Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
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
50
437 FXUS61 KCAR 050011 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 811 PM EDT Tue Jun 4 2024 .SYNOPSIS... Weak high pressure drifts south of the Gulf of Maine tonight. A weak disturbance rotates north to south over Maine on Wednesday. A flattening ridge works overhead into Wednesday night. An upper level low then slowly approaches from the west Thursday into Friday and moves across the area this weekend. && .NEAR TERM /THROUGH WEDNESDAY/... 810 pm update... Cumulus has dissipated with loss of daytime heating with mid- high clouds streaming over top of ridge acrs the west. Expect a fairly quite night overnight with light winds. Patchy fog will be possible over portions of the area with the mostly likely occurring along the coast once again. No changes needed with this update. Prev discussion blo... Tonight, surface high pressure drifts south of the Gulf of Maine waters tonight with flow turning W-WNW tonight aloft with increasing moisture spilling over the ridge. Partly cloudy skies expected tonight and remaining dry as temperatures fall back into the low to mid 50s with light and variable winds. Tomorrow morning expecting the large cutoff low over the Maritimes to remain locked in place thanks to the -NAO blocking in the North Atlantic. A piece of vorticity will rotate southward out of Northern Quebec between the low and the 500mb ridging over the Eastern Great Lakes. Warm, increasingly moist air and partly sunny skies will allow for a convective situation in the afternoon. High temperatures top out in the low to perhaps mid 80s for much of the CWA with the exception along the Downeast coast where an afternoon sea breeze develops. Tomorrow, dew points will increase with Td`s into the low 60s so a touch of humid weather for the Central Highlands and Interior Downeast with mid to upper 50s dew points north. Hi-res cams continues to depict a variety of solutions on the development of convection tomorrow. Based on the latest modeled soundings the likelihood of reaching the convective temperatures looks really good. Modeled soundings showing steep low level lapse rates 9-9.5C/km given steep inverted "v" look. Tomorrow, mid level lapse rates are "okay" with 6-6.5C/km across the area. SBCAPE looks to develop in the 1000-1500j/kg range but relatively dryer low levels depending on where you are in the state. Freezing levels are going to be on the 10.5kft to 11.5kft range tomorrow. While the low levels are dry the mid level RHs look to be in the 75-85% range. PWATs tomorrow do increase close to the 90th percentile so if any convection can develop brief heavy rain is possible as storm motion NNW to SSE will be slow. Lastly, confidence in stronger storms is low given the drier low levels but with storm motion NW-SE cannot rule out a "surprise" stronger system as it has happened before in similar setups. Overall, isolated to scattered showers and some thunderstorms is possible. Given the thermodynamics and overall upper level dynamics lacking in some aspect expecting mainly garden variety showers and storms. SPC continues to paint the area in "general thunder" and will keep any enhanced wording out of the grids for now. Any rain will be welcomed given the long term deficits... && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Shortwave ridging will continue but slowly break down as Maine remains between upper level lows over the Great Lakes and Gulf of Saint Lawrence. Any convective showers and thunderstorms Wednesday afternoon will dissipate with loss of daytime heating Wednesday evening. Clearing skies are expected across much of the area Wednesday night, especially north of Baxter State Park. Most areas will remain dry on Thursday with just a slight chance of showers over most of the area. Greater shower chances, more cloud cover, and slightly cooler temperatures are expected across southern and western portions of the forecast area, while far northern Maine is expected to remain warm and partly to mostly sunny. Patchy fog is possible each night into the morning along the coast and extending inland. There is more uncertainty by Friday regarding the timing of the initial push of positive vorticity advection (PVA) on the eastern edge of the upper level low. However, the greater chances for rain and cooler temperatures will again be across southern and western portions of the area, with greater chances for breaks of sunshine and slightly warmer temperatures across far northern Maine. A majority of guidance keeps the 500mb PVA west of the area through Friday evening, so it is possible some areas may stay dry into the evening. Forecast soundings indicate warmer and drier air aloft, especially from 500mb and above both Thursday and Friday, leading to poor lapse rates. For this reason, PoPs were lowered compared to the NBM and thunderstorm chances should remain low (less than 10% chance within 25mi) both days. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... The leading edge of PVA along the eastern edge of the upper level low will move across the area Friday night into Saturday night, although precise timing remains uncertain. This will bring a batch of more widespread, slow moving showers and a period of steadier rain to the area. Moisture aloft and steepening lapse rates will bring back the chance of thunder, especially by Sunday. However, extensive cloud cover and limited surface heating should preclude more widespread and stronger thunderstorm activity. Fog could also occur, particularly along the coast or over areas where skies clear, but confidence was too low to include in the long range forecast. Temperatures are expected to remain seasonable with highs generally in the upper 60s to lower 70s and lows in the upper 40s to lower 50s. Guidance disagrees on the progress of the upper level low by early next week, but there is good agreement among ensemble guidance that large scale upper level troughing will continue across the Northeastern United States through the middle of next week regardless. This will result in continued unsettled weather with near normal temperatures and chances for showers and possibly thunderstorms. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: VFR overnight with BKN cigs at BGR with mid-deck pushing in from the west. BGR and HUL may see MVFR in BCFG late tonight with IFR at BHB for most of the nighttime hours. Winds will be light and variable next 24 hours. SHORT TERM: Wednesday night: VFR, except IFR or lower possible mainly at southern airports due to patchy fog. Light winds. Thursday: VFR. Southeast winds 5-15 kts. Thursday night to Friday night: VFR at Aroostook County airports. MVFR/IFR possible at southern airports extending into GNR with showers and patchy fog at night into the early morning. Southeast winds 5-15kts. Saturday to Sunday: Predominantly MVFR/IFR with showers. Southeast winds 5-15 kts. && .MARINE... NEAR TERM: Winds/seas below SCA conditions through tomorrow. W winds less than 15kt tonight becoming S tomorrow. Seas 1ft or less tonight becoming 1-2ft tomorrow. Patchy fog may reduce vsby tonight into tomorrow. SHORT TERM: Winds will remain below advisory levels and generally below 20 kts through the period. Seas will also remain around 2 feet or less. Fog is expected at times, particularly Wednesday night into Friday morning. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Buster/Sinko Short Term...MStrauser Long Term...MStrauser Aviation...Buster/Sinko/MStrauser Marine...Buster/Sinko/MStrauser