####018003331#### FXUS65 KFGZ 181657 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 957 AM MST Thu Apr 18 2024 .SYNOPSIS...Typical springtime weather with warm, dry, and breezy conditions persisting the rest of this week and through the weekend. && .UPDATE...Temperatures around 10 degrees above normal will continue across northern Arizona today. Southwesterly wind gusts up to 25 mph will be possible across the higher terrain near the AZ/UT border this afternoon. A weak trough off the California coast will continue to stream high clouds over northern Arizona through tonight. With a fairly benign pattern in place, no major updates were required to the ongoing forecast. && .PREV DISCUSSION /506 AM MST/...Mundane, uneventful weather is in store for northern Arizona. The Southwest U.S. remains under zonal flow, keeping breezy west to southwest winds and above average temperatures in the forecast the next several days. Most areas will experience afternoon high temperatures roughly 10 degrees above normal. A few ripples in the pattern will allow for an increase in cloud cover today and tomorrow, but overall, expect plenty of sunshine the next several days. Tuesday through Thursday...Slight changes will be felt next week as a shortwave trough is expected to push into the area around the Tuesday to Thursday time frame. There is a lot of disparity between the GFS and ECMWF when it comes to timing and positioning of the associated low pressure. Regardless, both models' ensembles agree on the very limited impacts of this system. It will lead to elevated winds, gusting at 25 to 35 mph in the afternoons out of the south-southwest. In addition, a mostly inconsequential cooling trend will bring temperatures towards seasonal conditions by midweek. While an increase in cloud cover is expected, precipitation seems unrealistic at this time as a moisture starved atmosphere helps prevent any chance of precipitation from entering the forecast. && .AVIATION...Thursday 18/12Z through Friday 19/12Z...Despite mid to high cloud cover increasing through the TAF period, VFR conditions will persist with ceilings generally above FL150. W-SW surface winds generally at 10-15 kts will have gusts near 20 kts after 17Z to 19Z, becoming light after sunset at around 02Z. OUTLOOK...Friday 19/12Z through Sunday 21/12Z...VFR continues under mostly clear skies. Breezy W-SW winds in the afternoons will become light overnight. && .FIRE WEATHER...Today through Friday...Dry and warm with west- southwest winds at 10-15 mph, gusting 20-25 mph both days. Afternoon relative humidity will be roughly 10-20% today, decreasing slightly Friday. Saturday through Monday...Dry, warm, breezy conditions remain. Modest westerly winds through the weekend will increase out of the west-southwest by Monday, gusting near 25-30 mph. Afternoon RH values will generally be between 10-20% each day with some valley locations dropping into single digits. && .FGZ WATCHES/WARNINGS/ADVISORIES...None. && $$ PUBLIC...TM/Mazon AVIATION...Mazon FIRE WEATHER...Mazon For Northern Arizona weather information visit weather.gov/flagstaff ####018005956#### FXUS65 KGJT 181658 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 1058 AM MDT Thu Apr 18 2024 .KEY MESSAGES... - Light snow will continue over the northern Colorado mountains with a couple inches at best expected above 10000 feet. - Unsettled weather continues through the end of the week as additional waves brush the region. - Temperatures will largely trend above normal through the week with winds gusting in the 20 to 30 mph range most afternoons. && .SHORT TERM /THROUGH FRIDAY/... Issued at 357 AM MDT Thu Apr 18 2024 Our forecast area is currently stuck between a northern stream and southern stream with the polar and subtropical jets. To our north, a large low pressure trough continues to gyre over the north-central CONUS and southern Canadian border, which is carving out a 110 kt polar jet. This jet is stretched across the Intermountain West through Wyoming and into the Dakotas and Minnesota. Moisture continues to stream in across the northern and central portions of the CWA with subtle shortwaves riding this boundary, generating some continued light scattered orographic showers mainly affecting the northern and central mountains. Much of the showers currently on radar seem to be having a tough time reaching the ground as the low levels remain dry. Expect this general pattern to continue through Friday and into the weekend. Snowfall amounts will be minuscule though with a couple inches at best in the northwest Colorado mountains with some higher peaks among the central Colorado mountains seeing a bit more but this will be above pass level with very limited impacts if at all. So, temperatures across the north will continue to be below normal due to the cooler air staying north of the boundary with more clouds and showers. To the south of this boundary, so