####018006709#### FXAK69 PAFG 100010 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 410 PM AKDT Thu May 9 2024 .SYNOPSIS... Shower chances will persist over the next several days. A combination of rain and snow showers are expected over the Yukon Delta, Seward Peninsula, and areas along the Arctic Coast. Locations farther inland and at lower elevations can expect mainly rain showers. There is a small chance of thunderstorms over portions of the Interior both north and south of the White Mountains through this evening. Storm chances for Friday will push a little farther north, primarily over the Yukon Flats. Strong southerly winds aloft will translate to strong southerly gap winds of 15 to 30 mph with gusts to 45 mph expected near Delta Junction and the eastern Alaska Range Friday night and Saturday morning. && .DISCUSSION... Model Analysis... 12Z deterministic models appear to have initialized better than the 00Z set. At 500mb GFS, NAM, and ECMWF were still 2 dam (decameter) too low over northwest Alaska compared to the 12Z radiosonde flights and matched up well with the upper-level low over the eastern Aleutians. Inverted trough arced from the eastern Aleutian upper low over the Bering Sea west of the Yukon Delta to to northeast Russia. A trough of low pressure, remnant of an filling upper low, jutted northward over the Seward Peninsula into northwest Alaska. Lobes of vorticity were noted near Utqiagvik and over the Alaskan Panhandle which will continue to propagate cyclonically around the state, which will lead to enhanced forcing for ascent. At the surface at 12Z, several areas of low pressure were identified. A broad area of low pressure stretched from near Norton Sound eastward across the Interior. Satellite imagery revealed several focused circulations near Galena, Rampart, and near Fort Greely. Expect those areas of low pressure to slowly strengthen today and rotate cyclonically north and eastward. Look for enhanced shower potential and a few thunderstorms this afternoon. Today through Saturday... Diurnal showers and a few thunderstorms will continue to percolate through this evening over the Interior. Mixed layer CAPE values a high as 100-150 J/kg is forecast from the north slope of the Alaska Range as far north as the White Mountains and Yukon Flats. Hodographs over that area are straight in the lowest 3 km with around 30-35 knots of 0-3km shear. Tall skinny CAPE profile in conjunction with falling heights aloft should be sufficient for a few thunderstorms. A heavy shower passed over our office a few hours ago and produced very small hail. Expect a few of the stronger cells to be capable of small hail in addition to a few lightning strikes. As sun angle lowers later this evening, instability will diminish and showers will gradually weaken. Portions of Northwest Alaska, generally south of Utqiagvik to Nome and Unalakleet will be under the northern lobe of vorticity and should continue to see overcast skies and light snow. Snow accumulations of 1 to 4 inches are expected. In the wake of the upper trough from Utqiagvik east along the Arctic Coast have seen forcing for ascent and clearing skies. Lower snow totals are expected over the Yukon Delta as temperatures will trend warmer. A few spots may pick up an inch or two, particularly in the higher elevation areas. The broad upper level pattern will continue to see cyclonic flow aloft. The light snow over Northwest Alaska will push out over the Chukchi Sea and the Bering Straight. Diurnal showers are forecast again for the Interior Friday. A few thunderstorms are forecast again, although the focus will be farther north, generally north of the White Mountains and across the Yukon Flats. South of the White Mountains, isolated to scattered showers are expected. Another surge of stronger winds aloft will arrive over the Alaska Range Friday afternoon and evening which will generate gap flow through the passes. The strongest winds will be found from Isabell Pass to Fort Greely and Delta Junction where winds of 15 to 30 mph and gusts to 45 mph are forecast Friday night into Saturday morning. An upper-level trough will accompany those stronger winds and will arrive over the eastern Interior and the ALCAN border Saturday afternoon. Another day of showers and perhaps a few thunderstorms are forecast for the Yukon Flats. Extended Forecast Days 4-7... Model guidance continues to indicate persistent broad upper level troughing over most of the forecast area throughout the extended forecast period. Periodic intrusions of ridging from Canada into the eastern Interior are also suggested. This pattern will continue to support scattered.. showers across much of northern Alaska. Model solutions gradually disperse Sunday and beyond, suggesting lower than average overall confidence in the forecast beyond Day 3 Saturday. Coastal Hazard Potential Days 3 and 4...None. .FIRE WEATHER... High temperatures in the 50s to near 60 through Friday. Scattered to numerous showers this evening throughout the Interior as a disturbance moves through the region tonight. Slight chance of thunderstorms this afternoon and early this evening over the Fairbanks area and the Yukon Flats north of the White Mountains. The thunderstorm threat will shift north for Friday with areas in the Yukon Flats seeing the greatest potential for storms, around 5 to 10 percent. Isolated to scattered showers will remain throughout the weekend as more disturbances move through the area. Southerly gap winds of 15 to 30 mph with gusts to 45 mph are forecast Friday night and Saturday morning from Isabell Pass to Delta Junction areas. Near-critical fire weather conditions are possible with RH values of 35 to 25 mph. && .HYDROLOGY... The breakup front on the Yukon river is approaching Circle and expected to reach Circle in the near future. As of 7 pm Wednesday, an ice jam was in place 12 miles upriver from Circle with some overbank flooding of low areas with no water over higher banks. Downstream of Circle, small sloughs and streams are clearing of ice, but the main channel of the Yukon still has ice in-place. The Tanana and Upper Kuskokwim River are mostly open. Rivers north of the Yukon River have mostly intact ice. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...Flood Watch for AKZ833. PK...Heavy Freezing Spray Warning for PKZ806. && $$ Huyck ####018005195#### FXUS63 KMPX 100010 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 710 PM CDT Thu May 9 2024 .KEY MESSAGES... - Frost/Freeze likely across portions of northwest Wisconsin tonight. - Scattered thunderstorms, some potentially severe, Friday afternoon across eastern Minnesota & western Wisconsin. - Above-normal temperatures this weekend into next week. && .DISCUSSION... Issued at 249 PM CDT Thu May 9 2024 Isolated showers and blanketing stratus across western WI and southern MN continue to retreat to the south as surface low pressure progs east over the upper-Ohio River Valley region. Aside from remnant scattered cu developing from peak daytime heating, temperatures are expected to reach the mid to upper 60s. Tonight's forecasted lows will widely range from the upper 40s in western MN to near freezing in portions of interior west-central WI. Northeasterly flow combined with clearer skies will allow for some areas in WI to see potential frost Friday morning. So if you have any vegetation that is sensitive to temperature, you may want to consider taking protective measures. The main course for today's discussion focuses on the forecast for Friday. An upper-level shortwave over Saskatchewan and Manitoba descends south over the northern plains beginning Friday morning. NW winds will increase between 30-35 mph across western MN as it lays on the periphery of the pressure gradient. Best forcing for precip development looks to reach central MN and Western WI by Friday afternoon. Consistent with the previous discussion, timing of forcing arrival aligns with peak diurnal heating, thus an increased potential of organized convection. The Storm Prediction Center has issued a marginal risk (level 1 of 5) for severe convection Friday afternoon and evening. Forecast soundings present an environment of only a few hundred joules/kg of elevated MUCAPE and inverted-V soundings. Therefore hazards look to mainly be limited to isolated strong gusty winds and potentially some hail in the strongest storms. QPF as of now looks to range between a few hundredths to a quarter of an inch with Western WI have higher confidence of observing near the quarter inch mark. Storms will quickly clear out Friday overnight with lows in the 40s. This weekend looks overall relatively quiet as the northern plains falls under split flow. Winds will remain slightly increased with gusts up to 25 mph along with RH values nearing 30 percent, elevated fire weather conditions will exist. Saturday will be a great day to get outside and enjoy temperatures in the upper-60s to mid-70s with only scatted afternoon cu to disrupt plentiful sunshine. Sunday, the maxima of the h85 thermal ridge will advect east and allow highs to reach the low 80s for much of the area. A weak shortwave develops over the Dakotas Sunday afternoon which could potential generate a few showers however there is disagreement amongst long-term ensemble membership, thus maintained NBM PoPs of 30 percent mainly east of the I-35 corridor. Looking into early next week, multiple shortwaves bring periods of precipitation although QPF advertising only light rainfall accumulations. An upper-level wave sweeps across the Northern CONUS by the middle of next week which could be bit more robust but will need to continue monitoring. Temperatures will range near climatology for this time of year which is in the upper 60s. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 645 PM CDT Thu May 9 2024 Areas of mid-level cumulus will continue to move south and scatter out this evening, resulting in mostly clear skies until our next small system approaches from the northwest tomorrow morning. Chances for scattered showers and thunderstorms increase for east-central Minnesota and western Wisconsin in the mid-late afternoon, lasting through the early evening. The main threat with any thunderstorms will be strong winds, but isolated small hail is not out of the question for the strongest storms. Winds will be light and variable tonight, increasing to 5-10kts from the SW in the morning, and ultimately shifting out of the NW being the fropa in the afternoon. Gusts up to 25-30kts are possible in the afternoon, especially for terminals located in Minnesota. KMSP...Most likely timing for thunderstorms looks to be within the 20-23z timeframe. Any showers and storms will be scattered, allowing conditions to improve and decline quickly during the afternoon. Expect gusts up to 40+kts with any stronger storms that pass through. /OUTLOOK FOR KMSP/ SAT...VFR. Wind NW 10G20 kts. SUN...VFR. Wind W 15G25 kts. MON...VFR. Wind variable 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...Frost Advisory from 2 AM to 8 AM CDT Friday for Barron- Chippewa-Eau Claire. Freeze Warning from 2 AM to 8 AM CDT Friday for Rusk. && $$ DISCUSSION...Dunleavy AVIATION...BED ####018007680#### FXUS61 KRLX 100013 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 813 PM EDT Thu May 9 2024 .SYNOPSIS... A cold front will bring additional showers and storms this evening, with some storms becoming strong to severe, before promoting cooler weather for Friday and the weekend. && .NEAR TERM /THROUGH FRIDAY/... As of 750 PM Thursday... Scattered strong thunderstorms have developed across portions of the forecast area this evening in advance of and along a cold front, with isolated severe storms possible over the next few hours. The