Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 010832 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 430 AM EDT WED OCT 1 2014 .SYNOPSIS... WEAK HIGH PRESSURE/WEAK FLOW TODAY INTO EARLY THURSDAY. STRONG COLD FRONT STREAKS ACROSS FRIDAY AFTERNOON AND EVENING. MUCH COOLER AIR ARRIVES FOR WEEKEND. REINFORCING FRONT MAY ARRIVE EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... WHEN YOU GET DOWN TO THE DETAILS...IT IS NEVER EASY. THE 88D VAD WIND PROFILES SINCE START OF GRAVEYARD SHIFT...03Z...HAVE BEEN SHOWING STRONGER NE FLOW AT 925 MB THAN ANY MODEL I HAVE LOOKED AT. IT WAS NEAR 20 KNOTS...ABOUT 15 KNOTS AT 08Z. THE EXPECTED STRATUS WE TALKED ABOUT YESTERDAY...ID FORM...AND IS STILL MOVING SW AND STILL PENETRATING FURTHER S INTO EASTERN KENTUCKY. DESPITE THE THIN NATURE OF THIS MOISTURE...WE ARE STILL TRYING TO HOLD ONTO PLENTY OF CLOUDS THIS MORNING ACROSS THE LOWLANDS...THE ONE EXCEPTION MAY BE THE HEADWATERS OF THE GUYANDOTTE AND TUG FORK. FURTHER EAST AND SOUTHEAST...WAS NOT HITTING THE LOWER STRATUS AS HARD IN THE MOUNTAIN COUNTIES AND UPPER GREENBRIER VALLEY. WHERE THE STRATUS FORMED...WAS NOT EXPECTING DENSE FOG. AREAS THAT GOT MORE RAIN TUESDAY AFTERNOON AND EVENING ARE THE EXCEPTION...WITH MORE FOG FOR PREDAWN AND DAWN...SUCH AS AROUND CLARKSBURG. TRIED TO SLOW DOWN THE DIURNAL RISE IN TEMPERATURE DURING THE 12Z TO 15Z TIME FRAME...JUST A BIT...FOR AREAS IN THE MID OHIO VALLEY AROUND MARIETTA AND PARKERSBURG...WITH HIGHER CONFIDENCE IN CLOUDS HOLDING THERE. SOME 5 TO 6 MILES IN HAZE MAY LINGER TOO. STILL TRY TO BREAK UP THE LEFTOVER STRATUS THIS AFTERNOON. LEFT A 20 POP OVER THE CENTRAL MOUNTAIN COUNTIES THROUGH THE AFTERNOON. IN WHAT FLOW THERE IS...A CONFLUENT PATTERN WITH WEAK WESTERLIES W OF MOUNTAINS...AND EASTERLIES STILL E IN VIRGINIA. JUST PLAYING UP MORE OF THE DIURNAL FOG OVERNIGHT TONIGHT. THE LONGER THE CLOUDS HOLD TODAY...THE SOONER IT FORMS DURING THE NIGHT. THOUGHT SOME OF THE MOS GUIDANCE WAS A BIT COLD TONIGHT...SUCH AS THE 43 DEGREES ON BOTH THE GFS AND NAM MOS FOR ELKINS. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... MAIN SYNOPTIC FEATURE FOR THE SHORT TERM IS A DECENT COLD FRONT WHICH WILL MOVE THROUGH FRIDAY INTO FRIDAY NIGHT...AND RELATED UPPER LEVEL TROUGH DIGGING IN BEHIND IT. THE COLD FRONT IS ASSOCIATED WITH A DEEPENING SURFACE LOW MOVING THROUGH THE WESTERN GREAT LAKES FRIDAY. SOME DISCREPANCIES ON TIMING BETWEEN THE MODELS...THE CMC IS THE FASTEST...AND APPEARS TO FAST. THE GFS AND ECMWF ARE FAIRLY SIMILAR...WITH THE NAM LAGGING BEHIND. WENT MAINLY WITH A GFS/ECMWF BLEND WHICH DID NOT CHANGE MUCH FROM THE PREVIOUS FORECAST. HAVE AN AREA OF LIKELY POPS AHEAD OF THE FRONT. FLOW IS PRETTY FAST...SO EXPECT INDIVIDUAL CELLS TO BE FAST MOVING. THERE IS NOT A WHOLE LOT OF INSTABILITY...BUT STILL HAVE GOOD FORCING WITH THE FRONT. SO HAVE DECENT CHANCES OF THUNDER FRIDAY AFTERNOON AND EVENING. WITH MARGINAL INSTABILITY...AND THE BEST SHEAR LAGGING WELL BEHIND...AGREE WITH SPC ANALYSIS THAT SEVERE STORMS ARE NOT ALL THAT LIKELY. BUT WITH THE FAST MOVEMENT...ANY OUTFLOW WILL ALREADY HAVE A DECENT SYNOPTIC VELOCITY TO FEED OFF OF. ANTICIPATING AN SPS COULD BE NEEDED FOR STRONGER CELLS...WILL