Aikyam-Lab/Synoptic-Bench huggingface dataset:
Stubborn high pressure will remain over the region for the next several days keeping the weather dry. These clouds are in association with a s/wv trough riding down the front side of an EPAC ridge. Highs in the lower 60s are forecast across the San Joaquin Valley, around 10 degrees above normal for late December. Dry conditions will continue through the rest of the week as the upper ridge of high pressure strengthens over California. The 00Z ECMWF suggests it could very well be wet on New Year's Day as it digs an upper low down from the Gulf of Alaska to the California coast. Also, the GFS tracks this low well north of the region and keeps us high and dry.
High pressure strengthens through midweek with a slight warming trend and ongoing dry conditions. Thus, temperatures will warm into the upper 50s across the northern portion of the region to the lower 70s across the Central Coast. High pressure off of the California coast is forecast to build through late week and result in a slight warming trend. The ECMWF has shifted to show high pressure breaking down as a deepening mid/upper level trough approaches the West Coast.
Wednesday is expected to be a little warmer, but how much warmer is a valid question.
The broad, cold mean trough remains in place through the central CONUS with minor impulses continuing to track along the southern PV gradient north of the polar jet. Arctic air is well entrenched into IA as well with the front now well to our south and high pressure oozing southeast through the Dakotas and MO Valley. Have nudged lows down a bit further toward the lower half of guidance but these may not even be enough considering upstream obs, snow cover and expected light winds.
A high pressure ridge is bringing dry and stable conditions to the area this morning. East of the Cascades areas of freezing fog have developed in the Klamath Basin, including at Klamath Falls. So there remains a slight chance for light precipitation to fall as freezing rain for northern Klamath county late Wednesday morning, mainly from Modoc Point north to near Chemult. Overall the risk is slight as models show temperatures hovering near or just above freezing then gradually warming as the light precipitation moves into the area. Weak ridging builds into the area behind this system on Wednesday night.
401 AM CST Tue Dec 26 2017 Early morning surface analysis shows cold front nosing into northeast/central Oklahoma extending from Watonga to near Tulsa.
The other problem this morning will be the low chance for flurries and/or fog, but its believed chances are low to have any visibility restrictions at this time. For today, latest cold front is pushing southward across the fcst area.
/issued 427 AM CST Tue Dec 26 2017/ The primary forecast issues are freezing drizzle today and the cold front timing for the upcoming weekend. For today, freezing drizzle is expected to develop across southwest Oklahoma/western north Texas later this morning. A Winter Weather Advisory was issued to account for the upcoming freezing drizzle event. Some locations within the advisory area may initially above freezing; however, by this evening, any locations that are above freezing in western north Texas should fall below freezing. The most likely areas to initially be above freezing during onset would be eastern/southern parts of Clay and Archer counties.
This southwest flow aloft is carrying moisture above the coastal trough and over the cool dome, and the result is some light over-riding rain and drizzle.
Strong Hudson Bay low keeping broad trough over North America and pulling very cold arctic air southward into the northern plains today. By midweek, the Hudson Bay low begins to weaken and the upper trof flattens somewhat. Canadian high pressure currently over northeast Montana will remain over the area today through most of Tuesday.
502 AM CST Tue Dec 26 2017 A layer of mid to upper level clouds are keeping temperatures near the freezing mark this morning across the Midsouth. leading to a sunny day with temperatures a good bit warmer than yesterday, in the upper 30s to low 40s. Given the strength of the warm nose, expecting precipitation type to be either rain or freezing rain, depending on exact surface temps. It's shaping up to be quite cold tomorrow behind the front, with temperatures struggling to get above freezing despite sunny skies.
Patchy freezing fog has been reported near CTB and HVR, so have added this to the late morning forecast for the North-central plains. Snow has diminished across the area though there may be a few flurries and patchy freezing fog that may briefly reduce conditions to MVFR. Freezing fog will not be widespread as mid and low-level clouds persist.
