584
FXUS64 KJAN 130231 AAA
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
931 PM CDT MON AUG 12 2013
.DISCUSSION...A LINE OF CONVECTION CONTINUES TO MOVE ESELY ACROSS
NWRN PORTIONS OF THE CWA THIS EVENING. THESE STORMS HAVE BEEN STRONG
AT TIMES...NECESSITATING A FEW SPS'S. BUT WITH THE LOSS OF DAYTIME
INSTABILITY...THE GENERAL EXPECTATION IS FOR THE INTENSITY OF THESE
STORMS TO WANE. HOWEVER AT LEAST SOME ACTIVITY MAY PERSIST INTO THE
NIGHT. LATEST HRRR RUNS SUGGEST AT LEAST SOME SHOWERS AND POSSIBLY A
STORM COULD GET AS FAR SOUTH AS THE I-20 CORRIDOR AND LINGER BEYOND
MIDNIGHT. THE FORECAST WILL BE UPDATED TO REALIGN WX GRIDS TO
REFLECT THIS THINKING. ALSO TOOK OUT RAIN CHANCES SOUTH OF I-20 IN
AREAS THAT WERE WORKED OVER BY CONVECTION DURING THE LATE AFTERNOON
AND EVENING HOURS. UPDATED PRODUCTS ARE CURRENTLY BEING SHIPPED OUT.
/DL/
&&
.AVIATION...THUNDERSTORM ACTIVITY WILL DIMINISH AS WE GO THROUGH MID
TO LATE EVENING. MOST TAF SITES HAVE RECEIVED OR WILL RECEIVE SOME
RAINFALL THIS EVENING AND THIS SHOULD HELP TO SUPPORT MVFR TO
PERHAPS IFR FOG/STRATUS PRODUCTION LATE TONIGHT AND EARLY TUESDAY
MORNING. ANY FOG/STRATUS SHOULD MIX OUT DURING THE MID MORNING HOURS
WITH MOSTLY VFR CONDITIONS ANTICIPATED FROM LATE TUESDAY MORNING
THROUGH AFTERNOON. ANOTHER ROUND OF THUNDERSTORM ACTIVITY IS LIKELY
AT MOST SITES FROM TUESDAY AFTERNOON INTO TUESDAY EVENING. /EC/
&&
.PREV DISCUSSION... /ISSUED AT 330 PM CDT MON AUG 12 2013/
SHORT TERM...THROUGH WEDNESDAY NIGHT...
AFTERNOON WATER VAPOR IMAGERY SHOWED A SHORTWAVE DROPPING OUT OF
CANADA AND OVER THE NORTHERN PLAINS. THIS AND SEVERAL OTHER SHORT
WAVES WILL HELP DEEPEN AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS
THROUGH WEDNESDAY. THIS WL RESULT IN NORTHWEST FLOW ALOFT OVER OUR
REGION TUESDAY THROUGH WEDNESDAY NIGHT. THIS WILL SUPPORT THE
SOUTHWARD DRIFT OF A WEAK COLD FRONT INTO OUR CWA TUESDAY. THIS
FRONTAL BOUNDARY WILL BECOME THE FOCUS FOR DAILY CONVECTION.
COME TUESDAY AFTERNOON SCATTERED TO NUMEROUS STORMS ARE EXPECTED TO
DEVELOP ACROSS OUR CWA. FORECAST SOUNDINGS SUGGEST A LITTLE MORE
FAVORABLE POTENTIAL FOR A STRONG STORM OR TWO...ESPECIALLY ALONG THE
HIGHWAY 82 CORRIDOR WHERE THE BOUNDARY IS EXPECTED. PWS WILL BE
ABOVE TWO INCHES AND STORMS TRAINING ALONG AND AHEAD OF THE BOUNDARY
WILL LIKELY PRODUCE HEAVY DOWNPOURS. MODELS ARE SHOWING POTENTIAL
RAINFALL OF TWO TO FOUR INCHES ACROSS THE NORTH AND CENTRAL PORTIONS
OF THE AREA FROM TUESDAY MORNING THROUGH WEDNESDAY NIGHT. THE GFS
AND NAM WERE ALSO HINTING AT A POSSIBLE MCS DROPPING INTO OUR AREA
FROM THE NORTHWEST EARLY WEDNESDAY MORNING. THE FRONT IS EXPECTED TO
BE DRAPED ACROSS THE CWA FROM SOUTHEAST ARKANSAS TO EAST CENTRAL
MISSISSIPPI. SOMEWHAT COOLER AND DRIER AIR WILL FILTER INTO OUR
NORTHERN ZONES LOWERING RAINFALL CHANCES THERE.
AS THE UPPER LEVEL TROUGH DEEPENS THROUGH WEDNESDAY NIGHT...A
+1020MB HIGH WILL SETTLE FROM THE MID MISSISSIPPI AND OHIO VALLEYS
PUSHING THE WEAK COLD FRONT SOUTH OF HIGHWAY 84 BY THURSDAY MORNING.
THE PRECIPITATION DEVELOPMENT AND ASSOCIATED CLOUD COVER WILL MAKE
TEMPERATURES A LITTLE DIFFICULT THROUGH THE PERIOD. THE 12Z GFS MOS
HIGHS WERE AMONG THE HIGHEST ENSEMBLE MEMBERS AT MOST LOCATIONS
TUESDAY. HAVE CUT HIGHS SEVERAL DEGREES ACROSS THE NORTH...CLOSER TO
THE NAM MOS AND GFS ENSEMBLE MEANS. WITH THE COLD FRONT DROPPING
ACROSS OUR SOUTHERN ZONES WEDNESDAY NIGHT...LOWER 60S LOOK
REASONABLE IN THE NORTH THURSDAY MORNING. /22/
LONG TERM...SOME DRIER AIR WILL PUSH INTO THE REGION FROM THE NORTH
THURSDAY NIGHT INTO FRIDAY MORNING AS PWATS WILL BE FROM 1-1.5
INCHES. THIS WAS CONFIRMED BY AREA MODEL CROSS SECTIONS. WITH THE
FRONT BEING STATIONARY ACROSS THE SOUTH...A SERIES OF WEAK
DISTURBANCES WILL COME ACROSS THE REGION. THERE COULD BE A FEW
STRONG STORMS DURING THE PERIOD NEAR THE DECAYING FRONTAL BOUNDARY.
THIS WILL PROVIDE SOME CHANCE OF RAIN FOR THE REST OF THE PERIOD.
WITH THE LOWER PWATS DO NOT SEE THE RISK OF LOCALLY HEAVY RAINFALL
AT THIS TIME. THE UPPER TROUGH AXIS WILL DEVELOP OVER THE REGION
FROM FRIDAY THROUGH THE WEEKEND. THIS WILL BRING SOME 60S DEWPOINTS
AND TAKE A LITTLE HUMIDITY OUT OF THE AIR WITH THE SLIGHTLY MILDER
DAYS AND COOLER NIGHTS. HIGHS AFTER THE FRONT WILL BE GENERALLY IN
THE MID 80S TO LOWER 90S WITH LOWS BRINGING SOME NIGHT RELIEF OF
READINGS IN THE 60S TO AROUND 70. THIS PATTERN MAY BRING SLIGHTLY
BELOW NORMAL HIGHS AND LOWS FOR THIS TIME OF YEAR.
AS FAR AS MODEL TEMPS ARE CONCERNED ON WEDNESDAY USED A BLEND OF
COOLER EURO AND MEX TEMPS FOR HIGHS. THE EURO LOOKED TOO WARM ON
NIGHTLY LOWS. SO WENT CLOSE TO MEX TEMPS. ON DAILY HIGHS AFTER
WEDNESDAY WENT CLOSER TO SLIGHTLY WARMER MEX NUMBERS.
AS FAR AS POPS ARE CONCERNED WENT CLOSE TO MEX NUMBERS ON WEDNESDAY
INTO THURSDAY...WHICH WAS A LITTLE WETTER THAN THE EURO. FOR THE
REST OF THE WEEK THE EURO POPS WERE RATHER DRY WITH THE STATIONARY
FRONT AROUND SO WENT CLOSER TO WETTER MEX POPS./17/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DL/EC/22/17