AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 952 AM EST SAT NOV 26 2005 SATELLITE IMAGERY CONTINUES TO SHOW A STREAM OF HIGH CLOUDS OVER THE AREA THANKS IN PART TO A STRONG ZONAL JET NEAR 130 KT OVER N GA AND SC. PATCHY DENSE FOG AND LOW CLOUDS ARE SLOW TO BURN OFF DUE TO SLOWER HEATING OVER SE GA. MEAN LAYER RIDGE OVER CENTRAL AND N FL WILL SHIFT EWD IN RESPONSE TO SHORTWAVE TROUGH MOVING THROUGH TX AND LA BRINGING SLY FLOW TO MAJORITY OF THE CWA. AT SFC...HIGH PRES CENTER OVER NC AND MID ATLC AREA WILL MOVE E TODAY ALLOWING THE CURRENT NE FLOW TO VEER AND INCREASE A BIT. WEAK TROUGHING IS NOTED FROM NE FL AND THEN ENE INTO THE ATLC WITH MODERATE AMOUNT OF CONVERGENCE N OF THE TROUGH OVER THE COASTAL WATERS. THIS IS ALLOWING SOME SHOWER ACTIVITY TO DEVELOP JUST EAST OF THE OFFSHORE GA WATERS. GIVEN LOW LEVEL NE TO E FLOW THESE SHOWERS AND CONVERGENCE ARE EXPECTED TO INCREASE POPS TO SLIGHT CHANCE OVER COASTAL GA ZONES LATER TODAY. CURRENT ZONES HANDLES THIS WELL AND GFS SEEMS TO HAVE A SLIGHT EDGE OVER THE NAM. TEMPS NEAR 70 OVER SE GA AND LOWER TO MID 70S IN FL SEEMS REASONABLE. OTHER THAN REMOVING FOG ...NO SIGNIFICANT CHANGES ANTICIPATED. MARINE...CURRENT OBS SHOW NE WINDS 16 KT AT 41008 AND ABOUT 4 KT AT 41012 NEAR THE SFC TROUGH. WILL NUDGE UP WINDS A BIT IN THE CWF AND PERHAPS SPLIT ZONES N TO S TO ACCOUNT FOR STRONGER WINDS OVER GA WATERS AND ALSO BASED ON LATEST RUC GUIDANCE. OTHERWISE NO CHANGES ANTICIPATED. && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. MARINE...NONE. && $$ ARS fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 900 PM CST SAT NOV 26 2005 .DISCUSSION... SHORTWAVE OVER THE WESTERN GULF STATES IS BEGINNING TO MOVE NORTHEASTWARD TOWARD THE MISSISSIPPI VALLEY THIS EVENING. STRONG LOW LEVEL JET IS BRINGING INCREASING AMOUNTS OF MOISTURE NORTHWARD... AND REGIONAL RADARS ARE BEGINNING TO SHOW INCREASING ECHOES TO OUR SOUTH. THIS SHOULD CONTINUE TO INCREASE OVERNIGHT SO HIGH POPS LOOK ON TARGET. WILL INCREASE POPS INTO THE CATEGORICAL RANGE OVER THE CENTRAL ZONES WHERE RADAR SHOWS LIGHT RAIN JUST UPSTREAM. THERE WILL STILL BE A CHANCE FOR ISOLATED THUNDERSTORMS LATER TONIGHT AS THE MOISTURE CONTINUES TO ADVECT INTO ILLINOIS AHEAD OF THE SHORTWAVE. THE LOW CLOUDS THAT BEGAN TO INCREASE AROUND SUNSET HAVE PUSHED EASTWARD...WITH THE WESTERN AREAS ONLY SEEING MID AND HIGH CLOUDS AT THIS TIME. THIS HAS ALLOWED TEMPERATURES TO FALL A LITTLE MORE THAN PREVIOUSLY EXPECTED. SURFACE DEWPOINTS ARE RISING INTO THE LOWER 40S IN THE SOUTHWEST...WITH MID 30S COMMON ELSEWHERE. WILL THEREFORE ADJUST MIN TEMPERATURES DOWNWARD A FEW DEGREES. WITH MORE CLOUDS EXPECTED TO DEVELOP LATER ON...TEMPERATURES WILL STILL BE ON THE MILD SIDE. && .PREV DISCUSSION... MANY POINTS OF INTEREST THIS FORECAST. 2 MAIN WAVES OF PRECIP ON TAP THIS FORECAST. ONE AFTER MIDNIGHT TONIGHT AND SUN MORNING... THE OTHER ON SUNDAY NIGHT AND MONDAY MORNING. OVERALL...THE MODELS ARE COMING CLOSER TOGETHER ON THE TIMING OF THE NEXT TWO PUSHES OF PRECIP. THEY ALL HAVE HAD RUN TO RUN DIFFERENCES...BUT AGREE QUITE WELL THROUGH 54 HRS. THEN THE GFS AND CANADIAN GEM GLOBAL LIFT THE LOW INTO CANADA WHILE THE NAM KEEPS A SECONDARY LOW OVER N WIS/LAKE SUPERIOR THROUGH TUESDAY NIGHT. ONCE AGAIN...LEANED TWRD GFS FOR THE DETAILS. SHORT TERM...TONIGHT THROUGH MONDAY NIGHT... A THUNDERSTORM COMPLEX HAS ERUPTED OUT AHEAD OF THE MAIN H5 TROUGH THIS AFTERNOON. IT SEEMS TO BE TIED TO A SHORTWAVE NOT CAPTURED BY THE MODELS...ALTHOUGH RUC HAS JUST INDICATED A WIGGLE IN THE H5 FLOW. THE STORM SYSTEM IS HEADED TOWARD OUR SW ZONES AND SHOULD REACH THEM BY 00Z. I HAVE INCREASED POPS TO CATEGORICAL FOR THIS EVENING FOR THAT AREA...WITH THE MAIN FOCUS FOR PRECIP EVERYWHERE TO BE PRIMARILY AFTER MIDNIGHT. KEPT THE DISTRIBUTION OF HIGHEST POPS IN THE SE HALF OF THE CWA...WITH LIKELY POPS IN THE NW HALF. THIS STILL APPEARS ON TRACK...PER ALL THE SHORT TERM MODELS. KEPT THE SUNDAY MORNING CAT POPS IN THE EAST...WITH LIKELY POPS WEST. THE SLOWING OF THE FRONTAL SYSTEM SHOULD ALLOW FOR ADDITIONAL PRECIP ON SUNDAY MORNING. A BREAK IN THE ACTION IS EXPECTED FOR SUNDAY AFTERNOON... WITH THE NEXT STRONGER WAVE OF PRECIP COMING IN TOWARD 06Z ON MONDAY. THIS COMPLEX WILL HAVE VERY STRONG SHEAR ASSOCIATED WITH IT. BULK SHEAR READINGS UP NEAR 80...WITH A 70 KT LLJ AT H85 CRANKING UP IN OUR E CWA. EVEN IF INSTABILITY WILL NOT BE ESPECIALLY HIGH (CAPE VALUES 200-400 J/KG)...THIS ENVIRONMENT WILL BE CONDUCIVE TO ROTATING STORMS...AND QUICK SPIN-UP TORNADOES. THE BEST INSTABILITY WILL BE TOWARD 00Z MONDAY...AND WILL BE SOUTH OF OUR AREA. SPC HAS US IN A SLIGHT RISK FOR DAY TWO...WITH STRAIGHT LINE WINDS THE PRIMARY THREAT. THIS IS UNDERSTANDABLE...WITH 70 KTS OF WIND WITHIN 4000 FEET OF THE SURFACE...IT WONT TAKE MUCH FOR A STORM TO MIX DOWN SEVERE WINDS (50 KTS). PRECIP WATER VALUES CLIMB OVER 1 INCH...SO MINOR FLOODING MIGHT BE POSSIBLE FOR A SHORT TIME AS THE COMPLEX MOVES QUICKLY THROUGH OUR CWA...BUT WIDESPREAD HEAVY RAINS AND FLOODING ARE NOT LIKELY. SO I REMOVED THE HEAVY RAIN SELECTION ON THE GRIDS FOR SUNDAY NIGHT/MONDAY MORNING. LINGERING PRECIP INTO MONDAY MORNING IS POSSIBLE...SO I DID NOT REDUCE THOSE POPS MUCH... IN COORD WITH SURROUNDING OFFICES...BUT HAVE A FEELING THAT AFTER ONE MAIN PUSH OF THE PRECIP WAVE OVERNIGHT...MONDAY WILL NOT FEATURE THAT MUCH PRECIP. THE DEPARTURE OF THE LOW INTO CANADA WILL HAVE AN AFFECT ON THIS...AND RIGHT NOW THE CANADIAN AND GFS ARE LEANING TOWARD THAT SOLUTION. WARM CONDITIONS WILL PREVAIL IN THE WARM SECTOR THROUGH SUNDAY NIGHT AND EARLY MONDAY MORNING...UNTIL THE COLD AIR WRAPS IN ON MONDAY. HIGHS FOR MONDAY WILL BE IN THE MORNING...WITH FALLING TEMPS FOR THE NEXT 18 HOURS AFTER THAT. ANY PRECIP ON MONDAY WILL CHANGE OVER TO SNOW IN THE AFTERNOON...BUT LITTLE ACCUMULATION IS EXPECTED. LONG TERM...TUESDAY THROUGH FRIDAY... TUESDAY WILL FEATURE CLOUDS AND VARIOUS H5 SHORTWAVES IN OUR VICINITY DUE TO THE LONG WAVE TROUGH AXIS JUST TO OUR EAST. I KEPT IN A SLIGHT CHANCE OF SNOW THAT DAY...BUT ONCE AGAIN...VERY LITTLE MOISTURE SO NO APPRECIABLE ACCUMULATION IS EXPECTED IN OUR AREA. A QUICK CLIPPER WAS INDICATED BY PREVIOUS MODELS FOR WEDNESDAY NIGHT AND THURSDAY. IT MOVED WAY NORTH OF US IN THE GFS THIS MORNING...BUT THE CANADIAN AND DGEX ARE STILL INDICATING A QUICK SHOT OF LIGHT SNOW POSSIBLE. THE UNCERTAINTY WITH THIS FEATURE LEADS ME TO KEEP ACCUMULATION AMOUNTS VERY LOW AT THIS POINT. A WARMING TREND IS EXPECTED INTO NEXT WEEKEND...AS A RIDGE DEVELOPS IN THE PLAINS AND WE RETURN TO SOUTHWEST FLOW ALOFT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 04/SHIMON il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 317 PM CST SAT NOV 26 2005 .DISCUSSION... MANY POINTS OF INTEREST THIS FORECAST. 2 MAIN WAVES OF PRECIP ON TAP THIS FORECAST. ONE AFTER MIDNIGHT TONIGHT AND SUN MORNING... THE OTHER ON SUNDAY NIGHT AND MONDAY MORNING. OVERALL...THE MODELS ARE COMING CLOSER TOGETHER ON THE TIMING OF THE NEXT TWO PUSHES OF PRECIP. THEY ALL HAVE HAD RUN TO RUN DIFFERENCES...BUT AGREE QUITE WELL THROUGH 54 HRS. THEN THE GFS AND CANADIAN GEM GLOBAL LIFT THE LOW INTO CANADA WHILE THE NAM KEEPS A SECONDARY LOW OVER N WIS/LAKE SUPERIOR THROUGH TUESDAY NIGHT. ONCE AGAIN...LEANED TWRD GFS FOR THE DETAILS. SHORT TERM...TONIGHT THROUGH MONDAY NIGHT... A THUNDERSTORM COMPLEX HAS ERUPTED OUT AHEAD OF THE MAIN H5 TROUGH THIS AFTERNOON. IT SEEMS TO BE TIED TO A SHORTWAVE NOT CAPTURED BY THE MODELS...ALTHOUGH RUC HAS JUST INDICATED A WIGGLE IN THE H5 FLOW. THE STORM SYSTEM IS HEADED TOWARD OUR SW ZONES AND SHOULD REACH THEM BY 00Z. I HAVE INCREASED POPS TO CATEGORICAL FOR THIS EVENING FOR THAT AREA...WITH THE MAIN FOCUS FOR PRECIP EVERYWHERE TO BE PRIMARILY AFTER MIDNIGHT. KEPT THE DISTRIBUTION OF HIGHEST POPS IN THE SE HALF OF THE CWA...WITH LIKELY POPS IN THE NW HALF. THIS STILL APPEARS ON TRACK...PER ALL THE SHORT TERM MODELS. KEPT THE SUNDAY MORNING CAT POPS IN THE EAST...WITH LIKELY POPS WEST. THE SLOWING OF THE FRONTAL SYSTEM SHOULD ALLOW FOR ADDITIONAL PRECIP ON SUNDAY MORNING. A BREAK IN THE ACTION IS EXPECTED FOR SUNDAY AFTERNOON... WITH THE NEXT STRONGER WAVE OF PRECIP COMING IN TOWARD 06Z ON MONDAY. THIS COMPLEX WILL HAVE VERY STRONG SHEAR ASSOCIATED WITH IT. BULK SHEAR READINGS UP NEAR 80...WITH A 70 KT LLJ AT H85 CRANKING UP IN OUR E CWA. EVEN IF INSTABILITY WILL NOT BE ESPECIALLY HIGH (CAPE VALUES 200-400 J/KG)...THIS ENVIRONMENT WILL BE CONDUCIVE TO ROTATING STORMS...AND QUICK SPIN-UP TORNADOES. THE BEST INSTABILITY WILL BE TOWARD 00Z MONDAY...AND WILL BE SOUTH OF OUR AREA. SPC HAS US IN A SLIGHT RISK FOR DAY TWO...WITH STRAIGHT LINE WINDS THE PRIMARY THREAT. THIS IS UNDERSTANDABLE...WITH 70 KTS OF WIND WITHIN 4000 FEET OF THE SURFACE...IT WONT TAKE MUCH FOR A STORM TO MIX DOWN SEVERE WINDS (50 KTS). PRECIP WATER VALUES CLIMB OVER 1 INCH...SO MINOR FLOODING MIGHT BE POSSIBLE FOR A SHORT TIME AS THE COMPLEX MOVES QUICKLY THROUGH OUR CWA...BUT WIDESPREAD HEAVY RAINS AND FLOODING ARE NOT LIKELY. SO I REMOVED THE HEAVY RAIN SELECTION ON THE GRIDS FOR SUNDAY NIGHT/MONDAY MORNING. LINGERING PRECIP INTO MONDAY MORNING IS POSSIBLE...SO I DID NOT REDUCE THOSE POPS MUCH... IN COORD WITH SURROUNDING OFFICES...BUT HAVE A FEELING THAT AFTER ONE MAIN PUSH OF THE PRECIP WAVE OVERNIGHT...MONDAY WILL NOT FEATURE THAT MUCH PRECIP. THE DEPARTURE OF THE LOW INTO CANADA WILL HAVE AN AFFECT ON THIS...AND RIGHT NOW THE CANADIAN AND GFS ARE LEANING TOWARD THAT SOLUTION. WARM CONDITIONS WILL PREVAIL IN THE WARM SECTOR THROUGH SUNDAY NIGHT AND EARLY MONDAY MORNING...UNTIL THE COLD AIR WRAPS IN ON MONDAY. HIGHS FOR MONDAY WILL BE IN THE MORNING...WITH FALLING TEMPS FOR THE NEXT 18 HOURS AFTER THAT. ANY PRECIP ON MONDAY WILL CHANGE OVER TO SNOW IN THE AFTERNOON...BUT LITTLE ACCUMULATION IS EXPECTED. LONG TERM...TUESDAY THROUGH FRIDAY... TUESDAY WILL FEATURE CLOUDS AND VARIOUS H5 SHORTWAVES IN OUR VICINITY DUE TO THE LONG WAVE TROUGH AXIS JUST TO OUR EAST. I KEPT IN A SLIGHT CHANCE OF SNOW THAT DAY...BUT ONCE AGAIN...VERY LITTLE MOISTURE SO NO APPRECIABLE ACCUMULATION IS EXPECTED IN OUR AREA. A QUICK CLIPPER WAS INDICATED BY PREVIOUS MODELS FOR WEDNESDAY NIGHT AND THURSDAY. IT MOVED WAY NORTH OF US IN THE GFS THIS MORNING...BUT THE CANADIAN AND DGEX ARE STILL INDICATING A QUICK SHOT OF LIGHT SNOW POSSIBLE. THE UNCERTAINTY WITH THIS FEATURE LEADS ME TO KEEP ACCUMULATION AMOUNTS VERY LOW AT THIS POINT. A WARMING TREND IS EXPECTED INTO NEXT WEEKEND...AS A RIDGE DEVELOPS IN THE PLAINS AND WE RETURN TO SOUTHWEST FLOW ALOFT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHIMON il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1032 PM EST SAT NOV 26 2005 .UPDATE... THE 03 SURFACE ANALYSIS SHOWS A FRONTAL BOUNDARY EXTENDING FROM JUST NORTH OF CHICAGO ACROSS EXTREME SW LOWER MI...THEN INTO NORTH CENTRAL OHIO. THIS FRONT WILL SLOWLY PUSH NORTH DURING THE NIGHT. THETA E ADVECTION NEAR 850MB IS ONGOING ACROSS SOUTHERN MICHIGAN AND IS RESULTING IN AN EXPANDING STRATUS DECK. THIS STRATUS WILL EVENTUALLY WORK INTO THE SAGINAW VALLEY AND THUMB DURING THE OVERNIGHT. WITH WARM AIR ADVECTION ABOVE THE NOCTURNAL BOUNDARY LAYER AND WITH THE EXPANDING CLOUD COVER... TEMPS SHOULD SLOWLY RISE OVERNIGHT. THE 00Z UPPER AIR PLOTS SHOWED A MOISTURE GRADIENT NEAR 700MB ACROSS THE OHIO VALLEY. THIS MOISTURE ADVECTION WILL LIFT INTO THE SOUTHERN GREAT LAKES OVERNIGHT AS AN UPPER TROUGH OVER THE SOUTHERN PLAINS LIFTS INTO THE MID MISSISSIPPI VALLEY. THIS 700MB MOISTURE ADVECTION HAS TRIGGERED SOME RADAR RETURNS ACROSS NORTH CENTRAL OHIO. THUS THINK THE CURRENT CHANCE POPS ACROSS THE SOUTH OVERNIGHT LOOK REASONABLE AS THE MOISTURE WORKS INTO THE AREA. THE CURRENT FORECAST LOOKS TO HAVE A GOOD HANDLE ON TEMPERATURE TRENDS AND PRECIP CHANCES OVERNIGHT. SO NO UPDATE WILL BE ISSUED. && .AVIATION... ISSUED AT 636 PM A MID LEVEL TROUGH AXIS OVER THE SOUTHERN PLAINS WILL LIFT NORTHEAST INTO THE GREAT LAKES REGION BY MONDAY AFTERNOON. PERIODS OF LOW LEVEL WARM AIR ADVECTION AND MOISTURE ADVECTION WILL AFFECT SOUTHEAST MICHIGAN TONIGHT AND THROUGH THE DAY SUNDAY IN ADVANCE OF THIS WAVE. LOW LEVEL MOISTURE ADVECTION IS ALREADY RESULTING IN THE EXPANSION OF A STRATUS DECK BASED AROUND 4500 FT ACROSS SOUTHERN MICHIGAN. THESE CLOUDS WILL EXPAND NORTH AND EAST AND AFFECT ALL THE TAF SITES WITHIN THE NEXT ONE TO TWO HOURS. LOOKS LIKE THE BEST LIFT WILL ARRIVE INTO SE MICHIGAN IN A SERIES OF WAVES. THE FIRST SHOULD ARRIVE DURING THE MORNING AS STRONG LOW LEVEL MOISTURE ADVECTS NORTH ACROSS THE AREA. THE COMBINATION OF RAIN AND SNOWMELT WILL RESULT IN MVFR CEILINGS AND MVFR AND IFR VISIBILITY. THE NEXT AREA OF STRONGER LIFT SHOULD ARRIVE LATE IN THE AFTERNOON AND PERSIST THROUGH THE END OF THE TAF PERIOD AS THE UPPER WAVE LIFTS ACROSS THE STATE. THE 18Z NAM AND GFS INDICATE A BRIEF PERIOD OF VFR CONDITIONS AROUND DETROIT IN THE EARLY AFTERNOON BEFORE THE NEXT WAVE ARRIVES...WITH FNT AND MBS REMAINING MVFR THROUGH THE AFTERNOON. WILL KEEP CEILINGS AND VISIBILITY MVFR LATE IN THE TAF PERIOD. PERSISTENT SURFACE MOISTURE ADVECTION OVER THE RECENT SNOWMELT MAY HOWEVER CREATE IFR OR LIFR VISIBILITIES TOWARD THE END OF THE TAF PERIOD. THIS WILL CONTINUE TO BE MONITORED. && .SHORT TERM...TONIGHT AND SUNDAY SHORTWAVE OVER EASTERN TEXAS HAS MADE THE TURN TO THE NORTHEAST...AND WILL BE MOVING THROUGH THE CENTRAL GREAT LAKES LATE TOMORROW. THIS SHORTWAVE WILL DELIVER A NICE SURGE OF GULF MOISTURE TO LOWER MICHIGAN TOMORROW...RESULTING IN OVERRUNNING RAINFALL. 12Z NAM/GFS 295-290 K ISENTROPIC ANALYSIS SHOWING VARYING LIFT THROUGHOUT THE DAY...MAKING THE TIMING OF RAINFALL A LITTLE DIFFICULT. EVEN WHEN THE LIFT/FORCING IS LACKING...WILL LIKELY SEE SOME DRIZZLE WITH 40+ DEW POINTS RIDING OVER THE SNOWCOVER HERE IN SOUTHEAST MICHIGAN. THUS...OCCASIONAL RAIN AND FOG SHOULD COVER TOMORROW JUST FINE. HAVE NOTED THE ELEVATED THUNDERSTORMS ACROSS SOUTHEAST MISSOURI EARLY THIS AFTERNOON. 12Z NAM DOES INDICATE THE SHOWALTER INDEX APPROACHING ZERO BY 12Z SUNDAY ACROSS SOUTHERN LOWER MICHIGAN. HOWEVER...WITH THE MAIN LOW LEVEL JET WEST OF THE REGION...WILL KEEP THE MENTION OF THUNDERSTORMS OUT...IN LINE WITH THE DAY 1 OUTLOOK ISSUED AT 1630Z. FOLLOWED GFS MOS GUIDANCE FOR TEMPS TOMORROW. HOWEVER...TONIGHT IS A DIFFERENT STORY. HAVE GONE 3-6 DEGREES COLDER THAN GUIDANCE. WITH LIGHT WINDS AND PARTLY CLOUDY SKIES THIS EVENING...TEMPS SHOULD DIVE QUICKLY WITH SNOW COVER AND DEW POINTS STILL HOVERING IN THE MID TEENS TO LOWER 20S. 12Z NAM INDICATING 3Z SUNDAY TEMPS IN THE LOWER 20S ACROSS THE NORTH HALF OF THE CWA WHICH SEEMS REASONABLE... ESPECIALLY WITH TEMPS STILL IN THE UPPER 20S AS OF MID AFTERNOON. 12Z RUC13 IS EVEN FORECASTING SURFACE TEMPS IN THE TEENS OVER THE THUMB REGION. THAT SHOULD NOT HAPPEN UNLESS SKIES ARE CLEAR THIS EVENING...WHICH IS NOT IN THE FORECAST DUE TO WARM ADVECTION HIGH CLOUDS STREAMING IN FROM THE WESTERN GREAT LAKES. THINKING TEMPS WILL BE JUST ABOVE FREEZING WHEN RAIN ARRIVES TOMORROW MORNING ACROSS THE NORTH HALF...THUS NO MENTION OF FREEZING RAIN. WARM RAIN DROPS (850 MB TEMPS OF 5 C BY 12Z SUNDAY ACROSS NORTHERN THIRD OF CWA PER BLEND OF NAM/GFS) WITH A SURFACE TEMP OF 32 DEGREES SHOULD NOT CAUSE FREEZING ON CONTACT. NOT TO MENTION SOIL TEMPS ARE STILL ABOVE FREEZING UNDERNEATH THE SNOW. && .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY OVERALL FORECAST CHALLENGES REMAIN THE SAME AS STRONG STORM SYSTEM WRAPS UP THE WEST...FIRST BRINGING MUCH MILDER AIR IN LOWER MICHIGAN EARLY THIS WEEK AS IT FORCES A WARM FRONT NORTH OF THE AREA SUNDAY. THEREAFTER...COLD/OCCLUDED FRONT PROGRESSES THROUGH THE AREA MONDAY WITH THE ATMOSPHERE...IN GENERAL...STEADILY COOLING THE REMAINDER OF THE WEEK (BEFORE ANOTHER SYSTEM RACING ACROSS THE NORTHERN TIER OF THE CONUS BRINGS SOME BRIEF MODIFICATION LATE IN THE FORECAST). RAIN STILL LOOKS TO BE A GOOD BET ON MONDAY/MONDAY EVENING AS COLD FRONT SLOWLY PUSHES THROUGH THE AREA. THERE IS STILL SOME QUESTION AS TO WHETHER THERE WILL BE ANY THUNDER. VERY LITTLE INSTABILITY IS PROGGED...AND FORCING/CONVERGENCE ALONG THE FRONT WILL NOT BE GREAT GIVEN FACT THAT OVERALL FLOW IS PARALLEL TO THE FRONT. THIS LEAVES THE DYNAMIC LIFT FROM THE SYSTEM...WHICH WILL BE DECENT...BUT WITH THE CORE OF THE STORM SO FAR WEST...NOT GREAT EITHER. GIVEN THE FACT THAT A LOT OF THE "INGREDIENTS" ARE MISSING/LACKING...WILL CONTINUE WITH JUST RAIN LIKELY AND NO THUNDER MENTION. DID ADJUST THE TIMING AS PROGRESSION OF THE FRONT IS SLOWER AND RAIN APPEARS TO BE A GOOD BET INTO MONDAY EVENING (AND LESS OF A LIKELIHOOD ON MONDAY MORNING AS WELL). THEREAFTER...THE TRANSITION FROM RAIN TO SNOW BECOMES THE ISSUE AS COLDER AIR FILTERS IN MONDAY NIGHT AND TUESDAY...ALTHOUGH INTENSITY BY THAT TIME WILL BE VERY LIGHT PRECIPITATION (MORE SHOWERY-TYPE). WILL ADJUST TIMING OF -RASN MIX TO TUESDAY MORNING AND ALL -SHSN BY TUESDAY AFTERNOON AFTER COLLABORATION THIS AFTERNOON. PATTERN REMAINS LARGELY UNSETTLED IN COLD UPPER TROF FOR THE REST OF THE FORECAST. WILL ADJUST THE PERIOD WEDNESDAY/WEDNESDAY NIGHT TO DENOTE A LULL IN THE SNOW SHOWERS WITH JUST A FLURRY MENTION...AND THEN BRING THE CHANCE OF MEASURABLE LIGHT SNOW BACK THURSDAY AND MORE OR LESS INTO THE WEEKEND AS NEXT SYSTEM SLIDES INTO THE LAKES REGION. VERY LITTLE CONFIDENCE IN HOW TO HANDLE DAYS 5-7. SEEMS THE BETTER CHANCE OF LIGHT SNOW WILL COME IN THE THURSDAY/FRIDAY AREA GIVEN TIMING OF THE PACIFIC SYSTEM THAT RIDES INTO THE AREA...AND THEN A BRIEF QUIET PERIOD HEADING INTO NEXT WEEKEND. THE PROBLEM IS THAT THE ERRORS IN THIS PATTERN COULD EASILY CHANGE THE TIMING OF THE SYSTEM (AND SUBSEQUENT ONES) BY A SOLID DAY. WILL TRY NOT TO GET TOO CUTE WITH THE FORECAST AT THIS TIME. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...SMALL CRAFT ADVISORY....LATE SUNDAY AFTERNOON THROUGH LATE TUESDAY NIGHT. NEARSHORE WATERS FROM HARBOR BEACH TO PORT HURON AND FOR SAGINAW BAY...SMALL CRAFT ADVISORY...SUNDAY EVENING THROUGH LATE TUESDAY NIGHT. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....DG AVIATION/UPDATE.....CONSIDINE YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1010 PM EST SAT NOV 26 2005 .UPDATE... MAIN FCST ISSUE IS POTENTIAL OF FZDZ LATER TONIGHT. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF LIFTING NE OUT OF THE GREAT LAKES. UPSTREAM...RIDGE WAS APPROACHING THE WRN GREAT LAKES DOWNSTREAM OF DEEPENING TROF OVER THE ROCKIES. A LEAD SHORTWAVE TROF EXTENDED FROM THE SRN PLAINS TO THE WRN GULF OF MEXICO. DEEP SRLY FLOW WAS ALREADY SETTING UP ACROSS THE PLAINS AHEAD OF WRN TROF PER 00Z RAOBS. MOISTURE WAS ALSO SURGING N...PARTICULARLY AHEAD OF LEAD SHORTWAVE TROF. 850MB DWPTS ARE UP TO 9C AS FAR N AS NE KS AT KTOP WITH PRECIPITABLE WATER UP TO NEARLY 0.90 INCHES THERE AND NEARLY AN INCH INTO SRN MO. THIS MOISTURE WILL SET THE STAGE FOR WIDESPREAD RAINFALL SUN AFTN THRU MON AS WRN TROF DEEPENS AND HEADS NE TOWARD THE GREAT LAKES. CLOSER TO HOME...DEVELOPING SERLY LOW-LEVEL FLOW HAS RESULTED IN EXPANDING STRATOCU/STRATUS DECK OFF LAKE MICHIGAN THIS EVENING AS OVERWATER INSTABILITY IS STILL SUFFICIENT FOR CLOUDS...ESPECIALLY AS AIRMASS IS LIFTED UP THE TERRAIN IN CENTRAL UPPER MI. ABOVE THIS RELATIVELY SHALLOW MOIST LAYER...00Z KGRB/KMPX SOUNDINGS SHOW DEEP DRY MIDLEVELS...SUGGESTING POTENTIAL OF DZ AS MOISTURE DOES NOT EXTEND TO -8C OR COLDER ISOTHERM. BOTH OF THESE SOUNDINGS LOOK REPRESENTATIVE OF MIDLEVEL AIRMASS THAT WILL BE OVER UPPER MI OVERNIGHT. THERE REALLY IS NOT ANYTHING APPARENT THIS EVENING THAT SUGGESTS SIGNIFICANT CHANGES ARE NEEDED TO GOING FCST. SOME MINOR ADJUSTMENTS WILL BE NEEDED THOUGH. LOW-LEVEL FLOW OVERNIGHT WILL BE ORIGINATING FROM LOWER MI WHERE SFC DWPTS ARE STILL QUITE LOW...AT LEAST NOT ANY HIGHER THAN WHAT IS ALREADY BEING OBSERVED OVER UPPER MI. SO... EXPANSION OF LOW CLOUDS AND POSSIBILITY OF FZDZ OVERNIGHT WILL REALLY BE A FUNCTION OF AIRMASS PICKING UP MOISTURE OVER LAKE MICHIGAN AND THEN UPSLOPING OVER THE FCST AREA. HOWEVER...WITHOUT SIGNIFICANT LOW-LEVEL MOISTENING OUTSIDE OF LAKE CONTRIBUTION (WHICH WILL GRADUALLY DIMINISH AS WAA CONTINUES)...BELIEVE THREAT OF FZDZ MAY BE DELAYED A BIT...PROBABLY TO COINCIDE MORE CLOSELY WITH STRONGER LOW-LEVEL MOIST ISENTROPIC ASCENT WHICH ARRIVES VERY LATE TONIGHT. WILL HOLD ONTO GOING START TIMES FOR ADVY...BUT WILL REMOVE MENTION OF PCPN PRIOR TO ADVY TIME. TEMPS SHOULD REMAIN STEADY OR SLOWLY RISE FOR THE REST OF THE NIGHT. && .PREV DISCUSSION... ISSUED AT 410 PM EST MAIN FCST CONCERNS ARE POTENTIAL FOR ICING WITH -FZDZ LATE TONIGHT AND SUN MORNING. WV IMAGERY...12Z RAOBS AND RUC ANALYSIS INDICATED LINGERING WNW MID/UPPER LEVEL FLOW ACRS THE WRN LAKES BTWN THE HUDSON BAY TROF AND A RDG INTO THE NRN PLAINS. MAIN FEATURES OF INTEREST WAS THE STRONG 300/250 MB JET AND ASSOCIATED SHRTWV MOVING THROUGH THE SW CONUS. AT THE SFC...A RDG EXTENDED FROM QUEBEC TO NRN MN WHILE A WARM FRONT EXTENDED FROM NRN NEB THROUGH CNTRL IA AND NRN IL AHEAD OF DEVELOPING LOW PRES OVER THE PLAINS. DEWPOINTS HAD QUICKLY CLIMBED INTO THE 40S FROM KS INTO SE NEB AND 50S OVER OK WITH STRONG SRLY FLOW FROM THE GULF. BANDS OF MID LVL WAA CLOUDS HAD ALREADY DEVELOPED ACRS MN/WI AND UPR MI. HOWEVER...WEAK S TO SE FLOW FROM LK MI INTO SE UPR MI HAS BROUGHT SOME LOWER CLOUDS AND SOME FLURRIES VCNTY KERY. TONIGHT INTO SUN MORNING...WAA WITH CLIMBING 850 MB TEMPS...LOSS OF MOISTURE IN THE -8C LYR OR ABV...AND INCREASING SHEAR WILL BE UNFAVORABLE FOR MUCH IN THE WAY OF FLURRIES OVER THE SE THIS EVENING. HOWEVER...CANNOT RULE OUT SOME PATCHY -FZDZ DOWNWIND FROM LAKE MICHIGAN AND FARTHER NW WITH UPSLOPE INTO SLIGHTLY HIGHER TERRAIN. LATER TONIGHT...THE NAM/GFS HAVE BEEN REASONABLY CONSISTENT IN BRINGING SIGNIFICANT INCREASE IN SFC-850 RH TOWARD THE AREA AS WAA STRENGTHENS. WHILE THE MDLS MIGHT BE GENEROUS WITH THE QPF IN SHALLOW MOISTURE REGIME...IT STILL SEEMS THAT THEY HAVE THE RIGHT IDEA WITH DECENT POTENTIAL FOR MEASURABLE PCPN WITH BAND OF 290K NET ISENTROPIC LIFT MOVING THROUGH. ADDITIONAL LOW LVL OROGRAPHIC LIFT WOULD ALSO HELP TO SQUEEZE OUT SOME PCPN. SINCE TEMPS AOA 925 MB CLIMB ABOVE FREEZING AND PRFL IS DRY AOA -10C...AREAS OF -FZDZ SHOULD DEVELOP. EVEN THROUGH DZ SIZE DROPLETS ARE EXPECTED...OF CHOICES AVBL...FZRA ADVY HEADLINE BEST COVERS IMPENDING HAZARDS FROM GLAZE ON UNTREATED ROADS/SIDEWALKS. 2M TEMPS ARE EXPECTED TO CLIMB ABV FREEZING AROUND 14Z-16Z BUT THERE SHOULD BE A LAG IN WARMING COLD PAVEMENT AFTER RECENT COLD SPELL. THE KEWEENAW AND FAR EAST CWA WERE NOT INCLUDED AS BEST MOISTURE REACHES THOSE AREAS WHEN SFC/2M TEMPS CLIMB ABV FREEZING LATER IN THE MORNING. SUN AFTERNOON INTO SUN NIGHT...GIVEN THE INTENSITY OF THE SHRTWV MOVING THROUGH SW AND TYPICAL MDL PERFORMANCE..THE SLOWER STRONGER/GFS WAS PREFERRED COMPARED TO THE NAM. GFS INITIAL VORT MAY HAVE SOME CONVECTIVE FEEDBACK BUT NAM/GFS AND THE CMC HINT THAT LEAD SHRTWV MOVING NORTH INTO THE AREA IN THE AFTERNOON WILL BRING BETTER CHANCE FOR MORE RAIN SHOWERS IN THE AFTERNOON OR EVENING. WITH VERY STRONG H8 WAA CONTINUING AND H8 DEWPINTS TO NEAR 7C GIVING SHOWALTER INDEX CLOSE TO 0C...CANNOT RULE OUT SOME ISOLD TSRA...ESPECIALLY OVER THE SOUTH. WITH RELATIVELY WARM MOIST AIR OVER MELTING SNOWPACK...AREAS OF DENSE FOG STILL LOOK LIKELY...ESPECIALLY IN PERIODS WHEN RAIN TAPERS OFF. MON...DRY SLOT MOVES SHOULD MOVE INTO THE W HLF OF UPR MI WITH WARM CONVEYOR MOISTURE AND HEAVIER RAIN SHIFTING INTO THE ERN CWA. WILL KEEP GOING CATEGORICAL POPS GOING WITH LINGERING TIMING/LOCATION UNCERTAINTY OF THESE FEATURES. MON NIGHT...MDLS HAVE TRENDED SLOWER WITH THE PROGRESSION OF THE MID LVL AND SFC LOW SO CHANGEOVER TO SNOW WAS ADJUSTED ACCORDINGLY. TUE...LEFT OVER WRAP-AROUND -SN WILL TAPER OFF BUT LAKE ENHANCEMENT WITH H8 TEMPS TO NEAR -10C MAY KEEP MORE SUBSTANTIAL -SHSN GOING FOR LOCATIONS FAVORED BY WINDS VEERING TO NW. WED-SAT...GENERALLY FOLLOWED A BLEND OF THE 00Z/26 ECMWF AND THE 06Z/26 GFS WITH FAVORABLE NW LES REGIME LINGERING INTO FRI WITH SFC RDG SHIFTING INTO THE AREA BY SAT HELPING TO SHUT OFF PCPN. && .MQT...WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR MIZ009>012. FREEZING RAIN ADVISORY FROM 6 AM TO 12 PM EST SUNDAY FOR MIZ002-004>006-013-014-084-085. && $$ ROLFSON (UPDATE) JLB (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 636 PM EST SAT NOV 26 2005 .AVIATION... A MID LEVEL TROUGH AXIS OVER THE SOUTHERN PLAINS WILL LIFT NORTHEAST INTO THE GREAT LAKES REGION BY MONDAY AFTERNOON. PERIODS OF LOW LEVEL WARM AIR ADVECTION AND MOISTURE ADVECTION WILL AFFECT SOUTHEAST MICHIGAN TONIGHT AND THROUGH THE DAY SUNDAY IN ADVANCE OF THIS WAVE. LOW LEVEL MOISTURE ADVECTION IS ALREADY RESULTING IN THE EXPANSION OF A STRATUS DECK BASED AROUND 4500 FT ACROSS SOUTHERN MICHIGAN. THESE CLOUDS WILL EXPAND NORTH AND EAST AND AFFECT ALL THE TAF SITES WITHIN THE NEXT ONE TO TWO HOURS. LOOKS LIKE THE BEST LIFT WILL ARRIVE INTO SE MICHIGAN IN A SERIES OF WAVES. THE FIRST SHOULD ARRIVE DURING THE MORNING AS STRONG LOW LEVEL MOISTURE ADVECTS NORTH ACROSS THE AREA. THE COMBINATION OF RAIN AND SNOWMELT WILL RESULT IN MVFR CEILINGS AND MVFR AND IFR VISIBILITY. THE NEXT AREA OF STRONGER LIFT SHOULD ARRIVE LATE IN THE AFTERNOON AND PERSIST THROUGH THE END OF THE TAF PERIOD AS THE UPPER WAVE LIFTS ACROSS THE STATE. THE 18Z NAM AND GFS INDICATE A BRIEF PERIOD OF VFR CONDITIONS AROUND DETROIT IN THE EARLY AFTERNOON BEFORE THE NEXT WAVE ARRIVES...WITH FNT AND MBS REMAINING MVFR THROUGH THE AFTERNOON. WILL KEEP CEILINGS AND VISIBILITY MVFR LATE IN THE TAF PERIOD. PERSISTENT SURFACE MOISTURE ADVECTION OVER THE RECENT SNOWMELT MAY HOWEVER CREATE IFR OR LIFR VISIBILITIES TOWARD THE END OF THE TAF PERIOD. THIS WILL CONTINUE TO BE MONITORED. && .SHORT TERM...TONIGHT AND SUNDAY SHORTWAVE OVER EASTERN TEXAS HAS MADE THE TURN TO THE NORTHEAST...AND WILL BE MOVING THROUGH THE CENTRAL GREAT LAKES LATE TOMORROW. THIS SHORTWAVE WILL DELIVER A NICE SURGE OF GULF MOISTURE TO LOWER MICHIGAN TOMORROW...RESULTING IN OVERRUNNING RAINFALL. 12Z NAM/GFS 295-290 K ISENTROPIC ANALYSIS SHOWING VARYING LIFT THROUGHOUT THE DAY...MAKING THE TIMING OF RAINFALL A LITTLE DIFFICULT. EVEN WHEN THE LIFT/FORCING IS LACKING...WILL LIKELY SEE SOME DRIZZLE WITH 40+ DEW POINTS RIDING OVER THE SNOWCOVER HERE IN SOUTHEAST MICHIGAN. THUS...OCCASIONAL RAIN AND FOG SHOULD COVER TOMORROW JUST FINE. HAVE NOTED THE ELEVATED THUNDERSTORMS ACROSS SOUTHEAST MISSOURI EARLY THIS AFTERNOON. 12Z NAM DOES INDICATE THE SHOWALTER INDEX APPROACHING ZERO BY 12Z SUNDAY ACROSS SOUTHERN LOWER MICHIGAN. HOWEVER...WITH THE MAIN LOW LEVEL JET WEST OF THE REGION...WILL KEEP THE MENTION OF THUNDERSTORMS OUT...IN LINE WITH THE DAY 1 OUTLOOK ISSUED AT 1630Z. FOLLOWED GFS MOS GUIDANCE FOR TEMPS TOMORROW. HOWEVER...TONIGHT IS A DIFFERENT STORY. HAVE GONE 3-6 DEGREES COLDER THAN GUIDANCE. WITH LIGHT WINDS AND PARTLY CLOUDY SKIES THIS EVENING...TEMPS SHOULD DIVE QUICKLY WITH SNOW COVER AND DEW POINTS STILL HOVERING IN THE MID TEENS TO LOWER 20S. 12Z NAM INDICATING 3Z SUNDAY TEMPS IN THE LOWER 20S ACROSS THE NORTH HALF OF THE CWA WHICH SEEMS REASONABLE... ESPECIALLY WITH TEMPS STILL IN THE UPPER 20S AS OF MID AFTERNOON. 12Z RUC13 IS EVEN FORECASTING SURFACE TEMPS IN THE TEENS OVER THE THUMB REGION. THAT SHOULD NOT HAPPEN UNLESS SKIES ARE CLEAR THIS EVENING...WHICH IS NOT IN THE FORECAST DUE TO WARM ADVECTION HIGH CLOUDS STREAMING IN FROM THE WESTERN GREAT LAKES. THINKING TEMPS WILL BE JUST ABOVE FREEZING WHEN RAIN ARRIVES TOMORROW MORNING ACROSS THE NORTH HALF...THUS NO MENTION OF FREEZING RAIN. WARM RAIN DROPS (850 MB TEMPS OF 5 C BY 12Z SUNDAY ACROSS NORTHERN THIRD OF CWA PER BLEND OF NAM/GFS) WITH A SURFACE TEMP OF 32 DEGREES SHOULD NOT CAUSE FREEZING ON CONTACT. NOT TO MENTION SOIL TEMPS ARE STILL ABOVE FREEZING UNDERNEATH THE SNOW. && .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY OVERALL FORECAST CHALLENGES REMAIN THE SAME AS STRONG STORM SYSTEM WRAPS UP THE WEST...FIRST BRINGING MUCH MILDER AIR IN LOWER MICHIGAN EARLY THIS WEEK AS IT FORCES A WARM FRONT NORTH OF THE AREA SUNDAY. THEREAFTER...COLD/OCCLUDED FRONT PROGRESSES THROUGH THE AREA MONDAY WITH THE ATMOSPHERE...IN GENERAL...STEADILY COOLING THE REMAINDER OF THE WEEK (BEFORE ANOTHER SYSTEM RACING ACROSS THE NORTHERN TIER OF THE CONUS BRINGS SOME BRIEF MODIFICATION LATE IN THE FORECAST). RAIN STILL LOOKS TO BE A GOOD BET ON MONDAY/MONDAY EVENING AS COLD FRONT SLOWLY PUSHES THROUGH THE AREA. THERE IS STILL SOME QUESTION AS TO WHETHER THERE WILL BE ANY THUNDER. VERY LITTLE INSTABILITY IS PROGGED...AND FORCING/CONVERGENCE ALONG THE FRONT WILL NOT BE GREAT GIVEN FACT THAT OVERALL FLOW IS PARALLEL TO THE FRONT. THIS LEAVES THE DYNAMIC LIFT FROM THE SYSTEM...WHICH WILL BE DECENT...BUT WITH THE CORE OF THE STORM SO FAR WEST...NOT GREAT EITHER. GIVEN THE FACT THAT A LOT OF THE "INGREDIENTS" ARE MISSING/LACKING...WILL CONTINUE WITH JUST RAIN LIKELY AND NO THUNDER MENTION. DID ADJUST THE TIMING AS PROGRESSION OF THE FRONT IS SLOWER AND RAIN APPEARS TO BE A GOOD BET INTO MONDAY EVENING (AND LESS OF A LIKELIHOOD ON MONDAY MORNING AS WELL). THEREAFTER...THE TRANSITION FROM RAIN TO SNOW BECOMES THE ISSUE AS COLDER AIR FILTERS IN MONDAY NIGHT AND TUESDAY...ALTHOUGH INTENSITY BY THAT TIME WILL BE VERY LIGHT PRECIPITATION (MORE SHOWERY-TYPE). WILL ADJUST TIMING OF -RASN MIX TO TUESDAY MORNING AND ALL -SHSN BY TUESDAY AFTERNOON AFTER COLLABORATION THIS AFTERNOON. PATTERN REMAINS LARGELY UNSETTLED IN COLD UPPER TROF FOR THE REST OF THE FORECAST. WILL ADJUST THE PERIOD WEDNESDAY/WEDNESDAY NIGHT TO DENOTE A LULL IN THE SNOW SHOWERS WITH JUST A FLURRY MENTION...AND THEN BRING THE CHANCE OF MEASURABLE LIGHT SNOW BACK THURSDAY AND MORE OR LESS INTO THE WEEKEND AS NEXT SYSTEM SLIDES INTO THE LAKES REGION. VERY LITTLE CONFIDENCE IN HOW TO HANDLE DAYS 5-7. SEEMS THE BETTER CHANCE OF LIGHT SNOW WILL COME IN THE THURSDAY/FRIDAY AREA GIVEN TIMING OF THE PACIFIC SYSTEM THAT RIDES INTO THE AREA...AND THEN A BRIEF QUIET PERIOD HEADING INTO NEXT WEEKEND. THE PROBLEM IS THAT THE ERRORS IN THIS PATTERN COULD EASILY CHANGE THE TIMING OF THE SYSTEM (AND SUBSEQUENT ONES) BY A SOLID DAY. WILL TRY NOT TO GET TOO CUTE WITH THE FORECAST AT THIS TIME. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....DG AVIATION.....CONSIDINE YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EST SAT NOV 26 2005 .DISCUSSION... MAIN FCST CONCERNS ARE POTENTIAL FOR ICING WITH -FZDZ LATE TONIGHT AND SUN MORNING. WV IMAGERY...12Z RAOBS AND RUC ANALYSIS INDICATED LINGERING WNW MID/UPPER LEVEL FLOW ACRS THE WRN LAKES BTWN THE HUDSON BAY TROF AND A RDG INTO THE NRN PLAINS. MAIN FEATURES OF INTEREST WAS THE STRONG 300/250 MB JET AND ASSOCIATED SHRTWV MOVING THROUGH THE SW CONUS. AT THE SFC...A RDG EXTENDED FROM QUEBEC TO NRN MN WHILE A WARM FRONT EXTENDED FROM NRN NEB THROUGH CNTRL IA AND NRN IL AHEAD OF DEVELOPING LOW PRES OVER THE PLAINS. DEWPOINTS HAD QUICKLY CLIMBED INTO THE 40S FROM KS INTO SE NEB AND 50S OVER OK WITH STRONG SRLY FLOW FROM THE GULF. BANDS OF MID LVL WAA CLOUDS HAD ALREADY DEVELOPED ACRS MN/WI AND UPR MI. HOWEVER...WEAK S TO SE FLOW FROM LK MI INTO SE UPR MI HAS BROUGHT SOME LOWER CLOUDS AND SOME FLURRIES VCNTY KERY. TONIGHT INTO SUN MORNING...WAA WITH CLIMBING 850 MB TEMPS...LOSS OF MOISTURE IN THE -8C LYR OR ABV...AND INCREASING SHEAR WILL BE UNFAVORABLE FOR MUCH IN THE WAY OF FLURRIES OVER THE SE THIS EVENING. HOWEVER...CANNOT RULE OUT SOME PATCHY -FZDZ DOWNWIND FROM LAKE MICHIGAN AND FARTHER NW WITH UPSLOPE INTO SLIGHTLY HIGHER TERRAIN. LATER TONIGHT...THE NAM/GFS HAVE BEEN REASONABLY CONSISTENT IN BRINGING SIGNIFICANT INCREASE IN SFC-850 RH TOWARD THE AREA AS WAA STRENGTHENS. WHILE THE MDLS MIGHT BE GENEROUS WITH THE QPF IN SHALLOW MOISTURE REGIME...IT STILL SEEMS THAT THEY HAVE THE RIGHT IDEA WITH DECENT POTENTIAL FOR MEASURABLE PCPN WITH BAND OF 290K NET ISENTROPIC LIFT MOVING THROUGH. ADDITIONAL LOW LVL OROGRAPHIC LIFT WOULD ALSO HELP TO SQUEEZE OUT SOME PCPN. SINCE TEMPS AOA 925 MB CLIMB ABOVE FREEZING AND PRFL IS DRY AOA -10C...AREAS OF -FZDZ SHOULD DEVELOP. EVEN THROUGH DZ SIZE DROPLETS ARE EXPECTED...OF CHOICES AVBL...FZRA ADVY HEADLINE BEST COVERS IMPENDING HAZARDS FROM GLAZE ON UNTREATED ROADS/SIDEWALKS. 2M TEMPS ARE EXPECTED TO CLIMB ABV FREEZING AROUND 14Z-16Z BUT THERE SHOULD BE A LAG IN WARMING COLD PAVEMENT AFTER RECENT COLD SPELL. THE KEWEENAW AND FAR EAST CWA WERE NOT INCLUDED AS BEST MOISTURE REACHES THOSE AREAS WHEN SFC/2M TEMPS CLIMB ABV FREEZING LATER IN THE MORNING. SUN AFTERNOON INTO SUN NIGHT...GIVEN THE INTENSITY OF THE SHRTWV MOVING THROUGH SW AND TYPICAL MDL PERFORMANCE..THE SLOWER STRONGER/GFS WAS PREFERRED COMPARED TO THE NAM. GFS INITIAL VORT MAY HAVE SOME CONVECTIVE FEEDBACK BUT NAM/GFS AND THE CMC HINT THAT LEAD SHRTWV MOVING NORTH INTO THE AREA IN THE AFTERNOON WILL BRING BETTER CHANCE FOR MORE RAIN SHOWERS IN THE AFTERNOON OR EVENING. WITH VERY STRONG H8 WAA CONTINUING AND H8 DEWPINTS TO NEAR 7C GIVING SHOWALTER INDEX CLOSE TO 0C...CANNOT RULE OUT SOME ISOLD TSRA...ESPECIALLY OVER THE SOUTH. WITH RELATIVELY WARM MOIST AIR OVER MELTING SNOWPACK...AREAS OF DENSE FOG STILL LOOK LIKELY...ESPECIALLY IN PERIODS WHEN RAIN TAPERS OFF. MON...DRY SLOT MOVES SHOULD MOVE INTO THE W HLF OF UPR MI WITH WARM CONVEYOR MOISTURE AND HEAVIER RAIN SHIFTING INTO THE ERN CWA. WILL KEEP GOING CATEGORICAL POPS GOING WITH LINGERING TIMING/LOCATION UNCERTAINTY OF THESE FEATURES. MON NIGHT...MDLS HAVE TRENDED SLOWER WITH THE PROGRESSION OF THE MID LVL AND SFC LOW SO CHANGEOVER TO SNOW WAS ADJUSTED ACCORDINGLY. TUE...LEFT OVER WRAP-AROUND -SN WILL TAPER OFF BUT LAKE ENHANCEMENT WITH H8 TEMPS TO NEAR -10C MAY KEEP MORE SUBSTANTIAL -SHSN GOING FOR LOCATIONS FAVORED BY WINDS VEERING TO NW. WED-SAT...GENERALLY FOLLOWED A BLEND OF THE 00Z/26 ECMWF AND THE 06Z/26 GFS WITH FAVORABLE NW LES REGIME LINGERING INTO FRI WITH SFC RDG SHIFTING INTO THE AREA BY SAT HELPING TO SHUT OFF PCPN. && .MQT... FREEZING RAIN ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR MIZ009-MIZ010-MIZ011-MIZ012. FREEZING RAIN ADVISORY FROM 6 AM TO 12 PM EST SUNDAY FOR MIZ002-MIZ004-MIZ005-MIZ006-MIZ013-MIZ014-MIZ084-MIZ085. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 239 PM EST SAT NOV 26 2005 .SHORT TERM...TONIGHT AND SUNDAY SHORTWAVE OVER EASTERN TEXAS HAS MADE THE TURN TO THE NORTHEAST...AND WILL BE MOVING THROUGH THE CENTRAL GREAT LAKES LATE TOMORROW. THIS SHORTWAVE WILL DELIVER A NICE SURGE OF GULF MOISTURE TO LOWER MICHIGAN TOMORROW...RESULTING IN OVERRUNNING RAINFALL. 12Z NAM/GFS 295-290 K ISENTROPIC ANALYSIS SHOWING VARYING LIFT THROUGHOUT THE DAY...MAKING THE TIMING OF RAINFALL A LITTLE DIFFICULT. EVEN WHEN THE LIFT/FORCING IS LACKING...WILL LIKELY SEE SOME DRIZZLE WITH 40+ DEW POINTS RIDING OVER THE SNOWCOVER HERE IN SOUTHEAST MICHIGAN. THUS...OCCASIONAL RAIN AND FOG SHOULD COVER TOMORROW JUST FINE. HAVE NOTED THE ELEVATED THUNDERSTORMS ACROSS SOUTHEAST MISSOURI EARLY THIS AFTERNOON. 12Z NAM DOES INDICATE THE SHOWALTER INDEX APPROACHING ZERO BY 12Z SUNDAY ACROSS SOUTHERN LOWER MICHIGAN. HOWEVER...WITH THE MAIN LOW LEVEL JET WEST OF THE REGION...WILL KEEP THE MENTION OF THUNDERSTORMS OUT...IN LINE WITH THE DAY 1 OUTLOOK ISSUED AT 1630Z. FOLLOWED GFS MOS GUIDANCE FOR TEMPS TOMORROW. HOWEVER...TONIGHT IS A DIFFERENT STORY. HAVE GONE 3-6 DEGREES COLDER THAN GUIDANCE. WITH LIGHT WINDS AND PARTLY CLOUDY SKIES THIS EVENING...TEMPS SHOULD DIVE QUICKLY WITH SNOW COVER AND DEW POINTS STILL HOVERING IN THE MID TEENS TO LOWER 20S. 12Z NAM INDICATING 3Z SUNDAY TEMPS IN THE LOWER 20S ACROSS THE NORTH HALF OF THE CWA WHICH SEEMS REASONABLE... ESPECIALLY WITH TEMPS STILL IN THE UPPER 20S AS OF MID AFTERNOON. 12Z RUC13 IS EVEN FORECASTING SURFACE TEMPS IN THE TEENS OVER THE THUMB REGION. THAT SHOULD NOT HAPPEN UNLESS SKIES ARE CLEAR THIS EVENING...WHICH IS NOT IN THE FORECAST DUE TO WARM ADVECTION HIGH CLOUDS STREAMING IN FROM THE WESTERN GREAT LAKES. THINKING TEMPS WILL BE JUST ABOVE FREEZING WHEN RAIN ARRIVES TOMORROW MORNING ACROSS THE NORTH HALF...THUS NO MENTION OF FREEZING RAIN. WARM RAIN DROPS (850 MB TEMPS OF 5 C BY 12Z SUNDAY ACROSS NORTHERN THIRD OF CWA PER BLEND OF NAM/GFS) WITH A SURFACE TEMP OF 32 DEGREES SHOULD NOT CAUSE FREEZING ON CONTACT. NOT TO MENTION SOIL TEMPS ARE STILL ABOVE FREEZING UNDERNEATH THE SNOW. && .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY OVERALL FORECAST CHALLENGES REMAIN THE SAME AS STRONG STORM SYSTEM WRAPS UP THE WEST...FIRST BRINGING MUCH MILDER AIR IN LOWER MICHIGAN EARLY THIS WEEK AS IT FORCES A WARM FRONT NORTH OF THE AREA SUNDAY. THEREAFTER...COLD/OCCLUDED FRONT PROGRESSES THROUGH THE AREA MONDAY WITH THE ATMOSPHERE...IN GENERAL...STEADILY COOLING THE REMAINDER OF THE WEEK (BEFORE ANOTHER SYSTEM RACING ACROSS THE NORTHERN TIER OF THE CONUS BRINGS SOME BRIEF MODIFICATION LATE IN THE FORECAST). RAIN STILL LOOKS TO BE A GOOD BET ON MONDAY/MONDAY EVENING AS COLD FRONT SLOWLY PUSHES THROUGH THE AREA. THERE IS STILL SOME QUESTION AS TO WHETHER THERE WILL BE ANY THUNDER. VERY LITTLE INSTABILITY IS PROGGED...AND FORCING/CONVERGENCE ALONG THE FRONT WILL NOT BE GREAT GIVEN FACT THAT OVERALL FLOW IS PARALLEL TO THE FRONT. THIS LEAVES THE DYNAMIC LIFT FROM THE SYSTEM...WHICH WILL BE DECENT...BUT WITH THE CORE OF THE STORM SO FAR WEST...NOT GREAT EITHER. GIVEN THE FACT THAT A LOT OF THE "INGREDIENTS" ARE MISSING/LACKING...WILL CONTINUE WITH JUST RAIN LIKELY AND NO THUNDER MENTION. DID ADJUST THE TIMING AS PROGRESSION OF THE FRONT IS SLOWER AND RAIN APPEARS TO BE A GOOD BET INTO MONDAY EVENING (AND LESS OF A LIKELIHOOD ON MONDAY MORNING AS WELL). THEREAFTER...THE TRANSITION FROM RAIN TO SNOW BECOMES THE ISSUE AS COLDER AIR FILTERS IN MONDAY NIGHT AND TUESDAY...ALTHOUGH INTENSITY BY THAT TIME WILL BE VERY LIGHT PRECIPITATION (MORE SHOWERY-TYPE). WILL ADJUST TIMING OF -RASN MIX TO TUESDAY MORNING AND ALL -SHSN BY TUESDAY AFTERNOON AFTER COLLABORATION THIS AFTERNOON. PATTERN REMAINS LARGELY UNSETTLED IN COLD UPPER TROF FOR THE REST OF THE FORECAST. WILL ADJUST THE PERIOD WEDNESDAY/WEDNESDAY NIGHT TO DENOTE A LULL IN THE SNOW SHOWERS WITH JUST A FLURRY MENTION...AND THEN BRING THE CHANCE OF MEASURABLE LIGHT SNOW BACK THURSDAY AND MORE OR LESS INTO THE WEEKEND AS NEXT SYSTEM SLIDES INTO THE LAKES REGION. VERY LITTLE CONFIDENCE IN HOW TO HANDLE DAYS 5-7. SEEMS THE BETTER CHANCE OF LIGHT SNOW WILL COME IN THE THURSDAY/FRIDAY AREA GIVEN TIMING OF THE PACIFIC SYSTEM THAT RIDES INTO THE AREA...AND THEN A BRIEF QUIET PERIOD HEADING INTO NEXT WEEKEND. THE PROBLEM IS THAT THE ERRORS IN THIS PATTERN COULD EASILY CHANGE THE TIMING OF THE SYSTEM (AND SUBSEQUENT ONES) BY A SOLID DAY. WILL TRY NOT TO GET TOO CUTE WITH THE FORECAST AT THIS TIME. && .PREV DISCUSSION... (ISSUED 1200 PM EST SAT NOV 26 2005) AVIATION... THE MAIN FORECAST CHALLENGE IS DETERMINE WHEN MVFR AND EVENTUALLY IFR VSBY'S AND CEILINGS ARRIVE. NO CONCERNS THIS AFTERNOON INTO THIS EVENING AS WE WILL BE CLEAR-SCT (BELOW 20000 FEET) ONCE MID DECK (6000 FEET) OVER FNT-MBS LIFTS NORTH. SUNSHINE COUPLED WITH MAXES CLIMBING ABOVE FREEZING WILL LEAD TO SNOWMELT...WHICH WILL ADD SOME LOW LEVEL MOISTURE TO THE BOUNDARY LAYER. WITH PARTLY CLOUDY TO MOSTLY CLEAR SKIES THIS EVENING...A QUICK DROP IN TEMPERATURES WILL ALLOW THE TEMP/DEW POINT SPREAD TO DROP TO 3 OR LESS. THAT WILL PROBABLY NOT BE GOOD ENOUGH...WILL HAVE TO RELY MORE ON MOISTURE ADVECTION FOG (+32 DEGREE DEW POINTS OVERRUNNING SNOW PACK)...WHICH DOES NOT LOOK TO OCCUR UNTIL TOMORROW MORNING...SPREADING FROM SOUTH TO NORTH. BOTH GFS/NAM INDICATING VERY LOW SURFACE CONDENSATION PRESSURE DEFICITS. WILL BE CARRYING 2SM PREVAILING VSBY'S TOMORROW WITH CEILINGS AT 1500 FEET. WOULD NOT BE SURPRISED IF CONDITIONS ENDED UP WORSE...ESPECIALLY CEILINGS WHICH MAY END UP BEING 500 FEET. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....DG AVIATION.....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1149 AM EST SAT NOV 26 2005 .UPDATE...RELATIVELY BENIGN WEATHER ACROSS NORTHERN MICHIGAN TODAY WITH SFC HIGH PRESSURE ACROSS THE REGION. NONETHELESS...A FEW INTERESTING ITEMS TO TALK ABOUT. FIST OFF...LINGERING LAKE CONVECTION STILL PRESENT ACROSS NRN LAKE MICHIGAN. EARLY MORNING LAND BREEZE COMPONENT ABLE TO PUSH MOST OF THE CONVECTION OFFSHORE. HOWEVER...UNDER THE LIGHT WIND REGIME...RADAR RETURN PATTERN AND VISIBLE SATELLITE IMAGERY REVEALING A SMALL LAKE VORTEX TAKING SHAPE ACROSS FAR NRN LAKE MICHIGAN...BEGINNING TO DRIFT NORTH INTO WESTERN MACK COUNTY. MEANWHILE...12Z UPPER CHARTS SHOWING WEAK MID LEVEL WARM ADVECTION MAX AND TIGHT THERMAL GRADIENT DRAPED OUT ACROSS NRN MICHIGAN. SATELLITE IMAGERY REVEALING ASSOCIATED BAND OF MID CLOUD STRETCHING ACROSS CENTRAL LOWER MICHIGAN...WHILE KAPX RADAR SHOWING A BROAD AREA OF VERY LIGHT MID LEVEL RETURNS ACROSS THIS AREA AND A FEW FLURRIES REPORTED IN SFC OBS (CAD REPORTED -SN THROUGH 14Z OR SO). RADAR RETURN PATTERN BEGINNING TO SHRINK UP HOWEVER AS BULK OF SYNOPTIC MOISTURE CONTINUES TO THIN OUT. FOR THE AFTERNOON...WARM ADVECTION EXPECTED TO CONTINUE THIS AFTERNOON THROUGH TONIGHT SHIFTING INTO THE LOWER LEVELS AS WE HEAD INTO THE EVENING. HOWEVER...MODEL AND SATELLITE DATA BOTH SUGGEST SYNOPTIC MOISTURE WILL CONTINUE TO THIN OUT THROUGH THE AFTERNOON AND WE SHOULD SEE AN END TO LIGHT SNOW/FLURRIES WITH INCREASING SUNSHINE ACROSS LOWER MICHIGAN. BUT...WILL STRETCH THE SMALL CHANCE FOR LIGHT SNOW/FLURRIES ACROSS THE SOUTHERN COUNTIES INTO THE EARLY AFTERNOON HOURS TO COVER WHAT/S LEFT. SECONDLY...LAKE CONVECTION. THERMODYNAMICALLY SPEAKING CONDITIONS STILL DECENT FOR LAKE EFFECT...WITH 850 MB TEMP OF -12C ON MORNING APX SOUNDING...SUFFICIENT DELTA T/S AND RESPECTABLE REGIME FOR LARGE SNOWFLAKES. UNDER LIGHT SOUTHERLY FLOW...LAKE VORTEX OVER NRN LAKE MICHIGAN HAS A WINDOW OF OPPORTUNITY THIS AFTERNOON TO PRODUCE DECENT SNOWFALL RATES AS IT DRIFTS UP INTO WESTERN MACK COUNTY. THESE FEATURES ALWAYS TRICKY AS THEY CAN QUICKLY RACK UP ADVISORY CRITERIA ACCUMULATIONS. BUT GIVEN THE THINNING SYNOPTIC MOISTURE AND FORECAST WARMING IN THE LOWER LAYERS...DON/T THINK THIS WILL BE THE CASE TODAY. WILL HOWEVER EXPAND LIKELY POPS ACROSS ALL OF WESTERN MACK COUNTY FOR THE AFTERNOON WITH AROUND AN INCH OF ACCUMULATION. BUT WILL NEED TO MONITOR PROGRESS OF THIS FEATURE AND MAKE A FEW CALLS THIS AFTERNOON TO SEE WHAT/S GOING ON. ADAM && .PREV DISCUSSION...ISSUED AT 810 AM EST SAT NOV 26 2005 UPDATE...CANCELED LAKE EFFECT SNOW ADVISORY AND WARNING FOR CHARLEVOIX AND EMMET COUNTIES. LAKE EFFECT SNOW BANDS PULLED OFFSHORE AND NO LONGER POSE A THREAT FOR ACCUMULATING LAKE EFFECT SNOW. SCATTERED LIGHT SNOW SHOWERS WILL HOWEVER...STILL AFFECT THE IMMEDIATE LAKESHORE AREAS AROUND NRN LAKE MICHIGAN AND LAKE HURON. && .PREV DISCUSSION ISSUED AT 445 AM SAT NOV 26 2005.... DISCUSSION...SFC/SATELLITE/RUC AND UPPER AIR ANALYSIS SHOWING BROAD UPPER TROUGH ENGULFING THE NE CONUS WITH RIDGING EXITING THE ROCKIES IN ADVANCE OF ANOTHER UPPER TROUGH NOW PLOWING INTO THE PAC NW. SRN STREAM SHORTWAVE TROUGH ALSO EVIDENT ACROSS SRN TEXAS. SFC LOW PRESSURE SEEN DEVELOPING IN THE LEE OF THE ROCKIES...WITH A WARM FRONT EXTENDING FROM NRN NE...INTO CENTRAL IL/INDY. ISENTROPIC ASCENT/WAA NORTH OF THE WARM FRONT HAS BEEN PRODUCING LIGHT SNOWS ACROSS CENTRAL/SRN LOWER MICHIGAN...ENHANCED BY SEVERAL FAVORABLE LAKE EFFECT PARAMETERS. HIGH PRESSURE RESIDED ON THE EAST COAST... AND OUTSIDE OF LAKE TROUGHING ACROSS THE GREAT LAKES...RIDGE AXIS STRETCHED BACK ACROSS THE CWA. SOME OF THE LIGHT WAA SNOWS WERE SCRAPING THE SRN CWA WITH 3-5SM VISIBILITIES...BUT THE ADDITIONAL MID LEVEL MOISTURE SEEN ON SATELLITE (AHEAD OF VORT MAX IN CENTRAL UPPER) ARE CERTAINLY AIDING THE SNOWFALL INTENSITIES IN LIGHT (10KT) SW FLOW/LAKE EFFECT BANDS THAT WERE HUGGING OUR OUR LAKE MICHIGAN SHORELINE. RADAR HAS BEEN HINTING AT LAKE EFFECT TRYING TO MOVE OFFSHORE IN SOME LOCALES AS THE WIND REGIME IS LIGHT AND EXPECTED TO WEAKEN A BIT FURTHER. SO...WITH THE NORTHWARD ADVECTION OF THE MID LEVEL MOISTURE...ONE HAS TO ASK THE QUESTION...WHAT WILL BE THE NET SNOWFALL TOTALS FOR THOSE AREAS IN THE ADVISORIES/WARNINGS ALONG THE LAKE MICHIGAN SHORE? AND TO THROW IN ANOTHER WRENCH INTO THE FORECAST...WILL MID LAKE VORTICES HAVE ANY IMPACT ON NRN MICHIGAN WEATHER?...AS THERE IS ONE SPINNING OUT OVER WHITEFISH BAY ATTM. THIS JUST ONE OF THE CONCERNS IN THIS FORECAST PACKAGE. ADDITIONAL FORECAST CONCERNS...INCLUDE ENDING THE WAA SNOWFALL TODAY...AND DO WE END LAKE EFFECT TODAY AS WINDS SHIFT MORE SRLY/MAYBE SOUTHEASTERLY WITH WARM FRONT MOVING NORTHWARD? THAT IS JUST TODAY. TONIGHT ONWARD...WE ARE FACED WITH PRECIP CONCERNS BEGINNING AS DRIZZLE OR FREEZING DRIZZLE LATE TONIGHT BEFORE DEEPER MOISTURE ADVECTS IN AND PRECIP AND FOG ISSUES BEGIN IN EARNEST. COLDER AIR WRAPS BACK IN BEHIND STRONG SFC LOW (CULPRIT OF THE RAIN CHANCES) MONDAY/MONDAY NIGHT FOR SNOW TO ENTER THE FORECAST AGAIN. THE UP AND DOWN WEATHER SAGA OF NRN MICHIGAN CONTINUES. TODAY...CURRENT LIGHT SNOWFALL IN ISENTROPIC REGIME ON THE 295K SFC CONTINUES TO SLOWLY INCREASE ACROSS THE CWA IN INCREASING H7-H5 -DIVQ AHEAD OF SHORTWAVE WHICH WILL SHOOT THROUGH THE TIP OF THE MITT THIS MORNING. SATELLITE VERIFIES THAT MID LEVEL MOISTURE WILL GET STRIPPED OUT BY 12Z THIS MORNING...BUT NORTHWARD EXPANSION OF THIS RH HAS LED TO INTENSIFICATION OF THE SW SNOW BANDS CLINGING TO THE LAKE MICHIGAN SHORELINE. REPORT OUT OF MANISTEE HAS RESULTED IN NEAR 6 INCHES OF SNOWFALL...AND HAS LED TO A HEAVY SNOW WARNING FOR MANISTEE AND LEELANAU COUNTIES DURING THE OVERNIGHT HOURS. BANDS STILL LOOK LIKE THEY ARE TRYING TO SNEAK OFFSHORE...THE TREND BEING SET FROM THE SOUTH AROUND MANISTEE. WINDS WILL SHIFT MORE FROM THE SOUTH EARLY THIS MORNING..AND WHEN COMBINED WITH THE LAND BREEZE COMPONENT...SHOULD RESULT IN CHIPPEWA SEEING NO FURTHER TROUBLES WITH LAKE EFFECT. WILL END ADVISORIES AT FORECAST ISSUANCE. FOR EMMET WILL HAVE TO WATCH RADAR AND SEE...AS IT IS A TIMING ISSUE WITH MOISTURE AND LAND BREEZE. FOR MACKINAC COUNTY OF EASTERN UPPER IT IS A BIT MORE DIFFICULT. SRN PORTIONS AROUND SAINT IGNACE HAVE ALREADY BEEN GETTING SNOW AND WINDS WILL BE TURNING MORE SOUTHERLY. HOWEVER...LAND BREEZE MORE DEVELOPED IN THIS AREA...AND MOISTURE WILL BE STRIPPING OUT BY 12Z. WILL ALSO HAVE TO WATCH FOR MID LAKE VORTICES OVER THE NRN LAKES...OF WHICH MIXING INTO A SOUTHERLY FLOW COULD BRING A BRIEF SHOT OF HEAVY SNOW INTO THE WESTERN PART OF THE COUNTY. FEELING IS THAT I WILL NEED TO EXTEND LAKE EFFECT SNOW ADVISORIES FOR MACKINAC COUNTY INTO A FEW HOURS AFTER DAYBREAK THIS MORNING...AS WELL AS THE LES WARNING FOR EMMET...AS LONG AS RADAR STILL SHOWS BANDS MAKING IT INLAND...BECAUSE WITH H8 TEMPS STILL >12C THROUGH 18Z...H9-H7 RH >75% THROUGH 15Z ALONG EXTERNAL FORCING AHEAD OF AFOREMENTIONED SHORTWAVE...HEAVIER SNOW CAN CONTINUE. THE OVERALL TREND BY AFTERNOON WILL BE A DECREASE IN ACTIVITY. THIS ESPECIALLY TRUE BY LATE AFTERNOON...AS AN EASTERLY COMPONENT IS THROWN IN...AND FETCH LENGTHS ARE SHORT...AND MOISTURE IS DOWN TO 50-60% AT H9-H7. GOING BACK TO THE ISENTROPIC ASCENT/LIGHT SNOWS... LOOK FOR AN END ACROSS THE NE LOWER BY LATE MORNING. SNOWFALL ACCUMULATIONS WITH THIS WILL BE LIGHT...STRUGGLING TO GET AN INCH EXCEPT FOR THE MOST SRN AREAS OF THE CWA...MAINLY SOUTH OF M-55. BEST WARMING DOES NOT ARRIVE THIS AFTERNOON WITH WARM FRONT STILL TO OUR SOUTH...HIGHS WITH THE SNOW COVER WILL BE COOL...IN THE TONIGHT AND SUNDAY...1000-850MB FLOW SLIGHTLY EAST OF SOUTH THIS EVENING...AND THERE WILL BE A BRIEF PERIOD WHERE OVER LAKE INSTABILITY REMAINS SUFFICIENT BEFORE STRONG WARMING ENSUES WITH ARRIVAL OF WARM FRONT. WILL CARRY A SMALL CHANCE OF SCATTERED FLURRIES FOR SOUTHERN MACKINAC COUNTY. OTHERWISE...WE WILL HAVE A BRIEF LULL IN WEATHER UNTIL THE LATE HOURS PAST MIDNIGHT WHEN LOW LEVEL MOISTURE SURGES IN WITH THE WARM FRONT...WITH SATURATION OCCURRING UP TO 5-6KFT AND SOME SHEAR NOTED OF FORECAST SOUNDINGS AT THE TOP OF THIS MOIST LAYER. THE ENTIRE MOIST LAYER WILL BE ABOVE FREEZING UNDER THE RAPID WARMING...WHILE SFC TEMPS WILL HAVE RISEN TO THE UPPER 20S AND LOWER HALF OF THE 30S BY DAYBREAK. CAN SEE MOST AREAS WITH PATCHY FREEZING DRIZZLE LATE TONIGHT WITH THE EXCEPTION FOR SOME OF THE COASTAL AREAS THAT GET AN ADDED BOOST IN TEMP DUE TO THE WARMER LAKES. THIS SHOULD BE A RATHER BRIEF PERIOD OF DRIZZLE HOWEVER...AS AFOREMENTIONED SRN STREAM TROUGH (OUT OF SRN TEXAS) LIFTS NORTHEASTWARD AND GET ENTANGLED WITH SHARPENING UPPER TROUGH EXITING THE ROCKIES. CYCLOGENESIS ENSUES...AND DEEP SOUTHERLY FLOW DEVELOPS WITH THE GULF OF MEXICO WIDE OPEN. TREMENDOUS MOISTURE TRANSPORT IS SEEN COMING INTO NRN MICHIGAN WITH PWATS AROUND AN INCH BY AFTERNOON. WENT AHEAD AND WENT CATEGORICAL WITH THE PRECIP CHANCES (IT WILL RAIN)...AND STARTED IT SOONER...BY MID/LATE MORNING. LOTS OF SNOW COVER TO GET RID OF...AND BETWEEN MELTING AND SFC TD'S RISING INTO THE UPPER 30S (POSSIBLY LOW 40S)...FOG LOOKS LIKE A VERY GOOD BET. DID NOT THROW IN MENTION OF DENSE FOG JUST YET...BUT CAN SEE IT ENTERING THE FORECAST IN THE NEXT COUPLE OF FORECAST ISSUANCES. SUNDAY NIGHT...THERE ARE QUESTIONS REVOLVING AROUND WHAT PRECIP CHANCES ARE IN THIS PERIOD. DEEPER MOISTURE/LIFT...AS IT STANDS RIGHT NOW...REMAIN ACROSS EASTERN UPPER IN THE EVENING...BUT WE WILL HAVE SOME AMOUNT OF DRY SLOTTING ARRIVING DURING THE NIGHT. COULD SEE A CHANGE BACK TO DRIZZLE IN SOME AREAS...BUT WE WILL ALSO BE ON THE VERGE OF ANOTHER SHOT OF DEEPER MOISTURE SCRAPING AT THE WESTERN CWA BY DAYBREAK. WILL THEREFORE KEEP LIKELY CHANCES OF RAIN ATTM. IT WILL AT LEAST BE DAMP/WET AND PRECIP LOOKS LIKELY FOR AT LEAST A PERIOD OF TIME FOR ALL AREAS. FOG WORDING TO REMAIN IN THE FORECAST FOR SURE. MONDAY ONWARD...MODELS REMAIN IN DECENT AGREEMENT WITH LIFTING UPPER LOW CENTER/TROUGH ACROSS NRN MICHIGAN BY TUESDAY MORNING. SFC LOW PASSES TO OUR NW MONDAY NIGHT. THERE LOOKS TO BE A TIME OF DRYING ALOFT (POSSIBLY BRINGING DRIZZLE BACK INTO THE PICTURE)...BEFORE COLDER AIR CONTINUING TO ADVECT INTO TUESDAY FOR A CHANGE TO RAIN AND SNOW LATE MONDAY NIGHT...THEN JUST SNOW CHANCES FOR TUESDAY. NO OTHER CHANGES TO THE FORECAST. SMD && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1036 AM EST SAT NOV 26 2005 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC/NAM SHOWING LONGWAVE TROUGH EXTENDING FROM A LOW OVER HUDSON BAY SOUTH INTO THE UPPER GREAT LAKES. A WEAK SHORTWAVE ROTATING THROUGH THE BASE OF THIS TROUGH IS SLIDING ACROSS EASTERN U.P. A RIDGE OVER THE DAKOTAS IS PUSHING THIS SHORTWAVE EAST. SURFACE ANALYSIS SHOWING A LOW OVER WESTERN NEBRASKA WITH A WARM FRONT EXTENDING EAST THROUGH IOWA INTO NORTHERN OHIO RIVER VALLEY. LAKE-850MB DELTA-T'S OVER LAKE SUPERIOR THIS MORING ARE AROUND 16C. THIS IS SUFFICIENT LOW LEVEL LAPSE RATES TO PRODUCE LAKE EFFECT SNOWS...WHICH ACCORDING TO KMQT-88D AND VISIBILE SATELLITE SHOW ARE OCCURRING OVER EASTERN LAKES SUPERIOR. THE WINDS OVER EASTERN LAKE SUPERIOR ARE OUT OF THE SOUTHEAST AND ARE MOVING THESE SHOWERS NORTHWEST. ANOTHER AREA OF LAKE EFFECT SNOW SHOWERS ARE OVER THE NORTHERN BAY OF GREEN BAY AND NORTHERN LAKE MICHIGAN. THE SHORTWAVE OVER THE EASTERN U.P. WILL EDGE INTO EASTERN ONTARIO THIS AFTERNOON. ANOTHER WEAK SHORTWAVE IS EXPECTED TO SHIFT SOUTHEAST ALONG THE NORTHEAST SHORE OF LAKE SUPERIOR. DELTA-T'S WILL LOWER BY 2C THIS AFTERNOON. LOW LEVEL CONVERGENCE WILL CONTINUE OVER EASTERN LAKE SUPERIOR. LOW LEVEL WINDS WILL REMAIN OUT OF THE SOUTH. THUS LES SHOULD CONTINUE OVER NORTHERN LAKE MICHIGAN AND THE NORTHERN BAY OF GREEN BAY. THIS WILL SPREAD INTO EASTERN U.P. OTHERWISE...DRY CONDITIONS WILL PREVAIL ACROSS MOST OF THE REST OF THE FORECAST AREA THIS AFTERNOON. WHAT SNOW DOES OCCUR WILL BE LIGHT AS THERE WILL BE VERY LITTLE LOW LEVEL CONVERGENCE. I PLAN TO MAKE VERY LITTLE CHANGES TO THE GOING FORECAST...MAINLY TWEAKING THE FIRST PERIOD WORDING. THE OVERNIGHT FORECAST WILL BE A LITTLE MORE COMPLICATED MAINLY WITH THE POTENTIAL FOR FOG/DRIZZLE AND LOW CLOUDS. THIS I WILL LEAVE UNTIL I HAVE HAD A BETTER LOOK AT THE NEW MODELS. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 810 AM EST SAT NOV 26 2005 .UPDATE...CANCELED LAKE EFFECT SNOW ADVISORY AND WARNING FOR CHARLEVOIX AND EMMET COUNTIES. LAKE EFFECT SNOW BANDS PULLED OFFSHORE AND NO LONGER POSE A THREAT FOR ACCUMULATING LAKE EFFECT SNOW. SCATTERED LIGHT SNOW SHOWERS WILL HOWEVER...STILL AFFECT THE IMMEDIATE LAKESHORE AREAS AROUND NRN LAKE MICHIGAN AND LAKE HURON. && .PREV DISCUSSION ISSUED AT 445 AM SAT NOV 26 2005.... DISCUSSION...SFC/SATELLITE/RUC AND UPPER AIR ANALYSIS SHOWING BROAD UPPER TROUGH ENGULFING THE NE CONUS WITH RIDGING EXITING THE ROCKIES IN ADVANCE OF ANOTHER UPPER TROUGH NOW PLOWING INTO THE PAC NW. SRN STREAM SHORTWAVE TROUGH ALSO EVIDENT ACROSS SRN TEXAS. SFC LOW PRESSURE SEEN DEVELOPING IN THE LEE OF THE ROCKIES...WITH A WARM FRONT EXTENDING FROM NRN NE...INTO CENTRAL IL/INDY. ISENTROPIC ASCENT/WAA NORTH OF THE WARM FRONT HAS BEEN PRODUCING LIGHT SNOWS ACROSS CENTRAL/SRN LOWER MICHIGAN...ENHANCED BY SEVERAL FAVORABLE LAKE EFFECT PARAMETERS. HIGH PRESSURE RESIDED ON THE EAST COAST... AND OUTSIDE OF LAKE TROUGHING ACROSS THE GREAT LAKES...RIDGE AXIS STRETCHED BACK ACROSS THE CWA. SOME OF THE LIGHT WAA SNOWS WERE SCRAPING THE SRN CWA WITH 3-5SM VISIBILITIES...BUT THE ADDITIONAL MID LEVEL MOISTURE SEEN ON SATELLITE (AHEAD OF VORT MAX IN CENTRAL UPPER) ARE CERTAINLY AIDING THE SNOWFALL INTENSITIES IN LIGHT (10KT) SW FLOW/LAKE EFFECT BANDS THAT WERE HUGGING OUR OUR LAKE MICHIGAN SHORELINE. RADAR HAS BEEN HINTING AT LAKE EFFECT TRYING TO MOVE OFFSHORE IN SOME LOCALES AS THE WIND REGIME IS LIGHT AND EXPECTED TO WEAKEN A BIT FURTHER. SO...WITH THE NORTHWARD ADVECTION OF THE MID LEVEL MOISTURE...ONE HAS TO ASK THE QUESTION...WHAT WILL BE THE NET SNOWFALL TOTALS FOR THOSE AREAS IN THE ADVISORIES/WARNINGS ALONG THE LAKE MICHIGAN SHORE? AND TO THROW IN ANOTHER WRENCH INTO THE FORECAST...WILL MID LAKE VORTICES HAVE ANY IMPACT ON NRN MICHIGAN WEATHER?...AS THERE IS ONE SPINNING OUT OVER WHITEFISH BAY ATTM. THIS JUST ONE OF THE CONCERNS IN THIS FORECAST PACKAGE. ADDITIONAL FORECAST CONCERNS...INCLUDE ENDING THE WAA SNOWFALL TODAY...AND DO WE END LAKE EFFECT TODAY AS WINDS SHIFT MORE SRLY/MAYBE SOUTHEASTERLY WITH WARM FRONT MOVING NORTHWARD? THAT IS JUST TODAY. TONIGHT ONWARD...WE ARE FACED WITH PRECIP CONCERNS BEGINNING AS DRIZZLE OR FREEZING DRIZZLE LATE TONIGHT BEFORE DEEPER MOISTURE ADVECTS IN AND PRECIP AND FOG ISSUES BEGIN IN EARNEST. COLDER AIR WRAPS BACK IN BEHIND STRONG SFC LOW (CULPRIT OF THE RAIN CHANCES) MONDAY/MONDAY NIGHT FOR SNOW TO ENTER THE FORECAST AGAIN. THE UP AND DOWN WEATHER SAGA OF NRN MICHIGAN CONTINUES. TODAY...CURRENT LIGHT SNOWFALL IN ISENTROPIC REGIME ON THE 295K SFC CONTINUES TO SLOWLY INCREASE ACROSS THE CWA IN INCREASING H7-H5 -DIVQ AHEAD OF SHORTWAVE WHICH WILL SHOOT THROUGH THE TIP OF THE MITT THIS MORNING. SATELLITE VERIFIES THAT MID LEVEL MOISTURE WILL GET STRIPPED OUT BY 12Z THIS MORNING...BUT NORTHWARD EXPANSION OF THIS RH HAS LED TO INTENSIFICATION OF THE SW SNOW BANDS CLINGING TO THE LAKE MICHIGAN SHORELINE. REPORT OUT OF MANISTEE HAS RESULTED IN NEAR 6 INCHES OF SNOWFALL...AND HAS LED TO A HEAVY SNOW WARNING FOR MANISTEE AND LEELANAU COUNTIES DURING THE OVERNIGHT HOURS. BANDS STILL LOOK LIKE THEY ARE TRYING TO SNEAK OFFSHORE...THE TREND BEING SET FROM THE SOUTH AROUND MANISTEE. WINDS WILL SHIFT MORE FROM THE SOUTH EARLY THIS MORNING..AND WHEN COMBINED WITH THE LAND BREEZE COMPONENT...SHOULD RESULT IN CHIPPEWA SEEING NO FURTHER TROUBLES WITH LAKE EFFECT. WILL END ADVISORIES AT FORECAST ISSUANCE. FOR EMMET WILL HAVE TO WATCH RADAR AND SEE...AS IT IS A TIMING ISSUE WITH MOISTURE AND LAND BREEZE. FOR MACKINAC COUNTY OF EASTERN UPPER IT IS A BIT MORE DIFFICULT. SRN PORTIONS AROUND SAINT IGNACE HAVE ALREADY BEEN GETTING SNOW AND WINDS WILL BE TURNING MORE SOUTHERLY. HOWEVER...LAND BREEZE MORE DEVELOPED IN THIS AREA...AND MOISTURE WILL BE STRIPPING OUT BY 12Z. WILL ALSO HAVE TO WATCH FOR MID LAKE VORTICES OVER THE NRN LAKES...OF WHICH MIXING INTO A SOUTHERLY FLOW COULD BRING A BRIEF SHOT OF HEAVY SNOW INTO THE WESTERN PART OF THE COUNTY. FEELING IS THAT I WILL NEED TO EXTEND LAKE EFFECT SNOW ADVISORIES FOR MACKINAC COUNTY INTO A FEW HOURS AFTER DAYBREAK THIS MORNING...AS WELL AS THE LES WARNING FOR EMMET...AS LONG AS RADAR STILL SHOWS BANDS MAKING IT INLAND...BECAUSE WITH H8 TEMPS STILL >12C THROUGH 18Z...H9-H7 RH >75% THROUGH 15Z ALONG EXTERNAL FORCING AHEAD OF AFOREMENTIONED SHORTWAVE...HEAVIER SNOW CAN CONTINUE. THE OVERALL TREND BY AFTERNOON WILL BE A DECREASE IN ACTIVITY. THIS ESPECIALLY TRUE BY LATE AFTERNOON...AS AN EASTERLY COMPONENT IS THROWN IN...AND FETCH LENGTHS ARE SHORT...AND MOISTURE IS DOWN TO 50-60% AT H9-H7. GOING BACK TO THE ISENTROPIC ASCENT/LIGHT SNOWS... LOOK FOR AN END ACROSS THE NE LOWER BY LATE MORNING. SNOWFALL ACCUMULATIONS WITH THIS WILL BE LIGHT...STRUGGLING TO GET AN INCH EXCEPT FOR THE MOST SRN AREAS OF THE CWA...MAINLY SOUTH OF M-55. BEST WARMING DOES NOT ARRIVE THIS AFTERNOON WITH WARM FRONT STILL TO OUR SOUTH...HIGHS WITH THE SNOW COVER WILL BE COOL...IN THE TONIGHT AND SUNDAY...1000-850MB FLOW SLIGHTLY EAST OF SOUTH THIS EVENING...AND THERE WILL BE A BRIEF PERIOD WHERE OVER LAKE INSTABILITY REMAINS SUFFICIENT BEFORE STRONG WARMING ENSUES WITH ARRIVAL OF WARM FRONT. WILL CARRY A SMALL CHANCE OF SCATTERED FLURRIES FOR SOUTHERN MACKINAC COUNTY. OTHERWISE...WE WILL HAVE A BRIEF LULL IN WEATHER UNTIL THE LATE HOURS PAST MIDNIGHT WHEN LOW LEVEL MOISTURE SURGES IN WITH THE WARM FRONT...WITH SATURATION OCCURRING UP TO 5-6KFT AND SOME SHEAR NOTED OF FORECAST SOUNDINGS AT THE TOP OF THIS MOIST LAYER. THE ENTIRE MOIST LAYER WILL BE ABOVE FREEZING UNDER THE RAPID WARMING...WHILE SFC TEMPS WILL HAVE RISEN TO THE UPPER 20S AND LOWER HALF OF THE 30S BY DAYBREAK. CAN SEE MOST AREAS WITH PATCHY FREEZING DRIZZLE LATE TONIGHT WITH THE EXCEPTION FOR SOME OF THE COASTAL AREAS THAT GET AN ADDED BOOST IN TEMP DUE TO THE WARMER LAKES. THIS SHOULD BE A RATHER BRIEF PERIOD OF DRIZZLE HOWEVER...AS AFOREMENTIONED SRN STREAM TROUGH (OUT OF SRN TEXAS) LIFTS NORTHEASTWARD AND GET ENTANGLED WITH SHARPENING UPPER TROUGH EXITING THE ROCKIES. CYCLOGENESIS ENSUES...AND DEEP SOUTHERLY FLOW DEVELOPS WITH THE GULF OF MEXICO WIDE OPEN. TREMENDOUS MOISTURE TRANSPORT IS SEEN COMING INTO NRN MICHIGAN WITH PWATS AROUND AN INCH BY AFTERNOON. WENT AHEAD AND WENT CATEGORICAL WITH THE PRECIP CHANCES (IT WILL RAIN)...AND STARTED IT SOONER...BY MID/LATE MORNING. LOTS OF SNOW COVER TO GET RID OF...AND BETWEEN MELTING AND SFC TD'S RISING INTO THE UPPER 30S (POSSIBLY LOW 40S)...FOG LOOKS LIKE A VERY GOOD BET. DID NOT THROW IN MENTION OF DENSE FOG JUST YET...BUT CAN SEE IT ENTERING THE FORECAST IN THE NEXT COUPLE OF FORECAST ISSUANCES. SUNDAY NIGHT...THERE ARE QUESTIONS REVOLVING AROUND WHAT PRECIP CHANCES ARE IN THIS PERIOD. DEEPER MOISTURE/LIFT...AS IT STANDS RIGHT NOW...REMAIN ACROSS EASTERN UPPER IN THE EVENING...BUT WE WILL HAVE SOME AMOUNT OF DRY SLOTTING ARRIVING DURING THE NIGHT. COULD SEE A CHANGE BACK TO DRIZZLE IN SOME AREAS...BUT WE WILL ALSO BE ON THE VERGE OF ANOTHER SHOT OF DEEPER MOISTURE SCRAPING AT THE WESTERN CWA BY DAYBREAK. WILL THEREFORE KEEP LIKELY CHANCES OF RAIN ATTM. IT WILL AT LEAST BE DAMP/WET AND PRECIP LOOKS LIKELY FOR AT LEAST A PERIOD OF TIME FOR ALL AREAS. FOG WORDING TO REMAIN IN THE FORECAST FOR SURE. MONDAY ONWARD...MODELS REMAIN IN DECENT AGREEMENT WITH LIFTING UPPER LOW CENTER/TROUGH ACROSS NRN MICHIGAN BY TUESDAY MORNING. SFC LOW PASSES TO OUR NW MONDAY NIGHT. THERE LOOKS TO BE A TIME OF DRYING ALOFT (POSSIBLY BRINGING DRIZZLE BACK INTO THE PICTURE)...BEFORE COLDER AIR CONTINUING TO ADVECT INTO TUESDAY FOR A CHANGE TO RAIN AND SNOW LATE MONDAY NIGHT...THEN JUST SNOW CHANCES FOR TUESDAY. NO OTHER CHANGES TO THE FORECAST. SMD && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 913 PM CST SAT NOV 26 2005 .UPDATE... LO CLDS/PCPN HAVING A DIFFICULT TIME GETTING GOING THIS EVE IN VICINITY OF THE WARM FRONT...CURRENTLY STRETCHING FROM W CNTRL KS ENEWRD THRU CNTRL IA. CURRENT SPLIT CHANNEL SAT IMAGERY SHOWING A FEW POCKETS OF LOWER CLDS ACRS ERN NE AND CNTRL IA...BUT SFC OBS SHOWING CEILINGS/MIN CLD HTS OF ONLY ABOUT 3 KFT. TEMPS ACRS THE FA HAVE BEEN SLOWLY DROPPING...WITH THE WARM FRONT MAKING ONLY SLGT NWRD PROGRESS AND THE LO CLDS SLOW TO DEVELOP. EXPECT THIS TREND WILL CONT UNTIL BOTH OF THESE TRENDS ARE REVERSED. THE 00Z NAM/RUC SOLNS SHOW THE MAX H10-H8 TEMP ADVECTION MOVING NWRD INTO THE FA AROUND MIDNGT...AND THEREFORE...HAVE ADJUSTED HRLY TEMP GRIDS /WHICH ALREADY INCLUDED A RISING TREND/ ACCORDING TO THE LOWER TEMPS THAN FCST THAT ARE CURRENTLY IN THE SFC OBS. REGARDING TNGT'S PCPN SITUATION...HAVE DELAYED THE START TIME FOR THE PCPN IN THE S CNTRL MN AND W CNTRL WI AREAS UNTIL 09Z...IN PART DUE TO THE AFOREMENTIONED LACK OF LO CLDS IN IA. THE DELAY IS SUPPORTED BY THE 00Z NAM/RUC 285K ISEN ANALYSES...WHICH DO NOT SHOW AN AREA OF LOWER CONDENSATION PRES DEFICITS ENTERING THE FA PRIOR TO THIS TIME. IN ADDITION...A BULLSEYE OF H7 OMEGA PUSHES THRU SERN MN AND INTO W CNTRL AND NWRN WI TOWARD MRNG...WHICH IS COINCIDENT WITH A MAX IN H8-H7 TEMP ADVECTION. THE RELATIVE LACK OF FORCING PRIOR TO THE MRNG HRS ACRS THE W CNTRL AND NWRN MN COUNTIES HAS LED TO THE DELETION OF THE POPS IN THIS RGN. IMMEDIATELY N AND W OF THE MEASURABLE PCPN RGN...HOWEVER...HAVE INCLUDED A NARROW BAND OF DZ/FZDZ...WHICH BEGINS ACRS S CNTRL MN AND PARTS OF W CNTRL WI PRIOR TO THE 09Z TIME PD. THIS IS SUPPORTED BY THE 00Z KMPX RAOB...WHICH SHOWS A NARROW SATURATED AREA AT APPROX THE 900 MB LAYER. AS THE WARM FRONT APPROACHES AND GIVES A LITTLE KICK TO THIS SATURATED LAYER...EXPECT SOME AREAS OF DZ/FZDZ TO DEVELOP. THE LACK OF MID LEVEL MOISTURE ATTM...LEADS TO THE INCLUSION OF DZ/FZDZ RATHER THAN RA/FZRA. && .PREV DISCUSSION... /ISSUED 420 PM CST SAT NOV 26 2005/ DISCUSSION... CONCERN TONIGHT IS WITH WARM FRONT THAT WILL MOVE NWARD THRU ZONES WHICH COULD TRIGGER SOME LIGHT PRECIP. SFC TEMPS N OF BDRY IN MID 20S TO LOWER 30S...AND AS BDRY SWINGS THRU TONIGHT TEMPS WILL START TO RISE AFT MIDNIGHT. ITS ALL IN THE TIMING OF WHEN A PARTICULAR LOCATION GETS ABOVE FREEZING VS START OF LIGHT PRECIP WHETHER IT WILL BE IN THE FORM OF RAIN OR FZRA. HAVE MENTIONED 30 POPS CWA WIDE FOR RAIN...WITH CHANCE FZRA WORDING IN AREAS THAT WILL BE AT OR BELOW FREEZING THRESHOLD AT TIME WHEN PRECIP EXPECTED TO BEGIN...GENERALLY AFT 06Z. LIFT AHEAD OF APPG LOW OVER NEB WILL SWING INTO CWA SUN MORN BRINGING WIDESPREAD RAIN BY AFT. IN MORNING ACROSS FAR N/NW ZONES THERE MAY BE A FEW HRS WHERE TEMPS HOVER AROUND FREEZING SO CONTINUE TO MENTION THREAT OF FZRA THERE THRU 15Z. AMPLE LIFT AND MOISTURE OVER CWA INTO SUN NIGHT WHEN THICKNESS FIELDS SHOW CHANGEOVER TO SNOW POSSIBLE WRN MN BY 09Z MON AND WRN 1/3 CWA BETWEEN 12Z AND 15Z MON. HAVE ISSUED WINTER STORM WATCH FOR THESE AREAS SINCE SNOW WILL BE PRIMARY WX IN THIS AREA FOR MUCH OF MONDAY INTO MON EVE...ACCUMULATIONS OF 6 TO 8 INCHES EXPECTED W OF A LINE FROM STAPLES TO GRANITE FALLS...WITH 4 TO 6 INCHES W OF A LINE FROM MILLE LACS LAKE TO ST CLOUD TO LITCHFIELD TO SLEEPY EYE. E OF THIS LINE THICKNESS FIELDS CONTINUE TO SHOW A LONG TIME BEFORE COMPLETE CHANGEOVER OCCURS DUE TO MAINLY NWARD MOVEMENT OF 500/700MB LOW BISECTING ZONES. EXPECT ACCUMULATIONS TO RANGE E OF WATCH BETWEEN 1 TO 3 INCHES...MAINLY OCCURING MON NIGHT. ALSO OF ISSUE MON IS GUSTY WINDS OF 25 TO 35 MPH WHICH WILL BLOW ACCUMULATING SNOW AROUND INTO THE EVE HRS...ESPECIALLY IN WRN HALF OF CWA. PRECIP TAPERS OFF QUICKLY FROM W TO E TUE MORN AS LOW WEAKENS AND PUSHES INTO UP OF MI. LONGER TERM...TUESDAY NIGHT THROUGH SATURDAY THE POLAR JET STREAM IS FORECAST BY THE GFS MODEL TO REMAIN SOUTH OF OUR FORECAST AREA TUESDAY NIGHT INTO FRIDAY. THIS LEAVES US IN A COLD REGIME. MINUS 18 DEGREE 850 TEMPERATURES ARE FORECAST TO MOVE OVER THURSDAY NIGHT INTO FRIDAY. THIS COLD AIR PRECEDES A MID TO UPPER LEVEL TROUGH AND AN ACCOMPANYING COLD FRONT THAT WILL BRING A CHANCE OF SNOW WEDNESDAY INTO EARLY THURSDAY. A SURFACE RIDGE IS FORECAST TO MOVE ACROSS THE AREA FRIDAY AND A 500 MB RIDGE IS EXPECTED TO FOLLOW FRIDAY NIGHT. THIS SETS THE STAGE FOR THE RETURN OF SOUTHWEST FLOW ALOFT SATURDAY WITH LOW TO MID LEVEL WARM ADVECTION. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY EVENING FOR CHIPPEWA-DOUGLAS-LAC QUI PARLE-POPE-STEVENS-SWIFT-TODD- YELLOW MEDICINE. WINTER STORM WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR BENTON-BROWN-KANDIYOHI-MEEKER-MORRISON-REDWOOD-RENVILLE- STEARNS. WI...NONE. && $$ KAT mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 953 AM CST SAT NOV 26 2005 .DISCUSSION... ALREADY SEEING SOME UPGLIDE VIRGA OVER SERN MS WITH A FEW SHRA LIKELY REACHING THE SURFACE IN THE KHBG-COLUMBIA AREAS. LATEST RUC/NAM POINTING TOWARD A RAMPING UP OF THE NET ISENTROPIC OMEGA OVER SERN MS IN THE 295-305K LAYERS BY MIDDAY AND THEN OVER ENTIRE SRN HALF OF CWFA BY MID AFTERNOON. HAVE DECIDED TO RAISE POPS FOR THE INITIAL LIGHT RAINS AT LOCATIONS S OF I-20 FOR THIS AFTERNOON. REST OF FORECAST APPEARS ON TRACK FOR NOW WITH FIRST LOW LEVEL JET MAX OF 50KT AT 850MB AND MOISTURE TRANSPORT MAXIMUM COINCIDING NICELY WITH A 250MB DIVERGENT MAXIMUM LATE TONIGHT FOR THE INITIAL BURST OF RAIN/CONVECTION. STILL EXPECT MANY LOCATIONS TO PICK UP 0.5-1.0" OF RAIN. && .AVIATION... TAFS THIS MORNING INTO THIS AFTERNOON WILL REFLECT INCREASING MOISTURE AT ALL LEVELS. EXPECT FLIGHT CATEGORIES TO REMAIN VFR...BUT CLOUD BASES WILL BE GRADUALLY LOWERING TO 4-6K FEET AS AN UPPER DISTURBANCE CURRENTLY OVER TEXAS HEADS THIS WAY. RATHER EXPANSIVE RAIN SHIELD IS EXPECTED BY TONIGHT...WITH BEST COVERAGE OF THUNDERSTORMS ANTICIPATED AT JAN...MEI...HBG. LOOK FOR WIDESPREAD MVFR THIS EVENING AND IFR LATE NIGHT IN BOTH CEILING AND VISIBILITY. CONDITIONS WILL IMPROVE FROM WEST TO EAST DURING THE LATE MORNING HOURS SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 69 61 76 59 / 52 100 20 61 MERIDIAN 69 58 73 63 / 52 100 70 39 VICKSBURG 70 59 80 58 / 72 100 10 70 HATTIESBURG 73 61 77 64 / 72 100 50 26 NATCHEZ 71 62 79 60 / 82 100 10 56 GREENVILLE 67 58 77 56 / 72 100 10 82 GREENWOOD 66 58 75 57 / 42 100 20 79 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 40 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 920 PM EST SAT NOV 26 2005 .SHORT TERM (OVERNIGHT)... RIDGE OF HIGH PRESSURE WILL LINGER OVER THE COASTAL PLAIN DURING THE OVERNIGHT WHILE THE OFFSHORE TROUGH EVOLVES AND SHIFTS TOWARD THE COAST. MID AND HIGH CLOUDINESS WILL INCREASE FROM THE SOUTHWEST AND LOW-LEVEL MOISTURE WILL INCREASE FROM OFF THE ATLANTIC IN RESPONSE TO THE VIGOROUS SHORT WAVE PROGRESSING ALONG THE GULF COAST. CURRENTLY...RADAR MOSAIC DEPICTS INITIAL SHOWER ACTIVITY MOVING ONTO THE GA COAST. ISENTROPIC LIFT ALONG THE 295K SURFACE WILL INCREASE DURING THE OVERNIGHT. COULD SEE SOME SHOWERS DEVELOP ALONG THE COASTAL TROUGH AND SPREAD ONSHORE TOWARD DAY BREAK. AS A RESULT PLAN TO ADD A SMALL POP FOR THE COASTAL ZONES FOR VERY LATE IN THE 1ST PERIOD. AGREE WITH THE LATEST GUIDANCE THAT THE BEST LIFT AND MOISTURE TRANSPORT WILL OCCUR AFTER 12Z TOMORROW. CURRENT TEMPERATURE READINGS ARE ALREADY AT OR NEARING FORECAST MINS. GIVEN THE INCREASING CLOUD COVER WILL ONLY DROP TEMPERATURES BY A CATEGORY. && .AVIATION... PESKY AVIATION FORECAST FOR THE NEXT 24 HOURS. MVFR CEILING OCCASIONALLY MOVING ONSHORE (MYR 1500 FT CEILING) PROBABLY FOR THE NEXT FEW HOURS...THEN HOPEFULLY VFR UNTIL MORNING WHEN ISENTROPIC LIFT PRODUCES STRATIFORM PRECIPITATION STARTING AROUND 14-15Z. PRECIP SHOULD BE LIGHT ENOUGH TO KEEP VISIBILITIES MAINLY VFR... HOWEVER CEILINGS SHOULD LOWER TO MVFR...BASED ON BOTH THE GFS AND ETA. A WEAK WEDGE SITUATION IS POSSIBLE...PARTICULARLY FOR FLO. CEILINGS THERE COULD FALL TO IFR...HOWEVER CONFIDENCE IS NOT HIGH AT THIS TIME SO WILL LEAVE ALL TERMINALS IN THE MVFR RANGE SUNDAY. && .MARINE... BASED ON A LOOK AT THE LATEST ETA AND RUC...IT NOW LOOKS AS THOUGH THE WIND SHIFT TO E-SE WILL OCCUR EARLY SUNDAY AS THE COASTAL TROUGH MOVES THROUGH THE AREA. FOR THE BALANCE OF TONIGHT...EXPECT NE WINDS OF 10 TO 15 KT WITH SEAS OF 3 TO 4 FT. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY SURF CITY TO LITTLE RIVER INLET SUNDAY EVENING THROUGH WEDNESDAY AFTERNOON. && $$ SHORT TERM...PFAFF AVIATION...DL MARINE...RAN nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 806 PM EST SAT NOV 26 2005 .SHORT TERM (REST OF TONIGHT)... CIRRUS MOVING INTO FORECAST AREA BUT THINNING AS IT PUSHES INTO THE UPPER RIDGE. OVERNIGHT THE RIDGE MOVES EAST AND EXPECT AN INCREASE IN OPAQUE CIRRUS LATE...BUT OVERALL THE REST OF THE NIGHT SHOULD BE PARTLY CLOUDY ON AVERAGE. 18Z GFS SEEMS TO BE VERIFYING BEST WITH AREA OF LESSER ENHANCED CLOUDS SHOWING UP AS A RELATIVE MIN OF RH ON UPPER-LEVEL RH PROG AND THIS RELATIVE MINIMUM IS FORECAST BY THAT MODEL TO PUSH INTO CENTRAL NORTH CAROLINA LATE. AGAIN...PARTLY CLOUDY THE RULE OVERNIGHT...ALTHOUGH SOME AREAS SHOULD BECOME MOSTLY CLOUDY LATE PARTICULARLY WEST AND FAR SOUTHERN ZONES. BROAD SPECTRUM OF TEMPERATURES OVER CENTRAL NORTH CAROLINA WITH COLDEST READINGS GENERALLY NORTH AND NORTHEAST OF THE TRIANGLE WHERE OBSERVATIONS AND MSAS SHOW DEW POINTS BEING THE LOWEST. HAVE LOWERED TEMPERATURES MOST ZONES FOR THE OVERNIGHT HOURS...ESPECIALLY TOWARD THE NORTHEAST WHERE READINGS DURING MID EVENING WERE CREEPING CLOSE TO FORECAST MINS. ONSET OF CIRRUS AND SLOWLY INCREASING DEW POINTS SHOULD KEEP TEMPERATURES FROM FALLING TOO FAR TOO FAST...BUT HAD TO BREAK OUT LEE AND JOHNSTON COUNTIES BECAUSE OF LOCAL OBSERVATIONS SHOWING COOL READINGS. DEW POINTS THERE ALREADY APPROACHING 30 OR BETTER AND DROP SHOULD BE SLOW FOR THE REST OF THE NIGHT. GRIDDED AND WORDED FORECAST UPDATES ISSUED. THANKS TO GSP AND AKQ FOR EVENING COORDINATION. && .PREVIOUS DISCUSSION... (ISSUED 246 PM EST SAT NOV 26 2005) SHORT TERM (TONIGHT THROUGH TUESDAY)... 12Z RAOB ANALYSIS SHOWED GOOD MOISTURE COMING NORTH AT 850MB OUT OF THE WESTERN GULF AHEAD OF THE UPPER TROUGH OVER THE SOUTHERN PLAINS. SUBTROPICAL JET EXISTED FROM THE SOUTHERN PLAINS INTO THE CAROLINAS WITH GOOD DIFFLUENCE OVER THE WESTERN GULF ON WATER VAPOR IMAGERY. HIGH CLOUDS HAVE DEVELOPED AND THICKENED DURING THE AFTERNOON PARTICULARLY OVER SOUTHERN ZONES...ALTHOUGH VISIBLE AND IR IMAGES SHOW CONSIDERABLE THINNING OFF TOWARD THE WEST. THE RUC HIGH-LEVEL RH FIELDS SUGGEST CIRRUS SHOULD DIMINISH SOME THIS EVENING BEFORE THE NAM AND GFS SPREAD HIGH AND SOME MID-LEVEL CLOUDS BACK IN OVERNIGHT. UPPER RIDGE MOVES THROUGH CENTRAL NORTH CAROLINA EARLY SUNDAY WITH GOOD DIFFLUENCE IN ITS WAKE. BOTH THE NAM AND THE GFS SUGGEST INCREASING LIFT AND MOISTURE BY 18Z SUNDAY WITH SHORTWAVES AT 500MB AND 700MB MOVING ACROSS THE AREA SUNDAY AFTERNOON. NIL LOW-LEVEL CONVERGENCE SO ALL LIFT IS ISENTROPIC...AND THERE IS SOME CONCERN THAT JET DYNAMICS FROM FLORIDA ACROSS GEORGIA WILL RESULT IN MORE PRECIPITATION THERE VERSUS AREAS FARTHER NORTH SUNDAY AFTERNOON. WILL LIMIT POPS TO HIGH CHANCE FOR NOW...ALTHOUGH ANTICIPATE AT LEAST AREAS OF VERY LIGHT RAIN SUNDAY AFTERNOON AS MID-LEVELS MOISTEN WITH THE ISENTROPIC LIFT. WITH INCREASING MOISTURE AND SURFACE RIDGING REMAINING INTACT WARMING SHOULD BE LIMITED SUNDAY AND HAVE LOWERED MAXES A CATEGORY OR TWO. MODEL SOUNDINGS ALSO SUPPORT THIS WITH STRONG LOW-LEVEL INVERSION IN PLACE. DIFFICULT PART OF THE FORECAST IS LATER SUNDAY NIGHT THROUGH MONDAY NIGHT...DUE TO DIFFERENCES IN THE GFS VERSUS THE NAM. THE LATTER IS MUCH DRIER PARTICULARLY TOWARD THE COASTAL PLAIN DUE TO ITS HIGHER AMPLITUDE RIDGE LOCATED CLOSER TO THE ATLANTIC COAST. AS A RESULT...SUBSIDENCE IS HIGHER ON THE NAM AND DEEPER MOISTURE REMAINS SHUNTED WELL WEST...EVEN TO A LARGE DEGREE WEST OF THE TRIAD. BOTH THE NAM AND THE GFS FORECAST WEAK UVV PARTICULARLY IN WESTERN ZONES MONDAY...AND PLAN TO DEFER SLIGHTLY TO THE GFS DUE TO THE STRENGTH OF THE UPPER TROUGH OVER THE SOUTHERN PLAINS AND THE AMOUNT OF MOISTURE MOVING NORTH ON THE LATEST RAOB ANALYSIS OVER THE GULF. WITH EXACT RIDGE POSITION UNCERTAIN...PRUDENT TO CONTINUE CHANCE POPS WEST TO SLIGHT CHANCE EAST THOUGH FEEL AT THIS POINT PERIODS OF PRECIPITATION SHOULD BE LIMITED WITH AMOUNTS LIGHT. GFS HAS TRENDED SLOWER FROM ITS 00Z AND EVEN 06Z RUNS WITH THE EASTWARD PROGRESSION OF THE SURFACE FRONT TUESDAY AND TUESDAY NIGHT...IN PART COURTESY OF WAVES ALONG THE FRONT AND ITS POSITIVE TILT IN THE SOUTHWEST FLOW ALOFT. THIS COULD RESULT IN PERIODS OF MODERATE RAINFALL ALONG THE FRONT WITH GOOD LIFT FORECAST BY BOTH THE NAM AND THE GFS. JET SUPPORT AT 300MB AND 500MB REMAINS BEST WEST AND NORTH OF THE FORECAST AREA...BUT LOW-LEVEL WIND FIELDS ARE STRONG...40KTS OR GREATER ABOVE 925MB. INSTABILITY SHOULD BE LIMITED TUESDAY DUE TO CLOUDS...HOWEVER...MEAGER BREAKS IN WARM AND MOIST AIR MASS COULD RESULT IN MARGINAL INSTABILITY...ENOUGH FOR THUNDER. MODEL SOUNDINGS ARE NOT IMPRESSIVE REGARDING INSTABILITY... AND LIFTED INDICES BOTH FROM THE NAM AND THE GFS EEK EVER SO SLIGHTLY BELOW ZERO TUESDAY AFTERNOON WITH CAPE FORECAST BETWEEN 100 AND 500J/KG. HAVE DECIDED TO RAISE POPS TUESDAY GIVEN CONSENSUS OF FRONTAL LOCATION FROM THE NAM AND GFS...WITH HIGHEST POPS WEST. LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)... MOIST...SOUTHERLY FLOW AND DECENT LIFT ALONG AND AHEAD OF THE FRONT...ALONG WITH THE SURFACE WAVES...RESULT IN GOOD CHANCES FOR SHOWERS CONTINUING FOR A LARGE PART OF TUESDAY NIGHT WITH THE HIGHEST POPS TOWARD THE I-95 CORRIDOR. WILL LIMIT THUNDER CHANCES FOR THE NIGHTTIME HOURS TUESDAY CENTRAL AND EAST IMMEDIATELY ALONG THE FRONT. CONSENSUS OF GUIDANCE...AND EVEN THE SLOWER GFS...HAS THE COLD FRONT EAST OF CENTRAL NORTH CAROLINA BY 12Z WEDNESDAY AND ANTICIPATE DRY CONDITIONS BY SUNRISE WEDNESDAY WITH DIMINISHING CLOUDS WEDNESDAY MORNING. SUBSIDENCE WILL BE THE RULE FOR THE REST OF THE WEEK AFTER TUESDAY NIGHT. SURFACE RIDGING WILL PREVAIL SOUTH ACROSS THE EASTERN GULF OF MEXICO...AND THOUGH ANOTHER COLD FRONT SHOULD PUSH ACROSS THE STATE LATE THURSDAY INTO FRIDAY AS ANOTHER UPPER TROUGH MOVES THROUGH...SURFACE MOISTURE SHOULD BE LIMITED AND THE GFS KEEPS MOST OF THE ENERGY NORTH OF THE STATE. ALTHOUGH THE DGEX IS MORE AMPLIFIED WITH THE UPPER TROUGH AND FORECASTS DECENT MID-LEVEL VORTICITY TO MOVE OVER CENTRAL NORTH CAROLINA FRIDAY WITH SLIGHTLY MORE MOISTURE...ITS QPF REMAINS DRY. ENSEMBLE MOS POPS ARE ALMOST ALL BELOW CLIMATOLOGY SO WILL MAINTAIN THE DRY FORECAST FOR THE BULK OF THE LONG-TERM PERIOD WITH TEMPERATURES WITHIN A FEW DEGREES OF SEASONAL NORMS. AVIATION... THIN BKN CIRRUS SPREADING OVER CENTRAL NC THIS AFTERNOON WILL REMAIN AROUND 25KFT THROUGH MIDNIGHT. MODEL RUNS THIS AFTERNOON HAVE BECOME MORE AGGRESSIVE WITH MOISTURE INCREASING IN THE LOWER LEVELS SUNDAY MORNING. THE NAM IS FASTER AT INCREASING LOW CLOUDS EARLY SUNDAY MORNING AND THIS FORECAST LEANS MORE TOWARDS THE SLOWER GFS. BOTH MODELS SHOW STRONG OVERRUNNING SETTING UP BY MID TO LATE MORNING WITH A LOW LEVEL JET OF 30KT. EXPECT A RAPID INCREASE OF MID AND LOW CLOUDS SUNDAY MORNING. MVFR CONDITIONS SHOULD DEVELOP FROM SUNRISE THROUGH MID MORNING. CEILINGS WILL CONTINUE TO LOWER THROUGH THE LATE MORNING HOURS APPROACHING VFR CONDITIONS BY AFTERNOON. OVERRUNNING LIFT WILL ALSO GENERATE SOME PRECIP FROM LATE MORNING INTO THE AFTERNOON RESULTING IN LIMITED VISIBILITIES FOR EARLY AND MID AFTERNOON. EXPECT MVFR TO IFR CONDITIONS TO PERSIST THROUGH MUCH OF SUNDAY AFTERNOON. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 246 PM EST SAT NOV 26 2005 .SHORT TERM (TONIGHT THROUGH TUESDAY)... 