AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 820 PM EST FRI DEC 24 2004 .SYNOPSIS... COLD FRONT APPEARS TO BE HUNG UP IN THE MIAMI-DADE AREA. SHORTWAVE IN NORTHERN MEXICO SEEMS TO HAVE MADE THE TURN TOWARDS THE EAST AND HAS PLUNGED AS FAR SOUTH AS IT GOING TO GO. DEEP MOISTURE CONTINUES TO FLOW TOWARDS THE NORTHEAST ACROSS THE NORTHERN HALF OF THE GULF OF MEXICO. THE RUC IS ANALYZING A CLOSED LOW AROUND 93W ALONG THE STATIONARY FRONT. NORTHERLY FLOW CONTINUES ACROSS THE CWA. SURFACE TEMPS HAVE CHANGED VERY LITTLE ACROSS THE CWA DURING THE LAST FEW 5-6 HOURS RANGING FROM 37F AT DHN TO 42F AT CTY. DEWPOINTS HAVE CHANGED VERY LITTLE ALSO...BEING SOMEWHAT LOWER ON THE WEST SIDE OF THE CWA. A LARGE AREA OF LIGHT PRECIP CONTINUES TO STREAM ACOSS THE CWA. ALOFT...WE STILL SHOW A DEEP WARMER THAN 0C LAYER AS SHOWN BY OUR SOUNDING. FREEZING LEVEL IS NEARLY 10K FT. && .SHORT TERM... HAD SOME CONCERNS EARLIER ABOUT THE POSSIBILITY OF ISSUING ANOTHER WINTER WEATHER ADVISORY...ESPECIALLY IN SOUTHEAST AL AND FL PANHANDLE. BUT THE SOUNDING AND THE STEADY TEMPS HAVE EASED MY MIND SOMEWHAT. ZONES APPEAR TO BE ON TRACK AND ANTICIPATE VERY LITTLE CHANGES. && .MARINE...WINDS AND SEAS REMAIN IN CAUTION RANGE AS ANTICIPATED IN THE CWF. WINDS HOWEVER ARE RUNNING ABOUT 5 KTS STRONGER THAN PREDICTED. WILL MAKE THOSE CHANGES IN THE 1030PM UPDATE. && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. && $$ WATSON fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 316 PM EST FRI DEC 24 2004 .DISCUSSION... THE MAIN CONCERN FOR THIS FORECAST PACKAGE IS THE SNOW POTENTIAL FOR TONIGHT AND CHRISTMAS. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A CLOSED LOW OVER NORTHERN ONTARIO EMBEDDED IN A LONGWAVE TROUGH OVER EASTERN CANADA AND CONUS. A BROAD RIDGE BLANKETS THE NORTHERN ROCKIES. A CLOSED LOW SWINGING THROUGH THE BASE OF THE LONGWAVE TROUGH IS OVER NORTHERN MEXICO. WEAK SHORTWAVES MOVING THROUGH THE BASE OF THE LONGWAVE TROUGH ARE OVER EASTERN U.P. AND OVER SOUTHERN MANITOBA. SURFACE ANALYSIS INDICATE A RIDGE OVER THE MIDDLE MISSISSIPPI RIVER VALLEY STRETCHING NORTH THROUGH THE UPPER GREAT LAKES INTO CENTRAL ONTARIO. AN ELONGATED SURFACE TROUGH STRETCHES FROM THE CANADIAN ROCKIES INTO THE DAKOTAS. REMNANTS OF A WEAK FRONT REMAINS OVER UPPER MICHIGAN CAUSING LOW LEVEL CONVERGENCE ACROSS THE LAKE. 850MB TEMPERATURE ARE AROUND -21C ACROSS LAKE SUPERIOR CAUSING A SIGNIFICANT LAPSE RATE AND GENERATE SCATTERED LAKE EFFECT SNOW SHOWERS. THE ONTARIO MID LEVEL LOW WILL EDGE SOUTHEAST A FEW MILES OVERNIGHT. A WEAK SHORTWAVE WILL SLIDE ACROSS LAKE SUPERIOR. THE SURFACE LOW OVER THE CANADIAN ROCKIES WILL SLIDE INTO THE DAKOTAS. A WEAK FRONTAL SYSTEM WILL REMAIN STATIONARY ACROSS SOUTHERN LAKE SUPERIOR. CYCLONIC FLOW AROUND THE LOW OVER THE DAKOTAS IS CAUSING THE WINDS TO SHIFT SOUTHWEST. THE WEAK FRONTAL SYSTEM OVER LAKE SUPERIOR WILL WASH OUT AND THE LOW LEVEL CONVERGENCE IS EXPECTED TO WEAKEN AS WELL. GFS/ETA BOTH SHOW THE CONVERGENCE REMAINING OVER EASTERN LAKE SUPERIOR THIS EVENING. THE WINDS WILL BECOME ANTI-CYCLONIC OVER THE CENTRAL U.P. TONIGHT. 950MB INDICATE DRIER AIR SPREADING INTO THE CENTRAL U.P. MORE STABLE CONDITIONS...WIND BACKING WEST AND DRIER AIR ENTERING THE AREA...IT LOOKS SAFE TO KEEP THE LES GOING THIS EVENING ESPECIALLY OVER THE KEWEENAW PENINSULA AND NORTHEAST CWA...BUT DIMINISHING IT BY MIDNIGHT. THE CLOSED LOW OVER NORTHERN ONTARIO WILL SHIFT CLOSER TO JAMES BAY ON SATURDAY. ANOTHER SHORTWAVE WILL DEVELOP ON ITS FLANK AND SWEEP INTO NORTHERN LAKE SUPERIOR. THE DAKOTA SURFACE LOW WILL SHIFT DEEPER IN TO THE PLAINS WITH A TROUGH EXTENDING NORTHEAST INTO THE U.P. A SURFACE RIDGE WILL BLANKET NORTHERN ONTARIO AND CENTRAL QUEBEC. THE 850MB TEMPERATURE OVER LAKE SUPERIOR WILL LOWER TO 19C AND 925MB RH WILL REMAIN AROUND 80 PERCENT. WINDS WILL VEER SOUTH ENDING ANY LES OVER THE NORTHERN U.P. HOWEVER...WITH A SOUTHERLY COMPONENT...SURFACE-850MB DELTA-T'S OVER 20C+ MODELS SHOWING LOW LEVEL CONVERGENCE OVER THE DOOR PENINSULA. CONDITIONS LOOK FAVORABLE FOR LES ALONG THE NORTH LAKE MICHIGAN SHORE. CYCLONIC FLOW ACROSS LAKE SUPERIOR ALSO SUPPORTS SOME CONVERGENCE OF EASTERN LAKE SUPERIOR. THUS LAKE EFFECT SNOW WILL KICK BACK IN. THIS TIME WITH SNOWFALL OVER THE LES PRONE AREAS WITH A NORTHEAST FLOW. THE NORTHERN LAKE SUPERIOR SHORTWAVE WILL SHIFT ACROSS THE FORECAST AREA ON SUNDAY MORNING. A SURFACE RIDGE WILL PUSH INTO ONTARIO AND MINNESOTA CAUSING THE WINDS TO BECOME ANTI-CYCLONIC LATE SUNDAY MORNING...DEVELOPING STRONG DIVERGENCE OVER THE AREA. A LITTLE DRIER AND COLDER AIR MASS IS PROGGED TO SPREAD ACROSS THE LAKE. DELTA-T'S STILL AROUND 24C WILL KEEP BANDS OF THE LES GOING FOR MUCH OF THE AREA SUNDAY AFTERNOON...HOWEVER...WITH DIVERGENCE AND DRIER AIR... SNOWFALL WILL BECOME LIMITED. A WEAK SHORTWAVE WILL SHIFT ACROSS THE U.P. SUNDAY NIGHT. A SURFACE RIDGE WILL SHIFT ACROSS THE AREA. DELTA-T'S WILL REMAIN AROUND 20C. THE WINDS WILL VEER SOUTH AND STRONG DIVERGENCE OVER THE AREA WILL END LAKE EFFECT SNOWS. HOWEVER...WITH THE INSTABILITY OF THE SHORTWAVE PASSING OVER THE AREA. BOTH ETA/GFS SHOWING MEAN SURFACE-500MB BETWEEN 75 AND 95 PERCENT ACROSS THE AREA. THIS SHOULD BE ADEQUATE TO PRODUCE SOME SYSTEM TYPE SNOW ACROSS THE AREA. THE QUESTION IS IF THE SURFACE RIDGE WILL BE STABLE ENOUGH TO KEEP THE PRECIPITATION FROM OCCURRING. GFS SUGGEST KEEP PRECIPITATION IN WHILE ETA CONSIDER IT TO DRY. NCEP FAVOR THE ETA SOLUTION. PLAN TO KEEP A CHANCE GOING. ETA/GFS SHOWING A WEAK SHORTWAVE MOVING ACROSS THE FORECAST AREA ON MONDAY. GFS SHOWING A DEEPER SHORTWAVE PASSING OVER NORTHEAST LAKE SUPERIOR. SURFACE RIDGE WILL SHIFT OFF TO THE EAST. DELTA-T'S STILL AROUND 16C. HOWEVER...THE WINDS WILL BE OUT OF THE SOUTHWEST BEHIND THE RIDGE. ETA BRINGING LOW LEVEL MOISTURE AND A SHORTWAVE INTO THE FORECAST AREA LATE ON MONDAY...WHEREAS GFS KEEP THIS TO THE NORTHEAST OF THE FORECAST AREA. THE DGEX MODEL SUGGEST KEEPING IT IN. SINCE THE SNOW IS IN THE FORECAST ALREADY WILL NOT TAKE IT OUT SINCE I LACK ENOUGH CONFIDENCE IN LATEST ETA. THE MID LEVEL SHORTWAVE WILL MOVE INTO MANITOBA AND THE NORTH PLAINS AS A WEAK SHORTWAVE SLIDES OVER THE U.P. A COLD FRONT WILL SLIDE INTO THE MINNESOTA. ISENTROPIC ASCENT AHEAD OF THE FRONT WILL GENERATE A CHANCE FOR SOME SNOW MONDAY NIGHT. THE SHORTWAVE AND COLD FRONT WILL BECOME MORE PRONOUNCED AS THEY SWINGS THROUGH THE FORECAST AREA ON TUESDAY AND TUESDAY NIGHT. A SURFACE RIDGE WILL SHIFT OVER THE FORECAST AREA ON WEDNESDAY AND MOVE QUICKLY TO THE MID ATLANTIC STATES. A WEAK MID LEVEL RIDGE WILL MOVE ACROSS THE FORECAST AREA AND MOVE NORTHEAST. ANTI-CYCLONIC FLOW BEHIND THE FRONT WILL DRAW WARMER AIR INTO THE AREA. THE MID LEVEL RIDGE WILL BUILD OVER THE GREAT LAKES THROUGH THURSDAY WHILE SURFACE LOW MOVES INTO MINNESOTA DRAGGING A COLD FRONT INTO THE MIDDLE MISSISSIPPI RIVER VALLEY. THE SURFACE LOW WILL TRACK ACROSS THE FORECAST AREA ON FRIDAY. INSTABILITY ACCOMPANYING THIS SYSTEM SHOULD GENERATE SOME PRECIPITATION. GFS INDICATE THAT THE 850MB TEMPERATURES WILL BE AROUND ZERO OVER THE AREA. THINK GFS IS WARMING THE AIR TOO MUCH SO WILL KEEP JUST A CHANCE OF EACH. GFS EXTENDED MOS LOOKING FOR SURFACE TEMPERATURES AROUND 0C. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 11 PM EST THIS EVENING MIZ001-003. && $$ DLG mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE MARQUETTE MI 1045 AM EST FRI DEC 24 2004 .DISCUSSION... OBVIOUS CONCERN WITH THIS UPDATE IS CURRENT LES AND HEADLINES. THE HEADLINE FOR ALGER COUNTY IS SET TO EXPIRE AT 11 AM...AND WILL PROBABLY CANCEL IT AT THAT TIME. PESKY MESO-VORTEX OVER EASTERN LAKE SUPERIOR IS CONTINUING TO PRODUCE SIGNIFICANT CONVERGENCE AND LES OVER FAR EASTERN ALGER COUNTY AND NORTHWEST LUCE COUNTY...BUT EXPECT THE MESO-VORTEX TO SLOWLY LOST SOME OF ITS STRUCTURE THROUGHOUT THE DAY AS THE ADJACENT LAND MASSES WARM SOME AND THE LAND BREEZES RELAX. THE 12Z ETA AND LOCAL WORKSTATION ETA BOTH KEEP SNOW SHOWER ACTIVITY GOING ACROSS THIS AREA THROUGH THE AFTERNOON...BUT SUGGEST A WEAKENING TREND. AMOUNTS OVERNIGHT AS HIGH AS 8 INCHES WERE REPORTED FROM MUNISING. FEEL ADDITIONAL AMOUNTS THIS AFTERNOON WILL BE MINIMAL OVER MOST OF ALGER COUNTY...WITH 1 TO LOCALLY 4 INCHES POSSIBLE NEAR GRAND MARAIS DUE TO THE BANDING ON THE SOUTH SIDE OF THE MESO-VORTEX. WILL MENTION THESE ACCUMULATIONS IN THE FORECAST UPDATE...BUT ALLOW THE HEADLINE TO BE CANCELLED. OVER THE KEWEENAW...HEAVY SNOW HAS BEEN REPORTED AT KCMX FOR MUCH OF THE MORNING WITH A FAVORABLE WEST WIND BRINGING SNOW TO NORTHERN HOUGHTON COUNTY. SNOWFALL OVER THE NORTHERN KEWEENAW HAS BEEN LIMITED DUE TO THE PERSISTING NORTHWEST WIND IN THAT AREA...BUT WOULD EXPECT THE HEAVIER SNOWFALL TO SHIFT SLOWLY INTO THAT AREA THROUGH THE AFTERNOON AS THE BOUNDARY LAYER FLOW BECOMES MORE SOUTHWESTERLY. THINGS ACROSS THE ENTIRE CWFA ARE CURRENTLY BEING ENHANCED BY THE SHORTWAVE WHICH CAN BE SEEN IN THE WATER VAPOR IMAGERY AND RUC ANALYSES SWINGING ACROSS LAKE SUPERIOR. INVERSION HEIGHTS ARE EXPECTED TO DESCEND...WITH ATTENDANT DRYING...LATER THIS AFTERNOON AND THIS EVENING...WITH SOMEWHAT UNFAVORABLE FLOW AND THERMODYNAMICS PROGGED OVER THE KEWEENAW BY EARLY EVENING. THIS WILL HAVE TO BE EVALUATED FURTHER...SINCE IT MAY ALLOW FOR THE KEWEENAW HEADLINE TO BE SHORTENED. TEMPERATURES ACROSS THE CWFA ARE SLOW TO REBOUND THIS MORNING...AND HAVE TWEAKED BACK FORECAST HIGHS A BIT TO LINE UP BETTER WITH CURRENT TRENDS. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 11 PM EST THIS EVENING MIZ001-003. && $$ TRH mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE MARQUETTE MI 515 AM EST FRI DEC 24 2004 .DISCUSSION... MAIN FCST CONCERNS ARE LES TRENDS AND WIND CHILLS. WV IMAGERY AND RUC ANALYSIS INDICATED A HIGH AMPLITUDE PATTERN WITH A RDG FROM THE EPAC INTO THE PAC NW AND A LONG WAVE TROF AXIS FROM HUDSON BAY THROUGH THE WRN LAKES TOWARD THE SRN PLAINS. AN UPSTREAM SHRTWV OR SHEAR AXIS EXTENDED FROM NW ONTARIO TO W LK SUPERIOR. AT THE SFC...ARCTIC HIGH PRES STRETCHED FROM NRN MANITOBA TOWARD THE SRN PLAINS WHILE A LAKES INDUCED TROF EXTENDED FROM NRN LK MI NW TO S AND W LK SUPERIOR. RADAR INDICATED CONVERGENT BAND OF SHSN INTO E ALGER COUNTY. TODAY AND TONIGHT...WHILE 850 TO 700 MB TEMPS (-24C TO -34C) PRODUCED VERY STRONG INSTABILITY...SNOW GROWTH IN SUCH AN ARCTIC AIRMASS WOULD BE NORMALLY BE UNFAVORABLE. HOWEVER...THERMAL RDGING MOISTURE/HEAT FLUX IN DOMINANT/CONVERGENT BANDS VCNTY TROF...SHOULD STILL LEAD TO DECENT SNOWFLAKE GROWTH. OVER THE WEST...ETA FCST 950 CONV KEEPS FOCUS VCNTY KCMX THIS MORNING BEFORE SHIFTING NORTH TO NEAR KP59 THIS EVENING. SO EXPECT LOCAL SNOWFALL RATES TO AT LEAST AN INCH/HOUR TODAY. SHIFTING POSITION OF SNOW BAND SHOULD LIMIT OVERALL ACCUMULATIONS INTO THE 3-7 INCH RANGE. ETA LOW LVL WINDS ALSO SUGGEST E LAKE CONVERGENCE BAND WILL GRADUALLY SHIFT EASTWARD. ENOUGH UNCERTAINTY ON EVOLUTION OF MESO-LOW REMAINS TO JUSTIFY CONTINUED SCT/NMRS SHSN NEAR THE SHORE INTO THIS EVENING EVEN IF ETA SUGGESTS LES WILL MOVE OFF SHORE. MIXING IN AREAS WITH WINDS AOA 10 MPH HAS KEPT TEMPS UP WHILE COLDEST READINGS WERE GENERALLY IN LOCATIONS WITH WINDS BLO 10 MPH. SO...EVEN WITH CURRENT WIND CHILLS MAINLY IN THE 15 TO 25 BELOW RANGE...PREVAILING CONDITIONS ABV ADVY CRITERIA (25 BELOW...WINDS AOA 10 MPH) EXPECTED AS TEMPS SLOWLY REBOUND THIS MORNING. EVEN THOUGH ARCTIC AIRMASS REMAINS OVER UPR MICHIGAN...ENOUGH WAA CLOUDS MAY LIMIT RADIATIONAL COOLING. NEVERTHELESS...INLAND READINGS FCST INTO THE -12F TO -17F RANGE WITH TEMPS NEAR ZERO ALONG THE LAKE SHORES. SATURDAY...WHILE THE ETA SHOWS BEST SATURATION WITH 280K-290K ISENTROPIC LIFT SLIDING SOUTH OF UPR MI AND MOISTURE IS SCANT...-SN CHANCE RETAINED AS WEAK TO MODERATE QG FORCING AHEAD OF THE SHRTWV LOBE MOVING BRUSHES UPR MI. SAT NIGHT INTO SUN...ETA/GFS/UKMET BLEND SUGGESTS THAT AS THE SFC TROF PIVOTS THROUGH S OF THE AREA AND NRN ONTARIO HIGH BUILDS SOUTHWARD...CYCLONIC NNE WINDS WILL DEVELOP ACRS LK SUPERIOR WITH FOCUS OF BEST LOW LVL CONV INTO N CNTRL UPR MI. IF MORE FAVORABLE ETA SCENARIO WITH MORE AGGRESSIVE NRLY WINDS DEVELOPS...ADVY LEVEL SNOWFALL AMOUNTS WOULD BE POSSIBLE GIVEN INVERSION HGTS STARTING NEAR 7K-8K FT. EXPECT THE ETA MAY HAVE BETTER HANDLE ON LOW LVL WINDS WITH ITS DEPICTION OF MORE PRONOUNCED GREAT LAKE AGGREGATE TROFFING. MON INTO TUE...GOING FCST OF -SN CHANCES STILL LOOKS ON TRACK WITH DEVELOPING STRONG WAA PATTERN. MDLS TREND HAS BEEN TOWARD KEEPING DEEP COLD AIR MORE ENTRENCHED WITH THICKNESS VALUES SUPPORTING ALL SNOW DURING PERIOD OF MOST FAVORABLE LIFT. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL 11 PM EST THIS EVENING MIZ001-003. LAKE EFFECT SNOW WARNING UNTIL 11 AM EST TODAY MIZ006. && $$ JLB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 1030 AM EST FRI DEC 24 2004 .UPDATE... NO UPDATE NEEDED. 150KT JET ALOFT AND SW FLOW ALOFT WILL CONTINUE TO PRODUCE EXTENSIVE CIRRUS STRATUS DECK ACROSS THE CWA TODAY. THE LOWER STRATUS LAYER ACROSS THE EASTERN HALF OF CWA EAST ASSOCIATED WITH 850 TROUGH AND CONVERGENCE AREA. THE RUC AND MESOETA SHOW THIS FEATURE MOVING VERY LITTLE DURING THE COURSE OF THE DAY...NOT SHIFTING EAST UNTIL AFTER 00Z. LOWER CLOUD BASE WILL HAVE GREATER IMPACT ON TEMPERATURES ACROSS THE EAST... THUS EXPECT MINIMAL SPREAD ACROSS THE CWA THIS AFTERNOON. NORTHERLY WINDS WILL DECENT WIND GUSTS (~17KTS) WILL ADD EXTRA CHILL TO THE AIR. FORECAST HIGHS OF 40 TO 43 LOOK ON TRACK. SEE NO REASON TO UPDATE. && .PREV DISCUSSION (TODAY THROUGH SUNDAY NIGHT)... OVERALL... ALOFT BROAD UPPER TROUGH OVER THE REGION THROUGH THE HOLIDAY WEEKEND WHILE HIGH PRESSURE DOMINATES AT THE SURFACE. LOW LEVELS DRYING OUT. BUT HIGH LEVEL CLOUDS SPREADING UP FROM SOUTHWEST IN RESPONSE SOUTHERN JET AND CUTOFF FROM SOUTHERN TEXAS AND ASSOCIATED SURFACE WAVE SLIDING EAST ALONG THE GULF COAST REGION. THIS TO RESULT IN HIGH LEVEL CLOUDS ACROSS THE CWA TODAY THROUGH EARLY SATURDAY. MOST OF THIS STAY SUPPRESSED TO OUR SOUTH. OTHERWISE BASICALLY A TEMPERATURE FORECAST DURING THIS PERIOD. STRONG CAA CONVECTION TODAY THROUGH SATURDAY NIGHT...WITH SATURDAY NIGHT COLDEST DURING THIS PERIOD. HIGHS TODAY WILL AVERAGE 15-20 DEGREES COLDER THAN YESTERDAY AS HIGHS RANGE FROM MID 60S NORTHWEST TO AROUND 70 SOUTHEAST. HIGH LEVEL CLOUDS COULD RETARD MAXES A BIT TODAY...THUS WILL TWEAK DOWN A FEW DEGREES. SOME MORNING CLOUDS SATURDAY...THEN CLEAR AND COLD FOR SATURDAY/SATURDAY NIGHT. TEMPERATURES BEGIN TO MODERATE ON SUNDAY BUT STILL BELOW SEASONAL NORMS. && .LONG TERM (MONDAY THROUGH WEDNESDAY)... THE NEW WEEK TO START WITH HIGH AMPLITUDE RIDGE BUILDING IN THE CENTRAL CONUS. RIDGE FLATTENS TOWARD MID WEEK RESULTING IN NEARLY ZONAL FLOW AS S/W EAST ALONG NORTHERN TIER CONUS. ALL IN ALL...A DRY WEEK ACROSS THE REGION WITH MODERATING TEMPERATURES..RETURNING CLOSER SEASONAL NORMS. && .AVIATION... COLD FRONT WELL OFFSHORE AS OF 06Z/24 DEC. LOW LEVEL MOISTURE HAD SINCE SCOURED OUT... LEAVING BROKEN CIRRUS ABOVE. SURFACE WINDS WERE GUSTY JUST BEHIND THE FRONT... BUT SINCE SUBSIDED TO LESS THAN 10 KNTS... DUE IN PART TO WEAKNESS IN THE SURFACE PRESSURE FIELD IN THE LEE OF THE MOUNTAINS INTO THE PIEDMONT. THE PRESSURE GRADIENT SHOULD BECOME TIGHTER AFTER 09Z... BUT BY THAT TIME WE MAY BE DECOUPLED FROM WINDS ABOVE THE BOUNDARY LAYER. WILL INCREASE WINDS TO 11-12 KNOTS AROUND SUNRISE WITH BROKEN TO OVERCAST CIRRUS ALL DAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NC...NONE. && $$ UPDATE...BL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 900 PM EST FRI DEC 24 2004 .SHORT TERM /TONIGHT/...CURRENT RADAR LOOP HAS NOT CHANGED MUCH OVER THE PAST HOUR OR TWO...WITH MOST OF THE LIGHT RAINFALL OCCURRING EAST OF HIGHWAY 17 IN SC AND EAST OF I-95 DOWN IN SE GEORGIA. HAVE NOT RECEIVED ANY MORE REPORTS OF SLEET OVER THE PAST FEW HOURS...BUT WOULDNT BE SURPRISED IF SOME SLEET DID FALL WHERE THE RADAR WAS INDICATING GREATER THAN 35 DBZ. LATEST CHS AND JAX SOUNDING SHOW A WARM ATMOSPHERE ABOVE 0 CELSIUS IN THE LOWEST FEW HUNDRED MILLIBARS. THUS LIKELIHOOD OF ADDITIONAL SLEET IS DECREASING RAPIDLY. THERE IS SOME DRY AIR PRESENT IN THE SOUNDING SO SOME COOLING IS POSSIBLE IF EVAPORATION TAKES PLACE. BOTH THE MESOETA AND RUC SHOW THAT THE PRECIP SHOULD CONTINUE TO PUSH OFFSHORE AND STAY THERE OVERNIGHT WITH NO ADDITIONAL DEVELOPMENT. GFS DOES HOWEVER SHOW A BIT MORE MORE RH AND PRECIP OVER SE GA. WILL CONTINUE SLIGHT CHANCE OF IP THROUGH AROUND MIDNIGHT...AND THEN TAPER POP OFF TO AROUND 20 ALONG THE COAST. TEMPS LOOK FINE AND WILL LIKELY LOWER WIND SPEEDS OVER INLAND AREAS BASED ON CURRENT METARS. && .MARINE...WINDS SURGING A BIT AT 41008 AND WILL THEREFORE INCREASE SPEEDS ACROSS THE NEARSHORE GA WATERS. WILL KEEP WITH SCA FOR THE GA OFFSHORE WITH SABSOON TOWERS R2 AND R8 REPORTING SEAS OF 6 TO 7 FT. && .AVIATION...WILL KEEP LOW CLOUDS AROUND MUCH OF THE NIGHT AND INTO EARLY SAT MORNING WITH IMPROVING CONDITIONS LATE MORNING. COULD SEE SOME DECKS DROP BELOW 1KFT ALONG THE COAST BY MORNING. DRY AIR IS WORKING EAST AND CIGS WILL ERODE FOR A TIME...BUT EXPECTING DECKS TO FORM ONCE AGAIN EARLY SAT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY AMZ374. && $$ PY sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 253 PM EST FRI DEC 24 2004 .SHORT TERM... MODELS HAVE BECOME MORE AGGRESSIVE SPREADING PRECIPITATION INTO EASTERN AND SOUTHERN SOUTH CAROLINA...ESPECIALLY SUNDAY. CAN NOT IGNORE POSSIBLE WINTER WEATHER...ALTHOUGH AT THIS TIME...APPEARS TO BE MINOR EVENT. WATER VAPOR SHOWING UPPER TROUGH CENTERED IN THE GREAT LAKES/SOUTHERN CANADA NOW AMPLIFYING...WITH SHORT WAVES MOVING SOUTHEAST ACROSS MIDWEST/OHIO VALLEY. UPPER LOW