AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 935 PM CST THU JAN 6 2005 .DISCUSSION... LARGE STRATUS DECK CONTINUES TO ENVELOP THE CWA FROM SOUTH TO NORTH. TEMPS JUMP WELL INTO THE TEENS WITH THE ARRIVAL OF THE CLOUDS. ALSO SOME FLURRIES BEING REPORTED. WILL SEND ANOTHER ZONE UPDATE MAINLY TO FRESHEN WORDING. BACK EDGE OF STRATUS LIFTING NORTH THROUGH MISSOURI BUT AWIPS DISTANCE/SPEED TOOL KEEPS THIS JUST SOUTH OF CWA OVERNIGHT. THEREFORE...OVERNIGHT EXPECT CLOUDY/MOCLDY SKIES WITH TEMPS STEADY IN THE TEENS. ..05.. && .PREVIOUS DICSUSSION... .SYNOPSIS... DEPARTING WINTER STORM WELL OUT OF AREA OVER EASTERN GREAT LAKES WITH RIDGE OF HIGH PRESSURE AT SURFACE OVER SOUTHERN PLAINS POKING NORTH INTO CENTRAL IA EARLY THIS AFTERNOON. BACK EDGE OF UPPER COMA CLOUDS AND WEAK SURFACE CONVERGENCE ALONG LOW LEVEL TROUGH HAVE KEPT FLURRIES GOING INTO EARLY AFTERNOON OVER NW IL. UPSTREAM...AN UPPER LEVEL POSITIVE TILT TROUGH WAS MOVING THROUGH CENTRAL ROCKIES. FRESH SNOW COVER LIMITING AFTERNOON TEMPS TO TEENS AND LOWER 20S OVER CWA...WITH ONLY SINGLE DIGITS UPSTREAM IN CENTRAL AND NW IA. && .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)...MAIN CHALLENGE IS TEMPERATURES. RIDGE AXIS PROGGED TO SHIFT EAST OVER CWA THIS EVENING WITH STAGE SET FOR EARLY TEMPERATURE PLUNG BEFORE WEAK LOW LEVEL WARM AIR ADVECTION ENDS THE FALL OR ALLOWS SLIGHT RISE TOWARD MORNING. SOME CONCERN THAT LOW CLOUD FIELD THAT DEVELOPED UNDER RIDGE IN PARTIAL SNOW OR ICE COVERED AREAS OF KS AND MO MAY CONTINUE TO INCH NORTHWARD. HOWEVER...THESE CLOUDS FORMED IN AN AREA WITH LOW CONVECTIVE TEMPS THIS AFTERNOON AND WEAK ISENTROPIC IN RETURN FLOW ABOVE THE SURFACE HIGH. WITH VISIBLE IMAGERY SHOWING THESE CLOUDS TO BE RATHER THIN...WILL DISCOUNT THEM FOR FIRST HALF OF TONIGHT FOR ALL BUT FAR SOUTH. MOS GUIDANCE MINS FOR TONIGHT ARE CLOSE TO CURRENT OBS OVER MUCH OF CWA AND THUS DISCOUNTED. WENT CLOSER TO A BLEND OF META AND RUC SURFACE TEMPERATURES WITH RAPID PLUNGE AFTER SUNSET TO SUB ZERO READINGS IN DEEPEST SNOW COVERED EAST CENTRAL IA...WITH SINGLE DIGITS TO NEAR 12 IN SOUTHEAST. SOME MID AND HIGH CLOUDS...ALONG WITH LOW LEVEL RETURN FLOW...WILL THEN KEEP TEMPS STEADY OR POSSIBLY RISE A COUPLE DEGREES BY MORNING. ON FRIDAY...THE UPPER TROUGH PUSHES THROUGH BY EVENING WITH MAIN VORT CENTER PASSING ACROSS NORTHERN MO TO CENTRAL IL. WARM ADVECTION AND WEAK ISENTROPIC LIFT INCREASES AHEAD OF THIS FEATURE THROUGH DAY AND SHOULD RESULT IN MOSTLY CLOUDY SKIES. GFS MORE BULLISH WITH ISENTROPIC LIFT IN SE CWA AND THUS PRODUCES QPF BY EVENING WHILE OTHER SHORT RANGE MODELS KEEP CWA DRY. WILL GO WITH SLIGHT CHANCE POPS IN SE FOR LATE AFTERNOON AND EVENING FOR LIGHT SNOW WITH FLURRIES POSSIBLE ELSEWHERE. MOS GUIDANCE STILL TOO WARM FRIDAY AND UNDERCUT BY A COUPLE CATEGORIES NORTH AND A FEW DEGREES BELOW COLDEST MAV IN SOUTH WITH HIGHS RANGING FROM AROUND 20 NORTH TO LOWER 30S SOUTH WHERE ICE AND SNOW COVER THINNEST. EXPECT CLEARING TREND AS SHORTWAVE UPPER RIDGE MOVES OVERHEAD WITH TEMPS PLUNGING INTO SINGLE DIGITS AND TEENS...WELL BELOW COLDEST MAV GUIDANCE. ..SHEETS.. && .LONG TERM...(SATURDAY THROUGH MONDAY NIGHT)... MAIN CONCERN THROUGH THE WEEKEND WILL BE TEMPS WITH FLAT WSW UPPER FLOW AND SURFACE RIDGE DEPARTING REGION SATURDAY...SETTING UP WEAK RETURN FLOW SATURDAY NIGHT AND SUNDAY. MODELS DROP ANOTHER WEAK FRONT THROUGH THE REGION MONDAY. OF COURSE WITH SNOW COVER OVER MOST OF CWA WILL BE GOING NEAR OR UNDER COOLER MET NUMBERS SATURDAY/SATURDAY NIGHT. LIMITED MIXING ASSOCIATED WITH LIGHT WINDS NEAR THE SURFACE SATURDAY WILL ALSO LIMIT TEMP RECOVERY...IN ADDITION TO THE SNOW COVER. WEAK SLY FLOW SETS UP SUNDAY AHEAD OF SURFACE LOW MOVING ACROSS THE NCNTRL U.S. THE LOW DRAGS A WEAK COLD FRONT SOUTH THROUGH CWA EARLY MONDAY. THE GFS IS SHOWING SOME FORCING ASSOCIATED WITH FRONTOGENESIS AND S/W ENERGY MOVING ALONG THE BOUNDARY. AMOUNT OF MOISTURE MAY BE THE BIG ISSUE WITH ANY PCPN DEVELOPMENT. 12Z GFS RUN WAS SHOWING A NARROW SWATH OF 90 PCT H8 RH JUST N OF THE BOUNDARY BY 18Z...SO INTRODUCED LOW POPS FOR THE ENTIRE AREA. TEMP PROFILES 18Z MONDAY FAVOR RA IN THE SOUTH WHILE COLDER H8 TEMPS N SUGGEST A MIX IS POSSIBLE. (TUESDAY THROUGH THURSDAY)... LOOKS LIKE AN ACTIVE PERIOD THROUGH THE MIDDLE OF NEXT WEEK. GFS/ECMWF/UKMET IN REASONABLE AGREEMENT KEEPING SW FLOW OVER REGION WITH ZONAL FLOW OVER SRN CANADA HOLDING COLDER AIRMASS WELL TO THE NORTH. THE 06/00Z GFS LOOKS LIKE IT IS TRYING TO PHASE THE TWO STREAMS WEDNESDAY BRINING MORE ENERGY DOWN THE EAST SIDE OF THE ERN PAC RIDGE THAN THE EUROPEAN MODELS WHICH KEEP THE SPLIT FLOW INTACT THROUGH MID WEEK. THE 06/12Z GFS AT 108HR IS A LITTLE SLOWER WITH THIS PIECE OF ENERGY...SUPPORTING THE EUROPEAN MODELS SOLUTION. WILL TREND TOWARD THE ECMWF SOLUTION WITH STRONG BAROCLINIC ZONE...ENHANCED BY SNOWFIELD...SETTING UP OVER THE MID MISSISSIPPI VALLEY BY WEDNESDAY. WITH SW FLOW IN PLACE AND STRONG BAROCLINIC ZONE OVER CWA WILL CONTINUE CHANCE POPS ALREADY IN FCST FOR TUESDAY THROUGH THURSDAY. INITIALLY PCPN WILL BE RAIN IN THE SOUTH. NRN SECTIONS WILL LIKELY SEE A MIX OF PCPN TUESDAY NIGHT AND WEDNESDAY AS DEEP SNOW COVER ALTERS TO THE LOW LEVEL TEMP PROFILE. GRIDS CURRENTLY HAVE R/S...BUT AS WE DRAW CLOSER TO THE EVENT WOULD SUSPECT THAT THIS WILL TREND TOWARD FREEZING RN/DZ WITH ALL MODELS SHOWING WARM AIR AT H850. PCPN CWA WIDE TO CHANGE TO SNOW BY THURSDAY AS NRN AND SRN STREAMS PHASE...ALLOWING COLD CANADIAN AIR TO SURGE SOUTH OVER THE REGION. WITH SNOW IN PLACE...KEPT TEMPS BELOW MEX NUMBERS...ESPECIALLY IN THE NORTH. ...DLF... && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SHEETS/DLF ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 718 PM CST THU JAN 6 2005 .DISCUSSION... && .UPDATE... UPDATED EARLY THIS EVE TO ACCT FOR CLD TRENDS AND SOME TEMPS WHICH HAVE PLUMMETED OVR MSTLY CLR SKIES AND FRESH DEEP SNW COVER. READINGS ALREADY SVRL DEGS BLO ZERO AT AMW/MCW. NEITHER MOS NOR RAW MDL TEMPS SEEM TO BE HANDLING THIS WELL. MOS TOO WRM AND RAW MDL TEMPS GOING TOO COOL BECAUSE THEY DO NOT APPR TO BE AGGRESSIVE ENOUGH WITH SERN IA AND MO STRATUS. THUS DROPPED COOL SPOTS SVRL MORE DEGS THRU 06Z THEN GRDL RISE AS WRM ADVCTN INCRS IN LOWEST 100 MB PER LATEST RUC. KEPT TEMPS STEADY OR SLOWLY RISING INVOF STRATUS. NOT THE GREATEST CONFIDENCE WITH THIS MUCH VARIABILITY ATTM. CLD WISE MDLS SEEM TO BE UNDERESTIMATING LOW CLD POTENTIAL. STRATUS SHOULD CONTINUE TO ADVECT NWD AS RDG APCHS AND CROSSES MS RVR. NR SFC TEMPS NR START OF DENDRETIC LYR SO OCNL FLURRIES NOTED IN A FEW OBS SEEM REASONABLE AND WL CARRY ISOLD MENTION TNGT WHERE ST IS XPCD. WL ALSO KEEP AREAS OF FOG GOING AS LOW LVL MSTR GRDLLY INCRS OVR SNW FIELD. && .PREV DISCUSSION...400 PM NOT AS MANY ISSUES AS THE SEVERAL PREVIOUS FORECAST BUT STILL NOT AS SIMPLE AS IT MAY SEEM. CURRENTLY...SFC RIDGE SLIDING THROUGH CENTRAL IOWA WITH AMPLE SUNSHINE IN MOST AREAS ALTHOUGH SOME LOW CLDS HAVE DEVELOPED IN THE SOUTH PRODUCING A FEW FLURRIES. TEMPS STRUGGLED TO GET VERY FAR TODAY AS AMPLE NEW SNOWCOVER KEPT HEATING IN CHECK. SHORT TERM...APPEARS LOWS TO OCCUR THIS EVENING BEFORE STRONGER WARM ADVECTION KICKS IN LATER TONIGHT. IN ADDITION...APPEARS LOW STRATUS SHOULD ADVECT NORTH FROM KANSAS AND INTO THE STATE DURING THE OVERNIGHT HELPING TEMPS TO RECOVER FROM EVENING LOWS. ON FRIDAY...UPPER LOW WILL MOVE TOWARD IOWA WITH THERMAL RIDGE CROSSING THE STATE. FORCING ASSOCIATED WITH THE LOW WILL BE WORKING WITH LITTLE MOISTURE...THEREFORE CLOUDS ARE THE MAIN ISSUE WITH THIS SYSTEM AS IT PASSES THROUGH IOWA. AS FOR TEMPS...FRESH SNOW COVER AND PARTLY TO MOSTLY CLOUDY SKIES SHOULD GENERALLY LIMIT HEATING AND STAYED ON COOL SIDE OF GUIDANCE. THE PASSING OF THE WAVE FRIDAY NIGHT WILL BE FOLLOWED BY SFC RIDGING AS SOME CLEARING BY THE EARLY MORNING HOURS. EXPECT TEMPS TO DROP QUICKLY IN THIS SCENARIO AND HAVE GONE AT OR BELOW THE COOL MET GUIDANCE. OBVIOUSLY...ANY CLOUDS OR HIGHER WINDS WL BUST THIS FORECAST. STRONG WAA TO ENSUE ON SATURDAY INTO SUNDAY AS HEIGHTS RISE ACROSS THE CENTRAL US. TEMPS THE PRIMARY CONCERN DURING THIS PERIOD AS SNOW AND CLOUDS WL PRESENT PROBLEMS. NICE THERMAL RIDGE IN PLACE BY SUNDAY WITH MEX GUIDANCE SUGGESTION MID 50S. GIVEN TIME OF YEAR AND DEPTH OF SNOW...HAVE SCRAPPED THAT FOR MUCH COOLER READINGS. EXTENDED FORECAST WL SEE WESTERN TROF EVENTUALLY MOVE EAST BY MID TO LATE WEEK. EXPECT INCREASING THREAT FOR PRECIPITATION STARTING EARLY TUESDAY AND CONTINUING UNTIL COLD PLUNGE BY THURSDAY OF NEXT WEEK. OTHERWISE...TEMPS WL BE WAFFLING AROUND THE FREEZING MARK WITH THE THREAT OF VARIOUS PCPN TYPES A DEFINITE PROBLEM UNTIL FRONT ARRIVES. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ COGIL/SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 700 PM CST THU JAN 6 2005 .DISCUSSION... SENT QUICK ZONE UPDATE FOR CLOUD/TEMP TRENDS. INCREASED CLOUD COVER TONIGHT...AS SATELLITE SHOWS LOW CLOUDS (MVFR CIGS) IN SOUTHEAST IA LIFTING NORTH WITH LLVL FLOW INCREASING FROM THE SOUTH ON BACKSIDE OF RIDGE. SOME FLURRIES BEING WRUNG OUT WITH THE LOW CLOUDS SO ADDED MENTION AS WELL. TEMPS CRASHING NORTH SO ADJUSTED DOWN A FEW DEGS AND BUMPED UP MINS IN THE SOUTH DUE TO THE CLOUDS. ..05.. && .PREVIOUS DICSUSSION... .SYNOPSIS... DEPARTING WINTER STORM WELL OUT OF AREA OVER EASTERN GREAT LAKES WITH RIDGE OF HIGH PRESSURE AT SURFACE OVER SOUTHERN PLAINS POKING NORTH INTO CENTRAL IA EARLY THIS AFTERNOON. BACK EDGE OF UPPER COMA CLOUDS AND WEAK SURFACE CONVERGENCE ALONG LOW LEVEL TROUGH HAVE KEPT FLURRIES GOING INTO EARLY AFTERNOON OVER NW IL. UPSTREAM...AN UPPER LEVEL POSITIVE TILT TROUGH WAS MOVING THROUGH CENTRAL ROCKIES. FRESH SNOW COVER LIMITING AFTERNOON TEMPS TO TEENS AND LOWER 20S OVER CWA...WITH ONLY SINGLE DIGITS UPSTREAM IN CENTRAL AND NW IA. && .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)...MAIN CHALLENGE IS TEMPERATURES. RIDGE AXIS PROGGED TO SHIFT EAST OVER CWA THIS EVENING WITH STAGE SET FOR EARLY TEMPERATURE PLUNG BEFORE WEAK LOW LEVEL WARM AIR ADVECTION ENDS THE FALL OR ALLOWS SLIGHT RISE TOWARD MORNING. SOME CONCERN THAT LOW CLOUD FIELD THAT DEVELOPED UNDER RIDGE IN PARTIAL SNOW OR ICE COVERED AREAS OF KS AND MO MAY CONTINUE TO INCH NORTHWARD. HOWEVER...THESE CLOUDS FORMED IN AN AREA WITH LOW CONVECTIVE TEMPS THIS AFTERNOON AND WEAK ISENTROPIC IN RETURN FLOW ABOVE THE SURFACE HIGH. WITH VISIBLE IMAGERY SHOWING THESE CLOUDS TO BE RATHER THIN...WILL DISCOUNT THEM FOR FIRST HALF OF TONIGHT FOR ALL BUT FAR SOUTH. MOS GUIDANCE MINS FOR TONIGHT ARE CLOSE TO CURRENT OBS OVER MUCH OF CWA AND THUS DISCOUNTED. WENT CLOSER TO A BLEND OF META AND RUC SURFACE TEMPERATURES WITH RAPID PLUNGE AFTER SUNSET TO SUB ZERO READINGS IN DEEPEST SNOW COVERED EAST CENTRAL IA...WITH SINGLE DIGITS TO NEAR 12 IN SOUTHEAST. SOME MID AND HIGH CLOUDS...ALONG WITH LOW LEVEL RETURN FLOW...WILL THEN KEEP TEMPS STEADY OR POSSIBLY RISE A COUPLE DEGREES BY MORNING. ON FRIDAY...THE UPPER TROUGH PUSHES THROUGH BY EVENING WITH MAIN VORT CENTER PASSING ACROSS NORTHERN MO TO CENTRAL IL. WARM ADVECTION AND WEAK ISENTROPIC LIFT INCREASES AHEAD OF THIS FEATURE THROUGH DAY AND SHOULD RESULT IN MOSTLY CLOUDY SKIES. GFS MORE BULLISH WITH ISENTROPIC LIFT IN SE CWA AND THUS PRODUCES QPF BY EVENING WHILE OTHER SHORT RANGE MODELS KEEP CWA DRY. WILL GO WITH SLIGHT CHANCE POPS IN SE FOR LATE AFTERNOON AND EVENING FOR LIGHT SNOW WITH FLURRIES POSSIBLE ELSEWHERE. MOS GUIDANCE STILL TOO WARM FRIDAY AND UNDERCUT BY A COUPLE CATEGORIES NORTH AND A FEW DEGREES BELOW COLDEST MAV IN SOUTH WITH HIGHS RANGING FROM AROUND 20 NORTH TO LOWER 30S SOUTH WHERE ICE AND SNOW COVER THINNEST. EXPECT CLEARING TREND AS SHORTWAVE UPPER RIDGE MOVES OVERHEAD WITH TEMPS PLUNGING INTO SINGLE DIGITS AND TEENS...WELL BELOW COLDEST MAV GUIDANCE. ..SHEETS.. && .LONG TERM...(SATURDAY THROUGH MONDAY NIGHT)... MAIN CONCERN THROUGH THE WEEKEND WILL BE TEMPS WITH FLAT WSW UPPER FLOW AND SURFACE RIDGE DEPARTING REGION SATURDAY...SETTING UP WEAK RETURN FLOW SATURDAY NIGHT AND SUNDAY. MODELS DROP ANOTHER WEAK FRONT THROUGH THE REGION MONDAY. OF COURSE WITH SNOW COVER OVER MOST OF CWA WILL BE GOING NEAR OR UNDER COOLER MET NUMBERS SATURDAY/SATURDAY NIGHT. LIMITED MIXING ASSOCIATED WITH LIGHT WINDS NEAR THE SURFACE SATURDAY WILL ALSO LIMIT TEMP RECOVERY...IN ADDITION TO THE SNOW COVER. WEAK SLY FLOW SETS UP SUNDAY AHEAD OF SURFACE LOW MOVING ACROSS THE NCNTRL U.S. THE LOW DRAGS A WEAK COLD FRONT SOUTH THROUGH CWA EARLY MONDAY. THE GFS IS SHOWING SOME FORCING ASSOCIATED WITH FRONTOGENESIS AND S/W ENERGY MOVING ALONG THE BOUNDARY. AMOUNT OF MOISTURE MAY BE THE BIG ISSUE WITH ANY PCPN DEVELOPMENT. 12Z GFS RUN WAS SHOWING A NARROW SWATH OF 90 PCT H8 RH JUST N OF THE BOUNDARY BY 18Z...SO INTRODUCED LOW POPS FOR THE ENTIRE AREA. TEMP PROFILES 18Z MONDAY FAVOR RA IN THE SOUTH WHILE COLDER H8 TEMPS N SUGGEST A MIX IS POSSIBLE. (TUESDAY THROUGH THURSDAY)... LOOKS LIKE AN ACTIVE PERIOD THROUGH THE MIDDLE OF NEXT WEEK. GFS/ECMWF/UKMET IN REASONABLE AGREEMENT KEEPING SW FLOW OVER REGION WITH ZONAL FLOW OVER SRN CANADA HOLDING COLDER AIRMASS WELL TO THE NORTH. THE 06/00Z GFS LOOKS LIKE IT IS TRYING TO PHASE THE TWO STREAMS WEDNESDAY BRINING MORE ENERGY DOWN THE EAST SIDE OF THE ERN PAC RIDGE THAN THE EUROPEAN MODELS WHICH KEEP THE SPLIT FLOW INTACT THROUGH MID WEEK. THE 06/12Z GFS AT 108HR IS A LITTLE SLOWER WITH THIS PIECE OF ENERGY...SUPPORTING THE EUROPEAN MODELS SOLUTION. WILL TREND TOWARD THE ECMWF SOLUTION WITH STRONG BAROCLINIC ZONE...ENHANCED BY SNOWFIELD...SETTING UP OVER THE MID MISSISSIPPI VALLEY BY WEDNESDAY. WITH SW FLOW IN PLACE AND STRONG BAROCLINIC ZONE OVER CWA WILL CONTINUE CHANCE POPS ALREADY IN FCST FOR TUESDAY THROUGH THURSDAY. INITIALLY PCPN WILL BE RAIN IN THE SOUTH. NRN SECTIONS WILL LIKELY SEE A MIX OF PCPN TUESDAY NIGHT AND WEDNESDAY AS DEEP SNOW COVER ALTERS TO THE LOW LEVEL TEMP PROFILE. GRIDS CURRENTLY HAVE R/S...BUT AS WE DRAW CLOSER TO THE EVENT WOULD SUSPECT THAT THIS WILL TREND TOWARD FREEZING RN/DZ WITH ALL MODELS SHOWING WARM AIR AT H850. PCPN CWA WIDE TO CHANGE TO SNOW BY THURSDAY AS NRN AND SRN STREAMS PHASE...ALLOWING COLD CANADIAN AIR TO SURGE SOUTH OVER THE REGION. WITH SNOW IN PLACE...KEPT TEMPS BELOW MEX NUMBERS...ESPECIALLY IN THE NORTH. ...DLF... && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SHEETS/DLF ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 305 PM CST THU JAN 6 2005 .SYNOPSIS... DEPARTING WINTER STORM WELL OUT OF AREA OVER EASTERN GREAT LAKES WITH RIDGE OF HIGH PRESSURE AT SURFACE OVER SOUTHERN PLAINS POKING NORTH INTO CENTRAL IA EARLY THIS AFTERNOON. BACK EDGE OF UPPER COMA CLOUDS AND WEAK SURFACE CONVERGENCE ALONG LOW LEVEL TROUGH HAVE KEPT FLURRIES GOING INTO EARLY AFTERNOON OVER NW IL. UPSTREAM...AN UPPER LEVEL POSITIVE TILT TROUGH WAS MOVING THROUGH CENTRAL ROCKIES. FRESH SNOW COVER LIMITING AFTERNOON TEMPS TO TEENS AND LOWER 20S OVER CWA...WITH ONLY SINGLE DIGITS UPSTREAM IN CENTRAL AND NW IA. && .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)...MAIN CHALLENGE IS TEMPERATURES. RIDGE AXIS PROGGED TO SHIFT EAST OVER CWA THIS EVENING WITH STAGE SET FOR EARLY TEMPERATURE PLUNG BEFORE WEAK LOW LEVEL WARM AIR ADVECTION ENDS THE FALL OR ALLOWS SLIGHT RISE TOWARD MORNING. SOME CONCERN THAT LOW CLOUD FIELD THAT DEVELOPED UNDER RIDGE IN PARTIAL SNOW OR ICE COVERED AREAS OF KS AND MO MAY CONTINUE TO INCH NORTHWARD. HOWEVER...THESE CLOUDS FORMED IN AN AREA WITH LOW CONVECTIVE TEMPS THIS AFTERNOON AND WEAK ISENTROPIC IN RETURN FLOW ABOVE THE SURFACE HIGH. WITH VISIBLE IMAGERY SHOWING THESE CLOUDS TO BE RATHER THIN...WILL DISCOUNT THEM FOR FIRST HALF OF TONIGHT FOR ALL BUT FAR SOUTH. MOS GUIDANCE MINS FOR TONIGHT ARE CLOSE TO CURRENT OBS OVER MUCH OF CWA AND THUS DISCOUNTED. WENT CLOSER TO A BLEND OF META AND RUC SURFACE TEMPERATURES WITH RAPID PLUNGE AFTER SUNSET TO SUB ZERO READINGS IN DEEPEST SNOW COVERED EAST CENTRAL IA...WITH SINGLE DIGITS TO NEAR 12 IN SOUTHEAST. SOME MID AND HIGH CLOUDS...ALONG WITH LOW LEVEL RETURN FLOW...WILL THEN KEEP TEMPS STEADY OR POSSIBLY RISE A COUPLE DEGREES BY MORNING. ON FRIDAY...THE UPPER TROUGH PUSHES THROUGH BY EVENING WITH MAIN VORT CENTER PASSING ACROSS NORTHERN MO TO CENTRAL IL. WARM ADVECTION AND WEAK ISENTROPIC LIFT INCREASES AHEAD OF THIS FEATURE THROUGH DAY AND SHOULD RESULT IN MOSTLY CLOUDY SKIES. GFS MORE BULLISH WITH ISENTROPIC LIFT IN SE CWA AND THUS PRODUCES QPF BY EVENING WHILE OTHER SHORT RANGE MODELS KEEP CWA DRY. WILL GO WITH SLIGHT CHANCE POPS IN SE FOR LATE AFTERNOON AND EVENING FOR LIGHT SNOW WITH FLURRIES POSSIBLE ELSEWHERE. MOS GUIDANCE STILL TOO WARM FRIDAY AND UNDERCUT BY A COUPLE CATEGORIES NORTH AND A FEW DEGREES BELOW COLDEST MAV IN SOUTH WITH HIGHS RANGING FROM AROUND 20 NORTH TO LOWER 30S SOUTH WHERE ICE AND SNOW COVER THINNEST. EXPECT CLEARING TREND AS SHORTWAVE UPPER RIDGE MOVES OVERHEAD WITH TEMPS PLUNGING INTO SINGLE DIGITS AND TEENS...WELL BELOW COLDEST MAV GUIDANCE. ..SHEETS.. && .LONG TERM...(SATURDAY THROUGH MONDAY NIGHT)... MAIN CONCERN THROUGH THE WEEKEND WILL BE TEMPS WITH FLAT WSW UPPER FLOW AND SURFACE RIDGE DEPARTING REGION SATURDAY...SETTING UP WEAK RETURN FLOW SATURDAY NIGHT AND SUNDAY. MODELS DROP ANOTHER WEAK FRONT THROUGH THE REGION MONDAY. OF COURSE WITH SNOW COVER OVER MOST OF CWA WILL BE GOING NEAR OR UNDER COOLER MET NUMBERS SATURDAY/SATURDAY NIGHT. LIMITED MIXING ASSOCIATED WITH LIGHT WINDS NEAR THE SURFACE SATURDAY WILL ALSO LIMIT TEMP RECOVERY...IN ADDITION TO THE SNOW COVER. WEAK SLY FLOW SETS UP SUNDAY AHEAD OF SURFACE LOW MOVING ACROSS THE NCNTRL U.S. THE LOW DRAGS A WEAK COLD FRONT SOUTH THROUGH CWA EARLY MONDAY. THE GFS IS SHOWING SOME FORCING ASSOCIATED WITH FRONTOGENESIS AND S/W ENERGY MOVING ALONG THE BOUNDARY. AMOUNT OF MOISTURE MAY BE THE BIG ISSUE WITH ANY PCPN DEVELOPMENT. 