AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
959 PM CST SAT DEC 4 1999
MAIN CONCERN WL BE OUR DEFORMATION ZN PCPN AFFECTS FA OVNGT. WATER
VAPOR IMAGERY SHOWS SPLIT LG WV TROF MOVG THRU CNTRL CONUS WITH SHRT
WV AXIS JUST ENTERING EXTRM NWRN IA...AND SRN SYS PUSHING THRU
OK/KS. 00Z RUC CONTS TREND OF PUSHING SRN CIRCULATION TO JUST S OF
STL EARLY TMRW. EXTRAPOLATION OF IR STLT TRENDS BRINGS DEFORMATION
ZN PCPN TWRD DSM ARND 08Z WITH SRN EDGE OF ENHANCEMENT AND MOST
SGFNT UVM TWRD KOTM. 00Z RUC SOUNDINGS AND PARTIAL THICKNESSES
SUGGEST CHG TO ALL SNW IN CNTRL IA BY 09Z AND THEN TWRD KOTM ARND
12Z. ROAD AND SFC TEMPS TOO WRM FOR MUCH ACCUMULATIONS IN SERN ZNS
BUT GRASSY AREAS COULD SEE AN INCH OR SO AFT MELTING BASED ON RUC
QPF. IT WOULD NOT LAST LONG HWVR. ALSO PUSHED PCPN MORE INTO SUN
BASED ON 00Z RUC AND CURRENT RADAR/STLT TRENDS.
LOWERED TEMPS A CATEGORY IN SOME NRN ZNS AND ADJUSTED WNDS TO FIT
CURRENT WX.
.DSM...NONE
SMALL
FXUS63 KDMX 042019 ia
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
318 PM CST SAT DEC 4 1999
...THREAT OF WINTER WEATHER BIGGEST CHALLENGE THIS AFTERNOON...
ALL MODELS IN AMAZING AGREEMENT. HOWEVER...RUC MAY HAVE A LITTLE
BETTER TRACK OF ONGOING SHORT TERM TRENDS. SATELLITE AND PROFILERS
BIG HELP IN FORMING FORECAST DECISION TOO. APPEARS STRONGEST WINDS
AT JET LVL HAVE ROUNDED BASE OF TROF AND ARE BEGINNING TO NUDGE ON
EAST SIDE OF SYSTEM. THUS AM CONCERNED THAT DRY SLOT WILL OVERTAKE
ERN PTN OF CWA WITH LITTLE IN THE WAY OF PCPN LATER TONIGHT.
LIKEWISE...BEST CHC FOR MEASURABLE SNOW WOULD BE OVER NWRN PTN OF
CWA. SFC LOW MAY BE TAKING A MORE NORTHERLY TRACK THAN ALL MODELS
SHOW...LIKEWISE UPPER SYSTEM. HOWEVER...TEMPERATURES ABOVE FREEZING
AND LIGHT RAIN WOULD PRECLUDE INITIAL ACCUMULATIONS ONCE SNOW
BEGINS.
SOME CSI EARLY IN FORECAST PD BUT THIS DIMINISHES AS TIME WEARS ON
AND TEMPERATURES FALL. SOME NEGATIVE EPV THROUGH THE NIGHT SO
CONVECTIVE POTENTIAL STILL THERE ESP. ERN PTN OF CWA. FLAMING
MESSAGE ON MOISTURE CHANNEL LOOPS IS THE DRY SLOT INTO MUCH OF WRN
OK ATTM. RUC ALSO HAS A FAIRLY GOOD GRIP ON THIS DRY SLOT. BOTTOM
LINE IS DEFORMATION AXIS AND FURTHER NORTH TRACK OF SYSTEM...SHOULD
PUT NWRN PTN OF CWA IN GREATEST THREAT. SPECIFIC HUMIDITIES NOT AS
IMPRESSIVE THIS RUN...ON THE ORDER OF 3 G/KG. THUS APPEARS WITH
TEMPERATURES WHERE THEY ARE...AND SOME MELTING TO OCCUR...BEST BET
IS TO REPLACE WSW WITH AN ADVISORY FOR TWO TO FOUR INCHES. OF
COURSE...THESE AMOUNTS HIGHLY DEBATABLE DUE TO MELTING. RAPID END TO
PCPN IN THE MRNG WITH CLEARING NOT FAR BEHIND. THUS WILL ONLY CARRY
HIGHLIGHTS OVRNGT.
.TOP...WINTER WEATHER ADVISORY FOR WIND AND SNOW NWRN AND PARTS OF
NERN KS. ALG AND NORTHWEST OF A LINE FROM COUNCIL GROVE TO HOLTON TO
HIAWATHA.
FXUS63 KDDC 042114 ks
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
453 AM MST SAT DEC 4 1999
ATTM THE LARGE AREA OF RASN WAS DIMINISHING AS A 5H/VORT MAX DRIFTS
NE AWAY FROM THE FA BUT A WEAK ELONGATED VORT MAX REMAINS ACRS THE
CWA THRU MORNING. GROUND TMPS ACRS MOST OF THE TRI-STATE AREA HAVE
BEEN ABOVE FREEZING AND THE SN THAT HAS BEEN FALLING WAS ACCUMULATING
MAINLY ON GRASSY SURFACES.
ON RADAR AND SATL ANOTHER AREA OF SN DEVELOPED OVR THE TEXAS
PANHANDLE AND MOVED NORTH INTO THE FA. THIS AREA OF PCPN WAS ROTATING
AROUND AN INTENSE MID LVL LOW THAT AND WAS CENTRAL NEW MEXICO. SOME
OF THIS MOISTR WILL CONTINUE ADVECTING NORTH AND MERGE WITH THE
ELONGATED TROUGH THAT WAS OVR THE CWA. THE LATEST RUC CONTINUED WITH
THE LOW/MID LVL MOISTR ACRS REGION AND THE -SN SHUD PERSIST THROUGH
THE MORNING HOURS.
AFTER ANALYZING THE MODELS THE ETA APPEARED TO FORECAST THE UPR LVL
TMPS AND HGHTS SLIGHTLY BETTER THAN THE AVN AND THE WETTER NGM. THE
INTENSE MID LVL LOW OVER NEW MEXICO WILL SLOWLY DRIFT ENE INTO
OKLAHOMA BY SATURDAY EVENING. SFC WINDS HAVE BEEN BELOW THE WINDY
CATEGORY MAINLY BECAUSE OF THE LOCATION OF THE LOW BEING FURTHER
SOUTH THAN THE MODELS FORECAST. BUT DURING SATURDAY THE WINDS SHUD
BEGIN TO INCREASE AND BECOME WINDY AS THE LOW INCHES CLOSER TO THE
CWA AND WILL MORE THAN LIKELY ISSUE A WIND ADVISORY TODAY.
AS THE -SN PERSISTS THROUGH SATURDAY SOME ACCUMULATION IS LIKELY.
SOME BLOWING OF SNOW IS ALSO PROBABLE WHERE SNOW BEGINS TO ACCUMULATE
AND MAY GO WITH A SNOW ADVISORY TODAY MAINLY SOUTH OF A WRAY
COLORADO/GLD/GOVE LINE. WITH THE CLOUD COVER TMPS SHUD BE SLOW TO
RECOVER AND REMAINING MAINLY IN THE 30S ACRS THE REGION.
DRIER MID LVL AIR WILL BEGIN TO MOVE INTO THE FA FROM THE NORTH
LATE SATURDAY. LOW LVL MOISTR WILL ALSO BEGIN TO DIMINISH DURING THE
NIGHT ALTHOUGH THERE MAY BE LINGERING SNOW SHOWERS ACRS THE EXTREME
S AND E CWA. IN ADDITION PRESSURE GRADIENTS SHUD CONT TO REMAIN
TIGHT ACRS THE C/E FA AND BREEZY CONDITIONS SHUD PERSIST.
5H/HGHTS BEGIN TO INCREASE FOR SUNDAY AND AFTN TMPS SHUD BEGIN TO
REBOUND. ALSO SFC WINDS WILL DECREASE AS THE STRONG MID LVL LOW
MOVES INTO THE LOWER MISSISSIPPI VALLEY.
THE EXTENDED HAS A WEAK RIDGE MOVING ACRS THE TRI-STATE AREA
MONDAY AND TUESDAY WITH DRY CONDITIONS PREVAILING. ANOTHER
DISTURBANCE WILL APPROACH THE REGION WEDNESDAY AND BRING OUR NEXT
CHANCES OF PCPN.
.GLD...SN/BLSN ADVISORY WEST AND SOUTH OF A LINE FROM WRAY
COLORADO/GLD/GOVE TODAY. ALSO A WINTER WEATHER ADVISORY FOR THE
REMAINDER OF THE CWA TODAY.
02
ks
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
325 PM CST SAT DEC 4 1999
WATER VAPOR LOOPS OVERLAYED WITH RUC 250 MB WIND SPEED SHOW THE
UPPER LOW NOW MOVING ENE AS THE CORE OF 90 KNOT AND GREATER WINDS
ARE NOW ONLY ON THE EAST SIDE OF THE TROUGH. STRONG DYNAMICS AND
ASSOCIATED UVV ALONG WITH PLENTIFUL MOISTURE AND INSTABILITY ARE
AIDING THE STRONG TO LOCALLY SEVERE THUNDERSTORMS IN THE SQUALL LINE
OVER NE TX. A MOISTURE FEED FROM THE SE GULF TO SE LA IS BECOMING
PINCHED OFF AT THE MOMENT AS THE MONSTER HIGH PRES TO OUR EAST
CONTINUES TO MAKE ITS INFLUENCE KNOWN...HOWEVER...A FEW SHOWERS
PERSIST BETWEEN LAKE PONTCHARTRAIN AND KMCB.
WINDS HAVE BEEN QUITE TRICKY WITH SOME LAND STATIONS UNDER 10 MPH
WHILE A FEW REPORT 15 TO 20 MPH WITH HIGHER GUSTS. THE SAME IS TRUE
IN THE COASTAL WATERS WITH SOME NEAR SHORE CMAN/BUOY STATIONS DOWN
AROUND 15 KNOTS WHILE OTHER LOCATIONS HOWL AS HIGH AS 30 KNOTS.
VARYING CYCLES OF INSTABILITY DUE TO THE LARGE TEMPERATURE AND CLOUD
COVER DIFFERENCES BETWEEN STATIONS IS LIKELY CAUSING THIS
VARIABILITY OF WIND SPEED. ANALYZED PRESSURE GRADIENT SUPPORTS AN
AVERAGE WIND SOMEWHERE IN THE MIDDLE OF REPORTED VALUES.
THE MODELS ARE WELL INITIALIZED AND IN GOOD AGREEMENT. WILL LEAN A
BIT TOWARDS THE ETA SINCE IT HAS HAD THE BEST PERFORMANCE AS OF
LATE. UPPER LOW OVER NW TX WILL SLOWLY FILL AS IT MOVES ENE TO THE
LOWER OH VALLEY MON MORNING WITH ASSOCIATED TROUGH BECOMING MORE
POSITIVELY TILTED. COLD FRONT SHOULD ENTER WESTERN SECTIONS OF SW MS
AND E CENTRAL LA AROUND 6 AM SUNDAY...CONTINUE EAST TO HANCOCK
COUNTY MS-GRAND ISLE LINE AROUND NOON...AND EAST OF JACKSON COUNTY
MS AND THE MOUTH OF THE MS RIVER BY 3 OR 4 PM SUNDAY.
