Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/27/18

Area Forecast Discussion
National Weather Service Bismarck ND
1024 PM CDT Sat May 26 2018 .UPDATE... Issued at 1021 PM CDT Sat May 26 2018 POPs were again scaled back a bit as there has been little development east of the main convection across eastern Montana thus far. High res models though continue to advertise development into western ND 03-05Z. Severe Thunderstorm Watch 122 continues. UPDATE Issued at 836 PM CDT Sat May 26 2018 Thunderstorm activity remains over eastern Montana, and appears to be 1-2 hours yet before far western ND will see any of this activity based on latest high res model output. Thus delayed bringing convection across the MT/ND border until closer to 03-04Z. Latest HRRR and other high res models also continue to develop convection across northern SD and into my south central and perhaps my southeast after 05Z, as the low level jet develops from the central high plains north-northeast across western/central SD into my the southern half of ND. UPDATE Issued at 704 PM CDT Sat May 26 2018 SPC went with a severe t-storm watch for most of western North Dakota now through early Sunday morning. Drier air across northwestern ND kept the watch south of the Missouri River, which high res CAMs support. The question is then what materializes later this evening as the area of storms move into central ND. There is some potential for an MCS/linear line developing and turning southeast, impacting south central ND later this evening and overnight as a strong low level jet develops across the central Dakotas. A possible eastward expansion of the watch is thus possible and will be monitored over the next several hours. && .SHORT TERM...(This evening through Sunday) Issued at 214 PM CDT Sat May 26 2018 Main highlight is the transition from dry conditions this afternoon to an increasing threat for showers/thunderstorms overnight. Severe weather with large hail and damaging winds remains possible favoring western North Dakota tonight. Mid/upper level ridge will shift from western ND this afternoon into eastern ND by 12z Sunday. Per water vapor loop, an upper level low circulating over north central Nevada will slowly translate north and east and into North Dakota Tuesday/Tuesday night. Several shortwaves will eject out from this main low until early next week. A couple shortwaves tonight traversing from south central Montana into western North Dakota will result in the development of showers/thunderstorms. CAM`s show discrete cells developing in eastern Montana this evening (00z-03z), from Miles City to Glasgow, gradually morphing into a larger area after 03z. There appears to be a broken line of thunderstorms embedded within the main area that will enter western ND between 03z-06z Sunday. SPC continues with a slight risk for severe thunderstorms with large hail and damaging winds, especially western North Dakota. Further expansion and strength of the convection after midnight will be tied to the low level jet and moisture advection into central ND. For most of tonight, cloud bases will remain high across central ND, closer to the ridge axis; while lowering across the far west closest to the highest instability and approaching shortwaves and associated showers and thunderstorms mentioned above. Thus wind and hail are the primary threats. There will be a window of opportunity between 06z-12z Sunday that with an increasing low level southerly jet, moisture advection and elevated instability will lead to additional development of showers and thunderstorms for central ND late tonight through sunrise Sunday. Lingering convection early morning Sunday should wane in coverage during the day. then ramp back up Sunday evening/Sunday night, with the approach of the next mid level low. .LONG TERM...(Sunday night through Saturday) Issued at 214 PM CDT Sat May 26 2018 Periods of showers and thunderstorms, some severe per SPC remain in the forecast Sunday night through Monday night. A deeper southerly flow/moisture ensues as the main upper low from Nevada approaches. Instability and shear remain in place for severe weather especially central and southern North Dakota. A brief break in the showers/thunderstorms Wednesday as the upper low departs. Then southwesterly flow initiates again for more chances of showers/thunderstorms Friday and Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 704 PM CDT Sat May 26 2018 An area of showers and thunderstorms will shift from eastern Montana this evening and into western North Dakota between 02z-05z this evening. KISN and KDIK have the highest chance and confidence for showers/thunderstorms. KMOT and KBIS will then see chances overnight, after 06Z. Would anticipate some chances for severe weather this evening from 02-05Z for KDIK and KISN. Cloud bases will initially be high as showers/storms develop (9kft to 10kft), then lower with time towards 12z, but still remaining VFR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...KS LONG TERM...KS AVIATION...NH
Area Forecast Discussion
National Weather Service Brownsville TX
643 PM CDT Sat May 26 2018 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...VFR expected to predominate at the RGV terminals for the next 24 hours. High-pressure ridging upstream will continue to shift closer, further drying out the atmospheric column. RAP BUFKIT soundings suggest that an MVFR-level cloud deck will form tonight, but other guidance leaning away from it. Will retain FEW- SCT 015 in TAF`s but not go with a prevailing CIG due to lower confidence. Winds will generally be light SE-S, becoming more ESE Sunday afternoon as the sea-breeze front progresses inland. && .PREV DISCUSSION... /issued 321 PM CDT Sat May 26 2018/ ..The HEAT of the moment... SHORT TERM (Tonight through Sunday Night): Upstream ridging aloft remains in place over west Texas and will shift slowly east toward central Texas through the next day or two, further solidifying local stability. A deep upper low will hover over the Southwest United States during the short term, while in the GOMEX Subtropical Storm Alberto moves north from the Yucatan Channel and across the Gulf toward the north central to northeast Gulf coast during the next two to three days. Across the west Gulf and the CWA, high pressure will remain in control at the surface, with light to moderate southeast to south winds and mostly clear skies. Temperatures will continue to be above normal, particularly during the day, and the forecast will feature high temperatures a couple of degrees above guidance. The forecast values will dance around record numbers, with the 98 degs forecast at Brownsville, the 100 degs