AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO CA 900 AM PST SAT FEB 16 2002 CLOSED UPPER LOW OUT NEAR 38N/130W IS MOVING DUE EAST. IR SATELLITE IMAGERY INDICATES ASSOCIATED FRONTAL BAND IS CURRENTLY CROSSING 125W HAS BEEN SHOWING SOME ENHANCEMENT OVER THE PAST COUPLE OF HOURS AS A JET MAX SWINGS AROUND THE BASE OF THE LOW AND UPPER DIFFLUENCE INCREASES. TIMING THE ONSET OF PRECIPITATION IS THE PRIMARY SHORT TERM FORECAST CONCERN. THIS SYSTEM IS DEFINITELY MOVING FASTER THAN WHAT WAS ANTICIPATED 24 HOURS AGO. RADAR IS DETECTING RAINFALL ABOUT 100 MILES WEST OF POINT ARENA. THE RAIN BAND IS MOVING EAST AT ABOUT 20 MPH WHICH WOULD BRING RAIN TO THE SONOMA COUNTY COAST EARLY THIS AFTERNOON. THIS IS CONSISTENT WITH THE 12Z RUN OF THE ETA AND 06Z RUN OF THE PACRUC MODEL WHICH BOTH SHOW RAINFALL DEVELOPING IN SONOMA COUNTY BY 21Z AND THEN EAST TO THE DELTA AND SOUTH TO MONTEREY BAY BY 00Z. WILL UPDATE ZONES TO INCREASE POPS TO CATEGORICAL IN NORTH AND WEST ZONES THIS AFTERNOON. RAIN WILL SPREAD OVER THE REMAINDER OF THE CWA THIS EVENING. ISOLATED THUNDERSTORMS ARE POSSIBLE TONIGHT AS THE UPPER LOW TRACKS INLAND AND THE AIRMASS DESTABILIZES. AIDING THUNDERSTORM DEVELOPMENT WILL BE A GOOD SHEAR PROFILE FROM THE SURFACE TO 10K FEET. THERE SHOULD BE ENOUGH COLD AIR WITH THIS SYSTEM TO BRING SNOW LEVELS DOWN TO 3500- 4000 FEET...LOW ENOUGH FOR A DUSTING OF SNOW ON THE HIGHEST PEAKS. AN UPSTREAM SHORTWAVE TROUGH SEEN ON SATELLITE NEAR 50N/150W WILL BE WHAT KEEPS OUR CLOSED LOW MOVING EAST. IT WILL DROP INTO THE PACIFIC NW AND FAR NRN CA ON SUNDAY AND SCATTERED SHOWERS SHOULD CONTINUE THROUGH SUNDAY EVENING. A SHORTWAVE RIDGE WILL BRING DRY WEATHER BACK TO OUR REGION BRIEFLY SUNDAY NIGHT AND MOST OF MONDAY. RAIN CHANCES WILL RETURN BY MONDAY EVENING WHEN THE NEXT SYSTEM TAKES AIM AT THE PAC NW AND NORTHERN CA. STS/SFO 896 LVK/SJC 796 MRY 686. DYKEMA .SFO...TDA...SCA...POINT ARENA TO POINT SUR. ca SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE IDAHO 145 PM MST SAT FEB 16 2002 TRACE OF SNOW LAST NIGHT AT BURNS AS UPPER LOW OPENED UP AND MOVED MAINLY SOUTH TO N AND FASTER THAN 12Z RUNS - WAS OVER MOUTH OF COLUMBIA AT 12Z INSTEAD OF CLOSER TO 18Z - NOW WELL NW OF BOISE CWFA. LATEST RUC IS EVEN FASTER THAN AVN AND BRINGS IN H5 LOW TO NEAR SFO AT 6Z WITH AVN STILL A BIT OFFSHORE. SO WILL GO WITH AVN'S FASTER AND MORE SOUTHERN TRACK. THAT UPPER LOW OFF SFO THIS AFTERNOON HAS STRONGER WESTERLY KICKER WITH SPEED MAX AROUND 38N FROM 165W TOWARD 145W, FAVORING FASTER AVN SOLUTION (LOW NEAR ELKO MIDDAY SUNDAY) OVER SLOWER ETA FOR SYSTEM (LOW CLOSER TO SHASTA MIDDAY SUNDAY). WE HAVE A PROGRESSIVE RIDGE OVER ROCKIES WHICH SHOULD ALLOW UPPER LOW TO MOVE IN (BUT STILL WEAKEN) AND THE STRONGER KICKER SHOULDN'T BE DISCOUNTED EVEN THOUGH IT TURNS FROM A WRLY SPEED MAX INTO A NWRLY MAX DIVING DOWN THE BACK SIDE OF THIS NEXT UPPER LOW. SO WILL GO WITH AVN WHICH MEANS INCREASING CLOUDS TONIGHT. ON SUNDAY HARNEY/MALHEUR AND SW IDAHO MOUNTAINS-HIGHLANDS WILL GO LIKELY RAIN WITH 1-3" SNOW ABOVE 5K'...HIGH CHANCE POPS FROM ONO-BOI AND MID CHC POPS BKE TOWARDS TWF. PLAN A 20 POP FOR MYL SUNDAY WITH SRN TRACK OF NEXT UPPER LOW...BUT WITH RIDGE OVER ROCKIES MAY SEE MORE ENERGY OVER SW IDAHO SUNDAY AFTERNOON. UPPER LOW OPENS UP OVER SE IDAHO SUNDAY NIGHT BUT FOR SUNDAY EVENING PLAN TO GO LIKELY FOR SRN ID MTNS AND CAMAS PRAIRE AS WELL AS EAST OF BOISE IN UPR T.V. PLAN CHANCE POPS ACROSS THE REST OF THE NW PART OF THE CWA. THIS IS DUE TO A SHORTWAVE MORE IN THE NRN BRANCH CROSSING INTO EASTER OREGON TOWARDS EARLY MONDAY THEN ACROSS MYL-BOI AROUND NOONTIME...WITH SCT VALLEY RAIN AND MTN SNOW SHOWERS. AVN IS A BIT DEEPER WITH THIS FEATURE OVER BOTH THE 00Z MRF AND 12Z ETA AS THE AVN IS CARRYING (AT 18Z MONDAY) THE H5 546DM COUNTOUR S OF BOISE WHILE THE ETA HAS IT WAY UP IN THE IDAHO PANHANDLE. CHANCE POPS EVERYWHERE EAST OF BNO (20 POP) MONDAY WITH THIS FEATURE. SHORT WAVE RIDGING BUILDS IN MONDAY NIGHT BUT MOIST WARM ADVECTION WITH THETA-E RIDGE PUSHES INTO THE CASCADES BY TUESDAY MORNING PROBABLY WITH VIRGA/SPRINKLES-FLURRIES INTO SE OREGON BY