[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 221233
SWODY1
SPC AC 221231

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0731 AM CDT SAT JUL 22 2006

VALID 221300Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM NORTHERN AL/GA...ACROSS
THE MID ATLANTIC REGION...INTO SOUTHERN NEW ENGLAND...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF MN/IA...

MORNING SATELLITE LOOPS SHOW WELL-DEFINED UPPER TROUGH ROTATING
THROUGH THE OH VALLEY. THIS SYSTEM WILL BRING RATHER STRONG WIND
FIELDS AND LIFT TO MUCH OF THE NORTHEAST AND MID ATLANTIC STATES
TODAY...ALONG WITH A RISK OF SEVERE THUNDERSTORMS WHERE DAYTIME
HEATING CAN OCCUR.

...SOUTHERN NEW ENGLAND INTO PA/NJ...
SURFACE LOW NOW OVER NORTHWESTERN PA IS FORECAST TO DEEPEN AND TRACK
EASTWARD ACROSS PA/NY AND INTO WESTERN NEW ENGLAND TODAY.  A VERY
MOIST AIR MASS WILL BE PRESENT IN WARM SECTOR OF LOW WITH DEWPOINTS
IN THE 70S...BUT ALSO WITH SCATTERED CLOUD COVER AND SHOWERS.  MODEL
FORECAST SOUNDINGS FROM EASTERN PA/NJ NORTHWARD ACROSS SOUTHERN NEW
ENGLAND SUGGEST UNSEASONABLY STRONG LOW/MID LEVEL WIND FIELDS WILL
DEVELOP BY AFTERNOON /6KM SHEAR OF 35-45 KNOTS AND 0-3KM HELICITY OF
150-250 M2/S2/...FAVORABLE FOR SUPERCELL STORMS AND EVEN ISOLATED
TORNADOES.  HOWEVER...LACK OF STRONG HEATING WILL LIKELY MITIGATE
OVERALL SEVERE THREAT ACROSS THIS REGION.  

PRESENT INDICATIONS ARE THAT ONGOING THUNDERSTORM ACTIVITY OVER
PA/NY WILL PROGRESS EASTWARD...WITH SOME INTENSIFICATION POSSIBLE
ALONG THE SOUTHEAST FRINGE OF STORMS ACROSS EASTERN PA/NJ AND
SOUTHEAST NY.  THESE STORMS WILL MOVE NORTHEASTWARD INTO SOUTHERN
NEW ENGLAND BY LATE AFTERNOON. SURFACE TEMPERATURES IN THE LOWER
80S WILL BE SUFFICIENT FOR SURFACE-BASED STORMS AND A RISK OF
SUPERCELLS.  NORTHWARD EXTENT OF SEVERE THREAT WILL BE DICTATED BY
CLOUD COVER AND ASSOCIATED SURFACE HEATING.  DAMAGING WINDS AND
ISOLATED TORNADOES APPEAR TO BE THE MAIN THREATS IN THIS REGION.

...MID ATLANTIC REGION...
MORNING SHOWERS ARE EXPECTED TO DISSIPATE SOMEWHAT BY EARLY
AFTERNOON...ALLOWING MODERATE DAYTIME HEATING FROM NORTHERN NC INTO
MD/DE. SCATTERED THUNDERSTORMS WILL LIKELY DEVELOP OVER THE
MOUNTAINS OF WESTERN NC/VA AND MOVE EASTWARD THIS AFTERNOON. 
SUFFICIENT WIND FIELDS ALOFT AND MODERATE INSTABILITY WILL PROMOTE A
RISK OF DAMAGING WINDS IN STRONGER CELLS.

...CAROLINA COAST...
STRONG HEATING OVER COASTAL NC/SC WILL ALLOW SEA BREEZE TO MOVE
ONSHORE LATER THIS AFTERNOON.  INTERACTION OF SEA BREEZE WITH
CONVECTIVE OUTFLOWS FROM OVERNIGHT AND AFTERNOON THUNDERSTORMS MAY
RESULT IN ISOLATED SEVERE STORMS CAPABLE OF DAMAGING WINDS.  THREAT
SHOULD DIMINISH RAPIDLY AFTER SUNSET.

...MN/IA...
RELATIVELY STRONG NORTHWEST FLOW PATTERN WILL BE PRESENT TODAY OVER
THE MIDWEST.  FULL SUNSHINE AND STEEP LAPSE RATES WILL ALLOW AIRMASS
TO BECOME MODERATELY UNSTABLE BY LATE AFTERNOON...DESPITE SURFACE
DEWPOINTS ONLY IN THE LOW 60S. PRESENT INDICATIONS ARE THAT
ISOLATED THUNDERSTORMS WILL DEVELOP OVER SOUTHEAST MN BY LATE
AFTERNOON...SPREADING SOUTHWARD INTO IA DURING THE EVENING.  BRIEF
SUPERCELLS ARE POSSIBLE WITH A RISK OF HAIL AND GUSTY WINDS.

..HART/CROSBIE.. 07/22/2006