forecast at Harlingen, and the 103 degs forecast at McAllen for Sunday comparing to 99, 100 and 107 degree records, respectively. These values will combine with ambient humidity to produce mid afternoon heat index values of 103 to 108 degrees. LONG TERM (Monday through Saturday): The heat that is already in place builds further through the week, peaking on Wednesday and Thursday as position and strength of the early onset of the 500 mb "La Canicula" ridge centered from Coahuila through the Texas Big Bend combines with lower surface pressures over west Texas...forced a little bit by a slow moving 500 mb trough easing across the intermountain west and into the U.S. Four Corners region by early Friday. In my 10+ years tracking such overview parameters as 1000- 500 mb thickness and raw 850 mb temperatures, never have I seen a 587+ decameter value over McAllen and nearly 590 decameter (590!) over the Rio Grande Plains (GFS). The ECMWF is just a hair behind, and 850 mb temperatures *on the Rio Grande Plains* approach 28 or 29C (Wednesday). Combine this with deep dry air, near solstice sun angle, and rapidly drying top soils and super-adiabatic possibilities and it would not surprise to see 110+ for some areas in southern Starr/Zapata Wednesday, perhaps beginning Tuesday and continuing Thursday and perhaps beyond. The ridge shifts slowly northward by next Friday/Saturday which raises surface pressures a bit over west Texas and thereby slightly lowers the 1000-500 mb thickness and 850 temperature, but not appreciably enough to put a dent into this impressive late May and early June heat wave. So, what does this all mean? First, given the parameters above, have raised temperatures in all areas 2 to 5 degrees over previous forecast, with 104 to 107 along and west of US 281 Tuesday through Friday, only slightly lower on Memorial Day and next Saturday. The good news (if you can call it that) is abundant dry air above the few cumulus bases will mix down given expected mixing heights at or above 8000 feet, so afternoon humidity in the 20s to lower 30s will keep "feels like" temperatures close to the actual temperatures, with perhaps an exception late next week/weekend across the more populated RGV where near 110 apparent temperatures may start to appear. The aforementioned lowering surface pressures over west Texas will help enhance the afternoon sea breeze, which will gradually progress from near the coast into the mid/upper Valley by late afternoon and bring slight cooling after the highs are reached. Until then, however, 10 mph or lower winds will keep ventilation low. Bottom line? A pretty remarkable, searing heat wave more similar to July 2009 and 2015-2017 than the end of May and start of June. One final but important item: The impact of Alberto on Lower Texas shoreline. This afternoon`s "jump" reformation of the center and latest model trends suggest a far eastern Gulf of Mexico track in the short term, before some "curling" into the upper low that captures the system on Memorial Day. With the most strengthening expected after the center passes our latitude, and landfall somewhere closer to the western Florida panhandle than Louisiana, swell impacts may be a bit more limited. While there should be some tidal run up peaking at high tide Monday morning, it may only be half to two thirds to the dune line at narrow beaches, more a curiosity than anything else. Rip currents, however, which are already at moderate levels may amp up a tad and due to the huge crowds on a hot Memorial Day weekend a Rip Current Statement may be needed this evening which could extend into Memorial Day. MARINE (Tonight through Sunday Night)...Light to moderate southeast to south winds and low to moderate seas will continue along the lower Texas coast due to a persistent weak local pressure gradient over the northwest Gulf. Subtropical Storm Alberto will move north from the Yucatan Channel toward the north central to northeast Gulf coast over the next couple of days, posing no threat to the lower Texas coast. (Monday through Thursday Night)...Based on the eastward nudging of the new center for Alberto, landfall Monday will likely be a bit farther east as well (and sooner) hence there may not be ample time for significant swell to generate seas any higher than 4 feet. Blended close to TAFB in the offshore waters on Monday before whatever enhancements come from Alberto recede. Thereafter, gradient picks up a bit by Tuesday and especially Wednesday and Thursday, but mainly the typical diurnal marine layer arguments for the Gulf. Could edge near Caution (15 to 20 knot) territory Tuesday night through Thursday night bur for now kept just below. Laguna Madre may well see caution afternoons with the gradient enhanced by the sea breeze Tuesday through Thursday. Otherwise, moderate seas over the Gulf with some increase in wind waves, perhaps to 3 feet, are expected especially Wednesday night on. CLIMATE...Been flirting with records in recent days and the expected heat of the atmosphere upcoming will challenge more. The following are records for McAllen/Miller and Brownsville May 28 through 31: McAllen/Miller May 27 107 in 1973 May 28 101 in 2017 May 29 102 in 1975 May 30 103 in 2004 May 31 106 in 1967 Brownsville May 27 99 in 1973 May 28 98 in 1919 May 29 98 in 1922 May 30 100 in 1919 May 31 100 in 2005 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 53-Schroeder/65
Area Forecast Discussion
National Weather Service Charleston SC
1023 PM EDT Sat May 26 2018 .SYNOPSIS... Deep tropical moisture on the east side of Tropical Cyclone Alberto will spread into the region on Sunday. This moist airmass will linger across the area into the middle of next week, resulting in unsettled weather. && .NEAR TERM /THROUGH SUNDAY/... As of 1020 PM: I will issue a quick update to adjust sky and temperatures to observations. As of 920 PM: KCLX only detected isolated showers across the coastal areas this evening. However, the showers have generally tracked inland and dissipated. I will keep the forecast free of mentionable PoPs. 18Z run of the GFS and SREF, suggests that the potential for heavy rainfall late Sunday into early Monday is increasing. Overall there has been a eastward shift in the track of Tropical Cyclone Alberto. Southeast GA/SC will be positioned between the closed mid level over the Gulf of Mexico and a ridge across NC. Late Sunday night, the core of the H25 jet pushes south across the Mid Atlantic states. At the sfc, a trough is expected to rotate northward on the east side of Alberto, reaching the GA/SC coast late Sunday evening. The placement of the mid level heights, jet, and the sfc trough will favor the