Aikyam-Lab/Synoptic-Bench huggingface dataset:
Light NW flow on back side of low pressure off Florida East coast could contain enough moisture for a period of ceilings in the 400-900 ft range at all terminal sites during the aforementioned time frame. /issued Issued by National Weather Service Key West FL/ Currently - A broad low pressure system centered east of the Florida peninsula is resulting in gentle to moderate mostly west breezes. Shower activity has trended downwards through the afternoon hours as surface dew point depressions increased and drier air continues to move in through the lower to mid levels.
Even though the far southwestern forecast zones, including I-90 in Jones and Lyman counties, are located where it is tough for area 88D's to "see" falling snow, model cross sections indicate that dry air entrainment (between 850hpa and 500hpa) does not quite reach all the way down to Jones/Lyman counties yet, so confident enough to continue the high end pops for some light qpf and snowfall amounts there through appx midnight. Otherwise, expecting some breezy/gusty northerly winds tonight and through the day Friday on the back side of the low pressure system.
Memphis may remain in the low 60s. Temperatures range from the lower 70s in northeast Mississippi to the upper 70s across the Mississippi River Delta.
Low stratus will begin to advect northward after midnight ahead of an approaching cold front.
Trough axis will move into the Brush Country overnight with winds becoming light over the coastal plains and gradually veering. Dewpoint temperatures are in the lower 60s right behind the sea breeze boundary and near 70 along the coast. Winds will become light after midnight as trough axis moves into the eastern Brush Country. The trough axis will move through the coast early Friday morning ahead of the frontal boundary moving into the Brush Country.
805 PM EST Thu Feb 23 2017 Early evening water vapor satellite imagery is showing the broad cyclonic circulation from the upper level low pressure just north of the Bahamas, with rather dry air aloft over the Florida Peninsula wrapping around on the west side. Although the wind direction along the coast remains largely northerly, buoys just offshore are still showing a west direction to the swell, and the high risk of rip currents will continue into tonight before the winds and waves subside enough to minimize the threat.
These conditions should im- prove by 15Z tomorrow, with the cold front moving into the NRN parts of the area (CLL) just after noon. /ISSUED 336 PM CST Thu Feb 23 2017/ Above normal temperatures will continue until a cold front moves through Southeast Texas tomorrow.
Mid level lapse rates continue to steepened in response to the upper level low progressing from northern Colorado into western Nebraska. High temperatures for Friday will occur at midnight, with afternoon temperatures ranging from the low 30s in the north to low 40s in the southern areas. The bulk of precipitation associated with upper level low in Nebraska is expected to stay north of the area. With surface temperatures hovering near freezing, I have introduced a couple hours of light freezing drizzle. Pavement temperatures are well above freezing across the entire area, therefore expect minimal accumulation and impacts to roads.
An upper low over the upper MS valley will depart the area Fri night and bring zonal flow aloft to the region Fri night into Sat. Will remove the likely POPs in the late Tue aftn and early evening hours while keeping the highest POPs across w central MN late Tue night. With the cooler weather forecast may change.
401 PM CST Thu Feb 23 2017 (Tonight and Friday) An upper level trough will track east from the Rockies and across the central Plains tonight, with an associated cold front dropping south across the area after midnight. Aforementioned front will usher in a dry and cooler airmass for Friday, with afternoon highs still above normal but about 20 degrees cooler than today, with highs in the upper 60s and lower 70s.
323 PM PST Thu Feb 23 2017 Any snow showers will dissipate tonight as high pressure briefly builds over northeast California and western Nevada.
625 PM EST Thu Feb 23 2017 Low pressure centered in the Bahamas will be moving farther off the Southeast Coast Friday.
After highs well into the 70s areawide today, even warmer temperatures are on tap for Friday. A cold front will be quickly approaching the area by Friday night, which will bring increasing rain chances for north Georgia.
These conditions should im- prove by 15Z tomorrow, with the cold front moving into the NRN parts of the area (CLL) just after noon.
