Slight Risk - W & C Texas And S Texas Panhadle

[Paul Sherman]

Could be a good Chase day in V Nice Terrain around the Lubbock Area

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1237 AM CDT SAT APR 11 2009

VALID 111200Z - 121200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTN/TONIGHT ACROSS PARTS

OF THE SRN PLAINS....

...SYNOPSIS...

MODELS ARE FAIRLY SIMILAR CONCERNING THE EVOLUTION OF THE AMPLIFIED

TROUGH WITHIN THE SOUTHERN BRANCH OF SPLIT POLAR WESTERLIES NOW

MIGRATING ACROSS CALIFORNIA INTO THE GREAT BASIN AND SOUTHERN

PLATEAU. AS AN UPSTREAM NORTHERN BRANCH IMPULSE APPROACHES THE

BRITISH COLUMBIA/PACIFIC NORTHWEST COAST...THE LARGER SCALE TROUGH

IS PROGGED TO GRADUALLY DEVELOP EASTWARD ACROSS THE ROCKIES LATER

TODAY/TONIGHT. THIS IS EXPECTED TO OCCUR...AS AN EMBEDDED CLOSED

LOW LIFTS OUT OF THE LOWER COLORADO VALLEY THROUGH THE CENTRAL

ROCKIES AND WEAKENS...WHILE ANOTHER SHORT WAVE IMPULSE AND

ASSOCIATED JET STREAK DIG THROUGH THE NORTHWEST MEXICAN

PLATEAU...BEFORE TURNING EASTWARD ACROSS THE SOUTHERN ROCKIES/HIGH

PLAINS. A SECONDARY MID-LEVEL CIRCULATION MAY BEGIN TO FORM OVER

THE TEXAS SOUTH PLAINS BY EARLY SUNDAY.

MEANWHILE...THE DOWNSTREAM FLOW REGIME ACROSS THE REMAINDER OF THE

U.S. INTO THE WESTERN ATLANTIC WILL BEGIN TO SHARPEN...WITH A RIDGE

BUILDING THROUGH THE MISSISSIPPI VALLEY...AND A TROUGH DIGGING

SOUTHEAST OF THE UPPER GREAT LAKES REGION INTO AREAS OFF THE

NORTHERN/MID ATLANTIC COAST. THE WEAKENING REMNANTS OF THE COMPACT

BUT VIGOROUS CLOSED LOW...WHICH HAS CONTRIBUTED TO A WIDESPREAD

SEVERE WEATHER OUTBREAK FROM THE SOUTHERN PLAINS THROUGH THE MID

SOUTH AND SOUTHEAST STATES THE PAST COUPLE OF DAYS...IS EXPECTED TO

BE SHIFTING OFF THE MID ATLANTIC COAST EARLY IN THE PERIOD...BEFORE

ACCELERATING NORTHEASTWARD AHEAD OF THE DIGGING UPSTREAM TROUGH.

...SOUTHERN PLAINS...

IN THE WAKE OF AN EXPANSIVE COLD SURFACE RIDGE...RETREATING TO THE

EAST OF THE MISSISSIPPI VALLEY...MODELS INDICATE A WEAK LOW-LEVEL

MOISTURE RETURN TO THE VICINITY OF A DEVELOPING LEE SURFACE TROUGH

ACROSS PARTS OF WEST TEXAS INTO EASTERN NEW MEXICO TODAY. THIS IS

WHERE STRONGEST SURFACE HEATING IS EXPECTED...WHICH...COUPLED WITH

AT LEAST MODESTLY STEEP MID-LEVEL LAPSE RATES...MAY CONTRIBUTE TO

WEAK MIXED LAYER CAPE ON THE ORDER OF 500-750 J/KG. ASSOCIATED WITH

THE INITIAL CLOSED LOW LIFTING INTO THE CENTRAL ROCKIES...A 50-70 KT

SOUTH SOUTHWESTERLY...CYCLONIC 500 MB JET STREAK IS PROGGED TO NOSE

ACROSS EASTERN NEW MEXICO DURING AND SHORTLY AFTER THE PEAK HEATING

HOURS. THIS IS EXPECTED TO BE ACCOMPANIED BY WEAKENING INHIBITION

ABOVE THE HEATED BOUNDARY LAYER...WHICH SHOULD ALLOW FOR THE

INITIATION OF CONVECTIVE DEVELOPMENT BY LATE AFTERNOON. THIS MAY

INCLUDE A FEW SUPERCELLS WITH THE RISK FOR LARGE HAIL/DAMAGING WIND

GUSTS. WHILE LOW-LEVEL TEMPERATURE/DEW POINT SPREADS WITHIN THE

FAIRLY DEEPLY MIXED BOUNDARY LAYER MAY BE SOMEWHAT LARGE...SIZABLE

CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS COULD SUPPORT POTENTIAL FOR AT

LEAST BRIEF TORNADOES.

INTO THE EVENING HOURS...STRENGTHENING LOW LEVEL WARM

ADVECTION...FOLLOWED BY INCREASING MID/UPPER FORCING FOR UPWARD

VERTICAL MOTION ASSOCIATED WITH THE NEXT JET STREAK NOSING TOWARD

THE TEXAS BIG BEND REGION...IS EXPECTED TO BECOME FOCUSED ACROSS

WEST CENTRAL TEXAS. MODELS SUGGEST THAT THIS WILL OCCUR COINCIDENT

WITH A STRONGER INFLUX OF GULF MOISTURE...THOUGH THIS MAY BE ABOVE A

STABLE OR STABILIZING BOUNDARY LAYER. REGARDLESS...DESTABILIZATION

PROBABLY WILL BECOME SUFFICIENT TO SUPPORT AT LEAST A RISK FOR LARGE

HAIL WITHIN AN EVOLVING CONVECTIVE CLUSTER...WHICH IS EXPECTED TO

PERSIST AND SPREAD TOWARD NORTH CENTRAL/CENTRAL TEXAS OVERNIGHT.

...FLORIDA...

THE LARGE-SCALE PATTERN EVOLUTION IS PROGGED TO RESULT IN

STRENGTHENING NORTHWESTERLY MID/UPPER FLOW ACROSS THE FLORIDA

PENINSULA TODAY...CONTRIBUTING TO DEEP LAYER SHEAR FAVORABLE FOR

SIGNIFICANT MID-LEVEL UPDRAFT ROTATION. THIS SHOULD BE MOST

PRONOUNCED ALONG THE CENTRAL ATLANTIC COAST SEA BREEZE...WHERE

LOW-LEVEL CONVERGENCE IS EXPECTED TO BECOME MAXIMIZED. ALTHOUGH

WARM TEMPERATURES/SUBSIDENCE ALOFT...ASSOCIATED WITH A BUILDING HIGH

LEVEL RIDGE...WILL BE POTENTIAL LIMITING FACTORS TO CONVECTIVE

DEVELOPMENT...AN ISOLATED STRONG OR SEVERE STORM APPEARS POSSIBLE

DURING THE AFTERNOON HOURS.

[dogs32]

* Tornado Warning For...

Yoakum County In Northwest Texas.

* Until 515 PM CDT

* At 445 PM CDT...National Weather Service Doppler Radar Indicated A

Severe Thunderstorm Capable Of Producing A Tornado. The Most

Dangerous Part Of This Storm Was Located 8 Miles West Of Denver

City...Moving Northeast At 30 Mph.

* Some Locations Near The Path Of This Storm Include Highway 83 West

Of Denver City...And Eventually Plains