FXUS64 KJAN 301043
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
443 AM CST MON NOV 30 2009
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...IT IS A LITTLE BUSY IN
THE SHORT TERM WITH ONE SYSTEM MOVING THROUGH THIS MORNING/EARLY
AFTERNOON FOLLOWED BY ANOTHER AT THE END OF THE PERIOD. RESIDENTS
COULD SEE MORE RAIN THIS WEEK THAN THEY HAVE DURING THE WHOLE MONTH
OF NOVEMBER.
AS OF ABOUT 10Z...SURFACE FRONT IS LOCATED GENERALLY FROM SOUTH OF
MONROE LOUISIANA...TO NORTH OF JACKSON...TO SOUTH OF TUPELO. LARGE
AREA OF LIGHT TO MODERATE RAIN BEHIND THE FRONT LOCATED JUST ALONG
OR SLIGHTLY TO THE NORTH OF THE NATCHEZ TRACE. THERE HAVE BEEN SOME
EMBEDDED THUNDERSTORMS WITHIN SOME OF THE HEAVIER CONVECTIVE AREAS.
FOR TODAY...FRONT WILL CONTINUE TO TREK THROUGH THE CWA THROUGH THE
REMAINDER OF THE MORNING. ALL MODELS AND LOCAL WRF RUNS ARE IN VERY
GOOD AGREEMENT THAT ALL OR MOST OF THE RAIN SHOULD BE THROUGH THE
CWA BY AROUND 18Z. BEHIND THE FRONT...CONDITIONS COULD BE RAW WITH
TEMPS COOLING INTO THE UPPER 40S TO LOWER 50S WITH GUSTY NORTHERLY
WINDS. AT THIS TIME...LAKE WIND ADV CRITERIA DOES NOT LOOK TO BE MET
THOUGH IF VENTURING OUT ONTO LAKES...CONDITIONS COULD BE GUSTY AT
TIMES. CLOUDS WILL LINGER FOR A LITTLE BIT BEFORE GRADUALLY CLEARING
OUT A BIT LATE THIS EVENING INTO TONIGHT.
SHORTWAVE RIDGING AND HIGH PRESSURE AT THE SURFACE WILL TAKE PLACE
TONIGHT AND ALLOW FOR A QUIET NIGHT AND MUCH OF THE DAY ON TUESDAY.
HOWEVER...THE NEXT SYSTEM MOVES IN LATE TUESDAY. ON TUESDAY...MID
LEVEL LOW OVER THE RIO GRANDE VALLEY AREA WILL MAKE ITS WAY EAST
WHILE CYCLOGENESIS AT THE SFC WILL FORM A LOW ALONG THE PREVIOUS
FRONTAL BOUNDARY JUST SOUTH OF THE CENTRAL TEXAS COAST.
MODELS ARE NOT IN MUCH BETTER AGREEMENT THAN LAST NIGHT. THE
ECMWF/SREF/NAM ALL CONTINUE TO INDICATE THE SFC LOW TRACK ACROSS THE
CWA WHILE THE GFS CONTINUES TO BE THE OUTLIER AND BRING THE LOW MUCH
FURTHER TO THE SOUTH AND EAST. HOWEVER...ALL MODELS HAVE SPED THE
TIMING UP FROM WEDNESDAY TO THIS EVENT OCCURING MORE ON TUESDAY
NIGHT. I WILL CONTINUE TO FOLLOW A LITTLE CLOSER TO THE
ECMWF/SREF/NAM. THIS WOULD BEGIN TO INTRODUCE RAIN BACK INTO THE
SOUTHWEST CWA BY TUESDAY LATE AFTERNOON WITH SLIGHT
CHANCES...GRADUALLY BECOMING MORE LIKELY THE LATER INTO THE
AFTERNOON AND EVENING WE GO. THE MAIN TIMEFRAME FOR RAIN WILL
DEFINITELY BE OVERNIGHT TUESDAY NIGHT/WED. MORNING. WITH THIS
TRACK...THERE IS THE POSSIBILITY FOR SOME ISOLATED THUNDER IN SOME
OF THE HEAVIER CONVECTIVE BANDS SO HAVE MAINTED THE THUNDER WORDING
MAINLY FOR SOUTHEAST MS FROM THE NATCHEZ TRACE TO I-59 CORRIDOR
AREA. THIS WILL BE THE SAME REGION THAT SHOULD RECEIVE THE HEAVIEST
RAIN AND IS WHERE THE BETTER MOISTURE TRANSPORT/CONVERGENCE OCCURS. MODELS
INDICATE THAT ANYWHERE FROM 1 TO 3 INCHES COULD OCCUR IN THIS
REGION. WILL CONTINUE TO MENTION HEAVY RAIN THREAT IN THE HWO. IN
ADDITION...SPC HAS GONE AHEAD AND PUT PORTIONS OF MS SOUTH OF OUR
CWA UNDER A 5% SVR DAY 2 SVR OUTLOOK. HOWEVER...DEPENDING ON THE
TRACK OF THE LOW...THIS COULD BE EXPANDED FURTHER INTO OUR CWA OR
PUSHED FURTHER SOUTH OF OUR CWA. GIVEN FORCING/PROXIMITY TO THE
LOW...BEING IN THE WARM SECTOR OF THE LOW(WITH THE POSSIBILITY FOR
SOME HIGHER DEWPOINTS ACROSS THE SOUTHEAST)AND HIGH SHEAR
VALUES(DESPITE LIMITED INSTABILITY)...THERE COULD BE A SMALL
TORNADO THREAT WITH THIS AND IS DEFINITELY SOMETHING TO KEEP IN MIND
WITH FUTURE FORECASTS AS THE LOW TRACK BECOMES CLEARER.
OVERALL....MADE SOME ADJ TO THE FORECAST. RAISED POPS FOR TODAY FOR
LOCATIONS SOUTH AND EAST AND MOST LIKELY TO GET RAIN. DID CUT SOME
ACROSS THE DELTA WHERE RAIN SHOULD END QUICKER. ALSO FOR TUES...I
CUT POPS NORTH AS DRIER AIR SHOULD PRECLUDE ANY APPRECIABLE RAIN.
LOCATIONS ALONG I-20 WERE CUT SOME AND LOCATIONS TO THE SOUTH WILL
HAVE THE BEST CHANCE FOR ANY RAIN AND WAS LEFT IN TACT. TUES NIGHT
POPS WERE LEFT AS THEY WERE ALREADY HIGH TO BEGIN WITH. DID BUMP UP
POPS IN THE SOUTH A LITTLE AS TRACK IS STILL A LITTLE UNCERTAIN.
OVERALL...TEMPS WERE GOOD...DID USE A BLEND OF THE MET/MAV FOR TUES
NIGHT. /28/
.LONG TERM...A MORE EARLY WINTERISH TYPE WX PATTERN WILL BE TAKING
SHAPE IN THE MED RANGE/LONG TERM PART OF THE FORECAST. THE REGION
WILL SEE A MID LATITUDE CYCLONE EVOLVE ON WED AND LIFT NE THROUGH
THE MID ATLANTIC STATES. AS THAT OCCURS...COOL/WET CONDITIONS WILL
BE AROUND WED THEN DEPART TO THE NE. THEN...COLDER AIR WILL FILTER
INTO THE REGION BEHIND THE FRONT WED NIGHT INTO THU AND LIKELY
LINGER INTO THE WEEKEND. A FEW MORNINGS WILL LIKELY SEE FREEZING
TEMPS (FRI-SUN) WITH READINGS RUNNING SOME 10-15 DEGREES BELOW
NORMAL VALUES.
FOR WED...OUR CYCLONE WILL BE DEEPENING NICELY WITH THE HEAVY RAIN
E/SE OF THE FORECAST AREA. HOWEVER...STRONG ASCENT WILL REMAIN OVER
THE REGION FOR AT LEAST THE FIRST PART OF THE WED PERIOD AS THE COLD
CORE ALOFT MOVES OVER THE REGION. AS THAT OCCURS...THETA SURFACES
THROUGH A DEEP LAYER WILL QUICKLY RISE AND "SQUEEZE" OUT LEFT OVER
MOISTURE AND ALLOW FOR SOLID PRECIP CHANCES ON WED. OVERALL...THE
PRECIP WILL BE LIGHT AND TAPER TO MORE OF A MIX OF DRIZZLE/LIGHT
RAIN. TEMPS WED WILL BE TRICKY AS THERE ARE MODEL DIFFERENCES ON THE
TRACK OF THE SFC LOW AND TIMING. DUE TO THESE...I WILL JUST FOLLOW
THE GFS GUID FOR HIGH TEMPS WED.
