SWODY1
SPC AC 221624
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1124 AM CDT MON SEP 22 2008
VALID 221630Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE NORTHERN
AND CENTRAL PLAINS...
...NORTHERN PLAINS...
A LARGE UPPER TROUGH HAS BECOME ESTABLISHED OVER THE NORTHWEST
QUARTER OF THE UNITED STATES TODAY...WITH A SERIES OF SHORTWAVE
TROUGHS TRACKING FROM THE GREAT BASIN INTO THE NORTHERN PLAINS. THE
PRIMARY TROUGH IS CURRENTLY SHOWN ON WATER VAPOR IMAGERY OVER PARTS
OF WESTERN WY-NORTHERN UT. THIS TROUGH AND ITS ASSOCIATED LARGE
SCALE FORCING WILL OVERSPREAD THE ROCKIES AND INTO THE NORTHERN HIGH
PLAINS BY EARLY EVENING. MORNING SOUNDINGS SHOWED A SUBSTANTIAL
CAPPING INVERSION THAT WILL SUPPRESS SURFACE-BASED CONVECTION UNTIL
LATE IN THE DAY. HOWEVER...SOUTHERLY LOW LEVEL WINDS WILL MAINTAIN
DEWPOINTS IN THE 50S WITH POCKETS OF MLCAPE AROUND 1000 J/KG
EXPECTED BY PEAK HEATING.
PRESENT INDICATIONS ARE THAT ELEVATED CONVECTION MAY EVENTUALLY
BECOME SURFACE-BASED AND INTENSIFY NEAR SURFACE COLD FRONT OVER
SOUTHERN ND/NORTHERN SD BY MID/LATE AFTERNOON. ACTIVITY WILL THEN
LIKELY DEVELOP SOUTHWESTWARD ALONG THE FRONT TOWARD THE BLACK HILLS
AS UPPER TROUGH APPROACHES. SEVERE THREAT MAY PERSIST THROUGH MUCH
OF THE EVENING AS STORMS SPREAD EASTWARD ACROSS RISK AREA.
SUPERCELL STORMS STRUCTURES ARE EXPECTED WITH A RISK OF LARGE HAIL
AND DAMAGING WINDS IN STRONGER CORES. ISOLATED TORNADOES ARE
POSSIBLE...ALTHOUGH LIMITED LOW LEVEL MOISTURE IS EXPECTED TO LIMIT
OVERALL TORNADO RISK.
..HART/JEWELL.. 09/22/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment