AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL...CORRECTED HEADER 835 PM CDT TUE APR 6 2004 .DISCUSSION... 01Z SFC CHART SHOWING WEAK FRONT NEAR A CHI/PIA TO JUST NORTH OF KIRK MO LINE. BOUNDARY IS WEAK BUT DOES HAVE QUITE A BIT DRIER AIR BEHIND IT. FRONT IS EXPECTED TO OOZE ON INTO THE CWA DURING THE NIGHT WITH LITTLE FAN-FARE. THINK BOUNDARY WILL MAKE IT TO NEAR THE I-70 CORRIDOR BY MORNING, POSSIBLY AS FAR SOUTH AS BETWEEN I-70 AND I-64, THEN BECOME STATIONARY. RADARS ARE QUIET THIS EVENING. KILX SOUNDING INDICATES THAT THE LOW LEVELS ARE TOO DRY TO SUPPORT MUCH IN THE WAY OF PRECIP. MAYBE A SPRINKLE WOULD BE ABOUT IT. OVERALL THE ZONES LOOK PRETTY GOOD THIS EVENING. WILL ISSUE AN UPDATE THOUGH...MAINLY TO REMOVE MENTION OF EVENING POPS. AM HESITANT TO REMOVE SLIGHT CHANCE POP ACROSS THE SOUTH THOUGH DUE TO THE BOUNDARY. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH SATURDAY WATER VAPOR IMAGERY SHOWING UPPER VORT SLIDING THROUGH NORTHERN WISCONSIN WITH LOW LEVEL BOUNDARY ACROSS SOUTHERN WISCONSIN/NORTHERN ILLINOIS EXPECTED TO CONTINUE TO SAG SOUTH DURING THE EARLY EVENING HOURS. LOW LEVEL MOISTURE PROFILE RATHER DRY EVIDENT IN 12Z RAOBS FROM KDVN AND ILK AND ALSO FROM RUC PROGS THROUGH THIS EVENING. HOWEVER...WITH WEAK LOW MID LEVEL FRONTOGENESIS AXIS PROGRESSING THROUGH CENTRAL ILLINOIS WILL MAINTAIN SOME LOW POPS FOR ISOLATED SHOWERS TONIGHT. AFTER MIDNIGHT...ANY REMAINING ISOLATED SHOWER ACTIVITY SHOULD BE CONFINED TO FAR SOUTHERN CWA AS LOW LEVEL BAROCLINIC ZONE SHOULD HANG UP SOMEWHERE ACROSS SOUTHERN HALF OF CWA. OTHERWISE PARTLY CLOUDY SKIES ARE EXPECTED TONIGHT WITH PERHAPS A TREND TO MOSTLY CLEAR AS MODEL TIME/HEIGHT SECTIONS SHOW SOME GOOD MID LEVEL DRYING AFTER 06Z. ON WEDNESDAY...NEXT WAVE IN NORTHWEST FLOW WILL TRACK INTO NORTHERN HALF OF MINNESOTA DURING THE AFTERNOON ALLOWING FOR LOW LEVEL THERMAL RIDGE TO REAMPLIFY DURING THE AFTERNOON. HIGHER AMOUNTS OF SOLAR INSOLATION ON WEDNESDAY SHOULD PARTIALLY OFFSET SLIGHTLY COOLER LOW LEVELS TO GIVE MAX TEMPS SIMILAR TO THAT OF TODAY. CONCERN WILL THEN BE FRONTAL PASSAGE FOR WEDNESDAY NIGHT/THURSDAY MORNING AS MINNESOTA VORT TRACKS EAST. 80 KNOT UPPER JET ALSO PROGGED TO PROGRESS THROUGH BASE OF THIS TROUGH HELPING TO ENHANCE UPPER DIVERGENCE FOR WEDNESDAY NIGHT. INFLUENCE OF SOUTHERN STREAM WILL KEEP CHANCE POPS GOING WEDNESDAY NIGHT INTO THURSDAY MORNING WITH SOME DECENT UPPER LEVEL CYCLONIC CURVATURE WITH THIS WAVE. MODELS AGREE IN PROGRESSIVE NATURE OF THIS SHORT WAVE SO WILL END POPS BY 18Z THURSDAY. 12Z GFS CONTINUES IDEA OF DIGGING SHORT WAVE TROUGH THROUGH CENTRAL ROCKIES REINFORCING EASTERN CONUS LONGWAVE TROUGH FOR FRIDAY. THUS...EXPECTING ACTIVE PATTERN OF SHORT WAVES THROUGH THE REGION FRIDAY NIGHT INTO SATURDAY AND WILL CONTINUE CHANCE OF LIGHT RAIN FOR THIS PERIOD. .LONG TERM...SUNDAY THROUGH TUESDAY DRY CONDITIONS EXPECTED FOR SUNDAY WITH COLD ADVECTION IN WAKE OF SHORT WAVE AND SHOULD SEE SOME GOOD LOW LEVEL DRYING. NEXT CONCERN WILL BE MORE POTENT WAVE ROTATING AROUND BROAD LONGWAVE TROUGH FOR FIRST PART OF NEXT WEEK. ECMWF/GFS IN GENERAL AGREEMENT WITH MAIN UPPER FORCING STAYING SOUTH OF CWA...BUT PATTERN DOES SEEM CONDUCIVE FOR SOME FRONTAL PRECIP...ESPECIALLY ACROSS EASTERN PORTIONS OF CWA. WENT WITH TEMPS COOLER THAN MEX GUIDANCE THROUGHOUT THE EXTENDED PORTION OF FORECAST WITH BROAD NEGATIVE HEIGHT ANOMALY IN PLACE. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...NONE. && $$ HALL il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL ISSUED BY NWS CHICAGO 835 PM CDT TUE APR 6 2004 .DISCUSSION... 01Z SFC CHART SHOWING WEAK FRONT NEAR A CHI/PIA TO JUST NORTH OF KIRK MO LINE. BOUNDARY IS WEAK BUT DOES HAVE QUITE A BIT DRIER AIR BEHIND IT. FRONT IS EXPECTED TO OOZE ON INTO THE CWA DURING THE NIGHT WITH LITTLE FAN-FARE. THINK BOUNDARY WILL MAKE IT TO NEAR THE I-70 CORRIDOR BY MORNING, POSSIBLY AS FAR SOUTH AS BETWEEN I-70 AND I-64, THEN BECOME STATIONARY. RADARS ARE QUIET THIS EVENING. KILX SOUNDING INDICATES THAT THE LOW LEVELS ARE TOO DRY TO SUPPORT MUCH IN THE WAY OF PRECIP. MAYBE A SPRINKLE WOULD BE ABOUT IT. OVERALL THE ZONES LOOK PRETTY GOOD THIS EVENING. WILL ISSUE AN UPDATE THOUGH...MAINLY TO REMOVE MENTION OF EVENING POPS. AM HESITANT TO REMOVE SLIGHT CHANCE POP ACROSS THE SOUTH THOUGH DUE TO THE BOUNDARY. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH SATURDAY WATER VAPOR IMAGERY SHOWING UPPER VORT SLIDING THROUGH NORTHERN WISCONSIN WITH LOW LEVEL BOUNDARY ACROSS SOUTHERN WISCONSIN/NORTHERN ILLINOIS EXPECTED TO CONTINUE TO SAG SOUTH DURING THE EARLY EVENING HOURS. LOW LEVEL MOISTURE PROFILE RATHER DRY EVIDENT IN 12Z RAOBS FROM KDVN AND ILK AND ALSO FROM RUC PROGS THROUGH THIS EVENING. HOWEVER...WITH WEAK LOW MID LEVEL FRONTOGENESIS AXIS PROGRESSING THROUGH CENTRAL ILLINOIS WILL MAINTAIN SOME LOW POPS FOR ISOLATED SHOWERS TONIGHT. AFTER MIDNIGHT...ANY REMAINING ISOLATED SHOWER ACTIVITY SHOULD BE CONFINED TO FAR SOUTHERN CWA AS LOW LEVEL BAROCLINIC ZONE SHOULD HANG UP SOMEWHERE ACROSS SOUTHERN HALF OF CWA. OTHERWISE PARTLY CLOUDY SKIES ARE EXPECTED TONIGHT WITH PERHAPS A TREND TO MOSTLY CLEAR AS MODEL TIME/HEIGHT SECTIONS SHOW SOME GOOD MID LEVEL DRYING AFTER 06Z. ON WEDNESDAY...NEXT WAVE IN NORTHWEST FLOW WILL TRACK INTO NORTHERN HALF OF MINNESOTA DURING THE AFTERNOON ALLOWING FOR LOW LEVEL THERMAL RIDGE TO REAMPLIFY DURING THE AFTERNOON. HIGHER AMOUNTS OF SOLAR INSOLATION ON WEDNESDAY SHOULD PARTIALLY OFFSET SLIGHTLY COOLER LOW LEVELS TO GIVE MAX TEMPS SIMILAR TO THAT OF TODAY. CONCERN WILL THEN BE FRONTAL PASSAGE FOR WEDNESDAY NIGHT/THURSDAY MORNING AS MINNESOTA VORT TRACKS EAST. 80 KNOT UPPER JET ALSO PROGGED TO PROGRESS THROUGH BASE OF THIS TROUGH HELPING TO ENHANCE UPPER DIVERGENCE FOR WEDNESDAY NIGHT. INFLUENCE OF SOUTHERN STREAM WILL KEEP CHANCE POPS GOING WEDNESDAY NIGHT INTO THURSDAY MORNING WITH SOME DECENT UPPER LEVEL CYCLONIC CURVATURE WITH THIS WAVE. MODELS AGREE IN PROGRESSIVE NATURE OF THIS SHORT WAVE SO WILL END POPS BY 18Z THURSDAY. 12Z GFS CONTINUES IDEA OF DIGGING SHORT WAVE TROUGH THROUGH CENTRAL ROCKIES REINFORCING EASTERN CONUS LONGWAVE TROUGH FOR FRIDAY. THUS...EXPECTING ACTIVE PATTERN OF SHORT WAVES THROUGH THE REGION FRIDAY NIGHT INTO SATURDAY AND WILL CONTINUE CHANCE OF LIGHT RAIN FOR THIS PERIOD. .LONG TERM...SUNDAY THROUGH TUESDAY DRY CONDITIONS EXPECTED FOR SUNDAY WITH COLD ADVECTION IN WAKE OF SHORT WAVE AND SHOULD SEE SOME GOOD LOW LEVEL DRYING. NEXT CONCERN WILL BE MORE POTENT WAVE ROTATING AROUND BROAD LONGWAVE TROUGH FOR FIRST PART OF NEXT WEEK. ECMWF/GFS IN GENERAL AGREEMENT WITH MAIN UPPER FORCING STAYING SOUTH OF CWA...BUT PATTERN DOES SEEM CONDUCIVE FOR SOME FRONTAL PRECIP...ESPECIALLY ACROSS EASTERN PORTIONS OF CWA. WENT WITH TEMPS COOLER THAN MEX GUIDANCE THROUGHOUT THE EXTENDED PORTION OF FORECAST WITH BROAD NEGATIVE HEIGHT ANOMALY IN PLACE. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...NONE. && $$ HALL il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 935 PM EST TUE APR 6 2004 .UPDATE... UPDATED GRIDS/FORECAST TO REMOVE SHOWERS AND JUST GO WITH SPRINKLES. RADAR IS CURRENTLY QUIET. LOWER LEVELS OF ATMS ARE DRY...AND BEST ISENTROPIC LIFT SHOULD DECREASE/MOVE EAST OF FORECAST AREA TONIGHT. THUS FELT SPRINKLES SHOULD COVER ANY PRECIP...AND RUC/00Z ETA AGREE. && .PREV DISCUSSION... MAIN FORECAST CONCERNS WILL BE TIMING OF VARIOUS S/W AND ASSOCIATED PRECIP CHANCES NEXT FEW DAYS AS WE REMAIN UNDER A RELATIVELY FAST AND SOMEWHAT ZONE FLOW. RADAR IS CURENTLY SHOWING SOME LIGHT SHOWERS ACROSS IL IN AN AREA OF ISENTROPIC LIFT. THE COLD FRONT FORECAST TO CROSS THE STATE OVERNIGHT IS STILL IN WI AND IA BUT PROGRESSING SEWD. DEWPOINTS THIS AFTERNOON ARE STILL IN THE LOW 30'S. WITH LITTLE PRECIP AHEAD OF THE FRONT...WILL KEEP ONLY 20% POPS TONIGHT WITH INCREASED CLOUDS. MODELS ARE IN GENERAL OVERALL AGREEMENT FOR WED AND THURSDAY. TONIGHTS WEAK COLD FRONT STALLS NEAR THE OHIO RIVER. A COUPLE OF S/W MOVING BY BRING CHANCE OF SHOWERS ACROSS OUR SOUTHERN AREAS WEDNESDAY AND REGION WIDE WEDNESDAY NIGHT AND THURSDAY. ALL MODELS NOW INDICATE PRECIP SHOULD BE OUT OF HERE BY THURSDAY AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 850 PM EST TUE APR 6 2004 .UPDATE... QUICK UPDATE THIS EVENING TO FRESHEN ZFP WORDING BY REMOVING EARLY EVENING POPS. DECIDED TO LEAVE SOME SPRINKLES IN SOUTHERN COUNTIES UNTIL FRONT COMPLETELY CLEARS THAT AREA. STILL SOME CLOUDS SEEN ON SATELLITE WITH THIS FRONT AND RUC40 GENERATING SOME DECENT 850MB OMEGA BEFORE 06Z. HOWEVER...LOWER LEVELS QUITE DRY AND WITHOUT SIGNIFICANT FORCING JUST DO NOT SEE MUCH IN THE WAY OF MEASURABLE PCPN OCCURING. DECIDED TO RAISE MAX TEMPS FOR WED BASED ON OBJECTIVE GUIDANCE TRENDS LAST SEVERAL RUNS AND UPSTREAM TEMPERATURES BEHIND COLD FRONT TODAY. EXPERIMENTAL WAM NUMBERS ALSO SUPPORTING WARMER TEMPERATURES. BIGGEST CHANGE WAS TO CONFINE LAKE EFFECTS ON TEMPERATURE CLOSER TO LAKE MICHIGAN. LOW LEVEL WINDS SHOULD BE MORE NORTHEAST AND LIGHT BUT STILL EXPECT A LAKE BREEZE TO DEVELOP...JUST NOT MOVE INLAND AS MUCH AS PREVIOUS GRIDS INDICATED. THUS SBN TEMPERATURE WILL BE WARMER. && .AVIATION... LINE OF WEAK...PRE-FRONTAL SHOWERS HAVE PUSHED THROUGH TAF SITES. STILL A SLIGHT CHANCE FOR ADDITIONAL DEVELOPMENT ALONG ACTUAL SURFACE FRONT BUT COVERAGE AND INTENSITY NOT EXPECTED TO BE ENOUGH TO IMPACT VIS OR CIGS. WILL HAVE VFR CONDITIONS THROUGH ENTIRE PERIOD. BROKEN ALTOCUMULUS CIGS THIS EVENING WILL BECOME SCT. ONLY SOME HIGH BASED SCT CU EXPECTED WED WITH LIGHT NORTHEAST WINDS UNDER 10 KTS. && .PREV DISCUSSION... SHORT TERM... A WEAK COLD FRONT WILL BE MOVING THROUGH THE AREA LATE THIS AFTERNOON/EVENING. A FEW RAIN SHOWERS ARE ASSOCIATED WITH THE FRONT WHICH ARE CURRENTLY MOVING SOUTHEASTWARD THROUGH OUR MICHIGAN COUNTIES. NOT EXPECTING MUCH RAIN FROM THIS FRONT. NOT VERY MANY CLOUDS CURRENTLY IN NORTHERN ILLINOIS...MOST OF THE CLOUDS ARE OVER LAKE MICHIGAN AND SOUTHERN MICHIGAN. JUST KEPT THE LOW CHANCE POPS WITH THE FRONTAL PASSAGE. AFTER FRONTAL PASSAGE...THE RAIN CHANCES WILL END AS DRIER AIR IS BEHIND THE FRONT. ALSO WINDS TONIGHT WILL TURN TO THE NORTH AND THEN TO THE NORTHEAST TOMORROW MORNING. 