MORNING. THE TUESDAY SYSTEM LOOKS TO BE A "GOOD" PRECIP MAKER WITH LIKELY POPS AND RISING SNOW LEVELS BUT STILL SOME SNOW ACCUMULATION EXPECTED TUESDAY. HIGHEST POPS NEXT SEVEN DAYS WITH THIS FEATURE. WILL GO WITH LIKELY POPS OVER SE OREGON ALL TUESDAY AND OVER SW IDAHO FOR 'AFTERNOON' PER AVN/MRF MODEL SOLUTIONS, QPF, AND MEXMOS EVEN THO IT'S DAY 3. ASSOCIATED CD FNT COMES NOW RIGHT ON THE HEELS OF THE WARMFRONT CROSSING SE OREGON TUESDAY NIGHT AND THROUGH MAGIC VALLEY PROBABLY EARLY WEDNESDAY MORNING. EXPECT SCATTERED MAINLY MOUNTAINS SNOW SHOWERS WEDNESDAY BEHIND CDFNT. RIDGE BUILDS IN THURSDAY BUT MOIST WAA IS ADVERTISED IN 12Z AVN MAINLY TOWARDS CASCADES SO WILL LEAVE POPS OUT STILL FOR THURSDAY AND TREND TOWARDS LESS CLOUD COVER ESPECIALLY SW IDAHO VALLEYS AND OWYHEES-HIGHLANDS. WILL STICK WITH CURRENT EXTENDED A BIT COOLER WITH CHANCE POPS FOR FRIDAY AND SATURDAY AS UPPER JET AXIS AND COLD FRONTAL PASSAGE OCCUR SOME TIME BETWEEN THURSDAY NIGHT AND FRIDAY AND COLD TROFFINESS LINGERS OVER THE CWFA SATURDAY THOUGH SOME DRY RIDGING WORKS INTO HARNEY CO TOWARDS NEXT SATURDAY. .BOI...NONE. MILLS id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 617 PM CST SAT FEB 16 2002 EVENING UPDATE: LOOKING AT THE LATEST SATELLITE TRENDS...MUCH OF THE WESTERN EDGE OF THE DIURNALLY DRIVEN CU HAS DISSIPATED. THE GREATEST CONCENTRATION OF CLOUD COVER IS UP ACROSS WISCONSIN...AND OVER NORTH AND EAST INDIANA. LOOKING AT THE LATEST RUC...THE POSSIBILITY FOR ADDITIONAL STRATO-CU AFFECTING OUR NE COUNTIES EXISTS LATER IN THE NIGHT...BUT THE BETTER MOISTURE REMAINS TO THE NORTH AND EAST. SO...WILL BACK OFF ON CLOUDS...AND GO PARTLY CLOUDY NE COUNTIES...AND MOSTLY CLEAR OR CLEAR OVER THE REMAINDER OF THE REGION. DISCUSSION FOR THE REST OF THE AFTERNOON ISSUED FORECAST PACKAGE IS BELOW. NOLES AFTERNOON DISCUSSION: MAIN CHALLENGES FOR THIS PACKAGE WILL BE SYSTEMS COMING THROUGH MONDAY NIGHT INTO TUESDAY AND THEN AGAIN THURSDAY INTO FRIDAY. 12Z MODELS IN DECENT AGREEMENT THROUGH THE SHORT TERM. AVN SEEMS A TAD WETTER WITH EACH OF THE TWO UPCOMING SYSTEMS...BUT OVERALL HANDLING OF THE MAJOR FEATURES VERY SIMILAR. SFC AND ASSOC UPPER LOW CURRENTLY OVER SOUTHERN CANADA TO CONTINUE TO MOVE AWAY FROM THE REGION. SFC HIGH PRESSURE AND RISING HEIGHTS ALOFT WILL DOMINATE THROUGH MONDAY WHEN LOW LEVEL MOISTURE WILL RETURN AHEAD THE NEXT SYSTEM. BY THEN THE SFC AND UPPER RIDGE WILL BE EAST OF THE CWA AND A SHORT WAVE MOVING NORTHEAST OUT THE MAIN UPPER LOW OVER THE SW US WILL PUSH A FRONT ACROSS THE CWA STARTING MONDAY NIGHT AND CONTINUING INTO TUESDAY. LIFTED INDICES NOT IMPRESSIVE WITH THIS SYSTEM BUT SHOWALTER INDICES MORE FAVORABLE FOR THUNDERSTORMS. THEREFORE...WILL KEEP MENTION OF TRW ON TUESDAY BUT WILL DOWNPLAY SOMEWHAT. IN THE WAKE OF THIS SYSTEM ON WEDNESDAY MAY SEE A FEW SPRINKLES IN WRAPAROUND MOISTURE AND WITH THE PASSAGE OF A SHORT WAVE. ON THURSDAY ANOTHER SHORT WAVE DIVING SE ACROSS THE NORTHERN PLAINS WILL PUSH A SFC TROF ACROSS THE CWA. MRF/AVN BOTH CRANKING OUT LIGHT QPF WITH THIS SYSTEM BUT LAST NIGHT'S MRF SHOWS PRECIP TO BE ALL RAIN AND AVN CRITICAL THICKNESSES WOULD INDICATE SNOW OVER THE NORTHEAST SECTIONS. FOR THIS SYSTEM BOTH THE FMR/MEX GUIDANCE GIVING TEMPS TOO WARM FOR SNOW...SO FOR THIS TIME AROUND WILL MENTION RAIN ONLY FOR THURSDAY. PRECIP FROM THIS SYSTEM WILL END ON FRIDAY AND CRITICAL THICKNESSES INDICATE PRECIP ENDING AS LIGHT SNOW SHOWERS OR FLURRIES. GUIDANCE NOT TOO FAR APART...BUT WILL LEAN TOWARD THE COOLER AVN/FAN SIDE. .PAH...NONE. PACKETT ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1120 AM EST SAT FEB 16 2002 MAIN CONCERN THIS FCST PACKAGE IS THE AMNT OF SHSN THIS AFTN AND TNGT. WV IMAGERY SHOWING A SHRTWV MOV OVR CWA THIS AM. KMQT-88D SHOWING THIS SHRTWV DEPOSITING -SHSN ACRS THE CWA. A LTL STRONGER ACTIVITY IS OVR WI. KINL AM RAOBS SHOWING A DRY LYR NR SFC...AND MOIST ARND 775MB. SFC ANLYS DEPICTING A LOW CENTER OVR CNTRL LWR MI AND A LARGE RDG STRETCHING ACRS N PLAINS...MAN...INTO HUDSON BAY. A CDFNT REMAINS N OF LK SUPERIOR OVR ONT. RUC/MESOETA ANLYS SHOWING THE WEAK SHRTWV PASSING OVR THE CWA