Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 241501 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1001 AM CDT SUN MAY 24 2015

.UPDATE...A STRATUS DECK COVERS MUCH OF THE CWA THIS MORNING. RADAR
WAS ALREADY SHOWING A FEW SHOWERS/STORMS DEVELOPING AND MOVING INTO
THE PINE BELT. MADE SOME MINOR ADJUSTMENTS TO THE FORECAST TO
INDICATE THE BEST CHANCE FOR ISOLATED/SCATTERED ACTIVITY MAINLY OVER
THE SOUTHERN HALF THIS MORNING. OTHERWISE THE GOING FORECAST APPEARS
TO BE ON TRACK AND NO BIG ADJUSTMENTS WILL BE MADE. /DL/

&&

.AVIATION...MOST SITES ARE MVFR/IFR THIS MORNING IN STRATUS
CLOUDS...BUT EXPECT VFR CONDITIONS TO PREVAIL AFTER 16-17Z AS THE
LOW CLOUDS LIFT. THUNDERSTORMS ACTIVITY WILL BE ON THE INCREASE THIS
AFTERNOON INTO THE EVENING HOURS AND THIS WILL BRING OCCASIONAL
MVFR/IFR CONDITIONS TO GWO/GLH/JAN/HKS. EXPECT A RETURN TO MVFR/IFR
CONDITIONS AT ALL SITES AFTER 05-06Z AS STRATUS CLOUDS ONCE AGAIN
DEVELOP OVER THE AREA./15/

&&

.DISCUSSION... /ISSUED AT 455 AM CDT SUN MAY 24 2015/
SHORT TERM...TODAY THROUGH MONDAY NIGHT...ACTIVE WEATHER PATTERN
SHAPING UP FOR THE NEXT FEW DAYS. MID/UPPER LEVEL RIDGE OVER THE MS
VALLEY WILL SHIFT EAST TODAY AS TROF OVER THE ROCKIES MOVES OUT IN
THE WESTERN HIGH PLAINS. THIS PUTS THE CWA SANDWICHED BETWEEN THE TWO
WITH INCREASED FLOW ALOFT. A COUPLE OF RATHER POTENT WAVES WILL
IMPACT THE AREA OVER THE NEXT FEW DAYS. THE FIRST WAVE WILL IMPACT
THE REGION LATE THIS AFTERNOON AND TONIGHT. CONVECTION IS ONGOING
WITH THE FIRST WAVE OVER TX WITH SEVERAL MCV/S NOTED ON AREA RADARS.
HIRES DATA INDICATES THAT BAND OF SHOWERS AND THUNDERSTORMS...
CURRENTLY DEVELOPING OVER SE TX WILL EXPAND NORTH AND EAST THIS
MORNING AND BEGIN IMPACTING WESTERN PORTIONS OF THE CWA BY MID
AFTERNOON. SCATTERED CONVECTION WILL ALREADY BE ONGOING...BUT THE
BEST CHANCE OF SEVERE WEATHER WILL BE ASSOCIATED WITH THE CONVECTIVE
BAND LATE IN THE DAY/EVENING.

SPEAKING OF SEVERE...WEAK LAPSE RATES (VERTICAL TOTALS IN THE MID
20S) WILL BE IN PLACE WITH A DEEP TROPICAL TYPE AIRMASS AS PW/S
APPROACH 2 INCHES. SHEAR...ON THE OTHER HAND...WILL BE MUCH BETTER
AS 25-35 KNOTS OF 0-1 KM BULK SHEAR AND 35-40 KNOTS OF 0-6KM BULK
SHEAR SETS UP OVER WESTERN SECTIONS LATE THIS AFTERNOON AND EVENING.
MAIN SEVERE THREATS THIS AFTERNOON/EVENING WILL BE DAMAGING WINDS.
UNIDIRECTIONAL WIND PROFILE/LOW HELICITIES SHOULD LIMIT THE TORNADO
POTENTIAL. WITH THE TROPICAL AIRMASS...LOCALLY HEAVY RAINS WILL ALSO
OCCUR. ONE HOUR FFG VALUES RUNNING 2.5-3 IN AT THE MOMENT...SO WE
SHOULD BE ABLE TO TAKE SOME RAIN BEFORE FLOODING WOULD BECOME A
PROBLEM.

