[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 252239
SWOMCD
SPC MCD 252238 
IDZ000-NVZ000-ORZ000-260115-

MESOSCALE DISCUSSION 1777
NWS STORM PREDICTION CENTER NORMAN OK
0538 PM CDT SUN JUL 25 2004

AREAS AFFECTED...PORTIONS SERN AND EXTREME E-CENTRAL ORE...SWRN AND
W-CENTRAL ID...EXTREME NRN NV

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 252238Z - 260115Z

WIDELY SCATTERED TSTMS WILL CONTINUE TO DEVELOP -- PRIMARILY IN
AREAS OF STRONGEST OROGRAPHIC ASCENT...THEN MOVE GENERALLY EWD TO
SEWD ACROSS PORTIONS ERN ORE AND WRN ID...THROUGH AT LEAST 01Z. 
POTENTIAL EXISTS FOR HAIL AND STRONG-SEVERE GUSTS FROM MOST INTENSE
TSTMS. LOOSELY ORGANIZED BAND OF CONVECTION ALSO SHOULD MOVE SLOWLY
NWD FROM EXTREME NRN NV INTO UNSTABLE AIR MASS OVER SRN ID.  WITH
BRIEF/ISOLATED SEVERE THREAT APPEARS TOO ISOLATED ATTM FOR
WW...THOUGH SOME LOCALLY DAMAGING WIND MAY OCCUR.

AIR MASS CONTINUES TO DESTABILIZE ACROSS MUCH OF DISCUSSION AREA
FROM JUST S OF NRN NV BORDER NWD ACROSS PORTIONS SRN/WRN ID AND ERN
ORE.  ANIMATED VIS IMAGERY INDICATES TWO SMALL MIDLEVEL
VORTICES...EACH MOVING NEWD 15-20 KT --
1. WEAKENING OVER PORTIONS ELMORE/CAMAS/BLAINE COUNTIES ID...MOVING
OUT OF SNAKE RIVER VALLEY TOWARD MT BORDER...
2. OVER MALHEUR COUNTY ORE...HEADING TOWARD LOWER PORTIONS SNAKE
RIVER VALLEY IN WRN-MOST ID.  THIS FEATURE ALSO IS EVIDENT IN UPPER
LEVELS ON MOISTURE CHANNEL IMAGERY.

DESTABILIZATION ALOFT ASSOCIATED WITH LATTER FEATURE WILL BE
JUXTAPOSED OVER NEXT SEVERAL HOURS WITH MOST INTENSE LOW LEVEL
HEATING -- OVER RELATIVELY LOW ELEVATIONS NEAR RIVER.  BOTH ETA AND
RUC ARE NOT HEATING/MIXING NEAR SFC AIR MASS OVER THIS REGION
STRONGLY ENOUGH AND THEREFORE ARE UNDERESTIMATING BUOYANCY. 
ACCORDINGLY MODIFIED MODEL SOUNDINGS AND RAOBS WITH NOWCAST SFC
TEMPS/DEW POINTS IN REGION SUGGEST LOW-MIDLEVEL LAPSE RATES NEAR DRY
ADIABATIC...WITH MLCAPE COMMONLY IN 1000-1500 J/KG RANGE...ATOP DEEP
BOUNDARY LAYERS WITH INVERTED-V TYPE THERMODYNAMIC PROFILES. 
CONSIDERABLE SUBCLOUD EVAPORATION POTENTIAL SUGGESTS MAINTENANCE OF
BOTH HAIL AND DOWNDRAFT INTENSITY TO SFC...ESPECIALLY OVER LOWER
ELEVATIONS WHERE MIXING EFFECTS ARE DEEPEST.

..EDWARDS.. 07/25/2004

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PIH...MSO...BOI...LKN...PDT...MFR...

42401472 42061481 41701573 41671706 41851848 42221979
42382013 42662037 44381902 45031731 46091612 46171563
45671494 43301521 42671494 

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