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000
FXUS64 KJAN 232058
AFDJAN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
400 PM CDT THU MAY 23 2013

.DISCUSSION...A BIT OF CONVECTION IS TRYING TO FORM CURRENTLY ACROSS
CENTRAL LOUISIANA IN AN AXIS OF HIGH INSTABILITY...MODEST MOISTURE
CONVERGENCE AND UPPER LEVEL ATMOSPHERIC LIFT. THIS IS BASICALLY
WHERE AN MCV (MESOSCALE CONVECTIVE VORTEX) EMBEDDED IN NORTHWEST
FLOW ALOFT IS IMPINGING ON A COLD FRONT OOZING SOUTH. BROAD SPECTRUM
OF GLOBAL NWP MODELS AND REGIONAL HIRES MODELS ARE STILL IN
DISAGREEMENT ON CONVECTIVE DEVELOPMENT THROUGH THIS EVENING IN OUR
VICINITY. OUR THINKING IS THAT THERE WILL LIKELY BE AT LEAST AN
ISOLATED STORM OR TWO IN SOUTHWEST ZONES LATE THIS AFTERNOON THROUGH
THIS EVENING WHICH COULD PRODUCE AT LEAST SOME BRIEF GUSTY WINDS OR
SMALL HAIL. THIS RISK WAS HIGHLIGHTED IN THE HWO. WE WILL ALSO HAVE
TO WATCH OUT FOR THE "WORST CASE SCENARIO" OFFERED BY A FEW HIRES
MODELS...WHICH IS A SMALL VIGOROUS THUNDERSTORM CLUSTER OR TWO
DEVELOPING OVER THE NEXT FEW HOURS AND PUSHING ACROSS SOUTHWEST HALF
OF ZONES THROUGH THIS EVENING. THIS WORSE CASE SCENARIO MIGHT BRING
A RISK FOR WIND GUSTS TO SEVERE LEVELS BUT FORTUNATELY LATEST TRENDS
SUGGEST THE WORST CASE SCENARIO NOT TOO LIKELY.

OTHERWISE FOR TONIGHT...ANTICIPATING THE COLD FRONT NOW SLIPPING
DOWN FROM THE NORTH TO PASS SLOWLY THROUGH MOST OF THE REGION BY
DAWN TOMORROW. ALTHOUGH THE AIR MASS TRYING TO COME IN BEHIND THE
BOUNDARY IS RELATIVELY COOL FOR THE DATE...CLOUDS AND SOME LINGERING
BREEZES WILL PREVENT OPTIMUM RADIATIONAL COOLING FROM OCCURRING. 12Z
MAV LOWS LOOKED GOOD...ADVERTISING A RANGE OF UPPER 50S NORTH TO MID
60S SOUTH. ALSO WORTH MENTIONING IS THAT THERE COULD BE SOME PATCHY
FOG IN SOUTHERN ZONES COME LATE TONIGHT...BUT FOG SHOULD DEFINITELY
NOT BE AS BIG OF AN ISSUE AS IT WAS THIS MORNING.

THROUGH TOMORROW AND INTO THE WEEKEND HIGH PRESSURE WILL TAKE UP
RESIDENCE OVER THE SOUTHEASTERN CONUS...ALTHOUGH THE COOLEST AND
DRIEST AIR WILL DEFINITELY BE CENTERED EAST AND NORTHEAST OR OUR
REGION. THE COLD FRONTAL BOUNDARY WILL STALL NOT TOO FAR TO OUR
SOUTHWEST AND COULD KICK OFF SOME MODEST CONVECTIVE ACTIVITY DURING
THIS TIME. FOR THAT REASON RAIN CHANCES WILL BE LOW...BUT NOT ZERO.
MORE OPERATIONALLY-SIGNIFICANT WILL LIKELY BE THE FACT THAT THE
CLOSE BOUNDARY AND INTERMITTENT CONVECTION TO OUR WEST SHOULD SHOOT
SOME HIGHER CLOUDS PERIODICALLY OUR WAY. THIS CLOUD COVER WILL
LIKELY KEEP TEMPERATURES A LITTLE WARMER TOMORROW NIGHT AND SATURDAY
NIGHT THAN THE EXTREMELY COOL 12Z MAV SUGGESTS. BUT EVEN RAISING 12
MAV LOWS FOR FRIDAY NIGHT A TOUCH SUGGESTS A FEW RECORD LOWS COULD
BE IN JEOPARDY FOR THE 25TH. HIGH TEMPERATURES SHOULD PROBABLY ONLY
BE A LITTLE BELOW AVERAGE IN MOST SPOTS...ALTHOUGH LOCATIONS UP
NORTH ALONG THE HIGHWAY 82 CORRIDOR COULD SEE HIGHS REMAINING IN THE
UPPER 70S TOMORROW.