CUT OFF IN NORTHERN MEXICO MOVING SOUTHEAST. SOUTHERN STREAM MOISTURE SPREADING NORTHEAST FROM WESTERN GULF OF MEXICO ACROSS GULF COASTAL STATES TO CAROLINAS. WEAK SHORT WAVES EMBEDDED IN THIS SOUTHERN STREAM FLOW...WEAK SURFACE LOW PRESSURE OFF THE SOUTH CAROLINA COAST. MODEL SOUNDINGS AND SURFACE OBS INDICATE MOISTURE ABOVE 15000 FT...AND LOTS OF LOW LEVEL MOISTURE IN THE AREA THIS AFTERNOON. DRY AIR IN THE MID LEVELS. WITH SHORT WAVES AND RESULTING UPWARD VERTICAL MOTION...SCT LIGHT PRECIP HAS BEEN FALLING ACROSS EASTERN PORTION OF MIDLANDS...WITH RAIN MIXING WITH SLEET...MODERATE SLEET REPORTED IN BAMBERG EARLIER. SURFACE TEMPS ABOVE FREEZING SO NO PROBLEMS. RADAR INDICATING PRECIP MOVING EAST OF REGION. ETA BUFKIT T-SECTIONS SHOW A RETURN OF MOISTURE LATER THIS EVENING...MAINLY BEFORE MIDNIGHT...WITH MID LEVELS BECOMING MORE MOIST...OMEGA NOTED...LOOKS LIKE ANOTHER WEAK SHORT WAVE...WILL KEEP SLIGHT CHANCE POPS IN THE EASTERN MIDLANDS THIS EVENING WITH A MIX OF LIGHT RAIN AND SLEET...IN THE CAE AREA MAY SEE A FEW FLURRIES WITH TEMPERATURE PROFILE ISOTHERMAL...BUT LESS MOISTURE IN THE LOWER TO MID LEVELS. LOOKS LIKE SOME DRIER AIR MOVES INTO AREA SATURDAY...BUT LOW PRESSURE DEVELOPING IN THE GULF OF MEXICO ALONG BAROCLINIC ZONE. UPPER LOW IN MEXICO WILL MOVE EAST-NORTHEAST ALONG GULF COAST AND ACROSS NORTHERN FLORIDA SUNDAY. MODELS SHOW 500MB VORT ADVECTION AFTER MIDNIGHT SUNDAY IN THE EASTERN MIDLANDS/COASTAL SOUTH CAROLINA. SURFACE LOW MOVES ACROSS CENTRAL/SOUTH FLORIDA THEN OFF THE SOUTH CAROLINA COAST EARLY SUNDAY.UPPER LEVEL FORCING LOOKS GOOD THROUGH SUNDAY MORNING...BUT LOW LEVEL MOISTURE LACKING IN THE CAE AREA...DEEPER MOISTURE IN THE OGB AREA. GFS ISENTROPIC LIFT/850MB WARM AIR ADVECTION STRONGER THAN ETA...ALTHOUGH BOTH MODELS FOCUS ADVECTION MAINLY NEAR THE COAST. SURFACE HIGH PRESSURE CENTERED IN NEW ENGLAND WILL BE BUILDING SOUTH ACROSS CAROLINA SUNDAY NIGHT...MAY SET UP COLD AIR DAMMING...SURFACE TEMPS MAY BE COOLER...THAN CURRENT THINKING. PLAN ON CHANCE POPS AT THIS TIME. EXPECT HEAVIER PRECIP EAST OF MIDLANDS. PARTIAL THICKNESS SCHEMES INDICATES A WINTRY PRECIP MIX...WITH RAIN AND SLEET EAST...AND RAIN AND SNOW WEST AND NORTH IN COOLER AIR. INTERESTING THAT GFS HINTS AT FREEZING RAIN PROBLEM WITH SURFACE BELOW 0C. BY SUNDAY AFTERNOON LOW PRESSURE MOVING NORTHEAST AWAY FROM CAROLINA COAST...GFS A LITTLE SLOWER DRYING OUT MID LEVELS THAN ETA. TEMPERATURE FORECAST THIS PERIOD TRICKY...EXPECT CLOUDS TO HOLD TEMPS UP TONIGHT...COLD ADVECTION SATURDAY...THINK LOW 50S TOO OPTIMISTIC...TEMPS SATURDAY NIGHT DEPENDING ON COLD AIR DAMMING... WENT WITH COOLER MAV GUIDANCE SUNDAY WITH CLOUDINESS AND SOME SCATTERED PRECIP...CONSERVATIVE NUMBERS IN THE LOW 40S AT CAE. SUNDAY NIGHT SHOULD BE QUITE COLD IN THE 20S WITH CLEARING SKIES. .LONG TERM... NO MAJOR CHANGES IN EXTENDED PERIOD WITH UPPER RIDGE IN THE SOUTHEAST SLOWLY BUILDING AND MODERATING TEMPERATURES EACH DAY. NO POPS. && .AVIATION... CIGS 2-3 THOUSAND FEET OVER THE AREA LATE THIS AFTERNOON EXTENDING INTO THE EVENING HOURS UNTIL NEAR 02Z. CAE 88D IS PICKING UP LIGHT PRECIP BETWEEN AGS AND OGB WITH DBZ 25-35. PORBABLY SOME LIGHT SLEET. MUCH OF THE PRECIP IS NOT REACHING THE GROUND AS DRY LAYER 850MB-700MB OR 5-10 THOUSAND FEET COVERS THE AREA. LOWER LAYER IS ABOUT 1 THOUSAND FEET DEEP. RUC/MESOETA TIME SECTIONS ARE BRINGING A QUICK SHOT OF MOISTURE IN DRY LAYER THIS AFTERNOON BUT IT DOESN'T LAST VERY LONG. SOME SLEET MAY REACH THE GROUND BUT EXPECT NO WEATHER PROBLEMS FROM THE PRECIP. LOW LAYERS DRY OUT AFTER 02Z WITH JUST MID AND HIGH LEVEL CLOUDS. NO FOG EXPECT CHRISTMAS MORNING. && .PRELIMINARY POINT TEMPS/POPS... COLUMBIA 32 46 30 43 / 10 10 30 30 AUGUSTA 30 46 31 44 / 10 10 40 40 SUMTER 31 46 30 42 / 10 10 30 30 ORANGEBURG 32 46 31 43 / 20 10 40 40 && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ AWP...SHORT TERM/LONG TERM TTH...AVIATION sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE COLUMBIA SC 1046 AM EST FRI DEC 24 2004 .UPDATE... CAE 88D PICKING UP SOME PRETTY GOOD ECHOES ENTERING THE SOUTHERN PART OF THE CAE CWA. 35-45 DBZ RETURNS FROM BURKE COUNTY,GA WAS CONFIRMED BY THE BURKE CO SHERIFF OFFICE AS SLEET. MODELS SHOW SHALLOW MOISTURE LAYER IN THE LOW LEVELS 2-3 THOUSAND FEET BUT A DRY LAYER FROM 850MB-700MB ABOUT 5-10 THOUSAND FEET. RUC/MESOETA TIME SECTIONS FROM SOUTHERN PART OF CWA INCLUDING BARNWELL AND ORANGEBURG COS INDICATE SOME MOISTENING UP OF DRY LAYER THIS AFTERNOON. WILL UPDATE SOUTHERN ZONES TO GO 30 PERCENT CHANCE LIGHT RAIN AND SLEET FROM BURKE CO, GA NORTHEAST THROUGH CLARENDON CO. WILL ALSO INCLUDE A 20 PERCENT CHANCE OF SLEET CENTRAL MIDLANDS FROM AUGUSTA,GA TO COLUMBIA TO SUMTER. WILL LOWER HIGHS TO THE MID TO UPPER 30S. NO CHANGE TO TONIGHT FORECAST SINCE MODELS JUST HAVE A QUICK SHOT OF LOW LEVEL MOISTURE WHICH IS GONE BY SUNSET. && .PREV DISCUSSION... .SHORT TERM...(FRI-SUN)...LONG WAVE TROUGH OVER THE AREA WILL HOLD IN THROUGH THE WEEKEND AS AN UPPER DISTURBANCE WILL SLIDE TO OUR SOUTH...JUST ABOUT A COUPLE OF HUNDRED MILES NORTH ON THE LOW TRACK AND WE WOULD HAVE A VERY DIFFERENT SITUATION...HOWEVER THE CIRRUS DECK ASSOCIATED WITH THE DISTURBANCE WILL KEEP SKIES MOSTLY CLOUDY TODAY AND TONIGHT WITH SOME MINOR ADJUSTMENTS TO TEMPS MADE FOR EACH PERIOD. WINDS WILL BE PICKING UP A BIT SAT NIGHT AS THE LOW PASSE BY, HAVE BUMPED UP MINS BIT SAT PM DUE TO WINDS. THINGS CLEAR OUT SUN WITH MODERATING TEMPS. && .LONG TERM...(MON-FRI)...ZONAL FLOW SETS UP WITH UPPER RIDGE BUILDING IN FROM THE WEST SFC HIGH WILL NOSE DOWN THE EAST COAST AND KEEP US DRY FOR THE WEEK WITH MODERATING TEMPS APPROACHING NEAR NORMAL BY MID WEEK AND ABOVE NORMAL BY THE END OF THE WEEK. && .AVIATION... VFR CONDITIONS SHOULD CONTINUE THROUGH THE PERIOD. EXPECT NORTHEAST WINDS NEAR 10 KNOTS BEHIND A REINFORCING COLD FRONT TODAY WITH WINDS DIMINISHING TO NEAR 5 KNOTS AROUND SUNSET. THERE MAY BE SOME COLD ADVECTION STRATOCUMULUS BUT IT/S PROBABLY TOO DRY FOR A MVFR CEILING. UPPER-LEVEL CLOUDINESS SHOULD BE ON THE INCREASE ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF THE H25 JET. && .PRELIMINARY POINT TEMPS/POPS... COLUMBIA 44 30 48 27 / 0 0 0 10 AUGUSTA 43 28 49 28 / 0 0 0 10 SUMTER 44 29 48 27 / 0 0 0 10 ORANGEBURG 44 30 48 28 / 0 0 0 10 && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 07/19 sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1045 AM EST FRI DEC 24 2004 .UPDATE SHORT TERM...WILL GO AHEAD AND MENTION SLIGHT CHANCE OF MIX PCPN ENTIRE CWA THIS AFTN. A COUPLE OF REPORTS HAVE ALREADY COME IN MENTIONING PCPN IN SC COUNTIES. STILL NO ACCUMULATIONS EXPECTED. PREVIOUS DISCURRION .SHORT TERM /TODAY THROUGH TONIGHT/...LOOKING AT SATELLITE...RADARS OVER THE SE AND SFC OBS...SPOTTY LIGHT PCPN IS HITTING THE GROUND THIS MORNING ALONG THE GULF COAST STATES AND EVEN INTO SW GA. MOISTURE PRESENTLY LIMITED WITH DEWPTS IN THE LOW TO MID 30S AND MAY DROP A FEW MORE DEGREES OVER SC COUNTIES. HOWEVER WITH MOISTURE ADVECTION INTO SW GA THIS MORNING...EXPECT ENUF MOISTURE TO MOVE INTO GA PTN OF CWA TO SEE PCPN THIS AFTN AND CONTINUE INTO SC COUNTIES THIS EVENING. COULD SEE A MIXTURE OF PCPN SO WILL START IT OUT AS RAIN PSBLY MIXED WITH SLEET WITH NO ACCUMULATIONS EXPECTED. && .LAKE WINDS...PINEVILLE OBS HAVE COME IN AT 10-15 KT THE PAST COUPLE OF HRS. BEST PRES GRAD LOOKS TO REMAIN OFFSHORE WHILE HIGH PRES BUILDS INLAND SO WILL CONTINUE TO LOOK FOR DECRG SPEEDS BUT NOT QUITE AS MUCH AS CURRENT FCST HAS. WILL DECRS WINDS TO 15 KT TDA THEN BLEND IT BETTER FOR TNGT. && .MARINE...WINDS RATHER STUBBORN TO SETTLE DOWN TDA AS PER BUOYS AND PILOT BOAT REPORTS. BUOYS...SHORELINE OBS...AND CHS PILOT BOAT ALL REPORTING 15-20 KT WIND SPEEDS. CULPRIT IS A FAIRLY TIGHT SFC PRES GRAD OVER THE WATERS BETWEEN STALLED FRONT WELL OFFSHORE AND BUILDING HIGH INLAND. BOTH RUC AND M-ETA SHOW PRES GRAD TO REMAIN OVER THE WATERS THRU THE DAY WITH WINDS NOT DROPPING OFF AS PREV EXPECTED. WILL ADJUST SPEEDS TDA TO MAINTAIN UPPER RANGES OF WIND SPEEDS THRU THIS AFTN AND ALSO SLIGHTLY INCRS WINDS TNGT AS SPEEDS DO NOT LOOK TO DROP OFF MUCH TNGT...PARTICULARLY DURG AN ANTICIPATED OVRNGT SURGE. WAVES LOOK ON TRACK SO NO CHANGES NEEDED THERE. . && .AVIATION...MVFR CIGS WILL CONTINUE TO PLAGUE KCHS THRU AT LEAST MIDDAY AS LLVL MOISTURE SHIFTS OFF TO THE NE. WILL MAINTAIN TEMPO CIGS AS LOW AS 1500FT UNDER PREVAILING HIGH BKN SKIES. VIS SAT PIX SHOWING BREAKS IN THE CLOUDS ARND KSAV...SO SCT/BKN HIGH CIGS LOOK TO SUFFICE. MAY NEED TO AMD FOR INCRD WIND SPEEDS THIS MRNG...ESP KCHS...AS BOTH SITES SHOWING WIND SPEEDS A BIT ABV GOING VALUES. LWR LVLS STILL LOOK TOO DRY TO INCLUDE PRECIP SO WILL MAINTAIN DRY TAFS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY AMZ374. && $$ JH/JPC sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 951 AM EST