Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/23/17


Area Forecast Discussion
National Weather Service Bismarck ND
929 PM CST Wed Nov 22 2017 .UPDATE... Issued at 924 PM CST Wed Nov 22 2017 Starting to see signs of dense fog forming in Saskatchewan that may work its way southeast along the edge of the cool air. The stretch from Burke southeast through northern Ward then north into Bottineau appears to be the best chance for dense fog. Will issue a special weather statement at this time then evaluate the need for any advisories later this evening in this area. UPDATE Issued at 616 PM CST Wed Nov 22 2017 Main concerns for this update include the stratus clouds sliding southeast through North Central North Dakota early this evening. Updated the sky condition to bring the clouds through a Minot to Jamestown later tonight but remain north of and east of a Bismarck to Williston line. Used the latest run of the HRRR for this. && .SHORT TERM...(This evening through Thursday) Issued at 227 PM CST Wed Nov 22 2017 Fog potential tonight into Thursday morning, and possible all time record highs for Thanksgiving highlight the short term forecast. The 19-20 UTC RAP/HRRR favor the potential development of fog across central North Dakota on the cool side of the low level baroclinic zone. Also added a mention of patchy fog for the Missouri River Valley above Lake Sakakawea and also most of northwest North Dakota. For Thanksgiving, record highs are forecast for many locations across western and central North Dakota with an anomalous warm airmass characterized by 850mb mean temperatures on the 12 UTC NAEFS around their 97.5-99th percentiles. With favorable southwesterly winds for warming, the top edge of the forecast envelope is favored for most areas for highs. The one caveat will be how long stratus and fog is able to hold across the north central through the James River Valley and its associated impact on forecast highs. Location....Forecast High...November 23.....Thanksgiving All Time Dickinson........71...........63 in 1984........65 in 1998 Williston........67...........56 in 2011........56 in 2002 Bismarck.........65...........62 in 2011........62 in 2002 Minot............61...........55 in 1942........57 in 2011 Jamestown........54...........59 in 1942........56 in 2011 .LONG TERM...(Thursday night through Wednesday) Issued at 227 PM CST Wed Nov 22 2017 A windy Friday and a potential rain/snow mix Monday into Tuesday highlight the extended forecast. The 12 UTC global suite is in agreement on a cold front propagating across western and central North Dakota Thursday night. Strong winds behind the cold front are favored, especially Friday morning and into the afternoon, when isallobaric forcing is greatest. 45-55kts to mix in the 800-850mb layer suggest that wind headlines are possible. However, the window for high wind warning criteria gusts is small. As has been the case, a few sites may sporadically reach warning criteria Friday morning with most sites in advisory criteria (sub 50kt gusts). For early next week, the 12 UTC suite diverges on how the wave arriving onto the Pacific Northwest coast Sunday into Monday evolves into the Northern and Central Plains Monday into Tuesday. While there is a chance for a rain and snow mix for western and central North Dakota, confidence in any one solution is low. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 616 PM CST Wed Nov 22 2017 Main hazards and impacts to aviation include MVFR to IFR conditions associated with a stratus deck and some fog forecast to move through a KMOT-KJMS line tonight. Conditions becoming VFR after 12-15Z Thursday. VFR at KISN-KDIK-KBIS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...PA LONG TERM...PA AVIATION...WAA
Area Forecast Discussion
National Weather Service Columbia SC
949 PM EST Wed Nov 22 2017 .SYNOPSIS... A series of low pressure systems will track from the Gulf of Mexico NE across Florida and offshore the Carolinas late Thursday through Friday night, providing variable cloudiness along with a slight chance of light rain, mainly in southern and eastern areas. A dry cold front will cross the region Saturday night, with high pressure building into the region for Sunday through Wednesday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Upper level trough axis will remain over the over the central Gulf States tonight with a weak surface boundary stretched from the western Atlantic Basin across FL and into the northern Gulf of Mexico. This will keep the forecast area between dry high pressure to the north and a weak low pressure in the northeastern Gulf of Mexico. Dewpoints currently vary greatly from the low teens in the Upstate to the 30s in the CLT and Pee Dee areas to the low 50s for the central Midlands through the CSRA. Overnight the low in the Gulf will move northeastward along the surface boundary spreading additional mid and upper level clouds into the area with some low clouds possible in the southern CSRA and southeastern Midlands toward daybreak. With the incoming clouds and dewpoints across the area overnight low temperatures will range from the mid 30s along the NC border to the mid 40s in the southern Midlands and CSRA. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... An upper level trough extending into the Gulf of Mexico will develop low pressure along a remnant frontal boundary. The low will track NE across FL through Friday night and likely remain off the eastern coastline. Although the deterministic GFS and ECMWF keep the area dry, there is considerable spread in the ensemble forecasts for the southern and eastern forecast area. Suggesting there is a slight chance for rain in these areas both Thursday and Friday. The NAM appears too aggressive in developing the low resulting in widespread rain across the entire area. There will be more clouds Thursday than previous days contributing to cooler daytime temperatures. Expect highs in the mid to upper 50s on Thursday and around 60 degrees Friday. The drier air that will move into the FA will also support cooler than normal nighttime temperatures, especially in the northern FA where there will be less cloud cover. Temperatures Thursday night will be from the lower 30s to the north to around 40 degrees in the southern FA. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Another upper level trough will dig into the Southeast Saturday bringing a cold front with limited moisture through the region. High pressure and drier air will work its way into the region behind the front and will be over the mid-Atlantic on Monday. The coolest temperatures will be on Monday and Tuesday morning. High pressure will begin to move off the coastline Tuesday as southerly flow develops. This will lead to temperatures warming to above normal by the end of the period. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Expect VFR conditions during the 24-hour TAF period. The terminals will be between the pressure ridge west of the Southern Appalachians and front just off the Southeast Coast. Deeper moisture along the front will stay east of the terminals. Model time-height displays depict a shear zone and moisture around 4000 feet during much of the period. Much of the NAM and GFS MOS have a VFR ceiling at times. A dry near-surface layer because of the flow from the ridging to the west plus a little mixing associated with a weak low-level jet should help prevent fog during the early morning hours as indicated by the GFS and NAM MOS, HRRR and SREF guidance. Followed the GFS and NAM MOS and forecasted light north to northeast wind. EXTENDED AVIATION OUTLOOK...A frontal zone near the coast with a series of low pressure centers moving northeastward may help support MVFR or IFR conditions at times Friday but confidence is low at this time. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion
National Weather Service Grand Forks ND
649 PM CST Wed Nov 22 2017 .UPDATE... Issued at 645 PM CST Wed Nov 22 2017 A band of low clouds will persist a bit longer into the evening hours across northeast ND and Northwest MN, and the forecast has been adjusted to accommodate it. Otherwise, no other forecast update needed for this early evening. An updated Aviation Discussion is attached below. && .SHORT TERM...(This evening through Thursday) Issued at 326 PM CST Wed Nov 22 2017 Clouds and their effect on temps will be the main challenge for the period. Northwesterly flow aloft continues across the region, with one weak shortwave moving off into Ontario and helping push the trough through the Dakotas. There will continue to be some very light snow and even some mixed precipitation for a brief period on the backside of the band through this evening, but the precip should rapidly taper off after sunset. With the surface trough axis moving east high pressure will begin to build down into ND this evening. Think there could be some brief clearing in some areas behind the low, but the HRRR and RAP both develops some stratus and maybe fog along the baroclinic zone. There were plenty of clouds under the surface high this morning in Canada, although not much fog. Given the time of year it is possible we will see more cloud cover than expected