Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/12/19

Area Forecast Discussion...Updated
National Weather Service Billings MT
834 PM MST Wed Dec 11 2019 .UPDATE... Light snow showers continued over eastern areas this evening as a shortwave tracked east into the Dakotas. Snow will gradually diminish through the remainder of the evening over the plains. Patchy fog is possible from Miles City to Baker late tonight and tomorrow morning. At the same time, snow will increase over the southwest mountains tonight as a plume of Pacific moisture works into the region. The Winter Storm Warning for the Beartooth/Absaroka mountains in effect from midnight tonight remains on track. Have adjusted temperatures, pops, and sky cover to reflect latest trends and observations. The rest of the forecast looks to be in good shape and the previous discussion and an updated aviation discussion are below. STP && .DISCUSSION... Tonight through Thursday Night... Satellite imagery shows a shortwave moving through central Montana, an area of drier air over the northern Rockies (just upstream of our area), and a moist westerly flow spreading into the PacNW. At the surface, lee side surface low remains but there are pressure rises noted along the MT/Canada border. Winds have been decreasing at Livingston and have cancelled the wind advisory for the Livingston area and Beartooth Foothills. Winds at these locations will remain elevated tonight through Thursday night, with some gap enhancement again tomorrow, but currently we expect gusts to remain at 50 mph or less. A heads up for travelers on I-90. Moist Pacific flow will bring a period of accumulating snowfall to west aspects of the Beartooth Absarokas late tonight thru Friday. This appears to be a typical heavy snow set-up for the mountains around Cooke City with convergent mid level winds, and a deep moisture fetch extending west to near the dateline. Have upgraded the Watch to a Winter Storm Warning for 12-18" of snow from midnight tonight through Friday. By Friday, jet energy and deeper moisture will sag to our south. Heaviest snow should occur on Thursday. Shortwave currently in central Montana will bring some light precip to our eastern cwa between now and 03z. There was a concern that some precip could be in the form of light freezing rain, with an elevated warm layer on top of cold valleys, but spotter reports, web cameras and local observations all support the precip being just snow. Once this exits to our east, we will see another weak backdoor front slide into our east bringing another reinforcement of colder air and quite possibly some low stratus. HRRR is suggestive of fog late tonight and while it may turn out to be just low cloud, have added patchy fog to Miles City and Baker after 06z tonight. Next Pacific shortwave on Thursday may produce some very light showers at our lower elevations, but downsloping will keep things mainly dry. Subsidence behind this wave will push stronger west winds to Big Timber and Harlowton tomorrow afternoon, with gusts near 50 mph possible. By late Thursday night, we may begin to see the effects of the next Canadian fropa, a stronger one which could produce some snow at lower elevations on Friday. Temperatures over the next 36 hours will continue to moderate. Look for widespread 40s on Thursday, with the exception of lingering 30s in the cooler air in our far east. JKL Friday through Wednesday... Unsettled pattern persists through the first half of the extended forecast period. Elevated winds will also continue to be a concern in the Livingston/Nye Friday, and again at the beginning of next week. A backdoor front will slide into the region late Friday, bringing cooler temps and a chance for snow to our CWA. The high temp of the day is expected to occur early in the day, decreasing throughout the rest of the day behind the front. Heaviest precip is expected mainly over the central zones to just west of Billings. At this time, the front does not appear to reach foothills, before beginning to recede. That said, would not be surprised if this changes, so have kept lower PoPs in place in foothill and further west. Uncertainty does remain relatively high, based on expectations of developing snow band, which could be stationary at times. Current models keep band moving, but do favor a period of heavier precip over central zones for a time, as front moves in Friday, and recedes late Friday night. Front sliding east Saturday necessitated most significant change, which was to add and increase pops for eastern zones Saturday. Also lingered PoPs over the east into Sunday morning. Winds will remain gusty near