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

Area Forecast Discussion
National Weather Service Bismarck ND
904 PM CST Tue Dec 11 2018 .UPDATE... Issued at 903 PM CST Tue Dec 11 2018 Areas of fog continue to develop across portions of north central North Dakota, and the southern James River Valley per NDDOT webcam, GOESEast, and surface observation trends through 03 UTC. The fog is most dense and with the greatest areal coverage across the lower Souris Basin and into the Turtle Mountains. Will continue to monitor trends should a Dense Fog Advisory become necessary. UPDATE Issued at 534 PM CST Tue Dec 11 2018 No significant change to the forecast for tonight with this update. A rain and snow mix across the southern James River Valley will continue to shift east over the next 1-2 hours. && .SHORT TERM...(This evening through Wednesday) Issued at 223 PM CST Tue Dec 11 2018 A trough of low pressure now moving through the James river valley will keep some likely chances for rain and snow across the southeast through early this evening. CAM models have been seeing some fog developing following the trough passage across the far eastern counties, and have added fog using the HRRR as the primary model. Considered some patchy freezing drizzle as the dry air moves in behind the system this evening, however their seems to be sufficient ice aloft to prevent much of this. Wednesday will see another clipper move in from Montana. This will bring some gusty winds across the southwest. Looked at NAM and GFS soundings, and bumped the winds up about 10 mph over SuperBlend guidance, but still did not reach advisory category. But some linkup potential for breezy to windy conditions Wednesday afternoon and evening southwest. The clipper will also spread some low chances for rain and snow, but pops have trended lower with each successive run so not impressed with teh precipitation potential. Wednesdays highs will reach into the lower 40s southwest and 30s elsewhere. .LONG TERM...(Wednesday night through Tuesday) Issued at 223 PM CST Tue Dec 11 2018 The extended looks dry and mild as a broad ridge moves east into the northern plains Thursday and Friday. A weak but dry clipper moves through Saturday, followed by a warmup again through the end of next week. Current indications show the 6 to 10 day temperature outlook would be exceptionally warm if the low levels mix out by next weekend. Currently we have mid 40s for highs southwest and 30s elsewhere, but even upper 40s would be possible in a good mixing environment. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 903 PM CST Tue Dec 11 2018 Areas of freezing fog will continue to develop across central North Dakota tonight with LIFR visibility possible. VFR conditions are expected across western North Dakota tonight. Westerly winds will increase across western North Dakota Wednesday afternoon, spreading into the central during the evening behind a cold front. Gusts of 30-35kts are forecast. Low level wind shear is possible Wednesday afternoon across the west with strong winds off the surface. Scattered rain and snow showers are also possible tomorrow with the passage of the front. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PA SHORT TERM...WAA LONG TERM...WAA AVIATION...PA
Area Forecast Discussion
National Weather Service Caribou ME
913 PM EST Tue Dec 11 2018 .SYNOPSIS... A cold front will cross the region later tonight as weak low pressure tracks east across the Gulf of Maine. High pressure will build across the region later Wednesday through Thursday and remain over the area on Fri. && .NEAR TERM /THROUGH WEDNESDAY/... 9:13 pm update: A weak area of low pressure is moving up the Midcoast of Maine with a Norlun trough expected as the weak meso low pulls away overnight. Thus far, the returns on the KGYX and KCBW radars have not been all that impressive with nothing more than about 15 dbz returns. Light snow was reported at Rockland and the visibility briefly dropped to 3/4 mile before quickly improving to 9 miles. Some very light snow or flurries has reached KBHB and also flurries have been observed in a few spots in far northern Maine. It still seems reasonable that some locations especially along the Hancock County coast and outer islands will locally pick up a few inches of snow overnight. As it is not looking all that impressive on radar will hold the course with no advisories. That said, with a high fluff factor, we can`t entirely rule that some spot picks up several inches of snow, but based on the latest radar returns it is not looking likely. The latest few runs of the HRRR have been consistent that most the accumulation will be over by around 10Z Wed