####018005127#### FXUS61 KCAR 041015 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 615 AM EDT Sat May 4 2024 .SYNOPSIS... High pressure will remain over the area today and tonight. An occluded front will approach on Sunday and cross the area Sunday night. High pressure will return Monday into Tuesday. Low pressure will approach on Wednesday. && .NEAR TERM /THROUGH TONIGHT/... 6:15 AM Update...The sky is mostly cloudy with just a few breaks of clearing. Sky cover looks good this hour. Adjusted temps up a couple degrees, mostly across central areas, where clouds have prevented cooling overnight. Previous discussion... We will remain in a narrow corridor of high pressure, both surface and aloft today, between a low well to our southeast and an occluded front approaching from the west. An initial band of moisture pushing out ahead of the front will slide into our region during the day today. However, moisture from this band will thin out as it pushes over the ridge and collapses under subsidence from the ridging. The effect for our weather will be clouds moving in today, then thinning for breaks of sunshine later this afternoon as upper level moisture dissipates. High pressure surface and aloft will be over the area tonight bringing a partly cloudy night. Some patchy low stratus may form again late tonight with some isolated areas of fog possible over the central or southern valleys. Otherwise, tonight will be dry and tranquil. && .SHORT TERM /SUNDAY THROUGH MONDAY/... Models are in pretty good agreement for this ptn of the fcst. Sun will begin ptly sunny, then become cldy and breezy in the Aftn as a s/wv an weakening warm occluded frontal zone begins to apch from the W. Shwrs and rn from this system will msly occur ovr the Rgn durg Sun Ngt with most areas receiving 0.10 to 0.20 inches, warranting max PoPs in the ovrngt hrs now in the categorical range. Most rn/shwr activity ovr our FA will move E of the FA by late Mon Morn. The tmg of a of a fairly strong secondary cold front and associated s/wv from Hudson Bay now appears to be after 00z Tue, likely to late for after diurnal max htg for any sig additional shwrs and isold tstms. The warmest air in the llvls will arrive durg by Mon Aftn allowing temps to get well into the 60s, perhaps even near 70 ovr inland low trrn lctns. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Any isold to wdly sct shwrs will move E of the FA behind a secondary cold front by late Mon Eve, with the rest of Mon Ngt and Tue looking to be fair, breezy and cooler, with some llvl cold advcn SC cld cvr likely ovr Nrn/Ern areas late Tue Morn into Aftn. Under Can sfc high pres, Tue Ngt looks to be fair with dmnshg winds and cool spcly Nrn areas with good radiational cooling. Wed will start ptly cldy ovr the Rgn, then turn msly cldy from the W as another weakening occluded sfc low and s/wv alf system apchs from the Midwest. Shwrs from this system are potentially could impact our FA Wed Ngt, but longer range models are not in good agreement on tmg or rnfl totals durg this tm frame, and on whether followup s/wvs will cont to bring additional shwrs from Thu Aftn thru Fri. The result is a long mention of chc shwrs into the late week with low confidence as to what day/ngt pd will actually receive appreciable rnfl. Subsequently max PoPs were kept in the high chc range. Longer range models are in a little more agreement on possible more sig rnfl toward the weekend, currently just beyond this fcst domain. Temps will be msly near to slightly abv normal for Wed thru Fri. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: MVFR ceilings this morning should improve to VFR by midday. VFR conditions are expected tonight, possibly lowering to MVFR again late tonight. Winds light east to northeast today becoming light southeast tonight. SHORT TO LONG TERM: Sun...all TAF sites VFR with mdt S winds. Sun Ngt...all TAF sites low MVFR of IFR clgs with Shwrs and rn. Mdt S winds. Mon...all TAF sites MVFR clgs becmg low VFR clgs by Aftn. Brief MVFR vsbys possible in shwrs. Lgt to mdt SW winds becmg W late in the day. Mon Ngt - Tue...all TAF sites VFR - low VFR clgs. Lgt to mdt NW winds. Tue Ngt - Wed...all TAF sites VFR, lowering low VFR clgs by late Wed Aftn with lgt shwrs. Lgt winds. && .MARINE... NEAR TERM: Winds will be light today. Seas will be around 1 to 2 ft today, dropping to around 1 ft tonight. SHORT TO LONG TERM: No hdlns anticipated at this tm ovr these ptns of the fcst. Kept close to blended wv model guidance for fcst wv hts with wvs msly composed of two spectral groups; a shorter 4 to 6 sec and a longer 10 to 12 sec pd swell. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Bloomer Short Term...VJN Long Term...VJN Aviation...Bloomer/VJN Marine...Bloomer/VJN ####018010353#### FXUS65 KSLC 041015 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 415 AM MDT Sat May 4 2024 .SYNOPSIS...Saturday will be warm with southerly winds increasing ahead of a storm arriving on Sunday. This storm will bring a cold front that will be precluded with strong wind gusts, particularly across western and southeastern Utah, on Sunday. Widespread valley rain and mountain snow will accompany the cold front with much colder temperatures. Conditions remain unsettled and cold through midweek. && .SHORT TERM (Through 12Z/6AM Monday)...Our next storm is moving onshore across northern California and the PNW in the form of a low pressure system that will begin to phase back into the mean flow and tilt negatively as it strengthens on its way to the Great Basin. This trough will bring strong southerly winds followed by colder temperatures and widespread valley rain and mountain snow, focused on northern Utah/SW Wyoming. Today, southerly flow and WAA will begin increasing ahead of this storm. This will result in temperatures in the mid 70s across most Utah valleys with mid 80s across lower Washington county and Lake Powell. 700 mb flow aloft increases to near 50 knots across Utah late Saturday and Sunday as this trough approaches from the west. These strong winds aloft will mix to the surface with advisory level magnitudes across western Utah beginning Saturday afternoon, and approaching warning level criteria for western Juab and Millard counties. These strong winds will be capable of producing reduced visibilities from blowing and drifting dust. As this trough moves further east winds will increase across southeastern Utah up through Castle Country on Sunday with widespread winds 35-45 mph gusting 60-65 mph Sunday afternoon. These winds will weaken as the direction shifts to the northwest behind a cold front that sweeps through the area from northwest to southeast during the day on Sunday. A 100+kt jet will help to direct an atmospheric river onshore the west coast with a generous portion of this moisture making it into our CWA. Ensemble mean PWATs on Sunday are forecast to be 0.66" for KSLC which would place this in the 90th+ percentile for this time of year. This moisture/jet will pair with a strong baroclinic zone, potentially undergoing frontogenesis, to produce widespread valley rain and heavy mountain snow along and behind it. Ahead of the front, atmospheric profiles are forecast to remain dry up to about ridgetop levels so only a few scattered showers and thunderstorms will accompany the pre-frontal environment. Peak precipitation rates across northern Utah will occur around midday Sunday as the cold front passes through. Temperatures will fall dramatically. H7 temperatures ~7C will quickly plummet to ~-7C in a matter of a few hours. Snow levels will also be falling to 5500-6000 feet by Sunday evening, and eventually to ~5000 feet by Monday morning which would result in precipitation transitioning to snow along the benches of northern Utah. A moist west/northwest flow will succeed the cold front. Steep lapse rates and lake induced instability will allow showers to continue to the east of the Great Salt Lake early Monday morning. .LONG TERM (After 12Z/6AM Monday)...High confidence exists for cool and unsettled conditions to persist through midweek across Utah and SW Wyoming. On Monday, northern Utah and SW Wyoming will reside beneath a region of moist cyclonic flow, and this will maintain persistent showers, particularly over high terrain areas of northern Utah as well as adjacent valleys. During the morning, snow levels will be quite low, on the order of 5000-5500 feet elevation, suggesting the atmosphere will be cold enough to support snow down to as low as benches. The ingredients will be in place to support lake effect snow (sufficient lake sfc to 700mb delta Ts, favorable fetch and sufficient moisture through the DGZ), and in fact local lake effect snow probabilities suggest a low to medium chance (30- 40%)for lake effect snow during the morning hours. The few available CAMs that extend out to 60hrs do indeed indicate localized heavier convective showers streaming off of the lake across the Northern Wasatch Front between Ogden and Bountiful. Majority of the model solution space suggests a slight reduction in shower activity Monday evening and early overnight Monday, although at least a few showers are likely to continue over the terrain of northern Utah owing to favorable upslope flow trajectories and sufficient moisture during this time. A trailing shortwave will act to enhance shower activity once again across northern Utah and SW Wyoming beginning early Tuesday morning, with showers persisting though much of the day. Tuesday morning appears to be another favorable period for lake effect, with locations from Bountiful to Salt Lake favored. Highest uncertainty both Monday and Tuesday mornings is whether temperatures will be cold enough to support snow in valleys with this activity, as the relatively warm lake may modify the boundary layer for those areas adjacent the downstream waters. We are confident that temperatures will be cold enough to support snow on benches, however with 1 to 2 inches of snow not out of the question. High enough precipitation rates could support snow down to valleys, or a combination of snow/graupel in convectively- driven showers. A high end scenario suggests up to 1" of snow in valleys for either period. Dry advection begins to take hold late Tuesday into Wednesday, reducing the coverage and intensity of shower activity. Should enough boundary layer moisture along with a sufficiently saturated DGZ (with respect to ice) we cannot rule out yet a 3rd consecutive morning with lake effect potential, this being Wednesday morning. Probabilities, while low, are non-zero in the 15- 25% range. With an increased northwest flow, this would favor areas from Bountiful to SLC. In the 48 hours from around sunrise Monday morning to around sunrise Wednesday morning, several additional inches of snow are likely across the northern mountains, with an additional 6 to 12 inches expected, per the most likely scenario, with locally higher amounts in the Ogden area mountains and Upper Cottonwoods, where favorable upslope and lake effect will act together to enhance amounts. 