A LINE OF SHOWERS/THUNDERSTORMS IS EXPECTED TO CONTINUE AHEAD OF THE
FRONT WITH ONLY SLIGHT ADJUSTMENTS TO POPS NEEDED. THUNDERSTORMS
SHOULD BE NON-SEVERE IN OUR WARNING AREA UNLESS THINGS GET GOING IN
S CENTRAL LA TONIGHT. WILL PRETTY MUCH END MENTION OF RAIN WITHIN AN
HOUR OR SO OF FRONTAL PASSAGE. DRY SLOT WILL LIKELY DECREASE CLOUDS
DURING THE AFTERNOON ON SUNDAY OVER THE NW HALF OF AREA WITH
REMAINDER OF AREA BECOMING MOSTLY CLEAR SUNDAY NIGHT. WRAP AROUND
CLOUDS LOOK LIKE THEY SHOULD STAY NORTH OF AREA SUNDAY NIGHT/MONDAY.
MUCH COOLER AIR WILL INVADE SUN NIGHT AND MONDAY AND WILL STAY CLOSE
TO FWC NUMBERS IN THOSE PERIODS. EXTENDED FORECAST LOOKS DRY WITH A
WARMUP ON WEDNESDAY BEFORE NEXT SYSTEM BRINGS RAIN CHANCES BACK ON
THURSDAY.
MCB 60/63/39/55 7600 BTR 61/64/41/55 7500
MSY 63/68/45/56 5610 BIX 66/70/46/57 3710
.NEW...SMALL CRAFT ADVISORY KPQL-ATCHAFALAYA RIVER.
LA...NONE.
MS...NONE.
22
FXUS64 KSHV 042109 la
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
937 PM EST SAT DEC 4 1999
UPSTREAM RADARS SW OF THE CWA SHOW A GROWING AREA OF RAIN MAKING
STEADY PROGRESS NE TOWARD NRN AND CENTRAL LOWER MI. SEVERAL TYPES OF
LIFT ARE DRIVING THIS AREA OF PRECIP. SOME ISENTROPIC ASCENT WAS
NOTED ON THE 295K SFC...AS WELL AS INCREASING 850-700 MB
FRONTOGENETIC FORCING AND Q-VECTOR CONVERGENCE. ALSO...LATEST RUC IS
SUGGESTING SIGNIFICANT STRENGTHENING OF A 500 MB JET MAX BETWEEN 02Z
AND 10Z...INCREASING DIVERGENCE ALOFT SPECIFICALLY IN THE RRQ OVER
NRN AND CENTRAL LOWER MI SW INTO THE SRN HALF OF LAKE MI TO THE CHI
AREA. RUC CROSS SECTIONS ARE SHOWING TOTAL SATURATION OVERNIGHT AS
THIS SYSTEM PROGRESSES NE INTO THE REGION. LATEST RUC HAS ALSO
SLOWED THE FRONT BY ABOUT 2 TO 3 HOURS...WHICH WILL NOT ONLY KEEP
PRECIP IN OUR CWA LONGER...BUT WILL ALSO SLOW TIMING OF CAA BEHIND
THE FRONT. THIS SEEMS REASONABLE BASED ON THE SPEED OF THE FRONT
THUS FAR...WHICH HAS TENDED TO BE A BIT SLOWER THAN PROGGED.
WILL UPDATE NRN LOWER MI ZONES TO GO WITH CATEGORICAL POPS
OVERNIGHT...BUT WILL KEEP SCT SHRA FOR ERN UPR MI AS THAT AREA WILL
BE ON THE FRINGE OF THE BETTER LIFT AND MOISTURE. HAVE ALSO DECIDED
TO KEEP PRECIP ALL LIQUID OVERNIGHT BASED ON PROJECTED TIMING OF THE
FRONT AND CAA BEHIND IT. WILL ALSO HAVE TO ADJUST THE SECOND PERIOD
FORECAST TO MENTION RAIN CHANGING TO SNOW DURING THE MORNING FOR
MOST OF THE CWA.
.APX...NONE.
EME
FXUS63 KDTX 050217 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS
836 PM EST SAT DEC 4 1999
...UPDATE FORECAST TO OCCASIONAL RAIN WITH AREAS OF FOG ALL CWA...
LATEST COMBINATION OF SATELLITE AND RADAR COMPOSITE INFO SHOWS AREA
OF RAIN ASSOC WITH JET COUPLING/DPVA WITH STRONG EXITING
SHTWV/OPENING UPPER LOW/MOISTURE CONVERGENCE ETC... IS SPREADING INTO
MOST OF CWA AT 01Z. COMBINATION OF THICKNESS COOLING AND GOOD UPPER
DYNAMICS WILL ASSURE A LONG PERIOD OF RAIN OVERNIGHT AS THE RAIN
BECOMES MORE WIDESPREAD. MOST AREAS HAVE 1 TO 3 MILES OF VIS IN
FOG... BUT WITH RAIN MOVING IN FEEL FOG WILL NOT GET DENSE ENOUGH
FOR A FOG ADVISORY.
LATEST SURFACE DATA INDICATES RUC TRACK BETTER THAN 12Z MODEL RUNS
AND THAT WOULD TAKE STORM TRACK FARTHER N THAN SUGGESTED BY 12Z
MODELS. THIS LIKELY WILL IMPACT HOW LONG IT RAINS AND WHEN AND IF
IT TURNS TO SNOW... BUT THIS CAN BE ADDRESSED BY MID NIGHT
FORECASTER.
SINCE CURRENT ZONE WORDING IS PERIODS OF RAIN DEVELOPING... WILL
FORECAST PERIODS OF RAIN WITH AREAS OF FOG FOR ALL OF CWA. OVER NRN
PART OF CWA... FCST IS RAIN LIKELY BUT WILL PUT SAME THERE TOO SINCE
RADAR RETURN CONTINUITY SHOWS RAIN ALREADY DEVELOPING THERE AND WITH
A FARTHER N TRACK... IT WILL RAIN THERE TOO.
.GRR...NONE.
WDM
FXUS63 KAPX 050047 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1050 PM EST SAT DEC 4 1999
WV IMAGERY THIS MORN SHOWS SHORTWAVE CROSSING LAKE WINNIPEG AND DEEP
TROF OVER SW CONUS...RESULTING IN CONTINUED MOIST SW FLOW INTO THE
UP. MOISTURE CONTINUES TO BE QUITE SHALLOW WITH 12Z KINL SOUNDING
SHOWING SUBSIDENCE INVERSION AROUND 800MB. KGRB SOUNDING SIMILAR
WITH SUBSIDENCE INVERSION AT 750MB AND SATURATED AIR BELOW. CANADIAN
SHORTWAVE SUPPORTS COLD FRONT/WIND SHIFT CURRENTLY MOVING THROUGH
EASTERN MN. WINDS BEHIND THIS LINE HAVE BEEN GUSTING >20KTS UNDER
TIGHTER PRESSURE GRAD. WINDS OVER OUR REGION CONTINUE TO BE QUITE
LIGHT UNDER MINIMAL PRESSURE GRAD WITH WIDESPREAD FOG AND CIGS BLO
010. DEW POINTS LOWER BEHIND FRONT (<25F) COMPARED WITH CURRENT
VALUES OF 35-40F OVER FA.
RUC INITIALIZES SFC PRESSURE FIELD OK...BUT UNDERDOING WINDS BEHIND
FRONT...COMPARED WITH 14Z METARS IN N DAK AND MN. THIS SHOULD NOT BE
A PROBLEM FOR THE AFTERNOON...SINCE STRONGEST WINDS LAGGING BEHIND
THE FRONT. RUC GENERATES SOME LIGHT PRECIP IN WESTERN COUNTIES AS
700-300MB CONV INCREASES AHEAD OF SHORTWAVE...BUT BASED ON LIMITED
SHALLOW MOISTURE... UPSTREAM METARS AND WEAK 88D RETURNS... WILL
KEEP OUT ANY PRECIP. AREA METARS CONTINUE TO SHOW FOG WITH VIS
GENERALLY RANGING FROM 1/2 TO 3SM. SOLAR HEATING QUITE
LIMITED...WITH WIDESPREAD LOW OVC CONDITIONS ACROSS THE REGION. WILL
KEEP PATCHY FOG WORDING IN FOR THE AFTERNOON.
TEMPS LOOK GOOD... EXPECTING LITTLE INCREASE WITH THICK CLOUDS IN
PLACE.
.MQT...NONE.
JS
FXUS63 KAPX 041543 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1015 AM EST SAT DEC 4 1999
VISIBILITIES HAVE IMPROVED ACROSS CWA SUFFICIENTLY TO DROP MENTION
OF AREAS OF FOG FOR THIS MORNING. HOWEVER...WITH SOME LOCALES STILL
REPORTING VISIBILITIES IN 2 TO 3 MILE RANGE WILL ACCOUNT FOR BR IN
NOWCASTS.
ALTHOUGH A FEW SUNNY BREAKS EVIDENT ON VISIBLE LOOP...WILL CALL THE
REMAINDER OF THE DAY MOSTLY CLOUDY. BOTH RUC AND MESO-ETA INDICATE
CURRENT 925 MB RH FIELDS TO REMAIN UNCHANGED FROM CURRENT MOSTLY
CLOUDY CONDITIONS THROUGH THE EARLY AFTERNOON...WITH LOW LEVEL
MOISTURE TO INCREASE FURTHER LATER IN THE AFTERNOON.
.DTX...NONE.
OKEEFE
FXUS63 KMQT 041047 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
514 AM CST SAT DEC 4 1999
VRY CHALLENGING FCST THIS AM FOR ALL FCST PRDS. LATE WITH AFD AS IT
TOOK AWHILE TO PACKAGE FCST IN ICWF. AFTER MISSING WELL NEEDED RAIN
IN MANY PLACES ON FRI IT LKS LK ALL OF CWA WILL EVENTUALLY GET WET TDY.
RUC APPRS TO HAVE DECENT HNDL ON CONCENTRATION OF H3 DVRGNC WHICH
SEEMED TO ASSIST ROUND OF CNVTN OVR SW MO LAST NITE AND CONTS TO
ASSIST IN KEEPING RAINFALL TOGETHER AS LARGE BAND MVS NEWRD ACR SE
CWA. PROFILER DATA AND IR LOOP THRU 1030 UTC SHWS NOSE OF 80 KT JET
LIFTING NWRD THRU OK AFT ROUNDING BASE OF DEEPENING SYS WRN HI PLNS.
BOTH RUC AND LAST NITES ETA SHW ANOTHER AREA OF H3 DVRGNC COUPLED
WITH THIS FEATURE. MODELS KEEP BULK OF QPF OVR SRN CWA BUT WITH
AFOREMENTIONED DVRGNC CONCENTRATION AND TREND OF COOLING TOPS ACR
ERN KS THINK THAT ALL OF CWA ALG STATE LN GET WET THIS AM. WENT WITH
CATEGORICAL POPS IN W AND SRN ZNS AND LEFT LIKELY ACR NE CWA. MODEL
X-SECT DATA SUGGESTS UPRIGHT CNVTV POT TDY THRU TNGT SO LEFT CHC FOR
THNDR ALL ZNS. CD FNT THRU ALL BUT XTRM SE CWA SO DID NOT ALLOW FOR
MUCH TEMP RISE TDY. CRNT FCST HAD GOOD HNDL ON TEMPS TDY SO MADE LTL
CHGS.
STLT LOOPS SHWS DEFORMATION ZN ACTUALLY BREAKING UP AS OF 1030 UTC
AFT DUMPING SVRL INCHES OF -SN OVR NM AND PLNS OF CO. CONCERNED THAT
WITH LTL OR NO TROWAL SIGNATURE IN POT TEMP FIELDS PRESENT ATTM OR
FCST BY MODELS NXT 24-36 HRS HAVE A HUNCH THAT STG DEVELOPMENT OF
COMMA FEATURE AS SYS MVS INTO PLAINS MAY BE SOMEWHAT INHIBITED. ETA
SHWS SOME WEAK TROFING OF WRM ALF OVR ERN NE BUT NOT REAL STG CNVGNC
OF QS COUPLED WITH IT. NEVER THE LESS ALL MODELS ADVANCE UPPER LO AND
AFOREMENTIONED DEFORMATION ZN TO NE ACR KS LTR TDY AND TNGT.
