SWODY2
SPC AC 071713
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1113 AM CST SUN MAR 07 2010
VALID 081200Z - 091200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
AN ALREADY POWERFUL MID AND UPPER-LEVEL LOW INITIALLY CENTERED OVER
THE SRN ROCKIES WILL INTENSIFY FURTHER WHILE TRANSLATING NEWD INTO
THE CNTRL PLAINS BY TUESDAY MORNING. THIS SYSTEM WILL BE
ACCOMPANIED BY A 70-80 KT MIDLEVEL JET STREAK AND A CORRIDOR OF
12-HR HEIGHT FALLS OF 100-150 M WHICH WILL OVERSPREAD THE SRN PLAINS
THROUGH THE PERIOD.
AT THE SURFACE...AN ELONGATED LOW PRESSURE AREA INITIALLY OVER THE
CNTRL AND SRN HIGH PLAINS WILL CONSOLIDATE INTO A DEEPENING CYCLONE
OVER THE TX/OK PNHDLS MONDAY PRIOR TO OCCLUDING AND SLOWLY FILLING
OVER THE SAME GENERAL AREA DURING THE LATTER HALF OF THE FORECAST
PERIOD. PACIFIC FRONT ASSOCIATED WITH THIS SYSTEM WILL PUSH
EWD/NEWD THROUGH WRN INTO CNTRL PARTS OF OK AND TX...WHILE A WARM
FRONT LIFTS MORE SLOWLY NWD THROUGH CNTRL AND ERN PARTS OF TX.
LATEST MODEL GUIDANCE SUGGESTS THAT THE GREATEST POTENTIAL FOR A FEW
SEVERE STORMS WILL BE CONFINED TO A COUPLE OF AREAS: ONE NEAR THE
OCCLUDING SURFACE CYCLONE OVER THE SRN HIGH PLAINS...AND THE OTHER
NEARER TO THE SYSTEM WARM SECTOR OVER PARTS OF CNTRL/SRN TX.
...OK/TX PNHDLS...SWRN KS...WRN OK...
CLUSTERS OF MAINLY ELEVATED TSTMS ARE EXPECTED TO SPREAD NEWD
THROUGH REGION EARLY IN THE DAY IN ASSOCIATION WITH THE LEADING EDGE
OF STRONGER HEIGHT FALLS ATTENDANT TO UPPER SYSTEM. FORECAST
SOUNDINGS SUGGEST THAT ELEVATED CONVECTIVE INSTABILITY WILL REMAIN
MARGINAL WHICH SHOULD LIMIT THE POTENTIAL FOR AN ORGANIZED SEVERE
HAIL THREAT.
BY AFTERNOON...A SERIES OF LOW-TOPPED STORMS ARE LIKELY TO DEVELOP
FROM VICINITY OF OCCLUDING SURFACE LOW SEWD ALONG PACIFIC/OCCLUDED
FRONT WITHIN A THERMODYNAMIC ENVIRONMENT CHARACTERIZED BY MARGINAL
BOUNDARY LAYER MOISTURE /DEWPOINTS IN THE 40S TO LOW 50S/ BUT STEEP
LAPSE RATES. DEEP-LAYER VERTICAL SHEAR WILL BE DECREASING WITH TIME
OWING TO APPROACH OF MIDLEVEL LOW...BUT LOW-LEVEL WIND PROFILE WILL
EXHIBIT MODEST VEERING E OF SURFACE FRONT. THE PRIMARY HAZARD
ASSOCIATED WITH THESE DIURNAL STORMS WILL BE HAIL /SOME THAT MAY
APPROACH SEVERE CRITERIA/...THOUGH A BRIEF TORNADO IS ALSO POSSIBLE
NEAR SURFACE LOW WHERE AMBIENT VERTICAL VORTICITY IS MAXIMIZED.
...CNTRL OK INTO CNTRL/SRN TX...
HERE TOO...CLUSTERS OF ELEVATED TSTMS WILL BE POSSIBLE EARLY IN THE
DAY IN CONJUNCTION WITH STRENGTHENING WAA ALONG 40-50 KT LLJ AXIS.
THE MAJORITY OF THIS ACTIVITY WILL LIKELY BE LOCATED TO THE N OF
SURFACE WARM FRONT WITHIN A MARGINALLY UNSTABLE ENVIRONMENT. WITH
TIME...REGENERATIVE STORM DEVELOPMENT IS EXPECTED TO BUILD
PROGRESSIVELY SWD/SWWD...EVENTUALLY BECOMING ROOTED IN
MOISTENING/DESTABILIZING WARM SECTOR OVER PARTS OF CNTRL/SRN TX.
FARTHER N ALONG PACIFIC/OCCLUDED FRONT... ISOLATED...SURFACE-BASED
STORMS WILL BE POSSIBLE FROM CNTRL OK INTO N-CNTRL TX MONDAY
AFTERNOON INTO MONDAY NIGHT.
THE HIGHEST BOUNDARY LAYER MOISTURE CONTENT /I.E. DEWPOINTS IN THE
60S/ WILL REMAIN CONFINED TO ALONG AND S OF WARM FRONT OVER
CNTRL/SRN TX. HOWEVER...LAPSE RATES WILL BE WEAKER THAN LOCATIONS
TO THE N/NW...LIMITING MLCAPE TO GENERALLY LESS THAN 1000 J/KG.
MIDLEVEL WIND FIELD WILL STRENGTHEN THROUGH THE DAY TO THE S/SE OF
PARENT CIRCULATION /I.E. GENERALLY S OF THE RED RIVER/...RESULTING
IN INCREASINGLY LONG HODOGRAPHS. HOWEVER...STRONGER LOW-LEVEL SHEAR
ASSOCIATED WITH LLJ AXIS WILL REMAIN LARGELY DISPLACED TO THE NE/E
OF PRIMARY INSTABILITY AXIS THROUGH THE FORECAST PERIOD. THE NET
RESULT IS RATHER LONG...STRAIGHT HODOGRAPHS...SUPPORTIVE OF
ORGANIZED/ROTATING STORMS CAPABLE OF MAINLY HAIL AND DAMAGING
WINDS.
THE MARGINAL INSTABILITY REMAINS THE PRIMARY FACTOR LIMITING A MORE
ROBUST SEVERE WEATHER THREAT. THEREFORE...LOW SEVERE WEATHER
PROBABILITIES WILL BE MAINTAINED IN THIS FORECAST. AN UPGRADE TO
SLIGHT RISK MAY BECOME NECESSARY IN SUBSEQUENT DAY ONE OUTLOOKS ONCE
FINER-SCALE DETAILS IN THE MOISTURE/INSTABILITY FIELD BECOME MORE
CLEAR.
..MEAD.. 03/07/2010
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