textproduct: Gray - Portland

WHAT HAS CHANGED

No changes were needed at this time.

KEY MESSAGES

1. After substantial rain over the last few days, we'll switch to above normal temperatures for this weekend. After a long below normal stretch of weather, outdoor recreation will be in high demand and area inland and ocean waters remain very cold.

2. Above normal temperatures continue into the work week with chances of scattered showers and thunderstorms on Tuesday and Wednesday, which should also be the two warmest days of the year so far.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

After some early morning fog today, southwesterly winds will kick in and start our warm stretch of temperatures this weekend. As the previous forecast shift noted, with highs well into the 70s this weekend, this will be the first well above normal stretch in a while, and the expectation is that lots of people will be anxious to get out and enjoy that weather. The concern is that inland and ocean waters remain very cold. For the ocean waters we have continued a Beach Hazard Statement to highlight those waters temps in the 40s still. Inland, rivers and lakes are cold, plus recent rainfall has the rivers running swift. So we have also have gone ahead and continued a Special Weather Statement for inland cold waters.

There's a low chance of isold to widely sct showers later this afternoon and tonight with weak WAA, but these look light at best.

A cold front will move across the forecast area on Sunday with little fanfare as the air mass will be quite dry. Warm weather continues Sunday but a drier and cooler air mass arrives with high pressure Sunday night with lows returning to the 30s in mountains zones and 40s elsewhere.

KEY MESSAGE 2 DESCRIPTION...

As an upper level ridge axis moves across the northeast CONUS, above normal temperatures persist into the work week. Monday highs are expected to range from the upper 60s and lower 70s north, to the upper 70s and lower 80s south. High pressure at the surface will lead to mainly dry day with plenty of sunshine peaking out.

The ridge flattens out a little bit on Tuesday as a shortwave approaches. Most of the synoptic forcing and enhanced mid-level flow will likely stay north of the border but there should be enough of a glancing blow to at least bring some showers and storms to northern portions of the forecast area late Tuesday afternoon and into the evening. GFS forecast soundings suggest some weak to moderate instability by the afternoon hours in the 1000 to 1500 J/kg range depending on the parcel trace. Shear will be rather marginal with stronger mid/upper level flow displaced to the north, but we could still see some deep layer shear on the order of 30 to 35 knots. This environment would be favorable for a few stronger multicell storms with gusty winds and small hail.

Wednesday afternoon/evening could see a better chance for more widespread thunderstorms as cold front moves across the region. That being said, the latest GFS forecast soundings paint a picture of slightly weaker instability and the same marginal shear. Thus a few stronger storms will be possible on Wednesday as well. As a final note fore the severe weather potential, the CSU Machine Learning Severe guidance does show some low severe weather probabilities each day for our area so it will remain a period to watch, but today's model trends seemed to have backed off a little bit with regards to the severe weather potential.

Tuesday and Wednesday will also likely be our two warmest days of the year thus far with some widespread highs in the upper 70s to the mid/upper 80s. A few lower 90s will even be possible over southern New Hampshire on Tuesday.

Any lingering showers and storms should move out of the area by Thursday morning, leading to a cooler and dry end of the work week. Highs on Thursday and Friday could mainly be in the 50s and 60s. With very little NBM spread, this cool down is a fairly high confidence forecast for being on Days 6 and 7.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Through 12Z Sunday...VFR conditions are expected for the bulk of the day today through tonight. However, there is a low prob for some patchy MVFR conditions this evening into tonight in possible showers. Southwest wind gusts around 20 kt are possible today.

Outlook:

Sunday-Sunday night...VFR expected. Gusts of 25 to 30 kt out of the west are possible during the day Sunday.

Monday/Monday night: VFR conditions expected.

Tuesday/Tuesday night: MVFR due to thunderstorms.

Wednesday/Wednesday night: MVFR due to thunderstorms.

MARINE

Still dealing with large seas between 5 and 7 feet generally across the coastal waters and will remain elevated through the weekend. Did however, lower wind gusts some for Saturday night as sharp low level inversion will exist.

Winds and seas will start to gradually relax through the day on Sunday and into Monday as high pressure settles over the waters. An approaching cold front will lead to some showers and thunderstorms mid-week with southerly winds increasing again.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Beach Hazards Statement through this evening for MEZ023>028. NH...Beach Hazards Statement through this evening for NHZ014. MARINE...Small Craft Advisory until 5 AM EDT Sunday for ANZ150-152-154.