Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/11/23

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
531 PM CST Tue Jan 10 2023 ...New AVIATION... .SHORT TERM... (Now through Wednesday night) Issued at 128 PM CST Tue Jan 10 2023 Warmer than normal temperatures continue the next few days with another bout of fog possible tonight. Southerly winds get a little gusty Wednesday ahead of a cold front nearing the county warning area (CWA) late Wednesday night. Temperatures have steadily climbed today with widespread lower 80s as of 2:30PM CST. This despite some fog around the area for a few hours early this morning. These warm temperatures are due to an H5 ridge building overhead behind yesterday`s shortwave. This ridge has really dried us out, as evident by the very dry air on the water vapor loop from GOES-16 and the very low humidity above 600mb on this morning`s sounding from KBRO. The H5 ridge remains overhead tonight and much of Wednesday before breaking down a bit Wednesday evening in response to a shortwave moving through the middle of the country. This shortwave will be responsible for developing an area of low pressure in Oklahoma. Winds increase Wednesday afternoon as the pressure gradient tightens ahead of a cold front. A Wind Advisory isn`t expected at this time due to the lack of a strong low- level jet overhead. Still, gusts between 30 to 35 mph are expected, especially along the coastal counties, during the day Wednesday. Fog will be a concern again tonight thanks to ample surface moisture in place and the expectation of a relatively clear sky. The biggest question tonight will be how long the winds can stay on the calmer side. If the wind remains too elevated, the formation of fog would be incredibly tough with only a low stratus deck likely. It should be noted that the HREF and SREF continue to advertise probabilities of 50 to 60 percent for visibility of less than one mile across the Brooks/Kenedy Ranches, Brush Country, and Rio Grande Plains. On the flip side, the HRRR shows visibility staying at or above 6 miles tonight. As a result, will hold off on any Dense Fog Advisory, but one may be needed later tonight depending on how the wind behaves. As for temperatures, have leaned a little on the warmer side of guidance for high temperatures as we`ve been running a bit too cool during the day. Interestingly, we`ve been running a tick too warm at night, so have leaned a little more on the cooler side of guidance for overnight lows. Even then, well above normal temperatures will continue the next couple of days with upper 50s to middle 60s expected tonight and again Wednesday night. Widespread middle 80s are in the forecast Wednesday with an outside chance at a few locations outside of the Lower RGV making a run at 90! && .LONG TERM... (Thursday through next Tuesday) Issued at 128 PM CST Tue Jan 10 2023 Wind will be the main weather-maker, at least periodically, through the long-term. Model guidance continues to trend a bit cooler for Friday, so we may actually see one day with below- normal maximum temperatures. By the way, by early next week, climatological averages start to tick upward, ever so slightly, from their annual minimums which are reached at the tail-end of December. Another significant warm-up appears increasingly likely by MLK Day and the following Tuesday, with blended guidance showing mid-80s for much of the CWA, which is right in line with the Climate Prediction Center`s latest 6-10 Day Outlook. Rain chances will be hard to come by, with GFS time-height sections for Brownsville remaining rather dry at mid-levels. That being said, have added a mention of "sprinkles" for Thursday, in association with a cold front, for areas east of I-69E in Cameron and Willacy counties. This is consistent with deterministic model (very light) QPF and WPC guidance. As mentioned in previous discussions, this front is not expected to blast through the area, but will be more of an "oozer". 12Z NAM has it slowly sagging through the CWA, from NW to SE, from about 09-18Z Thu, and model consensus is close to this. With N-NNW flow aloft ahead of ridging over the Desert Southwest, the front will usher in a somewhat cooler and much drier airmass. Per the NBM 4.1, dewpoints fall into the 20s and 30s F (except along the immediate coast) by Friday afternoon as the surface high settles in. This may lead to some fire weather concerns on Thursday; see discussion below. Went a little below the NBM for temps Thu night/Friday/Fri night, leaning more toward the NBM 25th/50th percentile values from the probabilistic guidance, which seemed more in line with raw model temps in the mid-60s for Friday daytime. Both nights should feature lows in the 40s, with Saturday morning a bit colder. Going with mid-upper 60s for highs on Friday, as modest cold advection continues, working against clear skies and a dry atmosphere. Ridge axis aloft passes on Saturday, with low-level onshore flow returning by later in the day, allowing temperatures to rise back toward normal. Sunday looks windy, with the GFS quickly tracking a shortwave trough from the Four Corners region toward the Panhandles, leading to surface pressure falls in the Plains. MEX guidance pointing toward a Wind Advisory for the Lower RGV; however, ECMWF is farther north with the shortwave energy. Have kept the blended wind guidance for now, which suggests windy conditions but perhaps not Wind Advisory levels. Weak zonal flow sets up overhead by Martin Luther King, Jr. day (16 Jan), with the aforementioned temps warming up. Next upper trough moves into the Rockies the following day, possibly bringing back breezy conditions. Both GFS and ECMWF hint at another weak frontal passage around the middle of next week. && .AVIATION... (00Z TAFS) Issued at 512 PM CST Tue Jan 10 2023 VFR conditions prevail now with moderate southeast winds and clear skies. Low clouds lie over the cooler nearshore waters. Broad high pressure will remain in control tonight and Wednesday. Model guidance is picking up on an IFR/MVFR fog/low ceiling signal near dawn on Wednesday. Winds will decrease to light tonight but may remain strong enough to preclude denser fog at the TAF sites. Any low clouds would likely come from over the adjacent cooler waters. Thus, a few hours of degraded aviation conditions can not be ruled out during the morning hours of Wednesday. Confidence was not high enough to go with strongly limited TAFs, but will monitor trends this evening for updates by the next TAF set. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 64 83 67 76 / 0 0 0 10 HARLINGEN 63 84 65 78 / 0 0 0 10 MCALLEN 64 87 65 79 / 0 0 0 10 RIO GRANDE CITY 60 91 61 80 / 0 0 0 0 SOUTH PADRE ISLAND 66 77 66 70 / 0 0 0 10 BAYVIEW/PORT ISABEL 64 82 65 75 / 0 0 0 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...54-BHM LONG TERM....80-MB AVIATION...54-BHM
Area Forecast Discussion
National Weather Service Cheyenne WY
539 PM MST Tue Jan 10 2023 .UPDATE... Issued at 530 PM MST Tue Jan 10 2023 Winds have been declining over the last hour or two. Mesoanalysis shows pressure gradients across the Laramie range on the decline also. GOES water vapor satellite imagery indicates that the strong subsidence that ended up just west I-25 this afternoon has also weakened. Therefore, have decided to expire all of the High Wind Warnings on time. A few gusts of 55+ MPH will remain possible for the next three hours or so primarily in WY Zone 117 (South Laramie Range foothills) and near Bordeaux, but could see this extending to parts of I-25 south of Wheatland. Local height/pressure gradients are expected to become negative by morning. && .SHORT TERM...(This evening through Wednesday Night) Issued at 226 PM MST Tue Jan 10 2023 The main concern with this portion of the forecast is when the winds speeds will diminish and snow band potential in Converse and Niobrara counties tonight and early Wednesday morning. Latest water vapor loop was showing strong subsidence over the Laramie Range this afternoon where wind gusts have reached 70 mph. The subsidence has been struggling to push east of the I-25 corridor, but most locations west of the I-25 corridor have reached high wind warning criteria this afternoon. The 750-650mb jet streak will continue to shift east into the Nebraska panhandle during the remainder of the afternoon and early evening. However, there will be limited subsidence in this region and minimal mixing. We are still planning on letting the high wind warning expire at 5pm, but the latest HRRR is showing high winds peaking at Cheyenne around 4pm. Later shifts will need to keep an eye on the cloud cover and subsidence fields to see if this can transpire. After this jet streak moves through, things should begin to settle down after sunset, but those underneath the cloud cover may keep winds mixing for a while in southeast Wyoming. After midnight, the HREF and GFS ensembles including the Global models are advertising a snow band developing over Converse and Niobrara counties late tonight mainly towards 09Z and persisting through at least 15z. This band of snow appears to be associated with good diffluence aloft ahead a shortwave moving through the Intermountain west. There also appears to be an elevated boundary aloft between 700-600mb moving through that region which will undergo some frontogenesis. Not confident on the intensity of this band, due to limited instability of aloft. However, later shifts will need to keep an eye on this in later runs, because the short range models have been trending upwards with snow amounts. As a result, we went ahead and issued a Winter Weather Advisory in the lower elevations of Converse and all of Niobrara counties. The next question will be how far southeast this band of snow transverses late tomorrow morning into the early afternoon. If the bands of snow are intense enough, it may warrant an advisory for portions of the northern Nebraska panhandle. For now, we will see how this initial band evolves. Meanwhile, those locations around Cheyenne and Kimball may get robbed from the bulk of the snow due to the potential for downslope flow. Still looks like some heavy duty snowfall in the mountains. Wednesday night most of the precipitation should move out of the area as high pressure settles in east of the Laramie Range in response to the upper level ridge moving into the area. .LONG TERM...(Thursday through Tuesday) Issued at 226 PM MST Tue Jan 10 2023 A relatively dry, warm, and breezy long term forecast period as a strong ridge develops and remains stationary over the forecast area until Sunday. Saturday we begin to see a pattern change with a brief shortwave pushing through followed by a stronger shortwave. Global models have trended further south, leaving southeast Wyoming and the Nebraska panhandle not in the most favorable spot for rain/snow chances. While the mountains will likely see a few inches of snow due to the upslope flow and increased moisture, the chances decrease for valleys and lower elevations. As the initial shortwave moves through Saturday afternoon, the GFS is showing westerly winds 40 to 50 knots at 700 mb. So, the chance for High Winds is present, therefore trended the winds and wind gusts upward late Friday night through early Sunday morning. The rain/snow chances increase going into Sunday with the second, stronger shortwave trough pushing through. As this is still 5-7 days out, there is plenty of time for the models to shift and change. Temperatures will remain on the warmer side with highs in the 30s to 40s Thursday, increasing in the High Plains to 50s Friday and Saturday. Sunday, as the shortwaves push through and the wind shifts to north-northwesterly, allowing colder air to advect into the area, high afternoon temperatures will drop back to 30s and 40s with the coldest temperatures out west. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 443 PM MST Tue Jan 10 2023 Western Nebraska Terminals: VFR conditions expected during the evening hours with some mid-level clouds. Late tonight/early tomorrow morning CIGs will begin to drop ahead of a storm system. Some light snow is possible during the early morning hours, with periods of moderate to heavy snow and IFR conditions likely by mid to late morning. Southeast Wyoming Terminals: After a windy day, expect winds to ease this evening. Later tonight, clouds will increase across all terminals with lowering CIGs. KRWL will see snow showers develop overnight, with KLAR and KCYS following with snow by the early to mid morning. Expect IFR conditions in falling snow. && .FIRE WEATHER... Issued at 226 PM MST Tue Jan 10 2023 Fire weather concerns will be minimal due to widespread snowfall and higher humidity during the next couple of days. However, more elevated fire weather conditions are possible along the I-80 corridor between Cheyenne and Kimball Friday and Saturday due to lower humidities and gusty winds. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Weather Advisory from 11 PM this evening to 11 AM MST Wednesday for WYZ101-102. Winter Storm Warning until 11 PM MST Wednesday for WYZ112. Winter Weather Advisory until 11 PM MST Wednesday for WYZ114. NE...None. && $$ UPDATE...MN SHORT TERM...REC LONG TERM...LK AVIATION...SF FIRE WEATHER...REC
Area Forecast Discussion
National Weather Service Des Moines IA
519 PM CST Tue Jan 10 2023 ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Tuesday/ Issued at 308 PM CST Tue Jan 10 2023 Key Messages: -Fog across the north Tonight into Tomorrow -Light snow/freezing rain chances north Tonight -Light snow/rain south on Wednesday night into Thursday morning Fog and low stratus has once again developed over northern Iowa this morning, this time still hanging around by early afternoon. However, the fog has finally started to slow its southward plunge and visibilities have slightly improved for some. Unfortunately, there doesn`t appear to be much sign of this going anywhere overnight. Depending on which model you look at, fog and/or low clouds could improve tomorrow morning, or, if you believe the HRRR, could last through Wednesday and into Thursday. As always, it`s tough to say exactly when this fog will disperse, but a subtle increase in winds tomorrow afternoon should help the chances of improvement. Aside from the fog and stratus through the next few days, we also look ahead to a couple of days with lower-end precipitation chances, one to the northern portion of the state tonight and the other to the south on Wednesday night and Thursday morning. Moisture will be the key variable with these two systems as both struggle to find enough moisture to overcome the drier air. As mentioned, the first of these systems will move through tonight, mainly impacting southern Minnesota and Wisconsin. However, those along the Iowa/Minnesota border will also be clipped by this system, resulting in light snow and freezing rain potential within this area. However, this is far from a sure thing due to a stout dry layer just above the surface. This dry layer will make it difficult for any hydrometeors developed higher in the column to reach the surface. However, moisture depth near the surface has slightly increased in depth through the day, increasing the chances for some light freezing drizzle across the north. Regardless, this still remains borderline with both NAM and HRRR soundings being under 1km of saturation above the surface. Should any hydrometeors make it through the low-level dry layer, or should moisture depth over-achieve guidance at the surface, it would not take much to make surfaces slick. Therefore, in collaboration with neighbors, have decided to continue some light PoP chances in the far north. Confidence is low on the southern extent of this, so kept chances north of Highway 20 for now, but will continue to monitor this as models have begun to indicate slightly better chances further south into the state. The second of these two systems will move through late Wednesday night and into Thursday, this time impacting the southern part of the state. The track of this precipitation has wavered some over the last few days, and there has been a good deal of uncertainty amongst long range and short range guidance on the exact location of precipitation. Right now, the most likely location resides across southern and southeastern Iowa, especially given recent short range models zeroing in on this area. The other area of uncertainty resides within the precipitation type. Given current soundings, it appears a warm nose aloft could lead to a brief period of freezing rain as the column saturates. However, cool air quickly takes over, switching precipitation over to snow. In collaboration with neighbors, decided to keep this system as rain and snow for now, but expecting the need for some freezing rain mention should this warm nose become more prominent in future model runs. On the back side of this system, temperatures will cool off a bit on Thursday and Friday, but won`t stay that way long as they warm through the weekend. Similarly, winds will ramp up as the system departs resulting in gusty conditions on Thursday. Looking ahead to next week, long range models show multiple precipitation