AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1000 PM EST MON JAN 16 2006 .UPDATE... THE GENERAL TREND OF COMPUTER GUIDANCE SUPPORTED BY REGIONAL RADAR TRENDS SUGGESTS A CONTINUED DELAY OF PCPN INTO OUR AREA UNTIL AROUND DAYBREAK TUESDAY. WE WILL ISSUE A QUICK ZONE UPDATE TO REFLECT THIS. THE VAST MAJORITY OF THE NIGHT WILL IN FACT BE DRY. ON TUESDAY IT APPEARS THE MAJORITY OF OUR CWA WILL HAVE MAX TEMPS ABOVE FREEZING WITH PCPN TRANSITIONING TO ALL LIQUID. HOWEVER BASED ON 00Z NAM GUIDANCE JUST ROLLING IN AND ALSO THE RUC P-TYPE PROG... I AM CONCERNED THAT OUR FAR NORTH/NE CWA MAY BE STUCK AROUND FREEZING WITH (POTENTIAL) FOR A PROLONGED LIGHT FREEZING RAIN EVENT FROM DAYBREAK TUESDAY THROUGH MUCH OF THE DAY. WE WILL REEVALUATE THIS OVERNIGHT AFTER ALL 00Z GUIDANCE IS IN. FURTHERMORE... RAPID CYCLOGENESIS WILL OCCUR AND I SUSPECT MOST OF OUR AREA COULD BE IN FOR A DECENT LITTLE SNOW EVENT TUESDAY NIGHT (EASY 2 TO 4 INCHES FOR MUCH OF OUR AREA... PERHAPS A LITTLE MORE). AGREE WITH DTX/APX THAT NO HEADLINES ARE NECESSARY AT THE MOMENT. HOWEVER WE WILL HAVE TO MAKE SOME TOUGH HEADLINE AND FORECAST DECISIONS OVERNIGHT FOR TUESDAY AND TUESDAY NIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. && $$ LAURENS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 944 PM EST MON JAN 16 2006 .UPDATE... FORECASTS UPDATED TO SLOW DOWN ARRIVAL OF PRECIPITATION TO TOWARD DAYBREAK. 18Z NAM AND ALSO RUC SEEMED TO BE HANDLING QPF EXTENT SOUTHWEST OF AREA BEST THIS EVENING...AS WELL AS IN HANDLING OF DRY AIR FEEDING IN FROM THE EAST IN TERMS OF SLOWER WARMING OF SURFACE DEW POINTS/WET BULB TEMPERATURES. ALSO...THESE MODELS PORTRAYED ONLY A VERY FEW HUNDREDTHS OF AN INCH QPF AT MOST BY 15Z...AND EVEN LESS THAN A TENTH OF INCH IN THE FAR NORTH THROUGH 18Z WHERE ABOVE FREEZING TEMPERATURES WILL BE MOST DELAYED. THE 00Z DTX SOUNDING WAS A GOOD FIT TO THE 18Z NAM FORECAST SOUNDING...TOO. QUICK EARLIEST PEEKS AT 00Z NAM/RUC SHOW SIMILAR IDEAS. THUS...NOT INCLINED FOR ANY HEADLINES FOR FREEZING PRECIPITATION AT THIS JUNCTURE...BUT WILL WATCH THE EVOLVING OF THE WEATHER OVERNIGHT FOR POSSIBLE HEADLINES BY RUSH HOUR...IF NEEDED. && .AVIATION...ISSUED 659 PM EST MON 00Z TAFS STARTING OUT VERY BENIGN...WITH VERY FEW CLOUDS EVEN. LATEST MODELS PORTRAY RIDGE EAST OF AREA SLOWLY RETREATING EAST. DRY EASTERLY FLOW PAST SEVERAL HOURS CONTINUES TO COMBAT MOISTENING TREND FROM THE EVOLVING LOW JUST TO THE SOUTHWEST...AND THIS IS LIKELY TO BE THE CASE OVERNIGHT AND INTO TUESDAY...WITH SLOW TO RISE LOW LEVEL DEW POINTS/WET BULB TEMPERATURES HELPING CHANCES FOR FREEZING DRIZZLE/FREEZING RAIN...IF PRECIPITATION DOES OCCUR. LATEST MODEL CONSENSUS IS THAT THE PRECIPITATION WILL LARGELY OCCUR AFTER IT WARMS ENOUGH FOR PROBABLE NON FREEZING PRECIPITATION TYPE...BUT IS STILL POSSIBLE FOR SEVERAL HOURS OF ONSET LIGHTER FREEZING VARIETY...WHICH CONDITIONS ARE INCORPORATED INTO TAFS INTO THE MORNING AFTER 11Z. AS IN PREVIOUS TAFS...HAVE LOWERED CEILINGS OVERNIGHT INTO MVFR CATEGORY BY AROUND MIDNIGHT OR SO. THEN STEADILY DOWNHILL CONDITIONS TUESDAY FORENOON INTO IFR...BOTH RESPECT TO CEILINGS AND VISIBILITIES...CONTINUING IFR AND RAINY ON THROUGH THE AFTERNOON. FOR ALL TAFS...HAVE ALSO INCLUDED A LOW LEVEL WIND SHEAR GROUP TUESDAY MORNING THROUGH MID DAY...WITH STRONGLY VEERING WINDS AND SPEED SHEAR AS WELL. && .SHORT TERM...TONIGHT AND TUESDAY...ISSUED 343 PM EST MON AN INTERESTING AND EQUALLY CHALLENGING FORECAST TONIGHT INTO TUESDAY MORNING. WATER VAPOR LOOP REVEALS TROUGH HAS JUST MOVED OUT INTO THE WESTERN HIGH PLAINS WITH THE BASE OF THIS TROUGH ROUNDING OUT THROUGH NEW MEXICO THIS AFTERNOON. UPSTREAM WIND PROFILER NETWORK SHOWS A 130-140KT 300MB JET INTERACTING WITH SUBTROPICAL MOISTURE FROM THE PACIFIC THAT IS CURRENTLY RESULTING IN PRECIP DEVELOPMENT ACROSS ARKLATEX REGION WITH RADAR RETURNS ACROSS MISSOURI NOT REACHING THE GROUND (VIRGA). SURFACE WARM FRONT WAS ANALYZED ACROSS CENTRAL IL/IN/OH FROM MAIN SURFACE LOW NEAR PITTSFIELD ILLINOIS. TO OUR NORTHEAST WAS A LARGE SURFACE HIGH OF 1025MB OVER JAMES BAY WHERE DEWPOINTS ACROSS LOWER ONTARIO WERE IN THE SINGLE DIGITS AND MID TEENS. SO THE POTENTIAL FOR A WINTRY MESS IS SETTING UP ACROSS SOUTHEAST LOWER MICHIGAN LATE TONIGHT INTO TUESDAY MORNING IN THE FORM OF FREEZING RAIN. 12Z NUMERICAL SUITE INITIALIZED A COUPLE OF DEGREES TOO WARM AND A QUICK LOOK AT THE 18Z NAM SUGGESTS THIS WITH NEAR SURFACE WET BULB AND DEWPOINT TEMPS DROPPING ANOTHER DEGREE IN THE NUMERICAL RUN. AS SYSTEM DEEPENS UPSTREAM...AGEOSTROPHIC FLOW INCREASES AS WELL WHICH POINTS FROM NORTHWEST PA (STREAMLINE ANALYSIS) AND ACROSS LOWER ONTARIO. THIS POINTS TOWARD LOWER SURFACE DEWPOINTS/DRIER AIR FILTERING INTO SOUTHEAST LOWER AS ABUNDANT MOISTURE TRANSPORT DEVELOPS ALOFT EMBEDDED WITHIN THE LOW LEVEL JET AXIS. WITH AMPLE BREAKS IN THE MID AND HIGH LEVEL CLOUDINESS SEEN IN THE 1 KM VISIBLE IMAGERY AND OUR ALREADY LOW DEWPOINTS...WE COULD SEE A BRIEF PERIOD OF THIS EVENING OF DECENT COOLING BEFORE THE THICKER CLOUDS ARRIVE OVERNIGHT. HOWEVER...WITH THAT SAID...OUR EASTERLY GRADIENT WILL BE INCREASING AS WELL HELPING TO DRIVE THAT DRIER AIRMASS UPSTREAM TO FILTER INTO THE LOCAL AREA. WET BULB PROFILES BECOME INCREASINGLY MORE INTERESTING AS NEAR THE GROUND (SFC-950MB) WE ARE EXPECTING TEMPS TO REMAIN BELOW FREEZING OVERNIGHT INTO TUESDAY MORNING...ESPECIALLY ALONG AND NORTH OF M59. THE RUC13 HAS DONE MUCH BETTER WITH SURFACE DEWPOINTS WHICH SUGGESTS A PROLONGED PERIOD OF NEAR FREEZING TEMPS ACROSS THE TRI CITIES. QPF AMOUNTS ARE LIGHT OVERNIGHT WITH MOST OF THE QPF JUST SOUTH OF M59 (0.01-0.05") BUT AMPLE SHEAR TOP OF THE MOISTURE COLUMN OVERNIGHT COULD PROVIDE THE CHANCE FOR LIGHT PRECIP (DRIZZLE) ACROSS ALL OF SOUTHEAST LOWER. DURING TUESDAY MORNING...STILL AMPLE OPPORTUNITY FOR MORE FREEZING RAIN NORTH OF M59 WITH AGEOSTROPHIC FLOW STILL COMING FROM LOWER ONTARIO AND IMPRESSIVE MOISTURE TRANSPORT ADVECTING NORTH ALOFT. PRECIP IS EXPECTED TO EXPAND ACROSS ALL OF THE REGION QUICKLY AS SURFACE LOW DEEPENS TOWARD 990MB LATE IN THE DAY. THIS LOW BASED ON UPSTREAM PRESSURE FALLS AND PARALLEL PROFILERS UPSTREAM SHOULD TRACK NORTHWARD ACROSS THE DETROIT AND ST CLAIR RIVERS LATE IN THE DAY WHICH PROVIDES US WITH MAINLY RAIN FOR THE CWA BY NOON. THE EXCEPTION WOULD BE MIDLAND AND PERHAPS BAY COUNTY WERE WE WILL KEEP THE MIX OF RAIN/FZRA IN THE FORECAST AT THIS TIME. QPF TOTALS FOR THE DAY COULD EXCEED HALF AN INCH SO OUR CONCERN IS IF THE COLDER AIR DOES HANG ON LONGER...WE WILL NEED TO LOOK AT HEADLINES. AT THIS TIME...WE WILL STRONGLY WORD THE HWO AND OUR FORECAST AND EVENING SHIFT WILL HAVE OPPORTUNITY TO LOOK AT CURRENT TEMPS AND 00Z MODEL GUIDANCE (NOT TO MENTION PRECIP DEVELOPING UPSTREAM) BEFORE MAKING DECISIONS. AS FOR TEMPS...WITH AMPLE BREAKS UPSTREAM IN THE CLOUD FIELD AND LOWER DEWPOINTS ADVECTING INTO THE REGION...WE WILL LOWER TEMPS A GOOD 3-5 DEGREES FROM MOS. AND WITH TUESDAY WITH WET PROCESS WELL UNDERWAY...TEMPERATURES WILL HOLD TO AROUND 40 SOUTHEAST AND LOW-MID 30S NORTH AND WEST BASED ON THE LATEST SURFACE LOW FORECAST TRACK. && .LONG TERM...TUESDAY NIGHT THROUGH MONDAY...ISSUED 343 PM EST MON THE TRANSITION FROM RAIN TO SNOW WILL BE THE FIRST PROBLEM TO DEAL WITH TUESDAY NIGHT INTO WEDNESDAY MORNING IN SE MICHIGAN. THE PACE OF TRANSITION AND POTENTIAL ACCUMULATION WILL DEPEND A LOT ON THE CHARACTER OF THE SURFACE PRESSURE PATTERN, OF WHICH THERE ARE STILL SOME CHOICES. DIFFERENCES ARE NOT HUGE IN THE OVERALL SCENARIO BUT THERE ARE PREFERENCES AMONG THE 12Z MODEL SOLUTIONS. DPROG/DT AROUND 00Z WEDNESDAY SHOWS A BIT OF A SHIFT AWAY FROM SURFACE LOW CONSOLIDATION IN THE MODELS BUT THEY HOLD ON TO A TENDENCY FOR THE UPPER TROF TO TAKE ON SOME NEGATIVE TILT. THIS UPPER AIR TENDENCY LOOKS JUSTIFIED BASED ON THE STRUCTURE OF THE UPPER JET WITH SO MUCH ENERGY ON THE DOWNSTREAM SIDE OF THE TROF AXIS. AT THE SAME TIME, THERE IS NOT ENOUGH FLOW ON THE UPSTREAM SIDE OF THE TROF TO JUSTIFY THE CLOSED CONTOURS IN THE GFS AT 500 MB. PREFER THE FULL LATITUDE LOOK OF THE NAM WITH SUPPORT FROM THE CANADIAN AND DTX WRFXX, AND EARLIER RUNS OF THE EURO MODELS. AGAIN, THE DIFFERENCES DO NOT IMPACT THE TRANSITION FROM RAIN TO SNOW AS MUCH AS QPF. THE TRANSITION IS STILL ON TRACK FOR TUESDAY EVENING FOLLOWED BY ALL SNOW OVERNIGHT INTO WEDNESDAY MORNING. THE GFS SOLUTION OFFERS HIGHER QPF WITH DEVELOPMENT OF STRONGER MID LEVEL DEFORMATION BY 12Z WEDNESDAY. WE THINK THE DEFORMATION WILL BE THERE BUT NOT AS STRONG AS THE GFS. EXPECT AN INCH OR TWO OF WET SNOW ACCUMULATION BY SUNRISE WEDNESDAY MORNING WITH CHANCE POPS LINGERING INTO THE DAYTIME. THE PROGRESSIVE NATURE OF THE LARGE SCALE PATTERN GETS THIS SYSTEM OUT OF THE GREAT LAKES BY WEDNESDAY NIGHT. HIGH PRESSURE WILL MOVE IN AND OUT QUICKLY BY THURSDAY AS YET ANOTHER WAVE MOVES INTO THE REGION, BUT THIS TIME FROM CENTRAL CANADA. INDICATIONS OF MODEST SPLIT FLOW DEVELOPMENT CONTINUE TO BE SHOWN IN THE MODELS ON THURSDAY WITH THE NORTHERN WAVE BRINGING A SURFACE LOW TO AROUND IOWA SOUTHERN MINNESOTA. WARM ADVECTION AHEAD OF THIS SYSTEM WILL KEEP A CHANCE OF RAIN AND SNOW IN THE FORECAST. THE COLD FRONT TRAILING THE THURSDAY SYSTEM WILL ENCOUNTER SOME RESISTANCE TO EASTWARD PROGRESS ON FRIDAY. THE MAJORITY OF MODEL SOLUTIONS INDICATE THAT IT WILL STALL OVER SE MICHIGAN, OR JUST TO OUR EAST, UNDER STRONG SW FLOW ALOFT. THE 00Z GFS WAS THE FARTHEST EAST SHOWING THE BOUNDARY ALONG A LINE FROM INDY TO CLEVELAND BY 00Z SATURDAY. THE 12Z RUN IS EVEN SLOWER. SINCE THESE DEVELOPMENTS LOOK PRETTY SOLID, ESPECIALLY AS THE NEXT SOUTHERN PLAINS SYSTEM GATHERS ITSELF DURING THIS TIME, WE WILL CARRY A CHANCE OF RAIN AND SNOW INTO FRIDAY BASED ON GFS THICKNESS FORECASTS. MODEL AGREEMENT IS VERY GOOD REGARDING THE TRACK OF THE SOUTHERN PLAINS SYSTEM INTO THE OHIO VALLEY ON SATURDAY, ESPECIALLY BETWEEN THE GFS AND ECMWF. THERE ARE SOME STRENGTH DIFFERENCES BUT GOOD AGREEMENT ON THE TRACK OF THE SYSTEM GENERALLY ALONG AN INDY TO CLEVELAND LINE, ALONG THE STALLED FRONT FROM FRIDAY. THE GFS IS THE STRONGEST SOLUTION IN TERMS OF THE SURFACE LOW AND WITH ALARMINGLY HIGH QPF APPROACHING 1 INCH LIQUID BY 00Z SUNDAY. THIS IS PARTIALLY DUE TO THE SYSTEM BEING WARM BUT THE TRACK IS TO OUR SOUTH, SO WE WILL CONFINE THE MENTION OF MIXED PRECIP FROM DETROIT TO THE OHIO BORDER. OVERALL, THE LARGE SCALE PATTERN FAVORS THE GFS BUT A LOT CAN CHANGE BETWEEN NOW AND THEN, WHICH SUGGESTS HOLDING OFF ON A STRONGER MENTION OF SNOW ACCUMULATION IN THE HWO FOR ANOTHER COUPLE OF FORECAST CYCLES. CONTINUED HEIGHT FALLS OVER THE NORTH PACIFIC AND GULF OF AK WILL KEEP THINGS MOVING ALONG ON SUNDAY AND MONDAY. PREFER TO KEEP THINGS DRY BOTH DAYS AS A WEAK WAVE TRACKS WELL TO OUR NORTH THROUGH CANADA ON SUNDAY. EXPECT HIGH PRESSURE TO THEN BE IN PLACE AROUND MONDAY OF NEXT WEEK. THIS PLACES MORE EMPHASIS ON THE LARGE SCALE PATTERN IN THE FORECAST WHICH SHOWS A STRONGER WAVE MOVING INTO THE ROCKIES BY THEN WITH A RIDGE OVER THE GREAT LAKES. STARTED TEMPERATURES OFF A FEW DEGREES BELOW GUIDANCE BUT STILL ABOVE NORMAL BY JANUARY STANDARDS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ462-LHZ463-LHZ464...UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY...LHZ421 AND NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422...UNTIL 7 PM WEDNESDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ460...UNTIL 7 PM WEDNESDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444...UNTIL 7 PM WEDNESDAY. && $$ AVIATION...DWD SHORT TERM...BGM LONG TERM....BT 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 936 PM EST MON JAN 16 2006 .UPDATE...THE SOUNDING AT KAPX SHOWED A RATHER DRY LAYER JUST ABOVE THE SFC. COMPARING THE SOUNDING WITH THE MODEL SOUNDINGS, THE ETA AND RUC LOOK TO BE THE BEST FIT. LOOKING AT THE 18Z ETA AND RUC, THE TIMING WOULD BE A BIT SLOWER THAN WE CURRENTLY HAVE IN THE GRIDS. SO HAVE CUT BACK THE AREAL EXTENT OVERNIGHT FOR THE CHANCE OF PRECIPITATION, ALLOWING FOR THE CHANCES TO BE IN E UPPER AND NE LOWER UNTIL LATE OVERNIGHT. THE 00Z ETA IS CUTTING BACK THE PRECIPITATION EVEN MORE, AS WELL. OTHERWISE, HAVE ADJUSTED WINDS AND HOURLY TEMPERATURES AS THE WINDS HAVE DIED DOWN A BIT MORE THAN WHAT WE HAD IN THE GRIDS. LUTZ && .PREV DISCUSSION...ISSUED 440 PM EST MON JAN 16 2006 NARROW LINE OF MID LEVEL CLOUD COVER CONTINUES TO LIFT THROUGH THE NE PORTION OF THE CWA ALONG A 700 MB TROUGH AXIS. ASSOCIATED SPOTTY (CONVECTIVE) ELEVATED RADAR ECHOS ALSO LIFTING THROUGH THE AREA WITH THE BEST RETURNS HEADING THROUGH UPPER MICHIGAN...WHERE A BRIEF SNOW SHOWER OR FLURRIES MAY STILL OCCUR. OTHERWISE...CLR-PARTLY CLOUDY SKIES AND BREEZY CONDITIONS PREVAIL ACROSS THE MAJORITY OF THE CWA. ONCE AGAIN...A COMPLEX WEATHER SCENARIO SHAPING UP FOR THE NEXT 24 TO 48 HOURS AS THE NORTHERN AND SOUTHERN STREAMS TRY TO PHASE OVER THE WESTERN GREAT LAKES...AND A FAIRLY VIGOROUS WAVE LIFTS UP THROUGH THE REGION. AND ONCE AGAIN WE FIND OURSELVES CONTENDING WITH PRECIP TYPE ISSUES AS WELL AS SNOW ACCUMULATIONS. NAM/GFS80 ARE FAIRLY SIMILAR WITH THE STRENGTH AND TRACK OF THIS SYSTEM ALTHOUGH SOME SUBTLE BUT IMPORTANT DIFFERENCES REMAIN IN THE MODEL THERMAL FIELDS (NAM