NEXT WAVE LOOKS TO BEGIN IMPACTING THE AREA MONDAY NIGHT. ONCE
AGAIN...LAPSE RATES WILL BE WEAK AND SHEAR MORE PROLIFIC. THIS
TIME...HODOGRAPHS WILL HAVE SOMEWHAT BETTER CURVATURE AS 0-3 KM
HELICITIES APPROACH 250-300 M2/S2 AFTER MIDNIGHT OVER THE DELTA
REGION. ALTHOUGH WINDS/HEAVY RAIN WILL CONTINUE TO BE THE MAIN
WEATHER IMPACTS...WILL ADD SOME TORNADO WORDING TO THE HWO FOR THIS
TIME PERIOD AND AREA. MORE HEAVY RAINFALL WITH THIS WAVE MAY
POSE SOME PROBLEMS WITH RUNOFF BY MONDAY NIGHT. WILL HAVE TO WATCH
HOW THIS UNFOLDS AS AN FFA MAY BE NEEDED./26/

LONG TERM...TUESDAY THROUGH SATURDAY...ONCE AGAIN THE MODELS ARE
POINTING TO AN ACTIVE PATTERN MAINLY DURING THE FIRST PART OF THE
PERIOD. A NEGATIVELY TILTED SHORT WAVE WILL BE PIVOTING FROM THE
SOUTHERN PLAINS TO THE MIDDLE MISSISSIPPI VALLEY FOR TUESDAY-TUESDAY
NIGHT. THE MAIN UPPER JET ENERGY WILL BEGIN JUST WEST OF THE REGION
ON EARLY TUESDAY THEN WILL SHIFT OVER THE REGION THROUGH TUESDAY
NIGHT. SPC ALSO HAS A SLIGHT RISK OF SEVERE STORMS FOR TUESDAY INTO
TUESDAY NIGHT FOR MOST OF THE CWA. MODELS CONTINUE TO INDICATE SOME
DECENT INSTABILITY ALONG WITH 30-40 KNOTS OF 0-6 KM SHEAR TO WORK
WITH AS WELL AT THE 0-3 KM LEVEL. WE WILL GET THE BASE OF THE
PRIMARY JET ENERGY CROSSING THE REGION FOR TUESDAY INTO TUESDAY NIGHT
WITH 40-50 KNOTS AT 500 MB. MODELS SOUNDINGS STILL HAVE SOME
INTERESTING HODOGRAPHS FOR SOME ORGANIZED UPDRAFTS FOR SEVERE STORMS.
AT THIS TIME STILL THINK THAT THE PRIMARY CONCERN WILL BE DAMAGING
WINDS ALONG WITH SOME HAIL WITH SOME 6-7C LAPSE RATES. CIPS ANALOGUE
WAS ALSO HINTING AT SOME SEVERE CONCERNS. SO WILL ADD THIS TO THE HWO
FOR MOST OF THE REGION. OF SECOND CONCERN PWATS WILL BE FROM 1.7 TO
2.0 INCHES FOR TUESDAY WITH STRONG MOISTURE TRANSPORT. MODELS
CONTINUE TO SHOW THE POTENTIAL FOR SOME HEAVY RAINFALL FOR TUESDAY
WITH THE HEAVIEST AMOUNTS IN THE NORTHWEST. THE GFS WAS SHOWING 4-5
INCHES IN THE DELTA REGION BY TUESDAY EVENING. WPC HAS A EXCESSIVE
RAINFALL RISK FOR THE DELTA REGION THROUGH EARLY TUESDAY WITH A
GRAPHIC OF 3-4 INCHES IN THE WEST. CIPS ANALOGUE WAS ALSO PICKING UP
SOME SIGNALS FOR HEAVY RAIN POTENTIAL AS WELL. AS WE GO INTO THE REST
OF THE PERIOD WE WILL SEE SOME HEIGHT RISES AS WE GO TOWARD A MORE
DIURNAL DRIVEN REGIME FOR MAINLY AFTERNOON AND EARLY EVENING
CONVECTION. THE MEAN RIDGE WILL FLUCTUATE SOME DURING THE REST OF THE
PERIOD./17/

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&

$$

DL/15/26/17



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