####018006858#### FXUS63 KARX 221656 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 1156 AM CDT Mon Apr 22 2024 .KEY MESSAGES... - Elevated fire weather conditions across parts of Wisconsin before rain chances increase later today. - Strong winds from the southwest 30 to 40 mph developing today ahead of a cold front. - Light rain amounts later today into Tuesday, with a stormier, wetter period Thursday night into early next week. - Frost/Freeze Wednesday morning. && .DISCUSSION... Issued at 400 AM CDT Mon Apr 22 2024 Overview: Starting out a little milder today with light and variable or light southwest winds and temperatures in the 20s, 30s, and 40s. Water vapor satellite imagery and heights early this morning showed a mid tropospheric ridge with some high clouds spilling into the area. An area of closed low pressure was centered over Saskatchewan. Today through Tuesday night: The closed low will move into the region today breaking down the ridge and swinging through the Northern Plains and Upper Mississippi Valley through Tuesday evening. Moisture transport across the Plains increases across western Iowa this morning and toward the Mississippi river through 00Z, then shifts east of the area by 06z with wrap-around moisture Tuesday. A strengthening low level jet ahead of the cold front across Iowa will transport warm air northeastward with temperatures warming into the 60s. Meanwhile, a strong 100kt jet will push into the Rockies and Plains. With the ascent, warm air advection, and moisture transport, clouds will be on the increase with some showers developing. Initially, precipitable water is 25 to 50% of normal, however by 23.00Z increases to 125 to 150% of normal. Initially the dry low levels and approach of the storm system will favor deeper mixing, however with the increasing clouds, this will work against optimizing mixing. Seeing some differences in how strong the southwest winds will be. The 35 to 45kt low level jet over western Iowa/central MN around 18Z shifts eastward during the afternoon and increases to 40-50kts as it moves into southwest WI during the evening. The HREF probabilities of 26kts winds are only 10 to 20%, however the HRRR/CONSShort forecasts have 23-25kts across our western counties with the ADJLAV/GLAMP data in the 25-30kt range. Some mixed signals on the winds, but there will be a strong cross-wind component along I90 and potential for additional gustiness with the virga and light precipitation in the area. In coordination with MPX/DMX included parts of southeast MN and northeast IA in a wind advisory for later this morning and much of the afternoon. The wind vectors become less unidirectional as the stronger winds aloft shift into Wisconsin, so we'll need to monitor how effective the stronger winds are mixing down during the day and as they shift east this evening. Virga and a few showers increase through the day with the warm advection and moisture with showers becoming more likely along and north of I94 this evening. Rainfall amounts should be light with the greater probabilities of 0.05" or more north of I94 (50-80%). We should see a break overnight with the re-enforcing cold front and upper level trough swinging through later morning into the afternoon. Some instability 50 to 250J/kg attends the upper level trough Tuesday, thus have thunder mentioned. Again precipitation amounts should be on the light side with 30-60% probabilities of 0.10" across parts of WI. See Fire Weather section for elevated fire weather details. Frost/Freeze Potential Wednesday morning: Skies clear for Wednesday morning with diminishing winds. The cold airmass shows the potential for temperatures to drop back into the 20s and lower 30s for much of the forecast area again. EC/Canadian/GFS ensembles show a 30 to 90% probability for a low of 32 or colder with the higher probabilities north (MDZ) and lower probabilities toward DBQ. Thursday night into early next week: We continue to see trends of a pattern change and active weather setting up from Thursday night into early next week. A series of troughs are forecast to move into the Plains and head toward the Mid and Upper Mississippi Valleys. The first area of 500mb low pressure tracks across the Central Plains and heads toward MN/Upper MI. This pattern lifts a warm front into our region with periods of showers and thunderstorms Friday into Saturday. The location of strong to severe storms will depend on how the track evolves. We currently have highs in the 60s Friday with 60s and 70s forecast for Saturday. The next storm system Sunday into Monday again affects a large portion of the Midwest, but there are some large differences in strength. Strong winds are currently forecast to accompany the storm system Friday. Over the course of these two storms, widespread rains are expected and some initial estimates have 1.5"+ over a large area of the Midwest. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1156 AM CDT Mon Apr 22 2024 VFR conditions will persist through this TAF cycle with a period of mid-level ceilings later this afternoon into early and scattered light showers (30-60% chance). Southerly winds gusting 25 to 35 kts will diminish and become westerly overnight behind a front. A brief period of low-level wind shear could occur this evening if surface winds slacken before the low-level jet moves east. Additional scattered showers/isolated storms are possible Tuesday afternoon, with the higher chances across parts of Wisconsin. Winds will become gusty from the west to northwest behind a secondary front on Tuesday. && .FIRE WEATHER... Issued at 400 AM CDT Mon Apr 22 2024 Ahead of a cold front today, a dry airmass is in place with strengthening southwest winds and warming temperatures into the 60s. Lowest relative humidity values drop to 20 to 30 percent through mid afternoon, then improve with increasing rain chances. Fuels have increased with some drying over the last couple of days and the warmer temperatures today. Due to the strong winds developing from the southwest with gusts 30 to 40 mph, burning should be avoided due to the elevated fire weather conditions. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...Wind Advisory until 5 PM CDT this afternoon for MNZ086-087-094- 095. IA...Wind Advisory until 5 PM CDT this afternoon for IAZ008>010-018- 019-029. && $$ DISCUSSION...Zapotocny AVIATION...JM FIRE WEATHER...Zapotocny ####018004907#### FXUS64 KOUN 221657 AFDOUN Area Forecast Discussion National Weather Service Norman OK 1157 AM CDT Mon Apr 22 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 356 AM CDT Mon Apr 22 2024 Highlights: * Very localized ground fog this morning * Breezy this afternoon * Elevated fire weather northwest this afternoon The surface ridge is moving east out of the area this morning, Southerly low-level flow has returned to all but southeast Oklahoma early this morning, but there are some areas where winds are still light. Ardmore and Lawton weather stations are reporting reduced visibilities as of 08Z, although no widespread areas of fog are apparent on satellite or Lawton area traffic cameras, so these may be cases of localized ground fog. Will watch trends, but do not anticipate anything more than localized ground for at the moment. Winds will increase by about 14-15Z and become breezy today (especially in the northwest) as the pressure gradient tightens in response to a surface low developing in southeast Colorado. These winds and continued drought in parts of northwest Oklahoma will elevate fire weather conditions this afternoon, although forecast humidity remains above 20 percent, so conditions should not become critical. && .LONG TERM... (Tuesday through Sunday) Issued at 356 AM CDT Mon Apr 22 2024 Highlights: * Transition to a more active/stormy pattern mid to late week. * Some severe potential Tuesday and Wednesday. Higher severe potential later this week. * Near-critical Fire Weather conditions west on Friday and perhaps Saturday. A mid-level trough moving from the northern Plains toward the Great Lakes tomorrow help nudge a cold front down the central Plains and likely into Oklahoma on Tuesday. Although there still is some question about the cap strength initially, the GFS and a number of CAMs show convection developing in the southwest near the front by 00Z. Instability would be sufficient for the potential of isolated severe storms during the late afternoon and early evening. As the front stalls out, isentropic lift above the front will develop increasing storm chances somewhat Tuesday night into Wednesday, although these storms would be elevated with lower severe weather potential Tuesday night into early Wednesday. But as the front finally lifts north, instability will increase again across the area bringing at least the potential for isolated severe storms back late Wednesday afternoon and into the nighttime hours. Meanwhile, a larger scale mid-level trough develops over the Western United States on Thursday and brings moving toward the Plains. The models are becoming more consistent with the timing of this trough affecting the area with the trough axis moving over the High Plains overnight Thursday night. With this current forecast timing, thunderstorm potential increases again late Thursday afternoon and evening with storms spreading east overnight and into Friday. There will be a respite in storm chances behind this wave, but another large-scale mid-level trough develops in the West Friday/Friday night and moves towards the area either Saturday (per the ECMWF) or Saturday night/Sunday (per the GFS) increasing storm chances once again. With these systems moving through, a dryline is expected to move into western Oklahoma on Friday, and perhaps again on Saturday. This will bring very low dewpoints and humidity into western Oklahoma and western north Texas and create elevated to near- critical fire weather conditions, especially again in the areas of northwest Oklahoma that have not received significant rainfall recently. && .AVIATION... (18Z TAFS) Issued at 1152 AM CDT Mon Apr 22 2024 Gusty south/southwest winds will continue through the afternoon with perhaps a few high-based cu. Winds will diminish some this evening, but remain breezy. Even with these winds LLJ will strengthen sufficiently for LLWS to be a concern overnight everywhere but DUA. Southwest winds will again increase Tuesday morning. A cold front will enter northwest Oklahoma and will shift winds to the northwest at WWR mid-morning. There will also be some MVFR ceilings at DUA Tuesday morning. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 70 54 81 57 / 0 0 10 30 Hobart OK 72 52 83 56 / 0 0 10 30 Wichita Falls TX 71 53 83 60 / 0 0 20 30 Gage OK 78 54 79 49 / 0 0 0 20 Ponca City OK 73 53 79 51 / 0 0 10 20 Durant OK 69 52 78 61 / 0 0 0 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ SHORT TERM...26 LONG TERM....26 AVIATION...30 ####018008390#### FXUS63 KDTX 221658 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1258 PM EDT Mon Apr 22 2024 .KEY MESSAGES... - Warming trend continues today with dry and sunny conditions. - Showers arrive late tonight with possible thunderstorms Tuesday afternoon and evening. - Strong winds of 30 to 40 mph will be possible in the Thumb late Tuesday night and Wednesday. - Dry and cool weather is expected Wednesday and Thursday - Periodic rain and/or thunderstorm chances are expected to develop late Friday through the upcoming weekend as an upper level trough pushes across the region. Low confidence exists in the timing of rain activity. && .AVIATION... Upper clouds will thicken late in the day as a ridge of high pressure shifts east of the region. Increased southwesterly flow between this departing ridge and an approaching cold front will bring a steady increase in moisture late tonight into Tuesday with light showers working into the area 08z-10z and persisting for 4 or 5 hours. Ceilings through 18z Tuesday should remain lower VFR. Wind gusts near 20 knots are expected this afternoon with 20-25 knot gusts again from late tonight through Tuesday within the tightening pressure gradient. DTW THRESHOLD PROBABILITIES... * Low for ceilings aob 5kft late tonight, medium on Tuesday. && .PREV DISCUSSION... Issued at 1033 AM EDT Mon Apr 22 2024 UPDATE... In accordance with neighboring offices, a Red Flag Warning has been issued for Midland, Bay, and Saginaw counties for today. Main factor in issuance is the dry fuel in that part of the state. Daytime heating pushing temperatures into the mid-60s today coupled with drier air moving in and dropping dew points below 30 degrees this afternoon brings RH values down just enough to meet criteria. Winds southwest at 15 mph also increases the fire risk today. Dew points increase beginning at 0Z tonight ahead of rain showers tomorrow coupled with temperatures dropping below 50 tonight bring the area safely out of Red Flag Criteria overnight. PREV DISCUSSION... Issued at 351 AM EDT Mon Apr 22 2024 DISCUSSION... A weak backdoor cold front is now working southward through Southeast Michigan this morning. Windspeeds actually become calm behind the front whereas much of Southeast Michigan has carried a light southwest to west wind overnight. The Frost Advisory remains in effect until 8 AM as there should be a good amount of cooling yet this morning with surface dewpoints running in the mid to upper 20s. Differential anticyclonic vorticity advection occurring over the Ohio River Valley will then allow surface high pressure to extend northward and strengthen over the Central and Eastern Great Lakes. This will allow for a reemergence of southwesterly wind of 10 to 20 mph today. The arrival of an upper level jet streak concurrent with the increase in midlevel warm advection will support synoptic scale ascent through the Central Great Lakes late tonight. Forecasted isentropic analysis and plan view of RH progs suggests the depth of favorable moisture late tonight will be compromised. The best of sub 700mb moisture is forecasted to reside across the Saginaw Valley northward to the Straits, whereas better midlevel moisture tracks through Metro Detroit. Expectations are for a band of light showers or sprinkles to pass through between 09-12Z before modest convergence axis then settles and stalls out Downriver to the Ohio border by late morning. Did take the opportunity to try and time out the initial shower activity late tonight and introduce a dry period Tuesday morning. Combination of convergence with progressive evolution to zonal upper level jet axis is forecasted to result in an ageostrophic response and zone of frontogenesis very close to the Ohio Michigan stateline during the day on Tuesday. Hires model consensus keeps much of the Michigan side dry while a frontal wave brings prevailing stratiform rain to northern Ohio. The ECMWF is offering a differing solution that does clip the southern forecast area for a period of time 12-18Z Tuesday. The last piece to this Tuesday system will be the deep trough axis and height falls that dig southward into Southeast Michigan between 21-06Z Tuesday afternoon/night. Forecast soundings and moisture progs show a drier airmass is now expected which will offer some slight instability during the late day period due to the dry adiabatic lapse rates. So, confidence has increased in a better potential for modest thunderstorm activity. Marginal instability will exist with MUCAPES of 250 J/kg or less. A possibility with convective activity late Tuesday will be small hail as freezing heights will be low at approximately 5.0-6.0 kft agl. One of the more interesting aspects of this system will be the potential for a strong wind response late Tuesday night across the Thumb. The potential will exist for north winds of 30 to 40 mph for a time, particularly along the Lake Huron shoreline. Storm total QPF amounts from late tonight through Tuesday night are expected to be 0.25 to 0.33 inch. Low level cold advection and strongly anticyclonic flow trajectories will result in high stability over the region Wednesday through the day Friday. The narrative for this quiet period will be the potential for cold temperatures Wednesday morning and again Thursday morning. The signal is quite high that temperatures across all of the forecast area will be down into the 20s Thursday morning. Will likely need a Freeze Warning for Wednesday night/Thursday morning for Southeast Michigan. The other curiosity for Thursday, is what sort of lake breeze response will occur off of the Lake Huron/Lake St Clair aggregate into Downtown Detroit. Difficult to say given the pervasive southeast wind direction that should be in place during the afternoon. So may not see an actual lake breeze release, but conditions are likely to be chilly, regardless, with dewpoints in the 20s Thursday evening. From this vantage point, the Friday to Saturday period is a forecast of low predictability as models are trying to resolve how a deep trough will migrate into and then eject out of the western United States. A very high amplitude to this trough brings very low confidence in temporal details with the latest model trends now supporting two separate, strong low pressure centers. Confidence is relatively high in an unsettled, wet period Friday night and Saturday with a strong warm advection response targeting the region. Latest indications suggest the warm air advection will remain progressive across the region Friday night. The difficulty will be trying to pin down dry periods on Saturday as downstream ridge amplification should occur in advance of the trailing Southwest United States PV anomaly. MARINE... A ridge axis gets displaced toward the east this afternoon as a closed upper low over Saskatchewan merges with an adjacent jet into The Dakotas. This backs winds south-southwesterly downstream with enhanced flow across Saginaw Bay and Lake Huron. The warm advective regime limits gust potential to below 25 knots. The low then crosses into central Ontario late tonight providing a marked uptick in gradient flow. Speeds should reach Small Craft Advisory criteria after midnight for Saginaw Bay before becoming more widespread across most of the central Great Lakes on Tuesday. This system also yields a period of showers and a few thunderstorms. A cold front then drops through Tuesday night leading to brisk northerly flow on Wednesday with some low-end potential for on-shore gales. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...Red Flag Warning until 8 PM EDT this evening for MIZ047-048-053. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....DG UPDATE.......BC/MV DISCUSSION...CB MARINE.......KGK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit. ####018009332#### FXUS66 KPDT 221659 AAA AFDPDT Area Forecast Discussion...Updated National Weather Service Pendleton OR 959 AM PDT Mon Apr 22 2024 Updated aviation discussion .UPDATE...Mostly clear skies this morning will slowly give way to increasing high clouds through the day and persist overnight. This should be enough to keep temperatures above freezing around the Lower Columbia Basin. However, continued protection of sensitive plants would be wise as cold prone areas could still flirt with near freezing temperatures overnight. Morning update was made to adjust overnight temperatures down slightly and reduce cloud cover for most of the forecast area this morning to clear. && .AVIATION...18Z TAFs...VFR conditions are expected through the period with only cirrus clouds streaming through the area. However, KPSC will continue to experience MVFR CIGS/VSBYs due to smoke from a nearby factory fire. Winds should turn more northerly by early afternoon pushing the smoke south. Winds will be 10 kts or less. Earle/81 && .SHORT TERM...Today through Wednesday...Current radar shows not a thing happening over the CWA along with nighttime satellite imagery is showing mostly clear skies with some high thin cirrus lingering around Deschutes, Crook and Grant counties. With the exception of the nearly full moon, it is a perfect night for watching the Lyrid meteor shower to the northeast. The short term will be dominated by an upper level ridge through early Wednesday. Dry conditions will linger through Tuesday night before an upper level trough makes its way onshore. Precipitation will return to the mountains while the remainder of the CWA will remain dry. Models are in relatively good agreement today through Tuesday afternoon with the upper level ridge remaining overhead. Conditions will remain dry with mild temperatures across the area. 63% of the raw ensembles show temperatures to be in the low to mid 60s for the majority of the lower and highland elevations with over 50% showing the higher elevations around Ellensburg and Meacham seeing high 40s to low 50s. Tuesday will be the warmest day of the period with temperatures will be 2-5 degrees warmer with over 60% of the raw ensembles showing the foothills of the Blues in the mid to upper 60s, 50% show the Basin, Gorge and adjacent valleys in the upper 60s to low 70s, over 60% show central and north central OR in the upper 60s to low 70s, and lastly, 50% show the higher terrains in the upper 50s to low 60s. Models remain in good agreement with the incoming trough with the clusters showing the main variances being with the amplitude of the incoming trough. Deterministic guidance also shows a timing variance with the onset of the incoming precipitation. GFS has the precipitation reaching the WA Cascades early Wednesday morning, while the Euro has it arriving in the afternoon. Regardless of timing, 50-80% of the raw ensembles show 0.01 inches of rain to fall across the WA Cascades with POPs between 20-35%. Temperatures will decrease by 2-5 degrees and winds will increase due to the trough. Deterministic guidance shows a tightening of the pressure gradients across the Cascades as the trough moves over the mountains. NBM ensembles show 60-80% chance the Gorge, Simcoe Highlands and portions of the lower Columbia Basin will see sustained winds of 22 kts and gusts to 34 kts Wednesday night. Bennese/90 .LONG TERM...Thursday through Friday...An upper trough will be over PacNW as a cold front arrives with widespread precip Thursday. Friday into Saturday morning, precip lingers whereas the trough deepens but begins tapering off when PacNW is in between systems. Rain is expected with a 30-50% chance at the low elevations and a 50-60% chance at the crest of the Cascades Thursday morning, but <10% chance for Lower Columbia Basin of Washington. Chances of precip increases Friday when the cold front moves over the PacNW but decreases again Friday night into Saturday morning once the forecast area enters between systems (50-70% confidence). The cold front will bring moisture and enhance lift for thunderstorms to develop Friday late morning into the afternoon over the Blue Mountains and John Day Basin, but with a slim chance (15- 30%) due to low CAPE values. There seems to be a decent agreement with the occurrence of the trough over the PacNW Thursday but the depth and position differs onwards. 