overnight, with teens to low 20s for lows. Tomorrow`s temperatures will be highly dependent on what happens with clouds. Warm air advection starts early, with both 925mb and 850mb temps into the low teens across our southwestern counties. The question will be if any of that gets mixed down or if we just end up with a huge inversion. The next surface trough will be approaching from the west, so central ND and even our far western counties could see some southwesterly winds that will help get clouds out and allow temps to warm. Have some highs approaching 50 in the southwest, but further north and east we will still be in the cooler air and clouds. Still have temps fairly warm in comparison to recent days, but staying in the 30s. .LONG TERM...(Thursday night through Wednesday) Issued at 326 PM CST Wed Nov 22 2017 Will see a mainly progressive pattern in the extended period, with generally near to above normal temperatures and chances for precipitation. Thursday night and Friday will be much warmer as the upper level ridge builds over the region. Will see strong warm advection at the 850 hPa surface with temperatures forecast to reach from 12C to 14C, which translates to high temperatures near 40 in the north to low 50s in the south. Residual snowpack in the north may affect temperatures a bit but still looking at above normal values for this time of year. The system crossing the area on Friday will trigger some precipitation, mainly in conjunction with the trailing cold front, with the main precip type in the form of rain. Some light snow can be anticipated as the system exits, with the cold air intrusion changing the precip type to light snow. As the low strengthens across southern Ontario, look for northwest winds to increase and gusts should push into the 30-45 mph range. The weekend will be drier as high pressure settles in and temperatures can be expected to be near normal. As the surface high retreats, return flow will help bump temperatures again for Sunday into Monday. By Monday night, the upper pattern shifts more to a split flow regime, with the northern branch across southern Canada and the southern branch carving a deep trof over the intermountain west. Looking for a wave to develop in the central plains along the southern branch, with a chance for light precipitation in the southern forecast area by Tuesday morning. Otherwise, expect mainly dry conditions beyond Tuesday through the end of the period, with temperatures cooling slightly. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 646 PM CST Wed Nov 22 2017 Areas of MVFR CIGS will persist through 04z in northeast ND and far northwest MN. Otherwise expect VFR conditions with winds becoming light and variable overnight. Expect light south winds on Wednesday with patchy VFR clouds. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Gust SHORT TERM...JR LONG TERM...Hopkins AVIATION...Gust
Area Forecast Discussion
National Weather Service Marquette MI
625 PM EST Wed Nov 22 2017 .SHORT TERM...(This evening through Thursday) Issued at 403 PM EST WED NOV 22 2017 WV imagery and RAP analysis indicated a mid/upper level ridge from the sw CONUS into BC/Alberta and a trough over the east resulting in nw flow through the nrn Great Lakes. At the surface, sw flow was increasing as a ridge moves east from the cntrl Great Lakes and a trough edges through the plains. The broad WAA pattern supported some light snow from ern MN into wrn WI with the lowest vsby only to around 3sm. Radar returns into the wrn cwa remained aloft with only mid clouds observed in the very dry airmass, per 12z KMPX/KGRB soundings. Tonight, Although the stronger isentropic lift and greater moisture slide mainly south of the cwa per radar/satellite trends, some light snow may be possible over the far west early this evening. As the sw winds over Lake Superior veer wrly overnight some lake enhanced snow may also develop into the Keweenaw. However, instability will be limited with 850 mb temps only to around -8C. Thursday, winds will veer enough to bring any light LES into the far ne cwa east of Munising. Otherwise, a sfc ridg building into the area will bring some clearing with some sunshine especially over the south. This will help push temps into the mid to upper 30s. .LONG TERM...