Monday, April 23, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 240113
SWODY1
SPC AC 240110

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0810 PM CDT MON APR 23 2007

VALID 240100Z - 241200Z

..THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF ERN
COLORADO...FAR SWRN NEBRASKA...WRN AND CENTRAL KANSAS...NORTHWEST
OKLAHOMA INCLUDING THE ERN OK PANHANDLE...AND FAR NERN TX
PANHANDLE...

..THERE IS A SLGT RISK OF SVR TSTMS EXTENDS ACROSS THE CENTRAL AND
SRN PLAINS...

..THERE IS A SLGT RISK OF SVR TSTMS SOUTHWEST TX...

..CENTRAL/SRN PLAINS...
ASCENT WITH MID/UPPER LEVEL SHORT WAVE TROUGH...NOW MOVING EWD
ACROSS THE FOUR CORNERS REGION...WILL CONTINUE TO SPREAD OVER THE
SRN/CENTRAL HIGH PLAINS SUPPORTING AN INCREASE IN TSTM COVERAGE FROM
ERN CO INTO WRN AND CENTRAL KS THIS FORECAST PERIOD. MODELS REMAIN
CONSISTENT WITH SUGGESTING THIS SCENARIO. STRENGTHENING SSWLY MID
LEVEL WINDS TO 70-80 KT INTO ERN CO/WRN KS AND SRN HIGH PLAINS ATOP
STRENGTHENING SLY LLJ IN RESPONSE TO HEIGHT FALLS WILL MAINTAIN
STRONG DEEP LAYER AND LOW LEVEL SHEAR FOR SUPERCELLS WITH BOTH
TORNADOES AND VERY LARGE AND DAMAGING HAIL THE PRIMARY THREATS.
ELEVATED ACTIVITY LATER TONIGHT MAY REACH PARTS OF SRN NEB WITH HAIL
BEING THE PRIMARY THREATS THIS FAR NORTH.

FURTHER S ACROSS THE TX PANHANDLE...A WEAK MID LEVEL INVERSION BASED
AROUND 600 MB AS INDICATED BY 00Z AMA SOUNDING APPEARS TO BE
LIMITING STRONGER TSTM DEVELOPMENT EARLY THIS EVENING IN AN AIR MASS
OTHERWISE CHARACTERIZED BY MODERATE INSTABILITY AND STRONG DEEP AND
LOW LEVEL LAYER SHEAR. THE LOSS OF DAYTIME HEATING....DRY LINE
RETREATING WWD INTO THE WRN PARTS OF THE OK/TX PANHANDLES...AND WARM
FRONT MOVING NWD THROUGH KS WOULD SUGGEST A LOW POTENTIAL FOR
ADDITIONAL TSTM DEVELOPMENT ACROSS OK/TX PANHANDLES.

..PARTS OF W...CENTRAL AND SW TX...
STRONG ASCENT WITH SUB-TROPICAL SHORT WAVE TROUGH...NOW LOCATED OVER
THE TRANS-PECOS REGION OF SW TX PER WATER VAPOR IMAGERY...WILL
CONTINUE TO SPREAD NEWD ACROSS WEST/CENTRAL TX AND REACH ARKLATEX
AND AR BY 12Z TUESDAY. AIR MASS SHOULD REMAIN UNSTABLE AND
SUFFICIENTLY SHEARED FOR ADDITIONAL ROTATING UPDRAFTS WITH CONTINUED
POTENTIAL FOR ISOLATED TORNADOES...LARGE HAIL AND DAMAGING WINDS.

..NY SWWD TO UPPER OH VALLEY...
WATER VAPOR IMAGERY INDICATED A PROGRESSIVE AND AMPLIFIED SHORT WAVE
TROUGH LOCATED OVER THE LOWER GREAT LAKES/UPPER OH VALLEY WITH THIS
FEATURE EXPECTED TO MOVE EWD THROUGH THE NERN STATES OVERNIGHT.
ENHANCED LOW TO MID LEVEL DRYING WAS ALSO INDICATED ON WATER VAPOR
IMAGERY IMMEDIATELY UPSTREAM WITH THIS MID LEVEL TROUGH. LOSS OF
DAYTIME HEATING IS EXPECTED TO FURTHER DECREASE CONVECTIVE
INSTABILITY THAT IS ALREADY RATHER WEAK. ADDITIONAL TSTMS SHOULD
DEVELOP ALONG COLD FRONT AS IT PROGRESSES EWD THROUGH NY INTO
CENTRAL AND SWRN PA...NRN WV AND SERN OH THIS EVENING. WEAK
INSTABILITY SHOULD LIMIT ADDITIONAL SEVERE THREAT. HOWEVER...
ISOLATED WIND GUSTS WILL REMAIN POSSIBLE GIVEN THE COMBINATION OF
THE APPROACH OF MID LEVEL DRYING...LARGE PRE-FRONTAL SURFACE
DEWPOINT DEPRESSIONS ENHANCING DOWNWARD MOMENTUM TRANSFER OF 50 KT
SWLY LLJ.

.PETERS.. 04/24/2007

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