VFR conditions expected throughout the night with high pressure over the area.
An approaching cold front may result in some BR prior to frontal passage forecast to reach the I-35 terminals just before dawn. Upper air analysis this morning showed nearly zonal flow across the southwestern US with a trough over the northern Rockies. At the surface, high pressure was centered over the Gulf and winds were from the southeast to southwest. The upper level trough over the northern Rockies will swing down through the southern plains. A cold front will move through north Texas tonight and our CWA Friday morning. Temperatures will be cooler behind the front, but still above normal.
435 PM MST Thu Feb 23 2017 Upper low is spinning over south central WY, pushing snow north into the CWA. Expecting another 3-8 inches of snow overnight in the warned areas, with the higher amounts across south central SD.
Upper low is spinning over south central WY, pushing snow north into the CWA. Expecting another 3-8 inches of snow overnight in the warned areas, with the higher amounts across south central SD.
315 PM MST Thu Feb 23 2017 Upper level elongated trough will continue to move eastward through Friday with the jet staying to the south. Temperatures will remain below freezing with highs today only reaching into the lower 30s dropping into the teens overnight. Temperatures will continue to be cooler with highs only in the mid to upper 20s for Friday. Upper low over Nebraska is progged to slowly track east gradually losing its grip on northeast Colorado.
838 PM MST Thu Feb 23 2017 Snow rates have diminished across much of the region as the upper low steadily weakens overhead, however a few areas of heavier snow showers remain across the forecast area. However, very icy conditions are possible here tonight with cold temperatures likely freezing today's wet and slushy snow to roads so impacts are still non- negligible. A few below zero readings are possible in the high country as well. Latest water vapor loop was showing a very elongated upper level trof stretching from the intermountain west east towards the high plains. The upper low deepens over the central Plains Friday with snow rates diminishing east of the Laramie Range mid to late morning while persisting through the afternoon out west across Carbon and Albany counties.
Upper ridging to build into the E Gulf from the SW Gulf/NW Carib tonight then up over the region Friday. At the start of the period upper and surface ridging over the region will support dry weather with above normal temperatures.
Temperatures will drop to freezing levels over much of the San Joaquin Valley tonight. Broad upper trough still covers much of the western CONUS with a few light showers over the southern Sierra foothills. Freezing temperatures are forecast across much of the San Joaquin Valley, thus a Freeze Warning has been issued. 3-6 hours of freezing temps are forecast with some rural areas dropping to around 28 degrees. Temps should nudge up a bit Friday night but some areas are still likely to reach the freezing mark. There a couple short wave troughs progged to swing through from the north, thus they will have lower snow levels, generally around 3-4K feet.
The exception will be to keep the High Wind Warning going for the Guadalupe Mountains through Friday afternoon where winds aloft will remain strong through Friday afternoon. As the upper system moves northeast of the forecast area the associated surface Pacific cold front will move through the region tonight, bringing cooler temperatures overnight and Friday.
455 PM MST Thu Feb 23 2017 A much colder airmass has settled over the area under a broad trough of low pressure aloft. There is also a mid level low pressure center over southern WY and circulation around this will keep a favorable upslope northerly wind into the Uinta Mtns through tonight. As the main upper level trough shifts east over the Plains Friday, flow becomes northwesterly and lightens.
Slight adjustments will be made to hourly temp/dewpt grids, but lows are still expected to be in the lower to mid 50s.
537 PM MST Thu Feb 23 2017 Latest water vapor loop was showing a very elongated upper level trof stretching from the intermountain west east towards the high plains. The upper low deepens over the central Plains Friday with snow rates diminishing east of the Laramie Range mid to late morning while persisting through the afternoon out west across Carbon and Albany counties.
650 PM CST Thu Feb 23 2017 At H5 Upper closed low over eastern Wyoming with winter storm over northern plains. Closed low off florida coast and closed low over the southern Hudson Bay with storm moving across Northeast CONUS. Had some reports over southwest Nebraska of freezing precipitation early this afternoon but threat has diminished. Upper low over eastern Wyoming with energy rotating to the northeast across western Nebraska.
