National Weather Service Weather Forecast Office

Area Forecast Discussion

592
FXUS64 KHUN 231142 AAA
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
642 AM CDT THU MAY 23 2013

.UPDATE...
FOR 12Z TAFS

&&

.DISCUSSION...
/ISSUED 359 AM CDT THU MAY 23 2013/
A MORE AMPLIFIED FLOW WAS EVIDENT ACROSS THE GREATER NORTH AMERICAN
DOMAIN PER UPPER AIR DATA ANALYSIS. A BLOCKING PATTERN WAS SETTING
UP...WITH ITS UPPER LOWS OVER THE PACIFIC NW AND SOUTHERN GREAT
LAKES...AND UPPER RIDGING EXTENDING NORTHWARD FROM THE TEXAS COAST
TO THE SOUTHERN YUKON. CLOUDS ASSOCIATED WITH THE GREAT LAKES LOW
WERE ROTATING AROUND IT FROM THE CENTRAL PLAINS TO THE NORTHERN
APPALACHIANS. OTHER CLOUDS WERE ALONG A TROUGH EXTENDING SOUTHWARD
TO SOUTHERN GEORGIA. THOSE CLOUDS WERE A BIT DIFFICULT TO VIEW...DUE
TO A GOES-EAST SATELLITE OUTAGE. WHILE TECH SUPPORT HOPEFULLY WILL
RESTORE IT TO OPERATIONAL STATUS...GOES-14 IS BEING TAKEN OUT OF
STORAGE AND SHOULD BEGIN IMAGE/SOUNDING SCANS SOON.

WIDELY SCATTERED SHOWER ACTIVITY THAT AFFECTED THE TENNESSEE VALLEY
ON WED HAS MOVED WELL EAST OF HERE...NEAR THE EASTERN EDGE OF THE
KHTX PRECIP DETECTION RING. OTHERWISE...GENERALLY CLEAR SKIES WERE
PRESENT ACROSS THE TENNESSEE VALLEY. RESIDUAL MOISTURE FROM THE
RECENT RAINFALL AND STILL HIGH MOISTURE VALUES HAVE ALLOWED PATCHY
FOG TO BEGIN FORMING OVER PARTS OF THE DEEP SOUTH. OVERNIGHT LOW
TEMPS THUS FAR HAVE COOLED INTO THE LOWER 60S WITH LIGHT WINDS.

A COLD FRONT EXTENDED SSW FROM NORTHERN MICHIGAN TO FAR NW
TENNESSEE. THIS FRONT SHOULD MOVE ACROSS THIS REGION TODAY...
REACHING NW ALABAMA IN THE EARLY AFTERNOON...AND BE LOCATED SE OF
THE FORECAST AREA BY THE EARLY EVENING. FOR MOST OF THE AREA...NO
WEATHER OF CONSEQUENCE IS FORECAST TODAY. HOWEVER OVER ITS NORTHERN
EXTENT (CLOSER TO THE BETTER UPWARD FORCING)...SOME SHOWERS/T-STORMS
ARE POSSIBLE MAINLY ACROSS FAR NORTHERN ALABAMA (EAST OF HUNTSVILLE)
AND OUR MIDDLE TENNESSEE COUNTIES THIS AFTERNOON. LIMITED MOISTURE
AND INSTABILITY SHOULD KEEP STORMS ISOLATED IN COVERAGE AND NOT
EXPECTED TO BECOME SEVERE. AS THE FRONT MOVES SOUTH OF THE REGION
BY THE LATE AFTERNOON/EARLY EVENING...SHOWER ACTIVITY SHOULD END.

HIGH PRESSURE BUILDING TO THE SE FROM SOUTHERN CANADA WILL BRING
DRIER AND COOLER AIR ACROSS THE TENNESSEE VALLEY TO END THIS
WORKWEEK. AFTER HIGHS NEARING 90 THE OTHER DAY...HIGHS ON FRIDAY
WILL ONLY WARM INTO LOW/MID 70S...AND MID/UPPER 70S ON SATURDAY.
LOWS TEMPS SAT MORNING WILL COOL INTO THE MID 40S...AND BE IN THE
LOWER 50S SUN MORNING. DAILY HIGH/LOW TEMPERATURES HOWEVER WILL
RETURN TO SEASONABLE LEVELS BY SUNDAY...AND WARM TO ABOVE NORMAL
LEVELS FOR MEMORIAL DAY TO THE MID WEEK.

FURTHER DOWN THE ROAD...THE MODELS DIVERGE IN THEIR SOLUTIONS
CONCERNING RAIN CHANCES FOR THE FIRST HALF OF NEXT WEEK. THE
23/0000Z GFS STAYED ON A DRY PATH...WHILE THE ECMWF WAS HINTING AT
SHOWERS. WITH THE ECMWF HAVING A DECENT TRACK RECORD FURTHER OUT...
HAVE KEPT LOWER END POPS IN PLACE FOR MEMORIAL DAY AND ON TUESDAY.
THE ECMWF WAS SHOWING A FEED OF MOISTURE ROUNDING HIGH PRESSURE EAST
OF VA/NC...WHILE THE GFS KEPT THIS MOISTURE CLOSER TO THE GULF.

RSB

&&

.AVIATION...
FOR 12Z TAFS...SHALLOW AND VARIABLE FOG WILL CONTINUE TO IMPACT BOTH
TERMINALS THROUGH 14-1430Z. THIS WILL LEAD TO CONTINUED SWINGS IN
VISIBILITY FROM AROUND ONE MILE OR LESS TO ABOVE 6SM. AFTER
14Z...WINDS WILL INCREASE OUT OF THE WNW AND BECOME GUSTY TO AROUND
18KT. A FRONT WILL CROSS THE REGION AND SHIFT WINDS TO BE MORE
NORTHERLY BY THIS EVENING...BUT CHCS FOR RA/TSRA SHOULD LARGELY
REMAIN NE OF THE TERMINALS. LOW CIGS WILL THEN DEVELOP OVERNIGHT AND
LEAD TO MVFR CONDITIONS THROUGH THE END OF THE PERIOD.

CCC

&&

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

$$

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