AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 339 AM MST TUE DEC 9 2003 .SHORT TERM... (TODAY AND TONIGHT). METEOROLOGICAL CONCERNS IN THE SHORT TERM FOCUS ON WANING PRECIPITATION OVER THE SOUTHEAST PLAINS THIS MORNING AND THEN WINDS AND TEMPERATURES. LATEST SURFACE DATA INDICATE THAT SOME GENERALLY LIGHT SNOW CONTINUING...MAINLY SOUTH OF HIGHWAY 50 TO THE NEW MEXICO BORDER WITH HIGHEST RETURNS CURRENTLY NOTED IN THE VICINITY OF COLORADO CITY AND RYE. ESTIMATE THAT SOME LOCALS AROUND RYE RECEIVED AROUND 10 INCHES OF SNOW WITH THIS PAST SYSTEM. PRECIPITATION INTENSITY HAS BEEN ON A GENERAL DOWNWARD TREND FOR THE PAST HOUR OR TWO. LATEST VERSIONS OF RUC40/MESO-ETA AND SATELLITE OBSERVATIONS INDICATE THAT UPPER LOW WAS MOVING INTO THE TEXAS PANHANDLE EARLY THIS MORNING. MODELS THEN PROJECT UPPER LOW TO PUSH INTO CENTRAL OKLAHOMA BY EARLY THIS AFTERNOON BEFORE ENTERING MISSOURI TONIGHT. FOR SENSIBLE WEATHER...HAVE PAINTED GRIDS/UPCOMING ZONES WITH SOME MORNING SNOW...ESPECIALLY FAR SOUTHEAST PLAINS...OTHERWISE IMPROVING WEATHER CONDITIONS ARE EXPECTED FROM THIS AFTERNOON INTO WEDNESDAY AS TRANSITORY UPPER RIDGE PUSHES ACROSS. EXPECT TEMPERATURES TO RUN BELOW CLIMATOLOGY TODAY AND TONIGHT... ESPECIALLY OVER SNOW COVERED REGIONS. WILL ALSO CONTINUE WITH AREAS OF BLOWING SNOW FOR MAJORITY OF CWFA TODAY AS WIND GUSTS IN EXCESS OF 20 AND EVEN 35 MPH WILL BE NOTED AT TIMES...ESPECIALLY OVER THE FAR EASTERN COUNTIES. .LONG TERM... (WED...MON) ...MORE PRECIP (SNOWS) POSSIBLE FOR ALL AREAS... LONG RANGE GUIDANCE CONTINUES TO PAINT AN ACTIVE PATTERN FOR COLORADO DURING THIS PERIOD. ALTHOUGH THINGS WILL BE PRETTY QUIET DURING THE MIDDLE PART OF THE WEEK...IT APPEARS FRI/EARLY SAT AND LATE SUNDAY/MONDAY SHOULD BE ACTIVE AS FAIRLY DEEP TROUGHS...SIMILAR TO THE ONE THAT JUST WENT BY...ARE FCST TO MOVE ACROSS THE REGION. THIS SHOULD BRING MORE VALUABLE PRECIP TO THE REGION DURING THESE DAYS. DETAILS... WED...WE DID NOT GET MUCH IN THE WAY OF SNOWS ON THE PLAINS WITH SYSTEM THAT JUST WENT BY...AND THE SNOWS WHICH DID FALL SHOULD MELT RATHER QUICKLY IN THE LOWER ELEVATIONS. FOR THIS REASON...TENDED TO BUMP TEMPS UP A FEW DEGREES FOR MAXES ON WED. DISCUSSIONS WITH DDC WX INDICATE THEY MAY SEE SOME HEAVIER SNOWS IN THEIR CWA...SO TEMPS ALONG BORDER HAVE A FAIRLY SHARP GRADIENT ON THIS DATE. A WEAK PERTURBATION IN THE FLOW IS FCST TO COME ACROSS DURING THE AFTERNOON WED...HOWEVER THIS SHOULD HAVE NO SIGNIF RAMIFICATIONS FOR US. MAIN CONCERN WILL BE A WEAK WIND SHIFT AND SOME GUSTY WINDS AS IT COMES ACROSS. WINDS MAY ALSO BE ENHANCED A BIT OVER HIER ELEVATIONS. THURSDAY...I MADE NO CHANGES TO THE FCST FOR THIS DAY EXCEPT TO FINE TUNE POPS HIER MTNS...MAINLY C MTNS. FRIDAY...1ST DEEP TROUGH TO BEGIN AFFECTING WX. WITH CONFID INCREASING WITH SYSTEM...BUMPED POPS UP TO CHANCE CATEGORY FOR SJU AND C MTNS ON THIS DAY. I ALSO COOLED MAXES DOWN A FEW DEGREES. POPS FOR PLAINS FRI AND FRI NIGHT. DECIDED TO LEAVE POPS IN SLIGHT CAT FOR NOW AS MY CONFID REMAINS NEUTRAL FOR NOW. SAT...SYSTEM CLEARING OUT. MAY BE SOME LINGERING POPS IN C MTNS. TEMPS SEASONABLE. SUNDAY...REMOVED POPS THAT WE HAD AS RIDGE POPS IN ADVANCE OF NEXT SYSTEM. MONDAY...ANOTHER DEEP TROUGH FCST TO COME THROUGH. ALL GUIDANCE WAS IN QUITE GOOD AGREEMENT WITH THIS SYSTEM. SLIGHT POPS WILL CONTINUE FOR ALL LOCATIONS. \/HODANISH && .PUB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 910 PM EST TUE DEC 9 2003 .DISCUSSION...CURRENT OBS SHOW TEMP/DEWPT SPREADS 2 DEGREES OR LESS ACROSS MANY AREAS JUST INLAND FROM THE EAST COAST. IN ADDITION... FOG WAS RAPIDLY DEVELOPING WITH VISIBILITY BELOW 1 MILE AT THE JAX AIRPORT AND AT BQK. 00Z JAX SOUNDING INDICATING LOW LEVEL INVERSION BELOW 1 THOUSAND FT BEGINNING WITH NEAR CALM WIND. THE RUC FORECAST SOUNDINGS INDICATE THIS LOW LEVEL INVERSION PERSISTING MOST OF THE NIGHT...HOWEVER BOUNDARY LAYER WINDS INCREASE AND VEER AS DOES CLOUD COVER AFTER 06Z. WILL UPDATE ZONES TO INCLUDE MENTION OF PATCHY DENSE FOG. THINK THERE WILL BE ENOUGH HIGH CLOUDS IN AND OUT TO PREVENT ANY DENSE FOG THAT DOES FORM FROM GETTING WIDESPREAD. WILL ALSO LOWER MIN TEMPS A CATERGORY AS THEY ARE ALREADY BELOW CURRENT FORECAST VALUES AT MANY LOCATIONS. WE WILL MORE THAN LIKELY GET OUR MIN TEMPS AND LOWEST VISIBILITIES AROUND MIDNIGHT WITH RISING TEMPS AND HIGHER VISIBILITIES BY MORNING. && .MARINE... WILL CONTINUE WITH SCA FOR LATE TONIGHT AS STRONG LOW LEVEL JET APPROACHES AHEAD OF STRONG COLD FRONT. BOSTON TECHNIQUE INDICATES POSSIBLE GUSTS TO GALE FORCE WEDNESDAY AND WILL WORD ACCORDINGLY. && .JAX WATCHES/WARNINGS/ADVISORIES... FL...SCA FOR LATE TONIGHT OUT TO 60 NM. GA...SCA FOR LATE TONIGHT OUT TO 60 NM. && $$ PP/JH fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 940 PM CST TUE DEC 9 2003 .EVENING UPDATE... SO FAR THE FORECAST IS ON TRACK. AT 8 PM REPORTS FROM SPOTTERS/CO-OP OBSERVERS/EM'S/NEWS MEDIA/SURFACE OBS PLACE THE RN/SN LINE FROM AROUND VINTON IN BENTON COUNTY TO EAST OF EDGEWOOD ON THE DELAWARE/CLAYTON COUNTY LINE. 00Z ETA/NGM ARE ALMOST IDENTICAL WITH SURFACE LOW TRACK THROUGH 12Z MOVING LOW FROM SW MO TO JUST NE OF KSTL. THE ACTUAL TRACK OF THE LOW MAY BE A LITTLE NW OF THE ETA'S PER THE 00Z RUC TRACK. THE ETA INITIALIZED H8 TEMPS IN CENTRAL IL TOO COOL LEADING TO A WEAKER BAROCLINIC ZONE OVER THE MS VALLEY. IF A MORE NW TRACK VERIFIES THEN THE TRANSITION TO -SN ALONG AND EAST OF THE RIVER WILL BE DELAYED AND SNOW AMOUNTS WILL BE LIGHTER THAN EXPECTED. HOWEVER...TOO CLOSE TO CALL NOW AND WILL LEAVE CURRENT HEADLINES/AMOUNTS INTACT. CURRENTLY IN THE FAR NW AND ADJACENT AREAS OF CENTRAL IA...THE SNOW IS LIGHT AND ONLY A DUSTING HAS BEEN REPORTED SO FAR. ETA QN VECTORS SHOW DEF ZONE REFORMING OVER WESTERN CWA AROUND 06Z. AS THIS EVOLVES...SN WILL INCREASE. EXPECT CHANGE OVER TO SNOW TO REACH CID JUST AFTER 06Z...DBQ AROUND 09Z AND KMLI/KBRL IN THE 11Z TO 13Z TIME FRAME. RAIN AMOUNTS ALONG AND EAST OF THE RIVER SHOULD EXCEED 2 INCHES IN SOME AREAS. A COUPLE OF REPORTS FROM WEST CENTRAL/NORTHWEST ILLINOIS WERE ALREADY IN THE 1 TO 1.5 INCH RANGE. MODELS SHOW OMEGAS CONCENTRATING ALONG AND EAST OF THE RIVER BETWEEN 06Z AND 12Z...WHICH IS SUPPORTED BY CURRENT RADAR TRENDS. HOWEVER...6 HR FFGS ARE IN THE 2.5 TO 3 INCH RANGE...SUGGESTING FLOODING ISSUES WILL BE MINIMAL. ...DLF... && .SYNOPSIS... MODERATE TO HEAVY RAINFALL...WITH EMBEDDED THUNDERSTORMS...HAS OVERSPREAD MUCH OF THE FORECAST AREA THIS AFTERNOON...LIFTING NORTH AHEAD OF A VORT MAX. A DEEPENING SURFACE LOW IS IN SOUTHWEST MISSOURI...WITH A CLOSED 500MB LOW OVER NORTHEAST OKLAHOMA. TEMPERATURES RANGE FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH... WITH MUCH COLDER AIR IN THE UPPER TEENS NOW MOVING INTO NORTHWEST IOWA. && .DISCUSSION... THE PRIMARY FORECAST CONCERN OVER THE NEXT SEVEN DAYS IS IN THE SHORT TERM...WITH A WINTER STORM LIFTING THROUGH OUR AREA TONIGHT AND WEDNESDAY. THICKNESSES INITIALLY ARE QUITE WARM...SO PRECIP TYPE AND CHANGE-OVER TO SNOW WILL BE AN ISSUE. THE SHORT-TERM MODELS AGREE MODERATELY WELL ON BRINGING THE SURFACE LOW TO SOMEWHERE BETWEEN PIA AND JUST NORTH OF STL BY 12Z WEDNESDAY...WITH THE 500MB LOW INTO SOUTHEAST MISSOURI. INITIALLY WARM AIR WRAPPING AROUND THE LOW WILL KEEP 1000-500MB AND 1000-850MB THICKNESSES TOO WARM FOR SNOW. CHANGE-OVER WILL INITIALLY BE TO SLEET OR WET SNOW...FOLLOWED BY A SNOW. FREEZING RAIN MAY OCCUR FOR A SHORT PERIOD OF TIME IN SOME AREAS. SLEET WILL BEGIN FAR NORTHWEST THIS EVENING...CHANGING OVER TO SNOW BY MIDNIGHT. THE RAIN-SLEET-SNOW AREA WILL PROGRESS SOUTHEAST DURING THE NIGHT... WITH SLEET IN THE QUAD CITIES AT DAWN...CHANGING OVER TO SNOW BY 9 AM. THE CHANGE OVER TO SNOW WILL BE MID TO LATE MORNING FURTHER EAST. INITIALLY THE SNOW COMING INTO THE NORTHWEST WILL BY DRIVEN BY DYNAMICS...BUT BY LATE NIGHT...A DEFORMATION ZONE WILL LIFT INTO THE FORECAST AREA...AND REMAIN OVER THE AREA INTO THE AFTERNOON BEFORE LIFTING NORTHEAST. THEREFORE NORTHWEST SECTIONS WILL RECEIVE SNOW BOTH FROM THE INITIAL DYNAMICS AND DEFORMATION...WHILE SOUTHEAST SECTIONS WILL MAINLY DEFORMATION SNOWFALL. IN ADDITION TO WARM THICKNESSES THROUGH THE FIRST HALF OF THE EVENT...WARM WET GROUND CONDITIONS WILL ALSO RETARD SNOWFALL ACCUMULATION. RATIOS SHOULD BE NEAR 10 TO 1 NORTH AND WEST OF CEDAR RAPIDS...BUT WILL GET PROGRESSIVELY LESS MOVING EAST AND SOUTH. A COMPLICATING FEATURE WILL BE WINDS...WHICH WILL PICK UP TO 25 TO 35 MPH DURING THE DAY. BLOWING SNOW WILL BE A PROBLEM NEAR AND NORTHWEST OF A LINE FROM OTTUMWA TO CEDAR RAPIDS TO MANCHESTER...BUT NOT TOO MUCH SOUTH AND EAST DUE TO LOWER RATIOS...I.E. WETTER SNOW. SNOWFALL TOTALS FOR THIS STORM WILL RANGE FROM 4 TO 8 INCHES FAR NORTHWEST TO AN INCH OR LESS SOUTHEAST. CONFIDENCE AT THIS POINT IS STILL NOT HIGH. MANY PLACES MAY VERIFY WITH AMOUNTS CLOSE TO THE LOWER END OF WARNING/ADVISORY CRITERIA...BUT WITH COLDER THAN GUIDANCE TEMPS NOW POURING INTO NORTHWEST IOWA...THE JURY IS STILL OUT. ONE WAY OR THE OTHER...THE WIND WILL MAKE CONDITIONS TREACHEROUS. LOOKING FURTHER AHEAD...FRIDAY AND SATURDAY WILL SEE THE COLDEST TEMPERATURES OF THE SEASON...AS HIGH PRESSURE MOVES IN OVER WHATEVER SNOW COVER WE GET. THERE WILL BE A CHANCE OF SNOW...MIXED WIT RAIN SOUTH...ON SATURDAY AND EARLY SUNDAY...WITH A SHORT WAVE. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER STORM WARNING TONIGHT AND WEDNESDAY FOR BUCHANAN... DELAWARE...DUBUQUE...BENTON...LINN...JONES...IOWA...JOHNSON... KEOKUK...AND WASHINGTON COUNTIES. WINTER WEATHER ADVISORY FOR LATE TONIGHT AND WEDNESDAY FOR THE REST OF EASTERN IOWA. IL...WINTER WEATHER ADVISORY LATE TONIGHT AND WEDNESDAY FOR ALL COUNTIES. MO...WINTER WEATHER ADVISORY LATE TONIGHT AND WEDNESDAY FOR SCOTLAND AND CLARK COUNTIES. && $$ REA il AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DES MOINES IA 230 PM CST TUE DEC 9 2003 .DISCUSSION... MAIN CONCERN IS TIMING OF STORM WITH CHANGE OVER OF PCPN TO ALL SNOW AND WIND DVLPMNT. WILL FAVOR GFS ATTM SINCE MODEL HAS SHOWN BEST PERSISTENCE IN HANDLING OF THIS EVENT. LOOKING AT MODEL SOUNDINGS ANBD THERMAL FEILDS WOULD EXPECT RAIN TO CHANGE QUICKLY TO SNOW WITH LITTLE OR NO FREZZING PCPN. EXPECT SNOW/WIND TO GET GOING THIS AFTN NWRN HALF OF CWA THEN LATE AFTN AND INTO TONIGHT CENTRAL WITH SERN THIRD LAST WITH WARNING TONIGHT INTO WEDNESDAY. BELIEVE LOOKING AT DYNAMICS AND AVAILABLE MOISTURE HAVE UPPED SNOW AMLUNTS MOST LOCATIONS EXCEPT SE WHERE LAST TO CHANGE OVER. BTWN GFS AND RUC20 AMOUNTS IMPRESSIVE. BELEIVE ATTM THAT CHANGEOVER WILL BE RAPIDS AS COOLING ALOFT DRIVES SYSTEM. OMEGA FIELDS AND JET IMPRESSIVE OVER AREA LT AFTN/TNGT. WITH DEEPENING SFC LOW WOULD EXPECT TIGHT GRADIENT AND FAIRLY STRONG WINDS WITH BLOWING/DRIFTING. && .DMX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING THIS AFTN AND TONIGHT NORHT OF A DENISON TO HAMPTON LINE IAZ004>007-015>017-023>026-033>035-044-045- WINTER STORM WARNING LATE THIS AFTERNOON AND TONIGHT NORHT OF A LINE FROM MT AYR TO TAMA. IAZ027-028-036>039-046>050-057>061-070>073-081>083-092>093- WINTER STORM WARNING TONIGHT FROM LAMONI TO MONTEZUMA. IAZ062-074-075-084>086-094>097- && $$ FORSTER ia AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE GOODLAND KS 108 PM MST TUE DEC 9 2003 .DISCUSSION...WILL BE ISSUING AN UPDATE SHORTLY TO REMOVE THE WINTER STORM WARNING. BLOWING SNOW HAS NOT MATERIALIZED AS EXPECTED. GROUND AND AIR TEMPERATURES NEAR TO SLIGHTLY ABOVE FREEZING HAVE MELTED SNOW JUST ENOUGH TO KEEP THE SNOW FROM BLOWING. DESPITE THE 40 KNOT PLUS WINDS ALOFT SHOWN BY THE PROFILERS...THE FULL EXTENT OF THIS WIND NOT MAKING IT TO THE GROUND. THIS LOOKS TO BE THAT THE SUBSIDENCE BEHIND THE EXITING SYSTEM IS NOT STRONG ENOUGH TO MIX IT TO THE GROUND. SURFACE OBSERVATIONS SHOWING SPEEDS TO THE WEST AND NORTHWEST OF OUR FORECAST AREA ARE STARTING TO DECREASE. BY THE TIME THE SUBSIDENCE INCREASES...THE GRADIENT STARTS TO DECREASE AND THE BOUNDARY LAYER IS DECOUPLING. 20 AND 40 KM RUC ARE SHOWING THIS DECREASING TREND AND KEEP THE SPEEDS BELOW WIND ADVISORY CRITERIA. WILL HAVE BREEZY TO WINDY THE REST OF THE DAY. WILL ADJUST CLOUD TRENDS PER SATELLITE. WILL ALSO BE TWEEKING A FEW TEMPERATURES. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1027 PM EST TUE DEC 9 2003 ...ONGOING HEADLINES DUE TO APPROACHING WINTER STORM THE MAIN FORECAST CONCERNS... .DISCUSSION... MAIN 5H LOW OVER THE SRN PLAINS THIS EVENING CONTINUES TO BECOME MORE NEGATIVELY TILTED AS SHOWN BY LATEST WATER VAPOR IMAGERY. 0Z SOUNDINGS DEPICT DECENT 850 MB LOW LEVEL JET ADVECTING ABUNDANT MOISTURE NORTHWARD INTO AREA OF HEAVIER PRECIPITATION CURRENTLY OVER SRN WI TO SW MI. INVERTED SFC TROUGH EXTENDS FROM THE SFC LOW OVER SRN MO INTO THE ERN U.P. WITH GOOD PRESSURE FALLS NOTED ON MSAS DATA SETS. LATEST RUC TAKES SFC LOW INTO CENTRAL IL BY 12Z...WHICH IS IN GOOD AGREEMENT WITH 18Z GFS RUN. NEW ETA SHIFTS SFC LOW MORE TO THE W AND TIGHTENS IT UP FROM EARLIER RUN...WHICH IS MORE REASONABLE CONSIDERING THE NEGATIVELY TILTED 5H SYSTEM. PER THE NEW RUNS...WL SEE BETTER FORCING TO MOVE INTO THE REGION OVERNIGHT AFTER A BRIEF RESPITE EARLY ON WITH INCREASING ISENTROPIC LIFT. THIS REFLECTED BY REGIONAL RADAR DATA AND SATELLITE IMAGERY. FRONTOGENETIC FORCING FROM NEW ETA NOW IN LINE WITH GFS...SHOWING A BULLSEYE OVER THE CENTRAL U.P. DURING THE DAY WED. SFC SNOWFALL REPORTS SINCE 18Z SHOW GENERAL ACCUMULATIONS OF 1 TO 3 INCHES WITH EARLIER SNOW BAND...WITH BRUCE CROSSING REPORTING 5 INCHES. WITH 6 HR QPF FROM GFS SHOWING .25 INCH BETWEEN 12Z AND 18Z AND WITH 850 MB TEMPS FALLING DECENT SNOWS WL OCCUR IN THESE TWO COUNTIES. WOULD NOT NEED THAT MUCH MORE SNOWFALL OVER IRON AND DICKINSON COUNTIES BY 18Z TO REACH WARNING CRITERIA...AND WITH THIS SYSTEM BECOMING MORE IMPRESSIVE WITH TIME...WL BUMP ADVISORY UP FOR THOSE TWO COUNTIES TO A WARNING. WITH KSAW STILL REPORTING RA AT TIMES WHILE THE NWS OFFICE HAS ALL SNOW ATTM...WL ADJUST WORDING OF PRECIP TYPE IN ONGOING FORECASTS TO REFLECT CURRENT CONDITIONS. FURTHER E...WARMER AIR ADVECTING INTO THE ERN U.P. TO PRODUCE MORE RAINFALL EARLY ON UNTIL THE COLDER AIR CAN WORK ITS WAY IN. ETA/GFS 1000-850 MB THICKNESSES SUGGEST PHASE CHANGE TO OCCUR SOMETIME AFTER DAYBREAK. WL UPDATE THESE ZONES AS WELL FOR PRECIP TYPE. && .MQT WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY TONIGHT THROUGH WED MIZ002-009-084. SNOW ADVISORY TONIGHT THROUGH WED MIZ001-003. WINTER STORM WARNING LATE TONIGHT THROUGH WED MIZ010>012 WINTER STORM WARNING LATE TONIGHT THROUGH WED EVENING MIZ004-005-013-014. WINTER STORM WARNING LATE TONIGHT THROUGH WED NIGHT MIZ006-007-085. && $$ RJT mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1045 AM EST TUE DEC 09 2003 .UPDATED... I DID A QUICK FORECAST UPDATE MOSTLY FOR AFTERNOON WORDING. CLEARLY THE RADAR AND SATELLITE TRENDS SHOW COOLING CLOUD TOPS AND AN EXPANDING AREA OF RAIN WITH EMBEDDED THUNDERSTORMS FROM KANSAS TO INDIANA AND OHIO. THE RUC SHOWS THE AREA OF 850 TO 700 MEAN RH OVER 85 PERCENT EXPANDS DRAMATICALLY BETWEEN 15Z AND 21Z...REACHING OUR SOUTHERN CWA BY 21Z. CURRENTLY RADAR SHOWS TWO BAND OF RAIN HEADING NORTH TOWARD MICHIGAN. THESE WILL MOVE INTO THE COUNTIES SOUTH OF INTERSTATE 96 BY 21Z. GIVEN THE HIGH RH AT LOW LEVELS AND MOST LOCATIONS HAVE VISIBILITIES AT OR BELOW 3 MILES... I WENT WITH OCCASIONAL LIGHT RAIN OR DRIZZLE WITH AREAS OF FOG OVER THE S 1/2 CWA AND OCCASIONAL DRIZZLE WITH AREAS OF FOG OVER THE NRN CWA FOR THIS AFTERNOON. AS FOR TEMPERATURES CONSIDERING THE SOUTHEAST TO EAST WINDS AT THE SURFACE AND THAT TEMPERATURES ARE IN THE 30S SOUTH TO NEAR INTERSTATE 80... HIGHS OF 35 TO 40 SEEMED THE WAY TO GO. SO THAT IS WHAT I DID. LATEST MODEL RUN (12Z) OF THE ETA DOES NOT CHANGE MUCH FROM PREVIOUS THINKING. WILL HAVE TO SEE GFS IF THERE ARE CHANGES THERE. IT WOULD SEEM AREAS OF HEAVY RAIN ARE STILL POSSIBLE TONIGHT INTO WEDNESDAY. THE UPDATED ZONES ARE ALREADY SENT. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. && $$ LAURENS MEADE WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 933 PM CST TUE DEC 9 2003 .DISCUSSION... LATEST SURFACE OBSERVATIONS INDICATE THAT THE VISIBILITIES HAVE IMPROVED DURING THE PAST HOUR. TRENDS FROM AREA RADARS ALSO SUGGEST A DECREASING INTENSITY TREND OVER EAST CENTRAL AND SOUTH CENTRAL MINNESOTA. THE LATEST RUC MODEL INDICATES THAT THE SNOW PARAMETERS...MID LEVEL FRONTOGENSIS...RIGHT ENTRANCE REGION OF THE UPPER JET...FAVORABLE TEMPERATURES FOR SNOW GENERATION AND ISENTROPIC OMEGA WILL DECREASE SIGNIFICANTLY OVER SOUTH CENTRAL AND EAST CENTRAL MINNESOTA BETWEEN 06Z AND 09Z. SINCE VISIBILITIES ARE CURRENTLY A MILE OR MORE...THINK SNOW ACCUMULATIONS ARE DIMINISHING SO WILL ALLOW THE WARNING TO EXPIRE AT MIDNIGHT. A QUICK LOOK AT THE INCOMING MESO ETA AND RUC MODELS CONTINUE TO SHOW FORCING THROUGH THE NIGHT OVER WEST CENTRAL WISCONSIN. WITH RADARS STILL SHOWING PRECIPITATION APPROACHING FROM THE SOUTH...WILL STAY THE COURSE WITH THE WARNING TONIGHT OVER OUR WISCONSIN COUNTY WARNING AREA. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING FOR THIS EVENING MNZ060-062-063-066>070-074>078-082>085-091>093- WI...WINTER STORM WARNING FOR TONIGHT...WIZ014>016-023>028- $$ mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 425 AM CST TUE DEC 9 2003 ...WINTER STORM TAKING AIM ON SOUTHERN MINNESOTA AND WESTERN WISCONSIN... .DISCUSSION... VRY BUSY MORNING WITH VRY DIFFICULT FCST AS MY CWA WL BE SPLIT INTO TWO PARTS...ONE GETTING A SIG SNOW EVENT...AND THE OTHER WONDERING WHAT ALL THE FUSS IS. WL BE A HUGE/SHARP DEMARCATION IN THE SNOW FIELD WHEN THIS IS ALL SAID AND DONE...AND TO TRY AND CUT THE COUNTIES FOR THIS GRADIENT NOT AN EASY TASK. MOST OF THIS HAPPENING IN THE FIRST 24 HRS SO ON TO THE GOODS... SNOW PER KFSD/KMPX REALLY TAKING OFF AND EXPLODING NORTHEAST NOW...JUST AS SHOWN IN RUC/META FORCING FIELDS. BASING MOST OF MY FCST ON MID LVL FRONTO FORCING/RIGHT ENTRANCE REGION OF JET...AS THIS SEEMS TO REALLY BE LINING UP WITH THE +SN AXIS THE BEST. SNOW RATES TO RAPIDLY INCREASE THIS MORNING...AND ALREADY HAVE...AS MANY PARAMETERS COMING INTO PLACE FOR A VRY NICE BANDED EVENT. H6 FWF THIS MORNING NOTHING SHORT OF SPECTACULAR...WITH CONV OF FN VECTORS LINING UP EXPECTED SNOW BAND FROM ST. JAMES THRU SERN METRO TO RICE LAKE. IN FAR ERN/SERN CWA...CROSS SECTIONS SHOW CSI POTENTIAL WITH MOIST -EPV SITTING JUST ABOVE STRONG LAYER OMEGA/FRONTO FORCING. THIS AGEOSTROPHIC CIRCULATIONS SHOULD BE ENHANCED ON THE SLANT...AND WITH DENDRITIC TEMPS BECOMING MORE AND MORE FVBLE THRU AFTN...THINK MUCH OF WARNING AREA IS IN FOR GUD SNOWS. AM ACTUALLY PRETTY CONCERNED THAT SOME BAND CUD REALLY PUT DOWN SOME SERIOUS SNOWS GIVEN THE +SN/CSI INGREDIENTS BEING DEPICTED IN HIGHLY SATURATED FRONTO FORCED REGION...AIDED BY SYNOPTIC SCALE LIFT THRU JET. LINEUP OF THESE INGREDIENTS CUD EASILY LEAVE NWRN MSP METRO WITH AN INCH OR TWO...WITH 6-10 IN SERN METRO. CUD BE THAT DRAMATIC GIVEN NARROWNESS OF FORCING. MANY ACCUM METHODS GET THROWN OUT WINDOW WHEN THE DENDRITES GET MAXED IN HIGHLY SATURATED AIRMASS...AND THE POTENTIAL DOES EXIST TODAY. BIG BURST THIS MORNING WITH ROUND ONE OF FRONTO FORCING...THEN PERHAPS A LULL...THEN ROUND 2 SHOULD COME OUT OF IOWA IN WRN WISC LATE AFTN/TONIGHT AS STRONG S/W ENERGY IN SRN STREAM INCREASES FORCING AGAIN. SNOW TOTALS MAY GET A LITTLE OUT OF HAND FM LADYSMITH TO EAU CLAIRE...AND TRIED TO SHOW THIS LINGERING SN EVENT THERE IN GRIDS. WINDS THIS EVE COULD CAUSE BLOWING/DRIFTING ISSUES IN SCNTL...SO KEPT ALL MN CWA WARNINGS INTO EVENING...AND EXTENDED ALL WI WARNINGS INTO OVERNIGHT. ADMITTEDLY REALLY NEVER GOT THE CHANCE TO LOOK SIG BEYOND 36 HOURS. KEPT MUCH OF THAT PORTION OF FCST AS IS. MANY THANKS TO KARX/KDLH FOR COORDINATING THE EARLY UPGRADE OF THE WARNING. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING FOR TODAY AND THIS EVENING MNZ060-062-063-066>070-074>078-082>085-091>093- WI...WINTER STORM WARNING FOR TODAY AND TONIGHT WIZ014>016-023>028- $$ BINAU mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 320 PM CST TUE DEC 9 2003 FORECAST HIGHLIGHTS INCLUDE THE STRONG FRONTAL FORCING TONIGHT AND COLDER TEMPS WEDNESDAY THROUGH FRIDAY. ANOTHER STORM SYSTEM CROSSES THE GULF COAST REGION SATURDAY NIGHT/SUNDAY. .SHORT TERM... SOUTHERLY FLOW HAS BROUGHT SFC DEWPOINTS INTO THE UPPER 50S TO LOWER 60S THIS AFTERNOON MOST IN LINE WITH PREVIOUS AVN/GFS PROGS. COLD FRONT GATHERING MOMENTUM ALONG A KMLC TO KIAH LINE AND SHOULD CROSS THE MS RIVER ABOUT 7-8PM AND REACH THE I-55 CORRIDOR 10PM-MIDN AND THEN ERN MS BY AROUND 3AM. OVERALL...GUIDANCE HAS CONTINUED SUPPORTING 0.75-1.25" RAIN AMOUNTS WITH THE SQUALL LINE/COLD FRONT BY EARLY WEDNESDAY MORNING. SOME LINGERING LIGHT RAIN POSSIBLE THROUGH THE HIGHWAY 82 CORRIDOR WITH WIDESPREAD CLOUD COVER ELSEWHERE BEFORE FINAL CLEARING EARLY THURSDAY. THE MID-LEVEL CLOSED LOW RAPIDLY DEEPENS WHILE CROSSING THE OZARKS TONIGHT AS IT TAKES ON A NEGATIVE TILT ACROSS THE LOWER MS VALLEY. CURRENT TEMP/DEWPOINT REGIME RESULTING IN SBCAPE OF APPROX 400-600 J/KG ALONG AND AHEAD OF THE COLD FRONT WITH LI/S BETWEEN 0 AND -2. ONE THING THAT IS CERTAIN...STRONG DYNAMICS ARE ASSOCIATED WITH THIS DEEPENING SYSTEM...90 KT CYCLONIC CURVED ULJ...50-60 KT LLJ AND 70 KT 500 MB WINDS. SO FAR THE SQUALL LINE HAS BEEN RATHER TAME FROM WRN AR DOWN THE SABINE RIVER TO NEAR KBPT. REF. SPC WW980 FOR AREAS W OF THE MS RIVER. LATEST RUC/META STILL HANGING ON TO 300-500J/KG AS FRONT PUSHES INTO WRN MS THIS EVENING BUT THIS GETS USED UP BEFORE REACHING I-55. THEN A SECONDARY BULGE OF 500-800J/KG OVER SERN MS AFTER MIDNIGHT GETS TAPPED FOR SOMEWHAT OF A BOOSTER TO THE SQUALL LINE THROUGH THOSE AREAS BEFORE 3 AM. DAMAGING WINDS...HAIL AND ISOLATED TORNADOES ARE STILL POSSIBLE WITH THE PASSAGE OF THIS LINE. AT THIS TIME...THE RISK IS LEANING TOWARD THE MINIMAL END OF THE SPECTRUM...ESPECIALLY FOR AREAS EAST OF I-55 AND NORTH OF I-20. MOST LIKELY WIDESPREAD IMPACT WILL BE BURSTS OF HEAVY RAINFALL NEAR 1 INCH AND WINDS OF 40-50 MPH WITH THE LINE. WEDNESDAY WILL BE A RATHER CHILLY DAY WITH CAA ON THE HEELS OF STRONG NORTHWEST FLOW. WILL KEEP TEMPS HOLDING IN THE 40S ALL DAY. IN ADDITION...WITH THE 850MB THERMAL TROUGH PARKED OVER THE REGION...ALSO MAINTAINING MOSTLY CLOUDY SKIES A GOOD PORTION OF THE DAY...CLEARING LATE WEDNESDAY NIGHT/EARLY THURSDAY FROM SW TO NE WHEN ANOTHER FREEZE(27-32F) LIKELY FOR MOST LOCATIONS. THURSDAY SHOULD BE MODERATING DAY WITH DECENT RETURN OF SUNSHINE. && .LONGER TERM... MED RANGE GUIDANCE AGREES ON DRY FRIDAY/FRIDAY NIGHT WITH DIVERGING SOLUTIONS DEVELOPING FOR SATURDAY/SUNDAY. PREFER UKMET/ECMWF SOLUTIONS WITH EVOLUTION OF NEXT STORM SYSTEM(SLOWER/STRONGER SCENARIO) AS GFS GETTING A HABIT OF BEING TOO WEAK/FASTER WITH THE PAST SEVERAL DISTURBANCES. EXPECT A LITTLE FASTER ECMWF VERSION TO DEVELOP SINCE SRN BRANCH UPPER JET PACKING MORE OF A WALLOP THIS GO ROUND THAN CURRENT SYSTEM. MINOR CHANGES TO TAPER OFF RAIN SUNDAY NIGHT A LITTLE QUICKER AND PUSHING FORWARD MAIN TSRA CHANCES TO 06Z-18Z SUNDAY. OTHERWISE...MAINTAINING BELOW AVG TEMPS BEGINNING OF NEXT WEEK WITH A BIT SHORTER TIME SPACING AS NEXT CHC POPS FOR NEXT TUESDAY NIGHT/WEDNESDAY. .PRELIMINARY POINT TEMPS/POPS... JACKSON 45 46 29 51 29 + 2 - 0 0 0 MERIDIAN 46 48 28 52 27 + 3 0 0 0 0 && .JAN WATCHES/WARNING/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ ms AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE FORT WORTH TX 942 PM CST TUE DEC 9 2003 .942 PM DISCUSSION... WE HAVE UPDATED THE ZONES FOR CLOUDS...WHICH ARE DECREASING MORE RAPIDLY THAN IN THE PREVIOUS FORECAST. WE ALSO ARE CONTINUING THE VERY WINDY CONDITIONS...WHICH ARE LARGELY IN RESPONSE TO STRONG DOWNWARD MOTION IN AN AREA OF VERY STRONG WINDS ALOFT...AND RESULTANT VERTICAL MIXING. AS FOR NEXT WEEKEND...THE POSSIBLE SNOW EVENT IS A LOW PROBABILITY EVENT...AND THE MODELS ARE CHANGING RATHER QUICKLY FROM RUN-TO-RUN WITH THE LIFT...THICKNESS VALUES...MOISTURE...ETC. THE 18Z AVN RUN WAS MUCH WEAKER (AND EARLIER) WITH VERTICAL VELOCITIES THAN THE 12Z AVN RUN THAT THE FORECAST WAS BASED UPON. MOREOVER...THE NEW ETA SHOWS A STRONGER AND WETTER SYSTEM THAN THE 18Z AVN...BUT ONE THAT IS SUFFICIENTLY WARM TO PRECLUDE SNOW/SLEET. BECAUSE OF GREAT UNCERTAINTY...WE WILL LEAVE THAT FORECAST AS IS...AND WAIT FOR EVALUATION OF THE OTHER 00Z MODELS AS THEY COME IN. #26 && .AVIATION... MAIN CONCERNS FOR THIS TAF ISSUANCE WILL BE TIMING EROSION OF STRATUS...AND WIND SPEEDS FOR THE NEXT 24 HOURS. LATEST SPLIT CHANNEL SATELLITE LOOP AND 09/23Z SFC OBS INDICATE OVC040/050 ACROSS NORTHERN HALF OF NORTH TEXAS...WITH HIGHER DECKS ACROSS THE SOUTH. GUIDANCE FROM THE RUC40/MESOETA IS IN AGREEMENT ON KEEPING STRATUS ACROSS THE METROPLEX SITES THROUGH 10/06-07Z...FOLLOWED BY A RAPID CLEARING TREND...AS LARGE SCALE SUBSIDENCE STRENGTHENS ACROSS THE REGION. THUS...WILL PATTERN FORECAST IN THIS FASHION...WITH INITIAL CLEARING AT KACT...FOLLOWED BY KFTW...THEN KDFW/KDAL. ANY BREAKS IN STRATUS...CURRENTLY SEEN INVOF KSEP/KGDJ...SHOULD BE TEMPORARY THIS EVENING. AFTER STRATUS CLEARS...SKC WILL PERSIST FOR REMAINDER OF TAF. CONCERNING SFC WINDS...W/NW DIRECTIONS WITH SPEEDS GENERALLY 20G30 KTS THROUGH EARLY MORNING. SPEEDS/GUSTS SHOULD DIMINISH TO 15-18 KTS TOWARD 10/12Z...AND DECREASE FURTHER TO AOB 12 KTS BY END OF FORECAST PERIOD. 65/DD && .PREV DISCUSSION... WIND ADVISORY WILL REMAIN IN EFFECT THROUGH THE NIGHT AS WINDS OF 25 TO 35 MPH CONTINUE ACROSS THE AREA. WINDS HAVE GUSTED OVER 40 MPH AT SEVERAL PLACES TODAY...AND EVEN A GUST TO 45 MPH HERE AT THE OFFICE THIS AFTERNOON. BRIEF PERIOD OF WRAP AROUND WILL BRING AN INCREASE IN CLOUDS CENTRAL/EASTERN ZONES THIS EVENING...BUT CLOUDS WILL DISSIPATE FROM W TO E BY MIDNIGHT. NORTHEAST ZONES MAY STILL SEE A FEW FLURRIES AS SOME SNOW HAS BEEN REPORTED IN SW OK AT ALTUS... HOBART...AND CLINTON. MOST OF THIS ACTIVITY IS DISSIPATING AS SUBSIDENCE ENSUES IN SW QUADRANT OF UPPER LOW. VIGOROUS STORM SYSTEM WILL MOVE INTO SW CONUS BY FRIDAY. THIS STORM SYSTEM HAS BEEN CONSISTENTLY PROGGED TO TAKE A SOUTHERN TRACK ACROSS SOUTHERN TX THROUGH SATURDAY. GFS ENSEMBLES IN CLOSE AGREEMENT WITH TRACK AND ALL INDICATIONS ARE THAT THIS SYSTEM WILL BE COLD AND VERY WET. PARTIAL THICKNESS VALUES SUGGEST A CHANGE TO SNOW/IP/RAIN MIX NORTHWEST OF A GRAHAM TO SHERMAN LINE FRIDAY NIGHT...WITH MIXTURE SPREADING SE TO AN EASTLAND...DALLAS...SULPHUR SPRINGS LINE SATURDAY MORNING. THE TRACK OF THIS SYSTEM APPEARS CLIMATOLOGICALLY FAVORABLE FOR SNOW IN THIS AREA. FURTHERMORE...RESIDUAL DRY AIR FROM TODAY'S SYSTEM WILL HELP KEEP WETBULB TEMPERATURES QUITE LOW OVER THE AREA ALLOWING FOR SIGNIFICANT WETBULB COOLING ONCE PCPN BEGINS. ALTHOUGH WE WILL GET A BRIEF PERIOD OF RETURN LOW-LEVEL SOUTHERLY FLOW...THE SFC WINDS WILL BECOME NORTHEAST BY MID TO LATE EVENING FRIDAY AS SFC LOW TRACKS ACROSS SOUTHERN TEXAS. THIS WILL BEGIN THE DEEP-LAYER COLD ADVECTION WHICH SHOULD ALLOW PCPN TO CHANGE TO SNOW NORTHWEST AFTER MIDNIGHT FRIDAY NIGHT...SPREADING EAST THROUGH SAT MORN. WETBULB TEMPERATURES COMBINED WITH CLOUDS/PCPN/CAA SUGGEST MRF MOS IS TOO HIGH ON TEMPS SAT (PROBABLY TRENDING TOWARD CLIMO) AND WE ARE UNDERCUTTING BY TWO TO THREE CATEGORIES. THIS SYSTEM BEARS WATCHING...BUT WE WILL NOT ISSUE A WINTER STORM OUTLOOK AT THIS TIME. ROBBINS && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 34 52 28 56 / 10 0 0 0 WACO, TX 35 55 31 60 / 0 0 0 0 PARIS, TX 35 48 25 52 / 20 0 0 0 DENTON, TX 33 51 27 54 / 20 0 0 0 MCKINNEY, TX 33 51 27 54 / 20 0 0 0 DALLAS, TX 34 52 28 56 / 10 0 0 0 TERRELL, TX 36 51 29 55 / 10 0 0 0 CORSICANA, TX 37 54 31 59 / 0 0 0 0 TEMPLE, TX 35 57 31 60 / 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FOR TONIGHT FOR ZONES TXZ091>095... TXZ100>107... TXZ115>123... TXZ129>135... TXZ141>148...TXZ156>162...TXZ174>175. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 545 PM CST TUE DEC 9 2003 .AVIATION... MAIN CONCERNS FOR THIS TAF ISSUANCE WILL BE TIMING EROSION OF STRATUS...AND WIND SPEEDS FOR THE NEXT 24 HOURS. LATEST SPLIT CHANNEL SATELLITE LOOP AND 09/23Z SFC OBS INDICATE OVC040/050 ACROSS NORTHERN HALF OF NORTH TEXAS...WITH HIGHER DECKS ACROSS THE SOUTH. GUIDANCE FROM THE RUC40/MESOETA IS IN AGREEMENT ON KEEPING STRATUS ACROSS THE METROPLEX SITES THROUGH 10/06-07Z...FOLLOWED BY A RAPID CLEARING TREND...AS LARGE SCALE SUBSIDENCE STRENGTHENS ACROSS THE REGION. THUS...WILL PATTERN FORECAST IN THIS FASHION...WITH INITIAL CLEARING AT KACT...FOLLOWED BY KFTW...THEN KDFW/KDAL. ANY BREAKS IN STRATUS...CURRENTLY SEEN INVOF KSEP/KGDJ...SHOULD BE TEMPORARY THIS EVENING. AFTER STRATUS CLEARS...SKC WILL PERSIST FOR REMAINDER OF TAF. CONCERNING SFC WINDS...W/NW DIRECTIONS WITH SPEEDS GENERALLY 20G30 KTS THROUGH EARLY MORNING. SPEEDS/GUSTS SHOULD DIMINISH TO 15-18 KTS TOWARD 10/12Z...AND DECREASE FURTHER TO AOB 12 KTS BY END OF FORECAST PERIOD. 65/DD && .PREV DISCUSSION... WIND ADVISORY WILL REMAIN IN EFFECT THROUGH THE NIGHT AS WINDS OF 25 TO 35 MPH CONTINUE ACROSS THE AREA. WINDS HAVE GUSTED OVER 40 MPH AT SEVERAL PLACES TODAY...AND EVEN A GUST TO 45 MPH HERE AT THE OFFICE THIS AFTERNOON. BRIEF PERIOD OF WRAP AROUND WILL BRING AN INCREASE IN CLOUDS CENTRAL/EASTERN ZONES THIS EVENING...BUT CLOUDS WILL DISSIPATE FROM W TO E BY MIDNIGHT. NORTHEAST ZONES MAY STILL SEE A FEW FLURRIES AS SOME SNOW HAS BEEN REPORTED IN SW OK AT ALTUS... HOBART...AND CLINTON. MOST OF THIS ACTIVITY IS DISSIPATING AS SUBSIDENCE ENSUES IN SW QUADRANT OF UPPER LOW. VIGOROUS STORM SYSTEM WILL MOVE INTO SW CONUS BY FRIDAY. THIS STORM SYSTEM HAS BEEN CONSISTENTLY PROGGED TO TAKE A SOUTHERN TRACK ACROSS SOUTHERN TX THROUGH SATURDAY. GFS ENSEMBLES IN CLOSE AGREEMENT WITH TRACK AND ALL INDICATIONS ARE THAT THIS SYSTEM WILL BE COLD AND VERY WET. PARTIAL THICKNESS VALUES SUGGEST A CHANGE TO SNOW/IP/RAIN MIX NORTHWEST OF A GRAHAM TO SHERMAN LINE FRIDAY NIGHT...WITH MIXTURE SPREADING SE TO AN EASTLAND...DALLAS...SULPHUR SPRINGS LINE SATURDAY MORNING. THE TRACK OF THIS SYSTEM APPEARS CLIMATOLOGICALLY FAVORABLE FOR SNOW IN THIS AREA. FURTHERMORE...RESIDUAL DRY AIR FROM TODAY'S SYSTEM WILL HELP KEEP WETBULB TEMPERATURES QUITE LOW OVER THE AREA ALLOWING FOR SIGNIFICANT WETBULB COOLING ONCE PCPN BEGINS. ALTHOUGH WE WILL GET A BRIEF PERIOD OF RETURN LOW-LEVEL SOUTHERLY FLOW...THE SFC WINDS WILL BECOME NORTHEAST BY MID TO LATE EVENING FRIDAY AS SFC LOW TRACKS ACROSS SOUTHERN TEXAS. THIS WILL BEGIN THE DEEP-LAYER COLD ADVECTION WHICH SHOULD ALLOW PCPN TO CHANGE TO SNOW NORTHWEST AFTER MIDNIGHT FRIDAY NIGHT...SPREADING EAST THROUGH SAT MORN. WETBULB TEMPERATURES COMBINED WITH CLOUDS/PCPN/CAA SUGGEST MRF MOS IS TOO HIGH ON TEMPS SAT (PROBABLY TRENDING TOWARD CLIMO) AND WE ARE UNDERCUTTING BY TWO TO THREE CATEGORIES. THIS SYSTEM BEARS WATCHING...BUT WE WILL NOT ISSUE A WINTER STORM OUTLOOK AT THIS TIME. ROBBINS && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 34 52 28 56 / 10 0 0 0 WACO, TX 35 55 31 60 / 0 0 0 0 PARIS, TX 35 48 25 52 / 20 0 0 0 DENTON, TX 33 51 27 54 / 20 0 0 0 MCKINNEY, TX 33 51 27 54 / 20 0 0 0 DALLAS, TX 34 52 28 56 / 10 0 0 0 TERRELL, TX 36 51 29 55 / 10 0 0 0 CORSICANA, TX 37 54 31 59 / 0 0 0 0 TEMPLE, TX 35 57 31 60 / 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FOR TONIGHT FOR ZONES TXZ091>095... TXZ100>107... TXZ115>123... TXZ129>135... TXZ141>148...TXZ156>162...TXZ174>175. && $$ tx SOUTH TEXAS FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1027 AM CST TUE DEC 9 2003 .DISCUSSION...COLD FRONT/DRYLINE MOVING THROUGH THE NORTHWEST PART OF THE FORECAST AREA AT THIS TIME. PRE-FRONTAL STRATUS CONTINUES EAST OF A GEORGE WEST TO AGUILARES LINE AT 16Z. A FEW LINES OF LIGHT SHOWERS CONTINUE OVER THE NORTHEAST ZONES IN WARM AIR ADVECTION REGION BUT MOISTURE TRAPPED BELOW SIGNIFICANT INVERSION INDICATED ON 12Z CRP SOUNDING. FRONT WILL SWEEP EASTWARD TO THE COAST BY 18Z AND INTO THE OFFSHORE WATERS BY 21Z. WINDY AND MUCH DRIER CONDITIONS EXPECTED THIS AFTERNOON WITH LATEST RUC MODEL SHOWING RELATIVE HUMIDITY VALUES BELOW 15 PERCENT OVER THE RIO GRANDE PLAINS AND MUCH OF THE COASTAL BEND. WINDS SHOULD REMAIN JUST BELOW WIND ADVISORY CRITERIA. FOR MARINE...STRONG ONSHORE WINDS LATE THIS MORNING WILL SWITCH TO OFFSHORE THIS AFTERNOON WITH SMALL CRAFT ADVISORIES IN EFFECT. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 80 43 65 40 / 05 00 00 00 VICTORIA 77 38 64 35 / 20 00 00 00 LAREDO 78 42 66 43 / 00 00 00 00 && .CRP...WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING FOR ALL OF SOUTH TEXAS. SMALL CRAFT ADVISORY FOR ALL THE COASTAL WATERS. && $$ 89/TMT tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 900 AM CST TUE DEC 9 2003 .SHORT TERM...VSBL SATL IMAGERY AND SURFACE OBS SHOW THE COLD FRONT PUSHING INTO THE NORTHWESTERN BRO CWA. THE FRONT IS PASSING WITH JUST SOME CLD COVER AND A WIND SHIFT WITH KBRO RADAR SHOWING NO REFLECTIVITY. MESO-ETA AND RUC DATA SHOWS THE COLD FRONT PUSHING OFFSHORE BY MIDDAY. THIS TIMING APPEARS REASONABLE AND IS REFLECTED PRETTY WELL IN THE CURRENT ZFP. WILL ONLY MAKE SOME MINOR ADJUSTMENTS TO THE FIRST PERIOD OF THE ZFP. && .MARINE...AT 8 AM BUOY 020 REPORTED SOUTH WINDS AT 21 KNOTS WITH GUSTS TO 27 KNOTS AND SEAS AT 10 FEET WITH AN 8 SECOND PERIOD. A COLD FRONT APPROACHING DEEP SOUTH TEXAS TODAY WILL RESULT IN SMALL CRAFT CONDITIONS OVER THE GULF WATERS. THE FRONT WILL MOVE ACROSS THE COASTAL WATERS THIS EVENING SHIFTING WINDS FROM THE SOUTH TO THE NORTHWEST. THERE WILL ONLY BE A SLIGHT CHANCE OF A FEW ISOLATED SHOWERS ACCOMPANYING THE FRONTAL BOUNDARY. ONCE THE FRONT PASSES A HIGH PRESSURE SYSTEM WILL BEGIN MOVING ACROSS THE COASTAL WATERS PRODUCING CLEAR TO PARTLY CLOUDY SKIES THROUGH FRIDAY. WINDS AND SEAS WILL BEGIN SUBSIDING WEDNESDAY AS THE PRESSURE GRADIENT BEGINS TO RELAX. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE GULF WATERS AND MAY BE NECESSARY THROUGH WEDNESDAY DUE TO WINDS AND SEAS. && .AVIATION...VFR CONDITIONS ARE BEING REPORTED ACROSS THE REGIONAL AIRPORTS OF DEEP SOUTH TEXAS THIS MORNING. TODAY A COLD FRONT WILL MOVE THROUGH THE CWA RESULTING IN MODERATE SOUTHERLY WINDS SHIFTING TO THE NORTHWEST AFTER THE FRONTAL PASSAGE. VFR CONDITIONS WILL PREVAIL ACROSS THE REGIONAL AERODROMES THE NEXT FEW DAYS. && .PREVIOUS DISCUSSION...FOG MAKING A RETURN APPEARANCE IN NORTHERN COUNTIES TONIGHT...THIS TIME SHOWING UP CLEARLY ON 11-3.9 MICRON INFRARED SATELLITE IMAGERY AS A DARK BLOB EXTENDING SOUTH INTO JIM HOGG AND BROOKS COUNTIES. BKS ONLY DROPPING TO 4SM VSBY SO FAR TONIGHT...WINDS APPEAR TO BE MIXING DOWN ENOUGH TO PREVENT THE DENSE STUFF. BRO SOUNDING REVEALS EXTREMELY DRY LAYER ABOVE INVERSION AT 2500 FEET. TIMING OF THE FRONT/DRYLINE/BOUNDARY REMAINS FAIRLY CONSISTENT...AVN HAS NORTHWEST WIND SHIFT REACHING THE MOUTH OF THE RIO GRANDE BY EARLY AFTERNOON. ONLY A FEW MINOR ADJUSTMENTS NOTED IN MODEL UPDATED TEMPERATURES THROUGH 48 HOURS. FRONTAL EPISODE FOR THE WEEKEND BEGINNING TO TAKE FIRMER SHAPE...GFS HAS STEPPED UP TIMING OF THE WIND SHIFT TO LATE SATURDAY AFTERNOON. && .BRO WATCHES/WARNINGS/ADVISORIES...SCA TODAY GMZ150-155-170-175. && $$ SYNOPTIC/GRIDS...60 AVIATION/MARINE...63 MESO...ABBOTT THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 918 PM CST TUE DEC 9 2003 .UPDATE... RATHER COMPLICATED FORECAST FOR THE REMAINDER OF THE NIGHT AND WEDNESDAY IN DEALING WITH WARM AIR AT THE SURFACE ACROSS THE EASTERN COUNTIES. 02Z SURFACE ANALYSIS SHOWS MAIN LOW PRESSURE CENTER ACROSS SOUTHERN MISSOURI. 00Z ETA PUSHES SURFACE LOW TO JUST SOUTH OF KCHI BY 18Z WEDNESDAY. SURFACE REPORTS ACROSS THE AREA INDICATE RAIN/SNOW LINE RUNNING FROM NEAR KOLZ..THROUGH KLSE TO NEAR KISW. THIS RAIN SLOW LINE HAS BEGUN TO PUSH SOUTHWARD OVER THE PAST HOUR. LAPS SOUNDING SHOWING ISOTHERMAL LAYER NEAR THE SURFACE IN TRANSITION ZONE AND ONCE PRECIPITATION BEGINS...DYNAMIC COOLING COOLS SURFACE LAYER ENOUGH TO SUPPORT ALL SNOW. WE SAW THIS OCCUR JUST IN THE PAST HALF HOUR AT THE AIRPORT HERE IN LA CROSSE. DEEPEST WARM LAYER ACROSS SOUTHWEST WISCONSIN WILL BE LAST TO ERODE AWAY LATER TONIGHT. STILL EXPECT DEFORMATION AREA TO RE-ESTABLISH ITSELF LATER TONIGHT ACROSS THE FORECAST AREA. FN VECTORS CONTINUES TO SHOW POTENTIAL FOR BANDED PRECIPITATION LATER TONIGHT ACROSS THE AREA. THUS WILL KEEP WARNING GOING FOR ENTIRE AREA. ALSO LATEST PROBABILISTIC HEAVY SNOW OUTLOOK FROM HPC CONTINUES TO SHOW A MODERATE RISK FOR HEAVY SNOW ACROSS THE FORECAST AREA. WILL UPDATE ZONES FOR MINOR COSMETIC CHANGES...BASICALLY TO REMOVE THE THUNDER MENTION FROM THE SOUTHWEST WISCONSIN ZONES. .PREV DISCUSSION... .SHORT TERM...THROUGH THURSDAY MAIN FORECAST CONCERN WILL BE THE IMPENDING WINTER STORM AND ITS AFFECT ON THE FORECAST AREA THROUGH WEDNESDAY. DATA ANALYSIS AT 19Z SHOWING STRONG CYCLOGENESIS UNDERWAY ACROSS THE SOUTHERN PLAINS. CONVECTION CONTINUES TO DEVELOP DUE TO THE STRONG FORCING NORTH OF THE SYSTEM. OBSERVATIONS SHOWING A