AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 940 PM CST FRI DEC 24 1999 MAIN CONCERN FOR EVEN UPDATE WL BE FOG/CLOUD TRENDS AND TEMPS. WATER VAPOR IMAGERY SHOWS UPR LVL RDG...SPCLLY NRN PTN...MAKING GOOD EWD PROGRESS. CLOSEST SGFNT SHRT WV DIVING INTO BASE OF LG WV TROF THRU GULF CST STATES SO LTL DYNAMIC FORCING NRBY. HWVR DECENT ISENT LIFT IN PLACE PER 00Z H85 ANLYS AND 295/300K SFCS OF 00Z RUC BUT LACK OF MSTR WL PRECLUDE MUCH IN THE WAY OF PCPN. ONLY CONCERN WOULD BE FRZG DRZL WHICH MAY AFFECT EXTRM NRN FA AS MSTR MUCH DEEPER N PER KMPX SOUNDING. MOIST LYR QUITE A BIT THINNER OVR CNTRL SXNS HWVR SO WITH VSBYS STILL AOA 4SM WL NOT ADD MENTION ATTM. LATEST 11-3.9 MICRN IMAGERY SHOWS LOW CLOUDS VERY WELL EXTENDING FM JUST N OF KCSQ FARTHER NWD TWRD KEST AND KMCW. EXTRAPOLATION OF BACK EDGE WOULD PLACE CLRG LN TO FAR ERN PTNS OF FA BY 07-08Z. RECENT TEMP TRENDS BHND CLRG LN POINT TWRD A GRDL TEMP DROP EVEN THOUGH DECENT WRM ADVCTN IS IN PLACE JUST ABV SFC. WITH SNW COVER THIS IS LIKELY JUST INCRG THE INVERSION TIL SFC WRMFNTL PASSAGE WHICH MAY WAIT TIL TMRW. 03Z SFC ANLYS SHOWS FNT STILL THRU NE WITH LTL MOVMT IN PAST SVRL HRS. THUS WENT WITH SKIES CLRG OVNGT AND PATCHY FOG DVLPG. INVERSION MAY BE JUST THIN ENOUGH WITH PLENTY OF DRY AIR ALF TO PRECLUDE MUCH MORE THAN PATCHY FOG. FOG DVLPMT NOT IMPRESSIVE ATTM EVEN OVR DENSER SNW PACK OF W CNTRL IA. ALSO LOWERED OVNGT TEMPS AS READINGS STILL SLOWLY FALLING AHD OF WRMFNT. .DSM...NONE SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1100 AM EST FRI DEC 24 1999 FORECAST CONCERNS TODAY ARE DIMINISHING LES AND MAX TEMPS. LATEST SAT AND 88D TRENDS SHOW LES EVENT CONTINUING TO WIND DOWN ACROSS THE UP. VIS AT IWD HAS BEEN AT 10SM FOR A FEW HOURS NOW...AND CMX HAS GONE SCT020. A FEW LES BANDS CONTINUE ACROSS FAR EASTERN LAKE SUPERIOR INTO ALGER/LUCE/SCHOOLCRAFT COUNTIES. HOWEVER... RETURNS HAVE BEEN UNDER 28DBZ WITH A CONTINUED DISORGANIZATION OF BANDS. ISQ AND ERY OBS STILL SHOWING -SN IN VIS FROM 1/2 TO 2SM. VWP CONTINUES TO SHOW CLOUD TOPS AROUND 7K FEET...WHILE RUC FORECAST SOUNDINGS SHOW LOWERING INVERSION LEVELS AND LOWERING RH DURING THE DAY. 12Z APX SOUNDING SHOWED INVERSION AROUND 850MB (4500FT) WITH DRIER AIR BELOW INVERSION COMPARED TO LAST NIGHTS SOUNDING. RUC ALSO SHOWS LOW LEVEL WINDS BACKING FROM N TO W AS SFC HIGH PASSES TO OUR SOUTH AND LAKE INDUCED TROF WEAKENS THIS AFTERNOON. 850MB TEMPS WARM A COUPLE DEGREES DURING THE DAY AS WELL...THOUGH MAINTAINS ADEQUATE DELTA/T FOR CLOUDS BEFORE ONSHORE COMPONENT DIES. THESE FACTORS POINT TOWARD CONTINUED WEAKENING OF LES OVER EASTERN UPR THIS AFTERNOON. ENOUGH LOW LEVEL MOISTURE AND LAKE INFLUENCE FOR VARIABLE CLOUD COVER TO REMAIN OVER WEST/CENTRAL LAKE SUPERIOR COUNTIES. WILL MAINTAIN MOSTLY SUNNY WORDING FOR SOUTHERN COUNTIES BASED ON SAT TRENDS. WILL ADJUST TEMPS DOWNWARD SLIGHTLY FOR A FEW LOCATIONS BASED ON CURRENT READINGS AND LAMP GUIDANCE. IMT ONLY -6F AT 15Z. OTHERWISE...MAINLY FRESHENED WORDING FOR ZONES INCLUDING DIMINISHING SNOW IN EASTERN COUNTIES. .MQT...NONE. JS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 844 PM CST FRI DEC 24 1999 FORECAST IN PRETTY GOOD SHAPE THIS EVENING. LOW CLOUDINESS COVERING ALL BUT THE FAR WESTERN AND EASTERN EXTREMES OF THE CWA WITH CEILINGS AND VISIBILITIES CONTINUING TO FALL. LATEST RUC AND 18Z ETA BOTH AGREE THAT THE LOW CLOUDINESS WILL BE MOVING OUT OF MN BY DAYBREAK. THIS IS BASED ON THE WARM FRONT OVER THE EASTERN DAKOTAS MOVING INTO EASTERN MN BY DAYBREAK. LAMP ANALYSIS SHOWS THAT THE FRONT IS HARDLY MOVING PROBABLY DUE TO THE COLD TEMPERATURES...SNOW COVER AND HIGH PRESSURE RIDGING ACROSS THE WESTERN GREAT LAKES. LOOKING AT THE BIG PICTURE WITH THE FOG PRODUCT INDICATES THAT A SLOW CONTRACTION TO THE LOW CLOUDS IS OCCURRING WITH EAST CENTRAL MN BEING IN THE MIDDLE. WILL CHANGE THE WORDING A LITTLE FOR WESTERN MN AND INDICATE CLEARING DURING THE EARLY MORNING HOURS. WILL KEEP PARTIAL CLEARING FOR LATE TONIGHT IN EASTERN MN. NO CHANGES TO WEST CENTRAL WI. WILL KEEP THE MENTION OF PATCHY FREEZING DRIZZLE WITH VISIBILITIES DROPPING TO A COUPLE OF MILES IN THE FOG. TEMPERATURES WILL BE SLOWLY RISING IN THE WEST AND NEARLY STEADY IN THE EASTERN CWA. JUST A LITTLE REWORDING HERE. CHRISTMAS DAY LOOKS QUITE PLEASANT WITH SUNSHINE AND WARMER TEMPERATURES. 00Z UPPER AIR CONFIRMS H8 +12C WARM POCKET IN THE WESTERN DAKOTAS. THERMAL RIDGE WILL BE OVER SOUTHERN MN AND WI MIDDAY SATURDAY. WILL INDICATE A LITTLE MORE SUNSHINE FOR EASTERN MN. WITH MODERATE W TO NW SURFACE WINDS...HIGHS SHOULD GET WELL INTO THE 40S IN WESTERN MN AND INTO THE LOWER 40S EASTERN MN/WI. .MSP...NONE. HILTBRAND mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 850 PM EST FRI DEC 24 1999 LTST SFC ANALYSIS SHOW FIRST TROF XTNDG FM CHS W THROUGH AMG AND MOVG SE. CD AIR TRAILING THE TROF JST A BIT...XTNDG FM FLO SW TO ABY AND ALSO MOVG TO THE SE. AS WIND DIR BECOMES MORE NRLY...TEMPS WL FALL AND WNDS TO PICK UP. PRIMARY VORT HDNG TWD NC CST ATTM...AND TAKING CLDS WI IT...WI ONLY CLDS ACRS CWA NOW ALNG SC CST. WK SCNDRY S/WV OVR WRN TN WL SWING THRU SE GA OVRNGT...BUT ATMOS SO DRY THAT HARD EVEN TO PRODUCE SCT CLDS. TOO BAD...WUD LIKE TO HAV SEEN JST ENUF MSTR TO SQUEEZE OUT A FEW FLURRIES FOR XMAS...BUT JST NOT THERE. WL GO WI EITHER MSTLY CLR OR CLEARNG ACRS ENTIRE CWA. WL UP WINDS INLAND TO 15 TO 20 MPH AS RUC ANALYSIS SHOWS H925 WNDS 20 TO 25 KTS AND PROGGED TO STAY NR THERE ALL NGT WI VRY STG CAA. TEMPS...WHILE STG CAA COMES IN OVRNGT...MAY BE TUFF TO GET MUCH COLDER THAN 30 ALNG CSTL COUNTIES WI WNDS STAYING UP ALL NGT. WL ADJST TEMPS UP JST A LTL ON CST AND ALSO UP THEM A NOTCH INLAND AREAS PER SAME REASNG. CWF...THINGS GOING PRETTY MUCH ACCORDING TO SCHEDULE THIS XMAS EVE. CD FNT IS CURRENTLY MOVG INTO THE SC WATERS AND WL MOVE INTO THE GA WATERS IN A FEW HRS. CURRENT FCST LOOKING FINE. ONLY CHG THIS PKG WL BE TO INCLUDE THE CHS HARBOR IN THE SCA AS WINDS SHUD INCREASE TO 20 KT W/I 12 HRS. ALL ELSE LOOKS FINE. .CHS... SC...SMALL CRAFT ADVISORY SOUTH SANTEE RIVER TO SAVANNAH OUT 20 NM. GA...SMALL CRAFT ADVISORY SAVANNAH TO ALTAMAHA SOUND OUT 60 NM. WOODWORTH/TJR sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1015 AM EST FRI DEC 24 1999 STRANGELY ENOUGH...THE FORECAST SEEMS TO BE WORKING OUT ALMOST THE WAY I THOUGHT IT WOULD YESTERDAY. LIGHT SNOW THAT DEVELOPED IN THE WEAK Q CONVERGENCE/WARM ADVECTION OVER EASTERN TN AHEAD OF THE SHORT WAVE DIVING SE OVER THE LOWER OH VALLEY IS NOW RUNNING UP THE WESTERN SLOPE OF THE APPALACHIANS. SEVERAL LOCATIONS IN THE MOUNTAINS HAVE REPORTED LITE SNOW THIS MORNING. THE CURRENT SET OF ZONES REALLY SEEMS TO HAVE A GOOD HANDLE ON THE SITUATION. EXPECT THIS INITIAL BIT OF PRECIP ASSOCIATED WITH THE SHORT WAVE TO DIMINISH AS IT CROSSES THE MOUNTAINS THIS AFTERNOON...WITH MORE LINGERING UPSLOPE SNOW OVER THE NRN MOUNTAINS INTO THE EVENING. DO NOT SEE ANY INDICATIONS IN THE 06Z ETA/12Z RUC/OBSERVATIONS THAT WE NEED TO STEP UP TO A WARNING AT THIS POINT...THUS WILL KEEP THE ADVISORY UNCHANGED. THE ONLY MINOR PROBLEM WITH THE FORECAST IS WHAT TO DO EAST OF THE MOUNTAINS...ESPECIALLY OVER UPSTATE SC. THE CLOUDS HAVE NOT ARRIVED EARLY ENUF TO HELP KEEP THE TEMPS DOWN. WILL PROBABLY HAVE TO BUMP HIGHS UP A FEW DEGREES...WHICH WILL MESH BETTER WITH CAE ZONES ANYWAY. ONE INTERESTING ITEM IN THE 06Z ETA IS A BLOB OF LOW LEVEL RH THAT THE MODEL BRINGS ACROSS THE FRENCH BROAD VALLEY AND OUT TO THE ESE ACROSS THE NORTHERN PART OF UPSTATE SC BETWEEN 21Z AND 00Z...WHICH SUGGESTS THE POSSIBILITY OF A FEW SNOW SHOWERS LATE IN THE AFTERNOON. HOWEVER...WILL CONTINUE TO AVOID THE CHRISTMAS EVE WISH-CAST AND KEEP THE FEW FLURRIES WORDING FOR NOW. .GSP...WINTER WEATHER ADVISORY TODAY FOR THE NORTHERN NC MOUNTAINS... NCZ033-048>050. MOORE sc AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 935 AM CST FRI DEC 24 1999 UPDATED ZONES TO REMOVE CLOUDS FROM ABR AREA ZONE...AS LOW CLOUD BAND HAS SHIFTED EAST SOMEWHAT. EASTERN COUNTIES WILL BE STUBBORN TO CLEAR...LATEST RUC T-SECT FOR ATY AREA SHOWS 80-90 PERCENT RH FROM SFC TO NEARLY 850 MB AND A LAYER OF WARMER AIR PERSISTING SLIGHTLY HIGHER. RUC ALSO SHOWS THIS MOISTURE LAYER BECOMING MORE SHALLOW WITH TIME...SO KEPT IN MENTION OF DECREASING CLOUDS THIS AFTERNOON. A FEW CALLS THIS MORNING INDICATED SOME PTCHY -ZL AREAS TO EAST OF ABR...AND HAVE ISSUED A SPS TO COVER...DOESN'T SEEM WIDESPREAD ENOUGH TO MERIT ADVISORY. AS FAR AS TEMPS GO...FEEL NW COUNTIES...MBG AREA...HAS GOOD CHANCE TO BREAK RCD HIGH OF 46 TODAY. RUC 850 MB TEMP REACHES 8C BY 20Z TODAY...WITH MIXING AND PLENTY OF SUN...SHOULD TO MIX LOWER LEVELS NICELY. SW COUNTIES...PIR AREA...ALSO HAS A SOMEWHAT LESSER CHANCE OF BREAKING RCD HIGH...SO WILL WATCH CLOSELY. RCDS OVER E HALF OF AREA LOOK SAFE...ESPECIALLY FAR EAST W/CLDS HANGING IN. .ABR...NONE. LORENS sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MEMPHIS TN 720 AM CST FRI DEC 24 1999 COLD FRONT PUSHING INTO NRN PORTIONS OF THE CWA THIS MORNING. LATEST 11-3.9 MICRON IMAGERY SHOWS 30-50KFT CLOUD DECK DROPPING SOUTHWARD AND WILL LIKELY THROW A FLY IN THE "MSUNNY" FCST FOR A WHILE TODAY. LATEST RUC REMAINS VIGILENT IN PUSHING MSTR QUICKLY EAST BY MIDDAY AND ALLOWING FOR PLENTY OF SUNSHINE THIS AFTN. WILL ISSUE QUICK UPDATE TO ADJUST FOR CURRENT CONDITIONS AND WIND SHIFT. .MEM...NONE. CBD tn DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 1000 AM CST FRI DEC 24 1999 SHORT TERM...ETA AND RUC GUIDANCE BOTH INDICATE HIGH MOISTURE VALUES PERSISTING OVER THE CWA DESPITE SOME INDICATIONS OF CLD EROSION ON VSBL IMAGERY. THE 12Z BRO SOUNDING SHOWS A WEAKER BUT STILL PERSISTENT LOW LEVEL INVERSION PRESENT BELOW 800 MB. LOW LEVEL WINDS REMAIN FROM THE NORTH AROUND THE CWA AND THIS WILL MAINTAIN BKN TO OVC CONDITIONS THROUGH THE DAY. AFTER YESTERDAYS HIGH OF 65 DEG HERE AT BRO...FORECAST HIGHS OF THE LOWER TO MIDDLE 60S LOOK GOOD AND IS CLOSE TO FWC NUMBERS. ISOLD TO WIDELY SCT SHOWER ACTIVITY CONTINUES TO MOVE NE OUT OF MEXICO TOWARDS THE CWA. THIS MATCHES WELL WITH WHERE THE ETA GUIDANCE SHOWS THE MAX 700MB LIFT ALONG NORTHERN MEXICO/TEXAS BORDERE REGION. 20 % POPS SHOULD COVER THIS. SO ALL IN ALL...NO CHANGES NEEDED TO CURRENT ZFP. MARINE...BUOY020 REMAINS AROUND 5 FT AT 5 SEC WITH A N WIND AROUND 10 KT. THIS HAS BEEN ON A SLOW DOWNWARD TREND OVER THE LAST SEVERAL HOURS AND CONDITIONS WILL REMAIN BELOW SCA CRIT. KBRO RADAR SHOWS ISOLD TO WIDELY SHOWERS MOVING OFFSHORE FORM THE INLAND AREAS. ALL OF THESE CONDITIONS ARE HANDLED WELL IN THE CURRENT CWF...NO CHANGES NEEDED ATTM. WILL ALSO CONTINUE TO MENTION SCEC IN THE 1ST PD. SYN/MESO...60/HMT...CAMPBELL .BRO...NONE. tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 920 PM EST FRI DEC 24 1999 TYPICAL WINTER PROBLEM...CLEARING STOPS AT OHIO RIVER THIS EVENING. MESOETA AND THE RUC PICK UP ON THIS NICELY AND HOLD CLDS IN OVR THE REGION FOR MOST OF THE NITE. HWEVR...WILL STILL GO WITH CLEARING AFT MIDNITE IN THE WEST AS LOW LEVEL CD ADVTN CEASES AND CLEARING IS CLOSE BY...BUT WILL KEEP CLDS IN OVR THE MTNS TNITE AND SNW SHWRS ENDING AFT MIDNITE. ALTHO VSBY BRIEFLY LWR IN HVR SNW SHWRS...EXPECT LITTLE SNW ACCUM. AS A RESULT TMPS WILL BE ADJUSTED UP TO ACCOUNT FOR CLDS. NO CHGS BEYOND TNITE. .RLX... WV...NONE. VA...NONE. KY...NONE. OH...NONE. .END/JMV wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 900 PM CST FRI DEC 24 1999 PRIMARY FORECAST CONCERNS...FREEZING DRIZZLE CHANCES AND TEMPERATURES. 02Z SURFACE ANALYSIS SHOWED WARM FRONT STRETCHING ACROSS EASTERN DAKOTAS INTO EASTERN NEBRASKA. LARGE AREA OF LOW CLOUDS PRECEDE THE FRONT AND WERE DEPICTED BY 925 MB RELATIVE HUMIDITY IN LATEST RUC AND ETA. THESE CLOUDS ARE ANTICIPATED TO SPREAD OVER PRETTY MUCH ALL OF THE FORECAST AREA DURING THE NIGHT. SURFACE REPORTS INDICATED CEILINGS/ VISIBILITY LOWERING ACROSS SOUTHERN MN AND NORTHERN IOWA AS ATMOSPHERE SATURATES...WHICH HAS BEEN SHOWN WELL BY TIME/HEIGHT CROSS SECTIONS. POSSIBILITY OF FREEZING DRIZZLE OVERNIGHT AND INTO MORNING HOURS OF CHRISTMAS DAY LOOKS GOOD. THIS BASED ON CLASSIC FREEZING DRIZZLE SOUNDING WITH SATURATED LOWER LAYER AND POTENTIAL FOR COLLISION- COALESCENCE PROCESS...TOPPED BY DEEP DRY LAYER ABOVE. AS NOTED BY PREVIOUS ARX FORECASTER...STRONG WARM AIR ADVECTION IN FULL SWING...WHICH WILL CAUSE TEMPERATURES TO RISE DURING THE NIGHT. FORECAST SOUNDINGS SUGGEST READINGS REACHING UPPER TEENS TO LOWER 20S BY MORNING. CURRENT FORECAST HANDLES OVERALL SCENARIO QUITE WELL TONIGHT...SO UPDATE NEEDED ONLY TO ADJUST WORDING AND WILL BE ISSUED AROUND 930 P.M. .LSE...NONE. THOMPSON wi WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 300 AM MST SAT DEC 25 1999 HIGH PRESSURE ALOFT OVER THE FORECAST AREA WEAKENING AS EXTREME NORTHERN MEXICO UPPER LOW RETROGRADES NORTHWEST. CLOUD MASS OVER THE SOUTHERN HALF OF NEW MEXICO MOVING NORTHWARD.. EXTRAPOLATION AND RUC MODEL SHOWS THAT THE NORTHERN EDGE OF CLOUD MASS WILL REACH THE SOUTHERN ZONES BY AFTERNOON. MODELS MOVE UPPER LOW INTO CENTRAL ARIZONA BY SUNDAY AFTERNOON.. BUT A VORTICITY LOBE DOES ROTATE ACROSS THE SOUTHERN ZONES. ETA/AVN MODEL SUGGEST LIGHT PRECIPITATION APPROACHING THE SOUTHERN ZONES LATER TONIGHT.. BUT CURRENT OBSERVATIONS INDICATE THAT THE DEEPER MOISTURE IS CONFINED TO THE CENTER OF UPPER LOW. THEREFORE EXPECT AN INCREASE OF ALTOCUMULUS SOUTHERN ZONES LATER TODAY OTHERWISE NO INDICATION OF ANY PRECIPITATION THREAT THROUGH SUNDAY. MILD CONDITIONS WILL PREVAIL ACROSS MOST OF THE FORECAST AREA TODAY. SOME SENSORS IN THE HIGH COUNTRY SHOWED TEMPERATURES IN THE 40S. WITH 700 MB TEMPERATURES STAYING AROUND 0C FOR ANOTHER DAY.. EXPECT ANOTHER MILD DAY. BUT THE SNOW COVERED YAMPA RIVER BASIN CONTINUES TO BE COLD UNDERNEATH STRONG INVERSIONS.. THE ONLY PORTION OF THE FORECAST AREA NOT JOINING IN THE DECEMBER MILD WEATHER PATTERN. DOES NOT APPEAR THE COLD ADVECTION ALOFT ON SUNDAY WILL WEAKEN INVERSIONS ENOUGH TO ALLOW SOME MIXING AND WARMING.. WILL GO ALONG WITH TEMPERATURE PERSISTENCE THOSE ZONES WITH PATCHY NIGHTTIME AND MORNING FOG. FRISBIE .GJT...NONE. WESTERN COLORADO AND EASTERN UTAH EMERGENCY MANAGERS SHOULD MAINTAIN A NORMAL LEVEL OF WEATHER AWARENESS TODAY. co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KEY WEST FL 258 AM EST SAT DEC 25 1999 OVER THE FLORIDA KEYS THIS HOLIDAY MORNING...SKIES ARE CLEAR WITH NORTH WINDS OF 15 TO 20 KNOTS USHERING IN SURFACE DEWPOINTS IN THE MID TO UPPER 40S. TEMPERATURES ARE FALLING THROUGH THE 60S...64 DEGREES AT LAST CHECK HERE IN KEY WEST...WITH A FORECAST MINIMUM TEMPERATURE NEAR 60 FOR KEY WEST AND THE UPPER 50S FOR THE UPPER