SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
1118 AM PDT MON OCT 27 2008
UPDATED AVIATION SECTION
.SHORT TERM...
MARINE LAYER NOT BEHAVING VERY WELL TONIGHT AS GRADIENTS ARE
TRENDING A LITTLE MORE OFFSHORE THAN THEY WERE LAST NIGHT. THE BULK
OF THE DENSE FOG IS OVER THE CENTRAL COAST WHERE A DENSE FOG
ADVISORY IS IN EFFECT THROUGH 8 AM. ACARS SOUNDING OUT OF KLAX SHOWS
THE MARINE AT 500 FEET OR BELOW. BUT IT IS 78 DEGREES AT 1000 FEET
WHICH WILL MAKE FOR ANOTHER WARM DAY IN THE VLYS AND COASTAL INLAND
AREAS. THE COASTAL AREAS WILL REMAIN COOL. SOME HIGH CLOUDS ROTATING
AROUND AN UPPER LOW 900 NM WEST OF SFO WILL CREATE PARTLY CLOUDY
SKIES FOR SLO AND SBA COUNTIES.
DUE TO THE WARM DRY AIR ABOVE THE INVERSION A RED FLAG WARNING WILL
CONTINUE TODAY FOR EXTENDED VERY LOW CONDITIONS.
TUESDAY THE RIDGE BREAKS DOWN A LITTLE AS A TROF RIDES UP INTO
NORTHERN CA. THIS SHOULD LIFT THE MARINE LAYER ENOUGH TO GREATLY
REDUCE OR ELIMINATE THE DENSE FOG. HARD TO FIGURE WHY BUT MOS
GUIDANCE FORECASTS A 4 TO 5 DEGREE WARM UP OVER MOST AREAS DUE TO A
SPIKE IN 950 AND BL TEMPS. THINK THIS IS A LITTLE OVERDONE ESP WITH
THE GREATER MARINE LAYER AND ONSHORE FLOW.
WEDNESDAY SHOULD BE MUCH LIKE TUESDAY WITH SUNNY SKIES PREVAILING
AFTER A ROUND OF MORNING LOW CLOUDS AND FOG. THE SYNOPTIC PATTERN IS
A LITTLE MORE STATIC WITH A RIDGE SETTING UP OVER AC AND A DIGGING
TROF SETTING UP OVER THE EAST PAC.
.LONG TERM...
INTERESTING TIMES IN THE EXTENDED FORECAST BUT SOMEWHAT CHALLENGING
TO FIGURE OUT HOW INTERESTING. THE GFS AND EC AGREE FAIRLY WELL
EXCEPT IN THE CRITICAL WEEKEND PERIOD WHERE EC IS QUICKER THAN THE
SLOWER EC. ALL GFS ENSEMBLES TEND TOWARD THE OPERATIONAL GFS. BUT
18Z AND 00Z GFS HAVE TRENDED MUCH WETTER.
CONFIDENCE IN THURSDAY AND FRIDAY FORECAST LOOKS GOOD. WITH RIDGE
SLOWLY MOVING TO THE EAST AND THE TROF SLOWLY APPROACHING THE COAST
THE DAYS WILL SLOWLY COOL. THE MARINE LAYER WILL EXPAND ON THURSDAY.
SKIES WILL TURN PARTLY CLOUDY THU AFTERNOON AS MID AND HIGH LEVEL
MOISTURE EMBEDDED IN THE SW FLOW AHEAD OF THE TROF STREAMS OVER THE
AREA. THE MARINE LAYER MAY WELL BE DISRUPTED BY THE UPPER LEVEL
CLOUDS FRIDAY AND WITH ALL THE CLOUDS WORDED THE FORECAST AS PARTLY
TO MOSTLY CLOUDY WHICH WILL LIKELY WILL BEST DESCRIBE THE DAY.
SATURDAY AND SUNDAY WILL BE COOLER AS THE LOW APPROACHES. AS
MENTIONED ABOVE THE GFS IS SLOWER AND FAIRLY WET AND THE EC IS
FASTER AND DRIER. IT LOOKS MORE AND MORE LIKELY THAT THE CENTRAL
COAST WILL SEE SOME RAIN THIS WEEKEND BUT THE TIMING UNCERTAINTIES
DO NOT ALLOW ANY ONE 6 OR 12 HOUR TIME BLOCK TO HOLD HIGHER THAN
SLGT CHC POPS. SOUTH OF POINT CONCEPTION IF THE GFS FINDS ITS
SUBTROPICAL MOISTURE PLUME...AS THE GFS IS ADVERTISING...THERE WILL
BE RAIN AND MAYBE A DECENT AMOUNT. THE GFS IS SLOWER AND KEEPS ALL
THE PRECIP OUT OF THE AREA UNTIL SUNDAY. IT WILL BE INTERESTING TO
WATCH THIS SYSTEM EVOLVE.
&&
.AVIATION...27/1800Z.
UPPER LEVEL TROUGH OF LOW PRESSURE CENTERED ALONG 124W WILL SHIFT
NORTHEAST THROUGH THE PERIOD. MODERATE UPPER LEVEL SOUTH FLOW OVER
THE AREA WILL BECOME LIGHT SOUTHWEST BY THE END OF THE PERIOD. A
WEAK PRESSURE GRADIENT OVER THE AREA WILL PERSIST WITH LIGHT ONSHORE
FLOW EARLY BECOMING LIGHT OFFSHORE LATER IN THE PERIOD. THE BASE OF
THE CAPPING MARINE INVERSION WAS LESS THAN 1KFT THIS MORNING...AND
EXPECT LITTLE CHANGE OR DESCEND SLIGHTLY WHILE A LOW LEVEL RIDGE
REBUILDS THROUGH TUE MORNING. LOW CLOUD FIELD WAS LIMITED NEAR SHORE
AND WHILE A WEAK PRESSURE GRADIENT EXIST CLOUD FIELD WILL GRADUALLY
INCREASE OVER THE BIGHT.
KLAX...THERE IS A CHANCE VISIBILITY AROUND 3SM HZ WILL PERSIST
THROUGH NOON. THERE IS A CHANCE CIGS WILL RETURN LATER IN THE PERIOD
WITH VIS ABOVE 1/2SM FG THROUGH 11Z.
KBUR...VIRTUALLY CERTAIN CLEAR SKIES BELOW 12KFT WILL PREVAIL.
VIRTUALLY CERTAIN - 95-100%
VERY LIKELY - 80-95%
LIKELY - 60-80%
CHANCE - 30-60%
VERY UNLIKELY - 20% OR LESS
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING (SEE LAXRFWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...RORKE
AVIATION...30
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
1115 AM PDT MON OCT 27 2008
UPDATED AVIATION SECTION
.SHORT TERM...
MARINE LAYER NOT BEHAVING VERY WELL TONIGHT AS GRADIENTS ARE
TRENDING A LITTLE MORE OFFSHORE THAN THEY WERE LAST NIGHT. THE BULK
OF THE DENSE FOG IS OVER THE CENTRAL COAST WHERE A DENSE FOG
ADVISORY IS IN EFFECT THROUGH 8 AM. ACARS SOUNDING OUT OF KLAX SHOWS
THE MARINE AT 500 FEET OR BELOW. BUT IT IS 78 DEGREES AT 1000 FEET
WHICH WILL MAKE FOR ANOTHER WARM DAY IN THE VLYS AND COASTAL INLAND
AREAS. THE COASTAL AREAS WILL REMAIN COOL. SOME HIGH CLOUDS ROTATING
AROUND AN UPPER LOW 900 NM WEST OF SFO WILL CREATE PARTLY CLOUDY
SKIES FOR SLO AND SBA COUNTIES.
DUE TO THE WARM DRY AIR ABOVE THE INVERSION A RED FLAG WARNING WILL
CONTINUE TODAY FOR EXTENDED VERY LOW CONDITIONS.
TUESDAY THE RIDGE BREAKS DOWN A LITTLE AS A TROF RIDES UP INTO
NORTHERN CA. THIS SHOULD LIFT THE MARINE LAYER ENOUGH TO GREATLY
REDUCE OR ELIMINATE THE DENSE FOG. HARD TO FIGURE WHY BUT MOS
GUIDANCE FORECASTS A 4 TO 5 DEGREE WARM UP OVER MOST AREAS DUE TO A
SPIKE IN 950 AND BL TEMPS. THINK THIS IS A LITTLE OVERDONE ESP WITH
THE GREATER MARINE LAYER AND ONSHORE FLOW.
WEDNESDAY SHOULD BE MUCH LIKE TUESDAY WITH SUNNY SKIES PREVAILING
AFTER A ROUND OF MORNING LOW CLOUDS AND FOG. THE SYNOPTIC PATTERN IS
A LITTLE MORE STATIC WITH A RIDGE SETTING UP OVER AC AND A DIGGING
TROF SETTING UP OVER THE EAST PAC.
.LONG TERM...
INTERESTING TIMES IN THE EXTENDED FORECAST BUT SOMEWHAT CHALLENGING
TO FIGURE OUT HOW INTERESTING. THE GFS AND EC AGREE FAIRLY WELL
EXCEPT IN THE CRITICAL WEEKEND PERIOD WHERE EC IS QUICKER THAN THE
SLOWER EC. ALL GFS ENSEMBLES TEND TOWARD THE OPERATIONAL GFS. BUT
18Z AND 00Z GFS HAVE TRENDED MUCH WETTER.
CONFIDENCE IN THURSDAY AND FRIDAY FORECAST LOOKS GOOD. WITH RIDGE
SLOWLY MOVING TO THE EAST AND THE TROF SLOWLY APPROACHING THE COAST
THE DAYS WILL SLOWLY COOL. THE MARINE LAYER WILL EXPAND ON THURSDAY.
SKIES WILL TURN PARTLY CLOUDY THU AFTERNOON AS MID AND HIGH LEVEL
MOISTURE EMBEDDED IN THE SW FLOW AHEAD OF THE TROF STREAMS OVER THE
AREA. THE MARINE LAYER MAY WELL BE DISRUPTED BY THE UPPER LEVEL
CLOUDS FRIDAY AND WITH ALL THE CLOUDS WORDED THE FORECAST AS PARTLY
TO MOSTLY CLOUDY WHICH WILL LIKELY WILL BEST DESCRIBE THE DAY.
SATURDAY AND SUNDAY WILL BE COOLER AS THE LOW APPROACHES. AS
MENTIONED ABOVE THE GFS IS SLOWER AND FAIRLY WET AND THE EC IS
FASTER AND DRIER. IT LOOKS MORE AND MORE LIKELY THAT THE CENTRAL
COAST WILL SEE SOME RAIN THIS WEEKEND BUT THE TIMING UNCERTAINTIES
DO NOT ALLOW ANY ONE 6 OR 12 HOUR TIME BLOCK TO HOLD HIGHER THAN
SLGT CHC POPS. SOUTH OF POINT CONCEPTION IF THE GFS FINDS ITS
SUBTROPICAL MOISTURE PLUME...AS THE GFS IS ADVERTISING...THERE WILL
BE RAIN AND MAYBE A DECENT AMOUNT. THE GFS IS SLOWER AND KEEPS ALL
THE PRECIP OUT OF THE AREA UNTIL SUNDAY. IT WILL BE INTERESTING TO
WATCH THIS SYSTEM EVOLVE.
&&
.AVIATION...27/1800Z.
UPPER LEVEL TROUGH OF LOW PRESSURE CENTERED ALONG 124W WILL SHIFT
NORTHEAST THROUGH THE PERIOD. MODERATE UPPER LEVEL SOUTH FLOW OVER
THE AREA WILL BECOME LIGHT SOUTHWEST BY THE END OF THE PERIOD. A
WEAK PRESSURE GRADIENT OVER THE AREA WILL PERSIST WITH LIGHT ONSHORE
FLOW EARLY BECOMING LIGHT OFFSHORE LATER IN THE PERIOD. THE BASE OF
THE CAPPING MARINE INVERSION WAS AROUND 1KFT THIS MORNING...AND
EXPECT LITTLE CHANGE OR DESCEND SLIGHTLY WHILE A LOW LEVEL RIDGE
REBUILDS THROUGH TUE MORNING. LOW CLOUD FIELD WAS LIMITED NEAR SHORE
AND WHILE A WEAK PRESSURE GRADIENT EXIST CLOUD FIELD WILL GRADUALLY
INCREASE OVER THE BIGHT.
KLAX...THERE IS A CHANCE VISIBILITY AROUND 3SM HZ WILL PERSIST
THROUGH NOON. THERE IS A CHANCE CIGS WILL RETURN LATER IN THE PERIOD
WITH VIS ABOVE 1/2SM FG THROUGH 11Z.
KBUR...VIRTUALLY CERTAIN CLEAR SKIES BELOW 12KFT WILL PREVAIL.
VIRTUALLY CERTAIN - 95-100%
VERY LIKELY - 80-95%
LIKELY - 60-80%
CHANCE - 30-60%
VERY UNLIKELY - 20% OR LESS
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING (SEE LAXRFWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...RORKE
AVIATION...30
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION...UPDATE
NWS MARQUETTE MI
730 PM EDT MON OCT 27 2008
.UPDATE...
REDUCED POPS/QPF/FCST SN AMTS A BIT OVERNGT WITH LLVL DRY AIR SHOWN
UPSTREAM (SFC DWPT DEPRESSIONS APRCHG 15F IN SOME PLACES/RECENT
TAMDAR SDNGS FM HIB/YQT)...TENDENCY OVERNGT FOR LLVL FLOW TO BCM
MORE ACYC THRU THE NGT UNDER RISING HGTS...AND POOR SN GROWTH
MICROPHYSICS WITH SINKING/STRENGTHENING INVRN CUTTING OFF THE MOIST
LYR FM THE -10C ISOTHERM. ALSO MENTIONED A MIX WITH RA NEAR LK SUP
OVER THE E EARLY THIS EVNG WITH 23Z SFC TEMP STILL 42 AT P53.
&&
.SHORT TERM...
LES ACROSS THE WESTERN ZONES APPEARS TO BE WINDING
DOWN. UPSTREAM TAMDAR SOUNDINGS (CYQT...KINL) INDICATE DRIER AIR HAS
BEGUN TO WORK IN AS INDICATED BY SHALLOW MOISTURE PRESENT BTWN
3-5KFT. LATEST LOCAL HI-RES/12ZNAM ALSO SUPPORT THIS INTRUSION OF
DRIER AIR PER LOW-LVL RH/CONVERGENCE FIELDS. THIS ALONG FALLING
INVERSION HEIGHTS SUPPORTED EARLY END TO WW ADVISORY. EXPECT SOME
LIGHT LES TO LINGER THROUGHOUT THE NIGHT...THOUGH AMOUNTS WILL BE
LIGHT. DIFFERENT STORY FOR AREAS OF THE EASTERN CWA...NAMELY
PORTIONS OF ALGER....SCHOOLCRAFT AND LUCE COUNTIES (TYPICAL NW LES
BELTS). AMPLE MOISTURE AND LOW LEVEL CONVERGENCE WILL ALLOW
MULTI-BAND LES TO CONTINUE...IN SOME FORM...THROUGH TOMORROW NIGHT.
