SPC: Moderate Risk, TX
Posted: Thu May 23, 2013 2:28 pm
Yet another one. Small area though. Hopefully will be a bust.
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1120 AM CDT THU MAY 23 2013
VALID 231630Z - 241200Z
...THERE IS A MDT RISK OF SVR TSTMS LATE THIS AFTN AND EVE ACROSS
PARTS OF THE EASTERN TEXAS PANHANDLE AND NORTHWEST TEXAS...
...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
AREA ACROSS THE SOUTHERN PLAINS AND RED RIVER VALLEY REGION...
...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS PARTS OF THE MID
ATLANTIC STATES INTO NEW ENGLAND...
...SYNOPSIS...
WHILE THE CURRENT BLOCKING PATTERN OVER NORTH AMERICA IS EXPECTED TO
BECOME A BIT LESS PROMINENT...LARGE-SCALE MID/UPPER FLOW OVER THE
U.S. IS EXPECTED TO REMAIN AMPLIFIED AND SLOW TO CHANGE. IN THE
EAST...THE TRANSITION OF A CLOSED LOW TO AN OPEN WAVE TROUGH
CONTINUES ACROSS THE GREAT LAKES AND LOWER OHIO VALLEY REGION...TO
THE SOUTH OF A SHORT WAVE TROUGH SLOWLY DIGGING SOUTHEAST OF THE
HUDSON/JAMES BAY REGION. BOTH THESE FEATURES WILL CONTINUE TO
GRADUALLY TURN EASTWARD/SOUTHEASTWARD TOWARD THE ATLANTIC SEABOARD
LATER TODAY AND TONIGHT. AT THE SAME TIME...A DEEP MID-LEVEL CLOSED
LOW WILL LINGER OVER THE PACIFIC NORTHWEST...WITH BROADER SCALE
UPPER TROUGHING ENCOMPASSING MUCH OF THE PACIFIC COAST STATES INTO
THE ROCKIES. A SIGNIFICANT MID-LEVEL IMPULSE IS EXPECTED TO
CONTINUE TO GRADUALLY PIVOT AROUND THE LOW...ACROSS THE NORTHERN
GREAT BASIN INTO THE NORTHERN ROCKIES BY LATE TONIGHT. THIS WILL
SUPPRESS MID-LEVEL HEIGHT RISES ACROSS PARTS OF THE NORTHERN
PLAINS...WHILE MID/UPPER RIDGING REMAINS OR BECOME MORE PROMINENT
ACROSS MUCH OF THE PLAINS INTO THE MISSISSIPPI VALLEY REGION. A
COUPLE OF WEAK IMPULSES PROGRESSING THROUGH THE CYCLONIC FLOW ACROSS
THE SOUTHERN PLATEAU INTO THE SOUTHERN ROCKIES REGION MAY HAVE AT
LEAST A GLANCING IMPACT ON PARTS OF THE SOUTHERN PLAINS...HOWEVER.
...MID ATLANTIC STATES INTO THE NORTHEAST...
AHEAD/EAST OF A COLD FRONT ADVANCING ACROSS THE LOWER GREAT LAKES
AND OHIO VALLEY REGION...MID-LEVEL LAPSE RATES APPEAR TO HAVE
STABILIZED CONSIDERABLY OVER THE PAST COUPLE OF DAYS. CONSIDERABLE
CLOUD COVER AND PRECIPITATION...SOME CONVECTIVE...IS ALREADY WELL
UNDERWAY...AND IT IS NOT CLEAR HOW MUCH DESTABILIZATION WILL TAKE
PLACE TODAY. THERE ARE BREAKS IN CLOUD COVER...WHICH WILL ALLOW FOR
AT LEAST POCKETS OF HEATING AND WEAK TO MODEST DESTABILIZATION...THE
STRONGEST OF WHICH SEEMS LIKELY TO TAKE PLACE ALONG THE LEE SURFACE
TROUGH...EAST OF THE APPALACHIANS. THIS MAY INCLUDE THE URBAN
CORRIDOR FROM WASHINGTON D.C./BALTIMORE INTO THE PHILADELPHIA AREA.