12Z RAOB ANALYSIS SHOWED GOOD MOISTURE COMING NORTH AT 850MB OUT OF THE WESTERN GULF AHEAD OF THE UPPER TROUGH OVER THE SOUTHERN PLAINS. SUBTROPICAL JET EXISTED FROM THE SOUTHERN PLAINS INTO THE CAROLINAS WITH GOOD DIFFLUENCE OVER THE WESTERN GULF ON WATER VAPOR IMAGERY. HIGH CLOUDS HAVE DEVELOPED AND THICKENED DURING THE AFTERNOON PARTICULARLY OVER SOUTHERN ZONES...ALTHOUGH VISIBLE AND IR IMAGES SHOW CONSIDERABLE THINNING OFF TOWARD THE WEST. THE RUC HIGH-LEVEL RH FIELDS SUGGEST CIRRUS SHOULD DIMINISH SOME THIS EVENING BEFORE THE NAM AND GFS SPREAD HIGH AND SOME MID-LEVEL CLOUDS BACK IN OVERNIGHT. UPPER RIDGE MOVES THROUGH CENTRAL NORTH CAROLINA EARLY SUNDAY WITH GOOD DIFFLUENCE IN ITS WAKE. BOTH THE NAM AND THE GFS SUGGEST INCREASING LIFT AND MOISTURE BY 18Z SUNDAY WITH SHORTWAVES AT 500MB AND 700MB MOVING ACROSS THE AREA SUNDAY AFTERNOON. NIL LOW-LEVEL CONVERGENCE SO ALL LIFT IS ISENTROPIC...AND THERE IS SOME CONCERN THAT JET DYNAMICS FROM FLORIDA ACROSS GEORGIA WILL RESULT IN MORE PRECIPITATION THERE VERSUS AREAS FARTHER NORTH SUNDAY AFTERNOON. WILL LIMIT POPS TO HIGH CHANCE FOR NOW...ALTHOUGH ANTICIPATE AT LEAST AREAS OF VERY LIGHT RAIN SUNDAY AFTERNOON AS MID-LEVELS MOISTEN WITH THE ISENTROPIC LIFT. WITH INCREASING MOISTURE AND SURFACE RIDGING REMAINING INTACT WARMING SHOULD BE LIMITED SUNDAY AND HAVE LOWERED MAXES A CATEGORY OR TWO. MODEL SOUNDINGS ALSO SUPPORT THIS WITH STRONG LOW-LEVEL INVERSION IN PLACE. DIFFICULT PART OF THE FORECAST IS LATER SUNDAY NIGHT THROUGH MONDAY NIGHT...DUE TO DIFFERENCES IN THE GFS VERSUS THE NAM. THE LATTER IS MUCH DRIER PARTICULARLY TOWARD THE COASTAL PLAIN DUE TO ITS HIGHER AMPLITUDE RIDGE LOCATED CLOSER TO THE ATLANTIC COAST. AS A RESULT...SUBSIDENCE IS HIGHER ON THE NAM AND DEEPER MOISTURE REMAINS SHUNTED WELL WEST...EVEN TO A LARGE DEGREE WEST OF THE TRIAD. BOTH THE NAM AND THE GFS FORECAST WEAK UVV PARTICULARLY IN WESTERN ZONES MONDAY...AND PLAN TO DEFER SLIGHTLY TO THE GFS DUE TO THE STRENGTH OF THE UPPER TROUGH OVER THE SOUTHERN PLAINS AND THE AMOUNT OF MOISTURE MOVING NORTH ON THE LATEST RAOB ANALYSIS OVER THE GULF. WITH EXACT RIDGE POSITION UNCERTAIN...PRUDENT TO CONTINUE CHANCE POPS WEST TO SLIGHT CHANCE EAST THOUGH FEEL AT THIS POINT PERIODS OF PRECIPITATION SHOULD BE LIMITED WITH AMOUNTS LIGHT. GFS HAS TRENDED SLOWER FROM ITS 00Z AND EVEN 06Z RUNS WITH THE EASTWARD PROGRESSION OF THE SURFACE FRONT TUESDAY AND TUESDAY NIGHT...IN PART COURTESY OF WAVES ALONG THE FRONT AND ITS POSITIVE TILT IN THE SOUTHWEST FLOW ALOFT. THIS COULD RESULT IN PERIODS OF MODERATE RAINFALL ALONG THE FRONT WITH GOOD LIFT FORECAST BY BOTH THE NAM AND THE GFS. JET SUPPORT AT 300MB AND 500MB REMAINS BEST WEST AND NORTH OF THE FORECAST AREA...BUT LOW-LEVEL WIND FIELDS ARE STRONG...40KTS OR GREATER ABOVE 925MB. INSTABILITY SHOULD BE LIMITED TUESDAY DUE TO CLOUDS...HOWEVER...MEAGER BREAKS IN WARM AND MOIST AIR MASS COULD RESULT IN MARGINAL INSTABILITY...ENOUGH FOR THUNDER. MODEL SOUNDINGS ARE NOT IMPRESSIVE REGARDING INSTABILITY... AND LIFTED INDICES BOTH FROM THE NAM AND THE GFS EEK EVER SO SLIGHTLY BELOW ZERO TUESDAY AFTERNOON WITH CAPE FORECAST BETWEEN 100 AND 500J/KG. HAVE DECIDED TO RAISE POPS TUESDAY GIVEN CONSENSUS OF FRONTAL LOCATION FROM THE NAM AND GFS...WITH HIGHEST POPS WEST. && .LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)... MOIST...SOUTHERLY FLOW AND DECENT LIFT ALONG AND AHEAD OF THE FRONT...ALONG WITH THE SURFACE WAVES...RESULT IN GOOD CHANCES FOR SHOWERS CONTINUING FOR A LARGE PART OF TUESDAY NIGHT WITH THE HIGHEST POPS TOWARD THE I-95 CORRIDOR. WILL LIMIT THUNDER CHANCES FOR THE NIGHTTIME HOURS TUESDAY CENTRAL AND EAST IMMEDIATELY ALONG THE FRONT. CONSENSUS OF GUIDANCE...AND EVEN THE SLOWER GFS...HAS THE COLD FRONT EAST OF CENTRAL NORTH CAROLINA BY 12Z WEDNESDAY AND ANTICIPATE DRY CONDITIONS BY SUNRISE WEDNESDAY WITH DIMINISHING CLOUDS WEDNESDAY MORNING. SUBSIDENCE WILL BE THE RULE FOR THE REST OF THE WEEK AFTER TUESDAY NIGHT. SURFACE RIDGING WILL PREVAIL SOUTH ACROSS THE EASTERN GULF OF MEXICO...AND THOUGH ANOTHER COLD FRONT SHOULD PUSH ACROSS THE STATE LATE THURSDAY INTO FRIDAY AS ANOTHER UPPER TROUGH MOVES THROUGH...SURFACE MOISTURE SHOULD BE LIMITED AND THE GFS KEEPS MOST OF THE ENERGY NORTH OF THE STATE. ALTHOUGH THE DGEX IS MORE AMPLIFIED WITH THE UPPER TROUGH AND FORECASTS DECENT MID-LEVEL VORTICITY TO MOVE OVER CENTRAL NORTH CAROLINA FRIDAY WITH SLIGHTLY MORE MOISTURE...ITS QPF REMAINS DRY. ENSEMBLE MOS POPS ARE ALMOST ALL BELOW CLIMATOLOGY SO WILL MAINTAIN THE DRY FORECAST FOR THE BULK OF THE LONG-TERM PERIOD WITH TEMPERATURES WITHIN A FEW DEGREES OF SEASONAL NORMS. && .AVIATION... THIN BKN CIRRUS SPREADING OVER CENTRAL NC THIS AFTERNOON WILL REMAIN AROUND 25KFT THROUGH MIDNIGHT. MODEL RUNS THIS AFTERNOON HAVE BECOME MORE AGGRESSIVE WITH MOISTURE INCREASING IN THE LOWER LEVELS SUNDAY MORNING. THE NAM IS FASTER AT INCREASING LOW CLOUDS EARLY SUNDAY MORNING AND THIS FORECAST LEANS MORE TOWARDS THE SLOWER GFS. BOTH MODELS SHOW STRONG OVERRUNNING SETTING UP BY MID TO LATE MORNING WITH A LOW LEVEL JET OF 30KT. EXPECT A RAPID INCREASE OF MID AND LOW CLOUDS SUNDAY MORNING. MVFR CONDITIONS SHOULD DEVELOP FROM SUNRISE THROUGH MID MORNING. CEILINGS WILL CONTINUE TO LOWER THROUGH THE LATE MORNING HOURS APPROACHING VFR CONDITIONS BY AFTERNOON. OVERRUNNING LIFT WILL ALSO GENERATE SOME PRECIP FROM LATE MORNING INTO THE AFTERNOON RESULTING IN LIMITED VISIBILITIES FOR EARLY AND MID AFTERNOON. EXPECT MVFR TO IFR CONDITIONS TO PERSIST THROUGH MUCH OF SUNDAY AFTERNOON. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJF LONG TERM...DJF AVIATION...JO nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CLEVELAND OHIO 1035 AM EST SAT NOV 26 2005 .SHORT TERM (THIS AFTERNOON)... UPDATED TO REMOVE MORNING PORTION. ALSO KEPT MENTION OF SPRINKLES OR FLURRIES FOR THE AFTERNOON. && .SHORT TERM (TODAY) UPDATE... PCPN MOVING OUT NORTH CENTRAL OH...UPDATING JUST TO CLARIFY THE WORDING. MODELS IN AGREEMENT. && .AVIATION(12Z-12Z)... WARM FRONT ACROSS NORTHERN OHIO WILL MOVE SLOWLY NORTH TODAY AND THEN MOVE NORTH OF THE LAKE TONIGHT. PCPN ASSOCIATED WITH WARM FRONT DECREASING RAPIDLY AS PER 88D. MODELS HAD A VERY GOOD HANDLE ON THIS. SATELLITE SHOWING A LARGE AREA OF DECREASING CLOUDS MOVING INTO NORTHWEST INDIANA. IT SEEMS TO BE MOVING EAST. THE ETA...GFS AND RUC ALL INDICATE THAT THE LOW LEVEL MOISTURE REMAINS IN PLACE THROUGH 12Z SUNDAY...IN FACT THE CEILING HEIGHT WILL LOWER DURING THE UPCOMING NIGHT. THE MODELS DO INDICATE SOME UVV TODAY...THIS MAY KEEP SOME FLURRIES OR SPRINKLES GOING...ATTM WILL NOT MENTION THAT IN THE TAFS...EXCEPT FOR SOME LINGERING PCPN FOR ERI AND YNG UNTIL 14Z. WITH THE UVV AND THE LASTEST SATELLITE TRYING TO SHOW THE BACK EDGE NOT MAKING AS MUCH ADVANCEMENT WILL KEEP MOST LOCATIONS BROKEN THRU THE TAF...NONE THE LESS IT WILL BE VFR CEILING AND VSBY. && .SHORT TERM(TODAY THRU SUN)... BAND OF WAA SN ACRS NRN OH ON TRACK AS EXPECTED. BASED ON MSTR AND LIFT SHUD END WITH ABT TRACE TO 3 IN TOTAL MOST PLACES THIS MORN WITH HIER AMTS GNLY IN NERN CO'S. WL BASE POPS ON CURRENT RAD PIX AT ZONE TIME. STG WAA AND LIFT...WUD NOT BE SUPRISED IF LGT SN OR FLURRIES LINGER WELL INTO AFTN IN THE NE WITH MAYBE SOME SPRINKLES FURTHER SW. WAA RAINS SPREAD W TO E INTO AREA LATER TNGT. CURRENT GRIDDS HV HANDLE ON THIS SO SHUD ONLY NEED A FEW MINOR CHGS. RA CONTS W ON SUN WITH TAPERING TO CHC POPS E. && .LONG TERM (SUNDAY NITE THRU FRI)... BIG CHANGES ARE EXPECTED IN THE LONG TERM WITH A LARGE WARM UP EARLY IN THE WEEK AND A COOL DOWN WITH MORE LAKE EFFECT SNOW POSSIBLE BY THE END OF THE WORK WEEK. THE GFS AND ECMWF ARE FAIRLY SIMILAR WITH THE EVOLUTION OF THE UPPER PATTERN NEXT WEEK. TEMPERATURES MAY REACH INTO THE 60S MONDAY AND BE FOLLOWED BY A VERY MILD NIGHT BEFORE FRONTAL PASSAGE MONDAY NIGHT. WE WILL NEED TO MONITOR THE RETURN OF DEEP MOISTURE AND ASSESS THE POTENTIAL FOR SEVERE CONVECTION GIVEN THE STRONG WIND FIELDS. LAKE EFFECT SNOW MAY DEVELOP WED AND PERSIST INTO THE SNOW BELT INTO FRI. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. && SHORT TERM...LW/ADAMS LONG TERM...REL AVIATION...KIELTYKA $$ oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CLEVELAND OHIO 726 AM EST SAT NOV 26 2005 .SHORT TERM (TODAY) UPDATE... PCPN MOVING OUT NORTH CENTRAL OH...UPDATING JUST TO CLARIFY THE WORDING. MODELS IN AGREEMENT. && .AVIATION(12Z-12Z)... WARM FRONT ACROSS NORTHERN OHIO WILL MOVE SLOWLY NORTH TODAY AND THEN MOVE NORTH OF THE LAKE TONIGHT. PCPN ASSOCIATED WITH WARM FRONT DECREASING RAPIDLY AS PER 88D. MODELS HAD A VERY GOOD HANDLE ON THIS. SATELLITE SHOWING A LARGE AREA OF DECREASING CLOUDS MOVING INTO NORTHWEST INDIANA. IT SEEMS TO BE MOVING EAST. THE ETA...GFS AND RUC ALL INDICATE THAT THE LOW LEVEL MOISTURE REMAINS IN PLACE THROUGH 12Z SUNDAY...IN FACT THE CEILING HEIGHT WILL LOWER DURING THE UPCOMING NIGHT. THE MODELS DO INDICATE SOME UVV TODAY...THIS MAY KEEP SOME FLURRIES OR SPRINKLES GOING...ATTM WILL NOT MENTION THAT IN THE TAFS...EXCEPT FOR SOME LINGERING PCPN FOR ERI AND YNG UNTIL 14Z. WITH THE UVV AND THE LASTEST SATELLITE TRYING TO SHOW THE BACK EDGE NOT MAKING AS MUCH ADVANCEMENT WILL KEEP MOST LOCATIONS BROKEN THRU THE TAF...NONE THE LESS IT WILL BE VFR CEILING AND VSBY. && .SHORT TERM(TODAY THRU SUN)... BAND OF WAA SN ACRS NRN OH ON TRACK AS EXPECTED. BASED ON MSTR AND LIFT SHUD END WITH ABT TRACE TO 3 IN TOTAL MOST PLACES THIS MORN WITH HIER AMTS GNLY IN NERN CO'S. WL BASE POPS ON CURRENT RAD PIX AT ZONE TIME. STG WAA AND LIFT...WUD NOT BE SUPRISED IF LGT SN OR FLURRIES LINGER WELL INTO AFTN IN THE NE WITH MAYBE SOME SPRINKLES FURTHER SW. WAA RAINS SPREAD W TO E INTO AREA LATER TNGT. CURRENT GRIDDS HV HANDLE ON THIS SO SHUD ONLY NEED A FEW MINOR CHGS. RA CONTS W ON SUN WITH TAPERING TO CHC POPS E. && .LONG TERM (SUNDAY NITE THRU FRI)... BIG CHANGES ARE EXPECTED IN THE LONG TERM WITH A LARGE WARM UP EARLY IN THE WEEK AND A COOL DOWN WITH MORE LAKE EFFECT SNOW POSSIBLE BY THE END OF THE WORK WEEK. THE GFS AND ECMWF ARE FAIRLY SIMILAR WITH THE EVOLUTION OF THE UPPER PATTERN NEXT WEEK. TEMPERATURES MAY REACH INTO THE 60S MONDAY AND BE FOLLOWED BY A VERY MILD NIGHT BEFORE FRONTAL PASSAGE MONDAY NIGHT. WE WILL NEED TO MONITOR THE RETURN OF DEEP MOISTURE AND ASSESS THE POTENTIAL FOR SEVERE CONVECTION GIVEN THE STRONG WIND FIELDS. LAKE EFFECT SNOW MAY DEVELOP WED AND PERSIST INTO THE SNOW BELT INTO FRI. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. && SHORT TERM...ADAMS LONG TERM...REL AVIATION...KIELTYKA $$ oh AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE CLEVELAND OHIO 642 AM EST SAT NOV 26 2005 .AVIATION(12Z-12Z)... WARM FRONT ACROSS NORTHERN OHIO WILL MOVE SLOWLY NORTH TODAY AND THEN MOVE NORTH OF THE LAKE TONIGHT. PCPN ASSOCIATED WITH WARM FRONT DECREASING RAPIDLY AS PER 88D. MODELS HAD A VERY GOOD HANDLE ON THIS. SATELLITE SHOWING A LARGE AREA OF DECREASING CLOUDS MOVING INTO NORTHWEST INDIANA. IT SEEMS TO BE MOVING EAST. THE ETA...GFS AND RUC ALL INDICATE THAT THE LOW LEVEL MOISTURE REMAINS IN PLACE THROUGH 12Z SUNDAY...IN FACT THE CEILING HEIGHT WILL LOWER DURING THE UPCOMING NIGHT. THE MODELS DO INDICATE SOME UVV TODAY...THIS MAY KEEP SOME FLURRIES OR SPRINKLES GOING...ATTM WILL NOT MENTION THAT IN THE TAFS...EXCEPT FOR SOME LINGERING PCPN FOR ERI AND YNG UNTIL 14Z. WITH THE UVV AND THE LASTEST SATELLITE TRYING TO SHOW THE BACK EDGE NOT MAKING AS MUCH ADVANCEMENT WILL KEEP MOST LOCATIONS BROKEN THRU THE TAF...NONE THE LESS IT WILL BE VFR CEILING AND VSBY. && .SHORT TERM(TODAY THRU SUN)... BAND OF WAA SN ACRS NRN OH ON TRACK AS EXPECTED. BASED ON MSTR AND LIFT SHUD END WITH ABT TRACE TO 3 IN TOTAL MOST PLACES THIS MORN WITH HIER AMTS GNLY IN NERN CO'S. WL BASE POPS ON CURRENT RAD PIX AT ZONE TIME. STG WAA AND LIFT...WUD NOT BE SUPRISED IF LGT SN OR FLURRIES LINGER WELL INTO AFTN IN THE NE WITH MAYBE SOME SPRINKLES FURTHER SW. WAA RAINS SPREAD W TO E INTO AREA LATER TNGT. CURRENT GRIDDS HV HANDLE ON THIS SO SHUD ONLY NEED A FEW MINOR CHGS. RA CONTS W ON SUN WITH TAPERING TO CHC POPS E. && .LONG TERM (SUNDAY NITE THRU FRI)... BIG CHANGES ARE EXPECTED IN THE LONG TERM WITH A LARGE WARM UP EARLY IN THE WEEK AND A COOL DOWN WITH MORE LAKE EFFECT SNOW POSSIBLE BY THE END OF THE WORK WEEK. THE GFS AND ECMWF ARE FAIRLY SIMILAR WITH THE EVOLUTION OF THE UPPER PATTERN NEXT WEEK. TEMPERATURES MAY REACH INTO THE 60S MONDAY AND BE FOLLOWED BY A VERY MILD NIGHT BEFORE FRONTAL PASSAGE MONDAY NIGHT. WE WILL NEED TO MONITOR THE RETURN OF DEEP MOISTURE AND ASSESS THE POTENTIAL FOR SEVERE CONVECTION GIVEN THE STRONG WIND FIELDS. LAKE EFFECT SNOW MAY DEVELOP WED AND PERSIST INTO THE SNOW BELT INTO FRI. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. && SHORT TERM...ADAMS LONG TERM...REL AVIATION...KIELTYKA $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 257 PM CST SAT NOV 26 2005 .DISCUSSION... TWO DAYS AGO WE DETERMINED THAT THE RECENT PERSISTENT LONGWAVE PATTERN WOULD BREAK DOWN...THAT THE MODELS WOULD HAVE A HARD TIME WITH THE TRANSITION...AND THAT THE RESULTING NEW PATTERN WOULD INCLUDE A BROAD AND FAIRLY AMPLIFIED LONGWAVE TROF OVER THE CENTRAL CONUS BY MID-LATE NEXT WEEK. TWO OUT OF THREE AIN'T BAD. WE - AND THE MODELS - BUSTED ON THE NEW PATTERN WHICH NOW LOOKS MORE LIKE A HIGH LATITUDE BLOCK SETTING UP OVER THE NE PACIFIC. THIS LEADS TO BIGGER HEIGHT FALLS DOWNSTREAM OVER WESTERN NOAM....WHICH IN TURN AMPLIFIES A DOWNSTREAM RIDGE OVER THE CENTRAL CONUS BY LATE NEXT WEEK. SO MUCH FOR THE COOL AND WETTER /POSSIBLY WINTERY/ REGIME WE EXPECTED A COUPLE DAYS AGO. AT LEAST THE CURRENT SUITE OF MODEL RUNS LOOKS MODERATELY CONSISTENT IN SETTING UP THE CENTRAL CONUS RIDGE BY NEXT FRI...BUT THEY WELL COULD SWING TOWARD AN ENTIRELY DIFFERENT SOLUTION BY THIS TIME TOMORROW. SINCE UNCERTAINTY IS STILL QUITE A BIT HIGHER THAN USUAL IN THE MEDIUM RANGE...WE HAVE OPTED TO SIMPLY FOLLOW THE LEAD OF HPC ON DAY 3-7 HIGHS/LOWS/POPS IN THIS PACKAGE. RESULT IS A DRY FORECAST...WHICH ALSO FITS WELL WITH RECENT TRENDS LOCALLY...AND TEMPS THAT ARE CLOSER TO CLIMATOLOGY THAN WHAT WE HAD OUT THERE EARLIER IN THE WEEK. IN THE SHORT TERM...MAIN CATALYST BEHIND THE PATTERN TRANSITION IS THE POWERHOUSE SYSTEM NOW DIGGING INTO THE CENTRAL/S ROCKIES - COURTESY OF A 200-KT UPPER JET DIVING ACROSS CA. THIS ONE INDEED WILL LEAD TO A TROF OVER THE CENTRAL CONUS EARLY NEXT WEEK...BUT IT IS NOT LIKELY TO LAST THE WEEK. WEAKER SYSTEM NOW BEING EJECTED ACROSS THE LOWER MS VALLEY WILL HAVE LIMITED AFFECT HERE...EXCEPT TO INTERCEPT BETTER LL MOISTURE AND THUS KEEP THE POTENTIAL FOR STRONG/SEVERE CONVECTION IN OUR AREA MINIMAL THRU SUN. HOWEVER... MODIFIED RUC SOUNDINGS THIS AFTERNOON/EVENING YIELD SBCAPES OF 1000-1500 J/KG AND NOT A WHOLE LOT OF CIN OVER W OK. PROBLEMS WILL BE PREVAILING SUBSIDENCE AND A BROAD NOT-WELL-DEFINED DRYLINE AT PRESENT. BUT MAY NEED TO WATCH OUT IF ANYTHING CAN INITIATE BEFORE 23-00Z AS EARLY-EVENING SRH VALUES OFF THE NAM ARE 200-400 M2/S2 /0-1KM/ AND 300-500 /0-3KM/. PRESSURE FALLS WILL KEEP WINDS UP TONIGHT AS THE SFC LOW REVS UP OVER KS. WHAT MOISTURE DOES RETURN WILL LIKELY BRING GULF STRATUS BACK N LATER TONIGHT TO AREAS MAINLY NEAR AND E OF I-35. EXPECT STRONG SW WINDS ON SUN AS SHARPENING DRYLINE PUNCHES E TO THE S OF THE DEEPENING LOW OVER KS. COULD NEED ANOTHER WIND ADVISORY...AND THERE MAY EVEN BE BLOWING DUST...BUT PRECIP CHANCES WILL BE LIMITED IN THE DRY SLOT. BETTER CHANCES WILL BE TO OUR E IN FORM OF STRONG STORMS NEAR/E OF DRYLINE...AND INTO NW/NCENTRAL OK WHERE WRAPAROUND CLOUDS/RAIN MAY BE PULLED DOWN INTO THE SW QUAD OF THE SFC LOW SUN INTO SUN EVENING. WE CURRENTLY THINK PRECIP CHANCES WILL DIMINISH BEFORE ANY PARTS OF N OK GET COLD ENOUGH TO CHANGE OVER SUNDAY NIGHT. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 53 67 35 52 / 10 10 10 0 HOBART OK 49 63 33 54 / 10 10 10 0 WICHITA FALLS TX 54 71 36 59 / 10 10 10 0 GAGE OK 43 53 27 49 / 20 40 20 0 PONCA CITY OK 53 63 35 46 / 20 20 20 10 DURANT OK 57 75 42 60 / 20 10 10 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...RED FLAG WARNING UNTIL 6 PM CST THIS AFTERNOON FOR OKZ004-OKZ005- OKZ006-OKZ007-OKZ008-OKZ009-OKZ010-OKZ011-OKZ012-OKZ013- OKZ014-OKZ015-OKZ016-OKZ017-OKZ018-OKZ019-OKZ020-OKZ021- OKZ022-OKZ023-OKZ024-OKZ025-OKZ027-OKZ033-OKZ034-OKZ035- OKZ036-OKZ037-OKZ038-OKZ039-OKZ044-OKZ045. WIND ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR OKZ004-OKZ005- OKZ006-OKZ009-OKZ010-OKZ011-OKZ014-OKZ015-OKZ016. FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR OKZ023-OKZ024-OKZ025-OKZ026-OKZ027-OKZ028-OKZ029-OKZ030- OKZ031-OKZ032-OKZ033-OKZ034-OKZ035-OKZ036-OKZ037-OKZ038- OKZ039-OKZ040-OKZ041-OKZ042-OKZ043-OKZ044-OKZ045-OKZ046- OKZ047-OKZ048-OKZ050-OKZ051-OKZ052. TX...RED FLAG WARNING UNTIL 6 PM CST THIS AFTERNOON FOR TXZ083-TXZ084- TXZ085-TXZ086-TXZ087-TXZ088-TXZ089-TXZ090. FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR TXZ083-TXZ084-TXZ085-TXZ086-TXZ087-TXZ088-TXZ089-TXZ090. && $$ 22 SHORT TERM 24 LONG TERM ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1130 AM CST SAT NOV 26 2005 .UPDATE...OVERALL JUST MINOR ADJUSTMENTS MADE TO THE AFTERNOON FORECAST. MAINTAINED THE WESTERN EDGE OF RAIN CHANCES ALONG A WICHITA FALLS TO OKC TO STILLWATER LINE...BUT INCREASED POPS TO 50 AND 60 PERCENT FARTHER SOUTH AND EAST BASED ON RADAR TRENDS AND RUC FORECAST. CLOUD COVER HAS HELPED PREVENT ANY THUNDERSTORMS FROM BECOMING SURFACE BASED...SO INSTABILITY IS LIMITED...AND THESE SHOULD NOT CAUSE ANY TROUBLE ASIDE FROM BRIEF HEAVY RAIN AND LIGHTNING. MEANWHILE...AREAS NORTH AND WEST WILL SEE ABUNDANT SUNSHINE EARLY IN THE AFTERNOON. NEW GUIDANCE TEMPERATURES SUGGEST LOWER 70S POSSIBLE. HOWEVER...THERE IS ALREADY EVIDENCE OF LOW CLOUDS DEVELOPING AND EXPANDING IN THESE AREAS...WHICH SHOULD HOLD TEMPS IN CHECK. ONLY TWEAKED THEM UPWARDS A COUPLE DEGREES. && .PREV DISCUSSION... (ISSUED 421 AM CST SAT NOV 26 2005) DISCUSSION... THE LEAD UPPER WAVE OVER SOUTHWEST TEXAS EARLY THIS MORNING WILL MOVE INTO EAST TEXAS BY LATE TODAY. MOST OF THE PRECIPITATION WITH THIS SYSTEM WILL BE ACROSS SOUTHERN AND EASTERN TEXAS ALTHOUGH WE COULD SEE SCATTERED SHOWERS... AND POSSIBLY A FEW T-STORMS... FARTHER NORTH INTO OUR AREA WITH THE BEST CHANCES ACROSS SOUTHEAST OKLAHOMA. SOME MODIFIED GULF MOISTURE HAS BEEN SPREADING NORTH OVERNIGHT AS EVIDENCED BY THE APPEARANCE OF LOW CLOUDS ON SATELLITE. MEANWHILE... A STRONGER SYSTEM MOVING INTO THE SOUTHERN ROCKIES EARLY SUNDAY WILL INITIATE CYCLOGENESIS OVER THE SOUTH CENTRAL PLAINS. AGAIN IT LOOKS LIKE THE BEST PCPN CHANCES ON SUNDAY WILL AGAIN BE OVER OUR SOUTHEAST ZONES AS VEERING WINDS JUST OFF THE DECK SUNDAY MORNING ACROSS THE REMAINDER OF THE AREA WILL RESULT IN A RATHER SHALLOW MOISTURE FIELD. WE LOOK FOR THE DRYLINE TO MOVE EAST INTO CENTRAL OKLAHOMA BY AFTERNOON WITH THE COLD FRONT DROPPING INTO NORTHWEST OKLAHOMA. SURFACE WINDS ARE EXPECTED TO BE FAIRLY STOUT WITH AS THE SURFACE LOW DEVELOPS A RELATIVELY TIGHT PRESSURE GRADIENT. MEANWHILE... COLD TEMPERATURES SPREADING IN ALOFT BY LATE SUNDAY COULD SUPPORT SOME SNOW IN THE NORTHWEST. HOWEVER... ANY PCPN LINGERING IN THAT AREA BY THEN SHOULD BE LIGHT... AND WITH THE LOWER LEVEL THICKNESSES STILL RELATIVELY WARM... WE EXPECT ONLY A LIGHT MIX OF RAIN/WET SNOW. COOLER AIR WILL SPREAD IN BEHIND THE FRONT FOR MONDAY AND TUESDAY... BEFORE TEMPS WARM UP BRIEFLY AROUND MID WEEK... AND THEN COOL AGAIN BY THURSDAY. FIRE WEATHER WILL BE A CONCERN THIS WEEKEND. A HIGH FIRE DANGER IS EXPECTED THIS AFTERNOON OVER THE WESTERN HALF OF THE AREA AS BOTH WINDS AND TEMPS INCREASE. EXTREME CONDITIONS ARE EXPECTED SUNDAY AFTERNOON ALONG AND SOUTH OF INTERSTATE 40... GENERALLY IN THE SECTOR WEST OF THE DRYLINE AND SOUTH OF THE FRONT WHERE WE SHOULD SEE VERY WARM TEMPERATURES... LOW DEWPOINTS AND STRONG WINDS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 68 55 70 37 / 20 20 20 10 HOBART OK 72 50 68 35 / 10 20 20 10 WICHITA FALLS TX 70 54 77 38 / 20 20 20 10 GAGE OK 70 43 57 30 / 10 20 40 30 PONCA CITY OK 69 54 67 37 / 20 20 30 30 DURANT OK 66 59 80 44 / 60 20 30 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR OKZ023-OKZ024-OKZ025-OKZ026-OKZ027-OKZ028-OKZ029-OKZ030- OKZ031-OKZ032-OKZ033-OKZ034-OKZ035-OKZ036-OKZ037-OKZ038- OKZ039-OKZ040-OKZ041-OKZ042-OKZ043-OKZ044-OKZ045-OKZ046- OKZ047-OKZ048-OKZ050-OKZ051-OKZ052. TX...FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR TXZ083-TXZ084-TXZ085-TXZ086-TXZ087-TXZ088-TXZ089-TXZ090. && $$ 22/24 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 415 AM MST SAT NOV 26 2005 .SYNOPSIS...A STRONG COLD FRONT MOVING ACROSS THE AREA TODAY WILL USHER A COLD...MOIST AND UNSTABLE AIRMASS INTO THE REGION. UNSETTLED WEATHER IS EXPECTED TO CONTINUE THROUGH THE FIRST HALF OF THE UPCOMING WEEK. && .DISCUSSION...POWERFUL PACIFIC JET IMPINGING ON PACIFIC COAST THIS MORNING...WITH LEAD SHORTWAVE TROUGH CURRENTLY TRANSLATING ACROSS NORTHERN UT. VORT MAX ASSOCIATED WITH THIS SHORTWAVE CURRENTLY TRANSLATING ACROSS GREAT SALT LAKE DESERT...WITH REGION OF STRONG PVA ALONG WITH ENTRANCE REGION OF JET RESULTING IN UPWARD VERTICAL MOTION AND RESULTANT PRECIPITATION ACROSS MUCH OF NORTHERN UTAH AND FAR SOUTHWEST WYOMING. FAIRLY STRONG 700MB COLD ADVECTION IN PLACE ACROSS NORTHERN UT WITH RUC-ANALYZED 700MB TEMPS CURRENTLY AROUND -6C. JUST UPSTREAM STRONG 500MB COLD ADVECTION CURRENTLY SPREADING INTO NORTHWESTERN UT AND RESULTING IN AN INCREASE IN CONVECTION ACROSS THE GREAT SALT LAKE DESERT...EVIDENCED BY COOLING CLOUD TOPS IN IR IMAGERY. AS SHORTWAVE TROUGH CONTINUES TO TRANSLATE EASTWARD THIS MORNING EXPECT SEVERAL MORE HOURS OF PRECIPITATION ACROSS NORTHERN UT. CONTINUED COLD ADVECTION WILL ALLOW SNOW LEVELS TO FALL TO THE VALLEY FLOORS BY NOONTIME. AS COLD ADVECTION CONTINUES THROUGHOUT THIS AFTERNOON...BOTH ALOFT AND AT THE SURFACE...OCCASIONAL SNOW SHOWERS WILL CONTINUE ACROSS THE NORTHERN HALF OF THE CWA. TWO AREAS OF ENHANCED PRECIPITATION ARE EXPECTED OVERNIGHT. THE FIRST IS ACROSS AREAS SOUTHEAST OF THE GREAT SALT LAKE...WHERE VERY COLD AIR ALOFT /-16 AT 700MB AND -34 AT 500MB/ WILL RESULT IN STEEP LAPSE RATES AND SUPPORT DEVELOPMENT OF HEAVY SNOWBANDS OVER THE GREAT SALT LAKE. NORTHWEST WINDS THROUGHOUT THE 700-500MB LAYER SHOULD STEER THESE BANDS SOUTHEAST INTO AREAS FROM FAR SOUTHERN DAVIS COUNTY THROUGH EASTERN SALT LAKE COUNTY...AND PERHAPS FAR NORTHERN UTAH COUNTY...WHERE WARNING CRITERIA SNOWS CAN BE EXPECTED. AS A RESULT HAVE GONE AHEAD AND ISSUED A HEAVY SNOW WARNING FOR THE WASATCH FRONT. ALTHOUGH HEAVIEST SNOW IS EXPECTED OVERNIGHT...ONSET OF SNOW IN THESE AREAS DURING THE DAYTIME HOURS REQUIRES WARNING TO BEGIN DURING THE DAYTIME PERIOD. SECOND AREA IS ACROSS CENTRAL UTAH WHERE SECONDARY SHORTWAVE TROUGH WILL RESULT IN ENHANCEMENT IN SNOWFALL OVERNIGHT. HAVE GONE WITH A SNOW ADVISORY FOR WEST CENTRAL UTAH...ZONE 15...PRIMARILY CONCERNED ABOUT SNOW ALONG THE INTERSTATE 15 CORRIDOR NEAR FILLMORE...WHICH TENDS TO BE FAVORED IN NORTHWEST FLOW. OTHERWISE GOING HEAVY SNOW WARNING FOR CENTRAL AND SOUTHWEST MOUNTAINS LOOKS IN GOOD SHAPE. EXPECT SNOW TO TAPER OFF DURING THE DAY SUNDAY AS 500MB TEMPS BEGIN TO WARM IN RESPONSE TO BUILDING SHORTWAVE RIDGE UPSTREAM. 700MB WARM ADVECTION ASSOCIATED WITH THIS RIDGE IS FORECAST TO OVERSPREAD THE FORECAST AREA MONDAY...WHICH MAY WELL BRING ANOTHER ROUND OF SNOWFALL ACROSS THE HIGHER TERRAIN. ACTIVE PATTERN LOOKS TO CONTINUE THROUGHOUT THE REMAINDER OF THE UPCOMING WEEK...AS YET ANOTHER SHORTWAVE TROUGH IS FORECAST BY GFS/EC TO TRANSLATE THROUGH THE FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. AT THIS TIME HAVE LEFT POPS BEYOND MONDAY IN THE SLIGHT CHANCE/CHANCE CATEGORY. && .AVIATION...NORTHWESTERLY WINDS TO DEVELOP AT KSLC DURING THE MORNING HOURS AS GRADIENT INCREASES BEHIND THE COLD FRONT. THE COOLING AIRMASS WILL SUPPORT RAIN SHOWERS TURNING TO SNOW SHOWERS BY MIDDAY. THIS WILL RESULT IN BRIEF PERIODS OF IFR CONDITIONS THIS AFTERNOON. VERY COLD NORTHWEST FLOW TONIGHT WILL LIKELY RESULT IN LAKE EFFECT SNOW BANDS AND MORE PERSISTENT IFR CONDITIONS THROUGH THE NIGHT. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...HEAVY SNOW WARNING THROUGH SUNDAY MORNING ZONES UTZ002>004-006>010-017. SNOW ADVISORY THIS AFTERNOON THROUGH SUNDAY MORNING ZONE UTZ015. WY...SNOW ADVISORY THROUGH TONIGHT ZONE WYZ021. && $$ PUBLIC...SEAMAN AVIATION...BRENCHLEY ut AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 930 PM CST SAT NOV 26 2005 .UPDATE... WILL BE EXPANDING THE AREA OF FREEZING DRIZZLE A LITTLE FARTHER SOUTH THAN THE CURRENT FORECAST. FORECAST SOUNDINGS FROM THE RUC INDICATE THAT IF LIGHT PRECIPITATION CAN DEVELOP BETWEEN 09Z AND 12Z...SURFACE TEMPERATURES FROM ABOUT WABASHA COUNTY EASTWARD INTO NORTHERN ADAMS AND JUNEAU COUNTIES WOULD STILL BE BELOW FREEZING. BY 12Z...THE SOUNDINGS INDICATE TEMPERATURES SHOULD BE AT OR JUST BELOW FREEZING. HOWEVER...THE RUC IS SLOWER TO BRING IN THE PRECIPITATION TO THESE AREAS AND DOES NOT START IT UNTIL ABOUT 12Z. THE 00Z NAM CONTINUES TO SUPPORT A WARMER SOLUTION FOR THESE AREAS AND AGREES WELL WITH THE ONGOING FORECAST DESPITE BREAKING PRECIPITATION OUT AROUND 09Z. CONFIDENCE DOES NOT EXIST AT THIS POINT TO EXPAND THE ADVISORY SOUTH BUT WILL CONTINUE TO MONITOR FOR A QUICK UPDATE TO THIS IF NEEDED. 04 .PREV DISCUSSION... .SHORT TERM...THROUGH TUESDAY NIGHT FORECAST CONCERNS CONTINUE TO FOCUSED ON SIGNIFICANT STORM SYSTEM TO AFFECT THE AREA SUNDAY THROUGH MONDAY. AFTERNOON SURFACE ANALYSIS HAD WARM FRONT EXTENDING ACROSS NORTHERN ILLINOIS AND CENTRAL IOWA TO LOW PRESSURE NEAR SOUTH DAKOTA/WYOMING BORDER. LARGE TEMPERATURE DIFFERENCE ACROSS THE FORECAST AREA... WITH READINGS RANGING FROM UPPER 20S IN NORTH CENTRAL WI...TO THE MID 40S IN PARTS OF NORTHEAST IOWA. SOUTH OF THE WARM FRONT... DEW POINTS WERE RISING INTO THE 40S ACROSS MISSOURI AND KANSAS. IN THE UPPER ATMOSPHERE...300MB 120KT JET ADVANCING INTO SOUTHWEST U.S. AS EVIDENCED BY HERRING-BONE LIKE PATTERN IN WATER VAPOR IMAGERY. 