Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/20/23

National Weather Service Bismarck ND
950 PM CST Sun Feb 19 2023 .UPDATE... Issued at 935 PM CST Sun Feb 19 2023 Snow showers have developed in southern and central North Dakota as steep mid-level lapse rates arrive with the vort max aloft. Brief periods of reduced visibility, below one mile at times, are occurring with these showers. Canadian regional radar shows snow approaching northern North Dakota this evening as well, which is expected to move through north central North Dakota through Monday morning. No changes needed with this update. UPDATE Issued at 626 PM CST Sun Feb 19 2023 Areas of light snow are crossing western and central North Dakota this evening as a mid-level impulse approaches from the northwest. Periods of briefly heavier snowfall rates are more likely in the north central, as KMOT visibility has dipped in and out of one quarter mile visibility several times. The isentropic lift driving this snow will quickly shift east through northern North Dakota, who will also see these periods of stronger snowfall rates. The track of the surface low will favor accumulating snow from north central through eastern North Dakota, as the going forecast advertises. Recent RAP guidance keeps this additional snow east of Ward and Renville counties, so no changes to the headline needed at this time. && .SHORT TERM...(This Evening through Monday) Issued at 214 PM CST Sun Feb 19 2023 The main forecast challenge for the short term period is in regards to a clipper system passing through the area. Presently light snow is falling in northwestern North Dakota. Snow will continue moving eastwards through the afternoon and evening, with another round on the backside tonight as the low passes through. Overall, two to three inches of snow is expected in the north central, with locally higher amounts possible. Moderate CAA and pressure rises will produce gusty winds. However, at this point in time, the strongest winds are focused on the west and south, and therefore do not appear to be co-located with the most snow. This may limit blowing snow once snow has fallen. However, winds should still be breezy enough to significantly reduce visibility at times while snow is falling. Therefore, the Winter Weather Advisory remains in effect. .LONG TERM...(Monday Night through Sunday) Issued at 214 PM CST Sun Feb 19 2023 The extended period will be very active Monday night through Thursday with a couple winter weather systems back to back and little to no break between them. The initial clipper system will mainly impact the west and south central Tuesday through Tuesday night in the baroclinic zone. This could lead to moderate snowfall of three to five inches over the south and west, with locally higher amounts possible. Surface high pressure passing through the Dakotas late Monday night and into Tuesday morning may help limit snowfall a bit on the eastern and northern edges and produce a tighter gradient. As high pressure slides off to the east and the incoming Colorado Low deepens, the pressure gradient will tighten and winds are expected to increase. This is where higher uncertainty creeps in because blowing snow may become a major issue, especially in the far south central. However, if aforementioned high pressure and dry air limits snow in the south central before too much falls, there may be limited snow to blow around through Tuesday night in the south central. As the Colorado Low pushes through the Central Plains Wednesday through Thursday, the area will experience its next precipitation push. This will create the potential for moderate snowfall in the south. While details are certain to change at this time, right now the most additional snow looks likely to fall in areas south of I94. Breezy winds (possibly gusty at times in the south central) look probable Tuesday night into Wednesday. Due to the complexities of this system, confidence in enhanced headlines remains low at this time. Therefore, opted to go with an SPS for now to cover moderate to heavy snow potential, along with gusty winds and potential blowing snow concerns. One final note is that very cold temperatures are returning with this system. By Wednesday, highs will be in the singles digits in most of the forecast area. Thursday night looks to be the coldest night with lows dropping into the 20s below zero. Wind chill headlines will likely be needed Tuesday night through at least Friday morning. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 626 PM CST Sun Feb 19 2023 An area of low pressure will cross the state through Monday, creating periods of MVFR/IFR ceilings and sometimes visibilities at all sites. Visibility reductions less likely at KDIK as -SN from low pressure will more likely impact KXWA-KMOT-KJMS, and possibly KBIS. Winds increase and become northwesterly early Monday morning. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 PM CST Monday for NDZ004-005-012- 013-023-025. && $$ UPDATE...AE SHORT TERM...Telken LONG TERM...Telken AVIATION...AE
Area Forecast Discussion
National Weather Service Boston/Norton MA
940 PM EST Sun Feb 19 2023 .SYNOPSIS... Overcast and rather mild conditions tonight, with fog and developing light rain showers across far southeast New England. Cloudy but mainly dry Monday with above normal temperatures. A warm front may bring a period of higher elevation snow to wintry mix Tuesday. Low pressure approaching from the southwest will bring a wintry mix Wednesday night into Thursday with perhaps a swath of modest sleet accumulations to a portion of our region. A cold front brings windy conditions followed by very cold air later Friday and Friday night. Dry and very cold Saturday but the potential for a period of snow or mixed precipitation may impact the region later Saturday and/or Sunday. && .NEAR TERM /THROUGH MONDAY/... 940 PM update... Showers increasing in coverage south of LI within a developing low level jet and higher PWAT axis. Showers are moving NE and will move up along the south coast and Cape/Islands late this evening. We nudged the PoPs a bit further NW into RI and SE MA given current radar trends and RAP indicating deeper moisture and increasing KI/TT lifting NE across the south coast. But by 06z, main focus for showers will be over Cape/Islands as moisture/elevated instability axis shifts eastward. Previous discussion... Broad, low-amplitude 500 mb wave moves through the mid-Atlc region tonight, with SSW flow allowing for a surge in moisture/PWAT values rising to 0.7 to 0.9 inches particularly into the South Coast, Cape Cod and Islands per 15z SREF mean. This ribbon of moisture should allow for lower clouds, fog and periods of showers to start developing around midnight for these areas. Remains a level of uncertainty on the northwestward extent of stratus, fog and especially showers, with today`s guidance shifting QPF axis slightly eastward. Given the rising moisture, still think Nantucket and the Outer Cape has the best chance to see rain totals around or a hair over 0.25 inches, with a tenth to two-tenths of an inch to the Cape Cod Canal and no more than a few hundredths near the South Coast. Should be dry elsewhere tonight but will remain cloudy with S/SW breezes. Low temps in the mid/upper 30s for most of CT and western/central MA, and upper 30s to lower 40s for the North Shore, eastern MA and RI. Even after showers move east early Monday, much of Monday for all of Southern New England should still feature considerable cloudiness. Outside of a rogue sprinkle or light shower, looking at dry conditions. 925 mb temps are warmer than today`s values (around +3 to +6C) and more of a WSW component to the winds could boost temps as well, but ultimately the degree of cloud cover keeps highs closer to the mid 40s to lower to mid 50s, with mid/upper 40s for Cape Cod and the Islands. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... 345 PM Update: Monday Night: Light WNW/NW sfc flow develops early Mon night as weak area of sfc ridging builds in. Consequently we do get into a period of radiational cooling with drier air coming in as well; however increasing warm advection then develops late-overnight into early Tue. More details on this below but how low we do get will have an influence on the Tue forecast (e.g. precip type at onset) for mainly in the interior and eastward to the I-495 corridor. But, more on that below. Thus a brief period of clear skies before mid to high clouds filter in on WSW flow aloft. Kept lows in the mid to upper 20s for most, though nearing the freezing mark into SE New England and the Boston, Providence and Hartford metros. Tuesday: An approximately 990 mb cyclone over the U.P of MI to bring a SE- trailing warm front into the lower Hudson Valley early Tue, with this warm frontal feature moving into SNE during the day Tue. All this said, there are a lot of uncertainties that still are not adequately resolved yet, so it is a lowered-confidence forecast. There are significant strength and timing differences amongst today`s 12z NWP, and related to this is what the temperatures will look like when precip arrives. The 12z NAM and the RGEM are slower, stronger and also somewhat earlier than are the global models (GFS, ECMWF, GEM). Current thinking is for a mid-morning to late afternoon timing, and while rain should predominate at onset west of I-495 and along and S of Rte 6 in CT and RI with temps in the mid 30s (and slowly rising), further in the interior precip looks to begin as a period of steady light snow given sufficiently cold enough temps at onset. Gradually warming temps should facilitate a transition from wintry precip to rain, though indications for a possible secondary low pressure, later in the day, to back the sfc winds to more of a NEly flow, and that could lead to a longer period of frozen precip mainly into the Merrimack Valley, northern hills of Worcester County and possibly into the Berkshires. This might be because of its mesoscale nature, but due to robust frontogenesis, the NAM shows some 30 microbars of omega right in the snow growth region for a couple of hours for areas north of the Mass Pike Tue late-AM to early-PM. That could force bands of higher-snow rate/lower-visby snow. But, as mentioned the global models are more muted and also later than the NAM/RGEM. Approach that was taken was a more higher-elevation favored minor snow accumulation of 1 to up to 3" for the Berkshires, and northern Worcester Hills with minor coatings south and east to around I-495/I- 84 corridor. Most of these totals ultimately get washed away by rain as well. Thus took a more conservative approach and currently thinking a sub-Advisory, higher-elevation favored snowfall. If the global models come in a little stronger and/or the NAM/RGEM keep their robust depictions, then accumulations could need to be increased. Clouds/precip will offset warm advection; sided highs a little on the colder end of guidance but not as cold as the NAM. Highs mid 30s for the hills, and the upper 30s to lower 40s in the valleys, coasts and cities. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Highlights... * Wintry mix Wed night-Thu...perhaps a swath of modest sleet accums? * Windy & turning quite cold later Fri-Fri night * Diminishing winds but still very cold on Sat * Perhaps a period of overrunning snow/mix later Sat and/or Sun Overall Pattern... Quite the complex and active weather pattern into next weekend. Strong upper level ridging over the Gulf/Caribbean will continue to result in above normal heights/temps across the southeast. Meanwhile...anomalous closed upper level low over Hudson/s Bay will allow very cold/below normal temps to impact Canada and much of the far northern U.S. This sets up a very large temp gradient from north to south and our region will be in the battleground. Although at least at the surface temps will likely run below normal given the push of shallow cold air. This will also set the stage for overrunning precipitation events...with the main concern right now focused on Wed night into Thu. However...there is the possibility for another overrunning event sometime next weekend although that is more uncertain. We will break things down a bit more below. Details... Tuesday night into Wednesday... Any lingering light precipitation will be exiting the coast by mid- evening Tue if not earlier. Otherwise...a ridge of high pressure brings dry weather for most of Tue night into most of Wed afternoon. Low temps mainly in the 20s to around 30 Tue night with highs Wed in the upper 30s to the middle 40s. Wednesday night and Thursday... Quite the interesting setup Wed night into Thu as large sprawling high pressure sets up across central and eastern Canada. This will allow shallow cold air to ooze down into our region from eastern Canada. At the same time...a wave of low pressure across the central U.S. lifts northeast towards the eastern Great Lakes. This will spawn weak secondary low pressure south of our region. The result of this will be an overruning precipitation event Wed night into Thu. Shallow/Dry cold air oozing down from the north will allow for wintry precipitation. However...above normal height fields being pushed up from the south will result in a developing warm nose aloft. This type of setup is not favorable for an all out snowstorm. While there may be some snow especially at the early look at the soundings indicate the potential for perhaps a decent amount of sleet and perhaps a bit of freezing rain too. Still need a lot of time to sort out...but may have an area of modest sleet accumulations? Would say there is very good chance we need some Winter Weather Headlines Wed night into Thu for a wintry mix. Given very cold air to our north coupled with a wave of low pressure undercutting us...guidance likely too warm with high temps Thu especially across the interior based on pattern recognition. Friday and Friday night... A strong cold front crosses the region on Friday. This will bring windy and very cold temps later Fri into Fri night. High temps may top out mainly in the 30s Friday bit if that happens will be turning much colder later Fri into Fri night. It will also become windy with NW wind gusts of 25 to 40 mph and perhaps even flirting with wind advisory criteria in a few spots. Low temps Fri night will be down into the single digits to lower teens with wind chills below zero! Dry weather across most of the region...but may have some ocean effect snow showers develop across parts of the Cape with very cold NNW flow. Next Weekend... Winds diminish by Saturday as large high pressure builds in from the west...but it will still be very cold. High temps Sat only in the 20s to around 30. We may have a period of overrunning snow/mix sometime late Sat or Sun...but confidence on if that occurs is rather low. Models have backed off a bit on what they depicted 24 hours ago...but some of the GEFS/EPS ensembles still indicating this potential. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 00Z TAF Update... Tonight: High confidence in trends, moderate in timing and northward extent of lower ceilings. Mainly VFR this evening but some brief/localized marginal MVFR ceilings are expected. Conditions then deteriorate to IFR-LIFR ceilings Cape and ACK after 08z with a brief period of scattered rain showers and fog. S winds around 5-12 kt, with low-20s kt gusts Cape/ACK. Uncertain on the northwest extent of widespread lower ceilings...but expect BOS-PVD points north and west to generally remain above IFR thresholds but a period of MVFR ceilings are possible. Monday: High confidence. MVFR-LIFR ceilings, areas of rain showers Cape Cod, to gradually improve from NW to SE ~12-16z. BKN-OVC VFR ceilings with low prob of a shower thereafter. SSW winds around 10 kt, then shift to W 6-8 kt late day. Monday Night: High confidence. VFR. Increasing coverage of mid to high clouds after midnight, continuing to lower by pre-dawn but should still be in the VFR range. W/NW winds 6-10 kt ease and then become NE/ENE late. Tuesday: Moderate confidence. Early VFR deteriorates to MVFR-LIFR with rain and higher elevation accumulating snow, transitioning to all rain late. ESE/E winds become S late.KBOS Terminal...High confidence in TAF. MVFR cigs for a short period 08-11z but otherwise mainly OVC VFR. KBOS Terminal...High Confidence in TAF. Period of MVFR ceilings possible roughly in the 6z to 12z time frame...but favoring IFR conditions remaining south of the terminal. KBDL Terminal...High confidence in TAF. Outlook /Tuesday Night through Friday/... Tuesday Night: Mainly VFR, with local MVFR possible. Strong winds with areas of gusts up to 40 kt. Wednesday: VFR. Windy with local gusts up to 30 kt. Wednesday Night: Mainly IFR, with local MVFR possible. Breezy. RA, chance SN, PL likely, chance FZRA. Thursday: Mainly IFR, with areas MVFR possible. Windy with gusts up to 30 kt. RA, PL, chance FZRA. Thursday Night: Mainly IFR, with areas MVFR possible. Windy with local gusts up to 30 kt. PL likely, chance RA, chance SN, chance FZRA. Friday: Mainly VFR, with local IFR possible. Strong winds with local gusts up to 40 kt. Slight chance SHSN. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 355 PM Update: Through Monday Night: High confidence. SCAs remain in effect. S winds to continue to increase rest of the aftn and tonight with gusts 25-30 kt, with gusts easing toward daybreak. Will have developing rain showers SE coastal and offshore waters with intervals of patchy fog reducing visby. SW winds 15-20 kt Mon turning W/NW and easing toward evening with modest seas 3-5 ft. Tuesday: Moderate confidence. Winds become E/ESE and increase to 10-20 kt, perhaps with gusts near SCA levels later in the day as winds flip to W late. Outlook /Tuesday Night through Friday/... Tuesday Night: Low risk for gale force winds with gusts up to 35 kt. Seas up to 5 ft. Wednesday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Wednesday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Seas locally approaching 5 ft. Chance of rain, sleet likely, chance of snow. Areas of visibility 1 to 3 nm. Thursday: Low risk for gale force winds with gusts up to 30 kt. Areas of rough seas. Rain, sleet likely. Local visibility 1 to 3 nm. Thursday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain, chance of freezing rain. Local visibility 1 to 3 nm. Friday: Moderate risk for gale force winds with gusts up to 40 kt. Rough seas up to 9 ft. Chance of snow showers. Visibility 1 to 3 nm. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 3 AM EST Monday for ANZ231>235-237- 251. Small Craft Advisory until 7 AM EST Monday for ANZ250. Small Craft Advisory until 7 AM EST Tuesday for ANZ254>256. && $$ SYNOPSIS...Frank/Loconto NEAR TERM...KJC/Loconto SHORT TERM...Loconto LONG TERM...Frank AVIATION...Frank/Loconto MARINE...Frank/Loconto
Area Forecast Discussion
National Weather Service Des Moines IA
535 PM CST Sun Feb 19 2023 ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Sunday/ Issued at 318 PM CST Sun Feb 19 2023 Key Messages: -Warm and breezy tomorrow then cooler Tuesday -Snow in the far north on Tuesday night into Wednesday -Another system bring rain/snow/wintry mix on Wednesday into Thursday Temperatures in much of Iowa have warmed into the mid to upper 40s by mid day. However, across the north a thick stratus deck is sagging down into the state and stopping any additional solar heating in the area. This morning, models were indicating a chance for some fog development overnight tonight but have since begun to trend down on these chances. Recent soundings show the surface struggling to reach saturation as cloud cover negates radiational cooling. HREF guidance still shows a low probability for patchy fog tonight, as well as some deterministic models, so have decided to leave some fog in the forecast over east central Iowa, should any clearing develop beneath the high pressure. Those with clear skies will continue to warm through the afternoon, with satellite showing last weeks snow slowly eroding from south central Iowa. Less snow on the ground should help to boost temperatures tomorrow as another wave moves through and southerly flow kicks back in. Cloud cover tomorrow will once again inhibit solar heating, especially in the north, but breezy conditions and warm southerly flow will help to pick up the Sun`s slack in those cloudier areas. This wave moves through rather quickly, and cold air advection once again moves in tomorrow afternoon, bringing breezy conditions with it tomorrow night. The 18z HRRR has begun to develop a quick shot of light rain/snow through central and northern Iowa ahead of this cold front. The surface looks to be a bit starved for moisture, so it would be tough to get much precipitation out of it, but a few raindrops or snow flakes may fall along this boundary should more moisture get advected in at the surface. After Monday, we look ahead to a quite active week for the upper plains and Midwest. The first of this activity will begin on Tuesday afternoon as a frontogenetic zone sets up across southern Minnesota and far northern Iowa. A less traditional source of moisture will move in from the pacific northwest and combine with strong forcing to drop snowfall over much of the northern plains. This snowfall will be primarily centered just north of the strongest frontogenetic forcing and north of the Iowa/Minnesota border. However, 12z GFS guidance has shown this zone leaking slightly further south, resulting in higher snowfall amounts along the border and into our northern counties. The cutoff along this area will be fairly sharp, so it`s tough to say quite yet whether significant snow will make it south into the state with this first round, but snowfall in the far north is likely on Tuesday night into Wednesday. A low