Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 11/23/11
AREA FORECAST DISCUSSION...UPDATE
NWS LITTLE ROCK AR
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 41 59 39 / 10 10 0 0
CAMDEN AR 60 45 64 42 / 10 10 0 0
HARRISON AR 50 38 59 38 / 0 10 0 0
HOT SPRINGS AR 59 43 62 41 / 10 10 0 0
LITTLE ROCK AR 60 43 61 41 / 10 10 0 0
MONTICELLO AR 63 46 64 42 / 10 10 0 0
MOUNT IDA AR 58 41 63 41 / 10 10 0 0
MOUNTAIN HOME AR 52 40 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 57 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...64
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
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 41 59 39 / 10 10 0 0
CAMDEN AR 60 45 64 42 / 10 10 0 0
HARRISON AR 50 38 59 38 / 0 10 0 0
HOT SPRINGS AR 59 43 62 41 / 10 10 0 0
LITTLE ROCK AR 60 43 61 41 / 10 10 0 0
MONTICELLO AR 63 46 64 42 / 10 10 0 0
MOUNT IDA AR 58 41 63 41 / 10 10 0 0
MOUNTAIN HOME AR 52 40 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 57 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...64
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
830 PM EST Tue Nov 22 2011
.UPDATE...
01Z water vapor and H4 RUC analysis showing longwave troughing
advancing eastward from the central CONUS toward the Atlantic coast.
Trough axis this mid evening extends from the southern Great Lakes
to the middle and southern MS valley. Broad swath of upper level
moisture ahead of this trough can be seen spreading northeast along
the northern Gulf Coast.
At the surface,
Our forecast area resides between a ridge of high pressure across
the FL peninsula/Eastern Gulf of Mexico and an approaching cold
front to the west. Southerly flow ahead of this front is providing a
warm and moist low level airmass for the region this evening.
Temperatures and even dewpoints are generally in the upper 60s to
lower 70s.
Tracking a broken line of convection now entering our far western
zones of SE AL and the Florida panhandle. Thus far, not seeing much
in the way of stronger storms (or even much lightning) associated
with this activity as it has advanced eastward this evening. Ahead
of this line, a scattering of showers associated with a broad WAA
regime are occurring across the western FL Big Bend into SW GA.
Deep layer synoptic lift ahead of the upper trough will continue to
overspread the region during the coming hours, keeping rain chances
in the forecast for our western zones and expanding the rain threat
further east with time. Looking at the latest few runs of the
RUC/HRRR, and also the latest local hi-res WRF-ARW run, do not see
much that would suggest a significant severe weather threat is
materializing for our area. Although the deep layer shear is
sufficient to support organized storms, the low level (0-1km) shear
and low level helicity parameters are very marginal until one gets
well north of Dothan and Albany. Can not rule out a few isolated
stronger storms during the next several hours (generally north of
the FL border), however at this time, do not anticipate a southward
expansion of the current TOR Watch in effect across portions of
central AL/central GA.
The cold front will advance into our western zones after midnight
with lingering showers/isolated storms ending with its passage
before sunrise. The front will then quickly exit through
SW/South-Central GA and the FL Big Bend during Wednesday morning.
Currently expecting showers to end in Albany/Tallahassee within a
couple hours of sunrise, and be exiting the Mayo/Cross City area by
around midday. A drier airmass will be filtering in from the NW
through the day in the wake of the front.
&&
.Aviation...
Several rounds of showers/isolated thunderstorms are expected
overnight in advance of a cold front. Low level moisture ahead of
this front will result in a gradual reduction in CIG heights through
the night, and a period of MVFR/IFR conditions appears likely for
all of the TAF sites after midnight into the first few daylight
hours. Brief MVFR/IFR vis conditions will also be possible
associated with any passing storms. The arrival of a drier airmass
during Wednesday will bring all terminals back to VFR conditions by
early afternoon.
&&
.MARINE...South and Southwest flow ahead of an approaching cold
front will occasionally approach cautionary levels through the
overnight. After the cold front passes Wednesday morning, winds
are expected to increase into the cautionary headline range for the
majority of the day.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 64 79 45 72 42 / 70 60 0 0 0
Panama City 64 75 48 68 49 / 70 50 0 0 0
Dothan 61 76 43 71 42 / 80 20 0 0 0
Albany 62 76 43 71 40 / 80 40 0 0 0
Valdosta 64 79 46 71 42 / 60 70 0 0 0
Cross City 64 80 49 72 42 / 40 70 0 0 0
Apalachicola 67 78 50 70 52 / 70 60 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
MROCZKA/CAMP
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
308 PM EST MON NOV 21 2011
...AREAS OF DENSE FOG POSSIBLE TONIGHT...
.CURRENTLY...SFC HIGH PRES IS SITUATED OVER SE GA AND TEMPS ARE IN
THE LOWER 80S INLAND AREAS. HAVE REACHED A NEW RECORD HIGH AT ALMA
AND TEMP AT 2 PM WAS 82...PRIOR RECORD 81 IN 1991. BROAD INVERTED
SFC TROUGHING SW-NE LOCATED FROM FL KEYS TO CENTRAL FL AND INTO THE
WRN ATLC. ONLY FEW-SCT CU OVER THE AREA AT THIS TIME. WATER VAPOR
AND RUC FIELDS SHOW DRIER MID-UPPER LEVEL AIR RESIDING OVER NE FL
AND WITH WEAK DISTURBANCES IN PREVAILING WLY FLOW IN THE MID LEVELS
AFFECTING SE GA. FURTHER UPSTREAM...STRONG MID/UPPER TROUGH IS
ACROSS THE W CENTRAL CONUS.
.SHORT TERM...
TONIGHT...AS THE UPSTREAM TROUGH SHIFTS EWD...MEAN LAYER RIDGE WILL
CONT WORKING EWD RESULTING CONTD WARM ADVECTION PATTERN. LOW LEVEL
MOISTURE WILL INCREASE AS WILL LOW LEVEL WINDS. LATE NIGHT
DECOUPLING AND LIGHT SFC WINDS WILL PROMOTE FOG/STRATUS DEVELOPMENT
WITH AREAS OF FOG (SOME OF IT DENSE) MAINLY INLAND. LOWS AGAIN THE
MID-UPPER 50S AND NEAR 60 COAST.
TUE...APPEARS THAT PSEUDO WARM FRONT WILL LIFT NWD THROUGH OUR AREA
WITH ISOLD LIGHT PRECIP POSSIBLE INLAND ZONES. RAIN CHANCES FAIRLY
MINIMAL AT THIS TIME AT 20%. WOULD GO A COUPLE OF DEG ABOVE GUIDANCE
BUT WITH CLOUDINESS WILL KEEP HIGHS WITHIN A DEG OR SO. TUE
NIGHT...MODELS SHOW MID/UPPER TROUGH MOVING THROUGH THE TN VALLEY
WITH ASSOCD FRONT MOVING TO NEAR NRN GA TO THE LOWER MS VALLEY.
PRECIP CHANCES EXPECTED TO INCREASE GRADUALLY WITH HIGHER POPS
AROUND 30% OVER THE NW ZONES AFT MIDNIGHT. TEMPS WILL SLOWLY FALL TO
THE LOWER 60S. LOW STRATUS AND PATCHY FOG EXPECTED.
WED...COLD FRONT WILL SHIFT SEWD THROUGH OUR AREA WITH THE BEST
CHANCES OVER THE NRN ZONES CLOSER TO THE STRONGER Q-VECTOR
CONVERGENCE PER GFS SOLUTION. ATTM...HAVE RAISED POPS SLIGHTLY WITH
60% OVER INLAND SE GA ATTM AND CHANCE POPS ELSEWHERE. THUNDERSTORM
CHANCES STILL LOOK FAIR TO GOOD GIVEN THE WEAK INSTABILITY AVAILABLE
BUT FAIRLY STRONG DEEP LAYER SHEAR AROUND 40-55 KT. WON`T RULE OUT A
FEW STRONG STORMS GIVEN THE LLVL JET NEAR 35-40 KT JET N OF I-10.
EXPECT TEMPS TO RESPOND AHEAD OF FRONT WITH UPPER 70S TO NEAR 80.
WED NIGHT...FRONT WILL PRESS SWD WITH SOME ISOLD LINGERING SHOWERS
POSSIBLE EARLY EVENING BEFORE HIGH PRES BUILDS IN ON NW-N WINDS.
THU...HIGH PRES BUILDS N OF THE AREA AND MOSTLY SUNNY TO PARTLY
SUNNY SKIES. HIGHS EXPECTED IN UPPER 60S TO LOWER 70S WITH BREEZY
NELY WINDS EXPECTED COASTAL COUNTIES.
.LONG TERM...
PREVIOUS EXTDD DISCUSSION...FRI AND SAT SFC HIGH PRES BUILDS
OFFSHORE AND ENE OF THE AREA WITH BREEZY ONSHORE FLOW MODERATING
TEMPS WITH HIGHS IN THE 70S AND MINS FRI NIGHT IN THE 50S. PRECIP
CHANCES INCREASE FROM THE WEST SAT NIGHT AS THE NEXT FRONTAL SYSTEM
APPROACHES. MODELS DIVERGE ON FROPA TIMING SUN...AS WELL AS TRAILING
SFC HIGH PRESSURE POSITION WHICH WILL INFLUENCE COLD AIR ADVECTION
PATTERN AND PERSISTENCE LOCALLY. LEANED TOWARD THE GFS ENSEMBLE
WHICH SHOWS BROAD LOW PRESSURE AND LOW RAIN CHANCES IMPACTING THE
CWA SUN...TRAILED BY CLEARING MON NIGHT AND SFC HIGH PRESSURE
BUILDING OVER THE AREA FROM THE WNW MON. EXTENDED RANGE MODELS ARE
INSISTENT ON A DEEP LONG WAVE TROUGH ASSOCIATED WITH NEXT WEEKENDS
FROPA...AND THIS TRANSLATES INTO ANOTHER COOL DOWN EARLY NEXT WEEK.
FOR MON MORNING HAVE LOWS FALLING INTO THE LOW 40S INLAND...WITH
HIGHS MON IN THE LOW/MID 60S.
&&
.AVIATION...
CONDITIONS WILL ONCE AGAIN BE FAVORABLE FOR FOG TONIGHT. LIKE THE
PAST FEW NIGHTS IT WILL LIKELY BE MORE OF A PATCHY DENSE FOG
EVENT...WHICH WILL MAKE IT DIFFICULT TO CAPTURE IN TAFS. WILL SHOW
A TREND TO IFR CONDITIONS BY LATE TONIGHT AT ALL BUT THE SSI
TERMINAL. OTHERWISE...VFR CONDITIONS WILL PREVAIL.
&&
.MARINE...
SURFACE RIDGE OVER THE AREA WILL KEEP LIGHT EASTERLY FLOW IN PLACE
THROUGH TUESDAY MORNING. THE RIDGE WILL SHIFT SOUTH OF THE AREA BY
TUESDAY EVENING AND WINDS WILL TURN TO THE SOUTH AND INCREASE TO
15 TO 20 KNOTS WITH SEAS BUILDING TO 4 TO 6 FEET. WINDS WILL
CONTINUE TO VEER ON WEDNESDAY AS A COLD FRONT CLOSES IN ON THE
AREA. THE FRONT IS PROGGED TO CLEAR THE AREA WEDNESDAY EVENING
WITH WINDS TURNING TO THE NORTHWEST AND INCREASING TO 20 TO 25
KNOTS. SCA HEADLINES WILL BE NEEDED BEGINNING WEDNESDAY NIGHT.
SEAS WILL ALSO BUILD...REACHING 6 TO 8 FEET BY THURSDAY NIGHT.
HIGH SEAS WILL LINGER INTO THE WEEKEND.
RIP CURRENTS: MODERATE RISK THROUGH TUESDAY DUE TO LINGERING
EASTERLY SWELLS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 56 81 62 76 / 0 20 30 60
SSI 60 74 63 75 / 10 10 30 50
JAX 57 81 61 79 / 10 20 20 50
SGJ 63 79 65 80 / 10 10 20 50
GNV 57 81 60 79 / 10 20 20 50
OCF 60 82 60 80 / 10 20 20 30
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/SHULER/
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1249 PM EST MON NOV 21 2011
.SYNOPSIS...
A PRESSURE RIDGE WILL BE CENTERED EAST AND SOUTH OF THE FORECAST
AREA THROUGH TUESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL
MOVE THROUGH THE AREA WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ZONAL FLOW OVER REGION TODAY. RUC MODEL SHOWS A WEAK SHORT WAVE
EXITING TO THE EAST BY LATE MORNING THEN NVA EARLY THIS AFTERNOON.
HOWEVER...ANOTHER WEAK RIPPLE MOVES MAINLY IN THE NORTHERN PART OF
THE AREA LATER THIS AFTERNOON. SO WILL KEEP A 20 PERCENT CHANCE OF
SHOWERS NORTH PART THIS AFTERNOON. WEAK ISENTROPIC LIFT THROUGHOUT
TODAY SHOULD HELP MAINTAIN SOME CLOUDINESS. WE WILL REMAIN IN THE
WARM AIR MASS WITH A PRESSURE RIDGE EAST AND SOUTH OF THE FORECAST
AREA. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
THE NAM AND GFS KEEP A WARM FRONT AND ASSOCIATED DEEPER MOISTURE
NORTH OF THE FORECAST AREA THROUGH TUESDAY. A COLD FRONT
APPROACHING FROM THE WEST TUESDAY NIGHT SHOULD MOVE THROUGH THE
FORECAST AREA WEDNESDAY. NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
WILL LIKELY OCCUR MAINLY ASSOCIATED WITH THE H85 JET AHEAD OF THE
FRONT. USED THE HIGHER NAM MOS POPS. THE NAM AND GFS INDICATE H85
WINDS OF 35 TO 40 KNOTS. SEVERE THUNDERSTORMS MAY OCCUR BECAUSE OF
THE STRONG SHEAR. THE MODELS SHOW THE JET AND ASSOCIATED MOISTURE
SHIFTING EAST OF THE FORECAST AREA BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE WEDNESDAY
NIGHT THROUGH SATURDAY. THE GFS SHOWS THE PRESSURE RIDGE EXTENDING
THROUGH THE FORECAST AREA FRIDAY. THE GFS ENSEMBLE MEANS INDICATE
THE COLDEST TEMPERATURES FRIDAY MORNING AND THIS APPEARS REASONABLE
BECAUSE OF THE STRONGEST RADIATIONAL COOLING. THE GFS SHOWS A STRONG
COLD FRONT MOVING INTO THE AREA SUNDAY. THE GFS ENSEMBLE MEAN
POPS SUPPORT POPS AROUND 30 PERCENT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WEAK HIGH PRESSURE REMAINS OVER THE AREA THIS AFTERNOON WITH WSW
FLOW ALOFT. EXPECT SOME WEAK RIPPLES IN THE UPPER FLOW TODAY WHICH
MAY TRIGGER A FEW SHOWERS ACROSS THE AREA DURING THE AFTERNOON
HOURS...MAINLY ACROSS THE NORTHERN CWA INTO NC. VFR CONDITIONS THIS
AFTERNOON...BUT GUIDANCE INDICATES DETERIORATING CONDITIONS
OVERNIGHT/TUESDAY MORNING. MODELS MAINTAIN THE FOG THREAT AFTER
22/00Z...SO HAVE INCLUDED MVFR FOG AT ALL TAF SITES FROM ABOUT
22/04Z ONWARD. WITH GUIDANCE SO PESSIMISTIC AND BUFKIT SHOWING
PLENTY OF LOW LEVEL MOISTURE/LIGHT WINDS...EXPECT A PERIOD OF
IFR/LIFR THROUGH 14Z. EXPECT VFR CONDITIONS TO RETURN AFTER 14Z.
EXTENDED AVIATION OUTLOOK...MVFR TO IFR CIGS/VSBYS POSSIBLE
WEDNESDAY MORNING ASSOCIATED WITH AN APPROACHING FRONTAL SYSTEM
FROM THE NORTHWEST.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1042 AM EST MON NOV 21 2011
.SYNOPSIS...
A PRESSURE RIDGE WILL BE CENTERED EAST AND SOUTH OF THE FORECAST
AREA THROUGH TUESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL
MOVE THROUGH THE AREA WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ZONAL FLOW OVER REGION TODAY. RUC MODEL SHOWS A WEAK SHORT WAVE
EXITING TO THE EAST BY LATE MORNING THEN NVA EARLY THIS AFTERNOON.
HOWEVER...ANOTHER WEAK RIPPLE MOVES MAINLY IN THE NORTHERN PART OF
THE AREA LATER THIS AFTERNOON. SO WILL KEEP A 20 PERCENT CHANCE OF
SHOWERS NORTH PART THIS AFTERNOON. WEAK ISENTROPIC LIFT THROUGHOUT
TODAY SHOULD HELP MAINTAIN SOME CLOUDINESS. WE WILL REMAIN IN THE
WARM AIR MASS WITH A PRESSURE RIDGE EAST AND SOUTH OF THE FORECAST
AREA. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
THE NAM AND GFS KEEP A WARM FRONT AND ASSOCIATED DEEPER MOISTURE
NORTH OF THE FORECAST AREA THROUGH TUESDAY. A COLD FRONT
APPROACHING FROM THE WEST TUESDAY NIGHT SHOULD MOVE THROUGH THE
FORECAST AREA WEDNESDAY. NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
WILL LIKELY OCCUR MAINLY ASSOCIATED WITH THE H85 JET AHEAD OF THE
FRONT. USED THE HIGHER NAM MOS POPS. THE NAM AND GFS INDICATE H85
WINDS OF 35 TO 40 KNOTS. SEVERE THUNDERSTORMS MAY OCCUR BECAUSE OF
THE STRONG SHEAR. THE MODELS SHOW THE JET AND ASSOCIATED MOISTURE
SHIFTING EAST OF THE FORECAST AREA BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE WEDNESDAY
NIGHT THROUGH SATURDAY. THE GFS SHOWS THE PRESSURE RIDGE EXTENDING
THROUGH THE FORECAST AREA FRIDAY. THE GFS ENSEMBLE MEANS INDICATE
THE COLDEST TEMPERATURES FRIDAY MORNING AND THIS APPEARS REASONABLE
BECAUSE OF THE STRONGEST RADIATIONAL COOLING. THE GFS SHOWS A STRONG
COLD FRONT MOVING INTO THE AREA SUNDAY. THE GFS ENSEMBLE MEAN
POPS SUPPORT POPS AROUND 30 PERCENT.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
WEAK HIGH PRESSURE REMAINS OVER THE AREA WITH WSW FLOW ALOFT. EXPECT
SOME WEAK RIPPLES IN THE UPPER FLOW TODAY WHICH MAY TRIGGER A FEW
SHOWERS ACROSS THE AREA DURING THE AFTERNOON HOURS. MAINLY VFR
CONDITIONS DURING TODAY. MODELS MAINTAIN THE FOG THREAT AFTER
22/00Z...SO HAVE INCLUDED MVFR FOG AT ALL TAF SITES FROM ABOUT
22/04Z ONWARD.
EXTENDED AVIATION OUTLOOK...MVFR TO IFR CIGS/VSBYS POSSIBLE
WEDNESDAY MORNING ASSOCIATED WITH AN APPROACHING FRONTAL SYSTEM
FROM THE NORTHWEST.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...07
NEAR TERM...07
SHORT TERM...07
LONG TERM...07
AVIATION...22
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
905 PM EST TUE NOV 22 2011
.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 701 PM EST TUE NOV 22 2011/
AVIATION...
00Z TAFS...WIDESPREAD RAIN WILL CONTINUE TO AFFECT THE TERMINALS
OVER THE NEXT FEW HOURS AS A STRONG UPPER LEVEL TROUGH CONTINUES
TO TRACK EASTWARD ACROSS THE SOUTHERN GREAT LAKES. A STRONG LEAD
VORT MAX PROGRESSING THROUGH NORTHEAST INDIANA WILL BRING A PERIOD
OF MODERATE RAIN TO KFWA OVER THE NEXT FEW HOURS. BY 02Z...MAIN
PRECIP AREA TO AFFECT TERMINALS WILL BE DEFORMATION BAND SETTING
UP ACROSS NORTHEAST ILLINOIS INTO NORTHWEST INDIANA AT 00Z.
THROUGH TIME...INTENSITY OF RAIN IN THIS DEFORMATION BAND SHOULD
BEGIN TO WANE AS THE UPPER TROUGH MOVES INTO OHIO. A PERIOD OF
HIGHER END IFR OR LOWER END MVFR CIGS ARE EXPECTED TO PERSIST
THROUGH MUCH OF THE NIGHT BEFORE SYNOPTIC SCALE SUBSIDENCE AND
LOW/MID LEVEL DRY AIR ADVECTION RESULT IN CLEARING TREND AFTER
09Z. DID INCLUDE TEMPO MVFR VSBY MENTION ACROSS KSBN WHERE
CLEARING IS EXPECTED TO OCCUR SHORTLY AFTER 09Z. RECENT RAINFALL
AND CLEARING SKIES MAY ALLOW FOR PATCHY FOG FORMATION...ALTHOUGH
SOME QUESTION AS TO THE DEGREE TO WHICH LOW LEVELS REMAIN MIXED.
GIVEN THIS UNCERTAINTY HAVE ONLY CARRIED AN MVFR MENTION AT THIS
TIME. QUIET AVIATION WEATHER IN STORE FOR WEDNESDAY WITH LIGHTER
NORTHWEST WINDS AND MAINLY CLEAR SKIES.
&&
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 5 PM EST WEDNESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...JT
AVIATION...MARSILI
UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
701 PM EST TUE NOV 22 2011
.AVIATION...
00Z TAFS...WIDESPREAD RAIN WILL CONTINUE TO AFFECT THE TERMINALS
OVER THE NEXT FEW HOURS AS A STRONG UPPER LEVEL TROUGH CONTINUES
TO TRACK EASTWARD ACROSS THE SOUTHERN GREAT LAKES. A STRONG LEAD
VORT MAX PROGRESSING THROUGH NORTHEAST INDIANA WILL BRING A PERIOD
OF MODERATE RAIN TO KFWA OVER THE NEXT FEW HOURS. BY 02Z...MAIN
PRECIP AREA TO AFFECT TERMINALS WILL BE DEFORMATION BAND SETTING
UP ACROSS NORTHEAST ILLINOIS INTO NORTHWEST INDIANA AT 00Z.
THROUGH TIME...INTENSITY OF RAIN IN THIS DEFORMATION BAND SHOULD
BEGIN TO WANE AS THE UPPER TROUGH MOVES INTO OHIO. A PERIOD OF
HIGHER END IFR OR LOWER END MVFR CIGS ARE EXPECTED TO PERSIST
THROUGH MUCH OF THE NIGHT BEFORE SYNOPTIC SCALE SUBSIDENCE AND
LOW/MID LEVEL DRY AIR ADVECTION RESULT IN CLEARING TREND AFTER
09Z. DID INCLUDE TEMPO MVFR VSBY MENTION ACROSS KSBN WHERE
CLEARING IS EXPECTED TO OCCUR SHORTLY AFTER 09Z. RECENT RAINFALL
AND CLEARING SKIES MAY ALLOW FOR PATCHY FOG FORMATION...ALTHOUGH
SOME QUESTION AS TO THE DEGREE TO WHICH LOW LEVELS REMAIN MIXED.
GIVEN THIS UNCERTAINTY HAVE ONLY CARRIED AN MVFR MENTION AT THIS
TIME. QUIET AVIATION WEATHER IN STORE FOR WEDNESDAY WITH LIGHTER
NORTHWEST WINDS AND MAINLY CLEAR SKIES.
&&
.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 5 PM EST WEDNESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...JT
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
304 PM EST MON NOV 21 2011
.SHORT TERM...
TONIGHT THROUGH TUESDAY NIGHT...
WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS DEPICTING SHORT WAVE
ENERGY EJECTING OUT OF THE BASE OF UPPER TROUGH ALONG SW US/MEX
BORDER THIS AFTERNOON. THIS WILL QUICKLY MOVE THROUGH THE MORE
PROGRESSIVE ZONAL FLOW EAST OF THE MISSISSIPPI AND RESULT IN SFC LOW
DEEPENING AND MOVING ALONG THE OHIO RIVER VALLEY ON TUESDAY.
FORECAST AREA WILL BE IN THE OVERRUNNING PRECIP NORTH OF THIS SYSTEM
MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS. PRONOUNCED
BACKING OF THE WINDS ALONG THE 300K THETA SFC WILL LEAD TO ENHANCED
ISENTROPIC ASCENT OVER THE AREA TUESDAY MORNING...BUT WILL TAKE SOME
TIME TO OVERCOME MID LEVEL DRYING...SO HAVE BACKED DOWN A BIT ON
POPS IN THE 12-18Z TIMEFRAME OVER THE NORTHERN HALF OF THE CWA.
ENTIRE COLUMN WILL THEN QUICKLY SATURATE EARLY TUESDAY AFTERNOON
LENDING CREDENCE TO A DEFINITE RAIN EVENT OVER ALL OF THE FORECAST
AREA TUESDAY AFTERNOON/EVENING. WHILE AXIS OF HEAVIEST PRECIP
EXPECTED TO BE SOUTH OF THE FORECAST AREA...SOUTHERN CWA COULD STILL
SEE IN EXCESS OF ONE INCH OF RAIN. SYSTEM TO EXIT THE AREA TUESDAY
NITE WITH JUST CHANCE POPS LEFT IN SE CWA AFTER MIDNIGHT. SOUTHERLY
TRACK OF SFC LOW WILL KEEP FCST AREA IN COOL EASTERLY FLOW AT LOW
LEVELS WHICH WILL HAMPER MIXING DOWN WAA ALOFT...HAVE CUT HIGHS TUE
FROM CURRENT FCST MORE TOWARD LATEST MOS GUIDANCE TO BETTER REFLECT
THIS THINKING.&&
.LONG TERM...
RIDGING SFC AND ALOFT TO BLD IN ACRS THE CWA TO START THE PD ON WED
BEHIND DEPARTING SHRT TERM SYS AND APCHG DEEP LYRD TROUGH CROSSING
THE ROCKIES FRI. BIGGEST CHG WAS TO BUMP TEMPS CONSIDERABLY THU-SAT
AND AGAINST PREVAILING ALLBLEND PROCEDURE WHICH AGAIN TDA WAS BIASED
WET AND COOL.
OTHERWISE PROBS ABOUND W/POTENTIAL PHASING ISSUED RELEGATED TO SPLIT
STREAM FLW ACRS THE WRN US LT WEEK AND NXT WEEKEND. GREATER
CONTINUITY LIES W/OP GFS AND ECM/GFS ENSEMBLES AND HAVE GENERALLY
FOLLOWED SUGGESTION OF MODEL CONSENSUS THIS AFTN ESP IN LIGHT OF
MORE AGREEABLE SLOWING TREND SEEN IN SUBSEQUENT MODEL INTERATIONS
SINCE YDA AND DISCUSSED YDA. THUS DROPPED FRI NIGHT PCPN MENTION
ALTOGETHER AND NOTCHED W-E GRADIENT FURTHER SAT. REMAINDER ON TRACK
ATTM TIED TO PROGGED DEEP MID MS VALLEY CUTOFF LT NXT WEEKEND YET
STILL HIGHLY UNCERTAIN W/CONSIDERABLE MODEL SPREAD ALOFT NOT TO
MENTION VARIOUS PLACEMENT VAGARIES. THUS WILL HOLD SHORT OF ANY
PERCEIVED LIKELY MENTION AT THIS TIME IN LIGHT OF THE UNCERTAINTY.
&&
.AVIATION...
AMPLE BOUNDARY LAYER/LOW LEVEL MOISTURE REMAINING TRAPPED UNDER
850MB INVERSION AND AS A RESULT MVFR CIGS HAVE PERSISTED AT BOTH TAF
SITES INTO THIS AFTERNOON. VISIBLE SATELLITE SHOWING NORTHERN EDGE
OF LOW CLOUDS ALONG IN/MI BORDER...STILL HOLDING OUT SOME HOPE FOR
SCATTERING OUT AT KSBN LATER IN THE AFTERNOON BUT PLAN TO JUST KEEP
KFWA LOCKED IN REMAINDER OF THE TAF PERIOD. RAIN EXPECTED TO MOVE IN
TUESDAY FROM SOUTH TO NORTH. WILL INTRODUCE TO KFWA TOWARD END OF
THIS TAF CYCLE BUT HOLD OFF ON KSBN TILL NEXT ISSUANCE. SFC LOW TO
TRACK SOUTH OF BOTH TAF SITES KEEPING EASTERLY FLOW IN PLACE THROUGH
THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...T
AVIATION...LOGSDON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1056 AM CST MON NOV 21 2011
.UPDATE...
12Z UA ANALYSIS HAS A MESO HIGH AT 850MB OVER THE CWFA WHICH
HELPED TO BREAK UP THE CLOUDS ACROSS THE AREA. SATELLITE TRENDS
SHOW THE LOW CLOUDS GENERALLY ALONG THE EDGES OF THE WEST AND
SOUTHERN PARTS OF THE CWFA WITH HIGH LEVEL CI/CS MOVING IN FROM
THE SOUTH AND WEST.
RUC TRENDS SUGGEST FILTERED SUN DEVELOPING THIS AFTERNOON AS THE
CS/CI SHIELD BUILDS INTO THE AREA. THE ADDITIONAL SUN IS ALSO
PUSHING TEMPERATURES CLOSER TO THE MAX TEMPERATURES AND
ADJUSTMENTS HAVE BEEN MADE AS WELL. THOSE AREAS THAT ALREADY HAVE
THE LOW CLOUDS PRESENT WILL PROBABLY NOT SEE MUCH IN THE WAY OF
ADDITIONAL RISE TODAY.
AN UPDATE TO THE FCST REFLECTING ALL THIS HAS BEEN SENT.
..08..
&&
.AVIATION...
A MESO HIGH IS CREATING WEAK DOWNWARD MOTION THAT IS PREVENTING
THE MVFR CIGS FM MOVG INTO EASTERN IOWA/NORTHERN ILLINOIS.
