Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/28/18

Area Forecast Discussion
National Weather Service Caribou ME
1034 PM EDT Sun May 27 2018 .SYNOPSIS... High pressure over the maritimes will move away to the east tonight and Memorial Day as a cold front approaches from the west. The cold front will cross the area Monday night. High pressure will build over the region on Tuesday and remain across the area through midweek. && .NEAR TERM /THROUGH MONDAY/... 1040 PM Update... IR satl imagery continued to show clouds on the increase w/the thickest cloud cover from the Central Highlands to the coast. Thinner cloud cover resides across the northern 1/2 of the CWA this evening but this will change by morning as the cloud cover advances and thickens. The latest runs of the HRRR and RAP supported some light rain showers making their way to the western and far nw area by sunrise. Kept the daycrew`s assessment of 20-30% POPs for these areas. Temps have dropped off into the 50s w/the exception of the immediate coast as readings were down in the upper 40s. Forecast temps of low to mid 40s for the CWA still look reasonable for overnight. Previous Discussion... Moisture wrapping around the high, and within a weak upper level shortwave ahead of the cold front, will spread clouds over the area late tonight into Monday. This will bring a mostly cloudy day on Monday with an increasing south southwesterly breeze. Some showers may stray ahead of the approaching cold front during the midday and afternoon. The best chances for showers will be across the north where some frontal convergence and upper level divergence will support lift. Any showers should be light. Highs Monday will range from the low 60s Downeast to the upper 60s over the north. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... A cold front mvg thru Mon night wl bring sctd showers to the region ovrngt, mainly acrs the north where best s/wv mvs acrs. Rmndr of the region wl see slgt chc-lochc pops drg the ovrngt, coming to an end by dawn as low tracks into the Gulf of St. Lawrence. Areas of fog ovr the water and patchy fog along the immediate coast wl be predominant drg the overnight hrs as low-lvl moisture streams in ahead of frontal bndry. As fropa occurs btwn 09z and 12z Tue fog should quickly erode. High pressure wl be building in from Canada Tue mrng as low departs to the east. This wl result in a mstly sunny day with gusty nw winds. Temps in the aftn rise to nr normal values for the north and abv normal ovr Downeast in the low 70s, especially with winds blowing offshore. Upr lvl ridge wl be building twd the east thru the middle of the week with 590 high centered off of the southeast coast. This brings an extended pd of nice, tranquil wx with mins nr to slightly blo normal under clr skies and lgt winds on Wed. On the flip- side highs wl be well abv normal with lwr 70s common acrs the St. John Vly and m/u 70s acrs interior Downeast. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Wed night and Thu wl feature sfc high sliding south of the area. Upr ridge conts to build thru Thur night bfr finally beginning to break down due to remnants of Alberto getting captured by wv mvg acrs the upr Midwest twd the end of the week. At this time there is just a chc of showers as the wv mvs thru late in the week and ovr the weekend. Temps on Thu wl lkly be the warmest of the week, especially to the north of the Bangor region. H9 temps increase to +20C and higher ovr interior sections of CWA and with full sun may see maxes appch m/u 80s acrs the far north. Coastal areas wl be kept cooler by onshore flow with some areas likely to crack 70F. H9 temps are progged to be warmer on Fri but with increasing clds and potential for showers expect maxes wl be several degrees cooler on Fri. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... NEAR TERM: VFR conditions are expected across the area tonight and Monday. SHORT TERM: VFR expected most of the week with the exception of Mon night as IFR fog develops along the coast with low-level moisture ahead of the frontal bndry. BHB most likely terminal to be impacted by IFR restrictions but potential exists for all terminals to get in on low MVFR/IFR restrictions Mon night ahead of cold front. && .MARINE... NEAR TERM: Winds and seas are expected to be below SCA through Monday. Some increasingly humid air moving over the waters on Monday may produce some light mist. SHORT TERM: Winds and seas will remain blo SCA levels through the middle of the week. Areas of fog are expected over the water Mon night into Tue morning before cold front crosses the waters. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Hewitt
