Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/14/20

Area Forecast Discussion
National Weather Service Charleston SC
1054 PM EST Thu Feb 13 2020 .SYNOPSIS... Cooler high pressure will prevail through through Saturday night. A series of upper disturbances will move through from Sunday into the middle of next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Intermittent ana-frontal light rains will continue overnight, aided by large scale forcing from the nearby 120-40 kt upper jet moving into the Southeast. Additional rain amounts will be limited however, given that much of the rain is falling from a mid level cloud deck. We have 30-50% PoP south and east, with 20-30% chances north and west. Both the HREF and the HRRR show a short wave arriving from the southwest closer to daybreak, and this supports higher PoP than we now have over areas near the coast and south of I-16 in Georgia. We will monitor for this possibility. A post-frontal trough will slide southward overnight as winds veer to the northwest and north, and this will allow for cold advection to overspread the region. This will be tempered somewhat by considerable cloud cover, but we still anticipate low temps that are at least 25-35F colder than it was during the day Thursday. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... The cold front should be well offshore by daybreak Friday. However, continued upper shortwave energy across coastal areas and lingering low-level moisture could allow for scattered showers to persist along the coast through mid-morning. Skies should then clear by early afternoon across most or all of the area. A considerably colder airmass will settle over the area with high temps in the upper 50s to lower 60s. Cold high pressure will remain over the area through Saturday, then it will shift off the coast Saturday night into Sunday. Moisture will increase substantially on Sunday as a result of return flow. Upper shortwave energy will result in coastal trough development late Saturday night, with increasing clouds and scattered showers on Sunday. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Generally low confidence through the period. A longwave trough should push offshore Sunday night followed by high pressure Monday. Increasing moisture and additional shortwave energy could bring scattered showers starting Monday night and continuing through much of the rest of the period as a cold front eventually moves through. Cannot rule out a few thunderstorms if instability can develop. Temperatures will likely be above normal until possibly Thursday if the cold front moves through beforehand. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Very intermittent light rains will continue behind the a cold front overnight, and maybe even into the early morning on Friday. While a brief period of MVFR ceilings could occur, VFR conditions look to prevail. The bulk of Friday will be rainfree, and as drier air works it`s way in, skies will become clear at both terminals during the afternoon. Extended Aviation Outlook: Restrictions possible Saturday night through Sunday as a coastal trough affects the area. Brief restrictions then possible Monday night and Tuesday as an upper disturbance moves through. && .MARINE... Tonight: Small Craft Advisories are in place for the Charleston County Atlantic waters and the Georgia waters beyond 20 nm. Winds begin the night westerly at no more than 10 or 15 kt, then veer around to the NW behind the cold front by 1 am. Cold air advection behind a post-frontal trough will allow for winds to clock around to the N or N-NE with increasing speeds late. Conditions will be close to advisory levels on the other marine waters, but the current thinking is that it`ll fall just shy. Small Craft Advisory conditions expected to continue through midday Friday over the Charleston nearshore waters and through Saturday evening in the offshore GA waters. && .CLIMATE... Record high minimums for Feb 13: KCHS: 61/1984 KCXM: 60/1927 KSAV: 64/1880 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 6 AM EST Sunday for AMZ374. Small Craft Advisory until noon EST Friday for AMZ350. && $$ NEAR TERM... SHORT TERM... LONG TERM...RJB AVIATION... MARINE... CLIMATE...
Area Forecast Discussion
National Weather Service Cleveland OH
1002 PM EST Thu Feb 13 2020 .SYNOPSIS... An Arctic cold front will move southeast across the area this evening. Arctic high pressure from the northern Great Plains region builds in on Friday and Friday night before moving off to the east on Saturday. A cold front associated with a low over southern Ontario/Quebec moves across the area on Sunday. && .NEAR TERM /THROUGH FRIDAY NIGHT/... Temperatures are definitely getting cold enough for lake effect snow to develop. The DTX 00Z sounding came in with H8 temperatures of -16C. We just need winds to align better to get more organized lake effect snow bands. For much of tonight these bands will remain disorganized and therefore limit their potential. Toward morning we may see some better organization, but questions remain on band placement and then the degree of dry air being entrained. Upstream dewpoints are below 0. It will definitely be a fluffy snow. So no confidence yet to make any changes with the Advisory. Geauga may be questionable. Erie has at least had decent snow this evening. HRRR and RAP show a Huron connected band affecting more of Ashtabula into Crawford during the second half of tonight. There are multiple bands off of Huron now, but it will not be until after midnight sometime before there is less shear. Therefore, no significant change was made to the forecast. Previous discussion follows. An Arctic cold front is approaching the lakeshore from the north and is clearly visible on the CLE radar this afternoon. We have noticed in the last hour or so an uptick with organization of a burst of heavier snow associated along the front which will be arriving into the Cleveland metro area around the evening rush hour. Temperatures will fall through the 