ALTHOUGH SLIGHT VARIATIONS WITH EACH MODELS PLACEMENT OF CNVGNC OF
Q, QN, QS FIELDS ALL FCST TO ENOUGH LIFT OVR NE KS/NW MO LATE TNGT
AND SUN AM COMBINED WITH CHILLY PAC AMS TRAILING STORM SYS TO
TURN RA TO SN AS FAR E AS NW MO SHRTLY AFT MDNT. FCST SNDG DATA SHWS
THAT CRNT ZFP NOT TOO FAR OFF MARK SO MADE LTL CHGS IN PCPN TYPE
WORDING AND TIME OF CHG OVR. AWIPS SPEC HUMIDITY FIELDS FOR MID
TROPOSPHERE SUGGEST MOD AMT OF MSTR TO BE POTENTIALLY WRUNG OUT IN
CD QUAD OF SYS. POTENTIAL EXIST FOR SVRL INCHES OF SN ACR PROBABLY
NW CWA BUT SINCE IT DOES NOT LOOK LIKE POT HVY SN EVENT OR WINTER
STORM CRITERIA DID NOT ISSUE WATCH FOR LATE TNGT/SUN. WILL SEND OUT
SPS HIGHLIGHTING POTENTIAL FOR FIRST SNOWFALL OF SEASON AFT LONG PRD
OF UNSEASONABLY WRM WX.
SUN LKS LIKE BLUSTERY CHILLY DAY WITH TEMPS STDY OR FALLING WILL
CARRY LIKELY POPS ALL ZNS AND ADJUST PCPN TYPE FM W TO E. ENDED PCPN
IN W SUN NITE BUT WILL LINGER ERN ZNS.
.EAX...
KS...NONE.
MO...NONE.
BODNER
mo
SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
845 PM CST SAT DEC 4 1999
SNOWFALL REPORTS FROM SE CWA HAVE YIELDED UP TO AN INCH ON GRASSY
SURFACES. AIR TEMPS REMAIN JUST ABOVE FREEZING DESPITE DEW POINTS
FROM 27 TO 30 DEGREES. RUC SHOWS ONLY LIGHT AMOUNTS FOR NEXT 4
HOURS OR SO AND RADAR RETURNS ARE LESS IMPRESSIVE THAN EVER. UPPER
AIR ANALYSIS/SATELLITE SHOWS SYSTEM TO BEGIN ACCELERATING NEWD.
ROAD CONDITIONS IN ADVISORY AREA ARE WET ATTM. MAY EVENTUALLY SEE A
LITTLE SNOW STICK OR AT LEAST SEE ICING AS TEMPS DROP...BUT DOES NOT
APPEAR TO BE TOO SIGNIFICANT. THEREFORE WILL CANCEL ADVISORY AND
MENTION POSSIBLE SLICK SPOTS AND ENDING OF PCPN.
IN THE NORTHWEST CWA...SKIES HAVE CLEARED AND WINDS DROPPING TO
AROUND 10 KNOTS. DEW POINTS IN THE TEENS AND FALLING. WILL LOWER
MIN TEMPS THERE.
.GID...NONE.
DROZD
FXUS63 KOAX 042031 ne
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
230 PM CST SAT DEC 4 1999
FORECAST CHALLENGES -- SNOWFALL AMOUNTS ACROSS FAR SERN NEB AND
PRECIPITATION CHANCES FARTHER N.
SYNOPSIS -- LATEST WATER VAPOR IMAGERY SHOWED A STRONG...CLOSED
UPPER LOW IN THE VICINITY OF KCDS IN NWRN TX...SLOWLY LIFTING NEWD.
300MB PROFILER WINDS ACROSS CNTRL OK AND S CNTRL KS HAVE INCREASED
MARKEDLY OVER THE PAST COUPLE OF HOURS...SIGNALING A CONTINUED NEWD
EJECTION OF THIS LOW. MEANWHILE...REGIONAL RADAR COMPOSITES AND
SURFACE OBSERVATIONS INDICATED MAINLY LIGHT RAIN ACROSS THE ERN HALF
OF KS...WITH A SLOW NWD TREND IN THE PRECIPITATION SHIELD.
FORECAST -- AS MENTIONED IN THE EARLIER DISCUSSION...THE 12Z SHORT
RANGE MODELS HAVE ALL COME INTO GOOD AGREEMENT ON THE HANDLING OF
THIS STORM SYSTEM...WITH A MORE SRN TRACK FAVORED (WHICH WAS CLOSE
TO PREVIOUS ETA RUNS). THUS...THE AREA FOR ACCUMULATING SNOWFALL
OVERNIGHT APPEARS NOW TO BE LIMITED TO FAR SERN NEB. RUC FORECAST
SOUNDINGS FOR THE FNB AREA INDICATE SOME DRY AIR IN THE LOW LEVELS
THIS AFTERNOON AND THIS WILL HAVE TO BE OVERCOME BEFORE MEASURABLE
PRECIPITATION CAN OCCUR. LARGE SCALE FORCING WILL CONTINUE INCREASE
ACROSS THE AREA THIS EVENING...WITH SATURATED LOW LEVELS FORECAST BY
03Z. TEMPERATURE PROFILES FROM ALL SHORT RANGE MODELS SUPPORT
LIQUID PRECIPITATION THROUGH 04Z...THEN A MIX FROM 04Z-08Z...AND
THEN ALL SNOW THEREAFTER. FARTHER N...TEMPERATURES WILL SUPPORT ALL
SNOW...BUT DRY AIR ENTRAINMENT IN THE LOW LEVELS AND MINIMAL UPWARD
FORCING SHOULD LIMIT SNOWFALL POTENTIAL.
DEEP-LAYERED QG FORCING AND 300K ISENTROPIC LIFT WILL BE MAXIMIZED
BY 12Z SUNDAY OVER FAR SERN NEB WITH A SHARP GRADIENT IN MID LEVEL
LAPSE RATES...RANGING FROM AROUND 6 DEG C/KM ACROSS SERN NEB TO
GREATER THAN 8 DEG C/KM OVER ECNTRL KS AND WCNTRL MO. THIS WOULD
INDICATE THE POTENTIAL FOR HEAVY SNOWFALL...BUT FORECAST SOUNDINGS
FROM THE ETA...NGM AND AVN ALL ENTRAIN CONSIDERABLE DRY AIR INTO THE
LOW LEVELS DURING THIS TIME FRAME INTO SERN NEB. CURRENT
INDICATIONS ARE THAT THERE WILL BE A TIGHT SNOWFALL GRADIENT FROM
THE FNB AREA SWD. AT THIS TIME...WE HAVE DECIDED THAT THE HEAVY
SNOWFALL POTENTIAL WILL BE S OF THE CWFA...BUT POTENTIAL SNOWFALL
AMOUNTS OF UP TO 4 OR 5 INCHES... COMBINED WITH STRONG NLY
WINDS...WARRANT A WINTER WEATHER ADVISORY FOR PAWNEE AND RICHARDSON
COUNTIES TONIGHT AND EARLY SUNDAY.
SNOWFALL SHOULD BEGIN TO TAPER OFF TOMORROW MORNING IN THE FAR SE
WITH CLEARING SKIES THROUGH AFTERNOON ELSEWHERE. WINDY CONDITIONS
SHOULD CONTINUE INTO AFTERNOON ACROSS THE S...BUT THE WINDS WILL
WEAKEN CONSIDERABLY IN THE N. WE HAVE GONE WITH A BLEND OF FAN AND
FWC TEMPERATURES ON HIGHS. SUNDAY NIGHT...CLEARING SKIES AND LIGHT
WINDS SHOULD ALLOW FOR GOOD RADIATIONAL COOLING CONDITIONS AND WE
HAVE GONE BELOW GUIDANCE IN ALL AREAS. ON MONDAY...A NRN STREAM
SHORTWAVE SHOULD SPREAD HIGH LEVEL CLOUDS ACROSS THE AREA WITH A
SHARPENING LEE TROUGH TO THE W. AGAIN...A BLEND OF FAN AND FWC
TEMPERATURES WERE USED.
IN THE EXTENDED...WE FEEL THAT THE LESS AMPLIFIED AND MORE
PROGRESSIVE ECMWF IS MORE CORRECT THAN THE MRF SOLUTION WITH A
CONTINUED CHANCE OF PRECIPITATION ON WEDNESDAY.
.OMA...WINTER WEATHER ADVISORY TNGT/ERLY SUN NEZ092>093
MEAD
FXUS63 KGID 042014 ne
SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
215 PM CST SAT DEC 4 1999
-RA/SN CONT TO THREATEN THE SRN EDGE OF GID CWA THIS AFTN AS UPR LOW
SPINS ACRS THE TX PANHANDLE. SFC LOW WAS CNTRD OVR ERN OK AT 18Z
WITH DRY AIR/CLR SKIES ON THE NWRN EDGE OF THE PERIMETER.
18Z RUC CONTS TO PROG HALF DECENT ISENTROPIC LIFT ON THE 290/295K
SFCS THRU 03Z UNDR DEFORMATION ZONE OVR SRN EDGE OF CWA. WL THUS
REPLACE WATCH WITH WINTER WX ADVISORY WITH ONLY SLIGHT SHIFT IN
COUNTIES. DRY AIR ADVECTING IN AND DECREASING LIFT WL NOT SUPPORT
SIGNIFICANT ACCUMULATIONS FOR OUR AREA. WL KP MENTION OF A CPL
INCHES FOR TNGT WITH WINDY CONDITIONS FOR THAT AREA...AND WL TAPER
TO FLURRIES BY SUNRISE.
SUNNY SKIES FOR MOST OF CWA ON SUN WITH DECREASING WND...SOME
WEAK DOWNSLOPE WL AID TMP RECOVERY. WL FOLLOW THE MOS TREND UPWARD.
IN LATTER PDS AND EFP...GENLY ZONAL FLOW WL KP CONDITIONS DRY
UNTIL NXT SYS EMERGES FM THE ROCKIES ON WED PRVDG RA/SN THREAT. WL
ALSO MENTION SN ON THU...ALTHOUGH CURRENT TIMING WOULD END SPPRT
EARLY.
.GID...WINTER WEATHER ADVISORY FOR NEZ086...087 AND FOR KSZ007...
017...018...019.
09
FXUS63 KLBF 041925 ne
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
1000 AM EST SAT DEC 4 1999
CURRENT FCST LOOKS ON TRACK WITH MOSTLY SUNNY SKIES AND TEMPS
WARMING NICELY ON WSW FLOW. SFC RIDGE WILL REMAIN CENTERED JUST S OF
AREA INTO TONIGHT AND SIGNIFICANT CLOUDINESS WILL STAY W AND N. NGM
DOES SHOW AREA OF 80+ RH AT 250 MB SPREADING OVER ERN NC TODAY BUT
DID NOT VERIFY WELL WITH THIS FEATURE AT 12Z SO DISCOUNTED.
THICKNESS TECHNIQUES AND MORNING RAOBS SUPPORT HIGHS THIS AFTN IN
LOWER 70S WITH MID 60S OUTER BANKS. WILL ADJUST COASTAL PLAIN
ACCORDINGLY.
CWF: MOST OBS FROM W AROUND 15 KTS WITH DIAMOND SHOALS AN OUTLIER
NEAR 20. LATEST RUC AND MESOETA INDICATE WINDS 15-20 KTS THIS AFTN N
OF CAPE LOOKOUT AND WILL ADJUST FCST TO AT LEAST SOLID 15 KTS.
.MHX...NONE.
JBM
FXUS62 KILM 041501 nc
EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
940 PM CST SAT DEC 4 1999
LATEST SATELLITE IMAGERY SHOWING DRY SLOT MOVING ACROSS EASTERN
OKLAHOMA INTO WESTERN ARKANSAS. THEREFORE...ADDED SOME BECOMING
CLOUDY ACROSS SOUTHEAST ZONES AS LOW CLOUDS WRAPPING AROUND UPPER
SYSTEM MOVE BACK IN OVERNIGHT.
AS FOR PRECIPITATION...THINK THE THUNDER THREAT IS MAINLY OVER FOR
NOW WITH AREAS OF DRIZZLE LIKELY ACROSS THE FA THROUGH TOMORROW
MORNING. GIVEN LACK OF NEW MODEL DATA HAVE LOOKED AT LATEST RUC FOR
GUIDANCE ABOUT POSSIBILITY OF SNOW. WATER VAPOR NOW LOOKING LIKE
UPPER LOW IS MOVING MORE NORTHEASTERLY WHICH SHOULD HELP KEEP SNOW
OUT OF OUR CWA. HOWEVER...GIVEN PROXIMITY OF SNOW REPORTS IN OBS AS
CLOSE AS ICT... HAVE ADDED THE POSSIBLITLY FOR SOME FLURRIES IN FAR
NORTHWEST ZONES OVERNIGHT.
REMAINDER OF FORECAST UNCHANGED AT THIS TIME. UPDATE COMING SHORTLY.
HOWIESON
FCSTID = 44
.TUL...
AR...NONE.
OK...NONE.
FXUS64 KOUN 050339 ok
AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST
SOUTH DAKOTA AND WEST CENTRAL MINNESOTA
NATIONAL WEATHER SERVICE ABERDEEN SD
200 PM CST SAT DEC 4 1999
AVN/ETA NEARLY IDENTICAL AND WILL BASE PACKAGE ON BLEND OF THESE.
NICE H50 RIDGE BUILDING IN ADVANCE OF WEST COAST STORM. THE RESULT
FOR MY AREA IS HIGH PRESSURE THROUGH MONDAY. WITH GOOD CLEARING AND
LIGHT WINDS TONIGHT...LOW TEMPERATURES WILL BE INTERESTING. MOST
DEWPOINTS ARE IN THE LOW 20S RIGHT NOW...BUT ETA/RUC MODEL SOUNDINGS
SHOW GOOD DRYING THROUGHOUT THE NIGHT. FWC/FAN/FMR ALL SUGGEST UPPER
TEENS OVERNIGHT...BUT WILL DROP THESE TEMPS A FEW DEGREES AREA WIDE
WITH GOOD RADIATION AFTER SUNSET AND A LONG NIGHT TO COOL. RIDGE
AXIS MOVES THROUGH SUNDAY 12-15 UTC PER AVN/ETA...SO WILL GO WITH
SOUTHERLY WINDS. SINCE AIR IS SO DRY...BELIEVE A 30 DEGREE DIURNAL
CHANGE IS NOT OUT OF THE QUESTION AND HAVE RAISED SUNDAYS HIGHS WELL
ABOVE GUIDANCE AND THE PREVIOUS PACKAGE. SUNDAY NIGHT WILL BE COOL
AGAIN...AND WITH CLEAR SKIES POTENTIAL FOR LOW TEENS EXISTS. HOWEVER
BELIEVE THE WINDS WILL KEEP UP A WHILE IN THE EVENING...AND SO LOW
TEMPS ON SUNDAY SIMILAR TO SAT NITES LOWS. CURRENT WEST COAST STORM
MAKES BRIEF APPEARANCE AS AN OPEN WAVE ON MONDAY...BUT LIKE MOST OF
THE RECENT WAVES...HAS WEAKENED AND DRIED AS IT MOVES ACROSS THE
ROCKY MTNS....THUS MONDAY LOOKS TO HAVE A FEW MID/HIGH CLOUDS
PRESENT...BUT ONLY MENTIONED IN NORTHERN CWA. HIGHS ON MONDAY SHOULD
BE A FEW DEGREES WARMER THAN SUNDAY...BUT NOT BY MUCH.
...EXTENDED FORECAST DISCUSSION...
NOGAPS AND MRF CONTINUE TO INDICATE SPLIT FLOW THRU NEXT THURSDAY.
BOTH MODELS PROG NORTHERN STREAM SHORTWAVE TO DIG SSE TOWARDS THE
SOUTHERN PLAINS. THE MRF PROGS THE SFC LOW TO BE FURTHER SOUTH THAN
THE PREVIOUS RUN. AM BEGINNING TO GET CONCERNED THAT THIS SYSTEM
COULD BYPASS OUR AREA TO THE SW BY GETTING CAUGHT UP IN THE SOUTHERN
BRANCH. HOWEVER...WILL CONTINUE THE CHC OF SNOW SINCE THE MRF STILL
PROGS AN INVERTED TROF MOVING ACROSS OUR AREA ON WED. IN ADDITION...
THIS SFC TROF MIGHT BE ABLE TO TAP A LITTLE GULF MOISTURE. MRF PROG
534-540 THICKNESSES ON WED. THE NEXT MODEL RUN SHOULD SHED MORE
LIGHT ON THIS PROBLEM. MEANWHILE...A WARM UP SHOULD COMMENCE EARLY
NEXT WEEK IN ADVANCE OF SFC LOW. TEMPS COOL DOWN AGAIN AS THE SFC
LOW MOVES SE ALLOWING SOME CAA INTO THE AREA. WENT CLOSE TO ABOVE
NORMAL FMR GUIDANCE TEMPS.
.ABR...NONE.
HARDING/GUERRERO
FXUS63 KUNR 041720 sd
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN ANGELO TX
827 PM CST SAT DEC 4 1999
THE LATEST RUC CONFIRMS WHAT SATELLITE TRENDS NOW SHOW...THAT
SUBSIDENCE AND DRYING ARE DOMINATE ACROSS WEST CENTRAL TEXAS THIS
EVENING. THE UPPER LOW HAS LIFTED INTO CENTRAL OKLAHOMA...AND WILL
CONTINUE TO PULL AWAY OVERNIGHT. THE WRAP AROUND STRATUS ROTATING
THROUGH THE FORECAST AREA CONTINUES TO SHRINK IN SIZE. REASON
BEING...STRONG Q-VECTOR DIVERGENCE IN THE 850-500 MB LAYER...PER RUC.
WE/LL DROP MENTION OF PCPN IN THE BIG COUNTRY. ALSO PREFER PARTLY
CLOUDY CONDITIONS MAINLY NORTH HALF. WINDS WILL GRADUALLY DIMINISH
TO 10 TO 20 MPH BY MORNING AS PRESSURE GRADIENT WEAKENS. ZONE UPDATE
ALREADY HIT THE STREETS.
.SJT...CAUTION ON AREA LAKES.
17
FXUS64 KEWX 050228 AMD tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIDLAND TX
250 PM CST SAT DEC 4 1999
AN INTERESTING DAY WEATHER WISE AROUND THE REGION. UNFORTUNATELY
MOST OF THE PRECIP REMAINED NORTH AND EAST OF THIS PARCHED REGION.
FOR THE START...500 MB UPPER ANALYSIS INDICATED AN UPPER LEVEL SYSTEM
OVER EASTERN NM. THE LOWEST HEIGHTS AT THIS LEVEL WERE AROUND AMA...
BUT WE HAD A SW FLOW OF AROUND 75 KNTS...BRINGING THE MAIN LOW CENTER
BETWEEN CVS AND HOB. THE FORECAST MODELS INITIALIZED THIS FEATURE
FINE. VISIBLE SATELLITE ANIMATION INDICATED A CLASSIC COMMA SHAPE
SYSTEM MOVING EASTWARD ACROSS THE SOUTH PLAINS. EVIDENCE OF SNOW
COVER WAS NICELY NOTED EASTERN WY...EASTERN CO...AND W/CENTRAL NM.
19Z ANALYSIS HAS THE MAIN SURFACE LOW OVER SE OK...WITH A TROUGH
EXTENDING TO WEST TX. IT WAS ASSOCIATED WITH THE WIND SHIFT DURING
THE LATE MORNING HOURS FOR OUR NORTHERN AND CENTRAL COUNTIES.
AN AREA OF LOW CLOUDS WITH A WAVY/MOTTLE APPEARANCE SUGGESTING IN-
STABILITY HAD FORMED OVER THE PERMIAN BASIN/TRANS PECOS REGION NORTH
OF THE DAVIS MTNS AND BIG BEND. MSAS ANALYSIS AND RUC INITIALIZATION
INDICATED LOW LEVEL UPPER MOTION...PARTIALLY INDUCED FROM THE UPPER
SYSTEM EXITING AND STRONG COLD AIR ADVECTION SEEMS TO BE THE CAUSE.
THIS GO AROUND...WILL NOTE A SLIGHT CHANCE OF RAIN/SNOW MIX OVER THE
NORTHERN PERMIAN BASIN AS THIS SYSTEM EXITS THE REGION. WITH SURFACE
WINDS MORE FROM THE NORTH THAN NE...UPGLIDE AT THE LOWER LEVELS WILL
NOT BE AS PREVALENT THUS EXPECT CLEARING OF SKY COVER LATER TONIGHT.
A RETURN OF RATHER COLD TEMPS OVERNIGHT LOW TEMPS CAN BE EXPECTED.
FOR MOST AREAS TONIGHT...WILL COOL TEMPS BELOW FREEZING (EXCEPT FOR
TERRELL COUNTY AND THE RIO GRANDE VALLEY). HIGH TEMPS ON SUNDAY WILL
REBOUND SOME WITH MORE SUNSHINE BUT SHOULD REMAIN BELOW SEASON NORMS
(LOCALLY 61/33).
FOR THE EXTENDED...WILL KEEP A DRY FORECAST GOING. THE 72 HOUR AVN
SHOWS A SYSTEM WILL DIG SOUTHWARD TOWARD THE BAJA TUES. THIS WAS
AGREEING WITH THE NAVY MODEL SHOWING A GOOD TRAJECTORY FOR PRECIP
HERE. HOWEVER WITH THIS RECENT WEATHER REGIME...HAVE SEEN TOO MANY
SYSTEMS LIKE THIS NOT PRODUCE VERY MUCH FROM THE EXTENDED. THE
PREVIOUS MRF RUN WAS KEEPING IT DRY TOO...WITH MACHINE NUMBERS IN
THE 10-15 POPS RANGE THURS.
WILL REMAIN CLOSE TO GUID IN FIRST GUESS BELOW. WILL GO SLOWER THAN
MACHINE NUMBERS FOR WARM-UP ON MONDAY. COMMENTS R WELCOMED.
MAF 25/55/22/62 -000
LSA 23/52/21/59 -000
E41 28/54/25/63 -000
6R6 31/57/27/63 -000
MRF 18/50/16/59 0000
CNM 22/53/22/62 -000
.MAF...
TX...NONE.
NM...NONE.
BOYD
FXUS64 KHGX 042046 tx
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
955 AM CST SAT DEC 4 1999
SHOWERS GOING FULL TILT OVER THE WESTERN CWA WITH A FEW EMBEDDED
THUNDERSTORMS. MORNING SOUNDING PAINTED A GRIM WEATHER SCENARIO FOR
TODAY...CRP-HELICITY >150/EHI >3.0/MODIFIED CAPE >1500 WITH A CAP OF
1.5C. USING THE CRP SOUNDING ANY OF THE STORMS THAT SHOW AN EASTWARD
MOVEMENT AND SLOWING WOULD BE GOBBLING UP THE INFLOW AND WILL
WARRANT VERY CLOSE ATTENTION. LCH SOUNDING HAD LESS CAP AND WEAKER
WIND FIELD. MODELS NOT DOING A GREAT JOB WITH THE PREFRONTAL TROUGH
THAT HAD GOTTEN WELL AHEAD OF THE FRONT AT 13Z. PREFRONTAL TROUGH
THROUGH ACT/AUS/COT FRONT STILL NORTH OF JCT/DFW LINE AT 15Z.
