AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 925 PM EST TUE MAR 14 2000 WINDS HAVE DECOUPLED OVER CWA THIS EVENING IN SPITE OF 20-30 KT WINDS JUST OFF THE DECK OBSERVED ON THE EOX/EVX RADARS. EARLIER VISIBLE SATELLITE AND CURRENT SURFACE DATA SUGGEST A POCKET OF SURFACE MOISTURE EXTENDING FROM CTY TO AMG THAT SPREAD W FROM THE NE FL COAST TODAY. LACK OF SURFACE FLOW SHOULD PREVENT THIS FROM AFFECTING FORECAST LOWS. THIN HIGH CLOUDS FROM AN MCS IN THE WRN GULF ARE STREAMING E OVER THE CWA...WHICH MAY MODERATE FORECAST LOWS SLIGHTLY. EXCEPT FOR SKY COVER...BELIEVE CURRENT ZONE PACKAGE IS STILL ON TRACK. MARINE - 15/01Z RUC FORECASTS WIND OVER THE COASTAL ZONES TO INCREASE AND VEER TO THE E-SE BY MORNING. CURRENT OBSERVATIONS AGREE FAIRLY WELL WITH COASTAL WATERS FORECAST. OTHER THAN MINOR ADJUSTMENTS TO DIRECTION...NO CHANGES ARE PLANNED. .TLH...NONE. TJT fl AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE DES MOINES IA 950 AM CST TUE MAR 14 2000 SHORT TERM... UPDATE TO ZONES HAS BEEN SENT TO REMOVE RAINFALL AND TO MAKE SLIGHT ADJUSTMENTS TO CLOUDS AND TEMPS. WAA GENERATED SHRA HAVE CLEARED THE CWA. RAINFALL IS ALSO REMAINING JUST TO THE S OF THE BORDER IN MO. SATELLITE TRENDS INDICATE A CLEARING TREND LIKELY IN THE SW AND SC ZONES BY EARLY AFTERNOON. MORNING SOUNDINGS INDICATED THAT TEMP FORECASTS ONLY NEEDED SLIGHT MODIFICATIONS. RUC FORECASTS ALSO SHOW 55-60 MOST OF CENTRAL AND SW. .DSM...NONE KULA ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 850 PM CST TUE MAR 14 2000 BASED ON LATEST SATELLITE AND RADAR TRENDS...AS WELL AS OUTPUT FROM THE 00Z RUC...WILL BE UPDATING THE ZONES TO LOWER POPS CONSIDERABLY...ESPECIALLY ACROSS THE SRN 1/2 OF THE AREA. LINE OF STORMS EXTENDING FROM EXTREME NW MX...ACROSS THE BRO AREA AND OUT INTO THE GULF HAS BECOME THE DOMINANT FEATURE IN THE AREA. IT WILL BE DIFFICULT FOR ANY OTHER SIGNIFICANT PRECIP TO DEVELOP IN THE VICINITY AS THERE IS PROBABLY QUITE A BIT OF SUBSIDENCE SURROUNDING THE MCS. OTHER SCATTERED TSRA WERE NOTED IN THE RIO GRANDE VALLEY...BUT THIS ACTIVITY WILL LIKELY TAKE A COURSE TO OUR SOUTH AS WELL...AND IT WOULD TAKE SEVERAL HOURS TO GET INTO OUR AREA ANYWAY. WILL PROBABLY CUT BACK TO GOOD CHANCE IN THE SOUTH AS THE HIGHEST POPS...20-40 FARTHER NORTH. 05 .SHV...NONE. la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1120 PM EST TUE MAR 14 2000 UPDATE CONCERNS ARE WITH CURRENT ONGOING SNOW AND HEAVIER SNOW LATE TONIGHT/WEDNESDAY. 00Z RAOBS/WATER VAPOR LOOP SHOWS SHORTWAVE NEAR EASTERN MONTANA/WESTERN DAKOTAS. SURFACE ANALYSIS PLACES LOW PRESSURE OVER SOUTH DAKOTA...MOVING EAST ALONG TIGHT BAROCLINIC ZONE EXTENDING ACROSS MINNESOTA...WISCONSIN AND LOWER MICHIGAN. REGIONAL RADARS SHOW A NARROW BAND OF 1-3SM -SN FROM NORTH-CENTRAL MINNESOTA ACROSS THE UPPER PENINSULA...JUST NORTH OF THE SURFACE BOUNDARY. SNOW WILL INCREASE IN INTENSITY/COVERAGE AS THE SYSTEM RACES EASTWARD. 18Z AND 00Z ETAS BRING THE LOW FURTHER NORTH THAN PREVIOUSLY...PUSHING THE HEAVIEST PRECIP ACROSS MORE OF THE NORTHERN CWA. 00Z NGM AND RECENT RUC RUNS TRACK THE LOW A BIT TO THE SOUTH...KEEPING THE HEAVIEST PRECIP ACROSS THE CENTRAL CWA. EXPECT GENERAL ACCUMULATIONS OF UP TO 2 INCHES OF SNOW ACROSS MOST OF THE UPPER PENINSULA DURING THE OVERNIGHT HOURS. INTENSE BANDS EMBEDDED IN THE MAIN AREA OF SNOW ARE APPARENT ON THE MQT 88D...BUT THESE AREAS ARE GENERALLY LOCALIZED AND WIDESPREAD. WITH A MORE NORTHERLY TRACK POSSIBLE...WILL ADD HOUGHTON/KEWEENAW COUNTIES TO THE WATCH. WITH SNOW TO INCREASE LATE TONIGHT...UPGRADED GOGEBIC/ONTONAGON COUNTIES TO A WARNING WITH 4 TO 8 INCHES LOCAL 10 INCHES TOTAL ACCUMULATION. THANKS TO DLH/GRB FOR COORDINATION. .MQT...WINTER STORM WARNING LATE TONIGHT INTO WEDNESDAY MIZ002-009 WINTER STORM WATCH WEDNESDAY MIZ001-003>007-010-011-012-013. JHB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 943 PM EST TUE MAR 14 2000 THUS FAR...RATHER COMPLICATED WEATHER PICTURE ACROSS THE ERN UPR/NRN LWR REGION IS PROCEEDING AS PLANNED...THOUGH WITH A FEW SURPRISES WITH THE HEAVIER SNOW BANDS NEAR THE STRAITS REGION. LATE EVENING ZONE FORECAST UPDATE WILL BASED ON LATEST PRECIPITATION TRENDS -- BOTH TYPE...AREAL EXTENT...AND AMOUNTS IN THE STRAITS AREA. CURRENT SFC ANALYSIS INDICATES STATIONARY FRONT NOW SOUTH OF THE MACKINAC BRIDGE...BASICALLY EXTENDING FROM FRANKFORT EAST TO GRAYLING AND HARRISVILLE. SFC WINDS HAVE SWUNG AROUND TO THE N/NE NORTH OF THE FRONT. ONCE AGAIN...REGION IS WITHIN A FAIRLY STRONG STRETCHING DEFORMATION ZONE BOTH AT THE SFC AND ALOFT...INDICATIVE OF STRONG NORTH-SOUTH LOWER AND MID LVL FRONTOGENESIS/BAROCLINICITY. 12Z MODEL RUNS...ALONG WITH THE 18Z ETA AND 21Z RUC...HAVE VERIFIED FAIRLY WELL WITH FRONTAL BOUNDARY SAGGING A BIT FARTHER SOUTH THIS EVENING...IN WAKE OF THE NRN STREAM SHORTWAVE TROUGH PASSING NORTH OF THE REGION. AS WITH THE 12Z ETA...18Z ETA AND LATEST RUC SHOW SFC BOUNDARY DROPPING A LITTLE FARTHER SOUTH YET LATE TONIGHT (PERHAPS AT LEAST TO THE M-55 CORRIDOR) GIVEN THE INCREASING RRQ JET FORCING...WITH Q-VECTORS (AND THUS LOW LEVEL AGEOSTROPHIC FLOW) BECOMING ORIENTED MORE NORTH-TO-SOUTH. PRIMARY CONCERN TONIGHT IS WITH HEAVIER SNOW BANDS UNDERNEATH STRONGEST 700 MB DEFORMATION NORTH OF THE SFC FRONT...WHICH AT THIS TIME IS ACROSS THE STRAITS REGION. A REPORT OF 2" OF SNOW IN 2 HRS CAME IN RECENTLY FROM THE ST IGNACE AREA. LATEST RUC PROGS INDICATE 700 MB DEFORMATION MAXIMUM CURRENTLY ACROSS THE STRAITS REGION WILL WEAKEN A BIT OVERNIGHT...THOUGH MID LEVEL FRONTOGENESIS GRADIENT/ Q-VECTOR CONVERGENCE AND THUS UPPER DIVERGENCE REMAIN IN PLACE... WHILE AT THE SAME TIME BROADENING A BIT FARTHER SOUTH INTO NRN LWR. WILL THEREFORE BOOST SNOW TOTALS NEAR THE STRAITS REGION...AND ADJUST THE TIMING OF STEADIER SNOWS WORKING INTO THE FAR NRN LWR ZONES. Q-G FORCING/MID LEVEL DEFORMATION SOUTH OF A TRAVERSE CITY- HARRISVILLE LINE TO REMAIN MUCH WEAKER OVERNIGHT...RESULTING IN MORE SCATTERED TYPE PRECIP (TYPICAL ALONG/SOUTH OF A SFC WARM FRONT). WILL CONTINUE TO KEEP PRECIP TYPE MAINLY RAIN IN THESE AREAS... WITH RAIN/SNOW MIX IN THE VICINITY OF WARM FRONT. FORECAST UPDATE EXPECTED OUT BETWEEN 1000 AND 1030 PM. .APX...NONE. HURLEY mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 605 PM EST TUE MAR 14 2000 ...UPDATE TO PUT SCATTERED SHOWERS IN FORECAST THIS EVENING... LATEST RADAR MOSAIC LOOPS INDICATED AN AREA OF SCATTERED SHOWERS OVER SRN WI AND CNTL LOWER MI. ECHOES HAVE REFLECTIVITIES AS HIGH AS 35 DBZ NORTH OF OVER CNTL LWR MI. THERE IS A SECOND AREA OF RAIN SOUTH OF MI OVER IL AND WRN IN AT 23Z. THE AREA OVER CNTL LWR MI IS ASSOCIATED WITH JET ASSISTED LIFT (RUC 300 MB DIVERGENCE) AND LIFT OVER THE NEARLY STATIONARY FRONT OVER NRN LWR MI. SFC DEWPOINTS ARE NEAR FREEZING AND WET BULB ZERO IS CLOSE ENOUGH TO THE GROUND THAT SOME SLEET HAS BEEN REPORTED EARLIER FROM SOME OF THE SHOWERS. WHILE A LOT OF THIS PRECIPITATION IS NOT REACHING THE GROUND AS MORE MOIST AIR CONTINUES TO MOVE IN FROM THE SOUTH... MORE OF THIS WILL REACH THE GROUND WITH TIME SO UPDATED NRN PART OF CWA TO SCATTERED SHOWERS/POSSIBLE SLEET/ THEN RAIN LIKELY OVERNIGHT. AREA OF PCPN TO OUR SOUTH WILL MOVE NORTHEAST INTO CWA THANKS TO ISENTROPIC LIFT WHICH IS RELATED TO APPROACHING NRN STREAM WAVE INTERACTING WITH SRN STREAM. UPDATED SRN 1/2 OF CWA TO WIDELY SCATTERED SHOWER THIS EVENING WITH RAIN DEVELOPING OVERNIGHT. .GRR...NONE. WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 915 AM EST TUE MAR 14 2000 PATCH OF CI MOVING OVHD ATTM...W/ MORE HIGH CLOUDINESS POISED TO THE W IN ZONAL FLOW ALOFT. CI IS THIN AND MOSTLY SUNNY SKIES WILL CONTINUE TO BE THE RULE. WEAK CYCLONIC SWIRL SEEN IN THE LOW CLOUDS OFF THE SC COAST. RUC SFC WIND FIELD INITIALIZES THIS FEATURE WELL ...BUT APPEARS TO LOSE IT TOO QUICKLY. IF ANYTHING...ONLY EXPECTING THIS FEATURE TO DELAY VEERING WIND DIR (ESP IN THE CWF)... AND THE LOW CLOUDS REMAINING OFFSHORE. LOW-LEVEL THICKNESS SCHEME AND LAMP PROJECTIONS SUPPORT FCST TEMPS FOR TODAY...REST OF TODAY/S FCST LOOKS GOOD TOO. CWF: W/ WEAK LOW OFF THE COAST WILL PROBABLY HAVE TO INITIALIZE W/ A N WIND DIR. ENOUGH OF A PGF TO KEEP WINDS AT 15 KT THIS AFTERNOON. .ILM...NONE. PFAFF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 930 PM TUE MAR 14 2000 IR SATELLITE IMAGERY SHOWING HIGH CLOUDINESS THINNING AS IT MOVES EASTWARD TOWARD THE FORECAST AREA. THE 18Z ETA AND THE RUC BOTH BRING A WEAK VORT CENTER AND AN UPPER JET ACROSS THE REGION OVERNITE...RESULTING IN SOME WEAK UPPER FORCING. WHILE THE EFFECTS SHOULD BE MINIMAL...THIS BIT OF FORCING SHOULD AT LEAST BE ENOUGH TO BRING SOME OF THE MID/HIGH CLOUDS IN BY MORNING. WITH THAT IN MIND...CURRENT SET OF ZONES LOOKS OK FOR NOW. WILL NOT CHANGE TEMPS AT THIS POINT. .GSP...NONE. MOORE sc AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 850 PM CST TUE MAR 14 2000 LATEST RUC AND ETA MDLS SHOW THAT THE SNOW WILL REMAIN ALONG THE ND BORDER NORTH OF ABR...EAST TO WHEATON AND ORTONVILLE IN WC MN WITH ACCUMULATIONS OF 1 TO 2 INHCES. THE HEAVIEST SNOWFALL WILL REMAIN IN ND AND MN. LATE THIS EVENING...THE RADAR MOSAIC AND SFC OBS WERE SHOWING WIDESPREAD SNOWFALL IN THE AFOREMENTIONED AREA. SFC LOW WILL MOVE QUICKLY INTO S MN BY 12Z WED AS COLDER AIR...BREEZY N TO NE WINDS AND LOW CLOUDS OVERTAKE THE CWA. HAVE UPDATED FORECAST TO INCREASE POPS SOME AREAS AND LOWER OR TAKE POPS OUT FOR OTHER AREAS. ALSO INCREASED WINDS AND LOWERED OVERNIGHT LOWS SOME. .ABR...NONE MOHR sd AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE SAN ANGELO TX 924 PM CST TUE MAR 14 2000 AREA RADARS INDICATE ISOLATED SHOWERS AND THUNDERSTORMS HAVE DISSIPATED...AS BOUNDARY LAYER INSTABILITY HAS WANED SINCE SUNSET. 00Z RUC AND 00Z ETA INDICATE OUR SOUTHERN COUNTIES WILL BE UNDER WEAK POSITIVE 300 MB IPV ADVECTION THROUGH 12Z...AND 00Z DRT SOUNDING SHOWS ELEVATED INSTABILITY. WILL KEEP 1ST PERIOD POPS ACROSS THE SE ZONES...AND REMOVE POPS ELSEWHERE. REGARDING TEMPS...KJCT ALREADY AT FORECASTED OVERNIGHT LOW...WITH DEWPOINTS IN THE LOWER 50S. WILL DROP TEMPS AND WINDS OVER THE SOUTHERN ZONES. REST OF FORECAST IN GOOD SHAPE. 14 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 252 PM CST TUE MAR 14 2000 FCST CONCERNS ARE TEMPS AND TIMING PCPN CHCS THRU WED. CLDS AND SPRINKLES/--SHRA FORMING IN MOIST CONVERG ZONE OVR CWA... BETWEEN SUBTLE SFC BNDRY LAYING ACROSS CNTRL WI AND WK DISTURBANCE PASSING TO OUR SOUTH THRU CNTRL IL. PCPN ASSOC WITH LFQ OF UPR JET SPREADING ACROSS ARROWHD OF MN. SFC LO DVLPG IN WRN DKTS WL BE MAIN WX MAKER FOR WI THE NEXT 24-36 HRS. NCEP MDLS IN GUD AGREEMENT WITH UPR LVLS...TAKING FIRST JET MAX ACRS NRN WI/UP ERLY TNT...WITH ANOTHER E/W ORIENTED SPD MAX FAST ON IT/S HEELS. CPLG OF JETS OVR THE FAR NORTH COULD GIVE THEM SOME HVY SNOW. RRQ WILL BE AFFECTING OUR CWA. DIFFERENCES IN SPEED...STRENGTH AND TIMING OF H5 VORT AND H5 TROF. AVN MORE COMPACT AT FIRST...BUT COMES IN LINE WITH ETA AND NGM AND A MORE SHEARED LOOK BY 36 HRS. H5 WAVE HANGS UP UNTIL ENERGY ROUNDS BASE OF TROF THRU KS THU