[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 220042
SWODY1
SPC AC 220039

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0639 PM CST TUE NOV 21 2006

VALID 220100Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SRN ATLANTIC COAST...

EVENING WATER VAPOR IMAGERY SHOWS ANOMALOUSLY INTENSE UPPER LOW
CENTERED JUST OFF THE COAST OF NRN FL/GA WITH STRONG VORTICITY
MAXIMUM ROTATING NNWWD AROUND THE ERN/NERN PERIPHERY OF THIS LOW. 
DEEP-LAYER FORCING FOR ASCENT...COMPRISED OF DPVA AND LOW-LEVEL
WAA...ARE CONTRIBUTING TO EMBEDDED SCATTERED TSTMS FROM NEAR CRE TO
OAJ AS OF 0000Z.  THE MAJORITY OF THIS STORM ACTIVITY IS OCCURRING
NEAR AND W OF LOW-LEVEL BAROCLINIC ZONE LOCATED JUST OFF THE OUTER
BANKS WITHIN WEAKLY UNSTABLE ENVIRONMENT FOR ELEVATED PARCELS WITH
MUCAPES OF 200-300 J/KG AS OBSERVED BY 22/00Z MHX SOUNDING.

EXPECT THAT THE ONGOING LOW-LEVEL WAA WILL LIKELY CONTINUE TO BE THE
PRIMARY FORCING MECHANISM TO MAINTAIN ISOLATED TO SCATTERED TSTMS
OVERNIGHT MAINLY ALONG THE IMMEDIATE COAST.

...PACIFIC NW COAST TO NRN INTERMOUNTAIN REGION...

ISOLATED TSTMS HAVE BEEN OBSERVED THIS AFTERNOON AND EARLY EVENING
OVER CNTRL PARTS OF ID IN ASSOCIATION WITH LEAD SHORT WAVE TROUGH
TRANSLATING THROUGH THE NRN ROCKIES.  22/00Z BOI SOUNDING SHOWS THAT
STEEP LOW TO MID-LEVEL LAPSE RATES ARE LARGELY CONTRIBUTING TO
POCKETS OF WEAK INSTABILITY /MUCAPES OF 200-300 J PER KG/.  TSTMS
SHOULD TEND TO DIMINISH LATER THIS EVENING AS BOUNDARY LAYER COOLS
AND LAPSE RATES WEAKEN.

FARTHER TO THE W...MOIST ONSHORE FLOW IN THE LOW-LEVELS COUPLED WITH
COLD MID-LEVEL TEMPERATURES /-32 C AT 500 MB/ ARE CONTRIBUTING TO
STEEP LAPSE RATES AND WEAK CONVECTIVE INSTABILITY /PER 22/00Z
UIL/SLE SOUNDINGS/.  WATER VAPOR IMAGERY SUGGESTS THAT NEXT UPSTREAM
SHORT WAVE TROUGH IS ABOUT 100 NM W OF OTH WITH SOME OCEANIC
LIGHTNING ACTIVITY OBSERVED WITH THIS FEATURE. EXPECT THAT THE
THREAT OF ISOLATED...EMBEDDED TSTMS WILL INCREASE ALONG THE COAST
WITH THE ARRIVAL OF THIS IMPULSE LATE TONIGHT.

SOME SMALL HAIL/GRAUPEL MAY ACCOMPANY THE STRONGER CELLS...THOUGH
THE MARGINAL INSTABILITY WILL LIMIT ANY SEVERE THREAT.

..MEAD.. 11/22/2006

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