Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/30/21

Area Forecast Discussion
National Weather Service Dodge City KS
555 PM CST Fri Jan 29 2021 ...Updated Aviation... .SHORT TERM...(This evening through Saturday) Issued at 331 PM CST Fri Jan 29 2021 The boundary layer is showing southerly flow at around +14 to +16 deg C at 850 mb impinging on a very cold surface layer over northern Kansas, where a stationary front is straddled east to west just north of the I-70 corridor. The widespread freezing fog has remained north the Hays vicinity though the early afternoon and temperatures elsewhere have been slow to respond given the increasing/extensive cloud cover over the area. The HRRR and RAP13km/HiResARW models all keep the redevelopment of dense fog north of I-70. However GFSLAmp indicated high probability for VLIFR type ceilings to rapidly develop around 09Z as the rain and possibly brief freezing rain lifts rapidly north into central Kansas before dawn. Basically, we do not anticipate high probability of needing a dense fog advisory at this time, however if conditions deteriorate late this evening, those areas along and north of I-70 would be the prime areas. .LONG TERM...(Saturday night through Friday) Issued at 331 PM CST Fri Jan 29 2021 Warm conveyer belt type surge of lift and moisture will spread over roughly the southeast third of the area, with reasonably high confidence. Surface dew points surge into the 40s. Far southeast sections of the area should see at quarter inch of rain or possibly much higher. The NAM12 prints out areas of minimal, but still some convective precipitation inferring some instability present southeast of Dodge City. The period of rain will be brief as the low pressure moves out quickly and deep northwest flow takes over the rest of the afternoon. Strong 30-35 knot winds in the boundary layer should result in very strong gusts through the daytime hours, and even "weaker" still windy conditions going into the evening hours over western Kansas. Right now the GFSLAMP guidance is showing strong wind speeds around 30-33 knots sustained in the early afternoon Saturday across the most windy region (GCK/LBL), with gusts around 40 knots. Model output from the IEM meteograms generator for momentum transfer indicate potential for 50 knot gusts for a couple of hours, but many more remain well below the 50 knot gust threshold for High Wind. The extended period still looks active as the westerlies buckle to a longwave ridge over the Great Plains Monday and Tuesday with the high probability of a negatively tilted synoptic scale cyclone impacting the central plains by mid to late week (Wednesday night into Thursday night). At this time, the consensus of ECMWF/GFS would place best chances for the heavy precipitation axis somewhere from western Iowa into northwestern Kansas. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 552 PM CST Fri Jan 29 2021 VFR flying conditions are expected at all terminals for roughly the first 12 hours of this TAF period. Around 12Z tomorrow, low cigs and associated rain will move in from the south bringing DDC, GCK, and HYS into MVFR/IFR through the early afternoon. LBL will likely avoid a drop in flight category, but a glancing blow of MVFR cannot be ruled out. There is also a slight chance of freezing rain/sleet near HYS in the late morning and early afternoon, but confidence is too low to mention in the TAFs. Shortly before sunset, all precipitation is expected to move out of southwest Kansas, and all terminals should return to VFR. && .PRELIMINARY POINT TEMPS/POPS... DDC 38 50 29 49 / 40 90 0 0 GCK 32 50 27 49 / 20 40 0 0 EHA 36 57 29 53 / 10 10 0 0 LBL 40 57 28 53 / 30 20 0 0 HYS 30 40 26 42 / 20 50 0 0 P28 44 55 30 49 / 100 90 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Springer
National Weather Service Hastings NE
541 PM CST Fri Jan 29 2021 ...AVIATION UPDATE... .DISCUSSION...(This evening through Friday) Issued at 351 PM CST Fri Jan 29 2021 Main concerns are dense fog tonight, wintry mix late tonight through Saturday evening, and blowing snow potential from strong north/northwest winds Saturday afternoon/night. The last of the fog finally lifted, or at least improved in visibility in our west, no thanks to the low sun angle of January. The HRRR did a pretty good job with this compared to other models/guidance. With conditions similar tonight and HRRR indicating a return of fog from generally west to east, I have high confidence of dense fog returning. Look for some light icing from freezing fog, which will possibly impact roadways and make them slick. Went with CONSRaw for lows tonight considering the cloudy conditions and light fog developing, favoring a warmer solution. Went with CONSShort/NBM temp combo for highs Saturday. Adding insult to injury will be the potential for wintry mix/light freezing drizzle with a stubborn dry mid-level forecast quite consistently. Both the HRRR and NAM advertise the potential of freezing drizzle through Saturday evening, save the short period Saturday afternoon when we may be just above freezing. Models have generally held ground or shifted southeast with the precip band of a low moving across Kansas, with the noticeable exception of the GFS ensembles nudging a bit northwest over the past few runs. The NAM has even been trending southeast with precip. Taking this all into account, I backed off QPF, shifting it southeast. Ice accumulation, if any, would be light and same for any skiff of snow that may occur. Still could be a bit of blowing snow, especially farther northwest where it would be less likely to get freezing drizzle to tamp down blowing snow. since we don`t have at least likely POPs for Saturday, I opted away from issuing a winter weather advisory. I did highlight slick conditions from freezing fog development tonight/Saturday. In reality, it may be from both freezing fog and freezing drizzle. The importance would be that folks know that slick conditions are definitely possible. Focused less for later in the forecast, but still on track for moderating temps early next week and a significant system for Wednesday night/Thursday, and could very well be a larger weather maker than what we are getting tonight through Saturday night. .AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Saturday) Issued at 1158 AM CST Fri Jan 29 2021 Biggest concerns are visibility and fog. Fog has held on longer than earlier forecast and may stick around for at least a short while this afternoon before returning. Most models and satellite trends indicate that we will get a temporary reprieve from the fog, especially in the more eastern terminal of KGRI. Fog is almost a sure thing to come back and develop tonight along with LIFR ceilings. Confidence is quite high in fog redevelopment and there is widespread agreement among numerical models. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday) Issued at 533 PM CST Fri Jan 29 2021 Another foggy night ahead, looking very similar to today/yesterday. Cigs are expected to remain rather low...mostly IFR and LIFR though there may be the occasional pocket of MVFR. However, this will likely be inconsequential with dense fog expected to develop over the next several hours (with visibilities expected to be generally around 1/4 mi or less) which will likely persist through most of the day tomorrow. During the daylight hours though, visibilities may improve slightly to around 1-2 mi. Slight precip chances exist tomorrow afternoon, mainly for KGRI, and both terminals will likely see blowing snow later in the afternoon tomorrow and into the evening hours, with wind speeds expected to pick up to around 20kts with gusts to around 25-30kts. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Dense Fog Advisory from 9 PM this evening to noon CST Saturday for NEZ039>041-046>049-060>064-072>077-082>087. KS...Dense Fog Advisory from 9 PM this evening to noon CST Saturday for KSZ005>007-017>019. && $$ DISCUSSION...Heinlein AVIATION...Shawkey
Area Forecast Discussion
National Weather Service Jacksonville FL
820 PM EST Fri Jan 29 2021 .UPDATE... Forecast on track rest of tonight with light winds and clear skies enabling excellent radiational cooling. Temps expected to bottom out in the lower to mid 30s inland, with mid 30s to around the lower 40s toward the coast. In addition to frost potential inland areas, very patchy fog will be possible, mainly over inland northeast FL, due to the influx of some low level moisture from the east to northeast flow today. This is supported by HRRR and SREF guidance. .MARINE... Just slight changes to the forecast to make wave dominant period long period swells around 12 seconds rest of tonight, as wave models about 12 hours behind on the east-northeast swell train. Seas nearshore a little low some bumped up slightly. Otherwise, no change to headline offshore. && .PREV DISCUSSION [639 PM EST]... .NEAR TERM [Tonight Through Saturday]... High pressure extending over the Ohio and Tennessee Valleys will weaken slightly and slowly shift east tonight and tomorrow, which will keep conditions dry. Surface high pressure to our north will result in light northeasterly winds tonight that will shift to be easterly tomorrow as the high shifts to our northeast. Overnight, winds will be calm and skies will be clear, resulting in strong radiative cooling and cold temperatures. Low temperatures tonight will be in the low-to-mid 30s in SE GA and mid-to-upper 30s in NE FL. Low temperatures will be slightly warmer in the lower 40s in north central FL and at the coasts. Frost is expected again tonight at inland locations. Saturday will be warmer than today with high temperatures in the lower 60s in SE GA and mid-to-upper 60s in NE FL. Cloud cover will begin to build throughout the day ahead an approaching low pressure system moving east across the Midwest. .SHORT TERM [Saturday Night Through Tuesday]... High pressure will be northeast of the region Saturday night, then to the east on Sunday. A cold front will move southeast into western counties late in the day Sunday, with much of the precipitation expected to be on a prefrontal trough just ahead of the front itself. The front will push to the southeast of the forecast area Sunday night. Saturday night is expected to remain dry across region, with much of Sunday day light hours dry as well for NE FL. For far inland SE GA counties a line of showers, with embedded thunderstorms to move in early afternoon. This area will move across SE GA and Suwannee valley through the remainder of the afternoon hours, then into coastal NE FL Sunday evening. Temperatures will have a chance to surge east of this line along with dewpoints, especially for NE FL, so potential for a few strong storms exist. This potential will exist in SE GA as well due to better upper support, despite the cooler temperatures. Region will be between departing low to the northeast and building high from the west Sunday night through Monday, as an upper trough pivots southeast into area. Cold advection expected during this period. Due to pressure gradient winds will remain elevated Sunday night and become breezy during the day Monday. The upper trough will help keep clouds across area, despite building surface high pressure. The combination of winds and clouds will help keep temperatures from falling off too fast for Sunday night. The cold advection and cloud cover will yield a below normal day for Monday. The upper trough will push toward the east Monday night as surface ridge builds closer. This will yield decreasing clouds through the night, with temperatures into the lower 30s inland. The continued pressure gradient is expected to keep winds stirring enough to limit frost potential though. Sunshine is expected for Tuesday, but the cooler than normal airmass will remain in place. .LONG TERM [Tuesday Night Through Friday]... The surface high will build overhead Tuesday night through Wednesday morning, then toward the east late Wednesday. This pattern will provide clear skies and fairly light winds. Tuesday night will likely be the coldest night of the week, with a fairly widespread frost and freeze potential away from coast. A sunny day is expected for Wednesday, with temperatures rising closer to seasonal averages as the afternoon flow trends more from the south due to position of the high. The high will build toward the east northeast Wednesday night through Thursday. This will yield an increasingly warm southerly flow. As the high moves further to the east Thursday night, and a cold front approaches from the west, moisture will increase across the area. Models do diverge in timing of this frontal system. GFS brings front in later in the day Friday, while the ECMWF keeps it to the west through this period. Given expected strength of the high, the slower progression to the low makes sense, so will trend with toward the drier solution late in this period. This will keep the warm southerly flow going into Friday, with temperatures well above normal. .AVIATION... [Through 00Z Sunday] Light to calm winds and nearly clear skies will prevail through Saturday morning. Winds will become easterly Saturday mid-morning, then east-southeast Saturday afternoon near 10 knots. Increasing onshore flow will lead to more cumulus/cloud coverage during the aftn. SREF guidance suggesting MVFR ceilings for Saturday around and after 18Z, but due to chances being below 40 percent, it was not placed in the TAFs. .MARINE... High pressure will build to the northeast of the region Tonight through Saturday night. The high will build more toward the east Sunday, as a cold front approaches from the west. The cold front will move