AM. NGM/AVN BRING TROF AXIS OVR CWA...WITH ETA KPG IT BACK TO THE NW. H7 RH AND UVV PANELS INDICATE BEST MOISTURE AND LIFT SE OF CWA BY 00Z THU. NGM/AVN HAVE BETTER HNDL ON SFC LO AT 18Z...WITH 18Z RUC FOLLOWING NGM SPEED. LO CROSSES ST TMRW MORNING...AND INTO LWR MI BY 00Z. CHC POPS TNT AS WAA KICKS IN...LIKELY FOR TMRW. ALL LIQUID AS SNDGS AND GUIDNC KEEP TEMPS ABV FREEZING TNT IN LOWEST 3K FT IN SRLY FLO AHD OF LO. TEMPS WL STAY UP WITH H8 CAA NOT STARTING UNTIL AFTER 18Z ACRS CWA. LI/S APPCHG ZERO AND SOME CAPE AROUND 18Z ON BUFKIT SNDGS MEAN CHC OF SOME EMBEDDED THUNDER. WONT MENTION SN..AS PCPN ENDING BEFORE COLDEST AIR WRKS IN. WL TEND TWD HIER FWC TEMPS VS FAN FOR ERLY HI/S WED...THO 3 HRLY VALUES LOOK BETTER THAN 12 HR TEMPS GIVEN CLDS AND PCPN. .UWNMS...SIMILAR TO NCEP MDLS BUT BRING SFC LO FARTHER SOUTH.THUS 2M TEMPS ARE COOLER. THANKS TO GRB FOR COORD .MKX...NONE. 0...0...0...0 $$ REM wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 300 AM CST WED MAR 15 2000 SEVERAL FORECAST CONCERNS THIS PACKAGE...INCLUDING TIMING OF PRECIP/COLD FRONT AND WHETHER OR NOT A CHANGE IN PRECIP TYPE WILL OCCUR. FIRST OFF...LINGERING SCATTERED SHOWERS CONTINUE TO DEVELOP IN NRN MO AND PROPAGATE INTO CENT IL. IT APPEARS THAT THE SHOWERS ARE DEVELOPING IN AN AREA OF LOW LEVEL MOISTURE CONVERGENCE/ CONTINUED WARM AIR ADVECTION...AND IN THE VICINITY OF A WEAK SURFACE TROF FROM SE KANSAS TO WCENT IL. WILL PUT MENTION OF WIDELY SCATTERED SHOWERS IN FORECAST FOR THIS MORNING DUE TO EXISITING CONDITIONS AND FACT THAT RUC KEEPS MOISTURE CONVERGENCE UNTIL AT LEAST 15Z. UPPER FLOW ACROSS THE COUNTRY WILL BECOME MORE AMPLIFIED TODAY AS A PROGRESSIVE TROUGH IN THE PACIFIC PUSHES INTO THE WEST COAST BY THURSDAY. THIS WILL ALLOW A TROUGH CURRENTLY IN THE NW U.S. TO DROP INTO THE SOUTHERN PLAINS...WITH A SHORTWAVE ROTATING AROUND THE POLAR VORTEX ACROSS THE UPPER MIDWEST. THIS WILL ALLOW CHILLY AIR TO PUSH SOUTH INTO THE NATIONS MIDSECTION. THE MODELS ARE ALL FAIRLY SIMILAR IN THEIR DEPICTION OF THIS SCENARIO. FOR CENT IL THIS MEANS THAT A COLD FRONT ACROSS THE NRN TIER OF THE U.S. IS FINALLY GETTING A PUSH OF COLD AIR BEHIND IT...WHICH WILL SURGE SOUTH INTO OUR REGION THIS EVENING. PLENTY OF CONVERGENCE NEAR THE BOUNDARY WILL COMBINE WITH SOME UPPER FORCING DUE TO THE PROXIMITY OF THE RIGHT ENTRANCE REGION OF THE JET. THESE FORCING MECHANISMS...ALONG WITH INCREASING LOW LEVEL MOISTURE WILL RESULT IN SHOWERS DEVELOPING JUST AHEAD OF THE FRONT IN CENTRAL IL LATE THIS AFTERNOON. A NARROW RIBBON OF WEAK INSTABILITY ALONG THE FRONT MAY BE ENOUGH TO FORCE A FEW THUNDERSTORMS MAINLY WEST OF A BMI-DEC LINE LATE THIS AFTERNOON INTO EARLY THIS EVENING. DECREASING LEVELS OF INSTABILITY AND LOW LEVEL CONVERGENCE LATER IN THE EVENING SHOULD RESULT IN VERY FEW IF ANY THUNDERSTORMS IN ECENT AND SE ILLINOIS. PROBLEM FOR LATE TONIGHT AND THURSDAY MORNING IS CENTRAL ILLINOIS IS THE TIMING OF THE COLD AIR AND END OF THE PRECIPITATION. LOOKS LIKE THE COLD AIR MAY REACH LOCATIONS FROM ABOUT GBG-BMI IN TIME TO CHANGE THE RAIN TO LIGHT SNOW TOWARD DAYBREAK. AVN/NGM ALSO INDICATE THE PRESENCE OF MID/UPR LEVEL CLOUDS DURING THE DAY THURSDAY...WHICH MAY SEED LOWER CLOUDS WITH ENOUGH ICE TO PRODUCE SCTD AREAS OF LIGHT SNOW. WILL ADDRESS THIS WITH CHANCE POPS FOR LIGHT SNOW THURSDAY. THE FRONT DROPS INTO THE OH VALLEY BY THURSDAY MORNING...ALTHOUGH A LITTLE LINGERING MID LEVEL QG FORCING BEHIND THE FRONT WILL RESULT IN A CONTINUATION OF LIGHT RAIN IN ECENT AND SE SECTIONS THURSDAY. IF THE RAIN LINGERS TOO LONG...THE AFOREMENTIONED ADVECTION OF COLD AIR IN THE LOWER LEVELS MAY ALSO PRODUCE A RAIN/SNOW MIX. FOR NOW WILL STICK WITH CURRENT ZONE FORECAST THAT HAS THIS MENTION FOR CMI-DNV-MTO. ...PRELIMINARY CCF FOR COORDINATION ONLY... SPI CE 059/035 038/021 036 23484 PIA WE 057/033 036/019 033 23684 DEC CE 059/034 038/020 036 23484 CMI EC 061/039 039/020 035 23385 MTO EC 063/043 043/025 038 23385 LWV EC 066/045 045/028 040 23287 .ILX... IL...NONE. MILLER il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 230 PM CST TUE MAR 14 2000 ...CURRENT OVERVIEW... RADAR MOSAIC SHOWING AREA OF -RA ACROSS SOUTHERN IOWA...MISSOURI AND CENTRAL ILLINOIS. KDVN WSR-88D ALSO SHOWING EXPANSIVE ECHOES NORTH OF I-80 WITH ALL PCPN LIFTING E/NE FAIRLY QUICKLY. PCPN DEVELOPING IN RESPONSE TO SHORTWAVE OVER NORTHWEST MISSOURI...AND HAVING TOUGH TIME REACHING GROUND OVER ALL BUT FAR SOUTH WITH 12Z KDVN SOUNDING SHOWING DRY LOW LEVELS. WATERLOO(KALO) MANAGED TO PICK UP .03 WITH DUBUQUE(KDBQ) RECENTLY REPORTING -RA...SO AT BEST JUST A FEW SPRINKLES OR BRIEF -SHRA. LATEST SFC/MSAS ANALYS SHOWS ARCTIC BOUNDARY STRUNG OUT WELL TO THE NORTH FROM THE DAKOTAS INTO NORTHERN WISCONSIN. WEAK TROF NOTED VICINITY OF MASON CITY (KMCW) TO DENISON (KDNS). FURTHER SOUTH BUBBLE HIGH ANALYZED WEST OF COLUMBIA MISSOURI (KCOU) WITH DEVELOPING WARM FRONT EXTENDING FROM LOW PRESSURE OVER WEST TEXAS THRU NORTHERN OKLAHOMA INTO SOUTHERN MISSOURI. INTERACTION OF BUBBLE HIGH AND WARM FRONT HAS LEAD TO SOME INTENSIFICATION OF TSTMS OVER SOUTHWEST MISSOURI. LOW LEVEL SOUTHWEST FLOW/COMPRESSIONAL HEATING AHEAD OF WEAK SFC TROF HAS BOOSTED TEMPS WELL INTO THE 50S ACROSS CWA WITH A FEW AREAS HITTING 60 DEGS CENTRAL/SOUTHERN ZONES. BRIEF SHOWER KNOCKED DUBUQUE (KDBQ) BACK TO 47 DEGS LAST HOUR. MAIN CONCERNS ARE WITH PCPN CHCS WED/WED NGT ALONG WITH CLOUDS AND TEMPS THROUGHOUT. ...SHORT TERM (0-24 HRS)... MODELS INITIALIZED REASONABLY WELL WITH SHORTWAVE OVER NORTHWEST