Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 11/25/11
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1131 PM CST TUE NOV 22 2011
.AVIATION...
EXPECT LOW CLOUDS IN N AR TO BEGIN BREAKING UP BY MID MORNING.
WILL HAVE TO WATCH FOR BR DEVELOPMENT WHERE CLOUDS HAVE CLEARED
OUT. OTHERWISE...MOSTLY CLEAR SKIES FOR THIS FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 855 PM CST TUE NOV 22 2011/
DISCUSSION...
OVERALL FORECAST ON TRACK. WILL FINE TUNE CLOUDS AND TEMPS IN
OVERNIGHT PERIOD BASED ON LATEST TRENDS. STRATUS DECK CONTINUES TO
ROTATE AROUND THE SURFACE LOW BACK TO AR AND DO EXPECT SOME
CONTINUED CLOUDS OVER NORTHERN TO NE AR. WILL FINE TUNE NORTH AR THE
MOST. BACK EDGE IS SLOWLY MOVING EAST BUT WILL BE SLOW...WHILE DOWN
SLOP OFF THE OZARKS AND OUACHITAS TO HELP DISPERSE CLOUDS. WINDS
WILL REMAIN UP A BIT TONIGHT AND SHOULD HELP MIX SOME OF THE
MOISTURE OUT. 00Z KLZK SOUNDING SHOWED MOISTURE TRAPPED AROUND 1K FT
TO 5K FT. PARTLY CLOUDY TO CLEARING IS EXPECTED MAINLY CENTRAL AND
ESPECIALLY SOUTH. SURFACE RIDGE IS BUILDING SE AND BRINGING COOLER
AND DRIER AIR. (59)
PREV DISCUSSION... /ISSUED 549 PM CST TUE NOV 22 2011/
AVIATION...
MVFR CLOUDS STILL PREVALENT ACROSS THE STATE...WITH THE MOST
WIDESPREAD AREA OF MVFR CIGS IN THE HIGHER TERRAIN OF WESTERN AND
NORTHERN ARKANSAS. MOS GUIDANCE NOT VERY KEEN ON CHANCES FOR
LINGERING CIGS...BUT RUC DATA AS WELL AS A FAIRLY EXPANSIVE
STRATUS FIELD UPSTREAM OF ARKANSAS SEEN ON SATELLITE IMAGERY WOULD
SUGGEST OTHERWISE. HAVE GONE WITH MVFR/IFR CIGS FOR KHRO AND KBPK
THROUGH THE NIGHT THEN CLEARING OUT A FEW HOURS AFTER DAYBREAK
TOMORROW. ALSO INCLUDED MVFR CIGS AT KHOT AS IT IS CLOSE ENOUGH TO
THE HIGH TERRAIN OF THE OUACHITAS TO LIKELY HOLD ON TO CIGS.
FOR KLIT AND KPBF...VFR CONDITIONS ARE EXPECTED OVERNIGHT AS
DRYING DOWNSLOPE FLOW OFF THE OUACHITAS AND OZARKS HOLDS CLOUDS AT
BAY. FINALLY...KLLQ SHOULD SEE IMPROVEMENT TO VFR CONDITIONS BY
04Z AND THEN HOLD AT VFR LEVELS THE REST OF THE TAF PERIOD. WINDS
WILL BE LIGHT NORTHWEST THROUGH THE PERIOD.
PREV DISCUSSION... /ISSUED 308 PM CST TUE NOV 22 2011/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
A COLD FRONT PUSHED TO THE EAST TODAY...TAKING WIDESPREAD
HEAVY RAIN OUT OF ARKANSAS. HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE WEST OVERNIGHT/WEDNESDAY. THERE WERE
ALREADY SOME BREAKS IN THE CLOUDS THIS AFTERNOON...WITH CLOUDS
CONTINUING TO DECREASE TONIGHT.
DRY CONDITIONS WILL BE NOTED THROUGH FRIDAY. TEMPERATURES WILL
BE CLOSE TO NORMAL INITIALLY. READINGS WILL CLIMB ABOVE NORMAL AS
HIGH PRESSURE MOVES AWAY AS THE WEEK PROGRESSES AND SOUTHERLY WINDS
KICK IN.
LATE FRIDAY/FRIDAY NIGHT...A STORM SYSTEM AND COLD FRONT WILL
APPROACH FROM THE WEST. CLOUDS WILL INCREASE...WITH GOOD CHANCES
FOR SHOWERS AND THUNDERSTORMS SPREADING INTO ARKANSAS.
LONG TERM...SATURDAY THROUGH TUESDAY
THE LONG TERM PD WILL BEGIN WITH A COLD FRONT SWEEPING THROUGH THE
STATE AND USHERING IN MUCH COLDER AIR FOR THE REMAINDER OF THE
HOLIDAY WEEKEND. HAVE GONE WITH LIKELY POPS ON SAT AND MENTIONED
THUNDERSTORMS THOUGH DO NOT EXPECT MUCH IN THE WAY OF SVR WX AS MSTR
RETURN REMAINS LIMITED. DUE TO ITS QUICK MOTION...THIS SYSTEM SHOULD
NOT DROP AS MUCH RAIN AS THE SYSTEM THAT JUST DEPARTED THE STATE
THOUGH 1 TO 2 INCH AMOUNTS CANNOT BE RULED OUT.
SUNDAY THROUGH TUESDAY WILL FEATURE BELOW NORMAL TEMPS AND STILL
THAT OUTSIDE SHOT OF A SNOW FLURRY OR TWO...MAINLY IN NORTHEASTERN
AR SUN NIGHT AND MON. THIS STILL LOOKS LIKE A VERY LOW PROBABILITY
EVENT...SO HAVE NOT YET INTRODUCED ANY OF THE WINTRY STUFF TO THE
GRIDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 58 42 59 39 / 10 10 0 0
CAMDEN AR 59 45 64 42 / 10 10 0 0
HARRISON AR 50 40 59 38 / 0 10 0 0
HOT SPRINGS AR 63 43 62 41 / 10 10 0 0
LITTLE ROCK AR 62 43 61 41 / 10 10 0 0
MONTICELLO AR 66 46 64 42 / 10 10 0 0
MOUNT IDA AR 62 41 63 41 / 10 10 0 0
MOUNTAIN HOME AR 52 41 59 38 / 10 10 0 0
NEWPORT AR 61 42 60 40 / 10 10 0 0
PINE BLUFF AR 64 45 63 41 / 10 10 0 0
RUSSELLVILLE AR 58 40 61 40 / 10 10 0 0
SEARCY AR 63 42 60 40 / 10 10 0 0
STUTTGART AR 65 44 62 41 / 10 10 0 0
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...28
AREA FORECAST DISCUSSION
NWS ALBANY NY
1018 PM EST THU NOV 24 2011
.SYNOPSIS...
THE WEATHER PATTERN WILL BE TRANQUIL FOR THIS HOLIDAY WEEKEND WITH
HIGH PRESSURE REMAINING IN CONTROL ALONG THE EASTERN SEABOARD.
TEMPERATURES WILL SLOWLY MODERATE TO ABOVE NORMAL AS SOUTHERLY WINDS
INCREASE. THE NEXT CHANCE FOR SHOWERS ARRIVES LATE SUNDAY INTO
MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 1000 PM EST...THE IR SATELLITE PICTURE SHOWS SOME THIN
CIRRUS MOVING ACROSS ERN NY. NORTH AND WEST OF THE CAPITAL REGION...
SOME STRATUS IS STILL LINGERING OVER THE ADIRONDACKS. THE MOSTLY
CLEAR SKIES AND LIGHT TO CALM WINDS HAVE ALLOWED SOME PATCHY
RADIATIONAL FOG FORMATION OVER MUCH OF THE FCST AREA. THE SFC
SOILS ARE STILL A BIT WET FROM THE HVY RAINFALL ON TUESDAY NIGHT-WED.
THE FOG IS MOST ROBUST OVER THE LAKE GEORGE REGION...AND EAST OF
THE SRN GREEN MTNS. WE HAVE ADDED PATCHY FOG OVERNIGHT FOR
LOCATIONS LESS THAN 1000 FEET ACROSS ERN NY AND WRN NEW ENGLAND.
TEMPS VARY WIDELY ACROSS THE REGION WITH MINS REACHED OR EXCEEDED
OVER THE LAKE GEORGE REGION...AND THE BERKSHIRES. WE HAVE BROUGHT
MINS DOWN A FEW DEGREES WHERE IT RADIATED QUICKLY OVER THE LAKE
GEORGE REGION...NRN AND CNTRL TACONICS...AND THE BERKSHIRES.
EXPECT LOWS TO RANGE FROM THE M20S TO M30S ACROSS THE REGION. A
WEAK THERMAL TROUGH WILL MOVE THROUGH THE REGION OVERNIGHT...AND
WE ARE SEEING WINDS INCREASE FROM THE S/SW OVER W-CNTRL NY. TEMPS
MAY ACTUALLY CREEP UP A FEW DEGREES TOWARD SUNRISE.
PREVIOUS NEAR TERMS...
AS OF 630 PM EST...HAPPY THANKSGIVING TO ALL ! HIGH PRESSURE AT
THE SFC CONTINUES TO RIDGE IN FROM THE TN VALLEY AND THE MID
ATLANTIC REGION. A WEAK IMPULSE IN THE H500 W/NW FLOW ALOFT
CONTINUES TO MOVE ACROSS THE ERN GREAT LAKES REGION...AND UPSTATE
NY. THE STRATUS IS HANGING TOUGH ON THE 11-3.9 MICRON SATELLITE
LOOP NORTH AND WEST OF THE CAPITAL REGION. WE INCREASED THE CLOUD
COVER THROUGH MIDNIGHT OVER THE SRN AND WRN DACKS. THE NAM12 MODEL
SOUNDINGS...AND RH PROFILES INDICATE THIS STRATUS WILL HANG ON.
THE OTHER ISSUE TO DEAL WITH IS THE SKIES CLEARING...AND THE WINDS
GOING LIGHT TO CALM FROM THE HUDSON RIVER VALLEY EASTWARD. KGFL HAS
DROPPED TO ABOUT 30F WITH SOME PATCHY FOG FORMING. WE ADDED SOME
PATCHY FOG TO THE KGFL GENERAL AREA...AND TO THE CT RIVER VALLEY
EAST OF THE SRN GREEN MTNS. HOURLY TRENDS WERE REDONE BASED ON
OBSERVATIONS FOR T/TD/RH/APPARENT TEMPS. ASIDE FOR A FEW CIRRUS
FROM THE CAPITAL REGION SOUTH AND EAST OVERNIGHT...EXPECT TEMPS TO
COOL INTO THE U20S TO M30S.
PREVIOUS NEAR TERM...
STRATUS DECK WAS ALONG THE I90 CORRIDOR AS OF 19Z. THIS CLOUD DECK
CONTINUES TO SLOWLY ERODE AND MIGRATE NORTHWARD THIS AFTERNOON.
NCEP MODEL SUITE AND HOURLY RUC13 LOW LEVEL RH FIELDS SUGGEST THIS
STRATUS DECK SHOULD CONTINUE TO LIFT NORTHWARD AND ERODE FURTHER.
MEANWHILE...WARM ADVECTION ALOFT AND ITS ASSOCIATED HIGH AND SOME
MID LEVEL CLOUDS ARE QUICKLY MOVING ACROSS NEW ENGLAND AND
PORTIONS OF UPSTATE NEW YORK. THIS TOO IS EXPECTED TO SLIDE
OFFSHORE TONIGHT LEAVING BEHIND A PTCLOUDY-MOCLEAR SKIES.
BASED ON CURRENT DEWPOINTS...MOS TEMPERATURES LOOK A BIT COOL AND
HAVE FOLLOWED WARMER OVERNIGHT TRENDS WITHIN THE LAV/LAMP
GUIDANCE.
LARGE AREA OF HIGH PRESSURE...CENTERED OVER THE SOUTHEAST
CONUS...WILL BE THE DOMINANT PLAYER FOR THIS NEAR TERM AND INTO
THE SHORT TERM.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
THIS LARGE AREA OF HIGH PRESSURE WILL KEEP THE WEATHER QUIET EAST
OF THE MISSISSIPPI RIVER THROUGH THIS SHORT TERM PERIOD. IN
FACT...RATHER PRONOUNCED WEST-SOUTHWEST FLOW ALONG WITH MILD MID
LEVEL TEMPS WILL RESULT IN TEMPERATURES CLIMBING TOWARD OR
EXCEEDING 10 DEGREES ABOVE CLIMATOLOGY /IN ADDITION...DOWNSLOPING
MAY ENHANCE THESE TEMPS INTO THE VALLEY LOCATIONS/. THE ONLY
COMPLICATION COULD BE SOME OVERNIGHT SHALLOW BR/FG AND A POTENTIAL
FOR SOME LOW LEVEL STRATUS DEVELOPMENT. IN ADDITION...WITH THE
ONGOING WARM ADVECTION...SOME HIGH AND MID LEVEL CLOUD COVER MAY
MOVE ACROSS THE SKY THOUGH THIS PERIOD. EITHER WAY...THE WEATHER
SHOULD HAVE MINIMAL IMPACT TO HOLIDAY WEEKEND TRAVELS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ACTIVE WEATHER PATTERN EXPECTED THROUGH THE LONG TERM...BUT MODEL
GUIDANCE HAS DIFFERING SOLUTIONS...SO CONFIDENCE IS LOW. WENT WITH
HPC GUIDANCE.
SFC LOW APPROACHING FROM THE GREAT LAKES REGION SUNDAY MORNING. 12Z
GFS...ECMWF AND GFSENSEMBLE MEMBERS HAVE NOT AGREED UPON A
TRACK...SPEED...OR QPF AMOUNTS. ECMWF HAS THE MORE PROGRESSIVE AND
NORTHERLY TRACK OF SFC LOW...WITH THE COLD FRONT AND PRECIP
ASSOCIATED WITH THE LOW MOVING THROUGH THE FA LATE SUNDAY THROUGH
LATE MONDAY...WITH QPF AMOUNTS AROUND HALF AN INCH OR LESS.
ASSOCIATED UPPER LEVEL POSITIVELY TILTED TROUGH REMAINS OPEN IN
ECMWF.
MEANWHILE...GFS DEVELOPS A CLOSE LOW WITHIN THE UPPER LEVEL TROUGH.
AS THIS TROUGH APPEARS TO HAVE A NEUTRAL TILT...GFS KEEPS IT SLOW
MOVING OVER THE GREAT LAKES REGION...WHERE THE UPPER LEVEL LOW
PRESSURE CENTER REFORMS FURTHER NORTH SUNDAY NIGHT. THE TROUGH
BECOMES NEGATIVELY TILTED BEFORE A PIECE OF SOUTHERLY ENERGY BREAKS
OFF...TRAVELING TOWARDS THE OBX AHEAD OF THE MAIN TROUGH...BY
TUESDAY NIGHT. QPF AMOUNTS UP TO 2 INCHES WITH THE GFS.
CHANCE FOR PRECIP POSSIBLE THROUGH TUESDAY NIGHT/WEDNESDAY WITH GFS
ENSEMBLE MEMBERS SLOWLY MOVE SFC LOW NORTHWARD TOWARDS JAMES BAY.
ALL GUIDANCE SHOW HIGH PRESSURE BUILDING IN JUST SOUTH OF THE
REGION...BUT NO AGREEMENT ON WHEN OR FOR HOW LONG. HPC HAS HIGH
PRESSURE WEDNESDAY INTO THURSDAY.
TEMPS ABOUT 10 DEGREES ABOVE NORMAL TO START THE PERIOD...TRENDING
COOLER TO ABOUT NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL CONTINUE TO RIDGE IN FROM THE MID ATLANTIC
REGION OVERNIGHT INTO TOMORROW.
MVFR CONDITIONS WILL PREVAIL FROM KALB SOUTH OVERNIGHT WITH SOME
PATCHY MIST...BUT SOME IFR/MVFR MIST/STRATUS WILL LIKELY BE AN
ISSUE AT KGFL OVERNIGHT. THE SKIES HAVE CLEARED...WITH LIGHT TO
CALM WINDS AND SOME PATCHY MVFR MIST HAS ALREADY DEVELOPED AT
KGFL. WE WILL CONTINUE THIS TREND OF MVFR/IFR MIST...AND POSSIBLY
SOME MVFR STRATUS PRIOR TO 12Z/FRI THERE. KALB SOUTH TO KPOU
SHOULD RISE QUICKLY TO VFR LEVELS BY 12Z.
THE SKIES WILL BE MOSTLY CLEAR IN THE LATE MORNING THROUGH THE
AFTERNOON WITH VFR CONDITIONS PREVAILING DUE TO THE STRONG
SUBSIDENCE FROM THE ANTICYCLONE.
THE WINDS WILL BE LIGHT TO CALM OVERNIGHT. THEY WILL INCREASE FROM
THE S/SW AT 5-10 KTS DURING THE LATE MORNING AND AFTERNOON.
OUTLOOK...
FRIDAY NIGHT-SAT NIGHT...VFR. NO SIG WX.
SUN...MAINLY VFR. INCREASING CLDS. CHC PM -SHRAS.
SUN NIGHT-TUE...MVFR/IFR WITH CHC -SHRAS.
&&
.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH MOST OF THE LONG HOLIDAY WEEKEND
AS HIGH PRESSURE DOMINATES. OUR NEXT CHANCES FOR WET WEATHER WILL
RETURN LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS A LOW PRESSURE
SYSTEM APPROACHES AND MOVES ACROSS THE REGION. THERE IS MUCH
UNCERTAINTY WITH REGARDS TO THE SYSTEM AS THERE IS A LARGE SPREAD
IN THE MODEL GUIDANCE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
2011 HAS MOVED UP INTO FIFTH PLACE FOR WETTEST YEARS ON RECORD
FOR ALBANY NEW YORK.
WETTEST YEARS - ALBANY NY - SINCE 1820
1) 55.78 INCHES 1871
2) 55.81 INCHES 1870
3) 51.83 INCHES 1850
4) 49.80 INCHES 1827
5) 49.75 INCHES THROUGH NOVEMBER 23ND
6) 49.37 INCHES 1878
7) 48.35 INCHES 1843
8) 48.22 INCHES 1848
9) 47.79 INCHES 2008
10) 47.72 INCHES 2005
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...BGM/WASULA
SHORT TERM...BGM
LONG TERM...KGM
AVIATION...WASULA
HYDROLOGY...BGM
CLIMATE...IAA
AREA FORECAST DISCUSSION...CORRECTED
NWS ALBANY NY
646 PM EST THU NOV 24 2011
.SYNOPSIS...
THE WEATHER PATTERN WILL BE TRANQUIL FOR THIS HOLIDAY WEEKEND WITH
HIGH PRESSURE REMAINING IN CONTROL ALONG THE EASTERN SEABOARD.
TEMPERATURES WILL SLOWLY MODERATE TO ABOVE NORMAL AS SOUTHERLY WINDS
INCREASE. THE NEXT CHANCE FOR SHOWERS ARRIVES LATE SUNDAY INTO
MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 630 PM EST...HAPPY THANKSGIVING TO ALL ! HIGH PRESSURE AT
THE SFC CONTINUES TO RIDGE IN FROM THE TN VALLEY AND THE MID
ATLANTIC REGION. A WEAK IMPULSE IN THE H500 W/NW FLOW ALOFT
CONTINUES TO MOVE ACROSS THE ERN GREAT LAKES REGION...AND UPSTATE
NY. THE STRATUS IS HANGING TOUGH ON THE 11-3.9 MICRON SATELLITE
LOOP NORTH AND WEST OF THE CAPITAL REGION. WE INCREASED THE CLOUD
COVER THROUGH MIDNIGHT OVER THE SRN AND WRN DACKS. THE NAM12 MODEL
SOUNDINGS...AND RH PROFILES INDICATE THIS STRATUS WILL HANG ON.
THE OTHER ISSUE TO DEAL WITH IS THE SKIES CLEARING...AND THE WINDS
GOING LIGHT TO CALM FROM THE HUDSON RIVER VALLEY EASTWARD. KGFL HAS
DROPPED TO ABOUT 30F WITH SOME PATCHY FOG FORMING. WE ADDED SOME
PATCHY FOG TO THE KGFL GENERAL AREA...AND TO THE CT RIVER VALLEY
EAST OF THE SRN GREEN MTNS. HOURLY TRENDS WERE REDONE BASED ON
OBSERVATIONS FOR T/TD/RH/APPARENT TEMPS. ASIDE FOR A FEW CIRRUS
FROM THE CAPITAL REGION SOUTH AND EAST OVERNIGHT...EXPECT TEMPS TO
COOL INTO THE U20S TO M30S.
PREVIOUS NEAR TERM...
STRATUS DECK WAS ALONG THE I90 CORRIDOR AS OF 19Z. THIS CLOUD DECK
CONTINUES TO SLOWLY ERODE AND MIGRATE NORTHWARD THIS AFTERNOON.
NCEP MODEL SUITE AND HOURLY RUC13 LOW LEVEL RH FIELDS SUGGEST THIS
STRATUS DECK SHOULD CONTINUE TO LIFT NORTHWARD AND ERODE FURTHER.
MEANWHILE...WARM ADVECTION ALOFT AND ITS ASSOCIATED HIGH AND SOME
MID LEVEL CLOUDS ARE QUICKLY MOVING ACROSS NEW ENGLAND AND
PORTIONS OF UPSTATE NEW YORK. THIS TOO IS EXPECTED TO SLIDE
OFFSHORE TONIGHT LEAVING BEHIND A PTCLOUDY-MOCLEAR SKIES.
BASED ON CURRENT DEWPOINTS...MOS TEMPERATURES LOOK A BIT COOL AND
HAVE FOLLOWED WARMER OVERNIGHT TRENDS WITHIN THE LAV/LAMP
GUIDANCE.
LARGE AREA OF HIGH PRESSURE...CENTERED OVER THE SOUTHEAST
CONUS...WILL BE THE DOMINANT PLAYER FOR THIS NEAR TERM AND INTO
THE SHORT TERM.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
THIS LARGE AREA OF HIGH PRESSURE WILL KEEP THE WEATHER QUIET EAST
OF THE MISSISSIPPI RIVER THROUGH THIS SHORT TERM PERIOD. IN
FACT...RATHER PRONOUNCED WEST-SOUTHWEST FLOW ALONG WITH MILD MID
LEVEL TEMPS WILL RESULT IN TEMPERATURES CLIMBING TOWARD OR
EXCEEDING 10 DEGREES ABOVE CLIMATOLOGY /IN ADDITION...DOWNSLOPING
MAY ENHANCE THESE TEMPS INTO THE VALLEY LOCATIONS/. THE ONLY
COMPLICATION COULD BE SOME OVERNIGHT SHALLOW BR/FG AND A POTENTIAL
FOR SOME LOW LEVEL STRATUS DEVELOPMENT. IN ADDITION...WITH THE
ONGOING WARM ADVECTION...SOME HIGH AND MID LEVEL CLOUD COVER MAY
MOVE ACROSS THE SKY THOUGH THIS PERIOD. EITHER WAY...THE WEATHER
SHOULD HAVE MINIMAL IMPACT TO HOLIDAY WEEKEND TRAVELS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ACTIVE WEATHER PATTERN EXPECTED THROUGH THE LONG TERM...BUT MODEL
GUIDANCE HAS DIFFERING SOLUTIONS...SO CONFIDENCE IS LOW. WENT WITH
HPC GUIDANCE.
SFC LOW APPROACHING FROM THE GREAT LAKES REGION SUNDAY MORNING. 12Z
GFS...ECMWF AND GFSENSEMBLE MEMBERS HAVE NOT AGREED UPON A
TRACK...SPEED...OR QPF AMOUNTS. ECMWF HAS THE MORE PROGRESSIVE AND
NORTHERLY TRACK OF SFC LOW...WITH THE COLD FRONT AND PRECIP
ASSOCIATED WITH THE LOW MOVING THROUGH THE FA LATE SUNDAY THROUGH
LATE MONDAY...WITH QPF AMOUNTS AROUND HALF AN INCH OR LESS.
ASSOCIATED UPPER LEVEL POSITIVELY TILTED TROUGH REMAINS OPEN IN
ECMWF.
MEANWHILE...GFS DEVELOPS A CLOSE LOW WITHIN THE UPPER LEVEL TROUGH.
AS THIS TROUGH APPEARS TO HAVE A NEUTRAL TILT...GFS KEEPS IT SLOW
MOVING OVER THE GREAT LAKES REGION...WHERE THE UPPER LEVEL LOW
PRESSURE CENTER REFORMS FURTHER NORTH SUNDAY NIGHT. THE TROUGH
BECOMES NEGATIVELY TILTED BEFORE A PIECE OF SOUTHERLY ENERGY BREAKS
OFF...TRAVELING TOWARDS THE OBX AHEAD OF THE MAIN TROUGH...BY
TUESDAY NIGHT. QPF AMOUNTS UP TO 2 INCHES WITH THE GFS.
CHANCE FOR PRECIP POSSIBLE THROUGH TUESDAY NIGHT/WEDNESDAY WITH GFS
ENSEMBLE MEMBERS SLOWLY MOVE SFC LOW NORTHWARD TOWARDS JAMES BAY.
ALL GUIDANCE SHOW HIGH PRESSURE BUILDING IN JUST SOUTH OF THE
REGION...BUT NO AGREEMENT ON WHEN OR FOR HOW LONG. HPC HAS HIGH
PRESSURE WEDNESDAY INTO THURSDAY.
TEMPS ABOUT 10 DEGREES ABOVE NORMAL TO START THE PERIOD...TRENDING
COOLER TO ABOUT NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL CONTINUE TO RIDGE IN FROM THE MID ATLANTIC
REGION OVERNIGHT INTO TOMORROW.
VFR CONDITIONS WILL PREVAIL FROM KALB SOUTH OVERNIGHT...BUT SOME
IFR/MVFR MIST/STRATUS WILL LIKELY BE AN ISSUE AT KGFL OVERNIGHT.
THE SKIES HAVE CLEARED...WITH LIGHT TO CALM WINDS AND SOME PATCHY
MVFR MIST HAS ALREADY DEVELOPED AT KGFL. WE WILL CONTINUE THIS
TREND OF MVFR/IFR MIST...AND POSSIBLY SOME MVFR STRATUS PRIOR TO
12Z/FRI.
THE SKIES WILL BE MOSTLY CLEAR IN THE LATE MORNING THROUGH THE
AFTERNOON WITH VFR CONDITIONS PREVAILING DUE TO THE STRONG
SUBSIDENCE FROM THE ANTICYCLONE.
THE WINDS WILL BE LIGHT TO CALM OVERNIGHT. THEY WILL INCREASE FROM
THE S/SW AT 5-10 KTS DURING THE LATE MORNING AND AFTERNOON.
OUTLOOK...
FRIDAY NIGHT-SAT NIGHT...VFR. NO SIG WX.
SUN...MAINLY VFR. INCREASING CLDS. CHC PM -SHRAS.
SUN NIGHT-TUE...MVFR/IFR WITH CHC -SHRAS.
&&
.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH MOST OF THE LONG HOLIDAY WEEKEND
AS HIGH PRESSURE DOMINATES. OUR NEXT CHANCES FOR WET WEATHER WILL
RETURN LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS A LOW PRESSURE
SYSTEM APPROACHES AND MOVES ACROSS THE REGION. THERE IS MUCH
UNCERTAINTY WITH REGARDS TO THE SYSTEM AS THERE IS A LARGE SPREAD
IN THE MODEL GUIDANCE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
2011 HAS MOVED UP INTO FIFTH PLACE FOR WETTEST YEARS ON RECORD
FOR ALBANY NEW YORK.
WETTEST YEARS - ALBANY NY - SINCE 1820
1) 55.78 INCHES 1871
2) 55.81 INCHES 1870
3) 51.83 INCHES 1850
4) 49.80 INCHES 1827
5) 49.75 INCHES THROUGH NOVEMBER 23ND
6) 49.37 INCHES 1878
7) 48.35 INCHES 1843
8) 48.22 INCHES 1848
9) 47.79 INCHES 2008
10) 47.72 INCHES 2005
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...BGM/WASULA
SHORT TERM...BGM
LONG TERM...KGM
AVIATION...WASULA
HYDROLOGY...BGM
CLIMATE...IAA
AREA FORECAST DISCUSSION
NWS ALBANY NY
639 PM EST THU NOV 24 2011
.SYNOPSIS...
THE WEATHER PATTERN WILL BE TRANQUIL FOR THIS HOLIDAY WEEKEND WITH HIGH
PRESSURE REMAINING IN CONTROL ALONG THE EASTERN SEABOARD. TEMPERATURES
WILL SLOWLY MODERATE TO ABOVE NORMAL AS SOUTHERLY WINDS INCREASE.
THE NEXT CHANCE FOR SHOWERS ARRIVES LATE SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 630 PM EDT...HAPPY THANKSGIVING TO ALL ! HIGH PRESSURE AT
THE SFC CONTINUES TO RIDGE IN FROM THE TN VALLEY AND THE MID
ATLANTIC REGION. A WEAK IMPULSE IN THE H500 W/NW FLOW ALOFT
CONTINUES TO MOVE ACROSS THE ERN GREAT LAKES REGION...AND UPSTATE
NY. THE STRATUS IS HANGING TOUGH ON THE 11-3.9 MICRON SATELLITE
LOOP NORTH AND WEST OF THE CAPITAL REGION. WE INCREASED THE CLOUD
COVER THROUGH MIDNIGHT OVER THE SRN AND WRN DACKS. THE NAM12 MODEL
SOUNDINGS...AND RH PROFILES INDICATE THIS STRATUS WILL HANG ON.
THE OTHER ISSUE TO DEAL WITH IS THE SKIES CLEARING...AND THE WINDS
GOING LIGHT TO CALM FROM THE HUDSON RIVER VALLEY EASTWARD. KGFL HAS
DROPPED TO ABOUT 30F WITH SOME PATCHY FOG FORMING. WE ADDED SOME
PATCHY FOG TO THE KGFL GENERAL AREA...AND TO THE CT RIVER VALLEY
EAST OF THE SRN GREEN MTNS. HOURLY TRENDS WERE REDONE BASED ON
OBSERVATIONS FOR T/TD/RH/APPARENT TEMPS. ASIDE FOR A FEW CIRRUS
FROM THE CAPITAL REGION SOUTH AND EAST OVERNIGHT...EXPECT TEMPS TO
COOL INTO THE U20S TO M30S.
PREVIOUS NEAR TERM...
STRATUS DECK WAS ALONG THE I90 CORRIDOR AS OF 19Z. THIS CLOUD DECK
CONTINUES TO SLOWLY ERODE AND MIGRATE NORTHWARD THIS AFTERNOON.
NCEP MODEL SUITE AND HOURLY RUC13 LOW LEVEL RH FIELDS SUGGEST THIS
STRATUS DECK SHOULD CONTINUE TO LIFT NORTHWARD AND ERODE FURTHER.
MEANWHILE...WARM ADVECTION ALOFT AND ITS ASSOCIATED HIGH AND SOME
MID LEVEL CLOUDS ARE QUICKLY MOVING ACROSS NEW ENGLAND AND
PORTIONS OF UPSTATE NEW YORK. THIS TOO IS EXPECTED TO SLIDE
OFFSHORE TONIGHT LEAVING BEHIND A PTCLOUDY-MOCLEAR SKIES.
BASED ON CURRENT DEWPOINTS...MOS TEMPERATURES LOOK A BIT COOL AND
HAVE FOLLOWED WARMER OVERNIGHT TRENDS WITHIN THE LAV/LAMP
GUIDANCE.
LARGE AREA OF HIGH PRESSURE...CENTERED OVER THE SOUTHEAST
CONUS...WILL BE THE DOMINANT PLAYER FOR THIS NEAR TERM AND INTO
THE SHORT TERM.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
THIS LARGE AREA OF HIGH PRESSURE WILL KEEP THE WEATHER QUIET EAST
OF THE MISSISSIPPI RIVER THROUGH THIS SHORT TERM PERIOD. IN
FACT...RATHER PRONOUNCED WEST-SOUTHWEST FLOW ALONG WITH MILD MID
LEVEL TEMPS WILL RESULT IN TEMPERATURES CLIMBING TOWARD OR
EXCEEDING 10 DEGREES ABOVE CLIMATOLOGY /IN ADDITION...DOWNSLOPING
MAY ENHANCE THESE TEMPS INTO THE VALLEY LOCATIONS/. THE ONLY
COMPLICATION COULD BE SOME OVERNIGHT SHALLOW BR/FG AND A POTENTIAL
FOR SOME LOW LEVEL STRATUS DEVELOPMENT. IN ADDITION...WITH THE
ONGOING WARM ADVECTION...SOME HIGH AND MID LEVEL CLOUD COVER MAY
MOVE ACROSS THE SKY THOUGH THIS PERIOD. EITHER WAY...THE WEATHER
SHOULD HAVE MINIMAL IMPACT TO HOLIDAY WEEKEND TRAVELS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ACTIVE WEATHER PATTERN EXPECTED THROUGH THE LONG TERM...BUT MODEL
GUIDANCE HAS DIFFERING SOLUTIONS...SO CONFIDENCE IS LOW. WENT WITH
HPC GUIDANCE.
SFC LOW APPROACHING FROM THE GREAT LAKES REGION SUNDAY MORNING. 12Z
GFS...ECMWF AND GFSENSEMBLE MEMBERS HAVE NOT AGREED UPON A
TRACK...SPEED...OR QPF AMOUNTS. ECMWF HAS THE MORE PROGRESSIVE AND
NORTHERLY TRACK OF SFC LOW...WITH THE COLD FRONT AND PRECIP
ASSOCIATED WITH THE LOW MOVING THROUGH THE FA LATE SUNDAY THROUGH
LATE MONDAY...WITH QPF AMOUNTS AROUND HALF AN INCH OR LESS.
ASSOCIATED UPPER LEVEL POSITIVELY TILTED TROUGH REMAINS OPEN IN
ECMWF.
MEANWHILE...GFS DEVELOPS A CLOSE LOW WITHIN THE UPPER LEVEL TROUGH.
AS THIS TROUGH APPEARS TO HAVE A NEUTRAL TILT...GFS KEEPS IT SLOW
MOVING OVER THE GREAT LAKES REGION...WHERE THE UPPER LEVEL LOW
PRESSURE CENTER REFORMS FURTHER NORTH SUNDAY NIGHT. THE TROUGH
BECOMES NEGATIVELY TILTED BEFORE A PIECE OF SOUTHERLY ENERGY BREAKS
OFF...TRAVELING TOWARDS THE OBX AHEAD OF THE MAIN TROUGH...BY
TUESDAY NIGHT. QPF AMOUNTS UP TO 2 INCHES WITH THE GFS.
CHANCE FOR PRECIP POSSIBLE THROUGH TUESDAY NIGHT/WEDNESDAY WITH GFS
ENSEMBLE MEMBERS SLOWLY MOVE SFC LOW NORTHWARD TOWARDS JAMES BAY.
ALL GUIDANCE SHOW HIGH PRESSURE BUILDING IN JUST SOUTH OF THE
REGION...BUT NO AGREEMENT ON WHEN OR FOR HOW LONG. HPC HAS HIGH
PRESSURE WEDNESDAY INTO THURSDAY.
TEMPS ABOUT 10 DEGREES ABOVE NORMAL TO START THE PERIOD...TRENDING
COOLER TO ABOUT NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL CONTINUE TO RIDGE IN FROM THE MID ATLANTIC
REGION OVERNIGHT INTO TOMORROW.
VFR CONDITIONS WILL PREVAIL FROM KALB SOUTH OVERNIGHT...BUT SOME
IFR/MVFR MIST/STRATUS WILL LIKELY BE AN ISSUE AT KGFL OVERNIGHT.
THE SKIES HAVE CLEARED...WITH LIGHT TO CALM WINDS AND SOME PATCHY
MVFR MIST HAS ALREADY DEVELOPED AT KGFL. WE WILL CONTINUE THIS
TREND OF MVFR/IFR MIST...AND POSSIBLY SOME MVFR STRATUS PRIOR TO
12Z/FRI.
THE SKIES WILL BE MOSTLY CLEAR IN THE LATE MORNING THROUGH THE
AFTERNOON WITH VFR CONDITIONS PREVAILING DUE TO THE STRONG
SUBSIDENCE FROM THE ANTICYCLONE.
THE WINDS WILL BE LIGHT TO CALM OVERNIGHT. THEY WILL INCREASE FROM
THE S/SW AT 5-10 KTS DURING THE LATE MORNING AND AFTERNOON.
OUTLOOK...
FRIDAY NIGHT-SAT NIGHT...VFR. NO SIG WX.
SUN...MAINLY VFR. INCREASING CLDS. CHC PM -SHRAS.
SUN NIGHT-TUE...MVFR/IFR WITH CHC -SHRAS.
&&
.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH MOST OF THE LONG HOLIDAY WEEKEND
AS HIGH PRESSURE DOMINATES. OUR NEXT CHANCES FOR WET WEATHER WILL
RETURN LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS A LOW PRESSURE
SYSTEM APPROACHES AND MOVES ACROSS THE REGION. THERE IS MUCH
UNCERTAINTY WITH REGARDS TO THE SYSTEM AS THERE IS A LARGE SPREAD
IN THE MODEL GUIDANCE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
2011 HAS MOVED UP INTO FIFTH PLACE FOR WETTEST YEARS ON RECORD
FOR ALBANY NEW YORK.
WETTEST YEARS - ALBANY NY - SINCE 1820
1) 55.78 INCHES 1871
2) 55.81 INCHES 1870
3) 51.83 INCHES 1850
4) 49.80 INCHES 1827
5) 49.75 INCHES THROUGH NOVEMBER 23ND
6) 49.37 INCHES 1878
7) 48.35 INCHES 1843
8) 48.22 INCHES 1848
9) 47.79 INCHES 2008
10) 47.72 INCHES 2005
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...BGM/WASULA
SHORT TERM...BGM
LONG TERM...KGM
AVIATION...WASULA
HYDROLOGY...BGM
CLIMATE...IAA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
918 AM EST WED NOV 23 2011
.SYNOPSIS...
INTENSIFYING LOW PRESSURE MOVING EASTWARD THROUGH PENNSYLVANIA EARLY
THIS MORNING...WITH A WARM FRONT EXTENDING EASTWARD INTO OUR
AREA...WILL PASS THROUGH OUR REGION LATER THIS MORNING AND EARLY
THIS AFTERNOON. THE TRAILING COLD FRONT WILL MOVE SOUTHEAST OF OUR
AREA BY EVENING. HIGH PRESSURE WILL BUILD INTO THE MID ATLANTIC
STATES THURSDAY AND FRIDAY AND SAG SOUTHWARD INTO THE CAROLINAS
THIS WEEKEND. A COLD FRONT MAY MOVE EASTWARD THROUGH OUR AREA
SUNDAY NIGHT INTO EARLY MONDAY. LOW PRESSURE DEVELOPING OVER THE
GREAT LAKES AND OHIO VALLEY AND EXTENDING INTO THE SOUTHEASTERN
STATES BY TUESDAY MAY AFFECT OUR AREA INTO THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FIRST SHOT OR PRECIPITATION HAS MOVED OUT...WITH THE NEXT SHOT
MOVING ACROSS AREAS NORTHWEST OF PHILADELPHIA. ALSO SEEING A LINE OF
SHOWERS WITH A WIND SHIFT MOVING INTO THE LEHIGH VALLEY. FINALLY...A
WARM FRONT CUTS ACROSS NORTHEAST MARYLAND...NORTHERN DELAWARE AND
SOUTHERN NEW JERSEY. NORTH OF THE FRONT...THE AREA IS MOSTLY RAIN
FREE AND WINDS HAVE SHIFTED TO THE SOUTH. THIS IS ALLOWING HIGHER
DEW POINTS TO ADVECT INTO THAT AREA.
THE MAIN WEATHER PROBLEM FOR TODAY WILL BE TIED TO A SURFACE COLD
FRONT. AHEAD OF THE FRONT...MOISTURE RICH AIR IS RIDING NORTHEAST ON
A 55 KNOT LOW LEVEL JET. FOR THE MOST PART...THE AIRMASS IS STABLE
EVEN SOUTH OF THE WARM FRONT. THERE IS INSTABILITY ACROSS SOUTHEAST
VIRGINIA...AND THIS COULD BE ADVECTED INTO SOUTHERN AREAS THIS
MORNING.
THE BEST CHANCE OF THUNDER WILL BE TIED TO THE INSTABILITY IN
SOUTHEAST VIRGINIA. THE HRRR ADVECTS THIS INSTABILITY INTO NORTHEAST
MARYLAND...DELAWARE AND SOUTHERN NEW JERSEY THROUGH ABOUT 1500 UTC.
BASED ON THIS...WILL HOLD ONTO THE MENTION OF THUNDER IN THESE
AREAS. THE BULK SHEAR VALUES WILL BE HIGH...BUT FOR NOW WILL HOLD
OFF ON ENHANCED WORDING FOR GUSTY WINDS.
THE HEAVIEST RAIN WILL FALL ACROSS EASTERN PENNSYLVANIA AND NORTHERN
NE JERSEY THIS MORNING. AN ADDITIONAL ONE TO ONE AND ONE-HALF INCHES
OF RAIN COULD FALL IN THE AIRMASS JUST AHEAD OF THE FRONT. THE
ADDITIONAL RAIN SHOULD RESULT IN FLOODING. MORE ON THE FLOODING
ISSUES IS INCLUDED IN THE HYDROLOGY SECTION BELOW.
AFTER THE FRONT PASSES...THE MAIN MOISTURE SHOULD BE SCOURED BY THE
FRONT AND EXITING LOW LEVEL JET. HOWEVER...THE MID LEVEL LONG WAVE
TROUGH STILL REMAINS TO THE WEST. WHILE WINDS SHIFTING TO THE WEST
BEHIND THE FRONT SHOULD DRY OUT OUT THE LOWER LEVELS...COLD MID
LEVEL TEMPERATURES AND SYNOPTIC SCALE LIFT AHEAD OF THE LONG WAVE
TROUGH COULD RESULT IN SHOWERS THIS AFTERNOON.
DESPITE THE LOW LEVEL DRYING BEHIND THE FRONT...ANY MEANINGFUL
CLEARING WILL HAVE TO WAIT UNTIL THE PASSAGE OF THE MID LEVEL
TROUGH. WITH THIS IN MIND...WILL REMAIN PESSIMISTIC WITH REGARD TO
SKY COVER FOR ALL AREAS. HIGHS SHOULD OCCUR BEFORE THE FRONT PASSES
THIS MORNING. TEMPERATURES ARE IN THE MID 60S ACROSS MUCH OF EASTERN
VIRGINIA...AND THIS SHOULD ADVECT INTO SOUTHERN AREAS.
THIS IS MORE OR LESS IN LINE WITH MOS VALUES...AND ARE ACCEPTED.
ELSEWHERE...HIGHS WERE MAINLY BASED ON THE MOS BLEND. IT IS POSSIBLE
THAT PORTIONS OF THE LEHIGH VALLEY AND SOUTHERN POCONOS MAY HAVE
TEMPERATURES BECOME STEADY OR SLOWLY FALL BEHIND THE MAIN FRONT
LATER THIS MORNING. THIS WAS ACCOUNTED FOR IN THE HOURLY TEMPERATURE
FORECAST.
FINALLY...THE GRADIENT STARTS TO TIGHTEN LATE THIS AFTERNOON AS
SURFACE LOW PRESSURE DEEPENS TO THE NORTHEAST. THE GRADIENT SUPPORTS
GUSTY WINDS IN JUST ABOUT ALL AREAS FROM MID AFTERNOON ON. MODEL
SOUNDINGS SUGGEST GUSTS TO 35 MPH ARE POSSIBLE TOWARD DARK...AS
WINDS SHIFT TO THE NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE BIGGEST ISSUE THIS EVENING WILL BE THE WIND. AS THE SURFACE LOW
DEEPENS TO THE NORTHEAST THIS EVENING...THE GRADIENT TIGHTENS
CONSIDERABLY. THE GRADIENT ITSELF WOULD SUPPORT WIND GUSTS TO 25 MPH
FOR JUST ABOUT ALL AREAS. HOWEVER...MODEL SOUNDINGS NEAR THE COAST
SUGGEST A THREE HOUR WIND CENTERED AROUND 0000 UTC WHEN 43 KNOTS OF
WIND MAY BE AVAILABLE AT THE TOP OF THE MIXED LAYER.
THIS IS ABOUT THE TIME OF THE BEST COLD AIR ADVECTION...WHEN
PRESSURE RISES OF 6 TO 7 MB IN 3 HOURS ARE FORECAST. THIS COULD
RESULT IN A SHORT PERIOD OF NEAR WIND ADVISORY TYPE WINDS...
ESPECIALLY FOR PORTION OF MARYLAND...DELAWARE AND SOUTHERN NEW
JERSEY. RIGHT NOW...THE CONFIDENCE DOES NOT EXIST FOR THE ISSUANCE
OF A WIND ADVISORY.
THE MID LEVEL LONG WAVE TROUGH SHOULD EXIT THE COAST DURING THE
EVENING (PROBABLY BEFORE 0300 UTC THURSDAY). WITH COLD MID LEVEL
TEMPERATURES AND SOME SYNOPTIC SCALE LIFT WITH THE TROUGH ITSELF...A
MENTION OF SHOWERS WAS LEFT IN PLACE FOR THE EVENING HOURS.
IN THE WAKE OF THE TROUGH...SKIES SHOULD CLEAR FAIRLY QUICKLY. THE
BEST GRADIENT OCCURS DURING THE EVENING...AND WEAKENS DURING THE
LATE PART OF THE OVERNIGHT. THE WEAKENING GRADIENT AND COOLING OF
THE LOWEST LEVELS COULD ALLOW SOME PROTECTED AREAS TO DECOUPLE LATER
TONIGHT. THIS COULD RESULT IN SOME OF THESE LOCATIONS DROPPING BELOW
MOS VALUES...BUT OVERALL...WITH A MIXED ENVIRONMENT MOST OF THE
NIGHT...LOWS WERE BASED ON THE MOS BLEND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE MODELS ARE A SOMEWHAT CONFIDENT ON INDICATING A COLD FRONT
MOVING INTO OR THROUGH OUR AREA SUNDAY NIGHT INTO EARLY MONDAY. IT
SEEMS TO BE AN ANAFRONT...SO HIGH CHANCE TO LOW LIKELY
PRECIPITATION CHANCES WERE USED SUNDAY NIGHT MAINLY WEST AND
CENTRAL. THEN...LOW PRESSURE FORMING SURFACE AND ALOFT ARE HANDLED
SLIGHTLY DIFFERENTLY BY THE 00Z GFS AND 00Z ECMWF...WITH THE
LATTER A LITTLE FURTHER SOUTH AND EAST WITH THE SURFACE LOW AS
COMPARED WITH THE GFS. HOWEVER...THE GENERAL EVOLUTION OF THE
AMPLIFYING UPPER PATTERN ON EACH IS SIMILAR. BUT, THIS MEANS A
GOOD DEAL OF UNCERTAINTY IN LOCATION AND TIMING OF FEATURES.
SO...AFTER SUNDAY NIGHT...A RATHER BROAD BRUSH WAS USED WITH HIGH
CHANCE PROBABILITIES GENERALLY EMPLOYED. AT THIS POINT, IT LOOKS
LIKE TUESDAY AND WEDNESDAY WILL FEATURE AT LEAST SOME
PRECIPITATION, AND IT COULD BE A SIGNIFICANT EVENT.
TEMPERATURES IN THE GRIDS WERE NOT TOO DIFFERENT FROM HPC
GUIDANCE PRODUCTS.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CONDITIONS CONTINUE EARLY THIS MORNING ACROSS THE REGION.
THE FIRST SHOT OF STEADIER RANI HAS EXITED THE AREA...WITH SCATTERED
SHOWERS IN BETWEEN. THE NEXT SHOT OF RAIN IS WAITING ACROSS WESTERN
MARYLAND AND CENTRAL PENNSYLVANIA. AS THIS SHOT OF RAIN MOVES INTO
THE AREA...IFR CEILINGS ARE EXPECTED IN ALL AREAS.
LOW LEVEL WIND SHEAR IS NOW PRESENT IN THE KDIX VWP AND AMDAR
SOUNDINGS OUT OF KPHL...WITH 45 KNOTS AT 2000 FEET. THE GREATEST
EFFECTS OF THE OW LEVEL WIND SHEAR ARE BEING FELT FROM KPHL SOUTH
AND WEST. THIS IS IN RESPONSE TO A LOW LEVEL JET APPROACHING FROM
THE SOUTH SOUTHWEST. THE LOW LEVEL JET IS PUSHING THE NEXT SHOT OF
PRECIPITATION...AND LOW LEVEL WIND SHEAR IS EXPECTED THROUGH A COLD
FRONTAL PASSAGE LATE THIS MORNING.
A WEAK COLD FRONT WILL CROSS THE REGION BETWEEN 1100 UTC AND 1400
UTC. THIS FRONT WILL ONLY SERVE AS A WIND SHIFT...WITH LITTLE NI THE
WAY OF DRYING BEHIND. CEILINGS WILL REMAIN IFR THROUGH THE INITIAL
COLD FRONTAL PASSAGE. A MORE SIGNIFICANT FRONT WILL CROSS THE REGION
FROM WEST TO EAST BETWEEN 1600 UTC WEST AND 1900 UTC EAST. DRYING IN
THE LOWER LEVELS SHOULD HELP CEILINGS JUMP TO MVFR...WITH A FEW
SHOWERS POSSIBLE WITH THE FRONT. LOOKS FOR CEILINGS TO FINALLY GET
TO VFR BETWEEN 1900 UTC AND 2200 UTC...FROM WEST TO EAST.
WINDS WILL SHIFT TO THE WEST NORTHWEST BEHIND THE SECOND FRONT...AND
AS THE SURFACE GRADIENT INCREASES...SHOULD GUST TO 25 KNOTS FOR THE
MUCH OF THE REST OF THE AFTERNOON. AS LOW PRESSURE DEEPENS TO THE
NORTHEAST LATE THIS AFTERNOON AND TONIGHT...WINDS WILL SHIFT TO THE
NORTH. MODEL SOUNDINGS SUGGEST GUSTS BETWEEN 29 AND 35 KNOTS ARE
POSSIBLE FOR A TIME BETWEEN 0100 UTC AND 0600 UTC...WITH THE HIGHEST
GUSTS SOUTH AND EAST OF KPHL.
ALL TERMINALS SHOULD BE VFR BY 0000 UTC...AND SKIES WILL CLEAR
DURING THE EVENING HOURS.
OUTLOOK...
VFR CONDITIONS WILL OCCUR THURSDAY AND INTO MOST OF THE WEEKEND...
AS HIGH PRESSURE BUILDING INTO OUR AREA WILL LIKELY HANG ON INTO
SUNDAY. THURSDAY MAY START WITH SOMEWHAT GUSTY WINDS IN THE WAKE
OF WEDNESDAYS FRONT, AS THE GRADIENT IS STILL A LITTLE STRONG.
HOWEVER...ANY GUSTY MORNING WINDS SHOULD SETTLE DOWN IN THE
AFTERNOON. A FRONT MOVING IN FROM THE WEST MAY BRING SOME LOWER
CONDITIONS SUNDAY NIGHT INTO MONDAY. THEN...THE WEATHER BECOMES
MORE COMPLICATED AND UNCERTAIN, AS EXTENSIVE LOW PRESSURE WELL TO
OUR WEST OVER THE GREAT LAKES AND OHIO VALLEY AND INTO THE
SOUTHEAST IS LIKELY TO BE A WEATHER-MAKER FOR OUR AREA IN THE
EARLY AND MID PORTION OF NEXT WEEK. AVIATION CONDITIONS COULD BE
LOW THROUGH THIS PERIOD.
&&
.MARINE...
THE SURFACE WARM FRONT EXTENDS ACROSS NORTHERN DELAWARE AND THE
SOUTHERN THIRD OF NEW JERSEY EARLY THIS MORNING. NORTH OF THE
FRONT...EAST TO NORTHEAST WINDS REMAIN CLOSE TO SMALL CRAFT
LEVELS...WITH THE HIGHEST WINDS CLOSE TO SANDY HOOK. THE EASTERLY
FETCH HAS ALSO RESULTED IN SMALL CRAFT SEAS.
SOUTH OF THE FRONT...WINDS HAVE SHIFTED TO THE SOUTH...AND REMAIN
JUST BELOW SMALL CRAFT LEVELS. THE DEPTH OF THE MIXED LAYER PROBABLY
DOES NOT ALLOW THE MOMENTUM FROM THE PASSING LOW LEVEL JET TO MIX TO
THE SURFACE...SO WINDS PROBABLY STAY NEAR SMALL CRAFT LEVELS AHEAD
OF AN APPROACHING COLD FRONT. SEAS HERE ARE ALSO ABOVE 5 FEET...AS A
RESULT OF THE PREVIOUS EASTERLY SWELL..
THE WARM FRONT MAY NOT CLEAR THE ENTIRE COAST THIS MORNING BEFORE
THE COLD CROSSES. WINDS SHOULD REMAIN NEAR SMALL CRAFT LEVELS...BUT
AS MENTIONED EARLIER...THE MOMENTUM AHEAD OF THE FRONT PROBABLY DOES
NOT ALLOW ENOUGH MIXING FOR GALE FORCE WINDS FROM THE SOUTH. AFTER
THE FRONT PASSES...MODEL SOUNDINGS A PERIOD OF WEST WINDS WHICH MAY
NOT PRODUCE SMALL CRAFT WINDS IN ALL AREAS. HOWEVER...SEAS WILL
REMAIN NEAR 6 FEET ON THE OCEAN...AND PERHAPS 5 FEET ON THE LOWER
DELAWARE BAY.
AS LOW PRESSURE DEEPENS ON ITS WAY SOUTH OF NOVA SCOTIA THIS
EVENING...THE PRESSURE GRADIENT TIGHTENS CONSIDERABLY. THE GRADIENT
ITSELF IS BORDERLINE FOR GALES...BUT MODEL SOUNDINGS SHOW THE DEPTH
OF THE MIXED LAYER IN THE BEST COLD AIR ADVECTION INCREASING TO
ALLOW ACCESS TO 35 TO 40 KNOTS OF WIND. THE SOUTHERN OCEAN WATERS
AND THE LOWER DELAWARE BAY HAVE THE BEST CHANCE OF SEEING WIND GUSTS
NEAR 40 KNOTS DURING A TIME WINDOW OF 0100 UTC TO 0600 UTC THURSDAY.
FURTHER NORTH...THE GRADIENT IS ABOUT AS STRONG...BUT MODEL
SOUNDINGS ARE LESS BULLISH WITH THE MIXING. BOTTOM LINE...THE GALE
WARNING REMAINS IN PLACE...WITH THE STRONGEST WINDS ACROSS SOUTHERN
AREAS. THE GRADIENT STARTS TO RELAX TOWARD 0900 UTC...AND ALL WATERS
SHOULD BE BELOW GALE FORCE WINDS AT THAT TIME.
OUTLOOK...
CONDITIONS ARE EXPECTED TO DROP TO SMALL CRAFT ADVISORY LEVELS BY
THURSDAY MORNING...AND WINDS AND WAVES WILL SUBSIDE FURTHER THURSDAY
MORNING AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST.
THEN...SUB-ADVISORY CONDITIONS ARE FORECAST THURSDAY NIGHT INTO
SUNDAY. A FRONT MOVING IN FROM THE WEST SUNDAY NIGHT COULD PRECEDE
A PERIOD OF UNSETTLED WEATHER EARLY NEXT WEEK.
&&
.HYDROLOGY...
THE SECOND SLUG OF MOISTURE IS MOVING NORTHEAST WITH THE LOW LEVEL
JET...AND THE HEAVIEST RAIN HAS MOVED OUT OF THE WATCH AREA. SINCE
MOST PLACES THAT HAVE A THREAT ARE IN WARNINGS NOW...THE FLASH
FLOOD WATCH HAS BEEN CANCELLED. THERE COULD BE SOME MORE RIVER
FORECAST POINT WARNINGS...BUT THESE WOULD NOT BE COVERED BY A
FLASH FLOOD WARNING.
&&
.TIDES/COASTAL FLOODING...
SOME LOCALIZED MINOR TIDAL FLOODING WAS REPORTED THIS MORNING AT
THE TIME OF HIGH TIDE ALONG THE NJ/DE OCEAN FRONT, ON THE BACK
BAYS, AND ON DELAWARE BAY. HIGH TIDE HAS PASSED, WATER LEVELS
ARE NOW ON THE WAY DOWN, AND THE ADVISORY HAS EXPIRED.
THE COASTAL FLOOD ADVISORY CONTINUES FOR THE TIDAL PORTION OF
THE DELAWARE RIVER. HIGH TIDE WORKS ITS WAY UP THE TIDAL DELAWARE
RIVER AND ITS TIDAL TRIBUTARIES BETWEEN ABOUT 800 AM AND 12:30 PM.
THE LATE AFTERNOON AND EVENING TIDE IS ABOUT THREE-QUARTERS TO ONE
FOOT LOWER THAN THIS MORNING. WINDS SHOULD SHIFT TO THE NORTH...AND
INCREASE. THIS COULD RESULT IN THE DEVELOPMENT OF AN EKMAN SPIRAL
MASS TRANSPORT (BUT IT MAY NOT BE IN PLACE LONG ENOUGH TO MATTER)
TOWARD THE BEACH. RIGHT NOW...THIS TIDE DOES NOT APPEAR TO PRESENT A
PROBLEM.
THE NEXT TIDE OF INTEREST WOULD BE THE EARLY MORNING HIGH TIDE CYCLE
THURSDAY. DESPITE THE OFFSHORE WIND...THE MDL EXTRATROPICAL SURGE
MODEL IS SUGGESTING THAT THE OCEAN FRONT WILL SEE MINOR TIDAL
FLOODING. THIS IS MORE THAN 24 HOURS OUT...WITH PLENTY OF TIME TO
MONITOR TRENDS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ070-071.
NJ...COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NJZ016>019.
DE...COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
DEZ001.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-
431-450>455.
GALE WARNING FROM 6 PM THIS EVENING TO 4 AM EST THURSDAY FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...
AVIATION...HAYES
MARINE...HAYES
HYDROLOGY...HAYES
TIDES/COASTAL FLOODING...HAYES/RPW
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
643 AM EST WED NOV 23 2011
.SYNOPSIS...
INTENSIFYING LOW PRESSURE MOVING EASTWARD THROUGH PENNSYLVANIA EARLY
THIS MORNING...WITH A WARM FRONT EXTENDING EASTWARD INTO OUR
AREA...WILL PASS THROUGH OUR REGION LATER THIS MORNING AND EARLY
THIS AFTERNOON. THE TRAILING COLD FRONT WILL MOVE SOUTHEAST OF OUR
AREA BY EVENING. HIGH PRESSURE WILL BUILD INTO THE MID ATLANTIC
STATES THURSDAY AND FRIDAY AND SAG SOUTHWARD INTO THE CAROLINAS
THIS WEEKEND. A COLD FRONT MAY MOVE EASTWARD THROUGH OUR AREA
SUNDAY NIGHT INTO EARLY MONDAY. LOW PRESSURE DEVELOPING OVER THE
GREAT LAKES AND OHIO VALLEY AND EXTENDING INTO THE SOUTHEASTERN
STATES BY TUESDAY MAY AFFECT OUR AREA INTO THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FIRST SHOT OR PRECIPITATION HAS MOVED OUT...WITH THE NEXT SHOT
MOVING ACROSS AREAS NORTHWEST OF PHILADELPHIA. ALSO SEEING A LINE OF
SHOWERS WITH A WIND SHIFT MOVING INTO THE LEHIGH VALLEY. FINALLY...A
WARM FRONT CUTS ACROSS NORTHEAST MARYLAND...NORTHERN DELAWARE AND
SOUTHERN NEW JERSEY. NORTH OF THE FRONT...THE AREA IS MOSTLY RAIN
FREE AND WINDS HAVE SHIFTED TO THE SOUTH. THIS IS ALLOWING HIGHER
DEW POINTS TO ADVECT INTO THAT AREA.
THE MAIN WEATHER PROBLEM FOR TODAY WILL BE TIED TO A SURFACE COLD
FRONT. AHEAD OF THE FRONT...MOISTURE RICH AIR IS RIDING NORTHEAST ON
A 55 KNOT LOW LEVEL JET. FOR THE MOST PART...THE AIRMASS IS STABLE
EVEN SOUTH OF THE WARM FRONT. THERE IS INSTABILITY ACROSS SOUTHEAST
VIRGINIA...AND THIS COULD BE ADVECTED INTO SOUTHERN AREAS THIS
MORNING.
THE BEST CHANCE OF THUNDER WILL BE TIED TO THE INSTABILITY IN
SOUTHEAST VIRGINIA. THE HRRR ADVECTS THIS INSTABILITY INTO NORTHEAST
MARYLAND...DELAWARE AND SOUTHERN NEW JERSEY THROUGH ABOUT 1500 UTC.
BASED ON THIS...WILL HOLD ONTO THE MENTION OF THUNDER IN THESE
AREAS. THE BULK SHEAR VALUES WILL BE HIGH...BUT FOR NOW WILL HOLD
OFF ON ENHANCED WORDING FOR GUSTY WINDS.
THE HEAVIEST RAIN WILL FALL ACROSS EASTERN PENNSYLVANIA AND NORTHERN
NE JERSEY THIS MORNING. AN ADDITIONAL ONE TO ONE AND ONE-HALF INCHES
OF RAIN COULD FALL IN THE AIRMASS JUST AHEAD OF THE FRONT. THE
ADDITIONAL RAIN SHOULD RESULT IN FLOODING. MORE ON THE FLOODING
ISSUES IS INCLUDED IN THE HYDROLOGY SECTION BELOW.
AFTER THE FRONT PASSES...THE MAIN MOISTURE SHOULD BE SCOURED BY THE
FRONT AND EXITING LOW LEVEL JET. HOWEVER...THE MID LEVEL LONG WAVE
TROUGH STILL REMAINS TO THE WEST. WHILE WINDS SHIFTING TO THE WEST
BEHIND THE FRONT SHOULD DRY OUT OUT THE LOWER LEVELS...COLD MID
LEVEL TEMPERATURES AND SYNOPTIC SCALE LIFT AHEAD OF THE LONG WAVE
TROUGH COULD RESULT IN SHOWERS THIS AFTERNOON.
DESPITE THE LOW LEVEL DRYING BEHIND THE FRONT...ANY MEANINGFUL
CLEARING WILL HAVE TO WAIT UNTIL THE PASSAGE OF THE MID LEVEL
TROUGH. WITH THIS IN MIND...WILL REMAIN PESSIMISTIC WITH REGARD TO
SKY COVER FOR ALL AREAS. HIGHS SHOULD OCCUR BEFORE THE FRONT PASSES
THIS MORNING. TEMPERATURES ARE IN THE MID 60S ACROSS MUCH OF EASTERN
VIRGINIA...AND THIS SHOULD ADVECT INTO SOUTHERN AREAS.
THIS IS MORE OR LESS IN LINE WITH MOS VALUES...AND ARE ACCEPTED.
ELSEWHERE...HIGHS WERE MAINLY BASED ON THE MOS BLEND. IT IS POSSIBLE
THAT PORTIONS OF THE LEHIGH VALLEY AND SOUTHERN POCONOS MAY HAVE
TEMPERATURES BECOME STEADY OR SLOWLY FALL BEHIND THE MAIN FRONT
LATER THIS MORNING. THIS WAS ACCOUNTED FOR IN THE HOURLY TEMPERATURE
FORECAST.
FINALLY...THE GRADIENT STARTS TO TIGHTEN LATE THIS AFTERNOON AS
SURFACE LOW PRESSURE DEEPENS TO THE NORTHEAST. THE GRADIENT SUPPORTS
GUSTY WINDS IN JUST ABOUT ALL AREAS FROM MID AFTERNOON ON. MODEL
SOUNDINGS SUGGEST GUSTS TO 35 MPH ARE POSSIBLE TOWARD DARK...AS
WINDS SHIFT TO THE NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE BIGGEST ISSUE THIS EVENING WILL BE THE WIND. AS THE SURFACE LOW
DEEPENS TO THE NORTHEAST THIS EVENING...THE GRADIENT TIGHTENS
CONSIDERABLY. THE GRADIENT ITSELF WOULD SUPPORT WIND GUSTS TO 25 MPH
FOR JUST ABOUT ALL AREAS. HOWEVER...MODEL SOUNDINGS NEAR THE COAST
SUGGEST A THREE HOUR WIND CENTERED AROUND 0000 UTC WHEN 43 KNOTS OF
WIND MAY BE AVAILABLE AT THE TOP OF THE MIXED LAYER.
THIS IS ABOUT THE TIME OF THE BEST COLD AIR ADVECTION...WHEN
PRESSURE RISES OF 6 TO 7 MB IN 3 HOURS ARE FORECAST. THIS COULD
RESULT IN A SHORT PERIOD OF NEAR WIND ADVISORY TYPE WINDS...
ESPECIALLY FOR PORTION OF MARYLAND...DELAWARE AND SOUTHERN NEW
JERSEY. RIGHT NOW...THE CONFIDENCE DOES NOT EXIST FOR THE ISSUANCE
OF A WIND ADVISORY.
THE MID LEVEL LONG WAVE TROUGH SHOULD EXIT THE COAST DURING THE
EVENING (PROBABLY BEFORE 0300 UTC THURSDAY). WITH COLD MID LEVEL
TEMPERATURES AND SOME SYNOPTIC SCALE LIFT WITH THE TROUGH ITSELF...A
MENTION OF SHOWERS WAS LEFT IN PLACE FOR THE EVENING HOURS.
IN THE WAKE OF THE TROUGH...SKIES SHOULD CLEAR FAIRLY QUICKLY. THE
BEST GRADIENT OCCURS DURING THE EVENING...AND WEAKENS DURING THE
LATE PART OF THE OVERNIGHT. THE WEAKENING GRADIENT AND COOLING OF
THE LOWEST LEVELS COULD ALLOW SOME PROTECTED AREAS TO DECOUPLE LATER
TONIGHT. THIS COULD RESULT IN SOME OF THESE LOCATIONS DROPPING BELOW
MOS VALUES...BUT OVERALL...WITH A MIXED ENVIRONMENT MOST OF THE
NIGHT...LOWS WERE BASED ON THE MOS BLEND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE MODELS ARE A SOMEWHAT CONFIDENT ON INDICATING A COLD FRONT
MOVING INTO OR THROUGH OUR AREA SUNDAY NIGHT INTO EARLY MONDAY. IT
SEEMS TO BE AN ANAFRONT...SO HIGH CHANCE TO LOW LIKELY
PRECIPITATION CHANCES WERE USED SUNDAY NIGHT MAINLY WEST AND
CENTRAL. THEN...LOW PRESSURE FORMING SURFACE AND ALOFT ARE HANDLED
SLIGHTLY DIFFERENTLY BY THE 00Z GFS AND 00Z ECMWF...WITH THE
LATTER A LITTLE FURTHER SOUTH AND EAST WITH THE SURFACE LOW AS
COMPARED WITH THE GFS. HOWEVER...THE GENERAL EVOLUTION OF THE
AMPLIFYING UPPER PATTERN ON EACH IS SIMILAR. BUT, THIS MEANS A
GOOD DEAL OF UNCERTAINTY IN LOCATION AND TIMING OF FEATURES.
SO...AFTER SUNDAY NIGHT...A RATHER BROAD BRUSH WAS USED WITH HIGH
CHANCE PROBABILITIES GENERALLY EMPLOYED. AT THIS POINT, IT LOOKS
LIKE TUESDAY AND WEDNESDAY WILL FEATURE AT LEAST SOME
PRECIPITATION, AND IT COULD BE A SIGNIFICANT EVENT.
TEMPERATURES IN THE GRIDS WERE NOT TOO DIFFERENT FROM HPC
GUIDANCE PRODUCTS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CONDITIONS CONTINUE EARLY THIS MORNING ACROSS THE REGION.
THE FIRST SHOT OF STEADIER RANI HAS EXITED THE AREA...WITH SCATTERED
SHOWERS IN BETWEEN. THE NEXT SHOT OF RAIN IS WAITING ACROSS WESTERN
MARYLAND AND CENTRAL PENNSYLVANIA. AS THIS SHOT OF RAIN MOVES INTO
THE AREA...IFR CEILINGS ARE EXPECTED IN ALL AREAS.
LOW LEVEL WIND SHEAR IS NOW PRESENT IN THE KDIX VWP AND AMDAR
SOUNDINGS OUT OF KPHL...WITH 45 KNOTS AT 2000 FEET. THE GREATEST
EFFECTS OF THE OW LEVEL WIND SHEAR ARE BEING FELT FROM KPHL SOUTH
AND WEST. THIS IS IN RESPONSE TO A LOW LEVEL JET APPROACHING FROM
THE SOUTH SOUTHWEST. THE LOW LEVEL JET IS PUSHING THE NEXT SHOT OF
PRECIPITATION...AND LOW LEVEL WIND SHEAR IS EXPECTED THROUGH A COLD
FRONTAL PASSAGE LATE THIS MORNING.
A WEAK COLD FRONT WILL CROSS THE REGION BETWEEN 1100 UTC AND 1400
UTC. THIS FRONT WILL ONLY SERVE AS A WIND SHIFT...WITH LITTLE NI THE
WAY OF DRYING BEHIND. CEILINGS WILL REMAIN IFR THROUGH THE INITIAL
COLD FRONTAL PASSAGE. A MORE SIGNIFICANT FRONT WILL CROSS THE REGION
FROM WEST TO EAST BETWEEN 1600 UTC WEST AND 1900 UTC EAST. DRYING IN
THE LOWER LEVELS SHOULD HELP CEILINGS JUMP TO MVFR...WITH A FEW
SHOWERS POSSIBLE WITH THE FRONT. LOOKS FOR CEILINGS TO FINALLY GET
TO VFR BETWEEN 1900 UTC AND 2200 UTC...FROM WEST TO EAST.
WINDS WILL SHIFT TO THE WEST NORTHWEST BEHIND THE SECOND FRONT...AND
AS THE SURFACE GRADIENT INCREASES...SHOULD GUST TO 25 KNOTS FOR THE
MUCH OF THE REST OF THE AFTERNOON. AS LOW PRESSURE DEEPENS TO THE
NORTHEAST LATE THIS AFTERNOON AND TONIGHT...WINDS WILL SHIFT TO THE
NORTH. MODEL SOUNDINGS SUGGEST GUSTS BETWEEN 29 AND 35 KNOTS ARE
POSSIBLE FOR A TIME BETWEEN 0100 UTC AND 0600 UTC...WITH THE HIGHEST
GUSTS SOUTH AND EAST OF KPHL.
ALL TERMINALS SHOULD BE VFR BY 0000 UTC...AND SKIES WILL CLEAR
DURING THE EVENING HOURS.
OUTLOOK...
VFR CONDITIONS WILL OCCUR THURSDAY AND INTO MOST OF THE WEEKEND...
AS HIGH PRESSURE BUILDING INTO OUR AREA WILL LIKELY HANG ON INTO
SUNDAY. THURSDAY MAY START WITH SOMEWHAT GUSTY WINDS IN THE WAKE
OF WEDNESDAYS FRONT, AS THE GRADIENT IS STILL A LITTLE STRONG.
HOWEVER...ANY GUSTY MORNING WINDS SHOULD SETTLE DOWN IN THE
AFTERNOON. A FRONT MOVING IN FROM THE WEST MAY BRING SOME LOWER
CONDITIONS SUNDAY NIGHT INTO MONDAY. THEN...THE WEATHER BECOMES
MORE COMPLICATED AND UNCERTAIN, AS EXTENSIVE LOW PRESSURE WELL TO
OUR WEST OVER THE GREAT LAKES AND OHIO VALLEY AND INTO THE
SOUTHEAST IS LIKELY TO BE A WEATHER-MAKER FOR OUR AREA IN THE
EARLY AND MID PORTION OF NEXT WEEK. AVIATION CONDITIONS COULD BE
LOW THROUGH THIS PERIOD.
&&
.MARINE...
THE SURFACE WARM FRONT EXTENDS ACROSS NORTHERN DELAWARE AND THE
SOUTHERN THIRD OF NEW JERSEY EARLY THIS MORNING. NORTH OF THE
FRONT...EAST TO NORTHEAST WINDS REMAIN CLOSE TO SMALL CRAFT
LEVELS...WITH THE HIGHEST WINDS CLOSE TO SANDY HOOK. THE EASTERLY
FETCH HAS ALSO RESULTED IN SMALL CRAFT SEAS.
SOUTH OF THE FRONT...WINDS HAVE SHIFTED TO THE SOUTH...AND REMAIN
JUST BELOW SMALL CRAFT LEVELS. THE DEPTH OF THE MIXED LAYER PROBABLY
DOES NOT ALLOW THE MOMENTUM FROM THE PASSING LOW LEVEL JET TO MIX TO
THE SURFACE...SO WINDS PROBABLY STAY NEAR SMALL CRAFT LEVELS AHEAD
OF AN APPROACHING COLD FRONT. SEAS HERE ARE ALSO ABOVE 5 FEET...AS A
RESULT OF THE PREVIOUS EASTERLY SWELL..
THE WARM FRONT MAY NOT CLEAR THE ENTIRE COAST THIS MORNING BEFORE
THE COLD CROSSES. WINDS SHOULD REMAIN NEAR SMALL CRAFT LEVELS...BUT
AS MENTIONED EARLIER...THE MOMENTUM AHEAD OF THE FRONT PROBABLY DOES
NOT ALLOW ENOUGH MIXING FOR GALE FORCE WINDS FROM THE SOUTH. AFTER
THE FRONT PASSES...MODEL SOUNDINGS A PERIOD OF WEST WINDS WHICH MAY
NOT PRODUCE SMALL CRAFT WINDS IN ALL AREAS. HOWEVER...SEAS WILL
REMAIN NEAR 6 FEET ON THE OCEAN...AND PERHAPS 5 FEET ON THE LOWER
DELAWARE BAY.
AS LOW PRESSURE DEEPENS ON ITS WAY SOUTH OF NOVA SCOTIA THIS
EVENING...THE PRESSURE GRADIENT TIGHTENS CONSIDERABLY. THE GRADIENT
ITSELF IS BORDERLINE FOR GALES...BUT MODEL SOUNDINGS SHOW THE DEPTH
OF THE MIXED LAYER IN THE BEST COLD AIR ADVECTION INCREASING TO
ALLOW ACCESS TO 35 TO 40 KNOTS OF WIND. THE SOUTHERN OCEAN WATERS
AND THE LOWER DELAWARE BAY HAVE THE BEST CHANCE OF SEEING WIND GUSTS
NEAR 40 KNOTS DURING A TIME WINDOW OF 0100 UTC TO 0600 UTC THURSDAY.
FURTHER NORTH...THE GRADIENT IS ABOUT AS STRONG...BUT MODEL
SOUNDINGS ARE LESS BULLISH WITH THE MIXING. BOTTOM LINE...THE GALE
WARNING REMAINS IN PLACE...WITH THE STRONGEST WINDS ACROSS SOUTHERN
AREAS. THE GRADIENT STARTS TO RELAX TOWARD 0900 UTC...AND ALL WATERS
SHOULD BE BELOW GALE FORCE WINDS AT THAT TIME.
OUTLOOK...
CONDITIONS ARE EXPECTED TO DROP TO SMALL CRAFT ADVISORY LEVELS BY
THURSDAY MORNING...AND WINDS AND WAVES WILL SUBSIDE FURTHER THURSDAY
MORNING AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST.
THEN...SUB-ADVISORY CONDITIONS ARE FORECAST THURSDAY NIGHT INTO
SUNDAY. A FRONT MOVING IN FROM THE WEST SUNDAY NIGHT COULD PRECEDE
A PERIOD OF UNSETTLED WEATHER EARLY NEXT WEEK.
&&
.HYDROLOGY...
THE SECOND SLUG OF MOISTURE IS MOVING NORTHEAST WITH THE LOW LEVEL
JET...AND THE HEAVIEST RAIN HAS MOVED OUT OF THE WATCH AREA. SINCE
MOST PLACES THAT HAVE A THREAT ARE IN WARNINGS NOW...THE FLASH
FLOOD WATCH HAS BEEN CANCELLED. THERE COULD BE SOME MORE RIVER
FORECAST POINT WARNINGS...BUT THESE WOULD NOT BE COVERED BY A
FLASH FLOOD WARNING.
&&
.TIDES/COASTAL FLOODING...
TIDE DEPARTURES EARLY THIS MORNING WERE GENERALLY RUNNING BETWEEN
THREE-QUARTERS OF A FOOT AND ONE AND ONE-HALF FEET ABOVE PREDICTED.
THE LARGEST DEPARTURES WERE SEEN ALONG THE CENTRAL NEW JERSEY COAST
AND THE UPPER DELAWARE BAY.
THE HIGH TIDE ALONG THE OCEAN FRONT OCCURS BETWEEN 500 AM AND 630
AM...AND LATER ON THE BACK BAYS. THE ONSHORE FLOW SHOULD WEAKEN AS A
WARM FRONT MOVES NORTH...AND CROSSES MUCH OF THE AREA THIS MORNING.
HOWEVER...THE PILING OF WATER BY THE ONSHORE FLOW WILL BE MORE THAN
ENOUGH TO BRING MOST OCEAN LOCATIONS ABOVE THE MINOR TIDAL FLOODING
BENCHMARK.
SHOULD THE TIDAL DEPARTURES STAY THIS HIGH THROUGH THE MORNING HIGH
TIDE CYCLE...A FEW PLACES COULD GET CLOSE TO MODERATE (SUCH AS SANDY
HOOK...WHICH STAYS IN THE ONSHORE FLOW THE LONGEST). HOWEVER...THIS
IS NOT EXPECTED...AND ALL TIDE MODELS SUGGEST THAT THE DEPARTURES
START DROPPING AFTER THE PASSAGE OF THE WARM FRONT.
THE HIGH TIDE IN THE DELAWARE BAY OCCURS A BIT LATER (850 AM AT
REEDY POINT...FOR EXAMPLE). THE TIDE DEPARTURES THERE WOULD SUPPORT
MINOR TIDAL FLOODING...DESPITE THE FACT THAT ALL TIDE MODELS
REVIEWED FOR THE AREA SUGGEST TIDES WILL FALL SHORT OF THE
BENCHMARK. RIGHT NOW...IT APPEARS AS THOUGH THE HIGH TIDE FOR THE
DELAWARE RIVER WILL COME IN UNDER THE BENCHMARK. THIS WILL BE
MONITORED...AS THE DEPARTURE NOW WOULD SUPPORT REACHING THAT LEVEL.
THE LATE AFTERNOON AND EVENING TIDE IS ABOUT THREE-QUARTERS TO ONE
FOOT LOWER THAN THIS MORNING. WINDS SHOULD SHIFT TO THE NORTH...AND
INCREASE. THIS COULD RESULT IN THE DEVELOPMENT OF AN EKMAN SPIRAL
MASS TRANSPORT (BUT IT MAY NOT BE IN PLACE LONG ENOUGH TO MATTER)
TOWARD THE BEACH. RIGHT NOW...THIS TIDE DOES NOT APPEAR TO PRESENT A
PROBLEM.
THE NEXT TIDE OF INTEREST WOULD BE THE EARLY MORNING HIGH TIDE CYCLE
THURSDAY. DESPITE THE OFFSHORE WIND...THE MDL EXTRATROPICAL SURGE
MODEL IS SUGGESTING THAT THE OCEAN FRONT WILL SEE MINOR TIDAL
FLOODING. THIS IS MORE THAN 24 HOURS OUT...WITH PLENTY OF TIME TO
MONITOR TRENDS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ070-071.
NJ...COASTAL FLOOD ADVISORY UNTIL 9 AM EST THIS MORNING FOR
NJZ012>014-020>027.
COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NJZ016>019.
DE...COASTAL FLOOD ADVISORY UNTIL 9 AM EST THIS MORNING FOR
DEZ002>004.
COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
DEZ001.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-
431-450>455.
GALE WARNING FROM 6 PM THIS EVENING TO 4 AM EST THURSDAY FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...
AVIATION...HAYES
MARINE...HAYES
HYDROLOGY...HAYES
TIDES/COASTAL FLOODING...HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
316 AM EST WED NOV 23 2011
.SYNOPSIS...
INTENSIFYING LOW PRESSURE MOVING EASTWARD THROUGH PENNSYLVANIA EARLY
THIS MORNING...WITH A WARM FRONT EXTENDING EASTWARD INTO OUR
AREA...WILL PASS THROUGH OUR REGION LATER THIS MORNING AND EARLY
THIS AFTERNOON. THE TRAILING COLD FRONT WILL MOVE SOUTHEAST OF OUR
AREA BY EVENING. HIGH PRESSURE WILL BUILD INTO THE MID ATLANTIC
STATES THURSDAY AND FRIDAY AND SAG SOUTHWARD INTO THE CAROLINAS
THIS WEEKEND. A COLD FRONT MAY MOVE EASTWARD THROUGH OUR AREA
SUNDAY NIGHT INTO EARLY MONDAY. LOW PRESSURE DEVELOPING OVER THE
GREAT LAKES AND OHIO VALLEY AND EXTENDING INTO THE SOUTHEASTERN
STATES BY TUESDAY MAY AFFECT OUR AREA INTO THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FIRST SHOT OR PRECIPITATION HAS MOVED OUT...WITH THE NEXT SHOT
MOVING ACROSS AREAS NORTHWEST OF PHILADELPHIA. ALSO SEEING A LINE OF
SHOWERS WITH A WIND SHIFT MOVING INTO THE LEHIGH VALLEY. FINALLY...A
WARM FRONT CUTS ACROSS NORTHEAST MARYLAND...NORTHERN DELAWARE AND
SOUTHERN NEW JERSEY. NORTH OF THE FRONT...THE AREA IS MOSTLY RAIN
FREE AND WINDS HAVE SHIFTED TO THE SOUTH. THIS IS ALLOWING HIGHER
DEW POINTS TO ADVECT INTO THAT AREA.
THE MAIN WEATHER PROBLEM FOR TODAY WILL BE TIED TO A SURFACE COLD
FRONT. AHEAD OF THE FRONT...MOISTURE RICH AIR IS RIDING NORTHEAST ON
A 55 KNOT LOW LEVEL JET. FOR THE MOST PART...THE AIRMASS IS STABLE
EVEN SOUTH OF THE WARM FRONT. THERE IS INSTABILITY ACROSS SOUTHEAST
VIRGINIA...AND THIS COULD BE ADVECTED INTO SOUTHERN AREAS THIS
MORNING.
THE BEST CHANCE OF THUNDER WILL BE TIED TO THE INSTABILITY IN
SOUTHEAST VIRGINIA. THE HRRR ADVECTS THIS INSTABILITY INTO NORTHEAST
MARYLAND...DELAWARE AND SOUTHERN NEW JERSEY THROUGH ABOUT 1500 UTC.
BASED ON THIS...WILL HOLD ONTO THE MENTION OF THUNDER IN THESE
AREAS. THE BULK SHEAR VALUES WILL BE HIGH...BUT FOR NOW WILL HOLD
OFF ON ENHANCED WORDING FOR GUSTY WINDS.
THE HEAVIEST RAIN WILL FALL ACROSS EASTERN PENNSYLVANIA AND NORTHERN
NE JERSEY THIS MORNING. AN ADDITIONAL ONE TO ONE AND ONE-HALF INCHES
OF RAIN COULD FALL IN THE AIRMASS JUST AHEAD OF THE FRONT. THE
ADDITIONAL RAIN SHOULD RESULT IN FLOODING. MORE ON THE FLOODING
ISSUES IS INCLUDED IN THE HYDROLOGY SECTION BELOW.
AFTER THE FRONT PASSES...THE MAIN MOISTURE SHOULD BE SCOURED BY THE
FRONT AND EXITING LOW LEVEL JET. HOWEVER...THE MID LEVEL LONG WAVE
TROUGH STILL REMAINS TO THE WEST. WHILE WINDS SHIFTING TO THE WEST
BEHIND THE FRONT SHOULD DRY OUT OUT THE LOWER LEVELS...COLD MID
LEVEL TEMPERATURES AND SYNOPTIC SCALE LIFT AHEAD OF THE LONG WAVE
TROUGH COULD RESULT IN SHOWERS THIS AFTERNOON.
DESPITE THE LOW LEVEL DRYING BEHIND THE FRONT...ANY MEANINGFUL
CLEARING WILL HAVE TO WAIT UNTIL THE PASSAGE OF THE MID LEVEL
TROUGH. WITH THIS IN MIND...WILL REMAIN PESSIMISTIC WITH REGARD TO
SKY COVER FOR ALL AREAS. HIGHS SHOULD OCCUR BEFORE THE FRONT PASSES
THIS MORNING. TEMPERATURES ARE IN THE MID 60S ACROSS MUCH OF EASTERN
VIRGINIA...AND THIS SHOULD ADVECT INTO SOUTHERN AREAS.
THIS IS MORE OR LESS IN LINE WITH MOS VALUES...AND ARE ACCEPTED.
ELSEWHERE...HIGHS WERE MAINLY BASED ON THE MOS BLEND. IT IS POSSIBLE
THAT PORTIONS OF THE LEHIGH VALLEY AND SOUTHERN POCONOS MAY HAVE
TEMPERATURES BECOME STEADY OR SLOWLY FALL BEHIND THE MAIN FRONT
LATER THIS MORNING. THIS WAS ACCOUNTED FOR IN THE HOURLY TEMPERATURE
FORECAST.
FINALLY...THE GRADIENT STARTS TO TIGHTEN LATE THIS AFTERNOON AS
SURFACE LOW PRESSURE DEEPENS TO THE NORTHEAST. THE GRADIENT SUPPORTS
GUSTY WINDS IN JUST ABOUT ALL AREAS FROM MID AFTERNOON ON. MODEL
SOUNDINGS SUGGEST GUSTS TO 35 MPH ARE POSSIBLE TOWARD DARK...AS
WINDS SHIFT TO THE NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE BIGGEST ISSUE THIS EVENING WILL BE THE WIND. AS THE SURFACE LOW
DEEPENS TO THE NORTHEAST THIS EVENING...THE GRADIENT TIGHTENS
CONSIDERABLY. THE GRADIENT ITSELF WOULD SUPPORT WIND GUSTS TO 25 MPH
FOR JUST ABOUT ALL AREAS. HOWEVER...MODEL SOUNDINGS NEAR THE COAST
SUGGEST A THREE HOUR WIND CENTERED AROUND 0000 UTC WHEN 43 KNOTS OF
WIND MAY BE AVAILABLE AT THE TOP OF THE MIXED LAYER.
THIS IS ABOUT THE TIME OF THE BEST COLD AIR ADVECTION...WHEN
PRESSURE RISES OF 6 TO 7 MB IN 3 HOURS ARE FORECAST. THIS COULD
RESULT IN A SHORT PERIOD OF NEAR WIND ADVISORY TYPE WINDS...
ESPECIALLY FOR PORTION OF MARYLAND...DELAWARE AND SOUTHERN NEW
JERSEY. RIGHT NOW...THE CONFIDENCE DOES NOT EXIST FOR THE ISSUANCE
OF A WIND ADVISORY.
THE MID LEVEL LONG WAVE TROUGH SHOULD EXIT THE COAST DURING THE
EVENING (PROBABLY BEFORE 0300 UTC THURSDAY). WITH COLD MID LEVEL
TEMPERATURES AND SOME SYNOPTIC SCALE LIFT WITH THE TROUGH ITSELF...A
MENTION OF SHOWERS WAS LEFT IN PLACE FOR THE EVENING HOURS.
IN THE WAKE OF THE TROUGH...SKIES SHOULD CLEAR FAIRLY QUICKLY. THE
BEST GRADIENT OCCURS DURING THE EVENING...AND WEAKENS DURING THE
LATE PART OF THE OVERNIGHT. THE WEAKENING GRADIENT AND COOLING OF
THE LOWEST LEVELS COULD ALLOW SOME PROTECTED AREAS TO DECOUPLE LATER
TONIGHT. THIS COULD RESULT IN SOME OF THESE LOCATIONS DROPPING BELOW
MOS VALUES...BUT OVERALL...WITH A MIXED ENVIRONMENT MOST OF THE
NIGHT...LOWS WERE BASED ON THE MOS BLEND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE MODELS ARE A SOMEWHAT CONFIDENT ON INDICATING A COLD FRONT
MOVING INTO OR THROUGH OUR AREA SUNDAY NIGHT INTO EARLY MONDAY. IT
SEEMS TO BE AN ANAFRONT...SO HIGH CHANCE TO LOW LIKELY
PRECIPITATION CHANCES WERE USED SUNDAY NIGHT MAINLY WEST AND
CENTRAL. THEN...LOW PRESSURE FORMING SURFACE AND ALOFT ARE HANDLED
SLIGHTLY DIFFERENTLY BY THE 00Z GFS AND 00Z ECMWF...WITH THE
LATTER A LITTLE FURTHER SOUTH AND EAST WITH THE SURFACE LOW AS
COMPARED WITH THE GFS. HOWEVER...THE GENERAL EVOLUTION OF THE
AMPLIFYING UPPER PATTERN ON EACH IS SIMILAR. BUT, THIS MEANS A
GOOD DEAL OF UNCERTAINTY IN LOCATION AND TIMING OF FEATURES.
SO...AFTER SUNDAY NIGHT...A RATHER BROAD BRUSH WAS USED WITH HIGH
CHANCE PROBABILITIES GENERALLY EMPLOYED. AT THIS POINT, IT LOOKS
LIKE TUESDAY AND WEDNESDAY WILL FEATURE AT LEAST SOME
PRECIPITATION, AND IT COULD BE A SIGNIFICANT EVENT.
TEMPERATURES IN THE GRIDS WERE NOT TOO DIFFERENT FROM HPC
GUIDANCE PRODUCTS.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
MVFR/IFR CONDITIONS CONTINUE EARLY THIS MORNING ACROSS THE REGION.
THE FIRST SHOT OF STEADIER RANI HAS EXITED THE AREA...WITH SCATTERED
SHOWERS IN BETWEEN. THE NEXT SHOT OF RAIN IS WAITING ACROSS WESTERN
MARYLAND AND CENTRAL PENNSYLVANIA. AS THIS SHOT OF RAIN MOVES INTO
THE AREA...IFR CEILINGS ARE EXPECTED IN ALL AREAS.
LOW LEVEL WIND SHEAR IS NOW PRESENT IN THE KDIX VWP AND AMDAR
SOUNDINGS OUT OF KPHL...WITH 45 KNOTS AT 2000 FEET. THE GREATEST
EFFECTS OF THE OW LEVEL WIND SHEAR ARE BEING FELT FROM KPHL SOUTH
AND WEST. THIS IS IN RESPONSE TO A LOW LEVEL JET APPROACHING FROM
THE SOUTH SOUTHWEST. THE LOW LEVEL JET IS PUSHING THE NEXT SHOT OF
PRECIPITATION...AND LOW LEVEL WIND SHEAR IS EXPECTED THROUGH A COLD
FRONTAL PASSAGE LATE THIS MORNING.
A WEAK COLD FRONT WILL CROSS THE REGION BETWEEN 1100 UTC AND 1400
UTC. THIS FRONT WILL ONLY SERVE AS A WIND SHIFT...WITH LITTLE NI THE
WAY OF DRYING BEHIND. CEILINGS WILL REMAIN IFR THROUGH THE INITIAL
COLD FRONTAL PASSAGE. A MORE SIGNIFICANT FRONT WILL CROSS THE REGION
FROM WEST TO EAST BETWEEN 1600 UTC WEST AND 1900 UTC EAST. DRYING IN
THE LOWER LEVELS SHOULD HELP CEILINGS JUMP TO MVFR...WITH A FEW
SHOWERS POSSIBLE WITH THE FRONT. LOOKS FOR CEILINGS TO FINALLY GET
TO VFR BETWEEN 1900 UTC AND 2200 UTC...FROM WEST TO EAST.
WINDS WILL SHIFT TO THE WEST NORTHWEST BEHIND THE SECOND FRONT...AND
AS THE SURFACE GRADIENT INCREASES...SHOULD GUST TO 25 KNOTS FOR THE
MUCH OF THE REST OF THE AFTERNOON. AS LOW PRESSURE DEEPENS TO THE
NORTHEAST LATE THIS AFTERNOON AND TONIGHT...WINDS WILL SHIFT TO THE
NORTH. MODEL SOUNDINGS SUGGEST GUSTS BETWEEN 29 AND 35 KNOTS ARE
POSSIBLE FOR A TIME BETWEEN 0100 UTC AND 0600 UTC...WITH THE HIGHEST
GUSTS SOUTH AND EAST OF KPHL.
ALL TERMINALS SHOULD BE VFR BY 0000 UTC...AND SKIES WILL CLEAR
DURING THE EVENING HOURS.
OUTLOOK...
VFR CONDITIONS WILL OCCUR THURSDAY AND INTO MOST OF THE WEEKEND...
AS HIGH PRESSURE BUILDING INTO OUR AREA WILL LIKELY HANG ON INTO
SUNDAY. THURSDAY MAY START WITH SOMEWHAT GUSTY WINDS IN THE WAKE
OF WEDNESDAYS FRONT, AS THE GRADIENT IS STILL A LITTLE STRONG.
HOWEVER...ANY GUSTY MORNING WINDS SHOULD SETTLE DOWN IN THE
AFTERNOON. A FRONT MOVING IN FROM THE WEST MAY BRING SOME LOWER
CONDITIONS SUNDAY NIGHT INTO MONDAY. THEN...THE WEATHER BECOMES
MORE COMPLICATED AND UNCERTAIN, AS EXTENSIVE LOW PRESSURE WELL TO
OUR WEST OVER THE GREAT LAKES AND OHIO VALLEY AND INTO THE
SOUTHEAST IS LIKELY TO BE A WEATHER-MAKER FOR OUR AREA IN THE
EARLY AND MID PORTION OF NEXT WEEK. AVIATION CONDITIONS COULD BE
LOW THROUGH THIS PERIOD.
&&
.MARINE...
THE SURFACE WARM FRONT EXTENDS ACROSS NORTHERN DELAWARE AND THE
SOUTHERN THIRD OF NEW JERSEY EARLY THIS MORNING. NORTH OF THE
FRONT...EAST TO NORTHEAST WINDS REMAIN CLOSE TO SMALL CRAFT
LEVELS...WITH THE HIGHEST WINDS CLOSE TO SANDY HOOK. THE EASTERLY
FETCH HAS ALSO RESULTED IN SMALL CRAFT SEAS.
SOUTH OF THE FRONT...WINDS HAVE SHIFTED TO THE SOUTH...AND REMAIN
JUST BELOW SMALL CRAFT LEVELS. THE DEPTH OF THE MIXED LAYER PROBABLY
DOES NOT ALLOW THE MOMENTUM FROM THE PASSING LOW LEVEL JET TO MIX TO
THE SURFACE...SO WINDS PROBABLY STAY NEAR SMALL CRAFT LEVELS AHEAD
OF AN APPROACHING COLD FRONT. SEAS HERE ARE ALSO ABOVE 5 FEET...AS A
RESULT OF THE PREVIOUS EASTERLY SWELL..
THE WARM FRONT MAY NOT CLEAR THE ENTIRE COAST THIS MORNING BEFORE
THE COLD CROSSES. WINDS SHOULD REMAIN NEAR SMALL CRAFT LEVELS...BUT
AS MENTIONED EARLIER...THE MOMENTUM AHEAD OF THE FRONT PROBABLY DOES
NOT ALLOW ENOUGH MIXING FOR GALE FORCE WINDS FROM THE SOUTH. AFTER
THE FRONT PASSES...MODEL SOUNDINGS A PERIOD OF WEST WINDS WHICH MAY
NOT PRODUCE SMALL CRAFT WINDS IN ALL AREAS. HOWEVER...SEAS WILL
REMAIN NEAR 6 FEET ON THE OCEAN...AND PERHAPS 5 FEET ON THE LOWER
DELAWARE BAY.
AS LOW PRESSURE DEEPENS ON ITS WAY SOUTH OF NOVA SCOTIA THIS
EVENING...THE PRESSURE GRADIENT TIGHTENS CONSIDERABLY. THE GRADIENT
ITSELF IS BORDERLINE FOR GALES...BUT MODEL SOUNDINGS SHOW THE DEPTH
OF THE MIXED LAYER IN THE BEST COLD AIR ADVECTION INCREASING TO
ALLOW ACCESS TO 35 TO 40 KNOTS OF WIND. THE SOUTHERN OCEAN WATERS
AND THE LOWER DELAWARE BAY HAVE THE BEST CHANCE OF SEEING WIND GUSTS
NEAR 40 KNOTS DURING A TIME WINDOW OF 0100 UTC TO 0600 UTC THURSDAY.
FURTHER NORTH...THE GRADIENT IS ABOUT AS STRONG...BUT MODEL
SOUNDINGS ARE LESS BULLISH WITH THE MIXING. BOTTOM LINE...THE GALE
WARNING REMAINS IN PLACE...WITH THE STRONGEST WINDS ACROSS SOUTHERN
AREAS. THE GRADIENT STARTS TO RELAX TOWARD 0900 UTC...AND ALL WATERS
SHOULD BE BELOW GALE FORCE WINDS AT THAT TIME.
OUTLOOK...
CONDITIONS ARE EXPECTED TO DROP TO SMALL CRAFT ADVISORY LEVELS BY
THURSDAY MORNING...AND WINDS AND WAVES WILL SUBSIDE FURTHER THURSDAY
MORNING AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST.
THEN...SUB-ADVISORY CONDITIONS ARE FORECAST THURSDAY NIGHT INTO
SUNDAY. A FRONT MOVING IN FROM THE WEST SUNDAY NIGHT COULD PRECEDE
A PERIOD OF UNSETTLED WEATHER EARLY NEXT WEEK.
&&
.HYDROLOGY...
THE FIRST SLUG OF MOISTURE ASSOCIATED WITH STRONG WARM AIR ADVECTION
OVER THE SURFACE WARM FRONT PRODUCED 1 TO 2 INCHES OF RAIN ACROSS
EASTERN PENNSYLVANIA AND MUCH OF NEW JERSEY. SMALL STREAMS HAVE
RESPONDED AND FLOOD WARNINGS HAVE BEEN ISSUED. THE NEXT SLUG IS
AFFECTING THE LEHIGH VALLEY AND SOUTHERN POCONOS...AND IS MOVING
INTO NORTHWEST NEW JERSEY.
THIS SLUG OF MOISTURE IS BEING DRIVEN BY A 55 KNOT LOW LEVEL JET.
THE AIRMASS HAS PRECIPITABLE WATER VALUES REACHING NEAR 1.50
INCHES...AND IS STARTING TO PRESENT SOME CONVECTIVE CHARACTERISTICS.
THIS NEXT SLUG COULD PUSH SOME OF THE CREEKS AND STREAMS RUNNING
HIGH ACROSS EASTERN PENNSYLVANIA AND NORTH CENTRAL NEW JERSEY ABOVE
FLOOD...SO THE FLASH FLOOD WATCH REMAINS IN PLACE.
BASED ON THE TIMING OF THE COLD FRONT...MUCH OF THE HEAVY RAIN
SHOULD BE EAST OF THE WATCH AREA LATER THIS MORNING.
HOWEVER...RUNOFF MAY PRESENT PROBLEMS AFTER THIS...SO THE TIMING OF
THE WATCH REMAINS THE SAME. THE SOUTHERN POCONOS WERE ADDED TO THE
WATCH EARLIER...AS UPSTREAM HEAVY RAIN COULD BECOME A PROBLEM FOR
STREAMS AND CREEKS THERE.
&&
.TIDES/COASTAL FLOODING...
TIDE DEPARTURES EARLY THIS MORNING WERE GENERALLY RUNNING BETWEEN
THREE-QUARTERS OF A FOOT AND ONE AND ONE-HALF FEET ABOVE PREDICTED.
THE LARGEST DEPARTURES WERE SEEN ALONG THE CENTRAL NEW JERSEY COAST
AND THE UPPER DELAWARE BAY.
THE HIGH TIDE ALONG THE OCEAN FRONT OCCURS BETWEEN 500 AM AND 630
AM...AND LATER ON THE BACK BAYS. THE ONSHORE FLOW SHOULD WEAKEN AS A
WARM FRONT MOVES NORTH...AND CROSSES MUCH OF THE AREA THIS MORNING.
HOWEVER...THE PILING OF WATER BY THE ONSHORE FLOW WILL BE MORE THAN
ENOUGH TO BRING MOST OCEAN LOCATIONS ABOVE THE MINOR TIDAL FLOODING
BENCHMARK.
SHOULD THE TIDAL DEPARTURES STAY THIS HIGH THROUGH THE MORNING HIGH
TIDE CYCLE...A FEW PLACES COULD GET CLOSE TO MODERATE (SUCH AS SANDY
HOOK...WHICH STAYS IN THE ONSHORE FLOW THE LONGEST). HOWEVER...THIS
IS NOT EXPECTED...AND ALL TIDE MODELS SUGGEST THAT THE DEPARTURES
START DROPPING AFTER THE PASSAGE OF THE WARM FRONT.
THE HIGH TIDE IN THE DELAWARE BAY OCCURS A BIT LATER (850 AM AT
REEDY POINT...FOR EXAMPLE). THE TIDE DEPARTURES THERE WOULD SUPPORT
MINOR TIDAL FLOODING...DESPITE THE FACT THAT ALL TIDE MODELS
REVIEWED FOR THE AREA SUGGEST TIDES WILL FALL SHORT OF THE
BENCHMARK. RIGHT NOW...IT APPEARS AS THOUGH THE HIGH TIDE FOR THE
DELAWARE RIVER WILL COME IN UNDER THE BENCHMARK. THIS WILL BE
MONITORED...AS THE DEPARTURE NOW WOULD SUPPORT REACHING THAT LEVEL.
THE LATE AFTERNOON AND EVENING TIDE IS ABOUT THREE-QUARTERS TO ONE
FOOT LOWER THAN THIS MORNING. WINDS SHOULD SHIFT TO THE NORTH...AND
INCREASE. THIS COULD RESULT IN THE DEVELOPMENT OF AN EKMAN SPIRAL
MASS TRANSPORT (BUT IT MAY NOT BE IN PLACE LONG ENOUGH TO MATTER)
TOWARD THE BEACH. RIGHT NOW...THIS TIDE DOES NOT APPEAR TO PRESENT A
PROBLEM.
THE NEXT TIDE OF INTEREST WOULD BE THE EARLY MORNING HIGH TIDE CYCLE
THURSDAY. DESPITE THE OFFSHORE WIND...THE MDL EXTRATROPICAL SURGE
MODEL IS SUGGESTING THAT THE OCEAN FRONT WILL SEE MINOR TIDAL
FLOODING. THIS IS MORE THAN 24 HOURS OUT...WITH PLENTY OF TIME TO
MONITOR TRENDS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR PAZ054-055-
060>062-067>071.
COASTAL FLOOD ADVISORY FROM 8 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR PAZ070-071.
NJ...FLASH FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR NJZ001-
007>010-012-015.
COASTAL FLOOD ADVISORY UNTIL 9 AM EST THIS MORNING FOR
NJZ012>014-020>027.
COASTAL FLOOD ADVISORY FROM 8 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR NJZ016>019.
DE...FLASH FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR DEZ001.
COASTAL FLOOD ADVISORY UNTIL 9 AM EST THIS MORNING FOR
DEZ002>004.
COASTAL FLOOD ADVISORY FROM 8 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR DEZ001.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-
431-450>455.
GALE WARNING FROM 6 PM THIS EVENING TO 4 AM EST THURSDAY FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...
AVIATION...HAYES
MARINE...HAYES
HYDROLOGY...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
852 PM CST THU NOV 24 2011
.DISCUSSION...
ISSUED 852 PM CST THU NOV 24 2011
LOW STRATUS IS COMING BACK NORTH...AIDED BY STRONG SOUTHERLY
WINDS. THIS AREA OF CLOUDS IS NOT VERY WIDE SO SOME AREAS IN THE
SOUTHEAST COULD SEE SOME CLEARING OVERNIGHT...WHILE OTHER AREAS
BECOME CLOUDY AGAIN. CURRENT FORECAST SEEMS TO HAVE A GOOD HANDLE
ON THE GOING TRENDS SO NO UPDATE REQUIRED AT THIS TIME.
HOWEVER...HAVE BEEN MAKING ADJUSTMENTS TO THE GRIDS TO BETTER
REFLECT THE CLOUD COVER TRENDS.
AUTEN
&&
.AVIATION...
ISSUED 545 PM CST THU NOV 24 2011
LOW CLOUDS HAVE FINALLY DISSIPATED OR MOVED EAST OF THE TAF SITES
THIS AFTERNOON. HOWEVER...SATELLITE LOOP OF LOWER CLOUDS SHOWS
THEM ADVECTING BACK TO THE NORTHWEST THIS EVENING AND SPREADING
OVER THE SITES THIS EVENING AND INTO OVERNIGHT. THESE LOWER CLOUDS
WILL DISSIPATE TOMORROW AFTERNOON...BUT CIRRUS WILL REMAIN. WINDS
WILL REMAIN SOUTHERLY OVERNIGHT WITH LOW LEVEL WINDS INCREASING
AFTER MIDNIGHT TO AROUND 40KTS AT 1.5KFT. SO WILL KEEP WS IN
FORECAST FOR ALL SITES. ONCE CLOUDS DISSIPATE THEN SFC WINDS WILL
INCREASE OUT OF THE SSE WITH GUSTS TO AROUND 25-57KTS.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 300 PM CST THU NOV 24 2011
INITIAL CONCERN WILL BE POSSIBLE REDEVELOPMENT OF LOW STRATUS
CLOUDS TONIGHT INTO FRIDAY MORNING. THEN ATTENTION TURNS TO THE
ONSET OF RAIN LATE FRIDAY NIGHT THROUGH SATURDAY AND THE ARRIVAL
OF COLDER AIR FOR MUCH OF THE EXTENDED FORECAST.
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
CHALLENGING FORECAST FOR TONIGHT IN TERMS OF CLOUDS AND RESULTANT
LOW TEMPS. THE ONLY MODELS THAT SEEM TO HAVE A DECENT HANDLE ON
THE LOW LEVEL MOISTURE ARE THE HRRR AND SPC 4KM WRF. BOTH OF THEM
ARE INDICATING CLOUD REDEVELOPMENT ACROSS CENTRAL IL AND EVEN
SURROUNDING PORTIONS OF IL. THE NAM AND GFS SOUNDINGS SHOW A LOW
LEVEL SATURATION AS WELL...BUT SHALLOW. FORECAST WIND TRAJECTORY
FLOWS INDICATE WE SHOULD SEE THE SW RETURN FLOW ORIGINATING WHERE
STRATUS CLOUDS ARE LINGERING THIS AFTERNOON IN MO/AR. A TIGHTER
PRESSURE GRADIENT WOULD TYPICALLY KEEP WINDS UP AT NIGHT...BUT THE
LOW LEVEL INVERSION LOOKS TO BE PLENTY STRONG ENOUGH TO PREVENT
MIXING OVERNIGHT. WILL FORECAST CLOUDS TO REFORM...AND KEEP LOW
TEMPS A COUPLE DEGREES WARMER THAN GUIDANCE.
CLEARING SHOULD COME QUICKER ON FRIDAY AS MORE PROMINENT MIXING
WILL OCCUR UNDER A MUCH STRONGER SFC PRESSURE GRADIENT. PLENTY OF
DRY AIR ALOFT WILL AID IN CLOUD EROSION. WINDY CONDITIONS ARE
EXPECTED WITH SSW GUSTS OVER 30 MPH. TEMPS WILL RESPOND IN KIND AS
WAA FLOWS PUSH 850 MB TEMPS UP NEAR 12C. THAT COUPLED WITH ADDITIONAL
SUNSHINE SHOULD PUT HIGHS INTO THE L-M 60S.
BROAD SCALE ISENTROPIC LIFT AHEAD OF THE NEXT COLD FRONT WILL HELP
PRIME THE ATMOSPHERE FOR RAIN TO DEVELOP W OF THE IL RIVER AFTER
MIDNIGHT FRIDAY NIGHT. HOWEVER...BASED ON FORECAST CONDENSATION
PRESSURE DEFICITS /CPD/...IT STILL APPEARS WE WILL HAVE A 5-7 HOUR
WINDOW OF STEADY RAINS AS THE FRONT PROGRESSES EASTWARD DURING THE
DAY ON SATURDAY. WE WILL CONTINUE WITH CATEGORICAL POPS WEST IN
THE MORNING AND EAST IN THE AFTERNOON. SOME SHOWERS MAY LINGER IN
THE EVENING ACROSS THE EAST...SO WILL CONTINUE WITH CHANCE POPS AS
SUBSIDENT FLOWS BEGIN TO SHUT DOWN MEASURABLE PRECIP.
COLD AIR WILL RETURN ON BRISK NW WINDS SAT NIGHT. MOST OF THE
PRECIP SHOULD COME TO AN END BEFORE THE AIR COLUMN GETS COLD
ENOUGH FOR SNOW. HOWEVER...WE CAN NOT RULE OUT SOME FLURRIES
POSSIBLE AFTER MIDNIGHT SAT NIGHT. BY 12Z SUNDAY...ANOTHER WAVE OF
ISENTROPIC LIFT AND LOW CPD/S IS INDICATED AS THE UPPER TROUGH MOVES
ACROSS IL. ENOUGH RESIDUAL MOISTURE MAY BE PRESENT FOR A FEW LIGHT
RAIN/SNOW SHOWERS AFTER MIDNIGHT...AND FLURRIES NORTH/SPRINKLES
SOUTH ON SUNDAY.
BY SUNDAY NIGHT...ALL PRECIP SHOULD COME TO AN END FROM THIS
SYSTEM...AS THE UPPER TROUGH AXIS FINALLY SLIDES EAST.
LONG TERM...MONDAY THROUGH THURSDAY.
THE EXTENDED FORECAST SHOWS PERSISTENT COLD CONDITIONS AS A CUT
OFF LOW POSSIBLY DEVELOPS ACROSS THE SOUTHERN OHIO RIVER VALLEY.
THERE HAS BEEN A WIDE VARIETY OF SOLUTIONS FROM THE MODELS ON THIS
CUT OFF FEATURE...WITH THE ECMWF AND THE CANADIAN THE MAIN ONES
SHOWING THIS FEATURE. THE ECMWF BEING A BIT MORE PRONOUNCED AND
SLOWER THAN THE CANADIAN. THE GFS KEEPS A PROGRESSIVE PATTERN WITH
NORTHWEST FLOW AND A DRY FRONTAL PASSAGE ON MONDAY NIGHT/TUESDAY
ACROSS IL. DESPITE THE DIFFERING SOLUTIONS...THE OVERALL SENSIBLE
WEATHER LOOKS TO BE ON THE CHILLY SIDE WITH PERIODICALLY BREEZY
CONDITIONS.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
545 PM CST THU NOV 24 2011
.DISCUSSION...
ISSUED 300 PM CST THU NOV 24 2011
INITIAL CONCERN WILL BE POSSIBLE REDEVELOPMENT OF LOW STRATUS
CLOUDS TONIGHT INTO FRIDAY MORNING. THEN ATTENTION TURNS TO THE
ONSET OF RAIN LATE FRIDAY NIGHT THROUGH SATURDAY AND THE ARRIVAL
OF COLDER AIR FOR MUCH OF THE EXTENDED FORECAST.
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
CHALLENGING FORECAST FOR TONIGHT IN TERMS OF CLOUDS AND RESULTANT
LOW TEMPS. THE ONLY MODELS THAT SEEM TO HAVE A DECENT HANDLE ON
THE LOW LEVEL MOISTURE ARE THE HRRR AND SPC 4KM WRF. BOTH OF THEM
ARE INDICATING CLOUD REDEVELOPMENT ACROSS CENTRAL IL AND EVEN
SURROUNDING PORTIONS OF IL. THE NAM AND GFS SOUNDINGS SHOW A LOW
LEVEL SATURATION AS WELL...BUT SHALLOW. FORECAST WIND TRAJECTORY
FLOWS INDICATE WE SHOULD SEE THE SW RETURN FLOW ORIGINATING WHERE
STRATUS CLOUDS ARE LINGERING THIS AFTERNOON IN MO/AR. A TIGHTER
PRESSURE GRADIENT WOULD TYPICALLY KEEP WINDS UP AT NIGHT...BUT THE
LOW LEVEL INVERSION LOOKS TO BE PLENTY STRONG ENOUGH TO PREVENT
MIXING OVERNIGHT. WILL FORECAST CLOUDS TO REFORM...AND KEEP LOW
TEMPS A COUPLE DEGREES WARMER THAN GUIDANCE.
CLEARING SHOULD COME QUICKER ON FRIDAY AS MORE PROMINENT MIXING
WILL OCCUR UNDER A MUCH STRONGER SFC PRESSURE GRADIENT. PLENTY OF
DRY AIR ALOFT WILL AID IN CLOUD EROSION. WINDY CONDITIONS ARE
EXPECTED WITH SSW GUSTS OVER 30 MPH. TEMPS WILL RESPOND IN KIND AS
WAA FLOWS PUSH 850 MB TEMPS UP NEAR 12C. THAT COUPLED WITH ADDITIONAL
SUNSHINE SHOULD PUT HIGHS INTO THE L-M 60S.
BROAD SCALE ISENTROPIC LIFT AHEAD OF THE NEXT COLD FRONT WILL HELP
PRIME THE ATMOSPHERE FOR RAIN TO DEVELOP W OF THE IL RIVER AFTER
MIDNIGHT FRIDAY NIGHT. HOWEVER...BASED ON FORECAST CONDENSATION
PRESSURE DEFICITS /CPD/...IT STILL APPEARS WE WILL HAVE A 5-7 HOUR
WINDOW OF STEADY RAINS AS THE FRONT PROGRESSES EASTWARD DURING THE
DAY ON SATURDAY. WE WILL CONTINUE WITH CATEGORICAL POPS WEST IN
THE MORNING AND EAST IN THE AFTERNOON. SOME SHOWERS MAY LINGER IN
THE EVENING ACROSS THE EAST...SO WILL CONTINUE WITH CHANCE POPS AS
SUBSIDENT FLOWS BEGIN TO SHUT DOWN MEASURABLE PRECIP.
COLD AIR WILL RETURN ON BRISK NW WINDS SAT NIGHT. MOST OF THE
PRECIP SHOULD COME TO AN END BEFORE THE AIR COLUMN GETS COLD
ENOUGH FOR SNOW. HOWEVER...WE CAN NOT RULE OUT SOME FLURRIES
POSSIBLE AFTER MIDNIGHT SAT NIGHT. BY 12Z SUNDAY...ANOTHER WAVE OF
ISENTROPIC LIFT AND LOW CPD/S IS INDICATED AS THE UPPER TROUGH MOVES
ACROSS IL. ENOUGH RESIDUAL MOISTURE MAY BE PRESENT FOR A FEW LIGHT
RAIN/SNOW SHOWERS AFTER MIDNIGHT...AND FLURRIES NORTH/SPRINKLES
SOUTH ON SUNDAY.
BY SUNDAY NIGHT...ALL PRECIP SHOULD COME TO AN END FROM THIS
SYSTEM...AS THE UPPER TROUGH AXIS FINALLY SLIDES EAST.
LONG TERM...MONDAY THROUGH THURSDAY.
THE EXTENDED FORECAST SHOWS PERSISTENT COLD CONDITIONS AS A CUT
OFF LOW POSSIBLY DEVELOPS ACROSS THE SOUTHERN OHIO RIVER VALLEY.
THERE HAS BEEN A WIDE VARIETY OF SOLUTIONS FROM THE MODELS ON THIS
CUT OFF FEATURE...WITH THE ECMWF AND THE CANADIAN THE MAIN ONES
SHOWING THIS FEATURE. THE ECMWF BEING A BIT MORE PRONOUNCED AND
SLOWER THAN THE CANADIAN. THE GFS KEEPS A PROGRESSIVE PATTERN WITH
NORTHWEST FLOW AND A DRY FRONTAL PASSAGE ON MONDAY NIGHT/TUESDAY
ACROSS IL. DESPITE THE DIFFERING SOLUTIONS...THE OVERALL SENSIBLE
WEATHER LOOKS TO BE ON THE CHILLY SIDE WITH PERIODICALLY BREEZY
CONDITIONS.
SHIMON
&&
.AVIATION...
ISSUED 545 PM CST THU NOV 24 2011
LOW CLOUDS HAVE FINALLY DISSIPATED OR MOVED EAST OF THE TAF SITES
THIS AFTERNOON. HOWEVER...SATELLITE LOOP OF LOWER CLOUDS SHOWS
THEM ADVECTING BACK TO THE NORTHWEST THIS EVENING AND SPREADING
OVER THE SITES THIS EVENING AND INTO OVERNIGHT. THESE LOWER CLOUDS
WILL DISSIPATE TOMORROW AFTERNOON...BUT CIRRUS WILL REMAIN. WINDS
WILL REMAIN SOUTHERLY OVERNIGHT WITH LOW LEVEL WINDS INCREASING
AFTER MIDNIGHT TO AROUND 40KTS AT 1.5KFT. SO WILL KEEP WS IN
FORECAST FOR ALL SITES. ONCE CLOUDS DISSIPATE THEN SFC WINDS WILL
INCREASE OUT OF THE SSE WITH GUSTS TO AROUND 25-57KTS.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
248 PM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NO SHORT TERM CONCERNS.
* POTENTIAL FOR RETURN TO MVFR CONDITIONS DURING OVERNIGHT AND
EARLY THU MORNING.
TRS
//DISCUSSION...UPDATED 18Z...
AREA OF LOW STRATUS AND BR OVER NE IL HAS BEEN ERODING AWAY WITH
CONTINUED SURFACE HEATING...WITH SUNSHINE UNIMPEDED BY ANY HIGHER
CLOUDS. AFTERNOON INTO EVENING EXPECTED TO BE SKC ACROSS THE
LOCAL TERMINALS WITH LIGHT LOW LEVEL FLOW GRADUALLY BACKING TO WSW
AND SW AS THE SURFACE RIDGE CURRENTLY JUST ABOUT OVERHEAD SLIPS
OFF TO THE E.
A LARGE AREA OF STRATUS OVER MUCH OF WI...IA...MO AND THE S HALF
OF IL HAS BEEN GRADUALLY DIMINISHING WITH TIME THIS MORNING AND
EARLY AFTERNOON BUT FEEL THAT A PORTION OF IT WILL SURVIVE
THROUGH THE REST OF THE DAY GIVEN HOW SOON THE SUN GETS LOW ON THE
HORIZON THIS TIME OF YEAR.
WITH SW FLOW GRADUALLY INCREASING DURING THE NIGHT AND EARLY THU
MORNING EXPECT TO SEE SOME OF THIS STRATUS SPREADING INTO NORTHERN
IL AND EVENTUALLY TO THE LOCAL TERMINALS. SOMEWHAT CONFIDENT THIS
WILL OCCUR BASED ON NAM LOW LEVEL RH PROGS AS THIS MODEL HAD THE
BEST DEPICTION OF THIS LARGE ARC OF STRATUS IN THE SHORT TERM.
BASED ON THESE PROGS...EXPECT TO SEE THE STRATUS OVERSPREAD THE
LOCAL TERMINALS SW TO NE BETWEEN 09Z AND 11Z WED.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE LIGHT W-SW WINDS GRADUALLY BECOMING SW DURING
THE REST OF THE DAY...THEN INCREASING SLIGHTLY THIS EVENING.
* MODERATE CONFIDENCE IFR...POSSIBLY LIFR...CIGS RETURNING DURING
LATE NIGHT AND PREDAWN THU.
* LOW CONFIDENCE IN TIMING OF ARRIVAL OF STRATUS CLOUDS OVERNIGHT
WITH 09Z-11Z TIME FRAME +/- A COUPLE HRS BEST ESTIMATE ATTM.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY THROUGH TUESDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND
POSSIBLY A FEW SHSN. CMS
&&
.MARINE...
244 PM CST
ACTIVE WEATHER WILL BE RETURNING TO LAKE MICHIGAN OVER THE NEXT
SEVERAL DAYS AS A SERIES OF LOW PRESSURE SYSTEMS CROSS THE REGION.
LOW PRESSURE ACROSS NORTHERN ONTARIO THIS AFTERNOON WILL CONTINUE
ACROSS JAMES BAY THIS EVENING WHILE HIGH PRESSURE MOVES EASTWARD
ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. THE PRESSURE GRADIENT
WILL TIGHTEN ACROSS THE NORTHERN PART OF THE LAKE INTO THE EVENING
ALLOWING SOUTHWESTERLY WINDS TO INCREASE WITH GUSTS PUSHING 30 KT
THIS EVENING. THERE IS AN OUTSIDE CHANCE THERE MAY BE A FEW GALE
FORCE GUSTS TO 35 KT FOR A SHORT TIME THIS EVENING FROM THE MANITOU
ISLANDS NORTH TOWARDS THE STRAITS OF MACKINAC. WINDS WILL INCREASE
MORE MODESTLY ACROSS THE SOUTH HALF OF THE LAKE. WINDS MAY DIMINISH
SLIGHTLY EARLY THURSDAY BUT WILL PICK UP AGAIN THURSDAY MORNING AND
ESPECIALLY THURSDAY AFTERNOON AND EVENING AS LOW PRESSURE CURRENTLY
OVER SOUTHERN ALBERTA TRACKS EASTWARD ACROSS NORTHERN ONTARIO
REACHING JAMES BY BY THURSDAY EVENING. EXPECT THAT WINDS TO 30 KT
WILL OCCUR ACROSS THE LAKE AND THAT 35 KT GALES MAY OCCUR NORTH
THURSDAY EVENING BUT THIS CHANCE FOR THIS WILL BE SOMEWHAT MARGINAL
SO WILL MENTION WINDS TO 30 AND POSSIBLE GALE FORCE GUSTS DURING
THIS TIME. WEAK HIGH PRESSURE WILL FILL IN BEHIND THE LOW LATER
FRIDAY BRINGING A DECREASE IN WIND SPEEDS...ESPECIALLY NORTH...BUT
ANOTHER LOW WILL DEVELOP ACROSS THE CENTRAL PLAINS AND MOVE
NORTHEASTWARD TOWARD NORTHERN LAKE MICHIGAN FRIDAY NIGHT AND
SATURDAY. TIMING THE PASSAGE OF THIS LOW HAS BEEN A BIT TRICKY BUT
HAVE DECENT CONFIDENCE IN IT REACHING THE UPPER PENINSULA/NORTHERN
LAKE MICHIGAN BY SATURDAY EVENING WITH THE ASSOCIATED COLD FRONT
CROSSING THE LAKE AROUND THAT TIME. SHOULD SEE AN INCREASE IN
SOUTH/SOUTHWEST WINDS DURING THE DAY SATURDAY AHEAD OF THE FRONT
WITH A BIT OF A LULL WITH THE FRONTAL PASSAGE FOLLOWED BY AN
INCREASE FROM THE WEST THEN NORTHWEST SATURDAY NIGHT AS THE LOW
PASSES AND THE PRESSURE GRADIENT TIGHTENS.
HIGH PRESSURE THEN RETURNS SUNDAY NIGHT WITH MUCH LIGHTER WINDS
SETTING UP BUT ANOTHER LOW WILL BE MOVING ACROSS THE CANADIAN
PRAIRIES LATER MONDAY AND HEADING FOR THE AREA FOR TUESDAY. FORECAST
MODELS SHOW GOOD AGREEMENT ON THE PRESENCE OF A LOW BUT VARY WITH
MAGNITUDE. WILL HOLD WINDS AT 30 KT FROM LATE TUESDAY AFTERNOON AND
TUESDAY NIGHT BUT WILL NEED TO KEEP AN EYE ON THE POTENTIAL FOR
GALES.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
233 PM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NO SHORT TERM CONCERNS.
* POTENTIAL FOR RETURN TO MVFR CONDITIONS DURING OVERNIGHT AND
EARLY THU MORNING.
TRS
//DISCUSSION...UPDATED 18Z...
AREA OF LOW STRATUS AND BR OVER NE IL HAS BEEN ERODING AWAY WITH
CONTINUED SURFACE HEATING...WITH SUNSHINE UNIMPEDED BY ANY HIGHER
CLOUDS. AFTERNOON INTO EVENING EXPECTED TO BE SKC ACROSS THE
LOCAL TERMINALS WITH LIGHT LOW LEVEL FLOW GRADUALLY BACKING TO WSW
AND SW AS THE SURFACE RIDGE CURRENTLY JUST ABOUT OVERHEAD SLIPS
OFF TO THE E.
A LARGE AREA OF STRATUS OVER MUCH OF WI...IA...MO AND THE S HALF
OF IL HAS BEEN GRADUALLY DIMINISHING WITH TIME THIS MORNING AND
EARLY AFTERNOON BUT FEEL THAT A PORTION OF IT WILL SURVIVE
THROUGH THE REST OF THE DAY GIVEN HOW SOON THE SUN GETS LOW ON THE
HORIZON THIS TIME OF YEAR.
WITH SW FLOW GRADUALLY INCREASING DURING THE NIGHT AND EARLY THU
MORNING EXPECT TO SEE SOME OF THIS STRATUS SPREADING INTO NORTHERN
IL AND EVENTUALLY TO THE LOCAL TERMINALS. SOMEWHAT CONFIDENT THIS
WILL OCCUR BASED ON NAM LOW LEVEL RH PROGS AS THIS MODEL HAD THE
BEST DEPICTION OF THIS LARGE ARC OF STRATUS IN THE SHORT TERM.
BASED ON THESE PROGS...EXPECT TO SEE THE STRATUS OVERSPREAD THE
LOCAL TERMINALS SW TO NE BETWEEN 09Z AND 11Z WED.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE LIGHT W-SW WINDS GRADUALLY BECOMING SW DURING
THE REST OF THE DAY...THEN INCREASING SLIGHTLY THIS EVENING.
* MODERATE CONFIDENCE IFR...POSSIBLY LIFR...CIGS RETURNING DURING
LATE NIGHT AND PREDAWN THU.
* LOW CONFIDENCE IN TIMING OF ARRIVAL OF STRATUS CLOUDS OVERNIGHT
WITH 09Z-11Z TIME FRAME +/- A COUPLE HRS BEST ESTIMATE ATTM.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY THROUGH TUESDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND
POSSIBLY A FEW SHSN. CMS
&&
.MARINE...
300 AM CST
WITH LOW PRESSURE QUICKLY SHIFTING EAST OF THE LAKE THIS MORNING AND
HIGH PRESSURE SLOWLY BUILDING EAST THROUGH THE UPPER MIDWEST...WINDS
HAVE BEEN DIMINISHING ACROSS THE LAKE. WINDS WILL CONTINUE TO
DIMINISH AS THIS HIGH SHIFTS EAST TODAY WITH A BRIEF PERIOD OF
LIGHTER FLOW. ALTHOUGH WITH THIS HIGH CONTINUING TO THE EAST
TONIGHT...A FAIRLY ACTIVE SURFACE PATTERN WILL BE IN PLACE TO THE
NORTHWEST OF THE GREAT LAKES. THIS WILL PROVIDE A STRENGTHENING
PRESSURE GRADIENT OVER THE LAKE WITH WINDS INCREASING ONCE AGAIN.
THIS INCREASE IN WINDS WILL INITIALLY OCCUR OVER THE NORTHERN HALF
OF THE LAKE BUT WITH WINDS EVENTUALLY INCREASING OVER THE SOUTHERN
HALF LAKE TONIGHT INTO THURSDAY. WITH THIS HIGH REMAINING TO THE
SOUTHEAST OF THE LAKE AND THIS ACTIVE SURFACE PATTERN TO THE
NORTHWEST...A PERIOD OF STRONG SOUTHERLY FLOW WILL BE IN PLACE
THROUGH THE END OF THE WORK WEEK. ALTHOUGH THIS WEATHER PATTERN WILL
SUPPORT STRENGTHENING WINDS INTO FRIDAY...A WARMER AIR MASS WILL
MOVE ACROSS THE LAKE. THIS COULD PROVIDE MORE STABLE CONDITIONS AND
THUS LIMIT THE AMOUNT OF STRONGER WINDS ALOFT TO REACH THE SURFACE
OF THE LAKE. HAVE KEPT WINDS JUST BELOW GALES THURSDAY NIGHT INTO
FRIDAY DUE TO THIS WARMER AIR...BUT WILL HAVE TO CONTINUE TO MONITOR
LATER GUIDANCE TO ASSESS THE POSSIBILITY OF THESE STRONGER WINDS
ALOFT TO REACH THE SURFACE OF THE LAKE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1157 AM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* POTENTIAL FOR RETURN TO MVFR CONDITIONS DURING OVERNIGHT AND
EARLY THU MORNING.
TRS
//DISCUSSION...UPDATED 18Z...
AREA OF LOW STRATUS AND BR OVER NE IL HAS BEEN ERODING AWAY WITH
CONTINUED SURFACE HEATING WITH SUNSHINE UNIMPEDED BY ANY HIGHER
CLOUDS. AFTERNOON INTO EVENING EXPECTED TO BY SKC ACROSS THE LOCAL
TERMINALS WITH LIGHT LOW LEVEL FLOW GRADUALLY BACKING TO WSW AND
SW AS THE SURFACE RIDGE CURRENTLY JUST ABOUT OVERHEAD SLIPS OFF TO
THE E.
A LARGE AREA OF STRATUS OVER MUCH OF WI...IA...MO AND THE S HALF
OF IL HAS BEEN GRADUALLY DIMINISHING WITH TIME THIS MORNING BUT
FEE THAT IT A PORTION OF IT WILL SURVIVE THROUGH THE REST OF THE
DAY GIVEN HOW SOON THE SUN GETS LOW ON THE HORIZON. WITH SW FLOW
GRADUALLY INCREASING DURING THE NIGHT AND EARLY THU MORNING
EXPECT TO SEE SOME OF THIS STRATUS SPREADING INTO NORTHERN IL AND
EVENTUALLY TO THE LOCAL TERMINALS. SOMEWHAT CONFIDENT THIS WILL
OCCUR BASED ON NAM LOW LEVEL RH PROGS AS THIS MODEL HAD THE BEST
DEPICTION OF THIS LARGE ARC OF STRATUS IN SHORT TERM. BASED ON
THESE PROGS EXPECT TO SEE THE STRATUS OVERSPREAD THE LOCAL
TERMINALS SW TO NE BETWEEN 09Z AND 11Z WED.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE LIGHT NW-W WINDS GRADUALLY BECOMING W-SW DURING
THE REST OF THE DAY...THEN INCREASING OUT OF THE SW AFTER
SUNRISE WED.
* MODERATE CONFIDENCE IFR...POSSIBLY LIFR...CIGS RETURNING DURING
LATE NIGHT AND PREDAWN HOURS.
* LOW CONFIDENCE IN TIMING OF ARRIVAL OF STRATUS CLOUDS OVERNIGHT
WITH 09Z-11Z TIME FRAME +/- A COUPLE HRS BEST ESTIMATE ATTM.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY THROUGH TUESDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND
POSSIBLY A FEW SHSN. CMS
&&
.MARINE...
300 AM CST
WITH LOW PRESSURE QUICKLY SHIFTING EAST OF THE LAKE THIS MORNING AND
HIGH PRESSURE SLOWLY BUILDING EAST THROUGH THE UPPER MIDWEST...WINDS
HAVE BEEN DIMINISHING ACROSS THE LAKE. WINDS WILL CONTINUE TO
DIMINISH AS THIS HIGH SHIFTS EAST TODAY WITH A BRIEF PERIOD OF
LIGHTER FLOW. ALTHOUGH WITH THIS HIGH CONTINUING TO THE EAST
TONIGHT...A FAIRLY ACTIVE SURFACE PATTERN WILL BE IN PLACE TO THE
NORTHWEST OF THE GREAT LAKES. THIS WILL PROVIDE A STRENGTHENING
PRESSURE GRADIENT OVER THE LAKE WITH WINDS INCREASING ONCE AGAIN.
THIS INCREASE IN WINDS WILL INITIALLY OCCUR OVER THE NORTHERN HALF
OF THE LAKE BUT WITH WINDS EVENTUALLY INCREASING OVER THE SOUTHERN
HALF LAKE TONIGHT INTO THURSDAY. WITH THIS HIGH REMAINING TO THE
SOUTHEAST OF THE LAKE AND THIS ACTIVE SURFACE PATTERN TO THE
NORTHWEST...A PERIOD OF STRONG SOUTHERLY FLOW WILL BE IN PLACE
THROUGH THE END OF THE WORK WEEK. ALTHOUGH THIS WEATHER PATTERN WILL
SUPPORT STRENGTHENING WINDS INTO FRIDAY...A WARMER AIR MASS WILL
MOVE ACROSS THE LAKE. THIS COULD PROVIDE MORE STABLE CONDITIONS AND
THUS LIMIT THE AMOUNT OF STRONGER WINDS ALOFT TO REACH THE SURFACE
OF THE LAKE. HAVE KEPT WINDS JUST BELOW GALES THURSDAY NIGHT INTO
FRIDAY DUE TO THIS WARMER AIR...BUT WILL HAVE TO CONTINUE TO MONITOR
LATER GUIDANCE TO ASSESS THE POSSIBILITY OF THESE STRONGER WINDS
ALOFT TO REACH THE SURFACE OF THE LAKE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1155 AM CST WED NOV 23 2011
.DISCUSSION...
ISSUED 950 AM CST WED NOV 23 2011
WILL UPDATE THE FORECAST LATE THIS MORNING AS THE FOG LIFTS INTO
MIDDAY WITH SKIES BECOMING MOSTLY SUNNY THIS AFTERNOON. OTHERWISE
REST OF FORECAST LOOKS ON TRACK WITH HIGHS IN THE LOWER 50S AND
LIGHTER W/NW WINDS LESS THAN 10 MPH...TURNING SW DURING THE
AFTERNOON.
LATEST SURFACE MAP SHOWS 1027 MB HIGH PRESSURE SPRAWLED FROM
NORTHERN MEXICO AND TEXAS AND RIDGING INTO WESTERN IL. MEANWHILE
ELONGATED 1001 MB LOW PRESSURE WAS ALONG THE NJ AND SOUTHERN NEW
ENGLAND COAST. UPPER LEVEL RIDGE OVER THE HIGH PLAINS WITH 500 MB
HEIGHTS RISING OVER IL TO 567 DM WHILE SHARP UPPER LEVEL TROF WAS
OVER THE ATLANTIC STATES. BROKEN TO OVERCAST STRATUS CLOUDS REMAIN
OVER MUCH OF CENTRAL AND SE IL THOUGH LARGE BREAKS FROM LINCOLN
NORTH AND AROUND DANVILLE. PILOT REPORT OVER CHAMPAIGN SHOULD
CLOUD DESK FAIRLY SHALLOW WITH BASE 1K FT AND TOP 1.8K FT SO 800
FEET THICK STRATUS DECK. STILL SOME LINGERING FOG OVER PARTS OF
CENTRAL IL MAINLY NORTH OF I-70 WITH VSBYS 1-3 MILES AND A FEW
SPOTS LIKE RANTOUL... GALESBURG AND MACOMB HAVING DENSE FOG.
STRATUS AND FOG IS FAIRLY SHALLOW BUT ALSO HAVE LOW SUN ANGLE FOR
LATE NOVEMBER. EXPECT STRATUS CLOUDS AND FOG TO DISSIPATE INTO
MIDDAY AS SKIES BECOME MOSTLY SUNNY DURING THIS AFTERNOON. 1027 MB
HIGH PRESSURE TO BE CENTERED OVER THE MID MS VALLEY OF WESTERN
KY/TN BY 00Z/6 PM WHILE 500 MB HEIGHTS RISE TO NEAR 570 DM OVER
CENTRAL IL EARLY THIS EVENING. THIS SHOULD HELP TO INCREASE AMOUNT
OF SUNSHINE DURING THE AFTERNOON AND BRING HIGHS IN THE LOWER 50S.
THIS IS CLOSE TO NORMAL HIGHS IN THE UPPER 40S CENTRAL IL AND
LOWER 50S IN SE IL FOR THIS DATE. NEARBY SURFACE HIGH PRESSURE
WILL ALSO KEEP LIGHTER WINDS TODAY WITH W/NW WINDS LESS THAN 10
MPH SHIFTING SW DURING THE AFTERNOON.
HUETTL
&&
.AVIATION...
ISSUED 1155 AM CST WED NOV 23 2011
STRATUS CLOUD DECKS AROUND 1K FT ALONG I-72 THAT WAS TRAPPED IN AN
INVERSION FROM NEARBY SURFACE HIGH PRESSURE WILL SCATTERED OUT
DURING EARLY AFTERNOON...WHILE LINGERING FOG GIVING MVFR
VISIBILITIES WILL LIFT TO VFR VSBYS DURING NEXT HOUR OR TWO.
STRATUS CLOUDS HAVE ALREADY SCATTERED OUT AT PIA AND BMI LATE THIS
MORNING. VFR CONDITIONS THEN EXPECTED FROM MID AFTERNOON THROUGH
THURSDAY...THOUGH LIGHT FOG POSSIBLE WITH MVFR VSBYS OF 4-5 MILES
FROM 08Z-14Z...POSSIBLY TIL 15Z/9 AM IN EASTERN IL AT CMI.
SCATTERED THIN CIRRUS CLOUDS TO ARRIVE LATER TONIGHT AND FRIDAY
FROM THE WEST. WESTERLY WINDS AROUND 5 KTS TO TURN SW DURING THE
AFTERNOON AND SSW TONIGHT. EXPECT SSW WINDS TO INCREASE BETWEEN
10-15 KTS AFTER 14Z/8 AM THU AND BE STRONGEST NEAR 15 KTS AT BMI.
1027 MB HIGH PRESSURE ELONGATED FROM TX TO WESTERN IL TO SETTLE
OVER THE MID MS VALLEY BY SUNSET AND BE OVER THE SOUTHEAST STATES
FRIDAY. MEANWHILE UPPER LEVEL RIDGE OVER THE HIGH PLAINS WILL
DRIFT EAST INTO IL BY SUNSET THU. INCREASING PRESSURE GRADIENT
DURING THURSDAY WILL CAUSE THE BREEZY SSW WINDS TO DEVELOP.
HUETTL
&&
.PREV DISCUSSION...
ISSUED 245 AM CST WED NOV 23 2011
LAST OF THE SHOWERS WITH THE RECENT SYSTEM MOVED OUT OF THE
NORTHEAST CWA A COUPLE HOURS AGO. LOW STRATUS DECK CONTINUES OVER
MUCH OF THE AREA...BUT A LARGE CLEAR AREA HAS BEEN MOVING
SOUTHEAST...AND IS CREEPING INTO THE FAR NORTHWEST.
THE PRIMARY CONCERN IN THE SHORT TERM IS WITH THE TIMING OF THIS
CLEARING AREA. IN THE LONGER TERM...THE COLD FRONT PASSAGE THIS
WEEKEND...AND THE POTENTIAL FOR LINGERING PRECIPITATION EARLY NEXT
WEEK...IS THE MAIN FOCUS.
SHORT TERM...TODAY THROUGH FRIDAY...
CURRENT EXTENT OF STRATUS DECK SEEMS TO LINE UP REASONABLY WELL WITH
THE RUC 950 MB HUMIDITY AND CONDENSATION PRESSURE DEFICIT ANALYSES.
THIS WOULD INDICATE ANY CLEARING ACROSS THE FAR WEST WOULD BE
SOMEWHAT TEMPORARY EARLY THIS MORNING...WITH THE CORE OF THE
STEADIER CLEARING TREND OVERSPREADING THE CENTRAL AND NORTHEAST CWA.
WILL KEEP THE WESTERN CWA FAIRLY CLOUDY UNTIL ABOUT MID
AFTERNOON...WHERE LOW LEVEL INVERSION DOES NOT REALLY BREAK UNTIL
AFTER MIDDAY...AND THUS HIGH TEMPERATURES IN THIS AREA WILL LIKELY
STRUGGLE TO REACH 50 DEGREES TODAY.
HIGH PRESSURE AXIS...CURRENTLY EXTENDING FROM TEXAS NORTHEAST TO
NEAR MINNEAPOLIS...WILL SHIFT EASTWARD THROUGH TONIGHT AND BE JUST
EAST OF OUR AREA THURSDAY MORNING. ONCE THE CURRENT CLOUDS FINALLY
LEAVE...MOSTLY CLEAR SKIES SHOULD PREVAIL THROUGH FRIDAY. WENT A FEW
DEGREES ABOVE MOS GUIDANCE FOR BOTH THANKSGIVING DAY AND FRIDAY.
FRIDAY SHOULD BE THE WARMEST DAY...AS GUSTY SOUTHWEST WINDS AND
PLENTY OF MIXING ALLOW TEMPERATURES TO RISE WELL INTO THE 60S OVER
THE ENTIRE AREA.
LONG TERM...SATURDAY THROUGH TUESDAY...
TIMING OF INCOMING COLD FRONT ON SATURDAY CONTINUES TO SLOW A BIT.
HAVE LIMITED POPS TO THE WESTERN CWA AFTER MIDNIGHT FRIDAY
NIGHT...BUT CONTINUED WITH LIKELIES EVERYWHERE ON SATURDAY. LATEST
INDICATIONS GENERALLY HAVE THE FRONT ITSELF EAST OF THE CWA BY LATE
SATURDAY EVENING.
MEDIUM RANGE MODELS STILL STRUGGLING SOME WITH THE DEEPENING OF THE
UPPER TROUGH LATER THIS WEEKEND. THE GFS AND ECMWF ARE FAIRLY
SIMILAR WITH CUTTING OFF A LOW IN THE TENNESSEE VALLEY SUNDAY
NIGHT...WHILE THE GEM FEATURES A MUCH MORE PROGRESSIVE FLOW AND CUTS
OFF A LOW OVER SOUTHERN TEXAS. THE CONSISTENCY AMONG THE MODELS THE
LAST FEW DAYS...ESPECIALLY THE ECMWF...HAS BEEN UNDERWHELMING...SO
AM NOT QUITE READY TO DRY THINGS OUT EARLY NEXT WEEK. WILL LARGELY
KEEP THINGS IN THE SLIGHT CHANCE CATEGORY...EXCEPT ACROSS THE
EASTERN CWA WHERE MORE OF THE CUTOFF LOW EFFECT IS POSSIBLE.
TEMPERATURES WILL BE COLD ENOUGH THAT RAIN OR SNOW WILL BE POSSIBLE
WITH ANY PRECIPITATION THAT DOES OCCUR.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* AREAS IFR/LIFR CIGS THIS MORNING.
* POTENTIAL FOR RETURN TO MVFR CONDITIONS AS LARGE AREA OF
ST/STRATOCU FM N TO NW TO W OF NORTHERN IL SLOWLY ADVECTS
EASTWARD.
TRS
//DISCUSSION...UPDATED 14Z...
AREA OF LOW STRATUS AND BR THAT HAD BEEN ADVECTING S FM FAR SE WI
TO FAR NE IL JUST N OF ORD AIRFIELD AT 14Z AND CONTINUING TO
SPREAD S TOWARD MDW. WITH BRIGHT SUNSHINE BEYOND THE ST AREAS
EXPECT EDGES TO START TO MIX OUT. MODEL FCST TEMP AND MOISTURE
PROFILES ALSO SHOW A SIGNIFICANT INCREASE IN DEW POINT DEPRESSIONS
AT THE BASE OF THE LOWERING SUBSIDENCE INVERSION WHICH IS VERIFIED
BY 12Z DVN RAOB WHICH SHOWED A SHALLOW BUT SIGNIFICANT DRY LATER
950-875 HPA WHICH WILL BE ADVECTED E ACROSS NORTHERN IL SO DO NOT
ANTICIPATE THE IFR/LIFR TO PERSIST TO MUCH BEYOND MID MORNING.
TRS
PREVIOUS DISCUSSION...UPDATED 12Z...
MAIN CONCERN THIS MORNING REMAINS LOW CLOUD/VIS POTENTIAL. AREA
OF 200-500 FT CIGS...ALONG WITH LOW VISIBILITIES...CONTINUES TO
SLOWLY EXPAND SOUTH INTO NORTHEAST IL WHILE AN AREA OF LOW MVFR
CIGS EXPANDS OVER LAKE MICHIGAN AND SOUTH INTO NORTHWEST INDIANA.
FORECAST SOUNDINGS AND MOISTURE FIELDS ALL SHOW DRYING OF THE LOW
LEVELS BY LATE MORNING/EARLY AFTERNOON. BEFORE THEN...TRENDS ARE
NOT THAT CLEAR AND HAVE ONCE AGAIN OPTED TO MAINTAIN THE TEMPO FOR
LOWER CIGS/VIS FOR A FEW HRS THIS MORNING AND IF THESE LOWER CIGS
DO MAKE IT INTO THE TERMINALS...THERE IS THE POSSIBILITY THAT THEY
COULD PERSIST LONGER THAN 16Z THOUGH THEY WOULD LIKELY BE LIFTING
INTO AT LEAST IFR BY THAT TIME. OVERALL CONFIDENCE REMAINS QUITE
LOW.
A RIDGE OF HIGH PRESSURE WILL MOVE ACROSS THE AREA LATER TODAY
INTO THIS EVENING WITH ADDITIONAL MVFR CIGS ACROSS WISCONSIN AND
IOWA...ON THE BACK SIDE OF THIS RIDGE...POTENTIALLY MOVING ACROSS
NORTHWEST IL LATER TONIGHT INTO THURSDAY MORNING AND FOR NOW HAVE
JUST MENTIONED SCATTERED LOW MVFR CLOUDS AS THESE TRENDS WILL NEED
TO BE MONITORED THROUGH THE DAY. WITH THE RIDGE MOVING EAST OF THE
AREA TONIGHT...FOG POTENTIAL LOOKS SOMEWHAT LIMITED AT THE
TERMINALS...BETTER CHANCES SOUTHEAST OF THE TERMINALS AND HAVE
ONLY INCLUDED LIGHT FOG/MIST AT RFD/DPA FOR NOW. CMS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MODERATE CONFIDENCE IN IFR/LIFR CIGS AT/VC ORD AND MDW MIXING
OUT BY LATE MORNING.
*HIGH CONFIDENCE LIGHT NW-W WINDS GRADUALLY BECOMING W-SW DURING
THE REST OF THE DAY.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY THROUGH TUESDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND
POSSIBLY A FEW SHSN. CMS
&&
.MARINE...
300 AM CST
WITH LOW PRESSURE QUICKLY SHIFTING EAST OF THE LAKE THIS MORNING AND
HIGH PRESSURE SLOWLY BUILDING EAST THROUGH THE UPPER MIDWEST...WINDS
HAVE BEEN DIMINISHING ACROSS THE LAKE. WINDS WILL CONTINUE TO
DIMINISH AS THIS HIGH SHIFTS EAST TODAY WITH A BRIEF PERIOD OF
LIGHTER FLOW. ALTHOUGH WITH THIS HIGH CONTINUING TO THE EAST
TONIGHT...A FAIRLY ACTIVE SURFACE PATTERN WILL BE IN PLACE TO THE
NORTHWEST OF THE GREAT LAKES. THIS WILL PROVIDE A STRENGTHENING
PRESSURE GRADIENT OVER THE LAKE WITH WINDS INCREASING ONCE AGAIN.
THIS INCREASE IN WINDS WILL INITIALLY OCCUR OVER THE NORTHERN HALF
OF THE LAKE BUT WITH WINDS EVENTUALLY INCREASING OVER THE SOUTHERN
HALF LAKE TONIGHT INTO THURSDAY. WITH THIS HIGH REMAINING TO THE
SOUTHEAST OF THE LAKE AND THIS ACTIVE SURFACE PATTERN TO THE
NORTHWEST...A PERIOD OF STRONG SOUTHERLY FLOW WILL BE IN PLACE
THROUGH THE END OF THE WORK WEEK. ALTHOUGH THIS WEATHER PATTERN WILL
SUPPORT STRENGTHENING WINDS INTO FRIDAY...A WARMER AIR MASS WILL
MOVE ACROSS THE LAKE. THIS COULD PROVIDE MORE STABLE CONDITIONS AND
THUS LIMIT THE AMOUNT OF STRONGER WINDS ALOFT TO REACH THE SURFACE
OF THE LAKE. HAVE KEPT WINDS JUST BELOW GALES THURSDAY NIGHT INTO
FRIDAY DUE TO THIS WARMER AIR...BUT WILL HAVE TO CONTINUE TO MONITOR
LATER GUIDANCE TO ASSESS THE POSSIBILITY OF THESE STRONGER WINDS
ALOFT TO REACH THE SURFACE OF THE LAKE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
951 AM CST WED NOV 23 2011
.DISCUSSION...
ISSUED 950 AM CST WED NOV 23 2011
WILL UPDATE THE FORECAST LATE THIS MORNING AS THE FOG LIFTS INTO
MIDDAY WITH SKIES BECOMING MOSTLY SUNNY THIS AFTERNOON. OTHERWISE
REST OF FORECAST LOOKS ON TRACK WITH HIGHS IN THE LOWER 50S AND
LIGHTER W/NW WINDS LESS THAN 10 MPH...TURNING SW DURING THE
AFTERNOON.
LATEST SURFACE MAP SHOWS 1027 MB HIGH PRESSURE SPRAWLED FROM
NORTHERN MEXICO AND TEXAS AND RIDGING INTO WESTERN IL. MEANWHILE
ELONGATED 1001 MB LOW PRESSURE WAS ALONG THE NJ AND SOUTHERN NEW
ENGLAND COAST. UPPER LEVEL RIDGE OVER THE HIGH PLAINS WITH 500 MB
HEIGHTS RISING OVER IL TO 567 DM WHILE SHARP UPPER LEVEL TROF WAS
OVER THE ATLANTIC STATES. BROKEN TO OVERCAST STRATUS CLOUDS REMAIN
OVER MUCH OF CENTRAL AND SE IL THOUGH LARGE BREAKS FROM LINCOLN
NORTH AND AROUND DANVILLE. PILOT REPORT OVER CHAMPAIGN SHOULD
CLOUD DESK FAIRLY SHALLOW WITH BASE 1K FT AND TOP 1.8K FT SO 800
FEET THICK STRATUS DECK. STILL SOME LINGERING FOG OVER PARTS OF
CENTRAL IL MAINLY NORTH OF I-70 WITH VSBYS 1-3 MILES AND A FEW
SPOTS LIKE RANTOUL... GALESBURG AND MACOMB HAVING DENSE FOG.
STRATUS AND FOG IS FAIRLY SHALLOW BUT ALSO HAVE LOW SUN ANGLE FOR
LATE NOVEMBER. EXPECT STRATUS CLOUDS AND FOG TO DISSIPATE INTO
MIDDAY AS SKIES BECOME MOSTLY SUNNY DURING THIS AFTERNOON. 1027 MB
HIGH PRESSURE TO BE CENTERED OVER THE MID MS VALLEY OF WESTERN
KY/TN BY 00Z/6 PM WHILE 500 MB HEIGHTS RISE TO NEAR 570 DM OVER
CENTRAL IL EARLY THIS EVENING. THIS SHOULD HELP TO INCREASE AMOUNT
OF SUNSHINE DURING THE AFTERNOON AND BRING HIGHS IN THE LOWER 50S.
THIS IS CLOSE TO NORMAL HIGHS IN THE UPPER 40S CENTRAL IL AND
LOWER 50S IN SE IL FOR THIS DATE. NEARBY SURFACE HIGH PRESSURE
WILL ALSO KEEP LIGHTER WINDS TODAY WITH W/NW WINDS LESS THAN 10
MPH SHIFTING SW DURING THE AFTERNOON.
HUETTL
&&
.AVIATION...
ISSUED 515 AM CST WED NOV 23 2011
MAIN FORECAST ISSUE WILL BE LOW CLOUDS AND FOG THIS MORNING.
SATELLITE IMAGES INDICATE BREAKS IN THE LOW CLOUD DECK...BUT THESE
ARE FILLING IN WITH FOG AND EVEN LOWER STRATUS/OBSCURATIONS DUE TO
RADIATIONAL COOLING. THIS WARRANTS A BROAD BRUSH APPROACH WITH IFR
TEMPO LIFR THROUGH 15Z...FOLLOWED BY SOME MVFR FOG FOR A COUPLE OF
HOURS. VFR CONDITIONS WILL THEN PREVAIL THROUGH THE DAY. HIGH
PRESSURE RIDGE JUST WEST OF IL WILL MOVE THROUGH THE AREA TODAY...
WITH LIGHT WINDS BECOMING SOUTHERLY 12Z THU. SOME CONCERN FOR FOG
REDEVELOPMENT AFTER 06Z THU...SO FOR NOW WILL INDICATE SOME TEMPO
5SM BR 08Z-12Z THU.
04
&&
.PREV DISCUSSION...
ISSUED 245 AM CST WED NOV 23 2011
LAST OF THE SHOWERS WITH THE RECENT SYSTEM MOVED OUT OF THE
NORTHEAST CWA A COUPLE HOURS AGO. LOW STRATUS DECK CONTINUES OVER
MUCH OF THE AREA...BUT A LARGE CLEAR AREA HAS BEEN MOVING
SOUTHEAST...AND IS CREEPING INTO THE FAR NORTHWEST.
THE PRIMARY CONCERN IN THE SHORT TERM IS WITH THE TIMING OF THIS
CLEARING AREA. IN THE LONGER TERM...THE COLD FRONT PASSAGE THIS
WEEKEND...AND THE POTENTIAL FOR LINGERING PRECIPITATION EARLY NEXT
WEEK...IS THE MAIN FOCUS.
SHORT TERM...TODAY THROUGH FRIDAY...
CURRENT EXTENT OF STRATUS DECK SEEMS TO LINE UP REASONABLY WELL WITH
THE RUC 950 MB HUMIDITY AND CONDENSATION PRESSURE DEFICIT ANALYSES.
THIS WOULD INDICATE ANY CLEARING ACROSS THE FAR WEST WOULD BE
SOMEWHAT TEMPORARY EARLY THIS MORNING...WITH THE CORE OF THE
STEADIER CLEARING TREND OVERSPREADING THE CENTRAL AND NORTHEAST CWA.
WILL KEEP THE WESTERN CWA FAIRLY CLOUDY UNTIL ABOUT MID
AFTERNOON...WHERE LOW LEVEL INVERSION DOES NOT REALLY BREAK UNTIL
AFTER MIDDAY...AND THUS HIGH TEMPERATURES IN THIS AREA WILL LIKELY
STRUGGLE TO REACH 50 DEGREES TODAY.
HIGH PRESSURE AXIS...CURRENTLY EXTENDING FROM TEXAS NORTHEAST TO
NEAR MINNEAPOLIS...WILL SHIFT EASTWARD THROUGH TONIGHT AND BE JUST
EAST OF OUR AREA THURSDAY MORNING. ONCE THE CURRENT CLOUDS FINALLY
LEAVE...MOSTLY CLEAR SKIES SHOULD PREVAIL THROUGH FRIDAY. WENT A FEW
DEGREES ABOVE MOS GUIDANCE FOR BOTH THANKSGIVING DAY AND FRIDAY.
FRIDAY SHOULD BE THE WARMEST DAY...AS GUSTY SOUTHWEST WINDS AND
PLENTY OF MIXING ALLOW TEMPERATURES TO RISE WELL INTO THE 60S OVER
THE ENTIRE AREA.
LONG TERM...SATURDAY THROUGH TUESDAY...
TIMING OF INCOMING COLD FRONT ON SATURDAY CONTINUES TO SLOW A BIT.
HAVE LIMITED POPS TO THE WESTERN CWA AFTER MIDNIGHT FRIDAY
NIGHT...BUT CONTINUED WITH LIKELIES EVERYWHERE ON SATURDAY. LATEST
INDICATIONS GENERALLY HAVE THE FRONT ITSELF EAST OF THE CWA BY LATE
SATURDAY EVENING.
MEDIUM RANGE MODELS STILL STRUGGLING SOME WITH THE DEEPENING OF THE
UPPER TROUGH LATER THIS WEEKEND. THE GFS AND ECMWF ARE FAIRLY
SIMILAR WITH CUTTING OFF A LOW IN THE TENNESSEE VALLEY SUNDAY
NIGHT...WHILE THE GEM FEATURES A MUCH MORE PROGRESSIVE FLOW AND CUTS
OFF A LOW OVER SOUTHERN TEXAS. THE CONSISTENCY AMONG THE MODELS THE
LAST FEW DAYS...ESPECIALLY THE ECMWF...HAS BEEN UNDERWHELMING...SO
AM NOT QUITE READY TO DRY THINGS OUT EARLY NEXT WEEK. WILL LARGELY
KEEP THINGS IN THE SLIGHT CHANCE CATEGORY...EXCEPT ACROSS THE
EASTERN CWA WHERE MORE OF THE CUTOFF LOW EFFECT IS POSSIBLE.
TEMPERATURES WILL BE COLD ENOUGH THAT RAIN OR SNOW WILL BE POSSIBLE
WITH ANY PRECIPITATION THAT DOES OCCUR.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
824 AM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* AREAS IFR/LIFR CIGS AND VSBYS THIS MORNING.
* POTENTIAL FOR RETURN TO MVFR CONDITIONS AS LARGE AREA OF
ST/STRATOCU FM N TO NW TO W OF NORTHERN IL SLOWLY ADVECTS
EASTWARD.
TRS
//DISCUSSION...UPDATED 14Z...
AREA OF LOW STRATUS AND BR THAT HAD BEEN ADVECTING S FM FAR SE WI
TO FAR NE IL JUST N OF ORD AIRFIELD AT 14Z AND CONTINUING TO
SPREAD S TOWARD MDW. WITH BRIGHT SUNSHINE BEYOND THE ST AREAS
EXPECT EDGES TO START TO MIX OUT. MODEL FCST TEMP AND MOISTURE
PROFILES ALSO SHOW A SIGNIFICANT INCREASE IN DEW POINT DEPRESSIONS
AT THE BASE OF THE LOWERING SUBSIDENCE INVERSION WHICH IS VERIFIED
BY 12Z DVN RAOB WHICH SHOWED A SHALLOW BUT SIGNIFICANT DRY LATER
950-875 HPA WHICH WILL BE ADVECTED E ACROSS NORTHERN IL SO DO NOT
ANTICIPATE THE IFR/LIFR TO PERSIST TO MUCH BEYOND MID MORNING.
TRS
PREVIOUS DISCUSSION...UPDATED 12Z...
MAIN CONCERN THIS MORNING REMAINS LOW CLOUD/VIS POTENTIAL. AREA
OF 200-500 FT CIGS...ALONG WITH LOW VISIBILITIES...CONTINUES TO
SLOWLY EXPAND SOUTH INTO NORTHEAST IL WHILE AN AREA OF LOW MVFR
CIGS EXPANDS OVER LAKE MICHIGAN AND SOUTH INTO NORTHWEST INDIANA.
FORECAST SOUNDINGS AND MOISTURE FIELDS ALL SHOW DRYING OF THE LOW
LEVELS BY LATE MORNING/EARLY AFTERNOON. BEFORE THEN...TRENDS ARE
NOT THAT CLEAR AND HAVE ONCE AGAIN OPTED TO MAINTAIN THE TEMPO FOR
LOWER CIGS/VIS FOR A FEW HRS THIS MORNING AND IF THESE LOWER CIGS
DO MAKE IT INTO THE TERMINALS...THERE IS THE POSSIBILITY THAT THEY
COULD PERSIST LONGER THAN 16Z THOUGH THEY WOULD LIKELY BE LIFTING
INTO AT LEAST IFR BY THAT TIME. OVERALL CONFIDENCE REMAINS QUITE
LOW.
A RIDGE OF HIGH PRESSURE WILL MOVE ACROSS THE AREA LATER TODAY
INTO THIS EVENING WITH ADDITIONAL MVFR CIGS ACROSS WISCONSIN AND
IOWA...ON THE BACK SIDE OF THIS RIDGE...POTENTIALLY MOVING ACROSS
NORTHWEST IL LATER TONIGHT INTO THURSDAY MORNING AND FOR NOW HAVE
JUST MENTIONED SCATTERED LOW MVFR CLOUDS AS THESE TRENDS WILL NEED
TO BE MONITORED THROUGH THE DAY. WITH THE RIDGE MOVING EAST OF THE
AREA TONIGHT...FOG POTENTIAL LOOKS SOMEWHAT LIMITED AT THE
TERMINALS...BETTER CHANCES SOUTHEAST OF THE TERMINALS AND HAVE
ONLY INCLUDED LIGHT FOG/MIST AT RFD/DPA FOR NOW. CMS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MODERATE CONFIDENCE IN IFR/LIFR CIGS VS ORD AND MDW THRU MID
MORNING THOUGH LOW CONFIDENCE IN ACTUALLY BECOMING PREVAILING
OVER THESE SITES.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY THROUGH TUESDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND
POSSIBLY A FEW SHSN. CMS
&&
.MARINE...
300 AM CST
WITH LOW PRESSURE QUICKLY SHIFTING EAST OF THE LAKE THIS MORNING AND
HIGH PRESSURE SLOWLY BUILDING EAST THROUGH THE UPPER MIDWEST...WINDS
HAVE BEEN DIMINISHING ACROSS THE LAKE. WINDS WILL CONTINUE TO
DIMINISH AS THIS HIGH SHIFTS EAST TODAY WITH A BRIEF PERIOD OF
LIGHTER FLOW. ALTHOUGH WITH THIS HIGH CONTINUING TO THE EAST
TONIGHT...A FAIRLY ACTIVE SURFACE PATTERN WILL BE IN PLACE TO THE
NORTHWEST OF THE GREAT LAKES. THIS WILL PROVIDE A STRENGTHENING
PRESSURE GRADIENT OVER THE LAKE WITH WINDS INCREASING ONCE AGAIN.
THIS INCREASE IN WINDS WILL INITIALLY OCCUR OVER THE NORTHERN HALF
OF THE LAKE BUT WITH WINDS EVENTUALLY INCREASING OVER THE SOUTHERN
HALF LAKE TONIGHT INTO THURSDAY. WITH THIS HIGH REMAINING TO THE
SOUTHEAST OF THE LAKE AND THIS ACTIVE SURFACE PATTERN TO THE
NORTHWEST...A PERIOD OF STRONG SOUTHERLY FLOW WILL BE IN PLACE
THROUGH THE END OF THE WORK WEEK. ALTHOUGH THIS WEATHER PATTERN WILL
SUPPORT STRENGTHENING WINDS INTO FRIDAY...A WARMER AIR MASS WILL
MOVE ACROSS THE LAKE. THIS COULD PROVIDE MORE STABLE CONDITIONS AND
THUS LIMIT THE AMOUNT OF STRONGER WINDS ALOFT TO REACH THE SURFACE
OF THE LAKE. HAVE KEPT WINDS JUST BELOW GALES THURSDAY NIGHT INTO
FRIDAY DUE TO THIS WARMER AIR...BUT WILL HAVE TO CONTINUE TO MONITOR
LATER GUIDANCE TO ASSESS THE POSSIBILITY OF THESE STRONGER WINDS
ALOFT TO REACH THE SURFACE OF THE LAKE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WILMETTE HARBOR TO MICHIGAN CITY IN UNTIL
9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
608 AM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* LIFR/VLIFR CIGS/VIS THIS MORNING. CMS
//DISCUSSION...UPDATED 12Z...
MAIN CONCERN THIS MORNING REMAINS LOW CLOUD/VIS POTENTIAL. AREA
OF 200-500 FT CIGS...ALONG WITH LOW VISIBILITIES...CONTINUES TO
SLOWLY EXPAND SOUTH INTO NORTHEAST IL WHILE AN AREA OF LOW MVFR
CIGS EXPANDS OVER LAKE MICHIGAN AND SOUTH INTO NORTHWEST INDIANA.
FORECAST SOUNDINGS AND MOISTURE FIELDS ALL SHOW DRYING OF THE LOW
LEVELS BY LATE MORNING/EARLY AFTERNOON. BEFORE THEN...TRENDS ARE
NOT THAT CLEAR AND HAVE ONCE AGAIN OPTED TO MAINTAIN THE TEMPO FOR
LOWER CIGS/VIS FOR A FEW HRS THIS MORNING AND IF THESE LOWER CIGS
DO MAKE IT INTO THE TERMINALS...THERE IS THE POSSIBILITY THAT THEY
COULD PERSIST LONGER THAN 16Z THOUGH THEY WOULD LIKELY BE LIFTING
INTO AT LEAST IFR BY THAT TIME. OVERALL CONFIDENCE REMAINS QUITE
LOW.
A RIDGE OF HIGH PRESSURE WILL MOVE ACROSS THE AREA LATER TODAY
INTO THIS EVENING WITH ADDITIONAL MVFR CIGS ACROSS WISCONSIN AND
IOWA...ON THE BACK SIDE OF THIS RIDGE...POTENTIALLY MOVING ACROSS
NORTHWEST IL LATER TONIGHT INTO THURSDAY MORNING AND FOR NOW HAVE
JUST MENTIONED SCATTERED LOW MVFR CLOUDS AS THESE TRENDS WILL NEED
TO BE MONITORED THROUGH THE DAY. WITH THE RIDGE MOVING EAST OF THE
AREA TONIGHT...FOG POTENTIAL LOOKS SOMEWHAT LIMITED AT THE
TERMINALS...BETTER CHANCES SOUTHEAST OF THE TERMINALS AND HAVE
ONLY INCLUDED LIGHT FOG/MIST AT RFD/DPA FOR NOW. CMS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* LOW CONFIDENCE REGARDING CIGS/VIS AND TIMING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY THROUGH TUESDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND
POSSIBLY A FEW SHSN. CMS
&&
.MARINE...
300 AM CST
WITH LOW PRESSURE QUICKLY SHIFTING EAST OF THE LAKE THIS MORNING AND
HIGH PRESSURE SLOWLY BUILDING EAST THROUGH THE UPPER MIDWEST...WINDS
HAVE BEEN DIMINISHING ACROSS THE LAKE. WINDS WILL CONTINUE TO
DIMINISH AS THIS HIGH SHIFTS EAST TODAY WITH A BRIEF PERIOD OF
LIGHTER FLOW. ALTHOUGH WITH THIS HIGH CONTINUING TO THE EAST
TONIGHT...A FAIRLY ACTIVE SURFACE PATTERN WILL BE IN PLACE TO THE
NORTHWEST OF THE GREAT LAKES. THIS WILL PROVIDE A STRENGTHENING
PRESSURE GRADIENT OVER THE LAKE WITH WINDS INCREASING ONCE AGAIN.
THIS INCREASE IN WINDS WILL INITIALLY OCCUR OVER THE NORTHERN HALF
OF THE LAKE BUT WITH WINDS EVENTUALLY INCREASING OVER THE SOUTHERN
HALF LAKE TONIGHT INTO THURSDAY. WITH THIS HIGH REMAINING TO THE
SOUTHEAST OF THE LAKE AND THIS ACTIVE SURFACE PATTERN TO THE
NORTHWEST...A PERIOD OF STRONG SOUTHERLY FLOW WILL BE IN PLACE
THROUGH THE END OF THE WORK WEEK. ALTHOUGH THIS WEATHER PATTERN WILL
SUPPORT STRENGTHENING WINDS INTO FRIDAY...A WARMER AIR MASS WILL
MOVE ACROSS THE LAKE. THIS COULD PROVIDE MORE STABLE CONDITIONS AND
THUS LIMIT THE AMOUNT OF STRONGER WINDS ALOFT TO REACH THE SURFACE
OF THE LAKE. HAVE KEPT WINDS JUST BELOW GALES THURSDAY NIGHT INTO
FRIDAY DUE TO THIS WARMER AIR...BUT WILL HAVE TO CONTINUE TO MONITOR
LATER GUIDANCE TO ASSESS THE POSSIBILITY OF THESE STRONGER WINDS
ALOFT TO REACH THE SURFACE OF THE LAKE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WILMETTE HARBOR TO MICHIGAN
CITY IN UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
515 AM CST WED NOV 23 2011
.DISCUSSION...
ISSUED 245 AM CST WED NOV 23 2011
LAST OF THE SHOWERS WITH THE RECENT SYSTEM MOVED OUT OF THE
NORTHEAST CWA A COUPLE HOURS AGO. LOW STRATUS DECK CONTINUES OVER
MUCH OF THE AREA...BUT A LARGE CLEAR AREA HAS BEEN MOVING
SOUTHEAST...AND IS CREEPING INTO THE FAR NORTHWEST.
THE PRIMARY CONCERN IN THE SHORT TERM IS WITH THE TIMING OF THIS
CLEARING AREA. IN THE LONGER TERM...THE COLD FRONT PASSAGE THIS
WEEKEND...AND THE POTENTIAL FOR LINGERING PRECIPITATION EARLY NEXT
WEEK...IS THE MAIN FOCUS.
SHORT TERM...TODAY THROUGH FRIDAY...
