396
FXUS66 KOTX 070457
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
957 PM PDT TUE JUN 6 2023
SYNOPSIS
ABOVE AVERAGE SEASONAL TEMPERATURES WILL CLIMB INTO THE 90S
THROUGH MID WEEK WITH LITTLE RELIEF OVERNIGHT. CHANCES FOR SLOW
MOVING THUNDERSTORMS CAPABLE OF HEAVY RAIN AND GUSTY OUTFLOW WINDS
WILL INCREASE WEDNESDAY AND INTO NEXT WEEKEND. TEMPERATURES WILL
BE COOLER AND CLOSER TO SEASON AVERAGE FRIDAY INTO SATURDAY.
DISCUSSION
TUESDAY THROUGH THURSDAY: TODAY IS A PIVOTAL FORECAST DAY AS WE
TRANSITION FROM AN ANOMALOUSLY DRY PERIOD TO AN ANOMALOUSLY WET BY
LATER THIS WEEK. BREEZY NORTH WINDS (20-25 MPH) DOWN THE OKANOGAN
VALLEY UNDER THE RIDGE OF HIGH PRESSURE WILL BEGIN TO RELAX THIS
EVENING AS THE PRESSURE GRADIENT ALSO WEAKENS. THE EASTWARD PUSH OF
DRY AIR WILL SLOWLY ERODE OR MOISTEN UP WEDNESDAY FROM THE SOUTHEAST
AND CONTINUE THROUGH LATER THIS WEEK. THIS LAYOUT OF HIGH PRESSURE
TO THE NORTH AND TROUGHING SOUTH WITH A SOUTHEASTERLY ADVECTION OF
MOISTURE IS SIMILAR TO A MONSOON-TYPE PATTERN, WHICH I'VE SEEN
BEFORE, JUST NOT IN THIS PART OF THE COUNTRY.
TEMPERATURES WILL TOP OUT WEDNESDAY AND THURSDAY, DEPENDING ON
SPECIFIC LOCATION AND SHOULD BE THE WARMEST OF THE NEXT WEEK
AHEAD. WEDNESDAY AFTERNOON WE BEGIN TO GET A PUSH OF MOISTURE FROM
THE SOUTHEAST INTO CENTRAL IDAHO THANKS TO THE LOW OVER THE
SOUTHWEST. PRECIPITABLE WATER VALUES WILL CLIMBING TO 180-200% OF
NORMAL WEDNESDAY INTO THURSDAY. MID LAYER WIND FLOW WILL SHIFT
FROM SOUTH TO SOUTHEAST WITH SHEAR OF ABOUT 15 KNOTS. THE
INSTABILITY (CAPE) WILL BE QUITE HIGH (1000 J/KG OR SO) BUT THE
LOWER LAYERS WILL STILL BE MOISTENING UP. FORECAST SOUNDINGS ARE
INDICATIVE OF QUICK BUILDING (STEEPER LAPSE RATES) STORMS BUT WITH
A DRY SUBCLOUD AND BOUNDARY LAYER, GUSTY WINDS AND BRIEF RAIN MAY
BE THE BIGGEST THREATS WEDNESDAY AFTERNOON AND EVENING.
THURSDAY, WHILE STILL INCREASING THAT LOW-MID LEVEL MOISTURE WE'RE
NOW LOOKING AT 200-250% PWAT VALUES AND A MODEST BUMP IN
INSTABILITY (2000-2500 J/KG CAPE) OVER A WIDER AREA FROM THE IDAHO
PANHANDLE NORTHEAST THROUGH FERRY AND LINCOLN COUNTIES OF CENTRAL
WASHINGTON. THE STORM POTENTIAL WILL HAVE BETTER SHEAR AND
CONVECTIVE DEVELOPMENT AS WELL AS MOTION WHILE STILL INCORPORATING
THE HEAVY MOISTURE PROFILE. THE TEMPERATURES THURSDAY MAY BE
INHIBITED BY THE EXTENSIVE CLOUD COVER AND CONVECTION. THE INFLUX
OF MOISTURE WILL CONTINUE THROUGH THE EVENING THURSDAY LENDING TO
A MORE HUMID YET SLIGHTLY COOLER PERIOD OVERNIGHT INTO FRIDAY.
THE STORM PREDICTION CENTER HAS PLACED NORTHERN IDAHO AND EASTERN
WASHINGTON IN A MARGINAL OUTLOOK THURSDAY FOR SEVERE THUNDERSTORMS
(ABOUT 5% AT THIS TIME) AND LOCALLY WE ARE SEEING A 30-45%
PROBABILITY OF THUNDERSTORM COVERAGE OVER THE INLAND NORTHWEST. AS
MENTIONED, ALONG WITH THE THUNDERSTORM THREAT, COMES HEAVY RAIN.
WE ARE ALSO UNDER AN AREA OF MARGINAL TO SLIGHT RISK FOR EXCESSIVE
RAINFALL, MEANING THE POTENTIAL FOR HEAVY RAIN WILL EXIST FROM
THESE STORMS AS THEY TURN TO MORE SHOWERY RAIN. QUITE THE SETUP OF
HOT AND DRY TO STORMY AND WET, AS I SAID IT'S VERY SIMILAR TO A
DESERT SOUTHWEST MONSOON SETUP JUST 15 DEGREES FARTHER NORTH
LATITUDE. /DEWEY
FRIDAY THROUGH TUESDAY: FORECAST IS CHANGING A BIT FOR THE
EXTENDED PART OF THE FORECAST. FIRST, WE'LL START OFF WITH THE WET
WEATHER AT THE END OF THE WEEK. THE DETERMINISTICS AND ENSEMBLES
ARE NOW IN RATHER GOOD AGREEMENT ON THE UPCOMING WEATHER SYSTEM.
RATHER THAN A ROUND OF AFTERNOON/EVENING CONVECTIVE EVENT FOR
FRIDAY, THE MODELS ARE NOW SIDING WITH A SCENARIO WHERE THE
MOISTURE/PRECIPITATION THAT DEVELOPS IN THE SOUTHERN PANHANDLE ON
THURSDAY AFTERNOON WOULD SPREAD OVER THE REST OF THE AREA ON
THURSDAY NIGHT. THIS MAKES FOR A CLOUDIER, COOLER FRIDAY (HIGHS IN
THE 70S) WHICH IS NOT AS CONDUCIVE TO CONVECTIVE WEATHER. THERE
WILL STILL BE THUNDERSTORMS IN THE FORECAST, BUT THE 700-500MB
LAPSE RATES ON THURSDAY OF AROUND 7C/KM WILL BE REPLACE BY 5-6C/KM
ON FRIDAY. IT'S WORTH NOTING THAT THE ECMWF ENSEMBLE SHOWS
MINIMAL CHANCES OF EVEN 500 J/KG CAPE ON FRIDAY, WHILE THE
CANADIAN HAS 60-80% ODDS OF 1000 J/KG IN THE PANHANDLE, WITH THE
GFS SOMEWHERE IN BETWEEN. SO NOT A SLAM-DUNK FORECAST FOR STRONG
THUNDERSTORMS FOR FRIDAY.
PRECIPITABLE WATER WILL STILL BE OVER AN INCH, SO HEAVY RAIN IS
STILL A THREAT ON FRIDAY. THE EASTERLY FLOW AT 700MB ACTUALLY
FAVORS THE HEAVIEST RAIN POTENTIAL FOR CHELAN AND OKANOGAN
COUNTIES, WHICH ALSO HAVE SEVERAL BURN SCARS THAT WILL NEED
MONITORING.
FOR THE WEEKEND, THE LOW PRESSURE SYSTEM THAT WAS RESPONSIBLE FOR
ALL THIS MAYHEM LINGERS OVER OUR AREA WITH ALL OF ITS MOISTURE.
THE RESULT WILL BE SEASONABLY NORMAL TEMPERATURES (70S) WITH
AFTERNOON/EVENING SHOWERS AND STORMS. THIS ACTIVITY WILL BE FAIRLY
WIDESPREAD ON SATURDAY, BUT MAINLY OVER THE NORTHERN/EASTERN
SECTIONS ON SUNDAY THROUGH TUESDAY. TEMPERATURES WILL VERY SLOWLY
WARM FROM THE COOL FRIDAY, BUT NOT ALARMINGLY SO. AN OVERALL
PATTERN CHANGE SHOULD KEEP TEMPERATURES A LITTLE MORE MODERATE,
ALBEIT STILL ABOVE NORMAL. IN OTHER WORDS, THE HOT TEMPERATURES
OF TODAY AND TOMORROW WON'T LIKELY BE REPEATED ANYTIME BEFORE
FATHER'S DAY.
AVIATION
06Z TAFS: VFR CONDITIONS WILL CONTINUE TO PREVAIL THE NEXT 24
HOURS. INCREASING MID AND HIGH CLOUDS FROM CENTRAL IDAHO AND
SOUTHEAST WASHINGTON GOING INTO WEDNESDAY WILL KEEP CLOUD BASES
ABOVE 10K FEET.
PRELIMINARY POINT TEMPS/POPS
SPOKANE 58 91 63 88 63 76 / 0 0 10 40 60 80
COEUR D'ALENE 58 90 61 85 63 78 / 0 0 10 50 70 80
PULLMAN 57 87 61 83 59 74 / 0 10 10 50 60 70
LEWISTON 65 95 67 88 67 82 / 0 10 20 60 60 60
COLVILLE 51 91 57 88 59 77 / 0 0 0 40 60 80
SANDPOINT 57 89 61 84 62 77 / 0 0 10 50 60 80
KELLOGG 61 87 64 84 64 75 / 0 20 20 70 70 90
MOSES LAKE 54 95 61 90 62 76 / 0 0 0 20 50 50
WENATCHEE 63 94 68 92 66 74 / 0 0 0 10 30 50
OMAK 57 95 62 92 65 78 / 0 0 0 10 40 70
OTX WATCHES/WARNINGS/ADVISORIES
ID...NONE.
WA...NONE.
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