12Z GFS RUN WAS SHOWING A NARROW SWATH OF 90 PCT H8 RH JUST N OF THE BOUNDARY BY 18Z...SO INTRODUCED LOW POPS FOR THE ENTIRE AREA. TEMP PROFILES 18Z MONDAY FAVOR RA IN THE SOUTH WHILE COLDER H8 TEMPS N SUGGEST A MIX IS POSSIBLE. (TUESDAY THROUGH THURSDAY)... LOOKS LIKE AN ACTIVE PERIOD THROUGH THE MIDDLE OF NEXT WEEK. GFS/ECMWF/UKMET IN REASONABLE AGREEMENT KEEPING SW FLOW OVER REGION WITH ZONAL FLOW OVER SRN CANADA HOLDING COLDER AIRMASS WELL TO THE NORTH. THE 06/00Z GFS LOOKS LIKE IT IS TRYING TO PHASE THE TWO STREAMS WEDNESDAY BRINING MORE ENERGY DOWN THE EAST SIDE OF THE ERN PAC RIDGE THAN THE EUROPEAN MODELS WHICH KEEP THE SPLIT FLOW INTACT THROUGH MID WEEK. THE 06/12Z GFS AT 108HR IS A LITTLE SLOWER WITH THIS PIECE OF ENERGY...SUPPORTING THE EUROPEAN MODELS SOLUTION. WILL TREND TOWARD THE ECMWF SOLUTION WITH STRONG BAROCLINIC ZONE...ENHANCED BY SNOWFIELD...SETTING UP OVER THE MID MISSISSIPPI VALLEY BY WEDNESDAY. WITH SW FLOW IN PLACE AND STRONG BAROCLINIC ZONE OVER CWA WILL CONTINUE CHANCE POPS ALREADY IN FCST FOR TUESDAY THROUGH THURSDAY. INITIALLY PCPN WILL BE RAIN IN THE SOUTH. NRN SECTIONS WILL LIKELY SEE A MIX OF PCPN TUESDAY NIGHT AND WEDNESDAY AS DEEP SNOW COVER ALTERS TO THE LOW LEVEL TEMP PROFILE. GRIDS CURRENTLY HAVE R/S...BUT AS WE DRAW CLOSER TO THE EVENT WOULD SUSPECT THAT THIS WILL TREND TOWARD FREEZING RN/DZ WITH ALL MODELS SHOWING WARM AIR AT H850. PCPN CWA WIDE TO CHANGE TO SNOW BY THURSDAY AS NRN AND SRN STREAMS PHASE...ALLOWING COLD CANADIAN AIR TO SURGE SOUTH OVER THE REGION. WITH SNOW IN PLACE...KEPT TEMPS BELOW MEX NUMBERS...ESPECIALLY IN THE NORTH. ...DLF... && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SHEETS/DLF ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 935 PM EST THU JAN 6 2005 .SHORT TERM... SRN FRINGE OF CWFA SAW WM FROPA BEFORE SUNSET...ALLOWING THESE CNTYS TO DRY OUT. ELSW...PLENTY OF LLVL MSTR REMAINS TRAPPED UNDER AN IMPRVS INVSN PER 00Z IAD SNDG. THIS PERMITTED OCCLUDED FRONT TO PASS THRU W/O SCOURING OUT LLVLS. WNDS JUST OFF THE DECK ARE FM THE W AT 10-15 KT. SINCE ETA/GFS HAD ENTIRE CWFA IN THE WARM SECTOR...THEIR SOLNS ARE SUSPECT ATTM...EVEN THE 18Z RUNS. RUC INIT BETTER IN THE LWR LVLS...AND ITS SOLN WL BE FAVORED. IN THIS LIGHT...AXIS OF SFC MSTR SHUD SHIFT EWD BTWN 06Z-09Z...AS PRES RISES MVS EWD. BEST MIXING WONT OCCUR TIL AFTR SUNRISE THO. SO...WL GO MORE PESSIMISTIC IN CLD FCST. PER REGIONAL RADAR...DONT SEE ANY ADDTL PCPN...AND WL RMV THIS ELEMENT FM GRIDS. OVNGT FCST REMPS APPR OK...THO WL BUMP MIN-T UP A CPL ACRS THE SW. && .AVIATION...A GREAT DEAL OF VARIABILITY ACRS TAF SITES THIS EVNG. LLVL MSTR TRAPPED BLO STEEP INVSN...AND DONT SEE THIS MVG AT SITES WHERE ITS IN PLACE. AS OCFNT MVS OFFSHR AND HIPRES MVS IN...A WNW WND WL DVLP...LIFTING LIFR FOG NEAR MIDNGT. HWVR...NOT SO OPTIMISTIC ON LIFR/VLIFR CIGS. ATTM THINK IT WL TAKE DAYTIME MIXING TO DISLODGE. HWVR...BWI IN PARTICULAR HAS HAD IT LIFT...PERHAPS DUE TO T-GRAD CAUSED BY THE BAY. WL CONT TO MONITOR. && .MARINE...WNDS LGT ATTM. P-GRAD NOT THAT STEEP...AND INVSN WUD KEEP WNDS ELEVATED ANYWAY. SO...WL BE DROPPING SCA FOR THE OVNGT. && .PREV DISCUSSION... SHORT TERM (TONIGHT AND FRIDAY)... WATER VAPOR LOOP SHOWS A MATURING UPPER LOW TRANSLATING NORTHEAST INTO THE CENTRAL GREAT LAKES WHILE A RIDGE DOMINATES THE EASTERN CONUS. A WAVE APPEARS TO BE DEVELOPING ACROSS THE CENTRAL ROCKIES...AT THE TAIL OF A SHEAR AXIS LOCATED APPROXIMATELY ALONG THE CANADIAN BORDER. ACARS 400-250MB WIND OBSERVATIONS REVEAL A SOUTHWESTERLY UPPER LEVEL JET FROM THE PLAINS NORTHEAST THROUGH THE EASTERN GREAT LAKES...WITH THE JET MAXIMUM OF 140-155KTS LOCATED ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY. 12Z SURFACE ANALYSIS SHOWS THE OCCLUDING 1003MB CYCLONE OVER NORTHWEST OHIO...WITH AN OCCLUDED BOUNDARY SOUTHEAST TO THE 1003MB TRIPLE POINT CYCLONE LOCATED OVER CENTRAL WEST VIRGINIA. THE WARM/STATIONARY BOUNDARY STRETCHES EAST FROM THE TRIPLE POINT ACROSS CENTRAL VIRGINIA...THEN NORTHEAST ACROSS THE DELMARVA. THE PRIMARY COLD FRONT STRETCHES DOWN THE WESTERN SLOPES OF THE APPALACHIANS...WITH A SECONDARY COLD FRONT ACROSS THE TENNESSEE VALLEY INTO THE SOUTHERN PLAINS. OCCLUDED/COLD FRONT NOW PRESSING EAST OF THE APPALACHIANS AND IS EXPECTED TO REACH THE CHESAPEAKE BAY THIS EVENING. LOW LEVEL WINDS WILL VEER AS A RESULT...ALLOWING DOWNSLOPE TO ERODE LOW LEVEL CLOUDS EAST OF THE MOUNTAINS. MEANWHILE...A FEW RAIN/SNOW SHOWERS WILL OCCUR IN THE CLIMATOLOGICALLY FAVORED UPSLOPE REGION OF THE MOUNTAINS THROUGH THE EVENING BEFORE MOISTURE DECREASES BELOW 3KFT AROUND MIDNIGHT. AS COLD ADVECTION CONTINUES OVERNIGHT...LAPSE RATES WILL STEEPEN ENOUGH ACROSS THE HIGHER ELEVATIONS TO SUPPORT WIND GUSTS OF ABOUT 35 MPH. WAVE DEVELOPING ACROSS THE CENTRAL ROCKIES AND APPROACH OF THE RIGHT ENTRANCE REGION OF THE NEXT UPPER LEVEL JET WILL TAKE ADVANTAGE OF DEEP SOUTHWESTERLY FLOW ALOFT TO ADVECT MOISTURE NORTHEAST INTO THE NORTHERN MID ATLANTIC REGION FRIDAY AFTERNOON. MAJORITY OF FORECAST AREA SHOULD ONLY SEE AN INCREASE IN HIGHER LEVEL CLOUDS...WHILE THERE MAY BE SOME LIGHT SHOWERS ACROSS WEST CENTRAL VIRGINIA BEFORE EVENING. DESPITE A DROP IN LOW LEVEL TEMPERATURES...DEEPER MIXING WILL YIELD WARMER TEMPERATURES THAN TODAY ACROSS THE NORTHERN FORECAST AREA. LONG TERM... MAIN CONCERN WILL BE PTYPE WITH THE FRIDAY NIGHT/SATURDAY SYSTEM. AT THIS TIME...FORECAST SOUNDINGS INDICATE PROFILES WILL BE WARM ENOUGH FOR AN ALL RAIN SYSTEM. SOUTHWEST OR NEARLY ZONAL FLOW SHOULD BE THE RULE IN THE MID LEVELS FOR THE EXTENDED PERIOD. FAST MOVING...WEAK AND HARD TO TIME IMPULSES ARE PROGGED TO TRAVERSE THE FLOW THROUGH THE PERIOD. AT THE SURFACE...HIGH PRESSURE CENTER HAS MOVED OFFSHORE BY 00Z SATURDAY AS AN INVERTED TROUGH DEVELOPS OVER THE SPINE OF THE APPALACHIANS. A SURFACE WAVE DEVELOPS OVER THE GULF STATES AND MOVES RAPIDLY NORTHWARD THROUGH SATURDAY. HIGH PRESSURE ONCE AGAIN BUILDS OVER THE REGION FOR THE LATTER HALF OF THE WEEKEND. BY EARLY MONDAY...SOUTHERLY FLOW HAS RETURNED TO THE REGION ON THE BACKSIDE OF THE HIGH CENTER. A FRONTAL BOUNDARY REMAINS STATIONARY JUST WEST OF THE CWFA THROUGH MIDWEEK...BEFORE SINKING SOUTHWARD ON DURING LATE THURSDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA....NONE. WV...NONE. MARINE...NONE && $$ UPDATE...HTS PREV DISCUSSION...ROGOWSKI/LISTEMAA md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 936 PM EST THU JAN 6 2005 .UPDATE... SOME SURFACE RIDGING NUDGED INTO SE MICHIGAN THIS EVENING AND ALLOWED SKIES TO CLEAR IN MANY LOCATIONS. MEANWHILE... SURFACE HIGH PRESSURE CURRENTLY OVER THE MID MISSISSIPPI VALLEY WILL SETTLE INTO THE OHIO VALLEY OVERNIGHT. THIS WILL GRADUALLY BRING BOUNDARY LAYER WINDS AROUND TO THE SOUTHWEST ACROSS THE SOUTHERN GREAT LAKES BY DAYBREAK. STRONG MID LEVEL SUBSIDENCE ALREADY WORKING INTO LOWER MICHIGAN WILL ACT TO STRENGTHEN THE LOW LEVEL INVERSION... WHICH WILL CONTINUE TO ALLOW THE STRATUS ACROSS IL/IN/WESTERN LOWER MI TO EXPAND INTO SE MICHIGAN. THE 00Z KILX SOUNDING WAS A BIT COLDER IN THE BOUNDARY LAYER THAN SUGGESTED BY MODEL SOLUTIONS. SUSPECT THIS COLDER AIRMASS WILL HELP KEEP INVERSION HEIGHTS UP A BIT HIGHER OVER LAKE MICHIGAN THAN DEPICTED BY EITHER RUC OR ETA MODEL SOUNDINGS. INSTABILITY SHOULD BE ENOUGH TO PROVIDE A FEW FLURRIES OFF THE LAKE. THE LATEST GRR RADAR SUPPORTS THIS. SO WILL EXTEND SCATTERED FLURRIES INTO THE OVERNIGHT. WITH THE BRIEF CLEARING EXPERIENCED THIS EVENING... TEMPERATURES ACROSS MOST OF SE MICHIGAN FELL TO THE CURRENT FORECASTED LOWS. THE TEMPS SHOULD LEVEL OFF SINCE CLOUDS ARE ALREADY MOVING BACK INTO THE REGION. SO WILL JUST LOWER OVERNIGHT MIN TEMPS A COUPLE DEGREES. && .SHORT TERM...THROUGH FRIDAY (ISSUED AT 405 PM) SURFACE LOW RESPONSIBLE FOR THE WINTER STORM THIS MORNING IS NOW WELL OFF TO OUR EAST AT 29.60 INCHES OVER LAKE SUPERIOR. THIS LOW WILL CONTINUE TO PULL OFF TO OUR EAST THIS EVENING. A SURFACE TROUGH CURRENTLY EXTENDS FROM THIS LOW BACK ACROSS CENTRAL LOWER MICHIGAN. AN AREA OF CONVERGENCE AROUND THIS TROUGH HAS BEEN RESPONSIBLE FOR SNOW SHOWERS THROUGH THE AFTERNOON HOURS...THIS ACTIVITY HAS BEEN CONFINED MOSTLY TO THE GENESEE AND SAGINAW VALLEY THIS AFTERNOON BUT HAS NOW SPREAD SOUTHWARD DOWN TO M59. A FEW FLURRIES ARE POSSIBLE FOR A COUPLE OF HOURS THIS EVENING SOUTH OF M59. THE TROUGH ACROSS THE SAGINAW VALLEY WILL GET WASHED OUT EARLY THIS EVENING AS THE LOW PULLS OFF TO THE EAST AND ANTICYLONIC FLOW FROM HIGH PRESSURE APPROACHING FROM OUR SOUTHWEST BEGINS TO TAKE OVER. AS THIS HAPPENS...PRECIPITATION WILL COME TO AN END AS A BROAD SURFACE RIDGE WORKS IN ACROSS THE FORECAST AREA OVERNIGHT. WINDS WILL BACK TO THE SOUTHWEST BY MORNING BRINGING IN DRIER AIR. BIGGEST CHALLENGE WAS CLOUD COVER AND ITS IMPACT ON MAX AND MIN TEMPS. ETA IS MUCH MORE PESSIMISTIC WITH CLOUD COVER THROUGH FRIDAY...SUGGESTING LOW CLOUDS TO REMAINED TRAPPED UNDER INVERSION. GFS...ON THE OTHER HAND...BEGINS TO SCATTER CLOUDS OUT TOWARD FRIDAY MORNING. THE THINKING IS CLOUDS WILL HANG AROUND FOR THE MOST PART BUT THERE SHOULD BE ENOUGH HOLES THROUGH THE DAY ON FRIDAY TO GO WITH PARTLY SUNNY...UNTIL THEN WE WILL STAY CLOUDY OVERNIGHT. GUIDANCE NUMBERS LOOK REASONABLE BASED ON THESE ANTICIPATIONS...WENT CLOSER TO THE MAV GUIDANCE. && .LONG TERM... THE PATTERN APPEARS TO BE RELATIVELY QUIET THROUGH THE WEEKEND...AT LEAST COMPARED TO THE LAST FEW DAYS AND THE COMING WEEK. THERE IS A CAVIOT TO THIS UNFORTUNATELY. ETA...AND TO A DEGREE GFS HAS BECOME A BIT MORE AMPLIFIED WITH THE UPPER DISTURBANCE THAT RACES OUT OF THE MIDDLE OF THE CONUS FRIDAY INTO SATURDAY. THIS SYSTEM RESULTS FROM THE PHASING OF THE UPPER LOW OVER THE DAKOTAS WITH A VORTICITY CENTER CURRENTLY ROTATING THROUGH NEVADA. A BULK OF THE PRECIPITATION WITH THIS SYSTEM IS STILL FORECAST TO REMAIN WELL SOUTH OF THE CWA AS THE FLOW REMAINS BASICALLY ZONAL AND KEEPS THIS SYSTEM PROGRESSIVE. THAT SAID...12Z ETA OUTPUTS BETTER THAN A 1/4 INCH OF QPF LATE FRIDAY NIGHT INTO SATURDAY MORNING ACROSS THE SOUTHERN CWA. DON/T REALLY BUY THIS AMOUNT...BUT GFS ALSO PUTS SOME LIGHT SNOW INTO AREA DURING THIS TIMEFRAME (SUPPORTED BY CMC AND WRF AS WELL). WILL ADD A CHANCE OF LIGHT SNOW ACROSS SOUTHERN CWA DUE TO THIS CONSISTENCY IN MODELS NEXT WEEK WILL BE A DIFFICULT CHORE IN THE COMING DAYS. THE UPPER PATTERN TRENDS FROM THE BASICALLY ZONAL FLOW ON THE BASE OF LARGE NORTH AMERICAN TROF...TO SHARP SOUTHWEST FLOW IN ADVANCE OF STRONGLY AMPLIFYING WESTERN CONUS TROF DURING THE MIDDLE OF NEXT WEEK. AFTER THE SATURDAY WAVE RIPPLES THROUGH...ANOTHER RACES THROUGH LATE SUNDAY INTO MONDAY...BRINGING ANOTHER CHANCE OF -RA/-SN. THE ASSOCIATED FRONT THEN DROPS SOUTH OF THE AREA MONDAY NIGHT...ONLY TO RETURN ON NORTH IN INCREASINGLY SOUTHWEST UPPER FLOW TUESDAY INTO WEDNESDAY. WILL READJUST THE PLACEMENT/TIMING OF PRECIPITATION SOMEWHAT DURING THIS TIMEFRAME...BUT OVERALL FEEL TO THE FORECAST REMAINS THE SAME WITH PERIODIC CHANCE -RA/-SN SUNDAY NIGHT INTO TUESDAY. THEREAFTER...WE ENTER A PERIOD WITH A BETTER CHANCE OF SIGNIFICANT PRECIPITATION AS SUBTROPICAL/GULF MOISTURE SURGE NORTH/NORTHEAST ON THE LEADING EDGE OF DIGGING WESTERN TROF. GFS OUTPUTS QUITE A LOT OF RAIN FROM LATE TUESDAY THROUGH WEDNESDAY...AND WILL PIN THIS TIME AS THE BEST CHANCE OF RAIN...AS OPPOSED TO LIGHT SHOWERS ETC. BY THE END OF THIS FORECAST PERIOD...ARCTIC AIR RETURNS TO THE LAKES REGION. THIS TRANSITION IS FORECAST TO OCCUR IN ONE FASHION OR ANOTHER BY A HOST OF MODELS. THE GENERAL SCENARIO BEING A STRONG ARCTIC STORM CROSSING FROM SIBERIA OVER ALASKA. THIS SYSTEM KICKS AN UPPER LOW THAT IS IN THE PROCESS OF CUTTING OFF NEAR THE PACIFIC NORTHWEST ATTM ON INTO THE CENTRAL CONUS...WITH THE ARCTIC SYSTEM/AIRMASS THEN CHASING RAPIDLY IN BEHIND IT. GFS FOCUSES MUCH MORE ON THE NORTHERN SYSTEM & BASICALLY BRINGS THE ARCTIC FRONT THROUGH "UNEVENTFUL"...ASIDE FROM THE STEADY STREAM OF MOISTURE/RAIN BEFOREHAND. 12Z CMC AND 00Z ECMWF KEEP THE PACIFIC NORTHWEST SHORTWAVE INTACT AND RIDE IT INTO THE AREA ALONG THE ARCTIC FRONT...LEADING TO A BETTER CHANCE OF A SIGNIFICANT STORM TOWARD THE END OF THE FCST. NO CONFIDENCE IN EITHER SPECIFIC SOLUTION AT THIS STAGE IN THE GAME...BUT GIVEN THE STRONG OVERALL CONSENSUS ON THE UPPER PATTERN TRANSITION BY MODELS...AT LEAST FOR A DAY 6/7 FORECAST WILL TREND FORECAST MUCH COLDER AT THE TAIL END OF THE FORECAST...AND TRANSITION RAIN CHANCE TO LIGHT SNOW SHOWERS CHCS. && .AVIATION...ISSUED AT 623 PM. SURFACE HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY TONIGHT. THIS WILL ALLOW THE BOUNDARY LAYER WINDS TO BACK MORE SOUTHWESTERLY OVERNIGHT. ETA AND RUC MODEL SOUNDINGS SHOW INVERSION HEIGHTS DROPPING FROM 5K FEET AT 00Z TO 3K FEET BY 12Z. THERE IS ENOUGH INSTABILITY OFF LAKE MICHIGAN TO MAINTAIN LAKE STRATO CU AND SCATTERED FLURRIES THROUGH THE NIGHT. BASED ON INVERSION HEIGHTS AND CIGS UPSTREAM... WILL KEEP CEILINGS BETWEEN 2K AND 3K FEET THROUGH THE NIGHT. THERE ARE QUITE A FEW BREAKS IN THE MVFR CIGS AT THIS TIME. EXPECT AS THE INVERSION LOWERS AND STRENGTHENS TONIGHT... THESE BREAKS WILL FILL BACK IN... ESPECIALLY GIVEN ALL THE LOW MOISTURE STILL IN PLACE ACROSS ILLINOIS AND INDIANA. THE LOW LEVEL FLOW BECOMES MORE SOUTHERLY BY FRIDAY MORNING. THIS ALONG WITH SOME LOW LEVEL DRY AIR ADVECTION SHOULD SCATTER THE LOW CLOUDS OUT DURING THE MORNING. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ GURNEY/SHULER/CONSIDINE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 623 PM EST THU JAN 6 2005 .AVIATION... SURFACE HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY TONIGHT. THIS WILL ALLOW THE BOUNDARY LAYER WINDS TO BACK MORE SOUTHWESTERLY OVERNIGHT. ETA AND RUC MODEL SOUNDINGS SHOW INVERSION HEIGHTS DROPPING FROM 5K FEET AT 00Z TO 3K FEET BY 12Z. THERE IS ENOUGH INSTABILITY OFF LAKE MICHIGAN TO MAINTAIN LAKE STRATO CU AND SCATTERED FLURRIES THROUGH THE NIGHT. BASED ON INVERSION HEIGHTS AND CIGS UPSTREAM... WILL KEEP CEILINGS BETWEEN 2K AND 3K FEET THROUGH THE NIGHT. THERE ARE QUITE A FEW BREAKS IN THE MVFR CIGS AT THIS TIME. EXPECT AS THE INVERSION LOWERS AND STRENGTHENS TONIGHT... THESE BREAKS WILL FILL BACK IN... ESPECIALLY GIVEN ALL THE LOW MOISTURE STILL IN PLACE ACROSS ILLINOIS AND INDIANA. THE LOW LEVEL FLOW BECOMES MORE SOUTHERLY BY FRIDAY MORNING. THIS ALONG WITH SOME LOW LEVEL DRY AIR ADVECTION SHOULD SCATTER THE LOW CLOUDS OUT DURING THE MORNING. && .SHORT TERM...THROUGH FRIDAY (ISSUED AT 405 PM) SURFACE LOW RESPONSIBLE FOR THE WINTER STORM THIS MORNING IS NOW WELL OFF TO OUR EAST AT 29.60 INCHES OVER LAKE SUPERIOR. THIS LOW WILL CONTINUE TO PULL OFF TO OUR EAST THIS EVENING. A SURFACE TROUGH CURRENTLY EXTENDS FROM THIS LOW BACK ACROSS CENTRAL LOWER MICHIGAN. AN AREA OF CONVERGENCE AROUND THIS TROUGH HAS BEEN RESPONSIBLE FOR SNOW SHOWERS THROUGH THE AFTERNOON HOURS...THIS ACTIVITY HAS BEEN CONFINED MOSTLY TO THE GENESEE AND SAGINAW VALLEY THIS AFTERNOON BUT HAS NOW SPREAD SOUTHWARD DOWN TO M59. A FEW FLURRIES ARE POSSIBLE FOR A COUPLE OF HOURS THIS EVENING SOUTH OF M59. THE TROUGH ACROSS THE SAGINAW VALLEY WILL GET WASHED OUT EARLY THIS EVENING AS THE LOW PULLS OFF TO THE EAST AND ANTICYLONIC FLOW FROM HIGH PRESSURE APPROACHING FROM OUR SOUTHWEST BEGINS TO TAKE OVER. AS THIS HAPPENS...PRECIPITATION WILL COME TO AN END AS A BROAD SURFACE RIDGE WORKS IN ACROSS THE FORECAST AREA OVERNIGHT. WINDS WILL BACK TO THE SOUTHWEST BY MORNING BRINGING IN DRIER AIR. BIGGEST CHALLENGE WAS CLOUD COVER AND ITS IMPACT ON MAX AND MIN TEMPS. ETA IS MUCH MORE PESSIMISTIC WITH CLOUD COVER THROUGH FRIDAY...SUGGESTING LOW CLOUDS TO REMAINED TRAPPED UNDER INVERSION. GFS...ON THE OTHER HAND...BEGINS TO SCATTER CLOUDS OUT TOWARD FRIDAY MORNING. THE THINKING IS CLOUDS WILL HANG AROUND FOR THE MOST PART BUT THERE SHOULD BE ENOUGH HOLES THROUGH THE DAY ON FRIDAY TO GO WITH PARTLY SUNNY...UNTIL THEN WE WILL STAY CLOUDY OVERNIGHT. GUIDANCE NUMBERS LOOK REASONABLE BASED ON THESE ANTICIPATIONS...WENT CLOSER TO THE MAV GUIDANCE. && .LONG TERM... THE PATTERN APPEARS TO BE RELATIVELY QUIET THROUGH THE WEEKEND...AT LEAST COMPARED TO THE LAST FEW DAYS AND THE COMING WEEK. THERE IS A CAVIOT TO THIS UNFORTUNATELY. ETA...AND TO A DEGREE GFS HAS BECOME A BIT MORE AMPLIFIED WITH THE UPPER DISTURBANCE THAT RACES OUT OF THE MIDDLE OF THE CONUS FRIDAY INTO SATURDAY. THIS SYSTEM RESULTS FROM THE PHASING OF THE UPPER LOW OVER THE DAKOTAS WITH A VORTICITY CENTER CURRENTLY ROTATING THROUGH NEVADA. A BULK OF THE PRECIPITATION WITH THIS SYSTEM IS STILL FORECAST TO REMAIN WELL SOUTH OF THE CWA AS THE FLOW REMAINS BASICALLY ZONAL AND KEEPS THIS SYSTEM PROGRESSIVE. THAT SAID...12Z ETA OUTPUTS BETTER THAN A 1/4 INCH OF QPF LATE FRIDAY NIGHT INTO SATURDAY MORNING ACROSS THE SOUTHERN CWA. DON/T REALLY BUY THIS AMOUNT...BUT GFS ALSO PUTS SOME LIGHT SNOW INTO AREA DURING THIS TIMEFRAME (SUPPORTED BY CMC AND WRF AS WELL). WILL ADD A CHANCE OF LIGHT SNOW ACROSS SOUTHERN CWA DUE TO THIS CONSISTENCY IN MODELS NEXT WEEK WILL BE A DIFFICULT CHORE IN THE COMING DAYS. THE UPPER PATTERN TRENDS FROM THE BASICALLY ZONAL FLOW ON THE BASE OF LARGE NORTH AMERICAN TROF...TO SHARP SOUTHWEST FLOW IN ADVANCE OF STRONGLY AMPLIFYING WESTERN CONUS TROF DURING THE MIDDLE OF NEXT WEEK. AFTER THE SATURDAY WAVE RIPPLES THROUGH...ANOTHER RACES THROUGH LATE SUNDAY INTO MONDAY...BRINGING ANOTHER CHANCE OF -RA/-SN. THE ASSOCIATED FRONT THEN DROPS SOUTH OF THE AREA MONDAY NIGHT...ONLY TO RETURN ON NORTH IN INCREASINGLY SOUTHWEST UPPER FLOW TUESDAY INTO WEDNESDAY. WILL READJUST THE PLACEMENT/TIMING OF PRECIPITATION SOMEWHAT DURING THIS TIMEFRAME...BUT OVERALL FEEL TO THE FORECAST REMAINS THE SAME WITH PERIODIC CHANCE -RA/-SN SUNDAY NIGHT INTO TUESDAY. THEREAFTER...WE ENTER A PERIOD WITH A BETTER CHANCE OF SIGNIFICANT PRECIPITATION AS SUBTROPICAL/GULF MOISTURE SURGE NORTH/NORTHEAST ON THE LEADING EDGE OF DIGGING WESTERN TROF. GFS OUTPUTS QUITE A LOT OF RAIN FROM LATE TUESDAY THROUGH WEDNESDAY...AND WILL PIN THIS TIME AS THE BEST CHANCE OF RAIN...AS OPPOSED TO LIGHT SHOWERS ETC. BY THE END OF THIS FORECAST PERIOD...ARCTIC AIR RETURNS TO THE LAKES REGION. THIS TRANSITION IS FORECAST TO OCCUR IN ONE FASHION OR ANOTHER BY A HOST OF MODELS. THE GENERAL SCENARIO BEING A STRONG ARCTIC STORM CROSSING FROM SIBERIA OVER ALASKA. THIS SYSTEM KICKS AN UPPER LOW THAT IS IN THE PROCESS OF CUTTING OFF NEAR THE PACIFIC NORTHWEST ATTM ON INTO THE CENTRAL CONUS...WITH THE ARCTIC SYSTEM/AIRMASS THEN CHASING RAPIDLY IN BEHIND IT. GFS FOCUSES MUCH MORE ON THE NORTHERN SYSTEM & BASICALLY BRINGS THE ARCTIC FRONT THROUGH "UNEVENTFUL"...ASIDE FROM THE STEADY STREAM OF MOISTURE/RAIN BEFOREHAND. 