Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/06/23

Area Forecast Discussion
National Weather Service Binghamton NY
728 PM EST Sun Mar 5 2023 .SYNOPSIS... High pressure will build into the area overnight, but clouds will persist. A clipper system will bring some accumulating snow Monday Night into Tuesday, mainly across the Twin Tiers and Poconos of northeast PA. && .NEAR TERM /THROUGH MONDAY/... 7 PM Update... Near term forecast remains nicely on track. Stratus clouds, along with a few sprinkles and flurries continue to stream over the region under the relatively cold northwest flow. CAMs continue to show this flurry/sprinkle activity tapering off by late evening, but the clouds hang on well into Monday morning. There could be some partial sun breaks late morning or early afternoon before more mid/high level clouds arrive from the west. Still a good deal of uncertainty on where a snow band will set up with the incoming clipper system Monday night...although the latest HRRR and RAP do push some snow north into the Twin Tiers and even parts of Central NY, along with all of NE PA. We will continue to closely monitor trends with this system. 3 PM Forecast... A few flurries and/or sprinkles, mainly around Otsego and Delaware Counties, will exit the area early this evening. Surface ridge will be moving in overnight, but with N to NW low level flow persisting, low clouds will stay in place over most areas tonight. Attention shifts to Monday night`s clipper system for which the forecast remains stubbornly uncertain. The basic set up is a weak surface low over northern IL Monday morning will move into western PA Monday evening, then slide ESE towards the Delmarva Peninsula by Tuesday morning. Meanwhile, our surface ridge axis will shift NE into northern NY and New England. This will keep northerly low-level flow in place across NY, while southerly flow attempts to nose in from the south. A WNW-ESE oriented low level frontogenesis band looks to set up, bringing a band of light precipitation to the Twin Tiers and Wyoming Valley. Several models suggest a narrow band of locally heavier precip will develop across the area. The NAM is the furthest north, producing liquid QPF amounts of 0.50 to 0.65 inches from the southern ends of the Finger Lakes into the Southern Tier and Catskills through midday Tuesday. The GFS is more intense, but further south, focused across the Scranton/W-B metro and the Poconos. The ECMWF is much weaker and brings only light QPF of 0.05 to 0.20 inches to the area. Meanwhile, the 12Z HREF members (aside from the FV3) target the Twin Tiers, and thread the needle north of S/WB. Ensemble products are also all over the place. The 12Z GFS ensembles for KBGM brings 24hr snowfall (10:1 ratio) ranging between 0.1 and 10 inches. The "thread the needle" solution seems to be the best compromise, with 2-4" amounts stretching from southern Steuben County (NY) into the Poconos, and just north of Scranton. Warmer temperatures and perhaps a bit of sleet in the southern Wyoming Valley could diminish accumulation significantly in lower elevations. Trying to pin down the mesoscale band, is not really possible at this time, but locally higher amounts will be possible. With the drier air filtering in from the north, expect a sharp cutoff to precipitation on the north side. With the uncertainty, especially with the 12Z ECMWF still coming in so far south, we held off on advisories for the time being. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... 210 PM Forecast... A strong and elongated ridge of high pressure centered over central Canada will extend into the CWA Tuesday night. This will bring NW flow and cooler temperatures to the region. 850mb temps Tuesday night look to be around -13C, which will be cold enough to kick off lake effect snow showers off Lake Ontario. Lake effect showers could reach all the way into NEPA, given NNW flow will allow for the chance of Finger Lakes streamers to develop. Snow totals are expected to be very light, with up to an inch expected across the Finger Lakes and trace amounts in the Twin Tiers. NW flow will continue through Wednesday night, keeping the chance for light lake effect snow showers and flurries continuing through the period. NW flow and cloud cover will keep temperatures cooler than normal for this time of year, with highs in the upper 20s to low 30s for highs Tuesday and Wednesday and lows in the upper teens to low 20s Tuesday night and low to mid 20s on Wednesday night. && .LONG TERM /THURSDAY THROUGH SUNDAY/... 210 PM Forecast... The elongated axis of high pressure will build into the region Thursday, disrupting flow and ending chances for lake effect showers. Temps will still be cool Thursday as the Canadian airmass hangs around with NE flow over the area. WAA returns as the ridge slides eastward Thursday night into Friday. Temps should climbing back to near normal with highs in the upper 30s to mid 40s. The next storm system will impact the region this weekend. Model guidance solutions vary greatly with how the atmosphere will develop. It does look like precipitation will Friday night through Saturday, but how the precip develops and in what mode is still in question. Current forecast used ensemble guidance and capped PoPs at chance due to the uncertainty present. Given the large spread of uncertainty, model guidance should vary greatly over the next several runs but should come into better focus by Wed. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... MVFR stratus clouds look to persist through at least 04-06z at most taf sites; except ELM and AVP which will see intermittent VFR CIGs. The lower MVFR/IFR clouds shift away from SYR and RME late tonight or early Monday morning, as the flow turns northerly and high pressure builds in. BGM/ITH and ELM look to hold onto the MVFR/Fuel alternate CIGs the longest, until around 15-18z Monday. Then VFR cloud bases are expected areawide Monday afternoon before any light rain or snow develop after 00z Tuesday. North-Northwest winds 5 to 15 kts expected through the period. Outlook... Monday night and Tuesday...Restrictions likely as another weather system brings snow. Worst conditions in the Southern Tier of NY and NE PA. Wednesday and Thursday...Restrictions possible with lake effect snow showers; mainly Central NY sites. Friday...Mainly VFR under high pressure. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...MJM/MPH NEAR TERM...MJM/MPH SHORT TERM...JTC LONG TERM...JTC AVIATION...MJM/MPH/TAC
Area Forecast Discussion
National Weather Service Cheyenne WY
