Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/17/22

Area Forecast Discussion
National Weather Service Denver/Boulder CO
831 PM MDT Sat Apr 16 2022 .UPDATE... Issued at 830 PM MDT Sat Apr 16 2022 The main update was to increase wind gusts during the day tomorrow at the base of the foothills and adjacent plains. Model cross sections continue to show the development of a mountain wave with strong winds spreading throughout the foothills. Flow in the 600-500 mb level doesn`t fully turn easterly but it reverses enough that the development of a mountain wave seems likely. The HRRR has consistently been showing the potential for wind gusts up to 60 mph in Jefferson and Boulder Counties. When you combine that with expected minimum relative humidities in the teens, there was enough concern about critical fire weather conditions that the Red Flag Warning was extended to zone 239 (eastern Jefferson and Boulder Counties). The rest of the fire weather highlights were left the same since there is some uncertainty about minimum relative humidity across the northeast plains. Otherwise, there is a shortwave trough over northern Utah with a plume of upper level moisture ahead of it entering norther Colorado. This is still on track to bring 2 to 6 inches of snow to the higher mountain ridges tonight and tomorrow. PoPs were modified a bit to better align with the trough passage. The plains may see a few showers near midnight but they shouldn`t amount to much. && .SHORT TERM...(This evening through Sunday) Issued at 203 PM MDT Sat Apr 16 2022 Multiple weather elements occurring tonight into Sunday so will organize from West to East. Over the higher terrain the zonal ridging overhead will give way to more southwesterly upper level flow with the trough that is pushing into central California. The accompanying jet will split and round the base of the trough and into the region tonight into Sunday. Moisture will increase with this feature and combine with orographics initially to bring light snow showers to the Park and Gore ranges by late this afternoon. Lapse rates will improve with the proximity of the left exit region of the upper jet and associated vort max to increase coverage of showers through the northern and central mountains and even introduce the possibility of a rumble of thunder this evening. Current amount projections of 2 to 6 inches is on track by late Sunday when the trough passes through and moisture diminishes. Slightly further east in the foothills, model cross sections show the development of a mountain wave during the early morning hours. Cross mountain flow increases with upwards of 60kts by midnight and 50 to 55 kts through the day tomorrow. This could equate to wind gusts up to 65 mph by sunrise and 55 to 60 mph through the day over the higher peaks. There is some concern for high winds along the foothills however, the question remains how strong the mountain wave will be given the abundance of upstream moisture and instability provided by the aforementioned jet. The strength of the amplification will mean the difference between 45 mph and 65 mph for some foothill areas. Even further east on the plains conditions will be party cloudy with highs reaching into the upper 60s with downslope winds and warm air advection. Wind gusts will range from 30 to 35 mph with 40 to 50 mph gusts over the northern plains. Relative humidity values will range from the teens into the lower 20s with elevated to critical fire weather conditions possible. See the fire weather section for more information. .LONG TERM...(Sunday night through Saturday) Issued at 203 PM MDT Sat Apr 16 2022 Upper level high pressure will dominate the Rocky Mountain Region through much of the work week with mostly dry and breezy conditions and above normal temperatures expected. Tuesday and Friday look to be the warmest and driest days of the week, especially east of the mountains, due to downsloping flow. Both of these days should see max temperatures on the plains climbing into the mid 70s to lower 80s. A quick moving upper level disturbance glancing Colorado to the north may bring scattered light snow showers to the high country Tuesday night into Wednesday morning with light accumulation over the higher peaks. Cooler unsettled weather is expected late Friday and Saturday as a larger upper level trough moves across the region. At this time, there is quite a bit of uncertainty due to run to run inconsistencies and model discrepancies. Latest model trends are suggesting this system may take a similar track to the previous one that produced blizzard conditions across North Dakota. One thing that is pretty certain is that it will be cooler with a good chance for rain and snow showers in the high country and breezy conditions on the plains. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 538 PM MDT Sat Apr 16 2022 Gusty southeast winds have developed late this afternoon after a boundary moved through. These southeast winds are expected to increase in speed this evening with gusts up to 36 knots. There are multiple areas of blowing dust in Arapahoe County that may move near the airport and reduce visibility. ILS landings seem possible as long as the strong winds continue. By the late evening, wind speeds will begin to decrease towards typical drainage patterns. Winds weaken during the early morning hours before strong westerly winds develop by the late morning and last through the afternoon. The best guess for the development of the westerly winds is between 16-18Z. && .FIRE WEATHER... Issued at 203 PM MDT Sat Apr 16 2022 Another day of elevated to critical fire weather conditions for Sunday. Winds will increase during the early morning and continue through the day with gusts from 25 to 35 mph over the eastern plains. At this time there is varied confidence on where the critical fire weather conditions will exist due to RH levels. There is lower confidence with areas along and north of I-76 where slightly higher RH forms, however, that is also where the higher winds will be. Further south the winds will be slightly lower but the conditions will be