National Weather Service Weather Forecast Office

Area Forecast Discussion

627
FXUS64 KHUN 030230 AAB
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
930 PM CDT WED OCT 2 2013

.UPDATE...
ADDED SHOWERS FOR THE REST OF THE EVENING/EARLY MORNING FOR MOST
AREAS NEAR/WEST OF I-65. ADJUSTED OVERNIGHT LOWS UPWARD A CATEGORY
AND INCREASED CLOUDS.

&&

.DISCUSSION...
A WEAK SHORT WAVE MOVING NORTHWARD ACROSS THE MID MISSISSIPPI AND
WEST OHIO RIVER VALLEYS WAS PRODUCING EXTENSIVE CLOUD COVER FROM
THE GULF COAST EAST OF THE MISSISSIPPI RIVER...NORTHWARD TO THE
GREAT LAKES. A FEW ECHOES (MAINLY VIRGA) WERE MOVING NORTHWARD ACROSS
PARTS OF NORTH/CENTRAL ALABAMA TO THE OHIO VALLEY. MID EVENING
TEMPERATURES WERE IN THE UPPER 60S TO LOW 70S...WITH LIGHT WINDS.

ALTHOUGH SURFACE OBSERVATIONS HAVE NOT INDICATED ANY RAINFALL
REACHING THE GROUND ACROSS THE GREATER HUNTSVILLE CFWA...HAVE ADDED A
SLIGHT CHANCE OF SHOWERS FOR MUCH OF OUR CENTRAL AND WESTERN AREAS
FOR THE REST OF THE EVENING... WITH THE RAIN TAPERING OFF FROM SOUTH
TO NORTH AFTER MIDNIGHT. DUE TO PLENTY OF LOWER LEVEL MOISTURE...WILL
LEAVE IN PATCHY FOG FOR THE VALLEYS AND LOCATIONS NEAR BODIES OF
WATER BEFORE DAYBREAK THU.

OTHER ADJUSTMENTS MADE WERE TO RAISE OVERNIGHT LOWS...GIVEN THAT THE
CLOUDS/MOISTURE SHOULD BE SLOW TO EXIT. WITH THAT BEING SAID...CLOUD
COVER SHOULD DIMINISH DURING THE LATE NIGHT. BUT FOG/MIST NOTED IN
THE FOG LOOP SHOULD BEGIN OVERSPREADING THE AREA FROM THE SOUTH.
UPDATED FORECASTS PRODUCTS HAVE BEEN SENT.

RSB

&&

.AVIATION...
/ISSUED 646 PM CDT WED OCT 2 2013/
FOR 00Z TAFS...
A WEAK UPPER LOW MOVING NORTHWARD ACROSS THE MID-MISSISSIPPI VALLEY
WILL BRING GENERALLY CLOUDY SKIES THROUGH THE PERIOD. THERE IS A
SLIGHT RISK FOR AN EVENING SHOWER IN THE VICINITY OF KMSL...GIVEN
DEEPER MOISTURE VALUES CLOSER TO THAT AIRPORT. WHILE AREA CEILING
VALUES SHOULD REMAIN ABOVE MVFR THRESHOLD...VISIBILITIES AT THE
KMSL TERMINAL COULD TEMPORARILY BECOME MVFR LATE TONIGHT/BEFORE
DAYBREAK THU.

RB

&&

.PREV DISCUSSION...
/ISSUED 140 PM CDT WED OCT 2 2013/
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW LIFTING NORTHWARD THRU
EASTERN AR. THIS LOW WAS CHARACTERIZED BY 1.5+ INCH PWS AND WAS
PRODUCING CLUSTERS OF TS WITH LOCALLY HEAVY RAINFALL. MUCH OF THIS
MOISTURE ALONG WITH THE LOW WILL BE DIRECTED SWIFTLY NORTH OF OUR
REGION INTO THE OH VALLEY TONIGHT INTO THURSDAY. THE UPPER RIDGE
AXIS WILL WEAKEN A BIT IN THIS PROCESS, BUT THE SFC/850 MB RIDGES
HOLD A GOOD GRIP OVER THE SE THRU SATURDAY. FORECAST SOUNDINGS DEPICT
A WARM NOSE BETWEEN 500-600 MB WHICH SHOULD ALSO LIMIT CAPE AND
SUPPRESS SHRA ACTIVITY OVERALL IN OUR REGION. THE EXCEPTION BEING
ISOLATED TERRAIN OR LAKE/RIVER BREEZE INDUCED CONVECTION. POPS WILL
BE LOWERED TO AROUND 10 PERCENT WITH A MENTION OF ISOLATED SHRA.

THE OTHER TWO MAIN FEATURES OF INTEREST ON IMAGERY WERE THE UPPER
TROF ENTERING THE WEST COAST AND THE TROPICAL WAVE IN THE WESTERN
CARIBBEAN. OBVIOUSLY IT IS EARLY TO SAY WITH HIGH CONFIDENCE
REGARDING THE TROPICAL WAVE OTHER THAN THERE IS A CONE OF UNCERTAINTY
ACROSS THE EASTERN GULF COAST, FOLLOWED BY A PROBABLE TRACK NE THRU
SERN AL/GA. THIS WOULD KEEP THE RFQ OUT OF OUR REGION AND REDUCE
CONCERN OF TORNADIC WEATHER. THE NAM HAS A TRACK FURTHER NW WHICH
COULD ENHANCE OUR LOW LEVEL SHEAR MORE. THE INTERACTION OF THE TROF
AND COLD FRONT SATURDAY NIGHT INTO SUNDAY WITH A TROPICAL AIRMASS
WOULD ENHANCE THE THREAT OF HEAVY RAINFALL. WILL GO WITH LIKELY TO
CATEGORICAL POPS, ESPECIALLY ON SUNDAY, AND CUT MOS TEMPS
SIGNIFICANTLY. A SWIFT EXIT OF THE TROF AND COLD FRONT IS PROGGED BY
THE GFS, BUT THE ECMWF SOLN SLOWS THE FRONTAL BOUNDARY, SO THESE
TRENDS WILL BE MONITORED CLOSELY. AGAIN, MUCH DEPENDS ON THE TRACK OF
THE TROPICAL WAVE AND HOW IT INTERACTS WITH THIS INCOMING TROF.

AK

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

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