Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/16/20

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
543 PM CST Sat Feb 15 2020 .AVIATION... For the 00Z TAFs, patchy fog is expected to develop late tonight and continue into Sunday morning before dissipating late Sunday morning across the eastern sections of the OK and TX Panhandles. This fog development is forecast to remain well east of the terminal sites. As a result, VFR conditions are expected to continue at KGUY, KDHT, and KAMA through late Sunday afternoon. 02 && .PREV DISCUSSION... /Issued 244 PM CST Sat Feb 15 2020/ SHORT TERM...Tonight and Sunday... Dry northwesterly flow aloft across the Panhandles tonight through Sunday will allow for generally clear skies. Subtle perturbations in the northwesterly flow aloft will result in some high level clouds, however skies should remain generally clear. Surface ridge will build into the forecast area tonight while surface low pressure develops across eastern Colorado and eastern New Mexico tonight through Sunday. Light north and northeast winds will veer around to the east and south tonight and then mainly westerly to southwesterly Sunday. Patchy fog or areas of fog should develop or spread westward into the eastern sections of the Panhandles late tonight through Sunday morning. The fog is expected to affect mainly the areas along and off the Caprock betweeen about 09Z to about 15Z to 17Z Sunday. The HRRR and NAM are forecasting visibilities of as low as about 1 mile to around 4 to 5 miles. The fog should lift by mid to late morning Sunday. Highs on Sunday expected to be well above normal. No precipitation expected tonight through Sunday. Schneider LONG TERM...Sunday night through Friday... The upper level pattern will be shifting to more zonal flow as jet streak rounds broad 250mb northern stream trough across the central plains. Split flow is evident as southern stream jet streak moves up across the southern plains through Monday. These two jet streaks are progged to merge across the MS Valley, with entrance region moving over the Panhandles by Tuesday into Thurs. Split flow is even more apparent looking at 500mb, with at least three separate jet streaks noted in the wind fields going into Tuesday as the main trough deepens from the Pac Northwest. The northwestern Panhandles end up between two speed maxes Monday night into Tuesday. Overall dynamic lift looks pretty weak, and models will likely struggle given the complexity of the split flow pattern. However, the mostly zonal orientation of the jets suggest a lack of better return flow. Indeed, the model soundings for Monday night through Tuesday do not show impressive moisture in the DGZ. Even the NAM solution keeps most of the moisture in the lowest 700mb. That being said, the depth of cold air behind a cold front Monday night may still be sufficient to squeeze out some moisture, even if it is in the lowest 700mb. A 700mb baroclinic zone will be in the area as well, so some very localized 700mb frontogenesis can`t be ruled out. Therefore, while max snow amounts were reduced in the northwest, the area of very light snow was expanded some. Outside of the northwest zones, some drizzle/freezing drizzle will be possible if the NAM solution pans out given the shallow moisture as the cold front moves through. The easterly flow will likely support clouds through the day Tuesday keeping max temperatures down (probably still room to drop). The GEFS members are in good agreement with colder temperatures along with NAM, with operational GFS being the warm outlier Mon - Thurs. The next disturbance continues to trend later and later in the week, now favoring Wednesday night into Thursday as a minor southern stream perturbation advances out of the Baja region and across a cold front. This event still favors better precip chances south of the Panhandles where the best moisture is expected. Lift is mostly tied to jet dynamics with entrance region of departing northern stream jet, while edge of southern stream jet provides some ageostrophic response as well. A warming trend is expected going into weekend ahead of more active weather early next week. Ward && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$
Area Forecast Discussion
National Weather Service La Crosse WI
