Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/13/18

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
525 PM MDT Tue Jun 12 2018 .AVIATION... 00Z TAF CYCLE Upper high center to meander around central and eastern NM next 24 hours as moisture slowly increases into the circulation. A few strong to severe thunderstorms until around 03Z over ne NM with wind gusts to 50 kt and large hail as they move to the northeast and east. These storms may produce an outflow boundary that pushes westward to the east slopes of the Sangre de Cristo and Sandia/Manzano mts and into the RGV, with the east wind impacting KSKX, KSAF and KABQ aft 03Z. Elsewhere over the higher terrain, isold to sct virga showers until around 03Z. Smoke may drift into nw NM aft 03Z, with some vsby restrictions until around 13/16Z. Expect isold to sct showers and tstms to redevelop over the higher terrain aft 13/18Z. && .PREV DISCUSSION...251 PM MDT Tue Jun 12 2018... .SYNOPSIS... Very hot temperatures will trend slightly cooler each day through Friday before a significant surge of moisture moves into New Mexico from the remnants of Hurricane Bud. A slight uptick in showers and storms will occur each afternoon before the highest chances move through Saturday. Temperatures will cool below normal with this moisture surge over the weekend. The focus for showers and storms will shift into eastern New Mexico Sunday and Monday while central and western New Mexico heats back up. Another large scale moisture surge is possible Tuesday and Wednesday as a strong back door cold front slides southwest through New Mexico. && .DISCUSSION... This latest forecast package will remain cautiously optimistic with regard to the extent of precipitation across the region through the weekend. Surface dewpoints currently range from the teens across eastern AZ and western NM to the 30s across the eastern plains. 700mb dewpoint depressions on the 12Z RAOB at KABQ were close to 50F. Expect one more night of comfortably cool low temps over central and western NM with strong radiational cooling and low humidity. The 12Z HRRR smoke run shows another impulse of smoke draining into the Four Corners region from the 416 Fire and valleys around the Gila region from the Buzzard and Willow fires. Convective coverage is shown to increase Wednesday by all model guidance including the 12Z HREF. Enough dry air will still be in place beneath the 592dm H5 high center to favor dry storms along and west of the central mt chain with a mixture of wet and dry across the eastern plains. The 12Z GFS shows a large mass of high clouds spreading north late Wednesday from convection that develops over the Sierra Madre ahead of Bud. This will be the first indication of deeper moisture that begins increasing Thursday and Friday. 12Z models and ensembles are in decent agreement Thursday and Friday that the upper high center will stretch into a ridge axis while drifting eastward into the Arklatex region. The 12Z NAEFS indicates the deeper atmospheric moisture advection will flow northward into Arizona Thursday and remain west of the Cont Dvd Friday. Models still note a westward extension of the ridge axis into NM both days so the coverage of showers and storms still appears to be lackluster for now. All eyes are on Saturday as the main trough axis associated with the remnants of Bud shifts eastward across NM. The GFS remains the most bullish with moderate to heavy QPF Saturday and Saturday night while the ECMWF and Canadian show precip coverage and intensity weakening as it crosses NM later on Saturday. Thus, while PoP values increased on model trends the forecast still remains on the conservative side. Guyer && .FIRE WEATHER... The center of anticyclonic circulation aloft will begin to shift east of NM through mid week as an upper level trough deepens on the west coast. This will allow better moisture to flow northward into the state with min humidities climbing a few to 13 percent Wednesday afternoon. Scattered to isolated showers and thunderstorms will result along the central mountain chain and across the NE plains, with more isolated activity in the west and northwest mountains. Cells out west will tend to be dry and gusty, except for a mixture of wet and dry cells in the mountains of Socorro County. Storms will mostly move toward the north and northeast at 10 to 20 mph. Dry or hybrid wet/dry microbursts may result in erratic wind gusts up to 50 mph near storms and virga showers. The improving moisture will cause high temperatures to fall a few to 7 degrees on Tuesday from today`s readings. Thursday through the end of the week the upper high will migrate over the Mississippi River Valley and broaden, while a low pressure system digs over the Great Basin. This will draw a surge of monsoon moisture north and northeastward across the forecast area with increasing shower and thunderstorm chances each day. Precipitable water (PWAT) values are forecast to rise above normal starting Thursday, then reach record values around 1-1.25 inches (by the GFS) on Saturday as the remnants of Hurricane Bud cross. Models vary on precipitation amounts, but it looks like the mountains and continental divide region may receive around 0.75 to 1 inch of rain during the latter half of the week. Many lower elevation locations should receive at least a quarter inch of rain, except for locations along NM`s eastern border where amounts will be less. The potential exists for flash flooding below burn scars, especially Saturday. In the wake of Bud`s remnants, drier air will filter over the state from the west with a significant downtick in convection Sunday and again Monday. Recycled moisture should allow mainly isolated showers and thunderstorms to redevelop in the west Sunday, while better moisture lingers in the east with scattered to isolated activity. The northern mountains and far easter plains will be favored for scattered to isolated storms on Monday, as a back door cold front enters the northeast with another shot of moisture. The back door cold front may push into western areas on Tuesday increasing precipitation chances there as well. High temperatures will drop to near and below normal as this early season burst of moisture arrives. 44 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Wakefield VA
949 PM EDT Tue Jun 12 2018 .SYNOPSIS... A warm front slowly returns back north late tonight through Wednesday morning then dissipates. A cold front crosses the area Wednesday night into Thursday to be followed by high pressure building over the region late Thursday through the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 950 PM EDT Tuesday... High pressure remains over the VA piedmont, with a trough off the NC coast. Scattered showers continue to stream nwd over coastal NE NC, SE VA, and the VA Ern Shore associated with this trough. Cloudy this evening with temperatures generally in the mid 60s to around 70F. Scattered showers are expected to continue from the VA Ern Shore through SE VA and coastal NE NC through midnight. The latest HRRR trends support a chc of showers shifting to the Nrn Neck and Middle Peninsula through the early overnight hours, then toward the MD Ern Shore late tonight through early Wednesday morning. A warm front slowly lifts back N late tonight resulting in stratus and some fog. Expecting mainly stratus, with the best potential for fog over s-central VA and interior NE NC. Lows tonight will mainly be in the low 60s NW to 65-70F elsewhere. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... As of 315 PM EDT Tuesday... Frontal boundary dissipates over the local area by Wed weak upper troughing west of the region allows for increasing WSW flow aloft. A stronger upper trough over the northern Great Lakes will shift ESE through the day into the St Lawrence Valley. The low level pressure gradient will tighten in between sfc hi pres well off the coast and lo pres N of the Great Lakes. This will result in most if not all of the local area breaking into the warm sector by late Wed morning or Wed afternoon. SW winds will avg 10-15 mph and should see skies avg out partly sunny after early morning low clouds. A very low prob for late day tstms Wed (only about 20% w/ minimal lift over the region despite a return to very warm and fairly humid conditions). Highs Wed will avg in the l-m80s on the ern shore to the u80s to around 90F elsewhere. Flow aloft becomes more WNW Wed night into Thu w/ a (weak) frontal boundary approaching the local area from the NW. ISOLD-SCT tstms (mainly) Wed eve...partly cloudy Wed night w/ lows in the u60s-l70s. Enough of a NNW push aloft to bring some drier air into nrn/central areas of the FA Thu, while remaining a little more humid over far srn/SE VA and NE NC. Partly sunny S Thu and mostly sunny N with 20-30% PoPs for afternoon SHRAS and tstms mainly along-S of the VA-NC boarder. PoPs 10% or less N and central zones. Highs in the mid to upper 80s. Models continuing to show a sharpening/building of an upper ridge from the srn Plains to the Great Lakes beginning Fri while trough aloft amplifies off the E coast. The result will be hi pres building into the local area from the NNW...pushing unsettled/convective wx mainly S and SW of the FA. Lows Thu night from the u50s to l60s...except m60s at the coast in SE VA/NE NC. Mostly sunny Fri w/ the humidity remains low (dew points mainly the u50s-l60s) and highs ranging through the 80s. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 400 PM EDT Tuesday... Guidance continues to show an upper-level ridge building from the Plains to the southern Great Lakes this weekend through early next week. The result will hot, humid, but mainly dry weather for much of the extended period. Monday has the potential to be the hottest day of the year so far in spots as both the latest 12z GFS and ECMWF are forecasting 850 hPa temperatures of 20-22C in central/southern VA. There is a slight chance of a few isolated afternoon/evening t-storms (mainly over the western half of the CWA) on Sunday/Monday. Both the GFS and ECMWF have a cold front approaching the region from the north next Tuesday- Wednesday. This cold front will bring a better chance of more widespread showers/t-storms. Currently have PoPs no higher than 40% since we are still one week out. Highs in the mid to upper 80s on Saturday warming to near 90 on Sunday. Hot and humid weather expected on both Monday and Tuesday with forecast highs between 90 and 95 degrees. Expect morning lows between 67-74 from Saturday through next Tuesday. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... As of 820 PM EDT Tuesday... BKN-OVC MVFR/IFR cigs are occurring at RIC/PHF/ORF/ECG as of 00z, with BKN-OVC VFR cigs ~5kft at SBY. Sct showers continue to lift nwd over SE VA/NE NC and any showers have the potential to reduce vsby to 2-5sm. Cigs are expected to gradually fall overnight with all sites forecast to become IFR. Additionally some 2-5sm BR is possible late tonight into early Wednesday morning. A light ESE wind will become SSW by morning as a warm front lifts through the area. Cigs are expected to lift and scatter later Wednesday morning in deep layer SW flow ahead of an approaching cold front. A SW wind is expected to average 8-12kt by aftn. An isolated shower or tstm is possible Wednesday evening. The cold front is expected to drop through central and ern VA early Thursday morning, and then into ern NC by early Thursday aftn. A few showers/tstms could develop along the boundary over SE VA/NE NC midday Thursday into mid-aftn. A drier airmass and high pressure build into the region Thursday night through Saturday. High pressure moves offshore by Sunday. && .MARINE... As of 400 PM EDT Tuesday... A small craft advisory remains in effect for the northern coastal waters and entrance to the Ches Bay until 7 pm, and continue through tonight for the southern coastal waters mainly due to the short period waves of 5 to 6 ft. Onshore winds will gradually turn southeasterly tonight and diminish as the high off the New England moves offshore. Winds will then turn S-SW on Wednesday as the surface front over the Carolinas moves north of the waters. Another cold front passes through the waters Thursday morning, turning the winds N-NW, but winds do not look strong enough for Small craft conditions. Sub-SCA conditions expected through the end of the week and into the weekend as high pressure builds over the middle Atlantic. && .TIDES/COASTAL FLOODING... As of 400 PM EDT Tuesday... High rip current risk over southern waters late this afternoon into this evening with 4-6 ft nearshore waves, and a moderate rip risk over northern waters. Tidal departures across much of the area still around 1 ft above astronomical tide. With the already high astronomical tide in place, some places will see minor coastal flooding again this evening, and most likely again tomorrow evening despite the onshore wind diminishing. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Coastal Flood Advisory until 6 AM EDT Wednesday for MDZ021>023. NC...None. VA...Coastal Flood Advisory until 2 AM EDT Wednesday for VAZ099-100. Coastal Flood Advisory until 5 AM EDT Wednesday for VAZ075-077. Coastal Flood Advisory until 1 AM EDT Wednesday for VAZ084-086. MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ634- 650-652. Small Craft Advisory until 4 AM EDT Wednesday for ANZ654-656- 658. && $$ SYNOPSIS...ALB/LKB NEAR TERM...AJZ/ALB SHORT TERM...ALB/LKB LONG TERM...ERI AVIATION...AJZ MARINE...MRD TIDES/COASTAL FLOODING...AKQ
