499
FXUS61 KRLX 270621
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
221 AM EDT THU AUG 27 2026
WHAT HAS CHANGED
POORER QUALITY MOISTURE POOLING AHEAD OF THE COLD FRONT HAS
SOMEWHAT REDUCED CONFIDENCE IN STRONG TO SEVERE THUNDERSTORM
COVERAGE FOR THIS AFTERNOON.
KEY MESSAGES
1.) PATCHY DENSE FOG LOCALIZED MAINLY TO MOUNTAIN VALLEYS EARLY
THIS MORNING, WITH CLOUD DEBRIS AND A TIGHTENING PRESSURE
GRADIENT LIMITING FOG ACROSS NORTHWESTERN LOCATIONS.
2.) ISOLATED TREE DAMAGE FROM GUSTY WINDS IS POSSIBLE WITH
AFTERNOON AND EVENING THUNDERSTORMS TODAY ACROSS THE FORECAST
AREA, THOUGH STORM COVERAGE REMAINS UNCERTAIN.
3.) HOT AND MOSTLY DRY WEATHER RETURNING FRIDAY THROUGH EARLY
NEXT WEEK ACROSS THE MIDDLE OHIO VALLEY AND CENTRAL
APPALACHIANS, WITH LOWLAND TEMPERATURES REACHING THE LOWER 90S.
DISCUSSION
KEY MESSAGE 1...
CONVECTION ASSOCIATED WITH AN UPSTREAM PREFRONTAL TROUGH IS
LARGELY FADING EARLY THIS MORNING, LEAVING REMNANT CONVECTIVE
CLOUD DEBRIS DRIFTING INTO THE FORECAST AREA. THIS CLOUD COVER,
COMBINED WITH A MODEST TIGHTENING OF THE SURFACE PRESSURE
GRADIENT AHEAD OF THE APPROACHING TROUGH, WILL LIMIT RADIATIONAL
COOLING AND HELP KEEP RIVER VALLEY FOG AT BAY THROUGH DAYBREAK
ACROSS THE NORTHWESTERN HALF OF THE AREA.
KEY MESSAGE 2...
THE OVERALL SEVERE THUNDERSTORM THREAT FOR THIS AFTERNOON AND
EVENING HAS BEEN TEMPERED DUE TO POORER QUALITY LOW-LEVEL
MOISTURE POOLING AHEAD OF THE SURFACE COLD FRONT. GUIDANCE THAT
TYPICALLY TRENDS MOIST, SUCH AS WRF-BASED MODELS, ONLY POOLS
SURFACE DEWPOINTS IN THE LOWER 70S, WHILE HIGH-RESOLUTION HRRR
AND MOS GUIDANCE SUGGEST AFTERNOON MIXING INTO THE MID TO UPPER
60S. WITH SURFACE HIGH TEMPERATURES REACHING THE MID TO UPPER
80S ACROSS THE LOWLANDS, MLCAPE VALUES WILL REACH 1000 TO 1500
J/KG. HOWEVER, MODEST CONVECTIVE INHIBITION AND DRIER BOUNDARY
LAYER AIR RAISE QUESTIONS REGARDING OVERALL CONVECTIVE COVERAGE,
ESPECIALLY WITH THE BEST SURFACE CONVERGENCE ALONG THE FRONT
GENERALLY LAGGING THE BEST RIBBON OF INSTABILITY.
DESPITE UNCERTAIN COVERAGE, ANY DEEP MOIST CONVECTION THAT
SUCCESSFULLY INITIATES WILL BE CAPABLE OF LOCALIZED SEVERE
HAZARDS. DEEP-LAYER 0-6KM BULK SHEAR OF 20 TO 25KTS WILL
SUPPORT SMALL CONVECTIVE CLUSTERS AND PERHAPS A TRANSIENT
SUPERCELLULAR STORM STRUCTURE FROM A SPLIT. BOUNDARY LAYER
PROFILES DISPLAY STEEP LOW-LEVEL LAPSE RATES BETWEEN 7.5 AND 8.5
C/KM AND LARGE DEWPOINT DEPRESSIONS BELOW H700, YIELDING DCAPE
VALUES OF 800 TO 1000 J/KG.
A MARGINALLY SEVERE HAIL REPORT WOULDN'T BE OUT OF THE QUESTION,
ALTHOUGH WET BULB ZEROS ARE RATHER HIGH GIVEN THE GENERALLY WEAK
INSTABILITY AND SHEAR, WOULD LIKELY REQUIRE A LEFT SPLIT TO
PRODUCE A LARGE ENOUGH STONE IN CLOUD TO CARRY SEVERE POTENTIAL
TO THE GROUND.
