Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/04/18

Area Forecast Discussion
National Weather Service Grand Rapids MI
628 PM EST Mon Dec 3 2018 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 251 PM EST Mon Dec 3 2018 Fairly quiet weather this week with cold temperatures and only light snow chances for Wednesday through Friday. && .DISCUSSION...(This evening through next Monday) Issued at 251 PM EST Mon Dec 3 2018 Fair weather overnight then some snow showers possible across the western zones on Tuesday as northerly flow tonight becomes northwest then west. Inversion heights are around 5 kft and this will keep any accums light. Lake enhanced snow showers get a boost on Thursday with clipper and arctic front providing low level convergence as inversion heights come up a bit. Expect an inch or two with this event and possibly another inch or two over the course of westerly flow lake effect snow showers Thursday night and Saturday.&& .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1252 PM EST Mon Dec 3 2018 Ceilings will be in the 1500 to 2500 foot AGL level this afternoon with tops above 5000 feet decreasing to about 3000 feet by late afternoon. VFR conditions are expected this evening and into Tuesday. Lake effect snow showers should remain over Lake Michigan in northerly wind regime. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 629 PM EST Mon Dec 3 2018 For the most part expect MVFR cigs through Tuesday night. Also expect in cloud light to moderate rime icing between 2500ft agl and about 6000 ft agl. during this time period. It should be noted however I do expect a short period of clearing late tonight into the mid morning hours of Tuesday thanks to the prevailing north wind bringing down drier air from the north. Even as I write this the clearing line is moving south into northern Lower Michigan from eastern Upper Michigan. This clearing is shown in both the NAM and RAP models in the 09z to 15z time frame. The RAP model is stronger in the clearing and if that turns out to be correct the clearing may last most of the day for the TAF sites east of Grand Rapids. && .MARINE... Issued at 251 PM EST Mon Dec 3 2018 No changes to the Small Craft Advisory. && .HYDROLOGY... Issued at 1252 PM EST Mon Dec 3 2018 Water levels in the larger rivers and streams continue to rise in response to rain and snowmelt over the weekend. Rivers and streams in the eastern portion of the Grand River Basin will rise to bankfull or near-bankfull through the end of the week, but will not reach flood stage. Precipitation through the rest of the week will be in the form of occasional light snow and will not have any impact on river levels. Temperatures will be below freezing through most of the next seven days. While ice may form on some creeks and streams, freeze-up ice jams are not anticipated. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...Small Craft Advisory until 3 AM EST Tuesday for LMZ844>849. && $$ SYNOPSIS...Ostuno DISCUSSION...Ostuno AVIATION...WDM HYDROLOGY...HLO MARINE...Ostuno
National Weather Service Jackson KY
1101 PM EST Mon Dec 3 2018 .UPDATE... Issued at 1101 PM EST MON DEC 3 2018 Isolated to scattered showers, likely falling as snow above about 2000 feet, and rain or a rain and snow mix elsewhere continue across the area. Based on regional observations from the KY Mesonet, AWOS, and KYTC stations, temperatures remain above freezing below 2500 feet. With this and upstream temperatures mainly in the low to mid 30s, it appears that valleys across southeastern portions of the area will probably not quite reach the freezing mark overnight. Isolated to scattered upslope/instability snow showers are anticipated at times overnight. UPDATE Issued at 725 PM EST MON DEC 3 2018 An area of showers continues to move across East KY this evening. This has mostly fallen as rain with surface wetbulb temperatures generally above freezing, around the mid 30s. The highest terrain has cooled off sufficiently enough that this precipitation will fall as snow on top of Black and Pine Mountains. Even there, temperatures are not below freezing below 3000 feet. Hourly pops and temperatures were adjusted to account for recent radar and observation trends. Overall, no substantial changes were needed at this time. && .SHORT TERM...(This evening through Tuesday night) Issued at 345 PM EST MON DEC 3 2018 20z sfc analysis shows a large area of low pressure off to the northeast of Kentucky with cyclonic flow through the Ohio Valley. This flow continues to bring in lower level clouds over eastern Kentucky and points northwest. This, along with some cold air advection on westerly winds at 5 to 10 mph (with occasional higher gusts), has lowered temperatures through much of the afternoon. Readings now vary from the upper 30s northwest to the mid 40s in the far southeast or several degrees down from noon readings most places. Dewpoints, meanwhile are generally running in the lower 30s. Some light returns are showing up on radar with reports of light rain reaching the ground north, though some flurries could be mixing in as the boundary layer temperatures are falling through the upper 30s in the northwest parts of the area. The models are in good agreement aloft through the short term portion of the forecast. They all depict some weak waves running along the base of a large trough through the heart of North America in nearly zonal flow. The first of these pass through this evening with another stronger one due in here later Tuesday through Wednesday morning. The model agreement raises confidence for the weather details through Wednesday morning even as it falls later in the forecast with widening model spread. Through the short term have favored a general model blend with a strong lean toward the higher resolution near term models like the HRRR and NAM12 for details. Sensible weather will feature a chilly couple of days as clouds and a cooler air mass have settled over the area. With this, there will be periodic bouts of light pcpn mainly in the form of light rain/sprinkles this evening and snow showers/flurries later tonight through Wednesday morning. Given the warm ground and road temperatures any snow shower activity through the day Tuesday will not accumulate except perhaps a thin layer on elevated or grassy surfaces. A better chance for some light snow to stick to the ground will be Tuesday night into Wednesday morning when up to an inch could occur on the ridges in the east with lesser amounts seen elsewhere. Temperatures will not exhibit much of a diurnal range during this time with highs only in the the mid 30s most places Tuesday but lows that night down to the mid and upper 20s. The accumulating snow chances late in the period will be highlighted in the HWO along with a forthcoming partner email addressing the winter weather threat through Wednesday morning. Used the ShortBlend and CONSShort again as the starting point of the grids, though did tweak some point temperatures for very minor terrain aspects both nights. As for PoPs: adjusted them slightly per the near term guidance for better snow chances, especially Tuesday night. .LONG TERM...(Wednesday through Monday) Issued at 305 PM EST MON DEC 3 2018 The forecast issues in the extended will center around the potential for wintry precipitation at different time through out the period. Initially, we can expect isolated to scattered snow showers across the area on Wednesday, as moist westerly flow behind a departing area of low pressure interacts with the terrain of eastern Kentucky. Snow fall amounts during this time should be very light, but it will remain to be scene whether or not any impacts will result from this initial snowfall. After a dry period Wednesday night through Thursday morning, another round of rain and snow is expected. This second round of precipitation is a bit more uncertain, as the latest model runs are having a difficult time producing much in the way of moisture across the region. Based on that, decided to decrease precipitation chances for the time frame from Thursday afternoon through Friday morning. Another brief lull in the action is expected for most of the day on Friday. The biggest player in the extended period will be a weather system that is forecast form somewhere along the western Gulf coast Friday night into Saturday morning. The forecast are very different from one another regarding the exact track and timing of this third weather system. One model is taking the low track along the Gulf Coast, which would keep precipitation associated with the system well south of eastern Kentucky. Another model has the system tracking a bit further north, but still far enough south to keep most are all precip outside of our area. Two other weather forecast models have the system tracking far enough north to bring rain and then decent snowfall into eastern Kentucky Saturday into Sunday. The issue here is that each of these models have different timing with precip onset and evolution of the system as it moves off to the east. At this time, with all the uncertainty involved, the blended model data was used to create the forecast for the extended. The trend in the blended data was for lower precipitation chances across the area, likely due to the uncertainty contained in the individual models. In general, the best chance for precipitation should be for the weekend. Snowfall amounts should be taken with a grain of salt until the individual models come into better agreement. Temperatures during the extended look to be well below normal, with daily highs forecast to max out generally in the 30s to mid 40s, and nightly lows in the low to mid 20s. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 720 PM EST MON DEC 3 2018 A cloud deck with mainly VFR currently reported across East KY with some patches of MVFR. With continued cooling and saturation of the atmosphere closer to the surface, ceilings should gradually decrease into the MVFR range in all locations over the first 6 to 9 hours of the period. MVFR should persist through at least 18Z all locations, though some patchy VFR is possible late in the period. West to northwest winds of 5 to 10 kts ushering in colder air initial isolated to scattered rain or snow showers are expected with any remaining precipitation mainly isolated to possibly scattered snow showers after 6Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...JP
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
