Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/10/18

Area Forecast Discussion
National Weather Service Boston/Norton MA
958 PM EST Fri Nov 9 2018 .SYNOPSIS... An intensifying storm tracks over the the Cape Cod Canal tonight. This system will bring moderate to heavy rains, potential flooding, and possible strong to damaging winds. Dry and unseasonably chilly temperatures follow Sunday into Monday. Another low pressure will bring a period of heavy rain to the region late Monday night into Tuesday, but there is a low risk for precipitation to begin as a brief period of snow or ice across the interior. Dry but unseasonably cold weather follows Wednesday into Thursday, before temperatures moderate some by Friday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 10 pm update... */ Highlights... - Flood Watch trimmed to focus on E / SE New England into Saturday - Wind Advisory for Cape and Islands continues - Monitoring convection / heavy rain closely S of LI approaching SE New England, likely impacting shortly after midnight into early morning Saturday. */ Discussion... Secondary low strengthening S of Long Island with observed pressure falls around 2 mb / hr. Providing a localized convergent focus of the warm-moist conveyor belt beneath broader diffluence aloft, seeing heavy rain and convective elements emerge. Strong SW 0-6 km shear and mean wind, line echo wave patterns emerging as discerned via WSR-88D. MRMS interpreted 1-hour rainfall rates of 0.5 to 1.0 inch given the progressive nature of the storm system. Storm system should lift NE through tonight at a rapid pace, exiting close to early morning Saturday. Heavy rain and damaging wind threats continue which are highlighted below. WINDS ... Focus ahead of the secondary low within the weak warm sector, marginal lapse rates. A focus on H95 winds. Will hold with the present wind advisory however there is some concern that even S areas of Bristol and Plymouth Counties in MA could reach wind advisory criteria if heavy rain is able to drag down faster momentum. S gusts upwards of 50 mph continue into early morning with the possibility of a quick SW burst immediately behind the secondary low as both pressure gradient and isallobaric forces advect colder air rearward allowing steep lapse rates and that opportunity for a quick mix down of faster momentum. Hence keeping the WIND ADVISORY for the Cape and Islands extended through Saturday. GALE WARNINGS for all waters throughout as well. H95-925 SE jet centered around 1 am over SE New England, especially Cape Cod and Islands with values over 55 to 65 mph. It`ll be interesting to see how much of this momentum will mix down to the surface. FLOODING ... Significant WSR-88D radar returns approaching from the SE out ahead of the secondary surface flow. Coupled pressure falls with anomalous precipitable waters upwards of 1.5 - 1.7 inches per latest RAP / SPC mesoanalysis, both the H925-85 moisture transport aimed at SE New England, trimmed the FLOOD WATCH to SE New England highlighting the region of greatest confidence for flooding rains. To the W, mid- upper level drying along with subsidence between the double-barrel low is contributing to a quick end to the rainfall over the NY Hudson Valley extending into W New England. Collaboration with other WFOs, watch was dropped W of the I-95 corridor. Column saturation up to 12 kft per latest RAP, deep column ascent given dynamics out ahead of the potential vorticity displacement along the 1.5 PVU surface, potent vortmax and accompanying diffluence aloft, undoubtedly some efficient rainfall production will occur over SE New England. Urban / poor drainage flooding, especially more so with leaf-clogged drains. Potential flooding of faster responding small streams and tributaries. Rivers running high as of late, so this water being added to the system will only exacerbate and/or prolonged any ongoing or forecast river flooding issues. Quick 1 to 2 inches, locally higher amounts. Greatest amounts focused in and around the Cape Cod Canal immediately E of the low track. CONCLUDING REMARKS ... With respect to emerging convection ahead of the secondary low, there is some concern for localized severe weather. Can`t rule out a brief tornadic spin-up through the greater confidence is out over the warmer waters further S/E. There`s a lot of helicity in the region in addition to low-level shear. If the lapse rates can steepen more than just marginal, then the damaging wind potential greatly increases. Watching closely for bowing segments within the line echoes that are approaching, looking for any potential book-end vorticies that may emerge in the NE quadrant of any bowing. Will handle any convective elements with short-fused severe / special marine warning products. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... Saturday... */ Highlights... - Wind Advisory for central/eastern MA and RI with Westerly gusts 45 to 50 mph. - Flood Watch continues into Sat with the likelihood of some area rivers and streams continuing to rise in the wake of the Fri night rains */ Winds... The low pulls rapidly northeastward and away from southern New England during Saturday morning, steadily deepening along the way. Negatively tilted upper trough sweeps thru southern Quebec/northern New England with an associated short wave pushing thru our area. This accompanied by cold air advection and tight pressure gradient with departing low result in the potential for a secondary W wind burst. Models show steep low level lapse rates to H85/H7 which would enable mixing of stronger winds aloft to the surface. Anticipating Wind Advisory event over a portion of southern New England with gusts 40-45 kts. Have issued a Wind Advisory for RI and central/eastern MA for Saturday 10 am to 7 pm. */ Precipitation / Flooding... Could still have some patchy light rain lingering at daybreak, possibly a light snow shower across the highest terrain of Franklin County MA. Looking at model soundings, quite a dry airmass in place but given steep low level lapse rates, can`t rule out an isolated shower or 2, or even a few flurries over the far interior. Otherwise mainly dry day in store. However Flood Watch continues into Saturday, as some area rivers and streams will likely still be rising from the very recent rains. High temps for the day will probably occur in the morning for some locales, especially eastern MA and RI. Temps falling in the afternoon. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Highlights... * Dry/unseasonably chilly Sun into Mon afternoon * Period of heavy rain/renewed flooding concerns late Mon night/Tue with a low risk for a brief period of snow/ice at the onset across the interior * Dry but unseasonably cold Wed/Thu with some moderation by Fri Details... Saturday night... Dry, but breezy to windy weather will continue Sat night in the cold air advection pattern. Bufkit soundings continues to support excellent 25 to 40 mph wind gusts will continue well into the evening. Low temps will bottom out mainly in the middle 20s to the lower 30s...but it will feel colder given the winds. Sunday and Monday... Dry but unseasonably chilly weather will continue Sun into Mon afternoon as high pressure builds in from the west. High temperatures on both days will be only in the 40s. The colder/more breezy day will be Sun and its possible that portions of the interior high terrain does not break 40. Monday night and Tuesday... There continues to be excellent model agreement in an intensifying low pressure system working northward from the mid Atlantic states. The track/timing/strength of this low pressure system remains uncertain given this is 4 days in the future. The lack of downstream blocking or a strong Canadian high pressure system strongly favors a rain event...but a bit of snow/ice can not be ruled out at the onset across the interior. While the system will be progressive...a period of heavy rain is certainly possible with a general 1 to 2 inches of rain. Therefore...we will need to watch for renewed river/stream flooding given some MMEFS projections based on the very wet weather we have had of late. Wednesday through Friday... Deep upper trough setting up across New England will result in dry but unseasonably cold weather Wed into Thu. Low temps mainly be in the upper teens and 20s with highs mainly in the upper 30s to the lower 40s. It will also be quite windy Wed. High pressure will move off the coast Fri...resulting in some moderation in temperatures. Appears mainly dry weather will likely persist. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Saturday/...Moderate to high confidence. Tonight... Widespread low end MVFR-IFR conditions in rain with brief LIFR conditions possible in the heaviest rain. Low risk for an isolated t- storm or two. LLWS expected...but brief burst of strong southerly winds between 35 and 45 knots should be confined to the Cape/Islands in the warm sector later tonight. Worst conditions with respect to winds and LLWS centered 3-9z. Saturday... CIGS improving to VFR or high MVFR to start the day,then clouds scattering out midday-aftn. No VSBY issues. Winds quickly shifting W, then increasing through the day, widespread 35 to 40 kt gusts especially afternoon into evening. KBOS Terminal...Moderate to high confidence. KBDL Terminal...Moderate to high confidence. Outlook /Saturday Night through Wednesday/... Sunday Night through Monday: VFR. Breezy. Monday Night: Mainly VFR, with areas MVFR possible. Breezy. RA. Tuesday: Mainly IFR, with areas MVFR possible. Strong winds with gusts to 45 kt. RA. Tuesday Night: Mainly VFR, with areas MVFR possible. Windy with areas gusts to 30 kt. Chance SHRA. Wednesday through Wednesday Night: VFR. Windy with gusts to 35 kt. Thursday: Windy with local gusts to 30 kt. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Saturday/...High confidence. Tonight... Stout area of low pressure sweeping NE over the Cape Cod Canal shortly after midnight Saturday. S/SE gales forecast with the potential for 45 kt gusts especially near S/SE coastal New England. Wind direction will veer over time as the Gale center tracks over the coastal waters. Wave heights building 9 to 11 feet along the outer coastal waters. Moderate to heavy rain developing during this evening and lasting into early Saturday morning, embedded thunderstorms possible, and likely visibility issues on the waters. Storm force winds possible with heavier rain and/or thunderstorms that may require Special Marine Warnings. Saturday... During early Saturday morning the low pressure lifts NNE into the waters off the coast of Maine. Winds over the S. New England coastal waters are out of the W/WSW for the day. Increasing winds during the day with likely 35 to 45 kt gusts over all waters developing by afternoon and lasting thru the remainder of the day. Outlook /Saturday Night through Wednesday/... Sunday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of seas approaching 5 ft. Monday: Winds less than 25 kt. Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas locally approaching 5 ft. Rain. Tuesday: Moderate risk for gale force winds with gusts up to 45 kt. Rough seas up to 14 ft. Rain. Visibility 1 to 3 nm. Tuesday Night: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 14 ft. Chance of rain showers. Wednesday: Moderate risk for gale force winds with gusts up to 40 kt. Rough seas up to 12 ft. Slight chance of rain showers. Wednesday Night: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas. Thursday: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Local rough seas. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Flood Watch through Saturday afternoon for CTZ004. MA...Wind Advisory until 7 PM EST Saturday for MAZ022>024. Flood Watch through Saturday afternoon for MAZ005>007-012>021. Wind Advisory from 10 AM to 7 PM EST Saturday for MAZ004>007- 012>021-026. Flood Watch until 5 AM EST Saturday for MAZ022. RI...Wind Advisory until 7 PM EST Saturday for RIZ008. Flood Watch through Saturday afternoon for RIZ001>007. Wind Advisory from 10 AM to 7 PM EST Saturday for RIZ001>007. MARINE...Gale Warning until 7 AM EST Sunday for ANZ231>235-237-251. Gale Warning from 10 AM Saturday to 7 AM EST Sunday for ANZ230. Gale Warning until 4 AM EST Sunday for ANZ236. Gale Warning until 9 AM EST Sunday for ANZ250-254>256. && $$ SYNOPSIS...Frank/NMB NEAR TERM...Frank/Sipprell/NMB SHORT TERM...NMB LONG TERM...Frank AVIATION...Frank/Sipprell/NMB MARINE...Frank/Sipprell/NMB
Area Forecast Discussion
National Weather Service Caribou ME
1040 PM EST Fri Nov 9 2018 .SYNOPSIS... Low pressure will approach from the southwest overnight and cross the area Saturday. The low will intensify in the Maritimes Saturday night into Sunday and bring strong winds into the region. && .NEAR TERM /THROUGH SATURDAY/... 1040 PM Update...Adjusted hrly temps to match up w/the latest conditions. Still seeing low to mid 30s across the north while central and downeast areas were seeing upper 30s to lower 4Os. temps will drop off overnight as precip moves in. The latest trend of the regional radar showed reflectivity increasing across the srn and coastal areas w/rain being reported. Further n, llvls still dry given the mid level deck in place. The latest RAP soundings show llvls to moisten quickly w/temps dropping back to AOB 32F leading to snow to develop. Decent mid level forcing advertised by the RAP and 00Z NAM to lead to some heavy snowfall w/snowfall rates 1 to 2 inches per hour. SPC issued a MCD illustrating this potential. Could see a brief period of snow across the Bangor region before a changeover to rain. Speaking of the rain, llvl convergence and forcing will allow for some heavy rainfall across the Downeast region overnight. The current Winter headlines remain in place. Midnight crew may need to expand the Winter Weather Advisory for central areas such as Dover-Foxcroft into Lincoln as cold air could hang in longer allowing for snow to last longer before the changeover. Previous Discussion... The deepening low will track towards the Gulf of Maine and Down East region later overnight into Saturday. This low will actually be close to meeting bombogenesis criteria by Saturday night. This low...and an occluded front stretching back to a low in Canada...will bring a period of heavy precipitation later tonight into Saturday morning. P-type and the rain/snow line is the first challenge for tonight. There antecedent air mass is marginally cold, but evaporative cooling and heavy precip will eradicate the warm boundary layer and create snow...mostly for Piscataquis, northern Penobscot and Aroostook counties. Areas north of a line from Dexter towards the southern border of Aroostook County will receive at least two inches of heavy wet snow. The best coincidence of heavy QPF and cold boundary layer temps appears to be in central Piscataquis County and a Winter Storm Warning has been issued for Zone 10 where towns such as Greenville are at 1000ft elevation. Snow accumulations will be very elevation- driven as it usually the case with early season events. The period of snow will be rather brief with the warm advection, but there is some instability aloft and good omega in the DMZ for several hours. This could produce snowfall rates of 1 to 2 or even 3 inches in an hour. This means poor visibility and quickly deteriorating roads. The late night timeframe will mean that the snow will stick to roads. The warm nose aloft will cause a changeover to sleet after some 3 to 5 hours of moderate to heavy snow. The sleet won`t last more than a couple of hours before precip winds down with arrival of the dry slot and drizzle. The heavy wet snow could cause some power outages. Significant accumulating snow will be over by early Saturday morning and temperatures will exceed the freezing mark and promote melting. Temperatures will actually reach the low to mid 50s in coastal Washington County where the frontal inversion breaks. The warming will be relatively short-lived as a cold front crosses in the afternoon. The front will provide another burst of precipitation...mostly towards northern Aroostook and possibly some wind gusts of 40 to 45 mph as it crosses with some power outages possible. There are some similarities with last Saturday`s cold front with strong winds aloft...upper jet and sharp shortwave trough. Temperatures will fall very quickly behind this front with some icy surfaces possible again by evening. Not a flash freeze...but still a concern. The bombing low pressure and tightening pressure gradient will then start to bring some very strong wind gusts with strong cold air advection and mixing by late day. Towards the coast, there will some heavy rain tonight, but not enough to prompt flooding concerns, outside of some ponding...potentially helped by leaves clogging drains. Strong wind gusts up towards 40 mph are possible late tonight...with momentum transfer from a strong LLJ just offshore. Winds will return late day with the aforementioned cold front. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... By the start of the short term sfc low wl be north of the Gulf of St. Lawrence with wrly winds increasing drg the overnight. Strongest low level winds acrs the area look to be in the 03z-12z Sun timeframe with wind gusts on the order of 30-45kts acrs the highest terrain. This appears to fall strongly in the wind advisory criteria for all areas. Scattered-isold snow showers wl rmn acrs nwrn zones Sat night as upr low pulls into the Canadian Maritimes with nw flow in its wake. Expecting less than an inch of accumulation thru the nighttime hrs. Cold advection with H9 temps dropping to nr -10C by daybreak wl allow temps to dip into the 20s acrs all areas. Highs on Sun wl struggle to rebound into the 30s acrs the north. Skies wl be moclr Sat night and mosunny on Sunday while stratocu still lingers ovr nrn areas into Sun aftn. High pressure builds off the east coast Sun night with ridging relaxing pressure gradient Sun evening. Ridge axis wl bisect CWA Mon aftn. Temps on Mon morning wl start off in the teens in most locations with highs drg the day vry similar to Sunday`s highs, some 10-15 degrees blo normal. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Upr lvl trof dropping into the srn Plains wl induce cyclogenesis acrs the northern Gulf of Mexico on Monday. As this system exits the southeast on Tue morning it wl bring pcpn back into the area late Mon night with stratiform pcpn occurring all day on Tue. Track of the sfc low wl determine ptype with GFS hugging the coast and CMC bringing low thru cntrl portion of CWA on Tue. Euro is the compromise. Hv followed Superblend guidance which appears to be similar to latest Euro and is vry similar to prior fcst. Rain looks to reach as far north as the Caribou area Tue evng bfr colder airmass filters south and gradually switches pcpn back to snow. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: VFR conditions will deteriorate towards IFR to LIFR before midnight at BGR and in the following hours at the remaining TAF sites. Sites such as GNR, MLT and HUL northward will have several hours of VLIFR vis in heavy snow that will definitely affect rwy condition. There may also be a few hours with mixed precip late tonight at BGR. LLWS is expected to be an issue at HUL early Saturday, but could affect other sites too. Snow will be mostly over early Saturday morning except at FVE and the trend will be towards IFR cigs after the snow...until a cold front arrives in the afternoon. The cold front may feature some wind gusts towards 35 or 40 mph. SHORT TERM: IFR expected on Sat aftn all terminals with some improvement to MVFR over Downeast areas by late afternoon. Nrn terminals likely to remain MVFR in stratocu into Sunday then becoming VFR thru Mon night. Gusty west winds expected late Sat night into Sunday morning. Next low pressure system will bring IFR restrictions Tue morning with rain across Downeast and snow across the north. Mixed precipitation moves to the north by Tue afternoon/evening hours. && .MARINE... NEAR TERM: The Gale Warning continues to look solid for tonight. There will be a brief respite in the winds during the morning and they will increase with a vengeance during the afternoon on the backside of the low. These winds will be northwesterly. SHORT TERM: Gales will continue through Sunday, especially on the outer waters. Inner bays will likely relax to strong SCA wind gusts in the afternoon. Seas 5-10 feet into Sun morning in serly swell before dropping blo 5ft Sun night. Wind gusts to remain around SCA levels into Sun mrng before relaxing as high pressure crosses the waters. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 1 PM EST Saturday for MEZ001>006- 031. Winter Storm Warning until 1 PM EST Saturday for MEZ010. MARINE...Gale Warning until 5 PM EST Sunday for ANZ050>052. && $$ Near Term...Hewitt
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
823 PM CST Fri Nov 9 2018 .UPDATE... Overall the short term forecast remains in good shape. I did make a few slight changes to overnight temperatures, which necessitated some slight alterations to the ongoing Freeze Warning. Otherwise, the remainder of the forecast remains unchanged. Dry air continues to filter in across North Texas this evening as surface high pressure slides eastward into the Ozarks. H925 flow should gradually slacken and with dry conditions, boundary layer decoupling should ensue across most of the area---despite the upper level cloud cover. Dewpoints and temperatures were running generally 2-4 degrees below some guidance and the previous forecast. The LAMP and HRRR offer reasonable solutions for hourly and min temperature values. With this in mind, it appears that areas near I-20 may be exposed to a least an hour or two of sub- freezing conditions and I appended a handful of counties to the previous Freeze Warning as a result. Inside the heart of the D/FW Metroplex, temperatures may only near 33-34 degrees, with less urbanized areas of Dallas, Tarrant and Rockwall counties likely falling to 31 to 32 degrees. Regardless, if you have any doubts about protecting sensitive vegetation---it may not be a bad idea to cover them or move them inside. In addition, check on pets and disable automatic sprinkler systems. Outlying areas east of D/FW should also have a decent chance to see temperatures at or below 32 degrees, though far reaches of Van Zandt County may stay closer to 33 degrees as 925mb flow may be a bit brisker due to the slightly tighter height gradient on the periphery of the low level ridge. I added Eastland County, mainly for local effects as low- lying and sheltered regions should easily fall into the low 30s (some sites are already in the upper 30s). There will be a potential for some frost, but overall temperature- dewpoint spreads seem a bit on the marginal side to include in the official forecast. For now, we`ll continue to talk this up in graphics. I also added some silent 10s across Central Texas where some meager ascent continues to overspread the area. The 00 UTC FWD RAOB may have sampled a slightly drier airmass here across North Texas compared to farther south, but it`s unlikely that we`ll see any measurable rain. Still, a sprinkle or two cannot be ruled out near and south of a Comanche to Hillsboro to Athens line. The rest of the forecast is in good shape and updated products and hazards have been shipped. Bain && .AVIATION... /Issued 552 PM CST Fri Nov 9 2018/ 00 UTC TAF Cycle Concerns---None major. VFR with northerly winds becoming easterly through Saturday. VFR will prevail at all North and Central TX terminals through early Sunday morning. Northerly winds will subside tonight with speeds falling to or below 10 knots. There could be some patchy frost on aircraft that remain idle overnight into Saturday morning at area terminals, but the large temperature/dewpoint spread may preclude a more appreciable threat. Northerly winds will become easterly through Saturday morning with a possible return to south flow by the noontime hour on Saturday. High clouds will persist with cigs lowering into the FL070-FL100 range late Saturday evening. Bain && .SHORT TERM... /Issued 350 PM CST Fri Nov 9 2018/ /Through Tonight/ Brisk north winds continue ushering in unseasonably cool/dry air. Even with abundant sunshine, temperatures are only peaking in the low to mid 50s this afternoon, providing a head start for the temperature free fall tonight. Our postfrontal surface high, now centered over Kansas, will drift southeastward toward the Ozarks tonight. Although the core of this arctic air will be far from North Texas, the associated ridge axis will be draped across our northern and western zones tonight. It is in these areas that the winds will subside more quickly this evening, allowing temperatures to fall into the 30s before midnight. (A few wisps of cirrus will do little to disrupt this process.) The 850mb high will settle into our northwest zones during the predawn hours Saturday, the reduction in momentum aloft further enhancing the radiation from the layer beneath it. A more steady breeze through Northeast and North Central Texas (and considerable flow in the 925-850mb layer) will restrain the temperature drop, and the core of the Dallas/Fort Worth Metroplex is unlikely to see freezing temperatures of any significant duration. As a result, a Freeze Warning will exclude the previously watched counties of Tarrant, Dallas, Rockwall, and Kaufman. However, the warning will be expanded in the west to include Stephens. Based on evening trends, Eastland may need to be added as well. For locations in the warned area, November 10 is within a few days of the average first freeze date. There remains some disparity among model guidance with respect to dew points overnight. This is a critical piece of the puzzle as lower dew points will enhance the radiational cooling while reducing the frost potential. Even where the winds are the lightest overnight, calm (or near-calm) conditions may not be prolonged enough to allow ground temperatures to reach their full radiational cooling potential. This will also limit cold air drainage though low-lying and otherwise sheltered areas within the Freeze Warning should still have a greater duration of freezing temperatures. It may be that the greater potential for frost is in areas where the official temperature (several feet above the ground) is actually above freezing, but where the dew points are sub-freezing without being too dry. In other words, even in areas outside of the Freeze Warning, precautions should be taken to protect sensitive vegetation. Assure automatic sprinkler systems are inactive. 