[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 090602
SWODY1
SPC AC 090600

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1200 AM CST THU DEC 09 2004

VALID 091200Z - 101200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 45 SW
HUM 40 ENE JAN 40 S MSL 20 NNE GAD 35 W ATL 20 NW PFN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 SE DAB 50 SSE CTY
...CONT... 35 ESE BPT MLU 15 ESE POF 20 SW BLV 35 SSE SPI 10 WNW CMI
45 S SBN 20 S TOL 30 NW HLG 45 NE CRW 45 NW TRI 15 WSW AVL HKY 25 SE
LYH 15 NE RIC 15 ESE WAL.

...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN LA ACROSS PORTIONS OF
SERN MS AND MUCH OF AL AND THE WRN FL PNHDL...

...SYNOPSIS...
SIGNIFICANT LARGE SCALE TROUGH AMPLIFICATION WILL OCCUR ACROSS THE
MIDWEST AND MIDDLE MS VALLEY AREAS THIS PERIOD AS AN INTENSE SPEED
MAX AND ASSOCIATED SHORT WAVE TROUGH...CURRENTLY MOVING ACROSS THE
NRN ROCKIES...PROMOTE STRONG CYCLOGENESIS ACROSS IL/IND AREA BY
EARLY FRIDAY. IN ADVANCE OF THIS STRONG AMPLIFICATION...A
DEAMPLIFYING MID/UPPER LEVEL WAVE WILL EJECT ENEWD FROM THE LOWER MS
VALLEY TO THE MID ATLANTIC COAST. AS THE LEADING SHORT WAVE TROUGH
ACCELERATES NEWD ACROSS THE LOWER MS VALLEY EARLY IN THE PERIOD...A
MOIST AND WEAKLY UNSTABLE GULF AIR MASS IS EXPECTED TO SPREAD INLAND
ACROSS LA AND PORTIONS OF MS/AL AS WARM FRONT LIFTS NWD. LATER IN
THE DAY...AS THE SAME UPPER DISTURBANCE MOVES ACROSS THE
SOUTHEAST...A NARROW WARM SECTOR MAY DEVELOP ACROSS THE ERN
CAROLINAS. BY LATE TONIGHT...VERY STRONG FORCING FOR UPWARD MOTION
WILL ACCOMPANY THE AMPLIFYING UPPER TROUGH AND DEEPENING SURFACE LOW
ACROSS THE MIDWEST. MID LEVEL HEIGHT FALLS OF 120-150M WILL OCCUR
FROM THE LOWER OH VALLEY ACROSS THE TN VALLEY THROUGH FRIDAY MORNING
AND COULD SUPPORT STRONG CONVECTIVE DEVELOPMENT ACROSS THESE AREAS.

...LOWER MS VALLEY ACROSS SRN AL...
THERE ARE A NUMBER OF UNCERTAINTIES REGARDING THE FORECAST OF
INSTABILITY AND INLAND DEVELOPMENT OF THE WARM SECTOR ACROSS THIS
REGION TODAY. LATEST INDICATIONS SUGGEST THAT STRONG TO ISOLATED
SEVERE TSTMS MAY BE ONGOING AT THE START OF THE PERIOD FROM SERN LA
INTO PARTS OF SRN MS. AIR MASS ACROSS THESE AREAS WILL NOT BE
PARTICULARLY UNSTABLE TO SURFACE-BASED STORMS. HOWEVER...SHEAR AND
FORCING APPEAR TO FAVOR THE POTENTIAL FOR A FEW ELEVATED SUPERCELLS
WITH SOME CHANCE OF HAIL. THERE IS A CHANCE OF MARGINAL DIURNAL
DESTABILIZATION IN AREAS THAT REMAIN CLEAR OF RAIN THROUGH THE
MORNING...PERHAPS FROM THE SRN MS/AL BORDER AREAS ACROSS SRN AL AND
THE WRN FL PNHDL. EVEN AS THE MAIN FORCING WITH THE SHORT WAVE LIFTS
NORTHEAST OF THESE AREAS INTO LATE MORNING/EARLY AFTERNOON...A FEW
STORMS PERSISTING WITHIN TRAILING WEAK SURFACE TROUGH COULD TAP INTO
GREATER INSTABILITY. THIS ACTIVITY COULD POSE A THREAT OF A FEW
DAMAGING WIND GUSTS OR PERHAPS A TORNADO.

