Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 211434
AFDJAN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
934 AM CDT MON APR 21 2014

.UPDATE...

THE FORECAST IS GENERALLY ON TRACK THIS MORNING AND NO SIGNIFICANT
CHANGES WERE NECESSARY FOR THE NEAR TERM. HAVE REDUCED RAIN CHANCES
SLIGHLY FROM NE LA THROUGH CENTRAL MS WHERE THE AIRMASS NEEDS A BIT
MORE MOISTENING TO SUPPORT SHOWER ACTIVITY. FOG HAS DISSIPATED AND
HAVE REMOVED FROM MORNING FORECAST. /EC/

&&

.AVIATION...AS OF MID MORNING THE LAST OF THE LOW STRATUS WAS
LIFTING. OTHERWISE...ANTICIPATE INCREASING MID LEVEL CLOUD COVER
FROM THE WEST TODAY WITH ISOLATED TO SCATTERED RAIN SHOWERS MAINLY
CONFINED ALONG AND NORTHWEST OF THE NATCHEZ TRACE CORRIDOR. A STRAY
STORM IN THESE AREAS CANNOT BE RULED OUT. DURING THE DAY...EXPECT
SOUTH WINDS 7-12 KNOTS. RAIN SHOWERS AND EMBEDDED RUMBLES OF THUNDER
SHOULD BECOME A LITTLE MORE WIDESPREAD TONIGHT. /17/BB/

.PREV DISCUSSION... /ISSUED 510 AM CDT MON APR 21 2014/

SHORT TERM...TODAY THROUGH TUESDAY NIGHT...A MODEST AND PROGRESSIVE
UPPER LEVEL TROUGH WILL PASS OVER THE REGION TODAY THROUGH EARLY
AFTERNOON TOMORROW WITH EQUALLY MODEST LOBES OF ASSOCIATED ENERGY
HELPING INSTIGATE SOME PRECIPITATION FOR THE REGION. FOR THE BULK OF
TODAY THE FIRST LOBE OF ENERGY WILL INCREASE CLOUD COVER FROM THE
WEST AND PRODUCE ISOLATED TO SCATTERED SHOWERS...MAINLY ALONG AND
NORTHWEST OF THE NATCHEZ TRACE CORRIDOR. SOME MARGINAL INSTABILITY
WILL BE PRESENT (MAINLY ELEVATED IN NATURE) WHICH COULD GENERATE A
FEW RUMBLES OF THUNDER WITH NO SEVERE WEATHER ANTICIPATED. WORTH
MENTIONING THIS MORNING IS THE PROSPECT OF LOW CLOUDS AND SOME FOG
MAINLY ALONG AND SOUTH OF I-20 IN MISSISSIPPI AS MOSTLY CLEAR SKIES
ARE CATALYZED BY WEAK LOW LEVEL TRANSPORT OF GULF MOISTURE. AT THIS
TIME A DENSE FOG ADVISORY SHOULD NOT BE NECESSARY ALTHOUGH WE WILL
MONITOR. HIGHS TODAY WILL BE AROUND 80 DEGREES...WHICH IS SLIGHTLY
ABOVE AVERAGE.

BETTER INSTABILITY AND LIFT COMBINATIONS THIS AFTERNOON INTO THIS
EVENING WILL EXIST OVER EAST TX AND NEAR THE SABINE RIVER. THIS IS
WHERE LOOSELY ORGANIZED THUNDERSTORMS SHOULD DEVELOP AND PUSH
SOUTHEAST TOWARD WESTERN SECTIONS OF THE REGION IN THE EVENING. BUT
INSTABILITY SHOULD WANE CONSIDERABLY AS ACTIVITY MOVES INTO WESTERN
ZONES...ALTHOUGH A DECENT COVERAGE OF SHOWERS AND A FEW EMBEDDED
STORMS SHOULD AFFECT MY NORTHWESTERN ZONES TONIGHT. FURTHER EAST
SHOWERS OVERNIGHT WILL BE MUCH MORE HIT OR MISS ALTHOUGH A RUMBLE OF
THUNDER CANNOT BE RULED OUT IN MOST AREAS. LOWS WILL BE IN THE MILD
UPPER 50S TO LOWER 60S.

OF THE PREVIOUSLY-MENTIONED LOBES OF ENERGY...THE SECOND LOBE SHOULD
BE RESPONSIBLE FOR FIRING UP STORMS TO OUR WEST LATE TONIGHT AND
WILL WORK WITH AN INCOMING WEAK FRONT TO HELP TRIGGER SHOWERS AND A
FEW STORMS ACROSS THE HEART OF THE LOWER MS VALLEY ON TUESDAY. ALONG
WITH MOISTURE...INSTABILITY WILL AGAIN BE RATHER MARGINAL ACROSS OUR
REGION TUESDAY...WITH UNPHASED LIFT ALOFT AND IN THE LOWER LEVELS
NOT OPTIMUM FOR PRECIPITATION PRODUCTION. WE SHOULD STILL SEE RAIN
AT A GOOD MANY AREAS (PARTICULARLY EAST OF I-55) BUT ONLY TRACE
AMOUNTS COULD OCCUR IN QUITE A FEW SPOTS THAT DO SEE RAIN AND ANY
LOCALLY HEAVY DOWNPOURS SHOULD BE FEW AND FAR BETWEEN. THERE SHOULD
BE ENOUGH TEMPORARY CLOUD BREAKS TO GET TEMPS UP TO AROUND 80
DEGREES.

