870
FXUS61 KRLX 081757
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
157 PM EDT THU OCT 8 2026
WHAT HAS CHANGED
DEWPOINTS AND OVERNIGHT LOWS HAVE BEEN LOWERED FOR THIS
AFTERNOON THROUGH FRIDAY NIGHT, WITH VALLEY FOG BOTH NIGHTS AND
PERHAPS SOME VERY PATCHY FROST IN PROTECTED MOUNTAIN VALLEYS
TONIGHT. THE REMNANT TRACK OF ISAIAS IS FARTHER WEST WITH
EXTRATROPICAL REMNANT LOW FARTHER SOUTH, SO THE HEAVIER RAIN IS
NOW FOCUSED ON THE MIDDLE OHIO VALLEY WITH A SIGNIFICANT RAIN
SHADOW IN THE LEE OF THE HIGHER TERRAIN. DOWNSLOPE GUSTS
SATURDAY NIGHT INTO SUNDAY REMAIN GENERALLY BELOW ADVISORY
CRITERIA OUTSIDE A VERY TIGHT FOOTPRINT ON THE WESTERN SLOPES.
THE ALREADY LOW POTENTIAL FOR TORNADOES ON SUNDAY HAS DECREASED
FARTHER, ALTHOUGH STILL NON-ZERO.
KEY MESSAGES
1.) DRY AIR AND EFFICIENT RADIATIONAL COOLING BRING COOL
NIGHTS AND VALLEY FOG THROUGH FRIDAY NIGHT.
2.) REMNANTS OF ISAIAS BRING A PRIMARILY BENEFICIAL SOAKING
LATE SATURDAY THROUGH SUNDAY NIGHT, HEAVIEST TOWARD THE MIDDLE
OHIO VALLEY, WITH ONLY AN ISOLATED HIGH-WATER RISK.
3.) GUSTY SOUTHEAST DOWNSLOPE WINDS DEVELOP SATURDAY NIGHT INTO
SUNDAY IN THE IMMEDIATE LEE OF THE HIGHER TERRAIN.
4.) HIGH PRESSURE RETURNS BRIEFLY MONDAY, THEN A WEAK COLD
FRONT CROSSES TUESDAY NIGHT.
DISCUSSION
KEY MESSAGE 1...
A MOISTURE-STARVED COLD FRONT HAS ALREADY CLEARED THE FORECAST
AREA. EARLY AFTERNOON OBSERVATIONS ARE CLEAR AREAWIDE, WITH
TEMPERATURES ALREADY IN THE UPPER 60S TO MID 70S AND DEWPOINTS
RANGING FROM THE LOWER 40S TO THE LOWER 50S. WE WILL CONTINUE TO
MIX INTO A DRY LAYER ALOFT THIS AFTERNOON WITH DEW POINTS
CONTINUING TO TREND DOWN. HAVE REDUCED VALUES OVER CENTRAL
GUIDANCE WHICH IS TYPICALLY TOO HIGH IN THIS DRY AIR ALOFT
SETUP, ESPECIALLY IN THE SHOULDER SEASONS. AFTERNOON RELATIVE
HUMIDITY SHOULD FALL INTO THE UPPER 20S TO MID 30S IN THE
LOWLANDS AND THE 30S TO AROUND 40 PERCENT IN THE MOUNTAINS. TEN-
HOUR FUEL MOISTURE AT SEVERAL RAWS SITES WAS ALREADY IN THE 6 TO
10 PERCENT RANGE BY EARLY AFTERNOON, SO FINE DEAD FUELS AND
LEAF LITTER ARE RECEPTIVE, BUT WITH LEAVES LARGELY STILL SHADING
THE FOREST FLOOR AND WINDS REMAINING RELATIVELY LIGHT THIS IS A
DRYING DAY RATHER THAN A CRITICAL FIRE WEATHER DAY.
HIGHS THIS AFTERNOON REACH THE MID TO UPPER 70S ACROSS THE
LOWLANDS AND METRO VALLEY, WITH 60S TO AROUND 70 IN THE HIGHER
TERRAIN AND UPPER 50S ON THE HIGHEST NORTHEAST MOUNTAIN RIDGES.
