textproduct: Gray - Portland

WHAT HAS CHANGED

A beach hazards statement has been issued to warn of the cold water temperatures boaters and paddlecraft users will experience this weekend.

KEY MESSAGES

1. Seasonable weather to begin Memorial Day Weekend with wet weather closing it out.

2. A brief midweek warm up before cooler temperatures return late week.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

High pressure will hold today and the weak pressure gradient will offer the sea breeze a chance to push inland this afternoon. It will be mostly sunny and temps seasonable to slightly warmer than normal, so given the cold inland waters we will maintain the SPS for that recreational hazard. High pressure will steadily retreat allowing cloud cover to increase thru tonight. That should stave off any significant radiational cooling and bring an end to the frost/freeze headlines for the time being. Rainfall will likely hold off until Sun morning for the forecast area, but will not be denied this time. Model guidance has settled on a mainly Sun thru Sun night event. QPF is fairly light for such a longer duration rain event, so there are no concerns regarding flooding. But the onshore winds and precip will lead to a very raw day and temps may fail to reach 50 degrees in some locations. Based on ensemble guidance it is looking like a fairly widespread 0.25 to 0.5 inch event, with the heavier amounts near the Mass border and lightest in the upper Kennebec River Valley.

KEY MESSAGE 2 DESCRIPTION...

A short but noticeable warm up will arrive Tuesday-Wednesday. Westerly flow should preclude sea breezes and cool onshore flow. Combined with some downslope warming off the higher terrain in NH, it looks to be a warm two days with highs approaching 80 degrees, but tolerable humidity. Some guidance suggests a backdoor cold front may be lurking across Maine on Wednesday to bring a cool down, while other scenarios do not bring cooler temperatures in until the end of the week. But in any case the trend will be towards cooler temperatures by next Thursday- Friday with height falls and building troughing over the Northeast.

A trough axis is progged to drop south from Canada Tuesday night into Wednesday, resulting in an increasing chance for scattered showers, but widespread rain remains unlikely. Precipitation chances become uncertain beyond next Wednesday. The large-scale pattern becomes quite complex as guidance suggests an omega block developing next week. This would pump up a strong ridge to our northwest over central Canada, with troughing near or offshore the Northeast U.S.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

VFR conditions prevail. Expect some onshore winds for coastal terminals this afternoon with a sea breeze developing. Late tonight some MVFR CIGs may begin to creep into parts of the forecast area ahead of rain/showers.

Outlook...

Sunday and Monday: Widespread MVFR and areas of IFR possible as rain moves into the forecast area. Fog will become possible by Mon. Near the coast southeasterly surface gusts of 20 kt are possible.

Monday Night: Gradual improvement towards VFR by morning.

Tuesday: VFR conditions expected.

Tuesday Night: VFR conditions expected. Local MVFR or lower conditions possible in showers but low confidence.

Wednesday: VFR conditions expected. Local MVFR or lower conditions possible in showers but low confidence.

Wednesday Night: VFR conditions expected.

MARINE

High pressure remain in control of the coastal waters thru Sun. Sea breeze is likely during the afternoon under the weak pressure gradient. As a warm front lifts across the waters Mon onshore winds will increase and marginal SCA conditions are possible as southerly flow builds seas to near 5 feet. The period will be approaching 10 seconds, so fairly marginal, but may pose an increasing rip current risk bordering on high surf. Winds then become offshore by midweek as high pressure builds in from the west.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Beach Hazards Statement through this evening for MEZ023>028. NH...Beach Hazards Statement through this evening for NHZ014. MARINE...None.