SPC AC 021242
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0742 AM CDT SUN MAY 02 2010
VALID 021300Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL GULF CST/TN VLY
TO THE MID ATLANTIC STATES/LWR GRT LKS...
...SYNOPSIS...
POSITIVE TILT CNTRL STATES TROUGH WILL DEAMPLIFY THIS PERIOD AS MAIN
ATTENDANT SHORTWAVE IMPULSE...NOW OVER THE CNTRL/SRN PLNS...SHEARS
NE ACROSS THE MID MS/LWR OH VLYS TO THE ERN GRT LKS. A LWR LATITUDE
DISTURBANCE NOW OVER NRN MEXICO SHOULD ALSO SHEAR NEWD...WITH
ASSOCIATED HEIGHT FALLS GLANCING THE LWR MS/LWR TN VLYS.
ELSEWHERE...WEAK CYCLONIC FLOW WILL PREVAIL OVER THE CNTRL PLNS...ON
S SIDE OF MB/ONT UPR LOW.
AT LWR LVLS...SFC LOW WITH CNTRL PLNS IMPULSE WILL ELONGATE NEWD
FROM IND INTO SW QUE BY THIS EVE AS TRAILING CDFNT MOVES E ACROSS
THE UPR OH VLY/LWR GRT LKS. THE FRONT WILL BE PRECEDED BY SQLN/RAIN
BAND LEFT FROM OVERNIGHT STORMS IN THE TN VLY. FARTHER S...LOW LVL
CONFLUENCE ZONE EXPECTED TO PERSIST TODAY OVER ERN TN/ERN MS AND
AL...AHEAD OF SYNOPTIC COLD FRONT OVER LA/WRN MS.
...UPR TN VLY/SRN APPALACHIANS TO CNTRL GULF CST...
AFOREMENTIONED PRE-FRONTAL CONFLUENCE BAND SHOULD REMAIN THE MAIN
FOCUS FOR STRONG TO SVR STORMS FROM ERN KY/TN SSW INTO ERN MS/AL AND
NW GA TODAY/TONIGHT. WITH LITTLE OVERALL CHANGE IN THE LARGE SCALE
SETUP EXPECTED /DEEP...STRONG...LARGELY UNIDIRECTIONAL SSW FLOW AND
PW APPROACHING 2.00 INCHES/...ADDITION OF SFC HEATING TO THE WEAKLY
CAPPED ENVIRONMENT SHOULD INCREASE THE LIKELIHOOD FOR
STORM/SUPERCELL ECHO TRAINING. THIS ACTIVITY WILL FOSTER A
DIURNALLY-ENHANCED THREAT FOR BOTH TORNADOES AND SMALL SCALE BOWS
WITH DMGG WIND...IN ADDITION TO HEAVY RAIN.
...MID ATLANTIC/NERN STATES...
STRONG/BROAD SSWLY LLJ AHEAD OF UPR SYSTEM SHEARING NE TOWARD THE
LWR GRT LKS WILL SPREAD INCREASING MOISTURE ACROSS THE NERN U.S.
TODAY...WITH PW RANGING FROM 1.50 TO NEARLY 2.00 INCHES AND SFC DEW
POINTS IN THE 60S F. LARGE SCALE FORCING FOR ASCENT WILL BE
WEAK...AND CLOUDS/LOW LVL OUTFLOW FROM OVERNIGHT STORMS IN THE OH
VLY WILL SOMEWHAT LIMIT DAYTIME DESTABILIZATION. BUT WITH AT LEAST
1000-1500 J/KG OF WEAKLY-CAPPED SBCAPE EXPECTED OVER MD/PA/NY...AND
50-70 KT WSWLY MID LVL FLOW...POTENTIAL WILL EXIST FOR A FEW
LOOSELY-ORGANIZED BANDS/CLUSTERS OF SUSTAINED STORMS/SUPERCELLS.
THESE COULD YIELD HAIL/DMGG WIND AND...GIVEN FAVORABLE LOW LVL
MESOSCALE CONDITIONS...A COUPLE TORNADOES.
...CNTRL PLNS/LWR MO VLY...
RELATIVELY COLD MID-LVL TEMPERATURES /MINUS 22-MINUS 24 C AT 500 MB/
WILL PREVAIL OVER THE CNTRL PLNS AHEAD OF WEAK COLD FRONT NOW OVER
SD. CONVERGENCE ALONG/AHEAD OF FRONT...STRONG HEATING...AND MODEST
MOISTURE MAY SUPPORT SCTD MAINLY DIURNAL MULTICELL TSTMS FROM ERN CO
EWD INTO PARTS OF IA/MO. STEEP LOW TO MID LVL LAPSE RATES SUGGEST
THAT STRONGER STORMS MAY PRODUCE HAIL/GUSTY WINDS.
..CORFIDI/GARNER.. 05/02/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
|
