SWODY1
SPC AC 171630
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT SAT MAR 17 2012
VALID 171630Z - 181200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR
PARTS OF THE MID MS AND LOWER OH VALLEYS...
...SYNOPSIS...
A DEEP MID-UPPER LEVEL TROUGH OVER THE PAC COAST WILL CONTINUE TO
PROGRESS INLAND TO THE GREAT BASIN/LOWER CO RIVER VALLEY BY 12Z
SUNDAY. A FEW LIGHTNING STRIKES WILL BE POSSIBLE ALONG THE ORE/CA
COASTS AS THE COLD AIR ALOFT AND STEEP LAPSE RATES SPREAD INLAND
TODAY...AS WELL AS ALONG THE PRIMARY BAROCLINIC ZONE WITH WEAK
INSTABILITY ACROSS THE ERN GREAT BASIN THIS AFTERNOON.
DOWNSTREAM...A LARGE SCALE RIDGE WILL REMAIN OVER THE ERN
CONUS...WITH WEAK FLOW AND MODEST INSTABILITY EXPECTED E OF THE MS
RIVER VALLEY. FROM THE MS RIVER VALLEY TO THE ERN PLAINS
STATES...LOW-LEVEL MOISTURE RETURN WILL PERSIST IN RESPONSE TO HIGH
PLAINS LEE CYCLOGENESIS. BOUNDARY LAYER DEWPOINTS IN THE 60S WILL
COVER A WIDE SWATH FROM THE UPPER MS VALLEY SWD TO THE SRN
PLAINS/LOWER MS VALLEY...THOUGH THE MAJORITY OF THE ERN PLAINS
STATES WILL REMAIN CAPPED BENEATH A RELATIVELY WARM EML.
...MID MS/LOWER OH VALLEY REGION THIS AFTERNOON...
A WEAK MIDLEVEL TROUGH OVER SW MO/NW AR WILL MOVE SLOWLY EWD/ENEWD
TOWARD THE LOWER OH VALLEY BY TONIGHT. REGIONAL 12Z SOUNDINGS AGAIN
REVEAL THE POTENTIAL FOR MODERATE INSTABILITY THIS AFTERNOON...AND
AN INITIAL CLUSTER OF ELEVATED CONVECTION OVER CENTRAL MO WILL
LIKELY BECOME SURFACE BASED BY EARLY AFTERNOON. IT APPEARS THAT
BACKED AND RELATIVELY WEAK MID-UPPER FLOW IN THE ZONE OF ASCENT
PRECEDING THE MIDLEVEL TROUGH WILL PROMOTE MAINLY MULTICELL CLUSTERS
WITH A MARGINAL HAIL/WIND RISK. THOUGH THERE WILL BE LITTLE SURFACE
REFLECTION OF THIS MIDLEVEL TROUGH...A BELT OF 30-40 KT MIDLEVEL
FLOW IN CONJUNCTION WITH BACKGROUND SLY/SWLY LOW-LEVEL FLOW WILL
PROVIDE SUFFICIENT VERTICAL SHEAR FOR SUPERCELL STRUCTURES THIS
AFTERNOON ACROSS SRN MO/AR ALONG THE SRN/SWRN FLANK OF THE WAVE
ALOFT...THOUGH ASCENT AND STORM COVERAGE WILL BE MORE QUESTIONABLE
ACROSS THIS AREA.
...SE ATLANTIC COASTAL PLAIN THIS AFTERNOON...
WEAK WLY LOW-LEVEL FLOW INLAND AND SURFACE HEATING THIS AFTERNOON
WILL ALLOW THE DEVELOPMENT OF A WEAK SEA BREEZE NEAR THE ATLANTIC
COAST. LAPSE RATE PROFILES ARE SIMILAR TO PREVIOUS DAYS...AND
SCATTERED AFTERNOON THUNDERSTORM ARE AGAIN EXPECTED. THE WEAK
VERTICAL SHEAR ENVIRONMENT WILL FAVOR PULSE-TYPE STORMS CAPABLE OF
PRODUCING MARGINALLY SEVERE HAIL GIVEN 500 MB TEMPERATURES NEAR -15
C...AS WELL AS ISOLATED STRONG OUTFLOW GUSTS.
..THOMPSON/LEITMAN.. 03/17/2012
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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