THE WARMEST AS USUAL). HAVE COME TO TRUST THE GFS THE MOST IN THIS REGARD ESPECIALLY IN A DEVELOPING STORM SYSTEM...AND WILL FOLLOW THIS SOLUTION THE CLOSEST. TONIGHT...OBVIOUS EASIEST PORTION OF THE FORECAST IS THIS EVENING AS PARTLY-MOSTLY CLOUDY SKIES AND DRY CONDITIONS EXPECTED TO PREVAIL. STILL SOME OF THE CONVECTIVE MID CLOUD STUFF WORKING THROUGH EASTERN UPPER MICHIGAN...BUT RADAR EXTRAPOLATION SUGGESTS THIS WILL CLEAR THE AREA BEFORE 6 PM (OFFICIAL START OF THE TONIGHT FORECAST PERIOD). HENCE HAVE NOT INCLUDED ANY PRECIP CHANCES FOR THE EVENING HOURS WITH THE FORECAST ISSUANCE. THEN...ATTENTION TURNS TO PRECIP CHANCES OVERNIGHT AHEAD OF APPROACHING SOUTHERN STREAM WAVE AND INCREASING WARM ADVECTION. BOTH THE NAM/GFS80 MODEL SOUNDINGS FORECAST RAPID MOISTENING COMMENCING LATE OVERNIGHT AS THE SYNOPTIC FORCING INCREASES. HOWEVER...DEEPEST MOISTURE REMAINS CONFINED BY AND LARGE BLO 800 MB AND WARMER THAN -5C WITH THE EXCEPTION OF E UPPER MICHIGAN...SUGGESTING ANY PRECIP THAT GETS GOING LATE WILL COME PRIMARILY IN THE FORM OF FREEZING DRIZZLE...AND HAVE ADDED THIS TO THE FORECAST FOR ALL OF NRN LOWER MICHIGAN. TUESDAY...PRECIP GETS CRANKING ACROSS THE ENTIRE CWA DURING THE MORNING HOURS...COURTESY OF MOISTURE SURGE COMING OUT OF THE GULF/STRONG SHOT OF ISENTROPIC ASCENT/AND UPPER DIVERGENCE MAX LIFTING UP THROUGH THE STATE WITH THE UPPER JET. APPEARS THAT CATEGORICAL POPS ARE IN ORDER FOR THE ENTIRE CWA. QUESTION IS...WHAT WILL THE PRECIP BE? LAST COUPLE OF GFS RUNS (THE MODEL OF CHOICE) SUGGESTING THE WARM NOSE OF AIR (>0C) DEVELOPS AND PUSHES UP THROUGH THE SE PORTION OF THE CWA WITH THE MODEL SOUNDINGS SUPPORTING MORE SLEET OR FREEZING RAIN ACROSS THIS AREA (SFC TEMPS WILL BE BLO FREEZING THROUGH THE MORNING). ICE ACCUMULATIONS OF ONE TO TWO TENTHS OF AN INCH A GOOD POSSIBILITY ACROSS THIS AREA BEFORE A CHANGEOVER TO RAIN AND SNOW DURING THE AFTERNOON HOURS AS COOLER AIR ALOFT COLLAPSES BACK INTO THE REGION. FOR EVERYONE ELSE...HAVE GONE PRIMARILY SNOW THROUGHOUT THE DAY WITH SOME SLEET POSSIBILITIES IN NRN LOWER MICHIGAN...AND SNOW ACCUMULATIONS RUNNING IN THE 2 TO 4 INCH RANGE (FOLLOWED BY A COUPLE MORE INCHES TUESDAY NIGHT...SEE BELOW). ALL IN ALL...SERIOUSLY CONSIDERED GOING AHEAD AND HOISTING APPROPRIATE SECOND AND THIRD PERIOD ADVISORIES TO COVER THIS EVENT. BUT GIVEN THAT THIS SYSTEM IS ONLY NOW COMING OUT OF TEXAS...WILL NOT JUMP THE GUN. WILL WAIT FOR THE 00Z RAOB DATA TO GET A GOOD FIX ON THIS SYSTEM AND THE USUALLY MORE RELIABLE 00Z MODEL DATA BEFORE COMMITTING TO ANY HEADLINES. WILL CONTINUE TO STRONGLY HIGHLIGHT THESE HAZARDS IN THE HAZARDOUS WEATHER OUTLOOK. ADAM TUESDAY NIGHT AND WEDNESDAY...UPPER TROUGH DIGGING INTO IN THE MISSISSIPPI RIVER VALLEY WILL SLIDE ACROSS NRN MICHIGAN WEDNESDAY MORNING...AND BECOMES SLIGHTLY NEGATIVELY TILTED. STRONG H3-H2 LAYER DIVERGENCE DEVELOPS OVER THE AREA...WHILE THE SFC LOW CONTINUES TO DEEPEN. COPIOUS H8-H5 MOISTURE WRAPS AROUND THE BACKSIDE OF THE SFC LOW IN DEVELOPING DEFORMATION ZONE...WHICH AT THIS TIME IS PEGGED FOR RIGHT OVER NRN MICHIGAN. THIS SYSTEM HAS YET TO GET UNDERWAY IN IT'S DEVELOPMENT...SO EXACT DETAILS AS FAR AS THE THERMAL PROFILE AND SYSTEM DYNAMICAL FORCING (WHICH WILL HAVE A SIGNIFICANT IMPACT ON THE AMOUNT OF PRECIP/SNOW)...AND ARE TOO DIFFICULT TO DETERMINE AT THIS TIME. HOWEVER...CAN SAY THAT THAT CURRENT FORECAST IS NOT TOO BAD OVERALL...WITH CATEGORICAL PRECIP CHANCES FOR ALL BUT MAYBE THE FAR SW COUNTIES WHERE PRECIP STILL REMAINS LIKELY. LOOK FOR SNOW TO BE MORE ALIGNED ALONG AND AHEAD OF THE SFC TROUGH AXIS IN DEPARTING ISENTROPIC ASCENT. THEN...AS SYSTEM DEEPENS THROUGH WEDNESDAY NIGHT PRECIP WILL BE ENHANCED ON THE BACKSIDE OF THE LOW IN DEFORMATION ZONE. THERMALLY...COLD ADVECTION WILL ALREADY BE DEEP ENOUGH ACROSS MOST OF NRN MICHIGAN FOR AN ALL SNOW FORECAST. STILL A THIN LAYER OF AIR (WITH SOME UNCERTAINTY TO THE DEPTH/AND MAX T) RIGHT NEAR THE THUMB FROM THE SFC TO 850MB. MAX TEMP ONLY 1C...SO EVEN THIS AREA COULD BE ALL SNOW...BUT WILL RIDE A RAIN/SNOW MIX FOR THE FIRST FEW HOURS OF THE EVENING. QPF FORECASTS SUGGEST AROUND 0.25"...BUT COULD SEE MORE WITH THIS SYSTEM DEEPENING. A RATHER WET SNOW WITH LIQUID/SNOW RATIOS AROUND 9:1...GIVING A CONSERVATIVE 2" SNOW AMOUNT FORECAST. EXPECT UPDATES TO THE FORECAST SNOW AMOUNTS IN THIS TYPE OF DEVELOPING SYSTEM. GFS IS SLOWER IN SHIFTING THIS SYSTEM EAST WHILE THE 18Z NAM HAS JUMPED MORE IN LINE WITH THIS IDEA AS OF THE 18Z RUN. BOTH SUGGEST THAT IT MAY BE DIFFICULT TO DEVELOP LAKE EFFECT SNOW SHOWERS LATE TOMORROW NIGHT...WITH H8 TEMPS TO -8C OR SO OFF LAKE MICHIGAN IN INCREASING NW FLOW. H9-H7 RH IS DEFINITELY THERE AT THIS TIME (>90%)...AND DELTA T'S WILL BE MARGINAL AT 13-14C. INVERSION HEIGHTS TO 4500 FEET SHOULD AT LEAST BE ABLE TO RETAIN THE CHANCE FOR SNOW SHOWER BY DAYBREAK. SLIGHTLY BETTER LAKE EFFECT PARAMETERS IN STORE FOR WEDNESDAY MORNING (DELTA T'S BECOMING SUFFICIENT/INVERSION HEIGHTS MAYBE AS HIGH AS 5KFT AS WEAK WAVE EXPECTED TO ROLL BY IN THE MORNING)...BUT MOISTURE WILL ALREADY BE TRYING TO PULL OUT TO THE EAST. BEST CHANCES FOR ACCUMULATING SNOW IN THE NW FLOW AREA OF EASTERN UPPER AND NW FLOW REGIMES AGAINST THE HIGHER TERRAIN OF NRN LOWER...BUT DO NOT EXPECT ANY MORE THAN 1 OR 2 INCHES IN THESE AREAS...WITH LESS ELSEWHERE. LOOK FOR SOME GUSTY NW WINDS WEDNESDAY...WITH 25-30MPH GUSTS BEING RATHER COMMON. TEMPS SHOULD NOT CLIMB TOO MUCH FROM TUESDAY NIGHT LOWS IN THE LOWER/MID 20S. CAA THROUGH THE DAY WILL KEEP HIGHS IN THE 25-30 RANGE. WEDNESDAY NIGHT...WILL KEEP THINGS PRECIP-FREE HERE. WAA ENSUES THROUGH THE NIGHT IN MORE WESTERLY FLOW. THERMALLY....H8 TEMPS ARE -10C TO -12C IN THE EVENING WITH MOISTURE DOWN TO <50%. COULD SEE SOME EVENING SCATTERED LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES AND THIS MAY HAVE TO BE ADDED INTO LATER FORECASTS...BUT FOR NOW WILL KEEP IT OUT. BY 06Z CONTINUED WARMING TO -3C TO -5C SHOULD SHUT THINGS OFF EXCEPT FOR SOME LAKE CLOUDS ACROSS SW FLOW REGIMES WHILE WINDS CONTINUE TO BACK IN WAA. WINDS INCREASE JUST OFF THE SFC TO 25 KNOTS...BUT AM EXPECTING BL TEMPS TO LOWER INTO THE MID TEENS TO AROUND 20F FOR A CHILLIER NIGHT. THURSDAY AND THURSDAY NIGHT...WEAK SHORTWAVE STILL FORECAST TO EJECT ACROSS WESTERN LAKE SUPERIOR BY THURSDAY EVENING WITH WARM FRONT DRAPED ACROSS EASTERN UPPER. WILL KEEP CHANCES FOR SNOW GOING IN THIS PERIOD...BUT THIS SYSTEM STILL LOOKS RATHER WIMPY. TEMPS SHOULD REBOUND INTO THE LOWER AND MIDDLE 30S...MAYBE COOLER FOR THOSE AREAS IN SSW FLOW REGIMES...THAT CANNOT GET OUT OF THE LAKE CLOUDS FROM SHALLOW INSTABILITY OVER THE LAKES. FRIDAY THROUGH MONDAY...NO COLD AIR IN SIGHT. SW FLOW ALOFT AND H8 TEMPS IN THE SINGLE DIGITS BELOW ZERO...POTENTIALLY COOLING TO -10C OR COLDER BY THE START OF NEXT WORK WEEK. ALL EXTENDED MODELS ARE IN DECENT AGREEMENT WITH THE OVERALL UPPER LEVEL FLOW PATTERN...AND SHOW THE SW FLOW ALOFT BREAKING DOWN TEMPORARILY THROUGH THIS PERIOD WITH THE ARRIVAL OF A FEW SHORTWAVES. THE FIRST WAVE WILL BE THE ONE ASSOCIATED WITH THE CHANCE OF SNOW THURSDAY. THE SECOND...AND STRONGER LOOKING WAVE HAS BEEN SLOWED...AND NOW EXPECTED TO ARRIVE SATURDAY. THIS SYSTEM IS SHOWING THE CAPABILITY OF PRODUCING BETTER ACCUMULATING SNOW. THE FINAL WAVE ARRIVES LATE SUNDAY NIGHT/MONDAY TIMEFRAME AND SUGGEST THAT WE MIGHT GET A BRIEF SHOT OF THE COLDER ARCTIC AIR THAT HAS BEEN LOCKED UP TO OUR NORTH OVER THE PAST SEVERAL WEEKS. ALREADY SEEING STRONG RIDGING IN THE ROCKIES BEHIND THIS FINAL WAVE...INDICATING THE POSSIBILITY OF WARMER AIR TO AGAIN SPREAD BACK INTO NRN MICHIGAN. WILL KEEP CHANCES FOR RAIN AND SNOW SHOWERS THURSDAY AND THURSDAY NIGHT (BETTER CHANCES FOR SNOW IN THE HIGHER TERRAIN OF NRN LOWER...AND ALL OF EASTERN UPPER AT THIS POINT). ALTHOUGH TIMING ISSUES WILL MORE THAN LIKELY ARISE...WILL KEEP FRIDAY/FRIDAY NIGHT PRECIP-FREE. SATURDAY AND SATURDAY NIGHT ARE PINPOINTED FOR THE CHANCE OF BETTER ACCUMULATING SNOWS (WET SNOW) AND THEN WILL KEEP THINGS PRECIP FREE FOR THE REMAINDER OF THE PERIOD AS THE PATTERN IS NOT CONDUCIVE TO OUR NORMALLY HIGH CLIMATOLOGICAL CHANCES FOR PRECIP (JUST NOT COLD ENOUGH TO GENERATE LAKE EFFECT). TEMPERATURES THROUGH THE PERIOD WILL HAVE HIGHS IN THE LOW TO MIDDLE 30S WITH MINIMUM TEMPS IN THE UPPER TEENS AND 20S. SMD && .APX...WATCHES/WARNINGS/ADVISORIES...NONE && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 659 PM EST MON JAN 16 2006 .AVIATION... 00Z TAFS STARTING OUT VERY BENIGN...WITH VERY FEW CLOUDS EVEN. LATEST MODELS PORTRAY RIDGE EAST OF AREA SLOWLY RETREATING EAST. DRY EASTERLY FLOW PAST SEVERAL HOURS CONTINUES TO COMBAT MOISTENING TREND FROM THE EVOLVING LOW JUST TO THE SOUTHWEST...AND THIS IS LIKELY TO BE THE CASE OVERNIGHT AND INTO TUESDAY...WITH SLOW TO RISE LOW LEVEL DEW POINTS/WET BULB TEMPERATURES HELPING CHANCES FOR FREEZING DRIZZLE/FREEZING RAIN...IF PRECIPITATION DOES OCCUR. LATEST MODEL CONSENSUS IS THAT THE PRECIPITATION WILL LARGELY OCCUR AFTER IT WARMS ENOUGH FOR PROBABLE NON FREEZING PRECIPITATION TYPE...BUT IS STILL POSSIBLE FOR SEVERAL HOURS OF ONSET LIGHTER FREEZING VARIETY...WHICH CONDITIONS ARE INCORPORATED INTO TAFS INTO THE MORNING AFTER 11Z. AS IN PREVIOUS TAFS...HAVE LOWERED CEILINGS OVERNIGHT INTO MVFR CATEGORY BY AROUND MIDNIGHT OR SO. THEN STEADILY DOWNHILL CONDITIONS TUESDAY FORENOON INTO IFR...BOTH RESPECT TO CEILINGS AND VISIBILITIES...CONTINUING IFR AND RAINY ON THROUGH THE AFTERNOON. FOR ALL TAFS...HAVE ALSO INCLUDED A LOW LEVEL WIND SHEAR GROUP TUESDAY MORNING THROUGH MID DAY...WITH STRONGLY VEERING WINDS AND SPEED SHEAR AS WELL. && .SHORT TERM...TONIGHT AND TUESDAY...ISSUED 343 PM EST MON AN INTERESTING AND EQUALLY CHALLENGING FORECAST TONIGHT INTO TUESDAY MORNING. WATER VAPOR LOOP REVEALS TROUGH HAS JUST MOVED OUT INTO THE WESTERN HIGH PLAINS WITH THE BASE OF THIS TROUGH ROUNDING OUT THROUGH NEW MEXICO THIS AFTERNOON. UPSTREAM WIND PROFILER NETWORK SHOWS A 130-140KT 300MB JET INTERACTING WITH SUBTROPICAL MOISTURE FROM THE PACIFIC THAT IS CURRENTLY RESULTING IN PRECIP DEVELOPMENT ACROSS ARKLATEX REGION WITH RADAR RETURNS ACROSS MISSOURI NOT REACHING THE GROUND (VIRGA). SURFACE WARM FRONT WAS ANALYZED ACROSS CENTRAL IL/IN/OH FROM MAIN SURFACE LOW NEAR PITTSFIELD ILLINOIS. TO OUR NORTHEAST WAS A LARGE SURFACE HIGH OF 1025MB OVER JAMES BAY WHERE DEWPOINTS ACROSS LOWER ONTARIO WERE IN THE SINGLE DIGITS AND MID TEENS. SO THE POTENTIAL FOR A WINTRY MESS IS SETTING UP ACROSS SOUTHEAST LOWER MICHIGAN LATE TONIGHT INTO TUESDAY MORNING IN THE FORM OF FREEZING RAIN. 12Z NUMERICAL SUITE INITIALIZED A COUPLE OF DEGREES TOO WARM AND A QUICK LOOK AT THE 18Z NAM SUGGESTS THIS WITH NEAR SURFACE WET BULB AND DEWPOINT TEMPS DROPPING ANOTHER DEGREE IN THE NUMERICAL RUN. AS SYSTEM DEEPENS UPSTREAM...AGEOSTROPHIC FLOW INCREASES AS WELL WHICH POINTS FROM NORTHWEST PA (STREAMLINE ANALYSIS) AND ACROSS LOWER ONTARIO. THIS POINTS TOWARD LOWER SURFACE DEWPOINTS/DRIER AIR FILTERING INTO SOUTHEAST LOWER AS ABUNDANT MOISTURE TRANSPORT DEVELOPS ALOFT EMBEDDED WITHIN THE LOW LEVEL JET AXIS. WITH AMPLE BREAKS IN THE MID AND HIGH LEVEL CLOUDINESS SEEN IN THE 1 KM VISIBLE IMAGERY AND OUR ALREADY LOW DEWPOINTS...WE COULD SEE A BRIEF PERIOD OF THIS EVENING OF DECENT COOLING BEFORE THE THICKER CLOUDS ARRIVE OVERNIGHT. HOWEVER...WITH THAT SAID...OUR EASTERLY GRADIENT WILL BE INCREASING AS WELL HELPING TO DRIVE THAT DRIER AIRMASS UPSTREAM TO FILTER INTO THE LOCAL AREA. WET BULB PROFILES BECOME INCREASINGLY MORE INTERESTING AS NEAR THE GROUND (SFC-950MB) WE ARE EXPECTING TEMPS TO REMAIN BELOW FREEZING OVERNIGHT INTO TUESDAY MORNING...ESPECIALLY ALONG AND NORTH OF M59. THE RUC13 HAS DONE MUCH BETTER WITH SURFACE DEWPOINTS WHICH SUGGESTS A PROLONGED PERIOD OF NEAR FREEZING TEMPS ACROSS THE TRI CITIES. QPF AMOUNTS ARE LIGHT OVERNIGHT WITH MOST OF THE QPF JUST SOUTH OF M59 (0.01-0.05") BUT AMPLE SHEAR TOP OF THE MOISTURE COLUMN OVERNIGHT COULD PROVIDE THE CHANCE FOR LIGHT PRECIP (DRIZZLE) ACROSS ALL OF SOUTHEAST LOWER. DURING TUESDAY MORNING...STILL AMPLE OPPORTUNITY FOR MORE FREEZING RAIN NORTH OF M59 WITH AGEOSTROPHIC FLOW STILL COMING FROM LOWER ONTARIO AND IMPRESSIVE MOISTURE TRANSPORT ADVECTING NORTH ALOFT. PRECIP IS EXPECTED TO EXPAND ACROSS ALL OF THE REGION QUICKLY AS SURFACE LOW DEEPENS TOWARD 990MB LATE IN THE DAY. THIS LOW BASED ON UPSTREAM PRESSURE FALLS AND PARALLEL PROFILERS UPSTREAM SHOULD TRACK NORTHWARD ACROSS THE DETROIT AND ST CLAIR RIVERS LATE IN THE DAY WHICH PROVIDES US WITH MAINLY RAIN FOR THE CWA BY NOON. THE EXCEPTION WOULD BE MIDLAND AND PERHAPS BAY COUNTY WERE WE WILL KEEP THE MIX OF RAIN/FZRA IN THE FORECAST AT THIS TIME. QPF TOTALS FOR THE DAY COULD EXCEED HALF AN INCH SO OUR CONCERN IS IF THE COLDER AIR DOES HANG ON LONGER...WE WILL NEED TO LOOK AT HEADLINES. AT THIS TIME...WE WILL STRONGLY WORD THE HWO AND OUR FORECAST AND EVENING SHIFT WILL HAVE OPPORTUNITY TO LOOK AT CURRENT TEMPS AND 00Z MODEL GUIDANCE (NOT TO MENTION PRECIP DEVELOPING UPSTREAM) BEFORE MAKING DECISIONS. AS FOR TEMPS...WITH AMPLE BREAKS UPSTREAM IN THE CLOUD FIELD AND LOWER DEWPOINTS ADVECTING INTO THE REGION...WE WILL LOWER TEMPS A GOOD 3-5 DEGREES FROM MOS. AND WITH TUESDAY