MISSOURI AND MOVE IT EAST OF REGION BY 06Z. MAIN FORCING/DYNAMICS TO AFFECT SOUTHERN AND FAR EASTERN AREAS. MAY GO WITH LOW POPS THESE AREAS FOR THIS EVENING...THOUGH LATEST RADAR TRENDS WILL DICTATE. VISIBLE SATELLITE SHOWS CLEARING INTO NORTHWEST/WESTERN IOWA. MODELS NOT DOING WELL WITH CLOUD TRENDS...THOUGH LATEST RUC APPEARS TO HAVE BEST HANDLE AND WILL GENERALLY FOLLOW FOR TONIGHT. CU FIELD DEVELOPING ON WESTERN EDGE OF CLOUD SHIELD FROM CENTRAL INTO SOUTHWEST IOWA SHOULD DISSIPATE WITH LOSS OF HEATING...LEAVING BEHIND LOW/MID CLOUDS IN ASSOCIATION WITH SHORTWAVE. VISIBLE SATELLITE ALSO SHOWS LARGE PLUME OF CIRRUS STREAMING THRU PLAINS AHEAD OF NEXT SYSTEM. RUC KEEPS SOME LOW/MID CLOUDS AROUND TONIGHT WITH WARM AIR ADVECTION DEVELOPING BEHIND WAVE...AND ALSO SHOWS CIRRUS THICKENING OVERNIGHT. THAT BEING SAID PTCLDY/MOCLDY SHOULD SUFFICE. LOW TEMPS A TOUGH CALL. WITH ENOUGH MIXING AND DEWPTS SLOWLY CLIMBING DURING NIGHT...WILL CERTAINLY NOT UNDERCUT GUIDANCE AND MAY GO A FEW DEGS WARMER. COULD SEE PATCHY FOG AGAIN TONIGHT WITH WARM AIR ADVECTION... HOWEVER ENOUGH MIXING SHOULD KEEP IT IN CHECK. ...LONG TERM (24-48 HRS)... UPPER PATTERN TO TRANSITION FROM NEARLY ZONAL TO HIGHLY AMPLIFIED FLOW BY END OF PD. MODELS IN REASONABLE AGREEMENT ON DROPPING ARCTIC BOUNDARY...NOW OVER DAKOTAS/CENTRAL MINNESOTA/NORTHERN WISCONSIN... SLOWLY SOUTHWARD INTO SOUTHERN MINNESOTA/CENTRAL WISCONSIN BY 12Z WED ...FASTER THAN PREVIOUS RUNS. PRE-FRONTAL TROF/WIND SHIFT TO EXTEND ACROSS WESTERN IOWA DURING SAME TIMEFRAME. MODELS EXHIBITING TIMING DIFFERENCES ON INITIAL TROF/WIND SHIFT WHICH WILL HAVE BIG IMPACT ON MOISTURE AVAILABILTY AND PCPN CHCS. NGM QUICKEST BRINGING SFC TROF INTO CENTRAL IOWA BY 12Z...ETA SLOWEST AND AVN...AS USUAL...MIDDLE OF ROAD. AVN SHOWING DECENT RUN TO RUN CONTINUITY AND FAVOR BLEND OF SLOWER AVN/ETA WITH MAIN VORT DIGGING THRU ROCKIES AND TAKING A MORE SHEARED LOOK ACROSS PLAINS/UPPER MIDWEST. NGM BEING QUICKEST ALSO DRIEST WITH DYNAMICS OUTRUNNING MOISTURE. ETA/AVN VERIFYING MUCH BETTER AT 18Z WITH REGARDS TO LOW LEVEL MOISTURE OVER SOUTHERN PLAINS. THEIR SLOWER SOLUTIONS WILL ALLOW MORE TIME FOR THIS MOISTURE TO MEET UP WITH DYNAMICS GIVING US BETTER CHC FOR PCPN. BOTH ETA/AVN SHOW SFC DEWPTS CLIMBING INTO THE U40S/L50S DURING EARLY AFTERNOON WITH GRADIENT NOSING INTO FAR WESTERN ZONES. WILL PLACE HIGHEST POPS EAST OF RIVER...AND LOWEST POPS OVER WESTERN ZONES WITH BULK OF PCPN STARTING LATE MORNING INTO AFTERNOON FROM WEST TO EAST. TSTMS POSSIBLE WITH AVN SHOWING LI/S APPROACHING ZERO AS FAR NORTH AS QUAD CITIES. LIMITED INSTABILITY (CAPES BETWEEN 100-200 J/KG AND LI/S NEAR ZERO) WILL SQUELCH ANY POTENTIAL FOR STRONG TO SEVERE TSTMS EVEN GIVEN TIME OF FROPA (AFTN/EVE) ARCTIC FRONT TO SWEEP ACROSS REGION WEDNESDAY NIGHT. COULD SEE BREAK IN PCPN DURING EVENING BEFORE MORE LIGHT PCPN ACCOMPANIES ARCTIC FRONT AND SHEARED UPPER VORT. INITIALLY EXPECT LIGHT RAIN...BUT AS H85 TEMPS AND THICKNESSES CRASH COULD SEE SOME WET SNOWFLAKES MIXED IN BEFORE ENDING EARLY THURSDAY MORNING. AVN HINTING AT ANOTHER WAVE TO DROP SOUTH ACROSS AREA...AND GIVEN CYCLONIC FLOW AND LINGERING MOISTURE COULD SEE SCATTERED FLURRIES OR PERHAPS A FEW SNOW SHOWERS. MAX TEMPS WEDNESDAY WILL BE TRICKY. SOUTHWEST FLOW AHEAD OF TROF YIELDS GOOD COMPRESSIONAL HEATING...THOUGH CLOUDS AND ANY PCPN SHOULD NEGATE SOME OF THIS. LEANING TOWARD GOING SLIGHTLY ABOVE GUIDANCE. ANY SUNSHINE...AND TEMPS COULD SOAR...SO BEWARE POTENTIAL BUST. GUIDANCE IN GENERAL AGREEMENT IN LATER PERIODS AND WON/T STRAY TOO FAR BUT WILL TWEEK. ...EXTENDED (FRI-SUN)... CANADIAN HIGH PRESSURE BUILDS SOUTH ACROSS AREA FRIDAY RESULTING IN DRY BUT COLD CONDITIONS. MRF SHIFTS CANADIAN HIGH EAST ON SATURDAY WITH RETURN FLOW COMMENCING AHEAD OF DEVELOPING SYSTEM OVER PLAINS. MRF ABOUT 12-18 HRS SLOWER WITH SYSTEM THAN PREVIOUS RUN AND STILL MIGHT BE TOO QUICK TO REMOVE CANADIAN HIGH. UPPER TROF WORKS INTO AREA SUNDAY WITH MRF DEVELOPING CLOSED LOW OVER LOWER MISSISSIPPI VALLEY AND LIFTING E/NE INTO OHIO VALLEY EARLY NEXT WEEK. WILL DELAY PCPN CHCS UNTIL SUNDAY. .DVN... IA...NONE. IL...NONE. MO...NONE. M^2 il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 315 AM EST WED MAR 15 2000 KIWX RADAR SHOWING BULK OF PRECIP CURRENTLY EXITING NE CWA ATTM. MODELS SHOW THIS LIFTING NE OUT OF THE AREA EARLY THIS MORNING. HOWEVER...KILX STILL SHOWING A FEW STRAY SHOWERS EXTENDING BACK INTO NC IL. WILL MONITOR RADAR TRENDS AND TAKE A QUICK LOOK AT LATEST RUC BEFORE DECIDING ON ONGOING PRECIP THIS MORNING. 06HR ETA APPEARS TO HAVE BEST DEPICTION OF CURRENT PRECIP TRENDS WHILE AVN SEEMS MORE REASONABLE WITH SPEED OF FRONT AND ASSOCIATED MOISTURE AND PRECIP IN LATER PERIODS. SAT LOOP AND MODEL MOISTURE FIELDS INDICATE BEST CHANCE FOR CLOUDS TO MIX OUT TODAY WILL BE MAINLY SOUTH OF OUR AREA. 850MB TRAJ AND MODEL FCST OF 850MB TEMPS BOTH POINT TOWARDS HIGHS NEAR 60 TODAY. THIS SEEMS VERY POSSIBLE IF WE CAN GET SOME SUN BUT WILL OPT FOR RANGE OF 55 TO 60 IN CASE CLOUDS HANG TOUGH. TIMING OF PRECIP WITH APPROACHING FRONT WILL OCCUR AFTER 00Z EXCEPT IN NW WHERE WILL KEEP AN AFTN CHANCE IN. WILL GO WITH CAT POPS PER GUIDANCE IN NW TONIGHT AND TAPER DOWN TO LIKELY ELSEWHERE. MAIN CONCERN HERE IS THAT MAY SEE PRECIP AREA SPLIT OFF TONIGHT AS CONVECTION GETS GOING AHEAD OF SFC WAVE FORMING OVER LWR MS VALLEY. POTENTIAL FOR THUNDER HERE VERY LIMITED. WILL KEEP MENTION IN NW OTHERWISE JUST GO WITH SHOWERS. BELIEVE ETA IS TOO FAST IN CLEARING FRONT OUT ON THU. PREFER AVN HERE. SFC WAVE RIDING UP ALONG FRONT SHOULD SLOW MOVEMENT ENOUGH TO KEEP MENTION OF PRECIP IN ALL BUT NW CWA THU. BEHIND FRONT FLOW QUICKLY BECOMES N/NE SO LK EFFECT DOES NOT APPEAR TO BE A FACTOR. GUIDANCE CLOSE AND REASONABLE ALL PERIODS FOR TEMPS. WILL STAY WITH FALLING TEMPS WORDING FOR THU. .IWX...NONE. JAL in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 245 AM CST WED MAR 15 2000 ...QUANDRY TODAY IS CHANCE FOR SNOW TONIGHT INTO EARLY THURSDAY... 