000
FXUS64 KHUN 161939
AFDHUN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
239 PM CDT SUN JUN 16 2013

.DISCUSSION...
WATER VAPOR IMAGERY AND H5 RAP ANALYSIS INDICATED UPPER LEVEL RIDGING
BREAKING DOWN OVER THE SOUTHERN CONUS, WITH A FEW STORM SYSTEMS
TRAVERSING THE SOUTHERN CANADIAN PROVINCES THIS AFTN. AN UPPER LEVEL
LOW WAS COMING ASHORE IN THE PACNW, WITH AN UPPER LOW BECOMING AN
OPEN WAVE OVER SOUTH/CENTRAL CANADA, WITH THE LAST OF THE 3 SYSTEMS
QUICKLY PUSHING EASTWARD TOWARD NEWFOUNDLAND. SEVERAL DISTURBANCES
WERE NOTED WEST TO EAST ACROSS THE CENTRAL PORTIONS OF THE COUNTRY,
WITH THE ONE CROSSING THE MS RIVER RESPONSIBLE FOR THE SCT CONVECTION
ACROSS OUR LOCAL AREA THIS AFTN. ON THE SFC, A WEAK COLD FRONT WAS
DRAPED WESTWARD ACROSS THE GREAT LAKES REGION, EXTENDING SOUTHWESTWARD
BACK INTO THE CENTRAL PLAINS. SCATTERED SHOWERS/STORMS WERE NOTED ON
REGIONAL RADAR MOSAICS THIS AFTN.

FOR TONIGHT, EXPECT THE CONVECTIVE TREND TO CONTINUE AND OVERSPREAD
THE AREA FROM WEST TO EAST AS THE DISTURBANCE ALOFT PASSES OVERHEAD.
GIVEN THE INCREASING MOISTURE ACROSS THE AREA (WITH DEWPOINTS IN THE
UPPER 60S/LOWER 70S) AND SOUTHERLY FLOW IN PLACE, FELT CONFIDENT TO
INCREASE POPS FOR OVERNIGHT TO 50%. SHORT-TERM MODELS SUPPORT THIS
DECISION, WITH MOS GUIDANCE FOLLOWING SUIT AS WELL. THE ONLY FLY IN
THE OINTMENT FOR TONIGHT REVOLVES AROUND AN INTERESTING FEATURE OF
NOTE CURRENTLY DEVELOPING OVER THE ARKLAMISS AS OF THIS WRITING. A
LARGE CLUSTER OF TSTORMS IS UNDERWAY, MOVING OFF TO THE SOUTH/EAST.
THIS MAY CUTOFF MOISTURE/SOUTHERLY FLOW OVERNIGHT, WHICH WOULD IMPACT
THE COVERAGE OF SHRA/TSRA THROUGH 12Z MON. WILL MONITOR THIS TREND
AND THE EVENING SHIFT MAY NEED TO UPDATE THIS TONIGHT.

OTHERWISE, MODELS ARE IN DECENT AGREEMENT THAT SHOWERS/STORMS WILL
CONTINUE DEVELOPING AROUND THE AREA THROUGH EARLY WEDNESDAY AS THE
WEAK COLD FRONT TO THE NW MEANDERS SOUTHWARD, WASHING OUT SOMEWHERE
BETWEEN HERE AND MONTGOMERY, AL. THE ECMWF AND GFS DIFFER IN THEIR
OPINION OF EXACTLY WHERE THIS FRONT WILL END UP, WITH THE GFS FAR
MORE BULLISH WITH ITS SOUTHWARD EXTENT (ALONG THE COAST), WHEREAS THE
ECMWF IS MORE BELIEVABLE FOR THIS TIME OF YEAR (CLOSER TO OUR CWA)
GIVEN THE STRENGTH OF THE RIDGE THAT WILL BUILD IN BEHIND THIS FRONT.
WITH THE FRONT IN THE VICINITY AT THE SFC, AND SEVERAL DISTURBANCES
PASSING OVERHEAD ALOFT IN NW FLOW DURING THIS TIMEFRAME, HAVE
INCREASED POPS TO THE DEFINITE CATEGORY TOMORROW NIGHT INTO TUESDAY,
AS AN MCS DEVELOPS TO OUR NW AND ROLLS THROUGH BY 12Z TUESDAY. TEMPS
WILL HEAVILY DEPEND ON THE CONVECTION FROM TOMORROW THROUGH EARLY
WEDNESDAY, BUT FOR NOW, HAVE TRENDED TOWARD THE LOWER END OF MOS
GUIDANCE FOR HIGHS AND THE UPPER END OF MOS GUIDANCE FOR LOWS WITH
THE EXPECTATION OF CLOUDIER CONDITIONS WITH THE SHOWER/STORM COVERAGE
IN PLACE.

