SWODY1
SPC AC 120041
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0741 PM CDT THU OCT 11 2007
VALID 120100Z - 121200Z
..NO SVR TSTM AREAS FORECAST...
..RI AND SERN MA...
VIGOROUS 996MB SURFACE LOW NEAR LONG ISLAND IS FORECAST TO TRACK
ACROSS RI AND ERN MA ON ITS WAY TO THE GULF OF MAINE BY EARLY FRIDAY
WITH CONVECTIVELY ACTIVE WARM CONVEYOR BELT NOW EXPANDING OVER CT
AND LONG ISLAND SOUND. STRONG DYNAMIC FORCING FOR ASCENT NEAR THE
LOW AND WARM FRONT WAS CURRENTLY COINCIDENT WITH A MOIST MARITIME
AIR MASS THAT HAS SO FAR REMAINED OFFSHORE. HIREZ WRF AND MESOSCALE
MODEL SOUNDINGS INDICATE THAT IT WILL BE DIFFICULT...BUT PERHAPS NOT
IMPOSSIBLE...FOR WEAK SURFACE-BASED DESTABILIZATION TO OCCUR INLAND
ACROSS RI AND SERN MA AS THE LOW TRACKS NEAR/OVER THESE AREAS
TONIGHT. GIVEN MAGNITUDE OF FORCING AND HIGH HELICITY ENVIRONMENT
NEAR THE LOW AND WARM FRONT...AN ISOLATED TORNADO CANNOT BE RULED
OUT IF WEAK SURFACE-BASED INVERSION CAN BE OVERCOME BY STORM SCALE
PROCESSES. MORE WIDESPREAD AIR MASS MODIFICATION/SEVERE THREAT
APPEARS UNLIKELY. GIVEN LIMITED TEMPORAL/AREAL EXTENT OF TORNADO
THREAT...AND UNCERTAINTY ABOUT FORMATION OF SURFACE-BASED
CONVECTION...ONLY A LOW FORECAST PROBABILITY IS WARRANTED FOR THIS
SCENARIO.
..KS...
NOCTURNAL TSTM INITIATION APPEARS POSSIBLE OVER KS BY EARLY FRIDAY
DUE TO FOLLOWING FACTORS... 1) INCREASING WARM AIR AND MOISTURE
ADVECTION FOCUSED ON THE NOSE OF MODEST LOW LEVEL JET...AND 2) WEAK
BACKGROUND ASCENT/DYNAMIC COOLING ASSOCIATED WITH TRAILING PORTION
OF SHORT WAVE IMPULSE CROSSING MIDDLE MISSOURI VALLEY. SLOPED AIR
PARCEL TRAJECTORIES WITH ORIGINS IN NARROW LOW LEVEL MOISTURE PLUME
SITUATED ACROSS THE SRN HIGH PLAINS SHOULD ACHIEVE AN LFC BETWEEN
800-700MB OVER CNTRL KS. MARGINALLY SEVERE HAIL APPEARS POSSIBLE
WITH ONE OR TWO OF THESE ELEVATED STORMS THROUGH DAYBREAK.
..WEST TX...
A COUPLE OF ROBUST SEVERE STORMS/SUPERCELLS ARE DEVELOPING SSWWD
ACROSS THE TRANS-PECOS THIS EVENING WITHIN MODERATELY UNSTABLE MOIST
AXIS ASSOCIATED WITH STALLED DEEP-LAYER FRONTAL ZONE. A NARROW
WINDOW OF SEVERE HAIL/WIND POTENTIAL WILL EXIST AS THESE CELLS MOVE
ACROSS VERY WARM AND UNPERTURBED AIR MASS FROM FORT STOCKTON SWD TO
THE RIO GRANDE. A DOWNWARD TREND IN INTENSITY SHOULD ENSUE WITHIN AN
HOUR OR SO BASED ON DIURNAL CYCLE AND LATEST GUIDANCE DEPICTING
LIMITED FORCING TO SUSTAIN A MORE WIDESPREAD SEVERE THREAT.
.CARBIN.. 10/12/2007
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