Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/29/17

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
848 PM CDT Mon Aug 28 2017 .UPDATE... Issued at 847 PM CDT Mon Aug 28 2017 Skies will remain clear through the night with light winds. Current forecast looks good. UPDATE Issued at 659 PM CDT Mon Aug 28 2017 00z aviation discussion updated below. && .SHORT TERM...(This Evening through Tuesday Afternoon) Issued at 317 PM CDT Mon Aug 28 2017 Winds today ended up being stronger than forecast across central SD, so have been adjusting wind grids towards the latest HRRR runs which have been doing a good job capturing the higher winds. These winds will subside after sunset as we head towards continued clear skies overnight with a light southerly breeze. Once again lowered ABR cooler than guidance as winds will likely drop to around 5 knots or less towards sunrise. Very similar air mass over the region on Tuesday, so will likely see temperatures much like today as we continue to see mostly sunny skies. Expect highs to rise into the 80s once again, with parts of central SD flirting with 90 degrees. .LONG TERM...(Tuesday Evening through Monday) Issued at 317 PM CDT Mon Aug 28 2017 The upper flow will be dominated by a 4 corners high, with an eastern CONUS trough and thus mainly northwest flow aloft. There is a subtle ridge axis overhead so subsidence can be expected for most of the extended. There is a brief period where an upper trough passes across the northern tier of the CONUS that will briefly suppress the ridge, resulting in a short period with a chance for precipitation. Wind flow aloft is weak, but the GFS supports a 30- 40kt low level jet with the mid level trough passage mainly overnight into early Friday - so mainly overnight convection. The stronger low level flow will also be responsible for windy conditions Thursday into Friday. A second, northwest flow wave will follow, but at this time it appears to move overhead Friday night, effectively dislodging some cooler air with stronger northerly winds for Saturday. Another wave, this one in central Canada, will be too far away to bring moisture to the area, but it will result in an area of warm advection that looks to move in Sunday - too far out to significantly deviate from extended blended guidance but something to watch as it comes closer to fruition. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening) Issued at 659 PM CDT Mon Aug 28 2017 VFR conditions are expected through tonight and Tuesday at all locations. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Mohr SHORT TERM...TMT LONG TERM...Connelly AVIATION...Mohr
Area Forecast Discussion
National Weather Service Cleveland OH
1014 PM EDT Mon Aug 28 2017 .SYNOPSIS... Low pressure over the Midwest will slowly move east across the Ohio Valley through Wednesday. A second trough will pull a cold front south across the area as it moves across the Eastern Great Lakes on Thursday. High pressure will move south out of Canada behind the front on Friday, shifting to the east coast on Saturday. && .NEAR TERM /THROUGH TUESDAY NIGHT/... Minor updates to pops/sky cover, but no major changes to the forecast with the late evening update. Shower activity continues across the western part of the forecast area. HRRR has done a fairly good job with this setup, and continues to indicate isolated/scattered showers translating eastward into NE OH overnight as upper jet streak across the Ohio valley moves east/northeast. Expanded some slight chance pops eastward through the night. Otherwise, thunder potential is quickly coming to an end with the atmosphere stabilizing across the region. Original discussion... There is little change to the forecast through Tuesday night. Upper closed low moves little, fills and opens Tuesday into Wednesday. The pattern is essentially on hold with no upstream kick and waiting for low pressure/potential tropical storm to move up the east coast over the next couple of days. So scenario will be similar tonight and Tuesday with the bulk of the shower/scattered thunderstorm activity taking place west of a Cleveland to Wooster line and never really progressing east. Will keep 20 PoPs in for Tuesday night for any lingering shower with trough axis overhead. Will go with similar temperatures for tomorrow, lower and mid 70s. Upper 50s/lower 60s both nights. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... The area is between systems on Wednesday but increasing warm advection ahead of a cold front may produce a few showers/thunderstorms. The chances of thunder will increase ahead of the front, especially across the eastern half of the County Warning Area. The amount of moisture available to lift is in question so the coverage is uncertain. By Friday high pressure will build across the region with dry conditions anticipated. Wednesday should be the warm day of the short term with highs in the middle to upper 70s. Cooler thursday into Friday with highs mid 60s to mid 70s. && .LONG TERM /FRIDAY THROUGH MONDAY/... The long term begins Friday night with both the ECMWF and the GFS showing high pressure over the central and eastern Great Lakes while remnants of Harvey move slowly northeast through the Mississippi valley. Dry air will be in place across the region however deep moisture will be approaching from the ssw. By Saturday morning the GFS has the surface low over northern AR/srn MO while the ECMWF low is in western KY. Manual progs split the difference with the low on the AR/TN border. Both models agree however that moisture moves north in the area during the day Saturday as the surface high drifts to New England. Deep moisture remains into early Sunday before weak high pressure and drier air move in for the afternoon. Will have chance pops moving into the area from the south Friday night with chance to likely pops most areas Saturday. Highest pops again south of a Marion to Canton line. Will continue with chance pops Saturday night, highest southeast. Sunday will continue with chance pops southeast as moisture begins to pull east out of the area. Monday models show a cold front moving through the area from the northwest so will need a chance pop in for the day. High temps mainly mid and upper 70s. && .AVIATION /00Z Tuesday THROUGH Saturday/... Scattered showers and storms possible at the terminals through the period as an upper low slowly moves east across the Great Lakes region. The best chances for TSRA early in the period will be at KFDY and KTOL, with lesser chances at KCLE and KMFD, and primarily dry conditions elsewhere. A brief lull in convective activity possible overnight before redevelopment around daybreak Tuesday and again Tuesday afternoon. Some MVFR/IFR stratus may impact KTOL toward daybreak, but will keep ceilings MVFR at until confidence increases. Surface winds will remain out of the southeast through the period, becoming fairly light at most sites overnight. OUTLOOK...Non-VFR conditions possible through Thursday in scattered showers and tsra. Patchy morning fog for inland sites also possible. && .MARINE... Low pressure over SE Wisconsin will decrease as it moves toward Ohio. This will allow the pressure gradient to relax and decrease the winds Tuesday night into Wednesday. A cold front will sag southward into the area on Thursday with increasing southwesterly winds ahead of it. A large area of high pressure will build across the lake Thursday night into Friday. The strongest winds will likely be late Thursday into Thursday night with a small craft advisory possible. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Oudeman NEAR TERM...Greenawalt/Oudeman SHORT TERM...Mullen LONG TERM...TK AVIATION...Greenawalt MARINE...Mullen
Area Forecast Discussion
National Weather Service Midland/Odessa TX
627 PM CDT Mon Aug 28 2017 .DISCUSSION... See 00Z aviation discussion below. && .AVIATION... Isolated TS will dissipate shortly and will not affect any TAF sites. VFR conditions are expected through the period with northeast winds. Hennig && .PREV DISCUSSION... /issued 304 PM CDT Mon Aug 28 2017/ DISCUSSION... Current radar is showing a few isolated showers moving southwest into the Permian Basin this afternoon. The HRRR indicates this activity will persist through peak heating then quickly dissipate. They are moving quickly and there is little shear so no flooding or severe weather is expected. Models do not show any additional rainfall this week though their course resolution may not pick up some of these afternoon showers well. Have kept the forecast dry until the weekend but do not be surprised to see some afternoon showers this week. Dewpoints dropping into the 50s will let overnight lows stay below normal for the next few days. Model guidance appears to be handling highs better and have stayed at or slightly above MEX/ECE guidance this forecast period. Hennig && .PRELIMINARY POINT TEMPS/POPS... Big Spring 63 89 63 89 / 0 0 0 0 Carlsbad 65 88 63 90 / 0 0 0 0 Dryden 69 93 67 93 / 0 0 0 0 Fort Stockton 64 88 62 89 / 10 0 0 0 Guadalupe Pass 61 79 61 82 / 10 0 0 0 Hobbs 60 86 59 87 / 10 10 0 0 Marfa 56 82 53 83 / 10 0 0 0 Midland Intl Airport 64 89 63 89 / 0 0 0 0 Odessa 64 89 62 89 / 0 0 0 0 Wink 65 89 62 91 / 10 0 0 0 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...None. TX...None. && $$ 99/99/10
