Wednesday, August 1, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 010538
SWODY1
SPC AC 010536

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT WED AUG 01 2007

VALID 011200Z - 021200Z

..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
PARTS OF NRN AND CNTRL MN...

..SYNOPSIS...

STRONG SHORT WAVE TROUGH CURRENTLY MOVING THROUGH AB/SK IS FORECAST
TO UNDERGO FURTHER AMPLIFICATION AS IT CONTINUES ESEWD THROUGH MB
AND ONTARIO. ACCOMPANYING 50-60 KT MID-LEVEL JET STREAK WILL REMAIN
N OF THE INTERNATIONAL BORDER...THOUGH SRN FRINGE OF STRONGER HEIGHT
FALLS WILL SPREAD EWD THROUGH THE UPPER MS VALLEY INTO UPPER GREAT
LAKES. IN THE LOW LEVELS...COLD FRONT ATTENDANT TO THIS SYSTEM WILL
CONCURRENTLY SHIFT EWD THROUGH THE UPPER MS VALLEY...LIKELY
EXTENDING FROM THE MN ARROWHEAD SWWD THROUGH SERN SD...N-CNTRL NEB
INTO NERN CO BY EARLY THIS EVENING.

..NRN/CNTRL MN...

CURRENT SURFACE OBSERVATIONS AND GOES SOUNDER PW IMAGERY SHOW AN
AXIS OF RICHER BOUNDARY LAYER MOISTURE /DEWPOINTS OF 65-70 F/ WITHIN
PRE-FRONTAL AIR MASS OVER THE ERN DAKOTAS. THIS MOIST AXIS WILL
GRADUALLY SHIFT EWD TODAY /MAINTAINED BY A SWLY 20-25 KT LLJ/ AND
COMBINE WITH DAYTIME HEATING TO SUPPORT A MODERATELY
UNSTABLE...PRE-FRONTAL AIR MASS WITH MLCAPES OF 1500-2500 J/KG.

SOME REMNANTS OF SMALL MCS CURRENTLY OVER NERN ND MAY BE IN PROGRESS
LATER THIS MORNING OVER NWRN/N-CNTRL MN. ANY ONGOING STORMS
ASSOCIATED WITH THIS SYSTEM SHOULD REINTENSIFY BY AFTERNOON WITH
ADDITIONAL STORM DEVELOPMENT LIKELY ALONG FRONT AS AIR MASS BECOMES
INCREASINGLY UNSTABLE. AS MENTIONED ABOVE...STRONGER DEEP-LAYER
WIND FIELDS WILL REMAIN N OF THE BORDER...THOUGH FORECAST SOUNDINGS
INDICATE EFFECTIVE BULK SHEARS APPROACHING 30 KT OVER NRN MN. THIS
MODEST FLOW IN CONJUNCTION WITH LOCALLY STRONGER HEIGHT FALLS
INDICATE THE POTENTIAL FOR SOME STORM ORGANIZATION WITH A THREAT OF
DAMAGING WINDS AND HAIL THROUGH THE EVENING HOURS.

..SRN MN SWWD THROUGH THE MID MO VALLEY INTO CNTRL HIGH PLAINS...

DIABATIC HEATING COUPLED WITH DEWPOINTS IN THE MID 60S TO LOWER 70S
WILL RESULT IN THE DEVELOPMENT OF MODERATE TO POTENTIALLY STRONG
INSTABILITY ACROSS PRE-FRONTAL WARM SECTOR WITH MLCAPES APPROACHING
2000-3000 J/KG. TSTMS ARE EXPECTED TO DEVELOP PROGRESSIVELY SWWD
ALONG THE FRONT THROUGH THE AFTERNOON HOURS FROM W-CNTRL/SWRN MN
THROUGH ERN SD INTO NRN NEB AND EVENTUALLY NERN CO/SERN WY.

LATEST MODEL GUIDANCE INDICATES MODEST /40-45 KT/ HIGH-LEVEL FLOW
ACROSS THE REGION. HOWEVER...LOW AND MID-TROPOSPHERIC WIND FIELDS
WILL REMAIN QUITE WEAK WHICH SHOULD TEND TO LIMIT A MORE ORGANIZED
SEVERE THREAT. STILL...SOME POTENTIAL WILL EXIST FOR
STRONG/MARGINALLY SEVERE PULSE OR MULTICELL STORMS CAPABLE OF
ISOLATED HAIL/LOCALLY STRONG WIND GUSTS.

.MEAD/GRAMS.. 08/01/2007

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write chris@lib.siu.edu.

No comments: