Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 011012
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
605 AM EDT WED OCT 1 2014

.SYNOPSIS...
WEAK HIGH PRESSURE/WEAK FLOW TODAY INTO EARLY THURSDAY.  STRONG COLD
FRONT STREAKS ACROSS FRIDAY AFTERNOON AND EVENING. MUCH COOLER AIR
ARRIVES FOR WEEKEND.  REINFORCING FRONT MAY ARRIVE EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
WHEN YOU GET DOWN TO THE DETAILS...IT IS NEVER EASY.

THE 88D VAD WIND PROFILES SINCE START OF GRAVEYARD
SHIFT...03Z...HAVE BEEN SHOWING STRONGER NE FLOW AT 925 MB THAN ANY
MODEL I HAVE LOOKED AT.  IT WAS NEAR 20 KNOTS...ABOUT 15
KNOTS AT 08Z.  THE EXPECTED STRATUS WE TALKED ABOUT YESTERDAY...ID
FORM...AND IS STILL MOVING SW AND STILL PENETRATING FURTHER S INTO
EASTERN KENTUCKY. DESPITE THE THIN NATURE OF THIS MOISTURE...WE ARE
STILL TRYING TO HOLD ONTO PLENTY OF CLOUDS THIS MORNING ACROSS THE
LOWLANDS...THE ONE EXCEPTION MAY BE THE HEADWATERS OF THE GUYANDOTTE
AND TUG FORK. FURTHER EAST AND SOUTHEAST...WAS NOT HITTING THE LOWER
STRATUS AS HARD IN THE MOUNTAIN COUNTIES AND UPPER GREENBRIER
VALLEY.  WHERE THE STRATUS FORMED...WAS NOT EXPECTING DENSE FOG.
AREAS THAT GOT MORE RAIN TUESDAY AFTERNOON AND EVENING ARE THE
EXCEPTION...WITH MORE FOG FOR PREDAWN AND DAWN...SUCH AS AROUND
CLARKSBURG.

TRIED TO SLOW DOWN THE DIURNAL RISE IN TEMPERATURE DURING THE 12Z TO
15Z TIME FRAME...JUST A BIT...FOR AREAS IN THE MID OHIO VALLEY
AROUND MARIETTA AND PARKERSBURG...WITH HIGHER CONFIDENCE IN CLOUDS
HOLDING THERE.  SOME 5 TO 6 MILES IN HAZE MAY LINGER TOO.

STILL TRY TO BREAK UP THE LEFTOVER STRATUS THIS AFTERNOON.

LEFT A 20 POP OVER THE CENTRAL MOUNTAIN COUNTIES THROUGH THE
AFTERNOON. IN WHAT FLOW THERE IS...A CONFLUENT PATTERN WITH WEAK
WESTERLIES W OF MOUNTAINS...AND EASTERLIES STILL E IN VIRGINIA.

JUST PLAYING UP MORE OF THE DIURNAL FOG OVERNIGHT TONIGHT.  THE
LONGER THE CLOUDS HOLD TODAY...THE SOONER IT FORMS DURING THE
NIGHT.

THOUGHT SOME OF THE MOS GUIDANCE WAS A BIT COLD TONIGHT...SUCH AS
THE 43 DEGREES ON BOTH THE GFS AND NAM MOS FOR ELKINS.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MAIN SYNOPTIC FEATURE FOR THE SHORT TERM IS A DECENT COLD FRONT
WHICH WILL MOVE THROUGH FRIDAY INTO FRIDAY NIGHT...AND RELATED UPPER
LEVEL TROUGH DIGGING IN BEHIND IT.

THE COLD FRONT IS ASSOCIATED WITH A DEEPENING SURFACE LOW MOVING
THROUGH THE WESTERN GREAT LAKES FRIDAY. SOME DISCREPANCIES ON TIMING
BETWEEN THE MODELS...THE CMC IS THE FASTEST...AND APPEARS TO FAST.
THE GFS AND ECMWF ARE FAIRLY SIMILAR...WITH THE NAM LAGGING BEHIND.
WENT MAINLY WITH A GFS/ECMWF BLEND WHICH DID NOT CHANGE MUCH FROM
THE PREVIOUS FORECAST. HAVE AN AREA OF LIKELY POPS AHEAD OF THE
FRONT. FLOW IS PRETTY FAST...SO EXPECT INDIVIDUAL CELLS TO BE FAST
MOVING. THERE IS NOT A WHOLE LOT OF INSTABILITY...BUT STILL HAVE
GOOD FORCING WITH THE FRONT. SO HAVE DECENT CHANCES OF THUNDER
FRIDAY AFTERNOON AND EVENING. WITH MARGINAL INSTABILITY...AND THE
BEST SHEAR LAGGING WELL BEHIND...AGREE WITH SPC ANALYSIS THAT SEVERE
STORMS ARE NOT ALL THAT LIKELY. BUT WITH THE FAST MOVEMENT...ANY
OUTFLOW WILL ALREADY HAVE A DECENT SYNOPTIC VELOCITY TO FEED OFF OF.
ANTICIPATING AN SPS COULD BE NEEDED FOR STRONGER CELLS...WILL
INCLUDE GUSTY OUTFLOW MENTION IN HWO.