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1154 PM EDT Sun May 27 2018 .AVIATION... Ridging will maintain VFR conditions and light winds throughout the upcoming forecast with just a small chance at shallow, patchy MVFR fog for a few hours early Monday morning. .DTW THRESHOLD PROBABILITIES... * None. && .PREV DISCUSSION... Issued at 334 PM EDT Sun May 27 2018 DISCUSSION... Changes to the forecast include increased PoPs today for the northern CWA with likely Pops for the Thumb between 21-02Z. Messaging to include conditional risk for strong to severe thunderstorms this evening north of I 69 with wind gusts to 60mph and 1 inch diameter hail possible. The area was upgraded earlier to a marginal designation for severe weather in midday Swody1 update. Noisy forecast again today with Southeast Michigan directly within the dirty summertime ridge. Difference today has been the development of CIN between 3.5-7.0 kft agl in response to a 825- 700mb anticyclone center pushing across far southern Lower Michigan. Satellite trends have supported this capping layer with very little cumulus development to this point. The anticyclone center is one of a very shortwavelength and presents an issue as midlevel theta e is progged to wash back in along the northern flank of the anticyclone center west to east directly into Saginaw Bay region yet this afternoon. The theta e axis is resolved by the NAM to be respectably deep from 900 to 700mb. This midlevel moisture in combination with strong late May insolation and an atmosphere preconditioned for deep mixing will likely lead to convective initiation in the higher terrain north of Saginaw Bay. Storm movement will be to the southeast at approximately 30 mph. Consensus of CAMS and high updraft probabilities in HREF output supports an increased confidence in thunderstorm activity from Saginaw Bay southeastward to Port Huron in the 21-02Z time window. Data supports a steeping of a convergence axis directly over northern cwa in response to slow to move deep ridging to the southeast. Uncertainty does with regards to magnitude of MLCAPES with model resolution/gradient issues in the northern Thumb. Current thinking is based on model soundings and RAP based mesoanalysis that at least 1500 J/kg MLCAPE will be available for thunderstorms this afternoon. 0-6km bulk shear of approximately 25 knots in vicinity of Lake Huron will be more than sufficient for storm organization. Thunderstorm activity this afternoon will be capable of wind gusts to 60 mph and hail to 1 inch. Farther south, including metro Detroit, models keep just enough CIN/capping to inhibit convective development. Some question with small amount of capping as skin layer dewpoints in the soundings do not invoke a lot of confidence. Certainly possible for thunderstorm activity over the southern cwa with the amount of instability within the column. Introduced entry level chance PoPs this evening, however, current data suggests thunderstorms will remain to the northeast of metro Detroit. A hot and muggy Memorial Day as the upper level ridge is forecasted to shear to some extent across the central Great Lakes. Yet again, forecast is all about the details with models now showing less focused anticyclonic vorticity advection for the state early in the day. To what extent is questionable as there is differences between Euro and NAM. Euro does show some AVA during the late day period. Regardless, will honor long days and maintain highs in the lower 90s. Question is again on thunderstorm potential as some CAM output is suggesting convective initiation over the higher terrain of Lower Michigan, pushing southward into the Saginaw Bay region. Overall pattern will be conducive for increasing low level deformation and backdoor front as likelihood for organized northeasterly anticyclonic flow increases during the evening. Given this potential trigger, and what should be steep low level lapse rates over the landmass of Lower Michigan continuing chance PoPs over the northern cwa. Low certainty in CAPEs with poor surface parameterizations, but the idea is for less instability on Monday given stronger background ridging signal. Backdoor front off of the lake is expected to become quasi stationary over portions of the cwa Tuesday. Net result is for cooler temperatures over the north half of the cwa with highs still expected to reach the upper 80s south of I 69. Relief from the muggy dewpoints will not arrive until a nocturnal release of the Lake Huron marine layer occurs Tuesday evening. Abundant tropical moisture associated with the remnants of Alberto will overspread the region on Wednesday. A cloudy morning will be followed by an increasing chance for showers and eventually more steady rainfall through the day and Thursday as PWAT values gradually rise to above 2 inches. Prolonged rainfall with periods of heavier rates expected with occasional embedded thunder possible. Highs will hold in the low 80s through both days. Widespread rain will be on the way out Thursday evening before potent upper energy (presently in the form of a cutoff low over the southwest CONUS) brings in another round of rainfall Friday. As this trough exits toward the Mid-Atlantic region, a cooler, drier, and more seasonable air mass will be ushered into SE Michigan for the weekend. MARINE... Winds will remain out of the south and light across the lakes today as a weak low pressure drops south out of northern Michigan and washes out. This will bring an associated frontal boundary across Lake Huron and shift winds out of northwest tonight and