KEYS LOOKING RIGHT ON TRACK. AT 2AM MIAMI REPORTED 55, WHILE HOMESTEAD REPORTED 50 DEGREES. SATELLITE IMAGERY REVEALS STRATOCUMULUS CLOUDS SLIDING SOUTHWARD ALONG THE WEST CENTRAL COAST OF FLORIDA IN THIS COLD ADVECTION PATTERN. THE NEARSHORE EDGE OF THIS BANK OF CLOUDS IS NEARING THE LATITUDE OF FORT MYERS AS OF THIS WRITING WITH A FURTHER SOUTHWARD INTRUSION VISIBLE FARTHER OFFSHORE. OF CONCERN TO FLORIDA KEYS RESIDENTS WILL BE THE TIMING AND IMPACT OF THIS STRATOCUMULUS ON OUR COASTAL WATERS AND KEYS SKY COVER. THE TREND IN OUR THOUGHTS ON THE ARRIVAL OF THIS STRATOCUMULUS DECK IS TO BRING IT IN SOONER RATHER THAN LATER...SLIGHTLY BEFORE NOONTIME CHRISTMAS DAY. THE RUC MODEL DEPICTS THE MOVEMENT OF THIS PATCH OF STRATOCUMULUS RATHER WELL. WITH THE FORECAST WIND TRAJECTORIES REMAINING NEARLY DUE NORTH, I EXPECT ONLY THE COASTAL WATERS WEST OF THE MARQUESAS KEYS TO BE IMPACTED BY THESE NUISANCE CLOUDS. SATELLITE IMAGERY WILL BE MONITORED RIGHT UP UNTIL ISSUANCE TIME TO ARRIVE AT THE BEST FORECAST TIMING AND LOCATION. ASIDE FROM THE CONCERNS OF CLOUDS ENTERING OUR FORECAST AREA...THE SURFACE WINDS OVER THE KEYS WILL REMAIN NORTHERLY AT OR JUST OVER 20 KNOTS THROUGH MOST OF THE NEXT 48 HOURS WHICH WILL REQUIRE SMALL CRAFT ADVISORIES TO REMAIN IN EFFECT FOR CHRISTMAS, CHRISTMAS NIGHT, AND PERHAPS A PERIOD OR TWO BEYOND THAT. REASON BEING THAT ANOTHER SHORTWAVE IS SWINGING AROUND THE BASE OF THE EASTERN UNITED STATES TROUGH...PRESENTLY IN THE JACKSONVILLE VICINITY...WHICH WILL KEEP OUR GRADIENT AT LEAST AS TIGHT AS IT IS AT THIS POINT. THE NUMERICAL MODELS ALSO ADVERTISE AT LEAST ONE MORE SHORTWAVE ROUNDING THE TROUGH BEFORE IT BEGINS TO LIFT OUT NEXT WEEK. OF MINOR CONCERN THIS CHRISTMAS MORNING WILL BE THE COOL APPARENT TEMPERATURES TO BE EXPERIENCED WHEN THE MODERATE NORTHERLY WINDS ARE FACTORED IN WITH OUR TEMPERATURES NEAR 60. WIND CHILLS...IF YOU CAN CALL THEM THAT BY NORTHERN STANDARDS...WILL BOTTOM OUT IN THE UPPER 40S EARLY THIS MORNING...WHICH MAY CHILL THOSE NOT ACCUSTOMED TO SUCH NON-TROPICAL CONDITIONS. GUIDANCE LOOKS RATHER ACCEPTABLE AS FORECASTS FOR THIS SITUATION. EYW UV 067/058 069/058 070 320000 .EYW...SMALL CRAFT ADVISORY FOR ATLANTIC WATERS FROM OCEAN REEF TO 20 NM WEST OF DRY TORTUGAS OUT 60 NM INTO THE STRAITS... FLORIDA BAY...AND GULF SIDE OF THE LOWER KEYS OUT 20 NM... AND GULF WATERS FROM 20 TO 60 NM WEST OF CHOKOLOSKEE TO 20 NM WEST OF DRY TORTUGAS. SETTELMAIER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1015 AM EST SAT DEC 25 1999 COOP REPORTS THIS MORNING INDICATE THAT A WHITE XMAS WAS HAD BY RESIDENTS IN THE NORTHERN ADIRONDACKS...THE WESTERN SLOPES OF THE GREEN MTNS...THE NORTHEAST KINGDOM...MUCH OF CENTRAL VT...AND THE HIR TRRN OF SRN VT. XMAS WAS BROWN FOR 2 YEARS IN A ROW HERE AT BTV...WHICH IS PRETTY RARE FOR THESE PARTS. AT LEAST THE TEMPS OUTSIDE FEEL LIKE WINTER FOR A CHANGE. HI PRESS RIDGE TO MOVE SE ACRS