FRIDAY IS A NEAR-REPEAT UNDER THE SURFACE HIGH, WITH ANOTHER
ROUND OF MIXING INTO DRY AIR AND AFTERNOON HUMIDITY AGAIN IN THE
30S FOR MUCH OF THE AREA. HIGHS FRIDAY LAND IN THE MID TO UPPER
70S IN THE LOWLANDS AND THE 60S IN THE MOUNTAINS.
TONIGHT IS THE BETTER RADIATIONAL-COOLING SETUP. WINDS GO CALM,
SKIES STAY CLEAR, AND DEWPOINTS ARE LOW. LOWS FALL INTO THE LOW
TO MID 40S IN THE LOWLANDS, AND INTO THE UPPER 30S TO AROUND 40
IN AREAS SUBJECT TO COLD AIR DRAINAGE AWAY FROM MAJOR RIVERS.
THAT IS SEVERAL DEGREES COLDER THAN RAW CENTRAL GUIDANCE, WHICH
HOLDS THE LOWER ELEVATIONS NEAR 50 DEGREES WITH MOUNTAIN VALLEYS
GENERALLY IN THE 40S. VALLEY FOG IS LIKELY AFTER MIDNIGHT ALONG
THE RIVER VALLEYS AND IN OTHER COLD-AIR DRAINAGE VALLEYS, AS
RIVER TEMPERATURES REMAIN WARMER THAN THE OVERLYING AIR. THE
SAME SETUP REPEATS FRIDAY NIGHT. WHERE FOG DOES NOT FORM IN
PROTECTED MOUNTAIN VALLEYS, VERY ISOLATED PATCHY FROST IS
POSSIBLE TOWARD SUNRISE FRIDAY. COVERAGE SHOULD BE LIMITED, AND
THIS IS PRETTY LATE IN THE GROWING SEASON FOR A MARGINAL EVENT,
SO WILL NOT HOIST ANY FROST ADVISORIES AT THIS TIME.
KEY MESSAGE 2...
HURRICANE ISAIAS WAS CENTERED ABOUT 150 NM NORTH OF THE YUCATAN
PENINSULA, WITH MAXIMUM SUSTAINED WINDS NEAR 75KTS AND A
CENTRAL PRESSURE NEAR 975 MB AS OF THE 10 AM NHC FORECAST
UPDATE. IT IS EXPECTED TO TURN NORTH AND MAKE LANDFALL ON THE
NORTHERN GULF COAST LATE FRIDAY NIGHT OR EARLY SATURDAY,
CONTINUING NORTH INTO SUNDAY MORNING, THEN EJECT QUICKLY TO THE
EAST NORTHEAST AS AN EXTRATROPICAL LOW SUNDAY INTO SUNDAY NIGHT.
STILL SOME UNCERTAINTY AS TO HOW THIS EVOLVES; EXPECT MUCH MORE
CLARITY AFTER ISAIAS MAKES LANDFALL.
A SURGE OF TROPICAL MOISTURE SHOULD BEGIN TO REACH THE FORECAST
AREA AS EARLY AS SATURDAY AFTERNOON, WITH RAIN THEN PERSISTING
THROUGH AT LEAST LATE SUNDAY NIGHT AS THAT MOISTURE OVERRUNS THE
APPROACHING TROUGH. A GENERAL 1 TO 2 INCHES IS EXPECTED. ANY
HEAVIER RAIN FOCUSES ON THE MIDDLE OHIO VALLEY INTO THE TUG FORK,
WITH MEANINGFUL RAIN SHADOWING WEST OF THE SPINE OF THE HIGHER
TERRAIN. THE HEAVIEST RATES SHOULD COME LATE SUNDAY MORNING INTO
SUNDAY AFTERNOON, WHERE WARM-CLOUD DEPTHS ARE DEEP AND CAPE IS
SKINNY UP THROUGH AROUND H400. ANTECEDENT CONDITIONS ARE DRY
AND SOILS SHOULD TAKE MOST OF THIS PRIMARILY BENEFICIAL RAIN.
ISOLATED HIGH WATER IS STILL POSSIBLE WHERE A HEAVIER BAND SITS
ON A NARROW HOLLOW OR A POOR-DRAINAGE SPOT, BUT A WIDESPREAD
HIGH WATER IS NOT EXPECTED. RAIN TAPERS SUNDAY NIGHT INTO MONDAY
MORNING AS THE WEAKENING SYSTEM LIFTS TOWARD THE ATLANTIC, AND
MONDAY IS A BRIEF DRY BREAK.
