Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 251853 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 253 PM EDT FRI JUL 25 2014 .SYNOPSIS...
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FLOW TURNS SOUTHWEST BRINGING STRONG WARM AIR ADVECTION SATURDAY. A SERIES OF DISTURBANCES IN A WEST/NORTHWEST FLOW ALOFT WITH ROUNDS OF CONVECTION MAINLY SATURDAY NIGHT THRU SUNDAY NIGHT.
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&& .NEAR TERM /THROUGH SATURDAY/...
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LITTLE CHANGE FROM PREV FCST...WITH ONLY A FEW MINOR ADJUSTMENTS PER LATEST DATA. A S/W MOVES THROUGH THE MEAN NW FLOW BUT WITH MEAGER LLVL MOISTURE AND A STOUT INVERSION AT ABOUT 800MB...KEEPING THE FORECAST DRY THOUGH IT MAY BE THEORETICALLY POSSIBLE TO SEE A CONVECTIVE SPRINKLE OVER THE EASTERN HIGH PEAKS WITH A CONVECTIVE LAYER DEPTH OF 3KFT. ELSEWHERE...MOSTLY CLEAR TO OCCASIONAL PARTLY CLOUDY SKIES WITH MINS TEMPS A DEGREE OR TWO EITHER SIDE OF 60F FOR THE LOWLANDS. ON THE BROADER SCALE...AN UPPER LEVEL SYSTEM AND ASSOC SFC LOW WILL DRAG A WARM FRONT MAINLY TO OUR NORTH AND WEST...WITH SFC HIGH PRESSURE MOVING OFF THE MID-ATLANTIC SEABOARD. BY SATURDAY THE AFOREMENTIONED WARM FRONT BYPASSES US TO THE NORTH WITH OUR AREA SQUARELY IN THE WARM SECTOR. AGREE WITH PREV FCST THAT SYNOPTICALLY-SPEAKING...OUR AREA SHOULD BY AND LARGE REMAIN DRY DURING THE DAY SATURDAY WITH THE BEST MOISTURE AND LIFT NORTH AND EAST. HOWEVER...WHILE A MUCH STRONGER VORT MAX RESIDES FURTHER WEST...A WEAK RIPPLE IS PROGGED TO MOVE OUT OF THE SW GREAT LAKES TOWARDS NW OHIO BY 18Z SAT...WHICH WOULD MOVE E/SE TOWARDS THE NORTHWEST ZONES. WILL MAINTAIN SLIGHT/LOW CHANCE POPS TO ACCOUNT FOR THIS POSSIBILITY. BETTER POTENTIAL FOR SEVERE STORMS IS FURTHER NORTHWEST OVER CENTRAL AND WESTERN OH...BUT ENOUGH INSTABILITY WILL BE PRESENT THAT A SEVERE STORM WILL BE POSSIBLE MAINLY OVER OUR SE OHIO ZONES DURING THE LATE AFTERNOON/EARLY EVE HOURS.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
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SURFACE SOUTHERLY FLOW AND WESTERLY ALOFT WILL BRING MODEST WARM AIR ADVECTION TO THE REGION SATURDAY NIGHT INTO SUNDAY. WINDS AT H85 BECOME ABOUT 45 KNOTS OUT OF THE SOUTHWEST AHEAD OF AN APPROACHING COLD FRONT. A BROAD UPPER LEVEL LOW PRESSURE SYSTEM CENTERED NORTH OF THE GREAT LAKES REGION EXTENDS SOUTH WITH A SERIES OF VORTICITY LOBES NOTICED AT H5 PASSING OVER OH VALLEY AND WV. THE FIRST AND WEAKER WAVE MOVES THROUGH OVERNIGHT HOURS OF SATURDAY NIGHT. THE SECOND BUT STRONGER VORTICITY MAXIMA MOVES ACROSS DURING THE DAY SUNDAY WITH ADDITIONAL VORTICITY LOBES PASSING THROUGH MONDAY. MODELS ARE IN DESCENT AGREEMENT WITH THE TIMING OF CONVECTION REACHING OR DEVELOPING OVER OUR AREA...ALTHOUGH SUBTLE DIFFERENCES ARE NOTICED ON THE LOCATION OF THE STRONGEST PCPN. THE GFS AND ECMWF SHOW THE ARRIVAL OF TWO MID LEVEL WAVES...ONE APPROACHING SOUTHEAST OH BY 00Z AND THE SECOND BY 06Z SUNDAY. SFC BASED CAPE INCREASES TO 1800 J/KG BY 12Z SUNDAY...AND EXCEEDING 2500 J/KG SUNDAY AFTERNOON ACROSS THE TRI STATE AREA...EXTENDING NORTHEAST ACROSS WV AND SOUTHEAST OH. MODELS SUGGEST DEEP LAYERED SHEAR EXCEEDING 60 KNOTS AND PWATS AROUND 2 INCHES SUNDAY AFTERNOON. HELICITY VALUES