Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 260130
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
928 PM EDT FRI JUL 25 2014

.SYNOPSIS...
FLOW TURNS SOUTHWEST BRINGING STRONG WARM AIR ADVECTION SATURDAY.
A SERIES OF DISTURBANCES IN A WEST/NORTHWEST FLOW ALOFT WITH
ROUNDS OF CONVECTION MAINLY SATURDAY NIGHT THRU SUNDAY NIGHT.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
CLOUDS ARE COMING IN A BIT FASTER THAN MODELS INDICATED.
THEREFORE...WILL UPDATE SKY COVER THIS EVENING ACCORDINGLY.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
SURFACE SOUTHERLY FLOW AND WESTERLY ALOFT WILL BRING MODEST WARM AIR
ADVECTION TO THE REGION SATURDAY NIGHT INTO SUNDAY. WINDS AT H85
BECOME ABOUT 45 KNOTS OUT OF THE SOUTHWEST AHEAD OF AN APPROACHING
COLD FRONT.

A BROAD UPPER LEVEL LOW PRESSURE SYSTEM CENTERED NORTH OF THE GREAT
LAKES REGION EXTENDS SOUTH WITH A SERIES OF VORTICITY LOBES NOTICED
AT H5 PASSING OVER OH VALLEY AND WV. THE FIRST AND WEAKER WAVE MOVES
THROUGH OVERNIGHT HOURS OF SATURDAY NIGHT. THE SECOND BUT STRONGER
VORTICITY MAXIMA MOVES ACROSS DURING THE DAY SUNDAY WITH ADDITIONAL
VORTICITY LOBES PASSING THROUGH MONDAY.

MODELS ARE IN DESCENT AGREEMENT WITH THE TIMING OF CONVECTION
REACHING OR DEVELOPING OVER OUR AREA...ALTHOUGH SUBTLE DIFFERENCES
ARE NOTICED ON THE LOCATION OF THE STRONGEST PCPN.

THE GFS AND ECMWF SHOW THE ARRIVAL OF TWO MID LEVEL WAVES...ONE
APPROACHING SOUTHEAST OH BY 00Z AND THE SECOND BY 06Z SUNDAY. SFC
BASED CAPE INCREASES TO 1800 J/KG BY 12Z SUNDAY...AND EXCEEDING
2500 J/KG SUNDAY AFTERNOON ACROSS THE TRI STATE AREA...EXTENDING
NORTHEAST ACROSS WV AND SOUTHEAST OH. MODELS SUGGEST DEEP LAYERED
SHEAR EXCEEDING 60 KNOTS AND PWATS AROUND 2 INCHES SUNDAY AFTERNOON.
HELICITY VALUES EXCEED 300 M2/S2 BY THE SAME TIME PERIOD. THESE
INGREDIENT ARE FAVORABLE FOR STORMS TO BECOME SEVERE WITH
THERMODYNAMIC AND DYNAMIC INSTABILITY. CONSEQUENTLY...THERE IS A
SLIGHT RISK FOR SEVERE THUNDERSTORMS ACROSS SOUTHEAST OH...NORTHEAST
KY AND ALL OF WV FOR SUNDAY.

WITH GOOD CONSENSUS AMONG SYNOPTIC MODELS AND SREF INDICATING 60
PERCENT POPS MAINLY ACROSS THE NORTHERN THIRD OF OUR
CWA...CONFIDENCE HAS INCREASED AND DECIDED TO INCREASE POPS AS WELL
FOR SUNDAY. MENTIONED DAMAGING WINDS AND HAIL IN THE WEATHER GRIDS
ALONG WITH HEAVY RAIN PER THE AFOREMENTIONED PARAMETERS.

IN ADDITION...HPC HAVE PORTIONS OF SOUTHEAST OH...NORTHEAST KY AND
THE ENTIRE AREA OF WV UNDER HIGH PROBABILITY OF EXCESSIVE RAINFALL.
BACKWARD CORFIDI VECTOR MAGNITUDE INCREASE CONSIDERABLY ON SUNDAY
AFTERNOON. WITH PWATS RANGING AROUND 2 INCHES...AND THE NATURE OF
THE SEVERE THUNDERSTORMS...WATER PROBLEMS MAY RESULT WITH REPETITIVE
PERIODS OF HEAVY RAINFALL. A FLASH FLOOD WATCH MAY BE REQUIRED FOR
SUNDAY AND EARLY MONDAY.

LINGERING SHOWERS OR STORMS CAN NOT BE RULED OUT SUNDAY NIGHT INTO
MONDAY AS THE BROAD UPPER LOW CONTINUES TO PUSH VORTICITY MAXIMA
ACROSS THE AREA. CODED LOW CHANCE POPS FOR SUNDAY NIGHT INTO MONDAY.

DESPITE OF WARM AIR ADVECTION ALOFT...EXPECT MILD TEMPERATURES DUE
TO CLOUD COVER AND COOLING SHOWERS EFFECTS. WENT GENERALLY WITH THE
CONSENSUS MOS GUIDANCE WITH SOME TWEAKS. KEPT WARMER TEMPS FOR A
MUGGY SUNDAY NIGHT. LOW TURN NORTHWEST BY MONDAY BRINGING COOLER
PLEASANT TEMPERATURES DURING THE FIRST HALF OF THE WEEK.

CONDITIONS IMPROVE MONDAY AND MONDAY NIGHT. AS THE COLD FRONT
EXITS...WITH PRECIP DECREASING FROM WEST TO EAST AND MUCH COOLER
TEMPERATURES OVERSPREADING THE AREA.&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
HIGH PRESSURE BEHIND THE COLD FRONT TAKES CONTROL LATER MONDAY NIGHT
THROUGH THE MIDDLE OF NEXT WEEK WITH NEAR NORMAL TEMPERATURES.

BLENDED HPC WITH PREVIOUS FORECAST NUMBERS AS THEY LOOK
REPRESENTATIVE UNDER HIGH PRESSURE AND SLIGHTLY COOLER NORTHERLY
FLOW.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
|* ADD DISCUSSION HERE. *|

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
A VORTICITY LOBE WILL BE MOVING ACROSS THE AREA OVERNIGHT. EXPECT
VFR CLOUDS WITH THIS SYSTEM. SOME PATCHY DENSE RIVER FOG IS POSSIBLE
LATE TONIGHT IN THE MOUNTAIN RIVER VALLEYS...BUT WITH CLOUDS MOVING
IN...EXPECT THE FOG TO LIFT EARLY. A CUMULUS DECK CAN BE EXPECTED IN
WV AND VA ON SATURDAY.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...

FORECAST CONFIDENCE: HIGH.

ALTERNATE SCENARIOS: TIMING...COVERAGE AND DENSITY OF FOG LATE
TONIGHT COULD 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.

UTC 1HRLY       20   21   22   23   00   01   02   03   04   05   06   07
EDT 1HRLY       16   17   18   19   20   21   22   23   00   01   02   03
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    M    M    H    L    L
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 00Z SUNDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION SATURDAY NIGHT INTO SUNDAY
NIGHT.

&&

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

&&

$$
SYNOPSIS...ARJ/50
NEAR TERM...RPY
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...RPY










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