Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/22/20

National Weather Service Wakefield VA
1039 PM EDT Mon Sep 21 2020 .SYNOPSIS... Strong high pressure will build into the region from the north overnight. This high will stay over the region through midweek before pushing offshore into next weekend. && .NEAR TERM /UNTIL 8 AM TUESDAY MORNING/... As of 940 PM EDT Monday... Latest analysis reveals strong (~1034mb) sfc high pressure centered from New England to the Mid-Atlantic region. Offshore, Hurricane Teddy continues to move nwd NE of Bermuda and has picked up forward speed. The gradient between the surface high and Teddy offshore continues to result in breezy conditions near the immediate coast, but winds are now light/calm inland as the high continues to build in. IR satellite imagery continues to show ocean effect SC hanging on across SE VA/NE NC. Elsewhere, skies are mainly clear. The clouds over SE VA/NE NC are expected to slowly dissipate tonight from NNW to SSE, but will likely hang on for the majority of the night (especially from VA Beach to coastal NE NC). High pressure continues to build over the area tonight, finally allowing the pressure gradient to relax a bit more into midweek. This will also result in excellent radiational cooling conditions, especially over inland areas. Clearing and cold relative to late September. Lows mainly in the upper 30s out along the VA-15 corridor from FVX-LKU...low to mid 40s for most...with mid-upper 50s across coastal SE VA/NE NC. && .SHORT TERM /8 AM TUESDAY MORNING THROUGH THURSDAY/... As of 310 PM EDT Monday... Another pleasant early Fall day across the region...appropriate with the Autumnal Equinox tomorrow. Building upper ridging/sfc high overhead brings a mostly clear/sunny sky with low humidity levels and highs in the low 70s. Not quite as cool Tuesday night with lows in the mid to upper 40s and low 50s along the coast. Sfc high slides offshore and the upper ridge finally starts to break down as remnants of TC Beta start to push across the mid- south region. Resultant return flow will kick start moderating trend with temps bumping back up toward climo normal. Highs Wed in the upper 70s to ~80. Did nudge up sky cover for Wednesday and Thursday, with HRRR Smoke cross section starting to indicate some thin smoke making its way back into the region on building W-NW flow aloft. Remaining dry with early morning lows Wednesday in the low to mid 50s inland to right around 60 degrees at the immediate coast. Dry wx continues on Thursday. Do expect more in the way of clouds, owing to an approaching upper trough...and additional remnant energy from Beta...lifting across the Mid-South region. Some models do start to indicate some very low PoP Thu aftn, but given antecedent dry airmass, will hold PoP off until Thu night at the earliest. Highs Thursday ranging through the 70s, near 80 across NE NC. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 310 PM EDT Sunday... Previously referenced shortwave trough pushes across late Thursday into Friday, allowing for scattered showers across the area (20-35% PoPs) through Friday, with best chances along and south of US-460 given latest information. Weak ridge of high pressure begins to develop by Saturday over the region ahead of a deepening trough to the west. The ridge and trough deepen through the weekend and into Monday as a low pressure system develops over the Great Lakes. The trough and associated cold front moves through the region Monday or Tuesday. The result of this amplified pattern will be an increase in at least isolated/widely scattered prefrontal precipitation chances from Saturday through at least Monday. Highs generally in the upper 70s to around 80F through the extended. Lows Wednesday night will range from the low 50s NW to around 60F near the coast. Lows Thursday through Saturday nights will range from the mid to upper 50s W to the low 60s E. Lows Sunday night will range from the low 60s NW to the upper 60s SE. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... As of 740 PM EDT Monday... VFR conditions across area terminals are expected to continue through the 00z TAF period. SCT-BKN ocean effect SC (~4-5kft AGL) over PHF/ORF/ECG will slowly diminish from NNW to SSE overnight, giving way to SKC conditions at all of the terminals by no later than 12z as high pressure builds toward the local area. Mainly SKC conditions are then expected to prevail through the remainder of the 00z TAF period. Gusty NNE winds (to ~20 kt) at ORF/ECG will turn to the N-NNW and diminish slightly by early Thu AM. Winds are forecast to remain below 10 kt at the other terminals through 12z. Winds turn to the NW during the day on Tue and are expected to be around 10 kt. A few gusts to 15-20 kt cannot be ruled out near the coast (highest gusts on Tue will likely be at SBY). OUTLOOK...Strong high pressure will provide dry/VFR conditions through midweek. && .MARINE... As of 300 PM EDT Monday... The surface high pressure that has been producing the strong NE winds is beginning to weaken over New England this afternoon, allowing winds to come down slightly this afternoon. Winds remain NE but now most sites are reporting around 15 kt with gusts 20-23 kt. The Gale Warning for coastal waters off Currituck County was allowed to expire earlier this afternoon. Winds south of Cape Henry are 20-25 kt with a few gusts up to 30 kt. Winds across area coastal waters will continue to decrease into the evening. The surface high pressure over New England will slide southwest into the Mid-Atlantic tonight and into Tuesday. Winds will turn north overnight and into Tuesday morning and be 15-20 kt. Therefore, SCAs for the Bay and Currituck Sound have been extended through 15z/11am Tuesday, and remain at 09z/5am Tuesday for the lower James, and 22z/6pm today for the remaining rivers. The combination of onshore flow and Hurricane Teddy will result in seas remaining 8-12ft through tonight and subsiding to 6-10ft Tuesday, with 5-7ft waves in the mouth of the Bay today subsiding to 3-4ft Tuesday. SCAs for the ocean N of the VA/NC border have been extended through 11z/7am Wednesday, and remain 22z/6pm Tuesday for the mouth of the Bay. Hurricane Teddy is forecast to make landfall in Nova Scotia early Wednesday. The wind will become WNW 10-15kt across the bay and 15-20 kt across the ocean. Seas are expected to subside once the hurricane makes landfall and the wind becomes offshore. High pressure then slides offshore later in the week with the wind becoming southerly. Seas are expected to subside to ~2ft by the end of the week. && .HYDROLOGY... As of 740 PM EDT Monday... Flood Warnings remain in effect for the Nottoway River near Sebrell and the Blackwater River near Franklin. Flood Warnings will likely will remain in effect for at least the next day or two at these sites. See FLWAKQ/FLSAKQ and for more site-specific information. && .TIDES/COASTAL FLOODING... As of 955 PM EDT Monday... Have extended the Coastal Flood Advisory for the northern Neck through the upcoming high tide cycle overnight/early Tue AM for minor flooding at Lewisetta. Allowed the Bay side of the MD eastern shore to expire as water levels are expected to fall just shy of minor flood early Tue AM. Also raised a new Coastal Flood Advisory for Currituck/Va Beach/Norfolk/Chesapeake through the upcoming high tide cycle. If departures are slow to fall on Tue, additional advisories may be needed into early aftn but will allow next shift to evaluate how the departures verify w/ the upcoming tide before extending the headlines. The flood tide from this aftn was higher/stronger than forecast by CBOFs (was almost 2.0 kt) so we will see how that potentially affects the water levels in the Bay during the next 12 hrs (possibly keeping them higher than model forecasts). The ebb tide right now at the mouth of the Chesapeake Bay is averaging 1 to 1.5 kt so some water will get out and am not expecting a major increase in anomalies over the Bay, rather that they will not fall as rapidly as the models from earlier today were forecasting. This could have implications on the high tides Tue, with some potential for minor flooding around the time of high tide at some locations with additional Coastal Flood Advisories being needed. Tidal departures are expected to eventually diminish by Wed as the flow becomes a bit stronger offshore, and swell from Teddy subsides/moves N of the region. Swells enhanced by Hurricane Teddy (well offshore), with periods of ~15 seconds, and very large waves of 10-12 feet+ will make for very dangerous conditions at the Atlantic Beaches through Tue. In addition, there is dune/beach erosion potential, especially for more vulnerable locations with the high tide cycle late tonight before conditions improve for midweek. Beach Hazards Statements/High Rip Current Risk continue early this week. A High Surf Advisory remains in effect for the Atlantic coast as waves in the surf zone range from 8-10ft N to 10-12ft S. && .EQUIPMENT... As of 940 PM EDT Monday... KAKQ radar remains offline due to an equipment issue. More info will be passed along as it becomes available. See FTMAKQ for more information. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...High Surf Advisory until 2 PM EDT Tuesday for MDZ025. NC...High Surf Advisory until 5 PM EDT Tuesday for NCZ102. Coastal Flood Advisory until 6 AM EDT Tuesday for NCZ102. VA...High Surf Advisory until 5 PM EDT Tuesday for VAZ098. Coastal Flood Advisory until 6 AM EDT Tuesday for VAZ095-097- 098. High Surf Advisory until 2 PM EDT Tuesday for VAZ099-100. Coastal Flood Advisory until 8 AM EDT Tuesday for VAZ075-077- 078. MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ634. Small Craft Advisory until 11 AM EDT Tuesday for ANZ630>633. Small Craft Advisory until 6 AM EDT Tuesday for ANZ638. Small Craft Advisory until 7 AM EDT Wednesday for ANZ650-652- 654-656-658. && $$ SYNOPSIS...MAM NEAR TERM...ERI/MAM SHORT TERM...MAM/RHR LONG TERM...MAM AVIATION...ERI/MAM MARINE...AJZ/CP HYDROLOGY... TIDES/COASTAL FLOODING... EQUIPMENT...