development of a Predecessor Rainfall Event (PRE). GFS and ECMWF indicate that a wide band of heavy showers, possibly embedded thunderstorms, will develop offshore Sunday evening, moving across the CWA Sunday night into early Monday morning. SREF normalized anomaly is interesting as it shows a 3 sigma signal in PW passing over the CWA between 6Z to 12Z Monday. It is possible that the heavy rainfall could overlap with the high tide at 8 PM Sunday and 8 AM Monday. As of 740 PM: KCLX indicated little to no coverage of showers across the forecast area. I will update the forecast to remove mention of thunderstorms and lower PoPs below mentionable values over the next hour. As of 6 PM: Visible satellite indicates that earlier cool pools have drifted inland. In the wake, shallow Cu has developed over the CWA, only a few showers over Jenkins and Screven Counties. HRRR indicates that little to no coverage will redevelop through the rest of this evening and during the overnight hours. I will update the forecast to decrease PoPs, reduce thunder mention to isolated, and indicate on light intensity. Previous Discussion: Until Sunset: Showers and isolated thunderstorms continue to move inland with the sea breeze, decreasing in both intensity and coverage. This is because SPC mesoscale analysis now indicates MLCAPEs ~1,000 J/kg inland. We adjusted POPs down slightly for the next few hours to account for this. But it`s possible POPs may remain a little too high for a little too long inland. Also, attempted to again adjust the hourly temperatures to better reflect the current observations and the progression of the showers with the sea breeze inland. Tonight: Models are fairly consistent showing a period of dry weather this evening into most of the overnight. Models even hint at some stratus or fog well inland. But confidence was not high enough to include this in the forecast. Deep tropical moisture associated with an approaching Alberto will move in from the south late tonight. PWATs are forecasted to exceed 2", which is 2 standard deviations above normal for this time of year per NAEFS. We have POPs increasing from south to north late, especially around daybreak. Lows will be mild due to mostly cloudy skies, ranging from the upper 60s to lower 70s. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... Sunday through Monday: There is no change with this forecast package to the overall setup for this time period. Deep tropical moisture, with precipitable water values in the 2.25-2.50 inch range, will spread northward into the forecast area through the day on Sunday around the broader circulation of Tropical Cyclone Alberto. Rain chances will steadily increase Sunday into Sunday night, and chances are currently in the 80-90 percent range. Upper jet dynamics will provide larger scale forcing in the presence of the tropical moisture feed, and widespread moderate to occasionally heavy rain is expected just about everywhere. The main tweak to the forecast is to account for slightly faster timing, based on model consensus and the National Hurricane Center forecast track for Alberto. Rainfall amounts are expected to range 1-3 inches through Monday, with the highest amounts progged for the Charleston Tri-County region. The threat for localized flooding issues remains, with the heaviest period of rain occurring Sunday evening through early Monday morning. Tuesday: Alberto is forecast to pass well west of the forecast area on Tuesday. A very moist airmass will remain in place, and numerous to widespread showers and thunderstorms are expected to develop. This activity will be more diurnally driven, beginning quickly in the morning with the onset of heating. The overall severe threat will remain low through the short term period. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Active weather will persist through the middle-to-end of the week as deep tropical moisture remains in place. The lack of any larger scale forcing will result in a primarily diurnal trend for the POP forecast, with chance-to-likely most days and low-end-to-slight chance overnight. The flooding threat will decrease, though local issues cannot be ruled out given the ample moisture available to storms mainly Wednesday and Thursday afternoons. High pressure centered near the Bahamas will slowly assume control of the local pattern as we head into next weekend, bringing more settled conditions. Temps will trend from near to marginally above normal through the period. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Prior to the 0Z TAFs, KCLX indicated little to no coverage of showers across the forecast area. The terminals remained dry through this afternoon. Conditions across the KCHS and KSAV are forecast to remain VFR through tonight. After sunrise Sunday, sfc ridge will lift north as a trough ripples north across GA. A large broken band of showers and isolated thunderstorms is expected to develop within the trough. MVFR ceilings and periods of MVFR visibilities will likely occur with the moderate showers. I time MVFR conditions to arrive at KSAV at 14Z and KCHS at 16Z. Extended Aviation Outlook: Occasional to frequent ceiling and/or visibility restrictions can be expected at the terminals Sunday evening through Monday morning as an area of moderate to heavy rainfall crosses the area. VFR conditions will prevail thereafter, though continued unsettled conditions mean that brief periods of flight restrictions in showers and thunderstorms are possible mainly in the afternoons. && .MARINE... Tonight: Offshore buoys and stations along the coast continue to report winds of 10-15 kt associated with the inland moving sea breeze and a slightly enhanced pressure gradient. Winds should remain this intensity overnight. Seas will range from 2-4 ft, highest beyond 20 NM offshore. Sunday through Thursday: Winds will start out easterly or southeasterly on Sunday, but will gradually become more southerly into Monday as Alberto moves closer to the Gulf Coast. Southerly flow will then prevail into mid week. Speeds will generally top out in the 15-20 knot range at their strongest, staying mainly in the 10- 15 knot range. The main concern will be seas which will increase Sunday and Sunday night. For the outer waters beyond 20 nm, 6 foot seas are expected by the afternoon and could even get inside of 20 nm. A Small Craft Advisory will likely be needed for at least the outer waters Sunday afternoon into Monday. Seas will return to the 2 to 4 foot range with moderate southwest winds mid-week as high pressure near the Bahamas takes control. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM... LONG TERM...CEB AVIATION...NED MARINE...
