Aikyam-Lab/Synoptic-Bench huggingface dataset:
The south-southwest gradient will increase during the overnight and through Wed morning as high pressure advances to the mid Atlantic. Otherwise, the high pressure system and dry ambient airmass will sustain tranquil aviation conditions through Wed morning. Very cold airmass aloft as this mornings sounding indicate freezing level around 6kft combined with strong diurnal heating is yielding capes upwards to around 1k joules producing scattered showers mainly from the Thumb and Saginaw Valley on north. Showers and Thunderstorms will develop over Wisconsin and spread east-southeast along a strengthening warm front that will be lifting north through lower Michigan tomorrow afternoon.
This pattern shift will allow for much warmer temps to occur over the entire region this afternoon, and expect high temps to reach well into the 90s across most of the plains. With the zonal flow at midlvls, a lee trough will develop and expect breezy southwesterly dry winds to occur over the mtns roughly the western 1/2 of the plains.
254 PM EDT Tue Jun 27 2017 High pressure crosses tonight. Warmer, more humid and unsettled latter half of the week.
High pressure at the surface will continue to gradually shift east of the forecast area tonight into Wednesday. This will result in surface flow becoming more southeasterly through the period, thus resulting in slightly warmer conditions during the period. This increase in rain chances will come as a result of an upper trough shifting east out of Texas, and along the north central gulf coast.
Most CAM's are developing widely scattered storms along this trough and then quickly moving them eastward and out of our eastern counties mid/late afternoon. A second area of convection will most likely form over the higher terrain in a deeply mixed, warm and dry BL.
/Tonight through Wednesday/ The primary concern through the period will be convective trends into Wednesday as an MCS is expected to develop across the High Plains and reach Iowa during the early morning hours Wednesday. 35-50kts of inflow per 300-305K isent surfaces will support the MCS in some form into the night however, likely based on shallow convergence and outflow with some suggestions that the synoptic warm front will try to surge to northern Iowa or farther north. One interesting note is that the convection allowing model ARW cores are less aggressive than one might expect per the aforementioned shear and instability based on updraft helicity vs NMM cores, which are often on the higher end anyways.
Upper air analysis last evening showed a trough from the Great Lakes to east Texas with west to west-northwesterly flow over us. The subtropical ridge will begin to build back over Texas from the west.
255 PM EDT Tue Jun 27 2017 A weak upper level system will cross the area by this evening, but no precipitation is expected and dry and cooler weather will continue through Wednesday.
Through the rest of the day, the ridge aloft will build westward some, with flow becoming southwest while low-level flow will become more southeasterly, but still rather light.
106 PM EDT Tue Jun 27 2017 A trough of low pressure will remain to our west through mid week. Weather disturbances moving out of the trough will cross the area this afternoon and again on Wednesday.
A trough axis was objectively analyzed through northern AZ this afternoon and has depressed H5 heights by 3-4dm throughout the entire SW Conus per 12Z sounding data. However, the same sounding data showed thermal profiles through the H8-H7 layer have changed very little in the past 24 hours with weak CAA lagging the trough into central CA/NV.
251 PM CDT Tue Jun 27 2017 High pressure will continue to move off to the east as the upper level pattern becomes zonal. Dry weather is expected tonight through tomorrow morning, but with the high to the east, southerly winds will return to the area during the day Wed and bring warmer temps and higher dwpts into the area for the rest of the week. As this first complex of storms redevelops and moves into the Great Lakes region, the associated cold front/outflow boundary will begin to lay out over parts of central IL, resulting in storm possibilities continuing and increasing Wed night. with the highest pops being in the north part of the CWA.
High pressure will continue to build over the area on Wednesday and slide off the coast by the weekend. Lows tonight will fall to the low to mid 60s with highs Wednesday in the mid to upper 80s.
604 PM EDT Tue Jun 27 2017 A cold front will pass through early this evening with high pressure building east from the OhiO Valley. The high passes south of the area Wednesday afternoon and night.
