DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 142002
SWODY1
SPC AC 142000

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0200 PM CST FRI DEC 14 2012

VALID 142000Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE TX
PANHANDLE/NORTHWEST TX...

...TX PANHANDLE/NORTHWEST TX TO WESTERN OK/SOUTHWEST KS...
WHILE OVERALL FORECAST SCENARIO HAS NOT CHANGED DRAMATICALLY...HAVE
INTRODUCED A CATEGORICAL SLIGHT RISK /15 PERCENT WIND/ BASED ON
EARLY AFTERNOON OBSERVATIONAL TRENDS AND SHORT-TERM MODEL GUIDANCE.
AS OF MID-AFTERNOON...AN APPROX 150-MILE EAST-WEST WIDE CORRIDOR OF
CLEARING EXISTS PER VISIBLE SATELLITE IMAGERY TO THE IMMEDIATE EAST
OF A PACIFIC COLD FRONT...WITH THIS CLEARING COINCIDENT WITH A
CORRIDOR OF 4-5MB/2HR SURFACE PRESSURE FALLS.

WHILE MOISTURE/BUOYANCY WILL REMAIN MINIMAL...SUFFICIENT MOISTURE
SHOULD EXIST FOR THE MATURATION OF LOW-TOPPED TSTMS AND EVENTUAL
FAST-MOVING CONVECTIVE BANDS THROUGH LATE AFTERNOON IN THE PRESENCE
OF INCREASING FORCING FOR ASCENT AND ROBUST LOWER-MIDDLE
TROPOSPHERIC FLOW. THIS SCENARIO IS WELL-SUPPORTED BY VARIOUS
12Z-BASED HIGH-RES CONVECTION ALLOWING GUIDANCE. RECENT CANNON AFB
WSR-88D VWP DATA SAMPLES 50+ KT WINDS WITHIN THE LOWEST 1-3 KM. FOR
ADDITIONAL INFORMATION...SEE MESOSCALE DISCUSSION 2155.

..GUYER.. 12/14/2012

.PREV DISCUSSION... /ISSUED 1029 AM CST FRI DEC 14 2012/

...SYNOPSIS...
PATTERN WILL REMAIN PROGRESSIVE ACROSS THE LWR 48 THROUGH SAT...ON
NRN FRINGE OF ELONGATED UPR RIDGE EXTENDING FROM CNTRL MEXICO ENE
INTO THE GULF OF MEXICO/FL. POTENT SHORTWAVE TROUGH NOW OVER AZ
SHOULD ACCELERATE ENE INTO ERN NM BY EVE...AND INTO CNTRL IA/MO BY
12Z SAT...AS UPSTREAM IMPULSE AMPLIFIES SE TOWARD NRN BAJA CA.

AT THE SFC...LEE CYCLONE WILL CONSOLIDATE OVER SE CO LATER
TODAY...AND TRACK ENE ACROSS CNTRL/NRN KS TNGT/EARLY SAT. TRAILING
PACIFIC COLD FRONT SHOULD SURGE E ACROSS THE SRN HIGH PLNS THIS
AFTN/EARLY TNGT...WHERE IT WILL OVERTAKE LEE TROUGH/DEVELOPING DRY
LINE OVER FAR ERN NM/W TX NWD INTO SW KS.

...SRN HI PLNS ENE INTO PARTS OF KS/OK THIS AFTN INTO TNGT...
A BAND OF STRONG/DEEP FORCING FOR ASCENT /DCVA/ ON LEADING EDGE OF
EJECTING SHORTWAVE TROUGH WILL MOVE QUICKLY ENE ACROSS ERN NM/W TX
THIS AFTN...AND INTO THE TX/OK PANHANDLE REGION BY EVE...BEFORE
CONTINUING NE INTO KS AND NE OK EARLY SAT.

DEEP WIND PROFILES WITHIN THE ZONE OF ASCENT WILL BE QUITE FAVORABLE
FOR ORGANIZED SUSTAINED STORMS/SUPERCELLS...WITH 700 MB SWLY FLOW
INCREASING TO AOA 50 KTS AND 500 MB WIND SPEEDS ABOVE 80 KTS.
BUOYANCY ACROSS THE REGION WILL...HOWEVER...REMAIN VERY
LIMITED...DESPITE PRESENCE OF SIGNIFICANT MID LVL COLD ADVECTION
WITH UPR IMPULSE. BUOYANCY WILL BE LIMITED BOTH BY /1/ INSUFFICIENT
TIME FOR LOW LVL AIR MASS RECOVERY/GULF MOISTURE RETURN OVER THE SRN
PLNS...AND /2/ LIKELY PERSISTENCE OF SCTD AREAS OF RAIN WITHIN THE
NARROW AXIS OF MOISTURE RETURN /WITH SFC DEWPOINTS MID-UPR 40S/.
THIS RAINFALL IS BEING SUPPORTED BY PERSISTENT UPR DIVERGENCE WELL
AHEAD OF THE AZ UPR TROUGH...AND WILL MAINTAIN LOW LVL CLOUD COVER
ACROSS MOST OF TX THAT WILL HINDER SFC HEATING/STEEPENING OF LOW LVL
LAPSE RATES.

NEVERTHELESS...GIVEN STRENGTH OF DEEP FORCING FOR ASCENT...AND
PRESENCE OF MERGING COLD FRONT/LEE TROUGH TO FOCUS LOW LVL
UPLIFT...EXPECT A LINE OF FORCED...LOW-TOPPED SHOWERS/STORMS WILL
FORM IN NARROW ZONE OF PARTLY CLEAR SKIES OVER ERN NM BY EARLY AFTN.
THIS ACTIVITY SHOULD SUBSEQUENTLY SWEEP ENE INTO W TX AND THE TX/OK
PANHANDLE REGION BY EVE...ACCOMPANIED BY A RISK FOR SPORADIC STRONG
TO POSSIBLY BRIEFLY SVR WIND GUSTS...AND POSSIBLY MARGINALLY SVR
HAIL. A TORNADO ALSO CANNOT BE ENTIRELY RULED OUT. THE CONVECTION
SHOULD WEAKEN BY LATER TNGT AS THE BAND OF STRONGEST/DEEPEST ASCENT
CONTINUES RAPIDLY NEWD BEYOND AXIS OF GREATEST SFC-BASED
INSTABILITY.

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