Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/20/18

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
612 PM EST Fri Jan 19 2018 .AVIATION... An amplifying longwave ridge over the central United States and increasing stability aloft will maintain relatively quiet weather throughout the period. Models are having a difficult time forecasting the amount of saturation that will occur in the near surface layer Saturday morning as there is some projected low level moisture advection from the south. With snowpack in place, model boundary layer schemes are very suspect and low confidence exists. Rap is much less bullish on prospects for fog development and very low cig heights. Have used the Rap as a guideline and instead, will call for a prevailing MVFR HZ at all sites around/after daybreak with MVFR cig heights taking hold throughout the day. /DTW THRESHOLD PROBABILITIES... * Moderate to High for cigs aob 5kft after 12Z Saturday. && .PREV DISCUSSION... Issued at 251 PM EST Fri Jan 19 2018 DISCUSSION... Upper level ridge spilling over into the Great Lakes region today. 12Z Minneapolis sounding revealed very warm air/near record, as 850 mb temp checked in at 11 C, and this narrow axis of warm air will be sliding through southeast Michigan this evening as a dry cold front slides through the northern Great Lakes tonight. Sufficient mixing/elevated southwest surface winds through the night expected to hold temperatures around 30 degrees. Remnant/weak 850-700 MB theta-e ridge axis sliding south through the CWA on Saturday, with renewed 850 mb moisture/theta-e coming out of the Midwest late in the day. Maxes will be determined by amount of low clouds around tomorrow, as there is a major difference between 12z NAM/GFS 925 mb moisture/temps vs 12z Euro/Regional GEM. Could see maxes ultimately end up anywhere from the mid 30s to mid 40s. Preference will be to lean toward partly sunny skies and milder temps (lower 40s), as ARW is not nearly as bullish with the 925 MB moisture/RH. Low level jet (925-850 MB) over the Ohio Valley Saturday night veering, and becoming a bit more west-southwest, and thinking the low level moisture sufficient to generate drizzle/light rain will struggle to make much inroads across the southern Michigan border through Saturday Night. None-the-less, if a sufficient depth of saturation occurs, with temperatures flirting around freezing mark, a slight chance of light freezing rain/drizzle appears warranted along/south of M-59. Higher dew pts coming over the frozen ground on Sunday will likely result in some fog, but dew pts only expected to be in the mid 30s, probably not high enough to support dense fog, prefer values closer to 40 degrees, but also the amount of snow cover remaining, if any, will factor in as we head into Sunday evening. Aggressive height falls spreading into the Plains on Sunday, and over the Midwest/Iowa by Monday Morning. Strengthening surface high over northern Ontario (1036-1038 MB) with the tightening low level baroclinic zone over Lower Michigan will present a better opportunity for freezing rain along/north of M-46 late Sunday night as drier sfc-925 mb easterly flow undercuts the moisture/warm advcection above. Low pressure traveling northeast from IA/MO into Michigan Monday 12Z to Tuesday 12Z will bring the likely chance for precipitation throughout both days. There are slight discrepancies regarding the track of the low as it traverses across Michigan, with the GFS/GEM taking the low over northern lower Michigan, while the ECMWF run places the low across central lower Michigan and into the thumb. Despite the discrepancies, 850 mb temperatures averaging 4 - 6 C and surface temperatures peaking in the low to mid-40s will support rain for precipitation seen throughout Monday. As the low continues to push northeast into Ontario, cold Canadian air will quickly wrap around the western side of the low, dropping 850 mb temperatures down to an average of -5C by 12Z Tuesday. As a result, precipitation is expected to transition from rain, to a rain snow mix, and eventually all snow throughout the Tuesday morning hours. Light snow will be possible throughout Tuesday, before tapering off by early Wednesday as low pressure pushes into the New England. Temperatures will return to season to slightly above seasonal norms behind the low, with daytime highs peaking in the mid to upper-30s through the mid-week period. Surface high pressure and ridging aloft will help keep conditions dry through this time, with a late week developing low pressure system bringing the next chance for precipitation by Saturday. MARINE... High pressure centered over the southeastern US will dominate the weather over the Great Lakes for the next couple days. Southwesterly flow on the northwestern edge of the high pressure will persist through today with winds staying generally around 30 knots or less. Winds will back to the south/southeast by Sunday afternoon and evening as the next low pressure system approaches and also brings increased chances for rain to close out the weekend. Rain chances continue on Monday with winds becoming elevated as the center of low pressure system enters the Great Lakes region. Anticipate winds to be somewhat tempered by the warm air advection with this system through the weekend, but winds could pick up out of the southwest when cold air rushes in on the back side of the system. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....CB DISCUSSION...SF/AM MARINE.......AA You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Gray ME
754 PM EST Fri Jan 19 2018 .SYNOPSIS... A weak ridge of high pressure will build into the region today with temperatures a bit warmer than yesterday. A milder flow and above normal temperatures follow for the upcoming weekend. A storm system moving into the Great Lakes will bring wintry precipitation Monday into Tuesday with temperatures warming. A cold front Tuesday night brings colder air back into the region. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 700 PM Update... Sharp temperature inversion over the region this evening keeping low level moisture trapped over the area and will be slow to clear overnight. Increasing southwesterly boundary layer winds beginning to push this moisture out of southwest New England and this trend will continue through midnight and the early morning hours with clearing from southwest to northeast. High clouds pushing into the region from the northwest will be around overnight and through the first half of Saturday. Some light returns on radar showing up across southern Quebec in weak over-running with surface obs showing scattered snow showers. HRRR bringing a brief period of snow showers through northern zones after midnight which may produce a quick dusting in places but nothing too impactful. Have made a few tweaks to temps/tds but temps showing little change and should be steady or slowly rising overnight. No other changes to current forecast attm. Prev Disc... Weak short wave that brought snow showers to the north earlier today has moved offshore and will be replaced with milder WNW flow aloft. Cloudy skies prevail this afternoon with 20s and 30s across the region. Warmer temperatures are in place to the SW over PA and NJ where stronger southerly winds were in place in the vicinity of a forming surface trough. To the north, low pressure was traversing through Ontario Province...and this may trigger a few light snow showers along the international border overnight. Weak short wave that brought snow showers to the north earlier today has moved offshore and will be replaced with milder WNW flow aloft. Overnight lows will drop into the lower 20s north to mid 20s south before rising as a non-diurnal temperature trend is expected with warm air advection regime building in. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... The morning will be followed by a weak cold front and modest cold air advection. Nevertheless, expect some melting to occur with readings in the 30s in the north to the mid 40s/near 50 in the south. There will be a continued threat for scattered snow showers in the mountains. This will mainly be across the northwest facing upslope regions of the higher terrain. Saturday night colder air will filter in to the north with temperatures dropping into the teens...elsewhere we`ll see lows in the 20s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Other than the overall theme of milder than normal in the extended...focus is mainly on next precip event. Trof is forecast to move onshore across the Wrn CONUS by tomorrow and track across the country with broad Sly flow ahead of it. At the same time high pressure is forecast to build across Quebec just ahead of the approaching storm. This general evolution is supported by ensemble guidance...with differences in positioning but consistent timing. The high pressure building in N of the approaching low, and positioning off to the NE is favorable for colder surface temps than currently forecast by NWP. I continued the trend of undercutting guidance for the Tue high temp with non-diurnal trend of slow warming Mon night. This brings a mixed bag of precip into play...especially Tue. Snow, becoming sleet, freezing rain, and even rain is all on the table. That being said. regional RAOBs have not yet had a chance to sample this wave over the Pacific, and that may change model guidance Sat and especially Sat evening. The GEFS and ECMWF EPS remain at odds regarding the location of that high pressure...which will be critical to ptype forecasts. Clustering of ensemble members hints that a S/WV trof that amplifies sooner over the Wrn CONUS tends to favor the colder solutions by the time it reaches the Northeast...possibly due to WAA processes having maxed out well to our W rather than nearby. So for I see no reason to deviate significantly from the previous forecast...which seemed reasonable. Beyond that event, high pressure builds back in with return flow gradually moderating temps upward thru the end of the week. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... Short Term...Mainly VFR conditions across the region, however northernmost regions such as HIE and HIE will likely have a period of MVFR conditions in lower stratus and -SHSN. Gusty SW winds will develop Saturday. Long Term...Generally VFR conditions set to prevail to end the weekend. High pressure will build N of the area while the next storm system approaches from the W. High is well positioned to keep cooler solutions in play...but widespread IFR conditions are looking fairly likely. All ptypes are a possibility...with SN at the onset Mon night...transitioning from SW to NE. Some coastal terminals...even as far N as MHT...may change to RA before tapering off Tue afternoon/evening. Will have to monitor LLWS as well...with light to NE surface winds...and SW flow aloft across Srn parts of the forecast area. Wly flow dominates Wed...with MVFR clouds and SHSN in the mtns near HIE lingering. && .MARINE... Short Term...Winds and seas will increase late tonight and Saturday. There will be a period of SCAs, especially out over the outer waters. Winds may approach gales, but we will only see 2-3 hours of them over the far outer waters. Therefore feel SCAs were more appropriate. Long Term...Winds and seas will increase ahead of the next approaching storm system Mon night into Tue. Gale force wind gusts are possible outside the bays...with SCA conditions likely continuing into the end of the week. && .HYDROLOGY... Several points along area rivers remain at high water levels...including the Kennebec River at Augusta. Please see the Flood Potential Outlook (ESFGYX) for more information about the flooding threat. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory from 6 AM to 6 PM EST Saturday for ANZ153. Small Craft Advisory from 1 AM to 6 PM EST Saturday for ANZ150>152-154. && $$
Area Forecast Discussion
National Weather Service Houston/Galveston TX
858 PM CST Fri Jan 19 2018 .UPDATE... Eight o`clock temperature observations are in the middle 50s along the coast and across the northern tier of counties this evening. The Houston metro observations were a touch cooler ranging from 50-52 degrees, as they were seeing the occasional break in cloud cover over the last few hours. Easterly winds will continue to veer overnight, and onshore flow will prevail by sunrise. The warm air advection pattern that is in place will continue to allow both temperatures and dewpoints to rise through the night as the coastal trough currently draped over Matagorda Bay stretching southward into the Gulf of Mexico, shifts eastward. Only minor changes made to the forecast in this update. Increased cloud cover over the region tonight as cloud decks continue to lower in height. Based off current observations and the progression of this coastal trough, also went ahead and increased dewpoints slightly and bumped up low temperatures specifically across our northern tier of counties. Patchy fog becoming areas of fog, is still expected to develop beginning in western counties and fill in eastward through the evening hours. Both the SREF and HRRR short term guidance are indicating potentially dense fog developing in the early morning hours between 06-08Z and continuing through the morning. The threat for sea fog also creeps back into the nearshore waters, Galveston Bay, and Matagorda Bay Saturday as ample moisture return and warm air is advected over these cooler shelf waters. Hathaway && .PREV DISCUSSION... /ISSUED 535 PM CST Fri Jan 19 2018/ AVIATION...[00Z TAF ISSUANCE] Water vapor satellite imagery shows upper level trough over SE Texas and this feature should be moving east tonight into tomorrow. Warm air advection pattern will continue regardless as a ridge builds over Texas in response to a deepening trough over the Desert SW. This means a rather moist airmass will remain in place supporting low ceilings/visibility. Tonight IFR and even LIFR conditions are expected areawide with passing showers. This continues tomorrow with possibly some improvement in ceilings to MVFR by afternoon. Ceilings drop again Saturday evening back to IFR. Visibility may be restricted to a mile or less in a few areas in the morning. Showers may also cause a brief drop in visibility. These conditions should continue into Sunday and not improve until a front pushes through late Sunday night. Overpeck PREV DISCUSSION... /ISSUED 354 PM CST Fri Jan 19 2018/ DISCUSSION... Warmer conditions with periods of rain and fog are expected through this weekend before a cold front arrives late Sunday. Afternoon surface analysis shows a coastal trough stretching from near Rockport to Victoria and south into the Gulf. East of this feature, scattered to numerous showers aided by lift from an upper low sliding across the region continue to build north and east this afternoon. Expect this activity to translate east through the evening and overnight hours as this upper low lifts towards the lower Mississippi Valley with the coastal trough also lifting inland and losing definition as this happens. Southerly flow will spread across the region tonight in response, allowing low clouds to fill in and patchy sea fog to develop along the coast. Inland fog development will also be possible this evening and tonight, especially as the coastal trough loses definition and weakens the surface pressure gradient/low level winds. High resolution guidance does indicate the potential for dense fog and will have to monitor short term trends for any development overnight. Periods of light showers will continue tonight through Sunday as the region remains under an increasing warm air advection regime. With shelf waters having cooled into the mid 40s to lower 50s, sea fog will also be possible during this time across the marine areas and along the coast as moisture deepens across the region. High temperatures will warm into the lower 70s by Saturday and the mid 70s by Sunday as low level southerly flow strengthens as a lee surface low ejects across the Central Plains. An associated Pacific front or dryline developing across North Central/Central Texas during the day Sunday may serve as a focus for thunderstorm development Sunday afternoon and evening, but increasing southwest flow aloft during this time may result in too much mid-level stability for widespread thunderstorm development. A strong thunderstorm cannot be ruled out along this boundary in the Brazos Valley before a cold front overtakes it Sunday night, but the aforementioned mid-level stability and the left front quadrant of a 120+ knot upper level jet located over North Texas indicate this potential may be farther north of the region. Numerous to widespread showers and a thunderstorm or two will develop along the cold front as it pushes southeast across the region Sunday night, before clearing the coast Monday morning. Surface high pressure and dry conditions build into the region Monday through Wednesday with rain chances returning to the coastal and marine areas by Thursday as deeper moisture pushes back into the region. Huffman MARINE... Coastal troughing moving east and active area of shows and a few thunderstorms will continue this evening as the trough shifts east with the upper level s/w. Winds over the coastal water will increase slightly the remainder of the afternoon with building seas. Will continue the SCA for the 20-60nm waters and SCEC nearshore. Fog threat increasing slightly tonight but better chances looks to be with lighter winds and higher dewpoints over the cold shelf waters Saturday afternoon/night. Persistent southerly flow with a 2-4 ft swell Saturday and Sunday. Cold front sweeps through Sunday night and winds gradually ramp up and will likely need SCA by Sunday midnight onwards through Monday afternoon. Showers and possibly thunderstorms with the FROPA. This should end any lingering fog threat. 45 AVIATION... Band of lower CIGS from near ARM-HOU-EFD IFR/MVFR at 21z and this is likely a good confirmation that ceilings will be dropping quickly this evening as coastal trough slides eastward. Patchy fog confidence is fairly high with lower VISBY probably in the CLL-CXO- UTS region. 45 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 54 69 60 74 47 / 30 20 20 60 70 Houston (IAH) 51 71 60 75 54 / 30 30 20 40 70 Galveston (GLS) 55 66 59 69 56 / 50 30 20 20 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CST Saturday for the following zones: Coastal waters from Freeport to the Matagorda Ship Channel out 20 NM...Coastal waters from High Island to Freeport out 20 NM. Small Craft Advisory until 6 AM CST Saturday for the following zones: Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM...Waters from High Island to Freeport from 20 to 60 NM. && $$ Discussion...08
National Weather Service New Orleans LA
357 PM CST Fri Jan 19 2018 .SHORT TERM... The upper level trough that brought wintry precip and bitterly cold temperatures continues to lift northeast. A piece of that trough was pinched off and is located in Texas. Increasing 500mb heights from the exiting trough and moisture/cloud increase from disturbance to the west will result in significant rises in nighttime lows. Expect a 15 degree jump in tomorrow lows and highs from today. At the same time, scattered showers will be possible as this week upper trough/low drifts east across the northern gulf coast. HRRR precip output shows light showers pushing into forecast zones along the Atchafalaya basin overnight. Therefore, have introduced slight chance pops west of a BTR to HUM line. Moving into Saturday, guidance is slightly higher than previous solutions but still quite a bit lower than older runs. Decided to bump up rain chances for areas west of I-55 but kept them at a halfway point between previous forecast of 20% and MAV/MET 40%. Additionally, sea fog will likely become an issue along coastal parishes of LA beginning late tonight as dewpoints rise into the mid 50s. Attm, it appears this will mainly be limited to areas west of the Mississippi River. Ridge will then build in Sunday which will stunt rain and allow continued warming. You may think summertime has come early on Sunday compared to last week when temperatures rise into the low 70s. .LONG TERM... The CWA may be looking at a few thunderstorms at the start of next week. Models show an upper trough tracking west across the southwest US Saturday and Sunday. A low will develop at the base of the trough and race northeast towards the Great Lakes Monday. This weather pattern typically brings a relatively thin line of showers with embedded thunderstorms through. Intensity shouldn`t be of much concern as instability and dynamics will not be very conducive for vigorous development. Temperatures will likely drop back down behind the front mid week, but only on the order of 10ish degrees with a quick rebound by the end of the week. MEFFER && .AVIATION... Weak upper level wave over east Texas will spread moisture amd ceilings over most terminals from west to east through this evening. Most will be around OVC080 but will lower to OVC050 this afternoon for KBTR and KHUM. These ceilings should remain rather stable at OVC050-060 through tonight. All terminals will show some possibility towards observing either -DZ or -RA by Saturday morning. At this time, rain chances remain slight. Therefore, will hold off adding precip to latter part of the forecast. 18 && .MARINE... High pressure will shift east through tonight bringing return flow back to the northern gulf tonight into Saturday along with some rain. Foggy conditions near the coast could develop Saturday night through Sunday morning and Sunday night ahead of the next cold front which will move through Monday. A stretch of strong northerly winds look to occur again behind this front through next Wednesday. A trough will develop over the gulf by mid week. This feature will prolong an easterly flow over the coastal waters from Wednesday through next weekend. 18 && .DECISION SUPPORT... DSS code: Green. Deployed: None. Activation: None. Activities: None. Decision Support Services (DSS) Code Legend Green = No weather impacts that require action. Blue = Long-fused watch, warning, or advisory in effect or high visibility event. Yellow = Heightened impacts with short-fused watch, warning or advisory issuances; radar support. Orange = High Impacts; Slight to Moderate risk severe; nearby tropical events; HazMat or other large episodes. Red = Full engagement for Moderate risk of severe and/or direct tropical threats; Events of National Significance. && .PRELIMINARY POINT TEMPS/POPS... MCB 40 64 51 71 / 10 20 0 10 BTR 41 66 54 72 / 10 30 10 10 ASD 41 65 52 70 / 10 20 0 10 MSY 46 66 55 70 / 10 20 0 10 GPT 40 63 50 66 / 10 20 0 10 PQL 36 65 48 67 / 10 10 0 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$
Area Forecast Discussion
National Weather Service Morristown TN
933 PM EST Fri Jan 19 2018 .DISCUSSION... Isentropic lift leading to widespread low-level clouds to our southwest on the western periphery of a low-level ridge. Have increased cloud cover in the forecast to be closer in line with current observations and trends. Believe that the current RAP does a good job at initializing current cloud cover and showing it moving into our forecast area tonight and Saturday. With 925-850mb clockwise winds around the low-level ridge and the ridge axis extending through our forecast area, believe WNW winds and upslope flow conditions will be probable for the mountains late tonight and Saturday with a slight chance of some drizzle across the higher terrain because of the orographic lift. May even have some patchy freezing drizzle late tonight across the higher terrain as lift increases near sunrise. With cloud cover expected to arrive across NETN/SWVA/SWNC latest tonight, expect these areas to be the coldest tonight with efficient radiational cooling until the cloud cover increases late. If cloud cover does stick around during the day on Saturday as the RAP and NAM indicate, max temperatures may be several degrees below MAV MOS guidance. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 30 54 37 64 / 0 0 10 0 Knoxville McGhee Tyson Airport, TN 29 51 38 59 / 0 10 10 10 Oak Ridge, TN 29 50 38 58 / 0 10 10 10 Tri Cities Airport, TN 22 49 36 57 / 10 10 10 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ JB