12Z CMC AND 00Z ECMWF KEEP THE PACIFIC NORTHWEST SHORTWAVE INTACT AND RIDE IT INTO THE AREA ALONG THE ARCTIC FRONT...LEADING TO A BETTER CHANCE OF A SIGNIFICANT STORM TOWARD THE END OF THE FCST. NO CONFIDENCE IN EITHER SPECIFIC SOLUTION AT THIS STAGE IN THE GAME...BUT GIVEN THE STRONG OVERALL CONSENSUS ON THE UPPER PATTERN TRANSITION BY MODELS...AT LEAST FOR A DAY 6/7 FORECAST WILL TREND FORECAST MUCH COLDER AT THE TAIL END OF THE FORECAST...AND TRANSITION RAIN CHANCE TO LIGHT SNOW SHOWERS CHCS. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ GURNEY/SHULER/CONSIDINE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 401 PM EST THU JAN 6 2005 .DISCUSSION... MAIN FORECAST CONCERNS ARE SKY COVER AND PRECIPITATION THROUGH SUNDAY. CURRENT WEATHER...19Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AND UPPER LOW OVER LOWER MICHIGAN...A SHRTWV TROUGH EXTENDING FROM SE MONTANA INTO NEVADA...AND A MUCH STRONGER SHRTWV TROUGH DIGGING DOWN THROUGH BRITISH COLUMBIA. A DEFORMATION BAND IS NOTED ON BOTH SATELLITE AND RADAR IMAGERY...CURRENTLY LOCATED OVER THE SOUTHEASTERN U.P. INTO NORTHERN LOWER MICHIGAN. SKIES CLEAR OUT TO THE WEST OF THIS BAND...WHERE A SURFACE HIGH PRESSURE AREA REMAINS IN CONTROL. TEMPERATURES UNDER THE HIGH WERE QUITE COLD THIS MORNING...WITH READINGS OF 35 TO 40 BELOW ZERO OVER NORTHERN MN. CONDITIONS ARE ALSO QUITE DRY UNDER THIS HIGH AS SEEN ON THE 12Z INL SOUNDING (P.W. AROUND 0.03 IN AND DEWPOINT DEPRESSIONS OF 20 TO 30C BETWEEN 600 AND 950MB). THE COMBINATION OF THE DRIER AIR MOVING IN AND WINDS BACKING AROUND TO THE SW HAS HELPED TO SHUT OFF THE LAKE EFFECT OVER THE U.P.. OFF TO THE NW...A LOW PRESSURE AREA IS LOCATED OVER NE MANITOBA WITH A COLD FRONT EXTENDING SW INTO CENTRAL SASKATCHEWAN. PRECIPITABLE WATER INCREASES TO 0.25 IN AHEAD OF THIS FRONT PER THE 12Z SOUNDING AT CYQD (THE PAS ON THE NW END OF LAKE WINNIPEG)...BUT DEWPOINT DEPRESSIONS ARE STILL ON THE ORDER OF 30C BETWEEN 750 AND 850MB. THIS LOW LEVEL DRY AIR HAS RESTRICTED CLOUD FORMATION TO ABOVE 10000 FT PER OBSERVATIONS. THE MORE SIGNIFICANT FACTOR ASSOCIATED WITH THE FRONT ARE THE WINDS WITH CWPL AND CYQD SHOWING WESTERLY 850MB WINDS AT 40-50 KT. MODELS...AGREEMENT IS PRETTY GOOD THROUGH SATURDAY SO FOLLOWED THE ETA FOR DETAILS. AFTER SATURDAY...THERE ARE SOME DISCREPANCIES WITH THE PATTERN BETWEEN THE GFS...ETA AND UKMET...WHICH ARE NOTED IN THAT SECTION. TONIGHT...THE HIGH PRESSURE RIDGE OVER MN IS PROGGED TO CROSS UPPER MICHIGAN AND REFOCUS INTO A CENTER OVER THE OHIO VALLEY AS THE COLD FRONT TO THE NW MOVES TO NW ONTARIO BY 12Z. WITH THE PRESSURE GRADIENT INCREASING...THEREFORE INCREASING THE WINDS...TEMPERATURES WILL NOT DROP NEARLY AS MUCH AS THEY DID THIS MORNING IN NORTHERN MN. WINDS TURNING TO THE SW AND 925MB TEMPS AROUND -9C MAY SUPPORT THE DEVELOPMENT OF SOME LAKE EFFECT SNOW OFF OF LAKE MICHIGAN INTO SCHOOLCRAFT COUNTY OVERNIGHT...THOUGH WITH THE INVERSIONS BETWEEN 925MB AND 900MB IT WILL NOT BE ANYTHING MAJOR...MAYBE ONLY A FEW FLURRIES OR A LIGHT SNOW SHOWER. OTHERWISE...THE AFOREMENTIONED DRY AIR AND THE EXIT OF THE DEFORMATION BAND WILL ALLOW SKIES TO COMPLETELY CLEAR OUT ACROSS THE CWA. FRIDAY...SHRTWV TROUGH OVER NEVADA MOVES TO THE CENTRAL PLAINS BY 18Z AND INTO MISSOURI BY 00Z...MEANWHILE THE SURFACE COLD FRONT TO OUR NW MOVES TO WESTERN LAKE SUPERIOR BY 00Z. WITH THE FRONT ORIENTING ITSELF WITH THE UPPER LEVEL FLOW...THE FRONT WILL WEAKEN AND MOVE SLOWLY...WHICH IS WHAT THE MODELS SHOW. 00Z ETA SHOWED A STRONGER FRONT...BUT BOTH THE 06Z AND 12Z RUNS HAVE NOW TRENDED AWAY FROM IT. MOISTURE CONTINUES TO LOOK LIMITED WITH THE FRONT DUE TO BOTH LINGERING DRY AIR AND THE SHRTWV TROUGH MOVING THROUGH THE CENTRAL PLAINS. SO OTHER THAN FOR SOME LIGHT LAKE EFFECT SNOW SHOWERS EAST OF MANISTIQUE IN THE MORNING...SHOULD BE A MOSTLY SUNNY DAY. ETA AND GFS SOUNDINGS DO SHOW SOME HIGHER RH IN THE LOWEST 2000 FT DURING THE AFTERNOON...BUT DO NOT REALLY SEE WHERE ITS COMING FROM. INITIAL THOUGHT IS SNOWMELT ACROSS THE PLAINS TODAY WHICH IS TRANSPORTED THROUGH MN INTO WI AND UPPER MICHIGAN ON FRIDAY. THE 280K ISENTROPIC LIFT PLOT FROM THE ETA SORT OF SUGGESTS THIS. BUT WITHOUT ANY LOW CLOUD OUT THERE AT THE MOMENT...HARD TO BELIEVE THIS WILL OCCUR. LOOKED AT SURFACE DEWPOINT COMPARISONS BETWEEN OBSERVED AND MODELS AT 18Z AND I SEE THAT THEY ARE ABOUT 3-5C HIGHER ON THE MODELS THAN OBSERVED. GIVEN THIS...WILL STAY MORE WITH A PARTLY CLOUDY FORECAST. FRIDAY NIGHT...COLD FRONT SLIDES INTO UPPER MICHIGAN BUT STOPS AS UPPER LEVEL RIDGING FORMS IN ADVANCE OF A DEVELOPING UPPER LEVEL LOW IN THE PACIFIC NW. COLD ADVECTION WITH THE FRONT IS MINIMAL WITH 850MB TEMPS FALLING FROM -5C AT 21Z TO -10C AT 12Z OVER WESTERN SUPERIOR. THIS IS JUST COLD ENOUGH FOR SOME LAKE EFFECT SNOW SHOWERS...BUT WITH PLENTY OF WIND SHEAR BEHIND THE FRONT BETWEEN THE SURFACE AND 850MB...DO NOT EXPECT TO SEE MUCH IN THE WAY OF ORGANIZED LAKE EFFECT. SATURDAY...COLD FRONT BECOMING STATIONARY OVER UPPER MICHIGAN OR MOVES SLIGHTLY BACK NORTHWARD AS UPPER LEVEL RIDGING CONTINUE TO BUILD OVER THE GREAT LAKES. TO THE WEST...A SHRTWV EJECTING OUT OF THE UPPER LOW ALONG THE PACIFIC NW COAST MOVES INTO MONTANA BY 00Z IN THE SW FLOW ALOFT. A SURFACE LOW DEVELOPS OVER SW NORTH DAKOTA AS A RESULT OF THIS SHRTWV...WITH THE WARM FRONT CONNECTED TO THE OLD COLD FRONT OVER UPPER MICHIGAN. LACK OF ANY MOISTURE IN THE LOW TO MID LEVELS ALONG WITH NO UPPER SUPPORT WILL KEEP PRECIPITATION CHANCES SLIM. THE ONLY PLACE FOR PRECIPITATION WILL BE FOR THE LAKE EFFECT AREAS IN THE MORNING UNTIL THE FRONT LIFTS BACK NORTHWARD. SATURDAY NIGHT INTO SUNDAY...SHRTWV OVER MONTANA AND THE ASSOCIATED SURFACE LOW MOVE NORTHEAST INTO NORTHERN ONTARIO BY 12Z SUN...PULLING THE WARM FRONT NORTHWARD. LITTLE PRECIPITATION EXPECTED AGAIN DUE TO LACK OF UPPER SUPPORT AND MOISTURE. MORE MOISTURE MOVES IN ON SUN WITH ANOTHER SHRTWV EJECTING OUT OF THE PACIFIC NW TROUGH. THIS SHRTWV HELPS DEVELOP A SURFACE LOW OVER SOUTH CENTRAL SOUTH DAKOTA AT 12Z SUN WHICH MOVES TO NW WI BY 00Z. THIS POSITION IS A COMPROMISE BETWEEN THE GFS WHICH IS FARTHER NORTH AND UKMET FARTHER SOUTH. HAVE KEPT IN A SLIGHT CHANCE OF SNOW (MIXED WITH RAIN EAST WHERE TEMPERATURES ARE WARMER)...HOWEVER NOT REAL EXCITED WITH PRECIPITATION EXCEPT ON THE NW SIDE OF THE LOW. TEMPERATURES HAVE BEEN RAISED TOO FOR BOTH SAT NIGHT AND SUN...THOUGH NOT GOING HAS HIGH AS THE MAV GUIDANCE GIVEN THAT THE ETA AND UKMET ARE COLDER. EXTENDED (MON THROUGH THU)...MODELS AGREE ON THE GENERAL PATTERN THROUGHOUT THE PERIOD...HOWEVER THERE IS SOME UNCERTAINTY TOWARDS THU WITH REGARDS TO HOW FAST THE COLD AIR OVER WESTERN CANADA PUSHES E. ON MON...A SHRTWV MOVING DOWN THE BRITISH COLUMBIA COAST HELPS TO BOTH SHEAR AND KICK OUT THE SHRTWV ALONG THE PACIFIC NORTHWEST COAST. AS THE BRITISH COLUMBIA SHRTWV DIGS SOUTHWARD...THE OTHER SHRTWV PUSHES INTO THE FOUR CORNERS AREA...RESULTING IN THE DEVELOPMENT OF A SURFACE LOW OVER KANSAS ON TUE. THE WARM FRONT ASSOCIATED WITH THIS LOW EXTENDS NORTHEASTWARD INTO NORTHERN ILLINOIS. BY TUE NIGHT...A POLAR VORTEX SETS UP OVER PARTS OF NORTHERN ALBERTA AND SASKATCHEWAN WITH AN UPPER LEVEL TROUGH EXTENDING SOUTHWARD INTO MONTANA. TEMPERATURES VERY COLD UNDER THIS VORTEX WITH 850MB READINGS AROUND -40C. THE UPPER LEVEL TROUGH HELPS TO PULL THE KANSAS SURFACE LOW NE TO THE GREAT LAKES AREA BY WEDNESDAY MORNING...THEN OFF TO WESTERN QUEBEC WEDNESDAY NIGHT. HOW QUICK THIS OCCURS DEPENDS ON HOW FAST THE POLAR VORTEX AND ASSOCIATED UPPER LEVEL TROUGH MOVE EASTWARD. HALF OF THE GFS ENSEMBLES SUPPORT A SLOWER SOLUTION AND THE OTHER HALF ONE LIKE THE 00Z GFS. THE 06Z/12Z GFS AND 00Z/12Z UKMET SEEM TO BE A GOOD COMPROMISE...THOUGH THE SLOWER SOLUTION MAY END UP PANNING OUT GIVEN HOW STRONG THE RIDGING IS OVER THE EAST PACIFIC. FOR THU...EXPECT COLD AIR TO MOVE IN BEHIND THE LOW PRESSURE SYSTEM MOVING THROUGH THE LAKES...INITIATING LAKE EFFECT SNOWS OFF OF SUPERIOR. AS FOR THE GRIDS...NO MAJOR CHANGES WERE MADE EXCEPT PUTTING IN A CHANCE OF RAIN AND SNOW FOR WEDNESDAY IN THE EAST HALF OF THE U.P. HAS WARMER AIR FLOWS NORTH AHEAD OF THE LOW PRESSURE SYSTEM. IF EVERYTHING STAYS ON TRACK WITH THE LATEST 12Z GFS/ECMWF/UKMET...THERE WILL NEED TO BE A PERIOD OF FREEZING RAIN PUT IN TOO...BUT THE EVENT IS TOO FAR OUT TO DETERMINE THAT AT THE MOMENT. EITHER WAY...TUESDAY NIGHT INTO WEDNESDAY SYSTEM LOOKS INTERESTING FOR THE ENTIRE EAST HALF OF THE COUNTRY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 349 AM CST THU JAN 6 2005 .DISCUSSION... FINALLY SEEING THE WINTER STORM PULLING OUT OF THE REGION. SURFACE OBS SHOWING LINGERING FLURRIES AND POSSIBLY A LITTLE FREEZING DRIZZLE OVERNIGHT. WILL CONTINUE TO SEE THAT ACROSS MUCH OF THE FORECAST AREA EARLY THIS MORNING...WITH NO ACCUMULATION EXPECTED. TEMPS THROUGH THE NEXT SEVERAL DAYS ARE THE PRIMARY CONCERN AT THE MOMENT. CLOUDS WILL BE ON THE DECREASE TODAY...ALTHOUGH TEMPS THIS AFTERNOON WILL REMAIN COOL. THE COOL TEMPS AND CLEARING SKIES WILL SET THE REGION UP FOR ANOTHER COLD NIGHT TONIGHT. ALTHOUGH TEMPS FOR MOST LOCATIONS WILL NOT BE AS COLD AS THIS MORNING...WITH WARM AIR ADVECTION SETTING UP. DESPITE THE WARM AIR ADVECTION...TEMPS WILL STILL MODERATE SOME ON FRIDAY WITH THE LAYER OF ICE AND SNOW ON EVERYTHING. GFS/ETA MODELS INDICATE A WEAK COLD FRONT WILL TRY TO MOVE ACROSS THE REGION LATE FRIDAY AND FRIDAY NIGHT SO HAVE KEPT LOWS ON THE COOL SIDE. WARM AIR ADVECTION STARTS UP IN EARNEST ONCE AGAIN OVER THE WEEKEND. SO EXPECT TEMPS TO FOLLOW SUIT. WILL HAVE TO WATCH FOR FOG SATURDAY NIGHT. SOUNDINGS (ESPECIALLY THE ETA) SHOW A STRONG FOG PROFILE. BOTH GFS AND ETA SHOW HIGHER DEW POINTS RAPIDLY MOVING NORTH INTO THE REGION...AS TROUGH OUT WEST DEVELOPS AND PUSHES CLOSER. NRR && .PREV DISCUSSION... 858 PM WED... HAVE REVAMPED WARNINGS A BIT. EXTENDED THE ONE FOR NORTHWEST MISSOURI UNTIL MIDNIGHT AND HAVE INCLUDED EXTREME NORTHEAST KANSAS. DEFORMATION BAND ROTATING THROUGH NORTHEAST KANSAS WILL CONTINUE TO PRODUCE ANOTHER COUPLE OF INCHES ACROSS THAT REGION THIS EVENING. SCALED BACK THE WARNING IN NORTH CENTRAL MISSOURI. THINK THIS DEFORMATION BAND WILL GRADUALLY LIFT NORTHEAST...SO ONLY COUNTIES ALONG THE IOWA BORDER SHOULD SEE ANY MORE SIGNIFICANT SNOWFALL ACCUMULATION. WILL BRING TEMPERATURES UP JUST A TOUCH AROUND THE KANSAS CITY AREA FOR TONIGHT...AS CLOUD COVER SHOULD KEEP READINGS JUST A LITTLE HIGHER THAN PREVIOUSLY THOUGHT. STILL LOOKS QUITE COLD IN NORTHWEST MISSOURI...WHERE SINGLE DIGITS ARE POISED JUST TO THE NORTHWEST...AND SHOULD MOVE IN AS SNOW LETS UP...AND DEWPOINTS START TO TUMBLE. PC 704 PM WED... NOT SEEING SECONDARY TROWAL PREVIOUSLY MENTIONED AND SNOW IS RAPIDLY DEPARTING MUCH OF FORECAST AREA. ONLY NORTHERN AREAS WILL CONTINUE TO SEE ACCUMULATING SNOW THIS EVENING...AS THEY ARE ON THE EDGE OF THE DEFORMATION BAND OF SNOW ACROSS IOWA AND NEBRASKA. WILL ALLOW WARNINGS AND ADVISORY THAT END AT 9 PM ACROSS SOUTHERN HALF OF FORECAST AREA EXPIRE. WILL TAKE A LOOK CLOSER TO 9 PM TO SEE IF THE WARNING FOR NORTHWEST MISSOURI NEEDS TO BE EXTENDED UNTIL MIDNIGHT. PC 245 PM WED... CURRENTLY WATCHING REFLECTIVITY TAKE ON MESOSCALE BANDING CHARACTERISTICS ACROSS NORTH CENTRAL MISSOURI. THIS SEEMS TO BE RIGHT IN LINE WITH ETA/RUC PROGGED RAPID INCREASE IN VERTICAL MOTION AND INCREASING DIVERGENCE ALOFT. SATELLITE IMAGERY ALSO CONFIRMS JET STREAK CRASHING INTO WESTERN TEXAS...PUTTING MUCH OF EASTERN KANSAS AND WESTERN MISSOURI IN THE FAVORABLE LEFT EXIT REGION. BELIEVE SNOW WILL BECOME THE MORE PREDOMINANT WEATHER TYPE IN MOST AREAS NORTH OF A KANSAS CITY TO KIRKSVILLE LINE BY LATE AFTERNOON...AS THE SLOWLY DEEPENING COLD LAYER IS ENHANCE BY DIABATIC COOLING PROCESSES IN AREA OF VERY STRONG SYNOPTIC SCALE LIFT (ON THE ORDER OF 5-8 MBS-1). ETA/GFS BOTH DEPICT A TROWAL NEAR THE IOWA/MISSOURI BORDER AROUND 00Z THIS EVENING...THAT LIFTS NORTH INTO IOWA LATER IN THE NIGHT. HOWEVER...ETA ALSO DEPICTS SECONDARY TROWAL STRUCTURE FURTHER SOUTH IN NORTH CENTRAL MISSOURI. THIS SEEMS REASONABLE GIVEN CURRENT TRENDS...AND MAY BE REPRESENTED BY ENHANCED REFLECTIVITY ON KEAX IMAGERY. CURRENT FORECAST HAS THESE THOUGHTS IN MIND...WITH A 1-3 INCH STRIPE OF SNOW ACCUMULATION FROM KC TO KIRKSVILLE...AND 3-6 INCH SNOW TOTALS IN FAR NORTHWEST MISSOURI CLOSER TO 500MB LOW TRACK. LIGHTEST ACCUMULATIONS WILL BE FOUND ON THE SOUTH SIDE OF THE METRO. HAVE CONCERNS THAT SNOW MAY TAKE ON ADDITIONAL CONVECTIVE CHARACTERISTICS TOWARDS SUNSET...GIVEN THETA SURFACE FOLDING ON ETA CROSS SECTION NEAR 700 MB FROM OMAHA TO THE LAKE OF THE OZARKS. WILL WAIT AND SEE SINCE BEST SYNOPTIC SCALE LIFT MAY BE LIFTING NORTHWARD AHEAD OF THIS POTENTIAL INSTABILITY. PORTIONS OF CENTRAL AND WEST CENTRAL MISSOURI MAY SEE PRECIPITATION WIND DOWN BY EARLY EVENING...SO LATER SHIFTS WILL NEED TO MONITOR AND CANCEL ONGOING WARNINGS AS APPROPRIATE. SYSTEM SHOULD FINALLY BEGIN TO WIND DOWN LATE TONIGHT. WIND CHILLS WILL REMAIN BRUTAL THOUGH...WITH READINGS IN THE SINGLE DIGITS TO NEAR 10 BELOW ZERO IN FAR NORTHWEST MISSOURI. HUDSON ONGOING WINTER STORM EXPECTED TO BE EAST OF THE FORECAST AREA BY SUNRISE THURSDAY...HOWEVER EFFECTS WILL STILL BE FELT INTO THE DAY THURSDAY...AS SNOW/ICE COVER WILL KEEP MAX TEMPS THURSDAY IN THE TEENS ACROSS ALL BUT FAR SOUTHERN CWA. HAVE TRENDED TOWARDS LOW END OF GUIDANCE FOR THURS AFTERNOON AS WELL AS FRI MORNING...WHEN TEMPS LOOK TO RUN IN THE SINGLE DIGITS ACROSS NORTHWEST/NORTH CENTRAL MO. SHORTWAVE PROGGED TO TRANSLATE ACROSS REGION FOR FRIDAY. HAVE KEPT FORECAST DRY FOR NOW...ALTHOUGH WARM AIR ADVECTION AHEAD OF SHORTWAVE WILL ALLOW TEMPS TO MODERATE DURING THE DAY FRIDAY. HAVE REMOVED CHANCE POPS FOR SATURDAY...HOWEVER MODELS SUGGEST WESTERN LONGWAVE TO RELOAD FOR EARLY PORTION OF THE UPCOMING WEEK. WENT AHEAD AND INCLUDED CHANCE POPS FOR TUESDAY/WEDNESDAY TIMEFRAME. AT THIS TIME IS APPEARS PRECIP TYPE WILL REMAIN LIQUID. MS 1140 AM WED... UPDATED FORECASTS AND WARNINGS THIS MORNING TO REFLECT EVOLUTION OF SIGNIFICANT WINTER STORM. PRECIPITATION HAS CHANGED OVER TO A SLEET/SNOW MIX IN THE METRO AREA...WITH SNOW TO THE NORTH OF THE CITY. OLATHE CENTER WEATHER SERVICE UNIT REPORTED VISIBILITIES AROUND A HALF MILE IN HEAVY SLEET WITHIN THE PAST HOUR. EXPECT THIS NEXT BATCH OF PRECIPITATION TO REMAIN A MIX OF SLEET AND SNOW BEFORE TURNING OVER TO ALL SNOW THIS AFTERNOON IN FAR WESTERN MISSOURI. POINTS TO THE EAST WILL SEE A MIX OF FREEZING RAIN AND SLEET. AFTER THIS ROUND...A FINAL BLAST OF WINTRY PRECIPITATION APPEARS POSSIBLE PER THE 12Z ETA/GFS MODELS...AS MAIN SHORTWAVE EJECTS INTO THE PLAINS. CONSERVATIVE FORECASTS FROM MODEL/HPC QPF INDICATE A BAND OF 2-4 INCHES OF SNOW MAY FALL LATE THIS AFTERNOON INTO THE EVENING...ROUGHLY ALONG A LINE FROM KANSAS CITY TO KIRKSVILLE. SNOW AND WIND WILL PLAY HAVOC WITH THE EVENING COMMUTE. HAVE ADJUSTED AFTERNOON AND EVENING FORECAST TO REFLECT THIS THINKING...AND ALSO EXTENDED THE ONGOING WINTER STORM WARNINGS ANOTHER FEW HOURS. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 843 PM EST THU JAN 6 2005 .SHORT TERM (REST OF TONIGHT)... SW UPPER LEVEL FLOW OVER AREA WITH TRAILING END OF SHORTWAVE TROUGH OVER OH RIVER VALLEY. SURFACE COLD FRONT LOCATED FROM KHKY TO KATL AT 00Z...AND MAKING SLOW PROGRESS E. KGSP RADAR SHOWING NO PRECIPITAITON...AND POPS WILL REMAIN OUT OF FORECAST. SATELLITE IMAGERY SHOWS BKN CLOUDS OVER AREA...AND EXTENISVE CLOUD COVER UPSTREAM WELL INTO TN. HAVE INCREASED CLOUD COVER TONIGHT AND FRI MORNING AS SATELLITE IMAGERY DOES NOT HAVE BACK END OF MOISTURE AS FAR E AS MODELS. COLD ADVECTION A BIT BEHIND SCHEDULE...AND WILL RAISE MIN TEMPERATURES A DEGREE OR TWO. DEW POINT RUNNING SEVERAL DEGREES ABOVE FORECAST IN EAST...AND HAVE ADJUSTED TO FIT THIS TREND. UPDATED WIND WITH 21Z RUC...THOUGH LITTLE CHANGE FROM PREVIOUS WIND. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 203 PM EST THU JAN 6 2005 SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)... COLD FRONT EASILY VISIBLE ON SATELLITE...CURRENTLY STRETCHING FROM THE MOUTH OF THE MS RIVER ACROSS SRN AL AND CENTRAL GA TO THE SRN APPALACHIANS. RUC AND MESOETA BOTH AGREE THAT THE COVERAGE OF SHRA SHOULD DIMINISH EAST OF THE MTNS THIS AFTERNOON...HOWEVER...CHC COVERAGE SHOULD BE EXPECTED THROUGH 22Z. TONIGHT...THE FRONT SHOULD SLIDE OVER CENTRAL NC/SC/GA AND BECOME STATIONARY. BEHIND THE FRONT...CLOUDS WILL DIMINISH TO PC AND BRIEF CAA WILL TAKE PLACE BY 8Z...TEMPS FORECAST MAINLY IN THE 40S TONIGHT. FRI...MESOETA AND GFS BEGIN TO SHOW MORE DISAGREEMENT WITH THE FUTURE OF THE STALLED FRONT. THE GFS IS MORE AGGRESSIVE WILL PULLING THE FRONT NORTH AND ARRIVING OVER THE CWA WITH DEEP MOISTURE. THE MESOETA IS SLOWER BY AROUND 6 HRS AND IS ASSOCIATED WITH SIGNIFICANTLY LESS CLOUDINESS THAN THE GFS. AS A RESULT...THE MOS GUIDANCE SHOWS SOME LARGE DIFFERENCES BETWEEN TEMPS FRI THROUGH FRI NIGHT. WILL TAKE A COMPROMISE APPROACH BETWEEN THE TWO MODELS AND WILL SHOW FAVOR TO THE GFS GUIDANCE. ISENTROPIC LIFT AND JET DIVERGENCE WILL INCREASE OVER THE DEEP SOUTH FRI MORNING AND IS EXPECTED TO LIFT NORTH TO THE SRN APPALACHIANS BY FRI AFTERNOON. BOTH ETA AND GFS SHOW THE GREATEST QPF TO REMAIN OVER TN FRI. THE EXPECTED FRONTAL WAVE DEVELOPMENT OVER KY FRI NIGHT WILL HELP SWING THE AXIS OF RAINFALL EASTWARD FRI NIGHT AND EARLY SAT AS A COLD FRONT PASSES. COVERAGE OF THE SHRA OVER THE HIGHER TERRAIN SHOULD EASILY BECOME WIDESPREAD FRI NIGHT...HAVE INCREASED POPS TO CATE AND WILL USE LIKELY TO HIGH CHC FURTHER EAST. HIGH PRESSURE WILL ARRIVE SAT EVENING AND WILL KEEP THE FA DRY INTO MON. LONG TERM (MONDAY THROUGH THURSDAY)... LOW ARCTIC HEIGHTS REMAIN OVER WESTERN CANADA WITH LOBES OF ENERGY DROPPING INTO THE NW CONUS THROUGH THE EXTENDED PERIOD. FLOW OVER THE CWA WILL BEGIN AS ZONAL ON MON AND IS EXPECTED TO BECOME INCREASINGLY AMPLIFIED THROUGH THU. ECMWF AND GFS CONTINUE TO KEEP WAVES OF LOW PRESSURE PASSING WELL TO THE NORTH WITH SFC HIGH PRESSURE REMAINING OVER THE ATLANTIC. WILL EXPECT A SOUTH WIND TO CONTINUE THROUGHOUT THE EXTENDED PERIOD...ALONG WITH RICHER MOISTURE AND SPRING LIKE THICKNESSES. FOLLOWING HPC AND MEX GUIDANCE TEMPERATURES WILL REMAIN 10-20 DEGREES ABOVE NORMAL...ESPECIALLY WED AND THU AS STRONG MID-LEVEL RIDGE BUILDS ALONG THE EAST COAST. WILL INTRODUCE MTN CHCS WED AFTERNOON AS PLUME OF MOISTURE BUILDS OUT OF THE GULF AHEAD OF A APPROACHING COLD FRONT. COVERAGE OF FRONTAL SHRA SHOULD INCREASE ACROSS THE CWA THU...WILL LIMIT TO CHC AT THIS TIME. AVIATION... CIGS HAVE GRADUALLY BEEN RISING INTO THE EARLY AFTN HOURS. CURRENTLY MOST LOCATIONS HAVE MVRF CIGS...AND EXPECT THIS TO CONTINUE THROUGH LATE AFTN. THEREAFTER VEERING FLOW WL RESULT IN INCREASING DOWNSLOPE AND LLVL ADVECTION OF DRIER DWPTS WHICH WL RESULT IN THE GRADUAL DISSIPATION OF THE LOWER CIGS. THERE WL BE A BRIEF PERIOD OF REDUCED VISIBILITIES AND -SHRA ALONG THE SFC COLD FRONT...WHICH HAS BEEN HANDLED AT MOST SITES WITH A TEMPO GROUP. GUSTY SWLY WINDS WL GRADUALLY DIMINISH AS WELL AS STRONGER LLVL GRADIENT WORKS E OF THE REGION. HIGH CLOUDS SHOULD HANG ON THROUGH THE PERIOD. LATER TNGT EXPECT A FEW LOCATIONS...NOTABLY KAND...TO HAVE SOME FOG AS WNDS BECOME LGT. HAVE ALSO ADDED SOME MVFR FOG TO THE TAFS AT KCLT AND KHKY WHERE WNDS WL BE LIGHTER FOR A LONGER PERIOD OF TIME. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM (UPDATE)...JAT sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 203 PM EST THU JAN 6 2005 .SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)... COLD FRONT EASILY VISIBLE ON SATELLITE...CURRENTLY STRETCHING FROM THE MOUTH OF THE MS RIVER ACROSS SRN AL AND CENTRAL GA TO THE SRN APPALACHIANS. RUC AND MESOETA BOTH AGREE THAT THE COVERAGE OF SHRA SHOULD DIMINISH EAST OF THE MTNS THIS AFTERNOON...HOWEVER...CHC COVERAGE SHOULD BE EXPECTED THROUGH 22Z. TONIGHT...THE FRONT SHOULD SLIDE OVER CENTRAL NC/SC/GA AND BECOME STATIONARY. BEHIND THE FRONT...CLOUDS WILL DIMINISH TO PC AND BRIEF CAA WILL TAKE PLACE BY 8Z...TEMPS FORECAST MAINLY IN THE 40S TONIGHT. FRI...MESOETA AND GFS BEGIN TO SHOW MORE DISAGREEMENT WITH THE FUTURE OF THE STALLED FRONT. THE GFS IS MORE AGGRESSIVE WILL PULLING THE FRONT NORTH AND ARRIVING OVER THE CWA WITH DEEP MOISTURE. THE MESOETA IS SLOWER BY AROUND 6 HRS AND IS ASSOCIATED WITH SIGNIFICANTLY LESS CLOUDINESS THAN THE GFS. AS A RESULT...THE MOS GUIDANCE SHOWS SOME LARGE DIFFERENCES BETWEEN TEMPS FRI THROUGH FRI NIGHT. WILL TAKE A COMPROMISE APPROACH BETWEEN THE TWO MODELS AND WILL SHOW FAVOR TO THE GFS GUIDANCE. ISENTROPIC LIFT AND JET DIVERGENCE WILL INCREASE OVER THE DEEP SOUTH FRI MORNING AND IS EXPECTED TO LIFT NORTH TO THE SRN APPALACHIANS BY FRI AFTERNOON. BOTH ETA AND GFS SHOW THE GREATEST QPF TO REMAIN OVER TN FRI. THE EXPECTED FRONTAL WAVE DEVELOPMENT OVER KY FRI NIGHT WILL HELP SWING THE AXIS OF RAINFALL EASTWARD FRI NIGHT AND EARLY SAT AS A COLD FRONT PASSES. COVERAGE OF THE SHRA OVER THE HIGHER TERRAIN SHOULD EASILY BECOME WIDESPREAD FRI NIGHT...HAVE INCREASED POPS TO CATE AND WILL USE LIKELY TO HIGH CHC FURTHER EAST. HIGH PRESSURE WILL ARRIVE SAT EVENING AND WILL KEEP THE FA DRY INTO MON. && .LONG TERM (MONDAY THROUGH THURSDAY)... LOW ARCTIC HEIGHTS REMAIN OVER WESTERN CANADA WITH LOBES OF ENERGY DROPPING INTO THE NW CONUS THROUGH THE EXTENDED PERIOD. FLOW OVER THE CWA WILL BEGIN AS ZONAL ON MON AND IS EXPECTED TO BECOME INCREASINGLY AMPLIFIED THROUGH THU. ECMWF AND GFS CONTINUE TO KEEP WAVES OF LOW PRESSURE PASSING WELL TO THE NORTH WITH SFC HIGH PRESSURE REMAINING OVER THE ATLANTIC. WILL EXPECT A SOUTH WIND TO CONTINUE THROUGHOUT THE EXTENDED PERIOD...ALONG WITH RICHER MOISTURE AND SPRING LIKE THICKNESSES. FOLLOWING HPC AND MEX GUIDANCE TEMPERATURES WILL REMAIN 10-20 DEGREES ABOVE NORMAL...ESPECIALLY WED AND THU AS STRONG MID-LEVEL RIDGE BUILDS ALONG THE EAST COAST. WILL INTRODUCE MTN CHCS WED AFTERNOON AS PLUME OF MOISTURE BUILDS OUT OF THE GULF AHEAD OF A APPROACHING COLD FRONT. COVERAGE OF FRONTAL SHRA SHOULD INCREASE ACROSS THE CWA THU...WILL LIMIT TO CHC AT THIS TIME. && .AVIATION... CIGS HAVE GRADUALLY BEEN RISING INTO THE EARLY AFTN HOURS. CURRENTLY MOST LOCATIONS HAVE MVRF CIGS...AND EXPECT THIS TO CONTINUE THROUGH LATE AFTN. THEREAFTER VEERING FLOW WL RESULT IN INCREASING DOWNSLOPE AND LLVL ADVECTION OF DRIER DWPTS WHICH WL RESULT IN THE GRADUAL DISSIPATION OF THE LOWER CIGS. THERE WL BE A BRIEF PERIOD OF REDUCED VISIBILITIES AND -SHRA ALONG THE SFC COLD FRONT...WHICH HAS BEEN HANDLED AT MOST SITES WITH A TEMPO GROUP. GUSTY SWLY WINDS WL GRADUALLY DIMINISH AS WELL AS STRONGER LLVL GRADIENT WORKS E OF THE REGION. HIGH CLOUDS SHOULD HANG ON THROUGH THE PERIOD. LATER TNGT EXPECT A FEW LOCATIONS...NOTABLY KAND...TO HAVE SOME FOG AS WNDS BECOME LGT. HAVE ALSO ADDED SOME MVFR FOG TO THE TAFS AT KCLT AND KHKY WHERE WNDS WL BE LIGHTER FOR A LONGER PERIOD OF TIME. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM/LONG TERM...NED AVIATION...BPM sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1000 AM EST THU JAN 6 2005 .SHORT TERM /TODAY/...HIGH PRES THAT WAS ANCHORED JUST OUTSIDE THE COASTAL WATERS NOW PUSHING WELL INTO THE ATLC AS THE STRONG FNTL SYS OVER THE CENTRAL PART OF THE COUNTRY PUSHES EWD. AS FNT APCHS CLOUDS WILL CONTINUE TO INCRS...ESP FOR INLAND COUNTIES. ALREADY SEEING FAIRLY SOLID CLOUD SHIELD OVER THE MIDLANDS AND UPSTATE REGIONS OF SC AND OVER MUCH OF GA THAT IS PROGRESSING TWD THE CWFA. TIME HEIGHTS FOR INLAND LOCATIONS SHOW THICKER MOISTURE EARLIER THAN COASTAL LOCATIONS AND GOING ZFP HAS THE IDEA OF INLAND MOCLDY/COASTAL PCLDY HANDLED WELL. WILL BE INTERESTING TO SEE HOW THIS PLAYS INTO HIGH TEMPS TDA AS COMPARED TO SWLY WAA. RECORD HIGHS AT BOTH CHS AND SAV ARE 78 TDA AND THESE VALUES WILL CERTAINLY BE FLIRTED WITH. OVERALL VALUES FOR ZONES LOOK GOOD. AS FOR WINDS... PRES GRAD WILL TIGHTEN THRU THE AFTN BETWEEN THE SLOWLY EXITING HIGH AND THE STEADILY APCHG FNTL BNDRY. WILL CLEAN UP WORDING AND RUN WITH HIGHER AFTN VALUES. && .LAKE WINDS...WINDS AT PINEVILLE HAVE COME IN AT 15-20 MPH THE PAST 2 HRS. 12Z KCHS SOUNDING SHOWS 30 KT BETWEEN 1-2 KFT WHICH SEEMS TO BE MIXING DOWN JUST ENOUGH DESPITE COLD WATER TEMPS AND WARMER AIR ALOFT. RUC 925MB WINDS ARE ONLY 10-15 KT WHICH SEEMS UNDERDONE AND HAS ALSO INITIALIZED WITH LOWER WIND SPEEDS THAN OBS. WITH THE INCRD PRES GRAD EXPECTED THIS AFTN...LWA CRITERIA MAY JUST BE REACHED SO WILL ISSUE LWA WITH MINIMAL CRITERIA. && .MARINE...S-SW FLOW WILL INCRS THRU THE AFTN AS PRES GRAD INCRS. GOING CWF HAS THIS HANDLED WELL. WAVE HEIGHTS LOOK RIGHT ON TRACK. ONLY COSMETIC WORDING CHANGES NEEDED AND WILL KEEP SCEC HEADLINE FOR CHS HARBOR. && .AVIATION...VFR TO PREVAIL THROUGH 07/08Z WITH UPR LVL SCT/BKN CLOUDS AND MIDLVL SCT CLOUDS. AFTER 07/08Z...MVFR TO IFR LOW STRATUS LOOKS TO BE A CONCERN...ESP AT KSAV. WILL MAINTAIN BKN CIGS AOB 500FT FOR TMRW MRNG. INCRG WIND SPEEDS WITH HIGHER GUSTS LOOK TO OCCUR THIS AFTN AND GOING 06/12Z TAFS HAVE THIS ADVERTISED. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...LAKE WIND ADVISORY SCZ045. MARINE...NONE. && $$ JPC sc AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 825 PM MST THU JAN 5 2005 .DISCUSSION...03Z SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY LOCATED FROM NORTH CENTRAL NORTH DAKOTA TO SOUTH CENTRAL MONTANA...WITH LOW STRATUS DECK AND SOME LIGHT SNOW OCCURING BEHIND THE FRONT. THE FRONT IS ABOUT 3 HOURS QUICKER THAN SHOWN ON THE 00Z ETA...MORE IN LINE WITH THE CURRENT RUC SOLUTION. HAVE ALREADY UPDATED FORECAST TO ADJUST TIMING OF LOW CLOUDS INTO THE FORECAST AREA AND TO ADD A CHANCE OF SNOW OVER PORTIONS OF NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH DAKOTA FOR LATE TONIGHT AND FRIDAY MORNING. && .AVIATION...A SURFACE FRONT WILL WILL ENTER NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH DAKOTA LATE THIS EVENING...AND WILL MOVE SOUTHEASTWARD ACROSS THE REST OF THE AREA TONIGHT INTO FRIDAY MORNING. LOW STRATUS WILL FOLLOW THE FRONT...LEADING TO MAINLY MVFR..WITH AREAS OF IFR CONDITIONS. THERE WILL BE A CHANCE OF LIGHT SNOW OVER PORTIONS OF NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH DAKOTA LATE TONIGHT INTO FRIDAY MORNING. && .UNR...WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. $$ sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA ISSUED BY NATIONAL WEATHER SERVICE RALEIGH NC 215 PM EST THU JAN 6 2005 .SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)... FOR THE IMMEDIATE SHORT TERM...THIS EVENING...WILL ONLY LEAVE IN A FEW SHOWERS BASED ON RADAR TRENDS...MAINLY EAST. WILL KEEP SOME GUSTS IN HIGHER TERRAIN TONIGHT. SOME DECREASE IN CLOUDS OVERNIGHT/EARLY FRIDAY AHEAD OF NEXT SYSTEM. OVERCAST CONDITIONS RETURNING BY FRIDAY AFTERNOON. S/W MOVING EAST IN FAST FLOW WITH SURFACE LOW SPINNING UP IN TENNESSEE VALLEY LIFTING NORTHEAST LATE FRIDAY NIGHT/SATURDAY MORNING. BOTH ETA/GFS IN AGREEMENT ON THIS AND FAIRLY CONSISTENT PAST COUPLE OF DAYS. BEST DYNAMICS WITH THIS SYSTEM TO AFFECT CWA LATE FRIDAY NIGHT INTO SATURDAY MORNING. WILL SHOW TEMPERATURES RISING SATURDAY NIGHT. ADDITIONALLY 40-50KT LLJ MOVING ACROSS DURING THIS TIME. WILL HAVE WIND GUSTS SIMILAR TO TODAY. ENDING PRECIPITATION FROM WEST TO EAST IN THE AFTERNOON. CLEARING SATURDAY NIGHT WITH LOWS DIPPING INTO THE 30S. HIGHS WILL RANGE FROM LOWER 50S NORTHWEST TO LOWER 60S SOUTHEAST PIEDMONT. && .LONG TERM (MONDAY THROUGH THURSDAY)... NOT MUCH CHANGE FROM GOING TREND. MILD SOUTHWEST FLOW. ANOTHER FRONT APPROACHES BY LATE WEEK. WILL INTRODUCE SMALL CHANCE THURSDAY. && .AVIATION (DANVILLE ONLY)... EXPECT OCCASIONAL MVFR CEILINGS WITH PERHAPS A SPRINKLE OF LIGHT RAIN THROUGH AROUND 00Z...WITH HIGH CLOUDINESS LATER AFTERWARD LINGERING FRIDAY. WEST WINDS WILL BE DIMINISHING AS EVENING APPROACHES...WITH SUSTAINED 12 TO 14 KTS AND GUSTS TO 20KT UNTIL AROUND 22Z...THEN FURTHER DIMINISHING FROM THE NORTHWEST TONIGHT. && .PREVIOUS DISCUSSION... (ISSUED 1001 AM EST THU JAN 6 2005) SHORT TERM (REST OF TODAY)... LATE MORNING UPDATE TO CLEAN UP WORDING TO REMOVE FOG AND REFERENCE TO MORNING PERIOD. PERIOD OF GUSTY WINDS...NOT ENOUGH FOR ADVISORY FOR NOW. KEEP LIKELY POPS IN MOUNTAINS. PREVIOUS DISCUSSION... (ISSUED 647 AM EST THU JAN 6 2005) AVIATION... A WARM FRONT IS MOVING NORTH OUT OF THE REGION THIS MORNING. WINDS AT ROA ND LYH ARE TURNING BACK TO THE SOUTHEAST AND WILL GRADUALLY BECOME SE THIS MORNING. AS THE FNT MOVES NORTH...CONDITIONS WILL IMPROVE TO VFR. BAND OF SHRA COMING OUT OF THE OH VALLEY WILL REACH BLF AND LWB LATE THIS MORNING. CONDITIONS WITH DROP TO MVFR WITH THE SHRA. THE RAIN WILL WEAKEN AS IT CROSSES THE MOUNTAINS...BUT LIGHT SHRA WL REACH ROA...LYH AND DAN DURING THE AFTERNOON. A COLD FRONT WILL CROSS THE FA THIS AFTERNOON SHARPLY DROPPING TEMPERATURES AND KEEPING IFR TO MVFR CIGS BACK INTO SOUTHEAST WV. WINDS WILL INCREASE THIS AFTERNOON AND EVENING BEHIND THE FRONT BUT WILL DIMINISH BY 12Z AS THE SFC HIGH WL BE CENTERED OVER THE REGION AT THAT TIME. PREVIOUS DISCUSSION... (ISSUED 250 AM EST THU JAN 6 2005) SHORT TERM (TODAY THROUGH SATURDAY)... UPPER RIDGE IS SHIFTING WEST BY SUN WITH US IN ZONAL PTTN. FRONT IS SLOWER ON ETA/GFS/RUC NOW. WL REFLECT SLOWER TIMING IN WINDS AND IN ARRIVAL OF PCPN. CHC WL BE REMOVED FROM EAST OF THE BLUE RIDGE THIS MORNING AND IN THE FAR EAST UNTIL MID AFTERNOON. WARM FNT SHUD BE BACK NORTH OF THE CWA EARLY. THEN 8H TEMPS START DROPPING IN THE WEST AFT 12Z BUT NOT AT DAN AND LYH UNTIL AFT 18Z. WL HAVE AFTN TEMPS FALLING IN THE WEST. VERY LITTLE 7H UVV WITH THE FNT ON THE GFS TYPICAL OF THE LOW LVL WLY FLOW. WL KEEP LOWEST POPS IN THE PIEDMONT. BASED ON RH PROGS SHUD HAVE SCT-BKN CLOUD COVER IN THE EAST FROM 00Z-06Z. SFC FNT GETS DOWN TO NC/SC BORDER BY 12Z FRI. STILL GOOD PRES RISES TNGT BUT 8H JET ONLY 30-40 KTS BEHIND THE FNT SO NO CHANGES NEEDED TO POST FRONTAL WINDS. 7-3RH INCREASES AGAIN FROM THE SOUTH FRI MORN.WL BE CLOUDY ACROSS ENTIRE CWA BY 18Z. COLUMN SATURATES DOWN TO LOW LVL AND ENOUGH TO RAIN BY AFTERNOON. BY FRI NGT AREA IN RRQ OF UPPER JET LATE. WL ADD A PERIOD OF MODERATE RAIN IN THE WEST WHEN GOOD JET DYNAMICS WILL BE AIDED BY DECENT 300-310K ISENTROPIC LIFT. BIGGEST DIFFERENCE IN THE MODELS IS THE AMOUNT OF INFLOW OFF THE GULF. 8H RIDGING NOT AS STRONG OVER THE GULF ON THE GFS ALLOWING FOR BETTER TRANSPORT OF GULF MOISTURE. WL BE BRINGING UP PWINS AROUND AROUND 1.5 INCHES. GFS IS JUST SLIGHTLY FARTEHR EAST AND SOUTH WITH THE AXIS OF HEAVIEST QPF. WL HAVE THE LARGEST QPF IN THE GREENBRIER VALLEY FRI NIGHT. SHRTWV COMING FROM CURRENT POSN IN IDAHO CROSSES CWA SAT MORN. SFC LOW CROSSES VA SAT MORN. DEEP RH MOVES EAST BY 18Z BUT DOES NOT DRY OUT BELOW 8H UNTIL SUN MORN SO WL STAY PESSIMISTIC ON THE CLOUDS COVER. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... CUT BACK POPS SATURDAY NIGHT AS TIMING APPEARS FASTER WITH MOISTURE. ELECTED TO SLOWLY DECREASED CLOUD COVER SATURDAY NIGHT. DECIDED TO KEEP LOW TEMPERATURES SUNDAY NIGHT MILDER AS WARM AIR ADVANCING NORTH. RAISED UP HIGH TEMPERATURES A FEW DEGREES ON MONDAY AND TUESDAY WITH SOUTHWEST FLOW. ADDED LIGHT POPS TO FAR WEST ON MONDAY NIGHT AND TUESDAY. NUDGED POPS IN WEST UP FOR WEDNESDAY. AVIATION... SFC OBS AND MSAS DATA SHOWED BACK DOOR FRONT MOVED INTO EASTERN SECTIONS OF VA THIS MORNING. THIS BOUNDARY WILL CREATE AREAS OF LOW CLOUDS AND FOG THIS MORNING WITH IFR/LIFR CEILINGS AND VISIBILITIES. LATE THIS MORNING IT SHOULD MIX OUT IN ADVANCE OF THE COLD FRONT. EXPECT AIRPORTS TO SEE CEILINGS DROP TO MVFR ACROSS WEST VIRGINIA MOUNTAINS THIS MORNING...THEN MVFR AT KROA...KLYH...AND KDAN AROUND 09Z TO 12Z. COLD FRONT WITH MVFR AND ISOLD IFR CONDITIONS POISED TO MOVE INTO THE WESTERN CWA AROUND 18Z TODAY...MOVING INTO THE EASTERN FORECAST AREA AROUND 00Z THURSDAY EVENING. BEST CHANCES OF RAIN WILL OCCUR IN THE WESTERN MOUNTAINS. WITH FRONTAL PASSAGE...EXPECT WINDS TO INCREASE...WITH GUSTS UP TO 25KTS BY THIS AFTERNOON AND EVENING. WEST WINDS SHOULD DRY IT OUT IN THE WAKE OF THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ TDP/RA va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA ISSUED BY NATIONAL WEATHER SERVICE RALEIGH NC 1001 AM EST THU JAN 6 2005 .SHORT TERM (REST OF TODAY)... LATE MORNING UPDATE TO CLEAN UP WORDING TO REMOVE FOG AND REFERENCE TO MORNING PERIOD. PERIOD OF GUSTY WINDS...NOT ENOUGH FOR ADVISORY FOR NOW. KEEP LIKELY POPS IN MOUNTAINS. && .PREVIOUS DISCUSSION... (ISSUED 647 AM EST THU JAN 6 2005) AVIATION... A WARM FRONT IS MOVING NORTH OUT OF THE REGION THIS MORNING. WINDS AT ROA ND LYH ARE TURNING BACK TO THE SOUTHEAST AND WILL GRADUALLY BECOME SE THIS MORNING. AS THE FNT MOVES NORTH...CONDITIONS WILL IMPROVE TO VFR. BAND OF SHRA COMING OUT OF THE OH VALLEY WILL REACH BLF AND LWB LATE THIS MORNING. CONDITIONS WITH DROP TO MVFR WITH THE SHRA. THE RAIN WILL WEAKEN AS IT CROSSES THE MOUNTAINS...BUT LIGHT SHRA WL REACH ROA...LYH AND DAN DURING THE AFTERNOON. A COLD FRONT WILL CROSS THE FA THIS AFTERNOON SHARPLY DROPPING TEMPERATURES AND KEEPING IFR TO MVFR CIGS BACK INTO SOUTHEAST WV. WINDS WILL INCREASE THIS AFTERNOON AND EVENING BEHIND THE FRONT BUT WILL DIMINISH BY 12Z AS THE SFC HIGH WL BE CENTERED OVER THE REGION AT THAT TIME. PREVIOUS DISCUSSION... (ISSUED 250 AM EST THU JAN 6 2005) SHORT TERM (TODAY THROUGH SATURDAY)... UPPER RIDGE IS SHIFTING WEST BY SUN WITH US IN ZONAL PTTN. FRONT IS SLOWER ON ETA/GFS/RUC NOW. WL REFLECT SLOWER TIMING IN WINDS AND IN ARRIVAL OF PCPN. CHC WL BE REMOVED FROM EAST OF THE BLUE RIDGE THIS MORNING AND IN THE FAR EAST UNTIL MID AFTERNOON. WARM FNT SHUD BE BACK NORTH OF THE CWA EARLY. THEN 8H TEMPS START DROPPING IN THE WEST AFT 12Z BUT NOT AT DAN AND LYH UNTIL AFT 18Z. WL HAVE AFTN TEMPS FALLING IN THE WEST. VERY LITTLE 7H UVV WITH THE FNT ON THE GFS TYPICAL OF THE LOW LVL WLY FLOW. WL KEEP LOWEST POPS IN THE PIEDMONT. BASED ON RH PROGS SHUD HAVE SCT-BKN CLOUD COVER IN THE EAST FROM 00Z-06Z. SFC FNT GETS DOWN TO NC/SC BORDER BY 12Z FRI. STILL GOOD PRES RISES TNGT BUT 8H JET ONLY 30-40 KTS BEHIND THE FNT SO NO CHANGES NEEDED TO POST FRONTAL WINDS. 7-3RH INCREASES AGAIN FROM THE SOUTH FRI MORN.WL BE CLOUDY ACROSS ENTIRE CWA BY 18Z. COLUMN SATURATES DOWN TO LOW LVL AND ENOUGH TO RAIN BY AFTERNOON. BY FRI NGT AREA IN RRQ OF UPPER JET LATE. WL ADD A PERIOD OF MOSERATE RAIN IN THE WEST WHEN GOOD JET DYNAMICS WILL BE AIDED BY DECENT 300-310K ISENTROPIC LIFT. BIGGEST DIFFERENCE IN THE MODELS IS THE AMOUNT OF INFLOW OFF THE GULF. 8H RIDGING NOT AS STRONG OVER THE GULF ON THE GFS ALLOWING FOR BETTER TRANSPORT OF GULF MOISTURE. WL BE BRINGING UP PWINS AROUND AROUND 1.5 INCHES. GFS IS JUST SLIGHTLY FARTEHR EAST AND SOUTH WITH THE AXIS OF HEAVIEST QPF. WL HAVE THE LARGEST QPF IN THE GREENBRIER VALLEY FRI NIGHT. SHRTWV COMING FROM CURRENT POSN IN IDAHO CROSSES CWA SAT MORN. SFC LOW CROSSES VA SAT MORN. DEEP RH MOVES EAST BY 18Z BUT DOES NOT DRY OUT BELOW 8H UNTIL SUN MORN SO WL STAY PESSIMISTIC ON THE CLOUDS COVER. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... CUT BACK POPS SATURDAY NIGHT AS TIMING APPEARS FASTER WITH MOISTURE. ELECTED TO SLOWLY DECREASED CLOUD COVER SATURDAY NIGHT. DECIDED TO KEEP LOW TEMPERATURES SUNDAY NIGHT MILDER AS WARM AIR ADVANCING NORTH. RAISED UP HIGH TEMPERATURES A FEW DEGREES ON MONDAY AND TUESDAY WITH SOUTHWEST FLOW. ADDED LIGHT POPS TO FAR WEST ON MONDAY NIGHT AND TUESDAY. NUDGED POPS IN WEST UP FOR WEDNESDAY. AVIATION... SFC OBS AND MSAS DATA SHOWED BACK DOOR FRONT MOVED INTO EASTERN SECTIONS OF VA THIS MORNING. THIS BOUNDARY WILL CREATE AREAS OF LOW CLOUDS AND FOG THIS MORNING WITH IFR/LIFR CEILINGS AND VISIBILITIES. LATE THIS MORNING IT SHOULD MIX OUT IN ADVANCE OF THE COLD FRONT. EXPECT AIRPORTS TO SEE CEILINGS DROP TO MVFR ACROSS WEST VIRGINIA MOUNTAINS THIS MORNING...THEN MVFR AT KROA...KLYH...AND KDAN AROUND 09Z TO 12Z. COLD FRONT WITH MVFR AND ISOLD IFR CONDITIONS POISED TO MOVE INTO THE WESTERN CWA AROUND 18Z TODAY...MOVING INTO THE EASTERN FORECAST AREA AROUND 00Z THURSDAY EVENING. BEST CHANCES OF RAIN WILL OCCUR IN THE WESTERN MOUNTAINS. WITH FRONTAL PASSAGE...EXPECT WINDS TO INCREASE...WITH GUSTS UP TO 25KTS BY THIS AFTERNOON AND EVENING. WEST WINDS SHOULD DRY IT OUT IN THE WAKE OF THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ RA va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 647 AM EST THU JAN 6 2005 .AVIATION... A WARM FRONT IS MOVING NORTH OUT OF THE REGION THIS MORNING. WINDS AT ROA ND LYH ARE TURNING BACK TO THE SOUTHEAST AND WILL GRADUALLY BECOME SE THIS MORNING. AS THE FNT MOVES NORTH...CONDITIONS WILL IMPROVE TO VFR. BAND OF SHRA COMING OUT OF THE OH VALLEY WILL REACH BLF AND LWB LATE THIS MORNING. CONDITIONS WITH DROP TO MVFR WITH THE SHRA. THE RAIN WILL WEAKEN AS IT CROSSES THE MOUNTAINS...BUT LIGHT SHRA WL REACH ROA...LYH AND DAN DURING THE AFTERNOON. A COLD FRONT WILL CROSS THE FA THIS AFTERNOON SHARPLY DROPPING TEMPERATURES AND KEEPING IFR TO MVFR CIGS BACK INTO SOUTHEAST WV. WINDS WILL INCREASE THIS AFTERNOON AND EVENING BEHIND THE FRONT BUT WILL DIMINISH BY 12Z AS THE SFC HIGH WL BE CENTERED OVER THE REGION AT THAT TIME. && .PREVIOUS DISCUSSION... (ISSUED 250 AM EST THU JAN 6 2005) SHORT TERM (TODAY THROUGH SATURDAY)... UPPER RIDGE IS SHIFTING WEST BY SUN WITH US IN ZONAL PTTN. FRONT IS SLOWER ON ETA/GFS/RUC NOW. WL REFLECT SLOWER TIMING IN WINDS AND IN ARRIVAL OF PCPN. CHC WL BE REMOVED FROM EAST OF THE BLUE RIDGE THIS MORNING AND IN THE FAR EAST UNTIL MID AFTERNOON. WARM FNT SHUD BE BACK NORTH OF THE CWA EARLY. THEN 8H TEMPS START DROPPING IN THE WEST AFT 12Z BUT NOT AT DAN AND LYH UNTIL AFT 18Z. WL HAVE AFTN TEMPS FALLING IN THE WEST. VERY LITTLE 7H UVV WITH THE FNT ON THE GFS TYPICAL OF THE LOW LVL WLY FLOW. WL KEEP LOWEST POPS IN THE PIEDMONT. BASED ON RH PROGS SHUD HAVE SCT-BKN CLOUD COVER IN THE EAST FROM 00Z-06Z. SFC FNT GETS DOWN TO NC/SC BORDER BY 12Z FRI. STILL GOOD PRES RISES TNGT BUT 8H JET ONLY 30-40 KTS BEHIND THE FNT SO NO CHANGES NEEDED TO POST FRONTAL WINDS. 7-3RH INCREASES AGAIN FROM THE SOUTH FRI MORN.WL BE CLOUDY ACROSS ENTIRE CWA BY 18Z. COLUMN SATURATES DOWN TO LOW LVL AND ENOUGH TO RAIN BY AFTERNOON. BY FRI NGT AREA IN RRQ OF UPPER JET LATE. WL ADD A PERIOD OF MOSERATE RAIN IN THE WEST WHEN GOOD JET DYNAMICS WILL BE AIDED BY DECENT 300-310K ISENTROPIC LIFT. BIGGEST DIFFERENCE IN THE MODELS IS THE AMOUNT OF INFLOW OFF THE GULF. 8H RIDGING NOT AS STRONG OVER THE GULF ON THE GFS ALLOWING FOR BETTER TRANSPORT OF GULF MOISTURE. WL BE BRINGING UP PWINS AROUND AROUND 1.5 INCHES. GFS IS JUST SLIGHTLY FARTEHR EAST AND SOUTH WITH THE AXIS OF HEAVIEST QPF. WL HAVE THE LARGEST QPF IN THE GREENBRIER VALLEY FRI NIGHT. SHRTWV COMING FROM CURRENT POSN IN IDAHO CROSSES CWA SAT MORN. SFC LOW CROSSES VA SAT MORN. DEEP RH MOVES EAST BY 18Z BUT DOES NOT DRY OUT BELOW 8H UNTIL SUN MORN SO WL STAY PESSIMISTIC ON THE CLOUDS COVER. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... CUT BACK POPS SATURDAY NIGHT AS TIMING APPEARS FASTER WITH MOISTURE. ELECTED TO SLOWLY DECREASED CLOUD COVER SATURDAY NIGHT. DECIDED TO KEEP LOW TEMPERATURES SUNDAY NIGHT MILDER AS WARM AIR ADVANCING NORTH. RAISED UP HIGH TEMPERATURES A FEW DEGREES ON MONDAY AND TUESDAY WITH SOUTHWEST FLOW. ADDED LIGHT POPS TO FAR WEST ON MONDAY NIGHT AND TUESDAY. NUDGED POPS IN WEST UP FOR WEDNESDAY. AVIATION... SFC OBS AND MSAS DATA SHOWED BACK DOOR FRONT MOVED INTO EASTERN SECTIONS OF VA THIS MORNING. THIS BOUNDARY WILL CREATE AREAS OF LOW CLOUDS AND FOG THIS MORNING WITH IFR/LIFR CEILINGS AND VISIBILITIES. LATE THIS MORNING IT SHOULD MIX OUT IN ADVANCE OF THE COLD FRONT. EXPECT AIRPORTS TO SEE CEILINGS DROP TO MVFR ACROSS WEST VIRGINIA MOUNTAINS THIS MORNING...THEN MVFR AT KROA...KLYH...AND KDAN AROUND 09Z TO 12Z. COLD FRONT WITH MVFR AND ISOLD IFR CONDITIONS POISED TO MOVE INTO THE WESTERN CWA AROUND 18Z TODAY...MOVING INTO THE EASTERN FORECAST AREA AROUND 00Z THURSDAY EVENING. BEST CHANCES OF RAIN WILL OCCUR IN THE WESTERN MOUNTAINS. WITH FRONTAL PASSAGE...EXPECT WINDS TO INCREASE...WITH GUSTS UP TO 25KTS BY THIS AFTERNOON AND EVENING. WEST WINDS SHOULD DRY IT OUT IN THE WAKE OF THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ AMS va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 300 PM CST THU JAN 6 2005 .DISCUSSION...FORECAST FOCUS ON TEMPERATURES WITH FRESH SNOW COVER. IN THE SHORT TERM...WEATHER NIL AS RUC/NGM/ETA/GFS PROGS SLIDE RIDE HIGH PRESSURE RIDGE ACROSS CWA OVERNIGHT. EXPECT SURFACE WINDS TO DECOUPLE. WITH GOOD RADIATIONAL COOLING OVER THE FRESH SNOW COVER WILL SEE TEMPERATURES DROP TO SINGLE DIGITS DESPITE CURRENT DEW POINTS IN THE TEENS. IN THE FAR TERM...WEATHER NIL FOR MOST PART AS WEATHER SYSTEMS REMAIN AND SOMEWHAT STARVED FOR DEEP MOISTURE. GFS TRIES TO DEVELOP LIGHT PRECIPITATION IN DECENT WARM AIR ADVECTION PATTERN FOR SUNDAY...BUT HAVE OPTED TO LEAVE DRY AS SHOWN BY ETA AND EVALUATION OF TIME CROSS SECTIONS. HAVE TEMPERED TEMPERATURE FORECAST FOR FRIDAY THROUGH SATURDAY WITH SNOW COVER IN MIND. DESPITE GOOD LOW LEVEL WARM ADVECTION AGREE WITH BUFKIT SOLUTIONS OF DECENT LOW LEVEL INVERSIONS NEAR THE SURFACE... ESPECIALLY AT NIGHT WHEN WINDS DECOUPLE. WITH FAIRLY PERSISTENT SOUTHERLY FLOW IN FORECAST...WILL ALSO NEED TO WATCH FOR FOG/STRATUS FORMATION AS MELTING SNOW AND INCREASING LOW LEVEL MOISTURE INTERACT IN FUTURE. && .MKX WATCHES/WARNINGS/ADVISORIES...NONE. $$ ZAJDEL wi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 955 AM CST THU JAN 6 2005 .DISCUSSION...FORECAST FOCUS ON ENDING OF WINTER STORM IN THE SHORT TERM...WILL ALLOW WINTER STORM WARNING TO EXPIRE ALTHOUGH SOME LAKE EFFECT/ENHANCEMENT CONTINUES TO HUG SHORELINE. EFFECTS OF LAKE SNOW TO BE MINIMAL AT BEST. WEATHER SYSTEM NOW OVER LAKE ERIE AND RUC PROG SHOWS CONTINUED BUILDING OF HIGH OVER CWA WITH TIME. && .MKX WATCHES/WARNINGS/ADVISORIES...NONE. $$ ZAJDEL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 930 PM MST THU JAN 6 2005 .UPDATE...FOG IS GRADUALLY EXPANDING ACROSS MOST OF THE AREA WITH GREATEST REDUCTION IN VISIBILITY ALONG AND SOUTH OF INTERSTATE 70. THIS MATCHES UP PRETTY WELL WITH RUC 925-850 RELATIVE HUMIDITY JUST AHEAD OF SURFACE LOW. FOR THE REMAINDER OF THE NIGHT THIS BLOB OF MOISTURE SLOWLY MOVES EAST WITH THE SURFACE LOW. WILL UPDATE FORECAST TO HIT FOG HARDER AND GO WIDESPREAD. RECENT CALL FROM TRIBUNE AREA (GREELEY COUNTY) REVEALED 1/2 VISIBILITY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...DENSE FOG ADVISORY IN EFFECT UNTIL 11 PM MST FOR CHEYENNE AND KIT CARSON COUNTIES OF COLORADO. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 310 AM EST FRI JAN 7 2005 .SHORT TERM...FRIDAY AND FRIDAY NIGHT FLURRIES DIMINISHING QUICKLY WEST OF MBS AND FNT AS 850 TEMPERATURES CONTINUE TO WARM AND INVERSION HEIGHTS FALL TO LESS THAN 3K FT OVER LAKE MICHIGAN...SO WILL NOT MENTION ANY FLURRIES EARLY THIS MORNING IN ZONE PACKAGE. LARGE AREA OF LOW CLOUDS SNEAKING IN UNDER INVERSION THOUGH AND FILLING IN THE FEW HOLES THAT DEVELOPED OVERNIGHT. LOOKS LIKE 40KM RUC HAS A GOOD HANDLE ON SOUTHERN EXTENT OF LOW CLOUDS OVER THE OHIO VALLEY AND TIMING THIS BACK EDGE THROUGH THE SOUTH HALF OF THE CWA THIS MORNING. WILL USE 925 MB 70 PERCENT RH LINE AS A GUIDE. WILL HAVE TO CONTEND WITH MID LEVEL CLOUD DECK STREAMING NORTHWARD LATER THIS MORNING...AS WEAK UPPER WAVE OVER KANSAS/MISSOURI MOVES INTO THE LOWER GREAT LAKES. LOOKS LIKE THE AC DECK WILL ARRIVE SOMETIME AFTER 15Z...SO WILL JUST WORD ZONES AS MOSTLY CLOUDY...WITH ONLY BRIEF WINDOW OF SOME SUNSHINE LATER THIS MORNING. ETA/GFS APPEAR TO HAVE A GOOD HANDLE ON UPPER WAVE CURRENTLY OVER SOUTH DAKOTA...WHICH IS FCST TO SWEEP THROUGH THE LOWER GREAT LAKES LATE TONIGHT. MODELS SHOW GOOD OMEGA FIELD WITH THIS WAVE...WITH A 6 HOUR SHOT OF GOOD 1000-500 DPVA. MODELS EVEN SHOW A WEDGE OF POTENTIAL INSTABILITY OVER DTW AS 500 MB TEMPERATURES COOL TO -26C. WOULD LIKE TO SEE BETTER JET POSITION THOUGH...AS RIGHT REAR QUADRANT DROPS INTO OHIO VALLEY. WILL ADJUST POPS TO 60 PERCENT FAR SOUTH WITH AROUND AN INCH ACCUMULATION...THEN CHANCE POPS TO PTK AND FNT...MBS SOUNDINGS MAINTAIN A DRY WEDGE BETWEEN 5K AND 10K FEET AS WAVE TRACKS EAST...VERY WEAK ADIABATIC OMEGA ON 295K SFC NORTH OF FNT WITH CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 30 AND 50 MB. && .LONG TERM...SATURDAY THROUGH THURSDAY VERY COMPLICATED FLOW STRUCTURE HAS SET UP ACROSS THE EASTERN PACIFIC AND WESTERN NORTH AMERICA. THE EVOLUTION OF THESE FEATURES WILL ULTIMATELY HAVE AN IMPACT ON THE EASTERN CONUS AS THE CURRENT SPLIT FLOW CONFIGURATION ACROSS THE WEST BEGINS TO BREAK DOWN THROUGH NEXT WEEK. NUMERICAL SUITE HAVING SOME DIFFICULTY DEPICTING THE FEATURES OFF THE WEST COAST. THE GFS/WRFXX OFFER THE BEST DEPICTION WITH THE STRONG SHORTWAVE DIGGING SOUTH OUT OF BRITISH COLUMBIA, WHICH WILL BE THE MAJOR PLAYER WITH THE RE-ESTABLISHMENT OF THE LONG WAVE TROUGH ACROSS THE WEST OVER THE WEEKEND. STILL DON'T HAVE A GREAT DEAL OF CONFIDENCE ON THE OVERALL EVOLUTION OF THE WESTERN TROUGH AND THE SHORTWAVES THAT SHED EAST ACROSS THE CONUS IN RESPONSE TO THE INTERACTION WITH THE SUB-TROPICAL JET, GIVEN THE COMPLEX INTERACTIONS TAKING PLACE OUT THERE RIGHT NOW. UNTIL THE 18Z CYCLE EVEN THE GFS WAS FAR TOO UNDERAMPLIFIED THE BROAD LONGWAVE RIDGE WILL REMAIN IN PLACE ACROSS THE EASTERN CONUS THROUGH MUCH OF NEXT WEEK. BAROCLINICITY WILL CONTINUE TO BE QUITE HIGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGION THROUGH THE WEAK. THE THERMAL GRADIENT WILL WASH NORTH THROUGH THE FORECAST AREA ON SUNDAY AS HEIGHTS ALOFT BUILD IN ADVANCE OF AN EJECTING SHORTWAVE PROGGED TO MOVE THROUGH ONTARIO ON MONDAY. THE LOW LEVEL FRONT IS PROJECTED TO SLOSH BACK AND FORTH THROUGH THE REGION FOR MUCH OF THE WEEK. THIS WILL KEEP CONDITIONS SOMEWHAT UNSETTLED ALL WEEK LONG. HOWEVER, IT CERTAINLY WILL NOT FEEL LIKE EARLY JANUARY AS HIGHS SHOULD CLIMB WELL INTO THE 40S EARLY TO MID WEEK- BUT PLENTY OF WET WEATHER TO GO ALONG WITH IT. EVENTUALLY, HEIGHT FALLS ACROSS CENTRAL CANADA WILL BECOME ESTABLISHED ACROSS THE NORTHERN CONUS TRANSLATING THE WESTERN US TROUGH EASTWARD- THUS RETURNING THE FORECAST AREA BACK TO MORE SEASONABLE CONDITIONS BY WEEK'S END. && .AVIATION...ISSUED AT 1155 PM EST THURSDAY STRATUS DECK IS SLOWLY ADVANCING ACROSS THE FORECAST AREA... WITH TAF SITES ALREADY UNDER VFR CIGS. SOME CONVERGENCE OFF LAKE MICHIGAN IS PRODUCING SOME FLURRIES ACROSS SOUTHERN MICHIGAN. THE LAKE HAS ALSO APPEARED TO RAISE INVERSIONS A BIT. CEILINGS HAVE ACTUALLY RISEN TO AROUND 4K FT OVER MOST OF SE MICHIGAN. HOWEVER... MVFR CIGS ARE QUITE WIDESPREAD ACROSS INDIANA AND ILLINOIS. THEY ARE ALSO BEGINNING TO LOWER OVER SW MI AS INVERSION HEIGHTS FALL. AS THE BOUNDARY LAYER FLOW BACKS SOUTHWESTERLY LATE TONIGHT... EXPECT SOME OF THESE LOWER CLOUDS WILL LIFT NORTH. SOME DRYER LOW LEVEL AIR... APPARENT OVER SOUTHERN/CENTRAL MISSOURI WILL LIFT INTO SOUTHERN MICHIGAN LATE FRI MORNING. THIS COMBINED WITH ANTICYCLONIC LOW LEVEL FLOW AND LOWERING INVERSIONS SHOULD SCOUR OUT THE LOW CLOUDS BY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ GSS/MANN mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1155 PM EST THU JAN 6 2005 .AVIATION... STRATUS DECK IS SLOWLY ADVANCING ACROSS THE FORECAST AREA... WITH TAF SITES ALREADY UNDER VFR CIGS. SOME CONVERGENCE OFF LAKE MICHIGAN IS PRODUCING SOME FLURRIES ACROSS SOUTHERN MICHIGAN. THE LAKE HAS ALSO APPEARED TO RAISE INVERSIONS A BIT. CEILINGS HAVE ACTUALLY RISEN TO AROUND 4K FT OVER MOST OF SE MICHIGAN. HOWEVER... MVFR CIGS ARE QUITE WIDESPREAD ACROSS INDIANA AND ILLINOIS. THEY ARE ALSO BEGINNING TO LOWER OVER SW MI AS INVERSION HEIGHTS FALL. AS THE BOUNDARY LAYER FLOW BACKS SOUTHWESTERLY LATE TONIGHT... EXPECT SOME OF THESE LOWER CLOUDS WILL LIFT NORTH. SOME DRYER LOW LEVEL AIR... APPARENT OVER SOUTHERN/CENTRAL MISSOURI WILL LIFT INTO SOUTHERN MICHIGAN LATE FRI MORNING. THIS COMBINED WITH ANTICYCLONIC LOW LEVEL FLOW AND LOWERING INVERSIONS SHOULD SCOUR OUT THE LOW CLOUDS BY AFTERNOON. && .UPDATE...ISSUED AT 936 PM. SOME SURFACE RIDGING NUDGED INTO SE MICHIGAN THIS EVENING AND ALLOWED SKIES TO CLEAR IN MANY LOCATIONS. MEANWHILE... SURFACE HIGH PRESSURE CURRENTLY OVER THE MID MISSISSIPPI VALLEY WILL SETTLE INTO THE OHIO VALLEY OVERNIGHT. THIS WILL GRADUALLY BRING BOUNDARY LAYER WINDS AROUND TO THE SOUTHWEST ACROSS THE SOUTHERN GREAT LAKES BY DAYBREAK. STRONG MID LEVEL SUBSIDENCE ALREADY WORKING INTO LOWER MICHIGAN WILL ACT TO STRENGTHEN THE LOW LEVEL INVERSION... WHICH WILL CONTINUE TO ALLOW THE STRATUS ACROSS IL/IN/WESTERN LOWER MI TO EXPAND INTO SE MICHIGAN. THE 00Z KILX SOUNDING WAS A BIT COLDER IN THE BOUNDARY LAYER THAN SUGGESTED BY MODEL SOLUTIONS. SUSPECT THIS COLDER AIRMASS WILL HELP KEEP INVERSION HEIGHTS UP A BIT HIGHER OVER LAKE MICHIGAN THAN DEPICTED BY EITHER RUC OR ETA MODEL SOUNDINGS. INSTABILITY SHOULD BE ENOUGH TO PROVIDE A FEW FLURRIES OFF THE LAKE. THE LATEST GRR RADAR SUPPORTS THIS. SO WILL EXTEND SCATTERED FLURRIES INTO THE OVERNIGHT. WITH THE BRIEF CLEARING EXPERIENCED THIS EVENING... TEMPERATURES ACROSS MOST OF SE MICHIGAN FELL TO THE CURRENT FORECASTED LOWS. THE TEMPS SHOULD LEVEL OFF SINCE CLOUDS ARE ALREADY MOVING BACK INTO THE REGION. SO WILL JUST LOWER OVERNIGHT MIN TEMPS A COUPLE DEGREES. && .SHORT TERM...THROUGH FRIDAY (ISSUED AT 405 PM) SURFACE LOW RESPONSIBLE FOR THE WINTER STORM THIS MORNING IS NOW WELL OFF TO OUR EAST AT 29.60 INCHES OVER LAKE SUPERIOR. THIS LOW WILL CONTINUE TO PULL OFF TO OUR EAST THIS EVENING. A SURFACE TROUGH CURRENTLY EXTENDS FROM THIS LOW BACK ACROSS CENTRAL LOWER MICHIGAN. AN AREA OF CONVERGENCE AROUND THIS TROUGH HAS BEEN RESPONSIBLE FOR SNOW SHOWERS THROUGH THE AFTERNOON HOURS...THIS ACTIVITY HAS BEEN CONFINED MOSTLY TO THE GENESEE AND SAGINAW VALLEY THIS AFTERNOON BUT HAS NOW SPREAD SOUTHWARD DOWN TO M59. A FEW FLURRIES ARE POSSIBLE FOR A COUPLE OF HOURS THIS EVENING SOUTH OF M59. THE TROUGH ACROSS THE SAGINAW VALLEY WILL GET WASHED OUT EARLY THIS EVENING AS THE LOW PULLS OFF TO THE EAST AND ANTICYLONIC FLOW FROM HIGH PRESSURE APPROACHING FROM OUR SOUTHWEST BEGINS TO TAKE OVER. AS THIS HAPPENS...PRECIPITATION WILL COME TO AN END AS A BROAD SURFACE RIDGE WORKS IN ACROSS THE FORECAST AREA OVERNIGHT. WINDS WILL BACK TO THE SOUTHWEST BY MORNING BRINGING IN DRIER AIR. BIGGEST CHALLENGE WAS CLOUD COVER AND ITS IMPACT ON MAX AND MIN TEMPS. ETA IS MUCH MORE PESSIMISTIC WITH CLOUD COVER THROUGH FRIDAY...SUGGESTING LOW CLOUDS TO REMAINED TRAPPED UNDER INVERSION. GFS...ON THE OTHER HAND...BEGINS TO SCATTER CLOUDS OUT TOWARD FRIDAY MORNING. THE THINKING IS CLOUDS WILL HANG AROUND FOR THE MOST PART BUT THERE SHOULD BE ENOUGH HOLES THROUGH THE DAY ON FRIDAY TO GO WITH PARTLY SUNNY...UNTIL THEN WE WILL STAY CLOUDY OVERNIGHT. GUIDANCE NUMBERS LOOK REASONABLE BASED ON THESE ANTICIPATIONS...WENT CLOSER TO THE MAV GUIDANCE. && .LONG TERM... THE PATTERN APPEARS TO BE RELATIVELY QUIET THROUGH THE WEEKEND...AT LEAST COMPARED TO THE LAST FEW DAYS AND THE COMING WEEK. THERE IS A CAVIOT TO THIS UNFORTUNATELY. ETA...AND TO A DEGREE GFS HAS BECOME A BIT MORE AMPLIFIED WITH THE UPPER DISTURBANCE THAT RACES OUT OF THE MIDDLE OF THE CONUS FRIDAY INTO SATURDAY. THIS SYSTEM RESULTS FROM THE PHASING OF THE UPPER LOW OVER THE DAKOTAS WITH A VORTICITY CENTER CURRENTLY ROTATING THROUGH NEVADA. A BULK OF THE PRECIPITATION WITH THIS SYSTEM IS STILL FORECAST TO REMAIN WELL SOUTH OF THE CWA AS THE FLOW REMAINS BASICALLY ZONAL AND KEEPS THIS SYSTEM PROGRESSIVE. THAT SAID...12Z ETA OUTPUTS BETTER THAN A 1/4 INCH OF QPF LATE FRIDAY NIGHT INTO SATURDAY MORNING ACROSS THE SOUTHERN CWA. DON/T REALLY BUY THIS AMOUNT...BUT GFS ALSO PUTS SOME LIGHT SNOW INTO AREA DURING THIS TIMEFRAME (SUPPORTED BY CMC AND WRF AS WELL). WILL ADD A CHANCE OF LIGHT SNOW ACROSS SOUTHERN CWA DUE TO THIS CONSISTENCY IN MODELS NEXT WEEK WILL BE A DIFFICULT CHORE IN THE COMING DAYS. THE UPPER PATTERN TRENDS FROM THE BASICALLY ZONAL FLOW ON THE BASE OF LARGE NORTH AMERICAN TROF...TO SHARP SOUTHWEST FLOW IN ADVANCE OF STRONGLY AMPLIFYING WESTERN CONUS TROF DURING THE MIDDLE OF NEXT WEEK. AFTER THE SATURDAY WAVE RIPPLES THROUGH...ANOTHER RACES THROUGH LATE SUNDAY INTO MONDAY...BRINGING ANOTHER CHANCE OF -RA/-SN. THE ASSOCIATED FRONT THEN DROPS SOUTH OF THE AREA MONDAY NIGHT...ONLY TO RETURN ON NORTH IN INCREASINGLY SOUTHWEST UPPER FLOW TUESDAY INTO WEDNESDAY. WILL READJUST THE PLACEMENT/TIMING OF PRECIPITATION SOMEWHAT DURING THIS TIMEFRAME...BUT OVERALL FEEL TO THE FORECAST REMAINS THE SAME WITH PERIODIC CHANCE -RA/-SN SUNDAY NIGHT INTO TUESDAY. THEREAFTER...WE ENTER A PERIOD WITH A BETTER CHANCE OF SIGNIFICANT PRECIPITATION AS SUBTROPICAL/GULF MOISTURE SURGE NORTH/NORTHEAST ON THE LEADING EDGE OF DIGGING WESTERN TROF. GFS OUTPUTS QUITE A LOT OF RAIN FROM LATE TUESDAY THROUGH WEDNESDAY...AND WILL PIN THIS TIME AS THE BEST CHANCE OF RAIN...AS OPPOSED TO LIGHT SHOWERS ETC. BY THE END OF THIS FORECAST PERIOD...ARCTIC AIR RETURNS TO THE LAKES REGION. THIS TRANSITION IS FORECAST TO OCCUR IN ONE FASHION OR ANOTHER BY A HOST OF MODELS. THE GENERAL SCENARIO BEING A STRONG ARCTIC STORM CROSSING FROM SIBERIA OVER ALASKA. THIS SYSTEM KICKS AN UPPER LOW THAT IS IN THE PROCESS OF CUTTING OFF NEAR THE PACIFIC NORTHWEST ATTM ON INTO THE CENTRAL CONUS...WITH THE ARCTIC SYSTEM/AIRMASS THEN CHASING RAPIDLY IN BEHIND IT. GFS FOCUSES MUCH MORE ON THE NORTHERN SYSTEM & BASICALLY BRINGS THE ARCTIC FRONT THROUGH "UNEVENTFUL"...ASIDE FROM THE STEADY STREAM OF MOISTURE/RAIN BEFOREHAND. 12Z CMC AND 00Z ECMWF KEEP THE PACIFIC NORTHWEST SHORTWAVE INTACT AND RIDE IT INTO THE AREA ALONG THE ARCTIC FRONT...LEADING TO A BETTER CHANCE OF A SIGNIFICANT STORM TOWARD THE END OF THE FCST. NO CONFIDENCE IN EITHER SPECIFIC SOLUTION AT THIS STAGE IN THE GAME...BUT GIVEN THE STRONG OVERALL CONSENSUS ON THE UPPER PATTERN TRANSITION BY MODELS...AT LEAST FOR A DAY 6/7 FORECAST WILL TREND FORECAST MUCH COLDER AT THE TAIL END OF THE FORECAST...AND TRANSITION RAIN CHANCE TO LIGHT SNOW SHOWERS CHCS. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ GURNEY/SHULER/CONSIDINE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 345 AM CST FRI JAN 7 2005 .SYNOPSIS... A WEAK SURFACE LOW(1013MB) IN WRN GULF WILL TRACK NEWD AS IT LIFTS A STATIONARY FRONT ALONG THE COAST INLAND. LOW SHOULD TRACK ACROSS CENTRAL LA INTO SRN MS BETWEEN KHEZ AND KMCB BY EARLY AFTERNOON. EXPECT THE LOW TO TRACK BETWEN KMEI AND KCBM DURING THE EVENING TAKING THE REMAINING RAINFALL E OF THE CWFA SOMETIME AFTER MIDNIGHT TONIGHT. THEN A HIGH PRESSURE RIDGE BUILDS FROM THE OH VALLEY TO THE TX COAST SATURDAY EASING SEWD TO THE CAROLINA COAST BY MONDAY UNDER NEARLY ZONAL FLOW ALOFT ACROSS THE SRN HALF OF THE CONUS. NEXT WEEK...A POLAR VORTEX ROTATES FROM CENTRAL CANADA TOWARD HUDSON BAY CARVING OUT A DEEP UPPER TROUGH AXIS OVER CENTRAL NA BY WEDNESDAY. THIS TROUGH MOVES THROUGH ERN CONUS BY FRIDAY BRINGING A CHANGE BACK TO WINTER COLD FOR THE REGION. && .SHORT TERM... ISENTROPIC LIFT ALREADY UNDERWAY OVER MAINLY N HALF OF MS WHERE SOME MIXED PRECIP POSSIBLE FOR A FEW HOURS THIS MORNING. GFS/RUC HANDLING THE INITIAL ZONE OF RAINFALL BEST AND LOOK FOR MORE RAIN TO BREAK OUT OVER WRN 2/3 OF OUR CWFA BY LATE MORNING AS GULF LOW MOVES ONSHORE. RAINS SHOULD CONTINUE EXPANDING THIS AFTERNOON WITH SOME DECENT DOWNPOURS AS PWATS RISE CLOSE TO 1.5 INCHES. BEST WARMING THIS AFTERNOON AND INSTABILITY SHOULD DEVELOP OVER SERN MS. EVEN SO...7-5H LAPSE RATES 5.5-6C WITH SHOWALTERS 0 TO -1 BY EVENING AS BEST UVV CROSSES NWRN HALF OF FA WHERE TOTALS REACH A MORE IMPRESSIVE 51. INCREASING UPPER DIVERGENCE SHOULD PERSIST FROM 18Z-06Z BEFORE SYSTEM PULLS E WHILE LOW LEVEL CONVERGENCE FIELDS NEVER DO GET VERY IMPRESSIVE. ALL IN ALL...LOOK FOR WIDESPREAD 1 INCH RAINS AND LOCALLY 2 INCHES BEFORE ENDING PRIOR TO SUNRISE SATURDAY. DRYING OUT PROCESS AND CLEARING SATURDAY MORNING WILL SET UP A MOSTLY CLEAR SATURDAY NIGHT WITH LIGHT N WINDS. LOOK FOR A RETURN TO SLY FLOW ON SUNDAY WITH MORE HIGH LEVEL MOISTURE STREAMING BACK INTO THE REGION AS WARMING TREND A GOOD BET GOING INTO THE MEDIUM RANGE. .LONG TERM... MILDER AIRMASS THAT STARTS SUNDAY AFTERNOON SHOULD HOLD THROUGH THE MIDDLE OF NEXT WEEK WITH HIGHS FREQUENTLY TOPPING 70F ONCE AGAIN MONDAY THROUGH WEDNESDAY. WIND FIELDS INTENSIFY WITH A POTENTIAL OF STRONG/SEVERE THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY AS A STRONG COLD FRONT CROSSES THE REGION THURSDAY. WILL NEED TO CONTINUE MONITORING MODEL TRENDS FOR THIS SYSTEM AS THE POLAR VORTEX MOVING S IN CANADA JERKS A PIECE OF SIBERIAN AIR INTO NA. THIS AIRMASS DIVES TOWARD THE NRN CONUS NEXT FRIDAY SETTING US UP FOR ANOTHER COLD HOLIDAY WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 58 51 58 46 / 100 100 20 10 MERIDIAN 62 52 64 44 / 90 100 30 10 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 10/40 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 945 AM EST FRI JAN 7 2005 .DISCUSSION... A FEW LIGHT SHOWERS/SPRINKLES MOVING NORTH THROUGH INTERIOR SECTIONS AGAIN THIS MORNING WITH MOIST LOW LEVELS AND WEAK WAA...ALSO BAND OF SHOWERS MOVING OVER THE GULF STREAM WATERS. LINGERING MORNING FOG AND LIGHT RAIN SHOULD CONTINUE A GRADUAL DIMINISHING TREND THROUGH MIDDAY. LOW CLOUDS SHOULD SCATTER OUT AS WELL AND SOME CIRRUS WILL STREAM OVERHEAD...WITH SKIES AVERAGING OUT PARTLY CLOUDY. MAX TEMPS WILL AGAIN CLIMB ABOVE EARLY JAN NORMS...REACHING AOA 80 MOST EC FL LOCATIONS. ONLY MINOR EDITS TO GRIDS THIS MORNING...TEXT ZONES STILL ON TRACK...HANDLING LIGHT RAIN/FOG IN SHORT TERM FORECASTS. && .MARINE...LATEST RUC/MSAS SURFACE ANALYZES PLACE RIDGE AXIS OVER NORTH PART OF OUR CWA RESULTING IN LIGHT/MODERATE SOUTH TO SOUTHWEST WINDS OVER THE COASTAL WATERS. BUOY 009 WAS RECORDING SOUTHWEST WINDS AT 6 TO 8 KNOTS AND 3 FOOT SEAS WITH AN 11 SECOND PERIOD. RADAR WAS DETECTING SHOWERS ALONG THE EDGE OF THE GULF STREAM WHICH MATCHES THE MARINE GRIDS WEATHER VERY NICELY. WINDS HAVE BEEN OUT OF THE SOUTH TO SOUTHWEST THE PAST 24 HOURS SO WILL VEER WINDS TO MORE OF A SOUTHERLY DIRECTION FOR THE AFTERNOON UPDATE. WIND SPEEDS AND SEAS LOOK GOOD. && .MLB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...GLITTO LONG TERM...WIMMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1057 AM EST FRI JAN 7 2005 .DISCUSSION... MAIN CONCERN WITH THIS UPDATE IS THE SNOW POTENTIAL FOR SOUTHEAST U.P. THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A SHORTWAVE MOVING THROUGH THE NORTHERN PLAINS EXTENDING NORTHEAST INTO WESTERN ONTARIO. EMBEDDED IN THIS SHORTWAVE IS A WEAK LOW OVER EASTERN SOUTH DAKOTA. 270K ISENTROPIC ANALYSIS SHOWING WEAK ASCENT AHEAD OF THE FRONT PRODUCING LOW CLOUDS TO THE NORTH OF THE FORECAST AREA. SURFACE ANALYSIS INDICATES A LOW OVER WEST CENTRAL ONTARIO WITH A COLD FRONT STRETCHING SOUTHWEST ACROSS NORTHERN MINNESOTA AND SOUTHERN NORTH DAKOTA. LOW CLOUDS WILL STAY TO THE NORTH OF THE COLD FRONT. A SMALL PORTION OF THE SHORTWAVE WILL SHIFT OVER THE FORECAST AREA THIS AFTERNOON AND SHOULD PRODUCE MORE CLOUD COVER. THE ANOTHER PART OF THE SHORTWAVE WILL REMAIN TO THE SOUTH OF THE FORECAST AREA AND WILL BE OVER SOUTHERN WISCONSIN AND LOWER MICHIGAN. ANOTHER SECTION OF THE SHORTWAVE WILL STAY OVER NORTHERN MINNESOTA AND WESTERN ONTARIO. THE COLD FRONT WILL EDGE INTO WESTERN LAKE SUPERIOR. THE AIR MASS WILL BE MOST STABLE OVER THE THE IRON MOUNTAIN/IRON RIVER AREAS THIS AFTERNOON. SURFACE-900MB RH WILL BE AROUND 90 PERCENT. WINDS WILL REMAIN OUT OF TH SOUTHWEST...SO DO NOT THINK ANY PRECIPITATION WILL DEVELOP. ELSEWHERE THE AIR MASS WILL BE TOO DRY TO DEVELOP SIGNIFICANT SNOW. A FAIR AMOUNT OF CLOUD COVER STILL POSSIBLE. THE GOING FORECAST LOOKS GOOD. THE WORDING IN THE DELTA-SOUTHERN SCHOOLCRAFT COUNTIES FORECAST WILL NEED TWEAKING. OTHERWISE NO CHANGES WILL BE NEEDED. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1051 AM EST FRI JAN 7 2005 .UPDATE... UPDATED ZONES TO BLANKET ENTIRE AREA WITH A MENTION OF SCATTERED FLURRIES. NEARLY ALL OBS OVER SOUTHWEST MICHIGAN REPORTING LIGHT SNOW WITH VISIBILITIES B/W 1 AND 3 MILES. NO REPORTS AS OF YET OF ANY FLURRIES OVER SOUTHEAST MICHIGAN WITH THE EXCEPTION OF BAD AXE WHERE A FEW FLURRIES HAVE BEEN OCCURRING THERE THIS MORNING. CURRENT RUC ANALYSIS SHOWS A BIT OF A VORT MAX THROUGH THIS AREA WITH A SLIGHT BEND IN THE SURFACE PRESSURE ON THE NORTHWESTERN FLANK OF SURFACE HIGH NOW MOVING THROUGH OHIO. MOISTURE IS VERY SHALLOW (DTX RADAR OVERSHOOTING ALL OF THIS ACTIVITY)...SO DON'T ANTICIPATE ANYTHING MORE THAN FLURRIES THIS AFTERNOON. ALSO DECIDED TO GO MOSTLY CLOUDY FOR THE REMAINDER OF THE DAY. LOWER CLOUDS WILL HAVE A BETTER TIME HOLDING ON AS MID CLOUDS REMAIN ABOVE...SO EVEN AS LOW CLOUDS DO SLOWLY SCATTER OUT...THERE WILL BE ENOUGH MID LEVEL CLOUDS TO WARRANT MOSTLY CLOUDY TODAY. TEMPS LOOK GOOD...NO CHANGES THERE. $$ .SHORT TERM...ISSUED AT 310 AM EST. FLURRIES DIMINISHING QUICKLY WEST OF MBS AND FNT AS 850 TEMPERATURES CONTINUE TO WARM AND INVERSION HEIGHTS FALL TO LESS THAN 3K FT OVER LAKE MICHIGAN...SO WILL NOT MENTION ANY FLURRIES EARLY THIS MORNING IN ZONE PACKAGE. LARGE AREA OF LOW CLOUDS SNEAKING IN UNDER INVERSION THOUGH AND FILLING IN THE FEW HOLES THAT DEVELOPED OVERNIGHT. LOOKS LIKE 40KM RUC HAS A GOOD HANDLE ON SOUTHERN EXTENT OF LOW CLOUDS OVER THE OHIO VALLEY AND TIMING THIS BACK EDGE THROUGH THE SOUTH HALF OF THE CWA THIS MORNING. WILL USE 925 MB 70 PERCENT RH LINE AS A GUIDE. WILL HAVE TO CONTEND WITH MID LEVEL CLOUD DECK STREAMING NORTHWARD LATER THIS MORNING...AS WEAK UPPER WAVE OVER KANSAS/MISSOURI MOVES INTO THE LOWER GREAT LAKES. LOOKS LIKE THE AC DECK WILL ARRIVE SOMETIME AFTER 15Z...SO WILL JUST WORD ZONES AS MOSTLY CLOUDY...WITH ONLY BRIEF WINDOW OF SOME SUNSHINE LATER THIS MORNING. ETA/GFS APPEAR TO HAVE A GOOD HANDLE ON UPPER WAVE CURRENTLY OVER SOUTH DAKOTA...WHICH IS FCST TO SWEEP THROUGH THE LOWER GREAT LAKES LATE TONIGHT. MODELS SHOW GOOD OMEGA FIELD WITH THIS WAVE...WITH A 6 HOUR SHOT OF GOOD 1000-500 DPVA. MODELS EVEN SHOW A WEDGE OF POTENTIAL INSTABILITY OVER DTW AS 500 MB TEMPERATURES COOL TO -26C. WOULD LIKE TO SEE BETTER JET POSITION THOUGH...AS RIGHT REAR QUADRANT DROPS INTO OHIO VALLEY. WILL ADJUST POPS TO 60 PERCENT FAR SOUTH WITH AROUND AN INCH ACCUMULATION...THEN CHANCE POPS TO PTK AND FNT...MBS SOUNDINGS MAINTAIN A DRY WEDGE BETWEEN 5K AND 10K FEET AS WAVE TRACKS EAST...VERY WEAK ADIABATIC OMEGA ON 295K SFC NORTH OF FNT WITH CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 30 AND 50 MB. && .LONG TERM...SATURDAY THROUGH THURSDAY VERY COMPLICATED FLOW STRUCTURE HAS SET UP ACROSS THE EASTERN PACIFIC AND WESTERN NORTH AMERICA. THE EVOLUTION OF THESE FEATURES WILL ULTIMATELY HAVE AN IMPACT ON THE EASTERN CONUS AS THE CURRENT SPLIT FLOW CONFIGURATION ACROSS THE WEST BEGINS TO BREAK DOWN THROUGH NEXT WEEK. NUMERICAL SUITE HAVING SOME DIFFICULTY DEPICTING THE FEATURES OFF THE WEST COAST. THE GFS/WRFXX OFFER THE BEST DEPICTION WITH THE STRONG SHORTWAVE DIGGING SOUTH OUT OF BRITISH COLUMBIA, WHICH WILL BE THE MAJOR PLAYER WITH THE RE-ESTABLISHMENT OF THE LONG WAVE TROUGH ACROSS THE WEST OVER THE WEEKEND. STILL DON'T HAVE A GREAT DEAL OF CONFIDENCE ON THE OVERALL EVOLUTION OF THE WESTERN TROUGH AND THE SHORTWAVES THAT SHED EAST ACROSS THE CONUS IN RESPONSE TO THE INTERACTION WITH THE SUB-TROPICAL JET, GIVEN THE COMPLEX INTERACTIONS TAKING PLACE OUT THERE RIGHT NOW. UNTIL THE 18Z CYCLE EVEN THE GFS WAS FAR TOO UNDERAMPLIFIED THE BROAD LONGWAVE RIDGE WILL REMAIN IN PLACE ACROSS THE EASTERN CONUS THROUGH MUCH OF NEXT WEEK. BAROCLINICITY WILL CONTINUE TO BE QUITE HIGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGION THROUGH THE WEAK. THE THERMAL GRADIENT WILL WASH NORTH THROUGH THE FORECAST AREA ON SUNDAY AS HEIGHTS ALOFT BUILD IN ADVANCE OF AN EJECTING SHORTWAVE PROGGED TO MOVE THROUGH ONTARIO ON MONDAY. THE LOW LEVEL FRONT IS PROJECTED TO SLOSH BACK AND FORTH THROUGH THE REGION FOR MUCH OF THE WEEK. THIS WILL KEEP CONDITIONS SOMEWHAT UNSETTLED ALL WEEK LONG. HOWEVER, IT CERTAINLY WILL NOT FEEL LIKE EARLY JANUARY AS HIGHS SHOULD CLIMB WELL INTO THE 40S EARLY TO MID WEEK- BUT PLENTY OF WET WEATHER TO GO ALONG WITH IT. EVENTUALLY, HEIGHT FALLS ACROSS CENTRAL CANADA WILL BECOME ESTABLISHED ACROSS THE NORTHERN CONUS TRANSLATING THE WESTERN US TROUGH EASTWARD- THUS RETURNING THE FORECAST AREA BACK TO MORE SEASONABLE CONDITIONS BY WEEK'S END. && .AVIATION...ISSUED AT 1155 PM EST THURSDAY STRATUS DECK IS SLOWLY ADVANCING ACROSS THE FORECAST AREA... WITH TAF SITES ALREADY UNDER VFR CIGS. SOME CONVERGENCE OFF LAKE MICHIGAN IS PRODUCING SOME FLURRIES ACROSS SOUTHERN MICHIGAN. THE LAKE HAS ALSO APPEARED TO RAISE INVERSIONS A BIT. CEILINGS HAVE ACTUALLY RISEN TO AROUND 4K FT OVER MOST OF SE MICHIGAN. HOWEVER... MVFR CIGS ARE QUITE WIDESPREAD ACROSS INDIANA AND ILLINOIS. THEY ARE ALSO BEGINNING TO LOWER OVER SW MI AS INVERSION HEIGHTS FALL. AS THE BOUNDARY LAYER FLOW BACKS SOUTHWESTERLY LATE TONIGHT... EXPECT SOME OF THESE LOWER CLOUDS WILL LIFT NORTH. SOME DRYER LOW LEVEL AIR... APPARENT OVER SOUTHERN/CENTRAL MISSOURI WILL LIFT INTO SOUTHERN MICHIGAN LATE FRI MORNING. THIS COMBINED WITH ANTICYCLONIC LOW LEVEL FLOW AND LOWERING INVERSIONS SHOULD SCOUR OUT THE LOW CLOUDS BY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ GSS/MANN/SHULER mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1050 AM EST FRI JAN 7 2005 .SHORT TERM (REST OF TODAY)... RADAR TRENDS CONFIRM THAT THE MESOETA AND RUC HAVE THE CORRECT SOLUTION OF BRINGING THE SHRA EAST OF THE MTNS LATE THIS AFTERNOON/THIS EVENING. WILL TRIM BACK POPS TO REFLECT THAT THE HIGHER TERRAIN WILL SEE THE BEST CHANCE OF SHRA THIS AFTERNOON...HOLD OFF EAST OF THE MTNS UNTIL LATE THIS AFTERNOON WITH A LOW CHC. TEMPERATURES SHOULD BE ABLE TO REACH THE CURRENT FORECAST LEVELS THIS AFTERNOON THANKS TO THE DELAYED ONSET OF THE PRECIPITATION. THE ONLY LIMITING FACTORS FOR TEMPS IS THE BKN TO OVC SKY EXPECTED TO CONTINUE THROUGH THE DAYTIME. WILL REWORK T/DPTS BASED ON THE LATEST OBS. && .FIRE WEATHER... GIVEN THE LATEST MODEL GUIDANCE IN MIXING HEIGHTS AND PRECIP TIMING IN THE FIRST PERIOD I HAVE UPDATED THE FWF AND FIRE WX GRIDS. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 218 AM EST FRI JAN 7 2005 SHORT TERM (TODAY THROUGH SUNDAY)... SURFACE COLD FRONT CONTINUES TO WORK ITS WAY ACROSS THE CWFA...WITH DEWPOINTS FALLING BEHIND THE FEATURE. SOME THINNING OF THE GENERAL OVERCAST INTERACTING WITH WET GROUND AND HIGH RH TO PRODUCE FOG. FOR NOW...WILL MENTION JUST PATCHY DENSE FOG BUT WATCH CLOSELY FOR POTENTIAL DENSE FOG ADVISORY. WINDS MAY STAY UP JUST ENOUGH... HOWEVER...TO PRECLUDE SUCH MEASURES. SHORT RANGE MODELS IN GOOD AGREEMENT IN DEVELOPING UPGLIDE OVER THE OLD FRONT THIS MORNING IN THE WEST...AND ACROSS ALL OF THE FORECAST AREA BY LATE AFTERNOON. UPSTREAM RADAR COMPOSITE SHOWS CONVECTION BREAKING OUT IN STRONGEST UPGLIDE ACROSS MISSISSIPPI AND ALABAMA. BEST LIFT...AND MOISTURE...ACROSS THE WESTERN ZONES TIL EVENING... COINCIDENT WITH PASSAGE OF STRONG SHORTWAVE THAT SHOULD STAY WELL NORTH OF OUR REGION. WILL PLAN ON CHANCE POPS WEST THIS MORNING... SPREADING TOWARD INTERSTATE 77 CORRIDOR THROUGH AFTERNOON...WITH LIKELIES WEST. RAINFALL SHOULD GET HEAVIEST THIS EVENING...AS CWFA GETS BRIEFLY INTO RIGHT ENTRANCE REGION OF UPPER JET...AND AGAIN ACROSS TENNESSEE BORDER AREAS. CATEGORICAL MOUNTAINS TO LIKELY POPS FOOTHILLS AND PART OF THE PIEDMONT. HELD ON TO HIGH CHANCE SOUTHEAST ZONES OVERNIGHT. WAVE EXPECTED TO DEVELOP IN THE UPGLIDE REGIME AND PASS OVER THE CENTRAL APPALACHIANS EARLY SATURDAY...SHOULD DRAG A SECONDARY BOUNDARY OVER OUR REGION...PULLING BEST MOISTURE AND LIFT NORTH THROUGH THE SATURDAY MORNING PERIOD. CLEARING EXPECTED FROM THE WEST DURING AFTERNOON...THEN HIGH PRESSURE AT SURFACE AND RE- AMPLIFICATION OF UPPER RIDGE OVER THE SOUTHEAST POINTING TO PLEASANT AND WARM END OF THE WEEKEND. TEMPERATURES TRICKY TODAY; THICKNESSES CAME IN SLIGHTLY COOLER ON THIS RUN THAN ON PREVIOUS RUNS AND LOOKS LIKE CLOUD COVER MAY NOT BE THIN ENOUGH FOR MUCH HEATING. TRENDED TEMPERATURES 50S TO LOWER 60S WEST...BUT MAINTAINED MID 60S EAST AND SOUTHEAST WHERE ISENTROPIC UPGLIDE WILL BE WEAKEST AND LATEST TO OCCUR. 60S IN GENERAL FOR SATURDAY...WITH 60S NORTHWEST TO SOME LOWER 70S FOR SUNDAY. OVERNIGHT MINS 30S AND 40S...WITH SOME 50S SOUTH TONITE DUE CLOUD COVER AND RAIN SHOWERS. LONG TERM (SUNDAY NIGHT THROUGH THURSDAY)... THE SOUTHEAST REMAINS SOLIDLY IN A WARM SECTOR AIRMASS MONDAY THROUGH EARLY THURSDAY...WITH TEMPERATURES CONTINUING TO RUN WELL ABOVE NORMAL. PRECIPITATION CHANCES WILL STEADILY INCREASE FROM THE WEST WED INTO THU AS A SOUTHERLY FLOW FROM THE GULF INCREASES DEEP LAYER MOISTURE AHEAD OF AN APPROACHING COLD FRONT. NO CHANGES IN THE TIMING OF THE PRECIPITATION MID TO LATE WEEK ARE EXPECTED WITH THIS FORECAST PACKAGE. AVIATION... LOTS OF CIRRUS STREAMING OVER THE AREA AS SWLY FLOW ALOFT CONTINUES. EXPECT VFR CONDITIONS FOR MUCH OF THE OVERNIGHT HOURS AS LOW LEVELS REMAIN DRY. SFC FNT SLOW TO MOVE THRU THE AREA AS EVIDENCED BY SLOWER THAN EXPECTED WIND SHIFT AND DEW POINT DROP OFF. WITH THE WET GROUND AND LIGHT WIND OVERNIGHT...FOG STILL A POSSIBILITY EVEN WITH THE LOW LEVEL DRYING. HAVE MVFR TEMPO AROUND SUNRISE AT ALL SITES...EXCEPT PREVAILING MVFR AND TEMPO IFR AT THE MORE FOG PRONE KAND. ATMOS MOISTENS THRU A DEEP COLUMN ABOUT 00Z AS NEXT WAVE OF LOW PRESSURE MOVES TOWARD THE AREA. ETA SLOWER THAN GFS WITH PRECIP ENTERING THE AREA. GIVEN THE DIFFERENCES ONLY ADDED A VCSH AT KAND AND NOTHING ELSEWHERE. IF PRECIP SETS IN SOONER...MVFR AND POSSIBLY IFR CONDITIONS WILL DEVELOP BEFORE 06Z. WILL LET LATER SHIFTS SEE IF A TREND DEVELOPS BEFORE ADDING RESTRICTIONS. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM / FIRE WEATHER (UPDATE)...NED sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EST FRI JAN 7 2005 .DISCUSSION... BASICALLY...BENIGN WEATHER EXPECTED OVER THE NEXT FEW DAYS. MINOR CHANCES FOR SOME LIGHT PCPN WILL BE THE MAIN FCST ISSUE. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW FOR THE MOST PART WSW FLOW OVER THE CONUS BETWEEN TROF ALONG THE W COAST AND STRONG RIDGE JUST OFF THE SE COAST. THERE ARE SEVERAL NOTABLE SHORTWAVES IN THE FLOW THOUGH. ONE SHORTWAVE WAS MOVING E OF NEW ENGLAND...ANOTHER WAS OVER THE CNTRL PLAINS AND A THIRD WAS MOVING THRU CA INTO NV. AT THE SFC...COLD FRONT ASSOCIATED WITH SHORTWAVE OVER THE CNTRL PLAINS AND ONE IN CANADA EXTENDS THRU MN AND FAR NWRN IA. SOME FLURRIES/-SN HAVE BEEN NOTED ALONG AND JUST BEHIND FRONT...BUT NOT MUCH SHOWING UP ON RADARS. CLOSER TO HOME...LONG AXIS LIGHT LES WAS OCCURRING OVER WRN LAKE SUPERIOR IN SW FLOW...SOME OF WHICH WAS BRUSHING THE KEWEENAW N OF HOUGHTON. OTHERWISE...CLR/PARTLY CLOUDY SKIES PREVAIL OVER UPPER MI THIS AFTN. SHORTWAVE OVER THE PLAINS WILL PASS WELL S OF HERE TONIGHT AND WILL NOT BE A FACTOR FOR UPPER MI. SFC COLD FRONT WILL DROP INTO UPPER MI DURING THE NIGHT BEFORE STALLING OUT UNDER WSW FLOW ALOFT. UPSTREAM 12Z OBSERVED SOUNDING AT KINL SHOWED TYPICAL ARCTIC AIRMASS WITH SFC BASED INVERSION EXTENDING UP TO AROUND 875MB WHERE TEMP WAS -6C. BLO AT 900MB...TEMP WAS -14C (PLENTY COLD ENOUGH FOR SHALLOW CONVECTION OVER THE LAKE). COLUMN WAS NEARLY SATURATED UP TO 900MB BEFORE DWPT DEPRESSIONS INCREASED TO 9C AT 850MB. 12Z ETA SOUNDING FOR KINL LOOKED WELL INITIALIZED AND DOWNSTREAM FCST SOUNDINGS LOOK REASONABLE ACROSS LAKE SUPERIOR/UPPER MI. SFC COLD FRONT WILL SLIDE INTO NW FCST AREA LATE THIS EVENING WHICH WILL BRING LONG AXIS LES OVER WRN LAKE FIRMLY ONSHORE. DESPITE LONG AXIS FETCH...LES WILL REMAIN LIGHT DUE TO INVERSION REMAINING AROUND 3KFT AND RATHER PRONOUNCED DRIER AIR ABOVE INVERSION. NONETHELESS...MAY SEE AN INCH OR TWO SIMPLY DUE TO LONG FETCH AVBL. FRONT SLOWS DOWN OVERNIGHT AND MAY NOT EVER SLIP ONSHORE OVER THE ERN FCST AREA AS LAND BREEZE STRENGTHENS PER WSETA AND RUC13. WILL HOLD OFF ON BRINGING ANY LES ONSHORE THERE. STALLED OUT FRONT OVER LAKE SUPERIOR/NRN UPPER MI WILL BEGIN TO SHIFT BACK N LATER SAT. WILL CONFINE -SHSN/FLURRIES TO THE KEWEENAW AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE IN THE MORNING. IT MAY BE LATE IN THE DAY BEFORE FLURRIES END ON THE KEWEENAW AS WINDS BECOME LIGHT SE. SHOULD BE A FAIRLY NICE JAN DAY WITH TEMPS RISING INTO THE 20S AND A WEAK PRES GRADIENT RESULTING IN LITTLE WIND FOR MUCH OF THE DAY. A SHORTWAVE PASSES ACROSS THE UPPER MIDWEST LATE SAT AFTN/EVENING... BUT BEST ISENTROPIC LIFT (290K SFC) AND LOWERING OF CONDENSATION PRES DEFICITS OCCUR JUST NW AND N OF UPPER MI...SO NOT EXPECTING ANY PCPN SAT NIGHT. HOWEVER...WEAK LIFT OVER SHALLOW MOIST LAYER COULD RESULT IN SOME SPOTTY FZDZ OR FLURRIES WITH TEMP IN THE MOIST LAYER AROUND -10C. WILL LEAVE OUT FOR NOW SINCE IT'S A LOW PROBABILITY EVENT IN THE THIRD PERIOD. ANOTHER SHORTWAVE HEADS ACROSS THE NRN PLAINS AND INTO THE WRN GREAT LAKES SUN. GFS LOOKS TOO STRONG WITH SFC REFLECTION WHILE ETA TOO FAST AND PERHAPS A BIT TOO WEAK. UKMET/CANADIAN ARE VERY SIMILAR AND OFFER A GOOD COMPROMISE. IN ADDITION...THEY ARE ALSO QUITE SIMILAR TO 00Z ECMWF RUN. WILL BRING IN A CHC OF -SN SUN AFTN/SUN NIGHT WITH THIS FEATURE. PCPN TYPE SHOULD ONLY BE SNOW BASED ON 850MB TEMPS/1000-850MB THICKNESS... THOUGH IT WILL BE CLOSE ACROSS FAR SRN/SE SECTIONS. EXPECT SOME LES TO DEVELOP OFF LAKE SUPERIOR MON BEHIND SYSTEM AS 850MB TEMPS DROP TO AROUND -13C. TUE-FRI...STABLE PATTERN OF RECENT OVER NAMERICA BEGINS TO TRANSITION DURING THIS PERIOD AS PERSISTENT TROF ALONG W COAST BECOMES PROGRESSIVE. TROF AXIS SHOULD BE OVER CNTRL NAMERICA BY MID/LATE WEEK. CANADIAN/UKMET/ECMWF/GFS ALL AGREE ON THE LARGE SCALE PROGRESSION WITH DISAGREEMENT IN THE DETAILS OF SHORTWAVES. ON TUE WRN TROF WILL SHIFT E TO THE ROCKIES WITH STRENGTHENING SW FLOW/WAA DOWNSTREAM ACROSS PLAINS INTO GREAT LAKES. PCPN SHOULD BREAK OUT ACROSS THE WRN LAKES...BUT UKMET DOES OFFER STRONGER HIGH PRES RIDGING FROM QUEBEC/ONTARIO WWD...RESULTING IN A BETTER FEED OF ERLY LOW-LEVEL COLD/DRY AIR INTO UPPER MI WHICH WOULD DELAY ONSET TO AT LEAST TUE NIGHT. FOR NOW...WILL MAINTAIN GOING FCST OF LOW CHC POP OF -SN TUE AFTN UNTIL DRIER TREND BECOMES MORE CERTAIN. MOVING INTO WED...NRN/SRN STREAM SHORTWAVE INTERACTION/TIMING WILL BE AN ISSUE THAT WON'T BE CLEARED UP FOR A FEW DAYS. 00Z/06Z GFS ARE THE OUTLIERS BEING TOO QUICK MOVING ENTIRE TROF AND SFC FRONT EWD...BUT 06Z GFS IS HINTING AT A STRONGER SFC WAVE MOVING ALONG FRONT INTO GREAT LAKES WED NIGHT ASSOCIATED WITH SRN STREAM ENERGY...SUGGESTING A POSSIBLE TREND TOWARD A SLOWER SOLUTION. 