ACUS03 KWNS 190721
SWODY3
SPC AC 190719
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0219 AM CDT SUN OCT 19 2008
VALID 211200Z - 221200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
AMPLIFICATION OF THE UPPER PATTERN IS FORECAST THIS PERIOD...AS AN
UPPER LOW DEEPENS AS IT SHIFTS ACROSS THE LOWER GREAT LAKES/NEW
ENGLAND AND A SECOND TROUGH -- INITIALLY CROSSING THE ROCKIES --
EXPANDS AS IT MOVES INTO THE CENTRAL CONUS. MEANWHILE...THE
DOWNSTREAM RIDGE WILL ALSO AMPLIFY ALONG THE W COAST AHEAD OF A
STRENGTHENING NERN PACIFIC TROUGH.
AT THE SURFACE...A COLD FRONT SHOULD CONTINUE ACROSS THE NORTHEAST
-- AND EVENTUALLY MOVE OFFSHORE. MEANWHILE...WEAK CYCLOGENESIS MAY
OCCUR INVOF THE CENTRAL/SRN PLAINS ALONG THE TRAILING PORTION OF
THIS FRONT...AS THE AFOREMENTIONED UPPER TROUGH EXPANDS/DEEPENS INTO
THE PLAINS.
...PARTS OF THE CENTRAL AND SRN HIGH PLAINS INTO SRN KS/NRN OK...
MODELS FORECAST -- TO VARYING DEGREES -- CYCLOGENESIS ALONG THE
BAROCLINIC ZONE FORECAST TO BE LINGERING OVER THE HIGH PLAINS EARLY
IN THE PERIOD. THE LOW SHOULD BEGIN TO STRENGTHEN A BIT THROUGH THE
AFTERNOON AND INTO THE EVENING..AS SHORT-WAVE ENERGY DIGS SEWD
ACROSS THE HIGH PLAINS WITHIN THE DEEPENING/LARGER-SCALE UPPER
TROUGH MOVING INTO THE PLAINS.
MODELS DIFFER WITH RESPECT THE STRENGTH OF THIS FEATURE...BUT ALL
AGREE THAT A WEAK CYCLONE SHOULD LIE SOMEWHERE WITHIN AN ENVELOPE
FROM ERN CO INTO THE TX PANHANDLE...WITH THE BAROCLINIC ZONE --
EFFECTIVELY BECOMING A WEAK WARM FRONT -- LYING NNW-SSE ACROSS THE
NRN OK VICINITY.
INSTABILITY WILL REMAIN LIMITED /GENERALLY AOB 500 J/KG MIXED-LAYER
CAPE/ WITHIN THE WEAK/DEVELOPING WARM SECTOR...BUT LIKELY SUFFICIENT
-- GIVEN DEGREE OF UVV ANTICIPATED -- TO ALLOW STORM DEVELOPMENT BY
LATE AFTERNOON.
MID-LEVEL FLOW WILL NOT BE EXCESSIVE -- LIKELY NO MORE THAN 30 TO 40
KT. HOWEVER...WITH SLYS/SSELYS WITHIN THE WARM-SECTOR BOUNDARY
LAYER VEERING TO WLY AT MID LEVELS...SHEAR SUPPORTIVE OF ROTATING
STORMS IS FORECAST. ALONG WITH A POTENTIAL FOR HAIL/WIND WITH A FEW
STRONGER STORMS...THE PRESENCE OF THE SURFACE LOW AND WARM
FRONT...LOW LCLS...AND AMPLE LOW-LEVEL SHEAR ALSO SEEMS TO SUPPORT
SOME THREAT FOR A TORNADO OR TWO. ATTM...WILL INTRODUCE LOW SEVERE
PROBABILITY...BUT AREA COULD REQUIRE A SLIGHT RISK UPGRADE IN LATER
FORECASTS.
..GOSS.. 10/19/2008
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