Area Forecast Discussion
000
FXUS64 KJAN 131333 RRA
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
355 AM CST MON NOV 13 2006
.SHORT TERM...TODAY THROUGH TUESDAY...ANOTHER CHILLY MORNING ON TAP
FOR MUCH OF THE CWA. A DRY AIRMASS...CLEAR SKIES AND LIGHT WINDS
HAVE ALLOWED TEMPERATURES TO DROP INTO THE LOWER 30S IN EAST
MISSISSIPPI THIS MORNING WITH UPPER 30S AT MOST OTHER LOCATIONS.
SATELLITE IMAGERY SHOWS HIGH CLOUDS MOVING INTO OUR SOUTHEAST
ARKANSAS COUNTIES AND LOUISIANA PARISHES. THESE CLOUDS WERE AHEAD OF
AN APPROACHING SHORTWAVE TROUGH THAT WILL MOVE ACROSS OUR REGION
TODAY. REGIONAL RADARS SHOWED A BAND OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS JUST AHEAD OF THE TROUGH AXIS OVER CENTRAL ARKANSAS
AND EXTENDING BACK ACROSS NORTHWEST LOUISIANA. AS THE SHORTWAVE
TROUGH MOVES EAST TODAY IT WILL WEAKEN AND THE ASSOCIATED PCPN WILL
MOVE INTO OUR DRIER AIRMASS. VERY LITTLE MEASURABLE PRECIPITATION IS
EXPECTED IN OUR CWA TODAY...AND THE LITTLE THAT FALLS WILL BE MAINLY
OVER THE NORTHERN COUNTIES. WL CUT POPS SLIGHTLY AND ONLY MENTION
SPRINKLES BY AFTERNOON. CLOUDS AND SPRINKLES IN THE NORTH WILL HELP
HOLD TEMPERATURES DOWN IN THERE TODAY. HIGHS THERE WILL ONLY TOP OUT
IN THE LOWER 60S. CLOUDS WILL DECREASE THIS EVENING AS THE SHORTWAVE
SHIFTS EAST OF OUR REGION...BUT INCREASE TOWARDS MORNING AHEAD OF
ANOTHER WEAKER SHORTWAVE THAT WILL MOVE OVER OUR CWA TUESDAY
MORNING. MINIMUM TEMPERATURES WILL BE SEVERAL DEGREES WARMER TUESDAY
MORNING THAN THIS MORNING...BUT OUR NORTHEAST COUNTIES WILL DIP INTO
THE UPPER 30S AGAIN. ALTHOUGH NO PRECIPITATION IN EXPECTED IN OUR
CWA TUESDAY MORNING ASSOCIATED WITH THE WEAK SHORTWAVE...WAA WILL
BEGIN IN THE WEST AHEAD OF THE DEVELOPING LOW PRESSURE SYSTEM OVER
THE SOUTHERN PLAINS. A FEW SHOWERS WILL BE POSSIBLE BY LATE
AFTERNOON IN OUR SOUTHWEST COUNTIES AND LOUISIANA PARISHES. /22/
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...A 140KT JET WILL
CONTINUE DOWN THE BACKSIDE OF THE UPPER LEVEL TROUGH TUESDAY NIGHT
DIGGING OUT A VERY DEEP TROUGH THAT WILL POSSIBLY BRING SEVERE
WEATHER TO THE ARKLAMISS INTO WEDNESDAY MORNING. ALONG WITH THE
STRONG JET A DEEPENING 500MB LOW WILL MOVE FROM OKLAHOMA TO
TENNESSEE FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT. A SURFACE LOW
WILL MOVE OUT OF THE ROCKIES AND RAPIDLY DEEPEN AS IT MOVES ACROSS
ARKANSAS INTO TENNESSEE WEDNESDAY MORNING. THE GFS AND THE NAM HAVE
COME IN LINE WITH THE TIMING OF THIS SYSTEM AS IT MOVES ACROSS THE
ARKLAMISS. THE BIG QUESTION AS MENTIONED IN PREVIOUS AFD`S IS THE
INSTABILITY. THE LATEST GFS AND NAM ARE ONLY BRINGING UP LOW TO MID
60 DEWPOINTS ACROSS THE AREA EARLY WEDNESDAY AHEAD OF THE SYSTEM AND
THUS ML CAPES ARE ONLY IN THE 500-700 J/KG RANGE...THE NAM IS EVEN
LOWER. THE GFS DOES INDICATE DECENT 700-500MB LAPS RATES EARLY
WEDNESDAY OF NEAR 6.5 C/KM. THERE WONT BE ANY LACK OF SHEAR WITH
THIS EVENT WITH 0-3 HELICITIES OF OVER 400 M^2/S^2 AND A BULK SHEAR
OF 50KTS PLUS.
