Thursday, October 11, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 111618
SWODY1
SPC AC 111614

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1114 AM CDT THU OCT 11 2007

VALID 111630Z - 121200Z

..NO SVR TSTM AREAS FORECAST...

..SRN HIGH PLAINS...
LOW AMPLITUDE...SLOW MOVING IMPULSES ARE NOW MOVING SSEWD ACROSS FAR
WRN TX AND SERN NM THIS MORNING. VISIBLE IMAGERY INDICATES NEARLY
CLEAR SKIES OVER THE REGION...AND WILL SUPPORT SEASONABLY WARM
AFTERNOON TEMPERATURES TODAY WITH HIGHS IN THE MID TO UPPER 80S.
THIS WILL OCCUR ALONG WRN PERIPHERY OF POLAR CONTINENTAL AIR IN
PLACE FARTHER EAST OVER THE SRN PLAINS THIS MORNING...WHERE SSELY
LOW LEVEL WINDS WILL SUSTAIN AN AXIS OF 60-65F SURFACE DEW POINTS
OVER WRN TX. FORECAST SOUNDINGS ALONG WITH MODIFIED 12Z OBSERVED
SOUNDINGS SUGGEST MLCAPE AROUND 2000 J/KG WILL BE COMMON BY THE MID
TO LATE AFTERNOON OVER SWRN TX/W-CENTRAL TX INTO FAR SERN NM.
PRIMARY WEAKNESSES FOR SUSTAINED/ORGANIZED STORMS WILL BE THE
MARGINAL DEEP LAYER SHEAR AND THE WEAKENING LARGE SCALE SUPPORT AS
MID LEVEL IMPULSE NOW OVER SERN NM DAMPENS OUT. HOWEVER...DEGREE OF
INSTABILITY...STEEP LAPSE RATES AND STRONG VEERING IN THE LOWEST FEW
KM MAY STILL SUPPORT AN ISOLATED STRONG TO SEVERE THUNDERSTORM...AND
POSSIBLY A SUPERCELL...INTO THE EARLY TO MID EVENING.

..MID ATLANTIC COAST...
NARROW AREA OF MARGINAL MLCAPE WILL PERSIST OVER PORTIONS OF NJ
WHERE 60F+ DEW POINTS ARE PERSISTING INVOF SURFACE LOW AND
ASSOCIATED COLD FRONT FORECAST TO MOVE EWD OFF THE NJ COAST THIS
AFTERNOON. SHEAR PARAMETERS REMAIN QUITE FAVORABLE FOR ROTATING
STORMS...IF ACTIVITY CAN ROOT INTO THE BOUNDARY LAYER THIS
AFTERNOON. STORMS WILL BE LOW TOPPED GIVEN THE MARGINAL INSTABILITY
AND LACK OF MID LEVEL LAPSE RATES. HOWEVER...APPEARS A
CONDITIONAL/LOW PROBABILITY RISK IS WARRANTED FOR A BRIEF-LIVED
DAMAGING WIND OR TORNADO POSSIBILITY. ANY SEVERE THREAT WILL LIKELY
DIMINISH WITH NWD EXTENT INTO LONG ISLAND/SRN NEW ENGLAND GIVEN
STRONGER CAPPING AND WEAKENING INSTABILITY.

..CENTRAL HIGH PLAINS...
MODELS ARE CONSISTENT IN DEVELOPING A SEWD MOVING AREA OF ELEVATED
MOIST CONVECTION OUT OF NWRN KS LATER TONIGHT ALONG NOSE OF 35+ KT
SLY LLJ. FORECAST SOUNDINGS FOR THIS AREA INDICATE MUCAPE MAY
EXCEED 1000 J/KG WITH 35-45 KT EFFECTIVE SHEAR...SUGGESTING HAIL MAY
ACCOMPANY THE STRONGER CORES.

.EVANS/GUYER.. 10/11/2007

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