A cold front will move into the state from the west during the early morning hours tomorrow.
The main concern for the forecast period will be in the short term as a cold front passes through tomorrow evening. GFS does try to produce some activity with the prefrontal trough but more likely, the front will be needed to trigger activity.
However, a cold front will move across all terminal sites this evening, with gusty north winds for a few hours or so in its wake. /Issued 304 PM CST Thu Feb 23 2017/ Broad upper level trough with strong mid and upper level jet currently located over the Great Basin. Decoupling is expected to take place around 00z-01z and will help to reduce wind speeds ahead of the cold front.
Southerly flow is increasing today as a strong cold front inches its way toward the mid state. A warm front has developed north of the Ohio Valley, placing Middle Tennessee under a near-record warm air mass that will persist through tomorrow. The cold front won't pass through Middle Tennessee until Friday evening, and we likely won't see any precipitation until after 00Z tomorrow. In the meantime, look for the low-level jet to increase during the next several hours, and will include LLWS in the upcoming 00Z TAF's as a result.
Upper low spreading bands of -SN into the CWA early this morning with distinct upslope/downslope/downstream convergence signatures on KUDX WSR-88D. Today and this evening, upper low moves little and weakens a bit. Overnight into Wednesday, upper low weakens and starts moving away.
Lingering snow will slowly end from west to east during the day Wednesday as the low pressure system moves ewd from the upper midwest into the Great Lakes.
Most of the rain will fall southeast of the I-71 corridor and then colder air will enter in Wednesday evening behind a cold front. We will remain in southerly low level flow through this afternoon ahead of a developing low pressure system that will begin to lift out of the lower Mississippi Valley late in the day. Slightly cooler highs are expected on Wednesday from the mid 50s to low 60s under more cloud cover and weak neutral temperature advection.
Location of primary rain band will be dependent on the exact track of the low and the aforementioned deformation zone. Latest NAM/GFS/SREF trend the low further west than the previous forecast, bringing the best rain chances almost directly over Pittsburgh and through the heart of the forecast area. The arrival of the low and associated cold front make Wednesday high temps a little more difficult, but they will remain above average.
highs will struggle to make it out of the lower to mid 40s with this trend continuing for the foreseeable future.
/For the 18z TAFs/ A cold front has moved through all TAF sites except Wichita Falls, and north-northwesterly winds are occurring across the area. Surface temperatures have increased quicker than previously forecast near and south of a weak surface cold front/wind shift that existed near a Wichita Falls to Ada line as of 1045 am. For today, a dry cold frontal passage will pass by from northwest to southeast. Low-level cold air advection will bring in even cooler (though seasonable) weather for tomorrow. Expect most locations to drop to at least freezing, with a hard freeze likely north of I-40.
Given the extensive cloud cover and the low overhead, diurnal warming will be stunted, but readings will still be well above climatological normal. Forecast concerns deal with a cutoff upper low expected to form in the desert southwest this weekend, and move slowly eastward. Forecast soundings show cold air aloft, which means we can rule out any chance of freezing rain or sleet. Surface temps will be in the low to mid 30s, which means there is a chance of rain or snow. Winds will be southerly, and then go calm overnight as the center of the low passes overhead, before switching to the northwest after midnight.
315 PM CST Tue Nov 29 2016 Near-vertically stacked potent low pressure system continues to slowly move southeast across southern Minnesota this afternoon with a series of strong vort lobes rotating around the main low. Some moderation in temperatures is likely into the weekend ahead of the next developing western trough. EC and GFS are in fairly good agreement in digging an upper trough over the western CONUS by 12Z Tuesday.
341 PM CST Tue Nov 29 2016 After a brief respite from the rain today, a cold front, which is just to our west, will cross the region tonight. In addition, clouds will be returning for parts of the area as main upper trough moves overhead.