WITH WET PROCESS WELL UNDERWAY...TEMPERATURES WILL HOLD TO AROUND 40 SOUTHEAST AND LOW-MID 30S NORTH AND WEST BASED ON THE LATEST SURFACE LOW FORECAST TRACK. && .LONG TERM...TUESDAY NIGHT THROUGH MONDAY...ISSUED 343 PM EST MON THE TRANSITION FROM RAIN TO SNOW WILL BE THE FIRST PROBLEM TO DEAL WITH TUESDAY NIGHT INTO WEDNESDAY MORNING IN SE MICHIGAN. THE PACE OF TRANSITION AND POTENTIAL ACCUMULATION WILL DEPEND A LOT ON THE CHARACTER OF THE SURFACE PRESSURE PATTERN, OF WHICH THERE ARE STILL SOME CHOICES. DIFFERENCES ARE NOT HUGE IN THE OVERALL SCENARIO BUT THERE ARE PREFERENCES AMONG THE 12Z MODEL SOLUTIONS. DPROG/DT AROUND 00Z WEDNESDAY SHOWS A BIT OF A SHIFT AWAY FROM SURFACE LOW CONSOLIDATION IN THE MODELS BUT THEY HOLD ON TO A TENDENCY FOR THE UPPER TROF TO TAKE ON SOME NEGATIVE TILT. THIS UPPER AIR TENDENCY LOOKS JUSTIFIED BASED ON THE STRUCTURE OF THE UPPER JET WITH SO MUCH ENERGY ON THE DOWNSTREAM SIDE OF THE TROF AXIS. AT THE SAME TIME, THERE IS NOT ENOUGH FLOW ON THE UPSTREAM SIDE OF THE TROF TO JUSTIFY THE CLOSED CONTOURS IN THE GFS AT 500 MB. PREFER THE FULL LATITUDE LOOK OF THE NAM WITH SUPPORT FROM THE CANADIAN AND DTX WRFXX, AND EARLIER RUNS OF THE EURO MODELS. AGAIN, THE DIFFERENCES DO NOT IMPACT THE TRANSITION FROM RAIN TO SNOW AS MUCH AS QPF. THE TRANSITION IS STILL ON TRACK FOR TUESDAY EVENING FOLLOWED BY ALL SNOW OVERNIGHT INTO WEDNESDAY MORNING. THE GFS SOLUTION OFFERS HIGHER QPF WITH DEVELOPMENT OF STRONGER MID LEVEL DEFORMATION BY 12Z WEDNESDAY. WE THINK THE DEFORMATION WILL BE THERE BUT NOT AS STRONG AS THE GFS. EXPECT AN INCH OR TWO OF WET SNOW ACCUMULATION BY SUNRISE WEDNESDAY MORNING WITH CHANCE POPS LINGERING INTO THE DAYTIME. THE PROGRESSIVE NATURE OF THE LARGE SCALE PATTERN GETS THIS SYSTEM OUT OF THE GREAT LAKES BY WEDNESDAY NIGHT. HIGH PRESSURE WILL MOVE IN AND OUT QUICKLY BY THURSDAY AS YET ANOTHER WAVE MOVES INTO THE REGION, BUT THIS TIME FROM CENTRAL CANADA. INDICATIONS OF MODEST SPLIT FLOW DEVELOPMENT CONTINUE TO BE SHOWN IN THE MODELS ON THURSDAY WITH THE NORTHERN WAVE BRINGING A SURFACE LOW TO AROUND IOWA SOUTHERN MINNESOTA. WARM ADVECTION AHEAD OF THIS SYSTEM WILL KEEP A CHANCE OF RAIN AND SNOW IN THE FORECAST. THE COLD FRONT TRAILING THE THURSDAY SYSTEM WILL ENCOUNTER SOME RESISTANCE TO EASTWARD PROGRESS ON FRIDAY. THE MAJORITY OF MODEL SOLUTIONS INDICATE THAT IT WILL STALL OVER SE MICHIGAN, OR JUST TO OUR EAST, UNDER STRONG SW FLOW ALOFT. THE 00Z GFS WAS THE FARTHEST EAST SHOWING THE BOUNDARY ALONG A LINE FROM INDY TO CLEVELAND BY 00Z SATURDAY. THE 12Z RUN IS EVEN SLOWER. SINCE THESE DEVELOPMENTS LOOK PRETTY SOLID, ESPECIALLY AS THE NEXT SOUTHERN PLAINS SYSTEM GATHERS ITSELF DURING THIS TIME, WE WILL CARRY A CHANCE OF RAIN AND SNOW INTO FRIDAY BASED ON GFS THICKNESS FORECASTS. MODEL AGREEMENT IS VERY GOOD REGARDING THE TRACK OF THE SOUTHERN PLAINS SYSTEM INTO THE OHIO VALLEY ON SATURDAY, ESPECIALLY BETWEEN THE GFS AND ECMWF. THERE ARE SOME STRENGTH DIFFERENCES BUT GOOD AGREEMENT ON THE TRACK OF THE SYSTEM GENERALLY ALONG AN INDY TO CLEVELAND LINE, ALONG THE STALLED FRONT FROM FRIDAY. THE GFS IS THE STRONGEST SOLUTION IN TERMS OF THE SURFACE LOW AND WITH ALARMINGLY HIGH QPF APPROACHING 1 INCH LIQUID BY 00Z SUNDAY. THIS IS PARTIALLY DUE TO THE SYSTEM BEING WARM BUT THE TRACK IS TO OUR SOUTH, SO WE WILL CONFINE THE MENTION OF MIXED PRECIP FROM DETROIT TO THE OHIO BORDER. OVERALL, THE LARGE SCALE PATTERN FAVORS THE GFS BUT A LOT CAN CHANGE BETWEEN NOW AND THEN, WHICH SUGGESTS HOLDING OFF ON A STRONGER MENTION OF SNOW ACCUMULATION IN THE HWO FOR ANOTHER COUPLE OF FORECAST CYCLES. CONTINUED HEIGHT FALLS OVER THE NORTH PACIFIC AND GULF OF AK WILL KEEP THINGS MOVING ALONG ON SUNDAY AND MONDAY. PREFER TO KEEP THINGS DRY BOTH DAYS AS A WEAK WAVE TRACKS WELL TO OUR NORTH THROUGH CANADA ON SUNDAY. EXPECT HIGH PRESSURE TO THEN BE IN PLACE AROUND MONDAY OF NEXT WEEK. THIS PLACES MORE EMPHASIS ON THE LARGE SCALE PATTERN IN THE FORECAST WHICH SHOWS A STRONGER WAVE MOVING INTO THE ROCKIES BY THEN WITH A RIDGE OVER THE GREAT LAKES. STARTED TEMPERATURES OFF A FEW DEGREES BELOW GUIDANCE BUT STILL ABOVE NORMAL BY JANUARY STANDARDS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ462-LHZ463-LHZ464...UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY...LHZ421 AND NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422...UNTIL 7 PM WEDNESDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ460...UNTIL 7 PM WEDNESDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444...UNTIL 7 PM WEDNESDAY. && $$ AVIATION...DWD SHORT TERM...BGM LONG TERM....BT 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 DETROIT/PONTIAC MI 343 PM EST MON JAN 16 2006 .SHORT TERM...TONIGHT AND TUESDAY AN INTERESTING AND EQUALLY CHALLENGING FORECAST TONIGHT INTO TUESDAY MORNING. WATER VAPOR LOOP REVEALS TROUGH HAS JUST MOVED OUT INTO THE WESTERN HIGH PLAINS WITH THE BASE OF THIS TROUGH ROUNDING OUT THROUGH NEW MEXICO THIS AFTERNOON. UPSTREAM WIND PROFILER NETWORK SHOWS A 130-140KT 300MB JET INTERACTING WITH SUBTROPICAL MOISTURE FROM THE PACIFIC THAT IS CURRENTLY RESULTING IN PRECIP DEVELOPMENT ACROSS ARKLATEX REGION WITH RADAR RETURNS ACROSS MISSOURI NOT REACHING THE GROUND (VIRGA). SURFACE WARM FRONT WAS ANALYZED ACROSS CENTRAL IL/IN/OH FROM MAIN SURFACE LOW NEAR PITTSFIELD ILLINOIS. TO OUR NORTHEAST WAS A LARGE SURFACE HIGH OF 1025MB OVER JAMES BAY WHERE DEWPOINTS ACROSS LOWER ONTARIO WERE IN THE SINGLE DIGITS AND MID TEENS. SO THE POTENTIAL FOR A WINTRY MESS IS SETTING UP ACROSS SOUTHEAST LOWER MICHIGAN LATE TONIGHT INTO TUESDAY MORNING IN THE FORM OF FREEZING RAIN. 12Z NUMERICAL SUITE INITIALIZED A COUPLE OF DEGREES TOO WARM AND A QUICK LOOK AT THE 18Z NAM SUGGESTS THIS WITH NEAR SURFACE WET BULB AND DEWPOINT TEMPS DROPPING ANOTHER DEGREE IN THE NUMERICAL RUN. AS SYSTEM DEEPENS UPSTREAM...AGEOSTROPHIC FLOW INCREASES AS WELL WHICH POINTS FROM NORTHWEST PA (STREAMLINE ANALYSIS) AND ACROSS LOWER ONTARIO. THIS POINTS TOWARD LOWER SURFACE DEWPOINTS/DRIER AIR FILTERING INTO SOUTHEAST LOWER AS ABUNDANT MOISTURE TRANSPORT DEVELOPS ALOFT EMBEDDED WITHIN THE LOW LEVEL JET AXIS. WITH AMPLE BREAKS IN THE MID AND HIGH LEVEL CLOUDINESS SEEN IN THE 1 KM VISIBLE IMAGERY AND OUR ALREADY LOW DEWPOINTS...WE COULD SEE A BRIEF PERIOD OF THIS EVENING OF DECENT COOLING BEFORE THE THICKER CLOUDS ARRIVE OVERNIGHT. HOWEVER...WITH THAT SAID...OUR EASTERLY GRADIENT WILL BE INCREASING AS WELL HELPING TO DRIVE THAT DRIER AIRMASS UPSTREAM TO FILTER INTO THE LOCAL AREA. WET BULB PROFILES BECOME INCREASINGLY MORE INTERESTING AS NEAR THE GROUND (SFC-950MB) WE ARE EXPECTING TEMPS TO REMAIN BELOW FREEZING OVERNIGHT INTO TUESDAY MORNING...ESPECIALLY ALONG AND NORTH OF M59. THE RUC13 HAS DONE MUCH BETTER WITH SURFACE DEWPOINTS WHICH SUGGESTS A PROLONGED PERIOD OF NEAR FREEZING TEMPS ACROSS THE TRI CITIES. QPF AMOUNTS ARE LIGHT OVERNIGHT WITH MOST OF THE QPF JUST SOUTH OF M59 (0.01-0.05") BUT AMPLE SHEAR TOP OF THE MOISTURE COLUMN OVERNIGHT COULD PROVIDE THE CHANCE FOR LIGHT PRECIP (DRIZZLE) ACROSS ALL OF SOUTHEAST LOWER. DURING TUESDAY MORNING...STILL AMPLE OPPORTUNITY FOR MORE FREEZING RAIN NORTH OF M59 WITH AGEOSTROPHIC FLOW STILL COMING FROM LOWER ONTARIO AND IMPRESSIVE MOISTURE TRANSPORT ADVECTING NORTH ALOFT. PRECIP IS EXPECTED TO EXPAND ACROSS ALL OF THE REGION QUICKLY AS SURFACE LOW DEEPENS TOWARD 990MB LATE IN THE DAY. THIS LOW BASED ON UPSTREAM PRESSURE FALLS AND PARALLEL PROFILERS UPSTREAM SHOULD TRACK NORTHWARD ACROSS THE DETROIT AND ST CLAIR RIVERS LATE IN THE DAY WHICH PROVIDES US WITH MAINLY RAIN FOR THE CWA BY NOON. THE EXCEPTION WOULD BE MIDLAND AND PERHAPS BAY COUNTY WERE WE WILL KEEP THE MIX OF RAIN/FZRA IN THE FORECAST AT THIS TIME. QPF TOTALS FOR THE DAY COULD EXCEED HALF AN INCH SO OUR CONCERN IS IF THE COLDER AIR DOES HANG ON LONGER...WE WILL NEED TO LOOK AT HEADLINES. AT THIS TIME...WE WILL STRONGLY WORD THE HWO AND OUR FORECAST AND EVENING SHIFT WILL HAVE OPPORTUNITY TO LOOK AT CURRENT TEMPS AND 00Z MODEL GUIDANCE (NOT TO MENTION PRECIP DEVELOPING UPSTREAM) BEFORE MAKING DECISIONS. AS FOR TEMPS...WITH AMPLE BREAKS UPSTREAM IN THE CLOUD FIELD AND LOWER DEWPOINTS ADVECTING INTO THE REGION...WE WILL LOWER TEMPS A GOOD 3-5 DEGREES FROM MOS. AND WITH TUESDAY WITH WET PROCESS WELL UNDERWAY...TEMPERATURES WILL HOLD TO AROUND 40 SOUTHEAST AND LOW-MID 30S NORTH AND WEST BASED ON THE LATEST SURFACE LOW FORECAST TRACK. && .LONG TERM...TUESDAY NIGHT THROUGH MONDAY THE TRANSITION FROM RAIN TO SNOW WILL BE THE FIRST PROBLEM TO DEAL WITH TUESDAY NIGHT INTO WEDNESDAY MORNING IN SE MICHIGAN. THE PACE OF TRANSITION AND POTENTIAL ACCUMULATION WILL DEPEND A LOT ON THE CHARACTER OF THE SURFACE PRESSURE PATTERN, OF WHICH THERE ARE STILL SOME CHOICES. DIFFERENCES ARE NOT HUGE IN THE OVERALL SCENARIO BUT THERE ARE PREFERENCES AMONG THE 12Z MODEL SOLUTIONS. DPROG/DT AROUND 00Z WEDNESDAY SHOWS A BIT OF A SHIFT AWAY FROM SURFACE LOW CONSOLIDATION IN THE MODELS BUT THEY HOLD ON TO A TENDENCY FOR THE UPPER TROF TO TAKE ON SOME NEGATIVE TILT. THIS UPPER AIR TENDENCY LOOKS JUSTIFIED BASED ON THE STRUCTURE OF THE UPPER JET WITH SO MUCH ENERGY ON THE DOWNSTREAM SIDE OF THE TROF AXIS. AT THE SAME TIME, THERE IS NOT ENOUGH FLOW ON THE UPSTREAM SIDE OF THE TROF TO JUSTIFY THE CLOSED CONTOURS IN THE GFS AT 500 MB. PREFER THE FULL LATITUDE LOOK OF THE NAM WITH SUPPORT FROM THE CANADIAN AND DTX WRFXX, AND EARLIER RUNS OF THE EURO MODELS. AGAIN, THE DIFFERENCES DO NOT IMPACT THE TRANSITION FROM RAIN TO SNOW AS MUCH AS QPF. THE TRANSITION IS STILL ON TRACK FOR TUESDAY EVENING FOLLOWED BY ALL SNOW OVERNIGHT INTO WEDNESDAY MORNING. THE GFS SOLUTION OFFERS HIGHER QPF WITH DEVELOPMENT OF STRONGER MID LEVEL DEFORMATION BY 12Z WEDNESDAY. WE THINK THE DEFORMATION WILL BE THERE BUT NOT AS STRONG AS THE GFS. EXPECT AN INCH OR TWO OF WET SNOW ACCUMULATION BY SUNRISE WEDNESDAY MORNING WITH CHANCE POPS LINGERING INTO THE DAYTIME. THE PROGRESSIVE NATURE OF THE LARGE SCALE PATTERN GETS THIS SYSTEM OUT OF THE GREAT LAKES BY WEDNESDAY NIGHT. HIGH PRESSURE WILL MOVE IN AND OUT QUICKLY BY THURSDAY AS YET ANOTHER WAVE MOVES INTO THE REGION, BUT THIS TIME FROM CENTRAL CANADA. INDICATIONS OF MODEST SPLIT FLOW DEVELOPMENT CONTINUE TO BE SHOWN IN THE MODELS ON THURSDAY WITH THE NORTHERN WAVE BRINGING A SURFACE LOW TO AROUND IOWA SOUTHERN MINNESOTA. WARM ADVECTION AHEAD OF THIS SYSTEM WILL KEEP A CHANCE OF RAIN AND SNOW IN THE FORECAST. THE COLD FRONT TRAILING THE THURSDAY SYSTEM WILL ENCOUNTER SOME RESISTANCE TO EASTWARD PROGRESS ON FRIDAY. THE MAJORITY OF MODEL SOLUTIONS INDICATE THAT IT WILL STALL OVER SE MICHIGAN, OR JUST TO OUR EAST, UNDER STRONG SW FLOW ALOFT. THE 00Z GFS WAS THE FARTHEST EAST SHOWING THE BOUNDARY ALONG A LINE FROM INDY TO CLEVELAND BY 00Z SATURDAY. THE 12Z RUN IS EVEN SLOWER. SINCE THESE DEVELOPMENTS LOOK PRETTY SOLID, ESPECIALLY AS THE NEXT SOUTHERN PLAINS SYSTEM GATHERS ITSELF DURING THIS TIME, WE WILL CARRY A CHANCE OF RAIN AND SNOW INTO FRIDAY BASED ON GFS THICKNESS FORECASTS. MODEL AGREEMENT IS VERY GOOD REGARDING THE TRACK OF THE SOUTHERN PLAINS SYSTEM INTO THE OHIO VALLEY ON SATURDAY, ESPECIALLY BETWEEN THE GFS AND ECMWF. THERE ARE SOME STRENGTH DIFFERENCES BUT GOOD AGREEMENT ON THE TRACK OF THE SYSTEM GENERALLY ALONG AN INDY TO CLEVELAND LINE, ALONG THE STALLED FRONT FROM FRIDAY. THE GFS IS THE STRONGEST SOLUTION IN TERMS OF THE SURFACE LOW AND WITH ALARMINGLY HIGH QPF APPROACHING 1 INCH LIQUID BY 00Z SUNDAY. THIS IS PARTIALLY DUE TO THE SYSTEM BEING WARM BUT THE TRACK IS TO OUR SOUTH, SO WE WILL CONFINE THE MENTION OF MIXED PRECIP FROM DETROIT TO THE OHIO BORDER. OVERALL, THE LARGE SCALE PATTERN FAVORS THE GFS BUT A LOT CAN CHANGE BETWEEN NOW AND THEN, WHICH SUGGESTS HOLDING OFF ON A STRONGER MENTION OF SNOW ACCUMULATION IN THE HWO FOR ANOTHER COUPLE OF FORECAST CYCLES. CONTINUED HEIGHT FALLS OVER THE NORTH PACIFIC AND GULF OF AK WILL KEEP THINGS MOVING ALONG ON SUNDAY AND MONDAY. PREFER TO KEEP THINGS DRY BOTH DAYS AS A WEAK WAVE TRACKS WELL TO OUR NORTH THROUGH CANADA ON SUNDAY. EXPECT HIGH PRESSURE TO THEN BE IN PLACE AROUND MONDAY OF NEXT WEEK. THIS PLACES MORE EMPHASIS ON THE LARGE SCALE PATTERN IN THE FORECAST WHICH SHOWS A STRONGER WAVE MOVING INTO THE ROCKIES BY THEN WITH A RIDGE OVER THE GREAT LAKES. STARTED TEMPERATURES OFF A FEW DEGREES BELOW GUIDANCE BUT STILL ABOVE NORMAL BY JANUARY STANDARDS. && .PREV DISCUSSION...ISSUED 1239 PM EST MON JAN 16 2006 AVIATION... CONDITIONS WILL BE DETERIORATING TONIGHT THROUGH THE DAY TUESDAY AS STORM SYSTEM OVER THE SOUTHERN PLAINS ORGANIZES. MAIN CONCERN FOR THESE TAFS ARE THE INCREASED POTENTIAL FOR FREEZING RAIN...MAINLY NORTH OF M59. LATEST NUMERICAL GUIDANCE SUGGESTS INITIALIZATION WAS A BIT WARMER THAN WHAT WAS OBSERVED AND WHEN UTILIZING BUFKIT AND AWIPS POINT SOUNDINGS...WE OBSERVE PLENTY OF COLD AIR NEAR THE GROUND (WET BULB PROFILES). AGEOSTROPHIC FLOW IN THE LOWER LEVELS REMAINS FROM THE EAST WITH ORIGINS FROM LOWER ONTARIO AND NORTHWESTERN PA. DEWPOINTS HERE ARE IN THE SINGLE DIGITS AND MID TEENS WITH THE POTENTIAL TO ADVECT IN THE LOWER LEVEL DEWPOINTS INTO SOUTHEAST LOWER OVERNIGHT. WHILE WARM ADVECTION ALOFT WILL BE