544 PM CST Sat Feb 15 2020 .SHORT TERM...(Tonight through Sunday) Issued at 157 PM CST Sat Feb 15 2020 Early afternoon analysis showed a surface trough axis and boundary sliding through the forecast area, bringing some very light snow to parts of western and central Wisconsin. Forecast soundings do indicate some loss of in-cloud ice, but also look to struggle to maintain deep saturation, so not expecting much if any drizzle or freezing drizzle to fall anymore. In other words, if anything does fall in a given location, it should be very light snow. For tonight, another surface boundary looks to slide in and bring some cooler air to the area, though not as cold as the past few nights. Expect lows in the single digits above zero. Said boundary then looks to retreat back northward as a warm front on Sunday. Latest guidance has trended toward a good amount of warm air advection, a bit of a moisture surge, and some mid-level frontogenesis working into the area and producing some light precipitation. Model soundings indicate no issue with saturation, so would expect some light snow to fall by mid to late morning across northeast Iowa and southeast Minnesota and work east/northeastward into Wisconsin. Still questions as to how far northeast it makes it, as RAP guidance shows diminishing frontogenesis, but for now have introduced at least some lower-end snow chances to the forecast across much of the area. .LONG TERM...(Sunday Night through Saturday) Issued at 157 PM CST Sat Feb 15 2020 A real up and down weather pattern expected for much of the coming work week, with initial split flow regime consolidating into broad upper troughing for the mid CONUS into midweek before the pattern again flattens out by late week and into next weekend. Pretty solid agreement among guidance regarding the overall upper pattern, with confidence a bit above average for once (haven`t been able to say that too much this winter). By far, the primary feature of interest remains a fast-moving shortwave expected to drop into the local area sometime later Sunday night into Monday, with still just a bit of question about how amplified said wave will end up (NAM/GEM least impressed, GFS the most, with others in between). Forcing, per current trends at least, looks brief but fairly robust, with deep layer warm advection ascent working in tandem with PWAT values around 0.5 inches (roughly 150% of normal for mid February). Toss in some hint of transient frontogenetic forcing and the end result should be a swath of a few inches of snow sometime later Sunday night into Monday. With that said, we may deal with a warm layer at times south of I-90 for some loss of cloud ice issues as well as a potential warmer boundary layer in some of the river valleys, though that will be dependent on timing of precipitation. Given the progressive nature of the system, have a hard time at the moment buying into continued high GFS QPF values with 0.6+ inches, with the GEFS ensemble/WPC/ECMWF mean closer to 0.3-0.4 inches seemingly more reasonable, though we`ll have to watch it closely with some hints of a much more pronounced frontogenetic band into Monday afternoon/evening. All told, may end up needing an advisory for parts of the area given a likely bout of heavier snowfall rates, but we`ll refine those details over the next 24-36 hours. As that system passes Monday night, burgeoning upper ridging through Alaska should drive downstream troughing back across the Upper Midwest into midweek, with mainly dry but progressively colder temperatures by Wednesday as stronger Arctic high pressure works through the region. Looking like another cold night on tap Wednesday night with the low level ridge pretty much overhead, with sub-zero lows likely before gradual moderation takes place by late week and the first half of the weekend along with probably another bout of breezy conditions as is so typical in retreating Arctic airmasses this time of year. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 541 PM CST Sat Feb 15 2020 Skies will be mainly clear through 16.08z and then a 4-8K deck of clouds will rapidly increase ahead of a short wave trough moving into the area from the Northern Plains. These clouds will then linger across the area for Sunday as yet another shortwave trough approaches the region from the Northern Plains. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...CA LONG TERM...Lawrence AVIATION...Boyne
Area Forecast Discussion
National Weather Service Caribou ME
1028 PM EST Sat Feb 15 2020 .SYNOPSIS... A warm front will cross the region overnight through early Sunday. A cold front moves through the area later Sunday night. High pressure builds Monday night. A frontal system approaches from the west Tuesday and tracks across the region Tuesday night. Cold Canadian high pressure builds Wednesday into Thursday. && .NEAR TERM /THROUGH SUNDAY/... Update... A warm front will cross the region overnight through early Sunday. Clouds will increase overnight, with warm advection snow showers also developing. Any snow accumulations overnight will be less than an inch. Low temperatures will occur late this evening then begin to increase overnight with thickening clouds and warm advection. Low temperatures will range from 5 to 10 north, to 10 to 15 interior Downeast with mid teens along the Downeast coast. Have updated the