main threats continue to be damaging wind gusts, hail, and localized flash flooding, with the northeast portion of the CWA having the greatest chance for impacts. Some weak rotation has been noted with the cells this evening, so an isolated, brief spin-up cannot entirely be ruled out. Activity will continue to quickly shift southeastward over the next few hours, with the severe threat quickly diminishing/exiting from ~ 10 PM to midnight. Have updated PoPs, temperatures, and cloud cover throughout the night to represent the latest trends. The rest of the forecast remains on track. As of 220 PM Thursday... Showers and thunderstorms are likely to fire up this afternoon, as west to southwest low level flow increases ahead of an approaching low pressure center and cold front. This will begin with isolated to scattered activity this afternoon, followed by a segmented line of convection drifting southeastward this evening into tonight. Clouds were limiting heating across much of the middle Ohio Valley, versus areas nearer and in the mountains. With the opposite pattern in terms of bulk shear, near 60 kts west but down around 40 kts east integrated 0-6 km, overall severe potential is marginal. Also, modest low level storm relative helicity peaking in the 150-200 m2/s2 range will also support some rotation in more organized cells, like within any line segments later on. Pockets of one hour flash flood guidance values of an inch or less, particularly over the middle Ohio Valley, make such areas vulnerable to excessive runoff from any heavier thunderstorm, but vegetation nearing full growth has proven to be a mitigating factor this week. Cooler air and low clouds roll in behind the cold front tonight, and Friday will be a noticeably different day with the low overcast in place. Showers are possible in the afternoon as a mid-upper level short wave trough crosses, but instability, if any, will be limited. After one last warm afternoon for a few days, central guidance reflects cooling from northwest to southeast behind the cold front tonight, and a noticeably cooler day on Friday with lower 60s most of the afternoon across the lowlands, actually below normal for this time of year. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 225 PM Thursday... Precipitation ends from west to east Friday night as transient ridging builds into the region ahead of a northern stream disturbance approaching during the day Saturday. With relatively cool air left in the wake of the Friday system along with relatively early arrival of associated cloudiness, won't realize very much surface heating. Still, should be able to generate some conditional instability, perhaps 500J/kg in the presence of rather stout deep layer shear of 40 to 50KTs by Saturday afternoon. With rather cool air aloft, graupel showers are likely, with some stronger cores also possible yield strong to perhaps marginally severe wind gusts. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 225 PM Thursday... Ridging building into the region yields mainly dry conditions from late Sunday afternoon through Monday. Deep southwesterly flow associated with the next southern stream system will begin to advect moisture back into the region Monday afternoon into Monday evening. Upper level forcing arriving late Monday afternoon into early Tuesday morning will yield an uptick in precipitation coverage. Given the low amplitude of this feature and varied model timing, confidence is not especially high. Transient ridging builds back into the region briefly Wednesday before another system arrives Thursday. Severe risk through this period appears low given a relatively weak flow regime. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... As of 220 PM Thursday... Stratocumulus has scattered out or lifted out of MVFR for the most part, although brief MVFR ceilings are still possible this afternoon. Showers and thunderstorms are likely to fire up this afternoon, ahead of a low pressure system and cold front, already producing scattered showers in east-central Ohio early this afternoon. MVFR to briefly IFR conditions can be expected directly beneath any thunderstorm, with gusty winds also possible in and near the storms. Showers and thunderstorms will diminish after sunset, but onset and ending timing will generally be earliest northwest /PKB/ and latest southeast /BKW/, as the low pressure system and cold front progress southeastward through the area tonight. Stratocu will lower to MVFR and then even IFR behind the cold front overnight tonight, with MVFR ceilings persisting through Friday morning. BKW may not quite lower to IFR until the end of the TAF period, 18Z Friday. There may also be MVFR visibility in mist/drizzle overnight into Friday morning, possibly lowering to IFR at times. Light southwest flow, albeit with the occasional gust here and there, ahead of the cold front this afternoon will become west to northwest behind it tonight, and become a bit gusty at least at BKW by dawn Friday. Moderate west to southwest flow ahead of the front this afternoon will become moderate west to northwest behind it tonight, and then light northwest on Friday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of ceiling and visibility restrictions may vary from forecast. Winds will fluctuate. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE FRI 05/10/24 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H H H H H H M HTS CONSISTENCY H H H H H M H H H H M M BKW CONSISTENCY H H H H H H H H M M M H EKN CONSISTENCY H H M H H H H H M H H L PKB CONSISTENCY H H M M M H H H H M H M CKB CONSISTENCY M H H M M L H H H H H H AFTER 00Z SATURDAY... Lingering IFR conditions behind the cold front remain possible along the mountains Friday afternoon. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/JP/GW NEAR TERM...TRM/GW SHORT TERM...JP LONG TERM...JP AVIATION...TRM