####018005519#### FXUS61 KBGM 252311 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 711 PM EDT Thu Apr 25 2024 .SYNOPSIS... High pressure will be in control with dry weather through Friday. Northerly flow allows temperatures to fall below freezing again tonight. Saturday and Sunday, a warm front moves through bringing a chance of rain showers along with a warming trend. && .NEAR TERM /THROUGH FRIDAY NIGHT/... 7 PM Update... High pressure remains in control and the forecast is on-track. No changes needed at this time. 130 pm update... A large surface remains in control this period as it moves southeast to be centered over the area tonight then to the coast Friday and Friday night. The air with the high is cool and dry at the surface. Aloft a broad upper level trough over the northeast US will move east being replaced by a ridge centered over NY/PA Friday night. The low level flow out of the north and light this afternoon will become southwest Friday. Friday into Friday night warmer air will advect in. After 2 nearly clear days today and Friday, moisture will come in aloft late Friday night. With dry air, clear skies, and a calm wind temperatures fall tonight into the mid and upper 20s and lower 30s. Friday afternoon temperatures peak in the upper 50s and lower 60s. Friday night temperatures will be warmer again with lows mostly in the 30s. Winds will be light with dewpoint temperatures rising to around 30. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... 2 PM Update No significant changes to the short term with this update. A line of showers still looks to push through the area on Saturday, weakening as it moves east into a drier airmass. Rainfall amounts will be light; less than a tenth of an inch. Any filtered sun in the morning gives way to mainly cloudy skies for the afternoon and evening. Highs are near average in the upper 50s to mid-60s with a steady south wind 8-15 mph. A warm front pushes through Saturday night, and model guidance continues to show elevated instability moving in...this will keep scattered showers and isolated thunderstorms in the forecast overnight. Milder with lows in the 40s to low 50s as south winds continue 5 to 15 mph. Upper level heights continue to rise on Sunday, but there will be weak waves and instability around. The highest MLCAPE values remain confined to areas west of I-81, where up to 500 J/Kg is possible. Therefore, it will be partly sunny with scattered, mainly afternoon thunderstorms around. Went above the deterministic NBM, closer to the 50th percentile data...which gives highs in the 70s to even around 80 in the deeper valleys of the central southern tier region. The warm front continues to lift north Sunday night, and there could be a few lingering showers along it. Otherwise, it will be partly cloudy and warm with lows in the mid to upper 50s. && .LONG TERM /MONDAY THROUGH THURSDAY/... 2 PM Update Monday will be the warmest day of the week, and of the spring season so far. The forecast is trending drier, with more upper level ridging and capping on Monday. Therefore, decided to again go closer to the NBM 50th percentile for highs, as we are yet to hit full green up and the increasing sunshine should boost temperatures. Look for highs well into the 80s for most locations...with perhaps some upper 70s in the higher elevations of the Catskills still. Dew points reach the lower 60s, so it will certainly feel quite warm to even hot out there in the afternoon. The main low pressure system and cold front is modeled to move through the region Tuesday and Tuesday night. This will serve to bring us more widespread coverage of showers and thunderstorms ahead of the front. Instability on ensemble guidance is noteworthy, around 1,000 J/KG surface CAPE with dewpoints into the low 60's. In terms of any thunderstorm organization 0-6KM bulk shear is modeled to be around 30-40 knots ahead of the front which may lead to thunderstorm organization into linear segments with a gusty wind threat. Of course this far out timing of the front can have a big impact on instability. Lapse rates also look poor for any strong to severe storms too. So will continue to monitor over the next several days. Model guidance is showing a zonal to transient ridge pattern over the area for midweek; this will keep things mainly dry, but another frontal passage is possible either Wednesday or Thursday depending on how the timing works out. Temperatures are trending warmer, still well into the 70s for both Tuesday and Wednesday...it looks to finally cool back down closer to climo by the end of next week. && .AVIATION /23Z THURSDAY THROUGH TUESDAY/... High pressure remains in control for this period with VFR conditions expected at all terminals with mostly clear skies. Outlook... Friday night...VFR. Saturday through Monday...Restrictions possible in rain showers, especially in the afternoons and evenings. Tuesday...restrictions possible in rain showers and thunderstorms, especially in the afternoon and evening. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...ES/TAC NEAR TERM...MPK/TAC SHORT TERM...MJM/MWG LONG TERM...MJM/MWG AVIATION...MPK/TAC ####018010991#### FXUS63 KAPX 252311 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 711 PM EDT Thu Apr 25 2024 .KEY MESSAGES... -- Elevated fire danger Friday afternoon. -- Increasing confidence in rounds of showers and thunderstorms impacting northern Michigan from Friday night through Monday. -- Chance for severe thunderstorms, particularly later Saturday into Saturday night across northern lower Michigan. && .SHORT TERM /THROUGH TONIGHT/... High pressure still focused just to our east over Ontario...with PV maxima dropping across the CWA attm. Light and variable winds with lake breeze development today...and seeing a very few cu pop up over NE Lower, where some upsloping may be aiding in lift and saturation, combined with some slight moisture advection off the lake as that weak bit of PV moves through. Expecting high pressure to remain over the area tonight...though return flow should rotate into the region going into Friday morning, and especially Friday afternoon, with increasing warmth aloft, as well as an increase in overall moisture. However...southeast flow hangs on into Friday as well, and antecedent dry air mass should preclude most, if not all, precip from reaching the ground over the region till beyond this period. Primary Forecast Concerns: Increasingly warm and breezy, remaining dry...Expecting temps aloft to increase through the day Friday, and with mixing up to around 850mb, think highs in the upper 50s to lower 60s are quite probable, especially considering we should remain largely clear...and temps will not fall as much tonight as they did last night. With better downsloping over NW Lower...think some upper 60s could be possible as well...though I do have to admit that we should start to get better mid/high cloud coverage into that area with time in the afternoon. Current dry air mass will take time to saturate...and suspect this may hold off even some of the cloud cover until later in the afternoon/evening; even less can be said for precip, which should hold off till Friday night and beyond. Some suggestion that another lobe of lower dewpoints could pivot over the region from north to south Friday, which could allow for afternoon RHs to fall even further below the usual 25 percent criteria for fire weather thresholds. Have not gone quite this aggressive, but have elected to keep dewpoints (and subsequently, RHs) a touch lower even so. Additional concerns for fire weather as pressure gradient begins to strengthen with system tracking across the Plains; expecting 5-10kts sustained winds, which could gust as high as 20-25kts by evening. Admittedly, this is more of a warm advection setup for winds, which typically would not be as favorable for gustiness...though do think the antecedent dry air mass and good potential for mixing could aid in better gusts this time around...at least, while the sun is out. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Pattern Synopsis / Forecast: Active baroclinic zone will really get its act together over the course of the weekend as a complex setup of shortwaves and associated surface low pressure centers / frontal boundaries pass through the upper Great Lakes region, dispatching the dry influences of surface high pressure progged to be moving off the Atlantic coast of New England. The action begins Friday night as a surface warm front moves into the region, bringing a round of showers and potentially some thunder too. The next car in the metaphorical atmospheric train will be surface low pressure advancing east from Wisconsin into the U.P., drawing in a warmer and potentially much more unstable airmass before a surface cold frontal boundary moves into the region and sparks off another chance for showers and storms late Saturday, some of which could be strong to severe. This frontal boundary largely becomes stationary over the region by Sunday, continuing unsettled weather potential Sunday into Monday as yet another low pressure center works into the Great Lakes. The passage of this low pressure center should mark the end of the active stretch of weather, with surface high pressure progged to intrude into the Great Lakes as we move closer to midweek. Primary Forecast Concerns: Friday Night Convection: Despite warm / moist advection moving into the region, there will be some barriers to overcome as we progress into the overnight hours. Stout low level dry layer will impede the initial advances of a stratiform rain plume well ahead of the surface warm frontal boundary. It wouldn't be overly surprising for this plume to pass through the region with more of a whimper considering progged soundings display dewpoint depressions as high as 30 Celsius across the southwest part of the CWA around 00z Saturday. The most appreciable rainfall from this frontal passage will come later in the overnight when steepening lapse rates aloft (up to 7 Celsius / km) and 850mb warm advection drive elevated instability associated with the warm front. In theory, would like to see steeper lapse rates to drive instability up for better thunder coverage, but the moistening airmass should provide better rainfall potential for places that see repeated shower passages Friday night regardless. While instability is low (generally 100-400 J/kg), suppose an embedded rumble of thunder or two cannot be ruled out. Overall, looks like most spots probably see a general 0.25" or less Friday night, though localized areas that