Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 051112
AFDHUN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
612 AM CDT THU MAY 5 2016

.UPDATE...
FOR 12Z TAFS

&&

.DISCUSSION...
/ISSUED 246 AM CDT THU MAY 5 2016/
AN UNSEASONABLY STRONG (ALMOST WINTER LIKE) LOW PRESSURE SYSTEM IS
CURRENTLY LOCATED OVER THE OH VALLEY AND WILL DROP SOUTHEAST TOWARDS
THE REGION TODAY. EXPECT THE SCATTERED SHOWERS ON THE BACKSIDE OF THE
SYSTEM TO FOLLOW ALONG AS THE LOW DROPS SOUTH. THE QUESTION IS
WHETHER OR NOT THEY MAKE IT INTO THE AREA OR NOT. ALL THE LATEST
HIRES GUIDANCE (NSSLWRF, NCAR ENSEMBLES, HRRR, AND OTHERS) KEEP MOST
SHOWER ACTIVITY TO OUR EAST WITH SOME CLIPPING OUR FAR EASTERN
ZONES. THIS SEEMS REASONABLE GIVEN THE MOST RECENT FORECAST SOUNDINGS
AND EXTRAPOLATING THE CURRENT SHOWER ACTIVITY OUT IN TIME. SO, HAVE
PULLED BACK THE ALREADY LOW POPS A BIT TO ONLY INCLUDE OUR FAR
EASTERN ZONES.

THE MAIN IMPACT THIS SYSTEM WILL HAVE ON THE TN VALLEY TODAY IS THE
VERY BREEZY WINDS THAT ARE GOING TO ACCOMPANY THE SYSTEM. MODELS ARE
IN GOOD AGREEMENT IN BRINGING 35-45KT WINDS BETWEEN 850-700MB OVER
THE REGION. FORECAST SOUNDINGS INDICATE THAT THE LOW LEVELS OF THE
ATMOSPHERE WILL BECOME ALMOST SUPER-ADIABATIC AND THOSE STRONGER
WINDS AROUND 700MB SHOULD BE ABLE TO MIX DOWN TO THE SURFACE,
RESULTING IN GUSTS UPWARDS OF 30 MPH FOR MOST LOCATIONS. SOUTHERN
MIDDLE TENNESSEE AND THE EASTERN HALF OF THE AREA WILL SEE SOME
STRONGER GUSTS UPWARDS OF 40MPH THIS AFTERNOON. THUS, WILL LEAVE THE
CURRENT WIND ADVISORY IN PLACE.

CAA ASSOCIATED WITH THE SYSTEM WILL KEEPS TEMPS WELL BELOW NORMAL FOR
THIS TIME OF YEAR WITH HIGHS TODAY IN THE LOW TO MID 60S AND NEAR 70
FOR FRIDAY. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE MID 40S TONIGHT
AND NEAR 50 DEGREES FOR FRIDAY NIGHT. LOOKING AT SOME OF THE UPSTREAM
OBSERVATIONS IT IS PROBABLY NOT OUT OF THE QUESTION FOR THE COLDEST
LOCATIONS IN THE CWA TO BRIEFLY DROP BELOW THE 40 DEGREE MARK
TONIGHT. THE ONLY THING THAT MAY PREVENT THAT FROM HAPPENING IS IF
WINDS WILL REMAIN ELEVATED TONIGHT.

THE SEMI-BLOCKING PATTERN ACROSS THE CONUS CONTINUES INTO THE WEEKEND
AS THE LOW FROM TODAY STALLS OUT OVER THE CAROLINAS FRI/SAT BEFORE
SHIFTING EAST INTO THE ATLANTIC. AS THIS BREAK DOWN OCCURS SAT/SUN
THE RIDGE AXIS TO OUR WEST WILL SHIFT OVER THE TN VALLEY AND RESULT
IN A WARMING TREND IN TEMPS THIS WEEKEND. SHOULD BE AN EXCELLENT
WEEKEND FOR OUTDOOR ACTIVITIES.

THE RIDGE/BLOCK PATTERN BREAKS DOWN AS WE HEAD INTO NEXT WEEK. THE
UPPER LEVEL LOW THAT HAS BEEN STUCK ACROSS THE SOUTHWESTERN US AS
PART OF THE BLOCK EJECTS EASTWARD INTO THE PLAINS SUNDAY INTO MONDAY.
WE QUICKLY RETURN TO SLY/SWLY FLOW WITH MOISTURE STREAMING BACK INTO
THE REGION. THERE SHOULD BE JUST ENOUGH OF THE DECAYING HIGH PRESSURE
SYSTEM LEFT OVER THE REGION ON MONDAY TO PREVENT ANY ACTIVITY THAT IS
GENERATED IN THE PLAINS FROM MAKING IT INTO THE AREA. THIS WILL NOT
BE THE CASE FOR TUESDAY, AS THE LOW LIFTS INTO THE MIDWEST SENDING A
SHORTWAVE THROUGH THE AREA AND BRINGING A RETURN OF SHOWERS AND
THUNDERSTORMS TO THE TENNESSEE VALLEY. MODELS ARE IN FAIR AGREEMENT
FOR THE GENERAL PATTERN FOR NEXT WEEK AND WHILE IT IS TOO FAR OUT TO
GET INTO ANY OF THE DETAILS IT LOOKS LIKE WE COULD SEE MULTIPLE
ROUNDS OF SHOWERS AND THUNDERSTORMS NEXT WEEK.

STUMPF

&&

.AVIATION...
FOR 12Z TAFS...
A STRONG LOW PRESSURE SYSTEM WILL MOVE JUST EAST OF THE AREA TODAY.
EXPECT GUSTY NORTH/NORTHWESTERLY WINDS AS A RESULT. WIND SPEEDS
INCREASE AFTER 14Z TO 10KTS WITH GUSTS 15-20KTS, BY 18Z SPEEDS WILL
RANGE FROM 15-20KTS WITH GUSTS UPWARDS OF 30KTS. THESE CONDITIONS ARE
FORECAST TO CONTINUE THROUGH 21-23Z THEN BEGIN TO TAPER OFF.

VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD WITH CIGS AOA 5000FT.
A FEW ISOLATED SHOWERS ARE POSSIBLE ACROSS FAR NE ALABAMA NEAR THE GA
STATE LINE.

STUMPF

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...WIND ADVISORY FROM 10 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR
     ALZ006-008>010.

TN...WIND ADVISORY FROM 10 AM THIS MORNING TO 8 PM CDT THIS EVENING FOR
     TNZ076-096-097.

&&

$$

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE
AT WEATHER.GOV/HUNTSVILLE.


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