textproduct: Gray - Portland

SYNOPSIS

One more hot and humid day is in store as a cold front will approach and eventually cross the region overnight. Showers and thunderstorms will be possible along and ahead of the front through the day today. A few storms may be strong to severe, and all rain may be heavy at times considering how humid the air mass is. Much drier weather arrives Friday, with comfortable temperatures and breezy westerly winds. The cooler and drier weather will continue into the weekend.

NEAR TERM /THROUGH TODAY/

Marine fog and stratus continue to push inland this morning...but it remains shallow. This is evident on satellite...as fog/stratus layer is diverted around the Camden Hills and not really blossoming until reaching the higher terrain of Androscoggin and Kennebec Counties. With winds generally light southwest this should remain the trend thru the morning.

It will be one more hot and humid day across the area. Temps in the upper 80s to lower 90s will be common. Slightly more cloud cover will help to keep the coverage of 90 degree temps and 95 plus degree heat indices limited to parts of southern NH. The heat advisory remains in effect for those areas.

Otherwise attention will be on the approaching cold front. A well defined S/WV trof is crossing into the Great Lakes this morning and will be merging with decaying convection over MI. However the convective picture is rather complicated today. There will likely be some WAA convective activity early today...followed by the front itself in the evening. Each will carry different hazard threats. Any early convection will have more favorable shear profiles for supercells and potential hail. The later convection has straighter forecast hodographs but a more favorable thermodynamic profile for wind gusts or downbursts. SPC has upgraded the severe outlook for today to slight risk...even if the coverage may remain more scattered. I currently have gusty winds and small hail attached the the midday and evening thunder. I also have heavy rain wording attached given the PWAT values well above normal.

SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/

Cold front will cross the region tonight. Finally some drier air will work into the area and flush out the humidity. It may take until morning...but once it does it should happen all at once with westerly breezy winds kicking up. Opted to bump winds/gusts up from NBM based on mixing and wind profiles aloft. Aside from choppy conditions on local waterways it will be a very pleasant day.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Update...Little change to the extended from the latest NBM guidance. A rather small tweak...but did lower thunder chances for Sun afternoon as the local area does not look to be in a favorable synoptic location for elevated chances.

Previous discussion... Overview: *High Pressure moves in for the weekend

*Cold front moves in Saturday night into Sunday

*High Pressure returns for the start of next week.

Details: A zonal 500mb pattern should allow for near-average temperatures for the end of the week. Temperatures generally look to be in the upper 70s and lower 80s on Saturday. High pressure should keep things mostly dry Saturday.

Saturday night, a cold front arrives from the west. The front should move through the area during the day Sunday, and should being some showers and storms to the area. Uncertainty is still high on the exact placement of the front and its parent low, but conditions should generally improve through the day Sunday.

Early next week, high pressure moves in with a mostly zonal pattern remaining. Highs will be pretty similar to what they should be Friday and Saturday, with upper 70s and lower 80s forecast Sunday through the first half of the week.

AVIATION /06Z THURSDAY THROUGH MONDAY/

Short Term...Areas of LIFR CIGs mainly creeping into parts of western ME this morning. This is occurring mainly over the Midcoast into the Kennebec River Valley. The LIFR visibility is largely confined to the immediate coastline...including RKD. This will more or less slowly expand thru sunrise. AUG and RKD are the only terminals forecast to be impacted by this marine layer. There will be a threat for SHRA/TSRA at all terminals this afternoon and evening...but more likely at HIE and LEB than the others. Local MVFR or lower is possible in any convection. VFR conditions expected tonight thru Fri...with breezy conditions during the day.

Long Term...VFR expected through the day on Friday and Saturday. Saturday evening through the first half of Sunday, restrictions may lower as a cold front moves through the region, bringing showers and storms. Conditions gradually improve Sunday and VFR returns by Monday.

MARINE

Short Term...Areas of fog will be present on the local waters...especially north of Casco Bay thru tonight. Showers or thunderstorms may hold together long enough to reach the waters this evening...and may contain gusty winds if they do. Much drier air will arrive late tonight or Fri morning. Westerly winds may gust up to 25 kt at times.

Long Term...Winds slacken through Friday evening, and shift to southerlies at 8-12kts by the end of the day Saturday. Winds lighten up by the second half of Sunday, with a wind shift back to Northwesterlies expected by Monday morning. 2-4 ft seas are expected through the whole period and SCA issuance is not likely at this time.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Heat Advisory until 8 PM EDT this evening for MEZ018-019. NH...Heat Advisory until 8 PM EDT this evening for NHZ008-010-011- 015. Heat Advisory until 8 PM EDT Thursday for NHZ012-013. MARINE...None.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Dense Fog Advisory until 8 AM EDT this morning for MEZ022- 025>028. NH...Heat Advisory until 8 PM EDT this evening for NHZ012-013. MARINE...None.