Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 261417
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1017 AM EDT TUE MAY 26 2015

.SYNOPSIS...
THE AREA WILL REMAIN IN A SOUTH TO SOUTHWEST FLOW OF WARM AND
HUMID AIR. AN UPPER LEVEL TROUGH SLOWLY LIFTS THROUGH TODAY
THROUGH THURSDAY. LOW PRESSURE APPROACHES LATE IN THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
SENT A QUICK UPDATE TO TRIM POPS A BIT FOLLOWING LATEST RADAR
IMAGES. RAINFALL ACTIVITY IS VERY LIMITED ATTM. HOWEVER...KEPT
LIKELY POPS AS EXPECTED CONVECTION SHOULD AFFECT PORTIONS OF
SOUTHEAST OH...AND NORTHEAST KY LATER THIS AFTERNOON AND EVENING.
ALSO...TWEAKED HOURLY TEMPERATURES PER LATEST SFC OBS.

PREVIOUS DISCUSSION BELOW...

630 AM UPDATE...
THERE REMAIN SOME QUESTION AS TO HOW MUCH SHRA ASSOCIATED WITH
MORNING MID LEVEL WAVE COME TOGETHER IN TERMS OF MEASURABLE
RAINFALL. KEPT THE SMALL LIKELY POPS MOVING NEWD THROUGH FCST AREA
THIS MORNING BUT LOWERED THE CHANCE FOR THE UNDER.

PREV DISCN...
WARM MOIST AIR ON THE MOVE KEEPS THE CHANCE FOR THUNDERSTORMS IN
THE FCST THIS PERIOD. AFTERNOON INSTABILITY IS LIMITED TO A KG PER
KG OR LESS THIS AFTERNOON ON ACCOUNT OF MORNING CLOUD COVER AND
PRECIPITATION...AS PW VALUES RESIDE MAINLY BETWEEN 1.5 AND 1.75
INCHES.

OTHERWISE WEAK RIPPLES IN THE UPPER LEVEL SW FLOW OUT AHEAD OF A
S/W TROUGH DRIFTING NEWD FROM THE CENTRAL PLAINS THIS MORNING...TO
THE MIDWEST WED MORNING...WILL DRIVE CONVECTION TIMING. ONE RIPPLE
WAS PRODUCING AN AREA OF SHOWERS FROM THE SRN APPALACHIANS TO ERN
KY EARLY THIS MORNING AND SHOULD MOVE ACROSS THE FCST AREA THIS
MORNING.

THE MAIN S/W TROUGH AXIS THEN LIFTS NEWD AND IS REPLACED
BY ANOTHER...THE LARGER FEATURE EFFECTIVELY MUCH SLOWER THAN THE
SMALLER RIPPLES WITHIN THE FLOW. THE TAIL END OF THE ORIGINAL S/W
TROUGH APPROACHES THE FCST AREA FROM THE W LATE TODAY AND THEN
CROSSES TONIGHT. SHOWERS AND THUNDERSTORMS ARE LIKELY TO PROGRESS
GENERALLY FROM W TO E ACROSS THE FCST AREA TONIGHT.

THE STRONG MID LEVEL FLOW ASSOCIATED WITH THIS FEATURE COUPLED
WITH THE LATE DAY INSTABILITY...COULD LEAD TO STRONG TO DAMAGING
WIND GUSTS IN THUNDERSTORMS OVER THE MIDDLE OHIO VALLEY LATE
TODAY...ESPECIALLY IF ONE IF FAR ENOUGH N AND W TO AVOID MUCH OF
THE CLOUDS AND SHOWERS ASSOCIATED WITH THE DISTURBANCE MOVING
THROUGH THIS MORNING. WILL CONTINUE THE HWO MENTION IN LINE WITH
THE NEW SWODY1.

LOCALLY HEAVY DOWNPOURS ARE ALSO POSSIBLE...BUT THE STORMS WILL BE
ON THE MOVE...LIMITING ANY HIGH WATER TO THE ACUTE POOR DRAINAGE
VARIETY.

BLENDED IN MOSGUIDE FOR SLIGHTLY LOWER HIGHS ESPECIALLY E
TODAY...STILL AT THE HIGH END OF THE GUIDANCE ENVELOP. LOWS
TONIGHT CLOSE TO GUIDANCE AND ACCEPTED.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ACTIVE SUMMER LIKE PATTERN CONTINUES IN THE SHORT TERM PERIOD.
UPPER RIDGE WILL BE OFF THE EAST COAST...WITH A SOUTHWESTERLY FLOW
ACROSS THE AREA ON WEDNESDAY. WILL CONTINUE TO HAVE A WARM AND
HUMID AIR MASS IN PLACE...AND THIS ALONG WITH SEVERAL UPPER
DISTURBANCES MOVING THROUGH THE FLOW...WILL CONTINUE TO SEE
SHOWERS AND THUNDERSTORMS...PARTICULARLY DURING DAYTIME HEATING
HOURS. ANY SHOWERS/STORMS WILL BE CAPABLE OF HEAVY DOWNPOURS IN
THE HUMID ATMOSPHERE. THE AREA IS HIGHLIGHTED IN A MARGINAL FOR
SEVERE WEATHER ON WEDNESDAY. THE BEST LOCATION FOR SEVERE LOOKS
TO BE TO THE WEST AND NORTH OF THE CWA...WHERE BETTER
INSTABILITY...SHEAR...AND UPPER DYNAMICS WILL EXIST. WILL HOWEVER
MENTION THE MARGINAL IN THE HWO AS AN ISOLATED STORM GOING SEVERE
IN THE UNSTABLE CONDITIONS CANT BE COMPLETELY RULED OUT.

AN UPPER SHORTWAVE AND SURFACE COLD FRONT WILL APPROACH THE CWA
WEDNESDAY NIGHT...BEFORE STALLING OR WASHING OUT ACROSS THE
AREA. THUS...THERE APPEARS TO BE NO RELIEF IN THE SHORT TERM
PERIOD TO THE HEAT AND HUMIDITY. IN ADDITION...HEIGHTS WILL BUILD
DURING THE DAY ON THURSDAY BEHIND THE DEPARTING SHORTWAVE...WITH
MAX TEMPERATURES ON THURSDAY A FEW DEGREES WARMER THAN WEDNESDAY.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
FOLLOWED ALONG WITH WPC GUIDANCE THROUGH THE LONG TERM. FRONT
CROSSES LATE IN THE PERIOD WITH SOME COOLING AND DRYING NORTH AND
WEST. STILL NOT CONFIDENT ENOUGH TO DROP POPS COMPLETELY OUT OF
THE FORECAST SO LATE IN THE PERIOD...WITH FRONT BEING IN THE
AREA. THUS...SUMMER LIKE BROAD BRUSH OF CHC POPS CARRY THROUGH
MUCH OF THE FORECAST PERIOD.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
WARM AND HUMID AIR IN PLACE...AND RIPPLES IN THE UPPER LEVEL SW
FLOW...SPELL ROUNDS OF SHOWERS AND THUNDERSTORMS. THIS KEEPS
CONFIDENCE AT MEDIUM...WITH UNCERTAINTY ON THE COVERAGE OF SHOWERS
AND EMBEDDED THUNDERSTORMS FORMING/MOVING UP FROM THE S EARLY THIS
MORNING...PLUS TIMING NEW ROUNDS OF CONVECTION ARRIVING FROM THE
WSW LATE IN THE DAY TUE.

HAVE CIGS MAINLY ATOP MIXING LAYER 4-5 KFT AND PREVAILING VFR
VSBY. A SHORT PERIOD OF MVFR IS STILL POSSIBLE AS SHOWERS MOVE
THROUGH THIS MORNING...AND THUNDER IS POSSIBLE BUT NOT LIKELY.
AFTER A RELATIVE AFTERNOON LULL...ANOTHER ROUND OF CONVECTION IS
LIKELY TO ARRIVE FROM THE W LATE TODAY OR THIS EVENING.
THUNDERSTORMS ASSOCIATED WITH THIS CONVECTION MAY PRODUCE STRONG
WIND GUSTS...ESPECIALLY OVER THE MIDDLE OHIO VALLEY. BRIEF IFR IS
POSSIBLE BENEATH ANY THUNDERSTORM LATE TODAY OR TONIGHT.

SFC FLOW WILL BE LIGHT S TO SW BY DAY AND S TO SE BY NT...WITH
MODERATE SW FLOW ALOFT.

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING OF CONVECTION MAY DIFFER FROM
FORECAST. THERE MAY BE IFR IN SHOWERS...THUNDERSTORMS AND RAIN
INDUCED FOG OVERNIGHT TONIGHT.

.AFTER 00Z WEDNESDAY...LOCAL IFR IN SHOWERS/STORMS...AND RAIN
INDUCED LOW STRATUS AND FOG INTO WED MORNING. IFR MAY LINGER
IN THE MOUNTAIN COUNTIES WED AFTERNOON.

&&


WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

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

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...ARJ/TRM
SHORT TERM...SL
LONG TERM...KMC
AVIATION...TRM


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