-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 131044
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
644 AM EDT MON MAY 13 2013

.SYNOPSIS...
UPPER LEVEL TROUGH AXIS EXITS BY MID DAY. WARM FRONT DEVELOPS
TUESDAY BRINGING WARMER TEMPERATURES THROUGH TUESDAY NIGHT. MUCH
WARMER WEDNESDAY ACCOMPANIED WITH SHOWERS AND THUNDERSTORMS LATE.

&&

.NEAR TERM /THROUGH TONIGHT/...
A VORTICITY LOBE IN THE PERIPHERY OF THE PARENT UPPER LEVEL LOW
OVER THE GREAT LAKES...IS PRODUCING A CLOUD DECK ACROSS THE OH
VALLEY AND WV TO LAST THROUGH AT LEAST MID MORNING.

THEREFORE...CANCELLED FROST ADVISORY FOR THE LOWLANDS...AND FREEZE
WARNING FOR THE HIGHLANDS AND EXTREME NORTHERN PORTIONS OF
SOUTHEAST OH AS CLOUD COVER IS PREVENTING THE RADIATIONAL COOLING
NEEDED TO DROP TEMPERATURES TO THE CORRESPONDING THRESHOLDS. THIS
CLOUD DECK IS AROUND 8 KFT AND WILL CONTINUE TO SPREAD EAST ACROSS
THE AREA THROUGH THE EARLY MORNING HOURS.

A HIGH PRESSURE BUILDS IN FROM THE WEST PROVIDING DRY AND COOL CONDITIONS
UNDER NORTHWEST FLOW.

WITH MORE CONFIDENCE FOR CLEAR SKIES AND CALM FLOW LATE TONIGHT
AND EARLY TUESDAY MORNING...ISSUED A FREEZE WATCH FOR OUR
NORTHEAST QUADRANT COUNTIES. EXPECT RADIATIONAL COOLING TO DROP
TEMPERATURES INTO THE UPPER 20S...POSING A THREAT OF KILLING
SPROUTING VEGETATION.

USED THE BIAS CORRECTED SREF BLENDED WITH NAM FOR HIGHS
TODAY...AND WITH THE BIAS CORRECTED CONRAII WITH FEW TWEAKS DOWN
ACROSS THE NORTHEAST.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
OVERALL NOT MUCH CHANGE WITH REGARD TO TUESDAY/S FORECAST. NORTHWEST
FLOW ALOFT CONTINUES OVER AREA WITH UPPER TROUGH OVER NORTHEAST
CONUS WITH UPPER RIDGING OVER THE GREAT LAKES REGION. SFC WINDS
RETURN OUT OF THE SOUTH AS SFC HIGH PRESSURE CONTINUES TO SLIDE OFF
THE EAST. LATEST 18Z GFS40 DEPICTING SOME MEAGER PRECIP ACROSS FAR
NORTHERN ZONES...WITH SLIGHTLY MORE LLVL MOISTURE AVAILABILITY
VERSUS NAM12 AND ECMWF. STILL HOWEVER...GFS MOISTURE DEPTH IS ONLY
ABOUT 3KFT WITH NO INSTABILITY AND CONFINED ABOVE 800MB. GIVEN THE
DRY AIR BELOW 800MB...CAN/T SAY THAT IT WOULD BE TOTALLY OUT OF
THE REALM OF POSSIBILITY THAT AN ISOLATED SPRINKLE MIGHT REACH THE
GROUND BUT CERTAINLY NOT EXPECTING ANYTHING MEASURABLE AND WILL
CONTINUE DRY FORECAST. OVERNIGHT TUESDAY NIGHT NW FLOW ALOFT
CONTINUES BUT BEGINS TO FLATTEN A BIT AS THE UPPER RIDGE MOVES
CLOSER. ONE VORT MAX PROGGED NEAR THE NORTHERN WV PANHANDLE AT 00Z
WED BUT WITH LITTLE MOISTURE TO WORK WITH...WITH ANOTHER WEAKER VORT
MAX MOVING OVER THE RIDGE AXIS ACROSS SOUTHERN INDIANA TOWARDS DAWN
WED. TROUGH AT 850MB STILL LOCATED NEAR OR JUST WEST OF FORECAST AREA
BY 12Z WED WITH STRONG WARM ADVECTION CONTINUING. BEST OVERALL LIFT
NORTH AND NORTHEAST OF THE AREA. LOW LEVEL MOISTURE PER LATEST
NAM/GFS SOUNDINGS STILL VERY LIMITED HOWEVER...EVEN OVER NORTHEAST.
NO PRECIP EXPECTED WITH THE WESTERN APPROACHING IMPULSE WITH LITTLE
LLVL MOISTURE TO WORK WITH. WILL LEAVE SLIGHT CHANCE POPS ACROSS
HIGHER TERRAIN OF NORTHEAST MOUNTAINS BUT LIMIT TO SPRINKLES MENTION
FOR LOCATIONS UNDER 2.5KFT SUCH AS EKN AND CKB WITH DEPTH OF
MOISTURE HERE STILL ONLY ABOUT 1500-2000FT.

