Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/28/23

Area Forecast Discussion
National Weather Service Amarillo TX
655 PM CDT Mon Mar 27 2023 ...New AVIATION... .SHORT TERM ... (This evening through Tuesday night) Issued at 257 PM CDT Mon Mar 27 2023 Outside of breezy winds this afternoon through this evening, fairly quiet weather is expected through Tuesday night. A cold front will cool down temperatures and highs tomorrow will be in the 50s. Outside of a small chance for a stray shower in the northern OK Panhandle later today, dry conditions will persist. So far this afternoon, southerly to westerly winds continue across the Panhandles with gusts up to 25 to 30 mph across the CWA. Some scattered cumulus is beginning to develop and move eastward across the Oklahoma Panhandle at the time of this writing. KAMA radar is starting to pick up on some very light returns associated with these clouds and they could produce some very light precipitation later on this afternoon/evening. Based on the 27/18z RAP H500 mb analysis, a shortwave trough is moving across central CO and entering western KS early this afternoon. This feature is aiding in developing the clouds mentioned above across the OK Panhandle into western KS. Just enough PVA at the base of the shortwave may move over the far northern OK Panhandle. Some mid level moisture looks to remain over this area when looking at forecast soundings, so some light precipitation may fall across this area this evening. Main limiting factor would be the dew point depressions at the surface, which may be too large for any precip to reach the surface. Either way, have kept low end mentions of PoPs across this area to account for the possibility. A cold front will move across the Panhandles later this evening and northerly winds will prevail behind the front. H850 temperatures behind the front will fall down to near or just below 0 C tonight. Below freezing temperatures are expected area wide and some locations in the north may drop down into the lower to mid teens. Southerly winds will return tomorrow afternoon and the cooler air will begin to retreat to the north and east. Highs will be cooler tomorrow, with highs in the 50s, and will be well below average for late March. A 45 to 50 kt low level jet will form over the Panhandles on Tuesday night and breezy winds are expected heading into Wednesday morning. Muscha && .LONG TERM ... (Wednesday through next Sunday) Issued at 257 PM CDT Mon Mar 27 2023 Key points: The main area of concern for the long-term will be high wind and fire weather on Thursday and Friday. A secondary cause for concern is severe weather potential on Thursday in the east, but there are uncertainties that lower confidence in it occurring in our area. Details: Heights aloft will be rising on Wednesday ahead of a large West Coast upper-level trough. Highs will largely be in the low to mid-70s across the area with breezy southwesterly winds. A cold front pushes into southwest Kansas Wednesday evening, with NAM being the most aggressive by pushing it into the northern Oklahoma Panhandle. The models have been too timid with cold fronts pushing south lately, so won`t be surprised if we ultimately see the cold front push through the Oklahoma Panhandle. It would still be unimpactful aside from some cooler lows for those behind the front. Lee cyclogenesis will begin Wednesday night off to the northwest in response to the approaching upper-level trough, intensifying in the afternoon, culminating in a sub-1000mb surface low. The surface pressure gradient will tighten, resulting in 20-30 mph sustained southerly winds across most of the area Thursday, with 30-35 mph southwesterly winds in the northwest. A 700mb jet will move through the area in the afternoon, and forecast soundings show that tapping at least into that layer shouldn`t be an issue for most. The area of greatest concern for winds is in the northwest, where mixing is expected to be deepest, perhaps up to 600mb. Additionally, the northwest will be in the right exit region of the 500mb jet streak, introducing subsidence which should help bring some very strong winds aloft down. Currently forecasting wind gusts to reach or exceed 55 mph in that area. Later in the day, while the wind and fire threats are ongoing, severe weather may join the mix. The main question right now is about where the dryline will be. Currently, most guidance shows low to mid-50 dew points will hang on in the southeastern counties. GFS has been trending toward higher dew points, with 12z GFS bringing in upper-50 dew points. In any case, forecast soundings show that the cap may erode by 7 pm, but with weak 0-3km lapse rates, instability should stay below 1000 J/kg. Between the modest instability and the idea that convective initiation will likely occur in the eastern half of the Texas Panhandle, confidence isn`t high that storms will be able to strengthen to severe threshold before moving out of the area. However, won`t rule out a severe thunderstorm. Will monitor trends as the severe weather threat would increase if the dryline trends west. 20-30 mph sustained winds will remain through the evening, and combined with the subsidence of the right exit region, some areas could stay mixed post-sunset. If this scenario does pan out, strong wind gusts could continue because 700mb winds are expected to strengthen in the evening. A tight pressure gradient will remain for the Panhandles Friday, resulting in 30-35 mph sustained winds in the southern half of the Texas Panhandle. 700mb winds will strengthen in the afternoon, and again, we should be able to mix up to or beyond that layer. We will still be seeing subsidence associated with the jet streak, but this time with the left entrance region. Therefore, wind gusts up to or exceeding 55 mph will be possible in the southern half of the Panhandles. The trouble-making system will move out of the Plains on Saturday and we`ll return to quiet weather. Some models are hinting at a shortwave moving through the area at sometime on Sunday. However, there may not be enough time between systems to get sufficient moisture return for a chance for precip. Deterministic models, backed up by their respective ensemble means, are suggesting another upper-level trough will dip down into the Western US on Tuesday. This could produce some kind of weather later next week. Vanden Bosch/Goehring && .AVIATION... (00Z TAFS) Issued at 644 PM CDT Mon Mar 27 2023 For the 00Z TAFs, a cold front will move south of KAMA by the beginning of this cycle with gusty north winds to around 40 knots for a few hours this evening at the terminal sites. An Aviation Weather Warning is in effect until 04Z for KAMA. In addition, areas of blowing dust will accompany this front, resulting in locally reduced visibilities to around 5 miles at times early this evening. Winds will diminish late tonight, then become southeast to south Tuesday afternoon. 02 && .FIRE WEATHER... Issued at 257 PM CDT Mon Mar 27 2023 Thursday, fire weather concern will be greatest in the northwest. RH values are forecast to be in the upper single digits. Combined with 30-35 mph sustained southwesterly winds, RFTI could be as high as 8 in Cimarron county. Wind gusts could reach or exceed 55 mph. Fire weather could continue through much of the evening as winds will only weaken to 20-30 mph and RH values remain below 15%. Friday, the concern shifts into the southern half of the Texas Panhandle. 30-35 mph sustained westerly winds are expected with RH values in the upper single digits. Currently forecasting RFTI values of 7 to 8 for that area. Wind gusts could reach or exceed 55 mph. && .PRELIMINARY POINT TEMPS/POPS... Amarillo TX 24 55 34 73 / 0 0 0 0 Beaver OK 21 53 34 72 / 10 0 0 0 Boise City OK 16 51 34 71 / 0 0 0 0 Borger TX 25 57 36 76 / 0 0 0 0 Boys Ranch TX 23 56 33 75 / 0 0 0 0 Canyon TX 24 56 33 73 / 0 0 0 0 Clarendon TX 28 56 33 73 / 0 0 0 0 Dalhart TX 19 52 30 72 / 0 0 0 0 Guymon OK 19 53 33 72 / 0 0 0 0 Hereford TX 23 57 32 74 / 0 0 0 0 Lipscomb TX 23 53 33 73 / 0 0 0 0 Pampa TX 24 54 33 73 / 0 0 0 0 Shamrock TX 28 56 31 71 / 0 0 0 0 Wellington TX 30 56 32 71 / 0 0 0 0 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...Red Flag Warning until 8 PM CDT this evening for TXZ001-006-011- 016. OK...Red Flag Warning until 8 PM CDT this evening for OKZ001. && $$ SHORT TERM...05 LONG TERM....52 AVIATION...02
Area Forecast Discussion
National Weather Service Billings MT
244 PM MDT Mon Mar 27 2023 .DISCUSSION... Tonight through Tuesday... Radar showed a few convective snow showers along the NE Bighorns this afternoon, otherwise the snow had stopped across the area, with low clouds breaking up. SREF kept the airmass unstable from 700-500 mb tonight into Tuesday under cyclonic flow. The instability will support a few evening snow showers over the Beartooths/Absarokas and NE Bighorns. Otherwise, energy moving through the cyclonic flow will push a back door cold front into the NE zones overnight with a 20-30% chance of snow for areas from NE Musselshell County ESE through KMLS and KBHK. The probability for greater than an inch of snow for these areas was less than 10%. HRRR also suggested patchy fog from around K3HT to KBIL to KSHR E, so added this to the grids through early Tuesday. Gusty SSW winds will develop at KLVM and Nye late this evening as the pressure gradient tightens up. However the gradient will not be very strong and 700 mb winds will only be 20 kt based on the NAEFS. Thus, kept wind speeds sub-advisory and will continue the wind chart for 50 mph winds for KLVM. A 20-30% chance of snow will develop over and near the mountains Tue. afternoon due to low- level upslope flow and moisture advecting in from the W. Lowered temps below the NBM tonight and Tuesday due to the heavy snowpack. Arthur Wednesday through Monday... Main forecast concerns are periods of snow late Wednesday into the weekend. Overall forecast confidence is high through Friday. WPC Cluster members are showing overall good agreement in the large scale pattern over the western CONUS. Consulting NBM probabilities for greater than 2 inches of snow, probabilities are indicating high chances (50-80%) of exceeding 2 inches of snow over the mountains/foothills areas of south central Montana, including the Absaroka/Beartooth, Pryor, and Bighorn Mountains. The probability for exceeding 6 inches is very low (20%) and mainly confined to higher elevations above 8 kft. Consulting ECMWF Ensemble members, the timing for the onset of snow at Red Lodge looks to be between 12 and 18Z on Thursday with an ending time of around 18 to 00Z Friday. Expect some travel impacts from this light snow event. Flow aloft looks to transition to more zonal late in the weekend with temperatures moderating just a bit. Saturday looks to be the warmest day with a chance (~50%) for highs to exceed 50 degrees at Billings. With the possibility for these warmer temperatures, this may create increasing runoff into area rivers, possibly increasing the potential for ice jams. The next chance for precipitation looks to arrive later Saturday into Sunday with the potential for mountain snow and some rain at times in the lower elevations. && .AVIATION... Expect areas of MVFR ceilings into this evening, otherwise conditions will be VFR. A 20-30% chance of snow will move into KMLS and KBHK by 03Z and move E of the area by 12Z. MVFR/IFR conditions are possible with the snow. Patchy fog will develop overnight and persist into Tuesday morning. SSW surface winds will increase at KLVM tonight with gusts to 40-45 kt, and diminish Tue. morning. Expect areas of mountain obscuration this evening and on Tuesday. E flow will develop Tue. afternoon, bringing in MVFR/IFR ceilings. Arthur && .PRELIMINARY POINT TEMP/POPS... Tue Wed Thu Fri Sat Sun Mon ----------------------------------------------------------- BIL 013/030 017/035 024/036 024/044 031/050 030/045 024/041 01/E 10/E 26/S 31/B 01/B 34/S 44/S LVM 015/037 020/037 027/037 022/045 030/048 028/041 022/038 02/S 11/E 47/S 21/B 13/O 55/S 55/S HDN 009/033 014/039 018/036 021/043 023/051 026/046 021/043 01/B 10/B 26/S 51/B 01/B 34/O 44/S MLS 018/030 015/044 025/041 022/043 028/055 033/049 026/042 20/E 00/U 12/S 21/B 00/B 22/O 23/S 4BQ 018/034 017/045 025/043 024/041 026/056 032/048 027/044 00/B 00/B 13/S 52/S 00/B 22/R 33/S BHK 011/025 007/037 019/037 016/036 021/051 027/046 022/039 30/B 00/U 12/S 21/B 00/U 22/S 23/S SHR 005/031 012/037 018/035 019/037 018/046 023/040 017/037 00/B 10/B 16/S 72/S 00/B 23/S 44/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Corpus Christi TX
835 PM CDT Mon Mar 27 2023 ...New AVIATION... .SHORT TERM... (Tonight through Tuesday night) Issued at 303 PM CDT Mon Mar 27 2023 Key Messages: - Patchy sea fog expected through the night - Marginal Risk of Severe Weather this afternoon across the Victoria Crossroads - Marginal Risk of Severe Weather on Tuesday for the southern half of the CWA MSAS analysis reveals a frontal boundary stalled out to the north of the CWA. This feature has been sitting there through much of the day as upper level forcing has been lacking to push it further south. Meanwhile, onshore flow continues to funnel low level moisture into the region. This morning`s KCRP 12Z sounding showed PWATs of 0.86". The few GOES TPW pixels that can be seen through the dense stratus indicates those numbers have risen to near 1.45" across the Coastal Bend. A few spotty showers can be seen on radar as of writing. Would expect a slight increase in cover, generally east of Highway 281, with potentially an isolated thunderstorm mixing as instability continues to climb. In addition, patchy fog has been lingering along the coast through the day. Visibilities have generally ranged from 2- 4 miles with a few spots dropping below 1 mile at times. This trend will continue through this evening with SREF probs adding higher confidence to dense fog developing overnight. As we head into the overnight period, an upper level shortwave will provide the forcing need to push the front further south. The front looks to be across our northern tier of counties by 12Z and pushing offshore by mid day. SPC currently has the majority of South Texas in a Marginal Risk for Severe Weather tomorrow. It looks like we have potentially 2 rounds of showers and storms: 1) Showers and thunderstorms will be possible during the morning hours as low level forcing is increased maximized the boundary along with support aloft via mid to upper level shortwaves. Sufficient instability (2500+ CAPE), shear (40-50 knots), and mid level lapse rates near 8C/km would support a hail and winds threat. A few select soundings do show over 1000 DCAPE with a rather moist low level profile. Recent runs of the HRRR have been inching further south towards Deep South Texas with this first round of storms. This is similar to where the 12Z HREF shows the highest probabilities for heavy rainfall. This round of activity looks to clear the region during the early afternoon hours 2) Isentropic lift around the 305K level will keep some moisture in place across the region. During the evening and overnight hours, another shortwave will rotate through the region as the RRQ of a jet streak passes by. This upper level forcing, along with some elevated instability, should be enough to encourage another round of convection. Any convection that does develop will fizzle out at our support leaves the area during the early morning hours Wednesday. After a mild night tonight, we are in store for a slight cool down behind the front. Highs on Tuesday will struggle to reach the mid 70 with lows falling into the mid 50s inland overnight. && .LONG TERM... (Wednesday through next Sunday) Issued at 303 PM CDT Mon Mar 27 2023 Key Messages: - Chance of showers continues through Wednesday, then isolated showers or thunderstorms will be possible at times across the Rio Grande Plains the remainder of the week. - Temperatures more seasonal Wednesday then warming back up to above normal the rest of the week. - Minor coastal flooding and moderate to high rip current risk possible Wednesday and Thursday. Sufficient moisture behind Tuesday`s front will continue into Wednesday with models indicating a weak isentropic upglide pattern developing. Combined with an embedded upper level short wave in a quasi-zonal west flow aloft moving east across S TX Wednesday, will contribute to scattered showers on Wednesday. MOdels indicate some drying in the mid levels by Wednesday afternoon with the rain diminishing across the area. Overnight Wednesday, low level flow across the Rio Grande Plains is progged to strengthen from the south and southeast. This will strengthen isentropic lift across the western CWA and will combine with yet another short wave aloft to bring a slight chance to chance of showers. At the surface, a southeast to south flow will strengthen across S TX through Thursday, bringing moisture and warmer temperatures back into the area through the remainder of the week. A mid level high pressure system centered along the coast of Mexico is progged to shift east toward the Yucatan as an upper low swings across the Midwest Thu/Fri. This will bring a long wave trough toward TX the latter part of the week which will push a weak cold front and/or develop a surface trough across S TX Saturday. This will lead to a slight chance of showers, possibly a thunderstorm or two by the weekend. A weak to moderate northeast then east flow Wed into Thu may lead to minor coastal flooding and/or moderate to high rip current risk. Confidence is low that this will occur as swell periods are progged to be around 6-7 seconds, but the NWPS Rip Current Probability shows an increase in swell heights. In addition, P-ETTS shows an increase in tide levels Wed/Thu. && .AVIATION... (00Z TAFS) Issued at 828 PM CDT Mon Mar 27 2023 Expect a mixture of MVFR/IFR ceilings tonight through early Tuesday morning, along with weak onshore flow. Expect areas of fog with MVFR/IFR visibilties near the immediate coast. Scattered showers and isolated thuderstorms, with brief IFR ceilings/visibilities, are expected to develop from north to south across South Texas along and in advance of a cold front, during the approximately 10-16z Tuesday period. Afterward, predominate MVFR ceilings/VFR visibilities, with moderate/breezy north/northeast wind, which will continue until the end of the TAF period. && .MARINE... Issued at 303 PM CDT Mon Mar 27 2023 Patchy sea fog is expected to linger along the coast through this evening with visibilities generally ranging from 2-4 miles. Another round of patchy fog is possible late tonight ahead of an approaching cold front. A cold front will move across the coastal waters Tuesday and bring a chance for showers and thunderstorms. Northeast winds will increase to around 20 to 25 knots behind the front. A few gusts to gale will be possible across the offshore waters. Winds will begin to relax through the morning hours Wednesday. Moderate northeast winds will continue over the Gulf waters Wednesday along with a chance of showers. The flow will become easterly Wednesday night and southeasterly by Thursday. Moderate to at times strong onshore flow is expected through the remainder of the week. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 68 76 58 70 / 30 40 50 40 Victoria 64 74 56 69 / 40 20 30 30 Laredo 67 73 57 67 / 50 60 40 30 Alice 65 76 56 69 / 30 40 50 40 Rockport 66 77 60 72 / 30 30 40 30 Cotulla 65 76 56 69 / 40 40 30 20 Kingsville 67 76 58 70 / 20 50 50 40 Navy Corpus 67 76 62 72 / 30 50 60 40 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...Small Craft Advisory from 10 AM to 7 PM CDT Tuesday for GMZ231- 232-236-237. Small Craft Advisory from 10 AM to 10 PM CDT Tuesday for GMZ250- 255. Small Craft Advisory from 10 AM Tuesday to 3 AM CDT Wednesday for GMZ270-275. && $$ SHORT TERM...TC LONG TERM....TE AVIATION...WC/87