THIS MRNG WILL BE FOLLOWED QUICKLY BY ANOTHER THIS EVE. RUC/MESO-ETA/AVN ALL POINT TO KEEPING THE CDFNT OVR LK SUPERIOR THIS AFTN BEFORE SLIDING IT OFF TO THE E WITH THE APPROACH OF THE RDG. LAKE-850MB DELTA-T'S WILL INCR TO 16C ACRS N LK SUPERIOR. LOW LVL WNDS CONVRGNC WILL BE MARGINAL...BUT ENOUGH TO CONT LES ACRS CWA. ETA FCST SOUNDING DATA INDC BASE OF INVRSN ARND 900MB (2K FT). CAA WILL BRING THE INVRSN UP TO 500MB (3.1K FT). CYC FLOW AHEAD OF N PLAINS RDG WILL KEEP WNDS OUT OF THE N THIS AFTN. 850-700MB Q-VEC SHOWING MAINLY DVRGNC ACRS CWA THIS AFTN AND 280K ISENTROPIC ANLYS DEPICT SUBSIDENCE. ONLY SOURCE OF LIFT COMES FM LOW LVL (925MB) WND CNVRGENCE. HOWEVER...IT IS WEAK. AVN A LTL STRONGER WITH THIS LES EVENT...DEPICTING DELTA-T'S ARND 17C AND SOME BLYR WND DIVERGENCE BY 00Z SUN. MESO-ETA/RUC SUPPORTS ONLY 1 TO 2 INCHES THIS AFTN...WHEREAS...AVN SUG 2 TO 4 INCHES. A COMPROMISE OF 1 TO 3 INCHES STILL LOOK REASON FOR LES PRONE AREAS OF E U.P. THUS WILL KEEP THE ADVISORY GOING. AVN INCR DELTA-T'S BY MIDNGT TO AROUND 19C ...HOWEVER...SHOW A LOSS OF LOW LVL CONVRNGNC. AVN SOUNDING FCST SHOWING NR SATURATION BLO 850MB THU 06Z. SFC RDG WILL MOV INTO W LK SUPERIOR BY SR...DRYING OUT THE LOW LVLS. MESO-ETA DEPICTING A LTL WRMR AT 850MB. WEAK 925MB WND CNVRGNC CONT OVR E LK SUPERIOR TIL 06Z. LTL STRONG SHRTWV ENERGY WILL MOV ACRS CWA OVRNGT. ISENTROPIC ANLYS SHOWING MAINLY SUBSIDENCE. Q-VEC HAS ONLY WEAK CONVGNC BY 12Z. ALL IN ALL IT APPEARS THAT LES WILL CONT TIL MIDNGT...BUT TAPER OFF CONSIDERABLY BY SR. 1 TO 3 INCHES POSSIBLE THIS EVE OVR E CWA. LES WILL TAPER TO FLURIES WHEN THE SFC RDG MOV ACRS CWA SUN MRNG AS WNDS WILL BCM LGT AND VARIABLE. WILL KEEP LES GOING FOR THIS EVE. LES WILL END AS WNDS VEERING S. AVN/ETA SHOWING WAA ABV 850MB...WILL ALSO BRING SOME SUNSHINE TO THE U.P. ON SUN. TEMPS SHOULD REBOUND NICELY TO ARND 30 ON SUN. .MQT...LES ADVY THIS AFTN/TNGT MIZ005-006. DLG mi SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1104 AM EST SAT FEB 16 2002 THE SURFACE COLD FRONT CURRENTLY EXTENDS FROM CENTRAL LAKE HURON TO SOUTHERN LAKE MICHIGAN...CROSSING CENTRAL LOWER MICHIGAN. THE WATER VAPOR LOOP SHOWS A POTENT SHORT WAVE TROUGH OVER THE WISCONSIN/ILLINOIS BORDER. LIFT AHEAD OF THIS SHORT WAVE AND ASSOCIATED COLD FRONT HAS LED TO AREAS OF SNOWFALL ACROSS SOUTHERN LOWER MICHIGAN. LOW LEVEL FRONTOGENETICAL FORCING AND MID LEVEL DEFORMATION HAS ALLOWED THE SNOWFALL TO BE ORIENTED IN A BANDED STRUCTURE ACROSS THE FORECAST AREA THIS MORNING...WITH THE HEAVIEST SNOWFALL BETWEEN FLINT AND THE TRI CITIES...WITH MOST OF METRO DETROIT SEEING A BREAK IN THE PRECIPITATION DURING THE LATE MORNING HOURS. PRECIP COVERAGE ON KGRR RADAR HOWEVER HAS ALREADY INCREASED AS THE SHORT WAVE TO THE WEST HEADS SOUTHEAST. THIS WILL BRING ANOTHER ROUND OF SNOWFALL EARLY THIS AFTERNOON. THE 12Z MESO ETA AND LATEST RUC HAVE PICKED UP ON THE FASTER PROGRESSION OF THE SURFACE AND UPPER LEVEL FEATURES. COLD FRONT IS PROGGED TO SWING THROUGH THE AREA THE AFTERNOON...REACHING DETROIT BY 21Z...WITH THE SHORT WAVE PROGGED TO SWING INTO CENTRAL INDIANA BY THIS TIME. FORCING SHOULD THUS DIMINISH FROM NORTH TO SOUTH DURING THE AFTERNOON. THE 12Z MESO ETA IS PICKING UP ON THE PRECIP IN SW LOWER...AND BRINGS IT ACROSS THE 1-96 AND 1-69 CORRIDORS EARLY THIS AFTERNOON. WILL LIKELY SEE ANOTHER INCH IN THESE AREAS BEFORE SNOWFALL TAPERS OFF MID AFTERNOON. WITH FRONT MOVING THROUGH...TEMPS SHOULD NOT STRAY FAR FROM CURRENT READINGS. .DTX...NONE. CONSIDINE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 251 AM EST SUN FEB 17 2002 SHORT TERM DISCUSSION... FCST PROBLEM IS DEALING WITH REMAINING LES THIS MORNING AND TEMPS TODAY. LATEST 88D/S FROM AROUND LM SHOWING A CONVERGENT AREA OVR MID LAKE IN ASSOCIATION WITH FINAL S/W PIVOTING THROUGH BACK SIDE OF UPPER TROF. RESIDUAL SYNOPTIC MOISTURE COUPLED WITH DELTA T VALUES AROUND 14C AND LONG NW FETCH YIELDING A DECENT SNOW BAND OVR MID LAKE THAT IS TRYING TO BECOME SINGLE BAND AS SFC WIND FIELD IS BECOMING CONVERGENT. FCST PROBLEM IS WHERE WILL THIS AREA OF SNOW GO AND HOW LONG WILL IT LAST. LATEST RUC