SWODY1
SPC AC 130559
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT SAT OCT 13 2007
VALID 131200Z - 141200Z
..THERE IS A SLGT RISK OF SVR TSTMS OVER THE HIGH PLAINS AND
ADJACENT CNTRL PLAINS...
..SYNOPSIS...
MODERATELY AMPLIFIED FLOW REGIME WILL BECOME MORE PROGRESSIVE THIS
PERIOD AS STRONG UPPER LOW SWINGS ACROSS PARTS OF NRN NEW ENGLAND
AND LARGER BUT NO LESS INTENSE TROUGH/LOW SYSTEM MOVES FROM THE FOUR
CORNERS TO THE CNTRL PLAINS. WRN/CNTRL U.S. SYSTEM WILL BE QUITE
DYNAMIC AS 60-75KT CYCLONICALLY CURVED MID LEVEL WIND MAX EMERGES
OUT ACROSS THE SRN/CNTRL HIGH PLAINS LATE TODAY ACCOMPANIED BY 12H
500MB HEIGHT FALLS OF 60-90M. RESULTING SURFACE CYCLONE WILL
CONSOLIDATE ACROSS ERN CO/WRN KS THROUGH LATE TODAY AND TRACK ONLY
SLOWLY NEWD TO NWRN KS THROUGH SUNDAY MORNING. GIVEN STRENGTHENING
DEEP-LAYER SWLY FLOW TRANSLATING THROUGH THE BASE OF THE
TROUGH...DRYLINE SHOULD MIX EWD/NEWD ACROSS THE SRN HIGH PLAINS AND
ARC FROM WEST TX TO TX PNHDL THEN BACK NWD/NWWD TO THE LOW NEAR
CO/KS BORDER. WARM FRONT WILL START OUT THE DAY OVER KS WHERE SMALL
MCS MAY BE ONGOING ACROSS ERN KS/MO. IN THE WAKE OF THIS SYSTEM AND
IN RESPONSE TO MASS ADJUSTMENT AHEAD OF THE UPPER TROUGH AND
SUBSEQUENT LEE-SIDE CYCLOGENESIS...FRONT IS EXPECTED TO RETREAT NWD
THROUGH THE PERIOD TO A POSITION NEAR THE KS/NEB BORDER BY TONIGHT.
..SRN HIGH PLAINS TO CNTRL PLAINS...
RELATIVELY UNPERTURBED MOIST AXIS CHARACTERIZED BY 8-12C DEWPOINT
PLUME AT 850MB AND NEAR 60F SURFACE DEWPOINTS WILL BE SITUATED
ACROSS THE SRN AND CNTRL HIGH PLAINS. DIURNAL HEATING AND STEEPENING
LAPSE RATES WILL CONTRIBUTE TO MODEST DESTABILIZATION IN A CORRIDOR
FROM WEST TX TO WRN KS WITH MLCAPE OF 1000-1500 J/KG POSSIBLE BY
LATE AFTERNOON. DESPITE MIXING ALONG THE DRYLINE AND INCREASING
LARGE SCALE LIFT/QG-FORCING WITH APPROACHING UPPER
TROUGH...CONVECTIVE INITIATION WITHIN THIS CORRIDOR WILL BE
INHIBITED BY RELATIVELY WARM TEMPERATURES ALOFT AND LACK OF GREATER
LOW LEVEL MOISTURE. ALMOST ALL THE LATEST AVAILABLE GUIDANCE
INDICATES A VERY LOW PROBABILITY FOR STORM INITIATION FROM TX NWD
ACROSS MOST OF WRN KS THROUGH THIS EVENING. HOWEVER...DESPITE THESE
SIGNALS...PATTERN RECOGNITION AND MAGNITUDE AND TIMING OF FORCING
FOR ASCENT EMERGING ACROSS THE HIGH PLAINS ALL POINT TO A
CONDITIONAL POTENTIAL FOR ISOLATED SUPERCELL STORMS INITIATING NEAR
THE DRYLINE BEFORE SUNSET. THIS POTENTIAL WARRANTS AT LEAST LOW
HAIL/WIND PROBABILITIES...INCREASING IN MAGNITUDE WITH NWD EXTENT.
FARTHER NORTH...FROM NEAR THE SURFACE LOW/DRYLINE/WARM FRONT OVER
ERN CO/WCNTRL TO NWRN KS...AND EWD ALONG AND NORTH OF THE WARM FRONT
OVER NEB...ROBUST TSTM DEVELOPMENT APPEARS MORE LIKELY FROM LATE
AFTERNOON INTO SATURDAY NIGHT. VERY STRONG SHEAR AND FORCING WILL
COINCIDE WITH LOW LEVEL FOCUSED ASCENT AND PRONOUNCED LOW LEVEL SRH
NEAR THE LOW AND FRONT. THIS ENVIRONMENT SHOULD SUPPORT SUPERCELLS
WITH THE POTENTIAL FOR STRONG LOW LEVEL MESOCYCLONES AND PERHAPS A
TORNADO OR TWO...IN ADDITION TO LARGE HAIL...IF DISCRETE
SURFACE-BASED CONVECTION CAN INITIATE WITHIN RELATIVELY NARROW WARM
SECTOR. OTHERWISE...STRENGTH OF SLOPED ASCENT AND EFFECTIVE SHEAR OF
40-50KT ACROSS THE WARM FRONT WILL BE MORE THAN SUFFICIENT FOR
NUMEROUS ROTATING STORMS CAPABLE OF PRODUCING LARGE HAIL AND LOCALLY
STRONG TO DAMAGING WIND GUSTS. THIS POTENTIAL MAY PERSIST ACROSS
PARTS OF NEB WELL INTO THE NIGHT AS LOW LEVEL JET MAINTAINS MASS
INFLOW AND UPPER TROUGH PROVIDES LARGE SCALE ASCENT.
.CARBIN/JEWELL.. 10/13/2007
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment