textproduct: Gray - Portland

SYNOPSIS

High pressure will bring continued dry weather through early Saturday. By Sunday and especially Sunday night...an approaching front will bring the threat of rain to the region... which may begin as a wintry mix in the mountains and foothills. Next week looks to remain mild and unsettled with additional chances for rain.

NEAR TERM /UNTIL 6 PM THIS EVENING/

620 PM Update...Very little change to the going forecast early this morning as temperatures remain in check and strato-cu in the southeastern zones is moving out as forecast.

Previously...

Offshore low pressure will move away from the region this morning while deep layer ridging moves in. The drying from aloft should scour out this pesky early morning stratus deck which is currently being trapped under a strong inversion around 4,000 ft on the coastal plain and across southern NH. The consensus is for drying in that layer today, so where it's cloudy early on this morning those areas should see more and more sun as the morning progresses.

Winds will be light and variable today with a consensus in MOS yielding highs in the 30s area-wide.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/

Deep layer ridging tonight will allow for efficient radiational cooling with light/calm winds and mostly clear skies. For lows, utilized a blend of the MOS guidance which yields lows in the single digits and teens on the coastal plain and portions of southern NH. In the interior the better radiators may dip lower than -10F.

Friday will feature a good deal of sunshine early on but a developing WAA pattern may allow for an increase in clouds, especially mid afternoon onward. SFC temperatures will respond to the light southwesterly winds and top out in the mid to upper 30s, with some lower 40s possible southeastern zones.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Update...Have added some light freezing rain/light freezing drizzle to the going forecast for late Sat afternoon and Sat night into early Sunday as the low levels moisten and upper levels warm as per latest forecast soundings.

Previously...

At 500 MB zonal flow over the E Pacific initially acts as ave generator for the W CONUS, and digs out broad tough trough there. This allows some ridging to develop over the E half of the CONUS, which eventually works its way into New England through the weekend. This will provide warmer temps, and mainly dry conditions Sat, with a potential for precip moving in on Sat night and Sunday. By early next week start to see some weak ridging over the W CONUS, which allows closed low to shift towards Hudson Bay, setting up a deepening trough to our W, which will see several rounds of waves move NE on the upstream side of it, making for an unsettled period early to middle of next week. Still, being on that side of the trough, it should stay on the milder side, with precip outside the mtns, falling mainly as rain.

Late Sun and Sunday night could see some mixed precip to start things off most everywhere, except the coast and far S NH, but should transition to rain everywhere as temps rise Sun night. The sequence of events with the waves moving around the base of the trough to our W still remain uncertain, and forecast confidence, but will continue to lean toward the ECMWF and its ensembles for the timing of precip, although even the Euro has show run to run variability. Still best chance for precip will be centered around Monday at this point, with the potential for a break Tue/Tue night, with more precip arriving on Wed, but this is low confidence and subject to change.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Short Term...MVFR/low VFR deck over the coastal plain is expected to thin out as the morning progresses as the air mass dries out a bit more. Otherwise, VFR conditions with light winds are expected today through Friday.

Long Term...Expecting mainly VFR into Saturday night, with flight restrictions possible on Sunday, but more likely Sun night into Monday. Some light freezing rain or freezing drizzle possible Saturday night. Low confidence.

MARINE

Short Term...Low pressure to the east will continue to induce northerly flow over the coastal waters. High pressure arrives overnight into Thursday, remaining overhead into late week. Small craft conditions are not expected through Friday.

Long Term...Winds generally stay on the light side Friday Sunday, but do pick up from the SE Sun night into Monday, and may need an SCA.

GYX WATCHES/WARNINGS/ADVISORIES

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