FXUS64 KJAN 151008
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
408 AM CST TUE DEC 15 2009
.SHORT TERM...
TODAY THROUGH WEDNESDAY...COLD FRONT EXTENDS ACROSS THE CENTRAL
PORTIONS OF THE AREA THIS MORNING AND WILL WORKS ITS WAY TO THE COAST
BY LUNCHTIME. ABUNDANT MOISTURE STILL EXISTS ALONG AND BEHIND THE
BOUNDARY WITH PWATS ABOVE 1.6 INCHES FOR AREAS ALONG AND SOUTH OF
I-20. THIS COMBINED WITH A STRONG SHORT WAVE THAT WILL MOVE THROUGH
THE AREA THIS MORNING WILL KICK OFF ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS. THE SHOWERS ARE ALREADY DEVELOPING TO OUR WEST AND
WILL MOVE ACROSS THE CENTRAL AND SOUTHERN PORTIONS OF THE STATE
DURING THE MORNING HOURS BEFORE SHIFTING SOUTH EARLY THIS AFTERNOON.
DRIER AIR WILL BEGIN TO FILTER SOUTH THIS AFTERNOON WITH MOST OF THE
SHOWERS SHIFTING SOUTH OF THE AREA BY THIS EVENING. HEAVY RAINFALL IS
ONCE AGAIN LIKELY FOR AREAS SOUTH OF I-20 WITH ANOTHER 1 TO 3 INCHES
POSSIBLE OVER THE SAME AREAS THAT RECEIVED RAINFALL YESTERDAY...THUS
A FLASH FLOOD WATCH CONTINUES IN AFFECT FOR AREAS ALONG THE HIGHWAY
84 CORRIDOR.
HIGH PRESSURE RIDGING WILL BUILD IN AT THE SURFACE TONIGHT NOT ONLY
DRYING THINGS OUT...BUT WILL USHER IN MUCH COOLER AIR WITH LOWS IN
THE UPPER 20S TO LOW 30S. HIGH PRESSURE AND CLEAR SKIES WILL PREVAIL
ACROSS THE ARKLAMISS ON WEDNESDAY ALONG WITH COOL TEMPERATURES.
WENT WELL ABOVE GUIDANCE POPS FOR AREAS ALONG AND SOUTH OF I-20 ONCE
AGAIN TODAY AS ALL OF THE MODELS ALONG WITH RADAR TRENDS INDICATE
PRECIPITATION OVER THESE AREAS THIS MORNING. STUCK PRETTY CLOSE FOR
AFTERNOON HIGHS TODAY AND OVERNIGHT LOWS TONIGHT...BUT DID CUT
SLIGHTLY BELOW GUIDANCE HIGHS WEDNESDAY...ALTHOUGH GUIDANCE HAS COME
IN A LITTLE COOLER THAN PREVIOUS RUNS. AFTER LOOKING AT H925/H850
TEMPS AND GFS BUFR SOUNDINGS HAVE DECIDED TO CUT JUST A COUPLE OF
DEGREES BELOW OF GUIDANCE HIGHS./15/
.LONG TERM...
WEDNESDAY NIGHT THROUGH FRIDAY...
THE MODELS HAVE COME INTO BETTER AGREEMENT ON THE DEVELOPMENT OF A
NORTHWEST GULF LOW PRESSURE SYSTEM THIS FORECAST PERIOD. GIVEN THAT
BETTER LOW LEVEL MOISTURE TRANSPORT/CONVECTIVE POTENTIAL REMAIN
CONFINED TO COASTAL AREAS...THE WEATHER IMPACTS IN THE ARKLAMISS WILL
BE MINIMAL WITH LIGHT TO MODERATE RAIN (RAINFALL < .50 IN) FOR
LOCATIONS MAINLY SOUTH OF INTERSTATE 20. THIS QPF SCENARIO IS
DEPICTED BY THE 03Z SREF/06Z NAM/00Z GFS...WITH THE ECMWF SLIGHTLY
HEAVIER AND FARTHER NORTH. HAVE CONTINUED THE TREND OF CUTTING GFS
MOS HIGHS FOR THURSDAY GIVEN THE SHALLOW NATURE OF THE AIRMASS AND
EXPECTATION FOR ABUNDANT CLOUD COVER.