pressure system will then lift north into the state on Wednesday, bringing more widespread precipitation to the area. This precipitation will range from rain in the south to snow in the north, with a wintry mix falling in between through north central Iowa. This system will bring in additional moisture from the gulf and phase with the frontogenetic zone and pacific moisture to the north, resulting in a prolonged period of moisture to the north. Fortunately, it seems that this phasing will have a slight lull in our area, giving those in northern Iowa a brief break from the snow before the low moves north. However, should the initial zone continue to sag further south, could potentially see quite significant snowfall in the far north as these systems phase Tuesday through Thursday. With both these systems still being a few days out, there is still time for things to shake up a bit, so will continue to monitor and message any changes with either of these precipitation chances. && .AVIATION.../For the 00Z TAFS through 00Z Monday evening/ Issued at 533 PM CST Sun Feb 19 2023 Eroding MVFR stratus will be over northern Iowa early in the period. Another round of MVFR or lower stratus and/or fog is possible over KMCW/KALO/KFOD later tonight and into Monday morning. VFR conditions should persist at KDSM/KOTM. Diminishing northwest wind tonight will become southerly by early Monday morning and breezy/gusty in the afternoon. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Dodson/Cogil AVIATION...Donavon
Area Forecast Discussion
National Weather Service Grand Forks ND
1005 PM CST Sun Feb 19 2023 .UPDATE... Issued at 957 PM CST Sun Feb 19 2023 850 mb warm advection driven light snow into eastern ND this evening as expected. Rates of snowfall have been a bit lower than perhaps thought, but there are areas of moderate snow and radar returns indicate pockets of moderate intensity snow south of Devils Lake to New Rockford then toward Cooperstown. On social meida report of near 2 inches around Oberon south of DL, radar would show 1-2 inches in that area. Snow does extend up thru Bottineau where its AWOS has been under 1 mile vsbys for a 1-2 hour period. Did adjust pops for likely snow all night from GFK west-northwest to Bottineau region. Main sfc low is southwest of Regina SK and upper wave and pockets of moderate snow with that noticed on Canadian radars between Regina and Prince Albert SK. This snow with the upper wave will be over the Red River valley toward 18z Monday. So we got some snow yet to get through, so will maintain snow forecast as is. Most will likely be on the lower end of the snow forecast, but as we have seen pockets of higher snow will occur. UPDATE Issued at 610 PM CST Sun Feb 19 2023 Light snow into Devils Lake at 00z and upstream observations indicate moderate snowfall at times back to Minot and Stanley ND. Minot radar is down so hard to pick up on the extent of snowfall in north central ND other than thru obs. HRRR indicates main snow area along Hwy 2 this event if we look into Monday. Probably more in waves than long lasting heavy snow. Will adjust pops as needed this evening. && .SHORT TERM...(This evening through Monday night) Issued at 250 PM CST Sun Feb 19 2023 Overview: Impacts are expected overnight through Tuesday morning as a clipper system moves through southern Canada into the northern plains. High signal for 2+ inches of snowfall across the Highway 2 corridor, with impacts possible within heavier snow bands associated with the frontogenesis. Impacts from blowing/drifting snow are expected during the morning and evening commutes Monday. Accumulating Snow: Strong system shifts through the northern plains tonight through Monday, with accumulating snow developing along the line of frontogensis. Signals have the system bringing 2+ inches of snowfall along the highway 2 corridor, with up to 5 inches possible. Areas along and south of Highway 200 will see a sharp cut off thanks to the frontogenetic feature of the system. So areas south of Highway 200 could see up to 2 inches (40-50% chance). Isolated higher amounts toward 6 inches can`t be ruled out especially in higher frontogentic bands creating higher snowfall rates around the Highway 2 corridor. Potential is out there that we could see higher snowfall rates of 1 inch per hour, but that probability is roughly 20-30% across the Highway 2 corridor. Areas in higher snowfall rates combined with winds around 10-15kt could create reduced visibilities down to 1/2 a mile at times. Wind and Blowing Snow: The system translates across the region fairly progressively, with a pivot near the central Red River valley. As the system moves through the valley, strong cold air advection wraps around in central ND and the Devils Lake Basin. Guidance from the HRRR/NAM/RAP all indicate a strong surge of winds around the cold front. Momentum transfers are strong, cold air advection is noted, and pressure changes are high over several hours. Timeframe for the cold front is within the morning hours on Monday. Strong winds combined with the freshly fallen snow brings reduced visibilities across portions of the forecast area. Any shift in the track to the north or south can shift the higher winds further north or south, but the likelihood (70%) is that the highest winds behind the cold front will be situated in SE ND back towards the James River Valley. Wind gusts along the front could gust up to 40mph at times. This doesn`t look to be