morning. Made some tweaks based on the latest observations and trends, but nothing all that drastic. Previous discussion: The tricky part of the fcst tngt will be the potential of a compact Norlun event for msly Wrn coastal Downeast areas, spcly late tngt into erly Wed morn. The consensus of 12z synoptic scale and a bunch of recent hrly meso model output suggests that a meso low ovr the Casco Bay will come under the influence of initial s/wv energy from the great lks this eve, and then some additional s/wv energy from Nrn QB late ngt. This interaction will likely result in an area of ocean sn to xpnd ENE from the Gulf of ME toward the mid Maine coast and Wrn coastal Downeast areas lathe this eve into the late ngt hrs, with potential brief mdt sn rates between 1 and 4 am for coastal Hancock county. With this fcst update, we increased PoPs to categorical and sn amts to just below wntr wx adv thresholds alg the immediate Hancock coast and outer islands. Due to the tmg of the event late at ngt, it will be difficult to real tm reports, so monitoring radar ref trends will be important in the event we need to go with wntr wx hdlns in this small area of our FA. In any event, any organized snfl or coastal areas will quickly wind down to sct sn shwrs aft 6 am Wed as the upper trof axis crosses the area. Elsewhere, skies will become ptly to msly cldy ovrngt as SC ahead of the cold front and s/wv from Nrn QB apchs the FA. Isold sn shwrs ovr the Rgn with perhaps sct sn shwrs ovr the mtns can be xpctd late tngt into Wed morn with the passage of these features with ovrngt lows not as cold as last ngt due to greater xpctd cld cvr. Following the cold front, sn shwrs should end and skies will gradually become msly clr to ptly cldy by Wed aftn as brisk NNW winds cont. Hi temps Wed aftn will be similar to tdy, but the wind chill factor will make it feel much less comfortable. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Sfc high pressure cntrd to the west of CWA at the start of the short term pd. Clr skies and lgt winds wl mean another night of well-blo zero temps acrs the north with some favored locations ovr nrn Aroostook possibly making another run at -20F by daybreak tho H9 temps wl be warming by 12z. Temps wl be moderating thru the end of the week with maxes on Fri likely to climb close to normal values. Upr lvl ridge building acrs the northeast likely to be undercut by weak wv zipping thru srn New England Thu night. On Fri H5 heights rise to +560dm with highs u20/nr 30 acrs the north and climbing abv frzg in Downeast areas for the first time in a week. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Both the 12z GFS and EC keep the nrn and srn streams separate ovr the weekend. Cannot rule out chc pcpn Fri night into Sat with the upr lvl trof crossing CWA with lkly pops rmng south of the coast as main upr low rmns deep into the srn U.S. CMC indicates a little more phasing as it brings H5 low slightly further north than rmng guidance does on Fri. Models vary aft 00z Sun with EC much stronger with sfc high as it builds in fm the Great Lks keeping the secondary low ovr the coastal Carolinas as opposed to the GFS off of the mid-Atlantic with just an open wave trof on CMC as it is much more progressive with system and wl mostly discount this soln. Temps wl slide to slightly blo normal by the end of the long term. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: Nrn TAF sites will begin VFR this eve then transition to MVFR SC cld cvr late tngt into Wed morn, then sct out to VFR again by Wed aftn. Downeast sites will be MVFR or low IFR tngt, with KBHB likely becoming IFR in a short pd of steady lgt snfl late tngt. Both sites should transition back to VFR durg the morn Wed and remain so Wed aftn. SHORT TERM: VFR conditions expected through the end of the week. Restrictions look to lower beginning Fri night into Sat depending on the track of the low pressure system. && .MARINE... NEAR TERM: Initially lgt winds and seas, then winds increase late tngt into Wed morn to SCA behind a departing sfc low movg E across the Gulf of ME and cold front. SCA winds will then cont thru the remainder of the day as llvl cold advcn increases ahead of Can sfc hi pres from Nrn QB. Went with a blend of NWPS/WW3 guidance for fcst wv hts. SHORT TERM: SCA conditions will linger into the very early part of the short term. After this time winds and seas will remain below SCA levels through the end of the week. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory from 5 AM Wednesday to midnight EST Wednesday night for ANZ050>052. && $$ Near Term...CB/VJN Short Term...Farrar Long Term...Farrar Aviation...CB/VJN/Farrar Marine...CB/VJN/Farrar