FXUS64 KJAN 010340 AAB
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
940 PM CST MON NOV 30 2009
.UPDATE...SURFACE HIGH(1022MB) FANNING OUT NICELY FROM ERN OK ACROSS
THE MID SOUTH AND WILL MOVE THROUGH THE TN VALLEY EARLY TUESDAY.
PLENTY OF DRY AIR AVAILABLE AND CLOUDS HAVE THINNED OUT AND SHOULD
LAST FOR SEVERAL HOURS. HIGHER LEVEL MOISTURE ALREADY STREAMING OUR
WAY AS A SURFACE LOW(1012MB) SITTING IN THE WRN GULF AWAITS THE MID
LEVEL LOW CROSSING NRN MEXICO. LATEST 00Z NAM12 RUN HAS SHIFTED THE
SURFACE LOW TRACK CLOSE TO THE GFS ENSEMBLE MEAN FOR TUESDAY NIGHT
TAKING IT ROUGHLY ALONG I-59. THIS TRACK HOLDS MEASUREABLE RAINS BACK
UNTIL ABOUT MID AFTERNOON TUESDAY BEFORE RAPIDLY SURGING NWD ACROSS
THE SRN HALF OF OUR CWFA BY 6PM. WILL UPDATE THE HWOJAN TO INCLUDE
HEAVIER RAIN VOLUMES FOR SERN MS THROUGH MIDDAY WEDNESDAY
OTHERWISE...ONLY MINOR HOURLY GRID CHANGES TO CURRENT FORECAST. NO
TEXT FORECAST CHANGES ELSEWHERE AND DIGITAL UPDATES SHOULD BE
AVAILABLE. /40/
&&
PORTIONS OF PREV DISCUSSION... /ISSUED 400 PM CST MON NOV 30 2009/
DISCUSSION...HIGHER CLOUDS WILL BE INCREASING FURTHER ACROSS THE
WHOLE AREA TOMORROW AS THE MENTIONED SYSTEM GETS CLOSER. BY AFTERNOON
AN ASSOCIATED SURFACE LOW WILL BE STRENGTHENING AS IT HEADS TOWARD
THE LA COASTLINE. THE PRESENCE OF THIS LOW AND INSTABILITY SOUTH OF
THE COAST SHOULD PRODUCE A CLUSTER OF HEAVY RAIN AND THUNDERSTORMS
TOMORROW INTO TUESDAY NIGHT THAT MAINLY HUGS THE COAST SOUTH OF THE
ARKLAMISS. THERE SHOULD STILL BE SOME LIGHTER RAINS THAT EVENTUALLY
SPREAD NORTH THROUGH OUR AREA BY TOMORROW EVENING DUE TO STRONG
SYNOPTIC LIFTING MECHANISMS.
ELSEWHERE RAINFALL SHOULD NOT BE AT ALL HEAVY GIVEN STRONG MOISTURE
TRANSPORT BEING BLOCKED CLOSER TO THE COAST. RAIN TOTALS OF UP TO
ONE INCH ARE NOT OUT OF THE QUESTION IN SOME SPORADIC AREAS LATER
TOMORROW THROUGH WEDNESDAY NIGHT. TEMPERATURES WILL HAVE A TOUGH
TIME RISING MUCH DURING THE DAY OVER THE NEXT 48 HOURS AS THE SYSTEM
GIVES US CLOUDS AND RAIN WHILE A SURFACE LOW PASSING THROUGH THE
HEART OF THE ARKLAMISS KEEPS WARM ADVECTION AT THE GROUND AIMED
MAINLY TO OUR EAST. THE BIGGEST QUESTION WITH REGARD TO TEMPS WILL BE
HOW COLD IT GETS WEDNESDAY NIGHT SINCE THERE IS MUCH UNCERTAINTY
WHETHER OR NOT WINDS WILL DIE DOWN AND CLOUDS WILL CLEAR OUT BEFORE
THURSDAY MORNING. RIGHT NOW I OPTED TO GO THE WARMER ROUTE...WHILE
REMAINING NEAR THE COOLER GFS MODEL FOR TEMPS UP TILL THAT POINT. AT