Area Forecast Discussion
National Weather Service La Crosse WI
658 PM CDT Tue Jun 12 2018 .UPDATE... Issued at 658 PM CDT Tue Jun 12 2018 Have made some slight migrations to the forecast to concentrate the severe/strong storm risk from one SLGT area into two smaller areas where the ingredients seem to suggest a bit higher storm coverage Area 1: The southern area south of about Highway 18 in NE IA and SW WI where the MLCAPE pool is around 1500 J/Kg with overlaid deeper wind shear for supercells. Area 2: The lower /relatively/ instability area further north but ahead of the deep and strong shortwave trough heading in with deep shear for supercells...near and north of I-94 in WI. Have also slowed the timing this evening to mainly be a 9pm to 12 am window. Overall the SPC Deep moisture convergence is highest where the storm initiation has recently occurred near the Twin Cities and northwest of Fort Dodge in IA. This is handled well in the recent RAP forecasts of 925mb thetaE convergence and the RAP tracks these two areas east over the next hours to bring the storms to the forecast area. HRRR runs have been targeting these two areas since I walked in at 4 pm. The area in IA may shift southeast and just brush the far southern areas south of highway 18....and may miss the WFO La Crosse northeast Iowa counties totally. Have refined hourly storm chances in the forecast as well to represent this thinking. With deep shear, severe storm chances have to be considered. CAPE will diminish slowly through the evening thus best chances for severe storms do as well. However, dynamical forcing of strong shortwave trough in northern area of storms will make up for some of the CAPE loss. && .SHORT TERM...(This evening through Wednesday) Issued at 305 PM CDT Tue Jun 12 2018 Plenty of cloud cover has remained over the area today within a fairly moist air mass ahead of a surface boundary slowly approaching from the west across Minnesota. A few showers/sprinkles have developed at times today with weak isentropic upglide. Of interest will be a vigorous shortwave aloft that will approach northern Wisconsin this evening. Stronger flow will support deep layer shear of 40-50 kts. Limiting factors include timing of the wave and instability with RAP MUCAPE ranging from 500-1000 J/kg across northern Wisconsin to near 2000 J/kg in northeast Iowa. Will have to watch cloud trends late this afternoon for any clearing. With the greatest lift with the shortwave across northern Wisconsin, expect the highest chances for storms in this area, with isolated/scattered storms possible farther south along the surface boundary where instability is higher but forcing from the upper wave is weaker. Given the forcing and shear present, could see a few strong to severe storms with a hail/wind threat, mainly this evening, before large scale subsidence takes hold as the shortwave passes to the east overnight. Wednesday will be a very nice day as precipitable water values fall to around half an inch with dry high pressure over the area. Highs will be around 80 in many areas with mostly sunny skies. .LONG TERM...(Wednesday night through Tuesday) Issued at 305 PM CDT Tue Jun 12 2018 The main concerns through the extended period will be a return to hot temps and thunderstorm chances. Even by Thursday mid/upper ridging will be beginning to build across the Midwest with temps/moisture beginning to increase. The ridge centered over the Mid Mississippi Valley will remain in place through the weekend downstream from a deepening upper trough over the western US. An upper trough passing to the north and east will help to knock the ridge down early next week and drive a front through the area. Plenty of Gulf moisture will be advected northward on the western periphery of the ridge setting up a humid/unstable pattern across the region into the Midwest through the weekend with the GFS indicating precipitable water values could exceed 1.75 inches at times. Showers/storms are possible by Thur night and Friday with increasing moisture transport/warm advection. A frontal boundary will likely be situated somewhere from the northern plains through the upper Great Lakes with occasional thunderstorm complexes riding the periphery of the ridge near the frontal zone through the weekend. Will have to watch where this boundary sets up and how far south into the more capped warm sector any of these storms can reach. Could see heavier rainfall as well as some stronger storms, though, near the frontal zone,currently favoring northern parts of Minnesota and Wisconsin. South of the front, heat will be the main concern. The 12.12Z ECMWF shows 925 mb temps of 27-30C over much of the area Fri-Sun afternoons with the GFS a few degrees cooler. In the absence of any storms that sneak south or thicker cloud cover, the higher ECMWF 925 mb temps would support highs well into the 90s. Dew points in the 60s to near 70F would result in even higher heat indices, leading to potential heat concerns. Overnight lows likely will remain near or above 70 over the weekend for much of the area. Some uncertainty remains given potential for convection and questions exactly where the boundary will be set up, but it certainly looks like a very warm/hot and humid weekend. Temps may trend downward behind a front early next week, but timing of the front is still in question. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 658 PM CDT Tue Jun 12 2018 Have removed the VCTS from the TAF sites as confidence in storms being around is falling. Overall there is some instability around the area ahead of a strong weather system heading into Minnesota. This will provide storm initiation near the Twin Cities this evening and these storms will shift east. It seems the activity may build south, but not far enough to reach the TAF sites. Plan on monitoring this closely and should conditions warrant, will need to add CB and VCTS into the TAFs again. Current thinking is a VFR CIG with storms passing well north of the airfields in the 02-05Z window making them circum-navigatable. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ UPDATE...Baumgardt SHORT TERM...JM LONG TERM...JM AVIATION...Baumgardt
Area Forecast Discussion
National Weather Service Charleston SC
