textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes with this forecast update.

KEY MESSAGES

1. A cold front crossing this afternoon will bring chances for scattered thunderstorms. A few storms may become strong to severe with gusty winds and possibly some hail.

2. Dry weather prevails Thursday through the weekend under high pressure. Shower chances increase early next work week.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

The warm front that brought last night's rain fall will be into northern Maine this morning with the forecast area within the warm sector of an area of low pressure over Quebec. Overcast skies early this morning will give way to mostly sunny skies by mid day. Surface heating combined with dew points in the mid 60s to near 70 degrees will allow for surface based CAPE to build to over 1500 J/kg ahead of an approaching cold front. CAMs are in decent agreement that the front will cross the mountains early afternoon and will push offshore this evening. Deep layer shear around 35 kts in combination sufficient instability will allow for at least isolated thunderstorms this afternoon along the front with some storms capable of becoming strong to severe with gusty winds and hail. CAMs continue to show very dry air above 700 mb that will be hostile to updrafts so coverage will likely be limited for storms. CAMs generally favor the mountains/foothills of Maine towards central Maine for the best chances for storms with some chances extending southwestward through coastal Maine. Thunderstorms will likely be pushing offshore around 6 PM.

KEY MESSAGE 2 DESCRIPTION...

High pressure builds over the Northeast Thursday in the wake of Wednesday cold front. A cooler and drier airmass will be in place with highs ranging from the low 70s north to low 80s and dew points in the 40s and 50s. Pleasant weather will continue through the weekend with highs moderating into the low to mid 80s and afternoon sea breezes likely along the coast. Ensembles show troughing will deepen over the Northeast Monday into the middle of next week that will favor more in the way of shower chances.

AVIATION /03Z WEDNESDAY THROUGH SUNDAY/

Through 06Z Thursday...SHRA have pushed east of AUG/RKD with low cigs and fog bringing IFR/LIFR conditions from CON and MHT to TAFs sites east. HIE and LEB will likely remain MVFR. There will be varying rates of improvement towards 12Z with VFR becoming more likely after 12Z. Mainly VFR through Wednesday night with a cold front bringing chances for TS from 18Z to 22Z. Coverage will be too limited to put in the TAF but TEMPO restrictions cannot be ruled out.

Outlook... Thursday-Sunday: Generally VFR conditions are expected as high pressure settles over the region.

MARINE

Waves will be on a downward trend today while they will still remain at or above 5 feet into Thursday morning. Steady south winds with gusts to 25 kts will continue today before a cold front crosses this evening shifting winds offshore with lighter gusts. Winds and seas remain below SCA thresholds Thursday afternoon through the weekend under high pressure.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ150-152- 154.