00Z UPPER AIR HAND ANALYSIS SHOWED A VIGOROUS SHORT WAVE DIGGING INTO THE WEST SIDE OF THE UPPER TROUGH AS EVIDENCED BY 130+KT H3 JET STREAK OVER VANCOUVER ISLAND. AT H8 THE THERMAL GRADIENT ALONG THE CANADIAN, US BORDER INDICATED A STRONG ARCTIC FRONT WITH THE POALR FRONT BAROCLINIC ZONE FROM WYOMING ACROSS NEBRASKA TO SOUTHERN MINNESOTA. AT SURFACE THE LEE LOW IN CENTRAL COLORADO WAS FORCING SURFACE WIND ACROSS THE PLAINS TO REMAIN BACKED SOUTHEASTERLY AND DRAWING 50+ DEWPOINT AIR NORTH AND WEST OUT OF TEXAS AND OKLAHOMA. AT 06Z A 1007MB SURFACE LOW WAS MOVING OUT OF THE LEE SLOPES JUST NORTH OF LA JUNTA. ONLY THE RUC CAPTURED THIS FEATURE AND WILL BE USED FOR THE SHORT TERM OF THIS FORECAST. IN LATER PERIODS ALL THE MODELS ARE IN REASONABLE AGREEMENT WITH DIGGING THE UPPER WAVE INTO COLORADO BY 06Z THURSDAY AND THEN CLOSING AN H5 LOW OVER THE TEXAS PANHANDLE BY 18Z THURSDAY. THIS LEAVES KANSAS IN THE DEFORMATION ZONE ALONG WITH GOOD UPSLOPE BOUNDARY LAYER FLOW IN THE WAKE OF THE SURFACE FRONT. IT APPEARS THAT THE EVENT WILL START AS A COLORADO UPSLOPE EVENT IN THE NORTH CENTRAL FOOTHILLS THIS EVENING THEN SPREAD SOUTH DOWN THE FRONT RANGE BEHIND THE FRONT. AS THE UPPER SYSTEM COMES OUT OF THE ROCKIES TONIGHT SNOW SHOULD SPREAD EASTWARD ACROSS SOUTHEAST COLORADO AND INTO SOUTHWEST KANSAS AND THE PANHANDLES OF TEXAS AND OKLAHOMA. A WINTER STORM WATCH SEEMS IN ORDER FOR TONIGHT AND THURSDAY MORNING AND HAVE BASIC AGREEMENT FROM AMA...PUB...GLD... ICT AND OUN. THE MAIN PROBLEM WITH THIS SCENARIO WILL BE THE MOVEMENT OF THE FRONT. ONCE PRECIPITATION STARTS TODAY ALONG AND NORTH OF THE BOUNDARY EVAPORATIVE COOLING WILL REINFORCE THE COLD AIR A BIT AND THE MODELS CANNOT BE RELIED UPON TO IDENTIFY THIS LATENT HEAT EXCHANGE. FOR NOW WILL GUESS THE FRONT TO BE A BIT QUICKER THAN THE MODEL FORECASTS AND THUS ENDING UP A BIT FARTHER SOUTH TOO. THIS SHOULD SHUT OFF THE SNOW EVENT FOR MY AREA PRETTY EARLY ON THURSDAY. LOOKING AT PRECIPITABLE WATER AMOUNTS AND ADJUSTING FOR UPSLOPE AND DYNAMIC COOLING I ARRIVE AT TOTALS VERY CLOSE TO THE 4 TO 6 INCHES THE MODELS GENERATE FOR MY SOUTHWEST COUNTIES AND WILL PLAY THE FORECAST THAT WAY ALLOWING THE NEXT SHIFT SOME LATITTUDE AS THE SITUATION BECOMES MORE CLEAR CUT. GIVEN SNOW ACCUMULATION TONIGHT WILL SHADE OVERNIGHT LOWS UP A LITTLE FROM MOS AND COOL HIGHS ON THURSDAY A FULL CATEGORY IN ALL BUT MY FAR NORTHERN ZONES WHERE SNOWFALL WILL BE MINIMAL. PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE CONTAINED WITHIN THE DODGE CITY ZONE FORECAST. DDC 050/028 038/024 044 0++ GCK 050/027 038/023 044 0++ EHA 053/029 037/024 042 0++ LBL 053/029 037/025 042 0++ HYS 051/026 043/025 052 032 P28 057/031 040/028 050 088 .DDC...KSZ061>063-074>080-084>089 WINTER STORM WATCH TONIGHT AND EARLY THURSDAY. JOHNSON/SLEIGHTER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BISMARCK ND 335 PM CST TUE MAR 14 2000 VORT CENTER FORECAST BY RUC TO MOVE SOUTHEAST ACROSS SOUTH CENTRAL NORTH DAKOTA TONIGHT. FAST MOVING SYSTEM WILL SPREAD 2 TO 3 INCHES FROM THE NORTHWEST THROUGH EAST CENTRAL. ADVISORY CRITERIA IS MARGINAL BUT WILL GO WITH WINTER WEATHER ADVISORY. NOT GOING TO GET THE STRONG WINDS BEHIND THIS SYSTEM ON WEDNESDAY. INSTEAD...SFC HIGH WILL SLIDE SOUTH BEHIND LOW AND BRING CLLEAING SKIES WEDNESDAY. COLD NIGHT LIKELY WEDNESDAY NIGHT NORTH CENTRAL. THEN WARMUP THURSDAY AS H5 RIDGE BUILDS EAST OF NEXT SHORTWAVE. WILL KEEP CHC SNOW IN FRIDAY...WITH SAT AND SUNDAY MILD AND DRY. .BIS...TONIGHT...WINTER WEATHER ADVISORY...NORTHWEST THROUGH CENTRAL... ABELING nd SOUTHEAST TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 335 AM CST WED MAR 15 2000 AT 08Z...SHOWERS WERE REDEVELOPING OVER THE NORTHERN ZONES DUE TO WEAK LIFT AND LOW LEVEL SPEED CONVERGENCE. MDL GUIDANCE STILL PROJECTING HIGH POPS TODAY WITH RAIN CHANCES DECREASING BY AFTERNOON. LATEST RUC SHOWS RAPID DEVELOPMENT OF SHOWERS BY 12Z. LOOKING AT SATELLITE... STRONG S/WV IS STILL EVIDENT OVER NORTHERN MEXICO. FEEL THIS FEATURE WILL LIKELY TRIGGER ADDITIONAL SHOWERS AND THUNDERSTORMS TODAY. GREATEST 3 HR PRESSURE FALLS ARE OVER SOUTHEAST TEXAS WHICH FURTHER SUPPORTS THIS SCENARIO. PRIMARY CONCERN IS SUBSIDENCE CREATED BY CONVECTION OVER THE WESTERN GULF. THIS FEATURE MAY STABILIZE THE AIR MASS NEAR THE COAST. IN ADDITION... GUSTY EAST WINDS ARE ENTRAINING SLIGHTLY DRIER AIR INTO THAT REGION. WILL NOT REISSUE FLASH FLOOD WATCH TODAY DUE TO UNCERTAINTY ON WHERE (IF ANY) THE HEAVY RAIN AXIS WILL LIE. KHGX ESTIMATED PRECIPITATION TOTALS INDICATE 3 TO 5 INCHES OF RAIN OVER WHARTON...FT. BEND AND BRAZORIA COUNTIES. UPPER LEVEL DIVERGENCE INDUCED BY RRQ OF 80 KNOT SPEED MAX WILL WEAKEN AS THE JET MAX DEPARTS AND HIGHER PW VALUES WILL SHIFT EAST AS THE UPPER LEVEL TROUGH ALSO TRANSLATES EAST. THINK POPS CAN BE LOWERED SIGNIFICANTLY TONIGHT AS DYNAMICS WEAKEN/SHIFT EAST. AT 09Z...SURFACE ANALYSIS AND RADAR IMAGES SUGGEST SFC LOW PRESSURE HAS ADVANCED UP THE COAST BETWEEN PSX AND GLS. WINDS ALONG THE UPPER COAST WILL