12Z GFS HAS TRENDED SLOWER...BUT IS STILL ON THE FAST SIDE OF MODEL SOLUTIONS. 12Z/06JAN ECMWF HAD A RAPIDLY STRENGTHENING SFC LOW MOVING W OF UPPER MI TO HUDSON BAY. 00Z ECMWF BACKED OFF ON STRENGTH SOME...BUT JUST ARRIVED 12Z EC IS BACK ONTO THE PREVIOUS STRONG LOW MOVING JUST W OF UPPER MI WED EVENING. CANADIAN/UKMET ARE VERY SIMILAR WITH A SFC LOW MOVING OVER OR JUST W OF UPPER MI LATE WED. WILL THUS FAVOR AN ECWMF/CANADIAN/UKMET TYPE SOLUTION FOR THE MIDWEEK PERIOD. REMAINS TO BE SEEN IF SUFFICIENT NRN/SRN STREAM INTERACTION WILL OCCUR TO GENERATE A SIGNIFICANT STORM SYSTEM AS EC IS ADVERTISING. STRONG WAA TUE NIGHT INTO WED WILL LIKELY CHANGE PCPN TYPE TO A MIX AND POSSIBLY TO JUST RAIN GIVEN RECENT CONSISTENCY OF ECMWF AND EVEN GFS ON DEGREE OF WARMING IN ADDITION TO WARM CANADIAN/UKMET LOOK. WILL TRANSITION PCPN TYPE TO RAIN/SNOW ACROSS ALL OF FCST AREA TUE NIGHT/WED AND TO JUST RAIN OVER SE SECTIONS. MAY NEED TO CONSIDER SOME FZRA IN LATER FCSTS AS WELL. STRONG CAA AND ARCTIC AIR WILL FLOOD INTO THE GREAT LAKES BEHIND SYSTEM THU/FRI WITH EXTENSIVE LES DEVELOPING IN GENERAL NW LOW-LEVEL FLOW. GFS ENSEMBLE MEAN HAS 850MB TEMPS FALLING INTO THE MID -20S CELCIUS WITH OP ECMWF RUN SHOWING A SIMILAR SOLUTION BASED ON NEW 12Z RUN. THIS COULD BE THE COLDEST AIRMASS OF THE SEASON...AND TEMPS BY FRI WILL LIKELY STRUGGLE TO REACH 0F OVER INTERIOR SW SECTIONS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 330 PM EST FRI JAN 7 2005 .DISCUSSION...SURFACE HIGH PRESSURE CONTINUES TO PULL EAST THIS AFTERNOON TOWARD THE MID ATLANTIC COAST. WEAK TROUGH/COLD FRONT EXTENDING FROM WESTERN ONTARIO SOUTHWEST ACROSS MN/EASTERN SD/ EASTERN NE HAS BEEN SLOWLY WEAKENING AS IT HEADS TOWARD THE WESTERN GREAT LAKES. MEANWHILE ANOTHER SHORT WAVE TROUGH OVER THE SOUTHERN PLAINS STARTING TO TURN NORTHEAST...WITH WV IMAGERY INDICATING A WEAKER WAVE OVER SD/NE GETTING SHEARED OUT. GOOD DEAL OF CLOUD COVER REMAINS OVER MOST OF NORTHERN MI THIS AFTERNOON...WITH SOME SHALLOW LAKE INDUCED SNOW SHOWERS/FLURRIES OVER LAKE MICHIGAN. MAIN CONCERN TONIGHT DEALS WITH CLOUD COVER AND LINGER LAKE EFFECT...WITH ONE EYE ON SOUTHERN PLAINS WAVE AS IT LIFTS NORTHEAST THROUGH THE OHIO VALLEY...AND THE OTHER ON UPSTREAM SURFACE TROUGH. REGARDING SHORT WAVE TROUGH LIFTING NORTHEAST...BEST MID/UPPER LEVEL FORCING PASS ACROSS SOUTHERN LOWER MI...JUST GRAZING FAR SOUTHEAST PORTION OF FORECAST AREA. MAY SEE A FEW FLURRIES OUT OF IT OVERNIGHT AROUND SAGINAW BAY THOUGH LAYERS BETWEEN PERSISTENT SC DECK AND 700MB ARE STILL FAIRLY DRY. REGARDING UPSTREAM COLD FRONT/TROUGH...BAND OF FORCING/MOISTURE ASSOCIATED WITH UPSTREAM SURFACE FRONT/TROUGH...WITH SOME LIGHT SNOW/FLURRIES NORTH OF THE MN BORDER. EARLIER POST-TROUGH PRECIP ACROSS THE DAKOTAS HAS FALLEN APART...WHICH MATCHES GUIDANCE TRENDS OF KEEPING BETTER FORCING AND MOISTURE NORTH OF LAKE SUPERIOR AS FRONT WEAKENS. SO NOT EXPECTING MUCH EFFECT FROM THIS FEATURE ACROSS EASTERN UPPER OVERNIGHT. AND AS FAR AS LINGERING LES GOES...FLOW REMAINS SOUTHWEST OFF LAKE MICHIGAN THIS EVENING...GRADUALLY VEERING WEST/WEST-SOUTHWEST OVERNIGHT. LOW LEVEL WAA WILL PUSH INVERSION HEIGHTS DOWN BELOW 900MB (AND WARMER THAN -10C). SO WOULDN'T EXPECT MUCH MORE THAN FLURRIES BEYOND THIS EVENING...ALTHOUGH RUC/ETA BOTH SUGGEST DEVELOPMENT OF A NICE CONVERGENCE BAND ALONG THE NORTHWEST LOWER LAKESHORE AFTER MIDNIGHT...WHICH COULD SQUEEZE OUT SOMETHING A BIT MORE SUBSTANTIAL THAN FLURRIES. JPB SATURDAY...500 MB SHORTWAVE TROUGH MOVES THROUGH THE FORECAST AREA EARLY, WITH THE SFC HIGH IN PLACE OVER THE REGION. SO WILL KEEP THE FORECAST DRY. AT THE MOST, EXPECT SCATTERED FLURRIES IN THE SE PART OF THE FORECAST AREA, BUT GUT FEELING IS NOTHING HAPPENS IN THE MORNING AFTER THE 500 MB WAVE PASSES US. SATURDAY NIGHT/SUNDAY/SUNDAY EVENING...SW FLOW INCREASE IN THE EVENING, THEN AFTER 06Z, AS THE MOISTURE INCREASES ON THE NORTH END OF THE LAKE AND WITH THE TEMPERATURES FROM 850 MB AND BELOW STILL IN BELOW FREEZING, EXPECT THAT SW FLOW LES LOOKS LIKE A POSSIBILITY. THIS CONTINUES INTO SUNDAY MORNING. AROUND NOON, THE 850 MB AND 925 MB TEMPERATURES WARM ENOUGH TO DECREASE THE OVER LAKE INSTABILITY. HOWEVER, WITH THE MOISTURE IN THE LOWER LEVELS, BUT BELOW -10C, AND TEMPERATURES AT THE SFC AROUND FREEZING IN THE EARLY AFTERNOON AND THE EARLY EVENING. SO HAVE GONE WITH PATCHY DZ OR FZDZ. SUNDAY OVERNIGHT...850 TEMPERATURES BEGIN TO FALL OFF AFTER 06Z AS THE COLD FRONT MOVES THROUGH THE REGION. WITH THE NW FLOW, THE DELTA TS INCREASING TO AROUND 13C BY 12Z, AND THE TEMPERATURES IN THE LOWER LEVELS ALL BELOW FREEZING, WILL CHANGE THE MIX TO A CHANCE OF SNOW, BUT LEAVE THE POPS AT 30% DUE TO THE VARIABILITY THAT THE MODELS ARE SHOWING, THOUGH LAKE EFFECT LOOKS LIKE THE MOST PROBABLE OUTCOME AS OF NOW. EXTENDED(MONDAY THROUGH FRIDAY)...ENSEMBLE TODAY LOOKED PRETTY GOOD WITH NOGAPS, GEM AND GFS ENSEMBLES IN GOOD AGREEMENT THROUGH THE 7 DAY PERIOD. LOOKING AT THE OBSERVED 500 MB HEIGHTS OVER THE PAST MONTH IN A HOVMOLLER DIAGRAM, THE LONG WAVE RIDGE LOOKS TO BE RETROGRADING BACK TO THE WEST A BIT, SO THE ENSEMBLE/ECMWF FORECAST LOOKS THE BEST. THE OPERATIONAL FORECAST OF THE GFS, IS ON THE QUICK SIDE OF THINGS. SO THE FORECAST WILL LOOK LIKE THIS...MONDAY, MAIN SFC LOW IS OFF TO THE EAST AND THE ARCTIC BOUNDARY IS MOVING FROM THE NORTH. 850 TEMPERATURES ARE RUNNING AROUND -5C BY 12Z IN THE MORNING DOWN TO M-55 SO WILL GO WITH A CHANCE OF SNOW SHOWERS. MONDAY NIGHT AND TUESDAY, THE HIGH BUILDS IN PRETTY QUICKLY AND MOVES ON TO THE EAST ALMOST AS FAST. THIS LEADS TO RETURN FLOW ON TUESDAY MORNING. SO DRY WEATHER MONDAY NIGHT AND MOST OF TUESDAY. TUESDAY NIGHT THE CHANCE OF RAIN IN N LOWER AS THE WARM FRONT MOVES TOWARD THE AREA. WEDNESDAY, RAIN FOR THE WHOLE FORECAST AREA AS THE WARM FRONT GOES THROUGH IN THE MORNING. THURSDAY, THE COLD FRONT GOES THROUGH PRIOR TO 12Z SO FOR THE DAY THERE WILL BE A MIX OF SNOW AND RAIN IN THE MORNING AND THEN ALL SNOW BY THE AFTERNOON AS THE COLD AIR MOVES IN. FRIDAY, HIGH BEGINS TO BUILD INTO THE REGION, SO FIGURING ON LAKE EFFECT SNOW SHOWERS. WITH THE UNCERTAINTY OF DAY 7 WILL LEAVE IT OVER THE WHOLE FORECAST AREA UNTIL WE ARE SURE OF THE FLOW REGIME. LUTZ && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 111 PM EST FRI JAN 7 2005 .AVIATION... CEILINGS A BIT OF A CHALLENGE TODAY. GFS ONCE AGAIN SCATTERS OUT LOW CLOUDS AND ETA HANGS ON TO THEM. SIDING WITH ETA ON THIS ONE. FAIRLY THICK LAYER OF MID TO HIGH LEVEL CLOUDS HAVE MOVED IN ABOVE STRATOCUMULUS DECK...PREVENTING THEM FROM SCATTERING OUT. CURRENT OBS SHOWING AN EXPANSIVE AREA OF MVFR CLOUDS SOUTH AND WEST OF OUR FORECAST REGION. AS HIGH MOVES EAST...WINDS BACKING TO THE SOUTH THIS AFTERNOON WILL ALLOW THIS MORE EXPANSIVE DECK OF MVFR TO SLIDE INTO SOUTHEAST MICHIGAN...BUT EVENTUALLY EXPECT THESE LOW CLOUDS TO SCATTER OUT THIS EARLY EVENING. LOW CLOUDS RETURN AFTER MIDNIGHT AS NEXT SYSTEM BRUSHES BY TO OUR SOUTH. DTW AND DET LIKELY TO SEE A BOUT OF SNOW WITH THIS SYSTEM...ON THE ORDER OF AROUND AN INCH OF ACCUMULATING SNOW. A PERIOD OF IFR CAN BE EXPECTED IN HEAVIER SNOW SHOWERS TOWARD SUNRISE ON SATURDAY. SNOW WILL BE BRIEF AND OUT OF HERE BY MID TO LATE MORNING. $$ .UPDATE...ISSUED AT 1051 AM EST. UPDATED ZONES TO BLANKET ENTIRE AREA WITH A MENTION OF SCATTERED FLURRIES. NEARLY ALL OBS OVER SOUTHWEST MICHIGAN REPORTING LIGHT SNOW WITH VISIBILITIES B/W 1 AND 3 MILES. NO REPORTS AS OF YET OF ANY FLURRIES OVER SOUTHEAST MICHIGAN WITH THE EXCEPTION OF BAD AXE WHERE A FEW FLURRIES HAVE BEEN OCCURRING THERE THIS MORNING. CURRENT RUC ANALYSIS SHOWS A BIT OF A VORT MAX THROUGH THIS AREA WITH A SLIGHT BEND IN THE SURFACE PRESSURE ON THE NORTHWESTERN FLANK OF SURFACE HIGH NOW MOVING THROUGH OHIO. MOISTURE IS VERY SHALLOW (DTX RADAR OVERSHOOTING ALL OF THIS ACTIVITY)...SO DON'T ANTICIPATE ANYTHING MORE THAN FLURRIES THIS AFTERNOON. ALSO DECIDED TO GO MOSTLY CLOUDY FOR THE REMAINDER OF THE DAY. LOWER CLOUDS WILL HAVE A BETTER TIME HOLDING ON AS MID CLOUDS REMAIN ABOVE...SO EVEN AS LOW CLOUDS DO SLOWLY SCATTER OUT...THERE WILL BE ENOUGH MID LEVEL CLOUDS TO WARRANT MOSTLY CLOUDY TODAY. TEMPS LOOK GOOD...NO CHANGES THERE. $$ .SHORT TERM...ISSUED AT 310 AM EST. FLURRIES DIMINISHING QUICKLY WEST OF MBS AND FNT AS 850 TEMPERATURES CONTINUE TO WARM AND INVERSION HEIGHTS FALL TO LESS THAN 3K FT OVER LAKE MICHIGAN...SO WILL NOT MENTION ANY FLURRIES EARLY THIS MORNING IN ZONE PACKAGE. LARGE AREA OF LOW CLOUDS SNEAKING IN UNDER INVERSION THOUGH AND FILLING IN THE FEW HOLES THAT DEVELOPED OVERNIGHT. LOOKS LIKE 40KM RUC HAS A GOOD HANDLE ON SOUTHERN EXTENT OF LOW CLOUDS OVER THE OHIO VALLEY AND TIMING THIS BACK EDGE THROUGH THE SOUTH HALF OF THE CWA THIS MORNING. WILL USE 925 MB 70 PERCENT RH LINE AS A GUIDE. WILL HAVE TO CONTEND WITH MID LEVEL CLOUD DECK STREAMING NORTHWARD LATER THIS MORNING...AS WEAK UPPER WAVE OVER KANSAS/MISSOURI MOVES INTO THE LOWER GREAT LAKES. LOOKS LIKE THE AC DECK WILL ARRIVE SOMETIME AFTER 15Z...SO WILL JUST WORD ZONES AS MOSTLY CLOUDY...WITH ONLY BRIEF WINDOW OF SOME SUNSHINE LATER THIS MORNING. ETA/GFS APPEAR TO HAVE A GOOD HANDLE ON UPPER WAVE CURRENTLY OVER SOUTH DAKOTA...WHICH IS FCST TO SWEEP THROUGH THE LOWER GREAT LAKES LATE TONIGHT. MODELS SHOW GOOD OMEGA FIELD WITH THIS WAVE...WITH A 6 HOUR SHOT OF GOOD 1000-500 DPVA. MODELS EVEN SHOW A WEDGE OF POTENTIAL INSTABILITY OVER DTW AS 500 MB TEMPERATURES COOL TO -26C. WOULD LIKE TO SEE BETTER JET POSITION THOUGH...AS RIGHT REAR QUADRANT DROPS INTO OHIO VALLEY. WILL ADJUST POPS TO 60 PERCENT FAR SOUTH WITH AROUND AN INCH ACCUMULATION...THEN CHANCE POPS TO PTK AND FNT...MBS SOUNDINGS MAINTAIN A DRY WEDGE BETWEEN 5K AND 10K FEET AS WAVE TRACKS EAST...VERY WEAK ADIABATIC OMEGA ON 295K SFC NORTH OF FNT WITH CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 30 AND 50 MB. && .LONG TERM...SATURDAY THROUGH THURSDAY VERY COMPLICATED FLOW STRUCTURE HAS SET UP ACROSS THE EASTERN PACIFIC AND WESTERN NORTH AMERICA. THE EVOLUTION OF THESE FEATURES WILL ULTIMATELY HAVE AN IMPACT ON THE EASTERN CONUS AS THE CURRENT SPLIT FLOW CONFIGURATION ACROSS THE WEST BEGINS TO BREAK DOWN THROUGH NEXT WEEK. NUMERICAL SUITE HAVING SOME DIFFICULTY DEPICTING THE FEATURES OFF THE WEST COAST. THE GFS/WRFXX OFFER THE BEST DEPICTION WITH THE STRONG SHORTWAVE DIGGING SOUTH OUT OF BRITISH COLUMBIA, WHICH WILL BE THE MAJOR PLAYER WITH THE RE-ESTABLISHMENT OF THE LONG WAVE TROUGH ACROSS THE WEST OVER THE WEEKEND. STILL DON'T HAVE A GREAT DEAL OF CONFIDENCE ON THE OVERALL EVOLUTION OF THE WESTERN TROUGH AND THE SHORTWAVES THAT SHED EAST ACROSS THE CONUS IN RESPONSE TO THE INTERACTION WITH THE SUB-TROPICAL JET, GIVEN THE COMPLEX INTERACTIONS TAKING PLACE OUT THERE RIGHT NOW. UNTIL THE 18Z CYCLE EVEN THE GFS WAS FAR TOO UNDERAMPLIFIED THE BROAD LONGWAVE RIDGE WILL REMAIN IN PLACE ACROSS THE EASTERN CONUS THROUGH MUCH OF NEXT WEEK. BAROCLINICITY WILL CONTINUE TO BE QUITE HIGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGION THROUGH THE WEAK. THE THERMAL GRADIENT WILL WASH NORTH THROUGH THE FORECAST AREA ON SUNDAY AS HEIGHTS ALOFT BUILD IN ADVANCE OF AN EJECTING SHORTWAVE PROGGED TO MOVE THROUGH ONTARIO ON MONDAY. THE LOW LEVEL FRONT IS PROJECTED TO SLOSH BACK AND FORTH THROUGH THE REGION FOR MUCH OF THE WEEK. THIS WILL KEEP CONDITIONS SOMEWHAT UNSETTLED ALL WEEK LONG. HOWEVER, IT CERTAINLY WILL NOT FEEL LIKE EARLY JANUARY AS HIGHS SHOULD CLIMB WELL INTO THE 40S EARLY TO MID WEEK- BUT PLENTY OF WET WEATHER TO GO ALONG WITH IT. EVENTUALLY, HEIGHT FALLS ACROSS CENTRAL CANADA WILL BECOME ESTABLISHED ACROSS THE NORTHERN CONUS TRANSLATING THE WESTERN US TROUGH EASTWARD- THUS RETURNING THE FORECAST AREA BACK TO MORE SEASONABLE CONDITIONS BY WEEK'S END. && .AVIATION...ISSUED AT 1155 PM EST THURSDAY STRATUS DECK IS SLOWLY ADVANCING ACROSS THE FORECAST AREA... WITH TAF SITES ALREADY UNDER VFR CIGS. SOME CONVERGENCE OFF LAKE MICHIGAN IS PRODUCING SOME FLURRIES ACROSS SOUTHERN MICHIGAN. THE LAKE HAS ALSO APPEARED TO RAISE INVERSIONS A BIT. CEILINGS HAVE ACTUALLY RISEN TO AROUND 4K FT OVER MOST OF SE MICHIGAN. HOWEVER... MVFR CIGS ARE QUITE WIDESPREAD ACROSS INDIANA AND ILLINOIS. THEY ARE ALSO BEGINNING TO LOWER OVER SW MI AS INVERSION HEIGHTS FALL. AS THE BOUNDARY LAYER FLOW BACKS SOUTHWESTERLY LATE TONIGHT... EXPECT SOME OF THESE LOWER CLOUDS WILL LIFT NORTH. SOME DRYER LOW LEVEL AIR... APPARENT OVER SOUTHERN/CENTRAL MISSOURI WILL LIFT INTO SOUTHERN MICHIGAN LATE FRI MORNING. THIS COMBINED WITH ANTICYCLONIC LOW LEVEL FLOW AND LOWERING INVERSIONS SHOULD SCOUR OUT THE LOW CLOUDS BY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ GSS/MANN/SHULER mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 1030 AM CST FRI JAN 7 2005 .UPDATE... UPDATING FORECAST TO REMOVE MORNING WORDING. FORECAST ON TRACK WITH INCREAING RAIN CHANCES THIS AFTERNOON. TWEAKED AFTERNOON HIGHS SLIGHTLY SRN ZONES. CLOUD COVER AND ISOLATED SHOWERS WILL KEEP TEMPERATURES RELATIVELY COOL BEFORE WARM FRONT FINALLY LIFTS NWD. && .SYNOPSIS... A WEAK SURFACE LOW(1013MB) IN WRN GULF WILL TRACK NEWD AS IT LIFTS A STATIONARY FRONT ALONG THE COAST INLAND. LOW SHOULD TRACK ACROSS CENTRAL LA INTO SRN MS BETWEEN KHEZ AND KMCB BY EARLY AFTERNOON. EXPECT THE LOW TO TRACK BETWEN KMEI AND KCBM DURING THE EVENING TAKING THE REMAINING RAINFALL E OF THE CWFA SOMETIME AFTER MIDNIGHT TONIGHT. THEN A HIGH PRESSURE RIDGE BUILDS FROM THE OH VALLEY TO THE TX COAST SATURDAY EASING SEWD TO THE CAROLINA COAST BY MONDAY UNDER NEARLY ZONAL FLOW ALOFT ACROSS THE SRN HALF OF THE CONUS. NEXT WEEK...A POLAR VORTEX ROTATES FROM CENTRAL CANADA TOWARD HUDSON BAY CARVING OUT A DEEP UPPER TROUGH AXIS OVER CENTRAL NA BY WEDNESDAY. THIS TROUGH MOVES THROUGH ERN CONUS BY FRIDAY BRINGING A CHANGE BACK TO WINTER COLD FOR THE REGION. && .SHORT TERM... ISENTROPIC LIFT ALREADY UNDERWAY OVER MAINLY N HALF OF MS WHERE SOME MIXED PRECIP POSSIBLE FOR A FEW HOURS THIS MORNING. GFS/RUC HANDLING THE INITIAL ZONE OF RAINFALL BEST AND LOOK FOR MORE RAIN TO BREAK OUT OVER WRN 2/3 OF OUR CWFA BY LATE MORNING AS GULF LOW MOVES ONSHORE. RAINS SHOULD CONTINUE EXPANDING THIS AFTERNOON WITH SOME DECENT DOWNPOURS AS PWATS RISE CLOSE TO 1.5 INCHES. BEST WARMING THIS AFTERNOON AND INSTABILITY SHOULD DEVELOP OVER SERN MS. EVEN SO...7-5H LAPSE RATES 5.5-6C WITH SHOWALTERS 0 TO -1 BY EVENING AS BEST UVV CROSSES NWRN HALF OF FA WHERE TOTALS REACH A MORE IMPRESSIVE 51. INCREASING UPPER DIVERGENCE SHOULD PERSIST FROM 18Z-06Z BEFORE SYSTEM PULLS E WHILE LOW LEVEL CONVERGENCE FIELDS NEVER DO GET VERY IMPRESSIVE. ALL IN ALL...LOOK FOR WIDESPREAD 1 INCH RAINS AND LOCALLY 2 INCHES BEFORE ENDING PRIOR TO SUNRISE SATURDAY. DRYING OUT PROCESS AND CLEARING SATURDAY MORNING WILL SET UP A MOSTLY CLEAR SATURDAY NIGHT WITH LIGHT N WINDS. LOOK FOR A RETURN TO SLY FLOW ON SUNDAY WITH MORE HIGH LEVEL MOISTURE STREAMING BACK INTO THE REGION AS WARMING TREND A GOOD BET GOING INTO THE MEDIUM RANGE. .LONG TERM... MILDER AIRMASS THAT STARTS SUNDAY AFTERNOON SHOULD HOLD THROUGH THE MIDDLE OF NEXT WEEK WITH HIGHS FREQUENTLY TOPPING 70F ONCE AGAIN MONDAY THROUGH WEDNESDAY. WIND FIELDS INTENSIFY WITH A POTENTIAL OF STRONG/SEVERE THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY AS A STRONG COLD FRONT CROSSES THE REGION THURSDAY. WILL NEED TO CONTINUE MONITORING MODEL TRENDS FOR THIS SYSTEM AS THE POLAR VORTEX MOVING S IN CANADA JERKS A PIECE OF SIBERIAN AIR INTO NA. THIS AIRMASS DIVES TOWARD THE NRN CONUS NEXT FRIDAY SETTING US UP FOR ANOTHER COLD HOLIDAY WEEKEND. /#40/ && .AVIATION...TRAINING PRECIPITATION AREA OVER THE NORTHERN PART OF THE FORECAST AREA IS EXPECTED TO SHIFT NORTH AND EAST TODAY AS LOW PRESSURE OFF THE MIDDLE TEXAS COAST MOVES NORTHEAST. THIS AREA OF LOW PRESSURE...IN CONJUNCTION WITH A PASSING SHORTWAVE TROUGH...WILL PULL A WARM FRONT NORTH ACROSS THE FORECAST AREA. ISENTROPIC FIELDS SUGGEST THE FOCUS FOR HEAVIER RAINFALL WILL SHIFT TO THE SOUTHEAST PART OF THE FORECAST AREA BY THIS AFTERNOON/EVENING. CEILINGS -- ALL OF THE STRATUS/PRECIPITATION WILL TEND TO KEEP CEILINGS IN THE MVFR OR IFR TERRITORY THROUGH 1200 UTC SATURDAY. HOWEVER...IN CONJUNCTION WITH THE PUBLIC FORECASTER...I'LL START LIFTING CEILING RESTRICTIONS AROUND GLH AND GWO TOWARD THE END OF THE TAF PERIOD. VISIBILITIES AND ANY RESTRICTIONS -- I PLAN ON MAKING MANY CHANGES FROM THE ONGOING TAFS HERE...WITH MOST VISIBILITIES IN IFR TO MAYBE MVFR TERRITORY. THERE COULD BE SOME ELEVATED TS AROUND HBG BY AFTERNOON AS THE FRONT LIFTS NORTH...BUT DUE TO UNCERTAINTIES...I WON'T MENTION THIS IN THE TAF AT THIS TIME. SO IN GENERAL...LOOK FOR RESTRICTIONS TO BE EITHER RA/SHRA...WITH A SPLASH AND DASH OF BR. WINDS -- NORTHEAST TO EAST WINDS WILL BECOME SOUTHEASTERLY AT 5 TO 10 KNOTS AS THE WARM FRONT LIFTS NORTH...ALTHOUGH THIS MAY NOT OCCUR AT GLH/GWO (BECAUSE THE FRONT WILL REMAIN SOUTH). BY 1200 UTC SATURDAY...WINDS WILL PROBABLY BECOME NORTHERLY AGAIN AS