WITH THE UPPER LEVEL TROUGH CROSSING SATURDAY...HAVE SLIGHT CHANCE
POP ACROSS THE NORTHERN CWA. PROBABLY COULD HAVE INCREASED TO CHANCE
BASED ON MODELS SHOWING GOOD UPPER LEVEL FORCING...HOWEVER
MOISTURE WILL BE VERY LIMITED BEHIND THE COLD FRONT.

FOR HIGHS AND LOWS...BLENDED IN MET GUIDANCE THURSDAY THROUGH FRIDAY
THEN TRANSITIONED TO A WPC/BIAS-CORRECTED CONSENSUS BLEND IN THE
VERY COOL AIR BEHIND THE FRONT. HAVE HIGHS ON SATURDAY STRUGGLING TO
REACH 60.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
THE AREA DOES REMAIN IN THE BAROCLINIC ZONE MUCH OF THE PERIOD AS
THE SWD EXTENT OF THE L/W DOES RETREAT. THIS MAKES IT DIFFICULT TO
TIME THE COOLEST WEATHER OTHER THAN THE INITIAL SHOT SAT NT...WHICH
IS NOW CODED UP AS THE COOLEST PART OF THE FCST. THIS INCLUDES
POTENTIALLY FROSTY TEMPERATURES FOR THE NRN WV MOUNTAINS AND IN SE
OH COME SUN MORNING.

THE NEXT REINFORCING S/W TROUGH BRINGS THE CHANCE FOR SHOWERS
SOMETIME EARLY NEXT WEEK...WITH MODEL DIFFERENCES AS TO ITS TIMING
ALONG WITH TIMING THE ARRIVAL OF THE REINFORCING COOL AIR BEHIND IT
SO COULD NOT REALLY DEPICT NEXT COOL DOWN EVEN ON DAY 7 NT.

BLENDED IN WPC AND THE LOW MEX FOR LOWS SAT NT...AGAIN ON LOW END OF
GUIDANCE.  WILL NOT HWO FROST DAY 4 NT THOUGH PENDING HOW FAVORABLE
SAT NT TURNS OUT FOR RADIATIVE COOLING.  BLENDED IN WPC TEMPERATURES
FOR THE LESS CERTAIN BALANCE OF THE EXTENDED.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
THE EXPECTED STRATUS CEILINGS ARE WELL ENTRENCHED NEAR DAWN IN THE
OHIO VALLEY COUNTIES.  THE NE LOW LEVEL FLOW AT 925 MB IS FINALLY
BEGINNING TO WEAKEN.  NEAR 10Z THE RLX VAD WAS RUNNING NEAR 10
KNOTS...COMPARED TO 20 KNOTS AROUND 06Z.

WILL CONTINUE TO HIGHLIGHT CEILINGS ON EITHER SIDE OF 1 THSD FT
BKN/OVC FOR THE OHIO VALLEY COUNTIES.  THE SE EDGE OF THE WIDESPREAD
STRATUS CEILINGS WAS RUNNING FORMING JUST E OF THE CKB-CRW CORRIDOR
ON SW TO NEAR SJS AND JKL IN ERN KENTUCKY.  FORMING THE STRATUS
RATHER THAN DENSE SURFACE BASED FOG SEEMED TO BE THE RIGHT CALL FOR
CRW THAT THE 00Z AND 06Z SET OF TAFS WENT WITH.

STILL DO NOT EXPECTED THE WIDESPREAD STRATUS TO REACH OVER THE
CENTRAL AND SOUTHERN MOUNTAINS.  MORE VALLEY FOG AROUND EKN AND THE
SOUTHERN WV COAL FIELDS.

STILL EXPECT THE THIN STRATUS TO BE STUBBORN TO ERODE/LIFT DURING
THE 12Z TO 18Z TIME FRAME TODAY...ESPECIALLY IN THE MID OHIO VALLEY
COUNTIES NEAR PKB.  18Z IS NOT OUT OF THE QUESTION FOR THE IFR/MVFR
CONDITIONS.

A FEW SPOTTY SHOWERS STILL POSSIBLE THROUGH AFTERNOON OVER THE WEST
VIRGINIA CENTRAL MOUNTAIN COUNTIES.

HAVE MOSTLY SCATTERED CLOUDS BY 00Z THURSDAY.  DIURNAL FOG MAY BE
FORMING FIRST...03Z TO 06Z THURSDAY...IN THE MOUNTAIN VALLEYS AROUND
CRW.  HAVE IFR/LIFR IN RIBBONS OF VALLEY FOG 06Z TO 12Z
THURSDAY.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...

FORECAST CONFIDENCE: LOW.

ALTERNATE SCENARIOS: TIMING THE LIFTING AND BREAK UP OF THE THIN BUT
LOW STRATUS CEILINGS 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 10/01/14
UTC 1HRLY       08   09   10   11   12   13   14   15   16   17   18   19
EDT 1HRLY       04   05   06   07   08   09   10   11   12   13   14   15
CRW CONSISTENCY  H    M    M    H    H    H    H    M    M    M    M    M
HTS CONSISTENCY  H    H    H    H    H    H    H    M    M    M    M    M
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M
PKB CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M
CKB CONSISTENCY  L    L    L    L    L    H    H    H    M    M    M    M

AFTER 12Z THURSDAY...
BRIEF IFR POSSIBLE IN FAST MOVING SHOWERS AND/OR THUNDERSTORMS
FRIDAY INTO FRIDAY NIGHT.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...TRM
AVIATION...KTB










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