FXUS64 KMEG 231745
AFDMEG
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1145 AM CST WED DEC 23 2009
.UPDATE...
UPDATED FOR 18Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 1014 AM CST WED DEC 23 2009/
DISCUSSION...
EXPECT STEADY RAIN TO CONTINUE THROUGH THE DAY WITH THE LEADING
EDGE ADVANCING EASTWARD. CANNOT RULE OUT EMBEDDED THUNDER IN THE
WEST FROM ELEVATED INSTABILITY. WINDS WILL INCREASE THROUGHOUT THE
CWA AS THE SURFACE LOW OVER TEXAS MOVES EASTWARD AND STRENGTHENS.
UPDATED THE FORECAST THIS MORNING TO PROVIDE MINOR ADJUSTMENTS TO
THE PRECIPITATION CHANCES. WILL CONTINUE TO MONITOR THE FORECAST.
SWC
PREV DISCUSSION... /ISSUED 253 AM CST WED DEC 23 2009/
DISCUSSION...
THE CHALLENGE WILL BE RAIN...WIND AND POSSIBLE STRONG
THUNDERSTORMS IN NORTH CENTRAL MISSISSIPPI IN THE FIRST 36 HOURS
OF THE FORECAST PERIOD.
TODAY...RAIN SHOWERS WILL SPREAD ACROSS THE MID SOUTH TODAY AS A
POWERFUL H5 UPPER LEVEL TROUGH MOVES INTO THE SOUTHERN ROCKIES.
TONIGHT AND CHRISTMAS EVE...THIS H5 TROUGH CAUSES RAPID AND
DEEPENING SURFACE CYCLOGENESIS IN EASTERN TX. SURFACE GRADIENTS
WILL RAPIDLY TIGHTEN WITH ADVISORY CRITERIA MAGNITUDE SPEEDS.
EXPECT THE DAY SHIFT TO ISSUE A WIND ADVISORY FOR THIS TIME FRAME.
HEAVY RAIN IN MORE INTENSE SHOWERS AND ISOLATED THUNDERSTORMS IS
POSSIBLE AHEAD OF A SURFACE COLD FRONT. DO NOT EXPECT FLOODING
ISSUES SINCE THE COLD FRONT WILL BE MOVING EAST AT 50-60 MPH.
WILL HAVE TO MONITOR THE POTENTIAL FOR STRONG THUNDERSTORMS ON
CHRISTMAS EVE IN NORTH CENTRAL MS. RECENT MODEL RUNS HAVE BROUGHT
THE WARM SECTOR FARTHER NORTH WITH POSITIVE MUCAPE VALUES AS FAR
NORTH AS CENTRAL MS. EXPECT A SQUALL LINE WITH DAMAGING WINDS TO
CLIP THE SOUTHERN TIER OF COUNTIES IN THIS SERVICE AREA.
THURSDAY NIGHT THROUGH SUNDAY...MUCH COLDER AIR USHERS IN BEHIND
THE COLD FRONT THURSDAY NIGHT AND LINGERS INTO THE WEEKEND. THE H5
AND SURFACE LOWS BECOME STACKED OVER IOWA ON CHRISTMAS DAY AND
ONLY BEGIN TO PROGESS EAST ON SUNDAY. ALTHOUGH THE BEST MOISTURE
AND LIFT REMAIN CLOSE TO THE STACKED LOWS...EXPECT CLOUDS TO
LINGER ACROSS THE NORTHERN THIRD OF THE MID SOUTH AND A CHANCE OF
SNOW SHOWERS ON CHRISTMAS DAY IN THAT AREA.
MONDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE MOVES INTO THE
REGION FOR DRY WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES. THE
NEXT STORM SYSTEM FORECAST BY THE 00Z GFS/ECMWF IS JUST BEYOND THE
FORECAST PACKAGE.
OKULSKI
&&
.AVIATION...
18Z TAF CYCLE.
THREAT OF LOW LEVEL WIND SHEAR. HAVE NOT CHANGED MUCH FROM
PREVIOUS 12Z CYCLE...EXCEPT BELIEVE THUNDERSTORM PROBABILITY IS
GREATER MAINLY AFTER 08Z...MORE SPECIFICALLY FROM 14Z-18Z
THURSDAY AS THE COLD FRONT AND STRONG UPPER FORCING CLOSES IN ON
OUR AREA.
BELLES
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 58 52 57 36 / 100 80 100 40
MKL 57 50 58 36 / 80 70 100 50
JBR 56 50 53 33 / 100 90 100 30
TUP 59 51 62 38 / 70 60 100 50
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
