Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/22/22

Area Forecast Discussion
National Weather Service Dodge City KS
439 PM CST Mon Feb 21 2022 ...Updated aviation section... .SHORT TERM...(This evening through Tuesday) Issued at 224 PM CST Mon Feb 21 2022 A cold front is moving southward across the area this afternoon. The high at Hays has already been reached for the day and falling temperatures are likely for the rest of the afternoon, as a large region of intense 850 mb level cold advection continued a southward trajectory across nw KS into CO. A warm nose of air in a downslope environment will continue to promote rising temperatures across the southernmost reaches of the DDC forecast area, with upper 70s still likely by the late afternoon hours. Interestingly, locally at DDC, the HRRR shows about a 15-20F degree drop in temperature (mid 70s to mid 50s) between 4 and 5 pm this afternoon, coincident with the frontal passage and declining sun angle. Attention turns Tonight to apparent temperatures by early Tuesday morning. There already is a wind chill advisory across roughly the northern half of the forecast area as temperatures plunge behind the cold front and north east winds gain strength overnight into the 20 knot and up range, sustained. Medicine Lodge could see a drop from as warm as 80 degrees this afternoon, to freezing by midnight. The wind chill advisory are still looks good, and will run through late morning Tuesday. A minor adjustment to increase a county or two can`t be ruled out yet with 00 model runs coming up this evening. The true cold air continue to settle into the area on Tuesday night into Wednesday. Overwhelming model consensus support highs reaching the 20s over most of the area with a minority of the mesoscale (NAMBC/HiResARW) supporting even colder, maybe under stratus, temperatures across the northern third to half of the areas, relegated to mid/upper teens. The current forecast represents the colder solutions pretty well. .LONG TERM...(Tuesday night through Monday) Issued at 224 PM CST Mon Feb 21 2022 Currently drawing up another wind chill advisory to cover the period from middle of the evening Tuesday though mid morning Wednesday as combined temperature (probably colder this night) and surface wind drive apparent temperatures to around the -15 degree and colder threshold, area - wide. February normally speaking is a tale of 2 halfs with respect to record minimum temperatures. The 1st half (we`ll say through the 16th) historically has lows from -10F to -26 F, while the second half of the month (17th onward) ranged in the negative single digit and positive single lows. At this point the fifth percentile NBM forecast, which might be the coldest we could expect is -4F and all of the model and MOS guidance right now is well above that statistically, where lows around 1 above are near the 50th percentile. Still the apparent temperatures will be significant, probably pushing or exceeding -20F for a period early in the hours before sunrise Wednesday as northeast winds persist from the but winding down still to around 10 knots at sunrise. From a model perspective, looking at lows though the week, it`s clear the arctic air settles in over the high plains and will be quite slow to modify/erode. For instance the ECMWF MOS and daily Raw Model consensus output all show single digit lows through Friday morning , and still quite cold teens into the weekend. Likewise, winter like highs moderating upward toward freezing through the "workweek" before a trend to more normals highs is possible by the upcoming weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 436 PM CST Mon Feb 21 2022 The strong cold front will continue to sag south with high pressure building across western Kansas. This will lead to the strong northerly winds to continue through the overnight period. Some low clouds are expected to filter into the HYS terminal overnight with a few hour period of low clouds possible around the DDC terminal. Otherwise expect VFR conditions. && .PRELIMINARY POINT TEMPS/POPS... DDC 6 22 1 24 / 0 0 0 10 GCK 6 21 0 23 / 0 0 0 10 EHA 10 26 3 26 / 0 0 0 0 LBL 9 27 1 25 / 0 0 0 10 HYS 5 18 -1 21 / 10 0 0 10 P28 13 28 4 27 / 0 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... Wind Chill Advisory from 2 AM to 11 AM CST Tuesday for KSZ030- 031-043>046-063>065. Wind Chill Advisory from 9 PM CST /8 PM MST/ Tuesday to 10 AM CST /9 AM MST/ Wednesday for KSZ030-031-043>046-061>066-074>081- 084>090. Red Flag Warning until 6 PM CST /5 PM MST/ this evening for KSZ061>063-074>081-084>090. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Hovorka42
Area Forecast Discussion
National Weather Service Grand Rapids MI
756 PM EST Mon Feb 21 2022 LATEST UPDATE... Update .UPDATE... Issued at 756 PM EST Mon Feb 21 2022 We (Brandon and I) have decided to add Muskegon, Kent and Ionia Counties to our Winter Weather Advisory. The latest observations from both mesonet, ASOSs and AWOSs all show at or below freezing temperatures from near and north of I-96 from just east of Muskegon to Grand Rapids (at 32F) to south of Ionia (31F) . The precipitation is starting to develop over central Wisconsin into SE Minnesota as I am writing this. This area is expected to expand significantly in coverage over the next few hours and should reach southwest Michigan prior to midnight. This will all be rain overnight as it is warm enough aloft for rain. The latest runs of the HRRR and RAP model and the 18z NAMnest show temperatures near to below freezing most of the night over the northern parts of Muskegon, Kent and Ionia Counties. It just seems prudent to issue this Advisory before the precipitation begins. && .DISCUSSION...(This evening through next Monday) Issued at 320 PM EST Mon Feb 21 2022 - Freezing rain risk into Tuesday The latest runs of the models show the northeast parts of the CWA in a zone for freezing rain starting up tonight and continuing into part of Tuesday. Forecast soundings show temperatures slightly below freezing with a noticeable warm layer aloft. The main question is how long of a duration will it last and whether we will see more than a quarter in of ice. The latest High Res Euro shows the duration of the freezing rain to be limited with the model taking the above freezing temperatures through the northern zones by 13z Tue or so. The trend is for a sooner arrival of the above freezing temperatures and slightly higher values for the northern zones. Based on this we will keep amounts a quarter inch of less and the headline as an advisory. However...trends will need to be monitored closely for this event as just north of our CWA the below freezing temperatures persist. Any southward shift of this zone would warrant an ice storm warning headline. The southern edge of the freezing rain risk is somewhat uncertain as well...with the cities of Muskegon to Grand Rapids and Lansing very close to the possible impacts. Basically the thermal gradient will be tightening up on top of the CWA as the wave of low pressure moves in from the southwest. For Kent County the northeast sections of the county stand the greatest chance for seeing freezing rain and local impacts. Right now that is expected to occur in the middle of the night with surface temperatures rising to above 40 degrees by daybreak. Thus the window for freezing rain will be of a short duration if it happened at all for Kent County. Thus we will not expand the winter weather advisory further south. Again...close monitoring will be needed. - Thunderstorm risk late tonight into Tuesday. Elevated instability moves in during this window as a southerly low level jet of 30 to 40 knots advects Gulf moisture in. Mid level lapse rates approach 8.5 deg C/km around 07z to 10z for the southern parts of the CWA. Also a mid level shortwave will be moving in from the southwest Tuesday morning which will generate some lift. Thus we have expanded and increased the thunder risk in the forecast mainly for the southern half of the CWA. - Period of snow for Friday An 850 mb wave of low pressure is shown by the High Res Euro to track northeastward through southern parts of the CWA Thursday night into early Friday. Forecast soundings support snow with this system. The lift remains relatively weak which will act to keep the snow on the light side. ECMWF ensemble 24 hr snowfall amounts for this event show the members huddled around 1 to 2 inches for Grand Rapids and a little higher for Jackson. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 647 PM EST Mon Feb 21 2022 The low clouds are spreading in from the northeast to the southwest this evening as the cold air tries to penetrate farther south. I expect all TAF sites should be mvfr with cigs by 06z or so. I would expect IFR cigs/vsby at most if not all TAF sites between 09z and 21z Tuesday. There is the treat of freezing rain at both GRR, MKG and LAN early tonight (03z to 09z). It is a question of how quickly the precipitation starts verses how long it takes for the incoming warm front to push surface temperatures back up. At this point I believe the freezing rain will stay just north of I-96 TAF sites but we will keep a close eye on this. Overnight, it seems more of a drizzle sort of and event as there is not deep moisture. The deep moisture and instability arrive prior to sunrise on Tuesday. Locally heavy rainfall and a few thunderstorms are possible during that time frame. Expect low level wind shear overnight as there is 40 to 50 knots in the 2000 to 5000 ft AGL layer tonight. The bottom line is flight conditions will be best during the next 2-5 hours and after that will become challenging due to low ceilings, possible thunderstorms and in the 03z to 09z time frame the threat of freezing rain for the I-96 TAF sites. && .MARINE... Issued at 320 PM EST Mon Feb 21 2022 We will maintain the small craft advisory. Gusty east to northeast winds tonight will shift to the northwest by Tuesday night. The will remain up over 15 knots and that will lead to hazardous boating conditions for small craft. && .HYDROLOGY... Issued at 320 PM EST Mon Feb 21 2022 There are a couple of hazards to monitor for the rivers over the next couple of days. One is the ice jams and existing ice in the rivers. The crest on the Grand is approaching Grand Rapids this evening. There was still a decent amount of ice in the river around Comstock Park where minor flooding was ongoing. Any movement of this ice could result in sudden water level changes. Further downstream the ice had jammed up downstream of Robinson Township causing some water to back up behind it. This in combination with the approaching crest coming down the Grand has led to some flooded roadways. That will continue into Tuesday. Next up is the heavy rain risk for tonight into Tuesday. Some high res models like the HRRR were showing a swath of over an inch of rain through the heart of the CWA. Other models were more conservative with amounts closer to a half inch. Given the risk for convection and Gulf moisture advecting in...we do stand a chance to see those higher amounts. While that is not the most likely scenario with the warm front to feature some northward movement with time...if it stalls out...we could see a period of training convection and heavy rain. We will issue a hydrologic outlook for this potential event. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory until 7 AM EST Tuesday for MIZ050-057- 058. Winter Weather Advisory until noon EST Tuesday for MIZ043>046- 051-052. Winter Weather Advisory until midnight EST Tuesday night for MIZ037>040. Flood Watch through Tuesday afternoon for MIZ056. LM...Small Craft Advisory until 4 AM EST Tuesday for LMZ846>849. && $$ UPDATE...WDM DISCUSSION...MJS AVIATION...WDM HYDROLOGY...MJS MARINE...MJS
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1032 PM EST Mon Feb 21 2022 .SYNOPSIS... Warmth today will be replaced by cooler temperatures tomorrow with a threat of some wintry precipitation before a change to all-rain. Warmth returns with a vengeance on Wednesday as temperatures soar through the 50s into the lower 60s. More snowmelt and rain could lead to ice jamming issues over the interior as a result. High pressure builds in from Canada Thursday, then a snowy system crosses southern New England on Friday bringing a good chance of a plowable snow for much of the region. Cooler and quiet weather is expected this weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 1030PM Update: Temperatures remain highly variable as of 10pm with some spots falling into the mid 20s...with a few spots where winds have remained coupled sitting in the mid 30s. Have adjusted near term temperatures to match this trend...but no significant changes to overnight lows. Fairly substantial cloud cover for about the northern half of the forecast area. Clouds remain at or above 5kft...with any threat of drizzle/etc holding off until the morning hours Tuesday. 620PM Update: Going forecast looking good as of 6pm. Some spots have cooled pretty quickly given sunset and decoupling...and have lowered temperatures in these areas for the next few hours as a result. significant changes to the forecast at this time. Previous Discussion below... Overall a pleasant evening in store with clouds remaining over the higher terrain and spilling into the foothills. A lot of impressive temperatures today, but warmer values will be in store for Wednesday, discussed below. Clouds should remain fairly thin early on tonight, with temperatures dropping this evening. Do expect clouds to thicken towards morning amid WAA and moisture advection. However at the surface, light NNE winds will tap into cold air near the Quebec border, filtering into the higher terrain and mtn valleys. Model guidance has been quite strong with this infiltration, especially after a warm day Monday. Low temps in the teens can be expected in the northwestern tiers of counties in Maine, with lower to mid 20s along the foothills. Meanwhile, moisture will pool at the surface while dry air remains aloft. This will create the chance for some drizzle early Tues morning, some of which may contribute to slick surfaces before temps along the coast increase. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... Freezing rain expected inland Tuesday before changing to rain in the late afternoon and evening amid a strong warm surge. Drizzle and freezing drizzle will be possible region wide through Tuesday morning, with the freezing component mainly in the western terrain. While the low levels will be saturated amid a temp inversion, some remaining dry air at the surface may temper these drizzle chances until more steady precip arrives in the afternoon. HRRR and NAMnest temps overnight plunge freezing temps through southern Maine and NH come Tuesday morning. This is a much cooler trend, and will need to watch overnight temps and early morning temps. If cooler air does make it to the coast, slick roads may become more a threat here for the early/mid afternoon due to freezing drizzle or freezing rain onset. For the interior, the cold air will be much more difficult to scour out, resulting in the onset of more steady precip in the afternoon falling as freezing rain. Have issued a Winter Weather Adv in these locations, beginning with a potentially tight temp gradient from shore to foothills, and into the western terrain/NH. Precip will change to rain south to north through the evening hours, but have run the Adv until 11pm if northern areas lock in for longer. Greatest QPF is forecast to fall in the higher terrain and convergence over the foothills. Ice totals could approach two tenths of an inch, but expect most locations to measure lower than this. Power outages should be limited due to ice, however SE winds do increase as the transition to rain occurs. Some gusts to 30 cant be ruled out, but lower than 25 mph is most likely. With rain and rising temps moving in, ice cling should be short lived, particularly from the coastal plain into the foothills. See hydrology section for more on QPF and warm air impacts on area hydrology. Precip will taper early Wed morning, with just a few rain/snow showers occurring in upslope areas Wed afternoon/evening. The main talking point will be temperatures surging within a broad warm sector. Highs towards the lower 60s will be possible across southern NH and up portions of the ME coast. Temps will begin to crash during the evening as the main low finally clears into the Maritimes with NW winds flushing into the region. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Overview... Cool Canadian high pressure pushes into the region for Thursday, in the wake of the midweek system. Meanwhile a zonal jet overhead contributes to cyclogenesis over Appalachia with a trough digging down through the Mississippi valley... lifting toward the northeast late in week. These will bring us significantly cooler weather, a bit closer to normal anyway, with snow expected for Friday. The weekend looks similarly cool with quiet weather, except for a cold front crossing around Sunday or Monday. Starting Wednesday night... upslope snow showers and clouds will dwindle amid pressure rises from the west. Temperatures will be significantly cooler on Thursday, with t850 taking a 15-20 degree C tumble in around 24 hours over the region, so even with good mixing under mostly sunny skies afternoon highs are still progged to be mostly in the 20s and 30s. Cool northerly flow will set the stage for a snowy system set to arrive by Friday. For that snowy system... by Thursday evening, cloud cover will be on the increase as low pressure matures over the Tennessee and Ohio River Valleys. Driven by a shortwave trough lifting NEward over the eastern CONUS...ensemble and deterministic consensus brings the low near the southern New England coast, merging with a coastal low, and vastly simplifying the precipitation type forecast for our area. Medium-high confidence exists that all-snow will dominate over our forecast area with a cool ageostrophic feed from Canada... only reason it isn`t high at this juncture is because we`re a few days out yet and entire numerical suites have been known to shift, and the 0C isotherm for maximum Ts aloft does into Mass. The main question then turns to amounts. Classic ingredients will be in place given the maturity of the storm by the time it reaches New England with broad ascent associated with its frontogenetical circulation, shoved along by the parent trough`s stratospheric intrusion. The storm is expected to be progressive, but its track as it emerges into the Atlantic may allow good forcing to pivot near the NH/Mass border and prolong snowfall. The GEFS and ENS... along with their deterministic controls... have good potential for 1+ QPF over southern zones which, given climatologically average ratios, would give a foot or more of snow. There`s strong likelihood of a plowable snow over the southern third or so of the forecast area. Those amounts will taper toward the north, which is the main source of uncertainty... current indications bring just a couple inches near the international border. We`ll be on the northern side of forcing, which would likely lead to a drier and potentially fluffy/higher ratio snow. Snow like this can easily blow around and lead to poor visibility, that said wind fields aren`t expected to be particularly strong. For timing, have light snow breaking out Friday morning with heaviest accums during the midday and afternoon... exiting out over the waters through the evening. This scenario would significantly impact the Friday evening commute as well as travel to recreational areas for the weekend. Beyond this storm, quiet zonal flow takes over through much of the weekend with a more sunny mix of sun and clouds and a ridge of high pressure crossing. Saturday highs will likely land below average, in the teens to near 30... then increasing southwesterly flow behind the ridge axis leads to a slight warmup on Sunday with near-normal highs in the 20s and 30s. Models are in decent agreement bringing a cold front across sometime late Sunday / early Monday. What happens around this FROPA is still a bit up in the air; one interesting scenario has this phasing with a coastal low, amplifying near our coast, and bringing another round of snow as opposed to only a smattering of snow showers mostly over the mountains. An Arctic airmass comes in the wake of this cold front, but there is some disagreement for how far south this eventually reaches... nonetheless the trend to start the next work week will be a cool one. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... Short Term... Summary: A cold front sagging south into the region tonight will slowly push north as a warm front on Tuesday night bringing lowering clouds and the chance for drizzle/freezing drizzle on Tuesday followed by a period of rainfall Tuesday night. Restrictions: VFR conditions likely through the predawn hours before CIGS being lowering with MVFR CIGS likely by daybreak with further deterioration to LIFR/IFR CIGS/VSBYs by late Tuesday and Tuesday night. Freezing Precip: There is some potential for patchy freezing drizzle LEB-HIE-AUG Tuesday morning. By afternoon the potential for precipitation will increase while temperatures warm. Have not included mention of FZRA in this TAF set but by late afternoon there is that threat...esp at AUG. Will await better confidence in the guidance. Winds: Winds will become light northeast overnight...remaining less than 10kts. These light northeast winds will continue through the day on Tuesday before shifting out the south and increasing to 10- 20kts Tuesday night with gusts 25-30kts PSM-PWM-RKD-AUG Tuesday night. LLWS: No LLWS is expected through Tuesday. Tuesday evening...2kft southerly winds increase to 35-45kts which will likely necessitate LLWS in the TAFs beyond 00Z Wednesday. Long Term...VFR prevails with light NWerly flow on Thursday. CIGs will lower and SN breaks out across southern and western terminals Friday morning, spreading north and east and leading to significant restrictions through the day. IFR to LIFR is likely during this period along with northeasterly winds gusting to as high as 20-25 kts along the coast. Conditions improve to VFR as the system pulls away Friday night into Saturday. && .MARINE... Short Term...Some remaining waves around 5 ft possible this evening, but overall subsiding below SCA criteria. A quick wind increase from the SE Tues afternoon will result in Gale conditions overnight and early Wed morning. Another wind shift is expected Wed evening becoming W then NW as low pressure passing north of the waters and into the Canadian Maritimes. Long Term...Seas and winds will gradually diminish Wednesday night with high pressure building in for Thursday. Northeasterly winds will pick up Thursday night ahead of approaching low pressure, leading to another period of SCA conditions through Friday with widespread snow. Low pressure is expected to pass just south of the waters with winds taking a northerly clip late Friday. High pressure builds in for the weekend with winds gradually diminishing and turning westerly. && .HYDROLOGY... River levels remain elevated from melt/precip last week after a few cooler days to temporarily freeze new ice movement. The incoming precipitation Tues afternoon will add to hydro system stressors, particularly for a combination of warm snow temps, significant SWE, and prior jamming/releases. Have issued a Flood Watch where greatest confidence exists for ice jam issues; northern/central NH and far west ME. Expansion may be needed eastward with time and confidence. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Flood Watch from late Tuesday night through Thursday morning for MEZ007-012. Winter Weather Advisory from 1 PM Tuesday to 1 AM EST Wednesday for MEZ007>009-012>014-018>021-033. NH...Flood Watch from late Tuesday night through Thursday morning for NHZ001>007. Winter Weather Advisory from 1 PM Tuesday to 1 AM EST Wednesday for NHZ001>006-009. MARINE...Gale Watch from Tuesday evening through Wednesday morning for ANZ150>154. && $$ NEAR TERM UPDATE...Arnott
Area Forecast Discussion
National Weather Service Huntsville AL
857 PM CST Mon Feb 21 2022 .NEAR TERM...(Tonight) Issued at 857 PM CST Mon Feb 21 2022 Afternoon rain and thunderstorms have pushed northeast to locations mainly north of the Tennessee River early this evening. Scattered thunderstorms producing some heavier downpours have continued to develop this evening near and west of the I-65 corridor. Expect this activity to continue to move northward as low/mid level drier/warmer air moves into the region. Likely showers and a few thunderstorms were kept in the forecast through 10 PM. Further southwest, rain has mainly ended, but cannot rule out isolated to widely scattered showers or storms through midnight. This rainfall has helped keep us in the more stable airmass with some wedging working in from the east. Temperatures have dropped into the lower 50s in most locations. A few dewpoints have dropped into the upper 40s in northeastern Alabama. Despite winds, additional rainfall in northeastern Alabama through midnight will likely allow temperatures to drop to dewpoint values in those areas. Thus, have lowered low temperatures a tad into the upper 40s to lower 50s. These lows should happen between now and midnight. Then warm air advection and drier air in the lower/mid levels of the atmosphere from the south will continue advecting into the region overnight. This should allow temperatures to warm towards daybreak on Tuesday into the lower to upper 50s. Winds should remain between 5 and 10 mph with gusts at times to around 20 mph. These winds and continued cloud cover should keep fog from developing tonight. .SHORT TERM...(Tuesday through Wednesday) Issued at 218 PM CST Mon Feb 21 2022 Tomorrow will be a tricky forecast, with a decent chance for severe weather. Lets start with the overall pattern. As we go into Tuesday, we have a deepening low-pressure center located over central Missouri associated with shortwave activity in the southwesterly flow out ahead of the deep stationary upper-level trough over the western CONUS. As this low pressure circulation tracks northeast toward the Great Lakes and the Northeast, it brings a fairly dynamic cold front across the Tennessee Valley Tuesday night. Shear out ahead of this front will be substantial, with 0-3 km SRH values in excess of 400 m2/s2. Model soundings show a curved hodograph supportive of rotating updrafts which would organize storms into supercellular structures. The primary concern, again, will be whether we will have enough instability. This is the part that gets interesting/tricky. With cloud cover through the day tomorrow, you`d think we won`t be able to destabilize very well, and a lot of the time that is true. However, with temperatures warming via southerly winds advecting in more warm, moist air, we`ll be not only starting the day around 60 degrees in the morning, but we will likely warm above 70 degrees by the afternoon. The national blend of models shows that 75% of the model solutions have the temperature at Huntsville getting above 72 degrees tomorrow afternoon. Looking at model soundings from both the global models, the NAM, and the HRRR. They don`t show much instability, but they also have surface temperatures down around 66-68 degrees. If you warm the surface temperature up to around 73-75 degrees, that erodes away much of the cap leaving more instability to work with. Looking at the HRRR which, since 00Z last night at least, has been showing supercellular structures in the model reflectivity, this would certainly support a chance for strong to severe thunderstorms, especially west of I-65 where temperatures in NW Alabama could get up near 75. These occur out ahead of the cold front and will need to be watched. Models have them developing around 2-3 PM. As the afternoon progresses into the evening hours, these cells merge into more of a linear feature and hang up along the storm-relative flow which will be perpendicular to the line. This will allow for convection along the front to catch up to this feature leading to two lines of fairly heavy rainfall merging right across our entire area. This is where we have our significant potential for flooding/flash flooding overnight tomorrow night. The front slows down as it hangs up on the storm-relative flow as well, becoming nearly stationary across our area, training heavy rainfall across the same areas for hours. This will bring a widespread swath of 1-2.5 inches of rain, with most of it falling between midnight and 6 AM Wednesday. Wouldn`t be surprised if there were areas that saw more. As we go into Wednesday morning, we get a break in the rain as the front finally drops to our south for about 6-12 hours. .LONG TERM...