DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 140519
SWODY1
SPC AC 140516

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1216 AM CDT MON MAY 14 2012

VALID 141200Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE BIG BEND
COUNTRY...SOUTHWEST TX AND SOUTHEAST NM...

...BIG BEND COUNTRY/SW TX/SE NM...
A POSITIVELY-TILTED UPPER-LEVEL TROUGH WILL MOVE SEWD ACROSS THE SRN
ROCKIES AND SRN PLAINS TODAY. AHEAD OF THE UPPER-LEVEL TROUGH...SFC
DEWPOINTS ARE FORECAST TO BE IN THE MID TO UPPER 50S F FROM ERN
PARTS OF THE BIG BEND COUNTRY NEWD ACROSS THE TX HILL COUNTRY. THE
MODELS DEVELOP AN AXIS OF MODERATE INSTABILITY BY AFTERNOON ACROSS
NRN MEXICO WEST OF THE RIO GRANDE RIVER EXTENDING NNWWD INTO THE BIG
BEND COUNTRY. AT THE SAME TIME...THE MODELS MOVE A MID-LEVEL
VORTICITY MAX SEWD ACROSS THE PECOS REGION WITH CONVECTION
INITIATING THIS AFTERNOON JUST AHEAD OF THE VORTICITY MAX. SOME OF
THE MODELS APPEAR TO BE DEVELOPING AN MCS AND MOVING THIS FEATURE
SEWD INTO NRN MEXICO AND ACROSS PARTS OF SW TX.

FORECAST SOUNDINGS LATE THIS AFTERNOON ACROSS THE SLIGHT RISK AREA
SHOW MLCAPE VALUES OF 1000 TO 1500 J/KG WITH STEEP MID-LEVEL LAPSE
RATES ABOVE 700 MB APPROACHING 8.0 C/KM. IN ADDITION...STRONG DEEP
LAYER SHEAR IS FORECAST WITH 0-6 KM SHEAR IN 50 TO 60 KT RANGE. THIS
ENVIRONMENT SHOULD EASILY SUPPORT SUPERCELLS WITH LARGE HAIL. AN
ISOLATED TORNADO OR TWO COULD ALSO OCCUR AROUND OR JUST TO THE EAST
OF THE BIG BEND WHERE HODOGRAPHS ARE LOOPED IN THE LOWEST 3 KM. WIND
DAMAGE WILL ALSO BE POSSIBLE WITH SUPERCELLS AND COULD INCREASE
DURING THE EVENING IF A BOWING LINE-SEGMENT CAN ORGANIZE.

...ERN SEABOARD/SRN APPALACHIAN MTNS...
SOUTHWEST FLOW WILL BE IN PLACE ACROSS THE ERN STATES TODAY WITH A
BELT OF ENHANCED LOW-LEVEL FLOW ACROSS NC...VA AND THE MID-ATLANTIC.
MODERATE INSTABILITY SHOULD DEVELOP FURTHER TO THE SOUTHWEST FROM
CNTRL NC SSWWD INTO SCNTRL GA WHERE MLCAPE VALUES ARE FORECAST TO BE
FROM 1000 TO 1500 J/KG. IN ADDITION...FORECAST SOUNDINGS SHOW STEEP
LOW-LEVEL LAPSE RATES IN PLACE ACROSS MOST OF THE WARM SECTOR
SUGGESTING WIND DAMAGE WILL BE POSSIBLE AS STORM COVERAGE INCREASES
DURING THE AFTERNOON. ALTHOUGH INSTABILITY IS FORECAST TO BE WEAKER
ACROSS THE MID-ATLANTIC...A MARGINAL WIND DAMAGE THREAT COULD ALSO
OCCUR THERE DUE TO THE STRONGER LOW-LEVEL FLOW AND GREATER STORM
COVERAGE. AT THIS POINT...WILL GO WITH A BROAD 5 PERCENT WIND DAMAGE
PROBABILITY FROM THE ERN GULF COAST STATES NEWD TO THE MID-ATLANTIC
WHERE A LOW-END WIND DAMAGE THREAT SHOULD EXIST ACROSS A BROAD AREA
THIS AFTERNOON.

...UPPER MS VALLEY...
AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE SEWD ACROSS MANITOBA TODAY
AND APPROACH THE UPPER MS VALLEY. THE MODELS DEVELOP SOME
INSTABILITY LATE THIS AFTERNOON ACROSS ERN MN AND NW WI WITH
ISOLATED THUNDERSTORM DEVELOPMENT POSSIBLE. FORECAST SOUNDINGS
ACROSS THE UPPER MS VALLEY AT 03Z SHOW STEEP MID-LEVEL LAPSE RATES
OF 7.5 TO 8.0 C/KM SUGGESTING A THREAT FOR HAIL MAY EXIST. THE
SEVERE THREAT APPEARS CONDITIONAL UPON THE MAGNITUDE OF
DESTABILIZATION AND CONVECTIVE COVERAGE. AT THIS POINT...WILL NOT
INTRODUCE A 5 PERCENT HAIL PROBABILITY AREA DUE TO THE
CONDITIONALITY OF THE THREAT.

..BROYLES/COHEN.. 05/14/2012

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