southeast across area Sunday into Sunday night. On Monday the region will be between low pressure to the northeast and high pressure building to the northwest. The high will continue to build from the west Monday night through Tuesday, then overhead for Wednesday. The high will build toward the east Thursday, with a cold front approaching from the west Friday. Rip Currents: SE GA Moderate through Saturday NE FL Trending toward High for Saturday && .PRELIMINARY POINT TEMPS/POPS... AMG 32 62 47 68 45 / 0 0 20 80 40 SSI 39 59 52 69 48 / 0 0 10 50 70 JAX 36 64 52 74 48 / 0 0 10 20 60 SGJ 43 64 54 74 50 / 0 10 0 10 60 GNV 37 68 50 74 48 / 0 0 0 20 70 OCF 38 70 51 76 50 / 0 0 0 10 70 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. &&
National Weather Service Jackson KY
1025 PM EST Fri Jan 29 2021 .UPDATE... Issued at 1025 PM EST FRI JAN 29 2021 Mostly clear skies, light winds, and dry dewpoints are leading to a good night of radiational cooling with a small ridge to valley temperature split opening up. This will be mitigated somewhat by high clouds moving in from the northwest later tonight. The current forecast has this all well in hand and have mainly just touched up the T and Td grids per the latest obs and trends. These freshened grids have been sent to the NDFD and web servers. UPDATE Issued at 645 PM EST FRI JAN 29 2021 23z sfc analysis shows high pressure over the Ohio Valley and keeping skies mostly clear and winds light this evening. Temperatures are running in the upper 20s to lower 30s while dewpoints are mostly in the mid teens. Have updated the grids mainly to add in the current obs and trends for the T/Td ones. These updates have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Saturday night) Issued at 425 PM EST FRI JAN 29 2021 Late this afternoon an upper level low was centered southeast of Cape Cod while an upper level ridge extended from Mexico north through the central Conus. Northwest flow aloft is currently in place across eastern KY at this time between the trough to the east and the ridge axis to the west. Further west, a trough was moving across the southwestern Conus. Mid level clouds had been rather persistent near and just east of the northern and eastern fringes of eastern KY, but has begun to diminish. At the surface, an area of high pressure a ridge of high pressure extends from the Great Lakes across the OH Valley and into the southeast Conus. With the airmass starting to moderate, temperatures outside of the high terrain reached the 30s. The airmass remains dry, however, with dewpoints ranging through the teens. Tonight, the trough to the northeast and east of the area is expected to begin to shift east of the area while the axis of the upper level moves into the eastern Conus. At the same time, the trough moving across the southwestern Conus will work across the Four Corners and reach the plains late. Sfc low pressure should begin to develop/organize to the lee of the Rockies over the high Plains in the western OK panhandle vicinity in advance of this. The axis of the upper level ridge is expected to move east of the area during the day on Thursday while the trough closing off to an upper level low moves quickly across the Plains and nears the mid MS Valley Saturday evening. The upper level low should track into the northern IL vicinity by the end of the period. Meanwhile, the sfc low is expected to track into western MO early on Saturday evening and reach near the confluence of the OH and MS Rivers late in the period. Isentropic lift associated with a warm front and forcing in advance of the upper level low/trough and deepening sfc low is expected to lead to increasing as well as thickening and lowering clouds on Saturday, particularly from late in the morning through the afternoon. Moistening up from the top down appears likely despite a dry airmass to begin the day and measurable precipitation may fall during the evening as the warm front lifts northeast across the area. The initial dry air and associated wetbulbing of the column may result in a mix of rain and snow with this band lifting northeast. As the lower levels continue to saturate a brief window where freezing rain may be possible if temperatures reach the freezing mark cannot be ruled out along the northern and eastern fringes of the area in the higher terrain generally above 2500 feet. These highest elevations could also experience snow on the leading edge of the main band of precipitation associated with this low that arrives later in the evening and into the overnight. Continued warm