STRENGTHENING BAROCLINIC ZONE OVER THE FORECAST AREA. OBSERVATIONS FROM A KCCY-KLSE-KAIG LINE HAVE HELD STEADY OR COOLED WHILE WARMING IS TAKING PLACE SOUTH OF THIS BOUNDARY. THIS VERY KEY TO THE PRECIPITATION TYPE AND FORECAST SNOWFALL ACCUMULATIONS. WE ARE COMMITTED TO THE WARNINGS AT THIS TIME AND WILL NOT BE LOWERING ANY HEADLINES UNTIL IT BECOMES OBVIOUS THAT THE FORECAST IS WAY OUT OF LINE. 12Z MODEL RUNS OF THE GFS/ETA/20KM DEVELOPMENTAL RUC (DEV RUC) ARE IN REMARKABLE AGREEMENT WITH THE LARGE SCALE FEATURES. THE DETAILS DIFFER AND WILL BE THE FOCUS OF THE FORECAST PROCESS TODAY. ETA/GFS SOLUTIONS ARE SIMILAR. BOTH KEEP THE BULK OF THE Q VECTOR CONVERGENCE SOUTH OF A KOLZ-KDLL LINE. THIS IS CONCERNING IN THAT MUCH OF THE HIGHER LIQUID AMOUNTS WILL BE OVER THE EXTREME SOUTHEASTERN PORTION OF THE FORECAST AREA. THE ETA/RUC MODEL SOUNDINGS AS WELL AS LAPS SHOW THAT MOST OF THE LOWER ATMOSPHERE IS ISOTHERMAL JUST BELOW ZERO...WITH SOME OF THE EXTREME SOUTHERN AREAS SHOWING A NOSE OF WARMTH JUST ABOVE ZERO. THIS WOULD SUGGEST THAT LIGHT PRECIPITATION WILL FALL AS LIQUID AND ANY HEAVIER PRECIPITATION WOULD CAUSE THIS NOSE TO COOL TO ITS WET BULB DIABATICALLY...THUS FALLING AS SNOW. ADDITIONALLY...THE ETA/GFS SOLUTION ALSO HANDLES THE SNOW ASSOCIATED FROM THE DEFORMATION SIMILARLY. THEY MOVE THE INITIAL PRECIPITATION OFF TO THE NORTH...THEN REDEVELOP ANOTHER BAND MUCH FURTHER SOUTH. THE DEV RUC HANDLES THE PRECIPITATION TYPE AS WELL AS THE DEFORMATION BAND DIFFERENTLY THAN THE GFS/ETA SOLUTIONS. IT CHANGES THE FORECAST AREA OVER TO SNOW MUCH SLOWER THAN THE ETA DOES ALONG THE SOUTHEASTERN AREAS MENTIONED ABOVE. IT ALSO RE-ENHANCES THE CURRENT DEFORMATION BAND AS IT MOVES SOUTHEAST WITH THE MAIN SYSTEM. THIS SEEMS MORE PLAUSIBLE. IT ALSO GENERATES SIGNIFICANT ACCUMULATIONS OF GREATER THAN 8 INCHES ACROSS MOST OF THE FORECAST AREA...EVEN OVER THE RAIN AREAS IN THE FAR SOUTHERN COUNTIES. IT LOOKS NOW THAT THE SYSTEM WILL BE EXITING WEDNESDAY AFTERNOON. THIS IS IN AGREEMENT WITH THE 3 MODELS PREVIOUSLY MENTIONED...SO REDUCED PRECIPITATION CHANCES AND SUBSEQUENT ACCUMULATIONS FOR WEDNESDAY NIGHT. OTHERWISE...THE GOING FORECAST LOOKS GOOD. EITHER WAY /ETA AND GFS VS. THE DEV RUC/...I STILL THINK THAT BOTH A HIGH SUCCESS AND BUST POTENTIAL EXISTS. .LONG TERM...THURSDAY THROUGH MONDAY MAIN FORECAST CHALLENGES HERE ARE TEMPERATURES AND TIMING OF NEXT STORM SYSTEM. SNOW COVER AND SURFACE HIGH PRESSURE SHOULD LAY THE FOUNDATION FOR COLD TEMPERATURES. LOWS BELOW ZERO LOOK PROBABLE NOW. GFS MOS GUIDANCE CONTINUES TO TREND DOWNWARD. THINK THAT TEMPERATURES COULD BE CONSIDERABLY LOWER WITH A CLEAR CALM NIGHT. WILL DROP TEMPERATURES AGAIN. NEXT STORM SYSTEM COULD MOVE THROUGH THE FORECAST AREA EARLY NEXT WEEK. ECMWF SUPPORTS THIS TO A DEGREE. BOTH MODELS SUGGEST A MORE ACTIVE PATTERN DEVELOPING...SO THINK THERE IS ENOUGH CONFIDENCE TO INTRODUCE A LOW CHANCE AT THIS TIME. && .ARX...WATCHES/WARNINGS/ADVISORIES... IA...WINTER STORM WARNING TONIGHT...IAZ008-009-018-019 WINTER STORM WARNING THROUGH WEDNESDAY...IAZ010-011-029-030. MN...WINTER STORM WARNING TONIGHT...MNZ079-086>088-094-095. WINTER STORM WARNING THROUGH WEDNESDAY...MNZ096. WI...WINTER STORM WARNING TONIGHT...WIZ032-033 WINTER STORM WARNING THROUGH WEDNESDAY... WIZ017-029-034-041>044-053>055-061. && $$ KRC wi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 839 PM CST TUE DEC 9 2003 .DISCUSSION...FORECAST FOCUS ON APPROACHING WINTER STORM FOR TONIGHT INTO WEDNESDAY. 00Z NGM PROG AND CURRENT RUC PROG IN EXCELLENT AGREEMENT WITH EVOLUTION OF MISSOURI STORM SYSTEM AT THE MOMENT. SURFACE LOW CURRENTLY OVER SOUTH CENTRAL MISSOURI AND FORECAST BY RUC/NGM TO PUSH INTO WEST CENTRAL ILLINOIS BY 12Z WEDNESDAY WITH NGM TAKING LOW OVER NORTHWEST INDIANA BY 18Z WEDNESDAY. 534-540 1000/500 MILLIBAR THICKNESS BAND FROM BOTH RUC/NGM REMAIN MAINLY NORTHWEST OF CWA THROUGH 12Z WEDNESDAY BEFORE BEGINNING TO BEING PULLED SOUTHEASTWARD ACROSS CWA AS SURFACE LOW TRACKS INTO LOWER MICHIGAN. RUC/NGM SNOW PROGS LATCHING ONTO THIS FEATURE TO DEPICT MAIN SNOW BAND WITH THIS STORM. 850 MILLIBAR LOW AND TEMPERATURE GRADIENT LIKEWISE REMAINS FAVORABLE FOR BULK OF PRECIPITATION TO REMAIN AS RAIN BEFORE COOLING ENOUGH FOR TURNOVER TO SNOW AS PER CURRENT FORECAST. THEREFORE WILL ALLOW CURRENT HEADLINES TO REMAIN AND UPDATE FORECAST TO REMOVE EVENING THUNDERSTORM CHANCES. && .MKX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY LATE TONIGHT AND WED ZNS 46..47..51..56>58..62..63..67..68. && $$ TZ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 330 PM CST TUE DEC 9 2003 .SYNOPSIS...MAIN CHGS THIS FCST PKG WL BE TO DELAY THE TIMING OF THE CHG TO ALL SNOW A BIT IN E-C WI. THIS WL REQUIRE HOLDING WINTER WX ADVISORY FOR THE LAKESHORE OFF UNTIL WEDNESDAY. ALL OTHER HEADLINES WL REMAIN THE SAME...THOUGH WL TWEAK SOME SNOWFALL TOTALS. .SHORT TERM...MAJOR WINTER STORM SYSTEM BEARING DOWN ON THE AREA. SFC LOW DEEPENING IN FAR SW MO. AREA OF PCPN IN RRQ OF JET EXITING THE RGN AND IN REGION OF MID-LVL FRONTOGENETIC FORCING CONTD TO MV ACRS THE NW 1/2 OF THE FCST AREA. AMTS HAVE BEEN LGT THUS FAR. SNOW WL CONT DURING THE EVENING ACRS THE NW PART OF THE FCST AREA. FORCING WL WEAKEN A BIT...BUT COOLER AIR FILTERING SWD SHOULD ALLOW MORE OF THE SNOW TO ACCUMULATE. THE 18Z RUC INDICATED SUBSIDENCE OVER THE SE PART OF THE FCST AREA LATE THIS AFTN/EARLY THIS EVENING...AND THAT APPEARED REASONABLE. IT ALSO SHOWED VERY STG UVV/S HEADED NE INTO THE AREA LATE THIS EVENING...AND BY EXTRAPOLATION...AFTER MIDNIGHT. THAT SHOULD SIGNAL THE ARRIVAL OF THE HVY PCPN WITH THE MAIN SYSTEM. STILL NOT VERY CONFIDENT OF PCPN TYPE FCST IN E-C WI. THE OVERALL CONSENSUS OF THE MODELS WAS THAT THE ZERO DEGREE ISOTHERM AT 850 MB WL BE CLOSE TO/INTO THE SE CORNER OF THE FCST AREA LATE TNGT. THAT COMBINED WITH WARMING OF THE BOUNDARY LAYER BY NE FLOW OFF LAKE MICHIGAN SHOULD SAVE THE LAKESHORE FM GETTING A BIG SNOW. TRIED TO WORK SHARP PCPN TYPE/SNOWFALL TOTAL GRADIENT INTO E-C WI. THAT IS THE FCST ITEM THE EVENING SHIFT WL NEED TO MOST CLOSELY MONITOR FOR POSSIBLE ADJUSTMENTS. SNOW WL START TO DIMINISH FM THE W WED AS THE SYSTEM STARTS TO SHEAR EWD. THE 18Z ETA SLOWED THE SYSTEM A BIT AND WAS VERY MUCH IN LINE WITH PREV GFS RUNS. IT INDICATED THAT SIG PCPN WL LINGER IN E-C WI WELL INTO WED AFTN. DON/T WANT TO END THINGS TOO QUICKLY...HOWEVER...BECAUSE WINDS WL INCR AND WITH TEMPS GENERALLY BLO FREEZING...THE POTENTIAL FOR BLOWING AND DRIFTING SNOW MAY SLOW ANY PRECEPTIBLE IMPROVEMENT IN CONDITIONS. ALSO...FALLING TEMPS ALOFT SHOULD GENERATE A DRIER SNOW WITH HIGHER SNOW-TO-WATER RATIOS...WHICH COULD LEAD TO HIGHER SNOWFALL TOTALS DESPITE LOWER QPFS. .LONG TERM...DEPARTING SYSTEM...LAKE EFFECT SNOW AND TEMPERATURES ARE THE MAIN CONCERNS IN THE LONG TERM. AS THE CURRENT STORM SYSTEM MOVES OUT OF THE REGION THE SNOW LOOKS LIKE IT WILL COME TO AN END ON WEDNESDAY NIGHT...EXCEPT IN THE NORTH WHERE LAKE EFFECT SNOW BECOMES A CONCERN WITH COLD 850 MB TEMPERATURES (-14 C OR COLDER) AND FAVORABLE FETCH OVER LAKE SUPERIOR. COLD ADVECTION CONTINUES DURING THE DAY ON THURSDAY BUT WIND DIRECTION STARTS TO BECOME LESS FAVORABLE FOR LAKE EFFECT IN THE NORTH. DURING THE DAYTIME HOURS ON FRIDAY WARM ADVECTION BEGINS AT 850 MB AND WIND DIRECTION IS NOT GOOD FOR LAKE EFFECT. AFTER THE LAKE EFFECT ENDS THE NEXT CHANCE OF PRECIPITATION APPEARS TO BE ON TUESDAY WITH THE ARRIVAL OF SIGNIFICANT MOISTURE...A MID LEVEL TROUGH AND A SURFACE BOUNDARY. MADE SOME MINOR CHANGES TO PREVIOUS FORECAST TEMPERATURES. GENERALLY WENT ON THE COLD SIDE WITH FRESH SNOW ON THE GROUND AND PARTIAL CLEARING WITH HIGH PRESSURE PASSING OVER THE STATE FRIDAY/FRIDAY NIGHT. TEMPERATURES GRADUALLY WARM UP AS SOUTHERLY WINDS PREVIAL AHEAD OF THE NEXT LOW AND ON THE BACK SIDE OF THE DEPARTING HIGH. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING TONIGHT INTO WEDNESDAY WIZ005-010-018- WINTER STORM WARNING TONIGHT AND WEDNESDAY WIZ011>013-019>021-030-031-035>037-045-073-074- WINTER STORM WARNING LATE TONIGHT AND WEDNESDAY WIZ038-039-048-049- WINTER WEATHER ADVISORY WEDNESDAY WIZ022-040-050- && $$ SKOWRONSKI/MG WWW.CRH.NOAA.GOV/GRB wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 230 PM CST TUE DEC 9 2003 .SHORT TERM...THROUGH THURSDAY MAIN FORECAST CONCERN WILL BE THE IMPENDING WINTER STORM AND ITS AFFECT ON THE FORECAST AREA THROUGH WEDNESDAY. DATA ANALYSIS AT 19Z SHOWING STRONG CYCLOGENESIS UNDERWAY ACROSS THE SOUTHERN PLAINS. CONVECTION CONTINUES TO DEVELOP DUE TO THE STRONG FORCING NORTH OF THE SYSTEM. OBSERVATIONS SHOWING A STRENGTHENING BAROCLINIC ZONE OVER THE FORECAST AREA. OBSERVATIONS FROM A KCCY-KLSE-KAIG LINE HAVE HELD STEADY OR COOLED WHILE WARMING IS TAKING PLACE SOUTH OF THIS BOUNDARY. THIS VERY KEY TO THE PRECIPITATION TYPE AND FORECAST SNOWFALL ACCUMULATIONS. WE ARE COMITTED TO THE WARNINGS AT THIS TIME AND WILL NOT BE LOWERING ANY HEADLINES UNTIL IT BECOMES OBVIOUS THAT THE FORECAST IS WAY OUT OF LINE. 12Z MODEL RUNS OF THE GFS/ETA/20KM DEVELOPMENTAL RUC (DEV RUC) ARE IN REMARKABLE AGREEMENT WITH THE LARGE SCALE FEATURES. THE DETAILS DIFFER AND WILL BE THE FOCUS OF THE FORECAST PROCESS TODAY. ETA/GFS SOLUTIONS ARE