SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
925 PM MST SUN DEC 12 1999
SYNOPSIS...WEAK HIGH PRESSURE BUILDING INTO THE DESERT SOUTHWEST
WILL BRING CLEAR SKIES AND A WARMING TREND THROUGH MONDAY. A TROUGH
WILL PASS NORTH OF THE AREA TUESDAY AND WEDNESDAY...BRINGING
SLIGHTLY COOLER TEMPERATURES TO THE REGION. DRY AND SEASONABLE
CONDITIONS WILL BE IN STORE THROUGH FRIDAY.
DISCUSSION...NO MAJOR CHANGES NEEDED TO CURRENT FORECAST. TEMPS ARE
SOMEWHAT RELUCTANT TO FALL THIS EVENING. HOWEVER...SEE NO REASON
THAT WITH CLEAR SKIES...LIGHT WINDS AND DEW POINTS IN THE LOW TEENS
THAT WE WON'T REACH LOWER 30S HERE IN TUCSON METRO AREA. A WEAK
UPPER TROF WILL MOVE ACROSS FAR NORTHERN AZ LATE TONIGHT INTO
MONDAY. THE 18Z MESOETA AND 00Z RUC/ETA ALL SUGGEST THAT THE CI WILL
BEGIN TO MOVE INTO OUR WESTERN CWA AROUND 12Z THIS MORNING. THIS
CORRELATES WELL WITH CURRENT IR SAT IMAGERY WITH THE CI BAND
EXTENDING FROM LAX TO CENTRAL UT. ALTHOUGH IT WOULD BE A MINOR
CHANGE TO CURRENT PACKAGE...MID-SHIFT MAY WANT TO ADD OCCASIONAL
HIGH CLOUDS TO THE MONDAY PERIOD. EXPECT CI WILL BE THIN ACROSS
SOUTHERN AZ...HAVING LITTLE EFFECT ON OVERALL HIGH TEMPS. RASMUSSEN
.TWC...NONE.
FXUS65 KFGZ 130414 az
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
905 PM MST SUN DEC 12 1999
SYNOPSIS...A COLD FRONT WILL BRUSH NORTHERN ARIZONA MONDAY AND
BRING INCREASING CLOUDS AND WIND TO MOST OF THE AREA AND A CHANCE
OF SNOW GENERALLY NORTH OF THE GRAND CANYON. COLD AIR BEHIND THIS
FRONT WILL BRING COOLER DAYTIME TEMPERATURES TUESDAY. HIGH PRESSURE
WILL REBOUND WEDNESDAY THROUGH FRIDAY FOR CLEAR SKIES AND WARMING
DAYTIME TEMPERATURES.
DISCUSSION...VORT FEATURE NEAR 45N/130W ATTM INITIALIZED ON 13/00Z
MODELS. RUC AND ETA/MSO BEST RESOLVE THE STRUCTURAL DETAILS ALONG
THE OR/CA COAST. GENERAL TREND IS TO MOVE H5 SHORTWAVE TROUGH
RAPIDLY SE ACROSS NRN CA/NV AND ACROSS NRN AZ 13/18Z THROUGH
14/00Z. HGT TENDENCY ANALYSIS SUPPORTS THIS RAPID MOVEMENT. PREFER
THE DEEPER ETA SOLN BASED ON JET STREAK ANALYZED UPSTREAM OF TROUGH
AXIS BETWEEN 47N/140W AND 40N/132W. TROUGH, ALTHOUGH PROGRESSIVE,
HAS INCREASED IN AMPLITUDE LAST 3 HRS. GOOD LOW LEVEL MOISTURE IN
THE BAROCLINIC ZONE OF THE TROUGH AND EXPECT MORE CLOUDS FOR
NORTHERN AZ. WILL BUMP UP POPS IN NORTHERN ZONES WITH EVENING ZFP
(2ND PERIOD) UPDATE. NO OTHER CHANGES. MEC
.FGZ...NONE.
.FGZ...NONE.
FXUS65 KPSR 130404 az
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
207 PM EST SUN DEC 12 1999
CURRENTLY: LOW PRESSURE CENTER (AND ASSOCIATED COLD FRONT) LOCATED
ALONG THE TX-LA BORDER...MOVING EAST AT 20 KT. ALL THREE 12 UTC
MODEL RUNS INITIALIZED THIS FEATURE WELL. THE 500 MB LOW OVER THE TX
BIG BEND HAS REACHED ITS LOWEST LATITUDE AND IS TURNING THE
PROVERBIAL CORNER. THE DEVELOPING SQUALL LINE (ALONG THE APPROACHING
FRONT) IS VERY THIN AND DOES NOT EXTEND VERY FAR INTO THE GULF YET.
SOME RAIN IS OCCURRING ACROSS THE WEST PANHANDLE COASTAL
WATERS...CAUSED BY WEAK ISENTROPIC LIFT ALONG THE 305K THETA SURFACE
(ACCORDING TO THE RUC).
MODELS/ZONES: THE MODELS ARE IN GOOD AGREEMENT WITH JUST ABOUT
EVERYTHING THIS FORECAST PERIOD. WITH STRONG Q-G FORCING AND
ABUNDANT MOISTURE...IT'S NOT REALLY A QUESTION OF IF BUT WHEN IT
WILL RAIN. WITH ISENTROPIC LIFT AND SHOWERS ALREADY OCCURRING JUST
TO THE WEST...WILL HAVE TO INCLUDE SOME POPS OVERNIGHT FOR WESTERN
SECTIONS. THE MAIN LINE SHOULD ARRIVE BY LATE MORNING IN WESTERN
SECTIONS...AND AFTERNOON ELSEWHERE. THE RAIN SHOULD EXIT COMPLETELY
ON TUESDAY MORNING. SPC HAS OUTLOOKED OUR COUNTY WARNING AREA IN A
SLIGHT RISK FOR MONDAY. THIS MAKES SENSE GIVEN THE DECENT DYNAMICS.
HOWEVER...THE ETA FORECAST VERTICAL WIND SHEER IS NOT OVERLY
IMPRESSIVE (STRAIGHT LINE...DU/DZ=30KT/6KM). INSTABILITY MAY BE A
PROBLEM TOO IF A LARGE AREA OF FOG/STRATUS DEVELOPS OVERNIGHT. WILL
LEAVE OUT STRONG STORM WORDING FOR NOW...AND LET THE MID SHIFT GET A
FEEL FOR HOW THE SQUALL LINE DEVELOPS.
AS MENTIONED...FOG/STRATUS DEVELOPMENT IS A FORECAST PROBLEM.
STRATOCU DECK APPEARS TO BE ERODING ACROSS THE CWA. IF THIS
OCCURS...LIGHT...MOIST SOUTHERLY WINDS AND RADIATIONAL COOLING WILL
PERMIT LOTS OF FOG/STRATUS TO DEVELOP (AS WAS THE CASE THIS
MORNING). FWC IS GOING FOR IT...AND SO WILL I. TEMPS WILL BE TRICKY
BECAUSE OF CLOUDS/FOG/RAIN FORECAST. THERE IS QUITE THE DISCREPANCY
BETWEEN FAN AND FWC ON MONDAY. TEMPS ACROSS THE CENTRAL GULF COAST
ARE WARM RIGHT NOW...AND I WILL FOLLOW FWC CLOSELY ON THIS ONE.
CWF: WINDS ARE PICKING UP OVER THE GULF WITH THE INCREASING PRESSURE
GRADIENT. WILL GO SCEC BASED ON CURRENT BUOY OBS AND MODEL OUTPUT.
EXTENDED: 00 UTC UKMET AND MRF ARE IN CLOSE ENOUGH AGREEMENT THAT I
FEEL COMFORTABLE ABOUT FOLLOWING MRF MOS.
PRELIM NUMBERS:
TLH 58 75 51 62 37 285
PFN 63 70 52 63 43 384
DHN 60 72 47 60 40 384
ABY 57 73 49 60 36 385
VLD 57 77 53 66 40 -86
.TLH...SCEC ALL SEGMENTS.
FOURNIER
FXUS62 KMFL 121902 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
955 PM EST SUN DEC 12 1999
MAINLY COSMETIC CHANGES FOR TONIGHT TO DROP MENTION OF "AFTER
MIDNIGHT" FOR THE POPS IN THE NORTH AND JUST GO LIKELY. SHOWERS OVER
AL SHOULD REACH NW GA DURING THE NIGHT. RUC MODEL SHOWS LI GOING
NEGATIVE NORTHWEST CORNER BY 12Z SO WILL ADD MENTION OF THUNDER FOR
THAT AREA TOWARD DAYBREAK. SOME MINOR WIND AND TEMPERATURE
ADJUSTMENTS BUT DOUBT THERE IS MUCH OF A SEVERE THREAT FOR TOMORROW.