517 PM MST Sun Mar 5 2023 .UPDATE... Issued at 513 PM MST Sun Mar 5 2023 Allowed current Winter Weather Advisories to expire. Latest HRRR guidance showing snow ending over the western mountains. Followed its guidance and allowed the advisories to expire. Updates have been sent. && .SHORT TERM...(Late this afternoon through Tuesday night) Issued at 300 PM MST Sun Mar 5 2023 A cold front extended from just east of Chadron and Scottsbluff to Kimball. Winds shifted to the northwest and were gusting to 45 MPH. The temperature at Cheyenne dropped 15 degrees (48 to 33). The HRRR did a good job developing banded snow showers ahead of the front, with a snow squall that impacted parts of I-25 and I-80 from Laramie to just north and west of Cheyenne late this morning. Snow showers will continue, mainly west of I-25 through late afternoon. The Winter Weather Advisory for WY Zones 110, 112 and 114 remains in effect until 5 PM. An active southwest flow aloft with embedded shortwaves beneath a 150kt 250mb jet will provide the large scale lift, with enhancement from surface convergence along a stalled boundary bisecting the CWA from northeast to southwest. Snow showers will be focused from the mountains east and northeast through the high plains. The 18Z WPC guidance QPF trended down slightly from 06Z, with 0.25 to 0.50 inch. Snow accumulations over the 60-hour period will range from 4 to 8 inches for elevations above 8000 feet, and 1 to 3 inches below. Weaker low level pressure/height gradients will preclude strong winds, but it will be blustery at times. Due to the prolonged nature of the snowfall, did not consider issuing a Winter Weather Advisory at this time. Later shifts can reevaluate with new model data. Temperatures will average 10 to 15 degrees below normal with daytime highs in the 20s and 30s. Nighttime lows will range from the single digits and lower teens west, to the mid teens to mid 20s east. .LONG TERM...(Wednesday through Sunday) Issued at 300 PM MST Sun Mar 5 2023 The main focus of the long term forecast remains the potential winter storm on Wednesday through Friday. However, there have been significant changes to model consensus over the last 24 hours that have reduced the odds of a major storm. Current consensus now tilts towards a minor to moderate impact event for portions of the area for Wednesday night through Thursday, though model disparity remains that will be detailed below. On Wednesday, we expect to have a stalled frontal boundary remaining over our area with continued southwest flow aloft. A surface high over the Canadian prairie will lead to increasing MSLP headed to the northeast of us, and thus low-level upslope flow along and east of the Laramie Range. Expect this to keep cold temperatures and low clouds mostly locked in through much of the week ahead. Looking aloft, an earlier weak shortwave will be skirting away from our area, while another approaches from the west. We should be able to have a lull sometime Tuesday night or Wednesday, but kept low end PoPs for most of the area through this break due to timing discrepancies. This second approaching shortwave will likely be the most noteworthy of the week, but models have backed off significantly over the last 24 hours. Yesterday, GEFS mean 500-mb height anomalies had an upper level low associated with the main longwave trough moving directly over the Four corners, which is a concerning pattern. However, the GFS and GEFS have come much more in line with the ECMWF solution with today`s model runs. Now, the most likely scenario involves the main, stronger upper level low hanging back off the coast of the Pacific Northwest, while a shallower, weaker open wave ejects out ahead of it across our area. This scenario is a much faster with less favorable dynamics across our area. The GFS still shows a period of modest isentropic lift overrunning the stalled frontal boundary with low- level upslope flow Wednesday night, leading to a period of widespread light to moderate snow along and east of the Laramie range. Such a scenario would lead to widespread QPF values around 0.5 to 0.75" for much of the area along and east of the Laramie range. However, even after its considerable drop over the last 24 hours, the deterministic GFS remains on the high end of the ensemble spread. Considering KCYS, about 1/10 of the ECE members and 1/3 of the GEFS members show 0.5" or more QPF through early Friday. The ECE mean is now about 0.25" and the GEFS mean is around 0.5" owing to greater consensus around the shallower, more progressive trough solution. There are certainly known under- dispersion issues with these major ensemble systems though, so we can`t rule out a significant storm still occurring just yet, though the odds have decreased considerably. Right now, the most likely scenario involves widespread light to moderate snow overspreading much of the area Wednesday night through Thursday, leading to advisory criteria totals for much of the area, with perhaps some warning level snow possible in favored upslope areas such as the southern Laramie range and Pine Ridge. The low-end scenario is well depicted by the deterministic ECMWF, showing little to no accumulation for most of the area except areas near and north of US20. The high end scenario, shown on a few GEFS members, shows a stronger but still progressive upper level low bringing briefly heavy snow and stronger winds, leading to more widespread warning criteria snowfall and northwest winds on the backside causing some blowing snow headaches. At this time, the official forecast reflects the ensemble consensus described above. Looking towards Friday through next weekend, we start to see some significant spread in the ensemble forecast. The leftover upper level low near the Pacific Northwest coast is the main culprit of this uncertainty. Whereas some solutions have this low starting to track eastward shortly after the first low described above, others keep it hung up in this area for several days longer. Regardless, a period of moist westerly flow aloft looks likely to resume by late Friday into Saturday and bring mountain snowfall back into the picture after a brief lull late Thursday and Friday. There is strong consensus on temperatures remaining below average through Friday, but an increasing proportion of ensemble members (particularly ECE) are breaking the tight grip of the cold temperatures by the weekend and bringing near normal temperatures back to the picture for Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 423 PM MST Sun Mar 5 2023 VFR is expected at all terminals this evening. However, low CIGs and VIS are anticipated at KCDR and KAIA near 12Z Monday morning. This will bring IFR/MVFR to those terminals. Reduced CIGs and VIS can also be expected at KLAR and KRWL on Monday as -SHSN spreads across the area beginning after 12Z and moving slowly to the east. MVFR and IFR is possible during this time for the SE WY terminals. Additional terminals may see MVFR conditions, but confidence is not high at this time for it being included in the TAFs. && .FIRE WEATHER... Issued at 300 PM MST Sun Mar 5 2023 Fire weather concerns will be low this week as a cold and unsettled weather pattern dominates the region. A series of low pressure systems will produce periods of light to moderate snow and blustery conditions. Minimum relative humidities will remain well above critical thresholds. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...GCC SHORT TERM...MAJ LONG TERM...MN AVIATION...BW FIRE WEATHER...MAJ
National Weather Service Hastings NE