12Z 26NOV05 MODELS HAD COME INTO GOOD CONSENSUS ON STRONG STORM SYSTEM TO EVOLVE OVER THE CENTRAL PART OF THE NATION. IN THE LAST FEW DAYS...UKMET AND ECMWF HAVE HAD SLOWER AND FURTHER WEST TRACK OF OCCLUDED SURFACE LOW MOVING INTO UPPER MISSISSIPPI VALLEY. NAM AND GFS HAVE COME INTO AGREEMENT WITH THIS SOLUTION...WITH SURFACE LOW OVER NORTHWEST IOWA AT 12Z 28NOV05. ALTHOUGH THERE WERE DIFFERENCES IN THE LOW LEVEL THERMAL FIELDS ON MONDAY...FORECAST CONFIDENCE WAS OVERALL HIGH BASED ON MODEL CONSENSUS. TONIGHT...WARM AIR BEGINS PUSHING NORTHWARD IN EARNEST AS 850MB TEMPERATURES RISE TO AROUND 8C BY 12Z 27NOV05. MODEST ISENTROPIC LIFT NOTED IN THE 280K-290K LAYER...WHICH PROVIDES FORCING TO GENERATE PRECIPITATION ACROSS THE FORECAST AREA. INCREASED PRECIPITATION PROBABILITIES INTO LIKELY CATEGORY BASED ON FORCING SIGNAL. BUFR SOUNDINGS SUPPORT LIQUID PRECIPITATION MOST AREAS DUE TO PRONOUNCED ELEVATED WARM LAYER AND SURFACE TEMPERATURES EITHER RISING TO OR REMAINING ABOVE 32F. FURTHER NORTH...BEFORE DEEP CLOUD LAYER MOVES IN ACROSS NORTH CENTRAL WI...CONCERNED THAT FREEZING DRIZZLE WILL OCCUR LONG ENOUGH TO WARRANT AN ADVISORY. THUS...ISSUED WINTER WEATHER ADVISORY FOR WIZ017 09Z-15Z 27NOV05. SUNDAY AND SUNDAY NIGHT...CLOSED 500MB LOW EVOLVES OVER NATIONS MIDSECTION...AS SURFACE LOW PUSHES NORTHWARD OUT OF THE PLAINS AND OCCLUDES. STRONG SOUTHERLY FLOW AHEAD OF THIS SYSTEM EXPECTED TO BRING DEEP LAYER OF RELATIVE HUMIDITY THROUGH THE TROPOSPHERE AS SHOWN BY TIME/HEIGHT CROSS SECTIONS. LARGE SCALE ASCENT IMPRESSIVE ASSOCIATED WITH LOW LEVEL WARM AIR ADVECTION...ALONG WITH UPPER LEVEL DIVERGENCE IN LEFT FRONT REGION OF 300MB JET. IN ADDITION...ELEVATED CAPE VALUES OF 300-400 J/KG INDICATED SUNDAY NIGHT. STRONG DYNAMICS ASSOCIATED WITH THE SURFACE AND UPPER LEVEL LOW CERTAINLY SUGGEST WIDESPREAD RAINFALL EVENT SUNDAY AND SUNDAY NIGHT. CURRENT DATA BASE APPEARS QUITE REASONABLE WITH RESPECT TO RAIN PROBABILITIES AND QPF. MAINTAINED ISOLATED THUNDERSTORM POTENTIAL SUNDAY NIGHT BASED ON ELEVATED INSTABILITY. IN ADDITION...ADDED FOG TO SUNDAY NIGHT IN PORTIONS OF SOUTHEAST MN AND NORTHEAST IOWA... WHERE SOUTHEAST WINDS OVER MELTING SNOW SUPPORT SIGNIFICANTLY REDUCED VISIBILITY DUE TO FOG. WARMING TREND SUPPORTED BY RISING 850MB AND SURFACE TEMPERATURES. HOWEVER...WE WERE CONCERNED THE MODELS WARMED THE NEAR-SURFACE AIR TOO MUCH TONIGHT THROUGH SUNDAY NIGHT. THIS BASED ON FRESH SNOW COVER OVER MUCH OF THE FORECAST AREA...WHICH THE MODELS HAVE NOT ACCOUNTED FOR. IN ADDITION...AS TEMPERATURES RISE ABOVE 32F...MELTING SNOW SHOULD PRIME THE BOUNDARY LAYER FOR LOW CLOUDS AND/OR FOG. THUS... MAINTAINED NON-DIURNAL TREND IN DATA BASE...WITH TEMPERATURES ANTICIPATED TO CONTINUE RISING THROUGH SUNDAY NIGHT...BUT NOT AS MUCH AS MOS GUIDANCE SUGGESTED. MONDAY...STRONG 850MB COLD AIR ADVECTION INDICATED AS COLDER AIR WRAPS AROUND THE OCCLUDED LOW. WE HAD SOME UNCERTAINTY ABOUT PRECIPITATION TYPE AS A RESULT OF GFS AND NAM FORECAST SOUNDING AND COBB OUTPUT DIFFERENCES. FOR EXAMPLE...NAM SOUNDINGS AND COBB OUTPUT SUGGEST RAIN CHANGES TO ALL SNOW ACROSS MUCH OF SOUTHEAST MN AND NORTHEAST IOWA. ON THE OTHER HAND...GFS FORECAST SOUNDINGS AND COBB OUTPUT SUPPORTED A WARMER SCENARIO...WITH RAIN IN THE AFOREMENTIONED LOCATIONS INTO THE AFTERNOON. DUE TO UNCERTAINTY...MAINTAINED DATA BASE AS IS...WITH RAIN OR SNOW GENERALLY WEST OF THE MISSISSIPPI RIVER AND ALL RAIN FROM THE MISSISSIPPI RIVER EASTWARD INTO WI. .LONG TERM...WEDNESDAY THROUGH SATURDAY WEDNESDAY INTO THURSDAY...BOTH ECMWF AND GFS INDICATED AN UPPER LEVEL AND SURFACE WAVE SHOULD MOVE ACROSS THE MIDWEST. APPEARS THERE COULD BE ENOUGH FORCING TO PRODUCE A LIGHT SNOW EVENT. MAIN IMPACT ON THE FORECAST WAS TO INCLUDE CHANCE OF SNOW WEDNESDAY NIGHT AS THIS TIME PERIOD WAS PRECIPITATION FREE IN THE CURRENT DATA BASE. FRIDAY INTO SATURDAY...NEXT SYSTEM TO AFFECT THE UPPER MISSISSIPPI VALLEY COULD BRING PRECIPITATION DURING THE WEEKEND...DECEMBER 3-4. DUE TO ENSEMBLE AND OPERATIONAL MODEL DIFFERENCES IN TIMING AND POSITION OF SURFACE AND UPPER LEVEL FEATURES...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE PRECIPITATION ON DAY 7...SATURDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ THOMPSON wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 315 AM CST SUN NOV 27 2005 .SHORT TERM...SUNDAY THROUGH WEDNESDAY NIGHT PRECIPITATION TOOK A WHILE TO MAKE IT INTO THE CWA SATURDAY AND LOOKING BACK...IT APPEARS THE GFS ACTUALLY HAD THE BETTER TIMING. WITH OVERRRUNING EVENT WRAPPING UP EARLY THIS MORNING...ITS TIME TO CONCENTRATE ON THE DEVELOPING CONVECTIVE EVENT SLATED FOR LATER THIS AFTERNOON AND TONIGHT. WHILE NAM AND GFS ARE BOTH DEEPER AND SLOWER WITH THE SYSTEM TONIGHT...STILL LIKE THE GFS SOLUTION. BASED ON THE CONTINUITY OF THE GFS AND ITS HANDLING OF THE SYSTEM MOVING THROUGH NOW...SEE NO REASON TO DEVIATE AWAY FROM IT. OVERRUNNING/WARM AIR ADVECTION PRECIPITATION CONTINUING TO MOVE TOWARDS THE NORTH AS WEAKENING MID LEVEL WAVE OVER THE CENTRAL GULF COAST LIFTS OFF TO THE NORTHEAST. MAJORITY OF THE PRECIPITATION WILL BE OVER BY PRESS TIME BUT WILL STILL HOLD ON TO SOME MINIMAL POPS EARLY OVER THE NORTHEAST PART OF THE CWA AS RUC13 MODEL HOLDS ON TO SOME LIGHT PRECIP THROUGH MID MORNING. MAJORITY OF THE DAY WILL BE DRY AS AREA WILL BE BETWEEN SYSTEMS BUT RAIN CHANCES WILL BE INCREASING ONCE AGAIN THIS AFTERNOON AS NEXT SYSTEM APPROACHES FROM THE WEST. MAJOR PLAYERS STILL SHOWING UP QUITE NICELY ON WATER VAPOR IMAGERY THIS MORNING...MAINLY THE EXITING MID LEVEL WAVE AND THE VIGOROUS UPPER LEVEL SYSTEM CURRENTLY OVER THE ROCKIES. DEEP TROF EVIDENT JUST SOUTH OF THE 4 CORNERS WITH STRONG IMPULSE ROTATING THROUGH ITS BASE ACROSS NORTHERN ARIZONA/NEW MEXICO. SYSTEM STILL LOOSELY ORGANIZED AT THE MOMENT BUT BUT EXPECTED TO QUICKLY INTENSIFY LATER THIS MORNING AS IT LIFTS OUT INTO THE CENTRAL PLAINS. LEE CYCLOGENESIS ALREADY UNDERWAY OVER THE CENTRAL PLAINS. SURFACE LOW ALSO EXPECTED TO DEEPEN RAPIDLY THIS MORNING IN RESPONSE TO THE EXIT REGION OF MID LEVEL JET MOVING THROUGH. SURFACE LOW EXPECTED TO BE IN NORTH CENTRAL OKLAHOMA BY MID DAY AND RACING OFF INTO SOUTHERN IOWA BY MONDAY MORNING. PROJECTED PATH WOULD KEEP AREA IN WARM SECTOR THE ENTIRE DAY WITH SOUTHERLY WINDS PROVIDING GOOD MOISTURE RETURN. GRADIENT BETWEEN SYSTEMS LOOKS PRETTY TIGHT AND WILL HOIST A LAKE WIND ADVISORY FOR THE ENTIRE CWA FOR TODAY. EXPECTING SQUALL LINE TO DEVELOP IN ADVANCE OF THE ATTENDANT COLD FRONT THIS AFTERNOON OVER THE CENTRAL PLAINS WHICH WILL THEN SWEEP THROUGH THE STATE LATE THIS AFTERNOON AND EVENING. STRONG DIFFLUENCE NOTED ALOFT ALONG WITH GOOD SURFACE CONVERGENCE BUT INSTABILITY APPEARS MARGINAL AT BEST RIGHT NOW. HOWEVER...THERE IS SOME CONCERN THAT COULD CHANGE. WIDESPREAD CLOUD COVER TODAY SHOULD KEEP INSTABILITY IN CHECK BUT ANY SIGNIFICANT CLEARING COULD LEAD TO EXPLOSIVE DEVELOPMENT ALONG THE FRONT. BIGGEST THREAT APPEARS TO BE STRAIGHT LINE WINDS WITH FAST MOVING LINE WHICH WILL BE LOCATED NEAR THE MISSISSIPPI RIVER NEAR MIDNIGHT. WILL END THE PCPN ACROSS THE AREA FROM WEST TO EAST SUNDAY EVENING AS FRONT MOVES THROUGH. AFTER SOME BRIEF CLEARING SUNDAY NIGHT/EARLY MONDAY...LARGE SLUG OF MOISTURE WILL ROTATE AROUND THE MAIN LOW MONDAY AFTERNOON THROUGH EARLY TUESDAY AS TROF AXIS PASSES THROUGH. NO PRECIPITATION EXPECTED. TEMPERATURES WILL COOL OF INITIALLY BEHIND THE FRONT WITH STRONGER COLD AIR AIR ADVECTION BEHIND THE PASSAGE OF THE TROF. HIGH PRESSURE WILL BUILD IN FROM THE SOUTHERN PLAINS BY MIDDAY TUESDAY FOR DRY AND COOL CONDITIONS TUESDAY. TEMPERATURES WILL MODERATE WEDNESDAY AS CENTER OF THE HIGH MOVES EAST AND WINDS RETURN TO A SOUTHERLY DIRECTION AND FLOW ALOFT STARTS TO BECOME MORE ZONAL. MAV NUMBERS LOOK PRETTY GOOD BUT WILL GO ABOVE GUIDANCE ON WEDNESDAY. && .LONG TERM...THURSDAY THROUGH SATURDAY LARGE VORTEX TO OUR NORTHEAST WILL CONTINUE MOVING AWAY FROM THE STATE WHILE RIDGE AMPLIFIES TO OUR WEST. H5 RIDGE WILL BE JUST EAST OF AR BY 00Z SUN...AND IT WILL BE CLOSE TO THE EAST COAST BY SUNDAY MORNING. IN THE MEANTIME...ANOTHER LONG WAVE TROF WILL BE TRAVERSING THE ROCKIES. THE SURFACE PATTERN WILL BEGIN THE PERIOD WITH A COLD FRONT HAVING JUST EXITED THE SOUTHEAST CORNER OF THE STATE. HIGH PRESSURE WILL PUSH DRIER AIR OVER THE STATE FROM THE NORTH...WHILE HOLDING OFF GULF MOISTURE ALONG THE COAST BY 00Z FRIDAY. HIGHER RH VALUES WILL MOVE NORTH THROUGH LA OVERNIGHT INTO FRIDAY MORNING... BUT THEY DO NOT QUITE PUSH INTO THE STATE. I WILL HAVE TO HOLD OFF ANY MENTION OF RAIN UNTIL LATE IN THE DAY SATURDAY. TEMPS WILL BE CLOSE TO NORMAL THURSDAY...AND THEY WILL TAKE A DIP BELOW NORMAL FOR FRIDAY AND SATURDAY. && .PRELIMINARY POINT TEMPS/POPS... LITTLE ROCK AR 72 50 61 38 / 60 70 10 10 HARRISON AR 68 45 55 32 / 60 60 10 10 HOT SPRINGS AR 73 50 60 38 / 60 70 10 10 PINE BLUFF AR 74 52 63 39 / 60 80 10 10 MOUNTAIN HOME AR 68 46 57 32 / 60 70 10 10 MONTICELLO AR 75 54 65 40 / 60 80 10 10 SEARCY AR 72 50 60 37 / 60 80 10 10 MOUNT IDA AR 72 49 60 37 / 60 70 10 10 RUSSELLVILLE AR 71 48 58 36 / 60 70 10 10 && .LZK WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY FROM 10 AM SUNDAY TO 6 PM SUNDAY FOR ARZ003- ARZ004-ARZ005-ARZ006-ARZ007-ARZ012-ARZ013-ARZ014-ARZ015-ARZ016- ARZ021-ARZ022-ARZ023-ARZ024-ARZ025-ARZ030-ARZ031-ARZ032-ARZ033- ARZ034-ARZ037-ARZ038-ARZ039-ARZ040-ARZ041-ARZ042-ARZ043-ARZ044- ARZ045-ARZ046-ARZ047-ARZ052-ARZ053-ARZ054-ARZ055-ARZ056-ARZ057- ARZ062-ARZ063-ARZ064-ARZ065-ARZ066-ARZ067-ARZ068-ARZ069. && $$ SHORT TERM...56 / LONG TERM....32 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 444 AM EST SUN NOV 27 2005 .SHORT TERM...TODAY AND TONIGHT LOW LEVEL WARMING MOIST SOUTHERLY FLOW THROUGH TONIGHT...AS MID LEVEL SHORTWAVE RIDGE GETS SHOVED NORTHEAST WITH CLOSED LOW...AS AT 500 MB...TAKING SHAPE OVER THE CENTRAL PLAINS AND APPROACHING THE MID MISSISSIPPI VALLEY LATE TONIGHT. 850 TO 500 MB MOISTURE SEEN BY MODELS TO RAPIDLY IMPROVE EARLY THIS MORNING...THEN DROPPING OFF BY LATE TONIGHT. 925 MB MOISTURE ESPECIALLY GOOD THIS MORNING AND AGAIN TONIGHT. PRECIPITABLE WATER RISING TO AROUND AN INCH EARLY TODAY...AS 295K ISENTROPIC SURFACE SPECIFIC HUMIDITY VALUES RISE TO NEAR 6 G/KG. LOW TO MID LEVEL OMEGA LIFT MODEST AT TIMES THROUGH TONIGHT. 850 TO 500 MB QVECTOR CONVERGENCE SLIGHT TODAY INTO TONIGHT. MODEST 850 TO 500 MB FRONTOGENETICAL FORCING THIS AFTERNOON/EVENING...ACCOMPANIED BY MODEST UPPER LEVEL DIVERGENCE. 295K ISENTROPIC LIFT SEEN BY NAM AND GFS WITH BEST SURGE THIS MORNING...AGAIN THIS AFTERNOON INTO THIS EVENING BEFORE WANING. CONDENSATION PRESSURE DEFICITS RAPIDLY LOWERING TO AROUND 30 MB EARLY THIS MORNING TO LEND SUPPORT FOR RAIN. MINIMAL CHANGES FROM EARLIER FORECASTS FOR RAIN TODAY AND TONIGHT. MELTING SNOW WILL AID FOG DEVELOPMENT AND MAINTENANCE AS TEMPERATURES AND DEW POINTS CLIMB. 00Z WRFXX AND GFS SEEM TO HAVE BEST HANDLE ON AREAL EXTENT OF RAIN MOVING UP FROM THE SOUTH. && .LONG TERM...MONDAY THROUGH SATURDAY STRONG UPPER LEVEL CLOSED LOW WITH 500MB HEIGHTS AROUND 5280M...WILL START THE DAY OVER SOUTHERN IOWA. THIS FEATURE AND THE ASSOCIATED 984MB SURFACE LOW WILL BOTH START TO FILL AS A JET STREAK MOVES UP THE EAST SIDE OF THE TROUGH...CAUSING THE ENTIRE SYSTEM TO ACCELERATE NORTHEASTWARD. THIS SYSTEM BECOMES STRONGLY OCCLUDED ON MONDAY WITH THE COLD FRONT REACHING ALL THE WAY NORTH TO LAKE SUPERIOR WHILE THE SURFACE LOW LAGS OVER SOUTHWESTERN WISCONSIN. THE FRONTAL PUSH ITSELF WILL BE FAIRLY WEAK ACROSS SOUTHEAST MICHIGAN DURING THE AFTERNOON AS WINDS SHIFT FROM SOUTHEAST TO SOUTH-SOUTHWEST BEHIND THE FRONT WITH NEARLY UNI-DIRECTIONAL SOUTHERLY FLOW THROUGH THE COLUMN. THE FRONT HAS ALSO SLOWED A BIT ALLOWING TEMPS TO CLIMB TO NEAR 60 ACROSS THE SOUTH AHEAD OF THE FRONT. AM STILL EXPECTING TO SEE A PERIOD OF SHOWERS WITH GOOD LOW LEVEL FRONTAL FORCING DURING THE AFTERNOON/EARLY EVENING. THIS LIFT IS STRONGEST ACROSS THE SOUTHERN HALF OF THE CWA WHERE THERE IS ALSO BETTER INSTABILITY. TIMING LOOKS A BIT OFF FOR THUNDERSTORMS ON MONDAY AS INSTABILITY IN NOT IMPRESSIVE WITH LOW LEVEL LIFT COMING WHILE 500MB TEMPS ARE IN THE -14 TO -16C RANGE. LOCAL WRFXX HEMISPHERIC MODELS SHOWS A BIT MORE PROMISE WITH AROUND 400 J/KG OF CAPE...BUT IS AN OUTLIER FROM THE REST OF THE MODELS WITH THE LOCATION OF THE UPPER LOW. STILL FEEL BEST CHANCES OF THUNDERSTORMS WILL BE FROM CENTRAL INDIANA SOUTHWARD WHERE THE AIRMASS IS MORE FAVORABLE AND FRONTAL FORCING STRONGER...SO WILL CONTINUE WITH RAIN SHOWERS DURING THE AFTERNOON AND LEAVE THE THUNDERSTORMS OUT. WILL CONTINUE LIKELY POPS INTO THE EVENING AS IT LOOKS LIKE IT WILL BE MID EVENING UNTIL DRY SLOT CUTS OFF SHOWERS. THE UPPER LEVEL CLOSED LOW WILL OPEN...LIFTING NORTHEAST TOWARDS THE POLAR LOW OVER ONTARIO THROUGH TUESDAY MORNING. TEMPS WILL COOL THROUGHOUT THE DAY ON TUESDAY AS COLD AIR ADVECTION CONTINUES WITH LIGHT INSTABILITY SHOWERS POSSIBLE. 1000-850MB THICKNESSES WILL ONLY BE DOWN TO AROUND 1300M BY MONDAY AFTERNOON WITH 850MB TEMPS OF -8C. THIS WILL LEAVE PRECIP TYPE ON THE FENCE THROUGH AT LEAST MID AFTERNOON TRANSITIONING TO SNOW FROM WEST TO EAST. UPPER LEVEL TROUGH WILL STILL REMAIN OVER THE MIDWEST WITH SHORTWAVES MOVING THROUGH IT...UNTIL FINALLY LIFTING NORTHEAST OF THE REGION ON WEDNESDAY. A SURFACE LOW WILL DEVELOP AHEAD OF THE WAVE OVER NEW ENGLAND WITH A SURFACE TROUGH EXTENDING WEST TO THE CENTRAL GREAT LAKES. HIGH PRESSURE BUILDING OVER THE OHIO RIVER VALLEY ON WEDNESDAY WILL INFLUENCE SOUTHERN MICHIGAN...WITH FLURRIES TAPERING OFF BY THE AFTERNOON. UPPER LEVEL RIDGING ON WEDNESDAY WILL GIVE WAY TO THE NEXT TROUGH DROPPING OUT OF CANADA ON THURSDAY. DIFFERENCES IN TIMING AND ORIENTATION OF THIS TROUGH WILL IMPACT THE TRACK OF THE ASSOCIATED SURFACE LOW CONSIDERABLY FOR THE END OF THE WEEK. INITIAL INDICATIONS SHOW WE MAY WARM UP SLIGHTLY WEDNESDAY/WEDNESDAY NIGHT BEFORE COOLING BACK DOWN THURSDAY INTO FRIDAY. HAVE MADE FEW CHANGES TO THE FORECAST LEAVING LOW POPS IN FOR THURSDAY AND FRIDAY AS IT IS STILL TOO EARLY TOO HIGHLIGHT A PERIOD WITH HIGHER CHANCES. && .PREV DISCUSSION... (ISSUED 1153 PM EST SAT NOV 26 2005) AVIATION... LOW LEVEL MOISTURE ADVECTION HAS RESULTED IN THE EXPANSION OF A STRATUS DECK BASED AROUND 4500 FT ACROSS SOUTHERN MICHIGAN. SOME MVFR CEILINGS ARE LIFTING NORTH ACROSS INDIANA AND OHIO ASSOCIATED WITH SOME 925MB MOISTURE ADVECTION. BASED ON THE LATEST RUC...THESE CLOUDS SHOULD REACH THE DETROIT AREA AROUND 08Z AND MBS BY 10Z. LOOKS LIKE THE BEST LIFT WILL ARRIVE INTO SE MICHIGAN IN A SERIES OF WAVES. THE FIRST SHOULD ARRIVE AFTER 10Z AS STRONG LOW LEVEL MOISTURE ADVECTS NORTH ACROSS THE AREA. THE COMBINATION OF RAIN AND SNOWMELT WILL RESULT IN MVFR CEILINGS AND VISIBILITY. THE NEXT AREA OF LIFT SHOULD ARRIVE LATE IN THE AFTERNOON AND PERSIST THROUGH THE END OF THE TAF PERIOD AS AN UPPER SHORT WAVE LIFTS ACROSS THE STATE. THE 18Z NAM AND GFS INDICATE A BRIEF PERIOD OF VFR CONDITIONS AROUND DETROIT IN THE MID AFTERNOON BEFORE THE NEXT WAVE ARRIVES...WITH FNT AND MBS REMAINING MVFR. WILL KEEP CEILINGS AND VISIBILITY MVFR LATE IN THE TAF PERIOD. PERSISTENT SURFACE MOISTURE ADVECTION OVER THE RECENT SNOWMELT MAY HOWEVER CREATE IFR OR LIFR VISIBILITIES TOWARD THE END OF THE TAF PERIOD. THIS WILL CONTINUE TO BE MONITORED. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ441...4 PM SUNDAY TO 6 PM MONDAY. SMALL CRAFT ADVISORY...SAGINAW BAY-LHZ442-LHZ443...7 PM SUNDAY TO 6 PM MONDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DWD LONG TERM....KAHL AVIATION...CONSIDINE YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 404 AM EST SUN NOV 27 2005 .DISCUSSION... MAIN FORECAST CONCERNS ARE FREEZING RAIN THIS MORNING AND DENSE FOG TONIGHT. CURRENT WEATHER...09Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPPER RIDGE COVERING MUCH OF THE EAST HALF OF THE U.S. WHILE AN UPPER TROUGH WAS LOCATED OVER THE INTERMOUNTAIN WEST. ONE SHEARING OUT SHRTWV CAN BE SEEN OVER MISSOURI HEADING NE. A MORE INTENSE STRETCHED OUT SHRTWV...NOTED BY DRYING ON WATER VAPOR... EXTENDED FROM NE ARIZONA INTO SOUTHERN NEW MEXICO (NOTED BY DRYING ON WATER VAPOR). AN UPPER LOW WAS ALSO LOCATED WITHIN THE TROUGH NEAR GRAND JUNCTION COLORADO. ON THE SOUTH SIDE OF THE SHRTWV...250MB WINDS WERE ON THE ORDER OF 130-140KT PER 00Z RUC ANALYSIS. AHEAD OF THE SHRTWV OVER THE PLAINS...STRONG WARM AND MOISTURE ADVECTION HAS BEEN OCCURRING WITH SURFACE WINDS OUT OF THE SOUTH FROM 15-25KT. SURFACE DEWPOINTS OF 50 F OR GREATER HAVE NOW ADVECTED INTO PORTIONS OF NEBRASKA AND IOWA. 00Z TOPEKA SOUNDING ALSO INDICATED AN 850MB DEWPOINT OF 9C WITH A PRECIPITABLE WATER OF 0.87 INCHES. ALL OF THIS MOISTURE AND WARMER AIR IS LOCATED ON THE SOUTH SIDE OF A WARM FRONT STILL ALONG I-80 FROM EASTERN NEBRASKA TO CLEVELAND. THIS FRONT THEN EXTENDS SOUTHWEST TO A 992MB LOW NEAR DODGE CITY. CLOSER TO HOME...SE LOW LEVEL FLOW CONTINUES ON THE NORTH SIDE OF THE WARM FRONT. PLENTY OF LOW CLOUD (NEAR MVFR CEILINGS) HAS FORMED ACROSS THE WESTERN 2/3 OF UPPER MICHIGAN DUE TO UPSLOPE OFF OF LAKE MICHIGAN (DEWPOINTS AT MNM...ESC AND ISQ ARE IN THE UPPER 20S). NO FREEZING DRIZZLE HAS OCCURRED YET THOUGH. DRIER LOW LEVEL AIR IS LOCATED OVER NORTHERN LOWER MICHIGAN WHERE DEWPOINTS ARE IN THE TEENS. MORE HIGHER BASED STRATOCUMULUS ARE SPREADING NORTH FROM SOUTHERN PORTIONS OF MINNESOTA...WISCONSIN AND MICHIGAN. IN FACT...LATEST RADAR LOOPS...SURFACE OBS AND LIGHTNING PLOTS ARE NOW SHOWING SCATTERED SHOWERS AND THUNDERSTORMS FROM SE MN INTO SW LOWER MI. THESE THUNDERSTORMS ARE IN AN AREA OF 700-850MB NEGATIVE EPV (MAINLY THETA-E DECREASING WITH HEIGHT). TODAY...SHRTWV OVER THE SOUTHWEST IS PROGGED TO MOVE INTO CENTRAL OKLAHOMA THIS EVENING...PULLING THE UPPER LOW INTO FAR SOUTH CENTRAL KANSAS. INCREASING DPVA ALONG WITH INCREASED WARM ADVECTION AND POSSIBILITY FOR CONVECTION SHOULD ALLOW THE SURFACE LOW TO DEEPEN INTO THE 980S MB BY 00Z. WARM ADVECTION AHEAD OF THE SHRTWV WILL EVEN BE FELT ALL THE WAY NORTH INTO UPPER MICHIGAN AS MODEL PROGS SHOW 850MB TEMPS RISING TO 6C BY 00Z. THIS WARM ADVECTION SHOULD PUSH THE WARM FRONT NEAR I-80 ACROSS THE CWA THIS AFTERNOON WHILE A NEW WARM FRONT SETS UP OVER THE OHIO VALLEY AS THE LOW DEEPENS. ISENTROPIC LIFT SEEN ON THE 295K SURFACE IN CONJUNCTION WITH DPVA AHEAD OF THE SHEARED OUT SHRTWV IN MISSOURI AND IOWA HEADING INTO WISCONSIN SHOULD ALLOW FOR THE DEVELOPMENT OF MORE RAIN THIS MORNING ACROSS WISCONSIN AS MID-LEVEL MOISTEN...SPREADING NORTH INTO THE CWA BY LATE MORNING AND ACROSS THE CWA THIS AFTERNOON. THERE IS A POSSIBILITY THAT TEMPERATURES MAY NOT BE ABOVE FREEZING WHEN THIS RAIN MOVES IN SO HAVE INSERTED FREEZING RAIN LIKELY INTO THE GRIDS ALONG THE WISCONSIN BORDER. IT LOOKS LIKE IT WILL BE A BRIEF PERIOD THOUGH. UNTIL THEN...NOT MUCH IN THE WAY OF PRECIPIATION LOOKS TO OCCUR...PERHAPS SOME PATCHY DRIZZLE DUE TO UPSLOPE. FIGURE TOO THAT ONCE RAIN STARTS...WHICH IS EXPECTED TO BE A WARM RAIN GIVEN THE HIGHER 850MB TEMPS...MELTING OF THE SNOWPACK SHOULD RESULT IN SOME FOG DEVELOPMENT. THIS WILL BE PARTICULAR TRUE BY LATE AFTERNOON WHEN MORE MELTING HAS OCCURRED AND HIGHER DEWPOINTS ADVECT INTO THE CWA ACROSS THE SNOWPACK. DESPITE THAT THERE IS LIGHTNING WITH THE SHOWERS TO THE SOUTH...HAVE NOT MENTIONED ANY THUNDER IN THE FORECAST. LOOKING AT RUC CROSS-SECTIONS...THE AREA OF NEGATIVE EPV IS PROGGED TO WEAKEN AS IT MOVES INTO UPPER MICHIGAN WHICH SEEMS REASONABLE AS CONVECTION THAT DOES GO AT NIGHT IS USUALLY SUPPORTED BY A NOCTURNAL LOW LEVEL JET. EXPECT TEMPERATURES TO BE HELD DOWN BY THE RAIN AND THICK CLOUD COVER. CURRENT GOING HIGHS SEEM REASONABLE. TONIGHT...DIFFERENCES AMONGST THE MODELS ALREADY APPEAR WITH HOW FAST THE UPPER LOW AND SHRTWV EJECT TO THE NORTHEAST. THE UKMET IS SLOWEST...SHOWING THE UPPER LOW NEAR OTTAWA KANSAS AT 12Z MON WHEREAS THE GFS AND CANADIAN HAVE IT ALREADY INTO SOUTH CENTRAL IOWA. THE NAM IS HALF-WAY INBETWEEN. TRENDS WITH MODELS HAVE BEEN SLOWER AND DEEPER WITH THIS SYSTEM AND THEREFORE WILL FOLLOW THE UKMET. RAIN ASSOCIATED WITH SHEARED SHRTWV SHOULD PERSIST INTO THE EVENING HOURS...BUT THEN MAY TAPER OFF TO DRIZZLE OR NOTHING AFTER MIDNIGHT AS SYSTEM DEEPENS IN THE CENTRAL PLAINS. UKMET SUGGESTS UPPER LEVEL RIDGING MOVING OVER THE CWA BETWEEN 06-12Z MON WITH 850MB FLOW BECOMING DIVERGENT. WILL THEREFORE TONE DOWN PRECIP WORDING A BIT AFTER MIDNIGHT. THIS DIMINISHING TREND IN RAIN IN CONJUNCTION WITH EVEN HIGHER SURFACE DEWPOINTS ADVECTING INTO THE CWA LOOKS REALLY GOOD FOR DENSE FOG SETUP. ONLY QUESTION AREA FOR FOG IS MENOMINEE AND DELTA COUNTIES WHERE THE SNOWPACK IS ONLY A FEW INCHES. HAVE NOT ISSUED A DENSE FOG ADVISORY YET SINCE IT IS SECOND PERIOD...BUT HAVE HIT IT UP HARD IN THE GRIDS AND ZFP. AN ADVISORY WILL LIKELY BE NEEDED IF CONDITIONS FOR DENSE FOG STILL LOOK GOOD. AS FAR AS LOWS GO...TEMPERATURES SHOULD RISE THROUGH THE NIGHT DUE TO RISING DEWPOINTS. MONDAY...CONTINUING TO FOLLOW THE UKMET...SHRTWV AND ASSOCIATED UPPER LEVEL JET ARE PROGGED TO MOVE INTO CENTRAL UPPER MICHIGAN AROUND 00Z TUE WHILE A 986MB LOW MOVES INTO SE MN. AS THIS SHRTWV APPROACHES...WARM AIR ADVECTION INTENSIFIES (CONFLUENCE AT 850MB) AND UPPER DIVERGENCE DEVELOPS FROM THE LEFT EXIT REGION...EXPECT BANDS OF SHOWERS TO MOVE IN BY LATE MORNING AND CONTINUE THROUGH THE AFTERNOON. SHOWALTER INDICES ARE PROGGED TO DROP TO AROUND 1C...THEREFORE ALSO EXPECTING SOME EMBEDDED THUNDERSTORMS. RAIN MAY TAPER OFF LATE IN MENOMINEE COUNTY AS THE DRY-SLOT ASSOCIATED WITH THE SHRTWV MOVES IN...BUT HAVE DECIDED NOT TO INCLUDE THAT SINCE IT IS STILL CONCEIVABLE OF THIS SYSTEM SLOWING DOWN MORE BASED ON MODEL TRENDS. RAISED HIGH TEMPERATURES ABOUT 5 DEGREES BASED ON LATEST MAV GUIDANCE AND GIVEN THE HIGH DEWPOINTS TO THE SOUTH. WOULD NOT BE SURPRISED TO HAVE TO RAISE TEMPERATURES MORE IF DEWPOINTS ARE TOO LOW. MONDAY NIGHT INTO TUESDAY...UPPER LOW IS EXPECTED TO MOVE OVER UPPER MICHIGAN BY 12Z TUE AND THEN LIFT INTO ONTARIO AS A NEW SHRTWV TROUGH DROPS INTO THE PACIFIC NW. WITH THE UPPER LOW MOVING INTO THE CWA...MUCH OF THE AREA SHOULD BE DRY-SLOTTED MONDAY NIGHT. AS A RESULT...HAVE ADDED THE CHANCE OF DRIZZLE TO THE RAIN. OTHER CHANGE WAS TO DELAY THE SWITCHOVER TO SNOW AS EVEN AT 12Z TUE...THE UKMET IS KEEPING 850MB TEMPS AROUND 0C. BETTER COLD AIR ADVECTION MOVES IN ON TUE AS THE UPPER LOW EXITS THE AREA. 850MB TEMPS ARE EXPECTED TO DROP TO -6 TO -8C DURING THE AFTERNOON WHICH IS CLOSE TO HAVING LAKE EFFECT. A LITTLE COOLER AIR SHOULD MOVE IN TUESDAY NIGHT AND WITH THE NOCTURNAL CYCLE BETTER FOR LES AT NIGHT...THINK BETTER CHANCES FOR SNOW WILL THEREFORE BE TUESDAY NIGHT. TEMPERATURES SHOULD BE ABOVE AVERAGE FOR MONDAY NIGHT BUT THEN FALL DURING THE DAY ON TUESDAY AS COLD AIR ADVECTION TAKES HOLD. NO OTHER CHANGES MADE TO THE REST OF THE FORECAST. && .MQT...WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL NOON EST FOR MIZ002-004>006-009>014-084-085. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1153 PM EST SAT NOV 26 2005 .AVIATION... LOW LEVEL MOISTURE ADVECTION HAS RESULTED IN THE EXPANSION OF A STRATUS DECK BASED AROUND 4500 FT ACROSS SOUTHERN MICHIGAN. SOME MVFR CEILINGS ARE LIFTING NORTH ACROSS INDIANA AND OHIO ASSOCIATED WITH SOME 925MB MOISTURE ADVECTION. BASED ON THE LATEST RUC...THESE CLOUDS SHOULD REACH THE DETROIT AREA AROUND 08Z AND MBS BY 10Z. LOOKS LIKE THE BEST LIFT WILL ARRIVE INTO SE MICHIGAN IN A SERIES OF WAVES. THE FIRST SHOULD ARRIVE AFTER 10Z AS STRONG LOW LEVEL MOISTURE ADVECTS NORTH ACROSS THE AREA. THE COMBINATION OF RAIN AND SNOWMELT WILL RESULT IN MVFR CEILINGS AND VISIBILITY. THE NEXT AREA OF LIFT SHOULD ARRIVE LATE IN THE AFTERNOON AND PERSIST THROUGH THE END OF THE TAF PERIOD AS AN UPPER SHORT WAVE LIFTS ACROSS THE STATE. THE 18Z NAM AND GFS INDICATE A BRIEF PERIOD OF VFR CONDITIONS AROUND DETROIT IN THE MID AFTERNOON BEFORE THE NEXT WAVE ARRIVES...WITH FNT AND MBS REMAINING MVFR. WILL KEEP CEILINGS AND VISIBILITY MVFR LATE IN THE TAF PERIOD. PERSISTENT SURFACE MOISTURE ADVECTION OVER THE RECENT SNOWMELT MAY HOWEVER CREATE IFR OR LIFR VISIBILITIES TOWARD THE END OF THE TAF PERIOD. THIS WILL CONTINUE TO BE MONITORED. && .UPDATE... ISSUED AT 1032 PM THE 03 SURFACE ANALYSIS SHOWS A FRONTAL BOUNDARY EXTENDING FROM JUST NORTH OF CHICAGO ACROSS EXTREME SW LOWER MI...THEN INTO NORTH CENTRAL OHIO. THIS FRONT WILL SLOWLY PUSH NORTH DURING THE NIGHT. THETA E ADVECTION NEAR 850MB IS ONGOING ACROSS SOUTHERN MICHIGAN AND IS RESULTING IN AN EXPANDING STRATUS DECK. THIS STRATUS WILL EVENTUALLY WORK INTO THE SAGINAW VALLEY AND THUMB DURING THE OVERNIGHT. WITH WARM AIR ADVECTION ABOVE THE NOCTURNAL BOUNDARY LAYER AND WITH THE EXPANDING CLOUD COVER... TEMPS SHOULD SLOWLY RISE OVERNIGHT. THE 00Z UPPER AIR PLOTS SHOWED A MOISTURE GRADIENT NEAR 700MB ACROSS THE OHIO VALLEY. THIS MOISTURE ADVECTION WILL LIFT INTO THE SOUTHERN GREAT LAKES OVERNIGHT AS AN UPPER TROUGH OVER THE SOUTHERN PLAINS LIFTS INTO THE MID MISSISSIPPI VALLEY. THIS 700MB MOISTURE ADVECTION HAS TRIGGERED SOME RADAR RETURNS ACROSS NORTH CENTRAL OHIO. THUS THINK THE CURRENT CHANCE POPS ACROSS THE SOUTH OVERNIGHT LOOK REASONABLE AS THE MOISTURE WORKS INTO THE AREA. THE CURRENT FORECAST LOOKS TO HAVE A GOOD HANDLE ON TEMPERATURE TRENDS AND PRECIP CHANCES OVERNIGHT. SO NO UPDATE WILL BE ISSUED. && .SHORT TERM...TONIGHT AND SUNDAY SHORTWAVE OVER EASTERN TEXAS HAS MADE THE TURN TO THE NORTHEAST...AND WILL BE MOVING THROUGH THE CENTRAL GREAT LAKES LATE TOMORROW. THIS SHORTWAVE WILL DELIVER A NICE SURGE OF GULF MOISTURE TO LOWER MICHIGAN TOMORROW...RESULTING IN OVERRUNNING RAINFALL. 