FXUS64 KJAN 251018
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
415 AM CST FRI DEC 25 2009
.SHORT TERM...TODAY THROUGH SATURDAY...FIRST OFF THIS MORNING...
MERRY CHRISTMAS! SECONDLY...DESPITE A FEW PATCHES OF DRIZZLE OVER
MAINLY THE EASTERN HALF OF THE FORECAST AREA EARLY THIS MORNING...
AND PERHAPS A SNOW FLURRY OR TWO SEEN ACROSS MY NORTHEAST ZONES...
LOOK FOR IMPROVING BUT COLDER CONDITIONS ACROSS THE FORECAST AREA ON
THIS CHRISTMAS DAY AS BRISK WEST TO SOUTHWEST WINDS CONTINUE TO
USHER A MUCH COLDER AND DRIER AIRMASS INTO THE FORECAST AREA.
WITH THE TIGHT PRESSURE GRADIENT REMAINING OVER THE CWA...A LAKE
WIND ADVISORY REMAINS IN EFFECT UNTIL 3 PM TODAY FOR MUCH OF THE
FORECAST AREA.
AS THE STRONG LOW PRESSURE SYSTEM RESPONSIBLE FOR THESE BREEZY
CONDITIONS LIFTS FURTHER TO THE NORTH THROUGH THE DAY...THESE GUSTY
WINDS WILL GRADUALLY SUBSIDE THROUGH THE MID AND LATE AFTERNOON
HOURS FROM SOUTH TO NORTH AS THE PRESSURE GRADIENT RELAXES OVER THE
REGION. IN ADDITION TO THIS...SKIES WILL ALSO BEGIN TO CLEAR FROM
SOUTHWEST TO NORTHEAST THROUGH THE MID AND LATE AFTERNOON
HOURS...WITH MOSTLY CLEAR SKIES EXPECTED TONIGHT INTO SATURDAY.
SPEAKING OF TONIGHT AND SATURDAY...HIGH PRESSURE WILL QUICKLY BUILD
INTO AND ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. WITH CLEARING
SKIES EXPECTED TONIGHT AND WINDS EASING UP...THE MERCURY SHOULD FALL
INTO THE MID AND UPPER 20S IN MOST LOCATIONS EARLY SATURDAY
MORNING. ALTHOUGH MOSTLY CLEAR SKIES WILL BE OBSERVED ACROSS THE
FORECAST AREA SATURDAY...SOME HIGH CLOUDS WILL BEGIN TO FILTER EAST
NORTHEAST INTO MAINLY CENTRAL AND SOUTHERN PORTIONS OF THE REGION AS
YET ANOTHER LOW PRESSURE SYSTEM BEGINS TO DEVELOP OVER THE WEST
CENTRAL GULF OF MEXICO. HIGH TEMPERATURES WILL ALSO BE A TAD WARMER
SATURDAY AFTERNOON AS THE FLOW OVER THE AREA BECOMES MORE SOUTH TO
SOUTHEASTERLY DURING THE DAY. /19/
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...COOLER THAN NORMAL
TEMPERATURES WILL CONTINUE THROUGH TUESDAY WITH NEAR NORMAL
TEMPERATURES EXPECTED FOR THE END OF THE WEEK. ONLY A SLIGHT CHANCE
OF RAIN IN THE SOUTH IS EXPECTED FOR SATURDAY NIGHT INTO SUNDAY
BEFORE CHANCES FOR A MORE WIDESPREAD RAIN INCREASE FOR THE MIDDLE OF
THE WEEK. FOR SATURDAY NIGHT...THE LARGE UPPER LEVEL VORTEX WILL BE
SPINNING OVER THE GREAT LAKES REGION BUT SENDING US A SHORTWAVE
WHILE AT THE SAME TIME A DISTURBANCE IN THE SOUTHERN BRANCH OF THE
JET STREAM MOVES EAST FROM THE SOUTHERN PLAINS. AS A RESULT A
REINFORCING SHOT OF COOL DRY AIR WILL BE SINKING OVER OUR REGION
WHILE THE SOUTHERN DISTURBANCE HELPS DEVELOP A WEAK SURFACE LOW OVER
THE GULF AND SENDS OVERRUNNING MOISTURE NORTHWARD. THE ECMWF
CONTINUES TO BE RATHER DRY WITH THIS SYSTEM BUT THE NAM AND GFS
BRING LIGHT QPF INTO OUR SOUTHERN ZONES AFTER MIDNIGHT AND THROUGH
SUNDAY MORNING. THE COLDEST TEMPERATURES OF THE NIGHT SHOULD BE WELL
NORTH OF THE MEASURABLE PRECIP...NORTH OF INTERSTATE 20 SO WL
MENTION THE SLIGHT CHANCE OF LIGHT RAIN AND NO WINTRY MIX WITH THIS
PACKAGE. THE LIGHT RAIN WILL SHIFT SOUTH OF OUR AREA DURING THE
AFTERNOON AS THE DISTURBANCE AND SFC LOW SHIFT EAST. SUNDAY THE
UPPER VORTEX WILL ALSO BE FINALLY LIFTING OUT TO THE NORTHEAST WHILE
ANOTHER LARGE CLOSED LOW DROPS SOUTH DOWN THE WESTERN CONUS. THIS
WILL RESULT IN NEAR ZONAL FLOW ALOFT OVER OUR REGION MONDAY BUT
SHORTWAVE RIDGING SURFACE AND ALOFT IS EXPECTED TO DEVELOP OVER OUR
REGION MONDAY NIGHT INTO TUESDAY. THIS SHOULD BRING US SOME WARMER
TEMPS TUESDAY ALTHOUGH THE SURFACE HIGH WILL BE CENTERED NORTH OF
OUR REGION KEEPING OUR REGION UNDER A DRY NORTHERLY LOW LEVEL FLOW.