Confidence continues to grow that this feature will exist, and if so, should be able to bring a briefly unstable environment along with an enhancement in the low level wind profile. Convection will break out over the Lower Mississippi Valley this afternoon, then spread into south central Kentucky this evening. Guidance max temps in the 60s look like a good bet, and min temp forecast is on the high end of guidance as some parts of south-central KY may be hard pressed to dip below 60 tonight. Latter half of the week looks quiet for the Ohio Valley, with zonal flow aloft, but low-level flow out of the W-NW as high pressure trying to build in from the west meets resistance from the weakening low over the Great Lakes.
Scattered light snow showers will continue in the higher elevations with more isolated activity in the central valleys of Colorado this afternoon. For the remainder of the day then, on again off again showery type precipitation for the higher terrain with some continuing accumulations possible though not as great as seen over the last few days.
Current model trends keep this out of AR, some additionally showers and isolated storms are possible this afternoon to evening until the upper low pressure trough and cold front push through the region.
Mid/upper level low pressure currently located over the northern plains and upper Midwest will gradually progress eastward today and tonight. The highs will range from the upper 40s to the mid 50s. Despite the cloud cover a slightly cooler air mass will be in place causing lows to reach the upper 20s to lower 30s.
1029 AM MST Tue Nov 29 2016 Large broad trough was covering most of the western 2/3rds of the country this morning. a large upper level low over the Great Lakes is forecast to lift northeast with broad northerly flow aloft transitioning northwesterly.
Surface temperatures have increased quicker than previously forecast near and south of a weak surface cold front/wind shift that existed near a Wichita Falls to Ada line as of 1045 am. For today, a dry cold frontal passage will pass by from northwest to southeast. Low-level cold air advection will bring in even cooler (though seasonable) weather for tomorrow. Expect most locations to drop to at least freezing, with a hard freeze likely north of I-40.
South of the front, temperatures in the lower/mid 80s with dewpoints in the upper 60s to lower 70s. After the cold front passage, cooler and drier air will prevail across the region. Cooler than normal temperatures expected for Wednesday night into the weekend.
At the surface, a cold front extending from northeast to central MO was sliding east, with temperatures rising into the upper 50s and lower 60s across much of our region. With clouds blanketing much of the region on Wednesday and with a cooler airmass in charge, have leaned cool against MOS for daytime maxes, preferring the MET MOS for STL metro and areas to the N and W, while going with a MOS blend elsewhere, with most staying in the 40s. TES Dry and cooler weather conditions are expected Wednesday night through the remainder of the work week as the slow moving upper level low moves eastward through the Great Lakes region.
We've had reports of freezing rain or drizzle (north of Wolf Point and in Wibaux) and this has prompted to keep current warnings/advisories going.
Warm front continues to lift north with lower 60s dewpoints beginning to push into northern MS. upper trough. This is spreading lift across the Lower Mississippi Valley. The associated cold front is pushing east into the Arklatex at this time. As the warm front lifts into North Mississippi and the cold front approaches from the west a surface wave develops over Western Mississippi early this evening and tracks NE across North Mississippi.
137 PM CST Tue Nov 29 2016 Latest surface analysis shows a low across the western Great Lakes with a trailing cold front extending through central Missouri through central Red River Valley. A stationary/warm front was situated generally south of I-20 across AL/MS. The airmass along and south of the warm front was quite juicy this afternoon with dewpoints well into the 60s. For tonight, the initial question is how quickly/how far north the warm front progresses. The upper trough axis will push across by early afternoon ushering in the "cooler" air.
In fact, several storms already have showed evidence of a mesoscyclone/rotation occurring in the low-mid levels /mainly across portions of central, north central and northeast LA into south central AR/ but no tornado confirmation so far. This cold front will usher in a drier airmass as dewpoints were noted to be in the 20s and 30s behind the front per 21Z metars. Models suggest the convection will exit the region tonight /after 30/03Z/ with perhaps only some lingering precip across the far southeast zones, as the cold front aids to stabilize the environment.
An area of low pressure will move across the area Wednesday with a cold frontal passage Wednesday night.
Southeast to south low level flow will continue to bring in a warm and rather humid airmass through Wednesday with mid/upper level ridging holding across the Florida peninsula. Lows tonight will remain well above normal in the 60s with temperatures on Wednesday will warm into the lower to mid 80s away from the coast, while close to the coast the winds shifting to a more southwest will keep readings mainly in the mid 70s to near 80. An upper level long wave trough is forecast to dive along the West Coast of the U.
The main feature is an upper level low which is located across Minnesota today. This will force the trough axis through the area and leave us under northwest flow aloft. Expect seasonably cool highs in the low to mid 40s.
129 PM EST Tue Nov 29 2016 A wave of low pressure will ride northward from the Tennessee valley and move through the state on Wednesday. Will not mention any accums since temps in the NW won't even get to/below freezing by Thurs morning.
Wednesday will be just a touch warmer with some modification of the polar airmass and also slightly drier with dewpoints falling to the lower to mid teens by afternoon. The ECMWF has come more in line with the GFS in closing off a mid level cyclone deep into Mexico by the early weekend.
904 AM PST Tue Nov 29 2016 Dry weather with locally breezy north wind returns this week as high pressure builds along the West Coast. Despite the winds, temperatures are running cooler across most of the area compared to 24 hours ago and generally range from the 20s and 30s in the mountains to the 40s to lower 50s elsewhere. Dry weather with temperatures close to average will be the general rule this week as high pressure dominates.
Some low/mid level moisture will likely remain trapped in the mountains as airmass stabilizes later tonight, so should see a continuation of scattered but light snow showers over the higher ridges later tonight into Wednesday. Along the Front Range, not quite sure whether an anticyclone will set up or if sufficient daytime heating and mostly sunny skies helps mix the west winds in. Overall, it will be less windy tomorrow and the return of sunshine will make it feel much warmer, despite slightly below normal temperatures.
Environment Canada radar networks and the US 88D radars show a very long fetch of moisture moving around the upper low along the warm conveyor belt from as far away as western Ontario.
At the same time, a cold front will move through the area. A cold front will move through during the evening and overnight hours as well. Could easily see several spots fall to below freezing again tonight.
122 PM EST Tue Nov 29 2016 A wave of low pressure will ride northward from the Tennessee valley and move through the state on Wednesday. Will not mention any accums since temps in the NW won't even get to/below freezing by Thurs morning.
Dry conditions will then rule through the first half of the weekend with high pressure gradually building in.
A big upper level low centered over the eastern Dakotas will slowly shift off to the east over the next couple of days. As sfc cold front still off to our west will finally move through the cwfa today shifting ssw winds to the west. The lower levels have already dried out quite a bit, so other than some extensive mid/high level clouds early today, the frontal passage will be fairly benign. Cloud cover circulating around the upper low will affect the northern cwfa more versus the south. A ridge of high pressure is then expected to build in for Thu with more abundant sunshine. The general model forecast guidance has been consistent in digging a strong upper low into northern Mexico by Sat.
As this occurs, cooler air will wrap around the low with surface winds shifting from mainly out of the south today to out of the north on Wednesday. As the low traverses east across central Minnesota tonight into Wednesday, there will be a broad area with a chance for rain/snow showers.
Furthermore, a warm front is slowing lifting north from central Louisiana and thus had to increased dewpoints a bit across southeast zones as the previous forecast package was slightly slower in regards to low level moisture translation. Cannot rule out convection at ELD/SHV as well, but the remaining sites should remain dry as a cold front arrives later this evening into the overnight hours. The upper level low to the west will push a cold front through later today with a warm front moving northeast ahead of the front. The low level moisture along with warmer temperatures could allow east texas and central Louisiana areas to see severe weather later today, mainly hail and wind. The next weather maker will be another trough of low pressure out of the Pacific northwest that will move into southwestern US.