Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 260733
AFDHUN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
233 AM CDT SAT JUL 26 2014

.DISCUSSION...
WATER VAPOR AND MODEL ANALYSIS INDICATES A LARGE UPPER LEVEL
ANTICYCLONE OVER THE SOUTHERN CONUS. A POTENT UPPER LOW WAS
POSITIONED TO ITS NORTH OVER SASKATCHEWAN WITH A JET CORE IN BETWEEN
FROM THE NRN ROCKIES THRU THE GREAT LAKES AND OHIO VALLEY.

HOT WEATHER IS EXPECTED TODAY AND SUNDAY, WITH INCREASING MOISTURE
OWING TO HEAT INDEX VALUES OF 100-105F. WE SPLIT THE DIFFERENCE ON
THE MOS TEMPS (GFS HAS BEEN TYPICALLY TOO WARM), BUT THE ADVECTION
OF 850MB TEMPS IN THE L-M20S MAKE READINGS IN THE L-M90S SEEM VERY
PLAUSIBLE. FORECAST SOUNDINGS INDICATE A FORMIDABLE CAPPING INVERSION
TODAY, SO FEW CLOUDS ARE EXPECTED. DEW POINTS OF NEAR OR JUST ABOVE
70F WILL RETURN ON SUNDAY AS PERSISTENT S-SWLY FLOW OCCURS. THE CAP
MAY YET BE STRONG ENOUGH TO PREVENT DEEP CONVECTION, BUT WILL KEEP
ISOLATED T AS A POSSIBILITY DURING THE LATE AFTERNOON. IF THE CAP CAN
BREAK, INSTABILITY/CAPE AND A DRIER 8-5H LAYER WOULD SUPPORT
DOWNBURST ACTIVITY.

THE COLD FRONT ARRIVES SUNDAY EVENING IN SOUTHERN TN. ROBUST
CONVECTIVE ACTIVITY LOOKS TO BE ONGOING ALONG THE FRONT OVER EASTERN
TN WHICH SHOULD TEND TO BACK-BUILD WWD INTO THE FAVORABLE 25-35KT
LOW LEVEL INFLOW (9-8H LEVELS) AND THETA-E RIDGE POSN. THE CAPPING
INVERSION WILL LIKELY HOLD DEVELOPMENT BACK UNTIL THIS OCCURS. THE
CAP ALSO LENDS TO LOWER CONFIDENCE AS TO AREAL COVERAGE OF STORMS
SUNDAY NIGHT. MID LEVEL NWLY FLOW OF 30-35KT WILL INCREASE EFFECTIVE
BULK SHEAR VALUES, BUT NOT CERTAIN IF THIS WILL BE SUFFICIENT FOR A
SUPERCELL STORM MODE VS MULTI-CELL CLUSTERS AS UPPER LEVEL WINDS
REMAIN RELATIVELY WEAK. THE SPC OUTLOOK EMPHASIZING AREAS TO OUR NE
LOOKS GOOD, BUT A COUPLE OF SEVERE STORMS MAY OCCUR IN OUR AREA
SUNDAY NIGHT AS WELL.

AS HAS BEEN ADVERTISED, THE MEDIUM RANGE MODELS CONTINUE TO TAKE THE
UPPER LOW SE INTO THE A DEEPER TROF POSITION BY EARLY NEXT WEEK OVER
THE EASTERN CONUS WHILE THE RIDGE RETROGRADES WWD A ACROSS THE
ROCKIES/SWRN CONUS. THIS WILL BRING ANOTHER WELCOME PERIOD OF BELOW
AVERAGE TEMPS AND LOWER HUMIDITY THRU THE MIDDLE TO END OF NEXT WEEK.

AK

&&

.AVIATION...
/ISSUED 1159 PM CDT FRI JUL 25 2014/
FOR 06Z TAFS...
VFR CONDITIONS WILL PREVAIL THROUGH THIS TAF PERIOD. PATCHY SHALLOW
GROUND FOG COULD TEMPORARILY DROP VSBYS AROUND KMSL BTWN 08-12Z.

DJN.83

&&

.PRELIMINARY POINT TEMPS/POPS...
HUNTSVILLE    91  70  94  72 /   0   0  10  30
SHOALS        93  69  96  73 /   0   0  10  30
VINEMONT      89  68  93  73 /   0   0  10  30
FAYETTEVILLE  90  70  93  71 /   0   0  10  30
ALBERTVILLE   90  67  93  72 /   0   0  10  30
FORT PAYNE    90  67  93  72 /   0   0  10  30

&&

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

$$

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



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