FXUS64 KJAN 092036
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
230 PM CST WED DEC 9 2009
.DISCUSSION...THE PRIMARY WEATHER CONCERN IS THE RAIN CHANCES FOR
FRIDAY INTO FRIDAY NIGHT AND IF THE MOISTURE DELAYS AFTER THE WARMER
AIR COMES IN FOR RAIN ONLY CHANCES. ALSO DETERMINING THE COOL TEMPS
AND POPS FOR THE PERIOD.
LATEST SATELLITE IMAGERY SHOWED A BROAD UPPER TROUGH OVER
THE CONUS. A STRONG UPPER JET WAS HELPING TO BRING A SURGE OF
CANADIAN AIR INTO THE REGION. IR/VIS IMAGERY SHOWS SOME PATCHY HIGH
CLOUDS MOVING OVER THE REGION. THE CENTER OF THE CANADIAN HIGH WAS
NOTED ACROSS THE PLAINS. A SECONDARY SURGE OF COOL CANADIAN AIR WAS
MAKING THROUGH THE ARKLAMISS THIS AFTERNOON. BREEZY CONDITIONS HAVE
WEAKENED SOME OVER THE REGION.
FOR TONIGHT AND THURSDAY SURFACE HIGH PRESSURE WILL MOVE OVER THE REGION
DURING THE PERIOD AND THE CENTER WILL BE JUST NORTHEAST OF THE REGION
BY LATE THURSDAY AFTERNOON. UNDER A BROAD UPPER RIDGE THE REGION
WILL BE UNDER WEST TO NORTHWEST FLOW OVER THE REGION. FOR TONIGHT
WILL BE A COOL NIGHT WITH LOWS IN THE MIDDLE 20S TO LOWER 30S.
MAV LOOKED A LITTLE WARM WENT CLOSER TO MOS GUIDANCE...DESPITE THE
WET GROUND. CLEAR SKIES AND LIGHT WINDS WITH COLD AIR ADVECTION SHOULD
HELP TEMPS FALL INTO MAINLY THE 20S. FOR THURSDAY IT WILL BE A COLD
DAY DESPITE FULL SUNSHINE. AS THE SURFACE HIGH MOVES OVER THE REGION
HIGHS WILL ONLY REACH THE MIDDLE 40S TO LOWER 50S. WENT CLOSE TO MAV
GUIDANCE.
FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE SURFACE HIGH WILL RETREAT
TO THE EASTERN US DURING THE PERIOD. THIS WILL ALLOW SOME RETURN OF
GULF MOISTURE TO THE REGION. WE WILL SEE A RETURN TO WARMER AND
WETTER WEATHER FOR THE PERIOD. A WEAK DISTURBANCE IN THE SOUTHWEST
FLOW ALOFT WILL HELP DEVELOP A SURFACE LOW OVER THE WESTERN GULF.
THIS WILL RESULT IN ISENTROPIC LIFT INCREASING OVER OUR REGION AND
RAIN DEVELOPMENT FROM THE SOUTH FRIDAY. IT WILL LIKELY TAKE MOST OF
THE DAY TO MOISTEN UP AND THE 12Z GFS IS STILL FASTER THAN THE
ECMWF/NAM AND SREF IN BRINGING LIGHT RAIN INTO OUR SOUTHERN ZONES
BUT NOT UNTIL THE AFTERNOON. LIGHT RAIN IS EXPECTED TO THE HIGHWAY
84 CORRIDOR BY EVENING. THIS RAIN AREA WILL SPREAD NORTH THROUGH
FRIDAY NIGHT. THE MODELS CONTINUE TO BE A LITTLE SLOWER IN MOVING
RAIN BACK INTO OUR AREA FOR FRIDAY SO WILL HAVE A CHANCE TO WARM UP
BEFORE SEEING ANY RAINFALL. MAV POPS LOOKED A LITTLE HIGH FOR FRIDAY
SO CUT POPS DOWN SOME FOR THE AFTERNOON. FOR FRIDAY NIGHT WENT CLOSE
TO MAV POPS. INSTABILITY WILL BE RATHER WEAK SO TOOK OUT THE ISOLATED
THUNDER CHANCES IN THE SOUTH. AS FAR AS TEMPS ARE CONCERN WENT CLOSE
TO MAV GUIDANCE FOR THURSDAY NIGHT WITH LOWS FROM THE MIDDLE 20S
NORTHEAST TO THE LOWER 30S SOUTHWEST AS WE GET BACK TO SOME RETURN
FLOW. IT WILL BE ANOTHER COLD DAY FOR FRIDAY WITH HIGHS FROM THE
MIDDLE TO UPPER 40S AS WE REMAIN UNDER THE INFLUENCE OF THE COOL CANADIAN
HIGH. FOR FRIDAY NIGHT MADE SOME ADJUSTMENTS TO MAV GUIDANCE. IT LOOKED
TOO COOL IN THE NORTH WITH THE LOWER 30S AND WITH CLOUDS AND A COOL
RAIN AROUND PUT TEMPS IN THE MIDDLE 30S NORTH TO LOWER 40S
SOUTH./17/
&&
.PREV DISCUSSION...LONG TERM...SATURDAY THROUGH WEDNESDAY...
DRIER WEATHER IS INDICATED FOR SUNDAY BUT ANOTHER WAVE IS EXPECTED
TO BRING RAIN ON MONDAY. A STRONGER SHORTWAVE IS EXPECTED TO MOVE
OVER THE SOUTHERN PLAINS MONDAY AND HELP DEVELOP A SFC LOW THAT IS
PROGGED TO MOVE ACROSS OUR CWA MONDAY NIGHT. RAIN CHANCES WILL
INCREASE LATE SUNDAY NIGHT AHEAD OF THE THIS SYSTEM AND LAST THROUGH
MONDAY. BOTH GFS AND ECMWF SHOW A STRONG COLD FRONT DROPPING INTO
OUR REGION TUESDAY MORNING WITH COLDER AND DRIER WEATHER SLATED FOR
WEDNESDAY. /22/
&&
.AVIATION...HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT AND ALLOW
SURFACE WINDS TO SUBSIDE. VFR CONDITIONS WILL PREVAIL THROUGH
THURSDAY NIGHT AS LITTLE MORE THAN CIRRUS CLOUDS MOVING ACROSS THE
AREA. FOG IS NOT EXPECTED IN THE DRY COLD AIRMASS. A DEVELOPING WARM
FRONT ALONG THE COAST AND SOUTHERLY FLOW ALOFT WILL BRING GRADUALLY
LOWER CEILINGS AND INCREASING CHANCES FOR LIGHT TO MODERATE RAIN AS
WE GO FROM FRIDAY INTO FRIDAY NIGHT. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 30 48 30 50 / 2 3 5 38
MERIDIAN 31 48 27 46 / 3 3 5 39
VICKSBURG 30 48 31 49 / 1 3 5 37
HATTIESBURG 33 50 31 47 / 4 3 8 56
NATCHEZ 29 49 33 48 / 3 3 9 56
GREENVILLE 28 45 29 46 / 0 3 5 21
GREENWOOD 27 45 28 47 / 0 3 5 23
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
