Aikyam-Lab/Synoptic-Bench huggingface dataset:
333 AM CST Wed Jan 10 2018 Water vapor imagery depicts a strong upper low INVOF SW AZ moving e. By 21Z today the mid/upper level trough axis will be just to the w and 7h-5h OMEGA fields suggest there will still be lift. Mid level winds veer strongly though between 21Z-24Z implying passage of the trough/onset of subsidence. Pattern then repeats with warmer wx Sun and another cold surge Mon which may persist thru Wed.
Not too much to update this evening with cloud cover and light winds over the mid state, along with a warm front still draped over the area. Warm front looks to currently be cutting the area in half, dividing the mid state into a northwest half and southeast half. Higher potential for fog exists north of the warm front, and for any areas south of the front that see decreased cloud cover.
18Z surface data has high pressure over the Ohio Valley with a developing storm system in the Rockies. Tonight, the low will likely occur between 7 and 9 PM. There may or may not be some patchy freezing drizzle north of highway 30. The first, the above freezing temps with rain the second post cold front environment with cold temperatures and chances for clippers through the period. Thursday AM, well above freezing temps along with strong H85 WAA will keep temps either steady or increasing overnight. As the cold front moves into the area a transition will occur with the rain changing to freezing rain and then to snow. Unlike our last freezing rain event, the road temps will be well above freezing limiting the affect of this freezing rain. This may lead to flash freezing of water on the roads.
1244 AM EST Wed Jan 10 2018 High pressure will cross the region overnight and move east of the area Wednesday.
/issued 243 PM CST Tue Jan 9 2018/ (Tonight and Wednesday) An upper level trough across the Desert Southwest will slowly track east toward West Central Texas tonight into Wednesday. Low temperatures will generally be in the low to mid 40s.
That said, thankfully, lows tonight will remain above the freezing mark, so freezing fog won't be an issue.
Upper level analysis places easterly moving trough over the Pacific Northwest stretching southward towards a cut-off low over southern California, while modest ridge remains over the midwest. Otherwise, a rather quiet night is expected as upper trough works its way over the Rockies. cold front sweeps through the area with temperatures falling through the day. Snow develops from northwest to southeast with the approaching trough, with a potential for a little freezing precipitation over the James River Valley before snow sets in. Snow will gradually taper from west to east overnight as the upper trough passes, but the gusty winds will bring continued blowing snow and frigid wind chill values.
That said given the cold ground temperatures, dew points in the low to mid 30s lifting northward, and fog already in place over much of southern Missouri and much of Illinois, advection fog is likely.
With warm temperatures ahead of the system, pcpn may began as rain, mixing with freezing rain before changing over to all snow with the Arctic front.
While just about everywhere has climbed above freezing, we still have a wide range of temperatures early this afternoon; from mid 40s where it has cleared out to just above freezing in VIH. Unlike last night, should see temperatures steady or slowly rise overnight so we are not looking at a freezing fog situation. We still have highs from the low 50s to upper 50s across the area. There will be a brief time period of a couple hours where the warm nose aloft will bring about a mix of sleet and freezing rain prior to the changeover to all snow.
Winds will be around 45 mph over the higher peaks this evening through the overnight hours. An upper trough is moving out of the CWA Wednesday evening.
Areas of fog likely to persist into Thursday, as even warmer air spreads into the area tonight. Initial surge of low level rh and warmer air aloft triggering patchy drizzle across the area. Temperatures at many locations still right around or slightly below freezing so will continue to mention -fzdz threat through the early morning. Will continue small chances for -ra as upstream cold front and trof approach from the west.
An arctic cold front situated over southern Alberta will move rapidly southeastward and arrive as the upper level storm system passes across western Kansas. Some light rain showers may develop ahead of the front in the evening if the lower levels are moist enough. Snow amounts could reach as high as 1 to 2 inches although with the expected 50 mph winds behind the cold front, you probably won't be able to get a good measurement given the drifting. Given the warm and wet ground initially, some melting and refreezing could lead to slick spots on highways.
Our low level flow will take on a downslope component Wednesday and Wednesday night, and low level flow will be on the increase as a strong cold front in the middle of the CONUS moves southeast toward us. If there is substantial sunshine, highs could be warmer than currently forecast.
12z guidance trended more northward with accumulating snowfall, basically spreading synoptic forcing across the baroclinic zone (cold front) further north and quicker than previous guidance. Will also be watching low level moisture advection tonight and the potential development of low clouds/fog, and possibly freezing drizzle/rain ahead of the cold front. The potential for freezing drizzle/rain is quite low at this point, but certainly possible given increasing synoptic lift through the morning hours coupled with low level saturation with little to no ice introduction.
Ridging will cause warm and humid conditions to prevail.
The local area currently resides under the subsidence region behind a large upper low moving through the eastern Gulf. The upper low will slowly translate eastward across south Florida and the Florida Straits before weakening. Meanwhile, an upper trough will further amplify as it passes through the Plains and into the Lower Mississippi Valley.
The low pressure system in southeast CO is deepening which is keeping southerly winds rather gusty at some locations, with recent gusts over 25 mph at TUL. The low clouds scattered out across northwest Arkansas, and far northeast Oklahoma. Latest water vapor/satellite imagery are sampling the upper level low pressure system across southern CA this evening. The abundant cloud cover associated with the system may interfere with high temperatures on Thursday and keep us a few degrees cooler.
As a result, isolated to scattered showers will be possible Thursday afternoon, with the highest chances over the interior from around Interstate 4 south.
However, we do have clouds/drizzle in the forecast mention as well, and temps above freezing.
Slow erosion is expected through the afternoon so have kept temps east of I35 much cooler than the west, where downslope flow will result in very warm afternoon highs. The mid to upper low, currently seen spinning over SW AZ, will traverse the Southern Rockies during the day and enter the panhandles this evening. Trends over the past several days have shown an increase in mid to upper level moisture accompanying a secondary trough mid day Thursday, especially over central and eastern OK. The mid level trough axis will move into eastern OK by 00Z Fri, along with the moisture so only expect a brief period of frozen precipitation. This will need to be watched closely, as it could fall in the form of freezing rain or snow.
Warming will continue through tomorrow morning, until a cold front starts impacting our eastern counties by 18Z, with the entire CWA being impacted with rainfall by 00z. Alongside the cold front, winds will start to pick up and shift with the passing frontal system. Wednesday Night-Thursday: A quick-moving upper short wave trough will move across the forecast area Wednesday evening and overnight, exiting the area Thursday morning.
/issued 229 PM CST Tue Jan 9 2018/ Despite upper ridge ovhd, relatively warm and moist air continues to overrun cold air at the sfc, resulting in thick cloud layer across much of the Lower MS River Valley today. Swly flow aloft fcst to increase, as upper low over srn CA continues to push ewd. Timing of the approaching upper low/cold front slightly slower than previous runs. Main line of convection should exit the region by late Thu night, but several model solutions indicate some lingering moisture wrapping around the n and nw side of the now closed upper low. The GFS continues to be the outlier on this facet, as it does not close off the trof. There does seem to be some evidence that some snow flurries will be possible, especially in the vc of the upper low.
This will bring more fog, drizzle or light rain to the area along with warmer temperatures for the middle and late parts of the weekend.
Tonight and Wednesday Main focus is on freezing drizzle and fog potential, along with cloud and temperature trends. This combined with minimal lift limits the potential for freezing drizzle. This could lead to some frost formation on roads and sidewalks tomorrow morning, especially over bridges and untreated roads. Air and road temperatures will rise above freezing by midday which will bring improvements to any slippery roads.
High pressure ridge sliding to the east today, and mostly zonal flow aloft with warmer temperatures advecting into the region continues the influence of a strong temperature inversion trapping a moisture rich airmass in place. Pattern shift as the low over the desert SW deepens and the flow across the CONUS amplifies.
An upper level ridge of high pressure will build into the area through late week, bringing a return to warm and dry conditions.
A warm front will move into the coastal waters Wed afternoon and sea fog will become more of a concern spreading inland.
