Area Forecast Discussion
Issued by NWS Jackson, MS

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000
FXUS64 KJAN 211528 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE JACKSON MS
1030 AM CDT THU AUG 21 2014

.UPDATE...ROSE POPS SLIGHTLY THROUGH THE REST OF THE DAY IN MAINLY
THE WESTERN HALF OF ZONES. IN SOME OF THOSE WESTERN ZONES ALSO
LOWERED HIGH TEMPERATURE EXPECTATIONS A TOUCH. /BB/

&&

.DISCUSSION...VISIBLE SATELLITE ANALYSIS REVEALS A MESOSCALE
CONVECTIVE VORT (MCV) LEFTOVER FROM YESTERDAYS CONVECTION CURRENTLY
SPINNING OVER NE LA...EMBEDDED JUST TO THE WEST OF THE UPPER LEVEL
HIGH CENTER AFFECTING THE LOWER MS VALLEY REGION. DESPITE THE
PREVAILING RIDGE INFLUENCE...ISOLATED TO LOCALLY SCATTERED MIDDAY
THROUGH AFTERNOON SHOWERS AND THUNDERSTORMS LOOK TO BE POSSIBLE
ACROSS MAINLY THE WESTERN HALF OF ZONES OWING TO THE PRESENCE OF
SAID MCV. LATEST HRRR PAINTS THIS PICTURE QUITE WELL ALTHOUGH IT IS
POSSIBLE THOSE SOLUTIONS ARE A LITTLE OVERDONE. EXPECTING
CLOUDS/PCPN TO KEEP TEMPS DOWN A LITTLE IN WESTERN ZONES SO MAX
READINGS DROPPED THERE A DEGREE OR TWO. MORNING WET MICROBURST
CHECKLIST SUGGESTED MODERATE POTENTIAL FOR LOCALLY SEVERE DOWNBURSTS
GIVEN TEMPERATURES IN THE MID 90S SO CONVECTION WILL BE MONITORED
CLOSELY FROM THAT STANDPOINT...ALTHOUGH POTENTIAL STILL NOT DEEMED
HIGH ENOUGH TO INCLUDE MENTION IN THE HWO. /BB/

&&

.PREV DISCUSSION... /ISSUED 400 AM CDT THU AUG 21 2014/

SHORT TERM...TODAY THROUGH FRIDAY NIGHT...A LITTLE WARMER EACH DAY
WITH AFTERNOON HEAT INDEX VALUES REMAINING THE MAIN CONCERN. EARLY
MORNING SURFACE ANALYSIS HAD A 1019MB RIDGE CENTERED OVER THE GULF
COAST. EARLY MORNING WATER VAPOR IMAGERY/RUC ANALYSIS SHOWED THE
CIRCULATION AROUND A 592DAM HIGH CENTERED OVER OUR AREA. THIS MID
LEVEL HIGH WILL STRENGTHEN FURTHER TODAY AND REMAIN CENTERED OVER
OUR CWA THROUGH FRIDAY NIGHT. TOGETHER RIDGING SURFACE AND ALOFT
OVER OUR REGION WILL ALLOW FOR A SLOW WARMING TREND INTO THE
WEEKEND. A RATHER MOIST AIRMASS WILL REMAIN OVER OUR AREA WITH PWS
OF AN INCH AND THREE QUARTERS TO TWO INCHES. THIS WILL HELP MAINTAIN
UPPER 60 TO LOWER 70 DEGREE DEW POINTS DURING THE HOTTEST PART OF
THE DAY. THE COMBINATION OF TEMPERATURES IN THE MID TO UPPER 90S
WITH THE HIGH RELATIVE HUMIDITY WILL RESULT IN MAXIMUM HEAT INDEX
VALUES OF 101-104F TODAY AND 102-106 FRIDAY. GFSMOS GUIDANCE WAS
AGAIN A LITTLE TOO WARM AND LEANED TOWARD A BLEND OF THE NAM AND
ECMWF MOS GUIDANCE FOR AFTERNOON HIGHS EACH DAY. MODEL CONSENSUS
STILL HINTS AT LATE AFTERNOON SEA BREEZE CONVECTION TRYING TO DRIFT
UP INTO OUR SOUTHERN ZONES. HAVE CARRIED ISOLATED WORDING IN THE
SOUTHWEST TODAY AND ONLY IN OUR SOUTHEAST MOST ZONES FRIDAY
AFTERNOON. RAIN CHANCES WILL REMAIN VERY LOW ELSEWHERE THROUGH THE
PERIOD. /22/