Area Forecast Discussion
National Weather Service Mount Holly NJ
917 PM EDT Mon Aug 28 2017 .SYNOPSIS... High pressure will remain over northern New England and southeastern Canada through early Tuesday. Meanwhile, an area of low pressure positioned near the Georgia coast this afternoon could develop into a tropical cyclone as tracks slowly up Southeastern U.S. coast tonight and Tuesday. The low is expected to reach the Outer Banks of North Carolina and then turn northeastward out to sea Tuesday night into Wednesday. High pressure briefly builds into the region Wednesday afternoon and night before a cold front progresses through Thursday afternoon and evening. High pressure returns Friday and Saturday. The next cold front will approach from the northwest on Sunday and eventually move through the region either late Sunday or Monday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 930 pm update: Made some minor adjustments to temps/dew points/winds/sky cover to account for latest trends. Otherwise, the forecast is in good shape. The 18Z GFS increased QPF amounts a little bit across the area, continuing the trend seen in other operational models today. Thus, the changes made to PoPs/Wx grids earlier seem OK at the moment. Previous (still relevant) discussion below... The 18Z NAM depicts the developing surface low just southeast of the SC/GA coast will progress northeast along the SC coastline this evening to near Wilmington, NC, by 12Z Tuesday. This is reasonably agreed upon by most of the guidance. However, with persistent onshore flow and increasing low-level isentropic ascent as the low makes its approach along the coast tonight, most models develop light rain well north of the low, easily reaching the Delmarva Peninsula by 12Z. Some guidance, including the HRRR and 18Z NAM Nest, suggests an even earlier onset, though I suspect the low levels will require some moistening before steadier precipitation reaches the ground. The 18Z NAM is notably dry, but it seems to have a dry bias on the north side of developing coastal systems (at least since the previous winter). Given the precipitation signal in most of the guidance at this point, feel that raising PoPs overnight (especially south of the Mason-Dixon Line) is appropriate. Increased the speed of increasing cloudiness tonight as well. Other main adjustment was to dew points, which were too high for the past couple of hours. Moistening of the low levels will probably be slower than progged owing to this bias so far this evening...another reason I suspect the high-resolution output is a little too aggressive bringing precipitation into the area by sunrise. Made slight adjustments to winds as well, mainly in accordance with recent trends, to more of an east rather than a northeast direction through the overnight. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... Made some adjustments to the short-term forecast this evening. Models are clearly struggling with the phasing process of the developing coastal low and the midlevel vortex moving through the Great Lakes on Tuesday. Run-to-run variability remains above average even at this close range to the event. A look at the 18Z NAM (which is mighty different than its 12Z counterpart) suggests that the low will pivot almost northward during the morning hours to the Outer Banks region, then rapidly progress east-northeastward as the vortex traverses eastward during the afternoon. This progression eastward is aided by a kicking shortwave trough moving through the Ohio Valley during the afternoon (aided by a developing/strong midlevel jet streak). Interestingly, another of these north-then-east pivots occurs after the short-term period, in association with the longer-wave trough becoming negatively tilted. Timing is everything here, and models notoriously struggle with the phasing process (note the general tendency to push the coastal low too far east the past several days). Feel the best approach is the "trend is your friend" approach to the forecast, which appears to be a somewhat farther northwest track and a somewhat stronger intensification of the low. With this in mind, main adjustments were to spread higher PoPs northwest, increase QPF in central/southern Delaware and far southeast New Jersey (based on a consensus of WPC/HRRR/NAM Nest/ECMWF/RGEM/GFS), and increase winds a little bit across most of the CWA. For storm-total QPF, areal averages are at or below a half inch northwest of I-95, 0.25-0.75 from I-95 to northwest of a Dover to Toms River line, and 0.75-1.75 southeast of this line. However, confidence is very low on totals because of the aforementioned model uncertainties. No changes to headlines at this time. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... The coastal storm is expected to move off the coast Tuesday evening to our south (exit point is likely north of Cape Hatteras and south of Virginia Beach) and then accelerate east-northeastward and out to sea through Wednesday. A slight trend was noted in the 12Z model guidance toward a stronger coastal storm with a track that is slower and closer to the lower Delmarva coast. Unfortunately, these trends put coastal areas at a higher threat for hazardous weather. Farther inland, impacts from this storm will be limited. Gusty E-NE winds around sunset Tuesday evening will back through the night, eventually becoming N-NE late. The strongest winds will be near the DE and southeast NJ coast where gusts to around 45 mph are expected to continue into the evening. A Wind Advisory covers this threat. Despite the potential for NE winds of 40-50 kt residing at 2- 3 kft AGL to expand well inland as the storm takes its closest approach to the southeast of us, weak lapse rates and lack of deep convection should inhibit these stronger winds aloft to mix down to the surface across inland areas. It is becoming more likely that the northwestern edge of the precip shield will be slower to depart, resulting in a continuation of rain Tuesday night, particularly over the coastal plain. PoPs were updated accordingly. The 12Z NAM appears to be the worst-case scenario in terms of rainfall and flooding risk, showing 1-2 inches in eastern PA and NJ and 2-4" in Delmarva. We went above WPC QPF, but not nearly as high as the NAM. Any heavy rain will likely be highly localized. On Wednesday, drier air advecting around the backside of the departing storm will yield breaks in the dense cloud cover from NW to SE during the morning. However, the development of stratocu will likely ensue after a few hours of stronger heating. The extent of the additional cloud cover in the afternoon is uncertain at this time but it could plausibly lead to mostly cloudy skies for some locations. No mention of rain in the forecast for Wednesday or Wednesday night with high pressure building into the mid Atlantic. The high quickly retreats off the Southeast coast by Thursday morning as a cold front approaches our area from the Great Lakes. This front is expected to arrive first in the Poconos by early afternoon, then the I-95 corridor by early evening and finally move off the coast before midnight. Attempted to add some timing detail in the forecast with the primary chance for showers and storms confined to just the few hours leading up to the fropa. Owing to a lack of deeper moisture and modest values from various instability indicies, thunderstorm coverage and intensity should be limited. After a week of seasonably cool conditions, temperatures on Thursday...the last day of meteorological summer...briefly warm up to normal with highs in the low to mid 80s. High pressure build back into the region late Thursday night and Friday. The high will continue to influence the area through Saturday. Below normal temperatures and dry weather can be expected during this time. The high should move offshore Saturday night-Sunday while a cold front approaches from the Great Lakes/Midwest. There are indications that moisture from the remnants of Harvey could be drawn downstream ahead of the approaching cold front and mid-level trough. This would increase our rainfall chances for Sunday and/or Monday. Kept PoPs low for now due to considerably uncertainty in the timing and location of these features. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. For the 00Z TAFs...VFR conditions across the region will deteriorate to MVFR from south to north after midnight into the mid-morning hours Tuesday. Sped up the timing of rain reaching the terminals, now generally in the 12Z to 16Z time frame, though confidence is low near/northwest of PHL. Rain is expected to last most of the day, especially southeast of PHL. CIGs should remain MVFR or lower through the rest of the period, with VSBYs possibly becoming sub-VFR at times as well, especially at MIV/ACY, where somewhat heavier rain is expected. Winds generally between 50 and 110 degrees near 10 kts tonight becoming 10 to 20 kts tomorrow with higher gusts, especially near the coast. OUTLOOK... Tuesday