<message to="mfannin2@nwws-oi.weather.gov/jaxl#902f419e98f785837567c46bca973065" type="groupchat" from="nwws@conference.nwws-oi.weather.gov/nwws-oi"><body>KRIW issues Area Forecast Discussion (AFD) valid 2024-06-01T04:14:00Z</body><html xmlns="http://jabber.org/protocol/xhtml-im"><body xmlns="http://www.w3.org/1999/xhtml">KRIW issues Area Forecast Discussion (AFD) valid 2024-06-01T04:14:00Z</body></html><x xmlns="nwws-oi" id="nwws_processor.6825" issue="2024-06-01T04:14:00Z" ttaaii="FXUS65" cccc="KRIW" awipsid="AFDRIW"><![CDATA[

568

FXUS65 KRIW 010414

AFDRIW



Area Forecast Discussion

National Weather Service Riverton WY

1014 PM MDT Fri May 31 2024



.KEY MESSAGES...



- Active mountain snowmelt will occur Saturday through Monday as

  daytime high temperatures climb to 5-10F above normal.

  Foothill creeks and streams see daily diurnal rises.



- Above normal temperatures combined with a breezy west to

  southwest wind could elevate rangeland fire conditions over 

  central and southern Wyoming Monday.



- Temperatures across the region will be above normal the latter half

  of next week as a ridge of high pressure builds across the 

  western United States.



&&



.DISCUSSION...

Issued at 1250 PM MDT Fri May 31 2024



Cloud cover dissipated across the far north and eastern zones late 

Friday morning as cyclonic flow exited to our northeast. This 

has left abundant sunshine and seasonal temperatures across the 

forecast area early Friday afternoon. These conditions persist 

through Saturday morning with little more than increasing high 

clouds. Saturday finds mid-level moisture progressing into 

southwest Wyoming from the Great Basin in zonal flow. Daytime 

heating leads to isolated convection over the southwest mid to 

late afternoon and after 5 PM for portions of central Wyoming. 

Instability is limited and the sub-cloud layer is dry, so gusty 

outflow wind around 40kts would be the primary convective 

hazard. It appears this mid-level plume continues to traverse 

southwest and central Wyoming through Saturday evening and into

the Sunday morning hours, so light showers may indeed linger 

much of the night. Otherwise, cloud cover steadily increases 

Saturday night helping to keep temperatures warm for Sunday 

morning. Shortwave energy swings east-southeast across the 

forecast area around midday Sunday. Showers look to be a decent 

bet (30-50 percent) across the northwest and most areas east of

the Continental Divide, but extensive cloud cover Sunday 

morning should hinder instability for stronger convection that 

afternoon and evening. 



A trough off the Pacific Northwest coast spins a stronger 

shortwave toward western Wyoming Monday afternoon. Instability 

is more favorable for deeper convection across the west and 

north Monday afternoon and early evening. Breezy southwest wind 

Monday helps to boost temperatures a few degrees from those of 

Sunday, while also lowering relative humidity. As such, elevated

rangeland fire weather conditions are possible across portions 

of central and southwest Wyoming Monday afternoon. The warmer 

temperatures of the Saturday through Monday time period enables 

active mountain snowmelt, with the bulk of the remaining

snowpack positioned above 9K feet. Foothill creeks and streams 

will see daily diurnal rises, but available channel capacity and

the fact this will be higher elevation melt should limit 

flooding concerns. The exceptions would be the Salt and Snake 

drainages where lower snow has yet to melt, and those drainages 

fed by the northern Bighorn Mountains.



West-northwest flow follows for Tuesday dropping temperatures to 

more seasonal readings, while keeping isolated convection 

mainly confined to northern Wyoming and the I-25 Corridor. 

Ensembles continue to show a building ridge over the western 

United States for the latter half of next week. Temperatures 

rise into the 80s for many locations under the building ridge, 

approximately 10F above normal. There is some hint that a weak 

low in the Desert Southwest could circulate moisture north on 

the backside of the ridge late in the week. Thus, it is 

conceivable that isolated convection could still be present 

Thursday and Friday even with the ridge in place.



&&



.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...

Issued at 1007 PM MDT Fri May 31 2024



Light winds and clear skies will prevail overnight. On 

Saturday, mid level clouds will spread across the southern half 

of the state after sunrise, including for sites such as KRKS, 

KPNA, and KBPI. During the afternoon, isolated showers and weak 

thunderstorms are possible (20 to 30% chance) in the Upper Green

River Basin into Natrona County, and the main concern with 

these would be brief, erratic wind gusts to around 40 kt. The 

threat of this shower activity ends around sunset, with a 

return of light and variable winds for Saturday night.





&&



.RIW WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



DISCUSSION...Jones

AVIATION...VandenBoogart

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