-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 221908
AFDRAH

AREA FORECAST DISCUSSION...UPDATE.
NATIONAL WEATHER SERVICE
RALEIGH NC
207 PM EDT TUE APR 22 2014

UPDATED FOR FIRE WEATHER SECTION BELOW

.SYNOPSIS...A COLD FRONT WILL APPROACH FROM THE WEST THIS EVENING
THEN CROSS THE REGION TONIGHT. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST ON WEDNESDAY AND THURSDAY. ANOTHER COLD FRONT WILL
APPROACH FROM THE WEST ON FRIDAY.
&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 200 PM TUESDAY...

A SURFACE TROUGH WILL MOVE THROUGH THE AREA THIS AFTERNOON IN
ADVANCE OF AN UPPER LEVEL TROUGH AND ATTENDANT COLD FRONT TRACKING
THROUGH THE AREA THIS EVENING. DCVA AND LOW LEVEL CONVERGENCE
COMBINED WITH DIURNAL HEATING...WEAK MOISTURE ADVECTION AND MARGINAL
DIURNAL DESTABILIZATION WILL RESULT IN A POTENTIAL FOR SCATTERED
SHOWERS BETWEEN 18Z-23Z IN THE TRIAD AND 20-01Z IN THE TRIANGLE AND
COASTAL PLAIN...SIMILAR TO WHAT HIGH-RES CONVECTION ALLOWING MODELS
SUCH AS THE HRW-NMM INDICATE. ANYTHING MORE THAN ISOLATED THUNDER
APPEARS UNLIKELY GIVEN MARGINAL THERMODYNAMIC PROFILES.

THE POSTFRONTAL AIR MASS THAT FOLLOWS THE COLD FRONT IS STABLE AND
BRINGING IN LOW DEW POINTS FROM THE NORTHWEST WHICH WILL QUICKLY DRY
OUT THE AREA AND SUPPRESS ANY FURTHER PRECIPITATION BEHIND THE
FRONT. THERE IS A POTENTIAL FOR LINGERING CLOUDS BEHIND THE FRONT AS
THE DRY AIR IS MIXED FROM ALOFT DOWN TO THE SURFACE. ANY LINGERING
CLOUDS WILL CLEAR OUT SOON AFTER THE COLD FRONTAL PASSAGE LEADING TO
CLEAR SKIES TONIGHT. -SSR/VINCENT
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&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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AS OF 207 PM TUESDAY...

...SEE FIRE WEATHER SECTION BELOW FOR POTENTIAL WEATHER HAZARDS FOR
WEDNESDAY AFTERNOON AND EVENING...

RATHER WINDY CONDITIONS ARE EXPECTED WEDNESDAY AS THE PRESSURE
GRADIENT REMAINS TIGHT. STRONG COOL AND DRY ADVECTION WILL BE DRIVEN
BY NORTHWEST WINDS AT 15-20 MPH WITH GUSTS TO 30 MPH. THIS DRYING
PROCESS ALONG WITH THE WINDS AND LOW RELATIVE HUMIDITY VALUES
EXPECTED MAY LEAD TO A CRITICAL FIRE WEATHER DAY WEDNESDAY. WINDS
WILL DIMINISH TO LESS THAN 10 MPH WEDNESDAY NIGHT AS THE HIGH
BECOMES POSITIONED OVERHEAD LATE. A RATHER QUICK RETURN SW FLOW IS
EXPECTED TO DEVELOP THURSDAY (BUT WITH MUCH LESS VELOCITY 8-12 MPH
DURING THE AFTERNOON). THIS INFORMATION WILL BE COLLABORATED WITH
THE FORESTRY OFFICIALS.

OTHERWISE... TEMPERATURES SHOULD AVERAGE 5-10 DEGREES BELOW THE 30
YEAR NORMALS WEDNESDAY THROUGH THURSDAY. SENSIBLE WEATHER... SUNNY
AND WINDY WEDNESDAY. HIGHS IN THE UPPER 60S TO MID 70S (SE). CLEAR
AND CHILLY WEDNESDAY NIGHT. LOWS IN THE UPPER 30S TO LOWER 40S.
MOSTLY SUNNY AND MILD THURSDAY. HIGHS IN THE LOWER 70S. BECOMING
MOSTLY CLOUDY THURSDAY NIGHT. LOWS IN THE UPPER 40S NE TO MID 50S.
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&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 130 PM TUESDAY...

TRAILING END OF A SHORTWAVE AND ASSOCIATED WEAK FRONT WILL SWEEP
ACROSS THE AREA EARLY FRIDAY. MOISTURE ADVECTION IS MINIMAL WITH LOW
LEVEL WESTERLY FLOW ACROSS THE GULF...BUT DIURNAL TIMING WILL BE
FAVORABLE...WITH HIGHS APPROACHING 80...TO PRODUCE RESPECTABLE
INSTABILITY (CAPES >1000J) WHICH WILL SUPPORT SCATTERED CONVECTION.
FRONT REACHES THE COAST EARLY FRIDAY NIGHT AND CONVECTION WILL DIE
OFF QUICKLY AFTER SUNSET WITH SKIES BECOMING MOSTLY CLEAR. MINS WILL
REMAIN MILD...IN THE MID 50S. SATURDAY WE WILL REMAIN MILD...NEAR 80
AGAIN...DUE TO WESTERLY LOW LEVEL FLOW AHEAD OF A STRONGER...BUT
DRY...BACKDOOR COLD FRONT WHICH WILL BE PRESSED SLOWLY SOUTH OF THE
AREA SATURDAY NIGHT. A COOLER AIRMASS WILL BE IN PLACE BY SUNDAY AS
HIGH PRESSURE ORIGINATING OVER THE NORTHERN GREAT LAKES SETTLES
SOUTH DOWN THE EAST COAST. HIGHS SUNDAY AND MONDAY WILL STALL IN THE
LOW TO MID 70S.

UNCERTAINTY AS TO THE EVOLUTION AND DETAILS OF THE NEXT SIGNIFICANT
SYSTEM EARLY NEXT WEEK...WHETHER WE LOCK IN THE COOL AIR AND GET
SOME OVERRUNNING OR WHETHER ITS SCOURED OUT AND WE WARM UP
SIGNIFICANTLY TUESDAY. REGARDLESS...THERE WILL BE INCREASING CHANCES
OF SHOWERS MONDAY NIGHT AND TUESDAY...WILL INTRODUCE IN THE CHANCE
CATEGORY AND LET THE FORECAST EVOLVE. WILL MAINTAIN HIGHS TUESDAY IN
THE 70S.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 1145 AM TUESDAY...

VFR CONDITIONS WILL LARGELY PREVAIL THROUGH THE TAF PERIOD. A SHORT
PERIOD OF MVFR CONDITIONS WILL BE POSSIBLE IN ASSOC/W ISOLD TO SCT
SHOWER ACTIVITY DEVELOPING IN ADVANCE OF AN APPROACHING FRONT THIS
AFTERNOON AND EVENING. A TEMPO GROUP WILL BE INCLUDED TO ACCOUNT FOR
SUCH A POTENTIAL.

LOOKING AHEAD: VFR CONDITIONS WILL RULE THROUGH THURSDAY IN THE WAKE
OF THE COLD FRONTAL PASSAGE TONIGHT. SUB-VFR CEILINGS WILL BE
POSSIBLE IN ASSOC/W SOUTHERLY RETURN FLOW THU NIGHT...IN ADVANCE OF
THE NEXT COLD FRONT CROSSING THE REGION FROM THE WEST ON FRIDAY...
FOLLOWED BY VFR CONDITIONS AGAIN ON SAT. -VINCENT

&&

.FIRE WEATHER /WEDNESDAY INTO WEDNESDAY EVENING...
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AS OF 207 PM TUESDAY...

...ENHANCED FIRE DANGER STATEMENT WILL BE ISSUED FOR WEDNESDAY
FOR 900 AM THROUGH 700 PM...

NORTHWEST WINDS AT 15 TO 20 MPH WILL GUST TO 30 BEHIND A COLD FRONT
WEDNESDAY AFTERNOON INTO EARLY WEDNESDAY EVENING. LOW MINIMUM
RELATIVE HUMIDITIES OF 20 TO 25 PERCENT CAN BE EXPECTED WEDNESDAY
AFTERNOON. FINE FUEL MOISTURE LEVELS WILL DRY OUT. IN COORDINATION
WITH WAKEFIELD AND BLACKSBURG - AND THE FORESTERY OFFICIALS... WE
WILL ISSUE AN INCREASED FIRE DANGER STATEMENT FOR WEDNESDAY.

.RAH WATCHES/WARNINGS/ADVISORIES... NONE.
-- End Changed Discussion --

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...VINCENT
SHORT TERM...BADGETT
LONG TERM... MLM
AVIATION...VINCENT
FIRE WEATHER...BADGETT