forecast to adjust for current conditions along with overnight temperatures and clouds. Previous Discussion... A jetstreak of 45-50 kts at the 850-700mb layer will provide good forcing ahead of a warm front. Llvl convergence along and just ahead of the boundary w/the NAM and RAP soundings showing the profile to moisten. This should be enough for some snow to develop later after midnight into Sunday morning. The NAM and RAP both show an area of decent frontogenetical forcing from 850-700 mbs setting up across northern and eastern Maine from 09-12Z which will allow for a band of snow to set up and move across the region. Any accumulation of snow looks to be an inch or less w/the best potential across the eastern sections of Aroostook and Washington County. The snow should come to an end by mid morning Sunday w/the best forcing pushing off to the east. SW winds of 10-15 mph and some sunshine returning allowing for temperatures to shoot into the 30s as far n as Frenchville(FVE). && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... The area remains in the warm sector Sunday night. Some clearing and light winds will produce shallow inversions with lows in the teens and lower 20s. The cold front arrives in northern zones later in the night. Low level instability seems most likely in northern Aroostook late Sunday night and will go with chance pops for snow showers. Accumulations should be less than a half inch. The front moves through quickly and weakens before reaching southern portions of the forecast area. The colder air will take some time to filter into the area. As a result, Monday highs will still be in the lower 20s north and above freezing for Bangor and Downeast. Strong radiational cooling seems probable for Monday night as the 1034mb high settles over the state. Have adjusted lows downward with readings approaching 20 below in northern Aroostook County and subzero readings everywhere north of Bangor and Downeast. The steep low level inversion will slowly break Tuesday with warming southeast winds ahead of the occlusion. In general, models have trended colder and slower in the past 24 hours with increased likelihood of a secondary low developing in southern New England and tracking towards the Gulf of Maine. Expect most of the area to receive a quick burst of 2 to 3 inches of snow by Tuesday evening...and this will be the bulk of precip with this system. The exception will be the coast where onshore flow will warm the boundary layer with a resultant changeover to rain during the afternoon. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The rain/snow line will continue to push northward towards Bangor and through Hancock/Washington counties during Tuesday evening, but most precip will be over by midnight. Still looks like an advisory-level event. The passage of the warm occlusion will leave temperatures seasonably mild Wednesday morning with highs in the upper 20s north to mid 30s for Bangor and Ellsworth. An Arctic cold front crosses Wednesday afternoon. Could be some decent snow showers in the northern half of the area but will maintain chance PoPs for now. Arctic air will generate potential wind chill advisory conditions by later Wednesday night and Thursday will be the coldest day of the week by far with readings barely above zero in the Saint John Valley. Strong radiational cooling appears likely for Thursday night with subzero readings everywhere and some minus 20 readings possible in Aroostook County. A dry warm front will scour out the Arctic air later Friday. Saturday promises a return to above normal temps with sunshine. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... NEAR TERM: Occasional MVFR conditions are possible Downeast through early morning. Otherwise, VFR conditions are expected across the region into the early morning hours. MVFR/IFR conditions will then develop late with snow showers which will persist early Sunday. Conditions will improve to VFR levels Sunday afternoon. Low level wind shear is also a concern across the entire region overnight into Sunday morning with 35 to 40 knot southwest winds at 2000 feet. SHORT TERM: Saturday night into Tuesday midday...Predominately VFR Tuesday afternoon into Wednesday morning...IFR cigs and vis expected with tempo LIFR in snow. Slight chance of fzra for Bangor as well as LLWS Tuesday evening. Wednesday afternoon into Thursday...Predominately VFR outside snow showers and tempo MVFR cigs north of HUL. && .MARINE... NEAR TERM: A Small Craft Advisory remains in effect overnight through Sunday afternoon. Wind gusts could approach gale levels overnight. Visibilities will be reduced in snow showers later tonight through early Sunday. SHORT TERM: SCA conditions are expected later Tuesday into Thursday morning. A brief gale is possible Tuesday evening for the outer waters. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 5 PM EST Sunday for ANZ050>052. && $$ Near Term...Norcross/Hewitt Short Term...MCW Long Term...MCW Aviation...Norcross/MCW Marine...Norcross/MCW