Area Forecast Discussion
National Weather Service La Crosse WI
1047 PM CDT Mon Sep 21 2020 .UPDATE... Issued at 633 PM CDT Mon Sep 21 2020 Currently monitoring scattered showers and a few storms across north central WI. These were along some 850mb moisture transport and warm air advection. With better moisture transport waning, expecting these showers and storms to diminish this evening. Will then be monitoring a decent mid-level shortwave trough pushing across the Dakota as of this update. This wave will be pushing east into our area after midnight tonight with some mid-level frontogenesis noted by the RAP model. This is expected to fuel isolated showers and perhaps a rumble of thunder or two. So, have added the mention of a slight chance of storms after midnight which is a change from this afternoon`s thinking. && .SHORT TERM...(This evening through Tuesday) Issued at 143 PM CDT Mon Sep 21 2020 A bit of upper level energy will spin out of the Northern Plains tonight, slipping across WI Tue morning. The shortwave will push a sfc front across the region, taking on a west-east orientation. With some weak 850 mb transport into the front, most meso models suggest there will be enough saturation/lift for isold/scattered showers - perhaps even a rumble of thunder with elevated instability (evidenced in RAP bufkit soundings). For now, enough support to include small rain chances tonight (will hold off on thunder for now). Amount looks minimal, mostly coming out of a mid deck with some drier air under cloud bases to work on (maybe just virga in spots). .LONG TERM...(Tuesday night through Monday) Issued at 143 PM CDT Mon Sep 21 2020 A weak low pressure system and associated mid-level short-wave trough looks to move into the region Wednesday night. Although low, precipitation chances return with the system and last through Thursday. There is some uncertainty with how far south these rain showers develop, but currently expecting them to remain mainly north of I-90 with better chances even further north of I-94. With a some instability, isolated storms are possible, but the chances are small. Dry weather settles in to end the weekend as upper-level ridging builds over the region. Afternoon temperatures in the 70s to low 80s are expected. A more substantial and deeper extending trough is anticipated to drop through the region over the weekend. Widespread rain chances last from Saturday afternoon into Sunday. Will keep an eye on storm chances as there is a decent amount of shear available, but there is a limited amount of instability. Storm chances would depend on where the precipitation develops in relation to the surface front. Low-level shear looks better ahead of the front along with better instability, whereas deep-layer shear is better along and behind the front. After this system passes, temperatures cool down into the 60s and low 70s to start off the new week. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1045 PM CDT Mon Sep 21 2020 VFR conditions through the TAF period. Pre-frontal showers continue to linger just south of La Crosse and cloud trends show some patchy mid clouds across southern MN and somewhat better development south of the TAF sites. A subtle shortwave trough is pushing across MN into northern WI, but is not expected to be strong enough to push the surface front south. Forecast soundings and some of the short range indications bubble up a few showers and with elevated instability around 350 to 400 J/kg around 14K ft. With this area becoming saturated, could see a few rumbles of thunder. Due to the isolated nature of the showers and storms, will include an hour or two of vsch at KLSE around 08Z, otherwise sct-bkn mid clouds fl100-150. Southeast to southwest winds 6 to 12kts. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ UPDATE...DAS SHORT TERM...Rieck LONG TERM...Peters AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Bismarck ND
931 PM CDT Mon Sep 21 2020 .UPDATE... Issued at 930 PM CDT Mon Sep 21 2020 Skies are clear across the region and winds are generally less than 10 mph. Current forecast looks good. UPDATE Issued at 610 PM CDT Mon Sep 21 2020 With surface high pressure dominating the weather regime, we see no need to change the forecast tonight. Clear or mostly clear skies and light southwest to west winds. && .SHORT TERM...(This afternoon through Tuesday) Issued at 220 PM CDT Mon Sep 21 2020 No significant forecast issues in the short term period. Currently, upper level low continues to push east across southern Canada, with quasi-zonal flow aloft over the Northern Plains. Decent pressure gradient north and east of sfc high pressure positioned over southwest North Dakota contributing to gusty west/northwest winds across my north and east this afternoon. Winds will taper off mid to late afternoon as the sfc high continues to build east across the state. Southerly return flow develops from west to east tonight as high pressure drifts to the east and low pressure develops off to our west. A dry boundary layer and a clear sky will result in good radiational cooling with overnight lows in the 40s to low 50s. Tuesday will potentially be one of the warmer days of the week as WAA develops northward across western and central ND along to east of a sfc trough. HRRR does indicate the return of smoke into the region late tonight through the day tomorrow, so daytime highs may be impacted. For now kept with a model blend as perhaps only western and southern areas look to be impacted by the smoke and will warrant a reduction in temperatures. Will let the mid shift relook things. .LONG TERM...(Tuesday night through Monday) Issued at 220 PM CDT Mon Sep 21 2020 An embedded mid level wave moving across the region Tuesday night through Wednesday morning will combine with decent 0-6km shear and elevated instability to trigger off a few showers and isolated thunderstorm, mainly north of I94 and likely around to north of Highway 2 along a weak cold FROPA. Confidence remains low we will see any severe weather, but wouldn`t be surprised a storm or two could throw out a strong wind gust or some small hail given the wave and shear advertised. In the wake of the front during the day Wednesday, cooler temperatures in the 60s and 70s and a shift to northerly winds are forecast ahead of a sfc ridge. Winds transition to southerly for Thursday as high pressure moves east and low pressure develops over eastern Montana. Temperatures will rebound, perhaps robustly across the far west where a few models depict a decent thermal ridge forming. Another mid level wave will then push the sfc trough/cold front southeast through the state Thu/Thu night though with a dry boundary layer wouldn`t expect much moisture reaching the surface. An upper level trough is still advertised to form across the region for the beginning of the weekend, then a broad northwest flow pattern Sunday/Monday. This pattern will result in cooler temperatures and chances for showers. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 610 PM CDT Mon Sep 21 2020 VFR expected. High pressure centered near Aberdeen this evening will drift southeast tonight. Clear skies are expected with light southwest to west winds. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...NH LONG TERM...NH AVIATION...WAA
Area Forecast Discussion...CORRECTED
National Weather Service Boise ID
832 PM MDT Mon Sep 21 2020 .DISCUSSION...Today was warmer than forecast with less smoke and better mixing than expected. But smoke was increasing from the southwest late today and latest HRRR suggests it will continue to increase overnight and Tuesday morning. That together with an incoming weak upper trough will lower temps on Tuesday. Slight chance of showers in northern mountains midday Tuesday otherwise dry. Stronger trough and surface cold front will bring more significant cooling Thursday and Friday. Current forecast is on track. && .AVIATION...VFR with areas of smoke. Mid to high clouds increasing Tuesday morning. Isolated rain showers for eastern Oregon Tue/11Z through Tue/16Z. Surface winds: variable 10 kt or less, becoming west to northwest 5-15 kt Tuesday afternoon. Winds aloft near 10k feet MSL: southwest 15 to 25 kt. && .PREV DISCUSSION... SHORT TERM...Tonight through Wednesday night...Clouds will increase overnight as a weak trough pushes into the interior NW. East-central Oregon and the west-central Idaho mountains could see a sprinkle/shower early Tuesday morning as the wave passes to the north. Tuesday will be dry and a few degrees cooler. Southwest flow returns on Wednesday bringing dry and breezy conditions along with warmer temperatures. Winds will become gusty in the afternoon across southeast Oregon and mountains of southwest Idaho as flow aloft mixes to the surface. Clouds will increase Wednesday night and showers are possible across northern zones ahead of a trough pushing into the Pacific NW. LONG TERM...Thursday through Monday...A cold frontal boundary will make its way across the region Thursday bringing cooler than normal temperatures and increased showers, mostly for our northern areas. The associated trough axis will push through the area by Saturday afternoon making way for an upper level ridge to build offshore. Northwest flow aloft and drier conditions will prevail for the remainder of the period. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ DISCUSSION...LC AVIATION.....SH PREV SHORT TERM...DG PREV LONG TERM....JC