25 && .LONG TERM... /Issued 350 PM CST Fri Nov 9 2018/ /Saturday Through Friday/ The upper pattern will remain active through early next week with a few chances for rainfall, our first arctic intrusion into the region, and at least a brief shot for some wintry precipitation across the northwest. Saturday will start off cold with many areas north of the Metroplex to the Red River near or a few degrees below freezing under mostly clear skies. Changes will be quick to occur though as the surface high slides into the mid-Mississippi River Valley and low-level flow begins to veer to the south. Strong mid-level isentropic ascent will overspread the area from southwest to northeast starting around midday and continuing into the evening. We`ll see a rapid increase in mid-level cloud cover through the day Saturday, although we should remain mostly precipitation free. Despite the strong ascent, the layer beneath 700 mb will remain quite dry. It`s always a little concerning when mid level moisture becomes available within an area of lift. This can often result in high based showers or storms in the presence of instability. With the strongest lift quickly moving to the northeast into Saturday evening, we`ll keep PoPs at 10% through the day. Saturday night should be rain free, although overcast conditions will prevail with our moisture depth increasing under the influence of persistent southerly flow. Temperatures will be about 5-10 degrees warmer Saturday night across the region. The upper pattern will also begin to amplify during this time with a strong shortwave trough digging into the western U.S. On Sunday, with the upper trough over the 4-corners region, cold air will begin to spill southward through the Plains and into Texas during the afternoon. Strong low-level warm advection will likely result in an area of showers and perhaps a few thunderstorms mainly east of I-35 into the evening hours. This initial wave of ascent should spread off to the northeast into the late evening hours and we may actually see a decrease in the coverage of precipitation prior to midnight. After midnight, much stronger forcing for ascent associated with the approaching upper trough will begin to spread through the Southern Plains. Coverage of rain should increase areawide late Sunday night into Monday morning. Isentropic ascent should be maximized across North Texas very late Sunday night into early Monday morning. A deep column of saturated air located within this area of ascent and a favorable upper jet position should support several hours of moderate precipitation across the region through mid-morning Monday. Surface temperatures during this time will likely be in the upper 30s and the prevailing precipitation type will be all rain. There will be a brief period very early Monday morning where column temperatures cool sufficiently, and we retain deep moisture for snow production to occur. This is most likely to happen northwest of the Metroplex from Gainesville to Mineral Wells to Eastland where we`ll introduce a slight chance of snow mixed with rain. Upstream dry air will quickly spread into the region from the northwest by late morning effectively ending any wintry precipitation potential through the rest of the day. Given the limited time duration in which snowfall could occur, and well above freezing surface temps, no significant impacts are expected. Precipitation will quickly end from west to east during the day Monday with highs likely remaining in the upper 30s and lower 40s. Dry north-northwest flow aloft will prevail through the end of next week with temperatures warming back into the 60s by Thursday. Dunn && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 32 51 42 51 41 / 0 5 10 30 60 Waco 36 52 43 52 44 / 10 10 10 50 60 Paris 29 48 39 47 40 / 0 5 10 20 70 Denton 31 51 41 51 41 / 0 5 10 20 50 McKinney 30 49 41 49 41 / 0 5 10 20 60 Dallas 32 51 43 51 42 / 0 5 10 30 60 Terrell 32 52 42 50 42 / 0 10 10 40 70 Corsicana 35 51 43 51 43 / 10 10 10 50 70 Temple 38 51 44 52 45 / 10 10 10 50 60 Mineral Wells 31 51 39 53 38 / 0 5 10 20 60 && .FWD WATCHES/WARNINGS/ADVISORIES... Freeze Warning from 3 AM to 9 AM CST Saturday for TXZ091>095- 100>107-115>123-129. && $$ 24/08
National Weather Service Jackson KY
1001 PM EST Fri Nov 9 2018 .UPDATE... Issued at 1000 PM EST FRI NOV 9 2018 Colder air continues to advect into the region, most noticeable still on the highest ridges. Loaded in the latest observations for temps and winds to make sure the near term forecast reflected the ongoing conditions. NW flow is also keeping drizzle across portions of the CWA, but with a shot of colder air moving into the western CWA now, not surprised if some of this rain is starting to change over to or mix in with some snow flurries. A new set of zones was sent out to reflect overnight wording and any updates to the weather as light precip continues to change over before tapering off late tonight. UPDATE Issued at 729 PM EST FRI NOV 9 2018 Rain has now exited east of the CWA with residual upslope flow and drizzle taking hold across portions of the CWA. With the slightly quicker exit of the precip, and the breezy NW flow, temperatures are starting to drop, especially over the higher terrain. Based on latest observations, higher terrain is trending down faster than the original forecast, and will likely fall below the forecasted low temperatures if this rate continues. Went ahead and adjusted the temperatures during the current hour to match the ongoing observations, then proceeded to update the hourly temps throughout the night to show a better diurnal trend of falling temps. Also updated the forecasted lows and highs for tomorrow as well. Finally, adjusted pops to better reflect the current trends, with a quicker exit of rain showers now east of the region. Reran the weather grids based on the updated pops and temps. All updates have been published and sent to NDFD/web. A new forecast package will be sent out shortly as well. && .SHORT TERM...