drier. Went ahead and upgraded the Fire Weather Watch to a Red Flag Warning for zones 240, 241, 245, 245, and 247 from noon to 8 pm tomorrow given the low RH values and dry conditions in these areas. Will continue to monitor model trends for areas north but it is important to note that even areas outside the warning area can be susceptible to fire spread given current conditions. Dry and breezy weather along with above normal temperatures will continue Monday through Friday with elevated to critical fire weather conditions expected across the plains, Palmer Divide and portions of the foothills. At this time, the greatest fire weather concern appears to be on Tuesday and again on Friday due to very warm temperatures (70s to lower 80s on the plains), low relative humidity (10 to 15 percent in the afternoon) and wind gusts to 30 mph. As a result, more fire weather highlights seem likely later this week. && .BOU WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Sunday afternoon through Sunday evening for COZ242>244-248>251. Red Flag Warning from noon to 8 PM MDT Sunday for COZ239>241- 245>247. && $$ UPDATE...Danielson SHORT TERM...Bowen LONG TERM...jk AVIATION...Danielson FIRE WEATHER...Bowen/jk
Area Forecast Discussion
National Weather Service Columbia SC
804 PM EDT Sat Apr 16 2022 .SYNOPSIS... Measurable rainfall through the evening is unlikely. A front will move across the area late tonight setting up unsettled weather for Sunday and Monday. Showers and thunderstorms are possible across the southern forecast area Sunday morning and afternoon before widespread rain moves into the area. 1-2" of rain is possible Sunday night and Monday morning, followed by cold air damming conditions Monday afternoon. Much drier air fills in for the rest of the week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Westerly winds and drying mid-levels will hinder moist convection through the evening. We can`t rule out an isolated shower/sprinkle as a weak shortwave moves over the FA but measurable rainfall appears unlikely for most of the FA this evening. A cold front will move into the Upstate SC then push slowly southeast through the area overnight. By morning the front may hang up in the southeast Midlands and CSRA. The high resolution CAMS suggest at least a slight chance of a shower along the front during the early morning hours. HRRR and lamp suggest low clouds may form near the front toward daybreak and possible fog. Guidance low temps consistent in the mid 50s to low 60s. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... Summary: Showers and thunderstorms, with some gusty winds and small hail possible, are expected across the southern forecast area Sunday. More widespread rain develops late Sunday into Monday as a CAD wedge develops. Heavy rain likely with 1-2" possible for much of the area. Moderate-high confidence in the overall forecast, including CAD conditions Monday. By 12z Sunday, a weak cold front will be crossing the forecast area with strong dew point gradient from north to south. Showers and an isolated thunderstorm are possible to linger along the front throughout Sunday morning with some weak elevated CAPE in place. These should remain south of the boundary, primarily in the CSRA and extreme southern Midlands; hi-res guidance supports this but overall coverage is somewhat uncertain. For now, continued with chance PoPs across the southern forecast area with slight chance for thunderstorms through 18z. Thunderstorm chances increase in the CSRA and southern Midlands in the afternoon with high temperatures climbing into the 70`s and dew points remaining in the 50`s. CAPE will remain fairly limited in the afternoon, but dry air aloft and shear profiles suggest a subtle severe risk. Across the northern forecast area, dew points will fall into the 40`s and the chance of rain will remain slight or less through mid-afternoon. A strengthening surface ridge will begin to entrench itself along the east coast by late Sunday afternoon. 850mb flow will swing to out of the southeast, producing a broad shield of strong isentropic lift across the region with the surface boundary still in place. With PWATs still in the 1.25-1.5" range, this is a prime setup for a widespread heavy rain threat; WPC has issued a marginal risk for excessive rainfall for the entire area and a slight risk in the CSRA. Both hi-res and global ensembles are consistent in producing 1- 2" of rain across the entire area, mainly in the 00z - 12z Sunday into Monday window. This rainfall will help reinforce the surface ridging lee of Appalachians and produce a fairly strong CAD event for Monday even behind the heaviest precip. High temps Monday will likely remain in the 40`s across the northern Midlands and, depending where the wedge front develops, in the low 60`s in the CSRA. Rain chances quickly fall Monday afternoon as dry air moves in aloft as a low pressure develops along the coast, but low cloud cover and drizzle will likely remain through Tuesday morning as the low reinforces low level advection. Overnight lows Monday will not move much, in the mid 40`s. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As the surface high and coastal low exit Monday night into Tuesday, strong dry advection set in with PWATs crashing below 0.25" by Tuesday morning. Any remnants of the wedge should quickly mix out consequently and high pressure will dominate the long term. There is good agreement across global ensembles in this overall pattern with below average temperatures Tuesday and Wednesday, then steadily warming and dry throughout the week as anomalously strong high pressure settles off the southeast US coast. The only feature of note is a possible frost Wednesday morning as the high settles overhead. NBM mean currently keeps morning lows around 40 but a 10th percentile in the low 30`s. Given the forecasted strength and dryness of the high, if the high does settle overhead, a frost is probable but predictability is still too low at this range. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Restrictions expected on and off through the valid TAF period... VFR conditions through the first part of the tonight with MVFR to IFR CIGS/VSBYS redeveloping mainly after 17/09Z. Confidence in fog threat appears highest at AGS and DNL near 17/12z, though lesser reductions may occur at the other TAF sites. A few -SHRA are possible in the morning near a frontal boundary as a mid level trough moves through the area, but confidence not high enough to include in TAFs. Conditions slow to improve back to VFR with limited mixing after 17/14z, before deteriorating again Sunday afternoon ahead of the next system. VCSH possible particularly at AGS/DNL after 17/21Z. EXTENDED AVIATION OUTLOOK...Ceiling and visibility restrictions expected to continue Sunday night into Monday as cold air damming develops. This will result in widespread rain/low ceilings and visibility restrictions, especially Monday. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Des Moines IA
836 PM CDT Sat Apr 16 2022 .UPDATE... Issued at 834 PM CDT Sat Apr 16 2022 There is growing concern about snow accumulations tomorrow. Have nudged snow amounts up slightly from northwest of Des Moines into northwest Iowa to get more widespread amounts 1"+ per recent RAP, NAM, and HRRR QPF. Confidence in amounts is low with mid April solar insolation and ground temps, and marginal temp/dewpoint/wetbulbs all in play, but it at least seems to be heading in the right direction. If rates get too high in the morning, a few inches of snow are possible on vegetation. Any snow should diminish later in the afternoon however due to warming low level temps and/or the lack of ice introduction. && .DISCUSSION.../Tonight through Saturday/ Issued at 250 PM CDT Sat Apr 16 2022 Forecast Highlights: --Breezy the rest of the afternoon. --Light rain/snow Sunday. --Breezy again to start the new work week. --Additional precipitation chances midweek. TODAY: A cool but mostly sunny day continues across much of the state as a Canadian high pressure moves southeast through the Upper Midwest into tonight. A deep low pressure over the Great Lakes region did bring some clouds into northern Iowa this morning, as could be seen on GOES-16 water vapor imagery, and, along with the approaching high pressure, created a tightened pressure gradient across the area. As a result, winds have been breezy today with sustained winds out of the northwest between 10 and 20 mph and gusts up to 35 mph. As alluded to, temperatures remain cool with afternoon temperatures mainly in the 40s. TONIGHT THROUGH SUNDAY: The breezy winds are expected to subside into this evening and become out of the east as the aforementioned high pressure passes to the east of the state and into the Great Lakes region. As this happens, a low pressure moves into the Plains from the Mountain West bringing rain and snow to Nebraska and the Dakotas overnight and arriving on our doorstep early Sunday morning. Cloud cover is expected to stream in this evening ahead of the approaching system which will help keep low temperatures slightly warmer than this morning, but temperatures will still be below freezing across the north half or so of the area. Thus, as precipitation starts Sunday morning, the precipitation type will likely be light snow across northern Iowa with a light rain/snow mix quickly becoming all rain in the south. Forecast soundings do suggest any precipitation will initially have to overcome low to mid- level dry air which will both delay precipitation onset as well as generally lessen any accumulating snow across the north. As the profile cools and saturates, precipitation will begin to reach the ground and with plenty of ice introduction aloft, have kept some snow in the forecast across the north as temperatures look to remain cool enough to support snow at least initially. As temperatures warm on Sunday, precipitation will become all rain through the afternoon, though a rain/snow mix may linger in the north into midday. Snow accumulations in the north Sunday morning, if any, will be light, generally under 1 inch, and will be limited to grassy surfaces. High temperatures on Sunday will once again be in the 40s. SUNDAY NIGHT/MONDAY: There could be some additional light snow Sunday evening in the north as temperatures decrease below freezing again but this would likely be very limited in coverage and no snow accumulations are expected Sunday night. Precipitation ends late Sunday night/the early morning hours Monday as the system pushes east. Northwest flow behind the departing low/associated cold front will reinforce our cooler temperatures and increase winds Sunday night into Monday. Have boosted winds accordingly through the day Monday with forecast soundings suggesting 30-35+ knot winds through the mixed layer by the afternoon. Temperatures remain similar to the weekend with lows in the mid 20s to low 30s and highs in the 40s to low 50s. BEYOND MONDAY: The forecast into mid next week brings increasing chances for precipitation with another low moving through the Midwest as well as the return of some warmer air. Details with the midweek system are still being refined. The flow does look to become southerly late Tuesday into Wednesday which will help usher in some warm air advection and thus boost temperatures into the 60s on Wednesday and Thursday. && .AVIATION.../For the 00Z TAFS through 00Z Sunday evening/ Issued at 711 PM CDT Sat Apr 16 2022 Clouds should increase into the night with lowering ceilings but conditions should remain VFR through Sunday morning. Precipitation will develop later in the day however, initially light snow, but then transition to either a mix or entirely light rain. As this occurs, confidence in MVFR conditions should increase later in the day as visibilities and ceilings both decrease. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Small DISCUSSION...KCM AVIATION...Small
Area Forecast Discussion
National Weather Service Goodland KS
