SWODY1
SPC AC 290057
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0757 PM CDT TUE APR 28 2009
VALID 290100Z - 291200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SRN HIGH PLAINS...
...SRN HIGH PLAINS...
EARLY EVENING SURFACE ANALYSIS INDICATED PRIMARY SYNOPTIC BOUNDARY
EXTENDED FROM OFF THE NEW ENGLAND COAST SWWD THROUGH THE OH VALLEY
TO NRN AR...AND THEN INTO SRN OK TO WEST CENTRAL TX. MEANWHILE...
ANOTHER BOUNDARY WAS LOCATED OVER TX EXTENDING WWD FROM 40 ESE LFK
TO 30 NNW AUS AND THEN WSWWD TO THE TX BIG BEND REGION.
MOIST/MODERATELY UNSTABLE SELY UPSLOPE FLOW WILL CONTINUE TO SUPPORT
TSTM DEVELOPMENT ACROSS ERN NM...WHERE EFFECTIVE SHEAR AROUND 50 KT
WILL MAINTAIN LIKELIHOOD FOR ORGANIZED STORMS/SUPERCELLS. STEEP MID
LEVEL LAPSE RATES COMBINED WITH THE EFFECTIVE SHEAR WILL SUPPORT A
HAIL THREAT...WHILE LOW LEVEL DIRECTIONAL SHEAR WITH SFC-1 KM SRH
RANGING FROM 100-250 M2/S2 WILL MAINTAIN A THREAT FOR ISOLATED
TORNADOES. THREAT FOR SURFACE BASED SEVERE STORMS...INCLUDING THE
TORNADO THREAT...SHOULD BE CONFINED TO ERN NM AND SWD INTO SW
TX...SINCE AREAS FARTHER EAST REMAIN MORE STABLE IN THE LOW LEVELS.
THE SLIGHT RISK AREA HAS BEEN EXTENDED FARTHER NWD THROUGH THE TX
PANHANDLE AND INTO FAR WRN OK...GIVEN THE POTENTIAL FOR INCREASING
ELEVATED STORMS...NORTH OF THE SYNOPTIC BOUNDARY IN WEST CENTRAL TX.
THIS NEW ACTIVITY...WITH REGIONAL RADARS AT 01Z ALREADY SHOWING A
COUPLE OF ISOLATED STORMS IN SWISHER/HUTCHINSON COUNTIES TX...WILL
BE AIDED BY INCREASING LOW LEVEL MOISTURE/WARM AIR ADVECTION ALONG A
STRENGTHENING NOCTURNAL SSELY LLJ ACROSS W TX. IN ADDITION...WATER
VAPOR IMAGERY INDICATED A SRN STREAM IMPULSE...CURRENTLY MOVING
ACROSS SONORA MEXICO. FORCING FOR ASCENT WILL INCREASE ACROSS THE
SRN HIGH PLAINS LATER THIS EVENING/OVERNIGHT AS THIS MID LEVEL
FEATURE APPROACHES THIS AREA...FURTHER ENHANCING THE LIKELIHOOD FOR
TSTM DEVELOPMENT. STEEP MID LEVEL LAPSE RATES /PER AMA/ABQ 00Z
SOUNDINGS AND FORECAST SOUNDINGS/...COMBINED WITH MUCAPE TO AROUND
1000 J/KG AND EFFECTIVE BULK SHEAR AROUND 50 KT WILL SUPPORT AN
ELEVATED HAIL THREAT WITH SUPERCELLS POSSIBLE. ACTIVITY COULD
EVOLVE INTO AN MCS AND PROGRESS EWD INTO WRN OK LATER TONIGHT AS THE
LLJ VEERS TO MORE SLY.
...PARTS OF CENTRAL TX...
THOUGH NOT EASILY DISCERNIBLE IN WATER VAPOR IMAGERY...18Z NAM/GFS
BOTH INDICATED A 50 KT WSWLY MID LEVEL JET STREAK WILL TRACK FROM
NRN MEXICO ACROSS THE TX BIG BEND REGION TO CENTRAL TX THIS FORECAST
PERIOD. ASCENT WITH THIS FEATURE AND INCREASING EFFECTIVE BULK
SHEAR SUGGEST ANY TSTMS THAT CAN DEVELOP ALONG THE CENTRAL TX
SURFACE BOUNDARY WILL POSE A THREAT FOR AT LEAST ISOLATED
SEVERE...GIVEN A MODERATELY UNSTABLE AIR MASS ALREADY IN PLACE.
..PETERS.. 04/29/2009
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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