SIMLAR. BOTH KEEP THE BULK OF THE Q VECTOR CONVERGENCE SOUTH OF A KOLZ-KDLL LINE. THIS IS CONCERNING IN THAT MUCH OF THE HIGHER LIQUID AMOUNTS WILL BE OVER THE EXTREME SOUTHEASTERN PORTION OF THE FORECAST AREA. THE ETA/RUC MODEL SOUNDINGS AS WELL AS LAPS SHOW THAT MOST OF THE LOWER ATMOSPHERE IS ISOTHERMAL JUST BELOW ZERO...WITH SOME OF THE EXTREME SOUTHERN AREAS SHOWING A NOSE OF WARMTH JUST ABOVE ZERO. THIS WOULD SUGGEST THAT LIGHT PRECIPITATION WILL FALL AS LIQUID AND ANY HEAVIER PRECIPITATION WOULD CAUSE THIS NOSE TO COOL TO ITS WET BULB DIABATICALLY...THUS FALLING AS SNOW. ADDITIONALLY...THE ETA/GFS SOLUTION ALSO HANDLES THE SNOW ASSOCIATED FROM THE DEFORMATION SIMULARLY. THEY MOVE THE INITIAL PRECIPITATION OFF TO THE NORTH...THEN REDEVELOP ANOTHER BAND MUCH FURTHER SOUTH. THE DEV RUC HANDLES THE PRECIPITATION TYPE AS WELL AS THE DEFORMATION BAND DIFFERENTLY THAN THE GFS/ETA SOLUTIONS. IT CHANGES THE FORECAST AREA OVER TO SNOW MUCH SLOWER THAN THE ETA DOES ALONG THE SOUTHEASTERN AREAS MENTIONED ABOVE. IT ALSO RE-ENHANCES THE CURRENT DEFORMATION BAND AS IT MOVES SOUTHEAST WITH THE MAIN SYSTEM. THIS SEEMS MORE PLAUSIBLE. IT ALSO GENERATES SIGNIFICANT ACCUMULATIONS OF GREATER THAN 8 INCHES ACROSS MOST OF THE FORECAST AREA...EVEN OVER THE RAIN AREAS IN THE FAR SOUTHERN COUNTIES. IT LOOKS NOW THAT THE SYSTEM WILL BE EXITING WEDNESDAY AFTERNOON. THIS IS IN AGREEMENT WITH THE 3 MODELS PREVIOUSLY MENTIONED...SO REDUCED PRECIPITATION CHANCES AND SUBSEQUENT ACCUMULATIONS FOR WEDNESDAY NIGHT. OTHERWISE...THE GOING FORECAST LOOKS GOOD. EITHER WAY /ETA AND GFS VS. THE DEV RUC/...I STILL THINK THAT BOTH A HIGH SUCCESS AND BUST POTENTIAL EXISTS. .LONG TERM...THURSDAY THROUGH MONDAY MAIN FORECAST CHALLENGES HERE ARE TEMPERATURES AND TIMING OF NEXT STORM SYSTEM. SNOW COVER AND SURFACE HIGH PRESSURE SHOULD LAY THE FOUNDATION FOR COLD TEMPERATURES. LOWS BELOW ZERO LOOK PROBABLE NOW. GFS MOS GUIDANCE CONTINUES TO TREND DOWNWARD. THINK THAT TEMPERATURES COULD BE CONSIDERABLY LOWER WITH A CLEAR CALM NIGHT. WILL DROP TEMPERATURES AGAIN. NEXT STORM SYSTEM COULD MOVE THROUGH THE FORECAST AREA EARLY NEXT WEEK. ECMWF SUPPORTS THIS TO A DEGREE. BOTH MODELS SUGGEST A MORE ACTIVE PATTERN DEVELOPING...SO THINK THERE IS ENOUGH CONFIDENCE TO INTORDUCE A LOW CHANCE AT THIS TIME. && .ARX...WATCHES/WARNINGS/ADVISORIES... IA...WINTER STORM WARNING TONIGHT...IAZ008-009-018-019 WINTER STORM WARNING THROUGH WEDNESDAY...IAZ010-011-029-030. MN...WINTER STORM WARNING TONIGHT...MNZ079-086>088-094-095. WINTER STORM WARNING THROUGH WEDNESDAY...MNZ096. WI...WINTER STORM WARNING TONIGHT...WIZ032-033 WINTER STORM WARNING THROUGH WEDNESDAY... WIZ017-029-034-041>044-053>055-061. && $$ KRC wi AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE ST LOUIS MO 245 AM CST WED DEC 10 2003 CORRECTION TO ADVISORY VALID TIMES .DISCUSSION... FORECAST CHALLENGE DEALS WITH WEATHER ASSOCIATED WITH ONGOING ADVISORY. CURRENT FORECAST HAS GOOD HANDLE ON SITUATION...AND ONLY PLAN MINOR TWEAKS FOR THE REGULAR ISSUANCE. CONTINUE TO FAVOR THE GFS WITH THIS PACKAGE GIVEN IT'S DECENT HANDLING OF SYSTEM SO FAR. SHARP COLD FRONT HAS NOW MOVED INTO CWA...WITH DEEPENING LOW NEAR COU. EXPECT PCPN CHANGEOVER LINE TO MOVE INTO WRN PART OF CWA BY 12Z AND PROGRESS EWD...MAKING IT EAST OF THE MS RIVER BY 18Z AND EXITING CWA BY 21Z. RECENT OBS OF MIXED PCPN OVER WRN MO CONFIRM MESOETA FORECAST SOUNDINGS. RUC ANALYSIS HANDLING BAND OF MDT TO HVY SNOW IN DEFORMATION ZONE WITH SMALL AREA OF CONVECTIVE INSTABILITY. RUC ANALYIS IS DEPICTING THE LOW/MID LEVEL FRONTOGENESIS/CONVERGENCE AND TROWAL STRUCTURE PRETTY WELL...AND RUC/GFS COMBINATION LIFTS THESE FORCING FEATURES QUICKLY NEWD ACROSS GOING ADVISORY AREA. EXPECT A FEW HOURS OF WRN PART OF CWA COULD SEE A FEW HOURS OF DECENT SNOWFALL...BUT ANY MIXED OR FROZEN PCPN AND SOIL TEMPS IN THE LOWER 40S SHOULD LIMIT RESULTING TOTALS. SO WILL NOT CHANGE GOING AMOUNTS...THOUGH MIGHT SEE SOME ACCUMULATING SNOW A LITTLE FARTHER SOUTH WHERE THERE IS STRONG 850MB FRONTOGENESIS ALONG COLD FRONT. FORCING QUICKLY EXITS NRN PART OF CWA BY EARLY THIS AFTN...LEAVING ONLY FLURRIES ACROSS THE AREA BY LATE AFTN. STRONG PRESSURE GRADIENT BEHIND SFC LOW WILL BRING WINDS CLOSE TO ADVISORY CRITERIA...BUT WILL HOLD OFF ON THAT. SFC OBS OVER WRN MO REPORTED SOME BLSN WITH THE STRONG GRADIENT WINDS...AND WILL REFLECT THIS TREND IN WSW AND FORECAST PRODUCTS. WENT WITH THE COOL SIDE OF TEMP GUIDANCE...ESPECIALLY IN AREA WITH SNOW COVER. MADE NO CHANGES TO THE EXTENDED. && .LSX WATCHES/WARNINGS/ADVISORIES... MO...WINTER WEATHER ADVISORY THIS MORNING ALONG AND WEST OF A JEFFERSON CITY...HANNIBAL LINE. IL...WINTER WEATHER ADVISORY THIS MORNING FOR THE UIN AREA. $$ BRITT mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 245 AM CST WED DEC 10 2003 .DISCUSSION... FORECAST CHALLENGE DEALS WITH WEATHER ASSOCIATED WITH ONGOING ADVISORY. CURRENT FORECAST HAS GOOD HANDLE ON SITUATION...AND ONLY PLAN MINOR TWEAKS FOR THE REGULAR ISSUANCE. CONTINUE TO FAVOR THE GFS WITH THIS PACKAGE GIVEN IT'S DECENT HANDLING OF SYSTEM SO FAR. SHARP COLD FRONT HAS NOW MOVED INTO CWA...WITH DEEPENING LOW NEAR COU. EXPECT PCPN CHANGEOVER LINE TO MOVE INTO WRN PART OF CWA BY 12Z AND PROGRESS EWD...MAKING IT EAST OF THE MS RIVER BY 18Z AND EXITING CWA BY 21Z. RECENT OBS OF MIXED PCPN OVER WRN MO CONFIRM MESOETA FORECAST SOUNDINGS. RUC ANALYSIS HANDLING BAND OF MDT TO HVY SNOW IN DEFORMATION ZONE WITH SMALL AREA OF CONVECTIVE INSTABILITY. RUC ANALYIS IS DEPICTING THE LOW/MID LEVEL FRONTOGENESIS/CONVERGENCE AND TROWAL STRUCTURE PRETTY WELL...AND RUC/GFS COMBINATION LIFTS THESE FORCING FEATURES QUICKLY NEWD ACROSS GOING ADVISORY AREA. EXPECT A FEW HOURS OF WRN PART OF CWA COULD SEE A FEW HOURS OF DECENT SNOWFALL...BUT ANY MIXED OR FROZEN PCPN AND SOIL TEMPS IN THE LOWER 40S SHOULD LIMIT RESULTING TOTALS. SO WILL NOT CHANGE GOING AMOUNTS...THOUGH MIGHT SEE SOME ACCUMULATING SNOW A LITTLE FARTHER SOUTH WHERE THERE IS STRONG 850MB FRONTOGENESIS ALONG COLD FRONT. FORCING QUICKLY EXITS NRN PART OF CWA BY EARLY THIS AFTN...LEAVING ONLY FLURRIES ACROSS THE AREA BY LATE AFTN. STRONG PRESSURE GRADIENT BEHIND SFC LOW WILL BRING WINDS CLOSE TO ADVISORY CRITERIA...BUT WILL HOLD OFF ON THAT. SFC OBS OVER WRN MO REPORTED SOME BLSN WITH THE STRONG GRADIENT WINDS...AND WILL REFLECT THIS TREND IN WSW AND FORECAST PRODUCTS. WENT WITH THE COOL SIDE OF TEMP GUIDANCE...ESPECIALLY IN AREA WITH SNOW COVER. MADE NO CHANGES TO THE EXTENDED. && .LSX WATCHES/WARNINGS/ADVISORIES... MO...WINTER WEATHER ADVISORY LATE TONIGHT AND WEDNESDAY MORNING ALONG AND WEST OF A JEFFERSON CITY...HANNIBAL LINE. IL...WINTER WEATHER ADVISORY LATE TONIGHT AND WEDNESDAY MORNING FOR THE UIN AREA. $$ BRITT mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE QUAD CITIES IA IL 700 AM CST WED DEC 10 2003 ***UPDATED*** WARM AIR REALLY WRAPPED UP INTO STORM...MAKING FOR DIFFICULT SNOW FORECAST WITH TIMING OF CHANGEOVER CRITICAL AND SURFACE TEMPS CRITICAL FOR SNOW ACCUMS. RAIN/SNOW LINE NOW JUST EAST OF MONTICELLO...TO IOWA CITY...TO WASHINGTON...TO MEMPHIS MO LINE...AND MOVING SLOWLY EAST. HAVE TRIMMED BACK AMOUNTS MOST LOCATIONS ESPECIALLY ALONG AND EAST OF THE MISSISSIPPI WITH RUC SOUNDINGS DELAYING CHANGEOVER UNTIL BETWEEN 15Z-17Z...AND IN THE FAR EAST AROUND 18Z. DEF ZONE AXIS OF DILITATION SETTING UP ROUGHLY FROM DBQ TO FFL WHERE LIKELY BEST POTENTIAL FOR HIGHER ACCUMS (CURRENT THINKING 2-4 INCHES) BASED ON LITTLE MOVEMENT OF THIS AXIS THIS MORNING WITH DECENT FEED FROM WARM CONVEYOUR BELT...WHERE SNOW COULD BE MODERATE TO POSSIBLY HEAVY FOR A TIME. HAVE RECEIVED REPORTS OF 1 INCH ACCUMS IN INDEPENDENCE AND EDGEWOOD (NORTHERN DELAWARE COUNTY). STRONG WINDS WILL WHIP AROUND FRESH SNOW REDUCING VISIBILITIES ESPECIALLY IN OPEN AREAS. ALSO...COMBINATION OF SNOW...WIND AND FALLING TEMPS WILL ALLOW PUDDLES TO FREEZE THUS RESULTING IN SLICK AND HAZARDOUS CONDITIONS. .SYNOPSIS... SFC LOW INDICATED BY LATEST SFC AND MSAS LOOP PULLING UP JUST NORTHWEST OF THE STL AREA ATTM...AND A BIT DEEPER(CLOSING IN ON 991 MB) THEN LATEST MODEL RUNS. WIDESPREAD RAIN FIELDS FED BY WARM CONVEYOR BELT CONTINUE TO INUNDATE THE SOUTHWEST 2/3'S OF THE CWA... WITH DEEPENING LLVL NORTHERLY FETCH ACRS THE FAR WESTERN AND SOUTHWESTERN CWA SWITCHING THE RAIN TO SNOW AFTER 08Z. && .DISCUSSION... CONCENTRATING ON DEALING WITH THE WINTER STORM AT HAND. WITH SHORT RANGE MODELS SIMILAR IN SWEEPING UPPER LOW UP THE OH RVR VALLEY TODAY AND TONIGHT(GFS PROBABLY CORRECT IN HOLDING ON TO CUT-OFF UPPER FEATURE THE LONGEST)...SFC LOW SHOULD MAKE IT TO EAST CENTRAL IL/NORTHWEST IL BORDER SOUTH OF CHI BY 18Z...AND NORTHEAST INDIANA BY 00Z THU...A TRACK A TOUCH SLOWER AND NORTHWEST OF THE LATEST 00Z RUN GFS TRACK. MSAS INDICATED 3 HR PRESSURE FALLS "LIGHTING THE WAY" TOWARD NORTHEAST IL AND SUGGESTING THIS PATHWAY IN LINE OF LATEST THINKING. REGIONAL 88D LOOPS AND SFC FEATURE TRENDS TELLING THE CONCEPTUAL STORY THAT TIGHTENING DEZ ZONE PRECIP BAND THAT IS OR WILL BE SNOW PULLING OUT OF NORTHWEST AND NORTH CENTRAL MO...AND TAKING AIM AT THE CENTRAL CWA. LOCAL 88D LOOP SHOWS ENHANCED PRECIP BAND ALREADY IN PLACE ACRS THIS AREA IN THE LOCAL CWA AS WELL. LATEST