FXUS64 KHUN 122346 AFDHUN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HUNTSVILLE AL 546 PM CST WED FEB 12 2014 .UPDATE... FOR 00Z TAFS && .DISCUSSION... /ISSUED 401 PM CST WED FEB 12 2014/ AS MOST KNOW...A VERY COMPLEX WEATHER PATTERN CONTINUES ACROSS THIS REGION. A MUCH TALKED STORM SYSTEM CONTINUED TO TAKE SHAPE ACROSS THE SE STATES...WITH ITS SURFACE LOW FORMING SOUTH OF THE WESTERN FLORIDA PANHANDLE. THIS LOW IS FORECAST TO FURTHER DEVELOP AS IT TRACKS TO THE NORTHEAST...AND BRING A VARIETY OF WEATHER OVER MUCH OF THE EASTERN STATES FOR THE NEXT COUPLE OF DAYS. ANALYSIS WISE...TROUGHING WAS EXTENDING SOUTHWARD FROM LOW PRESSURE JUST SOUTH OF THE HUDSON BAY. A MIX OF SUBTROPICAL/NORTHERN STREAM MOISTURE WAS MOVING EASTWARD FROM THE EAST PACIFIC TO THE CENTRAL HIGH PLAINS. CONVECTION WAS FORMING EAST OF THE TROUGH FROM THE YUCATAN TO WEST OF TAMPA. AT THE SURFACE...COLD AIR DAMMING WAS IN PLACE EAST OF HERE...COURTESY OF COLD HIGH PRESSURE OVER THE NEW ENGLAND REGION. DESPITE GENERALLY COOL CONDITIONS ACROSS THIS REGION... CRITICAL SLIGHTLY WARMER TEMPERATURES AT SURFACE AND ALOFT HAVE RESULTED IN THE PRECIP FALLING ACROSS MOST OF THE AREA AS SIMPLE RAIN RATHER THAN SNOW. LOCAL MORNING SOUNDINGS AT 14Z FROM UAH REVEALED A WARM LAYER AT THE SURFACE (WITH AIR TEMPS IN THE MID 30S)...BUT FALLING BELOW FREEZING ONLY A FEW HUNDRED FEET ALOFT. A WARM NOSE WITH TEMPS TO +2 TO +3 C BEGAN ABOUT ABOUT 2500FT TO 6000FT AGL BEFORE FALLING BELOW FREEZING ABOVE THAT. THE QUICK CHANGE OVER TO FREEZING TEMPS ABOVE THE SURFACE HAS RESULTED IN ELEVATED SURFACE ICING IN HIGHER TERRAIN. THE WARM NOSE WAS SHOWN BY A MORE RECENT 19Z SOUNDING TO BE SLOWLY ERODING AS COLD AIR STUBBORNLY FILTERS IN. THIS EFFECT WAS BEING SHOWN BY DUAL POLAR DOPPLER RADAR. AS OF 320 PM...SNOW HAS FINALLY MADE IT TO THE GREATER HUNTSVILLE AREA...AS THE WARM LAYER MIXES OUT. FOR THE SHORT TERM...HIGH RESOLUTION MODELS FOR THE REMAINDER OF THE AFTERNOON AND EVENING INDICATED A POSSIBLE SNOW BURST EFFECT...AS STRONGER LIFTING AND COOLING ALOFT OCCUR. THIS SYSTEMS MID/UPPER LEVEL LEVEL LOW WILL PASS ACROSS THE AREA. THE RAP AND HIGH RES MODEL OUTPUT WAS SUGGESTING IN THE 2 INCH RANGE VERY POSSIBLE UNDER THE LOW AS IT TRACKS ENE. THIS...ALONG WITH TEMPERATURE VARIANCES MAKES WINTER WEATHER FORECASTING... ESPECIALLY SNOWFALL AMOUNTS A TOUGH CALL. PER THE NAM/GFS APPROX QPF AMOUNTS AND TEMPERATURE FORECASTS...SNOW SHOULD BEGIN STICKING LATE THIS AFTERNOON INTO THE LATE EVENING. TEMPERATURES THIS EVENING WILL REALLY DEPEND ON SNOWFALL. THE PRECIP SHOULD END BY LATE EVENING/EARLY MORNING. WE DO HAVE OVERNIGHT LOW TEMPS FALLING BELOW FREEZING REGION WIDE. THESE READINGS PLUS RESIDUAL MOISTURE ON THE GROUND COULD FREEZE AND PRESENT TRAVEL ISSUES DURING THE OVERNIGHT AND THUR AM. TEMPERATURES SHOULD RISE ABOVE FREEZING BY THE 9/10 AM TIME FRAME. CLOUDS SHOULD DIMINISH EARLY...WITH MORE SUN THAN CLOUDS BY THE LATE MORNING...WITH HIGHS WARMING INTO THE LOW/MID 40S. THESE READINGS MAY BE TOO WARM IF AN AREA GETS AFFECTED BY SIGNIFICANT SNOWFALL. A CLIPPER LIKE SYSTEM WILL BRING A CHANCE FOR MORE RAIN ON FRI... AND A MIX RAIN/SNOW MIX TO THE AREA FRI NIGHT. DRY CONDITIONS ARE EXPECTED FOR THE WEEKEND. GIVEN SHORT TERM ISSUES...HAVE NOT MADE MAJOR CHANGES TO THE EXTENDED. ANOTHER SYSTEM MOVING IN FROM THE WEST SHOULD BRING A SLIGHT CHANCE OF SHOWERS NEXT MON/TUE. TEMPS ABOVE FREEZING SHOULD KEEP THE PRECIP BY THEN AN ALL LIQUID AFFAIR. RSB && .AVIATION... FOR 00Z TAFS...LIFR CONDS IN LGT/MOD SN WILL PERSIST AT BOTH MSL/HSV EARLY THIS TAF PERIOD AS UPPER LOW MOVES NEWD ACROSS THE CENTRAL TENNESSEE VALLEY. BASED ON RADAR TRENDS AND CONSENSUS OF SHORT TERM MODELS EXPECT THREAT FOR SN TO END AT MSL BTWN 13/02-03Z AND AT HSV BY 06Z. ALTHOUGH CIGS/VSBY WILL IMPROVE AS SN ENDS AND WINDS BACK TO NW...STILL EXPECTING CIGS TO REMAIN AROUND 1500 FT THRU AT LEAST 15Z. A BRIEF PERIOD OF VFR CONDS IS EXPECTED DURING THE LATE MORNING/EARLY AFTERNOON HOURS TOMORROW...BEFORE ANOTHER BKN STRATUS DECK BEGINS TO BUILD INTO THE AREA FROM THE NW. SFC WINDS WILL CONTINUE A BACKING TREND TOMORROW AFTN...EVENTUALLY BCMG WSW BY 21Z. 70/DD && .HUN WATCHES/WARNINGS/ADVISORIES... AL...WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR ALZ001>010-016. TN...WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR TNZ076-096-097. && $$ FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WEATHER.GOV/HUNTSVILLE.
Posted on: Wed, 12 Feb 2014 23:49:06 +0000
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