EXPECT THE FRONT TO ACCELERATE INTO SOUTHEAST TEXAS THIS AFTERNOON
AND EARLY EVENING. WE ARE FORECAST TO BE LONG ON CAPE BUT SHORTER ON
WIND SHEAR...THIS IS SUPPORTED BY THE CURRENT VWP. GREATER LAPSE
RATES AND DYNAMICS SHOULD BE IN N TX AND PERHAPS IN THE NORTHERN
ZONES THROUGH EARLY AFTERNOON...AND THEN ACTION WILL LIKELY SHIFT
QUICKLY SOUTHEASTWARD AROUND 2 OR 3 PM ... RUC DEPICTS SUBTROPICAL
JET COMING INTO PLAY OVER THE SOUTHEASTERN ZONES. ZONES CURRENTLY
CARRYING SVR/+RA IN WORDING AND DO NOT FORESEE ANY SIGNIFICANT
CHANGES OTHER THAN TO LOWER TEMPS IN NW/N ZONES WHERE ONGOING
PRECIP/CLOUD COVER SHOULD LIMIT THE TEMPERATURE RISE. WINDS OVER THE
WATER AND BIG ROLLING SWELLS WARRANT CONTINUED SCA...BUT THE SURFERS
MAY BE IGNORING THAT.
45/41/JACK
.HGX...SMALL CRAFT ADVISORY ALL WATERS.
PRELIMS...
CLL TB 075/041 057/032 062 42600
IAH TB 078/043 059/034 062 42740
GLS TB 075/052 059/043 062 42740
FXUS64 KCRP 041542 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
951 AM EST SAT DEC 4 1999
WK STORM SYS TO SCOOT BY TO THE NORTH ACRS SOUTHERN CANADA TDY...
WITH WK RIDGING (ALOFT AND AT SFC) MOVING IN FROM THE WEST EARLY
TONIGHT ACRS FA. FIRST H5 S/W...WITH ASSOCIATED ENHANCED AREA OF
RA...MOVED THROUGH SOUTHERN VT THIS MORNING. SECOND...AND WEAKER...
S/W TO MOVE ACRS FA THIS AFT FROM EASTERN ONT.
KTYX 88D STILL OUT AND NO BUFCAN...BUT IR SAT PIX SHWS WARMING TOPS
ASSOCIATED WITH NEXT BATCH OF POTENTIAL PCPN...TO THE NORTH OF LK
ONT...ATTM. RUC HAS LT PCPN PERSISTING INTO THIS AFT. WITH PLENTY OF
MOISTURE (AT H85 AND BLW) TO WORK WITH THIS AFT...FEEL BEST CHC FOR
ANY MEASURABLE RA WILL BE IN THE MTNS WITH ANY OROGRAPHY. WILL ONLY
ADD POPS TO THIS AFT/S FORECAST FOR THESE AREAS AND JUST MENTION SCT
SPRINKLES OR DRIZZLE ELSEWHERE.
WK H85 WAA PATTERN AHEAD OF TDY/S WK CANADIAN LO PRES SYS WITH
STRONGER WAA...AFT 06Z TONIGHT...AHEAD OF NEXT SYS MOVING ACRS GREAT
LKS REGION.
RUC/14Z LAMP SHOWING TDYS MAXS IN THE L-M40S WITH LT WNDS ACRS FA.
WILL PROLLY ADD PATCHY FG TO EASTERN VT ZONES.
WORKZONES AVBL IN A MIN OR TWO.
.BTV...NONE.
MURRAY
vt
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
250 AM CST SUN DEC 5 1999
CLOSED UPPER LOW LOCATED AT 06Z JUST NORTH OF TULSA PER SATELLITE
MOVING EAST NORTHEAST AT 20 MPH. DECENT DEFORMATION ZONE CAUSED
BY VIGOROUS CLOSED UPPER LOW EXTENDS BACK SOUTHWESTWARD FROM KSTJ TO
AROUND KICT. PRECIP IS SNOW WEST OF KMHK WITH MAINLY RAIN EAST AT 06Z
ALONG DEFORMATION ZONE. DRY SLOT HAS MOVED INTO SW MO WITH WARM
CONVEYOR BELT STILL STREAMING NORTH NORTHEAST AT 45-50 MPH WITH BACK
EDGE ALONG A KLIT TO KCOU TO KCID LINE. THIS IS WHERE MOST OF THE
HEAVIER PRECIP IS FOCUSED WHICH IS SLIDING EAST AT 15 MPH. STRONG
HEIGHT RISES BEHIND SYSTEM SUPPORT RAPID CLEARING AFTER UPPER LOW
MOVES WITH SURFACE AND UPPER RIDGE MOVING IN FROM ROCKIES. BREEZY
NORTH WINDS OVER CENTRAL PLAINS BRINGING GOOD CAA JUST BEHIND UPPER
LOW. LATEST 88D MOSAIC AT 08Z SHOWS SOME INTERACTION OF WARM
CONVEYOR BELT PRECIP WITH UPPER LOW ACROSS SE IOWA AND NE MO.
...TIMING END OF PRECIP WITH SNOW CHANGEOVER PRIMARY NEAR TERM
CONCERN...
NGM/ETA MODELS INITIALIZED BEST WITH UPPER LOW AND DEFORMATION ZONE
WITH ALL THREE MODELS HANDLING OTHER LARGER SCALE FEATURES WELL.
VERIFICATION DEFINITELY SHOWS NGM/ETA DOING MUCH BETTER THAN AVN
WITH DEFORMATION ZONE WITH LITTLE DIFFERENCE OF THIS FEATURE BY BOTH
MODELS WHILE AVN TOO BROAD WITH WETNESS. LATEST 06Z RUC ALSO
SUPPORTS ETA/NGM SOLUTION. SHORT TERM FORECAST TOOLS ALSO SUGGEST
DEFORMATION ZONE AFFECTING SOUTHERN 1/3 CWA AS IT MOVES EAST.
CHALLENGE WILL BE TIMING OF CHANGEOVER TO SNOW WITH ANY POSSIBLE
ACCUMULATIONS. LOCAL THRESHOLDS PER ETA SUPPORT LITTLE ACCUMULATIONS
WITH MAYBE AN INCH IN FAR SOUTHEAST ZONES OF IOWA AND FAR NE
MISSOURI. HOWEVER WITH THIS KIND OF VIGOROUS FEATURE AND PHASING OF
COLD AIR UNCERTAINTY SIGNIFICANT CHANCE FOR EARLIER CHANGEOVER WHICH
WILL NEED TO CLOSELY MONITOR UP TO AND BEYOND ZONE ISSUANCE.
NEAR TERM...THIS MEANS RAIN ENDING FAR NW ZONES BY DAYBREAK WITH
CLEARING SKIES AND BREEZY NW WINDS AND GOOD CAA FOR NEAR STEADY
TEMPS. WILL KEEP CHANCE POPS RUNNING JUST SOUTH OF THIS AREA THIS AM
WITH RAIN POSSIBLY CHANGING OVER TO LIGHT SNOW FLURRIES BEFORE
CLEARING THIS PM EXTENDING FROM FREEPORT TO IOWA CITY. NEXT RIBBON
OF COUNTIES WILL GO WITH LIKELY AM WORDING WITH A BRIEF PERIOD OF
SNOW POSSIBLE WITH LITTLE ACCUMULATION THEN PM CLEARING RUNNING FROM
STERLING TO QUAD CITIES TO FAIRFIELD. THEN...MOST SUSCEPTIBLE ZONES
ALONG SHEARING DEFORMATION ZONE SHOULD BE THE SOUTHERN ROW OF IOWA
COUNTIES AND TWO MISSOURI COUNTIES. HERE WILL GO CATEGORICAL WITH
OCCASIONAL WORDING AND ACCUMULATIONS OF INCH OR LESS AGAIN BASED ON
LOCAL STUDIES OF TEMPS AND DECAYING FORCING WITH SYSTEM. WILL LIMIT
MENTION OF SNOW FOR NW ILLINOIS ZONES DUE TO DELAYED COOLING OF TEMPS
FOR CHANGEOVER. FOR PM PORTION WILL HIT BREEZY AND TURNING COLDER
WORDING AS CLEARING KICKS IN WITH SOME LINGERING CHANCE POPS FAR SE
ZONES OF RAIN/SNOW. TEMPS WILL FOLLOW JUST ABOVE ETA 2M TEMPS WHICH
MEANS STEADY TO SLOWLY FALLING TEMPS TODAY WORDING.
QUIET AFTER FIRST PERIOD WITH FOLLOWING OF FWC/FAN BLEND WHICH ARE
CLOSE BEYOND FIRST PERIOD.
MINOR CHANGES TO PRECIP TODAY AND GROUPINGS.
EXTENDED PERIOD...LATEST MRF/UKMET/ECMWF BLEND SHOWS ANOTHER STORM
SYSTEM BY THURSDAY WITH SNOW WEST AND RAIN EAST. THIS COVERED IN
CURRENT PACKAGE WITH JUST MINOR ADJUSTMENTS. MAINLY DRY TUE/WED
AHEAD OF NEXT STORM SYSTEM.
PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE
CONTAINED WITHIN QUAD CITIES ZONE FORECAST.
DBQ EA 035/020 035/025 041 16200
CID BA 035/021 037/026 042 16200
MLI OA 037/025 038/028 045 16700
BRL OA 039/026 040/030 047 169-0
.DVN...
IA...NONE.
IL...NONE.
MO...NONE.
NICHOLS
FXUS63 KILX 050835 il
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
315 AM CST SUN DEC 5 1999
MAIN CONCERN IS SHORT TERM PORTION OF THE FORECAST. CHANGEOVER AND RESULTING
SNOW AMOUNTS ARE BIG QUESTION.
DEFORMATION ZONE SETUP WITH LIFT NEWRD WHILE MOVEMNT OF ENTIRE SYSTEM MOVG
EWRD. BIG HELP IS TREND OF LTST RUC WHICH APPEARS TO HANDLE DEF ZN WELL.
FOLLOWING RUC WULD GIVE BEST SNOW FM SWRN IA TWD KOTM. FIGHT WILL BE WITH
DRIER AIR INTO ST AKG WITH PULLING EWRD COMPNT. GOING FCST FM LAST NGT LOOKS
GD HWVR MAY EXTEND PCPN AS UPPER LO SLO TO PULL OFF. AFTER FIRST PD REST OF
FCST BACK TO "NORMAL" WITH DRY CONDITIONS AND SLO WARMUP AS UPPER RIDGE BUILDS
INTO CENTRAL PORTION OF THE COUNTRY WITH QUICK BREAK TO ZONAL FLO. HWVR BY
MID WEEK LTST MRF SHOWS TROF DIGGING AS IT COMES OFF THE COAST WITH FAIRLY
INTENSE SERIES OF S/W MOVING THRU THE SW AND OVR CENTRAL PORTION OF THE
COUNTRY. LWRG HTS SUGGEST SHARPLY IMPROVE CHC FOR SNW LT WEEK AND INTO ERY
NXT WEEK.
GUID TEMPS NOT BAD AND IN LINE WITH SFC TRAJS FCST AS SOURCE RGN IN THE DAKS.
WITH BUILDING RIDGE WARMUP WL BE SLO WITH AT LEAST ONE COLD NGT AHD.
.DSM...NONE
FORSTER
FXUS63 KDMX 050401 AMD ia
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
332 AM EST SUN DEC 5 1999
MAIN PROBLEM WITH THIS FORECAST PACKAGE WILL BE WHEN THE ONSET OF
THE RAIN WILL BE AND WHAT TYPE OF PRECIP WILL END UP BEING.
