A cool upper-level trough combined with a few hours of surface heating resulted in widely scattered convective showers during the afternoon hours of April 18th. One cell which tracked just north of Genesee produced a rope-like funnel cloud for several minutes and was captured on photograph.
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The episode as NWS OTX wrote it up.
A cool upper-level trough combined with a few hours of surface heating resulted in widely scattered convective showers during the afternoon hours of April 18th. One cell which tracked just north of Genesee produced a rope-like funnel cloud for several minutes and was captured on photograph.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Spokane, WA wrote its last area forecast discussion before the first event at Apr 18, 3:36 PM PST, 29 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 436 PM PDT Wed Apr 18 2012 .SYNOPSIS... After another round of precipitation across the Inland Northwest tonight, a dry day is likely for the majority of the region on Thursday before the next moist frontal system arrives on Friday. Warmer than average temperatures are expected over the weekend. A return to more seasonal temperatures is expected as a cold front arrives Tuesday. && .DISCUSSION... Tonight and tomorrow...Pops remain in place for the early evening to accommodate ongoing convective showers, some of which have produced small pea size graupel. Pops show a decreasing trend overnight and into tomorrow as the trof of low pressure overhead moves east and out of the area and is replaced by shortwave ridging. Cloud cover and fog forecast will likely need some adjustments as abundant low level moisture leftover from these showers and the ridging moving in from the west will stabilize the atmosphere and allow for some development of late night and early morning low stratus and fog. /Pelatti Thursday night through Saturday...High pressure over the Pacific Northwest will quickly become zonal by Thursday as the upper level jet sags southward through British Columbia. This will result in a day of wet weather on Friday. High pressure will then build into the region on Saturday for a warming and drying trend to begin the weekend. As high pressure breaks down late Thursday a warm front with a significant Pacific moisture tap will move into the region from northwest to southeast overnight and into early Friday. A weak cold front will sag into the region from the north through the afternoon. The lift will be mainly provided by isentropic lift and orographics, although there are a few weak waves associated with the weak cold front to aid in forcing. However, PW's rise to over .90 of an inch of water, so this will be a nice moisture tap indeed. While lift and forcing are not very robust the shear amount of moisture will be enough for just about all locations to get wet. Southeast-south flow will put the focus of the heaviest precipitation along the Cascades and Okanogan Highlands then tracking across the northern mountains and into the Panhandle mountains through the day. Friday night and Saturday high pressure will build back into the region. Orographic showers will continue across the eastern highlands into the evening, otherwise dry across the forecast area through Saturday. Heights and 850mb temps will be on the rise with max temperatures rising into the mid to upper 60s across the northern zones and into the 70s across the southern zones. /Tobin Saturday night through Wednesday...a ridge of high pressure will bring mostly dry and very warm conditions to the Inland Northwest for Sunday. Southwest flow will bring some mid level moisture into the region by Sunday afternoon. Instability from daytime heating will act on this moisture to bring the threat of showers to the higher elevations. A few thunderstorms could be possible across the southeast portion of the forecast area. The ridge axis will be over Idaho Sunday and this is expected to be the warmest day. By Monday the ridge will be nudged east by an approaching Pacific trough. Moist southwest flow will continue to stream into the region with increasing chances of showers and afternoon thunderstorms on Monday. A cold front will push through the region Tuesday with much cooler temperatures on tap. Breezy conditions will accompany the frontal passage Monday night and Tuesday. Model guidance diverges by Tuesday night in the timing of the next shortwave trough so pops trend toward climo. Temperatures will remain on the cool side as models indicate either a trough or westerly flow over the region. /Kelch && .AVIATION... 00Z TAFs: Scattered showers and isolated thunderstorms will diminish after sunset. Low level moisture from convective showers will be trapped under weak high pressure moving in overnight. This will allow some minor stratus/fog formation, mainly affecting the eastern TAF sites with generally MVFR/locally IFR ceilings and visibilities through 16z Thursday. VFR conditions will prevail through 00z Friday with mid and high clouds moving in from the west ahead of the next round of precipitation expected late Thu. /EK && .PRELIMINARY POINT TEMPS/POPS... Spokane 36 55 45 63 42 67 / 50 10 60 50 10 10 Coeur d'Alene 36 55 43 61 41 66 / 50 10 70 60 20 10 Pullman 34 55 46 66 41 68 / 40 10 60 70 30 10 Lewiston 39 64 50 69 48 74 / 40 10 60 30 30 10 Colville 34 59 43 66 40 68 / 50 10 70 50 10 0 Sandpoint 35 56 41 59 40 63 / 60 10 80 70 20 10 Kellogg 34 53 41 57 41 64 / 70 10 70 70 50 20 Moses Lake 36 60 44 72 43 73 / 0 20 40 20 0 0 Wenatchee 39 61 48 67 45 72 / 10 20 40 20 0 0 Omak 34 60 40 70 40 71 / 10 10 50 20 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SPOKANE WA 557 AM PDT WED APR 18 2012 IDZ001>004-026-027-WAZ031>038-041>044-191300- NORTHERN PANHANDLE-COEUR D'ALENE AREA-IDAHO PALOUSE- CENTRAL PANHANDLE MOUNTAINS-LEWISTON AREA- LEWIS AND SOUTHERN NEZ PERCE COUNTIES-NORTHEAST BLUE MOUNTAINS- LOWER GARFIELD AND ASOTIN COUNTIES-WASHINGTON PALOUSE- MOSES LAKE AREA-UPPER COLUMBIA BASIN-SPOKANE AREA- NORTHEAST MOUNTAINS-OKANOGAN HIGHLANDS-WENATCHEE AREA- EAST SLOPES NORTHERN CASCADES-OKANOGAN VALLEY-WATERVILLE PLATEAU- 557 AM PDT WED APR 18 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH IDAHO... NORTH CENTRAL IDAHO...CENTRAL WASHINGTON...EAST CENTRAL WASHINGTON...NORTH CENTRAL WASHINGTON...NORTHEAST WASHINGTON AND SOUTHEAST WASHINGTON. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SPOKANE WA 429 PM PDT WED APR 18 2012 IDZ026-190130- LEWISTON AREA- INCLUDING THE CITIES OF...LEWISTON...LAPWAI...PECK...CULDESAC... GIFFORD 429 PM PDT WED APR 18 2012 AT 420 PM PDT LEWISTON AREA MEDIA RELAYED A REPORT OF A FUNNEL CLOUD THAT OCCURRED ON THE LEWISTON GRADE AT AROUND 4:10 PM PDT. THE FUNNEL DISSIPATED... BUT A THUNDERSTORM WITH HEAVY RAIN AND SMALL HAIL CONTINUED IN THE AREA. WIDESPREAD SHOWERS WITH EMBEDDED THUNDERSTORMS WILL CONTINUE OVER THE REGION THROUGH THE LATE AFTERNOON AND EARLY EVENING. BE PREPARED FOR HEAVY RAIN AND SMALL HAIL.
The Spokane radar (KOTX), 129 km away, was scanning. The volume nearest the first event began at 00:02 UTC.
1 funnel cloud. Local standard time, as filed.
The media relayed a report and pictures of a funnel cloud that was sighted on the Lewiston Grade, roughly five miles northwest of Genesee between 1605 and 1610 PDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
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