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
529 PM CST Sat Feb 15 2020 .SHORT TERM... (Through Late Sunday Night) Issued at 324 PM CST Sat Feb 15 2020 A weak cold front will slowly move through the area tonight progressing into southern IL and southern MO by daybreak on Sunday. The current pre-frontal cloud band will slowly shift southeastward with the progression of the front tonight and there is some weak lift showing up later this evening into the overnight period from the St. Louis region and to the southwest within the axis of southwesterly low level flow. The RAP wants to generate some spotty light precipitation with weak lift. I am not sure there is deep enough moisture but its certainly worth a mention of sprinkles. The surface temperatures with any of this appear to be all above freezing. The front stalls to the south on Sunday as the weak post-frontal surface high/ridge slowly retreats to the east. There will be periods of clouds in the morning and then again increasing from the northwest in the afternoon. I am a little worried we may be too ambitious with high temperatures. I made a few small downward tweaks but nothing too major. Sunday night marks the beginning of a pattern change and large scale amplification across NOAM. The flow aloft across our area briefly becomes quasi-zonal ahead of the next progressive trof and associated cold front. Low level WAA and poleward moisture transport gets underway primarily overnight on Sunday into the early morning hours on Monday, and this maybe sufficient to support scattered light rain. The models suggest the most favorable area would be across southeast MO and southern IL. Surface temperatures are expected to be above freezing, so any rain should be all liquid. Glass .LONG TERM... (Monday through Next Saturday) Issued at 324 PM CST Sat Feb 15 2020 The coverage of rain is expected to ramp up through the day on Monday and into Monday evening in response to continued isentropic lift ahead of an advancing cold front, and increasing weak large scale lift associated with the migratory short wave trof driving the advancing cold front. Present indications are the rain will all be pre-frontal and will end west to east on Monday night as the cold front progresses quickly eastward with the advancing low amplitude upper trof. Given the precipitation is expected to be pre-frontal then there should be no threat of any wintry precipitation unless the distribution with respect to the front would change. Its worth mentioning the NAM wants to generate a band of snow within the cold air in its later time ranges late Tuesday into Tuesday night associated with a weak disturbance in the flow aloft and attendant mid level frontogenetic forcing. At this time its the sole deterministic model with this signal and the ensembles largely don`t support it at this time. Something worth watching however. Wednesday through Thursday Night look winter cold with below average temperatures as a large Arctic High builds southward into the region and dominates. There are some differences amongst the deterministic, ensembles, and MOS products on the strength of the cold airmass. The current forecast resides on the colder side of the overall guidance suite. Glass && .AVIATION... (For the 00z TAFs through 00z Sunday Evening) Issued at 509 PM CST Sat Feb 15 2020 A weak cold front will slowly push through the area overnight. Low VFR with patches of high MVFR will remain ahead of the cold front. These clouds shud continue to push south overnight. With areas behind the front clearing and winds becoming light, KUIN/KCOU may see fog developing late tonight as temps cool. Winds will eventually become SE to ESE late Sun afternoon, but remain light. SPECIFICS FOR KSTL/KSUS/KCPS: Low VFR with patches of high MVFR will remain ahead of an approaching cold front. A few sprinkles will be possible late this evening and overnight. Clouds shud clear out Sun morning with winds eventually become SE to ESE, remaining light. Tilly && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Norman OK