really the central and southern parts of the CWA, it is a different story. Warm air advection continues as the southern sub-tropical jet tries to push in from the south with ridging trying to take place across Mexico into the Desert Southwest. So high temperatures will be holding steady through the end of the week at around 10 degrees above normal with no real change either way with this northern stream still in place. We will see periodic clouds and sun as mid and high level moisture traverses the area between the two streams. The gradient also remains tighter as a result, allowing for continued breezy conditions each afternoon with gusts in the 20s and 30s. Conditions look to remain dry in the lower elevations through this period with really the northwest Colorado mountains standing the best chance at any precipitation, although amounts remain on the lighter side. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 357 AM MDT Thu Apr 18 2024 Friday night sees the large Canadian low making its way into the Great Lakes, with the pressure gradient over eastern Utah and western Colorado relaxing a bit. At the same time a shortwave trough will be moving into the southern Great Basin. Dynamic lift and modest moisture associated with this wave will combine with favorable orographics to keep light showers going over mainly the northern and central Colorado mountains through the weekend. A transient ridge will bring a break Saturday evening before another weak wave embedded in the flow allows a few light showers to form over the higher terrain once again Sunday afternoon. With limited moisture and high snow levels, snow accumulations will be less than an inch up to 2 to 4 inches at the very highest elevations, above 11000 feet, through Monday morning. Generally zonal flow through the midweek point will continue to keep light orographic showers in the forecast each afternoon over the higher terrain. Ridging builds into the West Coast on Monday, with a tight gradient between it and the trough over the Northern Rockies leading to another afternoon of stronger, gusty winds across eastern Utah and western Colorado. This ridge builds in more firmly by Tuesday, with the gradient aloft relaxing, and sticks around through at least the midweek point. Models suggest a large Pacific low will approach the West Coast at this point, although they disagree substantially over almost every detail. This feature has potential to bring some precipitation to the Western Slope late next week. Temperatures will remain above normal, running around 10 degrees above normal through the weekend. As the aforementioned ridge builds in early next week, look for a gradual warming trend allowing daytime highs to climb to as much as 15 degrees above normal. That will put the desert valleys into the low 80s, the higher elevation valleys in the 70s, and the mountain towns in the upper 50s to low 60s. Under these warm, dry, and breezy conditions, caution should be used with any planned fires, as well as being mindful of other potential spark sources, despite fuels not yet being declared critical. Overnight lows will also run in that 10 to 15 degrees above normal range through the period. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1058 AM MDT Thu Apr 18 2024 No changes to the forecast with continued SCT to BKN clouds streaming overhead through much of the period. Scattered light snow showers will periodically impact the northern and central Colorado ranges with dry weather expected otherwise. Winds remain breezy with gusts of 20 to 30 kts expected this afternoon before speeds decrease overnight. VFR conditions prevail throughout the period. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...MDA LONG TERM...BGB AVIATION...TGJT ####018006540#### FXUS61 KCLE 181659 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1259 PM EDT Thu Apr 18 2024 .SYNOPSIS... High pressure today followed by a cold front late tonight into early Friday. High pressure returns with much cooler conditions into the weekend. && .NEAR TERM /THROUGH FRIDAY/... 12:30 PM Update... The clearing line has worked its way to the I-71 and I-77 corridors, so expect mostly sunny skies the rest of the afternoon along and west of there, with far NE Ohio and NW PA also expected to be mainly clear by 20Z. This will allow temperatures to rise into the low/mid 60s, except upper 50s may hold in far NE Ohio and NW PA. 9:30 AM Update... No changes this morning. The clearing line has reached NW Ohio with mostly sunny skies now occurring at Toledo and Findlay, and it will continue to work east the rest of the morning as low- levels gradually dry. This will allow all areas to see sunshine by early to mid afternoon. Temperatures are on track because the warming will accelerate as the sun breaks out. 6:55 AM Update... Some mid level cloud cover continues across Northern Ohio and Northwest Pennsylvania early this morning. Expect