Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 260531 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 1231 AM EST Sun Jan 26 2020 .SYNOPSIS... Low pressure has developed south of the region and will track into southern Maine tonight and through the state tomorrow afternoon. The low pulls away Monday with high pressure slowly building toward the area from the northwest through the end of the week. && .NEAR TERM /THROUGH TODAY/... 1226 AM Update: Chgs this update include bumping PoPs up to 100 percent for the remainder of the ngt into erly Sun morn, but keeping the wx-precip types/cats from the prior update. Also, we added patchy fog for late tngt into Sun for areas of the Rgn xpctd to have sfc dwpts greater than 34 deg F. Otherwise, fcst hrly temps/dwpts were updated thru the remainder of the ngt - merged with erly morn fcst values, with the trend of each xpctd to cont to slowly rise thru this tm. Orgnl Disc: Sfc low currently located near Philly with fire hose aimed up acrs Long Island into Upstate NY courtesy of 50-60kt LLJ in conjunction with RFQ of upper level jet. Sfc low wl track up along the coast tonight with upr level features mvg thru the area late tonight into the mrng hrs. As sfc low tracks along the coast pcpn wl spread into wrn areas after 00z tonight in the form of rain along the coast with sleet and freezing rain north of interior Downeast. GFS is the only model now indicating pcpn wl start off as snow but it has had a cold bias this winter, likely due to the new core. Hv sided closer to the NAM and it indicates the dreaded warm nose will be located thru almost the entire CWA at onset of pcpn. Sfc temps wl drop acrs srn areas until about 00z bfr beginning to rise as warm advection kicks in. Nrn areas wl see temps drop until about midnight bfr rising into the aftn tomorrow. Temps wl lkly bcm nearly steady fm about daybreak into early afternoon in the lwr 30s acrs the Crown which wl be a challenge btwn pin-pointing areas for frzg rain and rain. As of now temps are blw frzg north of a Moosehead to Houlton line with temps abv frzg over interior Downeast areas. Temps lkly wl have a hard time dropping over Downeast tonight with the exception of most of Washington County as they tend to hold onto cold air the longest. Hv dropped srn Penobscot and interior Hancock out of the winter wx advisory for tonight as the only locations that look to see any frzg rain wl be the very far northern reaches of the area. Sfc low still expected to track through the state drg the aftn hrs with dry slot working into srn areas in the mrng and heading east by late morning with pcpn quickly winding down bfr wrap- around gets going ovr the northwest as cold air filters in fm Canada at the same time. Locally hvy rain likely to occur acrs the coast tomorrow morning with total rainfall amounts around 1 inch. This may result in ponding of water on roadways in the morning. Ellsworth has reported a snow depth of 6" with Dedham having 5 inches. Snowpack in that area should be able to absorb some of the rain with the frost layer right near the surface therefore not expecting any flash flooding. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... There are still significant discrepancies among guidance regarding the evolution of the upper level low and its surface reflection Sunday night. The 12z and 18z runs of the NAM remain outliers from the rest of guidance in showing a 500mb vorticity maximum pivoting northeastward over Maine faster from 0-6z Monday. Went with a non-NAM consensus to close out the storm and favored the regional GEM and ECMWF, which show a slower progression of the negatively tilted vort max and deepening of its surface reflection into the 990mb range over Aroostook County. This low will continue to deepen and is forecast to move over or near Presque Isle and Caribou before exiting northeastward into New Brunswick around 6z. Near the center and southeast of the low, rain is expected, while snow is favored along a deformation axis to the north and west over the North Woods and Saint John Valley, where the winter weather advisory holds on the longest. Favorable snow crystal growth is expected with forecast soundings showing at least a few hour period of strongly negative omega over the DGZ, which will become saturated. Most snow accumulations are sub-advisory, but will approach the 4 inch threshold along our western border with Quebec. Precipitation will taper to snow showers during the day Monday, before tapering further to flurries Monday night into Tuesday morning. A subsidence inversion will lock in low stratus through Tuesday morning, with gradual clearing later in the day as drier low to mid level air pushes in from the north. A shortwave trough will approach the region late Tuesday night into Wednesday morning. There is still considerable disagreement on how far into Maine this will go. Even if it impacts the area, limited moisture should limit precipitation to flurries and perhaps some snow showers where orographic enhancement occurs. Increased PoPs to near 10 percent, but did not go high enough to trigger slight chance wording or put flurries in at this time. && .LONG TERM /TUESDAY THROUGH SUNDAY/... A weak cold front is expected by early Wednesday evening behind the departing shortwave. Overall, quiet conditions are expected Wednesday night through Saturday morning with a ridge of high pressure in control. Tweaked NBM lows downward on Wednesday and Thursday nights given that mostly clear skies are expected and NBM guidance was above the 50th to 75th percentiles. A major winter storm is possible Saturday night into Sunday, but this is at the end of the forecast period and may still change substantially. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... NEAR TERM: Low MVFR/IFR cigs acrs the north this afternoon before dropping to IFR overnight at all terminals. Light rain wl affect Downeast terminals after 06z tonight through end of TAF valid time. Further north, mixed precip will move from south through north tonight into tomorrow. LLWS likely at all terminals late tonight into tomorrow morning. SHORT TERM: Sunday night to Monday: IFR to LIFR across Aroostook County terminals. MVFR Downeast with isolated rain and snow showers. Mon night to Tuesday afternoon: MVFR with low ceilings and scattered snow showers/flurries across Aroostook County terminals. VFR with ceilings marginally above 3kft AGL Downeast. Tuesday evening through Thursday: Mainly VFR. MVFR occasionally possible across Aroostook County terminals with a slight chance of flurries or a brief snow shower Wednesday morning. && .MARINE... NEAR TERM: Winds increase to gales tonight and rmn high through the morning hours. Seas remain above 5 feet through the end of the period with small craft conditions likely needed for all waters through the day Sunday. SHORT TERM: Winds and waves subside to SCA over the outer waters and below SCA for the intra coastal waters Sunday night. Winds and waves subside below SCA Monday night into Tuesday, then continue below SCA through Thursday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until noon EST today for MEZ002-005- 006-010. Winter Weather Advisory until midnight EST tonight for MEZ001- 003-004. Winter Weather Advisory until 7 AM EST this morning for MEZ011- 017-031-032. MARINE...Small Craft Advisory until 8 AM EST this morning for ANZ052. Gale Warning until 8 AM EST this morning for ANZ050-051. && $$ Near Term...VJN Short Term...Strauser Long Term...Strauser Aviation...VJN/Strauser Marine...VJN/Strauser is the U.S. government's official web portal to all federal, state and local government web resources and services.