DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 281620
SWODY1
SPC AC 281618

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1118 AM CDT THU MAR 28 2013

VALID 281630Z - 291200Z

...NO SVR TSTM AREAS FORECAST...

...SWRN TX NEWD INTO THE MID MS VALLEY THIS AFTERNOON INTO
TONIGHT...
AS QUASI-ZONAL MID-LEVEL FLOW OCCURS DOWNSTREAM OF A WEAKLY
AMPLIFYING RIDGE OVER THE INTERMOUNTAIN WEST...A SFC TROUGH WILL
STRENGTHEN IN THE LEE OF THE SRN ROCKIES. THIS WILL ENHANCE SLY/SELY
SFC FLOW OVER THE PLAINS...WHERE THE INFLUX OF PARTIALLY MODIFIED
GULF MOISTURE WILL CONTINUE TO THE W/NW OF A N-CNTRL/NERN GULF RIDGE
AND TO THE E OF A MODESTLY SHARPENING DRYLINE. A DIFFUSE FRONT
CURRENTLY STRETCHES FROM NW TX NEWD INTO THE MO OZARKS...AND WILL
MOVE LITTLE THROUGH THIS EVENING. THE DRYLINE IS FORECAST TO
INTERSECT THE FRONT AT A TRIPLE POINT OVER THE TX S PLAINS THIS
AFTERNOON.

THE STRONGEST LOW-LEVEL ASCENT WILL BE FOCUSED INVOF THE DRYLINE --
NEAR AND S/SSW OF THE TRIPLE POINT TO THE MOUNTAINS OF SW TX. THIS
MAY SUPPORT AN ISOLATED THUNDERSTORM OR TWO OVER THE ERN FRINGES OF
A STEEP -- NEAR DRY ADIABATIC -- LOW-LEVEL LAPSE RATE PLUME WHERE
MARGINAL INSTABILITY WILL BE PRESENT THIS AFTERNOON. GUSTY WINDS AND
PERHAPS SMALL HAIL WILL BE THE PRIMARY CONCERN WITH THIS ACTIVITY.
HOWEVER...CONVECTIVE COVERAGE AND INTENSITY WILL BE GREATLY LIMITED
BY THE LACK OF APPRECIABLE MID-LEVEL ASCENT...LIMITED LOW-LEVEL AND
DEEP MOISTURE...LIMITED BUOYANCY...AND ONLY WEAK LOW-LEVEL ASCENT.

A RELATIVE SPATIAL MINIMUM IN THUNDERSTORM ACTIVITY IS ANTICIPATED
THROUGH TONIGHT FROM SWRN OK INTO PORTIONS OF CNTRL OK...WHERE EVEN
WEAKER LOW-LEVEL ASCENT WILL BE PRESENT AMIDST AN ONLY WEAKLY
CONVERGENT SFC FRONT.

FARTHER NE INTO NERN OK...NWRN/N-CNTRL AR...CNTRL/SWRN MO...AND ERN
KS...THUNDERSTORM CHANCES WILL NOT INCREASE UNTIL THIS
EVENING...WHEN A STRENGTHENING LOW-LEVEL JET STREAM SUPPORTS
INCREASING ELEVATED WAA/ISENTROPIC ASCENT. ASCENT WILL BE MAXIMIZED
AT THE TERMINUS OF A 25-35-KT LOW-LEVEL JET MAXIMUM...OVER THE ERN
EDGE OF A STEEP MID-LEVEL LAPSE RATE PLUME ACCOMPANYING AN EML
OVERSPREADING THE SRN/CNTRL PLAINS. ELEVATED RETURN MOISTURE WILL
SUPPORT SUFFICIENT BUOYANCY WITHIN THE WARM ADVECTION REGIME FOR
ISOLATED TO SCATTERED ELEVATED THUNDERSTORMS ROOTED AROUND 850 MB --
POTENTIALLY ORGANIZING INTO ONE OR TWO CLUSTERS -- DURING THE LATE
EVENING AND ESPECIALLY DURING THE OVERNIGHT HOURS. SMALL HAIL WILL
BE THE GREATEST CONCERN WITH THIS ACTIVITY. THE SPATIAL DISPLACEMENT
OF THE STRONGER FORCING FOR ASCENT FROM THE STEEPER MID-LEVEL LAPSE
RATE PLUME WILL LIKELY MITIGATE THE POTENTIAL FOR SVR CONVECTION.

...PARTS OF THE NRN GREAT BASIN THIS AFTERNOON INTO THIS EVENING...
ISOLATED WEAK THUNDERSTORMS MAY OCCUR AS MINOR MID-LEVEL IMPULSES
MOVE THROUGH THE NRN FRINGES OF THE WRN CONUS RIDGE AMIDST MARGINAL
INSTABILITY AND TERRAIN-DRIVEN ASCENT. STORMS SHOULD DIMINISH DURING
THE EVENING AS STABILITY INCREASES OWING TO BOUNDARY-LAYER NOCTURNAL
COOLING.

..COHEN/HART.. 03/28/2013

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