950 PM CST Mon Dec 3 2018 .UPDATE... Minor update to add the mention of fog across the southwest/south-central Texas Panhandle into the northern South Plains late this evening, expanding to all areas on the Caprock after midnight. Temperatures have cooled efficiently this evening and were now approaching the dewpoint across the northwestern zones. Hereford was already reporting light visibility reductions, and the webcam at Silverton was showing a hazy view...perhaps the precursor of thicker fog to come. The HRRR and RAP are now suggesting at least patchy fog (locally dense) will form over parts of the Caprock through the night as the weak, cool and moist upslope flow continues. Winds will veer toward morning, and this could limit the extent of the fog. Any fog should lift/scatter by mid-morning Tuesday. No other adjustments were made to the forecast at this point. && .PREV DISCUSSION... /issued 602 PM CST Mon Dec 3 2018/ AVIATION... VFR has returned to all three TAF sites and should persist this evening. It becomes less clear late tonight into Tuesday morning as cool and relatively moist conditions linger. Our guidance varies greatly, showing anything from VFR to IFR developing at all three TAF sites. Thus, confidence in outcome and timing is low, but have continued to reflect MVFR conditions at the terminals late tonight, lifting to VFR Tuesday afternoon. Winds will be light through the period. PREV DISCUSSION... /issued 424 PM CST Mon Dec 3 2018/ DISCUSSION... Surface high pressure currently centered over the north Central Plains and northwest flow aloft will continue the cooler than normal temperatures through mid-week. The cooler temperatures will persist out ahead of a developing upper level, closed low that will bring rain on Thursday and a wintry mix of precipitation on Friday into Saturday. The Pacific low will shave the coast of California over the next couple of days and then evolve into an open wave, becoming more progressive as the southern jet becomes more active. Rain on Thursday should mostly be relegated to the southern half of the South Plains and Rolling Plains ahead of a surging cold front. The front will move south out of the Texas Panhandle during the day Thursday, with a moisture gradient that extends from central Texas westward along the I20 corridor. As the surface low begins to deepen late Thursday night while it moves out of West Texas over central Texas, colder air from the aforementioned surface front will be reinforced on the back side of the exiting low. A wintry mix may begin to develop overnight Thursday into Friday across our northern zones before sunrise. Current vertical profiles hint at some freezing rain overnight, but its too soon to have confidence in that outcome. From that point on there remains quite a bit of uncertainty with regard to precipitation phase through the day on Friday. Best chances for wintry precipitation during the day Friday will be across the southern Texas Panhandle with more of a mix of rain/sleet/snow possible over the South Plains and Rolling Plains. Whatever moisture remains into late Friday and early Saturday should result in light snowfall. Overall, impacts should be minimal, though travelling across our forecast area during the day on Friday may get increasingly more difficult the farther north you go. We dry out quickly on Sunday with temperatures returning to the mid 40s as an amplified ridge builds over the west. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 23/99
Area Forecast Discussion
National Weather Service Marquette MI
536 PM EST Mon Dec 3 2018 .SHORT TERM...(This evening through Tuesday) Issued at 335 PM EST MON DEC 3 2018 WV imagery and RAP analysis indicated mid/upper level ridging from the northern plains and upper Mississippi valley building into the northern Great Lakes. At the surface, high pressure was also building into the area with increasingly anticyclonic nw to n flow. With subsidence and drier air moving in from the north, some holes have developed over the cloud deck with clearing on upstream shores of Lake Superior. With 850 mb temps only to around -9C and relatively shallow moisture, any flurries or freezing drizzle has ended. Tonight, winds will back west-northwest tonight as the high pressure ridge moves across the area. The backing winds will focus any LES that develops over the nw and from Marquette eastward as partial clearing will be possible over central and southern portions of Upper Michigan. Some fzdz may still be possible with only marginal temp/moisture profile for ice nuclei availability. However, given the amount of low level drying, expect little potential for any significant glaze. Tuesday, winds will back to w or wnw limiting light LES/flurries to the Keweenaw and locations north of M28 over the east. The low level west winds will favor at least partial clearing over the rest of the area. Highs will remain in the mid to upper 20s. .LONG TERM...(Tuesday night through Monday) Issued at 324 PM EST MON DEC 3 2018 Tranquil through midweek followed by a brief uptick in northwest wind lake effect with a return to quiet seasonable weather over the weekend. Mean upper troughing will remain over the eastern U.S. into the weekend. A clipper system and associated cold front will usher a brief surge of below normal temperatures into the Upper Lakes for Thursday and Friday. The arrival of this colder airmass with 85H temperatures lowering to -20C will briefly spike lake EL levels up close to 10kft late Wednesday night into early Thursday. This will be the time period for a burst of moderate snow for northwest wind favored areas with a few inches of accumulation. Prior to the arrival of this front 85H temperatures will be marginal for some light westerly wind lake effect across the Keweenaw on Wednesday. Accumulations will be very light. Inversion heights begin to lower significantly by later Thursday into Friday. 85H temperatures will support continuation of northwesterly wind lake effect, but amounts will remain in check. By Saturday...upper heights begin to rise across the Plains with west northwesterly wind warm advection bringing an end to the lake effect. Temperatures will modify back to normal with dry weather for the weekend into early next week. Push of mild Pacific air in a more zonal pattern will result in a mild middle part of December with above average temperatures and limited significant storm chances. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 536 PM EST MON DEC 3 2018 Low end MVFR Cigs will persist through tonight with low level moisture lingering below a strengthening inversion. Marginal improvement is expected at KSAW with climbing CIGS that may scatter out by Tuesday afternoon as drier air moves in with winds backing wrly. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 335 PM EST MON DEC 3 2018 As the pressure gradient continues to weaken north winds will diminish to 20 knots or less tonight into Tuesday morning. while backing west-northwest. Tuesday afternoon into Wednesday westerly winds will increase slightly to 15 to 25 knots. Next chance for stronger northerly winds will arrive late Wed night into Thursday behind a stronger cold front when northwest to north gale force gusts are possible && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...MZ AVIATION...07 MARINE...JLB