INCLUDE GUSTY OUTFLOW MENTION IN HWO. WITH THE UPPER LEVEL TROUGH CROSSING SATURDAY...HAVE SLIGHT CHANCE POP ACROSS THE NORTHERN CWA. PROBABLY COULD HAVE INCREASED TO CHANCE BASED ON MODELS SHOWING GOOD UPPER LEVEL FORCING...HOWEVER MOISTURE WILL BE VERY LIMITED BEHIND THE COLD FRONT. FOR HIGHS AND LOWS...BLENDED IN MET GUIDANCE THURSDAY THROUGH FRIDAY THEN TRANSITIONED TO A WPC/BIAS-CORRECTED CONSENSUS BLEND IN THE VERY COOL AIR BEHIND THE FRONT. HAVE HIGHS ON SATURDAY STRUGGLING TO REACH 60. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... THE AREA DOES REMAIN IN THE BAROCLINIC ZONE MUCH OF THE PERIOD AS THE SWD EXTENT OF THE L/W DOES RETREAT. THIS MAKES IT DIFFICULT TO TIME THE COOLEST WEATHER OTHER THAN THE INITIAL SHOT SAT NT...WHICH IS NOW CODED UP AS THE COOLEST PART OF THE FCST. THIS INCLUDES POTENTIALLY FROSTY TEMPERATURES FOR THE NRN WV MOUNTAINS AND IN SE OH COME SUN MORNING. THE NEXT REINFORCING S/W TROUGH BRINGS THE CHANCE FOR SHOWERS SOMETIME EARLY NEXT WEEK...WITH MODEL DIFFERENCES AS TO ITS TIMING ALONG WITH TIMING THE ARRIVAL OF THE REINFORCING COOL AIR BEHIND IT SO COULD NOT REALLY DEPICT NEXT COOL DOWN EVEN ON DAY 7 NT. BLENDED IN WPC AND THE LOW MEX FOR LOWS SAT NT...AGAIN ON LOW END OF GUIDANCE. WILL NOT HWO FROST DAY 4 NT THOUGH PENDING HOW FAVORABLE SAT NT TURNS OUT FOR RADIATIVE COOLING. BLENDED IN WPC TEMPERATURES FOR THE LESS CERTAIN BALANCE OF THE EXTENDED. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... THE EXPECTED STRATUS IS FORMING IN THE OHIO VALLEY AND SINKING SW ON THE NE LOW LEVEL FLOW. YET...THAT FLOW BREAKS DOWN AFTER 09Z. WILL CONTINUE TO HIGHLIGHT CEILINGS ON EITHER SIDE OF 1 THSD FT BKN/OVC FOR THE OHIO VALLEY COUNTIES...BUT CONFIDENCE LOWERS ON WHETHER IT CAN PUSH INTO CKB TO CRW. VAD WINDS ON KRLX 05 TO 06Z WERE STILL NE AT 15 TO 20 KNOTS AT 925 MBS WHICH IS STRONGER THAN MOST MODELS. SO WILL TRY TO FORM STRATUS AND NOT THICK FOG AT CKB TO CRW. WAS NOT FORECASTING THE LOW STRATUS CEILING TO REACH EKN TO BKW CORRIDOR. STILL EXPECT THE THIN STRATUS TO BE STUBBORN TO ERODE/LIFT WEDNESDAY ESPECIALLY IN THE MID OHIO VALLEY COUNTIES NEAR PKB. 18Z IS NOT OUT OF THE QUESTION FOR THE IFR/MVFR CONDITIONS. A FEW SPOTTY SHOWERS STILL POSSIBLE THROUGH AFTERNOON OVER THE WEST VIRGINIA CENTRAL MOUNTAIN COUNTIES. HAVE MOSTLY SCATTERED CLOUDS BY 00Z THURSDAY. DIURNAL FOG MAY BE FORMING FIRST...03Z TO 06Z THURSDAY...IN THE MOUNTAIN VALLEYS AROUND CRW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: EXTENT OF STRATUS...AND THE 1000FT THRESHOLD ARE IN QUESTION FOR THE 08Z TO 13Z TIME FRAME. TIMING THE LIFTING AND BREAK UP OF THE THIN STRATUS MAY VARY. 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 WED 10/01/14 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY H M M H H H H M M M M M HTS CONSISTENCY H H H H H H H M M M M M BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H M M M M M M PKB CONSISTENCY H H H H H H M M M M M M CKB CONSISTENCY L L L L L H H H M M M M AFTER 06Z THURSDAY... BRIEF IFR POSSIBLE IN FAST MOVING SHOWERS AND/OR THUNDERSTORMS FRIDAY INTO FRIDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...TRM AVIATION...KTB

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