producers, one towards the beginning of the week and another by mid week bringing more rain and snow chances to the area. && .AVIATION.../For the 18Z TAFS through 18Z Wednesday afternoon/ Issued at 1137 AM CST Tue Jan 10 2023 Fog and stratus have remained persistent across the north today, as KMCW continues to see LIFR conditions. Similar conditions are expected shortly at KALO. Confidence is relatively low in how much improvement will be seen at either of these sites through the day, but would expect some improved visibilities this afternoon before falling again in the evening. KALO is in a more difficult spot, as it looks to be on the edge of expected fog and stratus through today and into tomorrow morning. Therefore, KALO may see occasional improvement as they sit right along the edge, but are expected to be dealing with some form of fog and stratus through tomorrow morning as well. KFOD would be next in line as this fog/stratus pushes south, but is less certain to experience this fog and will continue to monitor for changes. Some low clouds are expected to move in towards the end of the TAF period tomorrow at KFOD. KDSM and KOTM will be VFR through the period. && .AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/ Issued at 516 PM CST Tue Jan 10 2023 Significant categorical restrictions from fog/stratus across northern Iowa is the primary terminal forecast challenge through the next 24 hours. LIFR to IFR conditions are already in place at KMCW and KALO. Recent trends and model guidance suggest little potential for improvement this evening into the overnight hours. The main question is how far south the sub-VFR conditions creep tonight. Maintained mention of VFR conditions at KDSM due to low confidence in the occurrence of low stratus and fog this far south, but will need to be closely monitored and may be considered for future TAF issuances should trends move in that direction. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Dodson/Ansorge AVIATION...Martin
Area Forecast Discussion
National Weather Service Quad Cities IA IL
529 PM CST Tue Jan 10 2023 ...AVIATION UPDATE... .SYNOPSIS... Issued at 235 PM CST Tue Jan 10 2023 Other than some cirrus across the cwa skies were sunny. Mid afternoon temperatures were in the mid 30s north to mid 40s south. && .SHORT TERM...(This evening through Wednesday) Issued at 235 PM CST Tue Jan 10 2023 Forecast message: Dry with above normal temperatures. Tonight: Upper level trough moving into the central Rockies will allow for warm air advection to kick in. Forecast soundings indicate the mid levels in the column moistening up, but the low levels are quite dry. However, at ground level the temperature/dew point spread is close so there is the potential for patchy fog developing later this evening and overnight. Low confidence on dense fog but nonetheless with temps at or below freezing a few slick spots are possible. Lows will range from the mid 20s along Hwy 20 to the lower 30s south. Wednesday: Partly sunny with any lingering fog burning off by late morning. Forecast soundings indicate the low levels still quite dry so no pcpn expected during the day. By late afternoon, a digging trough moves into the central/southern Plains with low pressure along the Kansas/Oklahoma border south of Medicine Lodge, Kansas. Highs will range from the lower to mid 40s north to near 50 in far northeast Missouri. .LONG TERM...(Wednesday night through Tuesday) Issued at 235 PM CST Tue Jan 10 2023 Key Messages 1) Chance for light rain and snow late Wednesday night into Thursday morning 2) Highs mainly in the 40s Sunday into Tuesday with a chance for rain Monday into Tuesday Wednesday Night through Thursday, a low pressure system in Arkansas will be moving NE up the OH River valley region. Latest GFS and now Euro has shifted slightly southeast with the track which brings mainly deformation precip across the southern third or so of the CWA. This system appears to be rather quick-moving and focused for after midnight Wednesday night until about midday Thursday. Wednesday evening may be entirely dry with only some lingering precip in the eastern CWA Thursday afternoon. The bulk of the precip may be confined to a rather narrow band, and where this exactly sets up is unknown at this time. As for ptypes, it appears to be mainly rain mixing with and changing to snow as it moves across the area. QPF amounts have come in lower and range from a hundredth or two along Fairfield to the QCA to Sterling, with around a tenth inch from Memphis MO to Princeton IL. Snow amounts will mainly be under a half inch. While impacts will be limited, it appears that a rain/snow mix will be ongoing during the Thursday morning commute, especially south and east which may have some travel impacts. Thursday, temperatures will be much colder with highs in the 30s and blustery NW winds making it feel even colder. Thursday night through Sunday, dry conditions will prevail as high pressure moves across the region. Friday will be cold with brisk NW winds and AM wind chills in the single digits and teens. Highs will get in the mid 20s to lower 30s, with wind chills only rebounding into the teens to low 20s. A nice warmup is expected over the weekend and early next week as southerly flow behind the high brings 40s back into the area. Monday into Tuesday, models are actually in pretty good agreement in bringing a low pressure system across the region. The current blend has mainly rain for this event with likely POPs focused on the daytime Monday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 517 PM CST Tue Jan 10 2023 Ground fog will remain possible in the next 24 hours, but with high cloud cover expected to continue, there is low confidence on the timing of any fog onset. The HRRR suggests winds will remain very light, and fog waits until tomorrow in the middle of the day to onset. That is a odd time of day, for what should be another mild day in the 40s. For now, I have kept conditions VFR, but will watch trends to see if we need more hours of fog potential. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...Haase SHORT TERM...Haase LONG TERM...14 AVIATION...Ervin
National Weather Service Hastings NE
558 PM CST Tue Jan 10 2023 .DISCUSSION...(This evening through Tuesday) Issued at 439 PM CST Tue Jan 10 2023 -- Key Messages for the entire 7-day forecast (see end of discussion for shorter term forecast details): * This 7-day forecast features MAINLY dry/quiet weather with two quick-hitting systems that could bring at least minor amounts of precipitation: 1) one mainly late Wed afternoon- overnight that bears watching just in case it "over-produces" on snowfall (especially in our south)...2) another one Sunday evening- Monday that very preliminary looks like it could be mainly liquid/rain? * Temperatures over the next 7 days as a whole look to continue the above normal/average trend (mid-Jan avg. highs range mid 30s to low 40s), with most areas well into the 30s/40s on most days and more 50s likely this weekend, especially in our southern coverage area (CWA). Even our overall-coldest day (Thurs) still has highs no worse than low-mid 30s. * Other than a period of modesty-windy conditions Wed evening- Thurs AM (gusts up to around 35 MPH likely), the remainder of the 7-day looks to be fairly "calm" by winter standards, with even gusts on most days no more than 25 MPH. * Peeking JUST BEYOND our official 7-day, there are hints of perhaps another system to watch around next Wed (Jan. 18), but obviously this is fraught with uncertainty at that time range. -- More detailed overview/highlights of the entire 7-day forecast (including ALL discussion of Days 3-7 Fri-Tues): 1) General overview of the large scale upper air/surface pattern and any notable model differences): At least through Day 6 (Monday), the latest ECMWF/GFS remain in pretty remarkable agreement on the large scale upper air pattern. In short, we first see "system #1" affect parts of our CWA tomorrow evening-overnight as it passes mainly slightly to our south. In its wake, we reside under northwesterly flow Thursday before a large-scale ridge gradually transitions into/over the Central Plains Fri-Sat (ushering in a nice warm-up). While Sunday daytime should remain dry/mild, already Sun night-Mon the next quick-moving shortwave trough zips through our region in some semblance (exact track still uncertain) followed by another period of weak ridging/quasi-zonal (west-east) flow Tues. As is typical, the GFS is suggesting a faster arrival of yet another possible system by Tues afternoon/evening, but our official forecast keeps