Livingston/Big Timber area early Friday, before decreasing as the front moves in later in the afternoon. Winds are expected to pick back up again as front recedes Sunday. Models point to another period of strong and gusty winds in this area to start the work week, but specific remain a bit uncertain. Have kept at subadvisory levels at this time. High temps Friday will vary significantly with FROPA, but should generally see mid 20s east to upper 30s west. Temps in the 30s will continue for the western and central portion of the CWA through early next week, while areas along the ND border will remain in the teens and 20s. Gilstad && .AVIATION... Scattered light snow showers will produce local MVFR east of KBIL though the evening. After the precip ends, a combination of low clouds and fog is expected to produce MVFR or lower conditions near KMLS and KBHK late tonight into Thursday morning. To the west, VFR will prevail over the next 24 hours, w/ westerly winds. Expect gusts of 30-45 kts at KLVM. A moist Pacific flow will bring snowfall and obscured tops to the Beartooth Absarokas late tonight through tomorrow. JKL && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 028/046 031/039 021/034 019/033 019/035 020/038 021/037 01/B 34/O 53/S 21/B 11/B 10/B 11/B LVM 032/046 031/038 022/032 017/029 018/032 020/036 021/035 15/W 45/O 42/S 21/N 12/S 20/N 11/N HDN 021/046 025/038 015/033 014/032 013/032 015/038 017/036 21/B 35/O 53/S 21/E 11/B 10/B 11/B MLS 016/039 022/028 010/022 012/028 013/030 017/035 015/032 22/W 24/S 23/S 21/E 00/B 11/B 11/B 4BQ 018/041 024/036 012/029 013/028 013/030 015/035 016/035 21/B 24/O 22/S 22/S 00/B 10/B 00/B BHK 010/037 018/025 002/018 007/025 010/025 012/031 012/029 30/E 12/S 12/S 22/S 00/B 11/B 01/B SHR 019/045 023/038 014/032 011/030 010/032 012/038 016/039 01/B 34/O 42/S 22/S 11/B 11/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning in effect from midnight tonight to 5 PM MST Friday FOR ZONE 67. WY...None. && $$
Area Forecast Discussion
National Weather Service Caribou ME
1003 PM EST Wed Dec 11 2019 .SYNOPSIS... An Arctic cold front will cross the region tonight. Cold Canadian high pressure will build over the region Thursday. A warm front will lift north of the area Friday. Low pressure will lift north across Maine Saturday. A cold front will cross the region Sunday. High pressure will build toward the region later Monday. && .NEAR TERM /THROUGH THURSDAY/... 10 PM Update... Adjustments were made to the precip coverage w/a band of light snow associated w/a a pre-frontal trof was pushing east. The latest radar showed light returns moving east across northern and central Aroostook County. Mesoanalysis showed some convergence w/this band. Therefore, decided to bring snow showers in a bit earlier and further to the east. Obs showed some warming indicative of weak WAA aloft w/the boundary. K40B(Clayton Lake) rose to 16 degs the last hr. Tweaked the hrly temps to take this warming into accounts. The cold front that is expected to move through by early Thursday morning was still back across the Maine-Quebec border. Regional radar showed a line of enhanced reflectivity w/the front. Some of the dynamical parameters from the HREF, RAP and NAM12 point to the potential of a few snow squalls later tonight moving across western and then into northern areas. The previous forecast looks to have this handled well and little adjustment was needed. Previous Discussion... The cold air advection and bitterly cold northwest winds will be the primary byproducts of the front for later tonight into Thursday. The only precipitation will be a brief snowshower with fropa, mostly in Aroostook County. Lapse rates steepen briefly with the front, but the front moves so quickly that accumulations more than a half-inch in a squall seem unlikely. The snow squall parameter does flash a signal after midnight in northern Aroostook County with those steeper lapse rates and potential gusts to 40 mph. Thus visibility in a squall could briefly go to zero for pre-dawn travelers in that region. The air is so cold that St Lawrence moisture may continue to provide flurries in the Saint John Valley well into Thursday morning. Highs on Thursday will only reach the low teens in northern Aroostook County and no more than the lower 20s towards Bangor and the coast. More notable will be subzero wind chills through the day in the northern half of the forecast area, and just single digits in the southern half of the forecast area. Winds will start to decrease during the afternoon as the high builds and radiational cooling will get off to a quick start after sunset. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... High pressure begins to exit across the Maritimes Thursday night, with a developing warm front across the region. Clouds will increase across the forecast area Thursday night, with a chance of snow showers across northern areas in the vicinity of the developing warm front. The warm front lifts north Friday. Expect mostly cloudy skies across the region Friday with a slight chance of snow or snow showers. The warm front moves north of the region Friday night, with developing low pressure across the Mid-Atlantic region. Expect rising temperatures Friday night with warm advection. Moisture also begins to expand north in advance of the Mid-Atlantic low with increasing precipitation chances. Across Downeast areas, expect a rain/snow mix early Friday night which will transition to rain overnight. Snow will transition to a snow/rain mix across central portions of the forecast area, with mostly snow across northern areas. The intensifying low lifts north across New England Saturday. Precipitation will remain in the form of rain Downeast Saturday. Snow will transition to rain across the remainder of the region through Saturday morning into the afternoon. Total snow accumulations through early Saturday, before the transition to rain, will generally range from 1 to 3 inches across the north and mountains with the greater totals across the Saint John Valley and higher terrain areas. Snow totals diminish southward across the forecast area with less than an inch expected across Downeast areas. Temperatures will be at near normal levels Friday, warming to above normal levels Saturday. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... The low will lift across Maine Saturday night, reaching northern Maine late. Rain will persist Saturday night with near steady temperatures. The low will lift across the Gulf of Saint Lawrence toward Labrador Sunday. The low will draw a cold front across the region Sunday morning into the afternoon, though the exact timing is still uncertain. The heavier precipitation will exit across the Maritimes in advance of the cold front. Precipitation will remain in the form of rain in advance of the cold front, then transition to snow or snow showers following the cold front. Gusty southwest/west winds will develop following the cold front then persist into Monday. Snow showers could also linger across the north and mountains Sunday night into early Monday with partly cloudy/mostly clear skies Downeast. High pressure will build across the region Monday with decreasing winds along with partly cloudy/mostly clear skies. Low pressure should affect the region Tuesday. However, the track of the low remains uncertain. Precipitation types/amounts will be dependent on the eventual track. The low should exit across the Maritimes Wednesday. Generally expect partly/mostly cloudy skies Wednesday, with a chance of snow showers. Temperatures will be at above normal levels in advance of the cold front Sunday. Below normal level temperatures are expected Monday through Wednesday. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... NEAR TERM: VFR conditions are expected outside snow showers with the cold front, mostly at FVE. These snow showers could provide tempo IFR vis. Low level wind shear is possible at sites north of BHB later tonight into early Thursday morning. SHORT TERM: Thursday night...VFR early. MVFR/IFR conditions developing overnight. A chance of snow showers across northern areas. Friday...VFR/MVFR. A slight chance of light snow or snow showers. Friday night...Conditions lowering to IFR/LIFR levels with snow north, a snow/rain mix across central areas and snow changing to rain Downeast. Saturday...IFR/LIFR. Snow or a wintry mix transitioning to rain north, with rain Downeast. Sunday...IFR/LIFR early. MVFR/IFR during the afternoon, then VFR/MVFR late. Rain early. Precipitation transitioning to snow or snow showers following a cold front. Gusty southwest/west winds following the cold front. Monday...VFR/MVFR early, then VFR. A chance of snow showers early across the north and mountains. Gusty west winds. && .MARINE... NEAR TERM: Continue to anticipate a quick hitting gale later tonight into early Thursday morning. SCA conditions will follow the gale into later Thursday afternoon. SHORT TERM: Conditions below small craft advisory levels Thursday night. Small craft advisory conditions Friday through Saturday, with gusts possibly approaching gale levels later Saturday. Visibilities reduced in rain Friday night through Saturday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 9 AM EST Thursday for ANZ052. Gale Warning until 9 AM EST Thursday for ANZ050-051. && $$ Near Term...Hewitt