LATEST SURFACE BASED LI'S SHOW AREA OF STABLE AIR BUILDING ACROSS
NORTH GEORGIA FROM THE CAROLINAS IN A HYBRID WEDGE TYPE OF
SITUATION. MIDNIGHT SHIFT CAN RE-EVALUATE SITUATION AND BEEF UP THE
WORDING IF NEEDED.
.ATL...NONE
JRN
FXUS62 KFFC 121903 ga
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
840 PM EST SUN DEC 12 1999
01Z SURFACE ANALYSIS SHOWING HIGH PRESSURE RIDGE MOVING OFF SHORE. BL
FLOW STARTING TO TURN TO THE SOUTH AS HIGH MOVES AWAY AND LOW OVER THE
GULF STARTS TO MOVE TOWARD THE TENNESSEE VALLEY. RATHER LARGE AREA OF
RAIN MOVING UP FROM THE LOWER MISSISSIPPI VALLEY INTO THE OHIO
VALLEY.. BUT ONLY SCATTERED LIGHT RETURNS SHOWING UP ON NEIGHBORING
RADARS TO THE WEST. IR LOOP SHOWING MAINLY CLEAR SKIES ACROSS AREA AT
TIME.. WITH THE MOISTURE HOLDING TO THE SOUTH AND WEST.
18Z ETA AND 00Z RUC INDICATING MAINLY HIGH LEVEL MOISTURE FOR A GOOD
PORTION OF THE NIGHT OVER THE MID ATLANTIC. TOWARD DAYBREAK IN THE
WEST.. LOW LEVEL MOISTURE INCREASES AS SYSTEM OVER THE GULF COAST
INCHES CLOSER TO THE AREA. CURRENT FORECAST HAS A GOOD HANDLE ON
INCREASING LOW CLOUDS TOWARD DAYBREAK IN THE WEST... ALONG WITH A SMALL
POP FOR THE HIGHLANDS IN CASE SOME LIGHT RAIN SPILLS OVER THE
MOUNTAINS. HIGH CLOUDS HAVE CLEARED A LITTLE MORE THAN EXPECTED THIS
EVENING.. AND EVENING UPDATE WILL INCLUDE SOME MINOR ADJUSTMENTS TO
CLOUD FORECAST TO ACCOUNT FOR THIS.
RELATIVELY DRY AMS IN PLACE AT THE SURFACE.. WITH DEW POINTS IN THE
LOW/MID 20S MOST AREAS. ALL MODELS CONSISTENT IN INCREASING LOW LEVEL
MOISTURE OVERNIGHT.. WITH DEW POINTS IN THE WEST SHOWING AN INCREASE
WELL INTO THE 30S TOWARD DAYBREAK. AGREE WITH CURRENT FORECAST TEMPS IN
THE WEST.. WITH A LOW TEMP OCCURRING DURING THE NEXT 4-5 HOURS AND
TEMPS RISING CLOSE TO DAYBREAK. LAMP GUIDANCE HAS BEEN CONSISTENT WITH
THE 3-HOURLY FWC TEMPS ELSEWHERE.. BOTH OF WHICH ARE VERIFYING PRETTY
WELL. LAMP TEMPS OVERNIGHT ARE CLOSE TO CURRENT FORECAST LOWS... SO
ONLY A COUPLE OF MINOR ADJUSTMENTS PLANNED FOR TEMPS.
WILL HAVE TO WATCH LOW TEMPS TONIGHT IN THE SHENANDOAH VLY. PRECIP
POTENTIAL INCREASES AFTER 12Z.. AND IF TEMPS GET TOO LOW WE MIGHT SEE A
BRIEF PERIOD OF SOME MIXED PRECIP BEFORE WARM AIR MAKES IT DOWN TO THE
SURFACE AND CHANGES EVERYTHING TO RAIN. MODEL SOUNDINGS FROM 18Z ETA
SUGGEST THAT WARM AIR WILL MAKE ITS WAY INTO THE AREA AN HOUR OR TWO
AHEAD OF THE PRECIP... BUT THIS BEARS WATCHING OVERNIGHT.
.LWX...NONE.
MARGRAF!
FXUS61 KLWX 122043 md
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1055 PM EST SUN DEC 12 1999
LATEST IR LOOPS SHOW LOW LOW CLOUDS DEVELOPING ACROSS LAKE MI AND NW
LOWER IN AREAS WHERE MID/HI CLOUDS HAVE DEPARTED. LIGHT FOG ALSO
COVERS MUCH OF THE FCST AREA. 00Z ETA FCST SOUNDINGS SHOW LOW LEVEL
INVERSION DEVELOPING MUCH MORE THAN THE RUC FCSTD WHICH MAY EXPLAIN
THE ST DEVELOPMENT. NOT A LOT OF MOISTURE TO WORK WITH WITH ONLY THE
LOWEST 50 MB BEING CLOSE TO SATURATION. THUS THERE COULD BE A FEW
BREAKS IN THE OVC AT TIMES BUT WILL QUICKLY FILL IN WITH EITHER MORE
CLOUDS OR FOG. WILL UPDATE THE FCST TO MENTION AREAS OF FOG AND NEAR
STEADY TEMPS.
.GRR...NONE.
FXUS63 KMQT 130346 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
409 PM EST SUN DEC 12 1999
PROBLEMS IN NEAR TERM DEAL WITH CLDS AND TEMPS. BY MIDWEEK...
CONCERN WILL PCPN CHCS AND TYPE WITH DEVELOPING CYCLOGENESIS OVER
THE UPPER MIDWEST...AND THEN LES POTENTIAL FOR LATE WEEK WITH CAA
BEHIND DEEPENING LOW FCST TO TRACK N TO HUDSON BAY OVER THE
WEEKEND.
WV LOOP AND RUC UPR ANALYSIS INDICATE PROGRESSIVE NRN STREAM PATTERN
WITH BROAD MEAN TROF OVR WRN GRT LAKES AND THEN RAPIDLY BUILDING RDG
OVR WRN CONUS. NEAR INFLECTION POINT OF THESE FEATURES...SHRTWV MOVG
INTO WRN MN WITH GOOD DRYING AND SUBSIDENCE BEHIND IT NOTED ON WV
LOOP. MODELS CONSISTENT IN MOVG SHRTWV AND SUBSEQUENT
DRYING/SUBSIDENCE ACROSS FA OVRNGT AND THEN BUILDING UPR RDG INTO
REGION ON MONDAY. PROBLEM THIS EVNG WL BE LOW CLDS AND PATCHY FOG
WHICH PERSISTS OVR CNTRL AND ERN ZONES. 12Z GRB SNDG REVEALS MSTR
TRAPPED UNDER SUBSIDENCE INVERSION AT 950 MB. WITH LGT SW WINDS AHD
OF SFC TROF OVR MN...LOOK FOR UPSLOPE CLDS AND PATCHY FOG TO LINGER
OVR CNTRL ZONES THIS EVNG THEN SCOUR OUT LATER TONIGHT BEHIND WL
SUBSIDENCE BEHIND SHRTWV. DRY LYR FM 950-725 MB NOTED GRB SNDG
SHOULD PROHIBIT ANY PCPN AHD OF SHRTWV TONIGHT. ALSO UPSTREAM OBS
AND 88D LOOP NOT INDICATING ANY PCPN ATTM.
WITH UPR RDG AND ATTENDANT DRYING OVR FA MON INTO MON NIGHT...LOOK
FOR MOSTLY CLR SKIES. RDG AXIS GETS PUSHED TO ATL COAST STATES ON
TUE AS MODELS SHOW 100+ KT JET CARVING OUT UPR TROF OVR CNTRL CONUS.
LOOK FOR INCRG WAA CLDS AHD OF THIS TROF ON TUE AFT INTO EVNG. AVN
FCSTG RAPID CYCLOGENESIS AHD OF UPR TROF TUE EVNG AND DEVELOPING SFC
LOW TRACKS TO NR GRB BY 12Z WED. FCST TRACK BY 72 HRS COMES MORE IN
LINE WITH ECMWF/UKMET TRACK SOLN. HAVE SIDED MORE WITH THESE MODELS
IN LONGER TERM TRACK AND DISGARDED TO FAR WWD TRACK OF MRF. ECMWF 8H
LOW TO TRACK FM GRB TO NR SSM BY 12Z THU. WITH GIVEN TRACK HAVE
FCSTD SNOW FOR ALL WRN ZONES LATE TUE NIGHT INTO WED AND A MIX OF
RAIN AND SNOW FOR MNM-ALGER COUNTIES EWD WHERE BELIEVE SELY ONSHORE
FLOW FM LAKE MI WILL KEEP CRITICAL LLVL THCKNS WRMR
THERE.
LOOK FOR CHANGEOVER TO ALL SNOW BY LATE WED WITH DYNAMIC COOLING FM
VORT MOVG OVR AREA AND THEN CAA BEHIND LOW FOR WED NIGHT INTO THU.