night...MVFR conditions expected to affect all TAF sites with the potential for IFR closer to the coast where a period of heavier rain is possible. E-NE winds veer to the N-NE late. Winds will be strongest toward the coast where gusts to 35 kt are possible at ACY. Wednesday and Wednesday night...Lingering MVFR ceilings in the morning should improve to VFR from NW to SE. Thursday and Thursday evening...Predominately VFR. A chance of showers and slight chance of thunderstorms. A wind shift from SW to NW is expected late in the day with a cold fropa. Thursday overnight through Saturday...VFR expected. && .MARINE... Made several adjustments to the marine forecast, including increasing seas through tomorrow night, based on this evening`s observations, and increasing the swells based on a combination of obs and recent model data. The next 24-36 hours will be rough on the coastal waters. Current seas forecast to be generally 6-9 feet through early morning, 7-12 feet through around midday, 8-15 feet tomorrow afternoon and evening, before a slow decline late Tuesday night. Wind forecast looks good and may only minor adjustments (mainly to timing of the peak winds). No changes to the headlines at this time. OUTLOOK... Tuesday night...Gale Warning continues for the southern New Jersey and Delaware coastal waters and lower Delaware Bay. The warning may ultimately need to be expanded northward to include ANZ450-451 if the storm continues to trend farther north. Elsewhere, a SCA is in effect. Raised seas by 3 to 4 ft above WaveWatch guidance after accounting for a low bias in the model in NE flow. Seas may reach 14-16 ft at 44009 by evening. Wednesday...SCA was extended into Wednesday for ANZ450-451. Winds may still be near 25 kt early in the day before quickly decreasing. Seas will take much longer to subside with long- period easterly swells continuing to impact the area even after the low departs. Wednesday night and Thursday...Winds expected to be below SCA threshold, but seas may remain above 5 ft. Thursday night through Saturday...Winds and seas below SCA criteria. RIP CURRENTS... No-brainer forecast here. With seas forecast to increase through tomorrow evening and onshore winds increasing to gale force in the southern NJ and DE coastal waters (and not far from gale force to the north), the risk of dangerous rip currents is high through tomorrow night. Combined with rough surf, entering the waters may be dangerous. Heed beach restrictions and closures from local officials. && .TIDES/COASTAL FLOODING... An onshore flow is expected through Tuesday night. While water levels will be on the increase, we are at the first quarter moon so astronomical tides are relatively low. It would take a surge of nearly 2 feet to cause widespread minor flooding along the coasts of Delaware and New Jersey. At this time, latest surge guidance does not show this, although met model trends over the last 2 days show a northward jog with the surface low. Because of this northward jog in the forecast storm track, in combination with onshore winds around 45 mph and building seas with wave runup expected, we feel mentioning spotty minor flooding is the prudent thing to do south of Little Egg Inlet. In addition, any rain falling at the times of high tide could be slow to drain right along the coast and backbays. Along with the high surf, beach erosion is expected on Tuesday and could persist into Wednesday with the continuation of long period swells. Across southern NJ and DE, where the beach erosion will be more significant, a High Surf Advisory was issued for Tuesday and Tuesday night. Refer to PHLCFWPHI for more information. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...High Rip Current Risk through late Tuesday night for NJZ014- 024>026. High Surf Advisory from 6 AM Tuesday to 6 AM EDT Wednesday for NJZ024-025. Wind Advisory from noon Tuesday to midnight EDT Tuesday night for NJZ023>025. DE...High Rip Current Risk through late Tuesday night for DEZ004. High Surf Advisory from 6 AM Tuesday to 6 AM EDT Wednesday for DEZ004. Wind Advisory from noon Tuesday to midnight EDT Tuesday night for DEZ003-004. MD...None. MARINE...Gale Warning from 6 AM Tuesday to 4 AM EDT Wednesday for ANZ452>455. Small Craft Advisory until 6 PM EDT Wednesday for ANZ450-451. Small Craft Advisory until 4 AM EDT Wednesday for ANZ430. Gale Warning from 6 AM Tuesday to midnight EDT Tuesday night for ANZ431. && $$ Synopsis...Klein Near Term...CMS Short Term...CMS Long Term...Klein Aviation...CMS/Klein Marine...CMS/Klein Tides/Coastal Flooding...