into tomorrow morning. Winds continue to remain light with favorable boating conditions for the most part today with the exception of decreasing areas of fog across inner Lake Huron and widely scattered storms this afternoon that may develop across west central Lake Huron down towards Saginaw Bay this afternoon. Mostly favorable boating conditions remain for the majority of Memorial Day as high pressure builds with a return to light southerly winds. Though, Memorial Day evening may see some scattered thunderstorms again as a frontal boundary drops southward. Weather conditions deteriorate midweek remnants of Subtropical Storm Alberto move towards the region. CLIMATE... Here is a list of record high temperatures for this holiday weekend. Monday, May 28th: Detroit 95 (set in 2012) Flint 93 (set in 2012) Saginaw/Tri-Cities 92 (set in 1977) && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....DG DISCUSSION...CB/TF MARINE.......AA CLIMATE......CB You can obtain your latest National Weather Service forecasts online at
National Weather Service Kansas City/Pleasant Hill MO
954 PM CDT Sun May 27 2018 .Discussion... Issued at 250 PM CDT SUN MAY 27 2018 Primary forecast focus is on continued hot and humid conditions. The story remains our unseasonably hot and humid conditions across the area. We actually broke the record high for St. Joseph at 11:24 AM, which was 93 F set in 2006, and through 2 PM it`s high was 98 F. The hottest temperatures remain focused at the leading edge of the upper ridge axis from southern and southeastern Nebraska into northeastern Kansas and northwestern Missouri, similar to yesterday. The Heat Advisory remains in effect for the Kansas City Metro area through 8 PM this evening. There remains a low chance a few thunderstorms may crop up along the very diffuse/weak surface trough in central Missouri. Latest HRRR and various flavors of the HiRes WRF have backed off quite a bit, with the WRF`s almost silent, with convection. Additionally, there has been little change in the cumulus development in eastern Missouri, with almost no development into central Missouri beyond the Columbia/Jeff City. However, it`s still worth a mention a storm or two can crop up given the uncapped, high CAPE environment, there`s just little to no focusing for ascent and little if any shear. For Memorial Day, it`s going to remain unseasonably hot, with afternoon heat index values holding in the mid 90s, overall. Will hold of on any Heat Advisory at this time, but the night shift may need to assess given potential impacts with it being a Holiday known for outdoor festivities. Messaging via social media and our web pages have advertised unseasonable heat and heat safety for several days now. Remaining hot on Tuesday, a negatively tilted 500mb trough will begin to approach the region, lifting off the central Rockies into the northern Plains through Tuesday. At the same time, the remnants of Subtropical Storm Alberto will be making it`s way north along the lower Mississippi Valley. Into early Wednesday, long range solutions are consistent with the Subtropical Storm formally known as Alberto being absorbed into the large trough as a mid-latitude cyclone over the joint Ohio-Mississippi Valleys. This will result in increased shower and thunderstorm chances across Missouri and eastward. This isn`t going to bring us much of a cool down, unfortunately, as highs remain in the upper 80s and lower 90s through the end of the week into next weekend. && .Aviation...(For the 00Z TAFS through 00Z Monday Evening) Issued at 954 PM CDT SUN MAY 27 2018 VFR conditions and light winds will prevail over the next 24 hours. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...Heat Advisory until 8 PM CDT this evening for KSZ104-105. MO...Heat Advisory until 8 PM CDT this evening for MOZ028-029-037-043. && $$ Discussion...Kurtz Aviation...Cutter
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
958 PM EDT Sun May 27 2018 .SYNOPSIS... High pressure over the maritimes will retreat well offshore tonight. Weak low pressure passing to our south tonight and early Monday will spread clouds across the entire forecast area. Any showers with this disturbance should be spotty and largely confined to far southern New Hampshire and the southern tip of Maine. Another low will pass to our north on Monday with a trailing cold front to cross the region Monday night preceded by a few showers across the mountains and foothills. High pressure will build over the region Tuesday and will push offshore south of New England Wednesday. Low pressure may bring appreciable rainfall to the region Friday into next weekend. && .NEAR TERM /THROUGH MONDAY/... 955 PM Update... Keeping an eye on the stratus and shower activity as it moves into southern NH. Diminishing the PoPs earlier in the afternoon update seems to have worked out with still some dry air to overcome in the lower levels per the 00Z KGYX sounding. Saturation should be improving in the atmospheric column as onshore flow adds more moisture to the air...and showers should be reaching the surface more as the night wears on. 617 PM Update... Minor changes to the forecast for PoPs and sky cover. Otherwise minor changes as precipitation edges into the southern sections of the forecast area this evening. HRRR and other CAM models showing only a few cents worth of QPF so have kept PoPs low. Drizzle and fog likely offshore with stratus moving in and becoming a nuisance along the shore and a bit inland. Previous discussion... At 18z...a 1028 millibar high was over Nova Scotia. A wavy frontal boundary extended from south of Long Island through the DELMARVA region. GOES imagery showed the cloud shield ahead of a weak impulse and associated surface wave overspreading the remainder of the forecast area at the moment. An area of showers across western New England were creeping eastward and will graze southern and western sections of the forecast area through early tonight. Onshore flow between the retreating maritimes high and the disturbance to our south will complicate matters as it may produce some low clouds and patchy fog for coastal and southern areas overnight. && .SHORT TERM /MONDAY NIGHT THROUGH 6 PM MONDAY/... Slow improvement Monday as clouds decrease from west to east behind the departing disturbance and the flow becomes more southerly. There may be some lingering low clouds east and north of Casco Bay until early afternoon as the trajectory remains onshore. Otherwise...becoming partly sunny by afternoon with highs ranging from around 60 on the around 70 inland. Low pressure will be passing by to our north across Quebec Province late tomorrow and tomorrow night with the trailing frontal system producing a few showers across northern and mountains sections. Those showers will quickly end tomorrow night as high pressure builds in from the northwest. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... A cold front will be departing offshore Tuesday morning. High pressure moves in during the day on Tuesday and moves across the region Wednesday. On Tuesday, despite the morning cold frontal passage we`ll still warm up well into the 70s and 80s across the region. High pressure will settle across the forecast area Tuesday night. With light winds and dry air in place, we should see good radiational cooling. Some of the best radiators in northern NH will likely see lows in the 30s Tuesday night. Frost advisory not completely out of the question. High pressure slides offshore on Wednesday allowing for moistening return flow. This will likely keep the coast cooler on Wednesday. However, it will remain dry. The remnants of Alberto approach Tuesday and may bring some beneficial rains to the region Thursday night through Saturday. However, early indications are that this period will not be a washout. It`ll feel more summery/tropical though with dewpoints likely getting well into the 60s with showers and thunderstorms from time to time. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Short Term /through Monday night/...VFR gives way to MVFR tonight in cigs with lcl IFR in -dz and fog and sct -shra. On Monday...improving to VFR throughout btw 15 and 18z with sct MVFR aft 20z in mtn -shra. Long Term...VFR conditions expected Tuesday through Thursday. Could see lower conditions develop Thu night and Fri with increased tropical moisture expected. && .MARINE... Short Term /through Monday Night/...Marginal SCA winds gusts continue through early evening otherwise SCA seas for the balance of the night into the day Monday. I`ve extended the SCA through late tonight and expect it`ll be extended into the day on Monday for hazardous seas. Long Term...Conditions are expected to remain below SCA thresholds Tuesday through Saturday. && .FIRE WEATHER... Moist onshore flow will continue into Monday. The rest of the week looks warm, with light winds, and moderate humidity. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 6 AM EDT Monday for ANZ150-152-154. && $$ NEAR TERM...Hanes SHORT TERM...Schwibs LONG TERM...Ekster
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
915 PM CDT Sun May 27 2018 .UPDATE... 915 PM CDT Incredible heat for late May continues with some of the hottest weather ever in this region for May. Chicago tied for 2nd place for hottest May day on record (records in Chicago go back 1871). The 00z sounding from DVN had a 925mb temps of 28.8C which using SPC`s sounding climo shows that this is a record warm 925mb temp for the month of May (and June!!). The RAP/HRRR continue to perform well with the unseasonable heat and did a pretty good job last evening with today`s highs. The RAP has fairly widespread upper 90s, a couple degree warmer than today, for Monday. Other models have 925mb temps about 1C to 1.5C warmer tomorrow than today, so potential is definitely there for widespread upper 90s and perhaps even a couple spots tagging the century mark Monday. Have adjusted high temps up a couple degrees over most of the CWA for Monday, with the one exception being the Chicago metro area. The reason I opted not to raise temps over the Chicago metro for Monday is the potential for an earlier (and stronger lake breeze than today). A couple models have been developing a fast moving MCS