PERIODICS IMPULSES TO BRING CHC OF LES SNOW THU INTO SUN WITH
FAVORED FETCH AREAS IN NWLY FLOW KEW-CMX AND
ALGER-LUCE.
.MQT...NONE.
VOSS
FXUS63 KDTX 122054 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
130 PM EST SUN DEC 12 1999
WILL UPDATE EXCEPT FOR FAR SOUTHEAST TO BEEF UP PRECIPITATION
WORDING A BIT...AS RECENT RADAR TRENDS SHOW MORE IN WAY OF
REFLECTIVITY...ESPECIALLY MOVING INTO SHIAWASSEE AND
LIVINGSTON WHERE SLEET INDICATED AND SOME SNOW BEING REPORTED.
NEWEST RUC SOUNDINGS SHOW MARGINAL SUPPORT FOR SNOW AND/OR SLEET
NORTH AND CENTRAL PART OF CWA MAINLY EARLY PART OF AFTERNOON...THEN
WARMING BOUNDARY LAYER A BIT LEANING TOWARD LESS SNOW/SLEET.
.DTX...NONE.
DWD
FXUS63 KGRR 121712 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1125 AM EST SUN DEC 12 1999
GOES-8 1KM VIS DATA SHOWING BAND OF MID/HI CLDS ASSOCIATED WITH UPR
LVL VORT LOBE PULLING EAST ACROSS CNTRL UP MI THIS MRNG. BACK EDGE
OF MID-HI CLDS ALONG A MQT-IMT LINE AT 1545Z CONFIRMED BY LOSS OF
DATA INDICATING DEPARTURE OF MID-HI CLDS ON KMQT WSR-88D VAD WIND
PROFILE AT 1516Z. BACK EDGE OF LGT SNOW/FLURRIES NOT FAR AHEAD
OF BACK EDGE OF CLDS... WITH 88D REFLECTIVITY COVERAGE AND
INTENSITIES DECREASING SINCE 15Z.
LATEST RUC SHOWING CONTINUED 850-500 MB LVL DRYING AS DRYER AIR
PER MPX/INL 12Z SOUNDINGS CONTINUES TO ADVECT SLOWLY EAST. SFC
STREAMLINE ANALYSIS SHOWING FLOW BECOMING SLGTLY MORE DIVERGENT
ACROSS THE U.P. SINCE 12Z IN RESPONSE TO SOME WEAK RIDING AHEAD OF
SFC LOW NR LAKE WINNIPEG. ALSO... WEAK DIFF NVA ALOFT WILL
ENHANCE SYNOPTIC SCALE SUBSIDENCE. DESPITE THESE FORCINGS HOWEVER A
CONSIDERABLE AMOUNT OF LOW LVL MOISTURE REMAINS TRAPPED UNDER THE LOW
LVL INVERSION ACROSS NRN WIS (WHERE CONSIDERABLE FOG/STRATUS FIELD
DVLPD OVRNGT) AND OVR LK SUP. XPECT THESE CLD FIELDS TO ERODE AT THE
EDGES ONLY SLOWLY THIS AFTN LEAVING A REAL HODGE PODGE OF SKY
CONDITIONS ACROSS THE U.P. FOR THE NEXT SVRL HRS.
AS A RESULT OF VARYING SKY CONDITIONS AND SNOW COVER...
TEMPS WILL ALSO VARY ACCORDINGLY... WITH GREATEST WARMING
EXPERIENCED COINCIDENT WITH GREATEST SUNSHINE... GENERALLY NORTH
AND WEST. SECTIONS OF THE EASTERN AND SRN U.P. STARTING OUT WARMER
HWVR.
.MQT...NONE.
ED F
FXUS63 KDTX 121550 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1050 AM EST SUN DEC 12 1999
SO FAR ONLY VERY ISOLATED REPORTS OF PRECIPITATION THIS
MORNING...THANKS TO EXTREMELY DRY SOUNDING THROUGH LOW LEVELS.
WITH WARMER UPSTREAM CLOUD TOPS AND LITTLE IN WAY OF UPSTREAM
PRECIPITATION BEING REPORTED...WILL CUT BACK POPS IN FAR SOUTHEAST
THIS AFTERNOON TO CHANCE AND MENTION FLURRIES AND/OR SPRINKLES
ELSEWHERE THIS AFTERNOON. 00Z SOUNDINGS GENERALLY VERY POOR IN
SATURATION OF LOW LEVELS THIS AFTERNOON...AND LATEST RUC VERY POOR
AS WELL THROUGH THIS AFTERNOON. PRECIPITATION TYPE VIA MODEL
SOUNDINGS AND THICKNESSES WOULD SUGGEST MIX NORTH AND MAINLY RAIN
SOUTH. EVAPORATIVE COOLING STILL A FACTOR TO CONSIDER THIS
AFTERNOON...THOUGH NOT EXPECTING ENOUGH PRECIPITATION TO BE MUCH OF
AN EFFECT...WET BULB TEMPERATURES ONLY SLIGHTLY RISING.
ALSO...SOUNDINGS SUGGEST THAT ICE CRYSTAL AVAILABILITY LIMITED THIS
AFTERNOON...DETERRING AN ALL SNOW FORECAST.
WITH GRADUALLY LOWERING CEILINGS AND LACK OF MUCH THERMAL
ADVECTION...TEMPERATURES SHOULD RISE ONLY A TAD THIS AFTERNOON.
UPDATING TO ALSO TWEAK TEMPERATURES UP JUST A TOUCH IN FAR
SOUTHEAST...WITH READINGS ALREADY FLIRTING WITH 40...AND TO ADJUST
WINDS A BIT.
.DTX...NONE.
DWD
FXUS63 KGRR 121517 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
945 AM CST SUN DEC 12 1999
LATEST RUC SEEMS TO HAVE DECENT HANDLE ON MID LEVEL MOISTURE WITH
SHORT WAVE CROSSING ND. THINK ANY PRECIP WILL BE NORTH OF OUR AREA
BUT WILL LEAVE IN THE MENTION OF FLURRIES IN AREAS TO NORTH.
SOUNDINGS AND TRAJ FORECASTS FROM LAST NIGHT SUGGEST SOME HIGHS AT
LEAST IN THE LOW 40S OVER PARTS OF S MN DEPENDING ON CLOUDS. WINDS
MAY NOT BE STRONG ENOUGH FOR GOOD MIXING THOUGH. MINOR ADJUSTMENTS TO
SOME WORDING AND TEMPS.
.MSP...NONE
RICHARDSON
mn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
910 PM CST SUN DEC 12 1999
SATELLITE IMAGERY SHOWS A DISTINCT CLEARING LINE MOVING INTO EXTREME
WESTERN PORTION OF FORECAST AREA. COMPARING 00Z AND 01Z IMAGERY TO
LATEST RUC AND INCOMING ETA...CLEARING LINES UP WELL WITH THE 60-65
PERCENT 85H MODEL RH. SHORT TERM MODEL TRENDS BRING CLEARING TO THE
NORTHWEST HALF OF THE FORECAST AREA BY 06Z AND TO ALL BUT THE SOUTH
CENTRAL COUNTIES BY 12Z. SOME LINGERING CLOUDS MAY HANG ALONG THE
OZARK PLATEAU...HOWEVER...WILL GENERALLY FOLLOW MODEL TRENDS AND
MENTION MOSTLY CLEAR OR CLEARING SKIES...ESPECIALLY NORTH OF I-44.
IN AREAS THAT DO CLEAR...WILL ALSO MENTION SOME FOG. VISIBILITY
ALREADY DOWN TO 5-6NM WHERE SKIES HAVE CLEARED IN SE KS. GROUND
MOISTURE FROM RECENT RAIN WILL AID IN SHALLOW FOG DEVELOPMENT.
UPDATED ZFP WILL BE OUT SHORTLY.
.SGF...NONE.
DSA
FXUS63 KLSX 122147 mo
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
427 AM CST SUN DEC 12 1999
LATEST ANLYSIS OR MTR DATA AND LAST NITES UPR SHWS WND SHFT LN ACR
CNTL NE FM SFC UP THRU H8. INVERTED TROF AXIS XNTDS FM NE TX IN CNTL
MO. RUC DATA AT 0800 UTC SHWS AREA OF H3 DVRGNC LINED UP FM SW TO NE
ACR SW TWO THIRDS OF CWA OVER TOP OF THIS INVERTED TROF AXIS WITH AT
LEAST ONE MORE 90 KT JET MAX TO MV THRU AS SRN PLNS SHRT WV TRACKS
EWRD. SRLY FLW IN LWR TROPOSPHERE NOT AS STG AS 24 HRS AGO AND
MODELS SHW LTL OR NO BNDRY LYR MSTR FLUX CNVGNC. IR LOOP THRU 0900
UTC SHWS NARROW AREA OF COOLING TOPS IN AFOREMENTIONED AREA OF
DVRGNC WITH LWRG CIGS AND VSBYS BLO 2 SM. MODELS MISSED THE MARK ON
SAT IN UNDER FCSTING MSTR FLUX CNVGNC IN BNDRY LYR AND AREAS -RA/-DZ
FORMED DURING THE PM. WITH LWR TROPOSPHERIC FNT/WND SHFT LN LIKELY
TO BE DRAPED ACR FCST AREA THIS AM INSERTED SPOTTY -DZ IN SW TWO
THIRDS. FG APPRS TO BE MORE OF AN AVIATION CONCERN ATTM AND LEFT OUT
OF ZFP.
