SWODY1
SPC AC 151624
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1124 AM CDT TUE MAY 15 2007
VALID 151630Z - 161200Z
..THERE IS A SLGT RISK OF SVR TSTMS FROM AR INTO THE GREAT
LAKES/NEW ENGLAND...
..OZARKS/MID SOUTH INTO THE CENTRAL GREAT LAKES...
SUNSHINE WILL BE ABUNDANT AHEAD OF SLOW MOVING SURFACE COLD
FRONT/PERSISTENT AREA OF CONVECTION MOVING INTO THE OZARKS/MID MS
RIVER VALLEY LATE THIS MORNING. IN ADDITION...ADVECTION AND
DOWNWARD MIXING IS BOOSTING SURFACE DEW POINTS INTO THE LOWER 60S
FROM AR INTO NRN/WRN IL AS OF 15Z. CONTINUED MIXING MAY LIMIT
FURTHER MOISTENING OR EVEN SUPPORT SOME DRYING NEAR THE SURFACE
DURING THE AFTERNOON. HOWEVER...STEEP LAPSE RATES AND STRONG
HEATING WILL LIKELY SUPPORT A LARGE AREA OF MODERATE INSTABILITY
ACROSS THIS REGION BY THE EARLY TO MID AFTERNOON. WITH WEAK
CONVERGENCE NEAR THE FRONT AND ADDED DEEP ASCENT AHEAD OF SLOW
MOVING MID/UPPER LEVEL TROUGH...THUNDERSTORMS ARE EXPECTED TO BECOME
NUMEROUS DURING THE AFTERNOON. MUCH OF THE ACTIVITY WILL EVOLVE
INTO MULTICELL CLUSTERS/LINES WITH DEEP LAYER SHEAR BETWEEN 20-30
KT. HOWEVER...STRONGER SHEAR SHOULD SUPPORT GREATER ORGANIZATION
AND POSSIBLY SUPERCELLS INTO LOWER MI. A LIMITING FACTOR TODAY WILL
BE THE WEAK CONVERGENCE ACROSS THE MIDWEST AS SURFACE WINDS
CONTINUE TO VEER ACROSS THE WARM SECTOR. THIS SHOULD ALSO LIMIT LOW
LEVEL SHEAR AND RESULTANT TORNADO POTENTIAL IS EXPECTED TO REMAIN
MINIMAL. HOWEVER...THE THREATS OF LARGE HAIL AND DAMAGING WIND WILL
SLOWLY RAMP-UP THROUGH THE LATE MORNING AND EARLY AFTERNOON. AS
ACTIVITY BECOMES MORE ORGANIZED LATER TODAY...SEVERE THREAT SHOULD
PERSIST THIS EVENING INTO OH RIVER VALLEY AND GREAT LAKES REGIONS.
..LOWER GREAT LAKES ACROSS PORTIONS OF SRN NEW ENGLAND...
SURFACE LOW IS FORECAST TO TRACK EWD ACROSS SRN ONTARIO TODAY AS
WARM FRONT BECOMES ESTABLISHED E-W ACROSS CENTRAL NY AND INTO SRN
NEW ENGLAND. SOME CONCERNS THIS MORNING REGARDING EXTENSIVE
CLOUDINESS OVER ERN MA INTO NRN NEW ENGLAND...WHICH MAY RETARD
HEATING EARLY THIS AFTERNOON. HOWEVER...CLEARING SKIES WILL SPREAD
EWD THROUGH THE AFTERNOON. RELATIVELY DRY SURFACE LAYER IS
ADDITIONAL CONCERN...THOUGH DOWNWARD MIXING AND ADVECTION SHOULD
ALLOW SURFACE DEW POINTS TO INCREASE INTO THE LOWER 50S ACROSS
SRN/CENTRAL NEW YORK INTO AT LEAST WRN NEW ENGLAND. EXPECT AN
ISOLATED THUNDERSTORM OR TWO BY LATER TODAY ACROSS THIS
REGION...WITH ADDITIONAL STORMS POSSIBLY SPREADING QUICKLY EWD OUT
OF ONTARIO. DESPITE THE MARGINAL INSTABILITY...STEEP LAPSE RATES
AND VERY STRONG SHEAR SUPPORT A THREAT OF ORGANIZED LINES AND
POSSIBLY SUPERCELLS. DAMAGING WINDS MAY BE PRIMARY SEVERE
THREAT...ALONG WITH LARGE HAIL.
..FAR SWRN TX INTO WRN NEW MEXICO...
RELATIVELY COOL MID LEVEL TEMPERATURES WILL OFFSET MODEST SURFACE
DEW POINTS ACROSS THIS REGION. THIS SHOULD SUPPORT MARGINAL TO
MODERATE INSTABILITY WEST OF SURFACE COLD FRONT NOW PUSHING SWD OVER
THE HIGH PLAINS OF WEST TX/ERN NM. THOUGH DEEP LAYER SHEAR IS
EXPECTED TO REMAIN MODEST AT 25-35 KT...STEEP LAPSE RATES AND COOL
TEMPERATURES ALOFT MAY SUPPORT A THREAT OF HAIL/WIND NEAR SEVERE
LEVELS LATER TODAY AND THIS EVENING.
..LOWER MS RIVER VALLEY/FAR ERN AND NRN TX/SRN OK/SRN AR...
ABUNDANT MOISTURE CONTINUES TO BE OVERSPREAD BY RELATIVELY COOL MID
LEVEL AIR IN PLACE OVER THIS REGION TODAY. LAPSE RATES ARE AGAIN
QUITE STEEP AND SHOULD SUPPORT MODERATE TO STRONG INSTABILITY BY THE
MID AFTERNOON. THOUGH ACTIVITY WILL REMAIN QUITE
DISORGANIZED...BRIEF HAIL/WIND EVENTS EXCEEDING SEVERE LEVELS WILL
BE POSSIBLE INTO THE EARLY EVENING. WEAK CONVERGENCE SHOULD KEEP
ACTIVITY LESS FOCUSED THAN YESTERDAY AND WILL OPT TO KEEP LOW SEVERE
PROBABILITIES ATTM.
.EVANS/GRAMS.. 05/15/2007
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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:
Post a Comment