SPC AC 100553
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT THU JUN 10 2010
VALID 101200Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE PLAINS...
...PLAINS...
WRN U.S. TROUGH WILL GRADUALLY EASE INTO THE GREAT BASIN BY THE END
OF THE PERIOD WHICH WILL FORCE THE STRONGEST BELT OF MID-HIGH LEVEL
FLOW FROM CNTRL CA/NV...NEWD ACROSS NRN UT INTO CNTRL WY. THIS
LARGE SCALE EVOLUTION WILL ENSURE SUSTAINED LEE TROUGHING ACROSS THE
SRN PLAINS WHILE A FAIRLY WELL DEFINED SFC CYCLONE SHOULD DEVELOP
OVER ECNTRL CO BY MID AFTERNOON. AS A RESULT...MOIST UPSLOPE FLOW
WILL BE WELL ENTRENCHED ACROSS CO NORTH OF I-70 INTO SERN WY. IN
FACT...LATEST NAM INSISTS THAT ELY FLOW WILL DEEPEN THROUGH AT LEAST
1 KM ACROSS THE HIGH PLAINS WHICH WILL ENHANCE THE PROSPECT FOR
ROBUST CONVECTIVE DEVELOPMENT BY 20-21Z ALONG SRN FRINGE OF STRONGER
FLOW ALOFT OVER THE HIGHER TERRAIN OF NRN CO/SRN WY BEFORE
SUBSEQUENT MOVEMENT AND SUPERCELL EVOLUTION ALLOWS STORMS TO
PROPAGATE TOWARD THE PLAINS. LARGE HAIL CERTAINLY SEEMS POSSIBLE
WITHIN AN ENVIRONMENT LIKELY CHARACTERIZED BY STEEP LAPSE RATES AND
DEEP LAYER VERTICAL SHEAR MORE THAN ADEQUATE FOR SUSTAINED ROTATING
UPDRAFTS. ANY TSTMS THAT ADVECT TOWARD THE PLAINS WILL LIKELY
STRENGTHEN AS THEY ENCOUNTER A MODERATELY UNSTABLE AIRMASS WHERE
SBCAPE VALUES WILL RANGE FROM 2000-3000 J/KG. ELY LOW LEVEL FLOW
AND SUFFICIENTLY LOW CLOUD BASES...TEMP/DEW POINT SPREADS ON THE
ORDER OF 20-25 DEG...SUGGEST ISOLATED TORNADOES MAY OCCUR WITH MORE
SUSTAINED SUPERCELL STRUCTURES. ADDITIONALLY...LATEST MODEL
GUIDANCE INDICATES VERY LARGE HAIL COULD ALSO ACCOMPANY THE
STRONGEST UPDRAFTS. ALTHOUGH EARLY MORNING THUNDERSTORM ACTIVITY
WILL LIKELY MIGRATE ACROSS A GOOD PORTION OF NRN NEB/SRN SD...THE
PRIMARY SEVERE THREAT WILL ORIGINATE LATE IN THE PERIOD ACROSS THE
HIGH PLAINS BEFORE AN OVERNIGHT MCS ONCE AGAIN SPREADS INTO THE
CNTRL PLAINS ALONG THE NOSE OF LLJ.
FARTHER SOUTH...VERY STRONG HEATING ALONG THE DRYLINE ACROSS THE SRN
PLAINS WILL RESULT IN SFC PARCELS REACHING THEIR CONVECTIVE
TEMPERATURES BY 22Z...SWD TO THE MEXICAN BORDER. FORECAST SOUNDINGS
SUGGEST STRONG INSTABILITY WITH SBCAPE VALUES APPROACHING 4000 J/KG
COULD BE IN PLACE PRIOR TO CONVECTIVE DEVELOPMENT. ALTHOUGH DEEP
LAYER SHEAR IS NOT EXPECTED TO BE THAT STRONG...MID LEVEL FLOW IS
FORECAST TO INCREASE TO AT LEAST 20-25KT AS FAR SOUTH AS THE NRN TX
PANHANDLE AS WRN TROUGH APPROACHES. THIS SHOULD BE MORE THAN
ADEQUATE FOR SLOW MOVING SEVERE MULTI-CELL OR PERHAPS ISOLATED
SUPERCELLS. LARGE HAIL AND GUSTY WINDS ARE THE SEVERE THREATS WITH
THESE MODESTLY HIGH BASED STORMS.
...GULF STATES...
BOTH THE GFS AND NAM SUGGEST THE EAST TX UPPER TROUGH WILL FINALLY
EJECT NEWD LATE IN THE PERIOD IN RESPONSE TO WEAK HEIGHT FALLS OVER
THE SWRN U.S. A CONTINUATION OF MODEST SWLY FLOW THROUGH MID LEVELS
WILL EXTEND FROM THE LOWER SABINE RIVER INTO THE N CNTRL GULF
STATES. ANY STORMS THAT DEVELOP WITHIN THIS BELT OF STRONGER FLOW
COULD CERTAINLY OBTAIN WEAK ORGANIZED STRUCTURES AND ISOLATED STRONG
DOWNBURSTS COULD BE NOTED DURING THE HEAT OF THE AFTERNOON WHEN
THUNDERSTORM ACTIVITY WILL BE MAXIMIZED.
..DARROW/GARNER.. 06/10/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
|