1045 PM EDT Tue Jun 12 2018 .SYNOPSIS... A stationary front will meander across the area today, then lift north as a warm front by Wednesday. A trough is forecasted to prevail inland Wednesday and Thursday followed by a slow moving backdoor cold front Friday into this weekend. && .NEAR TERM /THROUGH WEDNESDAY/... As of 1041 PM: Convection over land should continue to weaken over the next hour, then coverage should decrease to isolated. Based on radar trends and latest HRRR, convection should remain scattered over the near shore areas through late tonight. I will adjust PoP timing and values. As of 915 PM: Deep convection continues across portions of SE GA and SC. However, most of the coastal counties have been worked over and stability values continue to increase. A few inland GA area remain unstable and could see showers and thunderstorms develop as the outflow advances. I will keep CHC PoPs in the forecast for the rest of this evening. Any storms that do develop will move very slowly. As of 750 PM: Convection is expected to gradually dissipate through the rest of the evening, leaving a few showers/thunderstorms over the marine areas. I will update the forecast to adjust PoPs and weather. Temperatures within the rain-cooled areas will range in the mid to upper 70s through mid evening, then should begin to gradually cool. I will update the low temperature forecast to range from the upper 60s inland SC to the low 70s along the coast. As of 610 PM: Convection over the SC Lowcountry has generally dissipated. However, convection across SE GA is likely reach a peak in coverage. I will update the forecast to adjust PoPs and Weather. Latest tide forecasts adjusted for observed anomalies show water levels just above advisory thresholds at both the downtown Charleston and Fort Pulaski gauges. Previous Discussion: Tonight: Fairly widespread convection has developed along a stalled front today. The primary focus has been in the Charleston vicinity where storms initially lined up west-east this morning. The storms have since become more north-south oriented as typical diurnal clearing has developed across the ocean behind a weak seabreeze circulation. Locally heavy rainfall has occurred, and there was even video evidence that a waterspout occurred off the coast of Isle of Palms late this morning. The second convective focus has been along the lower Savannah River along the westward extension of the front. Activity has generally been less significant here, however the collision of the seabreeze with the front led to one particularly strong storm between Savannah and Tybee Island earlier. Convection should gradually diminish in coverage this evening, perhaps shifting back out of the water as instability wanes inland. The 12z NAM along with the more recent runs of the RAP and HRRR seem to have a good handle on local winds and the current frontal position, and show a shift in the location of convection pretty clearly overnight. Some debris cloudiness should linger overnight inland, perhaps enough to keep any late night fog isolated in coverage. With a humid, tropical airmass continuing lows should only fall into the lower to middle 70s. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... The mid-levels will consist of a weak trough over the Southeast Wednesday and Thursday. Friday the trough shifts offshore as a strong ridge builds from the west. At the surface, a warm front will be north of the area Wednesday. A trough will be inland Wednesday and Thursday while high pressure remains in the Atlantic. A cold front will approach from the north Friday. Plenty of moisture will remain in place during the short term with PWATs ~2". The instability remains in place each afternoon with Wednesday and Thursday being comparable. Friday the models seem to indicate less instability despite the approaching front. Wednesday we trended POPs up, but kept them at chance Thursday and Friday. POPs will be the highest during the afternoon and along the sea breeze. We may need to increase POPs on Friday due to the approaching front. Showers/thunderstorms should remain concentrated over the coastal waters during the overnight/morning hours, migrating/developing inland during the afternoon/evening hours with the sea breeze and outflow boundaries. Locally greater coverage of showers/thunderstorms should be expected. The main threat will be heavy rainfall and locally gusty winds. Daytime temperatures will be near normal and nighttime temperatures may be a few degrees above normal. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A cold front will be just north or over the area Saturday. The front will slowly move south during the long term, possibly becoming located south of our forecast area by early next week. The weather will be highly dependent on the location of the front. The forecast is for summertime convection on Saturday. The convective potential should be much lower early next week as the front moves south. North of the front will be slightly drier conditions and maybe cooler temperatures. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... Convection is expected to gradually dissipate through the rest of the evening, leaving a few showers/thunderstorms over the marine areas. The forecast challenge will be the timing and placement of restrictive ceilings tonight. Based on forecast soundings and MOS, I will indicate MVFR ceilings at KCHS through tonight, with a period of IFR ceilings around dawn. KSAV should see MVFR ceilings develop by 8Z and remain until mid morning Wed. Deep convection should develop along a seabreeze at both terminals during the afternoon and evening, highlighted with a PROB30. Extended Aviation Outlook: Mainly VFR. Brief flight restrictions are possible in showers and/or thunderstorms, mainly each afternoon and early evening. && .MARINE... Tonight: A backdoor cold front drifted down to between Charleston and Hilton Head earlier this morning. A weak seabreeze has since made the front harder to locate but it likely still sits south of Charleston based on northerly wind direction still observed in Charleston and points north. Light winds on either side of the front should continue overnight, strengthening only to 10 knots from the SW along the GA nearshore and offshore waters late tonight. Based on buoy reports seas are likely still 2-3 feet, with no significant change anticipated through daybreak Wednesday. Showers and thunderstorms have mainly shifted inland, but may redevelop back off the coast overnight, with 30-50 percent coverage expected. Extended Marine: A warm front will be lifting north of the area Wednesday. Wednesday and Thursday the coastal waters will be sandwiched between a trough inland and Atlantic high pressure. A southward moving cold front will slowly move through the area Friday into the weekend. Expect mostly southwest winds across the waters through Friday. The exception will be during the afternoon near the coast where winds will likely become more south and increase a bit in speed in association with the sea breeze. Winds will transition this weekend with the front. Occasional thunderstorms could bring gusty/erratic winds and frequent lightning, especially during the overnight hours for the entire forecast period. && .TIDES/COASTAL FLOODING... High tides associated with this month`s New Moon should allow the evening high tides Wednesday through Friday to approach coastal flood advisory levels. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM... LONG TERM... AVIATION...NED MARINE... TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Duluth MN