An upper low is clearly seen in water vapor imagery over far western Arizona early this morning, and this remains the focus for the developing storm system over the Plains tonight. Rain will continue to expand over central Illinois Thursday ahead of the associated cold front, which will be crossing areas west of I-55 in the afternoon and reaching I-57 toward 6 pm. Temperatures ahead of the front should edge up a bit more and may even reach the lower 60s, while the northwest corner of the CWA will be about 30-35 degrees colder by late afternoon. The main concern with this system remains with freezing rain and the transition to snow post-front.
An upper level trough continues to move slowly across the area tonight. A cold front that moved through the area earlier has moved into Idaho and rain showers are winding down from the Blue Mountains eastward and should mostly end overnight. As a cold front has moved off to the east tonight and showers have ended, skies have become generally scattered in the west and broken in the east above 4000 feet AGL.
/Issued 931 PM EST Tue Jan 9 2018/ High pressure will continue overnight across the outlook area.
A developing warm front may bring MVFR/IFR conditions back into Galveston by 00Z as sea fog develops along the coast, but confidence in timing is too low to include mention in TAF at this time. A warm front will move into the coastal waters Wed afternoon and sea fog will become more of a concern spreading inland.
Low level pressure gradient does tighten a bit late in the day, but the resulting increase in wind speed will play more into warmer overnight lows.
Upper low/trof was moving into Arizona early this morning and will continue its eastward move during the day across New Mexico. The models remain consistent in lifting the Southwest CONUS upper trof northeast across Kansas tonight. A strong cold front will plunge southeast behind the departing low in the predawn hours. Though weakening as it moves southeast, this elevated frontogenetic zone should support light snow or flurries across south central and southeast Kansas into midday Thursday, as the southern portion of the central CONUS upper trof amplifies across the southern Plains during the day.
Warming will continue through tomorrow morning, until a cold front starts impacting our eastern counties by 18Z, with the entire CWA being impacted with rainfall by 00z. Alongside the cold front, winds will start to pick up and shift with the passing frontal system.
A weak area of low pressure is in place over the eastern Gulf of Mexico. A little subsidence on the back side of the trough will keep rain chances limited across the central and southern coasts, with 20-40 percent chances north and inland through the period. As we move into the medium to long range timeframe, weak upper cutoff low pressure will meander across South Florida, generating scattered cloudiness and a few showers. A weak pressure pattern will exist at the surface, with high pressure well northeast of the region and a weak trough axis over southern Florida.
Breezy southerly winds will help temps warm into the 60s over most locations and have nudged the forecast a bit warmer toward MOS guidance given the strong warm air advection expected.
Tonight, the resulting clear skies should allow temps to drop below freezing one more time, despite light southerly surface winds at daybreak Thu. Thu and Thu night, the PAH forecast area will be under a brief period of ridging aloft, providing dry and warmer conditions.
450 PM MST Wed Jan 24 2018 High pressure remains in full control of the weather over eastern Utah and western Colorado this Wednesday afternoon. The axis of the 500mb ridge will pass east of the Divide by sunset, allowing a few high clouds to move overhead. Regarding precipitation with this weak trough, the forecast remains on track for a relatively light snow event in the eastern Uintas as well as the central and northern Colorado ranges. 3" of QPF in the highest terrain, and accumulations will likely run in the 2-5" range from the Elks and Sawatch ranges northward to the Gore and Park ranges.
Should see VFR conditions for all terminals through 25/18Z, then am expecting MVFR CIGS to develop at KALI and KLRD AOA 25/21Z due to isentropic upglide as the coastal trough develops. On Thursday, an upper level trough will move out of the Big Bend and into the southern High Plains. A weak impulse at the base of this trough will approach South Texas tomorrow.
A midlevel ridge is currently building over the plains as a strong trough over the Pacific Northwest continues to progress eastward. It is these locations that will likely be slightly cooler than surround areas due to the snow pack inhibiting daytime mixing. Tomorrow the westerly midlevel flow over the eastern Rockies should promote a deepening lee trough. The lowest SREF member with minimum RH value is at 25 percent in central KS perhaps getting into the far southwest counties of the forecast area.