LWR TROPOSPHERIC FRONTOGENETIC LIFT FCST TO RMN IN PLACE OVR SERN
CWA THUR 36 HRS THEREFORE DID NOT INTRODUCE ANY CLRG THRU TNGT. FTHR TO
NW ALLOWED FOR BRKS IN LO CLDS BY PM ACR NW AND TWRDS EVNG ALG MKC
IRK LN. INHERITED TEMP FCST OF WARMER NUMBERS ACR NW MO APPEARED TO
BE IN TOUCH SO USED IN AM PKG.
MODELS SUGGEST ATM IN STATE OF TRANSITION THRU FCST PRD. EVEN THOUGH
FRONTOGENTIC LIFT FCST TO VACATE RGN BY MON THERE DOES NOT APPR TO BE
SGFNT SUBSIDENCE BHD SYS FCST TO EXIT RGN. NOSE OF 120 KT JET FCST
TO DIVE IN INTER-MOUNTAIN RGN IN 48 HRS WHICH SHLD BE COMMENCEMENT
TO PTN CHG TO MORE PRONOUNCED WINT REGIME. MID/HIGH CLDS MAY CAUSE
SOME FLUCTUATION IN FCST MAX TEMPS NXT SVRL DAYS. CRNT FCST TEMPS IN
LN WITH LATEST AVBL GUIDANCE AND BASED ON PERSISTANCE AND READINGS
UPSTRM MADE LTL OR NO CHGS THRU FIRST 4 PRDS. MRF/SEF CAN RUNS
INDICATE STG PRORGRESSIVE SHRT WV TO TRACK ACR NATION LATER IN WEAK
WITH THREAT OF AT LEAST -SN OR MIXED PCPN. WITH STG CAA FCST
WED/THUR LIKE CRNT XTND TEMP FCST WHICH IS 8-10 DEG COOLER THAN
LATEST MRF GUIDANCE. STAYED WITH CHILLIER CRNT NUMBERS.
.EAX...
KS...NONE.
MO...NONE.
BODNER
E@ WD
mo
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
210 PM EST SUN DEC 12 1999
WRMFNT HAS INTRUDED INTO PTNS OF S CNTRL TN AT 18Z. H8 THETA-E RDG
PER THE RUC WAS THRU GLFMEX-MS-NW KY-OH WITH BEST ENHANCEMENT ON
SATPIX MAINLY JUST TO THE W WHILE CI SEEMS TO BE THINNING AS IT
APCHS SCHOHARIE VLY. SC WAS SHRINKING AWAY FM IMDT HDSVLY. WITH H3
JET CORE TO THE TUNE OF 175KTS OBSERVED ON KGRB SOUNDING PULLING
THRU UPR GRTLKS...UPR DIV COULD BE ENOUGH REMOVED TO SPARE THE FIRST
PD ANY PCPN MENTION WHICH IS IN LN WITH NGM/GEM SOLUTIONS AND AVN IS
NR EXTRM WRN FRINGE...ETA MAINTAINS ITS PACE FM 11/12Z COMPARISON.
FOR MON...MODELS HAVE SAME IDEA WITH RESPECT TO HANDLING OF H5 VOT
MAX APCHG ST LAWRENCE VLY...BUT NGM MAKES NWD PUSH WITH WRMFNT ABT
50-100 MI N OF OTHER MODELS. GEM IS DRIEST OF THE BUNCH AND WL SHAVE
POPS SLGTLY FM NGM VALUES. LOW LVLS START OUT BLO FRZG AND WL NEED
TO INCLUDE FZRA IN NRN VLYS...SRN ZONES MAY NOT HAVE AS WDSPRD FRZG
CONDS. MON NGT...FNT SEEMS TO GO QSTNRY AND PCPN MAKES SOMEWHAT OF A
SBND RETREAT AS SFC LOW APCHS OH. ETA EVEN DEPICTS SCNDRY WAVE OFF
MID ATLC CST...WL CHIP POPS BACK ANOTHER NOTCH. FOR TUESDAY...WL
NEED TO BRING POPS BACK TO AT LEAST LKLY WITH APCH OF UPR SYSTEM.
IN EXTENDED PD LONG WAVE TROF CONTS DIGGING ACRS MID COUNTRY WITH
LTL BIT OF RDGG TRYING TO TAKE HOLD DOWNSTREAM...WL LEAVE SOME
LEFTOVER MRNG PCPN FOR WED...THEN HAVE SHORT-LIVED IPVMT THEREAFT.
MCKINLEY/GJM
.ALB...NY ERN/VT EXTRM SRN/MA EXTRM WRN/CT NW...NONE.
FXUS61 KBGM 121855 ny
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
930 AM EST SUN DEC 12 1999
14Z SFC MAP SHOWS HI PRES OVER ERN NC AND EXTENDING SSE OFF THE
COAST. A TROF IS EVIDENT OFF THE SC COAST AS OBS ALONG COASTAL
STATIONS SHOWING NE WINDS WITH SE WINDS FOUND OFFSHORE AT 41004.
LATEST RUC SHOWS THIS FEATURE REMAINING OFF THE COAST AND WEAKENING
THIS AFTN. RUC ALSO KEEPS WINDS CONSIDERABLY MORE NE THIS AFTN THAN
EVEN THE ETA. WILL LEAN TOWARD THE RUC SOLN AND WITH APPROACHING
CLOUDS MAY HAVE TO TWEAK TEMPS DOWN A TAD. WILL WAIT FOR 10 AM TEMPS
TO MAKE FINAL CALL.
CWF...AS MENTIONED ABOVE WILL LEAN TOWARD RUC AND THEREFORE BE
SLOWER TO VEER WINDS E AND SE. OTHERWISE NO CHANGES.
.ILM...NONE.
MORGAN
nc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1040 AM EST SUN DEC 12 1999
RADAR AND SURFACE DATA SHOWS LIGHT RAIN HAS ADVANCED TO CENTRAL OHIO
THIS MORNING...FASTER THAN WHAT LATEST MESOETA AND RUC SHOWS.
MORNING PBZ SOUNDING SHOWS VERY DRY LOWLEVEL CONDITIONS. AM THINKING
ABOUT PUSHING UP MENTION OF LIGHT RAIN FOR EAST CENTRAL OHIO THIS
AFTERNOON. MAY EVEN ADD SPRINKLES FOR LATE AFTERNOON IN PITTSBURGH
AREA. AFTERNOON HIGH TEMPERATURE FORECAST IS TRICKY DUE TO STRONG
DEEP SURFACE INVERSION AND THIS POSSIBLE ONSET OF PRECIPITATION.
WILL GO CLOSE TO GUIDANCE FORECAST OF 50. ...GIORDANO
.PIT...NONE
FXUS61 KPHI 121507 pa
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MEMPHIS TN
810 PM CST SUN DEC 12 1999
AT 01Z...A SFC LOW WAS NEAR MCB W/ A WARM FRONT EXTENDING NE ALONG
A JAN-GTR-MSL ARC. MAIN BATCH OF RAIN HAS MOVED EAST OF AN OBION TO
SOMERVILLE TO SENATOBIA LINE. ETA/RUC BOTH SHOW BEST LIFT IN THE
295-310K LAYER ACROSS OUR ERN COUNTIES INTO MIDDLE TN OVNT. UVM WILL
BE MAXIMIZED NORTH OF WARM FRONT W/ STRONG LLJ (40KT AT BNA)
ORTHOGONAL TO SFC BOUNDARY. CURRENT PLAN IS TO ADJUST POPS GIVEN
LATEST RADAR TRENDS. HOWEVER...W/ SFC LOW LIFTING SLOWLY NE AND H5
LOW LIFTING TOWARD NE TX REDEVELOPMENT IS CERTAINLY POSSIBLE.
MID LEVEL LAPSE RATES SHOULD ALSO STEEPEN IN RESPONSE TO SYNOPTIC
SCALE HEIGHT FALLS AND MODEST MID LEVEL COOLING. FCST TEMPS LOOK ON
TRACK W/ ONLY MINOR...IF ANY...MINOR ADJUSTMENTS.
.MEM...NONE.
CBD
FXUS64 KOHX 130141 tn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
250 PM CST SUN DEC 12 1999
FORECAST QUANDRY(IES): TEMPERATURES
MEMAFDMEM ISSUED BY 2145Z...MEMZFPBNA ISSUED BY 2150Z
CURRENT ASOS/AWOS OBSERVATIONS...REGIONAL SATELLITE IMAGERY...
