Wednesday, August 13, 2008

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 131301
SWODY1
SPC AC 131259

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0759 AM CDT WED AUG 13 2008

VALID 131300Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SERN U.S....

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL PLNS INTO THE
MID MO VLY/SW MN...

...SYNOPSIS...
SWRN U.S. RIDGE EXPECTED TO BUILD N INTO THE PACIFIC NW THIS PERIOD
...AS BROAD AREA OF CYCLONIC FLOW CONTINUES TO PREVAIL FROM THE NRN
RCKYS AND THE PLNS TO THE E CST. WITHIN THE CYCLONIC REGIME...UPR
LOW NOW OVER SRN SK EXPECTED TO MOVE ONLY VERY SLOWLY S TO NEAR THE
SK/MT/ND BORDER AS A SERIES OF WEAK DISTURBANCES TRACK E/SE ALONG
ITS SRN FRINGE FROM THE RCKYS INTO THE PLNS. FARTHER
SE...AMPLIFYING SHORTWAVE TROUGH NOW OVER AL SHOULD CONTINUE E TO
THE CAROLINA CST THIS EVE BEFORE TURNING NE AND BECOMING ABSORBED
WITHIN LARGER SCALE CIRCULATION REDEVELOPING S AND W ACROSS QUEBEC.

AT THE SFC...WAVE ASSOCIATED WITH AL IMPULSE...NOW N OF CSG...
SHOULD TRACK E TO NEAR AGS BY MIDDAY...AND THEN ENE TO NEAR HATTERAS
THIS EVE. ELSEWHERE...WNWLY MID LVL FLOW AND HEATING WILL MAINTAIN
LEE TROUGH OVER THE CNTRL HI PLNS...AND A WIND SHIFT LINE ASSOCIATED
WITH SRN PART OF SK LOW WILL MOVE E ACROSS THE DAKS.

...SERN U.S...
CLUSTER OF LONG-LIVED STORMS NOW OVER W CNTRL/SW GA MARKS AREA OF
STRONGEST WAA/ASCENT ASSOCIATED WITH AL UPR IMPULSE AND SFC WAVE.
THE STORMS SHOULD CONTINUE GENERALLY E...ALONG AND AHEAD OF THE
WAVE...INTO SC BY EARLY AFTN. STRONG WIND FIELD ASSOCIATED WITH
ANOMALOUS UPR AIR PATTERN...AND BACKED NEAR-SFC FLOW NEAR SFC WAVE
...WILL CONTRIBUTE TO CONSIDERABLE LOW LVL SHEAR...WITH 0-1 KM
VALUES AOA 50 KT. COUPLED WITH DEEP NEARLY MOIST ADIABATIC
THERMODYNAMIC PROFILES AND WEAK SFC HEATING...SETUP MAY YIELD ISOLD
TORNADOES IN ADDITION TO BOWING SEGMENTS WITH SVR WIND.

S OF THE SFC WAVE...OTHER STORMS MAY STRENGTHEN IN RESPONSE TO
SOMEWHAT MORE SUBSTANTIAL HEATING OCCURRING ALONG TRAILING
CONFLUENCE BANDS/COLD FRONT OVER S GA AND NRN FL. SEASONABLY
STRONG...DEEP UNIDIRECTIONAL WLY FLOW MAY SUPPORT A FEW BOWING
SEGMENTS WITH HIGH WIND THROUGH MID TO LATE AFTN.

...SRN/CNTRL HI PLNS NE TO SW MN...
AREA OF MOISTENING/APPARENT DISTURBANCE IN WV IMAGERY NOW OVER SW
MT/WRN WY EXPECTED TO CONTINUE ESE TO THE CNTRL HI PLNS BY THIS EVE.
AT THE SAME TIME...NWLY MID LVL FLOW WILL MAINTAIN PLUME OF
STEEP MID LVL LAPSE RATES /7-8 C PER KM/ E/SE FROM THE RCKYS INTO
THE DAKS/NEB AND KS...ATOP CORRIDOR OF LWR 60S SFC DEWPOINTS
EXTENDING FROM THE CNTRL HI PLNS NEWD ALONG LEE TROUGH/WIND SHIFT
INTO SW MN.

ONGOING TSTMS IN NEB AND THE TX PANHANDLE LIKELY WILL PERSIST INTO
MIDDAY. ADDITIONAL STORMS SHOULD FORM WITH SFC HEATING INVOF THESE
EARLY STORMS...AND FARTHER W ALONG CNTRL PLNS LEE TROUGH...AS MT/WY
DISTURBANCE CONTINUES ESEWD. OTHER STORMS MAY FORM ALONG WIND SHIFT
LINE IN ERN SD/SW MN.

KINEMATICALLY...ENVIRONMENT OVER THE PLNS WILL BE SIMILAR TO THAT
OVER THE REGION YESTERDAY. VEERING PROFILES WITH GENERALLY WEAK LOW
TO MID LVL WINDS SURMOUNTED BY MODERATE TO STRONG UPR LVL WNW FLOW
WILL YIELD 35-40 KT DEEP NWLY SHEAR. MOISTURE AVAILABILITY WILL BE
MORE SUBSTANTIAL THAN YESTERDAY...WITH AVERAGE PW AOA 1 INCH.
OVERALL SETUP...WITH ABSENCE OF STRONG LOW LVL FORCING...SUGGESTS
LIKELIHOOD FOR SCTD MULTICELLS AND SUPERCELLS OVER THE CNTRL HI
PLNS...WITH MORE WIDELY SCTD ACTIVITY POSSIBLE NEWD TO SW MN. SVR
HAIL AND WIND...IN ADDITION TO ISOLD TORNADOES...WILL BE POSSIBLE
WITH THE STORMS.

THE HI PLNS STORMS LIKELY WILL GROW UPSCALE INTO SEVERAL SMALL
CLUSTERS THAT MOVE SSE ACROSS ERN CO/WRN KS AND THE OK/TX PANHANDLE
REGION AS SSWLY LLJ STRENGTHENS AND EVENTUALLY VEERS TONIGHT.

..CORFIDI/CROSBIE.. 08/13/2008

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