GRADUALLY WEAKEN AS THIS FEATURE SLOWLY MOVES NORTHEAST. WL TWEAK ZONES BASED ON RADAR COVERAGE AT TIME OF ZONE ISSUANCE BUT FEAR SUBSIDENCE IN THE WAKE OF GULF LOW WILL SQUASH POPS TODAY. NEXT IN A SERIES OF COLD FRONTS WILL APPROACH THE AREA LATE THURSDAY. FORECAST MODEL SOUNDINGS LOOK RATHER OMINOUS BY 00Z FRIDAY. LI'S ARE -3 TO -6 WITH TOTAL TOTALS IN THE 50S. ETA BEGINS TO POOL 1.2 INCH PW'S OVER THE REGION AND LAPSE RATES ARE 7.0 TO 7.5 DEGREES. UPPER LEVEL WIND FIELDS ARE RELATIVELY WEAK WHICH MAY NEGATE SEVERE POTENTIAL. WILL AWAIT SPC OUTLOOK BUT AM GETTING A LITTLE CONCERNED ABOUT SEVERE POTENTIAL LATE THURSDAY INTO THURSDAY NIGHT. WILL HAVE TO ADJUST FRIDAY FORECAST AS WELL. 72 HR AVN BRINGS A 50H LOW RIGHT OVER SE TX WITH ATTENDANT COLD POOL. 85H-70H LAYER RH IS MAXIMIZED AND MORE RAIN APPEARS LIKELY. CLOUDS AND STRONG CAA WILL KEEP HIGHS FRIDAY A BIT CHILLY. A BREAK SATURDAY WITH ANOTHER TROUGH DIGGING INTO THE SOUTHWESTERN U.S. SUNDAY PRODUCING ANOTHER CHANCE OF RAIN. THANKS TO CRP...LCH AND SHV FOR COORDINATION. .KHGX...SMALL CRAFT ADVISORY HIGH ISLAND TO FREEPORT 0-60 NM. ZONES. 43/42/48 PRELIMS.. CLL WT 070/059 076/043 058 5255 IAH WB 069/060 080/050 059 4245 GLS WB 071/065 073/058 060 5225 tx SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 255 AM MST WED MAR 15 2000 ...POTENTIAL FOR SIGNIFICANT SNOWFALL IN SOUTHEAST CO MOUNTAINS AND PLAINS MID AFTERNOON THROUGH TONIGHT... MODEL DISC: WHAT A DIFFERENCE A MODEL RUN MAKES! TIMING OF THE NEXT WEATHER EVENT HAS VERY GOOD RUN-TO-RUN CONTINUITY. HOWEVER...THERE HAS BEEN A SIGNIFICANT MODEL RUN SOLUTION CHANGE ON THE POSITION OF THE NEXT POTENTIAL WINTER STORM. CURRENT SHORT RANGE MODELS HAVE A FURTHER WEST AND SOUTH SOLUTION ON THE UPPER LEVEL STORM. BY THU AM...ETA IS MUCH FURTHER SOUTH IN NM WHILE AVN/NGM IS FURTHER NORTH ACROSS NORTHEASTERN NM. ETA PROBABLY TOO LIGHT IN THE OVERALL QUANTITY OF DEEP MOISTURE. AVN/NGM PRETTY MOIST LATER ON TNGT. GENERALLY...HAVE USED A PIECEMEAL MODEL SOLUTION ON WEATHER TRENDS. TDA: CURRENT WATER VAPOR IMAGERY SHOWED NEXT SYSTEM DRIVING THROUGH ID. 08Z/15 SURFACE ANALYSIS HAS FIRST COLD FRONT JUST GETTING INTO NORTHERN CO. SO FAR...HIGH CLOUD COVER AND WESTERLY SURFACE WINDS HAVE KEPT TEMPS UP IN THE UPPER 30S TO NEAR 50. WILL LOOK FOR FIRST COLD FRONT TO SLIDE SOUTHWARD AND PUSH UP AGAINST EASTERN FRONT RANGE BY THIS AFTERNOON. LATEST RUC HAS VIGOROUS MID-LEVEL SHORTWAVE TROUGH ENTERING NORTHWESTERN CO...WHICH WAS DEPICTED BY YESTERDAY'S MODEL RUNS. HOPE IT DOESN'T STAY ON A FURTHER NORTH TRACK...WHICH WOULD ALTER FORECAST. ULJ STILL DIGGING...SO MAY HAVE FURTHER DEEPENING OF SYSTEM. SHORTWAVE PROGGED TO PUSH INTO EASTERN UT/WESTERN CO BY 00Z/16 THU. 700MB LOW PROGGED TO DEVELOP IN CENTRAL CO BY 18Z/15 WED THAN MIGRATE SOUTHWARD. INITIALLY ACROSS SOUTHEAST CO MOUNTAINS AND PLAINS...LOW LEVEL TROP PROGGED TO BE RELATIVELY DRY...BUT SHOULD START TO MOISTEN UP BY LATE THIS AFTERNOON AS 30S SURFACE DEW POINTS ADVECTING WESTWARD. SIGNIFICANT AND DEEPENING UPSLOPE FLOW NOT ANTICIPATED UNTIL MID/LATE AFTERNOON. CLOUDS SHOULD BE LOWERING AND THICKENING ACROSS THE SOUTHEAST CO MOUNTAINS AND PLAINS. MOST OF THE PRECIPITATION WILL BE IN NORTHEASTERN CO THIS AFTERNOON THEN EXPAND SOUTHWARD LATER THIS AFTERNOON AND TNGT. WITH 700-500MB STATIC STABILITIES BECOMING MORE UNSTABLE...7-9 C/KM... SCATTERED SHOWERY PRECIPITATION LOOKS GOOD. 850-700MB THICKNESS STILL SUGGEST MAINLY LIQUID FOR THE PLAINS...EXCEPT MAYBE A MIX OR CHANGEOVER IN 71/72 AND SOUTHEAST MOUNTAINS. WILL NEED TO TWEAK POPS UP A BIT...ESPECIALLY IN 67/71/72. FOR SOUTHWEST/CENTRAL MOUNTAINS AND SAN LUIS VALLEY...LOOKS LIKE THE BEST COVERAGE IS FOR SAWATCH RANGE AND SHOULD REMAIN BELOW ADVISORY TYPE NUMBERS WITH UPSLOPE COMPONENT WEAKENING...COULDN'T RULE OUT LOCALLY HIGHER AMOUNTS IN HEAVIER SNOW SHOWERS. MAY NEED TO TWEAK TEMPS DOWN IN THE PLAINS GIVEN A FAVORED COOLER EASTERLY SURFACE WIND AND CLOUD COVER THIS AFTERNOON. TNGT: POTENTIAL FOR SIGNIFICANT SNOWFALL FOR SOUTHEAST MOUNTAINS AND PLAINS. IN RESPONSE TO VIGOROUS MID-LEVEL SHORTWAVE TROUGH DIVING INTO CENTRAL NM AND SURFACE CYCLOGENESIS IN SOUTHEAST NM/WEST CENTRAL TX...UPSLOPE FLOW TO DEEPEN AND STRENGTHEN IN EASTERN CO. THIS IS A TOTAL DIFFERENT SOLUTION THAN DEPICTED BY MODELS YESTERDAY. ANY FURTHER CHANGES COULD SIGNIFICANTLY ALTER SNOW AMOUNTS. MODERATE LARGE SCALE ASCENT...PER LAYER TOTAL Q(QS+QN)...AND A NEARLY ORTHOGONAL OROGRAPHIC FLOW ACROSS THE SOUTHEAST MOUNTAINS AND PLAINS SHOULD BE MAXED OUT. WITH SUCH INTENSE LIFT...WOULD BELIEVE STRONG DIABATIC COOLING WILL TAKE PLACE FOR PRECIPITATION CHANGEOVER IN THE PLAINS AND MOUNTAINS. 700MB TEMPS PROGGED TO DROP TO -8 TO -10 C WITH 070-090/20-30KTS WIND BY 06Z/16 THU. SNOW MODEL USUALLY UNDERESTIMATES ACTUAL SNOW EVENT FOR SOUTHEAST MOUNTAINS. IF EVERYTHING COMES TOGETHER...COULD SEE 8+ INCHES FOR SOUTHEAST MOUNTAINS WITH CUCHARA AND EAST FACING SLOPES OF WET MOUNTAINS POSSIBLY RECEIVING HIGHER AMOUNTS. IF DIABATIC COOLING WILL BE AS STRONG AS MODELS PREDICT...COULD SEE FAIRLY SIGNIFICANT SNOWFALL FOR THE PLAINS AND FOOTHILLS. ALL MODELS SNOW ALGORITHMS PREDICTING 6+ INCHES FOR THE PLAINS. JUST DEPENDS ON CHANGEOVER. WITH THE POTENTIAL BEING THERE...WILL ISSUE WINTER STORM WATCH FOR SOUTHEAST MOUNTAINS AND PLAINS FOR TNGT. HATE TO SINK MY TEETH INTO A 2ND PERIOD ADVISORY OR WARNING BASED ON ONLY ONE MODEL RUN. HOPEFULLY 12Z/15 WED MODEL RUNS WILL HAVE GOOD CONTINUITY WITH THIS RUN. THIS WILL GIVE THE