[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 190547
SWODY1
SPC AC 190502

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1102 PM CST FRI MAR 18 2005

VALID 191200Z - 201200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 50 ENE
CRP VCT 55 N VCT 40 E CLL 40 NNW POE 10 WSW HEZ 40 SE MCB 30 W BVE.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 S CRP 30 WSW COT
10 ESE BWD 50 N FTW 60 W MEM 50 SSW HUF 20 E MMO 15 S AZO 20 SW CLE
15 WSW PKB 35 N HSV 15 WNW TOI 25 W PFN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 SSE OAJ 20 SSE
ORF.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 NW OTH 60 ESE DLS
60 W BOI 55 NW ENV 45 SE ELY 30 NW NID 25 W BFL 20 S MRY.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN TX AND THE
LWR MS VLY...

...SYNOPSIS...
LARGE SCALE FLOW OVER THE CONUS WILL REMAIN PROGRESSIVE AND BECOME
MORE AMPLIFIED BY THE END OF THIS FCST PERIOD AS ONE SHORT WAVE
TROUGH MOVES EAST ACROSS THE MIDWEST/OH VLY AREAS...UPPER RIDGING
BUILDS ACROSS THE INTERMOUNTAIN WEST AND NRN ROCKIES...AND ONSHORE
FLOW STRENGTHENS OVER CA AND THE PACIFIC NORTHWEST. TRAILING SEGMENT
OF THE SHORT WAVE TROUGH CROSSING THE MIDWEST/MS VLY AREAS WILL
MAINTAIN AN AXIS OF WEAK LOW LEVEL CONVERGENCE SPREADING SEWD INTO
THE LWR MS VLY AND UPPER TX GULF COAST TODAY. THIS RESIDUAL LOW
LEVEL BOUNDARY WILL BE TOPPED BY MODEST MID LEVEL WLY FLOW COMPRISED
OF A SERIES OF LOW AMPLITUDE UPPER WAVES. THE FIRST OF THESE
WAVES...MOVING ACROSS S TX EARLY TODAY...WILL CONTINUE EAST ACROSS
THE MS DELTA REGION THROUGH THIS AFTERNOON. THE NEXT
DISTURBANCE...CURRENTLY CROSSING THE LWR CO RIVER VLY...WILL
APPROACH SCNTRL TX AND THE UPPER TX GULF COAST LATER TODAY AND 
TONIGHT.

...SERN TX AND SRN LA/MS...
A TRICKY FCST FOR SEVERE TSTMS ACROSS THESE AREAS TODAY AS FOCUSING
MECHANISMS FOR STRONG ASCENT OVER THE REGION WILL REMAIN A BIT
AMBIGUOUS. AS MENTIONED ABOVE...AXIS OF WEAK LOW LEVEL CONVERGENCE
ASSOCIATED WITH THE UPPER SHORT WAVE TROUGH AND SURFACE CYCLONE
CROSSING THE MIDWEST WILL MOVE INTO THE LWR MS VLY DURING THE DAY.
STRONGER FORCING FOR DEEP LAYER ASCENT ALONG THIS FEATURE WILL
LIKELY BE LOCATED OVER THE MS VLY AREA FROM NERN LA INTO NRN/CNTRL
MS EARLY IN THE PERIOD WHERE PHASING BETWEEN A MIDDLE STREAM SHORT
WAVE TROUGH AND A SRN STREAM IMPULSE WILL OCCUR. INSTABILITY EAST OF
ANTICIPATED ONGOING CONVECTION IS NOT EXPECTED TO BE PARTICULARLY
HIGH GIVEN PRESENT AIR MASS AND LIMITED HEATING DUE TO CLOUD COVER.

CLEARING AND WEAK SHORT WAVE RIDGING AFTER THE PASSAGE OF THESE
FIRST MID/UPPER LEVEL DISTURBANCES WILL ALLOW FOR STRONG
DESTABILIZATION ALONG THE RESIDUAL LOW LEVEL BOUNDARY FROM LA WWD TO
THE TX COASTAL PLAIN BY AFTERNOON. SURFACE TEMPS IN THE 70S AND
DEWPOINTS IN THE 60S...TOPPED BY RELATIVELY COOL AIR ALOFT...WILL
RESULT IN SBCAPE VALUES POSSIBLY APPROACHING 2000 J/KG FROM VCT TO
HOU TO LCH. GIVEN THIS MAGNITUDE OF INSTABILITY...AND THE PRESENCE
OF MODEST WLY MID LEVEL FLOW ATOP WEAK LOW LEVEL WINDS...ANY
DEVELOPING STORM WILL HAVE A GOOD CHANCE AT PRODUCING LARGE HAIL AND
HIGH WINDS.

A COUPLE OF SCENARIOS ARE POSSIBLE WHICH LEAD TO THE GREATER
PROBABILITY OF SEVERE STORMS. 1) EARLY ACTIVITY ALONG THE BOUNDARY
OVER SWRN MS/ERN LA...AND ASSOCIATED WITH THE LEADING SHORT WAVE
TROUGHS...BACKBUILDS INTO STRONGER INSTABILITY AND BECOMES
SURFACE-BASED FROM LATE MORNING INTO THE AFTERNOON ACROSS PORTIONS
OF CNTRL/SRN LA...AND/OR 2) PERSISTENT CONVERGENCE AND HEATING ALONG
RESIDUAL BOUNDARY...OR OUTFLOW FROM MORNING CONVECTION... PROVIDES A
FOCUS FOR LATE AFTERNOON/EVENING CONVECTIVE INITIATION FROM SRN LA
INTO TX...AHEAD OF THE NEXT APPROACHING SRN STREAM SHORT WAVE
TROUGH. SHEAR AND INSTABILITY IN EITHER OF THESE SCENARIOS WOULD
SUPPORT A FEW SUPERCELLS OR SHORT LINE SEGMENTS WITH WIND AND HAIL
LIKELY. IF BOTH SCENARIOS BECOME INCREASINGLY LIKELY...HIGHER SEVERE
PROBABILITIES WILL BE REQUIRED WITHIN THE SLGT RISK AREA.

..CARBIN/CROSBIE.. 03/19/2005

...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.