AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE KEY WEST FL 830 PM EST SAT JAN 8 2000 GRADIENT HAS WEAKENED SOME DURING THE PAST 24 HOURS WITH SURFACE HIGH MOVING THRU NC. SLIGHTLY DRIER AIR HAS ALSO MOVED IN WITH DEWPOINTS DOWN IN THE UPPER 60S. SCATTERED TO BROKEN CUMULUS CLOUDS FOUND OVER THE FLORIDA STRAITS THIS EVENING...BUT THE ISLAND CHAIN IS MOSTLY CLEAR AS THE CLOUDS HAVE BEEN DISSIPATING BEFORE MOVING ONSHORE. ISOLATED SHOWERS ARE WEST OF ANDROS ISLAND. THIS EVENING SOUNDINGS ARE QUITE DRY AT BOTH KBYX AND KMFL WITH PRECIPITABLE WATER DOWN TO NEAR .85 INCHES. EASTERLY FLOW DOES EXTEND TO NEAR 700 MBS AT BOTH SITES...BUT IT IS ONLY AT 5 TO 10 KNOTS. WHAT LITTLE MOISTURE THERE IS IS CONFINED TO THE LOWER LEVELS. BOTH SITES ARE QUITE STABLE WITH K-INDICES BELOW ZERO AND LIFTED INDICES ABOVE ZERO. SOUNDINGS LIKE THIS SUPPORT LITTLE IN THE WAY OF SHOWERS. THE PAST SEVERAL NIGHTS HAVE SEEN SURFACE WINDS BACK TO MORE NORTHEAST OR EVEN NORTH-NORTHEAST OVERNIGHT AS GRADIENT RELAXES. WITH AN EVEN WEAKER GRADIENT TONIGHT AND SOME NORTHEAST COMPONENT TO LOW LEVEL WIND IT MAY HAPPEN AGAIN TONIGHT. WITH LOWER DEWPOINTS AND BACKING TO WIND TEMPS WILL BE A TAD LOWER THAN LAST NIGHT. WILL WATCH TEMP FALL THIS EVENING TO SEE IF I WILL LOWER TEMPS TONIGHT. WILL ALSO MAKE COSMETIC CHANGES TO WORDING OF SKY COVER FORECAST. EXCEPT FOR DRYF1 WHICH HAS BEEN 10 TO 13 KNOTS THIS EVENING ALL OTHER SITES MOSTLY 10 KNOTS OR LESS. RUC AND ETA DOING THE BEST ON THE WIND FORECAST AND THEY SHOW ONLY 10 KNOTS ALL NIGHT. BOUNDARY LAYER WIND ON EVENING SOUNDING NORTHEAST TO EAST AT 5 TO 10 KNOTS. WILL LOWER WIND TO 10 KNOTS TONIGHT IN CWF BASED ON ABOVE REASONING. .EYW...NONE. MOHLIN fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1050 PM EST SAT JAN 8 2000 03Z SFC ANALYSIS SHOWS HIGH PRESSURE OVER THE EASTERN SEABOARD. THERE IS A WEAK SFC REFLECTION OF A LOW IN LOUISIANA WHERE MIDLEVEL MOISTURE CONTINUES TO STREAM NORTHEAST WARD AROUND THE HIGH. THE LATEST MESOETA AND RUC SUPPORT KEEPING MOST OF THE NIGHT DRY WITH AN SHOWERS POSSIBLE TOWARD DAWN AS THE BETTER LIFT ARRIVES. UNDER THE CLOUDS TEMPERATURES WILL NOT DROP OFF MUCH SO LOWS AROUND 40 LOOK FINE. THE REST OF THE FORECAST IS ON TRACK...ESPECIALLY NOW THAT THE EARLIER SPRINKLES AND LIGHT RAIN HAVE MOVED OUT OF THE AREA. NO CHANGES AT THIS TIME. .JKL...NONE. GREIF ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 930 PM EST SAT JAN 8 2000 SYNOPSIS: A WEAK AREA OF LOW PRESSURE WILL QUICKLY MOVE ACROSS THE SOUTHERN PROVINCE OF QUEBEC AND WILL EXIT THE AREA BY MIDDAY SUNDAY. FOR NORTHERN MAINE...THE LOW WILL BRING A LITTLE BIT OF LIGHT SNOW INTO SUNDAY MORNING AND SLIGHTLY WARMER TEMPERATURES TO ALL OF THE STATE FOR SUNDAY AFTERNOON. A POTENTIALLY MUCH STRONGER LOW WILL LIKELY AFFECT THE REGION FROM LATE MONDAY INTO TUESDAY. THIS STORM MAY BRING SOME SIGNIFICANT SNOWS TO THE FAR WEST AND NORTH...AND RAINY AND WINDY CONDITIONS TO CENTRAL AND COASTAL AREAS. TECHNICAL DISCUSSION: GOING TO BACK OFF ON PRECIP POPS SOUTH OF GNR-HUL LINE FOR OVERNIGHT PERIOD. MAIN WWA BAND OF SN- HAS ENTERED STATE ON ROUGHLY ABOVE LINE AND WOULD EXPECT THE LINE TO PROGRESS SLOWLY NWD OVERNIGHT. LATEST FEW RUNS OF RUC AND 18Z RUN OF ETA SUPPORT THIS THINKING...AS THEY ONLY PRODUCE MEASURABLE PRECIP.../.05 - .15/...OVER ZONES 1 AND 2. NO CHNGS NEEDED TO MARINES THIS UPDATE. WINDS ALREADY FRESHENING OUT OF THE SW THIS EVE AND XPCT IT WILL REACH SMCR BY MIDNIGHT. OUTLOOK... NEW MED RNG GUIDANCE IN FROM 12Z NOGAPS AND ECMWF. BOTH ARE VERY CLOSE TO RECENT AVN SOLN W SCNDY FORMING ON NJ COAST AND MOVING RAPIDLY THRU BAY ON FUNDY AND NWD MON - TUE. THIS SCENRIO WOULD BRING A HEAVY WET SNOW TO NRN AND WRN SXNS OF ME WITH RAIN AND WIND CNTL AND COASTAL AREAS. ALTERNATIVELY...THE 12Z CANADIAN AND UKMET AGREE WITH SCDRY BUT ARE FURTHER WEST AND BRING MAINLY RAIN TO ENTIRE AREA. SO ITS 4 AGAINST 2 WHICH IS ALREADY POINTING IN FAVOR OF WINTER STORM WATCH FOR ZONES 1-4 MON NGT INTO TUE. MORNING SHIFT WILL HAVE BETTER LOOK WITH 00Z GUIDANCE. CCF: BGR EC 023/039 025/037 031 02231 232/343/00/05 CAR SC 012/030 013/033 024 02731 222/344/01/05 .CAR...SMALL CRAFT ADVISORY... COBB me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1055 PM EST SAT JAN 7 2000 FORECAST CONCERNS OVERNIGHT ARE CLOUD COVER...LOW TEMPS AND PROSPECTS FOR SIGNIFICANT. THIS EVENING...A WIND SHIFT BOUNDARY AND ASSOCIATED LOW CLOUDS WERE APPROACHING THE EASTERN UP FROM THE NORTHWEST...AND LOW CLOUDS WERE BRUSHING EXTREME SOUTHERN COUNTIES AS HIGHER DEWPOINTS PUSHED INTO THE REGION FROM THE SOUTHWEST. IN BETWEEN...SKIES WERE MAINLY CLEAR ACROSS MUCH OF THE FORECAST AREA. SURFACE