(Thursday night through Wednesday) Issued at 305 PM EST WED NOV 22 2017 ...Up and down temperatures into next week with brief shot of lake effect on Sat... Upper air pattern late this week features trough over western Canada sliding toward the Great Lakes while ridge builds over western Conus and western Canada. Associated sfc low with the advancing trough will deepen to 980-985mb as it reaches central Manitoba on Fri morning. Warm air moving in ahead of the low along with some mid- level moisture could support some light precipitation late Thu night into Fri morning, especially north and east where sufficient saturation for precip looks like better bet. Looks like there is enough warm air sfc and aloft to keep ptype rain if it occurs. Fri will be breezy (SW winds 20-30 mph with higher gusts possible) with temperatures rising above normal (h85 temps upwards of +10c supporting highs well into the 40s some areas) as Upper Lakes is within warm sector of the deep sfc low crossing into northern Ontario. Could be even warmer if there were not as many clouds around. Day will be mostly cloudy to start with plenty of mid clouds, then shortwave driving in from northwest through the day will eventually spread rain showers back over the forecast area through the aftn. Any precip should stay rain until later Fri night when it changes back to snow as colder air moves back in behind the cold front tied to the low. Not expecting widespread snow though as most of heavier precip with the system will be out of the area by time change over occurs. On Sat, polar jet digs across Lk Superior and Upper Michigan. Upper trough will deepen over Great Lakes and colder air (H85 temps as low as -13c) will move across the region. After the warmer temps on Fri, high temps on Sat will be in the 20s west to low 30s east. Temps may fall through the day in some areas. WNW-NW winds will result in lake effect snow. Snow showers could be heavy at times as cold air first charges in, but lake effect should diminish by Sat night as synoptic moisture exits and inversions up to 6-7kft fall with arrival of anticyclonic flow as high pressure builds from central Canada to the Upper Great Lakes and middle Mississippi River Valley. Overall the snow amounts from the lake effect should stay in check with limited synoptic support. Bigger impact could be from reduced vsby at times in snow/blowing snow as northwest winds gust to 30-40 mph. Overall could see similar conditions on Sat to what just occurred on Tue. Lake effect diminishes Sat night into Sun, hanging on longest over east forecast area. Ridging then builds in sfc-aloft by Mon. Temps should stay in the 30s on Sun, but then could rise well into the 40s on Mon. Signal in some of the guidance that with main trough/jet streak west and north and sfc low well to the north, Mon could end up being fairly sunny. If that is case, which is certainly tricky this time of year, temps in some areas could reach 50F. Following the warm up, latest GFS quite aggressive in return to upper troughing/cold air mid week while ECMWF/ensembles and GEM keep it warmer. GFS not agreeing well with NAEFS ensembles either. Probably will see temps cool back mid to late next week but probably not to the degree that the latest GFS is showing. Return to cooler weather could come with a storm system, but per ensembles, probably not to the extent 12z ECMWF shows with strong system over the Great Lakes late next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 613 PM EST WED NOV 22 2017 Mid-level clouds will give way to -sn/flurries this evening/overnight at KIWD and KCMX at then prevail with the potential for light snow or flurries at KIWD and KCMX late this afternoon and evening. Winds turning to an onshore westerly direction at KCMX will bring cigs down to MVFR overnight but expect improvement to VFR Thu afternoon. Otherwise at KIWD and KSAW expect VFR conditions throughout the forecast period. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 403 PM EST WED NOV 22 2017 SW winds up to 30 knots will veer to the west late tonight into Thursday and then will back to the south on Friday. Another strong low pressure system will then bring the potential for northwest gales of 35 to 40 knots Friday night into Saturday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... Gale Watch from late Thursday night through Friday evening for LMZ248-250. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...Voss MARINE...JLB
Area Forecast Discussion
National Weather Service Pocatello ID
