Area Forecast Discussion
Issued by NWS Charleston, WV

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRLX 200913 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 513 AM EDT WED AUG 20 2014 .SYNOPSIS... MUGGY AIRMASS REMAINS IN PLACE WITH ROUNDS OF HEAVY CONVECTION. ONE DISTURBANCE CROSSES FIRST THING THIS MORNING. A WARM FRONT SETS UP TO OUR WEST TONIGHT AND THEN MOVES INTO THE AREA ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... SOLID BAND OF RAIN WITH THUNDERSTORMS ALONG ITS LEADING EDGE ENTERING FCST AREA 07-08Z EARLY THIS MORNING...WILL MAKE FOR A WET MORNING FOR MUCH OF THE AREA...BEFORE EXITING THE CENTRAL APPALACHIANS EARLY THIS AFTERNOON. WIND GUSTS ALONG THE EASTERN EDGE PEAKED AROUND 40 KTS AND NOW APPEAR TO BE 30 KTS OR LESS. RAINFALL IS HARD BUT QUICK HITTING WITH MOST OF THE ONE HALF TO ONE INCH AMOUNTS COMING WITHIN AN HOUR/S TIME. THE FEATURE SHOULD CONTINUE TO WEAKEN WITH TIME...WITH CLOUD TOP WARMING AFTER SUNRISE BREAKING UP THE AREA COVERAGE A BIT. THE FEATURE...AT THE SOUTHERN EDGE OF AN UPPER LEVEL S/W TROUGH CROSSING THE GRETA LAKES AND OHIO VALLEY...WAS NEVER HANDLED WELL BY THE MODELS...WHICH DID KEY IN ON THE CONVECTION MOVING INTO PA MUCH BETTER. THAT CONVECTION GOT CLOSE TO...BUT NEVER REALLY PENETRATED THE NRN PORTION OF THE FCST AREA. CLOUDS WILL BREAK IN THE WAKE OF THE SRN FEATURE THIS AFTERNOON...BUT...LIKE TUE...THIS WILL ONLY ALLOW SCATTERED CONVECTION TO FIRE. THESE CELLS SHOULD BE MOVING FASTER THAN ON TUE...IN THAT 25 KT OR SO SWEET SPOT TOO LOW FOR SEVERE AND TOO HIGH FOR FLOODING. THE NEXT THING IS A WARM FRONT THAT SETS UP NW TO SE OVER THE MIDWEST...PARALLEL TO THE UPPER LEVEL FLOW AROUND A STRENGTHENING RIDGE. NOCTURNAL CONVECTION IS LIKELY TO FORM NE OF THE WARM FRONT UPSTREAM OF THE FCST AREA OVERNIGHT...AND THEN LIKELY BEGIN TO ENCROACH THE AREA FROM THE SW TOWARD DAWN THU. A FOCUSED LOW LEVEL FEED INTO THE WARM FRONT APPEARS TO BE LACKING IN FAVOR OF A MORE UNIFORM 20 KTS...SO THERE WILL LIKELY BE A BROAD AREA OF GENERAL CONVECTION RATHER THAN SOMETHING FOCUSED...HEAVY AND STRONG. GUIDANCE IS HIGHER THAN INHERITED HIGHS BUT MADE NO CHANGE OWING TO ALL THE CLOUDS AND RAIN AROUND THIS MORNING. BLENDED IN A BIAS CORRECTED BLEND ON LOWS TONIGHT FOR LITTLE CHANGE...ANOTHER WARM AND MUGGY ONE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... UNSETTLED WEATHER IN THE SHORT TERM PERIOD. UPPER TROUGH ALONG THE EAST COAST DURING THE PERIOD WITH UPPER RIDGING ACROSS THE MIDWEST...WITH A NORTHWESTERLY FLOW DOMINATING DURING THE PERIOD. SEVERAL UPPER DISTURBANCES IN THE FLOW WILL KEEP THE WEATHER UNSETTLED DURING THE PERIOD...PARTICULARLY THURSDAY NIGHT THROUGH FRIDAY. PW VALUES ARE PROGGED TO PUSH 2 INCHES DURING THIS PERIOD...AND HEAVY RAINFALL IS EXPECTED. IN FACT...THE