Tues dry (more in line with ECMWF) with the next possible weather- maker holding off until Wed. At the surface, GFS/ECMWF are also in good agreement. As mentioned, other than a period of northerly gusts 30-35 MPH Wed night-Thurs AM associated with system #1, winds should not be a very big deal during the vast majority of the 7-day. The overall-strongest SOUTHERLY winds are likely Saturday, but at least for now gusts are only progged around 25 MPH. 2) Precipitation overview: As mentioned, we have 2 distinct windows of opportunity for at least minor precipitation in the 7-day: 1) one mainly late Wed afternoon-overnight that bears watching just in case it "over- produces" on snowfall (especially in our south)...2) another one Sunday evening-Monday AM that very preliminary looks like it could be mainly liquid/rain (but plenty of uncertainty at that time range). Will cover the shorter term system in more detail below in the "Short Term Detail" paragraphs, so skip ahead for that if interested. As for the second system, all small chances (PoPs) are currently confined to the Sunday evening-Monday daytime time frame. Although plenty of details are yet to be resolved for this one, early indications suggest the mid level low could track similar to slightly farther north than the shorter term one, with warmer temperatures aloft tending to keep precipitation as more rain than snow, along with a non-zero chance for a little freezing rain/ice. However, because this system is still well out in the Day 5-6 range, have kept any mention of freezing rain/ice out of our official forecast for now. 3) Temperature overview: As touched on in the opening bullets, our overall above-normal temperature regime just keeps marching on. While we are not talking seasonably-balmy 60s or anything, we are also not talking frigid highs in the single digits (or worse) or sub-zero wind chills. Just a steady dose of days mainly in the 30s/40s and some 50s likely over the weekend (especially KS zones). As for overnight lows, most every night should bottom out in the teens/20s most places...again slightly above normal overall and certainly nothing out of line for January. Peeking ahead beyond our 7-day forecast into Week 2 (Jan. 18-24), the latest ECMWF ensemble continues to depict an overall slightly above normal regime, with highs mainly 30s in our north/40s south. -- With the main messages/highlights of the entire 7-day outlined above, will conclude with shorter term details focused solely on the next 48 hours/4 forecast periods...with a particular emphasis on the Wed afternoon-overnight system: - Current/recent weather scene as of 345 PM: Despite more high level clouds streaming overhead today, it has again been seasonably-mild by January standards, Although the clouds have kept our KS zones from achieving the upper 50s, snow- free areas of our southern/eastern CWA have managed to reach the low-mid 50s with cooler highs somewhere in the 40s most common over lingering shallow snow cover in our northwest 1/3 or so. Winds today have been seasonably-light, generally averaging around 10 MPH (some slightly higher gusts) from mainly a southerly direction. In the mid-upper levels, short term model data and water vapor satellite imagery confirm broad, quasi-zonal flow over the Central Plains, with our main upstream feature of interest being a shortwave trough currently over southern CA/NV, residing in the southern periphery of a large-scale trough and associated closed low churning off the Pacific Northwest coast. - This evening-overnight: High confidence in continued dry conditions. While the night will start and likely end with a fair amount of continued mid-high level cloud cover, much of the overnight should actually clear out pretty efficiently in between "pushes" of the higher clouds. At the surface, breezes overnight will remain fairly light (only around 10 MPH or less), but direction will gradually turn westerly and eventually northwesterly behind a weak trough axis. While some light haze is certainly possible mainly over areas with continued snow melt in our far north/west-central, the predominant westerly breeze should keep legitimate fog at bay and have kept out of the forecast. These light breezes should also keep temps from "tanking" too far (despite a period of clearing skies) and have low temps aimed no lower then 24-28 most areas (perhaps a bit colder in our typical colder spots such as Ord). - Wednesday daytime (through 6 PM): The majority of the day (especially pre-3 PM) carries high confidence in remaining dry, although clouds will thicken/lower with time in the mid-high levels, and we will likely see lower cloud development by late afternoon. In the mid-upper levels, the main shortwave trough will start the morning over CO, but by sunset will have reached the central/southern KS, strengthening as it does so with a closed low developing at 500 millibars. Through sunset, the vast majority of the CWA probably stays dry, but have low PoPs (mainly 20-30 percent) in most areas mainly 3-6 PM as the leading edges of light-rain-changing to snow could get underway in our far west, with more spotty light rain showers perhaps developing farther east within mainly the southern half of our CWA. Do not anticipate any possible wintry precip travel issues pre-6 PM at this point. Temp-wise, it will be a good 5-10 degrees cooler than today thanks to thicker clouds and weak cold air advection behind a cold front. Nudged highs up slightly south and down slightly north, yielding a range from mid 30s far north to around 40 central (Tri Cities) to upper 40s south (mainly KS). Winds will gradually increase out of the north as the day wears on, averaging sustained 10-20 MPH/gusts around 25 MPH by late afternoon. - Wednesday evening-overnight (after 6 PM): For sure, the 6 PM-4 AM time frame is currently our #1 concern of the entire forecast package. In the basics of the mid-upper levels, the closed low that starts the evening over central KS will steadily depart/track eastward into central MO by sunrise Thurs. As has been the case for several forecast cycles, the main low will slide slightly to our south, but perhaps NOT QUITE as far south as it appeared a few days ago. This means that precip chances especially near/south of the KS line have increased now versus previous forecasts, with even some "likely" 60+ percent introduced with this forecast. Meanwhile, much lower PoPs only 20 percent tops reside in our far north (with middle areas including Tri Cities remaining a bit of a middle ground/question mark). Without going into TOO MUCH detail for the 3rd forecast period, here are some high points: - our official forecast did not change much with regard to snow totals, calling for evening-overnight accumulations of generally one-half inch or less for most of our Nebraska zones (especially south of I-80), and with amounts closer to 1" in our KS zones. - This falls pretty well in line with most larger scale models such as NAM/GFS/ECMWF. However, am a bit concerned by last few HRRR runs, which are more aggressive in developing a more concentrated deformation/mesoscale band from around the Tri Cities and south-southeastward. Should this materialize, cannot rule at at least snowfall exceeding expectations, with a quick 2-3" of slushy, wet accumulation not out of the question. Unfortunately, confidence is still too low at this time range to accurately place such potential for these higher amounts. - Expect a pretty quick transition from rain to snow, but a BRIEF period of freezing rain probably cannot be ruled out (especially in our southeast zones). However, have kept this out of the official forecast, Hazardous Weather Outlook etc. - Despite the west/slushy nature of the snow, some visibility reductions could easily occur for up to a few hours in any steadier bands as northerly wind gusts increase to 30-35 MPH. - No matter how little (or locally how much?) snow falls, even the more aggressive models are in good agreement that the back (north) edge of the snow band should depart our far southeastern CWA by around 4 AM or so. - In summary: there is a non-zero chance that this event could still "over achieve" and even prompt a shorter-notice Winter Weather Advisory, but at least for now the minimal snow amounts do not justify one. Low temps Wed night aimed low 20s north to mid 20s south...can`t go any colder given steady winds/plentiful lingering clouds. - Thursday daytime: This will almost surely be the overall-coldest day of the next week. Although any lingering snow/flurries should be long gone by sunrise, especially the morning will probably feature quite a bit of lingering lower clouds, with in theory more sunshine breaking out in the afternoon (not a sure thing). Winds will remain somewhat blustery in the morning (gusts 20-30 MPH) but will gradually ease in the afternoon as a surface high pressure axis slowly eases in from the north. High temps aimed from low-mid 30s in most of our Nebraska zones, to as warm as the upper 30s-low 40s in our KS zones and Furnas County area, but should a fresh coating of snow be on the ground from Wed night then these values could be a bit optimistic. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 538 PM CST Tue Jan 10 2023 VFR conditions should continue throughout the TAF valid period. We do expect a weak storm system to move into the region late Wednesday afternoon, but more likely just beyond the end of the TAF valid period Wednesday evening. Although a few flurries or sprinkles can not be ruled out Wednesday afternoon, the better chance for perhaps light snowfall accumulation will be Wednesday evening just beyond the 24 hour TAF valid period. The wind will be light through Wednesday morning, generally out of the west this evening and then northerly by Wednesday morning. North winds will increase Wednesday afternoon gusting 20 to 25 mph by late afternoon. Clouds bases should remain above 5000 ft agl throughout the period, but will likely fall quickly just beyond the end of the TAF valid period Wednesday evening. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ DISCUSSION...Pfannkuch AVIATION...Wesely
Area Forecast Discussion
National Weather Service Green Bay WI
619 PM CST Tue Jan 10 2023 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Wednesday Issued at 237 PM CST Tue Jan 10 2023 The latest RAP analysis and satellite/radar imagery show a trough of low pressure extending northwest to southeast across Wisconsin early this afternoon. Other than the Fox Valley and Lakeshore, visibilities haven`t improved much so far today. Areas across central WI have seen visibilities below 1 mile consistently, and some locations have been steady in the 1/2 to 1/4 mile range. The surface obs may have a low bias, however, as area webcams show only patchy dense fog across that area. Have considered a dense fog advisory, but considering the patchy nature as shown by webcams, have decided to highlight the threat in a SPS. Ice accumulation sensors are also ticking off light ice accretions, which could also indicate freezing drizzle at times. Looking upstream, a shortwave trough is moving across the Dakotas and poised to enter the area late tonight. Forecast concerns include dense fog potential and potential for a light wintry mix. Tonight...The weak low level trough of low pressure will gradually lift north across the state. If visibilities do not improve much this afternoon, it`s quite possible that areas across central to north-central, and parts of far northeast Wisconsin will need a dense fog advisory. Some icing is possible on untreated roads and surfaces as temps fall below freezing, particularly over far northeast WI where light upslope flow will continue at least through the evening. Then attention turns to precip chances as disjointed shortwave energy moves into the region from the west. Higher resolution models have shifted a narrow band of light precip in the warm advection zone further south and target parts of central WI and the Fox Valley late tonight. Forecast soundings indicate concerns about deep saturation with ample mid-level dry present. If precip does develop, enough warm air may surge north to introduce wintry mix of sleet and freezing rain in with snow. Slippery roads could develop if this were to occur. Temps will remain relatively steady and range from the mid 20s to low 30s. Wednesday...Weak warm advection will cause any light precipitation to lift north across the region. Thermal profiles would continue to suggest a light wintry mix is possible across central and east-central WI before surface temps rise above freezing. Precip accums have gradually diminished over the past several runs and now only provide up to a half inch of snow, highest across far northern WI. Uncertainty regards placement and amounts of the precip band is too high to issue any headlines. But will mention scattered slippery spots on roads are possible in the HWO. Highs will be ranging through the 30s. .LONG TERM...Wednesday Night Through Tuesday Issued at 237 PM CST Tue Jan 10 2023 Main highlights for the long term will be a brief bout with lake effect snow Thursday night over the north, a quiet weekend, then watching a system for early next week that looks to bring a wintry mix. Temps will remain above through the period. Wednesday night into Thursday night...continued cyclonic flow, weak shortwave energy along with an approaching stronger shortwave will keep skies cloudy, with small chances for some light precip, especially over north central WI. As colder air advects into the area, delta Ts will climb into the teens over Lake Superior. With a favorable N/NNW fetch, lake effect snow showers and flurries are expected Thursday afternoon into Thursday night. Amounts look to be on the light side, with up to an inch or two in the favored locations in Vilas Co. Little to no accumulation is expected elsewhere. North winds will increase on Thursday as the low pressure system to our south/east strengthens. Gusts of 20-30 mph are likely inland, with higher gusts closer to Lake Michigan. Temps won`t drop much Wednesday night due to the clouds, with most spots seeing lows in the mid 20s to low 30s. Another day with a small diurnal range on Thursday, with highs only climbing into the upper 20s and 30s. A push of colder air, along with some possible partial clearing, will bring colder temps Thursday night, with lows in the teens and 20s. Rest of the long term...any lingering lake effect snow will wrap up Friday morning as drier air works into the western Great Lakes. Will be challenging to get rid of the lower clouds initially, but partial clearing is expected for parts of the area especially by Friday afternoon. However, a mid-upper cloud deck will be increasing across the area which will limit the amount of sunshine we see. High pressure slides over the region on Friday then east of the area this weekend. This will set up a slow but steady push of WAA. While it looks like we will lose the low clouds for a time, the mid-upper clouds look to be present for much of the late week and weekend. Temps will moderate into the weekend, with above normal temps prevailing. Some spots could climb to/above 40 degrees Sunday into Monday. Friday night is still looking like the coldest with the best chance for some clearing and the cold air still in place. The quiet weather will come to an end on Monday as storm system gathers strength in the Plains and heads into the Great Lakes Monday night into Tuesday. The system will not have a lot of cold air to work with, but just enough cold air on the north/west side to bring some precip type issues into the forecast. Models vary on track of the low and therefore temps/precip types. Will continue to monitor trends as the system gets closer, but this will be the next more significant weather maker for the area. && .AVIATION...for 00Z TAF Issuance Issued at 617 PM CST Tue Jan 10 2023 Low clouds, fog, and light precipitation will be the primary aviation weather concerns this evening. Anticipate little change in ceilings or vsbys during the evening. Scattered light precipitation is likely across the north--mainly in the form of DZ/FZDZ based on surface temperatures. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM.....MPC LONG TERM......Bersch AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