THE FRONT WILL BE STARTING TO RETURN NORTH BY LATE SUNDAY AS A WEAK
DISTURBANCE PASSES TO OUR NORTH. THE INTERACTION OF THIS FRONT AND
THE DISTURBANCE WILL BRING CHANCES OF SHOWERS AND STORMS...BUT
MAINLY TO OUR NORTH. SO AFTER THIS EVENING WE HAVE KEPT THE FORECAST
DRY FOR ALL AREAS UNTIL AROUND THE MIDDLE OF NEXT WEEK. THE PREVIOUS
LONG RANGE DISCUSSION IS POSTED BELOW FOR REFERENCE. /BB/

&&

.PREV DISCUSSION... /ISSUED 415 AM CDT THU MAY 23 2013/

LONG TERM...(SUNDAY THROUGH THURSDAY) RIDGING BEGINS TO GIVE WAY
SATURDAY NIGHT WITH A SHORTWAVE MOVING THROUGH TO FLATTEN FLOW. THE
EURO IS ADVERTISING STRONGER FORCING WITH THIS WAVE AND BRINGS AN
AREA OF MOISTURE/PRECIP ACROSS NRN ZONES FOR SUNDAY. THE HIGHER POPS
CALLED FOR BY THE EURO FOR MONDAY AFTER THE WAVES PASSES LOOK A
LITTLE OUT OF WHACK...WEAK ISENTROPIC FLOW NOTWITHSTANDING...AND THE
MORE CONSISTENT DRY FORECAST PER THE GFS WILL BE FOLLOWED FOR NOW.
MODEL SOLUTIONS CONTINUE TO DIFFER IN THE FARTHER PERIODS OF THE
EXTENDED REGARDING PLACEMENT OF THE UPPER RIDGELINE AND SHORTWAVES
THAT PUSH THROUGH BUT THE GENERAL PATTERN WILL BE LOW LEVEL SLY FLOW
IN A REGION OF WEAK UPPER FORCING POSSIBLE DEPENDING ON WHERE THE
RIDGE/TROUGH POSITIONS SET UP. IN THIS TYPE OF REGIME THE CHANCE OF
AFTERNOON CONVECTION...EVEN WITHOUT SIGNIFICANT FORCING...WILL
GRADUALLY BE ON THE INCREASE DUE TO PERSISTENT SLY FLOW THAT WILL BE
IN PLACE. HOWEVER MODELS ARE ALSO SUGGESTING A POTENTIAL FOR CAPPING
DUE TO THE PROXIMITY OF THE UPPER RIDGE. DUE TO THESE UNCERTAINTIES
THE DRIER GFS WILL BE FOLLOWED FOR NOW. /03/

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL TONIGHT THROUGH
FRIDAY AND SATURDAY. A LINGERING FRONTAL BOUNDARY WILL PROVIDE THE
OPPORTUNITY FOR A FEW STORMS TO DEVELOP LATE THIS AFTERNOON AND
EVENING... ESPECIALLY OVER SOUTHWESTERN PORTIONS OF THE FORECAST
AREA... POTENTIALLY AFFECTING THE TVR/HEZ CORRIDOR. THERE COULD BE A
PERIOD OF IFR/MVFR STRATUS LATE TONIGHT AND EARLY FRIDAY MORNING IN
INCREASING NORTHEAST LOW-LEVEL FLOW AND COOL AIR ADVECTION...BUT THE
DRIER AIR AND INCREASED FLOW SHOULD LIMIT FOG POTENTIAL. IT APPEARS
THE GREATEST RISK FOR ANY FOG WOULD BE IN THE PIB/HBG AREA. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       63  83  52  84 /  15   6   2   2
MERIDIAN      60  82  46  84 /   9   2   0   0
VICKSBURG     64  82  54  85 /  29   7   5   6
HATTIESBURG   65  86  51  86 /  15   5   3   2
NATCHEZ       66  83  55  83 /  33   9   5   7
GREENVILLE    62  79  54  82 /  13   3   2   4
GREENWOOD     58  78  50  82 /   8   1   0   0

&&

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

$$

BB/EC/03