AND RADAR MOSIAC DATA SHOWING RAINFALL CONTINUING TO SPREAD EASTWARD
ACROSS CWA. LATEST LAPS/SURFACE ANALYSIS SHOWING COLD FRONT
POSITIONED EAST OF THE TN. RIVER WITH RAIN MOVING NE "QUICKLY"
AT 35 TO 40 MPH...WHILE THE TOTAL PCPN AREA IS "SLOWLY" SHIFTING E.
2Z UPPER LEVEL CHART ANALYSIS SHOWING "DEEP" TROUGHING OVER CENTRAL
U.S WITH LOW POSITIONED OVER SW TX. LATEST RUC ANALYSIS SHOWING
UPPER LOW "DRIFTING" NE. 3-HR PCPN ACCUMULATIONS ACROSS REGION ARE
AVERAGING LESS THAN 0.10 INCH WITH HIGHER AMOUNTS NOTED OVER
SOUTHERN KY.
12Z SUN MODEL RUNS REGIONALLY SIMILAR IN THEIR INITIALIZATION AND
PROGGED EVOLUTION THROUGH 00Z WED. 18Z SURFACE LOW PROGGED TO MOVE
NE FROM SW LA TO THE MID STATE BY OOZ TUE...AND INTO THE OHIO VALLEY
REGION BY 00Z WED. UPPER LEVEL LOW WILL ALSO "TRACK" NE AND PASS
OVER WESTERN KY BETWEEN 06Z-12Z TUE WITH FLOW BECOMING MORE ZONAL BY
00Z WED. PER 12Z SUN NCEP PROGNOSTIC DISCUSSION...SRN STREAM
HAS BEEN THE "BIG PLAYER" WITH STRONG SYSTEMS DIVING INTO THE SW AND
SRN PLAINS BEFORE EJECTING NEWD. WITH ABUNDANT GULF MOISTURE AND
STRONG INFLOW COMBINED WITH LARGE SCALE DYNAMICS WILL RESULT IN TRAILING
COLD FRONT CONVECTION WITH A LARGE SHIELDED OVERRUNNING RAINS TO THE
NORTH. ALSO IN AGREEMENT WITH NCEP DISCUSSION ON MODELS DEPICTING A
RATHER "IMPRESSIVE" 850 MB BAROCLINIC ZONE OVER THE MS.AND TN.
VALLEY/S TONIGHT PROVIDING A REGION OF ENHANCED RAINFALL AS A STRONG
LOW LEVEL JET INTERSECTS BOUNDRY. NCEP/S EXCESSIVE RAINFALL POTENTIAL
OUTLOOK EXPECTING A LONG DURATION RAINFALL EVENT DESPITE BEST LOW
LEVEL JET DYNAMICS MOVING EAST OF REGION MON. LOOK FOR WRAPARND
RAINS TO PERSITS NR THE LOW LEVEL CENTER WITH LGT-MDT RAINFALL
AMOUNTS WITH HEAVIEST RAINS OF 1.5-2.0 IN. POSSIBLE OVER CWA/S WEST
AND CENTRAL REGIONS. MODELS INDICATING SOME POTENTIAL FOR DECREASED
AIRMASS INSTABILITY BETWEEN 18Z MON-06Z TUESDAY WITH LI/S 0 TO -2,
OMEGA VALUES -1, SHOWWATER -2, AND K VALUES AROUND 30. LOOK FOR
CONVECTIVE POTETIAL TO DECREASE AFTER 06Z TUE WITH LINGERING CHANCE
POPS INTO THE EXTENDED PERIOD.
AS FOR THE TEMPERATURE FORECAST...WILL LEAN TOWARD WARMER NGM MOS
LOWS THROUGH PERIOD. WITH SOUTHERLY WINDS AND POSSIBLE WAA PATERN
DEVELOPMENT BY 00Z...WILL GO A FEW DEGREES WARMER THAN NGM MOS ON
HIGHS AND MORE IN LINE WITH BOUNDRY TEMPERATURE SCHEME VALUES.
WILL GO WITH COMPROMISE ON TUESDAY HIGHS.
PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY...
BNA 048/060/044/054 ++75
CSV 048/057/041/050 ++86
.BNA...NONE.
$$
14
JBW
FXUS64 KMEG 122031 tn
DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
900 PM CST SUN DEC 12 1999
BRISK NORTHWEST WIND THAT OCCURRED TODAY IN WAKE OF FRONTAL
PASSAGE THIS EARLY MORNING HAS CONSIDERABLY DRIED OUT THE
LOWER TROPOSPHERE OVER DEEP SOUTH TEXAS. DEWPOINTS ARE
GENERALLY IN THE 30S ACROSS THE RIO GRANDE VALLEY. WITH
MARKEDLY DRIER AIRMASS OVER THE AREA AND WITH WINDS CONTINUING
TO DIMINISH AS THE NIGHT PROGRESSES SOME RADIATIONAL COOLING
WILL OCCUR. OVERNIGHT LOWS WILL BE ABOUT 20 DEGREES COOLER WITH
THAN 24 HOURS AGO. CURRENT FORECAST HAS THIS WELL COVERED.
JUST MADE COSMETIC CHANGES TO FORECAST TO INDICATE WINDS AT
THE SURFACE DECOUPLING FROM THOSE ABOVE THE DECK. SURFACE WINDS
HAVE COME DOWN IN THE 10 TO 20 KNOTS RANGE WHILE KBRO VAD WIND
PROFILER SHOWED 30KT WINDS FROM THE 1 TO 6 KFT. WINDS SHOULD
DIMINISH TO NEAR 10 KNOTS OVERNIGHT. BOTH 18Z MESOETA AND 00Z
RUC SHOW TIGHTEST THERMAL PACKING AND TIGHTEST PRESSURE GRADIENT
GETTING PUSHED EASTWARD OVER THE COASTAL WATERS TOWARD MORNING AS
SURFACE HIGH OVER BIG BEND AREA DRAWS CLOSER SOUTH AND EAST TOWARD
OUR REGION.
MARINE...WILL KEEP THE SMALL CRAFT ADVISORY GOING OVERNIGHT IN ALL
MARINE ZONES PER ABOVE REASONING. THE WINDS OVER THE WATERS WILL
FINALLY BEGIN TO RELAX LATER MONDAY.
SYNOPTIC/MESO...CORDERO (64)/HMT...VEGA
WEB PAGE...WWW.SRH.NOAA.GOV/BRO
.BRO...SMALL CRAFT ADVISORY GMZ130-150-155-170-175.
FXUS64 KEWX 130232 tx
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
830 PM CST SUN DEC 12 1999
LARGE SHIELD OF WRAP AROUND CLOUDS EVIDENT ON SATELLITE. WEDGE OF
PRECIP FROM NEAR CLL TO SEP TO AUS SPREADING TOWARD FA AS UPPER LOW
MOVES SLOWLY EASTWARD. ETA/NGM/AVN AND TO A LESSER EXTENT THE RUC
DEPICT ACCUMULATIONS OVER MAINLY THE NORTHERN HALF OF THE CWA AND CAN
SEE NO REASON TO DISAGREE. CURRENT PACKAGE SHOWS 30 POPS IN NORTHERN
TIER/20 CENTRAL. TEMPERATURE FALL HAS BEEN SLOWED BY THE OVERCAST
SKIES...SO WILL PROBABLY NUDGE TEMPS UP A TAD IN THE NORTHERN AND
CENTRAL ZONES. MAY ALSO BUMP POPS TO 40 IN THE NORTHERN TIER BASED
ON THE CURRENT RADAR AND SATELLITE TREND. WILL PROBABLY LEAVE SCA IN
PLACE OR EXPAND IT TO INCLUDE GLS BAY. MVFR SHOULD PREVAIL THROUGH
MOST OF THE EVENING WITH IMPROVEMENT TOWARD MORNING.
45/40/TOM
.HGX...SMALL CRAFT ADVISORY MATAGORDA BAY...FOR THE COASTAL WATERS
FROM MATAGORDA TO HIGH ISLAND AND OUT TO 60 NM.
PRELIMS...
CLL EU 042/057 038/068 037 430
IAH EU 046/059 039/068 040 220
GLS BU 052/059 049/068 047 -00
FXUS64 KHGX 122132 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
955 AM CST SUN DEC 12 1999
GOES IR IMAGERY SHOWS UPPER LOW OVER FAR WEST TX...MOVING INTO THE
TRANS PECOS REGION. A SURFACE WARM FRONT WAS THE FOCUS OF CONVECTION
OVER EAST TX THIS MORNING...WHILE NORTHWEST LOW LEVEL WINDS WERE
SPREADING DRIER AIR INTO WC TX. KSJT/KDYX RADARS WERE SHOWING
SCATTERED 10-20 DBZ MID LEVEL ECHOS ACROSS WC TX. PRECIP IS HAVING A
DIFFICULT TIME MAKING IT TO THE GROUND...AS THE DRY AIRMASS HAS
UNDERCUT THE MID LEVEL LIFT. KSJT VAD WIND PROFILER SHOWS NORTH
WINDS TO 10 KFT MSL.
