SWODY2
SPC AC 211722
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1222 PM CDT MON MAY 21 2007
VALID 221200Z - 231200Z
..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE CENTRAL
AND SOUTHERN PLAINS...
..SYNOPSIS...
UPPER TROUGH IN THE WEST...WILL SHIFT EAST AND DEEPEN WITH TIME AS
HIGH LEVEL SPEED MAX ROTATES FROM THE BACKSIDE TO THE FRONT OF THE
UPPER TROUGH. THIS WILL RESULT IN THIS SYSTEM TO COVER MUCH OF THE
INTERMOUNTAIN WEST AND NRN/CENTRAL ROCKIES DURING THE FORECAST
PERIOD. ASSOCIATED WITH THE JET MAX WILL BE A SIGNIFICANT SHORTWAVE
TROUGH...THAT IS EXPECTED TO BE EJECTED FROM THE GREAT BASIN INTO
THE CENTRAL ROCKIES...WHILE THE MAIN UPPER LOW CENTER SHIFTS FROM WY
NEWD INTO ND. AHEAD OF THESE FEATURES/UPPER TROUGH...A COLD FRONT IS
PROGGED TO MOVE EWD INTO THE PLAINS AND GENERALLY STRETCH FROM NWRN
MN SWWD THROUGH SWRN KS AND INTO EXTREME NERN NM BY LATE TUESDAY
AFTERNOON. STRONG MIXING SHOULD RESULT IN A WELL DEFINED DRYLINE
FROM SOUTHWEST KS SWD INTO THE EDWARDS PLATEAU OF TX.
ALSO OF CONCERN IS A WEAK SHORTWAVE TROUGH EMBEDDED WITH SRN
BRANCH...CURRENTLY LOCATED ACROSS WRN TX...THAT IS EXPECTED TO SHIFT
EWD INTO THE LOWER MS VALLEY DURING THE DAY TUESDAY.
..CENTRAL/SOUTHERN PLAINS...
SLY WINDS WILL GRADUALLY INCREASE BOUNDARY LAYER MOISTURE...WITH MID
TO UPPER 60 DEWPOINTS EXPECTED FROM THE EDWARDS PLATEAU NWD INTO WRN
KS BY AFTERNOON. THESE DEWPOINTS COMBINED WITH STEEP LAPSE RATES
ASSOCIATED WITH ELEVATED MIXED LAYER...WILL RESULT IN STRONG
INSTABILITY...MLCAPES FROM 2000-3000 J/KG. SPLIT FLOW ALOFT BETWEEN
NRN AND SRN BRANCH WILL RESULT IN INCREASING DIFFLUENCE ALOFT FROM
WRN TX NWD INTO WRN KS...THUSLY INCREASING THE CONVERGENCE ALONG THE
FRONT/DRYLINE. THIS SHOULD AID IN THE INITIATION OF A FEW STORMS
NEAR OR EAST OF THE SURFACE BOUNDARIES BY LATE AFTERNOON. ONCE
STORMS DEVELOP...VERTICAL WIND PROFILES ALONG AND EAST OF THE
FRONT/DRYLINE WOULD BE VERY FAVORABLE FOR SUPERCELLS. STRONG LOW
LEVEL SHEAR/SRH INDICATE THE POTENTIAL FOR THE STORMS TO PRODUCE
VERY LARGE HAIL AND TORNADOES...SOME POSSIBLY STRONG. HOWEVER...THE
STRONGEST MASS FLUX IS FORECAST TO BE LOCATED WELL NORTH OF THIS
REGION AND ALSO GIVEN THE LACK OF HEIGHT FALLS...WILL NOT UPGRADE TO
MODERATE RISK ATTM SINCE WEAK FORCING/CAPPING MAY LIMIT NUMBER OF
STORMS THAT DEVELOP.
..NRN PLAINS...
ALTHOUGH SLY WINDS WILL INCREASE AHEAD OF APPROACHING COLD FRONT
..LOW LEVEL TRAJECTORIES CONTINUE TO ADVECT A GREATLY MODIFIED AIR
MASS FROM THE NERN GULF OF MEXICO. THIS WILL RESULT IN ONLY WEAK
INSTABILITY. ALSO...FORCING IS EXPECTED TO BE QUITE STRONG AS UPPER
LOW MOVES NEWD FROM WY AND THE AREA IS LOCATED WITH UVV ASSOCIATED
WITH APPROACHING JET MAX. THEREFORE...CONSIDERABLE CLOUDS AND
PRECIPITATION WILL LIKELY MINIMIZE DIURNAL HEATING AND POTENTIAL FOR
WIDESPREAD SEVERE STORMS.
..ERN TX...
ALL MODELS INDICATE THAT THE SRN STREAM TROUGH IN WEST TX WILL SHIFT
EWD AND OUT OF THE AREA BY TUESDAY AFTERNOON. WIDESPREAD CLOUDS AND
CONVECTION ARE EXPECTED TODAY...BUT SUSPECT AREA WILL BE IN
SUBSIDENCE ON TUESDAY. HOWEVER...IF ANY STORMS DO DEVELOP ALONG
LEFTOVER BOUNDARIES...MODERATE INSTABILITY AND WEAK BUT VEERING WIND
PROFILES WOULD SUPPORT AN ISOLATED SEVERE THREAT. SINCE CONVECTIVE
INITIATION APPEARS A LITTLE LESS LIKELY THAN PREVIOUS MODEL
RUNS...WILL ONLY GO WITH LOW SEVERE PROBABILITIES ATTM.
.IMY.. 05/21/2007
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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 chris@lib.siu.edu.
No comments:
Post a Comment