548 PM CST Sun Mar 5 2023 ...AVIATION UPDATE... .DISCUSSION...(This evening through Sunday) Issued at 233 PM CST Sun Mar 5 2023 Key Messages: * A cold front will bring mostly cloudy skies and cooler temperatures to start the work week. * Unsettled weather could begin as early as Tuesday night, although the brunt of the next system is not expected until Thursday. * Models have trended weaker and further north with the mid-week system, focusing snow to our north and bringing a mix of rain and snow to the tri-cities area. Still plenty of time for changes as this system is still nearly 4 days away - although model agreement and trends do not look promising for much in the way of snowfall at this time. * Below normal temperatures are expected for the end of the week and into next weekend, although with normals climbing rapidly this time of year, bitterly cold weather is not anticipated. A very nice afternoon is being observed across the local area today with afternoon temperatures 15 to 20 degrees above seasonal norms and generally light southerly winds. The main exception is across north central Kansas where these above normal temperatures are being accompanied by occasionally gusty southerly winds...which is resulting in elevated to near critical fire weather concerns in a few spots. That said...expect winds to continue to diminish through the remainder of the afternoon...helping to alleviate the fire concerns. For tonight...expect a cold front to our northwest to push south across the local area by daybreak...with breezy northerly winds and cooler temperatures in its wake. This cold front is helping to fire up a couple of thunderstorms across the Nebraska panhandle this afternoon...but is not expected to bring any precipitation locally. While temperatures will be noticably cooler behind this cold front on Monday, they will remain seasonable...with most locations reaching the 40s and lower 50s by afternoon. In addition to the winds and cooler temperatures...expect a fair amount of cloud cover through the day, with low level stratus expected to invade the local area before daybreak Monday...eventually thinning out later in the day. The HRRR seems to be the outlier for tomorrow...with dense fog depicted covering much of the local area by daybreak...and discounted this idea mainly due to steady and breezy north winds as well as significant cloud cover advecting in overnight...although a very narrow band of denser fog cannot be completely ruled out on the leading edge of the incoming stratus. For the remainder of the period...expect west southwesterly flow aloft to continue across the region...with a quick passing upper disturbance in this flow bringing a small chance for precip Tuesday night into Wednesday...with little to no accumulation expected. The better chance for precipitation will come with a deeper upper level trough Thursday/Thursday night. Originally...models were further south with this system...and intensifying it as it crossed the area...but have since trended further north with the 500mb circulation not being intensified until it passes well east of the area. Given the trends...this does not look overly promising for a significant precipitation event across the local area...with the best chance of any rain or snow now mainly across our Nebraska counties...with the higher snowfall accumulations focused across the Dakotas. Will continue to monitor as further changes are possible...but the main impact at this time appears to be below normal temperatures returning for the end of the week and into next weekend...although again...bitterly cold air is not expected. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday) Issued at 531 PM CST Sun Mar 5 2023 Skies have cleared out today and mostly clear skies will persist through the evening hours. Late tonight, there is a chance for low stratus and fog to return from the north...introduced some MVFR to IFR conditions shortly after midnight...perhaps increasing in coverage around daybreak. The real question is whether this is limited to low stratus or if some denser fog develops...there is model guidance supporting both. If this remains low stratus, visibility will remain around 4SM to 5SM in areas of patchy fog...if more widespread fog develops, visibility may drop as low as 1SM or less for a brief period. Elected to go with 3SM to 5SM visibility as more forecast soundings favor that solution and breezy winds should hinder development of denser fog. Either way, visibility will improve after sunrise and ceilings will gradually lift during the morning...VFR conditions are expected from late morning through the end of the TAF period. Winds will be light and variable through around midnight, at which time winds will begin to increase from the north. Winds will continue to increase Monday morning to around 15 kts && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ DISCUSSION...Rossi AVIATION...Hickford
Area Forecast Discussion
National Weather Service Goodland KS
516 PM MST Sun Mar 5 2023 .UPDATE... Issued at 515 PM MST Sun Mar 5 2023 Allowed Red Flag warning to expire due to winds becoming light. UPDATE Issued at 236 PM MST Sun Mar 5 2023 Red Flag Warning for Sherman and Thomas County has been cancelled as winds and relative humidity values have remained well below critical levels. Short term guidance indicates that this trend of below critical criteria winds and humidity will continue through the remainder of the diurnal mixing period, therefore minimizing any threat for the rapid growth and spread of fires if one were to develop. The Red Flag Warning for Cheyenne (CO), Greeley, Wichita, Gove and Logan counties continues through 00Z. && .SHORT TERM...(This evening through Wednesday Morning) Issued at 120 PM MST Sun Mar 5 2023 A surface low is moving across the area with an associated lee trough ejecting off of the Rockies. Warm front has lifted north across the majority of the area along with locations south of I-70 behind a dryline located roughly from Smith Center to Great Bend. Very dry air represented by large dew point depressions is being observed behind the dryline as Scott City is 69/13 and La Junta is 65/1. Breezy to gusty winds are expected to increase through the remainder of the afternoon as mixing increases and the low level wind field strengthens. Based on 1 hour GFS/HRRR guidance it appears that the most likely areas to see multiple hours of critical fire weather will be located south of I-70 with locations along the Interstate seeing perhaps an hour or two during the late afternoon hours. Blowing dust threat continues to diminish and will be removing from the forecast. Overall the Red Flag Warning will remain through the rest of the afternoon. This evening, a cold front moves through the area as winds will switch to the NW. Winds will remain sustained around 10-15 mph as low temperatures into Monday morning will fall into the lower 20s over Yuma County to around freezing over the eastern areas. Monday looks to be a relatively quiet and cooler day with high temperatures in the low 40s to low 50s across the area. Into the evening, winds will become easterly allowing for an upslope component to materialize, a weak shortwave comes off of the mountains leading to the potential for light snow and perhaps light freezing drizzle along and west of the KS/CO border. I have added in the light freezing drizzle for this package as forecast soundings from the GFS/HRRR/NAM all show dry mid-levels with a saturated low level. A warm nose is seen around 750mb, especially south of I-70 across Cheyenne County Colorado and Kit Carson county; north across Yuma guidance differs on if the entire column will be below freezing or exhibit the warm nose so went with a broad -ZL/-SN. It will also be worth monitoring how warm the ground is for any slick spots to develop as temperatures have been warmer and soil temperatures are a few degrees above freezing. Nevertheless be prepared for slick spots if driving across east Colorado Monday night into Tuesday morning especially across bridges and overpasses. Tuesday, will be by far the coolest day of the short term period as all guidance has 850mb temperatures around 0C or less along with mostly cloudy to overcast skies through the day. I did lower high temperatures a few degrees from the NBM using a blend of CONSRAW/MET guidance. As a result many locations will look to struggle to get above the freezing mark Another chance of light snow is possible across NW areas Tuesday night into Wednesday .LONG TERM...