945 AM EST Tue Dec 26 2017 Quiet WX pattern in play as an H100-H70 anticyclone centered over the GOMex/central FL keeps the region under a dry, surpressed airmass while blocking a stationary front over the FL Keys/Nrn Bahamas from drifting north. Ridge axis centered over the GOMex extending acrs the S FL Peninsula will generate a steady E/NE breeze over the lcl Atlc.
The freezing level is near 12,300 feet, with the -20C level near 23,000 feet.
Some snow showers will continue today over the higher mtns with lingering flurries this morning over far se Wy into the Panhandle.
Freezing spray is expected toward the open waters.
A weak, roughly east-to-west-oriented deep layer ridge is south of this cyclonic flow regime, extending over the Florida Keys and adjacent coastal waters. Deep ridging has prevailed over the Florida Keys for the better part of two weeks. In fact, the once strong subsidence inversion layer in the lower troposphere has gradually weakened during the last few days, and sufficient potential buoyancy for shallow convection has developed over the warm Florida Current/Gulf Stream waters just upstream of the Keys. The rapidly weakening cold front analyzed over central Florida 24 hours ago has nearly frontolyzed while becoming stationary just north of the service area. Currently, air temperatures in most Keys island communities are in the lower 70s, with dewpoint temperatures remaining in the upper 60s.
Beneath this high, very dry air and lighter winds are allowing temperatures to fall well below zero.
Wind chill headlines remain in place as center of 1045mb high pressure remains across eastern Montana with a ridge axis extending southeast into South Dakota/Nebraska. With this high overhead, and no high clouds evident, anticipate temperatures will again rocket down into the teens and 20s below zero tonight - though the low temperature forecast is again tempered by the lack of a complete snow cover. As the high begins to move off, we see a buckling of the cold air back to the east in return flow.
An upper level high pressure ridge over the west coast will bring dry conditions through the short term forecast period.
The large Arctic upper low is centered over Hudson Bay this morning which has established a broad trough over most of CONUS, except for the far West. Templer Previous discussion: Strong Hudson Bay low keeping broad trough over North America and pulling very cold arctic air southward into the northern plains today. By midweek, the Hudson Bay low begins to weaken and the upper trof flattens somewhat. Canadian high pressure currently over northeast Montana will remain over the area today through most of Tuesday.
An upper ridge will bring mostly dry weather today.
Temperatures will remain quite cold for the rest of the week, which could contribute to a freezing spray risk near open waters.
A cold front will then move through the region this evening with winds increasing out of the north, with gusts of 20-25 KTs possible. This is all in response from a developing coastal trough leading to moderate upglide in the 295K-300K isentropic levels. This is expected to continue through the morning hours before the trough lifts farther north slowly tapering off rain chances through the afternoon. Moderate to strong northeast winds are expected to develop in wake of a cold front.
Thus, sfc temps wl be the determining factor if any freezing rain is observed. We are not for any travel problems, as sfc temps are only expected to be sub-freezing for a very short time before rain tapers off early Wed morning.
Broad upper level trough was located over central Canada and the Northern Plains. Water vapor loop indicated an upper level trough over southern SASK will move southeast over the area today. Ridge will move over the forecast area tonight. Upper level trough over the Yukon will rotate into southwest Canada by 12Z Wed. Downstream ridge will approach the area Wed morning.
After some cirrus slides east out of the Lower Susq, additional cirrus will work from the west today. Winter Weather Advisory for those counties will continue through 6 PM Wednesday, with the highest accums occuring today into this eve over NW Warren Co.
The only changes needed for the predawn update were downward adjustments to hourly trends as a reinforcing cold front is sagging over the region this morning.
This is all in response from a developing coastal trough leading to moderate upglide in the 295K-300K isentropic levels. This is expected to continue through the morning hours before the trough lifts farther north slowly tapering off rain chances through the afternoon. Moderate to strong northeast winds are expected to develop in wake of a cold front.
High pressure over the Mid-Atlantic states ridges down across Fl and the Gulf of Mexico as a weak inverted trough tracks west through the state. High pressure dominates with northeast or east winds that back to north or northeast as an inverted trough slips across FL this afternoon.