517 PM MDT Sat Apr 16 2022 .SHORT TERM...(This evening through Tuesday morning) Issued at 238 PM MDT Sat Apr 16 2022 Weak ridging over the plains is being observed on the latest RAP analysis with partly cloudy skies over the area. Similar to yesterday temperatures are struggling to warm as an easterly component to the wind continues to advect a slightly cooler airmass into the region. As a result, similar to yesterday, a blend of the RAP and HRRR was used to pick up on the cooler temperatures. Weak shortwaves are visible on the 500 mb and 700 mb level on SPC mesoanalysis. These shortwaves are expected to bring an increase in cloud cover along with the potential for some sprinkles over the northern and eastern counties to occur throughout the overnight hours if enough low level moistening can occur. Moisture is expected to increase from the SSE in the form of low stratus. Temperatures were raised east of the Kansas/Colorado state line, as the strong moisture advection is currently not expected to impact east Colorado at this time, to account for the low clouds to limit the overall amount of radiational cooling. Low temperatures are expected to be from the upper 20s/low 30s across east Colorado to the mid to upper 30s along and east of roughly Kansas Highway 27. A upper level trough is expected to move across the area with a surface low developing across the Dakotas. As the trough moves by an abrupt wind shift to the NW will occur along with an increase in winds as gusts up to 35 mph are expected. Drier air will filter in behind the trough allowing RH values to plummet through late morning and afternoon hours, with the driest air currently expected across the northern counties. As a result a Fire Weather Watch has been issued for the afternoon hours for counties along and north of Highway 36 from Yuma County through Decatur County. The above mentioned wind shift and gusty winds behind will have the potential to create dangerous and unpredictable wildfire spread. The counties not within the watch will still have the potential for unpredictable wildfire spread with the wind shift despite RH values currently not forecasted to fall to critical criteria. A caveat that may hinder how dry the area is and as a result the duration of fire weather tomorrow is a mountain wave creating mid level cloud cover during the afternoon hours with LCL`s around 6000 feet according to forecast soundings. Irregardless if the cloud cover solution does come to fruition, the area within the Fire Weather Watch is extremely dry with a recent D3 drought addition added to Hitchcock, Red Willow, Rawlins and Decatur counties in the latest drought monitor update. High temperatures for Sunday will be warmer as highs are currently forecasted to be in the mid 60s to low 70s due to the northwesterly flow downsloping component. Sunday night, cloud cover is expected to continue before moving out west to east after 09Z, overnight low temperatures will be highly dependent on the speed of the departure of the cloud cover. Overnight lows are currently forecasted in the upper 20s to mid 30s from west to east. Monday, an upper level ridge again moves over the area with a similar pattern to what has occurred yesterday and today as southeasterly winds return to the area. As a result high temperatures will again make a return to the upper 40s to 50s with mainly clear skies currently expected. Fire weather for Monday is currently not a concern with higher RH values in the low to upper 20s across the area. .LONG TERM...(Tuesday through Saturday) Issued at 259 PM MDT Sat Apr 16 2022 Overview: A progressive synoptic pattern will prevail over the CONUS throughout the long term period. A relatively low amplitude pattern is anticipated through mid-week.. followed by an abrupt increase in amplitude late in the week. Tue: Strong low-level southerly flow -- on the eastern periphery of a SFC-H85 trough in the lee of the Rockies (northern, central, and southern).. and the western periphery of a N-S oriented SFC-H85 ridge (spanning the entire MS River Valley, from Canada to the GOMEX) -- will advect relatively rich low-level moisture (H85 dewpoints 10-13C) northward from the GOMEX into the High Plains -- beneath a profound elevated mixed layer (H7-H5 lapse rates 9-10 C/km). A pronounced W-E gradient in low-level moisture /dryline/ will be present during the afternoon and early evening hours.. most likely invof the KS/CO border. While conditional instability will certainly be present on the eastern /moist/ side of the dryline, guidance suggests that extensive low stratus may also be present.. hindering diurnal heating/destabilization. Additionally, guidance continues to indicate that the main belt of westerlies will be relegated to higher latitudes (>40N), casting doubt w/regard to whether or not forcing would be sufficient for convective development. Wed-Thu: Long range guidance continues to indicate that the primary belt of mid-latitude westerlies -- and majority of shortwave energy -- will be relegated to higher latitudes (> 40N) in this period. Expect dry conditions and above normal temperatures. By the end of the week (Fri-Sat), long range guidance suggests that the synoptic pattern will undergo abrupt amplification -- in the form of a deep full-latitude/ trough -- progressing eastward from the Pacific Coast (Thu) to the Intermountain West/Rockies (Fri) and central CONUS (Sat). If this is the case -- significant /high- impact/ weather (e.g. wind, severe convection) is a distinct possibility. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 513 PM MDT Sat Apr 16 2022 VFR expected to prevail at both KGLD and KMCK through the TAF period. An area of mid level clouds over southwest Kansas is quickly moving north in the southeasterly flow, with ceilings reduced to around 5kft. Those clouds may persist through the night until a surface trough moves through Sunday morning and surface winds shift to the northwest, remaining breezy through Sunday afternoon. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Fire Weather Watch from Sunday afternoon through Sunday evening for KSZ001>003. CO...Fire Weather Watch from Sunday afternoon through Sunday evening for COZ252. NE...Fire Weather Watch from Sunday afternoon through Sunday evening for NEZ079>081. && $$ SHORT TERM...TT LONG TERM...VINCENT AVIATION...024
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1024 PM EDT Sat Apr 16 2022 .SYNOPSIS... Low pressure approaching from the Gulf states along with cool high pressure to our north will give our region another chance for rain Sunday night through Monday. Following a cool and wet Monday, dry high pressure will move in from the west with a warming trend for the rest of the week. && .NEAR TERM /THROUGH SUNDAY/... As of 1015 pm: Derived satellite imagery indicates high clouds thinning and beginning to push east of the forecast area late this evening. A weak cold front currently extends from the southern Appalachians northeast into the Virginia Blue Ridge. This boundary will sag rather slowly across the CWA through tonight/ Sunday morning, turning winds toward the NW and allowing drier near-surface air to filter in. With ample moisture lingering south of the boundary and the thinning high clouds, the potential will exist for patchy dense fog formation overnight into daybreak, mainly across southern Piedmont areas, with some potential for this to develop farther north toward the I-85 corridor, depending upon how quickly the front passes and how soon the high level moisture depletes. The slow start to the diurnal cooling cycle and elevated dewpoints will keep low temps tonight around 5 to 10 degrees above climo. Sunday morning and early afternoon will be drier as sfc high pressure nudges into the area from the north. This will lead to RH values dropping into the upper 20s to mid 30s across the NW NC Piedmont and portions of the western SC Upstate. Winds should be fairly light, so any fire weather concerns should be low. With NE winds in place much of the day, high temps will be a few degrees cooler across the NC mtns and NW NC Piedmont compared to today despite decreasing cloud cover. High temps will be slightly warmer Sunday across NE GA and the SC Upstate as cloud cover will be less over this area compared to the cloud cover we saw earlier today. A warm front will lift north out of the Deep South heading towards the CWA the second half of Sunday. This will lead to cloud cover and PoPs increasing towards the end of the forecast period. It is important to note that CAMs are not in good agreement regarding the timing of showers and isolated thunderstorms on Sunday. Currently the HRRR is the fastest solution, bringing in PoPs late morning to early afternoon. The majority of other CAMs show PoPs not increasing until late Sunday afternoon or early Sunday evening. So, confidence on PoPs will be lower than usual during the near term forecast period. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As of 245pm EDT Saturday: Rainfall chances will be steadily increasing at the beginning of the period Sunday evening and overnight as a shortwave moves across the Mid-South. Concurrently, 1028mb surface high pressure associated with a shortwave ridge over Ontario and the eastern Great Lakes will interact with a developing precipitation shield over the forecast area to induce a cold-air damming regime across the Piedmont and Foothills by early Monday morning. This will set up a chilly Monday with temperatures expected to peak about 10-15 degrees below normal area wide. Stout and moist SE flow in the lower-levels will facilitate lift atop the surface wedge as the shortwave moves across the region during the first half of the day on Monday, which should support widespread stratiform rain and some embedded heavier showers into early Monday afternoon. A soaking rainfall is expected across the area, but a deep warm-nose and shallow lapse-rates aloft should mitigate any chances of elevated convection and thunder north of the wedge front. Modest instability outside of the wedge across the lower Piedmont supports a chance of thunderstorms during the day. Expect storm-total accumulations of 0.50-1.25" through Monday evening with no excessive rainfall concerns. The progressive upper-level pattern means the surface high supporting the CAD regime will be transitory. By Monday evening the shortwave will have passed the region to the east as the next upper-level low dropping into the western Great Lakes ushers in the next cold front. Therefore, by early Monday night, the wedge will be scoured out by WNWly winds as the cold front quickly passes to the east and high pressure develops over the MS River Valley. With clearing skies and a cold airmass in place, temperatures will dip into the upper 30s over the Foothills and the lower to mid-30s in the mountains. Winds will remain elevated due to a tighter pressure gradient between the high and the coastal low, but patchy frost is possible, primarily in sheltered valley locations. On Tuesday, the high pressure will propagate east over the area and dominate our weather pattern, resulting in sunny skies. Temperature improvements compared to Monday may be negligible over the mountains due to little change in the overall airmass, but the Piedmont will see a rebound of about 8-10 degrees absent CAD. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 245pm EDT Saturday: The extended period looks fairly quiet across the area as zonal flow aloft yields to increasing heights and thicknesses Friday into the weekend, setting up a notable warming trend. We will have to contend with one more cold morning on Wednesday, as high pressure settles into the central Appalachians. Winds will be lighter than Tuesday morning and the clear skies will also facilitate low temperatures colder than Tuesday. Expect lows about 8-10 degrees below normal area wide, with some subfreezing temperatures for the higher elevations, especially across the northern mountains, and middle 30s across the northern NC Piedmont. Another round of frost will be possible. Temperatures will quickly rebound Wednesday morning, peaking later in the afternoon about 3-5 degrees below normal. A northern stream system moves across eastern Canada during the day on Thursday and a weak cold front tries to approach the area, but it has very little moisture to work with and guidance is washing out the boundary before it impacts our area. The GFS tries to activate light warm frontal precip extending from our area NW into the Midwest for Friday afternoon into early Saturday, but this doesn`t yet have support from other models. Otherwise, expect no rainfall through the period, with high temperatures on Thursday about 2-4 degrees above normal increasing to about 8-10 degrees above normal for Friday and Saturday, equivalent to the lower 80s across the warmer mountain valleys and the Piedmont. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... At KCLT and elsewhere: Low clouds that impacted the area for much of the day have largely dissipated across the Terminal Forecast Area this evening, leaving behind widespread high cloud cover. This cloud cover will steadily diminish from west-to-east over the next few hours. A cold front is expected to move rather slowly across the forecast area later tonight into early Sunday, bringing drier air. In the interim, rather moist conditions will persist, and this will lead to some concern for fog and perhaps low stratus in the time period between the clearing of the high clouds and the arrival of the drier air. At this point, it appears the best chances for restrictions will generally be confined to the terminals south of I-85 (i.e., KAND), where LIFR conditions have been added to the forecast. Cannot at all rule out some restrictions developing farther north at KGSP/KGMU/KCLT, and in fact feel the probability is high enough to warrant tempos for MVFR visby just prior to sunrise. Generally light SW winds are expected this evening, with directions expected to turn toward the NE behind the front late tonight/early tomorrow, with speeds increasing to 5-10 kts. Winds are then expected to turn toward the E/SE toward the end of the period. VFR conditions are otherwise expected at all terminals by late morning, with rain chances increasing late in the period as moisture deepens in advance of developing low pressure. However, rain chances will be such that Prob30 for -SHRA is only warranted at KAND for the past couple of hours of the period. Outlook: Rain and associated flight restrictions will overspread the Terminal Forecast Area Sunday night into Monday morning. Drying conditions and a return to VFR is expected by early Tuesday, most likely persisting through Thursday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...AP/JDL SHORT TERM...JMP LONG TERM...JMP AVIATION...JDL
Area Forecast Discussion
National Weather Service Jacksonville FL
844 PM EDT Sat Apr 16 2022 .UPDATE... The sea breeze front is approaching Trail ridge and weakening this evening with a brief pop up thunderstorm along it near Cumberland Island. A few other showers and thunderstorms across southern Georgia with one stronger one approaching Atkinson County. These showers/thunderstorms should drop off somewhere around 2 a.m. or so. Some light ground fog in the 2-4 mile range is likely toward sunrise. Should be brief in any particular location. && .PREV DISCUSSION [704 PM EDT]... .NEAR TERM [Through Sunday]... Latest short-term, high resolution guidance continues to indicate that shortwave energy currently firing widespread convection across eastern Mississippi and western Alabama will weaken as it slides across the Deep South this evening. Convective coverage should increase slightly this evening through the overnight hours for locations along and north of the Interstate 10 corridor, but intensity of these widely scattered thunderstorms should remain rather tame, as most of this activity enters our region towards or after sunset. Dry conditions will prevail overnight for locations south of I-10, with a few showers possible along the I-95 corridor towards sunrise as the weakening shortwave traverses our area and then moves offshore early tomorrow morning. Patchy to areas of fog and perhaps more widespread low stratus ceilings should develop overnight in the warm and humid air mass, especially at inland locations. Lows will only fall to the mid 60s inland and the upper 60s at coastal locations. Flow aloft will remain largely zonal on Sunday as shortwave energy moves offshore during the morning hours, followed by our area being located downstream of a fast moving shortwave trough that will be traversing the Plains States during the morning hours and the lower Mississippi Valley during the afternoon. Meanwhile, a rather persistent 100-110 knot jet streak at 250 millibars (around 35,000 feet) located over the Southern Plains and northern Texas will result in surface cyclogenesis over the Lower Mississippi Valley during the afternoon hours, with a stationary frontal boundary extending eastward from this feature along the FL/GA border lifting northward as a warm front on Sunday afternoon and evening. A warm and humid air mass will continue to prevail throughout our area, with morning fog and low stratus lifting by the mid-morning hours. The presence of the departing shortwave and the frontal boundary should combine with an increasingly unstable air mass to provide a more actively convective afternoon on Easter Sunday, with convection likely firing along both the Atlantic and Gulf coast sea breezes as they move inland. ML CAPE values will increase to around 2,000 j/kg, and mid-level temperatures will remain relatively cool (around -11 to -12 degrees Celsius at 500 millibars, or around 20,000 feet). A few storms will thus likely pulse and become strong or even briefly severe as mesoscale boundaries collide, with the primary hazards being downburst winds of 40-60 mph and small hail. Likely POPs were placed in the forecast grids for locations east of the I-75 corridor. Highs on Sunday will reach the mid 80s at most inland locations before cloud cover and convective coverage increases during the afternoon hours, while the Atlantic sea breeze keeps coastal highs around 80. .SHORT TERM [Sunday Night through Tuesday Night]... Troughing aloft will sharpen as it traverses the eastern third of the nation on Sunday Night and Monday, and low pressure will begin to deepen along a cold front over the Deep South on Sunday night. Latest short-term, high resolution guidance indicates that a squall line of strong to severe thunderstorms may traverse inland southeast GA during the late afternoon and evening hours well ahead of the sharpening trough and cold front, with damaging wing gusts and hail being the primary threats, as low and mid level flow remains rather weak and doesn`t appear to be supportive of tornadoes. The Storm Prediction Center has placed locations along and north of I-10 within a Marginal Risk of severe thunderstorm development at this time. This squall line should weaken as it crosses I-95 overnight, with some convection possible along the I-95 corridor in northeast FL overnight as well. Lows on Sunday night will remain the mid to upper 60s area-wide. Low pressure will continue to deepen by late Monday as it accelerates north-northeastward from the Carolinas towards the Chesapeake Bay, driving a cold front through our area by early Monday evening. A dry slot in the mid-levels is expected to overspread our region on Monday morning following convection during the overnight hours, which may limit convective coverage ahead of the front on Monday afternoon. Breezy southwesterly winds will again result in a warm and humid day area-wide, with highs generally reaching the 80-85 degree range all the way to the Atlantic coast. Any convection that manages to develop ahead of the approaching front will move offshore by sunset, with breezy north- northwesterly winds then overspreading our region during the evening hours, shifting to northerly towards sunrise. These winds will advect a cooler and drier air mass into our area, with lows falling to the 50s, except around 60 in north central and coastal northeast FL. High pressure will then strengthen in the wake of this frontal passage on Tuesday and Tuesday night as it traverses the Ohio Valley. Low level winds will veer to northeasterly on Tuesday afternoon, with breezy conditions continuing at coastal locations through Tuesday night. Highs will remain in the 70s on Tuesday despite full sunshine, except around 80 in north central FL. Winds will decouple at inland locations on Tuesday night, with radiational cooling resulting in lows falling to the mid to upper 40s inland, except the lower 50s across north central FL. Onshore winds will keep coastal lows in the mid to upper 50s. .LONG TERM [Wednesday through next Saturday]... Troughing aloft over the eastern U.S. will progress offshore early on Wednesday, followed by stout ridging taking shape over the southeastern states by week`s end. Surface ridging will continue to strengthen as it shifts offshore of the Mid-Atlantic coast by Wednesday evening. This weather pattern will provide an extended period of breezy onshore winds for our local area, with inland highs around 80 on Wednesday afternoon warming to the mid and upper 80s by Friday and Saturday. Onshore winds will keep highs in the 70s at coastal locations through Friday, with temperatures then approaching 80 by early next weekend. Lows in the 50s inland on Wednesday night will warm to around 60 by Friday night. A persistent onshore breeze will keep coastal lows generally in the mid to upper 60s from Wednesday night onward. .AVIATION... [Through 00Z Monday] The sea breeze front is well on it`s way west of the coastal fields with a steady flow from 120-150 degrees. HRRR is insistent a few showers might kick off as the sea breeze interacts with the old frontal boundary near Jacksonville. If this does happen it will be more likely between 02-06 UTC. Light fog inland toward sunrise with TEMPO Visibilities of 2-4SM in BR HZ. Some showers and isolated thunderstorms possible along the sea breeze front 16-00 UTC. Beyond the TAF period but a bow echo/squall line should move toward coastal GA and Jacksonville between 18/02-1808 UTC. .MARINE... A cold front moving into the Deep South overnight will stall near the Georgia waters on Sunday morning and will then lift northward as a warm front on Sunday afternoon as low pressure takes shape over the lower Mississippi Valley. Showers and thunderstorms will increase in coverage across our local waters by Sunday afternoon and evening as another cold front enters the southeastern states. Low pressure along this front will strengthen over the Carolinas on Monday, resulting in strengthening southwesterly winds. Seas of 3-5 feet will prevail both near shore and offshore through Monday afternoon. This storm system`s cold front will then cross our area on Monday evening, with strong north-northwesterly winds overspreading our local waters on Monday night, bringing Small Craft Advisory conditions to both the near shore and offshore waters after midnight. Seas on Monday night will build to 4-6 feet, with 5-7 foot seas then expected offshore from Tuesday through Thursday. High pressure building over the Ohio and Tennessee Valleys in the wake of this front on Tuesday will strengthen as it slides eastward across the Carolinas by midweek, resulting in winds quickly shifting to onshore on Tuesday, with Small Craft Advisory conditions continuing offshore through Thursday as speeds remain sustained around 20 knots. Small Craft will otherwise need to Exercise Caution over the near shore waters from Tuesday through at least Wednesday night due to sustained speeds of 15-20 knots and seas of 4-6 feet. Rip Currents: A long period northeasterly swell will become southeasterly on Sunday as it gradually fades, keeping a moderate risk in place at all area beaches. Breezy offshore winds on Monday may briefly decrease the risk to low at area beaches, with breezy onshore winds developing on Tuesday possibly creating a high risk at the northeast FL beaches. .FIRE WEATHER... Light southwest to westerly transport winds will continue on Sunday, resulting in marginally low daytime dispersion values at most locations. Showers and thunderstorms will be more widespread on Sunday afternoon and through the evening and overnight hours, with strong to isolated severe thunderstorms possible. West- southwesterly surface and transport winds will become breezy by sunrise on Monday, resulting in good to marginally high daytime dispersion values on Monday