for this cloud cover to dissipate from west to east as the mid level ridging builds overhead. Original discussion... Brief mid level ridging builds over the region and lead to a period of quiet and dry weather through tonight. A cold front enters the region from the west late tonight and will introduce shower chances from west to east late tonight through late Friday morning. Dew points in the low 50's and a few hundred Joules of MUCAPE should be enough for a few embedded thunderstorms accompanying rain showers. Showers and storms will exit fairly quickly Friday morning and leave much of the area dry by Friday afternoon. One final day of near to above normal temperatures today before we undergo a pattern shift behind the cold front tonight. Highs in the mid 60s to 70 degrees this afternoon will be accompanied b overnight lows in the 50s. Slightly below normal on Friday with highs in the upper 50s the lower 60s. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... A ridge of high pressure accompanied by a generally dry airmass quickly builds in behind the front on Friday night. The upper level trough axis will slide east across the area on Saturday, pushing a stronger cold front across the area with a general broad cyclonic flow across the region. A partly to mostly cloudy cu deck will fill in with daytime heating on Saturday but most areas will be dry with only a shallow moist layer and dry air in the mid-levels aloft. There is sufficient lift focused into Pennsylvania to carry a 20 percent chance of showers but coverage of any rain showers will be limited. High temperatures on Saturday will likely occur by midday then fall through the afternoon as cold air advection strengthens. Westerly winds will be brisk in the 15-25 mph range with gusts as high as 30 mph making conditions feel somewhat brisk. Ridging at the surface builds in from the west on Saturday night with winds becoming light enough for areas of frost to develop. These will be inland from Lake Erie where low temperatures are forecast to drop into the lower 30s. Although it looks partly cloudy at this time, if skies clear out we may need frost advisories for favored areas. Sunday will be similar except with perhaps lighter winds so people should stay tuned to forecast updates and plan to shelter any tender vegetation if possible. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... A large area of surface high pressure will gradually build to the southeast through Monday with temperatures returning to near normal with lots of sun. Models indicate than an area of low pressure will slide east across northern Ohio or Lake Erie on Tuesday ahead of a piece of shortwave energy aloft. This will bring the next chance of showers and possibly thunderstorms. This will be a quick moving system with high pressure building south out of Canada behind it. This should push temperatures back to slightly below normal to end the period. && .AVIATION /12Z Thursday THROUGH Monday/... Mix of MVFR/VFR across the region with MVFR cigs around 2.5kft hanging around most terminals along and east of I-71 through this morning. As a ridge of high pressure builds overhead, anticipate for low/mid level clouds to clear out. High level clouds begin to enter the region from the west ahead of a cold front that will swing eastward late tonight through early Friday morning. Have showers entering western terminals around 07-09Z Friday morning and continuing to quickly progress eastward. For now, have introduced prevailing -SHRA with MVFR cigs at western and central terminals. It looks like we could tap into enough instability to get some embedded thunder, especially for western terminals, but not enough confidence to put thunder in the TAF with this issuance. Winds start the period westerly around 10 knots before turning southeasterly ahead of the cold front late this evening. Winds abruptly turn northwesterly behind the cold front early Friday morning while increasing to 10-15 knots with gusts to 20-25 knots possible. Outlook...Non-VFR possible Friday into Saturday in rain. && .MARINE... West to southwest winds of 10-15 knots will decrease through the day with lake breezes on the west half of the lake possible this afternoon as high pressure expands overhead. An area of low pressure will track northeast across Lake Erie on Friday pulling a cold front east across the lake behind it. Another trough will cross the Great Lakes on Saturday pulling a stronger cold front across the region. A Small Craft Advisory may be needed for areas east of Willowick with waves of 3 to 5 feet. A large area of high pressure will build east through the Ohio Valley Sunday through Monday. Another cold front will cross Lake Erie on Tuesday night with unsettled conditions returning. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...Iverson NEAR TERM...Garuckas/Iverson SHORT TERM...KEC LONG TERM...KEC AVIATION...Iverson MARINE...KEC