Wednesday, July 7, 2010

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 071948
SWODY1
SPC AC 071946

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0246 PM CDT WED JUL 07 2010

VALID 072000Z - 081200Z

...NO SVR TSTM AREAS FORECAST...

FEW CHANGES MADE TO PREVIOUS OUTLOOK. PRIMARY REGIONS OF HIGH
MOISTURE CONTENT AND INSTABILITY REMAIN CHARACTERIZED BY MARGINAL
VERTICAL SHEAR AT BEST. WIDELY SCATTERED CLUSTERS OF STORMS FROM
IA/NRN IL INTO WI AND LOWER MI ARE OCCURRING AHEAD OF A COLD FRONT
IN ADVANCE OF UPPER TROUGH MOVING ACROSS THE NRN PLAINS. ISOLATED
STRONG WIND GUSTS MAY BE POSSIBLE WITH STRONGER CELLS. FARTHER
SOUTHWEST ADDITIONAL STRONG STORMS HAVE DEVELOPED FROM PARTS OF OK
INTO WRN TX WHERE ISOLATED MICROBURSTS OR MARGINALLY SEVERE HAIL MAY
OCCUR. FINALLY...STRONG STORMS CONTINUE TO DEVELOP OVER THE HIGHER
TERRAIN FROM CENTRAL CO SWD INTO PARTS OF NM. OVERALL SEVERE
THREATS APPEAR LIMITED BY WEAK LAPSE RATES AND WEAK WINDS/VERTICAL
SHEAR.

..WEISS.. 07/07/2010

.PREV DISCUSSION... /ISSUED 1113 AM CDT WED JUL 07 2010/

...SYNOPSIS...
SRN PORTION OF LARGE TROUGH OVER CENTRAL CANADA WILL TRANSLATE EWD
ACROSS NRN PLAINS/UPPER MS VALLEY THIS FORECAST PERIOD. EFFECTIVE
COLD FRONT EXTENDS FROM CENTRAL MN SWWD TO NEAR OMA-DDC-DHT LINE
THIS AM. A BROAD STREAM OF TROPICAL AIR CONTINUES TO FEED NWD THRU
THE PLAINS INTO THE WESTERN GREAT LAKES IN ADVANCE OF THE FRONT.

...CENTRAL PLAINS INTO WESTERN GREAT LAKES REGION...
THE AIR MASS ALONG AND SOUTH OF THE FRONT WILL BE VERY MOIST WITH
DEWPOINTS IN THE 70S AND SCATTERED SHOWERS AND THUNDERSTORMS
EXPECTED THROUGH THE PERIOD. DESPITE AMPLE MOISTURE AND AFTERNOON
MLCAPE VALUES OVER 1500 J/KG...FORECAST SOUNDINGS SHOW POOR MID
LEVEL LAPSE RATES AND WEAK LOW LEVEL FLOW. MARGINAL EFFECTIVE SHEAR
VALUES WILL ALSO LIMIT CONVECTIVE ORGANIZATION.
NEVERTHELESS...ISOLATED STRONG MULTICELL STORMS WILL BE POSSIBLE
ACROSS A LARGE PORTION OF THE CENTRAL US TODAY WITH LOCALLY
GUSTY/DAMAGING WINDS THE MAIN THREAT.

...CENTRAL HIGH PLAINS...
PLUME OF STEEPER LAPSE RATES WILL REMAIN ACROSS CO AND
WESTERN KS THIS AFTERNOON ATOP A MOIST POST-FRONTAL AIR MASS CENTRAL
HIGH PLAINS. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER
THE HIGHER TERRAIN OF CENTRAL CO AND SPREAD EASTWARD THROUGH THE
EVENING. VERTICAL SHEAR IS MARGINAL FOR ORGANIZED STORMS.
HOWEVER...STRONGER STORMS COULD PRODUCE HAIL AND GUSTY/DAMAGING
WINDS AS THEY ARE ABLE TO TAP INTO THE LOW LEVEL MOISTURE ACROSS THE
CO PLAINS.

...EAST TX...
LATEST MODELS CONTINUE TO MOVE LARGER-SCALE TROPICAL CIRCULATION
TOWARD SOUTH/SOUTHEAST TX LATER TODAY. RELATIVELY STRONG LOW/MID
LEVEL WINDS ON THE EAST SIDE OF THIS SYSTEM OVER THE NRN GULF WILL
SPREAD INLAND AND ENHANCE VERTICAL SHEAR AND POTENTIALLY LEAD TO A
LOCALIZED BRIEF TORNADO THREAT SERN TX BY EARLY TONIGHT.

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