DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 141628
SWODY1
SPC AC 141626

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1126 AM CDT WED AUG 14 2013

VALID 141630Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EARLY
EVENING ACROSS PARTS OF SOUTH CENTRAL INTO SOUTHEAST TEXAS...

...SYNOPSIS...
THE VIGOROUS SHORT WAVE TROUGH NOW TURNING EAST OF THE LOWER GREAT
LAKES REGION APPEARS LIKELY TO SHIFT ACROSS NEW ENGLAND INTO THE
CANADIAN MARITIMES THROUGH THE REMAINDER OF THIS FORECAST
PERIOD...AS ANOTHER STRONG IMPULSE DIGS SOUTH OF HUDSON BAY. AS
THIS OCCURS...MODELS SUGGEST MID/UPPER FLOW EAST OF THE ROCKIES WILL
BECOME A BIT LESS AMPLIFIED...BUT IT MAY REMAIN AT LEAST MODESTLY
STRONG AND CYCLONIC IN A COUPLE OF BELTS...THE MORE PROMINENT ONE
ACROSS THE UPPER MIDWEST AND GREAT LAKES THROUGH THE NORTHEAST...THE
OTHER EAST OF THE CENTRAL ROCKIES THROUGH THE SOUTHEAST.
MEANWHILE...TO THE NORTH OF A SUPPRESSED SUBTROPICAL HIGH CENTER
OVER NORTHERN MEXICO...UPPER RIDGING WILL BE MAINTAINED ALONG AN
AXIS NORTHWARD ACROSS THE INTERMOUNTAIN REGION THROUGH THE NORTHERN
ROCKIES...WHILE A COUPLE OF WEAK IMPULSES PROGRESS AROUND ITS
NORTHEASTERN PERIPHERY...ACROSS PARTS OF THE NORTHERN AND CENTRAL
PLAINS. FARTHER WEST...CYCLONIC FLOW WILL PERSIST ACROSS THE
PACIFIC NORTHWEST...AROUND THE EASTERN PERIPHERY OF AN OFFSHORE LOW.

IN RESPONSE TO THESE DEVELOPMENTS...THE FRONTAL ZONE...ASSOCIATED
WITH A SIGNIFICANT COLD INTRUSION TO THE LEE OF THE ROCKIES...IS
EXPECTED TO GENERALLY STALL/WEAKEN OVER THE SOUTHERN TIER STATES
TODAY. ANOTHER REMNANT LOW-LEVEL BAROCLINIC ZONE...CONVECTIVELY
REINFORCED IN SOME LOCATIONS...WILL LINGER ACROSS PARTS OF THE
NORTHERN AND CENTRAL PLAINS...WHILE WARM AND DEEPLY MIXED AIR FROM
THE PLATEAU REGION BEGINS TO SLOWLY ADVECT EAST OF THE CENTRAL
ROCKIES.

LINGERING STRONGER DEEP LAYER MEAN FLOW FIELDS AND SHEAR ACROSS THE
EAST WILL REMAIN DISPLACED TO THE NORTH OF PRE-FRONTAL BOUNDARY
LAYER MOISTURE AND INSTABILITY...WHICH IS BECOMING CONFINED TO PARTS
OF THE EASTERN GULF STATES AND THE FLORIDA PENINSULA. AT THE SAME
TIME...FARTHER WEST...ASIDE FROM PERHAPS A FEW LOCALIZED POCKETS
ACROSS THE CENTRAL AND NORTHERN HIGH PLAINS...THE DEVELOPMENT OF
SIZABLE CAPE WILL BE CONFINED TO THE FRONTAL ZONE ACROSS PARTS OF
CENTRAL AND SOUTHEAST TEXAS...WITH SHEAR AND DEEP LAYER MEAN FLOW
FIELDS REMAINING WEAK ACROSS MUCH OF THE PLAINS. AS SEASONABLY DRY
AND STABLE CONDITIONS PERSIST ACROSS MUCH OF THE WEST...WITH THE
POSSIBLE EXCEPTION OF THE SOUTHERN ROCKIES AND ADJACENT SOUTHERN
PLATEAU...SEVERE THUNDERSTORM POTENTIAL ACROSS MUCH OF THE NATION
APPEARS RELATIVELY LOW TODAY.

...TEXAS...
IT DOES APPEAR THAT STRONG SURFACE HEATING WILL CONTRIBUTE TO A HOT
AND DEEPLY MIXED BOUNDARY LAYER...WITHIN AT LEAST A NARROW CORRIDOR
ALONG WHICH MOISTURE WILL BE SUPPORTIVE OF MODESTLY LARGE
CAPE...ROUGHLY FROM THE EDWARDS PLATEAU/HILL COUNTRY TOWARD THE
MID/UPPER TEXAS COASTAL PLAIN. THIS ENVIRONMENT PROBABLY WILL BE
CONDUCIVE TO STRONG DOWNBURSTS WITH THUNDERSTORMS EXPECTED TO FORM
DURING THE MID TO LATE AFTERNOON HOURS...IN THE PRESENCE OF
RELATIVELY WEAK INHIBITION. FORCING ASSOCIATED WITH A WEAK IMPULSE
MIGRATING EAST SOUTHEAST OF THE HIGH PLAINS MAY AID
DEVELOPMENT...WITH SOME CONSOLIDATION OF ACTIVITY AND ASSOCIATED
COLD POOLS...WHICH SHOULD TEND TO PROPAGATE SOUTHEASTWARD/SOUTHWARD
THROUGH EARLY EVENING.

..KERR/COHEN.. 08/14/2013

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