####018004314#### FXUS65 KGJT 242011 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 211 PM MDT Wed Apr 24 2024 .KEY MESSAGES... - Precipitation chances increase Thursday with widespread valley rain and mountain snow showers. Snow levels will be around 8-9 kft and accumulation on the roads will be most likely at night. - Cooler and unsettled conditions are expected continue through the weekend with an increasing probability of significant high elevation snow accumulations and travel impacts through early Monday. && .SHORT TERM /THROUGH THURSDAY NIGHT/... Issued at 159 PM MDT Wed Apr 24 2024 Southwest flow is beginning to ramp up across the region ahead of the next system, which is currently making landfall in California. Some moisture has pooled up in the northern third of forecast area, so surface heating has resulted in shower development. This convection is terrain-driven and may last through the evening. More wind than rain is possible in spots based on dry low levels. Perhaps gusts upwards of 40 mph could occur. Tonight that shortwave trough progresses eastward leaving us in warm southwest flow. Night time temperatures in these regimes typically end up warmer than guidance so tried to hold on to some persistence. By late tomorrow morning the trough starts to enter the western part of the CWA then move through the rest of the area in the afternoon. Large-scale dynamics and a cold front will provide plenty of lift for precipitation. Steep lapse rates look to support modest instability and a fairly uncapped environment. So expect widespread showers and even some thunderstorms through most of the afternoon. Snow levels initially start around 8-9 kft and the high late April sun angle should limit accumulation on the roadways during the day. The mositure associated with this system fills in over the northern Great Basin, so as the trough crosses the Divide flow becomes WNW which keeps that moisture advecting into our area. Showers and a few storms will linger as long as the moisture streams in through the overnight hours with maybe a overall decrease in coverage. By sunrise Friday morning some of the high mountain passes could be looking at a few inches of snow. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Issued at 159 PM MDT Wed Apr 24 2024 Friday will see the effects of additional cold air spilling into the Great Basin and Intermountain West beneath a broad area of cyclonic flow. A short ripple of ridging will quiet things a touch Friday, but moisture and orographics will keep showers in the forecast, especially by afternoon, when moisture supplies pick up for good into early Sunday morning. Afternoon highs on Friday will be nearly 20 degrees colder across the region following a hot and dry period this week. Mountain locales can expect accumulating snowfall, mostly above 9000 feet, where multi day snow totals for the entire weekend look like they could crest 6-12 inches, including some higher totals on the bigger peaks. High temperatures in the 40's will likely chew into much of the daytime accumulation, as well as impacts on local roadways. Unsettled weather quiets down late Sunday thanks to high pressure building in. Monday looks like a return to seasonal normals with respect to temperature, a short lived stop on the way back to hot and dry conditions that develop under the amplifying ridge. Early next week will look familiar to this past week, given model predictions work out. Spring hasn't given up on us yet, but each of these warm ups are squeezing the life out of it slowly. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1143 AM MDT Wed Apr 24 2024 VFR conditions will prevail at terminals this TAF period with gusty southwest winds this afternoon. A few scattered mid clouds will continue to form on the mountains today, with an isolated shower or gusty outflow possible under virga showers in northwest Colorado and northeast Utah. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...KJS LONG TERM...LTB AVIATION...TGJT ####018005077#### FXUS65 KPIH 242012 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 212 PM MDT Wed Apr 24 2024 .SHORT TERM...Today and Thursday. There continues to be an upper level low off the Central coast of California, which is bringing moisture and instability into our area in southwest flow aloft. Farther, north and west off the Pacific coast of Oregon there is a low system and associated moisture and frontal boundary. This afternoon into early evening, expect isolated showers and thunderstorms for our northern areas and scattered showers and thunderstorms (SB CAPE of 250 to 500 J/kg) for our southern areas, generally south of the Eastern Magic valley and Snake plain. With dry air in place especially at the surfaces (PWATs around 0.40-0.80), look for gusty outflows up to around 40 mph this afternoon into early evening with showers and thunderstorms. Also, expect small hail and brief moderate to heavy showers with any storms. Temperatures will be 8 to 12 degrees above normal today, the warmest temperatures for at least a week (next Wednesday). Look for isolated overall light convection this evening into tomorrow morning. Thursday the system off the Oregon Pacific coast starts to approach. This system will bring drier air and breezy winds out ahead of it. The moisture with this system isn't expected until late Thursday into Friday. Thursday, especially in the afternoon, due to residual moisture and instability from today, look for isolated to scattered showers and thunderstorms mainly along the Eastern Highlands from the Snake plain to the Wyoming border. Look for breezy afternoon conditions (wind gusts of 20 to 35 mph) for our western areas, especially the Eastern Magic valley. Not much, if any, precipitation is expected in the Eastern Magic valley Thursday. Only a very isolated chance of precipitation is expected in our western mountains Thursday. Temperatures will be cooler Thursday than today, just a few degrees above normal. Wyatt .LONG TERM...Friday through next Wednesday. Precipitation chances will become increasingly widespread and increase on Friday as the trough axis shifts overhead. Daytime temps will decrease by another 5 to 10 degrees on Friday following a cold front passage. After that, temperatures look to remain fairly stable for Saturday before they begin to trend slightly warmer again. While 500 mb ensemble clusters still feature differences regarding the timing and depth of the next low working into the PNW and a ridge building in from the west/southwest, the majority of the solutions feature some degree of more westerly/zonal flow over Idaho early next week as these two upper level features struggle to take control. Models do show southwest 700 mb winds increasing to around 30 mph which will support breezy conditions at the surface. Depending on which feature dominates the pattern over Idaho will directly impact forecast temperatures and precipitation early next week. Deterministic models do show light precipitation signatures filtering into Idaho under southwest flow aloft, with the deterministic NBM carrying widespread PoPs up to around 40% through this period along with fairly stable daytime highs early next week just above normal. Cropp && .AVIATION... VFR conditions forecast throughout the period, although any moderate rain or storm to directly impact a terminal could reduce conditions below VFR. Mid-level and high clouds will increase as moisture filters in from the southwest today. Hi-resolution models show a band of rain showers filling in from east to west across all terminals beginning around 18z. Isolated to scattered thunderstorms will favor the corridor from KBYI, KPIH, over to KDIJ with less chances of thunder further north. HREF thunderstorm probabilities increase later into the afternoon to as high as 50% to 60% near the aforementioned terminals. Winds will remain light to breezy outside of any gusts associated with thunderstorms or outflows, which could reach as high as 40 kts. Cropp && .HYDROLOGY... No changes in the hydro forecasts at this time. Water levels on the Portneuf river continue to run high, just below moderate flood stage for the Portneuf river in Pocatello. The river forecast for the Portneuf river in Pocatello shows the river running above flood stage for the foreseeable future and likely climbing back to moderate flood stage by Thursday and peaking Sunday at around 10.5 feet or midway through moderate flood stage. At Topaz on the Portneuf, current levels are slightly above minor flood stage. Water levels are forecast to slowly rise toward the end of the week with warming temperatures through Wednesday and the return of precipitation chances in the second half of the week into the weekend. Wyatt && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$ ####018005767#### FXUS64 KBMX 242012 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 312 PM CDT Wed Apr 24 2024 ...New LONG TERM... .SHORT TERM... (This afternoon through Thursday) Issued at 1236 PM CDT WED APR 24 2024 A weak surface front has entered into northwest Alabama as we approach midday. Broken mid-level clouds between 7,000 and 10,000 feet associated with the front are currently present generally along and north of the I-85 corridor. The presence of the clouds are expected to temper the diurnal curve just a bit and lead to high temperatures in the mid to upper 70s, while full sunshine will