943 PM EST Tue Jan 10 2023 LATEST UPDATE... Update .UPDATE... Issued at 939 PM EST Tue Jan 10 2023 Going forecast is on track. Skies have cleared over the southwest cwa but high clouds continue a steady march toward the state. Expect mostly cloudy overnight. Visibilities have fallen to around 5 miles in the clearing area which is also were we saw some rain/snow today. I don`t expect vsbys to fall too much farther given the clouds moving in. Latest HRRR continues to show a very brief period of light rain Wednesday morning but freezing rain remaining west of the cwa. && .DISCUSSION...(This evening through next Tuesday) Issued at 213 PM EST Tue Jan 10 2023 - Risk for Fog Tonight We will add patchy fog to the forecast for tonight. Satellite trends show the clouds trying to thin out over the region. Forecast models show a potential for a period of scattered cloud cover this evening. Already the visibilities are slightly restricted in places. South to southeast zones saw measurable precipitation today...which will keep the moisture high near the ground level there. As we scatter out with the cloud cover in those regions and we develop some radiational looks like at least patchy fog could form. The latest HRRR shows the eastern zones developing fog tonight with visibilities under a mile. Surface temperatures will end up near freezing so if fog does form...we will need to monitor the potential for icy spots on the roadways. - Potential for light rain/drizzle Wednesday Shallow warm and moist air advection arrives Wednesday as a shortwave moves in from the west. Good saturation in the low levels is noted with some lift. This may allow for light rain/drizzle to form. At this time surface temperatures look like they will be just above freezing when the potential for precipitation will be on the increase. Thus we will feature only liquid precipitation. - Low Risk for impactful snow Thursday into Thursday evening The models are in decent agreement with the low track for Thursday into Thursday evening...tracking it northeastward through OH. We will be in a favorable location for snow to accumulate. However the thermal profiles are initially warm and this system does not have very cold air to work with. Thus how much we cool off Thursday is somewhat uncertain...especially since the temperature fall will be partly driven by the precipitation intensity. However forecast soundings show enough cooling to support a period of snow on the backside of the departing storm with Thursday afternoon/evening being the most likely window for this to happen. Ground temperatures are likely to be relatively melting on roads and sidewalks looks likely to happen. This will lead to slushy accumulations where the band of steadiest snow falls. At this time...the Lansing to Jackson region is shown to be in the most favorable location for accumulations as that is the region in our CWA shown to see the strongest mid level FGEN. If this system is able to tap slightly colder air...then the impacts would increase. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 645 PM EST Tue Jan 10 2023 IR loop shows clearing over southwest Lower trying to move east. We should see some progress with this south of I-96 tonight. However, that`s also an area that saw a little bit more rain/snow today. So, if skies clear, then we`ll likely see some fog develop, especially at AZO/BTL/JXN. Expect MVFR conditions overnight, either due to cigs or fog restricting visibilities. Toward morning, weak low pressure will approach and short range models are hinting at the potential for a brief period of light rain. Don`t think it will amount to much and covered it with a VCSH comment. && .MARINE... Issued at 213 PM EST Tue Jan 10 2023 The wave of low pressure that tracks eastward through the region Thursday into Friday will generate some higher winds and waves. The highest waves are forecast on the backside of the system due to the deeper mixing that occurs with cold air advection. A small craft advisory will likely be needed then. Otherwise a relatively weak pressure gradient regime is forecast to prevail. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...04 DISCUSSION...MJS AVIATION...04 MARINE...MJS
Area Forecast Discussion
National Weather Service Indianapolis IN
915 PM EST Tue Jan 10 2023 .Forecast Update... Issued at 915 PM EST Tue Jan 10 2023 No significant changes required to going forecast. Mid and high cloud will continue to steadily increase overnight ahead of our next low pressure system, which will bring drizzle, low clouds, and a few showers to the area on Wednesday. Min temp forecast is in good agreement with latest guidance, as the increasing cloud cover along with increasing warm advection will limit diurnal cooling, and mid 30s to around 40 is a good target for the area. Latest high res guidance is indicating some potential for drizzle a little earlier than what is in grids, but this would be of minimal consequence if it occurred with no threat of freezing, so going forecast has it covered adequately. && .Short Term...(This evening through Thursday) Issued at 306 PM EST Tue Jan 10 2023 Rest of Today Generally clear skies are found across Indiana this afternoon within broad subsidence on the backside of a departing shortwave. The trend will be reversed, however, as a weak shortwave quickly approaches from the west. High cirrus clouds are expected to begin increasing in coverage later this afternoon and into tonight. Cirrus should remain thin enough for a sharp inversion to develop shortly after sunset this evening. Tonight Low-level moist warm advection should commence overnight as winds turn southerly. Aloft, a more southwesterly component to the wind will allow warm but dry air to build in above 850mb. BUFKIT soundings show a nearly saturated layer below 850mb after 12Z, with a pronounced mid-level inversion and dry layer - an ideal drizzle sounding. As such, drizzle will be included in the forecast after about 12z. Wednesday and Wednesday Night Model soundings remain relatively the same through the day Wednesday with a pronounced low level inversion and dry mid-levels. Two inversions actually are present within the soundings, one in the near-surface layer and another centered at around 850mb. There exists some divergence within the model soundings at this point. Higher resolution models tend to retain the near-surface inversion while the GFS, for instance, erodes it fairly quickly allowing temperatures to rebound to about 50 degrees. The solutions with the strong, more long-lived inversion keep surface temperatures as much as 5C cooler. Will lean towards the stronger inversion scenario given the light surface winds, strong low-level WAA above 925mb, and dry air aloft. Will keep high temps a bit below guidance given the idea of more persistent low stratus, drizzle, and light winds. By Wednesday night, an upper-level trough and associated surface cyclone will approach the Ohio River Valley. Favorable jet dynamics, isentropic lift, and an increasingly saturated column will lead to widespread rain developing late Wednesday night. Thursday As the center of the surface low swings through, a brief period of instability may develop within the system`s warm sector. The greatest chance of this occurring appears to be mainly across our far southern counties and down towards the Ohio River, given the likely track of the surface low through the Indianapolis area. Guidance generally shows weak CAPE, but a few hi-res models such as the RAP give upwards of 800 J/kg with a more wrapped up low. Guidance shows plenty of shear exists with robust flow aloft, near 50kts through 0- 6km. The environment will also be characterized by lapse rates just slightly steeper than moist adiabatic. Severe weather is not currently anticipated, however, as most models show the near-surface inversion persisting into Thursday as well, albeit not as strong. South towards the Ohio River, outside of our forecast area, the inversion has the best chance of eroding away. In response, the SPC has included areas just south of our CWA within a Marginal Risk for severe storms. Given the parameters mentioned above, storms within the risk area to our south have a low threat for small hail and marginally severe wind gusts. && .Long Term...(Thursday night through Tuesday) Issued at 306 PM EST Tue Jan 10 2023 The long term period will start out Thursday night with a system slowly making its way out of the area. With the cold front having made it`s way through the area during the day Thursday, temperatures overnight will drop into the 20s as that colder air advects in from the N and NW. Moisture will remain in the area on the backside of the low, so there is a good chance of rain transitioning to snow Thursday night into early Friday with light accumulations possible. One uncertainty will be when precipitation ends with this system and the speed at which the surface low exits the region. While the surface low will push off to the NE, a secondary upper low will form and track ESE towards the mid-Atlantic states. This will allow upper ridging and a surface high to settle in over the Ohio Valley through the weekend. The precipitation could continue into the day Friday with that backside moisture, especially if the surface low slows down. Parts of central Indiana could even see scattered snow in the afternoon with a potential for some Lake Effect precip under the northerly flow, but confidence remains low at this time. For now have chance PoPs through Thursday night with only slight chance of PoPs Friday. All precipitation chances will confidently be gone by late in the day Friday as subsidence and dry air with the high pressure strengthening. Otherwise, dry weather and near normal temperatures in the upper 30s will persist for much of Friday and into Saturday. As the high progresses eastward, southerly flow will return to the region and temperatures will quickly return to the 40s and 0s for the start of the new week. Another system will move through early to mid next work week, so could see another decent chance at some rain and possibly thunderstorms. At this time there is a bit of variability between models with this system so details are uncertain beyond the chance of precipitation. && .Aviation...