205 PM MST Wed Nov 22 2017 .SHORT TERM...Tonight through Saturday afternoon. Snow levels remain elevated around 9000 feet of elevation through Thursday evening, then lower to about 6000 feet on Friday with passage of a disturbance and surface cold front. Snow accumulation in the mountains limited to 1 to 2 inches with 3 inches possible on the higher peaks. Patchy fog and low stratus can also be expected in the Upper Snake Highlands, including Raynolds Pass. This alone does not pose travel difficulties, but winds of 15 to 25 mph are expected in the Snake Plain both Thursday night and Friday. The strongest winds will probably be Friday, and may reach 20 to 30 mph. Gusty cross winds will develop on US 26 and 30, also SH 33. RS .LONG TERM...Saturday night through next Wednesday. The latter half of this weekend will see the upper ridge shifting to the east and a return to a rather active period through Monday night, possibly Tuesday. GFS continues to support a more progressive pattern than the ECMWF. Thus, the timing of many things remains uncertain, the biggest of which will be the changeover from rain to snow. GFS solution would put a slow-down to the Monday morning commute, while the ECMWF snow levels support rain until the Monday afternoon commute. We are generally looking for about 7 to 10 inches of snow in the Central Mountains for the duration of the storm Sunday night through Monday night. Snow amounts seem to taper off shortly after the snow levels drop to valley floors, but may still impede travel in the passes. Light snow amounts are possible in the Snake Plain, but some of the benches could see 1 to 2 inches. Strong winds associated with the surface front will become apparent on Monday as well with winds 25 to 30 mph across the Snake Plain and South Central Highlands, giving a strong crosswind component along I-84 and I-15. Extended MOS guidance suggests even stronger winds, approaching warning levels. Tuesday and Wednesday look cool, but much drier. Hinsberger && .AVIATION...Mid and high clouds are streaming through the upper ridge across the West today. Upstream observations indicate cloud bases around 8500 to 11000 ft, though forecast BUFKIT soundings indicate drying in the mid-levels, but support a cirrus layer through tomorrow morning. Soundings also indicate surface layers nearing saturation, which may promote fog development. NAM MOS guidance shows greater fog potential for KIDA. KDIJ remains a challenge with the ceiling lingering around 2000 ft. HRRR sounding supports improvements there around 22Z, but NAM3km holds off until around 04Z-05Z. Weighted forecast closer to HRRR. Hinsberger && .PIH WATCHES/WARNINGS/ADVISORIES...None. && $$
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
708 PM EST Wed Nov 22 2017 .UPDATE (Overnight through Thanksgiving Day)... Complex forecast scenario unfolding during the next 24-36 hours as deep layer and amplified troughing evolves eastward across the Gulf of Mexico toward the region. The main trough axis stays well to our west through Thanksgiving day, however, periodic shortwave impulses ejecting around the trough through the eastern Gulf of Mexico will be responsible for the timing and location of predicted bands of rain moving ashore. The radar is actually quite active this evening. First area is actually some sea-breeze convection (is this November?) to the south of I-4 that will be dissipating during the next couple of hours. The second area of rain is offshore across the eastern Gulf of Mexico. This area of rain is associated with the first of these lead shortwave impulses to approach our coast...coupled with semi-favorable upper jet entrance region dynamics. This shortwave is shown by latest RAP is shear out as it moves across northern Florida later this evening and becomes increasingly separated from the parent trough. With this in mind...agree with the RAP/HRRR trends toward this band weakening and becoming lighter/more broken in the next few hours as it nears the coast. In fact, very recent radar trends suggest this process may already have begun. Therefore, although a few light showers can not be ruled out near the coast before midnight, they should not have a large impact to any outdoor activities. After midnight...and especially toward dawn, evolution eastward of the main trough axis into the central Gulf of mexico and additional leading shortwave impulses should help to organize an area of surface cyclogenesis over the eastern Gulf of Mexico. Increasing low level focus associated with this feature underneath broad synoptic forcing/Qvector convergence ahead of the main trough should support more rounds of showers/embedded storms developing over the eastern Gulf of Mexico. It will be these bands that are expected to move ashore during Thursday morning. The exact track of the low varies from one NWP member to the next, but a general consensus brings the circulation slowly toward the Tampa Bay area or slightly to the north by the evening hours. This track would suggest the best