DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 191251
SWODY1
SPC AC 191250

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0650 AM CST WED FEB 19 2014

VALID 191300Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON THROUGH
THIS EVENING OVER PARTS OF NERN OK...SERN KS AND WRN MO...

...SYNOPSIS...

THE PRIMARY FEATURE OF INTEREST THIS PERIOD IS A SHORT-WAVE TROUGH
WHICH WILL UNDERGO CONSIDERABLE AMPLIFICATION WHILE PROGRESSING FROM
THE PACIFIC NW AND GREAT BASIN TO THE GREAT PLAINS BY 20/12Z. THIS
SYSTEM WILL BE ATTENDED BY 100+ KT MID TO UPPER-LEVEL WIND MAXIMA
WHICH WILL INITIALLY ADVANCE EQUATORWARD FROM THE FAR NERN PACIFIC
BEFORE ROUNDING THE TROUGH BASE OVER THE SRN HIGH PLAINS LATE
TONIGHT INTO EARLY THURSDAY.

IN THE LOW LEVELS...12Z SURFACE ANALYSIS REVEALED A COLD FRONT
STRETCHING FROM A CYCLONE OVER CNTRL ONTARIO SWD INTO THE OH VALLEY
BEFORE CURVING SWWD TO LOW PRESSURE OVER SERN NM. FARTHER TO THE
NW...A PACIFIC FRONT EXTENDED FROM LOW PRESSURE OVER SWRN
SASKATCHEWAN SWWD TO NRN CA...WHILE A N-S-ORIENTED LEE TROUGH WAS
OBSERVED OVER THE NRN AND CNTRL HIGH PLAINS.

LEE CYCLOGENESIS IS FORECAST OVER THE CNTRL HIGH PLAINS TODAY WHICH
WILL PROMOTE THE NWD ADVANCEMENT OF THE SURFACE FRONT NOW ALONG THE
RED RIVER INTO THE OZARK PLATEAU...AND THE SEWD ACCELERATION OF THE
PACIFIC/COLD FRONT THROUGH THE NRN AND CNTRL HIGH PLAINS. BY 20/12Z
THE CO LEE CYCLONE IS EXPECTED TO BE LOCATED ALONG THE KS-MO BORDER
WITH THE COLD FRONT TRAILING SWWD INTO W-CNTRL TX...AND THE WARM
FRONT EXTENDING FROM THE LOW INTO THE OH VALLEY.

...CNTRL/SRN PLAINS INTO OZARKS LATE THIS AFTERNOON THROUGH
TONIGHT...

THE ATMOSPHERIC RESPONSE TO THE APPROACHING WRN U.S. TROUGH WILL
PROMOTE LEE CYCLONE DEVELOPMENT OVER THE CNTRL HIGH PLAINS...ALONG
WITH THE FORMATION OF A SLY LLJ ACROSS LOWER ELEVATIONS OF THE GREAT
PLAINS LATER TODAY INTO NIGHT. THESE PROCESSES WILL ENHANCE THE NWD
TRANSPORT OF AN INCREASINGLY MOIST AIR MASS WITHIN THE EXPANDING
WARM SECTOR WITH BOUNDARY LAYER DEWPOINTS RISING INTO THE 50S TO
AROUND 60 F. THIS MOISTENING WILL OFFSET ONLY MODEST DAYTIME HEATING
TO SUPPORT AFTERNOON MLCAPE VALUES APPROACHING 500-1000 J/KG.

LATEST MODEL GUIDANCE SUGGESTS THAT THE WARM SECTOR WILL REMAIN
CAPPED TO SURFACE-BASED INITIATION WITH ELEVATED TSTMS BECOMING
INCREASINGLY POSSIBLE BETWEEN 21-00Z NORTH OF THE WARM FRONT OVER
N-CNTRL/NERN OK INTO SERN KS. HERE...STRENGTHENING WAA ALONG THE
EVOLVING LLJ WILL BE AUGMENTED BY DCVA ATTENDANT TO A LOW-AMPLITUDE
SHORT-WAVE TROUGH EMERGING FROM THE SRN ROCKIES. THE PRIMARY HAZARD
APPEARS TO BE SEVERE HAIL GIVEN THE PRESENCE OF RELATIVELY COOL
MIDLEVEL TEMPERATURE PROFILES AND STRONG CLOUD-BEARING SHEAR.

EXPECT TSTMS TO INCREASE IN AREAL COVERAGE OVERNIGHT FROM ERN KS EWD
TOWARD THE MID MS VALLEY ALONG A STRENGTHENING/BROADENING NOCTURNAL
LLJ. ISOLATED OCCURRENCES OF HAIL APPROACHING SEVERE LEVELS WILL
REMAIN POSSIBLE WITH THE MOST INTENSE STORMS.

..MEAD/SMITH.. 02/19/2014

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