Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 220738
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
338 AM EDT MON SEP 22 2014

.SYNOPSIS...
CANADIAN HIGH PRESSURE BUILDS IN THIS AFTERNOON AND TONIGHT.  IT
MOVES OFFSHORE MID WEEK AS LOW PRESSURE MOVES UP THE EAST
COAST...ONLY TO REBUILD OVER THE AREA LATE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
LOW LEVEL MOISTURE QUICKLY OVERSPREAD THE AREA THIS MORNING BENEATH
POST FRONTAL INVERSION IN WRAP AROUND CYCLONIC FLOW.  MODELS DO NOT
PICK UP ON ANY OF THE RAIN DOTTING THE MIDDLE AND UPPER OHIO VALLEYS
EARLY THIS MORNING...BUT DO REFLECT LIGHT RAIN SHOWERS ALONG THE
WESTERN SLOPES OF THE MOUNTAINS THIS MORNING.

FLOW QUICKLY BECOMES ANTICYCLONIC ALL THE WAY UP THROUGH THE MID
LEVELS TODAY...AS SFC HIGH PRESSURE BUILDS IN FROM THE W.  MOISTURE
BECOMES LIMITED TO A SHALLOW LAYER BENEATH THE INVERSION BEFORE
DRYING OUT ALTOGETHER BY THIS EVENING.

HIGH PRESSURE BUILDING INTO THE AREA WILL BRING A CLEAR...CALM NT
TONIGHT...RESULTING IN VALLEY FOG...ALONG WITH PATCHY FROST IN THE
BETTER SHELTERED VALLEYS OF THE NRN WV MOUNTAINS ALTHOUGH NOT
WIDESPREAD ENOUGH TO WARRANT AN ADVISORY.

HIGHS ARE BELOW GUIDANCE IN AIR MASS OF CANADIAN ORIGIN BENEATH THE
CLOUDS AND FRONTAL INVERSION TODAY...AND LOWS BETWEEN THE HIGHER MET
AND LOWER MAV TONIGHT.  THERE WAS LITTLE CHANGE NEEDED BUT DID USE
THE MET TO LOWER THE MIDDLE OHIO VALLEY A BIT TONIGHT WHILE MAKING
CERTAIN NOT TO RAISE LOWS ANYWHERE.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE...WITH A CLEAR SKY...COOL NIGHTS...AND WARM DAYS
EXPECTED IN THE SHORT TERM PERIOD. TEMPS WILL WARM NICELY ON
WEDNESDAY...AS UPPER HEIGHTS BUILD ACROSS THE EASTERN U.S. A FEW
CLOUDS MAY SEEP IN ACROSS EASTERN ZONES WEDNESDAY
NIGHT/THURSDAY...AS A LOW MOVES NORTHEAST ALONG THE COAST...BUT AREA
SHOULD REMAIN DRY. NO MAJOR CHANGES WERE NEEDED TO THE FORECAST.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL SLIDE TO THE EAST COAST BY THURSDAY AND
ALLOW A MODEST INCREASE OF LOW LEVEL MOISTURE FROM THE EAST AND
SOUTHEAST THROUGH SUNDAY. HOWEVER...UPPER RIDGING ALOFT WILL HOLD.
SO WHILE SOME LOW LEVEL MOISTURE WILL RETURN AS TIME GOES ON...THE
PROSPECTS OF ANY RAIN ARE VERY LOW AT BEST. THE LOW LEVEL MOISTURE
BANKING UP AGAINST EAST FACING SLOPES OF THE MOUNTAINS WILL ONLY
BRING INCREASED CLOUDS BY THE WEEKEND. OTHERWISE...SUNSHINE WILL
DOMINATE WEST OF THE MOUNTAINS. THERE WILL BE A SLOW WARMING TREND
WITH HIGHS TO AROUND 80 BY THE WEEKEND AND LOWS GENERALLY IN THE 50S
IN THE LOW LANDS.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
DRIER AIR TAKING FIRM CONTROL IN THE WAKE OF A COLD FRONT THAT
ROLLED THROUGH LATE SUNDAY.  THIS AND LIGHT NW SFC FLOW WILL
PRECLUDE FOG FOR THE MOST PART OVERNIGHT...BUT  A STRATOCU DECK
FORMING AND SPREADING SEWD INTO THE AREA OVERNIGHT BENEATH FRONTAL
INVERSION WILL LOWER TO MVFR FIRST FEW HOURS OF FCST...ALREADY
HAVING DONE SO AT PKB.  CIGS COULD LOWER TO NEAR THE TOP END OF IFR
IN THE MOUNTAINS AROUND DAYBREAK MON.

CIGS WILL GRADUALLY CLIMB AFTER DAYBREAK MON...BUT REMAIN IN MVFR
RANGE INTO MON AFTERNOON...EVEN THROUGH THE AFTERNOON IN THE NRN WV
MOUNTAINS...BEFORE BREAKING UP.

HIGH PRESSURE BUILDING INTO THE AREA MON NT WILL BRING CLEAR AND
CALM CONDITIONS...WITH MVFR FOG FORMING IN THE NRN WV MOUNTAIN
VALLEYS BY 06Z TUE.

LIGHT NW SFC FLOW THROUGH MON WILL BECOME CALM MON NT.  LIGHT TO
MODERATE NW FLOW ALOFT WILL DIMINISH MON AND BECOME LIGHT N MON NT.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING OF ONSET AND BREAK UP OF MVFR CIGS
OVERNIGHT AND MON MAY VARY...AS MAY LOWEST VALUES INCLUDING
BORDERLINE IFR IN THE MOUNTAINS MON MORNING.

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                              MON 09/22/14
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    M
HTS CONSISTENCY  H    H    H    M    M    M    M    M    M    M    M    M
BKW CONSISTENCY  H    H    H    M    M    M    L    M    M    H    H    M
EKN CONSISTENCY  H    M    M    L    L    L    L    L    M    M    H    M
PKB CONSISTENCY  H    H    M    M    M    H    H    H    M    M    M    M
CKB CONSISTENCY  H    H    H    M    H    H    H    H    H    H    H    H

AFTER 06Z TUESDAY...
IN THE CHILLY AIR...LOCAL IFR VALLEY FOG POSSIBLE EARLY TUESDAY
MORNING...ESPECIALLY ALONG RIVERS AND IN BETTER SHELTERED VALLEYS.

&&

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

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...TRM
SHORT TERM...SL
LONG TERM...JMV
AVIATION...TRM





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