SPC AC 190038
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0738 PM CDT FRI JUL 18 2008
VALID 190100Z - 191200Z
...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT ACROSS PARTS OF THE NRN
PLAINS....
...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT ACROSS PARTS OF THE
NORTHEAST STATES....
...NORTHERN PLAINS...
DESTABILIZATION HAS BEEN RELATIVELY MODEST ACROSS THE NORTHERN HIGH
PLAINS...WITH MIXED LAYER/MOST UNSTABLE CAPE ON THE ORDER OF 1000-
2000 J/KG. BUT...DEEP LAYER SHEAR IS STRONG ALONG AND JUST TO THE
COOL SIDE OF THE LOWER/MID TROPOSPHERIC BAROCLINIC ZONE EXTENDING
FROM ROUGHLY NEAR THE EASTERN MONTANA/WYOMING BORDER THROUGH WESTERN
SOUTH DAKOTA. THIS BOUNDARY APPEARS LIKELY TO BECOME THE FOCUS FOR
CONSOLIDATING CONVECTION EARLY THIS EVENING...AIDED BY AN AREA OF
STRONGER DIVERGENCE ALOFT...SPREADING EASTWARD TO THE SOUTH/EAST OF
THE MAIN UPSTREAM SHORT WAVE TROUGH/CLOSED LOW... WHICH IS NOW
SLOWLY TURNING EASTWARD THROUGH ALBERTA/WESTERN MONTANA. THE
EASTERLY COMPONENT TO THE LOW-LEVEL FLOW FIELDS ...BENEATH WESTERLY
MID-LEVEL FLOW...IS EXPECTED TO CONTRIBUTE TO A VERY FAVORABLE
SYSTEM RELATIVE FLOW CONFIGURATION FOR STRONG DAMAGING WINDS WITH
THE EVOLVING MESOSCALE CONVECTIVE SYSTEM... BEFORE ACTIVITY WEAKENS
IN A MORE STABLE ENVIRONMENT OVER CENTRAL SOUTH DAKOTA LATER
TONIGHT.
...NORTHEAST STATES...
CONVECTION CONTINUES TO DEVELOP ACROSS PARTS OF SOUTHEASTERN
ONTARIO/SOUTHWESTERN QUEBEC INTO NORTHERN NEW YORK STATE...
ASSOCIATED WITH AN AREA OF STRONGER FORCING DOWNSTREAM OF THE MAIN
UPPER IMPULSE NOW BEGINNING TO ACCELERATE TOWARD THE ST. LAWRENCE
VALLEY. THIS FORCING IS EXPECTED TO SPREAD ALONG A QUASI-STATIONARY
FRONTAL ZONE ACROSS PARTS OF NORTHERN VERMONT/NEW HAMPSHIRE INTO
SOUTHERN MAINE THROUGH THE REMAINDER OF THE EVENING INTO THE
OVERNIGHT HOURS. DESPITE BOUNDARY LAYER
COOLING/STABILIZATION...THERMODYNAMIC PROFILES ACROSS THIS REGION
REMAIN SUPPORTIVE OF AN EVOLVING CONVECTIVE CLUSTER. COUPLED WITH
STRENGTHENING LOW-LEVEL WIND FIELDS AND DEEP LAYER MEAN
ENVIRONMENTAL FLOW IN EXCESS OF 40 KTS...POTENTIAL FOR DAMAGING WIND
GUSTS IN OR NEAR FAST MOVING STORMS WILL CONTINUE TONIGHT.
..KERR.. 07/19/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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