IMPRESSIVE...EXPECT THIS COLDER AIR TO REMAIN LOCKED IN FOR A BIT LONGER HENCE THE INCREASED CHANCE FOR FREEZING RAIN EVENT FOR FNT AND MBS. BY NOON...ALL LOCATIONS SHOULD BE ALL RAIN WITH THE IMPRESSIVE WARM ADVECTION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ462-LHZ463-LHZ464 UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422 UNTIL 7 PM WEDNESDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ460 UNTIL 7 PM WEDNESDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444 UNTIL 7 PM WEDNESDAY. && $$ SHORT TERM...BGM LONG TERM....BT AVIATION...BGM 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 1050 AM EST MON JAN 16 2006 .DISCUSSION... THE MAIN CONCERN WITH THIS UPDATE IS THE POTENTIAL FOR SNOW TODAY AND TONIGHT. WATER VAPOR AND RUC/NAM SHOWINIG A LONGWAVE TROUGH OVER CENTRAL NORTH AMERICA...WITH RIDGES OVER EASTERN CONUS...AND ALONG THE PACIFIC NORTHWEST. WEAK SHORTWAVES ARE TRAVERSING THE LONGWAVE INTO THE RIDGE AND ARE OVER NORTHERN MINNESOTA...NORTHERN IOWA...AND OVER TH CENTRAL PLAINS. OTHER SHORTWAVES ARE OVER THE DAKOTAS...SOUTHERN MANITOBA AND OVER SASKATCHEWAN. THE SHORTWAVES WERE GENERATING A FEW SNOW SHOWERS ACROSS THE FORECAST AREA. SURFACE ANALYSIS DEPICT A LOW OVER SOUTHEAST IOWA WITH AN INVERTED TROUGH EXTENDING NORTH THROUGH MINNESOTA INTO SOUTHEAST MANITOBA. A WEAK FRONTAL SYSTEM STRETCHES NORTH THROUGH THIS TROUGH. A RIDGE IS TO THE EAST OF THE FORECAST AREA OVER EASTERN ONTARIO. ANOTHER RIDGE IS BULDING OVER SOUTHEAST IDAHO. SURFACE REPORTS AND KMQT-88D VAD WIND PROFILE SHOWING MOST OF SNOW EVAPORATING BEFORE HITTING THE GROUND. THIS IS OCCURRING IN AN AREA OF WEAK ISENTROPIC ASCENT AHEAD OF THE INVERTED TROUGH. THE LONGWAVE TROUGH WILL EDGE A LITTLE EAST THIS AFTERNOON. ONE SHORTWAVE ACCOMPANYING THIS LONGWAVE TROUGH WILL SWING TO THE SOUTH OF THE FORECAST AREA WHILE ANOTHER WORKS ITS WAY INTO NORTHERN WISCONSIN AND WESTERN LAKE SUPERIOR. THE IOWA LOW WILL MOVE INTO SOUTHEAST WISCONSIN DRAWING THE INVERTED TROUGH AND FRONTAL SYSTEM INTO WISCONSIN. ISENTROPIC ASCENT AHEAD OF THIS SYSTEM WILL CONTINUE TO SQUEEZE OUT A LITTLE MORE SNOW SHOWERS AND FLURRIES OVER THE AREA. WINDS OVER THE UPPE GREAT LAKES REGION WILL REMAIN OUT OF THE SOUTHEAST THROUGH THE AFTERNOON. VAD WIND PROFILE SHOWING THE PRECIPITATION LOWERING GRADUALLY. SYSTEM SEEMS TO BE RUNNING A LITTLE SLOWER THAN EARLIER MODELS SHOW...SO WILL CUT BACK POPS A BIT FOR WEST AND CENTRAL PARTS OF FORECAST AREA BUT WILL LEAVE TONIGHT ALONE UNTIL WE HAVE A CLOSER LOOK AT LATEST MODELS. I MAY TWEAK A FEW TEMPS AS WELL. && .MQT WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR MIZ002-MIZ009. SNOW ADVISORY FROM 6 PM THIS EVENING TO 4 PM EST TUESDAY FOR MIZ001-MIZ003. GALE WARNING LAKE SUPERIOR. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 500 AM EST MON JAN 16 2006 .DISCUSSION... MAIN FCST CONCERNS ARE SNOW TRENDS/AMOUNTS FROM THIS AFTERNOON INTO TUE NIGHT. WV IMAGERY...00Z RAOBS AND RUC ANALYSIS INDICATED A MID/UPR LEVEL TROF FROM THE NRN PLAINS TO THE SRN ROCKIES. THE TROF WAS FAIRLY DISORGANIZED WITH SEPARATE NRN/SRN STREAMS AND NUMEROUS SMALLER SHRTWVS/VORTS OVER THE WRN CONUS. THE NEAREST SIGNIFICANT UPSTREAM SHRTWV WAS LIFTING NE THROUGH ERN NEB. AT THE SFC...A TIGHT GRADIENT AND STRONG SE FLOW PREVAILED OVER THE WRN LAKES BTWN A RDG FROM JAMES BAY TO THE ERN LAKES AND AN INVERTED TROF TO SE MANITOBA FROM LOW PRES OVER CNTRL IA. THE MOIST SE FLOW BLO A 900 MB INVERSION HAS ALSO HELPED SUSTAIN LOW CLOUDS ACRS UPR MI. TODAY...ALTHOUGH LOW LVL MOISTURE NOT TOO THICK (NO FOG REPORTED)...CANNOT RULE OUT SOME PATCHY -FZDZ OR FLURRIES THIS MORNING OVER THE W HLF OF UPR MI AS WEAK 275K-280K ISENTROPIC LIFT CONTINUES AND MIN TEMPS IN THE MOIST LYR HOVER NEAR -8C. THE NAM/GFS SUGGEST THAT AS HGT FALLS WITH THE NRN STREAM TROF AND NEB SHRTWV ENERGY APPROACHES THE WRN LAKES...THE 290K-295K LYR ISENTROPIC LIFT WILL INCREASE WITH A BAND OF SNOW DEVELOPING INTO SW UPR MI BY LATE AFTERNOON. TONIGHT...MDLS HAVE FINALLY COME INTO BETTER AGREEMENT WITH THE MID LVL AND SFC FEATURES WITH THE INVERTED TROF AXIS FROM LK MI TO W UPR MI BY 12Z. ALTHOUGH SOME H25 WIND INITIALIZATION ERRORS OVER THE WRN CONUS WITH THE NAM/GFS WERE NOTED BY HPC THAT COULD AFFECT HOW THE PATTERN DEVELOPS...DIFFERENCES WITH THE OTHER GLOBAL MDLS WERE NOT TOO SUBSTANTIAL. MDL CONSENSUS SUGGESTS THAT LONGEST DURATION OF BEST 290K-295K LIFT/SATURATION WILL OCCUR OVER W UPR MI TONIGHT. MDL BLEND QPF IN THE 0.25-0.40 INCH RANGE WITH 12/1 SNOW/WATER RATIO WOULD SUPPORT AT LEAST 3-6 INCH SNOWFALL AMOUNTS BY 12Z/TUE. THIS IS ALSO IN LINE WITH PROGGED 3G/KG MOISTURE THAT IS AVBL. SOME LAKE ENHANCEMENT ALSO IS EXPECTED OVER THE NRN KEWEENAW WITH SE WINDS AND 900 MB TEMPS NEAR -7C. UPSLOPE FLOW INTO THE HIGHER TERRAIN COULD EASILY ALSO BRING LCL 5-6 INCH AMOUNTS. TUE...BIGGER DIFFERENCES EMERGE IN THE AMOUNT OF PCPN GENERATED AS GREATER MOISTURE SURGES TOWARD THE AREA AS THE NRN/SRN STREAMS BECOME MORE IN PHASE. THE GFS REMAINS THE MOST AGGRESSIVE IN BRINGING HIGHER QPF INTO THE ERN CWA. WHILE THIS MAY SUPPORT LCLY HEAVIER SNOW...MAINLY EAST OF P53/ISQ FAIRLY HIGH GFS ENSEMBLE QPF STD DEV/ SPREAD SUGGESTS THAT ENOUGH UNCERTAINTY REMAINS NOT TO JUMP ON ISSUING WATCH HEADLINES YET. SO...KEPT MORE CONSERVATIVE 2-4 INCH AMOUNTS IN FCST WITH POSSIBILITY THAT AMOUNTS COULD BE ADJUSTED HIGHER. WHILE LAKE ENHANCED SNOW WILL TAPER OFF AS THE TROF AXIS MOVES INTO THE KEWEENAW BY MIDDAY...EXPECT THAT COMBINATION OF SYNOPTIC AND LAKE ENHANCED AND UPSLOPE COMPONENTS MAY BRING ANOTHER 2-5 INCHES TO THE NRN KEWEENAW. TUE NIGHT...THE NAM HAS TRENDED MORE TOWARD THE GFS WITH WINDS NOT BACKING TOO FAR TO THE W BEHIND THE TROF. THIS WILL SUPPORT TRANSITION TO LIGHT TO MODERATE LAKE EFFECT SNOW OVER MOST OF NRN UPR MI BEHIND THE TROF AS H8 TEMPS DROP TO AROUND -11C. WED...PER GFS...CYCLONIC FLOW WITH H8 TEMPS DOWN TO AROUND -13C WILL SUSTAIN LIGHT TO MODERATE LES FOR LOCATIONS FAVORED BY NW FLOW. && .MQT WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR MIZ002-MIZ009. SNOW ADVISORY FROM 6 PM THIS EVENING TO 4 PM EST TUESDAY FOR MIZ001-MIZ003. GALE WARNING LAKE SUPERIOR. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 935 PM CST MON JAN 16 2006 .DISCUSSION...SENDING OUT AN UPDATE TO EXTEND THE LAKE WIND ADVISORY FOR MOST OF THE CWA DURING THE DAY TOMORROW. && .PREV DISCUSSION...FORECAST FOR THE MOST PART RUNNING AS PLANNED. FRONT IS CURRENTLY LOCATED ACROSS WSTRN AR AND ESTRN TX. ACTUALLY THIS FRONT IS MORE OF A DRY LINE AS THE COLD AIR LAGS BEHIND THE FRONT. WILL MAKE SOME ADJUSTMENTS TO TEMPS AS HOURLY TEMPS ARE LOWER THAN CURRENT TEMPS. ALSO SEE LOWS NOT QUITE REACHING AS LOW AS FORECASTED. COLD FRONT WILL PUSH THROUGH THE DELTA AROUND THE 10Z TIME FRAME AND THIS WILL HELP THE NORTHWEST COOL SOME BEFORE SUNRISE BUT I EXPECT TEMPS TO PRETTY MUCH REMAIN STEADY FOR A MAJORITY OF THE CWA THROUGH THE NIGHT WITH TEMPS ACTUALLY FALLING DURING THE DAY TOMORROW. AS FOR RAIN...LARGE SHIELD OF RAIN CONTINUES ACROSS THE NORTH WHILE TSRA ARE DEVELOPING AHEAD OF THE FRONT. LOOK FOR THESE STORMS TO BEGIN TO AFFECT THE WSTRN EDGE OF THE CWA B/T 3/4Z AND THE METRO AROUND 8Z. AS FOR STRONG/SEVERE...LOOKING AT SURROUNDING SNDGS INSTABILITY IS LACKING ALONG WITH A STRONG CAP ON LIX SNDG. THAT SAID THE RUC IS SHOWING DECENT H85 THETA E AIR PUSHING IN AHEAD OF THE FRONT ALONG WITH INCREASING DEWPOINTS AND A WEAKENING CAP. THERE IS MORE THAN ADEQUATE SHEAR IN PLACE AND WITH POSSIBLY INCREASING INSTABILITY WORKING IN FROM THE SOUTH I CAN NOT RULE OUT AN ISOLATED SEVERE STORM IN THE SOUTHEAST ALONG THAT FRONT. WILL UPDATE THE HWO TO INCLUDE THAT. ZONES AND GRIDS WILL BE OUT SHORTLY. && .AVIATION...MAIN PROBLEM TONIGHT WILL BE CEILINGS AND VISIBILITIES. BETWEEN 6 AND 8Z CEILINGS WILL DROP INTO THE MVFR RANGE(AROUND 1500 FT ) ACROSS THE NORTHWEST. THESE CEILINGS WILL WORK INTO CNTRL AND STHRN MS DURING THE MID MORNING HOURS. ALSO THERE WILL BE SOME HEAVY SHOWERS AND THUNDERSTORMS WHICH MAY DROP CEILINGS INTO IFR STATUS WITH HEIGHTS ONLY ABOUT 600 - 800 FT. I EXPECT WIDESPREAD MVFR TO EVEN IFR VISBIES WITH POSSIBLE LIFR VISBIES WITH THE HEAVIEST SHOWERS AND STRONG THUNDERSTORMS. AS THE COLD FRONT MOVES THROUGH RAIN WILL BEGIN TO TAPER OFF AND ALLOW VISBIES TO REMAIN IN THE MVFR AND VFR RANGE. CEILINGS ON THE OTHER HAND LOOK TO REMAIN AROUND 2K FT THROUGH THE DAY. AFTER THE FRONT MOVES THROUGH ANOTHER ASPECT COMES INTO PLAY...WINDS. THIS WILL HAVE LITTLE EFFECT AVIATION WISE AS WINDS WILL BE UNIDIRECTIONAL(OUT OF THE NW AND THEN W) UP TO ATLEAST 6K FT BUT WINDS DO LOOK TO BE AROUND 20KTS WITH GUSTS POSSIBLY ABV 30KTS. && .JAN WATCHES/WARNINGS/ADVISORIES... MS...LAKE WIND ADVISORY FROM 3 AM TO 6 PM CST TUESDAY FOR MSZ018- MSZ019-MSZ025-MSZ026-MSZ027-MSZ028-MSZ029-MSZ030-MSZ031- MSZ032-MSZ033-MSZ034-MSZ035-MSZ036-MSZ037-MSZ038-MSZ039- MSZ040-MSZ041-MSZ042-MSZ043-MSZ044-MSZ045-MSZ046-MSZ047- MSZ048-MSZ049-MSZ050-MSZ051-MSZ052-MSZ053-MSZ054-MSZ055- MSZ056-MSZ057-MSZ058-MSZ059-MSZ060-MSZ061-MSZ062-MSZ063. LA...LAKE WIND ADVISORY FROM 3 AM TO 6 PM CST TUESDAY FOR LAZ007- LAZ008-LAZ009-LAZ015-LAZ016-LAZ023-LAZ024-LAZ025-LAZ026. AR...LAKE WIND ADVISORY FROM 3 AM TO 6 PM CST TUESDAY FOR ARZ074- ARZ075. && $$ CAB ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 728 PM CST MON JAN 16 2006 .DISCUSSION...FORECAST FOR THE MOST PART RUNNING AS PLANNED. FRONT IS CURRENTLY LOCATED ACROSS WSTRN AR AND ESTRN TX. ACTUALLY THIS FRONT IS MORE OF A DRY LINE AS THE COLD AIR LAGS BEHIND THE FRONT. WILL MAKE SOME ADJUSTMENTS TO TEMPS AS HOURLY TEMPS ARE LOWER THAN CURRENT TEMPS. ALSO SEE LOWS NOT QUITE REACHING AS LOW AS FORECASTED. COLD FRONT WILL PUSH THROUGH THE DELTA AROUND THE 10Z TIME FRAME AND THIS WILL HELP THE NORTHWEST COOL SOME BEFORE SUNRISE BUT I EXPECT TEMPS TO PRETTY MUCH REMAIN STEADY FOR A MAJORITY OF THE CWA THROUGH THE NIGHT WITH TEMPS ACTUALLY FALLING DURING THE DAY TOMORROW. AS FOR RAIN...LARGE SHIELD OF RAIN CONTINUES ACROSS THE NORTH WHILE TSRA ARE DEVELOPING AHEAD OF THE FRONT. LOOK FOR THESE STORMS TO BEGIN TO AFFECT THE WSTRN EDGE OF THE CWA B/T 3/4Z AND THE METRO AROUND 8Z. AS FOR STRONG/SEVERE...LOOKING AT SURROUNDING SNDGS INSTABILITY IS LACKING ALONG WITH A STRONG CAP ON LIX SNDG. THAT SAID THE RUC IS SHOWING DECENT H85 THETA E AIR PUSHING IN AHEAD OF THE FRONT ALONG WITH INCREASING DEWPOINTS AND A WEAKENING CAP. THERE IS MORE THAN ADEQUATE SHEAR IN PLACE AND WITH POSSIBLY INCREASING INSTABILITY WORKING IN FROM THE SOUTH I CAN NOT RULE OUT AN ISOLATED SEVERE STORM IN THE SOUTHEAST ALONG THAT FRONT. WILL UPDATE THE HWO TO INCLUDE THAT. ZONES AND GRIDS WILL BE OUT SHORTLY. /CAB/ && .JAN WATCHES/WARNINGS/ADVISORIES... MS...LAKE WIND ADVISORY FROM 3 AM TO 6 PM CST TUESDAY FOR MSZ018- MSZ019-MSZ025-MSZ026-MSZ027-MSZ028-MSZ034-MSZ035-MSZ036- MSZ040-MSZ041-MSZ042-MSZ047-MSZ053-MSZ059-MSZ060-MSZ061. LA...LAKE WIND ADVISORY FROM 3 AM TO 6 PM CST TUESDAY FOR LAZ007- LAZ008-LAZ009-LAZ015-LAZ016-LAZ023-LAZ024-LAZ025-LAZ026. AR...LAKE WIND ADVISORY FROM 3 AM TO 6 PM CST TUESDAY FOR ARZ074- ARZ075. && $$ CAB ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX 829 PM CST MON JAN 16 2006 .UPDATE... THE COLD FRONT HAS TRANSLATED SOUTH TO ROUGHLY A BAKERSFIELD... SARAGOSA...TO PINE SPRINGS LINE. STARTING TO SEE SOME GAP WINDS THROUGH GUADAULPE PASS BUT DON'T THINK WARNING CRITERIA WILL BE MET. ELSEWHERE UPPER DYNAMICAL FORCING AND ASSOCIATED MID TROPOSPHERIC MOISTURE IS SHIFTING EAST RATHER QUICKLY WITH PASSAGE OF THE UPPER TROUGH. WE DID OBSERVE A FEW POSITIVE GROUND FLASHES EARLIER THIS EVENING COMING FROM A BAND OF ELEVATED CONVECTION ORIENTED ROUGHLY ALONG THE PECOS RIVER VALLEY. WE EXPECT THIS BAND TO TRANSLATE SOUTHEAST AND OUT ACROSS THE WESTERN EDWARDS PLATEAU WITHIN THE NEXT FEW HOURS. ANOTHER BATCH OF LIGHT PRECIP IS CURRENTLY TRANSLATING SOUTHEAST ACROSS EAST CENTRAL NEW MEXICO. DON'T THINK IT WILL AMOUNT TO MUCH OVER SOUTHEASTERN NEW MEXICO...ASSUMING IT WILL SURVIVE. WE WILL UPDATE THIS FORECAST TO TREND SIGNIFICANT WEATHER GRIDS TOWARD CURRENT AND EXPECTED SHORT TERM CONDITIONS THROUGH MIDNIGHT... HEN WILL PULL POPS ALTOGETHER AFTER 06 UTC. WE ADJUSTED THE WIND FORECAST THROUGH 12 UTC USING A BLEND OF THE 00 UTC RUC TEMPERED BY GUIDANCE. LIKEWISE WE ADJUSTED SKY GRIDS TO REFLECT EXPECTED CONDITIONS THROUGH 12 UTC. TEMPERATURES AND DEWPOINTS LOOK MORE OR LESS ON TRACK THUS NO CHANGES WERE MADE TO THESE GRIDS. DIGITAL PRODUCTS FLYING OUT THE DOOR...TEXT PRODUCTS TO FOLLOW SHORTLY. && .MAF WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 70/12 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1149 AM EST MON JAN 16 2006 .SHORT TERM UPDATE (REST OF TODAY)... FCST UPDATE SENT MAINLY TO RAISE AFTN HIGHS A FEW DEGS BASED ON CURRENT OBS AND RUC LOW LVL THICKNESS FCSTS. REGIONAL RADARS INDICATING SOME LGT RETURNS BUT DOUBT ANY PCPN CAN REACH THE GROUND GIVEN THE VERY LOW SFC DEW POINTS. ENOUGH MID/HIGH LVL CLOUDS ASSOCD WITH WEAK TROF MOVG NE THRU MTNS TO RETAIN PTSUNNY FCST THIS AFTN. ALL FLAGS DROPPED ON CSTL WTRS FOR THIS AFTN. && .PREVIOUS DISCUSSION... (ISSUED 342 AM EST MON JAN 16 2006) SHORT TERM (TODAY THROUGH TUESDAY)... SFC