Aikyam-Lab/Synoptic-Bench huggingface dataset:
Temperatures remain above freezing in the lowest several thousand feet, so this suggests any light precipitation should remain rain. By the time cooler air arrives early Sunday morning, moisture and forcing is limited, keeping snow mostly out of the forecast. Temperatures will be close to seasonal, but a little cooler than today (Saturday).
650 PM EST Sat Nov 11 2017 Arctic high pressure will extend across the eastern United States through Sunday.
1051 PM EST Sat Nov 11 2017 Fair and cold conditions will prevail into Sunday as arctic high pressure overhead slides to the east.
Current temps range from the upper 40s Plateau, to the lower 50s southwest.
The cloud line as of 2 pm was just west of the Highway 63 corridor and progressing eastward. Highs will once again be on the cool side in the lower to middle 50s.
853 PM EST Sat Nov 11 2017 Dry Canadian high pressure over the eastern half of the country will move offshore tonight.
High pressure continues along the eastern seaboard.
Higher res models suggesting easterly upslope flow will help push stratus up the lower Arkansas River Valley through the evening hours, with areas of fog developing overnight. Warmer and Drier Across the Plains Today. The bulk of the low level moisture that has been entrenched over the lower Arkansas River Plains for the past few days has mostly moved east into Kansas today. On Sunday, a weak cold front will drop south through the plains and back up to the mountains during the afternoon. No precipitation and few clouds with the front, so mainly just cooler temperatures and southeasterly breezes across the plains Sunday afternoon.
413 PM MST Sat Nov 11 2017 Water vapor shows upper trof working through the Rockies into the Plains, with distinct short wave along the MT/WY border. Short wave/cold front will advance eastward across the region this evening with some associated light rain/snow showers, ending across our eastern zones around midnight. Very mild and dry air expected early this week with flat upper ridge overhead.
This low level moisture will continue to support low cloud cover through the overnight, and a slight chance of light showers or patchy drizzle exists as we move closer to dawn. The low clouds are expected to keep low temperatures warmer than last night, ranging from mainly the upper 40s to upper 50s across the area. Clouds will keep overnight temperatures considerably warmer than last night with lows in the upper 40s to upper 50s.
The trough will dissipate later this evening, with southeast flow returning to the region, drawing Gulf moisture back into the region.
A weak cold front will push through tonight, but the cloud cover should keep temperatures warmer than last night.
Expect dry and mild conditions under the influence of weak high pressure through the weekend.
but expect MVFR conditions to develop late tonight into the daytime hrs on Sun as a cold front drops south through the state.
Moisture will be confined to the low levels, but there may be just enough to produce some drizzle.
A strong ridge will hold across the southwest states. Note the low clouds already covering much of GA. The clouds and south winds will provide much milder temps than last night, Lows will be in the low to mid 40s.
718 PM EST Sat Nov 11 2017 Fair and cold conditions will prevail into Sunday as arctic high pressure overhead slides to the east.
Thick cloud cover and dewpoints near 0C will moderate temps overnight, but light snow or rain/snow mix is still possible in areas where temps approach freezing.
Overnight, a midlevel wave and some 700-500mb frontogenesis may bring some showers to the northern part of the forecast region, but should move out of the area well before temperatures reach freezing.
A cold front will continue to slide southeast through the area tonight, turning winds around to the north. High pressure at the surface will build east over the northern and central parts of the Plains on Sunday, reaching into IA and MN by late afternoon.
As usual at this time of year, middle level ridging, around 585-587 decameters ridging remains oriented from Mexico to across the Gulf of Mexico to across the Florida Peninsula to well east of the Bahamas. Overnight and Sunday, the strongest near 1035 mb arctic surface ridging will remain in place from Maine to New Jersey but cold air continues down to Georgia thru 12Z, with the ridge beginning to slide very slowly east into the NW Atlantic during Sunday.
An upper trough will produce rain and mountain snow at times through Sunday night.
The high clouds are pretty thick at this point, and the 5-10kft layer is beginning to moisten up over southeast Missouri. The system is forecast to sharpen as it approaches, inducing a surface trof which will move through the PAH forecast area during the day Sun. By then, the cold front's wind shift should be well underway. Some clouds may be a bit slow to clear in the east early Mon due to the departing trof axis.
