Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 301805
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
205 PM EDT TUE SEP 30 2014

.SYNOPSIS...
MID/UPPER LEVEL DISTURBANCE SWINGS SOUTHEAST...BRUSHES AREA THIS
AFTERNOON/EVENING. WEAK HIGH PRESSURE/LIGHT WINDS WEDNESDAY INTO
EARLY THURSDAY  STRONG COLD FRONT FRIDAY. MUCH COOLER WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
130 PM UPDATE...
SHOWERS CURRENTLY PROGRESSING EASTWARD ACROSS THE FAR NW ZONES AT
THIS TIME. THESE ARE PART OF THE LARGER LINE OF SHRA TO THE NORTH
ACROSS WESTERN PA AND NW OHIO. WHILE THAT PORTION OF THE LINE IS
MOVING EAST QUICKER...THE SOUTHERN PART OF THE LINE AFFECTING OUR
AREA IS SLOWER AS TO BE EXPECTED. THIS TREND SHOULD CONTINUE. MAY
BE MORE REDEVELOPMENT ACROSS SE OHIO LATER THIS AFTERNOON.

1030 AM UPDATE...
FIRST LINE OF CONVECTION WITH SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS ALREADY NEARING PERRY COUNTY AT THIS TIME. RAMPED
UP POPS TO THE LIKELY CATEGORY FOR THOSE LOCATIONS NEAR OUR
NORTHWEST FORECAST AREA BORDER FROM PERRY COUNTY OVER TOWARDS
MORGAN AND WASH COUNTIES IN OHIO FOR THE NEXT 1-3 HOURS AS IT
QUICKLY MOVES EAST.

PREVIOUS DISCUSSION...
PATCHES OF CLOUDS STILL OVER THE MOUNTAINS AT 07Z...OTHERWISE
VALLEY FOG PREVAILS. WATER VAPOR IMAGERY DEPICTS MID/UPPER TROF
OVER LAKE HURON AND MICHIGAN DROPPING SOUTHEAST. ASSOCIATED COLD
FRONT/WIND SHIFT WAS APPROACHING TOL AND STILL NORTH OF IND.

AS MENTIONED YESTERDAY...THE MAIN COOLING ALOFT TODAY WILL BE NORTH
OF OUR CWA.  FOR EXAMPLE...00Z NAM HAS 500 MB TEMP AT PBZ COOLING
ABOUT 5C TODAY...WHILE CKB ONLY ABOUT A DEG C.  SO TIMING THE
POPS...AND HOW FAR SOUTH TO MENTION PCPN FOR THIS AFTERNOON AND
TONIGHT IS ONE CHALLENGE.  AFTER DIGESTING THE MODELS...SEE NO
REASON TO CHANGE THE SLIGHT CHANCE POP REACHING AS FAR SOUTH AS
HTS-CRW VCNTY FOR THIS EVENING.  THIS IS A BIT FURTHER SOUTH THAN
MOST 00Z MODEL SOLUTIONS.  FURTHER NNE...HAVE POPS MAXING OUT AROUND
40 TO 50 PCT FOR N CNTRL WV FROM 21Z TODAY TO 01Z WEDNESDAY.

DRY AIR SOUTH OF THAT DISTURBANCE FOR TODAY. RAP SOLUTION TRIES TO
EVEN LOWER DEW POINTS INTO THE 40S.  MAYBE ACROSS HIGH TERRAIN LIKE
BKW...BUT DID NOT GO THAT LOW IN THE WESTERN LOWLANDS.