THE FRONT SHIFTS EAST. /BUTTS/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 58 51 58 46 / 100 100 20 10 MERIDIAN 62 52 64 44 / 90 100 30 10 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ WFO JAN/03 ms AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 340 PM CST FRI JAN 7 2005 .DISCUSSION... CORRECTED TO ADD EXTENDED FORECAST DISCUSSION A BAND OF HEAVY SNOW HAS BLOSSOMED FROM BUTLER TO CLINTON TO SEDALIA TO BOONVILLE THIS AFTERNOON. THE REFLECTIVITY GRADIENT ON THE NORTHERN EDGE OF THE SNOW BAND IS ABOUT AS SHARP AS I'VE EVER SEEN. AT THIS HOUR IT IS SNOWING HEAVILY JUST SOUTH OF WARRENSBURG. MOTORISTS DRIVING SOUTH OF WARRENSBURG WILL ENCOUNTER A WALL OF SNOW JUST SOUTH OF TOWN. CALLS TO OBSERVERS IN THE SNOW BAND REPORT RATES OF AN INCH PER HOUR. THE BAND IS MOVING RAPIDLY, BUT I AM CONCERNED THAT THE CENTER OF THE VORTICITY MAX IS STILL OVER THE WICHITA AREA. THERE COULD BE ANOTHER 2 OR 3 HOURS OF LIFT FOR THE COMMUNITIES MENTIONED ABOVE. INFRARED SATELLITE PICTURES SHOW COLD CLOUD TOPS ADVECTING INTO SOUTHEAST KANSAS, SO I WOULDN'T RULE OUT SOME REDEVELOPMENT OF SNOW ON THE BACK END OF THE SNOW BAND THROUGH SUNSET. FORECASTING CLOUDS AND TEMPERATURES WILL BE THE BIG CHALLENGE THIS WEEKEND. LOW STRATUS IS LOCATED ALONG THE 925MB TROUGH AXIS RUNNING FROM NORTHWEST IOWA THROUGH SOUTH CENTRAL KANSAS THIS AFTERNOON. THE MODELS DAMPEN THE TROUGH AXIS THIS EVENING AND LOW LEVEL WINDS ARE FORECAST DECREASE LATE TONIGHT AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. THE ETA MAY BE TOO AGGRESSIVE SCOURING OUT LOW LEVEL MOISTURE GIVEN THE AMOUNT OF SNOW AND ICE ON THE GROUND. I'VE LIMITED FOG TO EASTERN KANSAS AND NORTHWEST MISSOURI TONIGHT THINKING THAT STRATUS WILL LINGER OVER CENTRAL AND EASTERN MISSOURI MOST OF THE NIGHT. FOG AND STRATUS COULD HAVE A BIG IMPACT ON TEMPERATURES TOMORROW. IF STRATUS DOES NOT BREAK UP TONIGHT SOUTH WINDS OVER THE TOP OF A MORNING INVERSION MAY LOCK STRATUS IN FOR A GOOD PORTION OF THE DAY. DEPENDING ON THE AMOUNT OF SUN WE GET TOMORROW, TEMPERATURES COULD SHOOT UP INTO THE LOWER 40S OR REMAIN NEAR FREEZING. I'VE CUT THE DIFFERENCE WITH HIGHS IN THE 30S FOR MOST OF THE REGION. THE SAME ARGUMENTS FOR FOG, STRATUS, AND SNOW/ICE COVER WILL COME INTO PLAY ON SUNDAY. STRONGER MIXING SHOULD PUSH TEMPERATURES INTO THE 50S AS PREVIOUSLY ADVERTISED, BUT STRATUS CAN BE STUBBORN THIS TIME OF YEAR. KOCH TEMPERATURES SHOULD REMAIN MILD AT THE START OF NEXT WEEK AS SOUTHERLY FLOW CONTINUES TO DRAW WARM AIR AND GULF MOISTURE NORTHWARD AHEAD OF AN APPROACHING DEEP UPPER TROUGH. PRECIPITATION IS EXPECTED TO BEGIN AS EARLY AS MONDAY AS A WEAK FRONT PASSES SOUTHEAST ACROSS THE AREA AND MAY INTERACT WITH WEAK IMPULSES EJECTING FROM THE WESTERN TROUGH. THE GFS WANTS TO BRING THE FRONT BACK NORTH ON TUESDAY AS A WARM FRONT...WHICH WOULD ALLOW FOR OVERRUNNING PRECIPITATION TO DEVELOP AS ISENTROPIC UPGLIDE INCREASES. MAY SEE SOME RECURRING FLOODING PROBLEMS ON AREA WATERWAYS WITH PERIODS OF MODERATE RAIN LASTING INTO MID-WEEK. THE DEEP WESTERN TROUGH WILL ADVANCE EAST ACROSS THE CENTRAL STATES...PUSHING AN ARCTIC FRONT ACROSS THE FORECAST AREA DURING THE MIDDLE OF NEXT WEEK. THE QUANDARY REMAINS AS TO HOW FAR SOUTH THE ARCTIC AIR WILL EXTEND. HAVE CONTINUED TO MENTION A RAIN/SNOW MIX ON WEDNESDAY IN NORTHWEST MISSOURI AND WEDNESDAY NIGHT FOR THE REMAINING FORECAST AREA...CHANGING OVER TO SNOW TOWARD THE TAIL END OF THE EVENT INTO THURSDAY. WILL NEED TO MONITOR FUTURE MODEL DATA TO SORT OUT WINTER PRECIPITATION TYPE FOR NEXT WEEK. STOFLET && .PREVIOUS DISCUSSION... 1205 PM... A POTENT VORTICITY MAXIMA IS TRACKING THROUGH THE TEXAS PANHANDLE AND PRECIPITATION IS DEVELOPING OVER NORTHEAST OKLAHOMA AND SOUTHEAST KANSAS LATE THIS MORNING. THE RUC, GFS, AND ETA INITIALIZED THIS FEATURE WELL AT 12Z, AND THE VORTICITY MAX WILL LIKELY BE STRONG ENOUGH TO BRING A QUICK BURST OF SNOW TO BUTLER, CLINTON, AND SEDALIA LATE THIS AFTERNOON AND EARLY THIS EVENING. THE SPRINGFIELD SOUNDING FROM THIS MORNING SHOWED A SIGNIFICANT DRY MID LAYER, BUT MOISTURE WILL BE ADVECTED QUICKLY NORTH FROM EAST TEXAS THIS AFTERNOON. EVAPORATIVE COOLING WILL BE SUFFICIENT TO CAUSE PRECIPITATION TO BE SNOW TO THE CITIES LISTED ABOVE. I AM EXPECTING A WINDOW OF 3 OR 4 HOURS WITH THIS QUICK MOVING VORT MAX, SO SNOW AMOUNTS WILL BE LESS THAN AN INCH. KOCH && .AVIATION DISCUSSION... 1130 AM... STRONG SHORTWAVE CURRENTLY CENTERED ALONG THE KS/OK BORDER AROUND DDC WILL QUICKLY MOVE EAST ACROSS SOUTHERN MISSOURI THIS EVENING. MOISTURE LACKING FOR ANY FROZEN PRECIPITATION FOR THE KC/STJ TERMINAL LOCATIONS. PRECIPITATION SHOULD REMAIN TO THE SOUTH AND EAST. MAIN CONCERN IS THE DEVELOPMENT/ADVECTION OF LOW CLOUD DECK CURRENTLY PREVAILING ACROSS NORTHCENTRAL KANSAS AND SE NEBRASKA. LOW CLOUD DECK WAS IN THE VICINITY OF SURFACE TROUGH/COLD FRONT IN SE NEBRASKA. AS THE SHORTWAVE PROGRESSES EAST LATE THIS AFTERNOON...THE FRONT WILL DROP INTO NW MISSOURI LATE THIS AFTERNOON. MESOETA GRIDS CONFIRM THAT LOW CLOUD DECK WILL DROP SE WITH THE SURFACE TROUGH. HAVE INTRODUCED IFR CIGS AND MVFR VSBYS FOR LATE THIS AFTERNOON WITH CIGS DROPPING TO AROUND LIFR STATUS THIS EVENING. WITH ONLY WEAK SUBSIDENCE AND WINDS IN THE 925-SFC LAYER...LOW CLOUDS WILL LINGER THROUGH THE ENTIRE NIGHT...LONGER THAN THE MESOETA MODEL SUGGEST. CURRENTLY HAVE LOW CLOUD DECK CLEARING BY 12Z SATURDAY...HOWEVER...HAVE SOME CONCERN THAT THE LOW CLOUD DECK COULD LINGER THROUGH MUCH OF THE MORNING WITH ONLY WEAK SOLAR INSOLATION AND BOUNDARY LAYER FLOW SWITCHING BACK TO THE SOUTH. DB && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 340 PM CST FRI JAN 7 2005 .DISCUSSION... A BAND OF HEAVY SNOW HAS BLOSSOMED FROM BUTLER TO CLINTON TO SEDALIA TO BOONVILLE THIS AFTERNOON. THE REFLECTIVITY GRADIENT ON THE NORTHERN EDGE OF THE SNOW BAND IS ABOUT AS SHARP AS I'VE EVER SEEN. AT THIS HOUR IT IS SNOWING HEAVILY JUST SOUTH OF WARRENSBURG. MOTORISTS DRIVING SOUTH OF WARRENSBURG WILL ENCOUNTER A WALL OF SNOW JUST SOUTH OF TOWN. CALLS TO OBSERVERS IN THE SNOW BAND REPORT RATES OF AN INCH PER HOUR. THE BAND IS MOVING RAPIDLY, BUT I AM CONCERNED THAT THE CENTER OF THE VORTICITY MAX IS STILL OVER THE WICHITA AREA. THERE COULD BE ANOTHER 2 OR 3 HOURS OF LIFT FOR THE COMMUNITIES MENTIONED ABOVE. INFRARED SATELLITE PICTURES SHOW COLD CLOUD TOPS ADVECTING INTO SOUTHEAST KANSAS, SO I WOULDN'T RULE OUT SOME REDEVELOPMENT OF SNOW ON THE BACK END OF THE SNOW BAND THROUGH SUNSET. FORECASTING CLOUDS AND TEMPERATURES WILL BE THE BIG CHALLENGE THIS WEEKEND. LOW STRATUS IS LOCATED ALONG THE 925MB TROUGH AXIS RUNNING FROM NORTHWEST IOWA THROUGH SOUTH CENTRAL KANSAS THIS AFTERNOON. THE MODELS DAMPEN THE TROUGH AXIS THIS EVENING AND LOW LEVEL WINDS ARE FORECAST DECREASE LATE TONIGHT AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. THE ETA MAY BE TOO AGGRESSIVE SCOURING OUT LOW LEVEL MOISTURE GIVEN THE AMOUNT OF SNOW AND ICE ON THE GROUND. I'VE LIMITED FOG TO EASTERN KANSAS AND NORTHWEST MISSOURI TONIGHT THINKING THAT STRATUS WILL LINGER OVER CENTRAL AND EASTERN MISSOURI MOST OF THE NIGHT. FOG AND STRATUS COULD HAVE A BIG IMPACT ON TEMPERATURES TOMORROW. IF STRATUS DOES NOT BREAK UP TONIGHT SOUTH WINDS OVER THE TOP OF A MORNING INVERSION MAY LOCK STRATUS IN FOR A GOOD PORTION OF THE DAY. DEPENDING ON THE AMOUNT OF SUN WE GET TOMORROW, TEMPERATURES COULD SHOOT UP INTO THE LOWER 40S OR REMAIN NEAR FREEZING. I'VE CUT THE DIFFERENCE WITH HIGHS IN THE 30S FOR MOST OF THE REGION. THE SAME ARGUMENTS FOR FOG, STRATUS, AND SNOW/ICE COVER WILL COME INTO PLAY ON SUNDAY. STRONGER MIXING SHOULD PUSH TEMPERATURES INTO THE 50S AS PREVIOUSLY ADVERTISED, BUT STRATUS CAN BE STUBBORN THIS TIME OF YEAR. KOCH .PREVIOUS DISCUSSION... 1205 PM... A POTENT VORTICITY MAXIMA IS TRACKING THROUGH THE TEXAS PANHANDLE AND PRECIPITATION IS DEVELOPING OVER NORTHEAST OKLAHOMA AND SOUTHEAST KANSAS LATE THIS MORNING. THE RUC, GFS, AND ETA INITIALIZED THIS FEATURE WELL AT 12Z, AND THE VORTICITY MAX WILL LIKELY BE STRONG ENOUGH TO BRING A QUICK BURST OF SNOW TO BUTLER, CLINTON, AND SEDALIA LATE THIS AFTERNOON AND EARLY THIS EVENING. THE SPRINGFIELD SOUNDING FROM THIS MORNING SHOWED A SIGNIFICANT DRY MID LAYER, BUT MOISTURE WILL BE ADVECTED QUICKLY NORTH FROM EAST TEXAS THIS AFTERNOON. EVAPORATIVE COOLING WILL BE SUFFICIENT TO CAUSE PRECIPITATION TO BE SNOW TO THE CITIES LISTED ABOVE. I AM EXPECTING A WINDOW OF 3 OR 4 HOURS WITH THIS QUICK MOVING VORT MAX, SO SNOW AMOUNTS WILL BE LESS THAN AN INCH. KOCH .AVIATION DISCUSSION... 1130 AM... STRONG SHORTWAVE CURRENTLY CENTERED ALONG THE KS/OK BORDER AROUND DDC WILL QUICKLY MOVE EAST ACROSS SOUTHERN MISSOURI THIS EVENING. MOISTURE LACKING FOR ANY FROZEN PRECIPITATION FOR THE KC/STJ TERMINAL LOCATIONS. PRECIPITATION SHOULD REMAIN TO THE SOUTH AND EAST. MAIN CONCERN IS THE DEVELOPMENT/ADVECTION OF LOW CLOUD DECK CURRENTLY PREVAILING ACROSS NORTHCENTRAL KANSAS AND SE NEBRASKA. LOW CLOUD DECK WAS IN THE VICINITY OF SURFACE TROUGH/COLD FRONT IN SE NEBRASKA. AS THE SHORTWAVE PROGRESSES EAST LATE THIS AFTERNOON...THE FRONT WILL DROP INTO NW MISSOURI LATE THIS AFTERNOON. MESOETA GRIDS CONFIRM THAT LOW CLOUD DECK WILL DROP SE WITH THE SURFACE TROUGH. HAVE INTRODUCED IFR CIGS AND MVFR VSBYS FOR LATE THIS AFTERNOON WITH CIGS DROPPING TO AROUND LIFR STATUS THIS EVENING. WITH ONLY WEAK SUBSIDENCE AND WINDS IN THE 925-SFC LAYER...LOW CLOUDS WILL LINGER THROUGH THE ENTIRE NIGHT...LONGER THAN THE MESOETA MODEL SUGGEST. CURRENTLY HAVE LOW CLOUD DECK CLEARING BY 12Z SATURDAY...HOWEVER...HAVE SOME CONCERN THAT THE LOW CLOUD DECK COULD LINGER THROUGH MUCH OF THE MORNING WITH ONLY WEAK SOLAR INSOLATION AND BOUNDARY LAYER FLOW SWITCHING BACK TO THE SOUTH. DB && .PREVIOUS DISCUSSION... 351 AM MAIN CONCERN IS TEMPS THROUGH THE NEXT FEW DAYS. EXPECT STRATOCU TO PERSIST ACROSS THE AREA THROUGH MUCH OF TODAY WITH WEAK ISENTROPIC LIFT CONTINUING AHEAD OF A WEAK SHORTWAVE MOVING ACROSS THE REGION. MAY EVEN SEE SOME MORE SCATTERED FLURRIES ASSOCIATED WITH THIS LIFT AS WELL. BEST CHANCE TO SEE FLURRIES IS IN THE NORTHWEST CORNER OF MISSOURI...CLOSEST TO THE SHORTWAVE. ONCE AGAIN EXPECT THE CLOUDS TO BE ON THE DECREASE THIS EVENING AND OVERNIGHT...GIVING ANOTHER CHILLY NIGHT WITH TEMPS FALLING INTO THE TEENS TO AROUND 20 DEGREES. MAY ALSO SEE SOME PATCHY FOG BUT WILL PROBABLY HAVE TO WAIT ON THAT UNTIL THE RIDGE MOVES EAST. HIGH PRESSURE IS QUITE OFTEN SLOW TO MOVE EAST SO LOWERED HIGHS ON SATURDAY TO SEVERAL DEGREES BELOW GUIDANCE...TO ACCOUNT FOR VERY LITTLE MIXING AND A RELATIVELY COOL START. HIGH MOVES EAST BY SATURDAY NIGHT...SETTING UP RETURNING MOISTURE AND A MUCH BETTER CHANCE FOR AREAS OF FOG. HAVE JUST A SMALL CHANGE IN TEMPS FROM SATURDAY HIGHS TO LOWS SUNDAY MORNING. THE WARMER TEMPS WILL GENERALLY CONTINUE THROUGH TUESDAY. ALTHOUGH THE ETA IS SHOWING A COLD FRONT MOVING ACROSS THE REGION SUNDAY NIGHT INTO MONDAY...WHICH WILL HAVE TO BE WATCHED. DIFFERENCE BETWEEN ETA AND GFS HIGHS ON MONDAY IS ABOUT 25 DEGREES. SO LEFT HIGHS WHERE THEY WERE...GOING COOLER THAN GFS AND WARMER THAN ETA. BUT IF GFS COMES IN CLOSER TO THE ETA...HIGHS TEMPS WILL HAVE TO BE LOWERED SIGNIFICANTLY ON MONDAY. NRR && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 251 PM CST FRI JAN 7 2005 ...WINTER WEATHER ADVISORY POSTED FOR THIS AFTERNOON AND EVENING... .DISCUSSION... SHORT TERM (TONIGHT)... POWERFUL VORTICITY MAXIMUM CONTINUES TO PIVOT EASTWARD ALONG THE OK/KS BORDER TOWARD THE OZARKS. STRONG OMEGA OUT AHEAD OF THIS SYSTEM IS BEGINNING TO INTERACT WITH THE LOW LEVEL MOISTURE SURGING NORTHWARD (NOTE THE STRATUS SURGING INTO THE AREA). CROSS SECTIONS FROM THE ETA AND RUC BOTH INDICATE A LAYER OF STRONGLY NEGATIVE EQUIVALENT POTENTIAL VORTICITY...WHICH IS INDICATIVE OF STRONG INSTABILITY. AS THE STRONG VORT INTERACTS WITH THE ELEVATED INSTABILITY LOOK FOR A BAND OF CONVECTIVE SNOW/SLEET TO MARCH EASTWARD ACROSS THE CWA LATE THIS AFTERNOON INTO THIS EVENING...WITH A ROGUE LIGHTING STRIKE OR TWO NOT OUT OF THE QUESTION. GIVEN THE RAPID ONSET AND UNEXPECTED NATURE OF THE SNOW...IN ADDITION TO THE TIMING (AROUND RUSH HOUR)...AS WELL AS THE INTENSITY OF THE SNOWFALL...WE HAVE POSTED A WINTER WEATHER ADVISORY THROUGH MID EVENING. SNOW SHOULD END FROM WEST TO EAST BY MID EVENING AS THE VORT MOVES ACROSS THE AREA. ALREADY GETTING REPORTS OF 2-3" IN THE PITTSBURG KS AREA EASTWARD TOWARD LAMAR...SO A QUICK 1-2" INCHES OF SNOW LOOKS REASONABLE MOST AREAS. GIVEN THE CONVECTIVE ELEMENTS IN THE BAND OF SNOW...POTENTIAL DOES EXIST FOR A ROGUE 3" AMOUNT HERE OR THERE. GRIDS AND TEXT PRODUCTS HAVE ALL BEEN UPDATED TO ACCOUNT FOR THE LATEST THINKING. IZZI LONG TERM (SATURDAY THROUGH FRIDAY)... THE UPPER PATTERN WILL INITIALLY FLATTEN IN THE WAKE OF THE SHORTWAVE PASSING THROUGH THE AREA TONIGHT. MEDIUM RANGE MODELS CONTINUE TO ADVERTISE A DEEP UPPER TROUGH THAT WILL TRANSLATE EASTWARD FROM THE WESTERN U.S. NEXT WEEK. SOUTHERLY FLOW AHEAD OF THIS SYSTEM WILL RESULT IN A SIGNIFICANT WARM UP BY SUNDAY WITH HIGHS NEAR 60. THE WARMING WILL BE SLOWED EARLY NEXT WEEK AS A FRONT SAGS SOUTHWARD INTO THE AREA. UNCERTAINTY EXISTS WHERE THIS FRONT WILL STALL BUT IT WILL REMAIN IN CLOSE PROXIMITY TO THE FORECAST AREA. INITIAL MINOR SHORTWAVES EJECTING OUT OF THE WESTERN TROUGH WILL INTERACT WITH THIS FRONT AND INCREASING MOISTURE TO PRODUCE RAIN CHANCES MONDAY INTO TUESDAY. THE MAIN ARCTIC BOUNDARY WILL APPROACH THE AREA BY MID WEEK AS THE UPPER TROUGH MIGRATES EAST INTO THE CENTRAL U.S. IT APPEARS AT THIS TIME THAT MOISTURE WILL BE READILY AVAILABLE TO PRODUCE SIGNIFICANT RAINFALL. SOME QUESTION TO HOW FAR SOUTH THE ARCTIC AIR WILL INTRUDE WHICH COULD RESULT IN A ROUND OF WINTERY WEATHER. MANY QUESTIONS REMAIN ON THE EVOLUTION OF THIS SYSTEM BUT THE POTENTIAL OF HEAVY RAINFALL AND WINTER WEATHER WILL NEED TO MONITORED CLOSELY. FOSTER && .AVIATION... TAFS HAVE BEEN AMENDED TO INCLUDE THE BAND OF SNOW/SLEET THAT HAS RAPIDLY DEVELOPED. SNOW WILL BE HEAVY AT TIMES AND WILL LIKELY REDUCE VISIBILITIES TO LIFR IN THE HEAVIER BURSTS. SNOW SHOULD END THIS EVENING...WITH IT STILL LOOKING AS THOUGH THE LOW CLOUDINESS WILL HANG AROUND MUCH OF THE NIGHT. ASSUMING THE LOW CLOUDINESS HANGS AROUND THEN THE THREAT OF RADIATION FOG WILL BE NIL. WITH LIMITED MIXING/LIGHT WINDS ITS POSSIBLE THE STRATUS COULD ATTEMPT TO BUILD DOWNWARD. FOR NOW HAVE TAKEN AN OPTIMISTIC APPROACH AND DIDNT BRING CIGS DOWN TO IFR OR LOWER...BUT THAT IS SOMETHING THAT WILL NEED TO BE MONITORED AND CONSIDERED IN LATER TAFS. IZZI && .SGF WATCHES/WARNINGS/ADVISORIES... .MO...WINTER WX AD UNTIL 9 PM NORTH OF A BRANSON TO EMINENCE LINE. .KS...WINTER WX AD UNTIL 9 PM. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 1205 AM CST FRI JAN 7 2005 .DISCUSSION... A POTENT VORTICITY MAXIMA IS TRACKING THROUGH THE TEXAS PANHANDLE AND PRECIPITATION IS DEVELOPING OVER NORTHEAST OKLAHOMA AND SOUTHEAST KANSAS LATE THIS MORNING. THE RUC, GFS, AND ETA INITIALIZED THIS FEATURE WELL AT 12Z, AND THE VORTICITY MAX WILL LIKELY BE STRONG ENOUGH TO BRING A QUICK BURST OF SNOW TO BUTLER, CLINTON, AND SEDALIA LATE THIS AFTERNOON AND EARLY THIS EVENING. THE SPRINGFIELD SOUNDING FROM THIS MORNING SHOWED A SIGNIFICANT DRY MID LAYER, BUT MOISTURE WILL BE ADVECTED QUICKLY NORTH FROM EAST TEXAS THIS AFTERNOON. EVAPORATIVE COOLING WILL BE SUFFICIENT TO CAUSE PRECIPITATION TO BE SNOW TO THE CITIES LISTED ABOVE. I AM EXPECTING A WINDOW OF 3 OR 4 HOURS WITH THIS QUICK MOVING VORT MAX, SO SNOW AMOUNTS WILL BE LESS THAN AN INCH. KOCH .AVIATION DISCUSSION... 1130 AM... STRONG SHORTWAVE CURRENTLY CENTERED ALONG THE KS/OK BORDER AROUND DDC WILL QUICKLY MOVE EAST ACROSS SOUTHERN MISSOURI THIS EVENING. MOISTURE LACKING FOR ANY FROZEN PRECIPITATION FOR THE KC/STJ TERMINAL LOCATIONS. PRECIPITATION SHOULD REMAIN TO THE SOUTH AND EAST. MAIN CONCERN IS THE DEVELOPMENT/ADVECTION OF LOW CLOUD DECK CURRENTLY PREVAILING ACROSS NORTHCENTRAL KANSAS AND SE NEBRASKA. LOW CLOUD DECK WAS IN THE VICINITY OF SURFACE TROUGH/COLD FRONT IN SE NEBRASKA. AS THE SHORTWAVE PROGRESSES EAST LATE THIS AFTERNOON...THE FRONT WILL DROP INTO NW MISSOURI LATE THIS AFTERNOON. MESOETA GRIDS CONFIRM THAT LOW CLOUD DECK WILL DROP SE WITH THE SURFACE TROUGH. HAVE INTRODUCED IFR CIGS AND MVFR VSBYS FOR LATE THIS AFTERNOON WITH CIGS DROPPING TO AROUND LIFR STATUS THIS EVENING. WITH ONLY WEAK SUBSIDENCE AND WINDS IN THE 925-SFC LAYER...LOW CLOUDS WILL LINGER THROUGH THE ENTIRE NIGHT...LONGER THAN THE MESOETA MODEL SUGGEST. CURRENTLY HAVE LOW CLOUD DECK CLEARING BY 12Z SATURDAY...HOWEVER...HAVE SOME CONCERN THAT THE LOW CLOUD DECK COULD LINGER THROUGH MUCH OF THE MORNING WITH ONLY WEAK SOLAR INSOLATION AND BOUNDARY LAYER FLOW SWITCHING BACK TO THE SOUTH. DB && .PREVIOUS DISCUSSION... 351 AM MAIN CONCERN IS TEMPS THROUGH THE NEXT FEW DAYS. EXPECT STRATOCU TO PERSIST ACROSS THE AREA THROUGH MUCH OF TODAY WITH WEAK ISENTROPIC LIFT CONTINUING AHEAD OF A WEAK SHORTWAVE MOVING ACROSS THE REGION. MAY EVEN SEE SOME MORE SCATTERED FLURRIES ASSOCIATED WITH THIS LIFT AS WELL. BEST CHANCE TO SEE FLURRIES IS IN THE NORTHWEST CORNER OF MISSOURI...CLOSEST TO THE SHORTWAVE. ONCE AGAIN EXPECT THE CLOUDS TO BE ON THE DECREASE THIS EVENING AND OVERNIGHT...GIVING ANOTHER CHILLY NIGHT WITH TEMPS FALLING INTO THE TEENS TO AROUND 20 DEGREES. MAY ALSO SEE SOME PATCHY FOG BUT WILL PROBABLY HAVE TO WAIT ON THAT UNTIL THE RIDGE MOVES EAST. HIGH PRESSURE IS QUITE OFTEN SLOW TO MOVE EAST SO LOWERED HIGHS ON SATURDAY TO SEVERAL DEGREES BELOW GUIDANCE...TO ACCOUNT FOR VERY LITTLE MIXING AND A RELATIVELY COOL START. HIGH MOVES EAST BY SATURDAY NIGHT...SETTING UP RETURNING MOISTURE AND A MUCH BETTER CHANCE FOR AREAS OF FOG. HAVE JUST A SMALL CHANGE IN TEMPS FROM SATURDAY HIGHS TO LOWS SUNDAY MORNING. THE WARMER TEMPS WILL GENERALLY CONTINUE THROUGH TUESDAY. ALTHOUGH THE ETA IS SHOWING A COLD FRONT MOVING ACROSS THE REGION SUNDAY NIGHT INTO MONDAY...WHICH WILL HAVE TO BE WATCHED. DIFFERENCE BETWEEN ETA AND GFS HIGHS ON MONDAY IS ABOUT 25 DEGREES. SO LEFT HIGHS WHERE THEY WERE...GOING COOLER THAN GFS AND WARMER THAN ETA. BUT IF GFS COMES IN CLOSER TO THE ETA...HIGHS TEMPS WILL HAVE TO BE LOWERED SIGNIFICANTLY ON MONDAY. NRR && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo