DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 011615
SWODY1
SPC AC 011613

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1113 AM CDT THU AUG 01 2013

VALID 011630Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN ROCKIES TO MID MO
VALLEY AND CNTRL PLAINS...

...SYNOPSIS...

THE LARGE-SCALE PATTERN WILL CHANGE LITTLE THROUGH THE D1 PERIOD
WITH A LONG-WAVE TROUGH FROM HUDSON BAY TO THE SRN ATLANTIC
COAST...AN UPPER-LEVEL LOW OVER THE PACIFIC NW...AND A GRADUALLY
DAMPENING RIDGE CENTERED ACROSS THE SRN HIGH PLAINS. ONE
POTENTIALLY SALIENT FEATURE TO CONVECTIVE DEVELOPMENT IS A
SHORT-WAVE TROUGH WHICH WILL TRANSLATE FROM THE BASE OF PACIFIC NW
UPPER LOW NEWD INTO THE NRN ROCKIES.

IN THE LOW LEVELS...A WAVY QUASI-STATIONARY BOUNDARY EXTENDING FROM
A LEE CYCLONE OVER WRN MT SEWD THROUGH THE MID MO VALLEY MAY
INTENSIFY WHILE SLOWLY DEVELOPING NWD. ELSEWHERE...A COLD FRONT
FROM THE UPPER OH VALLEY TO SRN APPALACHIANS WILL PROGRESS EWD
TOWARD THE ATLANTIC COAST.

...NRN HIGH PLAINS INTO THE MID MO VALLEY THIS AFTERNOON INTO
TONIGHT...

MULTIPLE CLUSTERS OF ELEVATED TSTMS ARE ONGOING FROM THE BLACK HILLS
SWD/SEWD ACROSS NEB WITH ACTIVITY LARGELY BEING FORCED BY A
DIURNALLY WEAKENING LOW-LEVEL WIND MAXIMUM. LATEST MODEL GUIDANCE
SUGGESTS THAT A SUBSET OF THESE STORMS MAY PERSIST TODAY --LIKELY
INTENSIFYING AND BECOMING SURFACE BASED-- AS THE LOW-LEVEL JET
RE-INTENSIFIES OWING TO THE COUPLING WITH THE RIGHT ENTRANCE REGION
OF AN UPPER-LEVEL JET STREAK ACROSS THE UPPER MIDWEST. ADDITIONAL
STORMS ARE EXPECTED TO FORM THIS AFTERNOON ACROSS ERN WY/WRN SD
ALONG THE SYNOPTIC FRONT AND FAVORED TERRAIN.

THE COLOCATION OF A RELATIVELY MOIST BOUNDARY LAYER /I.E.
LOWEST-100-MB MEAN-MIXING RATIOS OF 11-12 G PER KG/ BENEATH STEEP
MIDLEVEL LAPSE RATES WILL RESULT IN THE DEVELOPMENT OF MODERATE
AFTERNOON INSTABILITY WITH MLCAPE VALUES APPROACHING 1500-3000 J/KG.
THIS INSTABILITY WILL COINCIDE WITH A KINEMATIC ENVIRONMENT
FEATURING A VERTICALLY VEERING WIND PROFILE WITH 40-50 KT OF
DEEP-LAYER SHEAR. AS SUCH...INITIAL STORM MODES WILL LIKELY BE
SUPERCELLULAR WITH A RISK FOR VERY LARGE HAIL AND POSSIBLY A COUPLE
OF TORNADOES. THE INTENSIFICATION OF A SLY NOCTURNAL LOW-LEVEL WIND
MAXIMUM WILL PROMOTE UPSCALE GROWTH OF STORMS INTO SEWD-MOVING
CLUSTERS TONIGHT WITH A CONTINUED RISK FOR DAMAGING WINDS AND HAIL.

...NRN ROCKIES THIS AFTERNOON AND EVENING...

FORCING FOR ASCENT/DCVA ATTENDANT TO THE SHORT-WAVE TROUGH PIVOTING
AROUND THE PARENT UPPER-LEVEL LOW WILL AUGMENT TERRAIN-ENHANCED
CIRCULATIONS TO FOSTER SCATTERED TSTMS THIS AFTERNOON. WHILE THE
ENVIRONMENT IS NOT OVERLY MOIST...THE PRESENCE OF STEEP LAPSE RATES
AND AMPLE DEEP-LAYER SHEAR WILL SUPPORT THE DEVELOPMENT OF
HIGH-BASED SUPERCELLS CAPABLE OF DAMAGING WINDS AND LARGE HAIL WITH
THIS THREAT SPREADING EWD/NEWD INTO THE HIGH PLAINS OF CNTRL MT THIS
EVENING.

...NORTHEAST/MID ATLANTIC STATES THIS AFTERNOON AND EVENING...

FORCING FOR ASCENT/DCVA WILL INCREASE ACROSS THE REGION TODAY IN
RESPONSE TO THE ENEWD PROGRESSION OF A SHORT-WAVE TROUGH ACROSS THE
LOWER GREAT LAKES. WHEN COUPLED WITH LOW-LEVEL UPLIFT ALONG THE
COLD FRONT...EXPECT AN INCREASE IN STORM COVERAGE THIS AFTERNOON.
BREAKS IN THE CLOUDS MAY ALLOW FOR CORRIDORS OF GREATER
DESTABILIZATION AND THE POTENTIAL FOR LOCALLY STRONG TO SEVERE STORM
DEVELOPMENT WITH THE PRIMARY HAZARD BEING DAMAGING WIND GUSTS.
HOWEVER...GENERALLY WEAK VERTICAL SHEAR AND FAIRLY
WIDESPREAD CLOUDS ARE EXPECTED TO LIMIT MORE ORGANIZED SEVERE
WEATHER POTENTIAL.

..MEAD/SMITH.. 08/01/2013

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