BEYOND WEDNESDAY, SHOWERS/STORMS WILL BE CONFINED SOUTH OF THE CWA AS
UPPER RIDGING BUILDS EASTWARD FROM THE SOUTHERN PLAINS. AT THE SAME
TIME, THE BERMUDA HIGH WILL PUMP MOISTURE INTO THE REGION FROM THE
SOUTHEAST, SPARKING AFTN/EVENING SHOWERS/STORMS BY THE WEEKEND.
WHETHER OR NOT ANY OF THIS ACTIVITY WILL BE ENHANCED OROGRAPHICALLY
IN OUR LOCAL AREA IS YET TO BE DETERMINED. WHILE WE`LL BE ON THE
EASTERN PERIPHERY OF THE UPPER RIDGE, OROGRAPHIC EFFECTS MAY BE
ENOUGH TO OVERCOME THE WEAKER RIDGING IN PLACE IN OUR EASTERN
COUNTIES. EITHER WAY, THE WEATHER PATTERN IS DEFINITELY TRYING TO
TRANSITION TO MORE OF A SUMMERTIME ONE, WITH CONVECTION MORE LINKED
TO PEAK HEATING, AND DISSIPATING SHORTLY AFTER SUNSET EACH DAY. AS
THE MID-SHIFT THIS MORNING NOTED, ASTRONOMICAL SUMMER OFFICIALLY
BEGINS AT 1204AM FRIDAY MORNING.

12

&&

.AVIATION...
/ISSUED 103 PM CDT SUN JUN 16 2013/
FOR 18Z TAFS...SCT SHRA/TSRA WILL CONTINUE TO DEVELOP IN THE VICINITY
OF THE TERMINALS THIS AFTN...AND WILL INCLUDE VCTS/CB AT BOTH
HSV/MSL. OUTSIDE OF PCPN...PREVAILING CONDS WILL BE VFR WITH CIGS
GENERALLY IN THE 7-18 KFT RANGE. HOWEVER...ANY SHRA/TSRA WILL BE
CAPABLE OF PRODUCING BRIEF PERIODS OF MVFR CIG/VSBY...GUSTY
WINDS...AND HEAVY DOWNPOURS. EXPECT THE THREAT FOR SCT SHRA/TSRA TO
PERSIST THRU THE NIGHT AS AN UPPER-LEVEL DISTURBANCE APPROACHES THE
REGION...BUT PREVAILING CIG/VSBY WILL REMAIN VFR UNTIL MID-MORNING
MONDAY WHEN SHRA/TSRA WILL BECOME MORE WIDESPREAD. SW SFC WINDS ARND
10 KNOTS CAN BE EXPECTED THIS AFTN AND MONDAY MORNING...WITH FLOW
BACKING TO SE AND DIMINISHING OVERNIGHT.

70/DD

&&

.PRELIMINARY POINT TEMPS/POPS...
HUNTSVILLE    71  88  71  86 /  50  70  80  60
SHOALS        71  87  71  86 /  50  70  80  60
VINEMONT      70  84  72  83 /  50  70  80  70
FAYETTEVILLE  71  86  70  85 /  50  70  80  60
ALBERTVILLE   69  83  70  81 /  50  70  80  70
FORT PAYNE    68  86  70  86 /  50  70  80  70

&&

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

$$

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