SPC DOES CONTINUE TO ADVERTISE A MARGINAL RISK FOR BOTH HAZARDS,
ALTHOUGH FORECAST CONTINUITY DOES SEEM TO BE AN INCREASING
FACTOR FOR MAINTAINING THIS. ANY STORM ACTIVITY THAT DOES FORM
WILL DIMINISH RAPIDLY BETWEEN 8 PM AND 10 PM EDT WITH NOCTURNAL
COOLING AND THE FRONTAL PASSAGE.
KEY MESSAGE 3...
UPPER-LEVEL TROUGHING WILL LINGER NEAR THE EAST COAST ON
FRIDAY, DRIVING A REINFORCING AND LARGELY DRY COLD FRONT ACROSS
THE REGION. COOLER NORTHWESTERLY FLOW WILL HOLD FRIDAY HIGH
TEMPERATURES IN THE LOWER 80S ACROSS THE LOWLANDS AND 70S IN THE
MOUNTAINS.
HEADING INTO THE WEEKEND AND EARLY NEXT WEEK, AN AMPLIFYING
UPPER-LEVEL RIDGE CENTERED OVER THE CENTRAL COUNTRY WILL SHIFT
EASTWARD AND ANCHOR OVER THE OHIO VALLEY AND CENTRAL
APPALACHIANS. FORECAST GUIDANCE KEEPS THE REGION FIRMLY
SUPPRESSED UNDER THE CORE OF THE RIDGE, KEEPING ANY SHORTWAVE
DISTURBANCES OR RIDGE-RIDER CONVECTIVE COMPLEXES WELL TO THE
NORTH ACROSS THE GREAT LAKES THROUGH AT LEAST THE MIDDLE OF NEXT
WEEK.
SENSIBLE WEATHER WILL TURN INCREASINGLY HOT FOR LATE AUGUST AND
EARLY SEPTEMBER. LOWLAND DAYTIME HIGHS WILL REACH THE UPPER 80S
ON SATURDAY AND RISE INTO THE LOWER 90S SUNDAY THROUGH TUESDAY.
DEWPOINTS MIXING INTO THE LOW AND MID 60S DURING PEAK AFTERNOON
HEATING WILL KEEP HEAT INDEX VALUES NEAR ACTUAL AIR
TEMPERATURES, KEEPING CONDITIONS BELOW HEAT HEADLINE CRITERIA.
AVIATION /06Z THURSDAY THROUGH MONDAY/
CONVECTIVE DEBRIS FROM DECAYING WESTERN STORMS WILL DRIFT ACROSS
THE REGION EARLY THIS MORNING AHEAD OF A PREFRONTAL TROUGH,
ACCOMPANIED BY A FEW LINGERING LIGHT RAIN SHOWERS. THE
COMBINATION OF CLOUD COVER AND A SLIGHTLY TIGHTENING PRESSURE
GRADIENT WILL LIMIT RIVER VALLEY FOG FORMATION ACROSS THE
NORTHWESTERN TERMINALS, THOUGH BRIEF IFR VISIBILITY IN FOG
REMAINS POSSIBLE AT EKN AND CRW THROUGH 12Z.
VFR CONDITIONS WILL PREVAIL AFTER 13Z WITH A DIURNALLY DRIVEN
CUMULUS DECK DEVELOPING AROUND 4000 TO 6000 FT AGL. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP BETWEEN 19Z
22Z AHEAD OF AN APPROACHING COLD FRONT. DIRECT THUNDERSTORM
HITS COULD PRODUCE BRIEF MVFR/IFR VISIBILITY RESTRICTIONS AND
GUSTY VARIABLE WINDS TO 30KTS. OVERALL CONFIDENCE ON CONVECTIVE
COVERAGE IS PRETTY LOW AND EVEN AT THE HIGHEST CONFIDENCE SITES
HAVE ONLY INCLUDED PROB30 TSRA GROUPS FOR NOW. CONVECTION WILL
DISSIPATE AFTER 02Z FRIDAY, WITH WINDS SHIFTING TO THE NORTHWEST
AROUND 5KTS BEHIND THE FRONT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: FOG COVERAGE THIS MORNING MAY VARY.
CONVECTIVE COVERAGE WILL BE RATHER SPOTTY THIS AFTERNOON, BUT
COULD AFFECT ANY TERMINAL.
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 THU 08/27/26
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 H H L L L L L H H H H H
HTS CONSISTENCY H H H L L L L H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L L H H H H
PKB CONSISTENCY H H H M L L L H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z FRIDAY...
PATCHY FOG POSSIBLE FRIDAY MORNING WHERE ANY HEAVIER
PRECIPITATION FALLS THURSDAY. VALLEY FOG LIKELY EACH MORNING THROUGH
THE WEEKEND.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
DISCUSSION...JP
AVIATION...JP
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