Area Forecast Discussion
National Weather Service State College PA
1155 PM EDT Mon Mar 27 2023 .SYNOPSIS... Drier and cooler conditions move in for Tuesday. A cold front will cross the region Wednesday night with rain and snow showers followed by cold conditions on Thursday. The weekend looks milder but unsettled with widespread showers. No fooling, April will arrive with rain, a threat of storms, and a big drop in temperatures as a cold front sweeps through. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Precip has largely moved east of the area. Clouds linger mainly across the NW and Laurels. Some drizzle or light snow flurries are possible in these areas, but most spots will stay dry. Temps will dip to mins in the upper 20s across the north and mid to upper 30s in the SE Valleys. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... Zonal flow and the passage of a SW-NE ridge of sfc high pressure brings mainly dry and cooler than normal temperatures for the bulk of the time Tuesday and Wednesday. Some waviness in a zonal upper level pattern may produce a few showers on Tuesday night. Any such accumulation would be minimal with rain across the south and perhaps some snow farther north. A cold front will bring a brief period of precipitation Wednesday afternoon and evening for most of the region. With a deep layer of steep lapse rates ahead of the strong front, a linear band of heavier rain and snow showers is possible, potentially making for slick road conditions north of I-80 if it comes in towards/after dark. Temps drop off quickly in the wake of the cold front with winds gusting to 35 or 40 mph in the northwest mountains. Winds stay up overnight and Thursday morning will be the coldest of the week with temperatures near 20 up north and near freezing in the southeast. && .LONG TERM /THURSDAY THROUGH MONDAY/... In the wake of the cold front, expect a brief cool down, with high temperatures on Thursday running a few to several degrees below normal. It will be quite dry as well with plenty of sunshine. RH values will dip into the 20s percent Thursday afternoon and could even drop into the teens. Although winds will be lighter, there may still be gusts above 20 mph especially through the Susquehanna valley. High pressure will slide off the East Coast Thurs night, with a southerly flow developing. This should lead to significantly milder temperatures for the end of the week and into the first part of the weekend. Current guidance supports temperatures in the 50s and 60s on Friday with an additional 10 degrees added to those highs on Saturday afternoon. The realization of such warm temperatures on Friday and Saturday will be dependent on the extent of precipitation during the day and how quickly a strong cold front moves through. There remains some uncertainty in timing and extent of precipitation, but confidence is high in a widespread soaking rainfall and mild temperatures. Widespread stratiform rain during the Friday and Friday night timeframe will precede the arrival of a strong cold front. As the front sweeps through, timing will be important for the potential threat of severe weather. Arrival in the afternoon during peak heating on Saturday would lean toward more storms and perhaps higher severe weather chances. Earlier/later arrival in the morning or late evening would limit the severe threat, but it bears watching. Ahead of and after the cold front sweeps through, expect gusty winds to develop thanks to a deepening surface low over Quebec. The wind threat looks formidable with this system and gusts in excess of 40mph appear plausible for most of the area. Temperatures will drop of considerably by Sunday with 24 hour temperature changes forecast to be -20 to -30 by Sunday morning. High pressure builds in for Sunday, bringing plenty of sunshine, calmer winds, and gradual warming into the first full week of April. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... The main focus overnight will be on developing low cigs across the W Mtns associated lingering low level moisture and an upsloping northwest flow. Observations at 03Z show a ribbon of IFR cigs extending from Ohio across the western NY state. The latest RAP 925mb 90pct RH fields, which align well with this area, suggest IFR/LIFR cigs over NW Mtns will expand southward into the Laurel Highlands by around 05Z-06Z. Ensemble prob charts indicate IFR/LIFR will then remain likely through early Tuesday morning over the W Mtns. Elsewhere, a downsloping northwest flow should yield progressively better conditions downwind (southeast) of the Alleghenies, with VFR conditions likely across the Susq Valley. High pressure building in from the Grt Lks should result in rising cigs/breaking clouds across central PA Tuesday. Model RH profiles and ensemble probs suggest VFR conditions are likely across the entire region by afternoon. However, borderline high MVFR/low VFR cigs appear likely to linger over the NW Mtns until early evening. Outlook... Wed...Evening snow squalls possible, mainly NW Mtns. Thu...No sig wx expected. Fri...PM rain/low cigs possible, esp NW Mtns. Sat...AM showers/reduced cigs possible, then turning windy. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/Colbert NEAR TERM...Lambert/Colbert SHORT TERM...Lambert/Colbert LONG TERM...Colbert/Banghoff AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Dodge City KS
538 PM CDT Mon Mar 27 2023 ...UPDATE TO AVIATION... .SHORT TERM...(This evening through Tuesday night) Issued at 338 PM CDT Mon Mar 27 2023 This afternoon, a compact yet intense storm system was moving across northeast Colorado into adjacent far northwest Kansas and far southwest Nebraska. RAP analysis was showing very cold 500mb temperatures with this system -- as cold as -37C in the cold pocket across the northern Colorado Rockies. This resulted in very steep lower and mid level lapse rates with surface-based Lifted Indices right around zero or slightly below zero (upwards of 100 J/kg CAPE) across some portions of the eastern Colorado High Plains. Showers continued to develop during the mid afternoon hours across eastern Colorado into far western Kansas, but observations and RAP analysis were showing precipitation type as rain southeast of roughly Cheyenne Wells to La Junta, CO line. As the system continues to move east, the freezing level will drop across a larger portion of west central and some portions of southwest Kansas (down to 1000 feet AGL or lower), supporting dominant precipitation type of snow. Most areas northwest of a Garden City to La Crosse line should see wet snow around sunset, but the longevity of the precipitation event as snow will not be very long, thus no impacts are expected with the snow -- other than perhaps a couple slick bridges and overpasses as the sun lowers and precipitation rates are high enough. Precipitation will end across our forecast area late tonight, around 03 or 04Z. There will be a brief period of fairly strong northwest wind up until late tonight, but after 05Z or so, winds just about everywhere will drop to 10 mph or less. As we head into Tuesday, surface high pressure will be centered across the western half of Kansas leading to light and variable winds. Temperatures will be slow to rebound through the 40s, but by late afternoon with some insolation, we should see afternoon highs top out around 50 to 53 degrees. .LONG TERM...(Wednesday through Monday) Issued at 338 PM CDT Mon Mar 27 2023 Sensible weather at the beginning of the Long Term period will be largely the result of the next big storm system approaching the western Great Plains Thursday and Friday. In between storm systems on Wednesday, we will be watching for a sneaky cold front to push south, thanks to a subtle shortwave trough rotating around the southern periphery of a larger polar gyre centered across central Canada. An anomalously cold airmass awaits upstream, so this front on Wednesday could really disrupt the current temperature forecast. Latest models today now show a stronger cold front and stronger low level cold air advection as a result. There will likely be a 35- degree surface temperature gradient across the front Wednesday afternoon (30s north of the front across southern and central Nebraska to around 70 across southern Kansas). The current forecast calls for a high in the mid 50s along I-70 on Wednesday, but that could very well be early in the day with falling temperatures in the afternoon. This is one component of the forecast that will likely see some continued modification as we get closer to Wednesday afternoon. The cold front will reach a terminus some time Wednesday evening across southwest Kansas. The front will stall out then begin to lift back north Wednesday night as a warm front, thanks to the approaching storm out west. The initial southwest flow aloft will impinge on the High Plains early Thursday with a deep leeside trough developing as a result. Wind speeds will increase and temperatures likely will, too, during the night. Most areas may be waking up to temperatures in the upper 40s to lower 50s along and south of the Arkansas River Thursday morning. Winds will only further increase in strength during the day Thursday as a deep surface low forms within the leeside trough across east central Colorado-far west central Kansas. Low level Gulf of Mexico moisture will be increasing out of the south thanks to the intense low level jet with lower to mid 50s surface dewpoints by late afternoon across the eastern half of the DDC CWA (along and east of U283). The latest NBM winds are showing afternoon winds 30 to 40 mph sustained on both sides of the dryline. Gusts in excess of 50 mph are looking more and more likely especially along/west of the dryline where mixing depth will be greater. Blowing dust will be in the grids where current wind gust forecast is in excess of 45 mph. The next question centers around probability of severe weather across south central Kansas east of the dryline. The Day 4 SPC Convective Outlook has a 15% area including our southeastern counties, although this may be a bit ambitious, as a capping inversion due to a fairly robust elevated mixed layer (EML) will be in play. It would take some intense mid level cold advection to erode a strong EML as suggested by some of these early model runs. The latest EPS 500mb height anomaly fields for 00Z Friday show the greatest negative height anomalies still way out across western Arizona into Utah, which would certainly support a mid level cold front well to the west of the dryline late Thursday. It would not be too surprising to see the next SPC Convective Outlook pull back a little bit on the 15% risk area given this timing issue and such strong convective inhibition east of the dryline Thursday evening. The best forcing for ascent will be coming out across western Kansas some time early Friday morning, and by that time, the low level wind field will be veering out too much pushing all the Gulf of Mexico moisture too far east into southeast Kansas. GEFS and EPS 500mb anomaly fields for 18Z Friday are in pretty good agreement with negative height anomaly centered from northwest KS into southwest NE, so any cold sector precipitation on Friday will be confined to far northwest KS into western Nebraska. As such, a dry forecast will continue for west central and southwest Kansas behind this low. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 535 PM CDT Mon Mar 27 2023 MVFR cigs will linger in vicinity of KHYS, KGCK, and KDDC through early evening as a band of low level stratus shifts eastward across southwest and central Kansas. Periods of light rain/snow can also be expected. Otherwise, widespread VFR conditions are expected to develop overnight and persist through early Tuesday. Northwesterly winds around 15 to 30kt are forecast to develop immediately behind a cold front moving through southwest/central Kansas this evening, then subside overnight. && .FIRE WEATHER... Issued at 338 PM CDT Mon Mar 27 2023 Along and west of the dryline on Thursday, critical fire weather conditions are appearing more and more likely as there is high confidence in both very strong southwest winds and very low relative humidity. Latest forecast will continue to show minimum afternoon relative humidity in the 10 to 15% range generally west of Highway 83 to the Colorado border. The SPC Fire Weather Outlook already has a 70% Risk area for Critical Fire Conditions across our far southwest counties. Placement of the dryline from mid afternoon through early evening will certainly be very important in how far 3-hr or longer Critical conditions can extend east/northeast across southwest Kansas. We will also have to watch the Oklahoma border county areas Friday afternoon, depending on how far south the cold front will reach, as south of the cold front Friday afternoon there will likely be another day of large scale Critical Fire Weather. SPC Day 6 Outlook (Valid Friday) has an even larger area of 70% Critical risk area encompassing the Texas and Oklahoma Panhandles, bordering on the Kansas state line. && .PRELIMINARY POINT TEMPS/POPS... DDC 22 52 33 67 / 20 0 0 0 GCK 19 51 31 62 / 10 0 0 0 EHA 19 53 35 70 / 0 0 0 0 LBL 20 53 31 70 / 10 0 0 0 HYS 21 51 30 57 / 60 0 0 0 P28 27 54 30 69 / 30 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...JJohnson FIRE WEATHER...Umscheid
National Weather Service Eureka CA
258 PM PDT Mon Mar 27 2023 .SYNOPSIS...A potent cold front will bring strong and gusty south winds to Northwest California tonight. Winds will diminish after frontal passage early Tuesday morning, however gusty winds will redevelop by Tuesday afternoon as a compact low approaches from the northwest. Heavy snow is forecast tonight, generally above 2000 feet, and will impact the region Tuesday through Wednesday. Colder and drier conditions are forecast for the latter portion of the week, before another weaker system brings lighter amounts of rain and mountain snow next weekend. && .DISCUSSION...A surface low has been developing just west of 130W almost due west of Pt St George and moving NE this afternoon. This area of low pressure will continue to deepen this afternoon and evening (down to 992mb) while an occluded surface boundary moves toward the North Coast. Several higher elevation RAWS have been reporting gusts around 50 mph this afternoon, while a few coastal headland sites (KCEC) have reported gusts near 55 mph. High resolution model guidance continues to indicate a coastal barrier jet strengthening to 60-70kt late this afternoon into this evening as the occlusion approaches. HRRR surface gusts ramp up to 52-63mph across the coastal plain this evening. A high wind warning for gusts to 60 mph or more for the coastal Humboldt and for gusts to 70 mph or more for the higher elevations of Humboldt remains in effect through the late tonight. HRRR and multi-model blended guidance shows wind dropping off significantly after frontal passage, between about 2 to 4 AM. Elsewhere, a wind advisory remains in effect for gusts to 45 to 55 mph, primarily for the upper elevations and ridges. Portions of the Mendocino and Del Norte County may also have stronger wind gusts to 60-70mph and an upgrade to warning may be necessary this evening. Later this afternoon and evening frontal precipitation moves onshore. The big challenge of the forecast is the snow levels. For now it looks like the snow levels will be around 1500 to 2000 as the heaviest precip moves onshore. These are expected to rise slightly later tonight everywhere expect Trinity county. This will limit impacts on hwy 101, but confidence is low on how quickly snow levels will rise. Confidence is highest that Trinity county will see significant impacts from the heavy snow, possibly even in Weaverville. The south southeast slopes where strong winds will enhance upslope. This will also help to keep snow levels low. Tuesday is expected to see the rain diminish once the front moves through and before the showers really start to increase in coverage later in the day. Tuesday evening and overnight is when the showers really look to increase and the winds will increase again as well. There is still some disagreement in how quickly this low will move down the coast. In general showers look to taper off through the day on Wednesday. An additional wind advisory may be needed in Humboldt and Del county depending how quickly the surface low fills. Mainly dry conditions are expected with some shortwave ridging in between systems. Friday is expected to some showers, but these are expected to be minimal. Saturday another frontal boundary looks to move onshore, but it will generally be light and snow levels will be over most of the highway passes. Snow levels may drop Sunday as the upper level low potentially drops over the area. && .AVIATION...Ceilings have stayed high near 8 kft today allowing VFR conditions to prevail despite increasing south winds. A front will sweep across the area early this evening, sharply increasing south winds along the coast by 1800. Gusty winds will continue to build this evening reaching as high as 55 mph in exposed areas in Humboldt and Del