LATEST WATER VAPOR LOOP SHOWS THE VORT LOBE SPINNING OVER SE KS WITH
A GRADUAL MOVEMENT TO EAST-NORTHEAST. THIS SYSTEM IS PROGGED TO
SHIFT TO THE LOWER OHIO VALLEY BY THIS EVENING AND THEN EAST TO THE
APPALACHIANS BY TOMORROW EVENING. ETA/AVN ARE THE MOST PROGRESSIVE
WITH THIS SYSTEM WHICH LOOKS TO BE THE WAY TO GO AFTER LOOKING BACK
AT THE PREVIOUS RUN.
WE ARE BIT CONCERNED ON WHEN THIS RAIN WILL BEGIN ATTM SINCE THE
PRECIP IS TENDING TO HOLD BACK A COUPLE OF HOURS FROM WHAT THE
ETA/NGM IS PROJECTING DUE TO DRY LOW LEVELS. THE RUC SEEMS TO HAVE A GOOD
HANDLE ON THIS SCENARIO SO WE WILL DELAY THE RAIN UNTIL THE
AFTERNOON TIME FRAME FOR THE LEX AND COLUMBIA GROUPS. COULD ALSO SEE
A FEW RUMBLES OF THUNDER MAINLY ALONG AND JUST AHEAD OF THE SURFACE
BOUNDARY WHICH IS EXPECTED TO PASS THROUGH DURING THE LATE AFTERNOON
AND EVENING. THE ASSOCIATED UPPER LEVEL LOW WITH THIS SYSTEM SHOULD
ALSO PROVIDE FAIRLY DESCENT LAPSE RATES. FWC TEMPERATURES LOOK TO BE
ON TARGET THIS MORNING AFTER A WARM START AND TEMPERATURES COOLING
OFF A LITTLE WHEN THE RAIN BEGINS.
TONIGHT THE MODELS PROJECT THE STEADIER RAINS TO MOVE TO EASTERN KY
BY AROUND MIDNIGHT. HOWEVER...CENTRAL KY AND SOUTHERN INDIANA WILL
BE AWAITING THE PASSAGE OF THE 850 MB FRONTAL BOUNDARY WITH GOOD
700MB FRONTAGENISIS OVER THE AREA. THEREFORE...WE WILL KEEP THE
CHANCES OF RAIN UP OVER MOST OF THE AREA DESPITE A MID LEVEL DRY
SLOT MOVING INTO CENTRAL KENTUCKY. GOOD COLD AIR ADVECTION WILL
BECOME ESTABLISHED OVER THE CWFA AFTER THE FRONT PASSES THROUGH. AS
FOR THE SNOW POTENTIAL...WE ARE NOT CONFIDENT THAT WILL OCCUR SINCE
THE MODEL SOUNDINGS SHOW THE FREEZING LEVEL STAYING ABOVE 1500 FT
AND THIS UPPER LEVEL SYSTEM WEAKENS AS IT HEADS EAST. IT APPEARS
MOST OF THE LIFT EXITS THE REGION BY TOMORROW MORNING WITH CONTINUED
GOOD CAA. ALL THREE MODELS AGREE THAT THERE MAY BE SOME PARTIAL
CLEARING LATE IN THE DAY OVER CENTRAL KY AND SOUTHERN IN WHICH WE
WILL MENTION IN THE ZONES. HOWEVER...THIS WILL NOT HELP TEMPERATURES
MUCH DUE TO CONTINUED STRONG COLD AIR ADVECTION IN PLACE.
.SDF...NONE.
COX
FXUS63 KJKL 050636 ky
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
240 AM CST SUN DEC 5 1999
FRONT CONTINUING TO MAKE ITS WAY ACROSS S LA THIS MORNING WITH A
BROKEN LINE OF SHOWERS FROM KPTN TO KBTR TO W OF KMCB AT 0840Z.
LIGHTNING DATA NOT INDICATING ANY STRIKES WITH THIS ACTIVITY BUT
EXPECT SOME ISOLATED THUNDER LATER AS LEFT FRONT QUADRANT 80 KT
SUBTROPICAL JET MAX NEARS SE LA COAST AROUND DAYBREAK.
TIMING OF RAIN IS GOING TO PLAY A MAJOR ROLE IN AFTERNOON HIGHS. AT
08Z RAIN SHOWERS NEAR KBTR EXTENDING INTO SW MS WITH THE LINE MOVING
E. KLFT AT 06Z SHOWED 71 TEMP AND 66 DEWPOINT WHICH DROPPED TO 58
TEMP AND 55 DEWPOINT ONCE SHOWERS MOVED IN. THIS RAIN HAMPERED THE
WARMUP YESTERDAY ACROSS E PORTIONS OF SE LA WHERE SHOWERS LINGERED
THROUGH THE MORNING. LOOKING AT NEW ORLEANS AREA OBS FROM SATURDAY
THESE LOCATIONS STRUGGLED TO WARM 10-12 DEGREES FROM MORNING LOWS.
WITH THIS IN MIND WILL GO WITH MID 60S W OF A KMCB-KBTR-KHUM LINE
AND AROUND 70 E OF THIS LINE. THIS FOLLOWS CONTINUITY WITH THE
PREVIOUS FORECAST PACKAGE AND WILL MAINTAIN CONTINUITY THROUGH THE
REMAINDER OF THE FORECAST PERIODS AS THE PACKAGE LOOKS ON TRACK.
LATEST TRENDS ON LIX WSR-88D SHOW DBZS INCREASING IN INTENSITY FROM
08 TO 0830Z WHICH IS SEEMING TO PHASE WITH THE NEARING OF THE
SUBTROPICAL JET MAX. LOOKING AT ETA CAPE AND CAP/CIN NUMBERS FOR 12Z
AND 18Z TODAY THE ATMOSPHERE IS UNCAPPED BUT STRONGER CAPES REMAIN
OFFSHORE. A LOOK AT 5/00Z LIX SOUNDING DOES NOT YIELD MUCH WITH RAIN
OCCURRING AT RELEASE TIME. RUC MODEL SURFACE LI FIELD SHOWS NEGATIVE LI
FIELD RESTRICTED TO COAST. SCENARIO LOOKS TO BE STRONGER STORMS
DEVELOPING AROUND DAYBREAK IN WESTERN COASTAL PARISHES OF CWA AND
SPREADING E WITH ENHANCEMENT OF LIFT FROM JET MAX.
WINDS ARE NOT GOING TO BE A FACTOR TODAY AS IN THE PAST TWO DAYS BUT
ARE EXPECTED TO INCREASE AGAIN TONIGHT AS SECONDARY 850 MB TROUGH
SWINGS THROUGH THE AREA. PRELIM NUMBERS FOLLOW.
MCB 64/38/56/32 7000 BTR 63/40/57/33 6000 MSY 69/44/58/40 7100
BIX 69/46/57/38 7100
.NEW...NONE.
LA...NONE.
MS...NONE.
13
FXUS64 KSHV 050817 la
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
328 AM CST SUN DEC 5 1999
WV LOOP AND 88-D RETURNS AS OF 0830 UTC SHW DEFORMATION ZN XTNDG ALG
AND TO W OF I-35 CORRIDOR FM ICT TO MCI. SNOWFALL AMTS IN
NEIGHBORHOOD OF A HALF A FOOT REPORTED IN ICT AREA BUT DECREASED
FTHR TO N IN DEFORMATION ZN. HOWEVER DURING LAST TWO HRS UPRIGHT
CNVTN HAS DEVELOPED BET TOP AND MCI. RUC CONTS TO SHW MOD TO STG H3
DVRGNC ACR NRN END OF AFOREMENTIONED DEFORMATION ZN AS LATEST 90 KT
JET MAX LIFTS NWRD ARND E SIDE OF CLOSED UPR LO. THINK THAT CNVTV
THREAT WILL PERSIST OVR NW CWA UNTIL THRU 1200 UTC THAN END RATHER
QUICKLY AS CONCENTRATION OF H3 DVRGNC DISSIPATES AND POT VORTICITY
GRADIENT MOVE TO N. BASED ON CRNT AND MODEL FCST SPEC HUMIDITY
VALUES AS WELL AS REPORTS UPSTREAM INVOF TOP THINK THAT ISOLD 2-4
INCHES A REASONABLE POSSIBILITY ALG AND W IF I-35 FM MKC TO BETHANY.
UPWRD MOTION APPRS TO HAVE COOLED THE ATM ENOUGH OVR NW CWA THAT
PCPN SHLD HOLD AS SNOW THRU THE AM
BIG QUESTION ATTM IS WHETHER OF NOT TO ISSUE SNOW ADVSY CONSIDERING
CRNT ISOLD NATURE OF CNVTN. WILL EITHER ISUE SNOW ADVSY FOR NARROW
CORRIDOR OF HEAVIEST PCPN AS INDICATED BY 88-D OR ISSUE BROAD ZN FOR
A FEW INCHES AND TREAT ISOLD COUNITIES WITH ADVSY IF NEED DVLPS.
WILL DECIDE AT PRESS TIME.
JUST TO S OF A KC METRO TO MARSHALL TO MACON LN...WV LOOP INDICATES
THAT STRATOSPHERIC AIR HAS ALREADY MOVED IN WITH UPR TROPOSPHERIC
POT VORTICITY MAX. WILL GO WITH LGT RA TDY PSBLY MIXING WITH -SN BUT
NOT MENTION ANY ACCUMULATION. WILL INTRODUCE ENDING TIME FOR LTR
THIS PM IN ALL WRN ZNS.
FOR NE QUAD OF CWA THINKING IS THAT FORCING MECHANISMS WILL WEAKEN
ENOUGH THAT SNOWFALL AMNTS NOT A BIG CONCERN. SINCE STG LIFT IS
NECESSARY TO CHG PCPN TO SNOW AND KEEP IN FRZN STATE WILL POST MIXED
PCPN THRU TDY WITH AN INCH OR LESS ACCUMULATION. WILL INSERT LO POP
FOR -SHSN THIS EVNG IN NE CWA DUE TO MODEL FCST OF DECENT MID/UPR
LVL FROTOGENTIC FORCING OVR ERN IA IN RIGHT ENTR RGN OF JET IN NRN
BRANCH.
FAN/FWC SEEM TO HAVE DECENT HNDL ON TEMPS SO WILL NOT STRAY FAR FM.
ONCE AGN DID NOT HAVE TIME TO CLOSELY EXAMINE XTND FCST THIS AM SO
LEFT UNCHANGED.
.EAX...
KS...NONE.
MO...NONE.
BODNER
»-
FXUS63 KLSX 050928 mo
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSONVILLE FL
955 AM EST SUN DEC 5 1999
SHORT TERM...SATELLITE SHOWED THE STRATO-CU STILL ADVECTING OVER THE
FORECAST AREA (FA) BUT NOT AS EXTENSIVE AS FRIDAY NIGHT. THE
WRINKLE IS THAT RADAR SHOW THAT A FEW COASTAL SHOWERS HAVE POPPED
UP...BUT THIS IS NOT UNEXPECTED. AT 12Z MSAS SHOWED WEAK SURFACE PVA
WITH WEAK TO MODERATE MOISTURE CONVERGENCE JUST OFF THE NORTHEAST
FLORIDA AND SOUTHEAST GEORGIA COASTS. HOWEVER THE RUC AND MESO ETA
SHIFT THE WINDS TO A MORE SOUTHERLY DIRECTION BY LATE AFTERNOON
WHICH SHOULD MOVE THE ACTIVITY ONSHORE NORTH OF OUR CWA...SO
WILL REMOVE THE MENTION OF SHOWERS IN THE ZONES BUT KEEP THEIR
MENTION IN THE COASTAL WATERS. TEMPERATURES SEEMS TO BE A LITTLE
HIGHER THAN FORECAST SO WILL BUMP THE MAX TEMPERATURES A TAD FOR
SOME LOCATIONS TODAY. THE REMAINDER OF THE EARLY MORNING PACKAGE
LOOKS OK.