LONG TERM...SATURDAY THROUGH WEDNESDAY...THROUGH THE WEEKEND HEAT
AND HUMIDITY WILL BE BE THE PRIMARY ISSUE AS MEAN RIDGING CONTINUES
THROUGH SUNDAY...WHICH WILL BRING CLASSIC AUGUST SUMMER MUGGY
CONDITIONS. 850MB TEMPS WILL BE IN THE UPPER 20S TO AROUND 30C. THIS
WILL BRING TEMPS IN THE MID TO UPPER 90S THROUGH THE WEEKEND. WITH
LOWS IN THE 70S HEAT INDICES WILL BE A CONCERN. HEAT INDICES WILL BE
AROUND 100 TO 107 ON SATURDAY AND SUNDAY. WITH STRONG SUBSIDENCE
RAIN CHANCES WILL BE RATHER SCARCE THROUGH SUNDAY. AS WE GO INTO
NEXT WEEK MOISTURE WILL BUILD ACROSS THE REGION FROM THE EAST. THIS
WILL GIVE THE REGION A BREAK IN WARM AFTERNOON HIGH TEMPERATURES.
THUS 850MB TEMPS WILL COOL SOME INTO THE MIDDLE 20SC. RAIN CHANCES
WILL PICK UP AS DEEP TROPICAL MOISTURE BUILDS ACROSS THE REGION.
PWATS WILL INCREASE TO AROUND 2.2 INCHES. THERE WILL BE DECENT
INSTABILITY FOR SOME CONVECTIVE CHANCES FROM MONDAY THROUGH
WEDNESDAY WITH SOME LOCALLY HEAVY RAINFALL POTENTIAL. THE MEAN
RIDGING WILL FLUCTUATE SOME DURING THE UPCOMING WORK WEEK.

AS FAR AS THE TROPICS ARE CONCERN MODELS ARE KEEPING TROPICAL
SYSTEMS AWAY FROM THE GULF OF MEXICO AND PUSHING POSSIBLE TROPICAL
SYSTEMS OFF THE EAST COAST.

AS FAR AS MODEL DIFFERENCES ARE CONCERN MOST OF THE ENSEMBLES...
EURO...NAVY AND UK MODELS KEEP THE MEAN RIDGE DOMINANT OVER OUR
REGION. THE GFS TRIED TO BRING AN UPPER TROUGH OVER THE CENTRAL
PLAINS AND EVENTUALLY PUSHED A FRONT TOWARD THE REGION FOR THE LATER
PART OF THE WORK WEEK...WHICH SEEMS TO BE AN OUTLIER. MODELS WERE IN
GENERAL AGREEMENT WITH THE WEEKEND HEAT AND INCREASE IN TROPICAL
MOISTURE FROM THE EAST FOR NEXT WEEK.

AS FAR AS POPS AND TEMPS ARE CONCERN WENT CLOSE TO MEX AND GMOS
GUIDANCE FOR THE PERIOD./17/

&&

.AVIATION...VFR CONDS CURRENTLY PREVAIL AT ALL TAF SITES AND WILL
CONTINUE AT MOST INTO THE EVENING. ISOLATED SHOWERS/STORMS ARE PSBL
AT MAINLY IN W TO SW MS...WHICH COULD BRING DOWN KGLH/KJAN TO
MVFR/IFR CEILINGS BRIEFLY AROUND 20-23Z. WINDS WILL BE LIGHT MAINLY
FROM THE W TO SW AROUND 4-8KTS THIS AFTERNOON. /DC/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       96  73  97  73 /  14   6   7   5
MERIDIAN      96  72  97  73 /   8   6   9   5
VICKSBURG     94  73  97  72 /  26   6   5   4
HATTIESBURG   97  73  98  74 /  14  12  20   9
NATCHEZ       92  74  95  73 /  33  11  13  10
GREENVILLE    95  74  97  74 /  11   5   5   4
GREENWOOD     96  73  97  73 /   8   5   5   4

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&

$$

BB/DC/22/17




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