afternoon. Surface and transport winds will then shift to northerly by early Tuesday, ushering in a cooler and drier air mass into our area. .HYDROLOGY... River levels along upper portions of the Altamaha River near the Baxley gauge will crest at the moderate flooding threshold on Sunday and will then recede to minor flooding by late Monday. Minor flooding will begin downstream near the Doctortown gauge tonight, followed by minor flooding beginning along the lower Altamaha near the Everett City gauge by late Tuesday. Levels will crest near a moderate flood near this gauge towards Thursday. Minor flooding will otherwise continue through at least midweek along upper portions of the Altamaha River, and minor flooding will continue during the next several days along lower portions of the Santa Fe River near the Three Rivers Estates gauge. && .PRELIMINARY POINT TEMPS/POPS... AMG 63 83 64 80 51 / 30 70 70 60 10 SSI 67 80 66 82 56 / 20 50 60 70 20 JAX 65 83 65 83 56 / 20 60 60 60 10 SGJ 68 82 66 84 60 / 20 50 60 30 20 GNV 65 85 64 82 58 / 20 50 50 30 10 OCF 65 86 65 82 60 / 10 40 30 30 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. &&
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
521 PM MDT Sat Apr 16 2022 .DISCUSSION...(This Evening Through Saturday) Issued at 223 PM MDT Sat Apr 16 2022 Weak upper ridging is over the Rockies, while a Pac NW trough is pushing onshore. At the surface, high pressure sits over the Dakotas, with southeasterly winds across the CWA. Skies are becoming increasingly cloudy, as cirrus overspreads the region. Temps this afternoon are in the 30s and lower 40s. Tonight, the Pac NW trough will shift over the Rockies, and its surface low will move across northeastern WY into western SD. Low- level winds will increase this evening over northeastern WY, ahead of the low. RAP and HRRR forecast soundings show some of these stronger gusts (50+ mph) reaching the surface, which is supported by a few ECMWF and GFS ensemble members. Strong gusts will be more likely near any showers, but the period of gustiness is expected to be short-lived, ending as the low shifts east. Any part of the CWA could see a light rain/snow shower overnight with this system, but forecast soundings indicate a fairly dry airmass and limited moisture. Better moisture will be found to our north and east. The Black Hills could see some minor snow accumulations; additionally, central SD may receive light accumulations if the snow band sets up that far west. Sunday morning, the cold front will begin crossing the CWA, followed by strong NW winds. Strongest winds (gusts up to 60 mph) are expected to be early, across far northeastern WY and northwestern SD, when the pressure rises are greatest and low-level winds are highest. As the low shifts east, pressure rises and low-level winds decrease, so by the time of peak mixing, winds aloft will be 25 to 45 kts. Decided to go with a High Wind Warning for far NW SD and far NE WY, with wind advisories from NW SD down through south central SD. An upper ridge will build over the region early next week, bringing much warmer weather to the area. Temperatures will warm into the 40s and 50s Monday, with 60s and 70s expected for Tuesday. Southerly winds will be breezy Tuesday, ahead of Tuesday night`s cold front. A few showers can`t be ruled out with the front. Cooler and breezy conditions can be expected Wednesday, before temperatures warm again for the end of the week. Mainly dry weather will persist through Thursday. Chances for precip begin to increase Friday, when models continue to hint at another upper low crossing the northern plains. That far out, there are still a lot of track and timing differences; the 12Z GFS is much quicker and stronger with the system than the 12Z Canadian/Euro. While plentiful moisture could fall over some portion of the region, the CMC and GFS ensembles agree (for now) that the greatest chance for 0.1+ inch of 24-hr moisture next weekend is centered over MN. && .AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening) Issued At 520 PM MDT Sat Apr 16 2022 A weak disturbance will push a band of rain and light snow across the area tonight into early Sunday. The areas with the best chance of light accumulating snow will be over the Black Hills and parts of northwestern South Dakota. Mainly VFR conditions are expected through the TAF forecast period, however MVFR/LCL IFR conditions are expected over the Black Hills from 05Z tonight until 12Z Sunday morning. MVFR/LCL IFR conditions are also expected over parts of northwestern South Dakota, mainly east of a line from KHEI-KD07-KPHP from 10Z-14Z on Sunday morning. Breezy to windy southeasterly winds will occur over western South Dakota today and tonight. Gusty southerly winds, with gusts around 45kts, will develop over parts of northeastern Wyoming after 03Z this evening. A cold front will then be followed by gusty northwest winds on Sunday, especially over northwestern South Dakota, where gusts around 45kts are expected. && .FIRE WEATHER... Issued At 223 PM MDT Sat Apr 16 2022 A period of elevated fire weather conditions is expected again this coming week. On Sunday, although min RH across portions of the western SD plains will be above 25%, strong northwesterly winds will put that area in Very High fire danger. Warmer and drier weather is expected Monday, but winds will be lighter. Tuesday will be the warmest and driest day of the week, with highs in the 60s and 70s, and min RH dipping into the teens. With gusty southerly winds on Tuesday, headlines may be needed, especially since a wind shift is expected behind a cold front. Mild, dry, and breezy conditions will make Wednesday another one to watch. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory from 11 AM MDT /noon CDT/ to 7 PM MDT /8 PM CDT/ Sunday for SDZ014-032-043-044-046-047-049. High Wind Warning from 7 AM to 7 PM MDT Sunday for SDZ001-012. Wind Advisory from 7 AM to 7 PM MDT Sunday for SDZ002-013-025- 026-031-072-073. WY...High Wind Warning from 7 AM to 7 PM MDT Sunday for WYZ071. && $$ DISCUSSION...Pojorlie AVIATION...Dye FIRE WEATHER...Pojorlie