Hail and Damaging Wind in Washington, July 4, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
202 PM PDT TUE JUL 4 2006

.SYNOPSIS...SOUTHERLY FLOW OVER THE REGION WILL BRING A THREAT OF
THUNDERSTORMS TO THE AREA THROUGH THURSDAY. AS THE HIGH PRESSURE
RIDGE MOVES TO THE EAST TEMPERATURES WILL COOL SLOWLY...BUT WILL
REMAIN ABOVE AVERAGE FOR EARLY JULY.

&&

.DISCUSSION...
TONIGHT THROUGH THURSDAY NIGHT...SOUTHERLY FLOW CONTINUES OVER THE
AREA. RIDGE AXIS TO OUR EAST CONTINUES TO MOVE VERY SLOWLY EAST.
THIS ALLOWS FOR A GRADUAL COOLING AS WELL AS AN EASTWARD SHIFT OF
THE JET AND ASSOCIATED INSTABILITY.

THIS MORNINGS SHORT WAVE HAS
EXITED THE AREA INTO BC LEAVING A FAIRLY MOIST ATMOSPHERE IN ITS
WAKE. DEW POINTS IN THE MID 50S...INCLUDING THE HIGHER ELEVATIONS
LIKE STAMPEDE PASS...ARE RESULTING IN CAPES IN THE 1500-2500 J/KG
RANGE THIS AFTERNOON. LAPS ANALYSIS SHOWS THAT THE CAP HAS BEEN
REMOVED OVER MOST OF THE CASCADES AND THE NORTH- CENTRAL
MOUNTAINS...WITH ISOLATED CONVECTION BEGINNING TO FIRE IN THESE
AREAS. LACKING DYNAMIC SUPPORT ALOFT IM NOT EXPECTING FOR A
LARGE-SCALE CONVECTIVE OUTBREAK. BUT THE INSTABILITY SHOULD ALLOW
FOR SOME FAIRLY STRONG UPDRAFTS SO ITS NOT OUT OF THE QUESTION TO
SEE A FEW STORMS GO SEVERE IN THE NEXT FEW HOURS.

ANOTHER MINOR WAVE IN THE SOUTHERLY FLOW IS DUE TO REACH THE
SOUTHERN WA CASCADES LATE TONIGHT. DYNAMICS DONT LOOK AS STRONG
AS THIS MORNINGS WAVE...BUT STILL STRONG ENOUGH TO PROBABLY
INITIATE SOME LATE NIGHT/MORNING CONVECTION OVER THE CASCADES AND
POSSIBLY THE WESTERN BASIN. INSTABILITY AXIS MOVES EASTWARD A BIT ON
WEDNESDAY SO THE FOCUS FOR CONVECTION WILL SHIFT OVER THE CENTRAL
AND EASTERN PORTION OF MY AREA. BETTER SHEAR REMAINS TO THE WEST
SO THE CONVECTION STILL APPEARS TO BE MAINLY MOUNTAIN DRIVEN.

FOR THURSDAY A STRONGER NEGATIVE TILT WAVE MOVES OVER THE AREA.
INSTABILITY IS STRONGEST OVER THE PANHANDLE REGION WHILE THE BEST
DYNAMICS WILL BE OVER MY WESTERN SECTION. HARD TO PINPOINT THE
INTERSECTION OF THESE 2 AREAS AT THIS POINT. BUT THE POTENTIAL FOR
STRONG/SEVERE THUNDERSTORMS EXISTS FOR THURSDAY AFTERNOON...MAINLY
IN THE PANHANDLE.  RJ

FRIDAY THROUGH TUESDAY...GFS/ECMWF/CANADIAN/UKMET FORECAST MODELS
ARE IN GOOD AGREEMENT THROUGH THE WEEKEND...THEN DIVERGE FOR
MONDAY AND TUESDAY. THE FRIDAY THROUGH SUNDAY PERIOD WILL FEATURE
A CLOSED LOW IN THE GULF OF ALASKA WITH A WEST TO SOUTHWEST FLOW
ALOFT OVER THE AREA. SLIGHTLY COOLER ALONG WITH MUCH DRIER AND
STABLE AIR WILL BE OVER THE AREA FRIDAY BEHIND THE TROUGH PASSAGE
MENTIONED IN THE SHORT TERM DISCUSSION FOR THURSDAY. THEN OVER THE
WEEKEND THE FLOW ALOFT WILL BECOMING SOUTHWEST WITH RISING HEIGHTS
FOR WARMING BUT CONTINUED DRY. ON SUNDAY THE ATMOSPHERE WILL
MOISTEN UP SLIGHTLY...WHICH COMBINED WITH WARM TEMPERATURES WILL
LEAD TO MARGINAL INSTABILITY FOR A SLIGHT CHANCE OF THUNDERSTORMS
FOR THE EASTERN MOUNTAINS. THEN ON MONDAY AND TUESDAY MODELS SHOW
UPPER LOW IN GULF OF ALASKA MOVING INLAND...BUT HAVE LARGELY
DIFFERENT TRACKS. WILL FOLLOW 06Z GFS AND ECMWF MODELS WHICH
FAVOR A MORE CLIMATOLOGICAL SOLUTION...WITH THE LOW REMAINING
WELL NORTH INTO CENTRAL BRITISH COLUMBIA...RESULTING IN ONLY
SLIGHT COOLING FOR THE INLAND NORTHWEST. IF 12Z GFS AND 00Z
CANADIAN MODEL SOLUTIONS VERIFY...MORE SIGNIFICANT COOLING WOULD BE
POSSIBLE. JW

&&

.AVIATION...VFR CONDITIONS EXPECTED OUTSIDE OF THUNDERSTORM CORES
THROUGH 18Z WEDNESDAY. MOUNTAIN THUNDERSTORMS ONCE AGAIN EXPECTED
THIS AFTERNOON. THUNDERSTORMS ARE ALSO POSSIBLE OVER THE
WATERVILLE PLATEAU WHICH COULD AFFECT THE KEAT...KOMK OR KEPH TERMINALS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SPOKANE        68  92  62  85  56  83 /  20  10  20  20  20   0
COEUR DALENE  63  90  59  86  52  84 /  20  20  30  20  20   0
PULLMAN        60  89  57  84  52  82 /  20  10  30  20  20   0
LEWISTON       69  95  64  92  61  91 /  20  20  30  20  20   0
COLVILLE       58  92  57  88  48  85 /  20  30  20  40  20   0
SANDPOINT      54  93  58  81  52  81 /  20  30  40  40  30   0
KELLOGG        55  90  57  85  55  83 /  20  30  50  40  30   0
MOSES LAKE     68  95  63  89  56  87 /  20  10  10  10  10   0
WENATCHEE      71  92  65  87  61  86 /  20  10  10  10  10   0
OMAK           66  92  61  90  56  88 /  20  20  10  10  10   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&