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630
FXUS64 KJAN 230403 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE JACKSON MS
1000 PM CST SAT NOV 22 2014

..THE RISK OF SEVERE WEATHER IN THE REGION REMAINS FOR SUNDAY
MORNING...

.UPDATE...SURFACE PRESSURES ARE STARTING TO DROP OFF THIS EVENING
ACROSS THE LOWER MS VALLEY IN RESPONSE TO PLAINS CYCLOGENESIS
BENEATH AN IMPRESSIVE PHASING OF SOUTHERN AND NORTHERN STREAM
DISTURBANCES. MODELS ARE TRENDING TOWARD ATMOSPHERIC LIFT PUSHING
THROUGH OUR REGION IN CONJUNCTION WITH THIS SYSTEM TO BE
CONCENTRATED JUST AHEAD OF A TROPOPAUSE FOLD. IT APPEARS THE ONSET
OF THIS TROPOPAUSE FOLD MANIFESTATION IS CURRENTLY AND RAPIDLY
ORGANIZING A POTENT SQUALL LINE...PUSHING OFF THE TX COAST AND INTO
THE NW GULF OF MEXICO. LATEST HIRES MODELS (ESPECIALLY THE HRRR)
DEPICT THIS SQUALL LINE CONTINUING TO EVOLVE AS IT ADVANCES THROUGH
THE NORTHWESTERN GULF OVERNIGHT. THESE MODELS ARE STILL UNSURE ON
HOW MUCH VIGOROUS CONVECTION WILL EXTEND NORTH OF THE COAST...AND
THIS DOES THROW A QUESTION MARK ON WHETHER CONVECTION OF SUFFICIENT
POTENCY TO PRODUCE SEVERE WEATHER WILL EXTEND MUCH INTO OUR CWA.
HOWEVER...I AM NOT YET SWAYED TO COMPLETELY BACK OFF THE SEVERE
WEATHER RISK BECAUSE THIS SYSTEM IS VERY DYNAMIC WITH HIGH WIND
SHEAR AND IN THE MIDST OF STREAM PHASING THAT COULD RESULT IN NWP
MODEL CURVEBALLS EVEN IN THE SHORT TERM. FOR ONE THING...THE FOCUSED
LIFT RIGHT AHEAD OF THE PV ANOMALY ASSOCIATED WITH THE TROP FOLD
SHOULD REQUIRE ONLY LIMITED INSTABILITY TO MAKE USE OF OTHER
PORTIONS OF THE PARAMETER SPACE FAVORABLE FOR SEVERE WEATHER. IN THE
END...THE GREATER ELEVATED RISK OF SEVERE STORMS (INCLUDING THE
POSSIBILITY OF TORS) WAS FOCUSED A BIT FURTHER SOUTH THAN
PREVIOUS...ALTHOUGH THE PRIOR LIMITED RISK NORTHERN EXTENT WAS LEFT
UNCHANGED.

THE POTENTIAL TIMING OF TROUBLESOME ACTIVITY SEEMS TO HAVE TIGHTENED
A LITTLE...FROM 5 AM THROUGH 11 AM...AND THIS WAS EXPRESSED IN THE
UPDATED HWO AND GRAPHICASTS. BESIDES FORECAST ADJUSTMENTS FOR
TONIGHT I DID DROP DOWN POPS QUICKER TOMORROW AFTERNOON WITH HIGHER
TEMPS AND MORE SUNSHINE. THIS...IN TURN...MAY LEAD TO EVEN GUSTIER
AFTERNOON WINDS THAN PREVIOUSLY ANTICIPATED AS THE SURFACE LOW
DEEPENS TO OUR NORTH. WITH THAT IN MIND THE SUBSEQUENT SHIFT MAY
NEED TO STRONGLY CONSIDER A WIND ADVISORY FOR TOMORROW AFTERNOON.
/BB/