(Wednesday through Sunday) Issued at 105 PM MST Sun Mar 5 2023 Wednesday...the forecast area is under southwest flow aloft ahead of an open and approaching upper level trough. During the day, moisture in the 850-700mb layer slowly increases (mainly along and north of I- 70) with a dry slot above 700mb across the entire area. Presently there is a slight chance for some light rain and/or snow along/north of I-70. High temperatures are forecast to range from the middle 30s to middle 40s. Overnight, the 850-700mb layer continues to saturate under northeast to easterly surface winds at speeds of 10 to 15 mph. The GFS/ECMWF models bring some mid level moisture across the northern half of the forecast area as the upper trough approaches. 850mb temperatures hover around 0C with low temperatures in the middle 20s to lower 30s. Will maintain chance to categorical pops for rain/rain and snow/snow depending on location. Snowfall amounts this cycle only a few tenths of an inch. Thursday...GFS/ECMWF/GEM/GEFS models swing the upper trough axis across the area during the day then into Iowa during the night. There is quite a bit of dry air moving through the area while the lower levels remain saturated enough to support some light precipitation. With 850mb temperatures warming from south to north during the day the current forecast highs range from the middle 30s to around 40 along the KS/NE border to the upper 40s across Tribune and Leoti. The warmer temperatures and a lack of mid level moisture support have lowered overall snowfall amounts quite a bit with amounts ranging from zero to one half inch possible, highest across the north where cooler/colder temperatures reside longer. Based on the GFS/ECMWF/GEM 850-500mb relative humidity forecasts and their qpf, its doubtful at this time to get any precipitation during the night but for now will stay with the NBM`s slight chance to chance pops for now. Low temperatures are forecast to be in the lower teens to middle 20s. Friday...the GFS/ECMWF/GEFS models show near zonal flow across the area. Its currently forecast to be dry under increasing mid and high level cloudiness. High temperatures are forecast to be in the middle 30s to lower 40s with overnight lows in the upper teens to lower 20s. Saturday...GFS/ECMWF/GEFS 500mb flow shows a general westerly component. 850-500mb relative humidity is quite high from the GFS when compared to the ECMWF and shows a wave moving through the upper flow during the night, supporting the NBM output of slight chance pops for light rain changing to light snow. There is a large discrepancy in 850mb temperatures during the day with GLD for example showing -3C from the GEM, +4C from the GFS and +15C from the ECMWF. No confidence to stray from NBM output highs in the lower to upper 40s across the area. Low temperatures are forecast to be in the lower to middle 20s. Sunday...the current forecast has a slight chance for some light rain for a few locations along/north of I-70 in the afternoon with high temperatures in the middle 40s to around 50. This could be supported by the GFS which has a weak wave moving through nearly zonal flow aloft and some moisture in the 700-500mb layer moving in from the west. Confidence however is low as the 500mb flow from the ECMWF is similar to the GEFS and is drier throughout the atmosphere compared to the GFS. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 246 PM MST Sun Mar 5 2023 VFR conditions are currently forecasted to persist through this TAF period. Winds will become northwesterly as a cold front moves through the area this evening. Some Hi-Res guidance such as the GLAMP, HRRR have started picking up on a signal for some fog potential Monday morning along and east of Highway 25, which may impact KMCK. I am currently a little skeptical of this as winds look to remain around 10 knots, which typically doesn`t support fog formation. This will continue to be montiored through the evening. Winds will become more ENE throughout the day Monday around 10-12 knots. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...Trigg LONG TERM...99 AVIATION...Trigg
Area Forecast Discussion
National Weather Service Grand Rapids MI
1032 PM EST Sun Mar 5 2023 LATEST UPDATE... Update .UPDATE... Issued at 1032 PM EST Sun Mar 5 2023 A mid level shortwave working east from the plains states towards the Great Lakes is driving strong isentropic lift upstream this evening, best seen on the 295K surface. Upglide is strong on the order of 40-50 knots directly up the surfaces which has led to a significant expansion in precipitation areal extent and intensity over Iowa, Wisconsin and Northern Illinois. The zone of upglide/lift works east into Lower Michigan in the next few hours and continues overnight. The precipitation is occurring from elevated bases between 850mb and 700mb. This is seen in cloud bases of 6,000 to 8,000 feet upstream. The HRRR brings some weak instability into the area tonight on the order of 200-400 j/kg at max. Plenty of lightning occurring upstream as well as a few reports of small hail. We will likely see some lightning sneak into the area late, but not expecting any convection that results in anything too serious. Precipitation type should mainly be rain across the southwest portion of the forecast area (south and west of GRR) with a mix of rain/snow or snow elsewhere. Given the convective nature of the precipitation we will see some snowfall rates overnight across Central Lower Michigan that will at least reach moderate levels. 1-3 inches of snow is certainly possible by daybreak up there with some impacts to morning travel. Best chance for accumulations that will reach impactful levels are in the zone where we have a Winter Weather Advisory out and will continue that headline as is. && .DISCUSSION...