FRI DEC 24 2004 .SHORT TERM /TODAY THROUGH TONIGHT/...LOOKING AT SATELLITE...RADARS OVER THE SE AND SFC OBS...SPOTTY LIGHT PCPN IS HITTING THE GROUND THIS MORNING ALONG THE GULF COAST STATES AND EVEN INTO SW GA. MOISTURE PRESENTLY LIMITED WITH DEWPTS IN THE LOW TO MID 30S AND MAY DROP A FEW MORE DEGREES OVER SC COUNTIES. HOWEVER WITH MOISTURE ADVECTION INTO SW GA THIS MORNING...EXPECT ENUF MOISTURE TO MOVE INTO GA PTN OF CWA TO SEE PCPN THIS AFTN AND CONTINUE INTO SC COUNTIES THIS EVENING. COULD SEE A MIXTURE OF PCPN SO WILL START IT OUT AS RAIN PSBLY MIXED WITH SLEET WITH NO ACCUMULATIONS EXPECTED. && .LAKE WINDS...PINEVILLE OBS HAVE COME IN AT 10-15 KT THE PAST COUPLE OF HRS. BEST PRES GRAD LOOKS TO REMAIN OFFSHORE WHILE HIGH PRES BUILDS INLAND SO WILL CONTINUE TO LOOK FOR DECRG SPEEDS BUT NOT QUITE AS MUCH AS CURRENT FCST HAS. WILL DECRS WINDS TO 15 KT TDA THEN BLEND IT BETTER FOR TNGT. && .MARINE...WINDS RATHER STUBBORN TO SETTLE DOWN TDA AS PER BUOYS AND PILOT BOAT REPORTS. BUOYS...SHORELINE OBS...AND CHS PILOT BOAT ALL REPORTING 15-20 KT WIND SPEEDS. CULPRIT IS A FAIRLY TIGHT SFC PRES GRAD OVER THE WATERS BETWEEN STALLED FRONT WELL OFFSHORE AND BUILDING HIGH INLAND. BOTH RUC AND M-ETA SHOW PRES GRAD TO REMAIN OVER THE WATERS THRU THE DAY WITH WINDS NOT DROPPING OFF AS PREV EXPECTED. WILL ADJUST SPEEDS TDA TO MAINTAIN UPPER RANGES OF WIND SPEEDS THRU THIS AFTN AND ALSO SLIGHTLY INCRS WINDS TNGT AS SPEEDS DO NOT LOOK TO DROP OFF MUCH TNGT...PARTICULARLY DURG AN ANTICIPATED OVRNGT SURGE. WAVES LOOK ON TRACK SO NO CHANGES NEEDED THERE. . && .AVIATION...MVFR CIGS WILL CONTINUE TO PLAGUE KCHS THRU AT LEAST MIDDAY AS LLVL MOISTURE SHIFTS OFF TO THE NE. WILL MAINTAIN TEMPO CIGS AS LOW AS 1500FT UNDER PREVAILING HIGH BKN SKIES. VIS SAT PIX SHOWING BREAKS IN THE CLOUDS ARND KSAV...SO SCT/BKN HIGH CIGS LOOK TO SUFFICE. MAY NEED TO AMD FOR INCRD WIND SPEEDS THIS MRNG...ESP KCHS...AS BOTH SITES SHOWING WIND SPEEDS A BIT ABV GOING VALUES. LWR LVLS STILL LOOK TOO DRY TO INCLUDE PRECIP SO WILL MAINTAIN DRY TAFS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY AMZ374. && $$ JH/JPC sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1041 AM EST FRI DEC 24 2004 DO NOT ANTICIPATE MUCH (IF ANY) CHANGE TO THE AFTERNOON FORECASTS. COLDER AIR CONTINUES TO GRADUALLY FILTER IN...MAINLY AT LOW LEVELS AT THIS POINT HOWEVER GIVEN THE STRONG LOW LEVEL INVERSION AND BACKING WIND PROFILE ABOVE 850 MB (FROM 12Z KWAL SOUNDING). MEANWHILE...EXTENSIVE WARM CONVEYOR BELT MOISTENING CONTINUES ALOFT PER THE STLT LOOPS...WITH THE MOISTURE CONNECTION (OVERRUNNING THE BROAD ARCTIC AIRMASS) EXTENDING THROUGH MEXICO AND SOUTH OF BAJA. CLOUDS ARE GENERALLY AOA 12 KFT N OF THE VA/NC BORDER...THOUGH SOME LOWER CEILINGS (AOB 6 KFT) WERE NOTED ACROSS SERN VA/NERN NC. THINK THE INCREASING OVER-WATER INSTBY DOWNWIND FROM CHES BAY AND ATLANTIC COASTAL WATERS IS AT LEAST IN SOME WAY CONTRIBUTING TO THE DEVELOPMENT OF THESE LOWER CLOUDS. WILL LIKELY WORK A MORE PESSIMISTIC SKY FORECAST FOR THE SRN ZONES...GIVEN THE DEEPER MOISTURE. FOR THE REST OF THE REGION (N AND W OF SERN VA)...WILL CALL IT PARTLY SUNNY. DO NOT LOOK FOR ANY PRECIP REACHING THE GROUND THIS AFTERNOON...GIVEN THE DRY NORTHERLY ISALLOBARIC FLOW AT LOW LEVELS. *PERHAPS* A STRAY SPRINKLE OR FLURRY OVER NERN NC...THOUGH EVEN IN THIS REGION RUC MODEL SOUNDING SHOW A DEEP LAYER OF DRY AIR (BTWN 850-650 MB)...GREATER THAN 5 KFT IN DEPTH AND AS SUCH WOULD PRECLUDE ICE SEEDING INTO THE LOWER MOIST LAYER. MARINE FORECAST...MINIMAL CHANGES MADE AS SMALL CRAFT ADVISORIES CONTINUE AREAWIDE. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FOR ALL MARINE ZONES. && HURLEY PREVIOUS DISCUSSION BELOW... --------------------------------------------------------------------- .SYNOPSIS/OVERVIEW... AFTER THE WELL ABV NORM TEMPS OF THE PAST 2 DAYS...BIG CHANGES ON THE WAY AS A MUCH COLDER AIRMASS OVERTAKES THE MID ATLC REGION TODAY. SPLIT FLOW REGIME OVR EASTERN STATES KEEPS PCPN CHCS AT A MINIMUM THRU WEEKEND AND INTO EARLY NEXT WEEK. TEMPS REBOUND TO NEAR SEASONAL NORMS EARLY NEXT WEEK THEN BACK ABV NORM BY MIDWEEK AS UPR RDGG GRADUALLY RETURNS TO MID ATLC REGION. && .SHORT TERM (TODAY THROUGH SATURDAY NIGHT)... SHALLOW COLD DOME WILL BUILD OVR REGION TODAY. ONLY A SMALL RISE IN TEMPS EXPECTED (5-10 DEGS) AS READINGS START OUT MOSTLY IN THE 30S (EXCEPT L40S FAR SE). QUITE BRISK ESP CSTL AREAS THIS MORN THEN WIND GRADUALLY DIMINISHES AS STRONG LOW LVL CAA SURGE SUBSIDES THIS AFTN. ONLY LIMITED SUN EXPECTED TODAY AS WELL WITH LAYERED CLOUDS...LOW CLOUDS STUCK UNDER INVERSION MNLY OVR EASTERN AREAS AND MID/HIGH CLOUDS WELL IN ADV OF SOUTHERN STREAM SYS. SFC WAVE DEVELOPS ON OLD FRONT OVR GULF STREAM TNGT BUT SHUD RMN FAR ENUF OFFSHORE TO KEEP ANY ASSOCD PCPN SE OF FORECAST AREA. CLOUDS LIKELY LINGER THRU MUCH OF OVRNGT ESP OVR SE AREAS BEFORE BROAD UPR TROF PUSHES THRU SAT MORN. QUITE COLD TNGT ESP INLAND AS 8H TEMPS CONT TO DROP BUT LINGERING CLOUDS AND SFC MIXING PREVENT FULL TEMP DROPOFF POTENTIAL. STRONG SOUTHERN STREAM SYS MOVES ACRS GULF COAST SAT THEN OFF FLA/GA COAST SAT NIGHT. MID/UPR CONVERGENCE OVR MID ATLC REGION SHUD SUPRESS SYS FAR ENUF SOUTH TO HAVE LTL EFFECT ON FORECAST AREA. CONT COLD THO WITH LOW LVL THICKNESS INDICATING HIGHS ONLY IN THE 30S FOR MOST ON CHRISTMAS DAY. WILL ALSO SEE TIGHTENING PGRAD/INCRSG WINDS AGN ALONG COAST WITH SYS OFF SE COAST AND STRONG HIGH TO NORTH. COLD AGAIN SAT NIGHT WITH MANY LOWS IN THE TEENS INLAND/20S CST. && .LONG TERM (SUNDAY THROUGH THURSDAY)... SLOW WARMING TREND BEGINS SUNDAY AS UPR RDG GRADUALLY BUILDS OVR EASTERN STATES. NORTHERN STREAM SYS RIDES THRU NRN MID ATLC/NE STATES TUE NIGHT BUT LENDS LTL UPR SUPPORT OR DEEP MOISTURE FOR ANY PCPN OVR CNTRL MID ATLC REGION. SHUD FINALLY SEE BETTER RETURN FLOW SET UP BY MIDWEEK AND A RETURN TO ABV NORM TEMPS. && .AVIATION...SOME LOW CLOUDS REMAIN TODAY BUT EXPECT CIGS ABV VFR CRITERIA NEXT 24 HOURS. && .MARINE...SMALL CRAFT ADV ALL AREAS TODAY. PGRAD WILL RMN STRONG BTWN SE COASTL SYS AND STRONG HIGH TO NORTH THRU MUCH OF WEEKEND. LONG FETCH SHUD KEEP SEAS UP AS WELL. && $$ SHORT TERM/LONG TERM...CULLEN AVIATION/MARINE...BROWN va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 225 PM CST FRI DEC 24 2004 .SYNOPSIS...MORNING ANALYSIS SHOWS A 500 MB PATTERN THAT IS PROGRESSING. THIS IS MOVING THE TROUGH THAT HAS BROUGHT THE ARCTIC AIR INTO THE REGION OFF TO THE EAST. AT THE SURFACE...A RIDGE OF HIGH PRESSURE EXTENDED ALONG THE WESTERN GREAT LAKES. SOUTHWESTERLY FLOW ASSOCIATED WITH WARM ADVECTION WAS LOCATION OVER THE PLAINS AND WESTERN PORTION OF THE UPPER MISSISSIPPI RIVER VALLEY. THIS HAS CAUSED TEMPERATURES TO RISE QUICKLY THIS AFTERNOON ACROSS THAT REGION...WARMING FASTER THAN PREVIOUSLY EXPECTED. LOW PRESSURE WAS CENTERED OVER CENTRAL SOUTH DAKOTA. KRC && .SHORT TERM...CHRISTMAS EVE AND CHRISTMAS DAY MAIN FORECAST PROBLEMS...WILL THE NEXT SYSTEM PRODUCE ENOUGH FORCING TO PRODUCE PRECIPITATION DURING THE PERIOD? AND...TEMPERATURES. SURFACE LOW PRESSURE MOVES SOUTHEAST TONIGHT AND SATURDAY. BY SATURDAY EVENING...IT MOVES INTO NORTHERN ILLINOIS. SOME WEAK FORCING REMAINS ASSOCIATED WITH THE WARM FRONT AS IT NEARS THE FORECAST AREA. THE ETA/GFS/RUC RUNS ARE SIMILAR WITH TIMING AND THE FORCING SIGNALS. THESE FORCING SIGNALS ARE NET ADIABATIC ASCENT ON THE 280K SURFACE AND SOME WEAK 700-500 MB QG CONVERGENCE. THESE MAY BE ENOUGH TO PRODUCE PRECIPITATION. HOWEVER...THE DEWPOINT DEPRESSIONS ARE BETWEEN 10 AND 20 DEGREES UPSTREAM. THEREFORE...WEAK FORCING WILL LIKELY NOT OVERCOME THE DRY AIR UNLESS IT IS PROLONGED. THEREFORE...WILL CONTINUE A CHANCE OF SNOW. REGARDING TEMPERATURES...WARM ADVECTION IN THE BOUNDARY LAYER WILL CONTINUE TEMPERATURE RISES. HOWEVER...THE GRADIENT IS NOT STRONG ENOUGH TO MITIGATE DECOUPLING. THEREFORE...WILL GO FOR A LOW AROUND 3Z. KRC SATURDAY NIGHT THROUGH MONDAY. 