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