Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 160844 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 344 AM EST TUE DEC 16 2014 .SYNOPSIS...
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COLD FRONT TODAY. HIGH PRESSURE THURSDAY INTO FRIDAY. LOW PRESSURE APPROACHES FOR THE WEEKEND.
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&& .NEAR TERM /THROUGH TONIGHT/...
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ONLY MAKING FINESSE TYPE CHANGES TO THE POPS OVER THE NEXT FEW HOURS WITH BANDS OF SHOWERS ARRIVING FROM THE SOUTHWEST AND OVERALL COVERAGE ON THE SLOW INCREASE. COLD FRONT STILL BACK IN IN/KY/TN/AL AT THIS HOUR AND EXPECTING PASSAGE AFTER DAWN AND THROUGH THE MOUNTAINS BY 18Z TODAY. BEHIND THE FRONT...WINDS INCREASE OUT OF THE WEST SOUTHWEST GUSTING TO THE 20KT RANGE. WRAP AROUND MOISTURE KEEPS LOW LEVEL CLOUD COVER IN PLACE WITH THE POTENTIAL FOR SHOWERS INTO THE OVERNIGHT. 850MB TEMPERATURES DO NOT GET INTO THE AUTO CONVECT RANGE HOWEVER SINCE THE SYSTEM IS PACIFIC IN NATURE...SO WILL TAKE POPS OUT OF THE LOWLANDS BY 12Z WEDNESDAY. PREVIOUS FORECAST WAS CARRYING DRIZZLE OVER CONVECTIVE PRECIPITATION...BUT THINK THE MOISTURE DEPTH WILL BE SUFFICIENT ENOUGH TO GET SHOWERS/LATE SNOW SHOWERS IN THE MOUNTAINS. BY THE TIME PRECIPITATION CHANGES OVER IN THE MOUNTAINS...POPS SHOULD BE LOW ENOUGH THAT SNOW ACCUMULATIONS WILL BE PRETTY UNLIKELY. ADDED A DEGREE OR TWO TO THE MAX TEMPERATURES TODAY OVER THE WEST VIRGINIA LOWLANDS WITH FEW CHANGES TO THE MIN TEMPERATURES TONIGHT. ONLY HAVE THE MOUNTAINS DROPPING BELOW FREEZING FOR THIS FORECAST.
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&& .SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
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COMPLICATED SPLIT FLOW PATTERN ALOFT CONTINUES...WITH AN ACTIVE SOUTHERN STREAM TO THE SOUTH OF A BLOCKING PATTERN ACROSS CANADA. LINGERING MOUNTAIN SNOW SHOWERS END BY WEDNESDAY AFTERNOON AS ONE SYSTEM EXITS AND CANADIAN HIGH PRESSURE BUILDS IN. THIS HIGH PRESSURE SYSTEM WILL BRING MOSTLY DRY WEATHER AND NEAR SEASONABLE TEMPERATURES THURSDAY AND FRIDAY. ALTHOUGH CLOUDS MAY INCREASE THURSDAY FROM THE NEXT SOUTHERN STREAM SYSTEM...THE MODELS CONTINUE TO KEEP THIS SYSTEM RATHER FLAT AND ITS PRECIPITATION SHIELD TO OUR SOUTH.
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&& .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
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BY THE END OF THE WORK WEEK...ALL THE MODELS HAVE A MAJOR SOUTHERN STREAM SYSTEM COMING OUT OF THE SOUTHERN PLAINS. WHILE ALL AGREE THIS WILL BE A HIGHER AMPLITUDE SYSTEM THAN THE PREVIOUS AND BEGIN TO AFFECT US FRIDAY NIGHT...THERE ARE MODEL DIFFERENCES IN HOW THIS SYSTEM EVOLVES AND THE TRACK IT TAKES OVER THE WEEKEND. ALL THIS HAS TO DO WITH THE BLOCKY PATTERN ACROSS CANADA. CONSIDERING THE OPERATIONAL MODELS...THE EURO IS THE OUTLIER MODEL IN KEEPING THE CANADIAN BLOCK SUCH THAT THIS APPROACHING SYSTEM TAKES A MORE SOUTHERN ROUTE...WITH THE PARENT LOW PRESSURE SYSTEM TRACKING WELL SOUTH AND EAST OF US. THIS KEEPS ENOUGH COLD AIR FOR THE PRECIPITATION TO BE AT LEAST A WINTRY MIX. THE UKMET...CMC AND GFS MODELS ARE RATHER SIMILAR IN BREAKING DOWN THE CANADIAN BLOCK ENOUGH TO ALLOW A WEAKENING PARENT LOW TO TRACK UP JUST WEST OF THE MOUNTAINS SATURDAY BEFORE REGENERATING ALONG THE EAST COAST...BUT WITH THE GFS LOOKING TO BE A BIT TOO WARM. THE PREFERRED MODEL CONSENSUS...WITH A SLIGHTLY COOLER VERSION OF THE GFS...WILL ALLOW A WINTRY MIX AT THE BEGINNING FOR FRIDAY NIGHT. THE PRECIPITATION WILL TREND TO MOSTLY RAIN OVER MUCH OF THE LOW LANDS SATURDAY...BEFORE CHANGING BACK TO A WINTRY MIX AND THEN SNOW SATURDAY NIGHT INTO SUNDAY MORNING AS COLDER AIR RUSHES BACK IN. AT THIS DISTANT TIME FRAME...AND GIVEN THE CHANGES THAT CAN OCCUR IN THIS COMPLICATED SPLIT FLOW PATTERN...WILL ONLY MENTION THE POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK FOR THE WEEKEND STORM. IN ANY CASE...LOOK FOR TEMPERATURES TO BE NEAR SEASONABLE LEVELS.
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&& .AVIATION /08Z TUESDAY THROUGH SATURDAY/...
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PREFRONTAL SHOWERS BEGINNING TO FILL THE MIDDLE OHIO VALLEY WITH COVERAGE EXPECTED TO GET MORE NUMEROUS THROUGH THE OVERNIGHT. GENERALLY HAVE MVFR CEILINGS COMING INTO PLAY WITH INTERMITTENT MVFR VISIBILITIES IN SHOWERS. NOT EXPECTING IFR WITH THESE SHOWERS AS THE INTENSITY SHOULD NOT BE SUCH TO WARRANT THIS. POST FRONTAL WINDS COME OUT OF THE WEST SOUTHWEST AND INCREASE TO 20KTS WITH SHOWERS ENDING AFTER 18Z...AND EARLIER FOR THE WESTERN TERMINALS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS: BRIEF IFR CANNOT BE DISCOUNTED. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE 12/16/14 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 CRW CONSISTENCY H M M M M M M H H H H H HTS CONSISTENCY H M M M M L M M M M M M BKW CONSISTENCY H M H H H H H M M M H H EKN CONSISTENCY H H H M H H H H H H M H PKB CONSISTENCY H H H H H M M M M M M M CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z WEDNESDAY... IFR POSSIBLE IN CLOUDS DRIZZLE/FREEZING DRIZZLE IN THE MOUNTAINS TUESDAY NIGHT INTO WEDNESDAY MORNING.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JMV/26 NEAR TERM...26 SHORT TERM...JMV LONG TERM...MZ/JMV AVIATION...26

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