12Z 24DEC04 GFS AND ETA IN FAIRLY GOOD AGREEMENT THROUGH THE PERIOD. DIFFERENCES ARISE IN QPF PRODUCTION GIVEN WARM AIR ADVECTION AND ISENTROPIC LIFT ON MONDAY. GIVEN THE DYNAMICS...A BLEND APPROACH SEEMS REASONABLE WITH SMALL CHANCE WORDING. WAVE OF LOW PRESSURE EXITS EAST OF THE AREA BY SATURDAY EVENING...TAKING PRECIPITATION WITH IT. PARTIAL CLEARING LATE WITH COLD AIR ADVECTION WILL ALLOW TEMPERATURES TO DROP INTO THE SINGLE DIGITS BY EARLY SUNDAY MORNING. SUNDAY WILL SEE AN INCREASE IN CLOUDS AS THE DAY WEARS ON. THIS IS IN RESPONSE TO HIGH MOVING OFF TO THE EAST AND WARM AIR ADVECTION/ISENTROPIC LIFT IN ADVANCE OF NEXT CLIPPER SYSTEM. INCREASED ISENTROPIC LIFT (280K SURFACE) ACROSS THE AREA WILL LEAD TO FURTHER SATURATION AND A SMALL CHANCE OF -SN ACROSS NORTHWEST HALF OF FORECAST AREA SUNDAY NIGHT. MAIN LIFT/FORCING SHIFTS INTO NORTHERN WI ON MONDAY WITH FURTHER WARMING ACROSS OUR AREA. WILL CONTINUE A SMALL CHANCE OF -SN...MAINLY NORTH OF A LINE FROM ROCHESTER TO BLACK RIVER FALLS. DAS .LONG TERM...MONDAY NIGHT THROUGH FRIDAY GFS AND ECMWF IN GOOD AGREEMENT WITH DEEPENING UPPER TROUGH OFF THE WEST COAST THROUGH THE PERIOD. THIS IN TURN WILL CAUSE RIDGING OVER THE CENTRAL CONUS FOR A WARMING TREND ACROSS THE REGION. SURFACE HIGH MOVES EAST OF THE AREA MONDAY NIGHT INTO TUESDAY. RETURN FLOW ON BACKSIDE OF THE HIGH AND IN ADVANCE OF ROCKIES LOW WILL START PULLING GULF MOISTURE NORTHWARD INTO THE AREA. FAIRLY GOOD AMOUNT OF MOISTURE/ISENTROPIC LIFT INDICATED ACROSS THE AREA FOR AT LEAST A MENTION OF SNOW MONDAY NIGHT AND A MIX OF RAIN/SNOW ON TUESDAY. NEXT MAJOR WEATHER-MAKER WILL BE LOW MOVING NORTHEAST OUT OF THE ROCKIES THURSDAY NIGHT AND ACROSS THE UPPER MIDWEST ON FRIDAY. WITH MORE NORTHWARD TRACK OF THIS LOW...BUMPED TEMPERATURE UP A TAD. RIGHT NOW...IT APPEARS ENOUGH WARM AIR WILL GET MIXED INTO THE SYSTEM OVER OUR AREA FOR A RAIN/SNOW MIX. && .ARX WATCHES/WARNINGS/ADVISORIES... .WI...NONE. .MN...NONE. .IA...NONE. && $$ DAS wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 338 AM CST SAT DEC 25 2004 .SHORT TERM... TODAY THROUGH MONDAY NIGHT OF MAIN CONCERN THIS EARLY CHRISTMAS MORNING ARE HIGH TEMPERATURES TODAY AND MINIMUMS TONIGHT. THE LATEST RUC80 MODEL IS THE PREFERRED MODEL FOR MY CW AREA TODAY. THE LATEST SATELLITE IMAGERY LOOPS REVEAL A FEW HIGH CLOUDS MOVING ACROSS SOUTHERN ARKANSAS AND MOSTLY CLEAR SKIES OVER THE REMAINDER OF THE NATURAL STATE AS HIGH PRESSURE PREVAILS. THE RESIDUAL SNOW COVER AND PATCHY ICE WILL CONTINUE TO PLAY A ROLE IN THE TEMPERATURE TRENDS TODAY AND TONIGHT. THE LATEST GFS MOS GUIDANCE IS HOWEVER SHOWING TEMPERATURES ABOUT 4 DEGREES HIGHER THAN EARLIER EXPECTED FOR TODAY...TONIGHT AND TOMORROW SO WILL RAISE THE ON-GOING FORECAST TO BE MORE IN LINE WITH THE NEW THINKING. LITTLE OR NO PRECIPITATION IS EXPECTED TODAY THROUGH MONDAY NIGHT. (38) && .LONG TERM...TUESDAY THROUGH FRIDAY RIDGE OF HIGH PRESSURE AT THE SURFACE WILL CONTINUE ACROSS THE AREA WITH A BIG UPPER RIDGE OVER THE AREA WHICH SLOWLY MOVES TO THE EAST AND SETS UP OVER THE SOUTHEASTERN U.S. BY THE END OF NEXT WEEK...ALSO THE END OF THE YEAR. UPPER TROF WILL SET UP OFF THE WEST COAST WITH A SHORT WAVE OR TWO TRYING TO MOVE INTO THE CENTRAL PART OF THE COUNTRY BUT GETTING SHUNTED OFF TO THE NORTHEAST BY THE UPPER RIDGE IN THE SOUTHEAST. THIS WILL LEAD TO A PERIOD OF MILDER THAN NORMAL WEATHER WITH ALMOST UNSEASONABLY WARM MAXES INTO THE UPPER 50S AND 60S BY THE LATTER PART OF THE WEEK WITH LOWS MOSTLY IN THE 40S. THE HIGH PRESSURE IN THE AREA AT MID WEEK SHOULD PRECLUDE ANY CHANCE OF RAIN THROUGH WEDNESDAY NIGHT. THE FIRST SHORT WAVE FROM THE WEST MAY GET CLOSE ENOUGH BY THURSDAY TO INDUCE A GOOD ENOUGH MOISTURE RETURN FOR SOME CHANCE OF RAIN AND WILL GO WITH SMALL POPS FOR THEN. GFS INDICATES A FRONT GETTING CLOSE TO THE AREA BY FRIDAY SO WILL GO WITH A CHANCE OF SHOWERS AND THUNDERSTORMS FOR THEN. FRONT MAY STALL AND/OR WASH OUT OVER THE AREA WITH MOISTURE AXIS REMAINING ACROSS THE CWA FOR A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS BUT THIS IS BEYOND THE TIME RANGE OF THIS FORECAST. (29) && .PRELIMINARY POINT TEMPS/POPS... LITTLE ROCK AR 37 22 46 26 / 0 0 0 0 HARRISON AR 39 25 48 28 / 0 0 0 0 HOT SPRINGS AR 39 24 48 26 / 0 0 0 0 PINE BLUFF AR 38 24 48 27 / 0 0 0 0 MOUNTAIN HOME AR 36 25 43 27 / 0 0 0 0 MONTICELLO AR 40 25 50 29 / 0 0 0 0 SEARCY AR 35 21 43 25 / 0 0 0 0 MOUNT IDA AR 41 23 48 25 / 0 0 0 0 RUSSELLVILLE AR 38 20 44 24 / 0 0 0 0 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 38/29 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 407 AM EST SAT DEC 25 2004 .DISCUSSION... MAIN FORECAST CONCERN IS LAKE EFFECT SNOW THROUGH TONIGHT. CURRENT WEATHER...09Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A BROAD TROUGH OVER SE CANADA...A RIDGE MOVING INTO THE WESTERN HIGH PLAINS AND A TROUGH DROPPING DOWN THE BRITISH COLUMBIA COAST. SHRTWVS OF INTEREST TO THIS FORECAST WERE OVER WESTERN ONTARIO...ALONG THE CENTRAL DAKOTAS AND OVER SOUTHERN SASKATCHEWAN. AT THE SURFACE...A HIGH PRESSURE RIDGE EXTENDED FROM JAMES BAY TO OHIO...WHICH WITH CLEAR SKIES PROVIDED VERY COLD TEMPERATURES LAST EVENING. AT THE OFFICE...TEMPERATURES HAVE FALLEN TO -24F...BREAKING THE RECORD DAILY LOW FOR CHRISTMAS DAY. TO THE WEST...A LOW PRESSURE TROUGH EXTENDED FROM ALBERTA TO NORTH DAKOTA...WITH A WARM FRONT SOUTHEAST TO THE LA CROSSE AREA. REGIONAL RADARS AND SURFACE OBSERVATIONS HAVE SHOWN SNOW DEVELOPING AHEAD OF THIS TROUGH/WARM FRONT OVER SOUTHERN MN. 00Z MPX SOUNDING SHOWED A NEARLY MOIST TROPOSPHERE EXCEPT FOR A LAYER BETWEEN 750 AND 850MB WHERE DEWPOINT DEPRESSIONS WERE 10-15C. 800-700MB 2-D FRONTOGENESIS ALSO LINED UP WELL WITH WHERE THE SNOW IS. LAKE EFFECT CONTINUES ON LAKES SUPERIOR AND MICHIGAN WITH DELTA-T\S AROUND 26C. LATEST RADAR IMAGERY IS ALSO SHOWING THE DEVELOPMENT OF A DOMINANT BAND OVER NORTHERN LAKE MICHIGAN. MODEL PREFERENCES...THROUGH SUNDAY HAVE FOLLOWED THE ETA AS THERE ARE VERY FEW DIFFERENCES BETWEEN THE MODELS. AFTERWARDS...THE GFS AND UKMET CONTINUE TO HOLD MORE OF AN EASTERN TROUGH IN THAN THE ETA. PER PMDHMD HAVE FOLLOWED THE GFS/UKMET SOLUTION. NEW 00Z ECMWF ALSO SUPPORTS THE GFS/UKMET. TODAY...SHRTWV ALONG THE CENTRAL DAKOTAS IS PROGGED TO MOVE AROUND THE BROAD TROUGH IN EASTERN CANADA WHILE THE SHRTWV OVER WESTERN ONTARIO MOVES TO NORTHERN LAKE SUPERIOR BY 00Z. LACK OF ANY UPPER JET SUPPORT AND DPVA FROM SHRTWVS MEANS THAT ANY SNOWFALL TRYING TO HEAD TOWARDS UPPER MICHIGAN WILL ONLY BE AIDED BY WARM ADVECTION. ISENTROPIC LIFT IS NOT THAT IMPRESSIVE EITHER WITH ONLY THE 280-285K SURFACES SHOWING SOME WEAK LIFT...PRIMARILY OVER THE WISCONSIN BORDER COUNTIES. 800-700MB 2-D FRONTOGENESIS WEAKENS THROUGH THE DAY TOO. SO ANY SNOWFALL TODAY SHOULD NOT BE THAT SIGNIFICANT. IN FACT...THE ETA QPF FIELD ONLY SHOWS A FEW HUNDREDTHS OVER THE BORDER COUNTIES THIS MORNING. WHAT DOES LOOK TO BE MORE SIGNIFICANT IS THE DEVELOPMENT OF A DOMINANT BAND ON LAKE MICHIGAN THIS MORNING WHICH MOVES INTO SCHOOLCRAFT AND LUCE COUNTIES. LOCAL WORKSTATION ETA THEN HAS THE BAND MOVING INTO WESTERN MACKINAC AND LUCE COUNTIES DURING THE AFTERNOON. ETA12 IS SIMILAR. A 3000 FT DEEP LAYER OF SNOWGROWTH COMBINED WITH THE DOMINANT BAND APPEARANCE WILL PROBABLY RESULT IN INTENSE SNOWFALL RATES. QPF FROM THE WORKSTATION SHOWS ABOUT 0.2 INCHES QPF BETWEEN 14Z AND 18Z WITH THIS BAND. A TOTAL QPF AMOUNT OF 0.6 INCHES IS PROGGED FOR NEWBERRY FROM THE WORKSTATION. FIGURE A 15:1 TO 20:1 SNOWFALL RATIO WILL PROBABLY HOLD FOR THIS BAND. WITH THE INTENSE RATES...HAVE DECIDED TO HOIST A LAKE EFFECT SNOW ADVISORY. AS SOUTHWEST WINDS DEVELOP...TEMPERATURES SHOULD SHOOT UP NICELY...ALBEIT REMAINING ON THE COLD SIDE WITH HIGHS FORECAST IN THE LOW TEENS. TONIGHT...SHRTWV TROUGH OVER NORTHERN LAKE SUPERIOR DROPS SOUTH INTO THE U.P. BY 12Z. DPVA WITH THE SHRTWV...COMBINED WITH LATENT HEATING FROM SUPERIOR...WILL RESULT IN A BAND OF SNOW MOVING SOUTH DOWN THE LAKE THROUGH THE NIGHT. WINDS TURNING TO THE NORTH BEHIND THE SHRTWV AND 850MB TEMPS IN THE -15C TO -20C WILL HELP FOCUS SOME LAKE EFFECT BANDS INTO FAR WESTERN AND NORTH CENTRAL UPPER MICHIGAN...IN PARTICULAR FROM NEGAUNEE TO MUNISING AND FROM IRONWOOD TO ONTONAGON. GIVEN THAT THE 950MB CONVERGENCE NEVER SEEMS TO STAY FOCUSED OUTSIDE OF THE BAND MOVING THROUGH...WILL HOLD OFF ON ANY ADVISORY FOR THE MOMENT. HOWEVER...DO BELIEVE THAT THERE WILL BE SOME DECENT SNOWFALL RATES WITH THE BAND MOVING THROUGH. WARMER NIGHT EXPECTED THAN TONIGHT WITH CLOUD COVER PREVENTING THE GREAT RADIATIONAL COOLING THAT WAS EXPERIENCED. WE SHOULD STILL HAVE LOWS DOWN NEAR THE ZERO MARK AWAY FROM THE LAKES THOUGH. SUNDAY...SHRTWV TROUGH CONTINUES TO PUSH SOUTH WHILE REALLY DRY AIR COMES IN BEHIND IT. RH OVER NW ONTARIO FROM 900-500MB IS 20 PERCENT OR BELOW AT 12Z...AND THIS MOVES ACROSS LAKE SUPERIOR. ALTHOUGH 850MB TEMPERATURES ARE AROUND -20C...THIS AMOUNT OF DRY AIR WILL REALLY SHUT DOWN THE LAKE EFFECT. IN FACT...THE ETA HAS ALL OF THE LAKE EFFECT SHUTTING OFF IN THE MORNING OVER THE WEST. AM RELUCTANT AT THE MOMENT TO SHUT OFF THE LAKE EFFECT GIVEN THAT THE WORKSTATION ETA KEEPS IT GOING INTO THE AFTERNOON...BUT LATER SHIFTS MAY NEED TO LOOK AT THIS AGAIN. THE WORKSTATION ETA ALSO SHOWS A MESO LOW NEAR CARIBOU ISLAND AT 12Z HEADING TOWARDS MARQUETTE COUNTY...AND CANNOT RULE IT OUT GIVEN THE PERW. THIS TROUGH PRODUCES A BAND OF WARM AIR ADVECTION SNOWFALL WHICH MOVES INTO THE WEST HALF OF THE U.P. DURING THE MORNING AND THEN CONTINUES ONWARDS INTO LOWER MICHIGAN BY THE EVENING. IN ADDITION...SW WINDS AND 850MB TEMPS OF -12C OVER LAKE MICHIGAN MAY PROVIDE SOME ENHANCEMENT TO THE SNOW OVER SCHOOLCRAFT AND LUCE COUNTIES. WITH THE RETURN FLOW AND WARMER 850MB TEMPS...WILL BE A WARMER DAY THAN WHAT HAS BEEN SEEN AS OF LATE. HAVE TRIMMED TEMPS A FEW DEGREES THOUGH GIVEN THE CLOUD COVER AND SNOWFALL. MONDAY NIGHT INTO TUESDAY...WITH A FEW OTHER HARD TO TIME SHRTWVS MOVING THROUGH THE NORTHWEST FLOW...AM RELUCTANT TO CHANGE MUCH OF THE FORECAST. WILL LEAVE THE 30 PERCENT CHANCE OF -SN IN FOR MON NIGHT...THOUGH LOOKING AT THE GFS THIS PROBABLY COULD BE REMOVED. UNCERTAINTY LEAVES ME KEEPING IT IN. MAIN THING TO NOTE IS THAT TEMPERATURES WILL CONTINUE TO BE WARMER AS 850MB TEMPS CLIMB TO -7 TO -9C BY 18Z TUE. EXTENDED...GIVEN THE CONCERN WITH THE FIRST FEW PERIODS...NO CHANGES HERE. SHOULD NOTE THAT THE GFS IS STARTING TO LOOK A LITTLE MORE LIKE RAIN FOR THURSDAY INTO FRIDAY AS 850MB TEMPS SHOOT UP TO +6C. NEW YEARS EVE MAY END UP BEING A MILD DAY IF THE 00Z RUN PANS OUT AS DRIER SW FLOW MOVES IN AND 850MB TEMPS REMAIN AROUND 0C. 12Z ECMWF IS SIMILAR. MORE INFO ABOUT THIS IN THE AFTERNOON AFD...BUT ALL SIGNS POINT TO A DEFINITE WARM UP FOR THE EASTERN 2/3 OF THE COUNTRY FOR THURSDAY INTO FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 11 PM EST MIZ007-014-085. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 910 AM EST SAT DEC 25 2004 .SHORT TERM (TODAY THROUGH TONIGHT)... WILL UPDATE TO ADD SCATTERED SNOW SHOWERS TO THE MOUNTAINS. GETTING A FEW REPORTS OF SNOW SHOWERS THERE THIS MORNING...WITH VISIBLE SATELLITE SHOWING FAIRLY EXTENSIVE CLOUD COVER OVER THE MOUNTAINS. A SHORTWAVE PASSING TO THE NORTH AND A 15 KT 925 MB FLOW IS LIKELY THE CAUSE OF THESE SNOW SHOWERS. EXPECT AN GRADUAL DIMINISHING TREND THIS AFTERNOON...AS 925 MB WINDS DIMINISH AND AS THE SHORTWAVE MOVES BY. WILL CONTINUE MENTION OF SNOW SHOWERS OVER THE WATERS...WITH FLURRIES STILL POSSIBLE ALONG THE COAST THIS AFTERNOON AS 925 MB WINDS BECOME ONSHORE (SURFACE WINDS WILL STAY OFFSHORE UNTIL TONIGHT). TEMPERATURES AND WINDS SEEM ON TRACK...WITH NO OTHER CHANGES PLANNED. && .LONG TERM (SUNDAY THROUGH FRIDAY)...STILL SOME QUESTION ABOUT SUNDAY INTO MONDAY EVENT. FOR NOW WILL CONTINUE LIKELY POPS LATER SUNDAY AND SUNDAY NIGHT WITH CHANCE FOR MONDAY. NO CHANGES TO CURRENT FORECAST THEREAFTER. && .AVIATION...VFR ATTM. MVFR CLOUDS AND SNOW TO MOVE INTO COASTAL AND SOUTHERN FOOTHILL LOCATIONS TONIGHT. && .MARINE...SEAS STILL JUST BELOW SCA. WILL BUMP WINDS DOWN TODAY ON THE UPDATE FOLLOWING LATEST RUC/ETA. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ UPDATE: APFFEL me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1110 AM EST SAT DEC 25 2004 .DISCUSSION... MAIN FORECAST CONCERN IN THE SHORT TERM IS CURRENT HEADLINES AND LES POTENTIAL ALONG THE LAKE MICHIGAN SHORE THROUGH TONIGHT. LATEST 88D IMAGERY AND SURFACE OBS SHOW LIGHT SNOW ACROSS MUCH OF THE CWFA AT THIS TIME. THIS SNOW IS IN ASSOCIATION WITH A VORT LOBE ROTATING AROUND THE UPPER LOW TO OUR NORTH AND SOME MID-LEVEL WARM ADVECTION ASSOCIATED WITH THE WEAK SURFACE LOW MOVING SOUTHEAST OVER IOWA. THE 850-500MB Q-VECTOR CONVERGENCE PROGS FROM THE 12Z ETA APPEAR TO HAVE A DECENT HANDLE ON THIS AREA OF LARGE SCALE FORCING...AND MOVE IT OUT OF THE WESTERN CWFA BY 18Z AND OUT OF THE REMAINDER OF THE CWFA BY AROUND 21Z. THE FORCING IS NOT PARTICULARLY STRONG...AND LOW LEVEL MOISTURE IS SOMEWHAT LIMITED PER ETA PROGS AND 12Z KGRB AND KAPX SOUNDINGS...SO ANY ACCUMULATIONS FROM THIS SYNOPTIC SCALE FORCING SHOULD BE MINIMAL. THE BIGGER QUESTION FOR TODAY IS WITH REGARD TO THE LAKE EFFECT SNOW SHOWERS OVER LAKE MICHIGAN. 88D IMAGERY FROM KGRB SHOWS A WELL-DEFINED MID-LAKE LES BAND ON LAKE MICHIGAN...WITH SURFACE OBS ON BOTH SIDES OF THE LAKE CLEARLY SHOWING CONVERGENCE INTO THE BAND. THE BAND IS ORIENTED SOUTH-NORTH TO THE END OF THE DOOR PENINSULA...THEN BENDS OFF TO THE NORTHEAST...WITH A PORTION BEGINNING TO MOVE ONSHORE IN SCHOOLCRAFT COUNTY. IT IS VERY DIFFICULT TO GET A HANDLE ON HOW THIS BAND WILL EVOLVE THROUGH TODAY AND TONIGHT. THE SYNOPTIC SCALE FEATURES SUGGEST THE BAND SHOULD HAVE A TENDENCY TO BE PUSHED FARTHER NORTH AND PERHAPS A BIT EAST THIS AFTERNOON AS THE LARGE SCALE SOUTHERLY FLOW ASSOCIATED WITH THE SURFACE LOW MOVING BY TO THE SOUTH HELPS IMPACT THE MESOSCALE FLOW OVER THE LAKE. HOWEVER...BY LATE AFTERNOON AND TONIGHT THINGS BECOME MUCH MORE DIFFICULT TO ASSESS/PREDICT. WHAT IS LEFT OF THE SURFACE LOW WILL BE MOVING INTO THE OHIO VALLEY...WHICH IN COMBINATION WITH THE ARCTIC HIGH TO THE NORTH...SHOULD HELP ASSIST EASTERLY FLOW OVER THE REGION. HOWEVER...LAKE INDUCED TROUGHING OVER LAKE MICHIGAN MAY WORK TO LIMIT HOW FAR WESTWARD THE BAND CAN BE PUSHED. AN ASSESSMENT OF CURRENT TRENDS SUGGESTS THAT THE ACTIVITY SHOULD CONTINUE TO AFFECT EASTERN DELTA COUNTY THIS AFTERNOON...AND SHOULD WORK INTO SOUTHERN SCHOOLCRAFT COUNTY. OUTPUT FROM THE LOCAL 3.75KM WORKSTATION ETA OFFERS WHAT COULD BE A VERY PRECISE YET INACCURATE FORECAST. THE 00Z RUN OF THE WORKSTATION ETA HAD A BETTER HANDLE ON THE CURRENT ACTIVITY THAN ANY OTHER AVAILABLE GUIDANCE...INCLUDING THE NEW 12Z WORKSTATION ETA. HOWEVER...THAT RUN SEEMED TO UNREALISTICALLY SHIFT THE BAND TO FAR EASTWARD LATER THIS AFTERNOON...ALLOWING IT TO SURGE THROUGH SOUTHEASTERN SCHOOLCRAFT COUNTY NORTH INTO LUCE COUNTY. THE 12Z WSETA RUN MAINTAINS MORE EASTERLY FLOW WHICH HELPS TO KEEP THINGS FROM AFFECTING LUCE COUNTY OTHER THAN FOR A SHORT TIME LATE THIS AFTERNOON. LES BANDS IN FAIRLY QUIESCENT CONDITIONS SUCH AS THIS ARE VERY DIFFICULT TO PREDICT...AND UNFORTUNATELY THE STRONG CONVERGENCE WHICH CAN BE ASSOCIATED WITH THEM CAN LEAD TO IMPRESSIVE ALBEIT LOCALIZED SNOWFALL RATES. GIVEN THE UNCERTAINTY AND DISAGREEMENT AMONGST THE VARIOUS MESOSCALE MODEL OUTPUT...INCLUDING WSETA...ETA12...AND RUC13...AM INCLINED TO NOT MAKE MANY CHANGES TO THE GOING FORECAST. SINCE THE 00Z WSETA SEEMS TO BE HANDLING THE CURRENT STRUCTURE OF THE BANDING BEST...PREFER TO WAIT AND SEE HOW THINGS EVOLVE THROUGH THE AFTERNOON BEFORE MAKING ANY ADJUSTMENTS. ADJUSTMENTS THAT MAY BE NEEDED LATER INCLUDE THE POSSIBLE REMOVAL OF LUCE COUNTY FROM THE ADVISORY AND THE EXTENSION IN TIME OF THE ADVISORY OVER DELTA AND POSSIBLY SOUTHERN SCHOOLCRAFT COUNTY...SINCE MOST GUIDANCE SUGGESTS IT WILL LINGER INTO SUNDAY MORNING. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 11 PM EST MIZ007-014-085. && $$ TRH mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1000 AM EST SAT DEC 25 2004 .SHORT TERM /TODAY AND TONIGHT/...DENSE MID LEVEL OVERCAST ORIGINATING FROM CONVECTION IN THE EASTERN GULF OF MEXICO COVERS MUCH OF THE SOUTHEASTERN STATES. SOME VERY LIGHT RAIN OCCURRING ACROSS THE NORTHERN PORTION OF FLORIDA MOVING MAINLY TO THE EAST. PRECIPITATION ACROSS SOUTHERN PORTIONS OF MISSISSIPPI AND ALABAMA MAKING A LITTLE MORE NORTHWARD PROGRESS...BUT THAT NOT LIKELY TO IMPACT THE AREA UNTIL TONIGHT. BOTTOM LINE FOR TODAY...LOW LEVEL DRY AIR ADVECTING INTO THE AREA WILL LIMIT THE CHANCE FOR ANY PRECIPITATION REACHING THE GROUND IN THE NORTHWESTERN PART OF THE AREA. CANNOT RULE OUT A VERY LIGHT SHOWER OR SPRINKLE ELSEWHERE...SO WILL CONTINUE WITH SLIGHT CHANCE OF RAIN IN MOST AREAS AND CHANCE IN THE EXTREME SOUTHEAST. THINK THIS AFTERNOON WILL BE JUST PLAIN CLOUDY SO WILL WORD ACCORDINGLY. BASED ON EXPECTED CLOUD COVER...WEAK COLD ADVECTION AND CURRENT TEMPERATURES AND TRENDS...WILL LOWER HIGH TEMPERATURES INTO THE LOWER TO MID 40S MOST AREAS. FOR TONIGHT...HAVE NOT MADE ANY CHANGES AS OF YET...BUT AT A MINIMUM FEEL THAT POPS AND LIQUID PRECIPITATION AMOUNTS MAY NEED TO BE RAISED. MORE ON LATE LATER THIS AFTERNOON. && .MARINE...MODEST PRES GRAD CURRENTLY OVR THE WATERS WILL ONLY BECOME TIGHTER THRU THE NEXT 12-24 HRS AS A VIGOROUS LOW PRES CNTR GETS STIRRED UP IN THE GULF AND MOVES NE ALONG A STALLED FNTL BNDRY. WILL KEEP HEADLINES AS IS IN GOING CWF...BUT AM CONCERNED WITH 41004 ALREADY TOYING WITH THE 7FT MARK. MAY WELL HAVE 6 FT JUST BEYOND 20NM BOUNDARY OF AMZ350 FOR MOST OF THE DAY. FOR NOW...WILL MAX WAVES WITHIN 20NM AT 5 FT AND MAINTAIN LOWER WAVES CLOSER TO SHORE. WINDS LOOK RIGHT ON TRACK WITH BUOYS AND SHORELINE OBS COMING IN WITH SUSTAINED 15-20 KT WINDS. RUC/M-ETA DO NOT SHOW AN APPRECIATIVE INCRS IN WIND SPEEDS UNTIL AFT 00Z SO SHOULD BE ABLE TO LEAVE RANGES AS IS. WILL MAKE COSMETIC WORDING CHANGES BUT ALL WX ELEMENTS GOOD. && .AVIATION...CURRENT TAFS LOOK TO HAVE SKY CONDS HANDLED WELL WITH OVC CIGS ABV 12K FT. AS THE LOW IN THE GULF APCHS...CIGS SHOULD FALL TO WHERE ASOS WILL DETECT THEM. CIGS WILL CONTINUE TO FALL THRU THE AFTN AND EVE HRS...ESP IS SCT -RA MOVE NR/OVR THE TERMINALS. WINDS WILL ALSO GRADUALLY INCRS AT BOTH AIRPORTS AND PRECIP WILL LIKELY BECOME PREVAILING...BOTH ELEMENTS HANDLED WELL IN CURRENT TAFS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...WINTER WEATHER ADVISORY GAZ087-088 FOR LATE TONIGHT INTO SUNDAY MORNING. SC...WINTER WEATHER ADVISORY SCZ040-042>045 FOR LATE TONIGHT INTO SUNDAY MORNING. MARINE...SMALL CRAFT ADVISORY AMZ374. && $$ MTE/JPC sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 942 AM EST SAT DEC 25 2004 .DISCUSSION...A VERY QUIET AND CHILLY CHRISTMAS MORNING ACROSS THE REGION. ONLY ITEM OF ANY CONCERN AT ALL IS HOW MUCH HIGH CLOUDINESS AFFECTS THE EASTERN AND SOUTHERN MOST PARTS OF OUR FORECAST AREA. LATEST SATELLITE LOOPS SHOW CLEAR SKIES ABOUND...WITH LATEST RUC AND MESO-ETA MODELS NOT INDICATING MUCH IF ANY OF THE HIGH CLOUDS PASSING OVER MY AREA TODAY OR TONIGHT. HOWEVER...AS GULF COAST LOW PRESSURE MOVES ENE TODAY A FEW HIGH CLOUDS MAY AT LEAST BRUSH THESE AREAS. 