THE FA TDY...AS A STORM SYS TRACKS ACRS SOUTHERN HUDSON BAY. THIS SYSTEM/S ASSOCIATED COLD FRONT WILL BE DROPPING DOWN ACRS THE GREAT LKS REGION OVRNITE TONITE. H5 UPR RIDGE NOT FORECAST TO MOVE THROUGH THE FA UNTIL AROUND 06Z TONITE WITH A STRONG VORT MAX DIVING DOWN ACRS THE GREAT LKS REGION OVRNITE TONITE. SOUTHWESTERLY GRADIENT TO INCREASE INTO TONITE. BUFKIT INDICATES LES POSSIBLE ACRS ST LAW VLY FROM 20-23Z TIME FRAME IN SW FLOW...BUT WITH TEMPS WARMING ALOFT AND NOT MUCH GOING ON ATTM ALONG LK ONT WILL HOLD OFF ON MENTIONING ANY SN AND JUST HANDLE ANY PCPN THAT MAY DEVELOP INTO THE EARLY EVENING HOURS WITH THE STF. ANY PCPN THAT WILL OCCUR SHOULD BE VRY LT ANYWAYS (FLURRIES). NGM SHOWS H85 WAA ACRS THE FA THRU THE TONITE PERIOD (ALTHOUGH IT IS WK TO START OUT WITH). IR SAT PIX SHOW CLDS DROPPING DOWN ACRS ONT AND WESTERN QUE ATTM. TRACKING THESE CLDS HAS THE LEADING EDGE REACHING THE ST LAW VLY BY AROUND 21Z (AROUND SUNSET)...THEN ACRS THE NORTHERN ADIRONDACKS AND INTO THE NORTHERN CHAMP VLY BY AROUND 23Z. MODELS SHOW A LIL BIT OF DEEPER MOISTURE DROPPING DOWN FROM EASTERN CANADA AFT 18Z TDY...BUT FEEL WITH UPR RIDGE STILL IN PLACE AND LEADING EDGE OF CLDS ERODING IN THE IR SAT PIX THAT THE CLDS WON/T MAKE MUCH PROGRESS INTO THE FA UNTIL THE EVENING HOURS. HAVE INCLUDED MORE SUN FOR TDY IN THE ZFP BECAUSE OF THIS. 12Z RUC HAS MAX TEMPS IN THE SINGLE DIGITS IN NE VT AND THE ADIRONDACKS...WITH TEENS ELSEWHERE. MAY HAVE TO BUMPS TEMPS DOWN A LIL IN THE ST LAW VLY AND IN THE MTNS FOR TDY. PRELIM WORK ZONES GONE. FINAL ISSUANCE AFTER LOOKING AT LATEST LAMP DATA. MERRY CHRISTMAS TO ALL! .BTV...NONE. MURRAY vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1030 AM EST SAT DEC 25 1999 UPDATE CONCERNS ARE WITH CLOUDS EARLY AND TIMING OF HIGH WINDS LATE. WATER VAPOR LOOP SHOWS A POTENT SHORTWAVE NORTH OF MINNESOTA... HAVING RACED ACROSS CANADA OVERNIGHT. SURFACE ANALYSIS/METARS SHOW BROAD LOW PRESSURE LOCATED OVER HUDSON BAY...WITH A SURFACE WAVE OVER NORTHERN ONTARIO ASSOCIATED WITH THE UPPER SHORTWAVE. ASSOCIATED WITH WAVE...A WARM FRONT EXTENDED NORTH-SOUTH ACROSS MINNESOTA AND A COLD FRONT EXTENDED EAST-WEST ACROSS THE NORTH END OF LAKE WINNIPEG. 12Z RAOBS SHOWED A 150KT 300MB JET PUSHING THE SHORTWAVE ALONG. CLOSER TO THE GROUND...CYQD SOUNDING SHOWED A 75KT 850MB JET AT 12Z...AND SURFACE WINDS 42G56KT AT 14Z. CLOSER TO HOME...KINL SOUNDING SHOWED 50KT+ WINDS ABOVE 850MB..BUT WITH A STRONG INVERSION PREVENTING THE WINDS FROM MIXING TO THE SURFACE. LOW CLOUDS COVER MUCH THE FORECAST AREA...AHEAD OF THE WARM FRONT OVER MINNESOTA. A RATHER LARGE BREAK HAS DEVELOPED OVER WEST CENTRAL UPPER MICHIGAN...WHICH SEEMS TO ALIGN WITH THE 12Z RUC 925MB RH FIELD. THIS BREAK WILL CONTINUE TO WIDEN DURING THE DAY...AS MOST OF THE MOISTURE ASSOCIATED WITH THE WARM FRONT STAYS SOUTH OF THE FORECAST AREA. SOME CLOUDS SHOULD REMAIN OVER THE TIP OF THE KEWEENAW...AS THE SOUTHWEST TRAJECTORIES WILL PICK UP MOISTURE FROM LAKE SUPERIOR. TEMPERATURES DROP RAPIDLY BEHIND THE COLD FRONT. AT CYKJ IN NORTHERN ALBERTA...THE SURFACE TEMPERATURE DROPPED 31 DEGREES F IN 6 HOURS /FROM 41F AT 08Z TO 10F AT 14Z/. THE CAA WILL QUICKLY WIPE OUT THE INVERSION AND ALLOW WINDS FROM AT LEAST 850MB TO MIX DOWN TO THE SURFACE...AND POSSIBLY FROM 800-750MB DURING THE INITIAL COLD PUNCH. 