NOT HANDLING AREA WELL AND 00Z MESOETA GENERATES SOME H8 UPWARD MOTION BTWN 09Z AND 15Z OVR SRN LM. WL CONT WITH SCT SNOW SHOWER WORDING FOR THIS MORNING IN COUNTIES NEAREST LAKE. WITH FLOW BECOMING MORE NRLY...BULK OF THIS BAND WILL BE CONFINED TO WRN BERRIEN...WRN ST. JOE AND LAPORTE COUNTIES. WITH SYNOPTIC MOISTURE QUICKLY DRYING AND BANDS NOT SETTING UP IN ANY SINGLE LOCATION...EXPECT AMOUNTS TO REMAIN BLO AN INCH. BUFKIT INDICATES INVERSION TO FINALLY CRASH AFTER 15Z WITH GD DRYING AND SUBSIDENCE. EXPECT SNOW TO END RATHER QUICKLY AFTER MID MORNING AS S/W EXITS REGION. SFC RIDGE MOVES IN FOR TONIGHT AND CLR SKIES AND LIGHT WINDS WILL ALLOW A GD DROP IN TEMPS. WAA AT H8 BUT THIS SHLD BE CUT OFF FM SFC WITH INVERSION. STRONG SW FLOW MONDAY TO KICK WINDS UP AND WARM TEMPS WELL INTO 40S. BOTH AVN AND ETA INDICATE STRONG H8 JET OF 55KT MOVING INTO WRN AREAS MON NIGHT. WL ADD LOW CHC POP FOR THIS BUT WOULD NOT BE SURPRISED TO SEE THIS JET MORE INTO NRN IL AS S/W DIGS AND LOW LEVEL FLOW BACKS. EXTENDED DISCUSSION... UNCERTAINTY IN MEDIUM RANGE MODELS FOR UPCOMING WEEK. STRENGTH AND TIMING OF S/W TROFS DIFFICULT. WL CONT WITH CURRENT FCST. .IWX...NONE. LASHLEY/SKIP in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 AM EST SUN FEB 17 2002 00Z RAOBS/LATEST WV LOOP AND RUC ANAL SHOW ERN TROF DOWNSTREAM OF SLOWLY PROGRESSIVE UPR RDG IN THE PLAINS. VIGOROUS SHRTWV DIGGING SE THRU THE LWR LKS ATTM HAS DRIVEN COLDER AIR S OVR LK SUP...WITH H85 TEMPS AS LO AS -16C OVR LK SUP. NCEP DISCUSSION INDICATES MODELS HAVE UNDERDONE STRENGTH OF UPR JET ASSOCIATED WITH SHRTWV. COMBINATION OF COLD AIR BLOWING ACRS LK SUP AND LK INDUCED TROF/SFC CNVGC NR THE SRN SHORE OF LK SUP HAS ALLOWED THE DVLPMNT OF NMRS WND PARALLEL LES BANDS IN 350 FLOW DEPICTED ON MQT VWP...WHICH INDICATES INVRN HGT ARND 7K FT MSL. EARLIER EXIT OF COLDER CLDS ASSOCIATED WITH SHRTWV SUGS ACTIVITY IS NOW PURE LES. MOST INTENSE BAND WITH 24-28DBZ RETURNS MOVG FM WRN ALGER INTO ERN MQT COUNTY AT 05Z. BANDS TENDING TO MIGRATE SLOWLY W WITH TIME AS LLVL FLOW TENDING TO VEER MORE NE OVR ERN LK SUP... RESULTING IN OBSVD CLD DISSIPATION ACRS ERN LK SUP IN DOWNSLOPE FLOW OFF SRN ONTARIO. BANDS OVR WRN LK SUP LOOK LESS IMPRESSIVE THAN OVR THE E WITH CLOSER PROXIMITY TO DRIER AIR IN ONTARIO AND SHORTER FETCH IN NLY FLOW LIMITING DESTABILIZATION. DWPTS FALL BLO ZERO IN ONTARIO...AND 00Z YPL SDNG SHOWS INVRN DOWN TO H9 UNDER RDG STRETCHING FM ONTARIO INTO THE CNTRL PLAINS. 100M H5 HGT RISES BTWN 12Z AND 00Z AHD OF SHRTWV RDG NR LK WINNIPEG AND NVA IN WAKE OF DIGGING SHRTWV. SFC-H7 WAD ON BACK SIDE OF THIS RDG ALSO CONTRIBUTING TO HGT RISES/OBSVD PRES FALLS IN CNTRL CAN. ANOTHER SHRTWV COMING ASHORE IN CA. LES BANDS BEGINNING TO DIMINISH AS ZONE ISSUANCE APRCHS AT 09Z. MAIN FCST CONCERNS THIS PACKAGE ARE LES/CLD TRENDS TNGT...TEMPS AND WNDS TNGT...THEN IMPACT OF APRCHG SYS FM CA MON-TUE. FOR TDAY...MODELS SHOW STRG H5 NVA/H7 DVM AHD OF PROGRESSIVE RDG RESULTING IN FCST NRLY 120M H5 HGT RISE OVR CWA TDAY WITH INVRN HGT LWRG AOB 3K FT THIS MRNG. SFC RDG PROGGED TO SHIFT ESE TO THE CNTRL LKS BY 00Z MON...WITH A FAIRLY STRG SWLY GRADIENT FLOW DVLPG OVR THE WRN HALF OF FA BY END OF DAY AND ADVCTG COLD AIR SLOWLY E. MODELS FAIRLY CONSISTENT ON SHIFTING COLD AIR E...H85 TEMPS FCST TO INCRS TO -1C AT IWD TO -8C AT ANJ BY 00Z MON. BUT SINCE UPR JET ASSOCIATED WITH SHRTWV NOW DIGGING THRU LKS STRGR THAN ANALYZD BY MODELS...COLD AIR MAY BE MORE RESILIENT AS LO PRES DVLPMNT TO E MAY BE MORE INTENSE AND BLOCK EWD PROGRESSION A BIT MORE THAN FCST. XPCT LK CLDS/SHSN TO LINGER THIS MRNG NR LK SUP...ESPECIALLY OVR ERN MQT/WRN ALGER WHERE ETA SHOWS PERSISTENT H925 CNVGC THRU 15Z. HOWEVER... SINCE RADAR TRENDS SHOW SHSN DIMINISHING AND H925 CNVGC FCST TO WEAKEN STEADILY AFTR 09Z WITH RISING PRES...WL ALLOW LES ADVY TO EXPIRE. ONCE FLOW TURNS TO SW...XPCT LK CLD/SHSN TO DSPT. A LTL CONCERNED ETA FCST SNDGS INDICATE LLVL MSTR WL BE TRAPPED BLO INVRN ARND 2K FT MSL IN WEAK H925 CNVGC OVR NCNTRL ZNS MUCH OF DAY WITH SHARPER UPR JET...BUT WL MAINTAIN TREND TOWARD INCRSG SUN THIS AFTN WITH STRGR OFFSHORE FLOW DVLPG AFTR 18Z. HAVE LWRD FCST MAX A BIT CLOSER TO MOS FCST BASED ON ETA FCST SDNGS SHOWING STRG INVRN ABV H9 TEMP HARD PRESSED TO REACH -8C EVEN AT IWD LATE IN THE DAY. HOWEVER...ARRIVAL OF STRGR PRES GRADIENT OVR THE W WL ALLOW MORE MIXING ABV H9 AND HIER TEMPS. AVN/ETA SHOW WEAK SHRTWVS PRESSING E ACRS SRN CAN FLATTENING UPR RDG OVR THE LKS TNGT WITH INCRSG ACYC SWLY GRADIENT FLOW. FCST SNGS SHOW VERY DRY MID LVLS...SO XPCT ONLY PATCHY HIGH CLOUDS IN ADVANCE OF SHRTWVS. MIN TEMPS OVR THE ERN ZNS WL BE TRICKY AS EARLY RADIATIONAL COOLING MAY SET UP AN INVRN EARLY THAT IS MORE RESILIENT TO MIXING ONCE THE STRGR PRES GRADIENT AND HI CLDS MOVE IN...ESPECIALLY IF PROGRESSION OF WHOLE PATTERN IS SLOWED BY DEEPENING TROF TO THE E. WL MAINTAIN THE GOING WIDE SPREAD IN FCST MINS HERE WITH THE LO RANGE OF FCST CLOSER TO LWR FWC FCST TO ACCOUNT FOR PLACES THAT CAN DECOUPLE EARLY. MENTIONED RISING TEMPS LATE AS ETA SHOWS WNDS AT 1K FT INCRSG TO 35 TO 40 KNOTS OVRNGT. OVR THE W...ARRIVAL OF HIER WND/HI CLDS WL BE EARLIER...SO RELATIVELY LTL DIURNAL TEMP DROP WITH LESS SPRD IN MIN TEMPS. HIER AVN MOS FCST LOOKS RSNBL HERE. ATTENTION ON MON TURNS TO APRCH OF SHRTWV NOW COMING ASHORE IN CA. AVN STILL MOST AGGRESSIVE AT PUNCHING PCPN INTO THE CWA LATE IN THE DAY. BUT WITH TENDENCY FOR STRGR UPR JET TO AMPLIFY TROF OVR THE E MORE THAN MODELS FCST AND DRY ANTECEDENT AIRMASS...FAVOR SLOWER ETA/CAN FCST ARRIVAL OF PCPN UNTIL MON NGT. SO HAVE REMOVED POPS FM ALL ZNS ON MON. ETA FCST RH ON 305K ISENTROPIC SFC (ARND H5) INCRSG ABV 70 PCT ONLY DURG THE AFTN WITH DRY AIR HANGING IN BLO...SO HAVE MENTIONED SOME EARLY SUNSHINE FADING BEHIND INCRSG HI CLDS AFTR NOON. TEMPS WL START THE DAY ON THE HI SIDE. WITH FAIRLY TIGHT GRADIENT FLOW AND JUST FILTERED SUNSHINE TO PROMOTE MIXING...HAVE OPTED TO FCST MAX TEMPS ABV MOS GUIDANCE AS H85 TEMPS FCST TO RISE TO ARND 2C DURG THE DAY. ETA FCST SDNGS SUG MAX TEMP OF 46 AT IWD...THINK THIS TOO HI BUT THAT LO 40S RSNBL THERE. PLACES THAT DOWNSLOPE WITH SW FLOW WL ALSO SEE READINGS GOING ABV MOS GUIDANCE...BUT COOLING OFF LK MI WL RETARD WRMG IN THE E. UPR TROF PROGGED TO SHIFT INTO THE CNTRL PLAINS MON NGT...WITH SFC LO MOVG TO NEAR MKC BY 12Z TUE. INCRSG SWLY FLOW AHD OF TROF...WITH AVN AND ETA SHOWING SSW H85 WND INCRSG NR 50 KTS BY MON NGT OVR THE MID MS VALLEY...WL OPEN GLFMEX MSTR. ETA SHOWS PW IN THE NW LKS INCRSG OVR 0.60 INCHES DURG MON NGT...AND FCST SDNGS SHOW DEEP SATURATION ACHIEVED OVR THE ENTIRE CWA OVRNGT. ETA INDICATES UPR DVGC/DPVA AHD OF SHRTWV LIFTING NE FM THE MAIN TROF AND IN RRQ OF 90KT H3 JET IN ONTARIO THAT FORMS IN CONFLUENT FLOW BTWN RDG AHD OF PLAINS SHRTWV AND BASE OF TROF OVR HUDSON BAY ENHANCING LIFT. FOCUS FOR PCPN SHUD BE LLVL CNVGC ALG INVERTED TROF THAT DVLPS OVR CWA... WITH PCPN FAVORED ON COLD SIDE OF THIS TROF. LOOKS LIKE A MIXED PCPN EVENT AT LEAST AT THE ONSET WITH WARM AIR FM THE PRIOR DAY'S HTG AND SFC DWPTS RISING TOWARD 30 FVRG AT LEAST SOME RA. FCST SDNGS OF RATHER UNSTABLE LAPSE RATE BEFORE PCPN ARRIVES WITH LACK OF INVRN REDUCE CHC OF FZRA OR PL...SO JUST A DETERMINATION OF RA VS SN. AS THE SFC HI PRES IN CAN UNDER THE UPR CONFLUENCE BUILDS ON TUE... LLVL COLD AIR APPEARS POISED TO OOZE INTO CWA AS INVERTED TROF PRESSES SLOWLY SE UNDER THE WEIGHT OF THIS COLD AIR. MORE EFFICIENT EVAP COOLING ABV THE NR SFC LYR WL ALSO AID IN THE GRDL CHG OF PCPN TOWARD ALL SN BY LATE MON NGT AND ON TUE BEFORE ARRIVAL OF DRY AIR FM THE NW DIMINISHES THE PCPN. COORDINATED WITH GRB/APX. .MQT...NONE. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 330 AM CST SUN FEB 17 2002 FORECAST FOCUS ON HIGH TEMPERATURES FOR TODAY AND APPROACHING STORM FOR EARLY IN THE WEEK. IN THE SHORT TERM...LINGERING BAND OF CLOUDS ALONG LAKE FRONT SHOULD NOT LAST MUCH INTO EARLY MORNING HOURS AS ETA/AVN/NGM/RUC LOW LEVEL MOISTURE PROGS REPLACE MOIST AIRMASS WITH MUCH DRIER AIR AFTER 12Z. IN ADDITION PROGS MORE INSISTENT THAN 24 HOURS AGO WITH MID LEVEL DRYING AND DOWNWARD VERTICAL MOTION FIELDS. SO WILL STILL GO WITH SUNNY FORECAST FOR TODAY. AMPLE SUNSHINE TO NEUTRALIZE COLD AIR ADVECTION AND WITH LACK OF SNOW COVER...WILL GO ABOVE GUIDANCE NUMBERS FOR HIGHS TODAY. IN THE FAR TERM...AFTER A QUIET NIGHT TONIGHT...ATTENTION TURNS TO SYSTEM APPROACHING FROM THE WEST. NGM ODD PROG OUT AT THE MOMENT AS IT DEVELOPS SURFACE LOW OVER SOUTHERN SOUTH DAKOTA BY MONDAY EVENING...WHILE ETA/AVN FAVOR WESTERN KANSAS. REGARDLESS...AT THIS TIME ETA/AVN PROGS AND TIME CROSS SECTIONS STILL POINT TO MONDAY NIGHT AS EARLIEST ARRIVAL TIME OF PRECIPITATION. 