90th percentile amounts are as high as 16-24 inches. Temperatures of this magnitude for early May that support snow down to valley floors in the overnight and early morning hours are flirting with being outside of climatology for the time of year. Monday morning lows are expected to range from the upper 20s to low 30s across valley locations of southwest Utah and central Utah, with low to mid 30s across northern Utah thanks to clouds and precipitation. Slightly warmer temperatures are in store for Tuesday morning with even colder temperatures for Wednesday morning, with widespread upper 20s to low 30s lows currently forecast once again for southwest Utah, central Utah valleys and most valleys of northern Utah outside of Urban areas and away from the moderating effects of the Great Salt Lake and Utah Lake. Majority of the ensemble solution space suggests negative height and corresponding negative temperature anomalies will remain in place through Thursday across Utah and SW Wyoming, with about 1/3 of the distribution maintaining negative height anomalies by Friday. The magnitude of the anomalies will be diminishing, however, leading to a slow, gradual warming trend. After a cold Wednesday with temperatures 10F to 20F below seasonal normals, temperatures will rebound to within 10F of normal by Friday, with just over 3/4 of the model distribution suggesting temperatures will return to normal by Saturday. The remaining 1/4 of the solution space maintain a warming trend while keeping temperatures suppressed slightly below normal. Under this scenario, a slight chance of showers, especially over the terrain, persists into Saturday. Otherwise, a few showers will persist, largely coincident with daytime heating and over the terrain, through Thursday. && .AVIATION...KSLC...AVIATION...KSLC..VFR conditions will remain in place through the valid TAF period. Southerly winds are also forecast to be in place through the period as well, gradually increasing this afternoon and remaining southerly and gusty through Saturday night, with gusts in the 30 to 40kt range possible. There is a low, or 10 to 15 percent chance for nearby showers late this afternoon and early evening. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are expected across the area through the valid TAF period. Southerly winds will gradually increase this afternoon and remain southerly and gusty tonight. There is a low to medium (30-40 percent chance) for LLWS conditions to develop overhead steeper walled valleys overnight, as winds at the 2kft AGL level will increase into the 30-45kt range after 06Z tonight. Can't rule out isolated shower development over northern Utah terrain late this afternoon and early evening, otherwise widespread shower development will begin around the end of the period across northwest Utah. Patchy blowing dust may limit surface visibility over portions of SW Utah late this afternoon through tonight. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Wind Advisory from 3 PM this afternoon to noon MDT Sunday for UTZ101-122. Winter Storm Warning from 6 AM Sunday to noon MDT Tuesday for UTZ110>112. High Wind Warning from 3 PM this afternoon to noon MDT Sunday for UTZ115. High Wind Watch from Sunday morning through Sunday evening for UTZ120-121-128-130. WY...None. && $$ SHORT TERM...Mahan LONG TERM...A. DeSmet AVIATION...A. DeSmet For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity ####018000950#### FXIO20 RJTD 040600 RSMC GUIDANCE FOR FORECAST NAME HIDAYA INIT 040600UTC FORECAST BY GLOBAL MODEL TIME PSTN PRES MXWD T=000 06.3S 040.4E 1010HPA 22KT T=006 02.2S 038.7E 1006HPA 22KT T=012 01.5S 039.0E 1009HPA 18KT T=018 ///// ////// /////// ///// T=024 ///// ////// /////// ///// T=030 ///// ////// /////// ///// T=036 ///// ////// /////// ///// T=042 ///// ////// /////// ///// T=048 ///// ////// /////// ///// T=054 ///// ////// /////// ///// T=060 ///// ////// /////// ///// T=066 ///// ////// /////// ///// T=072 ///// ////// /////// ///// T=078 ///// ////// /////// ///// T=084 ///// ////// /////// ///// T=090 ///// ////// /////// ///// T=096 ///// ////// /////// ///// T=102 ///// ////// /////// ///// T=108 ///// ////// /////// ///// T=114 ///// ////// /////// ///// T=120 ///// ////// /////// ///// T=126 ///// ////// /////// ///// T=132 ///// ////// /////// /////=####018006592#### FXUS65 KPUB 041016 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 416 AM MDT Sat May 4 2024 .KEY MESSAGES... - Frost conditions will remain possible this morning over El Paso County. - Cooler conditions will help give a relief to the high fire danger today, while scattered showers with isolated thunderstorms develop mainly over the mountains. - Snow chances increase across the Continental Divide Sunday night into Monday, with periodic snow chances continuing through mid week. - Increasing winds and fire danger early next week with a trend towards cooler and wetter conditions for late week. && .SHORT TERM /THROUGH SUNDAY/... Issued at 403 AM MDT Sat May 4 2024 The cold front which quickly moved across the plains has since moved well to the south, with any remaining gusty winds staying confined to the far southeast plains early this morning. Precip across the southeast plains has also diminished early this morning, however, stratus has developed. While this stratus may continue to expand through the early morning hours, think the Frost Advisory across El Paso County still looks to be on track. Temps fell well into the 30s even with a stronger wind, and don't see why they won't fall or hold steady especially as winds further drop off. Cloud cover may limit frost development in some spots, but once again, think the Frost Advisory is on track and have left it in place at this time. A return to southwesterly flow is in store today, as an upper level low moves east across the western CONUS. This will usher in some weak mid level energy and slight increases in moisture that should be enough for scattered showers with isolated storms to develop over the mountains this afternoon. They should stay tied the higher terrain, but would not be surprised to see a few showers move off the mountains and into the valleys and adjacent plains. Severe weather is not expected today though, as instability looks to be on the weaker side. Additionally, some light snow accums will be possible for the higher peaks this afternoon into the early evening. Despite sunny to partly cloudy skies through midday and early afternoon along with some warming, overall cooler air mass will keep temps cooler and slightly below normal today. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 403 AM MDT Sat May 4 2024 Sunday-Monday...Models remain in good agreement of increasing southwest flow aloft across the region through the day Sunday, as a strong eastern Pacific low, currently moving onshore across the Pacific Northwest Coast, digs across the West Coast and into the Great Basin. This system remains progged to weaken as it lifts out across the Rockies through the day on Monday, however, its associated strong mid level (bora) front is progged to translate across south central Colorado early Monday morning and continues out across the Eastern Plains through the late morning and early afternoon. The progged movement of the this system keeps much of southern Colorado in the dry and windy portion of the storm, with breezy south to southwest winds of 20 to 40 mph expected across the region by Sunday afternoon, strongest over the higher terrain. There could to be some spotty critical weather conditions across the San Luis Valley on Sunday, however, current coverage looks to preclude any fire weather highlights attm. Temperatures warm ahead of the system on Sunday, with highs back to at and above seasonal levels in the 70s to lower 80s across the Plains, and mainly in the 50s and 60s across the higher terrain. Increasing moisture and lift ahead of the system moving across the Rockies Sunday night will develop snow across the Continental Divide, with snow, heavy at times, and blowing snow likely creating hazardous travel across the higher mountain passes into Monday morning. While current snow amounts fall short of advisory levels, later shifts may need to issue some highlights for the expected snow and blowing associated with the passing bora front. Further east, will see increasing west to southwest winds ahead of the front Sunday night, with strong westerly winds of 40 to 60 mph, strongest over and near the southeast mountains, possible as the bora front translates east early Monday morning. Will need to keep monitoring later model data with later shifts possibly issuing High Wind Watches, as well as Fire Weather Watches for areas where fuels are deemed critical, with very dry air mixing down across the region on Monday. Temperatures cool behind the bora system on Monday, though are still around seasonal levels in the 60s to mid 70s across the Plains, and in the 40s and 50s across the higher terrain, save 30s at the peaks. Moderate westerly flow continues across the region Tuesday and Wednesday, keeping mainly dry, save for some showers across the ContDvd, breezy and warm conditions in place through mid week, with the potential for critical fire weather conditions, especially across the San Luis Valley. Cool and unsettled weather remains in the offing for Wednesday night through the end of the work week, as models continue to indicate a broad upper trough in place across the Rockies. This will allow for a few fronts to move across the region, as well as support shower chances, especially over and near the higher terrain. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 403 AM MDT Sat May 4 2024 COS and PUB...low VFR to MFVR (bkn030-060) across the terminals through the early morning hours, as easterly upslope flow develops behind last nights passing front. VFR conditions to prevail through the late morning and the rest of the taf period, with scattered showers developing and remaining over the higher terrain this afternoon. Breezy east to southeast winds 15-20kts expected at the terminals this afternoon. VFR conditions expected at ALS over the next 24 hours, with breezy south to southwest winds of 15-20kts expected in the afternoon. Showers to develop over the higher terrain through the afternoon, with too low a probability of showers at the terminal to include attm. && .PUB WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 9 AM MDT this morning for COZ084-085. && $$ SHORT TERM...RODRIGUEZ LONG TERM...MW AVIATION...MW