Warmer temps and gusty winds of 25 to 35 mph in the dry airmass will result in minimum RH values in the 15-25% range tomorrow afternoon, thus creating very hazardous fire weather conditions-especially for northeast Oklahoma.
846 PM EST Wed Jan 24 2018 An upper level trough will move across the area this evening.
914 PM EST Wed Jan 24 2018 Scattered snow flurries will continue over the southern tier and Finger Lakes region overnight, then high pressure will bring clearing skies for Thursday. Ridging at the surface will largely bring this activity to an end tonight, though a few flurries will persist over our far northern forecast area. With surface ridging not forecast to begin until tonight, we increased POPs for today and extended the lake bands farther to the south and east.
540 PM CST Wed Jan 24 2018 At 3 PM, a ridge of high pressure was located over the Upper Mississippi River Valley. The low clouds will persist through this evening and there are hints in the models that skies may gradually clear overnight. High temperatures on Thursday will be in the lower and mid 30s across the deep snow pack across parts of northeast Iowa, southeast Minnesota, west-central Wisconsin and north-central Wisconsin. Elsewhere the high temperatures will be around 40.
Temperatures have not warmed up much this afternoon as the low clouds and fog have been slow to dissipate with some areas of low clouds and fog remaining across northeast SD.
Satellite shows cold front moving eastward across Oregon this evening. The supporting upper trough will come fully inland Thursday night with more pcpn and colder temperatures.
Rain will continue to move north to south this afternoon/evening as a cold front passes over the Bay Area. Rain will turn into to showers behind the cold front tonight and will continue through the day Thursday.
Upper trough axis overhead now with sharp upper ridge over the Rockies. Otherwise, sharp upper ridge moves toward the area tonight.
Do not anticipate any issues with freezing drizzle but that will have to be watched if precip lingers longer than currently anticipated. High pressure will provide quiet weather Thursday and Thursday night. Stayed close to the blended model guidance for temps on Thursday with highs in the 40s to near 50 but took temps down below blended guidance Thursday night in the valleys as favorable radiational cooling conditions should allow valleys to fall deep into the 20s while ridges remain near freezing.
GAH PREVIOUS AFTERNOON DISCUSSION: Strangely and interestingly enough, reduced visibility in haze, frost, or freezing fog showed up in Wolf Point during the middle of the day. Felt it was best to include some patchy freezing fog in the lower Missouri River valley in the forecast for now through tomorrow morning. Thanks to a strong and broad upper level ridge of high pressure over the region as a whole, today's warmer temperatures and mainly dry conditions will persist through tomorrow (Thursday). As soon as Thursday afternoon, southwest flow aloft slides into eastern Montana, and a cold front moves eastward through the area by Thursday night.
A cold front will move through the Great Basin region tonight and Thursday, bringing some light snow to the area.
Aloft a trough will pivot north of the region overnight, with brief cold air advection by the early morning hours. Temperatures will drop by early morning into the mid/upper 20s across the higher terrain and to the low/mid 30s elsewhere. By the afternoon, ridging will build in from the west with winds veering to the NE.
High pressure is moving across the area tonight. Low temperatures were running several degrees cooler than expected this evening.
633 PM EST Wed Jan 24 2018 WV imagery and RAP analysis indicated mid/upper level ridging over UT through the nrn Rockies and a downstream trough over the Great Lakes into the OH valley. Otherwise, patchy sunshine prevailed over Upper Michigan as weak sfc ridging moves off to the east. Tonight, the combination of the shrtwv and weak trough may bring some light snow showers through wrn Lake Superior into the Keweenaw. Thursday, WAA will increase as the mid level ridge move eastward and low pressure develops into the plains. Mid/upper level ridging will advance through the cntrl CONUS to the Great Lakes from Wed into Fri as a trough moves through the wrn CONUS.
An upper low tracking to our north will slowly exit the region tonight. gusty winds will diminish and the low clouds will lift out of TYS and eventually TRI. While the low clouds are in place. Improving conditions are expected on Thursday with high pressure building in for clearing skies.
