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

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
558 PM CDT Mon May 4 2020 .AVIATION... Northeast winds at 20 to 25 knots with higher gusts will be common until a couple of hours after midnight when winds will come down to 10 knots or less. Winds will turn to the southeast and south at DHT and GUY toward the end of this forecast. Skies are expected to remain VFR. && .PREV DISCUSSION... /Issued 335 PM CDT Mon May 4 2020/ SHORT TERM...Tonight through Tuesday Night... In the zonal flow aloft, a shortwave is progged to come through the Panhandles tonight. While this can provide some uplift, models are mostly dry except for the HRRR. Model soundings show very dry air through the column and when moisture is present, there is an inverted V. So for now have left out pops as thinking if the one shower in the far northwest of Cimarron County does develop like the HRRR suggests, it`s likely to just be virga and bring gusty winds. Otherwise for tonight, the surface low has already moved off to our east and the pressure gradient looks to tighten up this evening, causing winds to increase through midnight. After midnight the pressure gradient relaxes and winds ease as surface high pressure settles in. With the northerly flow in place, tomorrow will finally see cooler temps that will be more spring like. As the high pressure slides eastward, winds return to southerly flow which will help maintain overnight lows in the 40s. Beat LONG TERM...Wednesday through Sunday Night... Weak high pressure south of the Four Corners area will provide warm temperatures and northwest flow to the Panhandles. Wednesday looks to be a dry day with highs in the upper 70s to mid 80s. Models hint at increased 850-700mb moisture advection Wednesday night into Thursday morning. That increase in low level moisture, in conjunction with a shortwave under the northwest flow will aid in possible lift to get some nocturnal storms overnight Wednesday night into Thursday morning. That being said possible dryline setup across the Panhandles in the afternoon, with the eastern Panhandles in play for strong to severe storms. Areas east of the dryline have plenty of CAPE/Shear/Helicity to work with to have all hazards in play. However, not all models agree with this solution, as some suggest the surface low will be further south allowing for winds to be more out of the northeast. This will likely shut down the severe weather threat, although there might be a small chance with the incoming cold front Thursday night into Friday morning. Cold front will bring temperatures back down into the 60s to lower 70s on Friday. Main upper level trof associated with this front will be centered over the Great Lakes region. As this amplifies over the eastern CONUS, high pressure will strengthen over the western CONUS. This will bring increased northwest flow and warm temperatures to the Panhandles through the weekend. Possible northwest flow thunderstorm setup over the weekend. Will note that a slight shift of the ridge to the east or west will play a significant role on the highs being warmer or cooler, as the Panhandles currently sits right between the two air masses. Weber FIRE WEATHER... Elevated Fire Weather across the extreme southern Panhandle, mainly south of I-40 for the rest of the day. Cold front wind shift out of the northeast expected this evening. Some areas might see brief elevated conditions due to the increased winds, however the relative humidity should recover quickly behind the front. Weber AVIATION... 18Z Issuance...All sites look to remain VFR through the period. Northerly winds will remain through the next 24 hours. Expecting gusts of 20-30kts during the afternoon hours then increasing to 30-40kts from 02Z to around 08Z. Winds should die off after that to AOB 15kts. Beat && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 15/29
Area Forecast Discussion
National Weather Service Caribou ME