CURRENT EXTENT OF STRATUS DECK SEEMS TO LINE UP REASONABLY WELL WITH
THE RUC 950 MB HUMIDITY AND CONDENSATION PRESSURE DEFICIT ANALYSES.
THIS WOULD INDICATE ANY CLEARING ACROSS THE FAR WEST WOULD BE
SOMEWHAT TEMPORARY EARLY THIS MORNING...WITH THE CORE OF THE
STEADIER CLEARING TREND OVERSPREADING THE CENTRAL AND NORTHEAST CWA.
WILL KEEP THE WESTERN CWA FAIRLY CLOUDY UNTIL ABOUT MID
AFTERNOON...WHERE LOW LEVEL INVERSION DOES NOT REALLY BREAK UNTIL
AFTER MIDDAY...AND THUS HIGH TEMPERATURES IN THIS AREA WILL LIKELY
STRUGGLE TO REACH 50 DEGREES TODAY.
HIGH PRESSURE AXIS...CURRENTLY EXTENDING FROM TEXAS NORTHEAST TO
NEAR MINNEAPOLIS...WILL SHIFT EASTWARD THROUGH TONIGHT AND BE JUST
EAST OF OUR AREA THURSDAY MORNING. ONCE THE CURRENT CLOUDS FINALLY
LEAVE...MOSTLY CLEAR SKIES SHOULD PREVAIL THROUGH FRIDAY. WENT A FEW
DEGREES ABOVE MOS GUIDANCE FOR BOTH THANKSGIVING DAY AND FRIDAY.
FRIDAY SHOULD BE THE WARMEST DAY...AS GUSTY SOUTHWEST WINDS AND
PLENTY OF MIXING ALLOW TEMPERATURES TO RISE WELL INTO THE 60S OVER
THE ENTIRE AREA.
LONG TERM...SATURDAY THROUGH TUESDAY...
TIMING OF INCOMING COLD FRONT ON SATURDAY CONTINUES TO SLOW A BIT.
HAVE LIMITED POPS TO THE WESTERN CWA AFTER MIDNIGHT FRIDAY
NIGHT...BUT CONTINUED WITH LIKELIES EVERYWHERE ON SATURDAY. LATEST
INDICATIONS GENERALLY HAVE THE FRONT ITSELF EAST OF THE CWA BY LATE
SATURDAY EVENING.
MEDIUM RANGE MODELS STILL STRUGGLING SOME WITH THE DEEPENING OF THE
UPPER TROUGH LATER THIS WEEKEND. THE GFS AND ECMWF ARE FAIRLY
SIMILAR WITH CUTTING OFF A LOW IN THE TENNESSEE VALLEY SUNDAY
NIGHT...WHILE THE GEM FEATURES A MUCH MORE PROGRESSIVE FLOW AND CUTS
OFF A LOW OVER SOUTHERN TEXAS. THE CONSISTENCY AMONG THE MODELS THE
LAST FEW DAYS...ESPECIALLY THE ECMWF...HAS BEEN UNDERWHELMING...SO
AM NOT QUITE READY TO DRY THINGS OUT EARLY NEXT WEEK. WILL LARGELY
KEEP THINGS IN THE SLIGHT CHANCE CATEGORY...EXCEPT ACROSS THE
EASTERN CWA WHERE MORE OF THE CUTOFF LOW EFFECT IS POSSIBLE.
TEMPERATURES WILL BE COLD ENOUGH THAT RAIN OR SNOW WILL BE POSSIBLE
WITH ANY PRECIPITATION THAT DOES OCCUR.
GEELHART
&&
.AVIATION...
ISSUED 515 AM CST WED NOV 23 2011
MAIN FORECAST ISSUE WILL BE LOW CLOUDS AND FOG THIS MORNING.
SATELLITE IMAGES INDICATE BREAKS IN THE LOW CLOUD DECK...BUT THESE
ARE FILLING IN WITH FOG AND EVEN LOWER STRATUS/OBSCURATIONS DUE TO
RADIATIONAL COOLING. THIS WARRANTS A BROAD BRUSH APPROACH WITH IFR
TEMPO LIFR THROUGH 15Z...FOLLOWED BY SOME MVFR FOG FOR A COUPLE OF
HOURS. VFR CONDITIONS WILL THEN PREVAIL THROUGH THE DAY. HIGH
PRESSURE RIDGE JUST WEST OF IL WILL MOVE THROUGH THE AREA TODAY...
WITH LIGHT WINDS BECOMING SOUTHERLY 12Z THU. SOME CONCERN FOR FOG
REDEVELOPMENT AFTER 06Z THU...SO FOR NOW WILL INDICATE SOME TEMPO
5SM BR 08Z-12Z THU.
04
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
406 AM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 10Z...
* FOG/LOW CLOUD POTENTIAL THROUGH MID MORNING WITH LIFR/VLIFR
VIS/CIGS POSSIBLE. CMS
//DISCUSSION...UPDATED 10Z...
LOW CLOUDS AND FOG OVER EASTERN WI HAVE SLOWED THEIR PUSH SOUTH
BUT ARE NEARING THE WI/IL BORDER. WHAT APPEARS TO BE LOW CLOUDS
HAVE ALSO EXPANDED OVER THE WESTERN HALF OF LAKE MICHIGAN AND ARE
PUSHING SOUTH INTO NORTHWEST INDIANA. CONFIDENCE REGARDING TRENDS/
EXPECTATIONS THROUGH THE MORNING HRS IS RATHER LOW AND WITH THIS
UPDATE...OPTED TO JUST TWEAK TIMING AS THESE LOWER CONDITIONS MAY
STILL IMPACT SOME OF THE TERMINALS THIS MORNING. WITH DIMINISHING
WINDS AND VERY MOIST LOW LEVELS...COULD SEE ADDITIONAL LOW CIGS
AND LOWER VIS IN FOG DEVELOP ELSEWHERE. CMS
PREVIOUS 06Z DISCUSSION...
MAIN CONCERNS TONIGHT CONTINUE TO FOCUS ON POSSIBLE FOG DEVELOPMENT
ACROSS THE REGION.
A SURFACE RIDGE OF HIGH PRESSURE CURRENTLY BUILDING EAST ACROSS
IOWA...IS EXPECTED TO CONTINUE BUILDING EASTWARD ACROSS PORTIONS OF
NORTHERN ILLINOIS LATER TONIGHT. THE LATEST SATELLITE IMAGERY SHOWS
TONG OF CLEARING SKIES ACROSS EASTERN IOWA AND FAR NORTHWESTERN
ILLINOIS. VISIBILITIES ARE ALREADY BEGINNING TO TANK ACROSS THESE
AREAS AS FOG DEVELOPS. I AM EXPECTING THIS CLEARING LINE TO PROGRESS
EASTWARD OVER THE NEXT SEVERAL HOURS. A SIMPLE TIME OF ARRIVAL TOOL
IN AWIPS INDICATES THAT THIS CLEARING LINE SHOULD BE APPROACHING
KRFD AROUND 06 UTC AND THE NORTHEASTERN ILLINOIS TERMINALS AROUND 08
TO 09 UTC. THIS SHOULD HELP THE FOG DEVELOPMENT TO CONTINUE EASTWARD
ACROSS PORTIONS OF NORTHERN ILLINOIS AND SOUTHERN WISCONSIN. THE BIG
QUESTION MARK THAT REMAINS IS WILL THIS FOG MAKE IT ALL THE WAY TO
EAST TO KORD AND KMDW BY EARLY MORNING. UNCERTAINTIES REMAIN
REGARDING THE EASTWARD EXTENT OF THE FOG. HOWEVER...I WILL CONTINUE
TO MENTION THE POTENTIAL OF SOME IFR VISIBILITIES EARLY WEDNESDAY
MORNING ACROSS THE NORTHEASTERN ILLINOIS TERMINALS. THE AREA JUST
EXPERIENCED SOME RAINFALL AND DEW POINT DEPRESSIONS REMAIN LOW...SO
IT SHOULD NOT TAKE TO MUCH TO GET VISIBILITIES TO DROP.
ANY FOG THAT DOES DEVELOP MAY BE SLOW TO BURN OFF WEDNESDAY MORNING
WITH LIMITED ATMOSPHERIC MIXING. THEREFORE...SOME LOWER VISIBILITIES
MAY PERSIST THROUGH MID MORNING. CONDITIONS WILL IMPROVE DURING THE
AFTERNOON WITH LIGHT SOUTHWESTERLY FLOW AND VFR CONDITIONS EXPECTED.
HOWEVER...IT APPEARS THAT MORE FOG DEVELOPMENT MAY OCCUR AGAIN LATER
WEDNESDAY NIGHT AS WIND REMAIN LIGHT AND LOW LEVEL MOISTURE REMAINS
ELEVATED. THIS WILL HAVE TO BE WATCHED FOR POSSIBLE INCLUSION IN
FUTURE TAF FORECASTS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 10Z...
* LOW CONFIDENCE REGARDING FOG/LOW CIGS DEVELOPING ACROSS ORD/MDW
THIS MORNING AND LOW CONFIDENCE ON TIMING AND SPECIFIC CIG/VIS
VALUES. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY AND MONDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND POSSIBLY
SHSN.
KJB
&&
.MARINE...
300 AM CST
WITH LOW PRESSURE QUICKLY SHIFTING EAST OF THE LAKE THIS MORNING AND
HIGH PRESSURE SLOWLY BUILDING EAST THROUGH THE UPPER MIDWEST...WINDS
HAVE BEEN DIMINISHING ACROSS THE LAKE. WINDS WILL CONTINUE TO
DIMINISH AS THIS HIGH SHIFTS EAST TODAY WITH A BRIEF PERIOD OF
LIGHTER FLOW. ALTHOUGH WITH THIS HIGH CONTINUING TO THE EAST
TONIGHT...A FAIRLY ACTIVE SURFACE PATTERN WILL BE IN PLACE TO THE
NORTHWEST OF THE GREAT LAKES. THIS WILL PROVIDE A STRENGTHENING
PRESSURE GRADIENT OVER THE LAKE WITH WINDS INCREASING ONCE AGAIN.
THIS INCREASE IN WINDS WILL INITIALLY OCCUR OVER THE NORTHERN HALF
OF THE LAKE BUT WITH WINDS EVENTUALLY INCREASING OVER THE SOUTHERN
HALF LAKE TONIGHT INTO THURSDAY. WITH THIS HIGH REMAINING TO THE
SOUTHEAST OF THE LAKE AND THIS ACTIVE SURFACE PATTERN TO THE
NORTHWEST...A PERIOD OF STRONG SOUTHERLY FLOW WILL BE IN PLACE
THROUGH THE END OF THE WORK WEEK. ALTHOUGH THIS WEATHER PATTERN WILL
SUPPORT STRENGTHENING WINDS INTO FRIDAY...A WARMER AIR MASS WILL
MOVE ACROSS THE LAKE. THIS COULD PROVIDE MORE STABLE CONDITIONS AND
THUS LIMIT THE AMOUNT OF STRONGER WINDS ALOFT TO REACH THE SURFACE
OF THE LAKE. HAVE KEPT WINDS JUST BELOW GALES THURSDAY NIGHT INTO
FRIDAY DUE TO THIS WARMER AIR...BUT WILL HAVE TO CONTINUE TO MONITOR
LATER GUIDANCE TO ASSESS THE POSSIBILITY OF THESE STRONGER WINDS
ALOFT TO REACH THE SURFACE OF THE LAKE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WILMETTE HARBOR TO MICHIGAN
CITY IN UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
341 AM CST WED NOV 23 2011
.DISCUSSION...
340 AM CST
AFTER A GLOOMY TUESDAY...GENERALLY TRANQUIL WEATHER WILL BE SEEN
FOR MUCH OF THE NEXT 60 HOURS TO THE JOY OF HOLIDAY TRAVELERS AND
SHOPPERS. THE CHALLENGES IN THE FORECAST FOR THE NEXT THREE DAYS
ARE STRATUS/FOG EARLY THIS MORNING AND AGAIN FOR THANKSGIVING
MORNING AND ITS ASSOCIATED IMPACTS ON TEMPERATURES. THEN THE FOCUS
TURNS TO THIS WEEKEND INTO EARLY NEXT WEEK WITH COOLER AIR AND
SNOW CHANCES.
SYNOPSIS...THE SYSTEM THAT BROUGHT THE RAIN YESTERDAY IS NOW
EXITING THE PICTURE ACROSS THE NORTHEAST. THE BACK END OF THE
PRIMARY CLOUD SHIELD WILL MOVE OUT OF THE CWA BY MID-MORNING.
LINGERING LOW-LEVEL MOISTURE UNDER A SUBSIDENCE INVERSION AND
INCOMING SURFACE RIDGING HAS ALLOWED FOR EXPANSIVE STRATUS FROM
MN/WESTERN WI SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY. IN
ADDITION...SOME STRATUS/FOG IS OOZING ITS WAY SOUTH ALONG THE WEST
SHORE OF LAKE MI. SIMILAR STRATUS MAY TRY TO DEVELOP UNTIL MID-
MORNING AS THE PRIMARY SYNOPTIC CLOUD SHIELD EXITS ACROSS
NORTHWEST IN. LIGHT FOG IS SEEN IN THE CLEAR AREAS...PRESUMABLY
NOT HAVING BECOME MUCH WORSE DUE TO A LIGHT WIND COMPONENT.
TODAY AND TONIGHT...THE STRATUS CREEPING INTO THE NORTHERN
CHICAGO METRO IS NOT HANDLED WELL BY MOST OF THE MODELS...WHICH
CAN BE EXPECTED WITH SUCH A SMALL SCALE FEATURE. THE RUC AND NAM
PROFILES FOR ORD...WHILE NOT FULLY SATURATING IN THE LOW
LAYERS...SHOW THE INVERSION VERY SLOW TO LIFT THIS MORNING. HAVE
KEPT THOSE CLOUDS THROUGH MUCH OF THE MORNING WITHIN THE
FORECAST...AS WELL AS ACCOUNTED FOR SOME SCATTERED/BROKEN CLOUDS
ACROSS NORTHWEST IN. OUTSIDE OF THESE AREAS...A MOSTLY SUNNY SKY
IS EXPECTED WITH THE MAIN STRATUS/STRATOCU REMAINING WEST AND
SOUTH OF THE AREA. HIGHS ARE EXPECTED AROUND FIVE TO SEVEN DEGREES
WARMER THAN YESTERDAY. THE CLOUDS...AS WELL AS SOME FOG...BECOME A
CONCERN FOR TONIGHT AS RETURN FLOW JUST ABOVE THE INVERSION WILL
HELP TO ADVECT WHAT IS LEFT OF THE CLOUDS TO OUR WEST. EVEN IF
NONE IS LEFT...THE NAM 925/950MB SURFACES POINT TOWARDS
SATURATION...AS DOES THE SPC 4KM WRF COLUMN CONDENSATE
PRODUCT...WHICH HAS HANDLED THE LOW CLOUDS THIS MORNING THE BEST
OF ANY SHORT TERM MODEL. SO HAVE INCREASED SKY COVER SOME TONIGHT
AS WELL AS ADD PATCHY FOG WHERE THE WINDS WILL BE THE
LIGHTEST...GENERALLY SOUTH AND SOUTHEAST OF CHICAGO.
THANKSGIVING AND FRIDAY...THE POSSIBILITY OF CLOUDS AND AT LEAST
THE INFERENCE OF MORE LIMITED MIXING HAS LED TO FORECAST HIGHS ON
THE HOLIDAY TO BE INCHED DOWN A COUPLE DEGREES. SEVERAL MODELS
HAVE SHOWN THAT TREND AS WELL. MIX DOWN FROM 950 MB /WHICH MAY
EVEN BE A LITTLE DEEP/ SUPPORTS TEMPERATURES IN THE MID 50S. THE
WINDS WILL STAY UP THU NIGHT KEEPING TEMPERATURES ABOUT TEN
DEGREES WARMER THAN TONIGHT. FRIDAY WILL BE BREEZY WITH THE LOW-
LEVEL THERMAL RIDGE OF 10C AT 925 MB OVERRIDING THE AREA. WHILE NO
LOWER CLOUDS ARE EXPECTED DURING THE DAY...CIRRUS IS PROBABLE
ESPECIALLY ACROSS FAR NORTHERN IL AS SHOWN BY SIMULATED WATER
VAPOR AND UPPER LEVEL RH FIELDS ON THE NAM. HAVE BLENDED MIXING TO
940 MB FROM THE NAM WITH THE GOING FORECAST AS WELL AS THE BIAS
CORRECTED GUIDANCE WHICH HAS DONE WELL DURING THE WARMER DAYS. FOR
SOME MORE THOUGHTS ON FRIDAY TEMPERATURES...SEE THE CLIMATE
DISCUSSION BELOW.
THIS WEEKEND AND EARLY NEXT WEEK...THE MODEL GUIDANCE CONTINUES TO
SHOW LARGE DIFFERENCES IN THE LONG RANGE...ESPECIALLY FROM RUN TO
RUN OF EACH OF THE MODELS. LOW PRESSURE IS EXPECTED TO MOVE EAST
NORTHEAST ACROSS THE GREAT LAKES DURING SATURDAY...DRAGGING A
CANADIAN AIR MASS SOUTH SOUTHEAST INTO THE MIDDLE OF THE COUNTRY
FLOODING OUR AREA SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT IS
STRONG AND THE MOISTURE RETURN AHEAD OF IT IS NARROW BUT FOCUSED
DURING SATURDAY. CAN ENVISION WITH SUCH A FEATURE AND ORIENTATION
THAT AREAS OF SHOWERS WILL BE STREAMING NORTH NORTHEAST ALONG AND
IMMEDIATELY AHEAD OF THE FRONTAL BOUNDARY. MUCH OF FRIDAY NIGHT
MAY NOT ACTUALLY SEE MUCH FOR RAIN HERE GIVEN STILL WELL AHEAD OF
THE FRONT...AND THE 23.00 EC CONTINUED THAT TREND. SO REALLY
BACKED OFF ON POPS PRIOR TO MIDNIGHT IN CHICAGO AND AREAS SOUTH.
HAVE HIGHEST POPS DURING THE DAY SATURDAY STILL. THE UPPER TROUGH
IS EXPECTED TO PROGRESS SOUTHEAST WITH THE UPPER JET...AND FOR
MOST OF THE PAST MODEL RUNS OF THE GFS/EC A CUTOFF IS EXPECTED.
THE TREND HAS BEEN FOR THIS TO HAPPEN IN THE OHIO/TN RIVER VALLEY
AREA EARLY NEXT WEEK...WITH SOME RETROGRADING/PROGRESSION TO THE
NNW. A CONTINUED ACTIVE NORTHERN STREAM JET MAY ALSO PROVIDE
ENERGY TO ENHANCE CLOUDS AND SHOWER CHANCES THROUGH THIS PERIOD.
HAVE CONTINUED TO PREFER A MODEL BLEND WITH THE GOING FORECAST FOR
MOST SENSIBLE WEATHER ELEMENTS...AND IN GENERAL THAT SOLUTION
LOOKS FINE. PROFILES BEGIN TO FAVOR A MIX OR JUST MORE SNOW
SHOWERS BY SUNDAY...AND THEN AGAIN TUESDAY. THERE ALSO IS SUPPORT
IN THE LOW-LEVEL LAPSE RATES/MOISTURE/CONVERGENCE FOR LAKE
ENHANCED SHOWERS INTO NORTHWEST IN ON SUNDAY AND SUNDAY EVENING
AND HAVE GONE ABOVE BLENDED POPS FOR THAT AREA. AT THIS TIME...IT
LOOKS TO BE MORE OF RAIN SHOWER/MIX IN NORTHWEST IN.
&&
.CLIMATE...
238 AM CST
WHILE THE GOING FORECAST IS COOLER FOR THANKSGIVING DAY...THE HIGH
TEMPERATURE FORECAST OF 55 FOR CHICAGO /ORD/ AND ROCKFORD WOULD
PLACE THIS AS THE NINTH WARMEST THANKSGIVING ON RECORD FOR BOTH
SITES. THOUGH FRIDAY IS BECOMING INCREASINGLY LIKELY TO SEE 60
REACHED IN THE FORECAST AREA /ESPECIALLY SOUTH OF I-80/...RECORD
HIGHS FOR LONG TERM CLIMATE SITES LOOK OUT OF REACH. THOSE RECORDS
FOR NOVEMBER 25TH ARE 65 IN 2008 FOR ORD...AND 64 IN 1915 FOR RFD.
INTERESTINGLY ENOUGH...LOOKING BACK AT THE TOP FOUR MATCHING LOW-
LEVEL ANALOGS FROM THE CIPS ANALOG PAGE COMPARED TO THE 60 HOUR
FORECAST FROM THE 23.00 GFS...THE HIGHS AT ORD AVERAGED 59 DEGREES
WHICH IS RIGHT AT THE GOING FORECAST. THAT IS 15 DEGREES ABOVE
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* FOG POTENTIAL THROUGH MID MORNING WITH LIFR/VLIFR VIS/CIGS. CMS
//DISCUSSION...UPDATED 08Z...
NO SIGNIFICANT CHANGES TO THE TAFS WITH THIS UPDATE. ATTENTION IS
ON AN AREA OF EXPANDING CIGS BETWEEN 200-500 FT ACROSS MUCH OF
EASTERN WI...WHICH IS SLOWLY EXPANDING AND MOVING SOUTH. IF IT
MAINTAINS ITS CURRENT SPEED...IT WOULD ARRIVE AFTER THE CURRENT
11Z START TIME IN THE TEMPO BUT IT COULD CONTINUE TO EXPAND. A
LATER ARRIVAL WOULD LIKELY LEAD TO ADDITIONAL LIFR/IFR CONDITIONS
FURTHER INTO THE MORNING HRS BUT NOT ENOUGH CONFIDENCE TO MAKE
LARGE CHANGES JUST YET. VISIBILITIES ALSO IN THE 1/2SM TO 2SM
RANGE. CMS
PREVIOUS 06Z DISCUSSION...
MAIN CONCERNS TONIGHT CONTINUE TO FOCUS ON POSSIBLE FOG DEVELOPMENT
ACROSS THE REGION.
A SURFACE RIDGE OF HIGH PRESSURE CURRENTLY BUILDING EAST ACROSS
IOWA...IS EXPECTED TO CONTINUE BUILDING EASTWARD ACROSS PORTIONS OF
NORTHERN ILLINOIS LATER TONIGHT. THE LATEST SATELLITE IMAGERY SHOWS
TONG OF CLEARING SKIES ACROSS EASTERN IOWA AND FAR NORTHWESTERN
ILLINOIS. VISIBILITIES ARE ALREADY BEGINNING TO TANK ACROSS THESE
AREAS AS FOG DEVELOPS. I AM EXPECTING THIS CLEARING LINE TO PROGRESS
EASTWARD OVER THE NEXT SEVERAL HOURS. A SIMPLE TIME OF ARRIVAL TOOL
IN AWIPS INDICATES THAT THIS CLEARING LINE SHOULD BE APPROACHING
KRFD AROUND 06 UTC AND THE NORTHEASTERN ILLINOIS TERMINALS AROUND 08
TO 09 UTC. THIS SHOULD HELP THE FOG DEVELOPMENT TO CONTINUE EASTWARD
ACROSS PORTIONS OF NORTHERN ILLINOIS AND SOUTHERN WISCONSIN. THE BIG
QUESTION MARK THAT REMAINS IS WILL THIS FOG MAKE IT ALL THE WAY TO
EAST TO KORD AND KMDW BY EARLY MORNING. UNCERTAINTIES REMAIN
REGARDING THE EASTWARD EXTENT OF THE FOG. HOWEVER...I WILL CONTINUE
TO MENTION THE POTENTIAL OF SOME IFR VISIBILITIES EARLY WEDNESDAY
MORNING ACROSS THE NORTHEASTERN ILLINOIS TERMINALS. THE AREA JUST
EXPERIENCED SOME RAINFALL AND DEW POINT DEPRESSIONS REMAIN LOW...SO
IT SHOULD NOT TAKE TO MUCH TO GET VISIBILITIES TO DROP.
ANY FOG THAT DOES DEVELOP MAY BE SLOW TO BURN OFF WEDNESDAY MORNING
WITH LIMITED ATMOSPHERIC MIXING. THEREFORE...SOME LOWER VISIBILITIES
MAY PERSIST THROUGH MID MORNING. CONDITIONS WILL IMPROVE DURING THE
AFTERNOON WITH LIGHT SOUTHWESTERLY FLOW AND VFR CONDITIONS EXPECTED.
HOWEVER...IT APPEARS THAT MORE FOG DEVELOPMENT MAY OCCUR AGAIN LATER
WEDNESDAY NIGHT AS WIND REMAIN LIGHT AND LOW LEVEL MOISTURE REMAINS
ELEVATED. THIS WILL HAVE TO BE WATCHED FOR POSSIBLE INCLUSION IN
FUTURE TAF FORECASTS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* MEDIUM CONFIDENCE REGARDING FOG/LOW CIGS DEVELOPING ACROSS
ORD/MDW THIS MORNING...LOW CONFIDENCE ON TIMING AND SPECIFIC
CIG/VIS VALUES. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...VFR. BREEZY WITH SOUTH WINDS GUSTING 20-25KTS.
SATURDAY...RAIN LIKELY. MVFR LIKELY WITH IFR POSSIBLE.
SUNDAY AND MONDAY...MVFR POSSIBLE WITH SCATTERED SHRA AND POSSIBLY
SHSN.
KJB
&&
.MARINE...
300 AM CST
WITH LOW PRESSURE QUICKLY SHIFTING EAST OF THE LAKE THIS MORNING AND
HIGH PRESSURE SLOWLY BUILDING EAST THROUGH THE UPPER MIDWEST...WINDS
HAVE BEEN DIMINISHING ACROSS THE LAKE. WINDS WILL CONTINUE TO
DIMINISH AS THIS HIGH SHIFTS EAST TODAY WITH A BRIEF PERIOD OF
LIGHTER FLOW. ALTHOUGH WITH THIS HIGH CONTINUING TO THE EAST
TONIGHT...A FAIRLY ACTIVE SURFACE PATTERN WILL BE IN PLACE TO THE
NORTHWEST OF THE GREAT LAKES. THIS WILL PROVIDE A STRENGTHENING
PRESSURE GRADIENT OVER THE LAKE WITH WINDS INCREASING ONCE AGAIN.
THIS INCREASE IN WINDS WILL INITIALLY OCCUR OVER THE NORTHERN HALF
OF THE LAKE BUT WITH WINDS EVENTUALLY INCREASING OVER THE SOUTHERN
HALF LAKE TONIGHT INTO THURSDAY. WITH THIS HIGH REMAINING TO THE
SOUTHEAST OF THE LAKE AND THIS ACTIVE SURFACE PATTERN TO THE
NORTHWEST...A PERIOD OF STRONG SOUTHERLY FLOW WILL BE IN PLACE
THROUGH THE END OF THE WORK WEEK. ALTHOUGH THIS WEATHER PATTERN WILL
SUPPORT STRENGTHENING WINDS INTO FRIDAY...A WARMER AIR MASS WILL
MOVE ACROSS THE LAKE. THIS COULD PROVIDE MORE STABLE CONDITIONS AND
THUS LIMIT THE AMOUNT OF STRONGER WINDS ALOFT TO REACH THE SURFACE
OF THE LAKE. HAVE KEPT WINDS JUST BELOW GALES THURSDAY NIGHT INTO
FRIDAY DUE TO THIS WARMER AIR...BUT WILL HAVE TO CONTINUE TO MONITOR
LATER GUIDANCE TO ASSESS THE POSSIBILITY OF THESE STRONGER WINDS
ALOFT TO REACH THE SURFACE OF THE LAKE.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
245 AM CST WED NOV 23 2011
.DISCUSSION...
ISSUED 245 AM CST WED NOV 23 2011
LAST OF THE SHOWERS WITH THE RECENT SYSTEM MOVED OUT OF THE
NORTHEAST CWA A COUPLE HOURS AGO. LOW STRATUS DECK CONTINUES OVER
MUCH OF THE AREA...BUT A LARGE CLEAR AREA HAS BEEN MOVING
SOUTHEAST...AND IS CREEPING INTO THE FAR NORTHWEST.
THE PRIMARY CONCERN IN THE SHORT TERM IS WITH THE TIMING OF THIS
CLEARING AREA. IN THE LONGER TERM...THE COLD FRONT PASSAGE THIS
WEEKEND...AND THE POTENTIAL FOR LINGERING PRECIPITATION EARLY NEXT
WEEK...IS THE MAIN FOCUS.
SHORT TERM...TODAY THROUGH FRIDAY...
CURRENT EXTENT OF STRATUS DECK SEEMS TO LINE UP REASONABLY WELL
WITH THE RUC 950 MB HUMIDITY AND CONDENSATION PRESSURE DEFICIT
ANALYSES. THIS WOULD INDICATE ANY CLEARING ACROSS THE FAR WEST
WOULD BE SOMEWHAT TEMPORARY EARLY THIS MORNING...WITH THE CORE OF
THE STEADIER CLEARING TREND OVERSPREADING THE CENTRAL AND
NORTHEAST CWA. WILL KEEP THE WESTERN CWA FAIRLY CLOUDY UNTIL ABOUT
MID AFTERNOON...WHERE LOW LEVEL INVERSION DOES NOT REALLY BREAK
UNTIL AFTER MIDDAY...AND THUS HIGH TEMPERATURES IN THIS AREA WILL
LIKELY STRUGGLE TO REACH 50 DEGREES TODAY.
HIGH PRESSURE AXIS...CURRENTLY EXTENDING FROM TEXAS NORTHEAST TO
NEAR MINNEAPOLIS...WILL SHIFT EASTWARD THROUGH TONIGHT AND BE JUST
EAST OF OUR AREA THURSDAY MORNING. ONCE THE CURRENT CLOUDS FINALLY
LEAVE...MOSTLY CLEAR SKIES SHOULD PREVAIL THROUGH FRIDAY. WENT A
FEW DEGREES ABOVE MOS GUIDANCE FOR BOTH THANKSGIVING DAY AND
FRIDAY. FRIDAY SHOULD BE THE WARMEST DAY...AS GUSTY SOUTHWEST
WINDS AND PLENTY OF MIXING ALLOW TEMPERATURES TO RISE WELL INTO
THE 60S OVER THE ENTIRE AREA.
LONG TERM...SATURDAY THROUGH TUESDAY...
TIMING OF INCOMING COLD FRONT ON SATURDAY CONTINUES TO SLOW A BIT.
HAVE LIMITED POPS TO THE WESTERN CWA AFTER MIDNIGHT FRIDAY
NIGHT...BUT CONTINUED WITH LIKELIES EVERYWHERE ON SATURDAY. LATEST
INDICATIONS GENERALLY HAVE THE FRONT ITSELF EAST OF THE CWA BY
LATE SATURDAY EVENING.
MEDIUM RANGE MODELS STILL STRUGGLING SOME WITH THE DEEPENING OF
THE UPPER TROUGH LATER THIS WEEKEND. THE GFS AND ECMWF ARE FAIRLY
SIMILAR WITH CUTTING OFF A LOW IN THE TENNESSEE VALLEY SUNDAY
NIGHT...WHILE THE GEM FEATURES A MUCH MORE PROGRESSIVE FLOW AND
CUTS OFF A LOW OVER SOUTHERN TEXAS. THE CONSISTENCY AMONG THE
MODELS THE LAST FEW DAYS...ESPECIALLY THE ECMWF...HAS BEEN
UNDERWHELMING...SO AM NOT QUITE READY TO DRY THINGS OUT EARLY NEXT
WEEK. WILL LARGELY KEEP THINGS IN THE SLIGHT CHANCE CATEGORY...
EXCEPT ACROSS THE EASTERN CWA WHERE MORE OF THE CUTOFF LOW EFFECT
IS POSSIBLE. TEMPERATURES WILL BE COLD ENOUGH THAT RAIN OR SNOW
WILL BE POSSIBLE WITH ANY PRECIPITATION THAT DOES OCCUR.
GEELHART
&&
.AVIATION...
ISSUED 1120 PM CST TUE NOV 22 2011
STILL TRACKING THE CLEARING LINE SLOWLY MOVING SOUTHEAST INTO
NORTHWEST ILLINOIS FROM IOWA THIS EVENING. BASED ON SATELLITE
LOOP...THIS CLEARING LINE SHOULD REACH PIA AROUND 0915Z...SPI AND
BMI AROUND 1130Z...AND DEC AND CMI AFTER SUNRISE. SO THINKING IS
THAT PIA IS ONLY SITE THAT WILL SEE SIGNIFICANT FOG IN
MORNING...THOUGH NOT DENSE. SPI AND BMI WILL HAVE SOME FOG IN
MORNING...BUT NOT AS LOW AS PIA. DEC AND CMI WILL LIKELY NOT HAVE
ANY FOG IN MORNING. BELIEVE REST OF TAF PERIOD AT ALL SITES WILL
SEE SOME HIGH CIRRUS TO CLEAR TOMORROW NIGHT. SO IFR CIGS TO START
AT MOST LOCATIONS...EXCEPT FOR PIA...WHICH IS ALREADY MVFR. THEN
BECOMING VFR TOMORROW MORNING AND CONTINUING THROUGH TOMORROW
NIGHT. NORTHWEST WINDS WILL CONTINUE OVERNIGHT AND DECREASE IN
SPEED TIL MORNING. THEN LIGHT WEST DURING THE AFTERNOON AND
BECOMING LIGHT SOUTHWEST TOMORROW EVENING.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
756 PM EST THU NOV 24 2011
.UPDATE...
EVENING UPDATE SENT MAINLY TO ACCOUNT FOR SOME MINOR TWEAKS TO SKY
COVER. DIMINISHING LOW CLOUD TREND HAS REACHED NORTHERN SECTIONS
OF THE FORECAST AREA...ALTHOUGH CONFIDENCE IN DURATION OF THIS
CLEARING IS LOW. ALREADY BEGINNING TO SEE SOME SIGNS IN SATELLITE
IMAGERY OF NORTHWARD EXPANDING/ADVECTING STRATUS DECK FROM
SOUTHERN ILLINOIS INTO SOUTH CENTRAL INDIANA. LITTLE OVERALL
CHANGE NOTED IN THERMAL/MOISTURE PROFILES FROM THIS MORNING WITH
MAIN DIFFERENCE LATER TONIGHT BEING STRENGTHENING LOW LEVEL WARM
ADVECTION WITH INCREASING SOUTHWESTERLY FLOW TONIGHT. DIFFICULTY
IN FORECAST TONIGHT IS TRYING TO WEIGH COMPETING FACTORS FOR
STRATUS REDEVELOPMENT. LOW LEVEL WARM ADVECTION WILL LIKELY SERVE
TO ONLY SHARPEN AN ALREADY STRONG LOW LEVEL INVERSION THAT HAS
BEEN ABLE TO TRAP A THIN LAYER OF MOISTURE IN OVER THE PAST 24
HOURS. HOWEVER...THIS WARM ADVECTION MAY MAKE LOW LEVEL SATURATION
INCREASINGLY HARD TO COME BY LATER TONIGHT. BASED ON CURRENT
SATELLITE TRENDS TO THE SOUTH...WILL CONTINUE TO HEDGE THIS
FORECAST MORE TOWARD THE SIDE OF LOW CLOUD REDEVELOPMENT
OVERNIGHT. THIS IDEA ALSO GENERALLY SUPPORTED IN LOW LEVEL RH
PROGS FROM RUC/NAM. ONLY TWEAK TO FORECAST WAS TO DIMINISH SKY
COVER THIS EVENING...AND TO INDICATE INCREASING CLOUD TREND LATE
EVENING AND OVERNIGHT. IT STILL APPEARS AS THOUGH ANY LINGERING
LOW CLOUDS SHOULD FINALLY MIX OUT AND ERODE BY MID MORNING FRIDAY.
TEMPERATURES STILL LOOK TO BE ON TRACK WITH LIMITED DIURNAL RANGE
BASED ON EXPECTATION OF LOW CLOUD REDEVELOPMENT...WARM
ADVECTION...AND A MODEST SFC PRESSURE GRADIENT BEING MAINTAINED
OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 627 PM EST THU NOV 24 2011/
AVIATION...
00Z TAFS...MAIN AVIATION FORECAST QUESTION WILL CONTINUE TO CENTER
ON POTENTIAL OF IFR/MVFR CIGS TO REDEVELOP TONIGHT. CLEARING
TREND FROM SOUTH TO NORTH PER SATELLITE IMAGERY/SFC OBS NOTED LATE
AFTERNOON INTO EARLY EVENING...WITH RECENT KSBN OBSERVATIONS EVEN
SCATTERING MVFR DECK. DIURNAL COOLING AND PERSISTENCE OF AN
EXTREMELY STRONG LOW LEVEL INVERSION WILL ONCE AGAIN POSE THE
CONCERN OF STRATUS REDEVELOPMENT TONIGHT. ALREADY BEGINNING TO SEE
AREA OF STRATUS FROM SOUTHERN ILLINOIS INTO SOUTH CENTRAL INDIANA
SLOWLY BEGINNING TO CREEP BACK NORTHWARD AND WOULD SUSPECT THIS
TREND WILL CONTINUE THROUGH THE REMAINDER OF THE EVENING. AFTER
VFR CONDITIONS FOR SEVERAL HOURS THIS EVENING...DID MAINTAIN TREND
BACK TO HIGHER END IFR OR LOWER END MVFR CIGS FOR THE LATE
EVENING AND OVERNIGHT HOURS. MORE IMPRESSIVE LOW LEVEL FLOW AND
WARM ADVECTION ANTICIPATED BY MORNING WHICH SHOULD ALLOW FOR MORE
EFFICIENT MIXING OF THIS VERY THIN MOISTURE LAYER. FORECAST
CONFIDENCE IN THE ABOVE SCENARIO REGARDING STRATUS REDEVELOPMENT
REMAINS RELATIVELY LOW...BUT WITH LITTLE CHANGE IN
THERMAL/MOISTURE PROFILES...SEE NO REASON TO DEVIATE FROM
PESSIMISTIC TREND AT THIS TIME. WITH LOW CLOUDS ERODING...MIXING
SHOULD BE MORE EFFICIENT FRIDAY WITH SOUTH GUSTS TO 20 TO 25 KNOTS IN
THE LATE MORNING AND AFTERNOON.
&&
PREV DISCUSSION... /ISSUED 352 PM EST THU NOV 24 2011/
SHORT TERM...
TONIGHT THROUGH FRIDAY NIGHT
BROAD SW UPPER FLOW REMAINS IN PLACE OVER THE REGION WITH SFC
PRESSURE FALLS CONTINUING OVER THE UPPER MIDWEST IN RESPONSE TO A
PROGRESSING NORTHERN STREAM TROUGH. A STAUNCH INVERSION REMAINS IN
PLACE PER A SIG WAA REGIME...WITH TRAPPED MOISTURE IN THE BL.
INSOLATION AND ENSUED MIXING PROCESSES ARE WORKING TO BREAK THE
PERSISTENT CLOUD DECK UP...AND SOME SUN WILL BE POSSIBLE IN AREAS
THIS AFTERNOON. HOWEVER...DIURNAL BL COOLING WILL LIKELY SUPPORT
RE-SATURATION WITH THE CLOUD LAYER FILLING BACK IN...THIS BEING THE
MAIN FORECAST CHALLENGE. TEMPS HAVE STRUGGLED TO RISE ACROSS THE FA
GIVEN CLOUD COVER...BUT POSITIVE THERMAL ADVECTION HAS ALLOWED FOR
SOME RECOVERY AS LL WIND INCREASES PER HIGHER LATITUDE PRESSURE
FALLS. SYNOPTIC EVOLUTION IN THE PERIOD WILL FEATURE CENTRAL PLAINS
PHASING OF THE PAC NW AND SW CONUS UPPER TROUGHS...WITH A WAA REGIME
CONTINUING THROUGH THE PERIOD AHEAD OF THE LL TROUGH REFLECTION.
HEIGHT RISES COMBINED WITH A DIRTY TYPE RIDGE RIDDLED WITH LOW
AMPLITUDE IMPULSES WILL SUPPORT INCREASING CIRRUS ON FRIDAY. MUCH
WARMER WEATHER IS IN STORE FRIDAY GIVEN A TREND TO MOSTLY SUNNY
CONDITIONS AND WARM THERMAL FIELDS IN THE SFC TO H925 LAYER.
RAOB AND TAMDAR ANALYSIS CONFIRM A SATURATED LAYER IN THE
H975-H95 LAYER...WITH LOCAL CLOUD LAYER SOURCE BACK TRAJECTORY
SAMPLING A LARGE PORTION OF THE STRATUS LAYER IN PLACE OVER THE
LOWER MISSISSIPPI VALLEY. BULK OF DRY AIR PUSH ASSOCIATED WITH
REFLECTED LL FLOW WILL REMAIN NORTH OF THE REGION...WITH H975-H95
FLOW REMAINING SOUTHERLY OVERNIGHT. RUC13 AND NAM12 BOTH SUGGEST
RE-SATURATION OF THIS LAYER...WHICH IS VERY REASONABLE GIVEN CLOUD
LAYER TRAJECTORIES/A SHARP BL TOP INVERSION/AND AMPLE LL MOISTURE IN
THE BL. HENCE...EXPECTING CLOUDS TO FILL BACK IN THIS EVENING.
INCREASING NOCTURNAL LLJ AND ASSOCIATED TURBULENT MIX DOWN MAY
SUPPORT SOME CLOUD BREAK UP LATE IN THE NIGHT...ESP ACROSS THE
NORTHWEST WHERE H95 GEOSTROPHIC FLOW INCREASES TO OVER 35 KNOTS.
CLOUD LAYER FLOW WILL VEER SW TOWARD DAWN AND HELP SUPPORT THE
ADVECTION OF HIGH PLAINS SOURCE DRIER AIR...WITH CLEARING OF CIGS
THROUGH LATE MORNING. PHASING UPPER TROUGH WITH SLOW EAST ADVECTION
WILL DELAY ANY PRECIP CHANCES UNTIL SATURDAY GIVEN CONTINUED DRY
DEEP LAYER FLOW WITH THE BULK OF ALL SYSTEM GENERATED ASCENT
REMAINING WELL NORTH AND WEST OF THE REGION.
NO SIG CHANGE TO TEMPS. CLOUDS AND MIXED LL FLOW WILL SUPPORT A
RELATIVELY MILD NIGHT TONIGHT AND FRIDAY...WITH LOWS IN THE
40S...COOLEST READINGS TONIGHT. CLEARING LL STRATUS/WARM THERMAL
FIELDS/AND GENEROUS MIXING WILL SUPPORT HIGHS INTO THE 50S...WITH
SOME LOWER 60S POSSIBLE ACROSS THE SW THIRD FRIDAY.
&&
LONG TERM...
SATURDAY THROUGH THURSDAY. PRIMARY FOCUS ON DY3 PRECIP TIMING AND
INTRO RASN MIX LATE SAT NIGHT TO PRIMARY FZN PTYPE ON SUN...IN LES
REGN. LARGE DISCREPANCIES IN MID RANGE...HOWEVER FAVOR NAM/GFS/SREF
DVLPG GRTLKS CUTOFF DY3 AS OPPOSED TO ECMWF/GEM TAKING FAR SRN
DIXIE/GOMEX CUTOFF. GIVEN RAMPED NRN STREAM FLOW ACRS ENTIRE PACIFIC
TO JAPAN GTE 150 KTS PER SAT DERIVED WINDS...AIDED BY COMPLEX BC TO
ALEUTIANS VORTEX. STRONG/DEEP CAA IN MERIDONAL FLOW AS UL RIDGE FM
SOCAL BUILDS TOWARD SRN CANADA 12 UTC SUN. ADNLY NO ENSEMBLE GFS
MEMBERS TAKE STRONG SRN CUTOFF APPROACH. NAM/GFS BUFKIT WET BULB
PROFILES WOULD SUGGEST THAT PTYPE CHANGEOVER MAY BE COMPLETE TO FZN
ACRS NRN/NWRN CWA LATE SAT NIGHT...BUT GIVEN ALL LIQUID PRIOR FCST
WL ATTEMPT TO START TREND. SOME ACCUM PSBL IN LES REGN SUN...THOUGH
EXTRM DISCREPANCIES IN CBL FLOW AS EXPECTED AT F72-84. ATTENDENT SFC
LOW SHOULD BEGIN LIFTOUT MON WITH CONTINUATION OF PROGRESSIVE NRN
STREAM FLOW AND IN COLLAB WITH MI NEIGHBORS HAVE AXED PRIOR LOW CHC
MENTION MON-TUE NIGHT. FEW CHANGES OTHERWISE...APPEARS NEXT NRN
STREAM TROF DIGS INTO WRN GRTLKS/UPR MSVLY PER GEFS ON DY7 WITH
POTNL CHC SHSN THEREAFTER.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JC
LONG TERM...MURPHY
AVIATION...MARSILI
UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
627 PM EST THU NOV 24 2011
.AVIATION...
00Z TAFS...MAIN AVIATION FORECAST QUESTION WILL CONTINUE TO CENTER
ON POTENTIAL OF IFR/MVFR CIGS TO REDEVELOP TONIGHT. CLEARING
TREND FROM SOUTH TO NORTH PER SATELLITE IMAGERY/SFC OBS NOTED LATE
AFTERNOON INTO EARLY EVENING...WITH RECENT KSBN OBSERVATIONS EVEN
SCATTERING MVFR DECK. DIURNAL COOLING AND PRESISTENCE OF AN
EXTREMELY STRONG LOW LEVEL INVERSION WILL ONCE AGAIN POSE THE
CONCERN OF STRATUS REDEVELOPMENT TONIGHT. ALREADY BEGINNING TO SEE
AREA OF STRATUS FROM SOUTHERN ILLINOIS INTO SOUTH CENTRAL INDIANA
SLOWLY BEGINNING TO CREEP BACK NORTHWARD AND WOULD SUSPECT THIS
TREND WILL CONTINUE THROUGH THE REMAINDER OF THE EVENING. AFTER
VFR CONDITIONS FOR SEVERAL HOURS THIS EVENING...DID MAINTAIN TREND
BACK TO HIGHER END IFR OR LOWER END MVFR CIGS FOR THE LATE
EVENIGN AND OVERNIGHT HOURS. MORE IMPRESSIVE LOW LEVEL FLOW AND
WARM ADVECTION ANTICIPATED BY MORNING WHICH SHOULD ALLOW FOR MORE
EFFICIENT MIXING OF THIS VERY THIN MOISTURE LAYER. FORECAST
CONFIDENCE IN THE ABOVE SCENARIO REGARDING STRATUS REDEVELOPMENT
REMAINS RELATIVELY LOW...BUT WITH LITTLE CHANGE IN
THERMAL/MOISTURE PROFILES...SEE NO REASON TO DEVIATE FROM
PESSIMISSTIC TREND AT THIS TIME. WITH LOW CLOUDS ERODING...MIXING
SHOULD BE MORE EFFICIENT WEDNESDAY WITH SOUTH GUSTS TO 20 TO 25
KNOTS IN THE LATE MORNING AND AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 352 PM EST THU NOV 24 2011/
SHORT TERM...
TONIGHT THROUGH FRIDAY NIGHT
BROAD SW UPPER FLOW REMAINS IN PLACE OVER THE REGION WITH SFC
PRESSURE FALLS CONTINUING OVER THE UPPER MIDWEST IN RESPONSE TO A
PROGRESSING NORTHERN STREAM TROUGH. A STAUNCH INVERSION REMAINS IN
PLACE PER A SIG WAA REGIME...WITH TRAPPED MOISTURE IN THE BL.
INSOLATION AND ENSUED MIXING PROCESSES ARE WORKING TO BREAK THE
PERSISTENT CLOUD DECK UP...AND SOME SUN WILL BE POSSIBLE IN AREAS
THIS AFTERNOON. HOWEVER...DIURNAL BL COOLING WILL LIKELY SUPPORT
RE-SATURATION WITH THE CLOUD LAYER FILLING BACK IN...THIS BEING THE
MAIN FORECAST CHALLENGE. TEMPS HAVE STRUGGLED TO RISE ACROSS THE FA
GIVEN CLOUD COVER...BUT POSITIVE THERMAL ADVECTION HAS ALLOWED FOR
SOME RECOVERY AS LL WIND INCREASES PER HIGHER LATITUDE PRESSURE
FALLS. SYNOPTIC EVOLUTION IN THE PERIOD WILL FEATURE CENTRAL PLAINS
PHASING OF THE PAC NW AND SW CONUS UPPER TROUGHS...WITH A WAA REGIME
CONTINUING THROUGH THE PERIOD AHEAD OF THE LL TROUGH REFLECTION.
HEIGHT RISES COMBINED WITH A DIRTY TYPE RIDGE RIDDLED WITH LOW
AMPLITUDE IMPULSES WILL SUPPORT INCREASING CIRRUS ON FRIDAY. MUCH
WARMER WEATHER IS IN STORE FRIDAY GIVEN A TREND TO MOSTLY SUNNY
CONDITIONS AND WARM THERMAL FIELDS IN THE SFC TO H925 LAYER.
RAOB AND TAMDAR ANALYSIS CONFIRM A SATURATED LAYER IN THE
H975-H95 LAYER...WITH LOCAL CLOUD LAYER SOURCE BACK TRAJECTORY
SAMPLING A LARGE PORTION OF THE STRATUS LAYER IN PLACE OVER THE
LOWER MISSISSIPPI VALLEY. BULK OF DRY AIR PUSH ASSOCIATED WITH
REFLECTED LL FLOW WILL REMAIN NORTH OF THE REGION...WITH H975-H95
FLOW REMAINING SOUTHERLY OVERNIGHT. RUC13 AND NAM12 BOTH SUGGEST
RE-SATURATION OF THIS LAYER...WHICH IS VERY REASONABLE GIVEN CLOUD
LAYER TRAJECTORIES/A SHARP BL TOP INVERSION/AND AMPLE LL MOISTURE IN
THE BL. HENCE...EXPECTING CLOUDS TO FILL BACK IN THIS EVENING.
INCREASING NOCTURNAL LLJ AND ASSOCIATED TURBULENT MIX DOWN MAY
SUPPORT SOME CLOUD BREAK UP LATE IN THE NIGHT...ESP ACROSS THE
NORTHWEST WHERE H95 GEOSTROPHIC FLOW INCREASES TO OVER 35 KNOTS.
CLOUD LAYER FLOW WILL VEER SW TOWARD DAWN AND HELP SUPPORT THE
ADVECTION OF HIGH PLAINS SOURCE DRIER AIR...WITH CLEARING OF CIGS
THROUGH LATE MORNING. PHASING UPPER TROUGH WITH SLOW EAST ADVECTION
WILL DELAY ANY PRECIP CHANCES UNTIL SATURDAY GIVEN CONTINUED DRY
DEEP LAYER FLOW WITH THE BULK OF ALL SYSTEM GENERATED ASCENT
REMAINING WELL NORTH AND WEST OF THE REGION.
NO SIG CHANGE TO TEMPS. CLOUDS AND MIXED LL FLOW WILL SUPPORT A
RELATIVELY MILD NIGHT TONIGHT AND FRIDAY...WITH LOWS IN THE
40S...COOLEST READINGS TONIGHT. CLEARING LL STRATUS/WARM THERMAL
FIELDS/AND GENEROUS MIXING WILL SUPPORT HIGHS INTO THE 50S...WITH
SOME LOWER 60S POSSIBLE ACROSS THE SW THIRD FRIDAY.
&&
LONG TERM...
SATURDAY THROUGH THURSDAY. PRIMARY FOCUS ON DY3 PRECIP TIMING AND
INTRO RASN MIX LATE SAT NIGHT TO PRIMARY FZN PTYPE ON SUN...IN LES
REGN. LARGE DISCREPANCIES IN MID RANGE...HOWEVER FAVOR NAM/GFS/SREF
DVLPG GRTLKS CUTOFF DY3 AS OPPOSED TO ECMWF/GEM TAKING FAR SRN
DIXIE/GOMEX CUTOFF. GIVEN RAMPED NRN STREAM FLOW ACRS ENTIRE PACIFIC
TO JAPAN GTE 150 KTS PER SAT DERIVED WINDS...AIDED BY COMPLEX BC TO
ALEUTIANS VORTEX. STRONG/DEEP CAA IN MERIDONAL FLOW AS UL RIDGE FM
SOCAL BUILDS TOWARD SRN CANADA 12 UTC SUN. ADNLY NO ENSEMBLE GFS
MEMBERS TAKE STRONG SRN CUTOFF APPROACH. NAM/GFS BUFKIT WET BULB
PROFILES WOULD SUGGEST THAT PTYPE CHANGEOVER MAY BE COMPLETE TO FZN
ACRS NRN/NWRN CWA LATE SAT NIGHT...BUT GIVEN ALL LIQUID PRIOR FCST
WL ATTEMPT TO START TREND. SOME ACCUM PSBL IN LES REGN SUN...THOUGH
EXTRM DISCREPANCIES IN CBL FLOW AS EXPECTED AT F72-84. ATTENDENT SFC
LOW SHOULD BEGIN LIFTOUT MON WITH CONTINUATION OF PROGRESSIVE NRN
STREAM FLOW AND IN COLLAB WITH MI NEIGHBORS HAVE AXED PRIOR LOW CHC
MENTION MON-TUE NIGHT. FEW CHANGES OTHERWISE...APPEARS NEXT NRN
STREAM TROF DIGS INTO WRN GRTLKS/UPR MSVLY PER GEFS ON DY7 WITH
POTNL CHC SHSN THEREAFTER.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JC
LONG TERM...MURPHY
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
336 PM EST WED NOV 23 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE DRY AND MILD CONDITIONS FOR THE FIRST
PART OF THE LONG HOLIDAY WEEKEND...BEFORE A COLD FRONT BRINGS RAIN
AND COLDER TEMPERATURES FOR THE LATTER HALF. ANOTHER COLD FRONT
WILL MOVE THROUGH EARLY NEXT WEEK...REINFORCING THE COLDER AIR.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
FOCUS IS ON SKY AND POTENTIAL FOG. MODELS ARE SIMILAR SO A BLEND
IS OK.
VERY STUBBORN STRATUS DECK IS BEGINNING TO ERODE FROM THE WEST AND
THE EAST OF CENTRAL INDIANA THIS AFTERNOON...LEAVING MUCH OF
CENTRAL INDIANA CLOUDY. THIS SLOW CLEARING TREND WILL
CONTINUE INTO EARLY THIS EVENING...WITH CLOUDS REMAINING LONGEST
ACROSS SOUTHERN SECTIONS OF THE AREA.
THE PASSAGE OF THE 850MB RIDGE SHOULD HELP CLEAR THINGS OUT THIS
EVENING...BUT THEN CLEAR SKIES AND LIGHT WINDS WILL ALLOW PATCHY
FOG TO FORM...ESPECIALLY ACROSS THE SOUTH WHERE LITTLE IF ANY SUN
WAS SEEN TODAY. THUS HAVE ADDED PATCHY FOG ALL AREAS OVERNIGHT.
BUFKIT SUGGESTS THAT A STRATUS DECK MAY ALSO FORM...BUT NOT
CONFIDENT ABOUT THAT.
GENERALLY STUCK CLOSE TO A BLEND OF MOS FOR LOWS.
&&
.SHORT TERM /THANKSGIVING THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR RAIN SATURDAY. MODELS ARE IN DECENT
AGREEMENT SO CONTINUED WITH A BLEND.
ANY FOG OR STRATUS SHOULD BURN OFF EARLY THANKSGIVING AS HIGH
PRESSURE MOVES OFF TO THE EAST AND SOUTHWEST WINDS PICK UP. THE
SUNSHINE AND SOME WARM ADVECTION WILL ALLOW TEMPERATURES TO GET
ABOVE NORMAL IN THE MID AND UPPER 50S.
THE HIGH WILL KEEP MOSTLY CLEAR SKIES THURSDAY NIGHT AND FRIDAY
WITH WARM ADVECTION KEEPING READINGS ABOVE NORMAL.
CLOUDS WILL INCREASE FRIDAY NIGHT AHEAD OF AN APPROACHING COLD
FRONT. ALL MODELS HAVE SPED UP THE FRONT. THE RELATIVELY STRONG
FRONT ALONG WITH THE SHARP UPPER TROUGH SHOULD PROVIDE ENOUGH
FORCING FOR LIKELY POPS ACROSS THE WEST HALF OF THE AREA AND HIGH
CHANCE POPS EAST...MAINLY DURING SATURDAY AFTERNOON. INSTABILITY
IS LACKING SO LEFT OUT THUNDER MENTION.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GFS DEPICTS A WET AND COLDER PATTERN TAKING SHAPE THROUGH EARLY
NEXT WEEK AS SEVERAL SYSTEMS LOOK TO IMPACT THE REGION DURING THIS
TIME FRAME. ONLY VEERS FROM ALL BLEND WERE TO INCREASE CLOUD COVER
WHEN STRONG SYSTEMS WERE MOVING THROUGH.
A STRONG COLD FRONT LOOKS TO PUSH THROUGH THE REGION ON SATURDAY
NIGHT AND PUSH AN AREA OF SHRA ACROSS THE FORECAST AREA/ 850MB
TEMPERATURES FALL TO LESS THAN -4C ON SUNDAY AS MUCH OF THE
FORECAST SOUNDINGS FALL BELOW 0C. THUS A FEW SHSN WILL BE ABLE TO
MIX IN. HOWEVER WITH THE WARM AND WET GROUND...LITTLE TO NO
ACCUMULATION IS EXPECTED.
COLD AIR REMAINS IN PLACE ACROSS THE AREA ON MONDAY AHEAD OF RIDGE
BUILDING ACROSS THE AREA. SOME INSTABILITY SHRA/SHSN WILL BE
POSSIBLE GIVEN THE DOME OF COLD AIR ACROSS THE REGION.
ANOTHER UPPER LOW DROPS OUT OF THE GREAT LAKES INTO OHIO ON
TUESDAY NIGHT AND WEDNESDAY...ONCE AGAIN BRINGING CHANCES FOR
PRECIP ALONG WITH ANOTHER SHOT OF COLD AS 850MB TEMPERATURES
FALL TO -8C BY 12Z WED.
&&
.AVIATION /DISCUSSION FOR THE 23/21Z IND TAF UPDATE/...
NO CHANGES NECESSARY. PREVIOUS DISCUSSION FOLLOWS.
MVFR CONDITIONS EXPECTED TO LINGER ACROSS THE TAF SITES THROUGH
THE AFTERNOON.
SATELLITE IMAGES CONTINUE TO SHOW PESKY SC LINGERING ACROSS MUCH
OF THE STATE. RUC SEEMS TO REPRESENT THE ONGOING SITUATION
BEST...KEEPING LOWER LEVEL RH/S GREATER THAN 80% ACROSS THE AREA
THROUGH MUCH OF THE AFTERNOON. FURTHERMORE...A LAKE MICHIGAN
ENHANCED BAND OF CLOUDS SEEMS TO BE IN PLACE STREAMING SOUTHEAST
ACROSS LAF AND IND. THUS WILL KEEP THE MVFR CIGS IN THE FORECAST
UNTIL LATER TONIGHT WHEN THE UPPER RIDGE IS FINALLY EXPECTED TO
SLIDE EAST OF CENTRAL INDIANA.
ANY CLEARING MAY RESULT IN QUICK LOWER LEVEL SATURATION AS A GOOD
RADIATION COOLING SITUATION SETS UP. HAVE INCLUDED MVFR FOG AT
THE MORE RURAL TAF SITES LATE TONIGHT.
HIGH PRESSURE RIDGE AND DRY AIR WILL REMAIN ACROSS THE AREA ON
THURSDAY. THUS AFTER ANY MORNING FOG MIXES OUT...A RETURN TO VFR
IS EXPECTED AT ALL TAF SITES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....PUMA
AVIATION...JP/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
232 PM EST WED NOV 23 2011
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN
UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE DRY AND MILD CONDITIONS FOR THE FIRST
PART OF THE LONG HOLIDAY WEEKEND...BEFORE A COLD FRONT BRINGS RAIN
AND COLDER TEMPERATURES FOR THE LATTER HALF. ANOTHER COLD FRONT
WILL MOVE THROUGH EARLY NEXT WEEK...REINFORCING THE COLDER AIR.
&&
.NEAR TERM /LATE THIS AFTERNOON AND TONIGHT/...
FOCUS IS ON SKY AND POTENTIAL FOG. MODELS ARE SIMILAR SO A BLEND
IS OK.
VERY STUBBORN STRATUS DECK IS BEGINNING TO ERODE FROM THE WEST AND
THE EAST OF CENTRAL INDIANA THIS AFTERNOON...LEAVING MUCH OF
CENTRAL INDIANA CLOUDY. THIS SLOW CLEARING TREND WILL
CONTINUE INTO EARLY THIS EVENING...WITH CLOUDS REMAINING LONGEST
ACROSS SOUTHERN SECTIONS OF THE AREA.
THE PASSAGE OF THE 850MB RIDGE SHOULD HELP CLEAR THINGS OUT THIS
EVENING...BUT THEN CLEAR SKIES AND LIGHT WINDS WILL ALLOW PATCHY
FOG TO FORM...ESPECIALLY ACROSS THE SOUTH WHERE LITTLE IF ANY SUN
WAS SEEN TODAY. THUS HAVE ADDED PATCHY FOG ALL AREAS OVERNIGHT.
BUFKIT SUGGESTS THAT A STRATUS DECK MAY ALSO FORM...BUT NOT
CONFIDENT ABOUT THAT.
GENERALLY STUCK CLOSE TO A BLEND OF MOS FOR LOWS.
&&
.SHORT TERM /THANKSGIVING THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR RAIN SATURDAY. MODELS ARE IN DECENT
AGREEMENT SO CONTINUED WITH A BLEND.
ANY FOG OR STRATUS SHOULD BURN OFF EARLY THANKSGIVING AS HIGH
PRESSURE MOVES OFF TO THE EAST AND SOUTHWEST WINDS PICK UP. THE
SUNSHINE AND SOME WARM ADVECTION WILL ALLOW TEMPERATURES TO GET
ABOVE NORMAL IN THE MID AND UPPER 50S.
THE HIGH WILL KEEP MOSTLY CLEAR SKIES THURSDAY NIGHT AND FRIDAY
WITH WARM ADVECTION KEEPING READINGS ABOVE NORMAL.
CLOUDS WILL INCREASE FRIDAY NIGHT AHEAD OF AN APPROACHING COLD
FRONT. ALL MODELS HAVE SPED UP THE FRONT. THE RELATIVELY STRONG
FRONT ALONG WITH THE SHARP UPPER TROUGH SHOULD PROVIDE ENOUGH
FORCING FOR LIKELY POPS ACROSS THE WEST HALF OF THE AREA AND HIGH
CHANCE POPS EAST...MAINLY DURING SATURDAY AFTERNOON. INSTABILITY
IS LACKING SO LEFT OUT THUNDER MENTION.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GFS DEPICTS A WET AND COLDER PATTERN TAKING SHAPE THROUGH EARLY
NEXT WEEK AS SEVERAL SYSTEMS LOOK TO IMPACT THE REGION DURING THIS
TIME FRAME. ONLY VEERS FROM ALL BLEND WERE TO INCREASE CLOUD COVER
WHEN STRONG SYSTEMS WERE MOVING THROUGH.
A STRONG COLD FRONT LOOKS TO PUSH THROUGH THE REGION ON SATURDAY
NIGHT AND PUSH AN AREA OF SHRA ACROSS THE FORECAST AREA/ 850MB
TEMPERATURES FALL TO LESS THAN -4C ON SUNDAY AS MUCH OF THE
FORECAST SOUNDINGS FALL BELOW 0C. THUS A FEW SHSN WILL BE ABLE TO
MIX IN. HOWEVER WITH THE WARM AND WET GROUND...LITTLE TO NO
ACCUMULATION IS EXPECTED.
COLD AIR REMAINS IN PLACE ACROSS THE AREA ON MONDAY AHEAD OF RIDGE
BUILDING ACROSS THE AREA. SOME INSTABILITY SHRA/SHSN WILL BE
POSSIBLE GIVEN THE DOME OF COLD AIR ACROSS THE REGION.
ANOTHER UPPER LOW DROPS OUT OF THE GREAT LAKES INTO OHIO ON
TUESDAY NIGHT AND WEDNESDAY...ONCE AGAIN BRINGING CHANCES FOR
PRECIP ALONG WITH ANOTHER SHOT OF COLD AS 850MB TEMPERATURES
FALL TO -8C BY 12Z WED.
&&
.AVIATION /DISCUSSION FOR THE 18Z TAFS/...
MVFR CONDITIONS EXPECTED TO LINGER ACROSS THE TAF SITES THROUGH
THE AFTERNOON.
SATELLITE IMAGES CONTINUE TO SHOW PESKY SC LINGERING ACROSS MUCH
OF THE STATE. RUC SEEMS TO REPRESENT THE ONGOING SITUATION
BEST...KEEPING LOWER LEVEL RH/S GREATER THAN 80% ACROSS THE AREA
THROUGH MUCH OF THE AFTERNOON. FURTHERMORE...A LAKE MICHIGAN
ENHANCED BAND OF CLOUDS SEEMS TO BE IN PLACE STREAMING SOUTHEAST
ACROSS LAF AND IND. THUS WILL KEEP THE MVFR CIGS IN THE FORECAST
UNTIL LATER TONIGHT WHEN THE UPPER RIDGE IS FINALLY EXPECTED TO
SLIDE EAST OF CENTRAL INDIANA.
ANY CLEARING MAY RESULT IN QUICK LOWER LEVEL SATURATION AS A GOOD
RADIATION COOLING SITUATION SETS UP. HAVE INCLUDED MVFR FOG AT
THE MORE RURAL TAF SITES LATE TONIGHT.
HIGH PRESSURE RIDGE AND DRY AIR WILL REMAIN ACROSS THE AREA ON
THURSDAY. THUS AFTER ANY MORNING FOG MIXES OUT...A RETURN TO VFR
IS EXPECTED AT ALL TAF SITES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....PUMA
AVIATION...JP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
202 PM EST WED NOV 23 2011
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN ACROSS THE OHIO VALLEY TODAY AND TONIGHT
RESULTING IN DRY CONDITIONS AND MODERATING TEMPERATURES THROUGH THE
FRIDAY NIGHT. AFTERNOON HIGHS IN THE LOWER 50S TODAY WILL WARM TO
NEAR 60 DEGREES ON THANKSGIVING AND THE LOWER AND MID 60S BY BLACK
FRIDAY. THEN...A COLD FRONT WILL MOVE THROUGH SATURDAY NIGHT
FOLLOWED BY A SLOW MOVING UPPER LEVEL LOW. THIS WILL RESULT IN
COLDER TEMPERATURES ALONG WITH SIGNIFICANT CLOUD COVER AND RAIN
CHANCES THROUGH TUESDAY. THERE COULD EVEN BE SOME WET SNOW MIXED IN
WITH ANY RAIN SHOWER MONDAY NIGHT AND TUESDAY. HIGHS IN THE UPPER
50S TO AROUND 60 SATURDAY WILL ONLY BE IN THE 40S SUNDAY THROUGH
TUESDAY.
&&
.NEAR TERM /REST OF TODAY/...
STUBBORN STRATUS LOOKS TO LINGER THROUGH MUCH OF THE AFTERNOON OR
EVEN INTO THE EVENING ACROSS PARTS OF THE AREA. THUS HAVE UPDATED TO
INCREASE CLOUD COVER AND TWEAK DOWN TEMPERATURES...WHICH MAY BE
STILL TOO HIGH IF NO SUNSHINE CAN BREAK THROUGH THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
IT WILL BE A BENIGN SHORT TERM PERIOD WITH HIGH PRESSURE ANCHORED
OVER CENTRAL INDIANA. THE ONLY FOCUS REALLY WILL BE TEMPS AND
BREEZY SOUTHWEST WINDS ON FRIDAY.
MODELS ARE CONSISTENT WITH TONIGHT/S LOW TEMPS...BUT STILL HAVING A
TOUGH TIME BELIEVING THEY/RE ONLY GOING TO BOTTOM OUT IN THE MID
TO UPPER 30S WITH THE CLEAR SKIES. SO...TRENDED MUCH LOWER WITH
READINGS IN THE LOW TO MID 30S. TOMORROW...MODELS DIFFER QUITE A
BIT WITH THE GFS FAVORING WARM AIR...AND THE NAM GOING MUCH
COOLER. CURRENT THINKING IS THAT THE GFS IS HANDLING THE PATTERN
BETTER. WINDS WILL COME AROUND TO THE SOUTHWEST...ADVECTING SOME
WARMER AIR...AND SKIES WILL BE SUNNY. SO LEANED ON THE HIGH SIDE
WITH UPPER 50S/LOW 60S. TOMORROW NIGHT...SOUTHWESTERLY FLOW SHOULD
KEEP TEMPS FROM DROPPING DRASTICALLY...AND MODELS ARE IN GOOD
AGREEMENT WITH LOWS IN THE LOW 40S. BUT AGAIN...SOME CONCERN WITH
THEM FALLING BELOW THOSE NUMBERS WITH RADIATIONAL COOLING.
FRIDAY...NAM COMES INTO LINE WITH GFS AND STARTS PICKING UP ON
WARM SOUTHWEST FLOW. SO...WENT WITH A BLEND AND TOPPED HIGHS OFF
IN THE LOW 60S. PLUS...PRESSURE GRADIENT TIGHTENS AHEAD OF THE
NEXT SYSTEM...SO IT WILL BE BREEZY ON FRIDAY WITH SUSTAINED
SOUTHWEST WINDS OF 10 TO 20 MPH...ALSO AIDING IN WARM ADVECTION.
FRIDAY NIGHT...STUCK CLOSE TO GUIDANCE WITH LOWS GENERALLY IN THE
MID 40S. SOUTHWEST WINDS SHOULD PREVENT TEMPS FROM FALLING TOO
MUCH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GFS DEPICTS A WET AND COLDER PATTERN TAKING SHAPE THROUGH EARLY
NEXT WEEK AS SEVERAL SYSTEMS LOOK TO IMPACT THE REGION DURING THIS
TIME FRAME. ONLY VEERS FROM ALL BLEND WERE TO INCREASE CLOUD COVER
WHEN STRONG SYSTEMS WERE MOVING THROUGH.
A STRONG COLD FRONT LOOKS TO PUSH THROUGH THE REGION ON SATURDAY
NIGHT AND PUSH AN AREA OF SHRA ACROSS THE FORECAST AREA/ 850MB
TEMPERATURES FALL TO LESS THAN -4C ON SUNDAY AS MUCH OF THE
FORECAST SOUNDINGS FALL BELOW 0C. THUS A FEW SHSN WILL BE ABLE TO
MIX IN. HOWEVER WITH THE WARM AND WET GROUND...LITTLE TO NO
ACCUMULATION IS EXPECTED.
COLD AIR REMAINS IN PLACE ACROSS THE AREA ON MONDAY AHEAD OF RIDGE
BUILDING ACROSS THE AREA. SOME INSTABILITY SHRA/SHSN WILL BE
POSSIBLE GIVEN THE DOME OF COLD AIR ACROSS THE REGION.
ANOTHER UPPER LOW DROPS OUT OF THE GREAT LAKES INTO OHIO ON
TUESDAY NIGHT AND WEDNESDAY...ONCE AGAIN BRINGING CHANCES FOR
PRECIP ALONG WITH ANOTHER SHOT OF COLD AS 850MB TEMPERATURES
FALL TO -8C BY 12Z WED.
&&
.AVIATION /DISCUSSION FOR THE 18Z TAFS/...
MVFR CONDITIONS EXPECTED TO LINGER ACROSS THE TAF SITES THROUGH
THE AFTERNOON.
SATELLITE IMAGES CONTINUE TO SHOW PESKY SC LINGERING ACROSS MUCH
OF THE STATE. RUC SEEMS TO REPRESENT THE ONGOING SITUATION
BEST...KEEPING LOWER LEVEL RH/S GREATER THAN 80% ACROSS THE AREA
THROUGH MUCH OF THE AFTERNOON. FURTHERMORE...A LAKE MICHIGAN
ENHANCED BAND OF CLOUDS SEEMS TO BE IN PLACE STREAMING SOUTHEAST
ACROSS LAF AND IND. THUS WILL KEEP THE MVFR CIGS IN THE FORECAST
UNTIL LATER TONIGHT WHEN THE UPPER RIDGE IS FINALLY EXPECTED TO
SLIDE EAST OF CENTRAL INDIANA.
ANY CLEARING MAY RESULT IN QUICK LOWER LEVEL SATURATION AS A GOOD
RADIATION COOLING SITUATION SETS UP. HAVE INCLUDED MVFR FOG AT
THE MORE RURAL TAF SITES LATE TONIGHT.
HIGH PRESSURE RIDGE AND DRY AIR WILL REMAIN ACROSS THE AREA ON
THURSDAY. THUS AFTER ANY MORNING FOG MIXES OUT...A RETURN TO VFR
IS EXPECTED AT ALL TAF SITES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...50
SHORT TERM...TDUD
LONG TERM....PUMA
AVIATION...JP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1229 PM EST WED NOV 23 2011
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN ACROSS THE OHIO VALLEY TODAY AND TONIGHT
RESULTING IN DRY CONDITIONS AND MODERATING TEMPERATURES THROUGH THE
FRIDAY NIGHT. AFTERNOON HIGHS IN THE LOWER 50S TODAY WILL WARM TO
NEAR 60 DEGREES ON THANKSGIVING AND THE LOWER AND MID 60S BY BLACK
FRIDAY. THEN...A COLD FRONT WILL MOVE THROUGH SATURDAY NIGHT
FOLLOWED BY A SLOW MOVING UPPER LEVEL LOW. THIS WILL RESULT IN
COLDER TEMPERATURES ALONG WITH SIGNIFICANT CLOUD COVER AND RAIN
CHANCES THROUGH TUESDAY. THERE COULD EVEN BE SOME WET SNOW MIXED IN
WITH ANY RAIN SHOWER MONDAY NIGHT AND TUESDAY. HIGHS IN THE UPPER
50S TO AROUND 60 SATURDAY WILL ONLY BE IN THE 40S SUNDAY THROUGH
TUESDAY.
&&
.NEAR TERM /REST OF TODAY/...
STUBBORN STRATUS LOOKS TO LINGER THROUGH MUCH OF THE AFTERNOON OR
EVEN INTO THE EVENING ACROSS PARTS OF THE AREA. THUS HAVE UPDATED TO
INCREASE CLOUD COVER AND TWEAK DOWN TEMPERATURES...WHICH MAY BE
STILL TOO HIGH IF NO SUNSHINE CAN BREAK THROUGH THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
IT WILL BE A BENIGN SHORT TERM PERIOD WITH HIGH PRESSURE ANCHORED
OVER CENTRAL INDIANA. THE ONLY FOCUS REALLY WILL BE TEMPS AND
BREEZY SOUTHWEST WINDS ON FRIDAY.
MODELS ARE CONSISTENT WITH TONIGHT/S LOW TEMPS...BUT STILL HAVING A
TOUGH TIME BELIEVING THEY/RE ONLY GOING TO BOTTOM OUT IN THE MID
TO UPPER 30S WITH THE CLEAR SKIES. SO...TRENDED MUCH LOWER WITH
READINGS IN THE LOW TO MID 30S. TOMORROW...MODELS DIFFER QUITE A
BIT WITH THE GFS FAVORING WARM AIR...AND THE NAM GOING MUCH
COOLER. CURRENT THINKING IS THAT THE GFS IS HANDLING THE PATTERN
BETTER. WINDS WILL COME AROUND TO THE SOUTHWEST...ADVECTING SOME
WARMER AIR...AND SKIES WILL BE SUNNY. SO LEANED ON THE HIGH SIDE
WITH UPPER 50S/LOW 60S. TOMORROW NIGHT...SOUTHWESTERLY FLOW SHOULD
KEEP TEMPS FROM DROPPING DRASTICALLY...AND MODELS ARE IN GOOD
AGREEMENT WITH LOWS IN THE LOW 40S. BUT AGAIN...SOME CONCERN WITH
THEM FALLING BELOW THOSE NUMBERS WITH RADIATIONAL COOLING.
FRIDAY...NAM COMES INTO LINE WITH GFS AND STARTS PICKING UP ON
WARM SOUTHWEST FLOW. SO...WENT WITH A BLEND AND TOPPED HIGHS OFF
IN THE LOW 60S. PLUS...PRESSURE GRADIENT TIGHTENS AHEAD OF THE
NEXT SYSTEM...SO IT WILL BE BREEZY ON FRIDAY WITH SUSTAINED
SOUTHWEST WINDS OF 10 TO 20 MPH...ALSO AIDING IN WARM ADVECTION.
FRIDAY NIGHT...STUCK CLOSE TO GUIDANCE WITH LOWS GENERALLY IN THE
MID 40S. SOUTHWEST WINDS SHOULD PREVENT TEMPS FROM FALLING TOO
MUCH.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
EXPECT A WET PERIOD TO THE BULK OF THE EXTENDED. EXTENDED MODELS
CONTINUE TO COME TO A CONSENSUS WITH THE SPEED OF A COLD FRONT WITH
A GENERAL SLOWING TREND WHICH WOULD SEEM TO FAVOR THE SLOWER ECMWF
WHICH WOULD SUGGEST HIGH POPS ACROSS OUR WEST AND LOW CHANCE TO NO
POPS EAST WHICH IS CONSISTENT WITH THE CENTRAL REGION
INITIALIZATION...SO DID NOT MAKE ANY CHANGES THERE. RETURN FLOW
AHEAD OF THE FRONT SHOULD ALLOW TEMPERATURES TO BE WELL ABOVE NORMAL
ON SATURDAY WITH HIGHS 55 TO 60 PER INITIALIZATION LOOKING OK. THE
FRONT SHOULD BE THROUGH SHORTLY AFTER 12Z SUNDAY AT THE LATEST WITH
DECENT COLD AIR ADVECTION BEHIND IT. IN ADDITION...TRAILING
UPPER TROUGH AND ITS EVOLUTION RESULTING FROM A MERGER OF
NORTHWESTERN ENERGY ALONG WITH A SOUTHWESTERN TROUGH SHOULD KEEP
PLENTY OF CLOUDS AROUND AND PRECIPITATION CHANCES IN THROUGH
TUESDAY. THUS...NORMAL TO BELOW NORMAL TEMPERATURES WITH AFTERNOON
HIGHS MOSTLY IN THE 40S LOOK OK. ANY RAIN SHOWERS COULD MIX WITH
SNOW SHOWERS MONDAY NIGHT AND TUESDAY ESPECIALLY IF THE SLOWER ECMWF
TROUGH ALONG WITH ITS FURTHER NORTHWEST UPPER LOW VERIFY. OVER AN
INCH OF RAINFALL TOTAL LOOKS LIKE A GOOD BET OVER THE WEEKEND AND
EARLY NEXT WEEK. OVERALL...WITH LARGE MODEL DIFFERENCES...CONFIDENCE
IS NOT STRONG ENOUGH TO MAKE ANY CHANGES TO THE INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 18Z TAFS/...
MVFR CONDITIONS EXPECTED TO LINGER ACROSS THE TAF SITES THROUGH
THE AFTERNOON.
SATELLITE IMAGES CONTINUE TO SHOW PESKY SC LINGERING ACROSS MUCH
OF THE STATE. RUC SEEMS TO REPRESENT THE ONGOING SITUATION
BEST...KEEPING LOWER LEVEL RH/S GREATER THAN 80% ACROSS THE AREA
THROUGH MUCH OF THE AFTERNOON. FURTHERMORE...A LAKE MICHIGAN
ENHANCED BAND OF CLOUDS SEEMS TO BE IN PLACE STREAMING SOUTHEAST
ACROSS LAF AND IND. THUS WILL KEEP THE MVFR CIGS IN THE FORECAST
UNTIL LATER TONIGHT WHEN THE UPPER RIDGE IS FINALLY EXPECTED TO
SLIDE EAST OF CENTRAL INDIANA.
ANY CLEARING MAY RESULT IN QUICK LOWER LEVEL SATURATION AS A GOOD
RADIATION COOLING SITUATION SETS UP. HAVE INCLUDED MVFR FOG AT
THE MORE RURAL TAF SITES LATE TONIGHT.
HIGH PRESSURE RIDGE AND DRY AIR WILL REMAIN ACROSS THE AREA ON
THURSDAY. THUS AFTER ANY MORNING FOG MIXES OUT...A RETURN TO VFR
IS EXPECTED AT ALL TAF SITES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...50
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...JP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1204 PM EST WED NOV 23 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN ACROSS THE OHIO VALLEY TODAY AND TONIGHT
RESULTING IN DRY CONDITIONS AND MODERATING TEMPERATURES THROUGH THE
FRIDAY NIGHT. AFTERNOON HIGHS IN THE LOWER 50S TODAY WILL WARM TO
NEAR 60 DEGREES ON THANKSGIVING AND THE LOWER AND MID 60S BY BLACK
FRIDAY. THEN...A COLD FRONT WILL MOVE THROUGH SATURDAY NIGHT
FOLLOWED BY A SLOW MOVING UPPER LEVEL LOW. THIS WILL RESULT IN
COLDER TEMPERATURES ALONG WITH SIGNIFICANT CLOUD COVER AND RAIN
CHANCES THROUGH TUESDAY. THERE COULD EVEN BE SOME WET SNOW MIXED IN
WITH ANY RAIN SHOWER MONDAY NIGHT AND TUESDAY. HIGHS IN THE UPPER
50S TO AROUND 60 SATURDAY WILL ONLY BE IN THE 40S SUNDAY THROUGH
TUESDAY.
&&
.NEAR TERM /REST OF TODAY/...
STRATUS IS BEING STUBBORN AND STICKING AROUND LONGER ACROSS MUCH
OF THE AREA THAN PREVIOUSLY THOUGHT. PART OF THIS IS DUE TO
ENHANCEMENT FROM LAKE MICHIGAN. DRIER AIR WILL STILL WORK INTO
THE AREA TODAY SO STILL BELIEVE THAT STRATUS WILL EVENTUALLY BREAK
UP...BUT HAVE SLOWED DOWN CLEARING BY A FEW HOURS MOST AREAS.
THUS HAVE ALSO SLOWED DOWN THE TEMPERATURE RISE TODAY. HOWEVER
WITH SUNSHINE STILL EXPECTED THIS AFTERNOON...ONLY BUMPED DOWN
HIGHS A LITTLE FOR NOW. WILL KEEP AN EYE ON EVOLUTION OF THE CLOUD
DECK AND UPDATE AGAIN AS NECESSARY TODAY.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
IT WILL BE A BENIGN SHORT TERM PERIOD WITH HIGH PRESSURE ANCHORED
OVER CENTRAL INDIANA. THE ONLY FOCUS REALLY WILL BE TEMPS AND
BREEZY SOUTHWEST WINDS ON FRIDAY.
MODELS ARE CONSISTENT WITH TONIGHT/S LOW TEMPS...BUT STILL HAVING A
TOUGH TIME BELIEVING THEY/RE ONLY GOING TO BOTTOM OUT IN THE MID
TO UPPER 30S WITH THE CLEAR SKIES. SO...TRENDED MUCH LOWER WITH
READINGS IN THE LOW TO MID 30S. TOMORROW...MODELS DIFFER QUITE A
BIT WITH THE GFS FAVORING WARM AIR...AND THE NAM GOING MUCH
COOLER. CURRENT THINKING IS THAT THE GFS IS HANDLING THE PATTERN
BETTER. WINDS WILL COME AROUND TO THE SOUTHWEST...ADVECTING SOME
WARMER AIR...AND SKIES WILL BE SUNNY. SO LEANED ON THE HIGH SIDE
WITH UPPER 50S/LOW 60S. TOMORROW NIGHT...SOUTHWESTERLY FLOW SHOULD
KEEP TEMPS FROM DROPPING DRASTICALLY...AND MODELS ARE IN GOOD
AGREEMENT WITH LOWS IN THE LOW 40S. BUT AGAIN...SOME CONCERN WITH
THEM FALLING BELOW THOSE NUMBERS WITH RADIATIONAL COOLING.
FRIDAY...NAM COMES INTO LINE WITH GFS AND STARTS PICKING UP ON
WARM SOUTHWEST FLOW. SO...WENT WITH A BLEND AND TOPPED HIGHS OFF
IN THE LOW 60S. PLUS...PRESSURE GRADIENT TIGHTENS AHEAD OF THE
NEXT SYSTEM...SO IT WILL BE BREEZY ON FRIDAY WITH SUSTAINED
SOUTHWEST WINDS OF 10 TO 20 MPH...ALSO AIDING IN WARM ADVECTION.