Area Forecast Discussion
National Weather Service Burlington VT
731 PM EDT Mon Sep 21 2020 .SYNOPSIS... Expect dry conditions and the gradual warming trend to continue right through midweek as high pressure remains over the region. Low temperatures will not be as cold as the previous few night, but frost will still be possible tonight, especially away from Lake Champlain. Daytime highs are expected to reach seasonal normals by Wednesday. It appears our next chance of rain will come Thursday night as a cold front moves into the region. Rainfall amounts however looks to be less than a quarter inch. Above normal temperatures are expected for the weekend with another chance of precipitation late in the day on Sunday. && .NEAR TERM /THROUGH TUESDAY NIGHT/... As of 731 PM EDT Monday...Quiet and clear and cold overnight conditions expected with some thin smoke aloft drifting through the region. Latest HRRR smoke model shows thicker smoke aloft currently over the Great Lakes will move into the North Country tomorrow, so while no restrictions in surface visibility is expected, added in haze to the forecast since the sky will be cloudless, but not clear by any means in the afternoon. Previous Discussion...Still looking at rather quiet weather through Tuesday night with high pressure at the surface and aloft over the region. The warming trend that began today will continue right through Tuesday night. Lows tonight will not be as cold as the last few night with lows generally in the 30s, but some upper 20s over parts of the northern Adirondacks and Northeast Kingdom of Vermont. Expecting frost at most locations, except in and around Lake Champlain. Will not be issuing a Frost Advisory for the areas that have not seen a killing frost or freeze, but will carry the mention of frost in the forecast. We are starting to pick up some high level smoke from the western United States fires, but smoke is expected to remain high enough to have no impact on air quality. Should see the impacts of the smoke mainly at sunset and sunrise. Warming trend continues on Tuesday with highs getting into the 60s across the entire area. One item of note will be the pressure gradient strengthening across the area with Hurricane Teddy moving north toward the Canadian Maritimes. This will result in more wind than today with areas across Vermont experiencing northwest winds in the 10 to 15 mph with gusts in the 20 mph range. Slightly less wind is expected for northern New York. No precipitation is expected on Tuesday and Tuesday night for that matter. Tuesday night should be frost free with lows generally in the 40s. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 257 PM EDT Monday...Relatively quiet period with mainly increasing clouds on Wednesday as a weak shortwave passes through NW flow off. Not expecting any measurable precipitation, but with moisture between 5000-10000 feet, a few sprinkles may be possible across the higher terrain. Otherwise, it should be a mostly dry day with near seasonable temperatures in the mid to upper 60s and overnight lows in the upper 40s to low 50s. While clouds may obscure viewing, smoke from the western wildfires will once again advect back into the region, but similar to last week this smoke will remain high in the atmosphere with no impacts expected locally. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 257 PM EDT Monday...Little changes made to the forecast with best chances for a widespread, wetting rain to occur towards the end of the weekend into early next week. Upper level flow will turn out of the west behind the weak shortwave on Wednesday, with another impulse moving through 500mb flow late Thursday into Friday morning. Plume of moisture extending from the Great Lakes into New England should provide enough for some light rain showers across the area. The best chance for any measurable rainfall will be for locations near the international border where 0.10-0.25" is possible. After this, subtropical high becomes well established across the eastern US with dry weather expected Friday, Saturday and most of Sunday. Sfc-850mb flow turns out of the southwest Saturday into Sunday as digging upper level trough organizes across central US. Saturday will feature above normal temperatures in the mid to upper 70s with fairly steady south winds, 10 to 15 mph. Low pressure will move eastward Sunday night, and along with a pattern change for the beginning of next week. Precipitation chances increase on Monday with consistent signals for a fairly widespread precipitation event. Large upper level trough remains across eastern US with continued chances for rain through mid week. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Through 00Z Wednesday...VFR conditions will prevail through the period. Could see a brief period of IFR at KSLK or KMPV, but confidence is too low and based on drier afternoon dewpoints and slightly warmer overnight temperatures, think coverage will be much less than last night. IF it does happen, it will be between 06-11Z. Otherwise, clear skies tonight will be replaced by a layer of smoke aloft, but no clouds expected tomorrow. Light winds overnight shift to the north tomorrow at 5-10kts. Outlook... Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: VFR. Slight chance SHRA. Friday: VFR. NO SIG WX. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Evenson NEAR TERM...Evenson/Lahiff SHORT TERM...LaRocca LONG TERM...LaRocca AVIATION...Lahiff
Area Forecast Discussion...Updated
National Weather Service Billings MT
845 PM MDT Mon Sep 21 2020 .UPDATE... Quiet weather continues to dominate tonight, so no update needed. Looking at the latest run of the HRRR Smoke, it still looks like the smoke will continue to move back into the area with the riding, but the surface impacts still look much less than the area saw last week. Reimer && .DISCUSSION... Tonight through Wednesday night... Upper ridging will prevail over the area into Tuesday, before a weak late day cold front moves through during the late afternoon and evening. Smoke from wildfires across the West will move back into the area on Tuesday as well. The front may bring a few isolated light showers to the higher terrain and eastern areas during the evening. A rumble of thunder is possible over the mountains as well. Ahead of the front, highs will reach the 80s with afternoon RH into the teens, although winds are not expected to be overall very strong. A few gusts into the 20s mph are possible with the frontal passage in the evening. Cooler conditions are expected in the wake of the front on Wednesday with ridging building back over the region. Highs in the upper 70s to around 80 degrees can be expected. STP Thursday through Monday... Thursday continues to look like a serious fire weather day. Fast WSW flow aloft with a wave in the flow, will push a cold front SE into the area during the afternoon. Winds will become gusty ahead of the front and will remain gusty behind it, with gusts to at least 30 mph W of KBIL. Winds will be gusty in the E as well, but not as strong as in the W. Temperatures will reach the mid to upper 80s with the NBM showing a possible record temp of 89 in KSHR. Humidities will be mainly in the teens across the area. Will add a headline in the FWF discussion for Thursday. It will be much cooler behind the front, and an atmospheric river was progged to be over the area through Friday. Models showed either zonal flow or a weak upper trough over the area on Friday. Showers will move into the area behind the front Thu. night and continue through Fri. night. Lows in the mountains will be in the 20s Fri. night which will support snow showers. Model clusters showed increased pattern uncertainty for Saturday with solutions ranging from a trough over the area to WNW flow. Saturday looked like the windiest day of the period, with the EC ensembles showing gusts to around 40 mph across the area. The NBM supported the gusty winds. Scattered showers will continue over the area with seasonable temps. Large high pressure ridge will dominate the West for the rest of the period. There was uncertainty in the ridge position in the clusters. EC ensembles showed possible gusty winds during this period. At this point, temps and RH`s did not look hazardous for fire weather. Arthur && .AVIATION... VFR conditions will prevail through the period. Winds will increase again Tuesday afternoon ahead of a cold front. Arthur && .PRELIMINARY POINT TEMP/POPS... Tue Wed Thu Fri Sat Sun Mon ----------------------------------------------------------- BIL 048/085 050/080 054/086 049/067 045/069 049/075 052/075 01/K 10/B 00/B 23/W 42/T 21/U 11/B LVM 043/084 043/080 049/080 043/064 039/067 045/073 046/076 01/K 10/B 01/B 34/T 43/T 11/B 11/B HDN 045/086 047/080 050/089 047/069 043/068 045/075 048/075 00/K 20/U 00/B 23/W 42/T 21/U 11/B MLS 047/084 051/078 053/088 049/070 045/068 048/073 048/072 00/K 20/B 00/B 22/W 32/T 21/B 11/B 4BQ 047/087 051/080 052/090 048/071 044/068 046/073 047/072 00/K 20/U 00/B 12/W 43/T 22/W 11/B BHK 048/085 049/077 049/085 048/068 043/066 045/070 045/068 00/K 10/B 00/B 11/B 42/T 21/B 21/N SHR 046/089 046/081 049/088 044/070 039/068 042/074 045/073 01/K 20/U 00/B 14/T 54/T 22/W 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service State College PA