(Wednesday night through Sunday) Issued at 218 PM CST Mon Feb 21 2022 An upper low pressure system over the Pacific NW and west of the northern Rockies will move southward, continuing a general troughing pattern over the greater CONUS. This troughing should be extending S-SW from upper lows over NE Canada and the Davis Strait, being somewhat held up by strong upper ridging over the eastern Gulf region. Another strong upper disturbance now south of SE Siberia will move in the northern stream and help push the trough east of the region during the weekend. The deterministic models were in rather good agreement with big picture system positions early next week, all showing troughing moving off of the eastern seaboard. At the surface, a storm system now over the eastern Great Plains, by late Tuesday should be heading rapidly to the NE over the Great Lakes. A frontal boundary extending south of this low will gradually approach the Tennessee Valley. Strong and cold Canadian high pressure moving to the SE from Alberta will help push the frontal boundary across the Tennessee Valley on Wednesday. An aformentioned upper disturbance in the polar jet will help develop another over the Desert SW on Thursday. This system as it heads eastbound will bring overrunning type showers and a few thunderstorms over the Valley during the Thu to early Friday timeframe. Kept most of the thunder over our western areas closer to that system. Some of the rain with this system will be locally heavy late Wed to early Fri. Excessive rainfall of another one to over three inches on top of an already saturated ground will runoff and contribute to more areal flooding issues. The heaviest rainfall with this system appears will remain to our north and west, but will be very close. The Flood Watch we have going now may need extending if this heavy rainfall looks more likely. Overall storm strength overall should be on a weaker side with the higher instability staying to our south and east. The cold front should push across the area on Fri bringing an end to the heavy rainfall. Much colder air filtering in behind the front will bring a noticeable drop in temperatures to close out the work week. After highs on Thu warming into the upper 60s and lower 70s, despite clouds and showers, they will struggle into the upper 40s to lower 50s on Fri and during the weekend. With cold air in place, another upper system is forecast to move across the area late Saturday into Sunday. With highs only near 50 on Sun and falling below freezing that night, a mix of rain/snow looks possible as we go into a new workweek. It`s way too far out to contemplate accumulation. Think most ground surfaces should remain free of snow accumulations, but cannot say the same for elevated surfaces or grassy areas. Another shot of even colder air will end the month of February on a chilly note with highs only in the mid 40s and lows to start the month of March in the lower 20s. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 527 PM CST Mon Feb 21 2022 MVFR to IFR CIGS/VSBYS and maybe some CB are expected at times through 1Z, before a round of stronger TSRA are expected between 2Z and 4Z at KMSL and between 3Z and 5Z at KHSV (IFR to MVFR CIGS/VSBYS possible then), as a warm front moves through the terminals. Expect easterly winds to become southerly after midnight remaining around 10 knots with gusts around 20 knots. Expect conditions to become predominantly VFR after 6Z. Wind gusts should pick up a bit more after 15Z on Tuesday with gusts up to 28 knots possible. Wind shear around 40 knots is expected through 15Z. Another round of TSRA is expected to affect the terminals after 21Z. For now only included PROB30 group including TSRA and IFR CIGS being so far out in the forecast after 21Z. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...Flood Watch from Tuesday afternoon through Wednesday morning for ALZ001>010-016. TN...Flood Watch from Tuesday afternoon through Wednesday morning for TNZ076-096-097. && $$ NEAR TERM...KTW SHORT TERM...McCoy LONG TERM...RSB AVIATION...KTW For more information please visit our website at
Area Forecast Discussion
National Weather Service New Orleans LA
932 PM CST Mon Feb 21 2022 ...EVENING UPDATE... Performed a small update to the near/short-term forecast to reflect recent model guidance and obs trends. We are continuing to see low clouds build in for just about all of the area, with cloud bases ranging between 1000 to 2500ft AGL. Low clouds will likely persist through the night and into daybreak Tuesday with an overall moist PBL to low-level thermal profile in place. Right above, we are starting to see the front edge of dry air advecting in between 900 and 800mb from the western Gulf, with vertically deeper, drier air expected to continue to build into the region through early Tuesday, leading to increased subsidence/compressional warming resulting in a strengthening low to mid-level inversion. Meanwhile, a subtle mid-level impulse, riding SW 500mb flow has already led to convection igniting across the south-central Plains, with a weak surface low/trough developing and expected to quickly eject northeast through early Tuesday. With greater upper-level dynamics racing away from the region (subtle height rises aloft), we never really see enough large-scale dynamic ascent to offset the warm thermal layer situated in the low to mid-levels regardless of building temperatures/instability throughout the day. Something additional to note: H5 to H7 lapse rates are relatively high, but this is because of compressional warming in the upper portion of the inversion per recent forecast soundings. 00Z HRRR guidance barely has any convection in the CWA, and whatever forms across SW MS struggles to attain enough vertical depth due to all the aforementioned unfavorable conditions working against deep convection. However, looking closer at the SFC to 925mb wind profile over the area hints at just enough low-level directional wind convergence from east to west across the area, allowing for perhaps enough localized lift to lead to a few isolated bands or "streets" of shallow showers maybe some storms, primarily north of I-10/12 at times during the day. But overall, not anticipating severe weather in our CWA with any mentionable threat primarily to our north. But as always, will monitor especially across far northern areas. Did slightly adjust highs for Tuesday to account for the warmer bias we saw today underneath strong return flow. Aiming closer to the 75th percentile in the ensemble spread placing many areas in the 80s to perhaps some mid 80`s in a few places with no other adjustments required elsewhere. KLG && AVIATION (00Z TAF DISCUSSION)... Primarily VFR to a few mixed MVFR CIGS persist this evening with low to mid-level clouds in place. Forecast calls for low clouds to build in yet again later this evening into tonight, with a majority prevailing MVFR to periodic IFR expected into daybreak tomorrow. Can`t rule out a patchy isolated area of light showers or drizzle primarily after 03Z thru 14Z in a rich, moist return flow airmass in place. Otherwise, surface winds will remain relatively elevated all night at around 07-14kt sustained bearing 150 to 170 into the day on Tuesday, with patchy clouds and VFR/MVFR CIGs expected thru Tuesday afternoon/evening. KLG PREV DISCUSSION... /issued 345 PM CST Mon Feb 21 2022/ SHORT TERM (TONIGHT THROUGH THURSDAY)...The forecast area will remain embedded beneath a persistent southwesterly flow pattern in the mid to upper levels through Thursday night. Embedded within this southwest flow, two fast moving shortwave troughs will pass through the Plains and into the Midwest. Only the trailing end of these troughs is expected to pass directly over the area, but upper level forcing should sufficient to bring an increased chance of rain to the area during the day tomorrow. Fortunately, the risk of severe thunderstorms has diminished due to the further north track of the upper level system. Shear values are not anticipated to be as high as previously thought, and this should help to keep any thunderstorms that form tomorrow below severe limits. At most, a very isolated strong to severe thunderstorm could form over parts of Southwest Mississippi where shear values will be greatest tomorrow afternoon. The deep layer southerly flow pattern will continue to usher very warm into the area, and highs should climb into the upper 70s and lower 80s during the afternoon hours. This warm and humid airmass will be passing over cooler nearshore waters, and a weakening of the wind field tomorrow night to around 10 knots will be very supportive of a decent sea fog event forming by the evening hours. This dense sea fog should spread inland through the night, and the forecast calls for fog across most of the forecast area by daybreak on Wednesday. This fog may then linger over the coastal waters through the entire day on Wednesday, but should clear over land areas by the afternoon. Skies should turn partly cloudy by the afternoon hours as some drier air in the mid-levels associated with a weak shortwave ridge axis and increased upper level subsidence mixes down to the surface. This slight increase in solar insolation and the weak subsidence aloft should also allow temperatures to climb into the lower to middle 80s or near record high levels by Wednesday afternoon. There may be a few widely scattered showers and possibly an isolated weak thunderstorm that forms over the northern third of the CWA Wednesday afternoon, but slightly weaker mid-level lapse rates will limit overall convective potential through the day. Another round of dense advection fog will impact the area Wednesday night into Thursday morning. This fog will linger through the late morning hours, but should begin to lift as the second shortwave trough axis begins to approach the region from the west. As mentioned earlier, the main core of this upper level trough will pass well north of the region, but this will also be a much deeper system. As a result of this deepening, a low pressure system and related cold front will form over the