see repeated downpours could observe 0.75"+. At this time, severe weather potential looks quite low Friday night into Saturday morning. Saturday - Saturday Night: Uncertainty begins to riddle the forecast as we progress into Saturday, particularly with respect to the position of the surface warm frontal boundary. Most guidance has the surface warm front clearing the Straits and stalling out somewhere between the Bridge and the Soo, but there is a modest amount of guidance that has the front stalling out around the M-32 area. The former solution would generate more clearing / destabilization potential amid warmer temperatures across northern lower into the day Saturday, possibly as high as the upper 70s for some, while the latter solution brings about a cloudier and cooler solution (upper 50s and lower 60s) with a stable layer in the low levels and thus suppresses the majority of surface based convection to the south and west. Considering favorable low pressure position based off severe climo for northern Michigan and the 500mb ridge axis located just to our east, this in theory should allow for an easier warm frontal passage, despite the suppressing efforts of the colder Great Lakes. In the event that this solution pans out, this opens a Pandora's Box of convective potential across the region. Being in the vicinity of the triple point of the system will lead to favorable dynamics aloft to contribute to severe weather potential later Saturday into Saturday night as the surface low and associated cold front move into the region. Bulk shear increases considerably with the intrusion of the triple point (as high as 40-50kts). In addition, SRH values balloon above 200 m^2/s^2, indicating ample potential for rotating updrafts to materialize with any surface based storm that initiates. The final thing that will need to come together will be the maintenance of surface / low level moisture. Guidance wants to keep dewpoints well into the 50s and even into the lower 60s, which would lower cloud bases and bypass the potential suppressing nature of warmer air aloft in the profile. If we can achieve the higher end of this dewpoint range, coupled with the other aforementioned favorable dynamics, this could lead to all hazards being on the table Saturday evening / early overnight, with heavy emphasis on wind and hail (non-zero chance for these hazards to be locally significant if a more discrete / supercellular storm mode can be realized). Tornadic activity will be somewhat questionable owing to shear vectors being more parallel to the cold front as opposed to normal to the boundary as it approaches northern Michigan (thus leading to the eventual stationary nature of the front), but risk still remains non-zero. Additionally, the parallel relationship of shear vectors and frontal orientation could set up a heavy rain sequence with any potential training thunderstorms as PWATs swell to 1.00-1.25 (200-300% of climo normal). This setup has a very low floor, but a high ceiling that can't be overlooked despite ongoing forecast uncertainty. This is reflected by SPC already electing to place northern lower Michigan within the Day 3 Slight Risk (level 2/5) for the conditional threat of severe weather. Numerous more updates are to be had in the coming forecast cycles as details on the evolution of this sequence become clearer. Rest of the Period: The cold front will stall out overhead and become stationary by Sunday, and with additional disturbances expected to ride this area of forcing, this spells additional rounds of showers and storms at times Sunday into Monday, bringing additional rainfall. Eventually, low pressure will pass through the region and the stalled front will be forced eastward by intruding high pressure. By Tuesday, conditions look to be drier but still on the mild side, with highs in the upper 50s to upper 60s and lows generally in the 40s. One final note- considering that we will be dealing with warm daytime temperatures and mild nights coupled with mild temperatures accompanying rainfall, this should spell the arrival of spring greenup in the next week or so, particularly across northern lower Michigan. This could open the door for any frost / freeze impacts beyond the forecast period to be amplified. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Large area of strong high pressure will currently centered over the Great Lakes region will slowly push eastward into New England over the next 24 hours. Skies will remain clear tonight into Friday...but will begin to increase by Friday night as moisture begins to surge northward well in advance of a developing storm system over the Central Plains. Solid VFR conditions are expected at all Eastern Upper and Northern Lower Michigan TAF sites thru early Friday evening. Light SE winds tonight will strengthen to 15 to 25 kts on Friday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ SHORT TERM...FEF LONG TERM...HAD AVIATION...MLR ####018006282#### FXUS63 KTOP 252311 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 611 PM CDT Thu Apr 25 2024 .KEY MESSAGES... - Several rounds of thunderstorms are expected to move across the area through Sunday. - There is a risk for severe weather each day, with the greatest risk including tornadoes on Saturday. - Multiple rounds of heavy rain could lead to isolated flooding. && .DISCUSSION... Issued at 249 PM CDT Thu Apr 25 2024 19Z water vapor imagery showed an upper trough over the Great Basin with a shortwave lifting through the four corners region. At the surface, low pressure was noted in southeast CO with a warm/stationary front extending through southwest KS and north central OK. Persistent moisture advection over this boundary has maintained the elevated showers and thunderstorms across the forecast area today. The main focus of the forecast is on the potential for severe weather in the coming days. 12Z model consistency is good with an upper low lifting into central NEB Friday morning with a second upper low coming out into the western plains Saturday night and Sunday morning. The warm sector with dewpoints in the lower and middle 60s is expected to lift into northeast KS by Friday afternoon as the initial upper low lifts to the northwest of the forecast area with a dry line developing by the afternoon. This warm moist airmass remains over the area through Saturday night and becomes somewhat modified by Sunday afternoon. Though there is still expected to be some moisture lingering across northeast and east central KS Sunday afternoon. Good environmental shear is progged with a strong wind field forecast through the weekend and the setup for severe storms just doesn't move out of the area until Sunday evening. The MCS this afternoon is expected to continue to propagate southeast along the axis of MUCAPE that extends northeast of the surface warm front. With this having worked over the environment a little, think there may be a break from the deep moist convection into the evening, but the CAMs hint at the redevelopment of showers through the evening. The main point of uncertainty through the evening is where new convection develops. The HRRR has been consistent in thunderstorms developing more over northwest KS within the low level convergence area northeast of the surface low. This would tend to keep storms mainly north of the forecast area through the late evening. However by the early morning hours, PVA with the shortwave should cause development to become more widespread and move east through the morning. These storms look to be mainly elevated with a hail and damaging wind risk, but there does appear to be a narrow axis of surface based instability advecting north through the morning. If storms develop in this axis of surface based instability, the risk for a tornado or two will be higher. By Friday afternoon, forecast soundings from the NAM and RAP show MUCAPE around 3500 J/kg just ahead of the dryline. Good turning in the low level winds are progged to create SRH around 200 m2/s2. More of the models are starting to show a signal for convective initiation along the dryline in northeast KS though there remains some uncertainty given the lack of convection from the HRRR this far south. Supercell thunderstorms would be favored with the potential for very large hail and perhaps a strong tornado into the evening across northeast KS thanks to increasing SRH with the strengthening low level jet. This risk may move east and north of the forecast area by mid evening with shortwave ridging overspreading the area. This should lead to a break in the thunderstorm activity heading into Saturday with the dryline retreating west. The setup for Saturday looks ominous with forecast soundings showing a capped boundary layer with large amounts of CAPE (3000 to 4000 J/kg) within the warm sector east of the dryline. Again good environmental shear would support supercell thunderstorms and as the low level jet increases in the early evening, SRH also increases to around 300 m2/s2. So the concern for Saturday afternoon and evening is for tornadoes, some potentially strong. Shortwave energy is progged to be lifting over the dryline through peak heating and could be the trigger for thunderstorm development. By Sunday, the upper low should be to the north of the forecast area but a diffuse boundary may still be over eastern KS acting as a focus for renewed convection. Models are not as strong with the instability and deep layer shear looks to be a little weaker too. So severe risks may be a little more marginal. Repeated rounds of heavy rainfall could cause some flooding problems before the weekend is over. But confidence in the location of the thunderstorms and where heavy rain develops is a little to low to pinpoint with a watch at this time. Right now the heaviest rainfall is forecast for parts of east central KS, but this could change depending on the short term evolution of the storms. For next week, the pattern becomes a little more zonal with shortwave energy passing through the plains mid-week. With a frontal boundary in the area, there looks to be another chance for showers and thunderstorms Tuesday through Thursday. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 611 PM CDT Thu Apr 25 2024 Scattered showers and thunderstorms will continue this evening and overnight, most likely over the next couple hours and again in the few hours before sunrise. Broken IFR to MVFR ceilings will continue along with this activity, though thunderstorm bases will be more towards 5 kft. Winds remain southeasterly around 15-20 kts overnight, becoming southerly at 20-25 kts once the warm front passes tomorrow morning. Isolated severe thunderstorm development again becomes possible in the last few hours of the period tomorrow. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Wolters AVIATION...Reese ####018005352#### FXAK67 PAJK 252313 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 313 PM AKDT Thu Apr 25 2024 .SHORT TERM...Little in way of changes for Southeast Alaska, as surface ridge continues to keep lighter winds, minimal cloud cover with exception of lower clouds. Anticipate a marine layer to reform in the northeast gulf coast tonight that will likely spread into the coastal area to include: Yakutat, Cross Sound, Perhaps Peril Strait, Western Chichagof Island and Baranof Island, and Western Prince of Wales Island. The clouds and patchy fog under the clouds could start to spreading through Western Icy Strait towards Gustavus by Friday morning. Overall short term dry until perhaps late Friday night as a front starts lifting northwards the southern portion of the panhandle, when chance PoPs start moving in. .LONG TERM...The main theme through the weekend is that an open longwave trough will move into the Gulf, bringing in a 988mb to 998mb surface low, with an escalation in southeasterly winds, waves, and some light rain. The 988mb low demands attention, but is a manifest of the uncertainty found within the deterministic trends. For now, have found a happy medium in the ensembles, with a hedge in the wind field towards the more serious GFS and NAMNEST solution. Confidence is very low that we see a 988mb low develop on the Gulf on Saturday; however, upstream development and model trends will have to be monitored closely as more high resolution models start to capture this feature. Main questions to answer in the coming 24 hours as we watch cyclogenesis is how our waters will either stabilize, or add to the instability, of the air mass, which has implications on how much momentum we can mix down to the surface thus impacting surface wind speeds. If the more robust solutions featuring instability comes to fruition, there is potential to see gale force winds near Dixon and along the western coast of Prince of Wales, along with more elevated and sustained southwest winds Sunday into Monday which increases and prolongs the southwest swell a bit. QPF (quantitative precipitation forecasts) continue to trend downwards but there is some hope if the more aggressive deterministic solutions come to fruition, which could steer some relatively higher IVT into the south. For now, the current forecast utilizes a modern statistical approach, with 48 hour rain totals coming in under 1 inch for most of the region over the weekend into Monday. Tuesday a secondary low forms aloft near Queen Charlotte sound, with northerly flow developing across the Gulf as high pressure builds from the west, likely leading to warming temperatures and clearing skies into Wednesday. With that said, will need to watch the potential for a shallow marine layer keeping some areas a little cooler. Diurnal wind regimes also come to mind. Attention turns to end of next week as another system lifts into the Gulf, with the potential to see a bit more moisture moving into the northern regions. && .AVIATION...Conditions ranging from 3000/5 to CAVU with lower conditions to the south, if you want to call 3000/5 "low". No impactful winds, no wind shear, no problems. One exception: low level marine clouds are expected to move in again tonight and invade the inner channels possibly as far as Gustavus as well as the outer coast. Early to mid morning clearing should produce another day like this afternoon turned out. Go Fly! && .MARINE... The Gulf continues to be docile, with buoys 82,83, and 84 reporting southwest 3 to 4ft swell at 8 to 10 seconds. Expect the swell to increase a touch tonight but concerns remain low through Friday. Threats escalate Saturday into Monday for our mariners operating smaller vessels across southeast Alaskan waters as a band of 25-30 knot southeasterly winds and 7 to 12ft south southwest fresh seas develop, south of Cape Fairweather along our coast. Expect the highest significant wave heights west of Prince of Wales near Dixon Entrance, with southerly 5 to 9ft fresh seas in far southern Clarence Strait exposed to the open waters of Dixon. Mariners operating in Icy Strait will also feel an increase of 15 to 20 knot easterly winds Saturday, with the most concern around Pt. Couverden and Skull Island. Some wording of caution around Saturday for the south. There is potential to see a brief period of gale force winds which would lead to an increase in significant wave heights; however, confidence remains too low to put this threat into the forecast. Will need to continue to monitor the system as it moves off the Aleutian Islands into the Gulf. Tidal variations are relaxing compared to the large swings we saw with the full moon on April 23rd, with Third Quarter on May 1st. Many thanks to the operators in our waters who reported their conditions to WFO Juneau throughout the week. && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...None. MARINE...None. && $$ SHORT TERM...Bezenek LONG TERM....AP AVIATION...Fritsch MARINE...AP Visit us at http://www.weather.gov/Juneau