[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 220503
SWODY1
SPC AC 220501

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1101 PM CST TUE NOV 21 2006

VALID 221200Z - 231200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A STRONG AND COMPACT UPPER LOW WILL SLOWLY LIFT NEWD ALONG THE SERN
COAST THROUGH THE PERIOD. AHEAD OF THIS FEATURE...A SFC FRONTAL
BOUNDARY WILL REMAIN NEARLY STATIONARY ALONG THE OUTER BANKS NWD
JUST OFF THE MID ATLANTIC COAST OF NJ. THE COMBINATION OF MODEST
VERTICAL MOTION AND INSTABILITY SHOULD SUPPORT ISOLATED TO SCATTERED
TSTMS ALONG AND EAST OF THIS BOUNDARY THROUGH TONIGHT. ELSEWHERE
ACROSS THE NATION...WARM AND MILD CONDITIONS CAN BE EXPECTED ACROSS
THE PLAINS STATES UNDER THE INFLUENCE OF MID/UPPER RIDGING. FURTHER
WEST...ANOTHER STRONG UPPER TROUGH WILL MOVE INTO THE PAC NW DURING
THE DAY AND INTO THE NRN ROCKIES WED NIGHT. THE COMBINATION OF
MODEST UPSLOPE FLOW AND COLD MID LEVEL TEMPERATURES WILL SUPPORT
ISOLATED TSTMS OVER WRN WA/ORE AS WELL AS PORTIONS OF THE NRN
ROCKIES.


...OUTER BANKS OF NC...
THE FRONTAL BOUNDARY PRESENTLY DRAPED ACROSS THE AREA WILL REMAIN
NEARLY STATIONARY THROUGH DAYTIME HRS AS THE SFC/UPPER LOW MOVES
SLOWLY NNEWD. COLDER MID LEVEL TEMPERATURES  /-22 DEG C AT 500 MB/
LOCATED OFF THE EAST COAST OF FLA EARLY THIS MORNING WILL ROTATE
ACROSS THE AREA DURING PEAK HEATING. SUFFICIENT INSTABILITY /MUCAPE
FROM 500-750 J/KG/ COUPLED WITH LOW-MID LEVEL MODERATE VERTICAL
MOTION EAST OF THE STATIONARY BOUNDARY SHOULD SUPPORT ISOLATED/SCT
TSTM DEVELOPMENT. DESPITE THE PRESENCE OF A MID LEVEL DRY SLOT OVER
THE REGION...THERE SHOULD BE WIDESPREAD LOW CLOUD COVER GIVEN THE
MOIST LOW LEVEL WARM ADVECTION PROFILE. IF LESS LOW CLOUD COVER
DEVELOPS THAN PRESENTLY EXPECTED...SLIGHTLY GREATER INSTABILITY
/MUCAPES OVER 1000 J/KG/ WOULD BE REALIZED SUPPORTING MARGINALLY SVR
HAIL IN THE STRONGEST TSTMS. GIVEN THE LOW CONFIDENCE IN THIS
SCENARIO...WE WILL NOT INTRODUCE 5 PERCENT HAIL PROBS FOR THIS AREA
ATTM.

...PAC NW/NRN ROCKIES...
A LARGE POCKET OF COLD MID LEVEL TEMPERATURES...EVIDENT BY VIS/IR
SATELLITE IMAGERY...EXISTED SEVERAL HUNDRED MILES OFF THE PAC NW
COAST. THIS AREA WAS IN ASSOCIATION WITH A STRONG UPPER LOW/VORT
LOBE ROTATING AROUND A BROADER UPPER TROUGH LOCATED OVER THE NERN
PACIFIC. AS THIS VORT LOBE/TROUGH MOVES TOWARDS THE PAC NW COAST
DURING THE AFTERNOON...SUFFICIENTLY STRONG UPSLOPE FLOW COMBINED
WITH STEEPENING MID LEVEL LAPSE RATES /7.5-8 DEG C/KM/ WILL SUPPORT
SCATTERED TSTMS OVER PORTIONS OF WRN ORE/WA. ALONG WITH LOW WBZ
HEIGHTS...SUB-SVR SMALL HAIL/GRAUPEL IS POSSIBLE WITH THE STRONGEST
TSTMS IN LOWER ELEVATIONS. DESPITE BEING AFTER DARK...ISOLATED TSTMS
ARE ALSO POSSIBLE IN THE STRONG UPSLOPE REGIME/STEEP LAPSE RATE
ENVIRONMENT JUST AHEAD OF UPPER TROUGH OVER PORTIONS OF THE NRN
ROCKIES BETWEEN 23/06-12Z.

..CROSBIE/MEAD.. 11/22/2006

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