12Z TOMORROW MORNING THE MODELS HAVE THE FRONT OVER SOUTHERN INDIANA AND THEN DURING THE DAY MOVE IT SOUTH OF THE STATE AS HIGH PRESSURE MOVES IN. TEMPERATURES WILL DROP TO AROUND 40 ACROSS OUR CWA AND THEN RISE TO AROUND 60 TOMORROW...EXCEPT AREAS NEAR LAKE MICHIGAN WILL BE COOLER. LONG TERM... WEDNESDAY NIGHT THROUGH NEXT TUESDAY...OVERALL...EXPECT A COOL AND GENERALLY DRY PATTERN TO DOMINATE THE PERIOD. WILL KEEP A CHANCE FOR SHOWERS IN LATE WEDNESDAY NIGHT AND THURSDAY AS ANOTHER COOL FRONT PASSES...BUT ONCE AGAIN WITH MOISTURE LIMITED AND A WEAK FRONT...DO NOT EXPECT MUCH RAIN. AFTER THURSDAY...HAVE KEPT THE FORECAST DRY AND COOL WITH TEMPS BELOW NORMAL. GFS OF RECENT HAS HAD POOR RUN TO RUN CONSISTENCY WHICH IS APPARENT IN MEX MOS FLUCTUATIONS IN BOTH TEMPS AND POPS. BUT BASIC UPPER AIR PATTERN OF A DEVELOPING TROF OVER THE CENTRAL CONUS BY EARLY NEXT WEEK ALONG WITH A STRONG SFC RIDGE OVER CENTRAL CANADA IS PREEMINENT. EARLIER RUNS OF THE GFS WAS SUGGESTING A SURFACE WAVE WOULD SPREAD AT LEAST SOME PRECIPITATION OVER THE SOUTHERN PART OF THE AREA THIS WEEKEND...BUT GIVEN DOMINANT NORTH TO NORTHEAST SFC FLOW AND RUN TO RUN INCONSISTENCIES OF THE GFS AND ALSO TREND OF THE GFS TO OVER FORECAST PRECIPITATION IN THE NORTHERN PART OF STORM SYSTEM WHEN THERE IS A LOT OF DRY AIR ADVECTING IN THE LOWER LAYERS...HAVE KEEP THE FORECAST DRY. 12Z GFS SHOWED VERY COOL TEMPS SATURDAY THROUGH TUESDAY OF -4C OR COLDER AT 850 MB. HAVE HIGH BASICALLY 45 TO 50 THROUGH THE PERIOD TO MATCH THESE COOL TEMPS. 12Z GFS EXTENDED WAS EVEN SLOWER WITH MAJOR TROF EJECTING OUT OF THE PLAINS EARLY NEXT WEEK. GFS RUN FROM LAST NIGHT WAS BRINGING PRECIPITATION IN MONDAY...BUT NEW 12Z RUN WAS DRY THROUGH TUESDAY. GIVEN TENDENCY FOR GFS TO BE TOO FAST WITH HIGHLY AMPLIFIED SYSTEMS HAVE OPTED TO KEEP TUESDAY DRY AS THIS REASONING SUGGESTS BEST CHANCE OF RAIN WOULD BE AFTER TUESDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. && $$ LASHLEY/BML/SKIP in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 949 PM CDT TUE APR 6 2004 .DISCUSSION... UPPER LOW OVER THE TEXAS PANHANDLE THIS EVENING...WITH A VORT MAX OVER NORTH CENTRAL TEXAS AND MCS OVER SOUTHERN LA. STORMS IN THE DALLAS AREA ARE DECREASING WITH THE LOST OF HEATING OF THE DAY...HOWEVER RUC AND NEW ETA...HINT AT SOME DEVELOPMENT OVER NORTHEAST TX LATER AND THEN SPREADING EAST. THEREFORE DID NOT CHANGE RAIN CHANCES NORTHWEST...BUT LOWERED RAIN CHANCES GENERALLY EAST OF A LINE FROM LFK TO ELD. ADJUSTED TEMPS IN A FEW LOCATIONS. ADDED FOG TO NORTHEAST TX AND EXTREME WESTERN LOUISIANA...WHERE RAIN FELL EARLIER TODAY. UPDATE ALREADY OUT. UPDATED GRIDS OUT SHORTLY. IV && .PRELIMINARY POINT TEMPS/POPS... SHV 54 74 56 77 / 40 50 30 0 MLU 52 74 57 77 / 20 50 30 0 TXK 52 72 56 75 / 40 60 30 0 TYR 55 74 56 77 / 40 30 30 0 LFK 55 79 59 80 / 20 30 30 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 850 PM EDT TUE APR 6 2004 .UPDATE... FORECAST ON TARGET TONIGHT. MAIN CONCERN IS THE THREAT OF LOWER CLOUDS. 18Z ETA LIKE THE 12Z RUN WITH PLENTY OF 925 MOISTURE ACROSS THE CWA. HOWEVER...CURRENT OBS DO NOT SUPPORT THIS...AND 21Z RUC MUCH MORE IN LINE WITH CURRENT SITUATION WITH ONLY APN AND SSM REPORTING THE LOWER CLOUDS. THEREFORE...THE CLOUDS ASSOCIATED WITH THE WEAK SHORTWAVE AND SURFACE LOW WILL MOVE OUT OF SOUTHEAST LOWER MICHIGAN BY AROUND 03Z. WILL KEEP SKIES MOSTLY CLOUDY ACROSS THE THUMB AS THIS WILL BE THE MOSTLY LIKELY SPOT FOR THE LOWER CLOUDS TO RETURN. PLUS WINDS WILL TURN TO THE NORTH NORTHWEST WHICH SHOULD AID SC DEVELOPMENT. WINDS HAVE BEEN A LITTLE SLOW TO TURN TO THE WEST AND NORTHWEST...SO WILL HAVE TO TIME THE WINDS IN THE FORECAST A LITTLE SLOWER TOO. TEMPS HAVE BEEN RUNNING A BIT WARMER. BUT WITH PARTLY CLOUDY SKIES...WINDS BECOMING LIGHTER AND DEW POINTS GENERALLY IN THE MID AND UPPER 30S...EXPECT TEMPS TO REACH FORECAST LOW TEMPS...SO NO CHANGES THERE. RBP && .PREV DISCUSSION... A COUPLE OF ISSUES HERE TO RESOLVE...JUST ABOUT ALL OF THEM MINOR. DESPITE SOME IMPRESSIVE RETURNS ON KGRR RADAR...CEILINGS AT 7K FEET TELL THE STORY WITH ONLY SPRINKLES HITTING THE GROUND TO OUR WEST. THIS ACTIVITY OCCURRING IN AREA OF ENHANCED THETA-E ADVECTION. BEST ADVECTION WILL BE CONFINED TO THE SOUTH HALF OF THE CWA THROUGH ABOUT 00Z THEN SLIDE EAST TAKING PRECIP OUT OF THE AREA. WILL CARRY SCT -SHRA THROUGH THE EARLY EVENING...MAINLY SOUTH...OTHERWISE DRY. OTHER ISSUE WILL BE WITH CLOUDS. MESOETA IS FAIRLY AGGRESSIVE IN BRINGING LOW CLOUDS DOWN ACROSS MUCH OF THE CWA AS LOW PASSES TO OUR EAST AND COLD FRONT DROPS IN BEHIND THE LOW. CURRENTLY MESOETA IS OVERDONE ON RH FIELD...PARTICULARLY ACROSS NW LOWER MICHIGAN. NGM AND RUC SUGGEST BULK OF LOW LEVEL MOISTURE WILL PASS TO OUR EAST. WILL CARRY MOSTLY CLOUDY FOR THUMB TONIGHT AND PARTLY CLOUDY ELSEWHERE. EXPECT WHATEVER CLOUDS ARE AROUND WEDNESDAY MORNING TO GIVE WAY TO PARTLY/MOSTLY SUNNY SKIES FOR AFTERNOON. MAX TEMPS A LITTLE TRICKY. TEMPERATURES IN WI WARMING NICELY THIS AFTERNOON WITH READINGS INTO THE 60S...AND LIKELY TO HIT 70 BEFORE THE DAY IS DONE. HOWEVER...A COUPLE OF FACTORS TO CONSPIRE TO HOLD TEMPS DOWN HERE TOMORROW...850MB TEMPS SOME 3-5C LOWER THAN WI...HIGH OVERHEAD LIKELY TO LIMIT MIXING...AND FINALLY LIGHT 950MB WINDS SHOULD PROMOTE DEVELOPMENT OF AT LEAST A WEAK LAKE BREEZE. NEXT ISSUE WILL BE PRECIP CHANCES ON THURSDAY. MODELS HAVE SLOWED SYSTEM SOME...ENOUGH TO REMOVE LIGHT PRECIP CHANCES FOR NW CWA WEDNESDAY NIGHT. ETA LOOKS TO BE THE MORE CONSISTENT OF THE MODELS IN TERMS OF STORM TRACK AND LIFT. WITH THIS THOUGHT IN MIND...WILL LEAN TOWARD ETA SOLUTION. LIMITING FACTOR AS FAR AS PRECIP IS CONCERNED PER ETA...IS LIMITED MOISTURE WITH LOW PUSHING THROUGH CWA. PLAN TO CONTINUE WITH CHANCE POPS. WILL CARRY CHANCE OF SHRA-BOTH ETA AND GFS THICKNESSES WOULD SUPPORT RAIN. AS LOW PULLS OUT...ETA WANTS TO SWING UPPER LEVEL CUTOFF ACROSS THE REGION...WHILE GFS STREAMS A RIBBON OF CHANNELED VORTICITY ACROSS CWA. WILL LINGER THURSDAY PRECIP INTO THURSDAY EVENING...THEN HOLD DRY. EXTENDED... WILL THERE BE SNOWFLAKES ON YOUR EASTER BONNET. THAT AMONG OTHER ITEMS CONFRONTS US HERE. MODELS IN GOOD AGREEMENT IN EVOLVING LONG WAVE TROUGH TO THE WEST OF US DURING THE PERIOD...WITH GFS CUTTING OFF SYSTEM INTO UPPER LOW ACROSS THE UPPER MIDWEST LATE IN THE PERIOD. DOMINATING FEATURE THROUGH THE EXTENDED WILL BE STRONG ARCTIC HIGH PRESSURE THAT WILL CROSS CANADA...PROVIDING CWA WITH DRY NORTHEAST FLOW. COLD AIR WILL FILTER INTO THE CWA AS THE HIGH SWINGS THROUGH CANADA...WITH 850MB TEMPS DROPPING TO -8C SUNDAY /EASTER/ MORNING. CLIMO IS AROUND 1C. GFS HAS HAD DIFFICULTY RESOLVING PRECIP CHANCES ACROSS CWA...WITH CURRENT GFS/CANADIAN PRECIP ENSEMBLES OFFERING LITTLE SUPPORT FOR PRECIP ON SUNDAY. WILL KEEP SUNDAY DRY...BUT NOTE...THAT IF GFS WERE TO VERIFY...SOME SNOWFLAKES COULD FLY ON EASTER. MOVING INTO MONDAY-TUESDAY PERIOD...STILL DIFFERENCES IN MODELS...AND AMONG MODELS. GFS PUSHES POTENT SURFACE LOW RIGHT THROUGH CWA /YESTERDAY/S GFS HAD LOW NEAR BOSTON...LATEST 12Z GFS NOW PROMOTING EAST COAST LOW-STAY TUNED./...WHILE ETA-XX BY EXTRAPOLATION ARGUES FOR A SOLUTION MORE IN LINE WITH YESTERDAY/S GFS. GFS PRECIP ENSEMBLES DO POINT TO AT LEAST CHANCE POPS FOR MONDAY INTO TUESDAY. WITH THIS IN MIND WILL CALL FOR CHANCE RAIN/SNOW MONDAY...THEN ALL RAIN MONDAY NIGHT AND TUESDAY. WITH CONSIDERABLE UNCERTAINTY STILL IN THE PICTURE...WILL HOLD TO ONLY CHANCE POPS. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ OKEEFE EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 650 PM EDT TUE APR 6 2004 .UPDATE... QUICK UPDATE NOW THAT THE SHOWERS HAVE MOVED OUT OF SOUTHEAST MICHIGAN. JUST NEED TO UPDATE THE WORDING. RBP && .PREV DISCUSSION... A COUPLE OF ISSUES HERE TO RESOLVE...JUST ABOUT ALL OF THEM MINOR. DESPITE SOME IMPRESSIVE RETURNS ON KGRR RADAR...CEILINGS AT 7K FEET TELL THE STORY WITH ONLY SPRINKLES HITTING THE GROUND TO OUR WEST. THIS ACTIVITY OCCURRING IN AREA OF ENHANCED THETA-E ADVECTION. BEST ADVECTION WILL BE CONFINED TO THE SOUTH HALF OF THE CWA THROUGH ABOUT 00Z THEN SLIDE EAST TAKING PRECIP OUT OF THE AREA. WILL CARRY SCT -SHRA THROUGH THE EARLY EVENING...MAINLY SOUTH...OTHERWISE DRY. OTHER ISSUE WILL BE WITH CLOUDS. MESOETA IS FAIRLY AGGRESSIVE IN BRINGING LOW CLOUDS DOWN ACROSS MUCH OF THE CWA AS LOW PASSES TO OUR EAST AND COLD FRONT DROPS IN BEHIND THE LOW. CURRENTLY MESOETA IS OVERDONE ON RH FIELD...PARTICULARLY ACROSS NW LOWER MICHIGAN. NGM AND RUC SUGGEST BULK OF LOW LEVEL MOISTURE WILL PASS TO OUR EAST. WILL CARRY MOSTLY CLOUDY FOR THUMB TONIGHT AND PARTLY CLOUDY ELSEWHERE. EXPECT WHATEVER CLOUDS ARE AROUND WEDNESDAY MORNING TO GIVE WAY TO PARTLY/MOSTLY SUNNY SKIES FOR AFTERNOON. MAX TEMPS A LITTLE TRICKY. TEMPERATURES IN WI WARMING NICELY THIS AFTERNOON WITH READINGS INTO THE 60S...AND LIKELY TO HIT 70 BEFORE THE DAY IS DONE. HOWEVER...A COUPLE OF FACTORS TO CONSPIRE TO HOLD TEMPS DOWN HERE TOMORROW...850MB TEMPS SOME 3-5C LOWER THAN WI...HIGH OVERHEAD LIKELY TO LIMIT MIXING...AND FINALLY LIGHT 950MB WINDS SHOULD PROMOTE DEVELOPMENT OF AT LEAST A WEAK LAKE BREEZE. NEXT ISSUE WILL BE PRECIP CHANCES ON THURSDAY. MODELS HAVE SLOWED SYSTEM SOME...ENOUGH TO REMOVE LIGHT PRECIP CHANCES FOR NW CWA WEDNESDAY NIGHT. ETA LOOKS TO BE THE MORE CONSISTENT OF THE MODELS IN TERMS OF STORM TRACK AND LIFT. WITH THIS THOUGHT IN MIND...WILL LEAN TOWARD ETA SOLUTION. LIMITING FACTOR AS FAR AS PRECIP IS CONCERNED PER ETA...IS LIMITED MOISTURE WITH LOW PUSHING THROUGH CWA. PLAN TO CONTINUE WITH CHANCE POPS. WILL CARRY CHANCE OF SHRA-BOTH ETA AND GFS THICKNESSES WOULD SUPPORT RAIN. AS LOW PULLS OUT...ETA WANTS TO SWING UPPER LEVEL CUTOFF ACROSS THE REGION...WHILE GFS STREAMS A RIBBON OF CHANNELED VORTICITY ACROSS CWA. WILL LINGER THURSDAY PRECIP INTO THURSDAY EVENING...THEN HOLD DRY. EXTENDED... WILL THERE BE SNOWFLAKES ON YOUR EASTER BONNET. THAT AMONG OTHER ITEMS CONFRONTS US HERE. MODELS IN GOOD AGREEMENT IN EVOLVING LONG WAVE TROUGH TO THE WEST OF US DURING THE PERIOD...WITH GFS CUTTING OFF SYSTEM INTO UPPER LOW ACROSS THE UPPER MIDWEST LATE IN THE PERIOD. DOMINATING FEATURE THROUGH THE EXTENDED WILL BE STRONG ARCTIC HIGH PRESSURE THAT WILL CROSS CANADA...PROVIDING CWA WITH DRY NORTHEAST FLOW. COLD AIR WILL FILTER INTO THE CWA AS THE HIGH SWINGS THROUGH CANADA...WITH 850MB TEMPS DROPPING TO -8C SUNDAY /EASTER/ MORNING. CLIMO IS AROUND 1C. GFS HAS HAD DIFFICULTY RESOLVING PRECIP CHANCES ACROSS CWA...WITH CURRENT GFS/CANADIAN PRECIP ENSEMBLES OFFERING LITTLE SUPPORT FOR PRECIP ON SUNDAY. WILL KEEP SUNDAY DRY...BUT NOTE...THAT IF GFS WERE TO VERIFY...SOME SNOWFLAKES COULD FLY ON EASTER. MOVING INTO MONDAY-TUESDAY PERIOD...STILL DIFFERENCES IN MODELS...AND AMONG MODELS. GFS PUSHES POTENT SURFACE LOW RIGHT THROUGH CWA /YESTERDAY/S GFS HAD LOW NEAR BOSTON...LATEST 12Z GFS NOW PROMOTING EAST COAST LOW-STAY TUNED./...WHILE ETA-XX BY EXTRAPOLATION ARGUES FOR A SOLUTION MORE IN LINE WITH YESTERDAY/S GFS. GFS PRECIP ENSEMBLES DO POINT TO AT LEAST CHANCE POPS FOR MONDAY INTO TUESDAY. WITH THIS IN MIND WILL CALL FOR CHANCE RAIN/SNOW MONDAY...THEN ALL RAIN MONDAY NIGHT AND TUESDAY. WITH CONSIDERABLE UNCERTAINTY STILL IN THE PICTURE...WILL HOLD TO ONLY CHANCE POPS. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ OKEEFE EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI ISSUED BY NATIONAL WEATHER SERVICE MARQUETTE MI 330 PM EDT TUE APR 6 2004 .SHORT TERM (TNGT AND WED)... 18Z WATER VAPOR LOOP AND THE RUC 500MB HEIGHT ANALYSIS SHOWED NW FLOW EXTENDING FROM A RIDGE OVER WESTERN CANADA TO A TROUGH OVER THE CANADIAN MARITIMES. SHRTWV THAT BROUGHT RAIN TO LOWER MI THIS MORNING INTO EARLY THIS AFTERNOON NOW OVER LAKE MICHIGAN. VISIBLE SATELLITE IMAGERY SHOWED A BAND OF CLOUDS AHEAD OF THE SHRTWV EXTENDING FROM NORTHERN ONTARIO THROUGH EASTERN UPPER MICHIGAN AND EASTERN LOWER MI. THIS BAND HAS BEEN PROGRESSING SLOWLY EASTWARD AS THE SHRTWV MOVES CLOSER. ALSO ASSOCIATED WITH THE SHRTWV WAS A 1008 MB SURFACE LOW WHICH AT 18Z WAS LOCATED NEAR SAGINAW BAY. BEHIND THE SURFACE LOW AND IN SUNNY SKIES...TEMPERATURES HAVE WARMED NICELY WITH READINGS IN THE 60S OVER NORTHERN WI AND 50S IN WESTERN LOWER MI. PER SURFACE OBSERVATIONS...HIGH PRESSURE NOW BEGINNING TO BUILD INTO THE WESTERN GREAT LAKES FROM THE DAKOTAS. FURTHER TO THE WEST...ANOTHER SHRTWV WAS EVIDENT OVER CENTRAL ALBERTA. TONIGHT...AS THE SURFACE LOW AND SHRTWV CONTINUE TO HEAD TO THE SE IN NW FLOW ALOFT...EXPECTING SKIES TO CONTINUE TO SLOWLY CLEAR THIS EVENING. ETA/GFS THEN INDICATE THAT THE SURFACE HIGH OVER MN WILL MOVE OVER LOWER MI 09Z AND 12Z. WITH CURRENT DEWPOINTS ALREADY IN THE MID TO UPPER 30S...DRY AIR MOVING IN ALOFT AND LIGHT WINDS...WILL ADD A MENTION OF PATCHY FOG INTO THE FORECAST AS TEMPS FALL DOWN TO THE DEWPOINTS. WEDNESDAY...SHRTWV CURRENTLY IN ALBERTA MOVES TO THE FARGO AREA BY 12Z WED AND TO WESTERN LAKE SUPERIOR BY 00Z THU PER ETA/GFS. OVER LOWER MI HOWEVER...HIGH PRESSURE WILL BE FIRMLY IN CONTROL. SUNSHINE DURING THE MORNING WILL HELP MIX OUT ANY FOG THAT FORMED. THEN AS THE SHRTWV APPROACHES...EXPECTING HIGH CLOUDS TO INCREASE DURING THE AFTERNOON (SOME OF WHICH CAN ALREADY BE SEEN ON VISIBLE IMAGERY OVER THE DAKOTAS). NONETHELESS...WITH 850MB TEMPS PROGGED TO BE AROUND 1C AND SOME SUNSHINE DURING THE DAY...TEMPERATURES SHOULD CLIMB TO NEAR 50. AJ .LONG TERM... STRONG SHRTWV NOW OVER ALBERTA PROGGED TO MOVE ESE AND REACH THE UPR GREAT LKS LATE ON WED. ALTHOUGH SHRTWV CUTOFF FM ANY SGNFT MSTR INFLOW...AXIS OF HIER PWAT ABV 0.5 INCH IN SLY FLOW AHD OF THE SHRTWV/ACCOMPANYING SFC TROF FCST UNDER 12HR H5 HGT FALLS APRCHG 100M WED NGT. DESPITE VIGOROUS DYNAMICS...DRY AIR APPEARS TO WIN OUT WITH LLVL ELY FLOW AS ETA/GFS FCST SDNGS INDICATE DRY LYR UP TO H8 HANGING IN THRU 12Z. HAVE OPTED TO PUSH BACK ARRIVAL TIMING OF PCPN UNTIL CLOSE TO AFTER MIDNGT OVER THE NW PART OF THE CWA WHEN SOME UPR DVGC IN LEFT EXIT OF SUPPORTING H3 JET MAX/BETTER DVPA/H85-5 QVECTOR CNVGC HAVE SOME TIME TO SATURATE DRY ANTECEDENT AIR. GFS/ETA FCST H100-85 THKNS/MOS SUG PCPN WL BE RA...BUT WL MAINTAIN A MIX WITH SN OVER FAR NRN LWR AND THE ERN U.P. TO ACCOUNT FOR EVAP COOLING. IN GENERAL...TEMPS WL REACH THEIR LOWEST LVLS FAIRLY EARLY IN THE NGT...WITH READINGS RISING LATER UNDER WAD/THICKENING CLDS. ETA/GFS SHOW DISAGREEMENT ON THU WITH REGARD TO HOW QUICKLY MSTR RIBBON PUSHES TO THE E. ETA IS MORE ZONAL WITH FCST FLOW ALF...SO DRY SURGE FCST TO PUSH EWD MUCH FASTER THAN DEPICTED BY THE GFS... WHICH INDICATES A MORE AMPLIFIED FLOW AND FA REMAINING IN LEFT EXIT OF SUPPORTING JET MAX LONGER. GIVEN TREND TOWARD A HIER AMPLITUDE TROF IN THE E AND STRENGTH OF SHRTWV...WL GO WITH THE SLOWER GFS SOLN AND MAINTAIN POPS THRU THE DAY THU. LIKELY POPS SEEM JUSTIFIED IN THE MRNG PER GFS MOS ONCE THE STRENGTH OF THE DYNAMICS OVERCOME DRY AIR. UNDERCUT GFS MOS FOR TMAX GIVEN WDSPRD CLD COVER...CLOSER TO LWR NGM MOS. AS MAIN UPR JET/SHRTWV SLIDES SEWD THU NGT...GFS SHOWS MSTR RIBBON/H85-5 QVECTOR CNVGC/H7 UVV GRDLY DSPTG. LLVL DRY ADVCTN FM THE NE WL ALSO AID COLLAPSE OF ACCOMPANYING PCPN. AS H100-85 THKNS DROPS WITH COLD/DRY ADVCTN...LINGERING PCPN WL TEND TO CHG TO MAINLY SN. BUT ARRIVAL OF DRIER AIR WL ALSO DCRS PCPN CHCS. EXTENDED MODELS POINT TOWARD MEAN TROF OVER ERN NAMERICA WITH CONTINUED BLO NORMAL TEMPS INTO NEXT WEEK AS ARCTIC HI PRES BLDS ACRS SCNTRL CAN...MAINTAINING A COOL NNE FLOW INTO THE UPR GRT LKS. INSTABILITY -SHSN MAY LINGER ON SAT INTO SUN WITH H85-7 THERMAL TROF UPSTREAM. HOWEVER...DRY AIRMASS ALF AND TREND TOWARD INCRSG ACYC FLOW SHUD MITIGATE PCPN COVG/INTENSITY WITH H85-5 QVECTOR DVGC AND STRG SUBSIDENCE FCST. CONSIDERED DROPPING POPS ALTOGETHER FOR THESE PDS. PCPN MAY GET A BOOST ON SUN AS SHRTWV PASSES. 00Z OPERATIONAL GFS HINTS AT DEVELOPMENT OF DEEPER LO PRES IN THE OH VALLEY EARLY NEXT WEEK UNDER INCRSG NEGATIVE TILT UPR TROF...BUT WL TEND TOWARD THE WEAKER ECWMF SOLN THAT SHOWS THE SFC LO MUCH FARTHER SE PER NCEP DISCUSSION AND 00Z GFS ENSEMBLE MEAN. 06Z GFS ALSO SUPPORT THE WEAKER...FARTHER SE TRACK. SO...LWR POPS THAN INDICATED BY 00Z GFS MOS FOR NEXT MON WITH A DRY DAY ON TAP. BUT A MORE CYC FLOW BY NEXT TUE UNDER FALLING UPR HGTS WITH THE ARRIVAL OF ANOTHER UPR SHRTWV JUSTIFIES CHC POPS THEN. TEMPS APPEAR LO ENUF FOR INSTABILITY SHSN. COORDINATED WITH MQT/GRR. KC && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 325 PM EDT TUE APR 6 2004 .DISCUSSION... A COUPLE OF ISSUES HERE TO RESOLVE...JUST ABOUT ALL OF THEM MINOR. DESPITE SOME IMPRESSIVE RETURNS ON KGRR RADAR...CEILINGS AT 7K FEET TELL THE STORY WITH ONLY SPRINKLES HITTING THE GROUND TO OUR WEST. THIS ACTIVITY OCCURRING IN AREA OF ENHANCED THETA-E ADVECTION. BEST ADVECTION WILL BE CONFINED TO THE SOUTH HALF OF THE CWA THROUGH ABOUT 00Z THEN SLIDE EAST TAKING PRECIP OUT OF THE AREA. WILL CARRY SCT -SHRA THROUGH THE EARLY EVENING...MAINLY SOUTH...OTHERWISE DRY. OTHER ISSUE WILL BE WITH CLOUDS. MESOETA IS FAIRLY AGGRESSIVE IN BRINGING LOW CLOUDS DOWN ACROSS MUCH OF THE CWA AS LOW PASSES TO OUR EAST AND COLD FRONT DROPS IN BEHIND THE LOW. CURRENTLY MESOETA IS OVERDONE ON RH FIELD...PARTICULARLY ACROSS NW LOWER MICHIGAN. NGM AND RUC SUGGEST BULK OF LOW LEVEL MOISTURE WILL PASS TO OUR EAST. WILL CARRY MOSTLY CLOUDY FOR THUMB TONIGHT AND PARTLY CLOUDY ELSEWHERE. EXPECT WHATEVER CLOUDS ARE AROUND WEDNESDAY MORNING TO GIVE WAY TO PARTLY/MOSTLY SUNNY SKIES FOR AFTERNOON. MAX TEMPS A LITTLE TRICKY. TEMPERATURES IN WI WARMING NICELY THIS AFTERNOON WITH READINGS INTO THE 60S...AND LIKELY TO HIT 70 BEFORE THE DAY IS DONE. HOWEVER...A COUPLE OF FACTORS TO CONSPIRE TO HOLD TEMPS DOWN HERE TOMORROW...850MB TEMPS SOME 3-5C LOWER THAN WI...HIGH OVERHEAD LIKELY TO LIMIT MIXING...AND FINALLY LIGHT 950MB WINDS SHOULD PROMOTE DEVELOPMENT OF AT LEAST A WEAK LAKE BREEZE. NEXT ISSUE WILL BE PRECIP CHANCES ON THURSDAY. MODELS HAVE SLOWED SYSTEM SOME...ENOUGH TO REMOVE LIGHT PRECIP CHANCES FOR NW CWA WEDNESDAY NIGHT. ETA LOOKS TO BE THE MORE CONSISTENT OF THE MODELS IN TERMS OF STORM TRACK AND LIFT. WITH THIS THOUGHT IN MIND...WILL LEAN TOWARD ETA SOLUTION. LIMITING FACTOR AS FAR AS PRECIP IS CONCERNED PER ETA...IS LIMITED MOISTURE WITH LOW PUSHING THROUGH CWA. PLAN TO CONTINUE WITH CHANCE POPS. WILL CARRY CHANCE OF SHRA-BOTH ETA AND GFS THICKNESSES WOULD SUPPORT RAIN. AS LOW PULLS OUT...ETA WANTS TO SWING UPPER LEVEL CUTOFF ACROSS THE REGION...WHILE GFS STREAMS A RIBBON OF CHANNELED VORTICITY ACROSS CWA. WILL LINGER THURSDAY PRECIP INTO THURSDAY EVENING...THEN HOLD DRY. EXTENDED... WILL THERE BE SNOWFLAKES ON YOUR EASTER BONNET. THAT AMONG OTHER ITEMS CONFRONTS US HERE. MODELS IN GOOD AGREEMENT IN EVOLVING LONG WAVE TROUGH TO THE WEST OF US DURING THE PERIOD...WITH GFS CUTTING OFF SYSTEM INTO UPPER LOW ACROSS THE UPPER MIDWEST LATE IN THE PERIOD. DOMINATING FEATURE THROUGH THE EXTENDED WILL BE STRONG ARCTIC HIGH PRESSURE THAT WILL CROSS CANADA...PROVIDING CWA WITH DRY NORTHEAST FLOW. COLD AIR WILL FILTER INTO THE CWA AS THE HIGH SWINGS THROUGH CANADA...WITH 850MB TEMPS DROPPING TO -8C SUNDAY /EASTER/ MORNING. CLIMO IS AROUND 1C. GFS HAS HAD DIFFICULTY RESOLVING PRECIP CHANCES ACROSS CWA...WITH CURRENT GFS/CANADIAN PRECIP ENSEMBLES OFFERING LITTLE SUPPORT FOR PRECIP ON SUNDAY. WILL KEEP SUNDAY DRY...BUT NOTE...THAT IF GFS WERE TO VERIFY...SOME SNOWFLAKES COULD FLY ON EASTER. MOVING INTO MONDAY-TUESDAY PERIOD...STILL DIFFERENCES IN MODELS...AND AMONG MODELS. GFS PUSHES POTENT SURFACE LOW RIGHT THROUGH CWA /YESTERDAY/S GFS HAD LOW NEAR BOSTON...LATEST 12Z GFS NOW PROMOTING EAST COAST LOW-STAY TUNED./...WHILE ETA-XX BY EXTRAPOLATION ARGUES FOR A SOLUTION MORE IN LINE WITH YESTERDAY/S GFS. GFS PRECIP ENSEMBLES DO POINT TO AT LEAST CHANCE POPS FOR MONDAY INTO TUESDAY. WITH THIS IN MIND WILL CALL FOR CHANCE RAIN/SNOW MONDAY...THEN ALL RAIN MONDAY NIGHT AND TUESDAY. WITH CONSIDERABLE UNCERTAINTY STILL IN THE PICTURE...WILL HOLD TO ONLY CHANCE POPS. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ OKEEFE EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1155 AM EDT TUE APR 6 2004 .UPDATE... UPDATE SENT OUT...MAINLY TO REMOVE MORNING WORDING. FORECAST LOOKS TO BE IN GOOD SHAPE. TWEAKED TEMPS DOWN ACROSS THE MIDDLE PART OF THE CWA...AS CLOUDS AND SCATTERED LIGHT SHOWERS PERSIST THOUGH MOST OF THE AFTERNOON. CLEARING NOW BEGINNING TO WORK INTO WESTERN NORTHERN LOWER MICHIGAN...AS TEMPERATURES HAVE CLIMBED WELL INTO THE 50S WITH SUNSHINE ACROSS WISCONSIN. GOOD DRYING INDICATED ON THE WATER VAPOR IMAGERY WORKING INTO THE U.P. TEMPERATURES HAVE ALSO CLIMBED INTO THE MID TO UPPER 50S ACROSS EXTREME SOUTHWEST LOWER MICHIGAN WITH SOME SUNSHINE. TEMPERATURES SHOULD BE ABLE TO REACH THE UPPER 50S ACROSS THE SOUTHERN THIRD OF THE CWA BEFORE THE WEAKENING LINE OF LIGHT SHOWERS SAGS SOUTH. ACROSS THE TRI-CITIES REGION...BANKING ON SOME SUNSHINE LATE IN THE DAY...WHICH WILL ALLOW TEMPS TO RISE INTO THE MID 50S. THE TOUGHEST CALL FOR TEMPS REMAINS ALONG THE M-59 CORRIDOR AND THUMB REGION WHERE CLOUDS ARE EXPECTED TO PERSIST THE LONGEST. EVEN WITH CLOUDS...EXPECT TEMPS TO MAKE AT LEAST 50 DEGREES LATE TODAY AS THE LOW LEVEL WARM ADVECTION CONTINUES. SCATTERED LIGHT SHOWERS WILL LIKELY BE OVER IN THE TRI-CITIES REGION BY 4 PM...WITH THE DRYING TREND SINKING SOUTH THROUGH THE REST OF THE AFTERNOON. SF .DISCUSSION ISSUED AT 315 AM... SHORT WAVE TROF WAS APPROACHING THE WESTERN GREAT LAKES AND APPEARANCE ON THE H2O VAPOR LOOP THIS MORNING IS LESS THAN IMPRESSIVE. NOT MUCH UPPER LEVEL SUPPORT WITH SATELLITE DERIVED WINDS ON THE ORDER OF 50KTS OR LESS. RADAR MOSAICS SHOW AN INCREASING AREA OF PRECIPITATION FROM THE DOOR PENINSULA INTO THE U.P. THANKS TO AN AXIS OF LLJ/THETA-E ADVECTION AND ISENTROPIC LIFT 295-300K SURFACES PER THE LATEST ANALYSIS FROM THE RUC. THIS WILL BE OUR FIRST FORECAST CHALLENGE TO BE FOLLOWED BY ADDITIONAL SHORT WAVES IN OUR NORTHWEST FLOW REGIME TOWARD THE LATTER HALF OF THIS WEEK. PWAT/S ACROSS THE STATE ARE QUITE LOW PER 00Z RAOBS, ON THE ORDER OF A QUARTER OF AN INCH. AS UPSTREAM PRECIP APPROACHES THE DRY AIR MASS, CEILINGS ARE DROPPING BUT NOT MUCH LESS THAN 4500 FEET WITH VISIBILITIES GENERALLY AT THE 10SM. SOUTH OF THE MAIN AREA OF PRECIP IT APPEARS PLENTY OF VIRGA AS GRB 00Z SOUNDING IS QUITE DRY... EVEN DRIER ACROSS ILLINOIS. MODELS ARE CONSISTENT WITH THE APPROACH OF THIS TROF AND ASSOCIATED COLD FRONT BUT PRECIP CHANCES APPEAR TO BE ON THE DECREASE. CASE AND POINT, THETA-E ADVECTION FIELDS BECOME DIS-ORIENTED LATER THIS MORNING AS DOES OMEGA PATTERN WEAKENING. HOURLY BUFKIT PROFILES VIA THE ETA SHOW DRY AIR HANGING ON BELOW 5K FEET THROUGH THE DAY DESPITE ISENTROPIC ANALYSIS INDICATING GOOD UPGLIDE AND CPD/S LESS THAN 10MBS. FOR CONSISTENCY, AND AFTER COLLABORATION, WE WILL CONTINUE WITH THE SCATTERED SHOWERS NORTH OF I69 WHERE EXPECTED MOISTURE PROFILES REMAINS DEEP ENOUGH AND DROP OFF THE POPS FURTHER SOUTH TOWARD THE BORDER WHERE ISOLATED SHOWERS WILL BE IN THE GRIDS. TEMPERATURES WILL BE ANOTHER ISSUE AS UPSTREAM HIGHS IN ADVANCE OF THIS FRONT WERE INTO THE 70S (THEY DID HAVE MORE SUNSHINE AND THERMAL FIELDS WERE WARMER). WHILE WE WILL NOT REACH THOSE VALUES, THINKING WAS TO RAISE OUR GRIDS CLOSER THE MET GUIDANCE NUMBERS WHICH SUPPORTS AROUND 60F. SUBSIDENCE AND DRY AIR WORK INTO THE STATE TONIGHT AS FRONT CLEARS THE SOUTHERN MICHIGAN BORDER EARLY THIS EVENING. SOUNDINGS SUPPORT PLENTY OF DRY AIR ALOFT BUT, ONCE AGAIN, THEY HINT AT LOW LEVEL STRATUS DEVELOPING/ADVECTING ACROSS MOST OF THE CWA. ETA40 BOUNDARY LAYER AND 30AGL CPD/S DROP BELOW 10MBS TOWARD 06Z WITH NORTHWEST FLOW AT THE SURFACE AROUND 10 KNOTS. SO IT SEEMS FOG SHOULD NOT BE THE ISSUE, BUT LOW CLOUDS WHERE WE MIGHT ON THE BORDERLINE OF MVFR/IFR CEILINGS. WE WILL ACCOUNT FOR THIS WITH A MOCLOUDY SKY EVOLVING ACROSS THE NORTHERN 2/3RDS OF THE CWA OVERNIGHT. ILL-DEFINED HIGH PRESSURE SLIDES SOUTHEAST ACROSS THE STATE ON WEDNESDAY WHERE ANY LOW CLOUDS BURNING OFF LEAVING BY SOME SUNSHINE. MIXING LAYER HEIGHTS SUPPORT HIGHS CLIMBING INTO THE 50S AND WITH SOME SUNSHINE, THIS SHOULD BE ATTAINABLE WHICH WOULD AGREE CLOSER THE MAV/S AND SOME BLEND OF THE MET/S. HOW TO HANDLE THE NEXT SYSTEM IN OUR NORTHWEST FLOW IS ANYONE/S GUESS WITH MODELS CONSENSUS SHOWING CLOUDS INCREASING WEDNESDAY NIGHT. THE GFS POINTS TOWARD TWO DISTINCT AREAS OF LIFT THURSDAY WHICH BISECTS THE CWA. THE ETA IS MORE CONCENTRATED TOWARD THE NORTHERN WAVE WHICH MAKES MORE SENSE GIVEN LOCATION OF UPPER JET. THEN THERE IS THE ETA-XX, WHICH HAS DONE WELL OF LATE, WEAKENS THE NORTHERN WAVE IN FAVOR OF SURFACE CYCLOGENESIS ACROSS THE OHIO VALLEY. GIVEN A VARIETY OF SOLUTIONS AND EXPECTED TEMPERATURE PROFILES, WE WILL LEAVE CURRENTS GRIDS INTACT WITH RAIN/SNOW LINE NORTH OF M59. LOOKING AHEAD...PLENTY TO WATCH FOR AS WE AWAIT TO SEE HOW PATTERN EVOLVES WITH UPPER LOW CLOSING OFF SOMEWHERE OVER THE PLAINS AND GULF OF MEXICO BECOMING ENTRAINED. LATEST ECMWF/GFS/ETA-XX/GEM KEEP THE SURFACE LOW SOUTH OF THE OHIO VALLEY AND FAVOR THE EAST COAST. APRIL DOES HAVE ITS SURPRISES AND WE WILL WATCH CLOSELY OVER THE NEXT SEVERAL DAYS. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BGM EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 904 PM EDT TUE APR 6 2004 .UPDATE... ONLY CHANGES THAT WILL BE NEEDED FOR THE UPDATE WILL BE TO REFRESH THE WORDING TO REMOVE THE MENTION OF EVENING. UPSTREAM SOUNDING AT ILN SHOWS MID LEVEL MOISTURE...WHICH BOTH THE RUC AND THE MESOETA BRING INTO OUR AREA AFTER MIDNIGHT. SO WILL STICK WITH PARTLY CLOUDY SKIES OVERNIGHT. TEMPERATURES ARE GENERALLY RUNNING CLOSE TO FORECAST VALUES AND THE LATEST GUIDANCE IS ON TRACK...SO WILL LEAVE LOWS IN THE LOWER 40S. && .PREV DISCUSSION... TONIGHT-WED: HIGH PRESSURE SLIDES OFF TO OUR SOUTH TONIGHT & ENSUING WSW LOW LEVEL FLOW WILL INTRODUCE HIGHER DEWPOINTS STARTING THIS EVENING. WEAK WARM FRONTAL FEATURE WILL TRACK EAST ACROSS NC EARLY WED MORNING & INTRODUCE SOME VERY MILD AIR WITH TRAJECTORIES SUPPORTING AN INCREASE IN MID CLOUDS LATE TONIGHT INTO WED. FAVOR LOWS TONIGHT CLOSER TO THE COOLER GFS MOS GUIDANCE GIVEN THE LIGHT SURFACE WINDS & JUST PATCHY CLOUDS FOR THE BULK OF THE NIGHT. EXPECT HIGHS TOMORROW TO GET WELL INTO THE MID TO UPPER 70S BASED ON THICKNESSES & 850 MB TEMPS ALONG WITH THIS AFTERNOON'S TEMPS UPSTREAM. WED NIGHT THROUGH THU NIGHT: CLOSED UPPER LOW OVER THE SOUTHWEST PLAINS OPENS UP AND FILLS LATE WED INTO WED NIGHT AS IT HEADS EAST WITH ISENTROPIC UPGLIDE DEVELOPING OVER NC. HOWEVER THE UPGLIDE IS WEAK AS IS ANY OTHER FORCING FOR LIFT. WITH MOST OF THE PVA TO OUR SOUTH AND UPPER JET DEVELOPMENT OVER THE GULF PRESENTING A CHANCE OF GULF CONVECTION WHICH MAY LIMIT QPF OVER CENTRAL NC... PRECIP PROBABILITIES IN THE LOW CHANCE CATEGORY THU THROUGH THU EVENING STILL LOOK GOOD. MODELS DEPICT ENOUGH WARMING IN THE MID LAYERS TO LIMIT INSTABILITY... SO WILL CONTINUE TO OMIT THUNDER FOR NOW. WILL RAISE TEMPS WED NIGHT A FEW DEGREES FROM CURRENT NUMBERS BUT FEW SIGNIFICANT CHANGES OTHERWISE. FRI: DEEP NW FLOW IN THE WAKE OF THE DEPARTING WAVE WILL BRING DRIER AIR... HOWEVER THE COOL PUNCH IS WEAK AND SHORT-LIVED AS ANOTHER DAMPENING WAVE COMING OUT OF THE SOUTHWEST BUILDS WEAK RIDGING OVER THE SOUTHEAST. HIGH TEMPS SHOULD BE NEAR NORMAL... NEAR 70 TO THE LOWER 70S. -GIH SAT THROUGH TUE: SURFACE LOW TRACKS EAST ALONG OLD FRONTAL BOUNDARY TO THE SOUTH AND LIFTS BACK NORTH AS A WARM FRONT ON SATURDAY. LACK OF UPPER LEVEL SUPPORT AND BRIEF DURATION OF SW FLOW UPGLIDE LATE SATURDAY AFTERNOON AND SATURDAY NIGHT...SO QPF SHOULD BE LIGHT. LULL ON SUNDAY AS SHORTWAVE TROUGH DEEPENS AND DIGS OVER THE NATIONS MID-SECTION. AMPLIFIED FLOW FINALLY PROVIDES DEEP MOISTURE OVER THE SOUTHEAST... AS INVERTED TROUGH LIFTS NORTH OUT OF THE GULF AND INTO THE MID-ATLANTIC REGION BRINGING A CHANCE OF SHOWERS AND THUNDER MONDAY AND TUESDAY. -BL && .RAH WATCHES/WARNINGS/ADVISORIES... NC...NONE. && $$ DGS nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 950 AM EDT TUE APR 6 2004 .PUBLIC...EXCEPT FOR SLIGHT MOISTURE AT UPPER LEVELS ALLOWING FOR THIS CIRRUS HERE AND THERE ACRS THE AREA...TIME HEIGHTS INDICATE RATHER DRY CONDS UNDER THE LARGE HIGH PRES DOME SLIDING OVER THE SE CONUS. MOSUNNY SKIES WILL PREVAIL. THIS WILL ALLOW TEMPS TO RISE NICELY TO FCSTD VALUES...PARTICULARLY AS WINDS VEER TO SELY BY MID AFTN AS ADVERTISED ON THE RUC AND WSETA. 06Z MAV TEMPS STILL A TOUCH COOL. WILL MAKE ONLY COSMETIC WORDING CHANGES TO CURRENT ZONES AS ALL FORECAST ELEMENTS LOOK ON TRACK. && .FIRE WEATHER...TRENDS AND TIMING OF LOWEST RH VALUES LOOK ON TRACK. WILL CONTINUE IDEA OF NO RFW OR FWW AS WINDS WILL BE BELOW CRITERIA BUT WILL LEAVE HEADLINE/COMMENTS AS IS. NO UPDATE NEEDED. && .MARINE...PRESENTLY A NORTHEAST FLOW AROUND 15 KNOTS ACROSS THE SOUTH CAROLINA WATERS AND CHARLESTON HARBOR...AROUND 5 KNOTS OVER THE GEORGIA WATERS. WILL UPDATE THE SOUTH CAROLINA WATERS AND CHARLESTON HARBOR TO BUMP UP WINDS TO NORTHEAST 15 KNOTS. STILL EXPECTING A QUICK SHIFT TO SOUTHEAST IN THE AFTERNOON. FOR THE GEORGIA WATERS WILL CHANGE MORNING FORECAST OF VARIABLE 5 KNOTS TO NORTHEAST 10 KNOTS. EXPECTING A QUICK SHIFT TO SOUTHEAST THERE IN THE AFTERNOON AS WELL. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$ JPC/AUSTIN sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 910 PM CDT TUE APR 6 2004 .UPDATE... LATEST SATELLITE AND WSR-88D DATA INDICATE SHOWERS AND A FEW THUNDERSTORMS CONTINUING ACROSS THE BIG COUNTY. SPECIFICALLY... SATELLITE DATA INDICATES WRAP-AROUND MOISTURE FROM UPPER-LEVEL LOW...CURRENTLY MOVING ACROSS THE TEXAS PANHANDLE...WILL MAINTAIN MOSTLY CLOUDY SKIES ACROSS THE BIG COUNTRY FOR THE REMAINDER OF TONIGHT AND MOST OF TOMORROW. BASED ON THIS DATA AND ON LATEST RUC MODEL DATA...SENT AN UPDATE TO REMOVE FIRST PERIOD POPS FROM THE HEARTLAND AND ADJUST FIRST AND SECOND PERIOD CLOUDS AND WINDS. OTHERWISE...NO OTHER CHANGES. && .PREV DISCUSSION... UPPER LEVEL LOW WAS OVER THE TEXAS PANHANDLE THIS AFTERNOON... SHOWING LITTLE MOVEMENT. VISIBLE IMAGERY SHOWED THE CUMULUS IN THE BIG COUNTRY MORE DEVELOPED AND ENHANCED THAN FURTHER SOUTH...BEING MORE UNSTABLE NEAR THE UPPER LOW...WITH AN ISOLATED SHOWER DEVELOPING NORTH OF SWEETWATER. STILL HAVE A POTENTIAL FOR SOME THUNDERSTORMS...WITH SPC SHOWING A SLIGHT RISK NORTH OF ANSON TO BROWNWOOD LINE. MAY SEE SOME STORMS THIS AFTERNOON AND EVENING AS A DISTURBANCE ON WEST SIDE OF UPPER LOW ROTATES INTO THE BIG COUNTRY. UPPER LOW OVER IN PANHANDLE TO MOVE EAST INTO OKLAHOMA WEDNESDAY... WITH NORTHWEST SURFACE WINDS BRINGING IS DRIER AND MORE STABLE AIR TO WEST CENTRAL TEXAS. MAY SEE SOME WRAPAROUND CLOUDS CONTINUING IN THE BIG COUNTRY DURING THE MORNING HOURS. MOISTURE AND INSTABILITY NOT FAR SOUTH HOWEVER...RETURNING ON THURSDAY WITH AFTERNOON CAPES OF 1000-2000 J/KG RANGE. KEPT SLIGHT CHANCE OF THUNDERSTORMS ON THURSDAY...AND ON FRIDAY WITH A DRYLINE SETUP. STRONG COLD FRONT MOVES INTO THE THROUGH CWA ON SATURDAY. LARGE SCALE UPPER TROUGH APPROACHES THE REGION OVER THE WEEKEND...AND MOVES OVER MONDAY. KEPT SLIGHT CHANCE/CHANCE POPS GOING INTO SUNDAY NIGHT. LATER SHIFTS MAY NEED TO EXTEND THEM INTO MONDAY AS 12Z GFS APPEARS TO BE SLIGHTLY SLOWER. && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/HUBER tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 338 AM MDT WED APR 7 2004 .SHORT TERM (TODAY-THURSDAY NIGHT)...KGJX RADAR INDICATING SHOWERS STUBBORNLY HOLDING ON ESPECIALLY ACROSS THE NORTH EARLY THIS MORNING. BELIEVE IT/S DUE TO WEAK DEFORMATION ZONE ACROSS THE AREA...BETWEEN CLOSED LOW IN SRN NV AND CLOSED LOW OVER THE SRN PLAINS. RUC SHOWS DIV/CONV COUPLET WEAKENING AFT 12Z...SO EXPECT SCT PCPN SHOULD TAPER OFF TO ISOLD THIS MORNING...BEFORE PICKING UP AGAIN THIS AFTN WITH DAYTIME HEATING. AT FIRST LOOK...SCENARIO SHAPING UP TO BE SIMILAR TO STORM THAT AFFECTED THE AREA THIS PAST WEEKEND...THOUGH LENGTHY DURATION NOT INDICATED THIS TIME AROUND. ETA/GFS TAKE CLOSED LOW OVER SRN NV TO CNTL AZ TODAY...THEN E INTO NM ON THU. DEEP POTENTIAL INSTABILITY TODAY...AND EXPECT SCT SHOWERS/TSTMS THIS AFTN AS THE INSTABILITY REALIZED WITH HEATING. BEST DYNAMIC LIFT SHOULD BE SE UT/SW CO AS LOW DROPS INTO AZ WHERE HIGHEST POPS LOCATED. ENOUGH MOISTURE PRESENT WITH SFC DEWPTS 35-45 F AND PWATER FROM 00Z SOUNDING AROUND .50 INCH. STORMS SLOW MOVING AS WEAK FLOW REGIME CONTINUES...WITH LOCALLY MOD- HVY RAIN POSSIBLE 4-CORNERS AREA. MOIST S-SE FLOW WED NIGHT-THU MORNING WITH BEST CHANCE OF PCPN FOCUSED ON SAN JUANS LOWER ELEV OF 4-CORNERS...THOUGH 700 MB WINDS FORECAST 10 MPH OR LESS. 700 MB FLOW THEN SHIFTS TO THE SW THU AFTN. VORT LOBE ROTATES INTO SW CO FOR ADDED LIFT THU MORNING WITH INSTABILITY CONTINUING THU AFTN. HAVE UPPED POPS GRIDS TO HIGH CHANCE FOR THIS AREA TONIGHT AND THU. MODELS CURRENTLY HAVE LOW MOVING E THU NIGHT...WITH SHORTWAVE IN NW FLOW THEN BRINGING CHANCE OF PCPN AND COOLER TEMPS TO MAINLY THE NORTH THU NIGHT. .LONG TERM (FRIDAY-WEDNESDAY)...MODELS REMAIN IN FAIRLY GOOD AGREEMENT WITH NEXT SIGNIFICANT SHORTWAVE TROF DROPPING SOUTH OVER THE MOUNTAIN WEST THURSDAY NIGHT INTO FRIDAY. DETAILS A BIT SKETCHY AS EC A BIT SLOWER...UKMET FARTHER WEST AND TRENDING TOWARD CLOSING OFF SYSTEM. GFS IN BETWEEN THESE SOLUTIONS WITH VIGOROUS WAVE MOVING SOUTHWARD ACROSS THE CWFA FROM MIDDAY FRIDAY THROUGH FRIDAY NIGHT. RUN TO RUN CONSISTENCY HAS BEEN GOOD WITH THE GFS AND DIFFERENCES WITH OTHER MEDIUM RANGE MODELS NOT EXTREME. FOR THESE REASONS GFS THE PREFERRED MODEL AND WILL BASE EXTENDED FORECAST ON THIS SOLUTION. FRIDAY-MONDAY: AS ALLUDED TO ABOVE...UNSETTLED AND COOLER PRETTY WELL SUMS UP THE FORECAST FOR THE COMING WEEKEND INTO EARLY NEXT WEEK. GFS DROPS COLD FRONT ACROSS THE CWFA FROM FRIDAY AFTERNOON INTO SATURDAY NIGHT. CONVERGENCE ALONG THE FRONT COMBINED WITH ALREADY MOIST LOWER ATMOSPHERE...STEEP LAPSE RATES AND FAVORABLE OROGRAPHICS HINTS AT SOME SIGNIFICANT SNOWFALL ACROSS THE NORTHERN AND PORTIONS OF THE CENTRAL MOUNTAINS WITH THE FIRST PUSH OF COOLER AIR. REINFORCING SHOT OF COOLER AIR INDICATED FOR SUNDAY INTO SUNDAY NIGHT SO CHANCES REMAIN GOOD FOR SCATTERED SHOWERS IN THE HIGH COUNTRY...WITH MORE ISOLATED ACTIVITY OVER THE VALLEYS. TUESDAY-WEDNESDAY: PACIFIC TROF WILL BUILD RIDGE OVER THE REGION BY MIDWEEK. THEREFORE...CARRIED WARMING TREND WITH DECREASING CLOUDS. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. $$ JAD/NL co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 500 AM CDT WED APR 7 2004 .DISCUSSION... IN THE NEAR TERM, OBJECTIVE ANALYSIS REVEALS THE RECENT COLD FRONT HAS BECOME QUASI-STATIONARY AND ALIGNED WEST-TO-EAST BISECTING PORTIONS OF THE SRN CWA. THE FRONT IS PROGGED BY THE FSL RUC-20 AND ETA TO MIX NORTHWARD TODAY ACROSS THE WRN TWO THIRDS OF THE CWA ALLOWING FOR RELATIVELY WARM TEMPS TO BE REALIZED, BUT NOT AS WARM AS YESTERDAY. THE PROGGED MOTION APPEARS REASONABLE BASED ON CURRENT ISALLOBARIC TRENDS. A STRONGER COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT ASSOCIATED WITH A MID-LVL S/WV TROUGH THAT WILL PASS NORTH OF NRN IL. THE JUXTAPOSITION OF THE LOW- AND MID-LVL KINEMATIC AND THERMO FIELDS SUPPORT THE INHERITED HIGHER SHRA POPS ACROSS THE NRN PORTION OF THE CWA. THE SHRA SHOULD BE EAST OF THE CWA AROUND SUNRISE THR. HAVE FOLLOWED THE ETA AND EC FOR THE FIRST HALF OF THE EXTENDED AS THE GFS/UKMET/GEM CONTINUE TO BE TOO PROGRESSIVE WITH THE PHASING OF THE UPR-LVL LOW CURRENTLY PARKED OVER THE TX PHNDL/WRN OK, WITH THE SRN BRANCH OF THE POLAR JET. HOWEVER, FOR THE LATER PERIODS THE OPERATIONAL GFS AND ITS ENSEMBLE ARMADA ARE PREFERRED. USING THE H85 THETA-E AS AN AIRMASS PROXY...FOLLOWING TONIGHT'S FROPA CAA SHOULD PERSIST THROUGH THE WEEKEND REINFORCED BY A SERIES OF WEAK S/WV TROUGHS ROTATING AROUND THE BASE OF A THEN AMPLIFYING L/WV TROUGH COMPOUNDED BY AN UPR-LVL LOW THAT WILL LIFT OUT OF THE CNTRL ROCKIES/CNTRL PLAINS AND ACROSS THE OH VALLEY EARLY IN THE WEEKEND. THE INHERITED POPS AND PRECIP TYPES APPEAR REASONABLE BASED ON THE RECENT 00Z GUIDANCE...SOME QUESTION AS TO HOW MUCH PRECIP WILL BE REALIZED GIVEN THE AMOUNT OF DRY AIR THAT WILL BE IN PLACE...THE SRN PORTION OF THE CWA WOULD BE FAVORED FOR PRECIP BASED ON THE PROGGED TRACK OF THE CNTRL PLAINS LOW. HAVE LOWERED MIN/MAX TEMPS FOR THE WEEKEND INTO MONDAY BASED ON THE ANTICIPATED AIRMASS. THE LATEST MEX HAS MOVED TOWARD A COLDER SOLUTION AS WELL. RELATIVELY COLD AND UNSETTLED CONDITIONS SHOULD PERSIST INTO THE BEGINNING OF NEXT WEEK AS THE L/WV TROUGH IS MAINTAINED OVER THE REGION. TEMPS SHOULD MODIFY TOWARD THE MIDDLE OF THE WEEK. THANKS MKE AND DVN CONCERNING ISC COORDINATION. 05 && .AVIATION DISCUSSION FOR 12Z TAFS... GENERALLY CLEAR WITH LIGHT EAST WINDS THRU THE MORNING...SHIFTING TO SOUTHEAST BY NOONISH. ADVANCING CLIPPER FROM THE UPR MS VLY TONGT SHUD RESULT IN AN INCREASE IN MID DECK BY 9PM OR 10PM WITH A SMALL THREAT OF RAIN. AM LEAVING OUT ANY MENTION OF RAIN IN TERMINALS THIS EVENING BECAUSE OF GRREATER UNLIKELIHOOD. FROPA BEFORE SUNUP AROUND 10Z SHUD RESULT IN WNDS SHIFTING TO NW TO 12 KTS...ACCOMPANIED BY CLEARING SKIES. RLB && .LOT...WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LK MI...NONE. $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1245 AM EST WED APR 7 2004 .AVIATION... LITTLE CHANGE TO GOING TERMINAL FORECASTS. CONTINUED VFR THROUGHOUT FORECAST PERIOD. A WEAK SYSTEM WITH LIMITED MOISTURE APPROACHES TOWARD END OF FORECAST PERIOD AND HAVE INDICATED VCSH TOWARD BEYOND 04Z AT KSBN. && .UPDATE... QUICK UPDATE THIS EVENING TO FRESHEN ZFP WORDING BY REMOVING EARLY EVENING POPS. DECIDED TO LEAVE SOME SPRINKLES IN SOUTHERN COUNTIES UNTIL FRONT COMPLETELY CLEARS THAT AREA. STILL SOME CLOUDS SEEN ON SATELLITE WITH THIS FRONT AND RUC40 GENERATING SOME DECENT 850MB OMEGA BEFORE 06Z. HOWEVER...LOWER LEVELS QUITE DRY AND WITHOUT SIGNIFICANT FORCING JUST DO NOT SEE MUCH IN THE WAY OF MEASURABLE PCPN OCCURING. DECIDED TO RAISE MAX TEMPS FOR WED BASED ON OBJECTIVE GUIDANCE TRENDS LAST SEVERAL RUNS AND UPSTREAM TEMPERATURES BEHIND COLD FRONT TODAY. EXPERIMENTAL WAM NUMBERS ALSO SUPPORTING WARMER TEMPERATURES. BIGGEST CHANGE WAS TO CONFINE LAKE EFFECTS ON TEMPERATURE CLOSER TO LAKE MICHIGAN. LOW LEVEL WINDS SHOULD BE MORE NORTHEAST AND LIGHT BUT STILL EXPECT A LAKE BREEZE TO DEVELOP...JUST NOT MOVE INLAND AS MUCH AS PREVIOUS GRIDS INDICATED. THUS SBN TEMPERATURE WILL BE WARMER. && .PREV DISCUSSION... SHORT TERM... A WEAK COLD FRONT WILL BE MOVING THROUGH THE AREA LATE THIS AFTERNOON/EVENING. A FEW RAIN SHOWERS ARE ASSOCIATED WITH THE FRONT WHICH ARE CURRENTLY MOVING SOUTHEASTWARD THROUGH OUR MICHIGAN COUNTIES. NOT EXPECTING MUCH RAIN FROM THIS FRONT. NOT VERY MANY CLOUDS CURRENTLY IN NORTHERN ILLINOIS...MOST OF THE CLOUDS ARE OVER LAKE MICHIGAN AND SOUTHERN MICHIGAN. JUST KEPT THE LOW CHANCE POPS WITH THE FRONTAL PASSAGE. AFTER FRONTAL PASSAGE...THE RAIN CHANCES WILL END AS DRIER AIR IS BEHIND THE FRONT. ALSO WINDS TONIGHT WILL TURN TO THE NORTH AND THEN TO THE NORTHEAST TOMORROW MORNING. 12Z TOMORROW MORNING THE MODELS HAVE THE FRONT OVER SOUTHERN INDIANA AND THEN DURING THE DAY MOVE IT SOUTH OF THE STATE AS HIGH PRESSURE MOVES IN. TEMPERATURES WILL DROP TO AROUND 40 ACROSS OUR CWA AND THEN RISE TO AROUND 60 TOMORROW...EXCEPT AREAS NEAR LAKE MICHIGAN WILL BE COOLER. LONG TERM... WEDNESDAY NIGHT THROUGH NEXT TUESDAY...OVERALL...EXPECT A COOL AND GENERALLY DRY PATTERN TO DOMINATE THE PERIOD. WILL KEEP A CHANCE FOR SHOWERS IN LATE WEDNESDAY NIGHT AND THURSDAY AS ANOTHER COOL FRONT PASSES...BUT ONCE AGAIN WITH MOISTURE LIMITED AND A WEAK FRONT...DO NOT EXPECT MUCH RAIN. AFTER THURSDAY...HAVE KEPT THE FORECAST DRY AND COOL WITH TEMPS BELOW NORMAL. GFS OF RECENT HAS HAD POOR RUN TO RUN CONSISTENCY WHICH IS APPARENT IN MEX MOS FLUCTUATIONS IN BOTH TEMPS AND POPS. BUT BASIC UPPER AIR PATTERN OF A DEVELOPING TROF OVER THE CENTRAL CONUS BY EARLY NEXT WEEK ALONG WITH A STRONG SFC RIDGE OVER CENTRAL CANADA IS PREEMINENT. EARLIER RUNS OF THE GFS WAS SUGGESTING A SURFACE WAVE WOULD SPREAD AT LEAST SOME PRECIPITATION OVER THE SOUTHERN PART OF THE AREA THIS WEEKEND...BUT GIVEN DOMINANT NORTH TO NORTHEAST SFC FLOW AND RUN TO RUN INCONSISTENCIES OF THE GFS AND ALSO TREND OF THE GFS TO OVER FORECAST PRECIPITATION IN THE NORTHERN PART OF STORM SYSTEM WHEN THERE IS A LOT OF DRY AIR ADVECTING IN THE LOWER LAYERS...HAVE KEEP THE FORECAST DRY. 12Z GFS SHOWED VERY COOL TEMPS SATURDAY THROUGH TUESDAY OF -4C OR COLDER AT 850 MB. HAVE HIGH BASICALLY 45 TO 50 THROUGH THE PERIOD TO MATCH THESE COOL TEMPS. 