BOUNDARY WILL PUSH INTO THE EASTERN UP LATER ON AND WILL LIKELY STALL AROUND THE STRAITS. SATELLITE IMAGERY AND 18Z MESOETA/0Z RUC LOW LEVEL MOISTURE PROGS SUGGEST THAT LOW CLOUDS WILL PUSH INTO THE EASTERN UP OVERNIGHT...ESPECIALLY INTO CHIPPEWA COUNTY. WILL UPDATE CHIPPEWA COUNTY SKY COVER TO MOSTLY CLOUDY...AND WILL CONTINUE PARTLY CLOUDY FORECAST FOR MACKINAC COUNTY. ACROSS THE SOUTH...LOW CLOUDS HAVE ONLY ADVANCED SLIGHTLY NORTH OF POSITION OF A COUPLE OF HOURS AGO. DO NOT EXPECT CLOUDS TO ADVANCE TOO MUCH FARTHER NORTH AS LOW LEVEL SHEAR AXIS WILL REMAIN IN PLACE AND LOW LEVEL ISENTROPIC LIFT WILL REMAIN CONFINED TO FAR SOUTH THROUGH 12Z. IN FACT...CLOUDS MAY ACTUALLY RETREAT LATER ON PER TEMPORARY DRYING AT 925 MB AS SHOWN BY 0Z ETA. THUS...WILL GO WITH VARIABLY CLOUDY (TO ALLOW FOR CLOUDY PERIODS) ACROSS THE FAR SOUTH-SOUTHEAST ALONG AND SOUTH OF A CAD-HTL-OSC LINE. FOR TH NEXT TIER OF COUNTIES FARTHER NORTH...WILL GO WITH PARTLY CLOUDY OVERNIGHT...AND WILL GO WITH MOSTLY CLEAR ACROSS NORTHERN COUNTIES OF NORTHERN LOWER MICHIGAN. ALSO...WILL NEED TO ADJUST SECOND PERIOD FORECASTS ACROSS THE SOUTH FROM CLOUDY TO BECOMING CLOUDY...TO ACCOUNT FOR FACT THAT THE DAY MAY ACTUALLY START WITH SOME SUNSHINE. WITH SURFACE WINDS DIMINISHING FURTHER OVERNIGHT...AND WITH THE COMBINATION OF LOW TEMPERATURE/DEWPOINT SPREADS AND SNOW COVER ACROSS MUCH OF THE AREA...WILL MENTION PATCHY FOG ALL COUNTIES OVERNIGHT. WILL MAKE MINOR TEMPERATURE ADJUSTMENTS...AND WILL FRESHEN WIND FORECASTS TO REMOVE EVENING REFERENCES. .APX...NONE. ROWLEY mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 953 PM EST SAT JAN 8 2000 TRANQUIL EVENING UNDERWAY ACROSS FA. FCST CONCERNS OVERNIGHT ARE TEMPS AND CLOUD COVER. LATEST SFC ANALYSIS SHOWS WEAK LOW PRESSURE SW OF JAMES BAY. WEAK TROF/WIND SHIFT PUSHING SE ACROSS LK SUPERIOR BARELY DISCERNIBLE NOW AS IT CONTINUES TO WASH OUT. 11-3.9 MICRON SAT IMAGERY SHOWS EXTENSIVE LOW CLOUD SHIELD ACROSS SW ONTARIO...EXTREME NE MN AND ALMOST ALL OF THE E 2/3RDS OF LK SUPERIOR INCLUDING KEWEENAW. EVENING SAT IMAGERY SHOWS LOW CLOUDS MAKING PROGRESS SE. SIMPLE EXTRAPOLATION BASED ON EVENING TRENDS SUGGESTS SCT TO OCCASIONALLY BKN CLOUDS WILL AFFECT AREAS NE OF A LINE FROM ONTONAGON TO MANISTIQUE. THIS GENERALLY IN LINE WITH 00Z RUC LOW-LEVEL RH FIELDS. 18Z ETA SHOWS SLIGHTLY LESS S PUSH OF CLOUDS. CURRENT ZONES HAVE A GOOD HANDLE ON CLOUD FCST AND WILL ONLY MAKE MINOR ADJUSTMENTS. WEAK PRESSURE GRADIENT ACROSS FA OVERNIGHT CONDUCIVE FOR CALM WIND AND IDEAL RADIATIONAL COOLING IN THOSE INTERIOR AREAS WHICH REMAIN CLR. GOOD SETUP FOR EXTREME RANGE OF TEMPS BETWEEN LOCAL COLD SPOTS AND LARGER TOWNS. CURRENT FCST HAS SITUATION GENERALLY IN HAND BY GOING 5-10 DEGREES BELOW GUIDANCE IN AREAS WITH LEAST CLOUD COVER. HOWEVER...WILL OPEN UP RANGE BY MOVING LOW END OF MINS DOWN ABOUT 5 DEGREES TO ACCOUNT FOR EXPECTED WIDE RANGE OF TEMPS UNDER CONDITIONS SETTING UP OVERNIGHT. WITH EXTENDED RADIATIONAL COOLING PERIOD...WILL CONTINUE MENTION OF PATCHY FOG AS MELTING OF SNOW TODAY HAS ADDED MOISTURE TO NEAR SFC LAYER. A CHECK OUTSIDE THE OFFICE REVEALS SOME SHALLOW FOG ALREADY BEGINNING TO FORM HERE. .MQT...NONE. ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1130 AM EST SAT JAN 8 2000 ONLY MINOR CHANGES PLANNED TO THE AFTERNOON FORECAST. WILL BE MORE OPTIMISTIC WITH WORDING THE SKY CONDITION AND INCREASE THE EXPECTED MAX TEMPS BY 2-4 DEG F FOR ALL ZONE GROUPINGS. WILL ALSO SLIGHTLY DECREASE WIND SPEEDS. LATEST SATL LOOPS SHOW SOME SCT/THIN CI/CS DEVELOPING OVER LAKE MI AND ERN WI...WITH MAIN CLOUD AREA TO THE SOUTH WITH LEADING EDGE OVER CENTRAL IL AND IN. LATEST RUN OF RUC II AND 12Z ETA KEEP THE GULF MOISTURE SOUTH OF THE FORECAST AREA THIS AFTERNOON...MOVING IT IN AFT 22Z. MID-LOW CLOUD DECK HAS ONLY ADVANCED AS FAR NORTH AS PEORIA IL AS OF 16Z...THUS AWIPS TIMING TOOL DOES NOT BRING THE LOW-MID CLOUDS INTO FORECAST AREA UNTIL AFTER SUNSET. THEREFORE... AFTERNOON FORECAST WILL BE MORE OPTIMISTIC AS FAR AS SKY CONDITION. TEMPS AT 16Z ALREADY AT OR SLIGHTLY ABOVE PREVIOUSLY FORECASTED MAX TEMPS. GOOD MIXING HAS MIXED DOWN THE SLIGHTLY WARMER AIR ALOFT. 12Z ETA FORECAST SOUNDINGS SHOW LITTLE ADDITIONAL WAA THIS AFTERNOON... THEREFORE EXPECT TEMPS TO RISE ONLY ANOTHER DEGREE OR TWO AT THE SFC THIS AFTERNOON. WIND SPEEDS GENERALLY IN THE 10 TO 20 KNOT RANGE THIS MORNING DESPITE THE 40-50 KNOT SPEEDS AT 3K FT. AS WINDS DECREASE ALOFT...DO NOT EXPECT SFC SPEEDS TO CHANGE MUCH FROM CURRENT VALUES. .GRR...NONE. GREENE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1040 AM EST SAT JAN 8 2000 12Z RAOBS SHOW SPLIT FLOW LINGERS ACRS NAMERICA. NRN GRT LKS UNDER INFLUENCE OF FAST ZONAL NRN BRANCH...WITH EMBEDDED SHRTWV/H3 90KT JET MAX IN SW ONTARIO THIS MRNG. ASSOCIATED 1002MB SFC LO OVR WRN ONTARIO WITH WARM FNT XNDG SWD TO NR KDLH AND INTO NCNTRL WI. TEMPS AHD OF THIS BNDRY FELL QUITE LO THIS MRNG WITH STNS THAT DECOUPLED OVR SN COVER (KIMT) RPRTG MINS CLOSE TO ZERO. LOCAL 12Z RAOBS SHOW STEEP SFC BASED RADIATION INVRN BLO WARM FNT INVRN. BUT WSWLY WNDS INCRS QUICKLY ABV SFC WITH APX SHOWING NR 50KTS AT 2K FEET IN SWLY FLOW BTWN ONTARIO LO AND HI PRES OVR CNTRL APPALACHIANS. WNDS DIMINISH UPSTREAM WITH WEAKER PRES GRADIENT AS INL RPRTG ONLY 30KT AT 2K FEET. IR SAT LOOP SHOWS FAST WLY FLOW ALF HAS MOVD COLDER CLD TOPS WELL DOWNWND OF WARM FNT...BUT SOME LO-MID CLD LINGERING FM KCMX-CYQT-MN ARROWHEAD. BUT 12Z RAOBS INDICATE ATMOSPHERE FAIRLY DRY WITH HIER RH ON INL SDNG AOB H7...SO NO PCPN RPRTD. MAIN FCST CONCERNS TDAY INCLUDE LINGERING CLDS AND FCST HI TEMPS. XPCT LINGERING MID CLD TO SPRD W TO E ACRS CWA TDAY WITH DRYING TREND AS RUC FCSTS DRY ADVCTN/QVECTOR DVGC IN H85-5 LYR. ALTHOUGH H85 TEMPS/LLVL STABILITY THIS MRNG TOO HI FOR LK CLD...LO CLD ACRS NW ZNS MAY BE A LTL HARDER TO CLR WITH COLD DENSE AIR OVR SN COVER AHD OF WARM FNT FAIRLY RESILIENT ESPECIALLY WITH WEAKENING PRES GRADIENT/WSWLY FLOW. ALTHOUGH WSWLY FLOW CLIMATOLOGICALLY FAVORS QUICK WARMUP...WL CONT GOING FCST TREND OF MAX TEMPS SLGTLY BLO MOS/LAMP GUIDANCE WITH LO LVL COLD AIR HANGING TOUGH PER FCST MESOETA BUFKIT FCST SDNGS. ONLY MINOR CHGS NECESSARY IN MRNG FCST. XPCT WNDS ON LK SUP TO REMAIN BLO GALE TDAY WITH HIER STABILITY AND PASSAGE OF WEAKER PRES GRADIENT. .MQT...NONE. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1006 AM CST SAT JAN 8 2000 A DRY WESTERLY FLOW COVERS THE REGION THIS MORNING AND THIS LOOKS TO BE THE CASE FOR THIS AFTERNOON AND TONIGHT. MORNING KMPX RAOB SHOWING 15 DEGS OF WARMING HAS OCCURRED IN THE PAST 24 HOURS AT 950 MB WITH A CURRENT TEMPERATURE OF +2C. NEARLY ISOTHERMAL CONDITIONS FROM 950 TO 850 MB. VISIBLE IMAGERY SHOWING A NICE SNOW FIELD ALONG AND SOUTH OF A LINE FROM THE SW TIP OF MN THROUGH THE TWIN CITIES TO RICE LAKE WI. STILL...TEMPERATURES IN THESE AREAS ALREADY NEAR 30 DEGREES. RUC AND 12Z ETA CONFIRM DRY CONDITIONS THIS AFTERNOON. WILL USE "SUNNY" FOR ALL AREAS. HIGH TEMPERATURE FORECAST LOOKS GOOD WITH LOWER 40S IN THE SOUTHWEST TO THE LOWER 30S IN THE NORTHERN WI CWA. .MSP...NONE. HILTBRAND mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 955 PM CST SAT JAN 8 2000 ADJUSTED TEMPS AND SKY CONDITIONS FOR MOST AREAS. FOG AND STRATUS SHULD KEEP TEMPS FAIRLY STEADY OVERNIGHT. QUICK PEEK AT RUC AND ETA SHOWS ISN LIFT TO CTN UNTIL AT LEAST MID DAY. ARRIVAL OF WESTERLY WINDS AND DRIER AIR WL BE LTL LATER ON SUNDAY. THUS...DONT XPCT CLDS TO BREAK UNTIL AFTN. WL WAIT TO TAKE A LOOK AT GUID TEMPS BEFORE MAKING ANY ADJUSTMENTS TO TEMPS ON SUNDAY. .EAX... KS...NONE. MO...NONE. SF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 248 PM CST SAT JAN 8 2000 THE MAIN FORECAST CHALLENGE IS THE HANDLING OF A SERIES OF FAST MOVING SHORT WAVES DROPPING INTO THE MEAN UPPER TROUGH OVER THE CENTRAL U.S. ASIDE FROM THE TYPICAL CONCERN OF TEMPS AND CLOUD COVER...A CONVECTIVE PCPN EVENT IS A DISTINCT POSSIBLITY SUNDAY AFTN. IN THE SHORT TERM...LOW CLOUDS FROM THE SOUTH WILL LIKELY AFFECT RICHARDSON AND PERHAPS PAWNEE COUNTIES IN FAR SOUTHEAST NEB...BASED ON SATELLITE TRENDS AND RUC LOW LEVEL RH PROGS. MID CLOUDS AROUND A WEAK CIRCULATION EJECTING OUT OF CO ARE MORE EXTENSIVE AND SHOULD CROSS THE SOUTHEAST HALF OF THE CWA TONIGHT. BOTH FEATURES WILL HELP TO KEEP TEMPS IN A MILD RANGE COMPATIBLE WITH PREV FCST IN THE SOUTH...EXCEPT THAT FNB WILL REMAIN IN THE 30S WITH HIGHER DWPTS. THE NORTH HAS LOW DEW POINTS AND LIGHT WIND...AND SHOULD RADIATE INTO THE LOWER 20S. THE MODELS ARE FAIRLY SIMILAR THROUGH 24 HRS. HOWEVER...NONE OF THEM WAS DEEP ENOUGH WITH THE 5H HEIGHT FALL CENTER ARRIVING IN THE PAC NW THIS MORNING. A FAIRLY LARGE AREA OF 100-150 METER FALLS WILL PROBABLY REMAIN STRONGER THAN THE MODELS GIVE IT CREDIT FOR AS IT CROSSES THE AREA ON SUNDAY. EVEN SO...AVN AND ESPECIALLY NGM GENERATE AN AREA OF CLDS AT AND BELOW 700 MB DURING THE AFTN...AS WELL AS INCREASING THE LAPSE RATE AS COLDER AIR ADVECTS IN ALOFT WITH THE UPPER TROUGH. NGM EVEN SUGGESTS POTENTIAL INSTABILITY AT OFK DURING THE AFTN. I AM EXPECTING A SCENARIO SIMILAR TO THU WHEN DEEP MIXING FOR THIS TIME OF YEAR AND A PASSING TROUGH ALLOWED SOME RAIN/SNOW SHOWERS TO DEVELOP IN THE AFTN. SFC TEMPS WILL BE SOMEWHAT COOLER THAN THE LAST CASE...BUT TROUGH ALOFT IS STRONGER AND WILL COMPENSATE. UPPER DIFL FROM A JET MAX EMERGING FROM THE BASE OF THE TROUGH AND CROSSING MO ON BOTH NGM AND AVN COULD END UP ENHANCING VERTICAL MOTION...BUT THE NGM ALSO USES IT TO SLOW DOWN DAYTIME HEATING BY GENERATING HIGHER CLOUDS. I WILL ASSUME GOOD MIXING AND DECENT SUNSHINE BEFORE THE TROUGH TAKES OVER...AND LEAVE MAX TEMPS NEAR PREVIOUS FORECAST AND ALSO MOS. MODELS BEGIN TO DIFFER ON THE EXTENT OF LOW LEVEL COOLING SUNDAY NIGHT...WITH ETA RUNNING ABOUT 4C WARMER THAN AVN AT 850 MB BY MON MORNING AND NGM A LITTLE CLOSER TO ETA THAN AVN. ALL MODELS DEPICT LOW LEVEL WINDS BACKING INTO W/SW BY MON MORNING IN ADVANCE OF YET ANOTHER IMPULSE DIGGING INTO NRN PLAINS. THIS SHOULD CUT SHORT THE INITIAL COLD ADVN. WINDS SHOULD ALSO REMAIN UP SOMEWHAT...SO PREFER MID TO UPPER 20S OVER THE NGM MOS LOWER 20S FOR LOWS. AVN KEEPS THE LAXT IMPULSE MAINLY NORTHEAST OF THE AREA ON MONDAY...BUT WE DO GET CLIPPED WITH COLDER TEMPS. BREEZY CONDITIONS IN SW QUAD OF THE DIGGING SYSTEM SHOULD ALLOW DECENT MIXING AND ALLOW RELATIVE WARM MAX TEMPS FOR THE SITUATION. ONLY CONCERN IS THAT CI COVER COULD BE SUBSTANTIAL AS PACIFIC FIREHOSE JET PENETRATES INTO CENTRAL U.S. IN THE EXTENTED...ZONAL FLOW TAKES OVER ON TUESDAY WITH WARM ADVN SETTING UP DURING THE DAY IN ADVANCE OF WEAK LEESIDE TROUGH. LOW STRENGTHENS AND EJECTS EWD ON WED...GENERATING MILD TEMPS AT 850 ON BOTH MRF AND ECMWF...FOLLOWED BY A BACKDOOR INCURSION OF COOLER AIR ON THU. BARE GROUND HAS ALLOWED VERY MILD TEMPS FOR THIS TIME OF YEAR RECENTLY...AND WILL GO WITH RECENT TRENDS RELATING SFC TO 850 TEMPS. WHILE OVERNIGHT LOWS SHOULD NOT NEED MUCH MODIFICATION...I WILL TAKE HIGHS ABOUT 5F WARMER THAN NCEP GUID ON TUE...10F ON WED... AND 3F ON THURSDAY. DRY FORECAST LOOKS GOOD. .OMA...NONE POLLACK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 930 PM SAT JAN 8 2000 CNTR OF SFC HI PRES OFF VA CAPES LATE THIS EVENING WITH SKIES OVRCST MOST LOCATIONS ACRS CWA. LATEST KCAE RADAR SHOWING GENLY LGT RAIN STREAMING ACRS PORTIONS OF UPSTATE ATTM. 21Z RUC CONFIRMS THIS SHOWING WK ISENTROPIC LIFT ACRS WRN PORTIONS OF STATE. DEWPTS ATTM STILL MAINLY IN THE 30S TO 40 DEG OVR CWA. TEMPS CURRENTLY RUNNING A BIT ABV FWC GUIDANCE SO WL ADJUST OVRNITE MINS UPWARD JUST A BIT. WL ALSO MENTION 20 POP FOR ENTIRE CWA OVRNITE. OTHERWISE NO MAJOR CHANGES. .CAE...NONE. BC sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1000 AM EST SAT JAN 8 2000 LOWER CLOUDS CAME INTO COASTAL SECTIONS EARLIER THIS MORNING. ALTHOUGH THEY ARE SOMEWHAT OBSCURED BY HIGHER CLOUDS ON THE VISIBLE SATELLITE IMAGERY IT APPEARS THAT LOWER DECK IS BREAKING UP. SO WILL STAY THE COURSE WITH PARTLY CLOUDY FORECAST. OTHERWISE TROUGH OFF THE COAST DOES NOT LOOK TOO STRONG AT THIS TIME BUT IT SHOULD BE ENOUGH TO KEEP WINDS NORTHEAST TO EAST THROUGH THE DAY. SOUNDINGS SUPPORT CURRENT TEMPERATURE FORECAST. SO OVERALL NOT MANY CHANGES TO PUBLIC FORECAST. CWF...PG CONT TO INCR OVR CSTL WTRS. CONDS AT SCA CRITERIA AT 40 MI BUOY. MESO/RUC INDICATING AS TROF DEEPENS ALONG CST...HIGH PRES TO THE NORTH MOVES OFF THE COAST. PG WL RELAX AND WINDS WL DECR AS PER CURRENT PACKAGE. SUBSEQUENTLY DO NOT SEE ANY MAJOR CHGS FOR UPDATE. .CHS... SC...NONE. GA...NONE. /JCI sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 830 PM CST SAT JAN 8 2000 LOW OVER LA ASSOCIATED WITH FIRST VORT IS MOVING SLOWLY NORTHEAST. OVERRUNNING PCPN IN NE MS TO CONTINUE THROUGH MUCH OF THE NIGHT. SECOND RIPPLE IN FLOW COULD COME IN FROM THE WEST TNGHT. NET EFFECT WILL BE A CHANCE FOR LIGHT RAIN WHOLE CWA. TEMPS NOT TO DROP MUCH MORE IF ANY DUE TO SOUTHERLY FLOW AND CLOUDS. CURRENT FORECAST PACKAGE IS IN LINE WITH OBS AND RUC TRENDS. NO UPDATE. .MEM...NONE. WER tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 245 PM CST SAT JAN 8 2000 FORECAST QUANDARIES: PCPN PROBABILITIES/TEMPERATURES. CURRENT AWOS/ASOS OBSERVATIONS...SATELLITE IMAGERY...AND MOSIAC RADAR DATA ILLUSTRATING REGIONAL CLOUDINESS AND LIGHT RAINFALL ACROSS CWA/S WESTERN PORTIONS. LATEST SURFACE ANALYSIS/LAPS DATA DEPICTING LIGHT SOUTHERLY WIND FIELD WITH DEWPOINTS SPANNING MID 20S TO MID 30S. UPPER LEVEL CHART ANALYSIS/RUC SHOWING DEVELOPING SW FLOW WITH EMBEDDED VORT MAXES. 