1037 PM EDT Mon Sep 21 2020 .SYNOPSIS... High pressure over Pennsylvania will shift south of the state during midweek. Increasing meridional upper level flow is expected by next weekend, as a deepening trough forms over the plains and an upper ridge builds off the east coast. At the surface, expect a slow moving cold front to approach the state from the west by late next weekend. && .NEAR TERM /UNTIL 8 AM TUESDAY MORNING/... Have only adjusted temps and dewpoints slightly to match up with current obs/trends. As with the last few nights, many places will flirt with freezing, and pretty much everyone outside the urban of areas will have frost. Will hold the advy in place with no changes. Prev... Temps and dewpoints nearly identical to 24hrs ago. Fcst mins nearly identical to last night`s as well, and see no reasons to change at this point. Prev... Tonight will be the last in a string of chilly nights with frost concerns. Aside from Clearfield, Srn Center and Sullivan Counties, whose growing seasons were ended this morning, Frost Advisories will be hoisted in most of the same areas as last night. Mins will be within a degree or two of Monday morning mins. && .SHORT TERM /8 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... Center of surface high will drifts south of PA Tuesday, allowing a warmer push of air into the region on westerly flow. Abundant sunshine, dry boundary layer will allow readings to reach back to near seasonal average after 3 days of below normal highs. One caveat...latest HRRR smoke model indicates smoke from western fires will reach northwest PA Tuesday afternoon ahead of shortwave crossing the Grt Lks, so maxes remain below guidance over our northwest counties. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... The forecast for the extended/long term changes very little with this evening update. The next real chance for rain is not until late in the weekend. Previous disco tells the story very well. Prev... Mid level shortwave is progged to dive southeast across the region Tuesday night. This moisture-starved feature is likely to produce nothing more than a bit of mid/high level cloudiness. However, a slight uptick on low level moisture, combined with a light westerly breeze, should result in a milder night than those recently with lows mostly in the 40s. Shortwave and associated plume of upper level smoke should exit the area by Wednesday. Large scale subsidence behind this feature should translate to another mainly sunny day. Mixing down ensemble mean 850mb temperatures of 12C yields expected highs from the low 70s over the highest terrain of the Alleghenies, to the low 80s in the Susq Valley. Still looking very dry in the long term at least until next weekend. Multiple waves moving along the US/Canadian border will be starved of moisture. The only one of note would be passing us Thursday night or Friday but that will most likely just bring us some clouds. The GFS is wetter, making a few hundreths here and there, versus the EC with this upper trough passage. It does look like smoke aloft from the western forest fires will return to the region toward the middle of the week again giving us hazy skies. Due to this, I lowered max temps by a few degrees Wednesday and Thursday. A more robust trough looks to move into the region later next weekend and early next week, which may bring a better chance for showers. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... VFR conds will continue tonight and tomorrow. Winds will be light to calm overnight. Expect W to NW winds of 5 to 10 kts with gusts of 15 to 20 kts on Tue. Outlook... Tue-Wed...VFR conditions. Thu-Fri...AM valley fog poss, then generally VFR Sat...Generally VFR, with rain possible Sat night && .CLIMATE... The record low temperature of 33 (1956) was tied at Williamsport this (Monday) morning. Cold temperatures were noted across the region the last 3 nights. Another cold night is in store for the region tonight. With multiple reporting stations coming in below 32 degrees in Clearfield, southern Centre and Sullivan counties, the growing season has now ended for these zones. && .CTP WATCHES/WARNINGS/ADVISORIES... Frost Advisory from 2 AM to 9 AM EDT Tuesday for PAZ024>028- 033>036-045-046-049>053-056>058-063>065. && $$ SYNOPSIS...DeVoir NEAR TERM...DeVoir/Dangelo SHORT TERM...DeVoir LONG TERM...Dangelo/Travis AVIATION...DeVoir/Colbert CLIMATE...
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
636 PM EDT Mon Sep 21 2020 .AVIATION... Forecast remains on track for tonight and Tuesday. Winds will quickly diminish to 5 knots or less after 00z. VFR conditions through the taf period as large area of high pressure continues to dominate the across the region. Winds will veer to more southwest by Tuesday and increase to near 10 knots. An elevated front will provide some mid/high clouds around 15kft Tuesday as the high keeps the lower levels clear. .DTW THRESHOLD PROBABILITIES... * None. && .PREV DISCUSSION... Issued at 332 PM EDT Mon Sep 21 2020 DISCUSSION... Dominant surface high pressure elongated through the Northeast combined with a mid-level anticylone over the lower Ohio Valley will maintain dry conditions for the remainder of today. 21.12 KDTX RAOB measured a robust subsidence inversion near 750 mb which has now lowered to around 800 mb. Light southeasterly flow has promoted slight warm advection nudging high temperatures just above the 70F mark for the first time since last Wednesday. Afternoon skies become more opaque this evening from northwest to southeast with the next round of Western wildfire smoke filtering in. Weak upper level flow within a controlling ridge axis will transition tonight as the feature pivots downstream toward the northwestern extent of Hurricane Teddy, taking aim at Nova Scotia. Winds will become nearly calm and re-orient southwesterly overnight in the return flow regime. Outgoing longwave radiation will be largely uninhibited by cloud-free skies allowing overnight lows to settle a few degrees below climatological normals (mid-upper 40s) by daybreak. Made slight adjustments to account for meager warming influence of diffuse smoke aloft. An approaching shortwave trough dampens slightly on Tuesday with diminishing geostrophic winds as it moves zonally across the northern Great Lakes. This feature will generate some mid-level ascent/moisture advection capable of producing periodic altostratus cloud. Given the dryness of the lower levels, precipitation is not expected, even as PWATs trend upward to near 0.75 inches. The column will also moderate with 850 mb temperatures rising 3-4C bringing about a return to normal highs/lows. HRRR Vertically Integrated Smoke suggests upstream trajectories will advect additional smoke across all of Lower Michigan, thus bumped sky cover up a bit to reflect this through the overnight hours. Confluent flow aloft on Wednesday with the better jet branch displaced to the north and east yields another dry day. It will be the warmest day of the week as highs flirt with 80F near the Tri- Cities and Metro areas. Dewpoints will be noticeably higher, crossing the 60F threshold by midday as a narrow plume of moisture spills southeast from Wisconsin. Expect some resultant marginal MLCAPE, but given the moisture void above the boundary layer, only impact will be some fair-weather diurnal cumulus and a few gusts mixing down near 20 mph. What remains of the upper low from Tropical Depression Beta will breakdown over the Mississippi Valley on Thursday. This will clash with some ridge running shortwaves dropping in from the northwest, although mid-range guidance is not particularly well phased. Split- flow over Southeast Michigan will limit the kinematics therefore left low/dry PoPs through the end of the workweek. Next opportunity for precipitation should arrive this weekend. The ECMWF is a bit faster than the GFS with the arrival of a broad longwave trough driving height falls and PVA into the Great Lakes late Saturday into Sunday. The resident warm sector will be displaced by a cold front extending up into central Canada with plenty of FGEN and available moisture. Broad coverage of showers will accompany the FROPA. Once it clears, temperatures will trend cooler into early next week with additional rain chances on-deck from a seasonably strong low pressure system Monday night. MARINE... High pressure along the Appalachians will reposition over the Ohio Valley during the week continuing favorable boating conditions through the period. A weak cold front will settle across northern Lake Huron late Tuesday and remain near stationary through the week. & && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....RBP DISCUSSION...KK MARINE.......DRC You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Green Bay WI
1039 PM CDT Mon Sep 21 2020 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Tuesday Issued at 244 PM CDT Mon Sep 21 2020 Satellite imagery at 19Z showed a line of mid clouds stretching from northwest Iowa, to southeast MN, and into northeast WI. There have been scattered, weak returns on radar associated with these clouds all day, but have not seen any signs of much, if anything, reaching the ground across the GRB forecast area. There was a lone lightning pulse in Vilas County around 1745Z. More recently, some weaker thunderstorms have formed back to the west near Minneapolis which coincides with a weaker band of CAPE and mid- level lapse rates around 7.5 C/km. Given the current trends along with some added support from a weak upper jet streak, expect this band of clouds and occasional showers to continue this evening and overnight, while also gradually shifting southward. Models forecast CAPE up to 500 J/kg and mid- level lapse rates up to 8.0 C/km, so will maintain a slight chance of thunder as well. Expect overall coverage and intensity to be low given the lack of moisture. Some patchy fog is possible across north- central WI early Tuesday morning, meanwhile any lingering showers across east- central WI will come to an end. The rest of the day looks quiet and perhaps less hazy, as the HRRR smoke fields indicate the upper level smoke pushes southeast tomorrow. Temperatures will remain mild for early fall, with lows tonight in the lower 50s, and highs for the first day of autumn in the lower 70s along the lakeshore, and in the mid to upper 70s everywhere else. .LONG TERM...Tuesday Night Through Monday Issued at 244 PM CDT Mon Sep 21 2020 Forecast concerns generally revolve around precip chances on Thursday and also over the weekend. The details keep evolving during these two periods, as models struggle to maintain continuity. Precip chances may be slowing down a tad on Thursday (and also increasing) while speeding up slightly over the weekend. Have a slight preference for the ecmwf. Tuesday night through Wednesday night...The weak front will be lifting north on Tuesday night into Wednesday as winds aloft back from the west to the southwest. Though some clouds may linger along the front, mainly over northern WI, dry and mild conditions look to continue during these periods. Highs on Wednesday will remain in the middle to upper 70s. The next shortwave will approach north- central WI by late Wednesday night. Clouds will therefore be increasing through the night, with most precip chances arriving after midnight. Due to the slower timing, most thunder chances may not arrive until very late in the night into Thursday morning. Rest of the forecast...The shortwave energy will then proceed to move across the region on Thursday, but also weaken in the process. The highest chance of precip will therefore occur north and west of the Fox Valley where a few thunderstorms will be possible. Most models show precip amounts will remain on the lighter side, though still some room for beefier amounts of precip if the stronger solution works out. The clouds and precip will likely keep temps cooler on Thursday. The chance of precip will come to an end by Thursday evening. Then another surge of warm air will occur on Friday into Saturday. Temps may approach 80 degrees at some of the warmer locations. As a digging trough pushes a cold front into the region, the chances of showers and storms will increase through the day on Saturday. Models are showing a stronger system than 24 hours ago, which could lead to the possibility of heavy precip and thunderstorms. Then conditions turn cooler and showery for Sunday. && .AVIATION...for 06Z TAF Issuance Issued at 1034 PM CDT Mon Sep 21 2020 Light precipitation falling out of mid clouds (though with some lightning) pushed across the north and was now sliding through the southern part of the forecast area. Another shortwave will arrive from the west overnight, and with steep mid-level lapse rates in place it is possible additional light showers and even a few additional thunderstorms could develop. Low-levels remain dry, so bases should be relatively high. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....KLJ LONG TERM......MPC AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
744 PM EDT Mon Sep 21 2020 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 306 PM EDT Mon Sep 21 2020 - Warm and Dry Through Saturday - Wet and cooler Sunday through Wednesday - Smoke will hang around into mid week && .DISCUSSION...(This evening through next Monday) Issued at 306 PM EDT Mon Sep 21 2020 -- Warm and Dry Through Saturday-- The official start of Fall is tomorrow at 931 am. The rest of this week into the weekend is likely to be warmer than normal. The average high temperature at Grand Rapids from the 22nd through the 26th is 69 degrees. We are forecasting highs in the range of 75 to 78 during that time period. The normal low averages 48 degrees, which is what our forecast is for Tuesday morning, but the rest of the week, lows are forecast closer to 56 degree. Both the high and low temperatures are forecast between 5 and 10 degrees above normal. We can thank the polar jet for being north of the Canadian border for this. Also we have upper level ridging for the most part through this period. We do actually have three shortwaves come through this area during that time but the first two (tonight and Wednesday) are on the northern stream and the 1000 to 850 mb flow stays from the southwest even through the upper level winds do briefly shift to the northwest behind each of these shortwaves. That means we continue to get feed of warm dry air through the week. By Saturday we have the the first of the three Pacific shortwaves that came from the area of eastern Russia coming into the Great Lakes. That really increases the upper heights over us and results in strong warm advection. I could see highs into the 80s if this plays out that way. Still it will be to dry for rain, even then. -- Wet and cooler Sunday through Wednesday-- By Sunday we start to see the impact of the second Pacific shortwave coming toward us. Since there is a trailing wave digging into the back of the Pacific trough near the dateline we get strong rossby wave breaking over the Great Lakes as this is happening. By Monday afternoon both the GFS and ECMWF and their ensemble members. A deep upper trough with a closed upper low develops near this area. This time we are deeply inside of the cyclonic side of the polar jet. That will result in enough low to mid level instability for lake effect showers, water spouts and other related phenomena. It will also turn much colder. I would expect area wide highs in the 50s at best by Tuesday. The details of how this plays out at the surface for rain is still being resolved by the models but the ensembles of the GFS (20) and the ECMWF (50) all show precipitation in that time frame. At this point it would seem later Sunday into Tuesday is when most of the precipitation should occur. The ECMWF ensemble mean area wide precipitation in on the order of an inch for that time period with the greatest amounts, near 1.3 inches, being west of US-131 (lake effect enhancement). -- Smoke will hang around into mid week-- The smoke is back and more than likely will remain around most of this week since the overall mid level flow is from the west. Until that changes (maybe by Saturday) we will continue to see that smoke layer. From the RAP model smoke cross sections, it seems most of it is between 5,000 ft and 20,000 ft. The greatest smoke density is near 10,000 ft. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 744 PM EDT Mon Sep 21 2020 VFR continuing with clouds above 12K ft and some smoke above 7K feet. Light southeast sfc winds tonight becoming southwest around 10 kts by mid morning Tuesday. && .MARINE... Issued at 306 PM EDT Mon Sep 21 2020 Our wind/wave event north of Whitehall is playing out largely as forecast. Ludington`s buoy has waves around 5 feet as of a few minutes ago. Most of the marine buoys and near shore mesonet have wind gusts in the 20 to 25 knot range. As the northern stream system passes north of here the pressure gradient decreases. So, the winds and waves will subside. We should be able to allow the headlines to expire on time (8 pm). The next event seems to be associated with the system coming into the area on Saturday. Once in the area we may need marine headlines into Tuesday or even Wednesday. If we get that rossby wave breaking event to really happen we may need gales at some point during that time. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement until 8 PM EDT this evening for MIZ037- 043. LM...Small Craft Advisory until 8 PM EDT this evening for LMZ848-849. && $$ SYNOPSIS...WDM DISCUSSION...WDM AVIATION...Meade MARINE...WDM
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