FRIDAY NIGHT...STUCK CLOSE TO GUIDANCE WITH LOWS GENERALLY IN THE
MID 40S. SOUTHWEST WINDS SHOULD PREVENT TEMPS FROM FALLING TOO
MUCH.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
EXPECT A WET PERIOD TO THE BULK OF THE EXTENDED. EXTENDED MODELS
CONTINUE TO COME TO A CONSENSUS WITH THE SPEED OF A COLD FRONT WITH
A GENERAL SLOWING TREND WHICH WOULD SEEM TO FAVOR THE SLOWER ECMWF
WHICH WOULD SUGGEST HIGH POPS ACROSS OUR WEST AND LOW CHANCE TO NO
POPS EAST WHICH IS CONSISTENT WITH THE CENTRAL REGION
INITIALIZATION...SO DID NOT MAKE ANY CHANGES THERE. RETURN FLOW
AHEAD OF THE FRONT SHOULD ALLOW TEMPERATURES TO BE WELL ABOVE NORMAL
ON SATURDAY WITH HIGHS 55 TO 60 PER INITIALIZATION LOOKING OK. THE
FRONT SHOULD BE THROUGH SHORTLY AFTER 12Z SUNDAY AT THE LATEST WITH
DECENT COLD AIR ADVECTION BEHIND IT. IN ADDITION...TRAILING
UPPER TROUGH AND ITS EVOLUTION RESULTING FROM A MERGER OF
NORTHWESTERN ENERGY ALONG WITH A SOUTHWESTERN TROUGH SHOULD KEEP
PLENTY OF CLOUDS AROUND AND PRECIPITATION CHANCES IN THROUGH TUESDAY.
THUS...NORMAL TO BELOW NORMAL TEMPERATURES WITH AFTERNOON HIGHS
MOSTLY IN THE 40S LOOK OK. ANY RAIN SHOWERS COULD MIX WITH SNOW
SHOWERS MONDAY NIGHT AND TUESDAY ESPECIALLY IF THE SLOWER ECMWF
TROUGH ALONG WITH ITS FURTHER NORTHWEST UPPER LOW VERIFY. OVER AN
INCH OF RAINFALL TOTAL LOOKS LIKE A GOOD BET OVER THE WEEKEND AND
EARLY NEXT WEEK. OVERALL...WITH LARGE MODEL DIFFERENCES...CONFIDENCE
IS NOT STRONG ENOUGH TO MAKE ANY CHANGES TO THE INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 18Z TAFS/...
MVFR CONDITIONS EXPECTED TO LINGER ACROSS THE TAF SITES THROUGH
THE AFTERNOON.
SATELLITE IMAGES CONTINUE TO SHOW PESKY SC LINGERING ACROSS MUCH
OF THE STATE. RUC SEEMS TO REPRESENT THE ONGOING SITUATION
BEST...KEEPING LOWER LEVEL RH/S GREATER THAN 80% ACROSS THE AREA
THROUGH MUCH OF THE AFTERNOON. FURTHERMORE...A LAKE MICHIGAN
ENHANCED BAND OF CLOUDS SEEMS TO BE IN PLACE STREAMING SOUTHEAST
ACROSS LAF AND IND. THUS WILL KEEP THE MVFR CIGS IN THE FORECAST
UNTIL LATER TONIGHT WHEN THE UPPER RIDGE IS FINALLY EXPECTED TO
SLIDE EAST OF CENTRAL INDIANA.
ANY CLEARING MAY RESULT IN QUICK LOWER LEVEL SATURATION AS A GOOD
RADIATION COOLING SITUATION SETS UP. HAVE INCLUDED MVFR FOG AT
THE MORE RURAL TAF SITES LATE TONIGHT.
HIGH PRESSURE RIDGE AND DRY AIR WILL REMAIN ACROSS THE AREA ON
THURSDAY. THUS AFTER ANY MORNING FOG MIXES OUT...A RETURN TO VFR
IS EXPECTED AT ALL TAF SITES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...50
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...JP
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1233 AM EST WED NOV 23 2011
.AVIATION...
PCPN COMING TO AN END ACROSS THE AREA WITH KIWX 88D SHOWING BACK
EDGE THROUGH KSBN AT ISSUANCE. TIMING SUGGEST ENDING AT KFWA BY 08Z.
CIGS QUICKLY RISE WITH ENDING PCPN GOING FROM IFR TO VFR. KSBN
ALREADY VFR AND EXPECT KFWA TO TREND THAT WAY AS WELL AS RAIN ENDS.
SATELLITE SHOWS CLEARING MAKING STEADY PROGRESS EAST AND TIMING
SUGGEST CLEARING AT KSBN POSSIBLE BY 10Z WHICH WOULD YIELD A SHORT
PERIOD OF PRE-DAWN CLEAR SKIES WITH LIGHT WINDS. INTRODUCED MVFR VIS
FOR THIS GIVEN UPSTREAM DEVELOPMENT IN THIS CLEARING ALREADY. DRY
AIRMASS AND MIXING SHOULD ALLOW FOR QUICK DISSIPATION OF ANY FOG
AFTER SUNRISE. VFR REMAINDER OF DAY. CONCERN FOR ADDITIONAL FOG
DEVELOPMENT THURSDAY MORNING BUT THIS LOOKS TO BE JUST AFTER VALID
PERIOD OF CURRENT TAFS AND WILL BE LOOKED AT IN MORE DETAIL WITH
NEXT ISSUANCE.
&&
.UPDATE...
A STRONG LEAD VORT MAX TRACKING THROUGH FAR EASTERN PORTIONS OF
THE AREA LATE THIS EVENING SHOULD TAKE THE HEAVIER RAINFALL RATES
EAST OF THE AREA OVER THE NEXT HOUR. FOCUS THEN SHIFTS BACK ACROSS
NORTH CENTRAL PARTS OF THE FORECAST AREA WHERE STRONGER
DEFORMATION FORCING WILL SPREAD EASTWARD FROM FAR NORTHWEST
INDIANA. GIVEN GENERALLY OPEN AND PROGRESSIVE NATURE TO THE UPPER
WAVE...THIS DEFORMATION FORCING SHOULD MOVE STEADILY WEST TO EAST
ACROSS THE AREA THROUGH 06Z. DID MAKE SOME MINOR TWEAKS TO POP
GRIDS...BUT OVERALL NATURE OF PREVIOUS GRIDS WERE MAINTAINED
WITH WEST TO EAST DIMINISHMENT OF PRECIP AFTER 06Z. ONLY OTHER
TWEAKS TO FORECAST WERE WITH HOURLY TEMPS AS SOME BETTER MIXING
ACROSS EXTREME SOUTHEAST PORTIONS OF THE AREA ALLOWED FOR SOME
BRIEF MILDER TEMPS LATE THIS EVENING. DID ALSO ADD A MENTION OF
PATCHY FOG ACROSS EXTREME WRN PORTIONS OF THE AREA WERE SKIES ARE
EXPECTED TO CLEAR OUT TOWARD MORNING.
&&
.PREV DISCUSSION... /ISSUED 322 PM EST TUE NOV 22 2011/
SHORT TERM...
TONIGHT THROUGH WEDNESDAY NIGHT...
KIWX RADAR SHOWING LARGE EXPANSE OF MODERATE RAIN...WITH EMBEDDED
HEAVIER BANDS...COVERING THE ENTIRE CWA THIS AFTERNOON. SFC ANALYSIS
INDICATING LOW PRESSURE CENTER HAS MOVED INTO SW INDIANA...WITH
PRESSURE FALL ANALYSIS TAKING LOW ON NE TRACK BETWEEN DAYTON AND
LIMA THIS EVENING. THIS TRACK WOULD BRING 700MB LOW AND ASSOCIATED
DEFORMATION AXIS ACROSS THE AREA AND RESULT IN CONTINUED MODERATE TO
HEAVY RAIN OVER THE EASTERN HALF OF THE CWA THROUGH EARLY THIS
EVENING. WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS HAS UPPER
TROUGH OVER SE MO/W IL THIS AFTERNOON AND IS EXPECTED TO MAKES ITS
WAY EASTWARD TO IN/OH LINE BY 06Z AND BRING AN END TO THE PRECIP BY
LATE TONIGHT TO THE EASTERN CWA. SFC HIGH PRESSURE TO BUILD INTO THE
REGION ON WEDNESDAY AND BRING A QUIET WEATHER PATTERN TO THE REGION
HEADING TOWARD THE THANKSGIVING HOLIDAY ALONG WITH SEASONABLE TEMPS
WITH HIGHS WEDNESDAY NEAR 50 AND L30S FOR LOWS.
&&
LONG TERM.../THURSDAY THROUGH TUESDAY/
MODELS IN GOOD AGREEMENT LATE THIS WEEK THAT A GRADUALLY
STRENGTHENING LONG WAVE TROF WILL PROGRESS EASTWARD ACROSS THE WRN
U.S. WHILE AHEAD OF IT A STRONG UPR LEVEL RIDGE WILL MOVE EAST
ACROSS ERN PORTIONS OF THE COUNTRY. THIS SHOULD RESULT IN A WARM DRY
AIRMASS IMPACTING OUR CWA THU-FRI. LITTLE CLOUDINESS AND DECENT
MIXING FOR THIS TIME OF YEAR...ESPECIALLY FRIDAY... SHOULD ALLOW
HIGHS TO REACH THE M50S THU AND THE L60S FRI OVER MOST OF THE CWA.
TEMPS SHOULD REMAIN ABOVE NORMAL SATURDAY... BUT WITH UPR RIDGE
MOVG TO THE EAST COAST AND INCRSG CLOUDS AND PRBLY EVENTUALLY
SHOWERS ASSOCIATED WITH THE APCHG TROF SPREADING INTO THE CWA DURING
THE DAY... HIGHS SHOULD BE A BIT LOWER THAN FRIDAY... IN THE M50S.
THE LONG WAVE IS FCST BY ALL OPERATIONAL MEDIUM RANGE MODELS TO
CLOSE/CUT OFF OVER THE CENTRAL U.S. SUNDAY... BUT LARGE DIFFERENCES
REMAIN ON WHERE THIS WILL OCCUR BOTH AMONG LATEST GUIDANCE AND AMONG
THEIR RESPECTIVE RECENT RUNS. GFS ENSEMBLES ALSO SUGGESTING CUT OFF
LOW WILL DEVELOP BUT SPREAD IS VERY LARGE. THUS, CONFIDENCE IN LONG
RANGE FCST GOOD THROUGH SAT... THEN GOES DOWNHILL SUNDAY THROUGH
TUE... THOUGH DOES APPEAR THAT TEMPS WILL BE CONSIDERABLY
COOLER...CLOSER TO IF NOT BLO NORMAL EARLY NEXT WEEK. ALSO HARD ATTM
TO LEAVE OUT A CHC OF PRECIP IN EACH 12HR PERIOD SUN-TUE GIVEN
POTENTIAL FOR LOW CLOSING/CUTTING OFF OVER CENTRAL U.S. SUNDAY AND
THEN SLOWLY LIFTING OUT TO THE NE MON-TUE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST WEDNESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...JT
AVIATION...LASHLEY
UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1138 PM CST TUE NOV 22 2011
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE FORECAST (TODAY THROUGH WEDNESDAY)
20Z WATER VAPOR SHOWS THE UPPER WAVE THAT BROUGHT THE RAIN THIS
MORNING CONTINUES TO MOVE EAST WITH A SHORTWAVE RIDGE BUILDING INTO
THE CENTRAL PLAINS. AT THE SFC THERE WAS A BROAD AND WEAK RIDGE OVER
MUCH OF THE CENTRAL U.S.
FOR TONIGHT AND WEDNESDAY...THE MAIN CONCERN IS THE LOW CLOUDS AND
POTENTIAL FOR DENSE FOG FORMING. INCREASING SUBSIDENCE FROM THE
SHORTWAVE RIDGE SHOULD PREVENT ANY PRECIPITATION FROM OCCURRING.
HOWEVER THE LOW STRATUS HAS PREVENTED THE BOUNDARY LAYER FROM MIXING
OUT THIS AFTERNOON AND DEWPOINTS REMAIN IN THE 30S AND LOW 40S. BOTH
THE NAM AND RUC INSIST ON THE STRATUS DECK MOVING EAST EARLY THIS
EVENING. IF THIS IN FACT OCCURS...THE SETUP FOR RADIATIONAL FOG
LOOKS GOOD WITH CLEAR SKIES AND VERY LIGHT WINDS ANTICIPATED
OVERNIGHT. RIGHT NOW THE FORECAST HAS MIN TEMPS FORECAST TO BE
ANYWHERE BETWEEN 5 AND 10 DEGREES COOLER THAN THE CURRENT OBSERVED
DEWPOINTS. SINCE THERE CONTINUES TO BE UNCERTAINTY IN THE STRATUS
MOVING EAST...THE LOW TEMP FORECAST COULD BE TO COOL AND RADIATIONAL
COOLING MAY NOT DEVELOP. OTHERWISE I WOULD CONSIDER A DENSE FOG
ADVISORY THROUGH WEDNESDAY MORNING. THE EVENING SHIFT SHOULD BE ABLE
TO MONITOR CLOUD COVER AND SEE IF DENSE FOG WILL FORM AND THE MOST
LIKELY LOCATION FOR ITS FORMATION. OTHERWISE MODELS SHOW WARM AIR
ADVECTING IN FROM THE SOUTH FOR WEDNESDAY WITH THE BOUNDARY LAYER
MIXING TO AROUND 925MB. THIS SHOULD LEAD TO HIGHS IN THE LOWER AND
MIDDLE 60S TOMORROW AFTERNOON.
WOLTERS
MID RANGE FORECAST (WEDNESDAY NIGHT THROUGH FRIDAY)
MODEL CONTINUE TO SHOW WARM ADVECTION INCREASING WEDNESDAY NIGHT AS
WELL AS AN INCREASE IN MIXING. AS A RESULT...EXPECT LOWS TO BE 8 TO
10 DEGREES ABOVE TONIGHTS LOWS...ALTHOUGH SKIES WILL BE CLEAR.
ALTHOUGH SOME HIGH CLOUDS WILL MOVE INTO THE COUNTY WARNING AREA
(CWA) ON THANKSGIVING...THEY SHOULD NOT BE THICK ENOUGH TO OFFSET
THE PERSISTENT WARM AIR ADVECTION. AXIS OF WARMER AIR AND WARMEST
HIGH TEMPS STILL APPEARS WILL SET UP FROM NEAR SALINA INTO THE
MANHATTAN AREA WHERE TEMPS SHOULD APPROACH 70 BY MID
AFTERNOON...ALTHOUGH THE MIDDLE TO UPPER 60S LOOK IN STORE FOR
MOST LOCATIONS IN THE CWA.
LATE THURSDAY NIGHT AND ESPECIALLY DURING THE DAY FRIDAY...SOME LOW
LEVEL MOISTURE WILL BEGIN TO ADVECT NORTHWARD INTO THE
CWA...ALTHOUGH IT WILL PRIMARILY OCCUR IN THE LATTER HALF OF THE DAY
AS THE ATMOSPHERE IN THE 700-850MB LAYER WILL BE SLOW TO MOISTEN.
WILL KEEP CHANCE POPS ALL AREAS EXCEPT THE SOUTHEAST CORNER OF THE
CWA. ALSO...ELEVATED CAPE REMAINS VERY LIMITED AT BEST...SO WILL
KEEP WEATHER GRIDS AS SHOWERS FOR NOW.
ALTHOUGH FRIDAY WILL START OUT A GOOD 15 DEGREES ABOVE NORMAL...
THE AXIS OF WARMER LLVL TEMPS WILL STEADILY SHIFT SOUTHEAST OF THE
CWA AS CLOUDS THICKEN THROUGH THE DAY. THE SOUTHEAST HALF OF THE CWA
SHOULD RISE INTO THE LOWER 60S TO MIDDLE 60S....BUT THE NORTHWEST
COUNTIES SHOULD ONLY MAKE IT INTO THE MIDDLE TO UPPER 50S. 63
EXTENDED FORECAST (FRIDAY NIGHT THROUGH TUESDAY)
FRIDAY NIGHT A HIGHLY AMPLIFIED SHORTWAVE TROUGH WILL MOVE OUT OF
THE DESERT SOUTHWEST INTO THE CENTRAL PLAINS. A COLD FRONT WILL MOVE
EAST ACROSS THE STATE OF KANSAS ON FRIDAY AND GRADUALLY CLEAR THE
CWA EARLY SATURDAY MORNING. BUMPED UP PRECIPITATION CHANCES ON FRIDAY
NIGHT INTO SATURDAY MORNING WITH GOOD AGREEMENT IN THE MEDIUM TO
LONG RANGE MODELS...GOOD UPPER LEVEL SUPPORT FOR PRECIPITATION AND
MODEL SOUNDINGS INDICATING A DEEP SATURATED LAYER DURING THIS
TIME-FRAME. MODELS THEN CLOSE THE UPPER LEVEL LOW OFF TO THE EAST OF
THE CWA BUT DIFFER ON WHERE THE LOW WILL CUT OFF AND VARY FROM THE
GREAT LAKES REGION TO THE SOUTHEAST U.S. THIS IS HIGHLY DEPENDENT
UPON THE STRENGTH AND AMPLIFICATION OF THE UPPER LEVEL WAVE.
HOWEVER...THE CENTRAL U.S. WILL REMAIN ON THE WESTERN SIDE OF THE
CUT OFF LOW WHICH WILL KEEP NORTHWESTERLY FLOW AND COLD AIR
ADVECTION OVER THE REGION FOR THE REMAINDER OF THE EXTENDED FORECAST
WITH COOLER AND DRY CONDITIONS EXPECTED FOR LATE NEXT WEEKEND INTO
EARLY NEXT WEEK.
ANDERSON
&&
.AVIATION...
WESTERN EDGE OF STRATUS OVER EASTERN KS HAS STOPPED ITS EASTWARD
PROGRESS AND MAY BE HANGING AROUND AWHILE IN EASTERN COUPLE TIERS
OF COUNTIES. MOIST AIR AND MOSTLY CLEAR SKIES IN MHK TONIGHT
SHOULD LEAD TO DENSE FOG DEVELOPMENT WITH BECOMING VFR AFTER 15
OR 16Z. AT TOP AND FOE...WHEN STRATUS CLEARS OUT...ALSO EXPECT
DEVELOPMENT OF DENSE FOG WITH LIFR VISIBILITIES...ALSO BREAKING UP
BY MID MORNING. VFR AT ALL SITES EXPECTED FROM LATE MORNING ON.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1100 AM EST WED NOV 23 2011
.Short-Term Update (This Afternoon - Tonight)...
Low clouds are very persistent this morning over central Kentucky
and southern Indiana, within moist low-level northwest flow. ILN 12
UTC sounding shows rather deep moist layer to about 700 mb, with OHX
sounding moist to about 800mb. 12z model soundings thin the moist
layer and still allow clearing to occur this afternoon. In addition,
a few AMDAR ascent/descent aircraft soundings suggest the moist
layer has thinned a bit from 12z RAOB soundings. As a result, will
still indicate gradual clearing in forecast this afternoon, but have
delayed onset, keeping low clouds locked in place a little longer
than earlier forecast. In response, have lowered max temps a degree
or two in some areas, but if sunshine does break through, temps will
only have to rise a few degrees to reach originally projected
values. Otherwise, forecast is on track with no other significant
changes needed at this time.
&&
.Short Term (This Afternoon - Tonight)...
Low clouds are very persistent this morning over central Kentucky
and southern Indiana, within moist low-level northwest flow. ILN 12
UTC sounding shows rather deep moist layer to about 700 mb, with OHX
sounding moist to about 800mb. 12z model soundings thin the moist
layer and still allow clearing to occur this afternoon. In addition,
a few AMDAR ascent/descent aircraft soundings suggest the moist
layer has thinned a bit from 12z RAOB soundings. As a result, will
still indicate gradual clearing in forecast this afternoon, but have
delayed onset, keeping low clouds locked in place a little longer
than earlier forecast. In response, have lowered max temps a degree
or two in some areas, but if sunshine does break through, temps will
only have to rise a few degrees to reach originally projected
values. Otherwise, forecast is on track with no other significant
changes needed at this time.
.Long term (Thursday - Tuesday)...
Well, many areas could be greeted on Thanksgiving morning with
patchy dense fog, especially over the eastern CWA. This may take
some time to burn off in the morning with ridging sliding in
overhead, but with winds starting to pick up a tad from the south,
sunny skies and mixing should burn that off by mid-morning. It will
be a very pleasant day to enjoy your turkey, with afternoon highs in
the upper 50s to the very low 60s. To round out the work week,
surface high pressure will slide to the east as upper level ridging
continues our mostly clear skies and warming conditions. After
Thanksgiving night lows in the upper 30s and low 40s, shoppers can
expect highs Friday in the low-mid 60s, with more mild lows Friday
night in the 40s.
By Saturday, the ridge will shift eastward as troughing from the
Pacific NW and the southwest CONUS join on the lee of the Rockies to
produce elongated low pressure over the Plains. Both the 00z Euro
and GFS show the northern stream trough taking over and developing a
stronger surface low over the Great Lakes and pushing its cold front
towards our western CWA on Saturday. Kept high chance POPs over the
far west and slight chance POPs towards our central CWA. The front
should swing through late Saturday night into Sunday, with ample
rainfall and embedded thunderstorms expected along it. Have likely
and categorical POPs Saturday night, but these could easily push
into Sunday. Although the Euro lags the GFS a bit, they both
indicate the upper trough over the Mid-Mississippi Valley region
Sunday night wrapping up into a closed low, which will then, in
turn, create another surface low pressure by Monday. By Monday night
and into Tuesday, the upper low sinks as far south as the Gulf
States with the surface low developing just downstream and wrapping
back up to the north under the large upper-level divergent region.
Although the details are going to change from now until then, this
solution with the cut-off low overhead would keep chance showers
across the region through much of the extended and possibly beyond.
Although the models have come in a bit warmer than yesterday`s 00z
runs, there still appears to be a chance of some rain/snow mix
Sunday night and especially Monday night. By Tuesday night, the
lower Ohio Valley will be on the back side of this system, which
could result in just plain snow showers across our region. Much
uncertainty still remains with the timing and placement of these
features, but it does appear to bring about an active period for
several days. Highs in the coolish 50s for Sunday should drop into
the 40s for highs for early next week given the amount of cloud
cover and cold air aloft expected with this potential cut-off low.
&&
.Aviation (12Z TAF Issuance)...
A large field of low level stratocu extends all the way back into
the upper Mississippi Valley and Great Lakes. It normally takes
quite a while for these sorts of post-frontal cloud fields to clear
out, and indeed the NAM12, GFS40, and HRRR hold the clouds in until
early to mid afternoon. Cloud bases are fairly uniform across the
region, mostly low end MVFR with some patchy high-end IFR.
Winds today will be much lighter than yesterday as Tuesday`s storm
system pulls off to the northeast and is replaced by high pressure
coming in from the southern Plains. By late this afternoon into
tonight skies will be clear with light and variable winds.
Fog is expected to form after midnight tonight with the clear skies,
light winds, and soaked ground. BWG should be most affected,
followed by LEX and SDF in order of severity and persistence.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........TWF
Short Term.......13
Long Term........AL
Aviation.........13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
551 AM EST WED NOV 23 2011
...Updated Aviation Discussion...
.Short Term (Today - Tonight)...
Other than perhaps a stray patch of drizzle early this morning,
today and tonight will be dry as yesterday`s storm system pulls off
to the northeast and high pressure comes in from the west.
Today`s main challenge is the low cloud deck, and when it will scour
out. RH profiles on the NAM, GFS, and HRRR all agree that the low
clouds will stick around into this afternoon, especially over
Kentucky. Also, the tendency of the models is to clear out clouds
too quickly, especially during the cool season. For these reasons
we will be somewhat pessimistic with sky cover for this morning into
early this afternoon. One possible game-changer is an area of
clearing currently stretching from Wisconsin into Illinois and
Iowa. It is trying to dive to the south, but really is only making
slow forward progress so far and the models keep the bulk of this
clearing just to our north today. So, bottom line, we will go with
cloudy skies this morning and gradual clearing this afternoon.
As for temperatures today, will go on the low side of guidance given
the pessimistic cloud forecast. Temperatures will start the day in
the middle 40s at best, so with clouds and a northwest breeze in
late November it`s hard to imagine temperatures would rise very
much. Also, highs upstream yesterday were only in the 40s, and
diurnal ranges were on the order of just a few degrees. Will go with
highs generally in the lower 50s, but the max temp today will be
highly dependent on cloud cover.
Tonight that high to our west will move into the Tennessee Valley,
giving us clear skies and little wind. However, those conditions
plus the copious rainfall we have received lately will result in
fog. Right now will have the most widespread fog across the
southeast half of the LMK CWA with just valley fog in the northwest
where dew point depressions look to be a bit larger, but the fog
area may need to be expanded in future forecasts. Low temperatures
tonight will be in the lower to middle 30s.
.Long term (Thursday - Tuesday)...
Well, many areas could be greeted on Thanksgiving morning with
patchy dense fog, especially over the eastern CWA. This may take
some time to burn off in the morning with ridging sliding in
overhead, but with winds starting to pick up a tad from the south,
sunny skies and mixing should burn that off by mid-morning. It will
be a very pleasant day to enjoy your turkey, with afternoon highs in
the upper 50s to the very low 60s. To round out the work week,
surface high pressure will slide to the east as upper level ridging
continues our mostly clear skies and warming conditions. After
Thanksgiving night lows in the upper 30s and low 40s, shoppers can
expect highs Friday in the low-mid 60s, with more mild lows Friday
night in the 40s.
By Saturday, the ridge will shift eastward as troughing from the
Pacific NW and the southwest CONUS join on the lee of the Rockies to
produce elongated low pressure over the Plains. Both the 00z Euro
and GFS show the northern stream trough taking over and developing a
stronger surface low over the Great Lakes and pushing its cold front
towards our western CWA on Saturday. Kept high chance POPs over the
far west and slight chance POPs towards our central CWA. The front
should swing through late Saturday night into Sunday, with ample
rainfall and embedded thunderstorms expected along it. Have likely
and categorical POPs Saturday night, but these could easily push
into Sunday. Although the Euro lags the GFS a bit, they both
indicate the upper trough over the Mid-Mississippi Valley region
Sunday night wrapping up into a closed low, which will then, in
turn, create another surface low pressure by Monday. By Monday night
and into Tuesday, the upper low sinks as far south as the Gulf
States with the surface low developing just downstream and wrapping
back up to the north under the large upper-level divergent region.
Although the details are going to change from now until then, this
solution with the cut-off low overhead would keep chance showers
across the region through much of the extended and possibly beyond.
Although the models have come in a bit warmer than yesterday`s 00z
runs, there still appears to be a chance of some rain/snow mix
Sunday night and especially Monday night. By Tuesday night, the
lower Ohio Valley will be on the back side of this system, which
could result in just plain snow showers across our region. Much
uncertainty still remains with the timing and placement of these
features, but it does appear to bring about an active period for
several days. Highs in the coolish 50s for Sunday should drop into
the 40s for highs for early next week given the amount of cloud
cover and cold air aloft expected with this potential cut-off low.
&&
.Aviation (12Z TAF Issuance)...
A large field of low level stratocu extends all the way back into
the upper Mississippi Valley and Great Lakes. It normally takes
quite a while for these sorts of post-frontal cloud fields to clear
out, and indeed the NAM12, GFS40, and HRRR hold the clouds in until
early to mid afternoon. Cloud bases are fairly uniform across the
region, mostly low end MVFR with some patchy high-end IFR.
Winds today will be much lighter than yesterday as Tuesday`s storm
system pulls off to the northeast and is replaced by high pressure
coming in from the southern Plains. By late this afternoon into
tonight skies will be clear with light and variable winds.
Fog is expected to form after midnight tonight with the clear skies,
light winds, and soaked ground. BWG should be most affected,
followed by LEX and SDF in order of severity and persistence.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......13
Long Term........AL
Aviation.........13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
307 AM EST WED NOV 23 2011
.Short Term (Today - Tonight)...
Other than perhaps a stray patch of drizzle early this morning,
today and tonight will be dry as yesterday`s storm system pulls off
to the northeast and high pressure comes in from the west.
Today`s main challenge is the low cloud deck, and when it will scour
out. RH profiles on the NAM, GFS, and HRRR all agree that the low
clouds will stick around into this afternoon, especially over
Kentucky. Also, the tendency of the models is to clear out clouds
too quickly, especially during the cool season. For these reasons
we will be somewhat pessimistic with sky cover for this morning into
early this afternoon. One possible game-changer is an area of
clearing currently stretching from Wisconsin into Illinois and
Iowa. It is trying to dive to the south, but really is only making
slow forward progress so far and the models keep the bulk of this
clearing just to our north today. So, bottom line, we will go with
cloudy skies this morning and gradual clearing this afternoon.
As for temperatures today, will go on the low side of guidance given
the pessimistic cloud forecast. Temperatures will start the day in
the middle 40s at best, so with clouds and a northwest breeze in
late November it`s hard to imagine temperatures would rise very
much. Also, highs upstream yesterday were only in the 40s, and
diurnal ranges were on the order of just a few degrees. Will go with
highs generally in the lower 50s, but the max temp today will be
highly dependent on cloud cover.
Tonight that high to our west will move into the Tennessee Valley,
giving us clear skies and little wind. However, those conditions
plus the copious rainfall we have received lately will result in
fog. Right now will have the most widespread fog across the
southeast half of the LMK CWA with just valley fog in the northwest
where dew point depressions look to be a bit larger, but the fog
area may need to be expanded in future forecasts. Low temperatures
tonight will be in the lower to middle 30s.
.Long term (Thursday - Tuesday)...
Well, many areas could be greeted on Thanksgiving morning with
patchy dense fog, especially over the eastern CWA. This may take
some time to burn off in the morning with ridging sliding in
overhead, but with winds starting to pick up a tad from the south,
sunny skies and mixing should burn that off by mid-morning. It will
be a very pleasant day to enjoy your turkey, with afternoon highs in
the upper 50s to the very low 60s. To round out the work week,
surface high pressure will slide to the east as upper level ridging
continues our mostly clear skies and warming conditions. After
Thanksgiving night lows in the upper 30s and low 40s, shoppers can
expect highs Friday in the low-mid 60s, with more mild lows Friday
night in the 40s.
By Saturday, the ridge will shift eastward as troughing from the
Pacific NW and the southwest CONUS join on the lee of the Rockies to
produce elongated low pressure over the Plains. Both the 00z Euro
and GFS show the northern stream trough taking over and developing a
stronger surface low over the Great Lakes and pushing its cold front
towards our western CWA on Saturday. Kept high chance POPs over the
far west and slight chance POPs towards our central CWA. The front
should swing through late Saturday night into Sunday, with ample
rainfall and embedded thunderstorms expected along it. Have likely
and categorical POPs Saturday night, but these could easily push
into Sunday. Although the Euro lags the GFS a bit, they both
indicate the upper trough over the Mid-Mississippi Valley region
Sunday night wrapping up into a closed low, which will then, in
turn, create another surface low pressure by Monday. By Monday night
and into Tuesday, the upper low sinks as far south as the Gulf
States with the surface low developing just downstream and wrapping
back up to the north under the large upper-level divergent region.
Although the details are going to change from now until then, this
solution with the cut-off low overhead would keep chance showers
across the region through much of the extended and possibly beyond.
Although the models have come in a bit warmer than yesterday`s 00z
runs, there still appears to be a chance of some rain/snow mix
Sunday night and especially Monday night. By Tuesday night, the
lower Ohio Valley will be on the back side of this system, which
could result in just plain snow showers across our region. Much
uncertainty still remains with the timing and placement of these
features, but it does appear to bring about an active period for
several days. Highs in the coolish 50s for Sunday should drop into
the 40s for highs for early next week given the amount of cloud
cover and cold air aloft expected with this potential cut-off low.
&&
.Aviation (06Z TAF Issuance)...
A large field of low level stratocu extends all the way back into
the upper Mississippi Valley and Great Lakes. It normally takes
quite a while for these sorts of post-frontal cloud fields to clear
out, and indeed the NAM12, GFS40, and HRRR hold the clouds in until
mid afternoon. Cloud bases are fairly uniform across the region,
mostly low end MVFR with some patchy high-end IFR.
Winds will gradually settle down overnight as Tuesday`s storm system
pulls off to the northeast and is replaced by high pressure coming
in from the southern Plains. By late this afternoon into tonight
skies will be clear with light and variable winds.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......13
Long Term........AL
Aviation.........13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1204 AM EST WED NOV 23 2011
...Updated Aviation Discussion...
.Short Term (Tonight - Wednesday)...
Cold front will move through our area this evening, switching gusty
south-to-southwest winds to west and then northwest overnight. It
will be a cloudy night as temperatures fall into the lower to mid
40s by Wednesday morning.
During the day Wednesday, low clouds will clear out from northwest
to southeast starting in the morning, with clearing in the afternoon
over eastern areas. High temperatures will be in the 50s.
.Long term (Wednesday Night - Tuesday)...
High pressure at the surface will be centered over the region
Wednesday night and Thursday with ridging building in aloft. The
high pressure will shift east on Friday, though it still will be in
control. This will lead to a quite pleasant Thanksgiving and Black
Friday. Skies will be mostly clear with temperatures on Thanksgiving
topping out in the upper 50s to around 60. Friday will be even
warmer, starting out around 40 and rising into the lower to mid 60s.
The next system will begin to approach from the west on Saturday. A
low pressure system will cross the Great Lakes into Canada through
the weekend. The cold front associated with this system looks to now
move into the area Saturday night. Rain and thunderstorms will
approach the western border of the forecast area late Saturday
afternoon or early evening. Moderate to heavy rain with embedded
thunderstorms should overspread the area overnight Saturday through
Sunday.
Sunday afternoon into early next week is still a bit of a question
mark. The latest run of the ECMWF is now in agreement with the GFS
in spinning up a second low in the southern stream as an upper level
low becomes cutoff over the lower Ohio Valley. This would keep
chances for precipitation in the forecast through mid week.
Additionally, the upper level low will pull in much colder air. With
lows bottoming out in the mid 30s Sunday night and low 30s Monday
night, there will be a chance for some snow to mix in with the light
rain. As always this far out, there is the potential for the details
of this system to change quite a bit over the next few days, so be
sure to monitor future forecasts.
&&
.Aviation (06Z TAF Issuance)...
A large field of low level stratocu extends all the way back into
the upper Mississippi Valley and Great Lakes. It normally takes
quite a while for these sorts of post-frontal cloud fields to clear
out, and indeed the NAM12, GFS40, and HRRR hold the clouds in until
mid afternoon. Cloud bases are fairly uniform across the region,
mostly low end MVFR with some patchy high-end IFR.
Winds will gradually settle down overnight as Tuesday`s storm system
pulls off to the northeast and is replaced by high pressure coming
in from the southern Plains. By late this afternoon into tonight
skies will be clear with light and variable winds.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......TWF
Long Term........EER
Aviation.........13
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
937 PM EST THU NOV 24 2011
.SYNOPSIS...
LOW CLOUDS WILL REDEVELOP TONIGHT...ALTHOUGH HIGH PRESSURE WILL
PROVIDE SUNSHINE ON FRIDAY ALONG WITH MILDER TEMPERATURES. A
FRONTAL SYSTEM WILL AFFECT THE AREA LATE SATURDAY NIGHT INTO EARLY
NEXT WEEK WITH PERIODS OF SHOWERS.
&&
.NEAR TERM /THROUGH FRIDAY/...
FORECAST REMAINS DIFFICULT. INSTEAD OF AREA OF LOW CLOUDS
EXPANDING ACROSS THE REGION...THE CLOUD DECK HAS SIMPLY MOVED TO
THE NORTHEAST SLOWLY DURING THE EVENING HOURS. IN ITS
WAKE...VISIBILITIES ARE BEGINNING TO FALL...WITH PARKERSBURG
ALREADY DOWN TO 1/2 HALF MILE VISIBILITY AND LOW CLOUDS. WITH 03Z
UPDATE...HAVE USED THE LATEST RUN OF THE HRRR TO SHOW MOVEMENT OF
CLOUDS TO THE NORTHEAST...WHICH SHOULD EXIT BY SUNRISE. HAVE ALSO
DEPICTED PATCHY FOG DEVELOPING IN ALL LOCATIONS AS CLOUDS
DEPART...WITH AREAS OF FOG IN VALLEYS. HAVE SLIGHTLY MORE
CONFIDENCE IN THIS FORECAST THAN PREVIOUS FORECAST...BUT OVERALL
CONFIDENCE STILL REMAINS LOW.
LOW LEVEL MOISTURE MAY BEGIN TO ERODE TOMORROW...ALLOWING FOR
CLEAR SKIES IN ALL LOCATIONS BY THE AFTERNOON. LOW TEMPERATURES
WILL BE IN THE LOWER TO MID 30S...WITH UPPER 20S IN THE NORTHERN
WV MOUNTAINS. FRIDAY AFTERNOON TEMPERATURES SHOULD REBOUND INTO
THE UPPER 50S AND LOWER 60S.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AREA OF HIGH PRESSURE CENTERED OVER THE SOUTHEASTERN STATES WILL
DRIFT OFF THE ATLANTIC COAST BY SATURDAY. THIS WILL PROVIDE DRY
CONDITIONS AND MILD TEMPERATURES THROUGH SATURDAY EVENING.
CLOUDS WILL BE ON THE INCREASE LATE SATURDAY AHEAD OF A COLD
FRONT MOVING ACROSS THE MIDWEST. THIS SYSTEM WILL SLOWLY CROSS THE
FORECAST AREA ON SUNDAY. SHOWERS WILL SPREAD EASTWARD INTO EAST
CENTRAL OH LATE SATURDAY NIGHT AND ACROSS THE ENTIRE AREA SUNDAY.
PRECIPITATION AND CLOUD COVER WILL LIMIT TEMPERATURES TO THE UPPER
40S AND LOWER 50S SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED FORECAST WILL FOLLOW NEW GFS AND HPC PROGS WITH COLD
ADVECTION AND SNOW SHOWERS MONDAY AS UPPER TROUGH MOVES EAST OF
GREAT LAKES AND STRONG SURFACE LOW MOVES OFFSHORE NEW ENGLAND.
NEXT COLD FRONT APPROACHES REGION TUESDAY WITH CHANCE POPS AND A
REINFORCING SHOT OF COLD AIR FOR WEDNESDAY INTO THURSDAY.
TEMPERATURES WILL AVERAGE BELOW NORMAL THROUGH PERIOD AS A LARGE
UPPER LEVEL TROUGH IS EXPECTED TO BE ESTABLISHED ACROSS THE
NATIONS MID SECTION.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
WITH LOW LEVEL MOISTURE SET IN PLACE, LOW CLOUDS HAVE LINGERED IN
THE REGION AND WILL REMAIN AND WILL LOWER OVERNIGHT WITH IFR
CEILINGS PREVAILING. LATE NIGHT FOG WILL DEVELOP ACROSS THE REGION
REDUCING VISIBILITY. HAVE LOW CONFIDENCE AS TO HOW LOW VISIBILITY
WILL BE BUT HAVE TEMPO GROUPS FOR IFR VISIBILITY BEFORE SUNRISE.
EXPECT A RETURN TO VFR CONDITIONS FOLLOWING THE SLOW DIMINISH OF
FOG/STRATUS FOR FRIDAY.
OUTLOOK... FRIDAY NIGHT THROUGH TUESDAY...
VFR INTO SATURDAY EVENING. PREFRONTAL SHOWERS WITH RESTRICTIONS
POSSIBLE STARTING LATE SATURDAY NIGHT INTO SUNDAY AFTERNOON. RAIN
AND SNOW SHOWERS WITH RESTRICTIONS MAY BE POSSIBLE MONDAY THROUGH
TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
720 PM EST THU NOV 24 2011
.SYNOPSIS...
LOW CLOUDS WILL REDEVELOP TONIGHT...ALTHOUGH HIGH PRESSURE WILL
PROVIDE SUNSHINE ON FRIDAY ALONG WITH MILDER TEMPERATURES. A
FRONTAL SYSTEM WILL AFFECT THE AREA LATE SATURDAY NIGHT INTO EARLY
NEXT WEEK WITH PERIODS OF SHOWERS.
&&
.NEAR TERM /THROUGH FRIDAY/...
CONSIDERING NO PRECIPITATION IS EXPECTED...A SURPRISINGLY
DIFFICULT FORECAST. MODELS HAVE BEEN DOING A POOR JOB INDICATING
WHERE CLOUD COVER IS EXPECTED OVER THE LAST 12-18 HOURS. ALTHOUGH
LOW STRATUS BEGAN TO DISSIPATE IN SOME LOCATIONS BY EARLY
AFTERNOON...A LARGE AREA NEVER DISSIPATED AND IS CURRENTLY OVER
THE WESTERN HALF OF THE REGION. WITH LOSS OF DAYTIME
HEATING...EXPECT THAT THIS CLOUD DECK WILL ONLY EXPAND IN AREAL
COVERAGE. HAVE FOLLOWED THE HRRR TO TRY AND DEPICT HOW THE CLOUDS
WILL EXPAND OVER TIME TONIGHT. IN A CHANGE FROM NORMAL...IT
APPEARS THAT THE WV/MD RIDGES MAY END UP BEING THE ONLY AREA THAT
DOES NOT HAVE CLOUD COVER. CONSIDERING FOG DEVELOPED IN SOME
LOCATIONS LAST NIGHT UNDERNEATH STRATUS...HAVE NOT REMOVED FOG
FROM LOCATIONS THAT WERE EXPECTED TO REMAIN CLEAR IN PREVIOUS
FORECAST. HAVE ALMOST NO CONFIDENCE IN WHERE FOG WILL DEVELOP
UNDER CLOUDS TONIGHT. EXTENSIVE CLOUD COVER SHOULD KEEP
TEMPERATURES WARMER THAN LAST NIGHT. LOW LEVEL MOISTURE MAY BEGIN
TO ERODE TOMORROW...ALLOWING FOR CLEAR SKIES IN ALL LOCATIONS BY
THE AFTERNOON.
LOW TEMPERATURES WILL BE IN THE LOWER TO MID 30S...WITH UPPER 20S IN
THE NORTHERN WV MOUNTAINS. FRIDAY AFTERNOON TEMPERATURES SHOULD
REBOUND INTO THE UPPER 50S AND LOWER 60S.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AREA OF HIGH PRESSURE CENTERED OVER THE SOUTHEASTERN STATES WILL
DRIFT OFF THE ATLANTIC COAST BY SATURDAY. THIS WILL PROVIDE DRY
CONDITIONS AND MILD TEMPERATURES THROUGH SATURDAY EVENING.
CLOUDS WILL BE ON THE INCREASE LATE SATURDAY AHEAD OF A COLD
FRONT MOVING ACROSS THE MIDWEST. THIS SYSTEM WILL SLOWLY CROSS THE
FORECAST AREA ON SUNDAY. SHOWERS WILL SPREAD EASTWARD INTO EAST
CENTRAL OH LATE SATURDAY NIGHT AND ACROSS THE ENTIRE AREA SUNDAY.
PRECIPITATION AND CLOUD COVER WILL LIMIT TEMPERATURES TO THE UPPER
40S AND LOWER 50S SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED FORECAST WILL FOLLOW NEW GFS AND HPC PROGS WITH COLD
ADVECTION AND SNOW SHOWERS MONDAY AS UPPER TROUGH MOVES EAST OF
GREAT LAKES AND STRONG SURFACE LOW MOVES OFFSHORE NEW ENGLAND.
NEXT COLD FRONT APPROACHES REGION TUESDAY WITH CHANCE POPS AND A
REINFORCING SHOT OF COLD AIR FOR WEDNESDAY INTO THURSDAY.
TEMPERATURES WILL AVERAGE BELOW NORMAL THROUGH PERIOD AS A LARGE
UPPER LEVEL TROUGH IS EXPECTED TO BE ESTABLISHED ACROSS THE
NATIONS MID SECTION.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
WITH LOW LEVEL MOISTURE SET IN PLACE, LOW CLOUDS HAVE LINGERED IN
THE REGION AND WILL REMAIN AND WILL LOWER OVERNIGHT WITH IFR
CEILINGS PREVAILING. LATE NIGHT FOG WILL DEVELOP ACROSS THE REGION
REDUCING VISIBILITY. HAVE LOW CONFIDENCE AS TO HOW LOW VISIBILITY
WILL BE BUT HAVE TEMPO GROUPS FOR IFR VISIBILITY BEFORE SUNRISE.
EXPECT A RETURN TO VFR CONDITIONS FOLLOWING THE SLOW DIMINISH OF
FOG/STRATUS FOR FRIDAY.
OUTLOOK... FRIDAY NIGHT THROUGH TUESDAY...
VFR INTO SATURDAY EVENING. PREFRONTAL SHOWERS WITH RESTRICTIONS
POSSIBLE STARTING LATE SATURDAY NIGHT INTO SUNDAY AFTERNOON. RAIN
AND SNOW SHOWERS WITH RESTRICTIONS MAY BE POSSIBLE MONDAY THROUGH
TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1133 AM EST WED NOV 23 2011
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL RIDGE
OVER THE WRN CONUS GRADUALLY EXPANDING TOWARD THE WRN GREAT LAKES. A
SHRTWV ATOP THE RIDGE WAS MOVING THROUGH CNTRL MANITOBA. AT THE
SFC...A RIDGE PERSITED OVER THE WRN LAKES BTWN A 997 MB LOW NEAR
LAKE WINNIPEG AND A 1001 MB LOW OVER NW PA. WRLY 925-900 MB WINDS
WERE HELPING TO PUSH A STRATUS DECK EASTWARD THROUGH CENTRL UPPER
MI.
&&
.DISCUSSION
TODAY...EXPECT THAT AS THE MANITOBA LOW PRES SLIDS OFF TO THE EAST
THROUGH NRN ONTARIO...THE INCREASING WRLY LOW LEVEL FLOW WILL BRING
THE BACK EDGE OF THE CLOUD DECK(CURRENTLY OVER NW MN) THROUGH THE
CWA BY EARLY THIS AFTERNOON...PER RUC 925 MB RH PROG. LIMITED DIURNAL
HEATING SHOULD ALSO HELP TO DISSIPATE THE LOWER CLOUDS.
HOWEVER...GIVEN THE TRENDS FROM THE LAST SEVERAL DAYS...CONFIDENCE
WITH THE TIMING OF CLEARING IS LOW AND CLEARING MAY BE DELAYED.
WAA AND SOME SUNSHINE SHOULD HELP BOOST TEMPS INTO THE LOWER 40S.
TONIGHT...WITH UPSTREAM DEWPOINTS INTO THE LOWER 30S AND MOISTURE
FROM MELTING SNOW OVER THE WEST...RADIATIONAL COOLING WILL LEAD TO
AREAS OF FOG OVER INLAND LOCATIONS AS MIN TEMPS ALSO FALL INTO THE
LOWER 30S.
THURSDAY INTO FRIDAY...UNSEASONABLY MILD CONDITIONS WILL DEVELOP AS
SW WINDS BRING IN MUCH WARMER AIR. WITH 925 MB TEMPS CLIMBING TO
AROUND 10C...A VERY STRONG INVERSION WILL DEVELOP. MAX TEMPS WILL
DEPEND ON HOW QUICKLY ANY MORNING FOG/STRATUS BURNS OFF AND THE
MIXING DEPTH. EVEN WITH LATE NOV SUN ANGLE AND A VERY STABLE SFC-900
MB LAYER...EXPECT ENOUGH MIXING FOR TEMPS ABOVE CONS GUIDANCE
VALUES...CLIMBING TO AROUND 50. AREAS WITH DOWNSLOPE SW WINDS SHOULD
SEE READINGS INTO AT LEAST THE MID 50S. THIS MAY END UP JUST A BIT
SHORT OF THE 55 DEGREE RECORD FROM 1984 AT NWS MQT. MIN TEMPS WILL
ALSO REMAIN WELL ABOVE NORMAL THU NIGHT WITH READINGS INT THE UPPER
30S TO AROUND 40. INCREASING CLOUDS AS WEAK TROUGH/FRONT SAGS INTO
THE AREA WILL KEEP MAX TEMPS IN THE 40S.
SATURDAY...THE GFS/ECMWF WERE IN REASONABLE AGREEMENT WITH THE
PROGRESSIVE MID LEVEL TROUGH AND THE SFC LOW DEVELOPING OVER THE
PLAINS AND MOVING INTO WRN WI BY 12Z SAT. STRONG MOISTURE INFLOW
WITH PWAT VALUES TO 0.75-1.00 AND 295K-300K ISENTROPIC LIFT AHEAD OF
THE LOW SUPPORT LIKELY RAIN CHANCES OVER THE AREA. MODELS SUGGEST
THAT CAA IN THE WAKE OF THE LOW WILL BE STRONG ENOUGH FOR A
CHANGEOVER TO SNOW AND POSSIBLY LAKE ENHANCED SNOW LATE SAT NIGHT
INTO SUN MORNING.
SUN-TUE...GFS/ECWMF AND RESPECTIVE ENSEMBLES SOLUTIONS SPREAD BECOMES
VERY LARGE AS MODELS HAVE DIFFICULTY DETERMING WHETHER A CUTOFF SRN
STREAM LOW WILL DEVELOP AND WHERE IT WILL MOVE. WITH LOW CONFIDENCE
IN ANY PARTICULAR SCENARIO...FCST INCLUDES CHANCE RAIN/SNOW POPS FOR
POSSIBITILITY THAT THE CUTOFF LOW MAY MOVE BACK CLOSE ENOUGH TO
SPREAD PCPN (DETERMINISTIC FCSTS EVEN HAVE AMOUNTS AOA AN INCH) BACK
INTO THE WRN LAKES...PER 00Z/23 GFS AND 12Z/22 ECMWF. OTHER SOLUTION
CLUSTERS THAT FAVOR A MORE PROGRESSIVE TROUGH OR A CUTOFF MUCH
FARTHER SOUTH WOULD BRING DRY AND CONTINUED MILD WEATHER TO THE AREA.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
AS HAS BEEN THE CASE OVER THE LAST COUPLE DAYS...MVFR/IFR CLOUDS
CONTINUE TO BE THE CONCERN FOR THE TAF FORECASTS. CONFIDENCE IN
FORECAST CONTINUES TO BE LOW AS WELL AS DOWNSLOPING POCKETS HAVE
OPENED HOLES IN THE CLOUDS. THINKING INCREASED DAYTIME MIXING AND
DRIER AIR OVER WRN MN WILL SCATTER THE CLOUDS OUT THIS AFTERNOON
BEFORE REDEVELOPMENT WITH THE LOW CLOUDS AND FOG OCCURS AFTER SUNSET.
WILL CONTINUE TO GO WITH PERSISTENCE FOR THE FORECAST AND HAVE
CONDITIONS IMPROVING TO VFR THIS AFTERNOON...AND THEN QUICKLY
DETERIORATE TO IFR THIS EVENING WITH REDEVELOPMENT OCCURING. LOOKS
LIKE ON THU MORNING...DRY ENOUGH AIR ARRIVES TO SCOUT THE LOW CLOUDS
AND FOG OUT ONCE AND FOR ALL WITH STRONGER WINDS ARRIVING. DID PUT
LLWS IN ALL SITES AS STRONG WINDS DEVELOP TONIGHT ABOVE INVERSION.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
HIGH PRESSURE RIDGE CURRENTLY OVER LAKE SUPERIOR WILL SHIFT EAST
TODAY AS A LOW MOVES THROUGH SOUTHERN CANADA. THIS WILL LEAD TO
INCREASING SOUTHWESTERLY WINDS TODAY...INCLUDING A FEW GALE FORCE
GUSTS TO 35 KNOTS THIS AFTN NEAR ISLE ROYALE BEFORE THE INVERSION
INTENSIFIES TONIGHT. WITH THE HIGH OVER THE SERN U.S. AND A SECOND
LOW MOVING THROUGH SOUTHERN CANADA TONIGHT INTO THURSDAY
NIGHT...EXPECT SOUTHWEST WINDS OF 15-25KTS TO CONTINUE. A SURFACE
TROUGH WILL SLIDE OVER LAKE SUPERIOR ON FRIDAY...DIMINISHING THE
SOUTHEASTERLY WINDS BELOW 15KTS. THIS TROUGH WILL LAY THE FOUNDATION
FOR A LOW DEVELOPING OVER THE CENTRAL PLAINS ON FRIDAY AND MOVING
INTO THE UPPER GREAT LAKES BY SATURDAY NIGHT. THIS COULD PRODUCE A
FEW NORTH-NORTHWEST GALES TO 35KTS SAT NIGHT INTO SUN MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
631 AM EST WED NOV 23 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL RIDGE
OVER THE WRN CONUS GRADUALLY EXPANDING TOWARD THE WRN GREAT LAKES. A
SHRTWV ATOP THE RIDGE WAS MOVING THROUGH CNTRL MANITOBA. AT THE
SFC...A RIDGE PERSITED OVER THE WRN LAKES BTWN A 997 MB LOW NEAR
LAKE WINNIPEG AND A 1001 MB LOW OVER NW PA. WRLY 925-900 MB WINDS
WERE HELPING TO PUSH A STRATUS DECK EASTWARD THROUGH CENTRL UPPER
MI.
&&
.DISCUSSION
TODAY...EXPECT THAT AS THE MANITOBA LOW PRES SLIDS OFF TO THE EAST
THROUGH NRN ONTARIO...THE INCREASING WRLY LOW LEVEL FLOW WILL BRING
THE BACK EDGE OF THE CLOUD DECK(CURRENTLY OVER NW MN) THROUGH THE
CWA BY EARLY THIS AFTERNOON...PER RUC 925 MB RH PROG. LIMITED DIURNAL
HEATING SHOULD ALSO HELP TO DISSIPATE THE LOWER CLOUDS.
HOWEVER...GIVEN THE TRENDS FROM THE LAST SEVERAL DAYS...CONFIDENCE
WITH THE TIMING OF CLEARING IS LOW AND CLEARING MAY BE DELAYED.
WAA AND SOME SUNSHINE SHOULD HELP BOOST TEMPS INTO THE LOWER 40S.
TONIGHT...WITH UPSTREAM DEWPOINTS INTO THE LOWER 30S AND MOISTURE
FROM MELTING SNOW OVER THE WEST...RADIATIONAL COOLING WILL LEAD TO
AREAS OF FOG OVER INLAND LOCATIONS AS MIN TEMPS ALSO FALL INTO THE LOWER
30S.
THURSDAY INTO FRIDAY...UNSEASONABLY MILD CONDITIONS WILL DEVELOP AS
SW WINDS BRING IN MUCH WARMER AIR. WITH 925 MB TEMPS CLIMBING TO
AROUND 10C...A VERY STRONG INVERSION WILL DEVELOP. MAX TEMPS WILL
DEPEND ON HOW QUICKLY ANY MORNING FOG/STRATUS BURNS OFF AND THE
MIXING DEPTH. EVEN WITH LATE NOV SUN ANGLE AND A VERY STABLE SFC-900
MB LAYER...EXPECT ENOUGH MIXING FOR TEMPS ABOVE CONS GUIDANCE
VALUES...CLIMBING TO AROUND 50. AREAS WITH DOWNSLOPE SW WINDS SHOULD
SEE READINGS INTO AT LEAST THE MID 50S. THIS MAY END UP JUST A BIT
SHORT OF THE 55 DEGREE RECORD FROM 1984 AT NWS MQT. MIN TEMPS WILL
ALSO REMAIN WELL ABOVE NORMAL THU NIGHT WITH READINGS INT THE UPPER
30S TO AROUND 40. INCREASING CLOUDS AS WEAK TROUGH/FRONT SAGS INTO
THE AREA WILL KEEP MAX TEMPS IN THE 40S.
SATURDAY...THE GFS/ECMWF WERE IN REASONABLE AGREEMENT WITH THE
PROGRESSIVE MID LEVEL TROUGH AND THE SFC LOW DEVELOPING OVER THE
PLAINS AND MOVING INTO WRN WI BY 12Z SAT. STRONG MOISTURE INFLOW
WITH PWAT VALUES TO 0.75-1.00 AND 295K-300K ISENTROPIC LIFT AHEAD OF
THE LOW SUPPORT LIKELY RAIN CHANCES OVER THE AREA. MODELS SUGGEST
THAT CAA IN THE WAKE OF THE LOW WILL BE STRONG ENOUGH FOR A
CHANGEOVER TO SNOW AND POSSIBLY LAKE ENHANCED SNOW LATE SAT NIGHT
INTO SUN MORNING.
SUN-TUE...GFS/ECWMF AND RESPECTIVE ENSEMBLES SOLUTIONS SPREAD BECOMES
VERY LARGE AS MODELS HAVE DIFFICULTY DETERMING WHETHER A CUTOFF SRN
STREAM LOW WILL DEVELOP AND WHERE IT WILL MOVE. WITH LOW CONFIDENCE
IN ANY PARTICULAR SCENARIO...FCST INCLUDES CHANCE RAIN/SNOW POPS FOR
POSSIBITILITY THAT THE CUTOFF LOW MAY MOVE BACK CLOSE ENOUGH TO
SPREAD PCPN (DETERMINISTIC FCSTS EVEN HAVE AMOUNTS AOA AN INCH) BACK
INTO THE WRN LAKES...PER 00Z/23 GFS AND 12Z/22 ECMWF. OTHER SOLUTION
CLUSTERS THAT FAVOR A MORE PROGRESSIVE TROUGH OR A CUTOFF MUCH
FARTHER SOUTH WOULD BRING DRY AND CONTINUED MILD WEATHER TO THE AREA.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
AS HAS BEEN THE CASE OVER THE LAST COUPLE DAYS...MVFR/IFR CLOUDS
CONTINUE TO BE THE CONCERN FOR THE TAF FORECASTS. BROAD AREA OF
CLOUDS SLID BACK OVER THE AREA THIS EVENING AND SHOULD CONTINUE INTO
THE FIRST PART OF THE AFTN. THINKING INCREASED DAYTIME MIXING AND
DRIER AIR OVER WRN MN WILL SCATTER THE CLOUDS OUT. IF THEY DON/T
CLEAR OUT HEADING INTO TONIGHT...WOULD LIKELY SEE THEM SETTLE IN
THROUGH THE PERIOD. IF SKIES CLEAR OUT...COULD SEE SOME FOG OVER
KSAW. KIWD/KCMX WILL BE LESS LIKELY WITH STRONGER WINDS AS HIGH
PRESSURE RIDGE SHIFTS EAST.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
HIGH PRESSURE RIDGE CURRENTLY OVER LAKE SUPERIOR WILL SHIFT EAST
TODAY AS A LOW MOVES THROUGH SOUTHERN CANADA. THIS WILL LEAD TO
INCREASING SOUTHWESTERLY WINDS TODAY...INCLUDING A FEW GALE FORCE
GUSTS TO 35 KNOTS THIS AFTN NEAR ISLE ROYALE BEFORE THE INVERSION
INTENSIFIES TONIGHT. WITH THE HIGH OVER THE SERN U.S. AND A SECOND
LOW MOVING THROUGH SOUTHERN CANADA TONIGHT INTO THURSDAY
NIGHT...EXPECT SOUTHWEST WINDS OF 15-25KTS TO CONTINUE. A SURFACE
TROUGH WILL SLIDE OVER LAKE SUPERIOR ON FRIDAY...DIMINISHING THE
SOUTHEASTERLY WINDS BELOW 15KTS. THIS TROUGH WILL LAY THE FOUNDATION
FOR A LOW DEVELOPING OVER THE CENTRAL PLAINS ON FRIDAY AND MOVING
INTO THE UPPER GREAT LAKES BY SATURDAY NIGHT. THIS COULD PRODUCE A
FEW NORTH-NORTHWEST GALES TO 35KTS SAT NIGHT INTO SUN MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
546 AM EST WED NOV 23 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL RIDGE
OVER THE WRN CONUS GRADUALLY EXPANDING TOWARD THE WRN GREAT LAKES. A
SHRTWV ATOP THE RIDGE WAS MOVING THROUGH CNTRL MANITOBA. AT THE
SFC...A RIDGE PERSITED OVER THE WRN LAKES BTWN A 997 MB LOW NEAR
LAKE WINNIPEG AND A 1001 MB LOW OVER NW PA. WRLY 925-900 MB WINDS
WERE HELPING TO PUSH A STRATUS DECK EASTWARD THROUGH CENTRL UPPER
MI.
&&
.DISCUSSION
TODAY...EXPECT THAT AS THE MANITOBA LOW PRES SLIDS OFF TO THE EAST
THROUGH NRN ONTARIO...THE INCREASING WRLY LOW LEVEL FLOW WILL BRING
THE BACK EDGE OF THE CLOUD DECK(CURRENTLY OVER NW MN) THROUGH THE
CWA BY EARLY THIS AFTERNOON...PER RUC 925 MB RH PROG. LIMITED DIURNAL
HEATING SHOULD ALSO HELP TO DISSIPATE THE LOWER CLOUDS.
HOWEVER...GIVEN THE TRENDS FROM THE LAST SEVERAL DAYS...CONFIDENCE
WITH THE TIMING OF CLEARING IS LOW AND CLEARING MAY BE DELAYED.
WAA AND SOME SUNSHINE SHOULD HELP BOOST TEMPS INTO THE LOWER 40S.
TONIGHT...WITH UPSTREAM DEWPOINTS INTO THE LOWER 30S AND MOISTURE
FROM MELTING SNOW OVER THE WEST...RADIATIONAL COOLING WILL LEAD TO
AREAS OF FOG OVER INLAND LOCATIONS AS MIN TEMPS ALSO FALL INTO THE LOWER
30S.
THURSDAY INTO FRIDAY...UNSEASONABLY MILD CONDITIONS WILL DEVELOP AS
SW WINDS BRING IN MUCH WARMER AIR. WITH 925 MB TEMPS CLIMBING TO
AROUND 10C...A VERY STRONG INVERSION WILL DEVELOP. MAX TEMPS WILL
DEPEND ON HOW QUICKLY ANY MORNING FOG/STRATUS BURNS OFF AND THE
MIXING DEPTH. EVEN WITH LATE NOV SUN ANGLE AND A VERY STABLE SFC-900
MB LAYER...EXPECT ENOUGH MIXING FOR TEMPS ABOVE CONS GUIDANCE
VALUES...CLIMBING TO AROUND 50. AREAS WITH DOWNSLOPE SW WINDS SHOULD
SEE READINGS INTO AT LEAST THE MID 50S. THIS MAY END UP JUST A BIT
SHORT OF THE 55 DEGREE RECORD FROM 1984 AT NWS MQT. MIN TEMPS WILL
ALSO REMAIN WELL ABOVE NORMAL THU NIGHT WITH READINGS INT THE UPPER
30S TO AROUND 40. INCREASING CLOUDS AS WEAK TROUGH/FRONT SAGS INTO
THE AREA WILL KEEP MAX TEMPS IN THE 40S.
SATURDAY...THE GFS/ECMWF WERE IN REASONABLE AGREEMENT WITH THE
PROGRESSIVE MID LEVEL TROUGH AND THE SFC LOW DEVELOPING OVER THE
PLAINS AND MOVING INTO WRN WI BY 12Z SAT. STRONG MOISTURE INFLOW
WITH PWAT VALUES TO 0.75-1.00 AND 295K-300K ISENTROPIC LIFT AHEAD OF
THE LOW SUPPORT LIKELY RAIN CHANCES OVER THE AREA. MODELS SUGGEST
THAT CAA IN THE WAKE OF THE LOW WILL BE STRONG ENOUGH FOR A
CHANGEOVER TO SNOW AND POSSIBLY LAKE ENHANCED SNOW LATE SAT NIGHT
INTO SUN MORNING.
SUN-TUE...GFS/ECWMF AND RESPECTIVE ENSEMBLES SOLUTIONS SPREAD BECOMES
VERY LARGE AS MODELS HAVE DIFFICULTY DETERMING WHETHER A CUTOFF SRN
STREAM LOW WILL DEVELOP AND WHERE IT WILL MOVE. WITH LOW CONFIDENCE
IN ANY PARTICULAR SCENARIO...FCST INCLUDES CHANCE RAIN/SNOW POPS FOR
POSSIBITILITY THAT THE CUTOFF LOW MAY MOVE BACK CLOSE ENOUGH TO
SPREAD PCPN (DETERMINISTIC FCSTS EVEN HAVE AMOUNTS AOA AN INCH) BACK
INTO THE WRN LAKES...PER 00Z/23 GFS AND 12Z/22 ECMWF. OTHER SOLUTION
CLUSTERS THAT FAVOR A MORE PROGRESSIVE TROUGH OR A CUTOFF MUCH
FARTHER SOUTH WOULD BRING DRY AND CONTINUED MILD WEATHER TO THE AREA.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
CHALLENGING FCST SHAPING FOR AT LEAST THE FIRST HALF OF THIS FCST
PERIOD. SHALLOW MOISTURE TRAPPED UNDER INVERSION CONTINUES TO RESULT
IN MVFR CIGS ACROSS THE UPPER LAKES. HOWEVER...THERE ARE SIGNIFICANT
HOLES...WITH LOCAL DOWNSLOPING CONTRIBUTING. CIGS AT KCMX MAY
SCATTER OUT IF DOWNSLOPING OFF THE HURON MTNS IN LIGHT SSE FLOW
STRENGTHENS SUFFICIENTLY. AT KSAW...WOULD EXPECT MVFR CIGS TO
PREVAIL INTO AT LEAST THE MORNING HRS AS LIGHT SSE UPSLOPE FLOW
DEVELOPS.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
HIGH PRESSURE RIDGE CURRENTLY OVER LAKE SUPERIOR WILL SHIFT EAST
TODAY AS A LOW MOVES THROUGH SOUTHERN CANADA. THIS WILL LEAD TO
INCREASING SOUTHWESTERLY WINDS TODAY...INCLUDING A FEW GALE FORCE
GUSTS TO 35 KNOTS THIS AFTN NEAR ISLE ROYALE BEFORE THE INVERSION
INTENSIFIES TONIGHT. WITH THE HIGH OVER THE SERN U.S. AND A SECOND
LOW MOVING THROUGH SOUTHERN CANADA TONIGHT INTO THURSDAY
NIGHT...EXPECT SOUTHWEST WINDS OF 15-25KTS TO CONTINUE. A SURFACE
TROUGH WILL SLIDE OVER LAKE SUPERIOR ON FRIDAY...DIMINISHING THE
SOUTHESTERLY WINDS BELOW 15KTS. THIS TROUGH WILL LAY THE FOUNDATION
FOR A LOW DEVELOPING OVER THE CENTRAL PLAINS ON FRIDAY AND MOVING
INTO THE UPPER GREAT LAKES BY SATURDAY NIGHT. THIS COULD PRODUCE A
FEW NORTH-NORTHWEST GALES TO 35KTS SAT NIGHT INTO SUN MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...ROLFSON
MARINE...SRF
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
715 AM EST WED NOV 23 2011
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS THE AREA FROM THE WEST THIS
AFTERNOON...FOLLOWED BY A SECONDARY TROUGH FROM THE NORTH
TONIGHT. STRONG COOL HIGH PRES WILL BUILD OVER THE REGION THU
INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 645 AM WEDNESDAY...SHOWERS AND ISOLD TSTMS MOVING ACROSS AREA
WILL HOLD TOGETHER FOR ERN HALF OF AREA NEXT FEW HOURS...AND RAISED
POPS TO CATEGORICAL E OF HWY 17. ISOLD SVR THREAT WILL PERSIST WITH
50 KT WINDS INDICATED AT 2K FEET BUT CELLS HAVE NOT BEEN DEEP ENOUGH
TO MIX DOWN STRONGER WINDS. KEPT LIKELY POPS ALONG COAST EARLY AFTN
UNTIL FRONT PASSES BUT 06Z NAM12 IS INDICATING PCPN ALL OFFSHORE BY
18Z. NO CHANGES TO TEMPS.
/PREVIOUS DISCUSSION/
AS OF 300 AM WEDNESDAY...LEADING EDGE OF PRE-FRONTAL BAND OF SHOWERS
JUST W OF COASTAL PLAINS WHILE SCT ACTIVITY JUST OFFSHORE TO S.
INITIAL ACTIVITY WILL PRODUCE DECENT PCPN COVERAGE 4 AM-7 AM AND
HAVE RAISED POPS ACCORDINGLY FOR WRN AND SRN SECTIONS. NO LIGHTNING
OBSERVED UPSTREAM PAST HOUR OR SO AND WILL KEEP TSTM MENTION AS
ISOLATED. SVR THREAT LOOKS MARGINAL AS WIND FIELDS ARE IMPRESSIVE
BUT INSTABILITY WEAK. WILL GO WITH SOME CATEGORICAL POPS EARLY THIS
MORNING BUT CAP AT LIKELY AFTER 7 AM DUE TO RECENT MODEL TRENDS
SUPPORTED BY RADAR. LATEST NAM12 AND RUC13 ARE INDICATING ACTIVITY
DEVELOPING JUST OFFSHORE 7 AM-10 AM WITH ACTIVITY OVER LAND
DIMINISHING...WHICH IS FREQUENTLY SEEN AS OFFSHORE ACTION LIMITS
INFLOW OVER LAND. ALSO REDUCED POPS REST OF DAY AS FRONT MOVING A
LITTLE FASTER. RAISED MAX TEMPS A FEW DEGS IN LINE WITH LATEST MOS
GDNC.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS OF 300 AM WEDNESDAY...MAIN CHANGE TO PREVIOUS FCST WAS TO GO WITH
MORE CLOUDS OVERNIGHT WITH MODELS INDICATING COLD AIR SCU WITH
SECONDARY SHRT WV. KEPT 20-30 POPS FOR NE HALF OF AREA FOR PSBL
LIGHT SHOWERS WITH THIS ACTIVITY. MOS BLEND FOR MIN TEMPS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 250 AM WED...VERY QUIET START TO THE PERIOD AND THROUGH THE
WEEKEND AS SFC HIGH PRESSURE AND UPPER RIDGE BUILD OVER THE EAST
COAST. LOW LEVEL THICKNESS VALUES AND NORTHERLY FLOW SUPPORT HIGHS
THU IN THE UPPER 50S TO LOWER 60S. GOOD RADIATIONAL COOLING SETUP
EXPECTED FOR THU NIGHT WITH CLEAR SKIES AND LIGHT
WINDS...RESULTING IN OVERNIGHT LOWS IN THE 30S INLAND AND
LOWER/MID 40S FOR THE OUTER BANKS. GRADUAL WARM UP EXPECTED FOR
FRI INTO THE WEEKEND AS UPPER HEIGHTS BUILD...WITH HIGHS LIKELY IN
THE MID/UPPER 60S. HIGH PRESSURE WILL MOVE OFFSHORE LATE SAT NIGHT
INTO SUN AHEAD OF NEXT APPROACHING SYSTEM. MODELS COMING INTO
BETTER AGREEMENT THAT THE TROUGH WILL BECOME CUT-OFF INVOF THE MID
MISSISSIPPI RIVER VALLEY LATE SUN INTO MON BUT TIMING AND DETAIL
OF THE MOVEMENT OF CUT-OFF LOWS IS ALWAYS TOUGH TO PREDICT
BRINGING HIGHER THAN NORMAL UNCERTAINTY WITH THIS NEXT SYSTEM.
WILL CONTINUE TO FOLLOW CLOSE TO HPC GUIDANCE WITH BEST CHANCE OF
SHOWERS ARRIVING MON AND LINGERING INTO TUE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
/SHORT TERM TODAY AND TONIGHT/...
AS OF 630 AM WEDNESDAY...SHOWERS AND ISOLD TSTMS CURRENTLY AFFECTING
AREA WITH MVFR AND LCL IFR WILL CONTINUE MOVING E THIS
MORNING...WITH LINGERING SCT THREAT INTO EARLY AFTN. VFR EXPECTED
LATE MORNING THROUGH AFTN BUT GUSTY WINDS WILL PERSIST INTO
EVENING...WITH SW BECOMING W THIS AFTN AND SHIFTING TO NW LATE. SOME
COLD AIR SCU LIKELY OVERNIGHT WITH SECONDARY SHRT WV...AND EXPECT A
PERIOD OF CIGS NEAR 3K FT...THEN CLEARING LATE.
/LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 AM WED...PREDOMINATE VFR CONDITIONS EXPECTED THROUGH THE
PERIOD...THOUGH COULD SEE EACH MORNING WITH CLEAR SKIES AND LIGHT
WINDS...BEST CHANCES WILL LIKELY BE SAT AND SUN MORNINGS AS RETURN
FLOW AROUND THE SFC HIGH DEVELOPS.
&&
.MARINE...
/SHORT TERM TODAY AND TONIGHT/..
AS OF 700 AM WEDNESDAY...STRONGER SW WINDS HAVE DEVELOPED AS
EXPECTED AHEAD OF FRONT AND SEAS ARE BUILDING AS WELL WITH 8 FT
OBSERVED AT 41036. FCST ON TRACK WITH SCA ALL AREAS THROUGH TONIGHT
WITH GALES EXPECTED WITH CAA SURGE N OF OCRACOKE INLET TONIGHT.
/LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 AM WED...FREQUENT WIND GUSTS TO GALE FORCE WILL LIKELY
CONTINUE THROUGH MID MORNING THU NORTH OF OCRACOKE. WINDS WILL
GRADUALLY DIMINISH LATE THURSDAY MORNING AND CONTINUE THROUGH THE
DAY AS HIGH PRESSURE BUILDS EASTWARD. AT THIS TIME HAVE SEAS PEAKING
THURSDAY MORNING AT 8-11FT NORTH OF OCRACOKE AND 5-8FT SOUTH. NORTH
OF CAPE HATTERAS COULD SEE A BRIEF PERIOD OF HIGH SURF CONDITIONS
THURSDAY MORNING WITH POTENTIAL FOR MINOR OCEAN OVERWASH...THOUGH
WILL BE CLOSE AND WILL LET LATER SHIFTS RE-EVALUATE. TWEAKED SCA END
TIMES SLIGHTLY BASED ON LATEST SWAN/WAVEWATCH RUNS. SEAS WILL
CONTINUE TO SUBSIDE LATE THU NIGHT INTO FRI.
HIGH PRESSURE WILL CONTINUE TO BUILD E OVER THE REGION FRI THROUGH
THE WEEKEND RESULTING IN BENIGN BOATING CONDITIONS. WINDS
GENERALLY 15KT OR LESS AND SEAS 2-4FT. HIGH WILL MOVE OFFSHORE
LATE SAT NIGHT INTO SUN RESULTING IN FLOW BECOMING PREDOMINATELY
S/SE.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR AMZ135.
SMALL CRAFT ADVISORY UNTIL 3 PM EST THURSDAY FOR AMZ130.
GALE WARNING FROM 11 PM THIS EVENING TO 10 AM EST THURSDAY FOR
AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL 1 AM EST FRIDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...SK/CQD
AVIATION...JBM/CQD
MARINE...JBM/CQD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
645 AM EST WED NOV 23 2011
.SYNOPSIS...
RAIN SHOWERS AND A FEW THUNDERSTORMS CAN BE EXPECTED TODAY AS A
COLD FRONT MOVES ACROSS THE AREA...FOLLOWED BY CLEARING AND COOLER
CONDITIONS INTO THANKSGIVING DAY. TEMPERATURES WILL WARM INTO THE
WEEKEND AS HIGH PRESSURE MOVES OFFSHORE. AN APPROACHING UPPER LOW
PRESSURE SYSTEM WILL BRING UNSETTLED WEATHER TO THE REGION SUNDAY
AND MONDAY. A COLD FRONT MAY IMPACT THE EASTERN CAROLINAS MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...BACK EDGE OF THE AREA OF CONVECTION...
RATHER THAN A LINE...IS NOW TRACKING ACROSS THE WESTERN PORTIONS OF
THE ILM CWA. THE INDIVIDUAL ELEMENTS WITHIN THIS AREA CONTINUE TO
RACE TO THE NE AT 35 TO 45 MPH. BY 10AM...THE MAIN AREA OF
CONVECTION SHOULD BE OFF THE CAROLINA COASTS WITH ONLY RESIDUAL AND
ISOLATED -SHRA TO CONTEND WITH OVER LAND UNTIL THE PASSAGE OF THE
COLD FRONT ITSELF BY NOON-1 PM. LATEST HRRR MODEL WAS A BIG HELP IN
DETERMINING THE COLD FRONTAL POSITIONING/MOVEMENT. SFC BASED
INSTABILITY IS OF LITTLE HELP TO THIS CONVECTION ESPECIALLY WITH
LACK OF INSOLATION. DIMINISHING THREAT FROM THE LOW LEVEL JET
KINEMATICS FROM A 50+ KNOT LOW LEVEL JET...BEST SEEN USING 925MB
PROGS. WILL CONTINUE THE THREAT FOR STRONG WIND GUSTS IN THE
HWO...IE. 30-45 MPH FROM ANY OF THE ISOLATED STRONG STORMS.
THE LATEST NAM AND HRRR INDICATE S WINDS BECOMING SW AFTER THE
PASSAGE OF THIS CONVECTION...IE. SIMILAR TO THAT OF A PRE-FRONTAL
TROF. THE COLD FRONTAL PASSAGE TO OCCUR DURING THE EARLY AFTERNOON
TIME FRAME. FOLLOWED BY COLD AIR ADVECTION DELIVERED WITH GUSTY NW
WINDS THROUGH TONIGHT. PARTIAL CLEARING WILL OCCUR THIS AFTERNOON...
WITH COMPLETELY CLEAR SKIES OCCURRING OVERNIGHT ONCE THE PASSAGE OF
THE 5H VORT OFF THE DELMARVA COAST. GIVEN LATEST TRENDS...MAX TEMPS
TO OCCUR BEFORE OR AROUND NOON...WITH TEMPS FALLING THROUGH THE
AFTERNOON. AS FOR MINS...CAA TO OCCUR ALL NIGHT WITH WINDS STAYING
ACTIVE PREVENTING ANY RADIATIONAL COOLING EFFECTS. HAVE LEANED
TOWARD THE HIGHER SIDE OF GUIDANCE FOR MINS TONIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 345 PM WEDNESDAY...BY DAYBREAK THANKSGIVING BRISK COLD AIR
ADVECTION IS ALREADY UNDERWAY AS A COLD FRONT CONTINUES TO SWEEP
OFFSHORE. HENCE A BRIGHT AND COOL DAY ANTICIPATED THURSDAY WITH
MAXIMUM TEMPERATURES HOLDING PRIMARILY IN THE MIDDLE 60S. IDEAL
RADIATIONAL COOLING INTO PRE-DAWN FRIDAY MORNING AS HIGH PRESSURE
SETTLES OVERHEAD...AND SOME INTERIOR LOCATIONS TO SEE FREEZING
TEMPERATURES AT DAYBREAK FRIDAY. FRIDAY FAIR AND DRY...COMPARED
TO THANKSGIVING 4-6 DEGREES F MILDER...AND LOWER 70S ANTICIPATED.
IT APPEARS RADIATIONAL COOLING WILL REMAIN EFFICIENT FRIDAY NIGHT
AS HIGH PRESSURE CENTERED OFFSHORE EXTENDED INTO THE AREA...AND
MINS BY DAYBREAK SATURDAY SHOULD SEE WIDESPREAD LOW/MIDDLE 30S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 345 AM WEDNESDAY...TEMPERATURE MODERATION THE MAIN STORY OVER
THE WEEKEND. PROGRESSIVE RETURN FLOW AND THE APPROACH OF A CUTOFF
LOW OVER THE GULF STATES...MAY BRING SCATTERED CONVECTIVE RAIN AND
A FEW TSTMS SUNDAY AND MONDAY. THE UPPER LOW IS PROGGED BY BOTH
THE ECMWF/GFS TO LIFT NORTH AND WEST OF OUR WARNING AREA BY TUESDAY
ALLOWING DRY AIR TO WRAP AROUND THE SOUTHERN PORTIONS OF THE EXITING
UPPER LOW. THUS POP VALUES WERE REDUCED THROUGH TUESDAY. APPEARS A
COLD FRONT MAY IMPACT THE ARE NEXT WEDNESDAY. HAVE NOT INTRODUCED
POP VALUES OF MENTION SINCE MODEL DIVERGENCE BECOME SIGNIFICANT BY
DAY 7.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO
CREATE MVFR AND BRIEF IFR. AROUND MIDDAY...CONDITIONS WILL SLOWLY
IMPROVE WEST TO EAST TO VFR...CONTINUING THROUGH THE VALID PERIOD.
CURRENT RADAR DEPICTS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE ENTIRE CWA THIS MORNING AHEAD OF AN APPROACHING COLD
FRONT. THIS ACTIVITY WILL TO CONTINUE TO PROPAGATE EASTWARD...WITH A
BACK END OF THE SHRA/TSRA APPROACHING KFLO ATTM. BY
MIDDAY...CONDITIONS WILL IMPROVE WEST TO EAST...AS GUSTY WINDS
CONTINUE TO SWEEP ACROSS THE COASTAL PLAINS. SOUTHWEST WINDS WITH
GUSTS UP TO AROUND 30KTS ARE ANTICIPATED OVER THE NEXT FEW
HOURS...DECREASING SLIGHTLY BY THIS AFTERNOON. EXPECT A WINDSHIFT AS
WELL WITH THE FROPA...FROM SOUTHWEST THIS MORNING TO NORTH-NORTHWEST
THIS AFTERNOON THROUGH THE VALID PERIOD WITH WIND GUSTS SUBSIDING
THIS EVENING.
EXTENDED OUTLOOK...EXPECT VFR THROUGH PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...COOL STABLE AIR OVER THE NEARSHORE WATERS
HAS PREVENTING THE HIGHER WINDS JUST OFF THE DECK FROM MIXING TO THE
SFC. HOWEVER...THE SFC PG HAS TIGHTENED AHEAD OF THE APPROACHING
COLD FRONT ALLOWING SOUTH WINDS TO FINALLY INCREASE. THE HIGHER SEAS
ACROSS THE WATERS EARLY THIS MORNING ARE FROM HIGHER WAVES LEACHING
INTO THE ILM WATERS FROM OFFSHORE WHERE WINDS ALOFT HAVE BEEN ABLE
TO MIX DOWN TO THE OCEAN SFC DUE TO SSTS IN THE 70S.
PRE-FRONTAL TROF WILL ACCOMPANY THE PASSAGE OF THE CONVECTION THIS
MORNING...VEERING WINDS FROM SOUTH TO SOUTHWEST. SFC PG WILL FURTHER
TIGHTEN...WITH WINDS INCREASING TO 15-25 KT...WITH GUSTS UP TO 30
KT. THE COLD FRONTAL PASSAGE VIA NAM/HRRR TO OCCUR THIS
AFTERNOON...FURTHER VEERING WINDS TO WEST DURING THE AFTERNOON...AND
TO NORTHWEST TONIGHT. SFC PG REMAINS TIGHTENED AFTER FROPA BUT IS
NOW ACCOMPANIED BY COLD AIR ADVECTION. THIS WILL FURTHER INCREASE
WINDS TO 20 TO 30 KT...WITH FEW HIGHER GUSTS. THE GRADIENT WILL
RELAX SOME LATE TONIGHT BUT CAA WILL CONTINUE...WITH WIND SPEEDS
ONLY DROPPING TO 15-25 KT OVERNIGHT.
SEAS WILL BE DOMINATED BY WIND WAVES...WITH THE TEMPORARILY LONGER
FETCH THIS MORNING FROM S-SW WINDS AIDING SEA HEIGHTS IN THE 4 TO
8 FT RANGE...HIGHEST ACROSS THE SHOALS OFF CAPE FEAR. AVERAGE
PERIODS IN THE 5 TO 7 SECOND RANGE. THE MUCH SHORTER FETCH TONIGHT
UNDER OFFSHORE NW WINDS WILL DROP SEAS BACK TO THE 3 TO 6 FT
RANGE...WITH AVERAGE PERIODS IN THE 4 TO 6 SECOND RANGE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 345 AM WEDNESDAY...DAYBREAK THANKSGIVING WILL LIKELY BE
GREETED WITH SMALL CRAFT ADVISORIES IN BLUSTERY NW WIND FLOW MUCH
OF THE DAY AS A COLD FRONT BOLTS FARTHER OFFSHORE. NW-N WIND GUSTS
TO 25 KNOTS CAN BE EXPECTED MOST OF THE DAY...WITH ADVISORIES
LIKELY DROPPING LATE THURSDAY SOMETIME. SIGNIFICANTLY LIGHTER
WINDS FRIDAY AS HIGH PRESSURE AT THE SURFACE NEARS. THIS SHOULD
RESULT IN NEARLY FLAT SEAS FRIDAY WITH LITTLE LONGER PERIOD SWELL
IN THE MIX AND VERY MANAGEABLE BOATING WEATHER/CONDITIONS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 345 AM WEDNESDAY...THIS PERIOD BEGINS IDEAL...BUT ENDS QUITE
TURBULENT LATE IN THE PERIOD. NEAR CALM WIND CONDITIONS DAYBREAK
SATURDAY WITH HIGH PRESSURE SETTLED OVERHEAD OF THE 0-20NM COASTAL
WATERS...THUS DOCILE SEAS ANTICIPATED. RETURN WIND FLOW SAT NIGHT
WILL BRING INCREASING SOUTHERLY WINDS INTO SUNDAY...PARTICULARLY
DURING THE DAY SUNDAY AS A SURFACE LOW MOVES ACROSS GEORGIA INTO
THE WESTERN CAROLINAS. THIS WILL BRING ADVISORY OR NEAR ADVISORY
SOUTH WINDS TO OUR WATERS BY SUNDAY AFTERNOON OR NIGHT. STRONG
WINDS ARE EXPECTED INTO MONDAY AS THE SFC LOW PASSES WEST OF THE
WATERS TRACKING NORTHWARD.
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 6
PM EST THURSDAY FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...DCH
SHORT TERM...MJC
LONG TERM...MJC
AVIATION...SGL
AREA FORECAST DISCUSSION...CORRECTED
NWS NEWPORT/MOREHEAD CITY NC
434 AM EST WED NOV 23 2011
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS THE AREA FROM THE WEST THIS
AFTERNOON...FOLLOWED BY A SECONDARY TROUGH FROM THE NORTH
TONIGHT. STRONG COOL HIGH PRES WILL BUILD OVER THE REGION THU
INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 300 AM WEDNESDAY...LEADING EDGE OF PRE-FRONTAL BAND OF SHOWERS
JUST W OF COASTAL PLAINS WHILE SCT ACTIVITY JUST OFFSHORE TO S.
INITIAL ACTIVITY WILL PRODUCE DECENT PCPN COVERAGE 4 AM-7 AM AND
HAVE RAISED POPS ACCORDINGLY FOR WRN AND SRN SECTIONS. NO LIGHTNING
OBSERVED UPSTREAM PAST HOUR OR SO AND WILL KEEP TSTM MENTION AS
ISOLATED. SVR THREAT LOOKS MARGINAL AS WIND FIELDS ARE IMPRESSIVE
BUT INSTABILITY WEAK. WILL GO WITH SOME CATEGORICAL POPS EARLY THIS
MORNING BUT CAP AT LIKELY AFTER 7 AM DUE TO RECENT MODEL TRENDS
SUPPORTED BY RADAR. LATEST NAM12 AND RUC13 ARE INDICATING ACTIVITY
DEVELOPING JUST OFFSHORE 7 AM-10 AM WITH ACTIVITY OVER LAND
DIMINISHING...WHICH IS FREQUENTLY SEEN AS OFFSHORE ACTION LIMITS
INFLOW OVER LAND. ALSO REDUCED POPS REST OF DAY AS FRONT MOVING A
LITTLE FASTER. RAISED MAX TEMPS A FEW DEGS IN LINE WITH LATEST MOS
GDNC.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS OF 300 AM WEDNESDAY...MAIN CHANGE TO PREVIOUS FCST WAS TO GO WITH
MORE CLOUDS OVERNIGHT WITH MODELS INDICATING COLD AIR SCU WITH
SECONDARY SHRT WV. KEPT 20-30 POPS FOR NE HALF OF AREA FOR PSBL
LIGHT SHOWERS WITH THIS ACTIVITY. MOS BLEND FOR MIN TEMPS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 250 AM WED...VERY QUIET START TO THE PERIOD AND THROUGH THE
WEEKEND AS SFC HIGH PRESSURE AND UPPER RIDGE BUILD OVER THE EAST
COAST. LOW LEVEL THICKNESS VALUES AND NORTHERLY FLOW SUPPORT HIGHS
THU IN THE UPPER 50S TO LOWER 60S. GOOD RADIATIONAL COOLING SETUP
EXPECTED FOR THU NIGHT WITH CLEAR SKIES AND LIGHT
WINDS...RESULTING IN OVERNIGHT LOWS IN THE 30S INLAND AND
LOWER/MID 40S FOR THE OUTER BANKS. GRADUAL WARM UP EXPECTED FOR
FRI INTO THE WEEKEND AS UPPER HEIGHTS BUILD...WITH HIGHS LIKELY IN
THE MID/UPPER 60S. HIGH PRESSURE WILL MOVE OFFSHORE LATE SAT NIGHT
INTO SUN AHEAD OF NEXT APPROACHING SYSTEM. MODELS COMING INTO
BETTER AGREEMENT THAT THE TROUGH WILL BECOME CUT-OFF INVOF THE MID
MISSISSIPPI RIVER VALLEY LATE SUN INTO MON BUT TIMING AND DETAIL
OF THE MOVEMENT OF CUT-OFF LOWS IS ALWAYS TOUGH TO PREDICT
BRINGING HIGHER THAN NORMAL UNCERTAINTY WITH THIS NEXT SYSTEM.
WILL CONTINUE TO FOLLOW CLOSE TO HPC GUIDANCE WITH BEST CHANCE OF
SHOWERS ARRIVING MON AND LINGERING INTO TUE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
/SHORT TERM TONIGHT AND WEDNESDAY/...
AS OF 100 AM WEDNESDAY...LATEST OBS INDICATE SOME SCU 2K-4K FT
STARTING TO DEVELOPE WITH INCREASING SRLY FLOW...AND EXPECT PERIOD
OF MVFR CIGS IN PRE-FRONTAL ENVIRONMENT...WHILE WINDS WILL LIMIT
THREAT OF REDUCED VSBYS. SHWRS AND A FEW TSTMS MAY BEGIN TO AFFECT
AREA 08Z-10Z BUT WILL MAINLY MOVE ACROSS REGION 11Z-16Z WITH PERIOD
OF IFR VSBYS AND GUSTS TO 30 KT LIKELY WITH HEAVIEST ACTIVITY. WIND
SHIFT TO NW AND DECREASING CLOUDS DURING AFTN WITH FRONTAL PASSAGE.
SOME COLD AIR SCU LIKELY DURING EVENING WITH SECONDARY SHRT WV...AND
COULD SEE A PERIOD OF CIGS NEAR 3K FT INTO OVERNIGHT.
/LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 AM WED...PREDOMINATE VFR CONDITIONS EXPECTED THROUGH THE
PERIOD...THOUGH COULD SEE EACH MORNING WITH CLEAR SKIES AND LIGHT
WINDS...BEST CHANCES WILL LIKELY BE SAT AND SUN MORNINGS AS RETURN
FLOW AROUND THE SFC HIGH DEVELOPS.
&&
.MARINE...
/SHORT TERM TODAY AND TONIGHT/..
AS OF 300 AM WEDNESDAY...WINDS ON TRACK FOR SCA CONDITIONS ALL AREAS
BY MORNING AND ONLY MINOR CHANGES TO PREVIOUS FCST WINDS BASED ON
MODEL BLEND. STRONG CAA SURGE TONIGHT WILL LIKELY LEAD TO AT LEAST
FREQUENT GUSTS TO 35 KT NRN WATERS AND POSTED GALES. LATEST WW3 IN
GENERAL AGREEMENT WITH PREVIOUS FCST SEAS.
/LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 AM WED...FREQUENT WIND GUSTS TO GALE FORCE WILL LIKELY
CONTINUE THROUGH MID MORNING THU NORTH OF OCRACOKE. WINDS WILL
GRADUALLY DIMINISH LATE THURSDAY MORNING AND CONTINUE THROUGH THE
DAY AS HIGH PRESSURE BUILDS EASTWARD. AT THIS TIME HAVE SEAS PEAKING
THURSDAY MORNING AT 8-11FT NORTH OF OCRACOKE AND 5-8FT SOUTH. NORTH
OF CAPE HATTERAS COULD SEE A BRIEF PERIOD OF HIGH SURF CONDITIONS
THURSDAY MORNING WITH POTENTIAL FOR MINOR OCEAN OVERWASH...THOUGH
WILL BE CLOSE AND WILL LET LATER SHIFTS RE-EVALUATE. TWEAKED SCA END
TIMES SLIGHTLY BASED ON LATEST SWAN/WAVEWATCH RUNS. SEAS WILL
CONTINUE TO SUBSIDE LATE THU NIGHT INTO FRI.
HIGH PRESSURE WILL CONTINUE TO BUILD E OVER THE REGION FRI THROUGH
THE WEEKEND RESULTING IN BENIGN BOATING CONDITIONS. WINDS
GENERALLY 15KT OR LESS AND SEAS 2-4FT. HIGH WILL MOVE OFFSHORE
LATE SAT NIGHT INTO SUN RESULTING IN FLOW BECOMING PREDOMINATELY
S/SE.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR AMZ135.
SMALL CRAFT ADVISORY UNTIL 3 PM EST THURSDAY FOR AMZ130.
GALE WARNING FROM 11 PM THIS EVENING TO 10 AM EST THURSDAY FOR
AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL 1 AM EST FRIDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...SK/CQD
AVIATION...JBM/CQD
MARINE...JBM/CQD
CORRECTED FOR SYNOPSIS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
345 AM EST WED NOV 23 2011
.SYNOPSIS...
RAIN SHOWERS AND A FEW THUNDERSTORMS CAN BE EXPECTED TODAY AS A
COLD FRONT MOVES ACROSS THE AREA...FOLLOWED BY CLEARING AND COOLER
CONDITIONS INTO THANKSGIVING DAY. TEMPERATURES WILL WARM INTO THE
WEEKEND AS HIGH PRESSURE MOVES OFFSHORE. AN APPROACHING UPPER LOW
PRESSURE SYSTEM WILL BRING UNSETTLED WEATHER TO THE REGION SUNDAY
AND MONDAY. A COLD FRONT MAY IMPACT THE EASTERN CAROLINAS MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 345 AM WEDNESDAY...CONVECTION WELL AHEAD OF A COLD FRONT
BEGINNING TO TRACK ACROSS THE WESTERN PORTIONS OF THE ILM CWA. THE
BROKEN LINE OF CONVECTION IS MOVING EAST AT AROUND 25 MPH...WITH THE
INDIVIDUAL CELLS WITHIN THE LINE MOVING NORTHEAST AT 30 TO 45 MPH.
SFC BASED INSTABILITY IS OF LITTLE AID TO THIS CONVECTION ESPECIALLY
WITH LACK OF INSOLATION. THE LOW LEVEL JET KINEMATICS FROM A 50+
KNOT LOW LEVEL JET...BEST SEEN AT 925MB PROGS...WILL CONTINUE THE
THREAT FOR STRONG WIND GUSTS. ANY OF THE STRONGER UPDRAFT/DOWNDRAFT
COUPLETS COULD BRIEFLY TAP THOSE LOW LEVEL WINDS AND BRING THEM
BRIEFLY TO THE SFC. HOWEVER...THESE COUPLETS HAVE BEEN DIFFICULT TO
COME BY AT THE MOMENT...AND LIKELY WILL CONTINUE FOR THE REMAINDER
OF THIS ACTIVITY AS IT PUSHES OFF THE CAROLINA COASTS BY MIDDAY.
WILL HIGHLIGHT IN THE HWO FOR POSSIBLE STRONG WIND GUSTS OF 30-45
MPH FROM ANY OF THE ISOLATED STRONG STORMS.
THE LATEST NAM AND HRRR INDICATE S WINDS BECOMING SW AFTER THE
PASSAGE OF THIS CONVECTION...IE. SIMILAR TO WHAT OCCURS DURING A
PRE-FRONTAL TROF. THE COLD FRONTAL PASSAGE OCCURS DURING THE EARLY
TO MID AFTERNOON TIME FRAME. FOLLOWED BY COLD AIR ADVECTION
DELIVERED WITH GUSTY NW WINDS THROUGH TONIGHT. PARTIAL CLEARING WILL
OCCUR THIS AFTERNOON...WITH COMPLETELY CLEAR SKIES OCCURRING
OVERNIGHT ONCE THE PASSAGE OF THE 5H VORT OFF THE DELMARVA COAST.
GIVEN LATEST TRENDS...MAX TEMPS TO OCCUR BEFORE OR AROUND
NOON...WITH TEMPS FALLING THROUGH THE AFTERNOON. AS FOR MINS...
CAA TO OCCUR ALL NIGHT WITH WINDS STAYING ACTIVE PREVENTING ANY
RADIATIONAL COOLING EFFECTS. HAVE LEANED TOWARD THE HIGHER SIDE OF
GUIDANCE FOR MINS TONIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 345 PM WEDNESDAY...BY DAYBREAK THANKSGIVING BRISK COLD AIR
ADVECTION IS ALREADY UNDERWAY AS A COLD FRONT CONTINUES TO SWEEP
OFFSHORE. HENCE A BRIGHT AND COOL DAY ANTICIPATED THURSDAY WITH
MAXIMUM TEMPERATURES HOLDING PRIMARILY IN THE MIDDLE 60S. IDEAL
RADIATIONAL COOLING INTO PRE-DAWN FRIDAY MORNING AS HIGH PRESSURE
SETTLES OVERHEAD...AND SOME INTERIOR LOCATIONS TO SEE FREEZING
TEMPERATURES AT DAYBREAK FRIDAY. FRIDAY FAIR AND DRY...COMPARED
TO THANKSGIVING 4-6 DEGREES F MILDER...AND LOWER 70S ANTICIPATED.
IT APPEARS RADIATIONAL COOLING WILL REMAIN EFFICIENT FRIDAY NIGHT
AS HIGH PRESSURE CENTERED OFFSHORE EXTENDED INTO THE AREA...AND
MINS BY DAYBREAK SATURDAY SHOULD SEE WIDESPREAD LOW/MIDDLE 30S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 345 AM WEDNESDAY...TEMPERATURE MODERATION THE MAIN STORY OVER
THE WEEKEND. PROGRESSIVE RETURN FLOW AND THE APPROACH OF A CUTOFF
LOW OVER THE GULF STATES...MAY BRING SCATTERED CONVECTIVE RAIN AND
A FEW TSTMS SUNDAY AND MONDAY. THE UPPER LOW IS PROGGED BY BOTH
THE ECMWF/GFS TO LIFT NORTH AND WEST OF OUR WARNING AREA BY TUESDAY
ALLOWING DRY AIR TO WRAP AROUND THE SOUTHERN PORTIONS OF THE EXITING
UPPER LOW. THUS POP VALUES WERE REDUCED THROUGH TUESDAY. APPEARS A
COLD FRONT MAY IMPACT THE ARE NEXT WEDNESDAY. HAVE NOT INTRODUCED
POP VALUES OF MENTION SINCE MODEL DIVERGENCE BECOME SIGNIFICANT BY
DAY 7.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 08Z...ACTUAL COLD FRONTAL PASSAGE SLATED FOR MIDDAY TODAY.
PRE-FRONTAL TSRA/SHRA WILL RESULT IN A BRIEF IFR/LIFR
CEILING/VSBY...WITH POSSIBLE WIND GUSTS UP TO 25 TO 40 KT FROM THE
CONVECTION. WINDS TO VEER FROM S TO SW-W AFTER THE TROFS
PASSAGE...AND INCREASE TO 15KT WITH GUSTS UP TO 25 KT. LOOK FOR
CONVECTION TO EXIT THE COAST BY 14Z. THE COLD FRONTAL PASSAGE FROM
WEST TO EAST...IS SLATED FOR MIDDAY TODAY. COULD SEE A STRAY SHRA
ALONG THE ACTUAL FRONT WITH POSSIBLE IFR CEILINGS PRIOR TO ITS
PASSAGE. FOR POST FRONTAL CONDITIONS...EXPECT A QUICK IMPROVEMENT
TO VFR CEILINGS...WITH SKC COMMON BY SUNSET. GUSTY W TO NW WINDS
WITH 10-20KT SUSTAINED...WITH GUSTS UP TO 25 TO 30 KT DURING THE
AFTERNOON. WINDS TO DROP TO 10-15 KT AFTER SUNSET WITH GUSTS STILL
UP TO 20 KT DURING THE EVENING.
EXTENDED OUTLOOK...EXPECT VFR THROUGH PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 345 AM WEDNESDAY...COOL STABLE AIR OVER THE NEARSHORE WATERS
HAS PREVENTING THE HIGHER WINDS JUST OFF THE DECK FROM MIXING TO THE
SFC. HOWEVER...THE SFC PG HAS TIGHTENED AHEAD OF THE APPROACHING
COLD FRONT ALLOWING SOUTH WINDS TO FINALLY INCREASE. THE HIGHER SEAS
ACROSS THE WATERS EARLY THIS MORNING ARE FROM HIGHER WAVES LEACHING
INTO THE ILM WATERS FROM OFFSHORE WHERE WINDS ALOFT HAVE BEEN ABLE
TO MIX DOWN TO THE OCEAN SFC DUE TO SSTS IN THE 70S.
PRE-FRONTAL TROF WILL ACCOMPANY THE PASSAGE OF THE CONVECTION THIS
MORNING...VEERING WINDS FROM SOUTH TO SOUTHWEST. SFC PG WILL FURTHER
TIGHTEN...WITH WINDS INCREASING TO 15-25 KT...WITH GUSTS UP TO 30
KT. THE COLD FRONTAL PASSAGE VIA NAM/HRRR TO OCCUR THIS
AFTERNOON...FURTHER VEERING WINDS TO WEST DURING THE AFTERNOON...AND
TO NORTHWEST TONIGHT. SFC PG REMAINS TIGHTENED AFTER FROPA BUT IS
NOW ACCOMPANIED BY COLD AIR ADVECTION. THIS WILL FURTHER INCREASE
WINDS TO 20 TO 30 KT...WITH FEW HIGHER GUSTS. THE GRADIENT WILL
RELAX SOME LATE TONIGHT BUT CAA WILL CONTINUE...WITH WIND SPEEDS
ONLY DROPPING TO 15-25 KT OVERNIGHT.
SEAS WILL BE DOMINATED BY WIND WAVES...WITH THE TEMPORARILY LONGER
FETCH THIS MORNING FROM S-SW WINDS AIDING SEA HEIGHTS IN THE 4 TO
8 FT RANGE...HIGHEST ACROSS THE SHOALS OFF CAPE FEAR. AVERAGE
PERIODS IN THE 5 TO 7 SECOND RANGE. THE MUCH SHORTER FETCH TONIGHT
UNDER OFFSHORE NW WINDS WILL DROP SEAS BACK TO THE 3 TO 6 FT
RANGE...WITH AVERAGE PERIODS IN THE 4 TO 6 SECOND RANGE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 345 AM WEDNESDAY...DAYBREAK THANKSGIVING WILL LIKELY BE
GREETED WITH SMALL CRAFT ADVISORIES IN BLUSTERY NW WIND FLOW MUCH
OF THE DAY AS A COLD FRONT BOLTS FARTHER OFFSHORE. NW-N WIND GUSTS
TO 25 KNOTS CAN BE EXPECTED MOST OF THE DAY...WITH ADVISORIES
LIKELY DROPPING LATE THURSDAY SOMETIME. SIGNIFICANTLY LIGHTER
WINDS FRIDAY AS HIGH PRESSURE AT THE SURFACE NEARS. THIS SHOULD
RESULT IN NEARLY FLAT SEAS FRIDAY WITH LITTLE LONGER PERIOD SWELL
IN THE MIX AND VERY MANAGEABLE BOATING WEATHER/CONDITIONS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 345 AM WEDNESDAY...THIS PERIOD BEGINS IDEAL...BUT ENDS QUITE
TURBULENT LATE IN THE PERIOD. NEAR CALM WIND CONDITIONS DAYBREAK
SATURDAY WITH HIGH PRESSURE SETTLED OVERHEAD OF THE 0-20NM COASTAL
WATERS...THUS DOCILE SEAS ANTICIPATED. RETURN WIND FLOW SAT NIGHT
WILL BRING INCREASING SOUTHERLY WINDS INTO SUNDAY...PARTICULARLY
DURING THE DAY SUNDAY AS A SURFACE LOW MOVES ACROSS GEORGIA INTO
THE WESTERN CAROLINAS. THIS WILL BRING ADVISORY OR NEAR ADVISORY
SOUTH WINDS TO OUR WATERS BY SUNDAY AFTERNOON OR NIGHT. STRONG
WINDS ARE EXPECTED INTO MONDAY AS THE SFC LOW PASSES WEST OF THE
WATERS TRACKING NORTHWARD.
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 6
PM EST THURSDAY FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...DCH
SHORT TERM...MJC
LONG TERM...MJC
AVIATION...DL/DCH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
330 AM EST WED NOV 23 2011
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH OF THE REGION TONIGHT AS A STRONG
COLD FRONT SWEEPS EAST INTO EASTERN NORTH CAROLINA BY EARLY
WEDNESDAY AND OFFSHORE BY WEDNESDAY AFTERNOON. STRONG COOL HIGH
PRESSURE WILL BUILD ACROSS THE AREA THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL CROSS THE REGION MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 300 AM WEDNESDAY...LEADING EDGE OF PRE-FRONTAL BAND OF SHOWERS
JUST W OF COASTAL PLAINS WHILE SCT ACTIVITY JUST OFFSHORE TO S.
INITIAL ACTIVITY WILL PRODUCE DECENT PCPN COVERAGE 4 AM-7 AM AND
HAVE RAISED POPS ACCORDINGLY FOR WRN AND SRN SECTIONS. NO LIGHTNING
OBSERVED UPSTREAM PAST HOUR OR SO AND WILL KEEP TSTM MENTION AS
ISOLATED. SVR THREAT LOOKS MARGINAL AS WIND FIELDS ARE IMPRESSIVE
BUT INSTABILITY WEAK. WILL GO WITH SOME CATEGORICAL POPS EARLY THIS
MORNING BUT CAP AT LIKELY AFTER 7 AM DUE TO RECENT MODEL TRENDS
SUPPORTED BY RADAR. LATEST NAM12 AND RUC13 ARE INDICATING ACTIVITY
DEVELOPING JUST OFFSHORE 7 AM-10 AM WITH ACTIVITY OVER LAND
DIMINISHING...WHICH IS FREQUENTLY SEEN AS OFFSHORE ACTION LIMITS
INFLOW OVER LAND. ALSO REDUCED POPS REST OF DAY AS FRONT MOVING A
LITTLE FASTER. RAISED MAX TEMPS A FEW DEGS IN LINE WITH LATEST MOS
GDNC.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS OF 300 AM WEDNESDAY...MAIN CHANGE TO PREVIOUS FCST WAS TO GO WITH
MORE CLOUDS OVERNIGHT WITH MODELS INDICATING COLD AIR SCU WITH
SECONDARY SHRT WV. KEPT 20-30 POPS FOR NE HALF OF AREA FOR PSBL
LIGHT SHOWERS WITH THIS ACTIVITY. MOS BLEND FOR MIN TEMPS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 250 AM WED...VERY QUIET START TO THE PERIOD AND THROUGH THE
WEEKEND AS SFC HIGH PRESSURE AND UPPER RIDGE BUILD OVER THE EAST
COAST. LOW LEVEL THICKNESS VALUES AND NORTHERLY FLOW SUPPORT HIGHS
THU IN THE UPPER 50S TO LOWER 60S. GOOD RADIATIONAL COOLING SETUP
EXPECTED FOR THU NIGHT WITH CLEAR SKIES AND LIGHT
WINDS...RESULTING IN OVERNIGHT LOWS IN THE 30S INLAND AND
LOWER/MID 40S FOR THE OUTER BANKS. GRADUAL WARM UP EXPECTED FOR
FRI INTO THE WEEKEND AS UPPER HEIGHTS BUILD...WITH HIGHS LIKELY IN
THE MID/UPPER 60S. HIGH PRESSURE WILL MOVE OFFSHORE LATE SAT NIGHT
INTO SUN AHEAD OF NEXT APPROACHING SYSTEM. MODELS COMING INTO
BETTER AGREEMENT THAT THE TROUGH WILL BECOME CUT-OFF INVOF THE MID
MISSISSIPPI RIVER VALLEY LATE SUN INTO MON BUT TIMING AND DETAIL
OF THE MOVEMENT OF CUT-OFF LOWS IS ALWAYS TOUGH TO PREDICT
BRINGING HIGHER THAN NORMAL UNCERTAINTY WITH THIS NEXT SYSTEM.
WILL CONTINUE TO FOLLOW CLOSE TO HPC GUIDANCE WITH BEST CHANCE OF
SHOWERS ARRIVING MON AND LINGERING INTO TUE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
/SHORT TERM TONIGHT AND WEDNESDAY/...
AS OF 100 AM WEDNESDAY...LATEST OBS INDICATE SOME SCU 2K-4K FT
STARTING TO DEVELOPE WITH INCREASING SRLY FLOW...AND EXPECT PERIOD
OF MVFR CIGS IN PRE-FRONTAL ENVIRONMENT...WHILE WINDS WILL LIMIT
THREAT OF REDUCED VSBYS. SHWRS AND A FEW TSTMS MAY BEGIN TO AFFECT
AREA 08Z-10Z BUT WILL MAINLY MOVE ACROSS REGION 11Z-16Z WITH PERIOD
OF IFR VSBYS AND GUSTS TO 30 KT LIKELY WITH HEAVIEST ACTIVITY. WIND
SHIFT TO NW AND DECREASING CLOUDS DURING AFTN WITH FRONTAL PASSAGE.
SOME COLD AIR SCU LIKELY DURING EVENING WITH SECONDARY SHRT WV...AND
COULD SEE A PERIOD OF CIGS NEAR 3K FT INTO OVERNIGHT.
/LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 AM WED...PREDOMINATE VFR CONDITIONS EXPECTED THROUGH THE
PERIOD...THOUGH COULD SEE EACH MORNING WITH CLEAR SKIES AND LIGHT
WINDS...BEST CHANCES WILL LIKELY BE SAT AND SUN MORNINGS AS RETURN
FLOW AROUND THE SFC HIGH DEVELOPS.
&&
.MARINE...
/SHORT TERM TODAY AND TONIGHT/..
AS OF 300 AM WEDNESDAY...WINDS ON TRACK FOR SCA CONDITIONS ALL AREAS
BY MORNING AND ONLY MINOR CHANGES TO PREVIOUS FCST WINDS BASED ON
MODEL BLEND. STRONG CAA SURGE TONIGHT WILL LIKELY LEAD TO AT LEAST
FREQUENT GUSTS TO 35 KT NRN WATERS AND POSTED GALES. LATEST WW3 IN
GENERAL AGREEMENT WITH PREVIOUS FCST SEAS.
/LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 AM WED...FREQUENT WIND GUSTS TO GALE FORCE WILL LIKELY
CONTINUE THROUGH MID MORNING THU NORTH OF OCRACOKE. WINDS WILL
GRADUALLY DIMINISH LATE THURSDAY MORNING AND CONTINUE THROUGH THE
DAY AS HIGH PRESSURE BUILDS EASTWARD. AT THIS TIME HAVE SEAS PEAKING
THURSDAY MORNING AT 8-11FT NORTH OF OCRACOKE AND 5-8FT SOUTH. NORTH
OF CAPE HATTERAS COULD SEE A BRIEF PERIOD OF HIGH SURF CONDITIONS
THURSDAY MORNING WITH POTENTIAL FOR MINOR OCEAN OVERWASH...THOUGH
WILL BE CLOSE AND WILL LET LATER SHIFTS RE-EVALUATE. TWEAKED SCA END
TIMES SLIGHTLY BASED ON LATEST SWAN/WAVEWATCH RUNS. SEAS WILL
CONTINUE TO SUBSIDE LATE THU NIGHT INTO FRI.
HIGH PRESSURE WILL CONTINUE TO BUILD E OVER THE REGION FRI THROUGH
THE WEEKEND RESULTING IN BENIGN BOATING CONDITIONS. WINDS
GENERALLY 15KT OR LESS AND SEAS 2-4FT. HIGH WILL MOVE OFFSHORE
LATE SAT NIGHT INTO SUN RESULTING IN FLOW BECOMING PREDOMINATELY
S/SE.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR AMZ135.
SMALL CRAFT ADVISORY UNTIL 3 PM EST THURSDAY FOR AMZ130.
GALE WARNING FROM 11 PM THIS EVENING TO 10 AM EST THURSDAY FOR
AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL 1 AM EST FRIDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...SK/CQD
AVIATION...JBM/CQD
MARINE...JBM/CQD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1244 AM EST WED NOV 23 2011
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE EXPECTED AHEAD OF A STRONG COLD FRONT
LATE TONIGHT INTO WEDNESDAY MORNING. HIGH PRESSURE WILL BUILD IN FOR
THANKSGIVING INTO THE WEEKEND. COOL TEMPERATURES WILL BEGIN TO
MODERATE EARLY NEXT WEEK. ANOTHER STORM SYSTEM WILL AFFECT THE AREA
LATE SUNDAY BRINGING ANOTHER CHANCE OF RAIN WITH BELOW NORMAL
TEMPERATURES EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 11 PM TUESDAY...NO SIGNIFICANT UPDATES HAVE BEEN MADE TO THE
FORECAST THIS EVENING. THE SQUALL LINE IS PROGRESSING EAST IN CLOSE
AGREEMENT WITH THE 23Z/00Z HRRR...PERHAPS A LITTLE FASTER THAN SHOWN
ON THE 01Z HRRR. THROUGH DAYBREAK POPS RANGE FROM NEAR 100 PERCENT
WEST OF I-95 TO AROUND 40 PERCENT ON THE COAST. PREVIOUS DISCUSSION
FROM 9 PM FOLLOWS...
WE ARE CLOSELY WATCHING RADAR LOOPS OF THE SQUALL LINE ACROSS
NORTHERN GEORGIA AS IT CONTINUES SLIDING EAST TOWARD THE CAROLINAS.
SURFACE-BASED PARCELS ARE BECOMING CONVECTIVELY CAPPED AS SURFACE
TEMPERATURES FALL IN THE 60S OR NEAR 70 DEGREES...BUT FORECAST
SOUNDINGS OFF THE GFS AND NAM SHOW CAPE 600-900 J/KG AND ONLY SMALL
INHIBITION WHEN PARCELS AROUND 950 MB ARE LIFTED.
THE LAST SEVERAL RUNS OF THE HRRR ARE HELPING US PIN DOWN THE TIMING
OF THIS FEATURE AS IT PUSHES TOWARD THE COAST LATE TONIGHT. THE MAIN
LINE OF STORMS SHOULD REACH THE FLORENCE AND DARLINGTON VICINITY
AROUND 09Z/4 AM EST...THE SOUTH CAROLINA COAST FROM 11-12Z/6-7 AM
EST...AND THE NORTH CAROLINA COAST BETWEEN 12-13Z/7-8 AM EST. OF
CONCERN IS ALSO A SMALL AREA OF CONVECTION NOTED ALONG THE GEORGIA
COAST THIS EVENING. THE LAST SEVERAL HRRR RUNS LATCH ONTO THIS AND
DEVELOP IT INTO A LARGER CONVECTIVE CLUSTER THAT RIDES UP THE SC AND
NC COASTAL STRIP BETWEEN MIDNIGHT AND 4 AM. GIVEN THE MEAGER
APPEARANCE ON RADAR WE ARE NOT JUMPING ON THIS SOLUTION YET...AND
PREFER TO HOLD THE HIGHEST POPS UNTIL THE MAIN AREA OF STORMS ARRIVE
TOWARD MORNING.
IN TERMS OF SEVERE WEATHER POTENTIAL WE CAN CONTRAST THIS SITUATION
TO THE WEATHER SYSTEM LAST WEEK THAT PRODUCED TORNADOES ACROSS THE
PIEDMONT REGION AND WIND DAMAGE ACROSS THE COASTAL PLAIN. LAST
WEEK`S SYSTEM HAD A VERY FAVORABLY POSITIONED UPPER JET WHICH
PROVIDED EFFICIENT VENTILATION FOR STORMS AND AIDED SYNOPTIC LIFT.
LAPSE RATES FROM 800 THROUGH 300 MB WERE ALSO QUITE STEEP WHICH
HELPED ACCELERATE PARCELS AND PRODUCED VERY DEEP CONVECTION FOR THE
SEASON. NEITHER OF THESE TWO FACTORS ARE PRESENT TONIGHT OR IN THE
MORNING WHICH LEADS US TO BELIEVE SEVERE WEATHER POTENTIAL IS LESS.
THE ONLY FACTOR THAT CONCERNS US ABOUT POTENTIAL SEVERE WEATHER IS
VERY STRONG WIND FIELDS...50 KNOTS AS LOW AS 2300 FT AGL...WHICH
COULD BE TRANSPORTED DOWN TO THE GROUND IN CONVECTIVE DOWNDRAFTS.
LOWS TONIGHT ARE PROBABLY OCCURRING IN MOST AREAS AS I TYPE...MID
60S FOR MOST AREAS. INCREASING LOW-LEVEL WINDS AND CLOUD COVERAGE
SHOULD ALLOW TEMPERATURES TO RISE A COUPLE OF DEGREES BEFORE THE
STORMS ARRIVE. WEST OF I-95 LOWS MAY OCCUR LATE TONIGHT AS THE
CONVECTIVE BAND PUSHES THROUGH.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A PRE-FRONTAL TROUGH SHOULD BE MAKING ITS WAY
ACROSS THE FORECAST AREA BY/DURING WED MORNING WITH THE PASSAGE OF A
STRONG COLD FRONT LATE MORNING AND EARLY AFTERNOON. SURFACE BASED
INSTABILITY WILL BE VERY MODEST...WHICH SHOULD AID IN KEEPING 60 KT
JET FROM MIXING TO THE SURFACE WED MORNING. HIGH AND DEEP MOISTURE
CONTENT WILL BE IN PLACE AND WITH FRONTAL LIFT...WILL KEEP POPS IN
THE HIGH LIKELY TO CATEGORICAL RANGE. SHOWERS ARE EXPECTED WITH SOME
OF THE STRONGEST CONVECTION CONTAINING THUNDER AND PERHAPS SOME
GUSTY WINDS. STRONG COLD AND DRY AIR ADVECTION WILL NOT ENSUE UNTIL
AFTER FRONTAL PASSAGE. UNLIKE THE LAST STRONG COLD FRONT...TEMPS ARE
NOT EXPECTED TO FALL SIGNIFICANTLY THROUGH THE DAYLIGHT HOURS.
STRONG GUSTY SW WINDS ON WED WILL SHIFT TO NW WITH FRONTAL PASSAGE
AND THESE GUSTY WINDS WILL PERSIST INTO WED NIGHT. TEMPS ON WED...IN
THE LOWER 70S WILL BE ABOUT 10 DEG COLDER ON THU. LOWS WED NIGHT
AROUND 40 WILL BE IN THE 30S THU NIGHT WITH SOME BELOW FREEZING
TEMPS IN A FEW PLACES AS STRONG RADIATIONAL COOLING DEVELOPS DURING
THE EVE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...THE LONG TERM STARTS OUT VERY QUIET BUT MAY END
ON A RATHER TUMULTUOUS NOTE. SURFACE HIGH PRESSURE SPREAD ACROSS THE
SOUTHEAST ON FRIDAY WILL MIGRATE EASTWARD ON SATURDAY. RIDGING ALOFT
WILL FOLLOW CLOSELY IN PHASE WITH THE SURFACE ANTICYCLONE. TWO UPPER
SYSTEMS PHASE FRIDAY NIGHT INTO SATURDAY JUST EAST OF THE ROCKIES
AND THE RESULTING FULL LATITUDE TROUGH WILL SHARPEN FURTHER ON
SUNDAY...SLOWING ITS EASTWARD PROGRESSION. FRIDAY THROUGH SUNDAY
WILL THUS BRING ABOVE CLIMO TEMPS THAT WILL SHOW A SLIGHT WARMING
TREND EACH DAY. THE DOWNSTREAM RIDGING AT THE SURFACE AND ALOFT WILL
HOLD ITS GROUND ACROSS THE CAROLINAS AND MOISTURE FLUX AHEAD OF THIS
SYSTEM WILL BE DELAYED UNTIL A FEW HOURS PRIOR TO ITS ARRIVAL
ALTHOUGH IT WILL BE VIGOROUS ONCE IT ARRIVES. CURRENTLY THIS APPEARS
TO BE EITHER SUNDAY EVENING OR OVERNIGHT...WITH SOME VARIOUS SENSES
OF TIMING OFFERED BY DIFFERENT MODELS. GIVEN THE STRENGTH OF THE
AFOREMENTIONED DOWNSTREAM UPPER RIDGE THE SLOWER TIMING SEEMS TO
HAVE SOME MERIT. THE HIGH AMPLITUDE OF THE FLOW ALOFT WILL
DIMINISH THE LIKELIHOOD OF PRECIP ASSOCIATED WITH A PRE-FRONTAL SFC
TROUGH AS SEEN WITH RECENT FROPAS ON ACCOUNT OF THE HIGH COMPONENT
OF MERIDIONAL FLOW. A SHARPLY COLDER AIRMASS WILL MOVE IN ON
MONDAY...WHICH HAS MADE THAT AFTERNOONS FORECAST HIGH TEMPERATURE
DIFFICULT SINCE THERE MAY VERY WELL BE FALLING TEMPERATURES THAT
AFTERNOON. TUESDAY WILL ALSO BE RATHER COOL WITH SOME SELF-
DESTRUCT SUNSHINE AND INSTABILITY SHOWERS POSSIBLE DUE TO VERY
COLD AIR ALOFT.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...CURRENT FORECAST IS BASICALLY ON TRACK. HAVE MOVED UP
THE ONSET OF PRECIP AN HOUR OR SO TO ACCOMMODATE CURRENT TRENDS...AS
WELL AS THE LATEST HRRR MODEL RUNS. FAIRLY POTENT PRE-FRONTAL TROF
WILL PASS THROUGH ACROSS THE FA TOWARD DAYBREAK...WITH THE ACTUAL
COLD FRONTAL PASSAGE SLATED FOR MIDDAY TODAY. PRE-FRONTAL TSRA/SHRA
WILL RESULT IN A BRIEF IFR/LIFR CEILING/VSBY...WITH POSSIBLE WIND
GUSTS UP TO 25 TO 40 KT FROM THE CONVECTION. WINDS TO VEER FROM S TO
SW-W AFTER THE TROFS PASSAGE...AND INCREASE TO 15KT WITH GUSTS UP TO
25 KT. LOOK FOR CONVECTION TO EXIT THE COAST BY 14Z. THE COLD
FRONTAL PASSAGE FROM WEST TO EAST...IS SLATED FOR MIDDAY TODAY.
COULD SEE A STRAY SHRA ALONG THE ACTUAL FRONT WITH POSSIBLE IFR
CEILINGS PRIOR TO ITS PASSAGE. FOR POST FRONTAL CONDITIONS...EXPECT
A QUICK IMPROVEMENT TO VFR CEILINGS...WITH SKC COMMON BY SUNSET.
GUSTY W TO NW WINDS WITH 10-20KT SUSTAINED...WITH GUSTS UP TO 25 TO
30 KT DURING THE AFTERNOON. WINDS TO DROP TO 10-15 KT AFTER SUNSET
WITH GUSTS STILL UP TO 20 KT DURING THE EVENING.
EXTENDED OUTLOOK...EXPECT VFR THROUGH PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 11 PM TUESDAY...COOL STABLE AIR OVER THE NEARSHORE WATERS IS
NOT ALLOWING WIND SPEEDS TO INCREASE AS THE PRESSURE GRADIENT
BECOMES TIGHTER OUT AHEAD OF THE COLD FRONT. WIND SPEEDS OUT AT THE
FRYING PAN SHOALS BUOY HAVE INCREASED TO AROUND 20 KNOTS...WHILE
NEARSHORE SPEEDS ARE BARELY 10 KNOTS. THE DIFFERENCE IS DUE TO AN
8-DEGREE AIR AND WATER TEMPERATURE DIFFERENCE AND WHAT THAT IS DOING
TO THE STABILITY OF THE LOWEST FEW HUNDRED FEET OF THE ATMOSPHERE.
BESIDES THESE EDITS TO WIND SPEED FORECASTS THROUGH DAYBREAK...NO
OTHER SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST THIS
EVENING.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL PERSIST
THROUGH THU. SW WINDS WILL SHIFT TO NW IN THE WAKE OF A STRONG
COLD FRONT WED AFTERNOON AND THESE WINDS WILL STRENGTHEN WED NIGHT
AS THEY VEER TO N. N WINDS WILL GRADUALLY DIMINISH DURING
THU...BECOMING NE THU NIGHT. SEAS SHOULD PEAK ON WED AND THEN
STABILIZE OR SUBSIDE ON STRONG NW WINDS WED NIGHT AND THU...
ESPECIALLY ACROSS THE NEAR SHORE WATERS DUE TO THE STRONG OFFSHORE
FLOW. IN FACT...WE WILL BE NEARING LOW WATER ADVISORY CRITERIA
AROUND THE TIME OF LOW TIDE LATE WED NIGHT.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...HIGH PRESSURE WILL BE SETTLED ACROSS THE
SOUTHEASTERN U.S. ON FRIDAY. HOWEVER A MODERATELY STRONG PRESSURE
GRADIENT WILL STILL BE FOUND ON THE EASTERN PERIPHERY OF THIS
AIRMASS ESPECIALLY EARLY ON. THIS MAY GIVE RISE TO CAUTIONARY
HEADLINES OUT NEAR FRYING PAN SHOALS TO START THE PERIOD BUT A
DOWNWARD TREND WILL BE OBSERVED IN BOTH WINDS AND SEAS AS THE DAY
WEARS ON AND THE HIGH PROGRESSES EAST. THE REMAINDER OF THE
WEEKEND WILL SEE HIGH PRESSURE ACROSS THE COASTAL WATERS KEEPING
WINDS LIGHT AND SEAS DIMINUTIVE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM WEDNESDAY TO 6 PM EST
THURSDAY FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...RJD
LONG TERM...MBB
AVIATION...DCH/HDL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
948 PM EST THU NOV 24 2011
.SYNOPSIS...
HIGH PRESSURE WITH DRY WEATHER CONTINUES SATURDAY. MORE RAIN SUNDAY
WITH THE NEXT LOW PRESSURE SYSTEM. TURNING COLDER WITH RAIN AND SNOW
SHOWERS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
UPDATE...
HAVE MADE SOME SIGNIFICANT ADJUSTMENTS TO THE OVERNIGHT LOW
TEMPERATURES WITH THIS UPDATE. COOL SPOTS/VALLEYS HAVE DROPPED
QUICKLY...WHILE ELEVATED SITES IN THE WARMER BOUNDARY LAYER AIR
STILL REMAIN IN THE 40S IN SOME LOCATIONS. THIS INCLUDES SNOWSHOE.
LOCAL COOP MOS GUIDANCE IS BULLISH ON SOME OF THE LOWS GETTING
DOWN INTO THE MID 20S TONIGHT FOR PLACES LIKE NORTHEAST KENTUCKY
AND NORTHEAST OF PKB. SAME GUIDANCE ALSO SUGGESTS TEENS IN THE
GREENBRIER VALLEY OF POCAHONTAS COUNTY.
STILL ON BOARD WITH THE RUC AND THE LOW LEVEL STRATUS DECK
REDEVELOPING NEAR THE OHIO RIVER VALLEY INTO SOUTHEAST OHIO. EXTENT
OF THE OVERALL CLEARING CURRENTLY TAKING PLACE IS DECREASING
CONFIDENCE AT THE TIME OF THIS ISSUANCE.
PREVIOUS DISCUSSION...
NO SMELL OF TURKEY HERE. EVEN UNDER THE HIGH PRESSURE...THERE ARE
ISSUES. STRATUS UNDER THE TEMPERATURE INVERSION CONTINUES TO ERODE
FROM THE SOUTH. BY 22Z SUNSET...FIGURING THE STRATUS ONLY LEFT IN
OHIO.
WILL TRY TO REFORM...OR ADVECT...SOME OF THAT STRATUS 06Z TO 12Z
FRIDAY BACK IN SOUTHEAST OHIO AND MAYBE REACHING INTO NORTHWESTERN
WEST VIRGINIA INCLUDING THE PKB VCNTY. WITH WARMER BOUNDARY LAYER
TEMPERATURES...DO NOT THINK THE STRATUS WILL REFORM IN SOUTHERN WEST
VIRGINIA. SO CAN NOT RULE OUT SOME LOCAL VALLEY FOG IN THE DEEPER
VALLEYS THERE...UNDER THE CLEAR SKY 06Z TO 13Z.
HAVE NOT REEVALUATED TEMPERATURES...BUT DO NOT FORESEE ANY MAJOR
CHANGES THROUGH FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE RIDGE ALOFT...AND A SURFACE HIGH PRESSURE WILL
PROVIDE CLEAR SKIES...AND DRY WEATHER CONDITIONS INTO THE DAY
SATURDAY.
THIS SCENARIO MEANS WARM AFTERNOON DUE TO HEATING...AND CHILLY
NIGHTS DUE TO RADIATIONAL COOLING AND STRONG SUBSIDENCE.
A LARGE DIURNAL RANGE IN TEMPERATURES WITH NEAR NORMAL LOWS BUT
ABOVE NORMAL HIGHS INTO THE 60S IS EXPECTED.
A COLD FRONT CROSS THE AREA EARLY SUNDAY. MODEL CONSENSUS SUGGEST
TEMPERATURES AT H850 REACHING MINUS 3 BY 12Z SUNDAY.
THEREFORE...EXPECT LIQUID PRECIPITATION WITH THE COLD FRONT ON
SUNDAY...PERHAPS MIXING WITH SNOW LATE OVER THE NORTHEAST
MOUNTAINS.
PEOPLE COMING BACK FROM THANKSGIVING WEEKEND COULD ENCOUNTER WET
ROADS ON SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
LOW CONFIDENCE CONTINUES IN THE LONG TERM PERIOD AS MODELS CONTINUE
TO DIFFER WITH THE HANDLING OF NEXT STORM SYSTEM...PROGGED TO MOVE
INTO THE REGION ON SUNDAY. 12Z RUN OF THE GFS INDICATES BULK OF
PRECIPITATION AND COLD FRONTAL BOUNDARY WILL BE ON THE WAY OUT OF
THE CWA BY THE START OF THE PERIOD...WITH COLDER AIR FILTERING IN
OVERNIGHT AS UPPER TROUGH CONTINUES TO PUSH EAST...WITH CAA PATTERN
FOR MONDAY. GFS THEN INDICATES A CLOSED LOW FORMING OVER THE
CAROLINAS...BEFORE TREKKING OFF TO THE EAST OVER THE ATLANTIC AS
SHORTWAVE RIDGING BUILDS INTO THE REGION. ECMWF CONTINUES TO
INDICATE A CLOSED LOW FORMING NEAR GULF STATES...BEFORE TREKKING
NORTHEAST TOWARDS THE REGION. THIS SCENARIO WOULD CREATE A PROLONGED
PERIOD OF WET WEATHER...AND WARMER TEMPERATURES THAT WOULD ALLOW FOR
THE BULK OF PRECIPITATION TO BE IN THE FORM OF RAIN. FOLLOWED HPC
THINKING...WHICH IS MORE PROGRESSIVE...AND FOLLOWS GFS MEAN SOLUN.
VERY TRICKY FORECAST IN TERMS OF PRECIPITATION TYPE ON SUNDAY
NIGHT/EARLY MONDAY. TEMPERATURES ARE EXPECTED TO BE COLD ENOUGH FOR
MUCH OF THE PRECIPITATION TO CHANGE OVER TO ALL SNOW...OR A
RAIN/SNOW MIX SUNDAY NIGHT...HOWEVER...DRIER AIR WILL ALSO BE
WORKING ITS WAY INTO UPPER AND MID LEVELS. AS A RESULT...REALLY NO
MOISTURE EXPECTED IN THE CRYSTAL GROWTH ZONE...AND IT IS
POSSIBLE...SOME OF THE PRECIPITATION MAY BE IN THE FORM OF A
FREEZING DRIZZLE...PARTICULARLY OVER THE LOWLAND COUNTIES. WITH THE
WARM GROUND TEMPERATURES HOWEVER...THIS WILL LIKELY MITIGATE ANY
MAJOR ISSUES TRAVEL WISE. FOR NOW...TO KEEP IN LINE WITH NEIGHBORS AND
DUE TO THE FACT THAT THE EVENT IS SEVERAL DAYS AWAY...KEPT
PRECIPITATION MAINLY AS SNOW OR A RAIN/SNOW MIX IN THE GRIDS. BEST
PLACE FOR ANY SNOWFALL ACCUMULATIONS SUNDAY NIGHT/MONDAY WILL BE
OVER THE NORTHERN MOUNTAIN ZONES...WHERE MODELS INDICATE AROUND 4
INCHES OR SO POSSIBLE. KEPT AMOUNTS GENERALLY LESS THAN THAT FOR
NOW...BUT WILL CONTINUE TO MONITOR FOR FUTURE FORECASTS.
PATTERN CONTINUES TO REMAIN PROGRESSIVE FOR THE REMAINDER OF THE
EXTENDED PERIOD WITH LOW FORECAST CONFIDENCE.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
LOW STRATUS HAS DEPARTED PKB...BUT FEEL A RETURN IS POSSIBLE AFTER
06Z. USING THE RUC AND ITS LOW LEVEL MOISTURE PROGS WHICH HAS THE
BEST HANDLE ON IT OVERALL. WILL HOVER AROUND THE 1KFT LEVEL...AND
GO CONSERVATIVE AND USE MVFR IN THE PKB TAF. ELSEWHERE...IFR
VISIBILITIES IN THE VALLEYS AWAY FROM THE LOW CLOUDS...MORE
ADJACENT TO THE MOUNTAINS POSSIBLE...ESPECIALLY AT EKN.
AGAIN...PREDOMINANT VISIBILITY WILL BE MVFR IN THESE AREAS AS
GUIDANCE CONTINUES TO STRUGGLE WITH THE FOG POTENTIAL. VFR WITH
CEILINGS AND VISIBILITIES UNLIMITED FRIDAY AS LOW LEVEL CLOUDS
DISSOLVE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: THE EXTENT OF THE OVERNIGHT STRATUS AND HOW FAR
EAST DEVELOPS INTO NORTHWESTERN WEST VIRGINIA MAY VARY. ALSO
TIMING ANY VALLEY FOG FORMATION MAY VARY IN THE DEEP VALLEYS IN WEST
VIRGINIA.
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 FRI 11/25/11
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 M M M M M M M M
HTS CONSISTENCY H H H H H H M M H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H L L L L L L
PKB CONSISTENCY H L M M L L L L M M M M
CKB CONSISTENCY M M L L M M H H H H H H
AFTER 00Z SATURDAY...
IFR POSSIBLE IN RAIN AND SNOW SUNDAY INTO MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/ARJ/SL
NEAR TERM...KTB/26
SHORT TERM...ARJ
LONG TERM...SL
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
632 PM EST THU NOV 24 2011
.SYNOPSIS...
HIGH PRESSURE WITH DRY WEATHER CONTINUES SATURDAY. MORE RAIN SUNDAY
WITH THE NEXT LOW PRESSURE SYSTEM. TURNING COLDER WITH RAIN AND SNOW
SHOWERS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
UPDATE...
LOW LEVEL STRATUS CONTINUES TO BE A PROBLEM...AND COULD ADVECT
TOWARDS THE OHIO RIVER AGAIN TONIGHT. CURRENTLY...IT IS RETREATING
INTO CENTRAL OHIO...AND ALLOWED PKB TO COME INTO A CLEAR SKY. RUC
IS THE MODEL OF CHOICE REGARDING THIS...AS IT WAS LAST NIGHT...AND
HAVE TAKEN STOCK IN IT FOR THIS UPDATE. STILL...THE EASTWARD EXTEND
OF THE LOW STRATUS WILL BE PROBLEMATIC. DO NOT SEE IT REACHING
HTS-CRW-CKB LINE...BUT FEEL PKB COULD BE BACK INTO IT IN A FEW
HOURS.
OTHERWISE...NO MAJOR CHANGES. TEMPERATURES LOOK GOOD...AND NO
PRECIPITATION EXPECTED.
PREVIOUS DISCUSSION...
NO SMELL OF TURKEY HERE. EVEN UNDER THE HIGH PRESSURE...THERE ARE
ISSUES. STRATUS UNDER THE TEMPERATURE INVERSION CONTINUES TO ERODE
FROM THE SOUTH. BY 22Z SUNSET...FIGURING THE STRATUS ONLY LEFT IN
OHIO.
WILL TRY TO REFORM...OR ADVECT...SOME OF THAT STRATUS 06Z TO 12Z
FRIDAY BACK IN SOUTHEAST OHIO AND MAYBE REACHING INTO NORTHWESTERN
WEST VIRGINIA INCLUDING THE PKB VCNTY. WITH WARMER BOUNDARY LAYER
TEMPERATURES...DO NOT THINK THE STRATUS WILL REFORM IN SOUTHERN WEST
VIRGINIA. SO CAN NOT RULE OUT SOME LOCAL VALLEY FOG IN THE DEEPER
VALLEYS THERE...UNDER THE CLEAR SKY 06Z TO 13Z.
HAVE NOT REEVALUATED TEMPERATURES...BUT DO NOT FORESEE ANY MAJOR
CHANGES THROUGH FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE RIDGE ALOFT...AND A SURFACE HIGH PRESSURE WILL
PROVIDE CLEAR SKIES...AND DRY WEATHER CONDITIONS INTO THE DAY
SATURDAY.
THIS SCENARIO MEANS WARM AFTERNOON DUE TO HEATING...AND CHILLY
NIGHTS DUE TO RADIATIONAL COOLING AND STRONG SUBSIDENCE.
A LARGE DIURNAL RANGE IN TEMPERATURES WITH NEAR NORMAL LOWS BUT
ABOVE NORMAL HIGHS INTO THE 60S IS EXPECTED.
A COLD FRONT CROSS THE AREA EARLY SUNDAY. MODEL CONSENSUS SUGGEST
TEMPERATURES AT H850 REACHING MINUS 3 BY 12Z SUNDAY.
THEREFORE...EXPECT LIQUID PRECIPITATION WITH THE COLD FRONT ON
SUNDAY...PERHAPS MIXING WITH SNOW LATE OVER THE NORTHEAST
MOUNTAINS.
PEOPLE COMING BACK FROM THANKSGIVING WEEKEND COULD ENCOUNTER WET
ROADS ON SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
LOW CONFIDENCE CONTINUES IN THE LONG TERM PERIOD AS MODELS CONTINUE
TO DIFFER WITH THE HANDLING OF NEXT STORM SYSTEM...PROGGED TO MOVE
INTO THE REGION ON SUNDAY. 12Z RUN OF THE GFS INDICATES BULK OF
PRECIPITATION AND COLD FRONTAL BOUNDARY WILL BE ON THE WAY OUT OF
THE CWA BY THE START OF THE PERIOD...WITH COLDER AIR FILTERING IN
OVERNIGHT AS UPPER TROUGH CONTINUES TO PUSH EAST...WITH CAA PATTERN
FOR MONDAY. GFS THEN INDICATES A CLOSED LOW FORMING OVER THE
CAROLINAS...BEFORE TREKKING OFF TO THE EAST OVER THE ATLANTIC AS
SHORTWAVE RIDGING BUILDS INTO THE REGION. ECMWF CONTINUES TO
INDICATE A CLOSED LOW FORMING NEAR GULF STATES...BEFORE TREKKING
NORTHEAST TOWARDS THE REGION. THIS SCENARIO WOULD CREATE A PROLONGED
PERIOD OF WET WEATHER...AND WARMER TEMPERATURES THAT WOULD ALLOW FOR
THE BULK OF PRECIPITATION TO BE IN THE FORM OF RAIN. FOLLOWED HPC
THINKING...WHICH IS MORE PROGRESSIVE...AND FOLLOWS GFS MEAN SOLUN.
VERY TRICKY FORECAST IN TERMS OF PRECIPITATION TYPE ON SUNDAY
NIGHT/EARLY MONDAY. TEMPERATURES ARE EXPECTED TO BE COLD ENOUGH FOR
MUCH OF THE PRECIPITATION TO CHANGE OVER TO ALL SNOW...OR A
RAIN/SNOW MIX SUNDAY NIGHT...HOWEVER...DRIER AIR WILL ALSO BE
WORKING ITS WAY INTO UPPER AND MID LEVELS. AS A RESULT...REALLY NO
MOISTURE EXPECTED IN THE CRYSTAL GROWTH ZONE...AND IT IS
POSSIBLE...SOME OF THE PRECIPITATION MAY BE IN THE FORM OF A
FREEZING DRIZZLE...PARTICULARLY OVER THE LOWLAND COUNTIES. WITH THE
WARM GROUND TEMPERATURES HOWEVER...THIS WILL LIKELY MITIGATE ANY
MAJOR ISSUES TRAVEL WISE. FOR NOW...TO KEEP IN LINE WITH NEIGHBORS AND
DUE TO THE FACT THAT THE EVENT IS SEVERAL DAYS AWAY...KEPT
PRECIPITATION MAINLY AS SNOW OR A RAIN/SNOW MIX IN THE GRIDS. BEST
PLACE FOR ANY SNOWFALL ACCUMULATIONS SUNDAY NIGHT/MONDAY WILL BE
OVER THE NORTHERN MOUNTAIN ZONES...WHERE MODELS INDICATE AROUND 4
INCHES OR SO POSSIBLE. KEPT AMOUNTS GENERALLY LESS THAN THAT FOR
NOW...BUT WILL CONTINUE TO MONITOR FOR FUTURE FORECASTS.
PATTERN CONTINUES TO REMAIN PROGRESSIVE FOR THE REMAINDER OF THE
EXTENDED PERIOD WITH LOW FORECAST CONFIDENCE.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
LOW STRATUS HAS DEPARTED PKB...BUT FEEL A RETURN IS POSSIBLE AFTER
06Z. USING THE RUC AND ITS LOW LEVEL MOISTURE PROGS WHICH HAS THE
BEST HANDLE ON IT OVERALL. WILL HOVER AROUND THE 1KFT LEVEL...AND
GO CONSERVATIVE AND USE MVFR IN THE PKB TAF. ELSEWHERE...IFR
VISIBILITIES IN THE VALLEYS AWAY FROM THE LOW CLOUDS...MORE
ADJACENT TO THE MOUNTAINS POSSIBLE...ESPECIALLY AT EKN.
AGAIN...PREDOMINANT VISIBILITY WILL BE MVFR IN THESE AREAS AS
GUIDANCE CONTINUES TO STRUGGLE WITH THE FOG POTENTIAL. VFR WITH
CEILINGS AND VISIBILITIES UNLIMITED FRIDAY AS LOW LEVEL CLOUDS
DISSOLVE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: THE EXTENT OF THE OVERNIGHT STRATUS AND HOW FAR
EAST DEVELOPS INTO NORTHWESTERN WEST VIRGINIA MAY VARY. ALSO
TIMING ANY VALLEY FOG FORMATION MAY VARY IN THE DEEP VALLEYS IN WEST
VIRGINIA.
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 FRI
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06
CRW CONSISTENCY H H H H M M M H M M M M
HTS CONSISTENCY H H H H H H M H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H L L L L
PKB CONSISTENCY M M L L M M L M M M M M
CKB CONSISTENCY M M L L L L M M H H H H
AFTER 00Z SATURDAY...
IFR POSSIBLE IN RAIN AND SNOW SUNDAY INTO MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/ARJ/SL
NEAR TERM...KTB/26
SHORT TERM...ARJ
LONG TERM...SL
AVIATION...26
AREA FORECAST DISCUSSION
NWS NORMAN OK
816 PM CST THU NOV 24 2011
.UPDATE...
STRATUS HAS SPREAD NORTH/NORTHWEST QUICKLY THIS EVENING AND HRRR
SUGGESTS THAT THIS TREND WILL CONTINUE THROUGH THE NIGHT WITH
BROKEN TO OVERCAST SKIES LIKELY ENVELOPING THE EASTERN TWO-THIRDS
OR SO OF THE FORECAST AREA BY SUNRISE. HAVE MADE A MAJOR OVERHAUL
TO THE SKY GRIDS. ALTHOUGH THERE MAY BE SOME LOCATIONS WITH
RESTRICTED VISIBILITY... EXPECT WINDS TO REMAIN STRONG ENOUGH THAT
DO NOT EXPECT VERY MUCH DENSE FOG... ALTHOUGH THE HRRR DISAGREES
WITH THIS AND WILL CONTINUE TO WATCH TRENDS OVERNIGHT. HAVE ALSO
MADE BIG CHANGES TO THE HOURLY TEMPERATURE GRIDS DUE TO THE QUICK
DROP OF TEMPERATURES THIS EVENING AND USED THE RUC AS THE PRIMARY
SOURCE FOR THE TEMPERATURES. THIS ALSO REQUIRED SOME ADJUSTMENT TO
THE OVERNIGHT MINIMUM TEMPERATURE FORECAST ALTHOUGH IT APPEARS
THAT THESE CHANGES ARE MINOR IN MOST LOCATIONS.
&&
.PREV DISCUSSION... /ISSUED 600 PM CST THU NOV 24 2011/
AVIATION...
/00Z TAFS/
MAIN AVIATION ISSUE WILL OCCUR TONIGHT IN REGARDS TO THE
EVOLUTION AND MOVEMENT OF THE STRATUS DECK CURRENTLY IN SE OK.
BELIEVE IT WILL MOVE INTO PORTIONS OF CENTRAL AND SW OK... AND
WESTERN N-TX LATER TONIGHT... AND GIVEN MOST RECENT SATELLITE
TRENDS... IT MAY SPREAD FASTER THAN PREVIOUSLY EXPECTED. ALSO
MENTIONED LIKELIHOOD OF LLWS LATER TONIGHT IN SEVERAL LOCATIONS
AS THE LOW LEVEL JET STRENGTHENS. LOW CLOUDS EXPECTED TO SCATTER
OUT THURSDAY MORNING. MEANWHILE... A FEW SHOWERS MAY BEGIN TO
SPREAD INTO NW OK BY LATE IN THE DAY.
PREV DISCUSSION... /ISSUED 156 PM CST THU NOV 24 2011/
DISCUSSION...
CLOUDS CONTINUE TO ERODE IN SE PORTIONS OF THE FA THIS AFTERNOON.
HOWEVER... THEY ARE SLOW TO DO SO WHICH MEANS CLOUDS COULD LINGER
INTO THE EVENING. OTHERWISE... QUIET NIGHT TONIGHT WITH ONLY SOME
HIGH CLOUDS STREAMING INTO THE REGION AS UPPER TROUGH MOVING ACROSS
THE SW U.S. APPROACHES THE AREA. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE FRIDAY AS THE STORM SYSTEM APPROACHES WITH CHANCES
EXPANDING EAST AND RAIN BECOMING MORE WIDESPREAD FRIDAY NIGHT. HEAVY
RAIN IS NOT EXPECTED WITH THIS SYSTEM. THE UPPER SYSTEM WILL EXIT
THE REGION SATURDAY WITH RAIN CHANCES ENDING FOR THE FA BY AROUND
THE MIDDLE OF THE DAY SATURDAY. A COLD FRONT WILL ALSO MOVE ACROSS
THE REGION FRIDAY NIGHT INTO SATURDAY. STRONG NORTH WINDS ARE
EXPECTED BEHIND THE FRONT SATURDAY MAKING CONDITIONS FEEL MUCH
COOLER THAN THEY ARE.
TEMPERATURES WILL WARM SUNDAY INTO MONDAY BEFORE ANOTHER COLD FRONT
MOVES ACROSS THE REGION LATE MONDAY INTO TUESDAY. THIS FRONTAL
PASSAGE IS EXPECTED TO BE DRY BUT WILL BRING A COOLER AIRMASS TO THE
REGION. MODELS SHOW ANOTHER UPPER SYSTEM AND COLD FRONT AFFECTING
THE REGION TOWARDS THE END OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 46 64 45 51 / 0 20 70 10
HOBART OK 50 64 40 50 / 0 30 50 10
WICHITA FALLS TX 51 65 46 55 / 0 20 70 10
GAGE OK 47 65 36 45 / 0 40 40 0
PONCA CITY OK 46 65 43 49 / 0 20 70 10
DURANT OK 47 65 51 56 / 0 10 70 40
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
956 AM EST WED NOV 23 2011
.DISCUSSION...
THE UPPER TROUGH AXIS IS SWINGING THROUGH THE AREA THIS MORNING.
UPSTREAM SOUNDINGS INDICATE THAT DRIER AIR ALOFT WILL CONTINUE TO
ADVECT IN THROUGH THE AFTERNOON BEHIND THE TROUGH. 12Z OHX SOUNDING
SHOWS MOISTURE CONFINED BELOW 850 MB...AND MOISTURE DEPTH WILL ONLY
DECREASE THROUGH THE DAY. AS A RESULT...WILL REMOVE THE SLIGHT
CHANCE POP IN NORTHERN AREAS AND THE MOUNTAINS. CLOUDS WILL
EVENTUALLY THIN OUT AS BOTH THE RUC AND NAM SHOW CLEARING LATE IN
THE AFTERNOON...BUT EXPECT THIS TO OCCUR A BIT MORE SLOWLY THAN THE
MODELS SUGGEST. THUS WILL LOWER TEMPERATURES SLIGHTLY IN ALL
LOCATIONS.
THE NEED FOR A WIND ADVISORY WAS CONSIDERED IN SW VA AND THE TN
MOUNTAINS...HOWEVER THERE HAVE BEEN NO OBSERVATIONS IN THE AREA
CLOSE TO ADVISORY CRITERIA...AND MODELS INDICATE DECREASING WINDS
THROUGH THE DAY AS THE SURFACE LOW MOVES FARTHER OFF THE NEW
ENGLAND COAST. NO WIND ADVISORY WILL BE NEEDED.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1132 PM CST TUE NOV 22 2011
.AVIATION...
CONCERNS...IFR TO MVFR FOG LATE TONIGHT.
T-TD SPREADS ARE CLOSING AND WINDS ARE LIGHT...THUS FEEL MVFR FOG
WILL FORM AFTER 08Z AND BURN OFF AROUND 15Z WEDNESDAY MORNING.
THERE IS A POTENTIAL FOR 1/2-2SM AND VV001 OR OVC002 TO FORM AS
WELL AND DECIDED TO USE TEMPO 11-14Z TO INDICATE THIS. CONFIDENCE
FOR THIS EVENT IS MODERATE TO HIGH...BUT NOT 100 PERCENT.
OTHERWISE...LIGHT NORTHWEST WINDS WILL VEER SOUTHEASTERLY
WEDNESDAY AFTERNOON/EVENING AS THE SURFACE HIGH MOVES EAST OF THE
TAF SITES. SPEEDS WILL REMAIN 6KT OR LESS. 75
&&
.UPDATE...
SCATTERED TO BROKEN STRATUS THAT HAS LINGERED SINCE THIS AFTERNOON
IS FINALLY SHOWING SIGNS OF ERODING NOW THAT A DRIER AIRMASS AND
LOWER DEW POINTS OVER OKLAHOMA ARE FILTERING ACROSS THE RED RIVER
VALLEY. PER LOOK AT THE RUC/NAM/NAMM/AND SREF FAMILIES ON BUFKIT AND
AT THE CROSS-OVER TEMPERATURE METHOD...INDICATIONS ARE THAT CURRENT
TRENDS AND LOW TEMPERATURES FALLING TO...OR JUST BELOW AFTERNOON DEW
POINT TEMPERATURES WILL RESULT IN SOME FOG DEVELOPMENT OVERNIGHT AND
EARLY WEDNESDAY MORNING. FOG FORMATION SHOULD BECOME MORE EXPANSIVE
BY DAYBREAK AND THROUGH A BULK OF THE MORNING WEDNESDAY.
A MAJORITY OF NORTH TEXAS SAW RAINFALL THE PAST 24 HOURS...WITH A
FEW STRIPES OF HEAVIER RAINS BOTH ALONG AND JUST SOUTH OF THE RED
RIVER VALLEY AND ACROSS AREAS SOUTHEAST OF THE DALLAS-FORT WORTH
METROPLEX. THESE AREAS MAY SEE THE HIGHEST RISK OF FOG DEVELOPMENT
OVERNIGHT DUE TO HIGHER SATURATION.
FOR NOW...WE WILL MAINTAIN PATCHY FOG WORDING THROUGH 3 AM FOR ALL
OF NORTH TEXAS...THEN GO TO MORE AREAS OF FOG WITH PATCHY DENSE
FOG FROM THE PREDAWN HOURS THROUGH LATE MORNING WEDNESDAY...BEING
THAT IT IS GETTING INTO THE CRUX OF THE COOL SEASON. THE FORECAST
WILL BE A COMPROMISE BETWEEN THE MORE PESSIMISTIC RUC MODEL...AND
THE MORE OPTIMISTIC NAM/NAMM/SREF MODELS WHICH ONLY HAVE FOG
POTENTIAL THROUGH MID MORNING.
IT IS POSSIBLE A DENSE FOG ADVISORY MAY BE ISSUED EARLY WEDNESDAY
MORNING FOR PARTS OF NORTH TEXAS...BUT COVERAGE OF ANY DENSE FOG
IS UNCERTAIN AT THIS TIME AND WILL NOT ISSUE ANY ADVISORIES ON
THIS UPDATE.
05/
&&
.PREV DISCUSSION... /ISSUED 317 PM CST TUE NOV 22 2011/
ISENTROPIC DOWNGLIDE IS SLOWLY WORKING TO ERODE LOW LEVEL CLOUD
COVER AND THIS PROCESS SHOULD CONTINUE THROUGH THE EVENING HOURS.
CLOUDS SHOULD BE GONE FROM THE CWA BY MIDNIGHT...AND WITH
DECREASING WINDS...ABUNDANT SHALLOW MOISTURE FROM RECENT
RAIN...AND VERY DRY AIR ALOFT...CONDITIONS LOOK FAVORABLE FOR
PATCHY FOG. THE ONLY THING HOLDING BACK FOG DEVELOPMENT MAY BE
THAT THE WINDS ARE JUST A BIT TOO STRONG...SO FOG IN VALLEYS IS
PROBABLY MORE LIKELY. ASIDE FROM ANY MORNING FOG...EXPECT A VERY
NICE WEDNESDAY WITH PLEASANT TEMPERATURES...LIGHT WINDS AND LOTS
OF SUNSHINE. RADIATIONAL COOLING LOOKS IDEAL ON WEDNESDAY NIGHT
AND TEMPS SHOULD MEET DEWPOINTS AGAIN. HOWEVER LOW LEVEL MOISTURE
LOOKS A BIT TOO SHALLOW FOR FOG WEDNESDAY NIGHT. THANKSGIVING DAY
WILL ALSO BE PLEASANT...BUT SOUTH WINDS WILL INCREASE TO 10 TO 15
MPH IN THE AFTERNOON AS THE NEXT UPPER LEVEL TROUGH APPROACHES
FROM THE WEST. THESE INCREASING SOUTH WINDS WILL BRING GULF
MOISTURE/CLOUDS RAPIDLY BACK INTO THE AREA ON FRIDAY.
MODELS HAVE SLOWED DOWN THE PASSAGE OF THIS SYSTEM A BIT...BUT AM
CONCERNED THEY ARE STILL TOO FAST. THE ENERGY AT THE BASE OF THIS
TROUGH MAY CLOSE OFF AND TEMPORARILY STALL OFF THE BAJA COAST ON
THURSDAY...AS THERE IS QUITE A BIT OF DISTANCE BETWEEN THIS SYSTEM
AND WHAT WOULD BE THE KICKER TROUGH IN THE CENTRAL PACIFIC. WILL
PUSH BACK THE TIMING OF THIS SYSTEM 6-12 HOURS...AND THIS SUGGESTS
RAIN CHANCES WILL HOLD OFF UNTIL AFTER SUNSET FRIDAY BUT CONTINUE
INTO SATURDAY MORNING. WITH THE SLOWER TIMING...WE SHOULD GET
BETTER THETA-E AIR INTO THE REGION...ESPECIALLY IN THE EASTERN
ZONES. LAPSE RATES ARE NOT VERY IMPRESSIVE...SO ANY SEVERE WEATHER
THREAT SHOULD BE LIMITED BY WEAK INSTABILITY.
COLD FRONT WILL BLAST THROUGH DURING THE DAY SATURDAY WITH VERY
WINDY AND COOLER CONDITIONS IN ITS WAKE. AFOREMENTIONED UPPER
TROUGH SHOULD DEEPEN AND LUMBER ACROSS THE EASTERN US EARLY NEXT
WEEK. THIS WILL ENSURE A DRY NORTHERLY FLOW THROUGH MID WEEK.
LOOKS LIKE A BRIEF WARMUP ON MONDAY AFTERNOON DUE TO WESTERLY
WINDS...BUT ANOTHER FRONT SHOULD COOL US DOWN TO SLIGHTLY BELOW
NORMAL TUESDAY AND WEDNESDAY. TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 46 69 46 71 51 / 0 0 0 0 0
WACO, TX 46 71 41 71 49 / 0 0 0 0 0
PARIS, TX 44 69 43 69 47 / 0 0 0 0 0
DENTON, TX 42 69 41 71 50 / 0 0 0 0 0
MCKINNEY, TX 42 69 38 70 48 / 0 0 0 0 0
DALLAS, TX 47 69 46 71 51 / 0 0 0 0 0
TERRELL, TX 45 70 41 70 49 / 0 0 0 0 0
CORSICANA, TX 47 72 43 71 50 / 0 0 0 0 0
TEMPLE, TX 45 71 41 72 50 / 0 0 0 0 0
MINERAL WELLS, TX 41 71 40 71 47 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
75/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1003 PM CST TUE NOV 22 2011
.UPDATE...
SCATTERED TO BROKEN STRATUS THAT HAS LINGERED SINCE THIS AFTERNOON
IS FINALLY SHOWING SIGNS OF ERODING NOW THAT A DRIER AIRMASS AND
LOWER DEW POINTS OVER OKLAHOMA ARE FILTERING ACROSS THE RED RIVER
VALLEY. PER LOOK AT THE RUC/NAM/NAMM/AND SREF FAMILIES ON BUFKIT AND
AT THE CROSS-OVER TEMPERATURE METHOD...INDICATIONS ARE THAT CURRENT
TRENDS AND LOW TEMPERATURES FALLING TO...OR JUST BELOW AFTERNOON DEW
POINT TEMPERATURES WILL RESULT IN SOME FOG DEVELOPMENT OVERNIGHT AND
EARLY WEDNESDAY MORNING. FOG FORMATION SHOULD BECOME MORE EXPANSIVE
BY DAYBREAK AND THROUGH A BULK OF THE MORNING WEDNESDAY.
A MAJORITY OF NORTH TEXAS SAW RAINFALL THE PAST 24 HOURS...WITH A
FEW STRIPES OF HEAVIER RAINS BOTH ALONG AND JUST SOUTH OF THE RED
RIVER VALLEY AND ACROSS AREAS SOUTHEAST OF THE DALLAS-FORT WORTH
METROPLEX. THESE AREAS MAY SEE THE HIGHEST RISK OF FOG DEVELOPMENT
OVERNIGHT DUE TO HIGHER SATURATION.
FOR NOW...WE WILL MAINTAIN PATCHY FOG WORDING THROUGH 3 AM FOR ALL
OF NORTH TEXAS...THEN GO TO MORE AREAS OF FOG WITH PATCHY DENSE
FOG FROM THE PREDAWN HOURS THROUGH LATE MORNING WEDNESDAY...BEING
THAT IT IS GETTING INTO THE CRUX OF THE COOL SEASON. THE FORECAST
WILL BE A COMPROMISE BETWEEN THE MORE PESSIMISTIC RUC MODEL...AND
THE MORE OPTIMISTIC NAM/NAMM/SREF MODELS WHICH ONLY HAVE FOG
POTENTIAL THROUGH MID MORNING.
IT IS POSSIBLE A DENSE FOG ADVISORY MAY BE ISSUED EARLY WEDNESDAY
MORNING FOR PARTS OF NORTH TEXAS...BUT COVERAGE OF ANY DENSE FOG
IS UNCERTAIN AT THIS TIME AND WILL NOT ISSUE ANY ADVISORIES ON
THIS UPDATE.
05/
&&
.AVIATION...
CONCERNS...DURATION OF MVFR CIGS THIS EVENING AND POTENTIAL FOR
MVFR OR IFR FOG EARLY WEDNESDAY.
A LAYER OF BKN-OVC020 OFF TO THE NORTHWEST SHOULD CONTINUE TO
ADVECT SOUTHEASTWARD ACROSS THE METROPLEX TAF SITES THIS EVENING.
SUBSIDENCE WILL START ERODING THIS LAYER AFTER SUNSET...BUT
POTENTIAL EXISTS FOR IT TO LINGER THROUGH 03Z. AFTERWARD...EXPECT
SKIES TO GO SKC REST OF THE TAF FORECAST.
AS FOR MVFR OR IFR VIS AROUND DAYBREAK...CLEARING SKIES...LIGHT
WINDS...RECENT RAINS AND A SMALL T/TD SPREAD MAKES FOR A GOOD
SET-UP FOR FOG FORMING. THE BEST AREA FOR THIS TO HAPPEN WILL BE JUST
WEST OF THE METROPLEX...CLOSER TO THE CENTER OF THE SURFACE HIGH.
HAVE DECIDED TO ADD MVFR BR TO ALL TAF SITES AND CONTINUE TO
EVALUATE THIS POTENTIAL WHEN THE 00Z RUC/NAM ARE COMPLETE. 75
&&
.PREV DISCUSSION... /ISSUED 317 PM CST TUE NOV 22 2011/
ISENTROPIC DOWNGLIDE IS SLOWLY WORKING TO ERODE LOW LEVEL CLOUD
COVER AND THIS PROCESS SHOULD CONTINUE THROUGH THE EVENING HOURS.
CLOUDS SHOULD BE GONE FROM THE CWA BY MIDNIGHT...AND WITH
DECREASING WINDS...ABUNDANT SHALLOW MOISTURE FROM RECENT
RAIN...AND VERY DRY AIR ALOFT...CONDITIONS LOOK FAVORABLE FOR
PATCHY FOG. THE ONLY THING HOLDING BACK FOG DEVELOPMENT MAY BE
THAT THE WINDS ARE JUST A BIT TOO STRONG...SO FOG IN VALLEYS IS
PROBABLY MORE LIKELY. ASIDE FROM ANY MORNING FOG...EXPECT A VERY
NICE WEDNESDAY WITH PLEASANT TEMPERATURES...LIGHT WINDS AND LOTS
OF SUNSHINE. RADIATIONAL COOLING LOOKS IDEAL ON WEDNESDAY NIGHT
AND TEMPS SHOULD MEET DEWPOINTS AGAIN. HOWEVER LOW LEVEL MOISTURE
LOOKS A BIT TOO SHALLOW FOR FOG WEDNESDAY NIGHT. THANKSGIVING DAY
WILL ALSO BE PLEASANT...BUT SOUTH WINDS WILL INCREASE TO 10 TO 15
MPH IN THE AFTERNOON AS THE NEXT UPPER LEVEL TROUGH APPROACHES
FROM THE WEST. THESE INCREASING SOUTH WINDS WILL BRING GULF
MOISTURE/CLOUDS RAPIDLY BACK INTO THE AREA ON FRIDAY.
MODELS HAVE SLOWED DOWN THE PASSAGE OF THIS SYSTEM A BIT...BUT AM
CONCERNED THEY ARE STILL TOO FAST. THE ENERGY AT THE BASE OF THIS
TROUGH MAY CLOSE OFF AND TEMPORARILY STALL OFF THE BAJA COAST ON
THURSDAY...AS THERE IS QUITE A BIT OF DISTANCE BETWEEN THIS SYSTEM
AND WHAT WOULD BE THE KICKER TROUGH IN THE CENTRAL PACIFIC. WILL
PUSH BACK THE TIMING OF THIS SYSTEM 6-12 HOURS...AND THIS SUGGESTS
RAIN CHANCES WILL HOLD OFF UNTIL AFTER SUNSET FRIDAY BUT CONTINUE
INTO SATURDAY MORNING. WITH THE SLOWER TIMING...WE SHOULD GET
BETTER THETA-E AIR INTO THE REGION...ESPECIALLY IN THE EASTERN
ZONES. LAPSE RATES ARE NOT VERY IMPRESSIVE...SO ANY SEVERE WEATHER
THREAT SHOULD BE LIMITED BY WEAK INSTABILITY.
COLD FRONT WILL BLAST THROUGH DURING THE DAY SATURDAY WITH VERY
WINDY AND COOLER CONDITIONS IN ITS WAKE. AFOREMENTIONED UPPER
TROUGH SHOULD DEEPEN AND LUMBER ACROSS THE EASTERN US EARLY NEXT
WEEK. THIS WILL ENSURE A DRY NORTHERLY FLOW THROUGH MID WEEK.
LOOKS LIKE A BRIEF WARMUP ON MONDAY AFTERNOON DUE TO WESTERLY
WINDS...BUT ANOTHER FRONT SHOULD COOL US DOWN TO SLIGHTLY BELOW
NORMAL TUESDAY AND WEDNESDAY. TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 46 69 46 71 51 / 0 0 0 0 0
WACO, TX 46 71 41 71 49 / 0 0 0 0 0
PARIS, TX 44 69 43 69 47 / 0 0 0 0 0
DENTON, TX 42 69 41 71 50 / 0 0 0 0 0
MCKINNEY, TX 42 69 38 70 48 / 0 0 0 0 0
DALLAS, TX 47 69 46 71 51 / 0 0 0 0 0
TERRELL, TX 45 70 41 70 49 / 0 0 0 0 0
CORSICANA, TX 47 72 43 71 50 / 0 0 0 0 0
TEMPLE, TX 45 71 41 72 50 / 0 0 0 0 0
MINERAL WELLS, TX 41 71 40 71 47 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
75/05
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1222 PM EST WED NOV 23 2011
.SYNOPSIS...
DRY HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST TONIGHT...RESULTING
IN BY WARM AFTERNOONS AND CHILLY MORNINGS INTO THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM EST WEDNESDAY...
LATEST HRRR AND 4KN NAM GUIDANCE SHOWING 850 MB WINDS INCREASING
TO THE 55-65 KNOT RANGE AT THE HIGHER ELEVATIONS BY 21Z/4PM WITH
THE STRONGEST WINDS ALONG THE BLUE RIDGE SOUTH OF ROANOKE. EVEN
THE 10 METER WIND GUSTS ARE FORECAST TO BE IN THE 50 TO 60 KNOT
RANGE ALONG THIS CORRIDOR. WIND DIRECTION WILL BE 330-340 DEGREES
BY THAT TIME WHICH IS ALSO FAVORABLE TO GET INCREASED WIND SPEEDS
FROM CHANNELING AT FANCY GAP. WILL BE EXPANDING HIGH WIND WARNING
TO INCLUDE ALL BLUE RIDGE COUNTIES AND THROUGH BATH COUNTY
VIRGINIA. HAVE ALSO EXPANDED WIND ADVISORY FOR THE REST OF THE
COUNTIES WEST OF THE BLUE RIDGE.
SHOWERS AND CLOUDS HAVE CLEARED OUT OF THE EASTERN COUNTY WARNING
AREA. HAVE UPDATED TO REMOVE CHANCE OF RAIN IN THE EAST. NO
CHANGES TO TEMPERATURES NEEDED TO THIS TIME.
SURFACE HIGH BUILDS IN FROM THE WEST TONIGHT WITH WINDS FINALLY
DIMINISHING AFTER MIDNIGHT UNDER CLEARING SKIES. ALTHO COLD AIR
QUITE LIMITED WITH THIS SYSTEM...WILL BE TRICKY AS TO THE DEGREE OF
DECOUPLING LATE WITH THE RIDGE STILL JUST TO THE WEST BY MORNING.
CERTAINLY LOOKS LIKE THE DEEPER VALLEYS COULD CHASE DOWN CLOSE TO
FREEZING BUT EXPECT RIDGES AND EASTERN SPOTS TO STAY ABOVE MOS AS
LIGHT MIXING PERSISTS SO BASICALLY KEPT THEM IN THE MID TO UPPER 30S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 255 AM EST WEDNESDAY...