DAYSHIFT ONE MORE MODEL RUN TO PROVIDE A MORE DETAILED WEATHER PICTURE. FOR SOUTHWEST/CENTRAL MOUNTAINS AND SAN LUIS VALLEY...DYNAMICAL FORCING SHOULD GENERATE AT LEAST SCATTERED SNOW SHOWERS. COULD RULE OUT SOME SIGNIFICANT SNOW BLOWING THROUGH LA VETA PASS TOWARDS FORT GARLAND. THU: DEPENDING ON WHICH MODEL YOU BELIEVE...THE STORM SYSTEM SHOULD BE PULLING AWAY FROM SOUTHEASTERN CO PLAINS EARLY THU MORNING. STILL A DEFORMATION ZONE CLOUD AND PRECIPITATION SHIELD THREAT FOR 77/81 EARLY THU MORNING...BUT OVERALL TREND WILL BE IMPROVING WEATHER CONDITIONS. MAX TEMPS WILL BE TRICKY DEPENDING ON HOW MUCH SNOW FALLS. PLAN TO GO JUST BELOW MOS TEMP GUIDANCE. EXTENDED(FRI-SUN): VERY QUICK LOOK AT NEW MRF REVEALS INTERESTING AND CHALLENGING PATTERN. POOR RUN-TO-RUN CONTINUITY. NOW...NEXT POTENTIAL WEATHER SYSTEM DOESN'T MAKE IT INTO CO AND CUTS OFF IN THE GREAT BASIN AND WONDERS INTO THE DESERT SOUTHWEST. STILL TRENDING WITH AN ACTIVE WEATHER PATTERN...THOUGH. NO CHANGES TO EFP. MUCH COORD WITH DEN/ABQ/GLD/DDC...THANKS A BUNCH! .PUB...WINTER STORM WATCH 67/71/72 FOR MID AFTERNOON THROUGH TONIGHT WINTER STORM WATCH 65/66/68/70/73>81 TONIGHT METZE co AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE DES MOINES IA 1010 AM CST WED MAR 15 2000 SHORT TERM... SURFACE TROUGH HAS PASSED THROUGH MIW-DSM-AIO LINE, WITH COLD FRONT NOT FAR BEHIND. DECENT PRESSURE RISES NOW IN NW IA WHICH SHOULD ALLOW FRONT TO CATCH UP WITH THE TROUGH SOON. CLEARING IS FAST APPROACHING THE NW CWA SO HAVE MENTION DECREASING CLOUDINESS IN THE NW. DENSE FOG IS LIFTING IN THE SE, ALLOWING FOR SOME SUN TO BREAK THROUGH, BUT ST DECK IS FAST APPROACHING RIGHT BEHIND TROUGH PASSAGE. ANOTHER ST DECK HAS FORMED BEHIND THE COLD FRONT AS WELL. CLOUDS WILL LIMIT SURFACE HEATING QUITE A BIT IN SE IA, BUT TOP AND OAX SOUNDINGS ARE SUPPORTIVE OF ELEVATED CONVECTION WHERE BEST 1000-850MB CONVERGENCE IS OCCURRING NEAR AND JUST BEHIND TROUGH. DECENT SHEAR AS WELL ALONG WITH LOW FZG LEVELS. PEA HAIL COVERED THE GROUND EARLIER THIS MORNING IN BOONE COUNTY, AND WOULDN'T BE SURPRISED TO SEE SMALL HAIL AGAIN LATER TODAY. RUC FORECAST SHOWS BEST 1000-850MB MOISTURE CONVERGENCE OVER SE IA INTO NORTHERN AND WEST CENTRAL MO BY 21Z. SHORTWAVE OVER SW KS IS SHEARING OUT, BUT THE ETA HAS CONTINUED WEAK TO MODERATE ISENTROPIC LIFT ALONG THE 295K SURFACE ABOVE THE LOW LEVEL COLD AIR THIS AFTERNOON. THIS SHOULD BE SUFFICIENT TO KEEP A COUPLE BANDS OF -SHRA IN CENTRAL ZONES BEHIND COLD FRONT. .DSM...NONE KULA ia AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND 856 AM MST WED MAR 15 2000 UPDATED ZONES TO INCLUDE WIND ADVISORY. FIRST FRONT HAS MOVED SOUTH OF THE AREA WITH HIGH PRESSURE AND ARCTIC AIR WELL TO THE NORTH. LATEST ETA SURFACE WINDS WHICH USUALLY RUN LOW INDICATE 25 TO 30 KNOTS LATER TODAY. RUCII ALSO INDICATING 25 TO 30 KNOTS AROUND 21Z WHICH WILL BE AROUND MAX HEATING. REMAINDER OF FORECAST LOOKS GOOD. .GLD...WIND ADVISORY IN EFFECT UNTIL 5 PM MST (6 PM CST) FOR ALL OF NORTHWEST KANSAS AND EXTREME SOUTHWEST NEBRASKA THEDE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1040 AM CST WED MAR 15 2000 FORECAST CONCERNS INVOLVE AFTERNOON TEMPERATURES AND SKY CONDITIONS... SATELLITE IMAGERY HAS SHOWN A RAPID CLEARING ACROSS THE NORTHERN CWA LAST FEW HOURS. THIS IS ASSOCIATED WITH STRONG LOW LEVEL COLD ADVECTION/SUBSIDENCE. 12Z RUC SOUNDINGS ACROSS CWA VIEWED IN BUFKIT INDICATED RAPID DRYING FOR THE REST OF TODAY. HAVE GONE WITH MOSTLY SUNNY FAR NORTH...AND CLEARING ELSEWHERE DURING THE AFTERNOON. WINDS SHOULD REMAIN UP AS ADIABATIC LAPSE RATE IS CONDUCIVE TO STRONG DOWNWARD MOMENTUM TRANSPORT. STRONG COLD ADVECTION SHOULD BE OFFSET BY STRONG MARCH INSOLATION. AFTERNOON TEMPERATURES SHOULD BE NEARLY STEADY FROM LATE MORNING READINGS. OF COURSE...NEAR THE IOWA BORDER THE TEMPERATURE WILL DROP A FEW DEGREES MORE AS THE CLOUD COVER LINGERS THERE FOR A TIME. 12Z ETA SHOWS CWA ON CYCLONIC SIDE OF UPPER JET MAX ON THURSDAY. LEFT IN MENTION OF SNOW FLURRIES...ALTHOUGH RELATIVE HUMIDITY PROGS DON'T SHOW MUCH IN THE WAY OF MOISTURE. .MSP...NONE. RJN mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 845 PM CST TUE MAR 14 2000 00Z RUC AND 00Z ETA HAVE COME INTO AGREEMENT ON A QUICK SHOT OF SNOW ACROSS CENTRAL MN. ISENTROPIC ANALYSIS FROM 18Z ETA HAD ALSO SHOWN 2 TO 3 GRAMS OF MOISTURE ON THE 290 SURFACE WORKING TOWARD CENTRAL MN. QUITE A TIGHT THERMAL BOUNDARY ACROSS THIS AREA. A LITTLE CONCERNED ABOUT THE SPEED OF SYSTEM NOT ALLOWING FOR BIG ACCUMULATIONS BUT THINK AMOUNT OF LIFT WILL BE ENOUGH. A DECENT AMOUNT OF 200 MB WARM ADVECTION ALSO INDICATED. AFTER COORD WITH DLH WILL GO WITH AN ADVISORY FOR 4 NORTHERN COUNTIES LATE TONIGHT THROUGH EARLY MORNING. FARTHER SOUTH..MORE SPOTTY PRECIP BUT CONDITIONS BECOME A BIT UNSTABLE IN THE SOUTH WITH SOME SATURATED EPV SHOWING UP AT 600 MB AND UNSTABLE LAPSE RATES ACROSS S MN. WILL MENTION SOME SHOWERS..AND WOULD'T RULE OUT SOME THUNDER. .MSP...SNOW ADVISORY LATE TONIGHT AND WEDNESDAY MORNING FOR TODD..MORRISON..MILE LACS AND KANABEC COUNTY. RICHARDSON mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 444 AM CST WED MAR 15 2000 STLT LOOP..MTR DATA AND LAST NITE'S 850 HPA ANLYS INDICATE WEAK BNDRY IN LWR TROPOSPHERE STILL DRAPED ACR NRN THIRD OF CWA. SHWRS AND ISOLD THNDR WHICH FORMED TO N OF THIS BNDRY TUE/TUE EVNG HAS FINALLY VACATED CWA TO E. HOWEVER AREAS OF ST/FG STILL RMN WITH LOCAL VSBYS BEING REPORTED IN 1-2SM RANGE. INSERTED FG FOR ERLY THIS AM ACR NRN THIRD ZNS. PROFILER