send highs into the lower 80s for locations such as Troy and Eufaula this afternoon. In terms of the rain chances today, it appears that the high-res guidance from yesterday was a little too bullish in terms of the rain chances. The 12z KBMX sounding still contains an ample amount of dry air across the profile, which will continue to be a limiting factor in terms of convective development. I've continued the slight chance of showers and perhaps a storm across western counties in Central Alabama through the peak heating of the day as the surface front moves southward near the U.S. 80/I-85 corridor. Overnight tonight, mid-level clouds are expected to gradually clear in most locations. With the stalled surface boundary still in the vicinity, we could be looking at the chance for fog development as low-level moisture pools near and just south of the front. Patchy fog has been added to the forecast overnight for eastern and southeastern locations and nearby major lakes and stream basins. Temperatures will be allowed to drop into the upper 40s for northern counties north of the front, while upper 50s are expected in the far south. Upper level heights will begin to rise during the day on Thursday as a 500mb ridge develops over the southwestern Gulf of Mexico. A shortwave trough embedded within northwesterly flow aloft will move through the region, along with the surface front lifting northward as a warm front. At least isolated showers and storms will be possible during the peak heating of the day with warm temperatures expected in the low to mid 80s. 56/GDG && .LONG TERM... (Thursday night through next Tuesday) Issued at 311 PM CDT WED APR 24 2024 Continued the thinking of the previous forecast regarding potential for some coverage of showers/storms Thursday night mainly north of I- 20. Went above consensus for PoPs in that timeframe. Otherwise, highs in the 80s and lows in the upper 50s to low 60s will stay in place for several days. The thinking for Monday night remains largely the same with rain and possible thunderstorms chances mainly north of I-59/20. 12 Previous long-term discussion: (Thursday night through next Tuesday) Issued at 335 AM CDT WED APR 24 2024 An upper-level trough moving into the Southern Plains will induce southerly low-level flow as far east as Alabama on Thursday evening. A warm front extending from Northeast Oklahoma to West Alabama will accelerate northward with the onset of southerly flow. Beneath west- northwest 500 mb flow of 30-35 kts, increasing moisture and warm advection may trigger isolated or scattered showers and thunderstorms Thursday evening mainly north of I-20. Any such activity will shift to the northeast and out of our forecast area during the overnight hours. Two shortwave ejections will occur across the Plains and Midwest in the Friday through Sunday period while a ridge remains in control over the Southeast CONUS. Eventually the second trough in the Plains should progress eastward on Monday and Tuesday leading to increasing rain chances mainly north of I-59. 87/Grantham && .AVIATION... (18Z TAFS) Issued at 1236 PM CDT WED APR 24 2024 VFR conditions can be expected through the forecast period. Mid- level broken clouds will persist through the afternoon hours before decreasing in coverage overnight. An outside chance of isolated SHRA/TSRA remain in the forecast, but confidence is too low to even include a PROB30 at this time. Light westerly winds will continue this afternoon then become mainly calm overnight. We'll be watching for the potential of fog development across eastern and southeastern Alabama overnight tonight. Currently, no visibility restrictions have been included within the TAFs just yet, but based on model guidance trends and satellite/observation trends that could change in future TAF issuances. VFR conditions will continue through the day on Thursday. 56/GDG && .FIRE WEATHER... A weak front with just a few showers/storms moves through this evening. 20 ft winds will be westerly at 6 to 8 mph, with minimum RH values above 40 percent. Another chance of showers/storms exists Thursday afternoon, with an increase in coverage compared to Wednesday. 20 ft winds on Thursday will become easterly at 6 to 8 mph, with minimum RH values 30 to 35 in the northeast, and 35-45 percent, elsewhere. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 48 80 57 83 / 0 10 30 10 Anniston 51 80 58 82 / 10 10 30 10 Birmingham 54 81 61 83 / 10 20 20 10 Tuscaloosa 56 81 61 84 / 20 20 10 0 Calera 55 80 61 82 / 20 20 10 0 Auburn 57 80 62 82 / 10 20 10 10 Montgomery 58 84 62 86 / 0 20 10 0 Troy 57 83 60 85 / 0 20 0 0 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...56 LONG TERM....12 AVIATION...56