[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 151734
SWODY2
SPC AC 151733

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1233 PM CDT SUN AUG 15 2004

VALID 161200Z - 171200Z

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 NNE FCA 15 NNE 4BQ
25 S RAP 50 NNE BUB 20 S FSD 45 ESE RRT ...CONT... 30 S OSC 20 N AZO
10 SSW POF 40 NNW BGS 35 SW P07 ...CONT... 25 NNW YUM 55 WSW EED 15
NW DRA 40 SE BIH 40 WNW BIH 20 NNW NFL 40 ESE MHS 25 NNE MFR 30 ENE
BLI.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 WNW PFN 20 NNW ABY
15 W RMG 50 NW HSS 15 SW SSU 20 NNE ROC 10 W MSS 15 NE EFK 15 S PSM.

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
STRONG MID-LEVEL LOW / VORT MAX -- NOW MOVING SSEWD TOWARD ND -- IS
FORECAST TO BE SITUATED ACROSS THE UPPER MS VALLEY REGION AT THE
START OF THE PERIOD.  ASSOCIATED SURFACE FRONT EXTENDING FROM MN
SWWD INTO NERN CO IS FORECAST TO MOVE SLOWLY SEWD THROUGH THE PERIOD
AS MID-LEVEL LOW WEAKENS / CROSSES THE UPPER GREAT LAKES REGION
THROUGH 17/12Z.  BY THE END OF THE PERIOD...FRONT SHOULD EXTEND FROM
NRN LK MI WSWWD ACROSS IA INTO SERN NEB / NRN KS / ERN CO.

OTHERWISE...LARGE-SCALE MID-LEVEL PATTERN WILL CHANGE LITTLE...WITH
A RIDGE OVER THE ROCKIES AND A BROAD / LOW-AMPLITUDE TROUGH OVER THE
CENTRAL AND ERN CONUS.

...UPPER MS VALLEY SWWD ACROSS THE MIDDLE MO VALLEY...
MID-LEVEL VORT MAX AND ASSOCIATED 30 TO 40 KT MID-LEVEL JET STREAK
MOVING SEWD / ESEWD ACROSS THE NRN PLAINS / UPPER LAKES WILL BE A
FOCUS FOR A LOW-END SEVERE STORM THREAT THIS PERIOD.

CLUSTER OF PRIMARILY ELEVATED THUNDERSTORMS SHOULD BE ONGOING FROM
IA NEWD INTO PARTS OF MN / WI AHEAD OF THIS FEATURE / WITHIN ZONE OF
LOW-LEVEL WARM ADVECTION ASSOCIATED WITH LOW-LEVEL JET.  THIS
CONVECTION SHOULD PERSIST THROUGH THE DAY AS UPPER FEATURE SHIFTS
ESEWD. HOWEVER...MARGINAL INSTABILITY ANTICIPATED THROUGH THE DAY
DOWNSTREAM OF THIS CLUSTER SUGGESTS ONLY A LOW-PROBABILITY THREAT
FOR MARGINAL HAIL WITH A FEW OF THE STRONGER STORMS.

BEHIND THIS CONVECTIVE CLUSTER / ALONG SURFACE BOUNDARY...ETA
SUGGESTS THAT AIRMASS MAY DESTABILIZE WITH 1000 TO 2000 J/KG
MEAN-LAYER CAPE INDICATED BY AFTERNOON.  HOWEVER...ETA FORECAST
SOUNDINGS ACROSS THIS REGION REVEAL ARTIFICIAL STEEPENING OF
LOW-LEVEL LAPSE RATES BY ACTIVE SHALLOW CONVECTIVE PARAMETERIZATION.
 IT APPEARS THAT MORE LIKELY SCENARIO WILL BE THAT ANY
DESTABILIZATION OF CONVECTIVELY-CONTAMINATED AIRMASS SHOULD QUICKLY
RESULT IN NEW CONVECTIVE DEVELOPMENT -- AND THUS LITTLE POTENTIAL
FOR THE DEVELOPMENT OF APPRECIABLE INSTABILITY.  ALTHOUGH DEEP-LAYER
WIND FIELD WOULD SUPPORT STORM ORGANIZATION / SEVERE THREAT...WILL
MAINTAIN ONLY LOW-PROBABILITY SEVERE THREAT GIVEN FORECAST FOR
PERSISTENT CONVECTION AND ASSOCIATED LACK OF POTENTIAL FOR
SIGNIFICANT AIRMASS DESTABILIZATION.

SOMEWHAT GREATER THREAT MAY EXIST ALONG SRN FRINGES OF OVERNIGHT
CONVECTIVE CLUSTER WHERE AIRMASS COULD POTENTIALLY BECOME SOMEWHAT
MORE UNSTABLE. HOWEVER...SHEAR DECREASES WITH SWD EXTENT AND THUS
ATTM EXPECT SEVERE THREAT TO REMAIN BELOW SLIGHT RISK THRESHOLDS
ACROSS THE ENTIRE REGION.

...ERN WY / SWRN SD NERN CO EWD INTO NEB...
UPSLOPE FLOW RESULTING FROM SELY LOW-LEVEL FLOW JUST N OF SAGGING
SURFACE BOUNDARY MAY PROVIDE SUFFICIENT UVV FOR STORM INITIATION
OVER ERN WY AND PERHAPS NERN CO...WHERE AIRMASS SHOULD BECOME
MARGINALLY UNSTABLE BY AFTERNOON.  ISOLATED STORM DEVELOPMENT MAY
ALSO OCCUR EWD ACROSS NEB WITHIN WEAK LOW-LEVEL CONVERGENCE ALONG
SURFACE BOUNDARY -- TO THE SW OF ONGOING CONVECTION OVER IA / MN /
WI -- WHERE SOMEWHAT GREATER INSTABILITY SHOULD DEVELOP.

FORECAST 20 TO 25 KT MID-LEVEL FLOW SHOULD PROVIDE SUFFICIENT SHEAR
FOR WEAK UPDRAFT ORGANIZATION AND ASSOCIATED THREAT FOR LOCALLY
DAMAGING WINDS / MARGINAL HAIL.  ALTHOUGH SOMEWHAT GREATER
DEEP-LAYER SHEAR SHOULD EXIST OVER THE HIGH PLAINS DUE TO SELY
LOW-LEVEL FLOW...WEAKER INSTABILITY ACROSS THIS REGION SHOULD OFFSET
MORE FAVORABLE WIND FIELD.  OVERALL RESULT SHOULD BE A GENERALLY
LOW-PROBABILITY THREAT ACROSS THE ENTIRE AREA.

..GOSS.. 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.