WHERE SUBSTANTIVE DESTABILIZATION IS ABLE TO TAKE PLACE...SHEAR AND
MOMENTUM ASSOCIATED WITH 20-40 KT SOUTHWESTERLY LOWER/MID
TROPOSPHERIC FLOW MAY ENHANCE CONVECTIVE DEVELOPMENT... CONTRIBUTING
TO STORM MOTION AND ORGANIZATION. STRONGEST ACTIVITY MAY BE CAPABLE
OF PRODUCING SEVERE WIND GUSTS...WITH SOMEWHAT LOWER POTENTIAL FOR
SEVERE HAIL OR A TORNADO.
...SOUTHERN PLAINS...
THE SEVERE STORM/SMALL STORM CLUSTER THAT EVOLVED FROM A LARGER
SCALE WARM ADVECTION REGIME OVER CENTRAL OKLAHOMA EARLIER THIS
MORNING IS CURRENTLY WEAKENING SOUTH OF THE RED RIVER...ACROSS PARTS
OF NORTHEAST TEXAS. IT MAY NOT BE OUT OF THE QUESTION THAT REMNANTS
OF THIS ACTIVITY COULD BE ASSOCIATED WITH NEW INTENSE STORM
DEVELOPMENT ACROSS PARTS OF EASTERN TEXAS INTO LOUISIANA LATER
TODAY...IN THE PRESENCE OF POTENTIALLY STRONG INSTABILITY.
HOWEVER...THE PRIMARY CONVECTIVE POTENTIAL IS EXPECTED TO BECOME
FOCUSED NEAR THE DRYLINE AND A DEVELOPING WARM FRONT ACROSS THE
SOUTHERN HIGH PLAINS LATER THIS AFTERNOON AND EVENING.
DESPITE THE TENDENCY FOR CONTINUING WEAK MID-LEVEL HEIGHT RISES
ACROSS THE SOUTHERN PLAINS TODAY...MODELS SUGGEST CONVECTIVE
INHIBITION WILL WEAKEN SUFFICIENTLY BY PEAK AFTERNOON HEATING FOR
STORM INITIATION ON THE DRYLINE. THE MOST INTENSE STORMS/GREATEST
STORM COVERAGE IS EXPECTED NEAR THE DRYLINE/WARM FRONT
INTERSECTION...EAST/SOUTHEAST OF LUBBOCK AND AMARILLO INTO AREAS OF
NORTHWEST TEXAS NEAR/SOUTH OF CHILDRESS. THIS IS WHERE
THERMODYNAMIC PROFILES WITH VERY STEEP MID-LEVEL LAPSE RATES AND
LARGE CAPE SHOULD BE SUPPORTIVE OF SUPERCELLS...BEFORE CONSIDERABLE
UPSCALE GROWTH OCCURS BY EARLY EVENING.
VERY LARGE HAIL IS POSSIBLE IN STRONGEST CELLS. A COUPLE OF
TORNADOES ARE ALSO POSSIBLE...BUT TORNADIC POTENTIAL MAY BE HINDERED
BY WEAKNESS IN MID-LEVEL FLOW...AND A TENDENCY FOR STORMS TO QUICKLY
GENERATE CONSIDERABLE OUTFLOW.
...NORTHERN ROCKIES...
ALTHOUGH MOISTURE APPEARS TO REMAIN LIMITED ACROSS THE BASINS
WEST/SOUTH OF THE LARAMIE AND BIG HORN MOUNTAINS OF WYOMING... THE
ENVIRONMENT APPEARS AT LEAST MARGINALLY CONDUCIVE TO ISOLATED
SUPERCELL DEVELOPMENT LATE THIS AFTERNOON/EVENING...SOME OF WHICH
COULD DEVELOP/SPREAD NORTH/EAST OF THE MOUNTAINS INTO PARTS OF
EASTERN WYOMING AND MONTANA.
..KERR/BUNTING.. 05/23/2013