THE FARTHER WEST AND SOUTH POSITION OF THE REMNANT LOW ALSO CUTS
THE TORNADO POTENTIAL RELATIVE TO YESTERDAY. THE BETTER LOW-
LEVEL TURNING STAYS WELL TO OUR SOUTHEAST. COULD STILL SEE A
NARROW WINDOW OF HEATING ALLOWING SURFACE BASED PARCEL ASCENT
COLLOCATED WITH SOME BETTER LOW LEVEL TURNING ACROSS THE
SOUTHERN COALFIELDS WHICH COULD YIELD SOME ROTATING SHOWERS OR
THUNDERSTORMS SUNDAY AFTERNOON. SHOULD THIS MATERIALIZE, THE
TORNADO POTENTIAL WOULD BE LOW, BUT NOT ZERO.
KEY MESSAGE 3...
SOUTHEAST FLOW STRENGTHENS SATURDAY NIGHT AS THE REMNANT
CIRCULATION APPROACHES. FORECAST PROFILES SHOW A 40 TO 50KT
SOUTHEAST JET DEVELOPING NEAR H850 TO H800 BY SUNDAY MORNING. IN
THE IMMEDIATE LEE OF THE HIGHER TERRAIN, THAT SUPPORTS
DOWNSLOPE GUSTS OF 30 TO 40 MPH BEGINNING SATURDAY NIGHT AND
PERSISTING THROUGH MUCH OF SUNDAY, MAINLY ON THE WESTERN SLOPES
OF THE HIGHER TERRAIN. CENTRAL GUIDANCE DOES HAVE A MARGINAL
SIGNAL (SLIGHTLY GREATER THAN 50 PERCENT CHANCE) OF SOME
ISOLATED 45 MPH GUSTS WHERE ISENTROPIC DOWNGLIDE OF PARCELS
INTERSECTS THE TERRAIN, BUT THIS SHOULD BE VERY SPATIALLY
LIMITED IF IT OCCURS.
ELSEWHERE, GUSTS OF 20 TO 30 MPH ARE POSSIBLE LATE SATURDAY
NIGHT INTO SUNDAY MORNING, PRIOR TO THE BOUNDARY LAYER
SATURATING AND MAKING MIXING OF HIGHER MOMENTUM AIR MORE
DIFFICULT. GUSTS SHOULD EASE THROUGH SUNDAY LATE AFTERNOON.
KEY MESSAGE 4...
HIGH PRESSURE BUILDS BACK IN MONDAY BEHIND THE DEPARTING REMNANT
LOW, WITH A RETURN TO DRY WEATHER AND SEASONABLE TEMPERATURES.
ANOTHER WEAK COLD FRONT, TIED TO LOW PRESSURE PASSING WELL NORTH
OF THE AREA, CROSSES TUESDAY NIGHT. MOISTURE AND FORCING BOTH
LOOK LIMITED, SO THIS IS A LOW-END SHOWER CHANCE RATHER THAN
ANOTHER SOAKING, FOLLOWED BY SLIGHTLY COOLER AND DRIER AIR FOR
THE MIDDLE OF NEXT WEEK.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
VFR AND CLEAR THIS AFTERNOON AND EVENING. NORTHWEST WINDS 5 TO
10KTS WITH A FEW GUSTS TO 15 TO 20KTS DIMINISH TO CALM OR LIGHT
AND VARIABLE AFTER SUNSET.
HIGHLY EFFECTIVE RADIATIONAL COOLING SUPPORTS VALLEY FOG LATE
THIS EVENING INTO THE OVERNIGHT, MOST LIKELY AFTER MIDNIGHT,
WITH IFR TO LIFR VISIBILITY AND CEILINGS POSSIBLE AT ALL SITES
MINUS BKW BY MORNING. ANY FOG LIFTS BY 14Z FRIDAY, WITH VFR AND
LIGHT WIND RETURNING FOR FRIDAY AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: HIGH TODAY. MEDIUM FOR FOG TONIGHT.
ALTERNATE SCENARIOS: EXTENT OF RIVER VALLEY FOG TONIGHT MAY
VARY FROM THE 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 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 H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z FRIDAY...
IFR IS POSSIBLE IN VALLEY FOG SATURDAY MORNING AND RAIN
SATURDAY NIGHT THROUGH SUNDAY NIGHT.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
DISCUSSION...JP
AVIATION...JP
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