Surface analysis this evening places a ridge of high pressure over the Mid-Atlantic/Southeast United States and extending back into the Lower Mississippi Valley. Infrared satellite trends indicate increasing clouds associated with an area of low pressure near the Texas/Oklahoma Panhandle. /issued 317 PM CST Sat Nov 11 2017/ Skies are mostly sunny across the forecast area this afternoon with temperatures ranging from the the lower 50s to mid 60s. A weak cold front will move across Oklahoma this evening and reach northwest Arkansas by Sunday morning. The cold front will move out of the region Sunday night with a small chance of rain over far eastern sections in the evening.
Warmer and Drier Across the Plains Today. The bulk of the low level moisture that has been entrenched over the lower Arkansas River Plains for the past few days has mostly moved east into Kansas today. On Sunday, a weak cold front will drop south through the plains and back up to the mountains during the afternoon. No precipitation and few clouds with the front, so mainly just cooler temperatures and southeasterly breezes across the plains Sunday afternoon.
Dewpoints are expected to be in the lower to mid 60s this afternoon which is several degrees lower than yesterdays. Some thunderstorms were developing over far western KY ahead of the warm front. Some high and mid clouds had moved into the forecast area ahead of the warm front but were dissipating late this morning. Temperatures are expected to continue climbing from the lower to mid 70s to the mid 80s to lower 90s by mid to late afternoon near average for this time of year.
1118 AM EDT Sat Aug 19 2017 Isolated to scattered thunderstorms will likely develop during the mid afternoon and early evening across the northwest Alleghenies and the central ridge and valley region before dissipating tonight.
We expect several days of this southerly flow, due to a somewhat unusual low off the southern California coast and high pressure over Texas.
This area will continue to be the focus through the early afternoon with the highest PoPs in the area.
1038 AM EDT Sat Aug 19 2017 Showers and thunderstorms are expected with the encroachment of an upper trough today. Convective activity emerging out of Ohio has weakened and diminished rapidly in coverage, but given the available boundary layer moisture and heating, rapid destabilization of under the encroaching upper trough should support convective redevelopment along the associated weak surface reflection/reinforcing front. A marginal severe risk remains, with inhibition via marginal shear and a lack of overall instability despite a decent mid level thermal trough.
1044 AM EDT Sat Aug 19 2017 Isolated to scattered thunderstorms will likely develop during the mid afternoon and early evening across the northwest Alleghenies and the central ridge and valley region before dissipating tonight.
624 AM CDT Sat Aug 19 2017 A broad area of high pressure across the Mississippi River Valley shifts eastward today resulting in mainly sunny skies and southwesterly flow developing at low levels. Temperatures will be warmer than yesterday with highs approaching 80. A cold front will track across the Upper Midwest tonight kicking off showers and thunderstorms across northern Minnesota, after midnight for north- central and northeast MN. The extended week ahead showcases an initial chance for additional precipitation before turning cooler and drier for much of the work week. A cold front associated with the precipitation will mainly impact the southern periphery of the forecast region with showers and thunderstorms possible.
1054 AM CDT Sat Aug 19 2017 Breezy south winds were bringing in very warm air this morning with highs ranging from the lower 80s far east to near 95 far west under sunny skies this afternoon. Main story for today will be the increasing heat as upper level ridging moves over the Dakotas. Used the HRRR for winds over north central SD this afternoon which highlights ridges much better.
/issued 343 AM CDT Sat Aug 19 2017/ Upper-air analysis and water vapor imagery this morning shows an upper ridge centered over southwest Texas with an upper trough over California. The ridging over Texas may not be strong enough to completely suppress convection across our forecast area today. Some of the high-res guidance shows convective signals focused on the southern Rolling Plains.
Not expecting thunder as cells should be quite limited in depth by the upper high and dry air aloft. /issued 438 AM CDT Sat Aug 19 2017/ SHORT TERM (Today through Sunday): Looking for any window for increasing moisture that might bring a chance of rain to the CWA but the stubborn 500mb Ridge is holding tight. Impressive looking 25H low over the S Florida and SE Gulf will be very slow in moving west against an equally strong ridge.
