Area Forecast Discussion
Issued by NWS Jackson, MS

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000
FXUS64 KJAN 261340 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
839 AM CDT TUE MAY 26 2015

.UPDATE...SENT A QUICK FORECAST UPDATE TO ADJUST HOURLY TEMPS...
WHICH WERE RUNNING AS MUCH AS 10 DEGREES TOO WARM IN SOME AREAS.
ALSO WITH THE MCS HAVING PUSHED ACROSS THE REGION...BACKED OFF ON
POPS FOR THIS MORNING ESPECIALLY ACROSS THE WESTERN HALF OF THE AREA
AND REMOVED MENTION OF THUNDER. STILL ASSESSING THE POTENTIAL FOR
ANY REDEVELOPMENT LATER IN THE DAY...AND WILL ADDRESS THIS IN THE
MAIN UPDATE IN AN HOUR OR TWO. /DL/

&&

.DISCUSSION... /ISSUED AT 423 AM CDT TUE MAY 26 2015/ SHORT
TERM...TODAY THROUGH WEDNESDAY NIGHT...LATEST VAPOR AND IR IMAGERY
SHOWED THE MAIN UPPER BROAD TROUGH CENTERED OVER THE PLAINS WITH
MEAN UPPER RIDGING NOTED ACROSS THE EASTERN SEABOARD. IT ALSO SHOWED
A WEAKENING LINEAR MCS MOVING ACROSS THE CWA. A SERIES OF SHORTWAVES
WAS ROTATING ACROSS THE BASE OF THE UPPER TROUGH FROM THE SOUTHERN
PLAINS TO THE MIDDLE MISSISSIPPI VALLEY. A STRONG NEGATIVELY TILTED
SHORTWAVE WAS MOVING ACROSS THE SOUTHERN PLAINS. DURING THE PAST 24
HOURS WE HAVE STARTED TO SEE SOME ISOLATED SPOTS OF 3 TO AROUND 4
INCHES...WHILE MOST LOCATIONS WERE SEEING FROM 0.5 TO AROUND 2
INCHES. AREA RADARS CONTINUED TO PICK OF A WEAKENING LINE STORMS
MOVING EAST ACROSS THE CWA. SURFACE AND UPPER AIR ANALYSIS CONTINUED
TO PICK UP DEEP GULF MOISTURE TRANSPORT WITH PWATS AROUND 1.8 TO 2
INCHES...WHICH WAS RESULTING IN VERY EFFICIENT RAINFALL MODE ACROSS
THE REGION OVERNIGHT. MODEL AND 00Z SNDGS WERE CONTINUING TO SHOW
SOME IMPRESSIVE FLOW INT THE MID TO UPPER LEVELS FOR LATE MAY ESP
WEST OF THE REGION.

FOR TODAY THE SHORTWAVE AFFECTING THE REGION OVERNIGHT WITH THE
CONVECTION WILL DISTURB ON ANY SEVERE SETUP FOR THE DAYTIME HOURS.
MODELS CONTINUE TO SHOW THAT THE SHOWERS AND EMBEDDED STORMS WILL
CONTINUE THROUGH THE MORNING HOURS. THIS WAS SHOWN BY THE HIRES
MODELS AND WILL PLAY HAVOC ON ANY INSTABILITY SETUP FOR THE DAY. AS
A MATTER OF FACT HIRES SHOWS THE BEST STORMS OFF THE COAST DURING
THE DAY. WPC STILL SHOWS AN EXCESSIVE RAINFALL POSSIBILITY FOR THE
AREA FROM EARLY TODAY THROUGH EARLY WEDNESDAY...WHICH SEEMS SENSIBLE
CONSIDERING THE PWATS AND STRONG MOISTURE TRANSPORT ACROSS THE
REGION.  FOR TONIGHT THE HIRES MODELS DO NOT SHOW MUCH OF ANYTHING
GOING ON OUR AREA...BUT THEY SHOW AN MCS MOVING SOUTHEAST WEST OF
THE REGION...WHICH MAY SEND A WEAK BOUNDARY INTO THE REGION DURING
THE DAY WEDNESDAY. TAKING A CLOSER LOOK AT WEDNESDAY THERE WILL BE
SOME DEEP LAYER SHEAR OF AROUND 20 KNOTS. THERE MAY BE A POTENTIAL
FOR SOME STRONG TO SEVERE STORMS. MODELS SHOWS SOME 7C LAPSE RATES
WITH MIDLEVEL 500 MB TEMPS AROUND -11C...-6 SHOWALTER INDEX..VT NEAR
30 AND 20 KNOTS OF DEEP SHEAR. SURFACE BASED CAPE WILL BE AROUND
4000-5000 JUST WEST OF THE REGION DURING THE DAY. SO WITH THIS IN
MIND WILL PUT A LIMITED GRAPHIC FOR THE FAR WEST FOR WEDNESDAY.
/17/