Plains Wednesday into Thursday. As the parent trough begins to pull into the Midwest, the surface low and front will also quickly track to the east. This front is expected to pass through the forecast area Thursday night into Friday morning, and a band of rain should accompany it`s passage. Mid-level lapse rates will remain weak, so the risk of thunderstorm activity will be low to non-existent as this front moves through. In fact, the majority of the rain will develop in the wake of the front on Thursday night, as cooler air near the surface is overrun by the continued warmer and more humid southwesterly flow regime in the mid to upper levels. Temperatures will remain very warm, and some compressional heating in advance of the front could push temperatures into the mid 80s and into record high territory at several locations Thursday afternoon. Temperatures should begin to cool quickly after frontal passage, and readings are expected to be in the 40s and 50s by daybreak on Friday. LONG TERM (FRIDAY THROUGH MONDAY)...Model spread has lessened, and forecast confidence has increased for the upcoming main Mardi Gras weekend. The southwesterly flow pattern in the mid and upper levels will continue through Saturday, and this will keep skies overcast for both Friday and Saturday as the warmer and humid air is isentropically forced over a shallow cold pool near the surface. Fortunately, strong subsidence and negative vorticity advection above an elevated temperature inversion associated with a 925mb thermal trough axis sliding through the region will reduce rain chances to near zero from Friday evening through Saturday evening. This drying out is most evident in the low precipitable water values of around half an inch currently forecast by medium range guidance. The thermal trough axis and the overcast skies will make for a very chilly couple of days. Highs should only warm into the upper 50s and lower to middle 60s each day and overnight lows should dip into the 40s. The timing of the next shortwave trough axis has come into better agreement, and most ensemble members are pointing to a passage of this trough and cold front on Sunday. Little in the way of low level moisture return is expected as winds remain largely offshore in advance of this system, but enough mid-level moisture should feed into the region to allow for at least chance PoP during the day on Sunday. A lack of instability will keep the risk of thunderstorms suppressed, but another post-frontal rain band could pass through the region on Sunday. The rain should be very short- lived as the flow pattern aloft turns northwesterly in response to the southern stream trough phasing with a northern stream system moving into the Great Lakes by Sunday night. This deep layer northwest flow pattern will lead to rapidly clearing skies Sunday night into Monday and much colder air advecting into the region. Overnight lows should fall into the 30s and lower 40s Sunday night and similar conditions are expected for Monday night. Highs on Monday will struggle to reach the upper 50s as a very cold airmass moves in from the north. MARINE...The pressure gradient has tightened considerably today in advance of an approaching low pressure system, and this has resulted in southerly winds of 15 to 20 knots taking hold over most of the coastal waters. These winds should persist into tomorrow before easing tomorrow night as the gradient over water relaxes slightly. However, this easing of the wind field will make the formation of dense fog more likely. This dense sea fog will likely form during the evening hours tomorrow and then potentially persist through Thursday morning before lifting. It will take the passage of a strong cold front Thursday afternoon into Thursday night to fully clear the fog, but a return to small craft advisory conditions is expected after the front moves through. These stronger winds of 20 to 25 knots and seas of 4 to 7 feet will develop by Friday morning and continue through Saturday. && .PRELIMINARY POINT TEMPS/POPS... MCB 65 85 65 81 / 10 50 20 40 BTR 66 84 66 82 / 10 40 10 30 ASD 63 83 63 78 / 10 30 10 20 MSY 66 83 66 78 / 10 30 10 10 GPT 62 76 62 73 / 10 20 10 10 PQL 61 79 62 76 / 10 20 10 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...Small Craft Advisory from 3 AM to noon CST Tuesday for GMZ550- 552-570-572. MS...None. GM...Small Craft Advisory from 3 AM to noon CST Tuesday for GMZ552- 570-572. && $$
Area Forecast Discussion
National Weather Service Marquette MI
946 PM EST Mon Feb 21 2022 .UPDATE... Issued at 946 PM EST MON FEB 21 2022 Long-duration winter storm continues this evening for areas along and north of M-28 west of Marquette associated with a band of fgen at 700 mb. In addition, NE wind upslope off Lake Superior is keeping lake effect snow bands/showers going into the northern half of Marquette County on the southern edge of the synoptically-forced snow. The concern is tomorrow afternoon with the well-advertised second wave of this storm. 21z RAP and 00z HRRR show impressive 6-hour QPF amounts of 0.35-0.5" in the 18z-00z time frame generally along and northwest of a line from Iron Mountain to Munising. Further complicating things is the banded precip signal in QPF fields from both of these models which may lead to snow amounts varying considerably over short distances. The other complicating factor is the thermals. Although this has been advertised as a light and fluffy snow, in reality the warm nose moving in as the 850 mb low tracks from Menominee to Manistique will lead to warming outside of the DGZ and thus lower SLRs, as well as perhaps some sleet south- central and east. Will note that the 00z NAM is right on the money with the 850 mb temp at MPX vs the 00z sounding, whereas the 00z RAP is about 2 C too cold. There will be a period of heavier snow rates with lower SLRs leading up to and during the evening rush hour tomorrow. These additional amounts, plus what`s already fallen, could justify an upgrade to a Winter Storm Warning for the western half of the CWA. However, have decided to hold off since it would be confusing to upgrade now only to have people wake up and see little to nothing happening in the morning. However, an upgrade may be needed with the morning package if the CAMs do not stray from their current solutions. That said, did incorporate some of the aforementioned wetter guidance to boost snow amounts tomorrow afternoon by about 1-2" over the previous forecast over the western half of the CWA. && .SHORT TERM...(This evening through Tuesday) Issued at 156 PM EST MON FEB 21 2022 System snow is starting to move in this morning and on the radar, can see lake effect snow moving southwest near Marquette County as well and system snow moving east. Sharp cutoff to the pcpn exists from Iron Mountain to just north of Escanaba and Manistique and look for that to continue this afternoon. Can definitely see the Lake Superior influence in banding in the snow in Marquette County. Overall, the forecast still looks good and no updates planned. .LONG TERM...(Tuesday night through Monday) Issued at 344 PM EST MON FEB 21 2022 Overall thinking of the evolutions of the weather systems during the first 36 hours of the forecast beginning tonight has not changed a lot...just some subtle changes. Frontogenesis axis has been setup mainly along and north of the M28 corridor from Ironwood to Marquette. Most areas in this zone will have seen 2-5 inches of snow by early this evening with the highest totals in northeast winds upslope areas with several narrow bands of lake effect streaming in from the northeast. FGEN forcing wanes overnight with main snow forcing transitioning to mainly light lake enhanced/upsloping. Snow amounts from midnight tonight through mid-morning Tuesday will be in the 1-3 inch range. Have lowered snow total a little for the overnight and Tuesday morning time period mainly due to lower SLR`s. Our SLR`s thus far have been running around 12:1...a little lower than would have thought. With warm nose increasing around 80H overnight into Tuesday...will lose deeper DGZ and thus do not think SLR`s will get any higher than current. Main surface wave moves from northern IL into lower Michigan tomorrow. Deformation precip area will move across the U.P. during the afternoon and early evening with the next round of moderate precipitation. Northeast wind upslope and enhancement will continue so highest snow total will continue to be in the highlands of Marquette/Baraga counties and near the Porkies. Biggest question and challenge of the whole snow forecast is along the US2 corridor from Delta county into the eastern U.P. There could be a little sleet that mixes in this area with 80H warm nose surpassing freezing. Snow amounts have been lowered in this area to more in the 3-5 inch range...mainly Tuesday afternoon/evening. However, this remains the zone of least confidence and amounts could trend back slightly higher. No changes are planned to ongoing headlines. With only minor amounts of snow expected across the south and east through midday Tuesday won`t add any additional advisories at this time. Will keep the advisory across the west mentioning the overnight lull in snow before increasing again tomorrow afternoon. Weather becomes much quieter after any lingering lake effect dies down on Wednesday. A system may move through the lower lakes Friday grazing southern areas and another clipper over the weekend could increase lake effect briefly on Sunday...but no major storms are expected any time soon beyond this one. Other than Saturday when temperatures will be close to normal, temperatures will remain below normal into early next week. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 633 PM EST MON FEB 21 2022 LIFR vis continues at IWD and CMX for the next few hours before the first wave of snow pulls out to the northeast late this evening. SAW remains on the southern edge of this wave of snow, but is also dealing with NE wind upslope/lake effect snow showers embedded within the wave of snow. Late tonight, all terminals should go IFR with much lighter snow between waves. CMX and IWD may even see a brief period of MVFR vis early tomorrow morning. All terminals will then drop back into LIFR by late morning or early afternoon Tuesday as the second wave of snow moves in from the southwest. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 344 PM EST MON FEB 21 2022 Northeast gales to 40 knots will continue through Tuesday night before diminishing. Heavy freezing spray will continue through Wednesday. Winds will be light Thursday and Friday...mainly below 20 kts. Next clipper moves in over the weekend with the potential for southwesterly gales ahead of it followed by gusty northwest winds late in the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 7 AM EST /6 AM CST/ Wednesday for MIZ001>005-009-010-084. Lake Superior... Heavy Freezing Spray Warning until 7 PM EST Wednesday for LSZ243- 244-263-264-266-267. Gale Warning from 1 PM Tuesday to 7 AM EST Wednesday for LSZ249>251-266-267. Heavy Freezing Spray Warning until 7 AM EST /6 AM CST/ Wednesday for LSZ162. Gale Warning until 7 PM EST /6 PM CST/ Tuesday for LSZ162. Gale Warning from 7 AM Tuesday to 7 AM EST Wednesday for LSZ243- 244-264. Gale Warning until 7 AM EST /6 AM CST/ Wednesday for LSZ240>242- 263. Lake Michigan... None. && $$ UPDATE...RJC SHORT TERM...07 LONG TERM...MZ AVIATION...RJC MARINE...MZ
National Weather Service Morristown TN
933 PM EST Mon Feb 21 2022 .UPDATE... EVENING UPDATE. && .DISCUSSION... Radar shows showers moving in from the southwest. No lightning yet over our area, but there are a few flashes off to our west and southwest and a few rumbles cannot be ruled out overnight especially south/west although convective energy will be very limited. Current forecast generally looks to have a decent handle on the precipitation. Biggest change with this update will be to lower min temps across nearly all of the area as current temperatures are approaching the forecast lows in many locations. The cloud cover and wind will not allow temps to drop too much more, but will make some adjustments. Will also tweak sky cover and dew points with this update. Will leave the Tuesday high wind warning in the mountains as is for now, and no changes to the flood watch for Tuesday night. && .AVIATION... 00Z TAF DISCUSSION. Will see an area of showers move across the area from southwest to northeast tonight. CHA will be MVFR for much of the period before some improvement to VFR late, and may dip to IFR in a heavier shower early. TYS/TRI look likely to stay mainly VFR, but will try to time better chance for showers with tempo groups including MVFR vsby and cigs later tonight. Other concern will be possible LLWS. The strongest probability for LLWS looks to be at CHA so will include for several hours there later tonight/early Tuesday. LLWS looks borderline at TYS/TRI later tonight so will leave out for now. Winds will be gusty from the southwest Tue afternoon. && .PREV DISCUSSION... /ISSUED 255 PM EST Mon Feb 21 2022/ SHORT TERM...(Today through Tomorrow) Key Messages: 1. Initial round of showers moves into the forecast area tonight, marking the beginning of a wet week ahead. 2. High Wind Warning issued for the southern Appalachian Mountains tomorrow. Discussion: Initial round of rain showers with a few embedded weak thunderstorms is moving across the Tennessee Valley this afternoon. It`s continuing to weaken as it moves further east away from the better isentropic lift, but it is remaining somewhat stronger and more organized than most CAMs and guidance suggested. Have bumped up PoP chances and QPF amounts a bit along the southern TN border to account for these radar trends. Surface obs and radar estimated precipitation totals generally paint most locations as seeing around 0.10" or less per hour associated with this round of rain. Expect the majority of it to remain south of the TN border as it moves eastward, but southeast TN into southwest NC will likely pick up measurable precipitation with it. Isolated weak showers will likely remain in the area this evening into the overnight hours as the front makes it`s way closer to the area. Minimal precipitation is expected from these weak showers however. But the increased cloud coverage, and more southerly wind will keep overnight temperatures pretty warm, with most locations in the Valley expected to remain in the upper 40`s or low 50`s for a minimum temperature. Tomorrow during the daytime expect the precipitation to mostly be out of our area, sticking to the north and west closer to the better synoptic forcing. Likely the most notable weather during the daytime hours tomorrow will be the breezy southerly to southwesterly winds as the low level jet moves into the region. This 50+ knot jet will cause the biggest impacts in the southern Appalachian Mountains during the daytime tomorrow. There looks to be enough of a southerly component to the winds that we`ll experience some weaker mountain wave effects with this jet. But with a 50+ knot jet regardless of the direction it`s going to be very breezy in the higher elevations along the Appalachians. Will upgrade the High Wind Watch to a High Wind Warning for tomorrow. Elsewhere most people will notice the very warm temperatures and breezy conditions associated with this jet as most people in the Valley should see temperatures climb above 70 tomorrow. ABM LONG TERM...(Tuesday night through Monday)... Key Messages: 1. Excessive rainfall will be the main concern on Tuesday night and again on Thursday/Friday. 2. Strong winds expected expected across the higher elevations Tuesday night and again on Thursday night. 3. Cooler airmass and a southern track system could bring some mixed precip to the Southern Appalachians on Sunday but uncertainty is high. Discussion: A cold front will begin to stall as it moves southeastward across the Tennessee Valley on Tuesday evening into the overnight hours. Convection will be occurring along and ahead of this front. A jet streak across the Ohio Valley will place us within the right entrance region for upper divergence as well as diffluent flow aloft. RAP model guidance suggests PW values around 1.6 inches which is near the max of climatology. In addition, MLCAPE of 100 to 200 J/Kg and MUCAPE of 300 to 500 J/Kg will limit severe convective potential. This skinny CAPE profile and high moisture will be supportive of convective updrafts supportive of heavy rainfall, and this is further supported by saturated forecast soundings and deep warm cloud layers. With storm layer flow parallel to the front, some training convection will be possible. With potential training and a favorable setup for heavy rainfall rates, conditions will be favorable for locally heavy rainfall. For this reason, will issue a Flood Watch to match up with neighbors that is focused on locations for potential heaviest rainfall rates. Overall QPF totals are expected to be one to two inches, but locally higher amounts of three to four inches will be possible with any training cells. The front is forecast to be south of the forecast area on Wednesday with dry conditions across our zones. Southerly flow will bring this front northward Wednesday night and Thursday with increasing clouds and precip across the region once again. As the cold front moves across the area on Thursday night, additional rounds of locally heavy rainfall will be possible as PW values near 1.6 inch will be around the max of climatology. Forecast soundings show the saturated airmass and a relatively deep warm cloud layer depth for this time of year. Most of this week is forecast to be above normal for temperatures with the warm southerly flow and ridging across the Southeast CONUS. Northerly flow will bring drier air late Friday through Saturday as high pressure builds in from the northwest as temperature dip back below normal. A shortwave moving eastward across the Southern Great Plains is forecast to initiate cyclogenesis across the northern Gulf Coast on Saturday night or Sunday with the potential for mixed precip spreading northward across the Southern Appalachians. Any frozen precip would be most probable across the higher elevations. With this being a Day 6 system, confidence is low in any direct impacts or precip amounts. JB && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 51 72 60 70 55 / 60 40 90 60 50 Knoxville McGhee Tyson Airport, TN 50 73 58 66 51 / 60 40 90 60 60 Oak Ridge, TN 50 72 57 67 49 / 70 50 100 50 70 Tri Cities Airport, TN 46 71 56 65 49 / 60 40 90 60 70 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...Flood Watch from Tuesday evening through Wednesday morning for Anderson-Bledsoe-Blount Smoky Mountains-Bradley-Campbell- East Polk-Hamilton-Knox-Loudon-Marion-McMinn-Meigs-Morgan- Northwest Blount-Northwest Monroe-Rhea-Roane-Scott TN- Sequatchie-Southeast Monroe-West Polk. High Wind Warning from 7 AM to 7 PM EST Tuesday for Blount Smoky Mountains-Cocke Smoky Mountains-Sevier Smoky Mountains. VA...NONE. && $$
Area Forecast Discussion
National Weather Service Pendleton OR