High pressure building in north of the waters will keep a tight pressure gradient in place across the eastern Gulf of Mexico through the rest of the week.
726 PM EST Wed Jan 24 2018 Showers and a few thunderstorms could affect or approach southern area terminals KTMB-KFLL through about 06z as a cold front slowly moves south of the area, along with possible periods of ceilings below 2,000 ft. morning lows will get a little cooler compared to previous nights with most interior and northern areas reaching the low- mid 50s, and most metro/coastal areas in the low 60s.
916 PM EST Wed Jan 24 2018 An upper level disturbance and associated dry cold front will move east across the region this evening. High pressure will follow the front through the end of the week. High pressure is forecast to build east over the region Thursday and Thursday night. Highs generally expected to fall closer to the cooler NAM guidance, mainly in the upper 40s to lower 50s. The best chance of rain appears to be tied to the track of the low pressure (either from the NE Gulf of Mexico NE along or near the coast, or a more offshore track).
Dry weather continues into Thursday as high pressure crests over the region. Thursday night will be another evening with below normal temps as the high crests aloft and we drop to the low single digits and below zero.
308 PM MST Wed Jan 24 2018 Current observations show downslope warming pushing off the Front Range through Denver Metro, while areas to the north are stuck in the low level inversions due to enhanced mountain wave clouds and snow cover. 700 mb temps rise to near +4C across the plains, and with further melting of the snowpack and weaker inversions daytime highs will be several degrees warmer. We should see a few spots in/near the foothills and parts of Denver push into the lower to mid 60s. Thursday night, an upper trough will move into Colorado bringing 60 to 70 mph wind gusts and snow chances to the northern and central mountains. Snow accumulations over the higher terrain will be between 2-6 inches, predominantly on west facing slopes and mountain peaks.
Otherwise, temperatures will be slightly warmer tonight (compared to last night) and tomorrow (compared to this afternoon).
1015 PM EST Wed Jan 24 2018 Canadian high pressure builds in for the rest of the week.
A broad mid level ridge builds over the northern Gulf and much of the southeast on Thursday.
Forecast confidence is medium: Southern Wisconsin will be within the western portion of high pressure tonight and Thursday. Above normal temps are expected Thursday as southerly winds develop on the western side of the high. Kept it a bit cooler where the recent snow fell, though it's hard to know how much of an impact the snow will have, especially since it's a relatively small area.
Will recommend to later shifts to re-evaluate western Converse county for potential inclusion in this highlight.
Upper heights will rise as ridging starts to build into the Plains overnight. Most of the high resolution models have fog redeveloping somewhere in the CWA overnight, just a question of where and how dense. The upper ridge moves east into the CWA tomorrow. Hopefully it is not just wish-casting, but think that there will be enough wind to bring clearing and mix some of the warmer temperatures down to surface.
A stationary trough of low pressure located in eastern Colorado will keep the winds out of the southwest for the time period.
/issued 310 PM CST Wed Jan 24 2018/ Sfc ridging practically overhead late this aftn has promoted light northerly winds to ensue, however plentiful insolation with only some thin cirrus has allowed for temps to warm mainly into the lower 60s per 21Z metars. Sfc ridging will slowly exit the region tonight, hence sfc winds will return to a southerly flow which will aid to keep overnight temps up into the lower 30s which is several degrees warmer than last night. Northwest flow aloft will give way to UL ridging tomorrow, coupled with a slight increase of 850 mb temps will lead to another above seasonal norm day /60s CWA-wide/.
Temperatures were at or above freezing at 20Z with the warmest readings found in snow free areas of the south as expected. Even warmer temperatures are expected on Thursday as an upper ridge moves over the region.
Tonight should be a repeat of last night with some high clouds moving across SE Texas but the airmass remains dry with high pressure over much of the area. A few spots may reach the freezing mark for a few hours for a light freeze. Onshore winds will return on Thursday as the high moves east.
Clouds will slowly break up as we head into Thursday morning and sun will be able to break through during the day Thursday with high pressure around.