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000 FXUS62 KTAE 010711 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 310 AM EDT SAT NOV 01 2008 .SYNOPSIS... LOOKING AT THE 07Z WATER VAPOR AND H4 RUC ANALYSIS ACROSS NORTH AMERICA WE FIND A RATHER UNEVENTFUL PATTERN FOR THE TIME BEING. FROM WEST TO EAST THE NORTHERN STREAM FLOW IS RIDING UP AND OVER ILL-DEFINED RIDGING ACROSS THE EASTERN ROCKIES AND CENTRAL PLAINS... THEN DIPS DOWN INTO THE NORTHERN GREAT LAKES AND EASTWARD TO THE CANADIAN MARITIMES AROUND THE SOUTHERN PERIPHERY OF THE POLAR VORTEX SPINNING TO THE EAST OF JAMES BAY IN CANADA. A SEPARATE PIECE OF FAIRLY POTENT SHORTWAVE ENERGY IS DROPPING SOUTHEASTWARD ACROSS THE SOUTHERN MS VALLEY ON THE EASTERN PERIPHERY OF THE CENTRAL PLAINS RIDGE. AT THE SURFACE...RIDGE AXIS REMAINS TO OUR NORTH FROM THE CAROLINAS TO NORTHERN/CENTRAL GA AND AL. THIS PUTS OUR AREA IN NORTHEAST FLOW ALONG THE SOUTHERN EDGE OF THE HIGH. MOSTLY CLEAR SKIES STILL SEEN ACROSS MOST OF THE AREA WITH DRY LOW LEVEL AIR (DEWPOINTS IN THE 30S/40S) IN PLACE. HOWEVER...BEGINNING TO SEE LOWER LEVEL MOISTURE/CLOUDS INCREASE TO OUR EAST AND SOUTHEAST AS THE NORTHEAST FLOW BRINGS ATLANTIC MOISTURE INTO SOUTHEAST GA AND ACROSS THE NORTHERN FL PENINSULA. && .SHORT TERM (SATURDAY THROUGH MONDAY)... TODAY...MID-LEVEL SHORTWAVE ENERGY APPROACHING THE NORTH-CENTRAL GULF COAST FROM THE SOUTHERN MS VALLEY IS FORECAST TO CLOSE OFF THROUGH THE DAY AS IT DRIFTS INTO THE NORTHEAST GULF OF MEXICO. AT THE SURFACE WE WILL SEE LITTLE CHANGE IN PATTERN THROUGH THE DAY AS THE RIDGE TO OUR NORTH HOLDS IN PLACE KEEPING A LIGHT NORTHEAST FLOW GOING ACROSS THE AREA. SKIES OVER THE SOUTHEAST HALF OF THE AREA WILL BECOME A MIX OF LOW LEVEL CLOUDS AND SUN TODAY AS THE NORTHEAST FLOW BRINGS INCREASING ATLANTIC MOISTURE TO AN AREA GENERALLY SOUTH OF A LINE FROM VALDOSTA TO TALLAHASSEE AND PANAMA CITY. SOME INCREASE IN MID/UPPER LEVEL MOISTURE IS LIKELY ACROSS THE WESTERN ZONES... ESPECIALLY LATE THIS AFTERNOON AS DEEP LAYER SYNOPTIC LIFT ON THE EASTERN SIDE OF THE UPPER LOW SPREADS EASTWARD. TONIGHT...UPPER LOW TAKES UP RESIDENCE OVER AND TO THE SW OF THE REGION TONIGHT. SYNOPTIC LIFT DRIVEN BY DECENT MID-LEVEL Q-VECTOR CONVERGENCE SPREADS EAST TO COVER EVEN OUR EASTERN ZONES BY THE LATE NIGHT HOURS. GFS HAS BEEN VERY CONSISTENT FOR SEVERAL RUNS SHOWING DECENT LOWER AND MID-LEVEL ISENTROPIC UPGLIDE TAKING SHAPE ACROSS THE NORTH-CENTRAL FL PENINSULA AND OUR EASTERN MARINE ZONES BY EARLY SUNDAY MORNING AS WELL. WHILE THE LOW LEVEL AIRMASS WILL REMAIN MUCH TO DRY ACROSS MUCH OF GA/SE AL/AND THE FL PANHANDLE TO SUPPORT ANYTHING MORE THAN A FEW POSSIBLE SPRINKLES REACHING THE SURFACE... OVER THE EASTERN FL BIG BEND AND OUR MARINE ZONES THE LOW LEVELS WILL BE MORE PRIMED BY THE ADVECTED ATLANTIC MOISTURE TO SUPPORT AN INCREASING CHANCE OF SHOWERS/AREAS OF LIGHT RAIN BEFORE