NICE WEATHER RETURNS WITH ANOTHER GOOD WARMUP THRU FRIDAY AS HIGH
PRESSURE BUILDS OVERHEAD FOR THANKSGIVING AND THEN SINKS TO THE
SOUTH FRIDAY ALLOWING FOR ANOTHER ROUND OF WARM ADVECTION. MAY SEE
SOME HIGH CLOUDS CUT THRU THE RIDGE BY FRIDAY BUT GIVEN THE
STRENGTH OF THE S/W RIDGING EXPECTING MAINLY SUNNY SKIES AND
RATHER LIGHT WINDS. DID LOWER HIGHS BACK JUST A LITTLE ON THU PER
ONLY LIGHT MIXING UNDER THE RIDGE DESPITE WARMING ALOFT. OTRW KEPT
IT QUITE WARM FRIDAY WITH TEMPS MOSTLY IN THE 60S. LOOKS LIKE
QUITE A RANGE OF LOWS THU NIGHT AS WARMING/BREEZES ALOFT DEVELOP
ON THE RIDGES WHILE THE VALLEYS FALL TO BELOW FREEZING GIVEN DRY
AIR IN PLACE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM EST TUESDAY...
SURFACE HIGH PRESSURE WILL REMAIN ALONG THE EAST COAST FRIDAY NIGHT
THEN SLOWLY DRIFT OUT TO SEA OVER THE WEEKEND. AN UPPER LEVEL RIDGE
WILL ACCOMPANY THE SURFACE HIGH ALLOWING TEMPERATURES TO WARM TO
AROUND 10F ABOVE NORMAL SATURDAY AND POSSIBLY SUNDAY. TEMPERATURES
DROP BELOW NORMAL MONDAY AND TUESDAY WITH HIGHS MAINLY IN THE 40S.
MODELS HAVE BEEN PERSISTENT WITH DEVELOPING A CUTOFF SOUTHERN STREAM
LOW EITHER SUNDAY OR MONDAY. THIS CUTOFF LOW WILL TAP BOTH GULF AND
ATLANTIC MOISTURE. WAVES AHEAD OF THIS LOW WILL TRACK NORTHWARD AND
PARALLEL IF NOT DIRECTLY OVER THE SOUTHERN APPALACHIANS. THIS WILL
BRING PERIODS OF RAIN...HEAVY AT TIMES...TO THE AREA LATE THIS
WEEKEND AND/OR EARLY NEXT WEEK. IF THIS UPPER LOW IS IN THE VICINITY
OF THE AREA MONDAY INTO TUESDAY...A MIXTURE OF RAIN/SNOW/SLEET IS
POSSIBLE ALONG AND WEST OF THE BLUE RIDGE.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1220 PM EST WEDNESDAY...
MVFR CEILINGS REMAINED OVER THE MOUNTAINS WEST OF THE BLUE RIDGE
THIS AFTERNOON. A FEW POCKETS OF IFR CEILINGS AS ISOLATED SHOWERS
WERE ALSO OBSERVED. MODELS GRADUALLY ERODE LOW LEVEL MOISTURE
DURING THE NEXT 12 TO 24 HOURS. EXPECT VFR CONDITIONS EVEN AT BLF
AND LWB BY 00Z TONIGHT.
STRONG GUSTY NORTHWEST TO NORTH WINDS WILL CONTINUE THROUGH THE
EVENING. WIND GUSTS AT HIGHER ELEVATIONS MAY BE AS HIGH AS 50
KNOTS. AS HIGH PRESSURE BUILDS INTO THE REGION TONIGHT AND
THURSDAY WINDS WILL DIMINISH.
HIGH PRESSURE AND DRY CONDITIONS WILL COVER THE REGION THROUGH
SATURDAY WITH NEXT THREAT OF SUB VFR CONDITIONS A POSSIBILITY ON
SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007-009>014-
018.
HIGH WIND WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ015>017-
019-020-022>024-032>035.
NC...HIGH WIND WARNING UNTIL MIDNIGHT EST TONIGHT FOR NCZ001>003-
018-019.
WV...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR WVZ042>045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/JH
SHORT TERM...JH
LONG TERM...RCS
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1002 AM EST WED NOV 23 2011
.SYNOPSIS...
DRY HIGH PRESSURE QUICKLY BUILDS IN FROM THE WEST TONIGHT...RESULTING
IN BY WARM AFTERNOONS AND CHILLY MORNINGS INTO THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM EST WEDNESDAY...
LATEST HRRR AND 4KN NAM GUIDANCE SHOWING 850 MB WINDS INCREASING
TO THE 55-65 KNOT RANGE AT THE HIGHER ELEVATIONS BY 21Z/4PM WITH
THE STRONGEST WINDS ALONG THE BLUE RIDGE SOUTH OF ROANOKE. EVEN
THE 10 METER WIND GUSTS ARE FORECAST TO BE IN THE 50 TO 60 KNOT
RANGE ALONG THIS CORRIDOR. WIND DIRECTION WILL BE 330-340 DEGREES
BY THAT TIME WHICH IS ALSO FAVORABLE TO GET INCREASED WIND SPEEDS
FROM CHANNELING AT FANCY GAP. WILL BE EXPANDING HIGH WIND WARNING
TO INCLUDE ALL BLUE RIDGE COUNTIES AND THROUGH BATH COUNTY
VIRGINIA. HAVE ALSO EXPANDED WIND ADVISORY FOR THE REST OF THE
COUNTIES WEST OF THE BLUE RIDGE.
SHOWERS AND CLOUDS HAVE CLEARED OUT OF THE EASTERN COUNTY WARNING
AREA. HAVE UPDATED TO REMOVE CHANCE OF RAIN IN THE EAST. NO
CHANGES TO TEMPERATURES NEEDED TO THIS TIME.
SURFACE HIGH BUILDS IN FROM THE WEST TONIGHT WITH WINDS FINALLY
DIMINISHING AFTER MIDNIGHT UNDER CLEARING SKIES. ALTHO COLD AIR
QUITE LIMITED WITH THIS SYSTEM...WILL BE TRICKY AS TO THE DEGREE OF
DECOUPLING LATE WITH THE RIDGE STILL JUST TO THE WEST BY MORNING.
CERTAINLY LOOKS LIKE THE DEEPER VALLEYS COULD CHASE DOWN CLOSE TO
FREEZING BUT EXPECT RIDGES AND EASTERN SPOTS TO STAY ABOVE MOS AS
LIGHT MIXING PERSISTS SO BASICALLY KEPT THEM IN THE MID TO UPPER 30S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 255 AM EST WEDNESDAY...
NICE WEATHER RETURNS WITH ANOTHER GOOD WARMUP THRU FRIDAY AS HIGH
PRESSURE BUILDS OVERHEAD FOR THANKSGIVING AND THEN SINKS TO THE
SOUTH FRIDAY ALLOWING FOR ANOTHER ROUND OF WARM ADVECTION. MAY SEE
SOME HIGH CLOUDS CUT THRU THE RIDGE BY FRIDAY BUT GIVEN THE
STRENGTH OF THE S/W RIDGING EXPECTING MAINLY SUNNY SKIES AND
RATHER LIGHT WINDS. DID LOWER HIGHS BACK JUST A LITTLE ON THU PER
ONLY LIGHT MIXING UNDER THE RIDGE DESPITE WARMING ALOFT. OTRW KEPT
IT QUITE WARM FRIDAY WITH TEMPS MOSTLY IN THE 60S. LOOKS LIKE
QUITE A RANGE OF LOWS THU NIGHT AS WARMING/BREEZES ALOFT DEVELOP
ON THE RIDGES WHILE THE VALLEYS FALL TO BELOW FREEZING GIVEN DRY
AIR IN PLACE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM EST TUESDAY...
SURFACE HIGH PRESSURE WILL REMAIN ALONG THE EAST COAST FRIDAY NIGHT
THEN SLOWLY DRIFT OUT TO SEA OVER THE WEEKEND. AN UPPER LEVEL RIDGE
WILL ACCOMPANY THE SURFACE HIGH ALLOWING TEMPERATURES TO WARM TO
AROUND 10F ABOVE NORMAL SATURDAY AND POSSIBLY SUNDAY. TEMPERATURES
DROP BELOW NORMAL MONDAY AND TUESDAY WITH HIGHS MAINLY IN THE 40S.
MODELS HAVE BEEN PERSISTENT WITH DEVELOPING A CUTOFF SOUTHERN STREAM
LOW EITHER SUNDAY OR MONDAY. THIS CUTOFF LOW WILL TAP BOTH GULF AND
ATLANTIC MOISTURE. WAVES AHEAD OF THIS LOW WILL TRACK NORTHWARD AND
PARALLEL IF NOT DIRECTLY OVER THE SOUTHERN APPALACHIANS. THIS WILL
BRING PERIODS OF RAIN...HEAVY AT TIMES...TO THE AREA LATE THIS
WEEKEND AND/OR EARLY NEXT WEEK. IF THIS UPPER LOW IS IN THE VICINITY
OF THE AREA MONDAY INTO TUESDAY...A MIXTURE OF RAIN/SNOW/SLEET IS
POSSIBLE ALONG AND WEST OF THE BLUE RIDGE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS OF 600 AM EST WEDNESDAY...
ANOTHER BROKEN BAND OF SHOWERS MOVING ACROSS THE MOUNTAINS ATTM
JUST AHEAD OF THE ACTUAL COLD FRONT NOW CROSSING THE WESTERN
SLOPES. EXPECT MOST OF THESE SHOWERS TO DRY UP CROSSING THE BLUE
RIDGE GIVEN WESTERLY FLOW BUT STILL ENOUGH TO CAUSE SOME BRIEF
REDUCTIONS TO MVFR VSBYS AND IFR CIGS FROM KBCB WEST EARLY ON.
MAY INCLUDE A VCSH AT BOTH KROA AND KLYH AS WELL FOR SOME OF THIS
TO SPILLOVER OTRW LEAVING OUT ADDED SHRA MENTION OUT EAST THRU THE
PERIOD.
CIGS WILL BE GOING DOWN TO IFR OR LOWER BEHIND THE FRONT WITH
STRONG UPSLOPE LATER THIS MORNING AT KBLF...WHILE KBCB/KLWB STAY
MVFR. SOME ADDITIONAL -RA OR DRIZZLE ALSO POSSIBLE...MAINLY AT
KBLF THRU EARLY AFTERNOON OTRW EXPECT DECREASING SHRA AS THE FRONT
PUSHES TO THE EAST.
THE AVIATION CONDITIONS BY AFTERNOON WILL NOT BE IDEAL AS WE ARE
LOOKING AT A STRONG LOW LVL JET COMING IN WITH STRONG PRESSURE
RISES. THIS WILL LEAD TO GUSTS UP TO 30 TO 40 KNOTS BY MIDDAY INTO
THE AFTN...ESPECIALLY AT KBCB/KROA. DOWNSLOPE DRYING WILL BRING
VFR CONDITIONS TO THE TAF SITES EXCEPT KBLF/KLWB BY EARLY
AFTN...WITH VFR RETURNING TO THE BLF/KLWB CORRIDOR IN THE EVENING
WHEN WINDS START TO SUBSIDE SOME.
HIGH PRESSURE AND DRY CONDITIONS WILL COVER THE REGION THROUGH
SATURDAY WITH NEXT THREAT OF SUB VFR CONDITIONS A POSSIBILITY
SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007-009>014-
018.
HIGH WIND WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ015>017-
019-020-022>024-032>035.
NC...HIGH WIND WARNING UNTIL MIDNIGHT EST TONIGHT FOR NCZ001>003-
018-019.
WV...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR WVZ042>045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/JH
SHORT TERM...JH
LONG TERM...RCS
AVIATION...AMS/JH/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
537 PM CST THU NOV 24 2011
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
236 PM CST THU NOV 24 2011
MAIN FORECAST CONCERNS THIS PACKAGE...RAIN CHANCES FRI NIGHT/SAT...
WINDS SAT...RAIN/SNOW CHANCES SAT NIGHT...TEMPERATURES THRU THE
PERIOD.
DATA ANALYSIS AT 18Z HAD TIGHTER PRESSURE GRADIENT BETWEEN HIGH
PRESSURE OVER THE SOUTHEAST CONUS AND LOW PRESSURE EAST OF LK
WINNIPEG OVER THE AREA. BRISK SOUTH WINDS ACROSS MUCH OF MN/IA/WI AT
MID-DAY. THESE WINDS...COMBINED WITH DIURNAL WARMING AND SOUTHWEST-
WEST FLOW IN THE 925-700MB LAYERS HELPING TO ERODE/ADVECT THE LOW
STRATUS CLOUDS EAST AND OUT OF THE FCST AREA. TEMPS RESPONDING TO
THE WARM ADVECTION/MOSTLY SUNNY SKIES WITH NOONTIME READINGS IN THE
MID 40S TO MID 60S FROM NORTHEAST WI TO SOUTHWEST IA...SOME 10-20F
ABOVE NORMAL AND NEAR RECORD HIGHS AT SOME LOCATIONS ON THIS
THANKSGIVING DAY.
24.12Z MODELS LOOK TO HAVE INITIALIZED WELL AND OFFER RATHER SIMILAR
SOLUTIONS FOR TONIGHT INTO SAT. MODELS GRADUALLY CONVERGING ON A
COMMON/TIGHTER CONSENSUS SOLUTION WITH THE TROUGH/LOW TO MOVE ACROSS
THE REGION FRI NIGHT THRU SAT NIGHT. DPROG/DT OF 500MB HGTS AT
24.12Z SHOWED MODEL RUNS OF 22.12Z AND 23.12Z VERIFIED QUITE WELL
ACROSS NOAM/EASTERN PAC WITH BETTER RUN-TO-RUN CONSISTENCY BY ECMWF.
TREND IS TOWARD A COMPROMISE OF THE EARLIER RUNS. MODELS CONTINUE TO
CONVERGE TOWARD A COMMON SOLUTION TONIGHT THRU SAT AS THE TROUGH/
ENERGY MOVES FROM NEAR THE WEST COAST TO THE WESTERN PLAINS BY 00Z
SAT THEN TO THE MID/UPPER MS VALLEY BY 00Z SUN. TREND GENERALLY
FAVORS THE SLOWER OF THE EARLIER RUNS WITH A COMPROMISE ON THE
STRENGTH OF THE TROUGH. DIFFERENCES REMAIN BETWEEN THE MODELS FOR
SAT NIGHT INTO SUN NIGHT WITH A MORE CONSOLIDATED LOW/TROUGH OVER
THE CENTRAL GREAT LAKES /GFS/NAM/ VS. A MORE NORTHERN/SOUTHERN
STREAM...OPEN TROUGH SPLIT OF THE ENERGY /ECMWF/GEM/UKMET/. GFS
ENSEMBLE MEAN SPLITS THE DIFFERENCE OF THE 2 GROUPS SAT NIGHT/SUN.
ECMWF LOOKS TO HAVE SLIGHTLY BETTER RUN-TO-RUN CONSISTENCY IN THE
LATER PART OF THE SHORT-TERM PERIOD. CHECK OF OBS VS. MODEL DATA AT
18Z SHOWED MODELS ALL REASONABLE WITH THE SFC MASS FIELDS OVER THE
CENTRAL CONUS. PER WV IMAGERY...ALL APPEARED REASONABLE WITH THE
SHORTWAVE DETAILS OVER NOAM/EASTERN PAC. THUS AGAIN NO CLEAR
DETERMINISTIC MODEL FAVORITE. WITH THE TRENDS TOWARD A COMPROMISE
SOLUTION...AT LEAST THRU 60HRS...FAVORED THE MODEL/ENSEMBLE
COMPROMISE SOLUTION. GIVEN THE CONTINUED DETAIL DIFFERENCES...SHORT-
TERM FCST CONFIDENCE AVERAGE AT BEST THIS CYCLE.
IN THE SHORT TERM...FIRST CONCERN IS RETURN OF MOISTURE IN 950-900MB
LAYER TONIGHT AND IF IT WILL MANIFEST AS ANOTHER LOW STRATUS DECK
OR NOT. SEE AVIATION DISCUSSION BELOW FOR MORE DETAILS ON POTENTIAL
LOW CLOUDS/BR TONIGHT AS THE LOWER LEVEL MOISTURE RETURNS. DID SHOW
INCREASING CLOUDS IN THE GRIDS LATER TONIGHT AS MOISTURE/BROAD LIFT
ABOVE 500MB AHEAD OF THE TROUGH ADVANCING THRU THE ROCKIES INCREASE
OVER THE AREA. BRISK WINDS TONIGHT AND THESE CLOUDS TO MAKE FOR A
SEASONABLY MILD NIGHT ACROSS THE AREA TONIGHT...WITH LOWS ABOVE THE
NORMAL HIGHS FOR THE DATE. MOISTURE/LIFT CONTINUE TO INCREASE OVER
THE AREA FRI WITH THICKENING CLOUDS. QUESTION REMAINS WILL A SMALL
-RA CHANCE BE NEEDED ACROSS THE SOUTH END OF THE FCST AREA LATE IN
THE AFTERNOON. MODELS MAINTAIN A DRY LAYER BETWEEN 850-650MB OVER
THE SOUTH END OF THE FCST AREA FRI AFTERNOON...WITH MODEST LIFT AT
BEST AT OR ABOVE 500MB. WILL MAINTAIN THE DRY FRI AFTERNOON FCST FOR
NOW. MOISTURE/850-500MB THERMO-DYNAMIC FORCING/LIFT INCREASE QUICKLY
FRI EVENING...MAXIMIZING OVER THE FCST AREA LATE FRI NIGHT INTO
EARLY SAT MORNING. THIS WITH INCREASING 500-300MB PV ADVECTION AND
300MB AGEOSTROPHIC FLOW/DIVERGENCE IN RIGHT ENTRANCE REGION OF A
110KT JET AHEAD OF THE TROUGH AXIS. PW VALUES INCREASE INTO THE 0.75
TO 1 INCH RANGE OVER THE SOUTHEAST 3/4 OF THE FCST AREA AS WELL BY
12Z SAT. THUS RAISED RAIN CHANCE THRU FRI NIGHT...INTO THE 60-85
PERCENT RANGE AFTER MIDNIGHT. RAISED RAIN CHANCES SAT MORNING INTO
THE 60-80 PERCENT RANGE OVER THE EAST HALF OF THE FCST AREA. LEFT
RAIN CHANCES IN THE 30-50 PERCENT RANGE OVER THE WEST THIRD OF THE
FCST AREA SAT MORNING AS BETTER CONSENSUS FOR THE COLD FRONT AND
925-850MB TROUGH AXIS TO BE MOVING EAST OF THE MS RIVER DURING THE
MORNING. DRIER AIR AND COLD ADVECTION/SUBSIDENCE TO BE SPREADING
INTO THE AREA BEHIND THE SFC-850MB FRONT. QUESTION FOR SAT
AFTERNOON BECOMES HOW QUICKLY WILL THE COLUMN COOL ENOUGH FOR ANY
PRECIP TO MIX WITH/CHANGE TO SNOW. NAM MOST ROBUST BRINGING IN THE
COLD AIR. TEMPS DO FALL DURING THE DAY SAT IN THE STRONG POST
FRONTAL COLD ADVECTION BUT MODEL CONSENSUS KEEPS THE BOUNDARY LAYER
TEMPS DURING THE AFTERNOON IN THE UPPER 30S/AROUND 40. THIS A BIT
WARM FOR A COMPLETE CHANGE TO -SN OR ACCUMULATIONS...GIVEN BULK OF
FORCING/LIFT IS NORTH/EAST OF THE AREA AND PRECIP RATES EXPECTED TO
BE ON THE LIGHT SIDE BY SAT AFTERNOON. CONTINUED A -RA/-SN MIX FOR
MUCH OF THE AREA SAT AFTERNOON. STRONGEST OF SFC-850MB COLD
ADVECTION MOVES ACROSS THE AREA SAT MORNING WHILE STRONGEST OF SFC-
925MB GRADIENT WINDS MOVE ACROSS THE AREA CENTERED ON SAT NIGHT.
STRONG/GUSTY NORTHWEST WINDS TO SPREAD ACROSS THE AREA SAT/SAT NIGHT
BUT AT THIS TIME LOOK TO REMAIN BELOW ADVISORY CRITERIA. DID
INCREASE WINDS SAT NIGHT INTO SUN WITH GRADIENT REMAINING TIGHT AND
CONTINUING LOW LEVEL COLD ADVECTION OVER THE AREA. BOUNDARY LAYER
COOLS ENOUGH FOR ALL SNOW SAT EVENING. NAM/GFS SHOWING MORE WRAP
AROUND/DEFORMATION BAND PRECIP ON THE BACK SIDE OF THE SYSTEM WITH A
500MB LOW OVER EASTERN WI/LK MI WHILE MORE OPEN/POSITIVE TILT WAVE
SOLUTION OF ECMWF/GEM/UKMET MUCH WEAKER WITH FORCING/LIFT/PRECIP
PRODUCTION BEHIND THE TROUGH AXIS SAT NIGHT/SUN MORNING. LEFT BULK
OF -SN/-RA CHANCES SAT NIGHT IN THE 20-50 PERCENT RANGE FOR NOW...
ONLY CARRYING LIKELY ALONG/NORTH OF HIGHWAY 29 ACROSS CENTRAL WI.
DID LINGER A 20 PERCENT -SN CHANCE OVER THE EAST HALF OF THE FCST
AREA SUN MORNING TO HONOR NAM/GFS SOLUTIONS. HIGH PRESSURE/SHORTWAVE
RIDGING ALOFT BUILD IN FOR LATER SUN/SUN NIGHT.
FAVORED A BLEND OF THE NUMERICAL TEMP GUIDANCE FOR MOST LOWS/HIGHS
TONIGHT THRU SUN NIGHT. DID FAVOR WARMER OF GUIDANCE LOWS TONIGHT
WITH BRISK SOUTH WINDS AND INCREASE OF HIGH CLOUDS AFTER MIDNIGHT.
CONTINUED THE TREND OF HIGHS SAT AROUND 15Z THEN FALLING TEMPS
BEHIND THE COLD FRONT THE REST OF THE DAY. WITH SFC RIDGE AXIS OVER
THE AREA SUN NIGHT FAVORED COOLER OF GUIDANCE LOWS.
.LONG TERM...MONDAY THROUGH THURSDAY
236 PM CST THU NOV 24 2011
24.00Z MEDIUM RANGE MODELS SHOW QUITE A BIT OF VARIABILITY ALREADY
MONDAY WITH THE PROGRESSIVENESS OF THE TROUGHING OVER THE EASTERN
CONUS. RUN-TO-RUN CONSISTENCY LEAVES QUITE A BIT TO BE DESIRED TOO.
MODELS BETTER/MORE CONSISTENT WITH THE NEXT TROUGH DROPPING INTO
THE NORTHERN PLAINS BUT TREND IS A BIT FLATTER/FASTER WITH THIS
FEATURE. MODELS REMAIN FASTER/FLATTER WITH THIS FEATURE TUE WITH A
TREND TOWARD MORE ZONAL FLOW OVER THE NORTH-CENTRAL AND NORTHWEST
CONUS. STILL PLENTY OF DIFFERENCES WITH EAST/SOUTHEAST CONUS LOW.
GFS/ECMWF SOLUTIONS DIVERGE FOR WED WITH TIMING ISSUES OF A
STRONGER SHORTWAVE THRU BROAD NORTHWEST FLOW OVER WESTERN NOAM.
SOLUTIONS TREND MORE SIMILAR WITH A SHORTWAVE TROUGH MOVING ACROSS
THE WESTERN GREAT LAKES THU. RUN-TO-RUN CONSISTENCY REMAINS BELOW
AVERAGE WED/THU...TIED TO GLOBAL FLOW FORCING MECHANISMS AS
DISCUSSED BY MID SHIFT FORECASTER. UNTIL THIS SETTLES DOWN...RUN-TO-
RUN CONSISTENCY BEYOND ABOUT DAY 5 CAN BE EXPECTED TO REMAIN BELOW
AVERAGE. LONG-TERM FCST CONFIDENCE AGAIN BELOW AVERAGE WITH ALL THE
BETWEEN MODEL AND RUN-TO-RUN VARIABILITY...THUS WILL LEAVE DAY 4-7
GRIDS CLOSE TO A THE MODEL/ENSEMBLE CONSENSUS. WITH A DRIER WEST TO
NORTHWEST FLOW ALOFT AND MAIN SHORTWAVE ENERGY LOOKING TO PASS NORTH
OF THE AREA...DAYS 4-7 TRENDING TO BE A MOSTLY DRY PERIOD.
REASONABLE MODEL CONSENSUS FOR A FRONT TO PUSH ACROSS THE AREA MON
BUT MOISTURE LIMITED AND SFC FRONT PASSES WELL AHEAD OF THE MID
LEVEL TROUGH. CONSENSUS FOR SFC HIGH PRESSURE TO BUILD OVER THE
REGION FOR TUE. MAIN SHORTWAVE ENERGY WED OR THU /DEPENDS ON WHICH
MODEL WOULD BE MORE CORRECT WITH TIMING/ PASSES NORTH OF THE AREA
WITH ANOTHER FRONT TO PUSH ACROSS THE UPPER MIDWEST ONE OF THE DAYS.
24.12Z GFS/ECMWF PUSH A STRONGER TROUGH/FRONT TOWARD/ACROSS THE
REGION THU...WITH A SMALL -RA/-SN CHANCE THAT DAY REASONABLE FOR
NOW. TEMPERATURES FOR DAYS 4-7 LOOKING TO BE NEAR/A BIT ABOVE NORMAL
AND THIS WELL TRENDED WITH THE MODEL CONSENSUS GRIDS.
&&
.AVIATION...TONIGHT AND FRIDAY
537 PM CST THU NOV 24 2011
BIGGEST CONCERN REMAINS ON THE POTENTIAL FOR MORE STRATUS
DEVELOPMENT TONIGHT AND LOW LEVEL WIND SHEAR. SATELLITE SHOWING
JUST HIGH CLOUDS ACROSS THE AREA...BUT PRESSURE GRADIENT RATHER
TIGHT. KARX VAD WIND PROFILE SHOWS 45 KNOT WINDS AT 2K FEET AND
MODELS CONTINUE TO SHOW STRONG LOW LEVEL JET OF 45 TO 55 KNOTS
THROUGH THE EVENING HOURS. DO EXPECT WINDS TO SETTLE DOWN IN THE
VALLEY LOCATION AT KLSE TO AROUND 11 KNOTS AND THUS HAVE CONTINUED
THE LOW LEVEL WIND SHEAR. AT KRST...QUESTION WILL BE IF SURFACE
WINDS CONTINUE TO GUST THIS EVENING AND WITH THE TIGHT PRESSURE
GRADIENT SO FEEL THERE WILL SOME GUSTS AND THUS DID NOT MENTION THE
LLWS. BOTH THE 24.12Z NAM/GFS AND THE 24.21Z RUC DO SHOW A BAND OF
925 MB MOISTURE SURGING NORTHWARD OUT OF THE PLAINS LATE TONIGHT.
QUESTION WILL BE IF IT MANIFESTS ITSELF IN THE FORM OF STRATUS.
WITH THE STRONG LOW LEVEL JET...EXPECTATIONS ARE THIS MOISTURE
WILL ONLY RESULT IN VISIBILITIES OF 4SM-6SM. HOWEVER...WILL HAVE
TO MONITOR THROUGHOUT THE EVENING. FOR NOW KEPT THE SCT005-010
DECK AFTER 09Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
236 PM CST THU NOV 24 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
250 PM CST WED NOV 23 2011
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
250 PM CST WED NOV 23 2011
MAIN FORECAST CONCERNS THIS PACKAGE...RAIN CHANCES CENTERED ON FRI
NIGHT/SAT...WINDS SAT...TEMPERATURES THRU THE PERIOD.
18Z DATA ANALYSIS HAD LOW PRESSURE MOVING EAST ACROSS CENTRAL
CANADA AND HIGH PRESSURE OVER MO TO EAST TX. VIS IMAGERY/SFC OBS
SHOWED LOW STRATUS REMAINED TRAPPED UNDER AN INVERSION NEAR 925MB
ACROSS MUCH OF WI/IA AND SOUTHEAST MN. LAPS SOUNDINGS AND PILOT
REPORTS INDICATING THE MOISTURE/CLOUDS RATHER SHALLOW UNDER THE
INVERSION. MOST MODELS...EXCEPT FOR GFS...DOING A DECENT JOB
DEPICTING THE LOW LEVEL MOISTURE/CLOUDS THIS MORNING. INCREASING
PRESSURE GRADIENT OVER THE AREA AND WESTERLY FLOW IN THE 925-700MB
LAYER FINALLY STARTING TO ERODE/ADVECT THE LOW LEVEL MOISTURE/CLOUDS
EAST AT MID-DAY...WITH CLEARING WORKING INTO THE WEST END OF THE
FCST AREA.
23.12Z MODELS LOOK TO HAVE INITIALIZED WITHOUT SIGNIFICANT ERRORS
AND OFFER RATHER SIMILAR SOLUTIONS FOR TONIGHT THRU FRI. SOLUTIONS
DIVERGE WITH STRENGTH/TIMING OF THE TROUGH FRI NIGHT INTO SAT NIGHT.
OVERALL TREND LOOKS TO DEVELOP A STRONGER SFC LOW NORTH OF THE AREA
FRI NIGHT/SAT...AND SHUNTS THE DEEPER MOISTURE/PRECIP AHEAD OF IT
A BIT FURTHER EAST. STRONGER LOW RESULTS IN A STRONGER GRADIENT/LOW
LEVEL COLD ADVECTION BEHIND IT ON SAT. DPROG/DT OF 500MB HGTS AT
23.12Z SHOWED MODEL RUNS OF 21.12Z AND 22.12Z VERIFIED QUITE WELL
ACROSS NOAM/EASTERN PAC...BUT ALL WERE A BIT WEAK WITH THE TROUGH
OVER THE OH VALLEY. THRU THU MODEL TRENDS FAVOR THE MORE PROGRESSIVE
OF EARLIER SOLUTIONS WITH A TROUGH EXITING OFF THE EAST COAST. TREND
IS A BIT SLOWER/STRONGER WITH A FEATURE OVER THE CA BAJA AT 00Z FRI.
FOR THU NIGHT/FRI MODELS TRENDING TOWARD A SOLUTION OF MORE
NORTHERN-SOUTHERN STREAM SEPARATION AS THE SHORTWAVE ENERGY COMES
EAST INTO MT TO WEST TX. TREND AT 00Z SAT IS ALSO A BIT SLOWER WITH
THIS ENERGY. BY 00Z SUN MODELS IN TWO CAMPS WITH THE TROUGHING OVER
THE MID/UPPER MS VALLEY...NAM/GFS FASTER...ECMWF/GEM SLOWER. ALL BUT
GEM FASTER THAN THEIR EARLIER RUNS BY SAT NIGHT...AND LOOK TO KEEP
THE NORTHERN/SOUTHERN STREAM PIECES OF ENERGY MORE SEPARATE UNTIL
THE TOUGH AXIS PASSES EAST OF THE AREA. SOMEWHAT BETTER RUN-TO-RUN
CONSISTENCY TONIGHT THRU SAT TO ECMWF. CHECK OF OBS VS. MODEL DATA
AT 18Z SHOWED MODELS ALL REASONABLE WITH THE SFC MASS FIELDS OVER
THE NORTH-CENTRAL CONUS. MOST...BUT FOR GFS...REMAINED GOOD WITH THE
TRAPPED LOW LEVEL MOISTURE/CLOUDS OVER THE REGION. PER WV IMAGERY...
ALL MODELS LOOKED REASONABLE WITH THE SHORTWAVE DETAILS OVER NOAM/
EASTERN PAC. NO CLEAR MODEL FAVORITE THIS CYCLE...BUT WITH ECMWF
OFFERING SOMEWHAT BETTER RUN-TO-RUN CONSISTENCY FAVORED A MODEL/
ENSEMBLE BLEND WEIGHTED TOWARD THE ECMWF. HOWEVER GIVEN THE DETAIL
DIFFERENCES...SHORT-TERM FCST CONFIDENCE AVERAGE THIS CYCLE.
FOR THE SHORT TERM...SFC-850MB GRADIENT CONTINUES TO INCREASE OVER
THE AREA TONIGHT...WITH A DRY WESTERLY COMPONENT OF THE FLOW. LOW
CLOUDS WILL FINALLY CLEAR THE AREA LATE THIS AFTERNOON/EARLY THIS
EVENING. MODEL SOUNDINGS/X-SECTIONS THEN INDICATE A RATHER DEEP...
DRY AIRMASS OVER THE AREA FOR LATER THIS EVENING INTO THU NIGHT AS
MID LEVEL SHORTWAVE RIDGING BUILDS OVER THE AREA. MODERATE PRESSURE
GRADIENT REMAINS OVER THE AREA FOR TONIGHT INTO THU NIGHT...TO LIMIT
ANY FOG POTENTIAL TONIGHT AND FOR SOME LOW LEVEL MIXING ON THU.
925MB TEMPS ON THU PROGGED TO BE IN THE +8 TO +13C RANGE. QUESTION
IS DEPTH OF MIXING. MODEL SOUNDINGS ONLY INDICATE MIXING TO ABOUT
950MB. EVEN SO...WITH PLENTY OF SUNSHINE ON THU HIGHS EXPECTED TO BE
IN THE 50S...SOME 15-20 DEGREES ABOVE NORMAL. SOUTHWEST GRADIENT
WINDS CONTINUE THU NIGHT...FOR LOWS REMAINING MUCH ABOVE NORMAL
UNDER INCREASING HIGH CLOUDS. TEMPS REMAIN MILD FRI WITH THE WARM
START AND SOUTHWEST FLOW AHEAD OF THE APROACHING LOW/TOUGH. GFS NOW
THE LONE MODEL PRODUCING SOME -RA OVER THE SOUTHEAST PARTS OF THE
FCST AREA FRI AFTERNOON. GFS MODEL SOUNDINGS AND X-SECTIONS INDICATE
INITIAL FORCING/LIFT IS ABOVE 500MB WHILE COLUMN BELOW 500MB IS
QUITE DRY THRU 00Z SAT. REMOVED SMALL FRI AFTERNOON -RA CHANCE FROM
THE SOUTH END OF THE FCST AREA. DEEPER MOISTURE/LIFT AHEAD OF THE
TROUGH ARRIVE FRI NIGHT...BUT PLENTY OF DETAIL DIFFERENCES WITH THE
DEPTH/STRENGTH/TIMING OF THIS MOISTURE/FORCING/LIFT. GIVEN THESE
DETAIL DIFFERENCES...ESPECIALLY WITH DEPTH OF MOISTURE/SATURATION OF
THE COLUMN AHEAD OF THE SFC-MID LEVEL TROUGH AXIS...NOT MUCH FOR
CONFIDENCE TO MAKE CHANGES TO PRECIP CHANCES IN THE FRI NIGHT/SAT
FCST GRIDS. ECMWF WOULD IMPLY RAIN CHANCES NEED TO BE RAISED FRI
NIGHT/SAT. MANY OF THE OTHER MODELS WOULD INDICATE THE CHANCES NEED
TO BE LOWERED WITH THE DEEPER MOISTURE/SATURATION REMAINING EAST/
SOUTH OF THE FCST AREA. THUS LEFT MOST RAIN CHANCES FOR FRI NIGHT/
SAT AS IS FOR THIS CYCLE. TIGHTER SFC-850MB GRADIENT ON BACK SIDE OF
THE SFC-850MB LOW IS OVER THE AREA SAT. THIS WITH MDT TO STRONG LOW
LEVEL COLD ADVECTION AND 925MB WINDS INCREASING TO THE 35-40KT
RANGE. DEPENDING ON TIMING/ARRIVAL OF THE STRONGER GRADIENT/COLD
ADVECTION MAY YET NEED A WIND ADVISORY FOR PARTS OF THE AREA SAT.
HIGHS SAT LIKELY TO BE IN THE MORNING WITH STEADY/SLOWLY FALLING
TEMPS IN THE AFTERNOON. SOME INDICATIONS FOR SECONDARY SHORTWAVES TO
ROTATE SOUTH IN THE BACK SIDE OF THE TROUGH LATE SAT/SAT NIGHT...
ALONG WITH MOISTURE WRAPPING AROUND THE SFC-700MB LOW. WITH COLDER
AIR IN PLACE...PRECIP CHANCES IN THE 20-40 PERCENT RANGE FOR
RAIN/SNOW CHANGING TO SNOW SAT NIGHT REASONABLE FOR NOW.
FAVORING A MODEL/ENSEMBLE CONSENSUS...GENERALLY TRENDED LOWS/HIGHS
FOR TONIGHT THRU SAT NIGHT TOWARD A BLEND OF THE NUMERICAL
GUIDANCE.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
250 PM CST WED NOV 23 2011
23.00Z MEDIUM RANGE MODELS IN MODEST AGREEMENT WITH EACH OTHER AND
THEIR PREVIOUS RUNS SUN...BUT STILL PLENTY OF DETAIL DIFFERENCES IN
THE TROUGHING OVER THE EAST HALF OF THE CONUS. MODEST AGREEMENT
CONTINUES MON THE NEXT STRONGER SHORTWAVE TROUGH/ENERGY DROPS
INTO THE NORTHERN PLAINS. TREND IS SLOWER/FURTHER SOUTH WITH AN
UPPER LOW IN THE SOUTHEAST CONUS. MODELS DIVERGE CONSIDERABLY WITH
THE DETAILS BY TUE AND FOR WED...BUT A GENERAL CONSENSUS FOR
LONGWAVE TROUGHING OVER EASTERN NOAM AND LONGWAVE RIDGING ALONG THE
WEST COAST. NONE OF THE MODEL DISPLAYING CLEARLY BETTER RUN-TO-RUN
CONSISTENCY THAN THE OTHERS IN THE SUN-WED PERIOD. OF NOTE THOUGH
23.06Z GFS TRENDED CLOSER TO 23.00Z ECMWF THRU MUCH OF THE DAY 4-7
PERIOD WHILE 23.12Z GFS TRENDED MUCH MORE PROGRESSIVE WITH THE
SOUTHEAST CONUS SYSTEM MON/TUE. NEEDLESS TO SAY...LONG-TERM FCST
CONFIDENCE BELOW AVERAGE THIS CYCLE. WITH NO CLEAR MODEL FAVORITE OR
NO ONE MODEL SHOWING BETTER RUN-TO-RUN CONSISTENCY...PREFER THE
PMDEPD IDEA OF FAVORING A MODEL/ENSEMBLE BLEND FOR NOW. SOME
CONSENSUS FOR SHORTWAVE RIDGING AND HIGH PRESSURE TO BUILD OVER THE
AREA FOR SUN IN THE WAKE OF THE DEPARTING SAT SYSTEM...FOR A
COOL/DRY DAY SUNDAY. NEXT TROUGH/SHORT-WAVE MOVES ACROSS THE
NORTHERN PLAINS MON...BUT DIFFERENCES OF SPEED/STRENGTH APPEAR.
THESE DIFFERENCES...ESPECIALLY AT THE LOWER LEVELS...INCREASE FOR
TUE INTO WED. GFS WITH A SLOWER/ STRONGER SYSTEM ACROSS THE UPPER
MIDWEST/GREAT LAKES LATE MON-WED WITH ECMWF WEAKER/MORE PROGRESSIVE
SYSTEM. AGAIN LIKE PMDEPD IDEA...FCST GRIDS FOR MON-WED INCORPORATED
A STRONG MODEL/ENSEMBLE CONSENSUS/BLEND UNTIL CLEARER DETAILS/
SIGNALS ARE SEEN. OVERALL LONGWAVE TROUGHING IN THE EASTERN CONUS
AND RIDGING OVER WESTERN NOAM RESULTS IN NORTHWEST FLOW ALOFT OVER
THE NORTH-CENTRAL CONUS. TEMPERATURES FOR THE SUN-WED PERIOD LOOKING
TO BE CLOSER TO NORMAL.
&&
.AVIATION...TODAY AND TONIGHT
1115 AM CST WED NOV 23 2011
MVFR/IFR STRATUS DECK PERSISTS ACROSS THE REGION...PER LATEST
SATELLITE IMAGERY AND SFC OBS. RUC RH FIELDS AND BUFKIT SOUNDINGS
SUGGEST THIS MAY HOLD THROUGH THE EARLY/MID AFTERNOON HOURS...WITH
EROSION/LIFTING AS THE CLOUD DECK TRANSITIONS EAST LATER THIS
AFTERNOON. NAM12/RUC13 SOUNDINGS THEN SUGGEST THAT THIS NEAR SFC
SATURATION WOULD REESTABLISH ITSELF UNDER THE LOW LEVEL INVERSION
TONIGHT. MORE LOW STRATUS COULD DEVELOP AS A RESULT. HOWEVER...THE
SFC RIDGE AXIS SHIFTS EAST OVERNIGHT...ALLOWING FOR MORE STIRRING IN
THE VERTICAL AND SFC WINDS...UNLIKE THE LIGHTER WIND REGIME OF THIS
MORNING. SO...WILL LEAN TOWARD SKC-SCT FOR NOW. THIS POTENTIAL FOR
LOW STRATUS WILL HAVE TO BE MONITORED...HOWEVER...THROUGH THE
NIGHTTIME HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST WED NOV 23 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
222 PM CST WED NOV 23 2011
.SHORT TERM...FORECASTING CLOUD COVER IS THE BIGGEST CHALLENGE OF
TONIGHT AND TOMORROWS FORECAST...AS IT HAS BEEN FOR THE LAST FEW
DAYS. IT IS USUALLY WISE TO KEEP CLOUDS AROUND IN NOVEMBER AND
DECEMBER AND WILL KEEP MORE CLOUDS IN THE FORECAST THAN THE
GUIDANCE WOULD INDICATE. THE RUC HAD THE BEST FORECAST OF THE
CLOUD COVER THIS AFTERNOON WITH CLEARING OCCURING IN THE DOWNSLOPE
AREA OF NORTHEAST WISCONSIN. IT WOULD KEEP THE CURRENT CLOUDS IN
THE WESTERN PART OF THE FORECAST AREA FOR MOST OF THE NIGHT WITH
CLOUDS REFORMING GENERALLY NORTH OF GREEN BAY IN THE EAST.
DIFFICULT TO SAY FOR SURE. WE HAVE TRIED JUST ABOUT EVERY MODEL
FIELD (1000MB TO 925MB, 925MB, 925 TO 950MB RELATIVE HUMIDITY,
MOISTURE TRANSPORT VECTORS, AND HRR CEILING HEIGHTS) BUT NONE
DEPICT THE CURRENT CLOUDS THAT WELL. LOWS TONIGHT SHOULD BE ABOVE
NORMAL ONCE AGAIN DUE TO MILD BOUNDARY LAYER TEMPERATURES, A
STEADY BREEZE AND CLOUDS. THE COOLEST TEMPERATURES SHOULD BE IN
VALLEYS WITH CLEAR SKIES AND IN AREAS WITH SNOW ON THE GROUND.
THANKSGIVING MAY NOT BE QUITE AS MILD AS IT LOOKED LIKE A FEW
DAYS AGO AS THERE IS A POSSIBILITY THAT THE DAY COULD START OUT
WITH CLOUDS LIKE MOST OF THE LAST FEW DAYS. 925MB TEMPERATURES ARE
VERY MILD THOUGH, AND EVEN WITH CLOUDS IT WILL BE 10 TO 15 DEGREES
ABOVE NORMAL AND THERE SHOULD AT LEAST BE SOME SUNSHINE BY
AFTERNOON IN MOST PLACES.
.LONG TERM...THURSDAY NIGHT TO WEDNESDAY.
SOUTHERLY FLOW AHEAD OF A WEAK COLD FRONT EXPECTED THURSDAY
EVENING. GRADIENT EXPECTED TO SLACKEN DURING THE NIGHT...ESPECIALLY
ACROSS THE NORTH. DEPENDING ON HOW MUCH SNOW PACK IS LEFT...ENOUGH
EVIDENCE TO ADD FOG AFTER MIDNIGHT OVER THE FAR NORTH. MODELS TODAY
ARE SHOWING LOW LEVEL MOISTURE TRAPPED BELOW AN INVERSION LATER
THURSDAY NIGHT INTO FRIDAY. QUESTION IS HOW QUICK THIS LAYER WILL
SATURATE. DO THINK BEST SATURATION WILL OCCUR ACROSS THE NORTH. CONFIDENCE
IS NOT THAT GREAT ACROSS THE SOUTH DUE TO DIFFERING NUMERICAL
GUIDANCE VALUES FOR CLOUD HEIGHT. WITH EXPECTED LOW CLOUDS TO
DEVELOP ACROSS THE NORTH AND WEAK UPWARD VERTICAL MOTIONS...THOUGHTS
TURNED TO THE POTENTIAL FOR DRIZZLE LATE THURSDAY NIGHT INTO FRIDAY.
DO THINK MOISTURE WILL BE TOO SHALLOW THURSDAY NIGHT INTO FRIDAY MORNING...
BUT CLOUD LAYER MAY BE DEEP ENOUGH TO SUPPORT DRIZZLE FRIDAY AFTERNOON.
DID NOT ADD DRIZZLE TO THE FORECAST ACROSS THE NORTH ON FRIDAY AND
WILL PASS ON MY CONCERNS TO MIDNIGHT SHIFT.
FOR FRIDAY NIGHT...MOIST SOUTHERLY FLOW EXPECTED ACROSS THE AREA. THINK
PRECIPITATION WILL START OUT AS DRIZZLE WITH A MORE STEADIER RAIN LATE
FRIDAY NIGHT INTO SATURDAY AS FRONT APPROACHES. PRECIPITATION WILL
CONTINUE INTO SATURDAY. MORE QUESTIONS APPEAR ON SATURDAY AS SEVERAL
MODELS SHOW A DRY SLOT MOVING ACROSS THE REGION SATURDAY AFTERNOON
INTO SATURDAY NIGHT. DESPITE A FEW MODELS DRYING US OUT FOR AWHILE...
WILL CONTINUE A CHANCE OF RAIN SATURDAY AFTERNOON AND RAIN OR SNOW
SATURDAY NIGHT. MANY QUESTIONS LINGER SATURDAY NIGHT ON HOW FAST THE
COLD AIR WILL ARRIVE. LATER SHIFTS WILL PROBABLY NEED TO ALTER TIMING
THE CHANGEOVER TO ALL SNOW ACROSS SOME PORTION OF THE FORECAST AREA.
OTHERWISE...ANOTHER SYSTEM WILL MOVE ACROSS THE AREA MONDAY NIGHT
AND TUESDAY AND WILL BRING ANOTHER SMALL CHANCE FOR RAIN OR SNOW
TO THE AREA.
&&
.AVIATION...IFR/MVFR CIGS EXPECTED FOR MUCH OF THE NIGHT AT
ISW/CWA/STE/AIG/RRL/RRL/ARV/EGV. CLOUDS MAY CLEAR TO SOME EXTENT
AT GRB/ATW/OSH/SUE/PCZ/Y50/MTW THIS EVENING AND THEN REFORM LATE
TONIGHT. VERY TRICKY CLOUD FORECAST.
WHERE SKIES ARE CLEAR THERE WILL LIKELY BE FROST ON AIRCRAFT
PARKED ON THE RAMP. LOW LEVEL WIND SHEAR POSSIBLE TONIGHT WITH
SOUTHWEST WINDS AROUND 35 KNOTS AT 1000` AGL AND SURFACE WINDS
FROM THE SOUTH AT 5 TO 10 KNOTS.
&&
.MARINE...HAZARDOUS CONDITIONS WITH GALE FORCE ARE POSSIBLE OVER
THE UPCOMING WEEKEND. MODEL DIFFERENCES IN STRENGTH AND TIMING OF
THIS SYSTEM THIS WEEKEND ARE MITIGATING FACTORS IN INTRODUCING
GALES IN THE HAZARDOUS WEATHER OUTLOOK. IT APPEARS THAT THE
STRONGEST WINDS WILL BE SATURDAY NIGHT INTO SUNDAY...BUT COULD
START SATURDAY AFTERNOON IF THE QUICKER MODEL SOLUTION IS CORRECT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
RDM/ECKBERG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1115 AM CST WED NOV 23 2011
.SHORT TERM...TODAY THROUGH FRIDAY
346 AM CST WED NOV 23 2011
AT 3 AM...WE ARE CONTINUING TO WATCH A BAND OF LOW CLOUDS MOVING
EAST ACROSS THE FORECAST AREA. THIS HAS BEEN SHOWING UP WELL IN
THE FOG /11-3.9 MICRON/ CHANNEL OF THE SATELLITE LOOP. HOWEVER
DURING THE PAST TWO HOURS...THE WESTERN EXTENT OF THESE LOW CLOUDS
HAS BEEN BECOMING LESS DISCERNIBLE AS HIGHER CLOUDS ASSOCIATED
WITH THE 700-500 MB TROUGH MOVES OVER THEM. THE 23.00Z NAM/WRF AND
23.05Z RUC CONTINUE TO SHOW THAT THESE CLOUDS WILL LINGER ACROSS
MUCH OF THE FORECAST AREA THIS MORNING...AND THEN GRADUALLY MOVE
EAST OUT OF THE AREA THIS AFTERNOON. AS A RESULT...WENT WITH A
MOSTLY CLOUDY MORNING...AND DECREASING CLOUDS FOR THIS AFTERNOON.
AS A VERY WARM AIR MASS MOVES INTO THE REGION FROM THIS AFTERNOON
INTO THANKSGIVING...BUFKIT SOUNDINGS CONTINUE TO SUGGEST THAT
MUCH OF THIS WARMING WILL TAKE PLACE ALOFT. THIS WILL END UP
SETTING UP A VERY STRONG INVERSION WHICH WILL GREATLY LIMIT HOW
DEEP THAT THE AREA WILL BE ABLE TO MIX FOR BOTH THANKSGIVING AND
FRIDAY. AT THIS TIME...IT LOOKS LIKE MIXING WILL ONLY EXTEND UP TO
950 MB AT BEST. MIXING THESE TEMPERATURES DOWN TO THE
SURFACE...ONLY RESULTS IN AFTERNOON HIGH TEMPERATURES RANGING FROM
THE MID 40S TO MID 50S. THEREFORE WE MAY HAVE TO RELY ON WARM
SURFACE AIR BEING ADVECTED INTO THE REGION TO REACH ANYWHERE NEAR
60 DEGREES. THEREFORE CONCERNED THAT THE MODELS MAYBE OVERDOING
SOME OF THE HIGH TEMPERATURES. THIS IS ESPECIALLY THE CASE ON
THANKSGIVING DUE TO THE LIGHTER WINDS.
ON THURSDAY NIGHT...THE ECMWF CONTINUES TO BE ABOUT 5 DEGREES
WARMER THAN THE ALL BLEND. THE ECMWF IS A BIT MORE BELIEVABLE IN
THIS SYNOPTIC REGIME /SOUTHERLY WINDS AHEAD OF AN APPROACHING
TROUGH/. AS A RESULT...RAISED THE MINIMUM TEMPERATURES A FEW MORE
DEGREES. THIS WAS ALSO DONE TO FRIDAY NIGHT TOO.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
346 AM CST WED NOV 23 2011
THE 23.00Z MODELS CONTINUE TO BE IN FRAILLY GOOD AGREEMENT THAT A
LONG WAVE TROUGH WILL MOVE EAST ACROSS THE FORECAST AREA ON
SATURDAY NIGHT. THERE CONTINUES TO BE TWO STRONG SHORT WAVE
TROUGHS EMBEDDED IN THIS TROUGH. THE FIRST OF THESE SYSTEMS IS
EXPECTED TO MOVE EAST ACROSS THE NORTHERN PORTIONS OF PRAIRIE
PROVIDENCES OF CANADA /SASKATCHEWAN AND MANITOBA/. MEANWHILE THE
OTHER SHORT WAVE TROUGH WILL BE MOVING EAST ACROSS CENTRAL
PLAINS...AND THE MID AND UPPER MISSISSIPPI RIVER VALLEYS. A
SURFACE COLD FRONT ASSOCIATED WITH THE LATTER OF THE TWO SHORT
WAVE TROUGHS WILL MOVE THROUGH THE AREA ON SATURDAY. AT THIS
TIME...THE BEST MOISTURE TRANSPORT AND ISENTROPIC LIFT WILL AFFECT
THE AREA ON FRIDAY NIGHT AND EARLY SATURDAY MORNING. WITH THIS
SAID...THERE ARE STILL SOME SUBTLE DIFFERENCES ON WHEN AND WHERE
THE PRECIPITATION WILL DEVELOP ACROSS THE AREA. AS RESULT...JUST
KEPT THE PRECIPITATION CHANCES IN THE LIKELY /55 TO 64 PERCENT/
RANGE FOR FRIDAY NIGHT. THE PRECIPITATION CHANCES THEN GRADUALLY
LOWER FROM SATURDAY THROUGH SUNDAY AS THE SYSTEM MOVES EAST OUT OF
THE AREA.
IN THE WAKE OF THIS FRONT...TEMPERATURES WILL COOL ENOUGH ALOFT FOR
THE PRECIPITATION TO GRADUALLY CHANGE OVER TO LIGHT SNOW ON
SATURDAY NIGHT /MAYBE LATE SATURDAY AFTERNOON ACROSS NORTHEAST
IOWA AND SOUTHEAST MINNESOTA/...AND THEN POSSIBLY BACK TO RAIN ON
SUNDAY AS THE BOUNDARY LAYER WARMS. WITH THE PRECIPITATION SO
LIGHT AND THE GROUND STILL WARM...NOT EXPECTING TOO MUCH SNOW
ACCUMULATIONS WITH THIS SYSTEM.
FOR EARLY NEXT WEEK...THE MODELS CONTINUE TO STRUGGLE AS THE
OPERATIONAL RUNS OF BOTH THE GFS AND ECMWF HAVE BEEN GOING BACK
AND FORTH ON WHETHER A CLOSED LOW WILL DEVELOP SOMEWHERE IN THE
EASTERN CONUS. MUCH OF THIS IS A RESULT OF THE MODELS TRYING TO
DEVELOP A BLOCKING RIDGE OVER THE WESTERN ATLANTIC. LOOKING AT THE
PROGRESSIVE AND RATHER ACTIVE WAVE PATTERN THAT EXISTS FROM
NORTHERN AFRICA EAST INTO THE EASTERN PACIFIC...IT DOES NOT MAKE
THAT MUCH SENSE THAT THERE WOULD BE SO MUCH BLOCKINESS ACROSS THE
WESTERN ATLANTIC. IN THIS TYPE OF FLOW PATTERN...SYSTEMS ARE USUALLY
RATHER TRANSITORY. WONDERING IF THE FLOW PATTERN IS SO ACTIVE THAT
THE MODELS ARE HAVING A HARD TIME DEALING WITH SO MANY WAVES IN
THE FLOW PATTERN...AND THIS IS LEADING TO PART OF THE RUN-TO-RUN
INCONSISTENCIES IN THE MODELS DURING THE PAST WEEK.
IF THIS WAS NOT ENOUGH OF A PROBLEM...WE MAY IN STORE EVEN LESS
CERTAINTY IN THE EXTENDED MODELS IN THE 8 TO 14 DAY TIME PERIOD.
THE REASON FOR THIS IS THERE CONTINUES TO BE VERY GOOD CONSENSUS
IN THE GLOBAL /BRAZILIAN...CANADIAN...ECMWF... JAPANESE...AND
U.S./ MODELS THAT THE MADDEN JULIAN OSCILLATION /MJO/ WHICH IS
LOCATED IN THE INDIAN OCEAN WILL RAPIDLY INTENSIFY DURING THIS
TIME PERIOD. SINCE THE MODELS USUALLY STRUGGLE INITIALLY IN THESE
PATTERNS...MODEL RUN-TO-RUN CONSISTENCY MAY BE FAR LESS THAN
DESIRED. IT IS INTERESTING TO NOTE THAT CATEGORY 2 HURRICANE
KENNETH IN THE EASTERN PACIFIC IS LOCATED IN AN AREA OF FAVORED
DEVELOPMENT WHEN THE MJO IS LOCATED IN ITS CURRENT POSITION.
&&
.AVIATION...
1115 AM CST WED NOV 23 2011
MVFR/IFR STRATUS DECK PERSISTS ACROSS THE REGION...PER LATEST
SATELLITE IMAGERY AND SFC OBS. RUC RH FIELDS AND BUFKIT SOUNDINGS
SUGGEST THIS MAY HOLD THROUGH THE EARLY/MID AFTERNOON HOURS...WITH
EROSION/LIFTING AS THE CLOUD DECK TRANSITIONS EAST LATER THIS
AFTERNOON. NAM12/RUC13 SOUNDINGS THEN SUGGEST THAT THIS NEAR SFC
SATURATION WOULD REESTABLISH ITSELF UNDER THE LOW LEVEL INVERSION
TONIGHT. MORE LOW STRATUS COULD DEVELOP AS A RESULT. HOWEVER...THE
SFC RIDGE AXIS SHIFTS EAST OVERNIGHT...ALLOWING FOR MORE STIRRING IN
THE VERTICAL AND SFC WINDS...UNLIKE THE LIGHTER WIND REGIME OF THIS
MORNING. SO...WILL LEAN TOWARD SKC-SCT FOR NOW. THIS POTENTIAL FOR
LOW STRATUS WILL HAVE TO BE MONITORED...HOWEVER...THROUGH THE
NIGHTTIME HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
242 AM CST WED NOV 23 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... BOYNE
LONG TERM.... BOYNE
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
535 AM CST WED NOV 23 2011
.SHORT TERM...TODAY THROUGH FRIDAY
346 AM CST WED NOV 23 2011
AT 3 AM...WE ARE CONTINUING TO WATCH A BAND OF LOW CLOUDS MOVING
EAST ACROSS THE FORECAST AREA. THIS HAS BEEN SHOWING UP WELL IN
THE FOG /11-3.9 MICRON/ CHANNEL OF THE SATELLITE LOOP. HOWEVER
DURING THE PAST TWO HOURS...THE WESTERN EXTENT OF THESE LOW CLOUDS
HAS BEEN BECOMING LESS DISCERNIBLE AS HIGHER CLOUDS ASSOCIATED
WITH THE 700-500 MB TROUGH MOVES OVER THEM. THE 23.00Z NAM/WRF AND
23.05Z RUC CONTINUE TO SHOW THAT THESE CLOUDS WILL LINGER ACROSS
MUCH OF THE FORECAST AREA THIS MORNING...AND THEN GRADUALLY MOVE
EAST OUT OF THE AREA THIS AFTERNOON. AS A RESULT...WENT WITH A
MOSTLY CLOUDY MORNING...AND DECREASING CLOUDS FOR THIS AFTERNOON.
AS A VERY WARM AIR MASS MOVES INTO THE REGION FROM THIS AFTERNOON
INTO THANKSGIVING...BUFKIT SOUNDINGS CONTINUE TO SUGGEST THAT
MUCH OF THIS WARMING WILL TAKE PLACE ALOFT. THIS WILL END UP
SETTING UP A VERY STRONG INVERSION WHICH WILL GREATLY LIMIT HOW
DEEP THAT THE AREA WILL BE ABLE TO MIX FOR BOTH THANKSGIVING AND
FRIDAY. AT THIS TIME...IT LOOKS LIKE MIXING WILL ONLY EXTEND UP TO
950 MB AT BEST. MIXING THESE TEMPERATURES DOWN TO THE
SURFACE...ONLY RESULTS IN AFTERNOON HIGH TEMPERATURES RANGING FROM
THE MID 40S TO MID 50S. THEREFORE WE MAY HAVE TO RELY ON WARM
SURFACE AIR BEING ADVECTED INTO THE REGION TO REACH ANYWHERE NEAR
60 DEGREES. THEREFORE CONCERNED THAT THE MODELS MAYBE OVERDOING
SOME OF THE HIGH TEMPERATURES. THIS IS ESPECIALLY THE CASE ON
THANKSGIVING DUE TO THE LIGHTER WINDS.
ON THURSDAY NIGHT...THE ECMWF CONTINUES TO BE ABOUT 5 DEGREES
WARMER THAN THE ALL BLEND. THE ECMWF IS A BIT MORE BELIEVABLE IN
THIS SYNOPTIC REGIME /SOUTHERLY WINDS AHEAD OF AN APPROACHING
TROUGH/. AS A RESULT...RAISED THE MINIMUM TEMPERATURES A FEW MORE
DEGREES. THIS WAS ALSO DONE TO FRIDAY NIGHT TOO.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
346 AM CST WED NOV 23 2011
THE 23.00Z MODELS CONTINUE TO BE IN FRAILLY GOOD AGREEMENT THAT A
LONG WAVE TROUGH WILL MOVE EAST ACROSS THE FORECAST AREA ON
SATURDAY NIGHT. THERE CONTINUES TO BE TWO STRONG SHORT WAVE
TROUGHS EMBEDDED IN THIS TROUGH. THE FIRST OF THESE SYSTEMS IS
EXPECTED TO MOVE EAST ACROSS THE NORTHERN PORTIONS OF PRAIRIE
PROVIDENCES OF CANADA /SASKATCHEWAN AND MANITOBA/. MEANWHILE THE
OTHER SHORT WAVE TROUGH WILL BE MOVING EAST ACROSS CENTRAL
PLAINS...AND THE MID AND UPPER MISSISSIPPI RIVER VALLEYS. A
SURFACE COLD FRONT ASSOCIATED WITH THE LATTER OF THE TWO SHORT
WAVE TROUGHS WILL MOVE THROUGH THE AREA ON SATURDAY. AT THIS
TIME...THE BEST MOISTURE TRANSPORT AND ISENTROPIC LIFT WILL AFFECT
THE AREA ON FRIDAY NIGHT AND EARLY SATURDAY MORNING. WITH THIS
SAID...THERE ARE STILL SOME SUBTLE DIFFERENCES ON WHEN AND WHERE
THE PRECIPITATION WILL DEVELOP ACROSS THE AREA. AS RESULT...JUST
KEPT THE PRECIPITATION CHANCES IN THE LIKELY /55 TO 64 PERCENT/
RANGE FOR FRIDAY NIGHT. THE PRECIPITATION CHANCES THEN GRADUALLY
LOWER FROM SATURDAY THROUGH SUNDAY AS THE SYSTEM MOVES EAST OUT OF
THE AREA.
IN THE WAKE OF THIS FRONT...TEMPERATURES WILL COOL ENOUGH ALOFT FOR
THE PRECIPITATION TO GRADUALLY CHANGE OVER TO LIGHT SNOW ON
SATURDAY NIGHT /MAYBE LATE SATURDAY AFTERNOON ACROSS NORTHEAST
IOWA AND SOUTHEAST MINNESOTA/...AND THEN POSSIBLY BACK TO RAIN ON
SUNDAY AS THE BOUNDARY LAYER WARMS. WITH THE PRECIPITATION SO
LIGHT AND THE GROUND STILL WARM...NOT EXPECTING TOO MUCH SNOW
ACCUMULATIONS WITH THIS SYSTEM.
FOR EARLY NEXT WEEK...THE MODELS CONTINUE TO STRUGGLE AS THE
OPERATIONAL RUNS OF BOTH THE GFS AND ECMWF HAVE BEEN GOING BACK
AND FORTH ON WHETHER A CLOSED LOW WILL DEVELOP SOMEWHERE IN THE
EASTERN CONUS. MUCH OF THIS IS A RESULT OF THE MODELS TRYING TO
DEVELOP A BLOCKING RIDGE OVER THE WESTERN ATLANTIC. LOOKING AT THE
PROGRESSIVE AND RATHER ACTIVE WAVE PATTERN THAT EXISTS FROM
NORTHERN AFRICA EAST INTO THE EASTERN PACIFIC...IT DOES NOT MAKE
THAT MUCH SENSE THAT THERE WOULD BE SO MUCH BLOCKINESS ACROSS THE
WESTERN ATLANTIC. IN THIS TYPE OF FLOW PATTERN...SYSTEMS ARE USUALLY
RATHER TRANSITORY. WONDERING IF THE FLOW PATTERN IS SO ACTIVE THAT
THE MODELS ARE HAVING A HARD TIME DEALING WITH SO MANY WAVES IN
THE FLOW PATTERN...AND THIS IS LEADING TO PART OF THE RUN-TO-RUN
INCONSISTENCIES IN THE MODELS DURING THE PAST WEEK.
IF THIS WAS NOT ENOUGH OF A PROBLEM...WE MAY IN STORE EVEN LESS
CERTAINTY IN THE EXTENDED MODELS IN THE 8 TO 14 DAY TIME PERIOD.
THE REASON FOR THIS IS THERE CONTINUES TO BE VERY GOOD CONSENSUS
IN THE GLOBAL /BRAZILIAN...CANADIAN...ECMWF... JAPANESE...AND
U.S./ MODELS THAT THE MADDEN JULIAN OSCILLATION /MJO/ WHICH IS
LOCATED IN THE INDIAN OCEAN WILL RAPIDLY INTENSIFY DURING THIS
TIME PERIOD. SINCE THE MODELS USUALLY STRUGGLE INITIALLY IN THESE
PATTERNS...MODEL RUN-TO-RUN CONSISTENCY MAY BE FAR LESS THAN
DESIRED. IT IS INTERESTING TO NOTE THAT CATEGORY 2 HURRICANE
KENNETH IN THE EASTERN PACIFIC IS LOCATED IN AN AREA OF FAVORED
DEVELOPMENT WHEN THE MJO IS LOCATED IN ITS CURRENT POSITION.
&&
.AVIATION...TODAY AND TONIGHT
535 AM CST WED NOV 23 2011
IR SATELLITE THIS MORNING SHOWS A LARGE AREA OF STRATUS CLOUDS
FROM NORTHEAST MINNESOTA/NORTHWEST WISCONSIN SOUTH INTO MISSOURI.
CEILINGS IN THIS DECK ARE PRIMARILY MVFR WITH SOME OCCASIONAL MVFR
VISIBILITIES IN FOG AS WELL. THE 23.06Z NAM AND 23.09Z RUC SEEM TO
HAVE A DECENT HANDLE ON THE LOW LEVEL MOISTURE FIELD AND SUGGEST
THESE CLOUDS WILL HANG ON THROUGH THE MORNING HOURS. BOTH MODELS
SUGGEST KRST SHOULD BREAK OUT FIRST AND WILL GIVE A TIMING OF THIS
OCCURRING AROUND 18Z. KLSE WILL BE A LITTLE SLOWER AND WILL SHOW
THIS HAPPENING AT 20Z. THE RELATIVE HUMIDITY PROGS FROM THE NAM
SUGGEST GOOD DRYING WILL OCCUR THEN THROUGH THE REMAINDER OF THE
DAY INTO THE EVENING BUT LOOKING AT THE BUFKIT SOUNDINGS...THE
TEMP/DEW POINT PROFILE STAY WITHIN A COUPLE DEGREES OF EACH OTHER
WHERE THE MOISTURE IS CURRENTLY PRESENT. AS TEMPERATURES COOL THIS
EVENING...BOTH THE NAM AND RUC SUGGEST SATURATION WILL OCCUR AGAIN
WITH ANOTHER STRATUS DECK UNDER THE INVERSION. NOT SEEING ANY
INDICATIONS OF THIS OCCURRING TONIGHT OUT ACROSS WESTERN MINNESOTA
WHERE THE STRATUS DECK WAS LAST NIGHT...SO FOR NOW...WILL NOT
INCLUDE THIS IN THE FORECASTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
242 AM CST WED NOV 23 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
347 AM CST WED NOV 23 2011
.SHORT TERM...TODAY THROUGH FRIDAY
346 AM CST WED NOV 23 2011
AT 3 AM...WE ARE CONTINUING TO WATCH A BAND OF LOW CLOUDS MOVING
EAST ACROSS THE FORECAST AREA. THIS HAS BEEN SHOWING UP WELL IN
THE FOG /11-3.9 MICRON/ CHANNEL OF THE SATELLITE LOOP. HOWEVER
DURING THE PAST TWO HOURS...THE WESTERN EXTENT OF THESE LOW CLOUDS
HAS BEEN BECOMING LESS DISCERNIBLE AS HIGHER CLOUDS ASSOCIATED
WITH THE 700-500 MB TROUGH MOVES OVER THEM. THE 23.00Z NAM/WRF AND
23.05Z RUC CONTINUE TO SHOW THAT THESE CLOUDS WILL LINGER ACROSS
MUCH OF THE FORECAST AREA THIS MORNING...AND THEN GRADUALLY MOVE
EAST OUT OF THE AREA THIS AFTERNOON. AS A RESULT...WENT WITH A
MOSTLY CLOUDY MORNING...AND DECREASING CLOUDS FOR THIS AFTERNOON.
AS A VERY WARM AIR MASS MOVES INTO THE REGION FROM THIS AFTERNOON
INTO THANKSGIVING...BUFKIT SOUNDINGS CONTINUE TO SUGGEST THAT
MUCH OF THIS WARMING WILL TAKE PLACE ALOFT. THIS WILL END UP
SETTING UP A VERY STRONG INVERSION WHICH WILL GREATLY LIMIT HOW
DEEP THAT THE AREA WILL BE ABLE TO MIX FOR BOTH THANKSGIVING AND
FRIDAY. AT THIS TIME...IT LOOKS LIKE MIXING WILL ONLY EXTEND UP TO
950 MB AT BEST. MIXING THESE TEMPERATURES DOWN TO THE
SURFACE...ONLY RESULTS IN AFTERNOON HIGH TEMPERATURES RANGING FROM
THE MID 40S TO MID 50S. THEREFORE WE MAY HAVE TO RELY ON WARM
SURFACE AIR BEING ADVECTED INTO THE REGION TO REACH ANYWHERE NEAR
60 DEGREES. THEREFORE CONCERNED THAT THE MODELS MAYBE OVERDOING
SOME OF THE HIGH TEMPERATURES. THIS IS ESPECIALLY THE CASE ON
THANKSGIVING DUE TO THE LIGHTER WINDS.
ON THURSDAY NIGHT...THE ECMWF CONTINUES TO BE ABOUT 5 DEGREES
WARMER THAN THE ALL BLEND. THE ECMWF IS A BIT MORE BELIEVABLE IN
THIS SYNOPTIC REGIME /SOUTHERLY WINDS AHEAD OF AN APPROACHING
TROUGH/. AS A RESULT...RAISED THE MINIMUM TEMPERATURES A FEW MORE
DEGREES. THIS WAS ALSO DONE TO FRIDAY NIGHT TOO.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
346 AM CST WED NOV 23 2011
THE 23.00Z MODELS CONTINUE TO BE IN FRAILLY GOOD AGREEMENT THAT A
LONG WAVE TROUGH WILL MOVE EAST ACROSS THE FORECAST AREA ON
SATURDAY NIGHT. THERE CONTINUES TO BE TWO STRONG SHORT WAVE
TROUGHS EMBEDDED IN THIS TROUGH. THE FIRST OF THESE SYSTEMS IS
EXPECTED TO MOVE EAST ACROSS THE NORTHERN PORTIONS OF PRAIRIE
PROVIDENCES OF CANADA /SASKATCHEWAN AND MANITOBA/. MEANWHILE THE
OTHER SHORT WAVE TROUGH WILL BE MOVING EAST ACROSS CENTRAL
PLAINS...AND THE MID AND UPPER MISSISSIPPI RIVER VALLEYS. A
SURFACE COLD FRONT ASSOCIATED WITH THE LATTER OF THE TWO SHORT
WAVE TROUGHS WILL MOVE THROUGH THE AREA ON SATURDAY. AT THIS
TIME...THE BEST MOISTURE TRANSPORT AND ISENTROPIC LIFT WILL AFFECT
THE AREA ON FRIDAY NIGHT AND EARLY SATURDAY MORNING. WITH THIS
SAID...THERE ARE STILL SOME SUBTLE DIFFERENCES ON WHEN AND WHERE
THE PRECIPITATION WILL DEVELOP ACROSS THE AREA. AS RESULT...JUST
KEPT THE PRECIPITATION CHANCES IN THE LIKELY /55 TO 64 PERCENT/
RANGE FOR FRIDAY NIGHT. THE PRECIPITATION CHANCES THEN GRADUALLY
LOWER FROM SATURDAY THROUGH SUNDAY AS THE SYSTEM MOVES EAST OUT OF
THE AREA.
IN THE WAKE OF THIS FRONT...TEMPERATURES WILL COOL ENOUGH ALOFT FOR
THE PRECIPITATION TO GRADUALLY CHANGE OVER TO LIGHT SNOW ON
SATURDAY NIGHT /MAYBE LATE SATURDAY AFTERNOON ACROSS NORTHEAST
IOWA AND SOUTHEAST MINNESOTA/...AND THEN POSSIBLY BACK TO RAIN ON
SUNDAY AS THE BOUNDARY LAYER WARMS. WITH THE PRECIPITATION SO
LIGHT AND THE GROUND STILL WARM...NOT EXPECTING TOO MUCH SNOW
ACCUMULATIONS WITH THIS SYSTEM.
FOR EARLY NEXT WEEK...THE MODELS CONTINUE TO STRUGGLE AS THE
OPERATIONAL RUNS OF BOTH THE GFS AND ECMWF HAVE BEEN GOING BACK
AND FORTH ON WHETHER A CLOSED LOW WILL DEVELOP SOMEWHERE IN THE
EASTERN CONUS. MUCH OF THIS IS A RESULT OF THE MODELS TRYING TO
DEVELOP A BLOCKING RIDGE OVER THE WESTERN ATLANTIC. LOOKING AT THE
PROGRESSIVE AND RATHER ACTIVE WAVE PATTERN THAT EXISTS FROM
NORTHERN AFRICA EAST INTO THE EASTERN PACIFIC...IT DOES NOT MAKE
THAT MUCH SENSE THAT THERE WOULD BE SO MUCH BLOCKINESS ACROSS THE
WESTERN ATLANTIC. IN THIS TYPE OF FLOW PATTERN...SYSTEMS ARE USUALLY
RATHER TRANSITORY. WONDERING IF THE FLOW PATTERN IS SO ACTIVE THAT
THE MODELS ARE HAVING A HARD TIME DEALING WITH SO MANY WAVES IN
THE FLOW PATTERN...AND THIS IS LEADING TO PART OF THE RUN-TO-RUN
INCONSISTENCIES IN THE MODELS DURING THE PAST WEEK.
IF THIS WAS NOT ENOUGH OF A PROBLEM...WE MAY IN STORE EVEN LESS
CERTAINTY IN THE EXTENDED MODELS IN THE 8 TO 14 DAY TIME PERIOD.
THE REASON FOR THIS IS THERE CONTINUES TO BE VERY GOOD CONSENSUS
IN THE GLOBAL /BRAZILIAN...CANADIAN...ECMWF... JAPANESE...AND
U.S./ MODELS THAT THE MADDEN JULIAN OSCILLATION /MJO/ WHICH IS
LOCATED IN THE INDIAN OCEAN WILL RAPIDLY INTENSIFY DURING THIS
TIME PERIOD. SINCE THE MODELS USUALLY STRUGGLE INITIALLY IN THESE
PATTERNS...MODEL RUN-TO-RUN CONSISTENCY MAY BE FAR LESS THAN
DESIRED. IT IS INTERESTING TO NOTE THAT CATEGORY 2 HURRICANE
KENNETH IN THE EASTERN PACIFIC IS LOCATED IN AN AREA OF FAVORED
DEVELOPMENT WHEN THE MJO IS LOCATED IN ITS CURRENT POSITION.
&&
.AVIATION...THROUGH 06Z THURSDAY
1135 PM CST TUE NOV 22 2011
BIGGEST QUESTION CONTINUES TO BE CEILING HEIGHTS AND VISIBILITIES
THROUGH 18Z WEDNESDAY. STRATUS HAD MOVED BACK OVER THE TAF SITES
THIS EVENING. MODEL TRENDS IN BOTH THE 23.00Z NAM AND 23.02Z RUC
SHOW LOW LEVEL SATURATION TO CONTINUE WITH A STEADY DECREASE IN
CEILING HEIGHTS THROUGHOUT THE NIGHT. SOUNDINGS SUGGEST CEILINGS
TO LOWER INTO THE IFR CATEGORY AT KRST...BUT REMAIN IN THE LOWER
MVFR CATEGORY AT KLSE. LOWEST CEILINGS LOOK TO BE FROM 06Z-15Z
WEDNESDAY. WITH THE STRATUS FILLING BACK IN...VISIBILITIES SHOULD
REMAIN IN THE 2SM-4SM RANGE AT BOTH SITES. LATEST MODELS DO
INDICATE THE LOW LEVEL MOISTURE TO REMAIN TRAPPED UNDER THE
INVERSION ON WEDNESDAY. HOWEVER...THIS MOISTURE DOES THIN OUT AS
925MB WINDS BECOME MORE SOUTHWESTERLY. DID BACK UP THE CLEARING
TREND IN THE 06Z TAFS WITH CLOUDS SCATTERING OUT AROUND 17Z AT
KRST AND 20Z AT KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
242 AM CST WED NOV 23 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 PM CST TUE NOV 22 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY
219 PM CST TUE NOV 22 2011
MUCH OF THE FOCUS OVER THE SHORT TERM IS ON WHEN THE CLOUDS WILL GO
AWAY AND THE CONDITIONS FOR THANKSGIVING AND THE TRAVEL DAYS
AROUND IT.
A DEPARTING POSITIVELY TILTED MID LEVEL TROUGH EXTENDING FROM THE
SOUTHWESTERN GREAT LAKES DOWN TO THE LOWER MISSISSIPPI RIVER VALLEY
WILL QUICKLY MOVE TO THE EAST TONIGHT WITH BROAD RIDGING ALOFT
MOVING IN BEHIND THIS FEATURE. A WEAK MID LEVEL SHORT WAVE TROUGH
WILL PROPAGATE AROUND THE NORTHERN PERIPHERY OF THE RIDGE TONIGHT
INTO TOMORROW MORNING BUT SHOULD NOT HAVE MUCH OF AN IMPACT OUTSIDE
OF ADDING SOME HIGH LEVEL CLOUDS INTO THE MIX. DOWN AT THE
SURFACE...A LOW CENTERED OVER THE OHIO RIVER VALLEY WILL TRACK
NORTHEAST THROUGH THE EASTERN GREAT LAKES AS A RIDGE OF HIGH
PRESSURE EXTENDS FROM SOUTHERN ONTARIO THROUGH THE UPPER MISSISSIPPI
RIVER VALLEY REGION.
CLOUD COVER WILL REMAIN PROBLEMATIC THROUGH TOMORROW WITH A THIN
LAYER OF MOISTURE TRAPPED UNDER A SHALLOW INVERSION PER 22.12Z
REGIONAL RAOBS AND RUC SOUNDINGS. THIS THIN LATER OF STRATUS
EXTENDS FROM THE GREAT LAKES BACK INTO EASTERN NORTH DAKOTA AND
NEBRASKA...BUT HAS DEVELOPED AN ELONGATED HOLE THAT RUNS FROM
NORTHEAST WISCONSIN WEST SOUTHWEST THROUGH LA CROSSE TOWARD
CENTRAL IOWA. THE 22.18Z RUC...ALONG WITH PREVIOUS RUNS...HAVE
PICKED UP ON THIS DRY SLOT AND BASICALLY KEEPS IT IN PLACE THROUGH
TONIGHT. THE BACK EDGE TO THE WESTERN SIDE OF THE STRATUS APPEARS
TIED TO THE LOW LEVEL WARM FRONT WHICH IS EXPECTED TO COME THROUGH
THE REGION TOMORROW MORNING. EVEN IF THE CLEAR SLOT REMAINS IN
PLACE TONIGHT...THIS AREA MAY FOG UP QUICKLY GIVEN IDEAL
RADIATIONAL COOLING CONDITIONS WITH LIGHT WINDS AND THE RIDGE
OVERHEAD. SO...CONFIDENCE IS NOT HIGH ON WHEN THE CLOUDS WILL
COMPLETELY CLEAR OUT...BUT THE BETTER CHANCES APPEAR TO BE AROUND
LUNCHTIME TOMORROW WITH THE DRIER AND WARMER WESTERLIES COMING IN.
BEYOND THIS...EVERYTHING STILL LOOKS ON TAP FOR A WARM UP GOING
INTO THANKSGIVING WITH NEARLY IDEAL TRAVEL CONDITIONS OUTSIDE OF
SOME GUSTY WINDS ON THURSDAY. THE SURFACE PRESSURE GRADIENT
TIGHTENS UP ON THANKSGIVING AHEAD OF THE NEXT SYSTEM TRACKING
THROUGH THE ROCKIES WITH 22.12Z NAM AND GFS BUFKIT SOUNDINGS
SHOWING A SHALLOW MIXED LAYER UNDER THE STEEP 900MB INVERSION.
MOMENTUM TRANSFER FROM THESE SOUNDINGS SHOW THAT GUSTS WILL LIKELY
GO UP TO AROUND 20-25KT LATE THURSDAY MORNING INTO THE EARLY
AFTERNOON. TEMPERATURES ARE EXPECTED TO CLIMB INTO THE UPPER 50S
TO NEAR 60 IN SOME SPOTS WITH 22.12Z NAM AND GFS 850MB TEMPERATURE
ANOMALIES BETWEEN 1 TO 2 STANDARD DEVIATIONS. WHILE RECORD HIGH
TEMPERATURES ARE NOT EXPECTED...IT WILL DEFINITELY BE WELL ABOVE
NORMAL.
AS THE FRONT AND SURFACE LOW APPROACH ON FRIDAY...LOW LEVEL
MOISTURE TRANSPORT WILL BE ON THE INCREASE THOUGH DEEP MOISTURE
WILL BE SOMEWHAT LACKING INTO THE AFTERNOON. 22.12Z NAM AND GFS
SOUNDINGS SHOW A DEEP DRY LAYER THAT THE MOISTURE AND FORCING WILL
HAVE TO OVERCOME...WHICH MAY BE TOUGH DURING THE DAY FRIDAY. HAVE
LEFT SOME SLIGHT CHANCE PROBABILITIES FOR NOW FRIDAY
AFTERNOON...BUT HAVE TRIMMED THEM BACK TO MAINLY BEING IN
NORTHEAST IOWA.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
219 PM CST TUE NOV 22 2011
AFTER A QUIET WEEK INTO FRIDAY...THE WEATHER PATTERN BECOMES MORE
ACTIVE THIS WEEKEND INTO EARLY NEXT WEEK. RAIN WILL BECOME MORE
WIDESPREAD ALONG THE AFOREMENTIONED FRONT FRIDAY NIGHT INTO
SATURDAY AS A NORTHERN STREAM TROUGH BRIEFLY PHASES WITH A
SOUTHERN STREAM TROUGH. PLENTY OF QG FORCING WILL BE PROVIDED FROM
THIS FEATURE WHILE LOW LEVEL MOISTURE TRANSPORT CONTINUES TO PUMP
MOISTURE NORTHWARD FROM THE GULF. THE TREND HAS BEEN TO GO A BIT
FURTHER TO THE SOUTHEAST WITH THE BEST CHANCES FOR GETTING THIS
RAIN FRIDAY NIGHT INTO SATURDAY WITH THE MAIN BAND SETTING UP
ACROSS EASTERN IOWA INTO CENTRAL WISCONSIN.
AS THIS SYSTEM MOVES OFF TO THE EAST THE NORTHERN STREAM TROUGH
WILL PROPAGATE OFF TO THE NORTHEAST THROUGH CANADA WHILE THE
SOUTHERN STREAM TROUGH GETS CUT OFF AND LINGERS AROUND THE GREAT
LAKES INTO EARLY NEXT WEEK. CONFIDENCE IS RATHER LOW IN WHERE THIS
LOW WILL TRACK AS THE 22.12Z GFS IS FURTHER EAST WITH THE CORE OF
THE LOW AND PULLS SOME SIGNIFICANTLY COLDER AIR DOWN INTO THE
REGION ON TUESDAY WITH 850MB TEMPERATURES DROPPING TO AROUND -15C.
COMPARE THAT TO THE 22.12Z ECMWF WHICH IS FURTHER WEST WITH THE
LOW AND KEEPS PRECIPITATION ACROSS THE REGION LONGER INTO TUESDAY.
SOME SNOW WILL BE POSSIBLE ON THE BACK SIDE OF THE SYSTEM...BUT
WHEN AND WHERE IT WILL FALL IS STILL UP IN THE AIR AND THIS POINT.
