DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 291257
SWODY1
SPC AC 291255

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT TUE OCT 29 2013

VALID 291300Z - 301200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MAJOR MID-UPPER LEVEL FACTOR IN OUTLOOK WILL BE SYNOPTIC-SCALE
CYCLONE...ITS CENTER NOW DRIFTING ERRATICALLY OVER NERN NV WHILE
ORBITED BY SEVERAL MESOSCALE VORTICITY MAXIMA/SHORTWAVE
PERTURBATIONS. ASSOCIATED TROUGH WILL MAINTAIN NET POSITIVE TILT
WHILE ONE OF THOSE SHORTWAVE TROUGHS -- NOW EVIDENT IN MOISTURE
CHANNEL IMAGERY OVER SRN UT -- EJECTS NEWD TO NRN WY BY 00Z. LATTER
FEATURE MAY BECOME PRIMARY 500-MB LOW FOR BROADER CYCLONE
OVERNIGHT...AS IT CROSSES MT/WY BORDER. MEANWHILE...INITIAL
CIRCULATION CENTER SHOULD FOLLOW CURVING SWD/SEWD PATH ACROSS
NV...BECOMING OPEN-WAVE SHORTWAVE TROUGH THIS EVENING AND REACHING
LAS/EED/IGM AREA DURING 09Z-12Z TIME FRAME.

AT SFC...WEAK LOW NOW EVIDENT ALONG FRONTAL ZONE OVER SWRN KS...NEAR
ITS INTERSECTION WITH OUTFLOW BOUNDARY FROM ONGOING MCS...SHOULD
MOVE SLOWLY NEWD ACROSS CENTRAL KS. MEANWHILE...SECONDARY/WEAK LOW
WITHOUT SUBSTANTIAL CYCLONIC FLOW MAY DEVELOP WHERE FRONT AND LEE
TROUGH WILL INTERSECT THIS EVENING...OVER NERN NM. AS THESE
PROCESSES OCCUR...STG FRONT NOW EVIDENT OVER SWRN KS...NWRN
OK...CENTRAL/SRN TX PANHANDLE...AND NERN NM SHOULD RETREAT
NWD...SLOWLY AT FIRST THEN SOMEWHAT FASTER OVERNIGHT TO MEET
DEVELOPING FRONTAL-WAVE LOW OVER SERN CO.

HEIGHT FALLS ALOFT...ASSOCIATED WITH SHORTWAVE PROCESSES REVOLVING
AROUND WRN CONUS MID-UPPER CYCLONE...SHOULD STAY AWAY FROM DRYLINE
REGION THROUGH MOST...IF NOT ALL...OF DAYLIGHT HOURS. HEIGHT FALLS
THEN SHOULD SPREAD OVER CENTRAL/SRN HIGH PLAINS AFTER
DARK...ESPECIALLY AFTER 06Z...WHEN MOIST SECTOR BACKS NWWD AMIDST
PERSISTENT LOW-LEVEL PRESSURE FALLS AND LATE-PERIOD SFC
CYCLOGENESIS.

...CENTRAL/SRN PLAINS...
CONDITIONAL POTENTIAL REMAINS FOR DIURNAL/SFC-BASED TSTM DEVELOPMENT
FROM FRONTAL ZONE SWD TO SW TX AND ADJOINING NRN COAHUILA.
ENVIRONMENT WILL BE CHARACTERIZED BY FAVORABLE PW/DEW POINTS AND
DEEP SHEAR FOR SVR. HOWEVER...WHILE SEVERE-STORM DEVELOPMENT IS
STILL POSSIBLE FROM LATE AFTN INTO EVENING ALONG/AHEAD OF
DRYLINE...SOME SYNOPTIC TO MESOSCALE FACTORS ARE APPARENT THAT NOW
MAKE RISK TOO ISOLATED AND UNCERTAIN TO MAINTAIN UNCONDITIONAL HAIL
PROBABILITIES AT CATEGORICAL CRITERIA.

ABUNDANT HIGH-CLOUD COVER -- PARTLY EMANATING FROM LAST FEW DAYS OF
UPPER-LEVEL OUTFLOW FROM ERN PAC TS RAYMOND -- WILL STUNT INSOLATION
AND MAKE SFC HEATING ERRATIC...SLOW AND PATCHY ACROSS THIS REGION.
12Z AMA/MAF RAOBS AND FCST SOUNDINGS SAMPLE MDT EML-RELATED WARM
NOSE THAT WILL HELP TO MAINTAIN MLCINH THROUGH MUCH OF PERIOD.
ALSO...MOST PROGS REASONABLY INDICATE ONLY WEAK CONVERGENCE...AT
MOST...ALONG DRYLINE THROUGH EARLY EVENING...FOLLOWING SHORT PERIOD
OF AFTN VEERING RELATED TO NEWD-MOVING KS SFC LOW. CONVERGENCE
WOULD BE CRUCIAL TO SUPPORTING DRYLINE/FRONTAL DEVELOPMENT GIVEN
MUTING OF SOLENOIDAL FORCING RELATED TO AFOREMENTIONED LACK OF
EITHER ABSOLUTE OR DIFFERENTIAL HEATING. OROGRAPHIC LIFT OVER
SERRANIAS DEL BURRO OR NEARBY TX BIG BEND MTNS MAY OFFER MOST
PREDICTABLE SOURCE OF LIFT FOR CONVECTION BEFORE ABOUT 03Z.

OTHER ISOLATED TO WIDELY SCATTERED DEVELOPMENT MAY OCCUR OVERNIGHT
JUST ABOUT ANYWHERE OVER BROAD SWATH OF WARM SECTOR...AMIDST BROAD
WAA/MOISTURE-TRANSPORT REGIME. NEAR-SFC AIR MASS AFTER DARK WILL BE
CHARACTERIZED BY DIABATIC COOLING...PATCHES OF STRATUS/PRECIP...AND
RELATED POOR LAPSE RATES. HOWEVER...FCST SOUNDINGS SHOW EFFECTIVELY
SFC-BASED PARCELS MAY BE POSSIBLE OVER THOSE PARTS OF OK AND SWRN
THROUGH NWRN TX WHERE UPPER-60S SFC DEW POINTS CAN OCCUR...WHILE LLJ
ENLARGES HODOGRAPHS. AS SUCH...HAVE ADDED MRGL/SUB-CATEGORICAL
TORNADO PROBABILITIES.

ANY OROGRAPHICALLY RELATED TSTMS MOVING NEWD FROM MEX OR SW TX MAY
EXPAND INTO STRENGTHENING LLJ AND OFFER MRGL HAIL POTENTIAL. TSTMS
ALSO MAY DEVELOP OVERNIGHT IN LOW-LEVEL FRONTOGENETIC REGIME NEAR
CENTRAL HIGH PLAINS LOW...AS WELL AS WHERE ISENTROPIC LIFT BOOSTS
PARCELS TO LFC WITHIN BROAD LLJ OVER N TX AND/OR OK. ANY CONVECTION
THAT DOES FORM WILL POSE RISK OF ISOLATED HAIL.

..EDWARDS/COHEN.. 10/29/2013

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