DON/T EXPECT AMOUNTS TO GET OUT OF HAND DESPITE PERSISTENT MULTI LES
BAND. CURRENT EASTERN LES BANDS APPEAR TO BE ENHANCED AT LEAST
MARGINALLY BY MOISTURE FROM LAKE NIPIGON. LATEST VIS SATELLITE
ACTUALLY SHOWS SOME MOISTURE CONNECTION EXTENDING INTO NORTHWESTERN
LOWER MICHIGAN ALSO. LOCAL HI-RES WRF-ARW MODEL INDICATES DOMINANT
BAND EXTENDING FROM FROM LAKE NIPIGON ALL THE WAY TO LOWER MICHIGAN
BY 08Z TONIGHT. IF THE GROUND TEMPS WERE COOLER THIS COULD PRESENT A
GOOD ACCUMULATION POTENTIAL...HOWEVER...EXPECTING LITTLE
ACCUMULATION (1 TO 2 INCHES) THROUGH TOMORROW DUE TO RELATIVELY WARM
GROUND TEMPERATURES. ADDED IN HIGHER POPS/QPF INTO LUCE COUNTY AS
SLIGHT BACKING OF WINDS TOMORROW AFTERNOON SHOULD SHIFT BANDS
FURTHER EAST. ABUNDANT CLOUD COVER OVERNIGHT WON/T ALLOW TEMPS TO
COOL MUCH...MID 20S WEST TO AROUND 30 EAST.
.LONG TERM (TUE NIGHT THROUGH NEXT MON)...
SHORTWAVE OVR SOUTHERN NUNAVUT DIGS INTO NE CONUS TROUGH ON TUE
NIGHT. ALTHOUGH MAIN AREA OF PVA WITH THE WAVE STAYS TO THE EAST OF
CWA AS SHORTWAVE TRACKS OVR FAR ERN LAKE SUPERIOR...EXPECT AN
INCREASE IN DEEP MOISTURE. YET...SOUNDINGS INDICATE ONLY MINIMAL
POSITIVE RESPONSE IN LOW LEVEL OMEGA. KEPT A CORRIDOR OF HIGH CHANCE
POPS BTWN MQT AND ERY WHERE GREATEST 925MB CONVERGENCE IS PRESENT ON
NAM/LOCAL WRF. INCREASING NVA AND DIMINSHING MOISTURE ABOVE 4KFT AFT
06Z WILL DIMINISH ANY STRONGER SHSN. DECREASING TREND IN LK EFFECT
REALLY DEVELOPS BY MID MORNING WED WITH ARRIVAL OF 925-850MB RIDGE
AND DRY AIR IN THIS LAYER. TEMPS IN THIS LAYER REMAIN BLO -5C
THROUGH 18Z...BUT AT THE WORST...ONLY EXPECT STRATOCU CLOUDS TO
LINGER BLO LOWERING INVERSION. SFC RIDGE/DRY WX BUILDS FM NORTHERN
PLAINS INTO UPR LAKES WED/WED NIGHT. MAIN ISSUE FOR THU IS TEMPS. SW
FLOW ALOFT AND AT THE SFC ALLOWS 925MB TEMPS TO INCREASE TO +8C AND
H85 TEMPS TO POP UP ABOVE +10C. SOUNDINGS INDICATE MIXING HEIGHTS TO
900MB...SO EXPECT TEMPS INTO THE UPR 50S/LWR 60S. RECORDS FOR 30 OCT
ACROSS THE CWA ARE IN THE UPR 60S TO MID 70S SO TEMPS PUSHING ABOVE
60 ARE DEFINITELY NOT UNHEARD OF BUT ARE QUITE A CHANGE COMPARED TO
THE CHILLY READINGS TO START THIS WEEK.
DAYS 4-7...BULK OF LONGWAVE TROUGH EXITS EASTERN CANADA BY THIS TIME
BUT ADDITIONAL TROUGHING DEVELOPS OVR ERN CANADA. ECMWF PREFERRED BY
HPC FOR THIS TIME FRAME INDICATES THE TROUGH SLIDES INTO NEW ENGLAND
AND RIDGING BUILDS FM THE PLAINS INTO THE UPR GREAT LAKES. BEFORE
THIS WARMING OCCURS...ONE MORE COLD FRONT IS DUE IN HALLOWEEN DAY.
TIMING WITH THE FRONT HAS BEEN PRETTY CONSISTENT OVR LAST FEW DAYS.
GIVEN THE POTENTIAL FOR FALLING TEMPS BUT WARMER TEMPS TO START THE
DAY WENT AHEAD AND INCLUDED BOTH RA/SN IN WX GRIDS. LARGE AREA OF
HIGH PRESSURE WITH A WEALTH OF DRY AIR THEN BUILDS ACROSS FOR SAT
QUICKLY ENDING ANY PCPN FOR THE WEEKEND. RETURN FLOW THEN DEVELOPS
BY SUN BTWN THE DEPARTING HIGH AND AN APPROACHING LOW PRESSURE
SYSTEM IN THE NORTHERN PLAINS. GFS/ECMWF SHOW SOME QPF NOW FOR NEXT
MON...BUT SINCE THAT IS A CHANGE FM PREVIOUS MODEL RUNS...HELD ON TO
A DRY FORECAST WITH EXPECTATION THAT BEST FORCING FOR PCPN REMAINS
WEST AND NORTH OF UPR LAKES.
&&
.AVIATION (FOR THE 00Z TAF ISSUANCE)...
INFLUX OF DRIER AIR FM THE NW PER RECENT TAMDAR SDNG FM HIB/HI SFC
DWPT DEPRESSIONS AND SUBSIDENCE/INCRSGLY ACYC LLVL FLOW WL STUNT LK
EFFECT SHSN INTO TUE...WITH VFR VSBY. CIGS WITHIN THE SC UPSTREAM
ARE GENERALLY VFR. ALTHOUGH AN MVFR DECK IS PSBL AT TIMES ESPECIALLY
AT CMX PER A FEW UPSTREAM OBS...VFR CIGS SHOULD PREDOMINATE AT BOTH
SITES. SOME -SHSN AND GUSTY WINDS WL DVLP TMRW AFTN WITH APRCH OF
SHRTWV FM THE NW.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
GALES HAVE ENDED BUT SOMEWHAT TIGHT PRESSURE GRADIENT REMAINS IN
PLACE. EXPECT WINDS TO DIMINISH TO 25 KNOTS LATER TONIGHT THEN
INCREASE BACK TO 30 KNOTS TUE NIGHT INTO WED MORNING AS REINFORCING
SHOT OF COLD AIR PUSHES OVER FAR ERN LK SUPERIOR. ARRIVAL OF HIGH
PRES RIDGE LEADS TO DIMINISHING WINDS BY WED NIGHT...THEN RETURN
FLOW DEVELOPING THU INTO FRI RESULTS IN SW WINDS INCREASING TO 25
KNOTS. A COLD FRONT DROPPING ACROSS THE REGION ON FRI WILL SWITCH
WINDS BACK TO NRLY BY FRI NIGHT WITH WINDS UP TO 30 KNOTS INTO SAT.
NO GALES ARE FORSEEN THROUGH LATE THIS WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
UPDATE...KC
SYNOPSIS/SHORT TERM...PEARSON
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
400 PM EDT MON OCT 27 2008
.SHORT TERM...
LES ACROSS THE WESTERN ZONES APPEARS TO BE WINDING
DOWN. UPSTREAM TAMDAR SOUNDINGS (CYQT...KINL) INDICATE DRIER AIR HAS
BEGUN TO WORK IN AS INDICATED BY SHALLOW MOISTURE PRESENT BTWN
3-5KFT. LATEST LOCAL HI-RES/12ZNAM ALSO SUPPORT THIS INTRUSION OF
DRIER AIR PER LOW-LVL RH/CONVERGENCE FIELDS. THIS ALONG FALLING
INVERSION HEIGHTS SUPPORTED EARLY END TO WW ADVISORY. EXPECT SOME
LIGHT LES TO LINGER THROUGHOUT THE NIGHT...THOUGH AMOUNTS WILL BE
LIGHT. DIFFERENT STORY FOR AREAS OF THE EASTERN CWA...NAMELY
PORTIONS OF ALGER....SCHOOLCRAFT AND LUCE COUNTIES (TYPICAL NW LES
BELTS). AMPLE MOISTURE AND LOW LEVEL CONVERGENCE WILL ALLOW
MULTI-BAND LES TO CONTINUE...IN SOME FORM...THROUGH TOMORROW NIGHT.
DON/T EXPECT AMOUNTS TO GET OUT OF HAND DESPITE PERSISTENT MULTI LES
BAND. CURRENT EASTERN LES BANDS APPEAR TO BE ENHANCED AT LEAST
MARGINALLY BY MOISTURE FROM LAKE NIPIGON. LATEST VIS SATELLITE
ACTUALLY SHOWS SOME MOISTURE CONNECTION EXTENDING INTO NORTHWESTERN
LOWER MICHIGAN ALSO. LOCAL HI-RES WRF-ARW MODEL INDICATES DOMINANT
BAND EXTENDING FROM FROM LAKE NIPIGON ALL THE WAY TO LOWER MICHIGAN
BY 08Z TONIGHT. IF THE GROUND TEMPS WERE COOLER THIS COULD PRESENT A
GOOD ACCUMULATION POTENTIAL...HOWEVER...EXPECTING LITTLE
ACCUMULATION (1 TO 2 INCHES) THROUGH TOMORROW DUE TO RELATIVELY WARM
GROUND TEMPERATURES. ADDED IN HIGHER POPS/QPF INTO LUCE COUNTY AS
SLIGHT BACKING OF WINDS TOMORROW AFTERNOON SHOULD SHIFT BANDS
FURTHER EAST. ABUNDANT CLOUD COVER OVERNIGHT WON/T ALLOW TEMPS TO
COOL MUCH...MID 20S WEST TO AROUND 30 EAST.
.LONG TERM (TUE NIGHT THROUGH NEXT MON)...
SHORTWAVE OVR SOUTHERN NUNAVUT DIGS INTO NE CONUS TROUGH ON TUE NIGHT.
ALTHOUGH MAIN AREA OF PVA WITH THE WAVE STAYS TO THE EAST OF CWA AS
SHORTWAVE TRACKS OVR FAR ERN LAKE SUPERIOR...EXPECT AN INCREASE IN
DEEP MOISTURE. YET...SOUNDINGS INDICATE ONLY MINIMAL POSITIVE
RESPONSE IN LOW LEVEL OMEGA. KEPT A CORRIDOR OF HIGH CHANCE POPS
BTWN MQT AND ERY WHERE GREATEST 925MB CONVERGENCE IS PRESENT ON
NAM/LOCAL WRF. INCREASING NVA AND DIMINSHING MOISTURE ABOVE 4KFT AFT
06Z WILL DIMINISH ANY STRONGER SHSN. DECREASING TREND IN LK EFFECT
REALLY DEVELOPS BY MID MORNING WED WITH ARRIVAL OF 925-850MB RIDGE
AND DRY AIR IN THIS LAYER. TEMPS IN THIS LAYER REMAIN BLO -5C
THROUGH 18Z...BUT AT THE WORST...ONLY EXPECT STRATOCU CLOUDS TO
LINGER BLO LOWERING INVERSION. SFC RIDGE/DRY WX BUILDS FM NORTHERN
PLAINS INTO UPR LAKES WED/WED NIGHT. MAIN ISSUE FOR THU IS TEMPS. SW
FLOW ALOFT AND AT THE SFC ALLOWS 925MB TEMPS TO INCREASE TO +8C AND
H85 TEMPS TO POP UP ABOVE +10C. SOUNDINGS INDICATE MIXING HEIGHTS TO
900MB...SO EXPECT TEMPS INTO THE UPR 50S/LWR 60S. RECORDS FOR 30 OCT
ACROSS THE CWA ARE IN THE UPR 60S TO MID 70S SO TEMPS PUSHING ABOVE
60 ARE DEFINITELY NOT UNHEARD OF BUT ARE QUITE A CHANGE COMPARED TO
THE CHILLY READINGS TO START THIS WEEK.
DAYS 4-7...BULK OF LONGWAVE TROUGH EXITS EASTERN CANADA BY THIS TIME
BUT ADDITIONAL TROUGHING DEVELOPS OVR ERN CANADA. ECMWF PREFERRED BY
HPC FOR THIS TIME FRAME INDICATES THE TROUGH SLIDES INTO NEW ENGLAND
AND RIDGING BUILDS FM THE PLAINS INTO THE UPR GREAT LAKES. BEFORE
THIS WARMING OCCURS...ONE MORE COLD FRONT IS DUE IN HALLOWEEN DAY.
TIMING WITH THE FRONT HAS BEEN PRETTY CONSISTENT OVR LAST FEW DAYS.
GIVEN THE POTENTIAL FOR FALLING TEMPS BUT WARMER TEMPS TO START THE
DAY WENT AHEAD AND INCLUDED BOTH RA/SN IN WX GRIDS. LARGE AREA OF
HIGH PRESSURE WITH A WEALTH OF DRY AIR THEN BUILDS ACROSS FOR SAT
QUICKLY ENDING ANY PCPN FOR THE WEEKEND. RETURN FLOW THEN DEVELOPS
BY SUN BTWN THE DEPARTING HIGH AND AN APPROACHING LOW PRESSURE
SYSTEM IN THE NORTHERN PLAINS. GFS/ECMWF SHOW SOME QPF NOW FOR NEXT
MON...BUT SINCE THAT IS A CHANGE FM PREVIOUS MODEL RUNS...HELD ON TO
A DRY FORECAST WITH EXPECTATION THAT BEST FORCING FOR PCPN REMAINS
WEST AND NORTH OF UPR LAKES.
&&
.AVIATION (FOR THE 18Z TAF ISSUANCE)...
GUSTY WINDS FROM THIS MORNING ARE SUBSIDING AT THIS TIME...THOUGH
GUSTS TO 25 KNOTS WILL BE COMMON THROUGH 00Z. EXPECT DIMINISHING
LAKE EFFECT SNOW TRENDS AT CMX AND SAW...THOUGH WOULDN/T BE
SURPRISED TO SEE TEMPORARY MVFR CLOUD DECKS WITH OFF AND ON SNOW
SHOWERS. WITH THIS IN MIND...VFR CONDITIONS GENERALLY EXPECTED AT
BOTH TAF SITES THROUGH TAF PERIOD.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
GALES HAVE ENDED BUT SOMEWHAT TIGHT PRESSURE GRADIENT REMAINS IN
PLACE. EXPECT WINDS TO DIMINISH TO 25 KNOTS LATER TONIGHT THEN
INCREASE BACK TO 30 KNOTS TUE NIGHT INTO WED MORNING AS REINFORCING
SHOT OF COLD AIR PUSHES OVER FAR ERN LK SUPERIOR. ARRIVAL OF HIGH
PRES RIDGE LEADS TO DIMINISHING WINDS BY WED NIGHT...THEN RETURN
FLOW DEVELOPING THU INTO FRI RESULTS IN SW WINDS INCREASING TO 25
KNOTS. A COLD FRONT DROPPING ACROSS THE REGION ON FRI WILL SWITCH
WINDS BACK TO NRLY BY FRI NIGHT WITH WINDS UP TO 30 KNOTS INTO SAT.
NO GALES ARE FORSEEN THROUGH LATE THIS WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON
FOR MIZ002-004-009-084.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
SYNOPSIS/SHORT TERM...PEARSON
LONG TERM...JLA
AVIATION...PEARSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
634 AM CDT SUN OCT 26 2008
.DISCUSSION...
THE BIG STORY WEATHER WISE IS THE WIND EVENT FOR TODAY. DECIDED
TO ISSUE A HIGH WIND WARNING FOR MOST OF THE AREA UNDER A WATCH
AND CONTINUED WITH WIND ADVISORY REMAINDER OF CWA. JUST PUSHED
BACK START TIME ON HEADLINES A COUPLE OF HOURS TO BEGIN AT 0900.
