Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 251538 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1038 AM CDT MON MAY 25 2015

.DISCUSSION...IT HAS BEEN AN ACTIVE MORNING ACROSS EAST MS...WITH
MULTIPLE LOW TOPPED CELLS EXHIBITING ROTATION. A FEW OF THE STORMS
HAVE BECOME STRONG ENOUGH TO WARRANT A WARNING. THOUGH INSTABILITY
IS SOMEWHAT MODEST WITH MLCAPES MAINLY <1000 J/KG...LATEST SPC
MESOANALYSIS SHOWS AN AREA OF 200-300 M2/S2 EFFECTIVE SRH ACROSS
THIS REGION. THERE IS GOOD UPPER SUPPORT FOR CONTINUED CONVECTION
INTO THE EARLY AFTERNOON AS THE AREA RESIDES UNDER THE RIGHT REAR
QUADRANT OF AN UPPER JET MAX LIFTING ACROSS THE MID/UPPER MS VALLEY.
LATEST HRRR SUGGESTS CONVECTION PERSISTING OVER EAST MS INTO THE
EARLY AFTERNOON...WITH ADDITIONAL DEVELOPMENT FARTHER WEST THROUGH
THE DAY WITH DIURNAL INSTABILITY INCREASE.

GIVEN THE HISTORY OF STORMS THIS MORNING AND CURRENT ENVIRONMENT...
THE HWO/GRAPHICS WILL BE UPDATED TO HIGHLIGHT A LIMITED SEVERE
POTENTIAL ACROSS THE CWA TODAY. SOME MINOR UPDATES WILL ALSO BE MADE
TO WX WORDING TO ACCOUNT FOR CURRENT CONVECTIVE TRENDS. /DL/

&&

.AVIATION...NUMEROUS SHRA/TSRA WILL CONTINUE TO DEVELOP WITH DAYTIME
HEATING AND POSE HAZARDS TO GTR/MEI/HBG/JAN/HKS THIS MORNING INTO
THE AFTERNOON...THEN THE CONVECTIVE THREAT WILL SHIFT TO GLH/GWO
AREA TONIGHT. IN THE VERY MOIST AIRMASS...WIDESPREAD MVFR/OCNL IFR
CIGS WILL BE PREVALENT THROUGH THE AFTERNOON INTO TONIGHT. /EC/

&&

.PREV DISCUSSION... /ISSUED AT 411 AM CDT MON MAY 25 2015/
SHORT TERM...THROUGH TUESDAY NIGHT... EXPECTING A RATHER
ACTIVE PERIOD FOR THE SHORT TERM WITH THE POTENTIAL FOR SEVERE
STORMS AND SOME HEAVY RAINFALL.

BY 3 MID DAYTIME HEATING WILL KICK IN AS CONVECTION BUILDS FROM THE
WEST AND SOUTH TOWARD THE EVENING HOURS AHEAD OF THE NEXT SHORTWAVE.
ANOTHER SHORTWAVE WILL SWING ACROSS THE LOWER PLAINS/MS VALLEY
TONIGHT INTO EARLY TUESDAY. BEST POTENTIAL FOR SEVERE WEATHER
INCLUDING SOME POSSIBILITY FOR A TORNADO OR TWO WOULD BE ACROSS THE
DELTA...WHERE THE BEST OVERLAY OF STRONGER DEEP LAYER SHEAR AND
HELICITY IS PROGGED. 0-3 KM SHEAR WILL BE AROUND 40 KNOTS IN THAT
REGION. SO WILL KEEP THE CURRENT SEVERE LIMITED RISK FOR THE WEST
HALF FOR TONIGHT. HIRES MODELS SHOWS A PRETTY GOOD LINEAR MCS MOVING
INTO THE WEST DURING THE EVENING AND WEAKENING AS IT MOVES INTO THE
EAST DUE TO THE LACK OF FORCING. AS WE MOVE INTO TUESDAY WITH BETTER
DEEP SHEAR AND FORCING SPREADS EAST ACROSS THE CWA DURING THE DAY.
HIRES MODELS ALSO SHOWS A GOOD LINEAR MCS CROSSING THE REGION AT
THIS TIME...WHICH WILL HOLD TOGETHER BETTER. WILL KEEP THE PRIMARY
RISK OF DAMAGING WINDS...HAIL AND A TORNADO OR TWO CAN NOT BE RULED
OUT.

AS FAR AS THE HEAVY RAINFALL POTENTIAL IS CONCERN FOR THE SHORT
TERM. WITH GOOD MOISTURE TRANSPORT AND HIGH PWATS IT WILL BE A
CONCERN THROUGH THE PERIOD. RAINFALL AMOUNTS HAVE NOT BEEN THAT HIGH
WITH SOME LOCALIZED 4 INCHES ACROSS THE WEST MADISON...NORTH HINDS
AND LOWER AMOUNTS ELSEWHERE. SO WITH THIS IN MIND WILL HOLD OFF ON
ANY FLASH FLOOD WATCH AND LET THE DAY SHIFT REVISIT THE MATTER...ESP
WITH CONVECTION BEING A LITTLE LESS ACTIVE FOR MOST OF THE DAY. FOR
TUESDAY INTO TUESDAY NIGHT IF THINGS DO COME TOGETHER MAY HAVE TO
LOOK AT A FLOOD POTENTIAL FOR THAT PERIOD. WILL HOLD OFF ON ANY
GRAPHICS FOR THAT PERIOD FOR NOW./17/

LONG TERM...WEDNESDAY THROUGH MONDAY...BY WEDNESDAY MORNING
SLIGHTLY DRIER AIR ALOFT IS EXPECTED OVER THE NORTHWEST HALF OF THE
CWA WHERE PWS WILL BE BELOW AN INCH AND A HALF. PWS AROUND AN INCH
AND THREE QUARTERS WILL RESIDE OVER OUR SOUTHEAST. A SURFACE RIDGE
WILL REMAIN ALONG THE GULF COAST STATES MAINTAINING A WARM MOIST
FEED FROM THE GULF. A MORE SUBTLE SHORTWAVE IS EXPECTED TO MOVE OVER
OUR CWA DURING THE HEAT OF THE DAY AND LEAD TO A DECENT COVERAGE OF
CONVECTION. WIND FIELDS AND SHEAR LOOK TO REMAIN QUITE LIGHT THROUGH
THE DAY BUT MODELS SUGGEST VERTICAL TOTALS AROUND 29 AND DCAPE AROUND
1200J/KG OVER OUR DELTA REGION DURING THE AFTERNOON AND EARLY
EVENING WHERE A STRONG TO SEVERE STORM OR TWO WILL BE POSSIBLE. THIS
ACTIVITY WILL WEAKEN RAPIDLY WITH THE LOSS OF HEATING. THE SURFACE
RIDGE WILL REMAIN IN PLACE THURSDAY AND FRIDAY BUT RIDGING ALOFT
WILL STRENGTHEN FROM THE WESTERN GULF ACROSS THE SOUTHEAST STATES.
THIS WILL RESULT IN MORE ISOLATED TO SCATTERED DIURNAL COVERAGE OF
CONVECTION TO END THE WORK WEEK. BY SATURDAY ANOTHER SHORTWAVE
TROUGH IS EXPECTED TO BE OVER THE CENTRAL PLAINS. THE GFS IS A
LITTLE DEEPER WITH THE TROUGH AND STRONGER WITH THE ASSOCIATED
SURFACE LOW THAN THE ECMWF AND CMC...BUT CONSENSUS SUGGESTS POPS
WILL INCREASE GOING INTO SUNDAY AS THE SYSTEM DRAWS CLOSER. THE
TROUGH AXIS IS EXPECTED TO BE JUST WEST OF OUR CWA MONDAY EVENING.
NORMAL LOWS RUN IN THE MID 60S AND NORMAL HIGHS RUN 85 TO 87F. DUE
TO MOISTURE LEVELS REMAINING HIGH THROUGH THE PERIOD OVERNIGHT LOWS
WILL BE ABOVE NORMAL. AFTERNOON HIGHS WILL TOP OUT CLOSE TO NORMAL
THROUGH THE PERIOD. /22/

&&

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

$$

DL/EC/17/22



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