WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
200 PM MST THU DEC 2 1999
APPROACHING PACIFIC TROUGH BEING HANDLED A LITTLE DIFFERENTLY
BETWEEN MODELS. DIFFERENCES NOT MUCH FOR NORTHERN ZONES BUT COULD
BE SIGNIFICANT FOR SOUTHERN ZONES AND SOME CENTRAL ZONES. ETA AGAIN
IS TAKING THE VORT FURTHEST SOUTH...WHILE NGM AS IS USUALLY THE
CASE IS THE MOST ABUNDANT WITH MOISTURE OVER OUR ENTIRE CWFA. ETA
AND RUC SEEM TO BE DOING BEST JOB DELINEATING THE DOUBLE
STRUCTURED NATURE OF THE MID LEVEL RH PATTERN. RUC AND NGM TAKE
THE 80% PLUS RH TO THE NM BORDER. WOULD EXPECT THE RUC MODEL...
WHICH IS ONLY AVAILABLE THROUGH FRI MORNING...TO VERIFY THE
BEST THRU FRI MORNING. ALREADY BEGAN SNOWING IN NRN WASATCH
MOUNTAINS OF UT BY NOON...AND EXPECT TIMING OF SNOW ONSET IN ERN
UT/WRN CO TONIGHT TO BE CLOSE TO PREVIOUS FCST PACKAGE. LOW LEVEL
WINDS UP TO ABOUT H6 BECOME NORTHERLY BY MID MORNING ON ALL MODELS...
WHICH SHOULD SHUT OFF THE SNOW IN MOST NRN AND CNTRL AREAS EXCEPT FOR
THE FEW OROGRAPHICALLY FAVORED LOCATIONS. LOW CIRCULATION WHICH
MODELS DEPICT IN THE SRN CO/NRN NM BORDER AREA FRI MORNING MAY KEEP
SNOW SHOWERS GOING IN SW MOUNTAIN AREAS THROUGHOUT THE DAY...THOUGH
LIMITED MOISTURE AVAILABILITY LIKELY TO LIMIT ACCUMULATIONS TO SNOW
ADVISORY CRITERIA IN WESTERN SAN JUAN MTNS. ONLY CAVEAT FOR SW CO
MTNS IS IF NGM MOISTURE FIELD WERE TO VERIFY...WHICH IS NOT LIKELY...
WHICH WOULD PRODUCE MORE SNOW THAN PRESENTLY EXPECTED. SNOW ADVISORY
SEEMS TO BE APPROPRIATE HIGHLIGHT FOR MOST WESTERN CO MOUNTAINS LATE
TONIGHT AND FRIDAY. SNOW MODEL INDICATES 4-8 INCHES IN GENERAL OVER
THE 18 HOUR PERIOD IN QUESTION...MIDNIGHT TONIGHT THROUGH FRI
AFTERNOON. MOST OF THE SNOW IN NRN/CNTRL MTNS SHOULD BE BETWEEN
MIDNIGHT TNGT AND MID MORNING FRI. MOST OF SNOW IN SW CO MTNS SHOULD
BE VERY LATE TONIGHT THROUGH FRI AFTERNOON. HAVE SOME DOUBTS ABOUT
INCLUDING C0Z012...CRESTED BUTTE/TAYLOR PARK AREAS...IN THE SNOW
ADVISORY SINCE AMOUNTS WILL LIKELY BE ON THE LOW SIDE ESPECIALLY IF
ETA MODEL VERIFIES. EXCLUDED ERN UT MTNS AND LOWER MOUNTAINS OF WRN
CO...COZ003-017...FROM THE SNOW ADVISORY DUE TO EXPECTED SNOWFALL
BEING EITHER BELOW CRITERIA OR BARELY BORDERLINE FOR ADVISORY
CRITERIA. ALSO CONTEMPLATED ADDING BLOWING SNOW TO THE ADVISORY...
HOWEVER BELIEVE THIS SITUATION TO BE LOCALIZED.
DRY WX TO PREVAIL DURING WEEKEND AND INTO FIRST FEW DAYS OF NEXT
WEEK. AGREE WITH PREVIOUS FORECASTER THAT THE WEAK HIGH PRESSURE
ALOFT OVER OUR AREA DURING THAT PERIOD WILL BE CONDUCIVE TO
OVERRUNNING MOISTURE...MAINLY HIGH LEVEL CLOUDS AT TIMES OVER THE
AREA WITH NO PRECIP. TEMPS IN VALLEYS LIKELY WILL STRUGGLE TO
RECOVER DUE TO INVERSIONS...AND THUS HAVE KEPT TEMPS ON CHILLY SIDE
AFTER THIS PACIFIC SYSTEM MOVES EAST. SUNDAY MORNING MAY HAVE SOME OF
THE COLDEST TEMPERATURES SO FAR THIS WINTER.
PRINGLE
.GJT...SNOW ADVISORY LATE TONIGHT & FRIDAY...COZ004-009>012-018-019.
FXUS65 KPUB 022133 co
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHICAGO IL
830 PM CST THU DEC 2 1999
ALTHOUGH WINDS ARE DROPPING OFF A BIT IN FAR NORTHWEST CWA, CLOUDY
SKIES AND GOOD NEUTRAL TO WEAK WARM ADVECTION ON BOUNDARY LAYER
SHOULD HOLD TEMPS WELL ABOVE MINS FORECAST IN AFTERNOON ZONES. ONLY
FAR NORTHWEST ZONES LIKELY TO HAVE A SHOT AT UNDER 50. LATEST RUC
295K ANALYSIS AND FORECAST STILL SUGGESTING RAIN A GOOD POSSIBILITY
LATE (WELL AFTER MIDNIGHT) SO NO BIG CHANGE TO THE PRECIP FORECAST
IN UPCOMING ZONE AMENDMENTS. PRECIP AREA NOW BLOSSOMING IN
OKLAHOMA/KANSAS/ARKANSAS LIKELY TO EXPAND RAPIDLY NORTHEAST.
KAPLAN
FXUS63 KLOT 022126 il
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
944 AM EST THU DEC 2 1999
SYNOPSIS:
LOW PRESSURE SOUTH OF NOVA SCOTIA WILL WEAKEN AS IT DRIFTS EAST AWAY
FROM THE REGION. A NARROW RIDGE OF HIGH PRESSURE WILL BUILD ACROSS
THE REGION LATER TODAY THROUGH FRIDAY. A WEAK COLD FRONT WILL MOVE
ACROSS THE AREA FRIDAY NIGHT.
TECHNICAL DISCUSSION:
LATEST IR SATL IMAGERY SHOWED INTENSE LOW NR NS W/SIGNS OF
RETROGRADING TO THE W. BACK EDGE OF SCU/AC SHIELD ACRS ZNS 5>30.
FURTHER N & W...SCT AC & CI FM QUEBEC PROV. LATEST RUC2 HAS LLVL RH
BACKING INTO ZNS 5-6 & THRU DOWNEAST THIS AFTN. MTRS OVER IN NEW
BRUNSWICK SHOWING -SN. IF SYSM BACKS FAR ENUF W...I WOULDN/T RULE OUT
SOME SHSN/-SN ESP ZNS 2>6. AM CONSIDERING THROWING IN THE MENTION OF
A FLURRY OR SHSN. WILL DECIDE AFT ASSESSING THGS A BIT MORE.
FOR TEMPS...AM TOYING W/THE IDEA OF SHAVING MAXS BACK A NOTCH DUE
TO N WIND & INCG CLDS ESP ERN & DOWNEAST ZNS.
MARINE: PER TELCO W/GYX...AGREE TO LEAVE GLW AS IS. BOUYS STILL
CLOSE TO GALES. SUNSHINE & LOW NOT MOVG MUCH WILL KEEP GRDNT TIGHT.
WE BELIEVE WINDS WILL CONT IN THAT 30-35 KT RNG THRU 21Z.
.CAR...GLW.
JAH
me
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1000 AM EST THU DEC 2 1999
QUIET WEATHER EXPECTED FOR THE AFTERNOON.. AS 06Z ETA AND 12Z RUC
INDICATE SURFACE HIGH REMAINING IN PLACE AS UPPER LEVEL RIDGE BUILDS
INTO THE AREA. SOME HIGH CLOUDINESS SPILLING OVER THE TOP OF THE
RIDGE.. SO WILL CONTINUE WITH MSUNNY FORECAST AS OPPOSED TO SUNNY.
