[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 150534
SWODY1
SPC AC 150532

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1232 AM CDT SUN AUG 15 2004

VALID 151200Z - 161200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM RRT 40
ENE TVF 45 E BJI 50 E BRD 10 NE MSP SPW SUX MHN 10 SSW CDR RAP MBG
BIS 10 SE DIK 10 SSE ISN 75 NE ISN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 55 ENE ELO 45 W RHI
15 E LSE 10 SW P35 30 ENE CNU 15 NNE MKO 15 E MLC 10 SW DAL 30 SSW
SEP 20 NNE JCT 30 NW DRT ...CONT... 15 WSW CZZ 25 ESE EDW 55 N BFL
25 WSW TVL 25 NNW SVE 30 SSE LMT 20 SE MFR 40 NNW MFR 10 S PDX 45 E
AST 25 S UIL ...CONT... 45 N FCA 3DU 40 NNE WEY 35 W WRL 35 ESE RIW
40 WSW RWL 40 S RWL 40 NW LAR 20 NNW DGW 45 NE 81V 50 NNE REJ 45 E
GDV 25 WNW SDY 60 N OLF.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 SE TLH 25 E ABY 40
E LGC 35 N GAD 60 N CSV 30 NW HTS 25 ENE CMH 40 N CLE ...CONT... 15
W MSS 25 S BTV 20 SSW PWM.

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTN/EVE ACROSS PARTS OF
THE NRN PLAINS....

TREND TOWARD SLIGHTLY LESS AMPLIFIED UPPER FLOW PATTERN ACROSS THE
U.S. WILL CONTINUE THROUGH THIS FORECAST PERIOD...BUT MODELS SUGGEST
BROAD TROUGHING WILL PERSIST OVER THE CENTRAL/EASTERN STATES...WITH
WEAK RIDGE IN THE WEST.  REMNANTS OF CHARLEY WILL ACCELERATE EAST
NORTHEASTWARD FROM CAPE COD INTO THE CANADIAN MARITIMES...ON
NORTHWESTERN PERIPHERY OF ATLANTIC RIDGE.  MEANWHILE...CLOSED LOW
WILL REMAIN QUASI-STATIONARY OVER THE NORTHEAST PACIFIC...TO THE
SOUTH OF BLOCKING RIDGE OVER ALASKA.

...CENTRAL STATES...
EMBEDDED WITHIN LARGE-SCALE UPPER FLOW REGIME...A VIGOROUS SHORT
WAVE TROUGH IS EVIDENT IN LATEST WATER VAPOR IMAGERY DIGGING ACROSS
SASKATCHEWAN/MANITOBA. MODELS ARE SIMILAR IN FORECASTING THIS
SYSTEM SOUTHEASTWARD INTO THE DAKOTAS BY THE PEAK HEATING HOURS
TODAY...THEN EASTWARD INTO THE UPPER MISSISSIPPI VALLEY BY EARLY
MONDAY.

MID-LEVEL COLD POOL /500 MB TEMPS TO AROUND -15C/ AND 40 KT CYCLONIC
MID-LEVEL JET ASSOCIATED WITH UPPER SYSTEM WILL CONTRIBUTE TO LIFT
AND DESTABILIZATION SUFFICIENT FOR CONVECTIVE DEVELOPMENT.  THOUGH
ENVIRONMENT IS CURRENTLY RATHER DRY...AT LEAST NARROW TONGUE OF MID
50S DEW POINTS IS EXPECTED TO ADVECT NORTHWARD OUT OF THE CENTRAL
HIGH PLAINS...AHEAD OF PRE-FRONTAL SURFACE TROUGH...INTO
CENTRAL/EASTERN SOUTH DAKOTA BY LATE THIS AFTERNOON.  IN CONJUNCTION
WITH MID-LEVEL FORCING AND STRONG DAYTIME HEATING...DEEP MIXED
BOUNDARY LAYER WITH CAPE IN EXCESS OF 1000 J/KG LIKELY WILL DEVELOP.