(This evening through Saturday night) Issued at 325 PM EST FRI NOV 9 2018 19z sfc analysis shows low pressure pulling further away from the area to the northeast. The system`s cold front is now east of the state allowing west to northwest winds to pick up to between 5 and 10 mph this afternoon across the CWA. Temperatures are struggling to rebound much today in the face of this cold air advection. Accordingly, readings range from the lower 40s in the northwest to the mid 40s in the southeast. Dewpoints are just a couple of degrees below dry bulb temperatures most places. The main area of rain showers is slowly progressing east on radar with a back edge currently from West Liberty southwest to near London. Likely some light rain or drizzle follows this rain under overcast skies. Some patchy fog remains around accompanying the rain - mainly on the eastern ridges. The models are in pretty good agreement through the short term portion of the forecast. They all depict the bottoming out of a fairly deep trough over the Great Lakes tonight with troughing passing through the Ohio Valley along with a 300mb jet streak. This feature then lifts out of the area on Saturday relaxing the lower heights over Kentucky but maintaining the fairly fast flow in its wake along with ample amounts of energy through midday. This mid level flow becomes southwesterly later Saturday into Sunday morning with weaker energy packets running overhead during this time. Given the model agreement have favored a general blend with a strong lean toward the HRRR and NAM12 for details. Sensible weather will feature the bulk of the rain exiting by early evening though a few pockets of sprinkles and light rain will trail behind. Colder air will keep getting pulled into the area on northwest winds through the evening and overnight so that any lingering showers could transition to snow showers from west to east through the middle part of the night. The 5h trough digging past to the north will likely enhance these showers a bit despite an overall drying trend - along with the upslope flow - to maintain the snow shower threat into dawn for the eastern portion of the state. Still believe that the warm ground temperatures will limit any dustings to elevated surfaces and on the grass into Saturday morning. Further drying will likely cut off any lingering snow showers and flurries by mid morning. One small concern during this transition time will be the potential to lose ice crystal formation for a time during the early morning hours that could lead to pockets of freezing sprinkles or drizzle - but most places will be able to go over to scattered snow showers without any freezing pcpn. Will limit the mention of this possibility to the HWO for now and allow subsequent shifts evaluate the potential for limited icing and/or a dusting of snow in the far east. Some sunshine returns by Saturday afternoon, though temperatures will be hard pressed to climb out of the 30s with light northwest winds adding to the chill. Clear skies and high pressure passing through on Saturday night will set up a very cold night with some readings in the upper teens possible for sheltered valleys by dawn. Used the CONSShort and ShortBlend model guidance as a starting point for all the grids. Adjusted temperatures Saturday night to add in more of ridge to valley split through dawn Sunday. As for PoPs did linger them longer for the higher terrain in the far east through the night and into Saturday morning. Did also minimize the freezing rain potential by increasing the ProbIce grids to near 100 percent late tonight. .LONG TERM...(Sunday through Friday) Issued at 250 PM EST FRI NOV 9 2018 The extended period will feature a period of wet and active weather sandwiched by periods of quiet and dry weather across eastern Kentucky. The period should start off dry, albeit still much cooler than normal, on Sunday, as a ridge of high pressure remains entrenched across the region. The ridge will eventually begin to break down and move off to our east late Sunday night into early Monday morning, as a strong area of low pressure begins to invade the region from the south. The latest model data continues to support this scenario. This area of low pressure is forecast to move across the Gulf Coast region and eventually across the southeastern CONUS and then up the east coast Monday and Tuesday. This system will bring a combo of rain and snow to eastern Kentucky Monday night and Tuesday. The latest model data is suggesting the possibility of light snow accumulations Monday night into Tuesday morning, especially along and west of a line from Inez to Jackson to Williamsburg. Their continues to some differences amongst the various models regarding timing of the weather system across the area, precipitation onset, and duration of any snow fall. The general trends that are being observed at this time are for the snow to penetrate a bit further east into the forecast due to cold air progressing a bit further south and east than previously thought. However, due to the amount of uncertainty that still exists in the models, we will continue to take this situation with a grain of salt, at least until the models hone in more on a common solution. This weather system is currently being forecast to exit the area, along with all its precipitation early Tuesday night. A large area of high pressure is then forecast to settle over the region on Wednesday, and may remain in place through the end of the week. Should the model data prove correct, this will be the coldest air we will have seen across eastern Kentucky so far this season. Temperatures will continue to run well below normal during the period, with daily highs in the 30s, 40s, and 50s expected. Nightly lows will run from the upper teens to the mid 30s. The coldest period will be the Tuesday through Thursday time frame. Highs on Tuesday are expected to range from the upper 