000
FXUS66 KOTX 111128 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
428 AM PDT SAT OCT 11 2008
.SYNOPSIS...
AN UNSEASONABLY COOL AND DRY AIR MASS WILL DOMINATE THE INLAND
NORTHWEST THROUGH THE REMAINDER OF THE WEEKEND. LOCALLY BREEZY
CONDITIONS WILL REDEVELOP TODAY BUT THE PRESSURE GRADIENT WILL NOT
BE QUITE AS STRONG AS FRIDAY. EVEN LIGHTER WINDS CAN BE EXPECTED ON
SUNDAY.
&&
.DISCUSSION...
UPDATED AVIATION DISCUSSION.
TODAY AND TONIGHT...NO SIGNIFICANT CHANGES TO THE PREVIOUS FORECAST
AS A CHILLY AND VERY DRY AIR MASS HAS TAKEN UP RESIDENCE. LARGE
545 DAM 500MB LOW CENTERED JUST NORTH OF LAS VEGAS EARLY THIS
MORNING APPEARS TO HAVE BOTTOMED OUT AND WILL BEGIN TO SLOWLY LIFT
NEWD TOWARD THE CENTRAL ROCKIES THIS PERIOD. WHILE THE LOW ITSELF
IS FAR REMOVED FROM OUR AREA...A WELL-DEFINED MID-LEVEL DEFORMATION
ZONE EXTENDING NORTH FROM THE LOW CENTER WILL TAKE ON MORE OF A
N-S ORIENTATION TODAY AND REMAIN IN CLOSE PROXIMITY TO OUR
SOUTHEAST CORNER FOR THE NEXT 24-36 HOURS. THE AIR MASS REMAINS
TOO DRY TO SUPPORT MUCH MORE THAN PC SKIES FOR AREAS SOUTHEAST OF
A KMLP TO KLWS LINE..AND EVEN THAT MAY BE A STRETCH AS BOTH THE
GFS AND NAM MAY BE TRYING TO PIVOT THE DEFORMATION AXIS/DEEPER
MOISTURE TOO FAR WEST.
ELSEWHERE...ACROSS THE VAST MAJORITY OF OUR CWA THE AIR MASS IS
BONE DRY EVIDENCED BY SURFACE DEW POINTS PREDOMINATELY IN THE
TEENS. MODEL CROSS SECTIONS INDICATE COLUMN RH/S IN THE 15 TO 25
PERCENT RANGE WITHIN THE NELY FLOW ALOFT. SO EXPECT WALL TO WALL
SUNSHINE FOR ALL BUT THE SOUTHEAST CORNER TODAY WITH TEMPERATURES
REMAINING 10 TO 15 DEGREES BELOW CLIMO. ABOUT THE ONLY LOCATIONS
THAT MIGHT EXPERIENCE SENSIBLE WARMING WILL BE ALONG THE EAST SLOPES
OF THE CASCADES AND OKANOGAN VALLEY. OTHERWISE...DESPITE SLIGHT
WARMING AT AND JUST BELOW 850 MB...MIXING WILL BE MUCH LESS
EFFICIENT THAN ON FRIDAY SO READINGS WILL END UP BEING VERY
SIMILAR MOST AREAS IF NOT A LITTLE COOLER ACROSS THE SOUTHEAST.
THE NELY SURFACE MSLP GRADIENT WILL CONTINUE TO RELAX THROUGH
TONIGHT...BUT IT WAS SUFFICIENT TO KEEP WINDS UP THIS PAST NIGHT
AND THAT KEPT TEMPS FROM BOTTOMING OUT MOST AREAS. CONSEQUENTLY...MIN
TEMPS TONIGHT OUGHT TO BE THE COLDEST OF THE PAST SEVERAL NIGHTS
WITH SUB-FREEZING TEMPS MORE WIDESPREAD GIVEN EXCELLENT
RADIATIONAL COOLING SET UP. /JONES
SUNDAY THROUGH FRIDAY...RIDGE MOVING IN FROM THE WEST PUSHES LARGE
LOW PRESSURE CIRCULATION TO THE EAST AND AWAY FROM THE FORECAST
AREA...KEEPING THE WRAP AROUND MOISTURE ON THE EAST SIDE OF THE
LARGE LOW FAR ENOUGH AWAY TO KEEP A RELATIVELY DRY FORECAST GOING
SUNDAY. RIDGE GETS A BIT OF A DIRTY LOOK TO IT MONDAY AS IT STARTS
TO FLATTEN OUT RATHER QUICKLY...SO MINOR POPS PRETTY MUCH REMAIN
LIMITED TO THE CASCADE CREST UNTIL MONDAY NIGHT/TUESDAY AND EVEN
THEN MOST OF THE ENERGY WITH PASSING WAVES LOOKS TO REMAIN FOCUSED
IN CANADA SO POPS ARE PRETTY MUCH CONFINED TO NORTHERN LOCATIONS.
WEDNESDAY THROUGH FRIDAY THE FLATTENED RIDGE DOESNT APPEAR IN THE
MODELS TO HAVE ANY SIGNIFICANT SHORTWAVE FEATURES OF INTEREST
MOVING THROUGH IT TO BUMP POPS BACK UP IN ANY FASHION...IN FACT
THE EARLIER FORECAST WAS BASED MORE OR LESS ON MEMBERS OF NUMEROUS
MODEL RUNS HINTING AT REAMPLIFICATION OF THE RIDGE OVER THE AREA
AS A TROF DIGS OFFSHORE IN THE THURSDAY AND FRIDAY TIME
PERIOD...WHICH IS PROBABLY BEST DEPICTED TO A DEGREE IN THE OLD
12Z ECMWF RUN FROM YESTERDAY. WITH THIS IN MIND THE MORE THAN
SUBTLE WARMING TREND TAKING PLACE AFTER WEDNESDAY AND ON INTO
FRIDAY REMAINS UNCHANGED. /PELATTI
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE FOR ALL TAF SITES THROUGH AT LEAST 12Z
SUNDAY. A COOL AND VERY DRY NORTHEAST FLOW ALOFT WILL CONTINUE TO
DOMINATE THE AREA THROUGH THE PERIOD. ASIDE FROM A FEW MID-LEVEL
CLOUDS SOUTHEAST OF KMLP-KLWS LINE...SKIES WILL REMAIN CLOUD FREE.
LOCALLY BREEZY CONDITIONS WILL REDEVELOP AFTER 15Z ESPECIALLY ACROSS
EASTERN SECTIONS OF THE COLUMBIA BASIN. /KJ
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 51 26 54 33 57 38 / 0 0 0 0 0 10
COEUR D`ALENE 50 24 53 32 58 38 / 0 0 0 0 0 10
PULLMAN 51 25 52 32 60 38 / 0 0 0 0 0 10
LEWISTON 56 30 57 35 65 40 / 0 0 0 0 0 0
COLVILLE 59 22 58 29 58 32 / 0 0 0 0 0 20
SANDPOINT 50 21 51 27 54 35 / 0 0 0 0 0 20
KELLOGG 47 25 52 31 55 36 / 0 0 0 0 0 20
MOSES LAKE 58 25 60 30 62 38 / 0 0 0 0 0 0
WENATCHEE 57 31 59 39 61 42 / 0 0 0 0 0 0
OMAK 58 21 58 31 60 36 / 0 0 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...FREEZE WARNING UNTIL 11 AM PDT SUNDAY FOR LEWISTON AREA.
WA...FREEZE WARNING UNTIL 11 AM PDT SUNDAY FOR LOWER GARFIELD AND
ASOTIN COUNTIES.
FREEZE WARNING UNTIL 11 AM PDT SUNDAY FOR MOSES LAKE AREA...
WENATCHEE AREA.
&&
$$