(This evening through next Sunday) Issued at 209 PM EST Sun Mar 5 2023 - Accumulating snow during the Monday morning commute for Big Rapids, Mt Pleasant and Clare We will issue a winter weather advisory for that region. Difficult forecast for snow amounts and/or potential for a period of freezing rain for the Monday morning commute. The area of developing precipitation in northern IA and eastern SD is forecast to track into Lower MI later tonight and through the CWA Monday morning. Driving this precipitation is a 40 to 50 LLJ occuring underneath a mid level wave that features some FGEN. Theta E was decreasing with height in this area of precipitation in the 700/500 mb layer. That decrease in Theta E with height is forecast to increase over the next couple of hours as the LLJ strengthens. This setup does not change much as the system moves into our CWA late tonight. Like many of the models are showing...the precipitation should continue to expand as it moves into southwest Lower MI and it could be convective. It`s unclear what the surface temperatures will be like when the precipitation moves in...mainly due to the convective potential of this system. Higher precipitation rates will drive down the surface temperatures...while lighter rates may allow them to stay a few degrees above freezing limiting the impacts. Confidence on the surface temperatures nearing freezing temperatures is highest near and north of a White Cloud to Mount Pleasant line which is where we will feature a winter weather advisory. Ensemble mean 24 hr snowfall for Mt Pleasant from the GFS...Canadian and ECMWF support a 2 to 5 inch snowfall for that region. It`s worth noting at several high res models including the NAM an RAP are further south with the accumulating snow and would suggest drawing that advisory further south. Our confidence on this happening is not high enough to feature a headline for places like Grand Rapids or Lansing but it is something that will need to be monitored/considered on later shifts depending on the trends. As for the freezing rain potential...given the idea of heavier bursts of precipitation due to the convective nature of this system...we will limit the freezing rain risk. If it does should be of a short duration. - Impacts possible from the storm system for the end of next week For several runs in a row the models have been showing a low pressure system tracking through the southern Great Lakes region. The forecast area is shown to be in the baroclinic zone. Stronger mid level height fall are seen as well. Also, a negative tilt to the wave in the upper levels is noted so upper level diffluence should be supportive of widespread precipitation. The northern zones stand the best chance to stay on the wintry side of the storm where southern zones may swap over to rain. As usual this far out...timing...track and strength differences exist. Ensemble trends in GFS with the 24 hour snowfall have been increasing with this system. We will feature above normal POPs for this end of the week system. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 729 PM EST Sun Mar 5 2023 Low pressure will move from Kansas this evening to Ohio by Monday evening. Precipitation will spread into the area tonight and continue on Monday as a warm front sets up to the south of the state. The precipitation will mainly be in the form of rain at the TAF sites, but there will be some snow that mixes in at the I96 TAF sites tonight. The most widespread and heaviest precipitation will occur tonight and Monday morning between 06z and 15z. In terms of aviation conditions ceilings will slowly lower overnight with IFR conditions settling in. IFR will become dominant during the afternoon hours of Monday. Winds will be from the east at 10-20 knots much of the next 24 hours. The strongest winds will be overnight. && .MARINE... Issued at 209 PM EST Sun Mar 5 2023 The winds will increase considerably tonight as the wave of low pressure moves in. This system will feature a 40 to 50 knot low level jet. The surface flow will feature an offshore component with this system. Commonly this supports slightly less wind than over the open waters. While a few gusts to gale force are possible in the nearshore waters...ensemble mean wind gusts from the ECMWF and GFS keep the values under gale force. For that reason we will hold onto the small craft advisory. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory from 3 AM to 6 PM EST Monday for MIZ038>040-044>046. LM...Small Craft Advisory until 10 AM EST Monday for LMZ844>849. && $$ UPDATE...Duke DISCUSSION...MJS AVIATION...Duke MARINE...MJS
Area Forecast Discussion
National Weather Service New Orleans LA
546 PM CST Sun Mar 5 2023 ...New AVIATION... .SHORT TERM... (This evening through Tuesday) Issued at 317 PM CST Sun Mar 5 2023 Warming trend is expected for the area as the surface high pressure centered north of the area treks eastward and winds turn to south to southeasterly. This warmth will be unseasonably warm (again) but not expecting any record breaking values. Meanwhile, ample moisture from the onshore flow will help bring higher dew points. For tonight and into tomorrow morning, there is some signal for fog, possibly dense, especially for coastal MS and nearby St Tammany/Washington parishes. SREF probabilities, CAM guidance as well as the timing for 100% RH is conducive for fog but the problem is just how dense will it be. Right now, feeling fair confidence on some light patchy fog, but much lower on dense (1/4 sm) fog. Due to this low confidence, held off on a dense fog advisory for now but it will need to be revisited again later tonight. There is a fairly small chance of rain (5-10%) Monday afternoon into the evening due to the higher moisture values and some weak warm advection. Confidence is not super high on this either, but synoptic hour runs of the HRRR has shown some isolated showers, so opted to add a small 10-15% PoPs during this time frame. && .LONG TERM... (Wednesday through Saturday)... Issued at 317 PM CST Sun Mar 5 2023 The central Gulf coast will remain under the influence of a broad and persistent 500mb ridge axis stretching across the entire Gulf of Mexico on Wednesday and Thursday. This ridging will extend down to the surface, and this will keep rain chances suppressed and temperatures well above average both days due to strong deep layer subsidence. Given the strength of the subsidence in place and increasing solar insolation as we move deeper in climatological Spring, temperatures will easily warm into the mid to upper 80s both Wednesday and Thursday over interior areas of the CWA. Closer to the coast, the cooler shelf waters will keep highs in the upper 70s and lower 80s. Overall, the deterministic NBM remains on the lower end of the ensemble spread, and have maintained using NBM 50th percentile values for the temperature forecast on Wednesday and Thursday. At the same time, a persistent onshore flow in the low levels, will increase low level humidity, and a very muggy late Spring and early Summer like feel to the air can be expected. The potential for some advection fog to impact the area will continue to exist on Wednesday morning, but the risk appears to be lower for Thursday morning due to an increase in boundary layer winds. However, overcast skies from a stratus deck will be in place during the early morning hours on Thursday in response to the warmer air moving over the cooler shelf waters. Any stratus will quickly clear by mid-morning as temperatures warm and boundary layer mixing increases. Heading into Friday, all of the deterministic guidance has come into better agreement today. A progressive positively tilted trough axis will eject out of the Four Corners Thursday night and pass through the Plains and Midwest Friday into Friday night. As the trough passes by, a cold front will slide into the area from the northwest on Friday. Increased forcing along the front should produce clouds and showers with the highest rain chances Friday afternoon immediately ahead of the frontal boundary. Based on the lack of strong deep layer forcing and limited instability as noted in model soundings, have opted to stick with a chance POP forecast of 40 to 50 percent for Friday afternoon. There may be an isolated weak thunderstorm that forms along the front, but weak mid-level lapse rates should prohibit any deep and long-sustained convection from forming. Temperatures will remain above average ahead of the front with highs in the upper 70s and lower 80s expected. After the front passes through the area Friday night, winds will shift to the west and northwest, and a drier and cooler airmass will begin to advect into the region. Although a 925mb thermal trough will passing through, temperatures of around 50 degrees at 925mb are supportive of highs near 70 for Saturday afternoon. Overall, a very pleasant day is anticipated due to the lower humidity, near normal temps, and mostly sunny skies. && .AVIATION... (00Z TAFS) Issued at 538 PM CST Sun Mar 5 2023 Model sounding and satellite trend analysis has strengthened confidence that a widespread low stratus and fog IFR event will occur at all of the terminals. This will be a mixed event with radiation fog being the primary concern at MCB and BTR, and advection fog closer to the coast at GPT, ASD, HDC, NEW, MSY, and HUM. IFR and lower Fog and stratus development should initially begin at the coastal terminals of GPT and HUM around 08z as a region of deeper moisture residing just offshore this evening begins to move inland on the back of a developing southerly flow. The advection fog will then spread north and impact MSY, NEW, HDC, and ASD by 10z. Further inland, clear skies and marginally favorable boundary layer winds of around 15 knots will interact with radiational cooling and a developing inversion to induce radiational fog and low stratus development between 09z and 11z. The fog and stratus impacts will be most pronounced from 11z to 15z when the boundary layer is expected to be fully decoupled. After 15z, all of the terminals will see conditions gradually improve as temperatures warm into the 70s and 80s. By 18z, VFR conditions are expected at nearly all of the terminals due to the warming increasing boundary layer mixing. Only GPT could remain in MVFR status with some broken stratus at 1500 feet due to continued warm air advection over the cooler shelf waters. && .AVIATION... (18Z TAFS) Issued at 1144 AM CST Sun Mar 5 2023 VFR conditions will prevail for about half the forecast period before the potential of MVFR or IFR conditions overnight tonight into tomorrow morning due to fog/lower stratus deck settling in. Generally light winds out of the east will turn to out of the south tonight, beginning to pump moisture back into the area. Biggest chances right now are particularly for terminals closer to the coast and the MS sound (KGPT, KASD, KHDC). Other terminals could have some light and patchy fog. Best timing for fog potential would be approx 09z to 16z. -BL && .MARINE... Issued at 317 PM CST Sun Mar 5 2023 Quiet conditions are expected for all the marine areas for the week. Winds currently are in transition to onshore flow as high pressure moves eastward. This light onshore flow pattern will remain through basically the whole week. -BL && .PRELIMINARY POINT TEMPS/POPS... MCB 52 80 63 81 / 0 10 0 10 BTR 58 84 68 85 / 0 10 0 10 ASD 59 83 66 84 / 0 10 0 10 MSY 63 82 68 82 / 0 10 0 0 GPT 59 78 67 79 / 0 10 0 0 PQL 56 81 65 83 / 0 10 0 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...BL LONG TERM....PG AVIATION...PG MARINE...BL
Area Forecast Discussion
National Weather Service Marquette MI
713 PM EST Sun Mar 5 2023 .SHORT TERM...(This evening through Tonight) Issued at 227 PM EST SUN MAR 5 2023 Water vapor imagery and RAP analysis reveal a pair of upstream shortwaves which will be impacting U.P weather later tonight into Monday. One shortwave is over the eastern Dakotas and another is over the northern Rockies. Ridging has yielded mostly sunny skies today over Upper Mi with temperature readings already reaching into the upper 30s to mid 40s across the area. Tonight, the first shortwave from the eastern Dakotas moves in later tonight spreading snow into Upper MI courtesy of isentropic ascent associated with the wave. The ascent looks like it will be strongest into s central Upper MI where stronger winds are noted crossing perpendicular to tightly spaced isobars on the mid-level theta sfcs, and that is where most of the model guidance places the higher qpf, similar to what GFS/CMC/ECMWF ensembles have been showing for days. GFS/CMC/ECMWF also have been showing gradual downward trends in qpf with a less aggressive n and ne advance of pcpn tonight. With some of the CAMs, particularly the RAP and HRRR, starting to trend in that direction as well, will lean the pcpn fcst tonight toward the global models which have been leading the way on this event. The 12Z NAM remains the farther north outlier solution. Expect -sn to spread out of WI into the Ironwood area in the late evening, then advance n and e thru the night. The snow may struggle to reach the Keweenaw and the far eastern fcst area by 12z Mon as antecedent dry air and weaker ascent work to limit the advance of snow. Away from those areas, expect snow accumulations of 1-3 inches by 12z Mon, greatest across s central Upper MI and in particular across Menominee County. Will continue the Winter Weather Advisory for the south central counties late tonight into Monday and will keep Marquette County in the advisory mainly for additional expected snowfall and potential lake enhancement Monday into Monday evening off of Lake Superior in a ene wind direction. .LONG TERM...(Monday through Sunday) Issued at 324 PM EST SUN MAR 5 2023 Overall, not much has changed since yesterday with the primary focus continuing to be the wet snow event that ends Monday night. Tuesday- Thursday still looks like a nice stretch of mostly sunny weather with warm, sunny days and cool, clear nights. Potential still exists for a longer-duration event late this week, but confidence remains low. A general trend from above- to below-normal temperatures is expected throughout the extended period, but expect the whole week to average above normal for most. Overall near normal precip is expected, but that will depend on what happens late this week. Starting at 12z Monday, a ~1008 mb surface low will be positioned near Kansas City, MO with a broad precipitation shield displaced well to the north across portions of MN/WI/MI. 12z Global models continue to be farther south than CAMs with the axis of heaviest precip, but the 15z RAP trended toward global models. The 12z NAM/HRRR were considered outliers for this forecast package, which also suggests HREF guidance is questionable. For the 12-hour period between 12z Monday and 00z Tuesday the general consensus is for less than 0.20" of QPF for all but the central UP where easterly upslope flow may locally squeeze out >0.3" of