BY WEDNESDAY WEAKENING 500MB RIDGE AXIS CONTINUES EAST AND IS EAST
OF FORECAST AREA BY 00Z THU...WITH RESULTING ZONAL FLOW ALOFT. 850MB
THERMAL RIDGE WITH TEMPS AROUND 17C-18C PUSHES ACROSS AREA DURING
THE AFTERNOON. RESULTANT 925MB TEMPS AROUND 23-24C SUPPORT TEMPS OF
AROUND 88F-90F LOWLANDS AND AS SUCH HAVE CONTINUED TREND OF NUDGING
TEMPS UPWARD FOR WED AFTERNOON. HAVE STOPPED SHORT OF THE 90F DEGREE
MARK FOR THIS PACKAGE...BUT SHOULD LATEST NAM12 VERIFY CERTAINLY 90F
FOR PARTS OF THE AREA IS POSSIBLE. NO PRECIP EXPECTED FOR WEDNESDAY
DURING THE DAY HOURS WITH NO REAL LARGE-SCALE FORCING MECHANISMS
NOTED...BUT WILL SEE INCREASING CLOUD COVER DURING THE AFTERNOON
HOURS ACROSS THE NORTHERN ZONES. WEDNESDAY NIGHT WILL SEE INCREASING
CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE NW ZONES BEGINNING
00Z THU AS DIFFUSE FRONT NEARS NORTHERN ZONES...BUT PARTICULARLY
AFTER 06Z THU AS MOISTURE INCREASES IN ADVANCE OF AN APPROACHING S/W
TROUGH PUSHING EASTWARD ACROSS THE MID-OHIO VALLEY. DEPENDING ON
DEWPOINTS REALIZED...SOME STORMS MAINLY BTWN 00Z-06Z THU MAY BE ON
THE STRONG SIDE WITH EL/S BTWN 35-38KFT AND 0-6K SHEAR AROUND
30-35KTS PROGGED...WITH SB/MU CAPE AROUND 1200-1500J/KG ACROSS THE
NW ZONES. CAPE PROFILE IN THE HAIL GROWTH ZONE STILL RELATIVELY
NARROW HOWEVER.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
IN THE WAKE OF THE WARM FRONT...STILL HAVE A STRONG WARM SURGE
MOVING IN DURING THE DAY ON WEDNESDAY.  THE PLUS 24C 850 MB AIR OVER
IOWA TUESDAY NIGHT DAMPENS TO ABOUT PLUS 16/17C FOR OUR VICINITY
BY 00Z THURSDAY.  SO HAVE SOME MID 80S MENTIONED IN THE USUAL WARMER
SPOTS.

THINKING ANY LEFTOVER SHOWERS WITH WARM FRONT SHOULD BE EXITING OUR
NE COUNTIES WEDNESDAY MORNING. DO THINK THERE COULD BE
SHOWERS/THUNDERSTORMS REDEVELOP JUST TO OUR NORTH WEDNESDAY
AFTERNOON OR EARLY EVENING...SAY ACROSS NORTHERN OHIO INTO WESTERN
PENNSYLVANIA.  WE TRIED TO SAG SOME OF THAT ACTIVITY SOUTHEAST
OVERNIGHT WEDNESDAY NIGHT.

WHAT IS LEFT OF THE DAMPENING SOUTHERN STREAM 500 MB TROF REACHES US
THURSDAY AFTERNOON AND THURSDAY NIGHT...SO ADD MOISTURE FURTHER
SOUTH...OF THAT FRONT.

HAVE OUR HIGHEST POPS THURSDAY AFTERNOON INTO THURSDAY NIGHT FOR
MOST OF CWA...BUT COULD NOT GO LIKELY YET.

THE FRONTAL ZONE FROM THE MIDWEST INTO THE LOWER GREAT LAKES...UPPER
OHIO VALLEY...MAY OSCILLATE NORTH AND SOUTH INTO THE WEEKEND...BUT
REMAIN BASICALLY QUASI-STATIONARY. SO AT THIS DISTANCE IN TIME...HAD
TO LEAVE A MENTION OF SHOWERS OR THUNDERSTORMS.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
AN UPPER LEVEL LOW PRESSURE SYSTEM ACROSS THE GREAT LAKES WILL
PRODUCE VORTICITY LOBES ON ITS PERIPHERY...EXTENDING SOUTH INTO
THE OH VALLEY AND WV OVERNIGHT. THIS VORT MAXES WILL PRODUCE A
CLOUD DECK BETWEEN 7 TO 8 KFT...WITH SMALL POCKETS OF CLEAR
SKIES. THEREFORE...EXPECT VFR CONDITIONS THROUGH THE PERIOD.

A HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY TO CONTINUE
WITH DRY CONDITIONS FOR THE MOST PART. LOW CHANCES FOR PCPN EXIST
ACROSS THE NORTHERN HALF OF THE AREA AND THE EASTERN MOUNTAINS
THSI AFTERNOON. BUT CHANCES ARE TOO LOW TO BE INCLUDED IN TAFS.

RELATIVELY LIGHT SURFACE WINDS FOR THIS MORNING...WITH OCCASIONAL
GUSTS DURING AFTERNOON.

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

FORECAST CONFIDENCE...HIGH

ALTERNATE SCENARIOS: NONE.

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       11   12   13   14   15   16   17   18   19   20   21   22
EDT 1HRLY       07   08   09   10   11   12   13   14   15   16   17   18
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 12Z TUESDAY...
NO WIDESPREAD IFR EXPECTED.
-- End Changed Discussion --

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZE WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
     WVZ010-011-019-020-030>032-037>040-046-047.
OH...NONE.
KY...NONE.
VA...NONE.

&&

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