tracking across the Upper Mississippi Valley with lake charged outflow from this MCS plowing in off the lake with strong NE winds and much cooler temps by early afternoon. This probably isn`t the most likely scenario at this time, but with the NAM and a couple other CAMs showing it, hard to discount the potential as well. Given the uncertainty wrt to a potential lake charged outflow cooling temps off Monday, have opted to just let going forecast ride. Should this early/strong lake breeze not materialize then high temps Monday would likely be around if not a degree or two higher than Sunday. Conversely, should this lake boundary being advertised by the NAM and friends pan out, then afternoon temps would likely be in the 80s in the metro area, with 70s probable at the shore. At this point, it would appear that convective threat should be just about over for this evening. With upper high right overhead Monday, the threat of isolated storms Monday looks even lower than today. - Izzi && .SHORT TERM... 304 PM CDT Through Monday... In an unseasonably warm airmass, but with modest dewpoints, temperatures are rising into the middle 90s across much of the region. With dewpoints still only 50s to lower 60s, temperatures have been able to rise more rapidly than typical diurnal warming rates with many areas seeing 90F before noon. In the weak pressure gradient environment, a lake breeze has formed, turning winds along the lake front to onshore, allowing temps to moderate along the lake front. The boundary should push inland far enough the bring some early cooling to the northern suburbs, but the south end of the lake breeze is making little inland progression and the southern portions of the Chicago Metro area will likely not be impacted. Otherwise, main concern for the afternoon and into the early evening is isolated thunderstorm development over central and far western portions of the CWA. Latest SPC mesoanalysis shows axes of enhanced CAPE in these areas, while far nern IL/nwrn IN remain a bit more stable. This idea is also noted in satellite imagery where the cu field is much more sparse. While severe wx is not expected in a weakly sheared environment, some cells have shown the potential to strengthen rapidly and and produce brief heavy downpours, with small hail possible. In the weakly sheared environment, storm motion is nearly stationary, with perhaps a slow south direction. so far this afternoon, any severe storms have remained south of the CWA, but an isolated severe storm cannot be ruled out this afternoon for the far southern portions of the CWA. Convection trends should be largely diurnal, with activity diminishing with sunset. Monday should, largely, be a case or wash, rinse and repeat as there will be little progression to the overall pattern. Other than perhaps a bit of debris cloud, mostly sunny, warm conditions are expected for tomorrow, with temperatures once again in the middle 90s. Lake breeze development is also likely again tomorrow, allowing for some cooling along the lakefront by early afternoon. && .LONG TERM... 337 PM CDT Monday night through Sunday... Relatively quiet conditions at the start of the period, with any precip development to the north tied to surface trough likely staying to the north. Shower/thunderstorm chances on Tuesday look to remain low, however, can`t rule out some isolated afternoon development. Another hot day is expected with high temps in the 90s likely over much of the area, with the exception of areas near the lake where onshore flow will be in place. Next precip chances Tuesday night into Wednesday will be tied to the approaching remnants of Tropical Storm Alberto. Although chances increase Tuesday night, highest chances arrive Wednesday when the system lifts through the region. Thunder will be possible during this time, and given the tropical nature of this system, will need to monitor higher rainfall potential. This system will linger during the middle part of the week, while another system approaches from the west. Although some variability with the evolution of this approaching system, could provide additional precip chances through the end of the work week. Temps on Wednesday will be cooler given the likely extent of the precip/cloud shield, with an additional day of cooler temps possible on Thursday. Rodriguez && .CLIMATE... 915 PM CDT The following are daily record highs for Chicago and Rockford for May 28th. Monday ------------------------- Chicago 95 (2012) Rockford 93 (2006) MTF/Ratzer && .AVIATION... For the 00Z TAFs... VFR conditions expected through the period, with light winds into Monday morning. The wind forecast becomes complicated late Monday morning into the early evening. An outflow boundary from convection across northern WI and the U.P. of MI overnight may surge far enough south to reach all of the terminals by noon Monday. If this were to occur, a 1-2 hour period of NNE wind gusting over 20 kts will be possible. If the boundary fails to reach northern IL, a lake breeze is still expected to switch winds to the east at or slightly above 10 kts by mid afternoon at ORD/MDW. Kluber && .MARINE... 345 PM CDT In the near term, there has been some fog reported over the lake. Given this possibility, have included fog in the open waters forecast for tonight. Winds over the lake don`t appear to be overly strong into the start of the week. Will see high pressure build south out of Canada by late Monday night into Tuesday, with a steadier northerly wind expected. By midweek, winds will likely be variable as the next system approaches from the south and moves across the lake. Rodriguez && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lubbock TX