SATELLITE ALONG WITH RUC TRENDS INDICATE HIGH LEVEL CLOUDS WILL
OVERSPREAD THE AREA THROUGH 20Z/21. RUC IS SUGGESTING A POSSIBLE
SCT-BKN CLOUD DECK DVLPG AT THE 6-9KFT AGL AFT 18Z/21. IF THE RUC
TRENDS ARE CORRECT...MVFR CIGS OF 2-3KFT AGL DVLPG AT KBRL AFT
00Z/22. KCID/KDBQ/KMLI MAY SEE MVFR CIGS OF 2-3KFT AGL AFT 06Z/22.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
532 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...
STRATUS HAS JUST CLEARED KMHK AND WILL CLEAR KTOP AND KFOE IN THE
NEXT 2 TO 3 HRS. HOWEVER...THE MAIN AVIATION CONCERN OVERNIGHT
WILL BE FOR THE DEVELOPMENT OF DENSE FOG. CLEARING SKIES...LIGHT
WINDS AND AMPLE MOISTURE NEAR THE SURFACE FROM RECENT
RAINS WILL PROVIDE THE INGREDIENTS FOR A DENSE FOG SETUP
OVERNIGHT. MODELS SOUNDINGS ARE INDICATING A STRONG INVERSION WILL
OCCUR AROUND MIDNIGHT TONIGHT AND HAVE LOWERED VISIBILITIES DOWN TO
LIFR DURING THIS TIME WITH ALL THE INGREDIENTS IN PLACE FOR DENSE
FOG FORMATION. FOG SHOULD DISSIPATE AROUND MID-MORNING TOMORROW.
ANDERSON
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
312 PM CST MON NOV 21 2011
.DISCUSSION...
20Z WATER VAPOR IMAGERY SHOWS THE UPPER LEVEL LOW MOVING ACROSS THE
FOUR CORNERS REGION CAUSING SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS WESTERN OK AND THE TX PANHANDLE. SURFACE OBS SHOW RIDGING
STILL IN PLACE ACROSS THE UPPER MIDWEST AND NOSING INTO NORTHEAST
KS.
FOR TONIGHT AND TUESDAY...PRECIPITATION IS EXPECTED TO BECOME MORE
WIDESPREAD AS THE UPPER LEVEL WAVE MOVES CLOSER AND UPPER DIFFLUENCE
INCREASES ALONG WITH INCREASING MOISTURE ADVECTION. THE MAIN CONCERN
IS POTENTIAL FOR A BRIEF PERIOD OF FREEZING RAIN ACROSS FAR NORTH
CENTRAL KS. MOS GUIDANCE WANTS TO TAKE LOWS BELOW FREEZING...HOWEVER
FORECAST SOUNDINGS FROM THE NAM AND GFS BOTH SHOW SFC TEMPS
REMAINING IN THE MIDDLE AND UPPER 30S. WITH OVERCAST SKIES
ANTICIPATED TO PERSIST AND MODELS SHOWING WEAK TEMP ADVECTION IF ANY
AT ALL...HAVE FAVORED THE MORE MILD TEMP FORECAST FROM THE FORECAST
SOUNDINGS. THEREFORE HAVE CONTINUED WITH A FORECAST OF ALL RAIN. MID
LEVEL LAPSE RATES CONTINUE TO SUGGEST SOME ISOLATED THUNDER WITH THE
PRECIP AS WELL. RAIN SHOULD COME TO AN END DURING THE DAY TUESDAY AS
THE UPPER LEVEL WAVE MOVES EAST AND SUBSIDENCE INCREASES. HIGHS ARE
FORECAST TO RANGE FROM THE UPPER 40S IN THE EAST WITH CLOUDS MOST OF
THE DAY AND LOWER 50S WEST WHERE SOME SUNSHINE SHOULD BREAK OUT BY
THE AFTERNOON.
WOLTERS
TUESDAY NIGHT THROUGH THANKSGIVING DAY...
MODELS CONTINUE IN EXCELLENT AGREEMENT THAT THE INITIAL SHORTWAVE
TROUGH WILL MOVE RAPIDLY EASTWARD INTO THE OH RIVER VALLEY TUESDAY
EVENING AS UPPER LEVEL RIDGING INCREASES ACROSS THE HIGH PLAINS.
THIS WILL ALLOW FOR WARM AIR ADVECTION AT 850MB TO BEGIN ACROSS THE
WESTERN COUNTY WARNING AREA (CWA) IN THE 06Z-12Z WED. TIMEFRAME THEN
EASTWARD DURING THE DAY WEDNESDAY ACROSS THE REMAINDER OF THE CWA.
HOWEVER...SINCE TUESDAY NIGHT SFC WINDS WILL BE FAIRLY LIGHT AND
SKIES CLEAR...SHOULD SEE MORNING LOWS IN THE UPPER 20S TO LOWER 30S.
ON THE OTHER HAND...THE CONTINUED WARM AIR ADVECTION AND BETTER
MIXING DURING THE DAY WITH ABUNDANT SUNSHINE SHOULD PUSH HIGHS INTO
THE MIDDLE 50S FAR NORTHEAST TO THE UPPER 50S TO LOWER 60S ELSEWHERE.
THE UPPER LEVEL RIDGE WILL THEN PUSH EASTWARD ACROSS THE CENTRAL
PLAINS WEDNESDAY NIGHT. THE UPPER FLOW OVER THE CWA WILL THEN BECOME
SOUTHWESTERLY ON THANKSGIVING DAY AS THE NEXT SHORTWAVE TROUGH
APPROACHES THE SOUTHERN ROCKIES. THIS WILL KEEP UNSEASONABLY MILD
AIR IN PLACE ACROSS THE AREA WEDNESDAY THROUGH THANKSGIVING DAY.
AFTER LOWS IN THE UPPER 30S TO LOWER 40S...GUSTY SOUTH WINDS AND
MOSTLY SUNNY SKIES WILL ALLOW FOR HIGHS ON THANKSGIVING DAY TO TOP
OUT IN THE LOW TO MIDDLE 60S. 63
EXTENDED FORECAST (THURSDAY NIGHT THROUGH MONDAY)
FRIDAY AN UPPER LEVEL TROUGH WILL MOVE OUT OF THE ROCKY MOUNTAINS
INTO THE CENTRAL PLAINS BRINGING A SURFACE COLD FRONT THROUGH KANSAS
ON FRIDAY. THE LATEST 12Z ECMWF HAS NOW TRENDED TOWARDS THE GFS WITH
A MORE PROGRESSIVE SYSTEM MOVING THROUGH THE CENTRAL PLAINS. THERE
WILL BE ENOUGH LIFT AND MOISTURE RETURN AHEAD OF THE FRONT FOR
SHOWERS FRIDAY AFTERNOON INTO SATURDAY MORNING. MODELS ARE SHOWING A
MINIMAL AMOUNT OF ELEVATED INSTABILITY AHEAD OF THE FRONT AND A FEW
ISOLATED THUNDERSTORMS COULD BE POSSIBLE FRIDAY AFTERNOON. THE ECMWF
IS THE SLOWEST OF ALL THE MODELS BUT STILL BRINGS THE COLD FRONT
TROUGH THE CWA BY EARLY MONDAY MORNING.
MODELS THEN CLOSE OFF AN UPPER LEVEL LOW OVER THE MID MISSISSIPPI
RIVER VALLEY LATE NEXT WEEKEND AND EARLY NEXT WEEK. THIS WILL ALLOW
FOR COLD AIR ADVECTION TO CONTINUE OVER THE CENTRAL PLAINS ON THE
WESTERN SIDE OF THE UPPER LEVEL LOW. MODELS ARE INDICATING 850MB
TEMPERATURES OF -7 TO -9 CELSIUS ON SUNDAY AND INTO MONDAY.
NORTHWEST WINDS WILL ADVECT COLD AIR IN ALL THE WAY FROM SOUTHERN
CANADA DOWN INTO THE WESTERN GULF OF MEXICO. THEREFORE...DECIDED TO
DROP TEMPERATURES A FEW DEGREES BELOW GUIDANCE AFTER THE FRONT
PASSAGE FOR LATE NEXT WEEKEND INTO EARLY NEXT WEEK.
ANDERSON
&&
.AVIATION...
LATEST RUC AND NAM RH PROGS ARE TRYING TO KEEP THE MVFR CIGS IN
THROUGH THE AFTERNOON. DO NOT SEE ANY SUBSIDENCE MOVING IN THIS
AFTERNOON AND AREA OBS ARE ALL BELOW 3 KFT. THEREFORE WILL GO WITH
PERSISTENCE REGARDING THE CIGS THIS AFTERNOON. THINK THAT IF
ANYTHING THE CIGS COULD GRADUALLY IMPROVE AS THE BOUNDARY LAYER
DEEPENS FROM LIMITED DIURNAL HEATING. PRECIP AND IFR CIGS LOOK TO
MOVE INTO THE TERMINALS LATE TONIGHT. IF MODEL PROGS OF PRECIP
INTENSITY ARE CORRECT...VSBY COULD ALSO BECOME IFR WITH MODERATE OR
BRIEF HEAVY RAINFALL. AT THIS POINT THINK TEMPS WILL REMAIN IN THE
MID 30S OVERNIGHT...KEEPING PRECIP IN LIQUID FORM.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS DODGE CITY KS
1156 AM CST MON NOV 21 2011
.AVIATION...
FOR THE 18Z TAF ISSUANCE......LOW CLOUDS SLOW TO ERODE EARLIER
THIS MORNING AS HIGH CLOUDS CONTINUE TO THICKEN ACROSS THE AREA.
DO EXPECTED IFR/MVFR CONDITIONS TO GIVE WAY TO VFR CONDITIONS
WITHIN THE NEXT HOUR...HOWEVER AS LOW LEVEL MOISTURE SPREADS INTO
SOUTHWEST KANSAS THIS EVENING AHEAD OF A 400MB PRESSURE ANOMALY DO
ANTICIPATE A RETURN OF AT LEAST MVFR CIGS BY EARLY EVENING. IN
ADDITION TO THE LOWER CIGS EARLY TONIGHT THERE WILL BE INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS....ESPECIALLY AT DDC AND
HYS. BASED ON THE LOCATION OF THE 300MB JET AND 400MB PV ANOMALY WILL
INTRODUCE A PREVAILING GROUP OF PRECIPITATION AT DDC AND HYS EARLY
TONIGHT. AT GCK THE PROBABILITY WILL BE LESS BUT WILL INSERT A
PROB30 GROUP HERE. WINDS OVER THE NEXT 6 TO 9HOURS WILL BE
SOUTHEAST AT 10KTS OR LESS THROUGH EARLY TONIGHT.
AFTER MIDNIGHT THESE SOUTH/SOUTHEAST WINDS WILL BECOME NORTHWEST AS
PRECIPITATION BEGINS TO END. THE LOWER LEVELS BETWEEN 06Z AND 12Z
WILL SATURATE AND IFR/LIFR CIGS/VSBYS ARE EXPECTED TO DEVELOP. WILL
THEREFORE INTRODUCE IFR CONDITIONS AT ALL TAF SITES BY 09Z. -RB
&&
PREV DISCUSSION... /ISSUED 311 AM CST MON NOV 21 2011/
SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1126 AM CST MON NOV 21 2011
.AVIATION...
FOR THE 18Z TAF ISSUANCE......LOW CLOUDS SLOW TO ERODE EARLIER
THIS MORNING AS HIGH CLOUDS CONTINUE TO THICKEN ACROSS THE AREA.
DO EXPECTED IFR/MVFR CONDITIONS TO GIVE WAY TO VFR CONDITIONS
WITHIN THE NEXT HOUR...HOWEVER AS LOW LEVEL MOISTURE SPREADS INTO
SOUTHWEST KANSAS THIS EVENING AHEAD OF A 400MB PRESSURE ANOMALY DO
ANTICIPATE A RETURN OF AT LEAST MVFR CIGS BY EARLY EVENING. IN
ADDITION TO THE LOWER CIGS EARLY TONIGHT THERE WILL BE INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS....ESPECIALLY AT DDC AND
HYS. BASED ON THE LOCATION OF THE 300MB JET AND 400MB PV ANOMALY.
AS A RESULT WILL INTRODUCE A PREVAILING GROUP OF PRECIPITATION AT
DDC AND HYS EARLY TONIGHT. AT GCK THE PROBABILITY WILL BE LESS BUT
WILL INSERT A PROB30 GROUP HERE. WINDS OVER THE NEXT 6 TO 9HOURS
WILL BE SOUTHEAST AT 10KTS OR LESS THROUGH EARLY TONIGHT.
AFTER MIDNIGHT THESE SOUTH/SOUTHEAST WINDS WILL BECOME NORTHWEST AS
PRECIPITATION BEGINS TO END. THE LOWER LEVELS BETWEEN 06Z AND 12Z
WILL SATURATE AND IFR/LIFR CIGS/VSBYS ARE EXPECTED TO DEVELOP. WILL
THEREFORE INTRODUCE IFR CONDITIONS AT ALL TAF SITES BY 09Z. -RB
&&
PREV DISCUSSION... /ISSUED 311 AM CST MON NOV 21 2011/
SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1114 AM CST MON NOV 21 2011
...AVIATION UPDATE...
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
LATEST RUC AND NAM RH PROGS ARE TRYING TO KEEP THE MVFR CIGS IN
THROUGH THE AFTERNOON. DO NOT SEE ANY SUBSIDENCE MOVING IN THIS
AFTERNOON AND AREA OBS ARE ALL BELOW 3 KFT. THEREFORE WILL GO WITH
PERSISTENCE REGARDING THE CIGS THIS AFTERNOON. THINK THAT IF
ANYTHING THE CIGS COULD GRADUALLY IMPROVE AS THE BOUNDARY LAYER
DEEPENS FROM LIMITED DIURNAL HEATING. PRECIP AND IFR CIGS LOOK TO
MOVE INTO THE TERMINALS LATE TONIGHT. IF MODEL PROGS OF PRECIP
INTENSITY ARE CORRECT...VSBY COULD ALSO BECOME IFR WITH MODERATE OR
BRIEF HEAVY RAINFALL. AT THIS POINT THINK TEMPS WILL REMAIN IN THE
MID 30S OVERNIGHT...KEEPING PRECIP IN LIQUID FORM.
WOLTERS
&&
.PREV DISCUSSION... /352 AM CST MON NOV 21 2011/
LOW STRATUS HAS WORKED ITS WAY NORTHWARD THROUGH THE EARLY MORNING
HOURS TODAY INTO NORTH CENTRAL KANSAS AND SOUTHEAST NEBRASKA LEAVING
THE CWA ENVELOPED IN CLOUDS. TEMPERATURES REMAIN ABOVE FREEZING IN
MOST LOCATIONS.
UPPER TROUGH WAS MOVING ACROSS NEVADA AND CALIFORNIA AT 08Z WITH
MOISTURE STREAMING OFF THE EASTERN PACIFIC ACROSS THE SOUTHERN
PLAINS AND SOUTHERN KANSAS. TEMPERATURES TODAY SHOULD RISE INTO THE
LOW AND MID 40S WITH SOME WARM ADVECTION AND A FEW BREAKS IN THE
CLOUDS. SOME VERY LIGHT DRIZZLE/MIST OCCURRING ACROSS EAST CENTRAL
KANSAS AND WILL CONTINUE INTO MID MORNING. WITH TEMPERATURES AT
OR BELOW FREEZING IN SOME AREAS WILL ALSO MENTION SOME FREEZING
DRIZZLE AS WELL.
THE UPPER LOW WILL MOVE EAST INTO NEW MEXICO TODAY WITH INCREASING
MOISTURE ADVECTION ACROSS ALONG WITH ISENTROPIC LIFT OVER THE
FRONTAL BOUNDARY IN NORTH TEXAS DEVELOPING SOME SHOWERS AND A FEW
THUNDERSTORMS AS FAR NORTH AS SOUTHERN KANSAS THIS AFTERNOON. MODELS
NOW KEEP BETTER CHANCES SOUTH OF THE FORECAST AREA AND HAVE GONE DRY
SOUTH OF INTERSTATE 35.
TONIGHT THE UPPER TROUGH WILL SWING NORTHEAST OUT OF THE ROCKIES
WITH INCREASING FORCING FOR ASCENT ACROSS EASTERN KANSAS THROUGH THE
EVENING AND OVERNIGHT HOURS. GOOD MOISTURE FLUX INTO THE
AREA...FRONTOGENESIS...COUPLED JET STRUCTURE ALL POINT TO VERY HIGH
PROBABILITY OF SHOWERS AND ISOLATED THUNDER FOR MUCH OF THE CWA.
HIGHEST POPS WILL BE GENERALLY SOUTH OF INTERSTATE 70. FORECAST
SOUNDINGS ACROSS NORTH CENTRAL KANSAS DO NOT SHOW FREEZING RAIN
FORMING AND HAVE REMOVED IT FROM THE FORECAST...BUT THIS WILL NEED
TO BE MONITORED WITH LATER MODEL RUNS. THE UPPER TROUGH MOVES EAST
INTO ILLINOIS ON TUESDAY. HAVE PRECIPITATION ENDING DURING THE DAY
FROM WEST TO EAST AS THE UPPER LEVEL DEFORMATION AXIS MOVES EAST.
HIGHS TUESDAY WILL ONLY TOP OUT IN THE 40S WITH THE COOLEST TEMPS IN
THE NORTHEAST CORNER.
MID WEEK STILL LOOKING NICE WITH RIDGE BUILDING INTO THE CENTRAL
PLAINS FOR THANKSGIVING DAY BEFORE GIVING WAY TO THE NEXT UPPER
TROUGH MOVING INTO THE ROCKIES THURSDAY NIGHT AND INTO THE PLAINS ON
FRIDAY. FRONTAL BOUNDARY FORECAST TO MOVES ACROSS KANSAS WITH
ANOTHER SHOT OF SHOWERS AND A FEW THUNDERSTORMS ACROSS CENTRAL AND
EASTERN KANSAS. GFS BEEN FAIRLY CONSISTENT MOVING THE TROUGH THROUGH
THE PLAINS FRIDAY AND SATURDAY. LATEST RUN OF THE 00Z ECMWF IS
SLOWER AND FURTHER SOUTH WITH THE UPPER LOW AND HAS MORE ENERGY
MOVING ACROSS THE NORTHERN PLAINS. MAINTAINED EARLIER MODEL
CONSENSUS WITH CHANCE POPS ACROSS THE CWA FOR FRIDAY AND FRIDAY
NIGHT THEN DIMINISHING CHANCES ON SATURDAY. 00Z ECMWF MOVES THE
NORTHERN PLAINS THROUGH THROUGH EASTERN KANSAS WHILE CUTTING OFF THE
LOW OVER THE SOUTHERN PLAINS AND RETROGRESSING IT SOUTHWEST TO THE
WEST COAST OF MEXICO BY 00Z MONDAY. UPSHOT HAVE KEPT SUNDAY DRY AS
PRIOR FORECAST.
53
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
518 AM CST MON NOV 21 2011
.UPDATE...
.AVIATION /FOR THE 12Z TAF ISSUANCE/
LIGHT AND VARIABLE WINDS WILL PERSIST THROUGH ABOUT 14-15 UTC THIS
MORNING, BEFORE DIURNAL HEATING AIDS THE DEVELOPMENT OF A PRESSURE
GRADIENT AND WINDS BECOME LIGHT SOUTHEASTERLY. SURFACE WINDS WILL
REMAIN IN THE 5-10 KNOT RANGE THROUGH THE DAY AND SLOWLY BACK TO THE
NORTH THROUGH MIDNIGHT. SLOW BOUNDARY LAYER MOISTURE ADVECTION IS
ANTICIPATED LATE IN THE PERIOD AS WELL FROM AN AIRMASS OVER OKLAHOMA
MARKED BY 30 TO 40 DEGREE DEW POINTS. WEAK LARGE SCALE ASCENT FROM
AND APPROACHING WESTERN WAVE WILL WORK WITH THIS MOISTURE TO DEVELOP
SHOWERS ACROSS THE EASTERN PORTION OF THE AREA AS EARLY AS 00-03
UTC.
&&
.PREV DISCUSSION... /ISSUED 311 AM CST MON NOV 21 2011/
SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN99/99/99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
311 AM CST MON NOV 21 2011
.SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
&&
.DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN25/33
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1139 PM CST SUN NOV 20 2011
...UPDATE TO AVIATION...
.DISCUSSION...
SURFACE RIDGING AND CLOUD COVER HAVE PREVENT TEMPS FROM WARMING UP
MUCH THIS AFTERNOON. 20Z SURFACE OBS CONTINUE TO SHOW COLD AIR
ADVECTING FROM THE NORTH WITH THE CENTER OF THE RIDGE OVER SOUTHERN
MN. ALOFT...WATER VAPOR SHOWS A CLOSED LOW OVER THE CA COAST AND
PROFILER DATA INDICATES A FAST SOUTHWEST FLOW OVER THE FORECAST AREA
WITH NO OBVIOUS WAVE WITHIN THE FLOW. HOWEVER THE RUC AND NAM
INDICATE A WEAK WAVE AT 700 MB MOVING ACROSS NORTHEAST KANSAS LATE
THIS AFTERNOON AND THIS EVENING. THIS MAY BE THE CAUSE OF THE
ENHANCED CLOUD COVER AND WEAK ECHOS ON RADAR ACROSS WESTERN KS.
THINK THAT THIS WILL NOT AMOUNT TO MUCH FOR TONIGHT DUE TO MID LEVEL
DRY AIR. MODELS SHOW THIS PASSING EAST WITH GENERAL SUBSIDENCE
TAKING OVER FOR MUCH OF THE NIGHT. ADDITIONALLY ISENTROPIC SURFACES
ARE NOT SHOWING MUCH LIFT EITHER. THEREFORE WILL CONTINUE WITH A DRY
FORECAST. CLOUD COVER COULD BE A LITTLE TRICKY TONIGHT AND HAVE A
LARGE EFFECT ON MIN TEMPS. THERE IS A GENERAL CONSENSUS THAT THE LOW
LEVEL RH OVER SOUTHERN MO AND SOUTHEAST KS WILL LIFT NORTH THROUGH
NORTHEAST KS OVERNIGHT. MEANWHILE SKIES COULD BECOME MOSTLY CLEAR
OVER CENTRAL KS. WITH THIS IN MIND HAVE DROPPED LOWS INTO THE LOWER
20S FROM MHK WEST AND LEFT LOWS IN THE LOWER 30S OVER FAR EASTERN KS
WHERE LOW CLOUDS ARE LIKELY TO HANG IN A LITTLE LONGER. FOR MONDAY
THINK TEMPS WILL WARM INTO THE MID 40S DUE TO NEUTRAL TEMP ADVECTION
AND SOME INSOLATION DURING THE DAY. MID LEVEL MOISTURE IS EXPECTED
TO BEGIN ADVECTING NORTH BY MONDAY AFTERNOON AS THE CLOSED LOW ON
THE WEST COAST MAKES ITS WAY OVER THE SOUTHERN ROCKIES. HAVE
INCLUDED SOME SLIGHT CHANCE POPS SOUTH OF I-70 DURING THE AFTERNOON
BECAUSE OF THIS.
WOLTERS
UPPER WAVE CONTINUES EAST AND NORTHEAST WHILE DEEPENING MONDAY
NIGHT. UPPER JET STREAKS FLANKING THE AREA TO THE NORTHEAST AND
SOUTHWEST INTO THE EVENING WITH DRY SLOT WORKING THROUGH SOUTHERN
KANSAS AND SOMEWHAT OF A WEAK TROWAL POKING INTO NORTHEAST KANSAS.
THERE REMAINS SOME DIFFERENCES ON THE TIMING OF THE SYSTEM WITH THE
12Z NAM ON THE FASTER END...BUT STILL APPEARS LATE EVENING THROUGH
EARLY MORNING TUESDAY WILL BE ON THE WET SIDE. DRY SLOT WILL HELP
AID CONVECTIVE CHANCES AND INSTABILITY STILL ENOUGH FOR THUNDER
INCLUSION FOR MUCH OF THE AREA. ALSO SOME CONCERN FOR FREEZING
PRECIP LATE IN THE EVENT AS SURFACE LOW PRESSURE MOVES THROUGH
SOUTHERN MISSOURI AND NORTH WINDS TAKE HOLD. WILL INTRODUCE A
FREEZING RAIN MENTION IN THE NORTHWEST. TUESDAY AFTERNOON AND NIGHT
BRING RAPIDLY IMPROVING CONDITIONS AS UPPER RIDGING BUILDS IN.
AIRMASS BEHIND THE SYSTEM NOT TERRIBLY COLD WITH DOWNSLOPE WINDS TO
THE NORTHWEST SO HIGHS SHOULD STILL REACH THE LOWER 50S TUESDAY AND
ON INTO THE UPPER 50S WEDNESDAY UNDER CLEAR SKIES AND INCREASING
SOUTH WINDS.
65
EXTENDED FORECAST (WEDNESDAY NIGHT THROUGH SUNDAY)
SOUTHERLY FLOW...WARM AIR ADVECTION AND UPPER LEVEL RIDGING WILL
RETURN TO THE CENTRAL U.S. ON THANKSGIVING DAY. HIGH TEMPERATURES
ARE EXPECTED TO QUICKLY REBOUND INTO THE LOW 60S. SOUTH WINDS WILL
BE STRONG AND GUSTY ON THANKSGIVING DAY WITH A STRONG PRESSURE
GRADIENT BETWEEN A SURFACE HIGH OVER THE SOUTHEASTERN U.S. AND
SURFACE LOW FORMING ALONG THE ROCKY MOUNTAINS. MODELS ARE INDICATING
A LONGWAVE TROUGH WILL MOVE OUT OF THE ROCKY MOUNTAINS ON FRIDAY
ALONG WITH THE SURFACE LOW AND COLD FRONT. ENOUGH ELEVATED
INSTABILITY WILL EXIST AHEAD OF THE APPROACHING FRONT FOR A FEW
THUNDERSTORMS DURING THE DAY ON FRIDAY.
MODELS QUICKLY DIVERGE INTO NEXT WEEKEND. THE OPERATIONAL GFS AND
DGEX BRING THE COLD FRONT THROUGH THE CWA FRIDAY NIGHT AND THEN
CLOSE OFF AN UPPER LEVEL LOW OVER THE MID-MISSISSIPPI RIVER VALLEY.
THE 12Z ECMWF BRINGS THE FRONT THROUGH THE CWA SATURDAY MORNING BUT
THEN CLOSES THE UPPER LEVEL LOW OFF IN NORTHEASTERN OKLAHOMA. THE
ECMWF SOLUTION WOULD KEEP PRECIPITATION CHANCES IN THE FORECAST FOR
THE MAJORITY OF HOLIDAY WEEKEND. FOR THE FORECAST HAVE FAVORED THE
MORE PROGRESSIVE SOLUTIONS OF THE GFS AND DGEX WITH MANY OF THE GFS
ENSEMBLES INDICATING A MORE PROGRESSIVE UPPER LEVEL WAVE.
ANDERSON
&&
.AVIATION...
MVFR STRATUS WILL CONTINUE ACROSS KTOP AND KFOE THROUGH 15Z
MONDAY...WITH CEILINGS OF 1200 TO 1600 FEET. KMHK MAY REMAIN AT OR
ABOVE VFR CEILINGS THROUGH THE NIGHT...THOUGH THEY MAY DROP BELOW
3,000 FEET AT TIMES DURING THE NIGHT. THE LOWER STRATUS SHOULD MIX
OUT BY MID MORNING...THEN REDEVELOP TONIGHT AS ISENTROPIC LIFT
INCREASES ACROSS THE TAF SITES. MAY SEE LIGHT RAIN DEVELOPING AT
KMHK BY LATE EVENING.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1050 PM EST TUE NOV 22 2011
.SYNOPSIS...
STRONG LOW PRESSURE, WILL MOVE NORTHEASTWARD THROUGH THE UPPER
OHIO VALLEY OVERNIGHT, WITH SHOWERS AND GUSTY WINDS INTO
WEDNESDAY. TEXAS HIGH PRESSURE WILL PROVIDE DRY AND SEASONABLE
CONDITIONS FOR THANKSGIVING DAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BASED ON BLEND OF RECENT SURFACE AND RADAR DATA PLUS HRRR AND NAM MODEL
OUTPUT, EXPECT SHOWERS TO DECREASE IN COVERAGE OVERNIGHT WEST OF
THE MOUNTAINS, AS THE NORTHEASTWARD MOVING LOW PRESSURE CENTER PASSES
THROUGH NORTHWEST PENNSYLVANIA LATE TONIGHT.
HAVE ADDED AREAS OF FOG NEAR THE MOUNTAINS, WITH DENSE FOG OVER
THE HIGHER ELEVATIONS PER RECENT SURFACE DATA, FOR EXAMPLE,
OAKLAND AIRPORT MD/K2G4/.
IN THE WAKE OF THE LOW PRESSURE PASSAGE, THERE CAN BE A DRY BREAK
FOLLOWED BY SCATTERED WRAP-AROUND SHOWERS WEDNESDAY. THE SHOWERS
CAN BE MORE NUMEROUS AT TIMES NEAR THE MOUNTAINS.
WILL MAINTAIN FLOOD WATCH UNTIL ITS EXPIRATION ABOUT MIDNIGHT AS RAIN
AMOUNTS SHOULD SUBSIDE BY THEN AND RUNOFF BEGINS TO SLACKEN. SO
FAR HAVE RECEIVED A COUPLE REPORTS OF ROAD FLOODING IN OHIO, WHERE
AN AREAL FLOOD WARNING HAS BEEN ISSUED. RECENT RADAR DATA HAS
SHOWN A NARROW BAND OF HEAVIER SHOWERS MOVING NORTHEASTWARD ALONG
THE WESTERN SLOPES OF THE LAUREL HIGHLANDS, WHERE A RECENT FLOOD
WARNING HAS BEEN ISSUED. FLOOD CAN CONTINUE THERE INTO EARLY
WEDNESDAY MORNING.