12Z RUC PLACES THE 500 MB TROF JUST EAST OF THE CWFA AT 00Z. WITH
LOW LEVEL DEWPOINTS FALLING INTO THE 20S...ANY WRAP AROUND PRECIP
WILL BE LIGHT AND ENDING BY MID EVENING. WITH 850-700MB THICKNESSES
AND 850 MB TEMPS NEAR 1C...A FEW FLURRIES ARE POSSIBLE ACROSS THE
NORTH.
ZONE UPDATE TO FOLLOW.
14
FXUS64 KEWX 121326 tx
SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
720 AM CST SUN DEC 12 1999
SURFACE LOW AND ASSOCIATED FRONTS HAVE EXITED THE EWX CWA TO THE
EAST TAKING THE THUNDERSTORMS WITH THEM. UPPER LOW KEEPS ON MOVING
EAST AND WAS CENTERED OVER THE DAVIS MOUNTAINS. EXPECT AND NEW RUC
AND ETA RUNS INDICATE IT WILL TRACK ALONG THE NORTHERN EDGE OF THE
EWX CWA. LOWER LEVELS COOLING AND LAPSE RATES BECOMING LESS
FAVORABLE FOR WIDESPREAD THUNDER. THUS...WILL UPDATE ZONES TO REMOVE
MENTION OF SAME. SHORT-TERM CAN HANDLE ANY ISOLATED POSSIBILITIES.
WILL ALSO MAKE MINOR TWEAKS TO THE FIRST PERIOD BASED ON CURRENT
TRENDS AND MODEL RUNS.
.EWX...NONE.
SYN...04/MESO...18.
FXUS64 KFWD 121134 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
856 PM CST SUN DEC 12 1999
...MAIN FORECAST CHALLENGES OVERNIGHT ARE FOG AND TEMPERATURES.
SATELLITE FOG/STRATUS PRODUCT SHOWS AND AREA OF WIDESPREAD LOW
CLOUDS AND FOG OVER CENTRAL WISCONSIN. EDGE OF FOG CAN BE
SEEN ADVANCING TO THE SOUTHWEST DURING THE PAST COUPLE OF
HOURS. OBSERVATIONS INDICATE THAT VISIBILITIES ARE AT A QUARTER MILE
OR LESS IN MANY CITIES. FOG ALREADY DEVELOPING IN THE WISCONSIN RIVER
VALLEY IN SOUTHWEST WISCONSIN AND TEMPERATURE DEWPOINT SPREAD A
DEGREE OR LESS IN MOST OF THE MISSISSIPPI RIVER VALLEY ALREADY. VERY
WEAK TROUGH APPROACHING FROM THE WEST...BUT PRESSURE GRADIENT WEAK
OVERALL. TEMPERATURE IN MEDFORD HAS ONLY VARIED BY A DEGREE DURING
THE DAY.
MODEL SOUNDINGS FROM 00Z RUC INDICATES THE INVERSION WILL CONTINUE
TO INCREASE OVERNIGHT AND THE BOUNDARY LAYER FLOW VERY LIGHT.
SURFACE PRESSURE GRADIENT FIELD INDICATES WINDS WILL REMAIN 5 KTS OR
LESS ACROSS THE EASTERN TWO THIRDS OF THE FORECAST AREA. RUC
FORECASTS THE BOUNDARY LAYER MOISTURE WILL INCREASE TO SUFFICIENT
LEVELS FOR FOG INTO THE MISSISSIPPI RIVER VALLEY DURING THE NIGHT.
DENSE FOG CRITERIA ALREADY MET IN CENTRAL WISCONSIN ZONES. EXPECT
DENSE FOG TO DEVELOP IN REST OF WISCONSIN AND NEAR MISSISSIPPI RIVER.
WILL ISSUE A DENSE FOG ADVISORY FOR ALL WISCONSIN COUNTIES AND
EXTREME EASTERN SECTIONS OF MINNESOTA AND IOWA COUNTIES. WILL KEEP
TEMPERATURES STEADY IN AREAS WHERE DENSE FOG HAS ALREADY DEVELOPED.
WILL RAISE TEMPERATURES A BIT ELSEWHERE WITH EXPECTED DEVELOPMENT
OF FOG AND STABILIZATION OF TEMPERATURES.
.LSE...DENSE FOG ADVISORY...FOR TONIGHT AND MONDAY MORNING...WEST
AND CENTRAL WI...AND EXTREME EASTERN SE MN AND NE IA...WIZ017...
029...032>034...041>044...053>055..061...MNZ079...088...096...
IAZ011...030
NELSON
COORDINATED WITH KGRB...KMKX...AND KMPX
FXUS63 KGRB 130251 wi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
342 AM EST MON DEC 13 1999
SFC HIGH AND WEAK GRADIENT RESIDES OVER NRN LOWER MI EARLY THIS
MORNING...WITH A WEAK VORT LOBE ROTATING THROUGH ERN UPR MI
RESULTING IN ONLY SCT-BKN MID CLOUDS. LOW LEVEL MOISTURE HAS BECOME
TRAPPED BELOW THE INVERSION OVERNIGHT ACROSS MUCH OF ERN UPR AND NW
LOWER MI...THUS LOW CLOUDS AND PATCHY FOG HAS DEVELOPED. RESIDUAL
SCT-BKN MID CLOUD DECK ACROSS NE LOWER MI HAS ALLOWED FOR JUST
ENOUGH RADIATIONAL COOLING TO DEVELOP PATCHY FOG AS WELL.
PERSISTANCE OF LOW CLOUDS AND FOG THIS MORNING IS THE MAIN SHORT
TERM FORECAST CONCERN. ATTENTION THEN TURNS TOWARD POPS FOR SRN
SECTIONS OF THE CWA TUESDAY AFTERNOON AS A SFC LOW DEVELOPS OVER THE
OHIO VALLEY AND RIDES NE TOWARD NEW ENGLAND.
00Z MODELS AGREE WITH STRENGTHENING HIGH PRES OVER MI THROUGHOUT THE
DAY. MODEL SOUNDINGS SHOW A THIN LAYER OF LOW LEVEL MOISTURE TRAPPED
BELOW THE INVERSION THIS MORNING. NGM AND AVN HAVE NOT PICKED UP ON
THIS FEATURE AS WELL AS THE ETA AND LATEST RUC. DESPITE RATHER LIGHT
WIND FIELDS AND LOW SUN ANGLE FOR THIS DECEMBER DAY...LOW LEVEL
MOIST LAYER IS THIN ENOUGH TO MIX OUT SHORTLY AFTER SUNRISE. AND BY
THEN...RESIDUAL MID CLOUD SHOULD HAVE EXITED TO THE E AS WELL.
THUS... WILL CONTINUE A MOSTLY SUNNY FORECAST...WITH A MENTION OF
ADDITIONAL CLOUDINESS AND PATCHY FOG EARLY IN THE DAY. LIGHT SE/E
FLOW BEGINS ON THE BACKSIDE OF THE SFC HIGH LATER TONIGHT...BUT DRY
AIR AND SUBSIDENCE WILL MAINTAIN PARTLY TO MOSTLY CLEAR SKIES.
SFC LOW FURTHER DEVELOPS IN THE OHIO VALLEY OVERNIGHT AND HEADS
NE...WITH THE NW EDGE OF THE LIFT AND MOISTURE ASSOCIATED WITH THE
SYSTEM SKIRTING SE SECTIONS OF THE CWA. WEAK 850-700MB Q-VECTOR
CONVERGENCE WAS NOTED FROM HARRISVILLE TO HOUGHTON LAKE...AS WAS AN
ENHANCED AREA OF LOW AND MID LEVEL MOISTURE IN THIS REGION. WILL
MAINTAIN MENTION OF LOW CHANCE POPS FOR THIS REGION FOR TUESDAY
AFTERNOON...BUT ONLY SPRINKLES FOR SW SECTIONS OF THE CWA DUE TO
LAKE OF SUFFICIENT MOISTURE AND LIFT FOR MEASURABLE PRECIP.
.APX...NONE.
EME
FXUS63 KDTX 130834 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
300 AM CST MON DEC 13 1999
STRATUS AND FOG SEEN IN SATELLITE ANIMATION ACROSS WEST CENTRAL
WISCONSIN APPEARS TO BE NEARLY STATIONARY. RUC MODEL INDICATES DRIER
WESTERLY FLOW CURRENTLY INTO THIS AREA. IT SHOULD REMAIN CONTAINED
UNTIL IT DISSIPATES AROUND MID MORNING. BROAD 500 MB RIDGE IS
FORECAST TO MOVE ACROSS OUR COUNTY WARNING AREA TODAY. SHOULD SEE
ONLY INCREASING HIGH CLOUDS FROM THE WEST. DUE TO WARM ADVECTION AND
SUNSHINE...THINK THE MODEL OUTPUT STATISTICS MAY BE A LITTLE LOW.