Area Forecast Discussion
National Weather Service San Francisco Bay Area
342 PM PST Fri Jan 19 2018 .SYNOPSIS...Cool conditions and scattered showers will continue through late tonight. Drier weather returns on Saturday. A band of rain, possibly heavy at times, moves into the North Bay Sunday evening spreading southeastward Sunday night into Monday morning. Rain returns during the middle of next week with showery weather lingering into late next week. && of 1:45 PM PST Friday...Near term conditions have not changed much from this morning. Cool and unstable airmass still resides over the Bay Area. As a result, instability showers continue across the region. Have not see any recent lightning, but given the convective nature and colder airmass these showers may be heavy at times and contain small hail. A few spotters have confirmed small hail close to pea size hail. Current temps of some of the higher peaks are hovering right around 32 degrees. Therefore, any passing shower could drop some snow on the highest peaks. Latest HRRR and local WRF models keep instability showers through late tonight and current forecast will reflect this. Brief ridging develops over the Bay Area on Saturday with no precip expected. Despite drier conditions temperatures will still remain cool with highs mostly in the 50s and higher peaks in the 40s...about 5 degrees below normal. The ridging quickly diminishes on Sunday as the next system takes aim at the Bay Area. Latest model timing brings a weakening Atmospheric River into the North Bay between 12-18Z and then gradually spreading southward through the day. There could be a brief period during Sunday afternoon/evening where moderate to heavy rain may develop over the North Bay. Of greatest concern would be intense rain in short period of time impacting the burn scars. As of now it doesn`t appear to be a major concern, but something to monitor as Sunday gets closer. Rain chances will continue well into Monday with scattered showers remaining. Storm total rainfall from Sunday into Monday will be greatest over the North Bay 0.75-1.25"...SF/Santa Cruz Mts 0.25-0.75"...less than 0.5" elsewhere. A brief respite is possible late Monday into early Tuesday, but another system will bring additional rain to the region. It appears the storm door remains open with a decent cold front and more rain moving through Wednesday into Thursday. Cool and chilly weather will continue through Friday. && of 3:42 PM PST Friday for 00Z Saturday TAFs. VFR conditions are expected to prevail at most terminals through the period. The usual exception will remain KSTS where locally dense morning fog is forecast. Visible satellite imagery from GOES-East reveals scattered cumulus clouds distributed throughout the district. Expect the cumulus coverage to decrease heading toward and beyond sunset with the loss of daytime heating. Additionally, can`t rule out a stray shower or brief heavy downpour at the terminals over the next 3 to 6 hours. Will continue to monitor and amend as necessary. Vicinity of KSFO...VFR conditions are expected to prevail. FEW/SCT cumulus clouds around 3-5k ft AGL will continue to intermittently pass over the terminal through sunset, which may produce a locally brief shower. Will continue to monitor and amend as necessary. West winds 10 to 15 kt this afternoon will gradually diminish through the evening. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR conditions are expected to prevail for much of the period with FEW/SCT cumulus clouds through sunset. KMRY could see some overnight SCT clouds below 3,000 ft AGL that could potentially bring tempo IFR conditions to the terminal, but confidence is too low to include in the TAF. Will continue to monitor and amend as necessary. && of 03:28 PM PST Friday...Swells are slowly beginning to decrease across the coastal waters and will continue to do so over the weekend. However, moderate swells and increasing winds will still create hazardous conditions. Scattered showers continue to move over the waters. No lightning has been observed thus far over the forecast area, but a slight chance of thunderstorms still exists through this afternoon. Some cells may contain small hail. Winds will turn southerly and increase on Sunday morning ahead of the next system. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...High Surf Warning...CAZ006-505-509-529-530 SCA...Pt Reyes to Pigeon Pt 0-10 nm SCA...Pigeon Pt to Pt Pinos 0-10 nm SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm SCA...Pt Arena to Pt Reyes 0-10 nm SCA...Pt Arena to Pigeon Pt 10-60 nm SCA...Rough Bar Advisory for SF Bar SCA...Mry Bay && $$ PUBLIC FORECAST: MM AVIATION: Rowe MARINE: AS Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Charleston WV