TEMPS HAVE RECOVERED A LITTLE BIT OVER THE PAST COUPLE OF HOURS.. AND
ARE RUNNING AT OR SLIGHTLY ABOVE MOS 3-HOURLY GUIDANCE. TEMPS UPSTREAM
YESTERDAY WERE MAINLY IN THE 40S.. BUT DOWNSLOPE FLOW ACROSS THE AREA
MAY PUSH THOSE READINGS UP A COUPLE OF DEGREES FOR US TODAY. 14Z LAMP
GUIDANCE SHOWING HIGHS AROUND 50 FOR AREAS WEST OF THE BLUE RIDGE.. AND
UPPER 40S FOR BALTIMORE AND WASHINGTON. MAY TWEAK AFTERNOON MAX TEMPS
UP A DEGREE OR TWO.. BUT FOR THE MOST PART GOING FORECAST LOOKS GOOD.
.LWX...NONE.
MARGRAF!
md
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
955 PM EST THU DEC 02 1999
LATEST SFC CHART SHOWS CWA IN LGT SELY FLOW AHD OF LO PRES OVR SW MN
AND ITS ATTENDANT WARM FNT XTNDG ESEWD THRU SRN WI TO NW OH.
ALTHOUGH SFC DWPTS IN COOL AIR OVR CWA/NRN WI AND LWR MI AHD OF WARM
FNT REMAIN MAINLY 25 TO 35...DWPTS RISING INTO 40S IN WARM SECTOR
OVR SRN WI AND IL. ALSO SOME LK MI MSTR ENHANCEMENT IN SELY FLOW HAS
RESULTED IN PTCHY LO CLD ACRS ECNTRL ZNS WITH VFR VRBL IFR CIG AT
KSAW ARND 00Z A BIT PROBLEMATIC FOR TAF. MN SFC LO ASSOCIATED WITH
SHRTWV TROF NOW ENTERING NW MN IN WSWLY SPLIT FLOW ALF ON WRN FLANK
OF BLDG UPR RDG IN E PER WV LOOP/00Z H5 RAOBS. IR SAT LOOP SHOWS
COMMA CLD HEAD OVR NRN MN SHIFTING NEWD WITH RADAR COMPOSITE/SFC OBS
INDICATING PTCHY LGT SN WHERE MODELS FCSTG H85-5 QVECTOR CNVGC.
HOWEVER SWLY FLOW IN DRY SLOT AHD OF SHRTWV HAS ADVCTD DRIER AIR ALF
OVR CWA...AND UPSTREAM 00Z MPX/GRB RAOBS SHOW A RELATIVELY DRY
PROFILE. SO JUST LOTS OF SC OVR FA WITH NO PCPN.
MAIN FCST CONCERNS TNGT ARE POTENTIAL FOR PCPN/FOG AND TEMPS. MODELS
INDICATE MN SHRTWV/LO PRES WL CONT TO ENE TNGT WITH SFC WARM FNT
APRCHG MNM TOWARD 12Z. 12Z MODELS/18Z MESOETA CONTINUED ON EARLIER
TREND OF TRYING TO MOISTEN ATMOSPHERE TOO QUICKLY AND WERE TOO QUICK
TO GENERATE PCPN OVR SE ZNS BEGINNING ARND 00Z. GRB PROFILE
INDICATES ATMOSPHERE REMAINS PROHIBITIVELY DRY. ALTHOUGH INCRSG LO
LVL MSTR S OF WARM FNT WL OVRRUN COOLER AIR MASS TO N AND RESULT IN
STEADY BUT GRDL INCRS IN LO-MID TROP RH OVR NE WI/SE ZNS/NRN LK MI
AS DEPICTED ON I295 ISENTROPIC SFC FCSTS...GRB SDNG SUGS A LOT OF
MOISTENING STILL NECESSARY. SO PREFER 00Z RUC FCST...WHICH SHOWS LGT
RA DVLPG THIS EVNG OVR WI AND SPRDG TOWARD MNM ARND 12Z. ALTHOUGH
H85-5 QVECTOR CNVGC ASSOCIATED WITH MN SHRTWV WL MOVE INTO WRN ZNS
LATE THIS EVNG/OVRNGT...ATMOSPHERE THERE SHUD REMAIN PROHIBITIVELY
DRY WITH BEST MSTR ADVCTN REMAINING TO E.
EVEN THOUGH LO-MID TROP SHUD REMAIN TOO DRY FOR RA...HIER SFC DWPTS
IN SELY FLOW OFF LK MI SUG POTENTIAL FOR FOG/DZ...MAINLY IN DOWNWIND
AREAS FM ESC-ISQ. HOWEVER...FAIRLY DRY LO LVLS OBSVD ON OTHR SIDE OF
LK MI WL PREVENT ANY DENSE FOG. ALTHOUGH LO LVL MSTR IMPACTING SAW
ATTM...FCST VEERING OF LO LVL WND TO MORE SSWLY OVRNGT AS SFC LO
HEADS TO NW WL CUTOFF LK MI MOISTENING IN CNTRL ZNS. ABUNDANT LO CLD
AND GENERAL WAD WL PREVENT TEMPS FM FALLING MORE THAN A FEW DEGREES
FM CURRENT READINGS. IN FACT...LATEST LAMP GUIDANCE INDICATES TEMPS
WL REMAIN STEADY.
WL UPDATE ZNS TO GO LESS PESSIMISTIC WITH FOG/DZ XCPT OVR ERN ZNS.
.MQT...NONE.
KC
FXUS63 KDTX 030244 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
844 PM CST THU DEC 2 1999
PLENTY OF LOW CLOUDINESS COVERING THE CWA THIS EVENING WITH A WEAK
LOW PRESSURE CENTER IN THE SOUTHERN PART OF MN. THINGS SHOULD REMAIN
ABOUT THE SAME FOR THE BALANCE OF THE NIGHT. MAIN UPPER LEVEL ENERGY
IS TO THE NORTH AND SOUTH OF US OVERNIGHT. FIRST SHORT WAVE IS OVER
FAR NORTHERN MN AT THIS TIME AND SOME LIGHT PRECIPITATION IS
OCCURRING. THIS FEATURE IS PROGGED TO CONTINUE MOVING SLOWLY
EASTWARD THROUGH THE NIGHT. SECOND SHORT WAVE IS OVER THE SOUTHERN
PLAINS AND WILL BE MOVING INTO MO BY DAYBREAK. QUITE IMPRESSIVE
DESTABILIZATION TAKING PLACE OVERNIGHT OFF TO OUR SOUTH ACROSS IA
AND MO WITH RUC H8 LI/S -2 TO -4 AND H8-H5 LAPSE RATES >6 DEG C.
WILL KEEP THE SMALL CHANCE OF RAIN FOR THE FAR SOUTHEAST PART OF THE
CWA FOR LATE TONIGHT BUT REMOVE DRIZZLE WORDING ELSEWHERE. WILL KEEP
THE MENTION OF FOG...ESPECIALLY IN THE FAR WESTERN PART OF MN. WILL
RAISE LOWS A FEW DEGREES IN THE NORTH AND FROM 5 TO 10 DEGREES IN
SOUTHERN MN WHERE DEW POINTS ARE IN THE UPPER 30S.
.MSP...NONE.
HILTBRAND
FXUS63 KDLH 022133 mn
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1000 PM CST THU DEC 2 1999
SATELLITE LOOPS INDICATING STORM SYSTEM OVER THE PLAINS GETTING ITS
ACT TOGETHER WITH STORMS OVER NRN TX/OK/WRN AR. AHEAD OF THIS SYSTEM...
STRONG 35-45KT LLJ OVER ARK-LA-TEX REGION LENDING TO GOOD LOW LEVEL
MOISTURE TRANSPORT OFF THE WRN GULF OF MEXICO IN INCREASING SLY FLOW.
ENHANCEMENT OF MID/HIGH LEVEL MOISTURE ALSO APPROACHING SLOWLY FROM
THE WEST IN VICINITY OF 80-100KT 300 MB JET MAX OVER NE TX. ALL
TOLD...CURRENT FORECAST HANDLES OVERALL SCENARIO WELL ON WINDS/TEMPS/
POPS AS MAIN UPPER SUPPORT WITH THIS FIRST SYSTEM SHEARS JUST TO THE
NW OF THE FA PER LATEST RUC DATA. WILL UPDATE MAINLY FOR TEMPORAL
WORDING AND MAY JUMP LOWS UP A HALF CAT OR SO IN PARTS OF THE NORTH
AND WEST WITH CLOUD COVER/WINDS INCREASING. OTHERWISE...NOTHING ELSE
TO ADD.