Cool afternoon highs in the lower-mid 60s from around metro Orlando and Cape canaveral northward. Highs climbing a bit warmer in the south where there may be a few cloud breaks. (previous) Low pressure developing to the north of the Bahamas will shift into the open Atlantic as high pressure settles across the southeast.
Highs from the lower to lower 50s across the region were good for now. Southwesterly flow aloft may bring in some slightly warmer air in by the afternoon, mixed with sunshine and southern zones may reach the mid 50s.
1007 AM EST Fri Dec 29 2017 Longwave trough over much of N America into the Deep South easily seen in water vapor imagery and upper air plots. Surface frontal boundary stalled over the C FL Peninsula and E Gulf with cooler airmass N of the front and not a cool south.
Chattanooga Airport, TN 46 29 45 22 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 41 28 41 18 / 0 0 10 10 Oak Ridge, TN 40 27 41 18 / 0 0 10 0 Tri Cities Airport, TN 39 23 37 15 / 0 10 10 10.
631 AM EST Fri Dec 29 2017 Aviation One area of low pressure was tracking through the region early this morning leading to snow.
Dry and mild temperatures continue today as upper level ridging continues to dominate. A weakening cold front now appears like it will stall out and fall apart over far Northern California. Have removed a slight chance of precipitation for northern Shasta County, with just an increase in cloud cover expected and slightly cooler temperatures.
Coastal trough continues just east of the Middle Texas coast late tonight. Some differences between models on the evolution of this low, but all generally agree to lift it northeast of the area by mid-day Saturday. While still below normal, temperatures will warm a bit today, into the lower to mid 50s. On Saturday, much warmer 850 temps and thinning cloud cover should allow temps into the 60s to even around 70 in the southeast. Low tonight from the mid 40s west to the lower 50s east.
Craig-Casper gradients along with H7 progs of 60-70 knots continue to support high confidence that this high wind event will continue thru much of the day. The first was to extend the High Wind Warning through mid-afternoon Saturday at Arlington. The second was to cancel the High Wind Watch for the southeast Wyoming plains. The arctic air mass will remain in areas north of the Pine Ridge in the northern Panhandle, where Chadron will only barely reach the teens for highs.
Those who don't like winter will find today the most tolerable day of the coming week, with highs topping out just either side of freezing and light winds. Upper trofiness will continue over the eastern CONUS for most if not all of the first week of 2018.
Early on this will help spread warmer air at low-levels into southwest NEB.
422 AM MST Fri Dec 29 2017 Upper level analysis has broad trof across the eastern CONUS and weak ridging across the west. Cold air is shallow today, so temperatures in the higher Black Hills could warm into the lower 20s. Snow will taper off and end Saturday night as arctic high pressure pushes into the Northern Plains.
As a result, some cloudiness across the eastern counties, and full insolation in the west while tapping into higher terrain warmer and drier source air, may result in quite a contrast in highs this afternoon, relegating highs to just above freezing near Pratt while soaring into the 60s near Elkhart. In advance of the stratus, some freezing fog may develop as well especially across the 281 corridor where the dew point depressions are lowest this morning.
The afternoon forecast will focus on the threat for possibility for patchy freezing drizzle across the south late tonight. /issued 449 AM CST Fri Dec 29 2017/ Moderating temps and light winds to prevail across the Midsouth today, as a 1033 mb Arctic high pressure ridge settles in. The first Arctic cold front will arrive Saturday, though cold temps will lag a bit and arrive to the Midsouth late Saturday night.
605 AM EST Fri Dec 29 2017 Low pressure off the Southeast Coast will move farther offshore today. Canadian high pressure in the forecast area will be reinforced behind a dry cold front Saturday night. The forecast is on track with just a minimal chance of freezing drizzle in the extreme southeast section. Shallow moisture has spread inland associated with low pressure off the Southeast Coast. Dry high pressure will ridge into the area from the north today and tonight with low pressure farther off the Southeast Coast. We leaned toward the lower temperature guidance because of the cold air mass. The models show little moisture associated with a reinforcing cold front approaching Saturday and moving into the area Saturday night.
