SPC AC 011720
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1220 PM CDT THU SEP 01 2011
VALID 021200Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM SRN WI INTO LOWER MI...
...SYNOPSIS...
A BROAD UPPER TROUGH WITH 60-70 KT MID LEVEL JET CORE WILL STRETCH
FROM THE NRN ROCKIES EWD ACROSS THE NRN PLAINS AND INTO THE GREAT
LAKES. A LEAD DISTURBANCE WILL MOVE FROM NRN MN/WRN ONTARIO NEWD
TOWARD HUDSON BAY...WHILE ANOTHER VORTICITY MAX SETTLES INTO MT WITH
LOW CENTERED OVER SK. AT THE SURFACE...A COLD FRONT ASSOCIATED WITH
THE LEAD WAVE WILL EXTEND FROM NRN MN INTO SRN WI AND BECOMING
STATIONARY INTO KS LATE. AMPLE MOISTURE WILL EXIST AHEAD OF THE
FRONT FOR SCATTERED THUNDERSTORMS...A FEW OF WHICH MAY BE SEVERE.
TO THE E...AN UPPER HIGH WILL BE CENTERED OVER THE OH/TN VALLEY
REGION...WITH NLY FLOW ALOFT FROM THE APPALACHIANS TO THE E COAST ON
ERN PERIPHERY OF THE HIGH. HERE...A WEAK SURFACE TROUGH IS FORECAST
DURING THE AFTERNOON WHICH MAY BE ENOUGH FOR A FEW STRONG TO SEVERE
STORMS.
ELSEWHERE...A TROPICAL CYCLONE IS FORECAST TO STRENGTHEN OVER THE
NRN GULF OF MEXICO THROUGH THE PERIOD WHILE DRIFTING IN A GENERAL
NWD DIRECTION...AFFECTING THE N CNTRL GULF COAST.
...SRN WI INTO MI AND EXTREME NRN IL...
SCATTERED SHOWERS AND STORMS SHOULD BE ONGOING NEAR A COLD FRONT
FROM NEB INTO UPPER MI EARLY ON FRI...WITH STORMS EVOLVING DURING
THE DAY AND SHIFTING EWD ACROSS WI AND INTO LOWER MI BY AFTERNOON.
STEEP LAPSE RATES AND AMPLE INSTABILITY WILL EXIST AS WELL AS DEEP
LAYER FLOW FOR SEVERE STORMS TO BECOME ORGANIZED. RELATIVELY
STRAIGHT HODOGRAPHS SUGGEST MINIMAL SUPERCELL THREAT WITH CLUSTERS
OR LINE SEGMENTS MORE LIKELY. AS SUCH...BOTH WIND AND HAIL WILL BE A
THREAT.
...SRN LA/MS/AL...
MODELS INDICATE STRENGTHENING WIND FIELDS...AS WELL AS PRECIPITABLE
WATER ACROSS MUCH OF SRN LA INTO SRN MS/AL WITH THE APPROACHING
TROPICAL CYCLONE. IF THIS DEVELOPS AS EXPECTED...HODOGRAPHS WOULD
FAVOR ROTATING STORMS WITHIN RAIN BANDS...AND GIVEN DEWPOINTS IN THE
UPPER 70S F...THE VIRTUAL TEMPERATURE CORRECTION WOULD YIELD
SUFFICIENT CAPE FOR A FEW TORNADOES. GIVEN THE SYSTEM IS IN THE
FORMATIVE STAGE...WILL DEFER A POSSIBLE TC TORNADO-DRIVEN SLIGHT
RISK TO LATER OUTLOOKS.
...SWRN PA/WV INTO WRN VA AND NC...
WEAK LOW LEVEL WARM ADVECTION WILL EXIST WITH 850 THETA-E ADVECTION
OUT OF THE NW. WEAK CONVERGENCE IS FORECAST BY AFTERNOON...AND WITH
STRONG HEATING...CONVECTIVE INHIBITION SHOULD BECOME NEGLIGIBLE.
FORCING FOR CONVECTION WILL BE THE MAIN LIMITING FACTOR TO GREATER
STORM COVERAGE. HOWEVER...IT DOES APPEAR THAT AT LEAST ISOLATED
STORMS MAY OCCUR...WITH A CONDITIONAL THREAT OF BOTH HAIL AND GUSTY
WINDS
..JEWELL.. 09/01/2011
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
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