JAN 52/72/57/72 2433
MEI 45/74/55/72 -333
.JAN...
MS...NONE.
AR...NONE.
LA...NONE.
05
FXUS64 KJAN 022113 ms
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
900 PM MST THU DEC 2 1999
MAJOR PROBLEMS WITH THE FORECAST. SATELLITE PICTURES SHOW THAT THE TOPS
ARE WARMING IN IDAHO WITH SNOW AND CLOUDS DECREASING FROM
OBSERVATIONS...SUCH AS KMYL AND KSMN. TFX AND OTHER RADARS SHOWING
ECHOES WEAKENING. MAIN VORTICITY MAXIMUM IS DIGGING WAY SOUTH OF MONTANA
AND VORTICITY MAXIMUM THAT IS SUPPOSE TO BE IN NORTHERN BRANCH OF SPLIT
IN SOUTHWEST MONTANA LATE TONIGHT ON OLD PROGS IS NO LONGER PROGGED INTO
AREA ON NEW RUC...NGM AND ETA. THE VORTICITY IS MAINLY SHEAR VORTICITY
IN WESTERN MONTANA AND MOVES LITTLE. QPF ON NEW PROGS IS QUITE LOW ALSO.
DOWNSLOPE FLOW EAST OF DIVIDE NOT HELPING...BUT IT WILL PROBABLY GO TO
NORTHWESTERLY UPSLOPE FRIDAY WHEN DYNAMICS ABOUT OVER IN SPLIT FLOW AND
LOSS OF SOUTHERLY MOISTURE FEED. WILL UPDATE ZONES AND STATE FORECAST
AND DROP ALL HIGHLIGHTS. OARD
GTF 3400 HLN 5500 HVR 4410
FXUS65 KMSO 030340 mt
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
250 PM CST THU DEC 2 1999
MAJOR FCST CONCERNS DEAL WITH PSBL EXTENT OF LOW CLDS/F TNGT AND THEN
SECOND UPR SYSTEM WHICH WL BEGIN TO AFFECT FCST AREA SATURDAY BUT
MAINLY SATURDAY NIGHT/EARLY SUNDAY. MODELS ARE FAIRLY CLOSE IN
SHORT TERM...BUT DIVERGE RTHR SIGFNTLY BY 48HRS. LAST NGTS ETA WAS
PRBLY A LTL BTR WITH SPEED/STRENGTH OF 2ND UPR TROF WHICH CURRENT
STLT SHOWD IT MOVG INTO FAR NWRN NV. ETA IS SLOWER AND MUCH FTHR S
WITH THE UPR SYS AND ASSOCD SFC LOW BY 48HRS. WITH 140+ KT JET AT
250 MB STILL DIVING DOWN BACK SIDE OF THE TROF THIS SOLUTION CAN NOT
BE TOTALLY RULED OUT. THIS WOULD POINT TO MORE COLD AIR OVER
SPREADING FCST AREA WITH ANY PCPN CHANGING TO SNOW QUICKER BUT LESS
OF IT. FOR NOW WL USE BLEND OF ALL MODELS AND BRING MODESTLY HIGH
POPS INTO AREA SATURDAY BUT WON/T CHANGE TO FROZEN PCPN SERN ZONES.
IN SHORT TERM...VISIBLE STLT HAS SHOWN A FASTER DECREASE/SWD SHIFT
IN LOW CLDS LAST HR OR SO AIDED BY ADVCTN OF SLIGHTLY DRIER AIR AND
MODERATE NW WNDS FAR NWRN CWA. HOWEVER...LATEST RUC 925 MB FCST NOW
BACKS LOW LVL WINDS TO THE SW BY 06Z AS FAR NW AS OLU AND OFK.
DON/T KNOW IF THIS WILL QUITE VERIFY...BUT IT DOES MAKE LGT WINDS
LOOK LIKELY MUCH OF CWA OVERNIGHT. WITH DWPTS RANGING FM UPPER 30S
NW TO NEAR 50 SOUTH...LOW CLDS AND FOG LOOK QUITE PSBL. WL KEEP
DRIZZLE SERN ZONES CLOSER TO THE CYCLONIC LOW LVL FLOW. ALSO WITH
FIRST UPR SYS...ALTHOUGH IT WL STAY TO OUR S...SPRDG UPR DIVERGENCE
OVR SERN ZONES AND SOME ISENTROPIC LIFT ARND 295-300 K SFCS...WL
KEEP POPS IN FCST THERE. WL CUT BACK TO SLIGHT CHC CATEGORY LNK/OMA
AREAS. 850 MB JET ALSO FAIRLY IMPRESSIVE...AND ALTHOUGH IT STAYS
MAINLY TO OUR SE SOME ELEVATED CONVECTION PSBL SERN CORNER TNGT AS
850 MB BASED LIFTED FM AVN GOES NEGATIVE. RELATIVELY HIGH DWPTS AND
EXPECTED CLOUD DEVELOPMENT MAKES FWC TEMPS LOOK TOO COOL TNGT.
WL CONT CLDS/F AND PSBL DRIZZLE IN MORNING FRIDAY WITH CHC OF
SHOWERS SERN ZONES. COULD BE SOME AFTN BREAKS IN OVC BFR NEXT SYS
ARRIVES...SPCLY IF LOW CLDS/F NOT AS EXTENSIVE AS EXPECTED. FOR NOW
WL LEAVE ALL BUT NWRN ZONES MOCLDY ALL DAY...WL ALLOW FOR SOME
SUNSHINE NW IN THE AFTN. NO AFTN POPS ATTM WITH HIGHS NEAR PREV
FCST/FWC VALUES.
QG FORCING/ISENTROPIC LIFT BEGINS INCREASING FM SWRN TOWARD NERN
NEBR BY SAT MORNING AS NEXT SYS CROSSES SRN RCKYS. WL INTRODUCE CHC
LGT PCPN NERN NEBR BY SAT MORNING SPRDG ACRS CWA DURING SATURDAY.
THERE COULD BE A FIRST WAVE OF WRM ADVCTN PCPN DRIVEN BY ISENTROPIC
LIFT WHICH COULD DECREASE LATER SAT BFR MAIN DYNAMICS LIFT OUT SAT
NGT/SUN. SO IT PRBLY WON/T BE AN ALL DAY PCPN EVENT SAT MOST AREAS
WITH PCPN AMOUNTS...IF ANY...STILL FAIRLY LIGHT. THIS COULD CHANGE
IN EXTENDED...SPCLY IF SYS LIFTS FTHR NWWD PER AVN. WE WILL HANDLE
THIS BY ADDING A SAT NGT PD TO EXTENDED MENTIONING JUST SNOW NERN
ZONES...RAIN CHANGING TO SNOW FM LNK TO OMA AND A MIX ALL NGT INTO
SUNDAY FAR SERN ZONES.
REST OF EXTENDED LOOKS DRY WITH TEMPS AGAIN CLIMBING BACK ABV NORMAL.
.OMA...NONE
CHERMOK
FXUS63 KLBF 022045 ne
AREA FORECAST DISCUSSION...CORRECTED DATE
NATIONAL WEATHER SERVICE BISMARCK ND
915 PM CST FRI DEC 3 1999
FCST UPDATE HAS BEEN ISSUED. LIGHT RAIN AND SNOW WILL OCCUR ACROSS
PORTIONS OF NORTHWEST MINNESOTA...ENDING AROUND MIDNIGHT. A LATE
AFTERNOON CU FIELD ACROSS NORTHERN PORTIONS OF THE RED RIVER VALLEY
INDICATED A DESTABILIZED AREA ASSOCIATED WITH A DISTURBANCE MOVING
THROUGH THE NRN BRANCH OF THE UPR FLOW. 00Z RUC MODEL RUN PICKED THIS
FEATURE UP WELL BUT DIDNT GENERATE PCPN. 88D IMAGERY AND SFC REPORTS
INDICATE AREAS OF LESS THAN ONE TENTH INCH PCPN...BUT SUFFICIENT TO
GLAZE COOLING SURFACES. CURRENT TEMPS DONT WARRANT A FREEZING DRIZZLE
ADVISORY...BUT WILL MONITOR CLOSELY. EXPECT COOLING TEMPS WILL CONVERT
TO SNOW AS MID LEVELS SHOULD BE COOLING AS WELL. SMALL COMMA HEAD IS
EVEIDENT ON IR IMAGERY AND INDICATES THAT THIS SYSTEM MAY PERSIST
ACROSS NRN MN.