523 PM CST Sat Feb 15 2020 ...New AVIATION... .SHORT TERM... (This evening through Sunday) Issued at 218 PM CST Sat Feb 15 2020 The lee surface trough currently stretched across northwest Oklahoma will continue to slowly push southeastward, with the latest HRRR having it wash out near the I-44 corridor later this evening. Latest visible imagery showing stratus clouds across the Central High Plains spreading into northcentral Oklahoma, and expected to increase across much of our forecast area through this evening. However by early into mid Sunday morning, increasing surface moisture enhanced by light surface winds could result in fog developing. Already, moisture advection in the southerly winds ahead of the surface trough has increased dew point 3-5 degrees in the last 3 hours as per the Oklahoma Mesonet, and model trends continue the moisture advection well through Sunday. With the surface trough washing out and a lack of dry air behind it, we could see fog develop across our entire forecast area as our nocturnal temperatures fall. Much of the fog across the western one third of our forecast area would be more patchy, to more widespread and dense across portions of central and southeast Oklahoma. Expecting the fog to be dissipated by Sunday afternoon. && .LONG TERM... (Sunday night through next Friday) Issued at 253 PM CST Sat Feb 15 2020 For Sunday night, will need to watch for the potential of low clouds and fog again. With mainly light surface winds (east and southeast) and weak moisture advection over eastern Oklahoma, there will be some potential of fog. Above the surface, winds may be too strong for fog (mixing) and southwest to west in direction. North central Oklahoma may have light enough winds for some fog by Monday morning. Other areas may experience heavy dew. On Monday, a cold front will move across most of Oklahoma by late afternoon. The airmass behind the front will not be overly cold, but will keep temperatures across northern and central Oklahoma closer to Sunday`s high temperatures. A better shot of colder air will arrive Tuesday into Wednesday as cold high pressure builds southward. The source region of this air is brutally cold with temperatures around -45 to -50. The colder NAM keeps temperatures in 30s and lower 40s on Tuesday while other models are warmer. For now will nudge the blends cooler for Tuesday and Wednesday. As a shortwave trough shirts the area Wednesday into Wednesday night, some light precipitation may develop across far southern Oklahoma and western north Texas. A winter mix is possible. Will also keep in a chance of light snow across mainly northwestern and west central Oklahoma during this time. As cold surface high pressure builds east late Thursday into Friday, south winds will return with warmer temperatures. && .AVIATION... (00Z TAFS) Issued at 520 PM CST Sat Feb 15 2020 A weak wind shift (roughly KPNC-KJWG-KELK at 23Z) will wash out overnight, leaving light/variable or calm winds across most of the region. With increased moisture in place ahead of the wind shift, mostly clear skies, and light winds, fog is likely to occur. Some dense fog (visibility 1/4 mile or less) is possible over central and southeast Oklahoma. This area of fog will gradually lift and dissipate through the day tomorrow. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 38 61 43 63 / 0 0 10 10 Hobart OK 34 62 40 63 / 0 0 10 0 Wichita Falls TX 38 67 47 72 / 0 0 0 0 Gage OK 29 61 34 60 / 0 0 0 0 Ponca City OK 33 59 40 60 / 0 0 0 10 Durant OK 47 67 50 73 / 0 0 10 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ SHORT TERM...68 LONG TERM....06 AVIATION...23
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
700 PM EST Sat Feb 15 2020 .UPDATE... Latest RAP model shows nearly zonal flow aloft the Gulf region overnight while surface high pressure along the eastern seaboard extends into the Gulf of Mexico. Light northeasterly flow along with adequate low level moisture will support low clouds and patchy fog forming later tonight and continuing until mid Sun morning when the fog and clouds begin to burn off and lift. During Sun a short wave trough with a weak surface reflection tracks along the northern Gulf coast and crosses northern FL in the afternoon and evening. These feature will provide a slight chance to a chance of showers...reaching the Nature Coast early afternoon then spreading southward during the rest of the afternoon and evening. && .AVIATION... 16/00Z TAFs. Light NE flow along with adequate low level moisture will support late night CU/SC/ST with BR. Prevailing MVFR is expected AFT 06-08Z with PSBL TEMPO IFR/LIFR. BR and low clouds begin to mix out and lift 14-16Z with VFR through the end of the period. Winds become easterly in the morning then S to SW in the afternoon. && .MARINE... Prevailing northeast winds become easterly and southeasterly...but with an afternoon onshore component along the immediate 15 knots or less. Then toward the end of the week a cold front followed by high pressure will increase winds into the 15-20 knot range. && .Preliminary Point Temps/PoPs... TPA 61 78 65 79 / 0 10 20 10 FMY 64 82 65 83 / 0 10 20 10 GIF 60 83 63 84 / 0 10 20 20 SRQ 62 79 65 81 / 0 10 20 10 BKV 55 82 59 82 / 0 20 30 20 SPG 63 76 65 78 / 0 10 20 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION/MARINE...09/Rude UPPER AIR...04/Sobien DECISION SUPPORT...69/Close