EXPECT PRECIP TO BE DIMINISHING QUICKLY OR EXITING TO THE EAST EARLY
TUESDAY EVENING WITH SKIES CLEARING FOR THE OVERNIGHT. COOLER AIR
(WELL DOWN INTO THE 50S) SHOULD PENETRATE BY DAWN WEDNESDAY AT LEAST
DOWN TO I-20...ALTHOUGH THERE IS SOME POTENTIAL FOR THE SURFACE
SOUTH OF I-20 TO REMAIN MILD AND MOIST WHICH MAY PROMOTE LOCALLY
DENSE FOG. THIS IS SOMETHING WE WILL HAVE TO WATCH. /BB/

LONG TERM...LONG TERM...WEDNESDAY THROUGH MONDAY. MODELS SEEM TO BE
IN GOOD AGREEMENT IN THE LONG TERM...SHOWING A SERIES OF FRONTS AND
LOW PRESSURE SYSTEMS PASSING THROUGH THE AREA FROM MID WEEK THROUGH
EARLY NEXT WEEK. LOOKS LIKE MORE RAIN IS HEADED THIS WAY. GUIDANCE
POPS AND TEMPS SEEMED OK. MADE SOME TWEAKS OVER THE WEEKEND...WHERE
WIDESPREAD CLOUDS AND SOME RAIN SHOULD KEEP TEMPS CLOSER TO 80.

BEHIND THE BOUNDARY TUESDAY...THE AREA WILL BE DRY FOR A DAY OR SO.
ANOTHER FRONT PASSES AROUND THURSDAY AFTERNOON...BUT NOW IT APPEARS
TO BE DRY. THERE COULD BE SOME ISOLATED ACTIVITY THURSDAY AS THE
BOUNDARY STALLS AND SEEMS TO GET DISPLACED BY ANOTHER BOUNDARY THAT
STALLS OVER THE AREA. INSTABILITY AND MOISTURE INCREASE ACROSS THE
AREA...SO LEFT SHOWERS AND THUNDERSTORMS IN THE FORECAST.
INSTABILITY SEEMED GOOD ENOUGH FOR THUNDER...BUT NOT QUITE HIGH
ENOUGH FOR SEVERE ON FRIDAY/FRIDAY NIGHT. HOWEVER...WITH A STALLED
BOUNDARY AND INCREASING MOISTURE...THE POTENTIAL FOR HEAVY RAIN WILL
INCREASE. THROUGH THE WEEKEND...THE BOUNDARY LINGERS OVER THE
AREA...KEEPING THE CHANCE RAIN CHANCES GOING. BY MONDAY...A MORE
SIGNIFICANT SYSTEMS APPROACHES THE AREA. OPTED TO LEAVE THE HWO
CLEAR AT THIS POINT...SINCE THE SYSTEM WAS JUST MOVING INTO THE
FORECAST. HOWEVER...THE SIG TOR PARAMETERS BLOW FROM THE SOUTHWEST
SUNDAY INTO MONDAY. THE GFS HAS DIFFERENT TIMING AND POSITION...BUT
THE EUROPEAN SHOW A 130KT JET STREAK MOVING ALONG I-20 ON THE BACK
SIDE OF A DECENT COLD FRONT LATE SUNDAY/EARLY MONDAY. THE MODELS
WANT TO BRING IN UPPER 60/LOWER 70 DEWPOINTS. WITH INCREASING
CAPE...NOT CRAZY VALUES AT THIS POINT...MOISTURE... A WELL
POSITIONED JET STREAK...A SURFACE BOUNDARY AND UPPER TROUGH...A
DECENT SEVERE WEATHER EVENT COULD DEVELOP EARLY NEXT.

DID NOT MAKE TOO MANY ADJUSTMENTS TO THE TEMPS. ALTHOUGH THE MODELS
WERE BRINGING IN HIGH DEWPOINTS ADJUSTED THEM DOWN FOR NOW. KEPT
VALUES IN THE LOWER TO MID 60S FOR THE MOST PART. WHILE THERE WAS
PLENTY OF SOUTHWEST FLOW...MODELS DIFFERED ON DEEP MOISTURE RETURN.
GENERALLY WENT WITH GUIDANCE TEMPS...DID LOWER VALUES A BIT ON
SATURDAY TO ACCOUNT FOR CLOUDY SKIES AND SCATTERED THUNDERSTORMS.
COULD BE WARMER IF CLOUDS ARE LATE TO DEVELOP.

&&

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

&&

$$







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