THINKING HAS HEAVIEST SNOW PRODUCING BANDS FED BY WARM AIR CONVEYOR BELT AND WESTERN END OF BEST CONVERGENCE FIELDS AND COLD AIR INTRUSION INTERMINGLING PROCESSES...SETTING UP JUST WEST OF THE MS RVR. WITH FFL AND WASHINGTON IOWA ALREADY SWITCHING OVER AND TAKING ACCOUNT DEF ZONE STILL TO PULL NORTHEAST OUT OF MO...A BAND OF 3-5 INCHES COULD GET LAID OUT FROM AROUND FAIRFEILD...TO EAST OF IOWA CITY...AND TO SOUTHEAST OF THE DBQ VCNTY. WOULD NOT BE SURPRISED IF SOME 6 INCH PLUS AMOUNTS OCCUR IN SOUTHEAST IA AND TO JUST WEST OF THE QUAD CITIES...BUT WILL KEEP HIGH END WINTER WX ADVISORY GOING FOR THESE AREAS. ORIGINAL WARNING AREA NOW LOOKS TO BE ON THE WESTERN FRINGE OF MAIN DEF ZONE SET UP AND WILL BE DOWNGRADED TO AN ADVISORY FOR 1-3 INCHES AND BLOWING SNOW TROUBLES. LOWEST SNOWFALL AMOUNTS TO OCCUR IN THE LAST RAIN-TO-SNOW SWITCH OVER AREAS...GENERALLY WEST CENTRAL IL AND THE FAR EASTERN I-80 CORRIDOR. SOME OF THESE AREAS MAY BE LUCKY TO GET AN INCH. 50 KT PLUS NORTHERLY H85 FEED BUILDING IN FROM THE WEST TODAY BEHIND EXITING BUT BOMBING SYSTEM...ALONG WITH SOME DECENT DOWNWARD MOMENTUM TRANSFER PARAMETERS SEEN ON FCST SOUNDINGS AND LLVL LAPSE RATES... SUGGEST WIND ADVISORY CRITERIA MAY BE MET TODAY. THIS WILL WARRANT WINTER WX ADVISORY TODAY EVEN IN AREAS WITH THE LIGHTEST SNOW ACCUMULATIONS. STILL LOOKS LIKE A CLEAR OUT AND COLD NIGHT AHEAD WITH LOWS GETTING INTO THE TEENS...BUT WINDS SHOULD GREATLY DECREASE ESPECIALLY AFTER MIDNIGHT. A MORE DETAILED AFD WITH LATEST THINKING MAY FOLLOW 4 AM ZONE AND HEADLINE ISSUANCE IF TIME PERMITS. && .LONG TERM...(FRIDAY THROUGH TUESDAY) LITTLE OR NO CHANGES MADE WITH CONTINUING FOCUS ON CURRENT WINTER STORM SITUATION. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER STORM WARNING TODAY DOWNGRADED TO A WINTER WEATHER ADVISORY FOR BUCHANAN...DELAWARE...DUBUQUE...BENTON...LINN...JONES... IOWA...JOHNSON...KEOKUK...AND WASHINGTON COUNTIES. WINTER WEATHER ADVISORY CONTINUES FOR TODAY FOR THE REST OF EASTERN IOWA. IL...WINTER WEATHER ADVISORY TODAY FOR ALL COUNTIES. MO...WINTER WEATHER ADVISORY TODAY FOR SCOTLAND AND CLARK COUNTIES. && $$ 12/05 il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1055 AM EST WED DEC 10 2003 .DISCUSSION... WATER VAPOR IMAGERY AND RUC/ETA SHOWING A CLOSED LOW OVER MIDDLE MISSISSIPPI VALLEY. A RIDGE IS OVER THE NORTHERN HIGH PLAINS. SURFACE ANALYSIS SHOWING A LOW OVER CENTRAL ILLINOIS WITH WARM FRONT STRETCHING NORTHEAST THROUGH MICHIGAN. A COLD FRONT EXTENDS SOUTHEAST THROUGH GEORGIA. Q-VECTOR CONVERGENCE ASSOCIATED WITH THE SHORTWAVE WILL MOVE OVER THE FORECAST AREA TODAY AS THE SHORTWAVE MOVES INTO THE UPPER MISSISSIPPI VALLEY. THE SURFACE LOW WILL WORK NORTH INTO SOUTHWEST MICHIGAN THIS AFTERNOON WHILE THE WARM FRONT EDGES INTO NORTHERN LOWER AND NORTHERN LAKE HURON. LOW LEVEL MOISTURE WILL BE NEAR SATURATION ACROSS THE FORECAST AREA. LOW LEVEL CONVERGENCE WILL CONTINUE TO BE STRONG OVER LAKE SUPERIOR AND ALONG THE LAKE MICHIGAN SHORE. LAKE-850MB DELTA-T'S WILL INCREASE 16C ALONG THE NORTHWEST SHORE OF LAKE SUPERIOR THIS AFTERNOON. WINDS WILL BE OUT OF THE NORTH WHICH WILL HELP GENERATE LAKE EFFECT SNOWS OVER THE NORTHERN U.P. THIS AFTERNOON AND TONIGHT. THE TRAJECTORY FORECAST AND GUIDANCE SUGGEST STEADY OR SLOWLY FALLING TEMPERATURES THIS AFTERNOON. PLAN TO MAKE ONLY MINOR CHANGES TO THE FORECAST. THE FORECAST FOR TONIGHT LOOKS LIKE IT PRETTY MUCH ON TARGET AS WELL WITH THE LAKE EFFECT SNOW SETTING UP. WILL LEAVE THIS ALONE FOR NOW. .MQT WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY THIS AFTERNOON MIZ002-009-084. SNOW ADVISORY THIS AFTERNOON MIZ001-003. WINTER STORM WARNING THIS AFTERNOON MIZ010>012 WINTER STORM WARNING THROUGH MIDNIGHT TONIGHT MIZ004-005-013-014. WINTER STORM WARNING THROUGH 6 AM EST THURSDAY MIZ006-007-085. GALE WARNING EAST HALF LAKE SUPERIOR && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1032 AM EST WED DEC 10 2003 .UPDATE...A NEGATIVELY TILTED MID LEVEL CUT OFF LOW CLEARLY VISIBLE IN THE LATEST SATELLITE IMAGERY OVER SOUTHERN ILLINOIS WILL MOVE INTO SOUTHERN INDIANA DURING THE AFTERNOON. THE ASSOCIATED OCCLUDED SURFACE LOW OVER NORTH CENTRAL ILLINOIS AT 15Z WILL MOVE INTO WESTERN LOWER MICHIGAN THIS AFTERNOON. PLUME OF DEEP MOISTURE IN ADVANCE OF THIS SYSTEM WILL CONTINUE TO REMAIN OVER MUCH OF LOWER MICHIGAN INTO THE EVENING. THUS FAR THIS MORNING...THE RAINFALL ASSOCIATED WITH THIS SYSTEM HAS FALLEN PRIMARILY SOUTHWEST OF A BAY CITY TO MT CLEMENS LINE. THIS LINES UP WELL WITH WHERE THE 12Z ETA SHOWS THE STRONGEST QG FORCING TO LIE. THE 12Z ETA AND THE LATEST RUC INDICATE LIFT SLOWLY ADVANCING INTO THE THUMB REGION THIS AFTERNOON...WITH LIFT PERSISTING ACROSS THE REST OF THE FORECAST AREA INTO THE EVENING. WILL THEREFORE CONTINUE TO MENTION CATEGORICAL POPS IN ALL ZONES. THUS FAR NO LIGHTNING AS BEEN OBSERVED WITH THIS SYSTEM THIS MORNING. AREA 12Z UPPER PLOTS GENERALLY SHOWED LITTLE IN THE WAY OF ELEVATED INSTABILITY. 12Z MESO ETA THETA-E CROSS SECTIONS DO INDICATE SOME POTENTIAL INSTABILITY IN THE 850-700MB LAYER THIS AFTERNOON...BUT THIS IS CAPPED BY A STABLE LAYER ABOVE 700 MB. POTENTIAL INSTABILITY OVER A DEEPER LAYER DEVELOPS ACROSS THE AREA AROUND 00Z...HOWEVER FORCING WILL NOT BE ALL THAT STRONG. SO HAVE OPTED TO REMOVE MENTION OF THUNDER ACROSS THE SOUTH. WITH PERSISTENT CLOUDS AND RAIN AND LOOKING AT UPSTREAM TEMPERATURES...DO NOT THINK TEMPS WILL RISE MUCH FROM CURRENT READINGS. WILL UPDATE THE MAX TEMPERATURES TO REFLECT THIS. && CONSIDINE .PREV DISCUSSION...ISSUED AT 107 AM. WELL DEVELOPED STORM SYSTEM OVER THE CENTRAL MISSISSIPPI VALLEY. CLOSED UPPER LOW OVER NORTHERN ARKANSAS/SOUTHERN MISSOURI TO LIFT NORTHEAST AND OPEN UP...AS IT IS ABSORBED BY A DEEPER UPPER LOW DROPPING INTO THE NORTH CENTRAL CONUS. IT IS THIS POLAR LOW WHICH WILL BE DELIVERING THE COLDEST AIR OF THE SEASON INTO LOWER MICHIGAN THURSDAY AND FRIDAY...EXTENDING INTO THE FIRST HALF OF THE WEEKEND. THE ONE SAVING GRACE FOR SOUTHEAST MICHIGAN IS THE LACK OF SNOW COVER. SOME DIFFERENCES BETWEEN THE ETA AND GFS DURING THE NEXT 24 HOURS. REGARDLESS...THEY BOTH COME TO THE SAME CONCLUSION FOR SOUTHEAST MICHIGAN...IT IS GOING TO RAIN THROUGH THIS EVENING. WILL BE CONTINUING WITH THE CATEGORICAL POPS. ALTHOUGH...HEAVIEST RAIN WILL LIKELY MISS SOUTHEAST MICHIGAN...AS BEST 850-700 MB FGEN FORCING WILL BE FOUND ACROSS LAKE MICHIGAN TODAY...AS AN INVERTED TROUGH REMAINS IN THAT GENERAL VICINITY. PREFERENCE IN THE SHORT TERM (NEXT 48 TO 60 HOURS)...IS FOR THE SLOWER GFS/NGM...PER HPC DISCUSSION. IT DOES LOOK LIKE THE ETA OPENS THE WAVE UP TOO SOON AND REMAINS TOO PROGRESSIVE. WILL BE KEEPING RUMBLE OF THUNDER IN THE FORECAST FOR THE SOUTHERN THIRD OF THE CWA...AND EXTENDING THE CHANCE IN THE EVENING...AS GFS IS INDICATING THE SHOWALTER INDEX FALLING TO AROUND 1 C...WITH K INDEX CLIMBING TO 30. LATEST DAY 1 OUT OF SPC...SHOWING CHANCE OF GENERAL THUNDER RIGHT NEAR THE MICHIGAN/OHIO BORDER. IMPRESSIVE COLD AIR ADVECTION TOMORROW MORNING...AS 12HR 850 MB TEMP CHANGE EXPECTED TO BE -21 C OVER CENTRAL LOWER MICHIGAN. NOT OVERLY OPTIMISTIC CONCERNING SNOW SHOWERS. SHORTWAVE RIDGING WILL BE OVER LOWER MICHIGAN ON THURSDAY...WHICH WILL KEEP INVERSION HEIGHTS PRETTY LOW...4000 FEET. CONSEQUENTLY...INSTABILITY IN THE LOW LEVELS LOOKS MINIMAL (LITTLE OR NO CAPE). NONE-THE-LESS...WITH 850 TEMPS DROPPING TO -10 TO -14 C DURING THE AFTERNOON AND 850 MB RH PROGGED TO BE 80 PERCENT OR GREATER ACROSS THE NORTHERN HALF OF THE CWA (PER GFS)...WOULD EXPECT TO SEE SOME FLAKES. BETTER CHANCE OF SNOW SHOWERS IS PROBABLY DURING THE MORNING...AS WE WILL HAVE SOME LINGERING MOISTURE HANGING AROUND WHEN THE COLD AIR SWEEPS IN. TROUGH AXIS TO MOVE INTO THE WESTERN GREAT LAKES FRIDAY MORNING. THIS WILL HELP RAISE INVERSION HEIGHTS A LITTLE. 00Z GFS NOT INDICATING AS MUCH MOISTURE AT 850 MB COMPARED TO YESTERDAY'S RUN. HOWEVER...00Z UKMET IS INDICATING MORE THAN ENOUGH MOISTURE...AS 850 MB RH PROGGED AT 95 PERCENT FOR MUCH OF SOUTHEAST MICHIGAN FRIDAY AFTERNOON. BOTH CANADIAN AND UKMET EVEN CLIP HURON COUNTY WITH MEASURABLE PRECIP. DON'T PLAN ON MAKING MANY CHANGES TO THE GOING FORECAST...BOTH WX AND TEMPS WISE. ETA/CANADIAN/GFS MODELS SHOW TROUGH AXIS SLIDING THROUGH LOWER MICHIGAN SATURDAY MORNING. AVERAGE TEMPS FRIDAY AND SATURDAY LOOK TO BE ABOUT 10 DEGREES BELOW NORMAL. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SF EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 947 AM EST WED DEC 10 2003 .DISCUSSION... SURFACE ANALYSIS SHOWS A WARM FRONT EXTENDING FROM NEAR SURF CITY...TO JUST WEST OF ILM...DOWN ALONG THE HORRY AND GEORGETOWN COUNTY COASTLINE. THIS FRONT WILL RAPIDLY MOVE INLAND DURING THE DAY PER THE 06Z ETA AND LATEST RUC...WITH SUBTROPICAL AIR BUILDING ACROSS ALL THE CWA. ONE BATCH OF SHOWERS CROSSED THE AREA EARLIER THIS MORNING...AND THE CWA IS CURRENTLY IN A LULL WAITING FOR THE NEXT BATCH OF SHOWERS TO MOVE IN FROM THE WEST. SPC CONTINUES TO MENTION SLIGHT RISK OF SVR TSTMS ACROSS JUST THE IMMEDIATE COASTAL COUNTIES WHERE DAYTIME HEATING WILL LIKELY HAVE THE MOST EFFECT. WIND PROFILES ARE IMPRESSIVE...BUT INSTABILITY WILL BE MARGINAL GIVEN UNIMPRESSIVE LOW LEVEL LAPSE RATES. (MID-DECEMBER SUNSHINE IS NOT VERY EFFICIENT AT DESTABILIZING THE ATMOSPHERE) WILL KEEP CURRENT SEVERE WORDING IN THE ZONES...BUT REMOVE HEAVY RAIN MENTION SINCE QUICK CELL MOVEMENT SHOULD LIMIT THAT THREAT. TEMPERATURES LOOK GOOD AND CURRENT CATEGORICAL POPS LOOK REASONABLE GIVEN RADAR PRESENTATION TO OUR WEST. && .MARINE... WILL NOT MAKE MAJOR CHANGES TO MORNING UPDATE AS CONDITIONS SEEM TO BE PROGRESSING AS PLANNED. SEAS UP AROUND 7.5 FEET OUT AT FPSN7 AND 41013 WITH SELY WINDS OF ABOUT 25 KTS GUSTING TO 30 KTS. WINDS ALONG THE COAST A BIT SLOWER TO PICK UP BUT SHOULD ONCE THE MORNING INVERSION BREAKS DOWN AND HIGHER WINDS MIX DOWN. GALE WARNING FROM CAPE FEAR NORTH...SCA TO THE SOUTH. && .PRELIMINARY POINT TEMPS/POPS... WILMINGTON 70 47 59 35 / 90 80 0 0 FLORENCE 66 43 57 34 / 90 60 0 0 LUMBERTON 66 43 57 33 / 90 60 0 0 MYRTLE BEACH 68 47 58 36 / 90 70 0 0 && .ILM WATCHES/WARNINGS/ADVISORIES... NC...GALE WARNING SURF CITY TO CAPE FEAR. SMALL CRAFT ADVISORY CAPE FEAR TO LITTLE RIVER INLET. SC...SMALL CRAFT ADVISORY LITTLE RIVER INLET TO S SANTEE RIVER. $$ PUBLIC...TRA MARINE...REK nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 930 AM CST WED DEC 12 2003 FORECAST CHALLENGE FOR UPDATE CONCERNS CLOUD TRENDS AND TEMPERATURES. BROAD NORTHERN STREAM MID LEVEL TROUGH REMAINS OVER FA TODAY WITH RUC INDICATING WEAK WAVE CROSSING AREA HOWEVER TOUGH TO PICK UP ON WATER VAPOR. AREA OF IFR-VFR CIGS ACROSS FA WITHIN TROUGH DRIFTING SE AND SHOULD WORK INTO SOUTHERN COUNTIES THIS MORNING. FLURRIES ALSO INDICATED BY METARS AIDED BY EXIT REGION OF UPPER JET. TEMPERATURES HAVE RECOVERED TO ABOVE ZERO UNDER CLOUDS. GENERALLY ACROSS THE REGION WITH CLOUDS AND COLD ADVECTION THERE SHOULD BE MINIMAL TEMPERATURE RECOVERY. CONCERN IS CLEARING ALONG CANADIAN BORDER WITH SUBZERO READINGS IN THIS AREA. AREAS ACROSS THE NORTH WHICH DO SEE CLEARING COULD POSSIBLY SEE TEMPERATURES FALL TODAY. WILL LOOK OVER TEMPERATURES AND PRETTY MUCH HOLD MAX TEMPERATURES CLOSE TO CURRENT READINGS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 145 PM CST WED DEC 10 2003 .DISCUSSION... SHORT TERM...TONIGHT THROUGH FRIDAY... BAND OF PRECIPITATION OVER WRN IL IN NICE DEFORMATION ZONE CONTINUES TO PRODUCE SNOW JUST OUTSIDE OF ILX FORECAST AREA. AS MAIN DYNAMICS PULL TO NORTHEAST...EXPECT OVERALL TREND OF WEAKENING TO CONTINUE. QUESTION IS HOW MUCH SNOW WILL IMPACT REGION THIS EVENING. RUC/ETA BOTH SUGGEST THERE IS SOME POTENTIAL FOR MEASURABLE IN NORTHEAST. HOWEVER...THE BULK OF THE SNOW LOOKS LIKE IT WILL BE JUST FLURRIES. FOR NOW WILL KEEP CHC S- NE AND FLURRIES SW. PRECIP MAY START OUT AS MIXTURE IN EAST. NICE CLEARING IN SHORT WAVE RIDGE LATE TONIGHT AND THURSDAY. STRONG CAA EVIDENT OVER UPPER MISSISSIPPI VALLEY SHOULD SWING DOWN INTO FORECAST AREA OVERNIGHT. LARGE DIFFERENCE IN ETA AND GFS GUIDANCE VALUES FOR HIGHS NEXT FEW DAYS. GIVEN CURRENT READINGS UPSTREAM...FEEL GFS PROBABLY CLOSER AND WILL GO WITH A GFS LEANING COMPROMISE. GUIDANCE CONSISTENT WITH LOWS. LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY... NEXT SYSTEM IN PROGRESSIVE STREAM PROGGED TO APPROACH AREA THIS WEEKEND. CONSIDERED PUSHING SNOW CHANCES INTO ONLY SOUTHERN ZONES WITH THIS SYSTEM. GFS ENSEMBLE MEAN SUGGESTS SURFACE HIGH MAY BE A BIT STRONGER AND FURTHER SOUTH ACROSS FORECAST AREA THAN OPERATIONAL 00Z GFS SUGGESTS. DECENT LIFT IS EVIDENT WITH SHORTWAVE IN TIME HEIGHT PLOTS BUT MOSTLY CONFINED TO 500 MB AND HIGHER NORTH OF I-72. CANADIAN 12Z ALSO SUGGESTS A FURTHER SOUTH POSITION. HOWEVER...ECMWF IS QUITE A WAY FURTHER NORTH AND 12Z AVN SEEMED TO BE TRENDING THAT DIRECTION. GIVEN UNCERTAINTY...WILL RETAIN CHANCE OF S- SATURDAY THROUGH SUNDAY SOUTH AND SATURDAY NIGHT THROUGH SUNDAY CENTRAL AND NORTH. ATTM IT DOES NOT APPEAR THAT SIGNIFICANT AMOUNTS ARE LIKELY. TEMPS APPEAR TO BE COLD ENOUGH THAT SNOW IS MOST LIKELY PRECIP TYPE. A BIT MORE IMPRESSIVE SYSTEM APPEARS ON TRACK FOR MIDDLE OF NEXT WEEK WITH STORM TRACK POISED TO CROSS FORECAST AREA. 00Z GFS BRINGING GOOD WAA AND MOISTURE IN ADVANCE OF SYSTEM WHICH SUGGESTS THAT BULK OF PRECIP MAY FALL AS LIQUID. HOWEVER...A SMALL CHANGE IN TRACK WILL MAKE A SUBSTANTIAL DIFFERENCE IN PRECIP TYPE. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...NONE. && $$ BARKER il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 503 PM EST WED DEC 10 2003 .DISCUSSION... SNOW HEADLINES ARE OF COURSE THE BIGGEST CONCERN IN THE SHORT TERM. AFTER TONIGHT'S STORM WINDS DOWN...MUCH COLDER TEMPS WITH LAKE EFFECT SNOW SHOWERS ARE IN STORE OVER THE NEXT COUPLE DAYS. SFC LOW IS NOW LOCATED IN SRN LAKE MICHIGAN...HAVING JUST PASSED NEAR CHICAGO. LOW POSITION IS WELL WEST OF WHAT MODELS HAD FORECAST OVER THE PAST MANY DAYS...AND GFS/ETA LOOKS TO BE HAVING A HARD TIME CATCHING UP. ON THE OTHER HAND...THE RUC APPEARS TO HAVE A HANDLE ON IT...AS IT TRACKS THE LOW THROUGH ALPENA TO NRN LAKE HURON BY 06Z. THIS SEEMS REASONABLE CONSIDERING SFC OBS IN EAST CENTRAL LOWER MI SHOWING BACKING WINDS YET...AND PRES FALL MAX IN NORTHERN LOWER MI. AS FAR AS SNOW GOES...RADAR LOOP SHOWS SYNOPTIC SNOW BEGINNING TO WIND DOWN IN THE FAR WEST...THOUGH ASX TO IWD STILL REPORTING LESS THAN 2 MILES IN SNOW AS THEY TRANSITION TO A LAKE EFFECT REGIME. SNOWFALL REPORTS THUS FAR HAVE RANGED GENERALLY FROM 4 TO 8 INCHES SO FAR ACROSS THE CWA...THOUGH LOCATIONS NEAR LAKE SUPERIOR FROM MARQUETTE EASTWARD HAVE RECIEVED VERY LITTLE AS TEMPS HAVE REMAINED IN THE LOW/MID 30S AND PCPN HAS MIXED WITH OR BEEN JUST RAIN. WOULD EXPECT ANY LINGERING RAIN NEAR THE SHORE TO CHANGE TO ALL SNOW THIS EVENING THOUGH AS COLDER AIR WORKS IN (NOTE TEMPS FROM CMX TO IWD HAVE ALREADY DROPPED INTO THE LOWER 20S). RUC SHOWS GOOD UPR DIVERGENCE AND H7 FRONTOGENESIS CONTINUING THIS EVENING...ENDING IN THE WEST AND SOUTH FROM 00-03Z...AND IN THE EAST AFTER 06Z. WITH SNOWFALL RATES OF 1/2 INCH TO AN INCH PER HOUR EXPECTED...AS WE HAVE SEEN THIS AFTN...WOULD EXPECT ANOTHER 2-6 INCHES OF SNOW TONIGHT... GREATEST OVER THE NORTH CENTRAL HIGHER TERRAIN (OROGRAPHIC LIFT) AND IN THE EAST (LONGEST DYNAMIC SUPPORT). REGARDING LAKE EFFECT... THOUGH DELTA-TS INCREASE TO NEAR 20C TONIGHT IN THE WEST...ACCUMS WILL BE LIMITED BY STRONG WINDS AND ADVECTION OF SOME VERY DRY AIR. DEW PTS ON NW SIDE OF LAKE SUPERIOR ARE IN THE LOWER SINGLE DIGITS...AND ETA SOUNDINGS CONTINUE TO SHOW INVERSION HEIGHTS OF ONLY 4-5KFT AS SYNOPTIC SNOW WANES. SO...THOUGH SNOW WILL BE FLYING...LES ACCUMS WILL NOT GET OUT OF HAND. WITH WESTERN TRACK OF SFC LOW AND RESULTANT TIGHTER PRES GRADIENT... HAVE SIDED W/ RUC WINDS WHICH SHOW 35-40KT IN BLYR LATE THIS AFTN THROUGH THE EVENING. ADVY WINDS HAVE BEEN OBSERVED OVER THE PAST COUPLE HOURS ON THE KEWEENAW...AND GALE FORCE GUSTS ARE NOW BEING REPORTED ON THE LAKE...SO THIS SEEMS ON TRACK. THUS...HAVE DECIDED TO EXTEND SNOW ADVY IN WEST AS A SNOW/BLSN ADVY THROUGH THE EVNG... AS CONDITIONS NOW ARE AS BAD AS THEY HAVE BEEN (GIVEN THE BLOWING/ DRIFTING OF INCREASINGLY POWDERY SNOW). AS HEAVIER SYNOPTIC SNOW WILL CONTINUE FOR ANOTHER FEW HRS IN SOUTH CENTRAL ZONES...HAVE EXTENDED WARNING FOR IRON THROUGH MENOMINEE CTYS UNTIL MIDNIGHT... AND WILL STRESS BLOWING SNOW THERE AS WELL. WILL LET EVENING SHIFT TAKE DOWN HEADLINES AS NEEDED. OTHER HEADLINES REMAIN INTACT. LAKE EFFECT SNOWS FOR THOSE LOCATIONS FAVORING NW WINDS WILL CONTINUE THROUGH FRIDAY. A COUPLE SHORTWAVES WILL HELP TO ENHANCE THIS SNOW...ONE THU NIGHT AND ANOTHER FRI...BUT DRY AIR WILL HAVE LIMITING EFFECT ON ACCUMS. LONGER LAKE FETCH FOR THE EAST WILL ALLOW FOR THEM TO HAVE GREATEST AMTS OVER THE NEXT COUPLE DAYS (THROUGH FRI)...AND A WITH A COUPLE INCHES HERE AND A COUPLE INCHES THERE IT WILL SLOWLY ADD UP. VERY COLD AIR IS ON THE WAY AS WELL. GFS SHOWS H8 TEMPS DROPPING TO -18C OR -20C BY THU NIGHT/FRI...AND A LOOK UPSTREAM SHOWS VERY COLD AIR INDEED (AFTN TEMPS IN MINUS TEENS IN NRN MANITOBA). SO WOULD EXPECT TWO OF COLDEST DAYS OF THE SEASON SO FAR IN THU AND FRI...WITH SOME INLAND TEMPS BELOW ZERO THU NIGHT AND FRI NIGHT (MODIFIED NEAR THE LAKE OF COURSE). DRY CONDITIONS ARE IN STORE FOR SAT AS HIGH SHIFTS TO THE SOUTHERN LAKES AND FLOW BACKS TO SWLY...SHIFTING ANY LAKE EFFECT SNOW TO THE ONTARIO SHORE. TEMPS WILL MODIFY INTO THE 20S SAT AS H8 TEMPS RISE TO AROUND -8/-10C. IN THE EXTENDED (SUN-TUE)...WEAK SHORTWAVE PASSES THROUGH THE AREA SUN. THOUGH DYNAMICS WITH THIS WAVE ARE LACKING...POOL OF COLD AIR ALF (-30C AT 500MB) WARRANTS MENTIONING LOW CHANCE SW FOR THE AFTN/ EVNG. OTHERWISE DRY CONDITIONS AS PER CURRENT FORECAST LOOK GOOD THROUGH MON...AS DEEPER TROUGH DIGS OUT WEST AND HEIGHTS BUILD OVER THE NORTHERN PLAINS. WILL THEN HAVE CHANCE OF SNOW FOR MON INTO TUE AS ROCKIES SYSTEM EMERGES INTO THE CENTRAL PLAINS...W/ GFS AND ENSEMBLE MEAN SHOWING INVERTED TROF EXTENDING NWD THROUGH THE WESTERN GREAT LAKES. TEMPS THROUGH THE EXTENDED SHOULD BE SEASONABLE...W/ 850MB TEMPERATURES REMAINING 5-8 DEGREES BELOW ZERO. .MQT WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY THROUGH MIDNIGHT MIZ001>003-009-084. WINTER STORM WARNING THROUGH MIDNIGHT MIZ004-005-013-010>014. WINTER STORM WARNING THROUGH 6 AM EST THURSDAY MIZ006-007-085. GALE WARNING EAST HALF LAKE SUPERIOR. && $$ JKL mi