FRI NIGHT THROUGH MONDAY...
A MOSTLY DRY AND COLDER WEATHER REGIME IS FORECAST FOR THE WEEKEND
INTO EARLY CHRISTMAS WEEK AS STRONG UPPER LEVEL TROUGH DEVELOPS OVER
THE EASTERN CONUS. CONFIDENCE HAS INCREASED IN THE FORECAST FOR THE
LONGER RANGE PERIODS WITH THE 00Z GFS AND 00Z GFS ENSEMBLE MEAN NOW
IN GREAT AGREEMENT. AND THE 00Z ECMWF SHOWS ENOUGH AGREEMENT SO THAT
WE HAVE GENERALLY FOLLOWED THE GFS FOR FORECAST DETAILS.
AMPLIFICATION OF THE WESTERN RIDGE/EASTERN TROUGH PATTERN WILL
RESULT IN FAIRLY STRONG COLD ADVECTION SATURDAY AND SATURDAY NIGHT.
MODELS HAVE HINTED THAT A WEAK MID LEVEL TROUGH IN THE NORTHWEST
FLOW PATTERN COULD INDUCE VERY LIGHT PRECIPITATION OVER THE LOWER MS
VALLEY REGION AT SOME POINT FROM SATURDAY INTO SUNDAY. WITH THE
COLDER AIR MOVING IN AND LOW LEVEL INSTABILITY...BLUSTERY CONDITIONS
ALONG WITH A MIX OF SPRINKLES AND LIGHT SNOW SHOWERS/FLURRIES WILL
BE POSSIBLE...MOST LIKELY SATURDAY NIGHT. THIS WILL BE FOLLOWED BY
CHILLY AND DRY WEATHER FOR THE SUNDAY-MONDAY PERIOD WITH TEMPERATURES
10 DEGREES BELOW CLIMATIC AVERAGE. THE FORECASTED PATTERN SUGGESTS THERE
COULD BE A DAY OR NIGHT WHICH HAVE COLDER TEMPERATURES...BUT THE
FORECAST DETAILS ARE TOO DIFFICULT TO PIN DOWN AT THIS RANGE. /EC/
&&
.AVIATION...WIDESPREAD IFR/MVFR CONTINUE OVER MUCH OF THE AREA THIS
MORNING WITH ANOTHER ROUND OF SHOWERS MOVING IN THAT WILL AFFECT
JAN/MEI AND HBG. DRYER AIR WILL BEGIN FILTERING SOUTH BEHIND THE
COLD FRONT THIS AFTERNOON WITH MVFR CEILINGS IMPROVING TO VFR FOR
GWO/GLH AND GTR BY MID AFTERNOON AND FOR THE REMAINDER OF THE SITES
DURING THE LATE AFTERNOON/EARLY EVENING HOURS. THE WINDS WILL BE
GUSTY OUT OF THE NORTH AT GWO/GLH LATER THIS MORNING WITH GUSTS TO
NEAR 25 MPH POSSIBLE. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 52 36 57 36 / 40 0 0 0
MERIDIAN 56 33 56 35 / 54 0 0 0
VICKSBURG 51 36 54 36 / 35 0 0 0
HATTIESBURG 59 37 60 39 / 97 9 0 0
NATCHEZ 51 37 54 40 / 84 10 0 0
GREENVILLE 49 32 51 33 / 13 0 0 0
GREENWOOD 51 32 54 33 / 15 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR MSZ052-054>066-
072>074.
LAKE WIND ADVISORY FROM 7 AM THIS MORNING TO 4 PM CST THIS
AFTERNOON FOR MSZ026-030-031-043-049-052.
LA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR LAZ024-026.
LAKE WIND ADVISORY FROM 7 AM THIS MORNING TO 4 PM CST THIS
AFTERNOON FOR LAZ009.
AR...LAKE WIND ADVISORY FROM 7 AM THIS MORNING TO 4 PM CST THIS
AFTERNOON FOR ARZ075.
&&
$$
15/EC/