12Z NAM/GFS 295-290 K ISENTROPIC ANALYSIS SHOWING VARYING LIFT THROUGHOUT THE DAY...MAKING THE TIMING OF RAINFALL A LITTLE DIFFICULT. EVEN WHEN THE LIFT/FORCING IS LACKING...WILL LIKELY SEE SOME DRIZZLE WITH 40+ DEW POINTS RIDING OVER THE SNOWCOVER HERE IN SOUTHEAST MICHIGAN. THUS...OCCASIONAL RAIN AND FOG SHOULD COVER TOMORROW JUST FINE. HAVE NOTED THE ELEVATED THUNDERSTORMS ACROSS SOUTHEAST MISSOURI EARLY THIS AFTERNOON. 12Z NAM DOES INDICATE THE SHOWALTER INDEX APPROACHING ZERO BY 12Z SUNDAY ACROSS SOUTHERN LOWER MICHIGAN. HOWEVER...WITH THE MAIN LOW LEVEL JET WEST OF THE REGION...WILL KEEP THE MENTION OF THUNDERSTORMS OUT...IN LINE WITH THE DAY 1 OUTLOOK ISSUED AT 1630Z. FOLLOWED GFS MOS GUIDANCE FOR TEMPS TOMORROW. HOWEVER...TONIGHT IS A DIFFERENT STORY. HAVE GONE 3-6 DEGREES COLDER THAN GUIDANCE. WITH LIGHT WINDS AND PARTLY CLOUDY SKIES THIS EVENING...TEMPS SHOULD DIVE QUICKLY WITH SNOW COVER AND DEW POINTS STILL HOVERING IN THE MID TEENS TO LOWER 20S. 12Z NAM INDICATING 3Z SUNDAY TEMPS IN THE LOWER 20S ACROSS THE NORTH HALF OF THE CWA WHICH SEEMS REASONABLE... ESPECIALLY WITH TEMPS STILL IN THE UPPER 20S AS OF MID AFTERNOON. 12Z RUC13 IS EVEN FORECASTING SURFACE TEMPS IN THE TEENS OVER THE THUMB REGION. THAT SHOULD NOT HAPPEN UNLESS SKIES ARE CLEAR THIS EVENING...WHICH IS NOT IN THE FORECAST DUE TO WARM ADVECTION HIGH CLOUDS STREAMING IN FROM THE WESTERN GREAT LAKES. THINKING TEMPS WILL BE JUST ABOVE FREEZING WHEN RAIN ARRIVES TOMORROW MORNING ACROSS THE NORTH HALF...THUS NO MENTION OF FREEZING RAIN. WARM RAIN DROPS (850 MB TEMPS OF 5 C BY 12Z SUNDAY ACROSS NORTHERN THIRD OF CWA PER BLEND OF NAM/GFS) WITH A SURFACE TEMP OF 32 DEGREES SHOULD NOT CAUSE FREEZING ON CONTACT. NOT TO MENTION SOIL TEMPS ARE STILL ABOVE FREEZING UNDERNEATH THE SNOW. && .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY OVERALL FORECAST CHALLENGES REMAIN THE SAME AS STRONG STORM SYSTEM WRAPS UP THE WEST...FIRST BRINGING MUCH MILDER AIR IN LOWER MICHIGAN EARLY THIS WEEK AS IT FORCES A WARM FRONT NORTH OF THE AREA SUNDAY. THEREAFTER...COLD/OCCLUDED FRONT PROGRESSES THROUGH THE AREA MONDAY WITH THE ATMOSPHERE...IN GENERAL...STEADILY COOLING THE REMAINDER OF THE WEEK (BEFORE ANOTHER SYSTEM RACING ACROSS THE NORTHERN TIER OF THE CONUS BRINGS SOME BRIEF MODIFICATION LATE IN THE FORECAST). RAIN STILL LOOKS TO BE A GOOD BET ON MONDAY/MONDAY EVENING AS COLD FRONT SLOWLY PUSHES THROUGH THE AREA. THERE IS STILL SOME QUESTION AS TO WHETHER THERE WILL BE ANY THUNDER. VERY LITTLE INSTABILITY IS PROGGED...AND FORCING/CONVERGENCE ALONG THE FRONT WILL NOT BE GREAT GIVEN FACT THAT OVERALL FLOW IS PARALLEL TO THE FRONT. THIS LEAVES THE DYNAMIC LIFT FROM THE SYSTEM...WHICH WILL BE DECENT...BUT WITH THE CORE OF THE STORM SO FAR WEST...NOT GREAT EITHER. GIVEN THE FACT THAT A LOT OF THE "INGREDIENTS" ARE MISSING/LACKING...WILL CONTINUE WITH JUST RAIN LIKELY AND NO THUNDER MENTION. DID ADJUST THE TIMING AS PROGRESSION OF THE FRONT IS SLOWER AND RAIN APPEARS TO BE A GOOD BET INTO MONDAY EVENING (AND LESS OF A LIKELIHOOD ON MONDAY MORNING AS WELL). THEREAFTER...THE TRANSITION FROM RAIN TO SNOW BECOMES THE ISSUE AS COLDER AIR FILTERS IN MONDAY NIGHT AND TUESDAY...ALTHOUGH INTENSITY BY THAT TIME WILL BE VERY LIGHT PRECIPITATION (MORE SHOWERY-TYPE). WILL ADJUST TIMING OF -RASN MIX TO TUESDAY MORNING AND ALL -SHSN BY TUESDAY AFTERNOON AFTER COLLABORATION THIS AFTERNOON. PATTERN REMAINS LARGELY UNSETTLED IN COLD UPPER TROF FOR THE REST OF THE FORECAST. WILL ADJUST THE PERIOD WEDNESDAY/WEDNESDAY NIGHT TO DENOTE A LULL IN THE SNOW SHOWERS WITH JUST A FLURRY MENTION...AND THEN BRING THE CHANCE OF MEASURABLE LIGHT SNOW BACK THURSDAY AND MORE OR LESS INTO THE WEEKEND AS NEXT SYSTEM SLIDES INTO THE LAKES REGION. VERY LITTLE CONFIDENCE IN HOW TO HANDLE DAYS 5-7. SEEMS THE BETTER CHANCE OF LIGHT SNOW WILL COME IN THE THURSDAY/FRIDAY AREA GIVEN TIMING OF THE PACIFIC SYSTEM THAT RIDES INTO THE AREA...AND THEN A BRIEF QUIET PERIOD HEADING INTO NEXT WEEKEND. THE PROBLEM IS THAT THE ERRORS IN THIS PATTERN COULD EASILY CHANGE THE TIMING OF THE SYSTEM (AND SUBSEQUENT ONES) BY A SOLID DAY. WILL TRY NOT TO GET TOO CUTE WITH THE FORECAST AT THIS TIME. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...SMALL CRAFT ADVISORY....LATE SUNDAY AFTERNOON THROUGH LATE TUESDAY NIGHT. NEARSHORE WATERS FROM HARBOR BEACH TO PORT HURON AND FOR SAGINAW BAY...SMALL CRAFT ADVISORY...SUNDAY EVENING THROUGH LATE TUESDAY NIGHT. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....DG AVIATION/UPDATE.....CONSIDINE YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 245 AM EST SUN NOV 27 2005 .SHORT TERM (TODAY THROUGH TUESDAY NIGHT)... TODAY THROUGH MONDAY: HEALTHY STRIP OF CONVECTION IS PUSHING INTO ALABAMA THIS MORNING WITH IMPRESSIVE GRAVITY WAVES SHOWING UP ON IR SATELLITE IMAGERY. HIGH CLOUDS CONTINUE TO STREAM INTO NC FROM THE SOUTHWEST BUT THE DENSER OVERCAST OF MID AND LOWER LEVEL CLOUDS ARE ON OUR DOORSTEP. SHOWERS GENERATED BY 850 MB MOISTURE FLUX CONVERGENCE ATTENDING THE NORTHEASTWARD MOVING COASTAL FRONT HAVE MOVED ONSHORE OVER COASTAL SC... AND THE RUC/NAM/GFS ALL AGREE ON QUICKLY INCREASING ISENTROPIC UPGLIDE TODAY ON THE 290-295 K SURFACES... WHILE THE APPROACH OF THE UPPER LEVEL TROUGH AND SUBTROPICAL JET FROM THE SOUTHWEST INCREASES UPPER DIVERGENCE AND MOISTURE INFLOW ALOFT WITH MINOR AMOUNTS OF MID LEVEL POSITIVE VORTICITY ADVECTION. HAVE BROUGHT IN CHANCE POPS ACROSS THE SOUTH LATER THIS MORNING THROUGH MIDDAY... THEN WILL HAVE A PERIOD OF LIKELY POPS THIS AFTERNOON AS SKIES GO MOSTLY CLOUDY EVERYWHERE. GFS RAINFALL PATTERN LOOKS A BIT MORE REALISTIC THAN THE NAM WHICH GRABS ONTO SOME 850 MB CONVERGENCE IN EASTERN NC AND FOCUSES AN INORDINATE AMOUNT OF RAIN THERE. DO ANTICIPATE QPF TO BE LESS THAN MODEL PREDICTIONS DUE TO THE GULF COAST CONVECTION WHICH COULD INDUCE WEAK DOWNSTREAM RIDGING OVER NC THIS AFTERNOON. LITTLE CHANGE IS NEEDED TO CURRENT HIGHS WITH NORTHWEST CWA... WHERE THE WEAK SURFACE-BASED STABLE POOL WILL BE THE LAST TO GO... TOPPING OUT AT JUST 50-52 WITH READINGS NEAR 60 IN THE SOUTHWEST CWA. WITH THE EXIT OF THE UPPER JET AND A LOSS OF ANY SUBSTANTIAL FORCING... PLUS WITH CENTRAL NC EXPECTED TO GET MOSTLY INTO THE WARM SECTOR (EXCEPT FOR MAYBE THE TRIAD AREA) WITH BRIEF MID LEVEL SHORTWAVE RIDGING... SHOWERS SHOULD DECREASE TO SCATTERED (WEST) TO ISOLATED (EAST) TONIGHT AND CONTINUE THROUGH MONDAY. DIFFUSE ISENTROPIC UPGLIDE HANGS ON SO CONSIDERABLE CLOUDINESS IS LIKELY BUT UPPER LEVELS SHOULD DRY OUT BETWEEN TROUGHS AS NOTED UPSTREAM ON THE 700 & 500 MB UPPER AIR ANALYSES. EXPECT AREAS OF FOG TO DEVELOP OVERNIGHT WITH LIGHT SOUTHEAST WINDS. CURRENT VERY MILD LOWS IN THE MID 40S TO LOWER 50S LOOK GOOD AND AGREE WITH AVERAGE OF LATEST MOS GUIDANCE. HIGHS 61-72 MONDAY. TUESDAY: THE NEXT ROUND OF SHOWERS AND SCATTERED THUNDERSTORMS APPEARS IMMINENT WITH ALL MODEL PARAMETERS POINTING TO DEEP MOISTURE AND SUFFICIENT FORCING FROM THE LEFT ENTRANCE REGION OF THE UPPER JET ON THE EAST SIDE OF THE MID LEVEL VORTEX LIFTING ACROSS THE U.P. OF MICHIGAN TOWARD JAMES BAY. WILL HANG ONTO CURRENT CATEGORICAL POPS AS AT LEAST SOME RAINFALL LOOKS INESCAPABLE GIVEN THIS AMOUNT OF LOW LEVEL MOISTURE INFLUX. LOWS 55-60 AND HIGHS 64-72. -GIH && .LONG TERM (WEDNESDAY THROUGH SATURDAY)... NO SIGNIFICANT CHANGES TO THE CURRENT DRY AND MOSTLY CLEAR TO PARTLY CLOUDY FORECAST WITH PREVAILING BROAD CYCLONIC MID LEVEL FLOW THROUGH THE PERIOD. A DEEP UPPER VORTEX WOBBLES FROM MICHIGAN INTO EASTERN CANADA KEEPING MINOR INEFFECTUAL PERTURBATIONS PASSING THROUGH NC WITH A DRY WESTERLY BOUNDARY LAYER FLOW. LOW LEVEL THICKNESSES OFF THE 00Z/27 GFS DROP TO MORE THAN 50 M BELOW NORMAL FOR FRIDAY/SATURDAY WHICH WOULD TRANSLATE TO HIGHS IN THE 40S TO AROUND 50... NOT FAR OFF CURRENT FORECAST TEMPS. -GIH && .AVIATION... WEAK ISENTROPIC LIFT WILL ADVECT ATLANTIC MARITIME MOISTURE LATE THIS MORNING AND INTO THE EARLY AFTERNOON. AS A RESULT...CEILINGS WILL LOWER TO MVFR/IFR AND LIGHT RAIN WILL EXPAND FROM SOUTH TO NORTH ACROSS THE FORECAST AREA. LOWER MISS VALLEY S/W TROUGH WILL APPROACH FROM THE SOUTHWEST AFTER 18Z...BRINGING A SECONDARY FLUX OF MOISTURE AND PRECIP FROM 18 TO 00Z. RAIN SHOULD END FROM SOUTH TO NORTH AS S/W TROUGH MOVES NORTH OF THE AREA ~06Z...HOWEVER IFR/LIFR CEILINGS WILL REMAIN IN PLACE AS 1000-850 S/SE FLOW CONTINUES. -BL && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...LOCKLEAR nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 1124 PM EST SAT NOV 26 2005 .SHORT TERM (REST OF TONIGHT)... CURRENT TEMPS ARE ALREADY RUNNING NEAR OR LOWER THAN OUR FORECAST LOWS MAINLY ACROSS THE SOUTHERN PORTIONS OF THE COUNTY WARNING AREA... AND DEWPOINTS ARE ALSO RUNNING A LITTLE LOWER THAN FORECAST VALUES. HAVE SENT A QUICK UPDATE TO GRAPHICAL AND TEXT PRODUCTS. && .PREVIOUS DISCUSSION... (ISSUED 806 PM EST SAT NOV 26 2005) SHORT TERM (REST OF TONIGHT)... CIRRUS MOVING INTO FORECAST AREA BUT THINNING AS IT PUSHES INTO THE UPPER RIDGE. OVERNIGHT THE RIDGE MOVES EAST AND EXPECT AN INCREASE IN OPAQUE CIRRUS LATE...BUT OVERALL THE REST OF THE NIGHT SHOULD BE PARTLY CLOUDY ON AVERAGE. 18Z GFS SEEMS TO BE VERIFYING BEST WITH AREA OF LESSER ENHANCED CLOUDS SHOWING UP AS A RELATIVE MIN OF RH ON UPPER-LEVEL RH PROG AND THIS RELATIVE MINIMUM IS FORECAST BY THAT MODEL TO PUSH INTO CENTRAL NORTH CAROLINA LATE. AGAIN...PARTLY CLOUDY THE RULE OVERNIGHT...ALTHOUGH SOME AREAS SHOULD BECOME MOSTLY CLOUDY LATE PARTICULARLY WEST AND FAR SOUTHERN ZONES. BROAD SPECTRUM OF TEMPERATURES OVER CENTRAL NORTH CAROLINA WITH COLDEST READINGS GENERALLY NORTH AND NORTHEAST OF THE TRIANGLE WHERE OBSERVATIONS AND MSAS SHOW DEW POINTS BEING THE LOWEST. HAVE LOWERED TEMPERATURES MOST ZONES FOR THE OVERNIGHT HOURS...ESPECIALLY TOWARD THE NORTHEAST WHERE READINGS DURING MID EVENING WERE CREEPING CLOSE TO FORECAST MINS. ONSET OF CIRRUS AND SLOWLY INCREASING DEW POINTS SHOULD KEEP TEMPERATURES FROM FALLING TOO FAR TOO FAST...BUT HAD TO BREAK OUT LEE AND JOHNSTON COUNTIES BECAUSE OF LOCAL OBSERVATIONS SHOWING COOL READINGS. DEW POINTS THERE ALREADY APPROACHING 30 OR BETTER AND DROP SHOULD BE SLOW FOR THE REST OF THE NIGHT. GRIDDED AND WORDED FORECAST UPDATES ISSUED. THANKS TO GSP AND AKQ FOR EVENING COORDINATION. PREVIOUS DISCUSSION... (ISSUED 246 PM EST SAT NOV 26 2005) SHORT TERM (TONIGHT THROUGH TUESDAY)... 12Z RAOB ANALYSIS SHOWED GOOD MOISTURE COMING NORTH AT 850MB OUT OF THE WESTERN GULF AHEAD OF THE UPPER TROUGH OVER THE SOUTHERN PLAINS. SUBTROPICAL JET EXISTED FROM THE SOUTHERN PLAINS INTO THE CAROLINAS WITH GOOD DIFFLUENCE OVER THE WESTERN GULF ON WATER VAPOR IMAGERY. HIGH CLOUDS HAVE DEVELOPED AND THICKENED DURING THE AFTERNOON PARTICULARLY OVER SOUTHERN ZONES...ALTHOUGH VISIBLE AND IR IMAGES SHOW CONSIDERABLE THINNING OFF TOWARD THE WEST. THE RUC HIGH-LEVEL RH FIELDS SUGGEST CIRRUS SHOULD DIMINISH SOME THIS EVENING BEFORE THE NAM AND GFS SPREAD HIGH AND SOME MID-LEVEL CLOUDS BACK IN OVERNIGHT. UPPER RIDGE MOVES THROUGH CENTRAL NORTH CAROLINA EARLY SUNDAY WITH GOOD DIFFLUENCE IN ITS WAKE. BOTH THE NAM AND THE GFS SUGGEST INCREASING LIFT AND MOISTURE BY 18Z SUNDAY WITH SHORTWAVES AT 500MB AND 700MB MOVING ACROSS THE AREA SUNDAY AFTERNOON. NIL LOW-LEVEL CONVERGENCE SO ALL LIFT IS ISENTROPIC...AND THERE IS SOME CONCERN THAT JET DYNAMICS FROM FLORIDA ACROSS GEORGIA WILL RESULT IN MORE PRECIPITATION THERE VERSUS AREAS FARTHER NORTH SUNDAY AFTERNOON. WILL LIMIT POPS TO HIGH CHANCE FOR NOW...ALTHOUGH ANTICIPATE AT LEAST AREAS OF VERY LIGHT RAIN SUNDAY AFTERNOON AS MID-LEVELS MOISTEN WITH THE ISENTROPIC LIFT. WITH INCREASING MOISTURE AND SURFACE RIDGING REMAINING INTACT WARMING SHOULD BE LIMITED SUNDAY AND HAVE LOWERED MAXES A CATEGORY OR TWO. MODEL SOUNDINGS ALSO SUPPORT THIS WITH STRONG LOW-LEVEL INVERSION IN PLACE. DIFFICULT PART OF THE FORECAST IS LATER SUNDAY NIGHT THROUGH MONDAY NIGHT...DUE TO DIFFERENCES IN THE GFS VERSUS THE NAM. THE LATTER IS MUCH DRIER PARTICULARLY TOWARD THE COASTAL PLAIN DUE TO ITS HIGHER AMPLITUDE RIDGE LOCATED CLOSER TO THE ATLANTIC COAST. AS A RESULT...SUBSIDENCE IS HIGHER ON THE NAM AND DEEPER MOISTURE REMAINS SHUNTED WELL WEST...EVEN TO A LARGE DEGREE WEST OF THE TRIAD. BOTH THE NAM AND THE GFS FORECAST WEAK UVV PARTICULARLY IN WESTERN ZONES MONDAY...AND PLAN TO DEFER SLIGHTLY TO THE GFS DUE TO THE STRENGTH OF THE UPPER TROUGH OVER THE SOUTHERN PLAINS AND THE AMOUNT OF MOISTURE MOVING NORTH ON THE LATEST RAOB ANALYSIS OVER THE GULF. WITH EXACT RIDGE POSITION UNCERTAIN...PRUDENT TO CONTINUE CHANCE POPS WEST TO SLIGHT CHANCE EAST THOUGH FEEL AT THIS POINT PERIODS OF PRECIPITATION SHOULD BE LIMITED WITH AMOUNTS LIGHT. GFS HAS TRENDED SLOWER FROM ITS 00Z AND EVEN 06Z RUNS WITH THE EASTWARD PROGRESSION OF THE SURFACE FRONT TUESDAY AND TUESDAY NIGHT...IN PART COURTESY OF WAVES ALONG THE FRONT AND ITS POSITIVE TILT IN THE SOUTHWEST FLOW ALOFT. THIS COULD RESULT IN PERIODS OF MODERATE RAINFALL ALONG THE FRONT WITH GOOD LIFT FORECAST BY BOTH THE NAM AND THE GFS. JET SUPPORT AT 300MB AND 500MB REMAINS BEST WEST AND NORTH OF THE FORECAST AREA...BUT LOW-LEVEL WIND FIELDS ARE STRONG...40KTS OR GREATER ABOVE 925MB. INSTABILITY SHOULD BE LIMITED TUESDAY DUE TO CLOUDS...HOWEVER...MEAGER BREAKS IN WARM AND MOIST AIR MASS COULD RESULT IN MARGINAL INSTABILITY...ENOUGH FOR THUNDER. MODEL SOUNDINGS ARE NOT IMPRESSIVE REGARDING INSTABILITY... AND LIFTED INDICES BOTH FROM THE NAM AND THE GFS EEK EVER SO SLIGHTLY BELOW ZERO TUESDAY AFTERNOON WITH CAPE FORECAST BETWEEN 100 AND 500J/KG. HAVE DECIDED TO RAISE POPS TUESDAY GIVEN CONSENSUS OF FRONTAL LOCATION FROM THE NAM AND GFS...WITH HIGHEST POPS WEST. LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)... MOIST...SOUTHERLY FLOW AND DECENT LIFT ALONG AND AHEAD OF THE FRONT...ALONG WITH THE SURFACE WAVES...RESULT IN GOOD CHANCES FOR SHOWERS CONTINUING FOR A LARGE PART OF TUESDAY NIGHT WITH THE HIGHEST POPS TOWARD THE I-95 CORRIDOR. WILL LIMIT THUNDER CHANCES FOR THE NIGHTTIME HOURS TUESDAY CENTRAL AND EAST IMMEDIATELY ALONG THE FRONT. CONSENSUS OF GUIDANCE...AND EVEN THE SLOWER GFS...HAS THE COLD FRONT EAST OF CENTRAL NORTH CAROLINA BY 12Z WEDNESDAY AND ANTICIPATE DRY CONDITIONS BY SUNRISE WEDNESDAY WITH DIMINISHING CLOUDS WEDNESDAY MORNING. SUBSIDENCE WILL BE THE RULE FOR THE REST OF THE WEEK AFTER TUESDAY NIGHT. SURFACE RIDGING WILL PREVAIL SOUTH ACROSS THE EASTERN GULF OF MEXICO...AND THOUGH ANOTHER COLD FRONT SHOULD PUSH ACROSS THE STATE LATE THURSDAY INTO FRIDAY AS ANOTHER UPPER TROUGH MOVES THROUGH...SURFACE MOISTURE SHOULD BE LIMITED AND THE GFS KEEPS MOST OF THE ENERGY NORTH OF THE STATE. ALTHOUGH THE DGEX IS MORE AMPLIFIED WITH THE UPPER TROUGH AND FORECASTS DECENT MID-LEVEL VORTICITY TO MOVE OVER CENTRAL NORTH CAROLINA FRIDAY WITH SLIGHTLY MORE MOISTURE...ITS QPF REMAINS DRY. ENSEMBLE MOS POPS ARE ALMOST ALL BELOW CLIMATOLOGY SO WILL MAINTAIN THE DRY FORECAST FOR THE BULK OF THE LONG-TERM PERIOD WITH TEMPERATURES WITHIN A FEW DEGREES OF SEASONAL NORMS. AVIATION... THIN BKN CIRRUS SPREADING OVER CENTRAL NC THIS AFTERNOON WILL REMAIN AROUND 25KFT THROUGH MIDNIGHT. MODEL RUNS THIS AFTERNOON HAVE BECOME MORE AGGRESSIVE WITH MOISTURE INCREASING IN THE LOWER LEVELS SUNDAY MORNING. THE NAM IS FASTER AT INCREASING LOW CLOUDS EARLY SUNDAY MORNING AND THIS FORECAST LEANS MORE TOWARDS THE SLOWER GFS. BOTH MODELS SHOW STRONG OVERRUNNING SETTING UP BY MID TO LATE MORNING WITH A LOW LEVEL JET OF 30KT. EXPECT A RAPID INCREASE OF MID AND LOW CLOUDS SUNDAY MORNING. MVFR CONDITIONS SHOULD DEVELOP FROM SUNRISE THROUGH MID MORNING. CEILINGS WILL CONTINUE TO LOWER THROUGH THE LATE MORNING HOURS APPROACHING VFR CONDITIONS BY AFTERNOON. OVERRUNNING LIFT WILL ALSO GENERATE SOME PRECIP FROM LATE MORNING INTO THE AFTERNOON RESULTING IN LIMITED VISIBILITIES FOR EARLY AND MID AFTERNOON. EXPECT MVFR TO IFR CONDITIONS TO PERSIST THROUGH MUCH OF SUNDAY AFTERNOON. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HARTFIELD nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 1015 PM CST SAT NOV 26 2005 .UPDATE...HAVE EXPANDED THE FREEZING RAIN ADVISORY INTO CNTRL WISCONSIN AND EXTENDED THE END TIME FOR A FEW OF THE NORTHERN COUNTIES. LATEST MODEL RUNS SHOW LIGHT FREEZING RAIN OR RAIN DEVELOPING OVER C/EC WI BETWEEN 09-12Z...WITH ENOUGH LLVL MOISTENING FOR FREEZING DRIZZLE OVER N WI. THE RUC HAD A GOOD HANDLE ON SFC TEMPS AT 03Z...AND SHOWS TEMPS REMAINING BLO FREEZING ACROSS ALL BUT THE FOX VALLEY/LKSHR AREAS LATE TONIGHT INTO SUN MORNING. DEPT OF TRANSPORTATION ROAD TEMP SENSORS SHOW ROAD SFCS WELL BLO FREEZING ACROSS THE ENTIRE FCST AREA...NOT SURPRISING SINCE MOST OF THE AREA HAS BEEN WELL BLO FREEZING SINCE LAST WEDS NGT. EXPECT ROAD SFCS TO SLOWLY RESPOND TO WARMING SFC TEMPS...BUT IT'S LIKELY THAT LOCAL FREEZING PRECIP WILL CONTINUE FOR SEVERAL HOURS AFTER SFC TEMPS RISE ABOVE FREEZING. ALTHOUGH WAUSHARA COUNTY AND THE FOX VALLEY HAVE NOT BEEN ADDED TO THE ADVY ATTM...NEXT SHIFT WILL NEED TO MONITOR THESE AREAS CLOSELY...AS THE POTENTIAL EXISTS FOR SOME ICING. HAVE KEPT A MENTION OF RAIN OR FREEZING RAIN IN THE FCST FOR THESE AREAS LATE TONIGHT. UPDATED ADVISORY STATEMENT AND ZONE FORECASTS HAVE BEEN SENT. GRIDDED FCST WILL BE UPDATED SHORTLY. DISCUSSION FROM PREVIOUS SHIFT... .SHORT TERM...SATURDAY NIGHT THROUGH SUNDAY. FORECAST CHALLENGE IS POTENTIAL FOR FREEZING DRIZZLE OVERNIGHT INTO SUNDAY MORNING ACROSS PARTS OF CWA. SOUTHEAST WINDS AT SURFACE ARE EXPECTED TO BRING LOW-LEVEL MOISTURE FROM LAKE MICHIGAN OVER LAND AREAS WHICH HAVE BEEN BELOW FREEZING FOR A FEW DAYS... CAUSING FREEZING DRIZZLE TO DEVELOP. THE FREEZING DRIZZLE IS EXPECXTED TO PERSIST INTO LATE SUNDAY MORNING ACROSS THE FAR NORTH. SYNOPTIC SCALE RAIN WILL FOLLOW ON SUNDAY WITH THE EXPECTATION THAT LOW LEVELS WILL HAVE WARMED SUFFICIENTLY TO ABOVE FREEZING...EVEN ACROSS THE FAR NORTH. KEPT TEMPERATURES AND WINDS FROM PREVIOUS MAIN FORECAST. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. WITH MOST OF THE ATTENTION FOCUSED ON THE SHORT TERM...THE EXIT OF THE APPROACHING SYSTEM WAS THE MAIN CONCERN DURING THIS PERIOD. LITTLE...IF ANYTHING...WAS CHANGED FROM THE PREVIOUS FORECAST. LIQUID PCPN CAN BE EXPECTED THROUGH MONDAY. THEN COLD AIR WRAPS AROUND THE LOW AND BRINGS A CHANCE OF SNOW BACK THE THE NORTHWEST 2/3 OF THE AREA MONDAY EVENING...AND THE ENTIRE AREA BY 12Z TUE. A CHANCE OF SNOW SHOWERS REMAINS FOR TUE...AND FLURRIES ARE POSSIBLE TUE EVENING AS THE SYSTEM PULLS AWAY WISCONSIN. && .GRB WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY 3 AM TO 11 AM SUNDAY WIZ005-010>013-018-019-021 FREEZING RAIN ADVISORY 3 AM TO 9 AM SUNDAY WIZ020-030-031-035>037-073-074- && $$ KIECKBUSCH WEATHER.GOV/GREENBAY wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 820 AM MST SUN NOV 27 2005 .SYNOPSIS...A STRONG LOW PRESSURE SYSTEM OVER COLORADO WILL CONTINUE TO PRODUCE GUSTY WINDS AND FEED MUCH COLDER AIR TO THE REGION. DRY CONDITIONS WITH BELOW NORMAL TEMPERATURES ARE EXPECTED FOR THE START OF THE WEEK...WITH A SLOW WARMING TREND UNDER WEAK HIGH PRESSURE FOR THE SECOND HALF OF THE WEEK. && .DISCUSSION...HAVE RUN OUT AN UPDATE TO HANDLE SHORT-TERM TRENDS, BUT FOR THE MOST PART THE FORECAST AND CURRENT HEADLINES ARE HANDING THIS HIGHLY DYNAMIC SITUATION QUITE WELL. POWERHOUSE 140KT JET EXTENDING DOWN TO 400MB IS KNIFING ACROSS NE AZ INTO INTO NM. POTENTIAL VORTICITY CROSS SECTIONS SHOW THE ATTENDING TROPOPAUSE FOLD ALL THE WAY DOWN NEAR THE SURFACE OVER SE AZ. DEWPOINTS ARE CRASHING AS EXPECTED WITH RUC AND LAPS BOTH SHOWING SYNOPTIC DOWNWARD VERTICAL MOTION ON THE ORDER OF 15 MICROBARS/SEC. 12Z KTUS SOUNDING SHOWED 90KT WINDS JUST ABOVE THE LOWERING SUBSIDENCE INVERSION /AT ABOUT 14KFT/. AS EXPECTED BY OUR PREDECESSORS, VALLEY WINDS FELL OFF A BIT JUST BEFORE SUNRISE DUE TO A BIT OF DECOUPLING, BUT THEY'RE ALREADY STARTING TO PICK UP AGAIN. RAWS SITES ARE CONFIRMING GUST POTENTIAL TO 50MPH IN THE E CWA, MOST LIKELY AROUND NOON BEFORE THE TIGHTEST GRADIENT SHIFTS E AND THE STRONG LOW LEVEL COLD ADVECTION STARTS TO SUPPRESS MIXING. THE SNOW FORECAST IN ZONE 19 WORKED OUT WITH HANNAGAN MEADOW REPORTING 2 INCHES A SHORT TIME AGO. THE FORECAST UPDATE INCLUDES A MENTION OF BLOWING DUST IN ZONES 30/35, A CHANGE TO JUST FLURRIES IN ZONE 19 AS THE SUBSIDENCE INVERSION CONTINUES TO LOWER, AND SLIGHTLY HIGHER WINDS FROM KTUS W. HAVE ALREADY TALKED TO AZ DPS AND GRAHAM/COCHISE COUNTIES ABOUT POTENTIAL FOR MORE SERIOUS BLOWING DUST. WE'LL BE KEEPING CLOSE TABS ON THAT BETWEEN KTUS AND THE NM LINE, ESPECIALLY SINCE THIS IS A BIG HOLIDAY TRAVEL DAY ON I-10. NO CHANGES IN THE OUT PERIODS. WE'RE LIKELY TO SEE AT LEAST A DECENT FREEZE IN KTUS METRO TONIGHT, EVEN IF THE WINDS DO STAY UP A BIT THIS EVENING. LONG WARNING DURATION IS BECAUSE SHELTERED AREAS ARE LIKELY TO SEE A GOOD 6-8HRS OF <32F TEMPS AND PERHAPS LOWS IN THE MID 20S. WINTER HAS ARRIVED. && .FIRE WEATHER...WINDS WILL CONTINUE TO BE A PROBLEM TODAY E OF KTUS WITH WEST TO NORTHWEST WINDS RUNNING 25 TO 35 MPH WITH GUSTS TO 50. DRY CONDITIONS WILL CONTINUE...AND SOME LOCATIONS WILL FALL BELOW 15 PERCENT MINIMUM RH VALUES FOR A TIME THIS AFTERNOON. SINCE THERE IS ALSO A HIGH FIRE DANGER RATING...A RED FLAG WARNING HAS BEEN ISSUED. && .AVIATION...TAF AND TWEBS ADEQUATELY COVER ALL SIGNIFICANT WEATHER AT KTUS. && .TWC WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY THROUGH 5 PM FOR ZONES 019/030/035. RED FLAG WARNING THIS AFTERNOON AND EARLY EVENING FOR EASTERN FIRE WEATHER ZONE 148. FREEZE WARNING TONIGHT FOR ZONES 029/032/033. && $$ PYTLAK WEATHER.GOV/TUCSON az AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LITTLE ROCK AR 958 AM CST SUN NOV 27 2005 .UPDATE... WILL GET OUT AN UPDATE TO GET RID OF THE MORNING SHOWERS. A LOT OF LOW CLOUDS ARE ACROSS THE AREA THIS MORNING BUT NO PRECIP IS INDICATED ON KLZK RADAR. UPDATED TEMPERATURES IN THE GRIDS BASED ON CURRENT OBSERVATIONS AND TRENDS. MAX TEMPS LOOK FINE AT THIS POINT. COLD FRONT STILL IN CENTRAL KANSAS AND WESTERN OKLAHOMA MOVING EAST. AS THE LOW APPROACHES WINDS WILL INCREASE ACROSS THE AREA AND THE LAKE WIND ADVISORY WILL CONTINUE. MODERATE RISK OF SEVERE WEATHER CONTINUES ACROSS THE AREA THIS AFTERNOON AND EVENING. INCLUDED MENTION OF SEVERE WEATHER IN THE AFTERNOON PERIOD AS STORMS MAY GENERATE BY LATE AFTERNOON...22Z-23Z. && .PREV DISCUSSION.../ISSUED 315 AM CST SUN NOV 27 2005/ SHORT TERM...SUNDAY THROUGH WEDNESDAY NIGHT PRECIPITATION TOOK A WHILE TO MAKE IT INTO THE CWA SATURDAY AND LOOKING BACK...IT APPEARS THE GFS ACTUALLY HAD THE BETTER TIMING. WITH OVERRRUNING EVENT WRAPPING UP EARLY THIS MORNING...ITS TIME TO CONCENTRATE ON THE DEVELOPING CONVECTIVE EVENT SLATED FOR LATER THIS AFTERNOON AND TONIGHT. WHILE NAM AND GFS ARE BOTH DEEPER AND SLOWER WITH THE SYSTEM TONIGHT...STILL LIKE THE GFS SOLUTION. BASED ON THE CONTINUITY OF THE GFS AND ITS HANDLING OF THE SYSTEM MOVING THROUGH NOW...SEE NO REASON TO DEVIATE AWAY FROM IT. OVERRUNNING/WARM AIR ADVECTION PRECIPITATION CONTINUING TO MOVE TOWARDS THE NORTH AS WEAKENING MID LEVEL WAVE OVER THE CENTRAL GULF COAST LIFTS OFF TO THE NORTHEAST. MAJORITY OF THE PRECIPITATION WILL BE OVER BY PRESS TIME BUT WILL STILL HOLD ON TO SOME MINIMAL POPS EARLY OVER THE NORTHEAST PART OF THE CWA AS RUC13 MODEL HOLDS ON TO SOME LIGHT PRECIP THROUGH MID MORNING. MAJORITY OF THE DAY WILL BE DRY AS AREA WILL BE BETWEEN SYSTEMS BUT RAIN CHANCES WILL BE INCREASING ONCE AGAIN THIS AFTERNOON AS NEXT SYSTEM APPROACHES FROM THE WEST. MAJOR PLAYERS STILL SHOWING UP QUITE NICELY ON WATER VAPOR IMAGERY THIS MORNING...MAINLY THE EXITING MID LEVEL WAVE AND THE VIGOROUS UPPER LEVEL SYSTEM CURRENTLY OVER THE ROCKIES. DEEP TROF EVIDENT JUST SOUTH OF THE 4 CORNERS WITH STRONG IMPULSE ROTATING THROUGH ITS BASE ACROSS NORTHERN ARIZONA/NEW MEXICO. SYSTEM STILL LOOSELY ORGANIZED AT THE MOMENT BUT BUT EXPECTED TO QUICKLY INTENSIFY LATER THIS MORNING AS IT LIFTS OUT INTO THE CENTRAL PLAINS. LEE CYCLOGENESIS ALREADY UNDERWAY OVER THE CENTRAL PLAINS. SURFACE LOW ALSO EXPECTED TO DEEPEN RAPIDLY THIS MORNING IN RESPONSE TO THE EXIT REGION OF MID LEVEL JET MOVING THROUGH. SURFACE LOW EXPECTED TO BE IN NORTH CENTRAL OKLAHOMA BY MID DAY AND RACING OFF INTO SOUTHERN IOWA BY MONDAY MORNING. PROJECTED PATH WOULD KEEP AREA IN WARM SECTOR THE ENTIRE DAY WITH SOUTHERLY WINDS PROVIDING GOOD MOISTURE RETURN. GRADIENT BETWEEN SYSTEMS LOOKS PRETTY TIGHT AND WILL HOIST A LAKE WIND ADVISORY FOR THE ENTIRE CWA FOR TODAY. EXPECTING SQUALL LINE TO DEVELOP IN ADVANCE OF THE ATTENDANT COLD FRONT THIS AFTERNOON OVER THE CENTRAL PLAINS WHICH WILL THEN SWEEP THROUGH THE STATE LATE THIS AFTERNOON AND EVENING. STRONG DIFFLUENCE NOTED ALOFT ALONG WITH GOOD SURFACE CONVERGENCE BUT INSTABILITY APPEARS MARGINAL AT BEST RIGHT NOW. HOWEVER...THERE IS SOME CONCERN THAT COULD CHANGE. WIDESPREAD CLOUD COVER TODAY SHOULD KEEP INSTABILITY IN CHECK BUT ANY SIGNIFICANT CLEARING COULD LEAD TO EXPLOSIVE DEVELOPMENT