[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 201258
SWODY1
SPC AC 201256

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0756 AM CDT TUE JUL 20 2004

VALID 201300Z - 211200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 45 NNW
ELO 50 SSE DLH 10 NW MSN 35 WNW CGX 30 ENE BMI 35 E UIN 20 NW IRK 30
NNW OMA 40 WNW YKN 50 E MBG 70 N DVL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 S CTY 55 S AGS 30
NNW SOP 20 WNW ROA 30 SE JKL 45 NNW CSV 35 WSW HOP 35 N TXK 15 SE
MLC 40 SSW OJC 20 NNE EMP 25 WNW HUT 40 W P28 50 E LBB P07
...CONT... 15 SE FHU 45 WNW SAD 15 WSW FLG 30 W P38 65 N BIH 35 SSE
NFL 20 SE WMC 85 WNW OWY 55 W BKE 25 ESE GEG 50 NE 63S.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN PLAINS
/ UPPER MS VALLEY REGION...

...SYNOPSIS...
MID-LEVEL FLOW PATTERN FORECAST TO DEAMPLIFY WITH TIME THROUGH THE
DAY 1 PERIOD AS WRN U.S. TROUGH WEAKENS AND ERN U.S. TROUGH SHIFTS
SLOWLY EWD.  MEANWHILE...RIDGE CENTERED OVER THE SRN ROCKIES IS
FORECAST TO EXPAND WWD INTO CA AND EWD INTO THE MID MS / LOWER OH
VALLEYS TO THE N OF WEAK / DEVELOPING LOW OVER THE WRN GULF.

MEANWHILE...SEVERAL SHORT-WAVE FEATURES WILL MOVE EWD ACROSS THE NRN
ROCKIES / NRN PLAINS AND INTO THE GREAT LAKES REGION WITHIN BELT OF 
MODERATE / INCREASINGLY ZONAL WLY FLOW.

AT THE SURFACE...WEAK LOW IS INDICATED ACROSS S CENTRAL SD
ATTM...WITH BOUNDARY EXTENDING EWD ACROSS THE MID MO VALLEY INTO THE
UPPER LAKES.  MEANWHILE...A TROUGH EXTENDS NWWD FROM THIS LOW INTO A
SECOND / SOMEWHAT DEEPER LOW OVER SRN SASKATCHEWAN.  WITH
TIME...THIS COMPLEX TROUGH OF LOW PRESSURE IS EXPECTED TO SHIFT EWD
ACROSS SRN CANADA / THE NRN AND CENTRAL PLAINS...WITH A MORE
WELL-DEFINED COLD FRONT TO EVOLVE / MOVE SEWD ACROSS THE NRN AND
CENTRAL PLAINS LATER IN THE PERIOD.  MAIN AREA OF SEVERE RISK THIS
PERIOD IS FORECAST FROM ERN PORTIONS OF THE NRN PLAINS EWD INTO THE
UPPER MS VALLEY REGION AHEAD OF AFOREMENTIONED LOWS / FRONTS.

...N CENTRAL CONUS...
AS WEAK BOUNDARY ACROSS NRN KS / SRN NEB RETREATS NWD AND
DUAL-CENTERED LOW SHIFTS EWD ACROSS SRN CANADA / THE NRN PLAINS THIS
AFTERNOON...MOIST AIRMASS ACROSS THE RED RIVER / MID MO / UPPER MS
VALLEYS SHOULD BECOME MARGINALLY TO MODERATELY UNSTABLE.  WEAK
STORMS NOW ONGOING ACROSS PARTS OF THE DAKOTAS MAY LINGER INTO THE
AFTERNOON...WITH SCATTERED STORMS EXPECTED TO DEVELOP / INTENSIFY
THROUGH THE AFTERNOON -- MAINLY FROM THE ERN DAKOTAS  / NEB EWD INTO
MN / IA.  

ALTHOUGH GENERALLY WEAK LOW-LEVEL FEATURES MAKE A PRECISE FORECAST
OF LOCATIONS OF GREATER SEVERE THREAT DIFFICULT ATTM...IT APPEARS
ATTM THAT GREATEST THREAT SHOULD EXIST GENERALLY ALONG NRN / ERN
FRINGES OF WEAK LOW FORECAST BY THE ETA ACROSS ERN PORTIONS OF NEB /
SD DURING THE AFTERNOON / EARLY EVENING.  ASSOCIATED SLY / SELY
LOW-LEVEL FLOW ACROSS THIS REGION BENEATH 25 TO 30 KT WLY FLOW ALOFT
SUGGESTS DEEP-LAYER SHEAR FAVORABLE FOR SEVERE / SUPERCELL STORMS. 
IN ADDITION TO THREAT FOR LOCALLY DAMAGING WINDS / HAIL...AN
ISOLATED TORNADO OR TWO MAY ALSO OCCUR -- PARTICULARLY NEAR WEAK
WARM FRONT ASSOCIATED WITH NEB / SD LOW.

AS SWLY LOW-LEVEL JET DEVELOPS THIS EVENING / OVERNIGHT...STORMS
SHOULD CONTINUE AND MAY SPREAD EWD ACROSS THE UPPER MS RIVER VALLEY.


SOME SEVERE THREAT MAY EXTEND EWD ACROSS THE SRN GREAT LAKES / OH
VALLEY REGION THIS AFTERNOON / EVENING WHERE MOIST /
MODERATELY-UNSTABLE AIRMASS SHOULD EVOLVE WITHIN ENVIRONMENT OF
MODERATE NWLY MID-LEVEL FLOW BEHIND RETREATING TROUGH. ALTHOUGH
SOME THREAT FOR DAMAGING WINDS / HAIL WILL EXIST WITH THE ANY
STRONGER STORM...THREAT IN THIS REGION SHOULD REMAIN ISOLATED.

...NRN ROCKIES...
MID-LEVEL TROUGH NOW MOVING EWD ACROSS ID / NV -- AND ASSOCIATED
MID-LEVEL JET STREAK -- MAY CONTRIBUTE TO ISOLATED SEVERE THREAT AS
IT SPREADS EWD ACROSS THE NRN ROCKIES. ALTHOUGH INSTABILITY IS
FORECAST TO REMAIN MARGINAL...POCKETS OF MEAN-LAYER CAPE APPROACHING
1000 J/KG MAY DEVELOP DURING THE AFTERNOON FROM SERN ID ENEWD ACROSS
NWRN WY / SRN MT.  THIS COMBINED WITH 35 TO 40 KT WLY FLOW AT MID
LEVELS MAY SUPPORT A FEW MORE INTENSE / SEVERE STORMS CAPABLE OF
PRODUCING LOCALLY DAMAGING WINDS / HAIL.  LIMITED INSTABILITY AND
LACK OF LARGE-SCALE CONVERGENCE SUGGEST THAT THREAT SHOULD REMAIN
ISOLATED.

..GOSS.. 07/20/2004

...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.