Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/22/20

Area Forecast Discussion
National Weather Service Albuquerque NM
300 PM MDT Thu May 21 2020 .SYNOPSIS... Isolated thunderstorms are possible this evening over northeast New Mexico along a weak frontal boundary. The front will retreat Friday, with critical fire weather conditions developing over northeast New Mexico. Critical conditions will be more widespread over eastern New Mexico Saturday. A change in the weather pattern will occur early next week as cooler and moist air invades the east and an upper low develops over the state. Chances for showers and storms will be most widespread from the central mountain chain over the plains Sunday through Memorial Day. The upper low will wobble slowly to the east thereafter, so shower and storm chances may trend downward by mid week while temperatures warm. && .DISCUSSION... .SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)... As one low migrates north to the Canadian border, a second low will be dropping down from the Pacific NW over the next several days. Meanwhile, a relatively dry shortwave trough will trek across the state, leading to breezy to locally windy conditions along and east of the central mountain chain. With the region of higher dewpoints shifting further east, the HRRR has become less enthused with the idea of convection across Union County this afternoon. The HREF on the other hand shows precipitation increasing ahead of a surface low through 09z. A stray thunderstorm or two cannot be ruled out, given the negative LI`s and marginal CAPE (200-400 J/kg). Overnight, the northern mountains can expect temperatures near or below freezing, but decided to hold off on another Freeze Warning for this evening. On Friday, a leeside trough will increase southwesterly winds east of the central mountain chain. Daytime highs will continue to follow the warming trend, with much of the state near or above normal. LONG TERM...(SATURDAY THROUGH WEDNESDAY)... Saturday will be breezy to windy and very dry as upper trough/low moves into the Great Basin and central Rockies. Highs Saturday will range from near average west and central to about 10 degrees warmer than normal over the east. Some energy will develop southward into the trough Sunday, allowing a second upper low to be generated over northern NM. At the same time, a cold front will surge into the northeast then to the east slopes of the central mountain chain Sunday night/Monday. There are timing differences between the models in regards to the front and exactly where the upper low center will be. However, the main message is that there will be a cool down by Sunday night and Memorial Day with highs on Memorial Day about 5 to 15 degrees below average, and chances for showers and storms, especially from the central mountain chain over the plains. Chances for rain taper off Tuesday and Wednesday as temperatures slowly warm back to above normal. The upper low could hang around through next week, with NM in the backwash, so the warming and drying trend for the east in the grids may be a bit ambitious if the operational GFS turns out to be accurate. && .FIRE WEATHER... Breezy to locally windy conditions this afternoon and evening will lead to a brief period of critical fire weather conditions from Clines Corners to Conchas, as a shortwave trough crosses New Mexico. On Friday, the warming trend will continue, with temperatures up to 10 degrees above normal across the eastern plains. Minimum relative humidities will be less than 10% across much of the state. Strong south to southwesterly winds will develop in the afternoon hours Friday east of the central mountain chain, due to a leeside trough. Thus, the Fire Weather Watch across the northeast highlands was upgraded to a Red Flag Warning, as these conditions continue for several hours in the afternoon. Widespread critical fire weather conditions are also forecast for much of the eastern plains on Saturday. Winds will increase as the leeside trough deepens. Combined with high Haines values and temperatures 5-10 degrees above normal across the east, this was the basis for the Fire Weather Watch in effect for Saturday. Ventilation rates will start off poor to fair on Friday, becoming excellent by Saturday. As a low dives down toward New Mexico combined with a backdoor cold front Sunday and Monday, there is a chance for wetting precipitation across much of the eastern plains Monday and cooler temperatures forecast, which should help mitigate some of the fire weather concerns across the eastern portion of the state. && .AVIATION... 18Z TAF CYCLE VFR conditions to prevail through the TAF period. Breezy conditions will develop this afternoon (up to 25 kts), as a dry shortwave treks eastward across the state today. Low-level moisture should stay well east of the NM/TX border, but a stray thunderstorm or two is possible across the far northeastern corner of the state. The HREF keeps convection going after 09z, but the HRRR is less enthused about any precipitation. Some brief MVFR ceilings may be possible, but it shouldn`t impact any TAF sites. 31 && .PRELIMINARY POINT TEMPS/POPS... Farmington...................... 38 81 47 79 / 0 0 0 0 Dulce........................... 30 77 35 75 / 0 0 0 0 Cuba............................ 38 76 43 76 / 0 0 0 0 Gallup.......................... 28 78 36 76 / 0 0 0 0 El Morro........................ 32 75 36 73 / 0 0 0 0 Grants.......................... 30 79 37 78 / 0 0 0 0 Quemado......................... 35 77 39 76 / 0 0 0 0 Magdalena....................... 43 80 47 80 / 0 0 0 0 Datil........................... 38 76 42 75 / 0 0 0 0 Reserve......................... 35 77 38 79 / 0 0 0 0 Glenwood........................ 44 80 49 82 / 0 0 0 0 Chama........................... 29 70 33 70 / 0 0 0 0 Los Alamos...................... 48 75 50 76 / 0 0 0 0 Pecos........................... 41 75 46 76 / 0 0 0 0 Cerro/Questa.................... 33 75 39 75 / 0 0 0 0 Red River....................... 29 65 36 64 / 0 0 0 0 Angel Fire...................... 21 69 29 68 / 0 0 0 0 Taos............................ 30 78 35 76 / 0 0 0 0 Mora............................ 37 75 41 75 / 0 0 0 0 Espanola........................ 42 81 47 82 / 0 0 0 0 Santa Fe........................ 43 77 45 76 / 0 0 0 0 Santa Fe Airport................ 40 80 43 79 / 0 0 0 0 Albuquerque Foothills........... 50 81 53 82 / 0 0 0 0 Albuquerque Heights............. 49 82 52 83 / 0 0 0 0 Albuquerque Valley.............. 47 84 51 85 / 0 0 0 0 Albuquerque West Mesa........... 48 82 52 84 / 0 0 0 0 Belen........................... 44 85 48 86 / 0 0 0 0 Bernalillo...................... 45 83 50 85 / 0 0 0 0 Bosque Farms.................... 45 84 48 85 / 0 0 0 0 Corrales........................ 47 83 50 85 / 0 0 0 0 Los Lunas....................... 45 85 48 85 / 0 0 0 0 Placitas........................ 46 81 51 80 / 0 0 0 0 Rio Rancho...................... 47 82 51 84 / 0 0 0 0 Socorro......................... 48 86 51 88 / 0 0 0 0 Sandia Park/Cedar Crest......... 44 77 46 77 / 0 0 0 0 Tijeras......................... 42 79 47 79 / 0 0 0 0 Edgewood........................ 36 79 44 79 / 0 0 0 0 Moriarty/Estancia............... 33 80 42 81 / 0 0 0 0 Clines Corners.................. 40 77 44 77 / 0 0 0 0 Mountainair..................... 40 79 45 79 / 0 0 0 0 Gran Quivira.................... 42 79 47 79 / 0 0 0 0 Carrizozo....................... 50 81 53 82 / 0 0 0 0 Ruidoso......................... 46 76 50 76 / 0 0 0 0 Capulin......................... 41 77 45 79 / 20 5 0 0 Raton........................... 40 82 43 83 / 10 0 0 0 Springer........................ 41 83 44 83 / 5 0 0 0 Las Vegas....................... 40 78 44 78 / 0 0 0 0 Clayton......................... 52 82 51 87 / 20 0 0 0 Roy............................. 47 80 47 83 / 0 0 0 0 Conchas......................... 51 88 53 91 / 0 0 0 0 Santa Rosa...................... 48 87 54 89 / 0 0 0 0 Tucumcari....................... 55 91 56 94 / 0 0 0 0 Clovis.......................... 51 87 54 91 / 0 0 0 5 Portales........................ 52 89 55 93 / 0 0 0 0 Fort Sumner..................... 51 88 53 92 / 0 0 0 0 Roswell......................... 53 93 55 96 / 0 0 0 0 Picacho......................... 52 87 54 89 / 0 0 0 0 Elk............................. 49 83 52 84 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Saturday morning through Saturday evening for the following zones... NMZ103-104-108. Red Flag Warning from 1 PM to 7 PM MDT Friday for the following zones... NMZ103. && $$
Area Forecast Discussion
National Weather Service Denver/Boulder CO
901 PM MDT Thu May 21 2020 .UPDATE... Issued at 901 PM MDT Thu May 21 2020 Have updated the forecast to remove evening showers over the Palmer Divide and added an area of showers through midnight over the far northeast plains. Late afternoon cloudiness over the mountains and foothills has been dissipating except near the Wyoming border where a few showers with more vertical development had formed. This trend will continue, however the HRRR shows the convection over the southeast corner of Wyoming sticking together for a few hours and moving over Logan and northern Washington Counties. Have thrown in isolated thunderstorms up til midnight over these areas. Otherwise the forecast is unchanged. Will need to keep an eye out for any areas of stratus developing over the eastern plains, as thunderstorms over western Kansas are expected to produce a lot of rain and rain-cooled air which could move back across eastern Colorado overnight. At the present time, there is quite a cirrus shield over northeast Colorado, produced by the southwestern Kansas convective complex. That will make it difficult to monitor the progress of any stratus clouds, at least over the next few hours. && .SHORT TERM...(This evening through Friday) Issued at 239 PM MDT Thu May 21 2020 Temperatures have been around seasonal normals today after being at or near record highs the past two days. Conditions have been pretty stable but a few clouds are beginning to develop over the southern Front Range foothills. These clouds will continue to grow through the late afternoon and evening and will produce high based showers that spread over the urban corridor. Not much rain, if any, is expected to reach the surface but these showers could produce wind gusts up to 35 mph. Tonight, a few showers and storms may develop on the south side of the Palmer Divide and may work their way over to Lincoln County around midnight. Otherwise, lows will be around seasonal normals with light winds and dry conditions. A few low clouds may spread across the far eastern plains as moisture works its way back into the state. Mid to upper level ridging will be over our forecast area on Friday. The subsident flow will keep skies clear for much of the day allowing for temperatures to warm 5 to 10 degrees above normal. High based showers will again be possible over the foothills and urban corridor with more wind than rain. Otherwise, relative humidities will drop to the low teens across the majority of our CWA except for the higher terrain in the mountains. With winds expected to be on the lighter side, a Red Flag Warning won`t be needed. .LONG TERM...(Friday night through Thursday) Issued at 239 PM MDT Thu May 21 2020 Models have weak to moderate southwesterly flow aloft for the CWA Friday night through Sunday. Models have an upper trough move into Colorado on Sunday, then move slowly eastward across the state through Monday night. The QG Omega fields have upward vertical velocity progged for the CWA Friday night through Sunday night. The low level winds look to be normal drainage patterns Friday night. It looks like southerly winds prevail on Saturday, then a surge of upslope moves in Saturday evening. North northeasterly winds prevail most of Saturday night. Northerly upslope winds are progged much of Sunday, Sunday night on into Monday. For moisture, there is some around Friday night through Saturday night, but there is an increase in moisture for Sunday and Sunday night. There is limited CAPE progged over the plains Friday evening. CAPE values are pretty decent Saturday late day, mainly over the eastern half of the plains. On Sunday, there is CAPE over the mountains and foothills; not much on the plains with the more stable, cooler airmass in place. Cross sections show a pretty strong cap just above 700 mb. Will leave some 10% pops over the far northeast corner Friday evening. Late day Saturday`s pops will be 20-40%s in the mountains and foothills, with 10-20%s over the plains. Sunday is the best shot at some needed rain. Will go with 30-60% pops across all the CWA Sunday well into Sunday night. For temperatures, Saturday`s highs are 0-2 C cooler than Friday`s. Sunday`s readings cool of some 6-12 C from Saturday`s. For the later days, Monday through Thursday, models show a weak upper trough/closed low over the CWA and southern Colorado. Monday should stay cool with some moisture around. From Tuesday through Thursday, models keep an upper closed low over the panhandle of Texas, with weak flow aloft over the CWA. It looks pretty dry with an increase in moisture on Thursday. Temperatures are below season normals on Monday, near normals on Tuesday, then a tad above normals Wednesday and Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 901 PM MDT Thu May 21 2020 No major aviation impacts over the next 12 to 24 hours, unless a deck of low stratus forms over the eastern plains and moves back into the Denver area. If the stratus forms, then MVFR/IFR cloud decks could affect the morning arrival rates. Winds will be east to southeasterly overnight. && .FIRE WEATHER... Issued at 239 PM MDT Thu May 21 2020 The minimum relative humidity progs are in the 10-15% range over much of the southern third of the CWA Saturday afternoon and early evening. Most areas don`t show high enough wind speeds to warrant a Red Flag Warning, however, South Park and Lincoln County show speeds getting close to criteria. It will need to monitored for potential highlights. Sunday cools off considerably with decent enough moisture around for wetting rains in nearly all of the forecast area. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Dankers SHORT TERM.....Danielson LONG TERM......RJK AVIATION...Dankers FIRE WEATHER...RJK
Area Forecast Discussion
National Weather Service Dodge City KS
555 PM CDT Thu May 21 2020 ...updated aviation... .SHORT TERM...(This evening through Friday) Issued at 226 PM CDT Thu May 21 2020 MSAS showing weak surface low pressure centered over the western Oklahoma panhandle with attendant cold front from wet of Syracuse into southwest Nebraska this afternoon. Also a dryline and warmfront extended south from near LBL into the Texas Panhandle. Ahead and east of these features has been a stubborn field of stratus clouds that has created a large temperatures difference from the upper 60s to low 70s under the cloud cover and contrasted by low 80s over the Sunny Syracuse-Johnson-Elkhart area. Latest HRRR initiate these convective elements at 21 UTC along the cold front along the highway 25 corridor with organized elements reaching the highway 83 corridor by around 10 pm. In addition to a hail and 60-70 mph wind threat, a sizable area of 1 to 2 inch rain is likely with more localized areas of 3 and 4 inches just as likely. Increased Pops over the area as widespread trailing stratiform precipitation is likely beyond midnight even as the overall severe risk should be decreasing. Uncertainty with respect to and additional marginally elevated severe pulse hail storms in the southeast will revolve around mid level wave that will be moving into the area during the overnight hours. Lows are forecast from the mid 50s west to more mild summerlike 60s across south central Kansas. .LONG TERM...(Friday night through Thursday) Issued at 226 PM CDT Thu May 21 2020 Potential exists for thunderstorms to be ongoing early Friday morning across the eastern and especially south central Kansas counties as models show a mid level trough/weak pvu anomaly moving though the area with still conditionally unstable air. This should clear out though with sky becoming sunny area wide by afternoon resulting in temperatures warming into the 80s all the way to Hays. It will likely remain inactive later in the day Friday with respect to convection, however the 850 wind field transitions from weak easterly flow Friday to veering and increasing winds though Saturday, with stronger south winds, and better moisture transport ahead of a dryline for Saturday late afternoon and Saturday evening. As a result , convection is possible Saturday across the eastern counties. The southwest winds will make temperatures much warmer on Saturday, before a cold front tempers highs and focuses severe weather chances once again along a southward propagating cold front through Sunday night. This will setup Monday to likely be cooler and cloudy and perhaps showery with diurnal thunderstorms. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 555 PM CDT Thu May 21 2020 The main concern for the TAF forecast is +TSRA for the terminals this evening. All modes of severe threats will be possible with this activity... landspouts, large hail, and severe outflow winds of 50+kt. Mid to late evening is the most likely time of impacts to the terminals. This activity will eventually evolve into a line and move out of the terminal space by 06Z. Tranquil weather is expected thereafter. With continued moisture advection, MVFR cigs may be possible once again by 12Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 56 81 59 91 / 60 20 0 0 GCK 53 81 56 91 / 80 10 0 0 EHA 54 84 56 91 / 40 10 0 0 LBL 54 83 58 93 / 50 20 0 0 HYS 57 80 56 88 / 80 20 10 10 P28 61 81 61 90 / 70 60 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Sugden
Area Forecast Discussion...CORRECTED
National Weather Service Quad Cities IA IL
1013 PM CDT Thu May 21 2020 ...00Z AVIATION UPDATE... .SYNOPSIS... Issued at 302 PM CDT Thu May 21 2020 RAP analysis placed an upper low over NW Kentucky, slightly north of where it was yesterday. This subtle retrogression has ensured that we stay under the widespread low clouds today into tonight. Temps so far this afternoon were well below normal ranging from the upper 50s to lower 60s. We should warm several more degrees by the late afternoon. && .SHORT TERM...(This Evening through Friday) ISSUED AT 302 PM CDT Thu May 21 2020 Light ESE winds are expected overnight as temps cool into the 50s. There is a slight chance for patchy drizzle, but most locations will probably stay dry. On Friday, the nearly stationary upper low that brought 6+ days of low clouds to the Upper Mississippi Valley will begin to track into the Eastern U.S. Subsidence behind the low should lead to occasional breaks in the cloud cover, allowing highs to reach the lower 70s. Uttech .LONG TERM...(Friday Night through Thursday) ISSUED AT 302 PM CDT Thu May 21 2020 Models are coming into better agreement with a stalled but active pattern across the Plains for the next week. The main forecast concerns were chances of precipitation through the period. This weeks pesky upper level low will be shifting to the east Friday night into Saturday as a 500 MB shortwave trough lifts from southern Plains and into the Great Lakes by Saturday night. This will mark the transition to a 500 MB pattern featuring a trough in the west and a ridge in the east through early next week. This will result in a southwesterly flow aloft from the Southwest into the Great Lakes region. The pattern begins to break down on Tuesday as a vort max dropping into the base of the western trough and closes off resulting in another block forming in the atmosphere across the southern US. This will result in a stalled but active pattern through the end of next week. The main belt of the westerlies will be just to our north through the period. This will result in periods of showers and thunderstorms through the week as pieces of energy pass to our north or eject towards the area from the closed low. This could potentially leave a warm and humid airmass across the Plains for much of the week. Precipitable water values through the week are in the 1.50 to 1.75 inch range which is about 125 to 150% of normal so there could be the potential for locally heavy rainfall. Temperatures are forecast to be in the upper 70s to lower 80s which is near to slightly above the normal temperatures which are in the mid to upper 70s this time of year. In the Friday night timeframe, a low level jet of 20 to 30 knots will develop ahead of the lifting shortwave bringing showers and thunderstorms to the area Friday night into Saturday. The better lift will shift off to the east after 12 UTC on Saturday with showers and thunderstorm chances coming to an end. Shortwave ridging will build into the area Saturday afternoon into Sunday bringing a dry period to the area. Temperatures will be noticeably warmer with highs around 80 and dewpoints in the mid 60s. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) ISSUED AT 611 PM CDT Thu May 21 2020 Persistent stratus will remain over the area overnight through much of Friday with ceilings primarily in the MVFR range. The exceptions will be early this evening, with some sites initially VFR before ceilings begin to lower, and the other will be mid to late afternoon Friday, when lifting ceilings may bring VFR conditions. There is a potential for patchy drizzle late tonight, but confidence is not high enough to include this in the forecasts. && .HYDROLOGY... Issued at 1034 AM CDT Thu May 21 2020 The Rock River has crested at Joslin and Moline and are currently falling. Both locations are expected to fall below flood stage late Sunday night or Monday. Slight rises are occurring on the Mississippi River north of the Quad Cities due to heavy rains to our north this past weekend. All of these rises will remain well below flood stage. A more active pattern returns to the area Friday night through next week with daily chances of showers and thunderstorms. This pattern may support locally heavy rainfall which could delay the rate of fall of flood waters on Rock River as well as new rises on other area tributary rivers. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ ...Corrected Long Term Discussion.. SYNOPSIS...Uttech SHORT TERM...Uttech LONG TERM...Cousins AVIATION...Sheets HYDROLOGY...Cousins
National Weather Service Kansas City/Pleasant Hill MO
704 PM CDT Thu May 21 2020 .Discussion... Issued at 349 PM CDT THU MAY 21 2020 The pattern we have been stuck in for almost a week now due to the stalled cut-off low to the east will finally end overnight. The first of many shortwave troughs we will see over the next week is currently located over eastern Kansas. This wave has helped develop elevated showers and isolated thunderstorms all day over that area. Induced ridging over our area on the east side of the mid-upper level cut-off low has stalled this feature most of the day, but is starting to break down as the low slowly shifts east. This may allow some elevated showers and a possible isolated thunderstorm to push into our area in the next few hours up until sunset. The area did get a small break in the lower clouds which is allowing our southwest counties up into the KC Metro to quickly heat up into the lower to mid 70s in the next couple hours before the mid clouds arrive. The next, more substantial, shortwave trough is currently exiting the Rockies creating multiple surface lows to form along the front range. CAM guidance is indicated a possible MCS pushing through our area tomorrow after sunrise with the start of that convection currently developing near the CO border now. Synoptically that solution looks favorable with a LLJ forming up shortly after sunset over OK and southern KS and strong WAA over eastern KS ahead of the low building MUCAPE ahead of the possible MCS. How far north storms will form over western KS will play a major factor in how much of our area will be impacted tomorrow morning. Forward and backward propagating Corfidi vectors indicate a E to NE motion for any MCS that would develop over eastern to central KS. With plenty of MUCAPE early on, a LLJ to help drive the motion, and favorable effective and 0-3km shear vectors the possibility of strong to severe storms just after sunrise over eastern KS is looking more likely. The main limiting factor would for our area would be how much MUCAPE would be available at arrival. The HRRR currently indicates around 800-1000 J/kg so it could be weakening or have become cold pool dominant as it arrives. Damaging winds would be the main threat with an arrival time around 9AM for our western counties. Due to the timing of this feature, our best severe weather chances now look to be earlier in the day than in the afternoon as we will have to recover from any cold pool draped over our area. There is still a chance this occurs over our southern counties, mainly south of HWY 50, in the afternoon. If we can get above 75F and recover and get MLCAPE values greater than 1000 J/kg then the second chance for severe is possible late afternoon on Friday. All modes would be on the table if this were to occur with a nice backed surface wind pattern and decent effective shear of 40kts. NAM4km and HRRR to hint at this occurring, but more than likely under estimate the cold pool effects on the backside of the MCS. Summer actually arrives to the area Saturday as a trough deepens over the western CONUS allowing strong WAA at all levels to push into the Plains. Not only will we get the warmer temperatures (mid 80s) we will open up the Gulf of Mexico and likely see some dewpoints in the upper 60s and lower 70s. This will make Saturday feel much warmer than it has recently with heat indices near 90 and something the public will not be acclimated too. Storms look to develop over Nebraska Saturday afternoon which could transition to an MCS Saturday night as a strong LLJ forms up over eastern KS. Model guidance differs slightly on just how far south the initial storms will form with NAM being further north, but if they can form up along the KS/NE border then our northern counties may see a MCS push through Sunday morning. High MUCAPE values (3000+ J/kg) would be available for any MCS to feed on as it propagates east, so this will be something worth watching as we get closer to Saturday night. As the long wave trough pushes east a cold front/stationary boundary will develop Sunday afternoon over central KS up through IA. This boundary will slowly shift to the SE over time, but will be the focal point for a more long duration rainfall event for the area. PWAT values will be near climatological maximums of 1.75" with a stalled SW-NE oriented boundary, multiple shortwave troughs, and storm motion along the boundary. This all sets up for possible flooding Sunday night into Tuesday morning as 2-3", possibly more with convection, fall over the Missouri River valley. How much rain we get Friday may contribute to the overall flash flooding potential so we will need to watch this as we get closer to the end of the weekend. && .Aviation...(For the 00Z TAFS through 00Z Friday Evening) Issued at 705 PM CDT THU MAY 21 2020 Expect low clouds to persist for the bulk of the forecast period, perhaps in and out of MVFR territory, and even some brief periods of IFR. Have opted for a more optimistic forecast for now, but can continue to monitor. Overnight light showers will be possible at the terminals, but thunder seems unlikely at this point, and prevailing rain also seems unlikely until a line of probably subsevere thunderstorms gets to the terminal around 14z-15z. Expect that to be a pretty quick round of prevailing rain with gusty winds and out of the terminals by around 18z. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ Discussion...Barham Aviation...Leighton
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
916 PM CDT Thu May 21 2020 .UPDATE... Quick forecast update mainly to adjust PoPs downward. It has been a quiet night across South Central Texas with only a few showers and an isolated thunderstorm forming across the Coastal Plains earlier this evening. The HRRR has trended drier with recent runs, while other mesoscale models do try to bring the thunderstorms ongoing to the northwest of our area around San Angelo towards the Hill Country later tonight. Think tonight should remain on the dry side, but have left some slight chance PoPs in mainly across areas along and west of I-35 to cover any of the storms to our west and northwest sneaking into the area. Trended all of the other hourly weather grids to match current observational trends. && .PREV DISCUSSION... /ISSUED 651 PM CDT Thu May 21 2020/ AVIATION... VFR conditions prevail across South Central Texas this evening. A few showers have popped up along the Coastal Plains, but these quickly dissipated. Convection across Mexico has remained well west of Del Rio. A few showers are still possible around San Antonio for the next few hours, before the lack of heating should dry everything out after sunset. MVFR and then IFR cigs will be possible along the I-35 corridor overnight tonight in the moist environment in place. VFR conditions will return between 14z-16z Friday morning. Isolated to scattered convection will be possible Friday afternoon but placement is uncertain so will not include mention in the TAFs at this time. PREV DISCUSSION... /ISSUED 313 PM CDT Thu May 21 2020/ SHORT TERM (Tonight through Friday Night)... An upper level trough covers the western half of the country with southwesterly to westerly flow over Texas. Surface winds were from the south keeping warm, moist air in place across our CWA. The boundary layer is conditionally unstable this afternoon and convection has already begun over the mountains in Mexico. Storms may form along the dryline farther north in West Texas and may move into our CWA later this evening. Although there is good instability there is a lack of forcing, so whether storms form is still questionable. If they do, they may produce large hail or damaging wind gusts. SPC has included the northern and western part of our CWA in the Marginal risk area for tonight. The upper trough will move slowly toward the east Friday. The airmass over South Central Texas will remain about the same and the forecast for Friday and Friday night will be about the same. There won`t be any strong forcing, but the atmosphere will be conditionally unstable. If storms can form, they could be strong. We will continue to carry slight to low end chance POPs. LONG TERM (Saturday through Thursday)... An active Memorial Day weekend through middle portions of next week is shaping up as we enter a wetter pattern. The period begins with a trough digging through the Rockies and Four Corners Saturday. Models are indicating a mid level disturbance, in the southwest flow aloft ahead of the larger trough, pivoting into the region during the day on Saturday and into Saturday night. There seems to be a signal that a complex of storms may form either to the west or northwest and move into the area Saturday night into Sunday morning. It`s difficult to say where exactly, and as we have seen lately mesoscale features, such as remnant outflow boundaries and MCVs, can wreak havoc on a forecast. The upper level trough eventually digs south through the southern Rockies Sunday and closes off over Northwest Texas Monday into Tuesday. From there a blocking pattern sets up through potentially the end of next week, with the low meandering over Northwest or North Texas. This places South Central Texas in an active scenario for additional rounds of showers and storms, with the potential for pockets of locally heavy rainfall given the anomalously high precipitable water values forecast. It is extremely difficult this far out to pinpoint timing and locations of these rounds given some of the mesoscale reasons already listed and subtle difference in the placing of the larger scale features with the global models. Although there does appear to be another signal Monday night into Tuesday, where a slow moving cold front could focus heavy rainfall. We are currently messaging the following: 1) Multiple rounds of showers and storms are possible over the Memorial Day weekend through the middle portions of next week. 2) Stay "Weather Aware" and check the forecast often through the Memorial Day weekend as details become clearer. 3) There will likely be a few rounds of strong to severe storms in addition to pockets of heavy rainfall which could lead to flooding 4) Forecast confidence is low on the timing of these sounds of storms. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 91 72 89 74 88 / 20 20 30 10 30 Austin Bergstrom Intl Airport 91 71 89 73 88 / 20 20 30 10 30 New Braunfels Muni Airport 91 71 89 73 88 / 30 30 30 10 30 Burnet Muni Airport 89 70 88 71 85 / 30 20 20 10 30 Del Rio Intl Airport 96 74 93 74 92 / 20 20 20 20 30 Georgetown Muni Airport 90 72 89 72 88 / 20 20 30 10 30 Hondo Muni Airport 92 73 90 73 91 / 30 20 20 20 30 San Marcos Muni Airport 91 72 89 72 88 / 30 20 30 10 30 La Grange - Fayette Regional 89 74 90 74 90 / 10 30 30 10 20 San Antonio Intl Airport 93 74 91 74 89 / 30 20 30 20 30 Stinson Muni Airport 92 73 92 75 90 / 30 20 30 20 30 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term/Aviation...Treadway Long-Term...BMW
Area Forecast Discussion
National Weather Service Grand Forks ND
1009 PM CDT Thu May 21 2020 .UPDATE... Issued at 1009 PM CDT Thu May 21 2020 A few showers are still lingering over the far northern Red River Valley, while additional showers are starting to develop over north central SD. It still looks like isolated to possibly scattered showers should redevelop into our area overnight before transitioning mainly into west central MN. There is enough lingering instability than an isolated thunderstorm can`t be ruled out, and we have seen activity on GOES-East GLM at times this evening. Amounts are still expected to be ling (0.1" or less where showers track), so impacts will be minimal. UPDATE Issued at 649 PM CDT Thu May 21 2020 Light returns on radar have mainly been associated with virga, though there have been a few reports of light rain (likely sprinkles). RAP analysis still shows 250-500 J/KG MUCAPE, so it`s not impossible to think a stray thunderstorm could develop along surface trough axis/stationary front before sunset, but so far it looks like we are approaching a "lull" in activity and mainly non-measurable precip (no impacts). Better coverage of measurable may arrive later tonight as previous forecast reflected (west central MN). Besides matching near term trends I held off on a major overhaul to current short term forecast, and will continue to monitor. && .SHORT TERM...(This evening through Friday night) Issued at 325 PM CDT Thu May 21 2020 Near term concerns will be confined to low rain chances and temps. Will continue to see increasing moisture with southerly winds into the evening as 925mb 30kts persists. Weak mid level convergence area within the mean flow evident on area radars with elevated returns may allow additional development of showers or storms this evening across eastern ND. CAMs suggesting that possibility though seeming more and more unlikely will keep a slight mention in the forecast for the evening. Friday morning model guidance brings another area of mid level coverage northward into MN though model QPF continues to decrease will have lowered pops from likely to chance. Will see more clouds Friday morning with lows held up into the upper 50s to near 60 tonight. Friday afternoon and evening a gradual shift to the east with shower activity is expected with an isolated chance for showers or a thunderstorm to redevelop in the valley and across eastern ND. Precip amounts will be light generally a tenth of an inch or less. .LONG TERM...(Saturday through Thursday) Issued at 325 PM CDT Thu May 21 2020 Weather-related impacts are possible this weekend. For the holiday weekend, look for highs in the 70s and 80s for Saturday with 70s on Sunday. Looking at the synoptic setup, H5 low pressure, situated in northern Saskatchewan, will bring a theta-e gradient boundary across the CWA Saturday night. Preceding this, we expect a chance for showers and thunderstorms during the afternoon. Modest instability and shear will allow for a conditional threat of severe thunderstorms, most likely starting in central North Dakota, then progressing eastward through the afternoon and evening. Another H7 low develops and moves across the Intermountain West late Saturday evening. This will impact the area on Sunday with another round of showers and thunderstorms. Ensemble guidance brings good agreement to the overall pattern, but not to the instability profile both Saturday and Sunday. For Memorial Day, remnant shower and thunderstorm activity is possible through the first half of the day for eastern North Dakota, and through the early afternoon for our Minnesota counties. Overall, Monday will be an improvement as far as precipitation is concerned, with highs generally in the lower 70s across the entire region. Overall, weather-related impacts will be minimal on Monday. Nearly zonal flow prevails Tuesday and Wednesday, with an ensemble signal for a trough passage as we head into Thursday. This will give us a good chance at dry weather both Tuesday and Wednesday, with highs in the 70s to near 80 degrees. Precipitation chances increase Wednesday evening through late Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 649 PM CDT Thu May 21 2020 Virga and possibly a few light showers will continue to move across eastern ND into northwest MN (very low coverage/impacts). We can`t rule out an isolated thunderstorm, but so far this isn`t not favored and chances/coverage do not warrant inclusion in TAFs. Another round of light showers may develop into Minnesota later tonight, but better chances would remain south of our TAF sites. Strongest winds gusts will diminish early in the TAF period and while winds will increase some Friday after sunrise the strongest gusts would be 17-21kt (much lower than previous days). MVFR conditions will once again overspread with good low level moisture lingering across the region late tonight, before VFR returns midday Friday. Isolated pockets of IFR conditions can`t be ruled out in eastern ND 10-14Z, but confidence in ceilings lower 1000 KFT AGL is low at this time. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...DJR SHORT TERM...JK LONG TERM...Lynch AVIATION...DJR
Area Forecast Discussion
National Weather Service Huntsville AL
928 PM CDT Thu May 21 2020 .NEAR TERM...(Rest of tonight) Issued at 928 PM CDT Thu May 21 2020 Widely scattered light-moderate shower activity associated with a cutoff upper low that has been situated across the region for the last couple of days continues to dissipate rapidly this evening. However, as the cutoff low tracks slowly northeastward into the Upper-OH Valley overnight, a weak mid-level shortwave disturbance (currently across the southwestern AR) will become absorbed in its circulation and accelerate northeastward, initiating the development of deep convection along a warm front positioned across central portions of MS/AL. Latest hi-res guidance suggests that this will occur in the 06-08Z timeframe, with showers and thunderstorms spreading northeastward into the local area between 08-12Z. Forecast soundings depict a favorable combination of deep-layer bulk shear in the 35-40 knot range and veering flow in the 0-3 km layer to support organized storm structures during this period. That said, it appears as if updrafts will be slightly elevated, and will likely not begin to tap into the more unstable surface-based airmass until the 12-18Z timeframe. Thus, we feel that a few strong storms capable of producing frequent lightning, small hail and brief gusty winds up to 40 MPH will be the main impacts early Friday morning. Otherwise, the remainder of the forecast grids appear to be on track at this point, although low temperatures have been increased slightly to account for current trends and a gradual increase in low-level moisture after Midnight. .SHORT TERM...(Friday through Saturday) Issued at 233 PM CDT Thu May 21 2020 As the warm front lifts into north AL, a plume of more unstable and moist air in the warm sector should enable upscale growth of clusters of ongoing convection. Deep layer bulk shear vectors will remain rather modest at 25-30kt, but with CAPE values approaching 2000-2500 J/Kg by midday or early afternoon, continued development of at least scattered thunderstorms along the warm front and/or outflow boundary will persist into early evening before shortwave ridging aloft builds in. The HRRR suggests the greatest risk during the midday and early afternoon hours, while the WRF suggests an early time with less certainty on the later convection. In either case, the combo of strong instability and modest shear may yield strong to perhaps a couple of severe thunderstorms in these clusters Friday. There appears to be a nocturnal uptick in redevelopment of convection by the models late Friday night due to a southwesterly LLJ/increase impinging possible residual outflow from earlier in the day. So will account for this as suggested blends indicate. On Saturday, the ridging at 850-500 mb shifts just east of AL/middle TN. The models indicate a very summer-like look to the synoptic fields with no capping and moist unstable air in place. Weak MCVs are abound in the model data, and should see another afternoon max of scattered deep convection. Highs will warm into the l-m80s Saturday afternoon. .LONG TERM...(Saturday night through Wednesday) Issued at 233 PM CDT Thu May 21 2020 There is pretty good confidence that the long wave pattern in the long term portion of the forecast will be characterized (initially) by an upper trough in the Intermountain West and a building ridge along the East Coast. The global suite of models including ensembles indicate the upper trough is likely to become closed off from the polar westerlies early next week, while the TN Valley will probably be situated along the western flank of the upper ridge in the East. So, while confidence is pretty decent on the large scale features and upper wave pattern through about mid-week next week, there is relatively low confidence in specific timing and impacts of the smaller scale features. What is evident is a potential number of short wave troughs that ride generally northward across the region during this period along the trough/ridge interface. Among the most noticeable of these may cross the area on Sunday, bringing a round of showers and thunderstorms to the area at that time. Given the lack of strong flow aloft and thus shear as well, very little storm organization is expected. Although, the presence of weak steering currents, moderate CAPE values and moderately high PWs will present a threat for some locally heavy rainfall and gusty winds where stronger cells do occur. Looking a little further ahead, the next short wave (albeit subtle) may round the west side of the upper ridge and into our area on Monday. Overall impacts from shower and thunderstorm activity look similar to that on Sunday, with continued weak shear present. High chance to likely POPs have been carried for most areas on these two days. The pattern may ultimately continue unabated perhaps even into the end of next week, with the possibility that the upper low will at least partially close and meander across the Southern Plains, while the upper ridge holds on strong to our east. This would tend to keep the region in southerly flow at/near the surface and ensure generally warm/humid conditions throughout. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 656 PM CDT Thu May 21 2020 VFR conditions will exist at the HSV/MSL terminals overnight, with a scattered layer of stratocu based arnd 3500 ft AGL beneath broken altostratus. The stratocu layer will slowly become broken during the early morning hours on Fri, as a warm front begins to approach the region from the southwest. Lift to the north of the warm front and to the east of a mid-level disturbance approaching the TN Valley should result in an initial increase in convection invof the terminals btwn 08-10Z, with TSRA becoming fairly widespread btwn 13-19Z, when PROB30 groups have been introduced for TSRA and MVFR cog/vsby reductions. Storms will shift northeastward with the warm front during the afternoon, with conditions improving at the airports btwn 17-19Z. Winds will veer to SSW and increase to arnd 10 knots in the wake of the warm front. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...70/DD SHORT TERM...17 LONG TERM...KDW AVIATION...70/DD For more information please visit our website at
Area Forecast Discussion
National Weather Service Lincoln IL
926 PM CDT Thu May 21 2020 .SYNOPSIS... Issued at 330 PM CDT Thu May 21 2020 Weak high pressure in the eastern Great Lakes will finally allow for a little bit of sunshine across the Midwest on Friday. This will allow temperatures to climb to more seasonal levels in the lower to middle 70s. A weather disturbance from the Plains will move toward the Great Lakes region Friday night, bringing us our next chance for showers and thunderstorms. The holiday weekend outlook has much warmer temperatures in store for central and southeast Illinois, along with periodic chances for a few thunderstorms. && .UPDATE... Issued at 924 PM CDT Thu May 21 2020 A corridor of clearing has developed in the clouds across our eastern counties, but HRRR and RAP guidance are indicating clouds from our SW area will begin to shift northward the rest of the night. Breaks will still be present, so some fog could begin to form due to the light and variable winds. The models are not jumping on the fog bandwagon just yet, but our recent period of rainy conditions could manifest in some fog later tonight. Went ahead and added fog as a result. Drizzle is the other concern tonight, with our NE counties having the best chance of being under the lower ceilings and light synoptic lift. Most areas should remain dry, so very minimal impact even if some patchy drizzle does occur. Updated sky and weather grids as needed to match those trends/possibilities. && .SHORT TERM...(This evening through Friday) ISSUED AT 330 PM CDT Thu May 21 2020 The pesky upper low which has plagued our area with periods of rain, clouds and cool temperatures is finally losing its grip on our weather. Early this afternoon the upper low was centered in western KY. An upper level shortwave in the central Plains is expected to lift toward Iowa Friday night, which will help kick the upper low eastward. An increasing southerly flow on Friday will result in more seasonal high temperatures in the mid 70s along with more breaks in the clouds from late morning into the afternoon. .LONG TERM...(Friday night through Thursday) ISSUED AT 330 PM CDT Thu May 21 2020 A rather active weather pattern is in store for central and eastern Illinois from this weekend into the middle of next week with above normal temperatures and periodic chances of showers and t-storms. An upper level ridge is expected to build along the Appalachians in the wake of the departing upper low. Upper level troughing will deepen in the Plains late this weekend, before cutting off from the upper level flow by midweek. This will keep us in a deep south to southwesterly flow through the long term period. The most noticeable feature will be daily high temperatures well into the 80s with higher levels of humidity, which will be quite the contrast from the recent cool, damp weather. The highest potential for showers/t-storms this weekend will be Friday night into Saturday morning with the short wave lifting northeastward and low level warm advection, and again on Memorial Day as the upper ridge axis shifts east of the state. On Sunday, we cut way back on the PoPs due to the proximity to the upper ridge and warmer, capping air aloft. With enough sun and warm low level temps, Sunday looks to be the warmest day of the year thus far with highs possibly reaching the upper 80s in spots. For Tuesday through Thursday it will difficult to time subtle shortwaves to provide forcing for thunderstorms as we remain in a warm sector with high instability but low shear. There is somewhat general agreement that Tuesday and again on Thursday the higher chances for convection may occur, but the confidence is quite low this far out. Highs in the lower/middle 80s with lows in the middle/upper 60s will definitely make it feel like summer has arrived. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 632 PM CDT Thu May 21 2020 Brief VFR conditions will occur across central Illinois this evening, before ceilings drop back to MVFR later tonight, and possibly even IFR in eastern IL. MVFR fog will also be possible, as surface winds become light and variable amid increasing surface dewpoints. We can`t rule out some patchy dense fog, but confidence is low that fog that thick would affect any TAF site. The upper level low is expected to finally get a kick to the east on Friday ahead of an approaching shortwave trough in the central Plains. This will allow for some breaks in the clouds, although the majority of the morning hours will remain at MVFR levels across central and eastern IL. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SYNOPSIS...Miller SHORT TERM...Miller LONG TERM...Miller AVIATION...Shimon
Area Forecast Discussion
National Weather Service Lubbock TX
617 PM CDT Thu May 21 2020 .AVIATION... Iso TS possible in the first few hours of the TAF period at KCDS and will monitor for inclusion of a mention. Otherwise, VFR conditions are likely through Friday. && .PREV DISCUSSION... /issued 230 PM CDT Thu May 21 2020/ SHORT TERM... Flow aloft has become more southwesterly in response to a large upper level low encompassing much of the western CONUS. At the surface a lee-side low has begun to develop in northeastern NM with surface winds turning southwesterly across the western portions of the CWA. This flow will advect warm dry air across the area and warm high temperatures into the 90s. Thanks to the SW flow aloft and at the surface the dryline is more east today and somewhere near the edge of the Caprock Escapement. To the east of the dryline afternoon convection will be highly conditional while west fire weather will be the main concern. Capping, the lack of mid-level moisture and missed timing of the upper level shortwave moving eastward will all limit chances for dryline convection this afternoon. However, forecasted MUCAPE values are over 2000 J/kg with shear values near 40 kts and steep low-mid level lapse rates all suggest that if a parcel can persist through the dry environment severe thunderstorms with rotation will be possible. Steep lapse rates and DCAPES over 1000 J/kg suggest that strong wind gusts up to 70 mph and large hail up to 2 inches will be possible. Additionally, a tornado risk can not be ruled out given the presences of an increasing low level jet this evening and increased EHIs. The HRRR is now showing a few possible storms across the far southeastern counties where better dewpoints will reside. Current satellite pictures are showing small cumulus fields develop just along the dryline but, the CU come down as fast as they go up leading us to believe the mid-levels may be in- fact too dry. We have gone ahead and lowered PoPs across the Rolling Plains into the slight chance category but not eliminated them. It is mid May and as the past few days have illustrated severe weather is possible no matter what. Tonight into tomorrow should be relatively quite weatherwise. A weak front will be forced into the northern portions of the CWA early tomorrow morning as an upper level storm moves through the High Plains. This front will do little in the way of affecting our area except for shifting the winds to the north for the first portion of the day. By tomorrow afternoon, W-SW surface flow returns with dry and warm weather. LONG TERM... The western trough that is currently in the process of reloading, will eject across the northern High Plains late Sunday, while a portion of it digs southeastward through the Four Corners region. The more southern energy is forecast to close off into a cut off low, potentially hanging out over or near West Texas through much of next week. Before this occurs, a dryline will be vacillating within the South/Rolling Plains the next few days, beneath westerly to southwesterly flow aloft. The dryline will be joined by a weak cold front that may dip into the CWA tomorrow, in response to a shortwave trough swinging by to our north early in the day. Either the dryline, or the triple point will probably be positioned somewhere near the far southeast corner of the CWA tomorrow afternoon/evening, where it could provide sufficient focus/forcing for late-day CI. Should storms develop, very strong instability and sufficient wind shear would support a definite severe weather risk. Saturday will bring more of the same, but the dryline is expected to be further west in response to backing flow aloft and dropping pressure in the lee of the central/southern Rockies. Hence, the conditional severe weather risk will encompass the eastern half or two thirds of the CWA Saturday afternoon. Sunday`s setup will be fairly similar to Saturday, except that the approaching western trough will provide more favorable upper level dynamics, make convective development more likely during the afternoon/evening. Again, environmental parameters will be solidly supportive of a severe weather risk along and ahead of the dryline. The northern stream portion of the system will send a cold front southward, though most guidance now delays its arrival until Monday. Depending on the timing of the front, this could provide an additional focus for storm development early next week. After that, it is beginning to appear more likely that the developing cut off low will linger overhead or nearby through much of next week. If this proves true, much/all of next week would be relatively cool and moist with periodic chances of showers and generally sub- severe thunderstorms. FIRE WEATHER... West of the dryline conditions will be favorable for fire weather as flow aloft and at the surface become SWRLY with the development of a lee-side surface low this afternoon. The warm/hot, breezy and very dry southwesterly winds will create elevated to briefly critical fire weather. Where rain hasn`t fallen in the past few days, across the western South Plains and far southwest Texas Panhandle, fuels will be more receptive to fire starts. Thus, an RFD has been issued roughly along and west of a Friona to Olton to Brownfield line, valid from noon until 9 PM. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 07
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
934 PM EDT Thu May 21 2020 .SYNOPSIS... Low pressure over the Carolinas will slowly move north towards the Chesapeake Bay through Friday night, then move east out to sea. High pressure builds into the region Saturday through Memorial Day and persists through mid-week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 01Z regional radar shows scattered showers, some heavy, moving through the north-central Virginia Piedmont. KCHO ASOS reported 0.21" between 00-01Z. These showers are moving towards the NW as surface low pressure over the Carolinas starts moving north towards the Chesapeake Bay region overnight. Convective activity ongoing attm over central NC in unstable air is expected to stratify as it crosses the VA/NC border. This should continue to move NW, and provide the piedmont with additional rainfall overnight. The FF Watch was cancelled earlier this evening after analysis and trends of the 12Z EPS, the HRRR trends, and the 12Z HREF. One-hour and 3-hr FFG seemed to be too high of a bar to support flash flooding overnight, especially on the stable side of the surface low. Ironically, the instablity does work it`s way into the southern part of the CWA before dawn, but it comes in after the end time of the cancelled watch. At that time, it is believed that any convective elements will be isolated and elevated, and there would be enough time to allow drainage from the previous rainfall. However, I did include thunder in the forecast for the southern waters of Maryland`s Chesapeake and St. Mary`s County. Thunder may have to be expanded up the I-95 corridor in and around Fredericksburg. Otherwise, the story overnight will be showers increasing in areal coverage across the entire CWA as stronger convective elements in the unstable air mass over NC moves into the more stable air north of the VA/NC border. Overnight low temps will be milder than normal, with dewpoints in the mid 50s on E/SE fetch originating over the Gulf Stream off Cape Hatteras. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Upper level low and surface low will be moving into the Mid-Atlantic through the day Friday. A band of rain will still be over our area during the first half of the day Friday as it progresses north and east along with the upper level low. As this rain band moves away and clouds break west of it, along with some instability and lift, could see a few thunderstorms developing Friday afternoon, mainly over Central Virginia and the Potomac Highlands. High temperatures will be between the mid 60s and upper 70s. Surface and upper level lows will move east and offshore on Friday night, but a chance of rain showers remain. Low temperatures will be in the 50s and 60s. Upper level low will be pushing offshore early Saturday as conditions continue to dry over our area, however upper level energy behind this system and some instability could produce afternoon thunderstorms on Saturday. High pressure will start building over our region Saturday night along with ridging aloft. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Mid to upper level ridging will take hold the second half of the holiday weekend as surface high pressure off the New England coast stretches a ridge down into the Mid-Atlantic region. As ridging begins to build, some linger upper level energy could be enough to spark some afternoon showers/storms across the Potomac/Allegheny Highlands. Otherwise, dry conditions and temperatures in the low to middle 70s expected. Continued dry conditions for your Memorial Day and into Tuesday as the upper ridge crests over the Mid-Atlantic and the ridge of high pressure remains strong over the Eastern Seaboard. Temperatures and humidity will tick upwards given southerly flow around the high to our east. With diurnal heating and increasing moisture, our mountain zones will reside on the western fringes of the surface ridge, with low end chance showers/storms possible both Monday and Tuesday afternoons. Better chance of rain comes Wednesday afternoon and evening as the high to our east nudges further eastward into the Atlantic and a weak shortwave tracks to our north. Temperatures will rise into the 80s with dewpoints in the 60s, so a bit better ingredients to support higher shower/storm chances during this time. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... IFR to LIFR due to VSBYs and CIGS are expected at all terminals after midnight, lasting well into Friday morning. Conditions will improve to VFR late on Friday with a chance of showers remaining, maybe a TSRA and a passing showers into Friday night. VFR on Saturday with afternoon TSRA possible. VFR conditions expected to persist at the terminals Sunday through Memorial Day as a ridge of high pressure at the surface and ridging aloft take hold. Winds will remain light and out of the ESE at less than 10 knots. && .MARINE... Winds will be below SCA threshold overnight under a strong inversion of warm air over colder water. Winds will become NW on Saturday through Saturday night. High pressure building at the surface and aloft will maintain sub SCA conditions over the waters Sunday through Memorial Day as light east southeast winds prevail. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...Lee NEAR TERM...Lee SHORT TERM...IMR LONG TERM...BKF AVIATION...Lee/BKF MARINE...Lee/BKF
Area Forecast Discussion...CORRECTED
National Weather Service Springfield MO
900 PM CDT Thu May 21 2020 .SHORT TERM...(This afternoon through Friday morning) Issued at 301 PM CDT Thu May 21 2020 Early this afternoon, a cut-off upper level low is spinning in place across the lower Ohio River valley due to being situated in a Rex block pattern. As a result, some broken low level cloud cover is lingering across portions of central Missouri and the eastern Missouri Ozarks, while portions of southwest Missouri have seen some mixed clouds and sunshine behind this feature. The Rex block will continue to break down the remainder of today as the cut-off upper low slowly drifts northeastward. However, a shortwave over Oklahoma is already making it`s way towards our area. Some instability and increasing moisture will continue to move in with this feature during the remainder of the afternoon and into the evening, keeping the ongoing scattered showers and thunderstorms going across southeast Kansas and western Missouri. This convection should diminish by mid to late evening as instability wanes towards sunset. No severe weather is expected with this activity. We should see a relatively quiet period tonight as more organized storm development remains to our west over portions of Kansas. CAM model solutions are coming into better agreement with decaying remnants of this overnight convection moving into southeast Kansas and western Missouri by the early morning tomorrow and pushing across our area from west to east throughout the morning hours. We can`t rule out a few damaging wind gusts and perhaps low end hail potential with this convection as it gets into western portions of our area, but it is expected to weaken as it moves across Missouri, as environmental instability decreases with eastward extent. .LONG TERM...(Friday through Wednesday) Issued at 301 PM CDT Thu May 21 2020 The threat for strong to severe storms tomorrow afternoon and evening will be dependent on how long the decaying morning convection remains in the area, as lingering cloud cover could hamper instability. However, the synoptic set up will still be favorable for more organized convection during the afternoon and evening given a low-level jet and sufficient deep-layer shear in addition to surface temperatures near 80 degrees and dewpoints in the 60s. CAM model solutions are still in some disagreement on the locations and storm modes of the forecast convection, with the NAM Nest hinting at a multicell cluster while the HRRR suggests a few supercells developing. Initiation during this timeframe will most likely be along a remnant outflow boundary from the morning storms. Any strong to severe storms that may develop would be capable of large hail and damaging winds, while the low end threat for a few tornadoes would mainly hinge on whether or not the storm mode is supercellular. The best chances for the severe thunderstorm risks will be across southeast Kansas and portions of western Missouri west of the Highway 65 corridor. The heavy rain threat for Friday will be best realized for locations where both the morning and later Friday round of storms move through. Generally speaking, around 0.5-1 inch of rain will be possible between the two rounds of storms, though isolated amounts upwards of two inches would not be out of the question in areas of training thunderstorms. Therefore, there is still a threat for flooding potential on Friday given this forecast rainfall falling on relatively saturated soils from last week. Saturday looks to be the "quietest" day of the coming weekend as some brief shortwave ridging will be in our vicinity between Friday`s shortwave and additional embedded shortwaves to our west in the southwest flow aloft. Significant instability will be present under this feature across the region on Saturday afternoon and evening, though shear and forcing for ascent look too marginal to support organized convection. Saturday will also likely be the warmest day of the weekend, with the entire region seeing high temperatures in the low to mid 80s. The second active period in the extended forecast will arrive on Sunday through Tuesday as the large-scale upper level trough finally approaches from our west, moving shortwave energy across the area and bringing daily showers and thunderstorms. Additionally, multiple medium-range models suggest this feature transitions into a cut-off low across the southern Plains and becomes separated from zonal flow over the northern CONUS during mid to late next week. This would keep the active, wet weather pattern lingering across the Missouri Ozarks through at least late next week if it comes to fruition. Overall, expect a widespread 2-3 inches of rain west of the Highway 65 corridor and 1-2 inches to the east, with locally higher amounts possible from training convection during the next 7 days. Additional flooding risks will be possible along with this heavier rainfall, as well. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 649 PM CDT Thu May 21 2020 Timing, coverage, and intensity of convection are the primary concerns for this forecast period. Models show scattered showers and storms starting tonight, with a line of strong to potentially severe storms moving west to east across the area Friday morning and early afternoon. Additional scattered showers and storms are possible behind that line. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Rothstein LONG TERM...Rothstein AVIATION...Titus
Area Forecast Discussion
National Weather Service Tulsa OK
941 PM CDT Thu May 21 2020 .DISCUSSION... Showers and thunderstorms that affected parts of northeast Oklahoma and far northwest Arkansas this afternoon and evening have just about moved out of the area at this time. A few isolated showers remain, but have lowered pops in some places for the rest of the evening. A developing MCS across southwest Kansas is expected to move east southeast into parts of northeast Oklahoma by around sunrise. The latest runs of the HRRR suggest scattered showers and storms will also develop later tonight out ahead of this complex across parts of the area, so have left pops alone for later tonight. Update on the way. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...23 LONG TERM....05 PLATE