VAD WIND PROFILERS AT BIS/ABR/FSD ALL SHOWING AROUND 70 KTS OF
WIND JUST A COUPLE OF THOUSAND FEET OFF GROUND. DEEP LAYER OF
STRONG WINDS AVAILABLE TO MIX DOWN TODAY WITH PROGGED SOUNDINGS
OFF NAM/GFS SHOWING NEAR ADIABATIC LAPSE RATES DEVELOPING TO
AROUND 700 MB. CONFINED TO WARNING TO OUR NORMAL HIGH WIND AREAS
IN WC INTO SC MN. IN THAT AREA GFS90 IS SHOWING 1000-850 MB LAPSE
RATES OVER 8C/KM DEVELOPING THIS MORNING AND INTO THE
AFTERNOON...THIS BEING THE AREA WITH BEST OPPORTUNITY FOR SOME
SUN. SOME CONCERN THAT ANY VIRGA/SHOWERS IN CWA MAY ALSO DRIVE
STRONG GUSTS TO THE GROUND AS WAS THE CASE THE PAST EVENING IN
SODAK AS SOUNDINGS DO SHOW INVERTED V CHARACTERISTICS. MAY ALSO
SEE SOME INCREASE IN WINDS THIS AFTERNOON IN SUBSIDENCE IN THE WAKE
OF RATHER STRONG VORT NOW DROPPING OUT OF SASK TOWARD NODAK WHICH
WILL CROSS CWA EARLY AFTERNOON. HAVE EXPIRATION TIME OF 00Z FOR
THE WARNING...WHICH WILL LIKELY HAVE TO BE EXTENDED AS A WIND
ADVISORY FOR THE EVENING.
COLD ADVECTION NOT COMING THRU IN ONE PUNCH WITH TEMPERATURES
STILL IN THE 40S ACROSS MOST OF MN INTO THE EASTERN DAKOTAS. UPPED
MAX TEMPERATURES A COUPLE OF DEGREES TO ACCOUNT FOR A MILD
START...BUT CONTINUED COLD ADVECTION WILL TREND TEMPERATURES
DOWNWARD THRU DAY. TRENDED POPS MORE TOWARD THE GFS THAN THE DRIER
NAM FOR TODAY AS FAIRLY STRONG LIFT AHEAD OF SASK VORT. EXPECT
MEASURABLE TO BE CONFINED TO NE 1/2 AREA. PRECIP WILL START AS
-RW...BUT BY 18Z SHOULD BE MAINLY -SW AS LOW LEVELS COOL WITH
RUC/GFS/NAM SHOWING FREEZING LEVEL DROPPING TO BLO 1K AGL.
1000-850 MB RH REMAINS HIGH TONIGHT INTO MONDAY ESPECIALLY IN WI
AND E MN IN COLD CYCLONIC FLOW. EXPECT PERIODS OF -SW WITH MAYBE A
DUSTING IN WI. CONTINUED COLD MONDAY BUT WARMING TREND BEGINNING
TUESDAY AS UPSTREAM RIDGE BEGINS TO FLATTEN. TEMPS BY WEDNESDAY
INTO FRIDAY EXPECTED TO BE ABOVE NORMAL WITH MILD PACIFIC FLOW.
UPPED TEMPERATURES SEVERAL DEGREES WEDNESDAY INTO FRIDAY.
&&
.AVIATION.../12Z TAF ISSUANCE/
WEST NORTHWEST WINDS INCREASING IN SPEED ACROSS THE AREA AND WILL
DO SO QUITE RAPIDLY THROUGH MID TO LATE MORNING AS BETTER SYNOPTIC
ELEMENTS MOVE ATOP THE AREA. BETWEEN 10Z AND 12Z IN THE ERN
DAKOTAS...SOME WIND GUSTS IN EXCESS OF 45 KTS HAVE BEEN OBSERVED.
THIS IS EXPECTED TO TRANSLATE OVER AT LEAST RWF TODAY AND QUITE
POSSIBLY OTHER MN TAF SITES AT TIMES. THE UNIDIRECTIONAL WIND
COLUMN IN THE ATMOSPHERE WITH STEEPENING LAPSE RATES FAVORS GUSTS
WELL ABOVE THE SUSTAINED SPEEDS...AND HAVE GENERALLY CONTINUED
THAT APPROACH IN THE TAFS. 1102Z TAMDAR FLIGHT INTO MSP ALREADY
SHOWED A DRY-ADIABATIC LAPSE RATE TO 3000 FT. AND DOPPLER WIND
PROFILERS FROM AREA RADARS INDICATE VERY STRONG WINDS IN THE 2-3
KFT LAYER. SOME WIND SHEAR TOO CAN BE EXPECTED AT TAF SITES WITH
THESE WINDS...BUT BELOW THE MENTIONABLE CRITERIA GIVEN THE
STRENGTH OF THE SFC WINDS. STILL INCREASE IN SPEED WILL BE
SOMEWHAT RAPID AS ASCENDING 12Z RAOB HERE AT MPX HAD A 34 KT
INCREASE BETWEEN SFC AND 1 KFT AGL. THE WINDS SHOULD DECREASE
GRADUALLY DURING THE LATER AFTN INTO THE EVE AS BEST DEEP LAYER
FORCING FOR WINDS EVOLVE AWAY.
SHOWERS ACROSS THE NRN HALF OF MN SHOULD SLOWLY TRANSITION ESE
INTO TODAY AS ONE SHORT WAVE IMPULSE MOVES ACROSS CTRL MN. FORCING
SHOULD APPROACH AXN...STC AND WI TAF SITES DURING THE MID TO LATE
MORNING. PRECIP TYPE TRANSITIONING TO SNOW RAPIDLY IN NW MN AS
THICKNESSES SIGNIFICANTLY LOWER. BETTER CHANCE FOR SHOWER COVERAGE
WILL COME LATER IN THE AFTN AND THIS EVE IN ERN MN AND WRN WI AS
PVA RE-INCREASES AHEAD OF PARENT VORT. PRECIP TYPE BY THIS TIME
LOOKS HIGHLY LIKELY TO BE SNOW SHOWERS. GIVEN THE WINDS AND THIS
PRECIP TYPE THERE COULD BE SOME VERY REDUCED VISIBILITIES IF THE
SHOWERS HAVE GOOD COVERAGE. HAVE ONLY GONE MVFR AT THIS TIME BUT
WILL NEED TO WATCH. HAVE ALSO TRENDED SLOW ON PULLING OUT MVFR
CIGS FROM ERN MN AND WRN WI AS CLIMATOLOGICAL PATTERN WOULD NOT
FAVOR A QUICK DEPARTURE OF THE CLOUD DESPITE GUIDANCE SUGGESTIONS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 1 AM CDT MONDAY FOR ANOKA-BENTON-CARVER-
CHISAGO-DAKOTA-DOUGLAS-GOODHUE-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LE SUEUR-MCLEOD-MEEKER-MILLE LACS-MORRISON-POPE-
RAMSEY-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-TODD-WASHINGTON-
WRIGHT.
HIGH WIND WARNING UNTIL 7 PM CDT THIS EVENING FOR BLUE EARTH-
BROWN-CHIPPEWA-FARIBAULT-FREEBORN-LAC QUI PARLE-MARTIN-
NICOLLET-REDWOOD-RENVILLE-STEELE-STEVENS-SWIFT-WASECA-
WATONWAN-YELLOW MEDICINE.
WI...WIND ADVISORY UNTIL 1 AM CDT MONDAY FOR BARRON-CHIPPEWA-DUNN-EAU
CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
BAP/MTF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
842 PM EDT MON OCT 27 2008
.SYNOPSIS...
A BRISK AND CHILLY AIR MASS WILL CONTINUE TO BUILD INTO THE REGION
THROUGH WEDNESDAY... BRINGING MUCH BELOW NORMAL TEMPERATURES. A
GRADUAL WARMING TREND BACK TOWARD SEASONAL NORMALS WILL FOLLOW
STARTING THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 PM MONDAY...
INTERESTING DAY ON THE NEAR TERM DESK.
LATEST SFC ANALYSIS AT 18Z PLACES THE COLD FRONT IN THE COASTAL
PLAIN OF NC FROM KASJ TO KRWI TO KFAY TO KLBT. AHEAD OF THE FRONT
TEMPS WARMED INTO THE MID 60S ACROSS THE EASTERN SANDHILLS AND
PORTIONS OF THE SOUTHERN AND CENTRAL COASTAL PLAIN WITH TEMPS
REACHING 72 AT KEDE AND 70 AT KPGV. SFC FLOW HAS BECOME NW ACROSS
THE RAH CWA AND COLD/DRY ADVECTION IS UNDERWAY. LATEST 1755Z AMDAR
SOUNDING AT KRDU SHOWS THE SFC BASED COOLING IS STILL FAIRLY SHALLOW
AND EXTENDS ONLY UP TO AROUND 2K FEET.
MAIN FEATURE OF INTEREST THIS AFTERNOON HAS BEEN A DEVELOPING BAND
OF CLOUDS AND LIGHT PRECIP ACROSS VA AND NORTHERN NC. WV IMAGERY
DEPICTS A ROBUST SHORT WAVE MOVING ACROSS THE BLUE RIDGE OF NW VA
WITH A BAROCLINIC LEAF PATTERN NOTED EARLIER ON RADAR AND SAT
IMAGERY. SHORT TERM NWP GUIDANCE SUGGESTS THAT THIS AREA OF PRECIP
WILL LIKELY EXPAND SE LATER THIS AFTN AND EVE. LOW/MID LEVEL
FRONTOGENESIS COUPLED WITH UPPER LEVEL FORCING ASSOCIATED WITH THE
UPPER LEVEL TROF AND UPPER DIVERGENCE IN THE LEFT EXIT REGION OF AN
INTENSIFYING H25 140 KT JET IS PRODUCING A DEEP LAYER OF OMEGA.
SHALLOW NATURE OF MOISTURE SHOULD LIMIT THE AMOUNT OF PRECIP BUT
FEEL THAT THE IMPRESSIVE LIFT SHOULD BE ABLE TO SQUEEZE A FEW
SHOWERS OR SPRINKLES OUT THIS EVENING...ESPECIALLY ACROSS THE N AND
CENTRAL COASTAL PLAIN. HAD SEVERAL REPORTS OF SLEET IN THE TRIAD
AREA PASSED ALONG FROM A TRIAD TV MET. SLEET WAS REPORTED BETWEEN
1245 AND 145 PM...AS PRECIPITATION DROPS FELL INTO THE DRY AIRMASS
IT BEGAN TO EVAPORATE AND COOL. THE WET BULB FREEZING LEVELS WERE IN
THE 2 TO 3K FT LEVEL ALLOWING SOME PELLETS TO FORM.
THE UPPER TROUGH AXIS SWINGS THROUGH THE CAROLINAS AND VIRGINIAS
OVERNIGHT ALLOWING SKIES TO CLEAR SOMEWHAT. COLD ADVECTION WILL
CONTINUE TONIGHT WITH THE MAIN THRUST COMING THIS EVENING. THICKNESS
VALUES DROP INTO THE 1300-1305 M RANGE BY TUE MORNING. STATISTICAL
GUIDANCE IN FAIRLY GOOD AGREEMENT WITH LOWS IN THE 33 TO 37 RANGE.
AIRMASS SHOULD REMAIN MIXED AND SCT TO BKN CLOUD COVER SHOULD
PREVENT RADIATIONAL COOLING AND FROST FORMATION. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
AS OF 305 PM MONDAY...
FOR TUESDAY: THE MID LEVEL VORTEX IS EXPECTED TO BE OVER THE
DELMARVA PENINSULA BY TUESDAY MORNING. CENTRAL NC GETS IN THE HEART
OF THE MID LEVEL THERMAL TROUGH WITH 500 MB TEMPS DROPPING TO -30C
TO -32C. FORECAST SOUNDINGS ARE RATHER UNSTABLE WITH TOTAL TOTALS
REACHING 50-54... 1000-850 MB LAPSE RATES OVER 9.5 C/KM... AND
850-500 MB LAPSE RATES OVER 7 C/KM. SCATTERED CONVECTIVE CLOUDINESS
IS EXPECTED TO DEVELOP AND JUST A FEW HUNDRED JOULES/KG OF CAPE
COULD BE ENOUGH FOR PATCHY SPRINKLES... BUT WITH SUCH A LOW
PRECIPITABLE WATER (JUST AROUND A THIRD OF AN INCH) AND DRY SURFACE
BASED LAYER... WILL REFRAIN FROM INCLUDING ANY PRECIP CHANCES AT
THIS TIME. OF POSSIBLY GREATER CONCERN WILL BE THE WINDS TOMORROW...
AS FORECAST SOUNDINGS SHOW A VERY DEEP MIXED LAYER UP TO 750-700 MB
MB WITH BOUNDARY LAYER WINDS INCREASING TO 15-20 KTS AND WINDS AT
THE TOP OF THE MIXED LAYER AROUND 30-32 KTS. STRONG SUBSIDENCE IS
LIKELY TO BRING THESE WINDS DOWN TO THE SURFACE AS EARLY AS TUESDAY
MORNING... AND WE EXPECT SUSTAINED WINDS OVER 15 MPH WITH GUSTS OF
30-35 KTS POSSIBLE. FORTUNATELY THE PROBABILITY OF LOCALLY STRONGER
WINDS SEEMS TO HAVE DIMINISHED AS THE POTENTIAL FOR AN INTRUSION OF
STRATOSPHERIC AIR TUESDAY NOW APPEARS LESS LIKELY THAN IT ONCE DID.
SINCE THE 130-140 KT UPPER JET CORE SHOULD BE WELL TO OUR
SOUTHEAST... THE ASSOCIATED TROPOPAUSE FOLD AND ANY
GROUNDWARD-DIRECTED HIGH POTENTIAL VORTICITY SHOULD LIKEWISE BE TO
OUR SOUTH. TUESDAY SHOULD EASILY BE THE COLDEST DAY IN THIS
STRETCH... AND THE MODELS HAVE BEEN CONSISTENT SHOWING LOW LEVEL
THICKNESSES NEARLY 50 METERS BELOW NORMAL. USING THE LOCAL TEMP
FORECAST TECHNIQUE FOR A DRY ADIABATIC LOW LEVEL THERMAL PROFILE AND
FACTORING IN SCATTERED CLOUDS... EXPECT HIGHS OF 47-52... WHICH IS
CLOSE TO THE RECORD LOW MAXIMUM TEMPS FOR THAT DATE (49 AT RDU AND
48 AT GSO... BOTH IN 1976).
FOR TUESDAY NIGHT: THE MODELS AGREE ON 850 MB TEMPS BOTTOMING OUT AT
-3C TO -5C BY WEDNESDAY MORNING WITH THICKNESSES AROUND 1300 M.
LOCAL RESEARCH SHOWS THAT THESE SORTS OF THICKNESSES HAVE NEARLY
ALWAYS PRODUCED NEAR OR BELOW NORMAL FREEZING. A COUPLE OF FACTORS
FAVOR TEMPS STAYING ABOVE FREEZING HOWEVER. FIRST IS THE FACT THAT
FORECAST SOUNDINGS SHOW VERY LITTLE DECOUPLING... AND SURFACE WINDS
ARE LIKELY TO STAY UP IN THE 4-6 KT RANGE THROUGH MORNING. ALSO... A
STRONG VORTICITY MAXIMUM WILL DIVE THROUGH MI TUESDAY EVENING AND
SWING THROUGH VA LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING... AND
THIS COULD PRODUCE JUST ENOUGH MID AND HIGH CLOUDINESS ACROSS THE
NORTHERN CWA TO KEEP LOWS UP JUST A BIT. GIVEN THE UNCERTAINTY OF
THESE CLOUDS HOWEVER... ALONG WITH THE LOW DEW POINTS AND THE
POSSIBILITY THAT WINDS MAY BRIEFLY DROP OFF... HAVE ELECTED TO POST
A FREEZE WATCH FOR THE NORTHWEST COUNTIES OF CENTRAL NC... INCLUDING
ROXBORO... CHAPEL HILL... THE TRIAD AREA... AND ALBEMARLE. EXPECT
LOWS OF 28-33.