ALSO IN THE WAKE OF THIS PASSAGE, EXPECT WINDS TO GUST TO 25 MPH
LATE TONIGHT AND 30 TO 35 MPH DAYTIME WEDNESDAY.
USING BLEND OF HRRR AND NAM MODEL OUTPUT, FORECASTED TEMPERATURES
TO DROP NO MORE THAN A COUPLE DEGREES OVERNIGHT. TEMPERATURES
WEDNESDAY CAN ALSO BE STEADY OR SLOWLY FALLING SO MENTIONED
MORNING HIGHS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
PER RECENT SREF MODEL OUTPUT, HIGH PRESSURE COMING FROM TEXAS WILL
PROVIDE DRY CONDITIONS FOR THE THANKSGIVING HOLIDAY PERIOD.
FORECASTED DAYTIME HIGHS THURSDAY TO BE ABOUT 5 DEGREES WARMER
THAN NORMAL...AND ABOUT 10 DEGREES WARMER THAN NORMAL FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
BELOW NORMAL CONFIDENCE IN THE EXTENDED FORECAST...WITH VARYING
SOLUTIONS BETWEEN DETERMINISTIC AND ENSEMBLE MODELS.
THERE IS MODEL CONSENSUS THAT AN UPPER LEVEL TROUGH AND SURFACE
LOW WILL MOVE ACROSS THE CENTRAL U.S. ON SATURDAY. HOWEVER, MODELS
SHOW DIFFERENCES IN TIMING OF WHEN THE SURFACE FEATURE WILL MOVE
THROUGH THE OHIO VALLEY. THE 00Z GFS AND ITS ENSEMBLE SHOW SUNDAY
WHILE THE 00Z ECMWF AND CANADIAN ENSEMBLES SHOW MONDAY.
THERE ARE ALSO DIFFERING SOLUTIONS AS TO WHERE THE UPPER LEVEL
FEATURE WILL STOP AND PIVOT. GFS SHOWS MISSOURI WHILE ECMWF SHOWS
LAKE HURON WITH SECONDARY DEVELOPMENT OVER WEST VIRGINIA.
CONSIDERING THESE VARIANCES, CHOSE TO ADOPT HPC SOLUTION...WHICH
IS SOMEWHAT CLOSER TO THE 00Z ECMWF SOLUTION. 12Z ECMWF CAME IN
LOOKING MUCH CLOSER TO THE 00Z/12Z GFS SOLUTIONS...BUT WOULD LIKE
TO SEE SOME RUN-TO-RUN CONTINUITY BEFORE MAKING ADDITIONAL
FORECAST CHANGES.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
LARGE AREA OF VFR PUSHING INTO OHIO, EXTREME WESTERN PA AND
NORTHERN WV. ALLOWED SEVERAL HOURS OF THIS TO CONTINUE TONIGHT.
THE FRONT PASSES THROUGH 06-09Z, WINDS INCREASE, AND CIGS LOWER.
REMOVED CB FROM TERMINALS AS CHC OF TSTMS IS VERY LOW.
A BRIEF AREA OF WRAP AROUND SWINGS THROUGH WED AM AND AFTN WITH
LOWER CIGS, VSBY, AND RAIN. THEN SKIES BECOME SCT. WINDS STAY
GUSTY TO 30 KTS TIL LATE DAY.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
WITH HIGH PRESSURE ENTERING THE REGION FROM THE SOUTHWEST...EXPECT VFR
THROUGH SATURDAY NIGHT. A COLD FRONT APPROACHING FROM THE WEST
MAY BRING SHOWERS AND SOME RESTRICTIONS SUNDAY.
&&
.HYDROLOGY...
SINCE EARLY TUESDAY MORNING, BASIN AVERAGE RAINFALL HAS RANGED
BETWEEN 0.75 TO 1.00 INCHES OVER THE OHIO AND MONONGAHELA RIVER
BASINS. THE ALLEGHENY RIVER BASIN AVERAGED ABOUT 0.50 INCHES. THE
MUSKINGUM AND TUSCARAWAS RIVER BASINS AVERAGED ABOUT 1.00 INCH.
ADDITIONAL RAIN AMOUNTS OF UP 0.50 INCHES CAN OCCUR NEAR THE
MOUNTAINS OVERNIGHT.
HENCE, RIVER LEVELS ACROSS THE AREA WILL CONTINUE TO RISE SHARPLY
WITH CRESTING EXPECTED DAYTIME WEDNESDAY INTO EARLY THURSDAY. NO
FLOODING IS EXPECTED ALONG THE MAIN STEM RIVERS...ALTHOUGH SOME
SMALL TRIBUTARIES CAN GO OUT OF THEIR BANKS. SEE AREAL FLOOD
WARNINGS FOR UPDATES ON THIS SITUATION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR MDZ001.
OH...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR OHZ039>041-048>050-
057>059-068-069.
PA...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR PAZ020-021-029-031-
073>076.
WV...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR WVZ001>004-012-
021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1004 PM EST TUE NOV 22 2011
.SYNOPSIS...
STRONG LOW PRESSURE, WILL MOVE NORTHEASTWARD THROUGH THE UPPER
OHIO VALLEY OVERNIGHT, WITH SHOWERS AND GUSTY WINDS INTO
WEDNESDAY. TEXAS HIGH PRESSURE WILL PROVIDE DRY AND SEASONABLE
CONDITIONS FOR THANKSGIVING DAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BASED ON BLEND OF RECENT SURFACE AND RADAR DATA PLUS HRRR AND NAM MODEL
OUTPUT, EXPECT SHOWERS TO DECREASE IN COVERAGE OVERNIGHT WEST OF
THE MOUNTAINS, AS THE NORTHEASTWARD MOVING LOW PRESSURE CENTER PASSES
THROUGH NORTHWEST PENNSYLVANIA LATE TONIGHT. IN THE WAKE OF THIS
PASSAGE, THERE CAN BE A DRY BREAK FOLLOWED BY SCATTERED WRAP-
AROUND SHOWERS WEDNESDAY. THE SHOWERS CAN BE MORE NUMEROUS AT
TIMES NEAR THE MOUNTAINS.
WILL MAINTAIN FLOOD WATCH UNTIL ITS EXPIRATION ABOUT MIDNIGHT AS RAIN
AMOUNTS SHOULD SUBSIDE BY THEN AND RUNOFF BEGINS TO SLACKEN. SO
FAR HAVE RECEIVED A COUPLE REPORTS OF ROAD FLOODING IN OHIO, WHERE
AN AREAL FLOOD WARNING HAS BEEN ISSUED. RECENT RADAR DATA HAS
SHOWN A NARROW BAND OF HEAVIER SHOWERS MOVING NORTHEASTWARD ALONG
THE WESTERN SLOPES OF THE LAUREL HIGHLANDS, WHERE A RECENT FLOOD
WARNING HAS BEEN ISSUED. FLOOD CAN CONTINUE THERE INTO EARLY
WEDNESDAY MORNING.
ALSO IN THE WAKE OF THIS PASSAGE, EXPECT WINDS TO GUST TO 25 MPH
LATE TONIGHT AND 30 TO 35 MPH DAYTIME WEDNESDAY.
USING BLEND OF HRRR AND NAM MODEL OUTPUT, FORECASTED TEMPERATURES
TO DROP NO MORE THAN A COUPLE DEGREES OVERNIGHT. TEMPERATURES
WEDNESDAY CAN ALSO BE STEADY OR SLOWLY FALLING SO MENTIONED
MORNING HIGHS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
PER RECENT SREF MODEL OUTPUT, HIGH PRESSURE COMING FROM TEXAS WILL
PROVIDE DRY CONDITIONS FOR THE THANKSGIVING HOLIDAY PERIOD.
FORECASTED DAYTIME HIGHS THURSDAY TO BE ABOUT 5 DEGREES WARMER
THAN NORMAL...AND ABOUT 10 DEGREES WARMER THAN NORMAL FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
BELOW NORMAL CONFIDENCE IN THE EXTENDED FORECAST...WITH VARYING
SOLUTIONS BETWEEN DETERMINISTIC AND ENSEMBLE MODELS.
THERE IS MODEL CONSENSUS THAT AN UPPER LEVEL TROUGH AND SURFACE
LOW WILL MOVE ACROSS THE CENTRAL U.S. ON SATURDAY. HOWEVER, MODELS
SHOW DIFFERENCES IN TIMING OF WHEN THE SURFACE FEATURE WILL MOVE
THROUGH THE OHIO VALLEY. THE 00Z GFS AND ITS ENSEMBLE SHOW SUNDAY
WHILE THE 00Z ECMWF AND CANADIAN ENSEMBLES SHOW MONDAY.
THERE ARE ALSO DIFFERING SOLUTIONS AS TO WHERE THE UPPER LEVEL
FEATURE WILL STOP AND PIVOT. GFS SHOWS MISSOURI WHILE ECMWF SHOWS
LAKE HURON WITH SECONDARY DEVELOPMENT OVER WEST VIRGINIA.
CONSIDERING THESE VARIANCES, CHOSE TO ADOPT HPC SOLUTION...WHICH
IS SOMEWHAT CLOSER TO THE 00Z ECMWF SOLUTION. 12Z ECMWF CAME IN
LOOKING MUCH CLOSER TO THE 00Z/12Z GFS SOLUTIONS...BUT WOULD LIKE
TO SEE SOME RUN-TO-RUN CONTINUITY BEFORE MAKING ADDITIONAL
FORECAST CHANGES.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
LARGE AREA OF VFR PUSHING INTO OHIO, EXTREME WESTERN PA AND
NORTHERN WV. ALLOWED SEVERAL HOURS OF THIS TO CONTINUE TONIGHT.
THE FRONT PASSES THROUGH 06-09Z, WINDS INCREASE, AND CIGS LOWER.
REMOVED CB FROM TERMINALS AS CHC OF TSTMS IS VERY LOW.
A BRIEF AREA OF WRAP AROUND SWINGS THROUGH WED AM AND AFTN WITH
LOWER CIGS, VSBY, AND RAIN. THEN SKIES BECOME SCT. WINDS STAY
GUSTY TO 30 KTS TIL LATE DAY.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
WITH HIGH PRESSURE ENTERING THE REGION FROM THE SOUTHWEST...EXPECT VFR
THROUGH SATURDAY NIGHT. A COLD FRONT APPROACHING FROM THE WEST
MAY BRING SHOWERS AND SOME RESTRICTIONS SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR MDZ001.
OH...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR OHZ039>041-048>050-
057>059-068-069.
PA...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR PAZ020-021-029-031-
073>076.
WV...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR WVZ001>004-012-
021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
735 PM EST TUE NOV 22 2011
.SYNOPSIS...
STRONG LOW PRESSURE, WILL MOVE NORTHEASTWARD THROUGH THE UPPER
OHIO VALLEY OVERNIGHT, WITH SHOWERS AND GUSTY WINDS INTO
WEDNESDAY. TEXAS HIGH PRESSURE WILL PROVIDE DRY AND SEASONABLE
CONDITIONS FOR THANKSGIVING DAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BASED ON BLEND OF RECENT SURFACE AND RADAR DATA PLUS HRRR, NAM,
AND GFS MODEL OUTPUT, EXPECT SHOWERS TO SLIGHTLY DECREASE IN
COVERAGE OVERNIGHT AS THE NORTHEASTWARD MOVING LOW PRESSURE CENTER
PASSES THROUGH NORTHWEST PENNSYLVANIA LATE TONIGHT. IN THE WAKE
OF THIS PASSAGE, THERE CAN BE A DRY BREAK FOLLOWED BY SCATTERED
WRAP- AROUND SHOWERS WEDNESDAY. THE SHOWERS CAN BE MORE NUMEROUS
AT TIMES NEAR THE MOUNTAINS.
WILL MAINTAIN FLOOD WATCH UNTIL RAIN AMOUNTS SUBSIDE. SO FAR HAVE
RECEIVED A COUPLE REPORTS OF ROAD FLOODING IN OHIO, WHERE AN AREAL FLOOD
WARNING HAS BEEN ISSUED.
ALSO IN THE WAKE OF THIS PASSAGE, EXPECT WINDS TO GUST TO 25 MPH
LATE TONIGHT AND 30 TO 35 MPH DAYTIME WEDNESDAY.
USING BLEND OF HRRR AND NAM MODEL OUTPUT, FORECASTED TEMPERATURES
TO DROP NO MORE THAN A COUPLE DEGREES OVERNIGHT. TEMPERATURES
WEDNESDAY CAN ALSO BE STEADY OR SLOWLY FALLING SO MENTIONED
MORNING HIGHS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
PER RECENT SREF MODEL OUTPUT, HIGH PRESSURE COMING FROM TEXAS WILL
PROVIDE DRY CONDITIONS FOR THE THANKSGIVING HOLIDAY PERIOD.
FORECASTED DAYTIME HIGHS THURSDAY TO BE ABOUT 5 DEGREES WARMER
THAN NORMAL...AND ABOUT 10 DEGREES WARMER THAN NORMAL FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
BELOW NORMAL CONFIDENCE IN THE EXTENDED FORECAST...WITH VARYING
SOLUTIONS BETWEEN DETERMINISTIC AND ENSEMBLE MODELS.
THERE IS MODEL CONSENSUS THAT AN UPPER LEVEL TROUGH AND SURFACE
LOW WILL MOVE ACROSS THE CENTRAL U.S. ON SATURDAY. HOWEVER, MODELS
SHOW DIFFERENCES IN TIMING OF WHEN THE SURFACE FEATURE WILL MOVE
THROUGH THE OHIO VALLEY. THE 00Z GFS AND ITS ENSEMBLE SHOW SUNDAY
WHILE THE 00Z ECMWF AND CANADIAN ENSEMBLES SHOW MONDAY.
THERE ARE ALSO DIFFERING SOLUTIONS AS TO WHERE THE UPPER LEVEL
FEATURE WILL STOP AND PIVOT. GFS SHOWS MISSOURI WHILE ECMWF SHOWS
LAKE HURON WITH SECONDARY DEVELOPMENT OVER WEST VIRGINIA.
CONSIDERING THESE VARIANCES, CHOSE TO ADOPT HPC SOLUTION...WHICH
IS SOMEWHAT CLOSER TO THE 00Z ECMWF SOLUTION. 12Z ECMWF CAME IN
LOOKING MUCH CLOSER TO THE 00Z/12Z GFS SOLUTIONS...BUT WOULD LIKE
TO SEE SOME RUN-TO-RUN CONTINUITY BEFORE MAKING ADDITIONAL
FORECAST CHANGES.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
LARGE AREA OF VFR PUSHING INTO OHIO, EXTREME WESTERN PA AND
NORTHERN WV. ALLOWED SEVERAL HOURS OF THIS TO CONTINUE TONIGHT.
THE FRONT PASSES THROUGH 06-09Z, WINDS INCREASE, AND CIGS LOWER.
REMOVED CB FROM TERMINALS AS CHC OF TSTMS IS VERY LOW.
A BRIEF AREA OF WRAP AROUND SWINGS THROUGH WED AM AND AFTN WITH
LOWER CIGS, VSBY, AND RAIN. THEN SKIES BECOME SCT. WINDS STAY
GUSTY TO 30 KTS TIL LATE DAY.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
WITH HIGH PRESSURE ENTERING THE REGION FROM THE SOUTHWEST...EXPECT VFR
THROUGH SATURDAY NIGHT. A COLD FRONT APPROACHING FROM THE WEST
MAY BRING SHOWERS AND SOME RESTRICTIONS SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR MDZ001.
OH...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR OHZ039>041-048>050-
057>059-068-069.
PA...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR PAZ020-021-029-031-
073>076.
WV...FLOOD WATCH UNTIL MIDNIGHT EST TONIGHT FOR WVZ001>004-012-
021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
213 PM CST MON NOV 21 2011
.DISCUSSION...
LOW CLOUDS/FOG WILL BE THE MAIN CHALLENGE TONIGHT AND TUESDAY. LOW
LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH INVERSION ACROSS THE
MIDWEST. CLOUDS HAD THINNED MOMENTARILY OVER PORTIONS OF EAST
CENTRAL MN AND WESTERN WISCONSIN DURING THE AFTERNOON.
HOWEVER...ANOTHER BATCH OF LOW CLOUDS WAS ADVANCING NORTHWARD OUT OF
IOWA. NAM40 RH PROGS SEEMS TO HAVE A GOOD HANDLE ON IT WITH CLOUDS
BECOMING MORE EXTENSIVE AGAIN OVER MUCH OF OUR EASTERN TWO THIRDS OF
OUR FORECAST AREA. SOUTHERLY AIRFLOW SHOULD BE ENOUGH TO KEEP SKIES
OVER WESTERN ONE THIRD MOSTLY CLEAR OVERNIGHT. LITTLE DIURNAL TEMP
CHANGE OVERNIGHT EXCEPT IN THE WEST AND IN SNOW COVER AREAS OF
CENTRAL MN...TEMPERATURES SHOULD DROP OFF IN THE TEENS.
MAX TEMPS ON TUESDAY WILL BE SLIGHTLY WARMER WITH HIGHS IN THE UPPER
30S TO LOWER 40S.
MODERATE TO STRONG WARM AIR ADVECTION WILL CONTINUE THROUGH THE END
OF THE WORK WEEK. LOW CLOUDS SHOULD FINALLY LIFT NORTHEAST AND
DISSIPATE ACROSS MUCH OF THE OUR BY WEDNESDAY. TEMPERATURES WILL
MODERATE INTO THE UPPER 40S TO MIDDLE 50S BY THANKSGIVING DAY.
MODELS HAVE BEEN CONSISTENT IN BRING SEVERAL SHORTWAVE TROUGHS FROM
THE PACIFIC INTO THE SOUTHWEST U.S. THESE WAVES WILL LIFT NORTHEAST
OVER THE MIDWEST OVER THE NEXT SEVERAL DAYS. NEXT CHANCE OF PRECIP
WILL OCCUR FRIDAY EVENING AND SATURDAY OVER OVER THE SOUTHEAST HALF
OF OUR FORECAST AREA.
THE EXTENDED OUTLOOK HAS A STRONG LOW PRESSURE SYSTEM TO LIFT
NORTHEAST OVER THE GREAT LAKES BY MONDAY OF NEXT WEEK. THIS SYSTEM
WILL DRAWN SOME COLDER AIR INTO THE NORTHERN PLAINS AND EVENTUALLY
ACROSS THE UPPER MIDWEST TUESDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
POORLY HANDLED STRATUS CONTINUES TO PLAGUE THE AREA THIS MORNING.
HAVE A PATCH OF IFR STRATUS THAT IS SLOWLY MOVING NORTH ACROSS ERN
MN AND WRN WI...THEN A PATCH OF VFR CIGS...FOLLOWED BY ANOTHER
BATCH OF MVFR STRATUS SE OF THAT. RUC H95 RH FIELD SHOWS IFR CIGS
SLOWLY DRIFTING NORTH THROUGH THE AFTERNOON. LVN ALREADY VFR...AND
PIREPS FROM SOUTH OF MSP INDICATING CIGS ARE SCT-BKN...SO DO THINK
A SCATTERING OUT IS IMMINENT AT MSP...FOLLOWED SHORTLY BY RNH.
TRIED TIMING NEXT ROUND OF MVFR CIGS NW UP INTO THE AREA...BUT ITS
NOT MOVING VERY FAST AT THE MOMENT...SO MAY BE LATER FOR A
RETURN TO RESTRICTED CIGS AT RNH/MSP THAN CURRENTLY INDICATED.
WHATEVER HAPPENS...CONFIDENCE HIGH GIVEN MODEL AGREEMENT IN
IFR/MVFR STRATUS SPREADING BACK ACROSS THE AREA TONIGHT...AS WEAK
LOW LEVEL FLOW NEVER REALLY CLEANS THINGS OUT THIS AFTERNOON...NOT
TO MENTION THE FACT THAT THE LIGHT S/SE WINDS IN PLACE WILL ONLY
HELP ADVECT THE BANK OF STRATUS FROM IA INTO CENTRAL WI BACK
ACROSS THE TERMINALS. ONLY FIELDS THAT MAY MISS OUT ON THE LOWER
CIGS WILL BE RWF/AXN ONCE AGAIN...BUT IT WILL BE VERY
CLOSE...HENCE THE SCT LOWER CLOUD LAYERS THERE. ANY IMPROVEMENT
WILL BE SLOW TO COME BY ON TUESDAY AS A SFC RIDGE AND ATTENDANT
LIGHT FLOW WILL BE OVER THE AREA. TEND TO AGREE WITH THE NAM THAT
ENOUGH OF A DRY SW PUSH WILL NOT ENTER THE MPX AREA UNTIL AFTER
18Z...WHEN ANY SIGNIFICANT CIG IMPROVEMENTS WILL LIKELY WAIT
UNTIL.
KMSP...LOW CONFIDENCE FORECAST THIS TAF PERIOD AS NO PIECE OF
GUIDANCE IS REALLY HANDLING THINGS ALL THAT WELL. IN GENERAL LIKE
THE IDEA OF THE GFSLAMP OF VFR CIGS COMING BACK FOR A BIT THIS
AFTERNOON...FOLLOWED BY A RETURN TO IFR CIGS TONIGHT. THIS MAKES
SENSE GIVEN CURRENT STRATUS/CLEAR SLOT/STRATUS CLOUD PATTERN. WITH
SFC RIDGE OVERHEAD...WILL SEE RATHER VARIABLE WINDS TONIGHT
THROUGH MOST OF TUESDAY...BUT BY THE END OF THE DAY...THE FIELD
SHOULD START TO SEE A MORE SW WIND BECOME ESTABLISHED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JM/MG
AREA FORECAST DISCUSSION
NWS DULUTH MN
1221 PM CST MON NOV 21 2011
.AVIATION.../12Z TAF ISSUANCE/
LATEST REGIONAL OBSERVATIONS SATELLITE IMAGERY SHOWS A LARGE AREA
OF LOW CLOUD ACROSS THE NORTHLAND CURRENTLY. THIS CLOUD COVER HAS
INCREASE IN COVERAGE ACROSS OUR MN ZONES THIS MORNING...WITH SOME
DECREASE IN COVERAGE ACROSS OUR WI ZONES. HOWEVER OVERALL THINK
THAT THE LOW CLOUDS SHOULD STAY FAIRLY WIDESPREAD ACROSS OUR CWA
THROUGH THE TAF PERIOD DUE TO LIMITED MIXING AND DRY AIR ADVECTION
EXPECTED. CIGS WILL GENERALLY BE IN THE IFR/LOW MVFR RANGE...AND
THERE WILL BE AREAS OF FOG WITH IFR/MVFR VSBYS AS WELL.
&&
.PREV DISCUSSION... /ISSUED 1015 AM CST MON NOV 21 2011/
UPDATE...EXTENSIVE STRATUS DECK COVERING A LARGE PART OF CWA.
COLD MOIST LAYER NEAR SFC IS BEING TOPPED BY A LAYER OF WARM AIR
ADVECTION PRODUCED BY DEPARTING SFC HIGH. SMALL AREA OF CLEARING
OCCURRING OVER ERN BAYFIELD TO ASHLAND/IRON COUNTIES AS INITIAL
HOLE IN DECK ALLOWED FOR AN AREA OF INCREASED MIXING WITHIN
RELATIVELY SHALLOW MOIST LAYER. FCST RUC13 SNDGS SHOW DEVELOPING
SUBSIDENCE INVERSION PROFILE SO SUSPECT THAT IT MAY BE TOUGH TO
CLEAR CLOUDS FROM MANY LOCATIONS TODAY. LOWERED TEMPS/INCREASED SKY
GRIDS/ADDED FOG TO ZFP/GRIDS.
PREV DISCUSSION... /ISSUED 553 AM CST MON NOV 21 2011/
AVIATION...11/21/12Z ISSUANCE...
SURFACE RIDGING OVER SNOW COVER AND A FAST AND DEEP FLOW OF WARM
DRY AIR OF PACIFIC ORIGIN IS RAPIDLY STABILIZING THE COLUMN. SO...
WARM AIR IS TRAPPING A SHALLOW LAYER OF INCREASINGLY MOIST AIR
NEAR THE SURFACE. AREAS OF IFR IN LOW STRATUS OVER NORTHWEST
WISCONSIN...THE DULUTH AREA NORTHWARD THROUGH THE ARROWHEAD WILL
ONLY SLOWLY BECOME VFR SCATTERED OR CLEAR THIS MORNING. THERE IS A
THREAT OF IFR CONDITIONS IN STRATUS AGAIN DEVELOPING THIS EVENING.
PREV DISCUSSION... /ISSUED 324 AM CST MON NOV 21 2011/
SHORT TERM...
CURRENT SAT SUBTRACTION CURVE IMAGERY AND SFC OBS SHOWING
GRADUALLY EXPANDING AREA OF LOW CLOUDS OVER THE EASTERN HALF OF
THE FORECAST AREA. TEMPERATURES AT 300 AM WERE GENERALLY IN THE
TEENS TO LOW 20S UNDER THE CLOUD COVER. MOSTLY CLEAR SKIES OVER
THE WESTERN ZONES ALLOWED EARLY MORNING TEMPS TO DROP INTO THE
SINGLE DIGITS. A FEW LOCATIONS IN THE IRON RANGE REGION SAW SUB
ZERO TEMPS BRIEFLY BEFORE A DECK HIGH CLOUDS ARRIVED AND TEMPS
REBOUNDED.
THE REGION WILL BE POSITIONED ON THE BACK SIDE OF EXITING HIGH
PRESSURE AS A SPLIT ZONAL FLOW ALLOWS FOR TWO SHORT WAVES TO TRACK
TO THE NORTH AND SOUTH OF THE WESTERN GREAT LAKES THROUGH TUESDAY.
A PERSISTENT SW 25-30 LLJ WILL RESULT IN INCREASING MOISTURE AND
RISING H85 TEMPS TODAY AND TONIGHT. LATEST NAM BUFR SOUNDINGS AT
KELO/KHIB/KDLH SUGGEST PROFILES BECOME SATURATED TO 900 MB BY LATE
THIS EVENING. THE LOW LEVEL MOISTURE AND FORCING FROM WAA
COMBINED WITH CLOUD TOP TEMPS AROUND NEGATIVE 5 C WOULD SUPPORT
PATCHY DZ/FZDZ. TO ACCOUNT FOR THIS...INCREASED CLOUD COVER
OVERNIGHT AND INTRODUCED PATCHY FOG TO MN ARROWHEAD REGION AT THIS
TIME.
OUTLOOK...TUESDAY NIGHT THROUGH MONDAY...
NORTH-SOUTH SURFACE RIDGING OVER OUR AREA...WITH A VERY WEAK SURFACE
GRADIENT IS ACCOMPANIED BY SIGNIFICANT WARMING ALOFT AND A CONTINUED
DEEP ZONAL FLOW OF WARM AND VERY DRY AIR OF PACIFIC ORIGIN. THE
WARM ADVECTION AND HEIGHT GRADIENT INCREASES AT ALL LEVELS...AND SO
DOES THE STABILITY AND TENDENCY OF WINDS TO INCREASE AND VEER WITH
HEIGHT...THURSDAY AND THURSDAY NIGHT. THE GFS SEEMS TO OVERDO A
WEAK AND SHALLOW COLD FRONT WHERE THE EUROPEAN SUGGESTS A SHALLOW
REPLENISHMENT OF VERY SHALLOW RELATIVELY COLD AIR AT THE SURFACE AND
CONTINUED RIDGING AND WARMTH ALOFT FRIDAY AND FRIDAY NIGHT. AS A
RESULT...WE REMAIN AWARE OF A POSSIBILITY OF LOW CLOUDS AND CHILLIER
THAN EXPECTED WEATHER TUESDAY NIGHT THROUGH FRIDAY...ESPECIALLY NEAR
THE BIG LAKE. ANOTHER COLD FRONT BRINGS A CHANCE OF PRECIPITATION
AND DEEPER COLD AIR LATE FRIDAY NIGHT AND SATURDAY. EVEN WITH THE
FRONT...TEMPERATURES REMAIN WELL ABOVE SEASONABLE NORMALS SATURDAY
WITH ANOTHER DRY WARM-UP BEGINNING SUNDAY AND CONTINUING MONDAY.
ALL THE MODELS HAVE ANOTHER COLD FRONT APPROACHING LATE MONDAY...
THE EUROPEAN SUGGESTS THAT THIS MAY BE THE BEGINNING OF A PATTERN
CHANGE WHILE THE GFS TENDS TO KEEP OUR AREA IN DRY WARM PACIFIC AIR.
&&
.POINT TEMPS/POPS...
DLH 28 23 37 24 / 10 10 10 10
INL 25 13 36 21 / 10 10 10 10
BRD 29 16 36 22 / 0 10 0 0
HYR 33 22 37 22 / 10 10 0 10
ASX 33 24 37 26 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...BERDES
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1154 AM CST MON NOV 21 2011
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
ISSUE FOR TODAY IS MESSY CLOUD FORECAST. THAT AND SNOW COVER WILL BE
PROBLEMATIC FOR TEMPERATURES TODAY. CURRENT SURFACE RIDGE OF HIGH
PRESSURE EXTENDS EAST ACROSS WI INTO CENTRAL MN. TEMPERATURES ACROSS
CENTRAL MN OVER FRESH SNOWPACK DROPPED INTO THE SINGLE DIGITS...BUT
HAVE RECOVERED SOME IN THE WEST AS WINDS HAVE COME UP A BIT.
EXPANDING AREA OF STRATUS IN SHALLOW SELY FLOW UNDER INVERSION HAS
BEEN STEADILY PUSHING NE ACROSS SE/EC MN OVERNITE. WITH LOW LEVEL
WINDS HAVING AN EASTERLY COMPONENT TODAY...CLOUDS MAY BE DIFFICULT
TO REMOVE. LOWERED MAX TEMP FOR THIS AFTERNOON SEVERAL DEGREES WC
WI INTO ADJOINING AREAS OF MN.