a long duration as the HRRR and RAP have the front moving through within a couple of hours. This will affect areas where the recent snowfall is potentially less than 2 inches limiting some of the impacts from the blowing snow. Near blizzard conditions wills till be possible at times (40-50%)in open country as the cold front shifts through. Duration of the strongest winds is medium in confidence as there is the possibility they could last over the 3 hour mark (30%), but likely will not. This however could potentially prolong the impacts for the southern Red River Valley. None the less, blowing snow impacts are expected Monday morning in the southern Red River Valley creating minor to potential moderate distributions to daily life. After the initial surge of cold air from the cold front, winds will shift toward the north creating a more funneling effect down the valley. Winds then have the potential to gust up to 30mph within the valley Monday afternoon and into the early morning hours on Tuesday. This combined with the recent snowpack in the northern valley creates blowing snow impacts. Visibilities may be restricted down to 1/2 a mile at times away from urban centers. The severity of the blowing snow impacts are less certain during the evening and overnight hours due to the strength of the winds. Sustained winds are around 20-25mph and gusts near 30mph at times. This would give the probability of 30-40% of near white our conditions for open country areas within the Red River Valley. To increase those chances the pressure changes would need to be greater and cold air advection stronger. However, blowing snow is expected and will create minor to moderate impacts during the Monday evening commute. Anywhere outside of urban areas has that potential for near blizzard conditions at times. Conditions improve as we head into the sunrise hours on Tuesday, with cold morning temperatures expected. .LONG TERM...(Tuesday through Sunday) Issued at 250 PM CST Sun Feb 19 2023 Active weather through with potential for winter travel impacts Tuesday through Thursday due to large storm system bringing multiple rounds of snow/blowing snow potential. It remains consistent with the highest winter impacts and snow amounts to remain to the south of the forecast area into South Dakota and Minnesota. Two rounds of snow can be expected with this system as it moves through, with the first coming mainly Tuesday with the WAA portion of this system as it deeps across the western high plains. The northern edge of this swath of snow could lift into far southeastern ND and west central MN bringing around 2 to 4 inches of snow. Dry air moving into this system with northeasterly flow likely to produce a tight gradient between areas of no snow, and moderate accumulations. Therefore uncertainty exists in where that northern edge of snow will be. Currently probabilities of snowfall from Tuesday into Tuesday evening are around: 2" (50-80% from I-94 southward) 4" (30-50% across Ransom, Sargent and Richland Counties). Winds increase across the ND portion of the forecast area Tuesday night into early Wednesday which could result in areas of blowing snow and near blizzard potential along and south of Hwy 2. Currently projections of around 25-30 mph sustained winds with gusts to 40 mph possible Tuesday evening into Wednesday morning. The second round of snow with this system is expected to spread across the area late Wednesday into Thursday, with the greatest chance for snow accumulations again remaining across the southern third of the forecast area. The main sfc low is expected to track from central MO late Wednesday into WI by Thursday. Wrap around precipitation to nudge back into ND/MN with a strong pressure gradient setting up across MN/IA/SD into ND. This portion of the system has a greater chance of bringing moderate to heavy snow to far southeastern ND and west central MN. Gusty winds across the area Wednesday night also the potential for near blizzard conditions, especially in areas with falling snow. Lots of uncertainties with small movements in the track of this system and how the dry air impacts that northern edge of snowfall on for both rounds of anticipated snow. Therefore will hold off on any watch headlines at this time. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 610 PM CST Sun Feb 19 2023 Aviation flying conditions tied mostly to visibility in snow with our system tonight into Monday. Also areas of MVFR cigs. Vsbys will be changeable but expect a majority MVFR/IFR conditions later tonight into Monday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...Winter Weather Advisory until 9 PM CST Monday for NDZ006>008- 014>016-024-026>030-039-054. MN...Winter Weather Advisory until 9 PM CST Monday for MNZ001>009- 013>017-022>024-027-028-032. && $$ UPDATE...Riddle SHORT TERM...Spender LONG TERM...MJB AVIATION...Riddle
Area Forecast Discussion
National Weather Service Jacksonville FL
828 PM EST Sun Feb 19 2023 ...New UPDATE... .UPDATE... Issued at 825 PM EST Sun Feb 19 2023 Broad sfc high pressure was located over the north central Gulf of Mexico around 1024 mb at 8 PM, with ridging also over the western Atlantic. The pressure gradient today was weak enough for the east coast sea breeze to move well inland and provide some boost to the low level moisture for the eastern zones. With the pressure gradient weak, winds are dropping to about 5 mph or less with temps now in upper 50s to lower 60s. Most of the stratocumulus clouds have decrease and pushed well offshore, and should continue to see scattered to broken high clouds through the night based on latest satellite imagery. Min temps in the upper 40s into the 50s expected tonight, and little change needed at this time. The main impact tonight will be fog, with some areas of dense fog possible late tonight into Monday morning over the Suwannee Valley area. This is in best agreement with the HRRR and HREF guidance. Could also see some brief patchy fog toward midnight along the east coast before some boundary layer flow switches back to the southwest along the coast later tonight. && .SYNOPSIS... Issued at 512 PM EST Sun Feb 19 2023 Late afternoon surface analysis depicts a weak coastal trough lifting northeastward towards the Gulf Stream waters off the southeast GA coast. Meanwhile, high pressure (1026 millibars) was building eastward along the Interstate 10 corridor from the northern Gulf coast. Aloft...flat ridging continues to expand over the Gulf of Mexico towards the FL peninsula, creating brisk zonal flow across our region, and this ridge is deflecting shortwave energy emerging from the northern Rockies east-northeastward across the northern Plains states towards the western Great Lakes. Weak isentropic lift associated with the departing coastal trough has created an area of thicker stratocumulus cloudiness for locations along and east of I-75 in northeast and north central FL, with this cloudiness moving eastward along the I-95 corridor this afternoon. Our lower troposphere remains far too dry for any shower activity, with the Melbourne (KMLB) radar indicating showers developing over the Gulf Stream waters well offshore along the departing coastal trough. Temperatures reached the 70s at most inland locations this afternoon, with a few locations touching 80 degrees before the stratocumulus deck arrived. However, the Atlantic sea breeze boundary pushed onshore early this afternoon, keeping coastal highs generally in the mid to upper 60s. This boundary crossed I-95 late this afternoon. && .NEAR TERM... (Tonight and Monday) Issued at 512 PM EST Sun Feb 19 2023 Coastal troughing will lift northeastward and further away from our area this evening, taking the stratocumulus deck with it as deep-layered ridging builds over our region. Thin cirrus cloudiness will invade our skies from west to east overnight, with light westerly flow prevailing in the low levels. Developing warm air advection will likely push a stratus layer onshore along the FL Big Bend and Nature coasts after midnight, with this stratus and locally dense fog then expected to advect across northeast and north central FL, especially for locations south of I-10, during the predawn and early morning hours. Decreasing cloud cover this evening and decoupling surface winds should allow lows to fall to the upper 40s to around 50 at most inland locations, ranging to the low and mid 50s at coastal locations. Low stratus ceilings and locally dense fog over northeast and north central FL will quickly dissipate by the mid-morning hours on Monday as west-southwesterly flow deepens across our area, with breezy conditions expected nearly area-wide during the afternoon hours. A dry air mass and mostly sunny skies will combine with rising heights aloft to boost highs to the upper 70s and lower 80s at most locations, and the brisk low level flow should prevent the Atlantic sea breeze from progressing onshore, allowing highs to climb well into the 70s all the way to area beaches on Presidents` Day. && .SHORT TERM... (Monday through Tuesday night) Issued at 512 PM EST Sun Feb 19 2023 Deep-layered ridging will continue to control our local weather pattern, with brisk westerly flow around the boundary layer on Monday night likely preventing significant fog formation. Westerly surface winds of 5-10 mph will likely keep lows in the 55-60 degree range area-wide. A weak shortwave embedded within the brisk westerly flow aloft is progged to traverse north and central GA on Tuesday afternoon, but our low levels will likely remain too dry for shower activity in southeast GA. Otherwise, breezy southwesterly winds will push highs to the 80-85 degree range inland and 75-80 at coastal locations, where a weak sea breeze may push onshore by late afternoon due to surface ridging weakening as it crosses the FL peninsula. This weakening surface ridge may allow for low stratus ceilings and fog to develop across our area by late Tuesday night. Lows again will only fall to the 55-60 degree range throughout our region. && .LONG TERM... (Wednesday through Saturday Night) Issued at 512 PM EST Sun Feb 19 2023 Deep-layered ridging will become quasi-stationary over south FL, deflecting shortwave energy from Texas and the lower Mississippi Valley northeastward through the Tennessee and Ohio Valleys on Wednesday and Wednesday night. Strengthening subsidence will keep dry and unseasonably warm weather in place locally from Wednesday through Friday, with daily and possibly monthly record high temperatures being challenged (see Climate Section below for details), as highs generally climb to the 85-90 degree range inland and the lower 80s at the coast. The deep-layered ridge will flatten by late in the week, possibly allowing a "backdoor" cold front to slide down the southeastern seaboard on Friday night. This front will likely stall near the FL/GA border by Saturday and may then lift back to the north by late in the weekend. We did nudge forecast lows slightly below long-term consensus MOS guidance during this time period due to strong subsidence and the likelihood of radiational cooling as surface winds decouple each evening, but lows in the upper 50s and lower 60s are still well above climatology for late February. && .AVIATION... (00Z TAFS) Issued at 630 PM EST Sun Feb 19 2023 VFR conditions into this evening and late tonight, but increasing moisture off the Gulf of Mexico and light winds will enable some fog/mist to form over the inland northeast FL area after midnight and into Monday morning. These vsby/cig issues are forecast to affect GNV terminal, and based on latest probs have included a possible LIFR cig Monday morning. In addition, some moisture off the Atlantic today that affected SSI and SGJ may provide some opportunity for a brief period of mist and a low ceiling but confidence on this is not high at this time. Otherwise, some MVFR vsby at the more fog prone VQQ terminal late tonight. As any stratus and fog/mist dissipate Monday morning, VFR clouds expected with some few-scattered cumulus and high clouds. A light and variable wind this evening goes light to calm tonight. Winds return to a west to southwest direction at about 6-12 kt on Monday after 14Z with some gusts to near 20 kt possible. Slight backing of wind for SGJ and SSI in the aftn due to a sea breeze influence. && .MARINE... Issued at 512 PM EST Sun Feb 19 2023 Weak coastal troughing over the offshore waters will lift northeastward and away from our region this evening as high pressure situated along the northern Gulf coast builds southeastward. This weather pattern will create gradually strengthening west-southwesterly winds overnight, with speeds possibly approaching Small Craft Advisory levels around 20 knots over the offshore waters on Monday night. Speeds are expected to increase to 15-20 knots for the near shore waters by sunset on Monday evening. Seas will peak in the 4-6 foot range offshore on Monday night and Tuesday morning before falling below Caution levels by Tuesday afternoon. Seas near shore are expected to remain in the 3-4 foot range through Tuesday morning before settling back to the 2-3 foot range for the remainder of the week. High pressure will then weaken and push eastward across the Florida peninsula on Tuesday, moving offshore on Tuesday night and Wednesday. Prevailing southerly winds are forecast by midweek, and winds are then forecast to shift to a more westerly direction late this week as a weak frontal boundary pushes down the southeastern seaboard. This front should stall across our local waters by Saturday, resulting in winds briefly becoming onshore before the front lifts northward by late next weekend. Seas of 2-4 feet will prevail offshore during mid and late portions of this week. Rip Current Risk: A lingering easterly ocean swell on Monday will likely keep a low-end moderate rip current risk in place at area beaches. Breezy offshore winds will likely result in a low risk on Tuesday and Wednesday. && .FIRE WEATHER... Issued at 512 PM EST Sun Feb 19 2023 West-southwesterly surface and transport winds will strengthen shortly after sunrise on Monday, with breezy conditions expected during the afternoon hours, resulting in good daytime dispersion values at most locations. A dry and increasingly warm air mass will result in minimum relative humidity values falling to the 30-35 percent range during the afternoon hours throughout southeast Georgia and for all locations east of the Interstate 75 corridor in northeast and north central FL. Transport winds will remain breezy on Monday night, possibly creating elevated nighttime dispersion values across our region. Breezy westerly surface and transport winds are forecast on Tuesday, with good daytime dispersion values expected. Surface and transport winds may then weaken slightly and should shift to south-southwesterly by midweek. && .HYDROLOGY... Issued at 512 PM EST Sun Feb 19 2023 Water levels continue to rise along the Alapaha River near the Statenville gauge, and minor flooding will likely begin around this gauge in the Suwannee Valley by Tuesday or Wednesday. Otherwise, minor flooding will continue through at least midweek along upper portions of the Altamaha River. Water levels have crested or have fallen just below flood stage along middle and lower portions of the Altamaha. Minor flooding will also continue during the entire week along lower portions of the Satilla River near the Atkinson gauge. Otherwise, water levels upstream on the Satilla near Waycross have fallen below flood stage. && .CLIMATE... Issued at 512 PM EST Sun Feb 19 2023 Daily record high temperatures from Wednesday through Friday at our designated climate sites: Wed 2/22 Thurs 2/23 Fri 2/24 ----------------------------------- Jacksonville 87/2019 85/1962 88/1962 Gainesville 88/2019 91/2019 88/1962 Alma, GA 84/2019 84/2018 85/2018 St. Simons Island 81/2011 82/2012 84/2012 Craig Airport 86/2019 85/2012 86/2012 All-time records for the month of February at our designated climate sites: Jacksonville 89 2/13/2020 Gainesville 91 2/23/2019 Alma, GA 87 2/21/2018 St. Simons Island 85 2/28/1962 Craig Airport 87 2/18/2021 && .PRELIMINARY POINT TEMPS/POPS... AMG 47 78 57 83 / 0 0 0 10 SSI 52 74 59 76 / 0 0 0 0 JAX 50 81 58 83 / 0 0 0 0 SGJ 54 79 59 82 / 0 0 0 0 GNV 50 80 57 83 / 0 0 0 0 OCF 50 80 57 83 / 0 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$