ISOLATED VIGOROUS CONVECTIVE DEVELOPMENT IS POSSIBLE AS EARLY AS MID
DAY IN CLOSE PROXIMITY TO CYCLONIC VORTICITY CENTER/CORE OF
MID-LEVEL COLD POOL ACROSS PARTS OF NORTHERN/CENTRAL NORTH DAKOTA. 
HOWEVER...PRIMARY THUNDERSTORM ACTIVITY AND ASSOCIATED SEVERE THREAT
WILL LIKELY INITIATE AFTER 15/21Z...AS INHIBITION WEAKENS EAST OF
DEVELOPING SURFACE LOW...EAST OF PIERRE SD.  LOW-LEVEL WARM
ADVECTION IS PROGGED TO STRENGTH ACROSS MUCH OF EASTERN SOUTH DAKOTA
INTO THE EARLY EVENING HOURS...AND WILL CONTRIBUTE TO FAVORABLE
ENVIRONMENT FOR SUPERCELLS.  LARGE HAIL WILL BE PRIMARY THREAT...AS
ACTIVITY INCREASES AND SPREADS EASTWARD TOWARD THE UPPER MISSISSIPPI
VALLEY.  GIVEN LIMITED MOISTURE...SEVERE THREAT LIKELY WILL DIMINISH
BY LATE EVENING...AS MAGNITUDE OF INSTABILITY WEAKENS WITH LOSS OF
HEATING.

...WESTERN STATES...
MOISTURE SOUTH AND WEST OF UPPER RIDGE WILL AGAIN CONTRIBUTE TO
ENVIRONMENT SUPPORTIVE OF NUMEROUS THUNDERSTORMS ACROSS THE
INTERMOUNTAIN WEST AND SOUTHERN ROCKIES.  WIDESPREAD CONVECTION MAY
LIMIT MAGNITUDE OF DESTABILIZATION AND ASSOCIATED SEVERE THREAT. 
HOWEVER...IN WAKE OF A MID-LEVEL SHEAR AXIS EMBEDDED WITHIN
RIDGE...STRONG HEATING APPEARS LIKELY IN THE LEE OF THE OREGON
CASCADES.  MODELS SUGGEST DEVELOPMENT OF DEEP MIXED BOUNDARY LAYER
WITH CAPE IN EXCESS OF 1000 J/KG.  THIS WILL BE SUFFICIENT FOR
SCATTERED VIGOROUS CONVECTIVE DEVELOPMENT...DESPITE WEAK FLOW/SHEAR
REGIME.  ISOLATED STRONGER STORMS...PERHAPS AIDED BY WEAKLY DIFLUENT
UPPER FLOW...MAY PRODUCE SOME HAIL/STRONG DOWNBURSTS.

...EASTERN STATES...
MOIST UNSTABLE ENVIRONMENT NEAR SURFACE FRONT ACROSS THE EASTERN
CAROLINAS WILL BE SUPPORTIVE OF THUNDERSTORM ACTIVITY...WITH
ADDITIONAL STORMS LIKELY ACROSS THE FLORIDA PENINSULA...AIDED BY
FORCING ALONG SEA BREEZES.  WEAKLY SHEARED TROPICAL THERMODYNAMIC
ENVIRONMENT SEEMS TO MARGINALIZE SEVERE THREAT...THOUGH FAIRLY LARGE
CAPE AND HIGH PRECIPITABLE WATER WILL PROVE FAVORABLE FOR HEAVY
DOWNPOURS.

SOMEWHAT BETTER CONVECTIVE INSTABILITY APPEARS POSSIBLE THIS
AFTERNOON ALONG THE WEST SLOPES OF THE SOUTHERN APPALACHIANS...AS
SHORT WAVE TROUGH LIFTS NORTHEASTWARD OUT OF THE LOWER MISSISSIPPI
VALLEY.  CAPE LIKELY WILL REMAIN AT OR BELOW 1000 J/KG...BUT
MODERATE SOUTHWESTERLY MID-LEVEL FLOW ACROSS THE SOUTHERN
APPALACHIANS WILL ENHANCE SHEAR...AND MAY SUPPORT AN ISOLATED STRONG
STORM OR TWO WITH HAIL/GUSTY WINDS.

..KERR/JEWELL.. 08/15/2004

...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.