Norte Counties. Sustained winds as high as 65 mph at 2 kft will lead to widespread low level windshear tonight. Light rain will build in behind the front with ceilings dropping near 4 kft overnight. Brief IFR conditions are likely in showers. Despite the storm, mostly VFR is expected until around 0300 Tuesday morning when MVFR to IFR conditions are possible with falling ceilings and visibilities, especially in stable inland valleys like around UKI. Mostly VFR conditions are expected by late morning Tuesday as ceilings lift and precipitation becomes more showery. Isolated thunder is possible tomorrow right along shore as showers lift over the coastal mountains. /JHW && .MARINE...Strong southerly winds will continue to increase this evening with gale force gusts throughout the waters. Storms force gusts are expected in the northern outer waters with gusts as high as 55 kts. Short period seas will increase with the winds reaching around 14 to 17 feet late tonight. Storm force winds will ease by early Tuesday, though widespread near gale to gale force gusts will continue until early Wednesday morning. Similarly, short period seas up to 15 feet will continue with the wind, mostly in the northern waters. At the same time, a mid period swell around 12 feet at 11 seconds will build in the waters, though current model guidance show it being short lived, totally decaying by the end of the day Wednesday. As the storm system lumber south, gentle north winds will arrive Thursday with seas falling below 6 feet. A weaker system is expected this weekend with moderate to strong southerly winds returning by Saturday. /JHW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Wind Advisory until 5 AM PDT Tuesday for CAZ101-102. Winter Weather Advisory until 5 AM PDT Wednesday for CAZ102. High Wind Warning until 1 AM PDT Tuesday for CAZ103. High Wind Warning until 5 AM PDT Tuesday for CAZ104>106. Winter Storm Warning from 5 PM this afternoon to 5 AM PDT Wednesday for CAZ104>108. Wind Advisory from 5 PM this afternoon to 5 AM PDT Tuesday for CAZ107. Wind Advisory from 6 PM this evening to 5 AM PDT Tuesday for CAZ108>111. Winter Weather Advisory from 5 PM this afternoon to 5 AM PDT Wednesday for CAZ110-111. Wind Advisory from 8 PM this evening to 5 AM PDT Tuesday for CAZ112>115. Winter Weather Advisory from 8 PM this evening to 5 AM PDT Wednesday for CAZ114-115. NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 9 PM PDT Tuesday for PZZ450-455-475. Storm Warning until 3 AM PDT Tuesday for PZZ470. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion
National Weather Service Goodland KS
1003 PM MDT Mon Mar 27 2023 .UPDATE... Issued at 1000 PM MDT Mon Mar 27 2023 While very light snow or occasional flurries may persist for another hour or two.. accumulating snow has ended. As a result, the Winter Weather Advisory has been cancelled. && .SHORT TERM...(This evening through Wednesday Night) Issued at 305 PM MDT Mon Mar 27 2023 At the start of the short term period, the latest RAP analysis shows the CWA with a west-southwesterly flow aloft being under the front part of an upper air trough that has a positively tilted axis just to the west of the CWA. Current surface observations as well as radar imagery shows a surface low slowly traveling across eastern CO allowing with some stronger winds in the southwestern quadrant of the CWA with light to moderate snow continuing in areas along and north of I-70. Forecast models show the axis of the trough passing over the CWA during the evening allowing for a westerly flow aloft. At the surface, the Winter Weather Advisory continues through midnight MDT with the current snowfall continuing. Will monitor this in case an early cancellation is warranted, but chances for snow look to end west to east with the movement of this surface low across the CWA. A Blowing Dust Advisory continues for the southwestern quadrant of the CWA due to the possible stronger wind gusts observed which were around 55 mph that caused some blowing dust within the area. Will monitor this as well in case an early cancellation is needed if conditions improve, but areas that saw lesser snowfall have been reporting some blowing dust visibility reductions. Overnight lows for tonight look to be in the lower teens to the lower 20s with minimum wind chills near the zero degree mark in the far western portions of the CWA. On Tuesday, the front part of a trailing ridge moves over the CWA during the morning hours as the trough departs to the east. A generally west-northwesterly flow is seen over the CWA going into the night as the axis of the ridge stays to the west of the CWA while an upper air low moves over the coast of northern CA overnight. A shortwave disturbance is seen over the CWA during the evening hours as well. At the surface, the southwestern quadrant may be seeing some elevated fire weather concerns during the afternoon hours with minimum RH values in the upper teens. Another surface low is seen in the models in CO allowing for some breezy winds. However, the quicker southerly winds that look to gust up to around 35 kts in southern portions of the CWA look to be during the evening and into the night. Will monitor the timing on these winds in case they start to coincide better with the driest conditions. Daytime highs on Tuesday look to range between the middle 40s and lower 50s while overnight lows are forecasted between the upper teens and upper 20s. For Wednesday, models forecast the ridge moving more eastward with the axis reaching over the CWA during the evening hours giving the CWA a westerly flow aloft. The aforementioned western upper air low is projected to make its way inland behind the ridge as well. At the surface, some models show a cooler airmass moving slightly into the region in the morning with a northeasterly surface flow during this time that turns easterly during the day as models show the CWA between a high out over IA and another low over northern NM. Fire weather does not look to be a concern on Wednesday. Daytime highs look to be between the upper 30s and middle 50s on Wednesday followed by overnight lows in the lower 20s and lower 30s range. .LONG TERM...(Thursday through Monday) Issued at 115 PM MDT Mon Mar 27 2023 Deep trough will be located over the western CONUS to start the period. It will move into the central plains on Friday with a cut off low developing over western Nebraska. Over the weekend will see more of a zonal flow or weak ridging aloft. Early next week, another trough digs into the western CONUS with broad southwesterly flow ahead of it into the plains. Thursday will be windy, warm and dry, with the potential for critical fire weather conditions and perhaps blowing dust south of Interstate 70 in Colorado and Kansas. Highest confidence is in the fire weather, especially south of Highway 40, where humidity will drop below 15 percent. Low to moderate confidence at this time in the wind and blowing dust potential, although furthest south locations stand to see the best chance of both. Lapse rates are supportive of the blowing dust, and forecast soundings show a deeply mixed boundary layer which potentially taps into 40 to 50 mph winds at 2km Thursday afternoon. Highs will be in the 60s and 70s. As the upper low cuts off to the north, the area will initially be dry slotted. However, wraparound precipitation will move into the northern parts of the area late Thursday night and into Friday. Precipitation will be mainly rain showers, but might see a rain/snow mix at times, especially in the morning. Friday will also be breezy with potential for northwest winds gusting up to 40 mph indicated at this time. Temperatures on Friday will cool off into the 40s and 50s. The weekend looks dry under the zonal flow. Temperatures will be slightly above normal on Saturday (60s) and much above normal on Sunday (60s and 70s). With the warmer temperatures will also be fire weather concerns. Humidity does drop to under 20 percent south of Interstate 70 both days. However, wind speeds currently marginal for critical conditions, with gusts under 20 mph forecast. If that continues, may see more elevated fire weather conditions as opposed to critical. A front slips into the area Sunday night with east to southeast surface winds forecast on Monday. Temperatures cool slightly with highs in the 50s and 60s, assuming no clouds. Precipitation chances look to stay west of the area through Monday night. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1000 PM MDT Mon Mar 27 2023 MVFR ceilings and/or visibilities will prevail at the beginning of the TAF period. Improvement to VFR is possible overnight.. though any clearing trend may precipitate fog/stratus development during the pre-dawn hours (08-12Z) Tue morning. VFR conditions and mostly clear skies will prevail thereafter.. through the day on Tuesday. 10-15 knot northerly winds will back to the W and decrease to 7-12 knots overnight becoming variable Tue morning. Winds will shift to the S-SSW and increase to 15-20 knots during the latter portion of the TAF period (~21Z Tue at GLD, closer to 00Z Wed at MCK) as surface high pressure over the region progresses east toward the Central MS River Valley and a surface trough deepens in the lee of the Rockies. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...Vincent SHORT TERM...076 LONG TERM...024 AVIATION...Vincent