THE ETA AND AVN MODELS ARE SIMILAR THROUGH 48 HOURS. NEITHER
DEVELOPS A LOWER LEVEL LOW PRESSURE AREA AND THE MIDDLE LEVEL
TEMPERATURE ADVECTION IS PRETTY WEAK. NEVER THE LESS...THE MIDDLE
LEVEL TROUGH IS RATHER SHARP...THE THICKNESS VALUES ARE FORECAST TO
DROP RAPIDLY ABOUT THE TIME PRECIPITATION IS ANTICIPATED AND THE 200
MB WARM ADVECTION...AROUND 6 DEGREES...HINTS THAT SOME SNOW
ACCUMULATIONS ARE POSSIBLE. THINK A 1 TO 2 INCH EVENT IS REASONABLE
TO EXPECT. 3 INCHES WOULD BE THE WORST CASE SCENARIO AND MOST AREAS
LIKELY TO SEE LESS THAN AN INCH.
.MSP...NONE
WH
FXUS63 KDLH 130809 mn
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
310 AM PST MON DEC 13 1999
MODERATE WEST NORTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS SOUTHERN
CALIFORNIA MUCH OF THE WEEK WITH PERIODS OF GUSTY WINDS IN THE
MOUNTAINS AND DESERTS AND BRIEF PERIODS OF GUSTY WINDS BELOW PASSES
AND CANYONS. A WEAK COASTAL EDDY WILL BRING PATCHY NIGHT AND
MORNING LOW CLOUDS AND DENSE FOG TO THE BEACHES THROUGH TUESDAY
MORNING. SEASONAL TEMPERATURES ARE EXPECTED ALONG THE COAST WITH
SEASONAL TO SLIGHTLY BELOW NORMAL TEMPERATURES INLAND.
RELYING MOSTLY ON AFOS AND INTERNET AS LTL OTHER THAN SATELLITE
IMAGERY HAS UPDATED IN AWIPS SINCE 12Z. SATELLITE IMAGERY SHOWS
LATEST PAC SHORTWAVE OVR NV CONTINUING TO TRACK INLAND TO THE EAST
SOUTHEAST...IN LINE WITH THE 12Z MDL FORECASTS. UNLIKE WITH RECENT
SYSTEMS...UPSTREAM RDGG IS LACKING...HENCE SYS SHOULD BE MORE
PROGRESSIVE WITH LESS TRAILING SURFACE HIGH PRESSURE OVER THE GREAT
BASIN WITH LESS POTENTIAL FOR STRONG OFSHR WINDS FOR SRN CA.
HOWEVER...BAND OF MDT-STG WNWLY FLOW ALF ALG AND TO THE N OF SRN CA
WL SUPPORT GUSTY WINDS IN THE MTNS AND DESERTS AND A BRIEF PD OF
OFSHR WINDS FOR SRN CA...PEAKING TUE MORNING WITH OFSHR WINDS
APPROACHING WAD CRITERIA FOR THE WINDIEST LOCATIONS LATE TONIGHT
THRU TUE MORNING.
COAMPS AND RUC SHOW A WK CSTL EDDY THIS MORNING...DISSIPATING
TODAY...THEN REFORMING TONIGHT. AT 11Z (3 AM)...FOG PRODUCT SHOWED
EXTENSIVE STRATUS FIELD ALG THE CNTRL CA CST AND WELL OFF THE SRN CA
CST WITH A FEW PATCHES ALG THE LOS ANGELES COUNTY CST AND OFF THE
ORANGE COUNTY CST. EDDY CRCLN SHOULD HELP TO REINFORCE ELY DRAINAGE
IN SAN COUNTY WITH ONLY PATCHY STRATUS NR SAN COUNTY BEACHES THIS
MORNING. AREAS OF STRATUS THIS MORNING SHOULD BE CONFINED TO NRN
ORANGE COUNTY AND SRN LOS ANGELES COUNTY AS STRATUS OVR THE CSTL
WTRS MOVG N TO NW ON THE EAST SIDE OF THE EDDY CRCLN INTERSECT THE
NWWD JUTTING COASTLINE. 04Z HIGH RESOLUTION ACARS SOUNDING FM LGB
SHOWED THE MARINE INVERSION BASE AOB 500 FT...HENCE POTENTIAL FOR
DENSE FOG...ALSO SUPPORTED BY OBSERVATIONS FM LAX. MORE EXTENSIVE
STRATUS FIELD LIKELY FOR SRN CSTL SXNS TONIGHT THRU EARLY MON
MORNING.
EXTENDED...MDLS SHOW LTL CHANGE IN THE LONGWAVE PATTERN OVR THE ERN
PAC AND WRN NOAM FOR MUCH OF THE WEEK...HENCE PDS OF GUSTY WINDS IN
THE MTNS AND DESERTS...BRIEF PDS OF GUSTY OFSHR WINDS BLO PASSES AND
CANYONS...AND SEASONAL TEMPERATURES AT THE CST WITH SEASONAL TO
SLIGHTLY BLO NORMAL TEMPERATURES INLAND. MRF 6-10 DAY MEAN SHOWS
SOME AMPLIFICATION/RETROGRESSION OF THE PATTERN OVR THE ERN PAC/WRN
NOAM (I.E. ...COOLER AND CONTINUED BREEZY FOR SRN CA) LATE WEEKEND
THRU THE MIDDLE OF NEXT WEEK.
SAN 000
.SAN...NONE.
MARTIN
ca
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
1000 AM EST MON DEC 13 1999
SYNOPSIS:
A WEAK COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EARLY TONIGHT. THEN HIGH PRESSURE WILL REBUILD ACROSS NORTHERN NEW
ENGLAND ON TUESDAY.
TECHNICAL DISCUSSION:
CURRENT FORECAST LOOKS IN GOOD SHAPE. BASED ON LATEST RUC TEMP FIELDS
(SFC,BL,925MB) WILL SPLIT ZN 10 FROM 1/3/4 AND MENTION MIXED PCPN FOR
LOWER ELEVATIONS AND CONTINUE WITH SNOW FOR HIGHER ELEVATIONS. WITH
THICK CLOUD COVER AND PCPN...TEMPS WILL BE HARD PRESSED TO MOVE MUCH
DURING THE AFTERNOON. CURRENT FORECAST MAXES TEMPS LOOKS GOOD.
COASTAL WATERS:
WIND IS QUIET OVER THE WATERS AND EXPECT THE SAME UNTIL FRONT MOVES
SOUTH AND SURFACE HIGH GRADUALLY BUILDS IN. BNDRY LYR WINDS INCREASE
DURING TUE AND THIS IS REFLECTED IN CURRENT CWF.
CAR OB 035/027 032/019 030 0477- 322/444/01/N
BGR WB 042/031 038/023 034 04541 332/444/00/N
.CAR...NONE.
FITZSIMMONS
me
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1115 AM EST MON DEC 13 1999
VISIBLE STLT AND NORTHERN MICHIGAN SURFACE OBSERVATIONS ARE
SHOWING GENERALLY MOSTLY SUNNY SKIES NOW FROM THE STRAITS SOUTH.
RUC MODEL DATA SHOWING A SURFACE HIGH PRESSURE RIDGE CURRENTLY
OVER THE GREAT LAKE REGION... WITH A WEAK UPPER LEVEL RIDGE EXPECTED
TO DEVELOP DURING THE AFTERNOON.
THE AREA OF CLOUDS OVER EASTERN WISCONSIN AND EAST UPPER MICHIGAN
ARE IN LINE WITH AN AREA OF 850/700 MB QVECTOR FORCING... IN THE BASE OF
AN EASTWARD MOVING 500 MB TROF. THIS FORCING QUICKLY DIMINISHES THIS
AFTERNOON OVER WISCONSIN AND EAST UPPER.
THEREFORE WILL WORD EAST UPPER MICHIGAN AS BECOMING PARTLY SUNNY.
FOR NORTHERN LOWER WILL GO WITH MOSTLY SUNNY.
.APX...NONE.
SWR
mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
950 AM EST MON DEC 13 1999
SURFACE OBSERVATIONS OVER EAST UPPER MICHIGAN SHOW AREAS OF LOW CLOUDS
AND FOG. ANJ CURRENTLY REPORTING 3/4SM BR OVC004...CIU IS 1/4SM FG
OVC001 AND ESC IS 3SM BR OVC002. RUC MODEL SOUNDINGS ACROSS EAST UPPER
SHOW A SHARP INVERSION JUST OFF THE SURFACE TRAPPING LOW CLOUDS AND FOG
THIS MORNING. MODEL SOUNDINGS SHOWING LOW LEVELS DRYING OUT BETWEEN 16Z
AND 18Z.
THE LATEST 3.9U IR STLT LOOP AND SURFACE OBSERVATIONS FROM NORTHERN
LOWER...STILL SHOWING AN AREA OF LOW LEVEL MOISTURE LINGERING OVER THE
SOUTHWEST PORTIONS OF THE FORECAST AREA. RUC MODEL SOUNDINGS FROM THIS
AREA SHOW DRYING IN THE LOWEST LAYERS BETWEEN 16Z AND 18Z.
THEREFORE WILL DO A QUICK UPDATE TO REFLECT THE CURRENT LOW CLOUD
AND FOG FOR EAST UPPER AND CLOUDS OVER NORTHERN LOWER.
.APX...NONE.
SWR
mi
NORTHERN GREAT BASIN FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ELKO NV
400 AM PST MON DEC 13 1999
COLD FRONT NOW IN SOUTHWEST IDAHO EXTENDING TO JUST EAST OF RENO.
WATER VAPOR AND INFRARED PICS SHOW LEFT FRONT QUADRANT OF STRONG JET
STREAK NOW IN NORTHEAST NEVADA AND 500MB TROUGH AXIS IN WESTERN
NEVADA. KLRX RADAR SHOWS MESOSCALE BAND OF HEAVY SNOW ALONG COLD
FRONT FROM SOUTHWEST IDAHO TO EASTERN HUMBOLDT COUNTY. INFRARED
ENHANCEMENT CONTINUES TO INTENSIFY. HAVE ISSUED SNOW ADVISORIES FOR
EASTERN ZONE 30...ZONE 31 AND ZONE 34 FOR THIS MORNING. WILL HAVE TO
WATCH FOR POSSIBLE ENHANCEMENT FURTHER SOUTH ALONG THE COLD FRONT.
RUC MODEL HAS INDICATED NEGATIVE LIS OF -2 TO -4 IN ELKO COUNTY SO
THUNDERSNOW IS POSSIBLE ESPECIALLY CONSIDERING 30 TO 40 DBZ RETURNS
ALREADY. BAND OF HEAVY SNOW IS NARROW AND MOVING FAIRLY QUICKLY SO
WILL NOT ISSUE WINTER STORM WARNING BUT WILL MONITOR.
DYNAMICS AND COLD FRONT WILL MOVE INTO UTAH LATE THIS MORNING ENDING
THE THREAT OF HEAVY SNOW. SNOW SHOWERS WILL PREVAIL THIS AFTERNOON
WITH STEEP LAPSE RATES EVIDENT ON FORECAST SOUNDINGS. DIRTY RIDGE
BUILDS IN WITH WAA FROM NORTHERN NEVADA NORTHWARD FOR TUESDAY. ALSO
WEAK SHORTWAVE IN NORTHWEST FLOW QUICKLY MOVES THROUGH THE CWA ON
TUESDAY...SO WILL SEE MOSTLY CLOUDY CONDITIONS ON TUESDAY WITH
FLURRIES IN THE NORTH.
EXTENDED: FLAT RIDGE HOLDS IN PLACE FOR THE PERIOD WITH WAA AND
SHORTWAVES EMBEDDED IN THE FLOW TO OUR NORTH. CLOSE ENOUGH FOR
PARTLY CLOUDY CONDITIONS THROUGH THE PERIOD WITH ABOVE NORMAL HIGHS.
.EKO...SNOW ADVISORY THIS MORNING ZONE 30...31 AND 34.
FXUS65 KVEF 131115 nv
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
945 AM EST MON DEC 13 1999
BROAD UPWARD VERTICAL MOTION CONTINUES OVER MOST OF FORECAST AREA
THIS MORNING WITH GOES WATER VAPOR LOOP INDICATING CONTINUED
ENHANCEMENT AND LIFT ALONG THE SPINE OF THE APPALACHIANS FROM
NORTHERN ALABAMA INTO WEST VIRGINIA. MOST PERSISTENT AND HEAVIEST
RAIN IS OCCURRING IN VICINITY OF A WEAKENING 35 KT 850 MB LOW-LEVEL
JET. TO THE NORTH...UPPER SYSTEM IS SHEARING SOMEWHAT AND RESULTING
DRY PUNCH OF AIR AT THE MIDLEVELS IS CLEARLY EVIDENT PROGRESSING
EAST AND NORTHWARD OVER MICHIGAN AND INTO NORTHWEST OHIO. ETA/RUC
INDICATE LOW LEVEL JET WEAKENING DURING THE DAY AND EXPECT RA TO
BECOME MORE SHOWERY AS STRONGER SOUTHWEST ONTARIO WAVE LIFTS
NORTHEASTWARD.
HOWEVER...2 WEAKER SHORTWAVES EMBEDDED WITHIN THE GENERALLY WEAK
SOUTHWEST FLOW ALOFT WILL KEEP THE RAIN AND SHOWERS GOING THROUGHOUT
THE DAY. CURRENT 88D RADAR MOSAIC SHOWS RAIN ECHOES FILLING IN
ACROSS SOUTHWEST PA AHEAD OF THE NEXT WEAK SHORTWAVE...MORE SHOWERY
IN CHARACTER. LOCAL COLD AIR BRIEFLY TRAPPED IN VALLEYS MAINLY NORTH
OF STATE COLLEGE THIS MORNING HAS BEEN MODIFIED BY THE FALLING RAIN
AND LOCATIONS WHICH HAD EARLIER REPORTED SPOTTY FREEZING RAIN HAVE
CHANGED OVER.
MAIN CHANGES THIS MORNING WILL BE TO CLEAN UP THE MORNING WORDING
AND FRESHEN PRECIPITATION CHARACTER FOR THIS AFTERNOON. EXPECT MORE
SHOWERY BUT LIGHT RAINFALL THIS AFTERNOON...ESPECIALLY ACROSS THE
NORTHWESTERN THIRD OF THE CWA.
CONCERNS FOR THE AFTERNOON PACKAGE WILL FOCUS ON POTENTIAL FREEZING
PRECIPITATION ACROSS THE NORTH TONIGHT AS RUC WET BULB ZEROES
ALREADY DROP BELOW ZERO BY 21Z NEAR ERI. EXPECT THIS TREND TO
CONTINUE INTO NRN PA OVERNIGHT WITH BUFKIT TIME HEIGHT CROSS
SECTIONSINDICATING POTENTIAL FOR ICING TO OCCUR FROM NRN PA INTO THE
SOUTHERN TIER OF NEW YORK TONIGHT AS MORE PLENTIFUL MOISTURE SURGES
NORTHWARD AHEAD OF MAIN SOUTHEAST U.S. WAVE. MORE ON THIS LATER.
.CTP...NONE.
DEVOIR
pa
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1054 AM EST MON DEC 13 1999
HI PRESS TO REMAIN OVR QUE TODAY AND TONITE...AS A STORM SYS MOVES UP
OUT OF THE SE U.S. AND INTO THE MID-ATLANTIC REGION. UPR LVL TROF TO
MOVE FROM THE EASTERN GREAT LKS REGION ACRS FA TODAY AND INTO THIS
EVENING.
ETA SHOWS WK H85 WAA BRIEFLY TAKING PLACE ACRS SRN VT TODAY AT AROUND
18Z. ALSO...925 MB TEMPS BLO ZERO ALL DAY TODAY ACRS MUCH OF THE FA.
UPSTREAM OBS IN CANADA SHOW THE PCPN FALLING AS SN...WITH -SN BEING
REPORTED AT MSS/OGS ATTM. DEW PTS ACRS FA ARE ALL BLO FREEZING...
SO ANY PCPN THAT FALLS SHOULD BE MOSTLY OF THE SOLID TYPE THIS
AFT. PCPN IN THE SOUTH THIS MORNING HAS BEEN MOSTLY ALOFT WITH PRETTY
HI CIGS AND FEEL THAT CHC FOR ANY EXTENDED PERIOD OF FZRA IS VERY
LOW...SO WILL DROP WSW FOR SRN VT ZONES WITH THE MORNING UPDATE. ALY
IN AGREEMENT BY THE LOOKS OF THEIR WRKZFP.
BACK EDGE OF ENHANCED CLDS IN IR SAT PIX TO MOVE THRU THE ST LAW
VLY BY AROUND 18Z...THE CHAMP VLY BY AROUND 20Z...AND
EASTERN/SOUTHERN VT AFT 22Z.
09Z RUC SHOWS MAX TEMPS IN THE 30S TODAY WITH ANY PCPN AMOUNTS BEING
VRY LT ACRS FA. JUST A FEW TWEAKS TO TEMPS BASED ON CURRENT TRENDS.
LATER PERIOD CHANGES ARE MAINLY COSMETIC.
WORK ZONES GONE...REAL ZONES TO QUICKLY FOLLOW.
.BTV...NONE.
MURRAY
vt