EXCEED 300 M2/S2 BY THE SAME TIME PERIOD. THESE INGREDIENT ARE FAVORABLE FOR STORMS TO BECOME SEVERE WITH THERMODYNAMIC AND DYNAMIC INSTABILITY. CONSEQUENTLY...THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS ACROSS SOUTHEAST OH...NORTHEAST KY AND ALL OF WV FOR SUNDAY. WITH GOOD CONSENSUS AMONG SYNOPTIC MODELS AND SREF INDICATING 60 PERCENT POPS MAINLY ACROSS THE NORTHERN THIRD OF OUR CWA...CONFIDENCE HAS INCREASED AND DECIDED TO INCREASE POPS AS WELL FOR SUNDAY. MENTIONED DAMAGING WINDS AND HAIL IN THE WEATHER GRIDS ALONG WITH HEAVY RAIN PER THE AFOREMENTIONED PARAMETERS. IN ADDITION...HPC HAVE PORTIONS OF SOUTHEAST OH...NORTHEAST KY AND THE ENTIRE AREA OF WV UNDER HIGH PROBABILITY OF EXCESSIVE RAINFALL. BACKWARD CORFIDI VECTOR MAGNITUDE INCREASE CONSIDERABLY ON SUNDAY AFTERNOON. WITH PWATS RANGING AROUND 2 INCHES...AND THE NATURE OF THE SEVERE THUNDERSTORMS...WATER PROBLEMS MAY RESULT WITH REPETITIVE PERIODS OF HEAVY RAINFALL. A FLASH FLOOD WATCH MAY BE REQUIRED FOR SUNDAY AND EARLY MONDAY. LINGERING SHOWERS OR STORMS CAN NOT BE RULED OUT SUNDAY NIGHT INTO MONDAY AS THE BROAD UPPER LOW CONTINUES TO PUSH VORTICITY MAXIMA ACROSS THE AREA. CODED LOW CHANCE POPS FOR SUNDAY NIGHT INTO MONDAY. DESPITE OF WARM AIR ADVECTION ALOFT...EXPECT MILD TEMPERATURES DUE TO CLOUD COVER AND COOLING SHOWERS EFFECTS. WENT GENERALLY WITH THE CONSENSUS MOS GUIDANCE WITH SOME TWEAKS. KEPT WARMER TEMPS FOR A MUGGY SUNDAY NIGHT. LOW TURN NORTHWEST BY MONDAY BRINGING COOLER PLEASANT TEMPERATURES DURING THE FIRST HALF OF THE WEEK. CONDITIONS IMPROVE MONDAY AND MONDAY NIGHT. AS THE COLD FRONT EXITS...WITH PRECIP DECREASING FROM WEST TO EAST AND MUCH COOLER TEMPERATURES OVERSPREADING THE AREA.
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&& .LONG TERM /MONDAY THROUGH FRIDAY/...
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HIGH PRESSURE BEHIND THE COLD FRONT TAKES CONTROL LATER MONDAY NIGHT THROUGH THE MIDDLE OF NEXT WEEK WITH NEAR NORMAL TEMPERATURES. BLENDED HPC WITH PREVIOUS FORECAST NUMBERS AS THEY LOOK REPRESENTATIVE UNDER HIGH PRESSURE AND SLIGHTLY COOLER NORTHERLY FLOW.
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&& .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... VFR CONDITIONS WILL PREVAIL THIS AFTERNOON AND INTO THE EVENING HOURS...AND ONCE AGAIN BY AND AFTER 15Z SAT. CURRENTLY HAVE A FEW- SCT FLAT CUMULUS DECK OVER MUCH OF THE AREA AT ABOUT 3KFT-4KFT AGL...WHICH SHOULD QUICKLY DISSIPATE NEAR AND SHORTLY AFTER SUNSET. SOME IFR IN FOG MAY FORM 06Z TO 12Z SATURDAY IN THE DEEPER MOUNTAIN VALLEYS OF EASTERN AND SOUTHERN WEST VIRGINIA...INCLUDING ELKINS. HOWEVER...IT DOES NOT APPEAR AT THIS POINT THAT IT WILL BE QUITE AS WIDESPREAD AS THIS MORNING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE: HIGH DURING THE DAY...MEDIUM OVERNIGHT. ALTERNATE SCENARIOS: COVERAGE AND DENSITY OF FOG/REDUCED VIS MAY VARY FROM CURRENT FORECAST. 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. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z SATURDAY... IFR POSSIBLE IN ROUNDS OF CONVECTION SATURDAY NIGHT INTO SUNDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/50 NEAR TERM...50 SHORT TERM...ARJ LONG TERM...ARJ AVIATION...50

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