Area Forecast Discussion
National Weather Service Cleveland OH
929 PM EST Wed Dec 11 2019 .SYNOPSIS... A ridge of high pressure over the region this morning will get pushed south as a cold front moves through the eastern Great Lakes this afternoon. Behind the front, high pressure will reassert itself over the Ohio Valley for Thursday before moving off the East Coast for Friday. A pair of low pressure systems will then surround the region for the weekend, as a low moves through the northwest Great Lakes, eventually merging with a stronger low moves up the East Coast. && .NEAR TERM /THROUGH THURSDAY NIGHT/... A westerly low-level flow of cold air should continue directing bands of light lake effect snow in/near the snowbelt of northeast OH and northwest PA before these snow bands dissipate by the predawn hours of Thursday morning. As high pressure at the surface and aloft builds from the west, decreasing low-level moisture, a lowering subsidence inversion, and decreasing lake- induced instability will lead to the eventual demise of this lake effect snow. Outside the lake effect snow, light snow showers are also moving eastward across interior portions of north-central and northeast OH. Latest RAP data suggest these snow showers are associated with lift along and ahead of a subtle shortwave trough axis. As the shortwave trough axis continues moving eastward, these snow showers are expected to end from west to east through 10 PM this evening. Any additional snow accumulations here in our CWA will likely be less than an inch. Over and near the snowbelt, skies are expected to remain partly to mostly cloudy through Thursday morning. Lake effect cloud cover over and near the snowbelt should finally exit the area around and especially after daybreak as the low-level flow backs from westerly to southwesterly. However, mid- to upper-level cloud cover associated with isentropic lift should eventually overspread our entire CWA from west to east Thursday morning. Used NBM guidance to update our sky cover forecast to better match observed and expected trends. Also decreased Thursday morning low temperatures by a few degrees for locations outside the snowbelt. 10th percentile low temperature values from all available model guidance were used for this adjustment. Outside of the snowbelt, mainly clear skies, light surface winds, and limited low-level humidity should permit efficient radiational cooling before the aforementioned west-to-east increase in cloud cover. The rest of our near-term forecast remains valid. PREVIOUS DISCUSSION...Heavy lake effect snow over Lake Erie has moved onshore over the past hour or so with winds gusting up to 40 mph. Heavy snow and gusty winds will produce blowing snow and visibilities down to 1/4 mile or less at times. Snow observed elsewhere, near places such as Youngstown, Akron, Canton, and Mansfield is associated with a shortwave trough at 700 mb, which is producing more moisture advection and forcing than predicted by model guidance. Around half an inch or less is expected out of this snow, just enough to put a coating down. Heavy snow is expected to persist through the next few hours especially for Lake, northern Ashtabula and northern Erie. Snow is expected do diminish tonight as moisture decreases as moisture associated with the upper level trough exits the area to our east. Total snow expected through this evening and tonight will be highest across the northeastern part of Erie County, where 3 to 5 inches of snow is expected. Other areas such as Lake, northern Ashtabula, and northern Crawford can expect 1 to 3 inches of snow through tonight. Sustained west winds of 10 to 15 knots with gusts up to 25 to 30 knots will diminish through the evening and tonight as high pressure builds into the area. Temperatures are expected to decrease to the teens tonight and with elevated winds continuing into the evening and early tonight, wind chills could drops into the single digits. High pressure is expected to move the mid-Atlantic by midday Thursday, with southerly winds developing over the CWA by early afternoon Thursday. This should warm temperatures back to the mid to upper 30s by Thursday afternoon. A weak warm front moves north across the area on Thursday night keeping it from cooling down too much Thursday night. No precipitation is expected on Thursday or Thursday night. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... The short term begins Friday with low pressure moving east across the lakes as broad high pressure moves east from New England. Over the next 24 hours the low will dissipate as another low develops through the Central Plains. To our east a coastal low will also begin developing along the Mid Atlantic coast. Between these two systems, moisture will begin to increase out of the south late Friday and Friday night affecting the southern and eastern counties. Saturday, the coastal low will continue rapidly deepening as it moves northeast along the New England coast. The low to our west will be absorbed into the coastal circulation with increased moisture and colder air eventually being wrapped into the back side of the low and across the area Saturday night into Sunday. Will have chance pops into the area Friday night for much of the area as the moisture surges north. For now will have the precip type as rain with a possible mix far northwest towards morning as pops increase to likely east. Saturday will continue with likely pops most areas. Saturday night the precip will begin to mix with then change to snow from the west as cooler air moves in. Pops will be focused more across northeast OH and nwrn PA through the overnight. Drier air will move in from the west for Sunday drying out much of the area while lake effect snow persists across northeast OH and nwrn PA. Highs Friday and Saturday in the 40s. Highs Sunday low to mid 30s. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... The main weather maker for the long term will be low pressure developing out of Texas Monday and moving northeast across the Ohio Valley Monday night and Tuesday. For some, this will be a snow maker and others rain into snow on the back side. At this time, the ECMWF track takes the main low to the New Jersey coast by Tuesday morning while a weak reflection reaching the Pittsburgh area before dissipating. The GFS takes the low across the central lakeshore Tuesday 06z with warm air surging north into the area ahead of the low. At this time, the system is too far out to really nail down details but will have likely pops in place for the event and a mix of precip. Will likely have lake effect develop on the back side of the system Wednesday with 850mb temps dropping to -14 to -18C depending on model but high pressure and dry air will also be building in for again, will not hit too hard. Highs Monday and Tuesday in the mid and upper 30s. Highs Wednesday upper 20s to lower 30s. && .AVIATION /00Z Thursday THROUGH Monday/... Mainly VFR expected next 24-hours. A subtle disturbance aloft will exit our region to the east by 03Z/Thurs, while high pressure at the surface and aloft will build eastward over our CWA through about 18Z/Thurs. Thereafter, a trough at the surface and aloft should begin overspreading the area from the west as the high pressure ridge moves farther east. Lingering bands of light lake effect snow over northeast OH and northwest PA should end between 06Z and 09Z/Thurs, while light snow showers over interior north-central and northeast OH should end from west to east by 03Z/Thurs. Periods of MVFR ceilings and visibility may accompany the snow. Breezy westerly surface winds will become light and variable this evening. Surface winds should then become southerly and breezy around and especially after 12Z/Thurs. .OUTLOOK...Non-VFR possible Friday afternoon through Sunday with rain/snow each night and all rain during the daytime hours. Non-VFR possible with snow and/or rain on Monday. && .MARINE... Will continue with headlines unchanged. Water level will begin rising between 4 and 6 pm but at 3pm was still close to the critical mark. Gales not showing up in shorline obs but HRRR 10m winds suggest 30-35 knots sustained over the water through 00Z before dropping off. Expect a small craft advisory to replace the gale. Winds by morning Thursday should turn out of the south at 10 knots or less but increase through the day to around 20 knots in the open waters and points north. Waves will be highest along the north shore. At this time am not anticipating a small craft advisory my may be close northern reaches of the nearshore waters. Winds will remain fairly light from much of friday through saturday. The next chance of small craft headlines will come Saturday night as winds increase out of the wnw behind deep low pressure in northern New England. Expect winds will reach 20 to 25 knots Saturday night and Sunday. Winds and waves will drop back for Sunday night and Monday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 4 AM EST Thursday for LEZ142>149. && $$ SYNOPSIS...Saunders NEAR TERM...Jaszka/Saunders SHORT TERM...TK LONG TERM...TK AVIATION...Jaszka MARINE...TK
Area Forecast Discussion
National Weather Service Gray ME
