SWODY1
SPC AC 071239
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0739 AM CDT WED SEP 07 2011
VALID 071300Z - 081200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE MID ATLANTIC
STATES...
...SYNOPSIS...
REMNANT UPR LOW ASSOCIATED WITH FORMER T.D. LEE...NOW OVER ERN
KY...WILL DRIFT ONLY VERY SLOWLY N THIS PERIOD AS THE WLYS REMAIN
WELL TO THE NORTH IN CANADA...AND BLOCKING RIDGES PERSIST OVER THE
NRN RCKYS AND N ATLANTIC. REMNANT LOW LVL CIRCULATION OF LEE...NOW
IN SW VA...SHOULD FURTHER WEAKEN AS IT REFORMS W/NW ACROSS WV
TODAY...AND INTO OH TNGT/EARLY THU. SHALLOW SW-NE FRONT EXTENDING
NEWD FROM LEE ACROSS ERN MD INTO SRN NJ EXPECTED TO ADVANCE FARTHER
NW ACROSS CNTRL MD/SE PA AND PARTS OF NJ TODAY/TNGT.
...MID-ATLANTIC/DELMARVA THIS AFTN/EVE...
DEEP UNIDIRECTIONAL SLY FLOW/WARM CONVEYOR BELT ON E SIDE OF KY/OH
UPR LOW...WITH PW AOA 2 INCHES...WILL REMAIN NEARLY STNRY ACROSS THE
CNTRL APPALACHIANS AND THE ADJACENT PIEDMONT THROUGH TNGT AS THE LOW
DRIFTS/ELONGATES SLOWLY NWD. EXTENSIVE...N-S CONVECTIVE BAND WITHIN
THE CONVEYOR BELT...NOW EXTENDING FROM NEAR RIC TO NEAR
BWI/MDT...LIKEWISE ALSO WILL EXHIBIT LITTLE NET EWD MOVEMENT. AT
THE SAME TIME...SHALLOW SW-NE WARM FRONT WILL ADVANCE SLOWLY NW
ACROSS PARTS OF VA...MD...SE PA...AND SRN NJ TODAY...LEAVING A
NARROWING TONGUE OF RESIDUAL COOLER LOW LEVEL AIR DAMNED ALONG THE
ERN SLOPES OF THE MOUNTAINS FROM CNTRL VA INTO S CNTRL PA.
MID LVL LAPSE RATES ACROSS REGION WILL REMAIN WEAK. BUT WITH SFC
DEWPOINTS RISING INTO THE LOW TO MID 70S F...DAYTIME HEATING ALONG
AND SE OF THE WARM FRONT SHOULD BOOST SBCAPE TO AROUND 1500 J/KG.
COUPLED WITH CONFLUENT LOW LVL FLOW IN ERN QUADRANT OF VERTICALLY
STACKED SFC AND UPR LVL LOWS...SETUP SHOULD SUPPORT INTENSIFICATION
OF THE CONVECTIVE BAND...ESPECIALLY AS IT BECOMES NEARLY CO-LOCATED
WITH THE FRONT. MORE WIDELY SCTD SHOWERS/STORMS MAY FORM E/S OF THE
FRONT ACROSS THE CHESAPEAKE BAY...THE DELMARVA PENINSULA...AND
SRN/CNTRL NJ.
ALTHOUGH LOW TO MID TROPOSPHERIC WINDS WITH THE REMNANTS OF LEE WILL
BE DIMINISHED RELATIVE TO RECENT DAYS...CURRENT OBSERVATIONS AND
MODEL FCSTS SUGGEST THAT SUFFICIENT /35+ KT/ UNIDIRECTIONAL SLY FLOW
IN THE 850-500 MB LAYER WILL REMAIN PRESENT TO SUPPORT SUSTAINED
STORMS WITH SMALL BOWS AND LOCALLY DMGG WIND. THE POSSIBILITY ALSO
WILL EXIST FOR LOW LVL MESOCYCLONES/INTERMITTENT SUPERCELL
STRUCTURES POSING A RISK FOR TORNADOES GIVEN THAT NEAR-SFC FLOW
LIKELY WILL REMAIN SELY...ESPECIALLY NEAR WARM FRONT.
THE GREATEST SVR RISK SHOULD EXIST FROM MIDDAY THROUGH EARLY THIS
EVE...WITH WEAKENING INSTABILITY/WINDS YIELDING A MUCH DIMINISHED
THREAT TNGT. THROUGHOUT THE PERIOD...COMBINATION OF HIGH PW WITH
DEEP UNIDIRECTIONAL FLOW AND MINIMAL PROGRESSION OF N-S CONVEYOR
BELT WILL YIELD A SERIOUS THREAT FOR CONVECTIVELY-ENHANCED FLASH
FLOODING /SEE HPC FORECASTS FOR DETAILS/.
..CORFIDI/GARNER.. 09/07/2011
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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