100KT+ 250MB SWLY JET OVER WESTERN TN. 12Z SAT MODEL RUN/S SURFACE AND UPPER LEVEL REGIONAL INITIALIZATION AND PROGGED EVOLUTION SIMILAR THROUGH 00Z TUE. SURFACE FEATURES EXPECTED TO PROGRESS FROM WEAKENING RIDGING INFLUENCES AREA CENTERED AS OF 18Z SAT OVER NE NC. MOVING EASTWARD. CURRENT REGIONAL AIRMASS PROGGED TO BE REPLACED BY A "MOISTURE RICH ONE" AHEAD OF AN APPROACHING COLD FRONT MOVING EASTWARD OUT OF THE CENTRAL U.S.. COLD FRONT EXPECTED TO BEGIN MOVING THROUGH WESTERN PORTIONS OF AREA AFTER 06Z MON. "RAPID" EASTWARD MOVEMENT ANTICIPATED ACROSS CWA AS FRONT MOVES INTO EASTERN TN BY 12Z MON. A SLIGHT PERTIBATIONS IN UPPER LEVEL FLOW ASSUMED TO MOVE ACROSS REGION BY 18Z SUN WITH MAIN UPPER LEVEL TROUGH PASSING OVER REGION DURING AN 12Z MON TO 00Z TUE TIME SPAN. IN AGREEMENT WITH LATEST MODEL DIAGNOSTIC DISCUSSION LEANING TOWARD AN AVN SOLUTION AFTER 00Z MON WITH "FAST" UPPER LEVEL FLOW MAKING SUCH A SOLUTION MOST LIKELY. AS FOR SKY CONDITIONS...MODELS PRESENTLY UNDERESTIMATING ATMOSPHERIC MOISTURE CONTENT...ESPECIALLY IN THE LOWER LEVELS. BELIEVE ENOUGH LOW LEVEL MOISTURE WILL BE PRESENT THROUGHOUT PERIOD TO SUPPORT MOSTLY CLOUDY SKIES. MAXIMUM AIRMASS MOISTURE POTENTIAL WILL BE ACHIEVED BEFORE 12Z SUN....CLOUDY SKIES AREA WIDE TONIGHT. AS FOR PCPN PROBABILITIES...AVN SHOWING LIKELY POPS THROUGH 12Z SUN WITH TOTAL RAINFALL AMOUNTS EXPECTED TO AVERAGE LESS THAN 0.25 INCH. NGM MOS SOLUTION POPS MAY BE "TOO LOW" THROUGH 00Z MON. WITH CURRENT MEASURABLE PRECIPITATION TRENDS AND SOME CONTINUED DRYNESS IN THE LOWER LEVELS..BELIEVE SOME RAINFALL WILL EVAPORATE BEFORE REACHING THE GROUND. WILL GO WITH CHANCE POPS REGIONWIDE ON SUNDAY WITH HIGHEST POPS WEST. WILL CONTINUE WITH CHANCE POP FORECAST THROUGH REMAINDER OF PERIOD. "QUICK" COLD FRONT PASSAGE BETWEEN 06Z-12Z MON WILL AID AS A FOCUSING MECHANISM FOR RAIN/SHOWER DEVELOPMENT...WITH LITTLE INDICATION OF INSTABILITY ASSOCIATED WITH TS DEVELOPMENT. WITH UPPER LEVEL TROF PASSAGE EXPECTED AFTER 12Z MON...NGM MOS VALUES COULD BE IN THIS CASE "TOO HIGH". WILL LEAN TOWARD HIGHER CHANCE POPS SUNDAY NIGHT AND CHANCE POPS CONTINUING THROUGH MONDAY AS LOW LEVEL MOISTURE PREVALENT ENOUGH FOR SCT PCPN POTENTIAL. AS FOR TEMPERATURES...WITH CLOUDY SKIES EXPECTED TONIGHT...AREA SHOULD SEE ONLY SLIGHT DIURNAL VARIATION IN HIGHS FROM THIS AFTERNOON TO SUNDAY MORNING LOWS. WITH HIGHS THIS AFTERNOON ONLY IN THE MID 40S TO AROUND 50 SOUTH...CLOSE TO AVN FAN EXPECTED LOW VALUES...WILL LEAN TOWARD NGM MOS LOWS. WITH PREFERRED AVN SOLUTION...WILL GO CLOSER TO FAN AVN HIGHS/ETA IN HOUSE BOUNDRY TEMPERATURE SCHEME VALUES FOR SUNDAY HIGHS. FAN AVN/NGM MOS LOWS "ON LINE" FOR SUNDAY NIGHT. WILL LEAN TOWARD WARMER AVN FAN VALUES FOR HIGHS ON MONDAY. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 038/057/047/060 4333 CSV 035/053/045/056 3433 .BNA...NONE. $$ 14 JBW tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 851 PM EST SAT JAN 8 2000 VAPOR LOOP INDICATES INIT S/W SHEARING RAPIDLY NEWD ACROSS THE REGION THIS EVE. PLENTY OF MID DECK CLDNS ARND AND EVEN A BIT DEEPER MOISTURE ALONG THE WRN SLOPES...OTRW PRECIP CONTS TO BE VERY SPOTTY AND MAINLY ALOFT ATTM. MAIN QUEST OVERNGT AS TO WHETHER OR NOT ANY ADTNL/SIG PRECIP WILL RE-DVLP AS CURRENT VORT EXITS AND UPR FLOW BEGINS TO BACK IN ADVANCE OF NEXT STRONGER S/W APCHG FROM THE MIDWEST. WITH RAOBS STILL SHOWING A POCKET OF SFC-7H DRY AIR PLUS LACK OF UPSTREAM PRECIP ON REGIONAL RADARS...APRS CHCS OF SIG EVAP COOLING INCLUDING FROZEN PRECIP RATHER SMALL OVRNGT. ONLY EXCEPTIONS PSBLY IN THE NRN NC MTNS GIVEN PRECIP AXIS HANGING TO THE SOUTH AND DEEP VALLEYS IN SE WVA WHERE SOME FRZG -DZ COULD DVLP LATE AS DRY SLOT ALF BEHIND INIT VORT COMES IN OVER LOW LVL RH. OTRW...LATEST MESO-ETA/RUC SHOW BEST RETURN LIFT DVLPG TO THE SW LATE AND THEN OVERSPREADING THE REGION DURING SUNDAY AFTN. MAY KEEP IN A LOW POP NRN NC MTNS/SW VA GIVEN PTNL FOR MOISTURE AXIS ALONG SRN JET TO BEGIN LIFTING NWD LATE AS MODELS LOOK SLOW WITH RH IN FAST FLOW ALOFT. OTRW THINK CAN GO WITH MNLY CLDY SKIES/SPRINKLES OVERNGT FOR THE MOST PART. TEMPS LOOK ON TRACK...ALTHO WILL UP FCST LOWS IN THE VALLEYS SINCE MID 20S APR A BIT COLD GIVEN CLDNS AND LACK OF MUCH PRECIP ESPCLY ON THE VA SIDE. .RNK VA...NONE. WV...NONE. NC...NONE. JH va EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 930 PM PST SAT JAN 8 2000 UPPER LEVEL HIGH PRESSURE WILL REMAIN OFF THE CALIFORNIA COAST THROUGH EARLY NEXT WEEK. WEAK WEATHER DISTURBANCES WILL BRING OCCASIONAL HIGH CLOUDS. HIGH PRESSURE BUILDING INTO THE GREAT BASIN TONIGHT WILL PRODUCE LOCALLY GUSTY NORTH TO NORTHEAST WINDS NEAR THE MOUNTAIN CANYONS AND PASSES. PRESSURE GRADIENTS ARE OSCILLATING SOMEWHAT THIS EVENING...THOUGH WE ARE SEEING SOME PRESSURE RISES IN THE GREAT BASIN. ONSHORE GRADIENTS HAVE ACTUALLY INCREASED TO OUR EAST. WE MIGHT SEE SOME WIND THROUGH PASSES AND CANYONS LATE TONIGHT...THOUGH FURTHER PRESSURE RISES WILL BE NEEDED FOR 20-30 BELOW THE CAJON PASS. THE NEW 00Z ETA/NGM ARE SHOWING A QUICK RETURN TO ONSHORE FLOW BY THE AFTERNOON...ENOUGH THAT SOME PATCHY LOW CLOUDS AND FOG MIGHT COME BACK SUNDAY NIGHT TO THE COAST...ESPECIALLY GIVEN THAT DEW POINTS ARE FAIRLY HIGH EVEN NOW IN