643 PM CDT Tue Jun 12 2018 .SHORT TERM...(This evening through Wednesday) Issued at 332 PM CDT Tue Jun 12 2018 A slow moving cold front extending from Ontario, through the MN Arrowhead, and through northwest WI is poised to accelerate and finally move out of the Northland by later this evening. An approaching, potent shortwave trough from the west will give it the acceleration to pick up steam. Extensive cloud cover today is hanging on much longer than forecast, which is limiting the daytime heating, yet late afternoon and evening clearing may provide more heating to build up instability for thunderstorms. This approaching wave will bring moderate to strong forcing for ascent by this evening when it gets closer to the region, and the cold front will also provide some forcing. There is a good chance thunderstorms will develop by this evening in northwest WI and the MN Arrowhead, and some of the storms in WI this evening could be strong to severe. There will be 1000 to 2000 J/kg of MUCAPE and 40 to 50 knots of deep layer wind shear in northwest WI, enough to result in organized storms capable of hail and strong wind gusts. The precipitable water values will be about 1.25 inches, an environment that may lead to brief heavy rain. The limiting factors on severe weather will be that the deep layer wind shear is mainly the result of wind shear, and not direction shear, and there will be a lack of low-level wind flow to feed the storms. Have been leaning on the HRRR and RAP for timing and precipitation chances, which seem to have been doing well with the showers and weak storms we have seen today. Plus, these models have been better with the cloud cover trends, which will obviously play a big role in the destabilization of the boundary layer. There will be clearing overnight in the wake of the passing cold front and shortwave trough. High pressure will move into the region going into Wednesday. Overnight lows will be in the upper 40s and low 50s. Wednesday looks sunny and breezy with highs in the middle to upper 70s. .LONG TERM...(Wednesday night through Tuesday) Issued at 332 PM CDT Tue Jun 12 2018 Several rounds of thunderstorms, heavy rainfall, and possible flooding Friday through late Sunday night remain the primary concerns during the long term. Ridging at the surface and aloft to continue Wednesday night and Thursday over the Northland. Storms over the Dakotas Wednesday evening should slide to our south on the periphery of the surface ridge. Highs Thursday will reach the upper 60s to low 80s. A more active pattern is expected Thursday night through the weekend. A blocking pattern is forecast to set up over the Northern Pacific with the eastern anchor over the Intermountain West. The mid-level ridge will slide to the Deep South setting up ample moisture flow from both the Gulf and the Pacific into the Upper Midwest. The upper level features will slowly evolve from Thursday night through early next week as shortwave pass around the base of the low over the western states and north of the ridge over the south. A warm front will lift into the Northland Thursday afternoon and evening. Thunderstorm chances increase Thursday evening, and especially overnight, in response to surface convergence and a strengthening low-level jet. The complex of thunderstorms will migrate generally eastward Friday morning as it weakens. A cool front will move eastward across Minnesota and northwest Ontario on Friday, which will set the stage for another round of storms Friday afternoon and evening. Some of the storms may be strong to severe with 1 km mixed layer CAPE of 2 to 4 kJ/kg forecast. Deep layer shear will be lacking early in the evening, so initial storms may pulse up and down creating a damaging wind threat and a potential for large hail. The storm threat continues during the night as precipitable water values increase on a strengthening low-level jet. PWATs from the GFS of 1.7 to 2 inches are forecast overnight with robust 850 mb moisture transport focused south of US 2 in Minnesota and Wisconsin. In addition to the abundant moisture available, storm motions will be oblique to the LLJ suggesting training storms are possible. Storms moving over the same locations overnight will result in excessive rainfall and a potential for flash flooding late Friday night and Saturday morning. The baroclinic zone will become quasi-stationary over Wisconsin and Michigan, Saturday afternoon but is forecast to lift northward as a warm front over Minnesota and the Dakotas. The Pacific moisture stream will be enhanced by that time as the remnants of Hurricane Bud stream northward across the Four Corners region and into the Plains. Strong to severe storms are possible once again by late afternoon with stronger deep-layer shear and MLCAPE of 2-4 kJ/kg once again. GFS PWATs climb to between 1.8 and 2.2 inches from the Iron Range south by late afternoon. Training storms are possible Saturday night and early Sunday morning raising the risk of flash flooding once again. The front will become quasi-stationary once again from southwest Minnesota to northern Wisconsin and Upper Michigan. Strong thunderstorms are possible once again south of the boundary from central Minnesota across nearly all of northern Wisconsin. Afternoon MLCAPE values will push into the 1.5 to 3 kJ/kg range with deep layer shear of 35 to 40 knots. The severe storm threat will transition once again to heavy rainfall during the evening and overnight hours with flash flooding. Showers and storms will continue Monday morning in northwest Wisconsin and gradually taper off by afternoon. High pressure will build into the Northland once again ushering in a quieter period Monday night into Tuesday. In addition to the severe weather and flooding potential this weekend, temperatures will climb into the middle 80s for the southern half of the forecast area. Heat index values could approach 90 degrees south of US Highway 2 in Minnesota and Wisconsin. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 629 PM CDT Tue Jun 12 2018 A cold front is expected to set off some spotty showers and thunderstorms this evening, before moving off to the east. While the majority of thunderstorm activity is expected to affect areas of northwest Wisconsin, there could be a shower or thunderstorm this evening from KBRD to KHIB to KDLH for a short time. VFR conditions will be widespread, but the showers or storms could briefly reduce conditions to MVFR. Conditions will then improve behind the front, although there may be a bit of fog later in the night. Wednesday is shaping up to be a VFR day with mostly clear skies. && .PRELIMINARY POINT TEMPS/POPS... DLH 52 78 53 77 / 10 0 0 0 INL 46 78 48 81 / 10 0 0 0 BRD 51 78 54 80 / 10 0 0 10 HYR 52 78 50 79 / 40 0 0 0 ASX 53 78 52 78 / 40 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ SHORT TERM...Grochocinski LONG TERM...Huyck AVIATION...DAP
Area Forecast Discussion
National Weather Service Des Moines IA
701 PM CDT Tue Jun 12 2018 .SHORT TERM.../Tonight through Wednesday/ Issued at 319 PM CDT Tue Jun 12 2018 Decent 500mb shortwave looks to cut across Minnesota dragging a cold front through the state late tonight. The latest HRRR (and preceding runs) remains consistent with bringing a few storms into the northwest by around 00z today. Certainly plenty of MUCAPE present this afternoon into this evening and enough forcing with the fropa to be concerned with the severe storm potential this evening over northern Iowa. Shear profiles and helicity are weak, especially in the lower 3km, and thus have very low confidence with the tornado threat. With LCL heights range around 750-1000m and DCAPE around 1000 J/kg, more concerned with the elevated hail threat and damaging winds. Surface high pressure builds into the state throughout the day Wednesday providing a very pleasant and cool day across the forecast area. .LONG TERM.../Wednesday night through Tuesday/ Issued at 319 PM CDT Tue Jun 12 2018 Wednesday night into Thursday...Strong mid-level theta-e advection punches into the state late Wednesday night with the LLJ just to the west of the forecast area during this time. Greatest storm chances look to be past 06z Thursday through 18z across western to northern Iowa. The time of day looks to limit the severe threat with the lack of significant instability and deep forcing available. Friday through Tuesday...the main forecast concern was focused on the heat wave beginning Friday and lasting into early next week. Confident in three consecutive days of max temperatures well into the 90s from Friday through Sunday. There were a couple minor changes with the ongoing forecast, but significant enough that the heat index forecast was shifted higher. Both Friday and Saturday afternoons are likely to be slightly windier with models in good agreement with the deeper mixing. Friday is expected to see the stronger winds and with highs in the mid-90s and dew points in the lower 70s, it`ll feel like a blast furnace Friday afternoon. Saturday, and even Sunday, will not provide any relief. Winds appear to be weaker and the dew points look to be slightly higher with less mixing. Regardless, sultry heat index values in the triple digits are expected during the peak heating all three days Friday to Sunday. The biggest thing to monitor is the surface dew points over the weekend as the current forecast still might be a degree or two too low, especially if the mixing does not materialize. Overnight lows remain in the 70s over the weekend, providing little relief the heat and confidence is increasing a headline might be needed by Friday through Sunday. Monday into Tuesday...upper level ridge of high pressure begins to break down with a cold front anticipated to push south across the state Monday afternoon into the evening per GFS. The ECMWF remains dry Monday as it suggests the front through the state by Tuesday. Thus, there is the potential for Monday to be another hot day if the ECMWF solution holds true. && .AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/ Issued at 700 PM CDT Tue Jun 12 2018 The primary concern will be thunder trends and restrictions caused by those storms this evening with high confidence in VFR conditions through the period otherwise. Have included VCTS wording were thunder is possible over the next several hours, mainly north, with VCSH or nil wording elsewhere until confidence increases. Likely no non-VFR mention anywhere until confidence increases. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...Podrazik LONG TERM...Podrazik AVIATION...Small
Area Forecast Discussion
National Weather Service Grand Rapids MI
1026 PM EDT Tue Jun 12 2018 LATEST UPDATE... Update .SYNOPSIS... Issued at 327 PM EDT Tue Jun 12 2018 A few showers and perhaps a weak thunderstorms or two will develop this afternoon as a warm and humid airmass moves into the area. Locally heavy rainfall is possible under the most intense cells. A cold front will then sweep through the Great Lakes tonight and into Wednesday morning along which a few showers are possible. Cooler and less humid air will then settle into the area for the remainder of the week. && .UPDATE... Issued at 1025 PM EDT Tue Jun 12 2018 I have increased the pop to around 50 percent during the early morning hours of Wednesday (mostly from 3 am till 8 am). Seems there is a decent chance some of this will be isolated thunderstorms. Based on the latest data from the high resolution models and looking also at SPC SREF 3 hour thunderstorm probability from the 21z run it seems there is a better spike in the unstable cape in the 3 am till 9 am time frame as the cold front comes through. Curiously the NAM12 thunderstorm probability rises to 90 percent in that time frame. Also the HRRR and ESRL HRRR do show the convection developing near MSP and north of DSM correctly and both models develop a broken area of convection that moves through this area from North to South (entire CWA alone the lake shore) in the 4 am till 8 am time frame. The RAP model moisture transport vectors in the 4 am till 8 am time frame have increased significantly over the past few model runs with the strongest values between HOL and MKG. Still the best dynamics are north of our CWA. Even so the 850 to 700 rh, which is usually a good indication where the rain will be rises to between 80 and 85% as far south as HOL around sunrise. As for the risk of thunderstorms, the cape is narrow but extends to near 42,000 ft. The most unstable cape on RAP model reach 1,200 j/kg south of Grand Haven and west of US-131 in the 4 am through 8 am time frame. So my spin the developing line of convection will increase over the next few hours and most locations in SW Lower, west of US-131 will see some showers possibly an isolated thunderstorm in the 3 am to 8 am time frame. && .SHORT TERM...