617 AM EST Fri Dec 29 2017 Low pressure will move southeast across the Great Lakes today through Saturday.
The cold air appears to be really shallow as it gets farther west, so we may not see much in the way of clouds over the I-25 corridor region, but it will become noticeably cooler. It will be cold and all of the plains will remain below freezing with low clouds and flurries.
Upper air analysis last evening showed a trough extending from western Kansas to the Baja Peninsula with westerly to northwesterly flow over Texas. The surface flow will remain weak with high pressure over the region. A cold front will drop through north Texas Saturday and reach our northern border by the end of this period.
319 AM MST Fri Dec 29 2017 Main concern for today will revolve around the High Wind Warning for the Front Range Mountains and Foothills. Expect south to southeast winds to occur east of the trough today. Much cooler readings east of Sterling where high temperatures will struggle to reach 40. For tonight, although strong winds are expected to persist above timberline the wave amplification will not be as pronounced so stronger gusts should be more localized and confined to the higher mountains. A sharp temperature gradient will occur with 50s in the lower foothills to 30s to near by low lying areas just off to the east.
Clear skies were 75-100 miles off to the northwest of the Altamaha River, and skies will begin to clear out from north to south this afternoon as high pressure builds into the region. Highs today will be 10-15 degrees below normal, with temperatures near 50 to the low 50s, except the mid to upper 50s across north central Florida.
553 AM CST Fri Dec 29 2017 Freezing drizzle is expected to develop later today into tonight, impacting much of the forecast area. Temperatures north of the MO River will solidly be below the freezing mark at the surface, with widespread teens and 20s expected. South of the river, warmer temps look to reside here with highs hovering right around the freezing mark. Despite the widespread sub-freezing temps expected today, the cause for the freezing drizzle is due to the combination of a low-level saturated layer that will reside outside of the favorable dendritic growth zone, inhibiting ice crystal formation for precip to fall as snow rather than the freezing drizzle expected.
217 AM PST Fri Dec 29 2017 Sunny and warmer today then cooler for the weekend.
/issued 449 AM CST Fri Dec 29 2017/ Moderating temps and light winds to prevail across the Midsouth today, as a 1033 mb Arctic high pressure ridge settles in. The first Arctic cold front will arrive Saturday, though cold temps will lag a bit and arrive to the Midsouth late Saturday night.
High clouds over the area are once again keeping temperatures similar to or slightly warmer than those from this time yesterday with current readings generally in the 30s to upper 40s. The ridge axis of the strong dome of high pressure will begin to shift over California today with today's high temps expected to be the warmest of the week. The high pressure ridge is forecast to weaken and begin to edge eastward during the weekend with a gradual cooling trend.
Moisture continues to move up and spill over an upper ridge over the region. mainly in the form of freezing rain over the northern CWA in Washington from the Lower Columbia Basin northward through the Yakima and Kittitas Valleys and the Washington Cascade east slopes. A winter storm warning for mixed precipitation and significant ice accumulations with freezing rain remains in effect in these areas. Will leave these warning in place for now but may need to cancel them as temperatures are rising in the valleys which may turn all the freezing rain to rain early. An upper trough will flatten the ridge and then move down the east side of the ridge as a back door cold front with colder air and lowering snow levels tonight and Saturday. Winds will be locally breezy on the ridge tops.
1030 AM EST Fri Dec 29 2017 Arctic high pressure will gradually weaken over the Carolinas through Saturday.
for snow remains on track as we still expect the higher snowfall amounts/rates in the far southwest where the above mentioned forcing mechanisms best line up. Snow will be on the decrease from north to south today as forcing diminishes and drier air associated with Arctic high pressure moves into the region. Understandably surrounding offices due to the high confidence of our forecast felt headlines were needed past 00Z.
Additional flight restrictions may enter the region early Saturday morning following a cold frontal passage.
A southerly flow aloft continues to pour over the region, bringing a continued threat of freezing rain across valleys where cold-pooling has stayed in place. This means that the lower Treasure Valley near Ontario, the Weiser Basin and to the northwest towards Baker City, look to remain under the treat of freezing rain through the late morning when surface temperatures warm (generally below 5000 feet). Have kept the Winter Weather Advisory going for snow in the West Central and Boise Mountains, and for the threat of freezing rain in the Weiser Basin and Baker County. Saturday remains a difficult forecast as a cold front passes quickly through the region. Current thinking is that cold-air will continue to pool in low-lying valleys such as the Weiser Basin and the Lower Treasure Valley (including Ontario), bringing another threat of freezing rain to these areas.
This system has the potential for 1 to 3 inches through Saturday morning, with the highest totals expected along and north of the I-70 corridor. Highly amplified mid and upper level flow with a strong ridge over the west coast and a trof over the east. These snow showers are expected to diminish in the afternoon as arctic high pressure begins to nose into the region. Lows tonight from the lower teens north to the lower 20s southeast. An upper trough featuring much below normal geopotential heights will continue to dictate ILN weather through the period.
1023 AM EST Fri Dec 29 2017 Update One area of low pressure was tracking through the region early this morning leading to snow.
A reinforcing shot of arctic air will arrive on Saturday and a large upper trough will keep the flow of dangerously cold air coming through the entire forecast period.
427 AM MST Fri Dec 29 2017 Upper level analysis has broad trof across the eastern CONUS and weak ridging across the west. Cold air is shallow today, so temperatures in the higher Black Hills could warm into the lower 20s. Snow will taper off and end Saturday night as arctic high pressure pushes into the Northern Plains.
The cold front reaches the coast this evening, bringing gusty conditions to the coast and just inland.
High pressure and a west to northwest upper flow will dominate through the period. Another cold front will affect north and central GA just beyond the end of this forecast time frame.
Locations along and south of Interstate 44 will approach 40 with locations across Central Missouri only making it into the low 30s. With temps around freezing, do think that some freezing drizzle may be possible with better chances just northeast of the area toward Jeff City. With a cold ground, even just a little freezing drizzle can cause some impacts.
At this time, near-term sky cover and resulting temp trends will be the biggest forecast challenge, as it is not clear at this time of the accuracy of the high resolution models, though some breakup has been recently seen on GOES-E from the northwest and south. After highs mostly above freezing today, highs on New Year's Day are expected to range from the mid teens to the lower 20s. Arctic high pressure will continue to sink south through the first half of the week, remaining centered northwest to west of the PAH forecast area.
230 AM PST Fri Dec 29 2017 A persistent ridge of high pressure along the West Coast will provide quiet and dry weather through New Years Day, with well above average daytime temperatures and relatively light valley winds. High pressure remains over CA/NV through the weekend, with mild afternoon temperatures (10 to 15 degrees above normal). This wave will increase the winds aloft over northern CA/NV starting today, with ridge winds increasing to around 60 mph. Farther out in the Basin and Range, highs are expected to have trouble getting out of the low to mid 50s with mixing later and less effective than closer to the Sierra.
Low level moisture has increased with the westward surge and brought dewpoints into the lower to mid 30s into the central Permian Basin. There is still dense fog, but think temperatures will remain above freezing so have changed the Freezing Fog Advisory to a Dense Fog Advisory in Martin, Midland, Ector, Crane and Upton counties. Freezing fog is being reported at several observation sites farther north and west, and we still expect conditions to deteriorate into Eddy County in New Mexico, so will leave the Freezing Fog Advisory in affect until 29/16Z.
At this point the heaviest snow will occur between the highway 30 and highway 20 corridors and between Fort Dodge and Estherville.
potential for freezing drizzle, and bitter cold temperatures/wind chills. Stratus on satellite imagery is streaming northward along with warmer temperatures. Forecast soundings show moistening of the low levels, some of this warm air making it into southeast Nebraska. Temperatures guidance is a bit all over the place; some in the upper 20s to lower 30s, however for now left highs in the lower to mid 20s. with the lack of ice, there is a potential for some light freezing drizzle/patchy fog this afternoon. Highs today should vary from the lower teens to the mid 20s. Due to winter weather advisories posted for parts of FSD/DMXs area and freezing drizzle possible over parts of our southeast Neb. Brought the light snow farther south from trace to 2 inches with the lighter amounts toward I80 and the higher amounts toward Sioux City.
