SWODY1
SPC AC 161239
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0739 AM CDT SAT AUG 16 2008
VALID 161300Z - 171200Z
...NO SVR TSTM AREAS FORECAST...
...NM/AZ AREA TODAY...
THE MID LEVEL CLOSED LOW OVER THE UT/WY/CO BORDER REGION WILL MOVE
LITTLE TODAY AS A BLOCKING RIDGE REMAINS IN PLACE FROM THE GREAT
BASIN TO THE NRN ROCKIES. BOUNDARY LAYER DEWPOINTS OF 55-60 F HAVE
SPREAD WWD ACROSS NM TO THE HIGH TERRAIN...WITH LESSER MOISTURE ON
THE PLATEAU TO THE W ACROSS NW NM AND NRN AZ. THE FOUR CORNERS AREA
WILL BE LOCATED ALONG THE SRN FRINGE OF THE CLOSED LOW WHERE WNWLY
MID LEVEL FLOW WILL REACH 30-40 KT. THIS MID LEVEL FLOW...IN
COMBINATION WITH LOW-LEVEL UPSLOPE FLOW ACROSS ERN/CENTRAL NM...WILL
RESULT IN SUFFICIENT BULK SHEAR FOR ORGANIZED STORM CLUSTERS...AS
WELL AS SUPERCELLS.
MAINTENANCE OF A MID LEVEL LAPSE RATE FEED FROM THE SRN GREAT BASIN
TO THE FOUR CORNERS...AND THE MODEST MOISTURE ALREADY PRESENT WILL
PROVIDE ENOUGH INSTABILITY FOR AT LEAST A MARGINAL SEVERE STORM
THREAT ACROSS NRN AZ INTO NM. ISOLATED LARGE HAIL AND DAMAGING
WINDS WILL BE THE MAIN THREATS THIS AFTERNOON/EVENING. COMPARED TO
FRIDAY...IT APPEARS THE SEVERE THREAT IN ERN NM WILL BE REDUCED SOME
AS A RESULT OF STABILIZATION FROM PRIOR CONVECTION.
...SRN NEW ENGLAND TODAY...
A PRONOUNCED MID LEVEL TROUGH NOW OVER NY/ERN PA WILL CONTINUE EWD
OVER NEW ENGLAND DURING THE DAY. COOL MID LEVEL TEMPERATURES /AOB
-16 C AT 500 MB/ AND MID LEVEL LAPSE RATES OF 6.5-7 C/KM WILL
COMBINE WITH DAYTIME HEATING AND RESIDUAL BOUNDARY LAYER DEWPOINTS
OF 56-60 F TO SUPPORT MUCAPE APPROACHING 1000 J/KG BY EARLY
AFTERNOON. VERTICAL SHEAR WILL NOT BE PARTICULARLY STRONG IN
PROXIMITY TO THE MID LEVEL THERMAL TROUGH OVER NEW ENGLAND THIS
AFTERNOON...BUT THE INSTABILITY AND RELATIVELY COOL TEMPERATURE
PROFILES SHOULD BE SUFFICIENT FOR A FEW STORMS WITH MARGINALLY
SEVERE HAIL AND GUSTY OUTFLOW WINDS AROUND MIDDAY THROUGH MID
AFTERNOON.
...UPPER MI/NRN WI THIS AFTERNOON/EVENING...
A LOW-AMPLITUDE SHORTWAVE TROUGH WILL PROGRESS SEWD FROM WRN ONTARIO
TO UPPER MI BY LATE AFTERNOON...AROUND THE SWRN PERIPHERY OF A
LARGER CLOSED LOW OVER HUDSON BAY. THE MID LEVEL TROUGH WILL BE
ACCOMPANIED BY A DIFFUSE SURFACE TROUGH. THOUGH BOUNDARY LAYER
DEWPOINTS WILL BE LIMITED TO THE 50S AND MID LEVEL LAPSE RATES WILL
BE RATHER MODEST /ROUGHLY 6.5 C/KM/...DAYTIME HEATING SHOULD SUPPORT
THE DEVELOPMENT OF MUCAPE VALUES OF 500-1000 J/KG. WIDELY SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP AROUND MID AFTERNOON AND
SPREAD SEWD WITH THE MID LEVEL TROUGH. MARGINAL BULK SHEAR AND
INSTABILITY COULD BE SUFFICIENT FOR ISOLATED STORMS WITH HAIL AND
GUSTY WINDS LATER THIS AFTERNOON/EVENING.
..THOMPSON/LEVIT.. 08/16/2008
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