(This evening through Thursday night) Issued at 327 PM EDT Tue Jun 12 2018 While dew points continue to slowly increase across our area, abundant low-level cloud cover across the lower third of lower Michigan as well as a lack of any synoptic or mesoscale feature to aid in southerly moisture transport has really hampered destabilization this afternoon. Unsurprisingly, short-term model guidance continues to back off on precipitation potential this evening which at this point seems quite reasonable. Where skies have been somewhat clear today, meager instability is being achieved (SPC RAP analyzed 500 J/kg or so of MUCAPE) with shallow but somewhat congested cumulus streets developing along a line from roughly Traverse City southward toward Muskegon. With these considerations in mind, the expectation is (still) for a few scattered showers to develop along the Michigan/Indiana border (where somewhat better moisture resides) and along the far northern CWA with dry conditions expected elsewhere. Given very meager low- and mid-level lapse rates, I really don`t think we`ll see widespread thunder. However, with PWATS > 1 inch, showers that do develop are likely to produce moderate to heavy rainfall. Attention then turns to the potential for some quick-moving showers along a cold front expected to sweep through the area tomorrow morning. While showers and storms are expected to develop along the front in Wisconsin and the U.P. of Michigan this evening, coverage will likely decrease overnight over Lake Michigan except across the north in closer proximity to the strongest forcing. A few showers may redevelop along the front by mid-morning tomorrow though coverage is expected to be widely scattered at best. More robust development is expected east of our area in far eastern Michigan and into southern Ontario where diurnal timing will be more favorable. Of perhaps more concern is the potential for strong northwesterly winds along the backside of the cold front. Model guidance has really started to hone in on a the development of a narrow but intense low-level core of winds along the backside of a deepening low pressure system in eastern Ontario with 850 mb (925 mb) winds approaching 70 kts (50 kts) over parts of the upper Great Lakes. Based on the track of the low, the strongest winds are expected to occur over the eastern U.P. of Michigan southeastward into southern Quebec. Locally, winds may gust upwards of 30-35 mph northeast of a line from Bristol to Lansing, with 20-30 mph elsewhere across western lower Michigan. Thursday looks quiet with dry and sunny conditions expected. .LONG TERM...(Friday through Tuesday) Issued at 327 PM EDT Tue Jun 12 2018 The main challenges in the long term deal with the potential for storms and high heat over the weekend. There is some potential that warmer temperatures aloft over the CWA may limit the convective risk. For now will hold onto the potential for some storms. The pattern will support the formation of some nocturnal MCS`s over the weekend. A southerly low level jet will reach into the Upper Plains Friday night. That should set off a cluster of storms. As this system tracks through the mid level ridge in that should drop southeast with time..and into parts of the Western Great Lakes region. Will feature rather high POPs for this possible system...mainly northern zones. Similar kind of setup for Saturday night...although the low level jet will be a little further east and does veer somewhat with time. Additional showers and storms look possible. Then with Monday...the wind fields look stronger here in MI with instability around. A cold front will be pressing down from the north. Given the combination of these looks like thunderstorms could become numerous....with a few stronger storms possible. Heavy rain could also be a risk given the high PWAT values forecasted. It looks likely that some 90s will arrive over the weekend. Sunday looks to be the warmest day. If the surface front comes through later Monday...90s will be possible then as well. When you combine surface dew points closer to 70 and the potential for ambient temperatures to reach 90...apparent temperatures could make a run at 100 degrees. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 755 PM EDT Tue Jun 12 2018 We currently have MVFR cigs along I-94 TAF sites and VFR along I-96 TAF sites. There are a few isolated shallow, but heavy rain showers around the area but I do not expect them to impact any of the TAF sites before they dissipate shortly after sunset. The main issue for tonight through is the potential for dense fog and LIFR cigs/vsby after midnight till around sunrise. There currently is a large area of dense fog over Lake Michigan that can be seen in the visible satellite images and slow on coastal web cams (at 7 pm). As front cold front approaches the area this will turn winds below 1000 ft to a more southwest to westerly direction. That in turn will bring the low clouds and fog inland. I do not expect the low visibilities to reach all TAF sites but the low ceiling will. Once the front comes through (12-15z) skies should clear from west to east. There may be a few showers with the cold front but that should not change cigs or vis significantly from what it already would be. Once the front goes through skies should be and it will be breezy. Expect NW winds of 15 to 25 mph at just about all of our TAF sites during the day Tuesday. && .MARINE... Issued at 327 PM EDT Tue Jun 12 2018 Areas of dense fog may develop tonight over Lake Michigan as a moist airmass continues to move over the relatively cold water. The fog will quickly abate Wednesday morning as a cold front sweeps through the lower Great Lakes bringing drier air and increasing northwesterly winds to 15-20 kts. The highest winds will be short lived with gusts decreasing to 5-10 kts by Wednesday evening. Relatively calm conditions are then expected for the remainder of the week. && .HYDROLOGY... Issued at 327 PM EDT Tue Jun 12 2018 Scattered showers and thunderstorms today through Wednesday morning will have the potential to produce locally heavy rain. Rainfall should be brief, but may cause ponding on roads and low-lying areas, and rapids rises in small creeks and streams. No flooding of mainstem rivers (such as the Grand, Kalamazoo, Muskegon) is expected. Dry weather is expected Wednesday afternoon through Friday. A more active pattern then looks to set up over the Great Lakes region Saturday through Monday. This could lead to multiple rounds of heavy rain affecting the same location, and will need to be monitored. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...Dense Fog Advisory until 8 AM EDT Wednesday for LMZ844>849. Small Craft Advisory from 10 AM to 4 PM EDT Wednesday for LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...Borchardt SHORT TERM...Borchardt LONG TERM...MJS AVIATION...WDM HYDROLOGY...HLO MARINE...Borchardt