1035 AM EDT Sat Aug 19 2017 One cold front will pass east of Long Island this morning, while another passes through tonight.
The greatest coverage of thunderstorms should occur east to south of Tucson, but the lower deserts won't be completely left out. Surface dew points have jumped into the lower to middle 60s, up about 15 to 20 degrees over the past 24 hours.
724 AM EDT Sat Aug 19 2017 A weak cold front will move across the region Saturday afternoon and evening.
Temperatures aloft remained warm around -5C at 500mb, and a freezing level just below 17kft. It will be a hot day with highs in the low to mid 90s and heat indices 100-107F.
/issued 438 AM CDT Sat Aug 19 2017/ SHORT TERM (Today through Sunday): Looking for any window for increasing moisture that might bring a chance of rain to the CWA but the stubborn 500mb Ridge is holding tight. Impressive looking 25H low over the S Florida and SE Gulf will be very slow in moving west against an equally strong ridge.
748 AM EDT Sat Aug 19 2017 Aviation Clouds and scattered showers will exit this morning and high pressure will provide a sunny and warm weekend.
1007 AM CDT Sat Aug 19 2017 A quiet morning across the southern Tennessee Valley with a high pressure ridge at the surface and aloft building into the region. Stronger subsidence from this building ridge should really diminish any potential for diurnal convection this afternoon. The mostly clear conditions (along with some high thickness values) will allow highs to reach the lower 90s in most areas (a degree or so warmer than yesterday). As the trough axis in the Great Lakes and OH valley slides east, a more or less zonal pattern develops to our north, while an upper ridge at 500 mb bridges across the TN valley in a west to east fashion.
In the bigger picture, water vapor imagery and streamflow analysis indicate a trough digging into the western Great Lakes and lower OH valley. Three separate convective clusters were located along and west of the trough position in IA, MO, and AR. Some of the high cloud debris from the AR convection could move across today, but should be thin in nature. As the trough axis in the Great Lakes and OH valley slides east, a more or less zonal pattern develops to our north, while an upper ridge at 500 mb bridges across the TN valley in a west to east fashion.
725 AM EDT Sat Aug 19 2017 A weak cold front will move into the Piedmont this morning and will push slowly east across the Coastal Plain this afternoon before sagging just south of the area tonight and Sunday.
1252 PM EDT Sat Aug 19 2017 Thunderstorms are expected with the encroachment of a cold front this afternoon. Insolation in the wake of morning clouds and weak convection is destabilizing the Upper Ohio airspace under an encroaching upper trough. A slight severe risk/SPC -15%, was included in the HWO with pockets of dry aloft expected to enhance the severe potentail from marginal mid level flow and overall shear within the thermal trough. Building high pressure in the wake of the aforementioned system will result in a dry and seasonable Sunday with slightly lower dewpoints/humidity.
An upper level trough passing through Lower Michigan will keep a chance of showers and an isolated thunderstorm in the forecast during the morning. This will be mainly supported by a corridor of weak DCVA from south to north over the area downstream of the upper level trough axis. The passage of the upper level trough axis today will mark the beginning of a larger scale pattern shift toward a more zonal configuration to start the week.
Light onshore flow caused by weak systems passing to the north will provide some late night and morning clouds and slightly cooler temperatures through Sunday.
743 AM EDT Sat Aug 19 2017 Showers and thunderstorms are expected with the encroachment of an upper trough today. A marginal severe risk remains, with inhibition via a lack of overall instability despite a decent mid level thermal trough.
956 AM EDT Sat Aug 19 2017 A cold front will stall over the area today before moving offshore on Sunday.
710 AM EDT Sat Aug 19 2017 An upper level trough of low pressure will move east from the Upper Midwest and reach northern New England by tonight. Drier air moves in on Sunday with more sunshine expected and highs once again in the mid 70s to the lower 80s.
1159 AM EDT Sat Aug 19 2017 Aviation Clouds and scattered showers will exit this morning and high pressure will provide a sunny and warm weekend.
949 AM CDT Sat Aug 19 2017 Fog and low clouds continue to dissipate this morning, with plenty of sunshine expected for the remainder of the day under high pressure. Quiet conditions are expected this weekend under high pressure. As a sharp mid level wave exits to the east early this morning, high pressure will take charge, providing a quiet day with plenty of sunshine and warm temperatures. High pressure over the lower Great Lakes will hold sway in the lower levels, but its position to our east will allow for return flow with low-level thermal and moisture advection later in the day. The high's residual influence combined with low-level capping and the lack of a clear trigger support maintaining a dry forecast despite the arriving wave aloft.
945 AM EDT Sat Aug 19 2017 The upper low continues to spin just to the west of Florida. Weak Bermuda high pressure ridge axis remains across central FL with weak tropical waves in the region through the weekend with light winds and seas 2 feet or less.
Isolated diurnal convection may develop during the 19/17z-19/00z time frame near an elongated upper trough axis located near the Interstate 20 corridor. /issued 320 AM CDT Sat Aug 19 2017/ High pressure across the region to allow for hot temperatures today with highs forecast to climb into the mid 90s.
1021 AM EDT Sat Aug 19 2017 Under partly cloudy skies, temperatures are in the lower to mid 80s along the island chain. Surface wise, a ridge axis is draped over the Florida peninsula and the adjacent Atlantic and Gulf waters. These latter winds are associated with our region being on the eastern periphery of the massive mid and upper level low centered in the southeast Gulf of Mexico. Hence, low chance pops with high temperatures in the lower 90s seems on track. Vicinity showers are indicated at Marathon with some potential at Key West as initial morning activity evolves into focused cloud lines near the Lower Keys.
705 AM EDT Sat Aug 19 2017 A sharp upper level trough will push through the region today bringing isld showers to the area and perhaps a few rumbles of thunder. Upper level ridging looks to be in place for Eclipse Day leaving our region dry.
High pressure aloft will remain over the Four State Region as the center of the system moves into Texas and will allow daytime temperatures to climb in to the middle to upper nineties through the weekend. Isolated diurnal convection may develop during the 19/17z-19/00z time frame near an elongated upper trough axis located near the Interstate 20 corridor. /issued 320 AM CDT Sat Aug 19 2017/ High pressure across the region to allow for hot temperatures today with highs forecast to climb into the mid 90s.
634 AM CDT Sat Aug 19 2017 12Z TAFS Upper level ridging across the region will keep convective development below seasonal norms again today although isolated thunderstorms will be possible during the afternoon hours. At the surface broad high pressure across much of the gulf of Mexico will keep winds generally light and variable. /issued 340 AM CDT Sat Aug 19 2017/ Late night sfc analysis shows the area mainly under the influence of high pressure centered over the nwrn Gulf. All signs point to today being another hot and mostly dry day across the forecast area, thanks to lingering ridging in place mainly to our west. Still our resident ridging aloft should keep somewhat of a limit on convective development.
Warm advection aloft associated with this wave will promote the onset of light snow tonight south of I-70, especially in the ridges. A general dusting outside of the ridges can be expected, with up to 1-2" possible in the higher elevations. Persistent upper troughing will do nothing to dislodge the unusually-cold air in place. Wind chill values are not expected to fall to advisory thresholds except in isolated sections of the ridge zones, and wind will be weakening, so no headlines are expected at this time with respect to wind chill. Broad, but unusually-cold, upper troughing is forecast to maintain a cold airmass through the weekend with readings generally forecast about 10 to 15 degrees under the averages.
The 12z GFS is an outlier regarding a deep trof digging into the wrn Plains this weekend as the low currently south of AK phases with a trof currently over Hudson Bay region. For now, have kept PoPs capped in the low chance range with limited precip.
Wednesday and Wednesday night arctic high pressure will advance from the Missouri Valley to the Great Lakes, providing us with plenty of sunshine during the day Wednesday but with chilly temperatures. Wednesday night mid and upper clouds will increase ahead of a weak upper trof over the Plains, but it will still be a cold night with the heart of the cold dome of high pressure moving through, resulting in single digits and lower teens for lows. Because the center of the high will miss us to the north, we will maintain a breeze on the order of 5 to 10 mph tonight and Wednesday.