FOR WEDNESDAY THROUGH THURSDAY: ADDITIONAL SHEARED BUT STRONG
VORTICITY MAXIMA WILL DROP THROUGH NRN NC DURING THIS TIME. THE
NAM/GFS DISAGREE ON THE DETAILS OF TIMING AND INTENSITY BUT BOTH
PLACE THE UPPER JET CORE THROUGH NC WITH MODERATE MOISTURE AND LIFT
ALOFT... WHICH SHOULD KEEP THE RISK OF AT LAST SOME MID AND HIGH
CLOUDINESS OVER THE CWA. THE DRY ADIABATIC TEMP SCHEME ALONG WITH
LOW LEVEL THICKNESS PROGS GIVE HIGHS OF JUST 49-54. THE MID LEVEL
TROUGH AXIS BEGINS TO SLOWLY LIFT OUT WEDNESDAY NIGHT/THURSDAY...
AND THE SURFACE RIDGE NOSES IN FROM THE SW CAUSING SURFACE WINDS TO
LESSEN. LOW TEMPS NEAR OR BELOW FREEZING ARE LIKELY BY DAWN
THURSDAY... AND MORE FREEZE WATCHES OR WARNINGS ARE PROBABLY FOR
WEDNESDAY NIGHT. EXPECT HIGHS OF AROUND 60 TO THE LOWER 60S ON
THURSDAY UNDER CONSIDERABLE SUNSHINE. -GIH
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 250 PM MONDAY...
FOR THURSDAY NIGHT/FRIDAY: LOW LEVEL THICKNESSES FINALLY CLIMB OUT
OF THE BASEMENT AS SURFACE RIDGING SHIFTS TO THE CAROLINA COAST
THURSDAY NIGHT AND HOLDS ACROSS THE SOUTHEAST STATES THROUGH FRIDAY
NIGHT. WEAK ANTICYCLONIC FLOW IN THE MID LEVELS ALONG WITH BELOW
NORMAL PRECIPITABLE WATER WILL DOMINATE THE SOUTHEAST STATES THROUGH
FRIDAY... THUS EXPECT MINIMAL CLOUD COVER AND MODERATING TEMPS WITH
NEAR NORMAL HIGHS OF 65-70 FRIDAY... AFTER MORNING LOWS OF 33-37.
FOR SATURDAY THROUGH MONDAY: THE MODELS AGREE ON ANOTHER MID LEVEL
POLAR TROUGH SWINGING THROUGH THE GREAT LAKES/ST LAWRENCE VALLEY AND
DEEPENING ALONG THE EASTERN STATES SUNDAY/MONDAY. BUT THE AGREEMENT
ENDS THERE AS THE 00Z/27 ECMWF IS BY FAR THE DEEPEST... CLOSING OFF
A MID LEVEL VORTEX JUST OFF THE MID ATLANTIC COAST. THE 06Z/27 GFS
IS MUCH LESS AMPLIFIED... AND THE 12Z RUN IS EVEN LESS SO. THIS WILL
IMPACT HOW MUCH COLD AIR IS PUSHED BY A STRONG DAMMING HIGH DOWN THE
EASTERN SEABOARD SUNDAY/MONDAY. GIVEN THE WEAKER TREND OF THE GFS
AND GOOD AGREEMENT AMONG GFS ENSEMBLE MEMBERS... WILL FAVOR THE
WEAKER TROUGH SOLUTION. EXPECT RATHER MILD HIGHS SATURDAY... 66-71
AS THICKNESSES ARE NEAR TO JUST ABOVE NORMAL... THEN WILL HAVE AN
INCREASE IN CLOUDS TO PARTLY CLOUDY AND A COOLDOWN TO HIGHS OF 58-64
FOR SUNDAY/MONDAY. IF THE GFS CONTINUES ITS TREND OF HIGHER MID
LEVEL HEIGHTS IN SUBSEQUENT RUNS... SUNDAY/MONDAY TEMPS COULD END UP
CLOSER TO NORMAL (AROUND MID 60S THIS TIME OF YEAR). -GIH
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 840 PM MONDAY...
LARGE SCALE LIFT AHEAD OF A VERY DYNAMIC UPPER LEVEL TROUGH WILL
CONTINUE TO SUPPORT RAIN MIXED WITH SLEET AND MVFR/IFR CONDITIONS
OVER EASTERN NC AND VA THROUGH THIS EVENING... WHILE CONDITIONS
WILL REMAIN VFR WESTWARD AT CENTRAL NC TERMINALS THROUGH THE VALID
TAF PERIOD. NORTHWESTERLY SURFACE WINDS SHOULD REMAIN IN THE 5 TO 12
KT RANGE OVERNIGHT... AS THE MSLP GRADIENT TIGHTENS IN RESPONSE TO
SURFACE HIGH PRESSURE BUILDING INTO THE REGION FROM THE WEST AND THE
EXPECTED RAPID INTENSIFICATION OF A COASTAL LOW OFF THE MID ATLANTIC
COAST. SKIES SHOULD REMAIN GENERALLY CLEAR ACROSS THE FORECAST AREA
TONIGHT... AS THE AFOREMENTIONED CLOUD COVER CONTINUES TO PIVOT
TOWARD THE COAST WHILE DOWNSLOPE FLOW EAST OF THE MOUNTAINS WILL
TEND TO DISSIPATE UPSTREAM CLOUDINESS ALONG AND WEST OF THE
MOUNTAINS.
FOR TUESDAY... SUSTAINED NORTHWEST WINDS WILL STRENGTHEN INTO THE 15
TO 20 KT RANGE WITH FREQUENT GUSTS BETWEEN 25 AND 30 KTS LATE
MORNING THROUGH THE AFTERNOON... AS THE MSLP GRADIENT CONTINUES TO
TIGHTEN AND STRONGER WINDS ALOFT (~30 KTS) IN THE DEEPENING MIXED
ARE MIXED DOWNWARD. SCATTERED TO BRIEFLY BROKEN INSTABILITY CUMULUS
AND STRATOCUMULUS IN THE 4 TO 7 THSD FT RANGE SHOULD DEVELOP WITH
SURFACE HEATING... AS THE COLD POOL ALOFT AND RESULTANT STEEP MID
LEVEL ASSOCIATED WITH THE UPPER TROUGH SPREADS ACROSS THE REGION.
LOOKING BEYOND 00Z/29TH... A DEEP EASTERN U.S. TROUGH WILL GRADUALLY
LIFT NORTHEASTWARD DURING THE MID WEEK PERIOD... WITH A WEAKER W TO
NW UPPER FLOW EXPECTED TO DOMINATE THE WEATHER TOWARD THE END OF THE
WORK WEEK. THIS SHOULD RESULT IN GENERALLY FAIR WEATHER AND VFR
CONDITIONS DURING THE PERIOD. -MWS
&&
.FIRE WEATHER...
AS OF 230 PM MONDAY...
MIXING HEIGHTS INCREASED TO OVER 5000 FT AGL BEHIND THE PASSAGE OF A
STRONG COLD FRONT THROUGH THE AREA THIS AFTERNOON... AND RELATIVE
HUMIDITIES DROPPED TO 30-40% AS DEW POINTS PLUNGED INTO THE 20S AND
EVEN UPPER TEENS. THESE CONDITIONS HOWEVER ARE BELOW ANY RED FLAG
THREAT. LOOKING AHEAD TO TUESDAY... MIXED LAYER DEPTHS ARE EXPECTED
TO INCREASE TO AROUND 6800-8000 FT AGL WITH HIGHER WINDS AS WELL...
20-30 KTS THROUGH THE LAYER. SURFACE RH TUESDAY SHOULD BE CLOSE TO
TODAY`S MINIMUM RH... BOTTOMING OUT AROUND 30-35%... AS THE LOWER
DEW POINTS ARE BALANCED OUT BY CHILLY TEMPERATURES ONLY TOPPING OUT
IN THE UPPER 40S TO LOWER 50S AREAWIDE. AGAIN...THESE CONDITIONS
ARE ALL WELL BELOW RED FLAG CRITERIA... BUT FORESTRY OFFICIALS AND
OTHERS CONTEMPLATING BURNING THIS WEEK SHOULD CHECK THE LATEST
FORECASTS AND CONDITIONS CAREFULLY AND PROCEED WITH CAUTION. THIS
INFORMATION WILL BE MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK...
HOWEVER A SPECIAL WEATHER STATEMENT IS NOT NEEDED DUE TO THE
MARGINAL CONDITIONS. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR
NCZ007-021>024-038-039-073.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BLAES
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...MWS
FIRE WEATHER...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 PM EDT MON OCT 27 2008
.SYNOPSIS...
A BRISK AND CHILLY AIR MASS WILL CONTINUE TO BUILD INTO THE REGION
THROUGH WEDNESDAY... BRINGING MUCH BELOW NORMAL TEMPERATURES. A
GRADUAL WARMING TREND BACK TOWARD SEASONAL NORMALS WILL FOLLOW
STARTING THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 PM MONDAY...
INTERESTING DAY ON THE NEAR TERM DESK.
LATEST SFC ANALYSIS AT 18Z PLACES THE COLD FRONT IN THE COASTAL
PLAIN OF NC FROM KASJ TO KRWI TO KFAY TO KLBT. AHEAD OF THE FRONT
TEMPS WARMED INTO THE MID 60S ACROSS THE EASTERN SANDHILLS AND
PORTIONS OF THE SOUTHERN AND CENTRAL COASTAL PLAIN WITH TEMPS
REACHING 72 AT KEDE AND 70 AT KPGV. SFC FLOW HAS BECOME NW ACROSS
THE RAH CWA AND COLD/DRY ADVECTION IS UNDERWAY. LATEST 1755Z AMDAR
SOUNDING AT KRDU SHOWS THE SFC BASED COOLING IS STILL FAIRLY SHALLOW
AND EXTENDS ONLY UP TO AROUND 2K FEET.
MAIN FEATURE OF INTEREST THIS AFTERNOON HAS BEEN A DEVELOPING BAND
OF CLOUDS AND LIGHT PRECIP ACROSS VA AND NORTHERN NC. WV IMAGERY
DEPICTS A ROBUST SHORT WAVE MOVING ACROSS THE BLUE RIDGE OF NW VA
WITH A BAROCLINIC LEAF PATTERN NOTED EARLIER ON RADAR AND SAT
IMAGERY. SHORT TERM NWP GUIDANCE SUGGESTS THAT THIS AREA OF PRECIP
WILL LIKELY EXPAND SE LATER THIS AFTN AND EVE. LOW/MID LEVEL
FRONTOGENESIS COUPLED WITH UPPER LEVEL FORCING ASSOCIATED WITH THE
UPPER LEVEL TROF AND UPPER DIVERGENCE IN THE LEFT EXIT REGION OF AN
INTENSIFYING H25 140 KT JET IS PRODUCING A DEEP LAYER OF OMEGA.
SHALLOW NATURE OF MOISTURE SHOULD LIMIT THE AMOUNT OF PRECIP BUT
FEEL THAT THE IMPRESSIVE LIFT SHOULD BE ABLE TO SQUEEZE A FEW
SHOWERS OR SPRINKLES OUT THIS EVENING...ESPECIALLY ACROSS THE N AND
CENTRAL COASTAL PLAIN. HAD SEVERAL REPORTS OF SLEET IN THE TRIAD
AREA PASSED ALONG FROM A TRIAD TV MET. SLEET WAS REPORTED BETWEEN
1245 AND 145 PM...AS PRECIPITATION DROPS FELL INTO THE DRY AIRMASS
IT BEGAN TO EVAORPATE AND COOL. THE WET BULB FREEZING LEVELS WERE IN
THE 2 TO 3K FT LEVEL ALLOWING SOME PELLETS TO FORM.
THE UPPER TROUGH AXIS SWINGS THROUGH THE CAROLINAS AND VIRGINIAS
OVERNIGHT ALLOWING SKIES TO CLEAR SOMEWHAT. COLD ADVECTION WILL
CONTINUE TONIGHT WITH THE MAIN THRUST COMING THIS EVENING. THICKNESS
VALUES DROP INTO THE 1300-1305 M RANGE BY TUE MORNING. STATISTICAL
GUIDANCE IN FAIRLY GOOD AGREEMENT WITH LOWS IN THE 33 TO 37 RANGE.
AIRMASS SHOULD REMAIN MIXED AND SCT TO BKN CLOUD COVER SHOULD
PREVENT RADIATIONAL COOLING AND FROST FORMATION. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
AS OF 305 PM MONDAY...
FOR TUESDAY: THE MID LEVEL VORTEX IS EXPECTED TO BE OVER THE
DELMARVA PENINSULA BY TUESDAY MORNING. CENTRAL NC GETS IN THE HEART
OF THE MID LEVEL THERMAL TROUGH WITH 500 MB TEMPS DROPPING TO -30C
TO -32C. FORECAST SOUNDINGS ARE RATHER UNSTABLE WITH TOTAL TOTALS
REACHING 50-54... 1000-850 MB LAPSE RATES OVER 9.5 C/KM... AND
850-500 MB LAPSE RATES OVER 7 C/KM. SCATTERED CONVECTIVE CLOUDINESS
IS EXPECTED TO DEVELOP AND JUST A FEW HUNDRED JOULES/KG OF CAPE
COULD BE ENOUGH FOR PATCHY SPRINKLES... BUT WITH SUCH A LOW
PRECIPITABLE WATER (JUST AROUND A THIRD OF AN INCH) AND DRY SURFACE
BASED LAYER... WILL REFRAIN FROM INCLUDING ANY PRECIP CHANCES AT
THIS TIME. OF POSSIBLY GREATER CONCERN WILL BE THE WINDS TOMORROW...
AS FORECAST SOUNDINGS SHOW A VERY DEEP MIXED LAYER UP TO 750-700 MB
MB WITH BOUNDARY LAYER WINDS INCREASING TO 15-20 KTS AND WINDS AT
THE TOP OF THE MIXED LAYER AROUND 30-32 KTS. STRONG SUBSIDENCE IS
LIKELY TO BRING THESE WINDS DOWN TO THE SURFACE AS EARLY AS TUESDAY
MORNING... AND WE EXPECT SUSTAINED WINDS OVER 15 MPH WITH GUSTS OF
30-35 KTS POSSIBLE. FORTUNATELY THE PROBABILITY OF LOCALLY STRONGER
WINDS SEEMS TO HAVE DIMINISHED AS THE POTENTIAL FOR AN INTRUSION OF
STRATOSPHERIC AIR TUESDAY NOW APPEARS LESS LIKELY THAN IT ONCE DID.
SINCE THE 130-140 KT UPPER JET CORE SHOULD BE WELL TO OUR
SOUTHEAST... THE ASSOCIATED TROPOPAUSE FOLD AND ANY
GROUNDWARD-DIRECTED HIGH POTENTIAL VORTICITY SHOULD LIKEWISE BE TO
OUR SOUTH. TUESDAY SHOULD EASILY BE THE COLDEST DAY IN THIS
STRETCH... AND THE MODELS HAVE BEEN CONSISTENT SHOWING LOW LEVEL
THICKNESSES NEARLY 50 METERS BELOW NORMAL. USING THE LOCAL TEMP
FORECAST TECHNIQUE FOR A DRY ADIABATIC LOW LEVEL THERMAL PROFILE AND
FACTORING IN SCATTERED CLOUDS... EXPECT HIGHS OF 47-52... WHICH IS
CLOSE TO THE RECORD LOW MAXIMUM TEMPS FOR THAT DATE (49 AT RDU AND
48 AT GSO... BOTH IN 1976).
FOR TUESDAY NIGHT: THE MODELS AGREE ON 850 MB TEMPS BOTTOMING OUT AT
-3C TO -5C BY WEDNESDAY MORNING WITH THICKESSES AROUND 1300 M. LOCAL
RESEARCH SHOWS THAT THESE SORTS OF THICKNESSES HAVE NEARLY ALWAYS
PRODUCED NEAR OR BELOW NORMAL FREEZING. A COUPLE OF FACTORS FAVOR
TEMPS STAYING ABOVE FREEZING HOWEVER. FIRST IS THE FACT THAT
FORECAST SOUNDINGS SHOW VERY LITTLE DECOUPLING... AND SURFACE WINDS
ARE LIKELY TO STAY UP IN THE 4-6 KT RANGE THROUGH MORNING. ALSO... A
STRONG VORTICITY MAXIMUM WILL DIVE THROUGH MI TUESDAY EVENING AND
SWING THROUGH VA LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING... AND
THIS COULD PRODUCE JUST ENOUGH MID AND HIGH CLOUDINESS ACROSS THE
NORTHERN CWA TO KEEP LOWS UP JUST A BIT. GIVEN THE UNCERTAINTY OF
THESE CLOUDS HOWEVER... ALONG WITH THE LOW DEW POINTS AND THE
POSSIBILITY THAT WINDS MAY BRIEFLY DROP OFF... HAVE ELECTED TO POST
A FREEZE WATCH FOR THE NORTHWEST COUNTIES OF CENTRAL NC... INCLUDING
ROXBORO... CHAPEL HILL... THE TRIAD AREA... AND ALBEMARLE. EXPECT
LOWS OF 28-33.
FOR WEDNESDAY THROUGH THURSDAY: ADDITIONAL SHEARED BUT STRONG
VORTICITY MAXIMA WILL DROP THROUGH NRN NC DURING THIS TIME. THE
NAM/GFS DISAGREE ON THE DETAILS OF TIMING AND INTENSITY BUT BOTH
PLACE THE UPPER JET CORE THROUGH NC WITH MODERATE MOISTURE AND LIFT
ALOFT... WHICH SHOULD KEEP THE RISK OF AT LAST SOME MID AND HIGH
CLOUDINESS OVER THE CWA. THE DRY ADIABATIC TEMP SCHEME ALONG WITH
LOW LEVEL THICKNESS PROGS GIVE HIGHS OF JUST 49-54. THE MID LEVEL
TROUGH AXIS BEGINS TO SLOWLY LIFT OUT WEDNESDAY NIGHT/THURSDAY...
AND THE SURFACE RIDGE NOSES IN FROM THE SW CAUSING SURFACE WINDS TO
LESSEN. LOW TEMPS NEAR OR BELOW FREEZING ARE LIKELY BY DAWN
THURSDAY... AND MORE FREEZE WATCHES OR WARNINGS ARE PROBABLY FOR
WEDNESDAY NIGHT. EXPECT HIGHS OF AROUND 60 TO THE LOWER 60S ON
THURSDAY UNDER CONSIDERABLE SUNSHINE. -GIH
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 250 PM MONDAY...
FOR THURSDAY NIGHT/FRIDAY: LOW LEVEL THICKNESSES FINALLY CLIMB OUT
OF THE BASEMENT AS SURFACE RIDGING SHIFTS TO THE CAROLINA COAST
THURSDAY NIGHT AND HOLDS ACROSS THE SOUTHEAST STATES THROUGH FRIDAY
NIGHT. WEAK ANTICYCLONIC FLOW IN THE MID LEVELS ALONG WITH BELOW
NORMAL PRECIPITABLE WATER WILL DOMINATE THE SOUTHEAST STATES THROUGH
FRIDAY... THUS EXPECT MINIMAL CLOUD COVER AND MODERATING TEMPS WITH
NEAR NORMAL HIGHS OF 65-70 FRIDAY... AFTER MORNING LOWS OF 33-37.
FOR SATURDAY THROUGH MONDAY: THE MODELS AGREE ON ANOTHER MID LEVEL
POLAR TROUGH SWINGING THROUGH THE GREAT LAKES/ST LAWRENCE VALLEY AND
DEEPENING ALONG THE EASTERN STATES SUNDAY/MONDAY. BUT THE AGREEMENT
ENDS THERE AS THE 00Z/27 ECMWF IS BY FAR THE DEEPEST... CLOSING OFF
A MID LEVEL VORTEX JUST OFF THE MID ATLANTIC COAST. THE 06Z/27 GFS
IS MUCH LESS AMPLIFIED... AND THE 12Z RUN IS EVEN LESS SO. THIS WILL
IMPACT HOW MUCH COLD AIR IS PUSHED BY A STRONG DAMMING HIGH DOWN THE
EASTERN SEABOARD SUNDAY/MONDAY. GIVEN THE WEAKER TREND OF THE GFS
AND GOOD AGREEMENT AMONG GFS ENSEMBLE MEMBERS... WILL FAVOR THE
WEAKER TROUGH SOLUTION. EXPECT RATHER MILD HIGHS SATURDAY... 66-71
AS THICKNESSES ARE NEAR TO JUST ABOVE NORMAL... THEN WILL HAVE AN
INCREASE IN CLOUDS TO PARTLY CLOUDY AND A COOLDOWN TO HIGHS OF 58-64
FOR SUNDAY/MONDAY. IF THE GFS CONTINUES ITS TREND OF HIGHER MID
LEVEL HEIGHTS IN SUBSEQUENT RUNS... SUNDAY/MONDAY TEMPS COULD END UP
CLOSER TO NORMAL (AROUND MID 60S THIS TIME OF YEAR). -GIH
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 150 PM MONDAY...
VFR CONDITIONS WILL GENERALLY PERSIST THROUGH TUESDAY AFTN ALTHOUGH
VSBYS CIGS COULD APPROACH MVFR AT KRWI AND POSSIBLY KRDU LATE THIS
AFTN AND EVE. A DEEPENING UPPER TROF WILL MOVE ACROSS CENTRAL NC
THROUGH TUE NIGHT. A STRONG COLD FRONT ASSOCIATED WITH THE UPPER
TROF MOVED THROUGH CENTRAL NC BETWEEN 12 AND 17Z. COLD ADVECTION IS
UNDERWAY BEHIND THE FRONT AND WINDS HAVE BECOME NW AT 10 TO 15 KTS
WITH GUSTS TO 25 KTS.
A WAVE IN THE UPPER FLOW AND DIVERGENCE ALOFT IS PRODUCING A
NORTH-SOUTH BAND OF CLOUDINESS AND LIGHT PRECIP ACROSS CENT VA AT
17Z THE EXTENDS INTO NORTH CENTRAL NC. DEPTH OF THE MOISTURE IS
LIMITED BUT FAIRLY IMPRESSIVE LIFT WITH THIS SYSTEM WILL RESULT IN
SOME LIGHT SHOWERS OR SPRINKLES. THIS BAND OF CLOUDINESS AND PRECIP
WILL SHIFT E AND EXPAND DURING THE LATE AFTN AND EVE. MOST OF THE
FORCING AND LIFT SHOULD BE EXITING CENTRAL NC BY AROUND 06Z WHICH
WILL ALLOW LOW-MID CLOUD DECK TO SCT A BIT. WINDS SHOULD REMAIN UP
OVERNIGHT BUT RELAX TO BETWEEN 5 AND 8 KTS.
THE UPPER TROUGH DEEPENS AND BECOMES NEGATIVELY TILTED ON ON TUES.
DESPITE LIMITED MOISTURE A PERIOD OF BROKEN STRATOCU IS POSSIBLE
DURING THE LATE MORN AND AFTN. CLOUDINESS SHOULD BE MOST WIDESPREAD
AND THICKEST ACROSS N NC WHERE A SPRINKLE OR RAIN SHOWER IS POSSIBLE
DUE TO A LITTLE BETTER MOISTURE AND LOW LEVEL INSTABILITY.
DEEP EASTERN U.S. TROUGH GRADUALLY LIFTS DURING THE MID WEEK PERIOD
WITH A WEAKER W TO NW UPPER FLOW DOMINATING THE WEATHER TOWARD THE
END OF THE WORK WEEK. THIS SHOULD RESULT IN GENERALLY FAIR WEATHER
DURING PERIOD. -BLAES
&&
.FIRE WEATHER...
AS OF 230 PM MONDAY...
MIXING HEIGHTS INCREASED TO OVER 5000 FT AGL BEHIND THE PASSAGE OF A
STRONG COLD FRONT THROUGH THE AREA THIS AFTERNOON... AND RELATIVE
HUMIDITIES DROPPED TO 30-40% AS DEW POINTS PLUNGED INTO THE 20S AND
EVEN UPPER TEENS. THESE CONDITIONS HOWEVER ARE BELOW ANY RED FLAG
THREAT. LOOKING AHEAD TO TUESDAY... MIXED LAYER DEPTHS ARE EXPECTED
TO INCREASE TO AROUND 6800-8000 FT AGL WITH HIGHER WINDS AS WELL...
20-30 KTS THROUGH THE LAYER. SURFACE RH TUESDAY SHOULD BE CLOSE TO
TODAY`S MINIMUM RH... BOTTOMING OUT AROUND 30-35%... AS THE LOWER
DEW POINTS ARE BALANCED OUT BY CHILLY TEMPERATURES ONLY TOPPING OUT
IN THE UPPER 40S TO LOWER 50S AREAWIDE. AGAIN...THESE CONDITIONS
ARE ALL WELL BELOW RED FLAG CRITERIA... BUT FORESTRY OFFICIALS AND
OTHERS CONTEMPLATING BURNING THIS WEEK SHOULD CHECK THE LATEST
FORECASTS AND CONDITIONS CAREFULLY AND PROCEED WITH CAUTION. THIS
INFORMATION WILL BE MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK...
HOWEVER A SPECIAL WEATHER STATEMENT IS NOT NEEDED DUE TO THE
MARGINAL CONDITIONS. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR
NCZ007-021>024-038-039-073.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BLAES
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...BLAES
FIRE WEATHER...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT MON OCT 27 2008
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS CENTRAL NC TODAY. NORTHWEST WINDS
BEHIND THE FRONT WILL USHER MUCH COLDER AIR INTO THE REGION. WELL
BELOW NORMAL TEMPERATURES CAN BE EXPECTED ON TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 PM MONDAY...
INTERESTING DAY ON THE NEAR TERM DESK.
LATEST SFC ANALYSIS AT 18Z PLACES THE COLD FRONT IN THE COASTAL
PLAIN OF NC FROM KASJ TO KRWI TO KFAY TO KLBT. AHEAD OF THE FRONT
TEMPS WARMED INTO THE MID 60S ACROSS THE EASTERN SANDHILLS AND
PORTIONS OF THE SOUTHERN AND CENTRAL COASTAL PLAIN WITH TEMPS
REACHING 72 AT KEDE AND 70 AT KPGV. SFC FLOW HAS BECOME NW ACROSS
THE RAH CWA AND COLD/DRY ADVECTION IS UNDERWAY. LATEST 1755Z AMDAR
SOUNDING AT KRDU SHOWS THE SFC BASED COOLING IS STILL FAIRLY SHALLOW
AND EXTENDS ONLY UP TO AROUND 2K FEET.
MAIN FEATURE OF INTEREST THIS AFTERNOON HAS BEEN A DEVELOPING BAND
OF CLOUDS AND LIGHT PRECIP ACROSS VA AND NORTHERN NC. WV IMAGERY
DEPICTS A ROBUST SHORT WAVE MOVING ACROSS THE BLUE RIDGE OF NW VA
WITH A BAROCLINIC LEAF PATTERN NOTED EARLIER ON RADAR AND SAT
IMAGERY. SHORT TERM NWP GUIDANCE SUGGESTS THAT THIS AREA OF PRECIP
WILL LIKELY EXPAND SE LATER THIS AFTN AND EVE. LOW/MID LEVEL
FRONTOGENESIS COUPLED WITH UPPER LEVEL FORCING ASSOCIATED WITH THE
UPPER LEVEL TROF AND UPPER DIVERGENCE IN THE LEFT EXIT REGION OF AN
INTENSIFYING H25 140 KT JET IS PRODUCING A DEEP LAYER OF OMEGA.
SHALLOW NATURE OF MOISTURE SHOULD LIMIT THE AMOUNT OF PRECIP BUT
FEEL THAT THE IMPRESSIVE LIFT SHOULD BE ABLE TO SQUEEZE A FEW
SHOWERS OR SPRINKLES OUT THIS EVENING...ESPECIALLY ACROSS THE N AND
CENTRAL COASTAL PLAIN. HAD SEVERAL REPORTS OF SLEET IN THE TRIAD
AREA PASSED ALONG FROM A TRIAD TV MET. SLEET WAS REPORTED BETWEEN
1245 AND 145 PM...AS PRECIPITATION DROPS FELL INTO THE DRY AIRMASS
IT BEGAN TO EVAORPATE AND COOL. THE WET BULB FREEZING LEVELS WERE IN
THE 2 TO 3K FT LEVEL ALLOWING SOME PELLETS TO FORM.
THE UPPER TROUGH AXIS SWINGS THROUGH THE CAROLINAS AND VIRGINIAS
OVERNIGHT ALLOWING SKIES TO CLEAR SOMEWHAT. COLD ADVECTION WILL
CONTINUE TONIGHT WITH THE MAIN THRUST COMING THIS EVENING. THICKNESS
VALUES DROP INTO THE 1300-1305 M RANGE BY TUE MORNING. STATISTICAL
GUIDANCE IN FAIRLY GOOD AGREEMENT WITH LOWS IN THE 33 TO 37 RANGE.
AIRMASS SHOULD REMAIN MIXED AND SCT TO BKN CLOUD COVER SHOULD
PREVENT RADIATIONAL COOLING AND FROST FORMATION. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 255 AM MONDAY...
THE HEART OF THE 500 MB TROUGH WILL BE DIRECTLY OVERHEAD TUESDAY
WITH 500 MB TEMPS EXPECTED TO BE -30C TO -32C. 1000-700 MB LAPSE
RATES ARE IMPRESSIVE TUESDAY AFTERNOON...APPROACHING 9 C/KM.
SUFFICIENT MOISTURE NEAR 850 MB SHOULD LEAD TO THE DEVELOPMENT OF
CONSIDERABLE COLD AIR STRATOCU BY THE AFTERNOON...WITH SKIES
POSSIBLY BECOMING MOSTLY CLOUDY. TAKING INTO ACCOUNT THE INCREASED
CLOUD COVER ALONG WITH THICKNESSES ABOUT 50 METERS BELOW
NORMAL....HIGH TEMPERATURES WILL STRUGGLE TO CLIMB. WILL GO WITH
HIGHS OF 48-53. THESE TEMPS WILL BE CLOSE TO THE RECORD LOW MAXES
FOR THE DAY (48 AT GSO AND 49 AT RDU...BOTH OCCURRING IN 1976.) IF
THAT WAS NOT COLD ENOUGH FOR LATE OCTOBER...BREEZY CONDITIONS ARE
EXPECTED TO MAKE IT FEEL EVEN COLDER. WINDS IN THE DEEP MIXED
LAYER INCREASE TO 25-30 KT AND THESE WINDS SHOULD HAVE LITTLE
TROUBLE MIXING TO THE SFC DUE TO THE STEEP LOW LEVEL LAPSE RATES.
THEREFORE...FREQUENT GUSTS OF UP TO 25 MPH ARE ANTICIPATED TUESDAY
AFTERNOON.
THE FIRST FREEZE OF THE SEASON IS POSSIBLE ON TUESDAY NIGHT. LOW
LEVEL THICKNESSES DROP TO AROUND 1290M...WHICH AS WE HAVE STATED
IN PAST DISCUSSIONS...ALMOST ALWAYS RESULTS IN FREEZING
TEMPERATURES. IT WILL BE TOUGH TO DECOUPLE THE BOUNDARY LAYER
SINCE THE CENTER OF THE SFC HIGH WILL STILL BE LOCATED WELL WEST
OF THE REGION...AND THIS WILL LIKELY KEEP TEMPS FROM DROPPING AS
MUCH AS THEY OTHERWISE WOULD. HOWEVER...STILL FEEL RATHER
CONFIDENT IN LOWS OF 29-33 GIVEN THE GREATLY ANOMALOUS NATURE OF
THIS WEATHER PATTERN. A FREEZE WATCH MAY BECOME NECESSARY FOR
TUESDAY NIGHT.
IN PRIOR DAYS IT APPEARED THAT WEDNESDAY WOULD SEE SOME MODIFICATION
TO THE MUCH BELOW NORMAL TEMPERATURES. HOWEVER... MODELS ARE NOW
MUCH SLOWER MOVING OUT THE EAST COAST TROUGH AS THE GUIDANCE ALL
AGREES ON THE DEVELOPMENT OF DOWNSTREAM BLOCKING OVER THE DAVIS
STRAITS. LOW LEVEL THICKNESSES ARE NOW PROGGED TO ONLY RISE TO
1310-1315 METERS...LOWER THAN PREVIOUSLY EXPECTED AND VERY SIMILAR
TO VALUES WE WILL LIKELY SEE ON TUESDAY. THEREFORE...WILL ONLY
BRING HIGHS UP TO 52-55...AND THIS MAY EVEN BE TOO WARM...
ESPECIALLY ACROSS THE NORTHERN PIEDMONT AND SOUTHEAST COASTAL
PLAIN.
IF FREEZING TEMPS DO NOT OCCUR TUESDAY NIGHT...THEY ARE LOOKING
INCREASINGLY LIKELY FOR WEDNESDAY NIGHT/THURSDAY MORNING. THE SFC
HIGH WILL SHIFT OVERHEAD...RELAXING THE PRESSURE GRADIENT AND
ALLOWING FOR BOUNDARY LAYER DECOUPLING. LIGHT TO CALM WINDS
COMBINED WITH CLEAR SKIES WILL OPTIMIZE RADIATION COOLING AND LOWS
OF 27-32 ARE FORECAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 315 AM MONDAY...
THURSDAY...MID/UPPER LEVEL HEIGHTS REBOUND AS L/W TROUGH LIFTS TO
THE E-NE. THIS SIGNALS BEGINNING OF WARMING TREND WITH LOW LEVEL
THICKNESSES RECOVERING INTO THE 1340-1345 RANGE BY AFTERNOON. THIS
TRANSLATES TO AFTERNOON TEMPS 5-7 DEGREES BELOW NORMAL (UPPER 50S NW
TO LOWER 60S S). BY FRI S/W RIDGE OVER THE REGION. MODEST SUBSIDENCE
WARMING FROM THIS FEATURE SHOULD ALLOW TEMPS TO RETURN TO NEAR
NORMAL LEVELS (65-70).
SATURDAY-SUNDAY...00Z ECMWF AND 00Z GFS IN GOOD AGREEMENT DEPICTING
ANOTHER DECENT POLAR S/W DIGGING SEWD FROM GREAT LAKES INTO THE MID
ATLANTIC. THIS FEATURE PROGGED TO DRAG A COLD FRONT ACROSS OUR
REGION LATE SATURDAY OR EARLY SUNDAY. APPEARS TO BE ENOUGH MOISTURE
TO GENERATE CLOUDS AND POSSIBLY SOME LIGHT PRECIP. MODEL GUIDANCE
DIVERGENCES SUN AS GFS ATTEMPTS TO CLOSE OFF AN UPPER LEVEL LOW IN
OUR VICINITY. THIS WOULD KEEP CLOUDS/PRECIP CHANCES CONTINUING INTO
SUNDAY AND SUNDAY NIGHT. ECMWF ALSO CLOSES OFF AN UPPER LEVEL LOW
BUT OFFSHORE. CIRCULATION AROUND THIS FEATURE WOULD ALLOW DRY AIR
RIDGE TO NOSE SOUTHWARD INTO CENTRAL NC...RESULTING IN COOLER DRIER
CONDITIONS. DUE TO UNCERTAINTY OF TIMING/POSITION....WILL LIMIT POPS
TO NO HIGHER THAN SLIGHT CHANCE FOR SATURDAY NIGHT AND SUNDAY AS A
BLEND OF THE TWO MODELS WOULD RESULT IN SOME CLOUDINESS AND
POSSIBLY SOME LIGHT PRECIP.
SW LOW LEVEL FLOW AHEAD OF FRONT SHOULD MAINTAIN MILD TEMPS OVER
REGION SATURDAY WITH A COOL DOWN STILL ANTICIPATED FOR SUN.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 150 PM MONDAY...
VFR CONDITIONS WILL GENERALLY PERSIST THROUGH TUESDAY AFTN ALTHOUGH
VSBYS CIGS COULD APPROACH MVFR AT KRWI AND POSSIBLY KRDU LATE THIS
AFTN AND EVE. A DEEPENING UPPER TROF WILL MOVE ACROSS CENTRAL NC
THROUGH TUE NIGHT. A STRONG COLD FRONT ASSOCIATED WITH THE UPPER
TROF MOVED THROUGH CENTRAL NC BETWEEN 12 AND 17Z. COLD ADVECTION IS
UNDERWAY BEHIND THE FRONT AND WINDS HAVE BECOME NW AT 10 TO 15 KTS
WITH GUSTS TO 25 KTS.
A WAVE IN THE UPPER FLOW AND DIVERGENCE ALOFT IS PRODUCING A
NORTH-SOUTH BAND OF CLOUDINESS AND LIGHT PRECIP ACROSS CENT VA AT
17Z THE EXTENDS INTO NORTH CENTRAL NC. DEPTH OF THE MOISTURE IS
LIMITED BUT FAIRLY IMPRESSIVE LIFT WITH THIS SYSTEM WILL RESULT IN
SOME LIGHT SHOWERS OR SPRINKLES. THIS BAND OF CLOUDINESS AND PRECIP
WILL SHIFT E AND EXPAND DURING THE LATE AFTN AND EVE. MOST OF THE
FORCING AND LIFT SHOULD BE EXITING CENTRAL NC BY AROUND 06Z WHICH
WILL ALLOW LOW-MID CLOUD DECK TO SCT A BIT. WINDS SHOULD REMAIN UP
OVERNIGHT BUT RELAX TO BETWEEN 5 AND 8 KTS.
THE UPPER TROUGH DEEPENS AND BECOMES NEGATIVELY TILTED ON ON TUES.
DESPITE LIMITED MOISTURE A PERIOD OF BROKEN STRATOCU IS POSSIBLE
DURING THE LATE MORN AND AFTN. CLOUDINESS SHOULD BE MOST WIDESPREAD
AND THICKEST ACROSS N NC WHERE A SPRINKLE OR RAIN SHOWER IS POSSIBLE
DUE TO A LITTLE BETTER MOISTURE AND LOW LEVEL INSTABILITY.
DEEP EASTERN U.S. TROUGH GRADUALLY LIFTS DURING THE MID WEEK PERIOD
WITH A WEAKER W TO NW UPPER FLOW DOMINATING THE WEATHER TOWARD THE
END OF THE WORK WEEK. THIS SHOULD RESULT IN GENERALLY FAIR WEATHER
DURING PERIOD. -BLAES
&&
.FIRE WEATHER...
AS OF 315 AM MONDAY...
THE PASSAGE OF THE DRY COLD FRONT THIS MORNING WILL ALLOW MUCH
DRIER SURFACE DEW POINTS TO FILTER INTO THE AREA BY THIS AFTERNOON.
THE MIXED LAYER DEPTH INCREASES TODAY TO AROUND 5000 FT AGL AND
SURFACE RH IS EXPECTED TO BOTTOM OUT AT 23-35%. HOWEVER... WINDS
THROUGH THE MIXED LAYER SHOULD NOT BE PARTICULARLY STRONG (HOLDING
UNDER 20 KTS ACCORDING TO THE LATEST MODEL GUIDANCE) WHEN MIN RH`S
ARE MET THIS AFTERNOON. THESE CONDITIONS ARE BELOW ANY RED FLAG
THREAT BUT ARE STILL WORTH NOTING. TUESDAY MAY BE A SLIGHTLY WORSE
FIRE WEATHER DAY... AS THE MIXED LAYER SHOULD BE A BIT DEEPER
(AROUND 6800-8000 FT AGL) AND SHOULD CONTAIN SLIGHTLY STRONGER
WINDS (POSSIBLE GUSTS TO AROUND 25 MPH)... ALTHOUGH THE SURFACE RH
SHOULD SOMEWHAT HIGHER THAN MONDAY`S MINIMUM RH... AND
TEMPERATURES WILL STRUGGLE TO CLIMB OUT OF THE LOWER 50S. AGAIN...
THESE CONDITIONS ARE ALL WELL BELOW RED FLAG CRITERIA... BUT
FORESTRY OFFICIALS AND OTHERS CONTEMPLATING BURNING THIS WEEK
SHOULD CHECK THE LATEST FORECASTS AND CONDITIONS CAREFULLY AND
PROCEED WITH CAUTION. THIS INFORMATION WILL BE MENTIONED IN THE
HAZARDOUS WEATHER OUTLOOK... HOWEVER A SPECIAL WEATHER STATEMENT
IS NOT NEEDED AT THIS TIME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...JFB
LONG TERM...WSS
AVIATION...BLAES
FIRE WEATHER...JFB/HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 AM EDT SUN OCT 26 2008
.SYNOPSIS...
WEAK HIGH PRESSURE WILL EXTEND ACROSS CENTRAL NORTH CAROLINA TODAY
AND TONIGHT. A STRONG BUT DRY COLD FRONT WILL CROSS THE AREA MONDAY.
WELL BELOW NORMAL TEMPERATURES ARE EXPECTED TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 PM SATURDAY...
UPPER-AIR ANALYSIS SHOWED A STRONG 125KT JET ACROSS CENTRAL NORTH
CAROLINA AT 250MB...HELPING TO MAINTAIN THE BACK EDGE OF CIRRUS FROM
SOUTHWEST TO NORTHEAST ACROSS THE STATE...WHILE POSSIBLY SLOWING THE
850MB FRONT MOVING TO THE EAST. AMDAR SOUNDINGS AT KRDU SUGGESTED
THE FRONT AT THAT LEVEL GRADUALLY MOVING EAST...ALTHOUGH 850MB
UPPER-AIR ANALYSIS INDICATED DECENT MOISTURE AT THAT LEVEL THAT WILL
ONLY GRADUALLY DIMINISH OVERNIGHT AS THE FRONT WEAKENS AND MOVES
SLOWLY EAST OF CENTRAL NORTH CAROLINA BY 12Z. THE LATEST RUC
LOW-LEVEL RH FIELDS ARE FAIRLY CONSISTENT WITH SATELLITE FOG PRODUCT
IMAGES...AS A FEW STRATOCU WERE STILL DEVELOPING AT TIMES TOWARD THE
TRIAD WHILE HANGING ON NICELY PARTICULARLY ALONG AND EAST OF A LINE
FROM ABOUT KRCZ TO KRZZ.
OVERNIGHT...THE UPPER-LEVEL JET WILL MOVE EAST TAKING CIRRUS WITH
IT...WHILE THE WEAKENING 850MB FRONT WILL MOVE EAST AS WELL
ACCOMPANIED BY INCREASING SUBSIDENCE AND DIMINISHING 850MB
CONVERGENCE...HELPING TO SLOWLY REDUCE COVERAGE OF STRATOCU. EXPECT
MOSTLY CLEAR CONDITIONS AROUND THE TRIAD AND TOWARD KTDF...WITH
CLEARING ELSEWHERE ALONG WITH GENERALLY LIGHT SURFACE WINDS VEERING
NORTHWEST. IN A NARROW WINDOW BETWEEN THE ONSET OF CLEARING AND
DIMINISHING SURFACE DEW POINTS...A FEW SITES COULD EXPERIENCE
REDUCED VISIBILITY IN PATCHY FOG...MAINLY IN RURAL...LOW-LYING
AREAS. OVERNIGHT LOWS WILL RANGE FROM THE LOWER TO MID 40S IN THE
NORTHWEST TO LATE NIGHT LOWS AROUND 50 TO THE LOWER 50S IN THE
SOUTHEAST AS DRIER AIR FINALLY WORKS ITS WAY IN LATE AND CLOUDS
BREAK.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 PM SATURDAY...
MILD HIGH PRESSURE BUILDS IN BRIEFLY ON SUNDAY. PLENTY OF SUNSHINE
AND DOWNSLOPE WINDS WILL CONSPIRE TO PRODUCE HIGHS A CATEGORY OR TWO
ABOVE NORMAL... GENERALLY 70 TO 75. THE MILD AIRMASS WILL LINGER
THROUGH SUNDAY NIGHT...BEFORE BEING DISPLACED AS STRONG SHORTWAVE
ENERGY AND A 150KT JET WILL BE DIG INTO AND AMPLIFYING THE UPPER
TROF OVER THE GREAT LAKES. THIS AMPLIFYING TROF WILL ULTIMATELY PUSH
A STRONG SURGE OF COLD AIR ACROSS THE ATLANTIC REGION LATE SUNDAY
NIGHT OR MONDAY MORNING.
THE ENSUING SURGE OF COLD AIR WILL DAMPEN THE DIURNAL TEMPERATURE
RISE ON MONDAY DESPITE STRONG INSOLATION...ESPECIALLY IN THE
NORTHWEST WHICH MAY NOT SEE 60 DEGREES. TIMING DIFFERENCES ARE
EVIDENT AS TO WHEN THE MOMENTUM REALLY SURGES ACROSS THE AREA...BUT
PREFER A 6 HOUR...MOUNTAIN-INDUCED DELAY AS DEPICTED BY THE NAM
SOLUTION. AS SUCH...HIGHS IN THE SOUTHEAST WILL HAVE A CHANCE TO
REACH THE MID 60S BEFORE MAX COLD AIR ADVECTION REALLY KICKS IN BY
AROUND MID DAY. ONGOING COLD AIR ADVECTION WILL KEEP THE ATMOSPHERE
MIXED MONDAY NIGHT...PRECLUDING FROST AS LOWS FALL INTO NEAR
FREEZING IN THE NORTHWEST TO MID 30S ELSEWHERE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 345 PM SATURDAY...