SUNRISE. SUNDAY...VERY SLOW EVOLUTION TO THIS UPPER LEVEL SYSTEM THROUGH THE DAY SUNDAY. WILL SEE SKIES BECOME MOSTLY CLOUDY TO CLOUDY OVER MOST OF THE AREA BY THE AFTERNOON HOURS AS UPPER LOW PULLS JUST A BIT FURTHER EAST. AS THIS OCCURS THE BEST SYNOPTIC LIFT ASSOCIATED WITH IT WILL BEGIN TO EXIT THE WESTERN FORECAST AREA LATE IN THE DAY. AT THE SAME TIME...STRONG HIGH PRESSURE DROPPING SOUTHEAST TO NEW ENGLAND WILL ACT TO RE-ENFORCE THE RIDGING ALONG THE ENTIRE EAST COAST. ONCE AGAIN OUTSIDE OF A FEW SPRINKLES...AREAS NORTH AND WEST OF A LINE FROM PANAMA CITY TO TALLAHASSEE AND VALDOSTA SHOULD REMAIN ON THE DRY SIDE WITH ONLY A SLIGHT CHANCE POP AS THE DRY LOW LEVEL AIR KEEPS ANY SIGNIFICANT PRECIP AT BAY. FURTHER SOUTH AND EAST THE BETTER DYNAMICS FOR LIFT AND MOISTURE WILL KEEP THE CHANCES FOR SHOWERS/AREAS OF LIGHTER RAIN IN THE FORECAST. LATEST GFS PLOTS ACTUALLY SHOWING THE SHOWALTER INDEX DROPPING TO AROUND ZERO ON SUNDAY ACROSS THE MARINE ZONES AND SOUTHEAST BIG BEND...SO MAY DEVELOP JUST ENOUGH INSTABILITY ABOVE THE SURFACE TO SUPPORT AN ISOLATED RUMBLE OF THUNDER OVER THESE ZONES. AS THE UPPER LOW ATTEMPTS TO PRECIPITATE INTO THE DRIER LOW LEVELS AROUND TALLAHASSEE AND VALDOSTA...MAY END UP WITH A RATHER COOL AFTERNOON AS HIGH TEMPERATURES STRUGGLE TO REACH" onClick="return popup(this, 'notes')">REACH THE UPPER 60S. SUNDAY NIGHT/MONDAY...UPPER LEVEL LOW CONTINUES TO SLOWLY PULL EAST AND NORTHEAST SUNDAY NIGHT THROUGH MONDAY. BEST SYNOPTIC LIFT ON THE EASTERN SIDE WEAKENS AND EXITS THE AREA BY MONDAY MORNING. AS THE MID-LEVEL ENERGY REACHES THE SOUTHEAST COAST...GFS INDICATING A SHARPENING OF A SURFACE TROUGH OFF THE NORTHEAST FL/GEORGIA COAST WITH THE POTENTIAL FOR A CLOSE LOW FEATURE AT THE SURFACE TO DEVELOP BY MONDAY AFTERNOON. THIS WOULD ACT TO BACK OUR LOW LEVEL FLOW TO A MORE NORTHERLY AND DRIER DIRECTION. THE LATEST 00Z GFS IS LIKELY AN EXTREME SOLUTION OF THIS BACKING...HOWEVER IT DOESN`T NEED TO BE THIS RADICAL TO HAVE A SIGNIFICANT IMPACT. THEREFORE WITH SOME DRYING AT THE SURFACE AND THE LOSS OF SYNOPTIC LIFT/UPGLIDE...WILL TAPER POPS BACK TO ONLY ALONG THE SUWANNEE RIVER VALLEY/I-75 CORRIDOR BY THE AFTERNOON HOURS. && .LONG TERM...(TUESDAY THROUGH SATURDAY)... WITH BOTH THE GFS AND ECMWF NOW IN GOOD AGREEMENT THAT MOST OF THE LINGERING DEEP LAYER MOISTURE AND UPPER LEVEL SUPPORT WILL BE PULLING OUT OF THE CWA BY LATE ON MONDAY...SHOULD BE ABLE TO ACCELERATE THE ENDING OF POPS OVER THE REGION BY A FULL 12-24 HRS. THIS SHOULD ALLOW MONDAY NIGHT AND TUESDAY TO BE ESSENTIALLY DRY ACROSS THE AREA...WITH WEAK SFC RIDGING HOLDING IN BEHIND THE UPPER LOW FOR WED AND THU. IN ADDITION ...A PERIOD OF UPPER LEVEL RIDGING IS EXPECTED TO BUILD IN OVER THE SE U.S. ON WED AND THU WHICH SHOULD ALLOW HIGH TEMPS TO CLIMB BACK ABOVE CLIMO LEVELS...WITH 80 DEGREE MAXES NOT OUT OF THE QUESTION. THE NEXT CHANCE OF RAIN OVER THE AREA IS NOT EXPECTED UNTIL FRIDAY ...AS A STRONG UPPER LEVEL LOW TRAVERSES THE NORTHERN TIER OF THE U.S. ALLOWING A FAIRLY SHARP TROF TO HELP PUSH A SFC COLD FRONT THROUGH THE REGION. IT IS THIS LATTER TIME PERIOD WHERE THERE ARE SOME SIGNIFICANT DIFFERENCES BETWEEN THE ECMWF AND GFS...WITH THE ECMWF THE MOST CONSISTENT RUN TO RUN IN PUSHING THE COLD FRONT THROUGH ON FRIDAY. THE GFS WAS IN AGREEMENT WITH THE EURO ON LAST NIGHT`S 00 UTC RUN...BUT ITS 12 AND 18 UTC RUNS SLOWED CONSIDERABLY ONLY TO SEE TONIGHT`S 00 UTC RUN COME IN SLIGHTLY FASTER ONCE AGAIN WITH THE FRONTAL PASSAGE FRI NIGHT AD SAT MORNING. THIS RUN IS STILL SLOWER THAN THE LAST 2 ECMWF RUNS...SO WILL LEAN TOWARDS THE EURO THIS PACKAGE. THIS WILL HAVE IMPLICATIONS ON POPS (FRI-FRI NIGHT) AND TEMPS (BOTH LOWS AND HIGHS ON SAT)...BOTH OF WHICH WILL BE ADJUSTED DOWNWARD FROM THE GFS AND MEX GUIDANCE. && .MARINE... SURFACE RIDGE AXIS WILL REMAIN PARKED TO THE NORTH OF THE FORECAST WATERS THROUGH SUNDAY KEEPING A NORTHEASTERLY FLOW GOING. AT THE SAME TIME AN UPPER LEVEL SYSTEM WILL APPROACH AND SLOWLY CROSS OVER THE AREA INCREASING THE CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS STARTING AFTER MIDNIGHT TONIGHT. EXPECTING WINDS GENERALLY BETWEEN 10 AND 15 KNOTS THROUGH THE DAY OUT OF THE NORTHEAST WITH SEAS 2 TO 4 FEET. WINDS ARE EXPECTED TO INCREASE A BIT TO CAUTIONARY LEVELS TONIGHT THROUGH SUNDAY NIGHT. WINDS AND SEAS WILL THEN BEGIN TO DIMINISH INTO THE MIDDLE PART OF NEXT WEEK AS THE SURFACE RIDGE TO OUR NORTH BUILDS SOUTH ACROSS THE FORECAST WATERS. && .AVIATION... ANOTHER BAND OF LOW-MID LEVEL CLOUDS HAS FORMED ACROSS NE FL EARLY THIS MORNING...AND IT IS BEING PUSHED W-SW BY E-NE FLOW FROM THE THE SFC RIDGE OVER THE CAROLINAS. THE LEADING WESTERN EDGE OF THIS CLOUDINESS IS ERODING SOMEWHAT IN THE DRIER AIR...BUT DO EXPECT SCT-BKN CIGS TO MOVE INTO EASTERN PORTIONS OF THE CWA OVERNIGHT... WHICH WILL SHOULD IMPACT VLD FIRST AND THEN TLH 2-3 HRS LATER. EXPECT THESE CIGS TO BE GENERALLY VFR WITH SC IN THE 3-4 KFT RANGE AND AC IN THE 8-9 KFT AREA...BUT CANNOT RULE OUT A BRIEF PERIOD OF MVFR LEVELS AT VLD...AS SOME LOWER SKIES ARE NOW AFFECTING COASTAL AREAS OF NE FL AND SE GA. FOR THE DAYLIGHT HOURS...EXPECT VFR CONDITIONS TO PREVAIL AT ALL OF THE TAF SITES WITH GENERALLY SCT CU AND AC OVER EASTERN AREAS...WITH A PERIOD OF BKN CIGS STILL POSSIBLE AT VLD IN THE AFTERNOON. && .FIRE WEATHER... ...COMING SOON... && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 73 49 68 55 74 / 0 10 30 30 20 PANAMA CITY 74 51 72 56 74 / 0 10 30 20 10 DOTHAN 73 45 72 51 73 / 0 0 10 10 10 ALBANY 73 45 72 52 73 / 0 0 10 20 10 VALDOSTA 72 50 68 55 72 / 10 15 45 50 30 CROSS CITY 74 54 72 56 75 / 10 20 50 50 30 && .TAE WATCHES/WARNINGS/ADVISORIES... ...COMING SOON... && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA AVIATION/LONG TERM/FIRE WX...GOULD