584
FXUS64 KJAN 122322
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
622 PM CDT WED AUG 12 2020
UPDATE
UPDATED FOR 00Z AVIATION DISCUSSION
AVIATION
00Z TAF DISCUSSION:
SCATTERED STORMS WILL DIMINISH THROUGH THE EVENING BUT ANOTHER
ROUND WILL MOVE INTO THE REGION, ESPECIALLY THE DELTA, OVERNIGHT
AND CONTINUE SOUTH AND EAST THROUGH TOMORROW. THIS WILL LIKELY
AFFECT MOST TAF SITES AND MORE REFINEMENT WILL BE NEEDED IN LATER
FORECASTS. MVFR OR LOWER CEILINGS/VIS COULD ACCOMPANY STORMS BUT
VFR EXPECTED OUTSIDE OF STORMS. BETWEEN EARLY MORNING CONVECTION
AND POTENTIAL FOR MORNING STRATUS TO DEVELOP, MVFR CEILINGS ARE
POSSIBLE FROM ABOUT 09-15Z ACROSS THE REGION. DEPENDING ON WHERE
CONVECTION IS, SOME SITES SHOULD IMPROVE TO VFR IN THE LATE
MORNING OR EARLY AFTERNOON. /28/
DISCUSSION
TONIGHT AND THURSDAY: THANKS TO EARLY MORNING CLOUDINESS OVER OUR
DELTA REGION, LOCAL RADARS WERE QUIET THERE SO FAR THIS AFTERNOON.
CONVECTION THIS AFTERNOON WAS MOSTLY OCCURING ALONG A MOISTURE AXIS
ALONG AND JUST EAST OF INTERSTATE 55 AND WAS SLOWLY SPREADING EAST.
EXPECT THIS ACTIVITY TO CONTINUE INTO EARLY EVENING BEFORE
DISSIPATING BUT ADDITIONAL CONVECTION WILL DEVELOP THROUGH THE NIGHT
NORTH OF INTERSTATE 20 AND ESPECIALLY OVER THE DELTA REGION DUE TO
THE PRESENCE OF THE SHORTWAVE TROUGH. MID AFTERNOON WATER VAPOR
IMAGERY/RAP ANALYSIS STILL SHOWED A SHORTWAVE TROUGH EXTENDING FROM
THE MID MISSISSIPPI VALLEY INTO THE LOWER MISSISSIPPI VALLEY. THIS
FEATURE WILL SLOWLY SHIFT EAST THROUGH THURSDAY AND IS EXPECTED TO
COMBINE WITH OUR MOIST AIRMASS TO REDEVELOP CONVECTION OVER OUR
NORTHWEST LATER TONIGHT THAT WILL SPREAD ACROSS MUCH OF THE CWA
DURING THE DAY THURSDAY. THE STORMS WILL BE SLOW MOVERS AND COULD
PRODUCE LOCALLY HEAVY RAIN ACROSS THE AREA. THE FOCUS FOR HEAVY RAIN
THURSDAY WILL SHIFT BACK OVER EAST MISSISSIPPI AGAIN BY AFTERNOON.
THE RAIN AND ASSOCIATED CLOUD COVER WILL HOLD TEMPERATURES DOWN IN
THE UPPER 80S TO LOWER 90S. THIS WILL MITIGATE CONCERNS FOR HEAT
STRESS WITH THE POSSIBLE EXCEPTION OF OUR SOUTHWEST WHERE THE LOWEST
POPS AND HIGHEST TEMPERATURES ARE EXPECTED. PEAK HEAT INDEX VALUES
MAY REACH 105F BUT WL NOT INCLUDE MENTION OF THIS IN OUR HWO AT THIS
TIME. /22/
THURSDAY NIGHT THROUGH TUESDAY NIGHT
MID LEVEL TROUGHING WILL
PREVAIL ACROSS THE AREA THURSDAY NIGHT AND FRIDAY. THIS COMBINED
WITH PWATS AROUND 1.9-2.1 INCHES OVER MOST OF THE AREA, WILL PROMOTE
SCATTERED TO NUMEROUS SHOWERS FRIDAY AFTERNOON. HOTTER TEMPERATURES
ARE EXPECTED ON FRIDAY AND THIS COMBINED WITH HIGH HUMIDITY VALUES,
WILL CREATE HEAT INDICES AROUND 105 FOR AREAS MAINLY WEST OF I-55. A
HEAT GRAPHIC IS ALREADY OUT SO WILL CONTINUE TO ADVERTISE THIS. THE
GLOBAL MODELS SUGGEST THAT THE SHORT WAVE WILL MOVE EAST OF THE AREA
ON SATURDAY WITH DRIER AIR BUILDING IN. PWATS WILL BE AROUND 1.6-1.8
INCHES OVER MOST OF THE AREA, BUT STILL AROUND 2.0 INCHES IN THE
SOUTH, WHERE THE BEST CHANCE FOR AFTERNOON STORMS WILL EXIST.
A WEAK FRONTAL BOUNDARY WILL MOVE SOUTH ACROSS THE AREA SATURDAY
NIGHT INTO SUNDAY AND THIS WILL MAINLY USHER IN SLIGHTLY DRIER AIR
FOR SUNDAY. HEAT INDICES WILL CONTINUE TO BE NEAR 105 DEGREES MAINLY
OVER THE WESTERN HALF OF THE AREA, SO WILL CONTINUE TO ADVERTISE
THIS IN THE HWO AND GRAPHICASTS. EVEN WITH THE DRIER AIRMASS,
ISOLATED TO SCATTERED AFTERNOON STORMS WILL BE POSSIBLE SUNDAY
AFTERNOON. MONDAY AND TUESDAY WILL CONTINUE TO FEATURE ISOLATED TO
SCATTERED AFTERNOON STORMS AND HIGHS AROUND 90 DEGREES./15/
PRELIMINARY POINT TEMPS/POPS
JACKSON 74 89 73 89 / 36 72 39 60
MERIDIAN 74 90 73 88 / 28 77 46 71
VICKSBURG 75 91 74 92 / 42 68 28 45
HATTIESBURG 74 92 74 89 / 24 77 33 71
NATCHEZ 75 91 74 92 / 31 53 23 50
GREENVILLE 73 89 72 90 / 75 68 18 32
GREENWOOD 72 88 71 90 / 69 86 30 42
JAN WATCHES/WARNINGS/ADVISORIES
MS...NONE.
LA...NONE.
AR...NONE.
28
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