811
FXUS61 KRLX 061744
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
144 PM EDT TUE OCT 6 2026
WHAT HAS CHANGED
ADJUSTED AFTERNOON DEW POINTS DOWN TODAY AND REDUCED OVERNIGHT
VALLEY TEMPERATURES TONIGHT.
KEY MESSAGES
1.) LOCALIZED VISIBILITY REDUCTIONS IN RIVER VALLEY FOG LATE
TONIGHT THROUGH WEDNESDAY MORNING ACROSS LOWLAND AND MOUNTAIN
VALLEYS, ALONG WITH A SHARP RIDGE-VALLEY TEMPERATURE SPLIT AND
PATCHY MOUNTAIN FROST.
2.) DRY AND UNSEASONABLY MILD WEATHER THROUGH SATURDAY, WITH A
WEAK AND DRY COLD FRONTAL PASSAGE THURSDAY MORNING.
3.) INCREASING RAIN CHANCES LATE SATURDAY NIGHT INTO EARLY NEXT
WEEK.
DISCUSSION
KEY MESSAGE 1...
SURFACE HIGH PRESSURE WILL DOMINATE THE REGION THROUGH
WEDNESDAY MORNING. AFTERNOON DEW POINTS WERE LOWERED INTO THE
UPPER 30S TO LOWER 40S GIVEN EFFICIENT BOUNDARY-LAYER MIXING
UNDER CLEAR SKIES. FOR TONIGHT, CLEAR SKIES AND LIGHT SURFACE
WINDS WILL SUPPORT RAPID DECOUPLING IN THE VALLEYS AFTER SUNSET.
HOWEVER, LOW-LEVEL WIND PROFILES SHOW FLOW JUST OFF THE SURFACE
INCREASING TO 10 TO 15KTS OVERNIGHT. THIS WILL SET UP A
PRONOUNCED RIDGE-VALLEY TEMPERATURE SPLIT BY WEDNESDAY MORNING.
DEEP VALLEY INVERSIONS WILL FOSTER RIVER VALLEY FOG DEVELOPMENT
AFTER MIDNIGHT. WHILE FOG WILL BE WIDESPREAD IN LOWER RIVER
BASINS, THE INCREASING FLOW ALOFT SHOULD KEEP DENSE FOG LARGELY
CONFINED TO THE VALLEYS FLOORS.
PATCHY FROST IS POSSIBLE IN ISOLATED MOUNTAIN COLD SPOTS AWAY
FROM RIVERS WHERE FOG FAILS TO FORM (WHICH SHOULD YIELD VERY
LIMITED, IF ANY, COVERAGE). GIVEN THE LIMITED SPATIAL COVERAGE
AND THE LATE STAGE OF THE GROWING SEASON IN THE HIGHEST TERRAIN,
WILL FORGO ISSUANCE OF ANY FROST HEADLINES. FOG WILL BURN OFF
AROUND 14Z WEDNESDAY MORNING.
KEY MESSAGE 2...
SURFACE HIGH PRESSURE SHIFTS OFF THE MID-ATLANTIC COAST ON
WEDNESDAY, ESTABLISHING SOUTHWESTERLY RETURN FLOW. BUILDING
UPPER-LEVEL HEIGHTS WILL YIELD DAYTIME HIGH TEMPERATURES
REACHING THE UPPER 70S TO LOW 80S ACROSS THE LOWLANDS, WHICH IS
AROUND 10 DEGREES ABOVE SEASONAL NORMALS. A NORTHERN STREAM
SHORTWAVE TROUGH TRAVERSING QUEBEC AND THE GREAT LAKES ON
THURSDAY WILL PUSH A WEAK COLD FRONT THROUGH THE AREA THURSDAY
MORNING. SOUNDINGS REVEAL VERY SHALLOW BOUNDARY-LAYER MOISTURE
WITH DRY AIR ABOVE H850, KEEPING POPS NEAR ZERO WITH NO
MEASURABLE RAINFALL EXPECTED. LOW-LEVEL FLOW SHIFTS TO THE
NORTHWEST BEHIND THE FRONT, KNOCKING AFTERNOON HIGHS BACK INTO
THE MID-70S TO NEAR 80 DEGREES FOR FRIDAY, BEFORE TEMPERATURES
QUICKLY REBOUND INTO THE LOW 80S ON SATURDAY.
KEY MESSAGE 3...
ATTENTION TURNS TO THE LATE WEEKEND AS INVEST 92L IN THE
SOUTHWESTERN GULF EVOLVES. HIGH CONFIDENCE EXISTS IN TROPICAL
CYCLONE DEVELOPMENT OVER THE GULF OVER THE NEXT COUPLE OF DAYS
AS THE SYSTEM TRACKS NORTH TO NORTHEAST. AS AN UPPER-LEVEL
TROUGH OVER THE CENTRAL US INTERACTS WITH THIS TROPICAL SYSTEM,
A DEEP PLUME OF TROPICAL MOISTURE WILL LIFT NORTHWARD INTO THE
TENNESSEE AND OHIO VALLEYS. MODEL GUIDANCE INDICATES
PRECIPITABLE WATER VALUES INCREASING SIGNIFICANTLY LATE SATURDAY
NIGHT INTO SUNDAY. WHILE SPATIAL AND TIMING DISCREPANCIES REMAIN
REGARDING THE EXACT SURFACE LOW TRACK AND TROUGH INTERACTION,
CONFIDENCE IS INCREASING IN WIDESPREAD RAINFALL OVERSPREADING
THE FORECAST AREA LATE SATURDAY NIGHT THROUGH SUNDAY. ENSEMBLES
SUGGEST GENERAL 24-HOUR RAINFALL TOTALS OF 1.0 TO 1.5 INCHES
ACROSS THE AREA. DETAILS ON QPF TRENDS AND POTENTIAL EXCESSIVE
RAINFALL RISKS WILL BE REFINED AS THE GULF SYSTEM ORGANIZES.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
VFR CONDITIONS PREVAIL THROUGH THIS EVENING UNDER CLEAR SKIES
WITH LIGHT SURFACE WINDS UNDER 5KTS. VALLEYS WILL DECOUPLE
RAPIDLY AFTER SUNSET, SETTING UP RIVER VALLEY FOG DEVELOPMENT
BETWEEN 06Z AND 08Z. FOG BURNS OFF BY 14Z WEDNESDAY, RETURNING
ALL TERMINALS TO VFR UNDER CLEAR SKIES WITH SOUTHWESTERLY
SURFACE WINDS OF 5 TO 10KTS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: HIGH, EXCEPT MEDIUM FOR FOG COVERAGE
OVERNIGHT.
ALTERNATE SCENARIOS: INCREASING LOW-LEVEL FLOW JUST ABOVE THE
BOUNDARY LAYER MAY KEEP DENSE FOG CONFINED MOSTLY TO SHELTERED
VALLEYS.
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 17 18 19 20 21 22 23 00 01 02 03 04
EDT 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
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 M
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z WEDNESDAY...
VFR CONDITIONS DOMINATE THROUGH SATURDAY OUTSIDE OF LATE-NIGHT
AND EARLY-MORNING RIVER VALLEY FOG. CEILING AND VISIBILITY
RESTRICTIONS IN RAIN ARE POSSIBLE BEGINNING AS EARLY AS LATE
SATURDAY NIGHT.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
DISCUSSION...JP
AVIATION...JP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page