12Z GFS EXTENDED WAS EVEN SLOWER WITH MAJOR TROF EJECTING OUT OF THE PLAINS EARLY NEXT WEEK. GFS RUN FROM LAST NIGHT WAS BRINGING PRECIPITATION IN MONDAY...BUT NEW 12Z RUN WAS DRY THROUGH TUESDAY. GIVEN TENDENCY FOR GFS TO BE TOO FAST WITH HIGHLY AMPLIFIED SYSTEMS HAVE OPTED TO KEEP TUESDAY DRY AS THIS REASONING SUGGESTS BEST CHANCE OF RAIN WOULD BE AFTER TUESDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. && $$ in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 146 AM MDT WED APR 7 2004 .DISCUSSION...FORECAST PROBLEMS WILL BE TIMING OF PRECIPITATION AND THE HIGH TEMPERATURES THROUGH THE PERIOD. SATELLITE SHOWING A BROAD UPPER TROUGH OVER THE CENTRAL AND EASTERN PACIFIC WHICH IS BEING ACHORED BY LOW IN THE GULF OF ALASKA. RIDGING TO THE EAST OF THIS TROUGH IS SHOVING NEXT SYSTEM TOWARD THE DESERT SOUTHWEST. UPPER SYSTEM OVER TEXAS AND OKLAHOMA IS MAKING SLOW PROGRESS TOWARD THE EAST. ONE SHORTWAVE MOVING TOWARD THE GREAT LAKES WILL PUSH ANOTHER WEAK COLD FRONT ACROSS OUR AREA TODAY. DUE TO MODEL GRAPHIC DATA PROBLEMS WILL BE USING THE UKMET AND RUC FOR THIS PACKAGE. FOR TODAY/TONIGHT...PRECIPITATION HAS ENDED OVER THE AREA. PRECIPITATION FORMED IN DEFORMATION ZONE TO THE NORTH OF SOUTHERN PLAINS LOW. ALREADY RECEIVED A REPORT OF 1.3 INCHES OF RAINFALL FROM THE NORTHEAST PORTION OF FORECAST AREA. SATELLITE AND UPPER AIR ANALYSIS INDICATE DRIER AIR UPSTREAM AS RIDGING PUSHES IN BEHIND EXITING SYSTEM. SHORTWAVE SEEN UPSTREAM IS PRODUCING MID CLOUDS WITH A LITTLE LIGHT PRECIP/SPRINKLES. THE RUC CATCHES THIS AREA NICELY AND WEAKENS IT AS IT GETS CLOSER. FRONTAL PUSH DOES NOT LOOK TO BE THAT STRONG AS WELL. WILL GET DOWNSLOPING WIND IN ADVANCE OF BOUNDARY PLUS LOWER DEWPOINTS WILL BE BROUGHT IN BEHIND FRONT. THE BEST CHANCE FOR PRECIPITATION LOOKS TO BE OVER COLORADO WHERE THE UPSLOPE AND DYNAMICS ARE THE BEST. WILL ONLY HAVE ISOLATED SHOWERS FOR TODAY WITH LINGERING PRECIPITATION EARLY THIS EVENING OVER SOUTHERN AND SOUTHWEST SECTIONS. THEN SHOULD HAVE SOME PATCHY FOG DUE TO SOME UPSLOPE AND POSSIBLY WET GROUND. FOR TODAY WILL HAVE PATCHY FOG EARLY. CLOUDS SHOULD CLEAR OUT EARLY AND WILL HAVE DOWNSLOPE AND ENOUGH SUN TO ALLOW MAXES TO BE THE WARMEST THEY WILL BE FOR A FEW DAYS. DOES NOT LOOK TO BE A LOT OF COOLING WITH THIS FRONT WITH 850 MB ANALYSIS SHOWING LITTLE DROP OFF ON TEMPS BEHIND IT. TEMPERATURES ARE ALSO WARMER IN MONTANA THAN PORTIONS OF THE SOUTHERN PLAINS AT THIS TIME. PLAN ON GOING CLOSE TO THE WARMER GUIDANCE. FOR THURSDAY INTO FRIDAY...NEXT SHORTAVE STARTS MOVING INTO AREA THURSDAY AFTERNOON. WILL ALSO HAVE DECENT EASTERLY UPSLOPE WINDS FEEDING MOISTURE INTO THIS SYSTEM. SHORTWAVE LOOKS TO TAKE ON A LITTLE NEGATIVE TILT. PRECIPITATION SHOULD BECOME WIDESPREAD THURSDAY NIGHT AND CONTINUE INTO FRIDAY. ALSO LOOK TO HAVE DECENT WARM AIR ADVECTION/UPGLIDE OVER THE TOP OF THE COLD DOME THROUGH THIS ENTIRE TIME. THEN NEXT SHORTWAVE MOVES IN LATE FRIDAY. WILL START OUT WITH A SLIGHT CHANCE IN THE WEST ON THURSDAY. THEN WILL HAVE HIGH CHANCE TO LIKELY THURSDAY NIGHT AND FRIDAY. WITH EVERYTHING POINTING TO NOT MUCH WARMING OCCURING DURING BOTH DAYS... WILL GO NEAR TO SLIGHTLY BELOW THE GUIDANCE. MINS THURSDAY NIGHT WILL BE MILD WITH CLOUDS...UPSLOPE...AND PRECIPITATION. FOR FRIDAY NIGHT THROUGH DAY 7...WITH MODEL DATA PROBLEMS WILL NOT BE UPDATING THIS PERIOD. CURRENT ZONES DO HAVE BOTH RAIN AND SNOW MENTIONED AND THAT LOOKS GOOD FOR NOW. DAY CREW WILL HAVE TO TAKE A CLOSER LOOK AT THIS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 559 AM EDT WED APR 7 2004 .UPDATE... 3.9U IMAGERY AND METARS SHOW LOW STRATUS DECK CONTINUES TO FILTER SOUTH. LATEST RUC/ETA SHOW THIS LAYER CONTINUING TO FILTER SOUTH WITH SOUTHERN EDGES BREAKING UP SOUTH OF THE ARB-DTW LINE. ZONE AND GRIDS UPDATE ACCOUNT FOR THIS WITH IMPROVEMENTS EXPECTED AROUND 15Z. && .DISCUSSION...ISSUED AT 315 AM EDT WEAK GRADIENT FLOW ACROSS EASTERN 2/3RDS OF THE CONUS PER LATEST SURFACE ANALYSIS. YESTERDAYS WEAK WAVE RESULTED WITH LITTLE IN THE RAIN ADDING IN THE BUCKET AS THIS WAVE CONTINUES TO WEAKEN AND PUSH OFFSHORE. FURTHER UPSTREAM, YET ANOTHER WAVE NOW MOVING INTO NORTH DAKOTA. THIS WAVE APPEARS TO BE PACKING A LITTLE MORE OF A PUNCH WITH H2O VAPOR REPRESENTATION INDICATING A SMALL COMMA HEAD AND SATELLITE DERIVED WINDS INDICATING JET COUPLING WITH 70-80 KNTS. THIS HAS RESULTED IN CONVECTION WITH LIGHTNING STRIKES JUST NORTH OF THE BORDER AS OF 06Z. INBETWEEN THESE SYSTEMS, HIGH PRESSURE WHICH WILL MOVE ACROSS THE STATE TODAY. INITIALIZATION WAS FAIRLY GOOD, ALTHOUGH, THE GFS APPEARS TO BE THE MODEL OF CHOICE AS WE LOOK FURTHER INTO THE FUTURE. TODAY... IN A NUTSHELL, AFOREMENTIONED SURFACE HIGH SLIDES ACROSS THE STATE TODAY WITH TRANQUIL CONDITIONS. BUT WE WILL NEED TO MONITOR STRATUS DECK WHICH IS PROGRESSING SOUTHEAST ACROSS SAGINAW BAY/THUMB WITH BORDERLINE MVFR/IFR CEILINGS. LATEST OPERATIONAL MESOSCALE MODELS ARE NOT HANDLING THIS WELL BUT TAQ RUC (EXPERIMENTAL) IS DOING BETTER WHICH BRINGS THE STRATUS DECK SOUTH ACROSS BAY, TUSCOLA, HURON, SANILAC AND PORTIONS OF ST CLAIR COUNTY BEFORE MIXING OUT AROUND 15Z. OUTSIDE OF THIS, SKIES TODAY SHOULD BE MOSTLY SUNNY. SOME HIGH/MID LEVEL MOISTURE FROM UPPER LOW OVER THE SOUTHERN PLAINS AND APPROACH OF UPSTREAM WAVE MAY BRING MORE CLOUDS THIS AFTERNOON...BUT FOR MOST PEOPLE IT SHOULD A MORE SUN THAN CLOUDS DAY. BASED ON UPSTREAM TEMPS WHICH WERE IN THE UPPER 60S AND LOWER 70S...FOLLOWING THOSE THICKNESSES WOULD TAKE MOST OF THIS SPRINGLIKE AIR SOUTH INTO THE OHIO VALLEY. WITH SURFACE HIGH MOVING ACROSS, GRADIENT WILL BE LIGHT TO MINIMIZE MIXING WHICH WOULD SUPPORT MID 50S AWAY FROM THE WATER. IT WILL BE A BIT COOLER NEAR THE LAKES AS LOCAL CHARTS SHOW LAKE BREEZES SETTING UP EARLY THIS AFTERNOON WITH LIGHT 925/950MB WINDS. TONIGHT... LAKE BREEZE ACTIVITY WILL ABATE THIS EVENING AS UPSTREAM WAVE BEGINS IT APPROACH ON THE GREAT LAKES REGION. AT THIS POINT, MODELS DO DIVERGE WITH RESPECT TO PLACEMENT OF LIFT, MOISTURE AND UPPER LEVEL SUPPORT. GIVEN UPSTREAM SPEED OF THIS SYSTEM, WE WOULD HAVE TO FAVOR THE GFS TIMING. THIS IS IN AGREEMENT WITH THE UKMET AND TAQ RUC WHICH BRINGS US TO ADD PRECIP TO THE GRIDS LATE TONIGHT. Q-VECTOR CONVERGENCE IS IMPRESSIVE AND COINCIDES WITH OMEGA PATTERN LATE TONIGHT FOR SCATTERED POPS IN THE GRIDS. WITH THE INCREASE IN THE CLOUD COVER, TEMPERATURES WILL HOLD UP A BIT INTO THE MID-UPPER 30S. THURSDAY... WE SHOULD START THE DAY WITH SCATTERED SHOWERS AS Q-VECTOR CONVERGENCE/OMEGA AND DIVERGENCE ALOFT SLIDE TO THE EAST BY LATE MORNING. SURFACE FEATURES WILL BE TOUGH TO PIN DOWN WITH WEAK LOW PASSING ACROSS THE LOWER HALF OF THE STATE LEAVING BEHIND SURFACE TROF/COLD FRONT ACROSS THE REGION. HERE IS WHERE SOME MAJOR DIFFERENCES OCCUR AS THE ETA SWINGS A DRY SLOT ACROSS THE SOUTHERN COUNTIES WHILE THE GFS IS FURTHER SOUTH INTO THE OHIO VALLEY. THIS WOULD AGREE WITH THE UKMET AND TAQ RUC TO KEEP THE CLOUDS AND THE CHANCE FOR LIGHT SHOWER ACTIVITY FOR THE REMAINDER OF THE DAY. WITH THE EXPECTED CLOUD COVER AND PRECIP, WE WILL NEED TO BRING DOWN OUR EXPECTED MAX TEMPS A BIT WITH THE HIGHER VALUES POSSIBLE FROM ARB-DTW SOUTHWARD. THURSDAY NIGHT... THIS CAN PROVE TO BE THE MOST CHALLENGING ASPECT OF THE FORECAST AND WILL LIKELY CHANGE. LATEST GUIDANCE NOW POINTS TOWARD SHORT WAVE TROF TO MOVE SOUTHEAST ACROSS THE CWA PUSHING SURFACE COLD FRONT SOUTH. MOISTURE COLUMN IS MORE MOIST THIS RUN WITH GFS OMEGA FIELDS FOCUSING ACROSS THE NORTHERN HALF OF THE CWA. WITH SOME SURFACE CONVERGENCE AND THE CHANCE FOR SOME MID LEVEL WAVE AFFECTING THE NORTHWEST FLOW REGIME, WE WILL BRING IN A CHANCE FOR A RAIN/SNOW MIX NORTH WHERE THICKNESSES AND SOUNDINGS ARE BORDERLINE...AND A BIT WARMER SOUTH FOR PRIMARILY RAIN. AGAIN, CONFIDENCE IN THIS SOLUTION IS POOR AND WILL LIKELY BE MODIFIED. FRIDAY... WE FIND OURSELVES BETWEEN SYSTEMS WITH WEAK SHORT WAVE RIDGE IN PLACE. WE WILL CONTINUE WITH THE DRY FORECAST BUT KEEP THE CLOUD FESTIVAL GOING. TEMPERATURES WILL GENERALLY RANGE BETWEEN 45 AND 50 FROM NORTH TO SOUTH. LOOKING AHEAD OFFERS TOO MANY CHALLENGES TO MENTION. HOWEVER, IN SUMMARY THE 00Z GUIDANCE TAKES GULF LOW AND TRACKS THIS SYSTEM SOUTHEAST OF THE REGION AND AFFECT THE EAST COAST. THIS IS SUPPORTED BY THE 00Z CANADIAN WHICH KEEPS THE CWA UNDER HIGHER SURFACE PRESSURES BUT TROFINESS ALOFT. THANKS TO THE SURROUNDING OFFICES AND HPC FOR THE COLLABORATION! && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BGM EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 355 AM EDT WED APR 7 2004 .DISCUSSION... MAIN FORECAST CONCERN IS PRECIPITATION TONIGHT. CURRENT WEATHER...07Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED NW FLOW ACROSS THE NORTH HALF OF NORTH AMERICA...WITH A RIDGE IN WESTERN CANADA AND A TROUGH OVER THE CANADIAN MARITIMES. THE MAIN FEATURE WITHIN THE NW FLOW THAT WILL AFFECT UPPER MICHIGAN WAS A SHRTWV LOCATED NEAR MINOT NORTH DAKOTA. THIS SHRTWV...WITH 500MB TEMPS OF -26 TO -28C AND 700-500MB LAPSE RATES OF 7.5C/KM WITH IT PER DERIVED DATA FROM THE RUC...HAS AIDED IN THE DEVELOPMENT OF SOME -TSRA OVER SE SASKATCHEWAN. 00Z RAOBS SHOWED A DEVELOPING BAROCLINIC ZONE AT 850MB WITH THE NORTH DAKOTA SHRTWV...WITH TEMPS OF +2C AT CALGARY ALBERTA AND +12C AT GLASGOW MONTANA. ASSOCIATED WITH THE BAROCLINIC ZONE WAS AN 80 KT WESTERLY JET AT 250MB NEAR MINOT (AGAIN OBSERVED AT 00Z) WITH A 90 KT NORTHWEST JET MOVING THROUGH CALGARY. UPPER DIVERGENCE IN THE RIGHT ENTRANCE REGION REFLECTED AT THE SURFACE WITH PRESSURE FALLS OVER NORTH DAKOTA. AT THE SURFACE...HIGH PRESSURE WAS LOCATED OVER NORTHERN WISCONSIN. 11-3.9 UM SATELLITE IMAGERY SHOWED CLEAR SKIES WITH THE HIGH...ALLOWING TEMPERATURES TO FALL INTO THE 30S. THE EXCEPTION IS ALONG THE KEWEENAW PENINSULA WHERE TEMPS REMAIN IN THE MID 40S BECAUSE OF WINDS STAYING UP THERE. LIGHT WINDS OVER THE REST OF THE FORECAST AREA AND CLEAR SKEIS HAS ALLOWED SOME PATCHY FOG TO FORM. THE EXCEPTION TO THE CLEAR SKIES IS OVER EASTERN UPPER MICHIGAN WHERE LAKE STRATUS CLOUDS THAT FORMED YESTERDAY REMAIN. TODAY...DEVELOPING SURFACE LOW OVER THE DAKOTAS IS PROGGED TO HEAD TO THE EAST...REACHING NW WISCONSIN BY 00Z. AHEAD OF THE LOW...HIGH CLOUDS WILL INCREASE ACROSS UPPER MICHIGAN...WHICH CAN ALREADY BE SEEN MOVING THROUGH NORTH DAKOTA AND NORTHERN MN. SOLAR INSOLATION WILL BE SOMEWHAT LIMITED BY THE HIGH CLOUDS...BUT SHOULD STILL BE STRONG ENOUGH TO MIX OUT ANY PATCHY FOG THIS MORNING. ANY PRECIPIATION ASSOCIATED WITH THE SHRTWV APPEARS TO HOLD OFF AT LEAST UNTIL EVENING...ESPECIALLY GIVEN THE DRY AIR MASS SEEN ON THE 00Z GRB AND MPX SOUNDINGS. TEMPS A LITTLE MORE TRICKY NOW THAT THE SUNLIGHT IS MUCH STRONGER. THIS IS REFLECTED IN MAV GUIDANCE ALONG THE WISCONSIN BORDER SHOWING TEMPS IN THE LOW 50S. LOOKING AT 850MB TEMPS...ETA NEVER SHOWS THEM DROPPING BELOW +2C OVER THE CWA. THEREFORE...WILL UP TEMPS A DEGREE OR TWO. WITH A WEAK PRESSURE GRADIENT...WOULD NOT BE SURPRISED TO SEE LAKE BREEZES SET UP AGAIN. TONIGHT...SFC LOW AND SHRTWV PASSES ACROSS THE CITY OF GREEN BAY INTO WESTERN LOWER MI BY 12Z THU PER ETA/GFS. BY THIS TIME ENOUGH MOISTURE ADVECTION WILL HAVE OCCURRED TO BRING A BAND OF PRECIPITATION INTO THE CWA AHEAD OF THE SFC LOW. HAVE ALSO ADDED THE MENTION OF TS AFTER NOTICING THE POCKET OF STEEP 700-500MB LAPSE RATES AND SHOWALTER INDICES AROUND 0C MOVE OVER THE WEST HALF OF UPPER MI ACCORDING TO THE ETA. BOTH THE GFS AND ETA INDICATE AN INVERTED TROUGH EXTENDING BACK INTO WESTERN LAKE SUPERIOR AS THE SFC LOW MOVES INTO LOWER MI...WHICH WILL BE USED AS A FORCING MECHANISM FOR MORE PRECIPITATION. ANOTHER AID TO THE FORCING WILL BE UPPER DIVERGENCE IN THE LEFT EXIT REGION OF A 100 KT JET OVER WISCONSIN (THE JET CURRENTLY OVER CALGARY). AS FOR TYPE...IT APPEARS THAT THERE WILL BE ENOUGH WARM AIR TO KEEP THINGS AS RAIN IN THE EVENING...BUT AS COLDER AIR IS