ELY FLOW TONIGHT WILL BRING RISK OF STRATUS IN E MN INTO WI. 06Z
NAM 925 MB RH TRIES TO PICK UP ON THIS. TRENDED CLOUD COVER UPWARD
SOME FOR TONIGHT...BUT WILL LET NEXT SHIFT MAKE FURTHER ADJUSTMENTS
WHEN WE SEE HOW CLOUDS BEHAVE TODAY.
PRECIP FROM SYSTEM TRACKING ACROSS MO INTO OHIO VALLEY ON TUESDAY
WILL STAY SE OF AREA...BUT PROBABLY ENUF CLOUD COVER TO KEEP TEMPS
DOWN A FEW DEGREES.
WARM UP GETS INTO FULL GEAR WEDNESDAY AS WE GET INTO BROAD SWLY FLOW
AHEAD OF FRIDAY`S COLD FRONT. TEMPS PROBABLY WILL GET DAMPED A BIT
FROM REMAINING SNOW COVER ACROSS N PORTIONS OF CWA. SOME RISK OF
LOWER CLOUDS THURSDAY ACROSS N AREAS AS DEWPOINTS BEGIN TO RISE INTO
MID 30S.
DIDN`T MAKE SIGNIFICANT CHANGES IN PRECIP FORECAST FOR FRI/SAT. GFS
HAS CONSIDERABLY HIGHER QPF THAN ECMWF (STILL ONLY .10 TO .20) WITH
MAIN AREA ACROSS SE MN INTO WI. ANY PCPN WOULD BEGIN AS RAIN WITH A
CHANGE TO SNOW AS COLD FRONT MOVES THRU AREA. 00Z GEM IS SIMILAR TO
THE GFS SOLUTION. COOLING LOOKS RATHER BRIEF WITH UPPER RIDGE
REBUILDING EARLY NEXT WEEK.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
.AVIATION.../18Z TAF ISSUANCE/
POORLY HANDLED STRATUS CONTINUES TO PLAGUE THE AREA THIS MORNING.
HAVE A PATCH OF IFR STRATUS THAT IS SLOWLY MOVING NORTH ACROSS ERN
MN AND WRN WI...THEN A PATCH OF VFR CIGS...FOLLOWED BY ANOTHER
BATCH OF MVFR STRATUS SE OF THAT. RUC H95 RH FIELD SHOWS IFR CIGS
SLOWLY DRIFTING NORTH THROUGH THE AFTERNOON. LVN ALREADY VFR...AND
PIREPS FROM SOUTH OF MSP INDICATING CIGS ARE SCT-BKN...SO DO THINK
A SCATTERING OUT IS IMMINENT AT MSP...FOLLOWED SHORTLY BY RNH.
TRIED TIMING NEXT ROUND OF MVFR CIGS NW UP INTO THE AREA...BUT ITS
NOT MOVING VERY FAST AT THE MOMENT...SO MAY BE LATER FOR A
RETURN TO RESTRICTED CIGS AT RNH/MSP THAN CURRENTLY INDICATED.
WHATEVER HAPPENS...CONFIDENCE HIGH GIVEN MODEL AGREEMENT IN
IFR/MVFR STRATUS SPREADING BACK ACROSS THE AREA TONIGHT...AS WEAK
LOW LEVEL FLOW NEVER REALLY CLEANS THINGS OUT THIS AFTERNOON...NOT
TO MENTION THE FACT THAT THE LIGHT S/SE WINDS IN PLACE WILL ONLY
HELP ADVECT THE BANK OF STRATUS FROM IA INTO CENTRAL WI BACK
ACROSS THE TERMINALS. ONLY FIELDS THAT MAY MISS OUT ON THE LOWER
CIGS WILL BE RWF/AXN ONCE AGAIN...BUT IT WILL BE VERY
CLOSE...HENCE THE SCT LOWER CLOUD LAYERS THERE. ANY IMPROVEMENT
WILL BE SLOW TO COME BY ON TUESDAY AS A SFC RIDGE AND ATTENDANT
LIGHT FLOW WILL BE OVER THE AREA. TEND TO AGREE WITH THE NAM THAT
ENOUGH OF A DRY SW PUSH WILL NOT ENTER THE MPX AREA UNTIL AFTER
18Z...WHEN ANY SIGNIFICANT CIG IMPROVEMENTS WILL LIKELY WAIT
UNTIL.
KMSP...LOW CONFIDENCE FORECAST THIS TAF PERIOD AS NO PIECE OF
GUIDANCE IS REALLY HANDLING THINGS ALL THAT WELL. IN GENERAL LIKE
THE IDEA OF THE GFSLAMP OF VFR CIGS COMING BACK FOR A BIT THIS
AFTERNOON...FOLLOWED BY A RETURN TO IFR CIGS TONIGHT. THIS MAKES
SENSE GIVEN CURRENT STRATUS/CLEAR SLOT/STRATUS CLOUD PATTERN. WITH
SFC RIDGE OVERHEAD...WILL SEE RATHER VARIABLE WINDS TONIGHT
THROUGH MOST OF TUESDAY...BUT BY THE END OF THE DAY...THE FIELD
SHOULD START TO SEE A MORE SW WIND BECOME ESTABLISHED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1015 AM CST MON NOV 21 2011
.UPDATE...EXTENSIVE STRATUS DECK COVERING A LARGE PART OF CWA.
COLD MOIST LAYER NEAR SFC IS BEING TOPPED BY A LAYER OF WARM AIR
ADVECTION PRODUCED BY DEPARTING SFC HIGH. SMALL AREA OF CLEARING
OCCURRING OVER ERN BAYFIELD TO ASHLAND/IRON COUNTIES AS INITIAL
HOLE IN DECK ALLOWED FOR AN AREA OF INCREASED MIXING WITHIN
RELATIVELY SHALLOW MOIST LAYER. FCST RUC13 SNDGS SHOW DEVELOPING
SUBSIDENCE INVERSION PROFILE SO SUSPECT THAT IT MAY BE TOUGH TO
CLEAR CLOUDS FROM MANY LOCATIONS TODAY. LOWERED TEMPS/INCREASED SKY
GRIDS/ADDED FOG TO ZFP/GRIDS.
&&
.PREV DISCUSSION... /ISSUED 553 AM CST MON NOV 21 2011/
AVIATION...11/21/12Z ISSUANCE...
SURFACE RIDGING OVER SNOW COVER AND A FAST AND DEEP FLOW OF WARM
DRY AIR OF PACIFIC ORIGIN IS RAPIDLY STABILIZING THE COLUMN. SO...
WARM AIR IS TRAPPING A SHALLOW LAYER OF INCREASINGLY MOIST AIR
NEAR THE SURFACE. AREAS OF IFR IN LOW STRATUS OVER NORTHWEST
WISCONSIN...THE DULUTH AREA NORTHWARD THROUGH THE ARROWHEAD WILL
ONLY SLOWLY BECOME VFR SCATTERED OR CLEAR THIS MORNING. THERE IS A
THREAT OF IFR CONDITIONS IN STRATUS AGAIN DEVELOPING THIS EVENING.
PREV DISCUSSION... /ISSUED 324 AM CST MON NOV 21 2011/
SHORT TERM...
CURRENT SAT SUBTRACTION CURVE IMAGERY AND SFC OBS SHOWING
GRADUALLY EXPANDING AREA OF LOW CLOUDS OVER THE EASTERN HALF OF
THE FORECAST AREA. TEMPERATURES AT 300 AM WERE GENERALLY IN THE
TEENS TO LOW 20S UNDER THE CLOUD COVER. MOSTLY CLEAR SKIES OVER
THE WESTERN ZONES ALLOWED EARLY MORNING TEMPS TO DROP INTO THE
SINGLE DIGITS. A FEW LOCATIONS IN THE IRON RANGE REGION SAW SUB
ZERO TEMPS BRIEFLY BEFORE A DECK HIGH CLOUDS ARRIVED AND TEMPS
REBOUNDED.
THE REGION WILL BE POSITIONED ON THE BACK SIDE OF EXITING HIGH
PRESSURE AS A SPLIT ZONAL FLOW ALLOWS FOR TWO SHORT WAVES TO TRACK
TO THE NORTH AND SOUTH OF THE WESTERN GREAT LAKES THROUGH TUESDAY.
A PERSISTENT SW 25-30 LLJ WILL RESULT IN INCREASING MOISTURE AND
RISING H85 TEMPS TODAY AND TONIGHT. LATEST NAM BUFR SOUNDINGS AT
KELO/KHIB/KDLH SUGGEST PROFILES BECOME SATURATED TO 900 MB BY LATE
THIS EVENING. THE LOW LEVEL MOISTURE AND FORCING FROM WAA
COMBINED WITH CLOUD TOP TEMPS AROUND NEGATIVE 5 C WOULD SUPPORT
PATCHY DZ/FZDZ. TO ACCOUNT FOR THIS...INCREASED CLOUD COVER
OVERNIGHT AND INTRODUCED PATCHY FOG TO MN ARROWHEAD REGION AT THIS
TIME.
OUTLOOK...TUESDAY NIGHT THROUGH MONDAY...
NORTH-SOUTH SURFACE RIDGING OVER OUR AREA...WITH A VERY WEAK SURFACE
GRADIENT IS ACCOMPANIED BY SIGNIFICANT WARMING ALOFT AND A CONTINUED
DEEP ZONAL FLOW OF WARM AND VERY DRY AIR OF PACIFIC ORIGIN. THE
WARM ADVECTION AND HEIGHT GRADIENT INCREASES AT ALL LEVELS...AND SO
DOES THE STABILITY AND TENDENCY OF WINDS TO INCREASE AND VEER WITH
HEIGHT...THURSDAY AND THURSDAY NIGHT. THE GFS SEEMS TO OVERDO A
WEAK AND SHALLOW COLD FRONT WHERE THE EUROPEAN SUGGESTS A SHALLOW
REPLENISHMENT OF VERY SHALLOW RELATIVELY COLD AIR AT THE SURFACE AND
CONTINUED RIDGING AND WARMTH ALOFT FRIDAY AND FRIDAY NIGHT. AS A
RESULT...WE REMAIN AWARE OF A POSSIBILITY OF LOW CLOUDS AND CHILLIER
THAN EXPECTED WEATHER TUESDAY NIGHT THROUGH FRIDAY...ESPECIALLY NEAR
THE BIG LAKE. ANOTHER COLD FRONT BRINGS A CHANCE OF PRECIPITATION
AND DEEPER COLD AIR LATE FRIDAY NIGHT AND SATURDAY. EVEN WITH THE
FRONT...TEMPERATURES REMAIN WELL ABOVE SEASONABLE NORMALS SATURDAY
WITH ANOTHER DRY WARM-UP BEGINNING SUNDAY AND CONTINUING MONDAY.
ALL THE MODELS HAVE ANOTHER COLD FRONT APPROACHING LATE MONDAY...
THE EUROPEAN SUGGESTS THAT THIS MAY BE THE BEGINNING OF A PATTERN
CHANGE WHILE THE GFS TENDS TO KEEP OUR AREA IN DRY WARM PACIFIC AIR.
&&
.POINT TEMPS/POPS...
DLH 28 23 37 24 / 10 10 10 0
INL 25 13 36 22 / 10 10 10 0
BRD 29 16 36 23 / 0 10 0 0
HYR 33 22 37 21 / 10 10 0 0
ASX 33 24 37 25 / 10 10 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...CANNON
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
955 PM CST TUE NOV 22 2011
.DISCUSSION...
Will hold off on any dense fog advisory for western sections of the
forecast area for later tonight. As anticipated the western edge of
stratus deck has slowed its eastward progression across eastern KS
since 01z. Short range models have not done a particularly good job
handling these low clouds. Surface ridge axis closely mirrors cloud
edge and is expected to shift east into far western MO after
midnight. Latest NAM Bufr soundings no longer clear out the stratus
at MCI. If this were to occur, and it is a distinct possibility,
then those clouds will inhibit dense fog formation. Also have to
consider the probability of dense fog forming along/west of the
stratus deck which could then blend in with the stratus and in
effect further stall the eastward clearing. Too much uncertainty on
timing and not enough confidence that dense fog duration would be
long enough to issue an advisory at this time. Best to monitor for
now.
MJ
&&
.PREV DISCUSSION...
/247 PM CST Tue Nov 22 2011/
Concerns in the short term primarily deal with fog potential
overnight as well as temperatures on Thanksgiving.
Stratus behind a departing upper level shortwave continues to linger
across much of the region this afternoon; trapped under a low-level
shortwave ridge. There have been slight indications that drier low
level air is beginning to mix southeast however removing all the
stratus before sunset looks doubtful. The low-level ridge axis will
gradually slide southeast this evening, which may allow the western
zones to partially clear towards midnight and shift stratus eastward.
Given ample low level moisture, subsidence aloft, and very light
surface winds the development of radiation fog seems likely. Further
east, expecting stratus to linger much longer through the night, with
additional MVFR fog developing. Any breaks in the stratus would allow
for periods of dense fog to occur.
Wednesday: Mid-level heights will steadily build through the middle
portions of the week with surface high pressure moving southeast of
the CWA during the day on Wednesday. Morning fog will take a few
hours to mix out but strong warm air advection and a light south
wind should promote a climb into the 50s in most locations.
Thanksgiving: Weather conditions for Thanksgiving should end up being
almost spectacular. As upper level troughing moves into the Southwest
United States lee side troughing will begin to develop amplifying the
surface pressure gradient over Kansas and Missouri. Soundings suggest
we`ll mix up to around 900 mb by mid-afternoon, which should result
in middle to perhaps even upper 60s in most locations. There will be
a bit of concern for upper level cirrus especially with a deepening
southwest flow pattern aloft. Believe it or not, this could fall as
one of the warmest Thanksgiving holidays on record. The warmest
Thanksgivings ever recorded fell on 11/26/98, 11/24/1966, and
11/25/1926 all at 70 degrees.
Dux
Friday - Tuesday:
Models have shown good continuity bringing a front through Friday
evening/Friday night and there is only minor differences, for a four
day forecast, in timing. Strong warm and moist advection ahead of
the front combined with strong large scale forcing ahead of stout
trough should result in widespread rainfall across the area Friday
night. Confidence is high that it will rain throughout the region so
have bumped POPs up across the forecast area for this time frame.
Instability and lapse rates look fairly weak so have scaled back
thunder mention, especially during the Friday afternoon time frame
when the trough is still very removed from the region. Have
maintained thunder mention for the overnight period as forcing from
the trough combined with marginal lapse rates should produce some
thunder across the forecast area. Still think given the lack of/weak
instability that storms should be isolated in nature and not nearly
as widespread as the shower/rain activity.
Uncertainty really increases for the latter half of the weekend.
Ensembles from the GEFS to the ECMWF and the NAEFS have such a high
degree of variability with the upper level height fields it yields
minimal confidence that any one operational model is more correct
over anything else. If a trend can be determined it is that at some
point Sunday into Tuesday a trough or closed low will develop
somewhere over the eastern half of the CONUS. The intensity, timing
and location are all suspect at this point and as a result did not
deviate from the forecast initialization which keeps the region
relatively cool and dry for now. It also seems that this
troughing/closed low over the east may phase with a northern stream
system moving out of southern Canada that adds strength to the
trough/low giving it more longevity. This occurs as a ridge over the
western CONUS and eastern Pacific strengthens possibly setting up a
blocking pattern over North America.
CDB
&&
.AVIATION...
For the 00z TAFs, current thinking is mvfr stratus will be slower to
clear. While back edge of the stratus deck/clearing line
extrapolates to reach all 3 terminals by 05z-06z expect to see
fog/ifr stratus form across eastern KS where clouds clear, thus
delaying the clearing at the terminals. With surface winds becoming
nearly calm as the surface ridge edges east plus the moisture left
by last nights rains fog formation is becoming increasingly likely
as skies clear across eastern KS.
Latest shorter term models, HRRR and VSREF, strongly support
ifr/lifr fog forming over eastern KS later this evening and
gradually spreading east into far western MO. Have also noticed the
latest hourly LAMP data is trending towards slower clearing. So,
with this in mind have delayed clearing, but once clouds do clear
the likelihood for dense fog with lifr/vlifr visibilities increases
rapidly.
And there are some signs that suggest the stratus may not clear till
after sunrise Wednesday. Latest RUC 950mb condensation pressure
deficit prog hints at this.
Once the fog lifts we will see vfr conditions from late morning on.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
548 PM CST TUE NOV 22 2011
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
/247 PM CST Tue Nov 22 2011/
Concerns in the short term primarily deal with fog potential
overnight as well as temperatures on Thanksgiving.
Stratus behind a departing upper level shortwave continues to linger
across much of the region this afternoon; trapped under a low-level
shortwave ridge. There have been slight indications that drier low
level air is beginning to mix southeast however removing all the
stratus before sunset looks doubtful. The low-level ridge axis will
gradually slide southeast this evening, which may allow the western
zones to partially clear towards midnight and shift stratus eastward.
Given ample low level moisture, subsidence aloft, and very light
surface winds the development of radiation fog seems likely. Further
east, expecting stratus to linger much longer through the night, with
additional MVFR fog developing. Any breaks in the stratus would allow
for periods of dense fog to occur.
Wednesday: Mid-level heights will steadily build through the middle
portions of the week with surface high pressure moving southeast of
the CWA during the day on Wednesday. Morning fog will take a few
hours to mix out but strong warm air advection and a light south
wind should promote a climb into the 50s in most locations.
Thanksgiving: Weather conditions for Thanksgiving should end up being
almost spectacular. As upper level troughing moves into the Southwest
United States lee side troughing will begin to develop amplifying the
surface pressure gradient over Kansas and Missouri. Soundings suggest
we`ll mix up to around 900 mb by mid-afternoon, which should result
in middle to perhaps even upper 60s in most locations. There will be
a bit of concern for upper level cirrus especially with a deepening
southwest flow pattern aloft. Believe it or not, this could fall as
one of the warmest Thanksgiving holidays on record. The warmest
Thanksgivings ever recorded fell on 11/26/98, 11/24/1966, and
11/25/1926 all at 70 degrees.
Dux
Friday - Tuesday:
Models have shown good continuity bringing a front through Friday
evening/Friday night and there is only minor differences, for a four
day forecast, in timing. Strong warm and moist advection ahead of
the front combined with strong large scale forcing ahead of stout
trough should result in widespread rainfall across the area Friday
night. Confidence is high that it will rain throughout the region so
have bumped POPs up across the forecast area for this time frame.
Instability and lapse rates look fairly weak so have scaled back
thunder mention, especially during the Friday afternoon time frame
when the trough is still very removed from the region. Have
maintained thunder mention for the overnight period as forcing from
the trough combined with marginal lapse rates should produce some
thunder across the forecast area. Still think given the lack of/weak
instability that storms should be isolated in nature and not nearly
as widespread as the shower/rain activity.
Uncertainty really increases for the latter half of the weekend.
Ensembles from the GEFS to the ECMWF and the NAEFS have such a high
degree of variability with the upper level height fields it yields
minimal confidence that any one operational model is more correct
over anything else. If a trend can be determined it is that at some
point Sunday into Tuesday a trough or closed low will develop
somewhere over the eastern half of the CONUS. The intensity, timing
and location are all suspect at this point and as a result did not
deviate from the forecast initialization which keeps the region
relatively cool and dry for now. It also seems that this
troughing/closed low over the east may phase with a northern stream
system moving out of southern Canada that adds strength to the
trough/low giving it more longevity. This occurs as a ridge over the
western CONUS and eastern Pacific strengthens possibly setting up a
blocking pattern over North America.
CDB
&&
.AVIATION...
For the 00z TAFs, current thinking is mvfr stratus will be slower to
clear. While back edge of the stratus deck/clearing line
extrapolates to reach all 3 terminals by 05z-06z expect to see
fog/ifr stratus form across eastern KS where clouds clear, thus
delaying the clearing at the terminals. With surface winds becoming
nearly calm as the surface ridge edges east plus the moisture left
by last nights rains fog formation is becoming increasingly likely
as skies clear across eastern KS.
Latest shorter term models, HRRR and VSREF, strongly support
ifr/lifr fog forming over eastern KS later this evening and
gradually spreading east into far western MO. Have also noticed the
latest hourly LAMP data is trending towards slower clearing. So,
with this in mind have delayed clearing, but once clouds do clear
the likelihood for dense fog with lifr/vlifr visibilities increases
rapidly.
And there are some signs that suggest the stratus may not clear till
after sunrise Wednesday. Latest RUC 950mb condensation pressure
deficit prog hints at this.
Once the fog lifts we will see vfr conditions from late morning on.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1218 PM CST MON NOV 21 2011
.AVIATION...18Z KGRI TAF. LIGHT SOUTH WINDS ARE EXPECTED THROUGH
THE DAY WITH LIGHT AND VARIABLE WINDS TONIGHT. A LIGHT NORTHWEST
WIND IS THEN EXPECTED TO DEVELOP BY MID TUESDAY MORNING. MID TO
HIGH CLOUDS WILL QUICKLY MOVE INTO THE AREA THIS AFTERNOON AND
REMAIN THROUGHOUT MUCH OF THE PERIOD. HOWEVER...VFR CONDITIONS
WILL PERSIST THROUGH TOMORROW.
&&
.PREV DISCUSSION... /ISSUED 1144 AM CST MON NOV 21 2011/
UPDATE...FOR TONIGHT...12Z NAM AND GFS HAVE COME IN FURTHER SOUTH
WITH THE PRECIPITATION AND WARMER IN AREAS THAT ARE EXPECTED TO
SEE PRECIPITATION. IN ADDITION...THE 09Z SREF ENSEMBLES ARE
INDICATING LESS THAN A 5 PERCENT CHANCE OF 0.01 LIQUID
ACCUMULATION IN THE TRI CITIES...KEEPING ACCUMULATING RAIN TO THE
SOUTH OF THE TRI CITIES AND PRIMARILY OVER KANSAS. THE ENSEMBLE
MEAN TEMPERATURE IS AT OR ABOVE 32F FOR ALL LOCATIONS WITH POPS OF
15 PERCENT OR HIGHER...THIS IS PRIMARILY REFERRING TO KANSAS ZONES
AS THESE ARE ABOUT THE ONLY ZONES WITH HIGHER POPS. THEREFORE...THE
POSSIBILITY OF FREEZING RAIN LATE TONIGHT INTO EARLY TOMORROW
MORNING HAS DECREASED AND SEEMS UNLIKELY. CONSEQUENTLY...FREEZING
RAIN HAS BEEN PULLED FROM THE FORECAST AT LEAST FOR NOW...ALTHOUGH
IT WILL STILL BE A CLOSE CALL AND WILL BE CLOSELY WATCHED BY
FUTURE FORECAST SHIFTS.
PREV DISCUSSION... /ISSUED 515 AM CST MON NOV 21 2011/
SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS HASTINGS NE
1144 AM CST MON NOV 21 2011
.UPDATE...FOR TONIGHT...12Z NAM AND GFS HAVE COME IN FURTHER SOUTH
WITH THE PRECIPITATION AND WARMER IN AREAS THAT ARE EXPECTED TO
SEE PRECIPITATION. IN ADDITION...THE 09Z SREF ENSEMBLES ARE
INDICATING LESS THAN A 5 PERCENT CHANCE OF 0.01 LIQUID
ACCUMULATION IN THE TRI CITIES...KEEPING ACCUMULATING RAIN TO THE
SOUTH OF THE TRI CITIES AND PRIMARILY OVER KANSAS. THE ENSEMBLE
MEAN TEMPERATURE IS AT OR ABOVE 32F FOR ALL LOCATIONS WITH POPS OF
15 PERCENT OR HIGHER...THIS IS PRIMARILY REFERRING TO KANSAS ZONES
AS THESE ARE ABOUT THE ONLY ZONES WITH HIGHER POPS. THEREFORE...THE
POSSIBILITY OF FREEZING RAIN LATE TONIGHT INTO EARLY TOMORROW
MORNING HAS DECREASED AND SEEMS UNLIKELY. CONSEQUENTLY...FREEZING
RAIN HAS BEEN PULLED FROM THE FORECAST AT LEAST FOR NOW...ALTHOUGH
IT WILL STILL BE A CLOSE CALL AND WILL BE CLOSELY WATCHED BY
FUTURE FORECAST SHIFTS.
&&
.PREV DISCUSSION... /ISSUED 544 AM CST MON NOV 21 2011/
AVIATION...12Z KGRI TAF. VFR CONDITIONS ARE FORECAST. A SHORTWAVE
TROUGH MOVING INTO THE SOUTHERN PLAINS WILL LOWER CEILINGS TO MID-
LEVEL. NOT TOO FAR SOUTH OF THE TERMINAL THERE WILL BE MUCH LOWER
CEILINGS BETWEEN 06Z AND 12Z TUESDAY MORNING ALONG WITH THE
POSSIBILITY OF FREEZING RAIN. FOR NOW IT LOOKS LIKE PRECIPITATION
SHOULD REMAIN BARELY SOUTH OF THE TERMINAL...BUT CLOSE. WIND
SHOULD REMAIN LIGHT.
PREV DISCUSSION... /ISSUED 515 AM CST MON NOV 21 2011/
SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
544 AM CST MON NOV 21 2011
.AVIATION...12Z KGRI TAF. VFR CONDITIONS ARE FORECAST. A SHORTWAVE
TROUGH MOVING INTO THE SOUTHERN PLAINS WILL LOWER CEILINGS TO MID-
LEVEL. NOT TOO FAR SOUTH OF THE TERMINAL THERE WILL BE MUCH LOWER
CEILINGS BETWEEN 06Z AND 12Z TUESDAY MORNING ALONG WITH THE
POSSIBILITY OF FREEZING RAIN. FOR NOW IT LOOKS LIKE PRECIPITATION
SHOULD REMAIN BARELY SOUTH OF THE TERMINAL...BUT CLOSE. WIND
SHOULD REMAIN LIGHT.
&&
.PREV DISCUSSION... /ISSUED 515 AM CST MON NOV 21 2011/
SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
515 AM CST MON NOV 21 2011
.SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
.LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.PREV DISCUSSION... /ISSUED 1047 PM CST SUN NOV 20 2011/
AVIATION...06Z TAF. VFR CONDITIONS WILL BE IN PLACE AT THE START
OF THE TAF PERIOD. 11-3.9 MICRON SATELLITE IMAGERY SHOWS STRATUS
LOCATED ACROSS PARTS OF CENTRAL AND NORTHEAST KANSAS THAT HAS BEEN
SLOWLY MIGRATING NORTH. THE LATEST RUC SUGGESTS THE CLOUDS SHOULD
NOT MAKE IT AS FAR NORTH AS KGRI...SO WILL KEEP THOSE OUT OF THE
FORECAST FOR NOW. ATTENTION THEN SHIFTS TO AN UPPER LEVEL
DISTURBANCE THAT WILL MOVE INTO PARTS OF KANSAS MONDAY NIGHT.
AHEAD OF THE DISTURBANCE...MID AND HIGH LEVEL CLOUDS WILL
INCREASE...AND WILL SHOW A MID LEVEL CEILING FORMING AROUND 22Z.
WINDS WILL STAY LIGHT AND VARIABLE TONIGHT...BUT SHOULD TURN TO A
SOUTH/SOUTHEASTERLY DIRECTION LATE MONDAY MORNING INTO MONDAY
AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1047 PM CST SUN NOV 20 2011
.AVIATION...06Z TAF. VFR CONDITIONS WILL BE IN PLACE AT THE START
OF THE TAF PERIOD. 11-3.9 MICRON SATELLITE IMAGERY SHOWS STRATUS
LOCATED ACROSS PARTS OF CENTRAL AND NORTHEAST KANSAS THAT HAS BEEN
SLOWLY MIGRATING NORTH. THE LATEST RUC SUGGESTS THE CLOUDS SHOULD
NOT MAKE IT AS FAR NORTH AS KGRI...SO WILL KEEP THOSE OUT OF THE
FORECAST FOR NOW. ATTENTION THEN SHIFTS TO AN UPPER LEVEL
DISTURBANCE THAT WILL MOVE INTO PARTS OF KANSAS MONDAY NIGHT.
AHEAD OF THE DISTURBANCE...MID AND HIGH LEVEL CLOUDS WILL
INCREASE...AND WILL SHOW A MID LEVEL CEILING FORMING AROUND 22Z.
WINDS WILL STAY LIGHT AND VARIABLE TONIGHT...BUT SHOULD TURN TO A
SOUTH/SOUTHEASTERLY DIRECTION LATE MONDAY MORNING INTO MONDAY
AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 303 PM CST SUN NOV 20 2011/
SHORT TERM...TONIGHT THROUGH MONDAY. MAIN FORECAST CONCERN WILL BE
TEMPERATURES.
SATELLITE AND OBSERVATION INDICATES THAT CIRRUS CONTINUES TO SPREAD
ACROSS THE CENTRAL PLAINS THIS AFTERNOON. TEMPERATURES HAVE HAD A
LITTLE STRUGGLE TO CLIMB TODAY...BUT STILL ARE MAKING SOME PROGRESS.
SURFACE ANALYSIS HAS A RIDGE OF HIGH PRESSURE FROM MINNESOTA THROUGH
KANSAS...WHICH IS HELPING TO KEEP WINDS LIGHT AND TEMPERATURES COOL
ACROSS THE AREA.
THE SURFACE HIGH PRESSURE SYSTEM MOVES OFF TO THE EAST TONIGHT.
WINDS WILL GRADUALLY TURN TO THE SOUTH AND THERE IS A LITTLE WARM
ADVECTION ACROSS THE AREA DURING THE NIGHT. DESPITE THE WARM
ADVECTION TEMPERATURES SHOULD BE CLOSE TO WHAT THEY WERE LAST NIGHT
BUT MAYBE BIT WARMER. ON MONDAY THERE IS MORE WARM ADVECTION AND
TEMPERATURES ALOFT START TO WARM UP. EXPECT TEMPERATURES TO WARM UP.
AS THE SURFACE HIGH MOVES FURTHER EAST WINDS WILL TURN TO THE SOUTH.
THIS WILL HELP WARM THINGS UP...BUT WILL ALSO BRING SOME RETURN
MOISTURE AHEAD OF THE NEXT UPPER LEVEL WAVE THAT APPROACHES MONDAY
AFTERNOON. WILL CONTINUE TO KEEP THINGS DRY MONDAY AFTERNOON...BUT
THERE WILL BE AN INCREASE IN CLOUDS ACROSS THE AREA DURING THE DAY.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. MAIN CONCERN IN THE
EXTENDED WILL BE TEMPERATURE SWINGS ALONG WITH A COUPLE OF SMALL
CHANCES FOR PRECIPITATION.
LOOKING AT THE BIG PICTURE...VARIOUS EXTENDED MODELS SEEM TO BE IN
DECENT AGREEMENT OVER THE NEXT WEEK. THE FIRST SYSTEM WE WILL HAVE
TO DEAL WITH IS THE CLOSED MID LEVEL LOW PRESSURE JUST MOVING ONTO
THE PACIFIC COAST NEAR SFO. LATEST OPERATIONAL RUNS OF THE GFS AND
EC ALONG WITH ENSEMBLE SOLUTION CONTINUE TO SHOW THIS FEATURE
BECOMING MORE OF AN OPEN WAVE AS IT MOVES EAST OVER THE ROCKIES. THE
BEST FORCING AND MOISTURE LOOKS TO STAY SOUTH OF OUR CWA AS THIS
WAVE SWINGS THROUGH MONDAY NIGHT. SURFACE WINDS WILL SWITCH TO THE
NORTH AS SURFACE LOW TO OUR SOUTH MOVES EAST USHERING IN ANOTHER
BATCH OF COLDER AIR. THIS COULD BE AN ISSUE IN THE SOUTH AND
SOUTHEAST PART OF THE CWA AS FORECAST SOUNDINGS SHOWING AT LEAST A
SMALL CHANCE THAT ANY PRECIPITATION WE DO GET COULD BE IN THE FORM
OF FREEZING RAIN. THERE ARE STILL SOME QUESTIONS ABOUT THAT BUT
SINCE WE ALREADY HAVE A SLIGHT CHANCE OF FREEZING RAIN GOING IN THE
FORECAST...WILL NOT CHANGE ATTM. THIS LOOKS TO BE A QUICK HITTING
SYSTEM AND OPTED TO END PRECIP CHANCES BY 12Z TUESDAY. THE 09Z & 15Z
RUNS OF THE SREF MODEL STILL HANGING ONTO POPS IN THE SOUTH AND
SOUTHEAST DURING THE DAY ON TUESDAY BUT SEEMS TO ME IT IS LINGERING
THE PRECIP TOO FAR BEHIND THE TROUGH AXIS OF THE MID LEVEL WAVE.
AFTER THAT...TUESDAY AFTERNOON THROUGH THANKSGIVING LOOKING VERY
NICE ACROSS THE CENTRAL PLAINS AS A BROAD MID LEVEL HIGH PRESSURE
RIDGE BUILDS INTO THE ROCKIES AND CENTRAL PLAINS. HIGH TEMPERATURES
ON WED AND THU SHOULD BE IN THE UPPER 50S TO MID 60S...OR AROUND 10
TO 15 DEGREES ABOVE NORMAL FOR THIS TIME OF THE YEAR. THE ONLY
THING KEEPING THANKSGIVING FROM BEING A PERFECT DAY WILL BE THE
WINDS WHICH COULD BE A BIT GUSTY OUT OF THE SOUTH AS THE SURFACE
PRESSURE GRADIENT TIGHTENS UP OVER THE CWA DUE TO HIGH PRESSURE TO
OUR SOUTHEAST AND LOW PRESSURE DEVELOPING OVER THE LEE OF THE
ROCKIES.
RIDGE BEGINS TO BREAK DOWN FRIDAY AS NEXT SYSTEM APPROACHES THE
WESTERN U.S. COAST. ACTUALLY IT LOOKS LIKE A COUPLE OF SYSTEMS...ONE
MOVING INTO THE NORTHWEST AND ONE FURTHER SOUTH. THE EC IS PHASING
THESE SYSTEMS AS THEY MOVE EAST...PUSHING A HIGH AMPLITUDE TROUGH
ACROSS THE PLAINS FRIDAY NIGHT INTO THE WEEKEND. AT THIS TIME THE
MODELS PRODUCING MOST OF THE PRECIP TO OUR EAST BUT COULD BE SOME
LIGHT RAIN FRIDAY/FRIDAY NIGHT. THE BIGGER IMPACT WILL BE THE HIGH
TEMPERATURES WHICH WILL DROP BACK TO SEASONAL LEVELS BY NEXT
WEEKEND.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
911 PM EST TUE NOV 22 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 9 PM TUESDAY...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 /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...FAIRLY VIGOROUS FRONT WILL PASS THROUGH THE CWA TOWARD
MORNING. AHEAD OF THE FRONT...A BRIEF IFR CEILING IS
POSSIBLE...HOWEVER INSTABILITY AND DECENT MIXING WILL MAKE IT A
FAIRLY LOW PROBABILITY. STRONGEST OMEGA WILL BE JUST AHEAD OF THE
FRONT AND RACING EAST. THE HRRR MODEL HAS SOME CONVECTION WITH A
PRE-FRONTAL TROUGH MOVING RAPIDLY UP THE COAST...HOWEVER MOST OF THE
CONVECTION WILL STAY OFFSHORE. LOOK FOR GUSTY SOUTHWEST WINDS WITH
THE CONVECTION AS IT MOVES IN. VISIBILITIES AT THAT TIME WILL BE
NEAR IFR...WITH BRIEF IFR VISIBILITIES POSSIBLE IN BRIEF HEAVY RAIN.
LOOK FOR CONVECTION TO EXIT THE COAST BY 15Z. DO NOT EXPECT ANY
PRECIP BEHIND THE FRONT...AS DEEP MOISTURE STAYS EAST OF THE FRONTAL
BOUNDARY. POST FRONTAL...GRADUAL IMPROVEMENT TO VFR WITH GUSTY WEST
WINDS...BECOMING NORTHWEST. ALL TERMINALS WILL SCATTER BY LATE
MORNING.
EXTENDED OUTLOOK...EXPECT VFR THROUGH PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 9 PM TUESDAY...WIND SPEEDS BOTTOMED OUT AROUND 10 KNOTS AT
SUNSET AND ARE BEGINNING TO INCREASE AS A STRONG COLD FRONT
APPROACHES FROM THE WEST. ALL MODEL GUIDANCE IS INSISTENT THAT
LOW-LEVEL WINDS WILL CONTINUE TO INCREASE THROUGH THE NIGHT WITH
WIND SPEEDS JUST 2500 FT UP REACHING 50 KNOTS BY DAYBREAK. SINCE
THIS IS WARM AIR BLOWING OVER A RELATIVELY COOL OCEAN SURFACE WE
ONLY EXPECT HALF OF THAT WIND TO MIX DOWN...AND WIND SPEEDS ARE
FORECAST TO INCREASE TO 20-25 KT LATE TONIGHT. A LINE OF SHOWERS AND
EMBEDDED THUNDERSTORMS AHEAD OF THE FRONT SHOULD REACH THE COASTAL
WATERS JUST AFTER DAYBREAK.
SINCE WIND SPEEDS ARE JUST NOW BEGINNING TO INCREASE SEA HEIGHTS
HAVE NOT YET RESPONDED. SEAS ARE STILL RUNNING ONLY 3 FT AT THE
FRYING PAN SHOALS BUOY...AND 2 FT AT THE NEARSHORE CORMP BUOY. AN
EARLIER FORECAST UPDATE DELAYED THE START OF THE SMALL CRAFT
ADVISORY AND TRIMMED SEVERAL FEET OFF SEA HEIGHT FORECASTS FROM THIS
AFTERNOON...AND THIS IDEA STILL APPEARS TO BE WORKING OUT. BY
DAYBREAK WEDNESDAY SEAS SHOULD BE BUILDING TO 4-6 FT WITH SOME
7-FOOTERS POSSIBLE NEAR FRYING PAN SHOALS.
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...HDL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
633 PM EST TUE NOV 22 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 630 PM TUESDAY...A STRONG COLD FRONT EXTENDING FROM CENTRAL
TENNESSEE THROUGH MISSISSIPPI WILL MOVE EAST INTO THE CAROLINAS
WEDNESDAY BRINGING AN END TO THE RECORD WARMTH. AHEAD OF THE FRONT A
SQUALL LINE HAS DEVELOPED ACROSS PORTIONS OF GEORGIA AND ALABAMA
WITHIN A ZONE OF 500-1000 J/KG MUCAPE AND 50 KT 0-6 KM BULK SHEAR.
WHILE WE WILL EASILY SEE STRONG WIND SHEAR PARAMETERS HERE IN THE
EASTERN CAROLINAS LATE TONIGHT THE INGREDIENT IN DOUBT IS
INSTABILITY. THE 15Z SREF HAS ABOUT 60 PERCENT OF ITS MEMBERS WITH
500 J/KG OR GREATER MUCAPE AT 09Z/12Z WHEN THE SQUALL LINE WILL BE
MOVING INTO THE EASTERN CAROLINAS. GIVEN THE SYNOPTIC FORCING AND
STRONG SHEAR GUARANTEED TO OCCUR...500 J/KG INSTABILITY SHOULD
SUPPORT SHOWERS AND THUNDERSTORMS...SOME POSSIBLY SEVERE WITH
DAMAGING WINDS THE PRIMARY EXPECTED THREAT. THE LATEST HRRR RUN
MODELS ITS ARRIVAL ALONG I-95 AROUND 09Z...REACHING THE COAST
BETWEEN 10-11Z.
LOWS SHOULD OCCUR THIS EVENING WITHIN A FEW HOURS AFTER
SUNSET...WITH SLOWLY RISING TEMPERATURES EXPECTED OVERNIGHT AS THE
LOW-LEVEL WIND FIELDS ACCELERATE IN ADVANCE OF THE SQUALL LINE. 975
MB (1000 FT AGL) WINDS INCREASE FROM AROUND 10 KT THIS EVENING TO 30
KNOTS BY 09Z...WITH COMMENSURATE INCREASES IN SURFACE WIND SPEEDS AS
WELL.
&&
.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 /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...FAIRLY VIGOROUS FRONT WILL PASS THROUGH THE CWA TOWARD
MORNING. AHEAD OF THE FRONT...A BRIEF IFR CEILING IS
POSSIBLE...HOWEVER INSTABILITY AND DECENT MIXING WILL MAKE IT A
FAIRLY LOW PROBABILITY. STRONGEST OMEGA WILL BE JUST AHEAD OF THE
FRONT AND RACING EAST. THE HRRR MODEL HAS SOME CONVECTION WITH A
PRE-FRONTAL TROUGH MOVING RAPIDLY UP THE COAST...HOWEVER MOST OF THE
CONVECTION WILL STAY OFFSHORE. LOOK FOR GUSTY SOUTHWEST WINDS WITH
THE CONVECTION AS IT MOVES IN. VISIBILITIES AT THAT TIME WILL BE
NEAR IFR...WITH BRIEF IFR VISIBILITIES POSSIBLE IN BRIEF HEAVY RAIN.
LOOK FOR CONVECTION TO EXIT THE COAST BY 15Z. DO NOT EXPECT ANY
PRECIP BEHIND THE FRONT...AS DEEP MOISTURE STAYS EAST OF THE FRONTAL
BOUNDARY. POST FRONTAL...GRADUAL IMPROVEMENT TO VFR WITH GUSTY WEST
WINDS...BECOMING NORTHWEST. ALL TERMINALS WILL SCATTER BY LATE
MORNING.
EXTENDED OUTLOOK...EXPECT VFR THROUGH PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 PM TUESDAY...THE SMALL CRAFT ADVISORY HAS BEEN DELAYED BY
ABOUT 5 HOURS TO ACCOUNT FOR A MUCH SLOWER THAN INITIALLY FORECAST
INCREASE IN WIND SPEEDS AND WAVE HEIGHTS. THE SWAN FORECAST MODEL
INITIALLY USED EARLIER TODAY HAD EXTREMELY POOR INITIALIZATION.
ADJUSTING OUR FORECAST BY USING THE NOAA WAVEWATCH MODEL GAVE A MUCH
BETTER INITIALIZATION TO OUR FORECAST AND DELAYS THE ONSET OF 6-FOOT
WAVE HEIGHTS UNTIL VERY LATE TONIGHT...A FEW HOURS AFTER WIND SPEEDS
BEGIN TO INCREASE.
A STRONG COLD FRONT CURRENTLY EXTENDING FROM CENTRAL TENNESSEE
THROUGH MISSISSIPPI WILL RACE EAST AND TOWARD THE AREA WEDNESDAY. A
TIGHTENED PRESSURE GRADIENT IN ADVANCE OF THE FRONT WILL BE
RESPONSIBLE FOR THE STRONGER WINDS. A SQUALL LINE CURRENT AHEAD OF
THE FRONT ACROSS PORTIONS OF GEORGIA AND ALABAMA MAY DIMINISH IN
STRENGTH BUT IS EXPECTED TO REACH THE WATERS AROUND DAYBREAK
WEDNESDAY. STRONG GUSTY WINDS ARE THE PRIMARY EXPECTED THREAT WITH
ANY CONVECTION.
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...HDL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
705 AM EST MON NOV 21 2011
.SYNOPSIS...
OFFSHORE HIGH PRESSURE WILL EXTEND WESTWARD INTO EASTERN NORTH
CAROLINA THIS MORNING. A BACKDOOR COLD FRONT WILL SLIDE SOUTH
THROUGH EASTERN NORTH CAROLINA LATE TODAY AND TONIGHT THEN LIFT BACK
NORTH AS A WARM FRONT LATE TUESDAY. A COLD FRONT WILL MOVE THROUGH
FROM THE WEST LATE WEDNESDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT THURSDAY AND FRIDAY. THE HIGH WILL MOVE OFF THE COAST ON
SATURDAY. A MOIST COLD FRONT WILL APPROACH THE AREA SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 645 AM MONDAY...ADDED 20 POPS FOR ISOLD SHOWERS OVER NRN
SECTIONS THROUGH 10 AM. A FEW OBS INDICATE PCPN REACHING THE GROUND
WITH ACTIVITY CURRENTLY NE TO SW NEAR ECG-CLT LINE. ACTIVITY ASSCTD
WTIH INITIAL SHRT WV AND LATEST RUC13 ONLY MODEL TO PICK UP ON IT.
SOME BREAKS IN CLOUDS EXPECTED THIS AFTN AFTER SHRT WV MOVES THROUGH
AND STICKING WITH MAX TEMPS IN MID 70S INLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 330 AM MONDAY...LITTLE CHANGE TO PREVIOUS FCST WITH FRONT
PUSHING THROUGH BY EARLY EVENING...THEN STALLING TO S OVERNIGHT.
APPROACHING SHRT WV ACTIVITY AND DEVELOPING ISENT LIFT WILL PRODUCE
SLIGHT CHC OF PCPN OVER NRN HALF OF AREA OVERNIGHT. LATEST MOS GDNC
BLEND VERY CLOSE TO PREVIOUS FCST MIN TEMPS.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 3 AM MON...MAIN FEATURE OF INTEREST FOR THE LONG TERM WILL BE
A STRONG COLD FRONT THAT WILL SWEEP THROUGH E NC ON WED. MODELS IN
VERY GOOD AGREEMENT ON SYNOPTIC REGIME THROUGH THE END OF THE WEEK.
SFC BACK DOOR COOL FRONT WILL LIFT NORTH AS A WARM FRONT ON TUE.
OVERRUNNING WILL PRODUCE A STRATUS DECK AND POTENTIALLY A SHOWER OR
TWO MAINLY FOR NORTHEASTERN SECTIONS OF THE CWA. OTHERWISE A WARM
AND HUMID DAY IS ON TAP AS THE AREA WILL BE IN THE WARM SECTOR.
SIGNIFICANT SHORT WAVE TROUGH WILL APPROACH THE AREA ON TUE NIGHT
AND MOVE THROUGH ON WED. BOTH MID AND LOW LEVEL SUPPORT WILL BE
PRESENT FOR A PERIOD OF WIDESPREAD BUT SHORT DURATION RAINFALL.
PWATS AOA 1.5 INCHES AND GOOD BNDRY LAYER MOISTURE CONVERGENCE WILL
SET THE STAGE FOR RAIN. GENERALLY A HALF INCH OF RAIN IS EXPECTED ON
AVERAGE AS THE PRECIP WILL BE QUITE PROGRESSIVE. RAIN WILL ARRIVE
AROUND SUNRISE WED AND BE THROUGH THE BULK OF THE FA...SAVE FOR THE
COASTAL WATERS AND OBX...BY SHORTLY AFTER THE NOON HOUR. WITH THE
TIMING OF THE PRECIP MOVING THROUGH IN THE MORNING...LIMITED
POTENTIAL FOR SEVERE WEATHER AS INSTABILITY WILL BE LIMITED.
KINEMATICS WILL BE THERE FOR PERHAPS AN ISO STRONGER STORM AS LOW
LEVEL/DEEP LAYER SHEAR IS QUITE STRONG. GUSTY WINDS WILL BE THE MAIN
THREAT.
RAPID DRYING OF THE COLUMN WILL FOLLOW THE FROPA...AND BY WED
NIGHT TEMPS WILL PLUMMET INTO THE 30S FOR MOST AREAS ON CLEARING
SKIES. CAA WILL CONTINUE ON THANKSGIVING DAY WITH MAX T`S IN THE
UPR 50S WITH A BRISK NNW WIND. THE COOL DOWN WILL BE SHORT
LIVED...AS SFC HIGH WILL PROGRESS THROUGH AND RETURN FLOW WILL
DEVELOP ON FRI. CONDITIONS LOOK TO REMAIN DRY THROUGH THE EARLY
PART OF THE WEEKEND...WITH MODELS DIVERGING THEREAFTER. OPER GFS
IND STRONG SHORTWAVE BREAKING OFF FROM THE NORTHERN STREAM
WESTERLIES AND BECOMING CLOSED OFF IN THE SE CONUS...WHILE NCEP
AND ECM ENSEMBLE MEANS INDICATING A CONTINUED PROGRESSIVE
PATTERN. WILL SIDE WITH THE LATTER SOLN AND KEEP A VERY LOW CHANCE
POP TO ROUND OUT THE WEEKEND.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
/SHORT TERM THROUGH MONDAY EVENING/
AS OF 645 AM MONDAY...VFR SCU AND AC WDSPRD OVER AREA EARLY THIS
MORNING EXPECTED TO CONTINUE INTO AFTN. ISOLD SHOWERS ASSCTD WITH
SHRT WV WILL AFFECT NRN HALF OF AREA NEXT FEW HOURS BUT NOT EXPECTED
TO LIMIT VSBYS. A BACK DOOR COLD FRONT WILL DRIFT SOUTH ACROSS THE
REGION LATE TODAY WITH A CHANCE FOR MVFR CEILINGS TO DEVELOP IN THE
POST FRONTAL LOW LEVEL N-NE FLOW THIS EVENING...AND IFR LIKELY
OVERNIGHT.
/LONG TERM MONDAY NIGHT THROUGH FRIDAY/...
AS OF 3 AM MON...ANY LOW STRATUS/FOG SHOULD MIX OUT TO VFR MO CLOUDY
SKIES ON TUE AS SW BNDRY LAYER FLOW INCREASES AHEAD OF COLD FRONT
APPROACHING FROM THE WEST. CONDITIONS MAY DETERIORATE TUE NIGHT AS
THE BNDRY LAYER DECOUPLES ONCE AGAIN...AND PLENTIFUL LOW LEVEL
MOISTURE IS PRESENT. THIS REGIME WOULD FAVOR A LOW STRATUS
DEVELOPMENT AS INC HIGH AND MID LEVEL CLOUDS OVERRUN THE LOW LEVEL
MOISTURE. A STRONG COLD FRONT WILL SWEEP THROUGH ON WED...WITH A PD
OF WIDESPREAD RAIN AND TEMPO IFR CONDITIONS POSSIBLE. WINDS TURN
ABRUPTLY NW BEHIND THE FRONT ON WED AFTERNOON AND COULD BE A BIT
GUSTY. NNW GUSTY WINDS ARE EXPECTED ON FRI UNDER SUNNY SKIES.
&&
.MARINE...
/SHORT TERM THROUGH TONIGHT/...
AS OF 645 AM MONDAY...ADDED ISOLATED SHOWERS OVER NRN WATERS THIS
MORNING PER NEAR TERM UPDATE. NO CHANGES TO WINDS AND WAVES.
/PREVIOUS DISCUSSION/
AS OF 330 AM MONDAY...PREVIOUS FCST GENERALLY ON TRACK WITH WINDS
AROUND 15 KT OR LESS SHFTING FROM SW-W TO N-NE LATE AFTN THROUGH
EVENING AS BACKDOOR FRONT SLIDES ACROSS AREA. DID INCREASE WINDS
SLIGHLY OVER SRN WATERS AHEAD OF FRONT TODAY...AND ALL AREAS BEHIND
FRONT LATE TONIGHT WITH SLIGHTLY STRONGER SURGE INDICATED.
UPDATED SEAS WITH MODIFIED WW3. MAIN IMPACT WILL BE SOME HEIGHTS TO
AROUND 4 FT NRN WATERS LATE TONIGHT DUE TO STRONGER SURGE.
/LONG TERM TUESDAY THROUGH FRIDAY/...
AS OF 3 AM MON...WINDS WILL SHIFT TO EAST AND THEN SE ON TUE AS
FRONT RETREATS TO THE NORTH AS A WARM FRONT. THE WINDS SHOULD BE
LIGHT DURING THE DAY. GRADIENT INC TUE NIGHT AS APPROACHING COLD
FRONT MOVES INTO THE WESTERN CAROLINAS. WINDS VEER SW AND INC TO 15
KT...INC TO 20 KT WED MORNING. COOLER NEARSHORE WATERS WILL LIMIT
MIXING AND SHOULD CAP SUSTAINED WINDS AROUND 20 KT...WHERE AS HIGHER
WINDS EXPECTED OUT TOWARDS THE GULF STREAM. SCA CONDITIONS LIKELY
ALL OF THE WATERS WITH WIND GUSTS TOPPING 25 KT AND SEAS BUILDING
ABOVE 6 FT. THE FRONT SWEEPS OFFSHORE WED EVENING WITH WINDS VEERING
TO NW. CAA WILL COMMENCE AND WIND GUSTS COULD APPROACH GALE FORCE
FOR A PERIOD LATE WED NIGHT/EARLY THUR...ESPECIALLY ACROSS THE
NORTHERN AND CENTRAL WATERS. WINDS WILL DIMINISH BELOW SCA BY FRIDAY
AS HIGH PRES APPROACHES FROM THE WEST. SEAS WILL PEAK AROUND 9 FT IN
THE NRN WATERS EARLY THUR.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
702 PM EST TUE NOV 22 2011
.SYNOPSIS...
LOW PRESSURE OVER INDIANA WILL MOVE EAST ACROSS THE REGION TONIGHT
AND OFF THE NEW ENGLAND COAST ON WEDNESDAY. HIGH PRESSURE WILL
BUILD OVER THE REGION FOR THANKSGIVING DAY. THE HIGH PRESSURE AREA
WILL SETTLE SOUTHWARD OVER THE SOUTHEAST STATES INTO THE FIRST
PART OF THE WEEKEND AND PROVIDE FAIR MILD WEATHER.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
THE SYNOPTIC RAIN SHIELD HAS PROGRESSED INTO NW PA WHILE THE
SOUTHERN EDGE OF THE SHIELD IS MOVING INTO THE SOUTHWESTERN
COUNTIES NEAR MNN. THE DRY SLOT SHOULD PROGRESS ACROSS THE CENTRAL
AND EASTERN COUNTIES WHILE NW OHIO REMAINS MORE IN THE DEFORMATION
ZONE WITH STEADIER RAIN. WILL TAPER POPS THROUGH THE EVENING.
UNTIL ABOUT 04Z IN THE SOUTHERN AND EASTERN COUNTIES THERE IS A
SLIGHT CHANCE OF THUNDER AS INDICATED BY THE NAM AND HRRR WITH A
FEW HUNDRED JOULES OF ELEVATED CAPE. WILL MENTION A SLIGHT CHANCE
OF THUNDER UNTIL NEAR MIDNIGHT. EXPECT TEMPERATURES TO RISE THIS
EVENING AND REACH A MAX BEFORE MIDNIGHT AS THE WARM SECTOR OF THE
LOW PRESSURE AREA OVERSPREADS THE SOUTHERN AND EASTERN COUNTIES.
COLD ADVECTION WILL LOWER TEMPERATURES IN THE WAKE OF THE LOW BY
12Z. HAVE USED MAV GUIDANCE TEMPERATURES WITH MINOR CHANGES.
TWEAKED HOURLY TEMPERATURES TO REFLECT THE RISE THIS EVENING
ACROSS THE SOUTHEAST COUNTIES.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
ON WEDNESDAY LINGERING SHOWERS FROM THE EXITING LOW PRESSURE OVER
PA WILL QUICKLY MOVE OUT OF THE AREA DURING THE MORNING WITH
CLEARING MOVING IN RATHER QUICKLY. HAVE CHANCE POPS IN THE EAST
THIRD EARLY WITH DRY CONDITIONS BY AFTERNOON OVER THE ENTIRE CWA.
TEMPERATURES WILL RISE LITTLE IN THE EAST DUE TO LATER CLEARING
WHILE READINGS NEAR TOL WILL RECOVER TO NEAR 50.
THEN GENERALLY CLEAR WEATHER IS EXPECTED INTO THE WEEKEND WITH
GRADUALLY WARMING CONDITIONS. TEMPERATURES WILL BE SLIGHTLY ABOVE
NORMAL ON THANKSGIVINGS DAY AND WELL ABOVE NORMAL ON FRIDAY. HAVE
USED MAV/MET TEMPERATURES WITH SLIGHT ADJUSTMENTS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
WEEKEND WILL START OFF DRY AND MILD AS SOUTH TO SOUTHWEST FLOW
DEVELOPS AHEAD OF THE NEXT STORM SYSTEM. LOW PRESSURE IS PROGGED TO
MOVE NORTHEAST TO THE CENTRAL UNITED STATES FORCING A WARM FRONT
NORTH OF THE AREA. THE LOW WILL MOVE NORTHEAST TO ILLINOIS AND
INDIANA WHERE IT WILL STALL. THE SYSTEM WILL SPREAD RAIN INTO THE
REGION SATURDAY NIGHT AND CONTINUE INTO TUESDAY. THE LOW WILL THEN
MOVE NORTHEAST TO EASTERN LAKE ERIE BY TUESDAY AFTERNOON ALLOWING
COLD AIR ADVECTION TO TAKE PLACE. MODELS SUGGEST COLD AIR WILL BE
STRONG ENOUGH THAT SOME SNOW COULD MIX IN WITH THE RAIN BY LATE
TUESDAY AFTERNOON. WILL HOLD OFF ON MENTIONING SNOW AT THIS TIME DUE
TO TIMING ISSUES. COLD AIR ADVECTION MAY NOT ACTUALLY ARRIVE UNTIL
LATER TUESDAY NIGHT.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
SURFACE LOW IS ABOUT ON TRACK NEAR DAYTON AT 00Z AND MOVING EAST
NORTHEAST. THE LOW SHOULD BE NORTH OF PIT AT 09Z. MOST OF
NORTHERN OHIO AND NORTHWEST PA GETTING INTO A DRY SLOT AND THEN AS
THE LOW PASSES THE WINDS WILL SHIFT TO THE NORTHWEST WITH SOME
SHOWERS POSSIBLE. MAINLY IFR CEILINGS UNTIL SEVERAL HOURS AFTER FRONTAL
PASSAGE AND THEN CONDITIONS WILL IMPROVE. VFR CONDITIONS WILL
DEVELOP SLOWLY FROM WEST TO EAST WEDNESDAY. VFR WILL NOT REACH
EXTREME NORTHEAST OHIO AND NORTHWEST PA UNTIL DARK WEDNESDAY.
OUTLOOK...NON VFR SUNDAY.
&&
.MARINE...
THE LOW IN SOUTHERN INDIANA IS EXPECTED TO TRACK NE TOWARD ERIE THEN
EAST ACROSS PA TONIGHT AND WED MORNING. EAST WINDS SHOULD INCREASE
TO ABOUT 30 KNOTS THEN BACK TO NORTH THEN NW THROUGH WED MORNING
BEFORE STARTING TO DIMINISH. THE SCA CONDITIONS SHOULD END BY LATE
WED EVENING BUT THEY WILL PROBABLY REDEVELOP BY EARLY FRI MORNING AS
A SW FLOW INCREASES FOR A WHILE BEFORE DIMINISHING SOME BY LATE IN
THE DAY FRI.
MAINLY A SOUTH FLOW IS EXPECTED SAT AND MUCH OF SUN BUT DOES NOT
LOOK STRONG ENOUGH FOR A SCA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST WEDNESDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...REL
NEAR TERM...REL/OUDEMAN
SHORT TERM...
LONG TERM...LOMBARDY
AVIATION...KIELTYKA
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
644 PM EST TUE NOV 22 2011
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CONTINUE MOVING NORTHEAST THROUGH THE
OHIO VALLEY TONIGHT. AFTER A COLD FRONT PASSES THE
REGION...PRECIPITATION WILL COME TO AN END EARLY ON WEDNESDAY.
HIGH PRESSURE WILL BUILD IN THROUGH THE END OF THE
WEEK...PROVIDING FAIR CONDITIONS AND MOSTLY CLEAR SKIES.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
23Z UPDATE >
SCALED BACK THUNDER CHANCES EVEN FURTHER THAN THE LAST
UPDATE...AND MADE SOME TIMING ADJUSTMENT TO THE POPS TO ACCOUNT
FOR CURRENT TRENDS. THE EXPECTED NEAR-ZERO INSTABILITY IS LOOKING
MORE LIKE ZERO AT THIS TIME...WITH JUST A FEW CONVECTIVE LOOKING
SHOWERS APPEARING NEAR THE COLD FRONT IN INDIANA. NO OTHER
SIGNIFICANT CHANGES WERE MADE TO THE FORECAST.