Area Forecast Discussion
National Weather Service Tallahassee FL
843 PM EST Mon Dec 3 2018 .UPDATE... The main changes to the forecast involved the departure of precipitation from the region and some fog development this evening. Regional Radars indicate the axis of showers has shifted just south of Dixie County and the coastal waters. The high resolution guidance such as the HRRR has a good handle on this activity, which may occasionally shift into the far southern Coastal Waters and Dixie County through around midnight, where there is a chance of showers. Dry thereafter. Clear skies have developed as of late this evening from the Western Panhandle into Southwest Georgia between low clouds across the southeast Big Bend and mid to high clouds over Southeast Alabama. Under the clear skies, a saturated near-surface layer and light winds is promoting the development of some patchy fog already! This should be short lived however, as the boundary layer wind increases tonight and drier air advects into the area. Nonetheless, cannot rule out some patchy dense fog, mainly north of Interstate 10 and east of the Chatahoochee River. && .AVIATION... [Through 00Z Wednesday] VFR through the TAF period with the exception of ABY and VLD where MVFR in BR is possible tonight. Northwest winds will be around 5 kt or less tonight, becoming northerly on Tuesday 5 to 10 kt with gusts up to around 15 kt. && .PREV DISCUSSION [631 PM EST]... .NEAR TERM [Through Tonight]... Rainfall tapering off quickly tonight as the cold front exits the forecast area to the south and east. Showers will linger a bit longer in the SE big bend area, although all areas will eventually clear out with only some periodic high clouds for the remainder of tonight. Expect lows in the low to mid 40s for most of the forecast area, and in the lower 50s for the SE Big bend. .SHORT TERM [Tuesday Through Wednesday Night]... Surface high pressure builds in from the west bringing with it a cooler and much drier airmass. The coldest temperatures will be Wednesday/Wednesday night with the surface high settling over the southeast CONUS. Highs will be in the 60s Tuesday and only 50s on Wednesday. Lows will be in the mid 30s to around 40 Tuesday night with a widespread light freeze likely Wednesday night across inland areas. .LONG TERM [Thursday Through Monday]... Surface high pressure will continue to move east and weaken through Friday making way for a vigorous southern stream low pressure system that will skirt eastward along the northern Gulf and into our CWA over the weekend. While the latest GFS and EURO show some subtle differences, especially on timing, both show the potential for more heavy rain and a possible severe weather threat. While the system should be progressive, any additional heavy rainfall could result in additional flash flooding in areas where the ground remains nearly saturated from recent rains. Max temps will warm into the 60s Friday and Saturday before cooling back into the 50s by Monday. Lows will lower to mid 60s on Friday. Thurs night lows rise into the mid to upper 40s. Lows will moderate into the 40s and 50s over the weekend cooling into the 30 and low 40s on Monday. .MARINE... Winds and seas will generally remain elevated through the next 7 days with periods of cautionary conditions, including tonight. Small Craft Advisory criteria may be reached over the weekend as a strong cold front approaches and pushes through the waters. .FIRE WEATHER... There are no fire weather concerns. .HYDROLOGY... The Flash Flood Watch for portions of Florida and Georgia has been allowed to be cancelled early now that the heaviest rains have moved out of the watch area. All rain will come to an end this evening as a much cooler and drier airmass moves into the region behind a strong cold front. However, we will continue to see River Flooding over the next few days. Another low pressure system may bring additional heavy rains to our region this weekend. .SPOTTER INFORMATION STATEMENT... Spotter activation is not requested. However, spotters are always encouraged to safely report significant weather conditions when they occur by calling the office or tweeting us @NWSTallahassee. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 47 63 37 56 33 / 0 0 0 0 0 Panama City 47 61 40 56 37 / 0 0 0 0 0 Dothan 41 58 34 53 31 / 0 0 0 0 0 Albany 43 59 35 54 31 / 0 0 0 0 0 Valdosta 46 62 37 55 32 / 0 0 0 0 0 Cross City 53 68 40 59 34 / 40 0 0 0 0 Apalachicola 49 64 39 57 39 / 0 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk until 10 PM EST /9 PM CST/ this evening for Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton. GA...None. AL...None. GM...None. && $$ UPDATE...LF NEAR TERM...Humphreys SHORT TERM...Barry LONG TERM...Barry AVIATION...LF MARINE...Barry FIRE WEATHER...DVD HYDROLOGY...Barry