941 PM EST Wed Dec 11 2019 .SYNOPSIS... Arctic air mass will drop south through the region tonight with snow showers in the mountains and windy conditions. High pressure will build in and then cross the region on Thursday. Low pressure will track up the East Coast over western New England Friday night through Saturday night bringing mainly rain, possibly heavy rain to the area. Precipitation may briefly start as a wintry mix before quickly changing to rain except in the mountains where the highest elevations may see prolonged wintry precipitation before changing over. Windy and colder conditions follow Sunday into Monday. Another colder system will approach New England Monday night into Tuesday that may bring more wintry precipitation. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 940 PM...The line of SHSN with embedded squalls moving through nrn NH and NW corner of ME attm. holding together fairly well, but HRRR starts to weaken after 03Z, so will go with this idea as it moves away from best forcing and weakening lapse rates. Have increased the POPs in the grids further to the S and E thru about 05Z though. 645 PM...Main issue this evening will be snow showers and potential squalls over the far nrn zones, as second surge of cold air moves in with wave aloft. Pretty good band coming across nrn half of Lk Champlain attm, with secondary bands in the Adirondacks and Mohawk vly of NY. These bands are currently being enhanced by Lk Effect off Ontario, and will likely loose some of their punch as they work way into the nrn half of NH. Still the nrn part of the band may hold together better given it`s proximity to best forcing aloft, and so areas N of the White mtns in NH and N and E of Rangeley and Jackman in ME are where the best chc for a squall exists this evening. Otherwise in and around the Whites and into the Mahoosucs some sct SHSN are expected. Temps should hold where they are until the front goes thru later this evening, and then drop quickly, with lows from 5-10 above in the mtns and in the teens to the south. Previously... As the cold air moves in overnight snow squalls are possible in the mountains. Snow squall parameter continues to highlight the Canadian border from 00-03Z time frame. Further, forecast soundings support this with a shallow saturated layer right in the snow growth zone and steep low level lapse rates. Brief periods of heavy snow with wind gusts to 35mph are possible as this moves through. Have increased the Pops along the Canadian border as well as the Snow amounts for this time period and will issue an SPS to highlight the potential. As cold air moves in overnight expect windy conditions to keep the lower levels well mixed and thus while temps aloft fall to around -17C at 850mb, the mixed will keep the temperatures above zero across the north. Have still leaned a bit on the colder side of guidance as after the initial cold push this evening some calming of the winds may occur in sheltered valleys early tomorrow morning. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... High pressure will build in for Thursday with winds steadily decreasing as the high crests over the region for Thursday afternoon. Stuck with a consensus for the temperatures for what should be a nice day. Thursday night had been looking like the coldest night of the week as the high passes to our east but some mid level clouds may prevent the radiational cooling from taking hold in the north and so have not gone quite as bullish on the cold as past forecasts. Still temperatures will remain in the single digits overnight. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... High pressure will be well east of the area Friday morning with return flow advecting warmer air into the region. Highs on Friday will run 10 to 15 degrees warmer than Thursday with mostly cloudy skies. The next system of consequence will be an area of low pressure that develops over the southeast US Friday. Deterministic and ensemble solutions have come in better agreement with a westward track of this system cutting up into the St. Lawrence Valley. With milder air already moving into the region ahead of this system and a westward track, this system is looking to be a mostly rain event. Precipitation will break out from SW to NE and may briefly start as a wintry mix before quickly changing over to rain south of the mountains. In the mountains precipitation will start as snow changing to a wintry mix before changing to rain Saturday morning except for the highest elevations where snow will last the longest. There are some model differences with regards to QPF with the GFS trending drier while the ECMWF and CMC suggest upwards of 2 inches are possible. High PWATS and good orographic flow have led towards the wetter solutions with 1 to 2 inches of QPF along and south of the mountains. See the hydrology section for information about river flooding. The system moves northeast Sunday with upslope snow showers in the mountains. High pressure builds into the region Monday followed by low pressure tracking from the Ohio Valley towards New England Tuesday. This system looks colder with a track closer to the coast or just offshore. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Short Term... VFR will prevail through the next 36 hours. Another push of cold air moves in tonight and as it does some snow squalls are possible in the mountains with brief reductions to visibility for HIE through to Jackman. NWly flow will continue through evening with VFR and calm conditions for Thursday. Long Term...Low pressure will track over western New England bringing widespread rain to the area Friday night into Saturday night with MVFR likely. Conditions will improve to IFR Sunday into Monday. && .MARINE... Short Term...A secondary cold front pushes through off shore tonight with increasing NWly wind gusting across the waters. Gales will remain in place and have actually increased wind speeds above the median as the low level profiles of cold air over the (relatively) warmer water should help support mixing down of the higher wind speeds from aloft. Long Term...Low pressure tracking up the East Coast over western New England will bring possible gales and elevated seas Saturday morning into Monday. && .HYDROLOGY... Low pressure tracking up the East Coast will bring 1 to 2 inches of rain to the region Friday night into Saturday night. Recent rain and mild temperatures have lead to many rivers in New Hampshire to be running high into the 90th percentile for this time of year. While much of the snowpack south of the mountains has been decimated from recent warmth, NOHRSC estimates show that a ripened snowpack remains from the New Hampshire Lakes Region southwestward towards the border with MA and VT. This snow pack, although heavily reduced will likely melt off with this system and along with rainfall will lead to flooding concerns for rivers in central and southern New Hampshire. Farther north, into the White Mountains a rain on snow scenario will likely serve to moisten the snowpack leading to less runoff and flooding concerns. && .TIDES/COASTAL FLOODING... Low pressure tracking to the west of the area Friday night through Saturday night will bring strong onshore flow and increasing near shore waves. Peak surge with this system is forecast to occur a few hours after the mid-day high tide Saturday and this with near shore waves around 5 to 7 feet may pose some beach erosion and minor coastal flooding concerns. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 7 AM EST Thursday for ANZ151-153. Gale Warning until 7 AM EST Thursday for ANZ150-152-154. && $$ SYNOPSIS...Curtis/Schroeter NEAR TERM...Cempa/Curtis SHORT TERM...Curtis LONG TERM...Schroeter AVIATION...Curtis/Schroeter MARINE...Curtis/Schroeter HYDROLOGY... TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
916 PM EST Wed Dec 11 2019 .SYNOPSIS... High pressure will build south from the Great Lakes through Friday. Another cold front will cross the area Friday night and move offshore early Saturday. High pressure will then build over the region Sunday into Monday of next week. Another front will impact the area early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... As of 915 PM Wednesday...No changes to previous thinking. Strong high pressure centered north of the area will ridge south producing dry weather across NC through Thu. A canopy of widespread Cirrus clouds remains across the area this evening. These clouds are forecast to shift east of the area after midnight resulting in skies becoming mostly clear overnight. As the chilly airmass settles over the region, lows tonight will range from the upper 20s well inland to the mid 30s Crystal Coast and around 40 Outer Banks. Gusty north winds will persist near the coast, but will diminish inland. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... As of 310 PM Wednesday...Strong high pressure will pass by our region to the north during the day Thursday. Despite plenty of sunshine, low-level thickness values only support high temperatures that are similar to just a few degrees warmer than today, with mid/upper 40s inland and low/mid 50s along the immediate coast. Moderate winds continue inland during the day Thursday with gusty winds near the coast. Per latest high- resolution guidance, a stray shower or two may skirt the Outer Banks later in the day. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... As of 310 PM Wed...Periods of unsettled weather expected through the long term period, with roller coaster temps as a progressive/amplified active weather pattern is expected to continue. Thursday night...Thursday night will exhibit a non-diurnal temp curve, with lows likely being realized before midnight, thereafter clouds and increasing TD`s ahead of next system will bring temps up towards daybreak, esp near the coast. There may even be a stray shower that brushes the OBX zones late overnight Thursday. Friday through Saturday...Rain chances inc Fri as deep srly flow increases with digging long wave trough across the lower MS River Valley, which will spur low pressure development over the deep south. This low will ride up the coast rapidly, with rain becoming likely through the day Fri, peaking Fri evening when best UVV/Fgen/PWATS will converge. Maintained the categorical pops this period, as good model to model consistency as well as spaghetti ensembles converging on this solution. Widespread moderate to heavy rain will be possible. Depending on exact track of the low, there could be potential for strong to even severe storms if storm track is further inland. Latest 11/00Z ECM continues to indicate aoa 500 J/KG of sfc based capes advecting into the area with plentiful shear overnight Friday. Upr trough will still be west of the region though deepest moisture will be offshore Sat morning. Could be quite a bit of showers around first half of Sat due to good forcing with upr trough, and have a likely pop for most of the area early, with rapid drying later in the day. It will be mild both days with highs in the 60s. Sunday through Monday...Drier conditions with near to above normal temps expected late weekend to early next week as quasi zonal flow develops. Tuesday...Next potent cold front and possible low pressure system quickly advance towards the region by Mon night or Tue, and introduced high chc pops to account for this. Continued warm as swrly flow ahead of the system will be present. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Short Term /through Thursday/... As of 550 PM Wednesday...High confidence in VFR conditions through the TAF period. Strong high pressure will ridge south into NC through Thu producing dry weather across the area. The low clouds have dissipated with widespread high clouds continuing over the region this evening. These clouds will shift east after midnight with SKC then expected through much of Thu. Some clouds will approach from the east late Thu, but any ceilings should be VFR. Though winds have diminished, good CAA will result in enough low level mixing to preclude any fog formation overnight. Long Term /Thursday Night through Monday/... As of 310 PM Wed...Some increase in clouds on Thurs night ahead of next system. The low pressure area will quickly advance in on Friday, with sub VFR expected possibly into Sat morning with widespread rain showers and low clouds. Return to VFR later Sat into Sun. && .MARINE... Short Term /Tonight and Thursday/... As of 915 PM Wednesday...Gusty N/NNE winds continue on the coastal waters early this evening with a few gusts around 25 kt. Seas continue in the 4-7 foot range. Winds on the Sounds are currently 10-20 knots, but should ramp up after midnight as latest 3km NAM and HRRR show another CAA surge developing and persisting through early afternoon Thursday. Issued a SCA earlier for the Pamlico, Albemarle, Roanoke and Croatan Sounds and the Alligator River for the late tonight through Thursday afternoon period. There may be somewhat of a lull in the winds over the northern coastal waters this evening as well, before ramping up again after midnight in the aforementioned surge. Long Term /Thu Night through Monday/... As of 315 PM Wed...No changes to previous thinking with an active weather pattern expected through the end of the week and into the weekend which will result in hazardous boating conditions with strong winds and elevated seas AOA 6 ft through the period. Winds will continue N 15-25 kt with large dangerous seas continuing above 6 ft will persist through at least Sat as yet another storm system moves through the waters Fri night and Sat with winds switching to srly and swrly 15-25 kt with higher gusts. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Small Craft Advisory from 1 AM to 4 PM EST Thursday for AMZ131- 135-230-231. Small Craft Advisory until 7 PM EST Sunday for AMZ150-152-154- 156-158. && $$ SYNOPSIS...MHX NEAR TERM...JME/CTC SHORT TERM...CTC LONG TERM...TL AVIATION...JME/TL MARINE...JME/CTC/TL/MS