High pressure aloft along the west coast will maintain a generally dry and mild westerly flow aloft across much of Utah today. A dry and mild west-northwest flow aloft continues across the forecast area this morning, downstream from a low amplitude mid level ridge centered along the Pacific Coast. Shallow valley inversions remain in place across the lower elevations of northern Utah, however these stagnant cold pools are relatively weak and have been modifying over the past couple of days as temperatures aloft continue to warm, and this should once again be the case today.
1019 AM EST Fri Dec 29 2017 Low pressure will track off the Carolina coast this morning.
Another quick shot of 1 to 2 inches of snow is thought possible south of a line from Mobridge to Miller. Then, the low level caa kicks in tonight and temperatures start their tumble into the below zero "for highs and lows" for the weekend.
Above-normal temperatures will persist for one more day then a weak cold front will move through northern Nevada on Saturday.
High pressure aloft along the west coast will maintain a generally dry and mild westerly flow aloft across much of Utah today.
513 AM CST Fri Dec 29 2017 For this morning, have allowed the Freezing Fog Advisory to continue at this time and have also expanded it to include Deaf Smith county based on current observations. The freezing fog and attendant low clouds should erode later this morning. Warmest max temps should occur in far western sections, with the lowest in the far eastern zones. The leading cold front will move across the OK and TX Panhandles tonight, with sharply colder temperatures anticipated for Saturday. Have retained patchy freezing drizzle across ern third of the area tonight and about the ern half of the fcst area Saturday monring in the post frontal airmass.
Also concerned about some patchy dense fog and potentially some freezing fog for a few hours after sunrise until temps can warm above freezing. Enjoy today, as this looks to be the last time most locations will be above the freezing mark until Thu or Fri! Temps will begin their plunge into the deep freeze starting this evening and overnight, as a strong arctic cold front charges south across the region during the late evening hours. The cold front tonight, will lead to a significant arctic outbreak for the rest of the weekend into the New Year, as some of the coldest air of the season moves across the area as a strong arctic high pressure system builds south across the region.
503 AM EST Fri Dec 29 2017 Arctic high pressure will build toward the region today through Saturday.
A cold front will stall over south central Florida this afternoon.
849 AM EST Fri Dec 29 2017 Arctic high pressure will build toward the region today through Saturday.
Did I mention that it will be cold? A weak ridge today slides east with a dry cold front in store for tomorrow.
646 AM EST Fri Dec 29 2017 Arctic high pressure remains over the area today.
917 AM EST Fri Dec 29 2017 Low pressure off the Southeast Coast will move farther offshore today. Canadian high pressure in the forecast area will be reinforced behind a dry cold front Saturday night. Dry high pressure will ridge into the area from the north with low pressure farther off the Southeast Coast through tonight. We leaned toward the lower temperature guidance because of the cold air mass. The models show little moisture associated with a reinforcing cold front approaching Saturday and moving into the area Saturday night.
608 AM EST Fri Dec 29 2017 Low pressure off the Southeast Coast will move farther offshore today. Canadian high pressure in the forecast area will be reinforced behind a dry cold front Saturday night. Shallow moisture has spread inland associated with low pressure off the Southeast Coast. Dry high pressure will ridge into the area from the north with low pressure farther off the Southeast Coast. We leaned toward the lower temperature guidance because of the cold air mass. The models show little moisture associated with a reinforcing cold front approaching Saturday and moving into the area Saturday night.
449 AM CST Fri Dec 29 2017 Moderating temps and light winds to prevail across the Midsouth today, as a 1033 mb Arctic high pressure ridge settles in. The first Arctic cold front will arrive Saturday, though cold temps will lag a bit and arrive to the Midsouth late Saturday night.
With veering sfc winds this afternoon parts of NE OK may see a period of VFR conditions late this afternoon, however the forecast has trended more pessimistic given the low potential for daytime mixing. With a period of light winds ahead of strong cold front, there may be some locally dense fog across NE OK before the front arrives 06-12z and brings shift to north winds.