PREVIOUS DISCUSSION >
SURFACE ANALYSIS CURRENTLY INDICATES THAT LOW PRESSURE IS CENTERED
NEAR INDIANAPOLIS...MOVING NORTHEAST TOWARD LAKE ERIE. THE SHIELD
OF STEADY PRECIPITATION (NORTH OF THE WARM FRONT) HAS SHIFTED
NORTH OF THE FORECAST AREA...WITH SCATTERED SHOWERS REMAINING IN
PLACE NEAR THE WARM FRONT AND INTO THE WARM SECTOR.
CONVECTIVE POTENTIAL LATE THIS AFTERNOON AND TONIGHT HAS BEEN THE
FOCUS OF THE FORECAST TODAY. THE THETA-E SURGE AHEAD OF THE
SURFACE LOW HAS BEEN WELL MODELED BY THE NAM12 IN TERMS OF SPATIAL
EXTENT AND TIMING...BUT OVERDONE IN TERMS OF MAGNITUDE. MOST OF
THE CWA WILL FIND ITS WAY INTO THE WARM SECTOR OVER THE NEXT FEW
HOURS (ESPECIALLY ALONG AND SOUTH OF THE
METEOROLOGICALLY-CONVENIENT I-71 CORRIDOR). WHAT THIS MEANS IN
TERMS OF CONVECTION IS NOT TOTALLY CLEAR. THE NAM12 CAPE
DEPICTIONS SHOW UP TO 500 J/KG...WITH MUCH MORE SUBDUED NUMBERS
COMING IN FROM THE OTHER MODELS (AROUND 200 J/KG ON THE RUC AND
GFS) AND LAPS ANALYSIS. 15Z SREF PROBS FOR >500 J/KG ARE UNDER 20
PERCENT. IN ADDITION...THE EXPECTED SOURCE REGION FOR CONVECTION
(ACCORDING TO THE HRRR RADAR SIMULATIONS) IS IN CENTRAL
KENTUCKY...WHERE RAIN HAS ESSENTIALLY PUT AN END TO
DESTABILIZATION. THUS...IT IS BELIEVED THAT INSTABILITY WILL BE
EXTREMELY LIMITED FOR THIS EVENT. WHILE IT IS TRUE THAT DYNAMIC
WEATHER SYSTEMS SUCH AS THIS ONE ARE CAPABLE OF DOING A LOT WITH A
LITTLE (IN TERMS OF INSTABILITY)...NEAR-ZERO VALUES ARE NOT GOING
TO SUPPORT A SEVERE WEATHER THREAT.
IT IS EXPECTED THAT...EMBEDDED WITHIN THE LARGER AREAS OF
RAIN...SOME WEAK CONVECTION MAY BE ABLE TO DEVELOP. THERE ARE
SIGNS (HRRR / SPC-WRF) OF THIS OCCURRING ALONG A PRE-FRONTAL
TROUGH WITHIN THE NEXT COUPLE HOURS...AND THEN AGAIN ALONG THE
COLD FRONT DURING THE MID TO LATE EVENING. THE DYNAMICS OF THE
SYSTEM ALONE WILL SUPPORT SOME GUSTY WINDS...EVEN OUTSIDE OF
STORMS. BEFORE THE RAIN MOVED IN...THERE WERE GUSTS TO AROUND 40
KNOTS IN THE LEXINGTON/FRANKFORT AREA OF KENTUCKY. HOWEVER...THIS
WILL BE AN EXCEPTION AND NOT A RULE. 50 KNOT WINDS ARE UP
THERE...BUT AT ABOUT 4000 FEET. IT WILL BE EXTREMELY DIFFICULT
(IF NOT IMPOSSIBLE) TO MIX TO ANYTHING THAT HIGH IN A MOIST...WARM
ADVECTING...PRECIPITATING PATTERN LIKE THIS.
ASIDE FROM A BRIEF DOWNPOUR IN A THUNDERSTORM...THE THREAT FOR
HEAVY OR PROLONGED RAINFALL HAS ENDED. TOTALS FROM THE RAIN TODAY
HAVE GENERALLY RANGED BETWEEN 1.00 AND 1.50 INCHES...NOT ENOUGH TO
GENERATE WIDESPREAD FLOODING. RISES ON A FEW RIVERS WILL BE
MONITORED (INCLUDING THE QUICK-RESPONDING OHIO BRUSH CREEK IN
ADAMS COUNTY...WHICH IS ALREADY IN FLOOD) BUT NO AREAL PRODUCTS
WILL BE NEEDED.
AS THE COLD FRONT MOVES AWAY FROM THE REGION...ADDITIONAL SHOWERS
WILL DEVELOP IN THE WRAP-AROUND COLD ADVECTION FLOW BEHIND THE
SURFACE LOW (AND ASSOCIATED WITH THE AXIS OF THE UPPER TROUGH).
ACCOUNTED FOR THIS WITH A PERIOD OF CHANCE POPS OVERNIGHT...WITH
EVERYTHING ELSE OTHERWISE TAPERED DOWN TO SLIGHT CHANCE OR DRY.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
THE UPPER TROUGH WILL BE MOVING AWAY FROM THE REGION ON WEDNESDAY
MORNING...BRINGING AN END TO PRECIPITATION NOT LONG AFTER THE
START OF THE FORECAST PERIOD. AN EXTENSIVE AREA OF HIGH PRESSURE
WILL THEN BUILD INTO THE EASTERN HALF OF THE COUNTRY...REMAINING
IN PLACE THROUGH THE END OF THE WEEK.
MODEL RH DEPICTIONS...EVEN WHEN CONSIDERING ALL LAYERS OF THE
ATMOSPHERE...ARE COMING IN QUITE DRY WITH THIS HIGH AND ITS
ASSOCIATED UPPER RIDGE. WILL KEEP SKY GRIDS IN THE CLEAR TO MOSTLY
CLEAR RANGE. THE FIRST CLEAR NIGHT (WEDNESDAY NIGHT) LOOKS TO BE
THE COLDEST...WITH SUB-FREEZING TEMPERATURES EXPECTED IN GOOD
RADIATIONAL COOLING CONDITIONS. TEMPERATURES SHOULD GRADUALLY
MODERATE THROUGH THE REST OF THE PERIOD...WITH NO MAJOR
DIFFERENCES DETECTED IN THE VARIOUS MODEL NUMBERS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE LONG TERM WILL START OUT DRY WITH HIGH PRESSURE ACROSS THE
AREA. WITH WARM SOUTHERLY FLOW ACROSS THE REGION TEMPERATURES WILL
BE WELL ABOVE NORMAL FOR FRIDAY AND SATURDAY. HIGH TEMPERATURES
WILL BE IN THE 60S ACROSS MOST LOCATIONS. A STRONG LOW PRESSURE
SYSTEM WILL APPROACH THE AREA SATURDAY EVENING AND WILL IMPACT THE
AREA THROUGH THE END OF THE LONG TERM PERIOD. THERE ARE SOME MODEL
TIMING DIFFERENCES HOWEVER THE LATEST ECMWF HAS COME INTO PRETTY
GOOD AGREEMENT WITH THE GFS. DUE TO THIS AGREEMENT WENT WITH A
BLEND. RAIN WILL BEGIN TO MOVE INTO THE AREA SATURDAY EVENING AND
WILL BE WIDESPREAD ACROSS THE AREA ON SUNDAY. THE UPPER LOW BECOMES
CUT OFF BY SUNDAY AND LINGERS NEAR THE AREA THROUGH THE MIDDLE OF
NEXT WEEK. THIS WILL ALLOW FOR PRECIPITATION TO LINGER ACROSS THE
AREA AS WELL. COLDER AIR WORKING INTO THE AREA WILL ALLOW FOR SOME
SNOW SHOWER ACTIVITY TO MIX IN AS WELL MONDAY NIGHT INTO TUESDAY.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
COLD FRONT WILL MOVE ACROSS THE TERMINALS THROUGH 04Z. NARROW BAND
OF SHOWERS ALONG THE FRONT WILL IMPACT SOME OF THE SITES. ONCE THE
FRONT PASSES THE WINDS WILL VEER AND BECOME GUSTY. CEILINGS WILL
LOWER TO MVFR AND THEN IFR AND REMAIN THAT WAY THROUGH THE NIGHT.
THERE COULD BE A FEW ADDITIONAL SHOWERS WRAPPING AROUND THE BACK
SIDE OF THE SYSTEM. WINDS WILL HAVE BECOME NORTHWEST BY DAYBREAK
BUT GUSTS WILL HAVE DIMINISHED. EXPECT CLOUDS TO CLEAR BETWEEN 12Z
AND 18Z.
OUTLOOK...MVFR CIGS/VSBYS POSSIBLE SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...NOVAK
AVIATION...
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
606 PM EST TUE NOV 22 2011
.SYNOPSIS...
LOW PRESSURE OVER INDIANA WILL MOVE EAST ACROSS THE REGION TONIGHT
AND OFF THE NEW ENGLAND COAST ON WEDNESDAY. HIGH PRESSURE WILL
BUILD OVER THE REGION FOR THANKSGIVING DAY. THE HIGH PRESSURE AREA
WILL SETTLE SOUTHWARD OVER THE SOUTHEAST STATES INTO THE FIRST
PART OF THE WEEKEND AND PROVIDE FAIR MILD WEATHER.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE SYNOPTIC RAIN SHIELD HAS PROGRESSED INTO NW PA WHILE THE
SOUTHERN EDGE OF THE SHIELD IS MOVING INTO THE SOUTHWESTERN
COUNTIES NEAR MNN. THE DRY SLOT SHOULD PROGRESS ACROSS THE CENTRAL
AND EASTERN COUNTIES WHILE NW OHIO REMAINS MORE IN THE DEFORMATION
ZONE WITH STEADIER RAIN. WILL TAPER POPS THROUGH THE EVENING.
UNTIL ABOUT 04Z IN THE SOUTHERN AND EASTERN COUNTIES THERE IS A
SLIGHT CHANCE OF THUNDER AS INDICATED BY THE NAM AND HRRR WITH A
FEW HUNDRED JOULES OF ELEVATED CAPE. WILL MENTION A SLIGHT CHANCE
OF THUNDER UNTIL NEAR MIDNIGHT. EXPECT TEMPERATURES TO RISE THIS
EVENING AND REACH A MAX BEFORE MIDNIGHT AS THE WARM SECTOR OF THE
LOW PRESSURE AREA OVERSPREADS THE SOUTHERN AND EASTERN COUNTIES.
COLD ADVECTION WILL LOWER TEMPERATURES IN THE WAKE OF THE LOW BY
12Z. HAVE USED MAV GUIDANCE TEMPERATURES WITH MINOR CHANGES.
TWEAKED HOURLY TEMPERATURES TO REFLECT THE RISE THIS EVENING
ACROSS THE SOUTHEAST COUNTIES.
&&
.SHORT TERM /6AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
ON WEDNESDAY LINGERING SHOWERS FROM THE EXITING LOW PRESSURE OVER
PA WILL QUICKLY MOVE OUT OF THE AREA DURING THE MORNING WITH
CLEARING MOVING IN RATHER QUICKLY. HAVE CHANCE POPS IN THE EAST
THIRD EARLY WITH DRY CONDITIONS BY AFTERNOON OVER THE ENTIRE CWA.
TEMPERATURES WILL RISE LITTLE IN THE EAST DUE TO LATER CLEARING
WHILE READINGS NEAR TOL WILL RECOVER TO NEAR 50.
THEN GENERALLY CLEAR WEATHER IS EXPECTED INTO THE WEEKEND WITH
GRADUALLY WARMING CONDITIONS. TEMPERATURES WILL BE SLIGHTLY ABOVE
NORMAL ON THANKSGIVINGS DAY AND WELL ABOVE NORMAL ON FRIDAY. HAVE
USED MAV/MET TEMPERATURES WITH SLIGHT ADJUSTMENTS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
WEEKEND WILL START OFF DRY AND MILD AS SOUTH TO SOUTHWEST FLOW
DEVELOPS AHEAD OF THE NEXT STORM SYSTEM. LOW PRESSURE IS PROGGED TO
MOVE NORTHEAST TO THE CENTRAL UNITED STATES FORCING A WARM FRONT
NORTH OF THE AREA. THE LOW WILL MOVE NORTHEAST TO ILLINOIS AND
INDIANA WHERE IT WILL STALL. THE SYSTEM WILL SPREAD RAIN INTO THE
REGION SATURDAY NIGHT AND CONTINUE INTO TUESDAY. THE LOW WILL THEN
MOVE NORTHEAST TO EASTERN LAKE ERIE BY TUESDAY AFTERNOON ALLOWING
COLD AIR ADVECTION TO TAKE PLACE. MODELS SUGGEST COLD AIR WILL BE
STRONG ENOUGH THAT SOME SNOW COULD MIX IN WITH THE RAIN BY LATE
TUESDAY AFTERNOON. WILL HOLD OFF ON MENTIONING SNOW AT THIS TIME DUE
TO TIMING ISSUES. COLD AIR ADVECTION MAY NOT ACTUALLY ARRIVE UNTIL
LATER TUESDAY NIGHT.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
RAIN QUICKLY SPREAD INTO THE REGION THIS MORNING AND EARLY
AFTERNOON QUICKLY CAUSING CEILINGS TO DROP DOWN TO IFR LEVELS.
VISIBILITIES BETWEEN IFR AND MVFR ARE ALSO OCCURRING IN THE RAIN.
MODERATE RAIN WILL CONTINUE TO SPREAD NORTH INTO THE REGION
THIS AFTERNOON. GFS MODEL INDICATES DRY SLOT WILL TRY TO WORK ITS
WAY NORTH INTO THE REGION THIS EVENING AND THIS SHOULD HELP TO CUT
SOME OF THE RAIN OFF FROM WEST TO EAST. LOW IS EXPECTED TO TRACK
NORTHEAST OVER THE REGION AND WE SHOULD SEE WINDS SHIFTING
GRADUALLY FROM A SOUTHEAST DIRECTION TO A NORTHWEST DIRECTION FROM
WEST TO EAST. IT WILL TAKE A LOT LONGER TO SEE A RETURN BACK TO
VFR CONDITIONS IN THE EAST COMPARED TO THE WEST TOMORROW.
OUTLOOK...NON VFR SUNDAY.
&&
.MARINE...
THE LOW IN SOUTHERN INDIANA IS EXPECTED TO TRACK NE TOWARD ERIE THEN
EAST ACROSS PA TONIGHT AND WED MORNING. EAST WINDS SHOULD INCREASE
TO ABOUT 30 KNOTS THEN BACK TO NORTH THEN NW THROUGH WED MORNING
BEFORE STARTING TO DIMINISH. THE SCA CONDITIONS SHOULD END BY LATE
WED EVENING BUT THEY WILL PROBABLY REDEVELOP BY EARLY FRI MORNING AS
A SW FLOW INCREASES FOR A WHILE BEFORE DIMINISHING SOME BY LATE IN
THE DAY FRI.
MAINLY A SOUTH FLOW IS EXPECTED SAT AND MUCH OF SUN BUT DOES NOT
LOOK STRONG ENOUGH FOR A SCA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST WEDNESDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...REL
NEAR TERM...REL/OUDEMAN
SHORT TERM...REL
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...ADAMS
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1041 PM CST SUN NOV 20 2011
.AVIATION.../FOR THE 00Z TAFS/
VFR CONDITIONS EXPECTED THROUGH 00Z TUESDAY WITH OCCASIONAL CEILINGS
NEAR BKN100-120. ONE CONCERN THAT NEEDS TO BE WATCHED WILL BE A
SLOWLY EXPANDING AREA OF STRATUS OVER SOUTHEAST MINNESOTA. WITH
LIGHT FLOW BELOW THE INVERSION THIS COULD CONTINUE TO ADVECT WEST
AND WHILE MORE THAN LIKELY GET STUCK ALONG AND EAST OF THE BUFFALO
RIDGE WILL ENCROACH FAIRLY CLOSELY TO SUX AND FSD FROM ABOUT 10Z TO
13Z. /08
&&
.DISCUSSION...
TOUGH UPDATE TONIGHT WITH WARM AIR ADVECTION AND CLOUD COVER
INCREASING ACROSS THE AREA OVERNIGHT. TEMPERATURES HAVE NOT FALLEN
MUCH THROUGH THE EVENING HOURS...AND HAVE BEGUN TO CREEP UPWARDS IN
A FEW LOCATIONS. HAVE LEFT SOME BREATHING ROOM ON THE BOTTOM END
FOR LOWS TONIGHT IN CASE LOCATIONS ARE ABLE TO DECOUPLE OVER THE
NEXT FEW HOURS...BUT IF THIS DOESN/T OCCUR EXPECT TO SEE A GENERAL
UPWARD TREND IN TEMPERATURES. BEST CHANCE OF DECOUPLING WILL BE IN
THE FAR EAST WHERE THE UPPER RIDGE WILL HANG ON FOR A FEW MORE
HOURS. SPEAKING OF THE EAST...STRATUS ALONG I-90 HAS SURGED BACK TO
JUST TO THE WEST OF ALBERT LEA MN AS OF 2Z. RUC SUGGESTS THIS IS
GOING TO CONTINUE TO BACK TO THE WEST THROUGHOUT THE NIGHT.
CEILINGS WITHIN STRATUS ARE FAIRLY LOW AND AM CONCERNED ABOUT FOG
POTENTIAL...BUT AFTER COLLABORATING WITH NEIGHBORING OFFICES TO THE
EAST OPTED TO LEAVE MENTION OUT OF THE FORECAST FOR NOW. INCREASED
SKY COVER IN FAR EAST..BUT THINK THE STRATUS WILL FIGHT WARM AIR
ADVECTION AND DRY AIR TO THE WEST AND WILL STRUGGLE ADVANCING MUCH
FURTHER WEST THAN FAR EASTERN TIER OF COUNTIES. UPDATE POSTED.
&&
.DISCUSSION.../ISSUED AT 307 PM CST/
MAIN FORECAST PROBLEM TONIGHT WILL BE LOW TEMPERATURES WHICH WILL
LIKELY OCCUR BEFORE MIDNIGHT BEFORE WARM AIR ADVECTION KICKS IN
ALONG WITH SOME INCREASE IN MID AND HIGH CLOUDS. WITH TEMPERATURES
IN TEENS AND 20S MOST PLACES THIS AFTERNOON...WILL NOT HAVE FAR TO
FALL WITH LIGHT WINDS...SO WILL GO LOWER THAN GUIDANCE...ESPECIALLY
SNOW COVERED AREAS...WITH STEADY OR SLOWLY RISING TEMPERATURES AFTER
MIDNIGHT AS LOW LEVEL SOUTHEASTERLY WINDS INCREASE.
A TREND OF SLOW WARMING WILL CONTINUE THROUGH LATE AFTERNOON ON
MONDAY...BUT WITH DECREASING WINDS IN THE EVENING...TEMPERATURES
WILL LIKELY DROP OFF QUICKLY BEFORE MIDNIGHT. HOWEVER...THE WARMER
AND MORE MOIST AIRMASS THAT WILL ADVECT INTO THE REGION ON MONDAY
SHOULD PREVENT OVERNIGHT LOWS FROM BOTTOMING OUT MUCH BELOW AVERAGE.
FOR THE REMAINDER OF THE WORK WEEK...TEMPERATURES WILL GENERALLY BE
ABOVE AVERAGE AS ZONAL FLOW BUILDS INTO A LONGWAVE RIDGE ACROSS THE
CENTRAL PLAINS. A SPLIT DISTURBANCE WILL MOVE THROUGH THE REGION ON
TUESDAY...BUT SHOULD NOT IMPACT THE FORECAST AREA EXCEPT FOR A
SLIGHT INCREASE IN CLOUD COVER ACROSS THE SOUTHEASTERN CORNER OF THE
CWA.
ON FRIDAY...A DEEP TROUGH WILL MOVE THROUGH THE REGION...BRINGING A
SURFACE COLD FRONT ACROSS THE PLAINS BY FRIDAY EVENING. CURRENTLY
PRECIPITATION CHANCES LOOK LOW...ESPECIALLY ACROSS THE WESTERN HALF
OF THE REGION WHERE FRONTAL PASSAGE WILL OCCUR EARLIER IN THE DAY
AND THE TEMPERATURE GRADIENT WILL NOT BE QUITE AS IMPRESSIVE.
MOISTURE WILL ALSO BE QUITE LIMITED EVEN AS THE FRONT MOVES THROUGH
NW IA AND SW MN...SO LEFT THE CHANCE OF PRECIPITATION FAIRLY LOW
THROUGHOUT THE EVENT. AFTER THE SYSTEM EXITS THE AREA ON SATURDAY
MORNING...TEMPERATURES WILL BRIEFLY RETURN TO NORMAL VALUES...WITH
NO ADDITIONAL PRECIPITATION EXPECTED THROUGH THE FORECAST PERIOD.
/LAFLIN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1003 PM CST TUE NOV 22 2011
.UPDATE...
SCATTED TO BROKEN STRATUS THAT HAS LINGERED SINCE THIS AFTERNOON
IS FINALLY SHOWING SIGNS OF ERODING NOW THAT DRIER AIRMASS/DEW
POINTS OVER OKLAHOMA ARE FILTERING ACROSS THE RED RIVER VALLEY.
PER LOOK AT THE RUC/NAM/NAMM/AND SREF FAMILIES ON BUFKIT AND
LOOKING AT CROSS-OVER TEMPERATURE METHOD...INDICATIONS ARE THAT
CURRENT TRENDS AND LOW TEMPERATURES FALLING TO...OR JUST BELOW
AFTERNOON DEW POINT TEMPERATURES. SUCH TRENDS SHOULD RESULT IN
PATCHY FOG DEVELOPMENT AS TEMPERATURES SLOWLY COOL THROUGH 3 AM
OR SO...THEN 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 HOUSTON/GALVESTON TX
1206 PM CST MON NOV 21 2011
.AVIATION...
ALTHOUGH THERE WILL BE SOME BRIEF BREAKS INTO VFR TODAY...THE
MAJORITY OF THIS PERIOD WILL BE MVFR WITH A LOWERING TO EARLY
TUESDAY IFR. A SHORT WINDOW OF CONVECTION TOMORROW MORNING INTO
AFTERNOON WITH PERIODS OF SHOWERS TRANSITIONING TO MODERATE RAIN
WITH EMBEDDED STORMS. NOT OVERLY CONFIDENT ON FREQUENCY NOR STRENGTH
OF STORMS AS RECENT MODELS HAVE A PROGRESSIVELY SE-MOVING THIN LINE
OF RAIN/TS ADVANCING INTO AN MARGINALLY UNSTABLE ENVIRONMENT (DRY
AIR ALOFT WITH A 5K FT WARM LAYER). THERE SHOULD BE ENOUGH FORCING
RIGHT ALONG A PRE-FRONTAL TROUGH TO PROVIDE THE VERY SHORT TERM
LIFT NEEDED TO WEAKEN (OR BREAK) THIS CAP SO HAVE PROB30`ED OR
TEMPO`ED THUNDER. A DECENT LOW LEVEL JET OF AROUND 35-30 KTS RIGHT
OFF THE SFC SHOULD TRANSFER DOWN WITHIN CONVECTION SO BEWARE OF
SUDDEN SW`ERN (SPEED) SHEAR IN THE LOWER 3K FT. TIMING HAS THIS
TSRA LINE PASSING ACROSS KCLL AT AROUND 15-16Z...METRO AROUND
NOON...TO THE COAST AROUND 20-22Z. KGLS MAY HAVE TUESDAY MORNING
PERIODS OF MVFR FOG...WITH A LESSER CHANCE OF DEVELOPING SEA FOG
THAT COULD QUICKLY DROP THE ISLAND INTO (L)IFR. 31
&&
.PREV DISCUSSION... /ISSUED 1031 AM CST MON NOV 21 2011/
UPDATE...
SEE MORNING UPDATE.
DISCUSSION...
AT 16Z...A COLD FRONT EXTENDED SOUTH FROM LONGVIEW TO PALASTINE TO
CALDWELL. THE FRONT APPEARS TO BE RETREATING NORTH AS THE TEMP AT
CLL WARMED FROM 66 TO 74 IN DURING THE LAST HOUR AND WINDS ARE
AGAIN OUT OF THE SOUTH. RADAR IS SHOWING GOOD COVERAGE OF LIGHT
SHOWERS...WITH GENERALLY TRACE AMOUNTS. WILL BUMP POPS TO CHANCE
OVER THE NORTHERN ZONES AS THE LATEST RUC AND NAM12 GUIDANCE SUPPORTS
AFTERNOON CONVECTION OVER THE NORTHERN ZONES ALONG THE COLD FORNT.
WILL MAINTAIN 20 POPS ELSEWHERE FOR STREAMER SHOWERS. ANY BREAKS
IN THE CLOUD COVER WILL ALLOW TEMPS TO WARM INTO THE LOWER AND
MIDDLE 80S. WILL KEEP TEMP FORECAST AS IS.
NAM 12 SHOWS MORE CAPPING OVER THE SOUTHERN HALF OF THE REGION ON
TUESDAY. GFS IS STILL ADVERTISING A GOOD SHOT OF RAIN AREAWIDE.
WILL WAIT ON THE CAN/ECMWF BEFORE CONTEMPLATING ANY CHANGES FOR
TUESDAY. 43
PREV DISCUSSION... /ISSUED 531 AM CST MON NOV 21 2011/
DISCUSSION...
UPDATED FOR 12Z TAF ISSUANCE
AVIATION...
SCATTERED SHOWERS ONGOING THIS MORNING ACROSS OUR NORTHWESTERN
COUNTIES IN THE VICINITY OF THE STATIONARY SURFACE FRONT WHICH IS
DRAPED JUST NORTH OF CLL. THIS FRONT SHOULD LIFT NORTHWARD LATER
THIS MORNING AND CIGS WILL LIFT AND SCATTER OUT TO VFR. A FEW SHOWERS
ARE POSSIBLE AGAIN TODAY BUT WILL NOT MENTION IN THE TAFS DUE TO
VERY ISOLATED NATURE. MVFR CIGS BUILD BACK IN QUICKLY AFTER SUNSET
THIS EVENING. HAVE INCLUDED MENTION OF CB FOR CLL AND IAH TUESDAY
MORNING TO ACCOUNT FOR EXPECTED SHOWER AND THUNDERSTORM ACTIVITY
AHEAD OF THE COLD FRONT WHICH WILL PUSH THROUGH THE REGION JUST
BEYOND THE CURRENT TAF PERIOD. 38
PREV DISCUSSION... /ISSUED 328 AM CST MON NOV 21 2011/
DISCUSSION...
LOW LEVEL JET CONTINUES TO TRANSPORT DEEP MOISTURE NORTH INTO SE TX
THIS MORNING. PWS ARE RUNNING AROUND 1.5 INCHES WITH SFC DEWPOINTS
IN THE LOWER 70S. COLD FRONT WAS LOCATED JUST NORTH OF THE CWA THIS
HOUR BETWEEN COLLEGE STATION AND HEARNE. THE FRONT IS EXPECTED TO
SAG SLOWLY SOUTHWARD THROUGH MID MORNING AND COULD BRIEFLY MOVE INTO
BURLESON...BRAZOS...AND MADISON COUNTIES. THE BOUNDARY WILL THEN
RETREAT BACK NORTH AS A WARM FRONT THIS AFTN. SCATTERED SHOWERS HAVE
DEVELOPED OVER THE NW ZONES DUE TO THE COMBINATION OF DEEP MOISTURE
AND CONVERGENCE ALONG THE FRONT. THIS ACTIVITY SHOULD DIMINISH BY
AFTERNOON AS THE FRONT STARTS TO RETREAT AWAY FROM THE AREA. STRONG
CAPPING IS EXPECTED TO KEEP ALL OF THE SIGNIFICANT CONVECTIVE
DEVELOPMENT NORTH OF THE AREA UNTIL LATE TONIGHT. ANOTHER
UNSEASONABLY WARM/HUMID DAY CAN BE EXPECTED TODAY WITH BREAKS IN THE
CLOUDS ALLOWING FOR NEAR RECORD HIGHS ONCE AGAIN. UPPER LOW NEAR THE
SOUTHERN CALIFORNIA COAST WILL MOVE EAST ACROSS THE SOUTHERN PLAINS
TONIGHT/TUESDAY. FRONT WILL PUSH SOUTH AGAIN AS A COLD FRONT TUESDAY
AS THE TROUGH APPROACHES. GIVEN THE PERSISTENT UPPER RIDGING OVER
THE GULF...PREFER THE SLOWER NAM SOLUTION WITH THE MOVEMENT OF THE
FRONT. THE FRONT WILL REACH THE NRN ZONES TUESDAY AFTN...HOUSTON
AREA EARLY TUESDAY EVENING...AND THE COAST LATE TUESDAY EVENING.
DEEP MOISTURE WILL POOL AHEAD OF THE FRONT WITH PWS 1.6-1.8 INCHES.
UPPER FLOW BECOMES MORE DIFFLUENT TUESDAY WITH SE TX IN THE RIGHT
REAR QUAD OF A JET MAX AT 300 MB. SPC HAS THE FAR NRN ZONES IN A
SLIGHT RISK TONIGHT...AND THE EASTERN 2/3 OF THE AREA IN A SLIGHT
RISK FOR TUESDAY. THE ATMOSPHERE WILL BE PLENTY UNSTABLE WITH LIS
AROUND -5 AND CAPES OF 1000-2000 J/KG. HOWEVER...SHEAR VALUES WILL
BE FAIRLY MARGINAL. THE 4KM NMM-WRF HAS THE BAND OF CONVECTION STILL
NW OF THE AREA AT 12Z TUESDAY...WHICH IS IN LINE WITH THE PREFERRED
SLOWER NAM SOLUTION. SO EXPECT THE BULK OF THE SHOWERS/THUNDERSTORMS
ON TUESDAY. WILL KEEP MENTION OF ISOLATED SEVERE AND LOCALLY HEAVY
RAINFALL IN THE HWOHGX. PATCHY SEA FOG HAS DEVELOPED OVER GALVESTON
BAY AND THE ADJACENT WATERS BUT VISIBILITIES HAVE MAINLY REMAINED
ABOVE 3 MILES. CURRENT THINKING IS THAT THE DENSE FOG WILL REMAIN
EAST OF THE AREA AS NOVEMBER IS CLIMATOLOGICALLY A BIT EARLY FOR
DENSE SEA FOG ALONG THE UPPER TEXAS COAST.