HI PRES HAS SETTLED OVR THE RGN DURG THE PAST 6-12 HRS...RESULTING IN LWRG WND SPDS...AND TEMPS SETTLING DN CLSR TO SEASONAL AVGS. XPCTG PDS OF MLVL CLDNS ACRS FA THRUT TDA. ISLTD "ECHOES" ON RGNL RDR...HWVR LLVLS QUITE DRY (SFC DWPTS CURRENTLY FM THE LWR TEENS TO LWR 20S...ONLY GRDLY RISING TDA)...SO NOT XPCTG ANY PCPN TO REACH GRND TDA. DUE TO PERIODIC CLDNS AND LO SUN ANGLE...TEMPS ARE LIKELY TO ONLY RISE TO NR SEASONAL AVGS MOST PLCS (LRGLY IN THE 40S). RGN WAITS FOR WRMFNT TNGT. TEMPS LIKELY TO FALL QUIKLY THIS EVE UNDER PTCHY CLDNS ERY...B4 READINGS RISE AFT MDNGT AS CLDNS ARRIVES IN ERNEST. CONTG W/ CHC POPS BY LT TNGT CNTRL/WRN SXNS OF FA...SLGT CHC ELSW. PCPN SHOULDN'T REALLY REACH AREAS OF ERN SHR (INVOF SBY)...WHR FCST LO TEMPS IN THE UPR 20S B4 RISING AFT MDNGT. TRANSITION TO WRMR CONDS DURG TUE FM S TO N AS WRMFNT PULLS N BY LT AFTN/EVE. HIEST CHC POPS INLAND AS FNT MVS N...CONTG INTO THE AFTN HRS. XPCTG DRY PD MOST PLCS BY MID/LT AFT AS LLVL FLO STARTS INCRSG FM THE S. GOING W/ HI TEMPS RNGG FM LWR/MID 50S (LT) FAR NNE SXNS OF FA...LWR/MID 60S IN THE S. LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... FA WAITS FOR STRNG CDFNT FM THE W TUE EVE...WHICH REACHES THE AREA LT TUE NGT/WED MORNING. YET ANOTHER OPPORTUNITY FOR WDSPRD RA...AND EVEN PTNTL T (THAT DESPITE NGTTM HRS - JUST LIKE PREV FNT 2 NGTS AGO). HV ADJSTD POPS TO LIKELY ALL AREAS FM AFT MDNGT TUE NGT INTO WED MORNING. DRYING W/ LLVL CAA MIDDAY/AFTN WED (COULD THERE BE CHG TO WET SNSH B4 PCPN ENDS?). CAA SHORTLIVED...AND SFC HI PRES BUILDS OVR SE CONUS FOR THU AND FRI...PRVDG A RETURN OF ABV NRML TEMPS AND DRY WX. NEXT CHC FOR PCPN NEXT WKND (CONTG IN OVRALL MILD PTRN INTO LAST WK OF JAN...THEN HOW LNG DOES IT LAST?). AVIATION...VFR THRU FCST PRD. SCT/BKN MID LVL CLDS XPCTD. MARINE...WNDS STILL AOA 25 KTS NRN WTRS WITH SEAS AOA 5 FT N OF VA / NC BRDR. THUS...WILL START OFF FCST WITH SCA N OF BRDR. ANTHR POTENT SYSTM APPRCHS BY MID WEEK. WNDS INCRS INTO SCA CRITERIA TUE NITE AHEAD OF CDFRNTL BNDRY...THEN APPRCH GALE FORCE BY WED AM. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SHORT TERM UPDATE...CULLEN va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 455 AM EST TUE JAN 17 2006 .UPDATE... WE PLACED CALLS TO MUSKEGON... KENT AND IONIA COUNTIES AND LEARNED OF SEVERAL CAR ACCIDENTS AND SLIPPERY CONDITIONS DUE TO FZRA. THEREFORE WE WILL ISSUE AN EARLY ZONE UPDATE SINCE WE WILL ISSUE A FREEZING RAIN ADVISORY FOR MUSKEGON... KENT... IONIA AND CLINTON COUNTIES UNTIL 10 AM. THE ORIGINAL FREEZING RAIN ADVISORY ISSUED FOR OUR NORTHERN CWA REMAINS UNCHANGED AND IN EFFECT THROUGH 1 PM. PREVIOUS SHORT TERM DISCUSSION... NUMEROUS SHORT TERM FCST CHALLENGES INCLUDE DETERMINING POTENTIAL FOR A FZRA EVENT OVER OUR NORTHERN CWA TODAY. WE ALSO HAVE POTENTIAL FOR A FAIRLY IMPRESSIVE SNOW EVENT TONIGHT ACROSS OUR CWA ACCOMPANIED BY INCREASING WINDS. SHORT RANGE GUIDANCE HAS COME INTO BETTER AGREEMENT AND SHOWS PCPN WILL BLOSSOM OVER OUR CWA DURING THE EARLY TO MID MORNING HOURS. MODEL FCST SOUNDINGS FOR OUR CENTRAL CWA INCLUDING GRR SUGGEST THAT AFTER A POSSIBLE BRIEF PERIOD OF -FZRA EARLY THIS MORNING PCPN WILL TRANSITION TO ALL LIQUID LATER THIS MORNING AND AFTERNOON AS SFC TEMPS MODERATE TO ABOVE FREEZING AS SFC WINDS VEER SE. I AM QUITE CONCERNED ABOUT OUR NORTHERN CWA FOR TODAY. AT THE MOMENT SFC TEMPS UP THERE ARE IN THE MID TO UPPER 20S WITH DEW PT VALUES ONLY IN THE UPPER TEENS. RUC GUIDANCE PCPN TYPE FCSTS UP THERE SUGGEST THAT FZRA COULD HANG AROUND THROUGH THE MORNING AND PERHAPS EVEN INTO THE AFTERNOON. I BELIEVE THIS SCENARIO IS LIKELY. SFC TEMPS UP THERE WILL ONLY REACH THE LOWER 30S AND ONLY EXCEED THE FREEZING MARK (BARELY) THIS AFTERNOON. IF FZRA CONTINUES BEYOND THE EARLY AFTERNOON HOURS... AN UPGRADE TO ICE STORM WARNING MAY BE NECESSARY. BOTTOM LINE... ACROSS OUR CENTRAL CWA ALONG THE I-96 CORRIDOR I BELIEVE ANY -FZRA EARLY THIS MORNING WILL BE SHORT LIVED AND TRANSITION TO PLAIN RAIN FAIRLY QUICKLY. THIS AS SFC TEMPS REACH THE MID 30S (WE NOTED THE SFC TEMP AT AZO IS ALREADY UP TO 35 AND INTO THE LOWER 40S IN NORTHERN IN). THEREFORE I DO NOT BELIEVE A HEADLINE WILL BE NECESSARY FOR OUR CENTRAL CWA FOR THIS MORNING. FOR OUR NORTHERN TWO TIERS OF COUNTIES AS WELL AS MONTCALM AND GRATIOT COUNTIES WE'LL GO WITH A FREEZING RAIN ADVISORY THRU 18Z. THE DAY SHIFT WILL NEED TO MONITOR THIS SITUATION VERY CLOSELY. IT IS CERTAINLY WITHIN THE REALM OF POSSIBILITY THAT SOME SPOTS UP THERE COULD GET AT LEAST A QUARTER OF AN INCH OF ICING SUCH THAT AN UPGRADE TO ICE STORM WARNING MAY BE NEEDED. WE OPTED FOR A FREEZING RAIN ADVISORY FOR NOW SINCE PCPN MAY (BRIEFLY) START OUT AS SNOW AND WE EXPECT SFC TEMPS TO RISE TO JUST ABOVE FREEZING MID TO LATE THIS AFTERNOON. THIS WAS COORDINATED WITH DTX/APX. FOR TONIGHT I HAVE NOTICED GUIDANCE IS TRENDING UP WITH SNOW AMOUNTS FOR OUR AREA ON THE BACK SIDE OF THE RAPIDLY INTENSIFYING LOW PRESSURE SYSTEM. THE NORTHERN AND SOUTHERN STREAM WAVES ARE ALSO COMING INTO SYNC AND OUR AREA WILL GET INTO STRONG PVA OVERNIGHT WITH POTENTIAL FOR DEFORMATION ZONE SNOWFALL TOO. AT THIS POINT GIVEN GUIDANCE TRENDS AND EXPLOSIVE CYCLOGENESIS AS WELL AS THE LOW TRACK I BELIEVE A GENERAL 2-4" SNOWFALL IS LIKELY TONIGHT FOR OUR ENTIRE CWA. GIVEN GUIDANCE TRENDS AND MY OWN INTUITION I VERY STRONGLY CONSIDERED GOING SLIGHTLY HIGHER WITH SNOW AMOUNTS AND HOISTING A SNOW OR SNOW AND BLOWING SNOW ADVISORY HEADLINE FOR TONIGHT. HOWEVER AT THIS POINT BASED ON CONFIDENCE LEVEL AND AFTER COORD WITH DTX/APX WE DECIDED TO HOLD OFF ON ANY HEADLINES FOR TONIGHT AND PLAY SNOW AMOUNTS CONSERVATIVE (FOR NOW). SNOW WILL TAPER OFF TO FLURRIES WEDNESDAY AFTERNOON AS THE LOW PRESSURE SYSTEM CONTINUES TO INTENSIFY AND LIFTS NE AWAY FROM OUR REGION. DRY WX RETURNS FOR WEDNESDAY NIGHT AND THURSDAY. THANKS FOR ALL THE COLLABORATION ON HEADLINE / FCST DECISIONS FOR TODAY AND TONIGHT APX AND DTX. .LONG TERM... UNRELENTING ZONAL FLOW CONTINUES TO REMAIN IN PLACE VIA THE MEDIUM RANGE MODELS. NO SIGNIFICANT INTRUSIONS OF ARCTIC AIR ARE EXPECTED. 850MB TEMPS WHICH COULD BE IN THE -20 TO -30 C RANGE THIS TIME OF YEAR HOVER WITHIN ABOUT 5 DEG C OF ZERO C. SO...THE WARMER THAN NORMAL TEMPS SHOULD CONTINUE. AT THIS POINT...WE HAVE NOT SEEN AN AVERAGE DAILY TEMPERATURE COME OUT BELOW NORMAL SINCE DECEMBER 21ST. A PRETTY AMAZING STRETCH FOR THE COLDEST PART OF THE YEAR IN THE GREAT LAKES. TREND IN THE MEDIUM RANGE MODELS THIS RUN IS FOR A LITTLE WARMER TEMPS. A WEAK LOW AND SURFACE TROUGH ARE FORECAST TO MOVE THROUGH THE AREA THURSDAY NIGHT. SWITCHED THE SOUTH TO ALL RAIN...AS MODEL SOUNDINGS SUPPORT THIS THEME. LEFT THE MENTION OF RAIN AND SNOW TO THE NORTH. THE LOW IS QUITE WEAK AND SHOULD NOT MUSTER MUCH IN THE WAY OF PRECIPITATION. FRIDAY SHOULD BE DRY. FOCUS THEN SHIFTS TO THE SYSTEM SWINGING OUR WAY FROM THE SOUTHERN PLAINS. THE TREND IN THE MODELS...GFS AND CANADIAN...ARE FOR A FURTHER WEST TRACK. THIS WILL YIELD MORE IN THE WAY OF RAIN AS OPPOSED TO SNOW. AT THIS POINT INTRODUCED MORE RAIN INTO THE FORECAST IN THE SOUTH WITH MIX WORDING CENTRAL AND NORTH. GIVEN THE CURRENT TRENDS WE MAY HAVE TO ADJUST THE RAIN FURTHER NORTH WITH TIME. ONE THING TO KEEP AN EYE ON HERE THOUGH IS IF WE CAN LAY DOWN A SNOWPACK ACROSS THE AREA TONIGHT. THIS COULD TREND THE LOW FURTHER SOUTH AND EAST WITH TIME CLOSER TO WHERE THE BAROCLINIC ZONE WILL PROBABLY BE. PRECIP SHOULD GO OVER TO ALL SNOW SATURDAY NIGHT IN THE WAKE OF THE SYSTEM BEFORE ENDING. 850MB TEMPS REMAIN TOO WARM FOR LAKE EFFECT EVEN IN THE WAKE OF THE SYSTEM PER THE GFS. VERY WEAK SURFACE PATTERN IN PLACE SUNDAY INTO MONDAY WITH LIGHT SOUTHWEST SURFACE FLOW. KEPT THE FORECAST DRY IN THESE PERIODS. && .GRR WATCHES/WARNINGS/ADVISORIES...FREEZING RAIN ADVISORY IN EFFECT THROUGH 1 PM FOR MASON... OCEANA... LAKE... NEWAYGO... OSCEOLA... MECOSTA... CLARE... ISABELLA... MONTCALM AND GRATIOT COUNTIES. FREEZING RAIN ADVISORY IN EFFECT FOR MUSKEGON... KENT... IONIA AND CLINTON COUNTIES THROUGH 10 AM. && $$ LAURENS DUKE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 340 AM EST TUE JAN 17 2006 .SHORT TERM... NUMEROUS SHORT TERM FCST CHALLENGES INCLUDE DETERMINING POTENTIAL FOR A FZRA EVENT OVER OUR NORTHERN CWA TODAY. WE ALSO HAVE POTENTIAL FOR A FAIRLY IMPRESSIVE SNOW EVENT TONIGHT ACROSS OUR CWA ACCOMPANIED BY INCREASING WINDS. SHORT RANGE GUIDANCE HAS COME INTO BETTER AGREEMENT AND SHOWS PCPN WILL BLOSSOM OVER OUR CWA DURING THE EARLY TO MID MORNING HOURS. MODEL FCST SOUNDINGS FOR OUR CENTRAL CWA INCLUDING GRR SUGGEST THAT AFTER A POSSIBLE BRIEF PERIOD OF -FZRA EARLY THIS MORNING PCPN WILL TRANSITION TO ALL LIQUID LATER THIS MORNING AND AFTERNOON AS SFC TEMPS MODERATE TO ABOVE FREEZING AS SFC WINDS VEER SE. I AM QUITE CONCERNED ABOUT OUR NORTHERN CWA FOR TODAY. AT THE MOMENT SFC TEMPS UP THERE ARE IN THE MID TO UPPER 20S WITH DEW PT VALUES ONLY IN THE UPPER TEENS. RUC GUIDANCE PCPN TYPE FCSTS UP THERE SUGGEST THAT FZRA COULD HANG AROUND THROUGH THE MORNING AND PERHAPS EVEN INTO THE AFTERNOON. I BELIEVE THIS SCENARIO IS LIKELY. SFC TEMPS UP THERE WILL ONLY REACH THE LOWER 30S AND ONLY EXCEED THE FREEZING MARK (BARELY) THIS AFTERNOON. IF FZRA CONTINUES BEYOND THE EARLY AFTERNOON HOURS... AN UPGRADE TO ICE STORM WARNING MAY BE NECESSARY. BOTTOM LINE... ACROSS OUR CENTRAL CWA ALONG THE I-96 CORRIDOR I BELIEVE ANY -FZRA EARLY THIS MORNING WILL BE SHORT LIVED AND TRANSITION TO PLAIN RAIN FAIRLY QUICKLY. THIS AS SFC TEMPS REACH THE MID 30S (WE NOTED THE SFC TEMP AT AZO IS ALREADY UP TO 35 AND INTO THE LOWER 40S IN NORTHERN IN). THEREFORE I DO NOT BELIEVE A HEADLINE WILL BE NECESSARY FOR OUR CENTRAL CWA FOR THIS MORNING. FOR OUR NORTHERN TWO TIERS OF COUNTIES AS WELL AS MONTCALM AND GRATIOT COUNTIES WE'LL GO WITH A FREEZING RAIN ADVISORY THRU 18Z. THE DAY SHIFT WILL NEED TO MONITOR THIS SITUATION VERY CLOSELY. IT IS CERTAINLY WITHIN THE REALM OF POSSIBILITY THAT SOME SPOTS UP THERE COULD GET AT LEAST A QUARTER OF AN INCH OF ICING SUCH THAT AN UPGRADE TO ICE STORM WARNING MAY BE NEEDED. WE OPTED FOR A FREEZING RAIN ADVISORY FOR NOW SINCE PCPN MAY (BRIEFLY) START OUT AS SNOW AND WE EXPECT SFC TEMPS TO RISE TO JUST ABOVE FREEZING MID TO LATE THIS AFTERNOON. THIS WAS COORDINATED WITH DTX/APX. FOR TONIGHT I HAVE NOTICED GUIDANCE IS TRENDING UP WITH SNOW AMOUNTS FOR OUR AREA ON THE BACK SIDE OF THE RAPIDLY INTENSIFYING LOW PRESSURE SYSTEM. THE NORTHERN AND SOUTHERN STREAM WAVES ARE ALSO COMING INTO SYNC AND OUR AREA WILL GET INTO STRONG PVA OVERNIGHT WITH POTENTIAL FOR DEFORMATION ZONE SNOWFALL TOO. AT THIS POINT GIVEN GUIDANCE TRENDS AND EXPLOSIVE CYCLOGENESIS AS WELL AS THE LOW TRACK I BELIEVE A GENERAL 2-4" SNOWFALL IS LIKELY TONIGHT FOR OUR ENTIRE CWA. GIVEN GUIDANCE TRENDS AND MY OWN INTUITION I VERY STRONGLY CONSIDERED GOING SLIGHTLY HIGHER WITH SNOW AMOUNTS AND HOISTING A SNOW OR SNOW AND BLOWING SNOW ADVISORY HEADLINE FOR TONIGHT. HOWEVER AT THIS POINT BASED ON CONFIDENCE LEVEL AND AFTER COORD WITH DTX/APX WE DECIDED TO HOLD OFF ON ANY HEADLINES FOR TONIGHT AND PLAY SNOW AMOUNTS CONSERVATIVE (FOR NOW). SNOW WILL TAPER OFF TO FLURRIES WEDNESDAY AFTERNOON AS THE LOW PRESSURE SYSTEM CONTINUES TO INTENSIFY AND LIFTS NE AWAY FROM OUR REGION. DRY WX RETURNS FOR WEDNESDAY NIGHT AND THURSDAY. THANKS FOR ALL THE COLLABORATION ON HEADLINE / FCST DECISIONS FOR TODAY AND TONIGHT APX AND DTX. .LONG TERM... UNRELENTING ZONAL FLOW CONTINUES TO REMAIN IN PLACE VIA THE MEDIUM RANGE MODELS. NO SIGNIFICANT INTRUSIONS OF ARCTIC AIR ARE EXPECTED. 850MB TEMPS WHICH COULD BE IN THE -20 TO -30 C RANGE THIS TIME OF YEAR HOVER WITHIN ABOUT 5 DEG C OF ZERO C. SO...THE WARMER THAN NORMAL TEMPS SHOULD CONTINUE. AT THIS POINT...WE HAVE NOT SEEN AN AVERAGE DAILY TEMPERATURE COME OUT BELOW NORMAL SINCE DECEMBER 21ST. A PRETTY AMAZING STRETCH FOR THE COLDEST PART OF THE YEAR IN THE GREAT LAKES. TREND IN THE MEDIUM RANGE MODELS THIS RUN IS FOR A LITTLE WARMER TEMPS. A WEAK LOW AND SURFACE TROUGH ARE FORECAST TO MOVE THROUGH THE AREA THURSDAY NIGHT. SWITCHED THE SOUTH TO ALL RAIN...AS MODEL SOUNDINGS SUPPORT THIS THEME. LEFT THE MENTION OF RAIN AND SNOW TO THE NORTH. THE LOW IS QUITE WEAK AND SHOULD NOT MUSTER MUCH IN THE WAY OF PRECIPITATION. FRIDAY SHOULD BE DRY. FOCUS THEN SHIFTS TO THE SYSTEM SWINGING OUR WAY FROM THE SOUTHERN PLAINS. THE TREND IN THE MODELS...GFS AND CANADIAN...ARE FOR A FURTHER WEST TRACK. THIS WILL YIELD MORE IN THE WAY OF RAIN AS OPPOSED TO SNOW. AT THIS POINT INTRODUCED MORE RAIN INTO THE FORECAST IN THE SOUTH WITH MIX WORDING CENTRAL AND NORTH. GIVEN THE CURRENT TRENDS WE MAY HAVE TO ADJUST THE RAIN FURTHER NORTH WITH TIME. ONE THING TO KEEP AN EYE ON HERE THOUGH IS IF WE CAN LAY DOWN A SNOWPACK ACROSS THE AREA TONIGHT. THIS COULD TREND THE LOW FURTHER SOUTH AND EAST WITH TIME CLOSER TO WHERE THE BAROCLINIC ZONE WILL PROBABLY BE. PRECIP SHOULD GO OVER TO ALL SNOW SATURDAY NIGHT IN THE WAKE OF THE SYSTEM BEFORE ENDING. 