Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/04/18

Area Forecast Discussion
National Weather Service Hastings NE
605 PM CST Wed Jan 3 2018 .UPDATE... Issued at 559 PM CST Wed Jan 3 2018 Forecast models are hitting the fog pretty hard with the 15Z SREF showing up to around 75 percent of its members with 1 mile or less visibility in spots tonight. The 21Z RAP and 22Z HRRR are also indicating fog with less than 1 mile visibility should develop later tonight across many of our Nebraska counties. Therefore, will expand mention of fog in our overnight forecast further east and increase expected coverage and visibility reductions. Am also going to add mention of fog to our Hazardous Weather Outlook. && .SHORT TERM...(This evening through Thursday) Issued at 324 PM CST Wed Jan 3 2018 Satellite and observations continue to show a fairly narrow band of stratus through the eastern part of the forecast area. In the west, there are some higher clouds that are moving into the area. There are a couple of questions for tonight. Several of the models show that the current band of clouds will dissipate, but should return as the sun goes down this evening. Have kept some clouds around during the remainder of the afternoon and into the evening, but expect that the clouds will be a little higher in the west. As the lower clouds that are to the north move back into the area later tonight there could be some fog developing along the clearing line. There are some concerns with the fog. The higher clouds across the west could make it a little harder to get some fog, but the temperatures will still drop off and the temperature/dew point spread becomes very small. Since the complete extent of the lower clouds is a bit uncertain, have kept fog across the western part of the forecast area. The clouds should start to clear out of the area during the morning on Thursday. With the sunshine and a little warm advection, temperatures should be a little warmer for Thursday. .LONG TERM...(Thursday night through Wednesday) Issued at 324 PM CST Wed Jan 3 2018 Northwest flow continues Thursday night through Saturday. There will be a cold front Thursday night with another push of colder air for Friday, but temperatures should remain around the same as Thursday for much of the area. By Saturday, warm advection kicks in again, there should be sunshine and with south winds increasing during the day, the temperatures should rise closer to near normal temperatures. They will still be a little below, but it will be the first day near freezing in nearly two weeks, at least for some locations. Saturday night into Sunday night there will be an upper level wave that moves through, as well as a cold front. Models have a few differences in timing and strength of the system. This has caused there to be some concern for what will happen. At this time, expect there to be some precipitation from late Saturday night through Sunday evening, somewhere around the area. Another concern will be the precipitation type. There will be warmer temperatures during the day and there could be a change to rain. Monday through Wednesday will be another dry period. There will be northwest flow across the area and with that some temperature changes, but Monday and Tuesday should be warmer days with a cool down for Wednesday. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 559 PM CST Wed Jan 3 2018 See update section above regarding fog concerns for tonight. Have certainly decreased visibilities in the TAFs with this update and may need to go lower at KGRI if this fog pans out. Will need to watch out for low clouds and fog tonight through at least mid morning tomorrow and if fog does form it could take longer to burn off then currently projected. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ UPDATE...Wesely SHORT TERM...JCB LONG TERM...JCB AVIATION...Wesely
Area Forecast Discussion
National Weather Service Mount Holly NJ
933 PM EST Wed Jan 3 2018 .SYNOPSIS... Low pressure rapidly intensifies as it quickly moves northward to the Atlantic waters east of New Jersey Thursday morning, then to the Canadian Maritimes by Friday. Arctic high pressure will then build into the East through most of the weekend. Low pressure is forecast to track near our area early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... * Major winter storm to impact the region later tonight and Thursday* No major changes with the 930 PM update. Snow is beginning to move into our area and banded structure is already developing upstream. As a result, the going forecast looks on track. There remain some differences between the high resolution models as the HRRR depicts most of the mesoscale banding off shore, while most of the other models depict banding, especially east of the I 95 corridor. Otherwise, bend of LAV/MET/MAV guidance was used with temperatures. Pops increase from southwest to northeast tonight, hitting on a thermal gradient providing lift just offshore for precipitation formation. Snow will be widespread by the morning commute. Mesoanalysis and more general details below... Mesoanalysis: A high impact winter storm is still expected to track up the east coast