GRADUAL CLEARING CAN BE EXPECTED TUESDAY NIGHT AS SFC HIGH BUILDS
INTO SE TX IN THE WAKE OF THE FRONT. DRY AND PLEASANT CONDITIONS
ARE EXPECTED WEDNESDAY/THANKSGIVING DAY WITH SFC HIGH PRESSURE
RESULTING IN CLEAR SKIES AND SEASONABLE TEMPERATURES. THE UPPER
AIR PATTERN WILL REMAIN PROGRESSIVE WITH THE NEXT LONGWAVE TROUGH
APPROACHING FROM THE WEST LATE WEEK. 40 KT LOW LEVEL JET DEVELOPS
THURSDAY NIGHT/FRIDAY WHICH RESULTS IN A FAIRLY RAPID RETURN OF
MOISTURE TO THE AREA. PWS WILL REACH 1.6-1.8 INCHES AGAIN BY
FRIDAY. WILL SEE AN INCREASE IN CLOUD COVER AND WARMER/MORE HUMID
CONDITIONS THIS PERIOD. THE ATMOSPHERE BECOMES UNSTABLE ENOUGH TO
SUPPORT SCATTERED CONVECTIVE DEVELOPMENT BEGINNING FRIDAY AFTN.
ASSOCIATED COLD FRONT WILL PUSH ACROSS SE TX FRIDAY NIGHT/EARLY
SATURDAY WITH THE POSSIBILITY OF A SQUALL LINE ALONG THE FRONT.
HAVE LEANED TOWARD THE MORE PROGRESSIVE SOLUTIONS OF THE
GFS/CANADIAN/GFS ENSEMBLE MEAN WITH THE HANDLING OF THE TROUGH.
EXPECT SKIES TO CLEAR OUT SATURDAY AFTN WITH DRY/COOL WEATHER THE
REMAINDER OF THE WEEKEND.
RECORD HIGHS:
MON 11/21
CLL 85/1933
IAH 84/2007
HOU 84/2007
GLS 81/2004
RECORD HIGH MINS:
MON 11/21
CLL 67/1982
IAH 70/1909
HOU 69/2004
GLS 72/1965
35
MARINE...
WINDS AND SEAS CURRENTLY RUNNING JUST BELOW SCEC CRITERIA ACROSS THE
OFFSHORE WATERS. SCEC WILL LIKELY BE NEEDED THIS AFTERNOON AND
TONIGHT AS ONSHORE WINDS INCREASE ACROSS THE COASTAL WATERS. NEXT
COLD FRONT WILL MOVE OFFSHORE LATE TUESDAY BRINGING STRONG OFFSHORE
FLOW THROUGH MIDDAY WEDNESDAY. WINDS BECOME ONSHORE AGAIN BY LATE
THURSDAY AHEAD OF ANOTHER COLD FRONT EXPECTED TO ARRIVE NEXT
WEEKEND. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 69 77 47 71 48 / 40 60 10 0 0
HOUSTON (IAH) 70 81 51 71 50 / 20 60 20 0 0
GALVESTON (GLS) 71 79 56 70 56 / 20 60 30 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1031 AM CST MON NOV 21 2011
.UPDATE...
SEE MORNING UPDATE.
&&
.DISCUSSION...
AT 16Z...A COLD FRONT EXTENDED SOUTH FROM LONGVIEW TO PALASTINE TO
CALDWELL. THE FRONT APPEARS TO BE RETREATING NORTH AS THE TEMP AT
CLL WARMED FROM 66 TO 74 IN DURING THE LAST HOUR AND WINDS ARE
AGAIN OUT OF THE SOUTH. RADAR IS SHOWING GOOD COVERAGE OF LIGHT
SHOWERS...WITH GENERALLY TRACE AMOUNTS. WILL BUMP POPS TO CHANCE
OVER THE NORTHERN ZONES AS THE LATEST RUC AND NAM12 GUIDANCE SUPPORTS
AFTERNOON CONVECTION OVER THE NORTHERN ZONES ALONG THE COLD FORNT.
WILL MAINTAIN 20 POPS ELSEWHERE FOR STREAMER SHOWERS. ANY BREAKS
IN THE CLOUD COVER WILL ALLOW TEMPS TO WARM INTO THE LOWER AND
MIDDLE 80S. WILL KEEP TEMP FORECAST AS IS.
NAM 12 SHOWS MORE CAPPING OVER THE SOUTHERN HALF OF THE REGION ON
TUESDAY. GFS IS STILL ADVERTISING A GOOD SHOT OF RAIN AREAWIDE.
WILL WAIT ON THE CAN/ECMWF BEFORE CONTEMPLATING ANY CHANGES FOR
TUESDAY. 43
&&
.PREV DISCUSSION... /ISSUED 531 AM CST MON NOV 21 2011/
DISCUSSION...
UPDATED FOR 12Z TAF ISSUANCE
AVIATION...
SCATTERED SHOWERS ONGOING THIS MORNING ACROSS OUR NORTHWESTERN
COUNTIES IN THE VICINITY OF THE STATIONARY SURFACE FRONT WHICH IS
DRAPED JUST NORTH OF CLL. THIS FRONT SHOULD LIFT NORTHWARD LATER
THIS MORNING AND CIGS WILL LIFT AND SCATTER OUT TO VFR. A FEW SHOWERS
ARE POSSIBLE AGAIN TODAY BUT WILL NOT MENTION IN THE TAFS DUE TO
VERY ISOLATED NATURE. MVFR CIGS BUILD BACK IN QUICKLY AFTER SUNSET
THIS EVENING. HAVE INCLUDED MENTION OF CB FOR CLL AND IAH TUESDAY
MORNING TO ACCOUNT FOR EXPECTED SHOWER AND THUNDERSTORM ACTIVITY
AHEAD OF THE COLD FRONT WHICH WILL PUSH THROUGH THE REGION JUST
BEYOND THE CURRENT TAF PERIOD. 38
PREV DISCUSSION... /ISSUED 328 AM CST MON NOV 21 2011/
DISCUSSION...
LOW LEVEL JET CONTINUES TO TRANSPORT DEEP MOISTURE NORTH INTO SE TX
THIS MORNING. PWS ARE RUNNING AROUND 1.5 INCHES WITH SFC DEWPOINTS
IN THE LOWER 70S. COLD FRONT WAS LOCATED JUST NORTH OF THE CWA THIS
HOUR BETWEEN COLLEGE STATION AND HEARNE. THE FRONT IS EXPECTED TO
SAG SLOWLY SOUTHWARD THROUGH MID MORNING AND COULD BRIEFLY MOVE INTO
BURLESON...BRAZOS...AND MADISON COUNTIES. THE BOUNDARY WILL THEN
RETREAT BACK NORTH AS A WARM FRONT THIS AFTN. SCATTERED SHOWERS HAVE
DEVELOPED OVER THE NW ZONES DUE TO THE COMBINATION OF DEEP MOISTURE
AND CONVERGENCE ALONG THE FRONT. THIS ACTIVITY SHOULD DIMINISH BY
AFTERNOON AS THE FRONT STARTS TO RETREAT AWAY FROM THE AREA. STRONG
CAPPING IS EXPECTED TO KEEP ALL OF THE SIGNIFICANT CONVECTIVE
DEVELOPMENT NORTH OF THE AREA UNTIL LATE TONIGHT. ANOTHER
UNSEASONABLY WARM/HUMID DAY CAN BE EXPECTED TODAY WITH BREAKS IN THE
CLOUDS ALLOWING FOR NEAR RECORD HIGHS ONCE AGAIN. UPPER LOW NEAR THE
SOUTHERN CALIFORNIA COAST WILL MOVE EAST ACROSS THE SOUTHERN PLAINS
TONIGHT/TUESDAY. FRONT WILL PUSH SOUTH AGAIN AS A COLD FRONT TUESDAY
AS THE TROUGH APPROACHES. GIVEN THE PERSISTENT UPPER RIDGING OVER
THE GULF...PREFER THE SLOWER NAM SOLUTION WITH THE MOVEMENT OF THE
FRONT. THE FRONT WILL REACH THE NRN ZONES TUESDAY AFTN...HOUSTON
AREA EARLY TUESDAY EVENING...AND THE COAST LATE TUESDAY EVENING.
DEEP MOISTURE WILL POOL AHEAD OF THE FRONT WITH PWS 1.6-1.8 INCHES.
UPPER FLOW BECOMES MORE DIFFLUENT TUESDAY WITH SE TX IN THE RIGHT
REAR QUAD OF A JET MAX AT 300 MB. SPC HAS THE FAR NRN ZONES IN A
SLIGHT RISK TONIGHT...AND THE EASTERN 2/3 OF THE AREA IN A SLIGHT
RISK FOR TUESDAY. THE ATMOSPHERE WILL BE PLENTY UNSTABLE WITH LIS
AROUND -5 AND CAPES OF 1000-2000 J/KG. HOWEVER...SHEAR VALUES WILL
BE FAIRLY MARGINAL. THE 4KM NMM-WRF HAS THE BAND OF CONVECTION STILL
NW OF THE AREA AT 12Z TUESDAY...WHICH IS IN LINE WITH THE PREFERRED
SLOWER NAM SOLUTION. SO EXPECT THE BULK OF THE SHOWERS/THUNDERSTORMS
ON TUESDAY. WILL KEEP MENTION OF ISOLATED SEVERE AND LOCALLY HEAVY
RAINFALL IN THE HWOHGX. PATCHY SEA FOG HAS DEVELOPED OVER GALVESTON
BAY AND THE ADJACENT WATERS BUT VISIBILITIES HAVE MAINLY REMAINED
ABOVE 3 MILES. CURRENT THINKING IS THAT THE DENSE FOG WILL REMAIN
EAST OF THE AREA AS NOVEMBER IS CLIMATOLOGICALLY A BIT EARLY FOR
DENSE SEA FOG ALONG THE UPPER TEXAS COAST.
GRADUAL CLEARING CAN BE EXPECTED TUESDAY NIGHT AS SFC HIGH BUILDS
INTO SE TX IN THE WAKE OF THE FRONT. DRY AND PLEASANT CONDITIONS
ARE EXPECTED WEDNESDAY/THANKSGIVING DAY WITH SFC HIGH PRESSURE
RESULTING IN CLEAR SKIES AND SEASONABLE TEMPERATURES. THE UPPER
AIR PATTERN WILL REMAIN PROGRESSIVE WITH THE NEXT LONGWAVE TROUGH
APPROACHING FROM THE WEST LATE WEEK. 40 KT LOW LEVEL JET DEVELOPS
THURSDAY NIGHT/FRIDAY WHICH RESULTS IN A FAIRLY RAPID RETURN OF
MOISTURE TO THE AREA. PWS WILL REACH 1.6-1.8 INCHES AGAIN BY
FRIDAY. WILL SEE AN INCREASE IN CLOUD COVER AND WARMER/MORE HUMID
CONDITIONS THIS PERIOD. THE ATMOSPHERE BECOMES UNSTABLE ENOUGH TO
SUPPORT SCATTERED CONVECTIVE DEVELOPMENT BEGINNING FRIDAY AFTN.
ASSOCIATED COLD FRONT WILL PUSH ACROSS SE TX FRIDAY NIGHT/EARLY
SATURDAY WITH THE POSSIBILITY OF A SQUALL LINE ALONG THE FRONT.
HAVE LEANED TOWARD THE MORE PROGRESSIVE SOLUTIONS OF THE
GFS/CANADIAN/GFS ENSEMBLE MEAN WITH THE HANDLING OF THE TROUGH.
EXPECT SKIES TO CLEAR OUT SATURDAY AFTN WITH DRY/COOL WEATHER THE
REMAINDER OF THE WEEKEND.
RECORD HIGHS:
MON 11/21
CLL 85/1933
IAH 84/2007
HOU 84/2007
GLS 81/2004
RECORD HIGH MINS:
MON 11/21
CLL 67/1982
IAH 70/1909
HOU 69/2004
GLS 72/1965
35
MARINE...
WINDS AND SEAS CURRENTLY RUNNING JUST BELOW SCEC CRITERIA ACROSS THE
OFFSHORE WATERS. SCEC WILL LIKELY BE NEEDED THIS AFTERNOON AND
TONIGHT AS ONSHORE WINDS INCREASE ACROSS THE COASTAL WATERS. NEXT
COLD FRONT WILL MOVE OFFSHORE LATE TUESDAY BRINGING STRONG OFFSHORE
FLOW THROUGH MIDDAY WEDNESDAY. WINDS BECOME ONSHORE AGAIN BY LATE
THURSDAY AHEAD OF ANOTHER COLD FRONT EXPECTED TO ARRIVE NEXT
WEEKEND. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 86 69 77 47 71 / 30 40 60 10 0
HOUSTON (IAH) 83 70 81 51 71 / 20 20 60 20 0
GALVESTON (GLS) 77 71 79 56 70 / 10 20 60 30 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1153 PM CST SUN NOV 20 2011
.DISCUSSION...
SEE AVIATION FOR 06Z TAF DISCUSSION.
&&
.AVIATION...
LOW CLOUD FORMATION IS AHEAD OF SCHEDULE AS A WEAK COLD FRONT
CONTINUES TO CREEP SOUTHWARD TO NEAR A T82 TO GTU LINE AT 05Z.
GIVEN THIS TREND AND THE RUC SHOWING A SLIGHT PUSH FARTHER SOUTH
BEFORE RETREATING...WILL SHOW A NEAR FRONTAL ENVIRONMENT AT AUS
WITH SOME PATCHY DRIZZLE POSSIBLE FROM 12Z-18Z. CIGS JUST BEHIND
THE FRONT ARE RUNNING AT SIMILAR VALUES TO THOSE AHEAD OF THE
FRONT...BUT DEEPER INTO THE FRONTAL LAYER CIG HEIGHTS BECOME
MOSTLY IFR/LIFR OVER WEST CENTRAL TX. THUS WILL OFFER A 500 FT
CIG AND EXPECT SOME FLUCTUATIONS A FEW HUNDRED FEET WITH PATCHY
FOG AND DRIZZLE. SOUTH OF THE FRONT DRT/SAT/SSF SITES SHOULD
CONTINUE TO SEE A NEAR PERSISTENCE PATTERN OF MAINLY MFVR CIGS IN
THE OVERNIGHT HOURS THROUGH THE EARLY AFTERNOON. THE CENTRAL TX
FRONT IS EXPECTED TO DRIFT NORTHWARD WITH INCREASED LATE MORNING
SOUTHERLIES. AREAS OF SHOWERS ARE EXPCTED TO BE SIMILAR TO THAT OF
TODAY...AND A FEW THUNDERSTORMS COULD BECOME POSSIBLE AGAIN AFTER
22/00Z OVER THE NORTHERN HILL COUNTRY AS THE WEAK FRONT IS STILL
EXPECTED TO BE OVER CENTRAL TX.
&&
.PREV DISCUSSION... /ISSUED 922 PM CST SUN NOV 20 2011/
UPDATE...
MADE A QUICK UPDATE TO BRING BRING INTO THE FAR NRN CWA. LOADED
RUC WINDS INTO THE GRIDS WHICH HAS THE FRONT STALLING ACROSS THE
ONE COUNTY INTO THE NRN CWA OVERNIGHT. OTHERWISE ONGOING FORECAST
IN GOOD SHAPE.
PREV DISCUSSION... /ISSUED 301 PM CST SUN NOV 20 2011/
DISCUSSION...
MOIST...SOUTHEAST FLOW OFF THE GULF CONTINUES TONIGHT IN RESPONSE
TO PROGRESSIVE MOVE OF UPPER TROUGH INTO SOUTHERN/BAJA CALIFORNIA
ARIZONA. A FEW SHOWERS MAY DEVELOP OVER THE NORTHEAST CORRIDOR
TONIGHT...EITHER THIS EVENING IN RESIDUAL ISOLATED DAYTIME
INSTABILITY SHOWERS/SOUTHWARD PROPAGATION OF EXISTING STORMS IN
CENTRAL TEXAS OR CONVERGENT LATE NIGHT SHOWERS. LOWS TONIGHT WILL
RANGE FROM THE LOWER 60S HILLS TO THE LOW 70S ALONG THE I-35
CORRIDOR. THE APPROACHING TROUGH WEAKENS WHILE SWEEPING EASTWARD
ACROSS WEST AND NORTH TEXAS TOMORROW. STILL WEAK CAPPING ALOFT AND
RICH GULF MOISTURE IN THE LOWER LEVELS WILL RESULT IN SCATTERED
SHOWERS MAINLY HILL COUNTRY AND NORTHERN AREAS TOMORROW. HIGHS IN
THE UPPER 70S HILLS TO LOW AND MID 80S ADJACENT AREAS...EXCEPT
UPPER 80S SOUTHWEST. MODELS IN UNISON ON BRINGING A COLD FRONT
INTO THE AREA LATE TOMORROW NIGHT AND PUSHING IT SOUTHEAST OF THE
REGION BY MIDDAY TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL LINE THE FRONT LATE MONDAY NIGHT AND TUESDAY
MOST NUMEROUS OVER THE NORTHEAST CORRIDOR WHERE DYNAMICS AND
INSTABILITIES WILL BE BEST. A FEW STORMS MAY APPROACH SEVERE
LIMITS OVER NORTHERN PORTIONS OF THE HILL COUNTRY MONDAY NIGHT.
SHORT WAVE RIDGE PATTERN ALOFT SHIFTS EAST WITH A DRY SURFACE
RIDGE BUILDING SOUTH WEDNESDAY. LOW LEVEL MOISTURE WILL INCREASE
AHEAD OF THE NEXT SYSTEM ON THANKSGIVING WITH INCREASING CLOUDINESS.
HIGHS THANKSGIVING WILL BE MOSTLY IN THE 70S...LOWS GENERALLY IN
THE 40S WITH A FEW 30S HILL COUNTRY. AS THE SYSTEM PUSHES INTO
NORTHWEST TEXAS ON FRIDAY...A PACIFIC COLD FRONT WILL SLIDE INTO
WESTERN PORTIONS OF THE REGION. SHOWERS AND STORMS WILL AGAIN FORM
ALONG AND AHEAD OF THE FRONT FRIDAY AND FRIDAY NIGHT. A STRONGER
COLD FRONT WILL ARRIVE OVERNIGHT FRIDAY INTO EARLY SATURDAY
MORNING WITH CLEARING SKIES AND COLDER TEMPERATURES THROUGH NEXT
WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 72 82 67 80 50 / 20 30 60 30 -
AUSTIN BERGSTROM INTL AIRPORT 72 83 67 81 45 / 20 30 60 30 -
NEW BRAUNFELS MUNI AIRPORT 71 83 64 81 46 / 10 20 50 30 -
BURNET MUNI AIRPORT 68 79 64 77 47 / 30 40 60 20 -
DEL RIO INTL AIRPORT 64 82 59 81 47 / - 10 20 - -
GEORGETOWN MUNI AIRPORT 70 80 67 78 47 / 30 30 60 30 -
HONDO MUNI AIRPORT 67 84 63 83 43 / - 20 40 20 -
SAN MARCOS MUNI AIRPORT 72 82 66 79 47 / 10 20 50 30 -
LA GRANGE - FAYETTE REGIONAL 72 83 69 80 50 / 10 20 50 40 10
SAN ANTONIO INTL AIRPORT 70 83 66 81 49 / 10 20 40 30 -
STINSON MUNI AIRPORT 70 85 67 83 50 / - 20 40 30 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...01
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1131 PM CST SUN NOV 20 2011
.DISCUSSION...
KLBB HAS SLIPPED INTO IFR CONDITIONS WHILE KCDS REMAINS MVFR...BUT
IS EXPECTED TO SLOWLY DECREASE INTO IFR THROUGH EARLY MONDAY
MORNING. ALSO EXPECT TO SEE CHANCES FOR RAIN INITIALLY START OFF
AS DRIZZLE OR SHOWERS...BUT AS A STRONG STORM SYSTEM APPROACHES...
EXPECT TO SEE PRECIPITATION START TO INCREASE IN INTENSITY AND
COVERAGE THROUGH MONDAY MORNING. CANNOT RULE OUT SOME STRONG
STORMS AT THE TAF SITES WITH THE POSSIBILITY OF HAIL BUT IT
REMAINS TOO EARLY TO TELL WHEN OR WHERE THIS WILL OCCUR.
LIKEWISE...DO NOT EXPECT TO SEE CONTINUOUS PERIODS OF
PRECIPITATION BUT COVERAGE SHOULD BE ENOUGH TO WARRANT PREVAILING
CONDITIONS...AT LEAST FOR NOW. PRECIPITATION SHOULD DECREASE IN
INTENSITY AND CONDITIONS SHOULD IMPROVE BACK INTO THE MVFR RANGE
LATE IN THE AFTERNOON FROM WEST TO EAST AS THE STORM SYSTEM
DEPARTS THE AREA AND DRIER AIR WORKS INTO THE AREA FROM THE WEST.
VFR WILL RETURN TO KLBB BEFORE MIDNIGHT TUESDAY BUT JUST BEYOND
THE END OF THIS TAF CYCLE FOR KCDS.
JORDAN
&&
.AVIATION...
&&
.PREV DISCUSSION... /ISSUED 541 PM CST SUN NOV 20 2011/
AVIATION...
DIFFICULT FORECAST FOR THE TAF SITES FOR THE NEXT 24 TO 36 HOURS.
MVFR CEILINGS ARE EXPECTED TO DEVELOP AT BOTH TAF SITES SOMETIME
TONIGHT BUT THE EXACT TIME REMAINS HIGHLY UNCERTAIN. NEXT ISSUE IS
THE POSSIBILITY OF DRIZZLE AND/OR FOG DEVELOPMENT AT BOTH TAF SITES
WHICH WILL ALSO HELP TO BRING VISIBILITIES DOWN. OVERALL...IT
APPEARS THAT VFR-MVFR CONDITIONS WILL HOLD THROUGH MIDNIGHT LOCAL
TIME AND THEN GRADUALLY START TO DECREASE DOWN INTO IFR RANGE BY
SUNRISE AT BOTH SITES. IFR/MVFR CONDITIONS THEN EXPECTED TO
PERSIST INTO TOMORROW AS RAIN CHANCES INCREASE WITH THE APPROACH
OF A STORM SYSTEM FROM THE WEST. CONFIDENCE IN TIMING FOR ONSET OF
PRECIPITATION IS ALSO VERY LOW BUT EXPECT PRECIP CHANCES TO
PERSIST THROUGH MONDAY AFTERNOON. MAY SEE SOME BRIEF IMPROVEMENT
INTO SOLID MVFR RANGE LATE IN THE DAY MONDAY. EXPECT AMENDMENTS AS
CONDITIONS START TO EVOLVE THROUGH TONIGHT AND AS NEW WEATHER
INFORMATION ARRIVES.
JORDAN
PREV DISCUSSION... /ISSUED 247 PM CST SUN NOV 20 2011/
SHORT TERM...
MAIN FOCUS FOR THE SHORT TERM PERIOD IS THE IMPENDING WEST COAST
SYSTEM THAT WILL BRING CHANCES OF RAIN COMMENCING TOMORROW...AND
TAMPERING OFF TUESDAY MORNING.
THE PACIFIC UA LOW SYSTEM OF INTEREST WAS LOCATED OFF THE COAST OF
CENTRAL CALIFORNIA PER 20Z WATER VAPOR IMAGERY...AND PROGGED TO OPEN
UP AND EJECT QUICKLY ESE TO ACROSS THE DESERT SOUTHWEST MONDAY
MORNING...ACROSS THE SOUTH PLAINS MONDAY NIGHT AND EAST OF THE
REGION TUESDAY MORNING. THIS RELATIVELY QUICK TRAJECTORY IS BEING
HANDLED WELL BY THE NAM...GFS AND ECMWF SOLUTIONS...WITH PERHAPS THE
NAM BEING A TOUCH FASTER THAN THE LATTER MODELS. 20Z SFC ANALYSIS
DISPLAYED A COLD FRONT THAT SURGED SOUTH ACROSS THE CWA EARLIER THIS
MORNING...AND WAS SPATIALLY DISTRIBUTED FROM A NEAR PINE SPRINGS TO
FORT STOCKTON TO BRADY LINE. THUS LEAVING TEMPS IN THE 40S AND 50S
AND DEWPOINTS IN THE 20S AND 30S IN ITS WAKE. THIS PLACEMENT OF THE
SAID FRONT IS FARTHER SOUTH THAN WHAT MODELS PREDICTED 24 HOURS AGO.
THE GFS AND ECMWF ARE ONLY SLIGHTLY SIMILAR TO THE NAM IN REGARD TO
THE FRONT NOT BEING QUITE AS FAR SOUTH...HENCE THE CURRENT PLACEMENT
OF THE FRONT IS NOT HANDLED WELL BY EITHER AFOREMENTIONED SOLUTION
PER SE. HENCE...THE NAM AND RUC MODELS DISPLAY THE FRONT TRANSLATING
A BIT FARTHER SOUTH TONIGHT /THE RUC IS MOST AGGRESSIVE WITH THIS
POSSIBILITY/ BUT THE NAM AND TO A LESSER EXTENT THE GFS HAS A WARM
TONGUE OOZING IN ACROSS THE FAR SOUTHWESTERN ZONES.
IF FOLLOWING THE NAM SOLUTION WITH A SLIGHT RELIANCE ON THE GFS
SOLUTION...THE SUB-TROPICAL FETCH OF MOISTURE WILL CONTINUE TO SPILL
ACROSS THE SOUTH PLAINS AND THUS HIGH LEVEL CLOUDINESS WILL PREVAIL
THE REST OF TODAY AND TONIGHT. A 1025 SFC RIDGE WILL SETTLE IN NE OF
THE REGION AND INDUCE GENERALLY LIGHT EAST TO SOUTHEAST/UPSLOPE SFC
WINDS TONIGHT. AS A RESULT...LOW LEVEL MOISTURE WILL INCREASE AS
MODEL SOUNDINGS DISPLAYED PROGGED PWATS NEARING 1.00 INCH
PARTICULARLY ACROSS THE CENTRAL TO EASTERN SOUTH PLAINS. THE
SYNOPTIC LIFT IS NOT STRONG AT THIS POINT...BUT CURRENT THINKING IS
THAT LOW LEVEL STRATUS WILL DEVELOP FROM SOUTH TO NORTH WITH PERHAPS
ISENTROPIC UPGLIDE BEING ENOUGH TO INDUCE LIGHT DRIZZLE ACROSS THE
AFOREMENTIONED AREAS EARLY TOMORROW MORNING. AOA 12Z...INDICATIONS
OF LOCALIZED PATCHY FOG MAY DEVELOP AND LAST THROUGH MID-MORNING
ACROSS PORTIONS OF THE CWA...AS THE SYSTEM NEARS THE WESTERN FRINGES
OF THE SOUTH PLAINS. BY EARLY AFTERNOON...SYNOPTIC LIFT HAS
INCREASED AND MUCAPE VALUES IS ANTICIPATED TO NEAR 1000 J/KG
ESPECIALLY ACROSS EASTERN ZONES. THUS...ADEQUATE MUCAPE AND 0-6 KM
SHEAR VALUES NEARING 70 KTS MAY PROMOTE ISOLATED STRONG TO POSSIBLY
SEVERE THUNDERSTORMS WHERE HAIL IS THE PRIMARY THREAT...ACROSS
EASTERN ZONES DURING THE EARLY TO MID AFTERNOON. THE 15Z-00Z
TIME-FRAME APPEARS TO BE WHEN THE SYNOPTIC LIFT IS AT ITS
BEST...WITH A NOTICEABLE DECLINATION THEREAFTER. IT IS ALSO DURING
THE AFOREMENTIONED TIME-FRAME WHERE THE FRONT IS ANTICIPATED TO
RETREAT NORTH TO NEAR THE SOUTHEASTERN ZONES BEFORE THE PACIFIC
FRONT SWEEPS IN FROM WEST TO EAST...DRY SLOTTING THE REGION LATE
MONDAY NIGHT/EARLY TUESDAY MORNING. THUS THE OVERALL TREND APPEARS
TO BE LIGHT DRIZZLE EARLY MONDAY MORNING FOLLOWED BY INCREASING RAIN
CHANCES WITH HIGHEST POPS DISPLAYED 18Z-00Z ACROSS THE
EAST...COINCIDING WITH BEST SYNOPTIC LIFT AS THE SYSTEM COMMENCES TO
MOVE ACROSS THE REGION. THEREAFTER...PRECIP WILL DECLINE FROM WEST
TO EAST BY TUESDAY 12Z.
TEMPS OVER NIGHT TONIGHT WILL BE RELATIVELY MILD WITH MID TO UPPER
30S NORTH TO LOWER TO MID 40S SOUTH EXPECTED....AS HIGH-LEVEL
CLOUDINESS ENSUE AND EVENTUALLY LOW LEVEL STRATUS DEVELOPS. TEMPS
TOMORROW COULD BE A BIT TRICKY DEPENDING ON IF THE PACIFIC FRONT
MOVING IN FROM THE WEST DRY SLOTS THE AREA QUICKER THAN ANTICIPATED.
HOWEVER...WILL LEAN TOWARDS A RANGE OF UPPER 40S TO LOWER 50S NE TO
LOWER 60S SW AS HINTED AT BY MOS GUIDANCE.
LONG TERM...
TUES 12Z...THE COLD FRONT WILL BE NEARLY IF NOT ALL THE WAY THRU THE
FA...ALLOWING THE AREA TO DRY OUT. BY WED 06Z...SKIES WILL BE CLEAR
WITH LITTLE RESIDUAL MOISTURE LEFT IN THE LOW LVLS.
THEREFORE...EXPECT TEMPS TO FALL SOME OVERNIGHT ACROSS THE AREA.
THOUGH AS SRLY SFC FLOW RETURNS...THE SHORTWAVE RIDGING ALSO MOVES
INTO THE AREA. THIS WILL ALLOW FOR A BRIEF WARMING TREND AHEAD THE
NEXT UL TROF EXPECTED TO MOVE INTO THE REGION ON TURKEY DAY. THIS
TROF IS PROGGED TO BE FAIRLY LOW AMPLITUDE AS IT MOVE ACROSS THE FA
PREVENTING MUCH IN THE WAY OF MOISTURE RETURN. THEREFORE...WILL
CONTINUE THE DRY EXTENDED FORECAST. ALSO...WINDS ASSOCIATED WITH
THIS SYSTEM LOOK FAIRLY ROBUST /AOA 40KTS AT 850/ AND GIVEN DRY
CONDITIONS THERE CONTINUE TO BE SOME FIRE WEATHER CONCERNS. THAT
BEING SAID GIVEN THE TIMING CURRENTLY PROGGED THESE WINDS WILL RAMP
UP IN THE COLD AIR AND LATE IN THE DAY AS THE TROF PUSHES THRU THE
REGION. ALSO...AS THE TROF EXITS THE REGION A SECOND SURGE OF ENERGY
TRAVERSES THE TROF PUSHING A STRONG COLD FRONT THRU THE AREA
OVERNIGHT FRI.
MEADOWS
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 36 55 34 60 31 / 10 30 20 0 0
TULIA 35 51 36 60 32 / 20 50 20 0 0
PLAINVIEW 36 52 37 61 33 / 20 50 20 0 0
LEVELLAND 41 60 40 63 34 / 20 30 10 0 0
LUBBOCK 41 54 40 63 34 / 20 40 20 0 0
DENVER CITY 44 63 42 64 36 / 20 20 10 0 0
BROWNFIELD 43 62 41 63 36 / 20 30 10 0 0
CHILDRESS 36 49 39 65 36 / 20 70 40 0 0
SPUR 42 50 41 64 37 / 20 60 20 0 0
ASPERMONT 45 53 44 63 37 / 20 70 40 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/93/14
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1015 PM CST SUN NOV 20 2011
.UPDATE...
THE COLD FRONT CURRENTLY LIES NEAR A LINE FROM BURNET TO GROESBECK
TO ATHENS...AND IT CONTINUES TO SLOWLY PROGRESS SOUTH. LATEST RUC
GUIDANCE PUSHES THE FRONT NEARLY COMPLETELY THROUGH THE CWA EXCEPT
FOR MAYBE PART OF ANDERSON AND LEON COUNTY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE STILL OCCURRING WELL NORTH
OF THE FRONT FROM COMANCHE NORTH TO THE RED RIVER AND EAST OF
THERE. WILL FOLLOW THE RUC GUIDANCE WITH THE FRONT POSITION AND
PUSH THE FRONT THROUGH NEARLY THE ENTIRE CWA TONIGHT AND CONTINUE
A 40-50 PERCENT CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS
OVERNIGHT. THESE SHOWERS AND STORMS ARE OCCURRING IN AN UNSTABLE
ATMOSPHERE ABOVE THE FRONT WHERE SOUTH TO SOUTHWESTERLY WINDS
CONTINUE TO BRING MOISTURE AND ISENTROPIC LIFT OVER THE SHALLOW
FRONT.
FOR THE UPDATE...ADJUSTED THE FRONTAL POSITION IN THE GRIDS AND
ALSO HAD TO ADJUST DEWPOINTS AND TEMPERATURES OVERNIGHT. OVERNIGHT
LOWS WERE LOWERED SIGNIFICANTLY IN MANY PLACES.
WITH THE FRONT ADVANCING FARTHER SOUTH THAN EXPECTED...THIS HAS
SIGNIFICANT IMPACTS ON TOMORROW/S FORECAST. AS THE UPPER LEVEL
TROUGH CURRENTLY OVER CALIFORNIA CONTINUES TO MOVE EAST
TOMORROW...SURFACE CYCLOGENESIS WILL OCCUR OVER NORTHERN MEXICO.
THIS WILL HELP TO DRAW THE FRONT BACK NORTH AS A WARM FRONT BUT IT
DOES NOT APPEAR THAT THE CYCLOGENESIS WILL BE STRONG ENOUGH TO
DRAW THE FRONT PAST THE I-20 CORRIDOR. THE NEW 00Z NAM SOLUTION
SUPPORTS THIS AND HAVE ADJUSTED THE FORECAST TO CLOSELY FOLLOW THE
NAM FOR NOW. THE NAM BRINGS THE FRONT AS FAR NORTH AS A LAMPASAS
TO CORSICANA TO CANTON LINE TOMORROW AFTERNOON. THIS WOULD MEAN
THAT ALL LOCATIONS NORTH OF THE FRONT WOULD REMAIN ENTRENCHED IN
THE COLD AIR WHILE LOCATIONS SOUTH OF THE FRONT WARMED INTO THE
80S. HAVE ADJUSTED TOMORROW/S HIGH TEMPERATURES DOWN NORTH OF THE
FRONT WITH MOST OF THIS AREA REMAINING IN THE 50S.
RAIN AND POSSIBLY THUNDERSTORMS ARE STILL EXPECTED TO OCCUR NORTH
OF THE FRONT AS THE UPPER LEVEL SUPPORT ARRIVES...BUT FORECAST
SOUNDINGS FROM THE 00Z NAM NORTH OF THE FRONT DO NOT SHOW MUCH
ELEVATED INSTABILITY. THIS MAY LIMIT THE SEVERE POTENTIAL ACROSS
MOST OF THE NORTHERN HALF OF THE CWA TOMORROW. INSTEAD...THIS
REGION COULD JUST SEE A CHILLY RAIN TOMORROW. WILL CONTINUE TO
EVALUATE THE SEVERE THREAT AND LOCATION THROUGH THE NIGHT AS MORE
MODEL DATA ARRIVES. THE LOCATION OF THE FRONT WILL AGAIN PLAY A
CRITICAL FACTOR IN TOMORROW/S CONVECTIVE AND SEVERE WEATHER
POTENTIAL.
82/JLD
&&
.AVIATION...
MULTIPLE AVIATION WEATHER CONCERNS THROUGH MONDAY AFTERNOON WITH
MVFR CEILINGS/VISIBILITIES EXPECTED THROUGH THE EVENING...BECOMING
IFR AFTER SUNRISE MONDAY AND REMAINING IFR UNTIL MID AFTERNOON.
A COLD FRONT...CURRENTLY NEAR A LAMPASAS...WACO...CORSICANA...TO
EMORY LINE...WILL REMAIN NEARLY STATIONARY OVERNIGHT AND LIFT
NORTHWARD ON MONDAY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL BE POSSIBLE NEAR AND NORTH OF THE COLD FRONT OVERNIGHT WITH
STORM CHANCES INCREASING ON MONDAY AS THE FRONT LIFTS NORTH AND
LARGE SCALE LIFT INCREASES. THE BEST THUNDERSTORM CHANCES AT ALL
TAF SITES WILL BE MONDAY AFTERNOON/MONDAY NIGHT.
A NORTH/NORTHWEST WIND WILL PREVAIL AT ALL TAF SITES OVERNIGHT AT
SPEEDS BETWEEN 6 AND 12 KNOTS ALONG WITH SOME HIGHER GUSTS THIS
EVENING. THE WIND WILL SLOWLY TURN TO THE NORTHEAST/EAST ON MONDAY
AS THE FRONT BEGINS TO LIFT NORTHWARD AND EVENTUALLY BECOME
SOUTHEAST MONDAY AFTERNOON/EVENING.
79
&&
.PREV UPDATE...
.UPDATE...
THE IMMEDIATE THREAT FOR SEVERE WEATHER IN NORTH TEXAS APPEARS TO
BE WANING AND THUS HAVE CANCELLED THE WATCH FOR ALL OF NORTH
TEXAS. EXPECT THAT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE THROUGH THE NIGHT AND SOME OF THESE MAY PRODUCE
SMALL HAIL AND NUMEROUS CLOUD TO GROUND LIGHTNING STRIKES. THE 00Z
FWD SOUNDING SHOWS THE COLD FRONT TO BE CONFINED BELOW 925 MB OR
BELOW 3000 FT. ABOVE THE COLD FRONT THE ATMOSPHERE IS UNCAPPED AND
UNSTABLE BUT WEAK LAPSE RATES AND A LACK OF SIGNIFICANT
/UPWARD FORCING BEHIND THE FRONT IS LIKELY KEEPING THE SHOWERS
AND THUNDERSTORMS BELOW SEVERE LIMITS.
THE COLD FRONT IS MAKING AN IMPRESSIVE ADVANCEMENT SOUTH AND HAS
NOW PASSED THROUGH LAMPASAS AND PARTS OF NORTHERN BELL COUNTY. THE
WESTERN PORTION OF THE FRONT HAS MORE PUSH THAN THE EASTERN
SECTION AS THE FRONT THEN DRAPES TO THE NORTHEAST TOWARDS
CORSICANA AND EMORY. THE TEMPERATURE FORECAST FOR TONIGHT HAS BEEN
ADJUSTED BASED ON THIS LATEST POSITION BUT MAY NEED TO BE ADJUSTED
AGAIN DEPENDING ON HOW FAR SOUTH THE EASTERN PORTION ADVANCES.
WITH THE FRONT FARTHER SOUTH THAN PREVIOUS FORECAST...THIS COULD
AFFECT THE CONVECTIVE FORECAST FOR TOMORROW BUT WILL NOT BE MAKING
CHANGES AT THIS TIME.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 157 PM CST SUN NOV 20 2011/
...SEVERE THUNDERSTORM POTENTIAL CONTINUES ACROSS PORTIONS OF NORTH
TEXAS LATER THIS AFTERNOON AND AGAIN ON MONDAY AFTERNOON AND
EVENING...
OVERALL...THIS AFTERNOONS FORECAST PACKAGE CONTINUES THE TRENDS
MENTIONED IN PREVIOUS FORECASTS OVER THE PAST SEVERAL DAYS. THE
COLD FRONT IS RUNNING SLIGHTLY AHEAD OF PREVIOUS TIMING...BUT
FAIRLY CLOSE TO THE NAM AND RUC MODEL SOLUTIONS. AT 145 PM IT
EXTENDS FROM PARIS TO CLEBURNE TO SOUTH OF COMANCHE.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON THROUGH MID/LATE EVENING AS FORCING FOR ASCENT ARRIVES
FROM THE WEST AND HELPS WEAKEN THE STRONG CAP AROUND 860MB. VERY
MOIST AND UNSTABLE AIR AHEAD OF THE COLD FRONT WILL PRODUCE CAPES
500-1200 J/KG THIS EVENING AND 700-1400 J/KG ON MONDAY. BULK SHEAR
0-6KM WILL BE IN THE RANGE OF 40-60 KTS BOTH DAYS ALONG WITH
HELICITY VALUES GREAT THAN 200 M2/S2. AS PREVIOUSLY STATED...LARGE
HAIL WILL BE THE PRIMARY SEVERE THUNDERSTORM THREAT FOLLOWED BY
DAMAGING WINDS AND BRIEF ISOLATED TORNADOES. AREAS TO WATCH FOR
QUICK TORNADOGENESIS ARE...WHERE SURFACE WINDS ARE BACKED AND
THOSE CELLS THAT MOVE NEAR AND ALONG THE COLD FRONT. HAVE ADDED
SEVERE WORDING TO THE ZONE PACKAGE IN THIS RELEASE.
THE SYSTEM SHOULD MOVE OUT OF NORTH TEXAS LATE TUESDAY AFTERNOON
WITH FAIR WEATHER FOR WEDNESDAY AND THANKSGIVING DAY. OUR NEXT
SYSTEM WILL ARRIVE FRIDAY WITH ANOTHER ROUND OF THUNDERSTORMS AND
BENEFICIAL RAINFALL FOR NORTH TEXAS. THIS SYSTEM WILL MOVE RIGHT
ON THROUGH THE REGION AND SHOULD BE OUT OF NORTH TEXAS LATE FRIDAY
NIGHT. AFTERWARD...IT WILL BE DRY WITH SEASONAL TEMPERATURES OVER
THE WEEKEND. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 46 74 48 69 45 / 60 60 90 40 10
WACO, TX 52 80 56 75 44 / 60 40 80 50 10
PARIS, TX 49 81 55 68 44 / 60 60 90 60 10
DENTON, TX 45 69 46 66 41 / 60 70 90 20 5
MCKINNEY, TX 45 79 46 67 43 / 60 60 90 50 10
DALLAS, TX 47 78 49 70 47 / 60 50 90 50 10
TERRELL, TX 51 83 53 70 45 / 60 50 90 50 10
CORSICANA, TX 53 82 56 75 47 / 60 40 80 70 10
TEMPLE, TX 52 84 61 77 46 / 60 40 70 60 10
MINERAL WELLS, TX 43 64 42 68 40 / 40 70 90 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/82
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
536 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...TONIGHT AND WEDNESDAY
536 PM CST TUE NOV 22 2011
BIGGEST CONCERN IS ON CEILING HEIGHTS AND VISIBILITIES OVERNIGHT
AND THOUGH 15Z WEDNESDAY. AN EASTERLY SURFACE-925MB LOW LEVEL
LEVEL FLOW AROUND A LOW PRESSURE CENTER IN EASTERN INDIANA HAS
RESULTED IN A CORRIDOR OF CLEAR SKIES OVER WESTERN WISCONSIN INTO
SOUTHEAST MINNESOTA. BOTH TAF SITES ARE CURRENTLY IN THIS CLEAR
AREA. BOTH THE 22.18Z NAM AND 22.22Z RUC 925MB RELATIVE HUMIDITY
FIELDS ARE SHOWING THIS DRY WEDGE OF AIR. BOTH MODELS SHOW THIS
AREA FILLING IN OVERNIGHT AS THE LOW PUSHES FURTHER EAST. FOR NOW
HAVE KEPT CONSISTENCY FROM 18Z TAFS WITH IFR CEILINGS AT KRST
AROUND 05Z AND LOWER MVFR/UPPER IFR AT KLSE AROUND 08Z WITH
VISIBILITIES REMAINING IN THE MVFR CATEGORY. SOME CONCERN ON
VISIBILITIES ALSO DROPPING INTO THE IFR CATEGORY OVERNIGHT...WHICH
WOULD LIKELY HAPPEN IF STRATUS DOES NOT MOVE BACK IN AND THUS WILL
HAVE TO MONITOR CLOSE...BUT WITH KRST SITTING AT 4SM NOW DID LOWER
TO 2SM LATE TONIGHT. LOW LEVEL MOISTURE REMAINS IN PLACE THROUGH
MID MORNING WEDNESDAY...WITH THE LOWER CLOUD DECK SCATTERING OUT
BETWEEN 14Z- 16Z.
&&
.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 LA CROSSE WI
740 AM CST MON NOV 21 2011
.SHORT TERM...THROUGH WEDNESDAY
738 AM CST MON NOV 21 2011
PROFILERS ARE INDICATING THAT THE 925 MB WINDS HAVE BECOME MORE
SOUTHERLY THIS MORNING. THIS IS ALLOWING THE LOW LEVEL MOISTURE
WHICH IS TRAPPED BELOW THE INVERSION TO STREAM NORTHWARD FROM
IOWA. THESE CLOUDS ARE MEETING UP WITH SOME LOW CLOUDS THAT WERE
ALREADY LOCATED ACROSS THE AREA. MEANWHILE FAR EASTERN IOWA AND
NORTHERN ILLINOIS HAS LITTLE LOW LEVEL MOISTURE. BASED ON
THE LATEST RUC AND NAM/WRF...THINKING THAT MUCH OF THE AREA WILL
REMAIN MOSTLY CLOUDY TODAY. THE ONLY EXCEPTIONS WILL BE ACROSS
SOUTHWEST WISCONSIN AND POSSIBLY CENTRAL WISCONSIN WHERE THERE
MAY BE SOME SUNSHINE FROM TIME TO TIME THIS MORNING AND EARLY
AFTERNOON.
A STRONG SHORT WAVE TROUGH CURRENTLY OFF THE SOUTHERN CALIFORNIA
COAST WILL EJECT OUT TO THE NORTHEAST STARTING TODAY. AS IT DOES...
IT WILL BE COMING INTO A STRONGLY CONFLUENT FLOW OVER THE OHIO
VALLEY AND NORTHEAST PART OF THE COUNTRY. THIS IS EXPECTED TO
CAUSE THE WAVE TO WEAKEN AND TO TAKE ON A POSITIVE TILT WITH A
WEAK SURFACE LOW TRACKING THROUGH THE OHIO VALLEY. THE ECMWF IS
THE STRONGEST WITH THE SURFACE WAVE BUT THE NEW 21.00Z RUN HAS
BACKED OFF SOME ON THE STRENGTH OF THE SYSTEM AND DOES NOT HAVE
THE PRECIPITATION NEARLY AS FAR NORTH. THE 21.03Z SREF MEAN IS BY
FAR THE WEAKEST WITH THIS SYSTEM AND WOULD SUGGEST THAT ONLY FAR
SOUTHERN GRANT COUNTY HAS ANY CHANCE OF GETTING SOME
PRECIPITATION. THE 21.00Z NAM AND GFS ARE IN THE MIDDLE OF THESE
WITH JUST SOME LIGHT PRECIPITATION AS FAR NORTH AS MAYBE ELKADER
TO RICHLAND CENTER. THERE IS NOT A LOT OF FORCING ON THE NORTH
SIDE OF THIS SYSTEM WITH THE NAM AND GFS SHOWING AT MOST 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER ALONG WITH SOME
WEAK QG CONVERGENCE AND FRONTOGENESIS ABOVE 700 MB. WITH JUST SOME
WEAK FORCING...HAVE TRENDED THE FORECAST TOWARD THE WEAKER AND
MORE SOUTHERN SOLUTIONS AND CONFINED THE PRECIPITATION CHANCES TO
SOUTH OF A NEW HAMPTON TO ADAMS/FRIENDSHIP LINE.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
229 AM CST MON NOV 21 2011
STILL EXPECTING TO SEE A NICE WARM UP OCCURRING EARLY IN THE
PERIOD. HIGH PRESSURE WILL QUICKLY MOVE OFF TO THE EAST AND THE
RETURN LOW LEVEL FLOW WILL BRING WARMER AIR IN THE AREA. THE GFS
SUGGESTS 925MB TEMPERATURES WARMING TO AROUND 10C FOR THANKSGIVING
WITH A COLD FRONT EXPECTED TO COME ACROSS SOMETIME OVER THE
WEEKEND. THE MODELS HAVE DIVERGED ON THIS SYSTEM WITH THE ECMWF
BREAKING AWAY FROM THE CONSENSUS. THIS SYSTEM LOOKS TO BE A FULL
LONG WAVE TROUGH WITH EMBEDDED NORTHERN AND SOUTHERN STREAM SHORT
WAVE TROUGHS. THE ECMWF IS TRENDING TOWARD A STRONGER NORTHERN
STREAM SYSTEM THUS CAUSING THE LONG WAVE TROUGH TO TAKE ON A
POSITIVE TILT. IF THIS HAPPENS...THERE COULD BE LITTLE MOISTURE
RETURN AND NOT A LOT OF PRECIPITATION AS THE SYSTEM COMES THROUGH.
THE GFS AND 21.00Z GEM FOR NOW ARE HOLDING WITH THE IDEA OF THE
LONG WAVE TROUGH BEING STACKED WITH PRETTY MUCH EQUAL IN STRENGTH
NORTHERN AND SOUTHERN STREAM WAVES. THIS ALLOWS GULF MOISTURE TO
RETURN WITH SOME DECENT PRECIPITATION POSSIBLE. FOR NOW...HAVE
STAYED WITH THE NON ECMWF CONSENSUS SUGGESTING A PRETTY HIGH
PROBABILITY OF PRECIPITATION FOR FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION...TODAY AND TONIGHT
738 AM CST MON NOV 21 2011
PROFILERS ARE INDICATING THAT THE 925 MB WINDS HAVE BECOME MORE
SOUTHERLY THIS MORNING. THIS IS ALLOWING THE LOW LEVEL MOISTURE
WHICH IS TRAPPED BELOW THE INVERSION TO STREAM NORTHWARD FROM
IOWA. THESE CLOUDS ARE MEETING UP WITH SOME LOW CLOUDS THAT WERE
ALREADY LOCATED ACROSS THE AREA. THE 21.06Z NAM/WRF SEEMS TO HAVE
A GOOD HANDLE ON THESE CLOUDS AND IT SUGGESTS THAT BOTH TAFS SITE
WILL LIKELY CONTINUE TO SEE A MVFR DECK THROUGH THIS EVENING...
AND THEN MAY BECOME IFR OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
738 AM CST MON NOV 21 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...04
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
550 AM CST MON NOV 21 2011
.SHORT TERM...THROUGH WEDNESDAY
229 AM CST MON NOV 21 2011
MAIN FORECAST CONCERN IS WITH THE PRECIPITATION CHANCES FOR
TUESDAY.
SURFACE ANALYSIS THIS MORNING SHOWS HIGH PRESSURE CENTERED OVER
SOUTHERN ONTARIO WITH THE RIDGE AXIS EXTENDING SOUTHWEST INTO
NEBRASKA.
CLOUDS TODAY WILL BE PROBLEMATIC AS A STRATUS DECK THAT WAS OVER
THE REGION SUNDAY HAS YET TO CLEAR THE REGION. AS THE SURFACE HIGH
PULLS AWAY FROM THE AREA...THE LOW LEVEL WINDS WILL COME AROUND
MORE TO THE SOUTH. THIS SHOULD AT SOME POINT PUSH THIS STRATUS
DECK FARTHER TO THE NORTH BUT WHEN THIS OCCURS AND HOW FAR NORTH
THE CLOUDS GET IS QUESTIONABLE. FURTHER COMPLICATING
THINGS...ANOTHER STRATUS DECK RESIDES OVER MISSOURI...EXTREME
SOUTHERN IOWA INTO CENTRAL ILLINOIS. AS THE LOW LEVEL FLOW TURNS
TO THE SOUTH...THIS DECK COULD ALSO START MAKING A MOVE TOWARD THE
AREA. ALSO...SOME MID LEVEL MOISTURE AND CLOUDS ARE EXPECTED TO
STREAM IN FROM THE SOUTHWEST AND HAVE GONE WITH A MORE
PESSIMISTIC FORECAST HOLDING THE CLOUDS IN DURING THE MORNING
BEFORE SLOWLY DECREASING THEM THROUGH THE AFTERNOON.
A STRONG SHORT WAVE TROUGH CURRENTLY OFF THE SOUTHERN CALIFORNIA
COAST WILL EJECT OUT TO THE NORTHEAST STARTING TODAY. AS IT DOES...
IT WILL BE COMING INTO A STRONGLY CONFLUENT FLOW OVER THE OHIO
VALLEY AND NORTHEAST PART OF THE COUNTRY. THIS IS EXPECTED TO
CAUSE THE WAVE TO WEAKEN AND TO TAKE ON A POSITIVE TILT WITH A
WEAK SURFACE LOW TRACKING THROUGH THE OHIO VALLEY. THE ECMWF IS
THE STRONGEST WITH THE SURFACE WAVE BUT THE NEW 21.00Z RUN HAS
BACKED OFF SOME ON THE STRENGTH OF THE SYSTEM AND DOES NOT HAVE
THE PRECIPITATION NEARLY AS FAR NORTH. THE 21.03Z SREF MEAN IS BY
FAR THE WEAKEST WITH THIS SYSTEM AND WOULD SUGGEST THAT ONLY FAR
SOUTHERN GRANT COUNTY HAS ANY CHANCE OF GETTING SOME
PRECIPITATION. THE 21.00Z NAM AND GFS ARE IN THE MIDDLE OF THESE
WITH JUST SOME LIGHT PRECIPITATION AS FAR NORTH AS MAYBE ELKADER
TO RICHLAND CENTER. THERE IS NOT A LOT OF FORCING ON THE NORTH
SIDE OF THIS SYSTEM WITH THE NAM AND GFS SHOWING AT MOST 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER ALONG WITH SOME
WEAK QG CONVERGENCE AND FRONTOGENESIS ABOVE 700 MB. WITH JUST SOME
WEAK FORCING...HAVE TRENDED THE FORECAST TOWARD THE WEAKER AND
MORE SOUTHERN SOLUTIONS AND CONFINED THE PRECIPITATION CHANCES TO
SOUTH OF A NEW HAMPTON TO ADAMS/FRIENDSHIP LINE.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
229 AM CST MON NOV 21 2011
STILL EXPECTING TO SEE A NICE WARM UP OCCURRING EARLY IN THE
PERIOD. HIGH PRESSURE WILL QUICKLY MOVE OFF TO THE EAST AND THE
RETURN LOW LEVEL FLOW WILL BRING WARMER AIR IN THE AREA. THE GFS
SUGGESTS 925MB TEMPERATURES WARMING TO AROUND 10C FOR THANKSGIVING
WITH A COLD FRONT EXPECTED TO COME ACROSS SOMETIME OVER THE
WEEKEND. THE MODELS HAVE DIVERGED ON THIS SYSTEM WITH THE ECMWF
BREAKING AWAY FROM THE CONSENSUS. THIS SYSTEM LOOKS TO BE A FULL
LONG WAVE TROUGH WITH EMBEDDED NORTHERN AND SOUTHERN STREAM SHORT
WAVE TROUGHS. THE ECMWF IS TRENDING TOWARD A STRONGER NORTHERN
STREAM SYSTEM THUS CAUSING THE LONG WAVE TROUGH TO TAKE ON A
POSITIVE TILT. IF THIS HAPPENS...THERE COULD BE LITTLE MOISTURE
RETURN AND NOT A LOT OF PRECIPITATION AS THE SYSTEM COMES THROUGH.
THE GFS AND 21.00Z GEM FOR NOW ARE HOLDING WITH THE IDEA OF THE
LONG WAVE TROUGH BEING STACKED WITH PRETTY MUCH EQUAL IN STRENGTH
NORTHERN AND SOUTHERN STREAM WAVES. THIS ALLOWS GULF MOISTURE TO
RETURN WITH SOME DECENT PRECIPITATION POSSIBLE. FOR NOW...HAVE
STAYED WITH THE NON ECMWF CONSENSUS SUGGESTING A PRETTY HIGH
PROBABILITY OF PRECIPITATION FOR FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION...TODAY AND TONIGHT
549 AM CST MON NOV 21 2011
THE CLOUD FORECAST THROUGH MID AFTERNOON IS PROBLEMATIC AS LOW
LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH AN INVERSION. THIS
MOISTURE HAS BEEN QUITE PREVALENT ALONG AND NORTH OF THE
INTERSTATE 90 CORRIDOR. MEANWHILE SOME CLEARING HAS BEEN EVIDENT
IN THE SATELLITE FOG PRODUCT AND THE IN THE OBSERVATIONS ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. IN ADDITION...PATCHY AREAS
OF DENSE FOG HAVE DEVELOPED ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. KRST HAS BEEN IN THIS DENSE FOG SINCE 210852Z.
CURRENT THINKING IS THAT WITH THE LIGHT WINDS THAT THIS DENSE FOG
WILL LIKELY CONTINUE THERE THROUGH AT LEAST 21.15Z.
FOR LATE THIS MORNING AND EARLY AFTERNOON...THE MODELS CONTINUE TO
SUGGEST THAT THERE WILL BE SOME BRIEF CLEARING. HOWEVER THE ACTUAL
CONFIDENCE THAT THIS MAY ACTUALLY OCCUR IS LOW. AT THE MOMENT
CONCERNED ABOUT THE MVFR STRATUS SPREADING RAPIDLY NORTHWARD
ACROSS SOUTHERN IOWA. THE LATEST RUC SUGGESTED THAT THESE CLOUDS
WOULD NOT REACH KRST UNTIL 21.21Z AND KLSE AROUND 21.23Z...BUT
LIKE THE CURRENT CLOUDS THE MODELS ARE NOT PERFORMING THAT WELL.
WILL HAVE TO MONITOR THESE CLOUD TRENDS CLOSELY TODAY.
ONCE THESE CLOUDS MOVE BACK IN THEY WILL LIKELY LINGER THROUGH
TONIGHT. THERE MAY BE EVEN SOME IFR CEILINGS AFTER 22.09Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
229 AM CST MON NOV 21 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...BOYNE
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 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 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
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
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...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 WILMINGTON NC
1104 PM EST TUE NOV 22 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 /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...FAIRLY VIGOROUS FRONT WILL PASS THROUGH THE CWA TOWARD
MORNING. AHEAD OF THE FRONT...A BRIEF IFR CEILING IS
POSSIBLE...HOWEVER INSTABILITY AND DECENT MIXING WILL MAKE IT A
FAIRLY LOW PROBABILITY. STRONGEST OMEGA WILL BE JUST AHEAD OF THE
FRONT AND RACING EAST. THE HRRR MODEL HAS SOME CONVECTION WITH A
PRE-FRONTAL TROUGH MOVING RAPIDLY UP THE COAST...HOWEVER MOST OF THE
CONVECTION WILL STAY OFFSHORE. LOOK FOR GUSTY SOUTHWEST WINDS WITH
THE CONVECTION AS IT MOVES IN. VISIBILITIES AT THAT TIME WILL BE
NEAR IFR...WITH BRIEF IFR VISIBILITIES POSSIBLE IN BRIEF HEAVY RAIN.
LOOK FOR CONVECTION TO EXIT THE COAST BY 15Z. DO NOT EXPECT ANY
PRECIP BEHIND THE FRONT...AS DEEP MOISTURE STAYS EAST OF THE FRONTAL
BOUNDARY. POST FRONTAL...GRADUAL IMPROVEMENT TO VFR WITH GUSTY WEST
WINDS...BECOMING NORTHWEST. ALL TERMINALS WILL SCATTER BY LATE
MORNING.
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...HDL
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
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 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 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 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 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...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
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
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 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 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 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 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 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