623 PM CDT Mon Sep 21 2020 .SHORT TERM... 133 PM CDT Through Tuesday night... With a surface high pressure system position to our east, low pressure system toward the north, and weak low to upper-level tropospheric flow, persistence is the way to go for the forecast through at least Wednesday. Lows tonight and highs tomorrow will be a few degrees more than last night/today, and surface winds will remain relatively light out of the south to southwest. Experimental HRRR vertical integrated smoke indicates upper-level smoke will continue to stream overhead through the foreseeable future, so will also maintain wording for partial sky cover through at least Wednesday morning. Borchardt && .LONG TERM... 253 PM CDT Wednesday through Monday... The generally tranquil and mild pattern will finally come to an end this weekend with a frontal passage Saturday evening and night. A cool and unsettled pattern could then unfold next work week. Wednesday will have a combination of increased high clouds and likely lingering smoke aloft from western wildfires, but as 925 mb temps rise into the upper teens Celsius, dry air mass should still be conducive to warming into the upper 70s to around 80 for highs. Thursday afternoon should also be primarily dry with similar to maybe a hair cooler temperatures. There will be a fairly complex pattern aloft with a short-wave trough rounding western and central CONUS ridging. The ECMWF shears out the wave less and even closes off 500 mb low for a time. If this general idea verifies, some isolated to scattered showers may be possible in the northwest CWA later in the afternoon into the evening. For now, maintained dry NBM forecast. The Thursday PM-night short-wave could then serve to effectively block off moisture trajectories from tropical remnants to get involved with Saturday evening and night`s frontal passage. At this vantage point, Friday through Saturday afternoon appears dry and mild/warm with highs around 80F on Friday and low to possibly mid 80s on Saturday in breezy southwest flow immediately ahead of the front. As mentioned, the moisture return on Saturday will be lacking, so we might eek out a ribbon of dew points a couple degrees either side of 60F. In addition, while there is time for change in this, the current timing of large scale forcing from stout digging trough and surface cold front is diurnally unfavorable, happening primarily after sunset Saturday evening. There will be enough forcing for at least scattered showers with the front, but lacking instability and unfavorable timing should limit thunder coverage to isolated/slight chance. There`s pretty decent agreement for this far out that Sunday will be between waves behind the cold front, so should be mostly dry, and therefore collaborated PoPs downward to mainly slight chance. Temperatures will step down to the lower to mid 70s, so still could turn out a decent day. Medium-long range operational and ensemble guidance is in good agreement in an impressive long-wave trough setting up shop over the eastern CONUS (including Midwest) next work week. Details of how we get there are a bit muddled to start the work week. Impressive short-wave that will carve out this trough could spur deep cyclogenesis over the Great Lakes region on Monday and exact position of mass fields would determine if we have a breezy/windy, wet and cool Monday, or just breezy and lower rain/shower coverage if main forcing for precip passes just north and east. For now, the lower-end NBM PoPs appear reasonable. At least a few days of below to well below normal temperatures appear likely behind Monday`s (day 7) secondary cold front passage. Castro && .AVIATION... For the 00Z TAFs... There are no major aviation impacts for the next 24 to 30 hours. Light south-southeast will trend toward southwest on Tuesday. Passing mid-upper level cirrus, coupled with occasionally smokey skies at ~10,000 feet will prevail through the TAF period. KMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
914 PM EDT Mon Sep 21 2020 .SYNOPSIS... High pressure will gradually build over and then south of the area through the week while Teddy departs through the Canadian Maritimes. A cold front will approach this weekend. && .NEAR TERM /THROUGH TUESDAY/... Another chilly night with lows in the mid 30s where Frost Advisories are in effect. Could still see a few spots drop below freezing like we had this morning, but not expecting a widespread freeze although it sill should turn out cooler than this morning. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... While notable weakening in the surface ridge is expected, the region will be coming off another chilly night. Areas of frost are likely to start off Tuesday morning, mainly west of the Blue Ridge and into colder sections of northern Maryland. Gradually all locations will warm up as nocturnal radiational inversions are mixed out by mid-morning. On the synoptic scale, a powerful upper trough is forecast to be located well off the Atlantic coast as Hurricane Teddy is steered toward the Canadian Maritimes. Farther upstream along the Eastern Seaboard, a transient shortwave ridge moves through which bumps temperatures up a bit. With 1000-500 mb thicknesses rising by around 3 to 5 dm from the previous day, expect afternoon highs to reach the low 70s accompanied by low dew points. Heading into Tuesday evening and night, additional western U.S. wildfire smoke will again enter the picture. Recent HRRR smoke loops and cross-sections show mid to upper-level smoke filling the skies. While this will not influence surface visibilities, it should create a hazy appearance in the sky. These conditions are likely to be in place at least through Wednesday which may keep temperatures down during the afternoon. Most ensembles bring highs to around 80 which may be difficult to muster depending on how much smoke limits incoming solar radiation. Unlike previous nights, Wednesday night will be much milder given an increase in cloud cover and the surface high shifting its position into the Tennessee Valley. && .LONG TERM /THURSDAY THROUGH MONDAY/... Overall good agreement amongst guidance in regards to the extended period. High pressure will remain offshore Thursday into Friday, resulting in continued dry conditions. Meanwhile, the leftover moisture from Beta will be picked up by the southern jet stream as it slowly moves eastward. Strong high pressure over the Gulf of Maine may suppress most of the moisture south of our CWA, keeping the bulk over southern VA/NC. However, cannot rule out some shower activity both Saturday and Sunday as a decent amount of uncertainty remains. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... VFR expected thru Wed night. HRRRX cross sections and upstream satellite suggest smoke from western wildfires is again likely to move over the area by around nightfall Tuesday and persist through Wednesday as low as 8-12 kft AGL. VFR conditions are expected Thursday and Friday with high pressure offshore, coupled with a light southerly flow. Patchy fog may briefly reduce vsbys during the early morning hours both days. && .MARINE... Winds have diminished and model trends indicate winds continue to weaken tonight as high splits and settles over the area. Have canceled advisories. As the high center weakens and shifts south, winds will become westerly Tuesday into Wednesday. High pressure will build offshore Thursday and Friday, and a southerly flow is expected. However, the gradient should be light enough for winds to remain below SCA criteria most of the time. && .TIDES/COASTAL FLOODING... Onshore flow will maintain elevated water levels through tonight. Minor flooding is likely for sensitive areas with the high tide cycle through high tide Tue morning. The flow will turn more westerly for Tuesday and may cause anomalies to decrease. However, there will be water piled up near the mouth of the Bay, and some of that water may still make it into our area since the flow will be relatively light. Therefore, minor flooding is still possible. Confidence is low at this time. && .EQUIPMENT... The KLWX (Sterling, VA) WSR-88D is out of service until further notice. The outage is due to a failure within the Radar Data Acquisition Functional Area that occurred early in the morning on September 20, 2020. KLWX will be out of service for at least several days, as subject-matter experts from the National Weather Service Radar Operations Center will diagnose the failure, and then perform maintenance action in order to return-to-service. Users of KLWX can utilize adjacent weather radars located in Dover DE (KDOX), Mt. holly NJ (KDIX), Pittsburgh PA (KPBZ), Charleston WV (KRLX), Blacksburg VA (KFCX), and Wakefield VA (KAKQ). Further updates to keep users informed about the situation will be issued as information becomes available. Thank you for your understanding during this extended outage. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Coastal Flood Advisory until 2 AM EDT Tuesday for DCZ001. MD...Frost Advisory until 9 AM EDT Tuesday for MDZ003>006-501>503- 505-507. Coastal Flood Advisory until midnight EDT tonight for MDZ014. Coastal Flood Advisory until 8 AM EDT Tuesday for MDZ017. VA...Frost Advisory until 9 AM EDT Tuesday for VAZ025>031-040-051- 501>505. WV...Frost Advisory until 9 AM EDT Tuesday for WVZ050>053-055- 501>506. MARINE...None. && $$ SYNOPSIS...LFR/DHOF NEAR TERM...LFR SHORT TERM...BRO LONG TERM...MSS AVIATION...MSS/LFR MARINE...MSS/LFR TIDES/COASTAL FLOODING... EQUIPMENT...LWX
Area Forecast Discussion
National Weather Service Marquette MI