COLD AIR ADVECTION CONTINUES ON TUESDAY USHERING IN THE COLDEST AIR
OF THE WEEK AS THE UPPER TROF ROTATES ACROSS THE EAST COAST.
THICKNESSES BARELY CLIMB ABOVE 1300 METERS...WHICH IS INDICATIVE OF
HIGHS SCRAMBLING TO REACH 50 NORTHWEST TO 55 SOUTHEAST. PRESSURE
GRADIENT RELAXES TUESDAY NIGHT AS THE TROF LIFTS NORTHEAST...THIS
SETS UP IDEAL RADIATIONAL CONDITIONS WITH A COLD DRY AIRMASS IN
PLACE...AND A HARD FREEZE WITH MINS IN THE UPPER 20S LOOKS LIKELY IN
THE NORTHEAST...RANGING TO READINGS RIGHT AROUND FREEZING SOUTHEAST.
THE REMAINDER OF THE WEEK THROUGH SATURDAY WILL BE UNEVENTFUL AS A
SPRAWLING HIGH OVER THE MIDWEST WANDERS EAST AND OVERHEAD ON
THURSDAY. SKIES WILL BE MOSTLY CLEAR...AND THERE WILL BE A STEADY
BUT VERY GRADUAL WARMING TREND THROUGH THE PERIOD...WITH HIGHS IN
THE IN THE MID TO UPPER 50S WEDNESDAY WARMING A CATEGORY PER
DAY...FINALLY REACHING THE MID TO UPPER 60S SATURDAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 150 AM SUNDAY...
MID LEVEL TROUGH MOVING SLOWLY EAST ACROSS CENTRAL NC AT 06Z. THE
CYCLONIC FLOW ASSOCIATED WITH THE FEATURE COUPLED WITH RESIDUAL
MOISTURE IN THE LOWEST 5000FT OF THE ATMOSPHERE MAINTAINING DECK OF
3000-5000FT CEILINGS OVER THE COASTAL PLAIN...SANDHILLS AND
EASTERN PIEDMONT. AS THE TROUGH MOVES EAST TOWARD THE COAST BY
09Z...W-NW FLOW BEHIND THE TROUGH WILL USHER DRIER AIR INTO THE
COLUMN...DISSIPATING THE CLOUD COVERAGE. THUS EXPECT CLEAR SKIES
OVER THE REGION BY 09Z. LIGHT NLY FLOW NEAR SURFACE EARLY THIS
MORNING WILL SLOWLY BACK TO A W-SW FLOW LATER TODAY.
VFR CONDITIONS EXPECTED TO PERSIST TONIGHT. A STRONG COLD FRONT WILL
CROSS THE AREA MONDAY. A THIN DECK OF CLOUD WITH BASES BETWEEN
4000-8000FT MAY ACCOMPANY THE FRONT BUT NO PRECIP SHOULD OCCUR. THE
PASSAGE OF THE FRONT WILL BE NOTED BUT A DEFINITE INCREASE IN THE
WINDS OUT OF THE NW WITH SUSTAINED SPEEDS 10-15KTS EXPECTED ACROSS
CENTRAL NC MONDAY AFTERNOON.
ASIDE FROM A FEW STRATOCU OVER THE REGION TUESDAY AFTERNOON WITH
BASES AROUND 4000FT...EXPECT MAINLY CLEAR SKIES ACROSS THE REGION
MONDAY NIGHT THROUGH THURSDAY AS STRONG COLD HIGH PRESSURE WILL
DOMINATE THE WEATHER PATTERN OVER THE SE U.S.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...DJF
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1044 AM CDT SUN OCT 26 2008
.UPDATE...WILL EXTEND HIGH WIND WARNING UNTIL 00Z FOR CENTRAL AND
SOUTHWEST. WILL LET HIGH WIND WARNING EXPIRE AT 21Z FOR NORTHWEST.
&&
.PREV DISCUSSION... /ISSUED 327 AM CDT SUN OCT 26 2008/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
A HIGH WIND WARNING IS THE SCREAMING MESSAGE IN TODAYS FORECAST.
TONIGHT THROUGH THE REST OF THE SHORT TERM...NO ISSUES TO MENTION AT
THIS TIME.
HAVE DECIDED TO UPGRADE THE CURRENT HIGH WIND WATCH TO A HIGH
WIND WARNING OVER ENTIRE FORECAST AREA...VALID FROM 9Z THROUGH
21Z. FULLY EXPECT AT SOME POINT DURING THE MID TO LATE AFTERNOON
THE HIGH WIND WARNING WILL BE REPLACED BY A WIND ADVISORY WHICH
WILL CONTINUE INTO THE EARLY EVENING HOURS.
THE REASONING BEHIND THIS IDEA FOLLOWS FROM THE PREVIOUS SHIFTS
KEY OBSERVATION OF WARMING ALOFT ABOVE THE H85 LAYER PER NAM/GFS
BUFR SOUNDINGS. THIS SAME TREND CONTINUED WITH THE 00Z RUN. IN
ESSENCE THIS WILL HELP DESTROY THE LINKAGE OF THE STRONG NW WINDS
FROM THE SFC UP THROUGH 600MB...WHICH IS WHAT WE ARE LOOKING AT IN
TERMS OF A MIXING DEPTH BETWEEN 12Z AND 17Z TODAY. FROM 17Z TO
21Z...THE TREND IN THE BUFR SOUNDINGS SHOW THE DEPTH OF THE MIXED
LAYER DECREASING OR SHRINKING. ESSENTIALLY THE STRONGEST WINDS
ALOFT WILL BECOME SEPARATED FROM THE WELL MIXED LAYER BELOW
RESULTING IN THE WINDS TO SHOW A WEAKENING TREND BELOW HIGH WIND
WARNING CRITERIA AFTER 21Z. THIS SUPPORTS THE IDEA THAT THE
HIGHEST PROBABILITY IN REACHING HIGH WIND WARNING CRITERIA WILL
OCCUR FROM THIS MORNING THROUGH THE EARLY AFTERNOON. SUSTAINED
WINDS OF 40 MPH OR HIGHER OR GUSTS TO 58 MPH DEFINE THE HIGH WIND
WARNING. CONFIDENCE IS HIGH THAT THIS WILL BE MET. IT WILL REMAIN
WINDY THROUGH LATE AFTERNOON...BUT WIND SPEEDS BY THIS TIME WILL
LIKELY BE MORE IN LINE WITH WIND ADVISORY CRITERIA THAN WARNING
CRITERIA. THE DAY SHIFT CAN RE-EVALUATE THIS LATER TODAY AND MAKE
THE FINAL CALL.
THE LATEST WATER VAPOR IMAGERY SHOWS THE UPSTREAM SHORTWAVE TROUGH
ULTIMATELY RESPONSIBLE FOR ENHANCING THE WINDS TODAY. IT IS CURRENTLY
LOCATED OVER WEST-CENTRAL SASKATCHEWAN AND MOVING SOUTHEAST WITH
TIME. A 160+ KT H30 JET IS ACCOMPANYING THE SHORTWAVE AND WILL
MIGRATE FROM NORTHWEST TO SOUTHEAST ACROSS OUR FORECAST AREA
BETWEEN 15Z AND 18Z TODAY. NOT A LOT OF VERTICAL MOTION/LIFT AS
DENOTED BY THE H85-H3 OMEGA FIELD. HOWEVER WILL CONTINUE WITH AN
ISOLATED SNOW SHOWER THREAT OVER OUR EASTERN ZONES TODAY. EXPECT
SUN AND CLOUDS VARYING FROM TIME TO TIME OVER THE FORECAST AREA
TODAY WITH MORE CLOUDS FAVORING THE EASTERN ZONES.
WINDS WILL DIMINISH TONIGHT TO AROUND 10KT AFTER MIDNIGHT WITH LOW
TEMPERATURES BY MONDAY MORNING IN THE SINGLE DIGITS ACROSS THE
WEST AND LOWER TO MID TEENS ELSEWHERE. AN APPROACHING RIDGE OF
HIGH PRESSURE WILL KEEP THE FORECAST AREA DRY FOR THE REST OF THE
SHORT TERM. DESPITE A CHILLY MONDAY WITH HIGHS ONLY IN THE UPPER
30S AND LOWER 40S...WARMING WILL QUICKLY KICK IN ON TUESDAY AS THE
RIDGE GETS CLOSER. HIGH TEMPERATURES WILL REACH BETWEEN 55F AND
65F TUESDAY AFTERNOON.
LONG TERM...WEDNESDAY THROUGH SUNDAY NIGHT
MAJOR RIDGING ACROSS THE NORTHERN PLAINS WILL MAINTAIN DRY WEATHER
AND ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM FORECAST PERIOD.
A COLD FRONT WILL DIP DOWN THURSDAY AFTERNOON AND THEN RETREAT
SATURDAY. NO PRECIPITATION IS EXPECTED WITH THIS FEATURE. ALL IN ALL
THE LONG TERM PROMISES NICE WEATHER.
AVIATION...
VERY STRONG NORTHWEST SURFACE WINDS TO 50 KNOTS WILL PRESENT A
HAZARD TO SMALLER AIRCRAFT ON TAKE OFF AND LANDING. EXPECT MODERATE
TO SEVERE TURBULENCE ALSO NEAR THE GROUND.
FIRE WEATHER...RED FLAG WARNING BEGINNING THIS MORNING THROUGH
THE AFTERNOON FOR PORTIONS OF THE WEST AND SOUTHWEST. SUSTAINED
NORTHWEST WINDS OF 35 TO 45 MPH AND GUSTS BETWEEN 50 AND 60 MPH
COMBINED WITH MINIMUM HUMIDITIES OF AROUND 25 TO 30 PERCENT WILL
CREATE CRITICAL FIRE WEATHER BEHAVIOR. RANGELAND FIRE DANGER INDICES
WILL ALSO BE IN THE VERY HIGH RANGE TODAY OVER THESE AREAS. PLEASE
REFER TO BISRFWBIS FOR FURTHER DETAILS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ003>005-011>013-018>023-025-031>037-040>048-050-051.
RED FLAG WARNING UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ017-018-031>033-040-041-043-044.
HIGH WIND WARNING UNTIL 4 PM CDT THIS AFTERNOON FOR NDZ001-002-
009-010-017.
&&
$$
WAA
AREA FORECAST DISCUSSION...CORRECTED
NWS BISMARCK ND
327 AM CDT SUN OCT 26 2008
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
A HIGH WIND WARNING IS THE SCREAMING MESSAGE IN TODAYS FORECAST.
TONIGHT THROUGH THE REST OF THE SHORT TERM...NO ISSUES TO MENTION AT
THIS TIME.
HAVE DECIDED TO UPGRADE THE CURRENT HIGH WIND WATCH TO A HIGH
WIND WARNING OVER ENTIRE FORECAST AREA...VALID FROM 9Z THROUGH
21Z. FULLY EXPECT AT SOME POINT DURING THE MID TO LATE AFTERNOON
THE HIGH WIND WARNING WILL BE REPLACED BY A WIND ADVISORY WHICH
WILL CONTINUE INTO THE EARLY EVENING HOURS.
THE REASONING BEHIND THIS IDEA FOLLOWS FROM THE PREVIOUS SHIFTS
KEY OBSERVATION OF WARMING ALOFT ABOVE THE H85 LAYER PER NAM/GFS
BUFR SOUNDINGS. THIS SAME TREND CONTINUED WITH THE 00Z RUN. IN
ESSENCE THIS WILL HELP DESTROY THE LINKAGE OF THE STRONG NW WINDS
FROM THE SFC UP THROUGH 600MB...WHICH IS WHAT WE ARE LOOKING AT IN
TERMS OF A MIXING DEPTH BETWEEN 12Z AND 17Z TODAY. FROM 17Z TO
21Z...THE TREND IN THE BUFR SOUNDINGS SHOW THE DEPTH OF THE MIXED
LAYER DECREASING OR SHRINKING. ESSENTIALLY THE STRONGEST WINDS
ALOFT WILL BECOME SEPARATED FROM THE WELL MIXED LAYER BELOW
RESULTING IN THE WINDS TO SHOW A WEAKENING TREND BELOW HIGH WIND
WARNING CRITERIA AFTER 21Z. THIS SUPPORTS THE IDEA THAT THE
HIGHEST PROBABILITY IN REACHING HIGH WIND WARNING CRITERIA WILL
OCCUR FROM THIS MORNING THROUGH THE EARLY AFTERNOON. SUSTAINED
WINDS OF 40 MPH OR HIGHER OR GUSTS TO 58 MPH DEFINE THE HIGH WIND
WARNING. CONFIDENCE IS HIGH THAT THIS WILL BE MET. IT WILL REMAIN
WINDY THROUGH LATE AFTERNOON...BUT WIND SPEEDS BY THIS TIME WILL
LIKELY BE MORE IN LINE WITH WIND ADVISORY CRITERIA THAN WARNING
CRITERIA. THE DAY SHIFT CAN RE-EVALUATE THIS LATER TODAY AND MAKE
THE FINAL CALL.
THE LATEST WATER VAPOR IMAGERY SHOWS THE UPSTREAM SHORTWAVE TROUGH
ULTIMATELY RESPONSIBLE FOR ENHANCING THE WINDS TODAY. IT IS CURRENTLY
LOCATED OVER WEST-CENTRAL SASKATCHEWAN AND MOVING SOUTHEAST WITH
TIME. A 160+ KT H30 JET IS ACCOMPANYING THE SHORTWAVE AND WILL
MIGRATE FROM NORTHWEST TO SOUTHEAST ACROSS OUR FORECAST AREA
BETWEEN 15Z AND 18Z TODAY. NOT A LOT OF VERTICAL MOTION/LIFT AS
DENOTED BY THE H85-H3 OMEGA FIELD. HOWEVER WILL CONTINUE WITH AN
ISOLATED SNOW SHOWER THREAT OVER OUR EASTERN ZONES TODAY. EXPECT
SUN AND CLOUDS VARYING FROM TIME TO TIME OVER THE FORECAST AREA
TODAY WITH MORE CLOUDS FAVORING THE EASTERN ZONES.
WINDS WILL DIMINISH TONIGHT TO AROUND 10KT AFTER MIDNIGHT WITH LOW
TEMPERATURES BY MONDAY MORNING IN THE SINGLE DIGITS ACROSS THE
WEST AND LOWER TO MID TEENS ELSEWHERE. AN APPROACHING RIDGE OF
HIGH PRESSURE WILL KEEP THE FORECAST AREA DRY FOR THE REST OF THE
SHORT TERM. DESPITE A CHILLY MONDAY WITH HIGHS ONLY IN THE UPPER
30S AND LOWER 40S...WARMING WILL QUICKLY KICK IN ON TUESDAY AS THE
RIDGE GETS CLOSER. HIGH TEMPERATURES WILL REACH BETWEEN 55F AND
65F TUESDAY AFTERNOON.
.LONG TERM...WEDNESDAY THROUGH SUNDAY NIGHT
MAJOR RIDGING ACROSS THE NORTHERN PLAINS WILL MAINTAIN DRY WEATHER
AND ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM FORECAST PERIOD.
A COLD FRONT WILL DIP DOWN THURSDAY AFTERNOON AND THEN RETREAT
SATURDAY. NO PRECIPITATION IS EXPECTED WITH THIS FEATURE. ALL IN ALL
THE LONG TERM PROMISES NICE WEATHER.
&&
.AVIATION...
VERY STRONG NORTHWEST SURFACE WINDS TO 50 KNOTS WILL PRESENT A
HAZARD TO SMALLER AIRCRAFT ON TAKE OFF AND LANDING. EXPECT MODERATE
TO SEVERE TURBULENCE ALSO NEAR THE GROUND.