ADVECTED IN FROM THE WEST AND NORTH...THE PRECIPITATION WILL CHANGE OVER TO SNOW. WILL MODIFY THE WX GRIDS TO REFLECT TIMING AND ORIENTATION OF THE PRECIPTATION. AS FOR LOWS...CLOUD COVER WILL HELP KEEP TEMPS UP HOWEVER COLD AIR ADVECTION AS MENTIONED ABOVE WILL BRING TEMPS DOWN WITH THE PASSING OF THE LOW. WILL USE MAV GUIDANCE FOR LOWS. THURSDAY...INVERTED TROUGH SAGS SOUTHWARD ACROSS UPPER MICHIGAN AS 500MB AND 850MB FLOW BECOMES MORE NORTHERLY AND THE SFC LOW MOVES TOWARDS NEW YORK. THE NORTHERLY FLOW WILL DROP 850MB TEMPS TO -4 TO -6C BY 21Z. SO TEMPS WILL DEFINITELY BE COOLER THAN TODAY...IN THE MID 30S. ALONG WITH THE COLD ADVECTION...SNOW WILL BE OCCURRING IN THE MORNING ALONG THE INVERTED TROUGH. EXPECTING THE SNOW TO DIMINISH DURING THE AFTERNOON AS MUCH OF THE DYNAMICS HEAD OFF TO THE EAST AND DRY AIR GETS ADVECTED IN FROM THE NORTH. THURSDAY NIGHT AND FRIDAY...AS A BROAD 500MB TROUGH FORMES OVER NEW ENGLAND...COLD AIR ADVECTION CONTINUES UNDER NORTHERLY FLOW...WITH 850MB TEMPS FALLING TO -10 TO -12C BY 12Z FRI AND THEN REMAINING STEADY THROUGH 00Z SAT. GFS IS A FEW DEGREES COLDER...BUT WITH ITS LOW BIAS...TEND TO BELIEVE THE ETA MORE. LACK OF ANY FORCING IN THE COLD ADVECTION REGIME PRECLUDES ANY MENTIONING OF PRECIPITATION. DESPITE THE COOLING IN 850MB TEMPS...LAKE EFFECT POTENTIAL SEEMS MINIMAL TOO WITH DELTA-T/S AROUND 13C AND INVERSION HEIGHTS SITTING BETWEEN 3000 AND 4000 FT. BEST LOCATION OF SEEING ANY FLURRIES OR SNOW SHOWERS WOULD OCCUR OVER THE NORTH CENTRAL U.P. WHERE THE NORTHERLY SURFACE WINDS UPSLOPE. ONLY ADJUSTMENT WILL BE TO LOWER POPS ON FRIDAY AS OVERALL SETUP DOES NOT LOOK FAVORABLE FOR SNOW. $$ && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 315 AM EDT WED APR 7 2004 .DISCUSSION... WEAK GRADIENT FLOW ACROSS EASTERN 2/3RDS OF THE CONUS PER LATEST SURFACE ANALYSIS. YESTERDAYS WEAK WAVE RESULTED WITH LITTLE IN THE RAIN ADDING IN THE BUCKET AS THIS WAVE CONTINUES TO WEAKEN AND PUSH OFFSHORE. FURTHER UPSTREAM, YET ANOTHER WAVE NOW MOVING INTO NORTH DAKOTA. THIS WAVE APPEARS TO BE PACKING A LITTLE MORE OF A PUNCH WITH H2O VAPOR REPRESENTATION INDICATING A SMALL COMMA HEAD AND SATELLITE DERIVED WINDS INDICATING JET COUPLING WITH 70-80 KNTS. THIS HAS RESULTED IN CONVECTION WITH LIGHTNING STRIKES JUST NORTH OF THE BORDER AS OF 06Z. INBETWEEN THESE SYSTEMS, HIGH PRESSURE WHICH WILL MOVE ACROSS THE STATE TODAY. INITIALIZATION WAS FAIRLY GOOD, ALTHOUGH, THE GFS APPEARS TO BE THE MODEL OF CHOICE AS WE LOOK FURTHER INTO THE FUTURE. TODAY... IN A NUTSHELL, AFOREMENTIONED SURFACE HIGH SLIDES ACROSS THE STATE TODAY WITH TRANQUIL CONDITIONS. BUT WE WILL NEED TO MONITOR STRATUS DECK WHICH IS PROGRESSING SOUTHEAST ACROSS SAGINAW BAY/THUMB WITH BORDERLINE MVFR/IFR CEILINGS. LATEST OPERATIONAL MESOSCALE MODELS ARE NOT HANDLING THIS WELL BUT TAQ RUC (EXPERIMENTAL) IS DOING BETTER WHICH BRINGS THE STRATUS DECK SOUTH ACROSS BAY, TUSCOLA, HURON, SANILAC AND PORTIONS OF ST CLAIR COUNTY BEFORE MIXING OUT AROUND 15Z. OUTSIDE OF THIS, SKIES TODAY SHOULD BE MOSTLY SUNNY. SOME HIGH/MID LEVEL MOISTURE FROM UPPER LOW OVER THE SOUTHERN PLAINS AND APPROACH OF UPSTREAM WAVE MAY BRING MORE CLOUDS THIS AFTERNOON...BUT FOR MOST PEOPLE IT SHOULD A MORE SUN THAN CLOUDS DAY. BASED ON UPSTREAM TEMPS WHICH WERE IN THE UPPER 60S AND LOWER 70S...FOLLOWING THOSE THICKNESSES WOULD TAKE MOST OF THIS SPRINGLIKE AIR SOUTH INTO THE OHIO VALLEY. WITH SURFACE HIGH MOVING ACROSS, GRADIENT WILL BE LIGHT TO MINIMIZE MIXING WHICH WOULD SUPPORT MID 50S AWAY FROM THE WATER. IT WILL BE A BIT COOLER NEAR THE LAKES AS LOCAL CHARTS SHOW LAKE BREEZES SETTING UP EARLY THIS AFTERNOON WITH LIGHT 925/950MB WINDS. TONIGHT... LAKE BREEZE ACTIVITY WILL ABATE THIS EVENING AS UPSTREAM WAVE BEGINS IT APPROACH ON THE GREAT LAKES REGION. AT THIS POINT, MODELS DO DIVERGE WITH RESPECT TO PLACEMENT OF LIFT, MOISTURE AND UPPER LEVEL SUPPORT. GIVEN UPSTREAM SPEED OF THIS SYSTEM, WE WOULD HAVE TO FAVOR THE GFS TIMING. THIS IS IN AGREEMENT WITH THE UKMET AND TAQ RUC WHICH BRINGS US TO ADD PRECIP TO THE GRIDS LATE TONIGHT. Q-VECTOR CONVERGENCE IS IMPRESSIVE AND COINCIDES WITH OMEGA PATTERN LATE TONIGHT FOR SCATTERED POPS IN THE GRIDS. WITH THE INCREASE IN THE CLOUD COVER, TEMPERATURES WILL HOLD UP A BIT INTO THE MID-UPPER 30S. THURSDAY... WE SHOULD START THE DAY WITH SCATTERED SHOWERS AS Q-VECTOR CONVERGENCE/OMEGA AND DIVERGENCE ALOFT SLIDE TO THE EAST BY LATE MORNING. SURFACE FEATURES WILL BE TOUGH TO PIN DOWN WITH WEAK LOW PASSING ACROSS THE LOWER HALF OF THE STATE LEAVING BEHIND SURFACE TROF/COLD FRONT ACROSS THE REGION. HERE IS WHERE SOME MAJOR DIFFERENCES OCCUR AS THE ETA SWINGS A DRY SLOT ACROSS THE SOUTHERN COUNTIES WHILE THE GFS IS FURTHER SOUTH INTO THE OHIO VALLEY. THIS WOULD AGREE WITH THE UKMET AND TAQ RUC TO KEEP THE CLOUDS AND THE CHANCE FOR LIGHT SHOWER ACTIVITY FOR THE REMAINDER OF THE DAY. WITH THE EXPECTED CLOUD COVER AND PRECIP, WE WILL NEED TO BRING DOWN OUR EXPECTED MAX TEMPS A BIT WITH THE HIGHER VALUES POSSIBLE FROM ARB-DTW SOUTHWARD. THURSDAY NIGHT... THIS CAN PROVE TO BE THE MOST CHALLENGING ASPECT OF THE FORECAST AND WILL LIKELY CHANGE. LATEST GUIDANCE NOW POINTS TOWARD SHORT WAVE TROF TO MOVE SOUTHEAST ACROSS THE CWA PUSHING SURFACE COLD FRONT SOUTH. MOISTURE COLUMN IS MORE MOIST THIS RUN WITH GFS OMEGA FIELDS FOCUSING ACROSS THE NORTHERN HALF OF THE CWA. WITH SOME SURFACE CONVERGENCE AND THE CHANCE FOR SOME MID LEVEL WAVE AFFECTING THE NORTHWEST FLOW REGIME, WE WILL BRING IN A CHANCE FOR A RAIN/SNOW MIX NORTH WHERE THICKNESSES AND SOUNDINGS ARE BORDERLINE...AND A BIT WARMER SOUTH FOR PRIMARILY RAIN. AGAIN, CONFIDENCE IN THIS SOLUTION IS POOR AND WILL LIKELY BE MODIFIED. FRIDAY... WE FIND OURSELVES BETWEEN SYSTEMS WITH WEAK SHORT WAVE RIDGE IN PLACE. WE WILL CONTINUE WITH THE DRY FORECAST BUT KEEP THE CLOUD FESTIVAL GOING. TEMPERATURES WILL GENERALLY RANGE BETWEEN 45 AND 50 FROM NORTH TO SOUTH. LOOKING AHEAD OFFERS TOO MANY CHALLENGES TO MENTION. HOWEVER, IN SUMMARY THE 00Z GUIDANCE TAKES GULF LOW AND TRACKS THIS SYSTEM SOUTHEAST OF THE REGION AND AFFECT THE EAST COAST. THIS IS SUPPORTED BY THE 00Z CANADIAN WHICH KEEPS THE CWA UNDER HIGHER SURFACE PRESSURES BUT TROFINESS ALOFT. THANKS TO THE SURROUNDING OFFICES AND HPC FOR THE COLLABORATION! && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BGM EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 400 AM CST WED APR 7 2004 .SHORT TERM...SERIES OF SHRTWVS MV OVR CENTRAL TX THRU SAT...WITH SCT SHRAS/TSRAS THU AS SRN STREAM MIGRATES NORTH TO RGV BY 18Z THU. TEMPS IN THE 80S BY DAY...NEAR 70 BY NIGHT...WITH PATCHY MRNG FG. SFC WNDS LIGHT AND VARIABLE UNTIL SAT...THEN LIGHT SE. SUN THRU TUE IS OUR MAIN CONCERN NOW. && .LONG TERM...A COLD FRONT WILL MOVE THROUGH DEEP SOUTH TEXAS EARLY SUNDAY MORNING. AS THE FRONT APPROACHES THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE SATURDAY NIGHT INTO SUNDAY. CURRENT LONG RANGE MDLS AGREE ON THIS FRONTAL PASSAGE...AND THE HVY RAFL THAT CUD ACCOMPANY THIS FEATURE...ALONG WITH STRONG TSTM DEVELOPMENT. AN ALREADY SATURATED RGV WILL NEED TO WATCH FLOOD POTENTIAL SUNDAY. COOL MRNG TEMPS TO THE UPPER 40S WEST FOR MON AND TUE. .MARINE...MSAS SURFACE ANALYSIS INDICATES LIGHT SOUTHEAST FETCH ACROSS THE WESTERN GULF OF MEXICO. SEAS 5 FEET WITH EAST WINDS NEAR 5 KNOTS AT BUOY020 THIS MORNING. EXPECT LIGHT WINDS THIS AFTERNOON WITH A SURFACE TROUGH DRAPED ACROSS SOUTH TEXAS. LIGHT SOUTHEAST WINDS TO PREVAIL THURSDAY WITH LOW PRESSURE OVER NORTHEAST MEXICO AND WEAK HIGH PRESSURE RIDGE OVER CENTRAL TX. A FEW SHOWERS MAY DEVELOP ACROSS THE COASTAL WATERS THURS AFTERNOON WITH A 500MB VORTICITY MAXIMUM CENTER ACROSS THE UPPER VALLEY INCREASING POSITIVE VORTICITY ADVECTION ACROSS THE LOWER TX COAST. PRESSURE GRADIENT EXPECTED TO INCREASE FRIDAY WITH LOW PRESSURE DEVELOPING OVER THE TX PANHANDLE. SMALL CRAFT ADVISORIES MAY BE NEEDED FRI NIGHT OFFSHORE. WEAK COLD FRONT PROGGED TO MOVE THROUGH CENTRAL TX SATURDAY MORNING AND REACH DEEP SOUTH TX SAT NIGHT. WINDS WILL DECREASE SAT AFTERNOON AND SHIFT TO THE NORTHEAST AND INCREASE SAT NIGHT. IN ADDITION...SHOWERS AND THUNDERSTORMS WILL DEVELOP AS THE FRONT APPROACHES THE LOWER TX COAST. LATEST GFS RUN PROGS A CONVECTIVE COMPLEX DEVELOPING ACROSS THE LOWER RIO GRANDE VALLEY LATE SATURDAY INTO EARLY SUNDAY AND MOVING EASTWARD SUN MORNING. STRONG NORTH WINDS PROGGED TO DEVELOP IN THE WAKE OF THE CONVECTION WITH A TIGHT PRESSURE GRADIENT OFFSHORE. SMALL CRAFT ADVISORIES WILL BE NEEDED WITH GUSTS TO NEAR GALE FORCE POSSIBLE. && .AVIATION...LOW STRATUS DECK ACROSS THE LOWER RIO GRANDE VALLEY WITH CEILINGS NEAR 500 FEET. KHRL REPORTING REDUCED VISIBLY WITH FOG. BELIEVE FOG WILL CONTINUE TO DEVELOP THIS MORNING WITH LIGHT WINDS. WATER VAPOR SATELLITE IMAGES AND RUC 500MB HEIGHT/VORTICITY ANALYSIS INDICATES WEAK SHORTWAVE TROUGH MOVING ACROSS NORTHEAST MEXICO. PVA ASSOCIATED WITH THIS SHORTWAVE MAY INITIATE SHOWERS ACROSS THE LOWER VALLEY LATER THIS MORNING. CEILINGS EXPECTED TO IMPROVE LATER THIS MORNING WITH SOUTH WINDS BRINGING DRIER AIR FROM THE MEXICAN INTERIOR. MVFR TO IFR CONDITIONS TO PREVAIL TONIGHT WITH STRATUS DECK DEVELOPING WITH MOIST BOUNDARY LAYER. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 84 71 80 72 84/ 00 00 10 10 00 BROWNSVILLE 85 70 81 70 86/ 00 00 10 10 00 HARLINGEN 86 69 84 69 87/ 00 00 00 10 00 MCALLEN 88 69 85 68 89/ 00 00 20 20 00 RIO GRANDE CITY 89 67 85 68 89/ 00 00 20 20 00 SOUTH PADRE ISLAND 81 72 79 72 81/ 00 00 10 10 00 && .BRO WATCHES/WARNINGS/ADVISORIES...FLOOD WARNING FOR THE RIO GRANDE RIVER IN ZAPATA COUNTY. $$ 58/61 THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PEACHTREE CITY GA 1110 AM EDT WED APR 7 2004 .UPDATE... UPPER LOW CURRENTLY ROTATING OVER NORTH TEXAS WITH WEAK IMPULSES MOVING ACROSS THE GULF COAST STATES. LATEST RUC INDICATES UPPER LOW WILL WEAKEN AS IT MOVES EAST THIS EVENING. CONVECTION LOCATED OVER THE NORTHEAST GULF WILL LIFT NORTHEAST THIS AFTERNOON...INSTABILITY IS MINIMAL AS SHOWERS APPROACH...BUT ENOUGH TO WARRANT ISOLATED THUNDER THIS EVENING. HAVE DROPPED POPS FOR 2ND PERIOD TO HIGH CHANCE AS EXPECT MORE SCATTERED TYPE ACTIVITY. CURRENT FORECAST ON TRACK A FAR AS AFTERNOON HIGHS...SO NO CHANGES PLANNED TO TEMPERATURES. && .ATL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 909 AM MDT WED APR 7 2004 .UPDATE... WEAK COLD FRONT/WIND SHIFT TO ENTER NORTHERN FORECAST AREA THIS AFTERNOON. CONVECTIVE PARAMETERS WILL BE MARGINAL WITH PRIMARY LIMITING FACTORS CAPE < 200 J/KG AND WEAK LAPSE RATES. HOWEVER THERE APPEARS TO BE JUST ENOUGH MOISTURE AVAILABLE TO SUPPORT ISOLATED THUNDER AS LOW LEVEL CONVERGENCE ALONG THE FRONT RUNS INTO THE AVAILABLE MOISTURE AT THE TIME OF PEAK DAYTIME HEATING. FRONT WILL STEADILY MARCH SOUTH THROUGH THE CENTRAL AND SOUTHERN FORECAST AREA THIS EVENING...EXITING TO THE SOUTH BY 06Z. /JDK .PREV DISCUSSION... 146 AM MDT WED APR 7 2004 FORECAST PROBLEMS WILL BE TIMING OF PRECIPITATION AND THE HIGH TEMPERATURES THROUGH THE PERIOD. SATELLITE SHOWING A BROAD UPPER TROUGH OVER THE CENTRAL AND EASTERN PACIFIC WHICH IS BEING ACHORED BY LOW IN THE GULF OF ALASKA. RIDGING TO THE EAST OF THIS TROUGH IS SHOVING NEXT SYSTEM TOWARD THE DESERT SOUTHWEST. UPPER SYSTEM OVER TEXAS AND OKLAHOMA IS MAKING SLOW PROGRESS TOWARD THE EAST. ONE SHORTWAVE MOVING TOWARD THE GREAT LAKES WILL PUSH ANOTHER WEAK COLD FRONT ACROSS OUR AREA TODAY. DUE TO MODEL GRAPHIC DATA PROBLEMS WILL BE USING THE UKMET AND RUC FOR THIS PACKAGE. FOR TODAY/TONIGHT...PRECIPITATION HAS ENDED OVER THE AREA. PRECIPITATION FORMED IN DEFORMATION ZONE TO THE NORTH OF SOUTHERN PLAINS LOW. ALREADY RECEIVED A REPORT OF 1.3 INCHES OF RAINFALL FROM THE NORTHEAST PORTION OF FORECAST AREA. SATELLITE AND UPPER AIR ANALYSIS INDICATE DRIER AIR UPSTREAM AS RIDGING PUSHES IN BEHIND EXITING SYSTEM. SHORTWAVE SEEN UPSTREAM IS PRODUCING MID CLOUDS WITH A LITTLE LIGHT PRECIP/SPRINKLES. THE RUC CATCHES THIS AREA NICELY AND WEAKENS IT AS IT GETS CLOSER. FRONTAL PUSH DOES NOT LOOK TO BE THAT STRONG AS WELL. WILL GET DOWNSLOPING WIND IN ADVANCE OF BOUNDARY PLUS LOWER DEWPOINTS WILL BE BROUGHT IN BEHIND FRONT. THE BEST CHANCE FOR PRECIPITATION LOOKS TO BE OVER COLORADO WHERE THE UPSLOPE AND DYNAMICS ARE THE BEST. WILL ONLY HAVE ISOLATED SHOWERS FOR TODAY WITH LINGERING PRECIPITATION EARLY THIS EVENING OVER SOUTHERN AND SOUTHWEST SECTIONS. THEN SHOULD HAVE SOME PATCHY FOG DUE TO SOME UPSLOPE AND POSSIBLY WET GROUND. FOR TODAY WILL HAVE PATCHY FOG EARLY. CLOUDS SHOULD CLEAR OUT EARLY AND WILL HAVE DOWNSLOPE AND ENOUGH SUN TO ALLOW MAXES TO BE THE WARMEST THEY WILL BE FOR A FEW DAYS. DOES NOT LOOK TO BE A LOT OF COOLING WITH THIS FRONT WITH 850 MB ANALYSIS SHOWING LITTLE DROP OFF ON TEMPS BEHIND IT. TEMPERATURES ARE ALSO WARMER IN MONTANA THAN PORTIONS OF THE SOUTHERN PLAINS AT THIS TIME. PLAN ON GOING CLOSE TO THE WARMER GUIDANCE. FOR THURSDAY INTO FRIDAY...NEXT SHORTAVE STARTS MOVING INTO AREA THURSDAY AFTERNOON. WILL ALSO HAVE DECENT EASTERLY UPSLOPE WINDS FEEDING MOISTURE INTO THIS SYSTEM. SHORTWAVE LOOKS TO TAKE ON A LITTLE NEGATIVE TILT. PRECIPITATION SHOULD BECOME WIDESPREAD THURSDAY NIGHT AND CONTINUE INTO FRIDAY. ALSO LOOK TO HAVE DECENT WARM AIR ADVECTION/UPGLIDE OVER THE TOP OF THE COLD DOME THROUGH THIS ENTIRE TIME. THEN NEXT SHORTWAVE MOVES IN LATE FRIDAY. WILL START OUT WITH A SLIGHT CHANCE IN THE WEST ON THURSDAY. THEN WILL HAVE HIGH CHANCE TO LIKELY THURSDAY NIGHT AND FRIDAY. WITH EVERYTHING POINTING TO NOT MUCH WARMING OCCURING DURING BOTH DAYS... WILL GO NEAR TO SLIGHTLY BELOW THE GUIDANCE. MINS THURSDAY NIGHT WILL BE MILD WITH CLOUDS...UPSLOPE...AND PRECIPITATION. FOR FRIDAY NIGHT THROUGH DAY 7...WITH MODEL DATA PROBLEMS WILL NOT BE UPDATING THIS PERIOD. CURRENT ZONES DO HAVE BOTH RAIN AND SNOW MENTIONED AND THAT LOOKS GOOD FOR NOW. DAY CREW WILL HAVE TO TAKE A CLOSER LOOK AT THIS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI ISSUED BY NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1135 AM EDT WED APR 7 2004 .UPDATE... THE PRIMARY CHANGE WITH THE MORNING UPDATE WAS TO HOLD ONTO THE CLOUDS A LITTLE LONGER...MAINLY FOR THE NORTHEAST COUNTIES. I DO NOT BELIEVE THESE CLOUDS WILL IMPACT THE HIGH TEMPERATURES TODAY AS STRONG APRIL SUNSHINE SHOULD WARM THINGS UP INTO THE LOW TO MID 50S FOR MOST AREAS. AREAS NEAR LAKE HURON WILL CERTAINLY BE COOLER WITH AN EASTERLY COMPONENT TO THE THE WIND. && .DISCUSSION...ISSUED AT 315 AM EDT WEAK GRADIENT FLOW ACROSS EASTERN 2/3RDS OF THE CONUS PER LATEST SURFACE ANALYSIS. YESTERDAYS WEAK WAVE RESULTED WITH LITTLE IN THE RAIN ADDING IN THE BUCKET AS THIS WAVE CONTINUES TO WEAKEN AND PUSH OFFSHORE. FURTHER UPSTREAM, YET ANOTHER WAVE NOW MOVING INTO NORTH DAKOTA. THIS WAVE APPEARS TO BE PACKING A LITTLE MORE OF A PUNCH WITH H2O VAPOR REPRESENTATION INDICATING A SMALL COMMA HEAD AND SATELLITE DERIVED WINDS INDICATING JET COUPLING WITH 70-80 KNTS. THIS HAS RESULTED IN CONVECTION WITH LIGHTNING STRIKES JUST NORTH OF THE BORDER AS OF 06Z. INBETWEEN THESE SYSTEMS, HIGH PRESSURE WHICH WILL MOVE ACROSS THE STATE TODAY. INITIALIZATION WAS FAIRLY GOOD, ALTHOUGH, THE GFS APPEARS TO BE THE MODEL OF CHOICE AS WE LOOK FURTHER INTO THE FUTURE. TODAY... IN A NUTSHELL, AFOREMENTIONED SURFACE HIGH SLIDES ACROSS THE STATE TODAY WITH TRANQUIL CONDITIONS. BUT WE WILL NEED TO MONITOR STRATUS DECK WHICH IS PROGRESSING SOUTHEAST ACROSS SAGINAW BAY/THUMB WITH BORDERLINE MVFR/IFR CEILINGS. LATEST OPERATIONAL MESOSCALE MODELS ARE NOT HANDLING THIS WELL BUT TAQ RUC (EXPERIMENTAL) IS DOING BETTER WHICH BRINGS THE STRATUS DECK SOUTH ACROSS BAY, TUSCOLA, HURON, SANILAC AND PORTIONS OF ST CLAIR COUNTY BEFORE MIXING OUT AROUND 15Z. OUTSIDE OF THIS, SKIES TODAY SHOULD BE MOSTLY SUNNY. SOME HIGH/MID LEVEL MOISTURE FROM UPPER LOW OVER THE SOUTHERN PLAINS AND APPROACH OF UPSTREAM WAVE MAY BRING MORE CLOUDS THIS AFTERNOON...BUT FOR MOST PEOPLE IT SHOULD A MORE SUN THAN CLOUDS DAY. BASED ON UPSTREAM TEMPS WHICH WERE IN THE UPPER 60S AND LOWER 70S...FOLLOWING THOSE THICKNESSES WOULD TAKE MOST OF THIS SPRINGLIKE AIR SOUTH INTO THE OHIO VALLEY. WITH SURFACE HIGH MOVING ACROSS, GRADIENT WILL BE LIGHT TO MINIMIZE MIXING WHICH WOULD SUPPORT MID 50S AWAY FROM THE WATER. IT WILL BE A BIT COOLER NEAR THE LAKES AS LOCAL CHARTS SHOW LAKE BREEZES SETTING UP EARLY THIS AFTERNOON WITH LIGHT 925/950MB WINDS. TONIGHT... LAKE BREEZE ACTIVITY WILL ABATE THIS EVENING AS UPSTREAM WAVE BEGINS IT APPROACH ON THE GREAT LAKES REGION. AT THIS POINT, MODELS DO DIVERGE WITH RESPECT TO PLACEMENT OF LIFT, MOISTURE AND UPPER LEVEL SUPPORT. GIVEN UPSTREAM SPEED OF THIS SYSTEM, WE WOULD HAVE TO FAVOR THE GFS TIMING. THIS IS IN AGREEMENT WITH THE UKMET AND TAQ RUC WHICH BRINGS US TO ADD PRECIP TO THE GRIDS LATE TONIGHT. Q-VECTOR CONVERGENCE IS IMPRESSIVE AND COINCIDES WITH OMEGA PATTERN LATE TONIGHT FOR SCATTERED POPS IN THE GRIDS. WITH THE INCREASE IN THE CLOUD COVER, TEMPERATURES WILL HOLD UP A BIT INTO THE MID-UPPER 30S. THURSDAY... WE SHOULD START THE DAY WITH SCATTERED SHOWERS AS Q-VECTOR CONVERGENCE/OMEGA AND DIVERGENCE ALOFT SLIDE TO THE EAST BY LATE MORNING. SURFACE FEATURES WILL BE TOUGH TO PIN DOWN WITH WEAK LOW PASSING ACROSS THE LOWER HALF OF THE STATE LEAVING BEHIND SURFACE TROF/COLD FRONT ACROSS THE REGION. HERE IS WHERE SOME MAJOR DIFFERENCES OCCUR AS THE ETA SWINGS A DRY SLOT ACROSS THE SOUTHERN COUNTIES WHILE THE GFS IS FURTHER SOUTH INTO THE OHIO VALLEY. THIS WOULD AGREE WITH THE UKMET AND TAQ RUC TO KEEP THE CLOUDS AND THE CHANCE FOR LIGHT SHOWER ACTIVITY FOR THE REMAINDER OF THE DAY. WITH THE EXPECTED CLOUD COVER AND PRECIP, WE WILL NEED TO BRING DOWN OUR EXPECTED MAX TEMPS A BIT WITH THE HIGHER VALUES POSSIBLE FROM ARB-DTW SOUTHWARD. THURSDAY NIGHT... THIS CAN PROVE TO BE THE MOST CHALLENGING ASPECT OF THE FORECAST AND WILL LIKELY CHANGE. LATEST GUIDANCE NOW POINTS TOWARD SHORT WAVE TROF TO MOVE SOUTHEAST ACROSS THE CWA PUSHING SURFACE COLD FRONT SOUTH. MOISTURE COLUMN IS MORE MOIST THIS RUN WITH GFS OMEGA FIELDS FOCUSING ACROSS THE NORTHERN HALF OF THE CWA. WITH SOME SURFACE CONVERGENCE AND THE CHANCE FOR SOME MID LEVEL WAVE AFFECTING THE NORTHWEST FLOW REGIME, WE WILL BRING IN A CHANCE FOR A RAIN/SNOW MIX NORTH WHERE THICKNESSES AND SOUNDINGS ARE BORDERLINE...AND A BIT WARMER SOUTH FOR PRIMARILY RAIN. AGAIN, CONFIDENCE IN THIS SOLUTION IS POOR AND WILL LIKELY BE MODIFIED. FRIDAY... WE FIND OURSELVES BETWEEN SYSTEMS WITH WEAK SHORT WAVE RIDGE IN PLACE. WE WILL CONTINUE WITH THE DRY FORECAST BUT KEEP THE CLOUD FESTIVAL GOING. TEMPERATURES WILL GENERALLY RANGE BETWEEN 45 AND 50 FROM NORTH TO SOUTH. LOOKING AHEAD OFFERS TOO MANY CHALLENGES TO MENTION. HOWEVER, IN SUMMARY THE 00Z GUIDANCE TAKES GULF LOW AND TRACKS THIS SYSTEM SOUTHEAST OF THE REGION AND AFFECT THE EAST COAST. THIS IS SUPPORTED BY THE 00Z CANADIAN WHICH KEEPS THE CWA UNDER HIGHER SURFACE PRESSURES BUT TROFINESS ALOFT. THANKS TO THE SURROUNDING OFFICES AND HPC FOR THE COLLABORATION! && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BGM MJS EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 230 PM MST WED APR 07 2004 .SYNOPSIS...SHOWERS AND THUNDERSTORMS WILL CONTINUE OVERNIGHT AS A LOW PRESSURE SYSTEM SLOWLY MOVES ACROSS THE STATE. SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE THURSDAY AND FRIDAY. ANOTHER WEAK SYSTEM WILL BRING A INCREASE IN SHOWERS AND THUNDERSTORMS ON SATURDAY. DRY AND WARMER WEATHER WILL RETURN ON SUNDAY AND LINGER THROUGH MID WEEK A HIGH PRESSURE BUILDS ACROSS THE DESERT SOUTHWEST. && .DISCUSSION...COLD UPPER LOW CONTINUES TO MOVE ACROSS NW AZ. SATELLITE IMAGES SUGGEST CENTER IS TAKING A SLOWER AND MORE SOUTHERLY TRACK THAN DEPICTED ON 12Z MODEL RUNS. 17Z RUC HAS LOW CENTER OVER W YAVAPAI COUNTY AT 00Z. PLENTY OF SHOWERS AND TSTMS SEEN ON RADAR OVER WESTERN HALF OF THE CWA ATTM WITH ECHOES STARTING TO INCREASE OVER THE EASTERN SECTIONS. SPOTTERS REPORT ONLY SMALL HAIL WITH THESE STORMS THIS MORNING. EXPECT THIS ACTIVITY TO CONTINUE THRU THE EVENING WEST OF THE RIM AND THRU OUT THE NIGHT FOR THE EASTERN CWA. LOW WILL BE CENTERED NEAR RQE BY 12Z TOMORROW THEN MOVES INTO NM DURING THE AFTERNOON. WILL SEE ISOLATED TO SCT ACTIVITY TOMORROW WITH THE HIGHEST POPS OUT EAST. ATMOSPHERE REMAINS MOIST AND SLIGHTLY UNSTABLE ON FRIDAY FOR A LOW THREAT OF CONVECTION. WILL SEE MAX TEMPS WARM A LITTLE THRU FRIDAY. EXTENDED...GFS AND ECMWF SIMILAR IN BRINGING ANOTHER S/WV TROF SOUTH ACROSS THE STATE SATURDAY NIGHT AND SATURDAY. THERE WILL BE PLENTY OF MOISTURE AROUND. WILL RAISE POPS FOR THIS TIME PERIOD TO THE SCT CATEGORY. EXPECT THE AIR MASS TO DRY AND STABILIZE FROM THE WEST ON SUNDAY AS RIDGE BUILD OVER THE WEST COAST. WILL KEEP A SLIGHT CHANCE OF PRECIP OVER THE WHITE'S ON SUNDAY. WX LOOKS DRY AND WARMER THRU MID WEEK. DF && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ az