SPC AC 242328
DAY 1 CONVECTIVE OUTLOOK CORR 2
NWS STORM PREDICTION CENTER NORMAN OK
0628 PM CDT SAT MAY 24 2008
VALID 252322Z - 251200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE PLAINS FROM PARTS OF
W TX TO ND...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF FL PENINSULA TO
SERN GA...
UPDATED TO EXTEND THE SLIGHT RISK SWWD INTO W TX...NWD INTO CENTRAL
ND AND EXTEND A SLIGHT RISK NWD INTO SERN GA
...DAKOTAS...
SLIGHT RISK HAS BEEN EXTENDED NWD INTO CENTRAL ND TO ACCOUNT FOR
SEVERE WEATHER THREAT SPREADING NNEWD THIS EVENING. FOR MESOSCALE
INFORMATION AND SEVERE WEATHER DETAILS...REFER TO SPC MESOSCALE
DISCUSSIONS AND RELEVANT WATCHES FOR THIS REGION.
...W/NW TX INTO SWRN OK...
SLIGHT RISK HAS BEEN EXTENDED SWWD INTO THIS REGION TO ACCOUNT FOR
RECENT STRONG TSTM DEVELOPMENT ALONG RETREATING DRY LINE...WHICH
EXTENDED FROM WEST CENTRAL OK SWWD TO THE TRANSPECOS AREA OF SW TX.
LATEST MODELS SUGGEST DRY LINE WILL CONTINUE TO RETREAT WNWWD
THROUGH AS SELY LOW LEVEL JET STRENGTHENS TO 40-50 KT THIS EVENING
THROUGH TONIGHT. STEEP MID LEVEL LAPSE RATES /UP TO 8 C/KM/ AND
MODERATE INSTABILITY SUPPORT A POTENTIAL FOR VERY LARGE HAIL IN
ADDITION TO STRONG WIND GUSTS. WAA/ASCENT ALONG AXIS/NOSE OF THIS
JET SHOULD SUPPORT ADDITIONAL TSTM DEVELOPMENT THROUGH THE
EVENING...WITH MODELS INCLUDING THE SREF SUGGESTING DEVELOPMENT
FARTHER NWWD INTO NW TX AND SWRN OK BY LATE EVENING. FOR MESOSCALE
INFORMATION AND SEVERE WEATHER DETAILS...REFER TO SPC MESOSCALE
DISCUSSIONS AND RELEVANT WATCHES FOR THIS REGION.
...SERN GA/NERN FL PENINSULA...
EFFECTIVE BULK SHEAR RANGING FROM 40-50 KT ACROSS ERN/SERN GA WILL
DEVELOP SWD INTO NERN FL THIS EVENING AS SRN EXTENT OF ERN SEABOARD
TROUGH CONTINUES TO AFFECT THIS REGION. THIS COMBINED WITH MODERATE
INSTABILITY WILL SUPPORT ORGANIZED STORMS...WITH ACTIVITY TRACKING
SEWD WITHIN WNWLY FLOW ALOFT. FOR MESOSCALE INFORMATION AND SEVERE
WEATHER DETAILS...REFER TO SPC MESOSCALE DISCUSSIONS AND RELEVANT
WATCH FOR THIS REGION.
..PETERS..
...PREVIOUS DISCUSSION... /ISSUED AT 20Z/
...CNTRL AND NRN PLAINS...
LATEST WATER VAPOR IMAGERY SHOWS A WELL-DEFINED UPPER-LEVEL LOW OVER
THE NRN HIGH PLAINS. A STRONG 85 TO 100 KT MID-LEVEL JET IS LOCATED
FROM SE CO EXTENDING NNEWD INTO CNTRL NEB. AT THE SFC...A 997 MB LOW
IS LOCATED IN FAR SE MT WITH A PRONOUNCED WARM FRONT EXTENDING SEWD
ACROSS SRN SD INTO NERN NEB. RAPID MOISTURE ADVECTION IS OCCURRING
IN THE CNTRL PLAINS ASSOCIATED WITH A 40 TO 50 KT LOW-LEVEL JET. SFC
DEWPOINTS SHOULD INCREASE INTO THE MID TO UPPER 60S F IN ERN NEB AND
INTO THE LOWER 60S F IN ERN SD. MODERATE INSTABILITY SHOULD BE IN
PLACE ALONG THE MOIST AXIS BY LATE AFTERNOON WITH SCATTERED
THUNDERSTORMS INITIATING AND MOVING NEWD ACROSS THE REGION.
SHORT-TERM MODEL FORECASTS SUGGEST THE SHORTWAVE TROUGH SOUTHEAST OF
THE UPPER-LEVEL LOW IS SLIGHTLY OUT OF PHASE WITH THE INSTABILITY
AXIS. THIS SHOULD ENCOURAGE CONVECTIVE INITIATE ON THE ERN EDGE OF
THE INSTABILITY AXIS AS THE SHORTWAVE TROUGH MOVES AWAY FROM THE
REGION THIS EVENING. MCS DEVELOPMENT APPEARS LIKELY ACROSS ERN SD
AND WRN MN WHERE FORCING WITH THE UPPER-LEVEL TROUGH AND LIFT FROM
THE LOW-LEVEL JET WILL BE MAXIMIZED. FURTHER SOUTH IN ERN
NEB...THUNDERSTORMS SHOULD DEVELOP IN RESPONSE TO LOW-LEVEL
CONVERGENCE AND DESTABILIZATION. SEVERAL THUNDERSTORM CLUSTERS
SHOULD DEVELOP IN THIS PART OF THE REGION AS WELL.
CONCERNING THE SHEAR ENVIRONMENT...FORECAST SOUNDINGS ACROSS THE
CNTRL AND NRN PLAINS SHOW STRONG TO VERY STRONG VERTICAL SHEAR
PROFILES WITH 0-6 KM SHEAR VALUES RANGING FROM 80 TO 90 KT ACROSS
NEB AND SD TO AROUND 50 KT IN NERN KS. AS INSTABILITY
INCREASES...THE STRONG SHEAR AND STEEP MID-LEVEL LAPSE RATES EVIDENT
ON OBJECTIVE ANALYSIS OVER SD AND NEB SHOULD SUPPORT SUPERCELLS WITH
LARGE HAIL. IN ADDITION...REGIONAL PROFILERS SUGGEST LOW-LEVEL SHEAR
PROFILES WILL BE FAVORABLE FOR TORNADOES WITH THE MORE PERSISTENT
ROTATING STORMS. THE MOST LIKELY AREA FOR AN ISOLATED STRONG TORNADO
SHOULD BE ACROSS ERN NEB WHERE THE COMBINATION OF LOW-LEVEL SHEAR
AND INSTABILITY WILL BE MAXIMIZED. THE SEVERE THREAT SHOULD CONTINUE
THROUGH THE EVENING WITH LARGE HAIL AND DAMAGING WINDS POSSIBLE AS
AN MCS OR SEVERAL THUNDERSTORM CLUSTERS MOVE INTO THE ERN PART OF
THE SLIGHT RISK AREA.
...SRN PLAINS...
LATEST SFC ANALYSIS SHOWS AN AXIS OF LOW-LEVEL MOISTURE EXTENDING
NNWWD ACROSS CNTRL OK INTO SRN KS WHERE DEWPOINTS ARE IN THE LOWER
70S F. OBJECTIVE ANALYSIS SHOWS MODERATE TO STRONG INSTABILITY IN
PLACE ACROSS MOST OF OK WITH MLCAPE VALUES IN THE 3000 TO 4000 J/KG
RANGE. SEVERAL INTENSE SUPERCELLS ARE ONGOING ALONG THE NRN EDGE OF
THE INSTABILITY AXIS. PROFILERS ACROSS THE AREA SHOW MODERATE
VERTICAL SHEAR WHICH WILL SUPPORT SUPERCELLS FOR THE REMAINDER OF
THE AFTERNOON INTO THE EVENING. THE STORMS ARE VERY NEAR THE WRN
EDGE OF A LOW-LEVEL CONVERGENCE BOUNDARY. BACKED SFC WINDS NORTH OF
THE BOUNDARY AND ABOUT 20 KT OF LOW-LEVEL FLOW SHOWN BY PROFILERS
ASSOCIATED THE AXIS OF A LOW-LEVEL JET WILL CONTINUE A TORNADO
THREAT ACROSS NRN OK...SEE MCD 1005...AS THE LOW-LEVEL JET INCREASES
LATE THIS AFTERNOON...THE THREAT FOR TORNADOES MAY EXPAND INTO SRN
KS. AN ISOLATED STRONG TORNADO OR TWO WILL BE POSSIBLE. THE STRONG
INSTABILITY AND STEEP MID-LEVEL LAPSE RATES WILL ALSO SUPPORT VERY
LARGE HAIL WITH THE MORE INTENSE SUPERCELLS.
...GA/FL...
THE LATEST SFC ANALYSIS ACROSS THE REGION SHOWS MID TO UPPER 60S F
DEWPOINTS ACROSS THE FL PENINSULA EXTENDING NWD INTO CNTRL GA.
MODERATE INSTABILITY IS LOCATED ACROSS MUCH OF GA SWD ACROSS THE ERN
PART OF THE FL PENINSULA. SCATTERED STRONG TO SEVERE STORMS ARE
ONGOING IN ERN FL AND THIS ACTIVITY SHOULD CONTINUE FOR SEVERAL MORE
HOURS. FORECAST SOUNDINGS SUGGEST VERTICAL SHEAR AND STEEP LOW-LEVEL
LAPSE RATES ACROSS ERN FL WILL SUPPORT MULTICELL CLUSTERS CAPABLE OF
PRODUCING ISOLATED WIND DAMAGE. THE SEVERE THREAT SHOULD BE TIED
CLOSELY TO PEAK HEATING. FURTHER NORTH ACROSS ERN GA...OBJECTIVE
ANALYSIS SHOWS MODERATE VERTICAL SHEAR IN PLACE. THIS ALONG WITH
COLD AIR ALOFT ASSOCIATED WITH AN EAST COAST UPPER-LEVEL TROUGH MAY
SUPPORT A THREAT FOR ISOLATED SUPERCELLS WITH HAIL.
...PACIFIC NORTHWEST...
LATEST WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL LOW OVER NRN CA.
STRONG LARGE-SCALE ASCENT AND COLD AIR ALOFT WITH THE UPPER-LEVEL
LOW SHOULD ALLOW SCATTERED THUNDERSTORMS TO DEVELOP BY LATE
AFTERNOON ACROSS THE REGION. STEEP MID-LEVEL LAPSE RATES MAY SUPPORT
AN ISOLATED HAIL THREAT WITH THE STRONGER CORES WITH THE GREATEST
THREAT ALONG AN AXIS OF INSTABILITY FROM SWRN ID NWWD ACROSS CNTRL
ORE.
..BROYLES.. 05/24/2008
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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