Area Forecast Discussion
National Weather Service Grand Forks ND
1026 PM CDT Sat May 26 2018 .UPDATE... Issued at 1026 PM CDT Sat May 26 2018 Regarding thunderstorm potential tonight: Thunderstorm activity over Eastern Montana is shown to spread eastward, with a general agreement in CAMs of arrival in our far western CWA after 7Z, and the Red River Valley around 12Z. This may be optimistic on timing based on current regional radar trends. Evolution and intensity are still uncertain, and there is not a lot of agreement on that side of things at this point. RAP shows MU CAPE potentially in the 1500-2000 J/KG range in our far west by 12Z as warm front moves northward and southerly flow begins to develop, while values remain lower to northeast. At the very least keeping thunder in the forecast and adjusting timing of PoPs seemed reasonable. Any thunderstorms would become elevated and if low levels remain decoupled it will be hard to anticipate potential for any severe wind. Also, if activity outpaces increase in instability stronger updrafts necessary for larger hail may not be supported. Potential is there and this should be monitored, but overall confidence in impacts is low. UPDATE Issued at 645 PM CDT Sat May 26 2018 Only minor adjustments to near term trends, otherwise monitoring upstream activity for possible adjustments to PoP/Wx for later tonight/tomorrow. Elevated instability (MU CAPE 500-1500 J/KG) should be in place so while PoPs weren`t adjusted, I added thunder mention to late night/Sun morning grids. && .SHORT TERM...(This evening through Sunday) Issued at 246 PM CDT Sat May 26 2018 Mostly sunny skies are expected through the remainder of the day across much of the forecast area. The only exception will be across north and northwest Minnesota where a persistent cumulus field has developed in a less stable airmass influenced by a weak upper level shortwave north of the Great Lakes region. Slight instability of 500-1000 J/kg MUCAPE in this region may allow for an isolated thunderstorm or two in this region later this evening. Otherwise, a few clouds and breezy conditions will persist across eastern ND/western MN. Winds are expected to gradually diminish through the evening and overnight hours as surface high pressure shifts to the east. Rain chances will increase across eastern ND early Sunday morning as precipitation associated with a subtle mid level wave propagate into the region around an upper level ridge axis. This early morning precipitation is expected to move out of the region and make way for a second round of showers/thunderstorms Sunday afternoon. A deepening surface low across central SD will cause a northward flux of higher theta-E air into the southeast ND/west MN region. Deterministic and short- range ensemble guidance suggest a boundary layer airmass characterized by dewpoints in the upper 50s/low 60s will support moderate instability of 1.5-2.5 kJ/kg MLCAPE by the afternoon and evening hours. 0-6 km Bulk Shear values of 30-40 knots will support organized convection that will pose a threat for severe hail up to one inch and strong wind gusts up to 60 mph. While convection will likely be focused a surface warm front across the southern River Valley, uncertainty remains as to the degree of destabilization from daytime heating due to early morning showers/cloud cover and whether forcing along the front will be sufficient to initiate convection. As such, trends in surface dewpoints and cloud cover will have to be monitored to assess the afternoon severe potential. .LONG TERM...(Sunday night through Saturday) Issued at 246 PM CDT Sat May 26 2018 Temperatures... Hot weather continues Monday for the Memorial Day Holiday. Cooler temperatures begin to move in Monday with 70s and the low 80s in the Devils Lake Basin and along the international border. Cooler weather moves across of the rest of eastern North Dakota and northwest Minnesota Tuesday with temperatures still above normal but not like the recent record setting temperatures. By late next week temperatures could even to fall to close to normal as a cooler air mass moves in. Thunderstorm Potential... Thunderstorms and showers on Monday with potential for strong to severe storms. This will depend on what happens Sunday as any significant convection on Sunday will reduce the chance for strong to severe storms Monday. Bulk shear values on Monday across eastern North Dakota and northwest Minnesota in the NAM are in the 30 to 55 kt range which would support strong to severe storms. What is more in question is the instability, especially after potential Sunday convection. MU CAPE varies significantly from near 0 up to 3500 J/kg, but in the areas with the better shear values go up to closer to 2300 J/kg in the NAM and GFS. Thunderstorms will again be possible Tuesday and Wednesday but it is too early to say much about thunderstorm strength for those days. Excessive Rainfall Potential... Monday into Wednesday high precipitable water values in the NAM and GFS are above the 90th percentile for nearby sounding climatologies (BIS, ABR, and INL). This is supported by the previous upper low becoming dislodged and the trough moving towards the Northern Plains. Dryer weather expected Thursday before another chance for rain Friday into the next weekend as an upper level trough moves into the region. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 645 PM CDT Sat May 26 2018 VFR conditions should prevail through the TAF period, and gusty northwest winds should decrease early in the TAF period. Southeast winds increase during the day Sunday and a few gusts to 20kt can`t be ruled out. Primary aviation concern will be potential for showers/thunderstorms late tonight (after 08Z) through the morning, and again in the late afternoon/evening. Confidence wasn`t high enough to introduce more than VCSH at KDVL for now, but will need to monitor trends as activity develops in eastern Montana and western ND as this would be what may impact eastern ND and northwest MN later tonight. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...DJR SHORT TERM...AM LONG TERM...NC AVIATION...DJR
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
922 PM EDT Sat May 26 2018 .SYNOPSIS... A cold front will move south of the forecast area tonight. Cool high pressure will build in from the northeast on Sunday and will hold over the region into Monday with plenty of clouds expected. High pressure will shift east late Monday and Monday night as a weak warm front approaches from the west. A cold front will drop south through the region by Tuesday morning. 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 the weekend. && .NEAR TERM /THROUGH SUNDAY/... 925 PM Update... Minor changes to the forecast based on trends in the forecast database. 825 Update...So minor changes to the forecast to indicate that showers will occur and may impact your way home. Rain will occur but wont be a nuisance. 720 PM Update...Minor changes at this time. Convection is struggling over southern NH and SW Maine. Some pockets of better instability have helped better cells for a few scans...but overall these have weakened with time. Will continue to monitor. Previous discussion...Slow moving backdoor front continues to shift southwest early this afternoon with most of the associated shower activity still running from northern New Hampshire through southwest Maine. To the south...filtered sun through high clouds has boosted temps in the mid to upper 80s across southern New Hampshire. This will be the area of concern through early evening as the front continues to shift south into this unstable air mass. SPC has upgraded this area to a marginal risk for severe and radar showing convection beginning to fire over eastern New York and central Vermont. HRRR showing this activity becoming more organized as it moves into southern New Hampshire later this afternoon and evening. SPC meso analysis page showing CAPES edging into the 500 to 1000 range with moderate shear. Have included heavy rain and gusty winds in the zones for these areas but will hold off on enhanced wording to see how the situation develops. In any case...HRRR showing this activity pushing south of the forecast area around 00Z with just light scattered showers in its wake. Onshore flow sets up behind the front by late this evening and expect ocean stratus to overspread much of southern New Hampshire and extreme southwest Maine by midnight or shortly after. Lows overnight will range through the 40s in northeast zones and lower to mid 50s in the southwest. && .SHORT TERM /SUNDAY NIGHT/... High pressure will build in from the northeast on Sunday increasing moist onshore gradient and keeping much of southern New Hampshire and southwest Maine socked in with stratus. Farther to the north and east looking for filtered sun through high clouds. Looking for highs in the north and east to top out in the lower to mid 60s. Coastal and southwest zones will only see highs in the 50s. High pressure will shift off to the east Sunday night allowing low level moisture to overspread much of the forecast area overnight. Looking for areas of fog and drizzle in southern zones with the remainder of the forecast area remaining dry. Lows will generally range through the 40s. && .LONG TERM /MONDAY THROUGH SATURDAY/... High pres centered over the maritimes will continue to provide a cool, moist onshore flow into Mon, especially on the coast. Far interior locations such as southwestern NH will see warming conditions as the cool low level air mass begins to depart. A cold front will cross the region Monday night into early Tuesday with the chance of showers, mainly across northern and central zones. High pressure then builds in later Tuesday through Thursday with warming temperatures expected. Not out of the question that a few locations hit 90 on Thursday. Thereafter, some beneficial rainfall is possible Friday into the weekend if the remnants of Alberto do indeed make their way to the northeastern states as several deterministic models are showing. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... Short Term...VFR with areas of MVFR/IFR ceilings developing in southern New Hampshire and southwest Maine. This cloud cover with persist through Sunday. IFR/LIFR ceilings overspread most of the forecast area Sunday night. Long Term...VFR to IFR conditions are likely on Monday, mainly on the coastal plain where cool, moist onshore flow will persist. Improving conditions are expected Tuesday morning through Thursday where are return to VFR is expected. && .MARINE... Short Term...Have issued SCA`s for late tonight through midday Sunday as easterly gradient tightens over the Gulf of Maine later tonight. Long Term...SCA due to seas over the outer waters possible Monday, but at this time it looks marginal. && .FIRE WEATHER... Wind switches onshore this evening and overnight and remains that way into Monday, so expect high RH through Monday, with scattered showers and relatively light winds. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until noon EDT Sunday for ANZ150-152-154. && $$ NEAR TERM...Hanes/Watson SHORT TERM...Ekster/Sinsabaugh LONG TERM...Ekster
Area Forecast Discussion
National Weather Service Huntsville AL
701 PM CDT Sat May 26 2018 .NEAR TERM...(Tonight) Issued at 701 PM CDT Sat May 26 2018 Convection continues to make its final hurrah across the TN Valley this evening, with just a few showers/storms of note on KHTX. The trend will likely continue for the next hour or so, with only a rogue shower/storm expected overnight. Unlike last night where we had widespread rain and lingering stratus during the overnight/morning hours, with convection being more sparse today, fog formation is likely by sunrise. The fog will be more dense in locations that received heavy rainfall this afternoon/evening, but have included the chance for at least patchy fog area-wide in the grids. Will monitor obs through midnight and will make updates as warranted to more dense-wording in the official forecast (if need be). Several changes were necessary for the update this evening as a result of this thinking, with PoPs decreased and Sky grids updated as well. The HRRR was doing a fairly good job with the coverage of isolated/scattered convection at the moment, and so those Sky grids were implemented for the rest of the evening/overnight hours. With more clearing noted in the grids than before, this better supports the thinking for fog formation (as opposed to 80-100% coverage from before). Temps are on track to bottom out in the upper 60s to around 70F again for Sunday morning. .SHORT TERM...(Sunday through Monday night) Issued at 159 PM CDT Sat May 26 2018 A narrow mid to upper level ridge position builds into place north of Alberto as the upper trough remains over the lower OH and MS valleys on Sunday. The ridge gives way quickly during the afternoon as the first of several spokes of vorticity rotate north and northwest into the TN valley. By late in the day, expect numerous showers and thunderstorms along this feature that will translate northwest and west during the evening. A narrow dry gap behind this band is quickly filled in by a potentially heavy band of showers and thunderstorms late Sunday night into early Monday. Have carried the highest PoP in our southeast (Likely), with chance further north. The models have shown a sharp gradient to this particular rain band in successive runs, making the PoP forecast challenging. It`s possible that our TN counties may see very little from this band, while north AL gets a period of heavy rain Monday morning. Then, this abruptly diminishes and/or dissipates during day as a strong dry slot becomes ingested north-northwestward into the circulation. On Monday Night, depending on the track of Alberto either into southwest AL or southeast MS, a compact precipitation area around the circulation may affect parts of our area as early as late Monday night. The best chance may be our southwest counties based on the 12Z guidance. .LONG TERM...