1206 AM EDT Tue May 5 2020 .SYNOPSIS... Low pressure will slowly exit into the Maritimes through Tuesday. High pressure builds into the area Wednesday into Thursday. Areas of low pressure will cross the region Friday into Saturday. && .NEAR TERM /THROUGH TUESDAY/... 1210 AM Update: Snow is falling across the St. John Valley down into NE Aroostook County as temps fall into the lower 30s. The latest HRRR was doing per the radar trends and obs. Precip pinwheeling around the upper low and will continue overnight across the northern and eastern areas. Kept precip chances high across these areas given that the best convergence and forcing situated across these areas. Could see a coating of snow w/up to 1/2 of an inch of snow in the higher terrain overnight, mainly in grassy areas. Hrly temps/dewpoints were adjusted matching the latest obs. Loaded in the ADJLAV through the overnight period as this guidance was matching up closely to reality. Previous discussion: Cold upper level low will continue to pivot over the region overnight. The added lift and forcing has produced some showers and isolated thunder this afternoon. There was also a report of pea sized hail near Oxbow, ME with one cell with a trace accumulation. Expect forcing and cold air aloft to move south and produce isolated thunder potential as surface temps remain warm near 60F amid breaks in the cloud cover Downeast. The environment will stabilize this evening, with a few scattered showers overnight. Across the north, temperatures have remained a bit cooler as cloud cover has remained in place today. Temperatures will fall to around freezing tonight, especially across higher elevations, resulting in some snow showers. A dusting can`t be ruled out in locations that cool the quickest and transition earlier. Upper low will slowly begin to exit through Tuesday. Some residual moisture will be in the region, and the chance for showers again increases Tuesday afternoon. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... Upr lvl low wl be ejecting twd the Maritimes Tue night with cyclonic flow continuing acrs the northern areas Tue evening. Showers wl diminish drg the late evng hours as upr lvl ridge begins to build in fm the west. Slight gradient wl allow winds to rmn up drg the overnight hours with a fairly nice day on tap for Wednesday. Upr lvl ridging wl dominate the region drg the day with some high clouds drifting thru the area at times. Max temps wl be just blo normal acrs the north with nr normal temps for Downeast. By Wed evening H5 low wl thru the the mid-Atlantic states with sfc low positioned just off of the Virginia Capes by 00z Thu. It wl move into the Atlantic drg the overnight hours with ridge of high pressure preventing much in the way of rain fm the coastal low impacting our area with the exception of far srn zones. With the upr trof linger over rmndr of the area expect that isold-sctd showers could develop at anytime Thu aftn with a little bit of diurnal htg. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Models begin to go off the rails at the start of the long term due to upr lvl pattern. 12z EC much more progressive with the upr low ovr the northeast over the weekend with GFS hanging it back until later Sunday. At the sfc this leads to strong low pressure crossing the NY Bight Fri evening with GFS keeping it offshore and only bringing pcpn onto Downeast coast Fri night into Sat morning. Meanwhile latest EC brings 984mb sfc low thru srn Maine by 12z Saturday bringing pcpn into the entire area Fri night and Saturday. Due to the discrepancies have capped pops at 50% but cannot rule out wintry pcpn, mainly at higher elevations on Saturday morning. Still plenty of time to make adjustments as model come more into line with one another over the week. Upr trof wl continue to swing thru the northeast part of the U.S. with chc pops continuing thru the end of the long term. Blo normal temps wl continue into early next week and possibly beyond. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... NEAR TERM: Northern TAF sites with rain showers will transition to a mix of rain and snow this evening and overnight. FVE will continue to go in and out of MVFR/IFR ceilings before trending towards MVFR after midnight. KCAR and KPQI will also see some snow mix in as ceilings go low MVFR or IFR tonight. Further south, precip will remain rain with BGR and BHB expected to remain VFR with winds increasing from the NW. VFR at the Downeast terminals Tue with MVFR at the northern Taf sites in Aroostook County, with brief IFR possible in any showers. SHORT TERM: Tue night...MVFR in the evening at Downeast terminals improving to VFR after midnight. Northern terminals remaining MVFR thru daybreak Wed. NW 5-10kts. Wed-Thu....Mainly VFR at all terminals. N 5-10kts gusting to 15kts Wed afternoon becoming light N Wed night then N 5-10kts Thu afternoon. Thu night...VFR dropping to MVFR by Fri morning at all terminals. Lgt winds. Fri-Sat...Very low confidence in this period with vsby restrictions expected Friday into Friday night in -ra or light mixed precipitation. && .MARINE... NEAR TERM: Wave heights will remain below SCA criteria, but NW winds will gust around 25 kts late tonight through Tuesday morning and a small craft advisory is in effect for the coastal waters. SHORT TERM: Winds and seas below SCA levels through the period. May see swell move in later Friday ahead of potential low pressure system over the outer waters. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 11 AM EDT Tuesday for ANZ050-051. && $$ Near Term...Hewitt
