609  
FXUS66 KOTX 221805  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
1105 AM PDT MON JUL 22 2019  
   
SYNOPSIS
 
 
MUCH WARMER WEATHER WILL ARRIVE TODAY AND TUESDAY WITH  
WIDESPREAD HIGHS IN THE UPPER 80S AND 90S. THE POSSIBILITY OF  
HIGH BASED THUNDERSTORMS WILL ALSO DEVELOP DURING THIS HOT PERIOD  
ESPECIALLY TUESDAY NIGHT. A COLD FRONT PASSAGE WILL MODERATE  
TEMPERATURES BACK TO NEAR NORMAL WEDNESDAY, BUT WILL BRING WITH  
IT BREEZY WINDS. DRY AND SEASONABLY WARM CONDITIONS ARE EXPECTED  
FOR THE END OF THE WORK WEEK.  
 

 
   
DISCUSSION
 
 
TODAY: VERY TRICKY AND DIFFICULT FORECAST FOR THE NEXT 36 HOURS.  
SOME ELEVATED SHOWERS HAVE BEEN MOVING UP OVERNIGHT FROM EASTERN  
OREGON. THEY ARE ALREADY INTO THE LC VALLEY AND CAMAS PRAIRIE.  
HAVE NOT BEEN ABLE FIND ANY PRECIP REACHING THE GROUND YET IN OUR  
FORECAST AREA. LIGHTNING HAS WANED OVERNIGHT, BUT THE NAM IS  
SHOWING AFT 5AM SOME STRONGER ELEVATED CAPE MOVING INTO THE  
AFOREMENTIONED AREA. SO HAVE KEPT OUR THREAT OF THUNDER THROUGH  
THE MORNING HOURS. THEN IN THE AFTERNOON THE CHANCE OF SHOWERS AND  
THUNDERSTORMS EXPANDS ACROSS MUCH OF EASTERN WA AND N ID, AS WELL  
AS ALONG THE CANADIAN BORDER OF THE NORTHERN CASCADES AND  
OKANOGAN VALLEY. WE ARE EXPECTING SOME MODERATELY DENSE MID AND  
HIGH LEVEL CLOUDS THIS MORNING INTO THE EARLY AFTERNOON. THIS  
COULD HAMPER OUR DAYTIME HIGHS. THE MODELS SEEM TO THINK THE  
THICKER CLOUDS WILL MOVE OUT OF THE AREA BY MID TO LATE AFTERNOON  
AND WE WILL STILL SEE HIGH TEMPERATURES PROBABLY REACHED EARLY  
THIS EVENING.  
 
TONIGHT AND TUESDAY: THE THREAT OF THUNDERSTORMS WILL CONTINUE  
THROUGH THE EVENING AND OVERNIGHT HOURS...AND THROUGH TUESDAY.  
ONCE AGAIN, ELEVATED INSTABILITY WILL BE MOVING IN AND STRETCH  
FROM THE BLUES INTO THE NORTH ID PANHANDLE. THEN ON TUESDAY THE  
THREAT EXPANDS IN THE AFTERNOON INTO PORTIONS OF THE CASCADES AND  
OKANOGAN VALLEY. THE MODELS HAD BEEN HINTING AT CONVECTION IN THE  
CASCADES YESTERDAY AND TODAY THE CONFIDENCE CONTINUES TO GROW AND  
EXPAND ACROSS THE AREA. TEMPERATURES WILL BE JUST A FEW DEGREES  
WARMER, FOR POTENTIALLY THE WARMEST DAY WE HAVE SEEN THIS SUMMER  
FOR MANY LOCATIONS. /NISBET  
 
TUESDAY NIGHT AND WEDNESDAY: EVERYTHING COMES TOGETHER FOR AN ACTIVE WEATHER  
EVENT ON TUESDAY NIGHT. THE HOT TEMPERATURES IN THE 90S, COMBINED WITH DEW  
POINTS IN THE LOWER 50S, CREATE A RATHER UNSTABLE ATMOSPHERE ON TUESDAY  
AFTERNOON. MEANWHILE A VERY STRONG NEGATIVE-TILT SHORT WAVE MOVES ONSHORE. THIS  
IS AN EXCELLENT PATTERN FOR SEVERE WEATHER IN OUR AREA. HOWEVER, THE TIMING IS  
NOT GOOD FOR SEVERE STORMS. THE SHORT WAVE MOVES THROUGH OUR AREA OVERNIGHT,  
RATHER THAN DURING THE AFTERNOON. THIS LATER ARRIVAL TIME ALLOWS THE LOWER  
ATMOSPHERE TO DECOUPLE, DECREASING THE INSTABILITY.  
 
EVEN SO, THERE IS STILL A LARGE AMOUNT (500-1000 J/KG) OF ELEVATED CAPE, ALONG  
WITH ABOUT 1 INCH OF PRECIPITABLE WATER. SO AS THIS SHORT WAVE SWINGS THROUGH  
IN THE EVENING, THUNDERSTORMS ARE EXPECTED TO DEVELOP AROUND 5PM ALONG THE  
WA/OR BORDER, SPREADING INTO THE UPPER COLUMBIA BASIN BY 8PM, AND THEN COVERING  
MOST OF EASTERN WA AND THE IDAHO PANHANDLE BY MIDNIGHT. THE MAIN THREAT WILL BE  
STRONG WIND GUSTS (FROM THE THUNDERSTORMS AND THE COLD FRONT) AND SMALL HAIL.  
EXPECT BRIEF DOWNPOURS, BUT THE STORMS WILL BE MOVING TOO FAST TO CAUSE ANY  
FLOODING CONCERNS. LIGHTNING COULD START SOME FIRES, AND THE GUSTY WINDS COULD  
HELP SPREAD FIRES. BUT THE RAIN AND HIGH HUMIDITY SHOULD LIMIT THE NUMBER OF  
FIRE STARTS AND SPREAD.  
 
THE SYSTEM EXITS THE REGION QUICKLY BY WEDNESDAY MORNING, WITH JUST A FEW  
MORNING SHOWERS OVER THE NORTHERN/EASTERN MOUNTAINS. TEMPERATURES WILL BE  
ABOUT 15 DEGREES COOLER ON WEDNESDAY. RJ  
 
WEDNESDAY NIGHT THROUGH SUNDAY...FROM MID WEEK ONWARD THERE IS  
LOOSE MODEL AGREEMENT FEATURING A COUPLE DAYS OF WARMING UNDER A  
FLAT RIDGE FOLLOWED BY A COLD FRONT PASSAGE ON OR ABOUT SATURDAY.  
 
FOR THURSDAY AND FRIDAY A SURFACE THERMAL TROUGH WILL RE-  
ESTABLISH ITSELF OVER THE COLUMBIA BASIN AS A SHORT WAVE RIDGE  
POPS UP OVER THE AREA. THIS WILL ALLOW TEMPERATURES TO RISE BACK  
INTO THE MID 80S ON THURSDAY AND PEAK IN THE UPPER 80S TO LOWER  
90S ON FRIDAY WITH LIGHT WINDS AND ABUNDANT SUNSHINE. THE EXPECTED  
ARRIVAL OF THE NEXT WEAK PACIFIC SHORT WAVE DISTURBANCE FRIDAY  
NIGHT OR SATURDAY DOES NOT APPEAR TO BRING ANY APPRECIABLE  
PRECIPITATION THREAT BUT MAY MANIFEST ITSELF AS A DRY AND BREEZY  
PERIOD ON SATURDAY WITH TEMPERATURES COOLING BACK INTO THE MID 80S  
OVER MOST LOCATIONS WITH THE REST OF THE UPCOMING WEEKEND  
REMAINING DRY AND BENIGN WITH SEASONABLY NORMAL TEMPERATURES.  
/FUGAZZI  
 

 
   
AVIATION
 
 
18Z TAFS: SHOWERS EMBEDDED IN THE MID-LEVEL MOISTURE PLUME CONTINUE  
TO MOVE NORTH AND NORTHEAST ACROSS EASTERN WA AND THE ID  
PANHANDLE. SOME HIGH-BASED THUNDERSTORMS ARE STILL EXPECTED TO  
DEVELOP AND MOVE NEAR MANY OF THE TAF LOCATIONS THIS AFTERNOON BUT  
IT REMAINS UNCERTAIN AS TO PROXIMITY AND TIMING. THEREFORE, A  
CLOSE WEATHER WATCH WILL BE MAINTAINED FOR THE TAF SITES IN THE  
REGION COVERED WITH A VCTS. THE TAFS WILL BE UPDATED AS  
THUNDERSTORMS MOVE NEARER TO THE AIRPORTS. THERE IS A CHANCE FOR  
SOME SHOWERS TO DEVELOP NEAR MWH-EAT DURING THE EARLY MORNING  
HOURS AFTER MIDNIGHT. OTHERWISE, VFR CONDITIONS WILL CONTINUE FOR  
ALL TAF LOCATIONS THROUGH THE FORECAST PERIOD. /AKY  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 90 61 93 58 78 52 / 10 10 10 50 0 0  
COEUR D'ALENE 89 60 93 58 76 52 / 20 10 20 60 10 0  
PULLMAN 90 58 92 55 75 49 / 30 20 20 60 0 0  
LEWISTON 97 68 99 65 84 58 / 20 20 10 50 0 0  
COLVILLE 91 53 97 53 83 45 / 20 0 0 50 20 0  
SANDPOINT 84 58 91 58 75 50 / 20 20 10 60 20 0  
KELLOGG 88 63 92 61 73 54 / 20 20 20 60 10 0  
MOSES LAKE 96 63 95 59 84 55 / 10 10 0 30 0 0  
WENATCHEE 93 67 92 62 81 58 / 0 10 10 10 0 0  
OMAK 93 63 95 61 83 56 / 10 0 10 50 10 0  
 

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

 
 

 
 
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