.JAX...
GA...NONE.
FL...NONE.
BLS
FXUS62 KTBW 051515 fl
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
1010 AM EST SUN DEC 5 1999
EXTENSIVE DECK OF CLOUDS REMAIN TRAPPED BELOW STRONG SUBSIDENCE
INVERSION AT 750 MB. FLOW ABOVE INVERSION GRADUALLY BECOMING
S/SW...WITH BOUNDARY LAYER WINDS SLOWLY VEERING TO MORE SOUTHERLY
COMPONENT. ALTHOUGH BREAKS OF SUNSHINE WILL OCCUR ACROSS CWA THIS
AFTERNOON...SATELLITE TREND FAVORS CONTINUATION OF CONSIDERABLE
CLOUD COVER DESCRIPTOR. CLOUD COVER WILL LIMIT RAPID RISE OF
TEMPS...BUT BELIEVE FORECAST MAXS WILL BE REACHED BY LATE AFTERNOON.
WILL MONITOR TEMPS FOR EARLY AFTERNOON ZONE UPDATE IF RISE DOES NOT
MATERIALIZE. FEW LIGHT SHOWERS/SPRINKLES OCCURRING OVER SE ZONES
HAVE BEEN WEAKENING LAST FEW HOURS...THEREFORE CURRENT POP FORECAST
OK.
MARINE...BROAD RIDGE AXIS HAS REACHED CENTRAL FLORIDA COASTAL
WATERS...RESULTING IN A WEAKENING OF SURFACE WINDS. LATEST RUC
DEPICTS SITUATION WELL...WITH LIGHT WINDS OVER NORTHERN MARINE ZONE
THROUGH AFTERNOON AND E/SE GRADIENT STILL PREVALENT SOUTH OF
SEBASTIAN. WILL DROP WINDS WITH UPDATE...ESPECIALLY N OF COCOA
BEACH. SEAS STILL A LITTLE HIGHER THAN WIND JUSTIFIES DUE TO SMALL
SWELL COMPONENT.
.MLB...NONE.
WIMMER/SPRATT
FXUS62 KEYW 051458 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
945 AM EST SUN DEC 5 1999
COLD FRONT (ALONG EAST LA - EAST MS) MOVING EAST AT 15 KT AND IS ON
PACE TO REACH THE WESTERN PORTION OF OUR CWA BY THIS EVENING...IN
GOOD AGREEMENT WITH ETA/AVN. (NGM LOOKS A LITTLE SLOW). LATEST RUC
DID A GOOD JOB AT FORECASTING THE LIGHT RAIN TO OUR WEST. 'TIS
ASSOCIATED WITH MOISTURE FLUX CONVERGENCE AND WEAK ISENTROPIC LIFT
ALONG THE WARM FRONT. THE RUC FORECASTS THIS RAIN TO REMAIN LIGHT
AND NOT MAKE MUCH EASTWARD PROGRESS. THEREFORE...CURRENT ZONES LOOK
GOOD AND WILL ONLY MAKE COSMETIC CHANGES.
CWF: WINDS ARE STILL HOWLING AROUND 20 KT AT THE BUOYS...WITH SEAS
UP TO 7 FEET. HOWEVER...WINDS SHOULD DECREASE A LITTLE THIS
AFTERNOON WITH A WEAKENING PRESSURE GRADIENT. THIS IS FORECASTED BY
THE ETA (WHICH HAS HAD THE BEST WIND FORECAST SO FAR)...AND IS ALSO
SUPPORTED BY BUOY DATA TO THE WEST. WILL KEEP CURRENT ADVISORY
CRITERIA AS IS.
.TLH...SCA TODAY APALACHICOLA TO DESTIN.
FOURNIER
FXUS62 KMFL 051439 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1105 AM EST SUN DEC 5 1999
LK EFFECT CLOUDS AND WIND ARE MAIN UPDATE CONCERNS
15Z SFC ANALYSIS SHOWS 1006 MB LOW JUST NORTHEAST OF GEORGIAN BAY
WITH COLD FRNT DRAPED BACK INTO ERN TX. IR SAT...RADAR MOSAIC...AND
SFC OBS ALL POINT TO RAINY SUNDAY ALG AND AHEAD OF SFC FRONT...WITH
-SN OBSERVED BEHIND FRNT IN IA...WRN MO...AND ERN KS. UPR MI IS
BETWEEN THE LOW PRESSURE AREA AND A 1025 MB SFC HIGH NEAR KFAR AND
AS A RESULT OF FAIRLY TIGHT PRESSURE GRADIENT IS EXPERIENCING SOME
GUSTY WINDS THIS MORNING. GUSTIEST WINDS ARE FOUND ALONG LK SUPERIOR
WHERE P59...CMX...AND ANJ HAVE REPORTED WINDS AOA 20 KT.
PER RUC AND MESOETA SFC TO BLYR WINDSPEEDS AND SFC ANALYSIS...EXPECT
GUSTY WINDS IN THE 10 TO 20 KT RANGE TO CONTINUE THROUGH MAJORITY OF
AFTERNOON BEFORE SLACKENING. IN ADDITION TO NW WINDS...THERMAL TROF
AT H8 AS DEPICTED BY ETA...NGM...AND AVN (ALTHOUGH ETA SHOWS A COLD
BIAS BY 2-4 DEG C PER MORNING SOUNDINGS AT INL AND GRB) THROUGH THE
DAY AND STEADY TEMPERATURES PER FLP GUIDANCE FOR ENTIRE U.P...WILL
KEEP TEMPS STEADY AROUND CURRENT READINGS.
DESPITE LATEST IR SAT SHOWING CLOUDS OVR NRN LK SUPERIOR BREAKING UP
A BIT...WILL CONTINUE TO GO WITH MOSTLY CLOUDY FOR ALL ZONES.
THINKING IS THAT H8 TEMPS NEAR MINUS 10 DEG C (PRODUCING DLT T/S
AROUND 14-15 ACROSS THE LK) WILL HELP TO SUSTAIN LK CLOUDS FOUND OVR
ENTIRE UPR MI ATTM. ALSO DUE TO THE INSTABILITY...FLURRIES AND LGT
SN SHOWERS POSSIBILITY WILL CONTINUE FOR THE REMAINDER OF AFTN. 88D
SHOWING LGT RETURNS ATTM AND THAT SHOULD STAY THE CASE SINCE
INVERSION HTS WILL REMAIN AROUND 3K FT THROUGHOUT DAY OVR NRN FA PER
RUC FCST SOUNDINGS.
.MQT...NONE.
JLA
FXUS63 KGRR 051603 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1029 AM EST SUN DEC 5 1999
SKC OVR CAE CWA ATTM. CLDS ALG THE CST AND INTO SE GA...WITH WDLY
SCT SHRA NR CST. 12Z CHS SOUNDING INDICATES MOISTURE 900-750 MB WITH
WIND DIR SW AT THAT LEVEL. SATL TRENDS INDICATE NE MVMT OF
CLDS...WITH APPEARANCE THAT CSRA WILL SEE LESS CLDNS THIS AFTN THAN
REMAINDER CWA. LTST RUC SUPPORTS MOISTURE STREAMING NE...AND
CONFINES PCPN TO NR THE CST. SO...WILL WORD LESS CLDS CSRA...AND
REMOVE POP FOR THEM. WILL ALSO RAISE MAX TEMPS CSRA DUE TO MORE SUN.
.CAE...NONE.
MILLER
FXUS62 KCHS 051502 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1045 AM EST SUN DEC 5 1999
WAVE OF LOW PRESS TO MOVE NE ALONG FRONT ACRS ONT AND INTO QUE TDY.
FRONT TO MOVE SLOWLY EAST ACRS THE EASTERN GREAT LKS TDY DUE TO UPR
LVL FLOW BEING NEARLY PARALLEL TO IT. THIS FRONT FORECAST TO START TO
DROP DOWN ACRS THE FA OVRNITE TONITE.
12Z RUC INDICATES SOUTHERLY FLOW TO INCREASE TDY WITH HIGHS IN THE
M40S-M50S. NO FRONTAL PCPN INDICATED THRU 00Z THOUGH. 11Z LAMP DATA
SHOWS FIRST MEASURABLE PCPN INTO THE ST LAW VLY BETWEEN 00Z AND 06Z
TONITE. START TIME FOR PCPN APPEARS TO BE AROUND 00Z IN ST LAW
VLY...AROUND 06Z CHAMP VLY...IN BETWEEN IN THE ADIRONDACKS...AND
AFTER 06Z ELSEWHERE. MODELS INDICATE THAT UPR LVL DYNAMIX WILL NOT
COME INTO PLAY ACRS THE FA UNTIL AFT 06Z TONITE.
ATTM...SCT LT PCPN INDICATED ON AREA 88DS MOVING NE ACRS FA IN H85
WAA/POSITIVE MOISTURE ADVECTION PATTERN. THESE SHRA TO DEPART THE
ENTIRE FA AFT 18Z TDY. PESKY FOG STUBBORN TO SCOUR OUT AND MAY LEAVE
IN MTN ZONES AND SOUTHERN VT FOR A TIME THIS AFT.
SAT PIX INDICATE BREAKS IN CLD COVER MOSTLY FILLING IN...BUT FEEL
BEST CHC FOR ANY PERIODS OF SUN LATER THIS AFT WILL BE IN SOUTHERN
VT.
HAVE INDICATED ABOVE TRENDS IN LATE MORNING UPDATE OF THE WORK ZONES.
WILL HOLD REAL ZONES UNTIL AFTER 11 AM SO THAT SHRA CAN CLEAR AS MUCH
OF THE FA AS POSSIBLE.
.BTV...NONE.
MURRAY
FXUS61 KBTV 051409 vt
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
234 PM CST SUN DEC 5 1999
12Z CHARTS SHOWED NEARLY VERTICALLY STACKED UPPER LOW CONTINUING TO
PROGRESS NE THROUGH SE MO. WV VERIFIES THIS WELL WITH NICE
CLOSED VORT MAX NEARING ST LOUIS AS OF 19Z. NRN STREAM SHORTWAVE
CONTINUES TO MOVE ACROSS SRN ONTARIO. SURFACE LOW ASSOCIATED WITH
THIS SRN SYSTEM CONTINUES TO MOVE NE AND AT 18Z WAS LOCATED TO
THE EAST OF KCMI NEAR THE IN BORDER. NICE DEFORMATION ZONE ON NORTH
SIDE OF THIS SYSTEM BEING AIDED BY COUPLING OF RR QUAD OF NRN STREAM
JET OVER NE IA INTO WI AND LF QUAD OF SRN STREAM JET OVER MID
MISSISSIPPI VALLEY. ALL OF THIS IS HELPING TO GIVE ACCUMULATING
SNOWS ACROSS SOUTHEASTERN 1/2 OF CWA...WHILE THE REST OF THE CWA WAS
SPARRED THE BRUNT OF THIS SYSTEM AS DRY AIR HAS FILTERED INTO FROM
THE NW. A FEW LOCATIONS IN CENTRAL CWA HAVE SEEN UP TO 2-4 INCHES OF
SNOW ACCUMULATION...MAINLY IN THE QUAD CITIES AREA. TIGHT PRES
GRADIENT HELPING TO PRODUCE BREEZY CONDITIONS AS WELL TODAY.
SURFACE RIDGE AXIS CURRENTLY EXTENDS ACROSS THE HIGH PLAINS OF ERN
DAKOTAS DOWN THROUGH WRN KS. TEMPS THIS MORNING WERE QUITE COLD NEAR
SURFACE RIDGE AXIS WITH MANY LOCATIONS IN THE SINGLE DIGITS AND
TEENS. DOWN STREAM...UPPER LEVEL RIDGE BUILDING INTO THE
PLAINS REGION...AS NEXT WEAKER SHORTWAVE MOVES THROUGH THE
INTERMOUNTAIN REGION. NEXT LARGER MORE POWERFUL SYSTEM EVIDENT
BEHIND THIS MOVING TOWARD THE PAC NW COAST...WITH STRONG 150KT JET
AIMED TO HELP DIG SYSTEM INTO THE WEST COAST.
