textproduct: Gray - Portland

WHAT HAS CHANGED

With conditions expected to be fairly similar to today, the forecast for Friday has trended to have more cloud cover in portions of western ME along with a low (20%) chance of showers.

KEY MESSAGES

1. Increased fire weather concerns may carry into Friday as mostly dry weather continues, but Friday will not be as breezy.

2. No significant weather impacts are expected into next week, but unsettled weather does make a return after a dry weekend.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Good mixing and a tight gradient will continue the breezy and dry weather the rest of this afternoon with gusts of 25 to 35 mph. These conditions will bring increasing fire weather concerns, especially across NH where the breeziest conditions and lowest RH will be. Forecast soundings are also showing sufficient moisture and around 100 J/kg of CAPE above 5000ft AGL to keep skies mostly cloudy skies from the western ME mountains southward to the Midcoast.

Winds and clouds will begin to diminish toward sunset as the daytimes mixing wanes, and this trend will continue overnight. The exception may be western ME where a shortwave may bring back more clouds overnight. Otherwise, it will be a seasonably cool night with lows primarily in the mid 20s to lower 30s.

Similar but slightly cooler conditions are expected on Friday with good mixing once again and highs mostly in the 50s. This may bring more fire concerns as dry air aloft mixes down, but it won't be as breezy as winds aloft won't be as high as today. Based on forecast soundings, gusts should generally be limited to 20-25 mph. NH will see mostly to partly sunny skies, but with broad cyclonic flow aloft western Maine (especially toward the Kennebec Valley and Midcoast) could again see periods of mostly cloudy skies and possibly a couple of showers as forecast soundings do show that same moist layer and a similar amount of MUCAPE as today.

Friday night will again be seasonably cool with temperatures mostly ranging from the mid 20s to lower 30s.

KEY MESSAGE 2 DESCRIPTION...

All signs point to a dry weekend as low pressure gets suppressed well to the south of New England. Temperatures moderate during this time with highs in the upper 50s and lows in the upper 30s. The low and attendant upper trough move offshore Sunday night and by Monday afternoon it cuts off. With strong high pressure deepening over the Canadian Maritimes, this system is going to get hung up in our vicinity. Monday should be mostly dry while this process occurs, but by Monday this vertically stacked low is going to be the source of some unsettled weather. The secondary source for later in the week is going to a boundary moving northeastward from the plains, but the big question is going to be how long high pressure can stave off these two sources. For the coastal low, there is still some disagreement amongst ensemble camps, but the majority suggest we stay on the outer fringes off it with low chance showers, breezy winds, and increased cloud cover being the extent of the sensible weather. By midweek the consensus is that the low pressure gets pushed along as another trough begins to dig into the region, but how this plays out is currently split. The GFS and Canadian ensembles suggest the high pressure to our northeast weakens and the boundary moving out of the plains is able to make into the region as the next trough digs in. This combined with waves of low pressure tracking along the boundary would almost certainly be the wetter solution. However, the Euro ensemble camp seems to be painting a drier picture with high pressure holding its ground and suppressing the boundary just a little bit farther to the southwest. Still, this could be the difference between widespread showers and isolated showers. For now I feel that the blanket chance PoPs through Thursday provided by the NBM is reasonable to cover this uncertainty.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Through Friday...VFR expected. Winds gusts of 25-30 kt this afternoon will diminish toward 00Z this evening and then continue to lessen overnight. Can't rule out a shower or two in the vicinity of RKD and AUG on Friday, but chances look much too low for TAF mention. It also won't be as breezy Friday, but gusts up to 20 kt are possible out of the N/NW.

Outlook...

Friday night: VFR.

Saturday-Monday: Generally VFR conditions expected with no significant weather.

Tuesday-Thursday: Generally VFR, but MVFR possible with shower activity. Coverage of any showers next week is highly uncertain at this time.

MARINE

Through Friday night...Winds and seas are expected to remain below SCA levels. Winds will be mainly out of the north to northwest but may try to become more onshore closer to the coast Friday afternoon as the seabreeze attempts to develop.

Generally sub-SCA conditions expected on the waters into midweek. Around midweek we will have to keep an eye on the possibility of elevated seas in the coastal waters as we may see low pressure tracking over the Gulf of Maine.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...None.