(Tuesday through Friday) Issued at 159 PM CDT Sat May 26 2018 As one would expect, some model discrepancies are noted with the track of Alberto (or the remnants of Alberto) after it makes landfall. The operational GFS/Euro track the system across the heart of Alabama Tuesday and to near western Kentucky by early Wednesday. The NAM is a bit faster and has more of a westward track, and is supported by a large number of GEFS members. The official NHC track is a blend of the two camps and that seems quite reasonable. For now, that would place the highest potential QPF across western Alabama Tuesday underneath the core/proximity of the lower. Depending on the track as well some areas may be in the favorable right front quadrant for rotating convective bands early Tuesday. Despite the low lifting north of the Tennessee Valley by Wednesday, expect scattered to numerous storms again especially in the afternoon with broad troughiness and high PWATs in place. Not much notable change on Thursday, and in fact we may see another uptick in precipitation with the passage of an upper s/w trough during the afternoon/evening hours. In general, have trended toward the lower end of the diurnal ranges (warmer mins/lower maxes) given the tropical airmass and likely early cumulus/convective initiation. The upper flow becomes a bit more northwesterly by late in the work week/toward next weekend as the upper ridge begins to build into the Plains. The high amplitude nature of the ridge will bring potentially extreme heat to the southern/central plains late next. Closer to home, will continue chance pops for Friday/Saturday as there`s some indications of another piece of northern stream energy working its way across the Tennessee Valley during that time frame. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 630 PM CDT Sat May 26 2018 Current convection ongoing across the region continues to dissipate as of the 00Z TAF issuance, and only an isolated shower/storm is expected overnight. With that said, mention of VCSH/VCTS was removed thru 27/01Z. Fog formation is likely overnight (compared to more stratus coverage last night/this morning), so have retained the IFR conds possible between 27/10-14Z at both KHSV and KMSL. Fog will dissipate shortly after 14Z with VFR conds returning/prevailing thru the end of the TAF period. Showers/storms will begin developing by this time, so a VCTS was mentioned at both sites beginning at 27/17Z. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...12 SHORT TERM...17 LONG TERM...15 AVIATION...12 For more information please visit our website at
Area Forecast Discussion
National Weather Service Miami FL
900 PM EDT Sat May 26 2018 .AVIATION... Trends in the model suggests more precipitation is possible through the night into Sunday. && .UPDATE... Raised rain chances overnight to nearly 100 percent as nearly certain widespread rain will continue. Latest convective band is pushing into far southern Florida nearly 1z and additional banding is likely toward early morning. 0z RAOB indicates increasingly favorable airmass for rotating updrafts as supplemented by HRRR and other CAMs. Target time for enhanced tornado risk appears to be 5z-13z, so will be continuing to closely monitor. SPC continues with Slight Risk of tornadoes and damaging winds south and west of a Naples to Miami line overnight, with Marginal Risk for remainder of CWA. Flood Watch and Small Craft Advisory continues areawide. High Risk of Rip Currents on East coast through Monday, with High Risk Sunday for Gulf Coast. Will be also monitoring for minor tidal inundation along the Gulf coast Sunday, particularly around high tide with is roughly midday. A Coastal Flood Statement is in effect along the Gulf coast where a foot or so of inundation is possible. Last but not least, Tropical Storm Warning in effect for outer Gulf Waters, beyond 20 nm offshore. Latest observations from buoys in the Gulf and also in and near the Keys should tropical storm force wind gusts are likely already occurring in this area. 8PM NHC advisory on Subtropical Storm Alberto reveals weak, disorganized storm with max. sustained winds of 40 mph, though highest winds are present well east of the center. Alberto should make its closest approach to South Florida during the morning Sunday. && .PREV DISCUSSION... /issued 349 PM EDT Sat May 26 2018/ DISCUSSION... The National Hurricane Center shows Alberto continuing to move north- northwestward over the eastern Gulf waters through the rest of the weekend. At the same time, an area of high pressure continues to remain over the western Atlantic just to the east of the Florida peninsula. This set up will allow for a south southeasterly wind flow to continue and it will keep a steady flow of deep tropical moisture in place through the Memorial Day weekend. With all of this moisture in place, rain chances will remain high through the rest of the weekend. Of particular concern is that for late tonight and Sunday, South Florida will lie under a region of upper-level divergence to the east of the deepening mid/upper level low pressure over the Gulf of Mexico associated with Alberto, as well as increasing low-level convergence and wind fields around the periphery of Alberto`s large-scale circulation. This synoptic setup is conducive for bands of rain and a few embedded thunderstorms to not only increase in coverage but also in intensity as they move north across the area. The end result is that our flood threat will increase beginning late tonight and continue through Sunday, and possibly Sunday night as well. The Flood Watch will remain in place at least through Sunday evening, and we will continue to closely monitor the threat of heavy rain and flooding even into Monday as Alberto continues to affect the northern Gulf coast. Along with the increasing threat of flooding, the potential for isolated tornadoes will increase late tonight in response to the strengthening low-level wind profiles, helicity