842 PM EDT Mon Sep 21 2020 .SHORT TERM...(This evening through Tuesday) Issued at 424 PM EDT MON SEP 21 2020 Water vapor imagery and RAP analysis show a mid-level low along the Manitoba/Ontario border to the ne of Lake Winnipeg. 850mb theta-e ridge that was advected ne ahead of a shortwave that pivoted around the low currently runs from se SD ne across western Lake Superior. Theta-e advection to the e of the axis along with steep mid-level lapse rates of 7-8C/KM is supporting sct high based radar returns in a sw-ne band from around the Twin Cities to eastern Lake Superior. Given the dry air noted on the 12z GRB/MPX soundings, probably not much more than sprinkles reaching the ground from much of these echoes over the fcst area. Some lightning is beginning to show up to the sw in WI where MUCAPE increases to around 500j/kg. Otherwise, it`s been a partly to mostly sunny, breezy day with wind gusts generally in the 20-30mph range. Temps have pushed into the mid 60s to mid 70s. Into the evening hrs, 850mb theta-e axis will shift e just ahead of 850mb trof which will clear the fcst area during the night. Theta-e advection and steep mid-level lapse rates will continue to result in a relatively narrow band of sct high based -shra developing thru the evening hrs. With an axis of several hundred j/kg of MUCAPE in the 1- 3km layer ahead of the 850mb trof, expect some rumbles of thunder as well. Convection will shift w to e during the night, exiting the eastern fcst area overnight. Breezy conditions will continue into early evening. Otherwise, expect a mild night with lows in the 50s. Tue will be a dry day with sfc high pres ridge moving over the area. Under 850mb temps of 12-14C, it will be a warm late Sept day under mostly sunny skies. Expect max temps in the 70s. A few spots over the interior s central may reach 80F. With the sfc high pres ridge arriving, lake breezes will develop across the board, providing some cooling lakeside in the aftn. .LONG TERM...(Tuesday night through Monday) Issued at 400 PM EDT MON SEP 21 2020 The long-term period begins with continued ridging Tuesday night and Wednesday. NAEFS 850 mb temps are progged to remain around the 90th percentile for this time of year, and with mostly sunny skies and deep mixing, should have no problem translating that into highs in the mid to upper 70s. Weak background flow will allow afternoon lake breezes to develop, keeping the immediate lakeshores in the upper 60s to low 70s instead. By late Wednesday afternoon, a short wave riding along the northern periphery of the ridge will begin to dip down across the Upper Great Lakes bringing a chance of showers with it. Expect a weak warm front to develop across the U.P. with showers and possibly storms riding southeastward along it. Showers and perhaps some elevated thunderstorms (mostly weak) look likely Wednesday night, especially early on. Given the run-to-run consistency in the models, increased POPs over NBM initialization to get some likely POPs for the west half. Also included chance thunder out west given anywhere from 500 to a little more than 1000 J/kg MLCAPE in the models. Given storms will probably be elevated, used 1-6 km bulk shear vectors; those are still around 30 kts which could support some modest storm organization. However vectors are parallel to the boundary, which would probably mean training multicells, if that. The question for Thursday will be how amplified the system is and if the UP can end up getting into the clear warm sector before the cold front arrives on Thursday. The 12z NAM shows this happening with MLCAPE and deep-layer/low-level shear at least marginally supportive of strong to severe thunderstorms... but other models do not show this happening. Given the cold flow off Lake Superior and the NAM`s bias towards deeper surface cyclones in the medium range that don`t verify, think a GFS-like scenario is the more likely outcome. That ends up being just cloudy skies for the north half and some showers and maybe isolated weak storms lingering along the southern edge of the CWA. Short wave ridging building in behind this wave leads to another warm and mostly sunny day Friday. A 30-40+ kt LLj moving in ahead of the next wave will lead to breezy south winds on Friday, especially if cloud cover holds off (which right now it looks like it will). Will likely need to increase winds during for the Friday afternoon period in future forecasts. By Saturday, models are in good agreement that a more potent mid-level wave will be digging into the Northern Plains and a cold front pushing east. This front will likely be the focus for numerous showers on Saturday, as well as possibly some thunderstorms given model progs of 1000 J/kg or more MUCAPE. In addition to any pre-frontal convection, models (especially the GFS) show a classic anafront precip pattern with the upper-level jet oriented such that the right entrance region falls behind the front. Therefore, a soaking rain is likely to continue behind the front for much of Saturday night as well. Looking even farther out, the GFS continues to advertise a very strong system early next week followed by a return to more seasonably chilly air. Today`s 12z EC shows a similar solution as well, albeit not as strong. Still plenty of time to see how that evolves in the models over the next couple of days. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 832 PM EDT MON SEP 21 2020 Isold -shra into early evening at KSAW, but otherwise expect VFR conditions with clearing skies from the west overnight. Low- level jet will be shifting e of the area later tonight, but there will be a period this evening when decoupling winds may result in LLWS at KSAW before the low-level jet departs. Under building sfc high pressure, expect light winds with developing lake breezes on Tuesday. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 424 PM EDT MON SEP 21 2020 Pres gradient will finally weaken tonight as a weakening sfc trof crosses Lake Superior, followed by a high pres ridge which will arrive over the lake on Tue. As a result, ongoing 20-30kt winds over a good portion of the e half of Lake Superior will diminish to 15- 25kt tonight. Could be a few gale force gusts this evening at high obs platforms and toward the nearshore waters e of Marquette. Over the w half, winds will mostly be under 20kt tonight, though some gusts to 25kt are expected. Winds will fall off to under 15kt Tue thru Wed with passing sfc high pres ridge. A cold front will cross Lake Superior Wed evening. With weakening low pres along the front over the Upper Mississippi Valley and high pres shifting se across northern Ontario, ne winds may ramp up to 20-30kt for a time across the w half of Lake Superior late Wed night/Thu morning. Otherwise, winds will be mostly under 20kt Thu into Fri morning. Southerly winds will then increase Fri/Fri night, strongest over the e half where winds should reach 20-30kt. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...RJC AVIATION...Voss MARINE...Rolfson
Area Forecast Discussion
National Weather Service New York NY
739 PM EDT Mon Sep 21 2020 .SYNOPSIS... High pressure will remain in control through Tuesday. High pressure remains over centered over the Mid-Atlantic into Thursday before a weak frontal system approaches from the Great Lakes into Friday. High pressure returns to start the weekend period as a stronger cold front approaches the region for early next week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Forecast is on track this evening. Have trended temperatures and dewpoints down a bit to reflect current trends. Otherwise, tranquil conditions are forecast tonight with high pressure remaining over the northeast. Winds will diminish and combine with clear skies to promote excellent radiational cooling conditions. Temperatures are expected to fall into the middle 30s across the interior and Long Island Pine Barrens, with lower to middle 40s most elsewhere. Areas of frost are likely across the interior and have issued a frost advisory from 2 am to 9 am Tuesday. There is a high risk of rip currents at the Atlantic Ocean beaches through this evening due to high seas and long period swell. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... The surface high will weaken on Tuesday as it shifts to the south and west of the region. Teddy will lift to the north and continue to become extratropical as it merges with a strong upper low off the New England coast. The repositioning of the surface high and Teddy passing offshore will create a stronger pressure gradient and result in a bit breezier conditions. Otherwise, highs will moderate back closer to normal in the lower 70s. Mostly clear conditions are forecast Tuesday night, but there may be some increase in smoke aloft from the wildfires across the west as it moves around the periphery of the upper level ridge. This is supported by the vertically integrated smoke field of the HRRR. The hazy sky could persist into Wednesday morning. Lows will likely be much milder than recent nights, falling into middle and upper 40s inland and 50s elsewhere. There is a high risk of rip currents at the Atlantic Ocean beaches on Tuesday due to high seas and long period swell. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Surface high pressure remains anchored over the mid-south as Teddy heads well to the northeast. As a result the pressure gradient relaxes by Wednesday afternoon. The surface high slides east on Thursday as surface winds locally will become more southerly by Thursday afternoon. Temperatures and moisture will be on the increase, as warm advection commences under the southerly flow. Temperatures begin to feel more climatologically normal for this time of year. HRRR is also showing vertically integrated smoke passing well overhead again on Wednesday afternoon. This will remain at very high levels and appear like thin cirrus overhead. Back to the west an upper trough takes shape over the OH Valley and brings through a weak cold front by Friday. Guidance continues to keep the area basically dry, with the bulk of any precipitation staying south of the area where upper forcing is a bit better. The front clears the coast by Friday afternoon and the upper trough axis swings trough by early Saturday. Upper ridging then builds in for the weekend with high pressure to the northeast and mainly dry and seasonable conditions, with highs in the mid to upper 70s. A deep upper trough and cold front approach by Monday morning bringing a rain chance by Monday afternoon into Tuesday. Models are differing on the evolution of this system the ECMWF increasing cloud cover and shower chances by Sunday evening with the weak development of surface low south of the area ahead of the main system. The GFS, however is keeping us mainly dry until Monday afternoon with the passage of the front. Given the Days 6-7 timeframe and inherent uncertainty, for now have increased PoPs on both Sunday afternoon and Monday. Temperatures look to remain seasonable, or just above. There is a high risk of rip currents at the Atlantic Ocean beaches on Wednesday due to lingering high seas and long period swell. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... High pressure will be stationary and north of the region, remaining in control through the TAF period. VFR conditions will prevail through the TAF period and winds will remain in a general N-NE flow but back to more NW-N on Tuesday. Winds tonight and overnight near 5 kts. Sustained winds will be near 10-12 kt by late morning. Gusts mainly to 20-24 kt are expected by the afternoon and subside after 23Z Tuesday. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Magnitude and duration of gusts may extend a little longer into Tuesday evening especially eastern terminals. .OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY... .Tuesday Late afternoon...VFR. N-NW winds with gusts to 24 kt. .Wednesday through Saturday...VFR expected. Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ && .MARINE... No changes were made to the SCA that goes through Wednesday afternoon. Winds on the ocean will gust 20-25 kt tonight and then 25-30 kt on Tuesday into Tuesday night. There may also be occasional gusts around 25 kt on the eastern LI Bays and eastern LI Sound. If the gusts look more frequent, then an SCA will be needed here on Tuesday. Elevated seas will remain on the ocean due to long period swells from Hurricane Teddy which will pass well east of New England on Tuesday. See the National Hurricane Center for official forecasts on Teddy. Atlantic ocean seas will remain elevated on Wednesday, with 4-6 ft wave heights across the waters diminishing by Wednesday evening. Wind gusts may approach 20 kts as well on Wednesday afternoon. Winds and seas are expected to remain below small craft levels from Thursday through SUnday evening. Small craft conditions may return by Monday. Waves of 4-6ft and gusts nearing 20kts may be possible across the Atlantic Ocean waters, in association with an approaching cold front. && .FIRE WEATHER... A warmer and drier day is forecast on Tuesday with min RH values less than 30%, particularly across CT. Winds may also end up a bit stronger. A Special Weather Statement was issued this evening for southern CT through Tuesday evening as a result. && .HYDROLOGY... No hydrological concerns are anticipated through next Monday. && .TIDES/COASTAL FLOODING... Astronomical high tides will continue to run high and will combine with long period swells and high seas from distant Hurricane Teddy in the Atlantic. The higher of the tides continues to be during the day time. Tide levels are forecast to remain below benchmarks tonight and Tuesday night. Widespread minor coastal flooding is likely Tuesday afternoon along the south shore back bays of Nassau and Queens as well as Southern Westchester and Southern Fairfield on Tuesday. Isolated minor is forecast for the rest of the Long Island coast and lower NY Harbor with the Tuesday afternoon high tide. Another episode of minor coastal flooding is possible on Wednesday afternoon as long period swells will only slowly subside. However, have held off on any products for Wednesday until confidence in total water levels increase. The high surf advisory has been extended through 6 am Wednesday. Wave heights of 7 to 12 ft are forecast, highest into Tuesday. Widespread dune erosion and scattered overwashes expected for the ocean beachfront today through Tuesday evening. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Coastal Flood Advisory from 2 PM to 6 PM EDT Tuesday for CTZ009. Frost Advisory from 2 AM to 9 AM EDT Tuesday for CTZ005>008. NY...Coastal Flood Advisory from 2 PM to 6 PM EDT Tuesday for NYZ071. Frost Advisory from 2 AM to 9 AM EDT Tuesday for NYZ067-068. High Rip Current Risk through Tuesday evening for NYZ075-080- 081-178-179. High Surf Advisory until 6 AM EDT Wednesday for NYZ080-081-178- 179. Coastal Flood Advisory from 11 AM to 4 PM EDT Tuesday for NYZ178-179. NJ...None. MARINE...Small Craft Advisory until 6 PM EDT Wednesday for ANZ350-353- 355. && $$ SYNOPSIS...DBR/DS NEAR TERM...DBR/DS SHORT TERM...DS LONG TERM...DBR AVIATION...IRD MARINE...DBR/DS FIRE WEATHER...DBR/DS HYDROLOGY...DBR/DS TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Pittsburgh PA
758 PM EDT Mon Sep 21 2020 .SYNOPSIS... Dry weather with gradually warming temperature can be expected this week under high pressure. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Another good radiation night under dry high pressure will support a rapid temperature drop. With dewpoints in the lower 30s, a little more moisture is available for frost formation, so an advisory was issued for the extreme northern, and ridge zones of the Upr OH Valley Region. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... Persistently pleasant weather will prevail through midweek with surface high pressure. A gradually warming trend is likely as weak warm advection resumes on the west side of high pressure in the low- levels, with each subsequent day likely being a slightly warmer than the preceding day. Overnight lows both Tuesday night and Wednesday night will be warm enough to preclude any frost development. HRRR vertically integrated smoke indicates upper-level smoke will return by Tuesday afternoon. && .LONG TERM /THURSDAY THROUGH MONDAY/... A shortwave trough will lose amplitude as it moves across the Central CONUS to the Upper OH Valley region by Thursday. Cloud cover will increase with its approach and passage, though a lack of deep layer moisture should preclude rain chances. Ridging building across the Eastern CONUS, ahead of an approaching Central CONUS trough, should result in clearing skies and dry weather through the first half of the weekend. The trough is progged to approach the Upper Ohio Valley region Saturday night and Sunday, resulting in scattered showers. Temperatures are expected to average 5 to 10 degrees above seasonable levels through the period. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... High pres wl cont to maintain VFR and lgt wind, marred only by some brief and shallow peri-dawn fog at terminals next to the rivers. .Outlook... VFR is likely to prevail into the weekend despite the remnants of TS Beta advancing north. Low and mid-level dry air will keep cigs above 4kft. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...Frost Advisory from 2 AM to 9 AM EDT Tuesday for MDZ001. OH...None. PA...Frost Advisory from 2 AM to 9 AM EDT Tuesday for PAZ009-015-016-023- 074-076. WV...Frost Advisory from 2 AM to 9 AM EDT Tuesday for WVZ512>514. && $$
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
458 PM MDT Mon Sep 21 2020 .DISCUSSION...(This Evening Through Monday) Issued at 150 PM MDT Mon Sep 21 2020 Main fcst problem this afternoon revolves around how fast smoke/haze will push back into cwa later this evening/overnight...and fire weather concerns for Tuesday and again on Thursday. Departing low across srn Canada will result in quick moving zonal flow at 500hpa level across upper midwest through mid-week. Embedded minor waves would provide a spark of interest...but very dry lower layers look to prevent any measurable pcpn pops from being inserted into fcst. WAA moves in at 850hpa level with flow moving more sw. HRRR smoke fcst also shows increasing smoke/haze intruding into cwa beginning 00z tonight and increasing through the next 24-36 have increased coverage in the wx grids to account for this. With the warmer temps weather concerns raise eyebrows...especially across wrn cwa. However...lack of sfc winds prevents any headlines at this time. Then for Thursday...seems like a slightly better chance for fire weather headlines as winds in the sw cwa increase with the waa pattern. This far out...will monitor. Best chances for pcpn appear to be on the weekend as stronger 500hpa/700hpa trofs push through the region. Again...scant moisture to work with...but a bit better dynamics around. This system results in highly amplified CONUS pattern with west coast ridge/east coast trof for next week. && .AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening) Issued At 451 PM MDT Mon Sep 21 2020 Smoke will begin moving back into the region tonight, but expecting conditions to remain VFR through Tuesday. && .FIRE WEATHER... Issued at 150 PM MDT Mon Sep 21 2020 Warm and dry conditions will continue through the forecast period...with Tuesday and Thursday being the most critical days for fire weather concerns. Hot temps and low Rh values will be present on both days...but winds will be strongest on Thursday. The best pcpn chances are Saturday when a stronger cold front moves through the region. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION...Hintz AVIATION...Pojorlie FIRE WEATHER...Hintz