&&
.AVIATION...THROUGH 06Z THURSDAY
1135 PM CST TUE NOV 22 2011
BIGGEST QUESTION CONTINUES TO BE CEILING HEIGHTS AND VISIBILITIES
THROUGH 18Z WEDNESDAY. STRATUS HAD MOVED BACK OVER THE TAF SITES
THIS EVENING. MODEL TRENDS IN BOTH THE 23.00Z NAM AND 23.02Z RUC
SHOW LOW LEVEL SATURATION TO CONTINUE WITH A STEADY DECREASE IN
CEILING HEIGHTS THROUGHOUT THE NIGHT. SOUNDINGS SUGGEST CEILINGS
TO LOWER INTO THE IFR CATEGORY AT KRST...BUT REMAIN IN THE LOWER
MVFR CATEGORY AT KLSE. LOWEST CEILINGS LOOK TO BE FROM 06Z-15Z
WEDNESDAY. WITH THE STRATUS FILLING BACK IN...VISIBILITIES SHOULD
REMAIN IN THE 2SM-4SM RANGE AT BOTH SITES. LATEST MODELS DO
INDICATE THE LOW LEVEL MOISTURE TO REMAIN TRAPPED UNDER THE
INVERSION ON WEDNESDAY. HOWEVER...THIS MOISTURE DOES THIN OUT AS
925MB WINDS BECOME MORE SOUTHWESTERLY. DID BACK UP THE CLEARING
TREND IN THE 06Z TAFS WITH CLOUDS SCATTERING OUT AROUND 17Z AT
KRST AND 20Z AT KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
219 PM CST TUE NOV 22 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS ALBANY NY
133 AM EST FRI NOV 25 2011
.SYNOPSIS...
THE WEATHER PATTERN WILL BE TRANQUIL FOR THIS HOLIDAY WEEKEND WITH
HIGH PRESSURE REMAINING IN CONTROL ALONG THE EASTERN SEABOARD.
TEMPERATURES WILL SLOWLY MODERATE TO ABOVE NORMAL AS SOUTHERLY WINDS
INCREASE. THE NEXT CHANCE FOR SHOWERS ARRIVES LATE SUNDAY INTO
MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1 AM...ONLY SOME MINOR ADJUSTMENTS BASED ON OBSERVATIONAL
DATA...FORECAST ON TRACK.
AS OF 1000 PM EST...THE IR SATELLITE PICTURE SHOWS SOME THIN CIRRUS
MOVING ACROSS ERN NY. NORTH AND WEST OF THE CAPITAL REGION... SOME
STRATUS IS STILL LINGERING OVER THE ADIRONDACKS. THE MOSTLY CLEAR
SKIES AND LIGHT TO CALM WINDS HAVE ALLOWED SOME PATCHY RADIATIONAL
FOG FORMATION OVER MUCH OF THE FCST AREA. THE SFC SOILS ARE STILL
A BIT WET FROM THE HVY RAINFALL ON TUESDAY NIGHT-WED. THE FOG IS
MOST ROBUST OVER THE LAKE GEORGE REGION...AND EAST OF THE SRN
GREEN MTNS. WE HAVE ADDED PATCHY FOG OVERNIGHT FOR LOCATIONS LESS
THAN 1000 FEET ACROSS ERN NY AND WRN NEW ENGLAND. TEMPS VARY
WIDELY ACROSS THE REGION WITH MINS REACHED OR EXCEEDED OVER THE
LAKE GEORGE REGION...AND THE BERKSHIRES. WE HAVE BROUGHT MINS DOWN
A FEW DEGREES WHERE IT RADIATED QUICKLY OVER THE LAKE GEORGE
REGION...NRN AND CNTRL TACONICS...AND THE BERKSHIRES. EXPECT LOWS
TO RANGE FROM THE M20S TO M30S ACROSS THE REGION. A WEAK THERMAL
TROUGH WILL MOVE THROUGH THE REGION OVERNIGHT...AND WE ARE SEEING
WINDS INCREASE FROM THE S/SW OVER W-CNTRL NY. TEMPS MAY ACTUALLY
CREEP UP A FEW DEGREES TOWARD SUNRISE.
PREVIOUS NEAR TERMS...
AS OF 630 PM EST...HAPPY THANKSGIVING TO ALL ! HIGH PRESSURE AT
THE SFC CONTINUES TO RIDGE IN FROM THE TN VALLEY AND THE MID
ATLANTIC REGION. A WEAK IMPULSE IN THE H500 W/NW FLOW ALOFT
CONTINUES TO MOVE ACROSS THE ERN GREAT LAKES REGION...AND UPSTATE
NY. THE STRATUS IS HANGING TOUGH ON THE 11-3.9 MICRON SATELLITE
LOOP NORTH AND WEST OF THE CAPITAL REGION. WE INCREASED THE CLOUD
COVER THROUGH MIDNIGHT OVER THE SRN AND WRN DACKS. THE NAM12 MODEL
SOUNDINGS...AND RH PROFILES INDICATE THIS STRATUS WILL HANG ON.
THE OTHER ISSUE TO DEAL WITH IS THE SKIES CLEARING...AND THE WINDS
GOING LIGHT TO CALM FROM THE HUDSON RIVER VALLEY EASTWARD. KGFL HAS
DROPPED TO ABOUT 30F WITH SOME PATCHY FOG FORMING. WE ADDED SOME
PATCHY FOG TO THE KGFL GENERAL AREA...AND TO THE CT RIVER VALLEY
EAST OF THE SRN GREEN MTNS. HOURLY TRENDS WERE REDONE BASED ON
OBSERVATIONS FOR T/TD/RH/APPARENT TEMPS. ASIDE FOR A FEW CIRRUS
FROM THE CAPITAL REGION SOUTH AND EAST OVERNIGHT...EXPECT TEMPS TO
COOL INTO THE U20S TO M30S.
PREVIOUS NEAR TERM...
STRATUS DECK WAS ALONG THE I90 CORRIDOR AS OF 19Z. THIS CLOUD DECK
CONTINUES TO SLOWLY ERODE AND MIGRATE NORTHWARD THIS AFTERNOON.
NCEP MODEL SUITE AND HOURLY RUC13 LOW LEVEL RH FIELDS SUGGEST THIS
STRATUS DECK SHOULD CONTINUE TO LIFT NORTHWARD AND ERODE FURTHER.
MEANWHILE...WARM ADVECTION ALOFT AND ITS ASSOCIATED HIGH AND SOME
MID LEVEL CLOUDS ARE QUICKLY MOVING ACROSS NEW ENGLAND AND
PORTIONS OF UPSTATE NEW YORK. THIS TOO IS EXPECTED TO SLIDE
OFFSHORE TONIGHT LEAVING BEHIND A PTCLOUDY-MOCLEAR SKIES.
BASED ON CURRENT DEWPOINTS...MOS TEMPERATURES LOOK A BIT COOL AND
HAVE FOLLOWED WARMER OVERNIGHT TRENDS WITHIN THE LAV/LAMP
GUIDANCE.
LARGE AREA OF HIGH PRESSURE...CENTERED OVER THE SOUTHEAST
CONUS...WILL BE THE DOMINANT PLAYER FOR THIS NEAR TERM AND INTO
THE SHORT TERM.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THIS LARGE AREA OF HIGH PRESSURE WILL KEEP THE WEATHER QUIET EAST
OF THE MISSISSIPPI RIVER THROUGH THIS SHORT TERM PERIOD. IN
FACT...RATHER PRONOUNCED WEST-SOUTHWEST FLOW ALONG WITH MILD MID
LEVEL TEMPS WILL RESULT IN TEMPERATURES CLIMBING TOWARD OR
EXCEEDING 10 DEGREES ABOVE CLIMATOLOGY /IN ADDITION...DOWNSLOPING
MAY ENHANCE THESE TEMPS INTO THE VALLEY LOCATIONS/. THE ONLY
COMPLICATION COULD BE SOME OVERNIGHT SHALLOW BR/FG AND A POTENTIAL
FOR SOME LOW LEVEL STRATUS DEVELOPMENT. IN ADDITION...WITH THE
ONGOING WARM ADVECTION...SOME HIGH AND MID LEVEL CLOUD COVER MAY
MOVE ACROSS THE SKY THOUGH THIS PERIOD. EITHER WAY...THE WEATHER
SHOULD HAVE MINIMAL IMPACT TO HOLIDAY WEEKEND TRAVELS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ACTIVE WEATHER PATTERN EXPECTED THROUGH THE LONG TERM...BUT MODEL
GUIDANCE HAS DIFFERING SOLUTIONS...SO CONFIDENCE IS LOW. WENT WITH
HPC GUIDANCE.
SFC LOW APPROACHING FROM THE GREAT LAKES REGION SUNDAY MORNING. 12Z
GFS...ECMWF AND GFSENSEMBLE MEMBERS HAVE NOT AGREED UPON A
TRACK...SPEED...OR QPF AMOUNTS. ECMWF HAS THE MORE PROGRESSIVE AND
NORTHERLY TRACK OF SFC LOW...WITH THE COLD FRONT AND PRECIP
ASSOCIATED WITH THE LOW MOVING THROUGH THE FA LATE SUNDAY THROUGH
LATE MONDAY...WITH QPF AMOUNTS AROUND HALF AN INCH OR LESS.
ASSOCIATED UPPER LEVEL POSITIVELY TILTED TROUGH REMAINS OPEN IN
ECMWF.
MEANWHILE...GFS DEVELOPS A CLOSE LOW WITHIN THE UPPER LEVEL TROUGH.
AS THIS TROUGH APPEARS TO HAVE A NEUTRAL TILT...GFS KEEPS IT SLOW
MOVING OVER THE GREAT LAKES REGION...WHERE THE UPPER LEVEL LOW
PRESSURE CENTER REFORMS FURTHER NORTH SUNDAY NIGHT. THE TROUGH
BECOMES NEGATIVELY TILTED BEFORE A PIECE OF SOUTHERLY ENERGY BREAKS
OFF...TRAVELING TOWARDS THE OBX AHEAD OF THE MAIN TROUGH...BY
TUESDAY NIGHT. QPF AMOUNTS UP TO 2 INCHES WITH THE GFS.
CHANCE FOR PRECIP POSSIBLE THROUGH TUESDAY NIGHT/WEDNESDAY WITH GFS
ENSEMBLE MEMBERS SLOWLY MOVE SFC LOW NORTHWARD TOWARDS JAMES BAY.
ALL GUIDANCE SHOW HIGH PRESSURE BUILDING IN JUST SOUTH OF THE
REGION...BUT NO AGREEMENT ON WHEN OR FOR HOW LONG. HPC HAS HIGH
PRESSURE WEDNESDAY INTO THURSDAY.
TEMPS ABOUT 10 DEGREES ABOVE NORMAL TO START THE PERIOD...TRENDING
COOLER TO ABOUT NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
IFR/LIFR CONDITIONS OCCURRING AT KGFL...KAQW...KDDH...KPOU...
AND KRME AT PRESENT...MVFR AT KPSF...AND VFR AT KALB.
LOW STRATUS DECK CONTINUES ACROSS MUCH OF THE ADIRONDACK REGION
INCLUDING SOME OF THE UPPER MOHAWK VALLEY WHILE FARTHER SOUTH
SKIES WERE MOSTLY CLEAR WITH SOME SCTD CIRRIFORM CLOUDS.
RADIATIONAL COOLING AND CALM WINDS WAS CAUSING FOG TO FORM IN
MANY LOCATIONS ACROSS THE REGION.
LOOKS LIKE KGFL WILL BE SOCKED IN FOR THE REST OF THE PREDAWN
PERIOD...DEAD CALM WITH IFR/LIFR CIG AND VSBY FOR THE LAST TWO
HOURS.
KALB...GOOD BET TO DETERIORATE TO MVFR BY 06Z...AND AT THIS
POINT CANNOT RULE OUT IFR DUE TO FOG OR STRATUS. WINDS DEAD
CALM...AND TEMP/DEWPT SPREAD ONLY 1 TO 2 DEGREES...THUS WILL
TEMPO TO IFR BETWEEN 07Z AND 11Z.
KPOU...SKY CURRENTLY CLEAR ASIDE FROM CIRRIFORM CLOUDS...AGAIN
DEAD CALM WINDS AND A 2 DEGREE TEMP/DEWPT SPREAD...SO LOOKING
AT MVFR A GOOD BET AND AGAIN A POSSIBILITY OF IFR DURING THE
PREDAWN PERIOD.
THE GOOD NEWS...SKIES SHOULD BE MOSTLY CLEAR ABOVE THE FOG AND
LOW STRATUS ASIDE FROM SOME STRANDS OF CIRRUS BY SUNRISE. THUS
THE FOG AND LOW STRATUS SHOULD MIX OUT BY 13Z-14Z. A FINE DAY
FOR VFR FLIGHT FOLLOWS WITH STRANDS OF CIRRUS STREAMING IN FROM
A FRONTAL SYSTEM IN THE MISSISSIPPI VALLEY AROUND THE NORTH SIDE
OF A HIGH PRESSURE SYSTEM CENTERED IN THE DEEP SOUTH.
WINDS WILL BE CALM...OR NEARLY SO...DURING THE PREDAWN PERIOD.
THEY WILL BECOME SOUTHERLY 3 TO 6 KNOTS SHORTLY AFTER SUNRISE
AND INCREASE TO AROUND 8 TO 12 KNOTS DURING THE MIDDAY PERIOD.
WINDS WILL THEN SLACKEN THIS EVENING TO LESS THAN 5 KNOTS.
OUTLOOK...
TONIGHT...MOSTLY VFR...SOME MVFR DUE TO LIGHT FOG POSSIBLE LATE.
SAT-SAT NIGHT...VFR. NO SIG WX.
SUN...MAINLY VFR. INCREASING CLDS. CHC PM -SHRAS.
SUN NIGHT-TUE...MVFR/IFR WITH CHC -SHRAS.
&&
.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH MOST OF THE LONG HOLIDAY WEEKEND
AS HIGH PRESSURE DOMINATES. OUR NEXT CHANCES FOR WET WEATHER WILL
RETURN LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS A LOW PRESSURE
SYSTEM APPROACHES AND MOVES ACROSS THE REGION. THERE IS A LOT OF
UNCERTAINTY DUE TO DIFFERENCES IN THE MODELS...BUT THERE IS A
POTENTIAL FOR SIGNIFICANT RAINFALL STARTING SUNDAY NIGHT...WITH
ONE TO TWO INCH AMOUNTS NOT OUT OF THE QUESTION. THE LATEST MMEFS
INDICATES SIGNIFICANT WITHIN-BANK RISES ON THE RIVERS BUT STOPPING
SHORT OF REACHING FLOOD.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
2011 HAS MOVED UP INTO FIFTH PLACE FOR WETTEST YEARS ON RECORD
FOR ALBANY NEW YORK.
WETTEST YEARS - ALBANY NY - SINCE 1820
1) 55.78 INCHES 1871
2) 55.81 INCHES 1870
3) 51.83 INCHES 1850
4) 49.80 INCHES 1827
5) 49.75 INCHES THROUGH NOVEMBER 23ND
6) 49.37 INCHES 1878
7) 48.35 INCHES 1843
8) 48.22 INCHES 1848
9) 47.79 INCHES 2008
10) 47.72 INCHES 2005
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...IAA/BGM/WASULA
SHORT TERM...BGM
LONG TERM...KGM
AVIATION...RCK
HYDROLOGY...RCK/BGM
CLIMATE...IAA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1245 AM EST FRI NOV 25 2011
.SYNOPSIS...
THE WEATHER PATTERN WILL BE TRANQUIL FOR THIS HOLIDAY WEEKEND WITH
HIGH PRESSURE REMAINING IN CONTROL ALONG THE EASTERN SEABOARD.
TEMPERATURES WILL SLOWLY MODERATE TO ABOVE NORMAL AS SOUTHERLY WINDS
INCREASE. THE NEXT CHANCE FOR SHOWERS ARRIVES LATE SUNDAY INTO
MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1000 PM EST...THE IR SATELLITE PICTURE SHOWS SOME THIN
CIRRUS MOVING ACROSS ERN NY. NORTH AND WEST OF THE CAPITAL REGION...
SOME STRATUS IS STILL LINGERING OVER THE ADIRONDACKS. THE MOSTLY
CLEAR SKIES AND LIGHT TO CALM WINDS HAVE ALLOWED SOME PATCHY
RADIATIONAL FOG FORMATION OVER MUCH OF THE FCST AREA. THE SFC
SOILS ARE STILL A BIT WET FROM THE HVY RAINFALL ON TUESDAY NIGHT-WED.
THE FOG IS MOST ROBUST OVER THE LAKE GEORGE REGION...AND EAST OF
THE SRN GREEN MTNS. WE HAVE ADDED PATCHY FOG OVERNIGHT FOR
LOCATIONS LESS THAN 1000 FEET ACROSS ERN NY AND WRN NEW ENGLAND.
TEMPS VARY WIDELY ACROSS THE REGION WITH MINS REACHED OR EXCEEDED
OVER THE LAKE GEORGE REGION...AND THE BERKSHIRES. WE HAVE BROUGHT
MINS DOWN A FEW DEGREES WHERE IT RADIATED QUICKLY OVER THE LAKE
GEORGE REGION...NRN AND CNTRL TACONICS...AND THE BERKSHIRES.
EXPECT LOWS TO RANGE FROM THE M20S TO M30S ACROSS THE REGION. A
WEAK THERMAL TROUGH WILL MOVE THROUGH THE REGION OVERNIGHT...AND
WE ARE SEEING WINDS INCREASE FROM THE S/SW OVER W-CNTRL NY. TEMPS
MAY ACTUALLY CREEP UP A FEW DEGREES TOWARD SUNRISE.
PREVIOUS NEAR TERMS...
AS OF 630 PM EST...HAPPY THANKSGIVING TO ALL ! HIGH PRESSURE AT
THE SFC CONTINUES TO RIDGE IN FROM THE TN VALLEY AND THE MID
ATLANTIC REGION. A WEAK IMPULSE IN THE H500 W/NW FLOW ALOFT
CONTINUES TO MOVE ACROSS THE ERN GREAT LAKES REGION...AND UPSTATE
NY. THE STRATUS IS HANGING TOUGH ON THE 11-3.9 MICRON SATELLITE
LOOP NORTH AND WEST OF THE CAPITAL REGION. WE INCREASED THE CLOUD
COVER THROUGH MIDNIGHT OVER THE SRN AND WRN DACKS. THE NAM12 MODEL
SOUNDINGS...AND RH PROFILES INDICATE THIS STRATUS WILL HANG ON.
THE OTHER ISSUE TO DEAL WITH IS THE SKIES CLEARING...AND THE WINDS
GOING LIGHT TO CALM FROM THE HUDSON RIVER VALLEY EASTWARD. KGFL HAS
DROPPED TO ABOUT 30F WITH SOME PATCHY FOG FORMING. WE ADDED SOME
PATCHY FOG TO THE KGFL GENERAL AREA...AND TO THE CT RIVER VALLEY
EAST OF THE SRN GREEN MTNS. HOURLY TRENDS WERE REDONE BASED ON
OBSERVATIONS FOR T/TD/RH/APPARENT TEMPS. ASIDE FOR A FEW CIRRUS
FROM THE CAPITAL REGION SOUTH AND EAST OVERNIGHT...EXPECT TEMPS TO
COOL INTO THE U20S TO M30S.
PREVIOUS NEAR TERM...
STRATUS DECK WAS ALONG THE I90 CORRIDOR AS OF 19Z. THIS CLOUD DECK
CONTINUES TO SLOWLY ERODE AND MIGRATE NORTHWARD THIS AFTERNOON.
NCEP MODEL SUITE AND HOURLY RUC13 LOW LEVEL RH FIELDS SUGGEST THIS
STRATUS DECK SHOULD CONTINUE TO LIFT NORTHWARD AND ERODE FURTHER.
MEANWHILE...WARM ADVECTION ALOFT AND ITS ASSOCIATED HIGH AND SOME
MID LEVEL CLOUDS ARE QUICKLY MOVING ACROSS NEW ENGLAND AND
PORTIONS OF UPSTATE NEW YORK. THIS TOO IS EXPECTED TO SLIDE
OFFSHORE TONIGHT LEAVING BEHIND A PTCLOUDY-MOCLEAR SKIES.
BASED ON CURRENT DEWPOINTS...MOS TEMPERATURES LOOK A BIT COOL AND
HAVE FOLLOWED WARMER OVERNIGHT TRENDS WITHIN THE LAV/LAMP
GUIDANCE.
LARGE AREA OF HIGH PRESSURE...CENTERED OVER THE SOUTHEAST
CONUS...WILL BE THE DOMINANT PLAYER FOR THIS NEAR TERM AND INTO
THE SHORT TERM.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THIS LARGE AREA OF HIGH PRESSURE WILL KEEP THE WEATHER QUIET EAST
OF THE MISSISSIPPI RIVER THROUGH THIS SHORT TERM PERIOD. IN
FACT...RATHER PRONOUNCED WEST-SOUTHWEST FLOW ALONG WITH MILD MID
LEVEL TEMPS WILL RESULT IN TEMPERATURES CLIMBING TOWARD OR
EXCEEDING 10 DEGREES ABOVE CLIMATOLOGY /IN ADDITION...DOWNSLOPING
MAY ENHANCE THESE TEMPS INTO THE VALLEY LOCATIONS/. THE ONLY
COMPLICATION COULD BE SOME OVERNIGHT SHALLOW BR/FG AND A POTENTIAL
FOR SOME LOW LEVEL STRATUS DEVELOPMENT. IN ADDITION...WITH THE
ONGOING WARM ADVECTION...SOME HIGH AND MID LEVEL CLOUD COVER MAY
MOVE ACROSS THE SKY THOUGH THIS PERIOD. EITHER WAY...THE WEATHER
SHOULD HAVE MINIMAL IMPACT TO HOLIDAY WEEKEND TRAVELS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ACTIVE WEATHER PATTERN EXPECTED THROUGH THE LONG TERM...BUT MODEL
GUIDANCE HAS DIFFERING SOLUTIONS...SO CONFIDENCE IS LOW. WENT WITH
HPC GUIDANCE.
SFC LOW APPROACHING FROM THE GREAT LAKES REGION SUNDAY MORNING. 12Z
GFS...ECMWF AND GFSENSEMBLE MEMBERS HAVE NOT AGREED UPON A
TRACK...SPEED...OR QPF AMOUNTS. ECMWF HAS THE MORE PROGRESSIVE AND
NORTHERLY TRACK OF SFC LOW...WITH THE COLD FRONT AND PRECIP
ASSOCIATED WITH THE LOW MOVING THROUGH THE FA LATE SUNDAY THROUGH
LATE MONDAY...WITH QPF AMOUNTS AROUND HALF AN INCH OR LESS.
ASSOCIATED UPPER LEVEL POSITIVELY TILTED TROUGH REMAINS OPEN IN
ECMWF.
MEANWHILE...GFS DEVELOPS A CLOSE LOW WITHIN THE UPPER LEVEL TROUGH.
AS THIS TROUGH APPEARS TO HAVE A NEUTRAL TILT...GFS KEEPS IT SLOW
MOVING OVER THE GREAT LAKES REGION...WHERE THE UPPER LEVEL LOW
PRESSURE CENTER REFORMS FURTHER NORTH SUNDAY NIGHT. THE TROUGH
BECOMES NEGATIVELY TILTED BEFORE A PIECE OF SOUTHERLY ENERGY BREAKS
OFF...TRAVELING TOWARDS THE OBX AHEAD OF THE MAIN TROUGH...BY
TUESDAY NIGHT. QPF AMOUNTS UP TO 2 INCHES WITH THE GFS.
CHANCE FOR PRECIP POSSIBLE THROUGH TUESDAY NIGHT/WEDNESDAY WITH GFS
ENSEMBLE MEMBERS SLOWLY MOVE SFC LOW NORTHWARD TOWARDS JAMES BAY.
ALL GUIDANCE SHOW HIGH PRESSURE BUILDING IN JUST SOUTH OF THE
REGION...BUT NO AGREEMENT ON WHEN OR FOR HOW LONG. HPC HAS HIGH
PRESSURE WEDNESDAY INTO THURSDAY.
TEMPS ABOUT 10 DEGREES ABOVE NORMAL TO START THE PERIOD...TRENDING
COOLER TO ABOUT NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
IFR/LIFR CONDITIONS OCCURRING AT KGFL...KAQW...KDDH...KPOU...
AND KRME AT PRESENT...MVFR AT KPSF...AND VFR AT KALB.
LOW STRATUS DECK CONTINUES ACROSS MUCH OF THE ADIRONDACK REGION
INCLUDING SOME OF THE UPPER MOHAWK VALLEY WHILE FARTHER SOUTH
SKIES WERE MOSTLY CLEAR WITH SOME SCTD CIRRIFORM CLOUDS.
RADIATIONAL COOLING AND CALM WINDS WAS CAUSING FOG TO FORM IN
MANY LOCATIONS ACROSS THE REGION.
LOOKS LIKE KGFL WILL BE SOCKED IN FOR THE REST OF THE PREDAWN
PERIOD...DEAD CALM WITH IFR/LIFR CIG AND VISBY FOR THE LAST
TWO HOURS.
KALB...GOOD BET TO DETERIORATE TO MVFR BY 06Z...AND AT THIS
POINT CANNOT RULE OUT IFR DUE TO FOG OR STRATUS. WINDS DEAD
CALM...AND TEMP/DEWPT SPREAD ONLY 1 TO 2 DEGREES...THUS WILL
TEMPO TO IFR BETWEEN 07Z AND 11Z.
KPOU...SKY CURRENTLY CLEAR ASIDE FROM CIRRIFORM CLOUDS...AGAIN
DEAD CALM WINDS AND A 2 DEGREE TEMP/DEWPT SPREAD...SO LOOKING
AT MVFR A GOOD BET AND AGAIN A POSSIBILITY OF IFR DURING THE
PREDAWN PERIOD.
THE GOOD NEWS...SKIES SHOULD BE MOSTLY CLEAR ABOVE THE FOG AND
LOW STRATUS ASIDE FROM SOME STRANDS OF CIRRUS BY SUNRISE. THUS
THE FOG AND LOW STRATUS SHOULD MIX OUT BY 13Z-14Z. A FINE DAY
FOR VFR FLIGHT FOLLOWS WITH STRANDS OF CIRRUS STREAMING IN FROM
A FRONTAL SYSTEM IN THE MISSISSIPPI VALLEY AROUND THE NORTH SIDE
OF A HIGH PRESSURE SYSTEM CENTERED IN THE DEEP SOUTH.
WINDS WILL BE CALM...OR NEARLY SO...DURING THE PREDAWN PERIOD.
THEY WILL BECOME SOUTHERLY 3 TO 6 KNOTS SHORTLY AFTER SUNRISE
AND INCREASE TO AROUND 8 TO 12 KNOTS DURING THE MIDDAY PERIOD.
WINDS WILL THEN SLACKEN THIS EVENING TO LESS THAN 5 KNOTS.
OUTLOOK...
TONIGHT...MOSTLY VFR...SOME MVFR DUE TO LIGHT FOG POSSIBLE LATE.
SAT-SAT NIGHT...VFR. NO SIG WX.
SUN...MAINLY VFR. INCREASING CLDS. CHC PM -SHRAS.
SUN NIGHT-TUE...MVFR/IFR WITH CHC -SHRAS.
&&
.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH MOST OF THE LONG HOLIDAY WEEKEND
AS HIGH PRESSURE DOMINATES. OUR NEXT CHANCES FOR WET WEATHER WILL
RETURN LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS A LOW PRESSURE
SYSTEM APPROACHES AND MOVES ACROSS THE REGION. THERE IS A LOT OF
UNCERTAINTY DUE TO DIFFERENCES IN THE MODELS...BUT THERE IS A
POTENTIAL FOR SIGNIFICANT RAINFALL STARTING SUNDAY NIGHT...WITH
ONE TO TWO INCH AMOUNTS NOT OUT OF THE QUESTION. THE LATEST MMEFS
INDICATES SIGNIFICANT WITHIN-BANK RISES ON THE RIVERS BUT STOPPING
SHORT OF REACHING FLOOD.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
2011 HAS MOVED UP INTO FIFTH PLACE FOR WETTEST YEARS ON RECORD
FOR ALBANY NEW YORK.
WETTEST YEARS - ALBANY NY - SINCE 1820
1) 55.78 INCHES 1871
2) 55.81 INCHES 1870
3) 51.83 INCHES 1850
4) 49.80 INCHES 1827
5) 49.75 INCHES THROUGH NOVEMBER 23ND
6) 49.37 INCHES 1878
7) 48.35 INCHES 1843
8) 48.22 INCHES 1848
9) 47.79 INCHES 2008
10) 47.72 INCHES 2005
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...BGM/WASULA
SHORT TERM...BGM
LONG TERM...KGM
AVIATION...RCK
HYDROLOGY...RCK/BGM
CLIMATE...IAA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1110 PM CST THU NOV 24 2011
.DISCUSSION...
ISSUED 852 PM CST THU NOV 24 2011
LOW STRATUS IS COMING BACK NORTH...AIDED BY STRONG SOUTHERLY
WINDS. THIS AREA OF CLOUDS IS NOT VERY WIDE SO SOME AREAS IN THE
SOUTHEAST COULD SEE SOME CLEARING OVERNIGHT...WHILE OTHER AREAS
BECOME CLOUDY AGAIN. CURRENT FORECAST SEEMS TO HAVE A GOOD HANDLE
ON THE GOING TRENDS SO NO UPDATE REQUIRED AT THIS TIME.
HOWEVER...HAVE BEEN MAKING ADJUSTMENTS TO THE GRIDS TO BETTER
REFLECT THE CLOUD COVER TRENDS.
AUTEN
&&
.AVIATION...
ISSUED 1110 PM CST THU NOV 24 2011
IFR CIGS/VIS ARE ONCE AGAIN ADVECTING NORTHWARD OVER THE TAF
SITES. DEC/CMI ALREADY DOWN AND EXPECT SPI AND BMI TO BE IFR
AROUND ISSUANCE TIME. UNSURE IF PIA WILL SEE IT GIVEN THE FACT
THAT THE SATELLITE LOOP SEEMS TO INDICATE A SLOWING TREND IN THE
MOVEMENT NORTH. SATELLITE ALSO SHOWS SOME HOLES IN THE STRATUS.
ONCE STRATUS DISSIPATES TOMORROW MORNING VFR CONDITIONS WILL
PREVAIL FOR REMAINDER OF TAF PERIOD. SCATTERED CIRRUS BECOMING
BROKEN AROUND 18Z IS ALL THAT IS EXPECTED. MODELS AND BUFKIT
SOUNDING CONTINUE TO INDICATE LOW LEVEL WIND SHEAR AROUND 1.5KFT
TONIGHT SO WILL KEEP MENTION. ONCE STRATUS CLEARS...EXPECTING
SOUTHERLY WINDS TO INCREASE AND BE GUSTY DURING THE
AFTERNOON...THEN DECREASING AROUND SUNSET. SOUTHERLY WINDS WILL
PREVAIL THROUGH THE PERIOD.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 300 PM CST THU NOV 24 2011
INITIAL CONCERN WILL BE POSSIBLE REDEVELOPMENT OF LOW STRATUS
CLOUDS TONIGHT INTO FRIDAY MORNING. THEN ATTENTION TURNS TO THE
ONSET OF RAIN LATE FRIDAY NIGHT THROUGH SATURDAY AND THE ARRIVAL
OF COLDER AIR FOR MUCH OF THE EXTENDED FORECAST.
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
CHALLENGING FORECAST FOR TONIGHT IN TERMS OF CLOUDS AND RESULTANT
LOW TEMPS. THE ONLY MODELS THAT SEEM TO HAVE A DECENT HANDLE ON
THE LOW LEVEL MOISTURE ARE THE HRRR AND SPC 4KM WRF. BOTH OF THEM
ARE INDICATING CLOUD REDEVELOPMENT ACROSS CENTRAL IL AND EVEN
SURROUNDING PORTIONS OF IL. THE NAM AND GFS SOUNDINGS SHOW A LOW
LEVEL SATURATION AS WELL...BUT SHALLOW. FORECAST WIND TRAJECTORY
FLOWS INDICATE WE SHOULD SEE THE SW RETURN FLOW ORIGINATING WHERE
STRATUS CLOUDS ARE LINGERING THIS AFTERNOON IN MO/AR. A TIGHTER
PRESSURE GRADIENT WOULD TYPICALLY KEEP WINDS UP AT NIGHT...BUT THE
LOW LEVEL INVERSION LOOKS TO BE PLENTY STRONG ENOUGH TO PREVENT
MIXING OVERNIGHT. WILL FORECAST CLOUDS TO REFORM...AND KEEP LOW
TEMPS A COUPLE DEGREES WARMER THAN GUIDANCE.
CLEARING SHOULD COME QUICKER ON FRIDAY AS MORE PROMINENT MIXING
WILL OCCUR UNDER A MUCH STRONGER SFC PRESSURE GRADIENT. PLENTY OF
DRY AIR ALOFT WILL AID IN CLOUD EROSION. WINDY CONDITIONS ARE
EXPECTED WITH SSW GUSTS OVER 30 MPH. TEMPS WILL RESPOND IN KIND AS
WAA FLOWS PUSH 850 MB TEMPS UP NEAR 12C. THAT COUPLED WITH ADDITIONAL
SUNSHINE SHOULD PUT HIGHS INTO THE L-M 60S.
BROAD SCALE ISENTROPIC LIFT AHEAD OF THE NEXT COLD FRONT WILL HELP
PRIME THE ATMOSPHERE FOR RAIN TO DEVELOP W OF THE IL RIVER AFTER
MIDNIGHT FRIDAY NIGHT. HOWEVER...BASED ON FORECAST CONDENSATION
PRESSURE DEFICITS /CPD/...IT STILL APPEARS WE WILL HAVE A 5-7 HOUR
WINDOW OF STEADY RAINS AS THE FRONT PROGRESSES EASTWARD DURING THE
DAY ON SATURDAY. WE WILL CONTINUE WITH CATEGORICAL POPS WEST IN
THE MORNING AND EAST IN THE AFTERNOON. SOME SHOWERS MAY LINGER IN
THE EVENING ACROSS THE EAST...SO WILL CONTINUE WITH CHANCE POPS AS
SUBSIDENT FLOWS BEGIN TO SHUT DOWN MEASURABLE PRECIP.
COLD AIR WILL RETURN ON BRISK NW WINDS SAT NIGHT. MOST OF THE
PRECIP SHOULD COME TO AN END BEFORE THE AIR COLUMN GETS COLD
ENOUGH FOR SNOW. HOWEVER...WE CAN NOT RULE OUT SOME FLURRIES
POSSIBLE AFTER MIDNIGHT SAT NIGHT. BY 12Z SUNDAY...ANOTHER WAVE OF
ISENTROPIC LIFT AND LOW CPD/S IS INDICATED AS THE UPPER TROUGH MOVES
ACROSS IL. ENOUGH RESIDUAL MOISTURE MAY BE PRESENT FOR A FEW LIGHT
RAIN/SNOW SHOWERS AFTER MIDNIGHT...AND FLURRIES NORTH/SPRINKLES
SOUTH ON SUNDAY.
BY SUNDAY NIGHT...ALL PRECIP SHOULD COME TO AN END FROM THIS
SYSTEM...AS THE UPPER TROUGH AXIS FINALLY SLIDES EAST.
LONG TERM...MONDAY THROUGH THURSDAY.
THE EXTENDED FORECAST SHOWS PERSISTENT COLD CONDITIONS AS A CUT
OFF LOW POSSIBLY DEVELOPS ACROSS THE SOUTHERN OHIO RIVER VALLEY.
THERE HAS BEEN A WIDE VARIETY OF SOLUTIONS FROM THE MODELS ON THIS
CUT OFF FEATURE...WITH THE ECMWF AND THE CANADIAN THE MAIN ONES
SHOWING THIS FEATURE. THE ECMWF BEING A BIT MORE PRONOUNCED AND
SLOWER THAN THE CANADIAN. THE GFS KEEPS A PROGRESSIVE PATTERN WITH
NORTHWEST FLOW AND A DRY FRONTAL PASSAGE ON MONDAY NIGHT/TUESDAY
ACROSS IL. DESPITE THE DIFFERING SOLUTIONS...THE OVERALL SENSIBLE
WEATHER LOOKS TO BE ON THE CHILLY SIDE WITH PERIODICALLY BREEZY
CONDITIONS.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
315 AM CST FRI NOV 25 2011
...UPDATED FOR 06Z AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
STRATUS FIELD IS LIFTING THROUGH EASTERN KS AS LOW LEVEL MOISTURE
CONTINUES TO ADVECT NORTHWARD TOWARD IOWA. THE MOISTURE IS CENTERED
NEAR 950 MB. THE LATEST RUC 950 MB CONDENSATION PRESSURE DEFICITS
ARE HANDLING THE STRATUS PLACEMENT WELL AND SUGGESTS IT WILL SPREAD
NORTHEAST OVER MUCH OF CNTRL IA THIS MORNING. CIRRUS WILL ALSO BE
THICKENING OVER THE STATE TODAY AND IN COMBINATION WITH THE
STRATUS...WILL RESULT IN MOSTLY CLOUDY CONDITIONS. THIS WILL HAVE AN
IMPACT ON HIGH TEMPERATURES. READINGS AT 3 AM REMAIN QUITE MILD IN
THE MID TO UPPER 40S. ANY SUNSHINE THIS MORNING COULD QUICKLY PUSH
READINGS WELL INTO THE 50S. EXPECT CLOUDS TO BECOME PREVALENT BY MID
MORNING AND WILL LIMIT TEMPERATURES...THEREFORE HAVE TEMPERED HIGHS
FOR TODAY BACK A FEW DEGREES AND MORE INTO THE MID TO UPPER 50S.
THIS WILL BE TOO WARM IF THE STRATUS LINGERS ALL DAY.
THE INITIAL SHORT WAVE WILL REACH WESTERN IA BY THIS AFTERNOON WITH
INCREASING QG FORCING AND THE MID LEVEL DRY AIR SLOWLY ERODING AS
EVAPORATING PRECIPITATION FALLS INTO THIS LAYER. POSSIBLE BY VERY
LATE AFTERNOON THAT A FEW SPRINKLES OR LIGHT RAIN COULD REACH THE
SFC OVER THE FAR WEST CENTRAL AND SOUTHWEST. THEREFORE HAVE ADDED
LOW POPS.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
FORECAST PROBLEM IN THE LONG TERM CONTINUES TO BE THE UPPER TROUGH
MOVING THROUGH THE UPPER MIDWEST THIS WEEKEND. A NORTHERN STREAM
SHORTWAVE WAS MOVING EAST THROUGH THE NORTHERN ROCKIES THIS MORNING
WHILE A WEAKER SOUTHERN STREAM WAVE WAS MOVING THROUGH THE DESERT
SOUTHWEST. THE NORTHERN SYSTEM IS FORECAST TO MOVE SOUTHEAST INTO
THE CENTRAL UNITED STATES AND DEEPEN BY SATURDAY. THE 00Z GFS/NAM
PHASE THE TWO WAVES IN THE CENTRAL STATE AND SIGNIFICANTLY DEEPEN
THE TROUGH INTO A CLOSED 500 MB LOW. THE 00Z ECMWF REMAINS
CONSISTENT WITH IT/S PREVIOUS RUN KEEPING THE SHORT WAVE ENERGY
SEPARATE. AS A RESULT...THE NORTHERN SHORTWAVE REMAINS A POSITIVE
TILTED OPEN WAVE. THE GFS/NAM SOLUTIONS HAVE A MUCH DEEPER SURFACE
LOW WHICH DEVELOPS NORTHEAST OF CENTRAL IOWA. WITH THE DEEPER
SYSTEM...THE WIND FIELDS ARE STRONG. IF THE GFS/NAM SOLUTIONS
VERIFY...AT A MINIMUM CENTRAL IOWA SHOULD HAVE A DECENT WIND EVENT
AND SOME LIGHT SNOW DUE TO THE STRONGER FORCING. IF THE WEAKER
LOOKING ECMWF VERIFIES...IT WOULD BE WINDY...BUT PROBABLY BELOW
ADVISORY CRITERIA AND LESS SNOW CHANCES. BASED THE FORECAST ON A
COMPROMISE BETWEEN THESE VARIED SOLUTIONS. NO HEADLINES FOR WIND AT
THIS POINT...BUT WILL MENTION WINDY CONDITIONS IN THE HWO. WILL
ALSO MENTION THE POSSIBILITY OF LIGHT SNOW...ESPECIALLY NORTH...BUT
ACCUMULATIONS SHOULD BE LIGHT.
MOISTURE STEAMING NORTHEAST AHEAD OF THE FRONT TONIGHT ALONG WITH A
LARGE AREA OF UPWARD FORCING AHEAD OF THE UPPER TROUGH SUPPORTS HIGH
POPS FOR RAIN TONIGHT.
ANOTHER COLD FRONT SHOULD MOVE THROUGH THE STATE LATE MONDAY. LACK
OF SIGNIFICANT FORCING AND MOISTURE SHOULD KEEP IT DRY. THE 00Z
ECMWF IS ADVERTISING A STRONGER COLD FRONT LATE NEXT WEEK.
CONFIDENCE ON THE TIMING OF THE FRONTS IS LOW DUE TO MODEL
DIFFERENCES NEXT WEEK BETWEEN THE ECMWF AND THE OPERATIONAL GFS.
&&
.AVIATION...25/06Z
STRONG SOUTHERLY FLOW WILL CONTINUE OVERNIGHT INTO FRIDAY AHEAD OF
APPROACHING SYSTEM. MOISTURE ADVECTING NORTHWARD IN LOW LEVEL JET
WILL ARRIVE IN IOWA TOWARD DAYBREAK WITH 950-900MB CDEFS DROPPING
QUICKLY. HAVE INCLUDED BROKEN STRATUS IN MOST TAFS BETWEEN 11Z AND
13Z WITH THE RAPID NORTHWARD EXPANSION. THE STATUS SHOULD PERSIST
FOR MUCH OF THE MORNING BUT MAY SEE SOME BREAKUP TOWARD AFTERNOON
WITH SOME HEATING...ALTHOUGH THE MAY BE OPTIMISTIC GIVEN THE CLIMO
THIS TIME OF YEAR. NEXT CONCERN WOULD BE WITH THE DEVELOPMENT OF
RAINFALL FRIDAY EVENING AS FRONT ENTERS THE STATE AND LARGE SCALE
ASCENT INCREASES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DONAVON
LONG TERM...JOHNSON
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
405 AM EST FRI NOV 25 2011
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT UPR
RDGING IN PLACE OVER NAMERICA DOWNSTREAM OF TROFFING OVER THE PAC NW
AND WRN CAN. CLOSER TO THE SFC...THE UPR GRT LKS ARE DOMINATED BY A
STRONG SW FLOW BTWN HI PRES IN THE MID ATLANTIC STATES AND LO PRES
OVER NRN ONTARIO. GRAND MARAIS IN ALGER COUNTY REPORTED SW WIND
GUSTS UP TO 37 MPH AT 0330Z. THE 00Z INL AND MPX RAOBS ARE QUITE DRY
/IN FACT...THE 00Z H7 DEWPT DEPRESSION AT ABERDEEN SDAKOTA WAS
42C/...SO NOTHING BUT HI CLDS ARE PRESENT ALONG AND AHEAD OF
ATTENDANT COLD FNT EXTENDING FM THE ONTARIO LO THRU NW MN INTO
NDAKOTA. MORE EXTENSIVE LO CLDS FOLLOW THE FROPA OVER NW NDAKOTA AND
SCNTRL CAN WITH SHALLOW COLD AIR INFUSION. OVER THE E HALF OF THE
CWA...LLVL MSTR DEPICTED ON THE 00Z GRB RAOB BLO SHARP INVRN BASE
NEAR H95 HAS RESULTED IN EXTENSIVE LO CLD. OTRW TEMPS ARE WELL ABV
NORMAL FOR THE SEASON...WITH 00Z H85 TEMPS RANGING FM 13C AT GRB AND
INL TO 15C AT MPX. SFC TEPS ARE STILL WELL INTO THE 40S AT MANY
PLACES EARLY THIS MRNG...10 TO 15 DEGREES ABV THE NORMAL HI TEMPS
FOR THE DATE. WELL TO THE W... WV IMAGERY INDICATES A STRONGER
SHRTWV IS APRCHG THE PAC NW...WHERE 12Z-24Z H3 FALLS UP TO 100M
OCCURRED.
&&
.DISCUSSION...
MAIN FCST CONCERNS SHIFT FM LO CLDS/WELL ABV NORMAL TEMPS TDAY TO
PCPN CHCS TNGT THRU THE WEEKEND.
TDAY...SFC HI PRES OVER THE MID ATLANTIC IS PROGGED TO DRIFT OFF THE
SE COAST WHILE LO PRES NOW OVER NRN ONTARIO WL DRIFT ACRS QUEBEC...
DRAGGING ATTENDANT COLD FNT INTO THE CWA DURING THE AFTN. ALTHOUGH
SFC TEMPS WL BE HELD DOWN ESPECIALLY OVER THE NW WITH THE ARRIVAL OF
LLVL COLDER AIR/ARRIVAL OF MORE LO CLDS BEHIND THE FROPA...READINGS
WL STILL BE WELL ABV NORMAL...ESPECIALLY OVER THE SCNTRL WHERE THE
LO CLDS ARE MORE LIKELY TO BREAK UP. THE SW FLOW OFF LK MI THRU THE
DAY AND LO SUN ANGLE WL LIKELY RESULT IN A PERSISTENCE OF THE LO CLD
OVER THE E EVEN THOUGH THE STRONGER SW WINDS OBSVD EARLY THIS MRNG
WL DIMINISH QUICKLY AS THE PRES GRADIENT SLACKENS. ALTHOUGH SOME
MODELS GENERATE LGT PCPN OVER THE CWA WITH THE COLD FROPA...PREFER
THE DRY NAM GIVEN THE EXCESSIVE MID LVL DRYNESS OBSVD UPSTREAM.
TNGT...STRONGER SHRTWV NOW MOVING INTO THE PAC NW IS FCST TO DEEPEN
UPR TROF IN THE PLAINS...WITH SFC LO PRES DVLPG OVER NW WI ON
STALLED FNT THAT WL REMAIN ACRS THE CWA. ALTHOUGH LINGERING MID LVL
DRY AIR WL LIMIT PCPN CHCS IN THE EVNG...EXPANDING DEEP LYR QVECTOR
CNVGC/UPR DVGC/SHARPENING H85-7 FGEN ASSOCIATED WITH APRCHG SHRTWV/
EXIT REGION OF ACCOMPANYING 120KT H3 JET MAX WL INCRS RA CHCS
ESPECIALLY OVER THE SW HALF LATER. TENDED TOWARD THE SOMEWHAT WETTER
00Z GFS/12Z ECMWF GIVEN APPARENT STRENGTH OF SHRTWV NOW APRCHG THE
PAC NW.
SAT...MODEL DISCREPANCIES BECOME MORE PRONOUNCED WITH THE HANDLING
OF THE DVLPG LO...SO CONFIDENCE IN THE FCST WL DIMINISH. GIVEN
APPARENT STRENGHT OF INCOMING SHRTWV AS MENTIONED ABOVE...TENDED
TOWARD THE DEEPER 00Z NAM/GFS SCENARIOS THAT SHOW CUTOFF H5 LO
FORMING SOMEWHERE OVER THE UPR MS RIVER VALLEY/UPR MIDWEST.
HOWEVER...NCEP PREFERENCE FOR THE WEAKER SOLNS SHOWN BY THE 12Z
ECMWF AND 00Z CNDN LOWER CONFIDENCE FURTHER. FORTUNATELY...THERE IS
RELATIVELY LTL DIFFERENCE IN THE SFC LO PLACEMENT AMONG THE VARIOUS
MODELS DESPITE THE DIFFERENCES IN INTENSITY. MODELS SHOW SFC LO
MOVING TO NEAR MQT BY 00Z SUN. ALTHOUGH DRY SLOTTING TO THE E OF THE
H5 LO WL LIKELY RESULT IN A DIMINISHING TREND OF THE PCPN OVER
MAINLY THE CNTRL AND E...EXPECT HEAVIER PCPN TO LINGER OVER THE W FM
IWD-CMX THRU THE DAY CLOSER TO THE TRACK OF THE ACCOMPANYING H85 LO.
PER GFS FCST WBLB ZERO HGT FCST TO FALL NEAR 1K FT AGL BY 00Z
SUN...EXPECT ENUF COLD AIR TO ARRIVE LATE IN THE DAY TO RESULT IN AT
LEAST A MIX OF RA/SN NEAR IWD UNDER THE SHARPER CYC NLY FLOW.
SAT NGT THRU SUN...VARIOUS MODELS SHOW SFC LO DRIFTING SLOWLY TO THE
NE TO SSE OF JAMES BAY BY LATE IN THE DAY SUN. THE NAM BECOMES A
PARTICULAR OUTLIER SHOWING THE LO LINGERING NEAR UPR MI...SO
REJECTED THIS FCST. THE OTHER PREFERRED MODELS SUG PCPN WITHIN COMMA
HEAD MSTR UNDER SHARPER NNW CYC FLOW/H85 THERMAL TROFFING WL IMPACT
MAINLY THE NW HALF AND SLOWLY CHG TO SN AS COLDER AIR MOVES OVHD...
WITH BOTH THE 00Z GFS/12Z ECMWF INDICATING H85 TEMPS FALLING TO ARND
-9C...LO ENUF FOR LK EFFECT PCPN CONSIDERING LK SUP TEMPS ARND 5C.
HOWEVER...EVEN THE DEEPER GFS SUGS SN GROWTH MICROPHYSICS WL NOT BE
VERY FVRBL GIVEN FCST WEAK UVV IN THE DENDRITIC SN GROWTH ZN. EVEN
SO...SOME LO END ADVY SN AMNTS MAY BE PSBL OVER THE W WITH LK
ENHANCEMENT AS THE SN SHOULD BE WET AND HEAVY. THE NEW 00Z ECMWF
INDICATES GOOD CONTINUITY WITH THE 12Z RUN...BUT SHOWS QUICKER
DRYING ON SUN WITH A WEAKER CYC FLOW/FASTER EXIT THAN INDICATED BY
THE DEEPER GFS. TENDED TOWARD HIER POPS OVER THE W TO THE HURON MTNS
WHERE THE UPSLOPE NNW FLOW WOULD HAVE A MORE SGNFT IMPACT AS HINTED
BY THE 00Z CNDN MODEL. EXPECT A DRYING TREND W-E ON SUN NGT WITH THE
ARRIVAL OF A HI PRES RDG.
EXTENDED RANGE...EXPECT A MORE SEASONABLY CHILLY PATTERN WITH NW
FLOW ALF ALLOWING FOR FREQUENT SHRTWV PASSAGES/POTENTIAL LES
EPISODES. MADE FEW CHGS TO ALL BLEND FCST NUMBERS.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
IR SATELLITE IMAGERY SHOWS STRATUS/FOG EXPANDING FROM ERN UPR MI
INTO CENTRAL UPR MI THIS EVENING AS LOW-LVL MOISTURE BCMS TRAPPED
UNDER STRENGTHENING INVERSION. KSAW HAS ALREADY GOTTEN INTO STRATUS
AND PATCHY FOG AND WOULD EXPECT THIS TO LINGER INTO THE LATE MORNING
AS SOUTHWEST WINDS PUSH MOISTURE BACK INTO THE REGION TONIGHT AND
INVERSION STRENGTHENS...EXPECT LOW CLOUDS TO REDEVELOP AND PUSH INTO
THE TAF SITES. GREATEST CHANCE OF LOW CLOUDS FORMING TONIGHT WILL BE
AT KSAW...BUT THERE SHOULD BE IFR/LOWER MVFR CLOUDS AT ALL SITES BY
MID MORNING ON FRIDAY. LLWS IS EXPECTED AGAIN TONIGHT AHEAD OF AN
APPROACHING SURFACE TROUGH THAT MOVES THROUGH ON FRIDAY.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
A SURFACE TROUGH STALLING OVER LAKE SUPERIOR TODAY WILL BRING A
DIMINISHING TREND TO THE WINDS THROUGH MUCH OF THE DAY. A LOW
DEVELOPING ALONG THE SURFACE TROUGH IN THE CENTRAL PLAINS
TODAY...WILL BEGIN TO MOVE NORTHEAST TONIGHT AND OVER CENTRAL UPPER
MICHIGAN ON SATURDAY. EXPECT INCREASING EAST TO NORTHEAST WINDS LATE
THIS AFTERNOON OVER THE WEST AND THE REST OVER THE AREA
TONIGHT...WITH GUSTS UP TO 30KTS OVER THE NORTH HALF OF THE LAKE
TONIGHT. AS THE LOW MOVES EAST ON SATURDAY NIGHT...NORTH GALES OF
35KTS ARE EXPECTED OVER WEST CENTRAL LAKE SUPERIOR. THE GALES SHOULD
SPREAD EAST ON SUNDAY AS WINDS SHIFT TO THE NORTHWEST...BEFORE
DIMINISHING BELOW 20KTS ON SUNDAY NIGHT AS HIGH PRESSURE MOVES OVER
LAKE SUPERIOR. A SURFACE TROUGH MOVING ACROSS LAKE SUPERIOR ON
MONDAY AFTERNOON AND EVENING WILL PROVIDE ANOTHER PERIOD OF STRONG
SOUTHWEST WINDS...WITH THE POTENTIAL OF NORTHWEST GALES TO 35KTS
BEHIND THE TROUGH MONDAY NIGHT AND TUESDAY MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY AFTERNOON FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
DISCUSSION...KC
AVIATION...VOSS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1230 AM EST FRI NOV 25 2011
.SYNOPSIS...
HIGH PRESSURE WITH DRY WEATHER CONTINUES THROUGH SATURDAY. MORE RAIN
SUNDAY WITH THE NEXT LOW PRESSURE SYSTEM. TURNING COLDER WITH RAIN
AND SNOW SHOWERS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...
HAVE MADE SOME SIGNIFICANT ADJUSTMENTS TO THE OVERNIGHT LOW
TEMPERATURES WITH THIS UPDATE. COOL SPOTS/VALLEYS HAVE DROPPED
QUICKLY...WHILE ELEVATED SITES IN THE WARMER BOUNDARY LAYER AIR
STILL REMAIN IN THE 40S IN SOME LOCATIONS. THIS INCLUDES SNOWSHOE.
LOCAL COOP MOS GUIDANCE IS BULLISH ON SOME OF THE LOWS GETTING
DOWN INTO THE MID 20S TONIGHT FOR PLACES LIKE NORTHEAST KENTUCKY
AND NORTHEAST OF PKB. SAME GUIDANCE ALSO SUGGESTS TEENS IN THE
GREENBRIER VALLEY OF POCAHONTAS COUNTY.
STILL ON BOARD WITH THE RUC AND THE LOW LEVEL STRATUS DECK
REDEVELOPING NEAR THE OHIO RIVER VALLEY INTO SOUTHEAST OHIO. EXTENT
OF THE OVERALL CLEARING CURRENTLY TAKING PLACE IS DECREASING
CONFIDENCE AT THE TIME OF THIS ISSUANCE.
PREVIOUS DISCUSSION...
NO SMELL OF TURKEY HERE. EVEN UNDER THE HIGH PRESSURE...THERE ARE
ISSUES. STRATUS UNDER THE TEMPERATURE INVERSION CONTINUES TO ERODE
FROM THE SOUTH. BY 22Z SUNSET...FIGURING THE STRATUS ONLY LEFT IN
OHIO.
WILL TRY TO REFORM...OR ADVECT...SOME OF THAT STRATUS 06Z TO 12Z
FRIDAY BACK IN SOUTHEAST OHIO AND MAYBE REACHING INTO NORTHWESTERN
WEST VIRGINIA INCLUDING THE PKB VCNTY. WITH WARMER BOUNDARY LAYER
TEMPERATURES...DO NOT THINK THE STRATUS WILL REFORM IN SOUTHERN WEST
VIRGINIA. SO CAN NOT RULE OUT SOME LOCAL VALLEY FOG IN THE DEEPER
VALLEYS THERE...UNDER THE CLEAR SKY 06Z TO 13Z.
HAVE NOT REEVALUATED TEMPERATURES...BUT DO NOT FORESEE ANY MAJOR
CHANGES THROUGH FRIDAY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
HIGH PRESSURE RIDGE ALOFT...AND A SURFACE HIGH PRESSURE WILL
PROVIDE CLEAR SKIES...AND DRY WEATHER CONDITIONS INTO THE DAY
SATURDAY.
THIS SCENARIO MEANS WARM AFTERNOON DUE TO HEATING...AND CHILLY
NIGHTS DUE TO RADIATIONAL COOLING AND STRONG SUBSIDENCE.
A LARGE DIURNAL RANGE IN TEMPERATURES WITH NEAR NORMAL LOWS BUT
ABOVE NORMAL HIGHS INTO THE 60S IS EXPECTED.
A COLD FRONT CROSS THE AREA EARLY SUNDAY. MODEL CONSENSUS SUGGEST
TEMPERATURES AT H850 REACHING MINUS 3 BY 12Z SUNDAY.
THEREFORE...EXPECT LIQUID PRECIPITATION WITH THE COLD FRONT ON
SUNDAY...PERHAPS MIXING WITH SNOW LATE OVER THE NORTHEAST
MOUNTAINS.
PEOPLE COMING BACK FROM THANKSGIVING WEEKEND COULD ENCOUNTER WET
ROADS ON SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
LOW CONFIDENCE CONTINUES IN THE LONG TERM PERIOD AS MODELS CONTINUE
TO DIFFER WITH THE HANDLING OF NEXT STORM SYSTEM...PROGGED TO MOVE
INTO THE REGION ON SUNDAY. 12Z RUN OF THE GFS INDICATES BULK OF
PRECIPITATION AND COLD FRONTAL BOUNDARY WILL BE ON THE WAY OUT OF
THE CWA BY THE START OF THE PERIOD...WITH COLDER AIR FILTERING IN
OVERNIGHT AS UPPER TROUGH CONTINUES TO PUSH EAST...WITH CAA PATTERN
FOR MONDAY. GFS THEN INDICATES A CLOSED LOW FORMING OVER THE
CAROLINAS...BEFORE TREKKING OFF TO THE EAST OVER THE ATLANTIC AS
SHORTWAVE RIDGING BUILDS INTO THE REGION. ECMWF CONTINUES TO
INDICATE A CLOSED LOW FORMING NEAR GULF STATES...BEFORE TREKKING
NORTHEAST TOWARDS THE REGION. THIS SCENARIO WOULD CREATE A PROLONGED
PERIOD OF WET WEATHER...AND WARMER TEMPERATURES THAT WOULD ALLOW FOR
THE BULK OF PRECIPITATION TO BE IN THE FORM OF RAIN. FOLLOWED HPC
THINKING...WHICH IS MORE PROGRESSIVE...AND FOLLOWS GFS MEAN SOLUN.
VERY TRICKY FORECAST IN TERMS OF PRECIPITATION TYPE ON SUNDAY
NIGHT/EARLY MONDAY. TEMPERATURES ARE EXPECTED TO BE COLD ENOUGH FOR
MUCH OF THE PRECIPITATION TO CHANGE OVER TO ALL SNOW...OR A
RAIN/SNOW MIX SUNDAY NIGHT...HOWEVER...DRIER AIR WILL ALSO BE
WORKING ITS WAY INTO UPPER AND MID LEVELS. AS A RESULT...REALLY NO
MOISTURE EXPECTED IN THE CRYSTAL GROWTH ZONE...AND IT IS
POSSIBLE...SOME OF THE PRECIPITATION MAY BE IN THE FORM OF A
FREEZING DRIZZLE...PARTICULARLY OVER THE LOWLAND COUNTIES. WITH THE
WARM GROUND TEMPERATURES HOWEVER...THIS WILL LIKELY MITIGATE ANY
MAJOR ISSUES TRAVEL WISE. FOR NOW...TO KEEP IN LINE WITH NEIGHBORS AND
DUE TO THE FACT THAT THE EVENT IS SEVERAL DAYS AWAY...KEPT
PRECIPITATION MAINLY AS SNOW OR A RAIN/SNOW MIX IN THE GRIDS. BEST
PLACE FOR ANY SNOWFALL ACCUMULATIONS SUNDAY NIGHT/MONDAY WILL BE
OVER THE NORTHERN MOUNTAIN ZONES...WHERE MODELS INDICATE AROUND 4
INCHES OR SO POSSIBLE. KEPT AMOUNTS GENERALLY LESS THAN THAT FOR
NOW...BUT WILL CONTINUE TO MONITOR FOR FUTURE FORECASTS.
PATTERN CONTINUES TO REMAIN PROGRESSIVE FOR THE REMAINDER OF THE
EXTENDED PERIOD WITH LOW FORECAST CONFIDENCE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
DENSE RIVER VALLEY FOG FORMING ACROSS THE REGION. AFTER THE FOG
LIFTS THIS MORNING...EXPECT VFR CONDITIONS FOR THE REMAINDER OF THE
PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF FOG FORMING AND DISSIPATING COULD
VARY.
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 FRI 11/25/11
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 M L L L L L L L M H H H
HTS CONSISTENCY M L L L L L L L M H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L L M H H H
PKB CONSISTENCY M M M L L M M L H H H H
CKB CONSISTENCY L L L L L L M L M H H H
AFTER 06Z SATURDAY...
IFR POSSIBLE IN RAIN AND SNOW SUNDAY INTO MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/ARJ/SL
NEAR TERM...KTB/26
SHORT TERM...ARJ
LONG TERM...SL
AVIATION...RPY
AREA FORECAST DISCUSSION
NWS NORMAN OK
1053 PM CST THU NOV 24 2011
.AVIATION...
/06Z TAFS/
IFR STRATUS DECK THAT HAS OVERSPREAD CENTRAL AND PARTS OF SW OK
WILL CONTINUE TO ADVANCE NORTH AND WEST OVERNIGHT AFFECTING ALL
TERMINALS WITH THE POSSIBLE EXCEPTION OF KGAG AND KWWR. AREAS OF
LIGHT FOG WILL ALSO OCCUR. LLWS EXPECTED DURING THE NIGHT AS THE
LOW LEVEL JET INCREASES. LOW CLOUDS SHOULD GRADUALLY BREAK UP DURING THE
MORNING. A COLD FRONT MOVING INTO NW OK FRIDAY EVENING WILL BRING
A CHANCE OF SHOWERS TO THE AREA... WITH GREATEST COVERAGE BEING
ACROSS NORTH CENTRAL OK.
&&
.PREV DISCUSSION... /ISSUED 816 PM CST THU NOV 24 2011/
UPDATE...
STRATUS HAS SPREAD NORTH/NORTHWEST QUICKLY THIS EVENING AND HRRR
SUGGESTS THAT THIS TREND WILL CONTINUE THROUGH THE NIGHT WITH
BROKEN TO OVERCAST SKIES LIKELY ENVELOPING THE EASTERN TWO-THIRDS
OR SO OF THE FORECAST AREA BY SUNRISE. HAVE MADE A MAJOR OVERHAUL
TO THE SKY GRIDS. ALTHOUGH THERE MAY BE SOME LOCATIONS WITH
RESTRICTED VISIBILITY... EXPECT WINDS TO REMAIN STRONG ENOUGH THAT
DO NOT EXPECT VERY MUCH DENSE FOG... ALTHOUGH THE HRRR DISAGREES
WITH THIS AND WILL CONTINUE TO WATCH TRENDS OVERNIGHT. HAVE ALSO
MADE BIG CHANGES TO THE HOURLY TEMPERATURE GRIDS DUE TO THE QUICK
DROP OF TEMPERATURES THIS EVENING AND USED THE RUC AS THE PRIMARY
SOURCE FOR THE TEMPERATURES. THIS ALSO REQUIRED SOME ADJUSTMENT TO
THE OVERNIGHT MINIMUM TEMPERATURE FORECAST ALTHOUGH IT APPEARS
THAT THESE CHANGES ARE MINOR IN MOST LOCATIONS.
PREV DISCUSSION... /ISSUED 600 PM CST THU NOV 24 2011/
AVIATION...
/00Z TAFS/
MAIN AVIATION ISSUE WILL OCCUR TONIGHT IN REGARDS TO THE
EVOLUTION AND MOVEMENT OF THE STRATUS DECK CURRENTLY IN SE OK.
BELIEVE IT WILL MOVE INTO PORTIONS OF CENTRAL AND SW OK... AND
WESTERN N-TX LATER TONIGHT... AND GIVEN MOST RECENT SATELLITE
TRENDS... IT MAY SPREAD FASTER THAN PREVIOUSLY EXPECTED. ALSO
MENTIONED LIKELIHOOD OF LLWS LATER TONIGHT IN SEVERAL LOCATIONS
AS THE LOW LEVEL JET STRENGTHENS. LOW CLOUDS EXPECTED TO SCATTER
OUT THURSDAY MORNING. MEANWHILE... A FEW SHOWERS MAY BEGIN TO
SPREAD INTO NW OK BY LATE IN THE DAY.
PREV DISCUSSION... /ISSUED 156 PM CST THU NOV 24 2011/
DISCUSSION...
CLOUDS CONTINUE TO ERODE IN SE PORTIONS OF THE FA THIS AFTERNOON.
HOWEVER... THEY ARE SLOW TO DO SO WHICH MEANS CLOUDS COULD LINGER
INTO THE EVENING. OTHERWISE... QUIET NIGHT TONIGHT WITH ONLY SOME
HIGH CLOUDS STREAMING INTO THE REGION AS UPPER TROUGH MOVING ACROSS
THE SW U.S. APPROACHES THE AREA. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE FRIDAY AS THE STORM SYSTEM APPROACHES WITH CHANCES
EXPANDING EAST AND RAIN BECOMING MORE WIDESPREAD FRIDAY NIGHT. HEAVY
RAIN IS NOT EXPECTED WITH THIS SYSTEM. THE UPPER SYSTEM WILL EXIT
THE REGION SATURDAY WITH RAIN CHANCES ENDING FOR THE FA BY AROUND
THE MIDDLE OF THE DAY SATURDAY. A COLD FRONT WILL ALSO MOVE ACROSS
THE REGION FRIDAY NIGHT INTO SATURDAY. STRONG NORTH WINDS ARE
EXPECTED BEHIND THE FRONT SATURDAY MAKING CONDITIONS FEEL MUCH
COOLER THAN THEY ARE.
TEMPERATURES WILL WARM SUNDAY INTO MONDAY BEFORE ANOTHER COLD FRONT
MOVES ACROSS THE REGION LATE MONDAY INTO TUESDAY. THIS FRONTAL
PASSAGE IS EXPECTED TO BE DRY BUT WILL BRING A COOLER AIRMASS TO THE
REGION. MODELS SHOW ANOTHER UPPER SYSTEM AND COLD FRONT AFFECTING
THE REGION TOWARDS THE END OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 46 64 45 51 / 0 20 70 10
HOBART OK 50 64 40 50 / 0 30 50 10
WICHITA FALLS TX 51 65 46 55 / 0 20 70 10
GAGE OK 47 65 36 45 / 0 40 40 0
PONCA CITY OK 46 65 43 49 / 0 20 70 10
DURANT OK 47 65 51 56 / 0 10 70 40
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
26/25/32
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
301 AM CST FRI NOV 25 2011
.SHORT TERM...TODAY THROUGH MONDAY
301 AM CST FRI NOV 25 2011
BIG CHANGES COMING OVER THE NEXT FEW DAYS AS RAIN STARTS UP
TONIGHT AHEAD OF A COLD FRONT WHICH WILL KNOCK TEMPERATURES DOWN
ON SATURDAY. BEYOND THIS...THERE IS MUCH UNCERTAINTY FOR SATURDAY
NIGHT INTO SUNDAY WITH WHETHER AN ACCUMULATING SNOW WILL OCCUR.
CURRENTLY...MILD CONDITIONS WERE OBSERVED ACROSS THE REGION DUE
TO GUSTY SOUTH TO SOUTHWEST WINDS AT THE SURFACE AHEAD OF A COLD
FRONT THAT EXTENDS FROM SOUTHWEST ONTARIO THROUGH NORTHERN
MINNESOTA ON INTO CENTRAL SOUTH DAKOTA. FURTHER ALOFT...GENERAL
SOUTHWEST FLOW AHEAD OF TROUGHING DUE TO A NORTHERN AND SOUTHERN
STREAM LOW WAS HELPING TO ADVECT MID TO HIGH LEVEL CLOUDS INTO THE
REGION. AS THE SOUTHERN STREAM TROUGH PROPAGATES EAST INTO THE
SOUTHERN PLAINS THIS MORNING...LOW LEVEL MOISTURE ADVECTION WILL
BE ON THE INCREASE AS A SURFACE LOW DEEPENS ACROSS THE NORTHERN
PLAINS. AS A RESULT...ANOTHER LOW LEVEL STRATUS DECK IS EXPECTED
TO DEVELOP NORTHWARD THIS MORNING FROM THE SOUTHERN PLAINS. THE
LATEST IR SCANS AT 8Z SHOWS THE LEADING EDGE OF THIS STRATUS NEAR
EMPORIA KANSAS...WHICH CORRELATES WELL TO THE 25.07Z RUC
950-900MB LAYER RH. THIS RUN OF THE RUC SHOWS THE HIGHER RH VALUES
INCREASING RAPIDLY THIS MORNING ACROSS THE SOUTHEASTERN HALF OF
IOWA TOWARD THE NORTHERN HALF OF LAKE MICHIGAN BY 18Z TODAY.
25.07Z RUC AND 25.00Z NAM/GFS SOUNDINGS FROM ACROSS THE REGION
SHOW THIS HIGHER RH BEING TRAPPED UNDER A STOUT 900-850MB
INVERSION AND THEREFORE HAVE GONE WITH A MORE PESSIMISTIC CLOUD
FORECAST TODAY. THIS CLOUD COVER WILL LIMIT HOW MUCH WARMING
CAN OCCUR INTO THE AFTERNOON WITH THE HIGHS LIKELY COMING THIS
MORNING.
AFTER THE STRATUS FILLS IN...THE NEXT QUESTION IS WHEN WILL THE
RAIN START UP TONIGHT. 25.00Z NAM AND GFS SOUNDINGS SHOW A DECENT
DRY LAYER CENTERED ON 800MB THAT WILL NEED TO BE OVERCOME FOR ANY
PRECIPITATION TO MAKE IT DOWN TO THE GROUND. BASED ON THESE
SOUNDINGS AND MID LEVEL QG FORCING FIELDS...IT APPEARS THAT THE
DEEP MOISTURE AND FORCING COMES TOGETHER LATER TONIGHT AHEAD OF
THE SURFACE COLD FRONT AND MID LEVEL TROUGH. THE THERMAL PROFILE
WILL BE WARM ENOUGH FOR THIS PRECIPITATION TO BE IN ALL LIQUID
FORM THROUGH SATURDAY MORNING BEFORE THE FRONT COMES THROUGH.
AFTER THE FRONT COMES THROUGH THE REGION SATURDAY MORNING INTO
EARLY SATURDAY AFTERNOON...UNCERTAINTY TAKES OVER WITH WHAT WILL
OCCUR SATURDAY NIGHT INTO SUNDAY. THE ONE THING THAT APPEARS TO
BE CERTAIN IS THAT COLDER AIR WILL ADVECT INTO THE REGION IN THE
LOW LEVELS BRINGING MUCH OF THE THERMAL PROFILE TO BELOW FREEZING
AND SUPPORTIVE OF SNOW BEING THE PRECIPITATION TYPE.
THE MAIN UNCERTAINTY LIES WITH THE DIFFERENCES BETWEEN THE US AND
NON-US MODEL SOLUTIONS WITH THE STRENGTH AND TRACK OF THE TROUGH.
BASED ON INPUT FROM HPC/S MODEL DIAGNOSTICS DESK...THE UNFAVORED
SOLUTION IS THE 25.00Z NAM/GFS AND 24.21Z SREF MEAN WHICH PRODUCE
A DEEPER...CLOSED OFF MID LEVEL LOW WHICH BRINGS THE DEFORMATION
AXIS THROUGH THE HEART OF THE FORECAST AREA. THESE SOLUTIONS WOULD
LIKELY LEAD TO AN ACCUMULATING SNOW ACROSS MUCH OF THE REGION.
THESE MODELS ALSO DEVELOPS A VERY TIGHT PRESSURE GRADIENT IN THE
LOW LEVEL COLD AIR ADVECTION POCKET ON THE SOUTHWEST SIDE OF THE
SURFACE LOW WHICH WOULD BRING GUSTS UP NEAR ADVISORY CRITERIA.
HOWEVER...AT THIS POINT THE FAVORED SOLUTION FOR SATURDAY NIGHT
INTO SUNDAY IS WITH THE 25.00Z ECMWF/UKMET/CANADIAN MODELS. THESE
FORMS OF GUIDANCE ALL SHOW A MUCH LESS AMPLIFIED...OPEN MID LEVEL
WAVE WITH HARDLY ANY SNOW COMING THROUGH SATURDAY NIGHT.
BASED ON THIS INPUT FROM HPC ...HAVE BACKED OFF ON THE PROBABILITY
FOR PRECIPITATION AND THE WIND GUSTS JUST A TAD ON SATURDAY NIGHT.
FOR ADDITIONAL INFORMATION ON THIS FAVORED TREND...PLEASE SEE THE
LATEST PMDHMD FROM HPC.
COLD AIR WILL REMAIN IN PLACE UNTIL MONDAY WHEN A BRIEF SHOT OF
LOW LEVEL WARM AIR ADVECTION COMES THROUGH THE REGION.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
301 AM CST FRI NOV 25 2011
NOT A WHOLE LOT OF CONFIDENCE GOING INTO THE EXTENDED PERIOD DUE
TO THE ISSUES THIS WEEKEND...BUT HAVE TRENDED TOWARD THE 25.00Z
ECMWF/GEM/UKMET FORECAST WHICH CUT OFF A MID LEVEL LOW ALONG THE
GULF COAST EARLY NEXT WEEK AND SLOWLY BRINGS IT TOWARD THE
NORTHEASTERN US INTO MID WEEK. THIS SETUP WILL KEEP THE REGION IN
A COOL NORTHWESTERLY FLOW ALOFT AND LIMIT ANY KIND OF WARMING
TRENDS. NOT MUCH IN THE WAY OF PRECIPITATION CHANCES EXCEPT FOR AN
OPEN MID LEVEL TROUGH THAT DIVES SOUTHEAST TOWARD THE GREAT LAKES
ON THURSDAY WHICH COULD BRING SOME PRECIPITATION WITH IT.
&&
.AVIATION...THROUGH 06Z SATURDAY
1135 PM CST THU NOV 24 2011
CONCERNS CONTINUE TO BE CENTERED ON LOW LEVEL WIND SHEAR IN THE
NEAR TERM AND THEN STRATUS AFTER 12Z FRIDAY. LOW LEVEL JET
CONTINUES QUITE STRONG WITH THE KARX VAD WIND PROFILE SHOWING 40
TO 50 KNOTS BETWEEN 2K-3K FEET. WITH SURFACE WINDS ONLY AROUND 10
KNOTS AT KLSE HAVE KEPT THE LOW LEVEL WIND SHEAR IN THE FORECAST
THROUGH 15Z FRIDAY AS THE JET THEN DIMINISHES. WINDS CONTINUE TO
GUST TO 25 KNOTS AT KRST AND EXPECT THESE TO CONTINUE THROUGH MUCH
OF THE NIGHT...BUT GRADIENT DOES RELAX AFTER 12Z AND DID DROP THE
GUSTS...BUT SUSTAINED WINDS WILL REMAIN ABOVE 12 KNOTS.
AS FOR THE STRATUS AND CEILINGS HEIGHTS. STRATUS WAS CURRENTLY OVER
OKLAHOMA ADVECTING NORTHWARD. 25.04Z RUC 1000MB-900MB RELATIVE
HUMIDITY PROG HAS A DECENT HANDLE ON THIS MOISTURE...BUT IS A
LITTLE TO FAR NORTH WITH IT INITIALLY. BOTH THE RUC AND THE 25.00Z
NAM BOTH SHOW THIS MOISTURE ADVECTING NORTHWARD...BUT NOT ARRIVING
UNTIL THE 13Z-15Z TIME FRAME. WITH CONSISTENT SIGNAL DID INCLUDE A
BROKEN CEILING AT BOTH TAF SITES...BUT FOR NOW KEPT THEM IN THE
010K-015K FOOT RANGE. NEXT SHIFT SHOULD HAVE A BETTER HANDLE ON
TIMING AND EXTENT OF THESE CLOUDS.
WITH THE COLD FRONT PUSHING CLOSER TO THE AREA BETWEEN 00Z-06Z
SATURDAY...DID MENTION VCSH AT BOTH SITES AFTER 03Z WITH A
CONTINUATION OF THE MVFR CEILINGS.
&&
.CLIMATE...FOR TODAY
301 AM CST FRI NOV 25 2011
RECORD HIGHEST LOWS MAY BE BROKEN TODAY AT BOTH ROCHESTER AND LA
CROSSE WITH TEMPERATURES THIS MORNING FAIRLY MILD IN THE UPPER 40S
TO AROUND 50. THE RECORD HIGHEST LOW TEMPERATURE FOR ROCHESTER
TODAY IS 37 FROM 1915. THE RECORD HIGHEST LOW TEMPERATURE FOR LA
CROSSE TODAY IS 42 IN 1998. FORECAST TEMPERATURES AT MIDNIGHT
TONIGHT ARE EXPECTED TO BE ABOVE THESE VALUES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
301 AM CST FRI NOV 25 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
CLIMATE...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 PM CST THU NOV 24 2011
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
236 PM CST THU NOV 24 2011
MAIN FORECAST CONCERNS THIS PACKAGE...RAIN CHANCES FRI NIGHT/SAT...
WINDS SAT...RAIN/SNOW CHANCES SAT NIGHT...TEMPERATURES THRU THE
PERIOD.
DATA ANALYSIS AT 18Z HAD TIGHTER PRESSURE GRADIENT BETWEEN HIGH
PRESSURE OVER THE SOUTHEAST CONUS AND LOW PRESSURE EAST OF LK
WINNIPEG OVER THE AREA. BRISK SOUTH WINDS ACROSS MUCH OF MN/IA/WI AT
MID-DAY. THESE WINDS...COMBINED WITH DIURNAL WARMING AND SOUTHWEST-
WEST FLOW IN THE 925-700MB LAYERS HELPING TO ERODE/ADVECT THE LOW
STRATUS CLOUDS EAST AND OUT OF THE FCST AREA. TEMPS RESPONDING TO
THE WARM ADVECTION/MOSTLY SUNNY SKIES WITH NOONTIME READINGS IN THE
MID 40S TO MID 60S FROM NORTHEAST WI TO SOUTHWEST IA...SOME 10-20F
ABOVE NORMAL AND NEAR RECORD HIGHS AT SOME LOCATIONS ON THIS
THANKSGIVING DAY.
24.12Z MODELS LOOK TO HAVE INITIALIZED WELL AND OFFER RATHER SIMILAR
SOLUTIONS FOR TONIGHT INTO SAT. MODELS GRADUALLY CONVERGING ON A
COMMON/TIGHTER CONSENSUS SOLUTION WITH THE TROUGH/LOW TO MOVE ACROSS
THE REGION FRI NIGHT THRU SAT NIGHT. DPROG/DT OF 500MB HGTS AT
24.12Z SHOWED MODEL RUNS OF 22.12Z AND 23.12Z VERIFIED QUITE WELL
ACROSS NOAM/EASTERN PAC WITH BETTER RUN-TO-RUN CONSISTENCY BY ECMWF.
TREND IS TOWARD A COMPROMISE OF THE EARLIER RUNS. MODELS CONTINUE TO
CONVERGE TOWARD A COMMON SOLUTION TONIGHT THRU SAT AS THE TROUGH/
ENERGY MOVES FROM NEAR THE WEST COAST TO THE WESTERN PLAINS BY 00Z
SAT THEN TO THE MID/UPPER MS VALLEY BY 00Z SUN. TREND GENERALLY
FAVORS THE SLOWER OF THE EARLIER RUNS WITH A COMPROMISE ON THE
STRENGTH OF THE TROUGH. DIFFERENCES REMAIN BETWEEN THE MODELS FOR
SAT NIGHT INTO SUN NIGHT WITH A MORE CONSOLIDATED LOW/TROUGH OVER
THE CENTRAL GREAT LAKES /GFS/NAM/ VS. A MORE NORTHERN/SOUTHERN
STREAM...OPEN TROUGH SPLIT OF THE ENERGY /ECMWF/GEM/UKMET/. GFS
ENSEMBLE MEAN SPLITS THE DIFFERENCE OF THE 2 GROUPS SAT NIGHT/SUN.
ECMWF LOOKS TO HAVE SLIGHTLY BETTER RUN-TO-RUN CONSISTENCY IN THE
LATER PART OF THE SHORT-TERM PERIOD. CHECK OF OBS VS. MODEL DATA AT
18Z SHOWED MODELS ALL REASONABLE WITH THE SFC MASS FIELDS OVER THE
CENTRAL CONUS. PER WV IMAGERY...ALL APPEARED REASONABLE WITH THE
SHORTWAVE DETAILS OVER NOAM/EASTERN PAC. THUS AGAIN NO CLEAR
DETERMINISTIC MODEL FAVORITE. WITH THE TRENDS TOWARD A COMPROMISE
SOLUTION...AT LEAST THRU 60HRS...FAVORED THE MODEL/ENSEMBLE
COMPROMISE SOLUTION. GIVEN THE CONTINUED DETAIL DIFFERENCES...SHORT-
TERM FCST CONFIDENCE AVERAGE AT BEST THIS CYCLE.
IN THE SHORT TERM...FIRST CONCERN IS RETURN OF MOISTURE IN 950-900MB
LAYER TONIGHT AND IF IT WILL MANIFEST AS ANOTHER LOW STRATUS DECK
OR NOT. SEE AVIATION DISCUSSION BELOW FOR MORE DETAILS ON POTENTIAL
LOW CLOUDS/BR TONIGHT AS THE LOWER LEVEL MOISTURE RETURNS. DID SHOW
INCREASING CLOUDS IN THE GRIDS LATER TONIGHT AS MOISTURE/BROAD LIFT
ABOVE 500MB AHEAD OF THE TROUGH ADVANCING THRU THE ROCKIES INCREASE
OVER THE AREA. BRISK WINDS TONIGHT AND THESE CLOUDS TO MAKE FOR A
SEASONABLY MILD NIGHT ACROSS THE AREA TONIGHT...WITH LOWS ABOVE THE
NORMAL HIGHS FOR THE DATE. MOISTURE/LIFT CONTINUE TO INCREASE OVER
THE AREA FRI WITH THICKENING CLOUDS. QUESTION REMAINS WILL A SMALL
-RA CHANCE BE NEEDED ACROSS THE SOUTH END OF THE FCST AREA LATE IN
THE AFTERNOON. MODELS MAINTAIN A DRY LAYER BETWEEN 850-650MB OVER
THE SOUTH END OF THE FCST AREA FRI AFTERNOON...WITH MODEST LIFT AT
BEST AT OR ABOVE 500MB. WILL MAINTAIN THE DRY FRI AFTERNOON FCST FOR
NOW. MOISTURE/850-500MB THERMO-DYNAMIC FORCING/LIFT INCREASE QUICKLY
FRI EVENING...MAXIMIZING OVER THE FCST AREA LATE FRI NIGHT INTO
EARLY SAT MORNING. THIS WITH INCREASING 500-300MB PV ADVECTION AND
300MB AGEOSTROPHIC FLOW/DIVERGENCE IN RIGHT ENTRANCE REGION OF A
110KT JET AHEAD OF THE TROUGH AXIS. PW VALUES INCREASE INTO THE 0.75
TO 1 INCH RANGE OVER THE SOUTHEAST 3/4 OF THE FCST AREA AS WELL BY
12Z SAT. THUS RAISED RAIN CHANCE THRU FRI NIGHT...INTO THE 60-85
PERCENT RANGE AFTER MIDNIGHT. RAISED RAIN CHANCES SAT MORNING INTO
THE 60-80 PERCENT RANGE OVER THE EAST HALF OF THE FCST AREA. LEFT
RAIN CHANCES IN THE 30-50 PERCENT RANGE OVER THE WEST THIRD OF THE
FCST AREA SAT MORNING AS BETTER CONSENSUS FOR THE COLD FRONT AND
925-850MB TROUGH AXIS TO BE MOVING EAST OF THE MS RIVER DURING THE
MORNING. DRIER AIR AND COLD ADVECTION/SUBSIDENCE TO BE SPREADING
INTO THE AREA BEHIND THE SFC-850MB FRONT. QUESTION FOR SAT
AFTERNOON BECOMES HOW QUICKLY WILL THE COLUMN COOL ENOUGH FOR ANY
PRECIP TO MIX WITH/CHANGE TO SNOW. NAM MOST ROBUST BRINGING IN THE
COLD AIR. TEMPS DO FALL DURING THE DAY SAT IN THE STRONG POST
FRONTAL COLD ADVECTION BUT MODEL CONSENSUS KEEPS THE BOUNDARY LAYER
TEMPS DURING THE AFTERNOON IN THE UPPER 30S/AROUND 40. THIS A BIT
WARM FOR A COMPLETE CHANGE TO -SN OR ACCUMULATIONS...GIVEN BULK OF
FORCING/LIFT IS NORTH/EAST OF THE AREA AND PRECIP RATES EXPECTED TO
BE ON THE LIGHT SIDE BY SAT AFTERNOON. CONTINUED A -RA/-SN MIX FOR
MUCH OF THE AREA SAT AFTERNOON. STRONGEST OF SFC-850MB COLD
ADVECTION MOVES ACROSS THE AREA SAT MORNING WHILE STRONGEST OF SFC-
925MB GRADIENT WINDS MOVE ACROSS THE AREA CENTERED ON SAT NIGHT.