ALONG THE FRONT. BIGGEST THREAT APPEARS TO BE STRAIGHT LINE WINDS WITH FAST MOVING LINE WHICH WILL BE LOCATED NEAR THE MISSISSIPPI RIVER NEAR MIDNIGHT. WILL END THE PCPN ACROSS THE AREA FROM WEST TO EAST SUNDAY EVENING AS FRONT MOVES THROUGH. AFTER SOME BRIEF CLEARING SUNDAY NIGHT/EARLY MONDAY...LARGE SLUG OF MOISTURE WILL ROTATE AROUND THE MAIN LOW MONDAY AFTERNOON THROUGH EARLY TUESDAY AS TROF AXIS PASSES THROUGH. NO PRECIPITATION EXPECTED. TEMPERATURES WILL COOL OF INITIALLY BEHIND THE FRONT WITH STRONGER COLD AIR AIR ADVECTION BEHIND THE PASSAGE OF THE TROF. HIGH PRESSURE WILL BUILD IN FROM THE SOUTHERN PLAINS BY MIDDAY TUESDAY FOR DRY AND COOL CONDITIONS TUESDAY. TEMPERATURES WILL MODERATE WEDNESDAY AS CENTER OF THE HIGH MOVES EAST AND WINDS RETURN TO A SOUTHERLY DIRECTION AND FLOW ALOFT STARTS TO BECOME MORE ZONAL. MAV NUMBERS LOOK PRETTY GOOD BUT WILL GO ABOVE GUIDANCE ON WEDNESDAY. LONG TERM...THURSDAY THROUGH SATURDAY LARGE VORTEX TO OUR NORTHEAST WILL CONTINUE MOVING AWAY FROM THE STATE WHILE RIDGE AMPLIFIES TO OUR WEST. H5 RIDGE WILL BE JUST EAST OF AR BY 00Z SUN...AND IT WILL BE CLOSE TO THE EAST COAST BY SUNDAY MORNING. IN THE MEANTIME...ANOTHER LONG WAVE TROF WILL BE TRAVERSING THE ROCKIES. THE SURFACE PATTERN WILL BEGIN THE PERIOD WITH A COLD FRONT HAVING JUST EXITED THE SOUTHEAST CORNER OF THE STATE. HIGH PRESSURE WILL PUSH DRIER AIR OVER THE STATE FROM THE NORTH...WHILE HOLDING OFF GULF MOISTURE ALONG THE COAST BY 00Z FRIDAY. HIGHER RH VALUES WILL MOVE NORTH THROUGH LA OVERNIGHT INTO FRIDAY MORNING... BUT THEY DO NOT QUITE PUSH INTO THE STATE. I WILL HAVE TO HOLD OFF ANY MENTION OF RAIN UNTIL LATE IN THE DAY SATURDAY. TEMPS WILL BE CLOSE TO NORMAL THURSDAY...AND THEY WILL TAKE A DIP BELOW NORMAL FOR FRIDAY AND SATURDAY. && .LZK WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY UNTIL 6 PM SUNDAY FOR ARZ003-ARZ004-ARZ005- ARZ006-ARZ007-ARZ012-ARZ013-ARZ014-ARZ015-ARZ016-ARZ021-ARZ022- ARZ023-ARZ024-ARZ025-ARZ030-ARZ031-ARZ032-ARZ033-ARZ034-ARZ037- ARZ038-ARZ039-ARZ040-ARZ041-ARZ042-ARZ043-ARZ044-ARZ045-ARZ046- ARZ047-ARZ052-ARZ053-ARZ054-ARZ055-ARZ056-ARZ057-ARZ062-ARZ063- ARZ064-ARZ065-ARZ066-ARZ067-ARZ068-ARZ069. && $$ 51 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 432 AM MST SUN NOV 27 2005 .SHORT TERM... (TODAY AND TONIGHT) MAIN SHORT TERM CONCERNS CONTINUE TO BE EFFECTS OF PASSING SYSTEM. CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATING STRONG 140+ KT JET CORE EXTENDING FROM THE PACIFIC NORTHWEST ACROSS THE SOUTHERN GREAT BASIN AND INTO CENTRAL NEW MEXICO...CARVING OUT A BROAD UPPER TROUGH ACROSS THE NORTHERN AND CENTRAL ROCKIES ATTM. AT THE SFC...1-3MB 3 HRLY PRESSURE FALLS CONTINUING OUT AHEAD OF SYSTEM WITH MSAS DATA INDICATING 989MB LOW ACROSS THE OK PANHANDLE ATTM. REGIONAL RADARS INDICATING ISOLATED TO SCATTERED SHOWERS ACROSS THE CENTRAL AND SW MTS...ALONG WITH DEVELOPING ECHOES ACROSS THE SOUTHEAST PLAINS ATTM. TODAY...MODELS CONTINUE TO BE IN GOOD AGREEMENT ON DEVELOPING VERTICALLY STACKED LOW PRESSURE SYSTEM ACROSS THE OK PANHANDLE THIS MORNING...AS STRONG JET CORE CONTINUES TO MOVE INTO WESTERN TEXAS. THIS SYSTEM THEN CONTINUES TO LIFT OUT ACROSS THE CENTRAL HIGH PLAINS...ALLOWING FOR STRONG CAA TO DEVELOP ACROSS THE EASTERN PLAINS THIS AFTERNOON. IR IMAGERY INDICATING ENHANCED VERTICAL MOTION ACROSS THE PLAINS ATTM...AND HAVE KEPT CHANCE TO LIKELY POPS ACROSS SOUTHEAST COLORADO THIS MORNING...WITH BEST POPS ACROSS THE EASTERN NEW MEXICO BORDER. BEST POPS SPREAD OUT ACROSS THE FAR SE PLAINS THIS AFTERNOON...WITH DEVELOPING DEFORMATION ZONE. GUSTY NORTH TO NORTHWEST WINDS OF 30 TO 40 MPH EXPECTED THIS AFTERNOON ACROSS THE PLAINS AS WELL...WITH STRONG PRESSURE GRADIENT DEVELOPING AS STACKED LOW BEGINS TO MOVE EAST. WITH STRONG CAA...HAVE KEPT TEMPS GENERALLY BELOW GUIDANCE...WITH HIGHS LATE THIS MORNING AND FALLING TEMPS INTO THE AFTERNOON. HAVE DECIDED TO CANCEL SNOW ADVISORY FOR THE CENTRAL AND SW MTS (ZONES 58>60 AND 66)...AS DESPITE GOOD CAA AND INSTABILITY...LIMITED MOISTURE WILL KEEP SNOW AMOUNTS BETWEEN 1 AND 4 INCHES OF FLUFFY SNOW. TONIGHT...VERTICALLY STACKED SYSTEM CONTINUES TO LIFT OUT ACROSS THE CENTRAL HIGH PLAINS...WITH WINDS SLOWLY DIMINISHING FROM WEST TO EAST ACROSS THE THE PLAINS AS PRESSURE GRADIENT BEGINS TO RELAX. WITH COLD AND DRY AIR IN PLACE ACROSS THE PLAINS...WILL SEE CHILLY OVERNIGHT LOWS...THOUGH WINDS WILL KEEP TEMPS FROM DROPPING TOO MUCH. CAA CONTINUES ACROSS THE CENTRAL MTS...THOUGH MOISTURE REMAINS LIMITED AND HAVE KEPT SCATTERED POPS IN PLACE WITH SOME LIGHT ACCUMULATIONS POSSIBLE OVERNIGHT. -MW .LONG TERM... (MONDAY THROUGH SATURDAY) MAIN CHALLENGES ARE CHANCE FOR PRECIPITATION...AND TEMPERATURES IN THE LONG TERM. MONDAY...LOOKS LIKE WINDS WILL STILL BE STRONG OVER THE FAR SOUTHEASTERN PLAINS DURING THE DAY WITH 700MB WINDS STILL OVER 60 KNOTS. GUSTS AT THE SURFACE WILL LIKELY BE AROUND 40 MPH OR INFREQUENTLY HIGHER. COLD AIR ENTRENCHED ACROSS THE CWFA WITH READINGS FROM -7 TO -14 DEGREES AT 700MB. TUESDAY...FLOW FROM THE WEST-NORTHWEST BRINGS IN SOME WARMER AIR ALOFT SO BOOSTED HIGH TEMPERATURES AND KEPT THE SMALL CHANCES FOR SNOW SHOWERS IN THE FAVORED CENTRAL AND SOUTHWEST MOUNTAINS. WEDNESDAY AND THURSDAY...MODELS HINT AT BRINGING IN SOME COOLER AIR...BUT WITH LIMITED MOISTURE...LOOKS LIKE BEST CHANCES FOR MEASURABLE SNOW WILL BE IN THE CENTRAL MOUNTAINS AGAIN. FRIDAY AND SATURDAY...UPPER FLOW TRANSITIONED TO MORE WEST THEN WEST- SOUTHWEST...WHICH WILL BRING IN MILDER AIR AGAIN...AND MAINLY DRY WEATHER...WITH THE EXCEPTION OF THE WESTERN MOUNTAINS. THIS IS IN ADVANCE OF NEXT COLD FRONT WHICH COULD MOVE IN ON SUNDAY. && .PUB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 853 AM EST SUN NOV 27 2005 .DISCUSSION...A SHORT WAVE TROUGH IS LIFTING NEWD ACROSS THE GULF COAST STATES THIS MORNING. A WARM FRONT IS MOVING SLOWLY NWD ACROSS THE NRN GULF. AREA RADARS SHOW AN AREA OF RAIN IN THE REGION OF DPVA AHEAD OF THE SHORT WAVE. THIS AREA ALSO CORRESPONDS TO THE REGION OF MAXIMUM ISENTROPIC ASCENT OVER THE WARM FRONT ON THE 295 K SURFACE PER THE LATEST RUC. LIGHTNING HAS BEEN DIMINISHING STEADILY AS THE PRECIPITATION MOVES INTO A MORE STABLE AIR MASS. HOWEVER...AN ISOLATED TS IS STILL POSSIBLE OVER THE GULF. ANY THAT DO MAKE IT TO THE COAST WILL BE ELEVATED OVER THE STABLE LAYER, SO DESPITE VERY FAVORABLE SHEAR PROFILES, SEVERE WEATHER IS BECOMING LESS OF A CONCERN. THE SHORT WAVE WILL SWEEP QUICKLY EWD TODAY, AND THE ISENTROPIC LIFT WILL WEAKEN WITH TIME. THEREFORE, WE EXPECT HIGHEST POPS THIS MORNING. WE WILL UPDATE THE FORECAST TO ACCOUNT FOR RADAR TRENDS AND TO REMOVE TS OVER INLAND AREAS. && .MARINE...WINDS AND SEAS REMAIN AT ADVISORY LEVELS AT THE OFFSHORE BUOYS S OF THE WARM FRONT. N OF THE BOUNDARY, WINDS ARE LIKELY A BIT LIGHTER. OF COURSE, THERE'S NO DATA IN THIS AREA, BUT JUDGING BY WHAT WE'RE SEEING AT THE COASTAL ASOS STATIONS, THE CAUTION HEADLINE IS LIKELY SUFFICIENT FOR THE NEAR SHORE LEGS. WINDS WILL DIMINISH THIS AFTERNOON, BUT SEAS WILL TAKE A BIT LONGER INTO THIS EVENING TO DROP BELOW ADVISORY CRITERIA. ONSHORE WINDS WILL REMAIN ELEVATED UNTIL COLD FRONTAL PASSAGE ON TUE, AND FOR A BRIEF TIME AFTER THE WIND SHIFT BEFORE, SUBSIDING LATER IN THE WEEK. && .AVIATION...MVFR CIGS AND VSBY SHOULD PREVAIL IN THE RAIN AREA INCLUDING DHN AND PFN THIS MORNING, WITH OCCASIONAL DIPS INTO THE IFR RANGE. TO THE E, MORNING IFR/LIFR CONDITIONS WILL TAKE A BIT LONGER THAN NORMAL TO LIFT TODAY, WITH VSBY IMPROVING FIRST. CIGS WILL EVENTUALLY LIFT TO VFR THIS AFTERNOON AT ALL THE TERMINALS. OVERNIGHT, WE EXPECT A RETURN OF IFR/LIFR CIGS AND MVFR TO IFR VSBY AT THE INLAND TAF SITES, WITH VLIFR CONDITIONS POSSIBLE AT ABY AND VLD. && .FIRE WEATHER...NO CONCERNS UNTIL WED. && .PREV DISCUSSION... 144 AM EST SUN NOV 27 2005 SHORT TERM...AS THE S/W TO THE WEST ROTATES AROUND THE UPR LOW OVER THE CENTRAL CONUS...IT WILL LIFT TO OUR NORTH AND KEEP MOST OF THE ENERGY OUT OF OUR AREA. THIS WILL MOST LIKELY MEAN THAT THE LINE OF SHRA/TSRA WILL START TO DIMINISH BEFORE IT MAKES IT OVER INTO OUR AREA. STILL LOOKING FOR MID-RANGE CHANCE POPS HOWEVER IN OUR WESTERN AND NORTHERN ZONES TODAY...THEN DROPPING TO LOW END CHANCE FOR ALL AREAS TONIGHT. PRETTY CONFIDENT IN LOWERING POPS TONIGHT BUT NEXT QUESTION MARK IS GOING TO BE MONDAY. THE GFS AND NOW ETA HAVE BEEN MVG AN AREA OF TROPICAL MOISTURE NORTH THROUGH THE EASTERN GULF...AND INTO OUR AREA EARLY MONDAY. THIS WOULD CALL FOR AN INCREASE IN POPS ON MONDAY AHEAD OF THE FRONT THAT WILL KEEP POPS IN THE HIGH-END CHANCE TO LIKELY CATEGORY THROUGH TUES. LONG TERM...MODELS HAVE BEEN PRETTY CONSISTENT AND AGREEABLE ON FROPA THE FIRST PART OF TUES. LIKELY POPS THEREFORE MON NIGHT THROUGH TUES MORNING...THEN TAPERING OFF WEST TO EAST BY TUES AFTN. TEMPS WILL DROP BACK TO AROUND NORMAL ON WEDNESDAY THEN REMAIN AT OR BELOW CLIMO THROUGH THE WEEKEND WITH A REINFORCING SHOT OF COOL AND DRY AIR ON FRIDAY. ALTHOUGH THE MEX COULD BE OVER-DOING THE COLD AIR THIS WEEKEND...LOWS SHOULD BE DOWN INTO AT LEAST THE MID 30S BOTH SAT AND SUN. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 75 62 74 63 / 30 30 50 60 PANAMA CITY 75 65 76 63 / 50 30 50 60 DOTHAN 72 60 74 60 / 50 30 60 60 ALBANY 73 60 74 61 / 40 30 50 60 VALDOSTA 76 60 76 62 / 30 30 50 60 CROSS CITY 80 61 77 64 / 20 30 50 60 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...SMALL CRAFT ADVISORY OFFSHORE WATERS. && $$ CURRENT DISCUSSION...WOOL PREVIOUS DISCUSSION...MCNATT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 515 AM CST SUN NOV 27 2005 .DISCUSSION...SIMPLY PUT...MAIN ISSUE IS POTENTIAL FOR SIGNIFICANT WINTER STORM FROM LATE SUNDAY AFTERNOON THRU MONDAY. MODEL OF CHOICE WAS THE UKMET. MOST CONSISTENT THE LAST TWO DAYS AND OTHER OPERATIONAL MODELS (NAM/GFS) HAVE COME ITS DIRECTION. SHARP AND MEANDERING BAROCLINIC BOUNDARY OVER THE CWFA AT THIS TIME. THIS BOUNDARY IS WELL HANDLED BY THE RUC13 SURFACE DEPICTIONS. IT IS FORECAST TO ONLY SLOWLY MOVE EAST THROUGH EARLY AFTERNOON BEFORE GETTING ALONG A BIT QUICKER. UKMET AND NOW MODEL SWEAT POINT TOWARD A MAJOR WINTER STORM POSSIBLE LATER TODAY. FRONTOGENETIC FORCING IS VERY HIGH. SHARP AND POWER-HOUSE JET WILL RESULT IN RAPID DEEPENING OF THE APPROACHING UPPER LEVEL LOW PRESSURE SUNDAY EVENING. UNSEASONABLE MOISTURE AVAILABILITY INITIALLY FOR THE AREA. ISENTROPIC LIFT MAXED SUNDAY EVENING...BUT CONTINUES THROUGHOUT THE DAY MONDAY. FINALLY...POTENTIAL FOR VERY HIGH WINDS...30 TO 50 MPH... AND NEAR BLIZZARD CONDITIONS. ALL OF THIS HAS TAKEN THE FORECAST TO WINTER STORM WARNING WESTERN AREAS LATER TODAY THROUGH MONDAY. ONE MAIN QUESTION IS HANGING OUT THERE ON THIS FORECAST. FIRST AND FOREMOST IS THE COLD AIR. EVENING UPPER AIR RUNS DON/T HAVE A WHOLE LOT OF COLD. THERE IS MARGINAL COLD AIR AT THE SURFACE UP TO THE CANADIAN BORDER. THERE MAY SOME QUESTION OF MOISTURE. THOUGH SUFFICIENT AMBIENT MOISTURE IS IN PLACE...WEATHER SYSTEM HAS CLEARED THE DEEPER (H85) MOISTURE A BIT FROM THE GULF. UNFAVORABLE FLOW LAST EVENING. WORRY THAT SQUALL LINE LATE SUNDAY EVENING COULD UNDERCUT ADDITIONAL MOISTURE AND LIMIT SNOW AMOUNTS DOWN FROM A VERY HEAVY CATEGORY... ESPECIALLY FROM ABOUT 10Z TO 15Z MONDAY...BEFORE MORE MOISTURE IS ABLE TO WRAP INTO THE AREA...AT THAT TIME ACROSS NORTHERN AREAS. HIGHLY CONDITIONAL FORECAST IS BASED UPON A CHANGE OVER OF SNOW LATE THIS AFTERNOON WESTERN CWFA...AND EXPECTATION OF A HEAVY SNOW BAND 60 TO 80 MILES WIDE CENTERED ALONG HIGHWAY 183. 06Z RUNS CAME IN A BIT FURTHER WEST. SECOND ISSUE IS THE WIND...AND WHILE SNOW AMOUNTS MAY STRUGGLE FOR /HEAVY SNOW CRITERIA/ WINDS OF 30 TO 50 MPH CREATE POTENTIAL FOR BLIZZARD LIKE CONDITIONS. THEREFORE...FELT THE RISK WARRANTED A WARNING FOR WESTERN AREAS AND ADVISORIES FURTHER SOUTH AND EAST. THIS SEEMS TO ALIGN OKAY WITH NEARBY OFFICES...AND DAYSHIFT WILL HAVE TO MONITOR FOR ANY EXPANSION...MOST LIKELY FURTHER SOUTH INTO PHILLIPS AND ROOKS COUNTY KANSAS. THERE IS POTENTIAL FOR SOME THUNDERSTORMS IN THE SOUTHEAST CWFA AS WELL...AND DAYSHIFT WILL ALSO HAVE TO MONITOR THAT. ONLY EDITS TO THE FORECAST WERE WITHIN THE FIRST 48 HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WINTER STORM WARNING LATE THIS AFTERNOON THROUGH MONDAY WEST OF A ST. PAUL TO FRANKLIN LINE. SNOW AND BLOWING SNOW ADVISORY REST OF THE SOUTH CENTRAL NEBRASKA TONIGHT THROUGH MONDAY. KS...SNOW AND BLOWING SNOW ADVISORY LATE SUNDAY AFTERNOON THROUGH MONDAY. && $$ NOAA/NWS/MORITZ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 934 AM EST SUN NOV 27 2005 .SHORT TERM (TODAY)...PRECIP SPREADING INLAND OVER NORTHEAST SOUTH CAROLINA AND EXTREME SOUTHEAST NORTH CAROLINA IN WARM ADVECTION PATTERN. BASED ON RADAR...BULK OF PRECIP WILL REMAIN WEST OF OUR CWA FOR AWHILE...BUT THINK WESTERN CWA WILL HAVE BEST CHC OF SEEING SOME PRECIP THRU THE AFTERNOON HOURS. MADE MINOR CHANGES TO GRIDS AND WILL UPDATE TO REMOVE MORNING WORDING. DESPITE FAIRLY EXTENSIVE CLOUD SHIELD...THE LOW LEVEL WARM ADVECTION SHOULD ALLOW TEMPS TO REACH FCST HIGHS AROUND 60 WEST TO MIDDLE 60S EAST. && .AVIATION...LOWER CLOUDS WILL CONTINUE TO MOVE IN AS THE ATMOSPHERE MOISTENS UP. LIGHT RAIN WILL SPREAD IN THIS AFTERNOON. VISIBILITIES GENERALLY NO LOWER THAN 5 MILES. CEILINGS WILL BE MVFR THROUGH THE PERIOD. SURFACE WINDS WILL BE LIGHT NORTHEAST TODAY THEN VEER TO SOUTHEAST LATE THIS AFTERNOON AND THIS EVENING. && .MARINE...NORTHEAST FLOW ACROSS THE WATERS AT PRESENT. LATEST COASTAL AND OFFSHORE OBS MATCH UP WELL. LATEST RUC40 DELAYS WESTWARD MOVEMENT OF COASTAL TROF UNTIL LATE THIS AFTERNOON INTO THIS EVENING. THE SHIFT TO EAST WINDS WILL OCCUR OVER THE SOUNDS AND NORTH OF CAPE HATTERAS THIS AFTERNOON...AND SHIFT TO SOUTHEAST FOR THE WATERS SOUTH OF CAPE HATTERAS LATE THIS AFTERNOON. THE ZONES WERE WORDED ACCORDINGLY. NO OTHER CHANGES MADE. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FOR AMZ150-152-154-156-158 FROM 7 PM SUNDAY TO 7 PM THURSDAY. && $$ SHORT TERM...COLLINS AVIATION...AUSTIN MARINE...AUSTIN nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 652 AM EST SUN NOV 27 2005 .SHORT TERM (REST OF TODAY)... HAVE JUST SENT A QUICK UPDATE TO GRAPHICAL AND TEXT PRODUCTS TO ACCOUNT FOR A SLIGHTLY QUICKER ENTRANCE OF THE OVERCAST SKIES AND TO BRING IN RAIN CHANCES A FEW HOURS SOONER IN THE SOUTH THIS MORNING. && .PREVIOUS DISCUSSION... (ISSUED 245 AM EST SUN NOV 27 2005) SHORT TERM (TODAY THROUGH TUESDAY NIGHT)... TODAY THROUGH MONDAY: HEALTHY STRIP OF CONVECTION IS PUSHING INTO ALABAMA THIS MORNING WITH IMPRESSIVE GRAVITY WAVES SHOWING UP ON IR SATELLITE IMAGERY. HIGH CLOUDS CONTINUE TO STREAM INTO NC FROM THE SOUTHWEST BUT THE DENSER OVERCAST OF MID AND LOWER LEVEL CLOUDS ARE ON OUR DOORSTEP. SHOWERS GENERATED BY 850 MB MOISTURE FLUX CONVERGENCE ATTENDING THE NORTHEASTWARD MOVING COASTAL FRONT HAVE MOVED ONSHORE OVER COASTAL SC... AND THE RUC/NAM/GFS ALL AGREE ON QUICKLY INCREASING ISENTROPIC UPGLIDE TODAY ON THE 290-295 K SURFACES... WHILE THE APPROACH OF THE UPPER LEVEL TROUGH AND SUBTROPICAL JET FROM THE SOUTHWEST INCREASES UPPER DIVERGENCE AND MOISTURE INFLOW ALOFT WITH MINOR AMOUNTS OF MID LEVEL POSITIVE VORTICITY ADVECTION. HAVE BROUGHT IN CHANCE POPS ACROSS THE SOUTH LATER THIS MORNING THROUGH MIDDAY... THEN WILL HAVE A PERIOD OF LIKELY POPS THIS AFTERNOON AS SKIES GO MOSTLY CLOUDY EVERYWHERE. GFS RAINFALL PATTERN LOOKS A BIT MORE REALISTIC THAN THE NAM WHICH GRABS ONTO SOME 850 MB CONVERGENCE IN EASTERN NC AND FOCUSES AN INORDINATE AMOUNT OF RAIN THERE. DO ANTICIPATE QPF TO BE LESS THAN MODEL PREDICTIONS DUE TO THE GULF COAST CONVECTION WHICH COULD INDUCE WEAK DOWNSTREAM RIDGING OVER NC THIS AFTERNOON. LITTLE CHANGE IS NEEDED TO CURRENT HIGHS WITH NORTHWEST CWA... WHERE THE WEAK SURFACE-BASED STABLE POOL WILL BE THE LAST TO GO... TOPPING OUT AT JUST 50-52 WITH READINGS NEAR 60 IN THE SOUTHWEST CWA. WITH THE EXIT OF THE UPPER JET AND A LOSS OF ANY SUBSTANTIAL FORCING... PLUS WITH CENTRAL NC EXPECTED TO GET MOSTLY INTO THE WARM SECTOR (EXCEPT FOR MAYBE THE TRIAD AREA) WITH BRIEF MID LEVEL SHORTWAVE RIDGING... SHOWERS SHOULD DECREASE TO SCATTERED (WEST) TO ISOLATED (EAST) TONIGHT AND CONTINUE THROUGH MONDAY. DIFFUSE ISENTROPIC UPGLIDE HANGS ON SO CONSIDERABLE CLOUDINESS IS LIKELY BUT UPPER LEVELS SHOULD DRY OUT BETWEEN TROUGHS AS NOTED UPSTREAM ON THE 700 & 500 MB UPPER AIR ANALYSES. EXPECT AREAS OF FOG TO DEVELOP OVERNIGHT WITH LIGHT SOUTHEAST WINDS. CURRENT VERY MILD LOWS IN THE MID 40S TO LOWER 50S LOOK GOOD AND AGREE WITH AVERAGE OF LATEST MOS GUIDANCE. HIGHS 61-72 MONDAY. TUESDAY: THE NEXT ROUND OF SHOWERS AND SCATTERED THUNDERSTORMS APPEARS IMMINENT WITH ALL MODEL PARAMETERS POINTING TO DEEP MOISTURE AND SUFFICIENT FORCING FROM THE RIGHT ENTRANCE REGION OF THE UPPER JET ON THE EAST SIDE OF THE MID LEVEL VORTEX LIFTING ACROSS THE U.P. OF MICHIGAN TOWARD JAMES BAY. WILL HANG ONTO CURRENT CATEGORICAL POPS AS AT LEAST SOME RAINFALL LOOKS INESCAPABLE GIVEN THIS AMOUNT OF LOW LEVEL MOISTURE INFLUX. LOWS 55-60 AND HIGHS 64-72. -GIH LONG TERM (WEDNESDAY THROUGH SATURDAY)... NO SIGNIFICANT CHANGES TO THE CURRENT DRY AND MOSTLY CLEAR TO PARTLY CLOUDY FORECAST WITH PREVAILING BROAD CYCLONIC MID LEVEL FLOW THROUGH THE PERIOD. A DEEP UPPER VORTEX WOBBLES FROM MICHIGAN INTO EASTERN CANADA KEEPING MINOR INEFFECTUAL PERTURBATIONS PASSING THROUGH NC WITH A DRY WESTERLY BOUNDARY LAYER FLOW. LOW LEVEL THICKNESSES OFF THE 00Z/27 GFS DROP TO MORE THAN 50 M BELOW NORMAL FOR FRIDAY/SATURDAY WHICH WOULD TRANSLATE TO HIGHS IN THE 40S TO AROUND 50... NOT FAR OFF CURRENT FORECAST TEMPS. -GIH AVIATION... WEAK ISENTROPIC LIFT WILL ADVECT ATLANTIC MARITIME MOISTURE LATE THIS MORNING AND INTO THE EARLY AFTERNOON. AS A RESULT...CEILINGS WILL LOWER TO MVFR/IFR AND LIGHT RAIN WILL EXPAND FROM SOUTH TO NORTH ACROSS THE FORECAST AREA. LOWER MISS VALLEY S/W TROUGH WILL APPROACH FROM THE SOUTHWEST AFTER 18Z...BRINGING A SECONDARY FLUX OF MOISTURE AND PRECIP FROM 18 TO 00Z. RAIN SHOULD END FROM SOUTH TO NORTH AS S/W TROUGH MOVES NORTH OF THE AREA ~06Z...HOWEVER IFR/LIFR CEILINGS WILL REMAIN IN PLACE AS 1000-850 S/SE FLOW CONTINUES. -BL && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HARTFIELD nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1024 AM EST SUN NOV 27 2005 .SHORT TERM (REST OF TODAY)... WITH THE WEDGE SETTING UP...HAVE LOWERED MAX HIGHS FOR TODAY. PRECIP HAS ASSISTED IN THE SUPPRESSION OF THE TEMPERATURES...ESPECIALLY IN THE EAST. MANY OTHER GRIDS WERE TWEAKED IN ACCORDANCE WITH THE LATEST OBSERVATIONS AND SATELLITE IMAGES. OMEGA SETS UP OVER THE MOUNTAINS ON THE RUC LATE THIS AFTERNOON BUT HAD LITTLE RESPONSE IN THE MODEL FOR PRECIP. OVERALL...I HAVE RAISED POPS EVERYWHERE...MORE SO WHERE RAIN WAS MOVING ACROSS OR TOWARD. THE LAKE WIND ADVISORY FOR THE SOUTHWEST MOUNTAINS IS MARGINAL AT THIS POINT...BUT WITH ALL CONSIDERED...I CANNOT DROP IT FOR THIS AFTERNOON. LIGHT WIND AT THE LOWER ELEVATIONS. THERE IS SOME SOMEWHAT BREEZY CONDITIONS AT THE HIGHER POINTS AND WILL GET BREEZIER AS WE PROGRESS TOWARD THE END OF THE DAY. && .PREVIOUS DISCUSSION... (ISSUED 359 AM EST SUN NOV 27 2005) SHORT TERM (TODAY THROUGH TUESDAY NIGHT)... ATLANTIC MOISTURE ADVECTING INTO THE MIDLANDS AND SOUTHERN UPSTATE PER LATEST REGIONAL COMPOSITE AND FOG PRODUCT. EXPECT EARLY MORNING PRECIPTATION TO BE LIGHT AND MAINLY SCATTERED IN NATURE. ISENTROPIC LIFT INCREASES THIS AFTERNOON ACROSS THE PIEDMONT AND UPSLOPE AREAS SHOULD SEE THE BEST CHANCES OF PRECIP THROUGH THE EVENING HOURS. ISSUED A LAKE WIND ADISORY FOR THE SOUTHERN MOUNTAINS TODAY AS PRESSURE GRADIENT TIGHTEN RAPIDLY WITH DEEPENING WESTERN LOW. A RELATIVE MINIMA IN ACTIVITY IS EXPECTED TONIGHT THROUGH MONDAY MORNING AS RETREATING SFC HIGH REDUCES LOW LEVEL LIFT. DECENT CONVERGENCE ZONE SETS UP ACROSS EASTERN TENNESSEE MONDAY AFTERNOON AND WILL BE SHIFTED EAST AS UPPER TROF SWINGS OUT OF THE CENTRAL PLAINS. WILL CONFINE LIKELY POPS TO THE MOUNTAINS MONDAY AFTERNOON AND SHIFT EAST DURNING THE EVENING. SOME THUNDER IS STILL ANTICIPATED AS H85 JET REACHES 50 KTS AND UPPER DIVERGENCE MAXIMIXES. ALSO...HIGH DEWPOINTS ACROSS THE MOUNTAINS SHOULD MAKE DYNAMIC LIFTING MORE EFFICIENT AS WELL. EXPECT PRE-FRONTAL ACTIVITY TO CROSS THE CWFA THROUGH TUESDAY AND GENERALLY WEAKEN...HOWEVER AREAL COVERAGE SHOULD BE HIGH ENOUGH TO KEEP POPS FAIRLY HIGH. LONG TERM (WEDNESDAY THROUGH SATURDAY)... COOL/DRY HIGH PRESSURE BEHIND FRONT SETTLES OVER AREA WED/THU. ANOTHER FRONT REINFORCES COOL AIR FROM NW THU NIGHT...ACCOMPANIED BY ONLY MEAGER MOISTURE. COOLER/DRIER RIDGE OF A MORE NORTHERLY SOURCE REGION MOVES INTO AREA SAT. AVIATION... LLVL ISENTROPIC LIFT AND MOISTURE WILL CONTINUE TO BUILD NORTH OVER A WEDGED AIR MASS LATE TONIGHT AND TOMORROW. CAD CONDITIONS ARE EXPECTED TO MATURE THROUGH THE TAF PERIOD. CONDITIONS ARE EXPECTED TO GRADUALLY BECOME IFR AFTER 18Z SAT. IN ADDITION...DZ AND -RA SHOULD DEVELOP OVER THE TERMINALS DURING THE LATE MORNING AND LATE AFTERNOON RESPECTIVELY AND REMAIN THROUGH THE REST OF THE TAF PERIOD. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...LAKE WIND ADVISORY FOR NCZ051-052-058-059-062>064 UNTIL 6 PM SUNDAY. SC...NONE. && $$ SHORT TERM...DEO sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 916 AM EST SUN NOV 27 2005 .SHORT TERM /THIS AFTERNOON/...A STRONG WEDGING PATTERN IS IN PLACE THIS MRNG WITH LGT PCPN OVR THE MIDLANDS AND PEE DEE HELPING TO REINFORCE IT. HAVE SERIOUS DOUBTS THAT THE WEDGE WL BREAK DOWN AS QUICKLY AS WHAT THE NAM AND GFS SOLNS SUGGEST ESP GIVEN THAT SFC PRESSURES ARE STILL RISING INLAND. PLAN TO STICK CLOSER TO THE LATEST RUC OUTPUT WHICH KEEPS THE WEDGE FIRMLY IN PLACE THROUGH THE AFTN AND HOLDS THE COASTAL TROF OVR THE COASTAL WTRS. FOR THIS REASON...WE WL LWR TEMPS BY 10-15 DEGS AND INCR CLOUD COVER TO CLOUDY ALL AREAS WITH THE MRNG UPDATE. CONTD WK ISENTROPIC LIFT WL KEEP A CHANCE FOR LGT PCPN GOING THROUGH THE DAY WITH A FAIRLY HIGH POTENTIAL FOR DRIZZLE. THANKS FFC/ILM/CAE FOR THE COORD. && .MARINE...TRICKY FCST THIS MRNG WITH THE COASTAL TROF BASICALLY BISECTING THE NEARSHORE WTRS. WNDS AT 41004 AND THE TYBEE TWRS ARE SELY WHILE THE VARIOUS CARO-COOPS SITES ALONG THE SC COAST ARE SOLIDLY N TO NE. WITH THE COASTAL TROF NOT XPCTD TO MOVE MUCH FARTHER TO THE W TDA...PLAN TO SLIT THE NEARSHORE WTRS WND FCST SHOWING NE WNDS WITHIN 10 NM OF THE COAST AND SE WNDS BEYOND 10 NM. SEAS AT SPAG1 HAVE DROPPED BELOW 5 FT FOR THE FIRST TIME IN SEVERAL HRS AFTER PEAKING AROUND 7 FT AROUND 2 AM. SUSPECT SEAS HAVE DROPPED BELOW 6 FT ACROSS MUCH OF THE GA OFFSHORE WTRS SO WL PUSH BACK THE BEGINNING TIME OF THE SCA INTO TNGT AS IT DOES NOT APPEAR THAT SCA CONDITIONS WL BE MET THIS AFTN INTO THIS EVNG. THANKS OPC FOR THE COORD. && .AVIATION...HAVE RECENTLY UPDATED BOTH TERMINALS FOR MUCH MORE PESSIMISTIC CONDITIONS OVR THE NXT 6-8 HRS. STRONG WEDGE WL KEEP IFR AND LOW END MVFR CIGS GOING FOR MUCH OF THE DAY AS THE MODELS APPEAR TOO QUICK IN BREAKING DOWN THE WEDGE THIS AFTN. WL LIKELY MAKE ADDITIONAL ADJUSTMENTS WITH 18Z TAF CYCLE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS BEGINNING TONIGHT FOR AMZ374. && $$ ST sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 420 AM MST SUN NOV 27 2005 .SYNOPSIS...A COLD...MOIST AND UNSTABLE AIRMASS WILL LINGER OVER THE AREA TODAY. HIGH PRESSURE WILL BRIEFLY RETURN MONDAY...BEFORE ANOTHER PACIFIC SYSTEM SPREADS MOISTURE INTO THE AREA MONDAY NIGHT INTO TUESDAY. && .DISCUSSION...DEEPENING UPPER LOW EVIDENT IN EARLY MORNING WATER VAPOR IMAGERY OVER THE SOUTHERN ROCKIES WITH 160KT 250MB JET EXTENDING ALONG BACK SIDE OF LARGER SCALE CYCLONIC FLOW ACROSS NV INTO SOUTHERN AZ. VERY COLD AIR ALOFT /-32C AT 500MB AND -15C AT 700MB PER RUC/ IN PLACE ACROSS THE FORECAST AREA THIS MORNING. THIS IS RESULTING IN AN UNSTABLE AIRMASS AND ALLOWING FOR DEVELOPMENT OF BANDED PRECIPITATION OVER THE GREAT SALT LAKE. THESE BANDS HAVE BEEN TRACKING SOUTHWARDS INTO EASTERN TOOELE COUNTY AND WESTERN SALT LAKE COUNTY OVER THE PAST FEW HOURS...AND EXPECT THESE TRAJECTORIES TO GENERALLY CONTINUE THROUGH THE MORNING HOURS AS LITTLE CHANGE IN WIND DIRECTION ALOFT IS INDICATED BY MODELS. HAVE CONTINUED HEAVY SNOW WARNING FOR ZONES 3 AND 4...WITH HEAVIEST SNOW EXPECTED ACROSS WESTERN SALT LAKE COUNTY. GIVEN TRAJECTORIES OFF LAKE...HAVE CANCELED HEAVY SNOW WARNING FOR NORTHERN WASATCH FRONT. OTHERWISE GIVEN UNSTABLE AIRMASS AND NORTHWESTERLY FLOW ALOFT EXPECT SNOW TO CONTINUE ACROSS HIGHER TERRAIN OF NORTHERN AND CENTRAL UT...AND HAVE CONTINUED GOING HEAVY SNOW WARNING THERE AS WELL. IN FACT SNOW SHOWERS WILL LIKELY REMAIN ACROSS HIGHER TERRAIN THROUGH MUCH OF THE DAY...AS PROG SOUNDINGS FROM NAM INDICATE WARMING ALOFT DOES NOT COMMENCE UNTIL THIS EVENING ACROSS NORTHERN UT. SURFACE HIGH EXPECTED TO BRIEFLY SETTLE ACROSS THE FORECAST AREA TONIGHT...AND GIVEN RECENT SNOWFALL EXPECT TEMPERATURES TO FALL BELOW GUIDANCE VALUES PARTICULARLY IN SHELTERED AREAS. AFTER TODAY...AN ACTIVE WEEK APPEARS IN STORE FOR THE MOUNTAINS OF NORTHERN AND CENTRAL UTAH. SHORTWAVE RIDGING PROGGED TO BUILD ACROSS THE AREA MONDAY INTO MONDAY NIGHT. AS THIS RIDGE AXIS PASSES EAST OF FORECAST AREA...STRONG WARM ADVECTION WILL LEAD TO ANOTHER ROUND OF SNOWFALL ACROSS NORTHERN AND CENTRAL MOUNTAINS MONDAY NIGHT INTO TUESDAY. THIS IS IN ADVANCE OF A NORTHERN STREAM SHORTWAVE WHICH WILL BRUSH THE AREA TUESDAY NIGHT...AND PUSH A COLD FRONT INTO NORTHERN UTAH WEDNESDAY MORNING. MOIST WEST SOUTHWESTERLY FLOW LOOKS TO REMAIN ACROSS THE AREA THROUGH FRIDAY...BEFORE YET ANOTHER SHORTWAVE TROUGH PROGGED TO IMPACT THE AREA LATE FRIDAY INTO SATURDAY. && .AVIATION...A MOIST NORTHWEST FLOW WILL CONTINUE THROUGH THIS MORNING. COINCIDENTALLY THIS IS THE CLIMATOLOGICAL PEAK OF RECEIVING LAKE-ENHANCED SNOW SHOWERS AT SLC. EVEN SO THE TIMING OF SUCH SNOW SHOWERS OR SQUALLS REMAINS DIFFICULT SO WILL HAVE TO BROAD BRUSH WITH TEMPORARY MVFR CONDITIONS BUT THERE IS POTENTIAL FOR OCCASIONAL IFR AND LIFR...BUT THEIR DURATIONS SHOULD BE LESS THAN 15 MIN. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...HEAVY SNOW WARNING THROUGH NOON ZONES UTZ002>004-006>010-017. SNOW ADVISORY THROUGH NOON ZONES UTZ015-016. WIND ADVISORY UNTIL 8 AM ZONE UTZ005. WY...NONE. && $$ PUBLIC...SEAMAN AVIATION...STRUTHWOLF ut AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 435 PM EST SUN NOV 27 2005 .DISCUSSION... MAIN FCST CONCERNS ARE RAIN/FOG TRENDS TSRA CHANCES FOLLOWED BY SN/LES POTENTIAL MID AND LATE WEEK. WV IMAGERY...12Z RAOBS AND RUC ANALYSIS INDICATED A VIGOROUS MID LEVEL LOW INTO THE SRN PLAINS. ONE SHRTWV WAS LIFTING NE THROUGH SRN WI WHILE ANOTHER WAS ON ITS HEELS OVER NRN MO IN ADVANCE OF 120 KT 300 MB JET. AT THE SFC...A 989 MB TROF EXTENDED FROM CNTRL KS INTO THE TX/OK PANHANDLE. A WARM FRONT WAS DRAPED FROM SRN MN THROUGH SRN WI TO SRN LWR MI WITH DEWPOINTS IN THE UPPER 40S TO LOWER 50S SOUTH OF THE FRONT. THE COMBINATION OF QVECTOR CONV AND 295K-300K ISENTROPIC LIFT AHEAD OF THE WI SHRTWV IN AN UNSEASONABLY MOIST AIRMASS(PWAT NEAR 1.0 INCH) SUPPORTED WIDESPREAD RAIN ACRS NRN WI AND UPR MI. ALTHOUGH WARM/MOIST ADVECTION HAS BROUGHT DEWPOINTS INTO THE MID AND UPPER 30S WITH AREAS OF FOG...THE RAIN HAS HELPED LIMIT DENSE FOG FORMATION SO FAR. TONIGHT...RADAR/SATELLITE TRENDS AND 18Z RUC SUGGEST PERIODS OF RAIN SHOWERS TO CONTINUE THIS EVENING AS WI SHRTWV GIVES WAY TO ADDITIONAL FORCING FROM NEXT UPSTREAM SHRTWV. EXPECT RAIN TO BECOME MORE SCATTERED BY 03Z-06Z AS THE SECOND SHRTWV LIFTS OUT. AS THE PCPN TAPERS OFF EXPECT FOG TO BECOME MORE DENSE AND WIDESPREAD. SO...DENSE FOG ADVY WAS ISSUED. MON...EXPECT DENSE FOG TO LINGER INTO THE MORNING UNTIL RAIN AGAIN BECOMES MORE WIDESPREAD TOWARD AFTERNOON AS QVECTOR CONV AND UPR LVL DIV AS THE UPR LVL JET LIFTS OVER LK MI TOWARD ERN UPR MI. GOING TSRA CHANCES ALSO LOOK ON TRACK GIVEN WITH STRONG FORCING AND LIKELIHOOD OF ELEVATED CAPE VCNTY OF THE APPROACHING JET. ONSET OF RAIN SHOULD HELP IMPROVE VISIBILITIES SOMEWHAT EVEN THOUGH WAA COULD PUSH TEMPS/DEWPOINTS WELL INTO THE MID AND UPPER 40S. MON NIGHT INTO TUE...THE SLOWER NAM/UKMET SUPPORTED BY THE CMC MDLS WITH A TRACK A BIT FARTHER WEST THAN THE GFS WAS PREFERRED GIVEN THE INTENSITY THE LOW. THE DRY SLOT SHOULD EDGE INTO THE AREA WITH MID LVL DRYING PROMOTING MAINLY AREAS OF -DZ/-RA. AGAIN DELAYED CHANGEOVER TO SNOW...PER NAM SNDGS/ FCST FREEZING LVLS. ARRIVAL OF COLDER AIR WITH 850 MB TEMPS DROPPING OFF TO THE -7C TO -10C RANGE IN THE AFTERNOON WHILE DEEP MOISTURE AND CYCLONIC FLOW IS IN PLACE COULD BRING AN INCH OR TWO OF LAKE ENHANCED SNOW TO THE WEST WHILE THE REST OF THE AREA WOULD SEE LESS THAN AN INCH FROM WRAP-AROUND PCPN WITH DELAYED CHANGEOVER TO SNOW. TUE NIGHT INTO WED...ENOUGH COLD AIR POURS INTO THE AREA FOR NW FLOW LES TO BRING A FEW INCHES OF SNOW AS H8 TEMPS FALL TO AROUND -12C/14C...PER UKMET/GFS. LIMITING FACTOR FOR BETTER ACCUMULATIONS WILL BE DEPARTING DEEP MOISTURE AND MODEST INVERSION HGTS...LIKELY IN THE 4K-5K FT RANGE. THU-SUN...FCST LEANED TOWARD THE 00Z/27 ECMWF...PER HPC...WHICH HAS BEEN LEADER IN SUGGESTING A SLOWER MORE BLOCKED PATTERN INTO THE WEEKEND. EARLY IN THE PERIOD...THE GLBL MDLS STILL SUGGEST A WAVE MAY BRUSH THE AREA WITH A SHRTWV AND ASSOCIATED SFC LOW PRODUCING AN AREA OF LIGHT SNOW. A DECENT NW FLOW LES REGIME WILL FOLLOW AND PERSIST INTO THE WEEKEND WITH 850 MB TEMPS FALLING TO THE -16C TO -18C RANGE. UNCERTAINTY IS LARGE BY THIS WEEKEND WITH MDLS/ENSEMBLES DISPLAYING WIDE RANGE OF POSSIBILITIES IN HANDLING FATE OF THE MID LVL LOW OVER SE CANADA. PREFERRED ECMWF SOLUTIONS WOULD SUGGEST THAT MORE N OR NW LES WOULD CONTINUE WHILE GFS WOULD BRING IN RETURN OF WAA AFTER SFC RDG PASSES THROUGH. && .MQT...WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY FROM 10 PM EST /9 PM CST/ THIS EVENING TO 12 PM EST /11 AM CST/ MONDAY FOR MIZ001-MIZ002-MIZ003-MIZ004-MIZ005-MIZ006-MIZ007-MIZ009-MIZ010-MIZ011 -MIZ012-MIZ013-MIZ014-MIZ084-MIZ085. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1204 PM EST SUN NOV 27 2005 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE CHANCE OF RAIN OR FREEZING DRIZZLE TODAY. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A CLOSED LOW OVER NORTHEAST NEW MEXICO AND A RIDGE EXTENDING FROM MID ATLANTIC STATES NORTHWEST THROUGH THE UPPER GREAT LAKES INTO SOUTHERN MANITOBA. WEAK SHORTWAVE ARE BEING EJECTED OUT AHEAD OF THE NEW MEXICO LOW AND SAILING THROUGH THE UPPER GREAT LAKES. SURFACE ANALYSIS DEPICT A HIGH OVER MAINE AND A DEEP LOW OVER SOUTH CENTRAL KANSAS. A WARM FRONT STRETCHES EAST FROM THIS LOW THROUGH SOUTHERN WISCONSIN AND LOWER MICHIGAN. MOISTURE OVERRUNNING AND ISENTROPIC ASCENT NORTH OF THIS FRONT IS GENERATE SCATTERED RAIN SHOWERS ACROSS THE WEST HALF OF THE U.P. A WEAK SHORTWAVE EJECTED OUT AHEAD OF THE LOW OVER SOUTH CENTRAL CONUS WILL SWEEP INTO WISCONSIN AND LOWER MICHIGAN THIS AFTERNOON. THE ACCOMPANYING WARM FRONT WILL MAKE ITS WAY INTO UPPER MICHIGAN THIS AFTERNOON. MORNING RAOBS AND FORECAST SOUNDINGS SHOW NEARLY SATURATED CONDITONS FROM SURFACE TO 500MB ALONG AND AHEAD OF THE FRONT. THE SHORTWAVE ENERGY AND THE FRONT WILL CONTINUE TO GENERATE SHOWERS OVER THE FORECAST AREA THIS AFTERNOON. WARM AIR ADVECTION WILL CHANGE ALL THIS OVER TO RAIN. 850MB TEMPERATURE IS AT 4C AND WILL INCREASE TO 7C BY LATE AFTERNOON CREATING A STRONG SURFACE BASE INVERSION. FOG WILL ALSO FORM WITH THE RAIN AND WARM AIR ADVECTION...SO WILL LEAVE THESE IN THE FORECAST. ALL SURFACE REPORTING STATION INDICATE THAT THE TEMPERATURE IS AT OR ABOVE FREEZING...SO WILL NOT EXTEND THE FREEZING RAIN ADVISORY. TEMPERATURES ARE WELL ON THEIR WAY TO AROUND 40F FOR A HIGH THIS AFTERNOON. THE WARMEST TEMPERATURES SHOULD BE ALONG LAKE MICHIGAN SHORE WHERE THE LAKE TEMPERATURE IS AROUND 40 AT THIS TIME AND THE WINDS ARE ONSHORE. THE SHORTWAVE OVER WISCONSIN AND LOWER MICHIGAN WILL SLIDE ACROSS THE FORECAST AREA TONIGHT AS THE WARM FRONT MOVES INTO LAKE SUPERIOR. LOW LEVEL MOISTURE SHOULD PREVAIL THROUGH THE NIGHT. A SURFACE BASE INVERSION WILL CONTINUE AS WELL. THIS WILL KEEP RAIN AND FOG IN PLACE THROUGH THE NIGHT. DO NOT PLAN TO MAKE ANY CHANGES TO THE NIGHTTIME FORECAST AT THIS TIME. WILL UPDATE TO THE ZFP FOR WORDING AND TO REMOVE THE ADVISORY INFO. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1100 AM CST SUN NOV 27 2005 .UPDATE... EXTENDED AND MODIFIED THE FREEZING RAIN ADVISORY FOR MOX TO LXL AREA. FREEZING DRIZZLE CONTINUING LATE THIS MORNING AND DENSE FOG HAS SHOWN UP AS WELL. THEREFORE HAVE SWITCHED IT OVER TO A WINTER WX ADVY THROUGH 4 PM. THX FGF FOR COORD. THIS AREA IS SOME DISTANCE NORTH OF FRONT. LATEST RUC SUGGESTS FOG WILL NOT ABATE FOR AWHILE. RUC AND SFC ANALYSIS SUGGEST LO LVL TEMPS WILL LIKELY REMAIN AOB 32 INTO MID AFTERNOON...ESPECIALLY FROM AXN TO LXL. TEMPS SHOULD FINALLY RISE ABOVE FREEZING LATE THIS AFTERNOON AS SYSTEM WINDS UP. AS FOR WINTER STORM WATCH...12Z NAM INDICATES LO LVL TEMPS WILL REMAIN TOO WARM FOR SNOW THROUGH MIDDAY MONDAY...EVEN IN OUR FAR WESTERN COUNTIES. GFS BRINGS IN THE COOLER TEMPS AFTER 12Z MONDAY. MIGHT DECIDE TO PUSH WATCH BACK IN TIME BUT THAT WILL BE DECIDED OVER THE NEXT FEW HOURS. && .PREV DISCUSSION... /ISSUED 435 AM CST SUN NOV 27 2005/ DISCUSSION... RUNNING A BIT BEHIND WITH FREEZING RAIN SITUATION AND HEADLINES. IMPETUS FOR FRZG RAIN ADVY WAS CONVECTION BREAKING OUT IN CENTRAL MN AROUND 0200. QUITE A CHANGE IN PWATS AND MID LEVEL INSTABILITY LAST FEW HOURS AS STRONG SOUTHERLY FLOW ALLOWED FOR RAPID MOISTURE IMPORT. THESE SHOWERS WERE DEVELOPING AND MOVING RAPIDLY NORTHEAST INTO AREA WHERE SURFACE TEMPS WERE ONLY IN LOWER AND MID 20S. AREAS FARTHER SOUTH WHERE MORE WIDESPREAD PRECIP WAS DEVELOPING WERE WARMING FAST ENOUGH TO PREVENT FREEZING. WOULD NOT BE SURPRISED IF MOST OF THE THUNDERSTORMS WERE CONFINED TO THE MORNING HOURS WHEN ATMOSPHERE WAS UNDERGOING ITS MOST RAPID CHANCE. DID NOT MAKE CHANGES TO WATCH HEADLINES OR FORECAST SNOW AMOUNTS IN GRIDS. STILL LOOKS VERY GOOD FOR HEAVY SNOW WESTERN CWA LATE TONIGHT INTO MONDAY EVENING. HUGE NET VERTICAL DISPLACEMENT OF 120 MB ENDING 12Z MONDAY WITH CONTINED VERTICAL MOTION THRU THE DAY. STRONG 200 MB WAA IS ALSO VERY PERSISTENT. 300K ISENTROPIC CHART ALSO SHOWING PROLONGED PERIOD OF LIFT WITH LARGE AMOUNT OF MOISTURE AVAILABLE. WITH MID LEVELS REMAINING QUITE UNSTABLE COULD EVEN SEE SOME THUNDERSNOW IN W CWA. DIFFICULTY REMAINS THE VERY WARM AIRMASS AND TIMING WHEN SUFFICIENT COOLING WILL OCCUR TO CHANGE TO SNOW. THINK THAT BY 12Z MONDAY THE FAR W WILL SEE ACCUMULATING SNOW WITH HEAVY SNOW CONTINUING MONDAY AS LOW LEVELS COOL RAPIDLY AS SURFACE LOW LIFTS NE. ADDED PROBLEM WILL BE STRONG WINDS DEVELOPING AS DEEP LOW LIFTS NE. RAIN SHUD CHANGE TO MAINLY SNOW LATE MONDAY AFTN AND EARLY EVE E MN...BUT WITH WITH A FEW INCHES POSSIBLE. LONGER TERM...WEDNESDAY THROUGH SUNDAY MOST SIGNIFICANT CHANGES WE MADE OCCURRED ON WEDNESDAY THROUGH THURSDAY WHERE SNOW PROBABILITIES WERE MOVED UP TO LIKELY IN RESPONSE TO STRONG WAVE BROUGHT INTO OUR CWA BY THE LATEST GFS. WHILE THE GFS HAS BEEN ERRATIC AT TIMES...THE FACT THAT THE ECMWF MAINTAINS AND STRENGTHENS THIS SAME PIECE OF ENERGY MOVING IN FROM THE PACIFIC NORTHWEST ADDS A GREAT DEAL TO OUR CONFIDENCE FOR AN EXPECTED SNOWY OUTCOME ON WEDNESDAY AND THURSDAY. THE ECMWF HAS AN EXPANSIVE AREA OF NEGATIVE STANDARD DEVIATIONS FOR 850 MB TEMPERATURES (I.E. 1.5 UNITS) OVER THE UPPER MIDWEST ON DECEMBER 1ST SO WE WOULD EXPECT THIS DAY WILL BE THE COLDEST ONE OF THE UPCOMING FIVE DAY PERIOD. THE UKMET APPEARS TO EVOLVE THIS SAME PIECE OF ENERGY INTO THE EASTERN HALF OF AN OMEGA BLOCK BY DECEMBER 1ST WITH THE MPX CWA ON THE WEST END OF THE EASTERNMOST CLOSED LOW OF THE BLOCK. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY EVENING FOR CHIPPEWA-DOUGLAS-LAC QUI PARLE-POPE-STEVENS-SWIFT-TODD- YELLOW MEDICINE. WINTER STORM WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR BENTON-BROWN-KANDIYOHI-MEEKER-MORRISON-REDWOOD-RENVILLE- STEARNS. WINTER WEATHER ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR DOUGLAS-MORRISON-POPE-STEVENS-TODD. WI...NONE. && $$ TDK mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 400 PM CST SUN NOV 27 2005 .DISCUSSION...PRIME TIME FOR SEVERE TSRA APPEARS TO BE 05Z-20Z... SHORT TERM...TONIGHT AND MONDAY...DEEPENING SURFACE LOW IN KS NOW DOWN TO 983MB AND HEADING SLOWLY NE AS UPPER JET CORE ROUNDING THE BASE OF CENTRAL CONUS TROUGH AXIS THROUGH TX. AIR MASS BEGINNING TO RECOVER OVER THE LOWER MS VALLEY WITH 62-64F DEWPOINTS NOSING UP THE RIVER. WHILE DAYTIME STRATUS DECK HAS SPOILED SOME HEATING AT PLACES IN OUR CWFA...75-80F TEMPS HAVE MADE IT INTO NERN LA AND SERN MS. FIRST SQUALL LINE DEVELOPING OVER NE TX/WRN AR COVERED BY TOR WW 876 WHICH GOES UNTIL 04Z. EXPECT THIS WW TO SHIFT EWD TO NEAR MS RIVER LATER THIS EVENING AS MODELS NOW APPEAR TO BE BACKING OFF A BIT ON EXTREME LOW LEVEL SHEAR VALUES WHILE KEEPING MARGINAL SBCAPES/MLCAPES. BEST ESTIMATE IS THE SEVERE PARAMETERS YIELD THE FOLLOWING NUMBERS ALONG THE MS RIVER BY 06Z: SBCAPES/MLCAPES IN THE RANGE OF 600-800J/KG... 0-1KM AND 0-3KM HELICITIES OF 500-600M*M/S*S...SIGNIFICANT SVR PARAMETER 25-30K...AND STG TOR PARAMETER 2.5-3.0M/S*S. 18Z RUC SHOWED 6 HOUR PRES FALLS OF 4MB+ BY 06Z...SFC DEWPOINTS 65-67F AND 700-500MB LAPSE RATES 5.5-6C. MODELS HAVE UNDERESTIMATED 500MB SPEED MAX IN W NOSING INTO THE ARKLATEX AT 110KTS. THESE WINDS RACE THROUGH THE NW HALF OF AR TOWARD MO BOOTHEEL OVERNIGHT SETTING UP A VERY FAVORABLE RIGHT ENTRANCE REGION FOR OUR FA AS S-N LOW LEVEL JET AXIS OF 60KTS AT 850MB MOVES EWD. PRIME DIVERGENCE COUPLET FROM 850-200MB MOVES ALONG A LINE FROM KPBF TO KMEM TO KMKL AND THIS SHOULD EASILY SUPPORT ONGOING SQUALL LINE HEADING OUR DIRECTION. PRE-SQUALL TSRA SEEMS TO BE MINIMAL HOWEVER A MAJOR PROBLEM WILL BE HOW IN TACT THE SRN END OF THE LINE REMAINS WITH DIMINISHING CAPE ON THE E SIDE OF THE MS RIVER FROM 06-13Z. AT THIS TIME...WE BELIEVE A BROKEN LINE OF SUPERCELLS COULD EMERGE S OF HIGHWAY 82 CORRIDOR WHICH WOULD ACTUALLY ENHANCE THE RISK FOR STRONG/VIOLENT TORNADOES...ALBEIT FEWER CASES OF SUCH MOVING INTO THE I-55 CORRIDOR BY SUNRISE(A LITTLE TOO SIMILIAR TO 11/24/2001). THEN EXPECT A REDEVELOPING TSRA LINE ROUGHLY ALONG THE NATCHEZ TRACE PARKWAY DURING THE MORNING HOURS WITH INCREASING INSTABILITY BECOMING AVAILABLE FOR E CENTRAL MS BY MIDDAY. THE SEVERE RISK COULD REACH A SECONDARY PEAK FOR THE KCBM-KMEI AREAS 15-20Z AS ENOUGH FACTORS REMAIN TOGETHER FOR ADDITIONAL SUPERCELL INITIATION. THE BACK OF THE LINE OF STORMS SHOULD START ACCELERATING EWD BY MID AFTERNOON MONDAY LEAVING THE START OF A DRYING AND GRADUALLY COOLING TREND IN ITS PLACE./40/ LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. COLD FRONT SHOULD BE EXITING EASTERN MISSISSIPPI BY LATE AFTERNOON PER OP GFS MODEL. HOWEVER...I HELD SOME LOW POPS OVER INTO THE EVENING...MAINLY UP AGAINST THE STATE LINE...TO HEDGE AGAINST THE SLOWER NAM SOLUTION COMING TO PASS. IF ANY PRECIP DOES LINGER PAST 00Z TUESDAY IN MY EAST CWA THEN ANTICIPATE ONLY BENIGN REMNANTS OF DEPARTING CONVECTION...AND NOTHING SEVERE. SKIES SHOULD CLEAR BEHIND THE FRONT TEMPORARILY TUESDAY NIGHT...BUT STRATOCUMULUS WILL LIKELY COME BACK TO COVER AT LEAST THE NORTH HALF OF THE REGION BY 12Z AS COLD TEMPS ALOFT UNDERNEATH THE UPPER LOW COME SWINGING IN. WENT NEAR MAV TEMPS FOR LOWS AS MINIMUMS MAINLY FROM 40 TO 45 DEGREES SEEM A GOOD COMPROMISE BETWEEN MODERATE COLD AIR ADVECTION AND THE LACK OF GOOD RADIATIONAL COOLING CONDITIONS. COLD AIR CONTINUING TO BUILD IN BEHIND THE COLD FRONT WILL ENSURE A RATHER CHILLY TUESDAY AND TUESDAY NIGHT WITH TEMPERATURES BELOW NORMAL. OCCASIONALLY BREEZY WEST TO NORTHWEST WINDS OVER THIS PERIOD WILL PROVIDE A BIT OF A WIND CHILL WHILE DAYTIME CLOUDS AT LEAST NORTH OF THE INTERSTATE TWENTY CORRIDOR LIMIT WARMING SUNSHINE. WENT CLOSE TO MAV HIGHS (MAINLY 50S) BUT CUT LOWS FOR WEDNESDAY MORNING 2 TO 3 DEGREES AS GOOD RADIATIONAL COOLING CONDITIONS SHOULD PREVAIL AND THE MAV STATS HAVE SHOWS A STRONG WARM BIAS FOR US IN THESE SITUATIONS LATELY. EXPECT MINIMUMS GENERALLY IN THE 30S. UNCERTAINTY INCREASES GREATLY FOR THE REST OF THE LONG TERM PERIOD. THE UPPER PATTERN SEEMS TO TRANSITION INTO A SORT OF QUASI-ZONAL FLOW BY LATE IN THE WORK WEEK OVER MOST OF THE CONUS WITH WAVES OF JET STREAM ENERGY TRACKING QUICKLY WEST TO EAST ACROSS THE NATION. THIS LOOKS TO BE A RELATIVELY ACTIVE PATTERN FOR THE LOWER MISSISSIPPI VALLEY WITH SEVERAL SHOTS OF PRECIP COMING THROUGH THE NEXT 7 TO 10 DAYS. ALSO...MODELS INDICATE COLD AIR PERCHED ALONG THE US/CANADIAN BORDER WILL MAKE A FEW INTRUSIONS AND WILL BE A SOURCE OF BAROCLINICITY TO AMPLIFY A DEVELOPING STORM SYSTEM OR TWO DURING THIS TIME. ALL THAT SAID...THE MODELS ARE HAVING A VERY DIFFICULT TIME WITH THE DETAILS RIGHT NOW...AND THEIR LACK OF RUN-TO-RUN CONSISTENCY DOES NOT INSPIRE MUCH CONFIDENCE IN FINE OUTPUTS (LIKE THE MEX). THUS...I AM INCLUDING 20 POPS PAST FRIDAY WITH HOPEFULLY 10 POPS COVERING THE VERY MEAGER CHANCES FOR SHOWERS THURSDAY. TEMPS WILL BE GENERALLY A LITTLE BELOW AVERAGE AND I WENT CLOSER TO THE MORE CONSERVATIVE ENSEMBLE GUIDANCE GIVEN THE STATED ISSUES WITH THE MEX STATS. /BB/ && .AVIATION... MVFR DECK OF STRATUS OVER THE AREA FINALLY BREAKING UP FOR THE MOST PART WITH A FEW SMALL -SHRA AT 3-5K FT. WINDS ALSO RESPONDING TO DEEP SURFACE LOW AS SOUTHERLY WINDS INCREASING ALONG MS RIVER TO 20-25KTS IN GUSTS. EXPECT FURTHER INTENSIFICATION...FOR GLH...GWO AND JAN AS SUSTAINED WINDS NEAR 18KTS AND GUSTS TO 30KTS WILL DEVELOP OVERNIGHT. LINE OF THUNDERSTORMS(A FEW SVR) WILL APPROACH GLH/GWO/TVR 07-10Z TONIGHT REACHING JAN TOWARD 11-14Z AND LOCAL FLYING CONDITIONS WILL DETERIORATE RAPIDLY. THE LINE PROGRESSES TO NEAR CBM-MCB LINE BY 16Z AND MEI AREA SHORTLY THEREAFTER./40/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 63 68 42 57 / 54 81 11 10 MERIDIAN 65 74 44 58 / 31 90 28 13 VICKSBURG 59 66 39 56 / 70 53 9 6 HATTIESBURG 65 76 45 61 / 20 71 24 9 NATCHEZ 61 66 41 58 / 60 49 7 5 GREENVILLE 57 65 39 54 / 92 36 10 7 GREENWOOD 59 65 40 53 / 70 74 10 10 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...LAKE WIND ADVISORY FROM 9 PM THIS EVENING TO 3 PM CST MONDAY FOR MSZ029-MSZ030-MSZ031-MSZ032-MSZ033-MSZ038-MSZ039-MSZ044- MSZ045-MSZ046-MSZ050-MSZ051-MSZ052-MSZ055-MSZ056-MSZ057- MSZ058-MSZ062-MSZ063-MSZ064-MSZ065-MSZ066-MSZ072-MSZ073- MSZ074. WIND ADVISORY UNTIL 6 AM CST MONDAY FOR MSZ018-MSZ019-MSZ025- MSZ034-MSZ035-MSZ040-MSZ041. LAKE WIND ADVISORY UNTIL 6 AM CST MONDAY FOR MSZ026-MSZ027- MSZ028-MSZ036-MSZ037-MSZ042-MSZ043-MSZ047-MSZ048-MSZ049- MSZ053-MSZ054-MSZ059-MSZ060-MSZ061. LA...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ007-LAZ008-LAZ009- LAZ015. LAKE WIND ADVISORY UNTIL 6 AM CST MONDAY FOR LAZ016-LAZ023- LAZ024-LAZ025-LAZ026. AR...WIND ADVISORY UNTIL 6 AM CST MONDAY FOR ARZ074-ARZ075. && $$ ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 933 AM MST SUN NOV 27 2005 .UPDATE...SATELLITE WATER VAPOR LOOP PLACES THE UPPER LEVEL LOW CURRENTLY OVER SOUTHEAST CORNER OF MONTANA. WRAP AROUND MOISTURE FROM THIS SYSTEM IS PRODUCING WIDESPREAD SNOW SHOWERS...MAINLY EAST OF THE CONTINENTAL DIVIDE. HOWEVER...THESE SHOWERS CONTINUE TO EXTEND INTO THE BLACKFOOT...SEELEY-SWAN AND GLACIER PARK REGION. MOST RELIABLE MODEL TODAY APPEARS TO BE THE RUC...WHICH PREDICTS ONLY SLOWLY IMPROVING CONDITIONS BY LATE AFTERNOON AND THEN RAPIDLY IMPROVING CONDITIONS THIS EVENING. HAVE CONTINUED WITH SNOW AND BLOWING SNOW ADVISORY FOR AREA DISCUSSED ABOVE...MAY END UP EXTENDING THIS ADVISORY THROUGH THE AFTERNOON. THOUGH AT THIS TIME...TIMING LOOKS REASONABLE. && .PREV DISCUSSION... (ISSUED 136 AM MST SUN NOV 27 2005) SHORT TERM...THE STRONG...EASTERLY MIDDLE AND UPPER LEVEL FLOW ALOFT (ON THE NORTHERN EDGE OF A DEPARTING UPPER LOW TO THE SOUTHEAST) HAS ALLOWED FOR THE CLOUD COVER TO EXTEND AS FAR WEST AS EASTERN WASHINGTON WITH SNOW SHOWER ACTIVITY BEING REPORTED AS FAR WEST AS MULLAN PASS AND LEWISTON...IDAHO. EXPECTING FOR THE PRECIP TO BEGIN TO SHUT OFF FROM WEST TO EAST THIS AFTERNOON AS THE UPPER LOW MOVES OVER COLORADO. BEHIND THIS SYSTEM...A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT AND ON MONDAY. HAVE LEFT IN A CHANCE FOR LIGHT SNOW IN THE CLEARWATERS FOR TONIGHT...IN SPITE OF THE RIDGE. THIS IS DUE TO THE PRESENCE OF A RATHER STOUT UPPER JET AND ENERGETIC MID LEVEL NORTHERLY FLOW OVER THE AREA...ABOVE THE RIDGE. OVERNIGHT LOW TEMPS WILL BE COLD IN THE VALLEYS UNDERNEATH THE SURFACE RIDGE AND UNDER LIGHT WINDS WHICH SHOULD HELP STRENGTHEN VALLEY SURFACE INVERSIONS. HOWEVER...THINKING THAT THE PRESENCE OF A MID LEVEL CLOUD DECK SHOULD HELP BUFFER THE OVERNIGHT DROPOFF IN TEMPS. THE NEXT CHANCE FOR PRECIP ARRIVE MONDAY NIGHT AS THE RIDGE BEGINS TO MOVE EAST AND AS A SYSTEM BEGINS TO APPROACH. APPEARS THAT THE GFS IS HAVING A BIT OF DIFFICULTY WITH THE EVOLUTION AND TRACK OF THE LOWER AND MIDDLE LEVEL PORTION OF THIS SYSTEM. LATEST MODEL RUNS HAVE SLOWED DOWN THE ITS APPROACH AND HAVE MADE IT MORE OF A TUESDAY EVENT INSTEAD OF A MONDAY NIGHT EVENT. REGARDLESS OF THE TIMING...SNOW ADVISORIES MAY BE NEEDED AGAIN FOR THE MOUNTAIN LOCATIONS ACROSS CENTRAL IDAHO AND WESTERN MONTANA. GIVEN THE UNCERTAINTY IN TIMING...WILL HANDLE THIS IN THE HWO FOR NOW. LONG TERM...TUESDAY THROUGH SATURDAY...MODELS HAVE BEEN PRETTY CONSISTENT WITH KEEPING A PROGRESSIVE WET PATTERN OVER THE AREA THROUGH THE EXTENDED PERIOD...WITH TEMPERATURES NEAR NORMAL. THE SYSTEM ON TUESDAY IS STILL LOOKING TO BE A GOOD SNOW PRODUCER IN THE MOUNTAINS...AND COULD WARRANT HIGHLIGHTS IN THE NEAR FUTURE. && AVIATION...SNOW SHOWER ACTIVITY ALONG THE CONTINENTAL DIVIDE AND IN THE NORTHERN PORTION OF THE FLATHEAD VALLEY WILL CONTINUE UNTIL AT LEAST EARLY AFTERNOON. OTHERWISE SCATTERED SNOW SHOWERS WILL DECREASE FROM WEST-TO-EAST DURING THE DAY TODAY. PLEASE CONTINUE TO MONITOR THE TWEBS AND TAFS FOR UPDATES. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...SNOW AND BLOWING SNOW ADVISORY UNTIL 2 PM SUNDAY FOR WEST GLACIER REGION...POTOMAC/SEELEY LAKE REGION. ID...NONE. && $$ UPDATE...MWJ PREV DISCUSSION...HENRY/KOLATA AVIATION...MWJ mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 303 PM CST SUN NOV 27 2005 .SHORT TERM... SHORT TERM MODELS STILL IN DECENT CONTINUITY FROM RUN TO RUN IN THE OVERALL PICTURE. NAM HAS BEEN THE WORST RUN TO RUN...WITH GFS BETTER AND MORE CONSISTENT. HOWEVER DO PREFER MORE OF A BLEND OF THE TWO AS GFS MIGHT BE A TAD TOO FAST IN BRINGING IN 850 MB COOLING EASTWARD WHILE NAM MIGHT BE TOO SLOW. SYSTEM IS GETTING GOING NOW OVER NCNTRL KS WITH SFC LOW A BIT FARTHER WEST THAN PROGGED...TO THE WEST OF CONCORDIA. PER SWOMCD AND RADARS LARGE AREA OF PCPN HAS BEEN ADVECTING NORTHWARD TODAY AND THEN WRAPPING WESTWARD WITH MOST OF IT FALLING ALONG AND WEST OF INVERTED TROUGH WHICH HAS BEEN LOCATED NR A DTL-FFM-ETH LINE. EXPECT LITTLE MOVEMENT OF THIS TROUGH AND PCPN FIELD WITH HEAVIEST FREEZING RAIN WEST OF THIS TROUGH TONIGHT OVER SE ND...WITH TEMPS AROUND 32F OR JUST A BIT ABOVE EAST OF THIS TROUGH OVER WCNTRL MN. FOR SOUTHEAST ND/WCNTRL MN... NAM AND RUC 850 MB TEMPS ARE WARMEST INDICATING ZERO AND ABOVE 850 MB TEMPS HOLDING NR A FSE-FAR LINE TIL NR 18Z MON...WHILE GFS IS A BIT FASTER MOVING IT EAST. USED COMPROMISE WHICH WOULD KEEP FREEZING RAIN PROFILE GOING ALL NIGHT OVER SE ND INTO WCNTRL MN...CHANGING TO SNOW MONDAY MORNING IN SE ND AND AFTER 18Z OVER WCNTRL MN. LOTS OF QUESTIONS ON HOW MAIN SNOW BAND WILL SET UP NORTHWEST OF 500 MB/SFC LOW AS IT DOES FINALLY MOVE NORTHEAST TOWARD MINNEAPOLIS MONDAY AFTN. CONSENSUS IS FOR MAIN BAND FROM FAR NE SD/FAR SE ND INTO NCNTRL MN WITH TOTALS 4-6 WITH ISOLATED HIGHER AMTS. MAIN BACKEDGE OF THIS SNOW BAND LOOKS LIKE IT SHOULD BE NR A LISBON TO JUST WEST OF FARGO TO FOSSTON TO BAUDETTE LINE WITH SHARPLY LOWER AMTS WEST OF THIS LINE. THUS WARNING FOR SE ND INTO WCNTRL MN LOOKING GOOD WITH LIKELY 0.25 OR MORE ICE TONIGHT (ALL AREAS EAST AND SOUTH OF FFM) AND THEN SNOW MON AFTN/EVE. FOR EAST CENTRAL ND INTO NW CORNER OF MN... MUCH MORE IFFY FCST FOR AREAS FROM FINLEY AND MAYVILLE TO GRAND FORKS...THIEF RIVER FALLS AND ROSEAU. PCPN CONTINUES TO TRY TO ADVECT NORTH AND WEST BUT LOW LEVELS A BIT DRIER IN THIS AREA THAN FARTHER SOUTH. BUT MOISTENING WILL OCCUR THIS EVENING AND DO EXPECT A PERIOD OF FREEZING RAIN...THOUGH MUCH LIGHTER THAN SOUTHERN AREAS. THEN 850 MB TEMPS COOL ENOUGH FOR SOME -SN AFTER MIDNIGHT INTO MONDAY MORNING...BUT LOOKS LIKE MAIN SNOW BAND EAST OF GFK-ROX LINE SO NOT REALLY EXPECTED TOO MUCH HVY ACCUM. FELT WARNING STILL JUSTIFIED HERE INSTEAD OF ADVISORY DUE TO FREEZING RAIN FOLLOWED BY SOME LIGHT SNOW AND WIND WITH THIS SYSTEM...DESPITE EACH ELEMENT NOT LIKELY TO REACH WARNING CRITERIA. LOTS OF PEOPLE ON ROADS AS WELL TONIGHT. FOR DVL BASIN... KEPT LOW POP GOING (20 PCT) BUT EXPECT LITTLE MEASURABLE PCPN FROM THSI SYSTEM AS DRIER AIR WINS OUT FROM THE NORTH. AS FOR WINDS...NORTH WINDS OF 25 TO 40 MPH WILL BLOW MONDAY INTO MONDAY NIGHT. SO WHOMEVER GETS SNOW FROM THIS WILL SEE REDUCED VSBY IN BLOWING SNOW AND QUITE POSSIBLY BLIZZARD CONDITIONS DEPENDING ON DEPTH OF NEW SNOWFALL. BEST WIND PERIOD MON 18Z TIL 06Z TUE. LITTLE TIME FOR TUES-WED WEATHER BUT DOES LOOK QUIET ON TUESDAY THEN A WEAK 500 MB SYSTEM TO CROSS AREA ON WEDNESDAY WITH LOW THREAT FOR -SN. STRONGER SFC LOW WILL GO TO OUR SOUTH OVER SRN SD/NRN NE WITH A BIGGER THREAT FOR SNOW DOWN THERE. TEMPS TO BE A BIT BLO NORMAL. .LONG TERM... ONG TERM (THU-SUN)...MOST OF EXTENDED REMAINS THE SAME EXCEPT FOR LOWERING TEMPS A FEW DEGREES FRI MORN AS MOST OF REGION WILL BE SITTING UNDER HIGH WITH THICKNESS VALUES PLUNGING TOWARD 500 DECAMETERS. GUIDANCE IN GENERAL AGREEMENT WITH PROGRESSIVE SHORT WAVE LATE WED INTO EARLY THURS SLIDING SURFACE LOW WELL SOUTH. KEPT LOW POPS ENTIRE CWA ALTHOUGH ANY PCPN MAY VERY WELL BE ACROSS SOUTHERN SECTIONS. KEPT SAT DRY ATTM...WITH THE NEXT SYSTEM PROBABLY TAKING SIMILAR TRACK. && .AVIATION...CIGS/VSBY FADING RAPIDLY TO IFR WITH SMORGASBORD OF ICE...PELLETS AND EVENTUALLY...SNOW THIS EVE THROUGH MON MORNING. WIND BECOMES AN ISSUE OVERNIGHT...WITH GUSTS TO OVER 30 KTS GFK/FAR. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER STORM WARNING UNTIL MIDNIGHT CST MONDAY NIGHT FOR NDZ038- NDZ039-NDZ049-NDZ052-NDZ053. WINTER STORM WARNING UNTIL MIDNIGHT CST MONDAY NIGHT FOR NDZ027- NDZ029-NDZ030. MN...WINTER STORM WARNING UNTIL MIDNIGHT CST MONDAY NIGHT FOR MNZ002- MNZ003-MNZ015-MNZ016-MNZ022-MNZ023-MNZ027-MNZ028-MNZ029- MNZ030-MNZ031-MNZ040. WINTER STORM WARNING UNTIL MIDNIGHT CST MONDAY NIGHT FOR MNZ006- MNZ009-MNZ017-MNZ024-MNZ032. WINTER STORM WARNING UNTIL MIDNIGHT CST MONDAY NIGHT FOR MNZ001- MNZ005-MNZ007-MNZ008-MNZ013-MNZ014. && $$ RIDDLE/WJB nd