Area Forecast Discussion
National Weather Service Gray ME
1047 PM EDT Mon Mar 27 2023 .SYNOPSIS... A low pressure system will bring a mixture of rain and snow tonight, but with little to no wet snow accumulation expected. High pressure builds in Tuesday afternoon into Wednesday with quiet weather. A strong cold front approaches Wednesday night with gusty winds Thursday. && .NEAR TERM /OVERNIGHT/... 1045 PM Update...Quick, minor update to tighten northern edge of PoP further and reduce on the northeastern bound over Maine. Still all rain on surface observations, besides snow up at MWNObs. Overall the forecast remains well on track with little change to running forecast thinking. Dew points in the river valleys have crept above freezing... eliminating accumulation potential for the most part there. However modeled soundings indicate wet accums are still on the table elsewhere, though still keeping the logic that we`ll top out around 1-2" along peaks and ridges. 805 PM Update...More comprehensive forecast update now that the aviation forecast is out the door. Primary edits aside from the usual blending in of obs were to sharpen PoP trends through the remainder of the evening and the overnight period with dry air proving to be more stubborn than prior model runs has indicated. Thus I trimmed PoP along the northern edge of the existing forecast... except at elevation... and boosted PoP a little bit toward the Mass border and into the Sunapee region where better forcing and moisture depth is likely through tonight. At the end of the day however the snowfall forecast remains about the same with light amounts up to 1-2" possible in the higher terrain of southwestern New Hampshire. 640 PM Update...Minor tweaks to T/Td trends. Surface obs still not indicating precipitation reaching the ground in SW NH. Previously... Cirrus continues to spread into the region this afternoon after a gorgeous morning. With high pressure exiting and sfc temps pushing towards the mid 50s across the interior, a light sea breeze has also been observed from mainly Portland south along the NH seacoast. This evening, precip from an approaching low pressure system will onset. With large dewpoint depressions at the surface, don’t expect any measurable precip to begin for a couple more hours. Rain is expected initially, with snow mixing in first across higher elevations of NH. Lower elevations won’t see snow mix until precip rates pick up and sun goes down. Monitoring a snowband tool, there are some low chances of deformation precip bringing steadier rates of snow near the NH/MA border late evening and around midnight. Continuing to mention very light accumulations due to warm ground and low snow ratios, with perhaps an inch at higher elevations of southern and central NH. Visibility may be more impactful if snow rates do perform well. North of this area, precip should be fairly light. The mix of rain/snow may also be more widespread as rates elsewhere may not allow as much dynamic cooling. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... All precipitation should lose intensity come early Tuesday morning. Just a slight trough will remain in wake of the low, allowing some spotty rain showers to continue near the coast and interior. Tuesday AM will be in stark contrast to this morning, where it should be fairly damp and cooler through the morning. Temp trends do warm up, but it should run a couple degrees off normal for the day, remaining mostly cloudy. With remaining moisture and the heating, could see a few air mass rain showers develop in the afternoon. But these will be largely driven by steep low level lapse rates which aren’t too high confidence at this point. The better chance for these may be where breaks in clouds develop...with the HRRR suggesting near central ME and portions of the interior to SE NH. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Generally quiet weather for Wednesday with seasonable temperatures from the mid 30s over the higher terrain, to 40s and some low 50s south. Wednesday night lows will drop into the low to mid 20s for the higher terrain, and into the mid and upper 20s elsewhere. Attention turns to a strong arctic cold front and associated low tracking east across Quebec and the Great Lakes. The feature will retrograde back towards the Hudson Bay, so precipitation will not be noteworthy locally. There will be an uptick in precip that develops along the front as it crosses the area late Wednesday night into Thursday. The precip will be primarily snow especially as temps drop behind the front. No accumulations expected. The main impact from this front will be an uptick in winds as cold air advection supports deep mixing with gusts 30 mph or greater, higher in the mountains. Temps will rebound on Friday as we see returned flow. Meanwhile, a larger storm system will move out of the Rockies ahead of a mid- level low and trough. The surface feature will become better organized as it moves east on Friday with moisture streaming into the area Friday night. Snow and rain showers will increase with the fropa, and as the sfc low approaches the area the showers will continue to fill in. Steadier rain will transition to showers Saturday afternoon, and then taper off on Saturday night as snow. The track of the system will influence the wind magnitude and temp advection, with the region firmly in the warm sector limiting the snowfall potential. Should have a better idea on magnitude as we approach the end of the week. Cold front will trail behind the system with dry conditions Sunday. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... Short Term...VFR conditions this afternoon will lower to IFR across southern NH late this evening and overnight. SN/RA mix will move across the region tonight, with a few showers remaining Tuesday morning. AUG/RKD may escape some of the lower restrictions as vis and cig impacts remain to terminals south. Tuesday will see MVFR conditions remain during the morning, and trend VFR in the afternoon. N to NW wind will carry a few more gusts than Monday. VFR also expected Tuesday night. Long Term...Non-VFR possible with a cold front Wednesday night/Thursday. && .MARINE... Short Term...Below SCA criteria conditions as low pressure passes well south of the waters this evening and overnight. Will see rain/snow move across the area, with some visibility restrictions possible. Waves remain mainly 1-2 feet. Long Term...Conditions will be favorable on Wednesday but the passage of a strong cold front early Thursday will introduce small craft conditions to the waters, with gusts to gale force possible. Some improvement by weeks end as the gradient relaxes Friday allowing winds to subside. However, another storm system expected to impact the coastal waters this weekend, though there remains much uncertainty on the track and subsequent wind magnitude. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ UPDATE...Casey NEAR/SHORT TERM...Cornwell LONG TERM...Jamison

.SYNOPSIS... Issued at 357 PM CDT Mon Mar 27 2023 Key Messages: - Several inches of snow expected this afternoon and evening across southwest Nebraska into the western Sandhills. - Winter Storm Warnings and Winter Weather Advisories are in effect through this evening portions of the western Sandhills and southwest. - The potential for another system with accumulating snow mainly across north central Nebraska Thursday night through Friday. Convectively enhanced snowfall continues to develop across portions of far southeast Cherry, Garden, Grant, Arthur, McPherson into Keith County. This area from the latest HRRR and RAP mesoscale models indicates 200-400 J/KG of elevated instability exists in this area. A more widespread light to moderate snow along and south of Interstate 80. && .SHORT TERM...(This evening through Tuesday night) Issued at 357 PM CDT Mon Mar 27 2023 As an upper level trof currently located over southwest Nebraska into far northwest Kansas with a surface low in the Texas panhandle. Synoptic forcing with this system will be fairly strong with an area of strong frontogenesis along the western side of the H7 low late this afternoon and evening. The latest RAP model shows elevated instability from 200-400 J/KG focused across portions of Garden, Arthur, and Keith County. This convectively driven/enhanced area of snow will be aligned along the deformation axis. Given steep lapse rates and instability some thundersnow certainly seems possible, particularly within the deformation zone from southwest Nebraska up through the western Sandhills. Snow accumulations were increased in line with an HRRR and RAP blend through this evening. With these model showing some consistency, snowfall amounts from 5 to 10 inches are forecast over eastern Garden, Arthur into Keith County. These counties are now upgraded to a Winter Storm Warning. Heavy snow with visibilities of a quarter mile or less can be expected, with snowfall rates up to 2 inches per hour. Across the counties under the Winter Weather Advisory, 3 to 5 inches of snowfall are expected. locally higher amounts are possible. A tight gradient in accumulations on the eastward side from Mullen through North Platte and Brady, where less than an inch is expected and none further east. Snow diminishes after 03Z with northerly winds into this evening mainly from 5 to 15 mph, so blowing and drifting will be minor. Some clearing after midnight tonight, with lows from 15 to 20. Expect quiet weather tomorrow with a return of afternoon sunshine. Temperatures will be warmer but still below normal as highs range from the lower 40s across southwest Nebraska to around 50 further to the northeast. Winds will be westerly at 10 to 20 mph. .LONG TERM...