20s with the passage of the front and any moisture on roadways may flash freeze this evening. High res near term models are in good agreement with this narrow band of snow moving across most of the area through early evening. We will have to monitor any potential for a snow squall along the front with visibilities dropping to 1/2 of a mile and gusty winds. Once the Arctic front blows through the area this evening, the Arctic airmass moving over the unfrozen waters of Lake Erie will ignite lake effect snow showers and potentially a few lake effect snow squalls. The orientation of te wind from the north or northwest will also bring down a Lake Huron fetch which the high-res models indicate that particular lake effect band will move to Erie County PA or Ashtabula County area tonight. The high res models all show a few lake effect bands tonight through Friday morning but there is medium confidence on exactly where the bands will be favored and they also will be moving around as the low level shifts. A few models pick up on a snow band for the areas west of the CLE metro area and a few show that band east of the metro. But in general we are expecting 1 to 3 inches possible across much of the primary and maybe secondary Snowbelt through the morning. We tried to highlight the areas that have the greatest potential of 3 to 5 inches of lake effect snow in the Winter Weather Advisory for Geauga and Erie County PA. This advisory may need to be adjusted or expanded if the Lake Effect Snow becomes better organized or shifts. The Arctic high pressure settles in later on Friday into Friday night. This will allow the surface flow to become weaker and shift to a westerly or even southwesterly flow by Friday evening. We expect much of the lake effect snow showers to come to an end by late Friday morning or midday. Despite clearing skies on Friday, temperatures will struggle to get out of the teens during the day. Wind chills will be below zero for both Friday morning and Friday night. Actual air temperatures both tonight and Friday night will likely be in the single digits aware from the lakeshore and urban areas. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Fair weather is still expected on Saturday as high pressure at the surface and aloft exits to the east and a trough at the surface and aloft approaches from the Upper Midwest and Upper Great Lakes. A southerly flow veering to west-southwesterly with height will result in warm air advection and contribute to afternoon highs reaching the lower to mid 30`s. Saturday night through Sunday evening, the trough at the surface and aloft will gradually traverse our CWA from west to east, with a weak accompanying cold front sweeping through Sunday evening. Simultaneously, light and isolated snow and/or rain showers are possible. High pressure at the surface and aloft should then build from the west during the predawn hours of Monday morning, allowing fair weather to return. Saturday night low temperatures should reach the mid 20`s to lower 30`s, while Sunday afternoon highs are forecast to reach the upper 30`s to lower 40`s. Sunday night should be a touch cooler, with lows in the 20`s for the whole region. && .LONG TERM /MONDAY THROUGH THURSDAY/... High pressure at the surface and aloft begins exiting our CWA to the east as a surface low develops from the Central Plains toward the Upper Midwest on Monday. Isentropic lift tapping into Gulf of Mexico moisture should allow snow and/or rain showers to affect most of our CWA. Afternoon high temperatures should reach the upper 30`s to mid 40`s. Isentropic lift and associated rain and/or snow showers continue Monday night as the surface low perhaps tracks from the Upper Midwest toward the Upper Great Lakes and the accompanying warm front sweeps north across our CWA. Aloft, the parent trough should begin settling over the Northern Great Plains and begin approaching our CWA. Monday night`s lows should mainly reach the mid to upper 30`s. The longwave trough continues overspreading our region from the Northern Great Plains and Upper Midwest on Tuesday, while the attendant surface low may track from the Upper Great Lakes to southern Quebec, allowing the trailing cold front to sweep east over our CWA. Additional periods of primarily rain are expected, with high temperatures forecast to reach the mid 40`s to lower 50`s prior to the cold frontal passage. Tuesday night through Wednesday night, an expansive surface high pressure ridge builds from the west. Aloft, the longwave trough should continue moving eastward over our CWA through Wednesday and should then be followed by a longwave high pressure ridge building from the west Wednesday night. This pattern will cause precipitation chances to decrease over much of our CWA. However, lake effect snows could target the snowbelt Tuesday night through Wednesday night as colder air settles over Lake Erie and our region. Tuesday night lows should reach the 20`s, while Wednesday afternoon highs should mainly reach the lower to mid 30`s. Wednesday night should be colder, with lows in the teens to lower 20`s. Fair weather should return to the whole CWA on Thursday as high pressure at the surface and aloft continues building over the region. Thursday afternoon`s highs should reach the mid 20`s to lower 30`s. && .AVIATION /00Z Friday THROUGH Tuesday/... Areas of snow will still be in the vicinity of the terminals this evening and early overnight as there is an upper trough yet to pass. The most intense snow right along the cold front will affect YNG/CAK at the start of the TAF period/00Z for a very brief time. After that snow will be between 1 1/2 miles and 5 miles. Toward morning, areal coverage will decrease and snow showers will be more lake effect oriented and therefore more hit or miss for CLE/CAK/YNG/ERI through Friday morning. Keep ceilings MVFR through the TAF, but could be some holes/breaks in the overcast as is seen upstream across MI. Low confidence in timing and how long those breaks would hold. Best chance