SWODY1
SPC AC 220057
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0757 PM CDT SAT MAR 21 2009
VALID 220100Z - 221200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
BROADER UPPER-AIR PATTERN IS CHARACTERIZED BY MEAN RIDGING FROM NERN
MEX NWD OVER PLAINS STATES TO NRN SASK/WRN MB...WITH HIGH-AMPLITUDE
TROUGHING OFFSHORE ATLANTIC/PACIFIC COASTS. LOW-AMPLITUDE SHORTWAVE
TROUGH IS MOVING EWD ACROSS PORTIONS OK/N TX ATTM -- PAST MEAN RIDGE
POSITION -- AND IS FCST TO CONTINUE WEAKENING OVER AR BY END OF
PERIOD. PRIMARY PACIFIC SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE
CHANNEL IMAGERY INVOF 130W -- IS FCST TO MOVE ONSHORE CA COAST AT OR
JUST AFTER 12Z.
LARGE AREA OF MID-UPPER HEIGHT FALLS ACROSS PACIFIC COAST STATES EWD
OVER GREAT BASIN/INTERMOUNTAIN REGIONS SHOULD SPREAD EWD TOWARD
ROCKIES OVERNIGHT. AS THIS OCCURS...LEE-SIDE/LOW-LEVEL TROUGHING
WILL BECOME BETTER DEFINED OVER HIGH PLAINS...INCLUDING
DEVELOPMENT/DEEPENING OF EMBEDDED LOW OVER SRN MT. WARM FRONT --
ANALYZED AT 23Z FROM LOW GENERALLY ESEWD ACROSS SERN
MT...CENTRAL/SERN SD AND NRN IA -- SHOULD DRIFT NWD THROUGH
REMAINDER PERIOD.
...CENTRAL HIGH PLAINS...
ISOLATED TO WIDELY SCATTERED TSTMS -- ONE OR TWO BRIEFLY ATTAINING
SVR LEVELS -- ARE EVIDENT ATTM FROM NERN CO TO NERN WY. THIS IS
DIURNALLY DRIVEN CONVECTION -- INITIATED AMIDST STG SFC HEATING ON
HIGH PLAINS. WELL-MIXED/DEEP SUBCLOUD LAYERS AND FAVORABLE
LOW-LEVEL SHEAR INDICATE CONTINUED POTENTIAL FOR SOME STORM-SCALE
ROTATION...ISOLATED SVR HAIL AND A FEW STG-SVR GUSTS UNTIL THIS
ACTIVITY DISSIPATES. MODIFIED RAOBS AND RUC FCST SOUNDINGS SUGGEST
THAT SFC COOLING WILL REDUCE BUOYANCY SUBSTANTIALLY AND IN SHORT
TIME FRAME -- 1-2 HOURS. PRIND MOST CONVECTION THEREFORE WILL
WEAKEN RAPIDLY AFTER DARK.
...NRN PLAINS...
WIDELY SCATTERED TSTMS MAY OCCUR OVERNIGHT ACROSS PORTIONS CENTRAL
SD NWWD TO NERN MT...IN ZONE OF ELEVATED LOW LEVEL WAA AND STG
ISENTROPIC LIFT. SD PORTION COULD BE EITHER EWD
EXTENSION/PERSISTENCE OF ISOLATED CONVECTIVE REGIME NOW OVER NERN WY
AND NWRN NEB PANHANDLE...OR SEPARATE DEVELOPMENT ALTOGETHER WITH
PARCELS ISENTROPICALLY LIFTED TO LFC INVOF MRGLLY MOIST/40-50 KT SLY
LLJ. SOME OF THIS ACTIVITY MAY PRODUCE HAIL...WITH EFFECTIVE SHEAR
MAGNITUDES REACHING 35-40 KT FOR GREATEST CAPE DEPTHS...STEEP
MIDLEVEL LAPSE RATES...AND ELEVATED MUCAPE IN 500-800 J/KG RANGE.
POTENTIAL APPEARS TOO ISOLATED AND CONDITIONAL FOR AOA 5-PERCENT
GRID PROBABILITIES.
..EDWARDS.. 03/22/2009
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment