Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/23/20

National Weather Service Wakefield VA
948 PM EDT Fri May 22 2020 .SYNOPSIS... An area of low pressure will move slowly across the Ohio Valley and into the Mid-Atlantic states through tonight. Unsettled weather continues into the beginning of the holiday weekend before high pressure and drier conditions arrive for the end of the weekend into early next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 950 PM EDT Friday... Isolated light showers or sprinkles are moving through the area as another weak sfc trough rotates through the area around the Ohio Valley upper low. Best activity remains south and north of the area and the latest HRRR guidance suggests not much more than light showers this evening, with a small chance for showers near the coast overnight. Not much instability at all, and have removed mention of thunder. In fact, latest satellite imagery shows some clearing moving into western VA behind this trough. As such, have removed PoPs from the western areas after midnight and also introduced a mention of patchy fog across the Piedmont overnight with the clearing skies. Also mention patchy fog across the MD eastern shore. Otherwise, temps will drop into the lower 60s across the west and mid-upper 60s east. As of 330 PM EDT Friday... Latest analysis reveals sfc warm front lifting north across the northern neck and eastern shore attm. Radar analysis showing most activity ahead of the front now lifting north of the Mason-Dixon into PA/NJ...but a few isolated showers noted over NE NC/E VA/Delmarva. Meanwhile, to the south, a compact MCS/MCV continues to slide across the western Carolinas. This activity is associated with one last shortwave associated with the weakening upper low. HRRR and 3km NAM showing this activity reaching our area after sunset, with areal coverage of showers and storms diminishing owing to nocturnal stabilization. As such, still expecting strongest storms to remain to our SSW into central/east central NC. Timing looks to be mainly after 00-03z with pcpn moving from W-E through the night (12z CAMs shifted the timing a bit later...mainly around or after midnight). Will continue to have chc PoPs for most of the area tonight (mainly south of US-460) to account for this sct activity. While this convection will move into an area of 40-50 kt mid-level westerlies, the previously referenced loss of diurnal heating will dampen the severe wx threat over the local area significantly (SPC has MRGL and SLIGHT Risk areas just to our S/SW into the Carolinas). Still would not at all be surprised to have some rumbles of thunder and a few stronger gusts within showers over the southern third of the area, and will keep this mention in place in the HWO. To the north of this, will maintain a slight chc shower threat late tonight. Lows tonight fall into the upper 50s- low 60s NW, with mainly mid 60s across the SE half of the area. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... As of 320 PM EDT Friday... Both the weakening upper level low and its attendant sfc low moves off the Mid Atlantic coast on Saturday. While rain chances will continue to taper down, lingering low-level moisture will result in a few showers hanging around through early to mid aftn (mainly E of I-95). High temps on Saturday range from the upper 70s over the ern shore to lower 80s inland. Finally begin to see the start of a drying trend for the remainder of the holiday weekend the upper level low pushes off the northeast coast during the day Sunday, and weak sfc high pressure ridges down into the area from the NE (while sfc low pressure slowly deepens offshore). The flow shifts to the N/NE by Sun AM into Monday, bringing a short- lived pause to the moderating temp trend. Highs Sunday/Monday will only be in the mid- upper 60s over the ern shore (cooler at the beaches), with mid and upper 70s over inland VA and NE NC, with early morning lows mainly in the 50s. Only a small chance for an isolated shower or storm well inland on Sunday has been maintained (mainly over the piedmont), in association with a weakening disturbance riding along the periphery of the building upper ridge. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 320 PM EDT Friday... Good agreement among deterministic models during the medium range period, with a ECMWF-weighted model blend used for the forecast period. Aforementioned upper level ridging will bring drying conditions next week, with a gradual moderating temperature trend through much of next week. Still will have slight chance to chance pops Tuesday through Thursday mainly across western and far northern portions of the area as moisture ahead of a cutoff low over the deep south tries to occasionally sneak weak perturbations/moisture into our area. However, these will be more typical aftn/evening convection with no one day being a washout. Low-level flow veers around to the E-SE Tuesday through Thursday resulting in moderating temps, with highs in the low to mid 80s. Early morning lows during the period range from the mid 50s to lower 60s. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... As of 800 PM EDT Friday... A surface front pushing east of the terminals has allowed all sites to remain at VFR for much of the afternoon into the early evening. An upper disturbance west of the area will spread mid level clouds and perhaps a few light showers across the area overnight. Guidance suggests CIGS will drop to MVFR at SBY and ECG overnight but the remainder of the terminals will remain VFR. There are some indications that SBY may even drop to IFR CIGS overnight, but not enough confidence to forecast those conditions at this time. Generally VFR on Saturday with clearing from west to east. Outlook...Conditions are expected to improve Saturday aftn through the balance of the holiday weekend, as high pressure builds south into the region. && .MARINE... As of 330 PM EDT Friday... Surface low pressure over central VA this afternoon is expected to slowly move N/NE across the Mid Atlantic before moving off the coast tomorrow morning. SE winds this afternoon 5-10 kts over the bay and 10-15 kts over the coastal waters will become S/SW overnight. Westerly winds early on Saturday will become northerly for the second half of the day. Waves in the bay are running 1-3 ft. Seas are running 4-6 ft over the northern coastal waters and 4-7 ft over the southern coastal waters. SCA will remain for coastal zones through tonight for the elevated seas. By mid to late Saturday morning the SCA`s should end for all of the coastal zones with seas subsiding to 2-4 ft. A back door front will cross the area waters late Saturday into early Sunday. A N/NE surge behind the front with strong high pressure over northern New England may result in additional SCA winds/seas for at least the northern coastal waters. High risk of rip currents for today. Even though waves will be lower on Saturday, still looking at 7-8 second periods and N/NE flow for later in the day, so there will be a moderate risk for rip currents on Saturday. Continued NE flow and elevated seas on Sunday and Monday will result in at least a moderate risk of rip currents. && .HYDROLOGY... As of 325 PM EDT Friday... Due to recent heavy rainfall upstream, minor flooding is expected beginning late tonight on portions of the James River. A flood warning has been issued for the James River at Richmond Westham and the James River at Richmond City Locks. See FLWAKQ and FLSAKQ for more site-specific information. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ654-656- 658. Small Craft Advisory until noon EDT Saturday for ANZ650-652. && $$ SYNOPSIS...MAM NEAR TERM...MAM/MRD SHORT TERM...ERI/MAM LONG TERM...CMF/MAM AVIATION...MAM/MRD MARINE...CMF HYDROLOGY...
Area Forecast Discussion
National Weather Service Denver/Boulder CO
834 PM MDT Fri May 22 2020 .UPDATE... Issued at 833 PM MDT Fri May 22 2020 Brisk southeasterly winds are expected to continue across the plains for the next few hours as a surface low pressure area remains over the central and western portions of the state. Low level moisture will be increasing overnight with dewpoint temperatures expected to climb into the upper 40s and lower 50s. Little impact is expected overnight as the airmass is quite stable. Satellite imagery shows some high level clouds over the the mountains which will move out onto the plains overnight. Mild temperatures are expected across the plains due to increasing low level moisture and high level clouds most of the night. The only change to the forecast this evening was to remove the mention of any showers early on. One or two stray showers may move over Weld and Logan Counties around midnight, if the latest HRRR is correct. Some low pops have been left in the forecast overnight. && .SHORT TERM...(This evening through Saturday) Issued at 250 PM MDT Fri May 22 2020 Satellite pictures are still showing much of the CWA cloud free at this time. The best Cumulus development is over Logan, Washington and Douglas Counties and along the Continental Divide. There are returns on the areas radars at this time. Surface dew point values are below 30 F over the western 2/3rds of the CWA. The eastern plains have dew points in the 30s F. The wind field over the plains and foothills is south-southeasterly. There is a bit of Denver Cyclone in place. Models keep 30 to 60 knots southwesterly winds at jet level for the forecast area tonight and Saturday. There is weak upward vertical velocity on the QG Omega fields tonight and Saturday. The low levels winds transition right into normal drainage pattens later this evening from the current southeasterlies. Models have south and southwesterly flow level winds for most areas on Saturday. For moisture there is some in the mid and upper levels tonight and Saturday. Nothing great. For CAPE, there is a bit over the far eastern plains. Same goes for Saturday, but values right at the border are fairly high. This all has to do with how far west the decent low level moisture gets to. Models are not to good with this. There is a little CAPE in the alpine areas Saturday afternoon. The QPF fields show a small amount of measurable rainfall over the northern border area this evening. On Saturday afternoon, there is a bit in the mountains. For pops, nothing great this evening 10-20%s over the northern half of the plains. On Saturday afternoon, 10-30%s for much of the CWA. For temperatures, Saturday`s highs are 0-1.5 C cooler than this afternoon`s highs. .LONG TERM...(Saturday night through Friday) Issued at 138 PM MDT Fri May 22 2020 Saturday night, a moderate southwesterly flow aloft will continue over the region. The best instability in the evening will be along a dry line boundary over the northeast corner of the state. There is a marginal risk of a severe thunderstorm along and east of this boundary. Elsewhere, isolated to scattered thunderstorms with higher bases with more of a wind vs shower threat in the evening. Late Saturday night into Sunday, another mid level trough approaches the state from the northwest. A cold front will move in overnight, with weak mid and upper level qg ascent developing over northern CO on Sunday. Forecast soundings on Sunday afternoon and Sunday night show a very moist airmass in place over the forecast area. PWAT values from the GFS Buffer soundings are around 0.70 inches and moist adiabatic. Spatial cross-sections show the deepest northeasterly upslope will be Sunday afternoon and evening. It still appears to be a cool, wet and unsettled period. Models also show several inches of snowfall above timberline. Although the amounts looks like they may be overdone, could not rule out at least advisory criteria snowfall above 10 thousand feet. On Monday and Monday evening, weak qg descent in the mid and upper levels behind the trough axis. The trough axis hangs around over eastern CO through 00z before shifting eastward. This will result in another cool, unsettled and showery period. More showers vs thunderstorms, but maybe enough instability with afternoon heating to go with a slight chance of storms most areas in the afternoon and evening. Best chance of showers will be in and near the higher terrain. Tuesday into Wednesday will be drier and warmer with temperatures near to slightly above normal. A ridge axis will be over the west with a drier and more subsident north/northwest flow aloft. By Thursday, the ridge appears to keep a dry, warm and subsident airmass over the western part of the state. An upper level disturbance looks like it will drop out of WY and into northeast CO Thursday evening. This feature may stall out a bit and allow for enough moisture/instability for showers and thunderstorms over the northeast plains for Friday. The best chance of showers/storms late next week may actually be in the overnight periods. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 833 PM MDT Fri May 22 2020 South to southeasterly winds should be the only impact for the next few hours. High clouds and less wind should be the rule after about 10 PM. && .FIRE WEATHER... Issued at 250 PM MDT Fri May 22 2020 I went ahead with a Red Flag Warning for South Park and the southern CWA on Saturday afternoon and early evening. Relative humidities will be plenty low, winds speeds will be close enough. && .BOU WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon to 8 PM MDT Saturday for COZ214-241- 246-247. && $$ UPDATE...Dankers SHORT TERM.....Koop LONG TERM......Coop AVIATION...Dankers FIRE WEATHER...Koop
Area Forecast Discussion
National Weather Service Columbia SC
855 PM EDT Fri May 22 2020 .SYNOPSIS... The air mass will remain moist and unstable through the weekend and scattered afternoon and evening showers and thunderstorms are expected. Temperatures will be above normal. Temperatures will be more seasonable early next week. && .NEAR TERM /TONIGHT/... Much of the forecast area has been worked over quite well from numerous convective clusters during the afternoon and evening hours. Currently, the forecast area is dry, but regional radars showing additional showers and thunderstorms moving towards the southern/western CSRA out of southern and central GA. Portions of the CSRA did not have convection earlier, so there may still be some lingering pockets of instability for the activity to tap into as it moves into the CSRA in the next hour or so. The hrrr does show scattered activity moving through the CSRA and then into the central Midlands towards Midnight before falling apart late tonight. Will increase pops once again later tonight to account for this scenario. Expect dry weather by morning. Other issue tonight may be some fog formation. There is a weak low- level jet being shown later tonight, so confidence in widespread fog is low. Have gone with some stratus late tonight, with patchy fog possible. Temperatures in the mid and upper 60s late tonight. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Saturday and Saturday night...Upper level ridge will build across the southeastern states over the weekend. The airmass will remain moist and moderately to strongly unstable with steep low to mid level lapse rates. With 850mb west flow/warm advection expect temps around 90 degrees in the afternoon. Weak surface trough across area. There may be a weak short wave trough trigger moving to the southeast in northwest flow aloft. CAM models support scattered convection/pulse severe mainly across the north Midlands and Pee Dee in the afternoon and evening. Min temps above normal near 70. Sunday and Sunday night...Surface ridge over the Northeastern States builds down the eastern seaboard and appears a back door front will be approaching from eastern North Carolina late in the day or in the evening. A sea breeze front is also possible as low level flow becomes east. The air mass remains at least moderately unstable with steep low to mid level lapse rates. Scattered convection...isolated pulse severe...mainly in the late afternoon and evening. The convection may continue overnight but diminish as more stable air/front moves into the area. Blended temperature guidance supports max temps near 90 again with min temps above normal. && .LONG TERM /MONDAY THROUGH FRIDAY/... Front moving southwest through the area early monday and weak shallow isentropic lift may result in considerable clouds and showers mainly across the CSRA and south Midlands. The ridge will build in from the northeast with drier air for Monday night and Tuesday. Temperatures a little cooler/seasonable especially Monday. Surface ridge extending from offshore Mid Atlantic states through late week with building ridge aloft over the eastern CONUS as deep low moves into the southern Plains. Persistent east to southeast deep-layer flow for most of next week. Low chance convection through the period. Temperatures warm under ridge but with east flow should result in near normal values in the mid to upper 80s. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... Showers and storms now east of all terminals, however additional showers/storms moving up from south-central Ga will move into the CSRA in the next few hours. There remains a chance that this activity could hold together enough to reach the Midlands terminals by 06z. For now, vfr conditions prevail outside of those showers/storms. Can not rule out brief mvfr/ifr conditions if the storms impact any taf site the next several hours. Later on tonight, guidance shows ceilings/visibilities lowering down into mvfr towards morning. VFR conditions return by 13z Saturday. Additional showers/storms may be possible Saturday afternoon. EXTENDED AVIATION OUTLOOK...Restrictions possible in mainly diurnal showers and thunderstorms are possible through the weekend with improvement early next week. && .HYDROLOGY... Rainfall amounts over the past 48 hours have ranged from 3 to 8 inches across much of the upper and central portions of the river basins. This will lead to considerable river flooding on many of the area rivers through the holiday weekend. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Caribou ME
1050 PM EDT Fri May 22 2020 .SYNOPSIS... Canadian high pressure will build in overnight into Saturday. The high will move east through the Memorial Day weekend. The high will then continue east of the area through the middle of next week with a return to warmer weather conditions, along with the chance of showers and thunderstorms. && .NEAR TERM /THROUGH SATURDAY/... 955 PM Update... Cold front was making its way s moving into the Southern Penobscot Valley. The observation at BGR showed westerly winds just along the front. The front is expected to drop across the coastal waters overnight. Colder air has begun to filter in as temps across northern areas are dropping off quickly. Northerly wind staying up around 10 mph keeping temps however, especially along the elevated sites. Estcourt Station already down into the lower 40s. The latest RAP keeps winds up a bit overnight keeping the blyr mixed. NW areas will be prone to seeing frost and possibly a freeze, especially in Allagash region. Stayed close to the current forecast and modified the hrly temps and dewpoints. Previous Discussion... Large Canadian high pressure will begin to build south from Quebec tonight with a much cooler airmass overspreading the region overnight. 925 MB temperatures across the crown of Maine fall to around -3C by 12Z Saturday morning. Still some uncertainty about whether or not winds will decouple overnight, as it looks as if there will still be a bit of a gradient. Have lowered mins a few degrees across the colder valleys of the north from previous forecast, where we are now expecting lows to fall to the low to mid 30s. This necessitated adding the mention of patchy frost across the colder valleys of Northeast and Southern Aroostook counties. Have mentioned areas of frost across the North Maine Woods, but since the frost/freeze program has not begun there yet, no advisories have been issued. Saturday will feature abundant sunshine as high pressure continues to build down across the region from Quebec. High temperatures on Saturday will be much cooler than today`s, with highs generally ranging from the low 60s across the North and low to mid 60s central and Downeast. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... High pressures moves overhead Saturday night and with a fairly cool airmass in place, this sets the stage for a frost threat. Went on the cool side of guidance thanks to expected decoupling, with 30s areawide. Main question is whether mid to high clouds moving in late in the night can slow the temperature drop. High pressure moves east Sunday with southerly flow setting up. Looks warmer than Saturday in the north, but cooler Downeast thanks to onshore flow. Some mid to high clouds mainly in the north, but no precipitation. Airmass continues to warm into Monday, but due to onshore flow, it will stay somewhat cool Downeast, while far Northern Maine warms to the mid to upper 70s. Most models keep rain west of the state through Monday. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The story for the extended will be warm and unsettled. A strong blocking upper high looks to set up just to our south while an upper trough and cold front very slowly approaches us from the northwest. This will lead to warm daytime temperatures with highs mainly mid 70s to mid 80s. It also looks a bit muggy with dewpoints approaching 60 Wed/Thu. Nights will be mild with some places not dropping below 60. As the upper trough to the northwest very slowly approaches, precip chances increase Wed/Thu, and could come in the form of thunderstorms. However, models are in fairly poor agreement on how long the upper trough and cold front take to get here. General consensus is for roughly Thu night for a cold frontal passage, but that could change. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: VFR through Saturday. Gusty NW winds through early evening will become light N tonight 5 to 10 kt and around 10 kts on Saturday. SHORT TERM: Saturday Night...VFR with light wind. Sunday through Monday Night...VFR with south breeze. Tuesday through Wednesday...Chance of mainly afternoon and evening storms. Mainly VFR, though could be MVFR/IFR near the coast, and near any storms. South breeze. && .MARINE... NEAR TERM: Wind/seas will generally remain below SCA levels through Saturday. SHORT TERM: Quiet on the waters until late Tuesday into Wednesday, when south winds and seas may increase to small craft levels. Could be low clouds and fog over the waters toward Wednesday. && .FIRE WEATHER... A Red Flag Warning remains in effect until 7 PM this evening for critical fire weather conditions for much of Northern and Downeast Maine. Minimum afternoon relative humidity percentages are expected to range from 15 to 20 across far Northern areas on Saturday and the low to the mid 20s across the central highlands, Upper Penobscot Valley and Downeast Maine. Winds on Saturday will be lighter and not as gusty and it will be cooler. After coordination with the Maine State Forest Service and NWS Gray, will issue a Special Weather Statement through the weekend to highlight the heightened fire weather threat with continued dry weather conditions expected. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Hewitt
Area Forecast Discussion
National Weather Service Des Moines IA
823 PM CDT Fri May 22 2020 ...Discussion Regarding Marginal Risk for SW Iowa Tonight... .UPDATE... Issued at 810 PM CDT Fri May 22 2020 Rain showers and thunderstorms continue to pivot around the surface low centered over the Missouri River Valley as of 0100 UTC. 0-1 km SRH values have remained between 100-150 m^2 s^-2 this evening ahead of this. This SRH appears to be augmented by a weak thermal boundary currently stretched from northeast Kansas into northwest Missouri. A lot of the initiation of the current convection has occurred along this boundary. RAP analysis continues to depict surface CAPE values in the southwest forecast area over 1000 J/kg heading into the evening. The HRRR over the last few hours has also been depicting thunderstorms becoming more widespread across southwest Iowa and areas along the Hwy. 34 corridor. The biggest uncertainty is whether or not convection will remain surface based as we head into the overnight hours. Earlier runs of the HRRR were showing most of the CAPE in the mid-levels, however, a look at more recent RAP soundings indicate there may be just enough for thunderstorms to remain surface based in southwest Iowa. As the low level jet kicks in, with an already moderately sheared in environment in the lower levels, a weak brief tornado cannot be ruled out. This threat is reflected in the Marginal Risk that has been expanded eastward by SPC in the 01z Day 1 Convective Outlook. The overall threat is low, but storms late this evening and during the overnight hours will need to monitored closely in this environment. There could be a threat a of severe hail and damaging winds if greater surface based instability develops, however, a brief weak tornado appears to be the most likely severe weather feature. && .DISCUSSION.../Tonight through Friday/ Issued at 240 PM CDT Fri May 22 2020 A shortwave rounding the large western trough and deepening off the Rockies has induced an area of convection stretching from the southern plains into Missouri and Nebraska. A few areas of sprinkles or light rain have percolated across southwest Iowa throughout the early afternoon along the leading edge of warm air advection into the state. Meanwhile the surface low has been situated near the Kansas/Nebraska border as view by GOES-East day cloud phase distinction. The low will gradually lift towards central Iowa by Saturday morning, bringing showers and a few rumbles of thunder to the area. With fairly weak instability and weak shear, it is unlikely that storms will be organized enough to be severe overnight. This first round of precipitation will bring totals of around a quarter to three quarters of an inch to the area. Rain will linger in the morning across northeast Iowa through the morning, however most of the day on Saturday will be fairly quiet with subsidence allowing for clearing in the afternoon. With clouds lingering across northeast Iowa and clearing across southwest Iowa, highs tomorrow afternoon could vary quite a bit in the low 70s north to low 80s south. The parent western trough and surface low shifts east overnight into Sunday bringing our next round of showers and thunderstorms. The low- level jet increases overnight into Nebraska and perhaps far southwest Iowa helping to fuel storms, however becomes diffuse into central Iowa and will likely have less of an impact here. The severe threat will be conditional based on how much heating the area receives Sunday. With morning convection and the weak nose of the low level jet in the morning, there is some possibility that this will percolate through the day and reduces the afternoon severe threat. Warm air advection and moisture transport into the area increases resultant CAPE to 3000+ J/kg across Iowa Sunday afternoon. Again, wind shear is lacking so organized storm development may be difficult to come by. Hail and damaging winds are the main threat. It appears more likely that multicell storms will grow upscale into an MCS by the evening. The slow moving longwave trough allows for moisture transport into the area through Monday and much of early next week. Monday into Tuesday morning the boundary stalls across central to southeast IA. PWATs are between 1.5 to 2 inches across the area and with repeated rain this weekend it is unclear how well the area will be able to handle the additional moderate totals. Some localized flooding or river flooding issues may be possible by Monday into Tuesday. Still several days out but worth monitoring. Models continue to indicate lingering precipitation into Tuesday. A cutoff low across the southern plains will help to cut off some of the moisture supply into the area by Wednesday, however rain chances linger throughout the end of week. Don`t expect everyday to be a total washout, however scattered rain chances will exist each day. && .AVIATION.../For the 00Z TAFS through 00Z Saturday evening/ Issued at 626 PM CDT Fri May 22 2020 Ceilings will become IFR later this evening as a group of rain showers and isolated thunderstorms moves around the incoming short-wave feature. Rain showers will result in MVFR visibility for a few hours, but ceilings will be the main limiting factor this evening. Rain showers will continue off and on through much of the TAF period. Ceilings will mainly be low-end MVFR for much of Saturday. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Krull DISCUSSION...Hagenhoff AVIATION...Krull
Area Forecast Discussion
National Weather Service Grand Rapids MI
757 PM EDT Fri May 22 2020 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 315 PM EDT Fri May 22 2020 - Mostly Cloudy Tonight - Increasingly Warm and Humid; Thunderstorms Saturday Night - Chance of Showers And Storms Early to Midweek && .DISCUSSION...(This evening through next Friday) Issued at 315 PM EDT Fri May 22 2020 - Mostly Cloudy Tonight - The upper low will continue to bring fairly extensive cloud cover tonight. A few lingering showers mainly to the east and north of KGRR will taper off late this afternoon and early evening. Patchy fog will develop during the early morning hours Saturday and could be a little more prominent over our se fcst area due to a Lake Erie connection give light east winds as suggested by HRRR guidance. - Increasingly Warm and Humid; Thunderstorms Saturday Night - Fair wx is forecast for most of the day tomorrow with weak ridging in place. A warm front combined with an upper level disturbance will bring showers and storms Saturday night into early Sunday. Overall guidance trends and the 12Z HREF LPMM show potential for more rain Saturday night (potential for a half an inch to inch of rainfall with locally higher amounts across portions of our lakeshore counties). Deep layer shear will gradually increase but severe wx is unlikely given fairly weak instability. Trends in a consensus of latest model guidance suggest extensive cloud cover will likely linger Sunday morning. Some clearing will develop later in the day and allow high temps to reach well into the 70s along with increasing humidity. Due to persistent deep southwest flow waa high temperatures will reach the lower 80s by Memorial Day with dew points rising well into the 60s by then. There is a chance for showers and storms Monday as the increasingly warm and humid airmass interacts with a sfc/upper trough to the west. However the majority of the holiday weekend will be dry. - Chance of Showers And Storms Early to Midweek - A stationary frontal boundary will likely focus development of showers and storms Tuesday through midweek. This potential will be aided by potentially moderate instability and several upper level disturbances which will move through as well as forcing from the lake breeze. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 757 PM EDT Fri May 22 2020 VFR conditions are in place across the area at 00z. There are a few locations reporting MVFR ceilings off to the east and south, but these are scattered and will likely lift to VFR this evening. The main question is will we developing fog and stratus tonight with light winds and skies trying to clear some with the loss of daytime heating. The short answer is yes, but it should not we widespread and low. We are expecting some fog and stratus to develop tonight, with the best chances being along the I-94 corridor. BTL and JXN are the TAF sites that we hit the hardest with IFR conditions expected towards daybreak. Conditions should improve to VFR once again in all areas Saturday morning. Winds will be light and variable tonight becoming southeast at 5 to 10 knots on Saturday. && .MARINE... Issued at 315 PM EDT Fri May 22 2020 Easterly winds will continue into Saturday and result in minimal wave heights. A few thunderstorms could pose a hazard to mariners Saturday night and on Memorial Day. Areas of dense fog are likely to develop Sunday through Memorial Day as a much more humid airmass overruns relatively cold lake waters. && .HYDROLOGY... Issued at 315 PM EDT Fri May 22 2020 The crest on the Grand River is now passing through downtown Grand Rapids, and will be arriving along the lakeshore (Robinson Township) by Saturday morning. Major flooding continues in Comstock Park, though the river has begun to drop. Flooding also continues along the Muskegon River, as well as many of the smaller tributaries around our area. Here are some of the noteworthy crests experienced so far on the Grand River: Ionia: 7th highest crest on record (1.20 feet less than 2018) Lowell: 8th highest crest on record (0.97 feet less than 2018) Ada: 3rd highest crest on record (0.94 feet less than 2018) Comstock Park: 7th highest crest on record (0.45 ft less than 2018) Grand Rapids: 4th highest crest on record (1.12 ft less than 2018) Robinson Twp (forecast): 6th highest crest (0.48 ft less than 2018) Rain returns to our area tomorrow night (Saturday night), and will be mostly concentrated along the lakeshore counties. While this rain is not expected to result in renewed rises on the rivers, ponding of water on roadways and low spots is possible since the soils remain completely saturated. Additional chances of rain will linger around Lower Michigan for the bulk of next week. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SYNOPSIS...Laurens DISCUSSION...Laurens AVIATION...Duke HYDROLOGY...AMD MARINE...Laurens
Area Forecast Discussion...Updated
National Weather Service Phoenix AZ
450 PM MST Fri May 22 2020 .UPDATE...Updated aviation discussion. && .SYNOPSIS... Near normal temperatures will last through the weekend while a series a dry weather systems move north of the region. Breezy to locally windy and dry conditions today will lead to elevated fire weather conditions. Increasing high pressure through the first part of next week will push temperatures to well above normal readings by the middle of next week, potentially leading to a period of excessive heat conditions by next Wednesday. && .DISCUSSION... Latest water vapor imagery reveals a well-defined trough across the Great Basin. Ahead of this system, the pressure gradient has tightened, resulting in a southwesterly flow and areas of breezy/windy conditions across the Desert Southwest. The winds combined with single-digit RHs will yield widespread elevated fire danger. Latest HRRR depicts the strongest winds developing late this afternoon across the wind-prone locations of southwestern Imperial County, where localized gusts up to 50 mph will be possible. Elsewhere, winds will generally gust to 20 to 30 mph before subsiding this evening. The aforementioned trough will migrate eastward Saturday, though a reinforcing vort max diving down the West Coast will induce a trough across Arizona. This will keep the afternoon breeziness going along with providing a few degrees of cooling, with temperatures falling below average. Sub-one-hundred degree high temperatures in the lower deserts will hang on for one more day Sunday as well. ECMWF and GFS ensembles continue to indicate a steady warming trend through at least next Friday as the forecast area eventually becomes situated between a cutoff low in the eastern Pacific and an upper low across the southern Plains. Pseudo omega block will translate into a prolonged period of well-above average temperatures. Forecast was weighted heavily towards the latest NBM, which is exhibiting low variability. Strongest EPS height anomalies appear to remain to our north and west, though temperatures will still likely exceed the 95th percentile of climatology and even approach daily records. An Excessive Heat Watch was issued early today for the lower deserts and remains in effect for next Wednesday through Friday. && .AVIATION...Updated at 2350Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Another upper level low passing by to the north will result in gusty southwest to west winds for the remainder of the afternoon and through the middle of the evening. There may be a bit of variability thru about 01z but afterwards winds should be well mixed and hold their directions better through midnight. Expect prime window for peak gusts to be in the 01-04z range, with peak gusts to around 25kt. After midnight winds should taper off and return to the east or southeast after about 09z and at KPHX winds likely to return to the east at or after 10z. Winds should swing back to the southwest/west after 19z Saturday but be a bit less strong and gusty as compared to today. Otherwise, skies to be generally clear although FEW-SCT high and thin cirrus decks are likely during the TAF period. Southeast California/Southwest Arizona including KIPL and KBLH: An area of low pressure passing by to the north will lead to rather breezy and gusty southwest to west wind for the remainder of the afternoon and well into the evening hours today. Peak gusts could approach 30kt at times with the best window for strong gusts in the 01z to 04z period. Winds will taper off gradually after 05z and into the morning hours, becoming more northwest to north especially at KBLH. During the day Saturday there will be much less wind, typically speeds of 10kt or lower. Skies will be generally clear with the potential for a few high thin cirrus decks at times during the TAF period. && .FIRE WEATHER... Monday through Friday: High pressure building into the region early next week will lead to much warmer temperatures, with highs climbing above 100 degrees starting Monday. High temperatures eventually climb above 105 degrees starting Tuesday or Wednesday. Winds into next week will be fairly light day to day with only locally breezy afternoon conditions. Although red flag thresholds are not expected to be reached, excessive heat appears likely late in the week, which could promote new fires. Through the period, expect Min RH values to dip below 10% on the lower deserts (below 15% higher terrain) with Max RH values around 20-30% for lower desert locations and 30-40% for higher terrain locations. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from Wednesday morning through Friday evening for AZZ530>551-553>556-559. CA...Excessive Heat Watch from Wednesday morning through Friday evening for CAZ561>570. Wind Advisory until 5 AM PDT Saturday for CAZ562. && $$ DISCUSSION...Hirsch AVIATION...CB FIRE WEATHER...Hirsch/Smith/Kuhlman
Area Forecast Discussion
National Weather Service Reno NV
215 PM PDT Fri May 22 2020 .SYNOPSIS... Low pressure will bring breezy winds, cooler temperatures, and showers with a few thunderstorms today mainly for west-central Nevada. Tonight will be chilly with freezing temperatures possible for some valleys. Memorial Day weekend will be dry with a major warmup through next week. A few thunderstorms may develop as early as Wednesday with increasing chances later in the week. && .DISCUSSION... Isolated showers and gusty winds will continue through this afternoon as a cold front sweeps through the Sierra and western Nevada. A band of showers is currently stretching from just north of I-80 from Chico, CA, all the way to Lovelock, NV. There are additional bands of showers south of I-80 as well near Stagecoach/Hazen and even more showers across Mineral and Churchill counties. HRRR shows these showers slowly migrating south across the Sierra and western Nevada through the afternoon, but then largely dissipating by sunset. Surface winds will drop off for most locations tonight, except for the higher elevations where breezy east to northeast winds will increase through early Saturday. Temperatures will fall into the 30s for most areas tonight, with a cooler, drier air mass in place. Lows below freezing will be possible for some rural locations and plan for 20s in the Sierra valleys. Another night of keeping watch of those cold-sensitive spring plants, but it should be the last for awhile. Dry conditions along with light winds will be in place for much of the Memorial Day weekend as high pressure returns to the West. Not to jinx it or anything, but it will be prime BBQ weather this weekend, before it really heats up next week. The coming week is looking quite warm with high pressure strengthening overhead. We will start to see temperatures climb into the low-to-mid 90s by midweek for western Nevada. Plan for above normal temperatures much of next week. There will be some potential for slightly cooler temperatures later in the week as cloud cover from thunderstorms may provide some relief. Generally for much of the Sierra and western Nevada, there will be above normal temperatures, light winds, and relatively sunny skies through at least Wednesday. Thunderstorm potential will be tricky this many days in advance, but we are seeing some parameters consistently highlighting the potential for it, especially given the weather pattern. High pressure with a weak low sweeping in warrants chances each day for storms starting on Wednesday afternoon/evening. NBM thunderstorms probs also targeting this time, with 10-20% chances each afternoon/evening starting on Wednesday. Primary areas of thunderstorm potential will be the Sierra (roughly Alpine, Mono counties) Wed-Thurs, and then the chances for thunderstorms spread into Lassen/Plumas counties as well. If you have outdoors plans (e.g. camping, hiking, boating, etc.) be sure to keep an eye on the 2x/daily updates from the National Weather Service. It will be quite summer-y next week, so a good rule of thumb is to complete your outdoor activities before the afternoon when the thunderstorm risk goes up! Or be sure to have a backup plan for taking shelter from hail, rain, and lightning. -Edan && .AVIATION... A cold front dropping through the region this afternoon will keep gusty winds across the Sierra and western Nevada along with some showers with maybe a couple of thunderstorms. The best potential for thunderstorms will be east of Highway 95, but a band of showers just north of the I-80 corridor will likely hold together through the evening with light-to-moderate showers and lower ceilings. HREF showing the band of showers slowly breaking up as it migrates slowly south through the evening, so KRNO may get very little if not any precipitation. Surface winds will decrease behind the front this evening, but east to northeast winds may be breezy in the Sierra. There will still be an enhanced potential for turbulence across and west of the Sierra with the breezy east winds. High pressure builds in with lighter winds Sunday and continue into next week. By the middle of next week we should be seeing afternoon and evening thunderstorms developing along the Sierra. -Edan && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Springfield MO
645 PM CDT Fri May 22 2020 .SHORT TERM...(This evening through Saturday) Issued at 248 PM CDT Fri May 22 2020 After a very active morning across southeast Kansas and the Missouri Ozarks, the showers and storms were exiting the eastern Ozarks. This morning convection has really worked over the atmosphere and current indications that recovery will be quite limited for additional severe storms this afternoon and evening. In addition, the storms were proficient rain makers with locally heavy rain and flooding being reported. Hi-Res CAMS still showing the potential for a few storms late this afternoon and evening, with the NAM Nest the most robust and the latest HRRR now showing development as well. However, still uncertain if enough instability can develop for anything severe. Did lower overall probabilities this evening with only isolated to scattered storms expected at best and this would be mainly through 06Z. Some weak upper level ridging builds in late tonight through Saturday and should for the most part should squelch much in the way of showers and storms. Did keep lower end probabilities going, especially Saturday afternoon with the moist and unstable airmass in place. Saturday looks to be a warm and humid day with highs in the lower to middle 80s and dewpoints in the upper 60s. Again relatively quiet weather is expected Satruday night with lows in the 60s. .LONG TERM...(Saturday Night through Friday) Issued at 248 PM CDT Fri May 22 2020 At this point it looks as though upper ridging will hang on into Sunday morning before pushing off to the east Sunday afternoon. However, still high precipitable water values along with modest instabilities will result in mainly diurnally driven convection on Sunday, The pattern for Monday and Tuesday is for a trough over the mid section of the conus with ridging along the east coast. By Tuesday afternoon medium range guidance suggests an upper low forming over Oklahoma and then slowly sagging southward into Texas by Thursday and Friday. This will keep the area in a southerly moist flow through the period with high precipitable water values along with periodic rain chances. Given antecedent soil conditions this will only aggravate the flooding potential. Overall, temperatures through the period will be seasonal with highs right around 80 and lows in the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 637 PM CDT Fri May 22 2020 Models continue to show a decrease in coverage of showers and storms this evening. As such, did not include any precipitation in this TAF issuance. Can`t rule out some isolated storms this evening at all sites, and possibly overnight at KBBG, but potential is too low at this point to put in the forecast. Additional showers and storms will be possible Saturday afternoon and evening. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Raberding LONG TERM...Raberding AVIATION...Titus
Area Forecast Discussion
National Weather Service Shreveport LA
910 PM CDT Fri May 22 2020 .UPDATE... The latest run of the HRRR is capturing the ongoing severe convection in S OK/N TX quite well and has it moving into the I-30 corridor just before midnight tonight. Currently, only McCurtain County is in a Severe Thunderstorm Watch in our area; will have to closely monitor this situation as the evening progresses. This activity will spread slowly eastward into SW AR into the early morning hours, thus will not make any major changes to the forecast at the moment. /35/ && .PRELIMINARY POINT TEMPS/POPS... SHV 71 90 71 87 / 30 30 10 50 MLU 71 91 72 89 / 10 30 10 40 DEQ 67 87 68 85 / 50 20 10 50 TXK 70 88 70 85 / 50 30 10 50 ELD 70 90 70 88 / 40 30 10 30 TYR 70 88 72 84 / 30 30 10 60 GGG 70 89 71 86 / 30 30 10 60 LFK 73 91 72 87 / 20 30 10 60 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$