SOME COASTAL AREAS. LOCAL FOG MAY EVEN BE POSSIBLE THIS EVENING BEFORE THE DRAINAGE KICKS IN. THE HIGH CLOUDS ARE HIGH ENOUGH THAT THEY ARE MOSTLY A NON-ISSUE FOR OUR TEMPS/CONDITIONS. THE EARLIER UPDATE...WHICH HAD THE INCREASE IN SOME OF THE WINDS FOR LATE TONIGHT/EARLY SUNDAY WAS BASED ON THE RUC...AND THE FACT THAT SANDBERG HAD GUSTY WINDS ALREADY. THE ETA/NGM UNDOES SOME THAT THOUGH. HOWEVER...THE LOWERING OF THE TEMPS FOR TONIGHT LOOKS GOOD GIVEN THAT WE ARE AVERAGING ONLY ABOUT A DEGREE OR TWO WARMER WEST OF THE MOUNTAINS VERSUS 24 HOURS AGO. IN THE EXTENDED...IT LOOKS LIKE WE WILL HAVE ONSHORE FLOW FOR MOST OF NEXT WEEK. 12Z ECM IS SIMILAR TO THE MRF WHERE THE TROUGHING IS TOO FAR WEST FOR ANY LIKELIHOOD OF PRECIP. HOWEVER...IF A SHORT WAVE FORMS ON THE SOUTH SIDE AND CAN MAINTAIN STRENGTH...OR AT LEAST GIVE US A DEEP MARINE LAYER WITH STRONG ONSHORE FLOW...THEN WE COULD HAVE A VERY SLIGHT CHANCE OF PRECIP SOMEWHERE BETWEEN THU AND SAT. THE MODELS ARE TRENDING AWAY FROM THIS GRADUALLY THOUGH. AN UPDATE WILL BE ISSUED BY 10 PM FOR A FEW MINOR THINGS...ESPECIALLY SOME COASTAL FOG WORDING. SAN 0000 .SAN...NONE MAXWELL ca AREA FORECAST DISCUSSION..CORRECTION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 300 AM CST SAT JAN 8 2000 SHORT TERM FORECAST PROBLEM IS STRATUS AND FOG MOVING UP FROM SOUTH. BOTH 06Z ETA AND LATEST RUC FORECAST LOW LEVEL MOISTURE PUSHING UP INTO SE MN AND WESTERN WI THIS MORNING. WILL HOLD OFF ON FOG ADVISORY FOR NOW BUT WILL NEED TO WATCH. WILL MENTION AREAS OF DENSE FOG AND POSSIBLY SOME FREEZING DRIZZLE. THIS SHOULD HOLD TEMPS DOWN A FEW DEGREES FROM YESTERDAY. OTHERWISE ..CONCERNS ARE THE PRECIP CHANCES FOR LATER INTO THIS EVENING..AND ON MONDAY AFTERNOON. OVERALL..LIKE AVN MODEL. IT LOOKS LIKE IT HAS BEST HANDLE ON VORT PATTERN OVER ROCKIES AT AROUND 06Z AND HAS VERY GOOD CONSISTENCY FOR LAST 3 RUNS. ETA AND NGM HAVE COME AROUND TO THE SHARPER UPPER TROUGH OVER THE PLAINS BY THIS EVENING. BEST LAYER (850-700) Q VECTOR CONV FAVORS SOUTH CENTRAL MN THIS AFTERNOON AND THEN BETTER PRECIPITABLE WATER COMES INTO PLAY OVER EASTERN MN THIS EVENING. PV AT 400 MB PASSING TO THE SOUTH OF MN BUT ADVECTION DECENT INTO SE MN AND WESTERN WI THIS EVENING. BASED ON PASSED PRECIP PATTERNS DURING PAST MONTH OR SO..WILL FAVOR EASTERN CWA FOR THIS EVENING AND UP POPS OVER MOS...CLOSER TO AVN. FOR MONDAY...THERE IS REMARKABLE AGREEMENT LOOKING AT DPROG/DT ON AVN FOR MONDAY AFTERNOON FOR VORT SLIDING TOWARD MN/IA BORDER AREA. FORECAST LAPSE RATES (7000-500) QUITE STEEP ON MONDAY..NEAR 7.5 C. WILL AGAIN RAISE POPS FOR LIGHT SNOW..PRIMARILY NE PART OF CWA. LOOKS WINDY IN SW MONDAY AFTERNOON AS WELL WITH COLD ADVECTION. .MSP...DENSE FOG ADVISORY THIS MORNING..MNZ074>078..MNZ082>085..MNZ091>093 RICHARDSON mn SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 220 AM CST SUN JAN 9 2000 SHRTWV MOVG ACRS THE ROCKIES WAS TRIGGERING SOME -SN OVR WY EARLY THIS MRNG WITH ANOTHER ON THE HEELS MOVG ASHORE OVR PAC NW. CLR SKY OVR MOST OF CWA WITH FOG/DRZL OVR EXTREME SERN CWA AS MSTR POOLED IN SFC TROF. ONLY MINOR TWEAKS TO ONGOING PACKAGE THIS MRNG AS SHRTWVS IN PROGRESSIVE PATTERN CONT OVR THE CONUS. ROTATION ON SATELLITE IMAGERY MOVG OVR CO LKS TO BE ON A HEADING S OF AREA WITH CLD TOPS WARMING AND WL GO WITH ETA/NGM DRY TRACK OF TAKING THIS BOLT OF ENERGY INTO THE SRN PLNS LTR TDA...WITH MID LVL TROF AXIS CLR OF CWA LTR THIS AFTN. LLVLS RMN DRY WITH RUC/MESOETA SLOWLY PUSHING DRY DPS INTO OUR FOG AREAS AS THE MRNG PROGRESSES...SOME VIRGA MAY BE SEEN EARLY THIS AFTN...BUT WL NOT MENTION ANY SPRINKLES WITH THIS ISSUANCE. NGM PROG IS A BIT MORE AGGRESSIVE WITH COLD ADVCTN AS LLVL WND INCRS THIS AFTN...BUT ETA STILL PROGS ARND 0 DEG C AT 850MB... WHICH WOULD SPPRT UPR 40S GUIDANCE FOR HIGHS TDA WITH BREEZY MENTION. WL DECIDE AT ISSUANCE WHETHER AFORE MENTIONED FOG COUNTIES NEED TO BE CUT-OUT AND QUARANTINED FOR THE MORNING. TNGT...CLRG SKY AS SHRTWV RIDGE MOVS OVR THE CNTRL PLNS. ANOTHER SHRTWV IS PROGGED TWD THE NRN PLNS...WL TURN THE SFC WND BACK TO THE WEST...AND WL CONT THE LEAN TWD COOLER FWC FOR LOWS. MON...VORT MAX MOVS ACRS THE NRN PLNS PRVDG AREA WITH ANOTHER WND SHIFT...SOME CLDS...AND A REINFORCING SHOT OF COOL AIR. AVN IS THE WARMER OF THE BIG THREE AS IT ONLY SKIRTS THE AREA WITH THE COLD AIR...WL FOLLOW ALONG AND PROG HIGHS NR TDAS. AVN/ETA/NGM SOLNS ALSO PROG NR 50 KT 850 MB WND OVR THE NERN QUAD OF NEB...WL MAKE WINDY MENTION FOR MOST OF CWA...WITH DOWNSLOPE COMPONENT HELPING THE TMPS. EFP LKS FINE...DRY AND SLGTLY ABOVE SEASONAL TMPS WITH SHRTWVS IN ZONAL FLOW. .GID...NONE. 9 ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 250 AM