716 PM EST Fri Jan 19 2018 .SYNOPSIS... With high pressure passing south of the area, a southwest flow will bring milder air through the weekend, with a warm front passing Saturday. A strong cold front crosses late Monday. && .NEAR TERM /THROUGH SATURDAY/... As of 705 PM Friday... Watching the stratus deck in the Tennessee Valley this evening and the implications here overnight. The NAM and RAP models seem to have a good handle on this in their respective soundings. They bring this deck into parts of the area late through significant moistening in the H9 to H875 layer, primarily along and east of the Ohio River. As a result, I have increased sky grids considerably late and carried this deck through much of Saturday east of the Ohio River. Tweaked hourly temps tonight to show a quick fall in the hollers and sheltered valleys versus the hilltops. Once the clouds move in, temps should level off and rise toward morning. As of 200 PM Friday... A ridge of high pressure remains in place with the center of high pressure over the north central Gulf coast providing dry weather to start the near-term. Brilliant sunshine and modest low- level warm air advection warms us nicely into the 40`s across lowland locations this afternoon. Decoupling tonight a little tougher than last night with SW flow picking up aloft, but still a decent bet in the most deeply incised, sheltered valleys. Models are still struggling to latch onto any one solution at this point. So have chose a middle-of-the-road approach favoring cooler temperatures in low spots. Tomorrow, moisture starts streaming in from the west/southwest providing some low-level clouds/stratus to start. Low-levels and eventually mid-levels saturate through the day, particularly across the northern zones. So, have decided to introduce drizzle Saturday afternoon. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 230 PM Friday... A warm front moves towards the area late Saturday night with overrunning. Forecast soundings are indicating a period of possible drizzle and fog as the warm moist air starts to push in. In the Northeast mountain valleys, some areas could be below freezing and may have a period of freezing drizzle or fog before we eventually warm early Sunday morning. Warm frontal light rain will continue on Sunday, with very light amounts expected. Temperatures Sunday will just up into the mid to possibly upper 50s. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 245 PM Thursday... Strong cold front will push into the Ohio Valley Monday afternoon. POPs increase quickly after 18Z Monday and widespread rain will overspreads the region Monday night. Thinking amounts should only be a half in or less in most places, but on the high end, maybe three quarters of an inch could fall in some spots. Cold air will push in behind the front on Tuesday and could see a changeover to snow, especially in the mountains, but moisture will be limited. Flow aloft settles back into a zonal pattern for the back end of the extended forecast. High pressure and warmer air should work back in by the end of next week. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 710 PM Friday... VFR conditions thru 06Z amid light southwesterly surface winds. Thereafter, low level moisture will increase with low stratus building into the area from the Tennessee Valley. This should allow MVFR cigs to develop across most terminals, except KPKB, in the 09 to 12z time frame. This stratus will linger through much of Saturday and perhaps lower during the afternoon, especially at KBKW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE: High. ALTERNATE SCENARIOS: Timing onset of MVFR cigs may vary an hour or two. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 CRW CONSISTENCY H H H H H H H H H M M L HTS CONSISTENCY H H H H H H M M M M L L BKW CONSISTENCY H H H H H H H H H M M L EKN CONSISTENCY H H H H H H H H H H M L PKB CONSISTENCY H H H H H H H H H M M L CKB CONSISTENCY H H H H H H H H H H H L AFTER 00Z SUNDAY... IFR possible Saturday night with fog and drizzle...and again Monday/Monday night with rain. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...26/MC NEAR TERM...30/MC SHORT TERM...MPK LONG TERM...MPK AVIATION...30