12Z OHX AND RNK SOUNDINGS SUGGEST HIGHS MOSTLY IN THE 30S TODAY...IN SPITE OF FULL SUNSHINE. THIS SEEMS REASONABLE WITH CURRENT TEMPS ONLY IN THE TEENS TO LOWER 20S. WILL DO A COSMETIC UPDATE AND REMOVE ANY MORNING WORDING...OTHERWISE THE ZFP...GRIDS AND WEB PRODUCTS NEED LITTLE IF ANY UPDATING FOR REST OF TODAY. HAPPY HOLIDAYS TO ALL! && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ TG tn AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 8 AM CST SAT DEC 25 2004 .DISCUSSION... WILL DROP THE WINTER WEATHER WARNING FOR THE COASTAL COUNTIES AS ALL THAT IS LEFT IS A FEW FLURRIES ALONG THE IMMEDIATE COAST. HAVE ISSUED A PNS WITH A SNOWFALL SUMMARY SO FAR THIS MORNING. THIS CAN BE FOUND ON OUR WEBSITE UNDER ADDITIONAL INFORMATION > ADDITIONAL INFO/LINKS > PUBLIC INFORMATION STATEMENT. FORGOT TO MENTION THAT WE HAVE ISSUED CEMS FOR THE CITY OF HOUSTON AND WHARTON COUNTIES FOR TRAVEL ADVISORIES DUE TO SLICK/ICY ROADS IN HOUSTON AND SNOW COVERED AND IMPASSABLE ROADS IN WHARTON COUNTY. 45. .PREVIOUS DISCUSSIONS... THE BIG CHRISTMAS EVE STORM IS WINDING DOWN FOR SOUTHEAST TEXAS. MUCH OF THE SOUTHERN PORTIONS OF SOUTHEAST TEXAS WILL BE WAKING UP TO A WHITE CHRISTMAS. SNOWFALL TOTALS OF 8 INCHES IN BAY CITY AND 4 INCHES IN WHARTON...TAPERING OFF TO 2 INCHES IN LEAGUE CITY AND 2 TO 3 INCHES AT JAMAICA BEACH. WOW! THE AREA HASN'T SEEN THIS KIND OF SNOWFALL SINCE AT LEAST 1989. THE GOOD NEWS IS THAT THE STORM SYSTEM NEAR THE COASTAL BEND IS MOVING STEADILY EAST-NORTHEAST AT 20 TO 25 MPH AND SHOULD BE PUSHING INTO THE GULF. TEMPERATURES AT 5 AM AT COLLEGE STATION 29...CONROE 32...IAH 35...WHARTON 30...PALACIOS 29...ANGLETON 30...AND GALVESTON 36. CLOUDS OVER THE AREA HAVE KEPT THE TEMPERATURES MUCH WARMER THAN WERE PREVIOUSLY FORECAST THAT HAS BEEN VERY GOOD NEWS THOUGH THE CLOUDS ARE SHOWING SIGNS OF CLEARING OUT FROM THE FAR NORTHWEST. WHERE THE HEAVIER SNOW FELL TEMPERATURES ARE STILL AROUND 30 BUT IN MANY OF THE SOUTHERN SITES THE TEMPERATURES HAVE BEEN COMING UP THE LAST FEW HOURS...MORE GOOD NEWS. WILL BE EXTENDING THE WINTER WEATHER WARNING UNTIL 8 AM FOR THE COASTAL COUNTIES AND HAVE CANCELLED IT ELSEWHERE. SATELLITE...METARS AND RADAR INDICATING THAT THE SNOW IS TAPERING OFF AND COMING TO AN END. THIS SYSTEM SHOULD BE WELL EAST OF THE AREA BY THIS AFTERNOON WITH THE COASTAL WATERS STILL UNDER THE INFLUENCE THROUGH MID AFTERNOON. SHOULD BE PRIMARILY RAIN WITH EMBEDDED ISOLATED THUNDERSTORMS. RIDGE BUILDS IN AND BRINGS CLEARING SKIES FROM THE NORTHWEST THIS AFTERNOON. THEN A SLOW WARMUP AS RIDGE AXIS LINGERS ALONG THE COAST FROM SUNDAY THROUGH WEDNESDAY. VIGOROUS UPPER LOW DROPS DOWN THE WEST COAST AND A VERY DEEP TROUGH TAKING SHAPE FOR THE END OF THE WEEK. COULD GET STORMY FRIDAY OR SATURDAY. 45 && .MARINE... EXPECT TIGHT GRADIENTS TO PERSIST OVER THE GULF THROUGH MID DAY TODAY... SO WILL LEAVE SCA FLAGS UP 0-60 NM. FOR THE BAYS... WINDS STILL AT CAUTION LEVELS... AND THOUGH THEY MAY DROP MORE RAPIDLY THAN THE GULF WATERS... WILL STILL KEEP SCEC IN EFFECT FOR FIRST PERIOD FORECAST. HARD TO DELINEATE EXACTLY WHERE SNOW STOPS AND RAIN TAKES OVER IN THE COASTAL WATERS... BUT TRANSITION ALMOST CERTAINLY COMPLETE BYD 20 NM WHERE ECHO GRADIENTS JUMP INTO THE 40-50 DBZ RANGE. AT ISSUE HERE IS THAT AREAS WITHIN 20 NM OF SHORE MAY HAVE BRIEF PERIODS OF VSBY DOWN TO 1NM IN LIGHT SNOW. AS UPPER TROUGH CROSSES THE COASTAL WATERS LATER TODAY...PRECIP SHOULD MOVE OUT OF THE REGION AND WINDS RELAX SUBSTANTIALLY BETWEEN 18-00Z. 38 && .AVIATION... IFR CIGS/VSBY WILL BE RESTRICTED THIS MORNING IN AREAS WHERE SNOW CONTINUES. THE PRECIP IS BEING SHUT OFF ON THE NORTH SIDE BY MID LEVEL CONFLUENCE WHICH ARCS FROM EAGLE LAKE TO ANAHUAC AT 08Z AND IS BEST DEPICTED IN 700 MB RUC. HOBBY WILL REMAIN ON THE CUSP OF THIS FEATURE... BUT EXPECTED TO HOVER AT MVFR CONDITIONS. IFR CONDITIONS WILL REMAIN CLOSER TO THE COAST WHERE LIGHT TO MODERATE SNOW WILL LIKELY CONTINUE THROUGH AROUND 15Z. NORTH OF KHOU - WHERE SNOW WILL NOT BE MUCH OF AN ISSUE - EXTENSIVE CLOUD DECK REMAINS WITH BASES 6-10KFT AND THIS WILL REMAIN IN PLACE UNTIL IT IS LIFTED OUT THIS AFTERNOON WITH THE MOTION OF THE UPPER LEVEL TROUGH DRIVING THIS SYSTEM. 38 && .HGX WATCHES/WARNINGS/ADVISORIES... SCEC BAYS. SCA 00-60 NM WATERS. && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 45 27 57 36 61 / 00 00 00 00 00 HOUSTON (IAH) 44 28 56 36 62 / 00 00 00 00 00 GALVESTON (GLS) 40 37 53 48 60 / 05 00 00 00 00 && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 744 AM CST SAT DEC 25 2004 .DISCUSSION... UPDATE... WILL DROP THE WINTER WEATHER WARNING FOR THE COASTAL COUNTIES AS ALL THAT IS LEFT IS A FEW FLURRIES ALONG THE IMMEDIATE COAST. HAVE ISSUED A PNS WITH A SNOWFALL SUMMARY SO FAR THIS MORNING. THIS CAN BE FOUND ON OUR WEBSITE UNDER ADDITIONAL INFORMATION > ADDITIONAL INFO/LINKS > PUBLIC INFORMATION STATEMENT. 45. .PREVIOUS DISCUSSIONS... THE BIG CHRISTMAS EVE STORM IS WINDING DOWN FOR SOUTHEAST TEXAS. MUCH OF THE SOUTHERN PORTIONS OF SOUTHEAST TEXAS WILL BE WAKING UP TO A WHITE CHRISTMAS. SNOWFALL TOTALS OF 8 INCHES IN BAY CITY AND 4 INCHES IN WHARTON...TAPERING OFF TO 2 INCHES IN LEAGUE CITY AND 2 TO 3 INCHES AT JAMAICA BEACH. WOW! THE AREA HASN'T SEEN THIS KIND OF SNOWFALL SINCE AT LEAST 1989. THE GOOD NEWS IS THAT THE STORM SYSTEM NEAR THE COASTAL BEND IS MOVING STEADILY EAST-NORTHEAST AT 20 TO 25 MPH AND SHOULD BE PUSHING INTO THE GULF. TEMPERATURES AT 5 AM AT COLLEGE STATION 29...CONROE 32...IAH 35...WHARTON 30...PALACIOS 29...ANGLETON 30...AND GALVESTON 36. CLOUDS OVER THE AREA HAVE KEPT THE TEMPERATURES MUCH WARMER THAN WERE PREVIOUSLY FORECAST THAT HAS BEEN VERY GOOD NEWS THOUGH THE CLOUDS ARE SHOWING SIGNS OF CLEARING OUT FROM THE FAR NORTHWEST. WHERE THE HEAVIER SNOW FELL TEMPERATURES ARE STILL AROUND 30 BUT IN MANY OF THE SOUTHERN SITES THE TEMPERATURES HAVE BEEN COMING UP THE LAST FEW HOURS...MORE GOOD NEWS. WILL BE EXTENDING THE WINTER WEATHER WARNING UNTIL 8 AM FOR THE COASTAL COUNTIES AND HAVE CANCELLED IT ELSEWHERE. SATELLITE...METARS AND RADAR INDICATING THAT THE SNOW IS TAPERING OFF AND COMING TO AN END. THIS SYSTEM SHOULD BE WELL EAST OF THE AREA BY THIS AFTERNOON WITH THE COASTAL WATERS STILL UNDER THE INFLUENCE THROUGH MID AFTERNOON. SHOULD BE PRIMARILY RAIN WITH EMBEDDED ISOLATED THUNDERSTORMS. RIDGE BUILDS IN AND BRINGS CLEARING SKIES FROM THE NORTHWEST THIS AFTERNOON. THEN A SLOW WARMUP AS RIDGE AXIS LINGERS ALONG THE COAST FROM SUNDAY THROUGH WEDNESDAY. VIGOROUS UPPER LOW DROPS DOWN THE WEST COAST AND A VERY DEEP TROUGH TAKING SHAPE FOR THE END OF THE WEEK. COULD GET STORMY FRIDAY OR SATURDAY. 45 && .MARINE... EXPECT TIGHT GRADIENTS TO PERSIST OVER THE GULF THROUGH MID DAY TODAY... SO WILL LEAVE SCA FLAGS UP 0-60 NM. FOR THE BAYS... WINDS STILL AT CAUTION LEVELS... AND THOUGH THEY MAY DROP MORE RAPIDLY THAN THE GULF WATERS... WILL STILL KEEP SCEC IN EFFECT FOR FIRST PERIOD FORECAST. HARD TO DELINEATE EXACTLY WHERE SNOW STOPS AND RAIN TAKES OVER IN THE COASTAL WATERS... BUT TRANSITION ALMOST CERTAINLY COMPLETE BYD 20 NM WHERE ECHO GRADIENTS JUMP INTO THE 40-50 DBZ RANGE. AT ISSUE HERE IS THAT AREAS WITHIN 20 NM OF SHORE MAY HAVE BRIEF PERIODS OF VSBY DOWN TO 1NM IN LIGHT SNOW. AS UPPER TROUGH CROSSES THE COASTAL WATERS LATER TODAY...PRECIP SHOULD MOVE OUT OF THE REGION AND WINDS RELAX SUBSTANTIALLY BETWEEN 18-00Z. 38 && .AVIATION... IFR CIGS/VSBY WILL BE RESTRICTED THIS MORNING IN AREAS WHERE SNOW CONTINUES. THE PRECIP IS BEING SHUT OFF ON THE NORTH SIDE BY MID LEVEL CONFLUENCE WHICH ARCS FROM EAGLE LAKE TO ANAHUAC AT 08Z AND IS BEST DEPICTED IN 700 MB RUC. HOBBY WILL REMAIN ON THE CUSP OF THIS FEATURE... BUT EXPECTED TO HOVER AT MVFR CONDITIONS. IFR CONDITIONS WILL REMAIN CLOSER TO THE COAST WHERE LIGHT TO MODERATE SNOW WILL LIKELY CONTINUE THROUGH AROUND 15Z. NORTH OF KHOU - WHERE SNOW WILL NOT BE MUCH OF AN ISSUE - EXTENSIVE CLOUD DECK REMAINS WITH BASES 6-10KFT AND THIS WILL REMAIN IN PLACE UNTIL IT IS LIFTED OUT THIS AFTERNOON WITH THE MOTION OF THE UPPER LEVEL TROUGH DRIVING THIS SYSTEM. 