&&

.PREV DISCUSSION... /ISSUED 348 PM CST SAT NOV 22 2014/

DISCUSSION

TONIGHT THROUGH MONDAY NIGHT...LATEST SATELLITE ANALYSIS SHOWED AN
INTENSE MIDLEVEL SHORT WAVE DEVELOPING INTO THE SOUTHERN PLAINS WITH
PLENTY OF JET ENERGY COMING IN FROM THE ROCKIES...WHICH WILL HELP IT
TO BECOME NEGATIVELY TILTED IN THE SHORT TERM. THE REGION WAS UNDER
SOUTHWEST FLOW AHEAD OF THIS FEATURE. OVER THE ARKLAMISS A POCKET OF
DRY AIR WAS NOTED ACROSS THE REGION FROM THE EAST WITH PWATS FROM
0.6 TO ONE INCH. PWATS WAS AS LOW AS .50 TO THE EAST OF THE REGION.
AREA RADARS WERE DRY ACROSS THE ARKLAMISS WITH THE DRY AIR IN PLACE
FROM THE EAST.

LOOKING AT THE MODELS RUNS. THERE SEEMS TO BE A CONSENSUS THAT THE
SEVERE CHANCES MAY BE HINDERED SLIGHTLY BY SEVERAL FACTORS. ONE IS
THE LACK OF MOISTURE TRANSPORT DUE TO NORTHERN GULF COASTAL
CONVECTION. THE OTHER WILL BE THE DOME OF DRY AIR TO THE EAST WHICH
MAY ALSO IMPAIR MOISTURE TRANSPORT. HOWEVER LIMITED INSTABILITY AND
HIGH SHEAR FROM STRONG JET ENERGY WILL CONTINUE OUR CHANCES OF
SEVERE WEATHER FOR MAINLY THE SOUTHERN AREAS ON SUNDAY MORNING. THE
PRIMARY RISK WILL BE DAMAGING WINDS AND POSSIBLE TORNADOES.

SO STARTING WITH TONIGHT THE SHORTWAVE OVER THE SOUTHERN PLAINS WILL
BECOME NEGATIVELY TILTED BY THE STRONG JET ENERGY AS IT PUSHES INTO
THE THE REGION EARLY SUNDAY MORNING. HIRES MODELS SHOWS THAT THE
RAINS WILL NOT REALLY DEVELOP ACROSS THE REGION UNTIL AFTER MIDNIGHT
DUE TO THE DRY AIR IN PLACE. HIRES MODELS SHOWS A QLCS TYPE BROKEN
SQUALL LINE(LONG HODOGRAPHS) PUSHING FROM THE NORTHERN GULF INTO
SOUTH HALF OF THE REGION. SO WITH THIS TYPE OF ENVIRONMENT WE WILL
PROBABLY LOOKING AT BOWING SEGMENTS...SUPERCELLS WITH STRONG SHEAR
FOR DAMAGING WINDS AND POSSIBLE TORNADOES.0-3KM SHEAR VECTORS
ORTHOGONAL TO THE LINE OF STORMS CONTINUE TO FAVOR MESOVORTEX
GENERATION AND A THREAT FOR TORNADOES/ENHANCED DOWNBURSTS.  ALSO WE
WILL GET SOME GOOD PRESSURE FALLS WITH THIS SYSTEM FOR THE
POSSIBILITY OF WAKE LOW ISSUES FOR GUSTY WINDS. THE PRIMARY TIMING
STILL LOOKS TO BE FROM 3 AM TO NOON. EXPECT THE STORMS TO LIFT OUT
BY THE AFTERNOON WITH SHOWERS IN ITS WAKE. MODELS POINT TO SOME
WINDY CONDITIONS ACROSS THE REGION FOR SUNDAY AFTERNOON INTO SUNDAY
EVENING UNTIL MIDNIGHT. LOOKING AT WINDS FROM 18-25 MPH WITH GUSTS
OF 30 TO 40 MPH. A WIND ADVISORY MAY BE NEEDED FOR THAT PERIOD.
EXPECT THE LAST OF THE SHOWERS TO PUSH OUT OF THE NORTH ON SUNDAY
EVENING. EXPECT DRY CONDITIONS FOR MONDAY AND MONDAY NIGHT AS THE
UPPER TROUGH SETTLES OVER THE REGION.

AS FAR AS TEMPS ARE CONCERN WENT CLOSE TO THE ALLBLEND AND COSMOS
BLENDS. AS FOR POPS WENT CLOSE TO ALL BLEND POPS FOR TONIGHT...HELD
TO CURRENT POPS FOR SUNDAY AND ADJUSTED COSMOS POPS FOR SUNDAY.

LONG TERM (TUESDAY THROUGH NEXT SUNDAY)...BEYOND THIS WEEKEND QUIET
AND RELATIVELY COOL WEATHER CONDITIONS WILL PREVAIL ACROSS THE AREA.

THE PERIOD WILL BEGIN WITH LONGWAVE UPPER TROUGHING OVER THE
ARKLAMISS REGION. MEANWHILE A SHARP UPPER RIDGE WILL SET UP ALONG
THE PACIFIC COAST OPENING THE DOORS FOR ANOTHER DOSE OF ARCTIC AIR
TO SPILL ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. THE BRUNT OF
THIS PARTICULAR COLD AIRMASS WILL REMAIN NORTH OF OUR AREA...BUT IT
WILL STILL HELP KEEP TEMPERATURES ABOUT 5-10 DEGREES BELOW NORMAL
FOR MUCH OF THE UPCOMING HOLIDAY WEEK.

CONDITIONS ARE EXPECTED TO REMAIN MOSTLY DRY THROUGH THE
WEEK...THERE MAY BE A FEW SYSTEMS THAT WILL PASS NORTH AND SOUTH OF
THE REGION DURING THE HOLIDAY WEEK. BOTH THANKSGIVING DAY AND BLACK
FRIDAY ARE LINING UP TO BE DRY AND UNSEASONABLY COOL AS A SPRAWLING
SURFACE HIGH BUILDS IN OVER THE MIDDLE PART OF THE COUNTRY. THESE
CONDITIONS LOOK TO CONTINUE INTO NEXT WEEKEND./17/
&

&&

.AVIATION...MVFR CEILINGS ARE PUSHING IN FROM THE SOUTHEAST THIS
EVENING AND SHOULD OVERTAKE ALL AREAS BY 1 TO 3 AM. LOCAL RADARS
WERE RELATIVELY QUIET AT 10 PM...BUT SHOWERS AND EMBEDDED STORMS
WERE APPROACHING FROM THE WEST AT THAT TIME AND STILL LOOK
NEGATIVELY IMPACT FLIGHT OPERATIONS IN ALL AREAS SUNDAY MORNING. AND
VFR CONDITIONS WERE BEING OBSERVED AT ALL TAF SITES THIS AFTN. CIGS
WL DROP TO IFR AREAWIDE BY 12Z. THE MOST INTENSE STORMS ARE EXPECTED
ACROSS THE PIB/HBG AREA. IN THE WAKE OF THE SHOWERS AND STORMS
STRONG GUSTY SW WINDS ARE EXPECTED SUNDAY AFTERNOON IN ALL AREAS.
LIGHTER WINDS CAN BE EXPECTED ACROSS THE SOUTHEAST HALF SUNDAY NIGHT
BUT STRONG GUSTY WINDS WILL CONTINUE OVER THE NORTHWEST HALF OF THE
AREA THROUGH SUNDAY NIGHT. /BB/22/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       58  75  51  61 /  86  91   8   6
MERIDIAN      58  72  55  62 /  70 100   8   7
VICKSBURG     58  77  48  62 /  95  74   8   5
HATTIESBURG   61  75  56  65 /  81 100   6   4
NATCHEZ       60  77  49  61 /  99  74   7   3
GREENVILLE    56  73  46  59 /  90  77  14   6
GREENWOOD     57  72  48  58 /  78  90  14   9

&&

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

$$

BB/17/22






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