Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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
533 FXUS65 KGJT 222324 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 524 PM MDT Wed May 22 2024 .KEY MESSAGES... - Showers and thunderstorms return Thursday, along with windier conditions along a slow moving frontal boundary. - Partly to mostly cloudy conditions continue Friday and into the weekend with the chance for afternoon showers and thunderstorms in the mountains. && .SHORT TERM /THROUGH THURSDAY NIGHT/... Issued at 136 PM MDT Wed May 22 2024 GOES-East satellite imagery shows some mid and high level clouds pushing into the region from the northwest this afternoon. This is out ahead of an approaching and deepening mid-level trough over the Intermountain West. Southwest flow well in advance of the trough is helping to boost afternoon temperatures roughly 10 degrees warmer than yesterday, and much closer to climatological normals. Dry and mild weather continues tonight, with overnight lows following similar warming trends. Accompanying the trough is a strong cold front which is progged to reach northeast Utah by daybreak Thursday morning. Though moisture is modest at best, a few showers are possible across the eastern Uinta mountains within the first couple of hours after sunrise. After that, the cold front is progged to gradually push through the CWA over the course of the day on Thursday. Given the aforementioned limited moisture, shower activity is expected to be mostly confined to the higher elevations in northwest Colorado and along the Continental Divide. More notable will be the winds ahead of, and along the cold front, which will likely gust upwards of 30 to 40 mph at times, especially during the afternoon. These winds gusts could even be enhanced further by any virga or dissipating showers. High temperatures will largely be similar to today, with the exception of northeast Utah and northwest Colorado where the cold front moves through earliest. Thus, highs there will be about 5 to 10 degrees cooler. The trough and cold front will exit the region to the east Thursday night, leaving clearing skies and light winds in their wakes. A cooler air mass overhead and near ideal radiational cooling conditions will lead to a chillier night, especially for the higher valleys and across the northern tier where temperatures may near or even dip below freezing. Otherwise, dry and quiet weather prevails into the morning hours on Friday. On a more personal note, today is my last day working at WFO Grand Junction as I`m moving on to new adventures within the National Weather Service. It`s been a pleasure serving eastern Utah and western Colorado for the past 4 years, and I`m honored and proud to have been given the opportunity to live, work, and play on the Western Slope. Until next time! && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 136 PM MDT Wed May 22 2024 The forecast area will see a bit of a lull in shower activity on Friday as the last system pushes farther east and ahead of the next system upstream to the west. That said, enough moisture remains to fuel isolated showers/thunderstorms along the central and northern Colorado portion of the Continental Divide as the atmosphere becomes conditionally unstable with surface warming and jet divergence providing the necessary support. Chances increase Friday night and peak Saturday afternoon as the trough to the west moves from the Great Basin and over the forecast during this period. However, there`s a concerning spread in timing between the ECMWF and the GFS solutions with the former describing the timing just described. The latest GFS was markedly slower. It should be noted that due to office operations, this discussion was prepared in the morning before the 12Z/ECMWF was available so differences may be overstated. That said, the forecast for Saturday night and Sunday could be in flux depending ECMWF adjustments, or lack thereof. The slower GFS showed a short wave trough trailing the main trough which is indicated to continue to generate scattered showers for the northern and central Colorado mountains and the northwest Colorado Plateau. The ECMWF keeps that energy well north of the area and as a result, limited showers to Saturday evening with little chance for additional precipitation beyond the early morning hours Sunday. However, despite their differences, models were in agreement with a shallow long wave ridge forming over the Rockies early next week. Drying under the ridge will end shower/storm potential for all but mountains forming the Continental Divide. Given continued showery conditions and in the absence of warm air advection, temperatures are expected to hover around 5 degrees below normal through the weekend, but a warming trend arrives Monday and by Tuesday highs will range from 5 to 10 degrees above normal. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 522 PM MDT Wed May 22 2024 The main concern over the next 24 hours will mainly be wind related. Stronger winds aloft will create areas of LLWS overnight which will eventually mix down to the surface as gusts of 25 to 40 mph through tomorrow evening. Outflow winds near showers across northwest Colorado could also produce some stronger gusts. Otherwise VFR should prevail with low probability of ILS at KHDN tomorrow afternoon near showers. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...MDM LONG TERM...NL AVIATION...TGJT