(Wednesday through Monday) Issued at 357 PM CDT Mon Mar 27 2023 Medium range models including the GFS and ECMWF depict a progressive pattern with some upper ridging building over the region Wednesday night into Thursday. This will keep the region dry, yet cool in the 30s on Wednesday behind a cold front and dry and much warmer on Thursday with highs upper 50s to upper 60s. A change by Thursday night as a deep upper trof moves through the Rockies and Four Corners Region drives a strong cold front through western Nebraska. This will drop temperatures significantly and combine with increasing chances for precipitation to bring snow back to Nebraska Thursday night into Friday. Ensemble QPF plumes continue to show considerable spread so there remains a good degree of uncertainty with this system late next week, but probabilistic guidance currently indicates the most likely locations to see impactful snow accumulations will be mainly north of highway 2. Expect this forecast to change in the days ahead as new guidance becomes available. Behind this system upper ridging brings warmer and generally dry conditions to the area for next weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 623 PM CDT Mon Mar 27 2023 Snow along with areas of MVFR/IFR will continue across the western Sandhills into southwest Nebraska through tonight (impacting KIML, KOGA, and KLBF terminals). Snow will gradually taper off around midnight brining a return to VFR conditions through the end of the TAF period. Winds will remain light overnight at generally 5kts or less. These winds will shift towards the west/southwest in the morning before increasing for a brief period in the afternoon with gusts up to 20kt possible. && .LBF WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until midnight MDT tonight for NEZ022-035- 057. Winter Weather Advisory until 1 AM CDT /midnight MDT/ Tuesday for NEZ023-024-036-056-058-059-069>071-094. && $$ SYNOPSIS...Roberg SHORT TERM...Roberg LONG TERM...Roberg AVIATION...Viken
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1014 PM EDT Mon Mar 27 2023 .SYNOPSIS... A cold front moves through tonight. Low pressure will pass well offshore Tuesday night, with an upper shortwave bringing showers. High pressure then builds in from the north and west Wednesday and Thursday, before sliding offshore Friday. The next frontal system will impact the area over the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... As of 1010 PM Mon...Frontal boundary has gotten a bit hung up across the Piedmont of NC but has steady advanced southward across VA, driving a small complex of showers and storms around the Williamsburg area. The HRRR shows this complex gradually easing southeastward towards OBX, but this same model has been too aggressive with convective coverage most of the day. Could see some light decaying showers move over the area and maintained PoPs for that scenario. Otherwise, rest of the forecast is on track. Prev disc...A deepening area of low pressure will push off the Delmarva Peninsula later this afternoon with the trailing cold front pushing across the area this evening. Despite some instability and available shear in place, very scant moisture and weak lapse rates will prohibit vigorous TS development. Can`t rule out an iso shower or storm early this evening, and if one does form, it will be mainly along/N of Hwy 64. Temps remain mild tonight with only weak CAA behind the front, with lows generally in the 50s expected. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... As of 303 PM Mon...Quiet conditions expected with transitory high in place before next system moves in. Highs will be seasonably mild, generally around 70 S and W with upper 50s OBX. Skies partly cloudy with light E to NE flow. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... As of 245 AM Mon...Unsettled weather Tuesday and Tuesday night will be followed by a pleasant string of days mid to late week. The next frontal system will impact the area next weekend, though the precip characteristics of this front remain uncertain. Tuesday night and Wednesday... Low amplitude H5 trough moves over the eastern US, with an embedded shortwave near the base of the trough crossing the area Tuesday night into Wednesday. Falling heights aloft will prompt the development of a wave within the front well offshore, with increasing NE flow bringing in a cooler maritime airmass. While overall moisture will be limited, upper dynamics should be sufficient to squeeze at least scattered showers out of the airmass Tuesday night into Wednesday morning. Overall QPF will be low, only a few tenths of an inch at most, but there is an increasing signal that much of the area will see at least a little rainfall before sunrise Wednesday. Skies gradually clear midday through the afternoon Wednesday, but persistent CAA will keep temps well below normal. Wednesday night through Friday...General H5 height rises begin later Wednesday and continue through the second half of the workweek, with the upper ridging reaching its strongest later Friday. At the surface, high pressure builds overhead Wednesday night into Thursday, then is reinforced by stronger high pressure building in from the Great Lakes region Thursday night. This high moves offshore Friday, with surface return flow/WAA developing in through the day. Dry conditions and ample sunshine prevails through these several days, with temps trending back to normal Thursday, then well above normal for Friday. Saturday through early next week...Height falls ensue once again next weekend as upper troughing moves over the eastern US. Associated strong surface low lifts across the Great Lakes next weekend, with the associated warm front possibly lifting through ENC Friday night/Sat AM, anchoring our area within the warm sector until cold frontal passage Sunday AM. Pre-frontal flow Saturday/Saturday night currently looks to have a strong westerly component, which is often an indicator of a moisture starved front (a characteristic that the global models can be slow to latch on to), and have limited POPs to low end chance accordingly. Still, this period will require monitoring for convective potential given the well above normal temps and a lifting mechanism (cold front). High pressure builds in from the south and west in the wake of the cold front later Sunday into early next week, with moderating temps and mainly dry conditions. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... SHORT TERM /through 00Z Wed/... As of 730 PM Mon...High confidence in VFR conditions through the period. Weak front, currently over the Piedmont, is expected to begin crossing the region from the northwest after 04z. Some guidance is quite aggressive with shower and tstorm development along the boundary tonight, but lack of appreciable deep moisture pokes a hole in this idea and maintained a dry forecast. Behind the front, light N to NE winds are expected, then veering easterly at the end of the period. LONG TERM /Tuesday through Saturday/... As of 3 AM Mon...Tuesday night brings the next chance of sub VFR flight cats as at least scattered showers cross the area under a passing shortwave. Later Wednesday through Friday brings high pressure building in with relatively light winds and VFR conditions. A frontal system this weekend could bring gusty winds and shower/storm chances beginning later Friday through Saturday. && .MARINE... SHORT TERM /through Tue/... As of 303 PM Mon...Swrly gradient inc a bit late this afternoon and marginal SCA cont for ctrl/srn waters S of Oregon Inlet. Seas may build to 6 ft esp Ocracoke to Oregon Inlet leg. A cold front will push across the waters overnight with a nly surge keeping SCA winds in place for ctrl portions of the waters. LONG TERM /Tuesday night through Saturday/... As of 2 PM Mon...Low pressure developing offshore and high pressure inland will bring breezy to strong N to NE winds Tuesday night into Wednesday, with SCAs likely needed. Latest guidance has trended a bit stronger with the NNE surge Wed morning (HRRR and NAM in particular). There is potential for a few hours of gale force winds, mainly south of Hatteras, between 8-12z. Will go ahead with SCAs for the Pamlico Sound and Neuse River...which will need to be expanded to the coastal waters, and possibly the northern sounds, when current SCAs expire. High pressure builds overhead later Wednesday through Friday morning, with mainly light to moderate winds, and minimal marine hazards expected. The next stronger frontal system will impact the area late Friday through the weekend, with current guidance suggesting a prolonged period of gusty SW winds later Friday/Friday night through Saturday night, with solid SCA conditions expected, and gale force winds possible. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Small Craft Advisory from 2 AM to 4 PM EDT Wednesday for AMZ135. Small Craft Advisory from 2 AM to 2 PM EDT Wednesday for AMZ137. Small Craft Advisory until 6 AM EDT Tuesday for AMZ152-154. && $$ SYNOPSIS...MHX NEAR TERM...TL/MS SHORT TERM...TL LONG TERM...CQD/CB AVIATION...CB/MS MARINE...TL/CB