ETA MODEL IS FCSTG A PLUME OF STRONG DESTABILIZATION IN THE WAKE OF
THE MAIN PRECIPITATION SHIELD ASSOCIATED WITH THE EJECTING MID LEVEL
WAVE. THIS APPEARS TO BE A RESULT OF ACTIVE SHALLOW CONVECTION IN
THE MODEL...COUPLED WITH STRONG MID LEVEL COOLING AHEAD OF THE
ADVANCING DOWNSTREAM TROUGH. WHILE SOME INSTABILITY IS POSSIBLE IN
THE CORRIDOR FROM MS NEWD TO THE LOWER OH VALLEY LATE IN THE
DAY...IT IS UNCERTAIN WHETHER THIS INSTABILITY WILL BE SUFFICIENT
FOR ADDITIONAL SEVERE TSTM DEVELOPMENT DURING THE EVENING AND
OVERNIGHT /SEE BELOW/.

...ERN CAROLINAS...
A DIFFICULT FCST ACROSS THIS AREA AS WELL. HOWEVER...BOTH ETA AND
ETAKF...AS WELL AS THE LATEST NCEP-SREF...INDICATE SUFFICIENT
INSTABILITY /MUCAPE TO AT LEAST 1000 J/KG/ WILL PRECEED THE MID
LEVEL DISTURBANCE. THIS INSTABILITY APPEARS TO DEVELOP AS THE WARM
FRONT LIFTS NWD ACROSS SC AND ERN NC DURING THE AFTERNOON. WHILE ETA
AND GFS BOTH PRODUCE CONVECTIVE QPF ACROSS THESE AREAS...THE ETAKF
PRODUCES MUCH OF ITS QPF AWAY FROM THE COAST AND ALONG THE FRONTAL
ZONE WHERE INSTABILITY REMAINS NEGLIGIBLE. VERY STRONG FLOW ACROSS
THE REGION SUGGESTS THAT ANY STORMS THAT CAN FORM IN THE INSTABILITY
AXIS ACROSS ERN AREAS WOULD BE SEVERE. SUPERCELL POTENTIAL...WITH
SOME WIND AND TORNADO THREAT...MAY BE ENHANCED IN THE VICINITY OF
THE WARM FRONT...FRONTAL WAVE...FCST TO MOVE RAPIDLY ACROSS THE
REGION LATE IN THE AFTERNOON. HIGHER PROBABILITIES AND A LATER
UPGRADE TO SLGT RISK MAY BE NEEDED IF GREATER FCST CONSENSUS
EVOLVES.

...TN/OH VALLEYS LATE...
LITTLE CONSENSUS ACROSS THIS AREA AS WELL WITH LITTLE CONVECTIVE
DEVELOPMENT SHOWN BY LATEST GFS...BUT...AS NOTED ABOVE...STRONG
DEVELOPMENT POSSIBLE BASED ON THE LATEST ETA. LOW TO MID LEVEL LAPSE
RATES WILL STEEPEN SIGNIFICANTLY AS UPPER TROUGH EVOLVES THROUGH
LATE EVENING. TSTMS...MOST LIKELY DECOUPLED FROM THE BOUNDARY
LAYER...SHOULD INCREASE AS DYNAMIC FORCING INTENSIFIES. A FEW OF
THESE CELLS COULD PRODUCE SEVERE HAIL INTO EARLY FRIDAY.
HOWEVER...GIVEN UNCERTAINTIES AND TIME OF DAY...HIGHER HAIL
PROBABILITIES ARE NOT WARRANTED AT THIS TIME.

..CARBIN.. 12/09/2004

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.