Sunday, August 17, 2008

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 171629
SWODY1
SPC AC 171627

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1127 AM CDT SUN AUG 17 2008

VALID 171630Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
PARTS OF NORTHERN CA AND CENTRAL ORE...

...CA/ORE...
LARGE UPPER RIDGE IS PRESENT THIS MORNING OVER THE INTERMOUNTAIN
WEST...WITH SERIES OF WEAK SHORTWAVE TROUGHS LIFTING NORTHWARD ALONG
THE CA/ORE COAST. LATEST SURFACE ANALYSIS SHOWS DEWPOINTS OVER
WESTERN ORE AND NORTHEAST CA IN THE MID 50S TO LOWER 60S...WHICH
WILL YIELD AFTERNOON SBCAPE VALUES OF AROUND 1000-1500 J/KG.
SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP IN THE HIGHER
TERRAIN NEAR THE CA/ORE BORDER LATER TODAY AND TRACK NORTHWARD INTO
CENTRAL ORE. FORECAST SOUNDINGS SUGGEST THE RISK OF HAIL AND
GUSTY/DAMAGING WINDS IN STRONGER CELLS.

...AZ/NM/CO/TX...
PERSISTENT UPPER LOW REMAIN OVER CENTRAL CO TODAY...WITH BAND OF
MODERATELY STRONG WEST-NORTHWEST MID LEVEL FLOW ACROSS THE SOUTHWEST
STATES. SLIGHTLY DRIER MID LEVEL AIR HAS ROTATED ACROSS THIS
REGION...WHICH WILL LIKELY RESULT IN GREATER DAYTIME
HEATING/DESTABILIZATION OVER THE MOUNTAINS OF AZ/NM AND SOUTHERN CO.
WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED ONCE AGAIN THIS
AFTERNOON AND EVENING WITH A RISK OF DAMAGING WINDS AND HAIL.
ACTIVITY MAY SPREAD EASTWARD INTO WEST TX BEFORE WEAKENING LATER
THIS EVENING.

...GREAT LAKES...
A STRONG SHORTWAVE TROUGH IS DIGGING SOUTHEASTWARD ACROSS
SASKATCHEWAN/MANITOBA TOWARD THE WESTERN GREAT LAKES. FAVORABLE
DEEP LAYER VERTICAL SHEAR AND INSTABILITY WILL BE PRESENT AHEAD OF
THIS TROUGH...LEADING TO SCATTERED STRONG/SEVERE STORMS MAINLY OVER
PARTS OF ONTARIO TODAY. NEVERTHELESS...TRAILING END OF CONVECTIVE
ACTIVITY MAY AFFECT PARTS OF NORTHERN MN THIS AFTERNOON.
ALSO...ISOLATED STRONG STORMS MAY FORM OVER LOWER MI DURING PEAK
HEATING PERIOD. LACK OF LOW LEVEL FORCING OVER THESE REGIONS
SUGGEST THAT AREAL COVERAGE OF STRONG STORMS DOES NOT WARRANT A
SLIGHT RISK AT THIS TIME.

...FL/GA/SC...
WEAK MID LEVEL VORT MAX IS CURRENTLY OVER WESTERN NC AND WILL DRIFT
EASTWARD TOWARD THE COAST TODAY. THE ASSOCIATED POOL OF COOLER MID
LEVEL TEMPERATURES WILL HELP TO DESTABILIZE MUCH OF SC/GA AND
NORTHERN FL LATER THIS AFTERNOON...ESPECIALLY WHERE DAYTIME HEATING
IS MAXIMIZED. PRESENT INDICATIONS ARE THAT SCATTERED THUNDERSTORMS
MAY DEVELOP ALONG SEABREEZES OVER THIS AREA WITH THE RISK OF GUSTY
WINDS AND HAIL IN STRONGER CELLS. ORGANIZED SEVERE STORMS ARE NOT
ANTICIPATED.

...FL KEYS...
TROPICAL STORM FAY WILL NOT BEGIN TO APPROACH THE FL KEYS UNTIL THE
DAY2 PERIOD. HOWEVER...STRENGTHENING WIND FIELDS NEAR OUTER BANDS
OF SYSTEM MAY INCREASE THE RISK OF AN ISOLATED TORNADO...MAINLY
AFTER 06Z.

..HART/JEWELL.. 08/17/2008

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