30s to lower 40s, with lows on Wednesday likely not making it out of the 30s for most locations. After the area of low pressure finally exits the area Tuesday night, a strong ridge of high pressure will usher in the coldest air of the season for the middle of the week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 738 PM EST FRI NOV 9 2018 The surface cold front that impacted the region today has now moved east, with high pressure moving in from the west. Moist llvls and northwest flow is now leading to drizzle across portions of the region, with some of the highest peaks across eastern KY possibly seeing a changeover to flurries as temps fall below freezing. VIS has improved to VFR with the exit of the rainfall, and CIGS are continuing to improve as well, generally between MVFR and VFR. Continued cloud cover and breezy winds will likely prevent fog formation overnight. Expect CIGS to continue lifting and improving throughout the overnight, with mostly clear skies expected during the day Saturday as the are of high pressure moves across the state. Winds will also become light and variable during the day tomorrow as a result. .JKL WATCHES/WARNINGS/ADVISORIES... && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...GREIF LONG TERM...AR AVIATION...JMW
Area Forecast Discussion
National Weather Service Paducah KY
800 PM CST Fri Nov 9 2018 .UPDATE... Issued at 800 PM CST Fri Nov 9 2018 A low-topped line of snow squalls continues to march southeast of the St. Louis metro area this evening. There has even been some thunder observed in the squalls, which reduced vsby to 1/4 mile in a few spots. A narrow but well-defined trough of low pressure accompanies this line, followed by a few hours of strong northwest winds gusting up to 35 to 40 mph. The driving force for the snow squalls appears to be steep low-level lapse rates along the arctic cold front. Model soundings from the rap indicate lapse rates will slowly weaken ahead of the front. The line will also be moving into slightly drier air. There are already some indications the line is decreasing in width. The current forecast appears to have these trends covered well. A brief burst of heavy snow is likely in the advisory area this evening. The main impacts will be from low visibility and gusty winds, as opposed to hazardous road conditions. There will be some slick spots, mainly on bridges and overpasses. Little if any snow shower activity is expected in southwest Kentucky, where drier and more stable air will be hostile to the convective snow showers. && .SHORT TERM...(Tonight through Sunday night) Issued at 308 PM CST Fri Nov 9 2018 Transition to an winter weather advisory event made this afternoon for a few counties along Interstate 64 in southern Illinois. In previous forecasts have hinted at a rain/snow to snow mix in southern Illinois and southwest Indiana, but refining the timing and placement of mesoscale wintry system has not been attainable until now. The main challenge with the system has been the degree of intrusion of drier air from the southwest, limiting the effective coverage of ice nucleation in the preferred snow growth layer. However, the sharp intensification of the closed low over Wisconsin, the deepening of the baroclinic zone (channeled vorticity arcing down through central Illinois between 21z (3 pm) and 03z (9 pm)) should support more significant lift, compensating for the less than ideal moisture. With emphasis toward the RAP numerical guidance as a proxy for other high resolution guidance, the northern end of the WFO PAH forecast area (Interstate 64 corridor) will slowly move away from the favored right exit region (corridor of 125-130 knot winds) of the 300 mb jet axis, but the proximity of another jet max further south may still sustain broad lift into southwest Indiana and northwest Kentucky. Maximum wet bulb through the 0-6km layer rapidly move from zero to minus 3 degrees Celsius during the evening hours, while the surface wet bulb temperatures drop into the 30-31 degree range in advisory area. Upper level divergence is maximized over southeast Illinois and southwest Indiana between 02z-05z this evening. The I-64 corridor is on the very edge of the greatest vertical motion in the snow growth layer. At the surface, there will be a tight pressure gradient between the high pressure surface in eastern Kansas and the surface low in in the upper peninsula of Michigan. This pressure gradient, combined with vertical mixing with the quick moving system tonight, will generate wind gusts averaging around 25 mph over southern Illinois, southwest Indiana, and northwest Kentucky. This may cause issues for travelers tonight and help to accelerate transfer of colder air into the region. At this point in time, concerned that snowfall rates may exceed the ability for ground and road surfaces to melt adequately for an hour or less in the advisory area. This may also reduce visibilities over short distances, creating hazardous travel conditions in the advisory area this evening. An winter weather advisory was issued for the area expecting the most impact, then surrounded with a Special Weather Statement for adjacent counties south and east of the advisory area that may see lesser impact this evening. Recent numerical model trends continue to support low to middle 20s for lows tonight and Saturday night, with highs mainly in the 30s on Saturday. There is expected to be a slight recovery in temperature on Sunday into the 40s, before the next system moves into the area early next week. Leaned closer to the Canadian (CMC) and NAM-WRF (ARW version) for dewpoints through this weekend, blended with short term model blends. Utilized the NAM-WRF, NAMNest, RAP, and ESRL HRRR guidance for the timing of this evening`s system, temperature, and wind trends. .LONG TERM...