FXUS64 KJAN 292111
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
311 PM CST SUN NOV 29 2009
.DISCUSSION...TONIGHT THROUGH MONDAY NIGHT...RAIN CHANCES WILL
INCREASE ACROSS THE ENTIRE FORECAST AREA FROM WEST TO EAST THROUGH
THE OVERNIGHT HOURS AS A COLD FRONT...WHICH CURRENTLY STRETCHES
SOUTHWEST FROM THE GREAT LAKES REGION THROUGH NORTHWEST ARKANSAS AND
SOUTHEAST OKLAHOMA...INTO NORTH CENTRAL AND CENTRAL TEXAS...MOVES
INTO WESTERN PORTIONS OF THE ARKLAMISS REGION LATE TONIGHT. AHEAD
OF THE FRONT...DECENT ISENTROPIC UPGLIDE WILL CONTINUE TO PRODUCE
PATCHES OF LIGHT...TO OCCASIONALLY MODERATE...RAIN ACROSS LOCATIONS
NORTH OF THE INTERSTATE 20 CORRIDOR...WHILE CLOUDS CONTINUE TO
INCREASE FROM WEST TO EAST ACROSS THE REGION. A COMBINATION OF ALL
THE ABOVE WILL ONCE AGAIN RESULT IN A MILD NIGHT AS OVERNIGHT LOWS
WILL RANGE FROM THE AROUND 50 ACROSS THE DELTA TO THE MID 50S ACROSS
SOUTHEAST MISSISSIPPI.
THE FRONT WILL BEGIN PUSHING SOUTHEAST INTO THE NORTHWEST HALF OF
THE FORECAST AREA AFTER MIDNIGHT TONIGHT...AND SHOULD EXIT SOUTHEAST
MISSISSIPPI DURING THE LATE MORNING/EARLY AFTERNOON HOURS MONDAY.
RAIN WILL GRADUALLY TAPPER OFF FROM NORTHWEST TO SOUTHEAST THROUGH
THE DAY...AND FINALLY COME TO AN END ACROSS SOUTHEAST MISSISSIPPI BY
MONDAY EVENING. BEHIND THE FRONT...SKIES WILL GRADUALLY CLEAR AS
COOLER DRIER AIR QUICKLY BEGINS FILTERING INTO THE CWA FROM THE
NORTHWEST...RESULTING IN A COOLER FEEL TO THE AIR OVER MUCH OF THE
FORECAST AREA MONDAY NIGHT.
THE PREVIOUS LONG TERM FORECAST DISCUSSION FOLLOWS. /19/
TUESDAY THROUGH SUNDAY...A WET PATTERN FOR THE EARLY PART OF THE
EXTENDED FOR THE ARKLAMISS. COLD FRONT MOVED THROUGH THE ARKLAMISS
ON MONDAY AND HIGH PRESSURE FILTERS IN FOR THE FIRST PART OF
TUESDAY. AS THIS IS OCCURRING...555DM MID LEVEL LOW SYSTEM IS
CHURNING ACROSS THE RIO GRANDE VALLEY. AHEAD OF THIS
SYSTEM...REFLECTION AT THE SFC IN THE FORM OF A 1007-1010MB LOW IS
LOCATED JUST OFF THE SOUTH CENTRAL TEXAS COAST ALONG PREVIOUS FRONTAL
BOUNDARY. AS THE MID LEVEL LOW BEGINS TO PROGRESS TO THE EAST...THE
SFC LOW MOVES EAST AS WELL. MODELS DIFFER IN THE TIMING AND PLACEMENT
OF THIS SFC LOW. BY 00Z WED. THE GFS HAS THE LOW JUST SOUTH OF NEW
ORLEANS WHEREAS THE ECMWF SHOWS IT STILL ALONG THE TEXAS COAST AND
SIMILAR SOLUTIONS TO THE ECMWF ARE ADVERTISED BY THE NAM AND SREF.
THIS SHOULD LEAVE MOST OF THE REGION FAIRLY DRY ON TUESDAY. THERE
COULD BE SOME LIGHT RAIN BEGINNING ON TUESDAY AFTERNOON DUE TO
ISENTROPIC LIFT ACROSS THE SOUTH AND HAVE INCLUDED SOME POPS IN
DURING THIS TIME PERIOD BUT LEFT NORTHERN SECTIONS DRY.
TIMING AND PLACEMENT DIFFERENCES BETWEEN MODELS LEAVE MUCH
UNCERTAINTY WITH MOST OF THE EXTENDED BUT IT LOOKS LIKE MOST OF THE
ARKLAMISS WILL SEE SOME RAIN WITH WED LOOKING TO BE THE WETTEST DAY.
