Friday, September 4, 2009

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 050102
SWODY1
SPC AC 050059

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0759 PM CDT FRI SEP 04 2009

VALID 050100Z - 051200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
UPPER AIR PATTERN CONTINUED TO FEATURE MEAN RIDGING OVER WRN CONUS
-- GENERALLY FROM 4-CORNERS REGION NWD ACROSS NRN ROCKIES -- AND
TROUGHING FROM NRN QUE ACROSS MID MS VALLEY TO NERN MEX. HEIGHTS
ARE FCST TO CONTINUE FALLING OVER PACIFIC NW...AS SHORTWAVE TROUGH
ORBITING SRN SEMICIRCLE OF GULF OF AK CYCLONE APCHS REGION. AWAY
FROM PRIMARY/NRN STREAM FLOW BELT...DIFFUSE MID-UPPER TROUGH SHOULD
TURN EWD SLOWLY ACROSS W-CENTRAL/CENTRAL TX...WHILE QUASISTATIONARY
TROUGH OVER SERN GULF CONTINUES TO AID CONVECTIVE ENVIRONMENT OVER
FL AND ADJACENT WATERS. SHORTWAVE TROUGH -- INITIALLY EVIDENT OVER
MO -- IS FCST TO DRIFT EWD TOWARD SRN IL OVERNIGHT.

AT SFC...PATTERN WAS DOMINATED BY MESOSCALE AND SMALLER BOUNDARIES
INSTEAD OF WELL-DEFINED SYNOPTIC/SUBSYNOPTIC FRONTS...ESPECIALLY
OVER S-CENTRAL/SWRN CONUS WHERE MAJORITY OF CONVECTION IS OCCURRING
WITH AT LEAST MRGL SVR POTENTIAL. AT 23Z...DIFFUSE FRONTAL ZONE --
MODULATED LOCALLY BY CONVECTIVE OUTFLOWS -- WAS EVIDENT FROM
S-CENTRAL MO OZARKS SWWD THROUGH E-CENTRAL OK...THEN WSWWD ACROSS
CENTRAL/SWRN OK....AND E-CENTRAL NM. MOST OF OK SEGMENT OF THIS
BAROCLINIC ZONE SHOULD REMAIN QUASISTATIONARY THROUGH REMAINDER
PERIOD...WHILE HIGH PLAINS SEGMENT WILL DRIFT S.
SECONDARY/REINFORCING BOUNDARY WAS MOVING SEWD FROM S-CENTRAL KS
INTO NWRN/N-CENTRAL OK.

...OZARKS REGION...SRN PLAINS...
LARGE-SCALE ASCENT AND BELT OF ENHANCED MID-UPPER WINDS S OF MO
UPPER WAVE SHOULD ASSIST IN MAINTAINING FAVORABLE ENVIRONMENT FOR
ORGANIZED CONVECTION ACROSS THIS REGION RELATIVELY DEEP INTO THIS
EVENING. ALTHOUGH ISOLATED STG TSTMS WILL BE POSSIBLE FARTHER W AND
SW ACROSS OK...GREATEST CONVECTIVE CONCENTRATION -- AS WELL AS
CONTINUING SVR PROBABILITIES -- WILL REMAIN OVER OZARKS...AS OUTFLOW
BOUNDARY ENCOUNTERS RELATIVELY HIGH-THETAE AIR MASS THAT WILL TAKE
LONGER TO DIABATICALLY STABILIZE OVERNIGHT. THIS AIR MASS IS
CHARACTERIZED BY SFC DEW POINTS MID 60S TO LOW 70S F...CONTRIBUTING
TO AROUND 1000 J/KG MLCAPE PER MODIFIED RAOBS AND RUC SOUNDINGS.

FARTHER S ACROSS CENTRAL/W-CENTRAL TX...SCATTERED/LOCALLY NUMEROUS
NON-SVR TSTMS COVER SWATH FROM NEAR AUS-ABI-FST. DIABATIC BOUNDARY
LAYER COOLING...LACK OF APPRECIABLE DEEP-LAYER SHEAR...AND GROWING
COVERAGE OF OUTFLOW-STABILIZED AIR ALL INDICATE SVR POTENTIAL TOO
LOW FOR PROBABILITIES.

...LOWER CO RIVER REGION...
VERY HOT AND DEEPLY MIXED SUBCLOUD LAYERS WILL SUPPORT POTENTIAL FOR
STG/ISOLATED SVR GUSTS WITH PULSE AND MULTICELL TSTMS OVER THIS
REGION FOR ANOTHER 2-3 HOURS. MLCAPE CURRENTLY AROUND 1000-1500
J/KG IS EXPECTED TO DIMINISH RAPIDLY ONCE DIABATIC SFC COOLING
COMMENCES...INCREASING CINH AS WELL...AND LESSENING POTENTIAL FOR
INTENSE GUSTS TO REACH SFC.

..EDWARDS.. 09/05/2009

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