WITH VERY LIGHT SFC WINDS...EXPECT AREAS OF FOG TO DEVELOP BEHIND THE
DEPARTING DISTURBANCE...GENERALLY AFT MIDNIGHT IN NW MN. OTHER PORTIONS
OF THE CWFA WILL SEE PATCHY FOG FORMING AROUND MIDNIGHT.
A STORM SYSTEM CONTINUES TO DEVELOP IN THE PANHANDLE REGION OF TEXAS
AND OKLAHOMA. THIS STORM WILL MOVE ACROSS THE CENTRAL PLAINS FRIDAY
AND INTO THE WESTERN GREAT LAKES ON SATURDAY. THE NORTHERN PLAINS IS
STILL EXPECTED TO REMAIN CLEAR OF ANY SIGNIFICANT PRECIPITATION FROM
THIS SYSTEM. WE CAN EXPECT A FEW CLOUDS TO TRANSIT THE AREA FRIDAY
AND SATURDAY. WE CAN ALSO EXPECT THE CENTRAL PLAINS STORM TO DRAG
COOLER CANADIAN AIR SOUTHWARD...INTO THE REGION...AND INCREASE OUR
NORTHERLY WINDS BY SATURDAY.
DRY CONDITIONS ARE EXPECTED TO CONTINUE WELL INTO THE COMING WEEK.
THE WEATHER WILL TURN SLIGHTLY COOLER OVER THE WEEKEND AND CONTINUE
SLIGHTLY COOLER THROUGH THE EARLY PART OF NEXT WEEK...YET READINGS
WILL STILL BE ABOVE AVERAGE. AT THE PRESENT TIME NO MAJOR STORMS ARE
ON THE HORIZON FOR THE NORTHERN PLAINS.
.FGF...NONE.
GUST
FXUS63 KFGF 030204 nd
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE/SPARTANBURG SC
945 AM EST THU DEC 2 1999
SATELLITE IMAGERY SHOWS CIRRUS EVAPORATING AS IT TOPS THE MID LEVEL
RIDGE AXIS...WHICH THE 12Z UPPER AIR ANALYSIS SHOWS TO THE WEST OF THE
FORECAST AREA. BOTH THE 06Z ETA AND THE 12Z RUC KEEP THE RIDGE AXIS ON
THE WESTERN SIDE OF THE MOUNTAINS THRU THE END OF THE DAY. WITH THAT IN
MIND...DO NOT EXPECT HARDLY ANY CIRRUS UNTIL PERHAPS LATE IN THE
AFTERNOON...THUS SUNNY MIGHT BE MORE APPROPRIATE THAN MOSTLY SUNNY.
ZONE TEMPS LOOK GOOD FOR THE MOST PART...DO NOT ANTICIPATE ANY
CHANGES.
.GSP...NONE.
MOORE
sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
925 PM EST THU DEC 2 1999
THIS EVENING/S WATER VAPOR AND IR IMAGERY INDICATE S/W AMPLIFICATION
OVER CENTRAL OKLAHOMA...ENHANCING CONVECTION THERE AND...TO A LESSER
DEGREE...INTO ARKANSAS AND LOUISANNA. HIGH PRESSURE DOWNSTREAM...
WITH THE CENTER OF SURFACE CIRCULATION NEAR SAVANNAH GA...IS
REMAINING STATIONARY THIS EVENING. VERY DRY SURFACE AND MID-LEVEL
AIR IN THE FORECAST AREA IS MODIFYING (MOISTENING) SLOWLY. SO...FOR
TONIGHT...PARTLY CLOUDY CONDITIONS STILL LOOK GOOD. HOWEVER...
TEMPERATURES LOOK A LITTLE TOO COOL.
CONSIDERING THAT THE RUC MODEL HANDLES THE PRESSURE FALLS WITH THE
UPSTREAM SYSTEM BETTER...THE SOLUTION FOR MORE HIGH-LEVEL CLOUDS
AFTER MIDNIGHT IN THE RUC JUSTIFY THE TEMPERATURE UPDATE TONIGHT.
THE LATEST SHORT-TERM MODELS TEND TO MAINTAIN SURFACE HIGH PRESSURE
IN THE SOUTHEAST ATLANTIC COAST FOR FRIDAY WHILE...HIGHER UP...THE
RIDGE AXIS SHIFTS EAST. EXPECT THE UPSTREAM SYSTEM NOT TO BRING ANY
PRECIPITATION IN ON FRIDAY AS IT TRACKS NORTHEAST FROM THE SOUTHERN
PLAINS INTO THE MID MISSISSIPPI VALLEY BY 03/18Z...THEREAFTER
WEAKENING.
EXPECT SOME MID AND HIGH LEVEL CLOUDS FOR FRIDAY (AGAIN...PARTLY
CLOUDY SKIES LOOK TO PREVAIL). THE PRESSURE GRADIENT LOOKS STRONGER
IN THE 02/18Z MESO-ETA RELATIVE TO THE 02/12Z MODELS FOR FRIDAY...SO
WILL INCREASE WITH WINDS IN THE TENNESSEE VALLEY A LITTLE FOR THE
AFTERNOON.
THE NC CODING (NC...) AT THE BOTTOM OF THE AFD REFERS ONLY TO
CHEROKEE AND CLAY COUNTIES IN NORTH CAROLINA. THE VA CODING (VA...)
REFERS ONLY TO LEE, RUSSELL, SCOTT, WASHINGTON, AND WISE COUNTIES
IN VIRGINIA. THE TN CODING (TN...) REFERS ONLY TO EAST TENNESSEE.
OTHERS PORTIONS OF THESE STATES MAY HAVE WATCHES/WARNINGS IN EFFECT
THAT WILL NOT BE REFLECTED IN THIS AFD.
.MRX...
NC...NONE.
TN...NONE.
VA...NONE.
FXUS64 KMRX 022040 tn
SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
920 PM CST THU DEC 2 1999
00Z RUC MODEL AND SATELLITE TRENDS INDICATE SUBSIDENCE AND DRIER AIR
WEST OF THE SOUTHERN PLAINS STORM SYSTEM IS PUSHING EAST ACROSS SOUTH
CENTRAL TEXAS. THUS WILL REMOVE POPS FOR ALL AREAS. LOW LEVEL WINDS
HAVE DIMINISHED OVER WEST CENTRAL TEXAS AND THIS WILL RESULT IN A
WEAKENED DRYLINE. THE DRYLINE WILL RETREAT NORTHWEST FRIDAY AS
GULF MOISTURE BECOMES DRAWN INTO THE NEXT APPROACHING STORM SYSTEM
WHICH IS CURRENTLY OVER THE ROCKIES. WILL REMOVE MENTION OF SHIFTING
WINDS FOR ALL AREAS AS LIGHT SOUTH TO SOUTHEAST FLOW SHOULD HOLD UP
ALL NIGHT. WITH ANKLE DEEP MOISTURE STILL HOLDING TIGHT OVER THE RIO
GRANDE PLAINS, WILL MENTION PATCHY MORNING CLOUDS OVER ALL AREAS
EXCEPT THE DRT AREA. REMAINDER OF FORECAST IS ON TRACK.
.EWX...NONE.
18/19
FXUS64 KLUB 030314 tx
INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
850 PM PST THU DEC 02 1999
PRIMARY FORECAST PROBLEM THIS EVENING CONCERNS FROST POTENTIAL IN
CENTRAL/SOUTHERN SJ VALLEY. SAT PICS SHOW MID-HIGH LEVEL MOISTURE
LINGERING IN THE WAKE OF DISSIPATED COLD FRONT AND ASSOCIATED
SHORTWAVE DIVING SE ACROSS NV. SFO-LAS GRAD REMAINS AT A HEALTHY 14
MB THIS EVE...KHNX VWP SHOWS 15-20 KT WINDS JUST ABOVE SURFACE...AND
MESO-ETA/RUC SHOW CAA CONTG OVERNIGHT WITH 20KT FLOW THROUGH LOW
LEVELS. NEVERTHELESS...DECOUPLING OF LOWER LEVELS HAS ALLOWED WINDS
AT MOST VALLEY LOCATIONS TO DIMINISH TO LESS THAN 10 MPH AT 04Z...