STRONG/GUSTY NORTHWEST WINDS TO SPREAD ACROSS THE AREA SAT/SAT NIGHT
BUT AT THIS TIME LOOK TO REMAIN BELOW ADVISORY CRITERIA. DID
INCREASE WINDS SAT NIGHT INTO SUN WITH GRADIENT REMAINING TIGHT AND
CONTINUING LOW LEVEL COLD ADVECTION OVER THE AREA. BOUNDARY LAYER
COOLS ENOUGH FOR ALL SNOW SAT EVENING. NAM/GFS SHOWING MORE WRAP
AROUND/DEFORMATION BAND PRECIP ON THE BACK SIDE OF THE SYSTEM WITH A
500MB LOW OVER EASTERN WI/LK MI WHILE MORE OPEN/POSITIVE TILT WAVE
SOLUTION OF ECMWF/GEM/UKMET MUCH WEAKER WITH FORCING/LIFT/PRECIP
PRODUCTION BEHIND THE TROUGH AXIS SAT NIGHT/SUN MORNING. LEFT BULK
OF -SN/-RA CHANCES SAT NIGHT IN THE 20-50 PERCENT RANGE FOR NOW...
ONLY CARRYING LIKELY ALONG/NORTH OF HIGHWAY 29 ACROSS CENTRAL WI.
DID LINGER A 20 PERCENT -SN CHANCE OVER THE EAST HALF OF THE FCST
AREA SUN MORNING TO HONOR NAM/GFS SOLUTIONS. HIGH PRESSURE/SHORTWAVE
RIDGING ALOFT BUILD IN FOR LATER SUN/SUN NIGHT.
FAVORED A BLEND OF THE NUMERICAL TEMP GUIDANCE FOR MOST LOWS/HIGHS
TONIGHT THRU SUN NIGHT. DID FAVOR WARMER OF GUIDANCE LOWS TONIGHT
WITH BRISK SOUTH WINDS AND INCREASE OF HIGH CLOUDS AFTER MIDNIGHT.
CONTINUED THE TREND OF HIGHS SAT AROUND 15Z THEN FALLING TEMPS
BEHIND THE COLD FRONT THE REST OF THE DAY. WITH SFC RIDGE AXIS OVER
THE AREA SUN NIGHT FAVORED COOLER OF GUIDANCE LOWS.
.LONG TERM...MONDAY THROUGH THURSDAY
236 PM CST THU NOV 24 2011
24.00Z MEDIUM RANGE MODELS SHOW QUITE A BIT OF VARIABILITY ALREADY
MONDAY WITH THE PROGRESSIVENESS OF THE TROUGHING OVER THE EASTERN
CONUS. RUN-TO-RUN CONSISTENCY LEAVES QUITE A BIT TO BE DESIRED TOO.
MODELS BETTER/MORE CONSISTENT WITH THE NEXT TROUGH DROPPING INTO
THE NORTHERN PLAINS BUT TREND IS A BIT FLATTER/FASTER WITH THIS
FEATURE. MODELS REMAIN FASTER/FLATTER WITH THIS FEATURE TUE WITH A
TREND TOWARD MORE ZONAL FLOW OVER THE NORTH-CENTRAL AND NORTHWEST
CONUS. STILL PLENTY OF DIFFERENCES WITH EAST/SOUTHEAST CONUS LOW.
GFS/ECMWF SOLUTIONS DIVERGE FOR WED WITH TIMING ISSUES OF A
STRONGER SHORTWAVE THRU BROAD NORTHWEST FLOW OVER WESTERN NOAM.
SOLUTIONS TREND MORE SIMILAR WITH A SHORTWAVE TROUGH MOVING ACROSS
THE WESTERN GREAT LAKES THU. RUN-TO-RUN CONSISTENCY REMAINS BELOW
AVERAGE WED/THU...TIED TO GLOBAL FLOW FORCING MECHANISMS AS
DISCUSSED BY MID SHIFT FORECASTER. UNTIL THIS SETTLES DOWN...RUN-TO-
RUN CONSISTENCY BEYOND ABOUT DAY 5 CAN BE EXPECTED TO REMAIN BELOW
AVERAGE. LONG-TERM FCST CONFIDENCE AGAIN BELOW AVERAGE WITH ALL THE
BETWEEN MODEL AND RUN-TO-RUN VARIABILITY...THUS WILL LEAVE DAY 4-7
GRIDS CLOSE TO A THE MODEL/ENSEMBLE CONSENSUS. WITH A DRIER WEST TO
NORTHWEST FLOW ALOFT AND MAIN SHORTWAVE ENERGY LOOKING TO PASS NORTH
OF THE AREA...DAYS 4-7 TRENDING TO BE A MOSTLY DRY PERIOD.
REASONABLE MODEL CONSENSUS FOR A FRONT TO PUSH ACROSS THE AREA MON
BUT MOISTURE LIMITED AND SFC FRONT PASSES WELL AHEAD OF THE MID
LEVEL TROUGH. CONSENSUS FOR SFC HIGH PRESSURE TO BUILD OVER THE
REGION FOR TUE. MAIN SHORTWAVE ENERGY WED OR THU /DEPENDS ON WHICH
MODEL WOULD BE MORE CORRECT WITH TIMING/ PASSES NORTH OF THE AREA
WITH ANOTHER FRONT TO PUSH ACROSS THE UPPER MIDWEST ONE OF THE DAYS.
24.12Z GFS/ECMWF PUSH A STRONGER TROUGH/FRONT TOWARD/ACROSS THE
REGION THU...WITH A SMALL -RA/-SN CHANCE THAT DAY REASONABLE FOR
NOW. TEMPERATURES FOR DAYS 4-7 LOOKING TO BE NEAR/A BIT ABOVE NORMAL
AND THIS WELL TRENDED WITH THE MODEL CONSENSUS GRIDS.
&&
.AVIATION...THROUGH 06Z SATURDAY
1135 PM CST THU NOV 24 2011
CONCERNS CONTINUE TO BE CENTERED ON LOW LEVEL WIND SHEAR IN THE
NEAR TERM AND THEN STRATUS AFTER 12Z FRIDAY. LOW LEVEL JET
CONTINUES QUITE STRONG WITH THE KARX VAD WIND PROFILE SHOWING 40
TO 50 KNOTS BETWEEN 2K-3K FEET. WITH SURFACE WINDS ONLY AROUND 10
KNOTS AT KLSE HAVE KEPT THE LOW LEVEL WIND SHEAR IN THE FORECAST
THROUGH 15Z FRIDAY AS THE JET THEN DIMINISHES. WINDS CONTINUE TO
GUST TO 25 KNOTS AT KRST AND EXPECT THESE TO CONTINUE THROUGH MUCH
OF THE NIGHT...BUT GRADIENT DOES RELAX AFTER 12Z AND DID DROP THE
GUSTS...BUT SUSTAINED WINDS WILL REMAIN ABOVE 12 KNOTS.
AS FOR THE STRATUS AND CEILINGS HEIGHTS. STRATUS WAS CURRENTLY OVER
OKLAHOMA ADVECTING NORTHWARD. 25.04Z RUC 1000MB-900MB RELATIVE
HUMIDITY PROG HAS A DECENT HANDLE ON THIS MOISTURE...BUT IS A
LITTLE TO FAR NORTH WITH IT INITIALLY. BOTH THE RUC AND THE 25.00Z
NAM BOTH SHOW THIS MOISTURE ADVECTING NORTHWARD...BUT NOT ARRIVING
UNTIL THE 13Z-15Z TIME FRAME. WITH CONSISTENT SIGNAL DID INCLUDE A
BROKEN CEILING AT BOTH TAF SITES...BUT FOR NOW KEPT THEM IN THE
010K-015K FOOT RANGE. NEXT SHIFT SHOULD HAVE A BETTER HANDLE ON
TIMING AND EXTENT OF THESE CLOUDS.
WITH THE COLD FRONT PUSHING CLOSER TO THE AREA BETWEEN 00Z-06Z
SATURDAY...DID MENTION VCSH AT BOTH SITES AFTER 03Z WITH A
CONTINUATION OF THE MVFR CEILINGS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
236 PM CST THU NOV 24 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DES MOINES IA
552 AM CST FRI NOV 25 2011
...UPDATED FOR 12Z AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
STRATUS FIELD IS LIFTING THROUGH EASTERN KS AS LOW LEVEL MOISTURE
CONTINUES TO ADVECT NORTHWARD TOWARD IOWA. THE MOISTURE IS CENTERED
NEAR 950 MB. THE LATEST RUC 950 MB CONDENSATION PRESSURE DEFICITS
ARE HANDLING THE STRATUS PLACEMENT WELL AND SUGGESTS IT WILL SPREAD
NORTHEAST OVER MUCH OF CNTRL IA THIS MORNING. CIRRUS WILL ALSO BE
THICKENING OVER THE STATE TODAY AND IN COMBINATION WITH THE
STRATUS...WILL RESULT IN MOSTLY CLOUDY CONDITIONS. THIS WILL HAVE AN
IMPACT ON HIGH TEMPERATURES. READINGS AT 3 AM REMAIN QUITE MILD IN
THE MID TO UPPER 40S. ANY SUNSHINE THIS MORNING COULD QUICKLY PUSH
READINGS WELL INTO THE 50S. EXPECT CLOUDS TO BECOME PREVALENT BY MID
MORNING AND WILL LIMIT TEMPERATURES...THEREFORE HAVE TEMPERED HIGHS
FOR TODAY BACK A FEW DEGREES AND MORE INTO THE MID TO UPPER 50S.
THIS WILL BE TOO WARM IF THE STRATUS LINGERS ALL DAY.
THE INITIAL SHORT WAVE WILL REACH WESTERN IA BY THIS AFTERNOON WITH
INCREASING QG FORCING AND THE MID LEVEL DRY AIR SLOWLY ERODING AS
EVAPORATING PRECIPITATION FALLS INTO THIS LAYER. POSSIBLE BY VERY
LATE AFTERNOON THAT A FEW SPRINKLES OR LIGHT RAIN COULD REACH THE
SFC OVER THE FAR WEST CENTRAL AND SOUTHWEST. THEREFORE HAVE ADDED
LOW POPS.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
FORECAST PROBLEM IN THE LONG TERM CONTINUES TO BE THE UPPER TROUGH
MOVING THROUGH THE UPPER MIDWEST THIS WEEKEND. A NORTHERN STREAM
SHORTWAVE WAS MOVING EAST THROUGH THE NORTHERN ROCKIES THIS MORNING
WHILE A WEAKER SOUTHERN STREAM WAVE WAS MOVING THROUGH THE DESERT
SOUTHWEST. THE NORTHERN SYSTEM IS FORECAST TO MOVE SOUTHEAST INTO
THE CENTRAL UNITED STATES AND DEEPEN BY SATURDAY. THE 00Z GFS/NAM
PHASE THE TWO WAVES IN THE CENTRAL STATE AND SIGNIFICANTLY DEEPEN
THE TROUGH INTO A CLOSED 500 MB LOW. THE 00Z ECMWF REMAINS
CONSISTENT WITH IT/S PREVIOUS RUN KEEPING THE SHORT WAVE ENERGY
SEPARATE. AS A RESULT...THE NORTHERN SHORTWAVE REMAINS A POSITIVE
TILTED OPEN WAVE. THE GFS/NAM SOLUTIONS HAVE A MUCH DEEPER SURFACE
LOW WHICH DEVELOPS NORTHEAST OF CENTRAL IOWA. WITH THE DEEPER
SYSTEM...THE WIND FIELDS ARE STRONG. IF THE GFS/NAM SOLUTIONS
VERIFY...AT A MINIMUM CENTRAL IOWA SHOULD HAVE A DECENT WIND EVENT
AND SOME LIGHT SNOW DUE TO THE STRONGER FORCING. IF THE WEAKER
LOOKING ECMWF VERIFIES...IT WOULD BE WINDY...BUT PROBABLY BELOW
ADVISORY CRITERIA AND LESS SNOW CHANCES. BASED THE FORECAST ON A
COMPROMISE BETWEEN THESE VARIED SOLUTIONS. NO HEADLINES FOR WIND AT
THIS POINT...BUT WILL MENTION WINDY CONDITIONS IN THE HWO. WILL
ALSO MENTION THE POSSIBILITY OF LIGHT SNOW...ESPECIALLY NORTH...BUT
ACCUMULATIONS SHOULD BE LIGHT.
MOISTURE STEAMING NORTHEAST AHEAD OF THE FRONT TONIGHT ALONG WITH A
LARGE AREA OF UPWARD FORCING AHEAD OF THE UPPER TROUGH SUPPORTS HIGH
POPS FOR RAIN TONIGHT.
ANOTHER COLD FRONT SHOULD MOVE THROUGH THE STATE LATE MONDAY. LACK
OF SIGNIFICANT FORCING AND MOISTURE SHOULD KEEP IT DRY. THE 00Z
ECMWF IS ADVERTISING A STRONGER COLD FRONT LATE NEXT WEEK.
CONFIDENCE ON THE TIMING OF THE FRONTS IS LOW DUE TO MODEL
DIFFERENCES NEXT WEEK BETWEEN THE ECMWF AND THE OPERATIONAL GFS.
&&
.AVIATION...25/12Z
MVFR TO IFR STRATUS HAS BEEN RAPIDLY ADVANCING NORTHEAST THROUGH
EASTERN KANSAS OVERNIGHT. THIS BAND SHOULD OVERSPREAD ALL SITES
THROUGH 15Z. SOME UNCERTAINTY IF THE STRATUS WILL MAINTAIN THROUGH
THE AFTERNOON ESPECIALLY OVER THE WRN AND SRN SITES. HAVE OPTED TO
HOLD IT THROUGH THE DAY. EVEN IF IT BREAKS...THE STRATUS SHOULD
REDEVELOP EARLY THIS EVENING. RAIN SHOULD DEVELOP OVERNIGHT AS WELL.
A COLD FRONT WILL ARRIVE THROUGH THE WESTERN SITES AFTER 09Z
BRINGING GUSTY NORTHWEST WINDS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DONAVON
LONG TERM...JOHNSON
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
652 AM EST FRI NOV 25 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT UPR
RDGING IN PLACE OVER NAMERICA DOWNSTREAM OF TROFFING OVER THE PAC NW
AND WRN CAN. CLOSER TO THE SFC...THE UPR GRT LKS ARE DOMINATED BY A
STRONG SW FLOW BTWN HI PRES IN THE MID ATLANTIC STATES AND LO PRES
OVER NRN ONTARIO. GRAND MARAIS IN ALGER COUNTY REPORTED SW WIND
GUSTS UP TO 37 MPH AT 0330Z. THE 00Z INL AND MPX RAOBS ARE QUITE DRY
/IN FACT...THE 00Z H7 DEWPT DEPRESSION AT ABERDEEN SDAKOTA WAS
42C/...SO NOTHING BUT HI CLDS ARE PRESENT ALONG AND AHEAD OF
ATTENDANT COLD FNT EXTENDING FM THE ONTARIO LO THRU NW MN INTO
NDAKOTA. MORE EXTENSIVE LO CLDS FOLLOW THE FROPA OVER NW NDAKOTA AND
SCNTRL CAN WITH SHALLOW COLD AIR INFUSION. OVER THE E HALF OF THE
CWA...LLVL MSTR DEPICTED ON THE 00Z GRB RAOB BLO SHARP INVRN BASE
NEAR H95 HAS RESULTED IN EXTENSIVE LO CLD. OTRW TEMPS ARE WELL ABV
NORMAL FOR THE SEASON...WITH 00Z H85 TEMPS RANGING FM 13C AT GRB AND
INL TO 15C AT MPX. SFC TEPS ARE STILL WELL INTO THE 40S AT MANY
PLACES EARLY THIS MRNG...10 TO 15 DEGREES ABV THE NORMAL HI TEMPS
FOR THE DATE. WELL TO THE W... WV IMAGERY INDICATES A STRONGER
SHRTWV IS APRCHG THE PAC NW...WHERE 12Z-24Z H3 FALLS UP TO 100M
OCCURRED.
&&
.DISCUSSION...
MAIN FCST CONCERNS SHIFT FM LO CLDS/WELL ABV NORMAL TEMPS TDAY TO
PCPN CHCS TNGT THRU THE WEEKEND.
TDAY...SFC HI PRES OVER THE MID ATLANTIC IS PROGGED TO DRIFT OFF THE
SE COAST WHILE LO PRES NOW OVER NRN ONTARIO WL DRIFT ACRS QUEBEC...
DRAGGING ATTENDANT COLD FNT INTO THE CWA DURING THE AFTN. ALTHOUGH
SFC TEMPS WL BE HELD DOWN ESPECIALLY OVER THE NW WITH THE ARRIVAL OF
LLVL COLDER AIR/ARRIVAL OF MORE LO CLDS BEHIND THE FROPA...READINGS
WL STILL BE WELL ABV NORMAL...ESPECIALLY OVER THE SCNTRL WHERE THE
LO CLDS ARE MORE LIKELY TO BREAK UP. THE SW FLOW OFF LK MI THRU THE
DAY AND LO SUN ANGLE WL LIKELY RESULT IN A PERSISTENCE OF THE LO CLD
OVER THE E EVEN THOUGH THE STRONGER SW WINDS OBSVD EARLY THIS MRNG
WL DIMINISH QUICKLY AS THE PRES GRADIENT SLACKENS. ALTHOUGH SOME
MODELS GENERATE LGT PCPN OVER THE CWA WITH THE COLD FROPA...PREFER
THE DRY NAM GIVEN THE EXCESSIVE MID LVL DRYNESS OBSVD UPSTREAM.
TNGT...STRONGER SHRTWV NOW MOVING INTO THE PAC NW IS FCST TO DEEPEN
UPR TROF IN THE PLAINS...WITH SFC LO PRES DVLPG OVER NW WI ON
STALLED FNT THAT WL REMAIN ACRS THE CWA. ALTHOUGH LINGERING MID LVL
DRY AIR WL LIMIT PCPN CHCS IN THE EVNG...EXPANDING DEEP LYR QVECTOR
CNVGC/UPR DVGC/SHARPENING H85-7 FGEN ASSOCIATED WITH APRCHG SHRTWV/
EXIT REGION OF ACCOMPANYING 120KT H3 JET MAX WL INCRS RA CHCS
ESPECIALLY OVER THE SW HALF LATER. TENDED TOWARD THE SOMEWHAT WETTER
00Z GFS/12Z ECMWF GIVEN APPARENT STRENGTH OF SHRTWV NOW APRCHG THE
PAC NW.
SAT...MODEL DISCREPANCIES BECOME MORE PRONOUNCED WITH THE HANDLING
OF THE DVLPG LO...SO CONFIDENCE IN THE FCST WL DIMINISH. GIVEN
APPARENT STRENGHT OF INCOMING SHRTWV AS MENTIONED ABOVE...TENDED
TOWARD THE DEEPER 00Z NAM/GFS SCENARIOS THAT SHOW CUTOFF H5 LO
FORMING SOMEWHERE OVER THE UPR MS RIVER VALLEY/UPR MIDWEST.
HOWEVER...NCEP PREFERENCE FOR THE WEAKER SOLNS SHOWN BY THE 12Z
ECMWF AND 00Z CNDN LOWER CONFIDENCE FURTHER. FORTUNATELY...THERE IS
RELATIVELY LTL DIFFERENCE IN THE SFC LO PLACEMENT AMONG THE VARIOUS
MODELS DESPITE THE DIFFERENCES IN INTENSITY. MODELS SHOW SFC LO
MOVING TO NEAR MQT BY 00Z SUN. ALTHOUGH DRY SLOTTING TO THE E OF THE
H5 LO WL LIKELY RESULT IN A DIMINISHING TREND OF THE PCPN OVER
MAINLY THE CNTRL AND E...EXPECT HEAVIER PCPN TO LINGER OVER THE W FM
IWD-CMX THRU THE DAY CLOSER TO THE TRACK OF THE ACCOMPANYING H85 LO.
PER GFS FCST WBLB ZERO HGT FCST TO FALL NEAR 1K FT AGL BY 00Z
SUN...EXPECT ENUF COLD AIR TO ARRIVE LATE IN THE DAY TO RESULT IN AT
LEAST A MIX OF RA/SN NEAR IWD UNDER THE SHARPER CYC NLY FLOW.
SAT NGT THRU SUN...VARIOUS MODELS SHOW SFC LO DRIFTING SLOWLY TO THE
NE TO SSE OF JAMES BAY BY LATE IN THE DAY SUN. THE NAM BECOMES A
PARTICULAR OUTLIER SHOWING THE LO LINGERING NEAR UPR MI...SO
REJECTED THIS FCST. THE OTHER PREFERRED MODELS SUG PCPN WITHIN COMMA
HEAD MSTR UNDER SHARPER NNW CYC FLOW/H85 THERMAL TROFFING WL IMPACT
MAINLY THE NW HALF AND SLOWLY CHG TO SN AS COLDER AIR MOVES OVHD...
WITH BOTH THE 00Z GFS/12Z ECMWF INDICATING H85 TEMPS FALLING TO ARND
-9C...LO ENUF FOR LK EFFECT PCPN CONSIDERING LK SUP TEMPS ARND 5C.
HOWEVER...EVEN THE DEEPER GFS SUGS SN GROWTH MICROPHYSICS WL NOT BE
VERY FVRBL GIVEN FCST WEAK UVV IN THE DENDRITIC SN GROWTH ZN. EVEN
SO...SOME LO END ADVY SN AMNTS MAY BE PSBL OVER THE W WITH LK
ENHANCEMENT AS THE SN SHOULD BE WET AND HEAVY. THE NEW 00Z ECMWF
INDICATES GOOD CONTINUITY WITH THE 12Z RUN...BUT SHOWS QUICKER
DRYING ON SUN WITH A WEAKER CYC FLOW/FASTER EXIT THAN INDICATED BY
THE DEEPER GFS. TENDED TOWARD HIER POPS OVER THE W TO THE HURON MTNS
WHERE THE UPSLOPE NNW FLOW WOULD HAVE A MORE SGNFT IMPACT AS HINTED
BY THE 00Z CNDN MODEL. EXPECT A DRYING TREND W-E ON SUN NGT WITH THE
ARRIVAL OF A HI PRES RDG.
EXTENDED RANGE...EXPECT A MORE SEASONABLY CHILLY PATTERN WITH NW
FLOW ALF ALLOWING FOR FREQUENT SHRTWV PASSAGES/POTENTIAL LES
EPISODES. MADE FEW CHGS TO ALL BLEND FCST NUMBERS.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
ANOTHER DIFFICULT TAF FORECAST...AS LOW CLOUDS HAVE SPREAD OVER
CENTRAL AND EASTERN UPPER MICHIGAN. WITH THE LIGHT UPSLOPE FLOW AT
KSAW...EXPECT THE VLIFR CIGS/VSBYS TO CONTINUE THROUGH THE MORNING.
DIURNAL TRENDS WILL TRY TO RAISE CIGS...BUT WITH WINDS WEAKENING
THROUGH THE DAY...HAVE A TOUGH TIME BELIEVING THEY WILL EXIT LIKE
YESTERDAY. AS FOR KIWD/KCMX...EXPECT JUST HIGH CLOUDS TO AFFECT BOTH
SITES THIS MORNING. LIMITED CONFIDENCE ON MVFR CIGS MOVING IN...BUT
THINK IT WILL BE IN THE AFTN WITH SFC TROUGH PUSHING THROUGH. ALL
SITES SHOULD SEE LOWERING CIGS/VSBYS DURING THE NIGHT...WITH -RA AT
KIWD/KCMX...AS A LOW PRESSURE SYSTEM APPROACHES.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
A SURFACE TROUGH STALLING OVER LAKE SUPERIOR TODAY WILL BRING A
DIMINISHING TREND TO THE WINDS THROUGH MUCH OF THE DAY. A LOW
DEVELOPING ALONG THE SURFACE TROUGH IN THE CENTRAL PLAINS
TODAY...WILL BEGIN TO MOVE NORTHEAST TONIGHT AND OVER CENTRAL UPPER
MICHIGAN ON SATURDAY. EXPECT INCREASING EAST TO NORTHEAST WINDS LATE
THIS AFTERNOON OVER THE WEST AND THE REST OVER THE AREA
TONIGHT...WITH GUSTS UP TO 30KTS OVER THE NORTH HALF OF THE LAKE
TONIGHT. AS THE LOW MOVES EAST ON SATURDAY NIGHT...NORTH GALES OF
35KTS ARE EXPECTED OVER WEST CENTRAL LAKE SUPERIOR. THE GALES SHOULD
SPREAD EAST ON SUNDAY AS WINDS SHIFT TO THE NORTHWEST...BEFORE
DIMINISHING BELOW 20KTS ON SUNDAY NIGHT AS HIGH PRESSURE MOVES OVER
LAKE SUPERIOR. A SURFACE TROUGH MOVING ACROSS LAKE SUPERIOR ON
MONDAY AFTERNOON AND EVENING WILL PROVIDE ANOTHER PERIOD OF STRONG
SOUTHWEST WINDS...WITH THE POTENTIAL OF NORTHWEST GALES TO 35KTS
BEHIND THE TROUGH MONDAY NIGHT AND TUESDAY MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY AFTERNOON FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
DISCUSSION...KC
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
551 AM CST FRI NOV 25 2011
.SHORT TERM...TODAY THROUGH MONDAY
301 AM CST FRI NOV 25 2011
BIG CHANGES COMING OVER THE NEXT FEW DAYS AS RAIN STARTS UP
TONIGHT AHEAD OF A COLD FRONT WHICH WILL KNOCK TEMPERATURES DOWN
ON SATURDAY. BEYOND THIS...THERE IS MUCH UNCERTAINTY FOR SATURDAY
NIGHT INTO SUNDAY WITH WHETHER AN ACCUMULATING SNOW WILL OCCUR.
CURRENTLY...MILD CONDITIONS WERE OBSERVED ACROSS THE REGION DUE
TO GUSTY SOUTH TO SOUTHWEST WINDS AT THE SURFACE AHEAD OF A COLD
FRONT THAT EXTENDS FROM SOUTHWEST ONTARIO THROUGH NORTHERN
MINNESOTA ON INTO CENTRAL SOUTH DAKOTA. FURTHER ALOFT...GENERAL
SOUTHWEST FLOW AHEAD OF TROUGHING DUE TO A NORTHERN AND SOUTHERN
STREAM LOW WAS HELPING TO ADVECT MID TO HIGH LEVEL CLOUDS INTO THE
REGION. AS THE SOUTHERN STREAM TROUGH PROPAGATES EAST INTO THE
SOUTHERN PLAINS THIS MORNING...LOW LEVEL MOISTURE ADVECTION WILL
BE ON THE INCREASE AS A SURFACE LOW DEEPENS ACROSS THE NORTHERN
PLAINS. AS A RESULT...ANOTHER LOW LEVEL STRATUS DECK IS EXPECTED
TO DEVELOP NORTHWARD THIS MORNING FROM THE SOUTHERN PLAINS. THE
LATEST IR SCANS AT 8Z SHOWS THE LEADING EDGE OF THIS STRATUS NEAR
EMPORIA KANSAS...WHICH CORRELATES WELL TO THE 25.07Z RUC
950-900MB LAYER RH. THIS RUN OF THE RUC SHOWS THE HIGHER RH VALUES
INCREASING RAPIDLY THIS MORNING ACROSS THE SOUTHEASTERN HALF OF
IOWA TOWARD THE NORTHERN HALF OF LAKE MICHIGAN BY 18Z TODAY.
25.07Z RUC AND 25.00Z NAM/GFS SOUNDINGS FROM ACROSS THE REGION
SHOW THIS HIGHER RH BEING TRAPPED UNDER A STOUT 900-850MB
INVERSION AND THEREFORE HAVE GONE WITH A MORE PESSIMISTIC CLOUD
FORECAST TODAY. THIS CLOUD COVER WILL LIMIT HOW MUCH WARMING
CAN OCCUR INTO THE AFTERNOON WITH THE HIGHS LIKELY COMING THIS
MORNING.
AFTER THE STRATUS FILLS IN...THE NEXT QUESTION IS WHEN WILL THE
RAIN START UP TONIGHT. 25.00Z NAM AND GFS SOUNDINGS SHOW A DECENT
DRY LAYER CENTERED ON 800MB THAT WILL NEED TO BE OVERCOME FOR ANY
PRECIPITATION TO MAKE IT DOWN TO THE GROUND. BASED ON THESE
SOUNDINGS AND MID LEVEL QG FORCING FIELDS...IT APPEARS THAT THE
DEEP MOISTURE AND FORCING COMES TOGETHER LATER TONIGHT AHEAD OF
THE SURFACE COLD FRONT AND MID LEVEL TROUGH. THE THERMAL PROFILE
WILL BE WARM ENOUGH FOR THIS PRECIPITATION TO BE IN ALL LIQUID
FORM THROUGH SATURDAY MORNING BEFORE THE FRONT COMES THROUGH.
AFTER THE FRONT COMES THROUGH THE REGION SATURDAY MORNING INTO
EARLY SATURDAY AFTERNOON...UNCERTAINTY TAKES OVER WITH WHAT WILL
OCCUR SATURDAY NIGHT INTO SUNDAY. THE ONE THING THAT APPEARS TO
BE CERTAIN IS THAT COLDER AIR WILL ADVECT INTO THE REGION IN THE
LOW LEVELS BRINGING MUCH OF THE THERMAL PROFILE TO BELOW FREEZING
AND SUPPORTIVE OF SNOW BEING THE PRECIPITATION TYPE.
THE MAIN UNCERTAINTY LIES WITH THE DIFFERENCES BETWEEN THE US AND
NON-US MODEL SOLUTIONS WITH THE STRENGTH AND TRACK OF THE TROUGH.
BASED ON INPUT FROM HPC/S MODEL DIAGNOSTICS DESK...THE UNFAVORED
SOLUTION IS THE 25.00Z NAM/GFS AND 24.21Z SREF MEAN WHICH PRODUCE
A DEEPER...CLOSED OFF MID LEVEL LOW WHICH BRINGS THE DEFORMATION
AXIS THROUGH THE HEART OF THE FORECAST AREA. THESE SOLUTIONS WOULD
LIKELY LEAD TO AN ACCUMULATING SNOW ACROSS MUCH OF THE REGION.
THESE MODELS ALSO DEVELOPS A VERY TIGHT PRESSURE GRADIENT IN THE
LOW LEVEL COLD AIR ADVECTION POCKET ON THE SOUTHWEST SIDE OF THE
SURFACE LOW WHICH WOULD BRING GUSTS UP NEAR ADVISORY CRITERIA.
HOWEVER...AT THIS POINT THE FAVORED SOLUTION FOR SATURDAY NIGHT
INTO SUNDAY IS WITH THE 25.00Z ECMWF/UKMET/CANADIAN MODELS. THESE
FORMS OF GUIDANCE ALL SHOW A MUCH LESS AMPLIFIED...OPEN MID LEVEL
WAVE WITH HARDLY ANY SNOW COMING THROUGH SATURDAY NIGHT.
BASED ON THIS INPUT FROM HPC ...HAVE BACKED OFF ON THE PROBABILITY
FOR PRECIPITATION AND THE WIND GUSTS JUST A TAD ON SATURDAY NIGHT.
FOR ADDITIONAL INFORMATION ON THIS FAVORED TREND...PLEASE SEE THE
LATEST PMDHMD FROM HPC.
COLD AIR WILL REMAIN IN PLACE UNTIL MONDAY WHEN A BRIEF SHOT OF
LOW LEVEL WARM AIR ADVECTION COMES THROUGH THE REGION.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
301 AM CST FRI NOV 25 2011
NOT A WHOLE LOT OF CONFIDENCE GOING INTO THE EXTENDED PERIOD DUE
TO THE ISSUES THIS WEEKEND...BUT HAVE TRENDED TOWARD THE 25.00Z
ECMWF/GEM/UKMET FORECAST WHICH CUT OFF A MID LEVEL LOW ALONG THE
GULF COAST EARLY NEXT WEEK AND SLOWLY BRINGS IT TOWARD THE
NORTHEASTERN US INTO MID WEEK. THIS SETUP WILL KEEP THE REGION IN
A COOL NORTHWESTERLY FLOW ALOFT AND LIMIT ANY KIND OF WARMING
TRENDS. NOT MUCH IN THE WAY OF PRECIPITATION CHANCES EXCEPT FOR AN
OPEN MID LEVEL TROUGH THAT DIVES SOUTHEAST TOWARD THE GREAT LAKES
ON THURSDAY WHICH COULD BRING SOME PRECIPITATION WITH IT.
&&
.AVIATION...THROUGH 12Z SATURDAY
551 AM CST FRI NOV 25 2011
IMMEDIATE CONCERN THIS MORNING DEALS WITH LLWS AT KLSE WITH WINDS
AROUND 35-45KT AROUND 2000FT AGL AND WINDS BELOW 5KT AT THE SURFACE
AS OF 12Z. LOW LEVEL JET AND THUS LLWS EXPECTED TO SLACKEN THIS
MORNING BY 14Z. CONCERN THEN SHIFTS TO SOUTHERLY FLOW ADVECTING
MVFR/IFR STRATUS INTO THE AREA LATER THIS MORNING FROM THE CENTRAL
PLAINS. HAVE CIGS GOING BKN AROUND 800 FEET AT KRST BY 16Z AND
AROUND 1200 FEET AT KLSE AT THE SAME TIME.
FOR TONIGHT...WILL BE WATCHING A LOW PRESSURE SYSTEM AND COLD FRONT
PUSHING EASTWARD INTO THE AREA...SPREADING SCATTERED SHOWERS IN THIS
EVENING...AND MORE WIDESPREAD RAIN/AREAS OF FOG IN AFTER MIDNIGHT. IFR
CONDITIONS EXPECTED TO CONTINUE AT KRST WHILE MVFR CONDITIONS AT
KLSE EXPECTED TO DETERIORATE INTO IFR AFTER 08Z.
&&
.CLIMATE...FOR TODAY
301 AM CST FRI NOV 25 2011
RECORD HIGHEST LOWS MAY BE BROKEN TODAY AT BOTH ROCHESTER AND LA
CROSSE WITH TEMPERATURES THIS MORNING FAIRLY MILD IN THE UPPER 40S
TO AROUND 50. THE RECORD HIGHEST LOW TEMPERATURE FOR ROCHESTER
TODAY IS 37 FROM 1915. THE RECORD HIGHEST LOW TEMPERATURE FOR LA
CROSSE TODAY IS 42 IN 1998. FORECAST TEMPERATURES AT MIDNIGHT
TONIGHT ARE EXPECTED TO BE ABOVE THESE VALUES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
301 AM CST FRI NOV 25 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
CLIMATE...HALBACH
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
241 PM PST FRI NOV 25 2011
.DISCUSSION...AS OF 2:35 PM PST FRIDAY...RATHER MUNDANE WEATHER
PATTERN SETTING UP OVER THE REGION THROUGH NEXT WEEK WITH A
WARMING TREND.
DESPITE A SOMEWHAT DAMP START THIS MORNING WITH LIGHT
RAIN...PRECIP ENDED BY MORNING WITH SOME SCATTERED OF CLOUDS.
HOWEVER...SAN FRANCISCO BAY NORTHWARD CONTINUES TO STRUGGLE FOR
SUNSHINE. AS A RESULT...MANY LOCATIONS ARE REMAINING RATHER COOL.
DO EXPECT SOME THINNING OF THE CLOUD COVER OVER THE NEXT FEW HOURS
WITH AN UPTICK IN TEMPERATURE. MOUNTAIN VIEW SOUTHWARD ON THE THE
OTHER HAND IS CURRENTLY EXPERIENCING WALL TO WALL SUNSHINE WITH
TEMPERATURES IN THE 60S.
SHORT TERM(TONIGHT-MONDAY)...
THE FRONTAL BOUNDARY FROM THIS MORNING WILL CONTINUE TO DISSIPATE
THIS EVENING. THE MAIN WEATHER CONCERN FOR TONIGHT WILL BE RESIDUAL
BOUNDARY LAYER MOISTURE AIDING IN FOG DEVELOPMENT. FOR NOW...WILL
KEEP PATCHY DENSE FOG POSS FOR PORTIONS OF THE EAST BAY AND INTO
THE DELTA AS A RESULT OF POSS CENTRAL VALLEY FOG. NORTH BAY WILL
HAVE A CHANCE FOR PATCHY FOG AS WELL...BUT PROBABLY NOT AS DENSE.
IF THE CLOUD COVER CURRENTLY OVER THE NORTH BAY DOES NOT DISSIPATE
FOG DEVELOPMENT MAY BE HAMPERED. LOCATIONS OVER THE SOUTHERN
PORTION OF THE CWA ARE LESS LIKELY TO SEE VALLEY FOG. FLOW OVER
THIS REGION APPEARS TO BE SLIGHTLY OFFSHORE AT 925 MB AND BOUNDARY
LAYER MOISTURE IS LESS.
OTHERWISE...LITTLE CHANGE WAS MADE TO THE SHORT TERM FORECAST. THE
LONG WAVE PATTERN CONTINUES TO SHOW A DECENT RIDGE OF HIGH PRESSURE
BUILDING OVER THE REGION. A GRADUAL WARMING AND DRYING TREND CAN
BE EXPECTED. BY SUNDAY AND MONDAY...MODEL GUIDANCE EVEN INDICATES
850 TEMPS 16.5-18 C. THEREFORE HAVE RAISED TEMPERATURES SLIGHT FOR
MAX TEMPS. HOWEVER...DO NOT EXPECT FULL POTENTIAL OF 18C TO
REALIZED GIVEN THE REDUCE AMOUNT OF INSOLATION THIS TIME OF YEAR.
LONG TERM(TUESDAY-FRIDAY)...
THE MILD WEATHER HOLDS ON FOR TUESDAY AND PART OF WEDNESDAY AS
HIGH PRESSURE REMAIN. MEDIUM RANGE MODELS BREAK DOWN THE RIDGE AS
A LOW BEGINS TO DROP S OVER THE PAC NW. THERE ARE DIFFERENCE
AMONGST THE MODELS...BUT ALL SUGGEST COOLER WEATHER. THE REAL
QUESTION WILL BE IF THERE IS ANY PRECIP WITH THE PASSING UPPER LOW
FROM THE N OR THE CUT OFF LOW OFF THE COAST? CURRENT FORECAST WILL
REMAIN DRY BUT THE ECMWF DOES INDICATE A FEW HUNDREDTHS POSS NEXT THURSDAY.
&&
.AVIATION...AS OF 9:35 AM PST FRIDAY...A LARGE AREA OF STRATUS
WILL CONTINUE TO IMPACT KSJC NORTHWARD THROUGH AT LEAST 19Z. THE
NAM...WRF...AND HRRR INDICATE CLEARING AT THE AIRPORTS ANYWHERE
FROM 19Z TO 21Z...SO THERE IS AN INCREASED CONFIDENCE THAT THERE
WILL BE SUNNY SKIES THIS AFTERNOON. OTHERWISE...NEARLY STAGNANT
FLOW OVER THE REGION WILL BRING LIGHT AND VARIABLE WINDS. A FEW OF
THE SHORT TERM MODELS ARE HINTING AT GROUND FOG FORMING
OVERNIGHT...LOW CONFIDENCE.
VICINITY OF KSFO...MVFR CIGS AROUND 1500 FEET WILL PREVAIL THROUGH
AT LEAST 19Z. MODERATE CONFIDENCE. LIGHT AND VARIABLE WINDS THIS
AFTERNOON. POSSIBLE LOW CLOUDS OR GROUND FOG OVERNIGHT AT BOTH
TERMINALS. LOW CONFIDENCE.
KSFO BRIDGE APPROACH...MVFR CIGS THROUGH 20Z. OTHERWISE...SIMILAR
TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH
AT LEAST 01Z. SHORT TERM MODELS INDICATE PATCHY GROUND FOG WILL
DEVELOP LATE THIS EVENING INTO THE OVERNIGHT HOURS. LOW CONFIDENCE.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
SCA...ROUGH BAR ADVISORY FOR SF BAR
&&
$$
PUBLIC FORECAST: MM
AVIATION/MARINE: RILEY
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
939 AM PST FRI NOV 25 2011
.DISCUSSION...AS OF 8:33 AM PST FRIDAY...THE MAIN WEATHER FEATURE
OF NOTE THIS MORNING IS A WEAK DISSIPATING COLD FRONT CURRENTLY
DRAPED OVER THE BAY AREA. AS NOTED EARLIER THIS MORNING...THERE IS
LITTLE FANFARE ASSOCIATED WITH THE COLD FRONT OTHER THAN VERY
LIGHT RAIN. IN FACT...THE PRECIP IS VERY SHALLOW WITH NO RADAR
RETURNS. HOWEVER...AUTOMATED GAUGES INDICATE A FEW HUNDREDTHS OVER
THE LAST SIX HOURS AND A HUNDREDTH OR TWO OVER THE LAST HOUR. ALL
RAINFALL HAS BE OBSERVED NORTH OF GILROY. THE COLD FRONT ALSO
HELPED TO INCREASE THE BOUNDARY LAYER RH WHICH HAS RESULTED IN
SOME PATCHY FOG AROUND SF BAY AND THE N BAY VALLEYS. WILL DO A
MORNING UPDATE TO FRESHEN UP THE WORDING WITH VALLEY FOG AND TO
REMOVE IT IN THE SALINAS VALLEY.
OTHERWISE...THE COLD FRONT WILL CONTINUE TO WASH OUT OVER THE CWA
WITH A GRADUAL CLEARING THROUGH THE AFTERNOON. TEMPERATURES WILL
REMAIN SEASONABLE COOL AND IN THE LOWER 60S. THERE AFTER...A
RATHER BENIGN WEATHER PATTERN WILL BE ESTABLISHED ACROSS MUCH OF
CALIFORNIA AS STRONG HIGH PRESSURE BUILDS IN THROUGH NEXT WEEK. A
GRADUAL WARMING TREND CAN BE EXPECT THROUGH WEEKEND WITH NIGHT AND
MORNING VALLEY FOG.
&&
.AVIATION...AS OF 9:35 AM PST FRIDAY...A LARGE AREA OF STRATUS
WILL CONTINUE TO IMPACT KSJC NORTHWARD THROUGH AT LEAST 19Z. THE
NAM...WRF...AND HRRR INDICATE CLEARING AT THE AIRPORTS ANYWHERE
FROM 19Z TO 21Z...SO THERE IS AN INCREASED CONFIDENCE THAT THERE
WILL BE SUNNY SKIES THIS AFTERNOON. OTHERWISE...NEARLY STAGNANT
FLOW OVER THE REGION WILL BRING LIGHT AND VARIABLE WINDS. A FEW OF
THE SHORT TERM MODELS ARE HINTING AT GROUND FOG FORMING
OVERNIGHT...LOW CONFIDENCE.
VICINITY OF KSFO...MVFR CIGS AROUND 1500 FEET WILL PREVAIL THROUGH
AT LEAST 19Z. MODERATE CONFIDENCE. LIGHT AND VARIABLE WINDS THIS
AFTERNOON. POSSIBLE LOW CLOUDS OR GROUND FOG OVERNIGHT AT BOTH
TERMINALS. LOW CONFIDENCE.
KSFO BRIDGE APPROACH...MVFR CIGS THROUGH 20Z. OTHERWISE...SIMILAR
TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH
AT LEAST 01Z. SHORT TERM MODELS INDICATE PATCHY GROUND FOG WILL
DEVELOP LATE THIS EVENING INTO THE OVERNIGHT HOURS. LOW CONFIDENCE.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
SCA...ROUGH BAR ADVISORY FOR SF BAR UNTIL 3 PM
&&
$$
PUBLIC FORECAST: MM
AVIATION/MARINE: RILEY
AREA FORECAST DISCUSSION...UPDATED
NWS DES MOINES IA
1145 AM CST FRI NOV 25 2011
...UPDATED FOR 18Z AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
STRATUS FIELD IS LIFTING THROUGH EASTERN KS AS LOW LEVEL MOISTURE
CONTINUES TO ADVECT NORTHWARD TOWARD IOWA. THE MOISTURE IS CENTERED
NEAR 950 MB. THE LATEST RUC 950 MB CONDENSATION PRESSURE DEFICITS
ARE HANDLING THE STRATUS PLACEMENT WELL AND SUGGESTS IT WILL SPREAD
NORTHEAST OVER MUCH OF CNTRL IA THIS MORNING. CIRRUS WILL ALSO BE
THICKENING OVER THE STATE TODAY AND IN COMBINATION WITH THE
STRATUS...WILL RESULT IN MOSTLY CLOUDY CONDITIONS. THIS WILL HAVE AN
IMPACT ON HIGH TEMPERATURES. READINGS AT 3 AM REMAIN QUITE MILD IN
THE MID TO UPPER 40S. ANY SUNSHINE THIS MORNING COULD QUICKLY PUSH
READINGS WELL INTO THE 50S. EXPECT CLOUDS TO BECOME PREVALENT BY MID
MORNING AND WILL LIMIT TEMPERATURES...THEREFORE HAVE TEMPERED HIGHS
FOR TODAY BACK A FEW DEGREES AND MORE INTO THE MID TO UPPER 50S.
THIS WILL BE TOO WARM IF THE STRATUS LINGERS ALL DAY.
THE INITIAL SHORT WAVE WILL REACH WESTERN IA BY THIS AFTERNOON WITH
INCREASING QG FORCING AND THE MID LEVEL DRY AIR SLOWLY ERODING AS
EVAPORATING PRECIPITATION FALLS INTO THIS LAYER. POSSIBLE BY VERY
LATE AFTERNOON THAT A FEW SPRINKLES OR LIGHT RAIN COULD REACH THE
SFC OVER THE FAR WEST CENTRAL AND SOUTHWEST. THEREFORE HAVE ADDED
LOW POPS.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
FORECAST PROBLEM IN THE LONG TERM CONTINUES TO BE THE UPPER TROUGH
MOVING THROUGH THE UPPER MIDWEST THIS WEEKEND. A NORTHERN STREAM
SHORTWAVE WAS MOVING EAST THROUGH THE NORTHERN ROCKIES THIS MORNING
WHILE A WEAKER SOUTHERN STREAM WAVE WAS MOVING THROUGH THE DESERT
SOUTHWEST. THE NORTHERN SYSTEM IS FORECAST TO MOVE SOUTHEAST INTO
THE CENTRAL UNITED STATES AND DEEPEN BY SATURDAY. THE 00Z GFS/NAM
PHASE THE TWO WAVES IN THE CENTRAL STATE AND SIGNIFICANTLY DEEPEN
THE TROUGH INTO A CLOSED 500 MB LOW. THE 00Z ECMWF REMAINS
CONSISTENT WITH IT/S PREVIOUS RUN KEEPING THE SHORT WAVE ENERGY
SEPARATE. AS A RESULT...THE NORTHERN SHORTWAVE REMAINS A POSITIVE
TILTED OPEN WAVE. THE GFS/NAM SOLUTIONS HAVE A MUCH DEEPER SURFACE
LOW WHICH DEVELOPS NORTHEAST OF CENTRAL IOWA. WITH THE DEEPER
SYSTEM...THE WIND FIELDS ARE STRONG. IF THE GFS/NAM SOLUTIONS
VERIFY...AT A MINIMUM CENTRAL IOWA SHOULD HAVE A DECENT WIND EVENT
AND SOME LIGHT SNOW DUE TO THE STRONGER FORCING. IF THE WEAKER
LOOKING ECMWF VERIFIES...IT WOULD BE WINDY...BUT PROBABLY BELOW
ADVISORY CRITERIA AND LESS SNOW CHANCES. BASED THE FORECAST ON A
COMPROMISE BETWEEN THESE VARIED SOLUTIONS. NO HEADLINES FOR WIND AT
THIS POINT...BUT WILL MENTION WINDY CONDITIONS IN THE HWO. WILL
ALSO MENTION THE POSSIBILITY OF LIGHT SNOW...ESPECIALLY NORTH...BUT
ACCUMULATIONS SHOULD BE LIGHT.
MOISTURE STEAMING NORTHEAST AHEAD OF THE FRONT TONIGHT ALONG WITH A
LARGE AREA OF UPWARD FORCING AHEAD OF THE UPPER TROUGH SUPPORTS HIGH
POPS FOR RAIN TONIGHT.
ANOTHER COLD FRONT SHOULD MOVE THROUGH THE STATE LATE MONDAY. LACK
OF SIGNIFICANT FORCING AND MOISTURE SHOULD KEEP IT DRY. THE 00Z
ECMWF IS ADVERTISING A STRONGER COLD FRONT LATE NEXT WEEK.
CONFIDENCE ON THE TIMING OF THE FRONTS IS LOW DUE TO MODEL
DIFFERENCES NEXT WEEK BETWEEN THE ECMWF AND THE OPERATIONAL GFS.
&&
.AVIATION...25/18Z
STRATUS SHIELD HAS ADVANCED TO EVERYWHERE ACROSS THE TAF FORECAST
AREA AND WILL REMAIN IN PLACE THROUGH THE FORECAST PERIOD. CIGS MAY
VACILLATE BETWEEN 008 AND 015 THROUGH 00Z BUT NO PCPN EXPECTED.
AFT 00Z UPPER LEVEL LOW PRESSURE ACROSS THE HIGH PLAINS WILL ADVANCE
EAST WHILE A COLD FRONT AT THE SURFACE ENTERS FROM THE WEST. RAIN
WILL BEGIN BETWEEN 03Z AND 06Z THEN ADVANCE EAST OVERNIGHT. THE COLD
FRONT WILL BE EAST OF THE TAF LOCATIONS BY 15Z SAT AND WE WILL
LIKELY SEE FALLING TEMPS AFTER THAT TIME BUT TEMPS SHOULD REMAIN
WARM ENOUGH THROUGH 18Z FOR REMAINING PRECIP TO STAY AS RAIN.
BEYOND THE FCST PD...PRECIP WILL CHANGE OVER TO A MIX AND THEN LIGHT
SNOW AFT 18Z. A NORTHWEST WIND WILL ALSO BE ON THE INCREASE AFT 12Z
AS THE COLD AIR MOVING IN DEEPENS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DONAVON
LONG TERM...JOHNSON
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1251 PM EST FRI NOV 25 2011
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT UPR
RDGING IN PLACE OVER NAMERICA DOWNSTREAM OF TROFFING OVER THE PAC NW
AND WRN CAN. CLOSER TO THE SFC...THE UPR GRT LKS ARE DOMINATED BY A
STRONG SW FLOW BTWN HI PRES IN THE MID ATLANTIC STATES AND LO PRES
OVER NRN ONTARIO. GRAND MARAIS IN ALGER COUNTY REPORTED SW WIND
GUSTS UP TO 37 MPH AT 0330Z. THE 00Z INL AND MPX RAOBS ARE QUITE DRY
/IN FACT...THE 00Z H7 DEWPT DEPRESSION AT ABERDEEN SDAKOTA WAS
42C/...SO NOTHING BUT HI CLDS ARE PRESENT ALONG AND AHEAD OF
ATTENDANT COLD FNT EXTENDING FM THE ONTARIO LO THRU NW MN INTO
NDAKOTA. MORE EXTENSIVE LO CLDS FOLLOW THE FROPA OVER NW NDAKOTA AND
SCNTRL CAN WITH SHALLOW COLD AIR INFUSION. OVER THE E HALF OF THE
CWA...LLVL MSTR DEPICTED ON THE 00Z GRB RAOB BLO SHARP INVRN BASE
NEAR H95 HAS RESULTED IN EXTENSIVE LO CLD. OTRW TEMPS ARE WELL ABV
NORMAL FOR THE SEASON...WITH 00Z H85 TEMPS RANGING FM 13C AT GRB AND
INL TO 15C AT MPX. SFC TEPS ARE STILL WELL INTO THE 40S AT MANY
PLACES EARLY THIS MRNG...10 TO 15 DEGREES ABV THE NORMAL HI TEMPS
FOR THE DATE. WELL TO THE W... WV IMAGERY INDICATES A STRONGER
SHRTWV IS APRCHG THE PAC NW...WHERE 12Z-24Z H3 FALLS UP TO 100M
OCCURRED.
&&
.DISCUSSION...
MAIN FCST CONCERNS SHIFT FM LO CLDS/WELL ABV NORMAL TEMPS TDAY TO
PCPN CHCS TNGT THRU THE WEEKEND.
TDAY...SFC HI PRES OVER THE MID ATLANTIC IS PROGGED TO DRIFT OFF THE
SE COAST WHILE LO PRES NOW OVER NRN ONTARIO WL DRIFT ACRS QUEBEC...
DRAGGING ATTENDANT COLD FNT INTO THE CWA DURING THE AFTN. ALTHOUGH
SFC TEMPS WL BE HELD DOWN ESPECIALLY OVER THE NW WITH THE ARRIVAL OF
LLVL COLDER AIR/ARRIVAL OF MORE LO CLDS BEHIND THE FROPA...READINGS
WL STILL BE WELL ABV NORMAL...ESPECIALLY OVER THE SCNTRL WHERE THE
LO CLDS ARE MORE LIKELY TO BREAK UP. THE SW FLOW OFF LK MI THRU THE
DAY AND LO SUN ANGLE WL LIKELY RESULT IN A PERSISTENCE OF THE LO CLD
OVER THE E EVEN THOUGH THE STRONGER SW WINDS OBSVD EARLY THIS MRNG
WL DIMINISH QUICKLY AS THE PRES GRADIENT SLACKENS. ALTHOUGH SOME
MODELS GENERATE LGT PCPN OVER THE CWA WITH THE COLD FROPA...PREFER
THE DRY NAM GIVEN THE EXCESSIVE MID LVL DRYNESS OBSVD UPSTREAM.
TNGT...STRONGER SHRTWV NOW MOVING INTO THE PAC NW IS FCST TO DEEPEN
UPR TROF IN THE PLAINS...WITH SFC LO PRES DVLPG OVER NW WI ON
STALLED FNT THAT WL REMAIN ACRS THE CWA. ALTHOUGH LINGERING MID LVL
DRY AIR WL LIMIT PCPN CHCS IN THE EVNG...EXPANDING DEEP LYR QVECTOR
CNVGC/UPR DVGC/SHARPENING H85-7 FGEN ASSOCIATED WITH APRCHG SHRTWV/
EXIT REGION OF ACCOMPANYING 120KT H3 JET MAX WL INCRS RA CHCS
ESPECIALLY OVER THE SW HALF LATER. TENDED TOWARD THE SOMEWHAT WETTER
00Z GFS/12Z ECMWF GIVEN APPARENT STRENGTH OF SHRTWV NOW APRCHG THE
PAC NW.
SAT...MODEL DISCREPANCIES BECOME MORE PRONOUNCED WITH THE HANDLING
OF THE DVLPG LO...SO CONFIDENCE IN THE FCST WL DIMINISH. GIVEN
APPARENT STRENGHT OF INCOMING SHRTWV AS MENTIONED ABOVE...TENDED
TOWARD THE DEEPER 00Z NAM/GFS SCENARIOS THAT SHOW CUTOFF H5 LO
FORMING SOMEWHERE OVER THE UPR MS RIVER VALLEY/UPR MIDWEST.
HOWEVER...NCEP PREFERENCE FOR THE WEAKER SOLNS SHOWN BY THE 12Z
ECMWF AND 00Z CNDN LOWER CONFIDENCE FURTHER. FORTUNATELY...THERE IS
RELATIVELY LTL DIFFERENCE IN THE SFC LO PLACEMENT AMONG THE VARIOUS
MODELS DESPITE THE DIFFERENCES IN INTENSITY. MODELS SHOW SFC LO
MOVING TO NEAR MQT BY 00Z SUN. ALTHOUGH DRY SLOTTING TO THE E OF THE
H5 LO WL LIKELY RESULT IN A DIMINISHING TREND OF THE PCPN OVER
MAINLY THE CNTRL AND E...EXPECT HEAVIER PCPN TO LINGER OVER THE W FM
IWD-CMX THRU THE DAY CLOSER TO THE TRACK OF THE ACCOMPANYING H85 LO.
PER GFS FCST WBLB ZERO HGT FCST TO FALL NEAR 1K FT AGL BY 00Z
SUN...EXPECT ENUF COLD AIR TO ARRIVE LATE IN THE DAY TO RESULT IN AT
LEAST A MIX OF RA/SN NEAR IWD UNDER THE SHARPER CYC NLY FLOW.
SAT NGT THRU SUN...VARIOUS MODELS SHOW SFC LO DRIFTING SLOWLY TO THE
NE TO SSE OF JAMES BAY BY LATE IN THE DAY SUN. THE NAM BECOMES A
PARTICULAR OUTLIER SHOWING THE LO LINGERING NEAR UPR MI...SO
REJECTED THIS FCST. THE OTHER PREFERRED MODELS SUG PCPN WITHIN COMMA
HEAD MSTR UNDER SHARPER NNW CYC FLOW/H85 THERMAL TROFFING WL IMPACT
MAINLY THE NW HALF AND SLOWLY CHG TO SN AS COLDER AIR MOVES OVHD...
WITH BOTH THE 00Z GFS/12Z ECMWF INDICATING H85 TEMPS FALLING TO ARND
-9C...LO ENUF FOR LK EFFECT PCPN CONSIDERING LK SUP TEMPS ARND 5C.
HOWEVER...EVEN THE DEEPER GFS SUGS SN GROWTH MICROPHYSICS WL NOT BE
VERY FVRBL GIVEN FCST WEAK UVV IN THE DENDRITIC SN GROWTH ZN. EVEN
SO...SOME LO END ADVY SN AMNTS MAY BE PSBL OVER THE W WITH LK
ENHANCEMENT AS THE SN SHOULD BE WET AND HEAVY. THE NEW 00Z ECMWF
INDICATES GOOD CONTINUITY WITH THE 12Z RUN...BUT SHOWS QUICKER
DRYING ON SUN WITH A WEAKER CYC FLOW/FASTER EXIT THAN INDICATED BY
THE DEEPER GFS. TENDED TOWARD HIER POPS OVER THE W TO THE HURON MTNS
WHERE THE UPSLOPE NNW FLOW WOULD HAVE A MORE SGNFT IMPACT AS HINTED
BY THE 00Z CNDN MODEL. EXPECT A DRYING TREND W-E ON SUN NGT WITH THE
ARRIVAL OF A HI PRES RDG.
EXTENDED RANGE...EXPECT A MORE SEASONABLY CHILLY PATTERN WITH NW
FLOW ALF ALLOWING FOR FREQUENT SHRTWV PASSAGES/POTENTIAL LES
EPISODES. MADE FEW CHGS TO ALL BLEND FCST NUMBERS.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
ANOTHER DIFFICULT TAF FCST. LOW CLOUDS/VSBY HAVE EXITED KSAW BUT
SHOULD RETURN BY LATE AFTN AS LOW CLOUDS OVR WI STREAM NORTHWARD.
MAY SEE YET ANOTHER NIGHT OF CONDITIONS NEAR AIRFIELD MINS BUT SINCE
ESE WINDS ARE NOT AS FAVORABLE FOR LOWER CONDITIONS...KEPT CIGS/VSBY
LIFR. AT KCMX...LOW CLOUDS HAVE JUST RECENTLY DEVELOPED AS MOISTURE
FM ONTARIO DROPS IN ON DEVELOPING N/NE WINDS. CLOUDS MAY BE MORE
VARIABLE THIS AFTN...BUT OVERALL THE PREVAILING TREND WILL BE FOR
THE LOW CLOUDS TO STICK AROUND THROUGH TONIGHT. ONCE WINDS BECOME
MORE EASTERLY...HAVE LOWERED CIGS/VSBY TO IFR OVERNIGHT TONIGHT...BUT
THIS MAY NOT BE LOW ENOUGH GIVEN FAVORABLE EAST WIND DIRECTION. AS
FOR KIWD...JUST MID-HIGH CLOUDS THUS FAR...BUT EXPECT LOWER CIGS TO
DEVELOP LATE TODAY AS THE LOW-CLOUDS IN WESTERN AND CNTRL WI PUSH
NORTHWARD. EXPECT RAIN TO DEVELOP LATE TONIGHT AT ALL THREE SITES AS
LOW PRESSURE SYSTEM LIFTS TOWARD AREA. MAINLY LIFR CONDITIONS
EXPECTED FOR ALL SITES SATURDAY MORNING...WITH ONLY SLOW IMPROVEMENT
SATURDAY AFTN. &&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
A SURFACE TROUGH STALLING OVER LAKE SUPERIOR TODAY WILL BRING A
DIMINISHING TREND TO THE WINDS THROUGH MUCH OF THE DAY. A LOW
DEVELOPING ALONG THE SURFACE TROUGH IN THE CENTRAL PLAINS
TODAY...WILL BEGIN TO MOVE NORTHEAST TONIGHT AND OVER CENTRAL UPPER
MICHIGAN ON SATURDAY. EXPECT INCREASING EAST TO NORTHEAST WINDS LATE
THIS AFTERNOON OVER THE WEST AND THE REST OVER THE AREA
TONIGHT...WITH GUSTS UP TO 30KTS OVER THE NORTH HALF OF THE LAKE
TONIGHT. AS THE LOW MOVES EAST ON SATURDAY NIGHT...NORTH GALES OF
35KTS ARE EXPECTED OVER WEST CENTRAL LAKE SUPERIOR. THE GALES SHOULD
SPREAD EAST ON SUNDAY AS WINDS SHIFT TO THE NORTHWEST...BEFORE
DIMINISHING BELOW 20KTS ON SUNDAY NIGHT AS HIGH PRESSURE MOVES OVER
LAKE SUPERIOR. A SURFACE TROUGH MOVING ACROSS LAKE SUPERIOR ON
MONDAY AFTERNOON AND EVENING WILL PROVIDE ANOTHER PERIOD OF STRONG
SOUTHWEST WINDS...WITH THE POTENTIAL OF NORTHWEST GALES TO 35KTS
BEHIND THE TROUGH MONDAY NIGHT AND TUESDAY MORNING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY AFTERNOON FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
DISCUSSION...KC
AVIATION...JLA
MARINE...SRF
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
254 PM MST FRI NOV 25 2011
.DISCUSSION...
VERY DRY COLD AIR ADVECTION IS TAKING HOLD OF THE REGION LATE THIS
AFTERNOON BEHIND OUR THANKSGIVING STORM SYSTEM. A THIN BAND OF
RAIN AND STORMS IS LINGERING ALONG THE PACIFIC FRONTAL BNDRY OVER
THE EAST CENTRAL PLAINS. ANOTHER AREA OF RAIN/SNOW IS SLIDING
EAST ACROSS THE NE PLAINS ALONG AND BEHIND THE HIGH PLAINS COLD
FRONT. REMOVED POPS FROM ALL AREAS EXCEPT THE NE PLAINS WHERE THE
GFS...EURO AND RUC HOLD ON TO SOME QPF THROUGH 11PM. OTHERWISE...
WINDS WILL BE ON THE BREEZY SIDE THROUGH THE EVENING ACROSS THE
STATE AS LAMINAR NW FLOW REMAINS FIRMLY IN PLACE.
THE MEDIUM RANGE FORECAST THROUGH MONDAY WILL BE TRANQUIL AND
COOL WITH LIGHT WINDS AND MOSTLY CLEAR SKIES. THE 12Z GFS/NAM
SOLUTIONS PUSH THE UPPER TROUGH AXIS WELL EAST INTO THE OHIO
RIVER VALLEY AND DEEPEN IT TO A CLOSED LOW THROUGH MONDAY...WHILE
THEIR ENSEMBLE COUNTERPARTS ARE MUCH SLOWER AND DEVELOP THE CLOSED
LOW OVER THE LOWER MS RIVER VALLEY. THE ECMWF AND CANADIAN SOLUTIONS
ARE CLOSER TO THE GFS AND SREF ENSEMBLES SO THIS FORECAST IS MUCH
CLOSER TO THE ECMWF...WHICH IS COOLER FOR THE EASTERN HALF OF NM
THROUGH EARLY NEXT WEEK.
A 587DM H5 UPPER HIGH WILL STILL DEVELOP OVER SOUTHERN CALIFORNIA IN
THE MEANTIME...HOWEVER ITS MAIN ROLE WILL BE TO DEVELOP SURFACE HIGH
PRESSURE OVER THE CENTRAL ROCKIES AND ALLOW FOR A DECENT COLD FRONT
TO MOVE SOUTH DOWN THE PLAINS TUESDAY. SKIES WILL REMAIN MOSTLY
SUNNY WITH THIN HIGH CLOUDS TRAVERSING SE OVER THE EASTERN PERIPHERY
OF THE RIDGE.
DESPITE MODEL DIFFERENCES IN THE MEDIUM RANGE...THE EXTENDED GFS...
ECMWF AND CANADIAN GUIDANCE COME INTO EXCEPTIONALLY GOOD AGREEMENT
FOR LATE NEXT WEEK. THE 587DM H5 RIDGE SLIDES WEST OFF THE CALIFORNIA
COAST THEN SHARPENS TO THE NORTHWEST INTO THE GULF OF ALASKA THROUGH
THURSDAY. THIS ALLOWS A POWERFUL 1050MB SURFACE HIGH TO SLIDE DOWN
THE FRONT RANGE WHILE AN UPPER WAVE BEGINS TO DIG INTO THE GREAT
BASIN. THE COLDEST AIR OF THE SEASON IS POSSIBLE WITH THIS SYSTEM
BY THE END OF THE WEEK. THE UPPER WAVE THEN DEEPENS AND SLIDES EAST
ACROSS NM WITH ABUNDANT MOIST ADVECTION AND THE POTENTIAL FOR OUR
FIRST BIG WINTER STORM.
GUYER
&&
.AVIATION...
UPPER TROUGH AXIS STRETCHED NORTH TO SOUTH ALONG THE EAST SLOPES OF
THE CENTRAL MOUNTAIN CHAIN AT 20Z WILL CONTINUE TO TRACK EASTWARD
AND EXIT NEW MEXICO BY 26/06Z. ISOLD TSRA WILL BE FOUND ALONG
THE AXIS...WITH -SHRA AND MOUNTAIN -SHRASN ELSEWHERE. CONVECTION
WILL OCCASIONALLY OBSCURE HIGHER TERRAIN WITH MAINLY MVFR VSBYS/CIGS.
SURFACE WIND SHIFT TO NW/N OVER ERN HALF OF STATE BEFORE 26/00Z WITH
OCCASIONAL GUSTS TO AROUND 35KT.
DRYING EXPECTED IN THE WAKE OF THE TROUGH FROM THE FAR NW AND WEST
CENTRAL SPREADING EASTWARD THROUGH 26/12Z BUT SOME LINGERING LOW
LEVEL MOISTURE MAY RESULT IN ISOLD IFR CIGS/VSBYS MAINLY IN VALLEYS
OF THE NORTHERN MOUNTAINS. AT LEAST ONE SHORT WAVE IN THE NORTHWEST
FLOW ALOFT WILL PLUNGE INTO EASTERN NEW MEXICO LATE TONIGHT/SATURDAY
TO KEEP A STRONG GRADIENT BOTH ALOFT AND AT THE SURFACE...LEADING TO
GUSTY WINDS PERSISTING IN THAT REGION.
NEXT AVIATION DISCUSSION SCHEDULED FOR 10Z.
&&
.FIRE WEATHER...
WETTING PRECIPITATION WILL CONTINUE TO TAPER OFF FOR THE REST OF THE
AFTERNOON AS THE UPPER TROUGH AXIS TRACKS EAST AND OUT OF NEW
MEXICO. HOWEVER...A FEW THUNDERSTORMS WILL BE FOUND OVER THE EASTERN
PLAINS IMMEDIATELY ALONG THE TROUGH AXIS THIS AFTERNOON. IN
ADDITION...GUSTY NORTHWEST TO NORTH WINDS WILL RAKE A GOOD PART OF
NORTHERN AND CENTRAL NEW MEXICO. THESE WINDS WILL HELP DRY THE
BOUNDARY LAYER TONIGHT FROM NORTHWEST TO SOUTHEAST...BUT SOME
LINGERING LOW LEVEL MOISTURE MAY RESULT IN PATCHY LOW CLOUDS IN
SOME NORTHERN AND/OR SOUTHWEST MOUNTAIN VALLEYS.
THEREFORE...HUMIDITY RECOVERIES SHOULD BE AT LEAST GOOD.
GUSTY NORTHWEST TO NORTH WINDS WILL PERSIST SATURDAY MAINLY OVER THE
EASTERN PLAINS AS THE UPPER RIDGE BUILDS FROM THE WEST AND AT LEAST
ONE MORE SHORT WAVE DIVES SOUTH OUT OF COLORADO. IT SHOULD BE DRY
AREA WIDE WITH TEMPERATURES SLOW TO WARM...ESPECIALLY IN THE
NORTHEAST. VENTILATION WILL BE FAIR TO POOR OVER ALL BUT THE
NORTHEAST PLAINS AND ALONG THE TEXAS BORDER.
NOT MUCH CHANGE IN THE UPPER AIR PATTERN IS ANTICIPATED ON SUNDAY AS
THE RIDGE BUILDS SHARPLY OVER ARIZONA AND WESTERN NEW MEXICO. THE
GRADIENT RELAXES...RESULTING IN LESS WIND OVERALL AND POOR
VENTILATION AREA WIDE. DAYTIME TEMPERATURES SHOULD REBOUND TO WITHIN
A FEW DEGREES OF NORMAL.
THE UPPER RIDGE FLATTENS SLIGHTLY ON MONDAY...ALLOWING A SURFACE
FRONT TO APPROACH THE NORTHEAST CORNER OF NEW MEXICO IN THE
AFTERNOON. CONSEQUENTLY...VENTILATION IMPROVES SOMEWHAT IN THE EAST
BUT REMAINS POOR IN THE WEST. THE FRONT MOVES THROUGH THE PLAINS
MONDAY NIGHT BUT SHOULD BE DRY.
IT SHOULD BE A LITTLE COOLER IN THE EAST TUESDAY...BUT VENTILATION
WILL REMAIN POOR TO FAIR AREA WIDE. EXTENDED FORECAST MODELS ARE
INDICATING AN IMPRESSIVE WINTER STORM SYSTEM COULD DEVELOP IN SPLIT
FLOW OVER THE WESTERN U.S. SOMETIME MID TO LATE NEXT WEEK. THIS
COULD IMPACT NEW MEXICO NEXT THURSDAY THROUGH SATURDAY...BUT THAT
COULD CHANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 26 49 22 53 / 0 0 0 0
DULCE........................... 19 46 15 52 / 0 0 0 0
CUBA............................ 21 48 19 54 / 0 0 0 0
GALLUP.......................... 20 48 14 55 / 0 0 0 0
EL MORRO........................ 19 45 14 52 / 0 0 0 0
GRANTS.......................... 18 48 13 55 / 0 0 0 0
QUEMADO......................... 19 49 16 56 / 0 0 0 0
GLENWOOD........................ 30 61 28 61 / 0 0 0 0
CHAMA........................... 20 42 19 48 / 0 0 0 0
LOS ALAMOS...................... 31 43 29 50 / 0 0 0 0
PECOS........................... 27 42 26 49 / 0 0 0 0
CERRO/QUESTA.................... 21 39 16 48 / 0 0 0 0
RED RIVER....................... 17 33 4 44 / 5 0 0 0
ANGEL FIRE...................... 19 37 5 46 / 5 0 0 0
TAOS............................ 19 43 14 52 / 0 0 0 0
MORA............................ 25 41 23 50 / 0 0 0 0
ESPANOLA........................ 23 49 20 55 / 0 0 0 0
SANTA FE........................ 26 44 24 52 / 0 0 0 0
SANTA FE AIRPORT................ 25 47 21 53 / 0 0 0 0
ALBUQUERQUE FOOTHILLS........... 29 48 30 53 / 0 0 0 0
ALBUQUERQUE HEIGHTS............. 33 50 29 53 / 0 0 0 0
ALBUQUERQUE VALLEY.............. 31 52 24 54 / 0 0 0 0
ALBUQUERQUE WEST MESA........... 28 52 24 54 / 0 0 0 0
LOS LUNAS....................... 27 52 20 55 / 0 0 0 0
RIO RANCHO...................... 26 51 25 54 / 0 0 0 0
SOCORRO......................... 31 54 28 58 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 27 47 26 51 / 0 0 0 0
TIJERAS......................... 27 48 24 52 / 0 0 0 0
MORIARTY/ESTANCIA............... 23 43 18 49 / 0 0 0 0
CLINES CORNERS.................. 26 43 25 48 / 5 0 0 0
GRAN QUIVIRA.................... 28 48 26 52 / 0 0 0 0
CARRIZOZO....................... 30 51 26 53 / 0 0 0 0
RUIDOSO......................... 26 46 24 48 / 5 0 0 0
CAPULIN......................... 24 38 20 51 / 20 0 0 0
RATON........................... 25 45 19 61 / 5 0 0 0
SPRINGER........................ 24 43 20 59 / 5 0 0 0
LAS VEGAS....................... 26 42 23 54 / 5 0 0 0
CLAYTON......................... 28 42 28 58 / 30 0 0 0
ROY............................. 27 42 24 55 / 10 0 0 0
CONCHAS......................... 32 48 25 60 / 5 0 0 0
SANTA ROSA...................... 31 47 27 60 / 0 0 0 0
TUCUMCARI....................... 32 46 26 58 / 10 0 0 0
CLOVIS.......................... 32 46 27 54 / 0 0 0 0
PORTALES........................ 32 47 25 56 / 5 0 0 0
FORT SUMNER..................... 34 49 26 59 / 0 0 0 0
ROSWELL......................... 36 51 25 59 / 0 0 0 0
PICACHO......................... 33 48 25 57 / 0 0 0 0
ELK............................. 30 47 24 52 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
GUYER
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1147 AM CST FRI NOV 25 2011
.SHORT TERM...TODAY THROUGH MONDAY
301 AM CST FRI NOV 25 2011
BIG CHANGES COMING OVER THE NEXT FEW DAYS AS RAIN STARTS UP
TONIGHT AHEAD OF A COLD FRONT WHICH WILL KNOCK TEMPERATURES DOWN
ON SATURDAY. BEYOND THIS...THERE IS MUCH UNCERTAINTY FOR SATURDAY
NIGHT INTO SUNDAY WITH WHETHER AN ACCUMULATING SNOW WILL OCCUR.
CURRENTLY...MILD CONDITIONS WERE OBSERVED ACROSS THE REGION DUE
TO GUSTY SOUTH TO SOUTHWEST WINDS AT THE SURFACE AHEAD OF A COLD
FRONT THAT EXTENDS FROM SOUTHWEST ONTARIO THROUGH NORTHERN
MINNESOTA ON INTO CENTRAL SOUTH DAKOTA. FURTHER ALOFT...GENERAL
SOUTHWEST FLOW AHEAD OF TROUGHING DUE TO A NORTHERN AND SOUTHERN
STREAM LOW WAS HELPING TO ADVECT MID TO HIGH LEVEL CLOUDS INTO THE
REGION. AS THE SOUTHERN STREAM TROUGH PROPAGATES EAST INTO THE
SOUTHERN PLAINS THIS MORNING...LOW LEVEL MOISTURE ADVECTION WILL
BE ON THE INCREASE AS A SURFACE LOW DEEPENS ACROSS THE NORTHERN
PLAINS. AS A RESULT...ANOTHER LOW LEVEL STRATUS DECK IS EXPECTED
TO DEVELOP NORTHWARD THIS MORNING FROM THE SOUTHERN PLAINS. THE
LATEST IR SCANS AT 8Z SHOWS THE LEADING EDGE OF THIS STRATUS NEAR
EMPORIA KANSAS...WHICH CORRELATES WELL TO THE 25.07Z RUC
950-900MB LAYER RH. THIS RUN OF THE RUC SHOWS THE HIGHER RH VALUES
INCREASING RAPIDLY THIS MORNING ACROSS THE SOUTHEASTERN HALF OF
IOWA TOWARD THE NORTHERN HALF OF LAKE MICHIGAN BY 18Z TODAY.
25.07Z RUC AND 25.00Z NAM/GFS SOUNDINGS FROM ACROSS THE REGION
SHOW THIS HIGHER RH BEING TRAPPED UNDER A STOUT 900-850MB
INVERSION AND THEREFORE HAVE GONE WITH A MORE PESSIMISTIC CLOUD
FORECAST TODAY. THIS CLOUD COVER WILL LIMIT HOW MUCH WARMING
CAN OCCUR INTO THE AFTERNOON WITH THE HIGHS LIKELY COMING THIS
MORNING.
AFTER THE STRATUS FILLS IN...THE NEXT QUESTION IS WHEN WILL THE
RAIN START UP TONIGHT. 25.00Z NAM AND GFS SOUNDINGS SHOW A DECENT
DRY LAYER CENTERED ON 800MB THAT WILL NEED TO BE OVERCOME FOR ANY
PRECIPITATION TO MAKE IT DOWN TO THE GROUND. BASED ON THESE
SOUNDINGS AND MID LEVEL QG FORCING FIELDS...IT APPEARS THAT THE
DEEP MOISTURE AND FORCING COMES TOGETHER LATER TONIGHT AHEAD OF
THE SURFACE COLD FRONT AND MID LEVEL TROUGH. THE THERMAL PROFILE
WILL BE WARM ENOUGH FOR THIS PRECIPITATION TO BE IN ALL LIQUID
FORM THROUGH SATURDAY MORNING BEFORE THE FRONT COMES THROUGH.
AFTER THE FRONT COMES THROUGH THE REGION SATURDAY MORNING INTO
EARLY SATURDAY AFTERNOON...UNCERTAINTY TAKES OVER WITH WHAT WILL
OCCUR SATURDAY NIGHT INTO SUNDAY. THE ONE THING THAT APPEARS TO
BE CERTAIN IS THAT COLDER AIR WILL ADVECT INTO THE REGION IN THE
LOW LEVELS BRINGING MUCH OF THE THERMAL PROFILE TO BELOW FREEZING
AND SUPPORTIVE OF SNOW BEING THE PRECIPITATION TYPE.
THE MAIN UNCERTAINTY LIES WITH THE DIFFERENCES BETWEEN THE US AND
NON-US MODEL SOLUTIONS WITH THE STRENGTH AND TRACK OF THE TROUGH.
BASED ON INPUT FROM HPC/S MODEL DIAGNOSTICS DESK...THE UNFAVORED
SOLUTION IS THE 25.00Z NAM/GFS AND 24.21Z SREF MEAN WHICH PRODUCE
A DEEPER...CLOSED OFF MID LEVEL LOW WHICH BRINGS THE DEFORMATION
AXIS THROUGH THE HEART OF THE FORECAST AREA. THESE SOLUTIONS WOULD
LIKELY LEAD TO AN ACCUMULATING SNOW ACROSS MUCH OF THE REGION.
THESE MODELS ALSO DEVELOPS A VERY TIGHT PRESSURE GRADIENT IN THE
LOW LEVEL COLD AIR ADVECTION POCKET ON THE SOUTHWEST SIDE OF THE
SURFACE LOW WHICH WOULD BRING GUSTS UP NEAR ADVISORY CRITERIA.
HOWEVER...AT THIS POINT THE FAVORED SOLUTION FOR SATURDAY NIGHT
INTO SUNDAY IS WITH THE 25.00Z ECMWF/UKMET/CANADIAN MODELS. THESE
FORMS OF GUIDANCE ALL SHOW A MUCH LESS AMPLIFIED...OPEN MID LEVEL
WAVE WITH HARDLY ANY SNOW COMING THROUGH SATURDAY NIGHT.
BASED ON THIS INPUT FROM HPC ...HAVE BACKED OFF ON THE PROBABILITY
FOR PRECIPITATION AND THE WIND GUSTS JUST A TAD ON SATURDAY NIGHT.
FOR ADDITIONAL INFORMATION ON THIS FAVORED TREND...PLEASE SEE THE
LATEST PMDHMD FROM HPC.
COLD AIR WILL REMAIN IN PLACE UNTIL MONDAY WHEN A BRIEF SHOT OF
LOW LEVEL WARM AIR ADVECTION COMES THROUGH THE REGION.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
301 AM CST FRI NOV 25 2011
NOT A WHOLE LOT OF CONFIDENCE GOING INTO THE EXTENDED PERIOD DUE
TO THE ISSUES THIS WEEKEND...BUT HAVE TRENDED TOWARD THE 25.00Z
ECMWF/GEM/UKMET FORECAST WHICH CUT OFF A MID LEVEL LOW ALONG THE
GULF COAST EARLY NEXT WEEK AND SLOWLY BRINGS IT TOWARD THE
NORTHEASTERN US INTO MID WEEK. THIS SETUP WILL KEEP THE REGION IN
A COOL NORTHWESTERLY FLOW ALOFT AND LIMIT ANY KIND OF WARMING
TRENDS. NOT MUCH IN THE WAY OF PRECIPITATION CHANCES EXCEPT FOR AN
OPEN MID LEVEL TROUGH THAT DIVES SOUTHEAST TOWARD THE GREAT LAKES
ON THURSDAY WHICH COULD BRING SOME PRECIPITATION WITH IT.
&&
.AVIATION...THROUGH 18Z SATURDAY
1147 AM CST FRI NOV 25 2011
STRATUS HAS MOVED IN FROM THE SOUTHWEST INTO BOTH TAF SITES...WITH
MVFR CEILINGS AT KLSE AND IFR CEILINGS AT KRST. THESE CEILINGS ARE
LIKELY TO PERSIST INTO EARLY THIS EVENING...AND THEN GRADUALLY
START FALLING WITH NOCTURNAL COOLING AND MORESO AFTER MIDNIGHT
WHEN RAIN IS FORECAST TO OCCUR. ANTICIPATING BOTH SITES AT IFR AT
08Z WITH LIFR CONDITIONS LIKELY AS WELL. VFR VISIBILITIES SHOULD
REMAIN THE RULE THROUGH THE EVENING...THOUGH CANNOT RULE OUT BRIEF
TIMES OF KRST DROPPING TO MVFR BEFORE THEN GIVEN THE 6SM VISIBILITY
AT 17Z. BETTER SHOT OF MVFR VISIBILITIES COMES AFTER 06Z TONIGHT
AND EVEN IFR VISIBILITIES TOWARDS 12Z WITH THE RAIN. THE RAIN THAT
IS FORECAST IS DUE TO A TROUGH OF LOW PRESSURE MOVING INTO THE TAF
SITES. PLAN ON THIS TROUGH TO MOVE THROUGH THE TAF SITES BETWEEN
12-15Z SATURDAY. IN ITS WAKE...PRECIPITATION WILL END ALLOWING
VISIBILITIES AND CEILINGS TO CLIMB. STILL HAVE CEILINGS ONLY
CLIMBING TO IFR AT BOTH TAF SITES LEADING UP TO 18Z...BUT IT
CERTAINLY POSSIBLE THAT THEY COULD REACH MVFR AROUND 18Z. IN
ADDITION...LOOK FOR WINDS TO TURN FROM SOUTHERLY TO WEST BEHIND
THE TROUGH. GUSTS TO 20 KT OR SO ARE POSSIBLE AT KRST AFTER 15Z
AND SHOULD INCREASE FURTHER AFTER 18Z WHEN COLD AIR FLOWS IN.
&&
.CLIMATE...FOR TODAY
301 AM CST FRI NOV 25 2011
RECORD HIGHEST LOWS MAY BE BROKEN TODAY AT BOTH ROCHESTER AND LA
CROSSE WITH TEMPERATURES THIS MORNING FAIRLY MILD IN THE UPPER 40S
TO AROUND 50. THE RECORD HIGHEST LOW TEMPERATURE FOR ROCHESTER
TODAY IS 37 FROM 1915. THE RECORD HIGHEST LOW TEMPERATURE FOR LA
CROSSE TODAY IS 42 IN 1998. FORECAST TEMPERATURES AT MIDNIGHT
TONIGHT ARE EXPECTED TO BE ABOVE THESE VALUES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
301 AM CST FRI NOV 25 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
CLIMATE...HALBACH