(Monday through Friday) Issued at 308 PM CST Fri Nov 9 2018 Potential impact storm at start of period, with big system still taking shape in southern Plains but moisture plume working its way across lower Mississippi river valley, and northern extent of moisture is possibly working into our (mainly southern) counties at 12Z Monday. This will cause a pre-event potential for wintry pcpn type, bc sfc temps at that time will be 30-35F. A closer inspection of sounding data shows a pretty dry layer below 850 mb though, so any pcpn actually reaching the ground should be very light until later in the day, when temps will be warm enough to support all liquid. As the long wave trof digs/sharpens upon its ejection across the lower Mississippi river valley Monday evening, it develops a surface Low along the Gulf coast, which lifts northeast across the Deep South. The cold air that drags down overtop the PAH FA, will work the profile/enable the overrunning moisture to turn from liquid to frozen during the overnight hours. The question is, how much of that moisture will be overrunning that far north, for appreciable pcpn. The 12Z blended modeling/forecast builder now is producing light amounts from a half inch to potentially an inch across portions of our south and our east. Confidence remains low for overall accumulating/significant snow, particularly given ground temps, but is growing that some changeover snow will occur. Even a light event, with Tuesday daybreak temps in the 20s, could cause some impacts Monday night-early Tuesday morning, so it`ll be something to watch closely as we draw nearer in time. The 12Z Euro just in...looking more like the 12Z GFS...if that pans out, light qpf of .1 to .2 across esp western Ky could produce a light snowfall event for mainly Monday evening, into the overnight. Something to keep tabs on further but will start to hit on it in the HWO update. The blend is now quicker ending the pcpn by 12Z Tuesday, so it is almost exclusively a (Monday-)Monday night event. The blend is also colder with the post system cold advection, keeping Tuesday Highs in the 30s and producing some teens for Lows Tuesday night. While a drying and moderating temperature trend is called for Wednesday-Friday, it will remain below seasonal norms. && .AVIATION... Issued at 509 PM CST Fri Nov 9 2018 Areas of MVFR cigs will continue this evening along with a few light rain or snow showers mainly across southern IL into southwest IN. Prob`s too low to include in the TAF`s. Overnight into Saturday, mainly clear. Gusty northwest winds this evening will diminish late tonight, and switch gradually to the north, and then east Saturday. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Winter Weather Advisory until 10 PM CST this evening for ILZ075>077. MO...None. IN...None. KY...None. && $$ UPDATE...MY SHORT TERM...Smith LONG TERM...DH
Area Forecast Discussion
National Weather Service Sacramento CA
322 PM PST Fri Nov 9 2018 .SYNOPSIS... Dry with warmer than normal temperatures through next week. Critical fire weather conditions return Saturday night through Monday morning. Widespread smoke from the Camp Fire will continue. && .DISCUSSION... Latest satellite imagery indicates smoke and haze impacting interior NorCal as the Camp Fire continues to burn. Current afternoon temperatures, except for the N Sac Valley, are running several degrees cooler compared to yesterday`s given areas of smoke. Pressure gradient has trended downward, and winds have decreased across the region. An upper disturbance will dig into the Great Basin Saturday night into Sunday tightening N-S pressure gradient in the Central Valley and SW-NE gradient over the eastern foothills and mountains. Although these winds may not be as strong as Wednesday night and Thursday, the combination of gusty winds and lowering humidity will lead to critical fire weather conditions Saturday evening into Monday morning. Thus, a Red Flag Warning is in effect for most of interior NorCal. Winds will remain gusty over the eastern foothills/mountains through Monday morning. Then, lighter winds are expected Monday afternoon as surface pressure gradients relax. HRRR smoke model shows smoke continuing to spread across the entire Central Valley today, and persisting into tomorrow. Smoke will make for a tricky forecast the next few days, especially in areas where the smoke is thick. Poor air quality can be expected, so make sure to check on sensitive groups. Dry conditions will prevail across interior NorCal as high pressure remains in control. High temperatures will continue to run about 5 to 10 degrees above normal. Look for Valley highs in the 70s, and 50s/60s over the mountains. Overnight lows expected in the mid 30s to low 40s across the Valley. && .EXTENDED DISCUSSION (Tuesday THROUGH Friday) High amplitude ridge with axis over the west coast will keep the CWA under warm and very dry conditions Tuesday but winds should be relatively light. Slightly warmer conditions are expected Wednesday through Friday with daytime highs running 5 to 10 degrees above normal. Fair skies over night will allow minimums to drop to a little below normal. No strong wind events are expected through the extended period although models indicate a brief period of increased ridge winds on Wednesday in the wake of a weak system passage to the north. && .AVIATION... Smoke from Butte County wildfire drifting Swd with areas of MVFR ceilings and visibilities over TAF sites. Local IFR conditions may occur briefly at times overnite. Smoke layer most likely will not mix out due to light winds and limited mixing height on Sat. Gusty north to east winds forecast to redevelop Sat nite into Sun with gusts 40-50 kts possible over higher terrain and gusts 30 kts on west side of Sac Vly. Winds decrease Sun nite and Mon. && .STO WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 10 PM Saturday to 7 AM PST Monday for Burney Basin and Northeast Plateau in Shasta County Including Northwest Lassen NF north of Lassen NP-Carquinez Strait and Delta-Central Sacramento Valley in Glenn, Colusa, Yuba, Northern Sutter, and Butte County Below 1000 Ft-Eastern Mendocino NF- Eastern Portion of Shasta/Trinity NF-Lake County Portion of Lake- Napa-Sonoma Unit-Northern Motherlode From 1000 to 3000 Ft. Includes portions of Nevada-Yuba-Placer-Amador and ElDorado Units-Northern Sacramento Valley to Southern Tehama County Line Below 1000 Ft-Northern Sierra Foothills from 1000 to 3000 Ft. Includes portions of Shasta-Trinity and Butte Units-Northern Sierra Including Lassen NP and Plumas and Lassen NF/S West of the Sierra Crest (West of Evans Peak-Grizzly Peak-Beckworth Peak)-Northern Sierra Including the Tahoe and ElDorado NF/S West of the Sierra Crest-Southeast Edge Shasta-Trinity NF and Western Portions of Tehama-Glenn Unit-Southern Motherlode From 1000 to 3000 Ft. Includes portions of Calaveras-Tuolumne Unit-Southern Sacramento Valley in Yolo-Sacramento Far Western Placer, southern Sutter and Solano County Below 1000 Ft-Stanislaus NF West of the Sierra Crest. && $$