Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 111334 AFDGYX Area Forecast Discussion National Weather Service Gray ME 834 AM EST Wed Jan 11 2017 .SYNOPSIS... A front will move through the area this morning with precipitation coming to an end and warm air spilling in from the west. The warmth continues into Thursday before a cold front arriving Thursday night brings colder temperatures back into the area on brisk northwest winds Friday. Saturday will be the coldest day of the week before temperatures begin to moderate back toward normal levels Sunday and Monday. Another warm up is expected through the middle of next week as low pressure in the center of the country pumps warm air northward ahead of it and into New England. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
13z update... Quick update to adjust temp/td/sky/pop/wx grids. Rain has push east of the forecast area this morning and aside from a few sprinkles in the mountains the remainder of the day should be dry. With the exception of the mountains...skies will be quickly clearing from west to east through late morning. Temps already in the lower to mid 40s should push into the upper 40s to lower 50s. Winds have settled down in mid coast areas so will be dropping wind advisories for those areas. No other changes planned attm. Previous discussion... 645 AM Update... Precipitation is quickly moving away and have cancelled the winter weather advisory for central Somerset County. Winds are still coming up along the Mid Coast where the wind advisory is in effect through 9 AM...so will leave it alone for now. Previous discussion... Precipitation now moving through the forecast area is mostly in the form of rain but some snow is falling in the higher terrain and especially towards the Canadian border where cold air is being more stubborn. Gusty SSW winds accompanying a warm front are translating warmer air northward however and expect all precipitation to either change over to rain or simply be outrun by forcing for ascent later this morning. Have kept the winter weather advisory going for central Somerset County which will have the most time with colder air in place to produce a few inches of snow. Skies will clear out from SW to NE during the day with gusty SW winds developing for the entire area behind the frontal passage. In particular, the Mid Coast of Maine remains under a wind advisory as the LLJ impinges on this area with around 50-70 kts. Temperatures will respond to the warming downslope component and readings will reach the 40s and 50s for all but the far north.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Clouds increase tonight as another fast moving, sheared out system ejects from the Great Lakes region. Overnight lows will occur early in the night due to this...bottoming out in the 20s and 30s with coastal locations around 40. We will most likely see some light freezing rain as the precipitation arrives late tonight into Thursday. As warmer air nudges northward freezing rain will change to plain rain by Thursday morning. Since we currently have a winter weather advisory out, will hold off on issuing anything for this event to avoid confusion...but will mention in the HWO. Once again strong SW winds will drive temperatures up with the frontal fracture straddling northern New England. Readings in the mid 40s to lower 50s will be common and are of course well above normal for this time of year. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Expect a sharp cold front to move through from northwest to southeast rather quickly Thursday night. Some rain showers are expected along and ahead of the front, with the best forcing for ascent riding northward along the front as it moves through, bringing the best rain chances to western and northern parts of the area. By Friday morning temperatures will be falling by cold advection more so than by radiational cooling. A pocket of cold air from Canada pours into the region during the day on Friday. Temperatures aloft at 850MB drop about 23C from 00Z Friday to 00Z Saturday, with about 14C of that occurring from 12Z to 00Z. Such strong cold advection does not always lead to falling temperatures during the day, but it is indicative of superb low level mixing. Cold air pouring in aloft will aid in transporting stronger winds to the surface. Models are showing about 40 to 50KT of northwesterly winds at 850MB as the peak of cold advection crosses the area around midday which will likely translate into a period of gusty winds. Will keep wind gusts below advisory levels for now, but this is worth keeping an eye on due to the excellent mixing potential especially downwind of the mountains where downslope conditions will aid in the process. High pressure builds into the area Friday night into Saturday with winds diminishing. Saturday will be the coldest day of the forecast with highs in the north only in the low to mid teens and in the mid 20s in southern areas. The coldest night should be Saturday night into Sunday morning as the elongating high pressure becomes best situated over the region setting the stage for good radiational cooling conditions. Have blended the SuperBlend with the MEX and undercut the typical cold spots in order to introduce some better low temperature numbers into the forecast Sunday morning. Models often like to show warmer low temperatures the second night after a cold front as temperatures aloft begin to moderate, but this is rarely the case. There is still some room to go lower with forecast lows Sunday morning as dewpoints should be near zero. One factor working against excessive cooling is the lack of a fresh snow cover. In fact, a good portion of the populated corridors may have little to no snow left on the ground at this point. This should not prevent radiational cooling in these areas, but a fresh snow pack would allow for even colder conditions. Elongated area of high pressure stretching from the Great Lakes to New England remains in control of the weather Sunday and Monday. This will spell gradually moderating temperatures with pretty good radiational cooling possible each night, depending on any cloud cover which passes through. On Tuesday, surface high pressure shifts offshore. A large trough of low pressure in the southern jet stream over the central United States will force ridging over the East Coast for the middle of next week. This will pump warm air northward again into New England ahead of the slow moving trough. Models are now in fairly good agreement than any precipitation associated with this trough will not arrive until Wednesday, with the warm air favoring rain as the precipitation type. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... Short Term...IFR/LIFR/MVFR ceilings/vsby continue tonight in rain showers and will improve to VFR later this morning. A strong LLJ will contribute to cause wind shear of 50 kts at FL015 today despite gusty SSW surface winds. Areas of MVFR conditions possible on Thursday, especially in the west. Long Term...Conditions improve to VFR Friday morning as a cold front pushes through and much drier air arrives. Cold advection leads to strong northwest winds on Friday, but these should begin to diminish Friday evening. Light winds and VFR conditions expected for the weekend. && .MARINE... Short Term...Strong south winds ahead of a front this morning will shift to the west and diminish this afternoon. Could see winds strengthening out of the southwest again on Thursday in advance of a cold front. Long Term...A strong cold front crosses the waters from the northwest Friday morning. Expect a stiff northwest wind on Friday with small craft conditions likely and borderline gale force gusts possible. Winds diminish Friday night into Saturday as high pressure moves over the area and remains nearby through early next week. && .TIDES/COASTAL FLOODING... Strong south to southeast flow overnight will create a storm surge of 0.5 to 1 foot. This may create some splashover or beach erosion at the time of high tide around 930 AM Wednesday. A Coastal Flood Statement has been issued to highlight the threat. && .GYX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
ME...None. NH...None. MARINE...Gale Warning until 10 AM EST this morning for ANZ151>154. Storm Warning until 10 AM EST this morning for ANZ150.
-- End Changed Discussion --
&& $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.