38 && .HGX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER WARNING FOR COASTAL COUNTIES OF SE TX UNTIL 14Z. SCEC BAYS. SCA 00-60 NM WATERS. && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 45 27 57 36 61 / 00 00 00 00 00 HOUSTON (IAH) 44 28 56 36 62 / 20 00 00 00 00 GALVESTON (GLS) 41 37 53 48 60 / 50 00 00 00 00 && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 537 AM CST SAT DEC 25 2004 THE BIG CHRISTMAS EVE STORM IS WINDING DOWN FOR SOUTHEAST TEXAS. MUCH OF THE SOUTHERN PORTIONS OF SOUTHEAST TEXAS WILL BE WAKING UP TO A WHITE CHRISTMAS. SNOWFALL TOTALS OF 8 INCHES IN BAY CITY AND 4 INCHES IN WHARTON...TAPERING OFF TO 2 INCHES IN LEAGUE CITY AND 2 TO 3 INCHES AT JAMAICA BEACH. WOW! THE AREA HASN'T SEEN THIS KIND OF SNOWFALL SINCE AT LEAST 1989. THE GOOD NEWS IS THAT THE STORM SYSTEM NEAR THE COASTAL BEND IS MOVING STEADILY EAST-NORTHEAST AT 20 TO 25 MPH AND SHOULD BE PUSHING INTO THE GULF. TEMPERATURES AT 5 AM AT COLLEGE STATION 29...CONROE 32...IAH 35...WHARTON 30...PALACIOS 29...ANGLETON 30...AND GALVESTON 36. CLOUDS OVER THE AREA HAVE KEPT THE TEMPERATURES MUCH WARMER THAN WERE PREVIOUSLY FORECAST THAT HAS BEEN VERY GOOD NEWS THOUGH THE CLOUDS ARE SHOWING SIGNS OF CLEARING OUT FROM THE FAR NORTHWEST. WHERE THE HEAVIER SNOW FELL TEMPERATURES ARE STILL AROUND 30 BUT IN MANY OF THE SOUTHERN SITES THE TEMPERATURES HAVE BEEN COMING UP THE LAST FEW HOURS...MORE GOOD NEWS. WILL BE EXTENDING THE WINTER WEATHER WARNING UNTIL 8 AM FOR THE COASTAL COUNTIES AND HAVE CANCELLED IT ELSEWHERE. SATELLITE...METARS AND RADAR INDICATING THAT THE SNOW IS TAPERING OFF AND COMING TO AN END. THIS SYSTEM SHOULD BE WELL EAST OF THE AREA BY THIS AFTERNOON WITH THE COASTAL WATERS STILL UNDER THE INFLUENCE THROUGH MID AFTERNOON. SHOULD BE PRIMARILY RAIN WITH EMBEDDED ISOLATED THUNDERSTORMS. RIDGE BUILDS IN AND BRINGS CLEARING SKIES FROM THE NORTHWEST THIS AFTERNOON. THEN A SLOW WARMUP AS RIDGE AXIS LINGERS ALONG THE COAST FROM SUNDAY THROUGH WEDNESDAY. VIGOROUS UPPER LOW DROPS DOWN THE WEST COAST AND A VERY DEEP TROUGH TAKING SHAPE FOR THE END OF THE WEEK. COULD GET STORMY FRIDAY OR SATURDAY. 45 && .MARINE... EXPECT TIGHT GRADIENTS TO PERSIST OVER THE GULF THROUGH MID DAY TODAY... SO WILL LEAVE SCA FLAGS UP 0-60 NM. FOR THE BAYS... WINDS STILL AT CAUTION LEVELS... AND THOUGH THEY MAY DROP MORE RAPIDLY THAN THE GULF WATERS... WILL STILL KEEP SCEC IN EFFECT FOR FIRST PERIOD FORECAST. HARD TO DELINEATE EXACTLY WHERE SNOW STOPS AND RAIN TAKES OVER IN THE COASTAL WATERS... BUT TRANSITION ALMOST CERTAINLY COMPLETE BYD 20 NM WHERE ECHO GRADIENTS JUMP INTO THE 40-50 DBZ RANGE. AT ISSUE HERE IS THAT AREAS WITHIN 20 NM OF SHORE MAY HAVE BRIEF PERIODS OF VSBY DOWN TO 1NM IN LIGHT SNOW. AS UPPER TROUGH CROSSES THE COASTAL WATERS LATER TODAY...PRECIP SHOULD MOVE OUT OF THE REGION AND WINDS RELAX SUBSTANTIALLY BETWEEN 18-00Z. 38 && .AVIATION... IFR CIGS/VSBY WILL BE RESTRICTED THIS MORNING IN AREAS WHERE SNOW CONTINUES. THE PRECIP IS BEING SHUT OFF ON THE NORTH SIDE BY MID LEVEL CONFLUENCE WHICH ARCS FROM EAGLE LAKE TO ANAHUAC AT 08Z AND IS BEST DEPICTED IN 700 MB RUC. HOBBY WILL REMAIN ON THE CUSP OF THIS FEATURE... BUT EXPECTED TO HOVER AT MVFR CONDITIONS. IFR CONDITIONS WILL REMAIN CLOSER TO THE COAST WHERE LIGHT TO MODERATE SNOW WILL LIKELY CONTINUE THROUGH AROUND 15Z. NORTH OF KHOU - WHERE SNOW WILL NOT BE MUCH OF AN ISSUE - EXTENSIVE CLOUD DECK REMAINS WITH BASES 6-10KFT AND THIS WILL REMAIN IN PLACE UNTIL IT IS LIFTED OUT THIS AFTERNOON WITH THE MOTION OF THE UPPER LEVEL TROUGH DRIVING THIS SYSTEM. 38 && .HGX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER WARNING FOR COASTAL COUNTIES OF SE TX UNTIL 14Z. SCEC BAYS. SCA 00-60 NM WATERS. && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 45 27 57 36 61 / 00 00 00 00 00 HOUSTON (IAH) 44 28 56 36 62 / 20 00 00 00 00 GALVESTON (GLS) 41 37 53 48 60 / 50 00 00 00 00 && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 330 PM CST SAT DEC 25 2004 .SYNOPTIC...THE LOW PRESSURE SYSTEM IN THE NORTHERN GULF WILL SHIFT EAST AND END THE CHANCE OF WINTRY PRECIPITATION IN THE SOUTH. A WARMING TREND WILL BEGIN SUNDAY WITH ABOVE NORMAL TEMPERATURES EXPECTED BY THE MIDDLE OF NEXT WEEK. THE NEXT BEST CHANCE FOR RAIN IS EXPECTED TOWARD THE END OF NEXT WEEK. && .SHORT TERM...TONIGHT THROUGH TUESDAY...MOST SITES IN OUR CWA ARE REPORTING TEMPERATURES ABOVE FREEZING THIS AFTERNOON AND FOR SOME NORTHERN LOCATIONS...FIRST TIME ABOVE FREEZING IN THE LAST TWO DAYS. ALL WINTRY PCPN HAS BEEN SOUTH OF THE CWA THIS AFTERNOON AND IS EXPECTED TO REMAIN SOUTH THIS EVENING. WL INCLUDE MENTION OF SPRINKLES IN OUR SOUTHEASTERN MOST ZONES THIS EVENING THOUGH. IMPRESSIVE SATELLITE IMAGERY AND RUC ANALYSIS HAS A DEEPENING SURFACE LOW IN THE CENTRAL GULF OF MEXICO...SOUTH OF PENSACOLA MOVING EAST. THIS LOW IS BEING TRAILED BY AN UPPER LOW WHOSE CYCLONIC CIRCULATION IS CLEARLY SEEN ON VISIBLE SATELLITE IMAGERY SOUTHEAST OF LAKE CHARLES. WRAP AROUND CLOUDS FROM THESE LOWS MAY BRIEFLY BRING A FEW SPRINKLES INTO THE HATTIESBURG AREA THIS EVENING BEFORE THE SYSTEM SHIFTS EAST OF THE AREA TONIGHT. THE BACK EDGE OF THE CLOUD SHIELD IS NEAR A GREENVILLE MS TO MONROE LA LINE. THE EDGE OF THE CLOUD SHIELD WILL PROGRESS EASTWARD OVER NIGHT AND PLENTY OF SUNSHINE IS EXPECTED SUNDAY. WITH CLEARING SKIES...LIGHT WINDS AND OUR COLD AIRMASS OVER THE REGION TEMPERATURES WILL AGAIN DROP BELOW FREEZING SHORTLY AFTER SUNSET. TEMPERATURES ARE EXPECTED TO DROP INTO THE 20S OVERNIGHT BUT REMAIN ABOVE THE TEENS SO A HARD FREEZE WARNING WILL NOT BE ISSUED TONIGHT. RIDGING SURFACE AND ALOFT WILL BUILD OVER OUR REGION SUNDAY THROUGH TUESDAY WITH PROGRESSIVELY WARMER TEMPERATURES. && .LONG TERM...WEDNESDAY THROUGH SATURDAY...BY WEDNESDAY WL HAVE ZONAL FLOW ALOFT AND A SURFACE RIDGE OF HIGH PRESSURE OVER THE GULF STATES. ONLY WEAK RETURN FLOW IS EXPECTED OVER THE REGION AS A DISTURBANCE MOVES EAST ACROSS THE UPPER MISSISSIPPI VALLEY. WL REMOVE MENTION OF POPS WEDNESDAY AND KEEP THINGS DRY UNTIL THE END OF THE WEEK. THE UPPER LEVELS WILL BEGIN TO AMPLIFY THURSDAY THROUGH SATURDAY WITH A TROUGH IN THE WEST AND A RIDGE IN THE EAST. DEEP MOISTURE WILL GRADUALLY INCREASE THROUGH THE PERIOD. SCATTERED SHOWERS ARE EXPECTED TO DEVELOP IN OUR WESTERN ZONES AND PARISHES FRIDAY AHEAD OF A SLOWLY APPROACHING COLD FRONT. GFSLR AND ECMWF BOTH STALL THIS COLD FRONT OVER THE OZARKS SATURDAY AS THE BOUNDARY BECOMES PARALLEL TO THE UPPER FLOW. A FEW WEAK DISTURBANCES IN THE SOUTHWEST FLOW ALOFT WILL MAINTAIN A CHANCE OF RAIN IN THE FORECAST THROUGH SATURDAY WITH THE HIGHEST POPS WEST OF THE MISSISSIPPI RIVER. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 25 50 30 55 / 0 0 0 0 MERIDIAN 24 50 27 55 / 0 0 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 22 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 350 PM CST SAT DEC 25 2004 .DISCUSSION... WK SFC LO NR KOMA THIS AFTN WL CONT RIDING ALG ARCTIC FNT AND DROP E-SE TNGT. WAA AHD OF THIS FTR...ALG WITH A BIT OF SHTWV ENERGY...HAS BEEN KICKING OFF AN AREA OF LGT SNW OVR CNTR/E IA THIS AFTN. EXTRAPOLATION OF CURRENT RADAR TRENDS...AS WELL AS MDL OUTPUT...SUGGESTS THAT THE BULK OF THIS PCPN WL RMN JUST OUT OF OUR CWA. WL MENTION A FEW FLRYS OVR OUR FAR NE COUNTIES DURG THE EVE HRS...BUT WL CONT DRY FCST ELSW. OTRW...MAIN FCST PROB FOR MUCH OF THE UPCOMING WEEK IS TEMP TRENDS. FUNDAMENTAL SHIFT APRS TO BE UNDERWAY IN THE UA PTRN...AS LGWV TROF THAT HAS BEEN PARKED OVR CNTRL U.S. GIVES WAY TO RDGG AND QZNL FLOW. ALL SHORT RANGE MDL OUTPUT APRS TO BE IN VRY GD AGREEMENT WITH THE ABV MENTIONED TREND...AND RESULTANT TEMP PROFILE OVR REGION. A BIT UNSURE ON HOW TO HNDL ARCTIC AIRMASS THAT SHUD SAG ACR AREA ON SUN IN WAKE OF TNGTS LOW. AMS JUST N OF FNT IS QUITE CHILLY...WHILE PRONOUNCED DOWNSLOPE EFFECT HAS REALLY WARMED AMD FROM CNTRL PLAINS INTO SW MO AHD OF FNT. 18Z RUNS...AND LATEST RUC...APR TO BE HEADING TWD A BIT MORE OF A N TRACK OF THE SFC LO TNGT...WHICH SHUD TRANSLATE TO A BIT LESS SWD PUSH OF THE ARCTIC AMS BY SUN MRNG. MAY END UP WITH A FAIRLY BIG TEMP GRADIENT ACR AREA BY SUN AFTN...AND TO EMPHASIZE THIS HV LEANED ON THE COOL SIDE OF GUID IN N AREAS...AND TWD THE WRMR MET NUMBERS IN THE SNW FREE AREAS OF S PARTS OF OUR CWA. A BIG WRMUP SHUD BEGIN IN EARNEST BY MON...WITH THIS WRMG TREND CONTG THRUOUT RMNDR OF WEEK. SHT RANGE MOS GUID IN VRY GD AGREEMENT AND SEE NO REASON TO ALTER...OTHER THAN TO ACCOUNT FOR RESIDUAL SNWCVR OVR SE AREAS THRU MON. BLV THAT BY TUE SNWCVR WL BE A NON-ISSUE FOR OUR AREA AS FAR AS TEMPS ARE CONCERNED. THANKS TO PAH FOR COORD ON THIS. HEADING INTO THE MEDIUM RANGE...TEMPS SHUD RMN WELL ABV NORMAL AS QZNL FLO KPS COLD AIR LOCKED TO OUR N. ATTM HV OPTED TO GO NR ENSEMBLE MOS MEANS FOR NOW...JUST A BIT BLO OPERATIONAL GUID...AS RH PROGS SUGGEST QUITE A BIT OF CLDNS IN THE LTR PDS...ALG WITH A CHC OF RAIN. && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ TRUETT mo