[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 221640
SWODY1
SPC AC 221638

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1138 AM CDT SAT JUL 22 2006

VALID 221630Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SRN NEW ENGLAND TO MID
ATLANTIC STATES...

...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF UPPER MISSISSIPPI
VALLEY...

...NERN U.S...
SEASONABLY DEEP UPPER TROUGH ERN U.S.  WITH VERY LARGE UPPER HIGH IN
THE WEST. THE S/WV TROUGH DEPICTED ON W/V IMAGERY AND HEIGHT FALLS
AT 12Z IS LIFTING NEWD ACROSS NY/PA ATTM WITH ASSOCIATED BAND OF
STRONGER WIND FIELDS SPREADING ACROSS NERN U.S. AHEAD OF S/WV THIS
AFTERNOON AND EVENING. SURFACE LOW AT 15Z NERN PA IS GRADUALLY
DEEPENING AS IT TRACKS NEWD TO SERN NY LATER THIS AFTERNOON AND NRN
VT/NH LATER TONIGHT.  A VERY WARM AND MOIST AIRMASS IS SPREADING
NEWD IN THE 30-35KT SWLY FLOW AHEAD OF LOW AND THE WEAK COLD FRONT
WHICH TRAILS SWWD TO NRN GULF STATES.

SHEAR PROFILES ARE IN PLACE TO SUPPORT SEVERE THUNDERSTORMS AND
SUPERCELLS AHEAD OF SURFACE LOW FROM ERN DELMARVA NEWD INTO SRN NEW
ENGLAND THIS AFTERNOON AND EVENING.  THE PRIMARY CAVEAT IS SURFACE
HEATING AS EXTENSIVE CLOUDINESS THIS AM IS ONLY SLOWLY THINNING. 
HOWEVER WITH ONLY WEAK CIN...AND HEATING NOW SHOWING E OF
APPALACHIANS AS FAR N AS SRN PA...TEMPERATURES SHOULD RISE THRU THE
80S NWD THRU SERN NY BY MID AFTERNOON. THIS WILL RESULT IN MLCAPES
INCREASING TO NEAR 2000 J/KG  AS FAR N AS NJ/ERN NY AND 1000-1500
J/KG SRN NEW ENGLAND LATE THIS AFTERNOON.

SURFACE BASED STRONG/SEVERE THUNDERSTORMS WILL DEVELOP BY 18Z AHEAD
OF SURFACE LOW AND ALONG LEE TROUGH LOCATED TO E OF APPALACHIANS. 
PRIMARY THREAT WILL BE DAMAGING WINDS AS STORMS FORM INTO CLUSTERS
AND LINES...HOWEVER 20-25KT OF SFC-1KM SHEAR AND LOW LCLS ALSO
SUPPORT SUPERCELLS.  GREATEST TORNADIC SUPERCELL POTENTIAL WOULD BE
IN ENHANCED LOW LEVEL CONVERGENCE AHEAD OF LOW AND VICINITY THE
SUBTLE WARM FRONT EXTENDING EWD THRU SRN NEW ENGLAND AND ALONG THE
SURFACE LEE TROUGH THAT WILL BE LOCATED VICINITY PA/NJ BORDER LATER
THIS AFTERNOON.

...MID ATLANTIC/GULF COAST STATES...
WHILE SHEAR WILL BE WEAKER ACROSS THIS AREA...THE AIR MASS IS VERY
MOIST AND POTENTIALLY QUITE UNSTABLE.  GOOD HEATING UNDERWAY MUCH OF
THE REGION AHEAD OF COLD FRONT WHICH HAS PROGRESSED TO NRN AL AND
MS.  THUNDERSTORMS WILL BE COMMON ALONG AND AHEAD OF COLD FRONT BY
MID AFTERNOON AS MLCAPES CLIMB TO 2000 J/KG OR MORE.  WITH DEEP
LAYER SHEAR GENERALLY LESS THAN 20KT...STORM MODE SHOULD BE
PULSE/MULTICELL.  PRIMARY SEVERE THREAT WILL BE WET MICRO-BURSTS.
SEVERE OCCURRENCE SHOULD BE GREATEST CAROLINAS WHERE SHEAR IS
GREATER...DECREASING TO MORE ISOLATED COVERAGE GULF STATES.

...UPPER MS VALLEY...
WEAK IMPULSE EMBEDDED IN NLY FLOW NOTED ON W/V IMAGERY DROPPING SWD
THRU WI TODAY. OVERALL THE SHEAR OF 30KT OR LESS SUPPORT MULTICELL
CONVECTIVE MODE.  WITH FREEZING LEVELS NEAR 10K FT AND AFTERNOON
HEATING GENERATING SBCAPE TO 1000-1500 J/KG A FEW SEVERE
THUNDERSTORMS ARE LIKELY.  PRIMARY THREAT WILL BE LARGE HAIL WITH
THE EARLIER SLIGHT RISK AREA BEING SHIFTED EWD INTO WI WHERE  TRACK
OF UPPER SYSTEM IS LOCATED.

...SWRN U.S...
VERY TO EXTREMELY HOT CONDITIONS CONTINUE UNDER LARGE UPPER HIGH. 
MOISTURE HAS CONTINUED TO INCREASE NWWD THRU W COAST STATES WITH
PW/S GENERALLY 1.25 TO 1.5 NOTED.  WITH VERY STEEP LAPSE
RATES...THUNDERSTORMS WILL DEVELOP OVER HIGHER TERRAIN FROM NM/AZ
NWWD THRU INTERIOR CA/WRN NV.  ISOLATED SEVERE DOWNBURSTS ARE LIKELY
AS STORMS DRIFT OFF MOUNTAINS LATER THIS AFTERNOON WITH MARGINALLY
SEVERE HAIL ALSO POSSIBLE PRIMARILY OVER HIGHER TERRAIN.

..HALES/GRAMS.. 07/22/2006