCERNED ABOUT WIDESPREAD
BLACK ICING. HOWEVER WITH THE SURFACE TEMPERATURES BELOW FREEZING
DECIDED TO MENTION THAT THERE MAY BE A POSSIBILITY FOR SOME PATCHY
BLACK ICE.
WITH THE EXTENSIVE CLOUDS AND LITTLE WARM AIR ADVECTION...LOWERED
TEMPERATURES A FEW MORE DEGREES WITH THE LATEST UPDATE.
.LONG TERM...SATURDAY THROUGH TUESDAY
320 AM CST WED FEB 1 2012
01.00Z MEDIUM RANGE MODEL CONSENSUS SLOWLY IMPROVING IN THE DAY 4-7
TIME-FRAME...BUT STILL PLENTY OF DIFFERENCES AND POOR RUN-TO-RUN
CONSISTENCY BY SAT. MODEL DIFFERENCES RESULT IN SIGNIFICANT
SENSIBLE WEATHER DIFFERENCES FOR PARTS OR ALL OF THE FCST AREA
SAT/SUN. INTERESTING THAT GFS WITH THE MOST NORTHERLY SOLUTION OF
THE 31.00Z RUNS IS NOW THE MORE SOUTHERLY SOLUTION. THE ECMWF HAS
FLIPPED THESE ROLES TOO AND IS NOW ONE OF THE MORE NORTHERLY
SOLUTIONS. NEEDLESS TO SAY...FCST CONFIDENCE BY SAT/SUN ON THE LOW
SIDE. GIVEN THE FLIP-FLOPPING OF THE MODELS AND BELOW AVERAGE RUN-
TO-RUN CONSISTENCY...NOT WILLING TO POINT TO ANY ONE DETERMINISTIC
MODEL AS A PREFERRED CHOICE FOR THE UPCOMING WEEKEND. USED THE
MODEL/ENSEMBLE CONSENSUS FOR SAT/SUN...WITH 20 TO 40 PERCENT SNOW OR
-RA/-SN CHANCES...HIGHEST ACROSS THE SOUTH END OF THE FCST AREA.
MON/TUE TREND DRY WITH A DRIER WEST/NORTHWEST FLOW SPREADING ACROSS
THE UPPER MIDWEST. HOWEVER CONFIDENCE NOT HIGH HERE EITHER WITH
OUTCOME OF SAT/SUN TO WEIGH INTO FLOW EVOLUTION FOR EARLY NEXT
WEEK...AND MODELS SHOWING POTENTIAL FOR A NORTHWEST FLOW SHORTWAVE
OR TWO TO DROP INTO/ACROSS THE REGION. BETTER CONFIDENCE FOR TEMPS
TO REMAIN ABOVE NORMAL FOR SAT-TUE WITH ARCTIC AIR REMAINING WELL
NORTH IN CANADA.
&&
.AVIATION...THROUGH 18Z THURSDAY
1204 PM CST WED FEB 1 2012
WITH THE GFS AND RUC MODEL SOUNDINGS CONTINUING TO SUGGEST THAT
THE LOW LEVEL INVERSION WILL REMAIN IN PLACE THROUGH 02.03Z.
EXTENDED THE DENSE FOG AT KRST THROUGH THIS TIME PERIOD...AND THEN
WENT WITH A GRADUAL IMPROVEMENT IN BOTH VISIBILITIES AND CEILINGS.
MEANWHILE AT KLSE...STILL NOT QUITE SURE WHETHER THE DENSE FOG
WILL MOVE INTO THIS AREA. THE MODELS SUGGEST THAT THIS MAY MOVE
MORE NORTHEAST AND BE FOUND MAINLY ALONG AND NORTH OF THE
INTERSTATE 94 CORRIDOR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1204 PM CST WED FEB 1 2012
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ079-
086>088-094>096.
IA...DENSE FOG ADVISORY UNTIL 9 PM CST THIS EVENING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM....RRS
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1020 AM CST WED FEB 1 2012
.AVIATION/18Z TAFS/...THE BACK EDGE OF THE STRATUS...CURRENTLY
OVER NORTHWEST IOWA... SOUTHWEST MINNESOTA AND NORTHEAST NORTH
DAKOTA...ISN/T SHOWING MUCH...IF ANY...PROGRESSION EASTWARD. WITH
LIGHT WINDS AND NO REAL CLEARING MECHANISM...THE CLOUDS WILL
LIKELY STICK AROUND THROUGH THE EVENING HOURS...AND POSSIBLY INTO
TOMORROW. THE QUESTION IS JUST WHEN THE CLOUDS WILL MOVE OUT OF
THE AREA. ALSO...DENSE FOG JUST TO THE WEST OF THE
MISSISSIPPI...IN NORTHEAST IOWA AND SOUTHEAST MINNESOTA...IS
HOLDING STRONG. VISIBILITIES IN THIS AREA ARE DOWN TO A QUARTER OF
A MILE. IF MORE PREVALENT WESTERLY WINDS DEVELOP THIS AFTERNOON WE
COULD SEE THAT FOG MAKE IT ACROSS THE MISSISSIPPI AND INTO SOUTH
CENTRAL WISCONSIN. THE PROGS DO IN FACT SHOW 1000-925 MILLIBAR
WINDS BECOMING MORE WESTERLY INTO TONIGHT...SO VSBYS SUGGESTED
MET/MAV GUIDANCE MAY BE TOO OPTIMISTIC TONIGHT INTO THURSDAY
MORNING.
MEB/PC
&&
.PREV DISCUSSION... /ISSUED 327 AM CST WED FEB 1 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
WEAK COLD AIR ADVECTION STRATUS HAS SETTLED OVER SRN WI DURING
THE NIGHT. TAMDAR ASCENT SOUNDINGS FROM KMSP CONFIRM 00Z KMPX
SOUNDING SHOWING CLOUDS ABOUT 500-1000FT THICK...WITH SOME OF THE
MOISTURE IN AS WELL AS BELOW THE SUBSIDENCE INVERSION WITH DRIER
AIR ALOFT. UPSTREAM LOW LEVEL FLOW WEAK VCNTY OF LOW LEVEL RIDGING
AND BACK EDGE OF LOW CLOUDS IN WRN MN NOT MAKING MUCH EWD PROGRESS
LAST FEW HOURS. 06Z NAM TRIES TO BREAK UP/THIN RH LATER THIS MRNG
OVER PORTIONS OF SRN WI WHILE RUC IS LESS OPTIMISTIC.
NOT SEEING MUCH SUBSIDENCE ALOFT ASSOCD WITH ANY SYNOPTIC FEATURE
TO HELP SCOUR LOW CLOUDS...AND WEAK UPSTREAM SHORT WAVE OVER ERN
DAKOTAS DOES BRING IN MID/HIGH CLOUDS LATER TODAY. WITH WEAK COLD
AIR ADVECTION CONTINUING THIS MRNG AND LIGHTER FLOW IN THE LOW
LEVELS SETTLING IN...WL BE MORE PESSIMISTIC WITH CLOUDS FOR TODAY.
SECOND SLIGHTLY STRONGER MID-LEVEL WAVE WL BRING MORE MID/HIGH
CLOUDS INTO THE AREA TONIGHT...AND VERY POSSIBLE THAT LOW CLOUDS
WILL STILL BE HANGING AROUND SRN WI.
HWVR...WL NEED TO WATCH FOR WEAK TERRAIN INDUCED SUBSIDENCE
HELPING TO THIN THE CLOUDS IN THE FAR ERN CWA LATER THIS MRNG AND
AFTN. NEVER THE LESS...WITH CLOUDY TO M/CLOUDY CONDITIONS EXPCD
TODAY AND W-NW SFC WNDS...KEPT TEMPS IN CHECK...CLOSER TO COOLER
MET GUIDANCE. DESPITE EXPCD CLOUD COVER TONIGHT...LIGHT BOUNDARY
LAYER WINDS SHOULD ALLOW AT LEAST PATCHY FOG TO DEVELOP.
SHORT TERM...THURSDAY THROUGH FRIDAY NIGHT...FORECAST CONFIDENCE
MEDIUM TO HIGH.
WEAK HIGH PRESSURE WILL SLOWLY MOVE EAST ACROSS THE REGION
THURSDAY AND THURSDAY NIGHT...BRINGING QUIET WEATHER TO THE AREA.
SOME MIDDLE OR HIGH CLOUDS MAY MOVE THROUGH THE AREA AT TIMES.
LIGHT WINDS AND LOW LEVEL MOISTURE THURSDAY NIGHT MAY LEAD TO SOME
FOG FORMATION...BUT MODELS HAVE BEEN OVERESTIMATING LOW LEVEL
MOISTURE QUITE A BIT THIS WINTER...SO WILL NOT MENTION IN FORECAST
YET. MILD TEMPERATURES WILL CONTINUE...WELL ABOVE SEASONAL
NORMALS.
LARGER HIGH PRESSURE ACROSS THE FAR NORTHERN PLAINS FRIDAY WILL
KEEP THE AREA DRY...WITH ANOTHER MILD DAY EXPECTED UNDER PARTLY
SUNNY SKIES.
LEE CYCLOGENESIS OCCURS IN THE SOUTHERN HIGH PLAINS THURSDAY NIGHT
INTO FRIDAY...AS AN UPPER LOW DEVELOPS ACROSS THE SOUTHERN ROCKIES
AND SHIFTS INTO THE SOUTHERN HIGH PLAINS. THE NAM/GFS/CANADIAN
MODELS ARE QUICKER WITH THE PROGRESSION OF THIS SYSTEM TO THE EAST
ACROSS THE CENTRAL PLAINS THAN THE ECMWF. THE ECMWF DEVELOPS A
DEEP CUTOFF LOW OVER NORTH CENTRAL KANSAS BY 12Z SATURDAY...WITH A
DEEP SURFACE LOW JUST TO THE EAST.
THE OTHER MODELS HAVE THE UPPER LOW ANYWHERE FROM SOUTH CENTRAL
KANSAS TO FAR SOUTHWEST IOWA...WITH THE SURFACE LOW ANYWHERE FROM
NORTHERN TO SOUTHWESTERN MISSOURI. GIVEN THE CONFIDENCE HPC HAS
HAD WITH THE ECMWF AND ECMWF ENSEMBLES WITH THIS SYSTEM...LEANED
TOWARDS IT AND KEPT MOST OF THE AREA DRY FRIDAY NIGHT. KEPT LOW
POPS IN THE FAR SOUTHWEST LATE FRIDAY NIGHT FOR CONTINUITY...BUT
MAY HAVE TO TAKE THESE OUT IN LATER FORECASTS IF SLOWER ECMWF
VERIFIES.
LONG TERM...SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE LOW.
MAJOR DIFFERENCES EXIST DURING THIS PERIOD BETWEEN THE ECMWF AND
GFS. THE GFS CONTINUES TO BE MORE PROGRESSIVE WITH THE UPPER LOW
SATURDAY INTO SATURDAY NIGHT...TAKING IT ACROSS SOUTHERN IOWA AND
CENTRAL ILLINOIS. ASSOCIATED SURFACE LOW MOVES QUICKLY EAST FROM
CENTRAL MISSOURI TO KENTUCKY. THIS TRACK BRINGS PRECIPITATION INTO
THE AREA SATURDAY INTO SATURDAY EVENING.
THE ECMWF REMAINS SLOWER AND DEEPER WITH THE UPPER LOW DURING THIS
TIME...KEEPING IT ACROSS THE CENTRAL PLAINS. SURFACE LOW OCCLUDES
AS IT BECOMES VERTICALLY STACKED WITH THE UPPER LOW. THIS SCENARIO
ALSO BRINGS LIGHT PRECIPITATION INTO MAINLY SOUTHERN PORTIONS OF
THE AREA. WILL CONTINUE TO USE CONSENSUS POPS AND TEMPERATURES FOR
THIS PERIOD...THOUGH WOULD LEAN MORE TOWARD THE SLOWER LOOK OF THE
ECMWF.
ECMWF TAKES UPPER LOW AND DEVELOPS AN OPEN WAVE OUT OF IT SUNDAY
NIGHT THROUGH MONDAY AS IT MOVES EAST THROUGH THE REGION. IT DOES
BRING LIGHT PRECIPITATION ACROSS THE AREA WITH IT. THE GFS IS DRY
WITH HIGH PRESSURE ACROSS THE AREA DURING THIS TIME. THEY BOTH
GENERALLY SHOW SOME COLD AIR ADVECTION LATER MONDAY INTO
TUESDAY...WITH THE ECMWF SHOWING STRONG COLD AIR ADVECTION TUESDAY
WITH A SHARP UPPER TROUGH MOVING THROUGH THE REGION. THE GFS IS
MUCH WEAKER WITH THE COLD ADVECTION. WILL CONTINUE TO USE
CONSENSUS POPS AND TEMPERATURES DURING THIS TIME. MILD
TEMPERATURES SHOULD CONTINUE DESPITE THE MODEL DIFFERENCES.
AVIATION/12Z TAFS/...
MVFR CIGS HAVE ENGULFED ALL OF SRN WI EARLY THIS MRNG. WILL
CONTINUE MVFR CIGS INTO THE AFTN...WITH LIGHTER WINDS IN WRN CWA
POSSIBLY ALLOWING CIGS TO FALL INTO IFR CATEGORY FOR A TIME AT
KMSN. FOR NOW WL TREND TOWARD CLOUDS THINNING THIS AFTN...BUT
CONFIDENCE LOW DUE TO ABOVE DISCUSSION. LIGHTER BOUNDARY LAYER
WINDS AND LINGERING LOW LEVEL MOISTURE SHOULD ALLOW PATCHY FOG TO
DEVELOP TONIGHT.
MARINE...
NORTHWEST WINDS WILL CONTINUE TO DIMINISH THIS MORNING AS THE
PRESSURE GRADIENT FURTHER WEAKENS. LIGHT WIND CONDITIONS ARE THEN
EXPECTED FOR AN EXTENDED PERIOD OF TIME FROM TONIGHT THROUGH
FRIDAY...UNTIL LOW PRESSURE BEGINS TO STRENGTHEN OVER THE CENTRAL
PLAINS AND MEANDER EWD OVER THE WEEKEND.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
THURSDAY THROUGH TUESDAY...WOOD