WITH ALL OF THIS IN MIND...THE AMOUNT OF FORCING ASSOCIATED WITH
THIS SYSTEM WILL BE IMPRESSIVE AND EVEN WITH THE LIMITED INSTABILITY
THERE SHOULD BE SEVERE STORMS OVER MOST OF THE AREA. THE MAIN RISK
WILL BE HAIL AND WINDS...BUT THE GREATEST RISK FOR TORNADOS
CURRENTLY LOOKS TO BE SOUTH OF THE I-20 CORRIDOR WERE THE HIGHEST
DEWPOINT RECOVERY WILL BE WITH DEWPOINTS NEAR 65.
THE FRONT WILL MOVE THROUGH EARLY WEDNESDAY AND THE WINDS BEHIND THE
BOUNDARY WILL BE QUITE GUSTY WITH 40KTS JUST OFF OF THE SURFACE AND
STRONG COLD AIR ADVECTION. WILL HAVE TO CONTINUE TO MONITOR FOR
POSSIBLE WIND ADVISORY. THERE WILL ALSO CONTINUE TO BE SOME SHOWERS
AROUND WEDNESDAY NIGHT ASSOCIATED WITH THE UPPER LOW AND SOME WRAP
AROUND MOISTURE.
AFTER THIS SYSTEM MOVES THROUGH THE WEATHER WILL BECOME BENIGN WITH
HIGH PRESSURE PREVAILING OVER THE AREA WITH ONLY A WEAK FRONTAL
SYSTEM MOVING THROUGH SATURDAY. STUCK PRETTY CLOSE TO GUIDANCE FOR
THE MOST PART EXCEPT FOR THE TUESDAY NIGHT PERIOD. THE MODELS HAVE
SEEM TO COME TOGETHER ON THE TIMING OF THE SYSTEM SO ITS A PRETTY
GOOD BET THAT EVERYONE WILL MEASURE DURING THIS PERIOD. WITH THIS IN
MIND HAVE BUMPED UP POPS TO 100 FOR MOST OF THE AREA FOR THIS PERIOD.
ALSO CUT GUIDANCE LOWS FRIDAY MORNING A COUPLE OF DEGREES MAINLY IN
THE CENTRAL AND EAST AS H850/H925 TEMPERATURES SUPPORT LOWS IN THE
LOW 30S. /15/
&&
.AVIATION...MVFR CONDITIONS ARE EXPECTED THIS MORNING THROUGH 13Z
AND MOSTLY EAST OF THE MISSISSIPPI RIVER. A LINE OF LIGHT SHOWERS
WILL MOVE ACROSS THE AREA TODAY AND MAY RESULT IN A BRIEF PERIOD OF
CEILINGS AROUND 3000FT. HOWEVER...MOST OF THE AREA WILL REMAIN UNDER
VFR CONDITIONS THROUGH 06Z TUESDAY. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 65 41 68 54 / 14 5 14 100
MERIDIAN 66 37 68 56 / 13 4 9 88
VICKSBURG 64 42 67 53 / 18 5 13 100
HATTIESBURG 69 40 68 58 / 7 5 17 83
NATCHEZ 64 44 68 54 / 20 4 21 100
GREENVILLE 60 43 66 52 / 24 5 10 100
GREENWOOD 60 41 67 53 / 24 5 7 100
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
SHORT TERM/AVIATION: 22
LONG TERM: 15