Area Forecast Discussion
National Weather Service Nashville TN
739 PM CDT Tue Jun 12 2018 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Hrrr appears to be somewhat useful this evening, for a change. Convective complex is spreading slowly southeastward but weakening as the better divergence fields weaken. Momentum, however, looks strong enough to allow for the expansion of likely trw- further south and east. Furthermore, complex will continue to dive into higher capes as it moves southeast. Update out shortly. && .AVIATION... 00Z TAF DISCUSSION. VFR expected unless otherwise noted. Consensus short term model solutions, including latest HRRR showing area of convective activity presently entering NW portions of mid state, should shift SEWD with time but weaken. Believe main impact at CKV should be no later than 13/01Z CKV, around 13/03Z BNA, and around 13/05Z CSV. Will address within TEMPO groups MVFR ceilings/vsbys at CKV/BNA as stronger shwr/tstms moves over terminals during a two hour time period window. Convection chances should decrease as evening hrs progress, but can still not rule out iso shwrs at least in VCNTY. As upper level troughing becomes more pronounced with embedded shortwave passages also, along with sfc front approaching mid state and possibly moving into NW portions of mid state by 13/24Z, the stage is set for sct to numerous shwrs/tstms development after 13/15Z. Orographic diurnal influences should enhance potential of numerous shwrs/tstms Cumberland Plateau Region/CSV. Will go with FM group mention of VFR shwrs/tstms CSV 13/17Z. However, with considerable uncertainties still due to predominate nature of pulse type convection elsewhere, will mention VCTS only. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......21 AVIATION........31
Area Forecast Discussion
National Weather Service Shreveport LA
1001 PM CDT Tue Jun 12 2018 .UPDATE... Made some changes to sky only at this time. && .SHORT TERM... Temperatures are in the upper 70s and low to mid 80s and doing fairly well on the hourly gridded data. Winds are light SE at most locales or even calm. The radar has quieted down early this evening and as such a lot of the debris cirrus has thinned early as well. Some of the mostly cloudy wording in some zone groups will become partly cloudy. KSHV 88D is currently showing a few tiny shower cells in Rusk and Panola counties with the recent thunder in Bowie already gone. The only storm left is on the MS river near Greenville and shows up fairly well on the HRRR along with a blip near three states. The HRRR dries out all of the very limited QPF in the next hour anyway. We will rerun the zones to include new sky and the 03Z pop grid so as to remove early evening wording. No other changes needed at this time. /24/ && .PREV DISCUSSION... /issued 656 PM CDT Tue Jun 12 2018/ AVIATION... For the ArkLaTex, we are done early today with a quiet night ahead. Light S/SW wind with MVFR cigs/vsby 13/10-16Z becoming VFR with models hinting at more VCTS type activity from KTXK to KELD and KMLU by late morning and early aftn. Otherwise our winds resume S/SW 5-10KT with expected amendments and tempo groups as radar start to light up with scattered TSTMS. Attm our climb winds are SW10-15KT veering to NW flow aloft. Outlook is similar with p.m. TS at varied terminals for the remainder of the work week. /24/ PREV DISCUSSION... /issued 338 PM CDT Tue Jun 12 2018/ SHORT TERM... Persistant upper-level weakness across the region continues to generate scattered afternoon and evening showers and thunderstorms areawide. Convection to diminish around sunset with overnight low temperatures forecast to fall into the low to mid 70s. Upper-level ridge to strengthen on Wednesday with temperatures forecast to climb into the low to mid 90s across much of the region. However, enough instability should exist across southern Arkansas and northeast Louisiana from remnant weakness to again support scattered showers and thunderstorms across these areas with high temperatures forecast to climb into the lower 90s. Otherwise, low-level moisture trapped beneath diurnal inversion could generate widespread stratocu ceilings around daybreak each morning. /05/ LONG TERM.../Thursday through Tuesday/ On Thursday, the upper ridge, which has dominated our weather for the last week, will continue to slowly migrate northeast into North Texas and Oklahoma, while also expanding eastward slightly. The increased subsidence in the center of the ridge should help to keep any chances for convection confined to areas of a line from DeQueen AR to Lufkin TX. With the center of the ridge moving north of the area on Friday, this will allow mid-level moisture from the Gulf of Mexico to stream northward into the region as deep southerly flow returns. This should help to increase the coverage of diurnal convection Friday, especially across Louisiana and Southern Arkansas. For Saturday and beyond, a mid-level trough will move into the northwest Gulf of Mexico on the southern periphery of the upper ridge. As the ridge moves eastward towards the Ohio River Valley, this should steer the trough northward through Central Texas and towards the Southern Plains. This will result in a gradual increase in convection across the entire area beginning on Saturday. Convection will likely be widespread Sunday and Monday before becoming more confined to the northwest half of the area on Tuesday. Best rain chances and greatest coverage of showers and thunderstorms will continue to be during peak daytime heating, but scattered convection should persist into the overnight hours. There is still considerable uncertainty in the forecast after Friday, so potential rainfall amounts are difficult to determine. However, medium range models have been fairly consistent over the last couple of days advertising these rain chances. Despite the uncertainty surrounding the rainfall, the associated increase in cloud cover combined with the rain should bring daytime high temperatures below 90 degrees F for the beginning of the next work week. CN && .PRELIMINARY POINT TEMPS/POPS... SHV 76 94 74 94 / 40 10 10 20 MLU 75 90 73 92 / 40 30 20 30 DEQ 72 92 71 94 / 30 30 10 10 TXK 75 91 74 94 / 30 20 10 10 ELD 74 88 72 93 / 40 40 20 20 TYR 75 93 73 94 / 20 10 10 10 GGG 75 94 73 94 / 30 10 10 10 LFK 74 95 72 93 / 20 20 10 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 24/05/09