[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 182000
SWODY1
SPC AC 181958

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0258 PM CDT TUE JUL 18 2006

VALID 182000Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM NEW ENGLAND ACROSS THE
MIDDLE ATLANTIC STATES INTO THE MIDDLE MS VALLEY...

...NERN STATES INTO THE MIDDLE MS VALLEY...
UPPER TROUGH FROM QUEBEC SWWD ACROSS THE LOWER GREAT LAKES IS
EXPECTED TO CONTINUE MOVING EWD THROUGH TONIGHT.  ERN PART OF THE
ASSOCIATED SURFACE COLD FRONT CURRENTLY FROM SRN ME SWWD INTO
CENTRAL PA AND CENTRAL IL WILL MOVE SEWD ACROSS THE MID ATLANTIC
STATES...WHILE WRN PORTION OF THE FRONT MOVES MORE SLOWLY ACROSS THE
OH VALLEY.  A VERY WARM/MOIST LOW LEVEL AIR MASS IS PRESENT
ALONG/AHEAD OF THE FRONT WITH SURFACE TEMPERATURES GENERALLY IN THE
UPPER 80S/LOWER 90S AND DEW POINTS IN THE UPPER 60S TO LOWER
70S...WITH HIGHER DEW POINTS IN THE MID/UPPER 70S NOTED OVER PARTS
OF IL/ERN MO.  THE HIGH THETA-E AIR MASS IS CONTRIBUTING TO A
MODERATELY TO VERY UNSTABLE ENVIRONMENT WITH MLCAPE RANGING FROM
1500-2500 J/KG FROM SRN NEW ENGLAND ACROSS THE MIDDLE ATLANTIC
STATES INTO THE OHIO VALLEY TO 3000-4000 J/KG IN THE MIDDLE MS
VALLEY.

STRONG/SEVERE THUNDERSTORMS HAVE DEVELOPED OVER NRN NEW
ENGLAND...WITH ADDITIONAL CLUSTERS OVER PA...ERN WV...AND WRN OH. 
VISIBLE SATELLITE IMAGERY INDICATES ENHANCED CU/TCU ALONG THE FRONT
CENTRAL PA INTO EAST CENTRAL OH SUGGESTING NEW THUNDERSTORMS MAY
DEVELOP SOON ACROSS THIS AREA. ALTHOUGH STRONGER DEEP LAYER SHEAR
OF 30-40 KT EXISTS FROM NY INTO NEW ENGLAND...MODERATE SHEAR OF
20-30 KT ACROSS THE DELMARVA/PA/OH AREA SHOULD BE SUFFICIENT TO
ENHANCE CONVECTIVE ORGANIZATION AND SUPPORT A FEW SEVERE STORMS
CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND LARGE HAIL INTO THE
EVENING HOURS.

FARTHER WEST...VISIBLE IMAGERY SHOWS A DEVELOPING CU FIELD NEAR A
SURFACE LOW OVER SOUTH CENTRAL IL.  CONTINUED HEATING COUPLED WITH
HIGH SURFACE DEW POINTS AND DRYING ALOFT ARE COMBINING TO PRODUCE
VERY UNSTABLE CONDITIONS.  HOWEVER...THE DRYING/SUBSIDENCE ALOFT
ALSO APPEARS TO BE INHIBITING DEEP CONVECTIVE INITIATION ATTM. AS
THE CAP CONTINUES TO WEAKEN...A FEW PARCELS MAY REACH THE LFC WITH
SUBSEQUENT RAPID THUNDERSTORM DEVELOPMENT POSSIBLE.  NWLY MID LEVEL
WINDS OF 25 KT WILL PROVIDE SUFFICIENT DEEP LAYER SHEAR FOR SEVERE
THUNDERSTORMS TO DEVELOP.  VERY LARGE HAIL AND DAMAGING WIND GUSTS
WILL BE POSSIBLE WITH ANY PERSISTENT UPDRAFTS THAT CAN DEVELOP.

...GULF COAST REGION...
SCATTERED CONVECTION HAS DEVELOPED FROM AL AND EXTREME WRN GA SWWD
ACROSS MS/LA INTO SERN TX.  20-30 DEG F TEMPERATURE/DEW POINT
SPREADS AT THE SURFACE COUPLED WITH STEEP LOW LEVEL LAPSE RATES AND
PRONOUNCED DRYING IN THE MID/UPPER LEVELS INDICATES POTENTIAL FOR A
FEW WET MICROBURSTS TO OCCUR.

...PARTS OF CA/WRN NV...
VISIBLE IMAGERY SHOWS A WELL-DEFINED MESOSCALE CONVECTIVE VORTEX
MOVING NWWD INTO CENTRAL CA.  THIS MAY ENHANCE THUNDERSTORM
DEVELOPMENT ACROSS THIS REGION LATER THIS AFTERNOON AND EVENING.

...NRN PLAINS...
WEAK ELEVATED CONVECTION HAS MOVED EWD ACROSS NRN SD...WITH CLEAR
SKIES AND STRONG INSOLATION OCCURRING IN ITS WAKE OVER THE NRN
PLAINS.  AN ELEVATED MOISTURE RETURN WILL INCREASE TONIGHT IN
RESPONSE TO A STRENGTHENING SOUTHERLY LOW LEVEL JET.  THIS SUGGESTS
POTENTIAL FOR ELEVATED THUNDERSTORMS TO DEVELOP DURING THE OVERNIGHT
HOURS OVER PARTS OF THE DAKOTAS WHICH MAY BE CAPABLE OF PRODUCING
HAIL WITH STRONGER STORMS.  CONVECTIVE COVERAGE APPEARS TO BE TOO
LIMITED TO WARRANT A SLIGHT RISK AREA.

..WEISS.. 07/18/2006