tonight and Thursday. The first issue is the actual formation of this low. Model data has struggled for the past several days regarding how the storm forms with competing low centers. Modeling has shifted to a more western center closer to the main temperature gradient. A look at SPC mesoanalysis currently shows the western low being more dominant. With this being said, the location of convection will still be an issue as we draw closer to the event. The further offshore convection fires the less moisture moves into our region. As a result, the trend has been more precipitation showing up with the afternoon model data given tendencies to the western low. On the flip side, a concern still remains that dry air on the backside of the storm could still lower QPF totals from the current forecast. The low pressure system will organize overnight and spread snow northwest into our region. The 12Z 1/3 NAM soundings are near freezing a few thousand feet up near the coast so some sleet could mix in at times tonight. Snow within the bands does have the potential to be moderate or heavy at times with mesoscale models keying on this. Thus, large differences in totals over short ranges could occur. Winds will increase as well with bufkit soundings yielding gusts from 30-50 mph in spots. Blowing and drifting of snow are major concerns. General storm highlights: Timing: Overnight and Thursday. 1. Blowing and drifting snow will occur regionwide. This will reduce visibilities and make travel very difficult. The wind may result in downed trees and power outages as well. The impacts will be rather high from the blowing and drifting! 2. Snow totals look to range from a couple of inches in the Southern Poconos up to ten inches at the shore. The Thursday morning commute will be very difficult with the snow, blowing snow and cold. 3. Based on the increased totals, we expanded the warning further northwest into Philadelphia and Trenton. An advisory was issued further north and west. Although some locations may not reach the 2- 3 inch criteria, impacts such as blowing snow and timing with the morning rush were taken into account. 4. A blizzard warning was issued along the coast given higher winds forecasted. 5. Try to get any needed travel done this evening if possible. While the advisories/warnings start this evening it may not be until late evening or overnight before snow starts. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... The storm will be the main show. Temperatures were a blend of MET/MAV and generally in the 20`s. Pops are categorical across the board, slightly lower in the Southern Poconos given the concern over dry air on the backside of the storm. Snow should end from southwest to northeast in the afternoon. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... Summary...Dangerous cold in the wake of the Nor`easter through at least the first half of the weekend; a warm-up early next week as low pressure tracks near our area. Synoptic Overview...A deep upper-level trough in the East weakens and shifts offshore Saturday night and Sunday. The flow then backs ahead of the next trough sliding across the Midwest to the Southern Plains. This combined with a return flow on the backside of departing cold high pressure will allow the arctic air to start eroding. Warming takes place early next week as a low pressure system tracks near our area, however a more southern track may keep colder low-level air in longer especially north and west of I-95. For Thursday night through Sunday...Intense low pressure will be moving into the Canadian Maritimes Thursday night into Friday. This time frame will be dominated by arctic air and dangerous cold. Some moderation is expected Sunday though as the major upper-level trough lifts out. Until then, gusty northwesterly winds will combine with very cold air temperatures leading to dangerously low wind chills across the entire area. The gusty winds may continue blowing and drifting snow into Friday. There is a Wind Chill Watch for the southern Poconos for Thursday night into Friday. Some areas in this region are forecast to experience wind chills right around -25F at times. For now, we will keep the Watch going. Elsewhere, a Wind Chill Advisory looks to be needed for Thursday night and Friday morning with wind chills down around -10F. Additional Wind Chill Advisories will probably be needed for Friday night and Saturday night. The extent of this will depend on how much the winds stay up, although it will be so cold just light winds will have an impact on the wind chill. Overall, a very very cold time frame followed by some improvement on Sunday as the arctic high starts to shift offshore. For Monday through Wednesday...As the flow initially backs ahead of the next system, warm air advection occurs as high pressure is to our east. Low pressure is forecast to track near our area with a cold front moving through Monday night. Some guidance however is farther south with the primary surface low development, and if this occurs the warming would be slowed especially in the low levels. This could result in a period of some mixed/icy precipitation to then even some rain as enough warming should take place. More specifics as we get closer. It then look to turn colder for Wednesday. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Rest of this afternoon...VFR with an increase in clouds at or above 15,000 feet. Light and variable winds overall. Tonight...VFR through the evening for most terminals. Snow develops generally in the 03-09z timeframe with earlier onset mainly at ACY and MIV. The ceilings will lower to MVFR with visibilities dropping to MVFR/IFR. Lower confidence with the onset of snow and lower conditions, especially farther inland. Northerly winds around 5 knots, increasing late to 10-15 knots. Thursday...Snow with IFR conditions (LIFR at times within heavier snow where hourly rates could be 1-2 inches) to nearly all terminals. The snow will end from southwest to northeast during the afternoon. North to northwest winds increase to 15-25 knots with gusts 30-40 knots resulting in considerable blowing and drifting snow. The ceilings/visibilities should improve by later in the afternoon. Moderate confidence. OUTLOOK... Thursday night through Saturday...VFR with northwest winds 10-20 knots with gusts 25-35 knots. The winds are expected to diminish some Friday night into Saturday. Moderate to high confidence. Sunday...VFR with west to southwest winds less than 10 knots. High confidence. Monday...MVFR conditions possible with a chance for some mixed precipitation or rain. Southwesterly winds 5-10 knots. Low to moderate confidence. && .MARINE... Seas will gradually build tonight and continue well above five feet through Thursday. We are still anticipating gales on both the bay and ocean waters. Storm conditions are possible as well near buoy 44099. No changes to marine headlines as conditions gradually deteriorate tonight. Precipitation may be mixed with sleet and rain further offshore. Outlook... Thursday night through Saturday...Gale conditions through the period, with at least moderate freezing spray (especially near the coast) Thursday night and Friday and a good chance of heavy freezing spray Friday night and Saturday. Gale warnings will be needed after the Storm Warning expires for the Atlantic Delaware waters and is already in effect for Delaware Bay and the New Jersey coastal waters through Friday night. Low end gales may occur for a time Saturday. A Freezing Spray Advisory is in effect Thursday night and Friday, and a Heavy Freezing Spray Watch is in effect Friday night and Saturday. There is high confidence in gales through at least late Friday and in freezing spray being an increasingly hazardous threat. Saturday night...Small craft advisory conditions are forecast, with light to moderate freezing spray. Sunday and Monday...Sub-advisory conditions area anticipated. && .TIDES/COASTAL FLOODING... With the rapidly deepening cyclone off the coast and the full moon having recently occurred, coastal flooding has become more of a concern for the Thursday morning high tide. Reports from the Manasquan area earlier today indicated water reaching portions of low-water crossings and subsequently freezing. Though minor flooding was not indicated at any of the official forecast gauges this morning, the levels will increase with Thursday morning`s high tide as the low moves into the Mid-Atlantic waters. The forecasts at tidal gauges along the New Jersey and Delaware coasts have increased the past couple of days, as well. This morning`s forecasts show fairly widespread marginal flooding at gauges from Sandy Hook to Lewes with some potential up portions of Delaware Bay. Given these trends, forecast ambient temperatures, and current water temperatures along the coast, a Coastal Flood Advisory was issued for the NJ/DE coast around Thursday morning`s high tide. Stagnant water at high tide has the potential to freeze, creating an additional impact to the potential for flooding. && .CLIMATE... Arctic cold will continue its hold on the region through Monday morning with what we think will be increasing adverse impact on the infrastructure as one of the most persistent cold outbreaks in recent memory extends through Sunday January 7. Additional record lows and record cold maximum temperatures should be set Friday, Saturday and Sunday. The following list includes records that may fall. Record Low Temps for Friday 1/5: also Record low Max Allentown (ABE).....not likely 15F (1968) Reading (RDG).......not likely 12F (1904) Atlantic City (ACY).not likely 18F (1968) Philadelphia (PHL)..not likely 14F (1904) Wilmington (ILG)....not likely 16F (1904) Trenton (TTN).......not likely no rer avbl Georgetown (GED)....9F (1958) no rer avbl Mount Pocono (MPO)..not likely no rer avbl Record Low Temps for Saturday 1/6: also Record low Max Allentown (ABE).......not likely 13F (1942) Reading (RDG).........not likely 15F (1912) Atlantic City (ACY)...4F (1981) 17F (1912) Philadelphia (PHL)...4F (1896) 18F (1942) Wilmington (ILG)...7F (1924 and 1946) 20F (1988) Trenton (TTN)...5F (1896 and 1904) no rer avbl Georgetown (GED)...6F (1969) no rer avbl Mount Pocono (MPO).....not likely no rer avbl Record Low Temperatures for Sunday 1/7: Allentown (ABE)....