Area Forecast Discussion
National Weather Service Raleigh NC
735 PM EDT Mon Mar 27 2023 .SYNOPSIS... A cold front will move southeast across the Carolinas tonight. A mid and upper-level disturbance will cross the region late Tuesday and Tuesday night. && .NEAR TERM /THROUGH TONIGHT/... As of 735 PM Monday... Central NC continues to be under the influence of strong SW flow aloft between a mid-level disturbance currently over the eastern Great Lakes/northern Mid-Atlantic and a subtropical ridge over the Caribbean. At the surface, a 1010 mb area of low pressure is currently centered over western VA, which will continue to move east and offshore the Delmarva coast this evening. As it does so, it will drag a prefrontal trough and cold front through central NC the rest of this afternoon and this evening. The cold front is currently located just west of the Triad, where dew points quickly dropping into the 40s are now being observed, and the warm front has pushed north into central VA. Thus all of central NC is still in the warm sector, and dew points in the lower-to-mid-60s are being observed. Skies have become partly cloudy for most of our region outside of the far SE, so temperatures have warmed into the mid-to-upper-70s. This has allowed MLCAPE to increase to as high as 1000 J/kg over the western Piedmont according to latest SPC mesoanalysis, and latest RAP forecasts have it continuing to increase to 1000-1500 J/kg across much of central NC from now through early evening. Steep low- level lapse rates (7-9 C/km) are also being observed in the NW Piedmont, but the best mid-level lapse rates are over southern and eastern portions of central NC. Temperatures aloft are fairly warm and there is considerable dry air aloft at and above 700 mb. In addition, there is a lack of large-scale upper forcing for ascent. Despite these limiting factors, a line of showers and isolated storms has already begun to develop along the cold front and prefrontal trough, and it is currently pushing SE over the Triad. The line will push SE through the rest of central NC over the next several hours. Effective bulk shear is quite impressive, as high as 70 kts over the NW Piedmont, so if any updrafts are able to get high enough, some hail will be possible, which looks to be the main threat. Given there is less instability in our far southeastern counties where widespread cloud cover stayed around longer today, and given the timing of the line not getting there until after dark, the threat is lower there. The line will diminish and exit the Coastal Plain after about 03z. Winds will shift to the NW and N behind the cold frontal passage, and skies will clear, before more high clouds move in overnight from the west ahead of the next mid- level disturbance. Thus increased forecast low temperatures a bit, in the upper-40s to mid-50s. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 315 PM Monday... Behind the cold fropa, cold/dry advection is expected to briefly continue through the early morning hours as the front continues to sag south over the Southeast before stalling in a west/east orientation extending from the SC coast to just north of the central Gulf coast states. A 120-150kt upper level jet streak over the OH Valley extending into the lower MS Valley will sag slightly southeast and strengthen as a shortwave over the Mid MS Valley shifts ESE into the lower OH Valley by 00z. This will position the southern Mid-Atlantic within the optimal location underneath the right-entrance-region of the upper jet, strengthening mid-level flow, and glancing DPVA to lead to excellent upper level support for upward motion. As this upper forcing approaches the Mid-Atlantic and the Southeast, a weak wave of low pressure is expected to develop over the Gulf Coast along the remnant baroclinic boundary from the fropa mentioned above. This area of low pressure should track northeast into the Carolinas by 00z, coincident with the best upper forcing. As the low approaches, 700mb WAA maximizes along with low- level FGEN support at 925-850mb within the deformation zone to blossom precipitation directly over central NC Tuesday evening. Significant drying at 500mb will likely be punching into central NC ahead of the shortwave, but deep saturation below this layer co- located with ample multi-layer ascent should sustain precipitation over central NC for roughly a 6-8 hour period until the shortwave pushes through the area late Tuesday night and promotes deep layer subsidence in its wake. A broad area of 1027mb high pressure will shift into the OH Valley by early Wednesday morning promoting a secondary, reinforcing fropa leading to 6-8mb surface pressure rises into Wednesday morning. CAA should lead to a well mixed boundary layer overnight and may promote wind gusts up to 25 mph over the Sandhills and southern Coastal Plain between 2AM and 8AM. Precipitation totals range from a tenth of an inch across the southern tier to up to a third of an inch across the northern Piedmont into the central/northern Coastal Plain were the best overlap of deep layer forcing exists. A pencil thin layer of orographic cirrus near the Triad extending up into VA should be present early Tuesday morning with very thin cirrus elsewhere. Upper level cloudiness within the moist upper level flow should thicken and lower through the day, tempering temperatures a bit during the afternoon with forecast highs peaking in the low/mid 60s (N) to low 70s (S). Lows will largely be driven by CAA behind the reinforcing fropa and expected to bottom out in the 40s with upper 30s possible in the coldest spots. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 230 PM Monday... Wed-Fri AM: Upper ridging will slowly build east from the Rockies on Wednesday to across the Carolinas by Friday. While the upper ridge builds in, surface high pressure will build east from the Mid- Mississippi River Valley Wednesday to across the Carolinas Wednesday night and offshore Thursday. Another surface high will build from the northern Plains Wednesday to the Ohio Valley Thursday and off the Mid-Atlantic Coast by early Friday. These features will maintain dry weather across central NC through early Friday. Highs will increase from 5 degrees below normal on Wednesday to around 10 degrees by normal on Friday as subsidence increases across the region. Slightly below normal lows Wednesday will increase to just above normal by Friday morning. Fri PM-Sat PM: As the surface ridge moves offshore, a prefrontal trough may approach the region Friday afternoon, increasing chances for showers from NW to SE throughout the day and night. By Saturday, a cold front will approach from the west, and an upper trough will swing east from the TN Valley to NC by Saturday night. These features will provide a better chance of precipitation compared to Friday. Additionally, strong low-level and deep-level shear, along with weak instability, could generate thunderstorms across the region, with the best chances closer to the Coastal Plain where surface dewpoints in the low 60s remain. Winds will increase through the period, and especially Saturday as a lower-level jet moves into the area and pressure gradients increase. SW wind gusts could be as strong as 30-40 mph on Saturday, then begin to diminish Saturday night behind the front. Widespread mid-70s to low 80s are expected for highs, with lows around 60, which is around 20 degrees above normal. Sun-Mon: Surface high pressure then builds east from the Midwest Saturday to the Mid-Atlantic Sunday and off the coast around Monday. At the same time, weak upper ridging returns as it builds in from the west and will help keep conditions dry to start the next week. Cold air advection behind Saturday`s front will help lower highs to the 60s and 70s Sunday, then increasing subsidence and warm air advection Monday increase highs to the 70s area-wide. && .AVIATION /00Z MONDAY THROUGH SATURDAY/... As of 800 PM Monday... Although there are still a few showers across the region, all sites are currently VFR and expected to stay VFR through the night, unless a stray shower passes over a terminal. The front is currently still west of the NW Piedmont. As it moves through the region, expect a wind change overnight from southwesterly to northerly by early morning. Northerly winds will continue for most of the day Tuesday with another round of sub-VFR conditions possible near the end of the TAF period. Outlook: The approach and passage of a mid/upper-level disturbance will result in a chance of rain and sub-VFR restrictions Tue night. After a period of dry weather from Wednesday through Friday, a cold front will bring another chance of showers/storms and sub-VFR restrictions on Saturday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...CA/MWS NEAR TERM...Green SHORT TERM...Swiggett LONG TERM...JJT AVIATION...CA/MWS