would be for TOl as the others should fill in with lake stratus. Winds will be 10 to 15 knots from the northwest early this evening and then weaken overnight and shift more westerly for Friday. .OUTLOOK...Non-VFR possible at times Saturday night and Sunday with mixed precipitation. Non-VFR possible again on Tuesday. && .MARINE... Low pressure pulls away from New England and the Canadian Maritimes through tonight as it tracks east-northeast over Atlantic waters. An Arctic front trailing this low sweeps south across Lake Erie this afternoon. Behind the front, northwesterly winds increase to 15 to 20 knots over the entire lake and waves build to 3 to 5 feet in the central basin. A Small Craft Advisory is in effect from 5 PM today to 7 AM Friday for nearshore waters from Vermilion to Conneaut. As colder air overspreads Lake Erie, some freezing spray is expected amidst higher waves. Conditions improve quickly on Friday as a large area of high pressure builds east across the Eastern Great Lakes. The high shifts to the east on Saturday with southerly to southwesterly winds increasing to 15 to 25 knots ahead of the next low pressure system that will pass north of the lakes. Winds may approach Small Craft Advisory criteria, although the offshore flow will help keep the larger waves on the outer fringes of the nearshore waters. Conditions should improve gradually Sunday into Monday as the next area of high pressure builds gradually eastward across the lake. Monday night, winds should shift from southeasterly to southerly as a warm front sweeps north over the lake and the parent low tracks across the Upper Midwest and Upper Great Lakes. On Tuesday, a cold front should sweep east across Lake Erie as the low tracks toward Southern Quebec. Winds shift from southerly to westerly with the cold frontal passage. Small Craft Advisory conditions may return on Tuesday, especially east of The Islands. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Winter Weather Advisory until 10 AM EST Friday for OHZ013. PA...Winter Weather Advisory until 10 AM EST Friday for PAZ002. MARINE...Small Craft Advisory until 7 AM EST Friday for LEZ145>148. && $$ SYNOPSIS...Griffin NEAR TERM...Griffin/Oudeman SHORT TERM...Jaszka LONG TERM...Jaszka AVIATION...Oudeman MARINE...Jaszka
Area Forecast Discussion
National Weather Service Lubbock TX
459 PM CST Thu Feb 13 2020 .AVIATION... Primary concern will be decreasing ceiling heights and visibility reductions due to fog. In fact, there`s a risk that KLBB/KPVW may drop to below minimums in freezing fog around sunrise Friday morning. Indications are that things will be slow to improve Friday morning though VFR should return by the afternoon. && .PREV DISCUSSION... /issued 223 PM CST Thu Feb 13 2020/ DISCUSSION... Low clouds have been holding on across the northwestern South Plains and southern Rolling Plains behind the cold front that has pushed across the region. Surface flow will remain out of the east to southeast across the area through tonight into tomorrow morning and model soundings show this, combined with weak isentropic lift, will likely help produce patchy freezing fog or low clouds across the Caprock for Friday morning. Will continue mention of this possibility through the overnight hours but it may need to be adjusted to start earlier and end later if some of the higher-resolution model soundings are correct. Last couple of NAM, HRRR, and RAP forecast soundings all show the potential for low clouds and fog to linger across the Caprock through or past noon Friday which could impact high temperature forecast as well. Areas that have been under the clouds today have struggled to climb above freezing, especially where snow remains across the northwestern South Plains. This is the only area with a bit of snow left so the impact may not be as great tomorrow across the rest of the South Plains but it will need to be watched to see if highs will need to be dropped for Friday. We will finally see highs start to warm back into the 60s by Saturday moderated a bit by a weak cold front that the 12Z model runs now push into the southern third of the forecast area for the first time. Previous runs have stalled the front across the northern South Plains/Rolling Plains allowing the southern half of the forecast area to warm close to 70 degrees so there is still a bit of uncertainty with high temperatures on Saturday. By Sunday and Monday, southwesterly flow aloft will develop with a potentially breezy southwesterly surface wind developing each of those days as well. That will boost highs to near 70 for Sunday and Monday on the Caprock and mid to upper 70s for the Rolling Plains. Forecast for Tuesday and beyond continues to focus on the differences between the ECMWF and GFS. ECMWF brings a strong cold front through the forecast area by Monday evening while the GFS holds off until Tuesday morning. Next issue is the GFS increasing precipitation coverage late Tuesday night into Wednesday morning with the ECMWF holding off until Wednesday afternoon. Only consistent elements between these two models is that we will see cooler temperatures with highs in the 40s/50s for Tuesday and colder for Wednesday and potentially Thursday. Otherwise, too many differences to pinpoint when, where, and how much precipitation will fall not to mention what the precipitation type will be. Will keep mention of rain/snow mix for times temperatures are below freezing and mostly rain through the daytime hours except for Wednesday afternoon which will probably see the coldest highs for the week with readings in the low to mid 30s on the caprock and near 40 for the Rolling Plains. Also will keep PoPs just below model blend for Tuesday into early Wednesday morning because of the differences in timing between the two models, but then went with the higher chance PoPs for Wednesday night into Thursday which is when both GFS/ECMWF have the best agreement in coverage across the region. Jordan && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 99/99/26