-4F (1942) Atlantic City (ACY).4F (1884) Philadelphia (PHL)..4F (2014) Wilmington (ILG)....3F (2014) Reading (RDG).......0F (2014) Trenton (TTN).......2F (2014) Georgetown (GED)....8F (2014) Mount Pocono (MPO)..-8F (2014) On the consecutive day below freezing watch: PHL had a high of 33 degrees on Wednesday, ending their consecutive days at or below freezing at 7 days. This is tied for the 30th longest stretch of below freezing days. The rest of our climate sites are still on track to continue the stretch of below freezing through at least Sunday. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Winter Weather Advisory until 7 PM EST Thursday for PAZ054-055- 060>062-101>103-105. Winter Storm Warning until 7 PM EST Thursday for PAZ070-071- 104-106. Wind Chill Watch from Thursday evening through Saturday afternoon for PAZ054-055. NJ...Winter Weather Advisory until 7 PM EST Thursday for NJZ001- 007>010. Winter Storm Warning until 7 PM EST Thursday for NJZ012- 015>019-021. Coastal Flood Advisory from 8 AM to 2 PM EST Thursday for NJZ013-014-020-022>027. Blizzard Warning until 7 PM EST Thursday for NJZ013-014-020- 022>027. DE...Coastal Flood Advisory from 8 AM to 2 PM EST Thursday for DEZ002>004. Blizzard Warning until 7 PM EST Thursday for DEZ003-004. Winter Storm Warning until 5 PM EST Thursday for DEZ001-002. MD...Winter Weather Advisory until 7 PM EST Thursday for MDZ008. Winter Storm Warning until 5 PM EST Thursday for MDZ012-015- 019-020. MARINE...Freezing Spray Advisory from 6 PM Thursday to 6 PM EST Friday for ANZ430-431-450>455. Gale Warning until 5 AM EST Saturday for ANZ430-431-450>453. Storm Warning from 6 AM to 3 PM EST Thursday for ANZ454-455. && $$ Synopsis...Gorse Near Term...Gaines/Johnson Short Term...Gaines Long Term...Gorse Aviation...Gorse Marine...Gaines/Gorse Tides/Coastal Flooding... Climate...
Area Forecast Discussion
National Weather Service Tucson AZ
250 PM MST Wed Jan 3 2018 .SYNOPSIS...A weak disturbance will pass through Southern Arizona bringing a few sprinkles or light showers to the area late tonight into Thursday. Dry conditions will then prevail Friday into Saturday. A few showers may develop north of Tucson Saturday night and Sunday. Unseasonably warm daytime temperatures will also continue into next week. A stronger storm system may affect the region by the middle of next week. && .DISCUSSION...Scattered to broken clouds were noted on satellite imagery this afternoon across much of Southeast Arizona. Though the area is currently under the influence of an upper ridge, conditions will change in the coming hours as a shortwave trough approaches from the southwest. Model solutions over the last 24 hours have continued to trend upward with regard to PoPs, especially from Tucson southward and eastward tonight into Thursday. Several hi-res models including the HRRR and both U of A WRFs show an area of showers pushing through the region from southwest to northeast late this evening into early Thursday morning. A few showers may linger through the day Thursday, but the trough axis and any associated precip should be clear of the area by Thursday evening. Any accumulations over the next 24 hours will be very light, generally a trace to only a few hundredths of an inch at best. We`ll dry out under ridging for Friday and Saturday with a few passing high clouds. Upper level flow will flatten out late Saturday into Sunday with a trough breezing quickly through the four corners. We may see a few showers across the White Mountains Saturday night as this happens, but nothing significant. More ridging builds in for Sunday and Monday, with a weak wobble in the flow potentially firing off some showers for the Whites again on Tuesday. The forecast could then get a lot more interesting, as medium range models are currently advertising a strong area of low pressure to move through the state next Wednesday or Thursday. The preliminary PoPs inherited from the midnight shift were increased slightly for days 7 and 8, though it is likely the forecast will morph several times over the next week as the details get clearer. Daytime temperatures this week will continue to run on the warmer side, generally from 6 to 12 degrees above average. && .AVIATION...Valid thru 05/00Z. Cloud bases will continue to lower this evening allowing for SCT-BKN clouds around 10-15k ft AGL. Expect BKN-OVC skies as low as 5-8k ft AGL after midnight as a weak weather system moves in. Some virga and -SHRA will be possible tonight and into Thursday morning mainly south and east of KTUS. Gusty SFC winds will diminish this evening and become terrain driven at less than 12 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Dry conditions will prevail this evening before a weak weather system passes through tonight into Thursday morning creating a slight chance of showers mainly south and east of Tucson. Winds will remain gusty through this evening before decreasing to less than 10-15 mph and becoming terrain driven. Drier air will return through Saturday before another chance of showers arrives Saturday night into Sunday across the White Mountains. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ ECC/Pegram Visit us on Facebook...Twitter...YouTube...and at