745 PM PST Mon Feb 21 2022 .UPDATE...An upper level low pressure system slowly moving through the region was continuing to produce light snow across the area. The latest web cams was showing heavy snow over portions of the blue mountains and thus the wsw had been extended into the night for this area. Meanwhile the nbm continued to show accumulating snow over central Oregon eastward although this decreases somewhat towards seneca. Otherwise another band of light snow is continuing to strike the southern blue mtns and all the winter weather advisories have also been extended into the night. Colder air on nne winds may also create some upslope that may also add to some of the accumulation and persistence. The probabilistic graphic generator was indicating tonights low temps dropping into the single digits across portions of central Oregon and the area mountains and between 10 to 15 in the basin. Even colder temps are expected Wednesday morning. Otherwise changes had been done to amts...winds...and now the short term forecast appears even more on track. && .PREV DISCUSSION... /issued 255 PM PST Mon Feb 21 2022/ SHORT TERM...Tonight through Wednesday Night...A large and deep upper trough continues to move south over the forecast area this afternoon. Clouds show some convective nature and snow, rain and even some some graupel showers have been happening this afternoon and will continue this evening before tapering off late tonight and tomorrow morning. The showers have been a little slower to develop and the HRRR continues them longer than earlier runs, so will be extending current Winter Weather Advisories and Warnings through 7 PM this evening. An exception will be the Winter Weather Advisory along the East Slopes of the Oregon Cascades which will continue through 10 PM this evening. The Southern Blue Mountains, Ochoco- John Day Highlands, the East Slopes of the Oregon Cascades will get another 2 to 5 inches of snow with 1 to 3 inches in the Northern Blue Mountains and Central Oregon. An Arctic Cold Front is now moving into the area and winds are turning northerly and increasing to 10 to 20 mph already in the Yakima and Kittitas Valley and in the Lower Columbia Basin north of the Tri-Cities. Expect that the breezy to windy conditions will continue from now until tomorrow evening over most of the area. At the same time, as anticipated, temperatures are already falling and a very cold period will be with us for the next few days. Temperatures approaching record lows will be possible tonight but even more so Tuesday night as temperatures get even colder. Temperatures tonight will be in the teens in the Columbia Basin and 2 to 12 above in the mountains and central Oregon. Tomorrow night the Columbia Basin will be 5 to 15 above with 5 below to 5 above zero elsewhere. Daytime temperatures Tuesday and Wednesday will be in the 20s and lower 30s with 10 to 20 in the mountains. One additional concern will be the cold temperatures and windy conditions developing very cold wind chills. Tonight through Wednesday will see wind chills below zero in many locations with values at times reaching 10 to 15 below zero. At this time, it does not appear that wind chills will reach the criteria for a Wind Chill Warning but this will have to be monitored over the next couple of days. By Wednesday night, the trough will shift a little eastward and an offshore ridge will begin to influence our area. This will begin to moderate the temperatures with the lower elevations warming a few degrees to the mid teens to lower 20s while the mountains and central Oregon will warm to zero to 10 above. Winds will be lighter Wednesday and Wednesday night and no precipitation is expected Tuesday night through Wednesday night. Perry/83 LONG TERM...Thursday through Monday...The long term is characterized by a warming trend that is expected beginning on Thursday that will bring our region to near seasonal temperatures through the end of the week and into the weekend, with a weak system on Thursday possibly bringing light mountain snowfall, with a more impactful system late in the weekend. Models are having trouble to start the forecast period with a weak trough diving across the borders of WA/OR/ID. This continental based upper level system is expected to be fairly dry, but the ECMWF and its ensembles shows a notable band of precipitation out of this feature, while the GFS/GEFS remains drier with perhaps a very quick shot of light mountain snowfall for the eastern mountains of our region. Ensemble analysis isn`t easy, but based on 500mb height anomalies and the cluster phase space diagram, there is better agreement with the ECMWF and its ensembles vs the GFS. Therefore, although the NBM remained quite dry for this run, elected to at least produce a signal of precipitation for the Blues and Wallowas, but it does remain very light, and confidence in this precipitation is low (20-30%). After this feature departs into Friday, high pressure ridging takes hold and remains the dominant weather feature through Saturday evening. Temperatures continue to rebound all weekend, with highs in the upper 40`s by Sunday and 50`s by Monday for the lower elevations. A deeper, marine based upper level trough is expected to begin overspreading the region late Saturday into Sunday, with a wetter pattern expected to end the weekend and begin next week. Precipitation amounts look light, with continued warming raising snow levels through the end of the forecast period. Goatley/87 AVIATION...00Z TAFs...Mostly VFR to MVFR conditions continue. Periods of IFR remain possible as ceilings drop locally and visibilities reduce due to nearby snow. Precipitation expected most sites through 06Z, with lingering snowfall through 09Z for BDN/RDM. Breezy northerlies expected overnight, continuing into Tuesday and overspreading most sites except DLS. Strongest winds YKM/PSC with gusts 20-30kts. Goatley/87 && .PRELIMINARY POINT TEMPS/POPS... PDT 14 27 8 26 / 40 0 0 0 ALW 18 30 10 28 / 30 0 0 0 PSC 19 33 15 32 / 20 0 0 0 YKM 14 29 8 31 / 20 0 0 0 HRI 17 31 12 30 / 20 0 0 0 ELN 12 25 7 27 / 10 0 0 0 RDM 8 24 -3 27 / 60 10 0 0 LGD 12 22 4 21 / 40 10 0 0 GCD 13 26 2 26 / 50 10 0 0 DLS 21 32 15 33 / 40 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory until 4 AM PST Tuesday for ORZ503-506- 509. Winter Storm Warning until 4 AM PST Tuesday for ORZ502. WA...Winter Storm Warning until 4 AM PST Tuesday for WAZ030. && $$ SHORT TERM...97 LONG TERM....87 AVIATION...87
Area Forecast Discussion
National Weather Service Topeka KS
834 PM CST Mon Feb 21 2022 .UPDATE... Issued at 834 PM CST Mon Feb 21 2022 The cold front has been much faster moving into the forecast area this evening and the 00Z models are still trying to catch up with the magnitude of the cold air advection. Have noticed a lot of surface obs across south central NEB have been reporting light snow. And GID pointed out the RAOB from LBF showing the cold air much deeper with the stratus cloud in the dendritic growth zone a few thousand feet off the ground. Even the OAX RAOB has the base of the stratus layer near -10C. This may diminish the chances for freezing drizzle overnight if the stratus layer is colder then the models prog allowing for more flurries than drizzle. Have trended the forecast in this direction but am hesitant to pull freezing drizzle completely out of the forecast. The faster progression of the cold front does seem to limit the chances for thunder this evening across east central KS. 01Z RAP forecast soundings suggests what ever instability there will be is over east central KS now. With the cold air moving through faster and convection still down along the Red River, have removed the chance for showers and thunderstorms across east central KS. Saturation and lift in the low levels appears to be more limited across this area as well, so I don`t bring the snow or freezing drizzle this far south. Have also bumped up wind speeds across the entire area with models showing a good pressure gradient through the night. Even with the stronger winds and quicker drop in temps, wind chill values look to remain above -15F over north central KS. So I don`t plan to add any counties to the wind chill advisory at this time. && .DISCUSSION... Issued at 248 PM CST Mon Feb 21 2022 At 20Z today, a strong cold front bisected the CWA creating a large temperature gradient from northwest to southeast across the area. Temperatures were falling quickly behind the front. At KCNK (Concordia) temperatures dropped 10 degrees between 19Z to 20Z and were in the low 40s at 20Z. Meanwhile at KMHK (Manhattan), temperatures were at 70 degrees at 20Z. Ahead of the front this afternoon, elevated fire danger conditions will remain in place given low RH values and breezy winds. A few storms could develop along the boundary by about 02Z (8 PM) near or just north of I-35 where about 200-400 J/kg of CAPE could build. As the colder air mass overspreads the area, soundings show a saturated layer a few thousand feet deep in the low levels (under 5,000 ft AGL). As lift increases through the layer, drizzle could develop with a possible limiting factor being a layer of drier air in the lowest 1,000 feet. If drizzle can overcome the drier air for a few hours, a few slick spots could develop by early morning since temperatures will be below freezing in most spots. The best chance for the drizzle will be across northern and eastern portions of the CWA. In stark contrast to temperatures today, highs tomorrow will only range from around 20 degrees in northern KS to near 30 degrees in east-central KS (a good 40 to 50 degree difference in 24 hours). Cold weather will be here to stay for the rest of the week. Wind chills by Wednesday morning are forecast to drop to between -10 and -15 degrees, which could warrant an advisory for counties in far northern KS. Another mid level system will move over the area on Thursday. Some good lift should be realized early as the area becomes positioned under the left exit region of a 100 knot jet. Models, however, are showing dry air at 500 mb. Thus, light precipitation is expected at this time, most of which should fall as snow. At this point, we are forecasting minor accumulations of less than a inch before the better dynamics move east of the area. Cold air becomes reinforces as a surface ridge builds in late this week and early next weekend. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 458 PM CST Mon Feb 21 2022 The cold front is moving through a little sooner than expected. Think this probably keeps the TS chances southeast of FOE. There is good agreement in MVFR stratus moving in behind the front. Forecast soundings continue to show some vertical motion within the cloud. However RAP isentropic surfaces are not as obvious with the lift implying any -FZDZ could be pretty temporary. Of all the guidance, the NAM is the only one generating light QPF. So confidence in the drizzle forming is to marginal to include in the forecast at this time. && .FIRE WEATHER... Issued at 248 PM CST Mon Feb 21 2022 Very high fire danger will continue through this afternoon ahead of a cold front where temperatures have warmed to near 70 degrees. Minimum RH values are between 20 and 30 percent for with winds between 10 and 20 mph. Winds are abruptly shifting from the southwest to the north behind the front and will continue to be breezy through the night. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Wolters DISCUSSION...Teefey AVIATION...Wolters FIRE WEATHER...Teefey