LONG TERM...THURSDAY THROUGH TUESDAY...SLIGHTLY WARMER THAN NORMAL
TEMPERATURES WITH DAILY CHANCES FOR RAIN WILL CONTINUE THROUGH THE
LONG TERM. THE SURFACE RIDGE FROM THE WESTERN ATLANTIC ACROSS THE
GULF COAST STATES WILL REMAIN IN PLACE THURSDAY AND FRIDAY WITH WEAK
RIDGING ALOFT FROM THE WESTERN GULF ACROSS THE SOUTHEAST STATES.
THIS WILL RESULT IN MORE ISOLATED TO SCATTERED DIURNAL COVERAGE OF
CONVECTION TO END THE WORK WEEK. A CLOSED LOW OVER THE NORTHERN
ROCKIES THURSDAY WILL TRACK EAST TO THE CENTRAL PLAINS BY SATURDAY
AND HELP DEVELOP A SURFACE LOW THAT WILL MOVE TO THE MID MISSISSIPPI
RIVER VALLEY BY SATURDAY EVENING. AS HEIGHTS LOWER AND WAA INCREASES
AHEAD OF THE LOW PRESSURE SYSTEM RAIN CHANCES WILL INCREASE FROM THE
WEST OVER OUR CWA LATE SATURDAY INTO SUNDAY. THIS GFS RUN IS AGAIN A
LITTLE DEEPER WITH THE TROUGH AND STRONGER WITH THE ASSOCIATED
SURFACE LOW THAN THE ECMWF AND CMC. THE CLOSED LOW/UPPER LEVEL
TROUGH WILL SHIFT SLOWLY EAST THROUGH TUESDAY. THE GFS BRINGS THE
WEAK COLD FRONT INTO OUR CWA MONDAY MORNING BEFORE STALLING IT
ACROSS OUR SOUTHEAST AS THE CLOSED LOW MOVES NORTHEAST AWAY FROM THE
REGION. THE ECMWF IS SLOWER AND WETTER OVER OUR CWA THROUGH TUESDAY
WITH NO REAL FRONTAL BOUNDARY. CONSENSUS SUGGESTS DECENT POPS SUNDAY
AND MONDAY WITH COOLER AND DRIER WEATHER ON TUESDAY. NORMAL LOWS RUN
IN THE MID 60S AND NORMAL HIGHS RUN 85 TO 87F. DUE TO MOISTURE
LEVELS REMAINING HIGH THROUGH THE PERIOD OVERNIGHT LOWS WILL BE
ABOVE NORMAL. AFTERNOON HIGHS WILL TOP OUT CLOSE TO NORMAL THROUGH
THE PERIOD. /22/

&&

.AVIATION...NUMEROUS SHRA AND SOME TSRA WILL AFFECT ALL TAF SITES
THROUGH THIS MORNING...THEN WILL BE MORE RESTRICTED TO THE EAST TAF
SITES FOR THIS AFTERNOON BEFORE MOSTLY EXITING THE REGION BY LATE
AFTERNOON. IN THE VERY MOIST AIRMASS...WIDESPREAD MVFR/OCNL IFR CIGS
WILL BE PREVALENT LATE TONIGHT THROUGH WEDNESDAY MORNING./17/

&&

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

$$

DL/17/22


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