DATA INDICATES A MARGINAL PUSH TO SWEEP AFOREMENTIONED BNDRY AWAY FM FCST AREA AT 925/850 HPA LVL BUT WILL HAVE TO WAIT UNTIL SFC GRADIENT INCRS LTR THIS AM AS INTERVALS OF SUN MIX WNDS DOWNWARD. RUC CONTS TO FCST INCR IN MSTR FLUX CNVGNC AFTER 1500 UTC ACR WRN CWA AND AFT 1800 UTC IN E. MAPS DATA CONTS TO SHW THETA E RDG NOSING NEWRD INTO ALL OF CWA XCPT XTRM NW MO. WENT WITH CHC POPS ALL ZNS TDY AND DROPPED MENTION OF PM ONLY AND KEPT THNDR ALL ZNS BUT XTRM NW. TEMPS VRY TRICKY TDY. WITH BROADER CLD CVR ACR N USED MID/UPPR 50S WHICH IS A CAT LWR THAN PREV FCST BUT IN SRN TWO THIRDS INTERVALS OF SUN SHLD PROVIDE FOR WIDER RANGE SO OPENED OF 5 DEG RANGES DOWNWARD ALG AND S OF MO RVR. IN BIGGER PICTURE STG 135 KT 300 HPA JET DRIVING INTO NW U.S. THIS AM. WV LOOP THRU 0900 UTC SHOWED JET SPLITTING WITH PORTION HEADING EWRD ACR MT AND NRN PLNS AND REMAINDER DROPPING FTHR S IN GRT BASIN RGN. NGM/ETA SEEM TO HAVE DECENT HNDL ON THIS FEATURE AND CORESPONDING H5-H1 POTENTIAL VORTICITY FCST THRU 1200 UTC THUR SUGGEST GREATEST POTENTIAL VORTICITY ADVT PERSISTING FM NRN UT AND ACR CNTL ROCKIES WHICH SHLD AID STG CYCLOGENESIS FM TX PNHDL NWRD INTO SW KS. THIS IS FTHR S THAN TUE MODEL RUNS WHICH SUGGEST PCPN THREAT FTHR S TNGT THRU THUR. COLDEST AMS SINCE LATE JAN POISED TO ENTER CONUS NXT 24 HRS. MODELS HAVE FINALLY PICKED UP ON STRENGTH AND QUICKER ACCELERATION OF ARCTIC AMS TO S. LEADING EDGE ALREADY THRU NRN SD AND SEE NO REASON TO DEVIATE FM ETA/NGM SOLN OF PUNCHING CD AIR INTO XTRM NW MO BET 0000-0600 UTC AND REST OF FCST AREA BY 1200 UTC THUR. WITH PREVIOUSLY MENTIONED SFC WV TRACKING ACR SRN/CNTL PLNS ERLY THUR FRZN PCPN NOW A CONCERN FOR CWA. KEPT CHC POPS FOR -RA ALL ZNS FOR TNGT THEN INTRODUCED -SN LATE THIS EVNG NW AND CLOSER TO DAYBRK SE. WITH ANTICIPATED STRENGTH OF CAA IT APPRS ATTM THAT THREAT FOR SGFNT FRZN PCPN SHLD BE DISPLACED S OF FCST AREA. DAY CREW WILL HAVE TO CLOSELY RE-EXAMINE SITUATION WITH NXT MODEL RUN. NONE THE LESS TRIMMED TEMPS DOWNWARD TNGT AND THUR STAYING A BIT CLOSER TO FWC NUMBERS. CRNT XTND FCST LKS GOOD IN TIMING OF NXT SVRL SYSTEMS BUT MAY BE A TAD SLOW IN WARMING THINGS UP IN LTR PRDS. WITHOUT MUCH TIME TO LK AT LATEST MED RANGE DATA OPTED TO MAKE NO CHGS FOR NOW. .EAX...NONE. BODNER mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 955 AM EST WED MAR 15 2000 HIGH PRES KEEPS A STRONG HOLD ACRS SE U.S. HIGH CNTRD ACRS ERN NC WTH RDGG S THRU ERN SC TO THE NRN FL CST. ANOTHER DAY OF THIN CI CLDS... BUT CHNGS IN STORE OVR NXT FEW DAYS. UNTIL THEN...WL BE ANOTHER GREAT DAY WXWISE. PLAN ON GOING WTH MORE OPTIMISTIC MSTLY SUNNY VS. PTLY CLDY IN CRNT ZNS. LGT WNDS ERLY THIS MRNG BEGINNING TO COME ARND TO SE. WL BRNG THAT CRNT. TEMP FCST LOOKS GOOD BASED ON EXTRAPOLATION OF H85 TEMPS FM 12Z SOUNDINGS. ONLY CHNG TO TEMPS WL BE ALNG SC CST...RUNNING COOLER WTH WATER TEMPS ONLY IN LWR 60S...SO WL BACK OFF FM 65-70 TO MID 60S. CWF...MINOR WORDING CHGS TO UPDATE COASTAL WATERS FOR THIS AFTERNOON. MESOETA AND RUC BOTH INDICATING WINDS BECMG E WITH SLIGHTLY HIGHER WINDS OVER GA WATERS THAN SC WATERS. .CHS... SC...NONE. GA...NONE. EVT/SLB sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 925 AM EST WED MAR 15 2000 WESTERN GULF COAST SYSTEM SHOULD CONTINUE TO SPREAD MID-HI CLOUDS OUR WAY THIS AFTERNOON. HOWEVER...PCPN WITH THIS SYSTEM SHOULD STAY MAINLY WELL TO OUR SW... AS 12Z RUC MODEL CONFIRMS. SOME BREAKS OF SUNSHINE AT TIMES EVEN IN SE TN/SW NC...BUT SKY CONDITION FORECAST LOOKS BASICALLY ON TRACK. 12Z BNA SOUNDING EASILY SUPPORTS MAX TEMPS OF UPR 60S/NEAR 70...IN LINE WITH ONGOING HIGH TEMPS. NO APPARENT REASON TO UPDATE ZONES AT THIS TIME. .MRX... NC...NONE. TN...NONE. VA...NONE. TG tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME...ISSUED BY NWSFO CAR 930 AM EST WED MAR 15 2000 AWIPS BACKUP TEST IN EFFECT UNTIL 1 PM. PUBLIC...COLD FRONT CURRENTLY OVER THE ST. LAWRENCE VALLEY. CURRENT RUC ONLY SHOWS A SLIGHT SOUTHWARD DRIFT BY THIS FRONT THIS AFTERNOON. CURRENT VIS SATL PICS SHOW AREA OF CLOUDS WITH FRONT MOVING ESE. CANADIAN RADARS SHOW A LINE OF -SHRA/-SHSN WITH AND JUST AHEAD OF THE FRONT. THIS WOULD SUPPORT THE CURRENT FORECAST OF SCT -SHRN/- SHSN OVER THE WRN MTNS OF ME AND COOS COUNTY NH. WOULD EXPECT ANY -SHSN TO BE CONFINED TO THE HIGHER ELEVATIONS...WITH SCT -SHRA OVER THE LOWER TERRAIN. OVER THE REST OF THE FORECAST AREA NOT MUCH IN THE WAY OF PRECIP...ALTHOUGH RADARS UPSTREAM SHOW A FEW "SPRINKLES". WILL THUS MAINTAIN THESE IN AFTERNOON FCST. OTHERWISE...ANY SUN WILL GIVE WAY TO CLDS AS MID LEVEL MOISTURE MOVES IN FROM THE WEST. CURRENT TEMPS STARTING TO REBOUND AND PREVIOUS FCST TEMPS LOOK GOOD. WILL LOOK AT 10 AM OBS TO DETERMINE IF ANY ADJUSTMENTS ARE NEEDED. MARINE...CURRENT OBS HAVE WINDS/WAVES A LITTLE LOWER THEN FCST... HOWEVER RUC WINDS SHOW BOUNDARY LAYER WINDS TO STRENGTHEN THIS AFTERNOON. THUS DO'T ANTICIPATE ANY MAJOR ADJUSTMENTS. .GYX...GLW. LULOFS me FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 700 AM CST WED MAR 15 2000 MAIN RISE/FALL PRESSURE COUPLET AND STRONGEST CAA DEPICTED BY MSAS NOW SOUTH/SOUTHEAST OF FA. AS A RESULT WINDS NOT COMING UP AS EXPECTED. RUC ALSO RELAXES SFC GRADIENT AND SFC WIND SPEED THROUGH MID MORNING. RETURNS FROM KMVX-88D ALSO DIMINISHING SIGNIFICANTLY WITH AREA VSBYS IMPROVING. SO WHILE BLSN/DRSN EXPECTED IN OPEN COUNTRY DO NOT BELIEVE VSBY WILL SERIOUSLY HAMPER TRAVEL IN SNOW BAND. AS A RESULT WILL CANCELL CURRENT ADVISORY OVR SOUTHERN FA. .FGF...NONE. VOELKER nd