air advection should lead to all rain in the highest elevations toward dawn. The 18Z HRRR appears holds onto snow about as late as any guidance and has a few inches on the top of Black Mountain. The 12Z HREF PMM has much less for the top of Black Mountain. Overall, opted to go with a compromise among the guidance, allowing for wetbulbing of the lower levels to lead to a rain and snow mix generally over the north and east with the initial band in the late afternoon and evening as well as with the leading edge of the main band of precipitation late in the evening into the early portion of the overnight. Most locations should be too warm not experience any accumulation, but some light accumulations cannot be ruled out north of the Mtn Pkwy. especially near and north of I 64 as well as in the elevations above 2500 feet. Sfc and upper level ridging shifting across the area will set the stage for the eastern and northeastern valleys to be the coldest tonight, with readings as low as the mid teens anticipated there. Ahead of the increase in clouds on Saturday, temperatures should moderate to the 40s outside of the highest terrain. How heavy the precipitation is with the leading edge is uncertain and this will modulate how much wetbulbing occurs late in the afternoon and evening, leading to uncertainty in hourly temperatures there. .LONG TERM...(Sunday through Friday) Issued at 514 PM EST FRI JAN 29 2021 The long-term period begins Sunday morning with troughing over the heart of the nation and its parent cutoff upper level low centered over northern Illinois. A building upper level ridge will be situated well to our west along the Continental Divide. At the surface, an ~1000mb surface low will be found over southern Illinois. Multiple fronts and troughs will originate from this surface low, the first of which will be a warm front along the Ohio River. This warm front will be responsible for a period of rain and mixed precipitation Saturday night and early Sunday morning. Another cold occluding front will extend southward from the low into Tennessee. A secondary cold front and multiple surface troughs will be radiating outward like spokes along the western and northern portions of the low. 12z Sunday-00z Wednesday... Rain showers, associated with the leading warm front, should taper off for most locations Sunday morning as a dry slot wraps in around the southern side of the storm system. GFS and HRRR model soundings suggest that the clouds should thin enough for at least partial sunshine to break out during the morning and early afternoon, particularly south of the Mountain Parkway. The clouds and a few spotty showers will likely remain more stubborn north of the Mountain Parkway due to the proximity of the surface low passing along the Ohio River. Temperatures should be quite mild, warming into low to mid 50s south while northern locations stuck under the clouds will probably stay in the 40s. Late in the day, the low`s occluded front will push from west to east across the forecast area. Model soundings appear to supportive of a broken line of shallow convection with this front, but equilibrium levels warmer than -10C would not be supportive of thunder. During the overnight on Sunday night, the filling surface low will move to near Huntington, WV while a new triple point low takes shape along the North Carolina Coast. As this occurs, a secondary surface cold front will pivot around the backside of the filling low turning winds more northerly over the Commonwealth which will usher in colder air and wrap-around moisture. At the same time, the upper level trough/low will amplify sharply, causing the coastal to low to blossom into a full-fledged nor`easter off the Mid-Atlantic and Northeast coast. While we won`t see direct impacts from this storm, a tightening pressure gradient and deep troughing will keep plenty of low to mid-level moisture and a northwest to northerly upslope flow over the forecast area Monday into Tuesday. This will lead to a periods of upslope snow showers, likely enhanced by upper level vort energy Monday afternoon and night. However, model soundings are rather unimpressive, showing fairly stable conditions above a shallow boundary layer and the best omega generally below the dendritic growth zone. Thus mainly smaller crystals are expected leading to lower SLRs and a denser snow. Additionally, temperatures will only be marginally cold at lower elevations, causing some or most of the snow which falls during the daylight hours to melt. Above 1,500 feet, daytime temperatures