QPF. Most models show two local maxima, 1) over Marquette County where enhancement off Lake Superior is possible and 2) over Menominee and Delta Counties where enhancement of Lake MI seems more likely. Even though I trimmed QPF substantially, I`m still not confident that the totals forecast for Marquette County will materialize. Since precip rates aren`t expected to be heavy, marginal surface temperatures and relatively strong March sun may limit travel impacts especially during the afternoon at lower elevations. A few hundredths of additional QPF are expected Monday night, but the greater hazard may be associated with patchy ice from refreezing of wet roads/sidewalks. Tuesday through Thursday looks like a stretch of superb weather with warm, mostly sunny days and cool, mostly clear nights. Ensemble median 850mb temps are generally in the -8C to -10C range, which may be cool enough for lake effect clouds and flurries at times. However, the very dry air mass suggests mostly sunny/clear skies should prevail at most places. Slightly increased Tmax for Tue-Thu into the and decreased Tmin for Tue and Wed nights. Diurnal temp ranges around 30F seem possible across the interior with lows around 10F and highs around 40F. By Thursday evening a low pressure should be developing across the South-Central Plains that lifts northeast toward the Lower Great Lakes on Friday. This is somewhat faster than yesterday`s model solutions suggesting snow may begin Thursday night and transition to lake effect by Friday night or Saturday morning. Overall, model-to- model and run-to-run differences continue to be large and this should continue until the early week system moves away. GFS/CMC and associated ensemble solutions favor a longer duration event whereas ECMWF/EPS solutions do not. There does appear to be good agreement that the post-system air mass will be cold enough for pure lake effect as 850 temps cool to around -15C. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 713 PM EST SUN MAR 5 2023 VFR conditions will prevail into tonight before deteriorating tonight as the next disturbance spreads snow over Upper Michigan. Initially, terminals will lower to MVFR and eventually IFR or worse around daybreak. Meanwhile, easterly winds will become strong tomorrow afternoon at IWD and CMX with sustained speeds in excess of 12 kts and gusts to 22 kts. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 324 PM EST SUN MAR 5 2023 Ridging over the lake keeps wind gusts below 20 knots until around midnight when easterly wind gusts increase to 20 to 25 knots, then increasing to 35 knot gales across the far western lake Monday morning. Elsewhere, gusts increase to between 20 and 30 knots on Monday before diminishing below 20 knots late Monday night. Despite generally high pressure over the lake, the gradient between lower pressure to the south and a 1050mb high over central Canada will keep wind gusts around 20 knots through the midweek. Wind gusts increase Thursday evening and into the weekend as a low pressure tracks into the Great Lakes region, but uncertainty in the low track makes forecast details difficult. However, should the low pressure track near Lake Superior, gales are possible for the late week and early weekend. Waves of 8 to 11 feet are expected on Monday and are possible for the late week and weekend period if the low pressure tracks close enough. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory from 4 AM Monday to 1 AM EST Tuesday for MIZ005. Winter Weather Advisory from 1 AM EST /midnight CST/ to 7 PM EST /6 PM CST/ Monday for MIZ010>013. Lake Superior... Gale Warning from 7 AM EST /6 AM CST/ to 7 PM EST /6 PM CST/ Monday for LSZ162. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...EK AVIATION...TDUD MARINE...EK
Area Forecast Discussion
National Weather Service Pueblo CO
711 PM MST Sun Mar 5 2023 .UPDATE... Issued at 654 PM MST Sun Mar 5 2023 Winds are decreasing and humidity values are starting to increase across much of the area, therefore, have allowed much of the High Wind Warnings and Red Flag Warnings to expire. With that said though, conditions remain favorable for strong winds overnight across the Southern Sangre de Cristo Mountains, Walsenburg Vicinity/Upper Huerfano River Basin Below 7500 Feet, and western Las Animas County, where a High Wind Warning remains in effect until 8 AM Monday morning. Also, while winds have decreased and humidities increased, a Red Flag Warning remains in effect for parts of Huerfano County from 11 AM to 6 PM Monday, where winds will again become gusty and humidity values are expected to drop to around 10 percent. && .SHORT TERM...(This evening through Monday) Issued at 225 PM MST Sun Mar 5 2023 ...Very strong damaging winds and Red Flag conditions will remain in place over portions of Southeast Colorado through the early evening... Key messages: 1) Very strong and damaging winds, with areas of blowing dust, will still be possible over portions of the San Luis Valley and plains through the evening. Stronger winds will remain longer into the early morning hours over the southern I-25 corridor. 2) Severe crosswinds could make travel dangerous over portions of the southern I-25 corridor for high profile vehicles through the early evening hours. 3) Critical fire weather conditions over the plains and Palmer Divide will continue into the early evening hours. Critical fire weather conditions are expected again tomorrow afternoon for Huerfano County, and spotty conditions over areas of western Las Animas County and the San Luis Valley. 4) Lingering snow showers over the northern Sawatch Range will be winding down later this evening. There could still be some blowing snow until then. Detailed discussion: Currently and tonight... A longwave trough upstream is forcing a weak perturbation trough over the area with very strong winds aloft between the 700 to 500 mb level of over 100 mph. The tightening of the surface pressure gradient, combined with brute forcing has allowed for very strong winds and areas of blowing dust to be present over many of the lower elevations in southeast Colorado. Strongest winds are currently in the Walsenburg area, with gap flow winds through La Veta Pass further enhancing some of the stronger gusts. This aligns with what a lot of the higher resolution guidance is showing. Given this, severe crosswinds could make travel dangerous over portions of the southern I-25 corridor for high profile vehicles through the early evening hours. Some of the higher resolution models, such as the NAMNest and HRRR have the strongest winds also begin just downwind of the southern Sangres and this is sticking around until the early morning hours tomorrow with reverse shear showing up in the cross sections over these areas, alluding to the likely occurrence of this. Extreme fire weather conditions currently across the plains and Palmer Divide will end by the early evening hours as winds begin to subside, and relative humidities recover after sunset. A cold frontal boundary with relatively cooler air behind it will move through during the late evening hours through early morning hours tomorrow. HRRR has this moving through a little quicker than some of the other high res models, between 