values and increasing instability. The highest tornado threat appears to be late tonight and Sunday over Southwest Florida, but notable as well over Southeast Florida. This corresponds well with SPC`s marginal risk area over all of South Florida. Both of the latest GFS and ECMWF show Alberto moving across the Southeastern portion of the country early next week. This should also allow for a deep swath of moisture across South Florida as the flow should remain out of the south southwest at least through the middle of the week. By the end of next week, the swath of deeper moisture should slowly move northward out of the region, which should allow for a return to a more typical summertime pattern with scattered showers and thunderstorms developing along the east and west coast sea breezes. MARINE... The offshore Gulf waters are under a Tropical Storm Watch through midday Sunday due to its closer proximity to the outer tropical storm force wind field. Wind speeds will be between 25 and 30 knots across the Gulf waters, with higher gusts even outside of any rain bands. Over the Atlantic waters, South-Southeast winds of 20 to 25 knots tonight and continuing through late Sunday. Wind speeds gradually decrease to 15 to 20 knots late on Memorial Day, except over the offshore Gulf waters where winds will remain around 20 knots. A Small Craft Advisory will be in effect for all the coastal waters through at least Sunday night. BEACH FORECAST... Tides have been running about a half-foot above normal along the Southwest Florida coast based on data from NOAA tide gauges. As Alberto moves northward over the eastern Gulf, consensus of the latest model guidance shows that the water levels could go up a little bit more, as much as 1.5 to 2 feet above mean higher high water (MHHW) across portions of the Southwest Florida coast during the high tide cycle Sunday morning through midday. This will allow for the possibility of some minor coastal flooding and minor beach erosion especially in the vulnerable areas along the Collier County coast. We will continue to monitor this, however if this trend continues, a coastal flood statement will need to be considered for Sunday. There will be a high risk of rip currents along the Atlantic Coast beaches through Sunday evening. The threat for rip currents will also begin to increase late tonight and Sunday along the Gulf coast beaches, probably to a high risk. && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 73 83 75 84 / 90 90 60 90 Fort Lauderdale 75 82 77 83 / 90 90 70 80 Miami 74 83 75 84 / 90 90 70 80 Naples 72 84 74 85 / 90 80 60 80 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...Flood Watch through Sunday evening for FLZ063-066>075-168- 172>174. High Rip Current Risk from 8 AM EDT Sunday through Monday afternoon for FLZ069-075. High Rip Current Risk through Monday afternoon for FLZ168-172- 173. AM...Small Craft Advisory until 8 AM EDT Monday for AMZ610-630-650- 651-670-671. GM...Tropical Storm Warning for GMZ676. Small Craft Advisory until 8 AM EDT Monday for GMZ656-657. && UPDATE...23/SK DISCUSSION...55/CWC MARINE...55/CWC AVIATION...67/MT BEACH FORECAST...55/CWC
Area Forecast Discussion
National Weather Service Melbourne FL
930 PM EDT Sat May 26 2018 ...Flood Watch Remains in Effect for East Central Florida Over the Holiday Weekend... .UPDATE... Tonight...Increasing low level southeast winds have moistened the atmosphere back up after the brief dry intrusion from the east. Areas of light rain and isolated showers have been spreading northwest across the region. However, deep convection has remained well to the south closer to Alberto. As the circulation lifts north across the eastern Gulf of Mexico, moisture will increase further across the local area, and outer bands should push towards our southern counties. The HRRR model shows low level shear increasing too, so will have to watch for rotating cells over the Atlantic and near the Treasure Coast/Okeechobee in the pre-dawn hours. A threat for heavy rain also exists with this band of convection. The HRRR and GFS show widespread precip coverage southward from about Orlando to Cape Canaveral. Have increased PoPs a little across the south half (60-80%) based on the latest model trends. Previous Discussion... Sun-Mon...Rain chances ramp up considerably Sunday (up to 90%) and remain high Monday (70-80%) as deep southerly flow to the east of Alberto transports a very moist tropical airmass with PW values of 2+ inches northward across the area. Heavy rainfall and localized flooding remain the main concerns from this system, with the potential for training bands of showers and storms moving northward across the area. Rainfall totals of 2-3 inches are generally expected through Sun- Mon across much of the area, with locally higher totals possible. A Flood Watch remains in effect for all of east central Florida during this timeframe. An isolated tornado threat will also exist across the region, mainly into Sunday, when low level helicity values are maximized to the east of Alberto. While wind threat continues to remain low for the area with Alberto`s forecast track, breezy S/SE winds will still be expected into Sunday, with stronger showers and storms having the potential to produce strong wind gusts. Cloudy to mostly cloudy skies will persist through the holiday weekend, keeping highs limited to the low 80s on Sunday and mid 80s on Memorial Day. Overnight lows will remain above normal with values in the low to mid 70s. Tue-Fri...Even as Alberto weakens after landfall along the northern Gulf coast, a moist plume of 2+ inch PW values will persist in a deep S/SW flow over the area. This will continue a wet pattern through at least Wednesday, with likely rain chances (60-70%) forecast across much of the region. Showers and storms will likely transition to becoming more diurnally driven, with greatest coverage in the afternoon each day. Into late week, models indicating a slight decrease in rain chances as deeper moisture shifts south and east. However, scattered shower and thunderstorm coverage will remain in the forecast each afternoon. Highs will range from the mid- upper 80s, with low 90s possible across portions of the area on Friday. && .AVIATION... Much more adverse conditions are on tap as even higher moisture associated with the circulation of Alberto advects into east central Florida overnight and Sunday. Recent HRRR model runs show widespread showers with MVFR-IFR conditions spreading to KSUA a little after 06z, then rapidly northward and reaching KDAB-KLEE a little after 12z. This is faster than shown by the most recent TAFs, so further adjustments in timing can be expected due to the very dynamic nature of convection around this developing tropical cyclone. If the recent HRRR model pans out, there should be a period of brief heating in the late morning and early afternoon, which would allow for a second round of convection. It may not be as widespread, but the HRRR shows wind gusts over 35 knots along the coast and a fair amount of lightning. && .MARINE... Tonight-Sunday...Hazardous conditions for small craft operation. Southeast-south winds will increase to 20-25 knots tonight and Sunday. Seas will steadily build and be a choppy 6-8 feet offshore and 5-6 feet near shore. In addition, widespread showers with embedded squalls will affect the waters. Gusts over 35 knots will occur with the squalls along with some lightning strikes. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Flood Watch through Monday evening for Coastal Volusia County- Indian River-Inland Volusia County-Martin-Northern Brevard County-Northern Lake County-Okeechobee-Orange-Osceola- Seminole-Southern Brevard County-Southern Lake County-St. Lucie. AM...Small Craft Advisory from 8 AM to 10 PM EDT Sunday for Flagler Beach to Volusia-Brevard County Line 0-20 nm. Small Craft Advisory from 8 AM Sunday to 8 AM EDT Monday for Flagler Beach to Volusia-Brevard County Line 20-60 nm- Volusia-Brevard County Line to Sebastian Inlet 0-20 nm. Small Craft Advisory until 8 AM EDT Monday for Sebastian Inlet to Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet 20-60 nm-Volusia-Brevard County Line to Sebastian Inlet 20- 60 nm. && $$ Lascody/Bragaw
Area Forecast Discussion
National Weather Service San Angelo TX
622 PM CDT Sat May 26 2018 .AVIATION... /00Z TAFS/ Expect VFR conditions at the terminals tonight and Sunday. 21 && .PREV DISCUSSION... /issued 245 PM CDT Sat May 26 2018/ SHORT TERM... (Tonight and Sunday) This morning`s ARW and occasionally the HRRR have hinted at a few storms across the southeast portions of the area this afternoon and evening, in an area where visible satellite showed a little bit of ACCAS this morning. Its also pretty close to the moisture axis the storm last followed. Still think that convection is unlikely, but hard to rule it out completely. Will add a mention of isolated convection to areas southeast of a Brady to Menard to Sonora line through sunset. Otherwise, hot and dry to continue. Approaching the 100 degree mark in some areas this afternoon, and all indications are that it will be hotter on Sunday. Lots of locations to see highs in the 100 to 103 range. LONG TERM... (Monday through Saturday) The main story going into the last week of May will continue to the very hot temperatures. The upper level ridge remains centered over West Central Texas next week...between an upper low over the Great Basin and a low pressure system over the eastern Gulf of Mexico. Periodic disturbances rounding the crest of the ridge will generate scattered showers and thunderstorms across the southern and central Plains...with any convection looking to remain well north of the forecast area. Otherwise, high temperatures each afternoon will approach or exceed 100 degrees. The hottest days of the week look to be on Wednesday and Thursday...when 850 MB temperatures rise to 31-32 C across the western half of the area. This translates to surface temperatures in the 100-105 range. Needless to say, the heat is on with not much rain in sight. && .PRELIMINARY POINT TEMPS/POPS... Abilene 72 100 72 98 / 5 5 0 0 San Angelo 73 103 73 101 / 5 5 0 0 Junction 71 100 72 100 / 20 0 0 0 Brownwood 72 98 71 96 / 5 0 0 0 Sweetwater 72 103 73 99 / 5 5 0 0 Ozona 70 102 72 100 / 5 5 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$
...Update to aviation forecast discussion...

.Discussion...(This evening through next Saturday) Issued at 240 PM CDT Sat May 26 2018 Unseasonably warm temperatures will be the story for the remainder of the holiday weekend, with the possibility of storms this afternoon and again midweek. Northeast Kansas was baking under a late May sun this afternoon with highs toping out in the 90s to even near 100 along the KS/NE border where a drier airmass promoted more efficient warming. Heat indicies were about the same throughout the region with dewpoints 10+ degrees higher further south. A band of cumulus clouds has developed across Brown and Nemaha counties in the last hour or so along the gradient between these airmasses where weak surface convergence was also noted. All 12Z HREF members and daytime runs of the HRRR has indicated that convective initiation will take place around 20-21Z in this region. With 2000 J/kg of MLCAPE but weak vertical wind shear, robust but short-lived cell clusters are anticipated along and east of a line from Marysville to Topeka this afternoon and evening, ending by 01-03Z as they propagate S/SW on the collective outflow boundary. With ample mixing today, DCAPE values of 1500-1800 J/kg will promote efficient downward momentum transport and downburst winds with any convective cell. Thus, cannot rule out a severe wind gust with any thunderstorm this afternoon. The threat for small hail will also exist given the degree of instability. High clouds spilling over the top of the approaching H300 ridge are progged to move into NE Kansas this evening and tonight, though all synoptic and short-range solutions are failing to resolve these clouds. Thus have leveraged satellite imagery tends to advect the cirrostratus shield in overnight. These clouds linger throughout much of the day tomorrow and call into question how high temperatures will climb in the afternoon. For now have kept the going forecast for near record to record highs, but there is some concern that high clouds may temper these readings by 2-4 degrees. The upper level ridge pushes east by Sunday night with SW flow for Monday and Tuesday. The cutoff low over the SW U.S. migrates northeastward for Monday into Tuesday, dragging a frontal boundary slowly eastward over the High Plains and Mid-Missouri River valley. This will serve as the focus for shower and thunderstorm development midweek, though confidence in timing and placement of these storms is on the low side. These storms may temper highs somewhat, but looks for continued above average temperatures throughout the seven day forecast. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 619 PM CDT Sat May 26 2018 VFR prevails at terminals. Despite the short term models showing convection forming near terminals, current radar and satellite trends suggest there is not enough focused lift or boundary to warrant a mention for VCTS through 02Z. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Skow LONG TERM...Skow AVIATION...Prieto