43% of GFS members favor the trough axis shifted more eastward and shallower, whereas the GFS shows it as slightly deeper and more West for Friday. For Saturday, the GFS shows the PacNW in between systems but other models have it in a trough. Clusters favors the trough over PacNW overall but has uncertainties within the depth are present There is good agreement on the troughing position shifting southeasterly. However, about 51% members favors a shallower trough over The Rockies but more of a zonal pattern over PacNW. Only 49% members agree on the rough deepening over The Rockies. It is difficult to forecast the precip due to not knowing how this trough will behave, lowering confidence in this weather pattern (30-40%). Simcoe Highlands and Central OR will be gusty at around 20-30 kts Thursday and Friday as the systems move over the region (>50% confidence). Temperatures remains near to above normal through the period. Feaster/97 Saturday through Monday...Guidance is in good agreement in the overall synoptic pattern over the weekend into early next week, with west-southwest flow aloft likely persisting. This is in response to an upper level low tracking through the Four Corners area as another slowly approaches the British Columbia coast. However, there are wide differences in both deterministic and ensemble solutions regarding timing, strength, and location of these synoptic features, which relate to differing rain chances, temperatures, and winds that can be expected during this timeframe. The primary weather concern resides with breezy conditions across the Basin, east slopes of the Cascades, Eastern Gorge, and the Simcoe Highlands Sunday afternoon, with both the ECMWF and the GFS highlighting elevated winds. Both are associated with an upper level shortwave that spins off the parent upper level low, still located off the southern British Columbia coast, but the low is much closer in the ECMWF solution which would lead to breezier winds. This closer upper low also provides more efficient moisture transport to provide higher chances of precipitation and rain amounts, with cooler high temperatures and slightly warmer overnight temperatures due to increased cloud cover. Sunday's shortwave does look stronger due to the proximity of the parent system, which leads to a higher potential for winds. Wind gusts of 15 to 25 mph are expected on Saturday afternoon, bumping up to 25-35 mph Sunday afternoon. Precipitation chances look to stay confined to areas at elevation over the Cascades and eastern mountains each day, peaking through the afternoon. Snow levels are consistent through the period between 4000 and 5000 feet, so any snowfall will only occur at higher terrain and stay below an inch. Rain amounts will stay below 0.10 of an inch each day, confined to areas above 4000 feet along the Cascades and above 2500 feet across the northern Blue Mountains. A weak transient shortwave overnight into Sunday morning looks to provide a brief respite in precipitation before the second shortwave passes through the area. High temperatures are expected to stay near or just below normal for this time of year, which is in the upper 60s to low 70s. West to southwest flow aloft is suggested by 73% of ensemble members over the weekend, which align more with the ECMWF solution of more efficient moisture transport than the GFS. Analyzing the strength and arrival of the trough is a little less clear cut, with 60-70% of ensemble members leaning toward a later arrival and stronger approaching low - which 52% of ensembles were expecting the opposite to occur just 12 hours ago. Due to these discrepancies, confidence is moderate (50-60%) regarding mountain showers, moderate (40-50%) for elevated afternoon winds, and low to moderate (30-50%) for below normal high temperatures each day. Thus, the NBM was utilized to provide an applicably weighted scenario. 75 && .PRELIMINARY POINT TEMPS/POPS... PDT 61 36 66 42 / 0 0 0 0 ALW 64 38 68 45 / 0 0 0 0 PSC 67 40 70 44 / 0 0 0 0 YKM 66 37 69 41 / 0 0 0 0 HRI 66 38 70 44 / 0 0 0 0 ELN 63 36 66 44 / 0 0 0 0 RDM 65 34 68 36 / 0 0 0 0 LGD 61 34 68 41 / 0 0 0 0 GCD 66 36 71 41 / 0 0 0 0 DLS 68 44 71 46 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...90 LONG TERM....75/97 AVIATION...81