DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 131240
SWODY1
SPC AC 131237

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0637 AM CST FRI DEC 13 2013

VALID 131300Z - 141200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
IN MID-UPPER LEVELS...FLOW IS EXPECTED TO BECOME MORE CYCLONIC OVER
MOST OF CONUS THROUGH PERIOD...EXCEPT INVOF SYNOPTIC-SCALE RIDGING
THAT WILL DOMINATE PATTERN INVOF PAC COAST. MID-UPPER CYCLONE OVER
AZ/NM BORDER REGION IS LOSING AMPLITUDE AND BECOMING OPEN-WAVE
TROUGH ATTM. THIS PERTURBATION WILL MOVE EWD ACROSS PORTIONS NW TX
AND SWRN OK BY 00Z...THEN DEAMPLIFY AS IT EJECTS NEWD TO NEAR MOUTH
OF OH RIVER BY 12Z. MEANWHILE...PHASING OF INITIALLY SEPARATE
500-MB VORTICITY BANNERS NOW OVER NRN ID AND SIERRAS IS
FCST...LEADING TO SHORTWAVE TROUGHING OVER SRN NM AND FAR W TX BY
END OF PERIOD.

AT SFC...WEAK LOW NOW OVER SWRN KS IS EXPECTED TO MERGE TODAY WITH
BAROCLINIC ZONE INITIALLY TO ITS N...THEN MIGRATE SSEWD ACROSS TX
PANHANDLE...REACHING CDS AREA BY 00Z THEN MOVING ESEWD TO ARKLATEX
REGION BY 12Z. MEANWHILE...ATTACHED COLD FRONT SHOULD CROSS MOST OF
AR...OK AND TX.

...ARKLATEX REGION...
THUNDER SHOULD BE EPISODIC AND ISOLATED TO WIDELY SCATTERED...WITH
GREATEST COVERAGE THIS EVENING AND OVERNIGHT. VERY BRIEF/ISOLATED
LTG MAY OCCUR BEFORE THEN OVER PARTS OF CENTRAL/S TX...BUT ATTM
BUOYANCY MAGNITUDE/DEPTH DOES NOT FAVOR DENSE ENOUGH TSTM THREAT TO
EXTEND GEN THUNDER AREA THAT FAR SW.

LOW-LEVEL WAA AND MOISTURE TRANSPORT WILL BOOST THETAE IN AND NEAR
THIS REGION THROUGHOUT PERIOD AHEAD OF SFC LOW AND COLD FRONT...AND
THIS EVENING INVOF 50-60 KT SWLY LLJ. NEAR-SFC STABLE LAYER
INITIALLY ASSOCIATED WITH ANTECEDENT AND SLOWLY MODIFYING
CONTINENTAL/POLAR AIR MASS WILL BE SLOW TO ERODE...ESPECIALLY AFTER
DARK AS DIABATIC COOLING REINFORCES REMAINING STATIC STABILITY.
ISENTROPIC ASCENT TO LFC SHOULD CONTINUE AS EXISTING PRECIP PLUME
NOW OVER OK INTO CENTRAL/SW TX SHIFTS ENEWD ACROSS REGION...WHILE
LARGER INFLOW-LAYER THETAE OFFSETS WEAK MID-UPPER LAPSE RATES ENOUGH
TO YIELD 100-400 J/KG ELEVATED MUCAPE. FCST SOUNDINGS SUGGEST SOME
OF THAT BUOYANCY MAY EXTEND UPWARD INTO THERMAL LAYERS SUITABLE FOR
LTG GENERATION.

..EDWARDS/BOTHWELL.. 12/13/2013

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.