850MB TEMPS REMAIN TOO WARM FOR LAKE EFFECT EVEN IN THE WAKE OF THE SYSTEM PER THE GFS. VERY WEAK SURFACE PATTERN IN PLACE SUNDAY INTO MONDAY WITH LIGHT SOUTHWEST SURFACE FLOW. KEPT THE FORECAST DRY IN THESE PERIODS. && .GRR WATCHES/WARNINGS/ADVISORIES...FREEZING RAIN ADVISORY IN EFFECT THROUGH 1 PM FOR MASON... OCEANA... LAKE... NEWAYGO... OSCEOLA... MECOSTA... CLARE... ISABELLA... MONTCALM AND GRATIOT COUNTIES. && $$ LAURENS DUKE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1142 PM EST MON JAN 16 2006 .AVIATION... VIRTUALLY NO CHANGES TO TAFS THROUGH DAYTIME OF TUESDAY...AS 00Z MODEL RUNS CLOSELY APPROXIMATE EARLIER THINKING... LATEST MODELS PORTRAY RIDGE EAST OF AREA SLOWLY RETREATING EAST. DRY EASTERLY FLOW CONTINUES TO COMBAT MOISTENING TREND FROM THE EVOLVING LOW JUST TO THE SOUTHWEST...AND THIS IS LIKELY TO BE THE CASE OVERNIGHT AND INTO TUESDAY...WITH SURFACE DEW POINTS/WET BULB TEMPERATURES THUS SLOW TO RISE...AND HELPING SUPPORT CHANCES FOR FREEZING DRIZZLE/FREEZING RAIN...THOUGH AMOUNTS EXPECTED LIGHT...AFTER 11Z. LATEST MODEL CONSENSUS CONTINUES TO INDICATE THAT THE PRECIPITATION WILL LARGELY OCCUR AFTER IT WARMS ENOUGH FOR PROBABLE NON FREEZING PRECIPITATION TYPE...BUT THERE IS STILL POSSIBILITY FOR SEVERAL HOURS OF ONSET LIGHTER FREEZING VARIETY... WHICH CONDITIONS ARE INCORPORATED INTO TAFS FOR TUESDAY MORNING. LOWERED CEILINGS OVERNIGHT INTO MVFR CATEGORY AS THIS LOOKS ON TARGET IN LIGHT OF CURRENT SURFACE OBSERVATION TRENDS. THEN...STEADILY DOWNHILL CONDITIONS TUESDAY FORENOON INTO IFR...BOTH RESPECT TO CEILINGS AND VISIBILITIES...CONTINUING IFR AND RAINY ON THROUGH THE AFTERNOON. FOR ALL TAFS...HAVE ALSO INCLUDED A LOW LEVEL WIND SHEAR GROUP TUESDAY MORNING THROUGH MID DAY...WITH STRONGLY VEERING WINDS AND SPEED SHEAR AS WELL. USING MAINLY NAM MODEL SOUNDINGS...HAVE CHANGED PRECIPITATION OVER TO SNOW LATE TUESDAY EVENING. && .UPDATE...ISSUED 944 PM EST MON FORECASTS UPDATED TO SLOW DOWN ARRIVAL OF PRECIPITATION TO TOWARD DAYBREAK. 18Z NAM AND ALSO RUC SEEMED TO BE HANDLING QPF EXTENT SOUTHWEST OF AREA BEST THIS EVENING...AS WELL AS IN HANDLING OF DRY AIR FEEDING IN FROM THE EAST IN TERMS OF SLOWER WARMING OF SURFACE DEW POINTS/WET BULB TEMPERATURES. ALSO...THESE MODELS PORTRAYED ONLY A VERY FEW HUNDREDTHS OF AN INCH QPF AT MOST BY 15Z...AND EVEN LESS THAN A TENTH OF INCH IN THE FAR NORTH THROUGH 18Z WHERE ABOVE FREEZING TEMPERATURES WILL BE MOST DELAYED. THE 00Z DTX SOUNDING WAS A GOOD FIT TO THE 18Z NAM FORECAST SOUNDING...TOO. QUICK EARLIEST PEEKS AT 00Z NAM/RUC SHOW SIMILAR IDEAS. THUS...NOT INCLINED FOR ANY HEADLINES FOR FREEZING PRECIPITATION AT THIS JUNCTURE...BUT WILL WATCH THE EVOLVING OF THE WEATHER OVERNIGHT FOR POSSIBLE HEADLINES BY RUSH HOUR...IF NEEDED. && .SHORT TERM...TONIGHT AND TUESDAY...ISSUED 343 PM EST MON AN INTERESTING AND EQUALLY CHALLENGING FORECAST TONIGHT INTO TUESDAY MORNING. WATER VAPOR LOOP REVEALS TROUGH HAS JUST MOVED OUT INTO THE WESTERN HIGH PLAINS WITH THE BASE OF THIS TROUGH ROUNDING OUT THROUGH NEW MEXICO THIS AFTERNOON. UPSTREAM WIND PROFILER NETWORK SHOWS A 130-140KT 300MB JET INTERACTING WITH SUBTROPICAL MOISTURE FROM THE PACIFIC THAT IS CURRENTLY RESULTING IN PRECIP DEVELOPMENT ACROSS ARKLATEX REGION WITH RADAR RETURNS ACROSS MISSOURI NOT REACHING THE GROUND (VIRGA). SURFACE WARM FRONT WAS ANALYZED ACROSS CENTRAL IL/IN/OH FROM MAIN SURFACE LOW NEAR PITTSFIELD ILLINOIS. TO OUR NORTHEAST WAS A LARGE SURFACE HIGH OF 1025MB OVER JAMES BAY WHERE DEWPOINTS ACROSS LOWER ONTARIO WERE IN THE SINGLE DIGITS AND MID TEENS. SO THE POTENTIAL FOR A WINTRY MESS IS SETTING UP ACROSS SOUTHEAST LOWER MICHIGAN LATE TONIGHT INTO TUESDAY MORNING IN THE FORM OF FREEZING RAIN. 12Z NUMERICAL SUITE INITIALIZED A COUPLE OF DEGREES TOO WARM AND A QUICK LOOK AT THE 18Z NAM SUGGESTS THIS WITH NEAR SURFACE WET BULB AND DEWPOINT TEMPS DROPPING ANOTHER DEGREE IN THE NUMERICAL RUN. AS SYSTEM DEEPENS UPSTREAM...AGEOSTROPHIC FLOW INCREASES AS WELL WHICH POINTS FROM NORTHWEST PA (STREAMLINE ANALYSIS) AND ACROSS LOWER ONTARIO. THIS POINTS TOWARD LOWER SURFACE DEWPOINTS/DRIER AIR FILTERING INTO SOUTHEAST LOWER AS ABUNDANT MOISTURE TRANSPORT DEVELOPS ALOFT EMBEDDED WITHIN THE LOW LEVEL JET AXIS. WITH AMPLE BREAKS IN THE MID AND HIGH LEVEL CLOUDINESS SEEN IN THE 1 KM VISIBLE IMAGERY AND OUR ALREADY LOW DEWPOINTS...WE COULD SEE A BRIEF PERIOD OF THIS EVENING OF DECENT COOLING BEFORE THE THICKER CLOUDS ARRIVE OVERNIGHT. HOWEVER...WITH THAT SAID...OUR EASTERLY GRADIENT WILL BE INCREASING AS WELL HELPING TO DRIVE THAT DRIER AIRMASS UPSTREAM TO FILTER INTO THE LOCAL AREA. WET BULB PROFILES BECOME INCREASINGLY MORE INTERESTING AS NEAR THE GROUND (SFC-950MB) WE ARE EXPECTING TEMPS TO REMAIN BELOW FREEZING OVERNIGHT INTO TUESDAY MORNING...ESPECIALLY ALONG AND NORTH OF M59. THE RUC13 HAS DONE MUCH BETTER WITH SURFACE DEWPOINTS WHICH SUGGESTS A PROLONGED PERIOD OF NEAR FREEZING TEMPS ACROSS THE TRI CITIES. QPF AMOUNTS ARE LIGHT OVERNIGHT WITH MOST OF THE QPF JUST SOUTH OF M59 (0.01-0.05") BUT AMPLE SHEAR TOP OF THE MOISTURE COLUMN OVERNIGHT COULD PROVIDE THE CHANCE FOR LIGHT PRECIP (DRIZZLE) ACROSS ALL OF SOUTHEAST LOWER. DURING TUESDAY MORNING...STILL AMPLE OPPORTUNITY FOR MORE FREEZING RAIN NORTH OF M59 WITH AGEOSTROPHIC FLOW STILL COMING FROM LOWER ONTARIO AND IMPRESSIVE MOISTURE TRANSPORT ADVECTING NORTH ALOFT. PRECIP IS EXPECTED TO EXPAND ACROSS ALL OF THE REGION QUICKLY AS SURFACE LOW DEEPENS TOWARD 990MB LATE IN THE DAY. THIS LOW BASED ON UPSTREAM PRESSURE FALLS AND PARALLEL PROFILERS UPSTREAM SHOULD TRACK NORTHWARD ACROSS THE DETROIT AND ST CLAIR RIVERS LATE IN THE DAY WHICH PROVIDES US WITH MAINLY RAIN FOR THE CWA BY NOON. THE EXCEPTION WOULD BE MIDLAND AND PERHAPS BAY COUNTY WERE WE WILL KEEP THE MIX OF RAIN/FZRA IN THE FORECAST AT THIS TIME. QPF TOTALS FOR THE DAY COULD EXCEED HALF AN INCH SO OUR CONCERN IS IF THE COLDER AIR DOES HANG ON LONGER...WE WILL NEED TO LOOK AT HEADLINES. AT THIS TIME...WE WILL STRONGLY WORD THE HWO AND OUR FORECAST AND EVENING SHIFT WILL HAVE OPPORTUNITY TO LOOK AT CURRENT TEMPS AND 00Z MODEL GUIDANCE (NOT TO MENTION PRECIP DEVELOPING UPSTREAM) BEFORE MAKING DECISIONS. AS FOR TEMPS...WITH AMPLE BREAKS UPSTREAM IN THE CLOUD FIELD AND LOWER DEWPOINTS ADVECTING INTO THE REGION...WE WILL LOWER TEMPS A GOOD 3-5 DEGREES FROM MOS. AND WITH TUESDAY WITH WET PROCESS WELL UNDERWAY...TEMPERATURES WILL HOLD TO AROUND 40 SOUTHEAST AND LOW-MID 30S NORTH AND WEST BASED ON THE LATEST SURFACE LOW FORECAST TRACK. && .LONG TERM...TUESDAY NIGHT THROUGH MONDAY...ISSUED 343 PM EST MON THE TRANSITION FROM RAIN TO SNOW WILL BE THE FIRST PROBLEM TO DEAL WITH TUESDAY NIGHT INTO WEDNESDAY MORNING IN SE MICHIGAN. THE PACE OF TRANSITION AND POTENTIAL ACCUMULATION WILL DEPEND A LOT ON THE CHARACTER OF THE SURFACE PRESSURE PATTERN, OF WHICH THERE ARE STILL SOME CHOICES. DIFFERENCES ARE NOT HUGE IN THE OVERALL SCENARIO BUT THERE ARE PREFERENCES AMONG THE 12Z MODEL SOLUTIONS. DPROG/DT AROUND 00Z WEDNESDAY SHOWS A BIT OF A SHIFT AWAY FROM SURFACE LOW CONSOLIDATION IN THE MODELS BUT THEY HOLD ON TO A TENDENCY FOR THE UPPER TROF TO TAKE ON SOME NEGATIVE TILT. THIS UPPER AIR TENDENCY LOOKS JUSTIFIED BASED ON THE STRUCTURE OF THE UPPER JET WITH SO MUCH ENERGY ON THE DOWNSTREAM SIDE OF THE TROF AXIS. AT THE SAME TIME, THERE IS NOT ENOUGH FLOW ON THE UPSTREAM SIDE OF THE TROF TO JUSTIFY THE CLOSED CONTOURS IN THE GFS AT 500 MB. PREFER THE FULL LATITUDE LOOK OF THE NAM WITH SUPPORT FROM THE CANADIAN AND DTX WRFXX, AND EARLIER RUNS OF THE EURO MODELS. AGAIN, THE DIFFERENCES DO NOT IMPACT THE TRANSITION FROM RAIN TO SNOW AS MUCH AS QPF. THE TRANSITION IS STILL ON TRACK FOR TUESDAY EVENING FOLLOWED BY ALL SNOW OVERNIGHT INTO WEDNESDAY MORNING. THE GFS SOLUTION OFFERS HIGHER QPF WITH DEVELOPMENT OF STRONGER MID LEVEL DEFORMATION BY 12Z WEDNESDAY. WE THINK THE DEFORMATION WILL BE THERE BUT NOT AS STRONG AS THE GFS. EXPECT AN INCH OR TWO OF WET SNOW ACCUMULATION BY SUNRISE WEDNESDAY MORNING WITH CHANCE POPS LINGERING INTO THE DAYTIME. THE PROGRESSIVE NATURE OF THE LARGE SCALE PATTERN GETS THIS SYSTEM OUT OF THE GREAT LAKES BY WEDNESDAY NIGHT. HIGH PRESSURE WILL MOVE IN AND OUT QUICKLY BY THURSDAY AS YET ANOTHER WAVE MOVES INTO THE REGION, BUT THIS TIME FROM CENTRAL CANADA. INDICATIONS OF MODEST SPLIT FLOW DEVELOPMENT CONTINUE TO BE SHOWN IN THE MODELS ON THURSDAY WITH THE NORTHERN WAVE BRINGING A SURFACE LOW TO AROUND IOWA SOUTHERN MINNESOTA. WARM ADVECTION AHEAD OF THIS SYSTEM WILL KEEP A CHANCE OF RAIN AND SNOW IN THE FORECAST. THE COLD FRONT TRAILING THE THURSDAY SYSTEM WILL ENCOUNTER SOME RESISTANCE TO EASTWARD PROGRESS ON FRIDAY. THE MAJORITY OF MODEL SOLUTIONS INDICATE THAT IT WILL STALL OVER SE MICHIGAN, OR JUST TO OUR EAST, UNDER STRONG SW FLOW ALOFT. THE 00Z GFS WAS THE FARTHEST EAST SHOWING THE BOUNDARY ALONG A LINE FROM INDY TO CLEVELAND BY 00Z SATURDAY. THE 12Z RUN IS EVEN SLOWER. SINCE THESE DEVELOPMENTS LOOK PRETTY SOLID, ESPECIALLY AS THE NEXT SOUTHERN PLAINS SYSTEM GATHERS ITSELF DURING THIS TIME, WE WILL CARRY A CHANCE OF RAIN AND SNOW INTO FRIDAY BASED ON GFS THICKNESS FORECASTS. MODEL AGREEMENT IS VERY GOOD REGARDING THE TRACK OF THE SOUTHERN PLAINS SYSTEM INTO THE OHIO VALLEY ON SATURDAY, ESPECIALLY BETWEEN THE GFS AND ECMWF. THERE ARE SOME STRENGTH DIFFERENCES BUT GOOD AGREEMENT ON THE TRACK OF THE SYSTEM GENERALLY ALONG AN INDY TO CLEVELAND LINE, ALONG THE STALLED FRONT FROM FRIDAY. THE GFS IS THE STRONGEST SOLUTION IN TERMS OF THE SURFACE LOW AND WITH ALARMINGLY HIGH QPF APPROACHING 1 INCH LIQUID BY 00Z SUNDAY. THIS IS PARTIALLY DUE TO THE SYSTEM BEING WARM BUT THE TRACK IS TO OUR SOUTH, SO WE WILL CONFINE THE MENTION OF MIXED PRECIP FROM DETROIT TO THE OHIO BORDER. OVERALL, THE LARGE SCALE PATTERN FAVORS THE GFS BUT A LOT CAN CHANGE BETWEEN NOW AND THEN, WHICH SUGGESTS HOLDING OFF ON A STRONGER MENTION OF SNOW ACCUMULATION IN THE HWO FOR ANOTHER COUPLE OF FORECAST CYCLES. CONTINUED HEIGHT FALLS OVER THE NORTH PACIFIC AND GULF OF AK WILL KEEP THINGS MOVING ALONG ON SUNDAY AND MONDAY. PREFER TO KEEP THINGS DRY BOTH DAYS AS A WEAK WAVE TRACKS WELL TO OUR NORTH THROUGH CANADA ON SUNDAY. EXPECT HIGH PRESSURE TO THEN BE IN PLACE AROUND MONDAY OF NEXT WEEK. THIS PLACES MORE EMPHASIS ON THE LARGE SCALE PATTERN IN THE FORECAST WHICH SHOWS A STRONGER WAVE MOVING INTO THE ROCKIES BY THEN WITH A RIDGE OVER THE GREAT LAKES. STARTED TEMPERATURES OFF A FEW DEGREES BELOW GUIDANCE BUT STILL ABOVE NORMAL BY JANUARY STANDARDS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ462-LHZ463-LHZ464...UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY...LHZ421 AND NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 7 PM WEDNESDAY. SMALL CRAFT ADVISORY FOR WINDS...LHZ422...UNTIL 7 PM WEDNESDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ460...UNTIL 7 PM WEDNESDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444...UNTIL 7 PM WEDNESDAY. && $$ AVIATION...DWD SHORT TERM...BGM LONG TERM....BT 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 LOUISVILLE KY 1047 AM EST TUE JAN 17 2006 .MORNING UPDATE... CURRENTLY...A COLD FRONT OVER THE FAR WRN CWA IS PASSING THROUGH THE REGION. THE FRONT IS VERY EASY TO PICK OUT BASED ON SFC OBS...WHERE HUNTINGBURG INDIANA IS ALREADY DOWN TO 37 DEGREES AND HAS NW WINDS GUSTING TO AROUND 30 MPH. AHEAD OF THE FRONT...LOUISVILLE AND FT. KNOX AND OTHER SUCH LOCATIONS ARE REPORTING MID 50S AND SOUTHERLY WINDS. QUITE A CHANGE WITH THIS FRONT! IN ADDITION...THE BACK EDGE OF THE MODERATE RAINFALL IS PRETTY MUCH ALIGNED WITH INTERSTATE 65...WHERE ONLY LIGHT SHOWERS RESIDE BEHIND THE FRONT. ALTHOUGH THERE IS A SHARP GRADIENT WHERE THE RAINFALL ENDS...TWO STRONG VORT MAXES EMBEDDED WITHIN APPROACHING TROUGH COULD HELP TRIGGER ADDITIONAL SCATTERED RAIN SHOWERS BEHIND THE FRONT. RUC ANALYZED 850MB DEWPOINT GRADIENT STILL ACROSS WRN KY...SO THINK SHOWERS WILL STILL BE POSSIBLE. HAVE DECREASED POPS FROM 100 OVER WRN CWA DOWN TO AROUND 30 POPS WITH RAIN WORDING. ALSO HAVE RAIN SWITCHING OVER TO SNOW FROM WEST TO EAST FROM ROUGHLY 22Z TO 04Z. WILL ALSO MENTION GUSTY WINDS BEHIND THE FROPA FOR THIS AFTERNOON. UPDATE OUT SHORTLY. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ AL ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 930 AM CST TUE JAN 17 2006 FORECAST CHALLENGE CONCERNS CLOUD TRENDS AND TEMPERATURES. CLEAR SLOT OVER NORTH CENTRAL MN SHIFTING EAST AND PRETTY MUCH EAST OF FA. BACK EDGE OF CLOUD SHIELD ALONG A KISN-KBIS LINE AND MOVING LITTLE IN PAST FEW HOURS. A FEW BREAKS SHOWING UP IN S MB HOWEVER WITH LOW CONVECTIVE TEMPERATURES AND LOW LEVEL MOIST LAYER PERSISTING MOST OF DAY VIA RUC DO NOT FEEL ANY SOLAR WILL BE A FACTOR. WITH CLOUDS HOLDING AND COLD POOL AXIS OVER FA TEMPERATURES WILL HOLD PRETTY MUCH WITH EXCEPTION OF FAR NE WHERE CLOUDS MOVING BACK IN SHOULD ALLOW FOR MODEST RECOVERY INTO TEENS. WILL ALSO MAINTAIN FLURRIES WHICH ARE CURRENTLY FAIRLY WIDESPREAD. OVERALL MINIMAL CHANGES PLANNED TO UPDATE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1107 AM EST TUE JAN 17 2006 .SHORT TERM (REST OF TODAY)... EXPECTING A MILD AND MNLY DRY AFTN AS WSW-ENE ORIENTED WARM FRONT CURRENTLY NEAR A RZZ-ORF LINE CONTS TO LIFT NORTH. LTST RUC SUGGS STRENGHTENING/DEEPENING SOUTHERN FLOW WILL ALLOW EROSION OF LOW LVL WEDGE ALL INLAND AREAS THIS AFTN (ALTHOUGH MAY TAKE UNTIL ALMOST SUNSET IN FAR NW FLUVANNA/LOUISA COUNTIES). SHUD SEE INCRSG SUNSHINE THIS AFTN ESP EASTERN AREAS AS LOW CLOUDS MIX OUT. SO MAIN REASON FOR LATE MORN FCST UPDATE WAS TO RAISE AFTN HIGHS ABOUT A CAT MOST AREAS AND RAISED EVEN HIGHER OVR INLAND SE AREAS (NE NC/SE VA) WHERE NEAR 70 DEGS PSBL. REGIONAL RADARS TO SOUTH VOID OF ANY PCPN AND SEE LTL REASON FOR INCRSG POPS THIS AFTN WITH BAND OF ISENTROPIC UPGLIDE LIFTING NORTH OF AREA WITH WARM FRONT. WILL HANG ONTO LOW/SLIGHT CHCS AFTN PCPN FAR NW AREAS WHICH WL RMN WEDGED LONGER. && .PREVIOUS DISCUSSION... (ISSUED 318 AM EST TUE JAN 17 2006) TODAY...FOLLOWED A GFS SOLN AS IT APPEARS TO HAVE A BETTER HANDLE ON CRNT PCPN. WRM FRNT / ASSCTD ADVCTN PCPN MOVG NE THRU NC & SHUD CONT TO TRACK NE ACROSS FA THIS AM. QSTN AS TO HOW FAR N WRM FRNT ACTUALLY GETS TDY. THUS..WILL KEEP CHC POPS (AND LOWEST TMPS) XTREME NW CNTYS. SERN SCTNS MAY ACTUALLY SEE SOME PRTL SUNSHINE THIS AFTRN. THIS WUD ALLOW TMPS TO JUMP BTWN 60-65. TONIGHT...APPRCHG SYSTM TAKES ON A NEG TILT MUCH LIKE LAST SYSTM... THOUGH IT DOES HAVE IT DIFFERENCES. PRIME OF WHICH IS THE TRACK OF UPR LVL LOW. THIS ONE IS PROGGED TO TRACK NW OF FA WHILE LAST ONE TRACKED RIGHT OVR FA. COMBO OF INCRG THETAE ADVCTN THIS EVE AND A STRNG (50-60KT) LL JET...WILL INCRS POPS TO CAT ALL AREAS & CONT CHC THUNDER MAINLY AFTR MIDNITE. ONLY THING LACKING FOR ANTHR ROUND OF WDSPRD SVR CONVECTION IS THE INSTABILITY. XPCT INCRG SRLY WNDS WITH TMPS RISING (55-60) THIS EVE...THEN FALLING ACROSS WRN CNTYS AFTR FROPA. THREAT WILL BE FOR DMMNG WNDS IN ANY CONVECTION. WEDNESDAY...CDFRNT MOVES OFFSHORE BY 18Z...TAKING PCPN WITH IT. TSCTNS SUGGEST AIRMASS DRYS OUT RTHR QUICKLY RESULTING IN A PT TO MSTLY SUNNY AFTRN W OF CHES BAY. CAA CONTS ON GUSTY W-NW WNDS. TMPS U40S-M50S. THURSDAY / FRIDAY...ANTHR WRMG TREND AS H5 HGHTS & H85 TMPS RISE. TMPS BY FRI 65 TO PSBLY 70. SATURDAY THROUGH MONDAY...NXT FRNT APPRCHS SAT WITH CHC SHWRS. TMPS WELL INTO 60S. DRY BUT COOLER (50S) SUN INTO MON. AVIATION...MVFR IN CIGS/LGT R THROUGH MIDDAY/ERY AFTN HRS. PD OF VFR MID/LT AFTN THROUGH EVE HRS. MARINE...RELATIVELY LGT ESE WNDS THIS MORNING...INCRSG FM THE SE TO GENLY 10 TO 15 KT...W/ WVS/SEAS BUILDING A FOOT OR TWO ON AVG. 925 MB 50-60 KT S JET MAX CRSS RGN TNGT...GOING W/ ABT 60% OF THAT DUE TO WAA OVR "COLDER" WTRS. HV DECIDED TO HOIST GALES ALL AREAS FOR PTNTL 35-45 KT FM AFT 02-04Z TNGT INTO ERY MORNING (BAY/SND)... THRUT DAY WED OCN. WNDS SHIFT FM S DRCTN TNGT...TO WSW FOR WED ALL AREAS AFT CDFNTL PASSAGE. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...GALE WARNING FOR NCZ102 FROM 9 PM TUESDAY TO 8 PM WEDNESDAY. VA...NONE. MARINE...GALE WARNING FOR ANZ630-631 FROM 9 PM TUESDAY TO 6 AM WEDNESDAY. ...GALE WARNING FOR ANZ632-633 FROM 9 PM TUESDAY TO 8 AM WEDNESDAY. ...GALE WARNING FOR ANZ650-652-654 FROM 9 PM TUESDAY TO 10 PM WEDNESDAY. ...GALE WARNING FOR ANZ656-658 FROM 9 PM TUESDAY TO 8 PM WEDNESDAY. && $$ SHORT TERM UPDATE...CULLEN va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 1014 AM EST TUE JAN 17 2006 .SHORT TERM (REST OF TODAY)... ANALYSIS SHOWING WARM FRONT DANGLING ACROSS THE FAR SOUTHERN/SW PORTION OF THE CWA THIS MORNING WITH RAINFALL INDUCED WEDGE IN PLACE. MAIN AXIS OF RAINFALL WITH THIS FEATURE NOW PUSHING NORTH OF HIGHWAY 460 ASSOCIATED WITH INITIAL SLUG OF ISENTROPIC LIFT. MAIN QUESTIONS THIS AFTERNOON WITH EASTWARD EXTENT OF SHRA AHEAD OF THE COLD FRONT NOW APPROACHING THE TN VALLEY AND HOW STRONG WEDGE WILL BE AS WAA ALOFT ATTEMPTS TO MIX DOWN. LATEST RUC/WRF SUGGEST THAT THE MAJORITY OF THE LIFT WILL STAY TO THE WEST/NORTH THIS AFTERNOON ONCE THIS BATCH OF -RA EXITS AND FRONTAL SHRA GETS DELAYED AS NEXT S/W RIDES UP THE BOUNDARY. LESS PRECIP SHOULD ALSO ACT TO HELP WEDGE SLOWLY ERODE FROM SOUTH TO NORTH BUT WILL BE A SLOW PROCESS WITH LOCATIONS IN THE SHENANDOAH VALLEY LIKELY STAYING IN THE COLD POOL. WINDS ALSO AN ISSUE WHERE WARM AIR HAS SCOURED OUT THE WEDGE IN THE FAR WEST ALTHO THINK INCREASING TO JUST BELOW ADVISORY LEVELS WILL WORK FOR NOW GIVEN LIGHT PRECIP IN THE AREA. OTHERWISE WILL CONTINUE THE TREND OF ONLY CHANCE POPS ALL EXCEPT FAR NW EARLY ON...THEN INCREASING OVER THE WEST BY MID/LATE AFTERNOON AHEAD OF THE FRONT. MAY REMOVE TSRA MENTION FAR W GIVEN LACK OF INSTAB AND TREND OF MORE LOW TOPPED CONVECTION TO THE WEST. HIGH TEMPS LIKELY MORE OF A LATE AFTERNOON SCENARIO AS WARM AIR ALOFT DEEPENS AND MIXING INCREASES. MAY LOWER HIGHS SOME IN THE WEDGE REGIONS OTHERWISE ONLY SOME SLIGHT CHANGES. && .PREVIOUS DISCUSSION... (ISSUED 650 AM EST TUE JAN 17 2006) AVIATION... OVERRUNNING RAIN WILL BE AFFECTING ALL OF THE TAF SITES THIS MORNING- HEAVIEST AT BLF AND LWB. CIGS ARE EXPECTED TO COME DOWN TO MVFR OR IFR...VSBYS TO MVFR. ALL TAF SITES WILL LIKELY STAY DOWN AT LEAST TO MVFR...BUT DAN AND BLF MAY REACH VFR CIGS THIS AFTERNOON. MAIN CONCERN BEFORE THE PRECIPITATION MOVES IN AHEAD OF THE STRONG COLD FRONT WILL BE FOR LLWS. THINK THAT SURFACE WINDS WILL STAY FAIRLY LOW- PARTICULARLY IN A COLD AIR WEDGE THAT HAS DEVELOPED FROM THE LIGHT RAIN. WINDS JUST A FEW THOUSAND FEET ABOVE THE SURFACE WILL INCREASE TO 35 OR 40 KNOTS THIS AFTERNOON AND INTO THIS EVENING. TIMED THE FRONT THROUGH OVERNIGHT WITH WINDS SHIFTING FROM THE SOUTHEAST AND SOUTH TO THE WEST. STRONG WINDS IN THE COLD ADVECTION BEHIND THE FRONT LOOK TO HOLD OFF TILL AFTER 12Z. PREVIOUS DISCUSSION... (ISSUED 341 AM EST TUE JAN 17 2006) SHORT TERM (TODAY THROUGH TONIGHT)... FIRST ORDER OF BUSINESS IS THE OVERRUNNING RAIN SPREADING NEWD ACROSS THE CWA AHEAD OF A WARM FRONT. BEST ISENTROPIC LIFT REMAINS TO THE WEST TODAY...BUT IT APPEARS THAT SOME LIGHT RAIN MAY EVEN AFFECT THE VA PIEDMONT THIS MORNING. I HAVE RAISED THE POPS TO INCLUDE A PERIOD OF AT LEAST LIKELY POPS EVERYWHERE THIS MORNING. SHOULD NOT BE MUCH PRECIP IN THE EAST...GENERALLY A TENTH OF AN INCH OR LESS...BUT I THINK IT WILL MEASURE. MODELS NOW SHOWING THE THE RAIN LASTING INTO AFTERNOON IN THE VA HIHGLANDS AND GREENBRIER AREA...SO I EXTENDED THE HIGHER POPS INTO THE AFTERNOON. OTHER BIG CHANGE TO THE FORECAST IS TO LOWER TEMPS EAST OF THE MTNS ESPECIALLY IN THE VA PIEDMONT AND IN VA HIGHLANDS AND GREENBRIER VALLEY WITH EVERYONE GETTING AT LEAST LIGHT PRECIP I THINK THERE WILL BE AN AREA OF IN-SITU DAMMING AS MODELS SHOW. CONVECTION AHEAD OF THE STRONG COLD FRONT THEN BEGINS TO MOVE INTO WESTERN AREAS LATE IN THE AFTERNOON...AND SHOULD REALLY BE SPREADING ACROSS THE CWA AFTER 00Z. LOOKS LIKE A FAIRLY QUICK SHOT...00 TO 06Z TIME FRAME...FOR UPSLOPE SO IT LOOKS LIKE WE MAY DODGE A BULLET AS FAR AS ENOUGH RAIN TO CAUSE WIDESPREAD FLOODING PROBLEMS. I RAISED QPF ALONG THE BLUE RIDGE IN NW NC AND FAR SW VA TO AROUND 1.5 INCHES FOR THE EVENT. FFG INDICATES THAT 2 INCHES OR GREATER WOULD LIKELY CAUSE WIDESPREAD PROBLEMS. OTHER CONCERN FOR TONIGHT IS THE STRONG SOUTHERLY LLJ AHEAD OF THIS SYSTEM. MODELS STILL SHOW 60 TO 70 KNOTS AT 850 MB. WE TYPICALLY DO NOT SEE THIS WIND MIX TO THE SURFACE IN OUR CWA EXCEPT WITH CONVECTION...AND WE WOULD BE COVERING THAT SCENARIO IF IT HAPPENS WITH SEVERE THUNDERSTORM WARNINGS SINCE THE HIGH WIND WOULD BE LESS THAN AN HOUR. COULD SEE SOME HIGHER GUSTS ALONG THE RIDGES IN THE FAR WEST WITH SUCH A STRONG SOUTHERLY JET AHEAD OF THE FRONT THOUGH...SO I RAISED THE WIND GUSTS IN THE HIGH ELEVATIONS MAINLY SW MTNS VA AND SE WV TO 30 TO 35 KNOTS. TIMING OF FRONT STILL LOOKED SIMILAR TO PREVIOUS MODEL RUNS...SO I KEPT THE TIMING IN THE GRIDS ABOUT THE SAME- 06 TO 09Z IN THE MTNS...AND 09 TO 12 IN THE PIEDMONT. WILL RE-ISSUE THE SPECIAL WEATHER STATEMENT HIGHLIGHTING THE THREAT OF HEAVY RAIN AND STRONG WIND GUSTS FROM SHOWERS/THUNDERSTORMS TONIGHT. LONG TERM (WEDNESDAY THROUGH MONDAY)... LOOKS LIKE COLD ADVECTION WINDS BEHIND THE FRONT WEDNESDAY WILL LIKELY BE ADVISORY LEVELS IN THE HIGHER ELEVATIONS OF THE NRN MTNS. I DID NOT ISSUE AN ADVISORY FOR THE THIRD PERIOD THOUGH- WOULD BE TOO CONFUSING WITH WIND ADVISORIES TO OUR WEST FOR THE STRONG SOUTHERLY LOW LEVEL JET AHEAD OF THE FRONT LATE THIS AFTERNOON INTO TONIGHT. I LOWERED MAX TEMPERATURES A FEW DEGREES IN THE WEST WITH STRONG COLD ADVECTION. MOISTURE LOOKS SHALLOW IN THE COLD ADVECTION BEHIND THE FRONT BY AFTERNOON. MOST OF ANY MEASURABLE SNOW WILL BE TOWARD MORNING AND THEN THROUGH ABOUT NOON. A SHORT WINDOW...SO ACCUMULATIONS SHOULD BE JUST AN INCH OR TWO. I MADE NO CHANGES TO THE FORECAST BEYOND WEDNESDAY. LOOKS LIKE NEXT THREAT OF RAIN WOULD BE FRIDAY NIGHT AND SATURDAY WITH THE NEXT SYSTEM IN THIS ACTIVE WEATHER PATTERN. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ JH va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 313 PM EST TUE JAN 17 2006 .SHORT TERM (TONIGHT THROUGH WEDNESDAY)... ...MIXED BAG OF PRECIP ON THE WAY... MAIN FORECAST CONCERN THIS EVENING WILL BE TIMING THE CHANGEOVER FROM RAIN TO FROZEN PRECIP...THE TYPE OF PRECIP AND AMOUNTS. COLD FRONT HAS PASSED EASTWARD THROUGH ALMOST THE ENTIRE CWA ATTM. A BLANKET OF LIGHT SHOWERS AND DRIZZLE COVERS LOCATIONS BEHIND THE FRONT...EXTENDING TO WEST OF INTERSTATE 65. IN THE FAR WESTERN CWA...PRECIP ON RADAR HAS A MORE CELLULAR AND WEAKER APPEARANCE TO IT. SFC OBS UPSTREAM ARE REPORTING ANYTHING FROM LIGHT RAIN...TO FREEZING RAIN...TO SLEET AND TO SNOW. EVEN THE BOWLING GREEN SFC OB HAS REPORTED A FEW MINUTES OF SNOW. BASED ON UPSTREAM OBS...ACARS SOUNDINGS AND RUC/NAM/GFS FORECAST SOUNDINGS...LEFTOVER WARM 850MB AIR AND DROPPING SFC TEMPS MAY YIELD A BRIEF PERIOD OF LIGHT SLEET OR FREEZING RAIN THIS EVENING BEFORE CHANGING OVER COMPLETELY TO SNOW. ACARS SOUNDINGS OUT OF SDF SHOW THAT THE LOW-LEVEL COLD AIR IS ABOUT 2KFT DEEP. BASED ON THIS...WILL ONLY MENTION SLEET IN THE ZONES INSTEAD OF SLEET AND FREEZING RAIN. WESTERN CWA LOCATIONS SHOULD HAVE ALL SNOW BY AROUND 23Z...CENTRAL CWA BY 01Z...AND EASTERN CWA BY ROUGHLY 03Z. HAVE TRENDED THIS WAY IN THE GRIDS. SINCE GROUND TEMPS ARE RELATIVELY WARM...DO NOT THINK FROZEN PRECIP WILL ACCUMULATE AT ALL. HOWEVER...GRASSY ELEVATED SURFACES COULD SEE ABOUT A HALF INCH OF SNOW BY MORNING...SO WILL MENTION ACCUMS LESS THAN ONE INCH. ALTHOUGH A MIXED PRECIP SCENARIO LOOKS LIKELY...AMOUNTS JUST WILL NOT ACCUMULATE TO VERY MUCH SO ADVISORY WILL NOT BE ISSUED. HOWEVER...WILL ISSUE AN SPS TO HANDLE THE SITUATION. NAM AND GFS IN PRETTY GOOD AGREEMENT KICKING OUT THE DEEP MOISTURE BY 06Z OVER WRN CWA...AND BY 12Z OVER ERN CWA. HOWEVER...RESIDUAL LOW-LEVEL MOISTURE OVER MY NE CWA IN COMBINATION WITH STRONG SHORTWAVE ENERGY MAY BE ENOUGH TO PRODUCE FLURRIES WEDNESDAY MORNING MAINLY OVER THE BLUEGRASS. CLOUD COVER OVERNIGHT MAY HELP TEMPS FROM DROPPING TOO MUCH...HOWEVER THINK MID TO UPPER 20S IS POSSIBLE...AND AROUND 30 ACROSS BLUEGRASS. MOISTURE SHOULD EXIT THE REGION MID-MORNING WEDNESDAY...AS TEMPERATURES REBOUND BEHIND THE PASSING TROUGH. WEST WINDS WILL AGAIN BE BREEZY TOMORROW...RANGING FROM ABOUT 15-25 MPH AT TIMES. HIGH TEMPS WEDNESDAY LOOK TO RANGE FROM THE UPPER 30S NE TO THE MID 40S SW...WHICH IS CLOSE TO MET GUIDANCE. AL .LONG TERM (WEDNESDAY NIGHT THROUGH TUESDAY)... WEDNESDAY NIGHT THROUGH THURSDAY NIGHT... SHORT RANGE MODELS IN NEAR AGREEMENT...WILL USE NAM12/GFS BLEND THRU THURSDAY. GENERAL SUPPORT FROM UKMET/ECMWF AND CANADIAN MODELS. SMALL DIFFERENCES WITH MOISTURE RETURN LATER THURSDAY INTO EARLY FRIDAY...AND PRECIP DEVELOPMENT WITH THE WARM FRONT ACROSS THE OHIO VALLEY. WILL ALSO BLEND NAM12/MAV MOS FOR TEMPS. SFC HI PRESSURE ACROSS THE SE CONUS LATE WEDNESDAY...WITH MOISTURE PULLING OUT TO THE NORTH AND EAST...FLOW BECOMES MORE WSW BY THURSDAY MORNING...WITH WAA BRINGING A JUMP IN H850 TEMPS FROM NEAR 0C WED EVENING TO AROUND +7C BY THURSDAY AFTERNOON. TEMPS THURSDAY WILL BE NEARLY 15 TO 20 DEGREES ABOVE NORMAL. AS THE DEVELOPING LOW SLIDES ACROSS THE SOUTHERN PLAINS... IT WILL START TO TAP GULF MOISTURE AND PUSH IT UP INTO THE OHIO VALLEY. SOME MID AND UPPER LEVEL CLOUDS WILL DEVELOP ACROSS THE REGION LATER THURSDAY AS THE WARM FRONT SETS UP NEAR OR OVER THE FORECAST AREA. HAVE RAISED DEWPTS SOME. BROUGHT LOW CHC PRECIP POSSIBILITY INTO THURSDAY NIGHT...WEAK ISENTROPIC LIFT VISIBLE...DECENT LOW LEVEL JET WILL BE EXITING THE REGION WITH STRONG UPPER LEVEL JET MOVING ACROSS THE GREAT LAKES...BEST CHANCES LOOKING TO BE ALONG AND NORTH OF THE OHIO RIVER LATE THURSDAY INTO EARLY FRIDAY MORNING WITH ONLY VERY SMALL QPF EXPECTED. FRIDAY THROUGH TUESDAY... EXTENDED MODEL RUNS HAVE BEEN FAIRLY CONSISTENT THROUGH THE LAST WEEK...WITH THE GFS AND NCEP ENSEMBLES LEADING THE WAY. THE ECMWF SEEMS TO BE SLIGHTLY TOO FAST AND WEAK WITH THE NEXT FEW DEVELOPING LOWS ACROSS THE SOUTHERN PLAINS...HAVE THEREFORE FOLLOWED THE SLOWER AND DEEPER GFS/NCEP ENSEMBLE SOLUTION. WILL ALSO LEAN TOWARDS THE NCEP ENSEMBLE MEANS THRU THE EXTENDED...WITH SOMEWHAT LOWER VALUES SUNDAY AND MONDAY. TEMPS STILL REMAIN ABOVE NORMAL THROUGHOUT THE PERIOD AS ALL TELECONNECTIONS CONTINUE TO SHOW WARM TREND THROUGH PERIOD. FRIDAY TEMPS NEARLY 15 DEGREES OR MORE ABOVE NORMAL...WITH REST OF THE PERIOD 8 TO 10 ABOVE NORMAL. AFTER THAT THE TELECONNECTIONS ARE SPLIT...AO STARTS TO TREND SLIGHTLY NEGATIVE AFTER 10 DAYS...NAO THE SAME...WITH THE PNA REMAINING NEUTRAL TO SLIGHTLY POSITIVE THRU THE NEXT 14 DAYS. FOR COLD AIR TO REALLY GRAB HOLD OF THE REGION...NEED THE AMPLIFIED PATTERN THAT THE STRONGLY POSITIVE PNA GENERATES...WITHOUT IT ONLY QUICK HITS OF MODEST COLD AIR WILL MAKE INTO THE REGION AT BEST. STRONG SW FLOW FRIDAY WILL KEEP TEMPS WARM...WITH REGION INTO THE WARM SECTOR AS THE FRONT PUSHES NORTH INTO INDIANA...BEST PRECIP CHCS SHOULD BE NORTH OF THE OHIO RIVER AND EARLY IN THE DAY...WITH THE AFTN SEEING ONLY A SHOWER OR TWO DEVELOP ACROSS THE AREA. COLD FRONT WILL SLIDE ACROSS THE MS RIVER VALLEY LATE FRIDAY INTO SATURDAY MORNING...MOVING OVER THE FORECAST AREA DURING THE LATE MORN SATURDAY INTO THE AFTERNOON HOURS. RAIN SHOWERS WILL BE LIKELY...THO HAVE REMOVED ANY THUNDER WITH ELEVATED LIS ONLY BOTTOMING OUT AROUND +1 OR +2 AND THE FRONT MOVING THRU MOST OF THE FORECAST AREA IN THE MORNING SFC LOW MOVES WELL TO THE NORTH OF THE REGION FROM NEAR OKC FRIDAY NIGHT TO CHI BY SAT MORN INTO ONTARIO CANADA BY EARLY SUNDAY. MODELS HINTING AT DRY SLOT MOVING QUICKLY INTO AREA SAT AFTN/EVEN...WILL CLEARING QUICKLY AS MOISTURE PULLS RAPIDLY OFF TO THE NORTH AND EAST. SFC HIGH PRESSURE WILL DOMINATE THE REGION SUNDAY INTO TUESDAY...WITH CURRENT MODEL TRENDS KEEPING SYSTEMS IN THE SOUTHERN STREAM TO THE SOUTH OF THE FORECAST AREA. SCHOTT && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 422 PM EST TUE JAN 17 2006 .DISCUSSION... THE MAIN FORECAST CONCERNS ARE WITH SNOWFALL AMOUNTS ACROSS THE CWA OVER THE NEXT FEW PERIODS. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A CLOSED LOW EMBEDDED IN A LONGWAVE TROUGH OVER THE MISSISSIPPI RIVER VALLEY AND MANITOBA ONTARIO. BROAD RIDGES ARE OVER THE EAST COAST AND THE NORTHERN HIGH PLAINS. WEAK SHORTWAVES MOVING THROUGH LONGWAVE TROUGH ARE OVER THE FORECAST AREA...AND OVER MINNESOTA. OTHER WEAK SHORTWAVES ARE BEING EJECTED OUT AHEAD OF THE TROUGH. SURFACE ANALYSIS INDICATE A CLOSED LOW OVER LOWER MICHIGAN WITH A FRONT DRAPED TO THE SOUTH THROUGH THE OHIO RIVER VALLEY AND AN INVERTED TROUGH STRETCHING NORTH THROUGH WESTERN ONTARIO. A SURFACE RIDGE EXTENDS FROM THE CENTRAL PLAINS THROUGH THE DAKOTAS INTO EASTERN MANITOBA. ANOTHER SURFACE LOW IS OVER BRITISH COLUMBIA WITH A SURFACE TROUGH EXTENDING ACROSS EASTERN MONTANA AND THROUGH THE NORTHERN HIGH PLAINS. THE LONGWAVE TROUGH WILL MOVE OVER THE UPPER GREAT LAKES TONIGHT. THE SHORTWAVE OVER THE FORECAST AREA WILL MOVE INTO EASTERN ONTARIO WHILE ANOTHER SLIDES INTO THE WEST END. THE SURFACE LOW OVER LOWER MICHIGAN WILL SHIFT OVER GEORGIAN BAY OVERNIGHT DRAGGING THE COLD FRONT INTO THE EAST COAST AND THE INVERTED TROUGH INTO JAMES BAY. THE FLOW BEHIND THIS LOW WILL DRAW COOLER AIR INTO THE REGION. AN 850MB THERMAL TROUGH WILL MOVE OVER LAKE SUPERIOR GENERATING A LAKE-850MB DELTA-T OF AROUND 15C. SURFACE-850MB RH WILL BE >90 PERCENT. HOWEVER...WE WILL BE LOSING THE SURFACE CONVERGENCE AND ANY TRIGGERING MECHANISM. STILL SHOULD BE ENOUGH UPPER LEVEL INSTABILITY TO GENERATE SNOW. ISENTROPIC ANALYSIS INDICATE STRONG SUBSIDENCE ACROSS THE REGION TONIGHT. LAKE EFFECT SNOW DECISION TREE COMBINED WITH THE GARCIA METHOD ONLY INDICATES SNOWFALL WILL BE ON THE ORDER OF 2 TO 4 INCHES OVERNIGHT WITH THE HEAVIEST SNOW OVER THE EASTERN U.P. THE HEAVIEST LES WILL BE OVER THE NORTHERN COUNTIES. THE LONGWAVE TROUGH WILL MOVE INTO WESTERN QUEBEC ON WEDNESDAY. A SHORTWAVE MOVING THROUGH THE BASE OF THIS TROUGH WILL SWEEP INTO EASTERN ONTARIO. THE SURFACE LOW WILL CONTINUE INTO CENTRAL QUEBEC...WHILE THE SURFACE RIDGE MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE THERMAL TROUGH WILL INCREASE THE DELTA-T'S TO AROUND 17C. WITH A NORTHWESTERLY FLOW...LAKE EFFECT SNOWS WILL CONTINUE ALONG THE NORTH SHORE WITH THE HEAVIEST LAKE EFFECT SNOWS IN AREA FAVORED BY A NORTHWEST FLOW. A SURFACE LOW WILL PUSH INTO THE NORTHERN PLAINS. THE LONGWAVE TROUGH WILL PROCEED EAST ON WEDNESDAY NIGHT...WHILE A SHORTWAVE SHIFTS INTO NORTHERN WISCONSIN AND SOUTHERN MINNESOTA. ANOTHER SHORTWAVE WILL DEVELOP OVER THE DAKOTAS. THE SURFACE TROUGH IS OVER SOUTHERN MANITOBA THROUGH MINNESOTA. A FIELD OF LOW LEVEL MOISTURE WILL SLIDE INTO THE WESTERN U.P. LATE. THE WIND WILL BACK TO THE WEST. THE ISENTROPIC ASCENT OVER THE WESTERN U.P. AHEAD OF THE LOW...THE MOISTURE FIELD AND WEAK SHORTWAVE ENERGY WOULD PRODUCE SOME LIGHT SNOW OVER THE WEST. A SHORTWAVE WILL SLIDE FROM THE DAKOTAS INTO EASTERN MINNESOTA THURSDAY NIGHT WHILE DIRECTING A LITTLE WEAKER SHORTWAVE ACROSS THE FORECAST AREA. A DEEPER SHORTWAVE WILL BEGIN TO DIG OVER THE FOUR CORNERS AREA. SURFACE LOW WILL MOVE INTO THE U.P. WHILE ANOTHER LOW DEEPENS OVER NORTHEAST NEW MEXICO. THIS WILL CAUSE LIGHT SNOW TO SPREAD ACROSS THE FORECAST AREA. THE SHORTWAVE WILL SLIDE OFF TO THE EAST...WHILE THE NORTHEAST NEW MEXICO LOW WILL SHIFT INTO CENTRAL KANSAS...WHILE THE SURFACE LOW MOVES TO KMCI. A SURFACE RIDGE WILL SETTLE OVER THE FORECAST AREA. COLD AIR AND WEAK LOW LEVEL ASCENT WILL KEEP THE POTENTIAL OF LAKE EFFECT SNOWS GOING FOR LAKE SUPERIOR. IN THE EXTENDED...I FAVOR THE 00Z GFS AS PER NCEP DISCUSSION. THE MID LEVEL CLOSED LOW OVER EASTERN KANSAS WILL MOVE INTO EASTERN IOWA...WHILE THE SURFACE LOW RACES INTO NORTHEAST ILLINOIS DRAGGING A COLD FRONT THROUGH THE LOWER MISSISSIPPI RIVER VALLEY AND DIRECTING A WARM FRONT INTO LOWER MICHIGAN. A RIDGE WILL CONTINUE ACROSS LAKE HURON AND LAKE SUPERIOR. 295K ISENTROPIC ASCENT AHEAD OF THE WARM FRONT WILL INCREASE ACROSS THE FORECAST AREA OVERNIGHT. THICKNESS SUGGEST THAT CONDITION REMAIN COLD ENOUGH TO PRODUCE SNOW. THE SHORTWAVE WILL SLIDE INTO EASTERN ONTARIO LEADING THE SURFACE LOW AND ASSOCIATED FRONT TO THE EAST OF LAKE HURON. THUS CONDITIONS LOOK FAVORABLE FOR SNOW TO SPREAD INTO THE FORECAST AREA LATE FRIDAY NIGHT INTO SATURDAY. A WEAK MID LEVEL RIDGE AND ACCOMPANYING SURFACE RIDGE WILL SLIDE INTO THE FORECAST AREA SATURDAY NIGHT...BRINGING IN DRIER AND MORE STABLE CONDITIONS. A WEAK SHORTWAVE AND ACCOMPANYING SURFACE LOW WILL MOVE ACROSS CENTRAL ONTARIO AND NORTHERN LAKE SUPERIOR ON SUNDAY. MODELS SHOWING LOW LEVEL MOISTURE AROUND 80 PERCENT WILL CONTINUE OVER THE THE U.P. AND LAKE SUPERIOR. TOGETHER THESE MAY PRODUCE SOME LIGHT SNOW. A RIDGE WILL SHIFT ACROSS THE FORECAST AREA SUNDAY NIGHT...FOLLOWED BY ANOTHER SHORTWAVE MONDAY NIGHT AND TUESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING IN EFFECT FOR EAST HALF OF LAKE SUPERIOR FOR LSZ260. && $$ DLG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 1233 PM EST TUE JAN 17 2006 .AVIATION... OVERALL MVFR CONDITIONS ACROSS THE REGION WILL PERSIST FROM LWB...ROA AND LYH THIS AFTERNOON WHILE IMPROVING TO VFR AT BLF/DAN BEFORE MAIN AXIS OF SHRA ARRIVES WITH THE FRONT THIS EVENING. APPEARS MAY CONCERN WITH LOW LEVEL WIND SHEAR GIVEN JET ALOFT AND RATHER LIGHT WINDS AT EASTERN SITES ATTM. THUS WILL INCLUDE WIND SHEAR MOST SPOTS THRU EARLY THIS EVENING. FRONT ROLLS ACROSS WITH AREA OF SHRA THIS EVENING THRU ABOUT 09Z WITH MVFR/IFR CEILINGS/VSBYS IN ORDER. UPSLOPE POST FRONTAL -SHSN WILL KICK IN ACROSS THE SE WVA SITES EARLY WED WHILE IMPROVING CONDITIONS RESULT IN VFR EASTERN LOCATIONS AFTER 12Z. HOWEVER STRONG POST FRONTAL WEST WINDS WILL PROMPT SOME SPOTS TO SEE GUSTS ABOVE 30 KTS INTO WED AFTERNOON. && SHORT TERM (REST OF THIS AFTERNOON) BASED ON CURRENT OBS FROM AROUND BLF...HAVE SENT A QUICK UPDATE TO RAISE A WIND ADVISORY FOR 3 COUNTIES IN THE SW THRU THIS EVENING. THIS IN CONJUNCTION WITH SOUTHERLY WINDS ACROSS THE RIDGES AHEAD OF THE APPROACHING COLD FRONT. FEW ADDITIONAL CHANGES FOR NOW. .PREVIOUS DISCUSSION... (ISSUED 1014 AM EST TUE JAN 17 2006) SHORT TERM (REST OF TODAY)... ANALYSIS SHOWING WARM FRONT DANGLING ACROSS THE FAR SOUTHERN/SW PORTION OF THE CWA THIS MORNING WITH RAINFALL INDUCED WEDGE IN PLACE. MAIN AXIS OF RAINFALL WITH THIS FEATURE NOW PUSHING NORTH OF HIGHWAY 460 ASSOCIATED WITH INITIAL SLUG OF ISENTROPIC LIFT. MAIN QUESTIONS THIS AFTERNOON WITH EASTWARD EXTENT OF SHRA AHEAD OF THE COLD FRONT NOW APPROACHING THE TN VALLEY AND HOW STRONG WEDGE WILL BE AS WAA ALOFT ATTEMPTS TO MIX DOWN. LATEST RUC/WRF SUGGEST THAT THE MAJORITY OF THE LIFT WILL STAY TO THE WEST/NORTH THIS AFTERNOON ONCE THIS BATCH OF -RA EXITS AND FRONTAL SHRA GETS DELAYED AS NEXT S/W RIDES UP THE BOUNDARY. LESS PRECIP SHOULD ALSO ACT TO HELP WEDGE SLOWLY ERODE FROM SOUTH TO NORTH BUT WILL BE A SLOW PROCESS WITH LOCATIONS IN THE SHENANDOAH VALLEY LIKELY STAYING IN THE COLD POOL. WINDS ALSO AN ISSUE WHERE WARM AIR HAS SCOURED OUT THE WEDGE IN THE FAR WEST ALTHO THINK INCREASING TO JUST BELOW ADVISORY LEVELS WILL WORK FOR NOW GIVEN LIGHT PRECIP IN THE AREA. OTHERWISE WILL CONTINUE THE TREND OF ONLY CHANCE POPS ALL EXCEPT FAR NW EARLY ON...THEN INCREASING OVER THE WEST BY MID/LATE AFTERNOON AHEAD OF THE FRONT. MAY REMOVE TSRA MENTION FAR W GIVEN LACK OF INSTAB AND TREND OF MORE LOW TOPPED CONVECTION TO THE WEST. HIGH TEMPS LIKELY MORE OF A LATE AFTERNOON SCENARIO AS WARM AIR ALOFT DEEPENS AND MIXING INCREASES. MAY LOWER HIGHS SOME IN THE WEDGE REGIONS OTHERWISE ONLY SOME SLIGHT CHANGES. PREVIOUS DISCUSSION... (ISSUED 650 AM EST TUE JAN 17 2006) AVIATION... OVERRUNNING RAIN WILL BE AFFECTING ALL OF THE TAF SITES THIS MORNING- HEAVIEST AT BLF AND LWB. CIGS ARE EXPECTED TO COME DOWN TO MVFR OR IFR...VSBYS TO MVFR. ALL TAF SITES WILL LIKELY STAY DOWN AT LEAST TO MVFR...BUT DAN AND BLF MAY REACH VFR CIGS THIS AFTERNOON. MAIN CONCERN BEFORE THE PRECIPITATION MOVES IN AHEAD OF THE STRONG COLD FRONT WILL BE FOR LLWS. THINK THAT SURFACE WINDS WILL STAY FAIRLY LOW- PARTICULARLY IN A COLD AIR WEDGE THAT HAS DEVELOPED FROM THE LIGHT RAIN. WINDS JUST A FEW THOUSAND FEET ABOVE THE SURFACE WILL INCREASE TO 35 OR 40 KNOTS THIS AFTERNOON AND INTO THIS EVENING. TIMED THE FRONT THROUGH OVERNIGHT WITH WINDS SHIFTING FROM THE SOUTHEAST AND SOUTH TO THE WEST. STRONG WINDS IN THE COLD ADVECTION BEHIND THE FRONT LOOK TO HOLD OFF TILL AFTER 12Z. PREVIOUS DISCUSSION... (ISSUED 341 AM EST TUE JAN 17 2006) SHORT TERM (TODAY THROUGH TONIGHT)... FIRST ORDER OF BUSINESS IS THE OVERRUNNING RAIN SPREADING NEWD ACROSS THE CWA AHEAD OF A WARM FRONT. BEST ISENTROPIC LIFT REMAINS TO THE WEST TODAY...BUT IT APPEARS THAT SOME LIGHT RAIN MAY EVEN AFFECT THE VA PIEDMONT THIS MORNING. I HAVE RAISED THE POPS TO INCLUDE A PERIOD OF AT LEAST LIKELY POPS EVERYWHERE THIS MORNING. SHOULD NOT BE MUCH PRECIP IN THE EAST...GENERALLY A TENTH OF AN INCH OR LESS...BUT I THINK IT WILL MEASURE. MODELS NOW SHOWING THE THE RAIN LASTING INTO AFTERNOON IN THE VA HIHGLANDS AND GREENBRIER AREA...SO I EXTENDED THE HIGHER POPS INTO THE AFTERNOON. OTHER BIG CHANGE TO THE FORECAST IS TO LOWER TEMPS EAST OF THE MTNS ESPECIALLY IN THE VA PIEDMONT AND IN VA HIGHLANDS AND GREENBRIER VALLEY WITH EVERYONE GETTING AT LEAST LIGHT PRECIP I THINK THERE WILL BE AN AREA OF IN-SITU DAMMING AS MODELS SHOW. CONVECTION AHEAD OF THE STRONG COLD FRONT THEN BEGINS TO MOVE INTO WESTERN AREAS LATE IN THE AFTERNOON...AND SHOULD REALLY BE SPREADING ACROSS THE CWA AFTER 00Z. LOOKS LIKE A FAIRLY QUICK SHOT...00 TO 06Z TIME FRAME...FOR UPSLOPE SO IT LOOKS LIKE WE MAY DODGE A BULLET AS FAR AS ENOUGH RAIN TO CAUSE WIDESPREAD FLOODING PROBLEMS. I RAISED QPF ALONG THE BLUE RIDGE IN NW NC AND FAR SW VA TO AROUND 1.5 INCHES FOR THE EVENT. FFG INDICATES THAT 2 INCHES OR GREATER WOULD LIKELY CAUSE WIDESPREAD PROBLEMS. OTHER CONCERN FOR TONIGHT IS THE STRONG SOUTHERLY LLJ AHEAD OF THIS SYSTEM. MODELS STILL SHOW 60 TO 70 KNOTS AT 850 MB. WE TYPICALLY DO NOT SEE THIS WIND MIX TO THE SURFACE IN OUR CWA EXCEPT WITH CONVECTION...AND WE WOULD BE COVERING THAT SCENARIO IF IT HAPPENS WITH SEVERE THUNDERSTORM WARNINGS SINCE THE HIGH WIND WOULD BE LESS THAN AN HOUR. COULD SEE SOME HIGHER GUSTS ALONG THE RIDGES IN THE FAR WEST WITH SUCH A STRONG SOUTHERLY JET AHEAD OF THE FRONT THOUGH...SO I RAISED THE WIND GUSTS IN THE HIGH ELEVATIONS MAINLY SW MTNS VA AND SE WV TO 30 TO 35 KNOTS. TIMING OF FRONT STILL LOOKED SIMILAR TO PREVIOUS MODEL RUNS...SO I KEPT THE TIMING IN THE GRIDS ABOUT THE SAME- 06 TO 09Z IN THE MTNS...AND 09 TO 12 IN THE PIEDMONT. WILL RE-ISSUE THE SPECIAL WEATHER STATEMENT HIGHLIGHTING THE THREAT OF HEAVY RAIN AND STRONG WIND GUSTS FROM SHOWERS/THUNDERSTORMS TONIGHT. LONG TERM (WEDNESDAY THROUGH MONDAY)... LOOKS LIKE COLD ADVECTION WINDS BEHIND THE FRONT WEDNESDAY WILL LIKELY BE ADVISORY LEVELS IN THE HIGHER ELEVATIONS OF THE NRN MTNS. I DID NOT ISSUE AN ADVISORY FOR THE THIRD PERIOD THOUGH- WOULD BE TOO CONFUSING WITH WIND ADVISORIES TO OUR WEST FOR THE STRONG SOUTHERLY LOW LEVEL JET AHEAD OF THE FRONT LATE THIS AFTERNOON INTO TONIGHT. I LOWERED MAX TEMPERATURES A FEW DEGREES IN THE WEST WITH STRONG COLD ADVECTION. MOISTURE LOOKS SHALLOW IN THE COLD ADVECTION BEHIND THE FRONT BY AFTERNOON. MOST OF ANY MEASURABLE SNOW WILL BE TOWARD MORNING AND THEN THROUGH ABOUT NOON. A SHORT WINDOW...SO ACCUMULATIONS SHOULD BE JUST AN INCH OR TWO. I MADE NO CHANGES TO THE FORECAST BEYOND WEDNESDAY. LOOKS LIKE NEXT THREAT OF RAIN WOULD BE FRIDAY NIGHT AND SATURDAY WITH THE NEXT SYSTEM IN THIS ACTIVE WEATHER PATTERN. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY FOR VAZ007-010 UNTIL 9 PM TUESDAY. NC...NONE. WV...WIND ADVISORY FOR WVZ042 UNTIL 9 PM TUESDAY. && $$ JH va