will be a little cooler, around freezing or colder, which will be more supportive of some light daytime accumulations. Some impacts on the Monday afternoon/evening commute are possible through the higher gaps. Temperatures cooling off into the mid and upper 20s Monday night will be supportive of light accumulations area-wide. Any notable upper level forcing exits early Tuesday morning as a subsidence inversion lowers ahead of incoming ridge axis; but, trapped low-level moisture in the northerly flow off of the Great Lakes will likely result in continued cloudiness and scattered upslope flurries over the hills and mountains east of I-75 through much of the day on Tuesday. Daytime temperatures will again be chilly only topping out in the low to mid 30s, although a few upper 30s are possible west of I-75 where more in the way of sunshine is expected. 00z Wednesday-Friday The timing of the clearing Tuesday night will be dependent on how quickly our northerly moisture feed cuts off, but most models do suggest that high pressure will eventually prevail and clear the skies. The combination of light winds, very dry air aloft, and any lingering snow cover will be nearly ideal for rapid radiational cooling once the skies clear. Lows are currently forecast to range from the upper teens to lower 20s; but, if the clearing occurs earlier in the evening, temperatures could drop several degrees lower, especially in those sheltered snow-covered valleys. After a cold morning, high pressure will ensure a mostly sunny day on Wednesday with temperatures rebounding into the 40s. As the next system approaches Wednesday night, significant differences are noted among the models. The operational Canadian appears to be an outlier solution and has been ignored. Both the GFS and ECMWF show a rapidly deepening low lifting from near the Oklahoma Panhandle to near James Bay by the end of the forecast period but disagree on the system speed and track. The GFS features a faster and more northerly tracking system with some light WAA precipitation Wednesday night followed by a cold front and a period of rainfall from late Thursday into Friday. The ECWMF keeps the WAA precipitation north of the forecast area and is about 12 hours slower and quite a bit wetter with the cold front. Regardless of how this system plays out, thermal profiles indicate that the precipitation will probably remain all liquid. Temperatures on Thursday should easily reach in the 50s before cooling off behind the cold front. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 655 PM EST FRI JAN 29 2021 VFR conditions and light winds will continue through the period as a ridge of high pressure slides across the area. Late in the period, moisture will begin to increase ahead of an approaching system, with an increase in high clouds and some mid clouds likely arriving towards 18Z. These clouds start to lower with a band of light mixed pcpn expected to pass through the terminals by 00Z Sunday. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JP LONG TERM...GEERTSON AVIATION...JP/GREIF
Area Forecast Discussion
National Weather Service Marquette MI
1022 PM EST Fri Jan 29 2021 .SHORT TERM...(This evening through Saturday) Issued at 238 PM EST FRI JAN 29 2021 Water vapor imagery and RAP analysis shows a closed low off the coast of New England with troughing from ne Canada into the ne CONUS. Another mid-level trough is moving onto the West Coast. Between these flanking troughs is a broad ridge centered across the Plains states. As models indicate shortwave energy rounding the base of the long wave trough through southern CA this afternoon, it will then split and drive through the Southern Rockies tonight and the Southern Plains on Sat. This will effectively amplify the mid-level ridging into the Western Great Lakes tonight into Saturday which should result in mostly dry conditions, except for some nw flow flurries into the eastern counties this morning and maybe a light dusting of WAA snow/flurries west half Sat morning. WAA/isentropic ascent ahead of the Plains system will result in increasing mid- level clouds late tonight into Saturday for the west and central U.P. while the eastern part of the U.P could see some clearing late this evening into Sat morning before clouding over Sat afternoon. Min temps will be tricky tonight as there will likely be a window over the interior west half this evening where temps could fall pretty quickly into the single digits under clear skies and generally light winds. Lake clouds and flurries persisting into the east