218
FXUS64 KJAN 161040
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
440 AM CST SAT NOV 16 2024
..NEW DISCUSSION
DISCUSSION
ISSUED AT 440 AM CST SAT NOV 16 2024
TODAY AND TONIGHT:
SOME PATCHY FOG HAS DEVELOPED MAINLY IN LOW-LYING AREAS AND RIVER
VALLEYS THIS MORNING UNDER MOSTLY CLEAR SKIES. WIDESPREAD DENSE FOG
IS NOT EXPECTED, BUT MOTORISTS SHOULD BE CAREFUL OF REDUCED
VISIBILITY IF OUT EARLY THIS MORNING. UPPER-LEVEL RIDGING AND
SURFACE HIGH PRESSURE OVER THE REGION TODAY WILL PROMOTE WARMER
WEATHER COMPARED TO YESTERDAY UNDER MOSTLY CLEAR SKIES. TO THE WEST,
A CUTOFF LOW WILL DEVELOP AROUND NORTHERN MEXICO IN THE BASE OF A
POSITIVELY TILTED UPPER-LEVEL TROUGH. AS THE SURFACE HIGH PUSHES
FARTHER EAST AND THE TROUGH DEEPENS TO OUR WEST, FLOW WILL TURN OUT
OF THE SOUTHEAST AND SOUTH ACROSS OUR FORECAST AREA. THIS SHOULD
BOOST LOW-LEVEL HUMIDITY OVERNIGHT AND COULD LEAD TO A BETTER CHANCE
FOR AREAS OF FOG. WILL MONITOR TRENDS IN GUIDANCE, BUT A FOG GRAPHIC
MAY BE NEEDED FOR TONIGHT.
SUNDAY THROUGH FRIDAY:
A STRONG JET STREAK EXITING THE UPPER-LEVEL TROUGH WILL LEAVE THE
CUT OFF LOW HANGING BACK AROUND SOUTH TEXAS HEADING INTO MONDAY
BEFORE IT LIFTS INTO THE GREAT LAKES IN ADVANCE OF THE NEXT TROUGH.
THIS SYSTEM'S COLD FRONT WILL PUSH EAST INTO OUR AREA AS THE LOW
PULLS AWAY TO THE NORTH. AT THE SAME TIME, A SURGE OF TROPICAL
MOISTURE WILL BE CROSSING THE GULF AFTER THE DEMISE OF TROPICAL
STORM SARA. FORECAST SOUNDINGS SHOW RELATIVELY WEAK INSTABILITY AND
MOIST ADIABATIC LAPSE RATES AHEAD OF THE COLD FRONT'S ARRIVAL,
THOUGH DEEP-LAYER WIND SHEAR WILL BE INCREASING AS WELL. THERE IS A
MARGINAL RISK FOR SEVERE THUNDERSTORMS ACCOMPANYING THIS FRONT,
FOCUSED MAINLY AROUND THE MONDAY EVENING TIME FRAME AS THE FRONT
ARRIVES. IN ADDITION, THE TIGHTENING PRESSURE GRADIENT AHEAD OF THE
COLD FRONT WILL LIKELY INCREASE SOUTHERLY WINDS TO AROUND 15-20 MPH
GUSTING TO 30-40 MPH IN ADVANCE OF STORMS MONDAY. WE HAVE ISSUED A
LIMITED THREAT GRAPHIC HIGHLIGHTING THESE STRONG WINDS FROM MID-
MORNING INTO THE AFTERNOON HOURS.
MODELS ARE COMING INTO BETTER AGREEMENT WITH THE PATTERN IN THE WAKE
OF THE EARLY WEEK SYSTEM, INDICATING A RAPIDLY DEEPENING LOW SHOULD
DEVELOP OVER THE NORTHERN HIGH PLAINS AND MIDWEST TUESDAY INTO
THURSDAY. WHILE THE TRAJECTORY OF THIS NEXT SYSTEM DOES NOT APPEAR
TO INVOLVE POLAR AIR GETTING NUDGED SOUTHWARD TOWARD OUR REGION, THE
STRONG FLOW SHOULD NUDGE HIGH PRESSURE OUT OF THE INTER-MOUNTAIN
WEST TOWARD THE GULF COAST. ECMWF AND GFS SHOW 6-HR PRESSURE RISES
OF 5-8 MB AS THIS SYSTEM'S COLD FRONT BARRELS THROUGH, AND IT'S
LIKELY THAT ADDITIONAL STRONG GRADIENT WIND GRAPHICS WILL BE NEEDED
FOR THE WEDNESDAY INTO THURSDAY TIME FRAME IN OUR AREA AS A STRONG
PRESSURE GRADIENT IS MAINTAINED IN THE WAKE OF THE FRONTAL PASSAGE.
FOR NOW HAVE BLENDED WIND GUIDANCE HIGHER FOR WEDNESDAY TO ACCOUNT
FOR THIS. WINDS FROM THE NORTHWEST COULD BE AROUND 20-25 MPH WITH
GUSTS OF 35-40. AT THIS TIME, IT IS HARD TO HAVE CONFIDENCE IN THE
FROST AND FREEZE POTENTIAL BEHIND THIS COLD FRONT AS MODELS
GENERALLY MAINTAIN THE INCREASED PRESSURE GRADIENT INTO FRIDAY
MORNING. BUT IF AND WHEN THE SURFACE HIGH PRESSURE CENTER CAN SHIFT
EASTWARD ALONG THE COAST, WE COULD GET THE LIGHTER WINDS NEEDED TO
DROP TEMPS INTO THE LOWER 30S. BEST TIMING AT THIS POINT APPEARS TO
BE FRIDAY NIGHT/SATURDAY MORNING, BUT THERE COULD BE FURTHER CHANGES
AS THIS SYSTEM EVOLVES. /NF/
AVIATION
(06Z TAFS)
ISSUED AT 1140 PM CST FRI NOV 15 2024
VFR CONDITIONS WILL PREVAIL OVERALL THROUGH THE TAF PERIOD. THERE
COULD BE SOME PATCHY FOG DEVELOPMENT TONIGHT, BUT WIND AT SOME
SITES, NOTABLY JAN, GWO, AND GTR IS PREVENTING THE NECESSARY
TEMPERATURE DROPS TO ACHIEVE THIS. IF AND WHEN WINDS DIMINISH AT
THESE SITES SOME PATCHY FOG COULD DEVELOP. ADDITIONALLY, A WIND
SHIFT TO THE SOUTHEAST IS EXPECTED LATE MORNING INTO THE
AFTERNOON./SAS/
PRELIMINARY POINT TEMPS/POPS
JACKSON 74 53 76 61 / 0 0 0 0
MERIDIAN 73 48 74 56 / 0 0 0 0
VICKSBURG 74 53 79 62 / 0 0 0 0
HATTIESBURG 77 53 79 60 / 0 0 0 0
NATCHEZ 75 57 79 63 / 0 0 0 0
GREENVILLE 69 50 75 61 / 0 0 10 10
GREENWOOD 72 52 76 60 / 0 0 0 10
JAN WATCHES/WARNINGS/ADVISORIES
MS...NONE.
LA...NONE.
AR...NONE.
NF/SAS20
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