MOISTURE AND CLOUDS WILL INCREASE FROM THE WEST TUESDAY AS THE LARGE
UPPER LEVEL LOW BEGINS SWINGING EAST ACROSS THE DESERT SW. BOTH THE
GFS AND ECMWF BRING PRECIPITATION BACK INTO OUR CWA TUESDAY NIGHT
BUT THIS TIME IT'S THE GFS WITH STINGY QPF AMOUNTS. THE ECMWF IS
STRONGER WITH THE SHORTWAVE TROUGH THAN THE GFS AND DEVELOPS A SFC
LOW FARTHER NORTH OVER THE WESTERN GULF. OVERALL...BOTH MODELS ARE
WARMER TUESDAY NIGHT WITH CRITICAL THICKNESSES JUST NORTH OF OUR
AREA AND WELL NORTH OF WHERE THE SIGNIFICANT RAINFALL IS EXPECTED.
AGAIN WL NOT INCLUDE MENTION OF WINTRY MIX PRECIPITATION WITH THIS
PACKAGE BUT FUTURE MODEL RUNS MAY END UP TRENDING COLDER. BY
WEDNESDAY NIGHT BOTH GFS AND ECMWF HAVE SFC LOWS JUST SOUTH OF OUR
CWA BUT WITH THE ECMWF BEING OVER SOUTHERN LOUISIANA AND THE GFS
SOUTH OVER THE NORTHERN GULF WATERS. THE RAIN WILL END FROM THE WEST
THURSDAY AS THE SFC LOW AND SHORTWAVE TROUGH SHIFT EAST. THE ECMWF
HAS A SIGNIFICANTLY LARGER AMPLITUDE UPPER LEVEL TROUGH OVER THE
CENTRAL CONUS FRIDAY AND IS MUCH COLDER OVER OUR REGION THAN THE GFS
BUT FRIDAY LOOKS DRY. /22/
&&
.AVIATION...WIDESPREAD MVFR CEILINGS ARE BEING OBSERVED AT TAF SITES
ACROSS THE REGION THIS CHRISTMAS DAY MORN. THESE CEILINGS WILL
CONTINUE THROUGH MOST OF THE MORNING HOURS TODAY...BUT BEGIN TO
IMPROVE TO VFR STATUS FROM SOUTHWEST TO NORTHEAST THROUGH THE
AFTERNOON AS THE STRATUS DECK GRADUALLY LIFTS NORTHEASTWARD AND OUT
OF THE REGION. VFR CONDITIONS WILL THEN PREVAIL AT ALL SITES FROM
THIS EVENING AND THROUGH THE OVERNIGHT HOURS INTO SATURDAY MORNING.
GUSTY WEST TO SOUTHWEST WINDS WILL ALSO GRADUALLY SUBSIDE THROUGH
THE DAY AND OVERNIGHT HOURS AS THE STRONG LOW PRESSURE SYSTEM LIFTS
NORTHWARDS ALLOWING THIS TIGHT PRESSURE GRADIENT OVER THE REGION TO
FINALLY RELAX. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 44 27 53 31 / 1 0 4 14
MERIDIAN 46 27 54 31 / 1 0 4 14
VICKSBURG 43 29 53 32 / 1 0 4 13
HATTIESBURG 48 28 56 34 / 0 0 8 28
NATCHEZ 44 29 54 33 / 0 0 8 30
GREENVILLE 40 29 49 28 / 1 1 3 9
GREENWOOD 41 28 49 29 / 1 1 3 9
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...LAKE WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR MSZ018-019-
025>054-059>062.
LA...LAKE WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR LAZ007>009-
015-016-023>026.
AR...LAKE WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR ARZ074-075.
&&
$$
19/22/19