(00Z TAF Issuance) Issued at 606 PM EST Tue Jan 10 2023 Impacts: * Widespread IFR ceilings and MVFR visibilities expected Wednesday midday onward in drizzle and possible showers. Discussion: VFR conditions are expected throughout the night into early Wednesday morning. A broad area of warm moist advection ahead of a weak low pressure system will bring low ceilings, fog, and drizzle, along with possibly some showers, into the area late morning into midday Wednesday, when conditions are expected to rapidly deteriorate to IFR and remain IFR throughout. Winds will be below 10KT throughout the period, generally becoming more southerly with time. && .IND WATCHES/WARNINGS/ADVISORIES...None. && $$ Update...Nield Short Term...Eckhoff Long Term...KH Aviation...Nield
Area Forecast Discussion
National Weather Service Marquette MI
635 PM EST Tue Jan 10 2023 .SHORT TERM...(Through Tonight) Issued at 259 PM EST TUE JAN 10 2023 Water vapor imagery and RAP analysis show a shortwave moving e across the western Great Lakes/Ohio Valley. Northern extent of this wave has aided some very light snow across portions of Upper MI today from the Keweenaw ese into the eastern fcst area. So far, have not seen any reports of -dz/-fzdz, but would not be surprised if some has occurred, especially in areas across the w half where ese winds are an upsloping wind direction. Fcst soundings have been showing moisture depth not as deep in that area with cloud deck in temps that don`t reach -10C. With the low sun angle and low stratus across the area, temps haven`t changes much today with current readings in the mid 20s to lwr 30s F. Tonight, another shortwave, currently over eastern MT/southern Saskatchewan, will move e, reaching MN Wed morning. As a result, ongoing weak waa/isentropic ascent will continue tonight and tend to increase a bit. Fcst soundings generally suggest deeper moisture across the northern and eastern fcst area and shallower moisture to the sw. There is variation though at times across the area. As a result, there will continue to be times tonight where moisture depth does not extend to temps of -10C or lwr, especially toward the MI/WI stateline. While that area should be more likely to see ptype of -fzdz, will simply cover the fcst area with a mix of -sn/-fzdz/-dz. Models have tended to overdo the QPF today, though it was only fcst to be very light to begin with. That will probably be the case again tonight, and opted to shave qpf down a bit. Expect any snow accumulation to be less than 1 inch, really not much more than a dusting, as dgz is not in the pcpn production layer. A thin glaze of ice will be a possibility if -fzdz develops/expands. Given the continued stratus deck, temps won`t drop much, if at all, from current readings. In fact, very slight warming may occur thru the night. .LONG TERM...(Wednesday through Tuesday) Issued at 335 PM EST TUE JAN 10 2023 Key Messages: -Wintry mix continues Wednesday -Light lake effect snow Thursday and Friday -Friday into weekend dry, could see some sun despite cold Saturday -Models hinting at a low passing through early next week Wednesday, wintry mix persists from the overnight period as a weak low pressure in Wisconsin and PVA from weak 500mb shortwaves provide forcing for weak precipitation. A break in the wintry mix will have to wait until at least Thursday, as model soundings keep some areas of the Upper Peninsula in a sufficently warm surface layer that some liquid could fall. Even in areas that are subfreezing, the saturated portion of the profile is below the DGZ, which could lead to a lack of ice nucleation and resulting freezing drizzle instead. By late Wednesday, northwesterly flow resumes at most levels, leading to cooler air and a switch to mostly- to all-snow. The 12Z ensembles have pulled away from a solution that would have brought a weak low center along the northern shore of Lake Superior, though with persistent northerly flow, air aloft is cooling enough to reintroduce lake effect snow through Friday. The intensity of snow is limited, as some drier air aloft limits the depth of precipitating clouds. 850mb temps fall below -10 C in the west half Thursday afternoon, with the east half reaching that temperature overnight into Friday. Ridging aloft and surface high pressure moves into the region Friday night. The subsidence from this will serve both to dry out the surface layer and cut off the cold advection that was feeding the lake effect delta-T`s, ending the snow for the UP. Should clouds really break up Friday night, Saturday morning`s low could be well into the single digits for the interior west, though temperatures should rebound for the high especially if the sun comes out. For the late weekend and beyond, model solutions diverge significantly, but the ensembles are keying in on a low pressure passing in the vicinity of the Upper Great Lakes in the Tuesday time range, and with NAEFS PWAT percentiles above 97.5, it will be worth monitoring as the next potential precip-generating system. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 632 PM EST TUE JAN 10 2023 Abundant low-level moisture will remain in place across the area during this fcst period. As a result, expect IFR/LIFR cigs to prevail at IWD/CMX/SAW. BR and some light pcpn are also expected at times, especially at CMX/SAW where ese/se winds are upsloping. So far, pcpn has been in the form of -sn, but expect pcpn to mix with or change to -fzdz at times. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 335 PM EST TUE JAN 10 2023 Southeasterly winds are gusting to 25 knots over the east 2/3 of Lake Superior this afternoon with a low pressure passing south of the lake. Overnight, gusts briefly reach 25-30 knots, but diminish below 20 knots Wednesday morning. Winds remain under 20 knots across the lake until Thursday afternoon, as gusts reach 20-25 knots. With a ridge approaching Friday, winds in the west half drop below 20 knots Friday morning and in the east half Friday afternoon. Winds remain below 20 knots for the remainder of the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...GS AVIATION...Voss MARINE...GS
Area Forecast Discussion
National Weather Service New York NY
926 PM EST Tue Jan 10 2023 .SYNOPSIS... A weak cold front moves south of Long Island tonight followed by high pressure building across eastern Canada and northern New England into Wednesday. The front lifts back to the north as a warm front Thursday night, followed by a cold frontal passage Friday morning. High pressure builds slowly in from the west over the weekend. Another frontal system approaches early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Forecast is on track with only minor changes needed to reflect current conditions. An upper trough tracking across eastern Canada will send a weak cold front across the area this evening. At the same time, a southern branch shortwave trough will pass to the south and off the Mid Atlantic coast. The latter is providing nothing more than a mid level cloud deck, which is passing over top some stratus at the base of 4-5 kft inversion. Consensus begins to clear skies out after midnight as high pressure builds south and east from eastern Canada. However, the HRRR and RAP have done particularly well with the lower cloud deck and indicate this could hang on through Wednesday morning. While not planning be that aggressive, will be slower than the consensus with any clearing late tonight. Preference was toward the warmer end of the guidance due to the cloud cover with lows ranging from the lower 20s inland to the lower 30s across the NYC metro. This is a few degrees above normal. WNW winds will veer to the NE overnight at less than 10 mph. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Another strong PAC system races east across the country Wednesday into Wednesday night with overrunning clouds working in from the west in the afternoon and nighttime hours, while low-level warm advection ensues at night as winds veer to the E/SE. The latter will allow for low clouds to work in from the east of the Atlantic. Wednesday should start off with some sun, however, there is a small chance that some of the stratus overnight Tuesday lingers through day. Highs will be a tad cooler and closer to normal Tuesday, with around 40 inland and the lower 40s at the coast. There is a decent signal of enough moistening in the low- levels along with weak low-level lift for perhaps some light rain/drizzle and/or light snow at the onset (toward daybreak Thursday), mainly north and west of NYC. Should the cold air be deep enough for any light snow at the start, it is not expected to accumulate with temperatures warming through the night. The warming boundary layer also supports light rain/or drizzle at the changeover. The one caveat here is whether the dry air aloft (no ice crystals) keep this is all liquid with a small chance for patchy freezing rain or drizzle well north and west of the NYC metro. This would be real brief and confidence for this scenario is low. Lows Wednesday night will be around 30 well inland, to the mid and upper 30s at the coast. However, these lows will be achieved early in the evening. && .LONG TERM /THURSDAY THROUGH TUESDAY/... High pressure will continue to retreat into eastern Canada on Thursday as a frontal system approaches from the west. With a warm front/stationary front to our south (which may have a tough time working through the region during the day Thursday) and onshore flow under mostly cloudy skies, temperatures will be in the middle 40s to lower 50s. The main change with this forecast is that models for the most part have sped up the timing of the fronts. Light overrunning moisture makes its way into areas north and west of New York City Thursday morning. There may be enough cold air at the start for some snow, or a rain/snow mix across mainly northern and western Orange County and extreme northern Fairfield in Connecticut. However, it is expected to change to plain rain everywhere by the late morning into the early afternoon. Little, if any accumulation is expected. Precipitation will continue to overspread the area Thursday from west to east into Thursday night. A period of moderate to heavy rain is possible with the approach of the cold front Thursday night and as an area of low pressure over the eastern Great Lakes slowly strengthens. Additionally, a brief period of windy conditions is possible. The NBM was showing nearly a 30% chance of gusts near 40 mph for KJFK after midnight on Thursday night. The cold front will push offshore Friday morning. The GFS is a quickest with the cold front, while the ECMWF doesn`t push the cold front through until late Friday afternoon. So, there is still some uncertainty with the cold frontal passage, and the front could push through as late as Friday afternoon. Additionally, the deterministic models have backed off on the development of a low pressure system along the frontal boundary for Friday into Saturday as the upper trough does not negatively tilt until after it pushes off the East Coast. However, given all the uncertainty, kept a slight chance of precipitation Friday night into Saturday. High pressure builds in for the weekend, with cooler temperatures, but still above normal for this time of year, with warming expected from Monday into Tuesday as an upper level ridge builds over the area. The next frontal system possibly affects the area next Tuesday. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... A weak cold front passes through the terminals tonight. High pressure then builds in from north overnight into Wednesday. VFR. A strato cu deck 3500ft to 4000ft will persist until around 07Z at the NYC metro terminals, then clouds become scattered to few. Winds NW to N to light and variable continues overnight. Wednesday winds will be NE, becoming E during the afternoon, less than 10kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... No unscheduled amendments. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .Wednesday night...VFR. .Thursday morning...Mainly VFR, possibly becoming MVFR along the coast. .Thursday afternoon and night...MVFR or lower possible in rain or drizzle. LLWS Thursday night into early Friday morning. .Friday...early morning MVFR becoming mainly VFR. NW winds G20-25kt possible. .Saturday...Mainly VFR. N-NW winds G20-25kt. .Sunday....VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/ && .MARINE... Minor adjustments were made to winds and gusts to reflect current conditions. Sub-SCA conditions are forecast on the waters through Wednesday night as high pressure builds across eastern Canada and New England with NE winds veering around to the E/SE around 10 kt. A period of SCA is expected late Thursday night into Friday as a frontal system impacts the waters, with gales possible on the ocean. Peak wind gusts are expected late Thursday night, just prior to and just after the cold frontal passage. Thereafter, winds diminish. Waves on the ocean build late Thursday night into Friday morning, peaking at 6 to 11 ft on the ocean waters late Thursday night into Friday morning. Waves then slowly diminish into the weekend, but remain above 5 ft through then on the ocean. Waves of 5 to 7 ft are possible across the eastern sound zone, falling below 5 ft by late Friday night into Saturday morning. && .HYDROLOGY... A period of moderate to heavy rain is possible late Thursday night. However, with a quicker moving frontal system, slightly less rainfall is expected. Minor nuisance flooding is still possible. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JP/DW NEAR TERM...MET/DW SHORT TERM...DW LONG TERM...JP AVIATION...MET MARINE...JP/MET/DW HYDROLOGY...JP/DW
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
424 PM MST Tue Jan 10 2023 .DISCUSSION...(This Evening Through Tuesday) Issued at 203 PM MST Tue Jan 10 2023 20z surface analysis had lee trough from central MT into southeast MT. Back door cold front from central ND into northeast NE. Water vapour depicted weak shortwave over western SD with weakening weak radar returns over the CWA, hardly reaching the ground most locations. Energy spinning into the west coast main forecast concern in the near term. - Compact shortwave will bring band of snow to the far southwest overnight into Wednesday - Upper ridge brings unseasonably warm weather end of the week Tonight/Wednesday, shortwave over central CA will race into eastern CO/southeast WY. Compact surface low develops over central WY with tight low level baroclinic zone just northeast of it from northeast WY into southwest SD. Weak surface high building into the Dakotas will further tighten thermal gradient tomorrow as low clouds/fog slip southwest onto the western SD plains. Moderate frontogenetic forcing ahead of surface low supports a band of moderate snow over far southwest southern Campbell County with lighter amounts stretching into the southern Black Hills. 12z ECMWF EFI paints potential as well as 12z SPC HREF/latest HRRR runs. Should see at least 2-5" of snow late tonight/Wednesday morning over southwest southern Campbell County with 1-2" stretching southeast into far southwest Fall River County. Banded nature of snow will create strong accumulation gradients, so later trends will need to be closely watched. Temperatures will be near guidance. Thursday, seasonally cool. Friday/Saturday, upper/thermal ridge forecast by all guidance with 60-80th percentile forecast highs. This translates to widespread 40s/50s with a few 60F readings on the lee side of the Black Hills possible. Pseudo-split upper flow then develops Sunday into next week with some pops here and there as well as slightly above normal temperatures per ensemble trends. && .AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening) Issued At 422 PM MST Tue Jan 10 2023 Mostly VFR conditions are expected at the TAF period. Some light precipitation may be possible this afternoon for parts of northeast Wyoming and far western SD. Some fog will begin pushing into northwestern SD overnight and may bring MVFR/IFR conditions in any area with fog. Light snow will push into NE WY and far SW SD after 08z tonight, although snow/visibility impacts should remain south of KGCC/KRAP. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...Winter Weather Advisory from 11 PM this evening to noon MST Wednesday for WYZ055. && $$ DISCUSSION...Helgeson AVIATION...Eagan