this evening under a light nnw flow will keep temps a bit warmer there into the evening. Conditions will then flip overnight as se winds and mid-level clouds increase west and central ahead of approaching trough from system over the Plains and temps likely level off or rise overnight. Out east, clearing will occur with light ese winds developing and the Canadian model indicates drier, cooler air getting pulled in from Ontario. Went on the colder end of temp guidance over the far eastern counties where min temps should drop into the single digits, perhaps into the single digits blo zero for the se half of Luce County. Saturday, model soundings show the column moistening up with increasing WAA isentropic lift across the area so there could be a dusting of light snow/flurries mainly in the morning over the west half. Some WAA mid-clouds will also work into the eastern cwa in the afternoon. Despite the increase in WAA clouds across the area, there will also be minimal warming in a ese flow with max temps generally rising into the mid to upper 20s. .LONG TERM...(Saturday night through Friday) Issued at 258 PM EST FRI JAN 29 2021 Overall, the long term period starts warm and mostly dry, but more active weather is expected late next week. A vertically stacked low over Missouri at 00z Sunday will track east on Sunday then transfer to the east coast on Monday. Weak warm air advection and associated isentropic lift northeast of this low could squeeze out a couple hundreths of QPF as light snow along the MI/WI border by Sunday morning. A dry layer near 850 mb is the primary inhibiting factor for more widespread light snow. A more amplified upper level flow regime impacts our CWA next week with ridging expected over the Great Lakes region Monday night through Thursday. As a result, another period of much above normal temperatures and generally dry weather is expected across the U.P. early to mid next week. NBM guidance indicates high temperatures near 32F Monday-Thursday ahead of a cold front late Thursday/early Friday. A western trough enters the plains on Wednesday resulting in surface low development across the Central Plains. This low is expected to track northeast into the Great Lakes region Thursday into Friday. Warm air advection precipitation could begin as early as Wednesday night, but more substantial synoptic scale precipitation is expected on Thursday into Friday. Ensemble guidance indicates the low will track across the U.P. implying more substantial impacts for western zones, but overall confidence is low. NBM guidance indicates about 1 inch of QPF across the U.P. falling as wet snow, cold rain, or a mix of both. A much colder air mass behind the low should allow synoptic precipitation to transition to lake effect snow for Friday into Saturday. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1022 PM EST FRI JAN 29 2021 VFR conditions will continue into Sat morning at all terminals. WAA mid-clouds will move in later tonight ahead of a system moving through the Plains. MVFR clouds will move in Saturday morning at all sites. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 238 PM EST FRI JAN 29 2021 With a ridge of high pressure moving over the lake today, winds will remain on the lighter side. As the high shifts east tonight, E to SE winds will increase to around 20 knots west and north central late tonight, before increasing to 20 to 25 knots across the lake Saturday afternoon. Could be some gusts approaching 30 knots west half Sat afternoon. Easterly winds will remain around 20 knots through Saturday night and then generally fall blo 20 knots on Sunday as a system passes to the south through the Ohio River Valley on Sunday afternoon. Beyond Sunday, high pressure will remain over the lake through the middle of the week, with light winds prevailing. E-NE winds will likely increase toward gales late next week with the expected approach of system from the central Plains. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...EK AVIATION...07 MARINE...Voss
Area Forecast Discussion
National Weather Service Pocatello ID