BY WED NIGHT...ALL GUID AGREES THAT THE MAIN ASCENT AREA WILL BE
PUSHING OUT OF THE CWA AND THEY ALL STILL HOLD ONTO A FEW HUNDRETHS
OF LIGHT PRECIP. I WOULD LIKE TO REMOVE ALL POPS/WX. HOWEVER...THIS
IS THE PERFECT RECIPE FOR A FEW SITES GETTING .01-.02 AS STRONG CAA
DEVELOPS AND LOW LEVEL MOISTURE REMAINS RATHER DEEP WITH DECENT RH
VALUES STILL UP TO 700MB. DUE TO THIS...I WILL KEEP THE GUID POPS OF
30-40% AND MENTION DRIZZLE/LIGHT RAIN FOR WED EVENING. AS FOR
TEMPS...GUID HAS TRENDED COOLER AND I MADE SOME MINOR ADJ AND
LOWERED SOME AREAS AS RAW GUID AND BUFR SOUNDINGS WERE A GOOD BIT
COOLER THU MORNING.
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...COLD FRONT WILL CONTINUE TO MAKE ITS WAY THROUGH THE
REGION. BEHIND THE FRONT...AN AREA OF LIGHT TO MODERATE RAIN IS
FALLING AND WILL CONTINUE BEHIND THE FRONT. ALL MODELS SHOULD FRONT
AND RAIN SHOULD HAVE GOTTEN ALL THE WAY THROUGH THE CWA BY AROUND
18-19Z. WITH THE RAIN...MVFR TO IFR CONDITIONS WILL PREVAIL IN BOTH
CEILINGS AND VIS. ADDITIONALLY...WINDS WILL ABRUPTLY SHIFT TO
NORTHWEST TO NORTH AND INCREASE TO 10 TO 15 KT WITH GUSTS TO 20 KT
IN THE WAKE OF THE FRONT. THE FRONT IS EXPECTED TO REACH KGTR AND
KJAN BETWEEN 10 AND 13 UTC...AND KMEI AND KHBG BETWEEN 13 AND 16
UTC. ISOLATED THUNDERSTORMS WILL ALSO BE POSSIBLE IN SOME OF THE
HEAVIER RAIN AREAS. AFTER THE MODERATE RAIN MOVES THROUGH...TWO TO
THREE HOURS LIGHT RAIN WILL OCCUR WITH MVFR CEILINGS AND
VISIBILITIES. LOW CLOUDS WITH MVFR CEILINGS WILL CONTINUE THROUGH
MONDAY AFTERNOON...WITH CLEARING EXPECTED TO BEGIN FROM NORTHWEST TO
SOUTHEAST LATE MONDAY AFTERNOON INTO MONDAY EVENING. WINDS WILL
BEGIN TO SUBSIDE LATE MONDAY AFTERNOON AS WELL. GENERALLY VFR
CONDITIONS SHOULD RETURN FOR OVERNIGHT MONDAY NIGHT. THERE COULD BE
SOME LIGHT PATCHY FOG BUT THERE IS NOT EXPECTED TO BE ANYTHING
WIDESPREAD OR SHOULD CAUSE MUCH IN THE WAY OF PROBLEMS. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 57 38 57 47 / 100 3 30 86
MERIDIAN 60 35 58 49 / 100 3 32 90
VICKSBURG 57 41 56 46 / 61 3 30 84
HATTIESBURG 64 40 57 52 / 96 5 62 88
NATCHEZ 58 41 56 47 / 76 8 62 90
GREENVILLE 54 40 55 44 / 28 3 13 79
GREENWOOD 54 37 58 44 / 41 3 13 80
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
28/CME/