605 PM CDT Sun May 27 2018 .AVIATION... VFR. Low level wind shear should affect all terminals toward midnight once surface winds slacken. Otherwise, Memorial Day should again feature some afternoon TS mainly NW-N of PVW. && .PREV DISCUSSION... /issued 237 PM CDT Sun May 27 2018/ DISCUSSION... This afternoon the upper level low has shifted east over Utah with the ridge axis shifted east as well over Oklahoma. A shortwave moving out of the Rockies is helping initialize showers along the dryline this afternoon. The HRRR handled the virga showers well this morning and has isolated showers and thunderstorms along the state line this afternoon. We are already seeing a few showers in Amarillo`s area, but expect a few further south in our area as well. Thunderstorms should be high based and high wind gusts are the main threat. Monday`s set up will be similar to today, with showers and thunderstorms possible out ahead of the upper low. Both the NAM and GFS show precip in the northeastern Panhandle, but the question will be how far south they extend. Have PoPs at a slight chance for our northern counties during the afternoon then shifting to the northern Rolling Plains Monday evening. The ridge will flatten as the upper low moves across the Northern and Central Plains early this week. This should decrease temperatures a few degrees to the upper 90s on Monday. Temperatures start to increase again on Tuesday and will continue to warm through the week. A heat advisory may be needed as highs will be 100-106 Wednesday and Thursday. Solutions are showing a weak front entering the northern Panhandle Wednesday, but have it stalling out before reaching the South Plains. The next wave will move across the Rockies to our north this weekend. The best chance of rain looks to be on Friday and Saturday evenings if there is enough moisture and we can break the cap. Both the ECMWF and GFS show a front moving through Sunday, which hopefully will bring some temperature relief. FIRE WEATHER... Hot and dry conditions will continue through the week. With south winds 15-20 mph, elevated fire weather conditions are expected this afternoon and Monday afternoon. A Rangeland Fire Danger Statement continues through this evening for the extreme southwest Panhandle and western South Plains. Isolated high based thunderstorms may also produce dry lightning and gusty winds this afternoon and Monday afternoon. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 93
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
1037 PM CDT Sun May 27 2018 .AVIATION... 28/06Z TAFs. VFR conditions expected to continue. Will not include any SHRA/TSRA in western Oklahoma terminals first part of forecast as activity over the panhandles continues to diminish. Gusty winds will be possible through mainly at KWWR. Will include PROB30 at KWWR for tomorrow evening with TSRA expected to impact at least far northwest Oklahoma late in the forecast period. Gusty southeast winds will be seen again tomorrow, especially western Oklahoma. && .PREV DISCUSSION... /issued 619 PM CDT Sun May 27 2018/ AVIATION... 28/00Z TAFs. VFR conditions expected with continued southeasterly winds. 15-25KT gusts again expected across western Oklahoma terminals again tomorrow. TSRA west of KWWR at issuance time expected to stay primarily west and north of KWWR, at least not high enough chance for TEMPO or prevailing mention. However, remnants may affect site with strong wind gusts and will amend as needed. PREV DISCUSSION... /issued 317 PM CDT Sun May 27 2018/ DISCUSSION... Convection has developed in the panhandles. The consensus in the high-resolution models is that the storms should become less widespread as they move toward northwest Oklahoma this evening, although the current storms are a little farther east than these models would suggest at this time and the RAP and mesoanalysis shows a nearly uncapped airmass in northwest Oklahoma right now, so will keep an eye on trends. Have kept POPs relatively low to begin with, but will watch for the need to increase if necessary. There is a higher chance for storms moving out of the high plains tomorrow night and moving into at least northwest Oklahoma overnight, but then focus shifts farther north with the ejecting shortwave so it may not continue very far east. Another complex looks to develop Tuesday evening in Kansas and brush across portions of northern Oklahoma. Otherwise, we just expect very warm to hot weather with low to zero precipitation chances through the remainder of the week. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 69 91 70 93 / 0 0 0 10 Hobart OK 72 94 72 98 / 10 10 20 20 Wichita Falls TX 72 94 72 97 / 0 0 10 10 Gage OK 71 93 69 96 / 20 20 40 20 Ponca City OK 69 93 71 92 / 0 0 0 10 Durant OK 70 90 71 93 / 0 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ 25/11
Area Forecast Discussion
National Weather Service Blacksburg VA
941 PM EDT Sun May 27 2018 .SYNOPSIS... High pressure centered offshore will maintain a moist southerly flow of air into the region for the next several days. Subtropical Storm Alberto moving into the Gulf of Mexico this weekend will move ashore and into the lower Mississippi Valley early in the week. Tropical moisture will stream north into the region making for very rain efficient showers and thunderstorms. && .NEAR TERM /THROUGH MONDAY/... As of 940 PM EDT Sunday... The bulk of the precipitation continues to be focused mainly along and north of Route 460. This trend will continue into the early morning hours of Monday. Meso-scale models continue to suggest this precipitation will dissipate within a few hours after midnight. Precipitation in advance of Alberto will start to spread north into the far southern sections of the region around daybreak Monday, however the trend has slowed. Have reflect this in the forecast during the forenoon hours on Monday. As of 655 PM EDT Sunday... The forecast through the evening hours has been updated to reflect a decreased chance of precipitation across the southern half of the region. The bulk of the precipitation will be situated along and north of Route 460 through midnight. After midnight, we are expecting a return of precipitation to the southern half of the region, especially as we approach daybreak Monday. As of 340 PM EDT Sunday... Scattered showers and thunderstorms have formed in the moist unstable air across our region with the better coverage across the higher terrain and along the Blue Ridge. Ample insolation has allowed MLCAPE values to climb to around 1500 to 3000 J/KG. The combination of upper trough over the northern Mid-Atlantic and tropical moisture streaming north from the Gulf of Mexico has resulted in a convergence axis along or north of our CWA border. With healthy PWATS, these storms will be very rain efficient rain producers. The HRRR and HiresW-ARW-East indicated that the greatest convection concentration will occur cross the northern half of our forecast area. The NAM and RAP generates precipitation across the entire forecast area. The GFS and ECMWF showers widespread storms with the heaviest north of our forecast area. The excessive rain fall had marginal potential across the entire forecast area with slight chance to our northeast across Washington area. We will need to watch for flooding issues across entire forecast area with deeper convection or training. The good news is that the storm motion is faster today around 15 knots compared to yesterday. One weak spots will be Tazewell county where some rain gages reporting 2-3 inch amounts Saturday. Attm will hold off on a Flash Flood Watch. Prefer to see where convergence boundaries will line-up and target those areas of high confidence as opposed to blanketing a larger piece of real estate. Low temperatures tonight will range from the upper 50s in the mountains to the mid 60s in the piedmont. Refer to the latest advisories from NHC on Alberto for track and its movement. Alberto comes ashore Monday morning and continues moving northward into southern Alabama by Monday evening. The flooding potential for Monday will depend on how much rainfall is accumulated from several days of locally heavy tropical rainfall and where the deeper convection forms. The greatest chances for showers and thunderstorms Monday will occur across southern portions of the forecast area. Decided to mention the rain could be heavy at times in the south. The Day Two excessive rainfall showed a sharp gradient with a slight chance to our south across North Carolina. Both the GFS and ECMWF showed richer moisture try to push into the southern edge of our forecast area before translating east to the coast. High temperatures on Monday will vary for around 70 degrees in the mountains to the upper 70s in the east. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 230 PM EDT Sunday... NHC forecasts bring Alberto ashore Monday morning and continues the center on a NNW track into southern Alabama by Monday evening while weakening the system to a tropical depression by Tuesday morning over north central Alabama. Forward speed then increases as the NNW track continues with the depression in southern Indiana by Wednesday morning and Michigan by Thursday morning. Our forecast area will remain in deep southerly flow through this entire period with extremely high moisture for late May. The 12z/27 RNK sounding PWAT of 1.42 inches is near `all-time` high for the date (1995-2014 SPC climatology) and chances are very good that this type of moisture remains over the region for next few days and beyond. As mentioned in previous discussions the forecast NAEFS anomalies for PWAT are 2 to 2.5 standard deviations above normal through much of the week. Bottom line is any showers that develop are will be efficient rain producers and storms that lingers over a particular location or small basin more than about 1-2 hours are liable to produce minor flooding and 2-3 hours could initiate flash flooding. Day 3 Excessive rainfall outlook from WPC shows Slight Risk (10-20 percent chance)for exceeding flash flood guidance 12z Tuesday through 12z Wednesday. This does not provide much confidence in issuing a Flash Flood Watch given the lack of focus and the shotgun pattern of flash flood guidance (FFG) in place across our region. 3-hour FFG ranges generally from 1.5 to 3.0 inches with the lower guidance mainly in the mountains. Will hold off on a Flood/Flash Watch as the pattern is too diffuse in terms of timing and location. A short-fused Watch targeted to developing organized convection may make more sense than what could be a 3-day (or longer) Watch. As Alberto lifts into the Tennessee Valley late Tuesday into Wednesday a Marginal Risk for Severe will exist with the possibility for isolated tornadoes in the northeast quadrant of the weakening system as well. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 300 PM EDT Sunday... A generally wet pattern is expected to continue late week into next weekend as the remains of Alberto lift northward into the northern Great Lakes. But then the forecast becomes interesting as 12z/27 GFS shows intense upper low over the western North Atlantic blocked by ridging south of Greenland. This forces the upper low over the Great Lakes back to the southeast with a broad area of low pressure over the Mid-Atlantic that deepens with time over VA/NC area providing continued chances for rainfall. The 00z/27 ECMWF shows similar longwave pattern with the Greenland block but develops surface low pressure somewhat further north and east, while 12z/27 CMC closer to GFS. Obviously pattern details cannot be descried with any real confidence at this range but the pattern certainly fits the definition of `unsettled` through the extended period. Used mainly Super blend for the grids during this time frame. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... As of 730 PM EDT Sunday... Showers and a few thunderstorms have been come concentrated across the northern half of the forecast region. Conditions are primarily VFR except under the heavier showers/storms. As the night progresses, look for fog to develop with visibility`s trending IFR/MVFR. Visibilities will improve to VFR around or a little after 13Z/9AM Monday. Precipitation will return to the region from the south on Monday as moisture streams north on the east side of Alberto. Winds will be calm or light and variable through the period. Medium confidence in ceilings, visibilities and winds during the taf period. .Extended Aviation Discussion... Wet pattern anticipated through the upcoming week with periods of at least diurnally driven sub-VFR conditions associated with deep convection. Moist low level southerly winds will also favor lower layers of cloudiness at night, especially along the spine of the Appalachians with potential for both MVFR Cigs and early morning MVFR visibilities from mist/haze. The tropical system over the Gulf of Mexico may begin to impact the region mid-week. The unsettled weather with showers and thunderstorms may continue into the end of the week. && .HYDROLOGY... As of 315 PM Sunday... Significant focus in hydro concerns as discussed in portion of the Near, Short and Long term discussions above. Alberto and associated effects will be with us through the upcoming week in one form or another. The question of Flood or Flash Flood Watches will be with us during much of this time period as mentioned earlier but the notion of holding onto what could be a very long-fused Watch seems almost counter to producing real awareness of any flood threat. There may be opportunities for more short-fused Flash Flood Watches tied to a more discernible threat such as banded features or persistent clusters of storms. That said, the ground is fairly saturated in many places but as noted above very erratic coverage. River flooding cannot be discounted especially on smaller fast- reacting streams such as the upper Roanoke, Watauga, or even something like Mason Creek. All basins will have to be monitored closely. The latest MMEFS ensembles, mostly from 00z/27 or 06z/27 are painting some a somewhat less robust response on the bigger rivers than the previous set of runs with minor to moderate flooding generally in the 30 percent or less chance in most large river basins. The experience with MMEFS has been that is tends to overdo the probabilities of reaching high stages at these extended forecast time periods. Still, the Dan River basin once again under the highest threat for flooding but that would be a late week time frame. && .EQUIPMENT... NOAA Weather Radio, All Hazards, WZ2500 at Wytheville, VA, broadcasting on a frequency of 162.45 mHz has been fixed. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...KK/PM NEAR TERM...DS/KK SHORT TERM...PC LONG TERM...PC AVIATION...DS/KK/PM HYDROLOGY...PC EQUIPMENT...DS