textproduct: Gray - Portland

WHAT HAS CHANGED

Frost/Freeze headlines have been cancelled as temperatures quickly rebound into the 40s. OTherwise no changes to today's forecast.

KEY MESSAGES

1. After a cold start, today will be dry with breezy northwest winds. Frost and Freeze headlines may be needed again tonight for portions of the interior.

2. Slow moving low pressure will bring rain Wednesday through Friday resulting in beneficial rainfall.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Upper trough swings east of the area early this morning with high pressure building in from the west. Skies will start off mostly clear with cu developing with surface heating through late morning. The NW gradient from the incoming high and mixing to around 800 mb will allow for NW winds to increase late morning into the afternoon with gusts 20 to 25 mph. These NW winds will also inhibit much in the way of a sea breeze allowing coastal areas to be the warm spot with highs near 60 degrees. High temperatures will taper to the north with areas near the Canadian Border having highs restricted to the 40s.

High pressure will crest south of the area early tonight allowing for winds to relax. Mostly clear skies combined with near calm winds will allow for efficient radiational cooling from sunset until around midnight tonight. Low pressure moving east through the Great Lakes region will start to spread some cirrus across the area west to east after midnight with clouds thickening and lowering into Wednesday morning. These clouds may put a halt on radiational cooling which may limit the opportunity for frost. The going forecast brings lows into the low to mid 30s for portions of the interior and near freezing into the foothills. Trends in the advancing cloud cover will need to be monitored with the next forecast package to see where Frost and Freeze headlines may be needed.

KEY MESSAGE 2 DESCRIPTION...

Low pressure will move into New England by Wednesday, and a warm front moves northeastward through the afternoon. Precipitation should be fairly light and widespread, with light and steady rain looking to continue through Thursday morning. Rain becomes more showery on Thursday, but dense clouds will keep conditions fairly socked in and chilly through the day. Rain picks up in intensity Thursday evening as a cold front slowly moves through with a more intense slug of rainfall. Some thunder cannot be ruled out especially across southern NH Thursday night but the steady rain and moist adiabatic environment should inhibit the rain and showers from becoming thunderstorms. While it will be a soggy few days, rainfall amounts should not be impactful. Heavy downpours are not favored, as PWATs are fairly dry for a storm like this in the Spring. Showery weather is likely to continue on Friday as well, with some wraparound rain possible as the aforementioned low moves eastward.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

Through 12Z Wednesday...VFR prevails. WNW winds will increase this morning with gusts 15 to 20 kts by early afternoon. This should keep sea breeze off the coastal terminals. Winds will dissipate this evening. Clouds increase from west to east after 06Z Wednesday while CIGs remain VFR.

Outlook:

Wednesday: AM VFR, MVFR in the afternoon due to lowering CIGs and rain.

Thursday and Friday: MVFR due to low CIGs, showers, and possible isolated thunder. Areas of IFR possible as well, especially in periods of heavier rain.

Saturday: Improvement to VFR.

MARINE

Winds and seas remain below SCA thresholds today through tonight as high pressure builds in from the west and then crests south of the waters tonight.

Low pressure approaching form the west will increase southeast winds Wednesday with these winds bringing SCA conditions into Thursday. As low pressure crosses overhead and then exits east Friday winds will diminish and then shift out of the north, with seas continuing to remain at 3-5 ft.

GYX WATCHES/WARNINGS/ADVISORIES

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