135 PM MST Fri Jan 29 2021 .SHORT TERM...Tonight through Sunday night. Early afternoon satellite imagery was showing a split upper through moving onshore with the drier looking NRN branch advancing through Washington/Oregon and the more dynamic SRN branch pushing east through SRN California. The trough axis and associated instability are expected to work from west to east across SRN Idaho late this afternoon and evening promoting an enhanced band of rain and snow showers across the area. The trough clears the Wyoming border early Saturday morning with a drier west flow trailing across the region. We do expect one last punch of snowfall across the mountains this evening with the passing trough and thus have extended to current hazards (Warnings and Advisories) until 10 PM. We should see drying across the west later this evening and overnight as the storm activity transitions into the ERN mountains. Accumulations run up into Advisory levels at higher elevations across the ERN mountains overnight and thus have blanketed the region with a Winter Weather Advisory through Saturday morning. A ridge of higher pressure begins to build across Idaho Saturday afternoon and night as the next Pacific storm system advances into the NW coastal waters. With the ridge overhead Sunday morning we might see areas of freezing fog and low clouds (stratus) within the Snake River Plain. Little change is noted in the overall pattern through Sunday night as several disturbances cycle about the low. That should change sometime Monday/Monday night (more on that below). Seasonable temperatures should prevail through the forecast period. Huston .LONG TERM...Monday through next Friday. Models develop upper troughing off the Pacific coast and deepen it into WA/OR/CA by Tuesday. The moisture ahead of the trough should begin to impact the Central Mountains late Monday night. Moisture is expected to spread to most of the forecast area by Tuesday. Both the GFS and ECMWF cut off an upper low over UT/AZ on Wednesday, though the GFS is still about 12 hours faster than the the ECMWF with the track of the low. Ensemble clusters indeed show variance in the position of the upper trough with the members favoring their deterministic counterparts. One final system impacting the region next week is a reinforcing upper trough moving in from the northwest Thursday night through Friday per the GFS/EC. The Canadian model also shows this feature, but brings it to Idaho about 24 hours later than the GFS/EC. Hinsberger && .AVIATION...A moist southwesterly flow will continue through this evening. KSUN is still getting upslope conditions contributing to the reduced ceiling/visibility. KPIH and KBYI will be strongly downsloped again today until the surface cold front passes through later this evening. The front may produce a quick burst of snowshowers. HRRR forecast reflectivity is indicating strong convection along the front--possibly generating some thunder. NBM guidance is keeping some MVFR ceilings in behind the cold front, though it`s less likely at KDIJ and KSUN. Hinsberger && .PIH WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 10 AM MST Saturday for IDZ064. Winter Storm Warning until 10 PM MST this evening for IDZ066-067-069- 073>075. Winter Weather Advisory until 10 PM MST this evening for IDZ052-068- 072. Winter Weather Advisory from 10 PM this evening to 10 AM MST Saturday for IDZ060>063-065-066. && $$
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
700 PM EST Fri Jan 29 2021 .DISCUSSION... Late afternoon analysis has upper level ridging stretching north over the nation`s mid-section...with an axis along the Mississippi River Valley. Surface high pressure centered in the upper Great Lakes region sprawls down into the Gulf of Mexico. The RAP model slides these features into the eastern states by late Sat. A stable and generally dry air mass prevails across the area. However the boundary flow shifts from light northeast tonight to east then southeasterly during Sat. This will allow temperatures to warm and also provide a subtle increase in moisture...just enough for a few to scattered clouds. Tonight will again be on the chilly side but not as low as last night. Patchy frost will be possible with the most likely locations in the north. && .AVIATION... 30/00Z. VFR. SKC gives way to FEW-SCT CU/CI AFT 14-15Z. Light NE winds become E then SE to S Sat AOB 10KT. && .MARINE... High pressure slides across the eastern US and out over the Atlantic during the weekend with winds slowly 15 knots or less. The high pressure moves away Sun night as a cold front approaches with showers and a few thunderstorms. Winds shift and increase...up to 20 high pressure builds in Mon. && .Preliminary Point Temps/PoPs... TPA 49 71 58 74 / 0 0 0 10 FMY 51 75 59 76 / 0 0 0 0 GIF 46 73 54 77 / 0 0 0 0 SRQ 49 73 58 75 / 0 0 0 10 BKV 40 73 52 77 / 0 0 0 10 SPG 51 70 59 72 / 0 0 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ DISCUSSION/AVIATION/MARINE...09/Rude UPPER AIR...04/Sobien DECISION SUPPORT...04/Sobien