MAIN PUSH BEHIND FRONT IS INTO SOUTHEAST OHIO...BEFORE 925 MB WINDS
QUICKLY VEER TO EAST OR DIMINISH TO CALM.  THINKING LOW STRATUS WILL
FORM TONIGHT IN SE OHIO BEHIND FRONT.  FURTHER SOUTH IN THE COAL
FIELDS OF WV...WAS THINKING JUST THE USUAL DIURNAL LATE NIGHT FOG.
FURTHER NORTH...LINGERING CLOUDS MAY HINDER OR DELAY THE FOG
FORMATION AROUND CKB AND EKN.  HTS-CRW CORRIDOR IS A TOUGH CALL
BETWEEN ALL 3 FOR LATE TONIGHT...PATCHES OF CLOUDS LINGERING
OVERNIGHT...STRATUS FORMATION...OR SURFACE BASED FOG FORMING.
OVERALL KEPT MINIMUM TEMPERATURE ON THE HIGH SIDE OF GFS MOS
GUIDANCE.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
UPPER LEVEL LOW WILL BE HEADING EAST OUT TO SEA TO START THE SHORT
TERM PERIOD. IN THE WAKE OF THIS LOW...ANTICIPATE LOTS OF LOW
STRATUS WEDNESDAY MORNING...GRADUALLY BREAKING UP THROUGH THE DAY.
ONE EXCEPTION WILL BE FAR SOUTHERN CWA WHERE DO NOT EXPECT THESE
CLOUDS. WITH THE EXPECTED CLOUDS...ALSO LOWERED HIGHS ON WEDNESDAY
SEVERAL DEGREES IN SE OHIO. BLENDED BIAS CORRECTED MET INTO PREVIOUS
FORECAST. HAVE A LITTLE TRAILING VORT MAX COMING THROUGH WEDNESDAY
INTO WEDNESDAY NIGHT SO HAVE SOME SLIGHT CHANCE TO CHANCE POPS IN
THE NORTHERN MOUNTAINS...BUT DRY ELSEWHERE. WEAK SURFACE HIGH
PRESSURE AND UPPER LEVEL RIDGING PASSES THURSDAY WITH A
WARMER...SUNNY DAY. AGAIN BLENDED IN BIAS CORRECTED MET. BY THURSDAY
NIGHT...CLOUDS INCREASING AHEAD OF A COLD FRONT APPROACHING FROM THE
WEST. FOR LOWS WEDNESDAY AND THURSDAY NIGHTS...BLENDED IN BIAS
CORRECTED CONSENSUS GUIDANCE.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
L/W TROUGH SETTLES IN OVER THE AREA THIS PERIOD.  RAIN IS MOST
LIKELY FRI AS LEAD SRN STREAM S/W TROUGH CROSSES JUST OUT AHEAD OF
SFC COLD FRONT...WHICH IS DRIVEN BY MID STREAM S/W PIVOTING THROUGH
THE LOWER GREAT LAKES AND OHIO VALLEY FRI...DRIVING THE SFC COLD
FRONT THROUGH LATE FRI AFTERNOON AND EVENING.

STRONG FLOW...FORCING...LAST MINUTE LOW LEVEL MOISTURE CONVERGENCE
AND LATE DAY TIMING SHOULD SUPPORT THE CHANCE FOR THUNDER...ALTHOUGH
A MITIGATING FACTOR IS THE LEAD SRN STREAM S/W...WHICH BRINGS CLOUDS
AND RAIN ACROSS EARLIER IN THE DAY.

A HIGH OF MAINLY PACIFIC ORIGIN BUILDS IN BEHIND THE FRONT
INITIALLY...BRINGING ABOUT A FAIR...COOL WEEKEND.  A REINFORCING
UPPER LEVEL S/W TROUGH AND SFC FRONT CROSS MON...WITH A CHANCE FOR
SHOWERS...AND THEN EVEN COOLER WEATHER EARLY NEXT WEEK.

BLENDED IN GFS BASED GUIDANCE FOR HIGHS FRI AND THEN MAINLY WPC FOR
LOWS AND HIGHS BEYOND THAT...MOST CHANGES TO LOWER VALUES BUT NOT BY
MUCH.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
GENERALLY VFR CONDITIONS BEING EXPERIENCED THIS AFTERNOON. A LINE
OF SHOWERS CURRENTLY PUSHING SLOWLY ACROSS SE OHIO INTO THE
PANHANDLE OF WV SHOULD CONTINUE SLOWLY EASTWARD THIS
AFTERNOON...MAINLY NEAR AND NORTH OF US HWY 50. BRIEF MVFR/IFR
VIS IS POSSIBLE UNDERNEATH A HEAVIER SHOWER BUT AGAIN...VFR
CONDITIONS SHOULD BE PREVALENT OTHERWISE.

EXPECT LOWER MVFR/IFR CEILINGS TO MOVE SOUTH INTO SOUTHEAST OHIO
00Z TO 06Z WEDNESDAY...BEHIND THE FRONT CURRENTLY JUST TO THE
NORTHWEST. A GOOD DEAL OF UNCERTAINTY EXISTS MAINLY FOR THE
CENTRAL WV LOWLANDS WITH EXACTLY HOW FAR EAST AND SOUTH IT
PROGRESSES...WITH LOW STRATUS AND/OR FOG POSSIBLE IN THIS GENERAL
AREA. THINKING MORE DIURNAL FOG WILL FORM ACROSS SOUTHERN WEST
VIRGINIA BY 06Z WEDNESDAY.

EXPECT SLOWLY IMPROVING CONDITIONS DURING THE MORNING HOURS BTWN
15Z-18Z.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: COVERAGE OF SHOWERS MAY BE MORE THAN FORECAST
IN THE PKB-CKB-EKN VCNTY. ARRIVAL OF LOWER STRATUS CEILING INTO
SOUTHEAST OHIO AND MID OHIO VALLEY AROUND PKB MAY BE FASTER THAN
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    M    M    M    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z WEDNESDAY...
BRIEF IFR POSSIBLE IN FAST MOVING SHOWERS AND/OR THUNDERSTORMS
FRIDAY.

&&

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

&&

$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB/50
SHORT TERM...MZ
LONG TERM...TRM
AVIATION...50







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