CST SUN JAN 9 2000 AS MENTIONED IN NATIONAL DISCUSSIONS...STRONGER PACIFIC FLOW HAS CREATED MORE COMPLEX PATTERN AS IMPULSES EJECT ACROSS THE DIVIDE AND RACE THROUGH THE MIDWEST. FORECAST CONCERNS BEGIN WITH FOG THREAT TODAY AND PRECIPITATION CHANCES TONIGHT AND MONDAY. AT 08Z PSUEDO WARM FRONT AND ASSOCIATED STRATUS/FOG EXTENDED FROM SOUTHERN WISCONSIN WEST ALONG MINNESOTA-IOWA BORDER AND MAKING STEADY PROGRESS NORTH. MOST OBSERVATIONS SOUTH OF FRONT SUGGEST VERY SOUPY CONDITIONS WITH DENSE FOG AND OCCASIONAL DRIZZLE. RUC AND ETA MODELS SEEM TO HAVE A GOOD HANDLE WITH 925 MB MOISTURE AND REALLY SOCK OUR FORECAST AREA IN THIS MORNING. WILL GO AHEAD AND HOIST DENSE FOG ADVISORIES FOR SOUTHERN HALF OF FORECAST AREA. NORMALLY WOULD EXPECT SOME IMPROVEMENT IN LATE MORNING...BUT WITH SUCH WARM...MOIST FLOW HEADING NORTH OVER PATCHY SNOW COVER...SEE NO REASON WHY CONDITIONS WILL IMPROVE DRASTICALLY TODAY. WILL LEAVE ADVISORY IN EFFECT ALL DAY AND LET DAY SHIFT MAKE CHANGES AS NEEDED. CONSIDERING HOW MUCH "NOISE" THERE IS IN THE FLOW WITH SO MANY WEAKER IMPULSES...SHORT TERM MODELS IN SURPRISINGLY GOOD AGREEMENT. AVN MODEL HAS BEEN MOST CONSISTENT AND FAVORED. SHORT WAVE TROUGH OVER COLORADO FORECAST TO MOVE JUST SOUTH OF FORECAST AREA BY TONIGHT. BEST DYNAMICS STAY SOUTH BUT APPEARS THERE MAY BE ENOUGH FORCING TO RAISE POPS FOR TONIGHT...BEFORE ENDING FROM WEST TO EAST DURING LATE EVENING. THICKNESS VALUES AND MODEL SOUNDINGS SUGGEST MAY BE WARM ENOUGH FOR RAIN OR MIXTURE BEFORE COLDER AIR FILTERS IN JUST ABOUT TIME PRECIPITATION ENDS. ANOTHER SHORT WAVE TROUGH RIGHT ON THE HEELS OF THE FIRST ONE ENTERS THE PICTURE FROM THE NORTHERN ROCKIES ON MONDAY. THIS APPEARS TO HAVE BETTER DYNAMICS FOR OUR AREA...AND WOULD BE CERTAINLY ALL SNOW. WILL LEAVE MARGINAL POPS GO FOR NOW AND LET LATER FORECASTS REFINE THIS. COORDINATED WITH DMX..DVN..MKX..MPX AND GRB. THANKS. .LSE...DENSE FOG ADVISORY FOR TODAY ALONG/SOUTH OF INTERSTATE 90 IAZ008>011-018-019-029-030-MNZ086>088-094-095- WIZ041>044-053>055-061 SHEA wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 1000 AM EST SUN JAN 09 2000 SERIES OF SHORTWAVES CONTINUE TO AFFECT THE AREA IN FAST ACTIVE ZNL FLOW ACROSS THE COUNTRY. MDLS ARE NOTORIOUS FOR HAVING PROBLEMS IN DEALING WITH THE TIMING AND INTENSITY OF EACH SHORTWAVE IN THIS TYPE OF PATTERN. ONE SUCH SHORTWAVE AFFECTED THE AREA OVRNGT WITH TRACE AMTS OF -RA/PE. THIS SYSTEM IS NOW WELL E OF THE AREA. YET ANOTHER SHORTWAVE OVR THE OH VLY THIS MORNING WL TRACK EWD PASSING JUST TO OUR N THIS AFT/EVE. DECENT WARM ADVECTION/ISENTROPIC LIFT AHEAD OF THE SHORTWAVE IS RESULTING IN A WIDESPREAD AREA OF RAIN OVR SW VA AND WV TRACKING ENE. 06Z ETA AND LATEST RUC SUGGESTS THAT RAIN WL LINGER INTO EARLY EVE AS THIS SHORTWAVE PASSES BY TO THE N...THEN PCPN SHUD CUT OFF WELL BFR MIDNIGHT. THE STRONGEST SHORTWAVE WL APPROACH ON MON MORNING...PASSING THRU THE AREA DURING THE AFTERNOON. THE ASSOCIATED SFC FNT WL CROSS THE AREA DURING THE AFTERNOON. AS FAR AS THE FCST IS CONCERNED...WILL BUMP POPS UP ALL AREAS FOR THIS AFTERNOON. SOME EVAPORATIVE COOLING WILL OCCUR WHICH WL RESULT IN SOME COOL AIR DAMMING E OF THE MTNS THIS AFTERNOON. THIS WL HOLD MAX TEMPS DOWN A BIT AND I ADJUSTED THEM AS NEEDED. WL LET THE CHC OF RA LINGER INTO EARLY TNGT THEN BRING THE CHC BACK IN LATE TNGT. OTHERWISE...NO CHGS 2ND AND 3RD PDS. .LWX...NONE. DMW md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1100 AM EST SUN JAN 9 2000 ...FOG IS MAIN UPDATE CONCERN... VIS IMAGERY SHEDDING LIGHT ON EXTENT OF LOCALLY DENSE FOG OVER UPR MI. BR/FG WIDESPREAD IN DICKINSON/IRON COUNTY WITH FLP SUPPORTING CONTINUATION THU AFTERNOON. SW COUNTIES REMAIN M SUNNY WHILE BKN SC DECK DISSIPATING IN CMX PER ASOS/PHONE CALL TO OBSERVER. ELSEHWERE MOSTLY SUNNY WITH PATCHY FOG LINGERING. LOWERED TEMPS IN DICKINSON/IRON COUNTIES TO REFLECT REDUCED ISOLATION. WATCHING ADVANCE OF WARM FRONT THRU WI W/ SFC DEWPTS IN THE 30S/FG SURGING NORTH BEHIND FRONT. MESOETA/RUC AGREE THAT THIS LL MOISTURE WILL NOT ADVECT INTO S CWA UNTIL 21-00Z. .MQT...NONE. WOLF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1004 AM EST SUN JAN 9 2000 INVERTED SFC TROF HAS SET UP ALONG THE CST W/ MSAS ANALYSIS SHOWING A SERIES OF WEAK LOWS ALONG IT. BOTH LATEST RUC & MESO-ETA SHOW A SINGLE PRIMARY LO MOVING UP THE CST THRU THE AFTN ALONG W/ AN UPR S/WV. ONLY WEAK LIFT EXPECTED FROM THESE FEATURES AS WELL AS ANOTHER VORT PASSING WELL N OF THE AREA LATER THIS AFTN. ALSO SEEING AREA OF BEST ISENTROPIC LIFT SHIFT EWD AS WELL. AS EXPECTED THE ATMOS HAS MOISTENED QUITE A BIT IN 24HR W/ 12Z MHX & CHS RAOBS EACH SHOWING PWATS GREATER THAN 1. COLUMN WILL CONTINUE