ENTIRE CWA IS IN A SLIGHT RISK OF EXCESSIVE RAINFALL ON FRIDAY. WILL HIGHLIGHT THE POTENTIAL FOR WATER ISSUES DURING THE PERIOD IN THE HWO. && .LONG TERM /SATURDAY THROUGH TUESDAY/... USED WPC THINKING WITH SOME TWEAKS. NORTHWEST UPPER LEVEL FLOW IS ANTICIPATED THROUGH MUCH OF THE PERIOD...WITH HIGH PRESSURE TRYING TO BUILD IN LATE. AT THE SURFACE...A NW-SE ORIENTED FRONT SHOULD BE LOCATED NEARBY THROUGH MUCH OF THE PERIOD. WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... CLEAR E WITH DENSE VALLY FOG...AS TO THE STRATUS FOG HAT OF TUE MORNING. CLOUD COVER ROLLING IN FROM THE W WILL NIX THE FOG AROUND 08Z CKB AND CRW AND 09-10Z EKN. THE OVERNIGHT INCREASE IN CLOUD IS ON ACCOUNT OF TWO DISTURBANCES MOVING ACROSS THE OHIO VALLEY. ONE MOVING ACROSS THE UPPER OHIO VALLEY AS 06Z APPROACHED MAY IMPACT PKB 09-10Z CKB 11-12Z AND EKN 12-13Z WITH SHOWER AND POSSIBLE THUNDER...ALL THIS GIVEN THE LINE OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE DISTURBANCE EXPANDS SWD OVERNIGHT. SECOND SYSTEM MOVING UP LOWER OHIO VALLEY WILL AFFECT MIDDLE OHIO VALLEY AND THEN CENTRAL APPALACHIANS 12-13Z OHIO RIVER 13-15Z CENTRAL WV AND 16-18Z CENTRAL APPALACHIANS. STRONG TO POSSIBLY DAMAGING WINDS ASSOCIATED WITH THESE STORMS AS 06Z APPROACHED MAY STILL BE STRONG WHEN THE STORMS APPROACH THE OHIO RIVER TOWARD DAWN WED. CONDITIONS WILL IMPROVE TO VFR WED AFTERNOON ONCE THE SECOND BATCH OF CONVECTION ROLLS THROUGH...ALTHOUGH SCATTERED CONVECTION MAY POP LATER WED AFTERNOON...ESPECIALLY E OF THE OHIO RIVER...DRIER AIR ARRIVES W. AREAS OF FOG AND POSSIBLY STRATUS MAY START TO FORM BY 06Z THU...BUT HIGHER CLOUDS ASSOCIATED WITH A WARM FRONT SETTING UP TO THE W MAY STUNT THIS IN THE MIDDLE OHIO VALLEY AFTER 06Z THU. SFC FLOW WILL BE LIGHT SW EXCEPT POSSIBLE STRONG GUSTS FROM THE W TO NW IN THUNDERSTORMS. LIGHT W FLOW ALOFT MAY STRENGTHEN A BIT WED EVENING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: FOG WILL VARY IN INTENSITY OVERNIGHT AND TIMING OF ITS DISSIPATION WILL VARY. TIMING AND IMPACT OF SHOWERS AND THUNDERSTORMS OVERNIGHT INTO WED 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 08/20/14 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY L L L M M M M M H M M M HTS CONSISTENCY M M M H H H H M M M M M BKW CONSISTENCY H H H L L M M H H M M M EKN CONSISTENCY L L L L L M M M H M M M PKB CONSISTENCY M M M H H H H H M M M M CKB CONSISTENCY M M M H H H H M M M M M AFTER 06Z THURSDAY... IN THE HUMID ENVIRONMENT...IFR EASILY POSSIBLE IN ANY ROUND OF CONVECTION WED NT THROUGH FRI NT. LATE NIGHT AND EARLY MORNING POST RAIN FOG AND STRATUS ALSO POSSIBLE THROUGH SAT MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM SHORT TERM...SL LONG TERM...JSH AVIATION...TRM

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.