&&
.FIRE WEATHER...RED FLAG WARNING BEGINNING THIS MORNING THROUGH
THE AFTERNOON FOR PORTIONS OF THE WEST AND SOUTHWEST. SUSTAINED
NORTHWEST WINDS OF 35 TO 45 MPH AND GUSTS BETWEEN 50 AND 60 MPH
COMBINED WITH MINIMUM HUMIDITIES OF AROUND 25 TO 30 PERCENT WILL
CREATE CRITICAL FIRE WEATHER BEHAVIOR. RANGELAND FIRE DANGER INDICES
WILL ALSO BE IN THE VERY HIGH RANGE TODAY OVER THESE AREAS. PLEASE
REFER TO BISRFWBIS FOR FURTHER DETAILS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING IN EFFECT UNTIL 4 PM CDT /3 PM MDT/ THIS AFTERNOON
FOR NDZ001>005-009>013-017>023-025- 031>037-040>048-050-051.
RED FLAG WARNING FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 7 PM
CDT /6 PM MDT/ THIS EVENING FOR NDZ017-018-031>033-040-041-043-
044.
&&
$$
KS/RSL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
230 AM CDT SUN OCT 26 2008
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
A HIGH WIND WARNING IS THE SCREAMING MESSAGE IN TODAYS FORECAST.
TONIGHT THROUGH THE REST OF THE SHORT TERM...NO ISSUES TO MENTION AT
THIS TIME.
HAVE DECIDED TO UPGRADE THE CURRENT HIGH WIND WATCH TO A HIGH
WIND WARNING OVER ENTIRE FORECAST AREA...VALID FROM 12Z THROUGH
21Z. FULLY EXPECT AT SOME POINT DURING THE MID TO LATE AFTERNOON
THE HIGH WIND WARNING WILL BE REPLACED BY A WIND ADVISORY WHICH
WILL CONTINUE INTO THE EARLY EVENING HOURS.
THE REASONING BEHIND THIS IDEA FOLLOWS FROM THE PREVIOUS SHIFTS
KEY OBSERVATION OF WARMING ALOFT ABOVE THE H85 LAYER PER NAM/GFS
BUFR SOUNDINGS. THIS SAME TREND CONTINUED WITH THE 00Z RUN. IN
ESSENCE THIS WILL HELP DESTROY THE LINKAGE OF THE STRONG NW WINDS
FROM THE SFC UP THROUGH 600MB...WHICH IS WHAT WE ARE LOOKING AT IN
TERMS OF A MIXING DEPTH BETWEEN 12Z AND 17Z TODAY. FROM 17Z TO
21Z...THE TREND IN THE BUFR SOUNDINGS SHOW THE DEPTH OF THE MIXED
LAYER DECREASING OR SHRINKING. ESSENTIALLY THE STRONGEST WINDS
ALOFT WILL BECOME SEPARATED FROM THE WELL MIXED LAYER BELOW
RESULTING IN THE WINDS TO SHOW A WEAKENING TREND BELOW HIGH WIND
WARNING CRITERIA AFTER 21Z. THIS SUPPORTS THE IDEA THAT THE
HIGHEST PROBABILITY IN REACHING HIGH WIND WARNING CRITERIA WILL
OCCUR FROM THIS MORNING THROUGH THE EARLY AFTERNOON. SUSTAINED
WINDS OF 40 MPH OR HIGHER OR GUSTS TO 58 MPH DEFINE THE HIGH WIND
WARNING. CONFIDENCE IS HIGH THAT THIS WILL BE MET. IT WILL REMAIN
WINDY THROUGH LATE AFTERNOON...BUT WIND SPEEDS BY THIS TIME WILL
LIKELY BE MORE IN LINE WITH WIND ADVISORY CRITERIA THAN WARNING
CRITERIA. THE DAY SHIFT CAN RE-EVALUATE THIS LATER TODAY AND MAKE
THE FINAL CALL.
THE LATEST WATER VAPOR IMAGERY SHOWS THE UPSTREAM SHORTWAVE TROUGH
ULTIMATELY RESPONSIBLE FOR ENHANCING THE WINDS TODAY. IT IS CURRENTLY
LOCATED OVER WEST-CENTRAL SASKATCHEWAN AND MOVING SOUTHEAST WITH
TIME. A 160+ KT H30 JET IS ACCOMPANYING THE SHORTWAVE AND WILL
MIGRATE FROM NORTHWEST TO SOUTHEAST ACROSS OUR FORECAST AREA
BETWEEN 15Z AND 18Z TODAY. NOT A LOT OF VERTICAL MOTION/LIFT AS
DENOTED BY THE H85-H3 OMEGA FIELD. HOWEVER WILL CONTINUE WITH AN
ISOLATED SNOW SHOWER THREAT OVER OUR EASTERN ZONES TODAY. EXPECT
SUN AND CLOUDS VARYING FROM TIME TO TIME OVER THE FORECAST AREA
TODAY WITH MORE CLOUDS FAVORING THE EASTERN ZONES.
WINDS WILL DIMINISH TONIGHT TO AROUND 10KT AFTER MIDNIGHT WITH LOW
TEMPERATURES BY MONDAY MORNING IN THE SINGLE DIGITS ACROSS THE
WEST AND LOWER TO MID TEENS ELSEWHERE. AN APPROACHING RIDGE OF
HIGH PRESSURE WILL KEEP THE FORECAST AREA DRY FOR THE REST OF THE
SHORT TERM. DESPITE A CHILLY MONDAY WITH HIGHS ONLY IN THE UPPER
30S AND LOWER 40S...WARMING WILL QUICKLY KICK IN ON TUESDAY AS THE
RIDGE GETS CLOSER. HIGH TEMPERATURES WILL REACH BETWEEN 55F AND
65F TUESDAY AFTERNOON.
.LONG TERM...WEDNESDAY THROUGH SUNDAY NIGHT
MAJOR RIDGING ACROSS THE NORTHERN PLAINS WILL MAINTAIN DRY WEATHER
AND ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM FORECAST PERIOD.
A COLD FRONT WILL DIP DOWN THURSDAY AFTERNOON AND THEN RETREAT
SATURDAY. NO PRECIPITATION IS EXPECTED WITH THIS FEATURE. ALL IN ALL
THE LONG TERM PROMISES NICE WEATHER.
&&
.AVIATION...
VERY STRONG NORTHWEST SURFACE WINDS TO 50 KNOTS WILL PRESENT A
HAZARD TO SMALLER AIRCRAFT ON TAKE OFF AND LANDING. EXPECT MODERATE
TO SEVERE TURBULENCE ALSO NEAR THE GROUND.
&&
.FIRE WEATHER...RED FLAG WARNING BEGINNING THIS MORNING THROUGH
THE AFTERNOON FOR PORTIONS OF THE WEST AND SOUTHWEST. SUSTAINED
NORTHWEST WINDS OF 35 TO 45 MPH AND GUSTS BETWEEN 50 AND 60 MPH
COMBINED WITH MINIMUM HUMIDITIES OF AROUND 25 TO 30 PERCENT WILL
CREATE CRITICAL FIRE WEATHER BEHAVIOR. RANGELAND FIRE DANGER INDICES
WILL ALSO BE IN THE VERY HIGH RANGE TODAY OVER THESE AREAS. PLEASE
REFER TO BISRFWBIS FOR FURTHER DETAILS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING FROM 7 AM CDT /6 AM MDT/ THIS MORNING TO 4 PM
CDT /3 PM MDT/ THIS AFTERNOON FOR NDZ001>005-009>013-017>023-025-
031>037-040>048-050-051.
RED FLAG WARNING FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 7 PM
CDT /6 PM MDT/ THIS EVENING FOR NDZ017-018-031>033-040-041-043-
044.
&&
$$
KS/RSL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
111 PM EDT MON OCT 27 2008
.SYNOPSIS...
A SERIES OF WEAK DISTURBANCES EMBEDDED IN NORTHWEST FLOW ALOFT
WILL BRING SEVERAL DAYS OF UNSEASONABLY COOL TEMPERATURES AND THE
SEASON`S FIRST LAKE EFFECT SNOWS. FAIR WEATHER AND MODERATING
TEMPERATURES WILL RETURN LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS IN NRN AND WRN MTS CONTINUE TO DWINDLE AS THEY TRY TO
MOVE TO THE EAST. COLD FRONTAL TROF SLOWLY EXITING THE SUSQ
VALLEY...BUT THE COLD AIR TRAILING BEHIND A BIT IN W PA.
WATER VAPOR SHOWS A POTENT SHORT WAVE MOVING THRU OHIO...WHICH
PROMISES TO HELP FIRE UP THE LAKE EFFECT MACHINE OVER THE NEXT
COUPLE OF DAYS AS INCREASINGLY CHILLY AIR POURS INTO THE REGION.
FOR TODAY CLOUDS INCREASING FROM THE WEST AS THE CYCLONIC
FLOW...COLD ADVECTION AND LOW LEVEL MOISTURE MAKE THEIR PRESENCE
FELT. MODELS AGREE THE BEST CHANCE OF PRECIP TODAY WILL BE
OROGRAPHIC AND LAKE ENHANCED...MEANING WESTERN AND NORTHER HIGH
TERRAIN WILL STAND THE BEST CHANCE OF SEEING SHOWERS. HAVE ALSO
KEPT WORDING FOR AN ISOLATED THUNDERSTORM TODAY JUST IN THE NW
MTNS AS THE VERY COLD AIR ALOFT ACCOMPANYING THE SHORTWAVE WILL
WORK TO SHARPLY DECEASE STABILITY. PROGGED MID LEVEL LAPSE RATES
EXCEED 7C/KM BY AFTERNOON...WITH LI`S APPROACHING ZERO AND
T-TOTALS NEARING 60. WE WILL BE FAIRLY DRY OVERALL...BUT WITH SO
MUCH COLD AIR ALOFT POURING IN...SOME OF THE SHOWERS WILL HAVE THE
POTENTIAL MAKE FOR A FEW RUMBLES OF THUNDER AND PERHAPS SOME SMALL
HAIL/GRAUPEL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
SIGNIFICANT DIFFERENCES ARISE EARLY ON IN THE MODEL GUIDANCE WITH
THE NAM WANTING TO BRUSH MY FAR EASTERN COUNTIES WITH SOME SIG
PRECIP ASSOCIATED WITH EVENTUAL OFFSHORE DEVELOPMENTS ASSOCIATED
WITH OUR DEEPENING UPPER AIR LOW/TROF. WHILE MOST GUIDANCE AGREES
WE SEE SOME SORT OF DEVELOPMENT ALONG OR JUST OFF THE EASTERN
SEABOARD...THE 00Z NAM IS THE OUTLIER BRINGING SO MUCH PRECIP SO
FAR WEST NEAR MY FCST AREA. 00Z GEFS AND 21Z SREF SUGGEST LOW TO
NO POPS IN THE EAST WHILE THE OPERATIONAL MODELS KEEP THE BEST LOW
LEVEL MOISTURE FLUX AND PWAT ANOMALIES REMAIN WELL OFFSHORE. DID
COMPROMISE A TAD ON THE FAR EASTERN CHANCES FOR RAIN TUESDAY...TO
BETTER BLEND WITH EASTERN NEIGHBORS...BUT BELIEVE THE CHANCES FOR
PRECIP WILL BE VERY LOW OVERALL.
THE MAIN ACTION SHOULD STAY IN THE WEST AND NW WHERE PREVIOUSLY
MENTIONED OROGRAPHIC AND LAKE EFFECT FORCES MANAGE TO BRING THE
HIGHEST CHANCES FOR PRECIP. THINK THE SEASON`S FIRST ACCUMULATING
SNOWS WILL BE SEEN IN THE USUAL SNOW BELT AREAS...BUT WITH
MARGINAL SURFACE TEMPS AND RELATIVELY SHORT OVER-LAKE WIND
FETCHES...HAVE KEPT THE MENTION OF ACCUMULATIONS ON THE LIGHT
SIDE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
WE MAY SEE A WINDOW OF OPPORTUNITY FOR SLIGHTLY HEAVIER LAKE
EFFECT TUESDAY NIGHT INTO WED AS GUIDANCE SUGGESTS A BETTER OVER-
LAKE FETCH AND A POSSIBLE LAKE HURON CONNECTION. STILL TOO EARLY TO
ZERO IN ON WHAT WOULD BE A MESO SCALE FEATURE...JUST SOMETHING TO
CONSIDER FOR THE MEDIUM RANGE.
BIGGER PATTERN WILL KEEP US COLDER THAN NORMAL FOR THE NEXT
SEVERAL DAYS...BEFORE SOME MODERATING TEMPS MAKE A RETURN LATER
IN THE WEEK. OTHER THAN WRESTLING WITH LAKE/OROGRAPHIC
SHOWERS...PRECIP WILL NOT BE A BIG CONCERN.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
FIRST BAND OF SHOWERS MADE IT AS FAR EAST AS THE OFFICE OVERNIGHT.
A FEW SPOTS HAD MVFR CONDITIONS FOR A BRIEF TIME.
MOST OF TODAY WILL BE VFR...BEFORE SECONDARY FRONT MOVES IN
LATE.
HAD SOME THUNDERSTORMS OVER LAKE ERIE EARLIER...ONLY THE SECOND
TIME I HAVE SEEN LAKE EFFECT STORMS THAT FAR FROM THE RADAR SINCE
THE OFFICE WAS OPEN. LAST TIME WAS 2 YEARS AGO.
WHILE WINDS ALOFT ARE ON THE STRONG SIDE...WINDS AT LOW LEVELS WILL
NOT REALLY PICK UP MUCH TODAY. WINDS INCREASE AFTER 06Z TONIGHT...
ONCE THE UPPER LEVEL TROUGH GOES BY. WITH SUCH STRONG WINDS...
WOULD NOT BE SURPRISE TO SEE REPORTS OF SEVERE TURB. FROM THE
LARGER AIRCRAFT TODAY.
CURRENT AREA OF SHOWERS FALLING APART...AS WINDS BACK MORE...
AND FRONT STALLS ACROSS THE MTNS.
LATE TONIGHT...COASTAL DEVELOPS AND WINDS PICK UP...AND
CONDITIONS BECOME MORE MVFR WITH SOME IFR CONDITIONS. MOST SPOTS
WILL HAVE RAIN FOR PCPN TYPE...BUT SOME SNOW WILL BE POSSIBLE
AFTER 08Z.
SOME LAKE EFFECT RAIN AND SNOW SHOWERS ON TUE...BUT WILL BE
LIMITED...AS TEMPS WILL BE MARGINAL FOR SNOW...AND WINDS WILL
FAVOR MULTIPLE BANDS.
INCREASING CONCERN OVER COASTAL LOW...SYSTEM LIKELY TO DEEPEN
FAST...AS JET ROUNDS BASE OF TROUGH...AND WINDS AT 500 MB MAY
EXCEED 100 KNOTS. SHOULD SYSTEM CUT OFF MUCH FURTHER TO THE
SOUTH AND WEST...HEAVY WET SNOW MAY BECOME A PROBLEM FOR AREAS
JUST TO THE EAST OF IPT. OCT 1987 AND OCT 1993 HAD A SIMILAR
EVENTS.
IMPROVING CONDITIONS LATER WED INTO FRIDAY...AS A LARGE SCALE
WARM UP OCCURS. SHOULD BE VFR CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LACORTE/RXR
NEAR TERM...LACORTE/RXR
SHORT TERM...LACORTE
LONG TERM...LACORTE
AVIATION...MARTIN
|