Area Forecast Discussion
National Weather Service Wilmington NC
815 PM EDT Mon May 4 2020 .SYNOPSIS... Low pressure approaching from the west will track over a remnant front, to produce morning showers across the area. A stronger front will cross the coast Wednesday, opening the door to cool Canadian high pressure Thursday into Friday. Another cold front arriving Friday night will bring even cooler air this weekend. && No significant changes as yet, convection will increase late tonight as an impulse approaches, teaming up with a remnant surface boundary, which it will pull northward as well, over the area into early Tuesday, mainly from 4am-9am before moving north and east of the area, including the remnant front. Will retain TSTMs as instability aloft will be present, and the added contribution from low-level frontal convergence. Outside of convection, low level winds relatively light, so any severe threat, would remain localized early Tuesday. && .NEAR TERM /THROUGH TUESDAY NIGHT/... Dry cold front continues to push south across SC this afternoon but it is expected to stall by this evening. HRRR has consistently shown scattered showers and a few tstms moving across primarily the northern zones overnight into Tuesday morning. This activity is likely a result of an impulse aloft coupled with the lingering H925- 850 boundary expected to be draped across the forecast area. Have bumped POPs upward in these areas during this time as a result. The warm front may struggle moving quickly to the north during Tue with a wedge-like pattern in place across NC but will likely make a better push to the north as low pressure moves from the western Carolinas to the eastern Carolinas by Tuesday night. Decent spread between MAV/MET numbers given positioning/timing of the warm front. Currently favor a blend toward the warmer MAV numbers. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Cold front poised to push offshore Wed AM, commencing a period of cooling and drying. Wed may end up being a relatively nice day. Although the front moves offshore in the morning the cold advection does not ramp up until Wed evening, when the 5h trough arrives. Once the cold air arrives it will do so with authority. Temps near climo Wed will tumble Wed night. Lows will end up some 12 to 15 degrees below climo, even with northerly winds 10 to 15 mph. Cold advection shuts off on Thu, but not even the high May sun angle will help. Highs will struggle to hit 70 with most areas 10 to 12 degrees below climo. Air mass starts to modify Thu as surface high, west of the area, shifts southeast. Temps Thu night still end up well below climo, but weak return flow setting up may be enough to take the edge off the cold. Skies will be clear, but a bit of southerly wind will keep radiational cooling from being maximized. Lows will once again end up in the mid 40s, 10 to 15 degrees below climo. && .LONG TERM /FRIDAY THROUGH MONDAY/... High pressure off the coast Fri will setup a brief period of warm advection, with highs approaching climo. The warm up will be short lived with a strong cold front crossing the area Sat night, accompanied by scattered showers and possibly an isolated thunderstorm. High pressure will follow the front building into the region Sat, moving overhead Sat night and Sun, then offshore for Mon. - Only rainfall chances will be Fri evening, ahead of Fri night cold front. - Temperatures well below climo for the weekend with potential for lows in the 30s in places Sun morning. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Brief period MVFR ceilings possible 9z-15z, coincident with warm front showers lifting to the north and east, clearing trends aft 16z. Veering winds today, but 12 kt or less overall. Isolated TSTMs possible embedded in showers, some could be strong. NE winds 4-9 kt tonight near end of TAF cycle. Extended Outlook...MVFR ceilings Wednesday. VFR returns Thursday and holds into the upcoming weekend. && .MARINE... A cold front will stall across the SC waters this evening, then lift northward during Tuesday through early Wednesday as low pressure migrates from the western Carolinas to off the VA/NC coasts. As a result, veering winds are expected around 10 knots with seas 3 ft or less with the boundary stalled nearby. Speeds will increase again from the SW with warm frontal passage with potential Small Craft Advisory thresholds met Tuesday night in a SW fetch with choppy 4-6 ft seas. Scattered showers and a few tstms are possible, especially for the Cape Fear waters Tuesday morning. Additional chances of showers/tstms as the warm front lifts northward later Tuesday and as low pressure moves across eastern NC Tuesday night before shifting offshore. Cold front moves east of the waters early Wed with offshore flow in place Wed and Thu. Cold air is delayed until Wed night, with speeds Wed running 10 to 15 kt. Once the cold air arrives the offshore flow will pick up with potential for period of solid 20 kt at times Wed night and Thu. Surface high passes south of the area Thu night with light return flow Fri morning. Southwest winds will increase during Fri ahead of next cold front, crossing the waters late Fri night. Offshore flow sets up Sat as high builds in behind the front. Although cold advection is significant, gradient is rather weak. Offshore flow will be on the low end of the 10 to 15 kt range but could see gusts in excess of 20 kt at times. Seas 3 to 4 ft Wed build to 3 to 5 ft Wed night and Thu as offshore flow ramps up. Seas drop to 3 to 4 ft Fri and 2 to 3 ft Sat as wind speeds drop off. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ UPDATE...MJC NEAR TERM...SRP SHORT TERM...III LONG TERM...III AVIATION...8 MARINE...SRP/III
Area Forecast Discussion
National Weather Service Blacksburg VA
1008 PM EDT Mon May 4 2020 .SYNOPSIS... Warm air riding over the top of high pressure wedging down east of the mountains will bring widespread rainfall to the Appalachians and central mid Atlantic region late tonight and Tuesday. High pressure will then bring cool but quiet conditions to locations east of the Blue Ridge through midweek, but conditions in the mountains will remain chilly and unsettled with a chance of showers just about each day through Friday. && .NEAR TERM /THROUGH TUESDAY/... As of 1008 PM Monday... Made a few adjustments in temperatures for tonight into Tuesday morning. This evening 00z rnk sounding showed a very dry airmass in place with pwat 0.35 ins. Low temperatures overnight will vary from the upper 30s in the mountains to the lower 50s along the southern Blue Ridge mountains. Moisture will slowly increase tonight as high pressure wedges down the eastern slopes of the Appalachians. Have the onset of the rain showers around 2 to 3 am Tuesday morning in the west and then spread rain east across forecast area. The Day 2 Convective Outlook highlights a marginal threat of severe for portions of the western mountains. The main threats will be gusty winds, hail and locally heavy rains. The latest HRRR and NAM still support the potential for a thunderstorm basically west of I77. Questions remain whether clouds and rain will hinder instability and thunderstorm development. High temperatures Tuesday will range from the mid 40s in the cool wedge to around 60 degrees in western mountains. As of 805 PM Monday... Made some minor adjustments in temperatures for this evening into tonight utilizing the latest surface obs, their trend and blended in the NBM. Low temperatures overnight will range from the upper 30s in the mountains to the lower 50s along the southern Blue Ridge mountains. Moisture will slowly increase tonight as high pressure wedges down the eastern slopes tonight into Tuesday morning. Kept the onset timing of rain Tuesday morning,then spread it eastward during the day. More later tonight... As of 155 PM EDT Monday... After a pleasant evening, our brief period of pleasant weather will be coming to an end late tonight as high pressure wedges down east of the mountains and strong isentropic lift over the wedge generates widespread rainfall from the predawn hours into Tuesday. Can not rule out some elevated convection producing a rumble or two of thunder as well. It currently looks like the rainfall amounts will be spread out over a long enough period of time to limit potential hydro issues, so will not issue any headlines and monitor later guidance closely. As Tuesday wears on, some deeper convection may develop outside of the wedge to our west where some surface based instability will develop. This convection will then start pushing into the region early Tuesday evening and may have a small amount of unstable air to work with in our neck of the woods to present a severe threat as it encounters enhanced shear along the western periphery of the wedge. Confidence is not high that the convection will maintain itself as it pushes in and believe the greater threat will reside just a bit further upstream as indicated in the SPC day 2 outlook. Nevertheless, will be monitoring later runs of meso guidance closely to see if the situation changes. Lows tonight will generally be in the 40s. Temperatures Tuesday will be well below normal in the wedge with some locations in the heart of the wedge simply remaining in the 40s throughout the day, but low/mid 50s down around the VA/NC line and lower 60s far west. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 155 PM EDT Monday... Precipitation will remain ongoing for the start of this forecast period with a trough`s surface front exiting the area early Wednesday morning. As discussed in the near term discussion, with little remaining instability left, its not likely that deeper convection will persist into this period and make it beyond the far SW mountains, but confidence in this is not absolute. While the front will be gone, showers will remain possible for the west Wednesday as the trough pivots over the region. As the day goes on, moisture will become more confined to just the far NW slopes. With dropping temperatures behind this system, don`t be surprised to see a few flakes in the higher elevations before moisture shuts off. Thursday remains cool as sunshine and dry weather return with continued NW winds. For now, temperatures will remain above freezing, meaning no freeze warning needed for the west. Likewise, the wind will help scrap any formation of frost. That said, look for average to below average temperatures through the period with ample cloud cover, showers, and NW winds. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 155 PM EDT Monday... The cool weather pattern that starts mid work week is set to remain in place with continued pattern amplification. A trough arriving late Thursday will bring a first shot of rain for the period through Friday. This trough looks to be the deepest digging at the moment, bringing the coolest temperatures. That said, has the saying changed to, "May snow showers bring June flowers"? It looks like temperatures should drop fast enough as moisture lingers to bring more widespread snow showers for those west of the BLue Ridge Friday night into Saturday AM. Accumulation amounts are foggy at this point, but presumably any accumulation will remain confined to the western slopes at higher elevations, and even there accumulations will be low. With the snow will likely come freeze headlines as temperatures will drop below freezing west of the Blue Ridge. Continued NW flow Saturday into Sunday will keep temperatures well below average. Guidance suggests that winds will die off as PGF decreases, meaning that a widespread frost/freeze is of concern. Heading out of the weekend and into the work week, continued unseasonal pattern amplification means more chances for rain and cooler than usual weather. However, Monday looks to bring some warming recovery with it thanks to a SW wind setting in ahead of a new disturbance that will arrive outside of the forecast period Tuesday. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... As of 735 PM EDT Monday... Expect VFR conditions all sites through 06z Tuesday. Late tonight into Tuesday morning, conditions will trend to MVFR/IFR toward daybreak as low clouds and precipitation develop courtesy of warmer air running over high pressure wedged down east of the mountains. IFR/LIFR conditions in low clouds, rain, and some fog will prevail Tuesday into Tuesday night. An Isolated thunderstorm may be possible west of I77. Winds will diminish with loss of heating this evening into tonight. Will start to see northeasterly flow pick up toward daybreak especially east of the mountains at KLYH and KDAN. High confidence in ceilings, visibilities and winds during the taf period. Extended Aviation Discussion... Unsettled weather lingering into at least Tuesday night, with sub-VFR cigs/vsbys and rain. Anticipate scattered showers across the mountains and foothills into Wednesday with sub-VFR likely in the mountains through Wednesday evening. High pressure arrives Wed night-Thu for VFR before front moves in with more shower chances Friday though mostly expecting VFR with some MVFR in the mountains. Drier weather is expected Saturday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...MBS NEAR TERM...KK/MBS SHORT TERM...RR LONG TERM...RR AVIATION...KK/MBS