1000/500 MILLIBAR THICKNESS AND 850 MILLIBAR PROGS MORE THAN WARM ENOUGH TO KEEP RAIN ONLY IN FORECAST WITH APPROACH OF SYSTEM. SPC DAY 2 FORECAST PUTS CWA IN GENERAL THUNDER FOR MONDAY NIGHT. LI PROGS FAVOR AN AXIS MORE WEST OF CWA...SO WILL NOT MENTION THUNDER FOR NOW. IN THE FAR FAR TERM...AVN PROG TAKES SYSTEM ACROSS WISCONSIN/ILLINOIS BORDER TUESDAY NIGHT AND EARLY WEDNESDAY AS IT DEEPENS LOW. 1000/500 MILLIBAR THICKNESS PROGS CONTINUE TO INDICATE MAINLY RAIN AND SOME WET SNOW FOR CWA. BUT WITH INTENSIFICATION OF SYSTEM THIS MAY BE OVERDONE AS EXPECT DYNAMIC COOLING TO TAKE PLACE EARLIER. SO THIS SYSTEM BEARS WATCHING EVEN FOR SOUTHERN WISCONSIN. .MKX...NONE. 0...0.../.../...0.../ $$ ZAJDEL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 1014 AM EST SUN FEB 17 2002 DRY HIGH PRESSURE CONTINUES TO DOMINATE. SOME LEE TROUGHING IS HELPING TO LESSEN THE PRESSURE GRADIENT AND BELIEVE THE ETA AND RUC ARE CORRECT IN KEEPING WIND BELOW LAKE WIND ADVISORY CRITERIA THIS AFTERNOON. PLAN TO RAISE THIS AFTERNOON/S HIGH TEMPERATURES ONE CATEGORY BASED ON CURRENT READINGS. NO OTHER CHANGES PLANNED. FCSTID = 5 CAE 58 27 57 27 / 0 0 0 0 AGS 59 26 58 26 / 0 0 0 0 SSC 58 27 56 27 / 0 0 0 0 OGB 59 28 58 28 / 0 0 0 0 .CAE... GA...NONE. SC...NONE. sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG, VA 950 AM EST SUN FEB 17 2002 UPPER AIR INOP THRU TUES MORN. MAIN CONCERNS THIS AFTN WITH WIND SPEEDS ACROSS THE RIDGES AND UPSLOPE SNOWFALL AS FINAL S/W ROTATES THRU ARND BASE OF UPR TROF. THIS IMPULSE INDICATED WELL BY SATL PICS WITH NEXT ROUND OF CLDNS/-SHSN MOVG SEWD THRU SRN OH/WVA ATTM. LATEST MESO-ETA QUITE EXPANSIVE WITH PRECIP CVRG ESPCLY SE WVA...WHILE RUC/AVN APR MORE ON TRACK WITH ADTNL AMTS OF ARND AN INCH OR SO AS BEST RH LOOKS TO PASS JUST N THIS AFTN. THUS WILL CONT WITH HIGH CHC POPS SE WVA WITH BUFFER LOW CHC -SHSN IN BTWN THERE AND THE NRV WHERE WILL ONLY HAVE FLURRY MENTION. ELSW...DOWNSLOPE TO TAPER CLDNS BUT WITH VORT APCHG WILL GO GNRLY PRTLY SNY SERN TIER. PROGGED MODEL PRES RISES A BIT WEAK ATTM BUT GIVEN UPSTREAM SUBSIDENCE/CAA AND CURRENT MSAS PRES RISES APCHG PLAN TO CONT NPW WITH AFTN MIXING KICKING IN. WILL ALSO NEED TO WATCH SPOTS ALONG THE BLUE RDG TWD MID AFTN FOR HIGHER SPEEDS OTRW WILL CONT WINDY/BRZY WORDING AND NOT EXPAND ADVSRY ATTM. TEMPS GNRLY ON TRACK WITH RANGE FROM ARND 50 SE PER DOWNSLOPE WARMING TO NEAR 30 SE WVA WHERE CLDNS/SHSN WILL PREVAIL. .RNK... NC...RED FLAG WARNING UNTIL 700 PM FOR ZONES NCZ003>006...NCZ019>020. WIND ADVISORY THIS AFTERNOON FOR ZONES NCZ001>002...NCZ018. VA...RED FLAG WARNING UNTIL 700 PM FOR ZONES VAZ022>024...VAZ032>035...VAZ043>047...VAZ058>059. WIND ADVISORY THIS AFTERNOON FOR ZONE VAZ015. WV...NONE. JH va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO CA 900 AM PST SUN FEB 17 2002 RAINFALL TOTALS SINCE LATE YESTERDAY AFTERNOON GENERALLY RANGED FROM A HALF INCH TO ONE INCH. SOME VALLEY LOCATIONS WELL INLAND SAW LESS THAN A QUARTER INCH WHILE AMOUNTS UP TO AN INCH AND A HALF WERE OBSERVED IN THE SANTA CRUZ MOUNTAINS AND SANTA LUCIA RANGE. WATER VAPOR SATELLITE IMAGERY SHOWS THAT THE UPPER LOW PASSED OVER THE SFO BAY AREA AROUND SUNRISE THIS MORNING. COLD AIR ALOFT WITH THE LOW CENTER BRIEFLY LOWERED SNOW LEVELS TO 2500 FEET IN THE SANTA CRUZ MOUNTAINS AND A COUPLE INCHES OF SNOW ACCUMULATED ATOP MT HAMILTON. RADAR INDICATES SHOWERS ARE DECREASING FROM NW TO SE AND EXPECT MOST SHOWER ACTIVITY TO END BY MIDDAY AS THE UPPER LOW CONTINUES TO MOVE OFF TO THE EAST. A VORT MAX ROTATING AROUND THE BACK SIDE OF THE LOW THIS AFTERNOON MAY TOUCH OFF A FEW SHOWERS THROUGH THE EARLY EVENING HOURS. THE 12Z ETA AND 06Z PACRUC