Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 230146 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
846 PM CDT TUE APR 22 2014

.UPDATE...EXPECT DRY WEATHER TONIGHT WITH OVERNIGHT LOWS IN THE LOW
TO MID 50S. PATCHY FOG WILL BE POSSIBLE LATE TONIGHT INTO TOMORROW
MORNING MAINLY ACROSS PORTIONS OF THE SOUTH. ONLY ADJUSTMENTS TO THE
CURRENT FORECAST WERE TO THE HOURLY TEMPS AND DEWPTS TO ACCOUNT FOR
THE LATEST TRENDS. /27/


&&

.AVIATION...VFR CONDITIONS WILL PREVAIL FOR MOST SITES THROUGH THE
PERIOD. THE EXCEPTION LOOKS TO BE KMEI AND KHBG WHERE IFR CEILINGS
AND VISIBILITIES WILL BE PROBABLE FROM 06-14Z WEDNESDAY MORNING.
VFR CONDITIONS WILL QUICKLY RETURN THEREAFTER. /26/


&&

.PREV DISCUSSION... /ISSUED 317 PM CDT TUE APR 22 2014/

DISCUSSION...
SHORT TERM (THROUGH THURSDAY NIGHT)...A COLD FRONT CONTINUES TO PUSH
SOUTHEASTWARD THROUGH THE CWA THIS AFTERNOON AND IS NOW SITUATED TO
THE SOUTHEAST OF THE NATCHEZ TRACE. SO FAR THERE HAS ONLY BEEN
ISOLATED SHOWER ACTIVITY EAST OF I-55. THERE COULD STILL BE
ADDITIONAL DEVELOPMENT OVER THE NEXT FEW HOURS...BUT COVERAGE IS
EXPECTED TO REMAIN ISOLATED...WITH LINGERING SHOWERS TAPERING OFF BY
AROUND SUNSET.

WITH THIS FRONT...THE DRIER AIR HAS BEEN LAGGING A BIT BEHIND THE
PRESSURE TROUGH...AS UPPER 50S DEWPOINTS HAVE JUST RECENTLY MADE IT
INTO THE NORTH WITH THE GRENADA AWOS CHECKING IN AT 59F. THIS WILL
CONTINUE TO BE THE CASE THROUGH THE NIGHT...WITH ADVECTION BEHIND THE
FRONT NOT PARTICULARLY STRONG. THERE MAY BE SUFFICIENT MOISTURE
LINGERING OVER PORTIONS OF SOUTH MISSISSIPPI FOR PATCHY FOG TO
DEVELOP TOWARD MORNING. WILL CONTINUE TO MENTION THIS POSSIBILITY
AROUND THE PINE BELT.

THE FRONT WILL STALL ALONG THE GULF COAST ON WEDNESDAY WITH THE
SOUTHERN PERIPHERY OF A SURFACE HIGH OVER THE GREAT LAKES BUILDING
DOWN INTO THE CWA...BRINGING AT LEAST ONE DRY DAY TO THE AREA. IN
SPITE OF THE FROPA...DAYTIME HIGHS WILL ACTUALLY BE SLIGHTLY ABOVE
NORMAL ON WEDNESDAY GIVEN THE NEGLIGENT COLD ADVECTION BEHIND THE
FRONT.

THE UPPER LEVEL PATTERN WILL REMAIN PROGRESSIVE HEADING INTO THE END
OF THE WEEK...AS A QUICK-MOVING UPPER TROUGH MOVES ACROSS THE PLAINS
STATES REPLACING THE UPPER RIDGE. SOUTHERLY LOW LEVEL FLOW WILL
RETURN BY THURSDAY MORNING...BRINGING A 1.3-1.4 INCH PWAT AIRMASS
BACK INTO THE DELTA BY THE AFTERNOON. CONTRARY TO THE GFS...THE
NAM/EURO/AND CANADIAN INDICATE A MORE ROBUST SHORTWAVE WITH THIS
SYSTEM...THUS WE OPTED TO GO ABOVE MAV POPS THURSDAY AFTERNOON/NIGHT.
THIS BRINGS RAIN CHANCES A BIT FARTHER SOUTH TO THE I-20 CORRIDOR.
MOST OF THE DAYTIME WOULD REMAIN DRY ON THURSDAY...WITH THUNDERSTORMS
DEVELOPING AHEAD OF THE ASSOCIATED SURFACE FRONT IN THE LATE
AFTERNOON...AND PUSHING EASTWARD THROUGH THE AREA. PROGGED 00Z
SBCAPES APPROACHING 2000 J/KG AND 0-6 KM BULK SHEAR VECTORS IN THE
40-50 KNOT RANGE OVER THE DELTA SUGGEST THE POTENTIAL FOR ORGANIZED
CONVECTION INCLUDING SOME SEVERE STORMS. THUS A LIMITED POTENTIAL FOR
SEVERE THUNDERSTORMS WILL BE INTRODUCED TO THE HWO/GRAPHICAST FOR
THIS TIME PERIOD FOR THE NORTHERN HALF OF THE AREA.

THE SURFACE FRONT WILL BECOME MORE DIFFUSE AND WILL ELONGATE FROM
WEST TO EAST DURING THE OVERNIGHT...LIKELY LIMITING THE SOUTHWARD
EXTENT OF PRECIPITATION THURSDAY NIGHT. /DL/

LONG TERM (FRIDAY THROUGH NEXT TUESDAY)...
/UPDATE/ THERE CONTINUES TO BE GROWING MODEL CONSENSUS IN A PERIOD
OF ACTIVE THUNDERSTORMS FROM SUNDAY PM THROUGH MONDAY AS A DEEP
NEGATIVELY-TILTED UPPER TROUGH BUILDS OVER THE MISSISSIPPI VALLEY.
CURRENT GUIDANCE INDICATES THE POTENTIAL FOR MULTIPLE ROUNDS OF
SEVERE WEATHER ACROSS THE REGION. GIVEN THE RUN-TO-RUN MODEL
CONSISTENCY SHOWING THIS SIGNAL...WE FELT IT WOULD BE PRUDENT TO
INTRODUCE MENTION OF SEVERE WEATHER POTENTIAL TO HWO/GRAPHICAST WITH
TODAYS FORECAST PACKAGE. IT GOES WITHOUT SAYING...THIS IS STILL IN
THE DAY 6/7 PERIOD AND THERE ARE STILL SEVERAL DETAILS WITH RESPECT
TO EXACT TIMING AND MODE THAT CANNOT BE RESOLVED AT THIS POINT IN
TIME. /DL/

THE FRONT WILL MOVE THROUGH TUESDAY WITH A LARGE UPPER LOW SPINNING
OVER THE OHIO VALLEY THROUGH THE END OF THE WEEK. THIS SHOULD BRING
IN MUCH COOLER AND DRIER AIR FOR THE BEGINNING OF MAY. /28/


&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       54  80  55  84 /   3   0   0  14
MERIDIAN      53  80  49  84 /   5   0   0  12
VICKSBURG     52  80  54  83 /   0   0   3  23
HATTIESBURG   58  83  56  85 /   8   0   5   7
NATCHEZ       56  80  58  83 /   0   0   5  10
GREENVILLE    53  78  55  82 /   0   0   0  39
GREENWOOD     51  77  53  83 /   0   0   0  29

&&

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

$$







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