000
FXUS64 KJAN 141018
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
413 AM CST TUE NOV 14 2006
.SHORT TERM(TODAY THROUGH WEDNESDAY)...SATELLITE IMAGERY/RUC
ANALYSIS SHOWS MID AND HIGH LEVEL CLOUDS SPREADING EAST ACROSS THE
CWA THIS MORNING. THESE CLOUDS ARE ASSOCIATED WITH A SHORTWAVE
TROUGH THAT WILL MOVE OVER OUR REGION THIS MORNING. THESE CLOUDS
WERE INCREASING TEMPERATURES BY SEVERAL DEGREES AS THEY MOVED INTO
THE CWA. REGIONAL RADARS INDICATED A FEW SPRINKLES OVER THE DELTA
ASSOCIATED WITH THE SHORTWAVE...BUT ANY SIGNIFICANT RAINFALL WILL
HOLD OFF UNTIL LATER TODAY. A MORE POTENT SHORTWAVE TROUGH WAS NOTED
OVER THE NORTHWEST CONUS THAT WILL DIVE SOUTHEAST AN INTENSIFY AS IT
APPROACHES OUR REGION TODAY. MODELS ARE FAIRLY SIMILAR WITH THIS
SHORTWAVE DIGGING OUT A VERY DEEP MID LEVEL TROUGH TONIGHT OVER THE
PLAINS AND TRACKING THE ASSOCIATED DEEPENING SFC LOW FROM THE
SOUTHERN PLAINS ACROSS ACROSS ARKANSAS AND NORTHERN MISSISSIPPI
WEDNESDAY. CONFIDENCE CONTINUES TO INCREASE THAT THIS STRENGTHENING
SYSTEM WILL BRING SEVERE WEATHER TO THE ARKLAMISS LATER TONIGHT
THROUGH WEDNESDAY MORNING. WARM ADVECTION WILL INCREASE FROM THE
WEST TODAY AHEAD OF THE DEVELOPING SYSTEM. A WARM FRONT WILL BEGIN
LIFTING NORTH FROM THE GULF. THE MODELS MAY BE MOVING THE WARM FRONT
NORTHWARD A LITTLE TOO FAST BUT LIGHT SHOWERS ARE EXPECTED TO
DEVELOP IN OUR WESTERN ZONES AND PARISHES BY NOON TODAY.
SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS EVENING AS WARM
ADVECTION CONTINUES TO INCREASE. LATEST GFS AND NAM12 STILL BRING
LOWER 60 SURFACE DEWPOINTS INTO OUR AREA EARLY WEDNESDAY AHEAD OF
THE SYSTEM. MLCAPES SHOULD RANGE 800-1400J/KG. STRONG DYNAMICS ARE
STILL EXPECTED WITH DEEP LAYER SHEAR GREATER THAN OR EQUAL TO 40KTS.
DURING THIS EVENING THE MAIN SEVERE RISK WILL BE WINDS AND HAIL...
BUT LOW LEVEL SHEAR RAPIDLY INCREASES WEDNESDAY MORNING WITH 0-1KM
HELICITIES OF NEAR 500 M^2/S^2 AND 0-3KM VALUES 600-800 M^2/S^2. THE
GREATEST RISK FOR TORNADOES STILL APPEARS TO DEVELOP SOUTH OF THE
I-20 CORRIDOR.
ALL MODES OF SEVERE ARE EXPECTED WEDNESDAY MORNING AS THE MID LEVEL
SPEED MAX OF 70KTS+ MOVES E BETWEEN I-20/HWY 82 DURING THE MORNING
WHILE ONGOING SUPERCELL STORMS FORM A SQUALL LINE. A LINEAR MCS
GENERALLY ALONG A KMEI-KMCB LINE WILL BEGIN TO ACCELERATE EASTWARD
ENHANCING DAMAGING WINDS FOR SERN MS DURING THE MIDDAY HOURS. THE
LINE SHOULD EXIT EASTERN MISSISSIPPI BY MID AFTERNOON WITH GUSTY W
WINDS OF 20-30 MPH...A FEW GUSTS IN THE COLD AIR COULD REACH 40 MPH.
A WIND ADVISORY WILL LIKELY BE ISSUED FOR WEDNESDAY AFTERNOON AND
EVENING LATER TODAY. /22/
.LONG TERM(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)...
WILL STILL BE DEALING WITH THE POTENT UPPER LEVEL THROUGH
THURSDAY...AND MODEL DISCREPANCIES WITH TIMING OF ITS MOVEMENT (AND
ASSOCIATED SURFACE FEATURES) EAST CONTINUE. FORTUNATELY...
DIFFERENCES ARE NOT AS MARKED AS THEY WERE A FEW DAYS AGO...BUT
STILL REPRESENT NOTICEABLE CHANGES IN SENSIBLE SURFACE WEATHER
DURING THIS TIME FRAME. THAT SAID...OUR FORECAST STICKS GENERALLY
WITH THE GFS SUGGESTION OF CONVECTION BEING ENTIRELY OFF TO OUR EAST
BY 00Z THURSDAY...WITH THE ACTUAL COLD FRONT CLEARING EASTERN ZONES
BY THIS TIME. MAY TAKE SEVERAL HOURS FOR TEMPS TO FALL OFF BEHIND
THE COLD FRONT...BUT WINDS WILL BE IMMEDIATELY QUITE GUSTY FROM THE
WEST BEHIND THE BOUNDARY. MOISTURE WRAPPING AROUND THE STRENGTHENING
CYCLONE TO OUR NORTHEAST WEDNESDAY EVENING WILL BRING LOWER CLOUDS
QUICKLY BACK INTO THE REGION...WITH A DECENT CHANCE OF AT LEAST
LIGHT RAIN FALLING ACROSS THE NORTHERN HALF OF ZONES BY LATE
EVENING. RAINFALL TOTALS WITH THE WRAP-AROUND PRECIP SHOULD BE
RATHER LIGHT AND MOST OF IT SHOULD BE EXITING THE CWA BY
DAWN...ALTHOUGH THE LOW CLOUD SHIELD SHOULD LAG BACK BEHIND THE
PRECIP. AS MENTIONED...WIND WILL REMAIN GUSTY THROUGH THE NIGHT AND
AT LEAST A LAKE WIND ADVISORY SHOULD BE NECESSARY ACROSS A GOOD
PORTION OF THE AREA...BUT WILL WAIT FOR LATER SHIFTS TO ISSUE.
GENUINE WIND ADVISORY NOT OUT OF THE QUESTION FOR THIS PERIOD AT
THIS POINT AS PROGGED 35 TO 40 KT 925 MB WINDS SHOULD BE USHERED TO
THE SURFACE RATHER EFFICIENTLY GIVEN COLD AIR ADVECTION REGIME.
EXPECTING LOWS RANGING FROM 40 TO 45 BY DAWN AND I ROSE 00Z MAV 1 TO
2 DEGREES IN SOUTHEAST ZONES...GOING CLOSER TO RAW MODEL OUTPUT AND
ENSEMBLE AVERAGES.
DEEP CYCLONE SHOULD CONTINUE TO MOVE OFF STEADILY TO THE NORTHEAST
THURSDAY AS IT PHASES WITH A WAVE OVER SOUTHERN CANADA. WORRIED
COLD-AIR STRATOCU COULD LINGER ACROSS AT LEAST EASTERN ZONES MUCH
LONGER THAN MAV GUIDANCE SUGGESTS...BUT I ONLY DELAYED ITS DEPARTURE
A LITTLE SLOWER THAN GUI FOR NOW GIVEN REMAINING TIMING AND MOVEMENT
QUESTION MARKS WITH THE DEEP CYCLONE. WINDS WILL SLACKEN A BIT...BUT
WILL STILL BE GUSTY FROM THE NORTHWEST WITH TEMPERATURES REMAINING
IN THE COOL 50S GENERALLY. CUT MAV GUIDANCE TEMPS IN NORTHEAST ZONES
A BIT BASED ON CLOUD EXPECTATION. POPS KEPT AT GUIDANCE WHICH
ADVERTISES ONLY A SLIGHT CHANCE OF LINGERING LIGHT RAIN IN NORTHEAST
ZONES FOR THE MORNING HOURS.
THE REST OF THE LONG TERM FORECAST IS MUCH MORE BENIGN IN COMPARISON
TO THE MASSIVE DISTURBANCE THAT WILL BE AFFECTING THE ARKLAMISS NOW
THROUGH THURSDAY. LOOKING FOR QUASI-NORTHWEST FLOW TO DEVELOP IN OUR
NECK-OF-THE-WOODS IN RESPONSE TO SUBTLE UPPER RIDGING UPSTREAM. OUR
REGION WILL LIKELY BE BRUSHED BY A FEW DISTURBANCES FRIDAY THROUGH
THE BEGINNING OF NEXT WEEK...WITH ACCOMPANYING COLD FRONTS SLIDING
SOUTH TO THE COAST. OVERALL PATTERN...AND MODEL CONSENSUS...DOES NOT
SUGGEST MUCH CHANCE OF RAIN WITH THESE SYSTEMS AS ANY PREFRONTAL
MOISTURE RETURN WILL BE MEAGER. TEMPS ARE A BIT MORE OF A QUESTION
MARK AS THE LOWER MS VALLEY WILL PROBABLY BE NEAR THE WESTERN
THRESHOLD OF SOME DECENT SURGES OF CP AIR. MAY TURN OUT THAT ONE OF
THESE SURGES COULD BRING FREEZING TEMPS TO MUCH OF THE REGION BEFORE
THE WEEKEND IS OUT...BUT I STUCK WITH MORE CONSERVATIVE MEX NUMBERS
FOR NOW GIVEN INHERENT UNCERTAINTY OF SITUATION. /BB/
&&
.AVIATION...A LAYER OF CLOUDS BETWEEN 2500-3000FT OVER THE DELTA
WILL SPREAD EAST THIS MORNING ASSOCIATED WITH A WEAK UPPER LEVEL
DISTURBANCE MOVING ACROSS THE REGION. THIS COMBINED WITH
VISIBILITIES AROUND 5SM WILL RESULT IN MVFR CONDITIONS AT MANY
LOCATIONS THIS MORNING THROUGH 15Z. CEILINGS WILL GRADUALLY INCREASE
ABOVE 3KFT AFTER 15Z. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL DEVELOP FROM THE WEST AFTER 18Z. CONDITIONS WILL DETERIORATE
TONIGHT AS AN INTENSE LOW PRESSURE SYSTEMS BRINGS WIDESPREAD
THUNDERSTORMS TO THE REGION. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 67 60 65 42 / 42 100 78 39
MERIDIAN 67 60 68 42 / 37 95 100 38
VICKSBURG 69 59 63 42 / 42 100 69 36
HATTIESBURG 68 61 70 43 / 55 92 100 17
NATCHEZ 71 60 63 40 / 56 100 63 22
GREENVILLE 66 58 61 40 / 31 100 79 56
GREENWOOD 66 58 64 41 / 30 100 80 62
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
22/BB
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