335 AM MST Tue Dec 26 2017 Current surface analysis shows arctic front well south and west of the forecast area, with high pressure centered over far eastern MT. Upper level analysis continues to show low over western Ontario, with broad trough covering much of Canada and the US.
427 AM CST Tue Dec 26 2017 The primary forecast issues are freezing drizzle today and the cold front timing for the upcoming weekend. For today, freezing drizzle is expected to develop across southwest Oklahoma/western north Texas later this morning. A Winter Weather Advisory was issued to account for the upcoming freezing drizzle event. Some locations within the advisory area may initially above freezing; however, by this evening, any locations that are above freezing in western north Texas should fall below freezing. The most likely areas to initially be above freezing during onset would be eastern/southern parts of Clay and Archer counties.
512 AM CST Tue Dec 26 2017 Cold front has pushed through the area and we are looking for a protracted period of MVFR clouds across the region. /issued 415 AM CST Tue Dec 26 2017/ Upper level long wave trough remains established across much of the CONUS as a large amplitude ridge builds just off the West Coast.
415 AM CST Tue Dec 26 2017 Upper level long wave trough remains established across much of the CONUS as a large amplitude ridge builds just off the West Coast.
Midlevel clouds are expected to increase again late tonight as a weak trough approaches, but with no aviation impacts.
454 AM MST Tue Dec 26 2017 12Z TAF CYCLE Impacts today will focus over eastern NM where IFR cigs developed behind a cold front stretching from KCAO to KTCC and KCVS. Colder temperatures reach further south to Roswell Wednesday with some potential for areas of freezing drizzle Wednesday morning in eastern New Mexico.
Gusty winds are expected across NE OK/NW AR this afternoon/evening as arctic high pressure builds into the region. /Issued 401 AM CST Tue Dec 26 2017/ Early morning surface analysis shows cold front nosing into northeast/central Oklahoma extending from Watonga to near Tulsa.
Cannot rule out a sprinkle or light shower along coastal areas as moisture convergence increases due to a coastal trough, but chances are very low.
SHORT TERM (Today through Wednesday): A coastal trough is located just east of Padre Island early this morning. Brownsville radar currently indicates some light rain and drizzle across portions of the lower Texas Gulf waters. Latest surface analysis shows high pressure centered over the middle Tennessee valley. The coastal trough is expected to weaken this morning as high pressure continues to move further east and a warm front moves north across the eastern portions of deep south Texas today. High temperatures today are expected to range from the mid to upper 60s across the west to the lower 70s across the east. Another surge of high pressure arrives late tonight into Wednesday morning. The associated cold front is expected to move through the northern Ranchlands after midnight and after daybreak in the Rio Grande Valley.
419 AM CST Tue Dec 26 2017 Our next cold front is set to move through the region today, entering northern areas later this morning. High temperatures east of the Pecos River look to be 10 to 15 degrees cooler than yesterday. Later this afternoon and evening, low clouds will develop from east to west as warm, moist air begins to move over the much cooler airmass. The main concern is the potential for freezing drizzle to impact areas mainly near and east of the Pecos River late Tuesday night through Wednesday morning, where temperatures fall below freezing. Still not expecting much accumulation, however some light icing on bridges and elevated surface may create problems for the morning commute.
Northeast winds between 5-10 knots generally prevail today, increasing slightly tonight as a reinforcing cold front moves across the region. A mainly zonal mid level flow pattern will persist across the central Gulf Coast region today and tonight along the base of a broad upper level trough encompassing much of the eastern CONUS.
As such it is evident that moistening in the low-mid levels have been taking place, as this overrunning scenario is starting to show light radar echoes across deep east TX and central LA. Late tonight/early tomorrow morning, as subfreezing temps occur around the I-30 and Highway 82 corridors, progged model soundings is indicative of the potential for the light rain transitioning to light freezing rain /notable warm nose in the mid-levels with subfreezing temps at the sfc/. Although little to no ice accumulations are expected, overpasses and bridges could have a few slick spots so caution should be exercised.