Area Forecast Discussion
National Weather Service Las Vegas NV
804 PM PST Mon Feb 21 2022 .SYNOPSIS...A strong storm system has begun to impact the region today by way of strong winds, blowing dust, and convective snows today with more opportunities for winter weather impacts through Wednesday, especially for Lincoln and Mohave counties as well as Morongo Basin. Conditions improve late week with gradual warming but breezy northerly winds heading into the weekend, especially for the Colorado River Valley. && .UPDATE...Round 1 of the winds is coming to an end as observations across much of the region show gusts diminishing below 40 mph. So, the wind advisory was allowed to expire. The exception tonight will be the western Mojave Desert and eastern Sierra slopes of Inyo County where higher gusts will likely continue. As the cold upper low over the Pacific Northwest sags south tomorrow models show Round 2, a belt of strong southwest winds develops across the western Mojave Desert extending northeast into southern Nevada. With this update will go ahead and issue a wind advisory for parts of southern Nevada and San Bernardino County. The advisory will run from 10 am PST through 8 pm PST. && .SHORT TERM...Today through Wednesday. A rather complex next 48 hours is expected across the region as a strong winter storm system swings across the southwest, drastically lowering snow levels and tapping into some Pacific moisture as it does. WIND EXPECTATIONS: Already today, impressive downslope winds have been reported over the eastern Sierra per RAWS high as 80 mph. While this has mostly stayed confined to the Sierra and not yet resulting in reaching HWY 395, we opted for an upgrade to a High Wind Warning for that zone, maintaining wind advisory for the Owens Valley. This was well reflected with the 12Z HRRR wind fields. Farther east, a strong corridor of southwest winds has developed from San Bernardino to northern Arizona. This has resulted in peak wind gusts over 60 mph for places like KIGM and resultant dust storms in Mohave County where a DSW was issued. All of these impacts are due to the passage of a shortwave to the east that will be further reinforced with much colder air behind it on Wednesday. As such, winds will continue to be a concern for tomorrow but perhaps to a slightly lesser degree as surface gradients maintain their southwest to northeast orientation but are more localized to the second pre-frontal low centered over southern Nevada. This could tighten the gradient in some places, but loosen it in others. A blend of hi-res solutions currently show max gusts tomorrow generally below Wind Advisory criteria but this may change by tonight. WINTER WEATHER EXPECTATIONS: As previously mentioned, the second round of energy from this low will be much colder and swing widely across southern California tomorrow night, enough to shift upper level winds southwesterly just before the trough axis and its strong vorticity advection slams into the mountains in San Bernardino. This will work to advect in moisture, tanking snow levels, and put Lincoln County and Mohave into a favorable RER regime of the low. What does this mean for... Morongo Basin: It means there will be a period of heavy snowfall for Big Bear overnight Tuesday into Wednesday morning where Winter Storm Warnings are in effect from SGX. With the very strong winds aloft, there is a chance this heavy snowfall will blow over into Morongo Valley and perhaps Yucca Valley, especially in the foothills and elevations above 3000ft. At this moment, deterministic values are quite low, but this is a point of high uncertainty in the forecast as probabilistic values range from trace to over 4 inches for the Morongo/Yucca Valley floors. While uncertainty is high, there are too many reasons why the higher end of the probabilistic envelope is plausible and if so, would result in accumulating snows for Yucca and Morongo. As this is all happening while snow levels are rapidly decreasing, feel a head`s up on the potential for hazardous travel is prudent. Lincoln County: Accumulating snowfall county wide, but greatest concern being HWY 93 from Caliente and north. This will be where the coldest temperatures will occur, being directly underneath the low center, but also lacking the best moisture. As the low progresses, this will put the eastern half of the county in a favorable dynamical set up for lift to tap into the moisture available and also include meager but non-zero convective potential with the low center. Latest projections did bump these values down with a more easterly, progressive track of the low though, so opted to cover this with a Winter Weather Advisory. Mohave County: Accumulating snowfall for the eastern 2/3 of the county. For all the same reason Lincoln is expected to receive snowfall, Mohave will have an even better position both dynamically and convectively relative to the parent low. Again, latest projections in the HREF and NBM have backed off some with respect to QPF, but the potential for convective banding within the RER of the low is rather good and if so, would result in locally higher amounts than those currently forecast (1-3 below 3000ft and 4-8" above). Strongest signal for this is the Arizona Strip including Colorado City and the Kaibab Indian Reservation (north of SR 389) so the higher end of those estimates may occur there, if they do at all. Farther north, that is likely to be even more of the case. Farther south in the county, accumulating snowfall also looks likely, but convective banding may not be as much of a player there. Latest NBM and hi-res guidance suggests 3-5" for I-40 east of Kingman, 1-3" for Kingman proper, and similar amounts up on the Hualapai mountains. As a result, a Winter Weather Advisory was issued for all of Mohave county from 18Z Tuesday through 00Z Thursday. .LONG TERM...Thursday into the Weekend. Most of the winter precip should be clear of the region by Wednesday night with impressive agreement among ensemble members that the low will be east of Mohave by Thursday. This will begin a period of gradual increasing temperatures heading into the weekend, but yet another shortwave is expected to push southward by Friday and temper warming as well as bring gusty northerly winds to the area, most notably at the CRV. More wind products may be on the table for this period Friday and/or Saturday. By the late weekend and into early next week, broad agreement on further warming due to ridge building appears in the cluster analysis with much quieter conditions looking more likely. && .AVIATION...For Harry Reid...Gusty southwest winds will continue with gusts to around 30-35 knots through this afternoon. Winds will relax some later this evening but may remain breezy overnight. Confidence on the forecast wind speeds and direction is moderate for tonight, with some potential for winds decreasing and shifting to the northwest briefly between 03-06Z Tuesday. By 13-14Z Tuesday, winds will increase from the south to southwest again, with similar gusts to 30-35 knots. Low level turbulence will remain through Tuesday, and low level wind shear is possible tomorrow morning- afternoon. Skies will remain mostly clear with some FEW aoa 10-15 Kft through this afternoon. Ceilings will briefly decrease tomorrow potentially dropping to around 5-7 Kft with the passing frontal system. For the rest of southern Nevada, northwest Arizona and southeast California...Gusty west to southwest winds will continue with gusts to around 30-40+ knots through this afternoon. The exception being at KBIH where gusty north winds will remain with gusts around 20-30 knots through this afternoon. Winds will relax some later this evening but may remain breezy overnight, with gusty west winds remaining across western San Bernardino impacting KDAG. Similar winds and speeds are expected to return Tuesday. SCT to BKN skies aoa 7-10 Kft will be possible with a frontal passage tomorrow. Fairly low chance for precipitation at most of the TAF sites, with best chances possible (30-40%) at KDAG. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather including strong winds, damage, dust storms, or travel impacts according to standard operating procedures. && $$ UPDATE...Pierce DISCUSSION...TB3 AVIATION...Peters For more forecast information...see us on our webpage: or follow us on Facebook and Twitter