TRANSPARENCY OF HIGH CLOUDS WILL REMAIN CONDUCIVE FOR RADIATIVE
LOSSES OVERNIGHT...AND CAA SHOULD ALLOW FOR SLIGHTLY LOWER MINS BY
SUNRISE. ADDITIONALLY...SURFACE DEW POINTS CURRENTLY IN UPPER 30S TO
LOWER 40S SHOULD DECREASE A FEW DEGREES BY SUNRISE. ALTHOUGH
MAJORITY OF VALLEY TEMPS SHOULD REMAIN IN MID 30S OVERNIGHT...
POTENTIAL REMAINS FOR A FEW COLDER WIND-SHELTERED LOCATIONS TO DROP
SLIGHTLY BELOW FREEZING AROUND DAYBREAK AND CURRENT FROST ADVISORY
FOR LATE TONIGHT/EARLY FRI MORNING WILL BE CONTINUED.
OTHERWISE...SURFACE GRAD WAS SUPPORTING BREEZY CONDITIONS OVER KERN
MOUNTAINS AND DESERTS THIS EVE AND WINDS MAY CONT OVERNIGHT AS PROGS
SHOW CAA AND SUBSIDENCE CONTG THROUGH LOW-MID LEVELS. ALIGNMENT OF
SURFACE GRADS WITH FLOW ALOFT SHOULD ALSO SUPPORT SOME CONTD UPSLOPE
CLOUDS OVER SIERRA FOOTHILLS/KERN MOUNTAINS.
NO UPDATES PLANNED AT THIS TIME.
.HNX...FROST ADVISORY FOR THE CENTRAL AND SOUTHERN SAN JOAQUIN
VALLEY LATE TONIGHT AND EARLY FRIDAY MORNING.
JSN
FXUS66 KMTR 030628 COR ca
WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
300 AM MST FRI DEC 3 1999
UPPER LOW CENTERED OVER SOUTHERN UTAH IN THE PROCESS OF CLOSING OFF.
SNOW HAS DEVELOPED IN THE REGION OF UPPER DIVERGENCE.. AT 09Z THIS
COVERED EAST CENTRAL UTAH AND WEST CENTRAL COLORADO. SURFACE COLD
FRONT CUTTING ACROSS SOUTHEAST UTAH WITH WIND SHIFT AT KCNY AT 0835Z.
FRONT WILL CONTINUE TO SAG SOUTHWARD WITH AREAS OF LIGHT SNOW
DEVELOPING BEHIND IT. LOCATIONS THAT NORMALLY DO NOT SEE A LOT OF
SNOW MAY SEE A LITTLE OF IT THIS MORNING. MODELS DOING A BETTER
HANDLING UPPER LOW THAT MOVES INTO NORTHEAST NEW MEXICO BY EVENING.
DESPITE SOME DIFFERENCES.. FORECASTS WOULD NOT DIFFER MUCH REGARDLESS
WHICH MODEL IS CHOSEN. THE SHORT TERM RUC MODEL MOST APPROPRIATE
HERE SINCE MOST OF THE WEATHER WITHIN COUNTY WARNING AREA OCCURS IN
THE FIRST 12 HOURS. DESPITE SUFFICIENT MOISTURE AND HIGH RELATIVE
HUMIDITIES.. WIND FLOW VEERS TO A NORTHERLY COMPONENT AND THAT'S NOT
FAVORABLE FOR A LOT OF MOUNTAIN SNOW EXCEPT ISOLATED AREAS. PARTS
OF THE GRAND MESA.. THE FLAT TOPS.. AND THE NORTH FACING SLOPES OF
THE SAN JUANS MAY BE THE WINNERS WITH THIS PARTICULAR SYSTEM.. TOTAL
SNOWFALL AMOUNTS MAY REACH THE 6 TO 10 INCH RANGE. LESSER AMOUNTS
WILL OCCUR ELSEWHERE WITH SOME AREAS STRUGGLING TO REACH SNOW
ADVISORY AMOUNTS.. LIKE ZONE 12 (WEST ELK AND SAWATCH MOUNTAINS).
THE BEST LIFT AND INSTABILITY WILL BE SOUTHEAST OF THE FORECAST AREA
BY TONIGHT.. THEREFORE WILL NOT EXTEND THE CURRENT SNOW ADVISORY.
WITH SUBSIDENCE AND DOWNSLOPE NORTH NORTHEAST FLOW FOR MANY AREAS..
WILL ADVERTISE PARTIAL CLEARING TONIGHT. GIVEN THE AMOUNT OF LOW
LEVEL MOISTURE.. WILL INTRODUCE PATCHY FOG DEVELOPING IN THE VALLEY
LOCATIONS. EXPECT CLEARING IN EARNEST FROM THE WEST WITH PREVAILING
NORTHERLY FLOW.. BUT EXPECT SOME CLOUDS AND LINGERING SNOW FLURRIES
NEAR THE DIVIDE ON SATURDAY. FRISBIE
WESTERN COLORADO AND EASTERN UTAH EMERGENCY MANAGERS SHOULD MAINTAIN
A HIGH LEVEL OF WEATHER AWARENESS TODAY FOR MOUNTAIN SNOWFALL.
.GJT...SNOW ADVISORY TODAY...COZ004-009-010-012-018-019.
FXUS65 KBOU 030430 co
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
345 AM CST FRI DEC 3 1999
SEVERAL FORECAST CHALLENGES TO DEAL WITH IN FIRST PERIOD. HAVE
FOCUSED ON ETA/AVN SOLUTION IN LONG TERM WITH WEAKER LOW PRESSURE
SYSTEM VCNTY OF AR BY 48 HOURS AS NGM APPEARS A BIT OVERDONE
CONSIDERING AMOUNT OF UPSTREAM RIDGING DEVELOPING AHEAD OF NEXT NRN
PACIFIC SYSTEM. HENCE TRENDING TWD DRIER ALL AROUND FCST AS LATEST
MRF GUIDANCE HAS ALSO SWITCHED BACK TO MORE SOUTHERN SYSTEM WITH
HIGH PRESSURE IN CONTROL FOR EXTENDED PERIOD...IN GOOD AGREEMENT
WITH LATEST UK MODEL.
FIRST SHORT TERM CONCERN FOCUSES ON DENSE FOG POTENTIAL IN WRN AREAS
OF ZONE FORECAST AREA. CLEARING AREA WELL HANDLED BY LATEST RUC
GUIDANCE AS WEAK SFC LOW IN SERN MN CONTS TO WKN. DVLPG LGT NLY
FLOW IN ITS WAKE IS BEGINNING TO SPREAD SC SHIELD OVR ERN
DAKOTAS/NRN MN SWD INTO THIS AREA. ALSO LATEST 11-3.9 MICRON
IMAGERY ALSO SHOWING MORE SC DVLPMT VCNTY OF RWF IN ADDITION TO CI
SHIELD SPREADING RAPIDLY NWD THRU IA. HENCE WL ONLY MENTION MORNING
FOG...POTENTIALLY DENSE IN CURRENT AREA OF CLRING AS WDSPD DENSE FOG
NOT LIKELY.
POTENT S/W OVR SERN KS EJECTING RAPIDLY NEWD TWD LK MI TDY WITH DEEP
MOISTURE ALG AND AHEAD OF ITS PROGRESS...CUTTING OFF DEEP MOISTURE
ADVECTING INTO SRN MN. WEAKENING MID LEVEL CIRCULATION LKLY TO
PRODUCE SOME DEFORMATION -RA AND 295-300K SFCS SHOWING ENOUGH LIFT
FOR SATURATION PUSHING THRU IA INTO SRN WI TDY...WITH BEST LIFT
CLIPPING SERN MN. PATCHY -RA ALREADY BEGINNING TO DVLP IN NRN IA.