TO MOISTEN AS H7-H8 FLOW BACKS TO MORE SW AHEAD OF TROF NOW OVER THE PLAINS STATES. NEAREST PRECIP ON 88D MOSAIC STILL BACK W OF A KDAN-KGSO-KCLT-KAND LINE & MOVING NE. WILL CONTINUE CHC POPS BUT WILL WORD AS LATE AFTN. BEST INSTABILITIES STILL WELL OFFSHORE BUT CREEP BACK TOWARD CST THRU THE DAY... WILL CONTINUE TO HOLD OFF MENTION OF TRW. TEMPS MAY NEED TO COME DOWN BASED ON LO-LVL THICKNESSES FROM MORNING SOUNDINGS & LAMP GUIDANCE (WHICH IS A LITTLE HIGH BASED ON 15Z TEMPS). WILL PROBABLY DROP A CAT W/ THIS UPDATE. CWF: WINDS TRULY VRB OUT THERE ATTM W/ FPSN7 SHOWING N WINDS 10- 15KT & 41004 SE LESS THAN 5KT. WILL MAINTAIN VRB BECMG SW S OF LITTLE RIVER BUT WILL DECIDE ON INITIAL DIRECTION N OF THERE BASED ON LATER REPORTS. .ILM...NONE. LGE nc AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 939 AM CST SUN JAN 9 2000 BASED ON SATELLITE...SFC OBS...THE LATEST RUC AND ETA...THE CURRENT FORECAST HAS A GOOD HANDLE ON THE SITUATION. THEREFORE...NO UPDATES NEEDED AT THIS TIME. .ABR...NONE MOHR sd SOUTHEAST TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 950 AM CST SUN JAN 9 2000 GOOD ROUND OF FOG LAST NIGHT AND THIS MORNING WITH MOST OF THE AIRPORTS REPORTING VISIBILITIES AT 1 MILE OR LESS AS OF 900 AM. CXO/LBX/PSX/IAH AT <=1/2 MILE. WEAK BUBBLE HIGH OVER SW ZONES WITH WINDS RESPONDING ACCORDINGLY. AFTER CLOSE SCRUTINY OF RUC SOUNDINGS BELIEVE FOG SHOULD DISSIPATE BETWEEN 11 AND NOON. CURRENT DENSE FOG ADVISORY RUNS THROUGH 1030 AM...WILL LET IT RIDE AND MAY REISSUE AT THE LAST MINUTE BASED ON OBS AT THAT TIME. AFTER THE FOG DISSIPATES SKIES SHOULD CLEAR GRADUALLY OVER THE EASTERN HALF OF THE AREA...QUICKER CLEARING IN WESTERN PORTIONS. TEMPS MAY NEED A NUDGE UP IN NW ZONES AS SKIES ARE DRIER AND SW WINDS WOULD FAVOR A QUICK TEMPERATURE RISE WILL HOLD OFF FOR THE TIME BEING BUT WILL MONITOR CLOSELY. .HGX...NONE. 45/41/DEB PREV PRELIMS... CLL BU 069/043 073/043 075 42000 IAH EU 073/045 075/045 076 42000 GLS EU 066/054 071/053 072 42000 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 235 PM CDT SUN JAN 9 2000 FORECAST QUANDARIES: FIRST PERIOD CONVECTION STRENGTH...TEMPERATURES. CURRENT ASOS/AWOS OBSERVATIONS AND REGIONAL SATELLITE IMAGERY SHOWING CWA UNDER LOW LEVEL CLOUDINESS IN ASSOCIATION WITH SW FLOW. SOME BREAKAGE IN CLOUD COVER NOTED AS DRY SLOT DEVELOPING OVER EASTERN PORTIONS. BREAKAGE HAS ALLOWED TEMPERATURES TO RISE INTO THE LOW TO MID 50S WITH DEWPOINTS VALUES CLOSE BEHIND. 18Z LAPS SOUNDING STILL SHOWING ATMOSPHERE STABLE WITH LIFTED INDICIES +7.5 AND K VALUES MID 10/S. UPPER LEVEL CHART ANALYSIS/RUC SHOWING STRONG SWLY UPPER LEVEL FLOW WITH 250 MB 100KT+ JET CENTERED OVER MID STATE. RUC PROGGING SHORTWAVE/VORT MAX PASSAGE IN UPPER LEVEL FLOW THIS THROUGH THE AFTERNOON. MAIN CONCERN OF FORECAST PERIOD CENTERS AROUND STRENGTH POTENTIAL OF CONVENTION FIRST PERIOD. PER LATEST MODEL DIAGNOSTIC DISCUSSION ...AVN PREFERRED FOR SOUTHERN STRENGTH OF SYSTEM WITH STRONG DIVERGENCE FORECAST WITH EXPECTED DEVELOPMENT OF JET COUPLET. AS POINTED OUT BY 1630Z SUN STORM PREDICTION CENTER DAY 1 CONVECTIVE OUTLOOK... STRONG DYNAMIC FORCING FOR UPWARD MOTION ASSOCIATED WITH SYSTEM WILL AID IN POTENTIAL FOR SIGNIFICANT THUNDERSTORM ACTIVITY IF SUFFICIENT INSTABILITY DEVELOPS. FRHT65/FRH65 SHOWING GREATEST INSTABILITY POTENTIAL AFTER 06Z SUN WITH LI VALUES APPROACHING -3...SUGGESTING MARGINAL SEVERE THUNDERSTORM ACTIVITY. AVN MODEL SOUNDING FOR SHOWING BNA SWEAT VALUES 305...CSV 370 AT 06Z MON. WITH ATMOSPHERE "RAPIDLY" STABILIZATION AFTER 12Z MON AS SURFACE FRONT MOVES RAPIDLY ACROSS CWA BY 12Z. LOOK FOR QUICK MOVING THUNDERSTORMS WITH GUSTY WINDS..SOME DAMAGING. WITH WET BULB ZERO HEIGHTS FALLING TO AROUND 5 KFT AT BNA BY 12Z...HAIL DEVELOPMENT PROBABLE WITH SOME LARGE HAIL LIKELY. WILL WORD FORECAST AS SHOWERS AND THUNDERSTORMS DEVELOPING WITH STRONGEST THUNDERSTORMS ...SOME POSSIBLY SEVERE AFTER MIDNIGHT. HAVE NO REASON TO QUESTION AVN FAN LIKELY POPS FOR FIRST PERIOD. SCATTERED MORNING POPS CENTRAL AND EAST. MODELS SHOWING REMAINDER OF FORECAST PERIOD AS "DRY" WITH DECREASING CLOUDINESS BEGINING AS SOON AS 12Z MON OVER FAR WESTERN PORTIONS OF CWA. WILL GO WITH MOSTLY SUNNY SKIES AND MOSTLY CLEAR NIGHTS THROUGH REMAINDER OF FORECAST PERIOD. AS FOR TEMPERATURE FORECAST...WILL GO CLOSE TO AVN FAN VALUES FOR LOWS THROUGH PERIOD. WITH WINDS APROACHING BREEZY CRITERIA MON AFTERNOON...WILL LEAN TOWARD MORE "ROBUST" FAN AVN VALUES FOR HIGHS ON MONDAY. AVN MAY BE TOO AGRESSIVE ON HIGHS FOR TUESDAY AND WILL UNDERCUT A FEW DEREES. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 048/060/036/062 6300 CSV 044/055/032/058 6400 .BNA...NONE. $$ 14 JBW tn