BOTH SHOW SCATTERED LIGHT QPF VALUES ACROSS THE AREA UNTIL ABOUT 03Z. SO WILL KEEP THE EVENING SLIGHT CHANCE POPS IN THE FORECAST FOR NOW. SKIES ARE ALREADY CLEARING IN THE NORTH BAY AND HAVE ISSUED A ZONE UPDATE FOR ZONES 5 AND 65 TO REDUCE FIRST PERIOD POPS THERE. A SHORTWAVE TROUGH NEAR 40N/140W WILL MOVE RAPIDLY EASTWARD DURING THE NEXT 36 HOURS AS A 120 KT UPPER JET TAKES AIM AT NORTHERN CA. WARM ADVECTION PRECEDING THIS UPPER LEVEL FEATURE WILL GENERATE RAINFALL ON THE NORTHERN CA COAST BY MONDAY AFTERNOON...PERHAPS AS FAR SOUTH AS THE BAY AREA. A SERIES OF WAVES WILL MOVE RAPIDLY THROUGH ZONAL FLOW ALOFT AND INTO NORTHERN CA MONDAY NIGHT AND TUESDAY...RESULTING IN PERIODS OF RAIN...LOCALLY HEAVY IN THE NORTH BAY. STS 423 SFO/LVK 721 SJC/MRY 720 DYKEMA .SFO...TDA...SCA...PT ARENA TO PT PIEDRAS BLANCAS AND MRY BAY FOR HAZARDOUS SEAS. ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 230 PM EST SUN FEB 17 2002 .SYNOPSIS... LOW PRESSURE WILL MOVE OUT INTO THE ATLANTIC WELL SOUTH OF THE STATE TONIGHT. THIS SYSTEM WILL PRODUCE VERY LIGHT SNOW OVER SOUTHERN AREAS BEFORE IT MOVE OUT TO SEA. A LARGE AREA OF HIGH PRESSURE WILL BUILD IN FROM THE WEST ON MONDAY. THIS WILL BRING SUNNY SKIES TO THE AREA MONDAY AND TUESDAY. .DISCUSSION... FROM LATEST AVN/ETA LOOKS LIKE MEASURABLE QPF TONIGHT WILL BE CONFINED TO THE SOUTHWEST PORTION OF THE FORECAST AREA. LATEST RUC ALSO SUGGEST THIS AS WELL. WILL SPLIT OFF SOUTHWESTERN ZONES TO ACCOUNT FOR SNOW AND WILL GO WITH ACCUMULATION OF AROUND AN INCH IN THAT AREA. FURTHER TO THE EAST WILL GO WITH LIKELY POPS OF SNOW SHOWERS WITH LITTLE OR NO ACCUMULATION. IN NORTHERN AREAS WILL STAY MOSTLY CLEAR. WILL STAY CLOSE TO MAV GUIDANCE FOR LOW TEMPERATURES. FOR TOMORROW AND TUESDAY WITH LARGE RIDGE OF HIGH PRESSURE BUILDING IN WILL STAY WITH MOSTLY CLEAR SKIES. AS LOW PRESSURE MOVES UP FROM THE SOUTHWEST EXPECT PRECIPITATION TO DEVELOP WEDNESDAY AFTERNOON AS WARM AIR ADVECTION DEVELOPS OVER THE FORECAST AREA. PRECIPITATION SHOULD DEVELOP AS SNOW IN ALL AREAS. HOWEVER BOTH AVN AND CANADIAN GEM SHOWING CRITICAL THICKNESS MOVING NORTH INTO THE CENTRAL PORTION OF THE FORECAST AREA. SO WILL HIGHLIGHT SNOW OR RAIN IN CENTRAL PORTION AND RAIN IN SOUTHERN PORTION OF THE FORECAST AREA FOR WEDNESDAY NIGHT INTO EARLY THURSDAY. FOR LATER THURSDAY WILL GRADUALLY CHANGE PRECIP BACK TO SNOW IN CENTRAL AREAS AS BOTH NEW AVN AND CANADIAN HINTING OF SECONDARY DEVELOPMENT ON COAST LATER THURSDAY. WILL KEEP SNOW OR RAIN IN SOUTHERN MOST AREAS FOR LATE THURSDAY SINCE EVEN WITH SECONDARY DEVELOPMENT...WILL STILL TAKE SOME TIME FOR COLDER AIR TO FILTER INTO SOUTH. KEEPING SCATTERED SNOW SHOWERS IN FORECAST FOR FRIDAY DUE TO INSTABILITY BEHIND DEPARTING LOW. MRF CONTINUES TO DEVELOP LOW OFFSHORE FOR WEEKEND SO WILL KEEP SCATTERED SNOW SHOWERS IN FORECAST INTO SUNDAY. COASTAL WATERS... MAINTAINING GALE TONIGHT THROUGH MONDAY AND MENTION GUSTS TO 45 KT. WINDS SHOULD DIMINISH TO AROUND 25 KT BY LATE ON MONDAY. .CAR...GALE WARNING. MIGNONE me AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 1040 AM CST SUN FEB 17 2002 CIRRUS TO THE WEST HAVING SOMEWHAT OF A HARD TIME OVERCOMING SUBSIDENCE NEAR MID LVL RIDGE ANCHORED OVER MO/AR/LA. THIS IS SEEN WELL BY WARMING OF CIRRUS ON IR SATELLITE IMAGERY. WILL REMOVE PARTLY CLOUDY IN ZONES FOR THIS AFTERNOON AS ANY HIGH CLOUDS THAT DO ARRIVE WILL BE SCATTERED/THIN IN NATURE. LOW LVLS ARE BONE DRY AS INDICATED BY ETA/RUC CROSS-SECTIONS WITH SURFACE DEW PTS IN THE UPPER 20S AND LOWER 30S. MOSTLY SUNNY WEST HALF...SUNNY EAST HALF WILL SUFFICE. TEMPS AND WINDS LOOK FINE. UPDATES OUT SOON. FCSTID = 05/ JAN 64 35 67 49 / 0 0 0 20 MEI 65 31 65 42 / 0 0 0 0 .JAN... AR...NONE. LA...NONE. MS...NONE. ms FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 242 PM CST SUN FEB 17 2002 ...WILL INSERT VALLEY INTO WIND ADVISORY THROUGH THIS EVENING... WINDS ARE GUSTING UP TO 40 MPH ACROSS PORTIONS OF THE RED RIVER IN THE PAST HOUR. NEW RUC INDICATES 925MB WINDS WILL SUSTAIN AROUND 40KT UNTIL AROUND 00Z...COUPLED WITH FAIRLY ADIABATIC LAYER UP TO 925MB AND TIGHT PRESSURE GRADIENT WILL SUSTAIN