MODELS INDICATE THAT THE HEAVIER/BULK OF THE RAIN WILL OCCUR
GENERALLY ALONG AND SOUTHEAST OF THE NATCHEZ TRACE WITH LESSER
AMOUNTS ACROSS THE MS DELTA. BY WED. MORNING...THE ECMWF AND OTHER
MODELS CONTINUE TO SHOW THE SFC LOW JUST TO OUR SOUTHWEST WITH THE
GFS FASTER WITH THE LOW ACROSS NW FL/S AL WITH THE MID LEVEL LOW
STILL ACROSS EAST CENTRAL TEXAS.
BY WED. NIGHT....THE BULK OF THE RAIN SHOULD MOVE OFF TO LOCATIONS
MUCH FARTHER EAST OF THE CWA AS THE MID LEVEL LOW ENTERS OUR REGION.
LINGERING LIGHT RAIN COULD AFFECT THE CWA THROUGH THURS. MORNING AND
HAVE TAPERED THIS FOR THE EAST/NORTHEAST WITH ONLY SLIGHT CHANCES IN
THE WEST PRIOR TO MIDNIGHT AND LEAVING ONLY SLIGHT CHANCES IN THE
EAST/NORTHEAST THROUGH DAYBREAK. CONDITIONS SHOULD REMAIN FAIRLY
DRY BEGINNING DURING THE DAY THURSDAY THROUGH MOST OF THE REST OF
THE PERIOD.
FOR THU-FRI. THE LARGER SCALE TROUGH SWINGS ON THROUGH AND COLD
HIGH PRESSURE RESUMES AT THE SURFACE. MODELS DIFFER ONCE AGAIN PAST
THIS POINT. THE GFS QUICKLY MOVES THE SFC HIGH OFF TO THE EAST WITH
SOUTHERLY FLOW RETURNING LATE FRIDAY INTO SATURDAY AND THE ECMWF
DOES NOT MOVE THE UPPER TROUGH THROUGH AS FAST AND LINGERS NORTHERLY
FLOW. WITH THE ECMWF THE RETURN FLOW AND EASTWARD PUSH OF THE HIGH
DOES NOT OCCUR UNTIL LATE SUNDAY. GFS WANTED TO BRING RAIN CHANCES
BACK WITH THE NEXT SYSTEM BY SATURDAY BUT HAVE OPTED TO KEEP THESE
OUT OF THE FORECAST UNTIL THERE IS A LITTLE BETTER AGREEMENT.
OVERALL...TRIED TO STAY CLOSE TO MAV/MEX NUMBERS GIVEN UNCERTAINTIES
IN THE EXTENDED. HOWEVER...DID INCREASE POPS FOR TUES-WED IN THE
SOUTH WHERE THE BETTER POTENTIAL FOR RAIN EXISTS AND CUT NORTHERN
POPS DOWN SOME. TRIED TO FOLLOW THE SLIGHTLY SLOWER TIMING OF THE
ECMWF/SREF WHICH WAS ALSO A LITTLE WETTER. TEMPS LOOKED GOOD AND
LITTLE ADJ NECESSARY. /28/
&&
.AVIATION...MOSTLY VFR CONDITIONS WILL PREVAIL ACROSS THE ARKLAMISS
THIS EVENING...BUT ISOLATED TO SCATTERED SHOWERS WILL CONTINUE
MAINLY FOR AREAS NORTH OF THE NATCHEZ TRACE. THESE SHOWERS MAY
OCCASIONALLY BRING MVFR CONDITIONS TO GWO/GLH AND TVR. A COLD FRONT
WILL BEGIN TO MOVE THROUGH THE AREA OVERNIGHT AND THE SHOWERS WILL
INCREASE IN COVERAGE. MVFR TO OCCASIONAL IFR CONDITIONS WILL BECOME
MORE WIDESPREAD AND AFFECT ALL SITES EXCEPT HBG OVERNIGHT INTO
TOMORROW MORNING AS THE FRONT DROPS SOUTH ACROSS THE AREA. VFR
CONDITIONS WILL RETURN FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA
MONDAY AFTERNOON INTO MONDAY EVENING AS HIGH PRESSURE BUILDS IN
BEHIND THE BOUNDARY. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 53 58 39 57 / 75 65 3 47
MERIDIAN 52 61 35 57 / 57 75 3 44
VICKSBURG 52 58 40 56 / 89 50 3 47
HATTIESBURG 55 65 40 57 / 24 82 11 64
NATCHEZ 53 57 41 55 / 76 64 8 65
GREENVILLE 50 53 38 56 / 100 30 2 23
GREENWOOD 50 54 37 59 / 100 41 2 23
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
19/15
