SPC AC 240554
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1254 AM CDT SAT MAY 24 2008
VALID 241200Z - 251200Z
...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NRN PLAINS TO LOWER MO
VALLEY...
...SYNOPSIS...
LARGE/RETROGRADING CYCLONIC GYRE CONTINUES TO DOMINATE UPPER AIR
PATTERN ACROSS CENTRAL/WRN CONUS. MEAN CENTER OF THIS FEATURE
SHOULD CONTINUE TO MOVE WWD...TOWARD NRN CA COAST...BEFORE IT
BECOMES QUASISTATIONARY.
SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY AND RAOB
ANALYSES OVER CO -- WILL CONTINUE LIFTING NWD AROUND ERN RIM OF
SYNOPTIC CYCLONE...AND SHOULD PHASE WITH ANOTHER PERTURBATION CLOSER
TO LOW. BY 25/00Z...NET RESULT SHOULD BE SMALL MID-UPPER LEVEL LOW
OVER ERN MT...WITH SHORTWAVE TROUGH CURVING EWD/SWD ACROSS SRN
ND...ERN SD AND N-CENTRAL NEB. MEANWHILE...E OF MEAN
RIDGE...SHORTWAVE TROUGH INITIALLY OVER UPPER MS VALLEY IS EXPECTED
TO MOVE RAPIDLY SEWD TODAY...MOVING OFFSHORE CAROLINAS AND ACROSS
ERN GA AROUND 25/00Z.
AT SFC...LOW OVER NRN CO WILL MOVE/REDEVELOP NWD TO NRN HIGH
PLAINS...NEARLY COLOCATED WITH MIDLEVEL VORTEX CENTER BY 25/00Z.
OCCLUDED FRONT LIKEWISE SHOULD MOVE NWD...ACROSS ERN WY...NEB
PANHANDLE AND INTO BLACK HILLS..WITH WEAK COLD FRONT SWD ACROSS WRN
KS AND TX PANHANDLE. FRONT SHOULD BECOME QUASISTATIONARY AND LOSE
IDENTITY FROM ERN TX PANHANDLE SSWWD ACROSS SERN NM OR FAR W TX.
INITIALLY STATIONARY FRONT OVER NRN KS IS FCST TO LIFT NEWD ACROSS
NEB...REACHING POSITION FROM NEAR MKC NWWD TO OCCLUSION TRIPLE POINT
OVER N-CENTRAL NEB BY 25/00Z. DRYLINE IS FCST BY THAT TIME FROM
CENTRAL NEB SWD OVER PORTIONS WRN OK.
...NRN PLAINS TO LOWER MO VALLEY...
SVR POTENTIAL TODAY SHOULD BE MAXIMIZED IN SWATH FROM VICINITY
OCCLUDED FRONT OVER WRN SD...SEWD ALONG WARM FRONT AND AHEAD OF
DRYLINE OVER PORTIONS LOWER MO VALLEY REGION. SVR RISK BECOMES
QUITE CONDITIONAL S OF NEB...AND SFC-BASED INSTABILITY WILL BECOME
VERY MRGL FROM WRN SD NWWD TOWARD UPPER LOW.
LOW LEVEL MOISTURE AND DIURNAL/DIABATIC HEATING EACH ARE FCST TO
INCREASE WITH SSEWD EXTENT IN BETWEEN DRYLINE AND WARM FRONT. SFC
DEW POINTS MID-UPPER 60S F -- ISOLATED LOW 70S -- ARE LIKELY WITH
MLCAPES RISING INTO 2500-3500 J/KG RANGE IN WARM/MOIST SECTOR.
HOWEVER...CONVECTIVE INITIATION AND COVERAGE BECOME MORE UNCERTAIN
WITH SWD EXTENT BECAUSE OF PROGGED WEAKER LOW LEVEL CONVERGENCE
INVOF THOSE BOUNDARIES.
VERTICAL SHEAR PROFILES WILL BE FAVORABLE FOR SUPERCELLS...SOME
PRODUCING TORNADOES AND LARGE HAIL...THROUGHOUT CORRIDOR FROM WRN
SD...WHERE CAPE WILL BE WEAK BUT DEEP-LAYER SHEAR FAVORABLE...TO ERN
KS/WRN MO. FCST SOUNDINGS SUGGEST STG TURNING WITH HEIGHT INVOF
WARM/OCCLUDED FRONTS...WITH ENLARGED LOW LEVEL HODOGRAPHS AVAILABLE
TO ANY TSTMS INTERACTING WITH THOSE FRONTS. MOST FAVORABLE
JUXTAPOSITION OF BUOYANCY AND SHEAR MAY BE OVER ERN
NEB...CORRESPONDING TO NARROW/NRN FRINGE OF WARM SECTOR NEAR AND SE
OF OCCLUSION TRIPLE POINT.
...PORTIONS FL AND SRN GA...
AS SHORTWAVE TROUGH APCHS FROM NW...EXPECT SFC CYCLOGENESIS OFFSHORE
ATLANTIC WITH FRONTOGENETIC SFC TROUGH EXTENDING WWD ACROSS FL/GA
BORDER REGION. ALTHOUGH CONVERGENCE INVOF THIS FEATURE SHOULD BE
LIMITED...GIVEN STG WLY FLOW COMPONENT S OF BOUNDARY...WIDELY
SCATTERED TO SCATTERED TSTMS MAY DEVELOP AMIDST STG DIURNAL HEATING
AND WEAKENING SBCINH THIS AFTERNOON. SFC DEWPOINTS UPPER 60S TO LOW
70S F WILL CONTRIBUTE TO MLCAPES 1500-2000 J/KG. DEEP LAYER SPEED
SHEAR...CONTRIBUTING TO EFFECTIVE BULK SHEAR MAGNITUDES 35-40
KT...MAY ORGANIZE TSTMS ENOUGH TO POSE THREAT FOR ISOLATED
HAIL...ALONG WITH STG/POTENTIALLY DAMAGING GUSTS.
..EDWARDS/GRAMS.. 05/24/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
|