THIS MUCH THERE IS VERY HIGH CONFIDENCE THAT ANY PRECIP SQUEEZED OUT
ON THE BACKSIDE OF THE DEPARTING SURFACE LOW LATER WEDNESDAY IN OUR
REGION WILL "NON-WINTRY". /BB/
PORTION OF PREVIOUS LONG TERM...FOR THU-FRI NIGHT...MODELS ARE
SHOWING A COLDER SOLUTION AND THINGS LOOK TO GET QUITE CHILLY FOR
THE END OF THE WEEK INTO THE WEEKEND. THIS WILL BE A RESULT OF THE
DEEP CYCLONE WHICH WILL CARVE OUT A SUBSTANTIAL TROUGH OVER THE MID
SECTION OF THE CONUS. TO PUT THIS TROUGH INTO PERSPECTIVE...MID
LEVEL HEIGHT ANOMALIES WILL RUN SOME 3 TO 4 STANDARD DEV BELOW CLIMO
VALUES. ADDITIONALLY...850MB TEMPS WILL ALSO BE SOME 3 TO 4 NEG
STANDARD DEV WITH ACTUAL 850MB TEMPS RANGING FROM (-2C TO -8C). ALL
THAT SHOULD RESULT IN TEMPS SOME 10-15 DEGREES BELOW NORMAL VALUES
FOR EARLY DEC...IF NOT A BIT COLDER. THIS IS ALL SUPPORTED BY THE
EURO AS WELL AS THE GFS ENSEMBLE. AS A RESULT...I HAVE GONE QUITE A
BIT COLDER THAN THE PREV FORECAST AND SOMEWHAT COLDER THAN THE
LATEST GFS GUID WHICH ITSELF WAS COLDER.
LASTLY...THE GFS WAS WANTING TO RETURN MOISTURE BACK LATE SAT NIGHT
INTO SUN. I AM NOT READY TO JUMP ON THAT AS THE EURO IS DRY AS IT
KEEPS THE SFC HIGH OVER THE REGION ANOTHER 24-36 HRS. THE GFS
ENSEMBLE IS MORE IN LINE WITH THE EURO AND AS A RESULT...I HAVE CUT
POPS AND LOWERED TEMPS FOR THAT TIME FRAME. /CME/
&&
.AVIATION...EVENING CONDITIONS GENERALLY VFR WITH SCATTERED MID-
HIGH LEVEL CLOUD LAYERS ABOVE 10K FEET. THICKER HIGH LEVEL CLOUD
SHIELD ADVANCING ACROSS LA AT 25KTS AND SHOULD COVER MY SWRN HALF OF
CWFA BY MIDNIGHT AND THE REST OF THE AREA BEFORE MORNING. NNE WINDS
HAVE DIMINISHED WITH SPEEDS BELOW 10 MPH AT MOST SITES. PATCHY FOG
WILL BE POSSIBLE TOWARD SUNRISE MAINLY NEAR LAKES AND RIVER IN LOW
LYING AREAS BUT VSBYS SHOULD REMAIN ABOVE 4SM AT MOST LOCATIONS.
HIGHER CLOUDS WILL THICKENING/LOWERING OVER THE FORECAST AREA TUESDAY
MORNING WITH CLOUD LAYERS LOWERING TO 3-5K FEET WITH INCREASING
CHANCES OF RAIN TUESDAY AFTERNOON 18-22Z. MVFR CONDITIONS WILL RESUME
TUESDAY EVENING OVER MOST TAF SITES. /40/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 39 54 47 52 / 1 29 80 60
MERIDIAN 37 54 48 58 / 1 40 83 70
VICKSBURG 39 53 47 50 / 1 25 80 63
HATTIESBURG 42 53 52 57 / 4 89 99 52
NATCHEZ 42 53 48 51 / 4 44 87 50
GREENVILLE 35 51 45 49 / 0 12 80 82
GREENWOOD 36 55 45 50 / 0 15 71 81
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