WINDS IN ADVISORY CRITERIA UNTIL AROUND 00Z. WINDS WILL SUBSIDE THEREAFTER. NPW ALREADY ISSUED...AS WELL AS EARLY ZFP FOR THIS EVENING AND OVERNIGHT. KELLENBENZ -------------------------------------------------------------------- FORECAST CHALLENGE WILL BE TEMPS AND PRECIP CHANCES IN SOUTH MONDAY NIGHT/TUESDAY .OVERVIEW... FAIRLY TIGHT PRESSURE GRADIENT IN PLACE THIS AFTERNOON FROM VALLEY EAST...AS SFC TROUGH PUSHES INTO CENTRAL ND. ONLY SOME CIRRUS SPILLING THROUGH FA...WITH MINIMAL MOISTURE BELOW 500MB. MODELS HAVE COME INTO BETTER AGREEMENT WITH SOUTHERN STREAM WAVE FOR MON NIGHT/TUE...AND WILL SIDE WITH THE ETA WHICH HAS BEEN MOST CONSISTENT OF LATE. .SHORT TERM... BREEZY CONDITIONS WILL PERSIST THIS EVENING FROM VALLEY EAST...BEFORE SFC TROUGH MOVES TO VALLEY AROUND 06Z...THEN INTO EASTERN FA BY 12Z. 500MB FLOW WILL FLATTEN IN WAKE OF SHORTWAVE TONIGHT...BUT WITH DRY COLUMN ONLY EXPECT SOME HIGH CLOUDS TONIGHT. WITH 850MB TEMP RIDGE MOVING INTO FA OVERNIGHT...TEMPS WON/T FALL TOO MUCH AND FOR THE MOST PART BE IN THE LOW 30S. .MONDAY AND TUESDAY... COOL AIR ADVECTION DEVELOPS ABOVE SFC MONDAY...AS WEAK SFC HIGH NOSES DOWN FROM CANADA. EXPECT MOST CLOUDS IN SOUTHERN FA...WHERE LOWEST CONDENSATION PRESSURE DEFICITS WILL BE AHEAD OF SOUTHERN 500MB SHORTWAVE. TEMPS WILL ONCE AGAIN BE WELL ABOVE NORMAL...AND BE WITHIN A FEW DEGREES OF 40 IN ALL LOCATIONS. CLOUDS INCREASE IN EXTREME SOUTH MONDAY NIGHT...WITH WEAK 850-500MB Q VECTOR CONVERGENCE DEVELOPING HERE. WITH WEAK LIFT AND LOWER CONDENSATION PRESSURE DEFICITS FROM 850-700MB...EXPECT A CHANCE FOR LIGHT RAIN CHANGING TO LIGHT SNOW BY MORNING. FURTHER NORTH...DRIER AIR WILL CONTINUE TO FILTER IN FROM NORTH...AND EXPECT ONLY A FEW CLOUDS HERE. ON TUESDAY...SOUTHERN STREAM SFC LOW AND UPPER LOW MOVE INTO SOUTHERN IOWA...WITH DEFORMATION SNOW BAND JUST SOUTH OF FA. WILL LEAVE A LOW POP FOR LIGHT SNOW IN EXTREME SOUTH...WITH AVN/CANADIAN STILL HINTING AT SOME LIGHT QPF HERE. TEMPS WILL CONTINUE WELL ABOVE NORMAL FOR THIS TIME OF YEAR TUESDAY...BUT COOLER THAN PAST DAYS. .TUESDAY NIGHT THROUGH SUNDAY... LOOKS TO BE A LITTLE COOLER TODAY THAN YESTERDAY. AVN SLOWER TO PULL UPPER LOW OUT TO THE EAST...THUS CONTINUOUS NORTHEASTERLY FLOW AND CLOUDS WILL KEEP TEMPERATURES FROM RISING LIKE THE PAST WEEK. THINGS BEGIN TO WARM BACK UP TOWARDS THE END OF THE WEEK...HOWEVER THINGS ARE A LITTLE SLOWER THAN YESTERDAY. THUS TEMPERATURES ON FRIDAY WILL HAVE TO BE TRIMMED BACK. HAVE MY DOUBTS ABOUT PRECIPITATION WITH THIS SYSTEM...HOWEVER WILL TRIM BACK THE MRF REPRESENTATION AND GO WITH ONLY A SLIGHT TO CHANCE ACROSS NORTHEAST SECTIONS OF THE FORECAST AREA. EVERYTHING SHOWS IT WILL BE STARTING OUT AS RAIN...POSSIBLY FZRA IN THE FAR EAST. THEN BIG FRONT COMES THROUGH AND TEMPS COLDER ON SUNDAY AND POSSIBLY EVEN COOLER NEXT WEEK. .FGF...WIND ADVISORY THROUGH THIS EVENING FOR RED RIVER VALLEY. KELLENBENZ/BRAZZELL nd AREA FORECAST DISCUSSION FOR CENTRAL/N-EAST SD AND W-CENTRAL MN NATIONAL WEATHER SERVICE ABERDEEN SD 1035 AM CST SUN FEB 17 2002 WEAK UPPER SHORT WAVE EMBEDDED IN UPPER RIDGE WILL MOVE OVER CWA TODAY. SURFACE SIGNATURE OF UPPER WAVE NOTED ON 15Z SURFACE ANALYSIS WITH SURFACE TROUGH ENTERING WESTERN SOUTH DAKOTA. WINDS LOOK GOOD IN CURRENT FORECAST WITH RUC AND ETA SHOWING STRONG SURFACE PRESSURE GRADIENT BEING MAINTAINED IN EASTERN CWA THIS AFTERNOON. HIGH CLOUDS ARE OVERSPREADING EASTERN CWA AND EXPECT HIGH CLOUDS TO REMAIN FOR AFTERNOON WITH STRONG LOW AND MID LEVEL WARM ADVECTION DOWNSTREAM OF UPPER SHORT WAVE. AVN AND ETA LOW LEVEL THERMAL FIELDS IN GOOD AGREEMENT IN TERMS OF 850 HPA TEMPERATURES BY 00Z THIS EVENING...WITH WESTERN CWA RISING TO 6 DEGREES CELSIUS. CURRENT FORECASTED HIGH TEMPERATURES THIS AFTERNOON LOOK TO BE ON TRACK DESPITE HIGH CLOUDS. ETA 850-500 HPA LAPSE RATES REACH INTO 7.0-7.5 C/KM RANGE THIS AFTERNOON OVER WESTERN HALF OF CWA...WHICH SHOULD ALLOW FOR SOME GOOD MIXING OF WARMER AIR BEING ADVECTED IN AT LOW LEVELS. UPDATED ZONES HAVE BEEN SENT TO ACCOUNT FOR HIGH CLOUDS...AND SLIGHTLY NUDGED UP HIGH TEMPERATURES IN EASTERN CWA. .ABR...NONE. MARSILI sd