Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
157 FXUS65 KCYS 071751 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1151 AM MDT Fri Jun 7 2024 .KEY MESSAGES... - Warm weather will continue through late week, with widespread highs in the 80s and lower 90s Friday. - Threat for strong downburst winds this afternoon and evening from high based thunderstorm development. - Monday and Tuesday will see the greatest coverage of late day showers and thunderstorms, while Wednesday and Thursday will be warmer with a general decrease in shower and thunderstorm coverage. && .SHORT TERM /THROUGH SUNDAY/... Issued at 235 AM MDT Fri Jun 7 2024 Low pressure analyzed over northern Carbon County this morning. Stationary front extends from this low eastward to near Torrington and then into southern Nebraska. South of this front...dewpoints are being observed in the 50s across northeast Colorado into southern Nebraska. Upper shortwave currently located in northwestern Wyoming. Front surges eastward after 18Z today with the surface low located near Chadron. Initial thunderstorms will be high based with GFS soundings showing inverted V soundings and DCAPE near 1000-1200 J/KG. Day crew will need to watch for severe down drafts from these high based storms. Mesoscale simulated radar shows a line of thunderstorms possibly developing across Carbon County after 00Z that eventually move into northern Platte and Goshen Counties before decreasing overnight. After a brief lull in convection...showers and thunderstorms redevelop late Saturday morning into the afternoon as PWATs increase up near 1 inch. ECMWF/GFS/NAM and SREF all painting widespread QPF across southern Wyoming and the southern Panhandle Saturday afternoon. Afternoon instability up near 1200 to 1500 J/KG for the southeast WYoming plains into the Panhandle Saturday afternoon. A Marginal Risk for severe thunderstorms has been highlighted for parts of the CWA. For Sunday...a stronger cold front surges south across our entire northern and eastern CWA as a stronger upper shortwave tracks into South Dakota. 700mb temperatures fall considerably into the single digits with below zero temperatures to near the South Dakota/Nebraska Panhandle state line. Much cooler Sunday which will limit thunderstorm activity. Would envision low stratus and fog across the Panhandle to the east slopes of the Laramie Range with this scenario. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Issued at 235 AM MDT Fri Jun 7 2024 Sunday night/Monday...As daytime heating wanes, isolated to widely scattered showers and thunderstorms will end from west to east overnight Sunday night. West northwest flow aloft develops on Monday, and with plenty of low and mid level moisture available, scattered late day showers and thunderstorms will be on tap again. Temperatures slightly warmer than Sunday with less cloud coverage. Tuesday...Northwest flow aloft remains, though with increasing heights aloft along with warmer temperatures, and a decrease in low and mid level moisture, we should see less coverage of late day showers and thunderstorms. Slightly warmer with more sunshine expected. Wednesday...Even warmer as the flow aloft turns westerly, and with 700 mb temperatures near 15 Celsius, maximum temperatures will be in the mid 80s to lower 90s. Warmer temperatures aloft will increase the convective inhibition, and with less low and mid level moisture around, only a few late day showers and thunderstorms are expected mainly near the mountains. Thursday...Similar synoptic pattern as on Wednesday, though low level winds will become upslope northeast, and with an increase in low and mid level moisture, we expect to see isolated to widely scattered late day showers and thunderstorms. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1138 AM MDT Fri Jun 7 2024 More active weather is expected this afternoon across the area. Showers and thunderstorms are expected to develop by mid afternoon and move from west to east across the area. These storms may produce erratic winds with gusts of 50 knots possible if they pass over or near a terminal. Used TEMPO groups to capture the most likely impact timing period, but there is some uncertainty in exact timing. Terminals along I-80 are the most likely to see an impact from lightning and wind this afternoon, but this can`t be ruled out at other terminals as well. Shower coverage will decrease after 03z or so, but scattered showers with a few rumbles of thunder will remain possible through the night, especially in Wyoming. A frontal boundary will swing through the area early Saturday morning, and this may bring areas of low clouds into the NE panhandle. Highest confidence MVFR is at KCDR and KAIA, but this could extend to KBFF and KSNY as well. && .HYDROLOGY... Issued at 400 PM MDT Thu Jun 6 2024 Several days of above normal temperatures have accelerated snowmelt runoff in the North Platte and Laramie River basins. Temperatures for the next several days are forecast to remain high enough to sustain rapid snowmelt and the subsequent high flows including minor flooding through Saturday. Snowmelt from the Sierra Madre and Snowy Ranges has driven the Encampment and North Platte Rivers to bankfull stages. The Encampment River is forecast to crest above flood stage on Saturday morning. Emergency management has reported minor flooding along the Little Laramie River. This flooding is expected to continue through the weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Flood Watch until 7 PM MDT this evening for WYZ113. NE...None. && $$ SHORT TERM...GCC LONG TERM...RUBIN AVIATION...MN HYDROLOGY...WFOCYS