12Z RUC HAS A GOOD HANDLE ON THE 850MB WINDS AND COLD ADVECTION/ INCREASED MIXING OVER CENTRAL CANADA. A QUICK LOOK AT THE 12Z ETA AGREES. BASED ON ARRIVAL OF COLD AIR AND DECENT MIXING AS SHOWN BY 1000-850MB LAPSE RATES >10C/KM AND ETA FORECAST SOUNDINGS...THE KEWEENAW PENINSULA MAY REACH WARNING CRITERIA BY THIS EVENING. WILL ISSUE A HIGH WIND WARNING NOW...TO PROVIDE MORE LEAD TIME. WILL ISSUE WARNINGS FOR LAKE SUPERIOR COUNTIES TO THE EAST ALSO...RATHER THAN WAIT UNTIL THE NEXT NPW. ADVISORY FOR INTERIOR COUNTIES WHERE MIXING IS MORE DIFFICULT. COORD WITH APX...DLH...GRB. .MQT...HIGH WIND WARNING THIS EVENING MIZ001>003-009 HIGH WIND WARNING TONIGHT MIZ004>007-014 HIGH WIND ADVISORY TONIGHT MIZ010-013 STORM WARNING TONIGHT AND SUNDAY LAKE SUPERIOR JHB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1150 AM CST SAT DEC 25 1999 UPDATED THE ZONES TO REFLECT TEMPS/WINDS AND STRONGER WINDS TON. QUITE A DIFFERENCE IN TEMPERATURES ACROSS THE FORECAST AREA...WITH LITTLE SIOUX IOWA JUST MAKING IT TO 30 DEGREES...HERE AT THE STATION IN VALLEY WE ARE 46 DEGREES...AND TEMPS WERE CLOSE TO 50S IN THE FAR WRN ZONES. SNOWCOVER LINGERS ESPECIALLY IN THE FAR ERN NEB ZONES AND WRN IA. THE WNDS WILL BE SLOWEST TO COME UP IN THESE AREAS...THUS WARMEST TEMPS FORECAST IN THE WESTERN ZONES. THIS AM/S SOUNDING AND THE FCST SOUNDINGS SHOW THAT WE WILL NOT SEE THE FULL POTENTIAL OF THE WRM TEMPS ALOFT. THE 850MB ANALYSIS HAD THE +12 DEG C AIR FM LBF N TO SD AND ND...WITH THE THERMAL RIDGE SLIPPING TO SE NEB BY 00Z BY ALL THREE MODELS. THE RUC APPEARS TO MOVE THE WRM AIR OFF TOO QUICKLY IN THE SHORT TERM. THE QUESTION TONIGHT WILL BE THE WNDS...850MB WINDS TO INCREASE TO AROUND 50KTS BY SUN AM. THE NGM WNDS APPEAR OVERDONE...HOWEVER...HAVE ADJUSTED THE TON WND FCST TO REFLECTS SOME GUSTS AS A SURGE OF COLDER AIR CLIPS THE FCST AREA. MODELS DIFFER ON THE MOISTURE AVAILABLE/TIMING FOR -SN LATE SUN AND MON AND WILL ADDRESS IN THE AFT AFD. .OMA...NONE ZAPOTOCNY ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBUQUERQUE NM 1040 AM MST SAT DEC 25 1999 WILL SHIFT HIGHLIGHTS FARTHER TO THE NORTHWEST BASED ON LATEST RUC2 OUTPUT AND TRENDS FROM SATELLITE AND RADAR IMAGERY. THINK THE WORST IS OVER IN SOUTHCENTRAL MOUNTAINS SO WILL DOWNGRADE WINTER STORM WARNING TO AN ADVISORY IN ZONES 16 AND 17. AS FOR HIGHLIGHTS BEYOND THIS AFTERNOON...WILL ADDRESS THAT POSSIBILITY IN THE AFTERNOON PACKAGE. 38 .ABQ...SNOW ADVISORY NMZ002-004-005-008-010-011-014-016-017 THIS AFTERNOON... nm