For today, latest cold front is pushing southward across the fcst area.
As of 09Z Tuesday morning, the stubborn ridge/trough mid-level pattern continues across the CONUS. At the surface a stout anticyclone continues to intrude on the central Plains with reinforcing CAA.
518 AM EST Tue Dec 26 2017 A cold front will cross the region today.
A weak upper ridge pattern will amplify toward the weekend which will allow mainly dry and mild weather to continue across Nevada for the remainder of 2017.
/issued 502 AM CST Tue Dec 26 2017/ A layer of mid to upper level clouds are keeping temperatures near the freezing mark this morning across the Midsouth. leading to a sunny day with temperatures a good bit warmer than yesterday, in the upper 30s to low 40s. Given the strength of the warm nose, expecting precipitation type to be either rain or freezing rain, depending on exact surface temps. It's shaping up to be quite cold tomorrow behind the front, with temperatures struggling to get above freezing despite sunny skies.
614 AM EST Tue Dec 26 2017 A trough of low pressure will drop south through the region today and tonight.
Cold air and upper troughing remain over the area this forecast period with lake effect snow continuing as well. In the extended, GFS and ECMWF show a broad 500 mb trough with cold air over the central U. The arrival of the arctic air mass will also result in periods of heavy freezing spray late tonight into mid week. Heavy Freezing Spray Warning until 7 AM EST Wednesday for LSZ249>251-266-267. Heavy Freezing Spray Warning until 7 PM EST /6 PM CST/ this evening for LSZ241>245-248-263>265.
Other convection was over southwest Missouri north of a warm front. Dewpoints south of this front in the lower 70s with southerly flow over it. Upper trough swings into the area late tonight, which should bring cyclogenesis well to the east for convection to end by early Sunday morning.
This boundary will move northward Sunday morning as a warm front. Low pressure will track near or just north of Lake Erie Sunday night with a cold front crossing the region.
There will be additional shower and storm chances drng the aftn as a cold front approaches late in the day. cooler at the lake.
239 PM EDT Sat May 27 2017 Ridging over the region will weaken on Sunday as a frontal boundary slowly slides into the area. Upper level ridge will begin flattening as trough moves into the central US.
316 PM EDT Sat May 27 2017 High pressure will slide south of the region tonight. A cold front will move into the area Sunday and stall.
147 PM EDT Sat May 27 2017 A weak area of low pressure will move east through the Ohio Valley today while high pressure remains to the north over lower Ontario. Low pressure over the central plains will then move northeast extending a warm front over the area Saturday night before moving over the area on Sunday.
Drier and more subsident conditions are expected on Sunday as a little more ridging moves in from the west. Lingering moisture over the mountains along with heating of the higher terrain will de-stabilize the airmass over the mountains with scattered afternoon thunderstorms expected. Afternoon showers should remain over the mountains, and then dissipate as they move away from the higher terrain. Temperatures should also be much warmer, into the lower 70s on the plains.
1227 PM CDT Sat May 27 2017 Only minor adjustments to keep up with some warmer temperatures in the northeast as the inversion mixes out rapidly with thinning clouds, and to POPs as the weak wave moves across our south/southeast counties while dissipating. If we can get showers to develop, NAM BUFKIT profiles show that bases will be above the freezing layer, so we could see some gustier winds with showers. Large scale lift out ahead of the approaching trough is bringing a large area of precipitation from far south central SD southward into KS.
301 PM EDT Sat May 27 2017 Persistent cumulus cloud lines have been anchored onto the lower and middle Florida Keys today, with a recent shower developing over central Big Pine Key. A mainland seabreeze has developed turning winds southerly across the middle and upper Keys, with a light northerly flow in part to a strong portion of the ridge maintaining itself across the eastern Gulf of Mexico.
This will in turn present strong surface convergence within a highly unstable environment, as MUCAPE values exceed 4000 J/kg along and south of the warm front. Any overhead impulses could trigger warm advection showers/storms, though a blocking ridge pattern should limit widespread precipitation chances.