FORECAST CHALLENGES INCLUDE TIMING END OF SNOW THIS EVENING...CLOUD
TRENDS TONIGHT...AND TEMPS TONIGHT THROUGH MONDAY. ALSO TIMING OF
NEXT SYSTEM FOR LATE THIS WEEK.
12Z MODELS SEEMED TO INITIALIZED FAIRLY WELL ON CLOSED LOW OVER MO...
BUT THE RUC SEEMED TO HAVE THE LOCATION AND STRENGTH DOWN THE BEST.
ETA SEEMED TO HAVE THE BEST HANDLE ON THE UPPER LEVEL RIDGING
BEHIND THIS SYSTEM. AVN SEEMED TO INITIALIZE BEST WITH 850 MB THERMAL
FIELDS TO THE NW AND THIS IS REFLECTED WITH FAN SUPERIOR PERFORMANCE
WITH LOWS THIS MORNING. AT THE SURFACE...NGM INITIALIZED AND
CONTINUES TO DO WELL AT 18Z WITH THE PLACEMENT OF THE SURFACE LOW
NEAR THE IL/IN BORDER...AS WELL AS THE RIDGE AXIS TO OUR WEST AND
CONSEQUENT PRESSURE GRADIENT BETWEEN THE TWO. ONLY MODEL TO PICK ON
SNOW AMOUNT ACROSS CENTRAL CWA THIS AFTERNOON WAS THE ETA WITH THE
RUC DOING GOOD WITH THE TIMING AND EXTENT OF THE PRECIP...WITH OTHER
MODELS UNDERDOING PRECIP AMOUNTS COMPLETELY. MODELS NOT DOING WELL IN
LOW CLOUD DECK ASSOCIATED WITH LLVL COLD POCKET CURRENTLY MOVING
SOUTH ACROSS NE IOWA WRN WI BEHIND DEPARTING SYSTEM. WITH THE NGM
VERIFYING THE CLOSEST. WILL SIDE WITH RUC IN TIMING OF END OF PRECIP
THIS EVENING...AND WITH A BLEND OF NGM/AVN FOR CLOUD COVER. WITH FAN
TEMPS LOOKING THE BEST TONIGHT.
TONIGHT...
BIG QUESTION IN SHORT TERM IS TIMING OF PRECIP TO END ACROSS ERN CWA.
VORT MAX SHOULD CONTINUE TO LIFT NE ACROSS CENTRAL IL INTO THE
EVENING HOURS...GIVING GOOD EASTWARD PROGRESSION OF SNOW BAND THROUGH
THE ERN ZONES. LATEST RADAR TRENDS INDICATE THAT SOUTHERN END OF BAND
IS MAINLY -SN AND IS MOVING QUICKLY TO THE EAST. IR SAT TRENDS SHOW
GOOD WARMING OF CLOUD TEMPS INDICATING WEAKENING OF DYANAMIC LIFT AS
WELL. THIS SHOULD GIVE MOST LOCATIONS IN ERN ZONES WITH LIGHT SNOW
ENDING FROM THE WEST...WHILE FAR NE COUNTIES WILL SEE MOD SNOW WITH
ACCUMULATIONS OF ANOTHER INCH BEFORE ENDING FROM THE WEST BY 00Z.
WILL WORD ZONES IN THE EAST TO REFLECT THIS DIMINISHING TREND WITH AN
EVENING WORDING. WILL WAIT UNTIL LAST MINUTE TO ISSUE WORDING FOR
THESE ZONES BASED ON RADAR TRENDS/SPOTTER REPORTS. NEXT QUESTION
TONIGHT IS LOW TEMPS. VERY LARGE RANGE OF SNOWCOVER COULD HAVE
PRONOUNCED EFFECT ON LOW TEMPS. MOST AREAS IN THE NW DIDN'T SEE ANY
SNOW AT ALL. HOWEVER...THIS AREA WILL SEE THE CALMEST WINDS. WHILE
AREAS IN THE CENTRAL AND SE ZONES WILL SEE GRADIENT WINDS RELAXING
LATE TONIGHT. MODELS DIVERGE ON LOW CLOUD COVER AS WELL...WITH THE
ETA THE MOST BULLISH IN KEEPING 80%+ RH IN TO CENTRAL/ERN ZONES
THROUGH 12Z. IR/VIS SAT INDICATES THAT CLOUDS ARE LIKELY ASSOCIATED
WITH 850MB COLD POOL. ALL MODELS INDICATE THAT THIS COLD POOL SHOULD
SHIFT EAST OF CWA DURING THE NIGHT. WILL GO WITH PARTLY CLOUDY SKIES
IN THE WEST EARLY BECOMING MOSTLY CLEAR LATE. FOR THE EASTERN ZONES
MID LEVEL CLOUDS SHOULD DISSIPATE BY LATE EVENING AT THE LATEST...SO
WILL GO WITH BECOMING MOSTLY CLEAR OVERNIGHT. MOS OUTPUTS AGREE IN
DECOUPLING WINDS. NGMMOS OVERDID TEMPS LAST NIGHT NEAR RIDGE AXIS
AROUND 3 DEGREES...SO WILL UNDERCUT IN MOST ZONES...AND FOLLOW CLOSER
TO FAN NUMBERS. MAY SEE EVEN COLDER TEMPS IN AREAS THAT HAVE THICK
SNOW COVER.
MONDAY...
SKIES SHOULD BE CLEAR WITH WINDS BECOMING SOUTHWEST AS SURFACE HIGH
SHIFT TO THE SE OF CWA. TEMPS WILL CONTRAST BETWEEN AREAS THAT
HAD SNOW COVER AND THOSE THAT DIDN'T. 850 TEMPS WARM TO BETWEEN 2
AND 3C BY LATE IN THE DAY ACROSS WESTERN ZONES. WILL LIKELY SEE
TEMPS APPROACHING FWC NUMBERS IF NOT A LITTLE WARMER OUT WEST. WILL
UNDERCUT FWC/FAN NUMBERS IN AREAS WITH SNOWCOVER..AS TEMPS SHOULD
BE HELD TO THE LOWER 30S.
MONDAY NIGHT AND TUESDAY...
MID/HIGH LEVEL CLOUDS ASSOCIATED WITH WEAK SHORTWAVE MOVING OUT OF
ROCKIES INTO THE PLAINS SHOULD GIVEN PARTLY CLOUDY SKIES. TEMPS
MONDAY NIGHT SHOULD BE COLDER AGAIN IN AREAS THAT STILL HAVE
REMAINING SNOW COVER AND IN ERN ZONES WHERE WINDS WILL DECOUPLE THE
BEST...WITH WRN ZONES SEEING WARMER CONDS AS WINDS WILL STAY UP AT 5
KTS OR MORE HELPING TO PREVENT GOOD RAD COOLING ALONG WITH THING.
CLOUDS SHOULD CLEAR EARLY TUESDAY AS UPPER LEVEL FORCING WEAKENS.
NEXT MAJOR TROUGH POISED TO DIG INTO THE WEST COAST. AT THE
SURFACE WINDS SHOULD SWITCH TO THE SOUTH ON TUESDAY AHEAD OF NEXT
WEAK SURFACE TROUGH THAT SLOWLY MOVES EAST ACROSS THE PLAINS.
SOUTHERLY WINDS SHOULD BRING WITH IT GOOD WARMUP FOR MOST LOCATIONS
DURING THE DAY SO WILL FAVOR WARMER FAN NUMBERS.
EXTENDED...
DPROG/DT INDICATES THAT LATEST AVN RUN IN AGREEMENT WITH YESTERDAY'S
BELIEF THAT NEXT TROUGH SHOULD DIG MORE INTO THE SW U.S. 12Z AVN
ALSO SHOWS SYSTEM TO BE DEEPER THAN 00Z MRF. GIVEN GOOD TRACK RECORD
OF AVN THIS FALL HAVE NO QUALM IN BELIEVING A CONTINUED
INTENSIFICATION AND DEEPENING OF THIS NEXT SYSTEM. WITH A DEEPER
TROUGH DEVELOPING IN THE WEST...WE SHOULD SEE SLIGHTLY WARMER
CONDITIONS ON WED THAN TUE AS WAA CONTINUES DESPITE THE INCREASE
IN MID AND HIGH CLOUD COVER...WHICH MATCHES WELL WITH GOING
FORECAST. NEXT QUESTION BECOMES TIMING AND DURATIONS OF PRECIP FOR
NEXT SYSTEM. LATEST EURO/UKMET IN REMARKABLE AGREEMENT AND IN LINE
WITH LATEST AVN IN TROUGH DIGGING INTO 4 CORNERS REGION BY EARLY WED.
THIS SLOWER DEEPER SOLUTION WOULD ARGUE FOR HOLDING OFF PRECIP UNTIL
THURS ACROSS CWA...AS BEST LIFT REMAINS ACROSS SRN PLAINS. COLD
FRONTAL BOUNDARY SHOULD ALSO REMAIN TO THE WEST ACROSS IA/NE BORDER
UNTIL MAIN ENERGY EJECTS OUT OF PLAINS ON THURSDAY...AND SHORTWAVE
PHASES WITH NRN STREAM WAVE. THIS SYSTEM LOOK REMARKABLY SIMILAR TO
LAST ONE...AND WOULDN'T BE SURPRISED TO SEE VERY SIMILAR TRACK OF
UPPER LOW AND SURFACE LOW AS MRF INDICATING. THEREFORE WILL GO WITH
CHANCE OF RAIN ON THURS...WHICH SHOULD MIX WITH AND CHANGE TO ALL
SNOW FRI BEFORE ENDING LATE FRI. BUT SYSTEM SHOULD MOVE QUICKLY AS
NEXT MAJOR STORM MOVING INTO SW U.S. WILL HELP EJECT IT. ACTIVE
PATTERN LOOKS TO CONTINUE WELL INTO NEXT WEEK.
...PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE
ARE CONTAINED WITHIN QUAD CITIES ZONE FORECAST.
DBQ BU 018/034 021/044 029 77000
CID BU 015/036 022/045 031 77000
MLI BU 015/033 021/043 030 77000
BRL BU 019/034 023/045 032 77000
.DVN...
IA...NONE.
IL...NONE.
MO...NONE.
CROSBIE
FXUS63 KILX 052025 il
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE COLUMBIA SC
1242 PM EST SUN DEC 5 1999
.UPDATE...
MST CLD CVR MOVG NE AWAY FROM CENT CWA. SOME DIURNAL CU FORMING
THOUGH. ALSO...TEMPS ALREADY REACHING FCST MAXES W AND CENT CWA. AGS
MAY REACH RECORD MAX OF 77. WINDS PICKING UP A BIT.
.PREV DISC...
SKC OVR CAE CWA ATTM. CLDS ALG THE CST AND INTO SE GA...WITH WDLY
SCT SHRA NR CST. 12Z CHS SOUNDING INDICATES MOISTURE 900-750 MB WITH
WIND DIR SW AT THAT LEVEL. SATL TRENDS INDICATE NE MVMT OF
CLDS...WITH APPEARANCE THAT CSRA WILL SEE LESS CLDNS THIS AFTN THAN
REMAINDER CWA. LTST RUC SUPPORTS MOISTURE STREAMING NE...AND
CONFINES PCPN TO NR THE CST. SO...WILL WORD LESS CLDS CSRA...AND
REMOVE POP FOR THEM. WILL ALSO RAISE MAX TEMPS CSRA DUE TO MORE SUN.
.CAE...NONE.
MILLER
FXUS62 KCAE 051531 sc