8 and 9 PM over Kiowa County. This will allow for winds to become northeasterly across the plains Forecasting low temperatures has been a challenge along locations of the southern I-25 corridor, given the uncertainty of how far west the boundary will make it with the strong westerly winds shooting through the gap. Therefore temperatures have not been modified too much, but there is the possibility that some locations near the Walsenburg area could see temperatures as much as 10 degrees warmer if the winds remain persistent out of the west through sunrise. Otherwise, temperatures will cool off quite a bit over a majority of the plains, getting down into the low to mid 20s for most locations. In high country, the lows will drop into the teens and low 20s for the higher mountain valleys and San Luis Valley, which is relatively warmer due to mixing with the winds, and some single digits for the higher elevations. Tomorrow... Longwave troughing will remain in place upstream with slight ridging over the region. This will allow for winds to diminish a bit and dry conditions to be predominant across all of southeast Colorado. Winds are still going to be gusty, but not nearly as strong tomorrow. There will be some areas along the southern I-25 corridor, mainly Huerfano County, which will still experience stronger gusts with lower relative humidity values during the afternoon. Therefore, critical fire weather conditions will be likely over areas of Huerfano County, and there could be some spotty areas in western Las Animas County, as well as in the San Luis Valley. Highs tomorrow will be cooler with easterly winds in place across most of the plains, and back around the seasonal average for this time of year. The San Luis Valley will still remain on the more mild side, due to the downsloping westerly winds still in place. -Stewey .LONG TERM...(Monday night through Sunday) Issued at 225 PM MST Sun Mar 5 2023 Key Messages: 1. Cold front will waver north to south across southeast CO resulting in a challenging temperature forecast through mid week. 2. Potential exist for freezing drizzle across El Paso county and portions of the southeast plains Monday Night and Tuesday and possibly again Tuesday night into Wednesday. Persistent southwest flow over the area through mid week will bring mild temperatures and breezy to windy conditions across the mountains and valleys. Meanwhile, a cold front will be wavering northwest to southeast each day across the plains resulting in a challenging high temperature forecast depending on where the cold front lays up. This cold front will surge westward Monday night with shallow saturation occuring across the southeast plains towards morning, bringing the potential for drizzle and freezing drizzle along and east of a line from Air Force Academy to Canon City to Springfield. Area of greatest concern for will be across El Paso and eastern Fremont counties where east to southeast upslope flow will maximize orographic lift on the south side of the Palmer Divide and against the higher terrain in eastern Fremont county. Less confidence exists farther south across the east slopes of the Wet mountains where a non-zero risk of some light icing could occur. For now think some minor ice accumulations will more likely stay confined to El Paso county where elevated surfaces may become cold enough for some light ice accumulation early Tuesday morning. Have introduced some fog into the forecast as well. Will need to monitor this area for the potential for slick spots, particularly bridges and overpasses. For now, models are suggesting a Trace to 0.01 on the high side of accumulations, which would suggest only minor impacts to travel. Otherwise, high temperatures show quite a bit of variability within the NBM and guidance across the plains Tuesday. Leaned towards the colder side of guidance, especially across El Paso county where low clouds are likely to linger through most if not all of the day. Greatest uncertainty exists at KSPD where guidance and NBM probs gives a range of highs from from 35 to 65. Stuck with highs generally in the 40s for now. Will have to watch the southern I-25 corridor counties for a return of critical fire weather conditions Tuesday afternoon, but suspect that the cold air will be stubborn to erode and we won`t quite make the 3 hours duration for fire weather highlights. The cold front will make another push westward Tuesday night with another round of drizzle and freezing drizzle possible Tuesday night into Wednesday morning. NBM pops are not picking up on this potential, and with some uncertainty as to how deep and cold the saturated layer will be have left FZDZ out of the grids for now. This will need to be reassessed as higher res models begin to resolve these details. But signals are there for a repeat performance of freezing drizzle which could extend down into the southern I-25 corridor as well. High temperatures on Wednesday are in jeopardy of being colder than the optimistic NBM suggests and have shaded them down across the plains in some areas. With the approach of the next upper trough into the Great Basin Wednesday afternoon some light snow will develop along the Continental Divide with some overrunning precipitation, rain and snow showers, across the Pikes Peak region during the afternoon. This upper trough will glance by to the north Wednesday night and Thursday bringing some light precipitation to northern areas. With a more northerly track to this system, precipitation chances for the plains will be not be all that great, but there could some brief showers along the cold Thursday afternoon and evening. Generally zonal flow will bring another chance for mountain showers into western areas Friday night into next weekend though there is quite a bit of variability in the models and ensembles. The operational GFS much more amplified with another trough coming in for late weekend. EC and EPS show a zonal to even a weak ridging pattern with GEFS also much less amplified the operational GFS and leaning towards a drier solution. Will keep majority of the pops confined to the Continental Divide for now. -KT && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 225 PM MST Sun Mar 5 2023 VFR conditions are expected to prevail for all TAF sites (KALS, KCOS, and KPUB) throughout the forecast period. Winds will be synoptically influenced at all terminals. They are currently very strong and gusty out of the SW, especially at KALS and KPUB where gusts could occasionally reach 45 kts, and BLDU will still be possible until 02Z at KALS and 01Z at KPUB. If this does occur, it could bring down VIS temporarily to IFR/LIFR criteria. Winds will begin to diminish and shift more to the SSW at KALS and then back to the SW again, becoming gusty after 15Z and through the remainder of the forecast period. At KCOS and KPUB, they will also weaken and come around to the NNE and NE, and eventually SE and SSE respectively, and remain that way through the end of the forecast period. && .PUB WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 8 AM MST Monday for COZ074-075-087-088. Red Flag Warning from 11 AM to 6 PM MST Monday for COZ229. && $$ UPDATE...SIMCOE SHORT TERM...STEWARD LONG TERM...KT AVIATION...STEWARD