frontogenetic forcing for steadier shower activity will be from near the I-4 corridor northward. One of the forecast uncertainties is how defined these frontogenesis bands are north of the low track during the day. If they are well-defined and the low passes just north of Tampa Bay area...then the steadier shower potential would tend to shift north of I-4. However, with only a broad cyclone, these types of predictions are very difficult more than a few hours in advance, and this point is strengthened by the differing position of QPF maxes from run to run with many of the NWP members. Given all that was said above, certainly not saying there will not be showers/storms further south, however, the warmer sector of the cyclone will tend to support less organized and more scattered activity. && .AVIATION (23/00z THROUGH 24/06z)... Low pressure will slowly approach the Florida west coast through the period. Cigs will generally lower through the overnight in advance of this system...with increasing potential for periodic showers moving ashore from KSRQ northward through Tampa Bay. Expect periods of MVFR cigs for all terminals after midnight...with patchy fog also for KLAL/KPGD. Several rounds of showers through Thanksgiving day...with rain chances and shower duration greatest for terminals along I-4 corridor. Expect at least periods of MVFR cigs/vis to continue through the morning hours...with shower potential lingering through the end of the TAF period. && Previous Discussion... .SHORT TERM (Tonight through Thursday)... Mid/upper level trough will continue to amplify over the Gulf of Mexico helping to develop an area of low pressure over the central Gulf of Mexico. This low will drift east northeast along the stalled boundary that extends into north Florida on Thursday. Deep moisture and forcing will move into the region late tonight and Thursday leading to increasing clouds and rain chances from northwest to southeast during the period. Mid-level temperatures will be cool enough, -10C to -12C, to allow for enough instability for a few thunderstorms to develop. Overall it looks rather cloudy and damp for Thanksgiving Day, especially across northern and central Florida where the rain should arrive late tonight/Thursday morning, while further to the south and east over the southern interior and southwest Florida most of the rain will not arrive until midday/afternoon. Temperatures tonight will remain in the 60s with highs on Thursday only climbing to near 70 northern Nature Coast to near 80 degrees over the southern interior and southwest Florida. .MID TERM/LONG TERM (Thursday Night-Wednesday)... A closed upper low sits over northern Quebec with deep troughing extending south along the east coast into the central Gulf of Mexico. Not a lot of change is expected through the period as the trough moves slowly eastward into the western Atlantic by the beginning of next week. Upper ridging moves in behind this trough and extends from the Gulf of Mexico over the southeast U.S. On the surface, models are in good agreement with a developing area of low pressure in the Gulf of Mexico that will move eastward along a frontal boundary to influence the weather late Thursday into Friday. High rain chances (50-70% POPs) can be expected over the region as this low moves across Florida. High pressure builds into the area behind this low for the remainder of the period bringing clearing conditions to the region. Temperatures will be slightly below average through the middle of next week as the high pressure filters in cooler air in the wake of the low pressure and frontal boundary. .MARINE... A developing area of low pressure in the central Gulf of Mexico will move east northeast across Florida Thursday into Friday. This will bring an increase in winds over the Gulf waters, mainly from Tampa Bay north tonight and Friday, with periods of cautionary level winds possible. Conditions will improve Friday night into Saturday as high pressure builds back in over the Gulf. .FIRE WEATHER... Relative humidity values will remain above critical levels with no fire weather issues expected through the week as plentiful moisture remains across the region. Some patchy fog will be possible late tonight into early Thursday, especially across southwest Florida. && .Preliminary Point Temps/PoPs... TPA 67 75 66 75 / 60 90 70 60 FMY 67 80 67 77 / 20 70 40 50 GIF 64 77 64 75 / 40 80 60 50 SRQ 66 77 65 74 / 50 80 60 60 BKV 63 74 61 73 / 80 90 70 60 SPG 66 75 65 74 / 70 90 60 60 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION...14/Mroczka Previous Discussion...Close/Wynn