Cold high pressure at the surface is oozing south down the Plains this afternoon. However, the consensus and wpc opinion is to throw out the bitter cold GFS and go with the much faster cold front and drier/not as cold ECMWF and Canadian solutions.
A weak upper ridge pattern will amplify towards the weekend, allowing for mainly dry and mild weather to continue across Nevada for the remainder of 2017.
With the high centered over the state will see winds diminish to less than 5 mph and probably go light many places. Arctic high pressure centered from northwest North Dakota through southeast South Dakota this afternoon will propagate east to be centered just east of the I-29 corridor by Wednesday morning. This is not too far from the 12 UTC global consensus for lows for tonight, but, above the lowest edge of the forecast envelope which so far has not verified well on a large scale across the area.
A weak downslope wind across the western foothills will allow temperatures to be slightly warmer in the lower teens.
With the high overhead, winds will be light this evening. Warm air advection will begin to creep into western and central SD overnight as the high shifts to the southeast toward morning.
A ridge anchored over the West Coast will ensure a continuation of dry and generally mild conditions through the remainder of the month. Just made some minor tweaks to the sky grids for tonight to better account for the high clouds across the southern CWA and the next band of high clouds moving down from the northwest.
Have also kept forecast cloud amounts on the lower end again tonight and early Wednesday.
Arctic high pressure centered in the Dakotas and into Nebraska was supplying plenty of sunshine to the dvn cwa. Tonight and Wednesday: Arctic high pressure will settle into the cwa during this time frame.
Also, 1032mb high was located along the Mid Atlantic states with an associated ridge axis extending southwest to northeast gulf. In addition, a cold front was located from Virginia to West Tennessee to north central Texas. Upper air analysis continue to show a deep Hudson Bay low with prevailing westerly flow over the lower 48.
Persistent low stratus has remained across most of South Texas today, keeping temperatures on the cooler side this afternoon. An approaching cold front will move through the region overnight, bringing additional rain chances and colder weather to the region. Persistent CAA will allow temperatures to fall into the low to mid 40s most locations overnight, and upper 40s along the immediate coast.
High pressure building into the Upper Mississippi Valley.
The continued overrunning pattern will continue through the short term period as another cold front moves through tonight keeping winds northeasterly at the surface.
Forecast for tonight still on track as high pressure builds into Illinois. Broad troughing over North America is expected to be in place at least through the workweek. Rapidly moving weak disturbances plunging southeast into the trough base will impact our weather through that period with shots at snow followed by reinforcing shots of arctic air. Northwest winds will gradually turn northeast on Wednesday as high pressure passes to the north of central Illinois.
Finally, added some areas of freezing fog overnight.
Should clouds have enough influence on the overnight temps and it stays broken/overcast, we could see anywhere from three to seven degrees warmer by sunrise, rather than the colder, current forecast. Just adjusted hourly temperatures, RH and apparent temp grids to account for current warmer temps through about 4 am before temperature trends fall back in line with forecast lows. Chattanooga Airport, TN 27 40 25 42 / 0 0 10 10 Knoxville McGhee Tyson Airport, TN 24 35 20 39 / 0 0 0 10 Oak Ridge, TN 24 34 19 39 / 0 0 0 10 Tri Cities Airport, TN 21 30 12 37 / 0 0 0 10.
Otherwise temps overnight will be mild with lows ranging from the low 50s to lower 60s - about 10 degrees above normal for this time of year. Benign winds and seas prevail as a series of high pressure and fronts traverse the waters the next few days.
Have cooler highs for the eastern zones due to associated lingering cloud cover and warmer highs for the western zones due to a downslope component to the low level winds - around 40F west to teens east.
As a ridge builds near the west coast, we'll continue to see generally dry conditions with afternoon highs well above climate normals into the coming weekend. We may see a weakness currently embedded in the cirrus off the Baja coast undercut the base of the ridge over the weekend.