WL CONT SML POPS IN AREAS BDRG ARX/DMX AREAS WITH MENTION OF -DZ OR
SPRINKLES FTHR NORTH. LOW LEVEL RH REMAINS QUITE HIGH THROUGH LATER
PERIODS AS MID LEVEL TROUGH MOVES THROUGH MN AS IT PHASES WITH SRN
SYSTEM. COLD AIR ADVECTION MAY BE A BIT OVERDONE. WL REEXAMINE IN
LTR SHIFTS. WL CONT MENTION OF -SHRA/-SHSN WITH PASSAGE OF SAID
TROUGH ON SAT. GUIDANCE TEMPS NOT BAD BUT MAY NEED TO ADJUST
DOWNWARD SLIGHTLY TO ACCOUNT FOR SC IN WEST.
COORD WITH ARX..DMX..FSD..FGF.
.MSP...NONE.
KAVINSKY
FXUS63 KMPX 030243 mn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
215 AM EST FRI DEC 03 1999
DISC: LATEST RUC2 COMPOSITE FROM SPC SHWS 150+ JET AT 300H DIGGING
DOWN W COAST AND EJECTING S/W OVER OK/MO NE AND PLENTY OF MID/HI LVL
MOIST INTO CFA TDY. STRONG UPER RIDGE IN PLACE WILL BREAK DOWN TONIGHT
AS S/W APRROACHES AND SKIRTS BY NRN AREAS WITH CHANCE OF SHWRS.
CLDS WON'T HAVE MUCH OF AN IMPACT ON TEMPS ACROSS THE REGION. UPSTEAM
HIGH WERE IN THE MID 50S TO 60S THU AND WITH WINDS AT 80H W-SW WAA
WILL BRING IN SLIGHTLY ABV NORMAL TEMPS. DEW POINTS WILL ALSO BE
RISING TO MAKE IT "FEEL" MORE COMFORT TDY AND SAT.
VERY PROGRESSIVE PATTERN THRU EARLY NEXT WEEK AS RIDGE MOVES OFFSHORE
SUN AND BACK DOOR FRONT DROPS DOWN EARLY MONDAY. 72H AVN SIM TO LAST
MRF RUN WITH DEEP 50H LO OVER MO SUN EVENING REMAINING N OF CFA AS
SFC FRONT BRINGS CHC SHWRS ON MON.
ALL IN ALL...NOT A BAD OUTLOOK. PCPN IS STILL LIQUID AS COLDEST AIR
BASICALLY HUNG UP AT 60N THRU BETTER PART OF NEXT WEEK. RECORDS HAVE
SHOWN(GIGI RESEARCH) THAT DEC AVERAGES ABT 1.4 DEGREES ABV NRML
FOLLOWING 12 WARMEST NOVEMBERS ON RECORD. NOV 1999 RANKED 7TH. ONLY
2 OF THE TWELVE HAPPENED TO BE LA NINA WINTER...WHICH IS NOT THAT
DIFFERENT FROM EL NINO TEMPS DURING THE WINTER.
SW WINDS AT 44009 AND AIR TEMPS STILL 50 DEG. WAVES HAVE SUBSIDED
AND NO FLAGS TODAY.
SEE YA...
.PHI...NONE.
EBERWINE
FXUS61 KPBZ 030724 pa
AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST
SOUTH DAKOTA AND WEST CENTRAL MINNESOTA
NATIONAL WEATHER SERVICE ABERDEEN SD
340 AM CST FRI DEC 3 1999
FORECAST CHALLENGES THIS PERIOD INCLUDE EXTENT OF FOG THIS MORNING
AND CHANCES FOR LIGHT SNOW FRI NIGHT AND SAT. SURFACE PRESSURE
GRADIENT VERY LIGHT AT THIS TIME...WITH MSAS ANAL SHOWING LIGHT N
WINDS ONLY OVER FAR EAST COUNTIES...A WEAK LOW OVER W. SD AND A VERY
WEAK HIGH JUST ACROSS ND BORDER TO OUR N...AND VERY PERSISTENT L/L
RH. ADJUSTING FOR CURRENT SFC TEMP AT ABR...00Z ABR SOUNDING SHOWS
IVERSION TRAPPING NEAR SURFACE MOISTURE. RUC AND ETA TIME-HT
SECTIONS THROUGH THE MORNING KEEP THE SHALLOW MOISTURE IN...THUS
WILL KEEP DENSE FOG ADVISORY OUT FOR MOST OF CWA THROUGH MID
MORNING. AS FOG BEGINS TO FINALLY BREAK UP...DEEPER MOISTURE WILL
COME INTO LOW-MID LEVELS UP TO AS HIGH AS 700 MB...SO LITTLE IF ANY
SUN EXPECTED TODAY. MODELS SIMILAR IN GENERAL FEATURES AND
TRENDS...AND FOLLOWED A GENERAL AVN/ETA SOLUTION FOR THE DETAILS.
BEST MOISTURE AND DYNAMICS STAY WITH UPPER LOW TO THE SOUTH AND
SOUTHEAST. FOR US...WEAK NORTHERN STREAM U/L TROUGH PUSHES THROUGH
OVERNIGHT FRI-SAT. LIFT UNIMPRESSIVE FOR ABR CWA...BUT SUFFICIENT
MOISTURE FOR KEEPING IN 20 POPS FOR SOUTHERN AND FAR EASTERN
COUNTIES. TEMPS INDICATED SLIGHT POSSIBILITY PRECIP IN EASTERN
COUNTIES MIGHT BEGIN AS -RA...BUT BEST MOISTURE COMES IN FOLLOWING
WBZ TEMPS DROPPING TO OR BELOW 0C. FOR AREAS NORTH AND
WEST...PICTURE IS SIMILAR...BUT EVEN LESS MOISTURE AND LIFT...SO
INDICATED POSSIBILITY OF FLURRIES IF ANYTHING. FAN AND FWC TEMPS REASONABLY
CLOSE AND USED A BLENDING OF THE TWO FOR THE MOST PART.
.ABR...DENSE FOG ADVISORY...FOR MOST OF CWA...EXCEPT BUFFALO...BIG
STONE...AND TRAVERSE COUNTIES...TILL 10 AM CST...9 AM MST.
LORENS
FXUS63 KFSD 030438 sd
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
ISSUED BY NATIONAL WWEATHER SERVICE GAYLORD MI
1110 AM EST FRI DEC 03 1999
LOW IN SOUTHEAST NEB WITH A FRONT THAT RUNS ACROSS WISC AND NORTHERN
LAKE MICHIGAN. THE FRONT'S NORTHERN PROGRESSION IS BEING IMPEDED BY
THE H5 VORT MAX NORTH OF LAKE SUPERIOR. THIS IS KEEPING MOST OF THE
MOISTURE IN NORTHERN LOWER MICHIGAN...WHILE DRIER AIR TRIES TO BREAK
UP THE CLOUDS JUST TO THE WEST IN THE ARROWHEAD REGION OF MINNESOTA
AND OVER LAKE SUPERIOR.
RUC AND MESOETA LOOK TO BE HANDLING THE SITUATION OKAY. THERE ARE A
FEW MORE HOLES IN THE CLOUDS OUT UPSTREAM THAN THE MODELS WOULD
INDICATE. HOWEVER...1000-850 MOISTURE MOVES BACK IN AND STAYS
TRAPPED UNDER THE INVERSION WHILE 850-500 LAYER CONTINUES TO DRY.
THIS MEANS THAT FOG PROBABLY DOESN'T DEVELOP UNTIL THE EVENING SO
WILL PULL THE FOG OUT OF THE FORECAST FOR THE AFTERNOON FOR MOST OF
THE WESTERN ZONES AND GO WITH SPRINKLES IN THE SOUTHERN ZONES AS
MOST OF THE PRECIPITATION IS FOCUSED IN LOWER MICHIGAN AND SOUTHERN
WISCONSIN. HOWEVER...THE RAIN WILL WORK ITS WAY BACK IN THIS
EVENING. TEMPERATURES LOOK PRETTY GOOD SO FAR.
.MQT...NONE.
LUTZ
FXUS63 KDTX 031550 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE/SPARTANBURG SC
940 AM EST FRI DEC 3 1999
SATELLITE IMAGERY SHOWS EXTENSIVE MID TO HIGH CLOUDINESS MOVING UP THE
BACK SIDE OF THE MID/UPPER RIDGE...WHOSE AXIS WAS LOCATED OVER THE
CAROLINAS ON THE 12Z UPPER AIR ANALYSIS. THE EDGE OF THE THICKER CLOUDS
CORRESPONDED ROUGHLY TO THE EDGE OF THE MOUNTAINS. LOOKING AT RECENT
SATELLITE TRENDS...IT WOULD APPEAR THAT THE 06Z ETA AND 12Z RUC HAVE
THE RIGHT IDEA WITH KEEPING THE THICKER CLOUDS FROM THE MOUNTAINS
WESTWARD THROUGHOUT THE DAY. FURTHERMORE...THESE MODELS LIFT THE
RELATIVELY HIGHER UPPER LEVEL RH CURRENTLY OVER THE MOUNTAINS OFF TO
THE NE THIS AFTERNOON. WITH THAT IN MIND...THINK THE CIRRUS EAST OF THE
MOUNTAINS WILL REMAIN THIN...MEANING THAT WE WILL HAVE ESSENTIALLY A
BRIGHT DAY WITH THE SUN SHINING THRU THE HIGH CLOUDS...AND MAY TWEAK
THE WORDING A BIT. TEMP TRENDS LOOK OK FOR NOW.
.GSP...NONE.
MOORE
FXUS62 KCHS 030754 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
ISSUED BY NATIONAL WEATHER SERVICE MARQUETTE MI
1135 AM EST FRI DEC 3 1999
WV LOOP SHOWS ONE SHORTWAVE OVER EASTERN KANSAS AND ONE OVER WESTERN
LAKE SUPERIOR. 15Z SURFACE ANALYSIS SHOWS LOW PRESSURE ASSOCIATED
WITH SOUTHERN SHORTWAVE LOCATED NEAR NORTHWEST MISSOURI...WITH A
WARM FRONT ARCING NORTHEAST TO THE STRAITS AND THEN DOWN INTO
SOUTHERN ONTARIO. KAPX/KGRR/DTX 88D LOOPS SHOW SCATTERED LIGHT
SHOWERS OVER NORTHERN LOWER...WITH A MORE WIDESPREAD BAND OF PRECIP
APPROACHING FROM THE SOUTH.
NORTHERN SHORTWAVE WILL HELP TO PUSH SOUTHERN SHORTWAVE TO THE EAST.
12Z RUC/06Z MESOETA KEEP IT SOUTH OF UPPER MICHIGAN. WITH MODEL
RESOLUTION NOT ABLE TO PICK UP ON CURRENT PRECIP BAND EXTENDING FROM
THE THUMB THROUGH SOUTHERN WISCONSIN...THEY DO HINT AT MORE
WIDESPREAD PRECIP. 295K/300K ISENTROPIC LIFT...850-500MB QVECTOR
CONVERGENCE WITH THE SHORTWAVE...300MB DIVERGENCE IN LEFT EXIT
REGION OF JET STREAK ALL POINT TO PRECIP TRACKING NORTHEAST ACROSS
NORTHERN LOWER MICHIGAN. MAIN FORCING STAYS SOUTH OF UPPER
MICHIGAN...BUT STILL A CHANCE WITH AMOUNT OF LOW-LEVEL MOISTURE NEAR
THE WARM FRONT.
LINEAR EXTRAPOLATION OF MAIN PRECIP BAND INDICATES ARRIVAL IN
HTL-OSC BY 18Z AND IN APN-TVC BY 20Z. PRECIP WILL CONTINUE NORTHEAST
WITH MOVEMENT OF SOUTHERN SHORTWAVE...WITH HIGHEST POPS OVER
SOUTHERN CWA AND LOWEST OVER NORTHERN/EASTERN UPPER.
WITH CLOUDS...RAIN...AND FOG...EXPECT TEMPERATURES WILL ONLY CLIMB
BY A FEW DEGREES IN THE SOUTHERLY FLOW. GIVEN CURRENT METARS...WILL
TWEAK TEMPERATURES UP A LITTLE FOR MOST AREAS.
.APX...NONE.
JHB
FXUS63 KMQT 031607 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
1130 AM CST FRI DEC 3 1999
COMPLEX PATTERN IN THE SHORT TERM AS WESTERN SYSTEM BEGINS TO EXERT
GREATER INFLUENCE ON AREA. ZONES WILL BE ADJUSTED FOR THIS AFTERNOON
BASED ON EVOLUTION OF SURFACE FEATURES AS DEPICTED ON LATEST RUC.
WELL-DEFINED SURFACE BOUNDARY ON MESONET DATA NOW LIES FROM E
CENTRAL TO S CENTRAL OK AND IS PROGGED TO MOVE ONLY SLOWLY NW, IF AT
ALL, THIS AFTERNOON. WINDS NW OF BOUNDARY EXPECTED TO VARY FROM E-NE
IN NW OK TO E-SE ELSEWHERE ACROSS CENTRAL AND SW OK. MAY HAVE TO
ADJUST SOME MAX TEMPS AS THIS BOUNDARY SHOULD STRENGTHEN, LEADING TO
A SUBSTANTIAL THERMAL GRADIENT.
CONCERN FOR SEVERE T-STORMS BEGINS THIS EVENING AS 850 FLOW BACKS
AND LLJ STRENGTHENS NEAR OR JUST E OF I-35 CORRIDOR, RESULTING IN
STRONG LOW LEVEL SPEED CONVERGENCE AND ISENTROPIC LIFT ALONG
STRENGTHENING BAROCLINIC ZONE. DRAWBACK MAY BE DEPTH OF LOW-LEVEL
MOISTURE NOW SITTING OVER E TX AND SE OK, AS LITTLE OF IT APPEARS AT
850MB THIS MORNING. HOWEVER, DYNAMIC FORCING SUGGESTS POTENTIAL FOR
ANOTHER ACTIVE NIGHT, PERHAPS BEGINNING EARLY TO MID EVENING,
ESPECIALLY IF MOISTURE RETURN IS SUFFICIENT.
THIS AFTERNOON WE ALSO WILL BE LOOKING VERY CLOSELY AT THE SNOW
POTENTIAL OVER PARTS OF N AND W OK LATE SAT AND SAT NIGHT. EARLY
INDICATIONS FROM 12Z MODEL DATA ARE THAT THERE IS AN INCREASING
CHANCE OF SIGNIFICANT ACCUMULATIONS, AT LEAST IN THE NW. MORE IN
THIS LATER THIS AFTERNOON.
24
.OUN...
OK...NONE.
TX...NONE.
FXUS64 KTSA 031635 ok
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
315 PM EST FRI DEC 3 1999
ETA APPEARS TO BE THE BEST MODEL FOR 48 HR FCST AS AVN TOO FAST WITH
SWRN U.S. UPR LO. NGM BETTER BUT POSSIBLY TOO DEEP AND SLOW WITH
SYSTEM. 1ST VORT BUILDING NE ACROSS MID/ERN TN AND HAVE NOTED LIGHT
PRECIP AMOUNTS OVR WRN/MID TN WITH THIS SYSTEM. MODEL SOLUTIONS
SHOW WEAKENING TREND WITH MOVEMENT INTO RIDGE POSITION WHICH IS
CURRENTLY HAPPENING. STILL...BELIEVE THERE COULD BE A FEW DROPS
HERE AND THERE AND USED SPRINKLES FOR THE "LEFTOVER" WX THRU FCST
VALID TIME AND A LITTLE BEYOND. YET ANOTHER...STRONGER FEATURE
EVIDENT ON WATER VAPOR IMAGERY OVR E TX/SW LA WHICH IS DISPLAYED ON
MODELS AS STREAKING NNE THRU MS VLY TWD LWR OH VLY PRESENTS THE
BIGGEST PROBLEM WITH FCST. DECIDED TO KEEP POPS OUT FOR TONITE IN
ASSOCIATION WITH THIS S/WV AS LATEST RUC IN ADDITION TO MAIN MODEL
RUNS PUSH LIFT/MOISTURE THRU WRN/MID TN WITHOUT MUCH IMPACT OTHER
THAN CLOUDS FOR E TN.
CLEARING TREND OCCURS BEHIND THIS SYSTEM BY MID DAY SAT BUT WILL
NOT GET FANCY WITH SKY CONDITION WORDING AND JUST USE PC. WEAK SLY
FLO CONTINUES THRU SAT NITE WITH MOSTLY CLEAR SKIES AWAITING
ARRIVAL OF UPR LO AND ATTENDANT FNTL SYSTEM WHICH WILL BE MOVG THRU
MS VLY BY 12Z SUN. USED AN INCREASING CLOUD TREND ON SUN WITH SMALL
CHC POPS FOR AFTERNOON/LATE AFTERNOON AS BELIEVE BEST CHC OF RAIN
WILL BE SUN NITE/MON MORNING. ALTHOUGH...AM UNCERTAIN ABOUT HOW
FAST TROF DEPARTS ON MONDAY AFTER A LOOK AT MRF SO DIDN'T GET FANCY
WITH IMPROVEMENT IN WX ON 1ST DAY OF EXTENDED.
GENERALLY TOOK MIDDLE OF THE ROAD APPROACH OR CONCENSUS ON TEMPS
THRU PD.
CHA 046/066 044/065 050 20100
TYS 042/062 042/063 048 20100
TRI 039/060 040/063 045 20-00
OQT 042/062 042/063 048 20100=
.MRX...
NC...NONE.
TN...NONE.
VA...NONE.
FXUS64 KMEG 032015 tn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
111 PM CST FRI DEC 03 1999
17Z SURFACE ANALYSIS STILL SHOWS WEAK RIDGING ACROSS THE SOUTHEAST
WITH COLD FRONT LOCATED OVER THE SOUTHERN PLAINS AND LOW JUST N OF
TOP. DESPITE THE STABILITY DEPICTED BY THE 12Z BNA SOUNDING...
SHOWERS CONTINUE MOVING ACROSS THE NASHVILLE CWA. 19Z DEWPOINTS
ACROSS MIDDLE TN WERE STILL LOW...30 AT CSV...48 AT BNA...ALTHOUGH
PRECIPITATION HAS HELPED TO INCREASE DEWPOINTS.
12Z BNA SOUNDING SHOWS SFC TO 600 MB LAYER AS BEING QUITE
DRY...ALTHOUGH CURRENT 6000 FT CEILING SHOWS THE MOIST LAYER HAS
EXTENDED DOWNWARD. JAN-BNA CROSS SECTION USING LATEST RUC MODEL DOES
SHOW GOOD ISENTROPIC LIFT WITHIN THIS MOIST LAYER...AND BELIEVE THIS
TO BE THE CULPRIT IN SHOWER FORMATION THIS MORNING.
ETA/NGM/AVN DO SHOW SOME DIFFERENCES AMONG THE 12Z CYCLES. AVN
APPEARS MOST AGGRESSIVE WITH PRECIPITATION ASSOCIATED WITH THIS
SYSTEM. NGM IS A LITTLE FASTER THAN ETA...BRINGING IN BEST LIFT/
MOISTURE BEFORE 12Z SUN...WHERE ETA HOLDS OFF SEVERAL HOURS. ETA
SEEMS TO BE VERIFYING BEST AT THIS TIME...ESPECIALLY WITH
DEVELOPMENT ALONG THE GULF COAST. WITH WEAK 300 MB JET DYNAMICS...
SLOWER ETA SOLUTION MAY BE BEST. SO WILL GO WITH ETA AS MODEL OF
CHOICE THIS FORECAST.
WITH FRONT HANGING TO THE WEST...STRONG SOUTHERLY/SOUTHWESTERLY FLOW
SURFACE AND ALOFT THROUGH 48 HRS...AND GOOD MOISTURE FEED...BELIEVE
AT LEAST SCATTERED POPS ARE WARRANTED THROUGH THE FORECAST PERIOD.
BEST CHANCE OF RAIN APPEARS TO BE SUNDAY...AS FRONT FINALLY STARTS
TO MOVE EASTWARD AND DEEP 500 MB LOW FORMS OVER NE OK/SE KS. WILL
MENTION THUNDERSTORMS IN THE PERIOD 4 FORECAST ALONG WITH HIGHER
POPS.
FWC/FAN GUIDANCE TEMPERATURES ARE REASONABLY CLOSE THROUGH PERIOD
3...AND WILL USE A BLEND OF THESE NUMBERS IN THE UPCOMING ZFP.
MODELS DISSAGREE ON POPS W/ FAN VALUES MUCH HIGHER THAN FWC. WILL
STAY BETWEEN THESE NUMBERS AND GO A LITTLE HIGHER THAN FWC PERIODS
2-4.
EXTENDED MODELS FINALLY SHOW FRONT MOVING THROUGH MIDDLE TN MONDAY
EVENING...ALTHOUGH COOLING BEHIND THE FRONT WILL BE MINIMAL.
BNA 54/67/51/61 5325
CSV 44/62/46/56 4214
.BNA...NONE.
08
FXUS64 KOHX 031604 tn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
310 PM CST FRI DEC 3 1999
ANOTHER VIGOROUS UPPER LEVEL STORM WILL MOVE ACROSS THE AREA TONIGHT
AND SATURDAY. IT NOW APPEARS THAT THE ETA'S SOLUTION IS THE BEST
OF THE THREE LARGE SCALE MODELS...AND WE WILL FOLLOW IT FAIRLY
CLOSELY. A SURFACE LOW WILL REFORM THIS EVENING...SOMEWHERE FROM
NEAR CHILDRESS SOUTHWARD. THE RED RIVER WOULD BE A LOGICAL PLACE FOR
LOW FORMATION....GIVEN THE STATIONARY FRONT THAT EXTENDS FROM NORTH
OF AMA TO NORTH OF SPS AND NEAR TULSA THIS AFTERNOON. UNSTABLE...
MOIST AIR WILL MOVE QUICKLY NORTHWESTWARD TONIGHT...ALBEIT WITH A BIT
OF A CAP...ACCORDING TO THE RUC2 MESOSCALE MODEL. THE BEST AREA FOR
CONVECTIVE INITIATION WILL BE NEAR THE FRONTAL BOUNDARY IN
OKLAHOMA...WITH THUNDERSTORMS THEN BUILDING SOUTHWARD ALONG A DRY
PUNCH THAT MOVES NORTHEAST WITH THE SURFACE LOW. STORM WILL FIRE IN
THE WESTERN ZONES SOMETIME AFTER MIDNIGHT..AND MOVE RAPIDLY
NORTHEAST. WESTERN AND CENTRAL AREAS WILL CLEAR QUICKLY SATURDAY AS
A DRY SLOT WRAPS INTO NORTH TEXAS.
THE GREATEST CONCERN THAT I HAVE IS THE THREAT OF DAMAGING WINDS
AND TORNADOES. ETA FORECASTED WINDS ALOFT INCLUDE AN ACCELERATION OF
THE MID-LEVEL FLOW TO ABOUT 75 KT AT 500 MB BY SUNRISE...RIGHT ACROSS
OUR NORTHWESTERN AND NORTHERN ZONES. THIS WOULD PLACE 0-6 KM SHEARS
INTO THE 55-60 KT REALM...WHICH IS VERY STRONG STUFF. A RELEVANT
QUESTION IS WHETHER OR NOT LIFTING MECHANISMS CAN SCOOP UP SURFACE
PARCELS TO BE INGESTED INTO THE UPDRAFTS. IF THEY CAN, THEN THESE
INTENSE SHEARS WOULD BE REALIZED...RESULTING IN A THREAT OF FAST-
MOVING TORNADIC SUPERCELLS/BOW ECHOES. BECAUSE OF THE POTENTIAL...
SPOTTERS MAY BE CALLED UPON LATE TONIGHT.
NORTH TEXAS LIKELY WILL BE "DRY SLOTTED" SATURDAY...RESULTING IN
SOME SUN AND GUSTY SOUTHWEST WINDS. COLDER AIR...LOW CLOUDS...AND
GUSTY NORTHWEST WINDS WILL MOVE IN SATURDAY NIGHT. SKIES SHOULD
CLEAR SOMETIME SUNDAY AFTERNOON.
MOS TEMPERATURES ARE TOO COOL TONIGHT AND SATURDAY...BUT LOOK GOOD
OTHERWISE. WILL FASHION POPS CLOSE TO, OR SLIGHTLY ABOVE MOS
VALUES...BUT CUT THEM OFF IN PERIOD THREE (SATURDAY NIGHT).
.EXTENDED DISCUSSION: A SLIGHT CHANCE OF THUNDER AGAIN WEDNESDAY AS
ANOTHER SYSTEM MOVES IN FROM THE NORTHWEST.
.FTW...CAUTION ON AREA LAKES TONIGHT.
DFW 61/65/39/52 3511 ACT 64/69/41/55 2400
26
FXUS64 KBRO 032130 tx