DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 010558
SWODY1
SPC AC 010555

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT MON APR 01 2013

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS SRN TX PANHANDLE TO THE TX LOW
ROLLING PLAINS AND FAR SWRN OK...

...SYNOPSIS...
A CLOSED LOW CENTERED ALONG THE CENTRAL CA/NV BORDER AT 12Z TODAY
WILL SHIFT SLOWLY EWD THROUGH THE GREAT BASIN. GIVEN THIS FEATURE
WILL BE MOVING THROUGH THE MEAN WRN STATES RIDGE...FURTHER WEAKENING
OF THE LOW IS EXPECTED. ZONAL FLOW WILL EXTEND FROM THE SRN
PERIPHERY OF THE WRN LOW TO THE SRN PLAINS...GULF COAST AND SERN
STATES. MEANWHILE...STRONGEST MID-UPPER LEVEL WINDS WILL REMAIN
OVER THE UPPER MIDWEST TO OH VALLEY AND NERN STATES WITHIN CYCLONIC
FLOW ATTENDANT TO A VORTEX PIVOTING ENEWD FROM SRN ONTARIO/LOWER
GREAT LAKES INTO SRN QUEBEC AND THE NERN STATES.

IN THE LOW LEVELS...A COLD FRONT WILL TRAIL SSWWD FROM SERN ONTARIO
/ATTENDANT TO THE SRN ONTARIO VORTEX/ THROUGH WRN PA TO MIDDLE
TN...AND THEN WWD THROUGH NRN AR TO NRN OK TO THE OK PANHANDLE. THE
NRN EXTENT OF THIS FRONT WILL ADVANCE THROUGH THE NERN STATES AND
SHOULD BE E OF NEW ENGLAND AFTER 02/00Z. THE SRN PLAINS PORTION OF
THIS BOUNDARY WILL SHIFT SWD TODAY...WITH THE WRN EXTENT BEING THE
PRIMARY FOCUS FOR LATE AFTERNOON/EVENING TSTM DEVELOPMENT OVER NWRN
TX.

...SRN TX PANHANDLE TO THE TX LOW ROLLING PLAINS AND FAR SWRN OK...
SLY LOW LEVEL WINDS DEVELOPING S OF THE COLD FRONT WILL ALLOW
MOISTURE TO RETURN NWD...THOUGH SURFACE DEWPOINTS IN THE MID 50S
SHOULD ONLY REACH WRN PORTIONS OF NORTH CENTRAL TX...WITH VALUES IN
THE MID-UPPER 40S EXPECTED TO EXTEND WNWWD INTO THE SRN TX PANHANDLE
AND WEST CENTRAL TX. THE LACK OF STRONGER FORCING FOR ASCENT...
GIVEN SHORTWAVE RIDGING ACROSS THE SRN HIGH PLAINS...SUGGESTS STRONG
DIABATIC HEATING WITHIN WEAK MOISTURE RETURN AND CONVERGENCE INVOF
THE COLD FRONT AND N-S BOUNDARY IN W TX WILL BE NEEDED FOR TSTM
DEVELOPMENT. THIS LACK IN STRONGER FORCING ALOFT MAY TEND TO LIMIT
OVERALL COVERAGE OF INITIAL TSTMS. A FEW HIGH BASED STORMS WILL BE
POSSIBLE BY LATE AFTERNOON...MAINLY ACROSS THE WRN PORTION OF THE
SLIGHT RISK AREA --- THOUGH A STORM WILL BE POSSIBLE FARTHER S INTO
SWRN TX /NEAR AND S OF KMAF/. STEEP MIDLEVEL LAPSE RATES AND STRONG
SURFACE HEATING SHOULD RESULT IN MLCAPE OF 1000-1500 J/KG. THIS
COMBINED WITH VERTICALLY VEERING WIND PROFILES AND EFFECTIVE BULK
SHEAR OF 40-50 KT WILL SUPPORT SUPERCELLS. IN ADDITION TO
HAIL...STEEP LAPSE RATES AND HIGH BASED INITIAL ACTIVITY WILL FAVOR
A THREAT FOR STRONG WIND GUSTS.

A LOW TORNADO PROBABILITY HAS BEEN INTRODUCED OVER THE W-SWRN PART
OF THE SLIGHT RISK AREA...WHERE FORECAST SOUNDINGS SUGGEST THE
ENVIRONMENT MAY BECOME SUPPORTIVE OF A TORNADO AS LOW LEVEL SHEAR
INCREASES ALONG A STRENGTHENING SLY LLJ AND WITHIN A MOISTENING...
BUT COOLING BOUNDARY LAYER. THIS POTENTIAL SHOULD BE RATHER
SHORT-LIVED AS TSTMS WILL LIKELY BECOME ELEVATED AS ACTIVITY SPREADS
ESEWD WITHIN AN INCREASING ZONE OF WAA ALONG AND N OF THE COLD
FRONT. HAIL WILL THEN BE THE PRIMARY THREAT...POTENTIALLY REACHING
WRN PORTIONS OF THE DFW METROPLEX AND PART OF SWRN OK THIS EVENING
AND OVERNIGHT.

...ERN PART OF NEW ENGLAND...
POTENTIAL EXISTS FOR SUFFICIENT DESTABILIZATION ALONG AND JUST AHEAD
OF THE COLD FRONT...AS IT ADVANCES THROUGH ERN PORTIONS OF NEW
ENGLAND...TO SUPPORT LOW-TOPPED TSTM DEVELOPMENT. THIS CONVECTIVE
THREAT SHOULD OCCUR BETWEEN 18-00Z. A LOCALLY STRONG WIND GUST OR
TWO CANNOT BE RULED OUT...BUT SOME UNCERTAINTY IN OVERALL CONVECTIVE
COVERAGE PRECLUDES THE INCLUSION OF LOW SEVERE WIND PROBABILITIES.

..PETERS/COHEN.. 04/01/2013

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.