Temps near 90, coupled with dewpoints in the lower to mid 70's have combined to result in heat indices around 100 degrees. Severe storms will be possible once again on Sunday afternoon through Sunday night, this time for a greater portion of our region, as a cold front nears the region, providing enough lift to finally break the cap. /3/ On Sunday night we will have an upper trough centered with a closed low over South Central Canada which will extend down to the Lower Mississippi Valley.
Also, a tornado risk will exist, if a storm can either develop in an area of backed/stronger surface winds, or with the extreme instability that exists, can locally enhance the low level helicity/shear. Elsewhere, storms may then try to develop south and west along an advancing cold front from Missouri southwest along the I-44 corridor. However, by late evening, the models do develop storms along the cold front across southern Oklahoma.
Will still have a chance of showers and storms on Sunday until an upper level trough centered over the northern Plains and a cold front shift east- southeast of our forecast area. GKS Cooler conditions can be expected Sunday night due to a clear sky and lower surface dew points.
146 PM EDT Sat May 27 2017 High pressure continues to keep the region mostly dry into the overnight hours tonight. For Sunday, a low pressure system and trailing cold front will move through the area with showers and storms.
325 PM CDT Sat May 27 2017 Upper rough rotating around upper low over Manitoba will move across eastern Nebraska and western Iowa tonight.
Upper air analysis this morning showed nearly zonal flow over TX with a trough over the central Rockies. At the surface, high pressure was centered over the Gulf making the winds across our CWA from the south to southeast. The upper trough will move away from the Rockies into the central plains and turn the flow over TX to the south-southwest.
For Sunday, scattered thunderstorms will be possible across much of West Central Texas as a cold front moves south across the area. Much cooler for Sunday with highs in the lower to mid 80s. Also, have likely Pops Sunday night across the southeast part of the area due to better large scale ascent and a cold front just south of the area.
322 PM CDT Sat May 27 2017 At H5 ridge over the western CONUS and closed low over south central Canada with trough into Great Basin. Upper trough will move through over night with clearing skies moving in from the west and precipitation ended. Have gone with cooler guidance with lows ranging from 40 to 50 west to east across the forecast area. Forecast area will remain under the influence of the upper low over southern Canada through mid week as it drifts slowly east into southwest Canada.
Continued snowmelt from the higher elevations will maintain elevated flows for small rivers and streams.
However, with the secondary trough moving through tonight, limited moisture and forcing associated with this system and have very low confidence with any measurable precipitation tonight.
240 PM EDT Sat May 27 2017 After a mostly dry overnight period, low pressure and a crossing front will bring rain chances Sunday and Sunday night. Any activity will fade this evening with the loss of heating, leading to a mostly quiet overnight period as midlevel ridging passes through. This will eventually push a cold front across the region Sunday night. Areas of SW PA into northern WV have the lowest FFG values at present.
High pressure will continue to build in over Arizona for Memorial Weekend with warmer temperatures, light winds and a slight chance for showers over the mountains of eastern AZ. There is concern for some pooling of smoke near the Snake Ridge fire as ventilation becomes poor tonight. We'll be watching the impacts of these winds on the Snake Ridge fire. On Memorial Day, high pressure aloft and light winds will bring a beautiful day for outdoor activities with warm temperatures at or a couple of degrees above normal. Some afternoon showers are possible over the higher elevation areas to the southeast with most of the area remaining dry. A weak trough of low pressure will brush northern Arizona with an isolated shower near the UT border this evening, and a shift of winds to the east and northeast on Sunday.
A ridge building over the region is keeping convection around the area limited to clouds, but some showers over the mountains are possible this afternoon.
An extremely unstable airmass over the region ahead of a cold front and dryline will set the stage for numerous severe thunderstorms over the region this TAF period. MVFR and possibly even IFR cigs will overspread the region behind the front, with a trend toward VFR on Sunday as cooler and drier air in the low levels moves into the region. The severe weather threat will continue into the overnight hours awaiting the passing cold front to clear the area from northwest to southeast.
The biggest change will probably be temperatures, which will be a little cooler by Sunday.