[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 280612
SWODY2
SPC AC 280611

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0111 AM CDT THU APR 28 2005

VALID 291200Z - 301200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 SSE
GPT ESF SHV 40 E PRX PGO FSM HRO SLO IND DAY CMH UNI HTS TYS LGC
PFN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 E ECG RWI RDU CLT
AGS 45 W CTY ...CONT... 25 SSW BPT 60 SSW TYR 20 WNW PRX MKO TUL PNC
45 NE GAG DDC HLC HSI LNK OTM MLI CGX BEH AZO JXN DTW ERI BFD IPT
ABE 35 SE NEL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM SVE 35 NE RBL MHS MFR
EUG SLE PDX YKM ALW SUN BYI 60 NNW ENV EKO LOL SVE.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 W RTN 40 SW COS 30
NNW COS LIC LAA DHT TCC LVS 25 W RTN.

...THERE IS A SLGT RISK OF SVR TSTMS ARKLATEX REGION TO LOWER/MID OH
VALLEY AND CENTRAL GULF COAST...

...SYNOPSIS...
PROGRESSIVE SRN STREAM PATTERN IS FCST TO PREVAIL THROUGH PERIOD. 
MID/UPPER LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY
APPROXIMATELY 20 NM OFFSHORE MRY -- IS FCST TO MOVE INLAND DAY-1 AND
ACROSS GREAT BASIN.  THIS FEATURE SHOULD ACCELERATE EWD ACROSS SRN
ROCKIES AND SRN HIGH PLAINS AROUND BEGINNING OF PERIOD...AS NRN
STREAM TROUGH NOW OVER ALBERTA DIGS SEWD.  SRN TROUGH THEN WILL
ACCELERATE EWD ACROSS OK AND OZARKS THEN NEWD OVER OH
VALLEY...REACHING ERN INDIANA/WRN OH AREA BY 30/12Z. ASSOCIATED SFC
CYCLONE IS EXPECTED TO MOVE FROM OK NEWD ACROSS OZARKS AND LOWER OH
VALLEY DURING DAY3...DEEPENING CONSIDERABLY WHILE ATTACHED COLD
FRONT SWEEPS SEWD OVER SRN PLAINS AND LOWER MS VALLEY. WARM FRONT
SHOULD LIFT NWD ACROSS TN VALLEY REGION AND NERN AR/MO BOOTHEEL
AREAS...AHEAD OF SFC LOW.

...LOWER MS VALLEY REGION TO CENTRAL/ERN GULF COAST...
POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT REMAINS POSSIBLE --
PARTICULARLY ALONG AND JUST RIGHTWARD OF SFC CYCLONE TRACK...WHERE
SHEAR/INSTABILITY COMBINATIONS SHOULD BE MAXIMIZED.

BECAUSE OF INTENSE DEEP-LAYER WIND FIELDS...STORMS WILL BE FAST
MOVING AND ANY SUSTAINED/DISCRETE SUPERCELLS THAT DO DEVELOP COULD
PRODUCE LONG TRACK TORNADOES.  MAIN FACTOR PRECLUDING OUTLOOK
UPGRADE ATTM REMAINS UNCERTAINTIES REGARDING CONVECTIVE MODE --
PARTICULARLY...DURATION OF ANY THREAT FOR DISCRETE SUPERCELLS IN
THAT ZONE OF ENHANCED SHEAR NEAR SFC CYCLONE...AND POTENTIAL FOR
QUICK TRANSITION TO LINEAR/CLUSTERED CONVECTION.  LATEST DRT/MAF
RAOBS INDICATE SOME RELATIVELY STABLE LAYERS IN MIDLEVELS 
CORRESPONDING TO INCOMPLETE DEVELOPMENT OF ELEVATED MIXED LAYER. 
THIS REGIME ALOFT -- TRANSLATED NEWD -- INDICATES POTENTIAL FOR
RELATIVELY UNCAPPED AIR MASS THAT WOULD SUPPORT RAPID DEVELOPMENT OF
LINEAR CONVECTIVE SYSTEM.

VIGOROUS LOW LEVEL WAA REGIME THROUGH DAY1 AND EARLY DAY2 WILL
COMBINE WITH SFC HEATING TO DESTABILIZE WRM SECTOR ACROSS ERN
PORTION OF OUTLOOK AREA DURING DAY...AMIDST SFC DEW POINTS
MOISTENING INTO 60S F. THIS LEADS TO AFTERNOON MLCAPES 1500-2000
J/KG IN MODIFIED ETA FCST SOUNDINGS.  VERTICAL SHEAR WILL BE
FAVORABLE FOR BOTH SUPERCELLS AND DAMAGING BOW ECHOES...WITH 70-80
KT MIDLEVEL FLOWS CONTRIBUTING TO SIMILAR VALUES OF AFTERNOON 0-6 KM
LAYER SHEARS.  NARROW AREA OF BACKED SFC FLOW INVOF WARM FRONT
MAY PRODUCE 0-6 KM AND EFFECTIVE LAYER SHEARS AROUND 90 KT...AND 0-1
KM SRH EXCEEDING 200 J/KG.

TSTMS ARE EXPECTED TO BECOME MORE NUMEROUS THROUGHOUT LATE AFTERNOON
INTO EVENING...PERHAPS BACKBUILDING AS FAR AS GULF COASTAL REGION OF
MS/AL/FL PANHANDLE BY END OF PERIOD...WITH DAMAGING WIND BEING MAIN
THREAT BUT SUPERCELLS/TORNADOES STILL POSSIBLE.

...OH VALLEY REGION...
AS SFC LOW CONTINUES TO DEEPEN AND LIFT NEWD...VIGOROUS ISALLOBARIC
FORCING WILL MAINTAIN/EXPAND BOTH BACKING OF SFC FLOW AND LOW LEVEL
CONVERGENCE.  THIS WILL CONTRIBUTE TO POTENTIAL FOR STRONGLY
FORCED...POSSIBLY LOW-TOPPED ARC OF CONVECTION MOVING RAPIDLY NEWD
ACROSS REGION OVERNIGHT...WITH POTENTIAL FOR WIND DAMAGE.  MAIN
LIMITING FACTOR WILL BE LACK OF SIGNIFICANT SFC-BASED
BUOYANCY...RELATED TO
1. WITH NEWD EXTENT...PROGRESSIVELY MORE INFLOW TRAJECTORIES
ORIGINATING FROM RELATIVELY LOW THETAE AIR MASS OF CONTINENTAL
ANTICYCLONE TO THE E/SE...AND
2. LIKELY WEAKENING TREND IN INSTABILITY WITH TIME...AS DIABATIC
COOLING COUNTERACTS SFC WAA.

..EDWARDS.. 04/28/2005

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
WILL PROVIDE DETAILS ON THE TRANSITION.